WorldWideScience

Sample records for circulating air ductwork

  1. Air Dispersion Characteristics and Thermal Comparison of Traditional and Fabric Ductwork using Computational Fluid Dynamics

    Science.gov (United States)

    Andreopoulou, Areti

    This thesis research compares the air dispersion and thermal comfort characteristics of conventional diffuser and fabric-based ductwork systems. Heating, ventilation, and air-conditioning (HVAC) systems in buildings produce and regulate airflow traveling through ductwork. The performance characteristics of conventional ductwork are compared with recent advancements in fabric-based ductwork. Using computational fluid dynamics (CFD) analysis, thermal and air distribution flow patterns are compared between the two types of ductwork and preliminary thermal comfort and efficiency conclusions are drawn. Results of the Air Distribution Performance Index (ADPI) for both ducting systems reflect that, under the given test conditions, the fabric duct system is approximately 23% more comfortable than the traditional diffuser system in terms of air speed flow uniformity into the space, while staying within the Effective Draft Temperature comfort zone of -3 to +2°F.

  2. 75 FR 31223 - Energy Conservation Program for Consumer Products: Test Procedure for Residential Central Air...

    Science.gov (United States)

    2010-06-02

    ... installation with a hot-air furnace must contain a blower to circulate air through the indoor coil and ductwork... on the furnace blower to circulate air through the indoor coil, ductwork, and the furnace...

  3. Reducing Energy Usage in Residential and Industrial Buildings via the Sealing of Heating and Air Conditioning Ductwork

    Science.gov (United States)

    Witriol, Norman; Katz, Myron; McKim, Robert; Erinjeri, Jinson; Saber, Aziz

    2003-03-01

    Many existing residential and industrial heating and cooling systems have leaky ductwork. These leaks result in large energy losses, and thus significantly higher than necessary utility costs. We will discuss the use of extensions of well investigated cost effective sealing methodologies to ductwork, and quantify the energy savings that can be achieved by sealing these leaks.

  4. Validation of the criteria for initiating the cleaning of heating, ventilation, and air-conditioning (HVAC) ductwork under real conditions.

    Science.gov (United States)

    Lavoie, Jacques; Marchand, Geneviève; Cloutier, Yves; Lavoué, Jérôme

    2011-08-01

    Dust accumulation in the components of heating, ventilation, and air-conditioning (HVAC) systems is a potential source of contaminants. To date, very little information is available on recognized methods for assessing dust buildup in these systems. The few existing methods are either objective in nature, involving numerical values, or subjective in nature, based on experts' judgments. An earlier project aimed at assessing different methods of sampling dust in ducts was carried out in the laboratories of the Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST). This laboratory study showed that all the sampling methods were practicable, provided that a specific surface-dust cleaning initiation criterion was used for each method. However, these conclusions were reached on the basis of ideal conditions in a laboratory using a reference dust. The objective of this present study was to validate these laboratory results in the field. To this end, the laboratory sampling templates were replicated in real ducts and the three sampling methods (the IRSST method, the method of the U.S. organization National Air Duct Cleaner Association [NADCA] and that of the French organization Association pour la Prévention et l'Étude de la Contamination [ASPEC]) were used simultaneously in a statistically representative number of systems. The air return and supply ducts were also compared. Cleaning initiation criteria under real conditions were found to be 6.0 mg/100 cm(2) using the IRSST method, 2.0 mg/100 cm(2) using the NADCA method, and 23 mg/100 cm(2) using the ASPEC method. In the laboratory study, the criteria using the same methods were 6.0 for the IRSST method, 2.0 for the NADCA method, and 3.0 for the ASPEC method. The laboratory criteria for the IRSST and NADCA methods were therefore validated in the field. The ASPEC criterion was the only one to change. The ASPEC method therefore allows for the most accurate evaluation of dust accumulation in HVAC

  5. 24 CFR 3285.606 - Ductwork connections.

    Science.gov (United States)

    2010-04-01

    ... to UL 181A (incorporated by reference, see § 3285.4), for closure systems with rigid air ducts and connectors, or UL 181B (incorporated by reference, see § 3285.4), for closure systems with flexible air ducts... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Ductwork connections....

  6. Defining the Effectiveness of UV Lamps Installed in Circulating Air Ductwork

    Energy Technology Data Exchange (ETDEWEB)

    Douglas VanOsdell; Karin Foarde

    2002-11-30

    Germicidal ultraviolet (UVGI) lamps have a long history of use for inactivating microbial aerosols. Most reports have focused on the control of infectious diseases, such as tuberculosis (TB), in the occupied spaces of medical facilities. Ventilation duct use of UVGI has been increasing. In-duct applications are generally more concerned with controlling environmental organisms than with controlling infections agents. This document reports the results of a project to investigate the ability of UVGI lamps to inactivate representative environmental microbial aerosols in ventilation ducts. During this research, UVGI lamps were experimentally demonstrated to inactivate bioaerosols composed of vegetative bacteria, bacteria spores, or fungal spores to a reproducible degree under conditions of fixed dose. Vegetative bacteria were most susceptible to UVGI, with bacteria and fungal spores being substantially more resistant. The performance equation commonly cited in the literature for UVGI inactivation was found to generally apply, provided its parameters were known. Revision of final report DOE/OR22674/610-40030-01. Revised table 5 on page 33.

  7. Exterior exposed ductwork: Delivery effectiveness and efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Delp, W.W.; Matson, N.; Modera, M.P.

    1996-07-01

    Most of California`s light commercial buildings use air transport through ductwork for thermal distribution. The same air distribution systems are often used to provide both thermal comfort and ventilation. Some air distribution ductwork is installed on rooftops, exposed directly to the outside environment. As such, there exist potential energy penalties related to externally installed ductwork. In order to evaluate the magnitude of these penalties, a case study was conducted of a one-story community college building, located in California`s Sacramento Valley. The majority of the building`s air distribution ductwork was located on the roof. Energy-related issues studied in this case included duct-related thermal losses (duct leakage and conduction), delivery effectiveness and efficiency, thermal comfort issues and the effect of a roof retrofit (additional insulation and a reflective coating). The building in this study underwent a retrofit project involving additional insulation and a highly reflective coating applied to the roof and ducts. As part of this project, methods were developed to analyze the air distribution system effectiveness independent of the introduction of outside air through an outside air damper. A simplified model was developed to predict the effectiveness and efficiency of the distribution system. The time frame of the retrofit allowed two separate three week monitoring periods. Despite the fact that the ducts started off with a conduction efficiency of 97%, the delivery efficiency was on average only 73% (with a supply side effectiveness of 78% and return effectiveness of 92%). This is due to the losses from the ducts being located on the roof. The retrofit increased the delivery efficiency to an average of 89% (with a supply side effectiveness of 90% and return effectiveness of 99%), reducing the average energy use for conditioning by 22%. The model predicted, on average, the results within 10%, or better, of measured results.

  8. SpaceX Dragon Air Circulation System

    Science.gov (United States)

    Hernandez, Brenda; Piatrovich, Siarhei; Prina, Mauro

    2011-01-01

    The Dragon capsule is a reusable vehicle being developed by Space Exploration Technologies (SpaceX) that will provide commercial cargo transportation to the International Space Station (ISS). Dragon is designed to be a habitable module while it is berthed to ISS. As such, the Dragon Environmental Control System (ECS) consists of pressure control and pressure equalization, air sampling, fire detection, illumination, and an air circulation system. The air circulation system prevents pockets of stagnant air in Dragon that can be hazardous to the ISS crew. In addition, through the inter-module duct, the air circulation system provides fresh air from ISS into Dragon. To utilize the maximum volume of Dragon for cargo packaging, the Dragon ECS air circulation system is designed around cargo rack optimization. At the same time, the air circulation system is designed to meet the National Aeronautics Space Administration (NASA) inter-module and intra-module ventilation requirements and acoustic requirements. A flight like configuration of the Dragon capsule including the air circulation system was recently assembled for testing to assess the design for inter-module and intra-module ventilation and acoustics. The testing included the Dragon capsule, and flight configuration in the pressure section with cargo racks, lockers, all of the air circulation components, and acoustic treatment. The air circulation test was also used to verify the Computational Fluid Dynamics (CFD) model of the Dragon capsule. The CFD model included the same Dragon internal geometry that was assembled for the test. This paper will describe the Dragon air circulation system design which has been verified by testing the system and with CFD analysis.

  9. Inspection of contaminated hot cell ductwork

    Energy Technology Data Exchange (ETDEWEB)

    Muller, R.C.; Herndon, J.N.; Dagenhart, W.K.

    1989-08-01

    Radiation Sterilization, Incorporated (RSI), of Dekalb County, Georgia, has used Cesium-137 radiation sources for sterilization of medical instruments and other commercial items. The cesium is contained in welded stainless steel capsules. One of these capsules has leaked, allowing the cesium to escape and to contaminate the internals of the sterilization cells including the cell ventilation ductwork penetrating the thick concrete cell roof. This ductwork requires decontamination prior to release of the facility to resume sterilization activities. Due to the small size (20-in. {times} 24-in. cross section) and the long runs embedded in the cell roof, it was determined that remote visual inspection and preliminary radiation mapping of this ductwork was necessary. This report covers the inspection effort and evaluation of the results. 23 figs., 3 tabs.

  10. Fat, oil and grease reduction in commercial kitchen ductwork: A novel biological approach.

    Science.gov (United States)

    Mudie, S; Vahdati, M

    2017-03-01

    Recent research has characterised emissions upon cooking a variety of foods in a commercial catering environment in terms of volume, particle size and composition. However, there has been limited focus on the deposition of solid grease in commercial kitchen ductwork, the sustainability of these systems and their implications on the heat recovery potential of kitchen ventilation extract air. This paper reviews the literature concerning grease, commonly referred to as Fat, Oils and Grease (FOG) abatement strategies and finds that many of these systems fall short of claimed performances. Furthermore these technologies often add to the energy cost of the operation and reduce the potential application of heat recovery in the ventilation ductwork. The aim of this study was to develop and evaluate a novel FOG removal system, with a focus on low environmental impact. The novel FOG removal system, utilises the biological activity of Bacillus subtilis and associated enzymes. The biological reagent is delivered via a misting system. The temperature, relative humidity and FOG deposit thickness were measured in the ductwork throughout a 3month trial period. FOG deposit thickness was reduced by 47% within 7weeks. The system was found to be effective at reducing the FOG deposit thickness with minimal energy cost and impact upon the kitchen and external environment. Internal ductwork operating temperature was measured with respect to future heat recovery potential and a reduction of 7°C was observed.

  11. Stimulation of good building and ductwork airtightness through EPBD

    DEFF Research Database (Denmark)

    Guyot, Gaelle; Carrié, Remi; Schild, Peter

    Building and ductwork leakage are detrimental to energy conservation, comfort, and hygiene. They can cause building damage and it can prevent proper control of the ventilation airflow rates. Through the ASIEPI project, we have identified that while some key elements for a market transformation...

  12. Experimental and calculated calibration of ionization chambers with air circulation

    CERN Document Server

    Peetermans, A

    1972-01-01

    The reports describes the method followed in order to calibrate the different ionization chambers with air circulation, used by the 'Health Physics Group'. The calculations agree more precisely with isotopes cited previously (/sup 11/C, /sup 13/N, /sup 15/O, /sup 41 /Ar, /sup 14/O, /sup 38/Cl) as well as for /sup 85/Kr, /sup 133/Xe, /sup 14/C and tritium which are used for the experimental standardisation of different chambers.

  13. Continuous circulation apparatus for air drilling well bore operations

    Energy Technology Data Exchange (ETDEWEB)

    Stallings, J.L.

    1982-02-16

    An apparatus is disclosed for maintaining a continuous supply of air pressure downhole during a well bore drilling operation, even during the addition of a pipe section to the drill string. It consists of a housing installed at the surface of the well at the position of the drilling equipment wherein the upper end of the drill string is separated from the drive mechanism in order that a new piece of drill pipe may be added to the drill string, a flapper or closure member pivotally secured within the housing normally held in an open position by the outer periphery of the drill string and spring urged in a direction toward the open end of the sleeve through which the drive mechanism passes when the drive mechanism has been backed off or removed for the addition of a section of pipe to the drill string, and a by-pass line in communication with the interior of the housing for directing air pressure from the air supply to the housing when the flapper member is in the closed position whereby the air pressure may be circulated downwardly through the drill string for maintaining the air circulation downhole during the entire drilling operation.

  14. 30 CFR 77.305 - Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance.

    Science.gov (United States)

    2010-07-01

    ... chambers and ductwork; installation and maintenance. 77.305 Section 77.305 Mineral Resources MINE SAFETY... drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. Drying chambers, hot gas inlet chambers and all ductwork in which coal dust may accumulate shall be equipped with...

  15. Calculation of flow distribution in air reverse circulation bit interior fluid field by simplifying air flow model

    Institute of Scientific and Technical Information of China (English)

    Shuqing HAO; Hongwei HUANG; Kun YIN

    2007-01-01

    By simplifying the characters in the air reverse circulation bit interior fluid field, the authors used air dynamics and fluid mechanics to calculate the air distribution in the bit and obtained an equation of flow distribution with a unique resolution. This study will provide help for making certain the bit parameters of the bit structure effectively and study the air reverse circulation bit interior fluid field character deeply.

  16. Rapid cascade condition assessment of ductwork via robot vision

    Science.gov (United States)

    Wang, Yongxiong; Su, Jianbo

    2012-02-01

    Automatic assessment of condition in ductwork is very desirable in applications. Presented is a visual condition diagnosis approach, which is capable of processing images rapidly and achieving high accuracy rates. A hierarchical coarse-to-fine image segmentation method is employed. False alarms could thus be progressively eliminated, which is robust in strongly noisy conditions. The simple classifiers combined in a cascade quickly classify the detected images and discard the uninterested (non-object) images, leaving more computation power on promising object-like regions. The features of each simple classifier are selected based on the Bhattacharyya distance. The cascade can be viewed as an object-specific focus-of-attention mechanism. Experimental results validate the effectiveness and rapidity of the proposed assessment method.

  17. Fogging formulations for fixation of particulate contamination in ductwork and enclosures

    Energy Technology Data Exchange (ETDEWEB)

    Maresca, Jr., Joseph W.; Kostelnik, Lori M.; Kriskivich, James R.; Demmer, Rick L.; Tripp, Julia L.

    2015-09-08

    A method and an apparatus using aqueous fixatives for fogging of ventilation ductwork, enclosures, or buildings containing dust, lint, and particulates that may be contaminated by radionuclides and other dangerous or unsafe particulate contaminants, which method and apparatus are capable of (1) obtaining full coverage within the ductwork and (2) penetrating and fixing the lint, dust and large particles present in the ductwork so that no airborne particles are released during or after the application of the fixative. New aqueous fogging solutions outperform conventional glycerin-based solutions. These aqueous solutions will fog using conventional methods of application and contain a surfactant to aid wetting and penetration of the lint and dust, a binder to stabilize loose or respirable particles, and an agent to aid in fogging and enhance adhesiveness. The solutions are safe and easy to use.

  18. Liquid Circulation in a Multi-tube Air-lift Loop Reactor

    Institute of Scientific and Technical Information of China (English)

    刘永民; 刘铮; 穆克; 袁乃驹

    2000-01-01

    A multi-tube air-lift loop reactor (MT-ALR) is presented in this paper. Based on the energy conservation, a mathematical model describing the liquid circulation flow rate was developed, which was determined by gas velocity, the cross areas of riser and downcomer, gas hold-up and the local frictional loss coefficient. The experimental data indicate that either increase of gas flow rate or reduction of the downcomer diameter contributes to higher liquid circulation rate. The correlation between total and the local frictional loss coefficients was also established.Effects of gas flowrate in two risers and diameter of downcomer on the liquid circulation rate were examined. The value of total frictional loss coefficient was measured as a function of the cross area of downcomer and independent of the gas flow rate. The calculated results of liquid circulation rates agreed well with the experimental data with an average relative error of 9.6%.

  19. Air circulation and cooling effect through artificial screes : a preliminary case study (Fribourg, Switzerland)

    Science.gov (United States)

    Dorthe, J.; Abbet, D.; Delaloye, R.

    2009-04-01

    Keywords: Air circulation; sorted gravel heap; thermal regime; temperature measurements; electrical resistivity tomography Occurrences and thermal impacts of air circulation throughout a natural porous medium have been detected and investigated for the last decade in many talus slopes located in mid-latitude regions (e.g. in the Swiss Alps and Prealps). The process makes sporadic permafrost to occur far below the regional lower limit of discontinuous permafrost. It is commonly accepted that connected systems of large voids facilitates the movement of air. Which void size and structure do prevent the circulation of air and the significant cooling of the ventilated terrain is still a remaining open question. The investigation of artificial gravel heaps consisting each of material of different grain-size could provide key data to solve the problem. By the end of a 4-week period of cold weather (daily mean temperature often colder than -5°C) in December 2008 / January 2009, with 10-20 cm deep laying snow cover, investigations similar to those performed on natural talus slopes (visual observations, ground surface temperature measurements, 2D electrical resistivity tomography) have been carried out on 8 artificial gravel heaps from 2 to12 m high located in a gravel pit close to Fribourg (620 m a.s.l., Switzerland). The study was aimed to analyse the air circulation and its impact on the thermal regime of the artificial screes depending on the grain-size of the consisting material (>4 mm to 16-32 mm), the volume (10-2000 m3) and the porosity of the heaps. The first results of this ongoing study can be resumed hereafter. Any evidence of air circulation was not observed on the heaps with a grain-size pit holder also mentions that the interior of the large heaps can be sometimes frozen until the beginning of summertime. At this stage, it can be stated that an open-void debris accumulation consisting of clasts with a grain-size as small as about 1 cm does not prevent an

  20. Drought Variability in Eastern Part of Romania and its Connection with Large-Scale Air Circulation

    Science.gov (United States)

    Barbu, Nicu; Stefan, Sabina; Georgescu, Florinela

    2014-05-01

    Drought is a phenomenon that appears due to precipitation deficit and it is intensified by strong winds, high temperatures, low relative humidity and high insolation; in fact, all these factors lead to increasing of evapotranspiration processes that contribute to soil water deficit. The Standardized Precipitation Evapotranspiration Index (SPEI) take into account all this factors listed above. The temporal variability of the drought in Eastern part of Romania for 50 years, during the period 1961-2010, is investigated. This study is focused on the drought variability related to large scale air circulation. The gridded dataset with spatial resolution of 0.5º lat/lon of SPEI, (https://digital.csic.es/handle/10261/72264) were used to analyze drought periods in connection with large scale air circulation determinate from the two catalogues (GWT - GrossWetter-Typen and WLK - WetterLargenKlassifikation) defined in COST733Action. The GWT catalogue uses at input dataset the sea level pressure and the WLK catalogue uses as input dataset the geopotential field at 925 hPa and 500 hPa, wind at 700 hPa and total water content for entire atmospheric column. In this study we use the GWT catalogue with 18 circulation types and the WLK catalogue with 40 circulation types. The analysis for Barlad Hydrological Basin indicated that the negative values (that means water deficit - drought period) of SPEI are associated with prevailing anticyclonic regime and positive values (that means water excess - rainy period) of SPEI are associated with prevailing cyclonic regime as was expected. In last decade was observed an increase of dry period associated with an increase of anticyclonic activity over Romania. Using GWT18 catalogue the drought are associated with the north-eastern anticyclonic circulation type (NE-A). According to the WLK40 catalogue, the dominant circulation type associated with the drought is north-west-anticyclonic-dry anticyclonic (NW-AAD) type. keywords: drought, SPEI

  1. Long-term air temperature variation in the Karkonosze mountains according to atmospheric circulation

    Science.gov (United States)

    Migała, Krzysztof; Urban, Grzegorz; Tomczyński, Karol

    2016-07-01

    The results of meteorological measurements carried out continuously on Mt Śnieżka in Karkonosze mountains since 1880 well document the warming observed on a global scale. Data analysis indicates warming expressed by an increase in the mean annual air temperature of 0.8 °C/100 years. A much higher temperature increase was recorded in the last two decades at the turn of the twenty-first century. Mean decade air temperatures increased from -0.1 to 1.5 °C. It has been shown that there are relationships between air temperature at Mt Śnieżka and global mechanisms of atmospheric and oceanic circulation. Thermal conditions of the Karkonosze (Mt Śnieżka) accurately reflect global climate trends and impact of the North Atlantic Oscillation (NAO) index, macrotypes of atmospheric circulation in Europe (GWL) and Atlantic Multidecadal Oscillation (AMO). The increase in air temperature during the 1989-2012 solar magnetic cycle may reveal a synergy effect to which astrophysical effects and atmospheric and oceanic circulation effects contribute, modified by constantly increasing anthropogenic factors.

  2. Utilization of ventilation air methane as a supplementary fuel at a circulating fluidized bed combustion boiler.

    Science.gov (United States)

    You, Changfu; Xu, Xuchang

    2008-04-01

    Ventilation air methane (VAM) accounts for 60-80% of the total emissions from coal mining activities in China, which is of serious greenhouse gas concerns as well as a waste of valuable fuel sources. This contribution evaluates the use of the VAM utilization methods as a supplementary fuel at a circulating fluidized bed combustion boiler. The paper describes the system design and discusses some potential technical challenges such as methane oxidation rate, corrosion, and efficiency. Laboratory experimentation has shown that the VAM can be burnt completely in circulated fluidized bed furnaces, and the VAM oxidation does not obviously affect the boiler operation when the methane concentration is less than 0.6%. The VAM decreased the incomplete combustion loss for the circulating fluidized bed combustion furnace. The economic benefit from the coal saving insures that the proposed system is more economically feasible.

  3. Development of Electronic Circulating Pump by Axial Air-gap Type Brush less Motor for Boiler

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Uk; Lee, Chang Eon; Kim, Young Seok; Yim, Chang Soon [Inha University (Korea, Republic of); Kim, Dong Chun [Pyung Taek Technical Junior College (Korea, Republic of); Suh, Sung Won [Bupyung Technical High School (Korea, Republic of)

    1997-04-30

    Canned type household circulating pump in the country almost depends on the act of imports, however it has disadvantage of low efficiency because an air gap of between rotor and stator is large and when the boiler is not used in a period of summer, a can and a rotor become adhered each other. Accordingly the pump is impossible to drive the initial state, and a lifetime of the pump gets shortening. To overcome these defects a electronic circulating pump by axial air-gap type brush less motor which is completely depart from the general idea for the conventional pump is developed. This paper is verified through experiments that the developed pump has good performance for reduction of size and noise, retrenchment of cost, and improvement of efficiency in comparison with the conventional pump. (author). refs., figs., tabs.

  4. Relationship between climate extremes in Romania and their connection to large-scale air circulation

    Science.gov (United States)

    Barbu, Nicu; Ştefan, Sabina

    2015-04-01

    The aim of this paper is to investigate the connection between climate extremes (temperature and precipitation) in Romania and large-scale air circulation. Daily observational data of maximum air temperature and amount of precipitation for the period 1961-2010 were used to compute two seasonal indices associated with temperature and precipitation, quantifying their frequency, as follows: frequency of very warm days (FTmax90 ≥ 90th percentile), frequency of very wet days (FPp90; daily precipitation amount ≥ 90th percentile). Seasonally frequency of circulation types were calculated from daily circulation types determined by using two objective catalogues (GWT - GrossWetter-Typen and WLK - WetterLargenKlassifikation) from the COST733Action. Daily reanalysis data sets (sea level pressure, geopotential height at 925 and 500 hPa, u and v components of wind vector at 700 hPa and precipitable water content for the entire atmospheric column) build up by NCEP/NCAR, with 2.5°/2.5° lat/lon spatial resolution, were used to determine the circulation types. In order to select the optimal domain size related to the FTmax90 and the FPp90, the explained variance (EV) has been used. The EV determines the relation between the variance among circulation types and the total variance of the variable under consideration. This method quantifies the discriminatory power of a classification. The relationships between climate extremes in Romania and large-scale air circulation were investigated by using multiple linear regression model (MLRM), the predictands are FTmax90 and FPp90 and the circulation types were used as predictors. In order to select the independent predictors to build the MLRM the collinearity and multicollinearity analysis were performed. The study period is dividend in two periods: the period 1961-2000 is used to train the MLRM and the period 2001-2010 is used to validate the MLRM. The analytical relationship obtained by using MLRM can be used for future projection

  5. Truss-Integrated Thermoformed Ductwork Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Steven Winter; Dianne Griffiths; Ravi Gorthala

    2007-08-30

    This report summarizes a multi-year research effort to develop a leak-free duct system that can be readily installed within the thermal envelope. There are numerous efforts underway to improve duct system efficiency. Most of these involve modifications to current technology such as air sealing techniques like mastic and aeroseal, snap together duct connections, and greater levels of insulation. This project sought to make a more significant stride forward by introducing a duct system of a material that can be more readily sealed and can exhibit lower friction losses. The research focused on the use of smooth internal surface, low friction plastic ducts that could be easily installed with very low air leakage. The initial system concept that was proposed and researched in Phase I focused on the use of thermoformed plastic ducts installed in a recessed roof truss underneath the attic insulation. A bench top thermoformed system was developed and tested during Phase I of the project. In Phase II, a first generation duct system utilizing a resin impregnated fiberglass duct product was designed and specified. The system was installed and tested in an Atlanta area home. Following this installation research and correspondence with code officials was undertaken to alleviate the continued concern over the code acceptance of plastic ducts in above ground applications. A Committee Interpretation response was received from the International Code Council (ICC) stating that plastic ducts were allowed, but must be manufactured from materials complying with Class 0 or Class 1 rating. With assurance of code acceptance, a plastic duct system using rotomolded high density polyethylene ducts that had passed the material test requirements by impregnating the material with a fire retardant during the molding process was installed in the basement of a new ranch-style home in Madison, WI. A series of measurements to evaluate the performance benefits relative to a similar control house with

  6. Quantifying the effects of mixing and residual circulation on trends of stratospheric mean age of air

    Science.gov (United States)

    Ploeger, Felix; Abalos, Marta; Birner, Thomas; Konopka, Paul; Legras, Bernard; Müller, Rolf; Riese, Martin

    2015-04-01

    Trends in stratospheric mean age of air are driven both by changes in the (slow, large scale) residual mean mass circulation and by changes in (fast, locally acting) eddy mixing. However, to what degree both effects affect mean age trends is an open question. Here, we present a method that allows the effects of mixing and residual circulation on trends of mean age of air to be quantified. This method is based on mean age simulations with the Lagrangian chemistry transport model CLaMS driven by ERA-Interim reanalysis, and on the mean age tracer continuity equation integrated along the residual circulation. CLaMS simulated climatological mean age in the lower stratosphere shows reliable agreement with balloon borne in-situ obsevations and with satellite observations by MIPAS (Michelson Interferometer for Passive Atmospheric Sounding). During 1990--2013, CLaMS simulated mean age decreases throughout most of the stratosphere, qualitatively consistent with results based on climate model simulations (e.g., Butchart et al., 2010). Remarkably, in the Northern hemisphere subtropics and mid-latitudes above about 24km CLaMS mean age trends are insignificant, consistent with published mean age trends from in-situ observations (Engel et al., 2009). Furthermore, during 2002--2012 CLaMS mean age changes show a clear hemispheric asymmetry in agreement with MIPAS satellite observations (Stiller et al., 2012; Ploeger et al., 2014) and HCl decadal changes (Mahieu et al., 2014). We find that changes in the transit time along the residual circulation alone cannot explain the mean age trends, and including the effect of mixing integrated along the air parcel history is essential. Therefore, differences in mean age trends between models or between models and observations are likely related to differences in the integrated effect of mixing on mean age of air. Above about 550K, trends in the integrated mixing effect appear to be likely coupled to residual circulation changes. References

  7. Possible influence of stratospheric circulation on January surface air temperature over China

    Science.gov (United States)

    Tan, Guirong; Zhu, Weijun; Zeng, Gang; Sun, Zhaobo; Peng, Lixia

    2009-08-01

    In terms of monthly NCEP/NCAR and 160 site temperature data from NCC (National Climate Center), the main modes of January surface air temperature in 1979-2008 over China and possible mechanism of typical cold/warm episodes are investigated. Results show that the first mode for January temperature is characterized by consist variation in China, which is closely related to circulation anomalies in stratosphere. From the wave source over East Asian in stratosphere wave fluxes propagate downward and westward, and in upper troposphere over North Atlantic there is a remarkable convergent area of wave flux leading to the ridge enhanced with stronger heat transforming to the North and front zone moving to more northerly. Thereby jet stream becomes strong and expands to East Atlantic with positive (negative) NAO anomaly pattern and higher pressure occurs south to Baikal indicating stronger (weaker) than normal cold air, which is helpful for lower (higher) temperature appearing over China

  8. Zonal-mean circulation response to reduced air-sea momentum roughness

    CERN Document Server

    Polichtchouk, I

    2016-01-01

    The impact of uncertainties in surface layer physics on the atmospheric general circulation is comparatively unexplored. Here the sensitivity of the zonal-mean circulation to reduced air-sea momentum roughness ($Z_{0m}$) at low flow speed is investigated with the Community Atmosphere Model (CAM3). In an aquaplanet framework with prescribed sea surface temperatures, the response to reduced $Z_{0m}$ resembles the La Ni$\\tilde{\\text{n}}$a minus El Ni$\\tilde{\\text{n}}$o response to El Ni$\\tilde{\\text{n}}$o Southern Oscillation variability with: i) a poleward shift of the mid-latitude westerlies extending all the way to the surface; ii) a weak poleward shift of the subtropical descent region; and iii) a weakening of the Hadley circulation, which is generally also accompanied by a poleward shift of the inter-tropical convergence zone (ITCZ) and the tropical surface easterlies. Mechanism-denial experiments show this response to be initiated by the reduction of tropical latent and sensible heat fluxes, effected by re...

  9. Coastal recirculation potential affecting air pollutants in Portugal: The role of circulation weather types

    Science.gov (United States)

    Russo, Ana; Gouveia, Célia; Levy, Ilan; Dayan, Uri; Jerez, Sonia; Mendes, Manuel; Trigo, Ricardo

    2016-06-01

    Coastal zones are under increasing development and experience air pollution episodes regularly. These episodes are often related to peaks in local emissions from industry or transportation, but can also be associated with regional transport from neighbour urban areas influenced by land-sea breeze recirculation. This study intends to analyze the relation between circulation weather patterns, air mass recirculation and pollution levels in three coastal airsheds of Portugal (Lisbon, Porto and Sines) based on the application of an objective quantitative measure of potential recirculation. Although ventilation events have a dominant presence throughout the studied 9-yrs period on all the three airsheds, recirculation and stagnation conditions occur frequently. The association between NO2, SO2 and O3 levels and recirculation potential is evident during summer months. Under high average recirculation potential and high variability, NO2 and SO2 levels are higher for the three airsheds, whilst for O3 each airshed responds differently. This indicates a high heterogeneity among the three airsheds in (1) the type of emission - traffic or industry - prevailing for each contaminant, and (2) the response to the various circulation weather patterns and recirculation situations. Irrespectively of that, the proposed methodology, based on iterative K-means clustering, allows to identify which prevailing patterns are associated with high recirculation potential, having the advantage of being applicable to any geographical location.

  10. Numerical modeling of the thermoelectric cooler with a complementary equation for heat circulation in air gaps

    Science.gov (United States)

    Fang, En; Wu, Xiaojie; Yu, Yuesen; Xiu, Junrui

    2017-01-01

    In this paper, a numerical model is developed by combining thermodynamics with heat transfer theory. Taking inner and external multi-irreversibility into account, it is with a complementary equation for heat circulation in air gaps of a steady cooling system with commercial thermoelectric modules operating in refrigeration mode. With two modes concerned, the equation presents the heat flowing through air gaps which forms heat circulations between both sides of thermoelectric coolers (TECs). In numerical modelling, a TEC is separated as two temperature controlled constant heat flux reservoirs in a thermal resistance network. In order to obtain the parameter values, an experimental apparatus with a commercial thermoelectric cooler was built to characterize the performance of a TEC with heat source and sink assembly. At constant power dissipation, steady temperatures of heat source and both sides of the thermoelectric cooler were compared with those in a standard numerical model. The method displayed that the relationship between Φf and the ratio Φ_{c}'/Φ_{c} was linear as expected. Then, for verifying the accuracy of proposed numerical model, the data in another system were recorded. It is evident that the experimental results are in good agreement with simulation(proposed model) data at different heat transfer rates. The error is small and mainly results from the instabilities of thermal resistances with temperature change and heat flux, heat loss of the device vertical surfaces and measurements.

  11. Availability analysis of thermal power plant boiler air circulation system using Markov approach

    Directory of Open Access Journals (Sweden)

    Ravinder Kumar

    2014-01-01

    Full Text Available The long term operation and planning of power plant depend upon an effective availability analysis and assessment of various systems in the plant concerned. The plant is expected to remain operational in a continual manner to achieve the desired production targets. Hence, the availability analysis of the boiler air circulation system plays an important role in this direction. For this purpose, the concerned system mathematical model based on Markov Birth-Death process has been developed. The system consists of four subsystems. The transition diagram represents reduced capacity, full working and failed state of the system. The differential equations associated with the transition diagram based on probabilistic approach have been solved recursively in order to develop the system steady state availability. Availability matrices represented measures the performance of the system concerned. In addition, different combinations of failures and repair rates provide various availability levels of the system. Maintenance decisions are taken based upon these values for improving availability of the power plant as well as the power supply. The result shows that the failure of the primary air fan affects the system availability at most, while failure of air heater affect it at least for different failures and repair rate combination of subsystems under study.

  12. Shear turbulence, Langmuir circulation and scalar transfer at an air-water interface

    Science.gov (United States)

    Hafsi, Amine; Tejada-Martinez, Andres; Veron, Fabrice

    2016-11-01

    DNS of an initially quiescent coupled air-water interface driven by an air-flow with free stream speed of 5 m/s generates gravity-capillary waves and small-scale (centimeter-scale) Langmuir circulation (LC) beneath the interface. In addition to LC, the waterside turbulence is characterized by shear turbulence with structures similar to classical "wall streaks" in wall-bounded flow. These streaks, denoted here as "shear streaks", consist of downwind-elongated vortices alternating in sign in the crosswind direction. The presence of interfacial waves causes interaction between these vortices giving rise to bigger vortices, namely LC. LES with momentum equation augmented with the Craik-Leibovich (C-L) vortex force is used to understand the roles of the shear streaks (i.e. the shear turbulence) and the LC in determining scalar flux from the airside to the waterside and vertical scalar transport beneath. The C-L force consists of the cross product between the Stokes drift velocity (induced by the interface waves) and the flow vorticity. It is observed that Stokes drift shear intensifies the shear streaks (with respect to flow without wave effects) leading to enhanced scalar flux at the air-water interface. LC leads to increased vertical scalar transport at depths below the interface.

  13. Forced circulation air coolers with internally finned tubes; Ventilator-Luftkuehler mit innenberippten Rohren

    Energy Technology Data Exchange (ETDEWEB)

    Arnemann, M. [Forschungszentrum fuer Kaelte- und Umwelttechnik GmbH (FKU), Berlin (Germany)

    1998-04-01

    Tubes with internal fins have a much higher heat transfer during evaporation as compared with unfinned tubes. The findings served as a basis for the new development of the ``FHV high-performance forced circulation air cooler`` by Walter Roller GmbH and Co. The new evaporator type was designed on the basis of DIN 8955 and ENV 328 for evaporation temperatures of 0 C to -31 C. (orig.) [Deutsch] Im Vergleich zu glatten Rohren laesst sich durch den Einsatz von innenberippten Rohren der innere Waermeuebergang bei der Verdampfung nachweislich deutlich verbessern. Die Ergebnisse bildeten die Grundlage fuer die Neuentwicklung `FHV Hochleistungs-Luftkuehler` im Hause Walter Roller GmbH and Co. Die energetische Bewertung des neuen Verdampfertyps erfolgte in Anlehnung an die Normen DIN 8955 bzw. ENV 328 fuer Verdampfungstemperaturen zwischen 0 C und -31 C. (orig.)

  14. Migration history of air-breathing fishes reveals Neogene atmospheric circulation patterns

    Science.gov (United States)

    Böhme, M.

    2004-05-01

    The migration history of an air-breathing fish group (Channidae; snakehead fishes) is used for reconstructing Neogene Eurasian precipitation and atmospheric circulation patterns. The study shows that snakeheads are sensitive indicators of summer precipitation maxima in subtropical and temperate regions, and are present regularly if the wettest month exceeds 150 mm precipitation and 20 °C mean temperature. The analysis of 515 fossil freshwater fish deposits of the past 50 m.y. from Africa and Eurasia shows two continental-scale migration events from the snakeheads' center of origin in the south Himalayan region, events that can be related to changes in the Northern Hemisphere circulation pattern. The first migration, ca. 17.5 Ma, into western and central Eurasia may have been caused by a northward shift of the Intertropical Convergence Zone that brought western Eurasia under the influence of trade winds that produced a zonal and meridional precipitation gradient in Europe. During the second migration, between 8 and 4 Ma, into Africa and East Asia, snakeheads reached their present-day distribution. This migration could have been related to the intensification of the Asian monsoon that brought summer precipitation to their migratory pathways in East Africa Arabia and East Asia.

  15. Atmospheric circulation in regional climate models over Central Europe: links to surface air temperature and the influence of driving data

    Energy Technology Data Exchange (ETDEWEB)

    Plavcova, Eva [Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic, Prague 4 (Czech Republic); Technical University, Department of Applied Mathematics, Liberec (Czech Republic); Charles University, Faculty of Mathematics and Physics, Prague (Czech Republic); Kysely, Jan [Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic, Prague 4 (Czech Republic); Technical University, Department of Applied Mathematics, Liberec (Czech Republic)

    2012-10-15

    The study examines simulation of atmospheric circulation, represented by circulation indices (flow direction, strength and vorticity), and links between circulation and daily surface air temperatures in regional climate models (RCMs) over Central Europe. We explore control simulations of five high-resolution RCMs from the ENSEMBLES project driven by re-analysis (ERA-40) and the same global climate model (ECHAM5 GCM) plus of one RCM (RCA) driven by different GCMs. The aims are to (1) identify errors in RCM-simulated distributions of circulation indices in individual seasons, (2) identify errors in simulated temperatures under particular circulation indices, and (3) compare performance of individual RCMs with respect to the driving data. Although most of the RCMs qualitatively reflect observed distributions of the airflow indices, each produces distributions significantly different from the observations. General biases include overestimation of the frequency of strong flow days and of strong cyclonic vorticity. Some circulation biases obviously propagate from the driving data. ECHAM5 and all simulations driven by ECHAM5 underestimate frequency of easterly flow, mainly in summer. Except for HIRHAM, however, all RCMs driven by ECHAM5 improve on the driving GCM in simulating atmospheric circulation. The influence on circulation characteristics in the nested RCM differs between GCMs, as demonstrated in a set of RCA simulations with different driving data. The driving data control on circulation in RCA is particularly weak for the BCM GCM, in which case RCA substantially modifies (but does not improve) the circulation from the driving data in both winter and summer. Those RCMs with the most distorted atmospheric circulation are HIRHAM driven by ECHAM5 and RCA driven by BCM. Relatively strong relationships between circulation indices and surface air temperatures were found in the observed data for Central Europe. The links differ by season and are usually stronger for

  16. Air-based coal gasification in a two-chamber gas reactor with circulating fluidized bed

    Science.gov (United States)

    Dubinin, A. M.; Tuponogov, V. G.; Kagramanov, Y. A.

    2017-01-01

    During the bed gasification of solid fuels, the process temperature in the reaction zone is not high enough for reaching the maximum rate of the chemical efficiency factor of the gasification process. In order to increase the chemical efficiency factor, it is necessary to supply extra heat to the reaction zone to increase the reaction temperature. In this article, coal gasification in a chamber with forced fluidized bed is considered and it is proposed to supply extra heat with a circulating flow of an inert particulate heat transfer agent. Circulating inert particulate material is successively heated by coal combustion in a cone chamber with bubbling fluidized bed and in a combustion chamber with a spherical nozzle that inhibits the forced fluidized bed. After that, the heat transfer agent heated to 930-950°C enters first in a gasification chamber with bubbling bed and then in a chamber with forced fluidized bed, where it transfers the physical heat to the air fuel mixture. The experiments conducted with crushed Borodinsky coal and inert particulate heat transfer agent (electrocorundum) showed the temperature rise in a gasification chamber with from 760 to 870°C and the increase in the combustible component (CO) concentration in the gasification products by 5.5%. Based on the kinetic equations of the fuel combustion reactions and the CO2 reduction to CO and on the thermal balance equations of combustion and gasification chambers, the simulation model for the gas composition and the temperature rate calculated by the height of reaction chambers was developed. The experimental temperature rates and product gas compositions are in good agreement with the simulation results based on the proposed kinetic gasification model.

  17. Leaching Behavior of Circulating Fluidised Bed MSWI Air Pollution Control Residue in Washing Process

    Directory of Open Access Journals (Sweden)

    Zhiliang Chen

    2016-09-01

    Full Text Available In this study, air pollution control (APC residue is conducted with water washing process to reduce its chloride content. A novel electrical conductivily (EC measurement method is proposed to monitor the dynamic change of chloride concentrations in leachate as well as the chloride content of the residue. The method equally applies to various washing processes with different washing time, liquid/solid ratio and washing frequency. The results show that washing effectively extracts chloride salts from APC residues, including those from circulating fluidized bed (CFB municipal solid waste incineration (MSWI. The most appropriate liquid/solid ratio and washing time in the first washing are found to be around 4 L water per kg of APC residue and 30 min, respectively, and washing twice is required to obtain maximum dissolution. The pH value is the major controlling factor of the heavy metals speciation in leachate, while chloride concentration also affects the speciation of Cd. Water washing causes no perceptible transfer of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs from the APC residue to leachate. The chloride concentration is strongly related with electrical conductivity (EC, as well as with the concentrations of calcium, sodium and potassium of washing water. Their regression analyses specify that soluble chloride salts and EC could act as an indirect indicator to monitor the change of chloride concentration and remaining chloride content, thus, contributing to the selection of the optimal washing conditions.

  18. Thermal-hydraulic characterization of the natural circulation of air between two vertical cylinders enclosed in a rectangular cavity

    Science.gov (United States)

    Alfredo Payan-Rodriguez, Luis; Rivera-Solorio, Carlos Ivan; Villarreal-Garcia, Salvador; Garcia-Cuellar, Alejadro Javier; Ramirez-Tijerina, Ramon

    2008-11-01

    This work presents the results of an experimental analysis focused on the characterization of the natural circulation of air in the vicinity of two vertical cylinders. A three dimensional cavity encloses each cylinder, where one of them is a heat source and the other is a heat sink. A wall with two holes of variable diameter delimits and connects the two enclosures in order to restrict the air flow exchanged between them. The distance between the center lines of the cylinders was varied with the purpose of measuring the effect of the surrounding walls on the natural circulation. All configurations were tested for different heat generation rates. A Particle Image Velocimeter was used to obtain the flow patterns and a set of thermocouples was installed to measure the temperature field. The experimental results are analyzed and discussed.

  19. Relationships of surface air temperature anomalies over Europe to persistence of atmospheric circulation patterns conducive to heat waves

    Directory of Open Access Journals (Sweden)

    J. Kyselý

    2008-04-01

    Full Text Available Heat waves are among natural hazards with the most severe consequences for human society, including pronounced mortality impacts in mid-latitudes. Recent studies have hypothesized that the enhanced persistence of atmospheric circulation may affect surface climatic extremes, mainly the frequency and severity of heat waves. In this paper we examine relationships between the persistence of the Hess-Brezowsky circulation types conducive to summer heat waves and air temperature anomalies at stations over most of the European continent. We also evaluate differences between temperature anomalies during late and early stages of warm circulation types in all seasons. Results show that more persistent circulation patterns tend to enhance the severity of heat waves and support more pronounced temperature anomalies. Recent sharply rising trends in positive temperature extremes over Europe may be related to the greater persistence of the circulation types, and if similar changes towards enhanced persistence affect other mid-latitudinal regions, analogous consequences and implications for temperature extremes may be expected.

  20. An open reversed Brayton cycle with regeneration using moist air for deep freeze cooled by circulating water

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Shaobo [Guangdong Ocean University, College of Engineering, East Jiefang Rd. No. 40, Xiashan, Zhanjiang, Guangdong 524006 (China); Northwestern Polytechnical University, School of Aeroengine and Thermal Power Engineering, Xi' an, Shaanxi 710072 (China); Zhang, Hefei [Northwestern Polytechnical University, School of Aeroengine and Thermal Power Engineering, Xi' an, Shaanxi 710072 (China)

    2009-01-15

    This paper presents an open reversed Brayton cycle with regeneration using moist air for deep freeze cooled by circulating water, and proves its feasibility through performance simulation. Pinch technology is used to analyze the cooling of the wet air after compressor and the water used for cooling wet air after compressor. Its refrigeration depends mainly on the sensible heat of air and the latent heat of water vapor, its performance is more efficient than a conventional air-cycle, and the utilization of turbo-machinery makes it possible. The adoption of this cycle will make deep freeze easily and reduce initial cost because very low temperature, about -55 C, air is obtained. The sensitivity analysis of coefficient of performance to the efficiency of compressor and the efficiency of compressor, and the results of the cycle are also given. The simulation results show that the COP of this system depends on the temperature before turbine, the efficiency of compressor and the efficiency of compressor, and varies with the wet bulb temperature of the outdoor air. Humid air is a perfect working fluid for deep freeze with no cost to the user. (author)

  1. Studies on the air distribution and thermal performance of the air circulation wall. Part 4. Study on the thermal emissivity of the air circulation layer`s surfaces; Gaidannetsu tsuki koho ni okeru tsuki sonai no netsu tsuki tokusei ni kansuru kenkyu. 4. Tsuki sonai hyomen no hosha tokusei ni kansuru kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kamimori, K.; Sakai, K.; Ishihara, O. [Kumamoto University, Kumamoto (Japan)

    1996-10-27

    The thermal and air distribution characteristics of the air circulation wall in a heat-insulated system were grasped using an experimental model. In this paper, the difference in the heat exchange between the wall and air was confirmed based on the radiation on the circulation layer`s surface. In this system, thin air circulation layers with ventilating holes at the top and bottom are attached to the south and north outer walls of a wooden building. This system is a kind of passive solar house that achieves the insolation screening effect and the temperature rising effect based on solar collection. The heat flow in a circulation layer is eliminated by the natural convection heat transfer on the outer wall. The heat flow passing through insulating materials is the heat transfer by radiation. The heat flow based on the in-layer natural convection is increasingly eliminated by the decrease in temperature on the air circulation layer`s surface. The decrease in room surface temperature using aluminum foil and the reflective heat-insulated effect showed that the heat passing through the wall surface decreases as the convection heat transfer in an air circulation layer increases. 6 refs., 20 figs., 3 tabs.

  2. The impact of circulation patterns on regional transport pathways and air quality over Beijing and its surroundings

    Directory of Open Access Journals (Sweden)

    J. P. Zhang

    2011-12-01

    Full Text Available This study investigated the air pollution characteristics of synoptic-scale circulation in the Beijing megacity, and provided holistic evaluation of the impacts of circulation patterns on air quality during the 2008 Beijing Summer Olympics. Nine weather circulation types (CTs were objectively identified over the North China region during 2000–2009, using obliquely rotated T-mode principal component analysis (PCA. The resulting CTs were examined in relation to the local meteorology, regional transport pathways, and air quality parameters, respectively. The FLEXPART-WRF model was used to calculate 48-h backward plume trajectories for each CT. Nine CTs were characterized, with distinct local meteorology and air mass origins. CT 1 (high to the west with a strong pressure gradient was characterized by a northwestern origin, with the smallest local and southeasterly air mass sources, and CT 6 (high to the northwest had air mass sources mostly from the north and east. In contrast, CTs 5, 8, and 9 (unique, high to the east, and low to the northwest, respectively were characterized by southern and southeastern trajectories, which indicated a greater influence of high pollutant emission sources. In turn, poor air quality in Beijing (high loadings of PM10, BC, SO2, NO2, O3, AOD, and low visibility was associated with these CTs. Good air quality in Beijing was associated with CTs 1 and 6. The average visibilities (with ±1 σ in Beijing for CTs 1 and 6 during 2000–2009 were 18.5 ± 8.3 km and 14.3 ± 8.5 km, respectively. In contrast, poor visibility values of 6.0 ± 3.5 km, 6.6 ± 3.7 km, and 6.7 ± 3.6 km were found in CTs 5, 8, and 9, respectively. The mean concentrations of PM10 for CTs 1, 6, 5, 8, and 9 during 2005–2009 were 90.3 ± 76.3 μg m−3, 111.7 ± 89.6 μg m−3, 173.4 ± 105.8 μg m−3, 158.4 ± 90.0 μg m−3, and 151.2 ± 93.1 μg m

  3. Winter to winter recurrence of atmospheric circulation anomalies over East Asia and its impact on winter surface air temperature anomalies

    Science.gov (United States)

    2017-01-01

    The persistence of atmospheric circulation anomalies over East Asia shows a winter to winter recurrence (WTWR) phenomenon. Seasonal variations in sea level pressure anomalies and surface wind anomalies display significantly different characteristics between WTWR and non-WTWR years. The WTWR years are characterized by the recurrence of both a strong (weak) anomalous Siberian High and an East Asian winter monsoon over two successive winters without persistence through the intervening summer. However, anomalies during the non-WTWR years have the opposite sign between the current and ensuing winters. The WTWR of circulation anomalies contributes to that of surface air temperature anomalies (SATAs), which is useful information for improving seasonal and interannual climate predictions over East Asia and China. In the positive (negative) WTWR years, SATAs are cooler (warmer) over East Asia in two successive winters, but the signs of the SATAs are opposite in the preceding and subsequent winters during the non-WTWR years. PMID:28178351

  4. Ambient particulate air pollution and circulating antioxidant enzymes: A repeated-measure study in healthy adults in Beijing, China.

    Science.gov (United States)

    Wu, Shaowei; Wang, Bin; Yang, Di; Wei, Hongying; Li, Hongyu; Pan, Lu; Huang, Jing; Wang, Xin; Qin, Yu; Zheng, Chanjuan; Shima, Masayuki; Deng, Furong; Guo, Xinbiao

    2016-01-01

    The association of systemic antioxidant activity with ambient air pollution has been unclear. A panel of 40 healthy college students underwent repeated blood collection for 12 occasions under three exposure scenarios before and after relocating from a suburban area to an urban area in Beijing, China in 2010-2011. We measured various air pollutants including fine particles (PM2.5) and determined circulating levels of antioxidant enzymes extracellular superoxide dismutase (EC-SOD) and glutathione peroxidase 1 (GPX1) in the laboratory. An interquartile range increase of 63.4 μg/m(3) at 3-d PM2.5 moving average was associated with a 6.3% (95% CI: 0.6, 12.4) increase in EC-SOD and a 5.5% (95% CI: 1.3, 9.8) increase in GPX1. Several PM2.5 chemical constituents, including negative ions (nitrate and chloride) and metals (e.g., iron and strontium), were consistently associated with increases in EC-SOD and GPX1. Our results support activation of circulating antioxidant enzymes following exposure to particulate air pollution.

  5. Advanced Strategy Guideline. Air Distribution Basics and Duct Design

    Energy Technology Data Exchange (ETDEWEB)

    Arlan Burdick

    2011-12-01

    This report discusses considerations for designing an air distribution system for an energy efficient house that requires less air volume to condition the space. Considering the HVAC system early in the design process will allow adequate space for equipment and ductwork and can result in cost savings.

  6. 78 FR 19606 - Energy Conservation Program for Consumer Products: Test Procedures for Residential Furnace Fans

    Science.gov (United States)

    2013-04-02

    .... Outlet Duct Restriction Specifications 6. Optional Return Air Duct 7. ASHRAE 37-2005 External Static... heating, ventilation, and air-conditioning (HVAC) products to circulate air through ductwork, hereafter... electricity for the purposes of circulating air through ductwork, hereinafter referred to as ``furnace...

  7. Analysis of long-range transport of particulate matters in connection with air circulation over Central and Eastern part of Europe

    Science.gov (United States)

    Stefan, Sabina; Necula, Cristian; Georgescu, Florinela

    The aim of this paper is to establish a practical methodology for examining the long-range transport of particulate matters (PM), named TSP. The daily concentration values of TSP from years 2001 and 2002, for three sites, Baia Mare (RO), Vienna (AU), Aosta (IT), were analyzed. In order to connect the main air circulation types with the aerosol concentrations at the selected sites, the catalogues of Circulation and Weather type Classification (COST733) were used. Spectral analysis was made using spectrum software based on Lomb-Scargle periodograms, and multiresolution analysis (MRA) technique based on Maximal Overlap Discrete Wavelet Transform (MODWT) with Fejer-Korovkin in 22 points wavelet filter (waveslim package). Spectral analysis shows a dominant one-year periodicity for all the time series with a variance around 22% for each time series. In addition, several winters TSP pollution episodes from each city were analyzed using a back trajectory model (HYSPLIT4), in order to compare with the resulted air circulation types. Two important concluding remarks emerge: (i) the Eastern part of Europe shows a dominant easterly air circulation and central Europe is characterized by south-west air circulations, which drive the maxima of pollutant concentrations; (ii) the choice of the domain for analysis of the circulation types is very important.

  8. Seasonal variability of the Caspian Sea three-dimensional circulation, sea level and air-sea interaction

    Directory of Open Access Journals (Sweden)

    R. A. Ibrayev

    2010-03-01

    Full Text Available A three-dimensional primitive equation model including sea ice thermodynamics and air-sea interaction is used to study seasonal circulation and water mass variability in the Caspian Sea under the influence of realistic mass, momentum and heat fluxes. River discharges, precipitation, radiation and wind stress are seasonally specified in the model, based on available data sets. The evaporation rate, sensible and latent heat fluxes at the sea surface are computed interactively through an atmospheric boundary layer sub-model, using the ECMWF-ERA15 re-analysis atmospheric data and model generated sea surface temperature. The model successfully simulates sea-level changes and baroclinic circulation/mixing features with forcing specified for a selected year. The results suggest that the seasonal cycle of wind stress is crucial in producing basin circulation. Seasonal cycle of sea surface currents presents three types: cyclonic gyres in December–January; Eckman south-, south-westward drift in February–July embedded by western and eastern southward coastal currents and transition type in August–November. Western and eastern northward sub-surface coastal currents being a result of coastal local dynamics at the same time play an important role in meridional redistribution of water masses. An important part of the work is the simulation of sea surface topography, yielding verifiable results in terms of sea level. The model successfully reproduces sea level variability for four coastal points, where the observed data are available. Analyses of heat and water budgets confirm climatologic estimates of heat and moisture fluxes at the sea surface. Experiments performed with variations in external forcing suggest a sensitive response of the circulation and the water budget to atmospheric and river forcing.

  9. Seasonal variability of the Caspian Sea three-dimensional circulation, sea level and air-sea interaction

    Directory of Open Access Journals (Sweden)

    R. A. Ibrayev

    2009-09-01

    Full Text Available A three-dimensional primitive equation model including sea ice thermodynamics and air-sea interaction is used to study seasonal circulation and water mass variability in the Caspian Sea under the influence of realistic mass, momentum and heat fluxes. River discharges, precipitation, radiation and wind stress are seasonally specified in the model, based on available data sets. The evaporation rate, sensible and latent heat fluxes at the sea surface are computed interactively through an atmospheric boundary layer sub-model, using the ECMWF-ERA15 re-analysis atmospheric data and model generated sea surface temperature. The model successfully simulates sea-level changes and baroclinic circulation/mixing features with forcing specified for a selected year. The results suggest that the seasonal cycle of wind stress is crucial in producing basin circulation. Seasonal cycle of sea surface currents presents three types: cyclonic gyres in December–January; Eckman south-, south-westward drift in February–July embedded by western and eastern southward coastal currents and transition type in August–November. Western and eastern northward sub-surface coastal currents being a result of coastal local dynamics at the same time play an important role in meridional redistribution of water masses. An important part of the work is the simulation of sea surface topography, yielding verifiable results in terms of sea level. Model successfully reproduces sea level variability for four coastal points, where the observed data are available. Analyses of heat and water budgets confirm climatologic estimates of heat and moisture fluxes at the sea surface. Experiments performed with variations in external forcing suggest a sensitive response of the circulation and the water budget to atmospheric and river forcing.

  10. Impact of Bay-Breeze Circulations on Surface Air Quality and Boundary Layer Export

    Science.gov (United States)

    Loughner, Christopher P.; Tzortziou, Maria; Follette-Cook, Melanie; Pickering, Kenneth E.; Goldberg, Daniel; Satam, Chinmay; Weinheimer, Andrew; Crawford, James H.; Knapp, David J.; Montzka, Denise D.; Diskin, Glenn S.; Dickerson, Russell R.

    2014-01-01

    Meteorological and air-quality model simulations are analyzed alongside observations to investigate the role of the Chesapeake Bay breeze on surface air quality, pollutant transport, and boundary layer venting. A case study was conducted to understand why a particular day was the only one during an 11-day ship-based field campaign on which surface ozone was not elevated in concentration over the Chesapeake Bay relative to the closest upwind site and why high ozone concentrations were observed aloft by in situ aircraft observations. Results show that southerly winds during the overnight and early-morning hours prevented the advection of air pollutants from the Washington, D.C., and Baltimore, Maryland, metropolitan areas over the surface waters of the bay. A strong and prolonged bay breeze developed during the late morning and early afternoon along the western coastline of the bay. The strength and duration of the bay breeze allowed pollutants to converge, resulting in high concentrations locally near the bay-breeze front within the Baltimore metropolitan area, where they were then lofted to the top of the planetary boundary layer (PBL). Near the top of the PBL, these pollutants were horizontally advected to a region with lower PBL heights, resulting in pollution transport out of the boundary layer and into the free troposphere. This elevated layer of air pollution aloft was transported downwind into New England by early the following morning where it likely mixed down to the surface, affecting air quality as the boundary layer grew.

  11. Heat fluxes and roll circulations over the western Gulf Stream during an intense cold-air outbreak

    Science.gov (United States)

    Chou, Shu-Hsien; Ferguson, Michael P.

    1991-01-01

    Turbulence and heat fluxes in the marine atmospheric boundary layer (MABL) for three aircraft stacks near the western Gulf Stream front, observed during the Genesis of Atlantic Lows Experiment (GALE) January 28, 1986 cold-air outbreak, has been studied using mixed-layer scaling. The GOES image and stability parameter indicates that these three stacks were in the roll vortex regime. The turbulence structure in the MABL is studied for this case, as well as the significance of roll vortices to heat fluxes. The roll circulations are shown to contribute significantly to the sensible (temperature) and latent heat (moisture) fluxes with importance increasing upward. The results suggest that the entrainment at the MABL top might affect the the budgets of temperature and humidity fluxes in the lower MABL, but not in the unstable surface layer.

  12. The effect of clear-air turbulence on a model of the general circulation of the atmosphere

    Science.gov (United States)

    Heck, W. J.; Panofsky, H. A.; Bender, M. A.

    1977-01-01

    Mixing coefficients due to clear-air turbulence are estimated from turbulence observations from aircraft, and from large-scale dissipation estimates from the large-scale energy budgets. Maximum coefficients occur near middle-latitude jet streams, and eddy viscosity there is of order of 10 sq m/sec; eddy conductivity is estimated to be about ten times smaller. These coefficients are introduced into the 12-layer general circulation model of the National Center of Atmospheric Research. They produce an apparently significant, though small reduction in maximum speed of the jet, and a reduction in eddy energy. Further, the stratospheric polar-night jet is produced at about the correct location with about the correct intensity.

  13. Testing, adjusting and balancing for air distribution and hydronic circulation system of RIPF

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seon Duk; Bang, H. S

    2003-01-01

    This report is to perform T.A.B(Testing, Adjusting, and Balancing) for area of 7000 and 8000 zone in RIPF Building. According to code, standard and specification, T.A.B of air distribution and hydronic system are carried out and only written a general items. Owing to today's demanding the retrenchment in the energy, It is important that we perform our duties to test, adjust and balance air handle unit objectively and independently. Therefore, though the scientific and reasonable verification procedure, we must try to not only admit T.A.B. techniques which present societies demand, but also secure advanced technologies by means of accelerating the related techniques.

  14. Technical solutions for reducing indoor residential exposures to ultrafine particles from second-hand cigarette smoke infiltration

    DEFF Research Database (Denmark)

    Afshari, Alireza; Ardkapan, Siamak Rahimi; Bergsøe, Niels Christian

    2011-01-01

    was carried out in the field in a multi-storey building and cardboard and plastic foil of polyethylene were used for sealing the entire wooden floor in the receiving flat. Another technical solution examined was a novel air circulating ductwork. The efficiency of the novel air circulating ductwork...

  15. A STUDY ON VARIABILITY OF SEA SURFACE TEMPERATURE IN TROPICAL PACIFIC, INDIAN OCEAN AND RELATED AIR CIRCULATION

    Institute of Scientific and Technical Information of China (English)

    Cui Mao-chang; Qiao Fang-li; Mo Jun

    2003-01-01

    Canonical Correlation Analysis (CCA) was adopted in the present paper to study the of Sea Surface Temperature (SST) in the tropical Pacific, Indian Ocean and related air circulation.The results show that on the seasonal time scale, E1 Nio events can be divided into two types: the east one and the middle one.For the middle type the SST variations appear contrarily in the tropical Pacific and Indian Ocean, and the anomalous SST decreases in the east but increases in the northwest and south-middle of the tropical Indian Ocean, specially in the east of Madagascar Island.And vice versa.On annual time scale, when the Asian continent high gets stronger and the deepened Aleutian low shifts southeastward, both of them trigger an onset of the E1 Nio events.Contrarily, the La Nia events take place.On decadal time scale, there are two basic modes of air-sea system over the tropical Pacific and Indian Ocean.Firstly, when the Asian continent high gets stronger and deepened Aleutian low shifts southeastward, the anomalous SST increases in the middle and east of the proical Pacific, extending to the subtropical regions, and so in most of the tropical Indian Ocean, specially in the northeast of Madagascar Island and nearby.And vice versa.Secondly, when the Asian continent high gets stronger in the north and the Aleutian low decreases fixedly or even disappears, the anomalous SST decreases slightly in middle of the tropical Pacific and the temperate northern Pacific but increases weakly in other regions, the anomalous SST increases in the south but decreases in the north of the tropical Indian Ocean, and the SST increases more obviously in southeast of Madagascar Island.And vice versa.The linear trends of global warming seems to play a certain role for the E1 Nio onsets.

  16. Advanced Strategy Guideline: Air Distribution Basics and Duct Design

    Energy Technology Data Exchange (ETDEWEB)

    Burdick, A.

    2011-12-01

    This report discusses considerations for designing an air distribution system for an energy efficient house that requires less air volume to condition the space. Considering the HVAC system early in the design process will allow adequate space for equipment and ductwork and can result in cost savings. Principles discussed that will maximize occupant comfort include delivery of the proper amount of conditioned air for appropriate temperature mixing and uniformity without drafts, minimization of system noise, the impacts of pressure loss, efficient return air duct design, and supply air outlet placement, as well as duct layout, materials, and sizing.

  17. Seasonal variation of local atmospheric circulations and boundary layer structure in the Beijing-Tianjin-Hebei region and implications for air quality

    Science.gov (United States)

    Miao, Yucong; Hu, Xiao-Ming; Liu, Shuhua; Qian, Tingting; Xue, Ming; Zheng, Yijia; Wang, Shu

    2015-12-01

    The Beijing-Tianjin-Hebei (BTH) region experiences frequent heavy haze pollution in fall and winter. Pollution was often exacerbated by unfavorable atmospheric boundary layer (BL) conditions. The topography in this region impacts the BL processes in complex ways. Such impacts and implications on air quality are not yet clearly understood. The BL processes in all four seasons in BTH are thus investigated in this study using idealized simulations with the WRF-Chem model. Results suggest that seasonal variation of thermal conditions and synoptic patterns significantly modulates BL processes. In fall, with a relatively weak northwesterly synoptic forcing, thermal contrast between the mountains and the plain leads to a prominent mountain-plain breeze circulation (MPC). In the afternoon, the downward branch of the MPC, in addition to northwesterly warm advection, suppresses BL development over the western side of BTH. In the eastern coastal area, a sea-breeze circulation develops late in the morning and intensifies during the afternoon. In summer, southeasterly BL winds allow the see-breeze front to penetrate farther inland (˜150 km from the coast), and the MPC is less prominent. In spring and winter, with strong northwesterly synoptic winds, the sea-breeze circulation is confined in the coastal area, and the MPC is suppressed. The BL height is low in winter due to strong near-surface stability, while BL heights are large in spring due to strong mechanical forcing. The relatively low BL height in fall and winter may have exacerbated the air pollution, thus contributing to the frequent severe haze events in the BTH region.

  18. The using of aeolian energy in air circulators; A utilizacao da energia eolica em circuladores de ar

    Energy Technology Data Exchange (ETDEWEB)

    Assuncao Filho, Telesforo Reis de

    2003-07-01

    The present work is a theoretical research on how to take advantage of the wind kinetic energy using a rotor type Savonius, doing the conversion in mechanical energy, through the fan utilization aiming a thermal comfort and beginning with an introduction on the aeolian energy, its utilization and objectives. Several local types and behavior influenced by the air mass mechanics are shown. A statistic of these air masses and a brief study of the aeolian turbines, its characteristics and design, advantages and disadvantages are presented. An experimental analysis in Sao Luis region were done, using the wind frequency with the objective of obtaining a good revenue. The characterization of the main types of rotors used nowadays are presented, too. (author)

  19. “Clothing from China” from the Philippines to Buenos Aires. Circulation, consumption and corporate struggle, 1580-1620

    Directory of Open Access Journals (Sweden)

    Mariano Bonialian

    2016-11-01

    Full Text Available The paper explores the trade and consumption of Asian fabrics that were distributed from Acapulco to Buenos Aires from 1580 to 1620. Our work with primary sources located in the Archivo de Indias, using viceroys’, governors’ and merchants’ reports, prove that “Ropa de la China” –or clothing from China– was a key element in a trade model that provided an alternative to the official one, with Mexico resisting the economic centralism of Spain.

  20. Gas mixing in a pilot scale (500 KW{sub th}) air blown circulating fluidised bed biomass gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Kersten, S.R.A.; Moonen, R.H.W.; Oosting, T.P. [ECN Biomass, Petten (Netherlands); Prins, W.; Van Swaaij, W.P.M. [Faculty of Chemical Engineering, University of Twente, Enschede (Netherlands)

    2000-07-01

    To study the gas mixing capacity of circulating fluidised bed (CFB) biomass gasifiers, radial and axial gas concentration profiles have been measured and interpreted in both a hot pilot scale biomass gasifier (100 kg/hr fuel) and a cold-flow set-up. The presented data of the pilot scale gasifier are unique and provide new insight in the radial gas mixing capacity of circulating fluidised bed gasifiers. Gas mixing is an important process because the effectiveness of a CFB biomass gasifier, regarding conversion of carbon and tars in the product gas, depends among other things on the degree of reactant mixing. At five different axial positions, in the pilot plant, especially developed probes are installed to withdraw gases from the interior of the reactor. They can be moved freely over the reactor diameter, so full radial profiles can be obtained at each axial position. In the cold-flow set-up similar probes are used to determine radial dispersion coefficients as a function of process variables such as solids flux, gas velocity and additional internals. Considerable radial gas phase concentration gradients have been observed in the pilot plant gasifier, with a difference between wall and centre concentrations up to a factor 3. It must be concluded that the radial gas mixing is far from ideal. On basis of these pilot plant data and a suitable reactor model it can be concluded that the radial Peclet number of the dilute region is in the order of 1000. Such a value excludes the radial mixing of gases almost entirely. Simulations indicate that the occurrence of a parabolic gas velocity profile (also observed in earlier hydrodynamic studies) and a possibly non-uniform biomass distribution, are major causes for steep gradients in the radial gas concentration profiles. From the experiments in the cold-flow set-up it can be concluded that in the dilute region of the riser the radial mixing intensity decreases due to presence of solids. This can be ascribed to a reducing

  1. Fetal Circulation

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Fetal Circulation Updated:Oct 18,2016 click to enlarge The ... fetal heart. These two bypass pathways in the fetal circulation make it possible for most fetuses to survive ...

  2. Analysis of sewage sludge ashes from air and oxy-fuel combustion in a circulating fluidized-bed

    Directory of Open Access Journals (Sweden)

    Magdziarz Aneta

    2016-01-01

    Full Text Available The ashes from sewage sludge combustion in air versus O2/CO2 atmospheres with oxygen concentrations in the range of 21–40% vol. at temperature of 850°C in a 12 kW bench-scale CFB combustor were characterised. The chemical and phase composition of ashes were studied by XRF and XRD. The morphology of studied ashes were examined by SEM method. The slagging and fouling indices were calculated to study the deposition tendencies of ash. The thermal behaviour of ashes was studied by TG-DSC techniques, focusing on the mass loss and thermic effects with the increasing of temperature up to 1200°C.

  3. The air quality in ventilation installations. Practical guidelines; Qualite de l'air dans les installations aerauliques. Guide pratique

    Energy Technology Data Exchange (ETDEWEB)

    Angeli, L. [France Air, 91 - Chilly Mazarin (France); Bianchina, M. [Unelvent, 93 - Le Bourget (France); Blazy, M. [Anjos, 01 - Torcieu (France); Boulanger, X. [Aldes, 21 - Chenove (France); Chiesa, M. [Atlantic (France); Duclos, M. [Groupe Titanair, 69 - Lyon (France); Hubert, D.; Kridorian, O. [Groupe Astato, Blanc Mesnil (France); Josserand, O. [Carrier (Belgium); Lancieux, C. [Camfil, 60 - Saint Martin Longueau (France); Lemaire, J.C. [Agence de l' Environnement et de la Maitrise de l' Energie, ADEME, 75 - Paris (France); Petit, Ph. [Compagnie Industrielle d' Applications Thermiques ( CIAT ), 75 - Paris (France); Ribot, B. [Electricite de France (EDF), 75 - Paris (France); Tokarek, S. [Gaz de France (GDF), 75 - Paris (France); Bernard, A.M.; Tissot, A. [Centre Technique des Industries Aerauliques et Thermiques (CETIAT), 69 - Villeurbanne (France)

    2004-07-01

    The present guide aims to provide design departments, maintenance companies and builders with practical guidelines and recommendations for the installation of ventilation and air-conditioning systems. The objective is to ensure good Indoor Air Quality (IAQ) and to safeguard the health and well-being of the occupants. The guide deals with aspects of design, dimensioning, installation and servicing, all of which play a major role in guaranteeing IAQ and duct-work hygiene. These steps are reviewed for the principal ventilation systems met in both residential and commercial premises. The first part presents the system and draws the attention of the user to specific points which require particular care in term of IAQ. The second part details recommended practice component by component, in respect of design, installation and servicing. Application of these simple guidelines during the various project stages is essential, in order to ensure a good IAQ in ventilation systems. Content: introduction; good ventilation; systems: exhaust ventilation, balanced ventilation, air handling unit, terminal ventilation units, impact of systems on indoor air quality, components: air inlet, air filter, heat recovery unit, heating or cooling coil, humidifier, mechanical fan unit, cowl and hybrid ventilation fan, mixing box, ventilation duct-work, air outlet and air terminal device; references.

  4. Nearshore circulation

    NARCIS (Netherlands)

    Battjes, J.A.; Sobey, R.J.; Stive, M.J.F.

    1990-01-01

    Shelf circulation is driven primarily by wind- and tide-induced forces. It is laterally only weakly constrained so that the geostrophic (Coriolis) acceleration is manifest in the response. Nearshore circulation on the other hand is dominated by wave-induced forces associated with shallow-water. wave

  5. TROPICAL METEOROLOGY & Climate: Hadley Circulation

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jian; Vecchi, Gabriel A.

    2015-01-30

    The Hadley circulation, a prominent circulation feature characterized by rising air near the Equator and sinking air in the subtropics, defines the position of dry subtropical areas and is a fundamental regulator of the earth’s energy and momentum budgets. The character of the Hadley circulation, and its related precipitation regimes, exhibits variation and change in response to both climate variability and radiative forcing changes. The strength and position of the Hadley circulation change from year to year paced by El Niño and La Niña events. Over the last few decades of the twentieth century, the Hadley cell has expanded poleward in both hemispheres, with changes in atmospheric composition (including stratospheric ozone depletion and greenhouse gas increases) thought to have contributed to its expansion. This article introduces the basic phenomenology and driving mechanism of the Hadley circulation and discusses its variations under both natural and anthropogenic climate forcings.

  6. HEPA air filter (image)

    Science.gov (United States)

    ... pet dander and other irritating allergens from the air. Along with other methods to reduce allergens, such ... controlling the amount of allergens circulating in the air. HEPA filters can be found in most air ...

  7. 松软突出煤层水平钻孔反循环气力排屑机理%Chip removal mechanism by air reverse circulation during horizontal drilling in soft outburst coal seam

    Institute of Scientific and Technical Information of China (English)

    韩晓明; 张龙列; 刘瑜; 铁占续

    2015-01-01

    In order to solve the problem of difficult hole-making in gas drainage during bedding drilling process , a new technology of chip removal by air reverse circulation through the drill rod bore during the gas drainage drilling in soft outburst coal seam was put forward .The mathematical model of air reverse circulation conveying on coal cut-tings particles in rod bore was established , and the variation laws of conveying pressure loss and solid phase velocity were analyzed by simulation .The results showed that under the effect of air reverse circulation in the process of bedding horizontal drilling , the air velocity in the upper part of drill rod bore is relatively stable , while in the under part of drill rod bore , the air velocity close to the wall decreases significantly and is less than that in the central zone .In the same location the air velocity becomes greater with the increase of conveying concentration .Under dif-ferent conveying concentration , the pressure loss in the drill rod bore reduces and then increases with the increase of conveying air velocity .There exists a best economic speed in chip removal by air reverse circulation through the drill rod bore .%为了解决顺层钻进瓦斯抽放钻孔成孔难的问题,提出了松软突出煤层瓦斯抽放钻孔钻杆内孔反循环气力排屑新技术,建立煤屑颗粒在钻杆内孔的反循环气力输送数学模型,经仿真求解,分析了输送压力损失及固相速度的变化规律。结果表明,在顺层水平钻孔钻进过程中,煤屑在反循环气力作用下,气流速度在钻杆内孔中上部比较稳定,而在钻杆内孔下部靠近内壁处的气流速度明显下降且小于中心区域;在同一位置输送浓度越大,气流速度也越大;在输送浓度不同的情况下,随着输送气流速度的增加,钻杆内孔的压力损失先降低再增高,在钻杆内孔反循环气力排屑时存在最佳经济速度。

  8. Design and Prototype Test of Hot Air Circulation Molten Plastic Recycling Granulator%热风循环熔融塑料回收造粒机的设计和样机试验

    Institute of Scientific and Technical Information of China (English)

    袁文清; 黄兴元; 王都阳

    2016-01-01

    在分析国内废旧塑料回收现状以及传统塑料回收工艺的基础上,遵循机械设计原理,设计出热风循环熔融废旧塑料回收造粒机,将废旧塑料经热风加热熔融后,再由单螺杆将熔融塑料挤出造粒。其中重点介绍了热风循环熔融塑料系统以及螺杆的几何参数设计。遵循结构设计方案,制造出热风循环熔融塑料回收造粒机的物理样机,并用该样机进行塑料回收试验,试验验证了热风熔融塑料回收的可行性和研究价值,同时针对试验过程中发现的问题提出了一系列解决方法,为后续的改进和进一步研究工作提供了可靠依据。%Based on the analysis of the domestic current situation of the waste plastics recycling and on the basis of traditional plastic recycling technology,following the principleof mechanical design,a molten waste plastic recycling granulator with hot air circulation was designed. The waste plastic was heated and melted by the hot air,and then the molten plastic was extruded and granulated by a single screw. The hot air circulation system and geometric parameters design of the screw were focused on. Follow-ing the structure design project,the physical prototype of hot air circulation molten plastic recycling granulator was produced,and a test of plastic recycling with the prototype was conducted. The test verified the feasibility and research value of hot air molten plastic recycling. At the same time,a series of solutions to the problems found in the test were put forward,which provides the reliable basis for the subsequent improvement work and further research.

  9. 大直径气举反循环成套钻具的研制%Development of Complete Set of Large Diameter Air-lift Reverse Circulation Drilling Tool

    Institute of Scientific and Technical Information of China (English)

    袁志坚

    2014-01-01

    The paper introduces a complete set of large diameter air-lift reverse circulation drilling tool about its develop-ment background, design principle, structure dimensions and main technical parameters.This set of drilling tool, designed by interflush, has the advantages of great intensity and convenient connection, and the section area of tubes for ventilation, mud transfortation and mud recharge are fully considered, it can meet the needs of air-lift reverse circulation drilling for large diameter engineering well.%介绍了大直径气举反循环成套钻具的研制背景、设计原则、结构尺寸和主要技术参数。该套钻具不仅强度大,连接便捷,而且充分考虑了通气、通泥浆、泥浆补给三大通道面积等因素,采用内平设计。经生产试验,完全能满足大直径工程井气举反循环钻进的需要。

  10. Study on the air-lift circulation technique for water-well drilling in karst leaking stratum%岩溶漏失层气助正循环水井钻探新技术的研究

    Institute of Scientific and Technical Information of China (English)

    宋志彬; 张金昌; 许刘万

    2012-01-01

    气助正循环水井钻探新技术主要适用于以岩溶地层为特征的严重漏失地层.该技术通过在双壁钻具的内外管之间泵入压缩空气,举升在钻具与孔壁之间的“环空”形成的空气泥浆.“环空”的气举加速作用阻碍了钻井循环液在地层方向的漏失,并且加速了钻屑的上返速度.该技术的优点在北京房山区岩溶漏失地层的600m水井钻探生产试验中得到了证实.试验结果表明,利用该技术可使泥浆正循环中因严重漏失造成的循环液中断得以恢复,“环空气举作用”大幅度提高了上返的泥浆流量.经对比试验证明,气助正循环工艺在岩溶漏失层的钻进速度高于气举反循环和泥浆正循环,是解决岩溶漏失层钻井液循环中断、钻头烧钻、埋钻等钻探事故的有效方法.%This technique is mainly concerned with a new study of water-well drilling method, which is well applied in severe leakage stratum, especially in karst stratum. Unlike other drilling method, air-lift drilling technique applies the compressed air through the dual wall drilling pipe, lifting the air-mud in annular space between the outer pipe and the wall of hole. The accelerated air-mud speeds up the circulating mud to reduce the leakage capacity and lift cuttings rapidly. Several advantages of this drilling technique were found in the fieldwork research which undertook in the 600 m water well drilling in Fangshan, Beijing. The fieldwork research mainly carried out by the experiment of air-lift drilling tools revealed that the broken circulation of drilling mud had been recovered and the flow of the return mud had been largely improved. The drilling speed of this technique is quicker than the air-lift reverse circulation or the mud drilling method. In severe-leakage stratum, this technique has been proved to be efficient in solve drilling problems, such as broken circulation and burned drill bit. Further study of air-lift drilling method

  11. Improvement of emissions and performance by using of air jet, exhaust gas re-circulation and insulation methods in a direct injection diesel engine

    Directory of Open Access Journals (Sweden)

    Jafarmadara S.

    2013-01-01

    Full Text Available This article investigates the improvement of operation characteristics and emissions reduction by means of creating an air-cell inside the piston body, exhaust gases recirculating and insulating combustion chamber in a direct injection diesel engine simultaneously. The engine considered is a caterpillar 3401 which was modeled with an air-cell included as part of the piston geometry. This air-cell demonstrates that air injection in late combustion period can be effective in a significant reduction of Soot emission while cold EGR can be effective in reduction of NOx emission. Also for increasing of performance parameters, combustion chamber with air-cell is insulated. The analyses are carried out at part (75% of full load and full load conditions at the same engine speed 1600 rpm. The obtained results indicate that creating the air-cell has a slight effect on improvement of performance parameters and it has significantly effect on Soot reduction. The air-cell decreases the Soot pollutant as a factor of two at both part and full load conditions. Also, the adding 5% of cold EGR in inlet air decreases NOx by about half and insulating the engine increases the power and IMEP by about 7.7% and 8.5% and decreases the ISFC by about 7.5% at part load and increases power and IMEP by 8.5%, 8.5% and decreases ISFC by 8% at full load condition, respectively. Using this method, it was possible to control emissions formation and increase performance parameters simultaneously. The predicted results for mean in-cylinder pressure and emissions are compared to the corresponding experimental results and show good agreements.

  12. Circulation economics

    DEFF Research Database (Denmark)

    Ingebrigtsen, Stig; Jakobsen, Ove

    2006-01-01

    Purpose - This paper is an attempt to advance the critical discussion regarding environmental and societal responsibility in economics and business. Design/methodology/approach - The paper presents and discusses as a holistic, organic perspective enabling innovative solutions to challenges...... concerning the responsible and efficient use of natural resources and the constructive interplay with culture. To reach the goal of sustainable development, the paper argues that it is necessary to make changes in several dimensions in mainstream economics. This change of perspective is called a turn towards...... presupposes a perspective integrating economic, natural and cultural values. Third, to organize the interplay between all stakeholders we introduce an arena for communicative cooperation. Originality/value - The paper concludes that circulation economics presupposes a change in paradigm, from a mechanistic...

  13. 空气反循环钻头井底流场分析及结构优化%Analysis on the Bottomhole Flow Field and Structural Optimization of Air Reverse Circulation Drill Bit

    Institute of Scientific and Technical Information of China (English)

    甘心; 殷琨; 殷其雷; 李鹏

    2016-01-01

    In order to improve the application effect of the reverse circulation air hammer drilling technique,on the construction of rock-socketed pile by using software Fluent,the authors analyzed the horizontal inclination angleθd of flushing nozzles and horizontal inclination angleθk of pressure-restoring grooves on the reverse circulation drill bit used in the construction of rock-socketed pile.The effects of theθd of flushing nozzles and theθk of pressure-restoring grooves on the suction coefficient ω of reverse circulation drill bit are obtained.Meanwhile,aiming at the deficiency in the structure design of central hollow-through hole on the reverse circulation drill bit,we optimized the structure of reverse circulation drill bit;and thereby,the suction capacity is obviously enhanced.A 660 mm reverse circulation drill bit adopted to the optimized structure is processed,and the field tests are carried out.It can be concluded from the test results that the effect of reverse circulation formation is good,the average penetration rate is 6.00 m/h, the surface of weakly weathered rocks is successfully drilled out. This meets the requirements on drilling out the surface of weakly weathered rocks and stability of borehole wall without borehole collapse.%为改善空气潜孔锤反循环钻进技术在大口径嵌岩桩施工中的应用效果,运用 Fluent 软件对嵌岩桩施工用反循环钻头底喷孔水平倾角θd 和扩压槽水平倾角θk 做了进一步的分析和研究,得到θd 和θk 对反循环钻头抽吸系数ω的影响规律。在分析中发现原有反循环钻头中心贯通孔结构设计中的不足之处,并进行了优化,优化后的反循环钻头抽吸效果明显增强。采用优化后的结构加工了一个直径为660 mm 的反循环钻头,并进行现场钻进试验,试验效果良好,平均钻进效率为6.00 m/h,成功嵌入微风化岩层表面,能够满足嵌岩桩施工对嵌入微风化岩层和孔壁稳定、无塌孔的要求。

  14. Energy-saving Technical Reconstruction about Circulating Water of Cooling Air Machine in Refinery Plant%炼油厂循环水冷却风机节能技术改造

    Institute of Scientific and Technical Information of China (English)

    周毅

    2011-01-01

    At present,the electric air machines are used in circulating water cooling tower in many refinery plants,where the backwater lift is generally high.Combining the energy-saving technical example about CNOOC Ningbo Daxie/Zhoushan Petrochemical LTD's second reconstruction of cooling air machine,the energy-saving effect of cooling water machine was evaluated,and the developing significance in refinery plants was also analyzed.%针对目前国内大多数炼油企业循环水冷却塔均按电动风机进行设计,普遍存在回水扬程偏大的现象。结合中海石油宁波大榭/舟山石化有限公司二套循环水冷却风机节能改造的应用实例,评价了水动冷却风机的节能效果,并分析了其在炼油企业推广的意义。

  15. 浸泡-风干循环作用对砂岩变形及破坏特征影响研究%Influence of immersion-air dry circulation function on deformation and fracture features of sandstone

    Institute of Scientific and Technical Information of China (English)

    邓华锋; 李建林; 刘杰; 朱敏; 罗骞; 原先凡

    2012-01-01

    In the process of impoundment and normal operation of reservoirs, the water level will rise and fall periodically in a planned way. As a result, the immersion-air dry function will lead to the degeneration of mechanical properties of rock mass in variable amplitude zone with time, and then affect the slope stability. Based on these, the immersion-air dry circulation function tests considering the change of water pressure of sand rock are designed, and the deformation and fracture features of rock samples are studied. The test results indicate that the rise or decline of water pressure and the immersion-air dry circulation function have cumulative and irreversible damage to the samples. In the process of circulation, the stress-strain curves of the sand rock samples become slow gradually, the compaction segment gradually becomes long, the gradient of the elastic deformation section decreases gradually, elastic modulus reduces gradually, yield step gradually becomes long, the axial strain corresponding to the peak intensity increases gradually, and the fracture angle of the samples decreases gradually. The stress-strain curves of the sand rock samples show that the samples have a distinct trend of softening. Moreover, the more the cycle times of the immersion-air dry, the more the serious damage to the rock mass. The results of important reference value in the studies on the deformation and fracture laws of the variable amplitude rock in reservoir banks will provide a favorable evidence for the long-term stability analysis of reservoir bank slopes.%水库正常运营后,库水位将按计划周期性的上升或下降,浸泡-风干循环作用将导致库岸边坡变幅带岩体性质逐渐劣化,进而影响库岸边坡的稳定性,基于此,设计了考虑水压力升、降变化的砂岩浸泡-风干循环作用试验,重点研究了砂岩试样的变形及破坏特征。研究结果表明:水压力升、降变化和浸泡-风干循环作用对岩

  16. Code-to-code comparison for analysing the steady-state heat transfer and natural circulation in an air-cooled RCCS using GAMMA+ and Flownex

    Energy Technology Data Exchange (ETDEWEB)

    Rousseau, P.G., E-mail: pgr@mtechindustrial.com [School of Mechanical and Nuclear Engineering, North-West University, Private Bag X 6001, Potchefstroom (South Africa); Toit, C.G. du [School of Mechanical and Nuclear Engineering, North-West University, Private Bag X 6001, Potchefstroom (South Africa); Jun, J.S.; Noh, J.M. [Korea Atomic Energy Research Institute, Daedeok-daero 989-111, Yuseong-gu, Daejeon (Korea, Republic of)

    2015-09-15

    Highlights: • The GAMMA+ and Flownex codes are used in the analyses of the air-cooled RCCS system. • Radiation heat transfer comprises the bulk of the total rate of heat transfer. • It is possible to obtain reverse flow through the RCCS standpipes. • It has been found that the results obtained with the two codes are in good agreement. • RCCS remain functional for very high blockage ratios thus supporting the safety case. - Abstract: The GAMMA+ and Flownex codes are both based on a one-dimensional flow network modelling approach and both can account for any complex network of different heat transfer phenomena occurring simultaneously. However, there are notable differences in some of the detail modelling aspects, such as the way in which the convection in the reactor cavity is represented. Despite this, it was found in the analyses of the air-cooled RCCS system that the results provided by the two codes compare very well if similar input values are used for the pressure drop coefficients, heat transfer coefficients and view factors. The results show that the radiation heat transfer comprises the bulk of the total rate of heat transfer from the RPV surface. It is also shown that it is possible to obtain a stable and sustainable steady-state operational condition where the flow is in the reverse direction through the RCCS standpipes, resulting in excessively high values for the concrete wall temperature. It is therefore crucial in the design to ensure that such a flow reversal will not occur under any circumstances. In general the good comparison between the two codes provides confidence in the ability of both to correctly solve the fundamental conservation and heat transfer relations in an integrated manner for the complete RCCS system. Provided that appropriate input values are available, these codes can therefore be used effectively to evaluate the integrated performance of the system under various operating conditions. It is shown here that the RCCS

  17. Assessing the radiative impacts of precipitating clouds on winter surface air temperatures and land surface properties in general circulation models using observations

    Science.gov (United States)

    Li, J.-L. F.; Lee, Wei-Liang; Wang, Yi-Hui; Richardson, Mark; Yu, Jia-Yuh; Suhas, E.; Fetzer, Eric; Lo, Min-Hui; Yue, Qing

    2016-10-01

    Using CloudSat-CALIPSO ice water, cloud fraction, and radiation; Clouds and the Earth's Radiant Energy System (CERES) radiation; and long-term station-measured surface air temperature (SAT), we identified a substantial underestimation of the total ice water path, total cloud fraction, land surface radiative flux, land surface temperature (LST), and SAT during Northern Hemisphere winter in Coupled Model Intercomparison Project Phase 5 (CMIP5) models. We perform sensitivity experiments with the National Center for Atmospheric Research (NCAR) Community Earth System Model version 1 (CESM1) in fully coupled modes to identify processes driving these biases. We found that biases in land surface properties are associated with the exclusion of downwelling longwave heating from precipitating ice during Northern Hemisphere winter. The land surface temperature biases introduced by the exclusion of precipitating ice radiative effects in CESM1 and CMIP5 both spatially correlate with winter biases over Eurasia and North America. The underestimated precipitating ice radiative effect leads to colder LST, associated surface energy-budget adjustments, and cooler SAT. This bias also shifts regional soil moisture state from liquid to frozen, increases snow cover, and depresses evapotranspiration (ET) and total leaf area index in Northern Hemisphere winter. The inclusion of the precipitating ice radiative effects largely reduces the model biases of surface radiative fluxes (more than 15 W m-2), SAT (up to 2-4 K), and snow cover and ET (25-30%), compared with those without snow-radiative effects.

  18. 网带式热风循环电热比萨炉的设计和研制%Design and Development of Net Belt Type Hot Air Circulation Electric Pizza Oven

    Institute of Scientific and Technical Information of China (English)

    汤锦添

    2013-01-01

    重点阐述了网带式热风循环电热比萨炉的工作原理和烘烤过程、结构设计和控制系统设计,以及对差异性结构设计的可行性分析;并通过研发试产后,提出功能扩展的设想,探讨遂道式万能蒸烤炉的初步设计方案,可以通过增加蒸气加湿功能来扩大比萨炉的适用范围。%This article focuses on the working principle and baking process with hot air circulation electric pizza oven , structure design and control system design , and the feasibility of different structure design analy-sis;and through research and development production , put forward the idea of functional expansion , tunnel type universal steam oven preliminary design scheme , To expand the scope of pizza oven by increasing the steam humidification function .

  19. 非能动安全壳冷却系统空气流道自然循环的比例分析与设计%Scaling Analysis and Design for PCS Air Flow Path Natural Circulation

    Institute of Scientific and Technical Information of China (English)

    刘卓; 常华健; 阳祥; 杨燕宁

    2016-01-01

    在考虑建设试验台架经济性的前提下,缩小比例的单项和整体效应试验台架对研究和开发大型先进压水堆核电站及其分析验证程序都具有重要意义。非能动安全壳冷却系统(PCS )壳外空气流道内的自然循环在安全壳非能动冷却性能中发挥着重要的作用。本文从自然循环的数学模型出发,推导出了单项和整体效应试验台架的比例设计方法。在给定壳内热流密度的条件下,通过PCCSAP‐3D程序对C A P1400非能动安全壳的2/5比例单项效应试验理想比例台架(IS F )进行模拟。结果表明,本比例分析与设计方法以及在降低高度台架上模拟自然循环是可行的。%The scale‐down separate and integral effect test facilities are of vital signifi‐cance not only for the research and development of large‐scale advanced pressurized w ater reactor nuclear pow er plants ,but also for validation and verification of the related analysis codes . The passive containment cooling system (PCS ) air flow path system plays an important role in containment passive cooling .Based on the natural circulation model ,the scaling and design methods for both the separate and integral effect test facil‐ities were proposed .Under given heat flux from the inner side of the shell ,simulation of an ideal scaled facility (ISF) design of a 2/5 length scaled separate effect test facility for CAP1400 PCS was preliminarily performed by the PCCSAP‐3D code .The simulation results show that the design method and the modeling of natural circulation on a reduced height test facility are feasible .

  20. Cooling and Heating Season Impacts of Right-Sizing of Fixed- and Variable-Capacity Heat Pumps With Attic and Indoor Ductwork

    Energy Technology Data Exchange (ETDEWEB)

    Cummings, James [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States); Withers, Charles [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States); Kono, Jamie [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States)

    2015-06-24

    A new generation of full variable-capacity air-conditioning (A/C) and heat pump units has come on the market that promises to deliver very high cooling and heating efficiency. The units are controlled differently than standard single-capacity (fixed-capacity) systems. Instead of cycling on at full capacity and cycling off when the thermostat is satisfied, the new units can vary their capacity over a wide range (approximately 40%–118% of nominal full capacity) and stay on for 60%–100% more hours per day than the fixed-capacity systems depending on load-to-capacity ratios. Two-stage systems were not evaluated in this research effort.

  1. Microwave circulator design

    CERN Document Server

    Linkhart, Douglas K

    2014-01-01

    Circulator design has advanced significantly since the first edition of this book was published 25 years ago. The objective of this second edition is to present theory, information, and design procedures that will enable microwave engineers and technicians to design and build circulators successfully. This resource contains a discussion of the various units used in the circulator design computations, as well as covers the theory of operation. This book presents numerous applications, giving microwave engineers new ideas about how to solve problems using circulators. Design examples are provided, which demonstrate how to apply the information to real-world design tasks.

  2. Circulation control STOL aircraft design aspects

    Science.gov (United States)

    Loth, John L.

    1987-01-01

    Since Davidson patented Circulation Control Airfoils in 1960, there have been only 2 aircraft designed and flown with circulation control (CC). Designing with CC is complex for the following reasons: the relation between lift increase and blowing momentum is nonlinear; for good cruise performance one must change the wing geometry in flight from a round to a sharp trailing edge. The bleed air from the propulsion engines or an auxiliary compressor, must be used efficiently. In designing with CC, the propulsion and control aspects are just as important as aerodynamics. These design aspects were examined and linearized equations are presented in order to facilitate a preliminary analysis of the performance potential of CC. The thrust and lift requirements for takeoff make the calculated runway length very sensitive to the bleed air ratio. Thrust vectoring improves performance and can offset nose down pitching moments. The choice of blowing jet to free stream velocity ratio determines the efficiency of applying bleed air power.

  3. 太阳能集热器的热流气体对砾石的蓄放热特性研究%Characteristics of heat storage and release of gravel layer in solar collectors by hot air natural circulation

    Institute of Scientific and Technical Information of China (English)

    张文基

    2005-01-01

    The thermal characteristics of heat storage and release of the gravel layer used in the solar collector in winter were analyzed. Air from the solar collector was expected to circulate through the gravel layer naturally without other energy consumption. The gravel layer consisted of river gravels with diameter from 50 mm to 100 mm. The temperature of the solar collector, gravel layer and cement mortar surface were measured respectively to analyze thermal characteristics of heat storage during daytime and heat release at night in the gravel layer. The horizontal and vertical heat characteristics of the gravel layer and cement mortar surface were analyzed. Results of the thermal characteristics of the gravel layer in the solar collector can be used as basic data for the thermal analysis of gravel layer.%太阳能的蓄放热特性的研究对清洁能源太阳能的开发和利用具有重要意义.该文利用冬季太阳能集热器的热流气体,对砾石的蓄放热特性进行了研究.以居民居住的标准房间(4 m×2.7 m)为依据进行了模拟;利用太阳能集热器的热能与直径为50~100 mm的砾石铺设成150 mm厚度的地下蓄热系统进行蓄热和放热试验,研究昼夜之间室内砾石的蓄热和放热特性;通过测试太阳能集热器的内部温度、砾石层内部及室内地表面的温度,研究了太阳能集热器的蓄热效率和转换效率,同时分析了蓄热层及室内地表面的热传递特性;为进一步开拓针对冬季寒冷地区太阳能蓄热型居民建筑物内部热环境方面的基础研究提供了科学的依据.

  4. Mountains and Tropical Circulation

    Science.gov (United States)

    Naiman, Z.; Goodman, P. J.; Krasting, J. P.; Malyshev, S.; Russell, J. L.; Stouffer, R. J.

    2015-12-01

    Observed tropical convection exhibits zonal asymmetries that strongly influence spatial precipitation patterns. The drivers of changes to this zonally-asymmetric Walker circulation on decadal and longer timescales have been the focus of significant recent research. Here we use two state-of-the-art earth system models to explore the impact of earth's mountains on the Walker circulation. When all land-surface topography is removed, the Walker circulation weakens by 33-59%. There is a ~30% decrease in global, large-scale upward vertical wind velocities in the middle of the troposphere, but only minor changes in global average convective mass flux, precipitation, surface and sea-surface temperatures. The zonally symmetric Hadley circulation is also largely unchanged. Following the spatial pattern of changes to large-scale vertical wind velocities, precipitation becomes less focused over the tropics. The weakening of the Walker circulation, but not the Hadley circulation, is similar to the behavior of climate models during radiative forcing experiments: in our simulations, the weakening is associated with changes in vertical wind velocities, rather than the hydrologic cycle. These results indicate suggest that mountain heights may significantly influence the Walker circulation on geologic time scales, and observed changes in tropical precipitation over millions of years may have been forced by changes in tropical orography.

  5. Sensitivity of the Meridional Overturning Circulation to the Pattern of the Surface Density Flux

    Science.gov (United States)

    2010-09-01

    a better prognosis of anthropogenic climate change . Figure 1. Classical representation of the global thermohaline circulation and oceanic...modeling efforts and long-term strategy related to climate change . 15. NUMBER OF PAGES 105 14. SUBJECT TERMS Meridional Overturning Circulation ... Thermohaline Circulation , Thermocline, Residual-Mean Theory, Air-Sea Fluxes, Surface Density Flux , Mixed-Layer Density, Water-mass Transformation

  6. Learning Circulant Sensing Kernels

    Science.gov (United States)

    2014-03-01

    learned dictionaries. Examples of analytic dictionaries include the discrete cosine basis, various wavelets bases , as well as tight frames. Some of them...Compressive sensing based high resolution channel estimation for OFDM system. To appear in IEEE Journal of Selected Topics in Signal Processing, Special...theoretical and computational properties to a (partial) circulant matrix of the same size, our discussions below are based exclusively on the circulant

  7. Effect of Air Cleaning Technologies in Conjunction With the Use of Rotary Heat Exchangers in Residential Buildings

    DEFF Research Database (Denmark)

    Afshari, Alireza; Bergsøe, Niels Christian; Ekberg, Lars

    2013-01-01

    with rotary air-to-air heat exchangers. For this purpose, a mechanical filter with low pressure drop and a 4 cm thick activated carbon filter were selected for testing in a laboratory environment. The measurements included testing of the filters, separately and combined, in a ductwork to study the efficiency...... of the filters. The removal efficiency of the mechanical filter for ultrafine particles was examined using burning candles as sources for emission of particles. The measurements in the duct showed that the efficiency of the particle filter ranged between approximately 50% and 80% and the pressure loss...... of gases. The measurement results showed that the efficiency of the combined filters ranged between approximately 30% and 80% and the pressure loss was less than approximately 20 Pascal at an airflow rate of 250 m3/h....

  8. Gaussian Fibonacci Circulant Type Matrices

    Directory of Open Access Journals (Sweden)

    Zhaolin Jiang

    2014-01-01

    Full Text Available Circulant matrices have become important tools in solving integrable system, Hamiltonian structure, and integral equations. In this paper, we prove that Gaussian Fibonacci circulant type matrices are invertible matrices for n>2 and give the explicit determinants and the inverse matrices. Furthermore, the upper bounds for the spread on Gaussian Fibonacci circulant and left circulant matrices are presented, respectively.

  9. Combining active chilled beams and air-cleaning technologies to improve the indoor climate in offices

    DEFF Research Database (Denmark)

    Ardkapan, Siamak Rahimi; Afshari, Alireza; Bergsøe, Niels Christian

    2013-01-01

    of air in offices. For this purpose, a mechanical filter with low pressure drop was selected for testing in a laboratory environment. The measurements included tests of the filter in a ductwork to study the efficiency of the filter. Moreover, the combined system of the filter and a chilled beam...... was tested in a room. The efficiency of the mechanical filter to remove ultrafine particles was examined using pure wax candles and salt as sources of emission of particles. The measurements in the duct showed that the efficiency of the filter ranged between 54% and 78% and that the pressure loss was less...... than 5 Pa (0.104 Ibf /ft2). Furthermore, the measurement results of the combined system showed that adding the filter accelerated the removal rate of the particles by 2 h-1. However, the efficiency of the chilled beam in exchanging heat was reduced by 38%....

  10. Circulant Double Coverings of a Circulant Graph of Valency Five

    Institute of Scientific and Technical Information of China (English)

    Rong Quan FENG; Jin Ho KWAK

    2007-01-01

    Enumerating the isomorphism classes of several types of graph covering projections is one of the central research topics in enumerative topological graph theory. A covering of G is called circulant if its covering graph is circulant. Recently, the authors [Discrete Math., 277, 73-85 (2004)]enumerated the isomorphism classes of circulant double coverings of a certain type, called a typicalcovering, and showed that no double covering of a circulant graph of valency three is circulant. Also, in [Graphs and Combinatorics, 21, 386-400 (2005)], the isomorphism classes of circulant double coverings of a circulant graph of valency four are enumerated. In this paper, the isomorphism classes of circulant double coverings of a circulant graph of valency five are enumerated.

  11. Kernels in circulant digraphs

    Directory of Open Access Journals (Sweden)

    R. Lakshmi

    2014-06-01

    Full Text Available A kernel $J$ of a digraph $D$ is an independent set of vertices of $D$ such that for every vertex $w,in,V(D,setminus,J$ there exists an arc from $w$ to a vertex in $J.$ In this paper, among other results, a characterization of $2$-regular circulant digraph having a kernel is obtained. This characterization is a partial solution to the following problem: Characterize circulant digraphs which have kernels; it appeared in the book {it Digraphs - theory, algorithms and applications}, Second Edition, Springer-Verlag, 2009, by J. Bang-Jensen and G. Gutin.

  12. The Study of the Legionella pneumophila Pollution and Killing Effects on Centralized Air-conditioners Cooling Circulating Water in Huizhou City%惠州市中央空调冷却循环水中嗜肺军团菌污染状况和杀灭效果观察

    Institute of Scientific and Technical Information of China (English)

    郑惠东; 杨建秀; 郑丽萍; 戴昌芳; 辜少红; 严琦瑞; 柯晓明

    2012-01-01

    Objective To understand the Legionella pneumophila pollution and the effects of killing Legionella pneumophila by electrolyzed water of Centralized Air Ventilation System in Huizhou City.Methods We culture and identify 123 units Legionella pneumophila,which collecting in the Centralized Air-conditioners cooling circulation water of Huizhou.A new type of low-voltage high-frequency electrolytic water equipment is applied by Guang Zhou Shui Li Qing Environmental Protection Technology Co.,Ltd.It can use physical way instead of chemicals to deal with Legionella pneumophila and other pathogenic microorganisms in cooling circulating water in centralized air-conditioners.Results In the survey of 123 units,448 water samples were collected,313 samples were prove out that contain Legionella pneumophila,the detection rate is 69.86%.At the same time,62 units which contain Legionella pneumophila were collected from Centralized Air-conditioners and deal with low voltage high frequency Electrolyzed Water equipment for 7-73 d.Finally,112 water samples,which from those units,were found out that all the Legionella pneumophila had been killed.The sterilizing rate for the Legionella pneumophila is 100%.Conclusion Part of Centralized Air-conditioners Cooling Circulating Water were Pollution by Legionella pneumophila in Huizhou,Daily inspection should be taken,The low-voltage high-frequency electrolytic water equipment can effectively control and sterilize Legionella pneumophila etc in the cooling water and chilled water in centralized air-conditioners.It has a good application prospect for this technology.%目的 了解惠州市中央空调冷却循环水中嗜肺军团菌污染情况和电解水对其的杀灭效果观察.方法 对惠州市123个单位中央空调冷却循环水进行嗜肺军团菌的培养和鉴定;然后采用源自广州水力清环保科技有限公司的新型低压高频电解水处理器,用物理方式代替化学药剂,处理中央空调冷却循环水

  13. The fetal circulation.

    Science.gov (United States)

    Kiserud, Torvid; Acharya, Ganesh

    2004-12-30

    Accumulating data on the human fetal circulation shows the similarity to the experimental animal physiology, but with important differences. The human fetus seems to circulate less blood through the placenta, shunt less through the ductus venosus and foramen ovale, but direct more blood through the lungs than the fetal sheep. However, there are substantial individual variations and the pattern changes with gestational age. The normalised umbilical blood flow decreases with gestational age, and, at 28 to 32 weeks, a new level of development seems to be reached. At this stage, the shunting through the ductus venosus and the foramen ovale reaches a minimum, and the flow through the lungs a maximum. The ductus venosus and foramen ovale are functionally closely related and represent an important distributional unit for the venous return. The left portal branch represents a venous watershed, and, similarly, the isthmus aorta an arterial watershed. Thus, the fetal central circulation is a very flexible and adaptive circulatory system. The responses to increased afterload, hypoxaemia and acidaemia in the human fetus are equivalent to those found in animal studies: increased ductus venosus and foramen ovale shunting, increased impedance in the lungs, reduced impedance in the brain, increasingly reversed flow in the aortic isthmus and a more prominent coronary blood flow.

  14. 46 CFR 153.314 - Ventilation of spaces not usually occupied.

    Science.gov (United States)

    2010-10-01

    ... this section; and (2) Either permanent ventilation ductwork connected to the mount and arranged to supply air to the extremities of the space; or (3) An attachment for temporary ductwork at the mount with enough ductway in the ventilated space and temporary ductwork stowed aboard the vessel to supply air...

  15. Modelled Circulation In Storfjorden

    Science.gov (United States)

    Skogseth, R.; Asplin, L.

    The model area Storfjorden is situated between the islands Spitsbergen, Barentsöya and Edgeöya at the Svalbard Archipelago. The entrance of Storfjorden is defined by a shallow bank Storfjordbanken and some small islands Tusenöyane in southeast, and by an 115m deep sill at about 76 45' N in the south. Maximum depth in Storfjorden is 190m, which is surrounded by gradually shallower shelves in the north, the east and southeast. A steep bottom slope is present on the western side of Storfjorden. He- leysundet and Freemansundet, two sounds between respectively Spitsbergen and Bar- entsöya, and Barentsöya and Edgeöya, define two narrow and shallow entrances in the north and northeast connecting Storfjorden with the northwestern Barents Sea. Strong tidal currents exist in Heleysundet (4-5ms-1) and Freemansundet (2-3ms-1), but the general circulation in Storfjorden is not well known. The coastal current in Storfjor- den is cyclonic directed into Storfjorden south of Edgeöya from the East Spitsbergen Current and out of Storfjorden south of Spitsbergen where it is called Sørkappstrøm- men. A three-dimensional sigma layered numerical ocean model called Bergen Ocean Model (BOM) was used to simulate the circulation in Storfjorden with Freemansundet opened. Two simulations were carried out, one with heat flux (100 Wm-2) and one without heat flux from the ocean to the atmosphere. The heat flux was applied only in the proper fjord area north of the sill and not outside as a crude approximation of the effects of a polynya in the sea ice cover during winter. Both simulations had a 4km horizontal resolution and 21 sigma layers. The model is forced by winds (from the NCEP reanalyzed fields) and tides. Initial fields are from the DNMI/IMR climatol- ogy. The model simulation without heat flux gave a circulation heavily dependent on tidal forcing, showing strong tidal currents up to 2ms-1 in Freemansundet, between Tusenöyane and on Storfjordbanken southwest of Edgeöya. Earlier

  16. Cereral Circulation in Preeclampsia

    Directory of Open Access Journals (Sweden)

    A. A. Ivshin

    2008-01-01

    Full Text Available Objective: to evaluate the possibilities of using transcranial Doppler study in pregnant women and pueperas with preeclamp-sia. Subjects and methods. Two hundred and thirty-two pregnant women diagnosed as having varying preeclampsia were prospectively studied. A comparison group comprised 90 apparently healthy women in the third trimester of pregnancy. All the respondents underwent transcranial duplex scanning of the medial cerebral artery with the linear velocity values being determined. A number of the values reflecting the level of perfusion and intracranial pressures, hydrodynamic resistance in the system, cerebrovascular responsiveness and the state of the vascular wall were calculated. Correlation analysis was made between the parameters of cerebral circulation and the severity of preeclampsia, proteinuria, the severity of hydrops, and the parameters of central and peripheral hemodynamics. Results. The findings suggest that there is impaired cerebral perfusion in pregnant women and puerperas with varying preeclampsia, the severity of cerebral circulatory disorders being in proportion with that of preeclampsia. There is a close correlation between cerebral circulation and the individual criteria determining the severity of preeclampsia. The linear values of the Doppler spectrum, namely linear flow characteristics, are prognos-tically most significant. Conclusion. The introduction of transcranial Doppler study into obstetric care has permitted the authors not only to study cerebral circulatory disorders in healthy and pregnant women and puerperas with preeclampia in detail, but also to establish a number of highly significant prognostic criteria for the severity of this life-threatening complication of gestation. The results of transcranial Doppler study assist practitioners in timely and accurately solving the problems in the diagnosis of preeclampsia and in evaluating its severity. Cerebral circulatory values may be successfully used to

  17. Resolvability in Circulant Graphs

    Institute of Scientific and Technical Information of China (English)

    Muhammad SALMAN; Imran JAVAID; Muhammad Anwar CHAUDHRY

    2012-01-01

    A set W of the vertices of a connected graph G is called a resolving set for G if for every two distinct vertices u,v ∈ V(G) there is a vertex w ∈ W such that d(u,w) ≠ d(v,w).A resolving set of minimum cardinality is called a metric basis for G and the number of vertices in a metric basis is called the metric dimension of G,denoted by dim(G).For a vertex u of G and a subset S of V(G),the distance between u and S is the number mins∈s d(u,s).A k-partition H ={S1,S2,...,Sk} of V(G) is called a resolving partition if for every two distinct vertices u,v ∈ V(G) there is a set Si in Π such that d(u,Si) ≠ d(v,Si).The minimum k for which there is a resolving k-partition of V(G) is called the partition dimension of G,denoted by pd(G).The circulant graph is a graph with vertex set Zn,an additive group ofintegers modulo n,and two vertices labeled i and j adjacent if and only if i - j (mod n) ∈ C,where C C Zn has the property that C =-C and 0(∈) C.The circulant graph is denoted by Xn,△ where A =|C|.In this paper,we study the metric dimension of a family of circulant graphs Xn,3 with connection set C ={1,-n/2,n - 1} and prove that dim(Xn,3) is independent of choice of n by showing that 3 for all n =0 (mod 4),dim(X,n,3) ={ 4 for all n =2 (mod 4).We also study the partition dimension of a family of circulant graphs Xn,4 with connection set C ={±1,±2} and prove that pd(Xn,4) is independent of choice of n and show that pd(X5,4) =5 and 3 forall odd n≥9,pd(Xn,4) ={ 4 for all even n ≥ 6 and n =7.

  18. Single-particle behaviour in circulating fluidized beds

    DEFF Research Database (Denmark)

    Weinell, Claus Erik; Dam-Johansen, Kim; Johnsson, Jan Erik

    1997-01-01

    This paper describes an experimental investigation of single-particle behaviour in a cold pilot-scale model of a circulating fluidized bed combustor (CFBC). In the system, sand is recirculated by means of air. Pressure measurements along the riser are used to determine the suspension density...

  19. North Atlantic Circulation

    Science.gov (United States)

    Molinari, R.; Bryan, K.; Schott, F.

    The intensity of the North Atlantic winddriven and thermohaline circulation and the close proximity of many oceanographic installations make the North Atlantic a particularly favored region of the world ocean from the standpoint of research in ocean circulation. Recent increases in available data and advances in numerical modeling techniques served as the impetus to convene a joint workshop of modelers and observers working on the North Atlantic with the Scientific Committee on Oceanic Research (SCOR) Working Group (WG) 68 (“North Atlantic Circulation”). Goals of the workshop were to provide an update on data sets and models and to discuss the poleward heat flux problem and possible monitoring strategies. The joint Workshop/SCOR WG-68 meeting was convened by F. Schott (chairman of the working group; Rosenstiel School of Marine and Atmospheric Science, Miami, Fla.), K. Bryan (National Oceanic and Atmospheric Administration/ Geophysical Fluid Dynamics Laboratory (NOAA/GFDL)), and R. Molinari (NOAA/Atlantic Oceanographic and Meteorological Laboratory (NOAA/AOML)).

  20. Circulation of Stars

    Science.gov (United States)

    Boitani, P.

    2016-01-01

    Since the dawn of man, contemplation of the stars has been a primary impulse in human beings, who proliferated their knowledge of the stars all over the world. Aristotle sees this as the product of primeval and perennial “wonder” which gives rise to what we call science, philosophy, and poetry. Astronomy, astrology, and star art (painting, architecture, literature, and music) go hand in hand through millennia in all cultures of the planet (and all use catasterisms to explain certain phenomena). Some of these developments are independent of each other, i.e., they take place in one culture independently of others. Some, on the other hand, are the product of the “circulation of stars.” There are two ways of looking at this. One seeks out forms, the other concentrates on the passing of specific lore from one area to another through time. The former relies on archetypes (for instance, with catasterism), the latter constitutes a historical process. In this paper I present some of the surprising ways in which the circulation of stars has occurred—from East to West, from East to the Far East, and from West to East, at times simultaneously.

  1. Lost circulation technology development status

    Energy Technology Data Exchange (ETDEWEB)

    Glowka, D.A.; Schafer, D.M.; Loeppke, G.E.; Scott, D.D.; Wernig, M.D.; Wright, E.K.

    1992-07-01

    Lost circulation is the loss of drilling fluid from the wellbore to fractures or pores in the rock formation. In geothermal drilling, lost circulation is often a serious problem that contributes greatly to the cost of the average geothermal well. The Lost Circulation Technology Development Program is sponsored at Sandia National Laboratories by the US Department of Energy. The goal of the program is to reduce lost circulation costs by 30--50% through the development of mitigation and characterization technology. This paper describes the technical progress made in this program during the period April 1991--March 1992. 8 refs.

  2. Percutaneous interventions in Fontan circulation

    Directory of Open Access Journals (Sweden)

    Eduardo Franco

    2015-09-01

    Conclusions: Interventional catheterization procedures are often necessary to reach and maintain the fragile Fontan circulation, mainly in patients with right morphology systemic ventricles and fenestrated Fontan conduits.

  3. Laboratory Performance Testing of Residential Window Air Conditioners

    Energy Technology Data Exchange (ETDEWEB)

    Winkler, J.; Booten, C.; Christensen, D.; Tomerlin, J.

    2013-03-01

    Window air conditioners are the dominant cooling product for residences, in terms of annual unit sales. They are inexpensive, portable and can be installed by the owner. For this reason, they are an attractive solution for supplemental cooling, for retrofitting air conditioning into a home which lacks ductwork, and for renters. Window air conditioners for sale in the United States are required to meet very modest minimum efficiency standards. Four window air conditioners' performance were tested in the Advanced HVAC Systems Laboratory on NREL's campus in Golden, CO. In order to separate and study the refrigerant system's performance, the unit's internal leakage pathways, the unit's fanforced ventilation, and the leakage around the unit resulting from installation in a window, a series of tests were devised that focused on each aspect of the unit's performance. These tests were designed to develop a detailed performance map to determine whole-house performance in different climates. Even though the test regimen deviated thoroughly from the industry-standard ratings test, the results permit simple calculation of an estimated rating for both capacity and efficiency that would result from a standard ratings test. Using this calculation method, it was found that the three new air conditioners' measured performance was consistent with their ratings. This method also permits calculation of equivalent SEER for the test articles. Performance datasets were developed across a broad range of indoor and outdoor operating conditions, and used them to generate performance maps.

  4. Modeling the Air Flow in the 3410 Building Filtered Exhaust Stack System

    Energy Technology Data Exchange (ETDEWEB)

    Recknagle, Kurtis P.; Barnett, J. Matthew; Suffield, Sarah R.

    2013-01-23

    Additional ventilation capacity has been designed for the 3410 Building filtered exhaust stack system. The updated system will increase the number of fans from two to three and will include ductwork to incorporate the new fan into the existing stack. Stack operations will involve running various two-fan combinations at any given time. The air monitoring system of the existing two-fan stack was previously found to be in compliance with the ANSI/HPS N13.1-1999 standard, however it is not known if the modified (three-fan) system will comply. Subsequently, a full-scale three-dimensional (3-D) computational fluid dynamics (CFD) model of the modified stack system has been created to examine the sampling location for compliance with the standard. The CFD modeling results show good agreement with testing data collected from the existing 3410 Building stack and suggest that velocity uniformity and flow angles will remain well within acceptance criteria when the third fan and associated ductwork is installed. This includes two-fan flow rates up to 31,840 cfm for any of the two-fan combinations. For simulation cases in which tracer gas and particles are introduced in the main duct, the model predicts that both particle and tracer gas coefficients of variance (COVs) may be larger than the acceptable 20 percent criterion of the ANSI/HPS N13.1-1999 standard for each of the two-fan, 31,840 cfm combinations. Simulations in which the tracers are introduced near the fans result in improved, though marginally acceptable, COV values for the tracers. Due to the remaining uncertainty that the stack will qualify with the addition of the third fan and high flow rates, a stationary air blender from Blender Products, Inc. is considered for inclusion in the stack system. A model of the air blender has been developed and incorporated into the CFD model. Simulation results from the CFD model that includes the air blender show striking improvements in tracer gas mixing and tracer particle

  5. Evaluation of simplified ventilation system with direct air supply through the facade in a school in a cold climate

    Energy Technology Data Exchange (ETDEWEB)

    Mysen, M. [Norwegian Building Research Institute, Blindern, Oslo (Norway); Department of Energy and Process Technology, Norwegian University of Science and Technology (NTNU), Trondheim (Norway); Schild, P. G.; Hellstrand, V.; Thunshelle, K. [Norwegian Building Research Institute, Blindern, Oslo (Norway)

    2004-07-01

    Many educational buildings in industrialised countries have poor indoor climate, according to today's knowledge about the impact of indoor climate on well-being and productivity. Budget restrictions and practical limitations such as lack of space for central air handling units and ventilation ducts, have motivated the application of simplified ventilation systems in some schools, such as taking unconditioned supply air directly from the facade. One such school was recently evaluated in Norway. On cold days, thermal comfort in the classroom deteriorated due to cold down draught from the supply outlet. In addition, moist and fertile conditions for microbiological growth were observed in the air supply ductwork. On the other hand the same pupils are more satisfied with the school and have less sick building syndrome (SBS) symptoms during winter than summer. An improved control strategy with a temperature-compensated CO{sub 2} set-point for controlling the air flow is suggested. This could improve thermal comfort and reduce energy use without compromising perceived air quality (PAQ) during cold weather. Furthermore it could improve indoor air quality (IAQ) during warm weather with only a slight increase of energy use. Further evaluation of an improved solution is needed before such a ventilation concept can be recommended in cold climates. (author)

  6. 21 CFR 890.5160 - Air-fluidized bed.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Air-fluidized bed. 890.5160 Section 890.5160 Food... DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5160 Air-fluidized bed. (a) Identification. An air-fluidized bed is a device employing the circulation of filtered air through...

  7. Sino-Danish Brain Circulation

    DEFF Research Database (Denmark)

    Bertelsen, Rasmus Gjedssø; Du, Xiangyun; Søndergaard, Morten Karnøe

    2014-01-01

    China is faced with urgent needs to develop an economically and environmentally sustainable economy based on innovation and knowledge. Brain circulation and research and business investments from the outside are central for this development. Sino-American brain circulation and research...... and investment by overseas researchers and entrepreneurs are well described. In that case, the US is the center of global R&D and S&T. However, the brain circulation and research and investments between a small open Scandinavian economy, such as Denmark, and the huge developing economy of China are not well...... understood. In this case, Denmark is very highly developed, but a satellite in the global R&D and S&T system. With time and the growth of China as a R&D and S&T power house, both Denmark and China will benefit from brain circulation between them. Such brain circulation is likely to play a key role in flows...

  8. Field measurements of efficiency and duct retrofit effectiveness in residential forced air distributions systems

    Energy Technology Data Exchange (ETDEWEB)

    Jump, D.A.; Walker, I.S.; Modera, M.P.

    1996-08-01

    Forced air distribution systems can have a significant impact on the energy consumed in residences. It is common practice in U.S. residential buildings to place such duct systems outside the conditioned space. This results in the loss of energy by leakage and conduction to the surroundings. In order to estimate the magnitudes of these losses, 24 houses in the Sacramento, California, area were tested before and after duct retrofitting. The systems in these houses included conventional air conditioning, gas furnaces, electric furnaces and heat pumps. The retrofits consisted of sealing and insulating the duct systems. The field testing consisted of the following measurements: leakage of the house envelopes and their ductwork, flow through individual registers, duct air temperatures, ambient temperatures, surface areas of ducts, and HVAC equipment energy consumption. These data were used to calculate distribution system delivery efficiency as well as the overall efficiency of the distribution system including all interactions with building load and HVAC equipment. Analysis of the test results indicate an average increase in delivery efficiency from 64% to 76% and a corresponding average decrease in HVAC energy use of 18%. This paper summarizes the pre- and post-retrofit efficiency measurements to evaluate the retrofit effectiveness, and includes cost estimates for the duct retrofits. The impacts of leak sealing and insulating will be examined separately. 8 refs., 1 fig., 4 tabs.

  9. Practicality study on air-powered vehicle

    Institute of Scientific and Technical Information of China (English)

    Lin LIU; Xiaoli YU

    2008-01-01

    To investigate the feasibility and outlook of air-powered vehicles including compressed air-powered vehicle and liquid nitrogen-powered vehicle, thermodyn-amic analysis and experiment data were used to analyze the energy density, performance, safety, running effi-ciency, fuel circulation economy and consumer accep-tance, etc. The results show that compressed air and liquid nitrogen have similar energy density as Ni-H battery; the characteristics of an air-powered engine is suitable for driving a vehicle; the circulation efficiency of liquid nitrogen is 3.6%-14% and that of compressed air is 25%-32.3% in practice, and existing technology can assure its safety. It is concluded that though the performance of an air-powered engine is inferior to that of the traditional inert combustion engine, an air-powered vehicle is fit for future green cars to realize the sustainable development of society and environment.

  10. The circulation physiology of agroecosystems

    Institute of Scientific and Technical Information of China (English)

    Cao Zhiping; Richard Dawson

    2007-01-01

    This paper represents an effort to enlarge the understanding of the biophysical foundation of agroecosystems by using an analogy with the circulation of the blood in the human body. The circulation function in the human body can be represented as arterial pressure. The factors affecting arterial pressure in the human body have direct counterparts in the cultivation-husbandry system. The relationship between circulation pressure and the factors affecting that pressure in the cultivation-husbandry system are similar to the relationship between the arterial pressure and factors affecting arterial pressure in the human body. Furthermore, circulation resistance in the cultivation-husbandry system can be shown to be analogous to the calculation of peripheral resistance in the human body by Poiseuille's formula.

  11. Air Pollution

    Science.gov (United States)

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, dust, ... a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  12. Results of theoretical and experimental studies of hydrodynamics of circulation loops in circulating fluidized bed reactors and systems with interconnected reactors

    Science.gov (United States)

    Ryabov, G. A.; Folomeev, O. M.; Sankin, D. A.; Melnikov, D. A.

    2015-02-01

    Problems of the calculation of circulation loops in circulating fluidized bed reactors and systems with interconnected reactors (polygeneration systems for the production of electricity, heat, and useful products and chemical cycles of combustion and gasification of solid fuels)are considered. A method has been developed for the calculation of circulation loop of fuel particles with respect to boilers with circulating fluidized bed (CFB) and systems with interconnected reactors with fluidized bed (FB) and CFB. New dependences for the connection between the fluidizing agent flow (air, gas, and steam) and performance of reactors and for the whole system (solids flow rate, furnace and cyclone pressure drops, and bed level in the riser) are important elements of this method. Experimental studies of hydrodynamics of circulation loops on the aerodynamic unit have been conducted. Experimental values of pressure drop of the horizontal part of the L-valve, which satisfy the calculated dependence, have been obtained.

  13. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    Keith, Raymond E.; Heller, Thomas J.; Bush, Stuart A.

    1991-01-01

    This Annual Report on Colorado-Ute Electric Association's NUCLA Circulating Fluidized Bed (CFB) Demonstration Program covers the period from February 1987 through December 1988. The outline for presentation in this report includes a summary of unit operations along with individual sections covering progress in study plan areas that commenced during this reporting period. These include cold-mode shakedown and calibration, plant commercial performance statistics, unit start-up (cold), coal and limestone preparation and handling, ash handling system performance and operating experience, tubular air heater, baghouse operation and performance, materials monitoring, and reliability monitoring. During this reporting period, the coal-mode shakedown and calibration plan was completed. (VC)

  14. The South Asian Monsoon Circulation in Moist Isentropic coordinates

    Science.gov (United States)

    Thazhe Purayil, Sabin; Pauluis, Olivier

    2016-04-01

    The atmospheric circulation and thermodynamic structure during the South Asian Summer Monsoon season is analyzed in isentropic coordinates through the mass transport represented in terms of the potential temperature and equivalent potential temperature. This approach, originally developed to analyze the global meridional circulation, makes it possible to identify the thermodynamic properties of the inflow and outflow of different air mass. To understand the thermodynamic properties of air mass in south Asian monsoon region, we have used three diagnostics; a) the joint distribution of the mass transport as a function of dry and moist entropy, b) the vertical mass flux over the monsoon domain and c) the mass transport and isentropic thickness for different moist ventilation range of tropical atmosphere. The thermodynamic properties of the various air masses, such as the inflow of warm moist air in the boundary layer, upper tropospheric outflow, and midlatitude dry air intrusion are being systematically identified. The isentropic distribution of the vertical mass flux transport in terms of equivalent potential temperature is used to explain the characteristics of ascending and descending air parcels over the Indian subcontinent. Diagnosis based on the isentropic thickness reveals that the regional monsoon circulation and associated precipitation features can be systematically explained by this method. This technique is used to study the evolution of the monsoon flow in the seasonal scale. We used the data from AMIP-type simulations carried out with prescribed Sea Surface Temperature and sea ice for a 25 year period (1981-2005) from the GFDL High-resolution atmospheric model (HiRAM) with an average grid spacing of ~25km over the globe.

  15. Drivers of uncertainty in simulated ocean circulation and heat uptake

    Science.gov (United States)

    Huber, Markus B.; Zanna, Laure

    2017-02-01

    The impact of uncertainties in air-sea fluxes and ocean model parameters on the ocean circulation and ocean heat uptake (OHU) is assessed in a novel modeling framework. We use an ocean-only model forced with the simulated sea surface fields of the CMIP5 climate models. The simulations are performed using control and 1% CO2 warming scenarios. The ocean-only ensemble adequately reproduces the mean Atlantic Meridional Overturning Circulation (AMOC) and the zonally integrated OHU. The ensemble spread in AMOC strength, its weakening, and Atlantic OHU due to different air-sea fluxes is twice as large as the uncertainty range related to vertical and mesocale eddy diffusivities. The sensitivity of OHU to uncertainties in air-sea fluxes and model parameters differs vastly across basins, with the Southern Ocean exhibiting strong sensitivity to air-sea fluxes and model parameters. This study clearly demonstrates that model biases in air-sea fluxes are one of the key sources of uncertainty in climate simulations.

  16. Seasonal overturning circulation in the Red Sea: 2. Winter circulation

    KAUST Repository

    Yao, Fengchao

    2014-04-01

    The shallow winter overturning circulation in the Red Sea is studied using a 50 year high-resolution MITgcm (MIT general circulation model) simulation with realistic atmospheric forcing. The overturning circulation for a typical year, represented by 1980, and the climatological mean are analyzed using model output to delineate the three-dimensional structure and to investigate the underlying dynamical mechanisms. The horizontal model circulation in the winter of 1980 is dominated by energetic eddies. The climatological model mean results suggest that the surface inflow intensifies in a western boundary current in the southern Red Sea that switches to an eastern boundary current north of 24N. The overturning is accomplished through a cyclonic recirculation and a cross-basin overturning circulation in the northern Red Sea, with major sinking occurring along a narrow band of width about 20 km along the eastern boundary and weaker upwelling along the western boundary. The northward pressure gradient force, strong vertical mixing, and horizontal mixing near the boundary are the essential dynamical components in the model\\'s winter overturning circulation. The simulated water exchange is not hydraulically controlled in the Strait of Bab el Mandeb; instead, the exchange is limited by bottom and lateral boundary friction and, to a lesser extent, by interfacial friction due to the vertical viscosity at the interface between the inflow and the outflow. Key Points Sinking occurs in a narrow boundary layer along the eastern boundary Surface western boundary current switches into an eastern boundary current Water exchange in the Strait of Bab el Mandeb is not hydraulically controlled © 2014. American Geophysical Union. All Rights Reserved.

  17. The Invertibility, Explicit Determinants, and Inverses of Circulant and Left Circulant and g-Circulant Matrices Involving Any Continuous Fibonacci and Lucas Numbers

    Directory of Open Access Journals (Sweden)

    Zhaolin Jiang

    2014-01-01

    Full Text Available Circulant matrices play an important role in solving delay differential equations. In this paper, circulant type matrices including the circulant and left circulant and g-circulant matrices with any continuous Fibonacci and Lucas numbers are considered. Firstly, the invertibility of the circulant matrix is discussed and the explicit determinant and the inverse matrices by constructing the transformation matrices are presented. Furthermore, the invertibility of the left circulant and g-circulant matrices is also studied. We obtain the explicit determinants and the inverse matrices of the left circulant and g-circulant matrices by utilizing the relationship between left circulant, g-circulant matrices and circulant matrix, respectively.

  18. Atmospheric circulation classification comparison based on wildfires in Portugal

    Science.gov (United States)

    Pereira, M. G.; Trigo, R. M.

    2009-04-01

    Atmospheric circulation classifications are not a simple description of atmospheric states but a tool to understand and interpret the atmospheric processes and to model the relation between atmospheric circulation and surface climate and other related variables (Radan Huth et al., 2008). Classifications were initially developed with weather forecasting purposes, however with the progress in computer processing capability, new and more robust objective methods were developed and applied to large datasets prompting atmospheric circulation classification methods to one of the most important fields in synoptic and statistical climatology. Classification studies have been extensively used in climate change studies (e.g. reconstructed past climates, recent observed changes and future climates), in bioclimatological research (e.g. relating human mortality to climatic factors) and in a wide variety of synoptic climatological applications (e.g. comparison between datasets, air pollution, snow avalanches, wine quality, fish captures and forest fires). Likewise, atmospheric circulation classifications are important for the study of the role of weather in wildfire occurrence in Portugal because the daily synoptic variability is the most important driver of local weather conditions (Pereira et al., 2005). In particular, the objective classification scheme developed by Trigo and DaCamara (2000) to classify the atmospheric circulation affecting Portugal have proved to be quite useful in discriminating the occurrence and development of wildfires as well as the distribution over Portugal of surface climatic variables with impact in wildfire activity such as maximum and minimum temperature and precipitation. This work aims to present: (i) an overview the existing circulation classification for the Iberian Peninsula, and (ii) the results of a comparison study between these atmospheric circulation classifications based on its relation with wildfires and relevant meteorological

  19. Circulating Fibronectin Controls Tumor Growth

    Directory of Open Access Journals (Sweden)

    Anja von Au

    2013-08-01

    Full Text Available Fibronectin is ubiquitously expressed in the extracellular matrix, and experimental evidence has shown that it modulates blood vessel formation. The relative contribution of local and circulating fibronectin to blood vessel formation in vivo remains unknown despite evidence for unexpected roles of circulating fibronectin in various diseases. Using transgenic mouse models, we established that circulating fibronectin facilitates the growth of bone metastases by enhancing blood vessel formation and maturation. This effect is more relevant than that of fibronectin produced by endothelial cells and pericytes, which only exert a small additive effect on vessel maturation. Circulating fibronectin enhances its local production in tumors through a positive feedback loop and increases the amount of vascular endothelial growth factor (VEGF retained in the matrix. Both fibronectin and VEGF then cooperate to stimulate blood vessel formation. Fibronectin content in the tumor correlates with the number of blood vessels and tumor growth in the mouse models. Consistent with these results, examination of three separate arrays from patients with breast and prostate cancers revealed that a high staining intensity for fibronectin in tumors is associated with increased mortality. These results establish that circulating fibronectin modulates blood vessel formation and tumor growth by modifying the amount of and the response to VEGF. Furthermore, determination of the fibronectin content can serve as a prognostic biomarker for breast and prostate cancers and possibly other cancers.

  20. 24 CFR 3280.715 - Circulating air systems.

    Science.gov (United States)

    2010-04-01

    ... effective thermal resistance (R) of not less than 4.0 unless they are within manufactured home insulation having a minimum effective value of R-4.0 for floors or R-6.0 for ceilings. (7) Supply and return ducts... minimum thermal resistance of R=4.0, with a continuous vapor barrier having a perm rating of not more...

  1. Atmospheric Circulation of Terrestrial Exoplanets

    CERN Document Server

    Showman, Adam P; Merlis, Timothy M; Kaspi, Yohai

    2013-01-01

    The investigation of planets around other stars began with the study of gas giants, but is now extending to the discovery and characterization of super-Earths and terrestrial planets. Motivated by this observational tide, we survey the basic dynamical principles governing the atmospheric circulation of terrestrial exoplanets, and discuss the interaction of their circulation with the hydrological cycle and global-scale climate feedbacks. Terrestrial exoplanets occupy a wide range of physical and dynamical conditions, only a small fraction of which have yet been explored in detail. Our approach is to lay out the fundamental dynamical principles governing the atmospheric circulation on terrestrial planets--broadly defined--and show how they can provide a foundation for understanding the atmospheric behavior of these worlds. We first survey basic atmospheric dynamics, including the role of geostrophy, baroclinic instabilities, and jets in the strongly rotating regime (the "extratropics") and the role of the Hadle...

  2. Circulation in blast driven instabilities

    Science.gov (United States)

    Henry de Frahan, Marc; Johnsen, Eric

    2016-11-01

    Mixing in many natural phenomena (e.g. supernova collapse) and engineering applications (e.g. inertial confinement fusion) is often initiated through hydrodynamic instabilities. Explosions in these systems give rise to blast waves which can interact with perturbations at interfaces between different fluids. Blast waves are formed by a shock followed by a rarefaction. This wave profile leads to complex time histories of interface acceleration. In addition to the instabilities induced by the acceleration field, the rarefaction from the blast wave decompresses the material at the interface, further increasing the perturbation growth. After the passage of the wave, circulation circulation generated by the blast wave through baroclinic vorticity continues to act upon the interface. In this talk, we provide scaling laws for the circulation and amplitude growth induced by the blast wave. Numerical simulations of the multifluid Euler equations solved using a high-order accurate Discontinuous Galerkin method are used to validate the theoretical results.

  3. Combination sound and vibration isolation curb for rooftop air-handling systems

    Science.gov (United States)

    Paige, Thomas S.

    2005-09-01

    This paper introduces the new Model ESSR Sound and Vibration Isolation Curb manufactured by Kinetics Noise Control, Inc. This product was specially designed to address all of the common transmission paths associated with noise and vibration sources from roof-mounted air-handling equipment. These include: reduction of airborne fan noise in supply and return air ductwork, reduction of duct rumble and breakout noise, reduction of direct airborne sound transmission through the roof deck, and reduction of vibration and structure-borne noise transmission to the building structure. Upgrade options are available for increased seismic restraint and wind-load protection. The advantages of this new system over the conventional approach of installing separate duct silencers in the room ceiling space below the rooftop unit are discussed. Several case studies are presented with the emphasis on completed projects pertaining to classrooms and school auditorium applications. Some success has also been achieved by adding active noise control components to improve low-frequency attenuation. This is an innovative product designed for conformance with the new classroom acoustics standard ANSI S12.60.

  4. A pneumatic pressure-driven multi-throughput microfluidic circulation culture system.

    Science.gov (United States)

    Satoh, T; Narazaki, G; Sugita, R; Kobayashi, H; Sugiura, S; Kanamori, T

    2016-06-21

    Here, we report a pneumatic pressure-driven microfluidic device capable of multi-throughput medium circulation culture. The circulation culture system has the following advantages for application in drug discovery: (i) simultaneous operation of multiple circulation units, (ii) use of a small amount of circulating medium (3.5 mL), (iii) pipette-friendly liquid handling, and (iv) a detachable interface with pneumatic pressure lines via sterile air-vent filters. The microfluidic device contains three independent circulation culture units, in which human umbilical vein endothelial cells (HUVECs) were cultured under physiological shear stress induced by circulation of the medium. Circulation of the medium in the three culture units was generated by programmed sequentially applied pressure from two pressure-control lines. HUVECs cultured in the microfluidic device were aligned under a one-way circulating flow with a shear stress of 10 dyn cm(-2); they exhibited a randomly ordered alignment under no shear stress and under reciprocating flow with a shear stress of 10 dyn cm(-2). We also observed 2.8- to 4.9-fold increases in expression of the mRNAs of endothelial nitric oxide synthase and thrombomodulin under one-way circulating flow with a shear stress of 10 dyn cm(-2) compared with conditions of no shear stress or reciprocating flow.

  5. Ultraviolet germicidal irradiation inactivation of airborne fungal spores and bacteria in upper-room air and HVAC in-duct configurations

    Energy Technology Data Exchange (ETDEWEB)

    Kujundzic, E.; Hernandez, M. [Colorado Univ., Boulder, CO (United States). Dept. of Civil, Environmental and Architectural Engineering; Miller, S.L. [Colorado Univ., Boulder, CO (United States). Dept. of Mechanical Engineering

    2007-01-15

    This article presented an evaluation of the efficiency of ultraviolet germicidal irradiation (UVGI) for inactivating airborne fungal spores and bacterial vegetative cells under 3 configurations, namely intrinsic, upper-room air, and in-duct. Several experiments were conducted in a pilot-scale chamber fitted with 4 corner ultraviolet lamps that irradiated the entire chamber; a full-scale room fitted with a UVGI system that irradiated the top 30 cm of the room; and, the supply air duct of a heating ventilation and air-conditioning (HVAC) system. Fungal spores and vegetative cells of bacterium were aerosolized regularly such that their numbers and physiologic state were comparable both with and without the UVGI lamps operating. The article provided information on the materials and methods used including the experimental facilities (pilot-scale chamber, full-scale room, and in-duct UVGI system and ductwork) as well as the methods used for the three experimental studies. It also discussed the bioaerosol generation and sampling and quantification. These included culturing and direct microscopy. UV fluence rate was described. Last, the the results, discussion and conclusions from the studies were presented. It was shown that increasing the air stream velocity through the supply air duct reduces the residence time of bioaerosol being exposed to in-duct UVGI. 36 refs., 3 figs.

  6. A seasonal model of the Mediterranean Sea general circulation

    Science.gov (United States)

    Roussenov, Vassil; Stanev, Emil; Artale, Vincenzo; Pinardi, Nadia

    1995-07-01

    This paper describes the seasonal characteristics of the Mediterranean Sea general circulation as simulated by a primitive equation general circulation model. The forcing is composed of climatological monthly mean atmospheric parameters, which are used to compute the heat and momentum budgets at the air-sea interface of the model. This allows heat fluxes to be determined by a realistic air-sea interaction physics. The Strait of Gibraltar is open, and the model resolution is ? in the horizontal and 19 levels in the vertical. The results show the large seasonal cycle of the circulation and its transient characteristics. The heat budget at the surface is characterized by lateral boundary intensifications occurring in downwelling and up welling areas of the basin. The general circulation is composed of subbasin gyres, and cyclonic motion dominates the northern and anticyclonic motion the southern part of the basin. The Atlantic stream which enters from Gibraltar and assumes the form of different boundary current subsystems is a coherent structure at the surface. At depth it appears as current segments and jets around a vigorous gyre system. The seasonal variability is manifested not only by a change in amplitude and location of the gyres but also by the appearance of seasonally recurrent gyres in different parts of the basin. Distinct westward propagation of these gyres occurs, together with amplitude changes. For the first time a Mersa-Matruh Gyre is successfully simulated due to the introduction of our heat fluxes at the air-sea interface. The seasonal thermocline is formed each summer, and a deep winter mixed layer is produced in the region of Levantine intermediate water formation. Deep water renewal does not occur, probably due to the climatological forcing used.

  7. VanderLaan Circulant Type Matrices

    Directory of Open Access Journals (Sweden)

    Hongyan Pan

    2015-01-01

    Full Text Available Circulant matrices have become a satisfactory tools in control methods for modern complex systems. In the paper, VanderLaan circulant type matrices are presented, which include VanderLaan circulant, left circulant, and g-circulant matrices. The nonsingularity of these special matrices is discussed by the surprising properties of VanderLaan numbers. The exact determinants of VanderLaan circulant type matrices are given by structuring transformation matrices, determinants of well-known tridiagonal matrices, and tridiagonal-like matrices. The explicit inverse matrices of these special matrices are obtained by structuring transformation matrices, inverses of known tridiagonal matrices, and quasi-tridiagonal matrices. Three kinds of norms and lower bound for the spread of VanderLaan circulant and left circulant matrix are given separately. And we gain the spectral norm of VanderLaan g-circulant matrix.

  8. Conservation of Circulation in Magnetohydrodynamics

    CERN Document Server

    Bekenstein, J D; Bekenstein, Jacob D.; Oron, Asaf

    2000-01-01

    We demonstrate, both at the Newtonian and (general) relativistic levels, theexistence of a generalization of Kelvin's circulation theorem (for pure fluids)which is applicable to perfect magnetohydrodynamics. The argument is based onthe least action principle for magnetohydrodynamic flow. Examples of the newconservation law are furnished. The new theorem should be helpful inidentifying new kinds of vortex phenomena distinct from magnetic ropes or fluidvortices.

  9. A Mathematical Model for Differential—Velocity Circulating Fluidized Bed Boiler

    Institute of Scientific and Technical Information of China (English)

    LiZhao; XiangdongXu

    1999-01-01

    The scheme of differential-velocity circulating fluidized bed was put forward by Thermal Engineering Department of Tsinghua university in 1992 and got patent simultaneously.An internal bed material circulation in combustor can be established by the discrepancy of entrainment at different air velocity,and separates the combustor into three different velocity regions,which constitutes the differential-velocity inside circulation.Mathematical modeling and simulation may facilitate understanding,Development and operation of this new process.Here cell model method was adopted to set up the model.

  10. Optimal Backward Perturbation Analysis for the Block Skew Circulant Linear Systems with Skew Circulant Blocks

    Directory of Open Access Journals (Sweden)

    Zhaolin Jiang

    2014-01-01

    Full Text Available We first give the block style spectral decomposition of arbitrary block skew circulant matrix with skew circulant blocks. Secondly, we obtain the singular value of block skew circulant matrix with skew circulant blocks as well. Finally, based on the block style spectral decomposition, we deal with the optimal backward perturbation analysis for the block skew circulant linear system with skew circulant blocks.

  11. Summertime winds and direct cyclonic circulation: observations from Lake Geneva

    Directory of Open Access Journals (Sweden)

    U. Lemmin

    Full Text Available Records of wind, air temperature and air pressure from nine stations, situated along the shoreline of Lake Geneva, Switzerland, were analyzed for the summer period May to September. At all stations the consistent appearance of significant spectral peaks and changes in wind direction at the diurnal frequency indicates the importance of lake-land breezes. It is shown that the surrounding topography has a strong modifying effect (temporal and spatial on the lake-land breeze. Superimposed on this cyclic wind pattern, short episodes of strong winds with long fetch over parts of Lake Geneva are regularly observed. Both of these winds exert a spatially variable wind stress over the lake surface on the same time scale. Typical examples of the expected lake's response are presented, among them the seasonally persistent gyre in the central part of the lake. Evidence is provided that this dominant circulation is part of a direct cyclonic circulation, generated by the curl of the diurnal wind field. It is concluded that the mean circulation is caused by these winds and affected by the topography of the surrounding land.

  12. Heating, ventilating, and air conditioning deactivation thermal analysis of PUREX Plant

    Energy Technology Data Exchange (ETDEWEB)

    Chen, W.W.; Gregonis, R.A. [Westinghouse Hanford Company, Richland, WA (United States)

    1997-08-01

    Thermal analysis was performed for the proposed Plutonium Uranium Extraction Plant exhaust system after deactivation. The purpose of the analysis was to determine if enough condensation will occur to plug or damage the filtration components. A heat transfer and fluid flow analysis was performed to evaluate the thermal characteristics of the underground duct system, the deep-bed glass fiber filter No. 2, and the high-efficiency particulate air filters in the fourth filter building. The analysis is based on extreme variations of air temperature, relative humidity, and dew point temperature using 15 years of Hanford Site weather data as a basis. The results will be used to evaluate the need for the electric heaters proposed for the canyon exhaust to prevent condensation. Results of the analysis indicate that a condition may exist in the underground ductwork where the duct temperature can lead or lag changes in the ambient air temperature. This condition may contribute to condensation on the inside surfaces of the underground exhaust duct. A worst case conservative analysis was performed assuming that all of the water is removed from the moist air over the inside surface of the concrete duct area in the fully developed turbulent boundary layer while the moist air in the free stream will not condense. The total moisture accumulated in 24 hours is negligible. Water puddling would not be expected. The results of the analyses agree with plant operating experiences. The filters were designed to resist high humidity and direct wetting, filter plugging caused by slight condensation in the upstream duct is not a concern. 19 refs., 2 figs.

  13. Effectiveness of HVAC duct cleaning procedures in improving indoor air quality.

    Science.gov (United States)

    Ahmad, I; Tansel, B; Mitrani, J D

    2001-12-01

    Indoor air quality has become one of the most serious environmental concerns as an average person spends about 22 hr indoors on a daily basis. The study reported in this article, was conducted to determine the effectiveness of three commercial HVAC (Heating Ventilation Air Conditioning) duct cleaning processes in reducing the level of airborne particulate matter and viable bioaerosols. The three HVAC sanitation processes were: (1) Contact method (use of conventional vacuum cleaning of interior duct surfaces); (2) Air sweep method (use of compressed air to dislodging dirt and debris); (3) Rotary brush method (insertion of a rotary brush into the ductwork to agitate and dislodge the debris). Effectiveness of these sanitation processes was evaluated in terms of airborne particulate and viable bioaerosol concentrations in residential homes. Eight identical homes were selected in the same neighborhood. Two homes were cleaned using each procedure and two were used as controls. It was found that both particle count readings and bioaerosol concentrations were higher when cleaning was being performed than before or after cleaning, which suggests that dirt, debris and other pollutants may become airborne as a result of disturbances caused by the cleaning processes. Particle count readings at 0.3 micron size were found to have increased due to cigarette smoking. Particle counts at 1.0 micron size were reduced due to HVAC duct cleaning. Post-level bioaerosol concentrations, taken two days after cleaning, were found to be lower than the pre-level concentrations suggesting that the cleaning procedures were effective to some extent. Homes cleaned with the Air Sweep procedure showed the highest degree of reduction in bioaerosol concentration among the three procedures investigated.

  14. Protective supplied-breathing-air garment

    Science.gov (United States)

    Childers, E.L.; von Hortenau, E.F.

    1982-05-28

    A breathing-air garment for isolating a wearer from hostile environments containing toxins or irritants is disclosed. The garment includes a suit and a separate head-protective enclosure or hood engaging a suit collar in sealing attachment. The hood and suit collar are cylindrically shaped and dimensioned to enable the wearer to withdraw his hands from the suit sleeves to perform manual tasks within the hood interior. Breathing air is supplied from an external air line with an air-delivery hose attached to the hood interior. The hose feeds air into an annular halo-like fiber-filled plenum having spaced discharge orifices attached to the hood top wall. A plurality of air exhaust/check valves located at the suit extremities cooperate with the hood air-delivery system to provide a cooling flow of circulating air from the hood throughout the suit interior. A suit entry seal provided on the suit sealed with an adhesive sealing flap.

  15. Physiology of the fetal circulation.

    Science.gov (United States)

    Kiserud, Torvid

    2005-12-01

    Our understanding of fetal circulatory physiology is based on experimental animal data, and this continues to be an important source of new insight into developmental mechanisms. A growing number of human studies have investigated the human physiology, with results that are similar but not identical to those from animal studies. It is time to appreciate these differences and base more of our clinical approach on human physiology. Accordingly, the present review focuses on distributional patterns and adaptational mechanisms that were mainly discovered by human studies. These include cardiac output, pulmonary and placental circulation, fetal brain and liver, venous return to the heart, and the fetal shunts (ductus venosus, foramen ovale and ductus arteriosus). Placental compromise induces a set of adaptational and compensational mechanisms reflecting the plasticity of the developing circulation, with both short- and long-term implications. Some of these aspects have become part of the clinical physiology of today with consequences for surveillance and treatment.

  16. Proper Sizing of Circulation Pumps

    DEFF Research Database (Denmark)

    Tommerup, Henrik M.; Nørgaard, Jørgen

    2007-01-01

    , but the results can be applied to Europe in general. Despite the small sample of houses involved in the test, 15 houses, some rather safe conclusions can be drawn from the results, which showed that newly developed pumps with power consumption around 5-8 W, can perform the task of circulating the water......The paper describes the preliminary results from field tests of replacing various types of old pumps used for circulating water in heating systems in single- and double-family houses with new types of pumps. The tests were carried out in Denmark for the Danish Electricity Savings Trust...... sufficiently to keep the houses satisfactorily warm during the heating season of the test. The old replaced pumps used 5-10 times more power. In Europe alone, a gradual replacement of the present vastly oversized pumps with such small but sufficient pumps can save the construction of 17 large power plants...

  17. Journalism as Cultures of Circulation

    DEFF Research Database (Denmark)

    Bødker, Henrik

    2013-01-01

    The universe of journalism has always consisted of interspersed texts, meanings and practices. Yet, much journalism research has often isolated either texts and/or contexts and as such assumed relations between professional practices, informed (rational) readers and (conceived) core texts...... of journalism. It is, however, more important than ever to shift attention away from texts to the processes through which they are circulated. This is partly because the many cultural forms of journalism (textual, institutional, technological, material, behavioural and imagined) are undergoing significant......, likes, comments, searches, journalist roles, writing and reading positions and identities etc. Such forms will be traced within the mediation of a specific event with the overall aim of beginning a theorization of the landscape of journalism as highly interrelated cultures of circulation....

  18. Ocean circulation generated magnetic signals

    DEFF Research Database (Denmark)

    Manoj, C.; Kuvshinov, A.; Maus, S.

    2006-01-01

    Conducting ocean water, as it flows through the Earth's magnetic field, generates secondary electric and magnetic fields. An assessment of the ocean-generated magnetic fields and their detectability may be of importance for geomagnetism and oceanography. Motivated by the clear identification...... of ocean tidal signatures in the CHAMP magnetic field data we estimate the ocean magnetic signals of steady flow using a global 3-D EM numerical solution. The required velocity data are from the ECCO ocean circulation experiment and alternatively from the OCCAM model for higher resolution. We assume...... of the magnetic field, as compared to the ECCO simulation. Besides the expected signatures of the global circulation patterns, we find significant seasonal variability of ocean magnetic signals in the Indian and Western Pacific Oceans. Compared to seasonal variation, interannual variations produce weaker signals....

  19. Study on biomass circulation and gasification performance in a clapboard-type internal circulating fluidized bed gasifier.

    Science.gov (United States)

    Zhou, Zhao-qiu; Ma, Long-long; Yin, Xiu-li; Wu, Chuang-zhi; Huang, Li-cheng; Wang, Chu

    2009-01-01

    We investigated the solid particle flow characteristics and biomass gasification in a clapboard-type internal circulating fluidized bed reactor. The effect of fluidization velocity on particle circulation rate and pressure distribution in the bed showed that fluidization velocities in the high and low velocity zones were the main operational parameters controlling particle circulation. The maximum internal circulation rates in the low velocity zone came almost within the range of velocities in the high velocity zone, when u(H)/u(mf)=2.2-2.4 for rice husk and u(H)/u(mf)=3.5-4.5 for quartz sand. In the gasification experiment, the air equivalence ratio (ER) was the main controlling parameter. Rice husk gasification gas had a maximum heating value of around 5000 kJ/m(3) when ER=0.22-0.26, and sawdust gasification gas reached around 6000-6500 kJ/m(3) when ER=0.175-0.24. The gasification efficiency of rice husk reached a maximum of 77% at ER=0.28, while the gasification efficiency of sawdust reached a maximum of 81% at ER=0.25.

  20. Conservation of circulation in magnetohydrodynamics

    Science.gov (United States)

    Bekenstein; Oron

    2000-10-01

    We demonstrate at both the Newtonian and (general) relativistic levels the existence of a generalization of Kelvin's circulation theorem (for pure fluids) that is applicable to perfect magnetohydrodynamics. The argument is based on the least action principle for magnetohydrodynamic flow. Examples of the new conservation law are furnished. The new theorem should be helpful in identifying new kinds of vortex phenomena distinct from magnetic ropes or fluid vortices.

  1. Conservation of Circulation in Magnetohydrodynamics

    OpenAIRE

    Bekenstein, Jacob D.; Oron, Asaf

    2000-01-01

    We demonstrate, both at the Newtonian and (general) relativistic levels, the existence of a generalization of Kelvin's circulation theorem (for pure fluids) which is applicable to perfect magnetohydrodynamics. The argument is based on the least action principle for magnetohydrodynamic flow. Examples of the new conservation law are furnished. The new theorem should be helpful in identifying new kinds of vortex phenomena distinct from magnetic ropes or fluid vortices.

  2. Hall Effect Gyrators and Circulators

    Science.gov (United States)

    Viola, Giovanni; DiVincenzo, David P.

    2014-04-01

    The electronic circulator and its close relative the gyrator are invaluable tools for noise management and signal routing in the current generation of low-temperature microwave systems for the implementation of new quantum technologies. The current implementation of these devices using the Faraday effect is satisfactory but requires a bulky structure whose physical dimension is close to the microwave wavelength employed. The Hall effect is an alternative nonreciprocal effect that can also be used to produce desired device functionality. We review earlier efforts to use an Ohmically contacted four-terminal Hall bar, explaining why this approach leads to unacceptably high device loss. We find that capacitive coupling to such a Hall conductor has much greater promise for achieving good circulator and gyrator functionality. We formulate a classical Ohm-Hall analysis for calculating the properties of such a device, and show how this classical theory simplifies remarkably in the limiting case of the Hall angle approaching 90°. In this limit, we find that either a four-terminal or a three-terminal capacitive device can give excellent circulator behavior, with device dimensions far smaller than the ac wavelength. An experiment is proposed to achieve GHz-band gyration in millimeter (and smaller) scale structures employing either semiconductor heterostructure or graphene Hall conductors. An inductively coupled scheme for realizing a Hall gyrator is also analyzed.

  3. Culturable bacteria in Himalayan ice in response to atmospheric circulation

    Directory of Open Access Journals (Sweden)

    S. Zhang

    2006-06-01

    Full Text Available Only recently has specific attention been given to culturable bacteria in Tibetan glaciers, but their relation to atmospheric circulation is less understood yet. Here we investigate the seasonal variation of culturable bacteria preserved in a Himalayan ice core. High concentration of culturable bacteria in glacial ice deposited during the pre-monsoon season is attributed to the transportation of continental dust stirred up by the frequent dust storms in Northwest China during spring. This is also confirmed by the spatial distribution of culturable bacteria in Tibetan glaciers. Culturable bacteria deposited during monsoon season are more diverse than other seasons because they derive from both marine air masses and local or regional continental sources. We suggest that microorganisms in Himalayan ice can be used to reconstruct atmospheric circulation.

  4. Circulating follistatin in relation to energy metabolism

    DEFF Research Database (Denmark)

    Hansen, Jakob Schiøler; Plomgaard, Peter

    2016-01-01

    Recently, substantial evidence has emerged that the liver contributes significantly to the circulating levels of follistatin and that circulating follistatin is tightly regulated by the glucagon-to-insulin ratio. Both observations are based on investigations of healthy subjects. These novel...... a relation to energy metabolism. In this narrative review, we attempt to reconcile the existing findings on circulating follistatin with the novel concept that circulating follistatin is a liver-derived molecule regulated by the glucagon-to-insulin ratio. The picture emerging is that conditions associated...... with elevated levels of circulating follistatin have a metabolic denominator with decreased insulin sensitivity and/or hyperglucagoneimia....

  5. Impact of Stratospheric Ozone Distribution on Features of Tropospheric Circulation

    Science.gov (United States)

    Barodka, Siarhei; Krasouski, Aliaksandr; Mitskevich, Yaroslav; Shalamyansky, Arkady

    2016-04-01

    In this work we study connections between stratospheric ozone distribution and general circulation patterns in the troposphere and aim to investigate the causal relationship between them, including the practical side of the influence of stratospheric ozone on tropospheric medium-range weather and regional climate. Analysis of several decades of observational data, which has been performed at the A.I. Voeikov Main Geophysical Observatory, suggests a clear relation between the stratospheric ozone distribution, upper stratospheric temperature field and planetary-scale air-masses boundaries in the troposphere [1]. Furthermore, it has been shown that each global air-mass, which can be attributed to the corresponding circulation cell in a conceptual model of tropospheric general circulation, has a distinct "regime" of ozone vertical distribution in the stratosphere [1-3]. Proceeding from atmospheric reanalyses combined with satellite and ground-based observations, we study time evolution of the upper-level frontal zones (stationary fronts) with the relevant jet streams, which can be treated as boundaries of global air-masses, in connection with the tropopause height and distribution of ozone in the stratosphere. For that, we develop an algorithm for automated identification of jet streams, stationary fronts and tropopause surface from gridded data (reanalyses or modelling results), and apply it for several cases associated with rapid changes in the stratospheric temperature and ozone fields, including SSW events over Eastern Siberia. Aiming to study the causal relationship between the features of tropospheric circulation and changes in the stratospheric ozone field, we estimate the time lag between these categories of processes on different time scales. Finally, we discuss the possibility to use the elementary circulation mechanisms classification (by B.L. Dzerdzeevski) in connection with analysis of the stratospheric ozone field and the relevant stratosphere

  6. Matrix-free constructions of circulant and block circulant preconditioners

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Chao; Ng, Esmond G.; Penczek, Pawel A.

    2001-12-01

    A framework for constructing circulant and block circulant preconditioners (C) for a symmetric linear system Ax=b arising from certain signal and image processing applications is presented in this paper. The proposed scheme does not make explicit use of matrix elements of A. It is ideal for applications in which A only exists in the form of a matrix vector multiplication routine, and in which the process of extracting matrix elements of A is costly. The proposed algorithm takes advantage of the fact that for many linear systems arising from signal or image processing applications, eigenvectors of A can be well represented by a small number of Fourier modes. Therefore, the construction of C can be carried out in the frequency domain by carefully choosing its eigenvalues so that the condition number of C{sup T} AC can be reduced significantly. We illustrate how to construct the spectrum of C in a way such that the smallest eigenvalues of C{sup T} AC overlaps with those of A extremely well while the largest eigenvalues of C{sup T} AC are smaller than those of A by several orders of magnitude. Numerical examples are provided to demonstrate the effectiveness of the preconditioner on accelerating the solution of linear systems arising from image reconstruction application.

  7. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project. Annual report, 1988

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    This Annual Report on Colorado-Ute Electric Association`s NUCLA Circulating Fluidized Bed (CFB) Demonstration Program covers the period from February 1987 through December 1988. The outline for presentation in this report includes a summary of unit operations along with individual sections covering progress in study plan areas that commenced during this reporting period. These include cold-mode shakedown and calibration, plant commercial performance statistics, unit start-up (cold), coal and limestone preparation and handling, ash handling system performance and operating experience, tubular air heater, baghouse operation and performance, materials monitoring, and reliability monitoring. During this reporting period, the coal-mode shakedown and calibration plan was completed. (VC)

  8. Cylindrical air flow reversal barrier

    Energy Technology Data Exchange (ETDEWEB)

    Woznica, C.; Rodziewicz, M.

    1988-06-01

    Describes an innovative design introduced in the ZMP mine in Zory for quick reversal of ventilation air flow. Geologic mining conditions at the 705 m deep horizon, where the barrier was built, are described. According to the design used until now, a reversal system consisted of safety barriers, ventilation air locks, a ventilation bridge and stopping needed in case of a fire when air flow direction must be reversed. Nine air locks and an expensive concrete ventilation bridge were needed and the air locks had to be operated at 8 points of the region to effect reversal. The new design consists of a 2-storey cylindrical barrier which also fulfills the function of a ventilation bridge. It can be manually or remotely operated by a mechanical or pneumatic system. Tests showed that the new barrier permits immediate air flow reversal while retaining 60% of the original air, which is important in the case of fire and methane hazards. It permits improved seam panelling and splitting of pillars and brings an economy of about 40 million zlotys in construction cost. Design and operation of the barrier is illustrated and ventilation air circulation is explained. 7 figs.

  9. Protective supplied breathing air garment

    Science.gov (United States)

    Childers, Edward L.; von Hortenau, Erik F.

    1984-07-10

    A breathing air garment for isolating a wearer from hostile environments containing toxins or irritants includes a suit and a separate head protective enclosure or hood engaging a suit collar in sealing attachment. The hood and suit collar are cylindrically shaped and dimensioned to enable the wearer to withdraw his hands from the suit sleeves to perform manual tasks within the hood interior. Breathing air is supplied from an external air line with an air delivery hose attached to the hood interior. The hose feeds air into an annular halo-like fiber-filled plenum having spaced discharge orifices attached to the hood top wall. A plurality of air exhaust/check valves located at the suit extremities cooperate with the hood air delivery system to provide a cooling flow of circulating air from the hood throughout the suit interior. A suit entry seal provided on the suit rear torso panel permits access into the suit and is sealed with an adhesive sealing flap.

  10. Autonomic Regulation of Splanchnic Circulation

    Directory of Open Access Journals (Sweden)

    Kathleen A Fraser

    1991-01-01

    Full Text Available The role of the autonomic nervous system in circulatory regulation of the splanchnic organs (stomach, small intestine, colon, liver, pancreas and spleen is reviewed. In general, the sympathetic nervous system is primarily involved in vasoconstriction, while the parasympathetic contributes to vasodilation. Vasoconstriction in the splanchnic circulation appears to be mediated by alpha-2 receptors and vasodilation by activation of primary afferent nerves with subsequent release of vasodilatory peptides, or by stimulation of beta-adrenergic receptors. As well, an important function of the autonomic nervous system is to provide a mechanism by which splanchnic vascular reserve can be mobilized during stress to maintain overall cardiovascular homeostasis.

  11. Acute management of vascular air embolism

    Directory of Open Access Journals (Sweden)

    Shaikh Nissar

    2009-01-01

    Full Text Available Vascular air embolism (VAE is known since early nineteenth century. It is the entrainment of air or gas from operative field or other communications into the venous or arterial vasculature. Exact incidence of VAE is difficult to estimate. High risk surgeries for VAE are sitting position and posterior fossa neurosurgeries, cesarean section, laparoscopic, orthopedic, surgeries invasive procedures, pulmonary overpressure syndrome, and decompression syndrome. Risk factors for VAE are operative site 5 cm  above the heart, creation of pressure gradient which will facilitate entry of air into the circulation, orogenital sex during pregnancy, rapid ascent in scuba (self contained underwater breathing apparatus divers and barotrauma or chest trauma. Large bolus of air can lead to right ventricular air lock and immediate fatality. In up to 35% patient, the foramen ovale is patent which can cause paradoxical arterial air embolism. VAE affects cardiovascular, pulmonary and central nervous system. High index of clinical suspicion is must to diagnose VAE. The transesophgeal echocardiography is the most sensitive device which will detect smallest amount of air in the circulation. Treatment of VAE is to prevent further entrainment of air, reduce the volume of air entrained and haemodynamic support. Mortality of VAE ranges from 48 to 80%. VAE can be prevented significantly by proper positioning during surgery, optimal hydration, avoiding use of nitrous oxide, meticulous care during insertion, removal of central venous catheter, proper guidance, and training of scuba divers.

  12. Intestinal circulation during inhalation anesthesia

    Energy Technology Data Exchange (ETDEWEB)

    Tverskoy, M.; Gelman, S.; Fowler, K.C.; Bradley, E.L.

    1985-04-01

    This study was designed to evaluate the influence of inhalational agents on the intestinal circulation in an isolated loop preparation. Sixty dogs were studied, using three intestinal segments from each dog. Selected intestinal segments were pumped with aortic blood at a constant pressure of 100 mmHg. A mixture of /sub 86/Rb and 9-microns spheres labeled with /sup 141/Ce was injected into the arterial cannula supplying the intestinal loop, while mesenteric venous blood was collected for activity counting. A very strong and significant correlation was found between rubidium clearance and microsphere entrapment (r = 0.97, P less than 0.0001). Nitrous oxide anesthesia was accompanied by a higher vascular resistance (VR), lower flow (F), rubidium clearance (Cl-Rb), and microspheres entrapment (Cl-Sph) than pentobarbital anesthesia, indicating that the vascular bed in the intestinal segment was constricted and flow (total and nutritive) decreased. Halothane, enflurane, and isoflurane anesthesia were accompanied by a much lower arteriovenous oxygen content difference (AVDO/sub 2/) and oxygen uptake than pentobarbital or nitrous oxide. Compared with pentobarbital, enflurane anesthesia was not accompanied by marked differences in VR, F, Cl-Rb, and Cl-Sph; halothane at 2 MAC decreased VR and increased F and Cl-Rb while isoflurane increased VR and decreased F. alpha-Adrenoceptor blockade with phentolamine (1 mg . kg-1) abolished isoflurane-induced vasoconstriction, suggesting that the increase in VR was mediated via circulating catecholamines.

  13. CIRCULATING MOVING BED COMBUSTION PROOF OF CONCEPT

    Energy Technology Data Exchange (ETDEWEB)

    Jukkola, Glen

    2010-06-30

    Circulating Moving Bed (CMB) combustion technology has its roots in traditional circulating fluidized bed technology and involves a novel method of solid fuel combustion and heat transfer. CMB technology represents a step change in improved performance and cost relative to conventional PC and FBC boilers. The CMB heat exchanger preheats the energy cycle working fluid, steam or air, to the high temperature levels required in systems for advanced power generation. Unique features of the CMB are the reduction of the heat transfer surfaces by about 60% as a result of the enhanced heat transfer rates, flexibility of operation, and about 30% lower cost over existing technology. The CMB Phase I project ran from July 2001 through March 2003. Its objective was to continue development of the CMB technology with a series of proof of concept tests. The tests were conducted at a scale that provided design data for scale up to a demonstration plant. These objectives were met by conducting a series of experiments in ALSTOM Power’s Multi-use Test Facility (MTF). The MTF was modified to operate under CMB conditions of commercial interest. The objective of the tests were to evaluate gas-to-solids heat transfer in the upper furnace, assess agglomeration in the high temperature CMB bubbling bed, and evaluate solids-to-tube heat transfer in the moving bed heat exchanger. The Phase I program results showed that there are still some significant technical uncertainties that needed to be resolved before the technology can be confidently scaled up for a successful demonstration plant design. Work remained in three primary areas: • scale up of gas to solid heat transfer • high temperature finned surface design • the overall requirements of mechanical and process design. The CMB Phase II workscope built upon the results of Phase I and specifically addressed the remaining technical uncertainties. It included a scaled MTF heat transfer test to provide the necessary data to scale up gas

  14. Modeling biomass gasification in circulating fluidized beds

    Science.gov (United States)

    Miao, Qi

    In this thesis, the modeling of biomass gasification in circulating fluidized beds was studied. The hydrodynamics of a circulating fluidized bed operating on biomass particles were first investigated, both experimentally and numerically. Then a comprehensive mathematical model was presented to predict the overall performance of a 1.2 MWe biomass gasification and power generation plant. A sensitivity analysis was conducted to test its response to several gasifier operating conditions. The model was validated using the experimental results obtained from the plant and two other circulating fluidized bed biomass gasifiers (CFBBGs). Finally, an ASPEN PLUS simulation model of biomass gasification was presented based on minimization of the Gibbs free energy of the reaction system at chemical equilibrium. Hydrodynamics plays a crucial role in defining the performance of gas-solid circulating fluidized beds (CFBs). A 2-dimensional mathematical model was developed considering the hydrodynamic behavior of CFB gasifiers. In the modeling, the CFB riser was divided into two regions: a dense region at the bottom and a dilute region at the top of the riser. Kunii and Levenspiel (1991)'s model was adopted to express the vertical solids distribution with some other assumptions. Radial distributions of bed voidage were taken into account in the upper zone by using Zhang et al. (1991)'s correlation. For model validation purposes, a cold model CFB was employed, in which sawdust was transported with air as the fluidizing agent. A comprehensive mathematical model was developed to predict the overall performance of a 1.2 MWe biomass gasification and power generation demonstration plant in China. Hydrodynamics as well as chemical reaction kinetics were considered. The fluidized bed riser was divided into two distinct sections: (a) a dense region at the bottom of the bed where biomass undergoes mainly heterogeneous reactions and (b) a dilute region at the top where most of homogeneous

  15. Oxy-combustion of biomass in a circulating fluidized bed

    Science.gov (United States)

    Kosowska-Golachowska, Monika; Kijo-Kleczkowska, Agnieszka; Luckos, Adam; Wolski, Krzysztof; Musiał, Tomasz

    2016-03-01

    The objective of this study was to investigate combustion characteristics of biomass (willow, Salix viminalis) burnt in air and O2/CO2 mixtures in a circulating fluidized bed (CFB). Air and oxy-combustion characteristics of wooden biomass in CFB were supplemented by the thermogravimetric and differential thermal analyses (TGA/DTA). The results of conducted CFB and TGA tests show that the composition of the oxidizing atmosphere strongly influences the combustion process of biomass fuels. Replacing N2 in the combustion environment by CO2 caused slight delay (higher ignition temperature and lower maximum mass loss rate) in the combustion of wooden biomass. The combustion process in O2/CO2 mixtures at 30% and 40% O2 is faster and shorter than that at lower O2 concentrations.

  16. Oxy-combustion of biomass in a circulating fluidized bed

    Directory of Open Access Journals (Sweden)

    Kosowska-Golachowska Monika

    2016-03-01

    Full Text Available The objective of this study was to investigate combustion characteristics of biomass (willow, Salix viminalis burnt in air and O2/CO2 mixtures in a circulating fluidized bed (CFB. Air and oxy-combustion characteristics of wooden biomass in CFB were supplemented by the thermogravimetric and differential thermal analyses (TGA/DTA. The results of conducted CFB and TGA tests show that the composition of the oxidizing atmosphere strongly influences the combustion process of biomass fuels. Replacing N2 in the combustion environment by CO2 caused slight delay (higher ignition temperature and lower maximum mass loss rate in the combustion of wooden biomass. The combustion process in O2/CO2 mixtures at 30% and 40% O2 is faster and shorter than that at lower O2 concentrations.

  17. A blood circulation model for reference man

    Energy Technology Data Exchange (ETDEWEB)

    Leggett, R.W.; Eckerman, K.F. [Oak Ridge National Lab., TN (United States). Health Sciences Research Div.; Williams, L.R. [Indiana Univ., South Bend, IN (United States). Div. of Liberal Arts and Sciences

    1999-01-01

    This paper describes a dynamic blood circulation model that predicts the movement and gradual dispersal of a bolus of material in the circulation after its intravascular injection into an adult human. The main purpose of the model is to improve the dosimetry of internally deposited radionuclides that decay in the circulation to a significant extent. The total blood volume is partitioned into the blood contents of 24 separate organs or tissues, right heart chambers, left heart chambers, pulmonary circulation, arterial outflow to the systemic tissues (aorta and large arteries), and venous return from the systemic tissues (large veins). As a compromise between physical reality and computational simplicity, the circulation of blood is viewed as a system of first-order transfers between blood pools, with the delay time depending on the mean transit time across the pool. The model allows consideration of incomplete, tissue-dependent extraction of material during passage through the circulation and return of material from tissues to plasma.

  18. A Note on the South China Sea Shallow Interocean Circulation

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The existing estimates of the volume transport from the Pacific Ocean to the South China Sea are summarized, showing an annual mean westward transport, with the Taiwan Strait outflow subtracted, of 3.5±2.0 Sv (1 Sv=106 m3 s-1). Results of a global ocean circulation model show an annual mean transport of 3.9 Sv from the Pacific to the Indian Ocean through the South China Sea. The boreal winter transport is larger and exhibits a South China Sea branch of the Pacific-to-Indian Ocean throughflow, which originates from the western Philippine Sea toward the Indonesian Seas through the South China Sea, as well as through the Karimata and Mindoro Straits. The southwestward current near the continental slope of the northern South China Sea is shown to be a combination of this branch and the interior circulation gyre.This winter branch can be confirmed by trajectories of satellite-tracked drifters, which clearly show a flow from the Luz6n Strait to the Karimata Strait in winter. In summer, the flow in the Karimata Strait is reversed. Numerical model results indicate that the Pacific water can enter the South China Sea and exit toward the Sulu Sea, but no observational evidence is available. The roles of the throughflow branch in the circulation, water properties and air-sea exchange of the South China Sea, and in enhancing and regulating the volume transport and reducing the heat transport of the Indonesian Throughflow, are discussed.

  19. The relationship between the thermohaline circulation and climate variability

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The long-term integration with the Global Ocean-Atmosphere-Land System model of the State Key Laboratory of Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics(IAP), Chinese Academy of Sciences has been used in the investigations on the relationship between the thermohaline circulation and climate variability. The results show that the strength of the North Atlantic Thermohaline circulation (THC) is negatively correlated with the North Atlantic Oscillation (NAO). Based on this kind of relationship, and also the instrument-measured climate record such as air pressure and sea surface temperature, the activity of the thermohaline circulation during the 20th century has been evaluated. The inferred variations of the strength of the THC is that, during two multi-decadal periods of 1867-1903 and 1934-1972, the THC is estimated to have been running stronger, whereas during the two periods of 1904-1933 and 1973-1994, it appears to have been weaker.

  20. Development of a hydraulic model of the human systemic circulation

    Science.gov (United States)

    Sharp, M. K.; Dharmalingham, R. K.

    1999-01-01

    Physical and numeric models of the human circulation are constructed for a number of objectives, including studies and training in physiologic control, interpretation of clinical observations, and testing of prosthetic cardiovascular devices. For many of these purposes it is important to quantitatively validate the dynamic response of the models in terms of the input impedance (Z = oscillatory pressure/oscillatory flow). To address this need, the authors developed an improved physical model. Using a computer study, the authors first identified the configuration of lumped parameter elements in a model of the systemic circulation; the result was a good match with human aortic input impedance with a minimum number of elements. Design, construction, and testing of a hydraulic model analogous to the computer model followed. Numeric results showed that a three element model with two resistors and one compliance produced reasonable matching without undue complication. The subsequent analogous hydraulic model included adjustable resistors incorporating a sliding plate to vary the flow area through a porous material and an adjustable compliance consisting of a variable-volume air chamber. The response of the hydraulic model compared favorably with other circulation models.

  1. Tropospheric circulation during the early twentieth century Arctic warming

    Science.gov (United States)

    Wegmann, Martin; Brönnimann, Stefan; Compo, Gilbert P.

    2016-06-01

    The early twentieth century Arctic warming (ETCAW) between 1920 and 1940 is an exceptional feature of climate variability in the last century. Its warming rate was only recently matched by recent warming in the region. Unlike recent warming largely attributable to anthropogenic radiative forcing, atmospheric warming during the ETCAW was strongest in the mid-troposphere and is believed to be triggered by an exceptional case of natural climate variability. Nevertheless, ultimate mechanisms and causes for the ETCAW are still under discussion. Here we use state of the art multi-member global circulation models, reanalysis and reconstruction datasets to investigate the internal atmospheric dynamics of the ETCAW. We investigate the role of boreal winter mid-tropospheric heat transport and circulation in providing the energy for the large scale warming. Analyzing sensible heat flux components and regional differences, climate models are not able to reproduce the heat flux evolution found in reanalysis and reconstruction datasets. These datasets show an increase of stationary eddy heat flux and a decrease of transient eddy heat flux during the ETCAW. Moreover, tropospheric circulation analysis reveals the important role of both the Atlantic and the Pacific sectors in the convergence of southerly air masses into the Arctic during the warming event. Subsequently, it is suggested that the internal dynamics of the atmosphere played a major role in the formation in the ETCAW.

  2. Linear thermal circulator based on Coriolis forces.

    Science.gov (United States)

    Li, Huanan; Kottos, Tsampikos

    2015-02-01

    We show that the presence of a Coriolis force in a rotating linear lattice imposes a nonreciprocal propagation of the phononic heat carriers. Using this effect we propose the concept of Coriolis linear thermal circulator which can control the circulation of a heat current. A simple model of three coupled harmonic masses on a rotating platform permits us to demonstrate giant circulating rectification effects for moderate values of the angular velocities of the platform.

  3. A brief etymology of the collateral circulation.

    Science.gov (United States)

    Faber, James E; Chilian, William M; Deindl, Elisabeth; van Royen, Niels; Simons, Michael

    2014-09-01

    It is well known that the protective capacity of the collateral circulation falls short in many individuals with ischemic disease of the heart, brain, and lower extremities. In the past 15 years, opportunities created by molecular and genetic tools, together with disappointing outcomes in many angiogenic trials, have led to a significant increase in the number of studies that focus on: understanding the basic biology of the collateral circulation; identifying the mechanisms that limit the collateral circulation's capacity in many individuals; devising methods to measure collateral extent, which has been found to vary widely among individuals; and developing treatments to increase collateral blood flow in obstructive disease. Unfortunately, accompanying this increase in reports has been a proliferation of vague terms used to describe the disposition and behavior of this unique circulation, as well as the increasing misuse of well-ensconced ones by new (and old) students of collateral circulation. With this in mind, we provide a brief glossary of readily understandable terms to denote the formation, adaptive growth, and maladaptive rarefaction of collateral circulation. We also propose terminology for several newly discovered processes that occur in the collateral circulation. Finally, we include terms used to describe vessels that are sometimes confused with collaterals, as well as terms describing processes active in the general arterial-venous circulation when ischemic conditions engage the collateral circulation. We hope this brief review will help unify the terminology used in collateral research.

  4. Role of Circulating Fibrocytes in Cardiac Fibrosis

    Institute of Scientific and Technical Information of China (English)

    Rong-Jie Lin; Zi-Zhuo Su; Shu-Min Liang; Yu-Yang Chen; Xiao-Rong Shu; Ru-Qiong Nie; Jing-Feng Wang

    2016-01-01

    Objective: It is revealed that circulating fibrocytes are elevated in patients/animals with cardiac fibrosis, and this review aims to provide an introduction to circulating fibrocytes and their role in cardiac fibrosis.Data Sources: This review is based on the data from 1994 to present obtained from PubMed.The search terms were "circulating fibrocytes" and "cardiac fibrosis".Study Selection: Articles and critical reviews, which are related to circulating fibrocytes and cardiac fibrosis, were selected.Results: Circulating fibrocytes, which are derived from hematopoietic stem cells, represent a subset of peripheral blood mononuclear cells exhibiting mixed morphological and molecular characteristics ofhematopoietic and mesenchymal cells (CD34+/CD45+/collagen I+).They can produce extracellular matrix and many cytokines.It is shown that circulating fibrocytes participate in many fibrotic diseases, including cardiac fibrosis.Evidence accumulated in recent years shows that aging individuals and patients with hypertension, heart failure, coronary heart disease, and atrial fibrillation have more circulating fibrocytes in peripheral blood and/or heart tissue, and this elevation of circulating fibrocytes is correlated with the degree of fibrosis in the hearts.Conclusions: Circulating fibrocytes are effector cells in cardiac fibrosis.

  5. The Rank of Integral Circulant Graphs

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hou-qing

    2014-01-01

    A graph is called an integral graph if it has an integral spectrum i.e., all eigen-values are integers. A graph is called circulant graph if it is Cayley graph on the circulant group, i.e., its adjacency matrix is circulant. The rank of a graph is defined to be the rank of its adjacency matrix. This importance of the rank, due to applications in physics, chemistry and combinatorics. In this paper, using Ramanujan sums, we study the rank of integral circulant graphs and gave some simple computational formulas for the rank and provide an example which shows the formula is sharp.

  6. Role of Circulating Fibrocytes in Cardiac Fibrosis

    Science.gov (United States)

    Lin, Rong-Jie; Su, Zi-Zhuo; Liang, Shu-Min; Chen, Yu-Yang; Shu, Xiao-Rong; Nie, Ru-Qiong; Wang, Jing-Feng; Xie, Shuang-Lun

    2016-01-01

    Objective: It is revealed that circulating fibrocytes are elevated in patients/animals with cardiac fibrosis, and this review aims to provide an introduction to circulating fibrocytes and their role in cardiac fibrosis. Data Sources: This review is based on the data from 1994 to present obtained from PubMed. The search terms were “circulating fibrocytes” and “cardiac fibrosis”. Study Selection: Articles and critical reviews, which are related to circulating fibrocytes and cardiac fibrosis, were selected. Results: Circulating fibrocytes, which are derived from hematopoietic stem cells, represent a subset of peripheral blood mononuclear cells exhibiting mixed morphological and molecular characteristics of hematopoietic and mesenchymal cells (CD34+/CD45+/collagen I+). They can produce extracellular matrix and many cytokines. It is shown that circulating fibrocytes participate in many fibrotic diseases, including cardiac fibrosis. Evidence accumulated in recent years shows that aging individuals and patients with hypertension, heart failure, coronary heart disease, and atrial fibrillation have more circulating fibrocytes in peripheral blood and/or heart tissue, and this elevation of circulating fibrocytes is correlated with the degree of fibrosis in the hearts. Conclusions: Circulating fibrocytes are effector cells in cardiac fibrosis. PMID:26831236

  7. Inflammatory response and extracorporeal circulation.

    Science.gov (United States)

    Kraft, Florian; Schmidt, Christoph; Van Aken, Hugo; Zarbock, Alexander

    2015-06-01

    Patients undergoing cardiac surgery with extracorporeal circulation (EC) frequently develop a systemic inflammatory response syndrome. Surgical trauma, ischaemia-reperfusion injury, endotoxaemia and blood contact to nonendothelial circuit compounds promote the activation of coagulation pathways, complement factors and a cellular immune response. This review discusses the multiple pathways leading to endothelial cell activation, neutrophil recruitment and production of reactive oxygen species and nitric oxide. All these factors may induce cellular damage and subsequent organ injury. Multiple organ dysfunction after cardiac surgery with EC is associated with an increased morbidity and mortality. In addition to the pathogenesis of organ dysfunction after EC, this review deals with different therapeutic interventions aiming to alleviate the inflammatory response and consequently multiple organ dysfunction after cardiac surgery.

  8. Linear system identification of a cold flow circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Panday, R [West Virginia Univ., Morgantown, WV (United States); Woerner, B D [West Virginia Univ., Morgantown, WV (United States); Ludlow, J C [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Shadle, L J [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Boyle, E J [National Energy Technology Lab. (NETL), Morgantown, WV (United States)

    2009-02-01

    Knowledge of the solids circulation rate (SCR) is essential to the control and improved performance of a circulating fluidized bed system. In the present work, the noise model is derived using the prediction error method considering process and measurement noises acting on the cold flow circulating fluidized bed (CFCFB) with a cork particulate material. The outputs of the initial model are the total pressure drop across the riser, the pressure drop across the crossover, the pressure drop across the primary cyclone, the total pressure drop across the stand-pipe, the pressure drop across the loop seal, and the SCR. The stochastic estimate of SCR is determined from the noise model using the stochastic pressure drop estimates. The deterministic estimate is obtained through the inputs taken as move air flow, riser aeration, and loop seal fluidization air that are all independent variables of the given setup and under the control of the user. The theory has been developed to convert a complete blackbox model to a grey box model through the output-to-state transformation such that both the models of the CFCFB consists of all these output variables as the states of the system, and only pressure drops across the system as the output measurements. Thus, the final models do not include any fictitious terms and they are defined only in terms of physical parameters of the given system. Both components of SCR are separately analysed. The combined SCR response of both the noise model and deterministic model is compared with the validation data set of this state variable in terms of modelfit, and the results are shown.

  9. PRELIMINARY STUDY ON CIRCULATION HEIGHT OF CIRCULATION FLOW WITH THE HORIZONTAL AXIS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, the relationship between circulation heights of circulation flow with horizontal axis and incident flow conditions as well as side slope angles of trenches was systematically analyzed on the basis of the velocity distribution data observed in a series of model tests in a flume, and the related formula for the circulation height was proposed. Moreover, the variation of circulation flow intensity was also analyzed.

  10. Optimization of recirculating laminar air flow in operating room air conditioning systems

    Directory of Open Access Journals (Sweden)

    Enver Yalcin

    2016-04-01

    Full Text Available The laminar flow air-conditioning system with 100% fresh air is used in almost all operating rooms without discrimination in Turkey. The laminar flow device which is working with 100% fresh air should be absolutely used in Type 1A operating rooms. However, there is not mandatory to use of 100% fresh air for Type 1B defined as places performed simpler operation. Compared with recirculating laminar flow, energy needs of the laminar flow with 100 % fresh air has been emerged about 40% more than re-circulated air flow. Therefore, when a recirculating laminar flow device is operated instead of laminar flow system with 100% fresh air in the Type 1B operating room, annual energy consumption will be reduced. In this study, in an operating room with recirculating laminar flow, optimal conditions have been investigated in order to obtain laminar flow form by analyzing velocity distributions at various supply velocities by using computational fluid dynamics method (CFD.

  11. GENERATOR VIBRATION FAULT DIAGNOSIS METHOD BASED ON ROTOR VIBRATION AND STATOR WINDING PARALLEL BRANCHES CIRCULATING CURRENT CHARACTERISTICS

    Institute of Scientific and Technical Information of China (English)

    Wan Shuting; Li Heming; Li Yonggang; Tang Guiji

    2005-01-01

    Rotor vibration characteristics are first analyzed, which are that the rotor vibration of fundamental frequency will increase due to rotor winding inter-turn short circuit fault, air-gap dynamic eccentricity fault, or imbalance fault, and the vibration of the second frequency will increase when the air-gap static eccentricity fault occurs. Next, the characteristics of the stator winding parallel branches circulating current are analyzed, which are that the second harmonics circulating current will increase when the rotor winding inter-turn short circuit fault occurs, and the fundamental circulating current will increase when the air-gap eccentricity fault occurs, neither being strongly affected by the imbalance fault. Considering the differences of the rotor vibration and circulating current characteristics caused by different rotor faults, a method of generator vibration fault diagnosis, based on rotor vibration and circulating current characteristics, is developed. Finally, the rotor vibration and circulating current of a type SDF-9 generator is measured in the laboratory to verify the theoretical analysis presented above.

  12. Dispensing with the DVD Circulation Dilemma

    Science.gov (United States)

    Ellis, Mark

    2008-01-01

    Richmond Public Library (RPL) is a four-branch suburban library with the highest per capita circulation of any comparable library in Canada. While DVDs naturally fit into RPL's emphasis on popular material, circulating them using the standard model proved problematic: Long hold queues built up, DVDs idled on the hold shelves, and the circulation…

  13. Space-Time radar waveforms: circulating codes

    NARCIS (Netherlands)

    Babur, G.; Aubry, P.; Le Chevalier, F.

    2013-01-01

    This paper describes a concept of the circulating codes covering the whole class of the space-time codes. The circulating codes do not narrow the radiated pattern of the antenna array, thus providing a wide angular coverage, possibly tunable. In turn, the beam-forming on transmit is achievable by me

  14. On So's conjecture for integral circulant graphs

    Directory of Open Access Journals (Sweden)

    J.W. Sander

    2015-04-01

    According to a conjecture of {\\sc So} two integral circulant graphs are isomorphic if and only if they are isospectral, i.e. they have the same eigenvalues (counted with multiplicities. We prove a weaker form of this conjecture, namely, that two integral circulant graphs with multiplicative divisor sets are isomorphic if and only if their spectral vectors coincide.

  15. Physiology of the fetal and transitional circulation.

    Science.gov (United States)

    Finnemore, Anna; Groves, Alan

    2015-08-01

    The fetal circulation is an entirely transient event, not replicated at any point in later life, and functionally distinct from the pediatric and adult circulations. Understanding of the physiology of the fetal circulation is vital for accurate interpretation of hemodynamic assessments in utero, but also for management of circulatory compromise in premature infants, who begin extrauterine life before the fetal circulation has finished its maturation. This review summarizes the key classical components of circulatory physiology, as well as some of the newer concepts of physiology that have been appreciated in recent years. The immature circulation has significantly altered function in all aspects of circulatory physiology. The mechanisms and significance of these differences are also discussed, as is the impact of these alterations on the circulatory transition of infants born prematurely.

  16. Model-free adaptive control of supercritical circulating fluidized-bed boilers

    Science.gov (United States)

    Cheng, George Shu-Xing; Mulkey, Steven L

    2014-12-16

    A novel 3-Input-3-Output (3.times.3) Fuel-Air Ratio Model-Free Adaptive (MFA) controller is introduced, which can effectively control key process variables including Bed Temperature, Excess O2, and Furnace Negative Pressure of combustion processes of advanced boilers. A novel 7-input-7-output (7.times.7) MFA control system is also described for controlling a combined 3-Input-3-Output (3.times.3) process of Boiler-Turbine-Generator (BTG) units and a 5.times.5 CFB combustion process of advanced boilers. Those boilers include Circulating Fluidized-Bed (CFB) Boilers and Once-Through Supercritical Circulating Fluidized-Bed (OTSC CFB) Boilers.

  17. Dynamics of Clouds and Mesoscale Circulations over the Maritime Continent

    Science.gov (United States)

    Jin, Y.; Wang, S.; Xian, P.; Reid, J. S.; Nachamkin, J.

    2010-12-01

    In recent decades Southeast Asia (SEA) has seen rapid economic growth as well as increased biomass burning, resulting in high air pollution levels and reduced air qual-ity. At the same time clouds often prevent accurate air-quality monitoring and analysis using satellite observations. The Seven SouthEast Asian Studies (7SEAS) field campaign currently underway over SEA provides an unprecedented opportunity to study the com-plex interplay between aerosol and clouds. 7SEAS is a comprehensive interdisciplinary atmospheric sciences program through international partnership of NASA, NRL, ONR and seven local institutions including those from Indonesia, Malaysia, the Philippines, Singapore, Taiwan, Thailand, and Vietnam. While the original goal of 7SEAS is to iso-late the impacts of aerosol particles on weather and the environment, it is recognized that better understanding of SEA meteorological conditions, especially those associated with cloud formation and evolution, is critical to the success of the campaign. In this study we attempt to gain more insight into the dynamic and physical processes associated with low level clouds and atmospheric circulation at the regional scale over SEA, using the Navy’s Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS® ), a regional forecast model in operation at FNMOC since 1998. This effort comprises two main components. First, multiple-years of COAMPS operational forecasts over SEA are analyzed for basic climatology of atmospheric fea-tures. Second, mesoscale circulation and cloud properties are simulated at relatively higher resolution (15-km) for selected periods in the Gulf of Tonkin and adjacent coastal areas. Simulation results are compared to MODIS cloud observations and local sound-ings obtained during 7SEAS for model verifications. Atmospheric boundary layer proc-esses are examined in relation to spatial and temporal variations of cloud fields. The cur-rent work serves as an important step toward improving our

  18. Small Break Air Ingress Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Chang Oh; Eung Soo Kim

    2011-09-01

    The small break air-ingress experiment, described in this report, is designed to investigate air-ingress phenomena postulated to occur in pipes in a very high temperature gas-cooled reactor (VHTRs). During this experiment, air-ingress rates were measured for various flow and break conditions through small holes drilled into a pipe of the experimental apparatus. The holes were drilled at right angles to the pipe wall such that a direction vector drawn from the pipe centerline to the center of each hole was at right angles with respect to the pipe centerline. Thus the orientation of each hole was obtained by measuring the included angle between the direction vector of each hole with respect to a reference line anchored on the pipe centerline and pointing in the direction of the gravitational force. Using this reference system, the influence of several important parameters on the air ingress flow rate were measured including break orientation, break size, and flow velocity . The approach used to study the influence of these parameters on air ingress is based on measuring the changes in oxygen concentrations at various locations in the helium flow circulation system as a function of time using oxygen sensors (or detectors) to estimate the air-ingress rates through the holes. The test-section is constructed of a stainless steel pipe which had small holes drilled at the desired locations.

  19. Interannual variability of the Adriatic Sea circulation

    Science.gov (United States)

    Beg Paklar, Gordana; Sepic, Jadranka; Grbec, Branka; Dzoic, Tomislav; Kovac, Zarko; Ivatek-Sahdan, Stjepan

    2016-04-01

    The Regional Ocean Modeling System (ROMS) was implemented in order to reproduce interannual variability of the Adriatic Sea circulation. Simulations and model result analysis were performed for a three-year period from 1st January 2011 to 31st December 2013. ROMS model run was forced with realistic atmospheric fields obtained from meteorological model Aladin, climatological river discharges, tides and Mediterranean circulation imposed at the southern open boundary. Atmospheric forcing included momentum, heat and water fluxes calculated interactively from the Aladin surface fields during ROMS model simulations. Model results were compared with available CTD and ADCP measurements and discussed in the light of the climatological circulation and thermohaline properties of the Adriatic Sea and its coastal areas. Interannual variability in the Adriatic circulation is related to the prevailing atmospheric conditions, changes in the hydrological conditions and water mass exchange at the Otranto Strait. Basic features of the Adriatic circulation - basin-wide cyclonic circulation with several embedded smaller cyclonic gyres around main pits - are well reproduced by ROMS model. Modelled temperatures and salinities are within corresponding seasonal intervals, although measured profiles generally indicate stronger stratification than modelled ones. Summer circulation in 2011 with current reversal obtained along the eastern Adriatic coast was related to the sampling results of the early fish stages as well as to ARGO drifter movements. Simulated fields from the Adriatic scale model were used to prescribe the initial and open boundary conditions for the interannual simulation in the middle Adriatic coastal domain.

  20. Olive cake combustion in a circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Huseyin Topal; Aysel T. Atimtay; Ali Durmaz [Gazi University, Ankara (Turkey). Department of Mechanical Engineering, Engineering and Architecture Faculty

    2003-06-01

    In this study, a circulating fluidized bed of 125 mm diameter and 1800 mm height was used to find the combustion characteristics of olive cake (OC) produced in Turkey. A lignite coal that is most widely used in Turkey was also burned in the same combustor. The combustion experiments were carried out with various excess air ratios. The excess air ratio, {lambda} has been changed between 1.1 and 2.16. Temperature distribution along the bed was measured with thermocouples. On-line concentrations of O{sub 2}, SO{sub 2}, CO{sub 2}, CO, NOx and total hydrocarbons were measured in the flue gas. Combustion efficiencies of OC and lignite coal are calculated, and the optimum conditions for operating parameters are discussed. The combustion efficiency of OC changes between 82.25 and 98.66% depending on the excess air ratio. There is a sharp decrease observed in the combustion losses due to hydrocarbons and CO as the excess air ratio increases. The minimum emissions are observed at {lambda} = 1.35. Combustion losses due to unburned carbon in the bed material do not exceed 1.4 wt% for OC and 1.85 wt% for coal. The combustion efficiency for coal changes between 82.25 and 98.66% for various excess air ratios used in the study. The ash analysis for OC is carried out to find the suitability of OC ash to be used as fertilizer. The ash does not contain any hazardous metal. 7 refs., 10 figs., 6 tabs.

  1. Circulating miRNA and cancer diagnosis

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    miRNAs are a class of small RNA molecules with regulatory function, and play an important role in tumor development and progression. It has been demonstrated that tumor-derived miRNAs exist in the circulating nucleic acids of cancer patients. This phenomenon implies that detection of the circulating miRNA may be an effective method for non-invasive diagnosis of cancer. In this review, we summarize the applications of the circulating miRNA as biomarkers in cancer diagnosis, as well as the latest research progress in this area.

  2. Combined air and water pollution control system

    Science.gov (United States)

    Wolverton, Billy C. (Inventor); Jarrell, Lamont (Inventor)

    1990-01-01

    A bioaquatic air pollution control system for controlling both water and atmospheric pollution is disclosed. The pollution control system includes an exhaust for directing polluted gases out of a furnace and a fluid circulating system which circulates fluid, such as waste water, from a source, past the furnace where the fluid flow entrains the pollutants from the furnace. The combined fluid and pollutants are then directed through a rock/plant/microbial filtering system. A suction pump pumps the treated waste water from the filter system past the exhaust to again entrain more pollutants from the furnace where they are combined with the fluid (waste water) and directed to the filter system.

  3. Zinc electrode and rechargeable zinc-air battery

    Science.gov (United States)

    Ross, Jr., Philip N.

    1989-01-01

    An improved zinc electrode is disclosed for a rechargeable zinc-air battery comprising an outer frame and a porous foam electrode support within the frame which is treated prior to the deposition of zinc thereon to inhibit the formation of zinc dendrites on the external surface thereof. The outer frame is provided with passageways for circulating an alkaline electrolyte through the treated zinc-coated porous foam. A novel rechargeable zinc-air battery system is also disclosed which utilizes the improved zinc electrode and further includes an alkaline electrolyte within said battery circulating through the passageways in the zinc electrode and an external electrolyte circulation means which has an electrolyte reservoir external to the battery case including filter means to filter solids out of the electrolyte as it circulates to the external reservoir and pump means for recirculating electrolyte from the external reservoir to the zinc electrode.

  4. Air Pollution

    Science.gov (United States)

    ... to view this content or go to source URL . What NIEHS is Doing on Air Pollution Who ... Junction Last Reviewed: February 06, 2017 This page URL: NIEHS website: https://www.niehs.nih.gov/ Email ...

  5. Interdecadal Change in the Connection Between Hadley Circulation and Winter Temperature in East Asia

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Based on NCEP/NCAR reanalysis data, the interdecadal variability of Hadley circulation (HC) and its association with East Asian temperature in winter are investigated. Results indicate that the Northern Hemisphere winter HC underwent apparent change in the 1970s, with transition occurring around 1976/77.Along with interdecadal variability of HC, its linkage to surface air temperature (SAT) in East Asia also varied decadally, from weak relations to strong relations. Such a change may be related to the interaction between HC and the atmospheric circulation system over the Philippines, which is associated with the East Asian winter monsoon (EAWM). Before the 1970s, the connection between HC and the anticyclonic circulation around the Philippines was insignificant, but after the late 1970s their linkage entered a strong regime. The intensification of this connection may therefore be responsible for the strong relations between HC and East Asian winter temperatures after the late 1970s.

  6. EOP MIT General Circulation Model (MITgcm)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data contains a regional implementation of the Massachusetts Institute of Technology general circulation model (MITgcm) at a 1-km spatial resolution for the...

  7. Head positioning for anterior circulation aneurysms microsurgery

    Directory of Open Access Journals (Sweden)

    Feres Chaddad-Neto

    2014-11-01

    Full Text Available Objective To study the ideal patient's head positioning for the anterior circulation aneurysms microsurgery. Method We divided the study in two parts. Firstly, 10 fresh cadaveric heads were positioned and dissected in order to ideally expose the anterior circulation aneurysm sites. Afterwards, 110 patients were submitted to anterior circulation aneurysms microsurgery. During the surgery, the patient's head was positioned accordingly to the aneurysm location and the results from the cadaveric study. The effectiveness of the position was noted. Results We could determine mainly two patterns for head positioning for the anterior circulation aneurysms. Conclusion The best surgical exposure is related to specific head positions. The proper angle of microscopic view may minimize neurovascular injury and brain retraction.

  8. Red Sea circulation during marine isotope stage 5e

    Science.gov (United States)

    Siccha, Michael; Biton, Eli; Gildor, Hezi

    2015-04-01

    We have employed a regional Massachusetts Institute of Technology oceanic general circulation model of the Red Sea to investigate its circulation during marine isotope stage (MIS) 5e, the peak of the last interglacial, approximately 125 ka before present. Compared to present-day conditions, MIS 5e was characterized by higher Northern Hemisphere summer insolation, accompanied by increases in air temperature of more than 2°C and global sea level approximately 8 m higher than today. As a consequence of the increased seasonality, intensified monsoonal conditions with increased winds, rainfall, and humidity in the Red Sea region are evident in speleothem records and supported by model simulations. To assess the dominant factors responsible for the observed changes, we conducted several sensitivity experiments in which the MIS 5 boundary conditions or forcing parameters were used individually. Overall, our model simulation for the last interglacial maximum reconstructs a Red Sea that is colder, less ventilated and probably more oligotrophic than at present day. The largest alteration in Red Sea circulation and properties was found for the simulation of the northward displacement and intensification of the African tropical rain belt during MIS 5e, leading to a notable increase in the fresh water flux into the Red Sea. Such an increase significantly reduced the Red Sea salinity and exchange volume of the Red Sea with the Gulf of Aden. The Red Sea reacted to the MIS 5e insolation forcing by the expected increase in seasonal sea surface temperature amplitude and overall cooling caused by lower temperatures during deep water formation in winter.

  9. DOPPLER SIGNATURES OF THE ATMOSPHERIC CIRCULATION ON HOT JUPITERS

    Energy Technology Data Exchange (ETDEWEB)

    Showman, Adam P.; Lewis, Nikole K. [Department of Planetary Sciences and Lunar and Planetary Laboratory, The University of Arizona, 1629 University Boulevard, Tucson, AZ 85721 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Shabram, Megan, E-mail: showman@lpl.arizona.edu [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611-2055 (United States)

    2013-01-01

    The meteorology of hot Jupiters has been characterized primarily with thermal measurements, but recent observations suggest the possibility of directly detecting the winds by observing the Doppler shift of spectral lines seen during transit. Motivated by these observations, we show how Doppler measurements can place powerful constraints on the meteorology. We show that the atmospheric circulation-and Doppler signature-of hot Jupiters splits into two regimes. Under weak stellar insolation, the day-night thermal forcing generates fast zonal jet streams from the interaction of atmospheric waves with the mean flow. In this regime, air along the terminator (as seen during transit) flows toward Earth in some regions and away from Earth in others, leading to a Doppler signature exhibiting superposed blueshifted and redshifted components. Under intense stellar insolation, however, the strong thermal forcing damps these planetary-scale waves, inhibiting their ability to generate jets. Strong frictional drag likewise damps these waves and inhibits jet formation. As a result, this second regime exhibits a circulation dominated by high-altitude, day-to-night airflow, leading to a predominantly blueshifted Doppler signature during transit. We present state-of-the-art circulation models including non-gray radiative transfer to quantify this regime shift and the resulting Doppler signatures; these models suggest that cool planets like GJ 436b lie in the first regime, HD 189733b is transitional, while planets hotter than HD 209458b lie in the second regime. Moreover, we show how the amplitude of the Doppler shifts constrains the strength of frictional drag in the upper atmospheres of hot Jupiters. If due to winds, the {approx}2 km s{sup -1} blueshift inferred on HD 209458b may require drag time constants as short as 10{sup 4}-10{sup 6} s, possibly the result of Lorentz-force braking on this planet's hot dayside.

  10. Deep Circulation in the South China Sea

    Science.gov (United States)

    Zhao, Xiaolong; Zhao, Wei; Xu, Xiaobiao; Tian, Jiwei; Zhou, Chun

    2016-04-01

    The South China Sea (SCS) is the largest marginal sea of the northwest Pacific. The deep circulation in the SCS is investigated on the basis of the Hybrid Coordinate Ocean Model (HYCOM). All the experiments show reasonable agreement with observation from mooring arrays. Analysis of these results provides a detailed spatial structure and temporal variability of the deep circulation in the SCS. The major features of the SCS deep circulation are basin-scale cyclonic gyre and concentrated deep western boundary current (DWBC). The transport of the DWBC is ~2 Sv at 16.5°N with a width of ~53 km. As flowing southwestward, the DWBC becomes weaker with a wider range. Deep upwelling in the SCS is estimated of 0.19 to 1.15 m d-1 with the strongest area around the DWBC. The model results reveal the existence of 80 to 120 days oscillation in the deep northeastern circulation and the DWBC, which are also the areas with large eddy kinetic energy. This seasonal oscillation is northwestward with a velocity amplitude of ~1.0~1.5 cm s-1. The distribution of mixing parameters in the deep SCS plays a role in both spatial structure and volume transport of the deep circulation. Compared with the north shelf of the SCS with the Luzon Strait, deep circulation in the SCS is more sensitive to the large vertical mixing parameters of the Zhongsha Island Chain area.

  11. Surgical myocardial revascularization without extracorporeal circulation

    Directory of Open Access Journals (Sweden)

    Salomón Soriano Ordinola Rojas

    2003-05-01

    Full Text Available OBJECTIVE: To assess the immediate postoperative period of patients undergoing myocardial revascularization without extracorporeal circulation with different types of grafts. METHODS: One hundred and twelve patients, 89 (79.5% of whom were males, were revascularized without extracorporeal circulation. Their ages ranged from 39 to 85 years. The criteria for indicating myocardial revascularization without extracorporeal circulation were as follows: revascularized coronary artery caliber > 1.5 mm, lack of intramyocardial trajectory on coronary angiography, noncalcified coronary arteries, and tolerance of the heart to the different rotation maneuvers. RESULTS: Myocardial revascularization without extracorporeal circulation was performed in 112 patients. Three were converted to extracorporeal circulation, which required a longer hospital stay but did not impact mortality. During the procedure, the following events were observed: atrial fibrillation in 10 patients, ventricular fibrillation in 4, total transient atrioventricular block in 2, ventricular extrasystoles in 58, use of a device to retrieve red blood cells in 53, blood transfusion in 8, and arterial hypotension in 89 patients. Coronary angiography was performed in 20 patients on the seventh postoperative day when the grafts were patent. CONCLUSION: Myocardial revascularization without extracorporeal circulation is a reproducible technique that is an alternative for treating ischemic heart disease.

  12. Doppler Signatures of the Atmospheric Circulation on Hot Jupiters

    CERN Document Server

    Showman, Adam P; Lewis, Nikole K; Shabram, Megan

    2013-01-01

    The meteorology of hot Jupiters has been characterized primarily with thermal measurements, but recent observations suggest the possibility of directly detecting the winds by observing the Doppler shift of spectral lines seen during transit. Motivated by these observations, we show how Doppler measurements can place powerful constraints on the meteorology. We show that the atmospheric circulation--and Doppler signature--of hot Jupiters splits into two regimes. Under weak stellar insolation, the day-night thermal forcing generates fast zonal jet streams from the interaction of atmospheric waves with the mean flow. In this regime, air along the terminator (as seen during transit) flows toward Earth in some regions and away from Earth in others, leading to a Doppler signature exhibiting superposed blue- and redshifted components. Under intense stellar insolation, however, the strong thermal forcing damps these planetary-scale waves, inhibiting their ability to generate jets. Strong frictional drag likewise damps...

  13. Regulation of the pulmonary circulation in the fetus and newborn.

    Science.gov (United States)

    Gao, Yuansheng; Raj, J Usha

    2010-10-01

    During the development of the pulmonary vasculature in the fetus, many structural and functional changes occur to prepare the lung for the transition to air breathing. The development of the pulmonary circulation is genetically controlled by an array of mitogenic factors in a temporo-spatial order. With advancing gestation, pulmonary vessels acquire increased vasoreactivity. The fetal pulmonary vasculature is exposed to a low oxygen tension environment that promotes high intrinsic myogenic tone and high vasocontractility. At birth, a dramatic reduction in pulmonary arterial pressure and resistance occurs with an increase in oxygen tension and blood flow. The striking hemodynamic differences in the pulmonary circulation of the fetus and newborn are regulated by various factors and vasoactive agents. Among them, nitric oxide, endothelin-1, and prostaglandin I(2) are mainly derived from endothelial cells and exert their effects via cGMP, cAMP, and Rho kinase signaling pathways. Alterations in these signaling pathways may lead to vascular remodeling, high vasocontractility, and persistent pulmonary hypertension of the newborn.

  14. Circulation model for water circulation and purification in a water Cerenkov detector

    Institute of Scientific and Technical Information of China (English)

    LU Hao-Qi; YANG Chang-Gen; WANG Ling-Yu; XU Ji-Lei; WANG aui-Guang; WANG Zhi-Min; WANG Yi-Fang

    2009-01-01

    Owing to its low cost and good transparency, highly purified water is widely used as a medium in large water Cerenkov detector experiments. The water circulation and purification system is usually needed to keep the water in good quality. In this work, a practical circulation model is built to describe the variation of the water resistivity in the circulation process and compared with the data obtained from a prototype experiment. The successful test of the model makes it useful in the future design and optimization of the circulation/purification system.

  15. Detection and isolation of circulating melanoma cells using photoacoustic flowmetry.

    Science.gov (United States)

    O'Brien, Christine M; Rood, Kyle; Sengupta, Shramik; Gupta, Sagar K; DeSouza, Thiago; Cook, Aaron; Viator, John A

    2011-11-25

    Circulating tumor cells (CTCs) are those cells that have separated from a macroscopic tumor and spread through the blood and lymph systems to seed secondary tumors(1,2,3). CTCs are indicators of metastatic disease and their detection in blood samples may be used to diagnose cancer and monitor a patient's response to therapy. Since CTCs are rare, comprising about one tumor cell among billions of normal blood cells in advanced cancer patients, their detection and enumeration is a difficult task. We exploit the presence of pigment in most melanoma cells to generate photoacoustic, or laser induced ultrasonic waves in a custom flow cytometer for detection of circulating melanoma cells (CMCs)(4,5). This process entails separating a whole blood sample using centrifugation and obtaining the white blood cell layer. If present in whole blood, CMCs will separate with the white blood cells due to similar density. These cells are resuspended in phosphate buffered saline (PBS) and introduced into the flowmeter. Rather than a continuous flow of the blood cell suspension, we induced two phase flow in order to capture these cells for further study. In two phase flow, two immiscible liquids in a microfluidic system meet at a junction and form alternating slugs of liquid(6,7). PBS suspended white blood cells and air form microliter slugs that are sequentially irradiated with laser light. The addition of a surfactant to the liquid phase allows uniform slug formation and the user can create different sized slugs by altering the flow rates of the two phases. Slugs of air and slugs of PBS with white blood cells contain no light absorbers and hence, do not produce photoacoustic waves. However, slugs of white blood cells that contain even single CMCs absorb laser light and produce high frequency acoustic waves. These slugs that generate photoacoustic waves are sequestered and collected for cytochemical staining for verification of CMCs.

  16. A Global Ocean Biogeochemistry General Circulation Model and its Simulations

    Institute of Scientific and Technical Information of China (English)

    XU Yongfu; LI Yangchun; CHU Min

    2013-01-01

    An ocean biogeochemistry model was developed and incorporated into a global ocean general circulation model (LICOM) to form an ocean biogeochemistry general circulation model (OBGCM).The model was used to study the natural carbon cycle and the uptake and storage of anthropogenic CO2 in the ocean.A global export production of 12.5 Pg C yr-1 was obtained.The model estimated that in the pre-industrial era the global equatorial region within ±15° of the equator released 0.97 Pg C yr-1 to the atmosphere,which was balanced by the gain of CO2 in other regions.The post-industrial air-sea CO2 flux indicated the oceanic uptake of CO2 emitted by human activities.An increase of 20-50 μmol kg-1 for surface dissolved inorganic carbon (DIC) concentrations in the 1990s relative to pre-industrial times was obtained in the simulation,which was consistent with data-based estimates.The model generated a total anthropogenic carbon inventory of 105 Pg C as of 1994,which was within the range of estimates by other researchers.Various transports of both natural and anthropogenic DIC as well as labile dissolved organic carbon (LDOC)were estimated from the simulation.It was realized that the Southern Ocean and the high-latitude region of the North Pacific are important export regions where accumulative air-sea CO2 fluxes are larger than the DIC inventory,whereas the subtropical regions are acceptance regions.The interhemispheric transport of total natural carbon (DIC+LDOC) was found to be northward (0.11 Pg C yr-1),which was just balanced by the gain of carbon from the atmosphere in the Southern Hemisphere.

  17. Model prediction of the operating behavior of a circulating fluidized bed boiler

    Institute of Scientific and Technical Information of China (English)

    王勤辉; 骆仲泱; 倪明江; 岑可法

    2002-01-01

    An improved mathematical model for a circulating fluidized bed (CFB) boiler based on the model developed earlier by the authors was applied to simulate the operation of a 12 MW CFB boiler. The influences of the excess air ratio, primary air ratio, coal particle size distribution, coal properties (ash content and volatile content) and Ca/S ratio on the boiler operation were analyzed. The results showed that the model simulation may be applied to the optimum design and economic operation of the CFB boiler.

  18. Model prediction of the operating behavior of a circulating fluidized bed boiler

    Institute of Scientific and Technical Information of China (English)

    王勤辉; 骆仲泱; 倪明江; 岑可法

    2002-01-01

    An improved mathematical model for a circulating fluidized bed (CFB) boiler baaed on the model developed earlier by the authors was applied to simulate the operation of a 12 MW CFB boiler.The influences of the excess air ratio, primary air ratio, coal particle size distribution, coal properties (ash content and volatile content) and Ca/S ratio on the boiler operation were analyzed. The results showed that the model simulation may be applied to the optimum design and economic operation of the CFB boiler.

  19. Connection between ozone concentration and atmosphere circulation at peak Moussala

    Science.gov (United States)

    Nojarov, Peter; Ivanov, Peter; Kalapov, Ivo; Penev, Ilia; Drenska, Mirolujba

    2009-09-01

    Connection between ozone concentration and atmosphere circulation is investigated based on measurements at BEO station, peak Moussala (2,925 m a.s.l.), for the period 09 August 2006 to 29 January 2008. Ozone concentration data are collected with UV-analyzer “Environnement O3 42” and meteo data with weather station “Vaisala”. There are measurements of 7Be. Data from NOAA HYSPLIT model for particle trajectories are also used. Eight wind directions and three ranges of wind velocities are employed in the analysis. A comparison of ozone concentrations in upward and downward air transport according to HYSPLIT model is made. The number of cases with ozone concentration above 63 ppb has been counted. Mann-Whitney nonparametric test is employed as a basic statistical method. Correlation between atmosphere pressure and tropospheric ozone content is made. The same is done for 7Be and ozone. The main conclusion is that there is not any local or regional pollution effect detectable at peak Moussala, but most of the ozone measured is due to emissions of hydrocarbons and NO x over a larger region. There could be some regional sources of ozone building substances in southwest direction from peak Moussala. Air transported from the north quarter has higher ozone concentrations compared to the south quarter. In vertical direction, upward transport of air masses shows higher values of ozone concentration. Higher wind velocity is associated with low ozone concentrations at peak Moussala. The annual course of ozone concentration has summer maximum and winter minimum. There is right connection between air pressure and ozone concentration. The same is valid for the correlation between 7Be and ozone. Diurnal ozone course shows daytime maximum in winter and nighttime maximum in summer.

  20. Air surveillance

    Energy Technology Data Exchange (ETDEWEB)

    Patton, G.W.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the air surveillance and monitoring programs currently in operation at that Hanford Site. Atmospheric releases of pollutants from Hanford to the surrounding region are a potential source of human exposure. For that reason, both radioactive and nonradioactive materials in air are monitored at a number of locations. The influence of Hanford emissions on local radionuclide concentrations was evaluated by comparing concentrations measured at distant locations within the region to concentrations measured at the Site perimeter. This section discusses sample collection, analytical methods, and the results of the Hanford air surveillance program. A complete listing of all analytical results summarized in this section is reported separately by Bisping (1995).

  1. 46 CFR 56.50-45 - Circulating pumps.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Circulating pumps. 56.50-45 Section 56.50-45 Shipping... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-45 Circulating pumps. (a) A main circulating pump and emergency means for circulating water through the main condenser shall be provided....

  2. Coronary air embolism in off-pump surgery caused by blower-mister device.

    Science.gov (United States)

    Korkmaz, Askin Ali; Guden, Mustafa; Korkmaz, Feride; Yuce, Murat

    2008-01-01

    Gaseous emboli caused by the blower-mister result in air locks within coronary vessels. We describe the case of a coronary air embolism caused by a blower-mister device on off-pump surgery. The tip of the device unexpectedly entered the coronary artery through arteriotomy and caused the air emboli. Air locks in the coronary circulation led to hemodynamic deterioration, and cardiopulmonary bypass was started following the emergency cannulation.

  3. NAO-ocean circulation interactions in a coupled general circulation model

    Energy Technology Data Exchange (ETDEWEB)

    Bellucci, A. [Centro Euro-Mediterraneo per i Cambiamenti Climatici, Bologna (Italy); Gualdi, S.; Navarra, A. [Centro Euro-Mediterraneo per i Cambiamenti Climatici, Bologna (Italy); Istituto Nazionale di Geofisica e Vulcanologia, Bologna (Italy); Scoccimarro, E. [Istituto Nazionale di Geofisica e Vulcanologia, Bologna (Italy)

    2008-12-15

    The interplay between the North Atlantic Oscillation (NAO) and the large scale ocean circulation is inspected in a twentieth century simulation conducted with a state-of-the-art coupled general circulation model. Significant lead-lag covariance between oceanic and tropospheric variables suggests that the system supports a damped oscillatory mode involving an active ocean-atmosphere coupling, with a typical NAO-like space structure and a 5 years timescale, qualitatively consistent with a mid-latitude delayed oscillator paradigm. The two essential processes governing the oscillation are (1) a negative feedback between ocean gyre circulation and the high latitude SST meridional gradient and (2) a positive feedback between SST and the NAO. The atmospheric NAO pattern appears to have a weaker projection on the ocean meridional overturning, compared to the gyre circulation, which leads to a secondary role for the thermohaline circulation in driving the meridional heat transport, and thus the oscillatory mode. (orig.)

  4. Air pollution and cardiovascular disease.

    Science.gov (United States)

    Nogueira, J Braz

    2009-06-01

    Air pollution is associated with increased cardiovascular morbidity and mortality. Recent experimental and epidemiologic studies show that particulate matter (PM) air pollution with PM10 or inhalable (thoracic) particles (mean aerodynamic diameter particles (aerodynamic diameter biological mechanisms responsible for adverse cardiovascular outcomes associated with PM have been described, including the release of pro-oxidative and pro-inflammatory mediators from the lungs into the circulation, autonomic nervous system imbalance, and the direct actions on the heart and vasculature of ultrafine particles translocated into the systemic circulation. The induction of oxidative stress by these particles may be central to all of these putative pathways that trigger coagulation and thrombosis, increased heart rate and reduced heart rate variability, endothelial dysfunction, arterial vasoconstriction, apoptosis, and hypertension. In chronic exposures these alterations favor the development and progression of atherosclerosis and possibly of hypertension in the long term, and in the short term acute exposures contribute to plaque instability, affect various traditional risk factors and trigger acute cardiovascular events (myocardial ischemia and infarction, stroke, heart failure, arrhythmias, and sudden death), particularly in high-risk subjects. There are currently also significant concerns with the risks of engineered nanoparticles.

  5. Circulating Endothelial Microparticles in Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    A. F. Tramontano

    2010-01-01

    Full Text Available Background. Endothelial Microparticles (EMPs are small vesicles shed from activated or apoptotic endothelial cells and involved in cellular cross-talk. Whether EMP immunophenotypes vary according to stimulus in Diabetes Mellitus (DM is not known. We studied the cellular adhesion molecule (CAM profile of circulating EMPs in patients with and without Diabetes Mellitus type 2, who were undergoing elective cardiac catheterization. Methods and Results. EMPs were analyzed by flow cytometry. The absolute median number of EMPs (EMPs/L specific for CD31, CD105, and CD106 was significantly increased in the DM population. The ratio of CD62E/CD31 EMP populations reflected an apoptotic process. Conclusion. Circulating CD31+, CD105+, and CD106+ EMPs were significantly elevated in patients with DM. EMPs were the only independent predictors of DM in our study cohort. In addition, the EMP immunophenotype reflected an apoptotic process. Circulating EMPs may provide new options for risk assessment.

  6. Walker circulation in a transient climate

    Science.gov (United States)

    Plesca, Elina; Grützun, Verena; Buehler, Stefan A.

    2016-04-01

    The tropical overturning circulations modulate the heat exchange across the tropics and between the tropics and the poles. The anthropogenic influence on the climate system will affect these circulations, impacting the dynamics of the Earth system. In this work we focus on the Walker circulation. We investigate its temporal and spatial dynamical changes and their link to other climate features, such as surface and sea-surface temperature patterns, El-Niño Southern Oscillation (ENSO), and ocean heat-uptake, both at global and regional scale. In order to determine the impact of anthropogenic climate change on the tropical circulation, we analyze the outputs of 28 general circulation models (GCMs) from the CMIP5 project. We use the experiment with 1% year-1 increase in CO2 concentration from pre-industrial levels to quadrupling of the concentration. Consistent with previous studies (ex. Ma and Xie 2013), we find that for this experiment most GCMs associate a weakening Walker circulation to a warming transient climate. Due to the role of the Walker Pacific cell in the meridional heat and moisture transport across the tropical Pacific and also the connection to ENSO, we find that a weakened Walker circulation correlates with more extreme El-Niño events, although without a change in their frequency. The spatial analysis of the Pacific Walker cell suggests an eastward displacement of the ascending branch, which is consistent with positive SST anomalies over the tropical Pacific and the link of the Pacific Walker cell to ENSO. Recent studies (ex. England et al. 2014) have linked a strengthened Walker circulation to stronger ocean heat uptake, especially in the western Pacific. The inter-model comparison of the correlation between Walker circulation intensity and ocean heat uptake does not convey a robust response for the investigated experiment. However, there is some evidence that a stronger weakening of the Walker circulation is linked to a higher transient climate

  7. A 12 GHz broadband latching circulator

    Science.gov (United States)

    Katoh, Y.; Konishi, H.; Sakamoto, K.

    The two kinds of latching circulators, external return path and internal return path, are defined, noting the advantages (faster switching speed, lower switching energy, less complicated fabrication) offered by the internal configuration. It is noted, however, that this kind of circulator is difficult to make broadband because the return paths do not seem to act as part of the ferrite junction. The development of a 12-GHz broadband, internal return path circulator with impedance matching transformer and in-phase adjustment screws designed using eigenvalue measurement is described. In describing the operating characteristics, it is noted that more than 25 dB isolation over 11 GHz to 13.5 GHz and 0.25 dB insertion loss is obtained.

  8. Royal Danish Air Force. Air Operations Doctrine

    DEFF Research Database (Denmark)

    Nørby, Søren

    This brief examines the development of the first Danish Air Force Air Operations Doctrine, which was officially commissioned in October 1997 and remained in effect until 2010. The development of a Danish air power doctrine was heavily influenced by the work of Colonel John Warden (USAF), both...... through his book ”The Air Campaign” and his subsequent planning of the air campaign against Iraq in 1990-1991. Warden’s ideas came to Denmark and the Danish Air Force by way of Danish Air Force students attending the United States Air Force Air University in Alabama, USA. Back in Denmark, graduates from...... the Air University inspired a small number of passionate airmen, who then wrote the Danish Air Operations Doctrine. The process was supported by the Air Force Tactical Command, which found that the work dovetailed perfectly with the transformation process that the Danish Air Force was in the midst...

  9. Visible light optical coherence tomography for microvascular oximetry in ocular circulation (Conference Presentation)

    Science.gov (United States)

    Chen, Siyu; Yi, Ji; Zhang, Hao F.

    2016-03-01

    Visible light optical coherence tomography (vis-OCT) is intrinsically capable of optical determination of blood oxygen saturation (sO2). Thanks to its 3D sectioning ability, confounding factors that plaque multi-wavelength fundus photography can be avoided. We further supplemented it with motion-enhanced angiography (vis-OCTA), which allowed us to resolve retinal micro vessels without losing spectral information. As a result, spectroscopic vis-OCTA can extract microvascular sO2 which are generally inaccessible. Here we extend the theoretical formulation of vis-OCTA oximetry to include optical attenuation, scattering and motion contrast. The model allows robust estimation of sO2, while also promising reduction of illuminating power to 1/3 of current value of ~1 mW. To demonstrate the capability of our approach, we performed oxygen challenge while taking vis-OCTA measurements on rat ocular circulation in vivo. We supplied the experiment animal with the following gas mixture: normal air, 5% CO2 air, pure O2 and 10% O2 air. For each inhalation gas, the OCTA measurements were compared with peripheral capillary sO2 (spO2) provided by a pulse oximeter. The retinal artery sO2 measurements corresponded well with spO2 reading as expected (R2 = 0.87). We found that both retinal and choroidal circulation sO2 moderately increased when we supplied 5% CO2 air. 100% O2 inhalation significantly increased both artery and vein oxygenation. On the contrary, 10% O2 air could deplete the oxygen reservoir in the circulation and lead to low sO2 readings.

  10. Application of Circulation Controlled Blades for Vertical Axis Wind Turbines

    Directory of Open Access Journals (Sweden)

    Velissarios Kourkoulis

    2013-07-01

    Full Text Available The blades of a vertical axis wind turbine (VAWT rotor see an inconsistent angle of attack through its rotation. Consequently, VAWT blades generally use symmetrical aerofoils with a lower lift-to-drag ratio than cambered aerofoils tailored to maximise horizontal axis wind turbine rotor performance. This paper considers the feasibility of circulation controlled (CC VAWT blades, using a tangential air jet to provide lift and therefore power augmentation. However CC blade sections require a higher trailing-edge thickness than conventional sections giving rise to additional base drag. The choice of design parameters is a compromise between lift augmentation, additional base drag as well as the power required to pump the air jet. Although CC technology has been investigated for many years, particularly for aerospace applications, few researchers have considered VAWT applications. This paper considers the feasibility of the technology, using Computational Fluid Dynamics to evaluate a baseline CC aerofoil with different trailing-edge ellipse shapes. Lift and drag increments due to CC are considered within a momentum based turbine model to determine net power production. The study found that for modest momentum coefficients significant net power augmentation can be achieved with a relatively simple aerofoil geometry if blowing is controlled through the blades rotation.

  11. Experimental study of natural circulation circuit

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

    This work presents an experimental study about fluid flows behavior in natural circulation, under conditions of single-phase flow. The experiment was performed through experimental thermal-hydraulic circuit built at IEN. This test equipment has performance similar to passive system of residual heat removal present in Advanced Pressurized Water Reactors (APWR). This experimental study aims to observing and analyzing the natural circulation phenomenon, using this experimental circuit that was dimensioned and built based on concepts of similarity and scale. This philosophy allows the analysis of natural circulation behavior in single-phase flow conditions proportionally to the functioning real conditions of a nuclear reactor. The experiment was performed through procedures to initialization of hydraulic feeding of primary and secondary circuits and electrical energizing of resistors installed inside heater. Power controller has availability to adjust values of electrical power to feeding resistors, in order to portray several conditions of energy decay of nuclear reactor in a steady state. Data acquisition system allows the measurement and monitoring of the evolution of the temperature in various points through thermocouples installed in strategic points along hydraulic circuit. The behavior of the natural circulation phenomenon was monitored by graphical interface on computer screen, showing the temperature evolutions of measuring points and results stored in digital spreadsheets. The results stored in digital spreadsheets allowed the getting of data to graphic construction and discussion about natural circulation phenomenon. Finally, the calculus of Reynolds number allowed the establishment for a correlation of friction in function of geometric scales of length, heights and cross section of tubing, considering a natural circulation flow throughout in the region of hot leg. (author)

  12. The stripline circulator theory and practice

    CERN Document Server

    Helszajn, J

    2008-01-01

    Stripline circulator theory and applications from the world's foremost authority. The stripline junction circulator is a unique three-port non-reciprocal microwave junction used to connect a single antenna to both a transmitter and a receiver. Its operation relies on the interaction between an electron spin in a suitably magnetized insulator with an alternating radio frequency magnetic field. In its simplest form, it consists of a microwave planar gyromagnetic resonator symmetrically coupled by three transmission lines. This book explores the magnetic interaction involved in the stripline circ.

  13. Quenching phenomena in natural circulation loop

    Energy Technology Data Exchange (ETDEWEB)

    Umekawa, Hisashi; Ozawa, Mamoru [Kansai Univ., Osaka (Japan); Ishida, Naoki [Daihatsu Motor Company, Osaka (Japan)

    1995-09-01

    Quenching phenomena has been investigated experimentally using circulation loop of liquid nitrogen. During the quenching under natural circulation, the heat transfer mode changes from film boiling to nucleate boiling, and at the same time flux changes with time depending on the vapor generation rate and related two-phase flow characteristics. Moreover, density wave oscillations occur under a certain operating condition, which is closely related to the dynamic behavior of the cooling curve. The experimental results indicates that the occurrence of the density wave oscillation induces the deterioration of effective cooling of the heat surface in the film and the transition boiling regions, which results in the decrease in the quenching velocity.

  14. First circulating beam in the AA

    CERN Multimedia

    1980-01-01

    On 3 July 1980, two years after project authorization, beam circulated for the first time in the AA. It was a 3.56 GeV/c proton test beam. We see an expecting crowd, minutes before the happy event. The persons are too numerous to name them all, but the 3 most prominent ones are at the centre (left to right): Roy Billinge (Joint AA Project Leader, with his hand on the control box), Eifionydd Jones (white shirt), Simon van der Meer (spiritus rector and Joint AA Project Leader). The first antiprotons were injected, made to circulate and cooled soon after, on 14 July 1980.

  15. GSPEL - Air Filtration Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Evaluation capabilities for air filtration devices The Air Filtration Lab provides testing of air filtration devices to demonstrate and validate new or legacy system...

  16. Influence of external circulation on sludge characteristics during start-up of internal circulation reactor

    Institute of Scientific and Technical Information of China (English)

    DING Jian-nan; WANG Dian-zuo

    2005-01-01

    The start-up of external circulation-added internal circulation(IC) reactor was finished in 26 d, 32 d fewer than that of IC reactor. To evaluate the influence of the added external circulation on the development of granular sludge, the characteristics of the granular sludge taken from the two tested laboratory-scale reactors during start-up were studied. The results show that the added external circulation can enhance biomass granulation, accelerate granule development and improve sludge characteristics. At the end of start-up, the granular size of sludge in external circulation-added IC reactor greatly increases with a size distribution much better than that of sludge in IC reactor. The granular sludge originated from external circulation-added IC reactor contains more extracellular polymers and has a greater settling velocity than that from IC reactor. Methanogenic activity of the granular sludge from the external circulation-added IC reactor started 26 d ago reaches 358.23 mL·g-1·d-1, 1.66 and 1.20 times as great as that of the sludge from the IC reactor started 26 d and 58 d ago respectively.

  17. Circulation patterns governing October snowfalls in southern Siberia

    Science.gov (United States)

    Bednorz, Ewa; Wibig, Joanna

    2015-12-01

    This study is focused on early fall season in southern Siberia (50-60 N) and is purposed as a contribution to the discussion on the climatic relevance of October Eurasian snow cover. Analysis is based on the daily snow depth data from 43 stations from years 1980-2012, available in the database of All-Russian Research Institute of Hydrometeorological Information—World Data Centre. The snow cover season in southern Siberia starts in early autumn and the number of days with snowfall varies from less than 5 days in the southernmost zone along the parallel 50 N to more than 25 days in the northeastern part of the analyzed area. October snowfall in southern Siberia is associated with occurrence of negative anomalies of sea level pressure (SLP), usually spreading right over the place of recorded intense snowfall or extending eastward from it. Negative anomalies of air temperature at the 850 hPa geopotential level (T850) occurring with increased cyclonic activity are also observed. Negative T850 anomalies are located west or northwest of the SLP depressions. Counterclockwise circulation around low-pressure systems transports cold Arctic air from the north or even colder Siberian polar air from the east, to the west, and northwest parts of cyclones, and induces negative anomalies of temperature. The pattern of T850 anomalies during heavy snowfalls in the eastern part of the southern Siberia is shifted counterclockwise in regard to SLP anomalies: the strongest negative T850 anomalies are located west or northwest of the SLP depressions.

  18. Air-to-Air Missile Vector Scoring

    Science.gov (United States)

    2012-03-22

    64 4.6. Unscented Kalman Filter Performance in Air-to-Air Missile Scor - ing Application with Continuous Velocity Dynamics Model (Tar- get...Filter Performance in Air-to-Air Missile Scor - ing Application with Continuous Velocity Dynamics Model (Tar- get Aircraft Executing a Vertical Climb...Kalman Filter Performance in Air-to-Air Missile Scor - ing Application with Continuous Velocity Dynamics Model (Tar- get Aircraft Non-maneuvering

  19. Modeling of urban heat island and its impacts on thermal circulations in the Beijing-Tianjin-Hebei region, China

    Science.gov (United States)

    Li, Mengmeng; Wang, Tijian; Xie, Min; Zhuang, Bingliang; Li, Shu; Han, Yong; Cheng, Nianliang

    2016-08-01

    Through regulating the land-atmosphere energy balance, urbanization plays an important role in modifying local circulations and cross-border transport of air pollutants. The Beijing-Tianjin-Hebei (BTH) metropolitan area in northern China is frequently influenced by complex atmospheric thermal circulations due to its special topography and geographic position. In this study, the Weather Research and Forecasting (WRF) model combined with remote sensing is used to explore the urbanization impacts on local circulations in the BTH region. The urban heat island (UHI) effect generated around Beijing and Tianjin shows complex interactions with local thermal circulations. Due to the combined effects of UHI and topography, the UHI circulation around Beijing and valley breeze at the southern slopes of Yan Mountain are coupled together to reinforce each other. At the coastal cities, the increased land/sea temperature gradient considerably accelerates the sea breeze along Bohai Bay and moves the sea breeze front further inland to reach as far as Beijing. This study may lay a foundation for the better understanding of air pollutant dispersion on complex terrain.

  20. Unsteady flow about a circulation control airfoil

    Institute of Scientific and Technical Information of China (English)

    刘晶昌; 孙茂; 吴礼义

    1996-01-01

    The unsteady flow around a circulation control (CC) airfoil was investigated with Navier-Stokes method,which includes the flow around CC airfoil with pulsating jet,the flow around oscillating CC airfoil,and the flow around oscillating CC airfoil with pulsating jet.Dynamic properties of the flow and the aerodynamic forces were rewaled.

  1. IHI-FW circulating fluidized bed boiler

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, S.; Omata, K.; Ishimoto, R.; Asai, M. (Ishikawajima-Harima Heavy Industries, Co. Ltd., Tokyo (Japan))

    1993-07-01

    The technology and application of the circulating fluidized bed boiler (IHI-FW) are outlined. Circulating fluidized bed boilers have various features as compared with bubbling fluidized bed boilers as follows; a high combustion efficiency, efficient use of limestone for desulfurization, low NOx emission, adaptability to various fuels and capability to cope with load change. The IHI-FW boiler is furthermore featured by water-wall furnace of all-welded structure, water-cooled/steam cooled cyclone, and simple circulating system. The 30 t/h circulating fluidized bed boiler was introduced into the Tsu Works, Omikenshi Co., Ltd., Japan for private power generation. The boiler equipped with a backup heavy oil burner mainly uses semi-anthracite coal, and besides sulfur capture and NOx reduction functions of a bed, a bag filter with a high dust collecting efficiency is installed in an exhaust gas system. The installation period was reduced to 2.5 months, a half of conventional ones, by more assembly in a factory followed by less field works. 7 figs., 2 tabs.

  2. Redefining circulating tumor cells by image processing

    NARCIS (Netherlands)

    Ligthart, S.T.

    2012-01-01

    Circulating tumor cells (CTC) in the blood of patients with metastatic carcinomas are associated with poor survival and can be used to guide therapy. However, CTC are very heterogeneous in size and shape, and are present at very low frequencies. Missing or misjudging a few events may have great cons

  3. Frobenius circulant graphs of valency six

    CERN Document Server

    Thomson, Alison

    2012-01-01

    A Frobenius group is a permutation group which is transitive but not regular such that only the identity element can fix two points. It is well known that such a group is a semidirect product $G = K \\rtimes H$, where $K$ is a nilpotent normal subgroup. A first kind $G$-Frobenius graph is a Cayley graph on $K$ whose connection set is an $H$-orbit $a^H$ for some $a \\in K$ with $ = K$, where $H$ is of even order or $a$ is an involution. Such graphs admit 'perfect' routing and gossiping schemes in some sense. Because of this and the importance of circulant graphs in network design, it is desirable to classify first kind Frobenius circulant graphs. In this paper we classify all 6-valent first kind Frobenius circulant graphs. We give optimal gossiping, routing and broadcasting schemes for such graphs and compute their forwarding indices, Wiener indices and minimum gossip time. We also prove that the broadcasting time of any 6-valent first kind Frobenius circulant is equal to its diameter plus two or three, indicati...

  4. Detecting holocene changes in thermohaline circulation.

    Science.gov (United States)

    Keigwin, L D; Boyle, E A

    2000-02-15

    Throughout the last glacial cycle, reorganizations of deep ocean water masses were coincident with rapid millennial-scale changes in climate. Climate changes have been less severe during the present interglacial, but evidence for concurrent deep ocean circulation change is ambiguous.

  5. Detecting Holocene changes in thermohaline circulation

    OpenAIRE

    Keigwin, L. D.; Boyle, E.A.

    2000-01-01

    Throughout the last glacial cycle, reorganizations of deep ocean water masses were coincident with rapid millennial-scale changes in climate. Climate changes have been less severe during the present interglacial, but evidence for concurrent deep ocean circulation change is ambiguous.

  6. [Circulating "tumor markers" in gastrointestinal tumors].

    Science.gov (United States)

    Borlinghaus, P; Lamerz, R

    1991-09-01

    Tumor markers (TM) of the neoplastic cell can be divided into non-shedded substances and antigens shedded in blood, urine or other body fluids. For clinicians circulating TM are more important. All relevant circulating TM are not useful in screening of asymptomatic patients because of insufficient sensitivity and specificity. With caution they are useful in the observation of risk groups. Circulating TM have their main significance as additional parameters in monitoring symptomatic patients with malignancies. Several follow up determinations are more important than one single measurement. During follow up of tumor patients TM should not be checked automatically if there are no diagnostic or therapeutical consequences. The clinically most important circulating TM in non-hormone secreting tumors of the gastrointestinal tract are the oncofetal antigens CEA and AFP and antigens defined by monoclonal antibodies e. g. CA 19-9 and CA 72-4. AFP is the primary TM in hepatocellular carcinoma, often elevated in hepatoblastoma and always normal in cholangiocellular carcinoma. CEA is the TM of first choice in patients with colorectal carcinomas and liver metastasis. CA 19-9 is TM of first choice in pancreatic carcinoma and additionally of diagnostic value in cholangiocellular carcinoma and tumors of the bile ducts. In cancer of the stomach CA 19-9 and CEA are secondary TM in combination with CA 72-4 as primary TM. Care should be taken that slight and moderate elevations of TM can be observed in benign diseases of liver, pancreas and bowel.

  7. Identifying a Sea Breeze Circulation Pattern Over the Los Angeles Basin Using Airborne In Situ Carbon Dioxide Measurements

    Science.gov (United States)

    Brannan, A. L.; Schill, S.; Trousdell, J.; Heath, N.; Lefer, B. L.; Yang, M. M.; Bertram, T. H.

    2014-12-01

    The Los Angeles Basin in Southern California is an optimal location for a circulation study, due to its location between the Pacific Ocean to the west and the Santa Monica and San Gabriel mountain ranges to the east, as well as its booming metropolitan population. Sea breeze circulation carries air at low altitudes from coastal to inland regions, where the air rises and expands before returning back towards the coast at higher altitudes. As a result, relatively clean air is expected at low altitudes over coastal regions, but following the path of sea breeze circulation should increase the amount of anthropogenic influence. During the 2014 NASA Student Airborne Research Program, a highly modified DC-8 aircraft completed flights from June 23 to 25 in and around the LA Basin, including missed approaches at four local airports—Los Alamitos and Long Beach (coastal), Ontario and Riverside (inland). Because carbon dioxide (CO2) is chemically inert and well-suited as a conserved atmospheric tracer, the NASA Langley Atmospheric Vertical Observations of CO2 in the Earth's Troposphere (AVOCET) instrument was used to make airborne in situ carbon dioxide measurements. Combining measured wind speed and direction data from the aircraft with CO2 data shows that carbon dioxide can be used to trace the sea breeze circulation pattern of the Los Angeles basin.

  8. R9 Air Districts

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Region 9 Air Districts layer is a compilation of polygons representing the California Air Pollution Control and Air Quality Management Districts, Arizona Air...

  9. AirData

    Data.gov (United States)

    U.S. Environmental Protection Agency — The AirData site provides access to yearly summaries of United States air pollution data, taken from EPA's air pollution databases. AirData has information about...

  10. California Air Basins

    Data.gov (United States)

    California Department of Resources — Air ResourcesCalifornia Air Resources BoardThe following datasets are from the California Air Resources Board: * arb_california_airbasins - California Air BasinsThe...

  11. Development Strategies for Rural Key Circulation Service Network

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    The rural key circulation service network is an important channel for ensuring agricultural products’entry to market and urban industrial products’entry to rural areas.Through in-depth survey and research,we took a look at development changes and current situations of three circulation service networks,namely,circulation of nondurable consumer goods,circulation of agricultural means of production,and circulation of agricultural products.Based on several key problems in rural circulation service network,such as logistics problem,delivery problem,backward transaction mode,and the last kilometer information,we put forward corresponding development countermeasures.

  12. Radiosonde observational evidence of the influence of extreme SST gradient upon atmospheric meso-scale circulation

    Science.gov (United States)

    Nishikawa, H.; Tachibana, Y.; Udagawa, Y.

    2012-12-01

    Although the influence of the anomalous midlatitude SST upon atmospheric local circulation has been getting common in particular over the Kuroshio and the Gulf Stream regions, observational studies on the influence of the Okhotsk Sea, which is to the north of the Kuroshio, upon the atmospheric local circulation is much less than those of the Kuroshio. The climate of the Okhotsk SST is very peculiar. Extremely cold SST spots, whose summertime SST is lower than 5 Celsius degrees, are formed around Kuril Islands. Because SSTs are generally determined by local air-sea interaction as well as temperature advection, it is very difficult to isolate only the oceanic influence upon the atmosphere. The SST in this cold spot is, however, dominated by the tidal mixing, which is independent of the atmospheric processes. This unique condition may ease the account for the oceanic influence only. Although the SST environment of the Okhotsk Sea is good for understanding the oceanic influence upon the atmosphere, only a few studies has been executed in this region because of the difficulty of observations by research vessels in this region, where territory problems between Japan and Russia is unsolved. Because of the scant of direct observation, the Okhotsk Sea was still mysterious. In 2006 August, GPS radiosonde observation was carried out by Russian research vessel Khromov in the Sea of Okhotsk by the cooperation between Japan and Russia, and strong SST gradient of about 7 Celsius degrees/10km was observed around the Kuril Islands. The purpose of this study is to demonstrate observational finding of meso-scale atmospheric anticyclonic circulation influenced by the cold oceanic spot around the Kuril Island. The summaries of the observation are as follows. Meso-scale atmospheric ageostrophic anticyclonic circulation in the atmospheric marine-boundary layer is observed in and around the cold spot. A high air pressure area as compared with other surrounding areas is also located at the

  13. Blood Volume, Plasma Volume and Circulation Time in a High-Energy-Demand Teleost, the Yellowfin Tuna (Thunnus Albacares)

    DEFF Research Database (Denmark)

    Brill, R.W.; Cousins, K.L.; Jones, D.R.

    1998-01-01

    tuna, circulation time is approximately 0.4 min (47 ml kg-1/115 ml min-1 kg- 1) compared with 1.3 min (46 ml kg-1/35 ml min-1 kg-1) in yellowtail (Seriola quinqueradiata) and 1.9 min (35 ml kg-1/18 ml min-1 kg-1) in rainbow trout (Oncorhynchus mykiss). In air-breathing vertebrates, high metabolic rates...... are necessarily correlated with short circulation times. Our data are the first to imply that a similar relationship occurs in fishes....

  14. Summer atmospheric circulation anomalies over the Arctic Ocean and their influences on September sea ice extent: A cautionary tale

    Science.gov (United States)

    Serreze, Mark C.; Stroeve, Julienne; Barrett, Andrew P.; Boisvert, Linette N.

    2016-10-01

    Numerous studies have addressed links between summer atmospheric circulation patterns and interannual variability and the downward trend in total September Arctic sea ice extent. In general, low extent is favored when the preceding summer is characterized by positive sea level pressure (SLP) anomalies over the central Arctic Ocean north of Alaska. High extent is favored when low pressure dominates. If such atmospheric patterns could be predicted several months out, these links provide an avenue for improved seasonal predictability of total September extent. We analyze detrended September extent time series (1979-2015), atmospheric reanalysis fields, ice age and motion, and Atmospheric Infrared Sounder data, to show that while there is merit to this summer circulation framework, it has limitations. Large departures in total September extent relative to the trend line are preceded by a wide range of summer circulation patterns. While patterns for the four years with the largest positive departures in September extent have below average SLP over the central Arctic Ocean, they differ markedly in the magnitude and location of pressure and air temperature anomalies. Differences in circulation for the four years with the largest negative departures are equally prominent. Circulation anomalies preceding Septembers with ice extent close to the trend also have a wide range of patterns. In turn, years (such as 2013 and 2014) with almost identical total September extent were preceded by very different summer circulation patterns. September ice conditions can also be strongly shaped by events as far back as the previous winter or spring.

  15. EXTRACORPOREAL CIRCULATION: EFFECT OF LONG-TERM (24-HOUR) CIRCULATION ON BLOOD COMPONENTS

    OpenAIRE

    Solberg, Robert Glen

    2010-01-01

    Extracorporeal circulation damages blood and causes harmful side effects such as stroke and/or systemic inflammatory response in patients. Reactions of blood components to extracorporeal circulation include complement and inflammatory reactions, coagulation and thrombogenesis, frank hemolysis, and platelet activation and adhesion to the extracorporeal circuit. Non-physiologic pressure and flow produced by blood pumps contribute to blood injury. Two pump types, roller and centrifugal, are u...

  16. Air Warfare

    Science.gov (United States)

    2002-03-01

    undoubtedly begat the shield; poisonous gases were countered by the mask. Surely men on the surface of the earth will not have to submit to violent air attack...properties, production methods and cost of helium are given in “Balloon and Airship Gases ,” a volume of the Ronald Aeronautic Library. 5 More complete...becomes and more inse - cure. We shall see later that even some of the men who were advancing in the path prescribed by the principle of mass

  17. Ross ice shelf cavity circulation, residence time, and melting: Results from a model of oceanic chlorofluorocarbons

    Science.gov (United States)

    Reddy, Tasha E.; Holland, David M.; Arrigo, Kevin R.

    2010-04-01

    Despite their harmful effects in the upper atmosphere, anthropogenic chlorofluorocarbons dissolved in seawater are extremely useful for studying ocean circulation and ventilation, particularly in remote locations. Because they behave as a passive tracer in seawater, and their atmospheric concentrations are well-mixed, well-known, and have changed over time, they are ideal for gaining insight into the oceanographic characteristics of the isolated cavities found under Antarctic ice shelves, where direct observations are difficult to obtain. Here we present results from a modeling study of air-sea chlorofluorocarbon exchange and ocean circulation in the Ross Sea, Antarctica. We compare our model estimates of oceanic CFC-12 concentrations along an ice shelf edge transect to field data collected during three cruises spanning 16 yr. Our model produces chlorofluorocarbon concentrations that are quite similar to those measured in the field, both in magnitude and distribution, showing high values near the surface, decreasing with depth, and increasing over time. After validating modeled circulation and air-sea gas exchange through comparison of modeled temperature, salinity, and chlorofluorocarbons with field data, we estimate that the residence time of water in the Ross Ice Shelf cavity is approximately 2.2 yr and that basal melt rates for the ice shelf average 10 cm yr -1. The model predicts a seasonal signature to basal melting, with highest melt rates in the spring and also the fall.

  18. DEVELOPMENT OF PRESSURIZED CIRCULATING FLUIDIZED BED PARTIAL GASIFICATION MODULE (PGM)

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2002-03-29

    Foster Wheeler Development Corporation is working under DOE contract No. DE-FC26-00NT40972 to develop a partial gasification module (PGM) that represents a critical element of several potential coal-fired Vision 21 plants. When utilized for electrical power generation, these plants will operate with efficiencies greater than 60% while producing near zero emissions of traditional stack gas pollutants. The new process partially gasifies coal at elevated pressure producing a coal-derived syngas and a char residue. The syngas can be used to fuel the most advanced power producing equipment such as solid oxide fuel cells or gas turbines or processed to produce clean liquid fuels or chemicals for industrial users. The char residue is not wasted; it can also be used to generate electricity by fueling boilers that drive the most advanced ultra-supercritical pressure steam turbines. The unique aspect of the process is that it utilizes a pressurized circulating fluidized bed partial gasifier and does not attempt to consume the coal in a single step. To convert all the coal to syngas in a single step requires extremely high temperatures ({approx}2500 to 2800 F) that melt and vaporize the coal and essentially drive all coal ash contaminants into the syngas. Since these contaminants can be corrosive to power generating equipment, the syngas must be cooled to near room temperature to enable a series of chemical processes to clean the syngas. Foster Wheeler's process operates at much lower temperatures that control/minimize the release of contaminants; this eliminates/minimizes the need for the expensive, complicated syngas heat exchangers and chemical cleanup systems typical of high temperature gasification. By performing the gasification in a circulating bed, a significant amount of syngas can still be produced despite the reduced temperature and the circulating bed allows easy scale up to large size plants. Rather than air, it can also operate with oxygen to facilitate

  19. Warm World Ocean Thermohaline Circulation Model

    Science.gov (United States)

    Zimov, N.; Zimov, S. A.

    2014-12-01

    Modern day ocean circulation is dominated by thermal convection with cold waters subsiding in the Northern Atlantic, filling the ocean interior with cold and heavy water. However, ocean circulation diminished during the last glaciation and consequently the downwelling of the cold. Therefore interior ocean water temperatures must have been affected by other mechanisms which are negligible in the current state. We propose that the submergence of highly saline water from warm seas with high rates of evaporation (like the Red or Mediterranean Sea) was a major factor controlling ocean circulation during the last glaciation. Even today, waters in these poorly connected seas are the heaviest waters in the World ocean (1.029 g/cm3). The second mechanism affecting ocean temperature is the geothermal heat flux. With no heat exchange between the atmosphere and the ocean, geothermal heat flux through the ocean floor is capable of increasing ocean temperature by tens of degrees C over a 100 thousand year glacial cycle. To support these hypotheses we present an ocean box model that describes thermohaline circulation in the World Ocean. According to the model parameters, all water circulation is driven by the water density gradient. Boxes include high-latitude seas, high salinity seas, surface ocean, glaciers, and rift and lateral zones of the ocean interior. External heat sources are radiative forcing, affected by Milankovich cycles, and geothermal heat flux. Additionally this model accounts for the heat produced by organic rain decay. Taking all input parameters close to currently observed values, the model manages to recreate the glacial-interglacial cycles. During the glacial periods only haline circulation takes place, the ocean is strongly stratified, and the interior ocean accumulates heat while high-latitudes accumulate ice. 112,000 years after glaciation starts, water density on the ocean bottom becomes equal to the density of water in high-latitude seas, strong thermal

  20. Silent Circulation of Ross River Virus in French Polynesia

    Directory of Open Access Journals (Sweden)

    Maite Aubry

    2015-08-01

    Discussion: Our results support the existence of autochthonous RRV transmission and suggest that this pathogen has silently circulated in French Polynesia. These findings raise the question of possible undetected circulation of RRV in other Pacific Island Countries and Territories.

  1. Investigation of a hybrid PVT air collector system

    Science.gov (United States)

    Haddad, S.; Touafek, K.; Mordjaoui, M.; Khelifa, A.; Tabet, I.

    2017-02-01

    The photovoltaic thermal hybrid (PVT) collectors, which simultaneously produce electricity and heat, are an alternative to photovoltaic modules and thermal collectors installed separately. Indeed, the heat extracted from the solar cell is used to heat water or air, thereby cooling the cell, and thus increasing its energy efficiency. This paper deals with a hybrid PVT air collector in which a new design has been proposed and tested. Its principle is based on the return of the preheating air to a second heating. The air thus passes twice under the solar cells before being evacuated to the outside of the collector (for space heating). The system is modular and expandable to cover large spaces to be heated. The experimental results of this novel design are presented and discussed under both normal and forced circulation. This technique of air return shows favorable results in terms of the quality of the heated air and electric power generation.

  2. Genetically Encoded Voltage Indicators in Circulation Research.

    Science.gov (United States)

    Kaestner, Lars; Tian, Qinghai; Kaiser, Elisabeth; Xian, Wenying; Müller, Andreas; Oberhofer, Martin; Ruppenthal, Sandra; Sinnecker, Daniel; Tsutsui, Hidekazu; Miyawaki, Atsushi; Moretti, Alessandra; Lipp, Peter

    2015-09-08

    Membrane potentials display the cellular status of non-excitable cells and mediate communication between excitable cells via action potentials. The use of genetically encoded biosensors employing fluorescent proteins allows a non-invasive biocompatible way to read out the membrane potential in cardiac myocytes and other cells of the circulation system. Although the approaches to design such biosensors date back to the time when the first fluorescent-protein based Förster Resonance Energy Transfer (FRET) sensors were constructed, it took 15 years before reliable sensors became readily available. Here, we review different developments of genetically encoded membrane potential sensors. Furthermore, it is shown how such sensors can be used in pharmacological screening applications as well as in circulation related basic biomedical research. Potentials and limitations will be discussed and perspectives of possible future developments will be provided.

  3. On-Chip Microwave Quantum Hall Circulator

    Science.gov (United States)

    Mahoney, A. C.; Colless, J. I.; Pauka, S. J.; Hornibrook, J. M.; Watson, J. D.; Gardner, G. C.; Manfra, M. J.; Doherty, A. C.; Reilly, D. J.

    2017-01-01

    Circulators are nonreciprocal circuit elements that are integral to technologies including radar systems, microwave communication transceivers, and the readout of quantum information devices. Their nonreciprocity arises from the interference of microwaves over the centimeter scale of the signal wavelength, in the presence of bulky magnetic media that breaks time-reversal symmetry. Here, we realize a completely passive on-chip microwave circulator with size 1 /1000 th the wavelength by exploiting the chiral, "slow-light" response of a two-dimensional electron gas in the quantum Hall regime. For an integrated GaAs device with 330 μ m diameter and about 1-GHz center frequency, a nonreciprocity of 25 dB is observed over a 50-MHz bandwidth. Furthermore, the nonreciprocity can be dynamically tuned by varying the voltage at the port, an aspect that may enable reconfigurable passive routing of microwave signals on chip.

  4. Posterior circulation revascularization to manage vertebrobasilar occlusion

    Directory of Open Access Journals (Sweden)

    SHANG Yan-guo

    2012-06-01

    Full Text Available Objective To discuss the technique and effect of posterior circulation revascularization to manage vertebrobasilar occlusion. Methods Nine patients with vertebrobasilar occlusion were treated by using occipital artery-posterior inferior cerebellar artery bypass, superficial temporal artery-superior cerebellar artery bypass, superficial temporal artery-posterior cerebral artery bypass and occipital artery-vertebral artery bypass with radial artery graft. Results Intraoperative indocyanine green angiography showed all the bypass arteries were patent. Postoperative DSA or CTA showed bypass arteries patent in 8 patients, among whom seven patients got obvious improvement on MR or CT perfusion. One patient died of heart failure on the 15th day postoperative. During the follow-up of eight patients, no stroke reoccurred, four patients got back to nearly normal life. Conclusion Most of the patients with vertebrobasilar occlusion could benefit from the posterior circulation revascularization, which should be confirmed by randomized controlled clinical trials in the future.

  5. Congenital cardiovascular malformations and the fetal circulation.

    Science.gov (United States)

    Rudolph, A M

    2010-03-01

    After birth, gas exchange is achieved in the lung, whereas prenatally it occurs in the placenta. This is associated with differences in blood flow patterns in the fetus as compared with the postnatal circulation. Congenital cardiovascular malformations are associated with haemodynamic changes in the fetus, which differ from those occurring postnatally. Obstruction to cardiac outflow may alter myocardial development, resulting in progressive ventricular hypoplasia. Alteration of oxygen content may profoundly influence pulmonary vascular and ductus arteriosus responses. Interference in blood flow and oxygen content may affect cerebral development as a result of inadequate oxygen or energy substrate supply. The circulatory effects may be gestational dependent, related to maturation of vascular responses in different organs. These prenatal influences of congenital cardiac defects may severely affect immediate, as well as longterm, postnatal prognosis and survival. This has stimulated the development of techniques for palliation of disturbed circulation during fetal life.

  6. DEVELOPMENT OF WATER CIRCULATION MODEL INCLUDING IRRIGATION

    Science.gov (United States)

    Kotsuki, Shunji; Tanaka, Kenji; Kojiri, Toshiharu; Hamaguchi, Toshio

    It is well known that since agricultural water withdrawal has much affect on water circulation system, accurate analysis of river discharge or water balance are difficult with less regard for it. In this study, water circulation model composed of land surface model and distributed runoff model is proposed at 10km 10km resolution. In this model, irrigation water, which is estimated with land surface model, is introduced to river discharge analysis. The model is applied to the Chao Phraya River in Thailand, and reproduced seasonal water balance. Additionally, the discharge on dry season simulated with the model is improved as a result of including irrigation. Since the model, which is basically developed from global data sets, simulated seasonal change of river discharge, it can be suggested that our model has university to other river basins.

  7. Formation and plasma circulation of solar prominences

    CERN Document Server

    Xia, Chun

    2016-01-01

    Solar prominences are long-lived cool and dense plasma curtains in the hot and rarefied outer solar atmosphere or corona. The physical mechanism responsible for their formation and especially for their internal plasma circulation has been uncertain for decades. The observed ubiquitous down flows in quiescent prominences are difficult to interpret as plasma with high conductivity seems to move across horizontal magnetic field lines. Here we present three-dimensional numerical simulations of prominence formation and evolution in an elongated magnetic flux rope as a result of in-situ plasma condensations fueled by continuous plasma evaporation from the solar chromosphere. The prominence is born and maintained in a fragmented, highly dynamic state with continuous reappearance of multiple blobs and thread structures that move mainly downward dragging along mass-loaded field lines. The prominence plasma circulation is characterized by the dynamic balance between the drainage of prominence plasma back to the chromos...

  8. [William Harvey, discoverer of the blood circulation].

    Science.gov (United States)

    v Mühlendahl, K E

    2007-06-01

    William Harvey (1578-1657), living at the turn to modern times, scientifically speaking, was an eminent physician and scientist. He developed the concept of the circulation of the blood and his findings have proved to be correct in nearly all details to this day. He published his physiological findings and interpretations in a small, albeit epoch-making, volume: Exercitatio anatomica de motu cordis et sanguinis in animalibus, published in Frankfurt in 1628. On the occasion of the 350th anniversary of his death on June 3, 2007, this essay commemorates the work of this important physician, illustrating his brilliant conception of the blood circulation by quoting passages from De motu cordis et sanguinis.

  9. First circulating beam in the AA

    CERN Multimedia

    1980-01-01

    On 3 July 1980, two years after project authorization, beam circulated for the first time in the AA. It was a 3.5 GeV/c proton test beam. We see an expecting crowd, minutes before the happy event. The persons are to numerous to name them all. Heribert Koziol, apparently asleep, is answering the call from an impatient director. See also 8007094.

  10. Cluster Dynamics in a Circulating Fluidized Bed

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, C.P.; Breault, R.W.

    2006-11-01

    A common hydrodynamic feature in industrial scale circulating fluidized beds is the presence of clusters. The continuous formation and destruction of clusters strongly influences particle hold-up, pressure drop, heat transfer at the wall, and mixing. In this paper fiber optic data is analyzed using discrete wavelet analysis to characterize the dynamic behavior of clusters. Five radial positions at three different axial locations under five different operating were analyzed using discrete wavelets. Results are summarized with respect to cluster size and frequency.

  11. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    1992-02-01

    The objective of this DOE Cooperative Agreement is to conduct a cost-shared clean coal technology project to demonstrate the feasibility of circulating fluidized bed combustion technology and to evaluate economic, environmental, and operational benefits of CFB steam generators on a utility scale. At the conclusion of the Phase 2 program, testing related to satisfying these objectives was completed. Data analysis and reporting are scheduled for completion by October 1991. (VC)

  12. FORMATION AND PLASMA CIRCULATION OF SOLAR PROMINENCES

    OpenAIRE

    Xia, Chun; Keppens, Rony

    2016-01-01

    Solar prominences are long-lived cool and dense plasma curtains in the hot and rarefied outer solar atmosphere or corona. The physical mechanism responsible for their formation and especially for their internal plasma circulation has been uncertain for decades. The observed ubiquitous down flows in quiescent prominences are difficult to interpret as plasma with high conductivity seems to move across horizontal magnetic field lines. Here we present three-dimensional numerical simulations of pr...

  13. On circulant states with positive partial transpose

    OpenAIRE

    Chruściński, Dariusz; Kossakowski, Andrzej

    2007-01-01

    We construct a large class of quantum "d x d" states which are positive under partial transposition (so called PPT states). The construction is based on certain direct sum decomposition of the total Hilbert space displaying characteristic circular structure - that is way we call them circulant states. It turns out that partial transposition maps any such decomposition into another one and hence both original density matrix and its partially transposed partner share similar cyclic properties. ...

  14. Parallel Computing of Ocean General Circulation Model

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper discusses the parallel computing of the thirdgeneration Ocea n General Circulation Model (OGCM) from the State Key Laboratory of Numerical Mo deling for Atmospheric Science and Geophysical Fluid Dynamics(LASG),Institute of Atmosphere Physics(IAP). Meanwhile, several optimization strategies for paralle l computing of OGCM (POGCM) on Scalable Shared Memory Multiprocessor (S2MP) are presented. Using Message Passing Interface (MPI), we obtain super linear speedup on SGI Origin 2000 for parallel OGCM(POGCM) after optimization.

  15. The creation and circulation of public geographies

    OpenAIRE

    Kitchin, Rob; Linehan, Denis; O'Callaghan, Cian; Lawton, Philip

    2013-01-01

    In response to the commentaries, we discuss further how social media disrupts and remakes the creation and circulation of geographical knowledges and potentially reconfigures the moral economy of the social sciences. In particular, we examine questions of what is meant by public geography, the publics which such geographies serve, alternative and complementary approaches to social media, the politics of authorship within collective blogs, the politics and mechanisms of knowledge c...

  16. Circulating fluidized bed boilers design and operations

    CERN Document Server

    Basu, Prabir

    1991-01-01

    This book provides practicing engineers and students with insight into the design and operation of circulating fluidized bed (CFB) boilers. Through a combination of theoretical concepts and practical experience, this book gives the reader a basic understanding of the many aspects of this subject.Important environmental considerations, including solid waste disposal and predicted emissions, are addressed individually in separate chapters. This book places an emphasis on combustion, hydrodynamics, heat transfer, and material issues, and illustrates these concepts with numerous examples of pres

  17. The influence of atmospheric circulation on the intensity of urban heat island and urban cold island in Poznań, Poland

    Science.gov (United States)

    Półrolniczak, Marek; Kolendowicz, Leszek; Majkowska, Agnieszka; Czernecki, Bartosz

    2017-02-01

    The study has analyzed influence of an atmospheric circulation on urban heat island (UHI) and urban cold island (UCI) in Poznań. Analysis was conducted on the basis of temperature data from two measurement points situated in the city center and in the Ławica airport (reference station) and the data concerning the air circulation (Niedźwiedź's calendar of circulation types and reanalysis of National Centers for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR)). The cases with UHI constitute about 85 % of all data, and UCI phenomena appear with a frequency of 14 % a year. The intensity of UHI phenomenon is higher in the anticyclonic circulation types. During the year in anticyclonic circulation, intensity of UHI is 1.2 °C on average while in cyclonic is only 0.8 °C. The occurring of UHI phenomena is possible throughout all seasons of the year in all hours of the day usually in anticyclonic circulation types. The cases with highest UHI intensity are related mostly to nighttime. The cases of UCI phenomena occurred almost ever on the daytime and the most frequently in colder part of the year together with cyclonic circulation. Study based on reanalysis data indicates that days with large intensity of UHI (above 4, 5, and 6 °C) are related to anticyclonic circulation. Anticyclonic circulation is also promoting the formation of the strongest UCI. Results based on both reanalysis and the atmospheric circulation data (Niedźwiedź's circulation type) confirm that cases with the strongest UHI and UCI during the same day occur in strong high-pressure system with the center situated above Poland or central Europe.

  18. Air acupuncture therapy combined with manipulation on 90 cases of acute sprain and bruising of ankle joint%气针加手法治疗急性踝关节扭挫伤90例

    Institute of Scientific and Technical Information of China (English)

    王永红; 李斌

    2003-01-01

    @@ BACKGROUND: Air acupuncture therapy is to make use of time and space stimuli of air in acupoint and promote blood circulation to remove blood stasis, relieve swelling and pain through interstitial osmosis and absorption. Manipulation to acute sprain and bruising of ankle joint can achieve anatomic reduction as soon as possible, clear incarceration of synovium, promote circulation of qi and relieve pain and increase blood circulation of affected tissue.

  19. Pulmonary Air Embolism: An Infrequent Complication in the Radiology Suite

    Science.gov (United States)

    Lanfranco, Julio; Romero-Legro, Ivan; Freire, Amado X.; Nearing, Katherine; Ratnakant, Sanjay

    2017-01-01

    Patient: Female, 64 Final Diagnosis: Pulmonary air embolism Symptoms: Shortness of breath Medication: — Clinical Procedure: — Specialty: Critical Care Medicine Objective: Unusual or unexpected effect of treatment Background: Air embolism can occur in a number of medical-surgical situations. Venous air embolism is frequently lethal when a substantial amount enters the venous circulation rapidly and can lead to significant morbidity if crossover to the systemic arterial circulation occurs. The diagnosis of massive air embolism is usually made on clinical grounds by the development of abrupt hemodynamic compromise. The true incidence, morbidity, and mortality of this event is unknown given the difficulties in diagnosis. Case Report: An inadvertent antecubital venous injection of 150 mL of air using a contrast power injector during a computed tomography (CT) is reported. Immediate imaging (CT) showed a significant amount of air in the right atrium and right ventricular cavity, and air mixed with contrast in the main pulmonary artery and proximal divisions of the pulmonary circulation. Patient condition deteriorated requiring mechanical ventilation for 48 hours. Condition improved over the next few days and patient was successfully extubated and discharged home. Conclusions: Air embolism is a rare complication, the potential for this to be life threatening makes prevention and early detection of this condition essential. This condition should be suspected when patients experience sudden onset respiratory distress and/or experience a neurological event in the setting of a known risk factor. Treatment options include Durant’s maneuver; left-lateral decubitus, head-down positioning; to decrease air entry into the right ventricle outflow tract, hyperbaric therapy, 100% O2 and supportive care. PMID:28115731

  20. Circulation in a Short Cylindrical Couette System

    Energy Technology Data Exchange (ETDEWEB)

    Akira Kageyama; Hantao Ji; Jeremy Goodman

    2003-07-08

    In preparation for an experimental study of magnetorotational instability (MRI) in liquid metal, we explore Couette flows having height comparable to the gap between cylinders, centrifugally stable rotation, and high Reynolds number. Experiments in water are compared with numerical simulations. The flow is very different from that of an ideal, infinitely long Couette system. Simulations show that endcaps co-rotating with the outer cylinder drive a strong poloidal circulation that redistributes angular momentum. Predicted toroidal flow profiles agree well with experimental measurements. Spin-down times scale with Reynolds number as expected for laminar Ekman circulation; extrapolation from two-dimensional simulations at Re less than or equal to 3200 agrees remarkably well with experiment at Re approximately equal to 106. This suggests that turbulence does not dominate the effective viscosity. Further detailed numerical studies reveal a strong radially inward flow near both endcaps. After turning vertically along the inner cylinder, these flows converge at the midplane and depart the boundary in a radial jet. To minimize this circulation in the MRI experiment, endcaps consisting of multiple, differentially rotating rings are proposed. Simulations predict that an adequate approximation to the ideal Couette profile can be obtained with a few rings.

  1. The protein corona of circulating PEGylated liposomes.

    Science.gov (United States)

    Palchetti, Sara; Colapicchioni, Valentina; Digiacomo, Luca; Caracciolo, Giulio; Pozzi, Daniela; Capriotti, Anna Laura; La Barbera, Giorgia; Laganà, Aldo

    2016-02-01

    Following systemic administration, liposomes are covered by a 'corona' of proteins, and preserving the surface functionality is challenging. Coating the liposome surface with polyethylene glycol (PEG) is the most widely used anti-opsonization strategy, but it cannot fully preclude protein adsorption. To date, protein binding has been studied following in vitro incubation to predict the fate of liposomes in vivo, while dynamic incubation mimicking in vivo conditions remains largely unexplored. The main aim of this investigation was to determine whether shear stress, produced by physiologically relevant dynamic flow, could influence the liposome-protein corona. The corona of circulating PEGylated liposome was thoroughly compared with that formed by incubation in vitro. Systematic comparison in terms of size, surface charge and quantitative composition was made by dynamic light scattering, microelectrophoresis and nano-liquid chromatography tandem mass spectrometry (nanoLC-MS/MS). Size of coronas formed under static vs. dynamic incubation did not appreciably differ from each other. On the other side, the corona of circulating liposomes was more negatively charged than its static counterpart. Of note, the variety of protein species in the corona formed in a dynamic flow was significantly wider. Collectively, these results demonstrated that the corona of circulating PEGylated liposomes can be considerably different from that formed in a static fluid. This seems to be a key factor to predict the biological activity of a liposomal formulation in a physiological environment.

  2. Elevated circulating somatostatin levels in acromegaly.

    Science.gov (United States)

    Arosio, M; Porretti, S; Epaminonda, P; Giavoli, C; Gebbia, C; Penati, C; Beck-Peccoz, P; Peracchi, M

    2003-06-01

    GH increases hypothalamic somatostatin (SS) synthesis and secretion but it is unknown if chronic GH excess, as found in acromegaly, may influence circulating SS levels, that are mainly of enteropancreatic source and affect several gastrointestinal functions, including motility. Circulating SS occurs in several post-translational forms including somatostatin-14 (SS-14), somatostatin-28 (SS-28) and other small peptides. The aim of the present study was to characterize the fasting and postprandial pattern of plasma circulating somatostatin in normal subjects and patients with acromegaly. Fasting total SS and SS-28 levels were measured in 32 subjects, 16 acromegalic patients with a new diagnosis (A) (8 F, 8 M, median age 48) and 16 matched healthy volunteers (C) (8 F, 8 M, median age 45). SS was also determined after a standard solid-liquid meal (550 kCal) in 24 of the subjects (12 C and 12 A). Fasting SS and SS-28 were significantly higher in acromegalic patients as compared to healthy subjects. In the former, a positive correlation was found between IGF-I and SS levels (r = 0.525 p acromegaly. Excess GH/IGF-I could be a causal factor in somatostatin hypersecretion. Conceivably this abnormality might play a role in some alterations of gastrointestinal function of acromegalic patients such as prolonged bowel transit.

  3. Global Circulation and Impact of Plasmaspheric Plumes

    Science.gov (United States)

    Moore, Thomas E.; Fok, Mei-Ching; Chen, Sheng-Hsiem; Delcourt, Dominique C.; Fedder, Joel A.; Slinker, Steven P.

    2008-01-01

    We report results from the global circulation model of Lyon, Fedder, and Mobarry with an embedded model of the inner magnetosphere including the plasmasphere. The combination is used to initiate large numbers of representative protons on the geosynchronous orbit L shell, to assign particle weightings, to track their: subsequent trajectories in the 3D fields. This permits us to study the global circulation of plasmaspheric plumes and to compare these with Polar observations from the dayside magnetopause region . A range of events is studied from an isolated period of SBz in the solar wind,to a large storm sequence. We consider effects on circulating plasma reaching the dayside reconnection X-line, the population of the plasma sheet with ionospheric protons and the generation of ring current pressure from this source, compared with solar wind, polar wind, and auroral wind sources. We find that the transient plasmaspheric plume source is large in terms of total fluence, but of modest proportions in terms of contribution to the ring current. Implications of this and other results for improved space weather modeling and prediction will be discussed.

  4. When Prostate Cancer Circulates in the Bloodstream

    Directory of Open Access Journals (Sweden)

    Virginie Vlaeminck-Guillem

    2015-10-01

    Full Text Available Management of patients with prostate cancer is currently based on imperfect clinical, biological, radiological and pathological evaluation. Prostate cancer aggressiveness, including metastatic potential, remains difficult to accurately estimate. In an attempt to better adapt therapeutics to an individual (personalized medicine, reliable evaluation of the intrinsic molecular biology of the tumor is warranted, and particularly for all tumor sites (primary tumors and secondary sites at any time of the disease progression. As a consequence of their natural tendency to grow (passive invasion or as a consequence of an active blood vessel invasion by metastase-initiating cells, tumors shed various materials into the bloodstream. Major efforts have been recently made to develop powerful and accurate methods able to detect, quantify and/or analyze all these circulating tumor materials: circulating tumors cells, disseminating tumor cells, extracellular vesicles (including exosomes, nucleic acids, etc. The aim of this review is to summarize current knowledge about these circulating tumor materials and their applications in translational research.

  5. 19 CFR 207.63 - Circulation of draft questionnaires.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 3 2010-04-01 2010-04-01 false Circulation of draft questionnaires. 207.63... SUBSIDIZED EXPORTS TO THE UNITED STATES Five-Year Reviews § 207.63 Circulation of draft questionnaires. (a) The Director shall circulate draft questionnaires to the parties for comment in each full review....

  6. Circulator Integrated in Low Temperature Co-fired Ceramics Technology

    NARCIS (Netherlands)

    Dijk, R. van; Bent, G. van der; Ashari, M.; McKay, M.

    2014-01-01

    We present a demonstration of an integrated circulator for TR modules using low temperature co-fired ceramic (LTCC) technology. Two different circulators have been realised to be used in TR modules in two different frequency bands, C-and Ku-band. The circulator is a three-port junction microstrip ty

  7. Clinical profile and prognosis of patients with posterior circulation stroke

    Directory of Open Access Journals (Sweden)

    Kavita J. Rawat

    2016-12-01

    Conclusions: Posterior circulation stroke present with a wide variety of symptoms. Episodes are often staggering and more protracted than those of anterior circulation stroke. Further studies are needed to determine the safest and most effective treatment modalities for the various types of posterior circulation stroke. [Int J Res Med Sci 2016; 4(12.000: 5159-5164

  8. Computer-aided design of stripline ferrite junction circulators

    Science.gov (United States)

    Uzdy, Z.

    1980-01-01

    A general design procedure is presented for stripline Y-junction circulators employing solid dielectric between ground planes. The resonator design and impedance matching are derived in a form suitable for computer evaluation. The procedure is applicable to cases where either the circulator bandwidth or the ground plane spacing is specified. An experimental S-band switching circulator design illustrates the technique.

  9. Algorithms for Finding the Inverses of Factor Block Circulant Matrices

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this paper, algorithms for finding the inverse of a factor block circulant matrix,a factor block retrocirculant matrix and partitioned matrix with factor block circulant blocks over the complex field are presented respectively. In addition, two algorithms for the inverse of a factor block circulant matrix over the quaternion division algebra are proposed.

  10. PARAMETERS OF WATER CIRCULATION NETWORK FOR A DISTRICT HEATING AND COOLING SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In a district heating and cooling system, i.e. Beijing combined heating cooling and power (CHCP) system studied here, high temperature water generated by two cogeneration plants circulates through a network between the plants and heat substations. At heat substations, supply water of high temperature from the network drives absorption chillers for air-conditioning in summer and meets space heating demands in winter or domestic hot water demands by heat exchangers in the whole year. The parameters, i.e. supply/return water temperature in the network, has a great impact on primary energy consumption (PEC) of the absorption chillers, circulation pumps and domestic hot water (DHW), which is studied in this paper.

  11. Development of an Internally Circulating Fluidized Bed Membrane Reactor for Hydrogen Production from Natural Gas

    Institute of Scientific and Technical Information of China (English)

    XIE Dong-lai; GRACE John R; LIM C Jim

    2006-01-01

    An innovative Internally Circulating Fluidized Bed Membrane Reactor (ICFBMR) was designed and operated for ultra-pure hydrogen production from natural gas. The reactor includes internal catalyst solids circulation for conveying heat between a reforming zone and an oxidation zone. In the reforming zone, catalyst particles are transported upwards by reactant gas where steam reforming reactions are taking place and hydrogen is permeating through the membrane surfaces. Air is injected into the oxidation zone to generate heat which is carried by catalyst particles to the reforming zone supporting the endothermic steam reforming reaction. The technology development process is introduced: cold model test,pilot plant and industrial demonstration unit. The process flow diagram and key components of each unit are described.The ICFBMR process has the potential to provide improved performance relative to conventional SMR fixed-bed tubular reactors.

  12. Elevated levels of circulating DNA in cardiovascular disease patients: metagenomic profiling of microbiome in the circulation.

    Science.gov (United States)

    Dinakaran, Vasudevan; Rathinavel, Andiappan; Pushpanathan, Muthuirulan; Sivakumar, Ramamoorthy; Gunasekaran, Paramasamy; Rajendhran, Jeyaprakash

    2014-01-01

    Cardiovascular diseases (CVDs) are the leading cause of death worldwide. An expanding body of evidence supports the role of human microbiome in the establishment of CVDs and, this has gained much attention recently. This work was aimed to study the circulating human microbiome in CVD patients and healthy subjects. The levels of circulating cell free DNA (circDNA) was higher in CVD patients (n = 80) than in healthy controls (n = 40). More specifically, the relative levels of circulating bacterial DNA and the ratio of 16S rRNA/β-globin gene copy numbers were higher in the circulation of CVD patients than healthy individuals. In addition, we found a higher circulating microbial diversity in CVD patients (n = 3) in comparison to healthy individuals (n = 3) by deep shotgun sequencing. At the phylum level, we observed a dominance of Actinobacteria in CVD patients, followed by Proteobacteria, in contrast to that in healthy controls, where Proteobacteria was predominantly enriched, followed by Actinobacteria. The circulating virome in CVD patients was enriched with bacteriophages with a preponderance of Propionibacterium phages, followed by Pseudomonas phages and Rhizobium phages in contrast to that in healthy individuals, where a relatively greater abundance of eukaryotic viruses dominated by Lymphocystis virus (LCV) and Torque Teno viruses (TTV) was observed. Thus, the release of bacterial and viral DNA elements in the circulation could play a major role leading to elevated circDNA levels in CVD patients. The increased circDNA levels could be either the cause or consequence of CVD incidence, which needs to be explored further.

  13. Formation of germline chimera Gaok chicken used circulation primordial germ cells (circulation PGCs fresh and thawed

    Directory of Open Access Journals (Sweden)

    Kostaman T

    2014-03-01

    Full Text Available Formation of germline chimeras by transfer of chicken primordial germ cells (PGCs is one of the effective techniques for preservation and regeneration of genetic resources in chickens. This study attempted to form germline chimeras of Gaok chicken buy purifying circulated PGCs of donor embryo before it is transferred to the recipient (White Leghorn chickens=WL and studied the ability of recipient embryo on survival in incubators, and hatchability. This study used 200 fertile eggs of Gaok and 90 fertile WL breed all of the eggs was incubated at 380C and 60% humidity in a portable incubator. PGCs-circulation of the blood collected Gaok embryos at stage 14-16 were taken from the dorsal aorta, and then purified by centrifugation method using nycodenz. PGCs-circulation results further purification frozen in liquid nitrogen before being transferred to the recipient embryo. The results showed that for the development of embryos transferred to the fresh circulation of PGCs-circulation as many as 25 cells can survive up to day 14, while one of the transferred of 50 and 100 cells into recipient embryos was hatched (10%. On the contrari recipient embryos that are transferred to the frozen PGCs-circulation the embryos development was shorter, and only survived until day 10th (treatment 25 cells, day 14th (treatment of 50 cells and day 17th (treatment of 100 cells. It is concluded that the amount of PGCs-circulation embryos transferred to the recipient is one factor that influence the success of the development germline chimeras.

  14. Iatrogenic systemic air embolism treated with hyperbaric oxygen therapy

    DEFF Research Database (Denmark)

    Jørgensen, Thomas Bech; Sørensen, Allan Martini Ibsen; Jansen, Erik C.

    2008-01-01

    Air embolism is a rare and potentially severe complication of surgical and invasive procedures. Emboli large enough to produce symptoms require immediate treatment because of the risk of 'gas lock' in the right side of the heart and subsequent circulatory failure. If air is transmitted to the art...... to the arterial circulation through a shunt, it may cause cerebral emboli with neurological symptoms. We present two cases with venous air emboli and concurrent cerebral arterial emboli. Both patients were successfully treated with hyperbaric oxygen therapy Udgivelsesdato: 2008/4...

  15. Direct inversion of circulation and mixing from tracer measurements - Part 1: Method

    Science.gov (United States)

    von Clarmann, Thomas; Grabowski, Udo

    2016-11-01

    From a series of zonal mean global stratospheric tracer measurements sampled in altitude vs. latitude, circulation and mixing patterns are inferred by the inverse solution of the continuity equation. As a first step, the continuity equation is written as a tendency equation, which is numerically integrated over time to predict a later atmospheric state, i.e., mixing ratio and air density. The integration is formally performed by the multiplication of the initially measured atmospheric state vector by a linear prediction operator. Further, the derivative of the predicted atmospheric state with respect to the wind vector components and mixing coefficients is used to find the most likely wind vector components and mixing coefficients which minimize the residual between the predicted atmospheric state and the later measurement of the atmospheric state. Unless multiple tracers are used, this inversion problem is under-determined, and dispersive behavior of the prediction further destabilizes the inversion. Both these problems are addressed by regularization. For this purpose, a first-order smoothness constraint has been chosen. The usefulness of this method is demonstrated by application to various tracer measurements recorded with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). This method aims at a diagnosis of the Brewer-Dobson circulation without involving the concept of the mean age of stratospheric air, and related problems like the stratospheric tape recorder, or intrusions of mesospheric air into the stratosphere.

  16. Seasonal overturning circulation in the Red Sea: 1. Model validation and summer circulation

    KAUST Repository

    Yao, Fengchao

    2014-04-01

    The overturning circulation in the Red Sea exhibits a distinct seasonally reversing pattern and is studied using high-resolution MIT general circulation model simulations. In the first part of this study, the vertical and horizontal structure of the summer overturning circulation and its dynamical mechanisms are presented from the model results. The seasonal water exchange in the Strait of Bab el Mandeb is successfully simulated, and the structures of the intruding subsurface Gulf of Aden intermediate water are in good agreement with summer observations in 2011. The model results suggest that the summer overturning circulation is driven by the combined effect of the shoaling of the thermocline in the Gulf of Aden resulting from remote winds in the Arabian Sea and an upward surface slope from the Red Sea to the Gulf of Aden set up by local surface winds in the Red Sea. In addition, during late summer two processes associated, respectively, with latitudinally differential heating and increased salinity in the southern Red Sea act together to cause the reversal of the contrast of the vertical density structure and the cessation of the summer overturning circulation. Dynamically, the subsurface northward pressure gradient force is mainly balanced by vertical viscosity resulting from the vertical shear and boundary friction in the Strait of Bab el Mandeb. Unlike some previous studies, the three-layer summer exchange flows in the Strait of Bab el Mandeb do not appear to be hydraulically controlled.

  17. Explicit Determinants of the RFPrLrR Circulant and RLPrFrL Circulant Matrices Involving Some Famous Numbers

    Directory of Open Access Journals (Sweden)

    Tingting Xu

    2014-01-01

    Full Text Available Circulant matrices may play a crucial role in solving various differential equations. In this paper, the techniques used herein are based on the inverse factorization of polynomial. We give the explicit determinants of the RFPrLrR circulant matrices and RLPrFrL circulant matrices involving Fibonacci, Lucas, Pell, and Pell-Lucas number, respectively.

  18. Effect of vegetation on the Late Miocene ocean circulation

    Directory of Open Access Journals (Sweden)

    G. Lohmann

    2006-08-01

    Full Text Available A weak and shallow thermohaline circulation in the North Atlantic Ocean is related to an open Central American gateway and exchange with fresh Pacific waters. We estimate the effect of vegetation on the ocean general circulation using the atmospheric circulation model simulations for the Late Miocene climate. Caused by an increase in net evaporation in the Miocene North Atlantic, the North Atlantic water becomes more saline which enhances the overturning circulation and thus the northward heat transport. This effect reveals a potentially important feedback between the ocean circulation, the hydrological cycle and the land surface cover for Cenozoic climate evolution.

  19. Air filtration and indoor air quality

    DEFF Research Database (Denmark)

    Bekö, Gabriel

    2006-01-01

    decent ventilation and air cleaning/air filtration, high indoor air quality cannot be accomplished. The need for effective air filtration has increased with increasing evidence on the hazardous effects of fine particles. Moreover, the air contains gaseous pollutants, removal of which requires various air....... These contradictions should motivate manufacturers and researchers to develop new efficient filtration techniques and/or improve the existing ones. Development of low polluting filtration techniques, which are at the same time easy and inexpensive to maintain is the way forward in the future....

  20. Design and Fabrication of Millimeter Wave Hexagonal Nano-Ferrite Circulator on Silicon CMOS Substrate

    Science.gov (United States)

    Oukacha, Hassan

    The rapid advancement of Complementary Metal Oxide Semiconductor (CMOS) technology has formed the backbone of the modern computing revolution enabling the development of computationally intensive electronic devices that are smaller, faster, less expensive, and consume less power. This well-established technology has transformed the mobile computing and communications industries by providing high levels of system integration on a single substrate, high reliability and low manufacturing cost. The driving force behind this computing revolution is the scaling of semiconductor devices to smaller geometries which has resulted in faster switching speeds and the promise of replacing traditional, bulky radio frequency (RF) components with miniaturized devices. Such devices play an important role in our society enabling ubiquitous computing and on-demand data access. This thesis presents the design and development of a magnetic circulator component in a standard 180 nm CMOS process. The design approach involves integration of nanoscale ferrite materials on a CMOS chip to avoid using bulky magnetic materials employed in conventional circulators. This device constitutes the next generation broadband millimeter-wave circulator integrated in CMOS using ferrite materials operating in the 60GHz frequency band. The unlicensed ultra-high frequency spectrum around 60GHz offers many benefits: very high immunity to interference, high security, and frequency re-use. Results of both simulations and measurements are presented in this thesis. The presented results show the benefits of this technique and the potential that it has in incorporating a complete system-on-chip (SoC) that includes low noise amplifier, power amplier, and antenna. This system-on-chip can be used in the same applications where the conventional circulator has been employed, including communication systems, radar systems, navigation and air traffic control, and military equipment. This set of applications of

  1. Attempts on cardoon gasification in two different circulating fluidized beds

    Directory of Open Access Journals (Sweden)

    Chr. Christodoulou

    2014-11-01

    Full Text Available Few tests have been carried out in order to evaluate the use of cardoon in gasification and combustion applications most of the researchers dealt with agglomeration problems. The aim of this work is to deal with the agglomeration problem and to present a solution for the utilization of this biofuel at a near industrial application scale. For this reason, two experiments were conducted, one in TU Delft and one in Centre for Research and Technology Hellas (CERTH, using fuel cardoon and 50% w/w cardoon blended with 50% w/w giant reed respectively. Both experimental campaigns were carried out in similar atmospheric circulating fluidized bed gasifiers. Apart from the feedstock, the other differences were the gasification medium and the bed material used in each trial. The oxidizing agent at TUD׳s run was O2/steam, whereas CERTH׳s tests used air. When experiments with the cardoon 50% w/w–giant reed 50% w/w blend were performed no agglomeration problems were presented. Consequently, gasification could be achieved in higher temperature than that of pure cardoon which led to the reduction of tar concentration.

  2. Olive cake combustion in a circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Topal, H.; Durmaz, A. [Gazi Univ, Ankara (Turkey). Dept. of Mechanical Engineering; Atimtay, A.T. [Middle East Technical Univ., Ankara (Turkey). Dept. of Environmental Engineering

    2002-07-01

    This paper presents the results of a study in which an environmentally sound technology was developed for biomass usage for energy production in Turkey. A circulating fluidized bed of 125 mm diameter and 1,800 mm height was used to determine the combustion characteristics of olive cake (OC) produced in Turkey. Olive cake, an olive oil milling waste product, is available in large amounts at a very low cost. Efficient use of OC in energy production solves the problem of waste management and contributes to meeting targets of the Kyoto Protocol. In this study, olive cake alone and olive cake plus lignite mixtures were burned in separate experiments and in various ratios. A new feeding mechanism was developed to feed the olive cake to the bed. On-line concentrations of oxygen, sulphur dioxide, carbon dioxide, carbon monoxide, nitrogen oxides and total hydrocarbons were measured in the flue gas along with temperature distribution in the bed. Emissions were compared with national standards and combustion efficiency of the olive cake plus lignite coal mixtures and olive cake alone were calculated. The optimum operating parameters were described. OC burned with 94 to 98.5 per cent efficiency. The combustion efficiency increased with increased excess air ratio because volatiles released from the fuel were burned more completely. 3 refs., 5 tabs., 6 figs.

  3. Linear theory of the urban heat island circulation

    Science.gov (United States)

    Oerlemans, J.

    A linear time-dependent model of the urban heat island circulation is developed for use in situations with a marked inversion. It has the external and first-internal gravity wave modes as basic dynamic ingredients (the inversion is treated as a 'free' surface). The background wind field may vary with height and in time, and the Coriolis acceleration, though not important in most cases, is taken into account. The model equations are formulated in two-D (horizontal) Fourier space, permitting a fully implicit scheme to be used. Large time steps can then be employed, so that the external mode is implicitly in balance, while the internal mode slowly evolves. The value of the model lies in its efficiency: with 1600 two-D Fourier components and a 1-h time step, a 10-h integration typically takes 20 s of central processor time on a Cyber 175. The model is thus suitable for use in connection with operational air quality models running on smaller computers. Another advantage over more complete mesoscale atmospheric models is that initialization is very simple. Various examples are discussed to illustrate the performance of the model.

  4. Gas cooled fast breeder reactor design for a circulator test facility (modified HTGR circulator test facility)

    Energy Technology Data Exchange (ETDEWEB)

    1979-10-01

    A GCFR helium circulator test facility sized for full design conditions is proposed for meeting the above requirements. The circulator will be mounted in a large vessel containing high pressure helium which will permit testing at the same power, speed, pressure, temperature and flow conditions intended in the demonstration plant. The electric drive motor for the circulator will obtain its power from an electric supply and distribution system in which electric power will be taken from a local utility. The conceptual design decribed in this report is the result of close interaction between the General Atomic Company (GA), designer of the GCFR, and The Ralph M. Parson Company, architect/engineer for the test facility. A realistic estimate of total project cost is presented, together with a schedule for design, procurement, construction, and inspection.

  5. Effect of slip on circulation inside a droplet

    CERN Document Server

    Thalakkottor, Joseph J

    2013-01-01

    Internal recirculation in a moving droplet plays an important role in several droplet-based microfluidic devices as it enhances mixing, chemical reaction and heat transfer. The occurrence of fluid slip at the wall, which becomes prominent at high shear rates and lower length scales, results in a significant change in droplet circulation. Using molecular dynamics (MD) simulations, the presence of circulation in droplets is demonstrated and quantified. Circulation is shown to vary inversely with slip length, which is a measure of interface wettability. A simple circulation model is established that captures the effect of slip on droplet circulation. Scaling parameters for circulation and slip length are identified from the circulation model which leads to the collapse of data for droplets with varying aspect ratio (AR) and slip length. The model is validated using continuum and MD simulations and is shown to be accurate for droplets with high AR.

  6. Air pollution

    Energy Technology Data Exchange (ETDEWEB)

    1974-12-01

    Air pollution conditions in Iwakuni city were monitored at 9 monitoring stations, and 21 locations where sulfur oxides were measured by the lead peroxide candle method, and 13 locations where particulates concentrations were determined by the deposit cage method. The average SO/sub x/ concentrations in 1973 measured by the lead peroxide candle method ranged from 0.17 mg sulfur trioxide/day/100 sq cm at the Miso Office to 0.58 mg SO/sub 3//day/100 sq cm at Mitsui Sekiyu Shataku. The average SO/sub x/ concentrations measured by the conductivity method ranged from 0.021 ppM at Kazuki Kominkan to 0.037 ppM at the Higashi Fire Department. Only 58% of a total of 264 measurement days gave hourly average concentrations below the environmental standard of 0.04 ppM at the Higashi Fire Deparment. The average airborne particulate concentrations ranged from 0.050 mg/cu m at Totsu Kominkan to 0.056 mg/cu at the Higashi Fire Department. The average nitrogen oxides concentrations measured by the Saltzman method ranged from 0.007 ppM to 0.061 ppM. The average oxidant concentrations at the Iwakuni Municipal Office and Kazuki Kominkan were 0.028 ppM and 0.037 ppM, respectively.

  7. Atmospheric General Circulation Changes under Global Warming

    Science.gov (United States)

    Palipane, Erool

    The work in this thesis is mainly two-fold. First we study the internal variability of the general circulation and focus our study on the annular modes and how important it is to simulate the subsynoptic scales in the circulation. In the next major section we will try to understand the mechanisms of the forced response and the mechanisms leading towards the jet shift from transient evolution in Atmospheric general circulation models. In the first part, in an attempt to assess the benefit of resolving the sub-synoptic to mesoscale processes, the spatial and temporal characteristics of the Annular Modes (AMs), in particular those related to the troposphere-stratosphere interaction, are evaluated for moderate- and high-horizontal resolution simulations with a global atmospheric general circulation model (AGCM), in comparison with the ERA40 re- analysis. Relative to the CMIP-type climate models, the IFS AGCM demonstrates notable improvement in capturing the key characteristics of the AMs. Notably, the performance with the high horizontal resolution version of the model is systematically superior to the moderate resolution on all metrics examined, including the variance of the AMs at different seasons of the year, the intrinsic e-folding time scales of the AMs, and the downward influence from the stratosphere to troposphere in the AMs. Moreover, the high-resolution simulation with a greater persistence in the intrinsic variability of the SAM projects an appreciably larger shift of the surface westerly wind during the Southern Hemisphere summer under climate change. In the second part, the response of the atmospheric circulation to greenhouse gas-induced SST warming is investigated using large ensemble experiments with two AGCMs, with a focus on the robust feature of the poleward shift of the eddy driven jet. In these experiments, large ensembles of simulations are conducted by abruptly switching the SST forcing on from January 1st to focus on the wintertime circulation

  8. Reduction of indoor particles concentration using re-circulating filtration units in Danish dwellings

    DEFF Research Database (Denmark)

    Spilak, Michal; Frederiksen, Marie; Karottki, Gabriela D.;

    2012-01-01

    Exposure to particulate matter has been shown to be associated with an increased risk of cardiovascular and respiratory diseases. The indoor environment contributes significantly to the total exposure to air pollution because of the many hours spent here, quantity of sources and low ventilation....... This exposure can be reduced by using re-circulating filtration units, limiting the impact of outdoor pollution penetration, indoor emissions and decomposition of dust on heated surfaces. The objective of this study was to investigate whether reducing the indoor particulate concentration, by means of specially...

  9. Pure midbrain ischemia and hypoplastic vertebrobasilar circulation.

    Science.gov (United States)

    Gilberti, Nicola; Gamba, Massimo; Costa, Angelo; Vergani, Veronica; Spezi, Raffaella; Pezzini, Alessandro; Volonghi, Irene; Mardighian, Dikran; Gasparotti, Roberto; Padovani, Alessandro; Magoni, Mauro

    2014-02-01

    Isolated midbrain infarction is rare and little is known about etiology and patient's long-term follow up. We aimed to describe the clinical features, the causative diseases and the outcome of patients with isolated midbrain infarction who were admitted to our center, focusing on vascular abnormalities of posterior circulation. All patients with first acute ischemic stroke limited to the midbrain were included and their demographic features, neurological symptoms, neuroimaging data, and cardiovascular risk factors were recorded. Functional outcome, using modified Rankin scale, was assessed at discharge and at the 3 month follow up evaluation. We found nine patients with acute isolated midbrain infarction, representing 0.61 % of all ischemic stroke admitted to our center. The most common cause of stroke was small-vessel disease (88.8 %). At stroke onset, none of the patients had consciousness disturbances, and four patients (44.4 %) had gait impairment, five patients (55.5 %) presented with diplopia due to involvement of the third nerve or fascicular type of third-nerve palsy, seven patients (77.7 %) had vascular anomalies of vertebrobasilar circulation: the most frequent was vertebral artery hypoplasia [four patients (44.4 %)]. At follow up evaluation, seven patients (77.7 %) had a good functional outcome and no patients experienced recurrence of cerebrovascular events. As isolated midbrain infarction is uncommon, specific ocular motor signs, mainly third-nerve palsy, may help to identify and localize the mesencephalic infarct. Abnormalities in vertebrobasilar circulation, such as hypoplastic basilar or vertebral artery, are frequently associated with isolated midbrain ischemia. The hypoplastic vertebrobasilar system may predispose to posterior ischemic stroke.

  10. Microsurgical management of posterior circulation aneurysms

    Directory of Open Access Journals (Sweden)

    SHI Xiang-en

    2012-02-01

    Full Text Available Objective To retrospectively analyze effective methods for surgical management of posterior circulation aneurysms. Methods There were 42 patients with posterior circulation aneurysms [26 cases of basilar aneurysm (27 aneurysms, 16 cases of vertebral aneurysm (17 aneurysms]. There were 15 patients underwent bypass surgery [4 external carotid artery-P2 segment of posterior cerebral artery (ECA-P2, 2 internal carotid artery-P2 segment of posterior cerebral artery (ICA-P2, 2 internal maxillary artery-P2 segment of posterior cerebral artery (IMA-P2, 2 intracranial segment of vertebral artery-extracranial segment of vertebral artery, 5 occipital artery-posterior inferior cerebellar artery (OA-PICA] and 27 patients underwent simple surgical clipping. Results Activities of daily life of 37 patients recovered to normal (14 patients with aneurysm on the top of basilar artery, 3 with aneurysm on the trunk of basilar artery, 9 with vertebral aneurysm, 5 with posterior inferior cerebellar artery aneurysm, 4 with aneurysm on the junction of P1-P2 segment of posterior cerebral artery, 1 with superior cerebellar artery, and 1 with anterior inferior cerebellar aneurysm. None of them occurred operation-related neurological dysfunction. The recovery rate was 88.09% . Among the other patients, 1 with aneurysm on the top of basilar artery presented severe signs and symptoms of neurological defect and cannot take care of oneself, 2 patients (1 with aneurysm on the top of basilar artery, 1 with aneurysm on the trunk of basilar artery occurred brain stem hemorrhage after operation, and died at perioperative period, 2 with vertebral aneurysm relapsed and was cured after treatment. Conclusion Posterior circulation aneurysm which is not suitable for surgical clipping can be treated with intra? and extra?cranial vessel bypass. It may avoid the risk of surgical clipping of aneurysm.

  11. Bay of Campeche circulation: An update

    Science.gov (United States)

    Vázquez de la Cerda, A. M.; Reid, R. O.; DiMarco, S. F.; Jochens, A. E.

    We address four independent sources of observational evidence pertaining to circulation in the Bay of Campeche (BOC), located south of 23°N in the western Gulf of Mexico, with the objective of characterizing its mean circulation, its variability, and the probable forcing thereof. The observational information includes historic hydrographic and dissolved oxygen data, Lagrangian current data, satellite-derived sea surface height anomaly (SSHA), and special observations of marine winds in the BOC. The hydrographic data reveals that the mean surface circulation relative to 425 db and to 800 db includes a weak cyclone with cyclic transport of about 4×106 m3 · s-1. Ten years of near-surface drifter observations shows a statistically meaningful mean cyclonic pattern of current with westward intensification that is consistent with the mean surface dynamic topography relative to 800 db. Observations of mean currents in the BOC at 900 m based on deep floats by G. L. Weatherly and others allows estimation of the current shear from the Lagrangian data and this is geostrophically consistent with that from the dynamic topography relative to 800 m. The mean cyclonic wind stress curl field deduced from two sources of marine wind data indicate a forced Sverdrup transport consistent with that observed. Moreover a seasonal cycle is suggested in the near surface drifter data that is coherent with the seasonal signal in the wind stress curl. Finally, the historic SSHA for a period of over 8 years in the 1990s allows a characterization of the dominant empirical spatial patterns and their temporal variability.

  12. On circulating power of steady state tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Kimitaka [National Inst. for Fusion Science, Nagoya (Japan); Itoh, Sanae; Fukuyama, Atsushi; Yagi, Masatoshi

    1996-03-01

    Circulating power for the sustenance and profile control of the steady state tokamak plasmas is discussed. The simultaneous fulfillment of the MHD stability at high beta value, the improved confinement and the stationary equilibrium requires the rotation drive as well as the current drive. In addition to the current drive efficiency, the efficiency for the rotation drive is investigated. The direct rotation drive by the external torque, such as the case of beam injection, is not efficient enough. The mechanism and the magnitude of the spontaneous plasma rotation are studied. (author)

  13. Transients in a circulating fluidized bed boiler

    Science.gov (United States)

    Baskakov, A. P.; Munts, V. A.; Pavlyuk, E. Yu.

    2013-11-01

    Transients in a circulating fluidized bed boiler firing biomass are considered. An attempt is made to describe transients with the use of concepts applied in the automatic control theory. The parameters calculated from an analysis of unsteady heat balance equations are compared with the experimental data obtained in the 12-MW boiler of the Chalmers University of Technology. It is demonstrated that these equations describe the transient modes of operation with good accuracy. Dependences for calculating the time constants of unsteady processes are obtained.

  14. Non-singular circulant graphs and digraphs

    CERN Document Server

    Lal, A K

    2011-01-01

    We give necessary and sufficient conditions for a few classes of circulant graphs/digraphs to be singular. We also give two generalizations of the above graphs/digraphs, namely $(r,s,t)$-digraphs for non-negative integers $r,s$ and $t$, and the digraph $C_n^{i,j,k,l}$ with certain restrictions. A necessary and sufficient condition for the digraphs $C_n^{i,j,k,l}$ to be singular is obtained. Some necessary conditions are given under which the $(r,s,t)$-digraphs are singular.

  15. Is the thermohaline circulation really at risk?

    OpenAIRE

    Quadfasel, Detlef

    2012-01-01

    Changes in thermohaline circulation (THC) have been known to change the European and Arctic climate within decades. Knowing if, when, and how a major change in the THC might occur in the mid-term might enable both the public and the private sectors to understand the risks, time horizon, and possible scenarios of major changes in the climate and to adapt to them. The THOR project has been running from 2008 to 2012 and has been investigating on determining how the THC impacts climate stabili...

  16. Nucla circulating atmospheric fluidized bed demonstration project

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-31

    During the fourth quarter of 1990, steady-state performance testing at the Nucla Circulating Fluidized Bed (CFB) resumed under sponsorship of the US Department of Energy. Co-sponsorship of the Demonstration Test Program by the Electric Power Research Institute (EPRI) was completed on June 15, 1990. From October through December, 1990, Colorado-Ute Electric Association (CUEA) completed a total of 23 steady-state performance tests, 4 dynamic tests, and set operating records during November and December as the result of improved unit operating reliability. Highlight events and achievements during this period of operation are presented.

  17. Circulant states with positive partial transpose

    Science.gov (United States)

    Chruściński, Dariusz; Kossakowski, Andrzej

    2007-09-01

    We construct a large class of quantum d⊗d states which are positive under partial transposition (so called PPT states). The construction is based on certain direct sum decomposition of the total Hilbert space displaying characteristic circular structure—that is why we call them circulant states. It turns out that partial transposition maps any such decomposition into another one and hence both original density matrix and its partially transposed partner share similar cyclic properties. This class contains many well-known examples of PPT states from the literature and gives rise to a huge family of completely new states.

  18. Effects of Buoyancy on Langmuir Circulation

    Institute of Scientific and Technical Information of China (English)

    SONG Jun; SONG Jin-Bao

    2008-01-01

    Based on the Navier-Stokes equation,an equation describing the Langmuir circulation is derived by a perturbation method when the influences of Coriolis force and buoyancy force are both considered.The approach used in the analysis is similar to the works carried out by Craik and Leibovich[J.Fluid Mech.73 (1976)401],Leibovich [J.Fluid Mech.79 (1977) 715]and Huang[J.Fluid Mech.91 (1979) 191].Potential applications of the equation proposed are discussed in the area of Antarctic circumpolar current.

  19. Biodegradable long-circulating polymeric nanospheres.

    Science.gov (United States)

    Gref, R; Minamitake, Y; Peracchia, M T; Trubetskoy, V; Torchilin, V; Langer, R

    1994-03-18

    Injectable nanoparticulate carriers have important potential applications such as site-specific drug delivery or medical imaging. Conventional carriers, however, cannot generally be used because they are eliminated by the reticulo-endothelial system within seconds or minutes after intravenous injection. To address these limitations, monodisperse biodegradable nanospheres were developed from amphiphilic copolymers composed of two biocompatible blocks. The nanospheres exhibited dramatically increased blood circulation times and reduced liver accumulation in mice. Furthermore, they entrapped up to 45 percent by weight of the drug in the dense core in a one-step procedure and could be freeze-dried and easily redispersed without additives in aqueous solutions.

  20. Air Sensor Toolbox

    Science.gov (United States)

    Air Sensor Toolbox provides information to citizen scientists, researchers and developers interested in learning more about new lower-cost compact air sensor technologies and tools for measuring air quality.

  1. GSPEL - Air Filtration Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Evaluation capabilities for air filtration devicesThe Air Filtration Lab provides testing of air filtration devices to demonstrate and validate new or legacy system...

  2. Lead (Pb) Air Pollution

    Science.gov (United States)

    ... States Environmental Protection Agency Search Search Lead (Pb) Air Pollution Share Facebook Twitter Google+ Pinterest Contact Us As ... and protect aquatic and terrestrial ecosystems. Lead (Pb) Air Pollution Lead Air Pollution Basics How does lead get ...

  3. COSTEAU - preheating and cooling by means of underground collectors with water circulation - case study (Perret building at Satigny, Geneva) and generalisation; COSTEAU. Prechauffage et rafraichissement par collecteurs souterrains a eau. Etude de cas (batiment Perret a Satigny, Geneve) et generalisation

    Energy Technology Data Exchange (ETDEWEB)

    Hollmuller, P.; Lachal, B.

    2003-07-01

    Since a couple of years, underground collectors with air circulation have been becoming increasingly popular as a simple means for preheating (at winter time) and cooling (at summer time) of outdoor air ahead of a ventilation system for well insulated buildings. This report considers underground collectors with water circulation used for similar purposes. They are connected to the ventilation system via an air/water heat exchanger. Starting from a case study - one-year detailed in-situ measurements and data analysis from an air-heated office building near Geneva, Switzerland - computerised simulations have been performed as a sensitivity analysis tool as well as to establish recommendations and sizing rules for planners, including cost considerations. In the case study it turned out that the water-circulated underground collector, which is installed right under the basement of this well insulated building, is in thermal contact with the basement. Its main function is to damp the daily temperature oscillation of the inlet ventilation air, bringing the expected thermal comfort improvement in the summer time. However, this underground collector is unable to collect seasonally stored heat from the ground. Hence, in the winter time the main preheating contribution arises from the series-connected heat-recovery unit from the exit air. Numerical simulations show that optimal sizing of underground collectors is essential, and that both the underground collector and the well insulated building as a physical system with thermal inertia have to be simultaneously considered in the optimization process. Optimization also has to include parasitic energy (electricity) needed by fans and pumps. As outdoor air inlet can never be flooded in the case of underground collectors with water circulation the sanitary risk encountered with air-circulated underground collectors does not exist for them. Initial investment cost for water-circulated underground collectors is higher than for a

  4. AirPEx: Air Pollution Exposure Model

    OpenAIRE

    Freijer JI; Bloemen HJTh; de Loos S; Marra M; Rombout PJA; Steentjes GM; Veen MP van; LBO

    1997-01-01

    Analysis of inhalatory exposure to air pollution is an important area of investigation when assessing the risks of air pollution for human health. Inhalatory exposure research focuses on the exposure of humans to air pollutants and the entry of these pollutants into the human respiratory tract. The principal grounds for studying the inhalatory exposure of humans to air pollutants are formed by the need for realistic exposure/dose estimates to evaluate the health effects of these pollutants. T...

  5. AirPEx: Air Pollution Exposure Model

    NARCIS (Netherlands)

    Freijer JI; Bloemen HJTh; Loos S de; Marra M; Rombout PJA; Steentjes GM; Veen MP van; LBO

    1997-01-01

    Analysis of inhalatory exposure to air pollution is an important area of investigation when assessing the risks of air pollution for human health. Inhalatory exposure research focuses on the exposure of humans to air pollutants and the entry of these pollutants into the human respiratory tract. The

  6. Air Pollution Monitoring | Air Quality Planning & Standards ...

    Science.gov (United States)

    2016-06-08

    The basic mission of the Office of Air Quality Planning and Standards is to preserve and improve the quality of our nation's air. To accomplish this, OAQPS must be able to evaluate the status of the atmosphere as compared to clean air standards and historical information.

  7. Weather types in the South Shetlands (Antarctica) using a circulation type approach

    Science.gov (United States)

    Mora, Carla; João Rocha, Maria; Dutra, Emanuel; Trigo, Isabel; Vieira, Gonçalo; Fragoso, Marcelo; Ramos, Miguel

    2010-05-01

    Weather types in the South Shetlands (Antarctica) were defined using an automated method based on the Lamb Weather Type classification scheme (Jones et al. 1993). This is an objective classification originally developed for the British Isles (Jones et al., 1993) and also applied to southeast (Goodess and Palutikof 1998) and northwest Spain (Lorenzo et al, 2009), Portugal (Trigo and DaCamara 2000) and Greece (Maheras et al. 2004) with good results. Daily atmospheric circulation in the South Shetlands region from 1989 to 2009 was classified using a 16-node grid of sea level pressure data from the ERA Interim. The classification is obtained through the comparison of the magnitudes of the directional and rotational components of the geostrophic flow. Basic circulation types were combined into 10 groups of weather types: four directional types (NW, N, S and SW), three anticyclonic types (A, ASW and ANW), and three cyclonic types (C, CSW and CNW). Westerly flow and cyclonic circulation are the most frequent events throughout the year. The sea level pressure field for each weather type is presented and the synoptic characteristics are described. The analysis is based on ERA-Interim fields, including mean sea level pressure, precipitation, cloud cover, humidity and air temperature. Snow thickess modelled using HTESSEL is also considered. Analysis of variance (anova) and multivariate analysis (principal component analysis) are applied to evaluate the characteristics of each weather type. This circulation-type approach showed good results in the past for the downscaling of precipitation in other regions, and we are interested in evaluating the possibilities that the classification offers for downscaling precipitation, but also for snow and air temperature. For this we will be using observational data at test sites in Livingston and Deception islands. We are also motivated by the possibility of using the circulation-type approach as a predictor in statistical downscaling

  8. Glioblastoma Circulating Cells: Reality, Trap or Illusion?

    Directory of Open Access Journals (Sweden)

    A. Lombard

    2015-01-01

    Full Text Available Metastases are the hallmark of cancer. This event is in direct relationship with the ability of cancer cells to leave the tumor mass and travel long distances within the bloodstream and/or lymphatic vessels. Glioblastoma multiforme (GBM, the most frequent primary brain neoplasm, is mainly characterized by a dismal prognosis. The usual fatal issue for GBM patients is a consequence of local recurrence that is observed most of the time without any distant metastases. However, it has recently been documented that GBM cells could be isolated from the bloodstream in several studies. This observation raises the question of the possible involvement of glioblastoma-circulating cells in GBM deadly recurrence by a “homing metastasis” process. Therefore, we think it is important to review the already known molecular mechanisms underlying circulating tumor cells (CTC specific properties, emphasizing their epithelial to mesenchymal transition (EMT abilities and their possible involvement in tumor initiation. The idea is here to review these mechanisms and speculate on how relevant they could be applied in the forthcoming battles against GBM.

  9. Formation and Plasma Circulation of Solar Prominences

    Science.gov (United States)

    Xia, C.; Keppens, R.

    2016-05-01

    Solar prominences are long-lived cool and dense plasma curtains in the hot and rarefied outer solar atmosphere or corona. The physical mechanism responsible for their formation and especially for their internal plasma circulation has been uncertain for decades. The observed ubiquitous downflows in quiescent prominences are difficult to interpret because plasma with high conductivity seems to move across horizontal magnetic field lines. Here we present three-dimensional numerical simulations of prominence formation and evolution in an elongated magnetic flux rope as a result of in situ plasma condensations fueled by continuous plasma evaporation from the solar chromosphere. The prominence is born and maintained in a fragmented, highly dynamic state with continuous reappearance of multiple blobs and thread structures that move mainly downward, dragging along mass-loaded field lines. The circulation of prominence plasma is characterized by the dynamic balance between the drainage of prominence plasma back to the chromosphere and the formation of prominence plasma via continuous condensation. Plasma evaporates from the chromosphere, condenses into the prominence in the corona, and drains back to the chromosphere, establishing a stable chromosphere-corona plasma cycle. Synthetic images of the modeled prominence with the Solar Dynamics Observatory Atmospheric Imaging Assembly closely resemble actual observations, with many dynamical threads underlying an elliptical coronal cavity.

  10. ENDEMIC ORTHOPOXVIRUS CIRCULATING IN PROCYONIDS IN MEXICO.

    Science.gov (United States)

    Gallardo-Romero, Nadia F; Aréchiga-Ceballos, Nidia; Emerson, Ginny L; Martínez-Martínez, Flor O; Doty, Jeffrey B; Nakazawa, Yoshinori J; Rendón-Franco, Emilio; Muñoz-García, Claudia I; Villanueva-García, Claudia; Ramírez-Cid, Citlali; Gama-Campillo, Lilia M; Gual-Sill, Fernando; Aguilar-Setién, Álvaro; Carroll, Darin S

    2016-07-01

    Limited serosurveillance studies suggested that orthopoxviruses (OPXV) are widespread in the US (e.g., Raccoonpox virus, Skunkpox virus, Volepox virus) and Brazil (Vaccinia virus); however, their animal reservoir(s) remain unconfirmed. Mexican mammal diversity includes several species related to those in which evidence for OPXV infections has been found (Oryzomys, Peromyscus, Microtus, and Procyonidae). The presence of these groups of mammals in Mexico and the evidence of their possible involvement in the maintenance of OPXV in nature suggest the same or similar OPXV are circulating in Mexico. We tested 201 sera from 129 procyonids via modified enzyme-linked immunosorbent assay (ELISA) and Western blot (WB) to estimate OPXV antibody prevalence in these animals. We detected a prevalence of 16.67% in Nasua narica (white-nosed coati), 35% in Procyon lotor (raccoon), and 30.4% in Bassariscus astutus (ring-tailed cat) when tested by either ELISA or WB. Western blot results presented protein bands consistent with the size of some OPXV immunodominant bands (14, 18, 32, 36, and 62 kDa). These results support the hypothesis that OPXV circulate in at least three genera of Procyonidae in Central and Southeast Mexico.

  11. The biology of circulating tumor cells.

    Science.gov (United States)

    Pantel, K; Speicher, M R

    2016-03-10

    Metastasis is a biologically complex process consisting of numerous stochastic events which may tremendously differ across various cancer types. Circulating tumor cells (CTCs) are cells that are shed from primary tumors and metastatic deposits into the blood stream. CTCs bear a tremendous potential to improve our understanding of steps involved in the metastatic cascade, starting from intravasation of tumor cells into the circulation until the formation of clinically detectable metastasis. These efforts were propelled by novel high-resolution approaches to dissect the genomes and transcriptomes of CTCs. Furthermore, capturing of viable CTCs has paved the way for innovative culturing technologies to study fundamental characteristics of CTCs such as invasiveness, their kinetics and responses to selection barriers, such as given therapies. Hence the study of CTCs is not only instrumental as a basic research tool, but also allows the serial monitoring of tumor genotypes and may therefore provide predictive and prognostic biomarkers for clinicians. Here, we review how CTCs have contributed to significant insights into the metastatic process and how they may be utilized in clinical practice.

  12. Measurement of cerebral circulation time in man

    Energy Technology Data Exchange (ETDEWEB)

    Celsis, P.; Chan, M.; Marc-Vergnes, J.P.; Leydet, P.; Viallard, G.; Charlet, J.P.; Danet, B.

    1985-05-01

    A simple, inexpensive method for measuring the cerebral circulation time (CCT) was developed. The CCT was considered to be equal to the time that an intravenously injected bolus of sodium pertechnetate Tc 99m took to go from the subclavian artery to the posterior venous confluence. The dilution curves were externally recorded at these two vessels. Particular attention was given to the curve treatment. The computer programmes were specially conceived in order to detect and, if possible, correct the experimental curve defects. Several reliability criteria were also defined in order to test the validity of each measurement. From a physiological point of view, the CCT is equal to the ratio of the global cerebral blood volume to the global cerebral blood flow. Thus, it can be widely applied in clinical research. For example, in a study of the relationship between CCT and age, sex and light cerebrovascular impairment, the technique was sensitive enough to discriminate between healthy subjects and patients suffering from-transient ischemic attack, or regressive stroke, and to show the action of a drug on the cerebral circulation in such patients.

  13. New England Medical Center Posterior Circulation registry.

    Science.gov (United States)

    Caplan, Louis R; Wityk, Robert J; Glass, Thomas A; Tapia, Jorge; Pazdera, Ladislav; Chang, Hui-Meng; Teal, Phillip; Dashe, John F; Chaves, Claudia J; Breen, Joan C; Vemmos, Kostas; Amarenco, Pierre; Tettenborn, Barbara; Leary, Megan; Estol, Conrad; Dewitt, L Dana; Pessin, Michael S

    2004-09-01

    Among 407 New England Medical Center Posterior Circulation registry patients, 59% had strokes without transient ischemic attacks (TIAs), 24% had TIAs then strokes, and 16% had only TIAs. Embolism was the commonest stroke mechanism (40% of patients including 24% cardiac origin, 14% intraarterial, 2% cardiac and arterial sources). In 32% large artery occlusive lesions caused hemodynamic brain ischemia. Infarcts most often included the distal posterior circulation territory (rostral brainstem, superior cerebellum and occipital and temporal lobes); the proximal (medulla and posterior inferior cerebellum) and middle (pons and anterior inferior cerebellum) territories were equally involved. Severe occlusive lesions (>50% stenosis) involved more than one large artery in 148 patients; 134 had one artery site involved unilaterally or bilaterally. The commonest occlusive sites were: extracranial vertebral artery (52 patients, 15 bilateral) intracranial vertebral artery (40 patients, 12 bilateral), basilar artery (46 patients). Intraarterial embolism was the commonest mechanism of brain infarction in patients with vertebral artery occlusive disease. Thirty-day mortality was 3.6%. Embolic mechanism, distal territory location, and basilar artery occlusive disease carried the poorest prognosis. The best outcome was in patients who had multiple arterial occlusive sites; they had position-sensitive TIAs during months to years.

  14. Numerical simulation of a natural circulation loop

    Energy Technology Data Exchange (ETDEWEB)

    Verissimo, Gabriel L.; Moreira, Maria de Lourdes; Faccini, Jose Luiz H., E-mail: gabrielverissimo@poli.ufrj.b, E-mail: malu@ien.gov.b, E-mail: faccini@ien.gov.b [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2011-07-01

    This work presents a numerical simulation of a natural circulation loop using computational fluid dynamics. The simulated loop is an experimental model in a reduced scale of 1:10 of a passive heat removal system typical of advanced PWR reactors. The loop is composed of a heating vessel containing 52 electric heaters, a vertical shell-tube heat exchanger and a column of expansion. The working fluid is distilled water. Initially it was created a tridimensional geometric model of the loop components. After that, it was generated a tridimensional mesh of finite elements in order to calculate the variables of the problem. The boundaries of the numerical simulation were the power of the electric resistances and the cooling flow in the secondary side of the heat exchanger. The initial conditions were the temperature, the pressure and the fluid velocity at the time just before the power has been switched on. The results of this simulation were compared with the experimental data, in terms of the evolution of the temperatures in different locations of the loop, and of the average natural circulation flow as a function of time for a given power. (author)

  15. Circulating Tumor Cells Measurements in Hepatocellular Carcinoma

    Directory of Open Access Journals (Sweden)

    Franck Chiappini

    2012-01-01

    Full Text Available Liver cancer is the fifth most common cancer in men and the seventh in women. During the past 20 years, the incidence of HCC has tripled while the 5-year survival rate has remained below 12%. The presence of circulating tumor cells (CTC reflects the aggressiveness nature of a tumor. Many attempts have been made to develop assays that reliably detect and enumerate the CTC during the development of the HCC. In this case, the challenges are (1 there are few markers specific to the HCC (tumor cells versus nontumor cells and (2 they can be used to quantify the number of CTC in the bloodstream. Another technical challenge consists of finding few CTC mixed with million leukocytes and billion erythrocytes. CTC detection and identification can be used to estimate prognosis and may serve as an early marker to assess antitumor activity of treatment. CTC can also be used to predict progression-free survival and overall survival. CTC are an interesting source of biological information in order to understand dissemination, drug resistance, and treatment-induced cell death. Our aim is to review and analyze the different new methods existing to detect, enumerate, and characterize the CTC in the peripheral circulation of patients with HCC.

  16. Anomalous circulation patterns in association with two types of daily precipitation extremes over southeastern China during boreal summer

    Science.gov (United States)

    Li, Minggang; Guan, Zhaoyong; Jin, Dachao; Han, Jie; Zhang, Qian

    2016-04-01

    Based on the daily rainfall data from China Meteorological Administration, the tropical cyclone (TC) best track data from Japan Meteorological Agency, and the NCEP-NCAR reanalysis data from NOAA, regional mean daily precipitation extreme (RDPE) events over southeastern China (specifically, the Fujian-Jiangxi region (FJR)) and the associated circulation anomalies are investigated. For the summers of 1979-2011, a total of 105 RDPE events are identified, among which 35 are TC-influenced (TCIn-RDPE) and 70 are TC-free events (TCFr-RDPE). Distinct differences between these two types of RDPEs are found in both their statistical features and the related circulation patterns. TCFr-RDPEs usually occur in June, while TCIn-RDPEs mainly take place during July-August. When TCFr-RDPEs happen, a center of the anomalous cyclonic circulation is observed over the FJR, with an anomalous anticyclonic circulation to the south of this region. The warm/moist air flows from the South China Sea (SCS) and western Pacific meet with colder air from the north, forming a narrow convergent belt of water vapor over the FJR. Simultaneously, positive diabatic forcing anomalies are observed over the FJR, whereas negative anomalies appear over both its south and north sides, facilitating the formation and maintenance of the cyclonic circulation anomaly, as well as the upward motion of the atmosphere, over the FJR. When TCIn-RDPEs occur, southeastern China is dominated by a TC-related stronger anomalous cyclonic circulation. An anomalous anticyclonic circulation in the mid and high latitudes north of the FJR exists in the mid and upper troposphere, opposite to the situation during TCFr-RDPE events. Abundant warm/wet air is carried into the FJR from both the Indian Ocean and the SCS, leading to a large amount of latent heat release over the FJR and inducing strong ascending motion there. Furthermore, large differences are also found in the manifestation of Rossby wave energy propagation between these

  17. Anomalous Circulation Patterns in Association with Two Types of Daily Precipitation Extremes over Southeastern China during Boreal Summer

    Institute of Scientific and Technical Information of China (English)

    李明刚; 管亮勇; 金大超; 韩洁; 张茜

    2016-01-01

    Based on the daily rainfall data from China Meteorological Administration, the tropical cyclone (TC) best track data from Japan Meteorological Agency, and the NCEP-NCAR reanalysis data from NOAA, regional mean daily precipitation extreme (RDPE) events over southeastern China (specifically, the Fujian–Jiangxi region (FJR)) and the associated circulation anomalies are investigated. For the summers of 1979–2011, a total of 105 RDPE events are identified, among which 35 are TC-influenced (TCIn-RDPE) and 70 are TC-free events (TCFr-RDPE). Distinct differences between these two types of RDPEs are found in both their statistical features and the related circulation patterns. TCFr-RDPEs usually occur in June, while TCIn-RDPEs mainly take place during July–August. When TCFr-RDPEs happen, a center of the anomalous cyclonic circulation is observed over the FJR, with an anomalous anticyclonic circulation to the south of this region. The warm/moist air flows from the South China Sea (SCS) and western Pacific meet with colder air from the north, forming a narrow convergent belt of water vapor over the FJR. Simultaneously, positive diabatic forcing anomalies are observed over the FJR, whereas negative anomalies appear over both its south and north sides, facilitating the formation and maintenance of the cyclonic circulation anomaly, as well as the upward motion of the atmosphere, over the FJR. When TCIn-RDPEs occur, southeastern China is dominated by a TC-related stronger anomalous cyclonic circulation. An anomalous anticyclonic circulation in the mid and high latitudes north of the FJR exists in the mid and upper troposphere, opposite to the situation during TCFr-RDPE events. Abundant warm/wet air is carried into the FJR from both the Indian Ocean and the SCS, leading to a large amount of latent heat release over the FJR and inducing strong ascending motion there. Furthermore, large differences are also found in the manifestation of Rossby wave energy propagation between

  18. Novel solar air Heater for high temperatures; Novedoso Calentador solar de aire para altas temperaturas

    Energy Technology Data Exchange (ETDEWEB)

    Rincon, E. A.; Duran, M. D.; Lentz, A. E.

    2008-07-01

    A novel solar air heater that allows to reach temperatures of the order of 100 degree centigrade with thermal efficiencies superior to 50% due to a solar concentrator and the reduction of thermal losses from the air when circulating between the absorber and mirrors of section of circular arc, well isolated of the outside surrounding. The receiver consists of a concentrator with wedges of plastic transparency that make the function of lenses. The light refracted by the wedges enters to a series of concentrators PC type truncated optimally so that the space among them allows the positioning of the absorber, who are covered metallic segments with selective film. Its excellent performance makes ideals applications as Sauna bath, the drying at high temperature, and systems for conditioning of air. (Author)

  19. Radiation and atmospheric circulation controls on carbonyl sulfide concentrations in the marine boundary layer

    Science.gov (United States)

    Berkelhammer, M.; Steen-Larsen, H. C.; Cosgrove, A.; Peters, A. J.; Johnson, R.; Hayden, M.; Montzka, S. A.

    2016-11-01

    A potential closure of the global carbonyl sulfide (COS or OCS) budget has recently been attained through a combination of remote sensing, modeling, and extended surface measurements. However, significant uncertainties in the spatial and temporal dynamics of the marine flux still persist. In order to isolate the terrestrial photosynthetic component of the global atmospheric OCS budget, tighter constraints on the marine flux are needed. We present 6 months of nearly continuous in situ OCS concentrations from the North Atlantic during the fall and winter of 2014-2015 using a combination of research vessel and fixed tower measurements. The data are characterized by synoptic-scale ˜100 pmol mol-1 variations in marine boundary layer air during transitions from subtropical to midlatitude source regions. The synoptic OCS variability is shown here to be a linear function of the radiation history along an air parcel's trajectory with no apparent sensitivity to the chlorophyll concentration of the surface waters that the air mass interacted with. This latter observation contradicts expectations and suggests a simple radiation limitation for the combined direct and indirect marine OCS emissions. Because the concentration of OCS in the marine boundary layer is so strongly influenced by an air parcel's history, marine and atmospheric concentrations would rarely be near equilibrium and thus even if marine production rates are held constant at a given location, the ocean-atmosphere flux would be sensitive to changes in atmospheric circulation alone. We hypothesize that changes in atmospheric circulation including latitudinal shifts in the storm tracks could affect the marine flux through this effect.

  20. Circulation types classification for hourly precipitation events in Lublin (East Poland)

    Science.gov (United States)

    Bartoszek, Krzysztof; Skiba, Dominika

    2016-04-01

    The paper presents an objective classification of circulation types for East-Central Europe with application to hourly precipitation events in Lublin (East Poland) from May to September. The development of the classification utilized sub-daily sea-level pressure values (at the main standard synoptic hours, i.e. 00, 06, 12 and 18 UTC). Sea-level pressure values and physical quantities (resultant flow direction and total shear vorticity) defined 27 circulation types: a) eight each of the directional cyclonic, transitional, and anticyclonic circulation types, and b) one each of the non-directional cyclonic, anticyclonic, and undefined types. In the years 1961-2010, the highest mean precipitation amount in the study area was recorded for cyclonic non-directional type C, followed by cyclonic types with air flow from the western and northern sectors. Type C was also distinguished by the highest number of precipitation events with high intensity irrespective of their duration, i.e. short-term, medium-term, and long-term precipitation events. Moreover, in the class of cyclonic types, precipitation events were considerably longer than in anticyclonic and transitional types. On the other hand, for anticyclonic types, precipitation with high intensity was recorded much more rarely, particularly in the case of advection from the southern sector.

  1. Microsurgical anatomy of the posterior circulation

    Directory of Open Access Journals (Sweden)

    Pai Balaji

    2007-01-01

    Full Text Available Context: The microsurgical anatomy of the posterior circulation is very complex and variable. Surgical approaches to this area are considered risky due to the presence of the various important blood vessels and neural structures. Aims: To document the microsurgical anatomy of the posterior circulation along with variations in the Indian population. Materials and Methods: The authors studied 25 cadaveric brain specimens. Microsurgical dissection was carried out from the vertebral arteries to the basilar artery and its branches, the basilar artery bifurcation, posterior cerebral artery and its various branches. Measurements of the outer diameters of the vertebral artery, basilar artery and posterior cerebral artery and their lengths were taken. Results: The mean diameter of the vertebral artery was 3.4 mm on the left and 2.9 mm on the right. The diameter of the basilar artery varied from 3-7 mm (mean of 4.3 mm. The length varied from 24-35 mm (mean of 24.9 mm. The basilar artery gave off paramedian and circumferential perforating arteries. The origin of the anterior inferior cerebellar artery (AICA varied from 0-21 mm (mean 10.0 mm from the vertebrobasilar junction. The diameter of the AICA varied from being hypoplastic i.e., < 0.5 mm to 2 mm (mean 1.0 mm. The superior cerebellar artery (SCA arises very close to the basilar bifurcation, in our series (1-3 mm from the basilar artery bifurcation. The diameter of the SCA varied from 0.5-2.5 mm on both sides. The posterior cerebral artery (PCA is divided into four segments. The PCA gave rise to perforators (thalamoperforators, thalamogeniculate arteries, circumflex arteries and peduncular arteries, medial posterior choroidal artery, lateral posterior choroidal artery and cortical branches. In 39 specimens the P1 segment was found to be larger than the posterior communicating artery, in six specimens it was found to be equal to the diameter of the posterior communicating artery and in five specimens it

  2. Interannual variability of South American monsoon circulation

    Science.gov (United States)

    Alonso Gan, Manoel; Rafaele Araújo Lima, Jeane

    2016-04-01

    The South America Monsoon System (SAMS) is responsible for influencing the atmospheric circulation and precipitation over most of tropical South America (SA) during the summer season. Studies for aiming to understand the temporal variability of this system have great value to the scientific community, because the processes that control the monsoon climate are not totally clear. Thus, the main objective of this research is to investigate the possible large-scale climatic factors and the remote interaction mechanisms, which may be associated with summer season interannual variability focusing on identifying the main differences between dry and wet extremes rainy season in the South-eastern Amazon Basin (SAB), Central-West (WC) and Southeast (SE) of Brazil, which are areas influenced by the summer monsoon regime. For such analyzes, Pearson correlations, quantile method and composite analysis were used during the period from 1979 to 2014. The correlation between precipitation anomaly in SAB and the sea surface temperature anomaly (SSTA) and wind at 850hPa and 300hPa indicate El Niño-Southern Oscillation (ENSO) influence. Precipitation anomalies in WC did not show significant correlation with SSTA. However, a pattern similar to ENSO Modoki type was observed in the composite analysis. At 850 hPa, the presence of an anomalous cyclonic (anticyclonic) circulation was observed over the central region of SA during wet (dry) summers seasons. Over SE region of Brazil, a dipole SSTA pattern over the South Atlantic was identified, as well the presence of anomalous circulations with an equivalent barotropic structure over these SSTA areas. This pattern is more evident in case of dry summer on the SE. At 300 hPa, the wave train between 30°S-60°S was observed presenting a feature curvature from 120°W reaching SA, similar to the Pacific-South American pattern (PSA). Analysis of the summer interannual variability indicated the manifestation of wet summers more frequently than dry

  3. Solar collecting characteristics of regenerative solar air collector; Chikunetsushiki kuki shunetsuki no shunetsu tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, H.; Takano, S.; Kamitaira, T. [Hachinohe Institute of Technology, Aomori (Japan)

    1997-11-25

    In order to develop a solar drying equipment for agricultural and marine products, a regenerative solar air collector was fabricated on a trial basis, which uses round stones as a heat storing material. Its heat collecting characteristics were discussed. The air heat collector was installed on a roof of the Hachinohe Engineering University facing due south. The inside of the air heat collector is lined with heat insulating material with a thickness of 30 mm, and black-painted round stones were laid as an heat insulating material on the floor and the north face. The collector is of a natural air circulating system in which outside air enters from an entrance open to atmosphere, and warmed air exits from upper exit. A selectively absorbing face plaque for accelerating the natural circulation was suspended on the upper part of the north face of the collector. An experiment was performed also on a case in which air is forcibly circulated by fan from the air exit hole. In the natural circulation system, high heat collecting efficiency is shown in the forenoon. However, heat loss increases as temperature in the equipment rises, and heat stored in the round stones during daytime was dissipated completely in the afternoon to night. In the case of the forced circulation system, heat collecting efficiency as high as about 90% was shown in sunny days. This is thought because of heat storage buffering action due to storage of heat in and its dissipation from the round stones, and because of suppression of heat dissipation from the glass surface. 1 ref., 9 figs.

  4. Two Types of Designs for On-Line Circulation Systems

    Directory of Open Access Journals (Sweden)

    Rob McGee

    1972-09-01

    Full Text Available On-line circulation systems divide into two types. One type contains records only for charged or otherwise absent items. The other contains a file of records for all titles or volumes in the library collection, regardless of their circulation status. This paper traces differences between the two types, examining different kinds of files and terminals, transaction evidence, the quality of bibliographic data, querying, and the possibility of functions outside circulation. Aspects of both operational and potential systems are considered.

  5. Stability of Thermohaline circulation with respect to fresh water release

    OpenAIRE

    Patwardhan, Ajay; Tewary, Vivek

    2008-01-01

    The relatively warm climate found in the North- Western Europe is due to the gulf stream that circulates warm saline water from southern latitudes to Europe. In North Atlantic ocean the stream gives out a large amount of heat, cools down and sinks to the bottom to complete the Thermohaline circulation. There is considerable debate on the stability of the stream to inputs of fresh water from the melting ice in Greenland and Arctic. The circulation, being switched off, will have massive impact ...

  6. REACH. Air Conditioning Units.

    Science.gov (United States)

    Garrison, Joe; And Others

    As a part of the REACH (Refrigeration, Electro-Mechanical, Air-Conditioning, Heating) electromechanical cluster, this student manual contains individualized instructional units in the area of air conditioning. The instructional units focus on air conditioning fundamentals, window air conditioning, system and installation, troubleshooting and…

  7. Statistical air quality mapping

    NARCIS (Netherlands)

    Kassteele, van de J.

    2006-01-01

    This thesis handles statistical mapping of air quality data. Policy makers require more and more detailed air quality information to take measures to improve air quality. Besides, researchers need detailed air quality information to assess health effects. Accurate and spatially highly resolved maps

  8. A review of scientifc linkages and interactions between climate change and air quality, with implications for air quality management in South Africa

    Directory of Open Access Journals (Sweden)

    Tirusha Thambiran

    2010-04-01

    Full Text Available In recent years there has been considerable advancement in our scientifc understanding of the linkages and interactions between climate change and air quality. A warmer, evolving climate is likely to have severe consequences for air quality due to impacts on pollution sources and meteorology. Climate-induced changes to sources of tropospheric ozone precursor gases and to atmospheric circulation are likely to lead to changes in both the concentration and dispersion of near-surface ozone that could act to offset improvements in air quality. The control of air pollutants through air quality management is also likely to impact on climate change, with reductions in ozone, particulate matter and sulphur dioxide being of particular interest. The improved understanding of the relationship between air quality and climate change provides a scientific basis for policy interventions. After a review of the scientific linkages, the potential to include climate change considerations in air quality management planning processes in South Africa was examined.

  9. BIM-enabled Conceptual Modelling and Representation of Building Circulation

    Directory of Open Access Journals (Sweden)

    Jin Kook Lee

    2014-08-01

    Full Text Available This paper describes how a building information modelling (BIM-based approach for building circulation enables us to change the process of building design in terms of its computational representation and processes, focusing on the conceptual modelling and representation of circulation within buildings. BIM has been designed for use by several BIM authoring tools, in particular with the widely known interoperable industry foundation classes (IFCs, which follow an object-oriented data modelling methodology. Advances in BIM authoring tools, using space objects and their relations defined in an IFC’s schema, have made it possible to model, visualize and analyse circulation within buildings prior to their construction. Agent-based circulation has long been an interdisciplinary topic of research across several areas, including design computing, computer science, architectural morphology, human behaviour and environmental psychology. Such conventional approaches to building circulation are centred on navigational knowledge about built environments, and represent specific circulation paths and regulations. This paper, however, places emphasis on the use of ‘space objects’ in BIM-enabled design processes rather than on circulation agents, the latter of which are not defined in the IFCs’ schemas. By introducing and reviewing some associated research and projects, this paper also surveys how such a circulation representation is applicable to the analysis of building circulation-related rules.

  10. [Harvey and his theory of circulation].

    Science.gov (United States)

    Wolters, Frank J

    2013-01-01

    In 1628 the English physician William Harvey (1578-1657) published his revolutionary theory that blood circulates through the body driven by the heart. This challenged the long-standing teachings of Hippocrates and Galen concerning 4 different bodily fluids or 'humours' that flowed through separate arterial and venous vascular systems. Harvey gained considerable influence in society as a member of the prestigious Royal College of Physicians in London and as personal physician to King James I and King Charles I. He strove for a more empirical foundation of medicine by means of anatomic demonstrations and vivisections. Despite enduring considerable criticism he managed to disseminate his ideas around the influential universities of Europe in the course of his lifetime. However, consequent changes in practice would not be brought about until decades after Harvey's death, when Galenist treatments such as blood-letting were gradually abandoned.

  11. Circulating Biomarkers for Duchenne Muscular Dystrophy

    Science.gov (United States)

    Aartsma-Rus, Annemieke; Spitali, Pietro

    2015-01-01

    Abstract Duchenne muscular dystrophy is the most common form of muscular dystrophy. Genetic and biochemical research over the years has characterized the cause, pathophysiology and development of the disease providing several potential therapeutic targets and/or biomarkers. High throughput – omic technologies have provided a comprehensive understanding of the changes occurring in dystrophic muscles. Murine and canine animal models have been a valuable source to profile muscles and body fluids, thus providing candidate biomarkers that can be evaluated in patients. This review will illustrate known circulating biomarkers that could track disease progression and response to therapy in patients affected by Duchenne muscular dystrophy. We present an overview of the transcriptomic, proteomic, metabolomics and lipidomic biomarkers described in literature. We show how studies in muscle tissue have led to the identification of serum and urine biomarkers and we highlight the importance of evaluating biomarkers as possible surrogate endpoints to facilitate regulatory processes for new medicinal products. PMID:27858763

  12. Bordetella pertussis: why is it still circulating?

    Science.gov (United States)

    Guiso, Nicole

    2014-01-01

    Bordetella pertussis is the causal agent of whooping cough, a highly contagious respiratory disease that is life-threatening in infants under the age of three months and may also be very severe in pregnant women and seniors. This disease can be prevented by vaccination but it remains a public health problem in many developed and developing countries.(1) So, why is B. pertussis still circulating? We need to consider several aspects of this vaccine-preventable disease when answering this question: (i) the history of the disease and the historical context in which the vaccine was developed; (ii) the type of vaccine used; (iii) the vaccination strategy and coverage; (iv) the disease surveillance after the introduction of generalized vaccination and (v) the surveillance for the causal agent of the disease.

  13. Circulation and Dissipation on Hot Jupiters

    CERN Document Server

    Li, Jason

    2010-01-01

    Many global circulation models predict supersonic zonal winds and large vertical shears in the atmospheres of short-period jovian exoplanets. Using linear analysis and nonlinear local simulations, we investigate hydrodynamic dissipation mechanisms to balance the thermal acceleration of these winds. The adiabatic Richardson criterion remains a good guide to linear stability, although thermal diffusion allows some modes to violate it at very long wavelengths and very low growth rates. Nonlinearly, wind speeds saturate at Mach numbers $\\approx 2$ and Richardson numbers $\\lesssim 1/4$ for a broad range of plausible diffusivities and forcing strengths. Turbulence and vertical mixing, though accompanied by weak shocks, dominate the dissipation, which appears to be the outcome of a recurrent Kelvin-Helmholtz instability. An explicit shear viscosity, as well as thermal diffusivity, is added to ZEUS to capture dissipation outside of shocks. The wind speed is not monotonic nor single valued for shear viscosities larger...

  14. Circulating amounts of osteoprotegerin and RANK ligand

    DEFF Research Database (Denmark)

    Abrahamsen, Bo; Hjelmborg, Jacob Vb; Kostenuik, Paul;

    2005-01-01

    was 1.04 +/- 0.11 g/cm2. Serum levels of OPG and RANKL were measured by ELISA (Biomedica, Vienna, Austria). Thisregister covers twins born in Denmark since 1870. Heritability and environmental influence was assessed using a maximum-likelihood model for genetic pleiotropy. RESULTS: RANKL levels showed...... only a weak relation to BMD in healthy women. Phenotype correlations indicate that the genes that contribute to twin similarity for BMD are not genes regulating serum levels of RANKL or OPG. The weak correlation with BMDappears to consist in shared environmental factors....... and cytokines. The influence of genetic factors on circulating amounts of OPG and RANKL is not known. BMD has been demonstrated to have a high heritability and there is evidence also that bone turnover and bone loss rates are controlled at least in part by genetic factors. OBJECTIVE: Assessing the genetic...

  15. Circulating Tumor Cells in Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Brian [Institute of Urology, University of Southern California, 1441 Eastlake Avenue, Suite 7416, Los Angeles, CA 90033 (United States); Rochefort, Holly [Department of Surgery, University of Southern California, 1520 San Pablo Street, HCT 4300, Los Angeles, CA 90033 (United States); Goldkorn, Amir, E-mail: agoldkor@usc.edu [Department of Internal Medicine and Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1441 Eastlake Avenue, Suite 3440, Los Angeles, CA 90033 (United States)

    2013-12-04

    Circulating tumor cells (CTCs) can provide a non-invasive, repeatable snapshot of an individual patient’s tumor. In prostate cancer, CTC enumeration has been extensively studied and validated as a prognostic tool and has received FDA clearance for use in monitoring advanced disease. More recently, CTC analysis has been shifting from enumeration to more sophisticated molecular characterization of captured cells, which serve as a “liquid biopsy” of the tumor, reflecting molecular changes in an individual’s malignancy over time. Here we will review the main CTC studies in advanced and localized prostate cancer, highlighting the important gains as well as the challenges posed by various approaches, and their implications for advancing prostate cancer management.

  16. Boiling Heat Transfer in Circulating Fluidized Beds

    Institute of Scientific and Technical Information of China (English)

    张利斌; 李修伦

    2001-01-01

    A model is proposed to predict boiling heat transfer coefficient in a three-phase circulating fluidized bed (CFB), which is a new type of evaporation boiling means for enhancing heat transfer and preventing fouling. To verify the model, experiments are conducted in a stainless steel column with 39 mm ID and 2.0 m height, in which the heat transfer coefficient is measured for different superficial velocities, steam pressures, particle concentrations and materials of particle. As the steam pressure and particle concentrations increase, the heat transfer coefficient in the bed increases. The heat transfer coefficient increases with the liquid velocity but it exhibits a local minimum.The heat transfer coefficient is correlated with cluster renewed model and two-mechanism method. The prediction of the model is in good agreement with experimental data.

  17. Boiling Heat Transfer in Circulating Fluidized Beds

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A model is proposed to predict boiling heat transfer coefficient in a three-phase circulating fluidized bed (CFB), which is a new type of evaporation boiling means for enhancing heat transfer and preventing fouling. To verify the model, experiments are conducted in a stainless steel column with 39mm ID and 2.0m height, in which the heat transfer coefficient is measured for different superficial velocities, steam pressures, particle concentrations and materials of particle. As the steam pressure and particle concentrations increase, the heat transfer coefficient in the bed increases. The heat transfer coefficient increases with the liquid velocity but it exhibits a local minimum. The heat transfer coefficient is correlated with cluster renewed model and two-mechanism method. The prediction of the model is in good agreement with experimental data.

  18. Circulating Tumor Cells in Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Brian Hu

    2013-12-01

    Full Text Available Circulating tumor cells (CTCs can provide a non-invasive, repeatable snapshot of an individual patient’s tumor. In prostate cancer, CTC enumeration has been extensively studied and validated as a prognostic tool and has received FDA clearance for use in monitoring advanced disease. More recently, CTC analysis has been shifting from enumeration to more sophisticated molecular characterization of captured cells, which serve as a “liquid biopsy” of the tumor, reflecting molecular changes in an individual’s malignancy over time. Here we will review the main CTC studies in advanced and localized prostate cancer, highlighting the important gains as well as the challenges posed by various approaches, and their implications for advancing prostate cancer management.

  19. Circulating tumor cells: highlight on practical implications.

    Science.gov (United States)

    Gazzaniga, Paola; Raimondi, Cristina; Gradilone, Angela; Naso, Giuseppe; Cortesi, Enrico; Frati, Luigi

    2012-02-01

    Circulating tumor cells (CTCs) are cells of presumed epithelial origin, whose prognostic and predictive value in metastatic cancer patients has recently been demonstrated. To date, the count of CTCs through the CellSearch® system represents a valid approach for monitoring disease status in patients with metastatic colorectal, breast, and prostate cancer; in these cancer types, a rise in the CTC count at any time during treatment predicts a poor outcome. Nevertheless, the clinical utility of monitoring CTC counts remains controversial, and what to do when CTC counts rise during therapy still remains an unanswered question. In this report, we suggest how to integrate CTC counts with their molecular characterization to better translate biologic information obtained on CTCs into daily clinical practice.

  20. Subsurface Meridional Circulation in the Active Belts

    CERN Document Server

    Hernandez, I Gonzalez; Hill, F; Howe, R; Komm, R

    2008-01-01

    Temporal variations of the subsurface meridional flow with the solar cycle have been reported by several authors. The measurements are typically averaged over periods of time during which surface magnetic activity existed in the regions were the velocities are calculated. The present work examines the possible contamination of these measurements due to the extra velocity fields associated with active regions plus the uncertainties in the data obtained where strong magnetic fields are present. We perform a systematic analysis of more than five years of GONG data and compare meridional flows obtained by ring-diagram analysis before and after removing the areas of strong magnetic field. The overall trend of increased amplitude of the meridional flow towards solar minimum remains after removal of large areas associated with surface activity. We also find residual circulation toward the active belts that persist even after the removal of the surface magnetic activity, suggesting the existence of a global pattern o...

  1. Circulating Tumor Cells, Enumeration and Beyond

    Directory of Open Access Journals (Sweden)

    Jian-Mei Hou

    2010-06-01

    Full Text Available The detection and enumeration of circulating tumor cells (CTCs has shown significant clinical utility with respect to prognosis in breast, colorectal and prostate cancers. Emerging studies show that CTCs can provide pharmacodynamic information to aid therapy decision making. CTCs as a ‘virtual and real-time biopsy’ have clear potential to facilitate exploration of tumor biology, and in particular, the process of metastasis. The challenge of profiling CTC molecular characteristics and generating CTC signatures using current technologies is that they enrich rather than purify CTCs from whole blood; we face the problem of looking for the proverbial ‘needle in the haystack’. This review summarizes the current methods for CTC detection and enumeration, focuses on molecular characterization of CTCs, unveils some aspects of CTC heterogeneity, describes attempts to purify CTCs and scans the horizon for approaches leading to comprehensive dissection of CTC biology.

  2. Meridional circulation in the Sun and stars

    CERN Document Server

    Kitchatinov, L L

    2016-01-01

    Mean-field hydrodynamics advanced to clear explanations for the origin and properties of the global meridional flow in stellar convection zones. Qualitative arguments and analysis of basic equations both show that the meridional circulation is driven by non-conservative centrifugal and buoyancy forces and results from a slight disbalance between these two drivers. The deviations from the thermal wind balance are relatively large near the boundaries of convection zones. Accordingly, the meridional flow attains its largest velocities in the boundary layers and decreases inside the convection zone. This picture, however, is neither supported nor dismissed by the conflicting results of recent helioseismic soundings or 3D numerical experiments. The relevant physics of the differential temperature and its possible relation to the solar oblateness are briefly discussed.

  3. Circulating tumor cells: utopia or reality?

    Science.gov (United States)

    Conteduca, Vincenza; Zamarchi, Rita; Rossi, Elisabetta; Condelli, Valentina; Troiani, Laura; Aieta, Michele

    2013-09-01

    Circulating tumor cells (CTCs) could be considered a sign of tumor aggressiveness, but highly sensitive and specific methods of CTC detection are necessary owing to the rarity and heterogeneity of CTCs in peripheral blood. This review summarizes recent studies on tumor biology, with particular attention to the metastatic cascade, and the molecular characterization and clinical significance of CTCs. Recent technological approaches to enrich and detect these cells and challenges of CTCs for individualized cancer treatment are also discussed. This review also provides an insight into the positive and negative features of the future potential applications of CTC detection, which sometimes remains still a 'utopia', but its actual utility remains among the fastest growing research fields in oncology.

  4. Fragment Length of Circulating Tumor DNA.

    Directory of Open Access Journals (Sweden)

    Hunter R Underhill

    2016-07-01

    Full Text Available Malignant tumors shed DNA into the circulation. The transient half-life of circulating tumor DNA (ctDNA may afford the opportunity to diagnose, monitor recurrence, and evaluate response to therapy solely through a non-invasive blood draw. However, detecting ctDNA against the normally occurring background of cell-free DNA derived from healthy cells has proven challenging, particularly in non-metastatic solid tumors. In this study, distinct differences in fragment length size between ctDNAs and normal cell-free DNA are defined. Human ctDNA in rat plasma derived from human glioblastoma multiforme stem-like cells in the rat brain and human hepatocellular carcinoma in the rat flank were found to have a shorter principal fragment length than the background rat cell-free DNA (134-144 bp vs. 167 bp, respectively. Subsequently, a similar shift in the fragment length of ctDNA in humans with melanoma and lung cancer was identified compared to healthy controls. Comparison of fragment lengths from cell-free DNA between a melanoma patient and healthy controls found that the BRAF V600E mutant allele occurred more commonly at a shorter fragment length than the fragment length of the wild-type allele (132-145 bp vs. 165 bp, respectively. Moreover, size-selecting for shorter cell-free DNA fragment lengths substantially increased the EGFR T790M mutant allele frequency in human lung cancer. These findings provide compelling evidence that experimental or bioinformatic isolation of a specific subset of fragment lengths from cell-free DNA may improve detection of ctDNA.

  5. Fragment Length of Circulating Tumor DNA.

    Science.gov (United States)

    Underhill, Hunter R; Kitzman, Jacob O; Hellwig, Sabine; Welker, Noah C; Daza, Riza; Baker, Daniel N; Gligorich, Keith M; Rostomily, Robert C; Bronner, Mary P; Shendure, Jay

    2016-07-01

    Malignant tumors shed DNA into the circulation. The transient half-life of circulating tumor DNA (ctDNA) may afford the opportunity to diagnose, monitor recurrence, and evaluate response to therapy solely through a non-invasive blood draw. However, detecting ctDNA against the normally occurring background of cell-free DNA derived from healthy cells has proven challenging, particularly in non-metastatic solid tumors. In this study, distinct differences in fragment length size between ctDNAs and normal cell-free DNA are defined. Human ctDNA in rat plasma derived from human glioblastoma multiforme stem-like cells in the rat brain and human hepatocellular carcinoma in the rat flank were found to have a shorter principal fragment length than the background rat cell-free DNA (134-144 bp vs. 167 bp, respectively). Subsequently, a similar shift in the fragment length of ctDNA in humans with melanoma and lung cancer was identified compared to healthy controls. Comparison of fragment lengths from cell-free DNA between a melanoma patient and healthy controls found that the BRAF V600E mutant allele occurred more commonly at a shorter fragment length than the fragment length of the wild-type allele (132-145 bp vs. 165 bp, respectively). Moreover, size-selecting for shorter cell-free DNA fragment lengths substantially increased the EGFR T790M mutant allele frequency in human lung cancer. These findings provide compelling evidence that experimental or bioinformatic isolation of a specific subset of fragment lengths from cell-free DNA may improve detection of ctDNA.

  6. Circulating Biomarker Panels in Alzheimer's Disease.

    Science.gov (United States)

    Zafari, Sachli; Backes, Christina; Meese, Eckart; Keller, Andreas

    2015-01-01

    The early diagnosis of diseases frequently represents an important unmet clinical need supporting in-time treatment of pathologies. This also applies to neurodegenerative diseases such as Alzheimer's disease (AD), the most common form of dementia, estimated to affect millions of individuals worldwide. The respective diagnostic and prognostic markers, especially for the preclinical stages of AD, are expected to improve patients' outcome significantly. In the last decades, many approaches to detecting AD have been developed, including markers to discover changes in amyloid-β levels [from cerebrospinal fluid (CSF) or using positron emission tomography] or other brain imaging technologies such as structural magnetic resonance imaging (MRI), functional-connectivity MRI or task-related functional MRI. A major challenge is the detection of AD using minimally or even noninvasive biomarkers from body fluids such as plasma or serum. Circulating biomarker candidates based on mRNAs or proteins measured from blood cells, plasma or serum have been proposed for various pathologies including AD. As for other diseases, there is a tendency to use marker signatures obtained by high-throughput approaches, which allow the generation of profiles of hundreds to thousands of biomarkers simultaneously [microarrays, mass spectrometry or next-generation sequencing (NGS)]. Beyond mRNAs and proteins, recent approaches have measured small noncoding RNA (so-called microRNA) profiles in AD patients' blood samples using NGS or array-based technologies. Generally, the development of marker panels is in its early stages and requires further, substantial clinical validation. In this review, we provide an overview of different circulating AD biomarkers, starting with a brief summary of CSF markers and focusing on novel biomarker signatures such as small noncoding RNA profiles.

  7. A new torsion control mechanism induced by blood circulation in dragonfly wings.

    Science.gov (United States)

    Hou, Dan; Yin, Yajun; Zhong, Zheng; Zhao, Hongxiao

    2015-02-06

    A new mechanism to generate the torque of flapping dragonfly wings is disclosed in this paper. The concept is inspired by blood circulation in insect wings. The blood flowing in veins induces Coriolis forces in the flapping wings. The Coriolis forces acting on veins are of opposite directions when blood flows in and out. The opposite Coriolis forces generate torsional moment to the wing, especially in the leading-edge part. To estimate the time-varying torque induced by the blood circulation, a simplified U-tube model is designed. A three-dimensional finite element model of the wing is developed to analyze the dynamic behaviors under this torque. The dragonfly wing is in favor of torsional deformation because the corrugated structure is of high flexural rigidity in the spanwise direction but is of low torsional rigidity in the chordwise direction. In both the downstroke and upstroke, the twist of the leading-edge part causes the sections to camber spontaneously. Such a kind of deformation is found to be of great importance to improve aerodynamic efficiency. In addition, it also compensates for the disadvantageous bending deformation caused by air pressure in flapping flight. These results are important for better understanding of the multifunctional structures of dragonfly wings and may give some inspiration to the bionics of flapping-wing micro air vehicles (FMAVs).

  8. Air movement and perceived air quality

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Kaczmarczyk, J.

    2012-01-01

    The impact of air movement on perceived air quality (PAQ) and sick building syndrome (SBS) symptoms was studied. In total, 124 human subjects participated in four series of experiments performed in climate chambers at different combinations of room air temperature (20, 23, 26 and 28 °C), relative...... and the humidity of the room air. At a low humidity level of 30% an increased velocity could compensate for the decrease in perceived air quality due to an elevated temperature ranging from 20 °C to 26 °C. In a room with 26 °C, increased air movement was also able to compensate for an increase in humidity from 30...

  9. Performance of the Helium Circulation System on a Commercialized MEG

    Science.gov (United States)

    T, Takeda; M, Okamoto; T, Miyazaki; K, Katagiri

    2012-12-01

    We report the performance of a helium circulation system (HCS) mounted on a MEG (Magnetoencephalography) at Nagoya University, Japan. This instrument is the first commercialized version of an HCS. The HCS collects warm helium gas at approximately 300 K and then cools it to approximately 40 K. The gas is returned to the neck tube of a Dewar of the MEG to keep it cold. It also collects helium gas in the region just above the liquid helium surface while it is still cold, re-liquefies the gas and returns it to the Dewar. A special transfer tube (TT) of approximately 3 m length was developed to allow for dual helium streams. This tube separates the HCS using a MEG to reduce magnetic noise. A refiner was incorporated to effectively collect contaminating gases by freezing them. The refiner was equipped with an electric heater to remove the frozen contaminants as gases into the air. A gas flow controller was also developed, which automatically controlled the heater and electric valves to clean up contamination. The developed TT exhibited a very low heat inflow of less than 0.1 W/m to the liquid helium, ensuring efficient operation. The insert tube diameter, which was 1.5 in. was reduced to a standard 0.5 in. size. This dimensional change enabled the HCS to mount onto any commercialized MEG without any modifications to the MEG. The HCS can increase liquid helium in the Dewar by at least 3 liters/Day using two GM cryocoolers (SRDK-415D, Sumitomo Heavy Industries, Ltd.). The noise levels were virtually the same as before this installation.

  10. Circulating Tumor Cells Versus Circulating Tumor DNA in Colorectal Cancer: Pros and Cons.

    Science.gov (United States)

    Tan, Carlyn Rose C; Zhou, Lanlan; El-Deiry, Wafik S

    2016-06-01

    Circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) are emerging noninvasive multifunctional biomarkers in liquid biopsy allowing for early diagnosis, accurate prognosis, therapeutic target selection, spatiotemporal monitoring of metastasis, as well as monitoring response and resistance to treatment. CTCs and ctDNA are released from different tumor types at different stages and contribute complementary information for clinical decision. Although big strides have been taken in technology development for detection, isolation and characterization of CTCs and sensitive and specific detection of ctDNA, CTC-, and ctDNA-based liquid biopsies may not be widely adopted for routine cancer patient care until the suitability, accuracy, and reliability of these tests are validated and more standardized protocols are corroborated in large, independent, prospectively designed trials. This review covers CTC- and ctDNA-related technologies and their application in colorectal cancer. The promise of CTC-and ctDNA-based liquid biopsies is envisioned.

  11. Correcting circulation biases in a lower-resolution global general circulation model with data assimilation

    Science.gov (United States)

    Canter, Martin; Barth, Alexander; Beckers, Jean-Marie

    2017-02-01

    In this study, we aim at developing a new method of bias correction using data assimilation. This method is based on the stochastic forcing of a model to correct bias by directly adding an additional source term into the model equations. This method is presented and tested first with a twin experiment on a fully controlled Lorenz '96 model. It is then applied to the lower-resolution global circulation NEMO-LIM2 model, with both a twin experiment and a real case experiment. Sea surface height observations are used to create a forcing to correct the poorly located and estimated currents. Validation is then performed throughout the use of other variables such as sea surface temperature and salinity. Results show that the method is able to consistently correct part of the model bias. The bias correction term is presented and is consistent with the limitations of the global circulation model causing bias on the oceanic currents.

  12. Correcting circulation biases in a lower-resolution global general circulation model with data assimilation

    Science.gov (United States)

    Canter, Martin; Barth, Alexander; Beckers, Jean-Marie

    2016-12-01

    In this study, we aim at developing a new method of bias correction using data assimilation. This method is based on the stochastic forcing of a model to correct bias by directly adding an additional source term into the model equations. This method is presented and tested first with a twin experiment on a fully controlled Lorenz '96 model. It is then applied to the lower-resolution global circulation NEMO-LIM2 model, with both a twin experiment and a real case experiment. Sea surface height observations are used to create a forcing to correct the poorly located and estimated currents. Validation is then performed throughout the use of other variables such as sea surface temperature and salinity. Results show that the method is able to consistently correct part of the model bias. The bias correction term is presented and is consistent with the limitations of the global circulation model causing bias on the oceanic currents.

  13. The thrombotic potential of circulating tumor microemboli: computational modeling of circulating tumor cell-induced coagulation

    OpenAIRE

    Phillips, Kevin G.; Lee, Angela M.; Tormoen, Garth W.; Rigg, Rachel A.; Kolatkar, Anand; Luttgen, Madelyn; Bethel, Kelly; Bazhenova, Lyudmila; Kuhn, Peter; Newton, Paul; McCarty, Owen J.T.

    2014-01-01

    Thrombotic events can herald the diagnosis of cancer, preceding any cancer-related clinical symptoms. Patients with cancer are at a 4- to 7-fold increased risk of suffering from venous thromboembolism (VTE), with ∼7,000 patients with lung cancer presenting from VTEs. However, the physical biology underlying cancer-associated VTE remains poorly understood. Several lines of evidence suggest that the shedding of tissue factor (TF)-positive circulating tumor cells (CTCs) and microparticles from p...

  14. Climatology of the HOPE-G global ocean general circulation model - Sea ice general circulation model

    Energy Technology Data Exchange (ETDEWEB)

    Legutke, S. [Deutsches Klimarechenzentrum (DKRZ), Hamburg (Germany); Maier-Reimer, E. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany)

    1999-12-01

    The HOPE-G global ocean general circulation model (OGCM) climatology, obtained in a long-term forced integration is described. HOPE-G is a primitive-equation z-level ocean model which contains a dynamic-thermodynamic sea-ice model. It is formulated on a 2.8 grid with increased resolution in low latitudes in order to better resolve equatorial dynamics. The vertical resolution is 20 layers. The purpose of the integration was both to investigate the models ability to reproduce the observed general circulation of the world ocean and to obtain an initial state for coupled atmosphere - ocean - sea-ice climate simulations. The model was driven with daily mean data of a 15-year integration of the atmosphere general circulation model ECHAM4, the atmospheric component in later coupled runs. Thereby, a maximum of the flux variability that is expected to appear in coupled simulations is included already in the ocean spin-up experiment described here. The model was run for more than 2000 years until a quasi-steady state was achieved. It reproduces the major current systems and the main features of the so-called conveyor belt circulation. The observed distribution of water masses is reproduced reasonably well, although with a saline bias in the intermediate water masses and a warm bias in the deep and bottom water of the Atlantic and Indian Oceans. The model underestimates the meridional transport of heat in the Atlantic Ocean. The simulated heat transport in the other basins, though, is in good agreement with observations. (orig.)

  15. Interactions Between the Thermohaline Circulation and Tropical Atlantic SST in a Coupled General Circulation Model

    Science.gov (United States)

    Miller, Ron; Jiang, Xing-Jian; Travis, Larry (Technical Monitor)

    2001-01-01

    Tropical Atlantic SST shows a (statistically well-defined) decadal time scale in a 104-year simulation of unforced variability by a coupled general circulation model (CGCM). The SST anomalies superficially resemble observed Tropical Atlantic variability (TAV), and are associated with changes in the atmospheric circulation. Brazilian rainfall is modulated with a decadal time scale, along with the strength of the Atlantic trade winds, which are associated with variations in evaporation and the net surface heat flux. However, in contrast to observed tropical Atlantic variability, the trade winds damp the associated anomalies in ocean temperature, indicating a negative feedback. Tropical SST anomalies in the CGCM, though opposed by the surface heat flux, are advected in from the Southern Hemisphere mid-latitudes. These variations modulate the strength of the thermohaline circulation (THC): warm, salty anomalies at the equator sink drawing cold, fresh mid-latitude water. Upon reaching the equator, the latter inhibit vertical overturning and advection from higher latitudes, which allows warm, salty anomalies to reform, returning the cycle to its original state. Thus, the cycle results from advection of density anomalies and the effect of these anomalies upon the rate of vertical overturning and surface advection. This decadal modulation of Tropical Atlantic SST and the thermohaline circulation is correlated with ocean heat transport to the Northern Hemisphere high latitudes and Norwegian Sea SST. Because of the central role of equatorial convection, we question whether this mechanism is present in the current climate, although we speculate that it may have operated in palaeo times, depending upon the stability of the tropical water column.

  16. Circulating Tumor Cell and Cell-free Circulating Tumor DNA in Lung Cancer.

    Science.gov (United States)

    Nurwidya, Fariz; Zaini, Jamal; Putra, Andika Chandra; Andarini, Sita; Hudoyo, Achmad; Syahruddin, Elisna; Yunus, Faisal

    2016-09-01

    Circulating tumor cells (CTCs) are tumor cells that are separated from the primary site or metastatic lesion and disseminate in blood circulation. CTCs are considered to be part of the long process of cancer metastasis. As a 'liquid biopsy', CTC molecular examination and investigation of single cancer cells create an important opportunity for providing an understanding of cancer biology and the process of metastasis. In the last decade, we have seen dramatic development in defining the role of CTCs in lung cancer in terms of diagnosis, genomic alteration determination, treatment response and, finally, prognosis prediction. The aims of this review are to understand the basic biology and to review methods of detection of CTCs that apply to the various types of solid tumor. Furthermore, we explored clinical applications, including treatment monitoring to anticipate therapy resistance as well as biomarker analysis, in the context of lung cancer. We also explored the potential use of cell-free circulating tumor DNA (ctDNA) in the genomic alteration analysis of lung cancer.

  17. Response of the South Atlantic circulation to an abrupt collapse of the Atlantic meridional overturning circulation

    Energy Technology Data Exchange (ETDEWEB)

    Laurian, Audine [University of Hawai' i at Manoa, International Pacific Research Center, School of Ocean and Earth Science and Technology, Honolulu, HI (United States); Drijfhout, Sybren S. [Royal Netherlands Meteorological Institute, De Bilt (Netherlands)

    2011-08-15

    The South Atlantic response to a collapse of the North Atlantic meridional overturning circulation (AMOC) is investigated in the ECHAM5/MPI-OM climate model. A reduced Agulhas leakage (about 3.1 Sv; 1 Sv = 10{sup 6} m{sup 3} s{sup -1}) is found to be associated with a weaker Southern Hemisphere (SH) supergyre and Indonesian throughflow. These changes are due to reduced wind stress curl over the SH supergyre, associated with a weaker Hadley circulation and a weaker SH subtropical jet. The northward cross-equatorial transport of thermocline and intermediate waters is much more strongly reduced than Agulhas leakage in relation with an AMOC collapse. A cross-equatorial gyre develops due to an anomalous wind stress curl over the tropics that results from the anomalous sea surface temperature gradient associated with reduced ocean heat transport. This cross-equatorial gyre completely blocks the transport of thermocline waters from the South to the North Atlantic. The waters originating from Agulhas leakage flow somewhat deeper and most of it recirculates in the South Atlantic subtropical gyre, leading to a gyre intensification. This intensification is consistent with the anomalous surface cooling over the South Atlantic. Most changes in South Atlantic circulation due to global warming, featuring a reduced AMOC, are qualitatively similar to the response to an AMOC collapse, but smaller in amplitude. However, the increased northward cross-equatorial transport of intermediate water relative to thermocline water is a strong fingerprint of an AMOC collapse. (orig.)

  18. Tablets: A Survey of Circulation Policies at Academic Libraries

    Science.gov (United States)

    Derr, Janice; Tolppanen, Bradley P.

    2015-01-01

    This article presents the results of a Web-based survey regarding the circulation of tablets in academic libraries. The survey, which was completed by 61 respondents, identifies the most common circulation policies and procedures used. These results will help other academic institutions develop their own policy or update existing ones. Areas of…

  19. Exercise limitation in patients with Fontan circulation : A review

    NARCIS (Netherlands)

    Takken, Tim; Tacken, Marieke H. P.; Blank, A. Christian; Hulzebos, Erik H.; Strengers, Jan L. M.; Helders, Paul J. M.

    2007-01-01

    The aim of the current literature study was to perform a literature review of the factors contributing to exercise limitation and physiological response to exercise in patients with Fontan circulation. In patients with Fontan circulation, peak oxygen uptake ranged from about 14.4 to 32.3 ml/min/kg,

  20. Impact of interocean exchange on the Atlantic overturning circulation

    NARCIS (Netherlands)

    Weijer, W.

    2001-01-01

    The awareness that human activity could change climate has greatly raised public and scientific interest in climate. One issue of present-day climate research is the stability of the thermohaline circulation. This overturning circulation, popularly known as the `conveyor belt', redistributes w

  1. Abrupt climate change and thermohaline circulation: Mechanisms and predictability

    OpenAIRE

    J. Marotzke

    2000-01-01

    The ocean's thermohaline circulation has long been recognized as potentially unstable and has consequently been invoked as a potential cause of abrupt climate change on all timescales of decades and longer. However, fundamental aspects of thermohaline circulation changes remain poorly understood.

  2. Abrupt climate change and thermohaline circulation: mechanisms and predictability.

    Science.gov (United States)

    Marotzke, J

    2000-02-15

    The ocean's thermohaline circulation has long been recognized as potentially unstable and has consequently been invoked as a potential cause of abrupt climate change on all timescales of decades and longer. However, fundamental aspects of thermohaline circulation changes remain poorly understood.

  3. Circulating osteogenic cells: implications for injury, repair, and regeneration

    DEFF Research Database (Denmark)

    Pignolo, Robert J; Kassem, Moustapha

    2011-01-01

    The aim of this review is to provide a critical reading of recent literature pertaining to the presence of circulating, fluid-phase osteoblastic cells and their possible contribution to bone formation. We have termed this group of cells collectively as circulating osteogenic precursor (COP) cells...

  4. Consortial Book Circulation Patterns: The OCLC-OhioLINK Study

    Science.gov (United States)

    O'Neill, Edward T.; Gammon, Julia A.

    2014-01-01

    The OhioLINK consortium and OCLC Research collected and analyzed circulation data for libraries within the consortium. The study, which examines the circulation of 28,475,701 items from more than 100 academic libraries, is the largest and most diverse compilation of academic usage data for books ever collected. The authors outline the study…

  5. Unique Protein Signature of Circulating Microparticles in Systemic Lupus Erythematosus

    DEFF Research Database (Denmark)

    Østergaard, Ole; Nielsen, Christoffer; Iversen, Line V

    2013-01-01

    To characterize the unique qualities of proteins associated with circulating subcellular material in systemic lupus erythematosus (SLE) patients compared with healthy controls and patients with other chronic autoimmune diseases.......To characterize the unique qualities of proteins associated with circulating subcellular material in systemic lupus erythematosus (SLE) patients compared with healthy controls and patients with other chronic autoimmune diseases....

  6. Conceptual models of the wind-driven and thermohaline circulation

    NARCIS (Netherlands)

    Drijfhout, S.S.; Marshall, D.P.; Dijkstra, H.A.

    2013-01-01

    Conceptual models are a vital tool for understanding the processes that maintain the global ocean circulation, both in nature and in complex numerical ocean models. In this chapter we provide a broad overview of our conceptual understanding of the wind-driven circulation, the thermohaline circulatio

  7. CellTracks cytometer for detection of circulating tumor cells

    NARCIS (Netherlands)

    Tibbe, A.G.J.; Kooi, van der A.; Groot, de M.R.; Vermes, I.

    2003-01-01

    Introduction: In patients with carcinomas, tumor cells are shed into the circulation. The number of the circulating tumor cells is low and technology is needed that has sufficient sensitivity and specificity to enumerate and characterize these cells. The CellTracks system was developed to provide an

  8. Transient Characteristics of Residual Meridional Circulation during Stratospheric Sudden Warming

    Institute of Scientific and Technical Information of China (English)

    DENG Shumei; CHEN Yuejuan; HUANG Yong; LUO Tao; BI Yun

    2011-01-01

    The residual meridional circulation derived from the transformed Eulerian-mean thermodynamic equation and continuity equation can be separated into two parts, the slowly varying diabatic circulation and the transient circulation, as demonstrated by others. We calculated and composite-analyzed the transient and diabatic circulation for 14 stratospheric sudden warming (SSW) events from 1979-2002 by using the daily ECMWF reanalysis data. Specifically, the transient residual meridional circulation was calculated both with and without inclusion of the eddy heat transport term in the transformed Eulerian-mean thermodynamic equation to investigate the importance of the eddy heat transport term. The results showed that calculations of transient residual meridional circulation present rapid variations during SSWs, with or without inclusion of the eddy heat transport term. Although the patterns of transient residual meridional circulation with the eddy heat transport term were similar to that without the eddy heat transport term during SSW, the magnitudes in the upper stratosphere and high-latitude regions differed. As for the diabatic circulation, its daily variations were small during SSW events, and its patterns were in agreement with its monthly average.

  9. Transient Characteristics of Residual Meridional Circulation during Stratospheric Sudden Warming

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The residual meridional circulation derived from the transformed Eulerian-mean thermodynamic equation and continuity equation can be separated into two parts,the slowly varying diabatic circulation and the transient circulation,as demonstrated by others.We calculated and composite-analyzed the transient and diabatic circulation for 14 stratospheric sudden warming(SSW) events from 1979-2002 by using the daily ECMWF reanalysis data.Specifically,the transient residual meridional circulation was calculated both with and without inclusion of the eddy heat transport term in the transformed Eulerian-mean thermodynamic equation to investigate the importance of the eddy heat transport term.The results showed that calculations of transient residual meridional circulation present rapid variations during SSWs,with or without inclusion of the eddy heat transport term.Although the patterns of transient residual meridional circulation with the eddy heat transport term were similar to that without the eddy heat transport term during SSW,the magnitudes in the upper stratosphere and high-latitude regions differed.As for the diabatic circulation,its daily variations were small during SSW events,and its patterns were in agreement with its monthly average.

  10. Circulation Price Elasticity in the Daily Newspaper Industry.

    Science.gov (United States)

    Grotta, Gerald L.; Taylor, Michael Lee

    Pricing of subscriptions and single copies has historically been arbitrary. Evidence indicates that the newspaper industry has tended to overestimate the elasticity of demand for newspaper circulation. This study analyzed price changes, circulation changes, and population changes for all daily newspapers in the United States between 1970 and 1975.…

  11. Internal air ventilated crawl-space : an evaluation of two manufactures

    OpenAIRE

    Rönngren, Andreas

    2002-01-01

    This Diploma work investigates internal air ventilated crawl-space in respect to construction and damp. The Diploma work assumes from a general description of crawl-space and general dump problems in ground construction. An internal air ventilated crawl-space is a construction where you take the ventilation air from the building and bring it down to the crawl-space and lets the air circulate before it passes through a retaining aggregate on the way out from the crawl-space. In this matter yo...

  12. Circulating Immune Complexes among Diabetic Children

    Directory of Open Access Journals (Sweden)

    George Nicoloff

    2004-01-01

    Full Text Available Insulin dependent diabetes mellitus (IDDM is an autoimmune disease associated with the presence of different types of autoantibodies. The presence of these antibodies and the corresponding antigens in the circulation leads to the formation of circulating immune complexes (CIC. CIC are known to persist in the blood for long periods of time. Such CIC following deposition in the small blood vessels have the potential to lead to microangiopathy with debilitating clinical consequences. The aim of our pilot study was to investigate whether a correlation exists between CIC and the development of microvascular complications in diabetic children. Isolation of a new glycoprotein complement inhibition factor (CIF from the parasitic plant Cuscuta europea seed, which appears to bind specifically to complement component C3 has provided an unique tool for the measurement of immune complexes by means of ELISA-type techniques (CIF-ELISA. We studied the levels of CIC (IgG, IgM and IgA in 58 diabetic children (mean age 12.28±4.04 years, diabetes duration 5.3±3.7 years, 29 of them had vascular complications (group 1 and the other 29 were without vascular complications (group 2. As controls, we studied sera samples from 21 healthy children (mean age 13.54±4.03 years. Sera from the diabetic patients showed statistically significant higher levels of CIC IgG ( p=0.03 than sera from the control group. In sera from group 1 values of CIC IgG showed statistically significant higher levels than controls (0.720±0.31 vs. 0.46±0.045; p=0.011 Sera from 59% of the patients were positive for CIC IgG, 36% for CIC IgM and 9% for CIC IgA. Among 26 patients with microalbuminuria, sera from 17/26 (65% were positive for CIC IgG, 8/26 (31% for CIC IgM and 2/26 (8% for CIC IgA. CIC IgG correlated with HbA1c (r=0.51; p=0.005 and microalbuminuria (r=0.42, p=0.033. CIC IgA correlated with age (r=0.44, p=0.03. CIC IgM correlated with the duration of diabetes (r=0.63, p=0.02. These

  13. Using Green's Functions to initialize and adjust a global, eddying ocean biogeochemistry general circulation model

    Science.gov (United States)

    Brix, H.; Menemenlis, D.; Hill, C.; Dutkiewicz, S.; Jahn, O.; Wang, D.; Bowman, K.; Zhang, H.

    2015-11-01

    The NASA Carbon Monitoring System (CMS) Flux Project aims to attribute changes in the atmospheric accumulation of carbon dioxide to spatially resolved fluxes by utilizing the full suite of NASA data, models, and assimilation capabilities. For the oceanic part of this project, we introduce ECCO2-Darwin, a new ocean biogeochemistry general circulation model based on combining the following pre-existing components: (i) a full-depth, eddying, global-ocean configuration of the Massachusetts Institute of Technology general circulation model (MITgcm), (ii) an adjoint-method-based estimate of ocean circulation from the Estimating the Circulation and Climate of the Ocean, Phase II (ECCO2) project, (iii) the MIT ecosystem model "Darwin", and (iv) a marine carbon chemistry model. Air-sea gas exchange coefficients and initial conditions of dissolved inorganic carbon, alkalinity, and oxygen are adjusted using a Green's Functions approach in order to optimize modeled air-sea CO2 fluxes. Data constraints include observations of carbon dioxide partial pressure (pCO2) for 2009-2010, global air-sea CO2 flux estimates, and the seasonal cycle of the Takahashi et al. (2009) Atlas. The model sensitivity experiments (or Green's Functions) include simulations that start from different initial conditions as well as experiments that perturb air-sea gas exchange parameters and the ratio of particulate inorganic to organic carbon. The Green's Functions approach yields a linear combination of these sensitivity experiments that minimizes model-data differences. The resulting initial conditions and gas exchange coefficients are then used to integrate the ECCO2-Darwin model forward. Despite the small number (six) of control parameters, the adjusted simulation is significantly closer to the data constraints (37% cost function reduction, i.e., reduction in the model-data difference, relative to the baseline simulation) and to independent observations (e.g., alkalinity). The adjusted air-sea gas

  14. Connectable solar air collectors

    Energy Technology Data Exchange (ETDEWEB)

    Oestergaard Jensen, S.; Bosanac, M.

    2002-02-01

    The project has proved that it is possible to manufacture solar air collector panels, which in an easy way can be connected into large collector arrays with integrated ducting without loss of efficiency. The developed connectable solar air collectors are based on the use of matrix absorbers in the form of perforated metal sheets. Three interconnected solar air collectors of the above type - each with an transparent area of approx. 3 m{sup 2} - was tested and compared with parallel tests on two single solar air collectors also with a transparent area of approx. 3 m{sup 2} One of the single solar air collectors has an identical absorber as the connectable solar air collectors while the absorber of the other single solar air collector was a fibre cloth. The efficiency of the three solar air collectors proved to be almost identical in the investigated range of mass flow rates and temperature differences. The solar air collectors further proved to be very efficient - as efficient as the second most efficient solar air collectors tested in the IEA task 19 project Solar Air Systems. Some problems remain although to be solved: the pressure drop across especially the connectable solar air collectors is too high - mainly across the inlets of the solar air collectors. It should, however, be possible to considerably reduce the pressure losses with a more aerodynamic design of the inlet and outlet of the solar air collectors; The connectable solar air collectors are easy connectable but the air tightness of the connections in the present form is not good enough. As leakage leads to lower efficiencies focus should be put on making the connections more air tight without loosing the easiness in connecting the solar air collectors. As a spin off of the project a simple and easy way to determine the efficiency of solar, air collectors for pre-heating of fresh air has been validated. The simple method of determining the efficiency has with success been compared with an advance method

  15. Compressed Sensing for Thoracic MRI with Partial Random Circulant Matrices

    Directory of Open Access Journals (Sweden)

    Hideaki Haneishi

    2012-03-01

    Full Text Available The use of Circulant matrix as the sensing matrix in compressed sensing (CS scheme has recently been proposed to overcome the limitation of random or partial Fourier matrices. Aside from reducing computational complexity, the use of circulant matrix for MR image offers the feasibility in hardware implementations. This paper presents the simulation of compressed sensing for thoracic MR imaging with circulant matrix as the sensing matrix. The comparisons of reconstruction of three different type MR images using circulant matrix are investigated in term of number of samples, number of iteration and signal to noise ratio (SNR. The simulation results showed that Circulant Matrix works efficiently for encoding the MR image of respiratory organ, especially for smooth and sparse image in spatial domain.

  16. The role of the thermohaline circulation in abrupt climate change.

    Science.gov (United States)

    Clark, Peter U; Pisias, Nicklas G; Stocker, Thomas F; Weaver, Andrew J

    2002-02-21

    The possibility of a reduced Atlantic thermohaline circulation in response to increases in greenhouse-gas concentrations has been demonstrated in a number of simulations with general circulation models of the coupled ocean-atmosphere system. But it remains difficult to assess the likelihood of future changes in the thermohaline circulation, mainly owing to poorly constrained model parameterizations and uncertainties in the response of the climate system to greenhouse warming. Analyses of past abrupt climate changes help to solve these problems. Data and models both suggest that abrupt climate change during the last glaciation originated through changes in the Atlantic thermohaline circulation in response to small changes in the hydrological cycle. Atmospheric and oceanic responses to these changes were then transmitted globally through a number of feedbacks. The palaeoclimate data and the model results also indicate that the stability of the thermohaline circulation depends on the mean climate state.

  17. WEATHER AND CIRCULATION TYPES ACCOMPANYING THERMAL AND HUMIDITY CONDITIONS UNFAVOURABLE TO THE HUMAN HEALTH IN SUMMER IN KRAKOW (POLAND

    Directory of Open Access Journals (Sweden)

    D. CIARANEK

    2013-03-01

    Full Text Available The paper presents the results of a study analysing the frequency of occurrence and patterns of change in the human perception of temperature in relation to types of weather and circulation in Krakow. The Humidex index used for the purpose was determined at three measurement times (6, 12, 18 UTC with data spanning the period 1961-2012. The frequency of occurrence of all types of discomfort situation was found to be on the increase. Days with some discomfort occurred most frequently during non-advection situations, (especially in the centre of a meteorological high or anticyclonic wedge, accompanied by transformed polar maritime air or continental polar air. The weather varied greatly on such days, from cloudy to sunny and with or without precipitation. Days with high discomfort levels were associated with the advection of tropical air accompanied typically by very hot, sweltering weather, and by dry, very sunny weather.

  18. Characterising the relationship between weather extremes in Europe and synoptic circulation features

    Directory of Open Access Journals (Sweden)

    S. Pfahl

    2014-02-01

    Full Text Available Extreme weather events in Europe are closely linked to anomalies of the atmospheric circulation and in particular to circulation features like cyclones and atmospheric blocking. In this study, this linkage is systematically characterised with the help of conditional cyclone and blocking frequencies during precipitation, wind gust and temperature extremes at various locations in Europe. Such conditional frequency fields can serve as a dynamical fingerprint of the extreme events and yield insights into their most important physical driving mechanisms. Precipitation extremes over the ocean and over flat terrain are shown to be closely related to cyclones in the vicinity and the associated dynamical lifting. For extreme precipitation over complex terrain, cyclone anomalies are found at more remote locations, favouring the flow of moist air towards the topography. Wind gust extremes are associated with cyclone and blocking anomalies in opposite directions, with the cyclones occurring mostly over the North and Baltic Seas for extreme events in central Europe. This setting is associated with pronounced surface pressure gradients and thus high near-surface wind velocities. Hot temperature extremes in northern and central Europe typically occur in the vicinity of a blocking anticyclone, where subsidence and radiative forcing are strong. Over southern Europe, blocking anomalies are shifted more to the north or northeast, indicating a more important role of warm air advection. Large-scale flow conditions for cold extremes are similar at many locations in Europe, with blocking anomalies over the North Atlantic and northern Europe and cyclone anomalies southeast of the cold extreme, both contributing to the advection of cold air masses. This characterisation of synoptic-scale forcing mechanisms can be helpful for better understanding and anticipating weather extremes and their long-term changes.

  19. A measure of the degree of inhomogeneity in a distribution and its application in characterising the particle circulation in a fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Garncarek, Z. (Inst. of Mathematics, Pedagogical Univ. of Opole (Poland)); Przybylski, L. (Inst. of Tech., Pedagogical Univ. of Opole (Poland)); Botterill, J.S.M. (School of Chemical Engineering, Univ. of Birmingham (United Kingdom)); Bridgwater, J. (School of Chemical Engineering, Univ. of Birmingham (United Kingdom)); Broadbent, C.J. (School of Chemical Engineering, Univ. of Birmingham (United Kingdom))

    1994-09-01

    A quantitative method to evaluate variational processes such as particle circulation in a fluidized bed is presented. It involves the calculation of H, an index of the degree of inhomogeneity in the tracer circulation in standard measure. The position of a given particle in a rectangular fluidized bed was followed using Positron Emission Particle Tracking. This technique is able to locate a labelled solid and construct a three-dimensional trajectory of its movement. The degree of inhomogeneity in the tracer distribution was then calculated from the observations. The values of H for the tracer movement when the bed is operated with a differential air supply across the distributor to stimulate gross solids circulation, suggest that there are relatively large regions of the bed in which the presence of the tracer is much less frequent than elsewhere. This lack of homogeneity in the tracer particle circulation is consistent with visual observation of particle circulation in the investigated bed. Increase in H with increasing length of the duration of the test is consistent with a stable circulation pattern. H affords a quantitative measure of how the fluidized bed parameters influence the particles movement. (orig.)

  20. NUCLA Circulating Atmospheric Fluidized Bed Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    1992-02-01

    The report summarizes unit operating experience and test program progress for 1989 on Colorado-Ute Electric Association's Nucla CFB Demonstration Program. During this period, the objectives of the Nucla Station operating group were to correct problems with refractory durability, resolve primary air fan capacity limitations, complete the high ash and high sulfur coal tests, switch to Salt Creek coal as the operating fuel, and make the unit available for testing without capacity restrictions. Each of these objectives was addressed and accomplished, to varying degrees, except for the completion of the high sulfur coal acceptance tests. (VC)

  1. Circulating CXCL16 in Diabetic Kidney Disease

    Directory of Open Access Journals (Sweden)

    Usama Elewa

    2016-09-01

    Full Text Available Background/Aims: Chronic kidney disease and, specifically, diabetic kidney disease, is among the fastest increasing causes of death worldwide. A better understanding of the factors contributing to the high mortality may help design novel monitoring and therapeutic approaches. CXCL16 is both a cholesterol receptor and a chemokine with a potential role in vascular injury and inflammation. We aimed at identifying predictors of circulating CXCL16 levels in diabetic patients with chronic kidney disease. Methods: We have now studied plasma CXCL16 in 134 European patients with diabetic kidney disease with estimated glomerular filtration rate (eGFR categories G1-G4 and albuminuria categories A1-A3, in order to identify factors influencing plasma CXCL16 in this population. Results: Plasma CXCL16 levels were 4.0±0.9 ng/ml. Plasma CXCL16 increased with increasing eGFR category from G1 to G4 (that is, with decreasing eGFR values and with increasing albuminuria category. Plasma CXCL16 was higher in patients with prior cardiovascular disease (4.33±1.03 vs 3.88±0.86 ng/ml; p=0.013. In multivariate analysis, eGFR and serum albumin had an independent and significant negative correlation with plasma CXCL16. Conclusion: In diabetic kidney disease patients, GFR and serum albumin independently predicted plasma CXCL16 levels.

  2. Circulating microRNAs in Cardiovascular Diseases.

    Science.gov (United States)

    Orlicka-Płocka, Marta; Gurda, Dorota; Fedoruk-Wyszomirska, Agnieszka; Smolarek, Iwona; Wyszko, Eliza

    2016-01-01

    Cardiovascular Diseases (CD) are currently one of the most common causes of death. Because heart related deaths occur on such an enormous scale this phenomenon is referred to as an epidemic. Chronic and acute injury of the heart could be an effect of cardiac remodeling, which is a result of molecular, cellular and interstitial changes, influenced by hemodynamic load or neurohormonal activation (Cohn et al., 2000). These small deviations in cardiac activity and morphology may lead to an enormous negative effect. Despite a significant progress, knowledge of standard risk factors for cardiovascular diseases has become less and less effective, which is why predicting and seeking an appropriate treatment is very challenging. As a result, there is a growing interest in finding new markers of the CD. MicroRNAs (miRNAs), are short, non-coding RNAs responsible for regulation of gene expression at the post-transcriptional level. Among them that have the greatest potential are microRNA molecules that circulate in the blood plasma or serum, that are related to direct activation of signaling pathways, implicated in the aging process and thus for the development of cardiovascular disease. This paper is a summary of the current state of knowledge on miRNAs, their biogenesis and potential role as biomarkers to diagnose heart disease.

  3. Circulation and Dissipation on Hot Jupiters

    Science.gov (United States)

    Li, J.; Goodman, J.

    2010-12-01

    Many global circulation models predict supersonic zonal winds and large vertical shears in the atmospheres of short-period Jovian exoplanets. Using linear analysis and nonlinear local simulations, we investigate hydrodynamic dissipation mechanisms to balance the thermal acceleration of these winds. The adiabatic Richardson criterion remains a good guide to linear stability, although thermal diffusion allows some modes to violate it at very long wavelengths and very low growth rates. Nonlinearly, wind speeds saturate at Mach numbers ≈2 and Richardson numbers lsim1/4 for a broad range of plausible diffusivities and forcing strengths. Turbulence and vertical mixing, though accompanied by weak shocks, dominate the dissipation, which appears to be the outcome of a recurrent Kelvin-Helmholtz instability. An explicit shear viscosity, as well as thermal diffusivity, is added to ZEUS to capture dissipation outside of shocks. The wind speed is neither monotonic nor single valued for a range of shear viscosities larger than about 10-3 of the sound speed times the pressure scale height. Coarsening the numerical resolution can also increase the speed. Hence global simulations that are incapable of representing vertical turbulence and shocks, either because of reduced physics or because of limited resolution, may overestimate wind speeds. We recommend that such simulations include artificial dissipation terms to control the Mach and Richardson numbers and to capture mechanical dissipation as heat.

  4. Global warming and thermohaline circulation stability.

    Science.gov (United States)

    Wood, Richard A; Vellinga, Michael; Thorpe, Robert

    2003-09-15

    The Atlantic thermohaline circulation (THC) plays an important role in global climate. Theoretical and palaeoclimatic evidence points to the possibility of rapid changes in the strength of the THC, including a possible quasi-permanent shutdown. The climatic impacts of such a shutdown would be severe, including a cooling throughout the Northern Hemisphere, which in some regions is greater in magnitude than the changes expected from global warming in the next 50 years. Other climatic impacts would likely include a severe alteration of rainfall patterns in the tropics, the Indian subcontinent and Europe. Modelling the future behaviour of the THC focuses on two key questions. (i) Is a gradual weakening of the THC likely in response to global warming, and if so by how much? (ii) Are there thresholds beyond which rapid or irreversible changes in the THC are likely? Most projections of the response of the THC to increasing concentrations of greenhouse gases suggest a gradual weakening over the twenty-first century. However, there is a wide variation between different models over the size of the weakening. Rapid or irreversible THC shutdown is considered a low-probability (but high-impact) outcome; however, some climate models of intermediate complexity do show the possibility of such events. The question of the future of the THC is beset with conceptual, modelling and observational uncertainties, but some current and planned projects show promise to make substantial progress in tackling these uncertainties in future.

  5. Isolation of Circulating Tumor Cells by Dielectrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Gascoyne, Peter R. C., E-mail: pgascoyn@mdanderson.org [Department of Imaging Physics Research, The University of Texas M.D. Anderson Cancer Center Unit 951, 1515 Holcombe Boulevard, Houston, TX 77030 (United States); Shim, Sangjo [Department of Imaging Physics Research, The University of Texas M.D. Anderson Cancer Center Unit 951, 1515 Holcombe Boulevard, Houston, TX 77030 (United States); Department of Biomedical Engineering, The University of Texas at Austin, 1 University Station, C0800, Austin, TX 78712 (United States); Present address: Micro & Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, Urbana, 208 North Wright Street, Urbana, IL 61801 (United States)

    2014-03-12

    Dielectrophoresis (DEP) is an electrokinetic method that allows intrinsic dielectric properties of suspended cells to be exploited for discrimination and separation. It has emerged as a promising method for isolating circulation tumor cells (CTCs) from blood. DEP-isolation of CTCs is independent of cell surface markers. Furthermore, isolated CTCs are viable and can be maintained in culture, suggesting that DEP methods should be more generally applicable than antibody-based approaches. The aim of this article is to review and synthesize for both oncologists and biomedical engineers interested in CTC isolation the pertinent characteristics of DEP and CTCs. The aim is to promote an understanding of the factors involved in realizing DEP-based instruments having both sufficient discrimination and throughput to allow routine analysis of CTCs in clinical practice. The article brings together: (a) the principles of DEP; (b) the biological basis for the dielectric differences between CTCs and blood cells; (c) why such differences are expected to be present for all types of tumors; and (d) instrumentation requirements to process 10 mL blood specimens in less than 1 h to enable routine clinical analysis. The force equilibrium method of dielectrophoretic field-flow fractionation (DEP-FFF) is shown to offer higher discrimination and throughput than earlier DEP trapping methods and to be applicable to clinical studies.

  6. The Zonal Structure of the Hadley Circulation

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A discussion of the mass transport of the Hadley circulation is presented, with regard to its longitudinal structure. Data from the NCEP/NCAR reanalysis data set for the period 1948-2005 is examined,focusing on the solsticial seasons of June-August and December-February. Quantitative estimates have been extracted from the data to observe connections between the zonal mean of the upper tropospheric north/south mass transports and their relationship to the driving factor of tropical precipitation (implying latent heat release) and subsidence in the subtropical high pressure belts. The longitudinal structure of this flow is then examined with regard to these three main variables. The poleward upper tropospheric transport has four (JJA) or three (DJF) main branches, which link regions of major precipitation with corresponding regions of large subsidence, and one (June, July, August) or two (December, January, February) reverse branches. This structure has remained stable over the past sixty years. Although the total upper tropospheric transport in each season is less than the total sinking transport in the target subtropical high pressure belt, this does not apply to the individual branches, the balance being made up by the upper tropospheric reverse transports. An analysis of correlations between all of these various components shows, however, that the complete picture is more complex, with some precipitation regions being linked to subsidence regions outside their own branch.

  7. Isolation of Circulating Tumor Cells by Dielectrophoresis

    Directory of Open Access Journals (Sweden)

    Peter R. C. Gascoyne

    2014-03-01

    Full Text Available Dielectrophoresis (DEP is an electrokinetic method that allows intrinsic dielectric properties of suspended cells to be exploited for discrimination and separation. It has emerged as a promising method for isolating circulation tumor cells (CTCs from blood. DEP-isolation of CTCs is independent of cell surface markers. Furthermore, isolated CTCs are viable and can be maintained in culture, suggesting that DEP methods should be more generally applicable than antibody-based approaches. The aim of this article is to review and synthesize for both oncologists and biomedical engineers interested in CTC isolation the pertinent characteristics of DEP and CTCs. The aim is to promote an understanding of the factors involved in realizing DEP-based instruments having both sufficient discrimination and throughput to allow routine analysis of CTCs in clinical practice. The article brings together: (a the principles of DEP; (b the biological basis for the dielectric differences between CTCs and blood cells; (c why such differences are expected to be present for all types of tumors; and (d instrumentation requirements to process 10 mL blood specimens in less than 1 h to enable routine clinical analysis. The force equilibrium method of dielectrophoretic field-flow fractionation (DEP-FFF is shown to offer higher discrimination and throughput than earlier DEP trapping methods and to be applicable to clinical studies.

  8. Circulating Humorous Antitobacco Videos on Social Media.

    Science.gov (United States)

    Lee, Moon J; Chen, Fannin

    2017-03-01

    We investigated whether exposure to same humorous antitobacco videos via different types of social media platforms and contexts (health vs. humor) influences individual's health risk perceptions, attitudes, and behavioral intents. An experiment with a 2 (social media types: YouTube and Facebook) × 2 (message contexts: health-focused and humor-focused contexts) factorial design was conducted. It was found that those who watched the humorous antitobacco videos on Facebook in the health-context exhibited a higher level of risk perception of smoking, less positive attitude toward smokers, and a higher level of intention to avoid smoking in the future than the participants who viewed the same videos on YouTube in the health-context or on Facebook in the humor-context. These findings provide useful practical guidelines in using social media for health communication/promotion. Humorous health promotion messages are best circulated on social networking sites such as Facebook accompanied by others' support for the given health topic (i.e., in health-contexts). Practical/theoretical implications and limitations of the study were further discussed in this article.

  9. Identification and frequency of atmospheric circulation patterns causing spring frost in the northern French vineyards using the objective version of the Hess-Brezowsky classification

    Science.gov (United States)

    Quénol, H.; Planchon, O.; Wahl, L.

    2009-04-01

    The possible impacts of climate change at small spatial scales are still very little known. The knowledge of the climate risks at small scales is yet essential for agricultural activities and productions like vine growing, because of their serious economic impacts. Because of their relatively high latitude, the vineyards of the northern Half of France are subjected to spring frost, which can cause serious damages e.g. in the Champagne area on April the 8th, 2003. A detailed study of the variability and frequency of spring frost events in four vineyards (Loire Valley, Champagne, Burgundy and Alsace) was carried out within the framework of the RICLIM-CNRS 2663 multidisciplinary Research Group "Climate Risks" and was supported by the research program TERVICLIM (ANR-JC07-194103) and by the MAIF Foundation (program about air-mass circulation dynamics and climate risks). The northern Half of France is included in the Cfb type of climate (according to the Köppen's classification) of northwestern and central Europe. However, the combined effects of the latitude, the continentality and the topography involve varied regional climates. Among the four studied wine-producing areas, the Loire Valley area is the warmest, the Champagne area is the coolest in summer, and eastern Burgundy and especially Alsace are the most subjected to the continentality effect (highest annual temperature oscillation and highest rainfall amounts in summer). Therefore, these areas are not equally subjected to the frost risk. Spring is a key season for the vine growing and during frost-producing weather patterns, northern France is subjected to a high spatial variability of temperature at regional and local scales. During the period 1960-2007, the number of spring frost day events was three times as high in Colmar (Alsace) than in Saumur (Loire Valley). Among the four wine-producing areas, Alsace records the most hard and frequent frosts in early spring, while the Champagne area records the latest

  10. System and method for conditioning intake air to an internal combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Sellnau, Mark C.

    2015-08-04

    A system for conditioning the intake air to an internal combustion engine includes a means to boost the pressure of the intake air to the engine and a liquid cooled charge air cooler disposed between the output of the boost means and the charge air intake of the engine. Valves in the coolant system can be actuated so as to define a first configuration in which engine cooling is performed by coolant circulating in a first coolant loop at one temperature, and charge air cooling is performed by coolant flowing in a second coolant loop at a lower temperature. The valves can be actuated so as to define a second configuration in which coolant that has flowed through the engine can be routed through the charge air cooler. The temperature of intake air to the engine can be controlled over a wide range of engine operation.

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

    Institute of Scientific and Technical Information of China (English)

    Wang Kexiong; Zhang Laibin; Jiang Hongwei

    2007-01-01

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

  12. AirCompare

    Data.gov (United States)

    U.S. Environmental Protection Agency — AirCompare contains air quality information that allows a user to compare conditions in different localities over time and compare conditions in the same location...

  13. Allegheny County Air Quality

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Air quality data from Allegheny County Health Department monitors throughout the county. Air quality monitored data must be verified by qualified individuals before...

  14. Air Quality Facilities

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — Facilities with operating permits for Title V of the Federal Clean Air Act, as well as facilities required to submit an air emissions inventory, and other facilities...

  15. Indoor Air Pollution

    Science.gov (United States)

    We usually think of air pollution as being outdoors, but the air in your house or office could also be polluted. Sources of indoor pollution include Mold and pollen Tobacco smoke Household products ...

  16. Air Quality System (AQS)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Air Quality System (AQS) database contains measurements of air pollutant concentrations from throughout the United States and its territories. The measurements...

  17. A seasonal air transport climatology for Kenya

    Science.gov (United States)

    Gatebe, C. K.; Tyson, P. D.; Annegarn, H.; Piketh, S.; Helas, G.

    1999-06-01

    A climatology of air transport to and from Kenya has been developed using kinematic trajectory modeling. Significant months for trajectory analysis have been determined from a classification of synoptic circulation fields. Five-point back and forward trajectory clusters to and from Kenya reveal that the transport corridors to Kenya are clearly bounded and well defined. Air reaching the country originates mainly from the Saharan region and northwestern Indian Ocean of the Arabian Sea in the Northern Hemisphere and from the Madagascan region of the Indian Ocean in the Southern Hemisphere. Transport from each of these source regions show distinctive annual cycles related to the northeasterly Asian monsoon and the southeasterly trade wind maximum over Kenya in May. The Saharan transport in the lower troposphere is at a maximum when the subtropical high over northern Africa is strongly developed in the boreal winter. Air reaching Kenya between 700 and 500 hPa is mainly from Sahara and northwest Indian Ocean in the months of January and March, which gives way to southwest Indian Ocean flow in May and November. In contrast, air reaching Kenya at 400 hPa is mainly from southwest Indian Ocean in January and March, which is replaced by Saharan transport in May and November. Transport of air from Kenya is invariant, both spatially and temporally, in the tropical easterlies to the Congo Basin and Atlantic Ocean in comparison to the transport to the country. Recirculation of air has also been observed but on a limited and often local scale and not to the extent reported in southern Africa.

  18. Utility of AIRS Retrievals for Climate Studies

    Science.gov (United States)

    Molnar, Guyla I.; Susskind, Joel

    2007-01-01

    Satellites provide an ideal platform to study the Earth-atmosphere system on practically all spatial and temporal scales. Thus, one may expect that their rapidly growing datasets could provide crucial insights not only for short-term weather processes/predictions but into ongoing and future climate change processes as well. Though Earth-observing satellites have been around for decades, extracting climatically reliable information from their widely varying datasets faces rather formidable challenges. AIRS/AMSU is a state of the art infrared/microwave sounding system that was launched on the EOS Aqua platform on May 4, 2002, and has been providing operational quality measurements since September 2002. In addition to temperature and atmospheric constituent profiles, outgoing longwave radiation and basic cloud parameters are also derived from the AIRS/AMSU observations. However, so far the AIRS products have not been rigorously evaluated and/or validated on a large scale. Here we present preliminary assessments of monthly and 8-day mean AIRS "Version 4.0" retrieved products (available to the public through the DAAC at NASA/GSFC) to assess their utility for climate studies. First we present "consistency checks" by evaluating the time series of means, and "anomalies" (relative to the first 4 full years' worth of AIRS "climate statistics") of several climatically important retrieved parameters. Finally, we also present preliminary results regarding interrelationships of some of these geophysical variables, to assess to what extent they are consistent with the known physics of climate variability/change. In particular, we find at least one observed relationship which contradicts current general circulation climate (GCM) model results: the global water vapor climate feedback which is expected to be strongly positive is deduced to be slightly negative (shades of the "Lindzen effect"?). Though the current AIRS climatology covers only -4.5 years, it will hopefully extend much

  19. Air Power and Warfare

    Science.gov (United States)

    1978-09-01

    Memorial, 1963. (T) 767.8 A3 ser .3, V.4) Air war against Germany and Italy, 1939-1943. Canberra: Australian War Memorial, 1954. (D 767.8 A3 Ser .3, V.3...et al. Air poder indivisible Air University Ouarterly Review 2:5-18, Fall 1950. Spaatz, Crrl. Air-power odds against us. Readers Digest 58:11-14, June

  20. Indoor air quality

    DEFF Research Database (Denmark)

    Jensen, Trine Susanne; Recevska, Ieva

     The objective of the 35th specific agreement is to provide support to the EEA activities in Environment and Health (E&H) on the topic of indoor air quality. The specific objectives have been to provide an overview of indoor air related projects in EU and indoor air related policies as well...... as idenfiying "good practices" to reduce health impact of indoor air exposure and suggest areas for future improvements....

  1. Large-scale urbanization effects on eastern Asian summer monsoon circulation and climate

    Science.gov (United States)

    Chen, Haishan; Zhang, Ye; Yu, Miao; Hua, Wenjian; Sun, Shanlei; Li, Xing; Gao, Chujie

    2016-07-01

    Impacts of large-scale urbanization over eastern China on East Asian summer monsoon circulation and climate are investigated by comparing three 25-year climate simulations with and without incorporating modified land cover maps reflecting two different idealized large-scale urbanization scenarios. The global atmospheric general circulation model CAM4.0 that includes an urban canopy parameterization scheme is employed in this study. The large-scale urbanization over eastern China leads to a significant warming over most of the expanded urban areas, characterized by an increase of 3 K for surface skin temperature, 2.25 K for surface air temperature, significant warming of both daily minimum and daily maximum air temperatures, and 0.4 K for the averaged urban-rural temperature difference. The urbanization is also accompanied by an increase in surface sensible heat flux, a decrease of the net surface shortwave and long-wave radiation, and an enhanced surface thermal heating to the atmosphere in most Eastern Asia areas. It is noted that the responses of the East Asian summer monsoon circulation exhibits an evident month-to-month variation. Across eastern China, the summer monsoon in early summer is strengthened by the large-scale urbanization, but weakened (intensified) over southern (northern) part of East Asia in late summer. Meanwhile, early summer precipitation is intensified in northern and northeastern China and suppressed in south of ~35°N, but late summer precipitation is evidently suppressed over northeast China, the Korean Peninsula and Japan with enhancements in southern China, the South China Sea, and the oceanic region south and southeast of the Taiwan Island. This study highlights the evidently distinct month-to-month responses of the monsoon system to the large-scale urbanization, which might be attributed to different basic states, internal feedbacks (cloud, rainfall) as well as a dynamic adjustment of the atmosphere. Further investigation is required

  2. We Pollute the Air

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    1.Clean air is important to good health.If the aircontains impurities,they may be absorbed by ourbodies and make us ill.We need clean air,butunfortunately,air pollution is generally present,especially in cities. 2.Our cities have many factories,which we need tomake food products,clothing and many other things.

  3. Air Pollution Training Programs.

    Science.gov (United States)

    Public Health Service (DHEW), Rockville, MD.

    This catalog lists the universities, both supported and not supported by the Division of Air Pollution, which offer graduate programs in the field of air pollution. The catalog briefly describes the programs and their entrance requirements, the requirements, qualifications and terms of special fellowships offered by the Division of Air Pollution.…

  4. Carbon dioxide, ground air and carbon cycling in Gibraltar karst

    Science.gov (United States)

    Mattey, D. P.; Atkinson, T. C.; Barker, J. A.; Fisher, R.; Latin, J.-P.; Durrell, R.; Ainsworth, M.

    2016-07-01

    We put forward a general conceptual model of CO2 behaviour in the vadose zone of karst aquifers, based on physical principles of air flow through porous media and caves, combined with a geochemical interpretation of cave monitoring data. This 'Gibraltar model' links fluxes of water, air and carbon through the soil with the porosity of the vadose zone, the circulation of ground air and the ventilation of caves. Gibraltar hosts many natural caves whose locations span the full length and vertical range of the Rock. We report results of an 8-year monitoring study of carbon in soil organic matter and bedrock carbonate, dissolved inorganic carbon in vadose waters, and gaseous CO2 in soil, cave and ground air. Results show that the regime of cave air CO2 results from the interaction of cave ventilation with a reservoir of CO2-enriched ground air held within the smaller voids of the bedrock. The pCO2 of ground air, and of vadose waters that have been in close contact with it, are determined by multiple factors that include recharge patterns, vegetation productivity and root respiration, and conversion of organic matter to CO2 within the soil, the epikarst and the whole vadose zone. Mathematical modelling and field observations show that ground air is subject to a density-driven circulation that reverses seasonally, as the difference between surface and underground temperatures reverses in sign. The Gibraltar model suggests that cave air pCO2 is not directly related to CO2 generated in the soil or the epikarstic zone, as is often assumed. Ground air CO2 formed by the decay of organic matter (OM) washed down into the deeper unsaturated zone is an important additional source of pCO2. In Gibraltar the addition of OM-derived CO2 is the dominant control on the pCO2 of ground air and the Ca-hardness of waters within the deep vadose zone. The seasonal regime of CO2 in cave air depends on the position of a cave in relation to the density-driven ground air circulation pattern which

  5. High performance millimeter-wave microstrip circulators and isolators

    Science.gov (United States)

    Shih, Ming; Pan, J. J.

    1990-01-01

    Millimeter wave systems, phased array antennas, and high performance components all require wideband circulators (and isolators) to perform diplexing and switching, to improve isolation and Voltage Standing Wave Ratio (VSWR), and to construct IMPATT diode reflection amplifiers. Presently, most of the millimeter-wave circulators and isolators are available in the configurations of waveguide or stripline, both of which suffer from the shortcomings of bulky size/weight, narrow bandwidth, and poor compatibility with monolithic millimeter-wave integrated circuits (MMIC). MMW microstrip circulators/isolators can eliminate or improve these shortcomings. Stub-tuned microstrip circulator configuration were developed utilizing the electromagnetic fields perturbation technique, the adhesion problems of microstrip metallization on new ferrite substrate were overcome, the fabrication, assembly, packaging techniques were improved, and then successfully designed, fabricated a Ka band circulator which has isolation and return loss of greater than 16dB, insertion loss less than 0.7dB. To assess the steady and reliable performance of the circulator, a temperature cycling test was done over the range of -20 to +50 C for 3 continuous cycles and found no significant impact or variation of circulator performance.

  6. On affine connections in a Riemannian manifold with a circulant metric and two circulant affinor structures

    CERN Document Server

    Dokuzova, Iva

    2010-01-01

    In the present paper it is considered a class V of 3-dimensional Riemannian manifolds M with a metric g and two affinor tensors q and S. It is defined another metric \\bar{g} in M. The local coordinates of all these tensors are circulant matrices. It is found: 1)\\ a relation between curvature tensors R and \\bar{R} of g and \\bar{g}, respectively; 2)\\ an identity of the curvature tensor R of g in the case when the curvature tensor \\bar{R} vanishes; 3)\\ a relation between the sectional curvature of a 2-section of the type \\{x, qx\\} and the scalar curvature of M.

  7. Co-combustion of olive cake with lignite coal in a circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Aysel T. Atimtay; Huseyin Topal [Middle East Technical University, Ankara (Turkey). Department of Environmental Engineering

    2004-05-01

    In this study, olive cake (OC) was co-fired with coal in a circulating fluidized bed of 125 mm diameter and 1800 mm height. Olive cake is a waste from olive oil production. A lignite coal that is most widely used in Turkey (Tuncbilek lignite) was used together with OC and the combustion characteristics of olive cake (OC)+coal mixture were investigated. The combustion experiments were carried out with various excess air ratios. The excess air ratio, {lambda} has been changed between 1.1 and 2.16. Temperature distribution along the bed was measured with thermocouples. On-line concentrations of O{sub 2}, SO{sub 2}, CO{sub 2}, CO, NOx and total hydrocarbons were measured in the flue gas. Various runs were conducted with each mixture of OC and lignite, namely 25, 50 and 75 wt% OC mixed with lignite. These mixtures were burned with various excess air ratios. Combustion efficiencies of olive cake and lignite coal mixtures are calculated, and the optimum conditions for operating parameters are discussed. There is a sharp decrease observed in the combustion losses due to hydrocarbons and CO as the excess air ratio increases. The minimum emissions are observed at about {lambda} = 1.5. The combustion efficiency for lignite coal changes between 82 and 98% for various excess air ratios used in the study. The results suggest that OC is good fuel that can be mixed with lignite coal for cleaner energy production in small-scale industries by using CFB. Less than 50 wt% OC concentration in the fuel mixture is suggested in order to be within the EU limits for emissions. 11 refs., 12 figs., 7 tabs.

  8. Snow hydrology in a general circulation model

    Science.gov (United States)

    Marshall, Susan; Roads, John O.; Glatzmaier, Gary

    1994-01-01

    A snow hydrology has been implemented in an atmospheric general circulation model (GCM). The snow hydrology consists of parameterizations of snowfall and snow cover fraction, a prognostic calculation of snow temperature, and a model of the snow mass and hydrologic budgets. Previously, only snow albedo had been included by a specified snow line. A 3-year GCM simulation with this now more complete surface hydrology is compared to a previous GCM control run with the specified snow line, as well as with observations. In particular, the authors discuss comparisons of the atmospheric and surface hydrologic budgets and the surface energy budget for U.S. and Canadian areas. The new snow hydrology changes the annual cycle of the surface moisture and energy budgets in the model. There is a noticeable shift in the runoff maximum from winter in the control run to spring in the snow hydrology run. A substantial amount of GCM winter precipitation is now stored in the seasonal snowpack. Snow cover also acts as an important insulating layer between the atmosphere and the ground. Wintertime soil temperatures are much higher in the snow hydrology experiment than in the control experiment. Seasonal snow cover is important for dampening large fluctuations in GCM continental skin temperature during the Northern Hemisphere winter. Snow depths and snow extent show good agreement with observations over North America. The geographic distribution of maximum depths is not as well simulated by the model due, in part, to the coarse resolution of the model. The patterns of runoff are qualitatively and quantitatively similar to observed patterns of streamflow averaged over the continental United States. The seasonal cycles of precipitation and evaporation are also reasonably well simulated by the model, although their magnitudes are larger than is observed. This is due, in part, to a cold bias in this model, which results in a dry model atmosphere and enhances the hydrologic cycle everywhere.

  9. The Role of Eddy-Tansport in the Thermohaline Circulation

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Paola Cessi

    2011-11-17

    Several research themes were developed during the course of this project. (1) Low-frequency oceanic varibility; (2) The role of eddies in the Antarctic Circumpolar Current (ACC) region; (3) Deep stratification and the overturning circulation. The key findings were as follows: (1) The stratification below the main thermocline (at about 500m) is determined in the circumpolar region and then communicated to the enclosed portions of the oceans through the overturning circulation. (2) An Atlantic pole-to-pole overturning circulation can be maintained with very small interior mixing as long as surface buoyancy values are shared between the northern North Atlantic and the ACC region.

  10. Ocean circulation: its effects on seasonal sea-ice simulations.

    Science.gov (United States)

    Hibler, W D; Bryan, K

    1984-05-04

    A diagnostic ice-ocean model of the Arctic, Greenland, and Norwegian seas is constructed and used to examine the role of ocean circulation in seasonal sea-ice simulations. The model includes lateral ice motion and three-dimensional ocean circulation. The ocean portion of the model is weakly forced by observed temperature and salinity data. Simulation results show that including modeled ocean circulation in seasonal sea-ice simulations substantially improves the predicted ice drift and ice margin location. Simulations that do not include lateral ocean movment predict a much less realistic ice edge.

  11. Parametric study on a natural circulation cooled U-battery

    Energy Technology Data Exchange (ETDEWEB)

    De Zwaan, Sieuwert; Kloosterman, Jan Leen [Delft University of Technology, Delft (Netherlands); Van Uitert, Gert [The Hague (Netherlands)

    2008-07-01

    A feasibility study has been performed on a natural circulation cooled small nuclear reactor with a molten salt or tin as a coolant. This reactor is called the U-Battery. The study included neutronics calculations to obtain the minimum dimensions required for a critical system during burnup, the calculation of coolant temperature and core temperature reactivity coefficients, and an investigation of the thermal hydraulics to asses the possibilities for natural circulation cooling. For every coolant, core designs are feasible within the dimensions imposed and with natural circulation of the coolant. (authors)

  12. A new barotropic model of the wind-driven circulation

    Institute of Scientific and Technical Information of China (English)

    张庆华; 曲媛媛; 李坚克

    1999-01-01

    Rationalized by the observational circulation pattern in the upper ocean of the North Pacific, meridional friction term is first incorporated in a barotropic theoretical model of the wind-driven circulation. The governing potential vortieity equation thence has β term and wind stress curl term (the two of the Sverdrup balance), zonal friction term and meridional friction term. The analytical solution satisfactorily captures many important features of the wind-driven circulation in the North Pacific: Kuroshio, Oyashio, Kuroshio extension, North Equatorial Current, and especially the eastern boundary currents in the North Pacific, i.e. California current and Alaska current.

  13. Manual for THOR-AirPAS - air pollution assessment system

    DEFF Research Database (Denmark)

    Jensen, Steen Solvang; Ketzel, Matthias; Brandt, Jørgen

    The report provides an outline of the THOR-AirPAS - air pollution assessment system and a brief manual for getting started with the air quality models and input data included in THOR-AirPAS.......The report provides an outline of the THOR-AirPAS - air pollution assessment system and a brief manual for getting started with the air quality models and input data included in THOR-AirPAS....

  14. The gyre-scale circulation of the North Atlantic and sea level at Brest

    Directory of Open Access Journals (Sweden)

    P. L. Woodworth

    2010-02-01

    Full Text Available The relationship between the gyre-scale circulation of the North Atlantic, represented by air pressure near to the centre of the sub-tropical gyre, and sea level measured at the eastern boundary of the ocean has been investigated using records commencing in the middle of the 18th century. These time series are twice as long as those employed in an earlier study of this relationship. Near-continuous values of annual mean sea level and mean high water from Brest, and air pressure fields for the eastern North Atlantic derived from terrestrial instrumental pressure records and ship logbook information, have been used to demonstrate that sea level on the eastern boundary does indeed appear to be related to air pressure at the centre of the gyre (subject to reservations concerning short sub-sections of data near to the ends of the records. These findings confirm the earlier conclusions but over much longer timescales. This relationship can explain at least part of the century timescale accelerations in European sea level records obtained from tide gauge and saltmarsh data. This finding has important implications for interpretation of the observed sea level rise and acceleration on the European Atlantic coast, suggesting that redistribution of water could play an important role instead of (or as well as change in ocean volume.

  15. Gas Hold-Up, Mixing Time and Circulation Time in Internal Loop Airlift Bubble Column

    Directory of Open Access Journals (Sweden)

    Ali Abdul Rahman–Al Ezzi

    2014-01-01

    Full Text Available The effects of superficial gas in the riser (Vgr and liquid phase properties on the gas hold-up(ɛg , mixing time (Tm and circulation time (TC were studied in 8 liter internal air lift loop reactor (down comer-to-riser crosssectional area ratio = 0.249. Air was used as a gas phase. Water and four aqueous solutions of 10% concentration methanol, ethanol, (were used to simulate the behavior of non-coalescing organic liquids 50% glycerol and 2% Carboxy Methyl Cellulose (CMC were used to simulate the behavior of coalescing viscous liquids. Polyethylene-non-porous-solid particles with a concentration of (50 Kg/m3 were used as solid phase. Superficial gas velocity varied from 0.01 m/s to 0.1 m/s and air dispersed into the center of the draught tube by using a porous gas distributor. The results showed that (εg increased with increasing gas velocity and coalescence inhibition of liquid, while Tm and Tc decrease with increasing gas velocity. It was found that increasing liquid viscosity and coalescence reduces (εg but increases (Tm and (Tc. The gas holdup was correlated with dimensionless groups and independent parameter with correlation coefficient is 0.967, the following correlation is obtained.

  16. Air Conditioning Does Reduce Air Pollution Indoors

    Science.gov (United States)

    Healy, Bud

    1970-01-01

    Report of the winter meeting of the American Society of Heating, Refrigerating and Air-Conditioning Engineers. Subjects covered are--(1) title subject, (2) predictions for the human habitat in 1994, (3) fans, and (4) fire safety in buildings. (JW)

  17. Winter Season Stratospheric Circulation in the SAMIL/LASG General Circulation Model

    Institute of Scientific and Technical Information of China (English)

    REN Rongcai; WU Guoxiong; Ming CAI; YU Jingjing

    2009-01-01

    In this paper, we examine the performance of the 26-level version of the SAMIL/LASG GCM (R42/L26)in simulating the seasonal cycle and perpetual winter mean stratospheric circulation as well as its variability by comparing them with the NCEP/NCAR reanalysis. The results show that the model is capable of reproducing many key features of the climatology and seasonal variation of the stratospheric circulation despite that the model's mean polar vortex is stronger and more zonally symmetric compared to the observation. Further diagnosis of the results from a perpetual-January-run of the SAMIL/LASG GCM indicates that the dominant winter-season oscillation mode in the model's stratosphere exhibits a similar inter-seasonal timescale with similar spatial patterns as those inferred from the NCEP/NCAR reanalysis. In particular, the simulated polar vortex oscillation mode exhibits a dominant inter-seasonal timescale of about 120 days, and is accompanied with the simultaneous poleward and downward propagation of temperature anomalies in the stratosphere and the equatorward propagation of temperature anomalies in the troposphere. More encouragingly, the 26-layer version of the SAMIL/LASG GCM is able to produce three strong Stratospheric Sudden Warming events during the 1825 days of perpetual-January integration, with the polar westerly jet completely reversed for a few weeks without imposing any prescribed anomalous forcing at the lower boundary.

  18. Air-Sea Interactions over Lakes on Titan

    Science.gov (United States)

    Soto, Alejandro; Rafkin, Scot C. R.

    2016-10-01

    The exchange of methane between the atmosphere and surface liquid reservoirs dominates the short time-scale methanological cycle. In this study, previous two-dimensional simulations of the exchange of methane vapor, sensible heat and momentum between the atmosphere and lakes are updated with the inclusion of radiative forcing, three dimensions, and realistic coastlines. Titan's air-sea exchange in two dimensions indicated that the exchange process was self-limiting. Evaporation from lakes produced a shallow but extremely stable marine layer that suppressed turbulent exchange. Furthermore, the circulation associated with the higher buoyancy of methane-rich atmosphere over the lake was offset by the oppositely directed thermal sea breeze circulation, which muted the mean wind. Two major weaknesses of this previous work were the lack of radiative forcing and the imposition of two dimensionality, which limited the full range of dynamical solutions. Based on early theoretical studies, it was thought that magnitude of turbulent energy flux exchanges would be much larger than radiative fluxes, thereby justifying the neglect of radiation, but the two-dimensional simulations indicated that this was not a valid assumption. The dynamical limitations of two-dimensional simulations are well known. Vorticity stretching (i.e., circulation intensification through vertical motion) is not possible and it is also not possible to produce dynamically balanced gradient wind-type circulations. As well, the irregular shape of a realistic coastline cannot be expressed in two dimensions, and these realistic structures will generally induce complex convergence and divergence circulations in the atmosphere. The impact of radiative forcing and the addition of the third dimension on the air-sea exchange are presented.

  19. Experimental Study on an On-Line Measurement of High Temperature Circulating Ash Flux in a Circulating Fluidized Bed Boiler

    Institute of Scientific and Technical Information of China (English)

    Lu Xiaofeng; Li Yourong

    2001-01-01

    A new kind of measuring method that may be used to measure high temperature circulating solid particles flux in a circulating fluidized bed boiler is studied in this paper. The measuring method is founded on the principle of thermal equilibrium. A series of cold tests and hot tests were carried to optimize the structure and collocation of water-cooling tubes and showed that the method had the advantage of simple, accurate, reliable and good applicability for on-line usage in a circulating fluidized bed boiler.

  20. Diagnostic technologies for circulating tumour cells and exosomes.

    Science.gov (United States)

    Shao, Huilin; Chung, Jaehoon; Issadore, David

    2015-11-24

    Circulating tumour cells (CTCs) and exosomes are promising circulating biomarkers. They exist in easily accessible blood and carry large diversity of molecular information. As such, they can be easily and repeatedly obtained for minimally invasive cancer diagnosis and monitoring. Because of their intrinsic differences in counts, size and molecular contents, CTCs and exosomes pose unique sets of technical challenges for clinical translation-CTCs are rare whereas exosomes are small. Novel technologies are underway to overcome these specific challenges to fully harness the clinical potential of these circulating biomarkers. Herein, we will overview the characteristics of CTCs and exosomes as valuable circulating biomarkers and their associated technical challenges for clinical adaptation. Specifically, we will describe emerging technologies that have been developed to address these technical obstacles and the unique clinical opportunities enabled by technological innovations.

  1. Study on Circulation and Management of Rural Land Use Right

    Institute of Scientific and Technical Information of China (English)

    Wanjiang WANG

    2015-01-01

    Currently,agriculture and rural economy have entered a new development stage. According to market demands and comparative advantages of regional resources,strategic adjustment of agricultural structure and realizing transformation from traditional agriculture to modern agriculture have become primary tasks. Land is the essential element of agricultural production,making innovation upon rural land use system and establishing flexible and effective land circulation system concern efficiency and optimization of agricultural resource allocation and development of rural element market. With more and more farmers engaged in secondary and tertiary industries,land left by those farmers is circulated to those farmers willing to do farming. Rural land circulation is inevitable trend of economic and social development,but it is a progressive process. To realize smooth rural land circulation,there must be standardized system.

  2. Circulation and geostrophic transport in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, D.P.; Murty, V.S.N.

    Utilising the hydrographic data collected during the early northeast monsoon of 1983 and southwest monsoon of 1984, the circulation of waters of the Bay of Bengal and the associated volume transport have been studied in the upper 1000 m...

  3. Circulating mesenchymal stem cells and their clinical implications

    Directory of Open Access Journals (Sweden)

    Liangliang Xu

    2014-01-01

    Full Text Available Circulating mesenchymal stem cells (MSCs is a new cell source for tissue regeneration and tissue engineering. The characteristics of circulating MSCs are similar to those of bone marrow-derived MSCs (BM-MSCs, but they exist at a very low level in healthy individuals. It has been demonstrated that MSCs are able to migrate to the sites of injury and that they have some distinct genetic profiles compared to BM-MSCs. The current review summaries the basic knowledge of circulating MSCs and their potential clinical applications, such as mobilizing the BM-MSCs into circulation for therapy. The application of MSCs to cure a broad spectrum of diseases is promising, such as spinal cord injury, cardiovascular repair, bone and cartilage repair. The current review also discusses the issues of using of allogeneic MSCs for clinical therapy.

  4. Improvement of uniformity in cultivation environment and crop growth rate by hybrid control of air flow devices

    Institute of Scientific and Technical Information of China (English)

    BAEK Min-Seon; KWON Sook-Youn; LIM Jae-Hyun

    2015-01-01

    A complete control type plant factory has high efficiency in terms of cultivation area by constructing vertical multiple layered cultivation beds. However, it has a problem of irregular crop growth due to temperature deviation at upper and lower beds and increases in energy consumption by a prolonged cultivation period. In this work, air flow rate inside a facility was improved by a hybrid control of air flow devices like air conditioning and air circulation fan with an established wireless sensor network to minimize temperature deviations between upper and lower beds and to promote crop growth. The performance of proposed system was verified with an experimental environment or Case A wherein air conditioning device was operated without a control algorithm and Case B wherein air conditioning and circulation fans were alternatively operated based on the hybrid control algorithm. After planting leafy vegetables under each experimental condition, crops were cultivated for 21 days. As a result, Case B wherein AC (air conditioning) and ACF (air-circulation fan) were alternatively operated based on the hybrid control algorithm showed that fresh mass, number of leaves, and leaf length for the crops grown were increased by 40.6%, 41.1%, and 11.1%, respectively, compared to Case A.

  5. Air filtration in HVAC systems

    CERN Document Server

    Ginestet, Alain; Tronville, Paolo; Hyttinen, Marko

    2010-01-01

    Air filtration Guidebook will help the designer and user to understand the background and criteria for air filtration, how to select air filters and avoid problems associated with hygienic and other conditions at operation of air filters. The selection of air filters is based on external conditions such as levels of existing pollutants, indoor air quality and energy efficiency requirements.

  6. Fructose ingestion acutely stimulates circulating FGF21 levels in humans

    OpenAIRE

    Dushay, Jody R.; Toschi, Elena; Mitten, Emilie K.; Fisher, ffolliott M.; Herman, Mark A.; Maratos-Flier, Eleftheria

    2014-01-01

    Objective Fibroblast growth factor 21 (FGF21) is a hormone with pleiotropic metabolic activities which, in rodents, is robustly regulated by fasting and ketogenic diets. In contrast, similar dietary interventions have either no or minimal effects on circulating FGF21 in humans. Moreover, no intervention or dietary challenge has been shown to acutely stimulate circulating FGF21 in either humans or animals. Recent animal data suggest that the transcription factor Carbohydrate Responsive-Element...

  7. [Fetal circulation in normal pregnancy and in placental insufficiency].

    Science.gov (United States)

    Ivanov, B; Malinova, M

    2010-01-01

    The fetal circulation is different from the adult circulation. One of the quite common conditions that are challenging to the developing fetus is placental hypoxia. Regardless of its cause, placental vascular insufficiency is commonly assumed to be an important factor in the development of intrauterine growth retardation. Several mechanisms are involved in the fetal adaptation to the decompensation during hypoxemia. Doppler Ultrasound technologies can help to evaluate of the fetal wellbeing.

  8. Poleward Expansion of the Hadley Circulation in CMIP5 Simulations

    Institute of Scientific and Technical Information of China (English)

    HU Yongyun; TAO Lijun; LIU Jiping

    2013-01-01

    Observational analyses have demonstrated that the Hadley circulation has expanded poleward in recent decades.Important issues are what caused the widening of the Hadley circulation and whether the observed widening is related to anthropogenic forcing.In the present study,we use currently available simulations of the Coupled Model Intercomparison Project Phase-5 (CMIP5) to analyze changes in the width of the Hadley circulation.It is found that CMIP5 historical simulations with greenhouse gas (GHG) forcing generate a total widening of ~0.15°±0.06° in latitude (10 yr)-1 for the period 1979-2005,and the widening in CMIP5 historical simulations with all forcings is ~0.17° ± 0.06° per decade.Similar to that in CMIP3,the simulated poleward expansion in CMIP5 is much weaker than the observational reanalyses.In CMIP5 projection simulations for the 21st century,magnitudes of widening of the Hadley circulation increase with radiative forcing.For the extreme projected radiative forcing of RCP8.5,the total annual-mean widening of the Hadley circulation is ~ 0.27° ± 0.04° (10 yr)-1 in the 21st century.Although CMIP5 underestimates observed poleward expansion of the Hadley circulation,the results of this study suggest that the observed trends in the width of the Hadley circulation are caused by anthropogenic forcing and that increasing GHGs play an important role in the observed poleward expansion of the Hadley circulation,in addition to other forcings emphasized in previous studies.

  9. Flow boiling heat transfer in circulating fluidized bed

    Institute of Scientific and Technical Information of China (English)

    Xiaoguang REN; Jiangdong ZHENG; Sefiane KHELLII; Arumemi-Ikhide MICHAEL

    2009-01-01

    In order to enhance heat transfer and mitigate contamination in the boiling processes, a new type of vapor-liquid-solid (3-phase) circulating fluidized bed boil-ing system has been designed, combining a circulating fluidized bed with boiling heat transfer. Experimental results show an enhancement of the boiling curve. Flow visualization studies concerning flow hydrodynamics within the riser column are also conducted whose results are presented and discussed.

  10. Computation of the q -th roots of circulant matrices

    Directory of Open Access Journals (Sweden)

    Pakizeh Mohammadi Khanghah

    2014-05-01

    Full Text Available In this paper‎, ‎we investigate the reduced form of circulant matrices‎ ‎and we show that the problem of computing the $q$-th roots of a‎ ‎nonsingular circulant matrix $A$ can be reduced to that of computing‎ ‎the $q$-th roots of two half size matrices $B-C$ and $B+C$. 

  11. Twentieth century Walker Circulation change: data analysis and model experiments

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Qingjia [Leibniz-Institut fuer Meereswissenschaften, Kiel (Germany); Chinese Research Academy of Environmental Sciences, River and Coastal Environment Research Center, Beijing (China); Chinese Academy of Sciences, Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Qingdao (China); Latif, Mojib; Park, Wonsun; Keenlyside, Noel S.; Martin, Thomas [Leibniz-Institut fuer Meereswissenschaften, Kiel (Germany); Semenov, Vladimir A. [Leibniz-Institut fuer Meereswissenschaften, Kiel (Germany); A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, Moscow (Russian Federation)

    2012-05-15

    Recent studies indicate a weakening of the Walker Circulation during the twentieth century. Here, we present evidence from an atmospheric general circulation model (AGCM) forced by the history of observed sea surface temperature (SST) that the Walker Circulation may have intensified rather than weakened. Observed Equatorial Indo-Pacific Sector SST since 1870 exhibited a zonally asymmetric evolution: While the eastern part of the Equatorial Pacific showed only a weak warming, or even cooling in one SST dataset, the western part and the Equatorial Indian Ocean exhibited a rather strong warming. This has resulted in an increase of the SST gradient between the Maritime Continent and the eastern part of the Equatorial Pacific, one driving force of the Walker Circulation. The ensemble experiments with the AGCM, with and without time-varying external forcing, suggest that the enhancement of the SST gradient drove an anomalous atmospheric circulation, with an enhancement of both Walker and Hadley Circulation. Anomalously strong precipitation is simulated over the Indian Ocean and anomalously weak precipitation over the western Pacific, with corresponding changes in the surface wind pattern. Some sensitivity to the forcing SST, however, is noticed. The analysis of twentieth century integrations with global climate models driven with observed radiative forcing obtained from the Coupled Model Intercomparison Project (CMIP) database support the link between the SST gradient and Walker Circulation strength. Furthermore, control integrations with the CMIP models indicate the existence of strong internal variability on centennial timescales. The results suggest that a radiatively forced signal in the Walker Circulation during the twentieth century may have been too weak to be detectable. (orig.)

  12. Effects of Variations in East Asian Snow Cover on Modulating Atmospheric Circulation over the North Pacific Ocean.

    Science.gov (United States)

    Clark, Martyn P.; Serreze, Mark C.

    2000-10-01

    At least four different modeling studies indicate that variability in snow cover over Asia may modulate atmospheric circulation over the North Pacific Ocean during winter. Here, satellite data on snow extent for east Asia for 1971-95 along with atmospheric fields from the National Centers for Environmental Prediction-National Center for Atmospheric Research reanalysis are used to examine whether the circulation signals seen in model results are actually observed in nature. Anomalies in snow extent over east Asia exhibit a distinct lack of persistence. This suggests that understanding the effects of east Asian snow cover is more germane for short- to medium-range weather forecasting applications than for problems on longer timescales. While it is impossible to attribute cause and effect in the empirical study, analyses of composite fields demonstrate relationships between snow cover extremes and atmospheric circulation downstream remarkably similar to those identified in model results. Positive snow cover extremes in midwinter are associated with a small decrease in air temperatures over the transient snow regions, a stronger east Asian jet, and negative geopotential height anomalies over the North Pacific Ocean. Opposing responses are observed for negative snow cover extremes. Diagnosis of storm track feedbacks shows that the action of high-frequency eddies does not reinforce circulation anomalies in positive snow cover extremes. However, in negative snow cover extremes, there are significant decreases in high-frequency eddy activity over the central North Pacific Ocean, and a corresponding decrease in the mean cyclonic effect of these eddies on the geopotential tendency, contributing to observed positive height anomalies over the North Pacific Ocean. The circulation signals over the North Pacific Ocean are much more pronounced in midwinter (January-February) than in the transitional seasons (November-December and March-April).

  13. Primary Reasoning behind the Double ITCZ Phenomenon in a Coupled Ocean-Atmosphere General Circulation Model

    Institute of Scientific and Technical Information of China (English)

    李江龙; 张学洪; 俞永强; 戴福山

    2004-01-01

    This paper investigates the processes behind the double ITCZ phenomenon, a common problem in Coupled ocean-atmosphere General Circulation Models (CGCMs), using a CGCM-FGCM-0 (Flexible General Circulation Model, version 0). The double ITCZ mode develops rapidly during the first two years of the integration and becomes a perennial phenomenon afterwards in the model. By way of Singular Value Decomposition (SVD) for SST, sea surface pressure, and sea surface wind, some air-sea interactions are analyzed. These interactions prompt the anomalous signals that appear at the beginning of the coupling to develop rapidly. There are two possible reasons, proved by sensitivity experiments: (1) the overestimated east-west gradient of SST in the equatorial Pacific in the ocean spin-up process, and (2) the underestimated amount of low-level stratus over the Peruvian coast in CCM3 (the Community Climate Model, Version Three). The overestimated east-west gradient of SST brings the anomalous equatorial easterly. The anomalous easterly, affected by the Coriolis force in the Southern Hemisphere, turns into an anomalous westerly in a broad area south of the equator and is enhanced by atmospheric anomalous circulation due to the underestimated amount of low-level stratus over the Peruvian coast simulated by CCM3. The anomalous westerly leads to anomalous warm advection that makes the SST warm in the southeast Pacific.The double ITCZ phenomenon in the CGCM is a result of a series of nonlocal and nonlinear adjustment processes in the coupled system, which can be traced to the uncoupled models, oceanic component, and atmospheric component. The zonal gradient of the equatorial SST is too large in the ocean component and the amount of low-level stratus over the Peruvian coast is too low in the atmosphere component.

  14. Real-driving emissions of circulating Spanish car fleet in 2015 using RSD Technology.

    Science.gov (United States)

    Pujadas, M; Domínguez-Sáez, A; De la Fuente, J

    2017-01-15

    In this paper we present the results corresponding to on-road traffic emissions measurements obtained during two field campaigns developed in the Madrid region (Spain) during 2014 and 2015 in the framework of the CORETRA project. The experimental strategy was based on the use of a RSD 4600 remote sensor in interurban roads. These measurements have produced a global database of >190,000 vehicles with their associated emission data (NO/CO2, HC/CO2 and CO/CO2), which can be considered representative of the current Spanish circulating fleet. The results of M1 vehicles were analysed according to their distribution by Euro Standard and engine model. One of the relevant findings is that, despite the progressive introduction of increasingly stringent standards, no NO emission reduction is observed for diesel vehicles with time, although this behavior shows significative differences among brands and engine models. We have also investigated the presence of "high emitter" (HE) vehicles in the Spanish M1 circulating fleet and most of the HE detected corresponded to diesel vehicles with very high NO/CO2 values. With these results at hand, we strongly propose the future incorporation of the "high emitter vehicle" definition into the European environmental legislation, as well as the establishment of specific strategies in each country/region in order to identify these anomalous vehicles. Identification and repair of HE vehicles within the European circulating fleets, although are not easy tasks, should be considered very important for the improvement of air quality in the EU. The use of non-intrusive optical technologies (i.e. RSD) is an excellent option to provide instantaneous real emission data of each individual vehicle without disturbing traffic and for on-road fleet monitoring. In summary, it is a good strategy to obtain valuable information about the long term surveillance of real vehicle emission trends, specially after the introduction of new standard.

  15. Modelling the Seasonal Overturning Circulation in the Red Sea

    KAUST Repository

    Yao, Fengchao

    2015-04-01

    The overturning circulation in the Red Sea exhibits a distinct seasonally reversing pattern and is studied using 50-year, high-resolution MIT general circulation model simulations. The seasonal water exchange in the Strait of Bab el Mandeb is successfully simulated, and the structures of the intruding subsurface Gulf of Aden intermediate water are in good agreement with summer observations in 2011. The model results suggest that the summer overturning circulation is driven by the combined effect of the shoaling of the thermocline in the Gulf of Aden resulting from remote winds in the Arabian Sea and an upward surface slope from the Red Sea to the Gulf of Aden set up by local surface winds in the Red Sea. For the winter overturning circulation, the climatological model mean results suggest that the surface inflow intensifies in a western boundary current in the southern Red Sea that switches to an eastern boundary current north of 24°N. The overturning is accomplished through a cyclonic recirculation and a cross-basin overturning circulation in the northern Red Sea, with major sinking occurring along a narrow band of width about 20 km along the eastern boundary and weaker upwelling along the western boundary. The northward pressure gradient force, strong vertical mixing, and horizontal mixing near the boundary are the essential dynamical components in the model\\'s winter overturning circulation.

  16. Distance spectra and Distance energy of Integral Circulant Graphs

    CERN Document Server

    c, Aleksandar Ili\\'

    2011-01-01

    The distance energy of a graph $G$ is a recently developed energy-type invariant, defined as the sum of absolute values of the eigenvalues of the distance matrix of $G$. There was a vast research for the pairs and families of non-cospectral graphs having equal distance energy, and most of these constructions were based on the join of graphs. A graph is called circulant if it is Cayley graph on the circulant group, i.e. its adjacency matrix is circulant. A graph is called integral if all eigenvalues of its adjacency matrix are integers. Integral circulant graphs play an important role in modeling quantum spin networks supporting the perfect state transfer. In this paper, we characterize the distance spectra of integral circulant graphs and prove that these graphs have integral eigenvalues of distance matrix $D$. Furthermore, we calculate the distance spectra and distance energy of unitary Cayley graphs. In conclusion, we present two families of pairs $(G_1, G_2)$ of integral circulant graphs with equal distanc...

  17. Cooling Performance of Natural Circulation for a Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Park, Suki; Chun, J. H.; Yum, S. B. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    This paper deals with the core cooling performance by natural circulation during normal operation and a flow channel blockage event in an open tank-in-pool type research reactor. The cooling performance is predicted by using the RELAP5/ MOD3.3 code. The core decay heat is usually removed by natural circulation to the reactor pool water in open tank-in-pool type research reactors with the thermal power less than several megawatts. Therefore, these reactors have generally no active core cooling system against a loss of normal forced flow. In reactors with the thermal power less than around one megawatt, the reactor core can be cooled down by natural circulation even during normal full power operation. The cooling performance of natural circulation in an open tank-in-pool type research reactor has been investigated during the normal natural circulation and a flow channel blockage event. It is found that the maximum powers without void generation at the hot channel are around 1.16 MW and 820 kW, respectively, for the normal natural circulation and the flow channel blockage event.

  18. Minor effect of meltwater on the ocean circulation during deglaciation

    Directory of Open Access Journals (Sweden)

    G. Lohmann

    2012-08-01

    Full Text Available Decaying Northern Hemisphere ice sheets during deglaciation affect the high latitude hydrological balance in the North Atlantic and therefore the ocean circulation after the Last Glacial Maximum. Surprisingly, geological data suggest that meltwater fluxes of about 14–20 m sea-level equivalent flushed into the North Atlantic without significantly influencing the Atlantic meridional overturning circulation. Using a three-dimensional ocean circulation model coupled to an energy balance model of the atmosphere, we investigate the response of the ocean circulation to spatio-temporal variable deglacial freshwater discharges. Freshwater inputs are simulated by a three-dimensional thermo-mechanical ice sheet model of the Northern Hemisphere. In our experiments, we find a strong sensitivity of the ocean circulation when the deglacial meltwater is injected into the surface layers yielding a quasi shut-down. On the other hand, the parameterization of huge sub-glacial outbursts as so-called hyperpycnal flows are mimicked through bottom injections in ocean models leading to a reduced sensitivity of the overturning circulation against freshwater perturbations and providing a consistent representation of the deglacial climate evolution.

  19. An efficiency booster for energy conversion in natural circulation loops

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dongqing, E-mail: wangdongqing@stu.xjtu.edu.cn [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Beijing Computational Science Research Center, Beijing 100084 (China); Jiang, Jin, E-mail: jjiang@eng.uwo.ca [Department of Electrical and Computer Engineering, The University of Western Ontario, London, Ontario N6A 5B9 (Canada); Beijing Computational Science Research Center, Beijing 100084 (China)

    2016-08-01

    Highlights: • Low driving power conversion efficiency of natural circulation loops is proved. • The low conversion efficiency leads to low heat transfer capacity of such loops. • An efficiency booster is designed with turbine to increase the efficiency. • Performance of the proposed booster has been numerically simulated. • The booster drastically enhances heat transfer capacity of such loops. - Abstract: In this paper, the capacity of a natural circulation loop for transferring heat from a heat source to a heat sink has been analyzed. It is concluded that the capacity of the natural circulation loop depends on the conversion efficiency of the thermal energy from the heat source to the driving force for the circulation of the flow. The low conversion efficiency leading to weak driving force in such loops has been demonstrated analytically and validated through simulation results. This issue has resulted in a low heat transfer capacity in the circulation loop. To increase the heat transfer capacity, one has to improve this efficiency. To meet such a need, a novel efficiency booster has been developed in this paper. The booster essentially increases the flow driving force and hence significantly improves the overall heat transfer capacity. Design and analysis of this booster have been performed in detail. The performance has been examined through extensive computer simulations. It is concluded that the booster can indeed drastically improve the heat transfer capacity of the natural circulation loop.

  20. A Circulation Index for the Himalayan Mountain Arc: Reconciling Conflicting Signals of Climate Change Along the Third Pole"

    Science.gov (United States)

    Fowler, H. J.; Forsythe, N. D.; Blenkinsop, S.

    2014-12-01

    Rivers of high mountain Asia are of tremendous importance for livelihoods and well-being of hundreds of millions of people [1]. Independent of climate change the population of the Indus basin will experience water scarcity due to demographic pressures [2]. Recent geophysical research focusing on the Karakoram has revealed patterns of change in both climate [3,4] and cryosphere [5,6] which diverge from the trajectories expected in a globally warming climate. Additional studies have underlined the influence of large-scale atmospheric circulation on glacier mass balance status [7,8]. This study identifies and quantifies a regional feature of atmospheric circulation, the latitudinal position of the westerly jet "immediately upstream" of the Karakoram, which has substantial influence of surface air temperature variability across the Himalayan Mountain Arc and adjacent Indo-Gangetic plains. Characteristics of this feature, and its correlation to local air temperatures, are compared amongst an ensemble of meteorological reanalyses: ERA-40, ERA-Interim, NCEP CFSR, NASA MERRA and JRA-55. Correlations between the westerly jet position and local observations indicate a strong causal mechanism of short term near surface air temperature variability. Furthermore, the Karakoram and NW UIB respond differently during the Summer season to this circulation mode than both the plains of the lower Indus as well as the Central and Eastern Himalaya. This differentiated response provides a plausible explanation for differences in summer temperature trends along the Himalayan arc and by substantiating differences in melt season energy inputs provides a clear climatic mechanism to explain the "Karakoram anomaly." [1] DOI:10.1126/science.330.6004.585-a [2] DOI:10.5194/hess-14-1669-2010 [3] DOI:10.1175/JCLI3860.1 [4] DOI:10.3354/cr00957 [5] DOI:10.1038/ngeo1450 [6] DOI:10.1038/nature11324 [7] DOI:10.1038/nclimate1580 [8] DOI:10.1038/nclimate2055

  1. Air Mass Origin in the Arctic and its Response to Future Warming

    Science.gov (United States)

    Orbe, Clara; Newman, Paul A.; Waugh, Darryn W.; Holzer, Mark; Oman, Luke; Polvani, Lorenzo M.; Li, Feng

    2014-01-01

    We present the first climatology of air mass origin in the Arctic in terms of rigorously defined air mass fractions that partition air according to where it last contacted the planetary boundary layer (PBL). Results from a present-day climate integration of the GEOSCCM general circulation model reveal that the Arctic lower troposphere below 700 mb is dominated year round by air whose last PBL contact occurred poleward of 60degN, (Arctic air, or air of Arctic origin). By comparison, approx. 63% of the Arctic troposphere above 700 mb originates in the NH midlatitude PBL, (midlatitude air). Although seasonal changes in the total fraction of midlatitude air are small, there are dramatic changes in where that air last contacted the PBL, especially above 700 mb. Specifically, during winter air in the Arctic originates preferentially over the oceans, approx. 26% in the East Pacific, and approx. 20% in the Atlantic PBL. By comparison, during summer air in the Arctic last contacted the midlatitude PBL primarily over land, overwhelmingly so in Asia (approx. 40 %) and, to a lesser extent, in North America (approx. 24%). Seasonal changes in air-mass origin are interpreted in terms of seasonal variations in the large-scale ventilation of the midlatitude boundary layer and lower troposphere, namely changes in the midlatitude tropospheric jet and associated transient eddies during winter and large scale convective motions over midlatitudes during summer.

  2. [Magnetic field numerical calculation and analysis for magnetic coupling of centrifugal blood pump for extracorporeal circulation].

    Science.gov (United States)

    Hu, Zhaoyan; Lu, Lijun; Zhang, Tianyi; Chen, Zhenglong; Zhang, Tao

    2013-12-01

    This paper mainly studies the driving system of centrifugal blood pump for extracorporeal circulation, with the core being disc magnetic coupling. Structure parameters of disc magnetic coupling are related to the ability of transferring magnetic torque. Therefore, it is necessary to carry out disc magnetic coupling permanent magnet pole number (n), air gap length (L(g)), permanent magnet thickness (L(m)), permanent magnet body inside diameter (R(i)) and outside diameter (R(o)), etc. thoroughly. This paper adopts the three-dimensional static magnetic field edge element method of Ansys for numerical calculation, and analyses the relations of magnetic coupling each parameter to transmission magnetic torque. It provides a good theory basis and calculation method for further optimization of the disc magnetic coupling.

  3. Relationship of surface O3 to large-scale circulation patterns during two recent winters

    Science.gov (United States)

    Mao, Huiting; Talbot, Robert

    2004-03-01

    We demonstrate a direct connection between large-scale circulation patterns and surface O3 using atmospheric observations obtained during winters 2002 and 2003. Measurements at two rural sites in the northeastern U.S. revealed that median mixing ratios of O3 in winter 2003 were increased by up to 80% compared to 2002, and greatly exceeded previous spring annual maximums. To explain this we propose that strong meridional flows in winter 2003 frequently transported O3-rich mid-tropospheric air masses from high latitudes to the northeastern U.S. while cooling regional climate 4.4°C below normal. Our measurements also show that an exceptionally elevated spring O3 maximum occurred in 2003. The impact from this winter enhancement on the levels of O3 and other species during the following months will be largely driven by actual climatic conditions.

  4. Characteristics modeling for supercritical circulating fluidized bed boiler working in oxy-combustion technology

    Science.gov (United States)

    Balicki, Adrian; Bartela, Łukasz

    2014-06-01

    Among the technologies which allow to reduce greenhouse gas emission, mainly carbon dioxide, special attention deserves the idea of `zeroemission' technology based on boilers working in oxy-combustion technology. In the paper the results of analyses of the influence of changing two quantities, namely oxygen share in oxidant produced in the air separation unit, and oxygen share in oxidant supplied to the furnace chamber on the selected characteristics of a steam boiler including the degree of exhaust gas recirculation, boiler efficiency and adiabatic flame temperature, was examined. Due to the possibility of the integration of boiler model with carbon dioxide capture, separation and storage installation, the subject of the analysis was also to determine composition of the flue gas at the outlet of a moisture condensation installation. Required calculations were made using a model of a supercritical circulating fluidized bed boiler working in oxy-combustion technology, which was built in a commercial software and in-house codes.

  5. Synthesis gas production using oxygen storage materials as oxygen carrier over circulating fluidized bed

    Institute of Scientific and Technical Information of China (English)

    DAI Xiaoping; YU Changchun; LI Ranjia; WU Qiong; HAO Zhengping

    2008-01-01

    A novel process for synthesis gas production over Circulating Fluidized Bed (CFB) using oxygen storage materials as oxygen carrier was reported. First, oxygen in the air was chemically fixed and converted to lattice oxygen of oxygen storage materials over regenerator, and then methane was selectively oxidized to synthesis gas with lattice oxygen of oxygen storage materials over riser reactor. The results from simulation reaction of CFB by sequential redox reaction on a fixed bed reactor using lanthanum-based perovskite LaFeO3 and La0.8Sr0.2Fe0.9Co0.1O3 oxides prepared by sol-gel, suggested that the depleted oxygen species could be regenerated, and methane could be oxidized to synthesis gas by lattice oxygen with high selectivity. The partial oxidation of methane to synthesis gas over CFB using lattice oxygen of the oxygen storage materials instead of gaseous oxygen should be possibly applicable.

  6. Relations between atmospheric circulation and mass balance of South Cascade Glacier, Washington, USA

    Science.gov (United States)

    McCabe, G.J.; Fountain, A.G.

    1995-01-01

    The yearly net mass balance of South Cascade Glacier, Washington, has decreased since the mid-1970s. Resuls show that the decrease is primarily caused by a significant decrease in the winter mass balance. Changes in atmospheric circulation indicate a decrease in the movement of storms and moisture from the Pacific Ocean into the western contiguous United States. In addition, the increase in winter mean 700-mb heights over western Canada and the northern western contiguous United States indicates an increase in subsidence, which results in a warming and drying of the air that further reduces precipitation and also increases the ratio of rain to snow during the cold season. These factors contribute to below-average winter mass balances. -from Authors

  7. Development of pressurized internally circulating fluidized bed combustion technology; Kaatsu naibu junkan ryudosho boiler no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Ishihara, I. [Center for Coal Utilization, Japan, Tokyo (Japan); Nagato, S.; Toyoda, S. [Ebara Corp., Tokyo (Japan)

    1996-09-01

    The paper introduced support research on element technology needed for the design of hot models of the pressurized internally circulating fluidized bed combustion boiler in fiscal 1995 and specifications for testing facilities of 4MWt hot models after finishing the basic plan. The support research was conduced as follows: (a) In the test for analysis of cold model fluidization, it was confirmed that each characteristic value of hot models is higher than the target value. Further, calculation parameters required for computer simulation were measured and data on the design of air diffusion nozzle for 1 chamber wind box were sampled. (b) In the CWP conveyance characteristic survey, it was confirmed that it is possible to produce CWP having favorable properties. It was also confirmed that favorable conveyability can be maintained even if the piping size was reduced down to 25A. (c) In the gas pressure reducing test, basic data required for the design of gas pressure reducing equipment were sampled. Specifications for the fluidized bed combustion boiler of hot models are as follows: evaporation amount: 3070kg/h, steam pressure: 1.77MPa, fuel supply amount: 600kg-coal/h, boiler body: cylinder shape water tube internally circulating fluidized bed combustion boiler. 4 refs., 4 figs.

  8. Time-varying changes in the simulated structure of the Brewer-Dobson Circulation

    Science.gov (United States)

    Garfinkel, Chaim I.; Aquila, Valentina; Waugh, Darryn W.; Oman, Luke D.

    2017-01-01

    A series of simulations using the NASA Goddard Earth Observing System Chemistry Climate Model are analyzed in order to assess changes in the Brewer-Dobson Circulation (BDC) over the past 55 years. When trends are computed over the past 55 years, the BDC accelerates throughout the stratosphere, consistent with previous modeling results. However, over the second half of the simulations (i.e., since the late 1980s), the model simulates structural changes in the BDC as the temporal evolution of the BDC varies between regions in the stratosphere. In the mid-stratosphere in the midlatitude Northern Hemisphere, the BDC does not accelerate in the ensemble mean of our simulations despite increases in greenhouse gas concentrations and warming sea surface temperatures, and it even decelerates in one ensemble member. This deceleration is reminiscent of changes inferred from satellite instruments and in situ measurements. In contrast, the BDC in the lower stratosphere continues to accelerate. The main forcing agents for the recent slowdown in the mid-stratosphere appear to be declining ozone-depleting substance (ODS) concentrations and the timing of volcanic eruptions. Changes in both mean age of air and the tropical upwelling of the residual circulation indicate a lack of recent acceleration. We therefore clarify that the statement that is often made that climate models simulate a decreasing age throughout the stratosphere only applies over long time periods and is not necessarily the case for the past 25 years, when most tracer measurements were taken.

  9. Experimental Study on Gas—Solid Mass Transfer in Circulating Fluidized Beds.

    Institute of Scientific and Technical Information of China (English)

    WANGLinna; ZHANGLing; 等

    2002-01-01

    This study is devoted to gas-solid mass transfer behavior in heterogeneous two-phase flow. Experiments were carried out in a cold circulating fluidized bed of 3.0m in height and 72mm in diameter with naphthalene particles. Axial and radial distributions of sublimated naphthalene concentration in air were measured with an online concentration monitoring system HP GC-MS. Mass transfer coefficients were obtained under various operating condition, showing that heterogeneous flow structure strongly influences the axial and radial profiles of mass transfer coefficients. In the bottom dense region, mass transfer rate is high due to intensive dynamic behavior and higher relative slip velocity between gas and clusters. In the middle transition region and the upper diluter region, as a result of low mass transfer driving force and the influence of flow structure, mass transfer rate distribution becomes non-uniform. In conclusion, among the operating parameters influencing mass transfer coefficients, the superficial gas velocity is the most important factor and the solid circulation rate should be also taken into account.

  10. Arctic sea ice and atmospheric circulation under the abrupt4xCO2 scenario

    Institute of Scientific and Technical Information of China (English)

    YU Xiaoyong; Annette Rinke; JI Duoying; CUI Xuefeng; John C Moore

    2014-01-01

    We analyze sea ice changes from eight different earth system models that have conducted experiment abrupt4xCO2 of the Coupled Model Intercomparison Project Phase 5 (CMIP5). In response to abrupt quadrupling of CO2 from preindustrial levels, Arctic temperatures dramatically rise by about 10°C—16°C in winter and the seasonal sea ice cycle and sea ice concentration are signiifcantly changed compared with the pre-industrial control simulations (piControl). Changes of Arctic sea ice concentration are spatially correlated with temperature patterns in all seasons and highest in autumn. Changes in sea ice are associated with changes in atmospheric circulation patterns at heights up to the jet stream. While the pattern of sea level pressure changes is generally similar to the surface air temperature change pattern, the wintertime 500 hPa circulation displays a positive Paciifc North America (PNA) anomaly under abrupt4xCO2-piControl. This large scale teleconnection may contribute to, or feedback on, the simulated sea ice cover change and is associated with an intensiifcation of the jet stream over East Asia and the north Paciifc in winter.

  11. Simulation of NOx emission in circulating fluidized beds burning low-grade fuels

    Energy Technology Data Exchange (ETDEWEB)

    Afsin Gungor [Nigde University, Nigde (Turkey). Faculty of Engineering and Architecture

    2009-05-15

    Nitrogen oxides are a major environmental pollutant resulting from combustion. This paper presents a modeling study of pollutant NOx emission resulting from low-grade fuel combustion in a circulating fluidized bed. The simulation model accounts for the axial and radial distribution of NOx emission in a circulating fluidized bed (CFB). The model results are compared with and validated against experimental data both for small-size and industrial-size CFBs that use different types of low-grade fuels given in the literature. The present study proves that CFB combustion demonstrated by both experimental data and model predictions produces low and acceptable levels of NOx emissions resulting from the combustion of low-grade fuels. Developed model can also investigate the effects of different operational parameters on overall NOx emission. As a result of this investigation, both experimental data and model predictions show that NOx emission increases with the bed temperature but decreases with excess air if other parameters are kept unchanged. 37 refs., 5 figs., 5 tabs.

  12. CFD Analyses of Air-Ingress Accident for VHTRs

    Science.gov (United States)

    Ham, Tae Kyu

    The Very High Temperature Reactor (VHTR) is one of six proposed Generation-IV concepts for the next generation of nuclear powered plants. The VHTR is advantageous because it is able to operate at very high temperatures, thus producing highly efficient electrical generation and hydrogen production. A critical safety event of the VHTR is a loss-of-coolant accident. This accident is initiated, in its worst-case scenario, by a double-ended guillotine break of the cross vessel that connects the reactor vessel and the power conversion unit. Following the depressurization process, the air (i.e., the air and helium mixture) in the reactor cavity could enter the reactor core causing an air-ingress event. In the event of air-ingress into the reactor core, the high-temperature in-core graphite structures will chemically react with the air and could lose their structural integrity. We designed a 1/8th scaled-down test facility to develop an experimental database for studying the mechanisms involved in the air-ingress phenomenon. The current research focuses on the analysis of the air-ingress phenomenon using the computational fluid dynamics (CFD) tool ANSYS FLUENT for better understanding of the air-ingress phenomenon. The anticipated key steps in the air-ingress scenario for guillotine break of VHTR cross vessel are: 1) depressurization; 2) density-driven stratified flow; 3) local hot plenum natural circulation; 4) diffusion into the reactor core; and 5) global natural circulation. However, the OSU air-ingress test facility covers the time from depressurization to local hot plenum natural circulation. Prior to beginning the CFD simulations for the OSU air-ingress test facility, benchmark studies for the mechanisms which are related to the air-ingress accident, were performed to decide the appropriate physical models for the accident analysis. In addition, preliminary experiments were performed with a simplified 1/30th scaled down acrylic set-up to understand the air

  13. SOLID HOLDUP AND CIRCULATION RATE IN A LIQUID-SOLID CIRCULATING FLUIDIZED BED WITH VISCOUS LIQUID MEDIUM

    Directory of Open Access Journals (Sweden)

    N. Gnanasundaram

    2015-12-01

    Full Text Available Abstract Experiments were conducted in a liquid-solid circulating fluidized bed with different viscous liquids and particles to study the hydrodynamics, average solid hold up and solid circulation rate. The effects of operating parameters, i.e., primary liquid flow rate in the riser, auxiliary liquid flow rate, total liquid flow rate and viscosity of the liquid were studied for solids of different density and particle size. Results show that the circulating fluidization regime starts earlier for more viscous solutions because of the decrease in critical transitional velocity. The onset of solid holdup increases with an increase in liquid viscosity for sand and for glass beads. The solid circulation rate increases with an increase in total velocity and auxiliary velocity, and also increases with increasing viscosity.

  14. Ideas and perspectives: Southwestern tropical Atlantic coral growth response to atmospheric circulation changes induced by ozone depletion in Antarctica

    Science.gov (United States)

    Evangelista, Heitor; Wainer, Ilana; Sifeddine, Abdelfettah; Corrège, Thierry; Cordeiro, Renato C.; Lamounier, Saulo; Godiva, Daniely; Shen, Chuan-Chou; Le Cornec, Florence; Turcq, Bruno; Lazareth, Claire E.; Hu, Ching-Yi

    2016-04-01

    Recent Southern Hemisphere (SH) atmospheric circulation, predominantly driven by stratospheric ozone depletion over Antarctica, has caused changes in climate across the extratropics. Here, we present evidence that the Brazilian coast (southwestern Atlantic) may have been impacted from both wind and sea-surface temperature changes derived from this process. Skeleton analysis of massive coral species living in shallow waters off Brazil are very sensitive to air-sea interactions, and seem to record this impact. Growth rates of Brazilian corals show a trend reversal that fits the ozone depletion evolution, confirming that ozone impacts are far reaching and potentially affect coastal ecosystems in tropical environments.

  15. Carbon monoxide formation and emissions during waste incineration in a grate-circulating fluidized bed incinerator.

    Science.gov (United States)

    Yanguo Zhang; Qinghai Li; Aihong Meng; Changhe Chen

    2011-03-01

    This paper presents an experimental study of carbon monoxide (CO) formation and emissions in both grate drying bed incinerators and circulating fluidized bed (CFB) incinerators to simulate the two key parts of a combined grate and circulating fluidized bed (grate-CFB) incinerator in order to investigate pollutant emission control in municipal solid waste (MSW) combustion that occurs in a grate-CFB incinerator utilizing a patented technology. Polyvinyl chloride, polystyrene, kitchen waste, paper, textile, etc. were chosen to simulate the MSW. The effects of temperature, air staging, and moisture on the CO formation and emissions were analysed for both the grate drying bed combustion and the CFB combustion. In the grate drying bed, the low temperatures increased the carbon to CO conversion rate which also increased slightly with the moisture content. Industrial field tests in a commercial grate-CFB incinerator showed that the CO concentration at the grate drying bed exit was very high and decreased along furnace height. The carbon to CO conversion rates were 0-20% for the grate drying bed which exceeded the range of 0.8-16% measured in a grate drying bed exit of the commercial grate-CFB incinerator tests. In the commercial grate-CFB incinerator tests, at excess air ratios ranging from 1.5-2.0 or more, the CO emissions decreased to a low and stable level, whose corresponding carbon to CO conversion rates were far lower than 0-10%. The low CO emission is one of the factors enabling the polychlorinated dibenzodioxin/polychlorinated dibenzofuran emissions to satisfy the Chinese national regulations.

  16. Multidecadal changes in the relationship between extreme temperature events in Uruguay and the general atmospheric circulation

    Energy Technology Data Exchange (ETDEWEB)

    Renom, Madeleine; Barreiro, Marcelo [Universidad de la Republica, Unidad de Ciencias de la Atmosfera, Instituto de Fisica, Facultad de Ciencias, Montevideo (Uruguay); Rusticucci, Matilde [Universidad de Buenos Aires, Departamento de Ciencias de la Atmosfera y los Oceanos, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina)

    2011-12-15

    We analyze changes in the relationship between extreme temperature events and the large scale atmospheric circulation before and after the 1976 climate shift. To do so we first constructed a set of two temperature indices that describe the occurrence of warm nights (TN90) and cold nights (TN10) based on a long daily observed minimum temperature database that spans the period 1946-2005, and then divided the period into two subperiods of 30 years each (1946-1975 and 1976-2005). We focus on summer (TN10) and winter (TN90) seasons. During austral summer before 1976 the interannual variability of cold nights was characterized by a negative phase of the Southern Annular Mode (SAM) with a cyclonic anomaly centered off Uruguay that favoured the entrance of cold air from the south. After 1976 cold nights are associated not with the SAM, but with an isolated vortex at upper levels over South Eastern South America. During austral winter before 1976, the El Nino phenomenon dominated the interannual variability of warm nights through an increase in the northerly warm flow into Uruguay. However, after 1976 the El Nino connection weakened and the variability of warm nights is dominated by a barotropic anticyclonic anomaly located in the South Atlantic and a low pressure center over South America. This configuration also strengthens the northward flow of warm air into Uruguay. Our results suggest that changes in El Nino evolution after 1976 may have played a role in altering the relationship between temperature extreme events in Uruguay and the atmospheric circulation. (orig.)

  17. Electromagnetic circulation pump for corrosive gases; Pompe de circulation electromagnetique pour gaz corrosifs

    Energy Technology Data Exchange (ETDEWEB)

    Noe, P.; Delafosse, D.; Deletre, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    In order to transport very corrosive products (fluorinated compounds) we have been led to develop a totally metallic circulation pump capable of operating at above room temperatures and with a molecular vacuum. We have aimed at maximum simplicity both in its conception and in its operation. The tests showed that the compression ratios produced, although not high are interesting (1.5 at a pressure of 100 torr) (see curve I). The flow-rate range is very wide: about one hundred ccs/atm/min. to 3000 ccs/atm/min. (see curves IV, V, VI). The desorption of this pump presents no difficulty if both the aspiration and the reject sides are pumped together. A hole of 2 mm diameter drilled in the piston makes it possible to desorb the space between the two segments. The price of this pump is not high: 1300 F, with the electrical cabinet. (authors) [French] En vue de vehiculer des produits tres corrosifs (composes fluores) nous avons ete amene a realiser une pompe de circulation entierement metallique, capable de fonctionner en temperature et sous vide moleculaire. Nous avons recherche la simplicite tant dans sa realisation que dans son fonctionnement. Les essais ont montre que les taux de compression fournis, sans etre eleves, sont interessants (1,5 a la pression de 100 torr) (voir courbe I). La gamme des debits est tres large: d'une centaine de cm{sup 3}/atm/mn a 3000 cm{sup 3}/atm/mn (voir courbes IV, V, VI). La desorption de cette pompe ne presente pas de difficulte en pompant a la fois cote aspiration et cote refoulement. Un percage de 2 mm de diametre dans le piston permet la desorption de l'espace entre les 2 segments. Le cout de cette pompe est peu eleve: 1300 F, coffret electrique compris. (auteurs)

  18. 走近Air

    Institute of Scientific and Technical Information of China (English)

    马华

    2007-01-01

    @@ 大家对air这个单词并不陌生,它通常用作名词,表示"空气".例如: 1.Better let in fresh air. 最好让新鲜空气进来. 2.The air smells of paint. 空气里散发着油漆味. 3.The air was heavy with perfume of the flowers. 空气里弥漫着花朵的芳香.

  19. Contact air abrasion.

    Science.gov (United States)

    Porth, R

    1999-05-01

    The advantages of contact air abrasion techniques are readily apparent. The first, of course, is the greatly increased ease of use. Working with contact also tends to speed the learning curve by giving the process a more natural dental feel. In addition, as one becomes familiar with working with a dust stream, the potential for misdirecting the air flow is decreased. The future use of air abrasion for deep decay removal will make this the treatment of choice for the next millennium.

  20. Olefin metathesis in air.

    Science.gov (United States)

    Piola, Lorenzo; Nahra, Fady; Nolan, Steven P

    2015-01-01

    Since the discovery and now widespread use of olefin metathesis, the evolution of metathesis catalysts towards air stability has become an area of significant interest. In this fascinating area of study, beginning with early systems making use of high oxidation state early transition metal centers that required strict exclusion of water and air, advances have been made to render catalysts more stable and yet more functional group tolerant. This review summarizes the major developments concerning catalytic systems directed towards water and air tolerance.

  1. [Anesthesia during video-assisted thoracoscopic lobectomy using laryngeal ductwork and auxiliary mechanical ventilation].

    Science.gov (United States)

    Porkhanov, V A; Polyakov, I S; Danilov, V V; Kononenko, V B; Zhikharev, V A

    2016-01-01

    The article presents the experience of video-assisted thoracoscopic lobectomies in patients without endotracheal intubation and sparing of spontaneous breathing. The results of intraoperative monitoring and laboratory data of all perioperative period are described. In view of these data it was concluded that such approach can decline the severity of stress-response against surgical aggression in this group of patients.

  2. The measured performance of an air thermosyphon system

    Science.gov (United States)

    Marshall, L. S.; Burns, P. J.; Winn, C. B.

    Results of performance tests of a solar thermosyphon test cell are reported. The test cell comprised a structure on a concrete slab with fiberglass insulated walls. The north wall consisted of a styrofoam-insulated gravel-filled box, while the south wall featured double glazing over metal solar collectors. The ceiling was ducted to provide air flow from the south collector to the rock storage, and an air channel was built into the floor. A numerical model was developed of the expected performance of the cell, using an Euler technique to solve the transient energy and momentum equations. The temperature was monitored at various points of the structure and flow visualization studies were made with titanium tetrachloride. Heat was found to be stored in the upper portion of the rock box, which because of its size also inhibited circulation. Thermal comfort was determined to be available due to warm surfaces, rather than warm air.

  3. Biogeography in the air: fungal diversity over land and oceans

    Directory of Open Access Journals (Sweden)

    J. Fröhlich-Nowoisky

    2012-03-01

    Full Text Available Biogenic aerosols are relevant for the Earth system, climate, and public health on local, regional, and global scales. Up to now, however, little is known about the diversity and biogeography of airborne microorganisms. We present the first DNA-based analysis of airborne fungi on global scales, showing pronounced geographic patterns and boundaries. In particular we find that the ratio of species richness between Basidiomycota and Ascomycota is much higher in continental air than in marine air. This may be an important difference between the "blue ocean" and "green ocean" regimes in the formation of clouds and precipitation, for which fungal spores can act as nuclei. Our findings also suggest that air flow patterns and the global atmospheric circulation are important for the understanding of global changes in biodiversity.

  4. Biogeography in the air: fungal diversity over land and oceans

    Directory of Open Access Journals (Sweden)

    J. Fröhlich-Nowoisky

    2011-07-01

    Full Text Available Biogenic aerosols are relevant for the Earth system, climate, and public health on local, regional, and global scales. Up to now, however, little is known about the diversity and biogeography of airborne microorganisms. We present the first DNA-based analysis of airborne fungi on global scales, showing pronounced geographic patterns and boundaries. In particular we found that the ratio of species richness between Basidiomycota and Ascomycota is much higher in continental air than in marine air. This may be an important difference between the "blue ocean" and "green ocean" regimes in the formation of clouds and precipitation, for which fungal spores can act as nuclei. Our findings also suggest that air flow patterns and the global atmospheric circulation are important for the evolution of microbial ecology and for the understanding of global changes in biodiversity.

  5. Transfair. An air method of floor heating and cooling; Transfair. Procede de chauffage et de rafraichissement par le sol a air

    Energy Technology Data Exchange (ETDEWEB)

    Desvouas, C. [Tarnsfair TTR, 77 - Perthes en Gatinais (France)

    1997-12-31

    This paper presents the `Transfair` method which consists in the use of air instead of water in heating and cooling systems. This presentation comprises 4 parts. Part 1 is a general presentation of the activities of the French TTR company which has developed the Transfair method and its realizations in industrial space heating and in chemical industry (refrigeration units for sulfuric acid). Part 2 is a comparative evaluation of equivalent water and air systems in order to emphasize the advantages of air cooling systems (simplicity and reliability). Part 3 is a presentation of a software for the optimization of the dimensioning of components and investment costs of industrial air space heating systems. Part 4 is a presentation of the feasibility study of a floor cooled by air circulation and with a self-balancing of circuits confirmed by flow rate measurements. (J.S.)

  6. DEFORMATION OF MOISTURE FLUX CIRCULATION SURROUNDING THE LANDFALL TYPHOON "BILIS"

    Institute of Scientific and Technical Information of China (English)

    RAN Ling-kun; YANG Wen-xia; HONG Yan-chao

    2009-01-01

    The deformation parameter (DP), which is defined as the product of shear deformation and stretching deformation of moisture flux circulation, is introduced. The tendency equation of DP is derived in pressure coordinates. Furthermore, DP is used to diagnose the deformation character of moisture flux circulation in the periphery of Bilis. The analysis showed that before Bilis landed, DP presented eight abnormal areas, which distributed alternately and closely encircled the low-pressure center. This indicated that the moisture flux circulation in the periphery of Bilis rotated counterclockwise and stretched longitudinally and latitudinally to deform. After Bilis landed, DP weakened gradually and its regular pattern of horizontal distribution loosened. The shear and stretching deformations of moisture flux circulation surrounding Bilis weakened after the typhoon landed. The deformation of moisture flux circulation in the periphery of Bilis mainly appeared in the middle-lower troposphere. There existed 1/2 phase difference between the shear and stretching deformations in the vertical-latitudinal cross section and a π/4 phase difference between them on the horizontal plane. As Bilis landed and further moved inland of China, the intensities of DP, shear and stretching deformations decreased, meanwhile their vertical and horizontal structures became irregular. The chief dynamic factors responsible for the deformation of moisture flux circulation in the periphery of Bilis were the three terms associated with the three-dimensional advection transportation of DP, square difference between shear and stretching deformations coupling with Coriolis parameter, and horizontal gradient of geopotential height before Bilis landed. The last two dynamic factors impacted jointly on the deformation of moisture flux circulation after Bilis landed.

  7. Characterization of quantum circulant networks having perfect state transfer

    Science.gov (United States)

    Bašić, Milan

    2013-01-01

    In this paper we answer the question of when circulant quantum spin networks with nearest-neighbor couplings can give perfect state transfer. The network is described by a circulant graph G, which is characterized by its circulant adjacency matrix A. Formally, we say that there exists a perfect state transfer (PST) between vertices {a,bin V(G)} if | F( τ) ab | = 1, for some positive real number τ, where F( t) = exp(i At). Saxena et al. (Int J Quantum Inf 5:417-430, 2007) proved that | F( τ) aa | = 1 for some {ain V(G)} and {tauin {R}^+} if and only if all eigenvalues of G are integer (that is, the graph is integral). The integral circulant graph ICG n ( D) has the vertex set Z n = {0, 1, 2, . . . , n - 1} and vertices a and b are adjacent if {gcd(a-b,n)in D} , where {D subseteq {d : d mid n, 1 ≤ d < n}} . These graphs are highly symmetric and have important applications in chemical graph theory. We show that ICG n ( D) has PST if and only if {nin 4{N}} and {D=widetilde{D_3} \\cup D_2\\cup 2D_2\\cup 4D_2|cup {n/2^a}} , where {widetilde{D_3}={din D | n/din 8{N}}, D_2= {din D | n/din 8{N}+4}{setminus}{n/4}} and {ain{1,2}} . We have thus answered the question of complete characterization of perfect state transfer in integral circulant graphs raised in Angeles-Canul et al. (Quantum Inf Comput 10(3&4):0325-0342, 2010). Furthermore, we also calculate perfect quantum communication distance (distance between vertices where PST occurs) and describe the spectra of integral circulant graphs having PST. We conclude by giving a closed form expression calculating the number of integral circulant graphs of a given order having PST.

  8. Direct Push Groundwater Circulation Wells for Remediation of BTEX and Volatile Organics

    Energy Technology Data Exchange (ETDEWEB)

    Borden, R.C.; Cherry, R.S.

    2000-09-30

    Direct push groundwater circulation wells (DP-GCW) are a promising technology for remediation of groundwater contaminated with dissolved hydrocarbons and chlorinated solvents. In these wells, groundwater is withdrawn from the formation at the bottom of the well, aerated and vapor stripped and injected back into the formation at or above the water table. Previous field studies have shown that: (a) GCWs can circulate significant volumes of groundwater; and (b) GCWs can effectively remove volatile compounds and add oxygen. In this work, we describe the development and field-testing of a system of DP-GCWs for remediation of volatile organics such as benzene, toluene, ethylbenzene, and toluene (BTEX). The GCWs were constructed with No. 20 slotted well screen (2.4 cm ID) and natural sand pack extending from 1.5 to 8.2 m below grade. Air is introduced {approximately}7.5 m below grade via 0.6 cm tubing. Approximately 15% of the vertical length of the air supply tubing is wrapped in tangled mesh polypropylene geonet drainage fabric to provide surface area for biological growth and precipitation of oxidized iron. These materials were selected to allow rapid installation of the GCWs using 3.8 cm direct push Geoprobe{reg_sign} rods, greatly reducing well installation costs. Laboratory testing of these sparged wells and computational fluid dynamics (CFD) modeling showed that these wells, although they used only about 1 L/min of air, could circulate about 1 L/min of water through the surrounding aquifer. This flow was sufficient to capture all of a flowing contaminant if the wells are sufficiently closely together, about 1 meter on center depending on the air flow rate supplied, in a line across the plume. The CFD work showed the details of this ability to capture, and also showed that unforeseen heterogeneities in the aquifer such as a gradient of permeability or a thin impermeable layer (such as a clay layer) did not prevent the system from working largely as intended. The

  9. Direct Push Groundwater Circulation Wells for Remediation of BTEX and Volatile Organics

    Energy Technology Data Exchange (ETDEWEB)

    Borden, R. E.; Cherry, Robert Stephen

    2000-09-01

    Direct push groundwater circulation wells (DP-GCW) are a promising technology for remediation of groundwater contaminated with dissolved hydrocarbons and chlorinated solvents. In these wells, groundwater is withdrawn from the formation at the bottom of the well, aerated and vapor stripped and injected back into the formation at or above the water table. Previous field studies have shown that: (a) GCWs can circulate significant volumes of groundwater; and (b) GCWs can effectively remove volatile compounds and add oxygen. In this work, we describe the development and field-testing of a system of DP-GCWs for remediation of volatile organics such as benzene, toluene, ethylbenzene, and toluene (BTEX). The GCWs were constructed with No. 20 slotted well screen (2.4 cm ID) and natural sand pack extending from 1.5 to 8.2 m below grade. Air is introduced ~7.5 m below grade via 0.6 cm tubing. Approximately 15% of the vertical length of the air supply tubing is wrapped in tangled mesh polypropylene geonet drainage fabric to provide surface area for biological growth and precipitation of oxidized iron. These materials were selected to allow rapid installation of the GCWs using 3.8 cm direct push Geoprobe® rods, greatly reducing well installation costs. Laboratory testing of these sparged wells and computational fluid dynamics (CFD) modeling showed that these wells, although they used only about 1 L/min of air, could circulate about 1 L/min of water through the surrounding aquifer. This flow was sufficient to capture all of a flowing contaminant if the wells are sufficiently closely together, about 1 meter on center depending on the air flow rate supplied, in a line across the plume. The CFD work showed the details of this ability to capture, and also showed that unforeseen heterogeneities in the aquifer such as a gradient of permeability or a thin impermeable layer (such as a clay layer) did not prevent the system from working largely as intended. The system was tested in a

  10. Challenges and Opportunities of Air Quality Management in Mexico City

    Science.gov (United States)

    Paramo, V.

    2013-05-01

    The Mexico City Metropolitan Area (MCMA) is located in the central plateau of Mexico and is the capital of the country. Its natural characteristics present favorable conditions for air pollution formation and accumulation: mountains surrounding the city, frequent thermal inversions, high isolation all around the year and weak winds. To these natural conditions, a population of more than 20 million inhabitants, a fleet of 4.5 million vehicles and more than 4 thousands industries, make air quality management a real challenge for governments of the region. Intensive air quality improvement actions and programs began at the end of the 1980's and continued nowadays. Since then criteria air pollutants concentrations have decreased in such a way that currently most of pollutants meet the Mexican air quality standards, except for ozone and particulate matter. Applied measures comprised of fuel quality improvements, fuel replacements, regulations for combustion processes, closing of high polluting refineries and industries, regulations of emissions for new and on road vehicles, mandatory I/M programs for vehicles, circulation restrictions for vehicles (Day without car program), alert program for elevated air pollution episodes, improvement of public transportation, among others. Recent researches (MILAGRO 2006 campaign) found that currently it is necessary to implement emissions reduction actions for Volatile Organic Compounds, particulate matter with a diameter of less than 2.5 micrometers PM2.5 and Nitrogen Oxides, in order to reduce concentrations of ozone and fine particulate matter. Among the new measures to be implemented are: regulations for VOCs emissions in the industry and commercial sectors; regulation of the diesel fleet that includes fleets renewal, filters and particulate traps for in use vehicles and regulation of the cargo fleet; new schemes for reducing the number of vehicles circulating in the city; implementation of non-motorized mobility programs; among

  11. Analysis of a natural draught tower in the circulation seawater system of nuclear power plant of Laguna Verde; Analisis de una torre de tiro natural en el sistema de agua de circulacion de mar de la central nucleoelectrica Laguna Verde

    Energy Technology Data Exchange (ETDEWEB)

    Tijerina S, F.; Vargas A, A. [Comision Federal de Electricidad, Central Nucleoelectrica Laguna Verde, Subgerencia de Ingenieria, Carretera Veracruz-Medellin Km. 7.5, Veracruz (Mexico)], e-mail: francisco.tijerina@cfe.gob.mx

    2009-10-15

    The analysis of a natural draught tower in open circuit for the cooling system of seawater circulation on the nuclear power plant of Laguna Verde, it is based on conditions of 2027 MWt and 2317 MWt, where the flows of circulation water system hardly vary and whose purpose will be, to cool the seawater circulation. The circulation water system is used as heat drain in main condenser of turbo generator to condense the nuclear vapor. The annual average temperature in the seawater at present is of 26 C to the entrance to circulation water system and it is vary in accordance with the time of year. The mean temperature of leaving of circulation water system to the sea is of 41 C. Having a cooling tower to reduce the entrance temperature to the circulation water system, it improves the efficiency of thermal transfer in condenser, it improves the vacuum in condenser giving more operative margin to avoid condenser losses by air entrances and nuclear power plant shutdowns, as well as for to improve the efficiency of operative balance of nuclear power plant, also it prevents the impact in thermal transfer efficiency in condenser by the climatic change. (Author)

  12. Bifurcations of a creeping air-water flow in a conical container

    Science.gov (United States)

    Balci, Adnan; Brøns, Morten; Herrada, Miguel A.; Shtern, Vladimir N.

    2016-10-01

    This numerical study describes the eddy emergence and transformations in a slow steady axisymmetric air-water flow, driven by a rotating top disk in a vertical conical container. As water height Hw and cone half-angle β vary, numerous flow metamorphoses occur. They are investigated for β =30°, 45°, and 60°. For small Hw, the air flow is multi-cellular with clockwise meridional circulation near the disk. The air flow becomes one cellular as Hw exceeds a threshold depending on β . For all β , the water flow has an unbounded number of eddies whose size and strength diminish as the cone apex is approached. As the water level becomes close to the disk, the outmost water eddy with clockwise meridional circulation expands, reaches the interface, and induces a thin layer with anticlockwise circulation in the air. Then this layer expands and occupies the entire air domain. The physical reasons for the flow transformations are provided. The results are of fundamental interest and can be relevant for aerial bioreactors.

  13. A probabilistic method of calculating circulation-induced trends

    Science.gov (United States)

    Brox Nilsen, Irene; Stagge, James Howard; Merete Tallaksen, Lena

    2015-04-01

    The water cycle in Europe has changed substantially over the past three decades. Increasing runoff is observed during winter and at northern latitudes in particular. Spring and summer months, as well as southern latitudes, are facing drier conditions. To understand what is driving large-scale changes in runoff, we look into changes in precipitation and temperature and link these to changes in atmospheric circulation. Previous studies have used the method of trend ratios (Cahynová and Huth, 2009) to attribute precipitation and temperature trends to changes in the frequency of circulation types. A trend ratio is the ratio of hypothetical trend, i.e., the trend that would result due to changes in circulation type frequency only, to the observed trend. However, the method of trend ratios has two drawbacks. First, if the observed trend is small, division by a very low value results in a meaningless trend ratio and thus requires a cut-off value to keep the trend ratio within meaningful boundaries. Second, the method does not allow a comparison of the observed trend to the spread of possible outcomes, because the method of hypothetical trends is based on a deterministic model. We propose a new, more robust method for detecting the importance of circulation-induced changes in explaining the observed trends, which has the benefit of being a non-parametric statistical test that assesses the entire range of hypothetical trends. Instead of creating a hypothetical series by replacing the observation on a given day with the long-term climatic mean of a certain month and circulation type (as in the existing trend ratio method), the new approach replaces the observation on a given day with a random sample from the distribution of the variable for the given month and circulation type. The method introduces the possibility to assign a rejection rate, thus allowing statistical significance to be assessed. We apply the method on time series of precipitation and temperature from the

  14. Prediction of circulation control performance characteristics for Super STOL and STOL applications

    Science.gov (United States)

    Naqvi, Messam Abbas

    The rapid air travel growth during the last three decades, has resulted in runway congestion at major airports. The current airports infrastructure will not be able to support the rapid growth trends expected in the next decade. Changes or upgrades in infrastructure alone would not be able to satisfy the growth requirements, and new airplane concepts such as the NASA proposed Super Short Takeoff and Landing and Extremely Short Takeoff & Landing (ESTOL) are being vigorously pursued. Aircraft noise pollution during Takeoff & Landing is another serious concern and efforts are aimed to reduce the airframe noise produced by Conventional High Lift Devices during Takeoff & Landing. Circulation control technology has the prospect of being a good alternative to resolve both the aforesaid issues. Circulation control airfoils are not only capable of producing very high values of lift (Cl values in excess of 8.0) at zero degree angle of attack, but also eliminate the noise generated by the conventional high lift devices and their associated weight penalty as well as their complex operation and storage. This will ensure not only satisfying the small takeoff and landing distances, but minimal acoustic signature in accordance with FAA requirements. The Circulation Control relies on the tendency of an emanating wall jet to independently control the circulation and lift on an airfoil. Unlike, conventional airfoil where rear stagnation point is located at the sharp trailing edge, circulation control airfoils possess a round trailing edge, therefore the rear stagnation point is free to move. The location of rear stagnation point is controlled by the blown jet momentum. This provides a secondary control in the form of jet momentum with which the lift generated can be controlled rather the only available control of incidence (angle of attack) in case of conventional airfoils. The use of Circulation control despite its promising potential has been limited only to research applications

  15. Glacial ocean circulation and stratification explained by reduced atmospheric temperature

    Science.gov (United States)

    Jansen, Malte F.

    2017-01-01

    Earth’s climate has undergone dramatic shifts between glacial and interglacial time periods, with high-latitude temperature changes on the order of 5–10 °C. These climatic shifts have been associated with major rearrangements in the deep ocean circulation and stratification, which have likely played an important role in the observed atmospheric carbon dioxide swings by affecting the partitioning of carbon between the atmosphere and the ocean. The mechanisms by which the deep ocean circulation changed, however, are still unclear and represent a major challenge to our understanding of glacial climates. This study shows that various inferred changes in the deep ocean circulation and stratification between glacial and interglacial climates can be interpreted as a direct consequence of atmospheric temperature differences. Colder atmospheric temperatures lead to increased sea ice cover and formation rate around Antarctica. The associated enhanced brine rejection leads to a strongly increased deep ocean stratification, consistent with high abyssal salinities inferred for the last glacial maximum. The increased stratification goes together with a weakening and shoaling of the interhemispheric overturning circulation, again consistent with proxy evidence for the last glacial. The shallower interhemispheric overturning circulation makes room for slowly moving water of Antarctic origin, which explains the observed middepth radiocarbon age maximum and may play an important role in ocean carbon storage.

  16. Static slot testing of conventional lost circulation materials

    Energy Technology Data Exchange (ETDEWEB)

    Hinkebein, T.E.; Behr, V.L.; Wilde, S.L.

    1983-01-01

    A study of the utility of conventional lost circulation materials and testing methods was performed using a modified API slot tester. Five lost circulation materials were evaluated in 266 tests at both room temperature and temperature-aged conditions simulating expected geothermal environments. A large variation in the maximum pressure (or sealing pressure) the plug could withstand was attributed to nonrepeatability in plug strengths. Plugs were composed to multiple or single particle bridges, with the latter providing stronger, better sealing plugs. Seals occurred on the upstream surface of the slots in all cases. Sealing pressures generally decreased with increasing slot widths and decreasing solids concentration. When the slot width was less than the size of the largest rigid particle in the lost circulation slurry, sealing pressure was maximized. When the slot width was greater than three times the maximum rigid particle size, no significant sealing ability was observed with the conventional materials tested. Additionally, cellulosic lost circulation materials are severely degraded by temperature aging. Mud gellation provided no significant improvement in lost circulation material sealing ability.

  17. PWR hot leg natural circulation modeling with MELCOR code

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae Hong; Lee, Jong In [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of)

    1997-12-31

    Previous MELCOR and SCDAP/RELAP5 nodalizations for simulating the counter-current, natural circulation behavior of vapor flow within the RCS hot legs and SG U-tubes when core damage progress can not be applied to the steady state and water-filled conditions during the initial period of accident progression because of the artificially high loss coefficients in the hot legs and SG U-tubes which were chosen from results of COMMIX calculation and the Westinghouse natural circulation experiments in a 1/7-scale facility for simulating steam natural circulation behavior in the vessel and circulation modeling which can be used both for the liquid flow condition at steady state and for the vapor flow condition at the later period of in-vessel core damage. For this, the drag forces resulting from the momentum exchange effects between the two vapor streams in the hot leg was modeled as a pressure drop by pump model. This hot leg natural circulation modeling of MELCOR was able to reproduce similar mass flow rates with those predicted by previous models. 6 refs., 2 figs. (Author)

  18. Mixing and dissipation in a geostrophic buoyancy-driven circulation

    Science.gov (United States)

    Vreugdenhil, Catherine A.; Gayen, Bishakhdatta; Griffiths, Ross W.

    2016-08-01

    Turbulent mixing and energy dissipation have important roles in the global circulation but are not resolved by ocean models. We use direct numerical simulations of a geostrophic circulation, resolving turbulence and convection, to examine the rates of dissipation and mixing. As a starting point, we focus on circulation in a rotating rectangular basin forced by a surface temperature difference but no wind stress. Emphasis is on the geostrophic regime for the horizontal circulation, but also on the case of strong buoyancy forcing (large Rayleigh number), which implies a turbulent convective boundary layer. The computed results are consistent with existing scaling theory that predicts dynamics and heat transport dependent on the relative thicknesses of thermal and Ekman boundary layers, hence on the relative roles of buoyancy and rotation. Scaling theory is extended to describe the volume-integrated rate of mixing, which is proportional to heat transport and decreases with increasing rotation rate or decreasing temperature difference. In contrast, viscous dissipation depends crucially on whether the thermal boundary layer is laminar or turbulent, with no direct Coriolis effect on the turbulence unless rotation is extremely strong. For strong forcing, in the geostrophic regime, the mechanical energy input from buoyancy goes primarily into mixing rather than dissipation. For a buoyancy-driven circulation in a basin comparable to the North Atlantic we estimate that the total rate of mixing accounts for over 95% of the mechanical energy supply, implying that buoyancy is an efficient driver of mixing in the oceans.

  19. Self-biased circulators for high power applications

    Science.gov (United States)

    Sokolov, Alexander S.

    Self-biased circulators exploit the properties of high anisotropy magnetic field in hexagonal ferrites, thus allowing operation without biasing magnets and a significant size and weight reduction. Although first self-biased circulators were demonstrated more than 20 years ago, all the prototypes constructed so far are unsuitable for practical applications. An attempt to design a self-biased circulator from scratch was made. Novel exceptionally low dielectric loss and high heat conductivity ceramic materials were developed and innovative substrate synthesis techniques were employed. Low temperature cofiring of green body ferrite compacts and dielectric ceramic slurries were mastered, resulting in solid composite substrates. Original device design was developed. Key features (including wide coupling angles, wide microstriplines, thick substrate, and absence of impedance transformers) enable low insertion loss, broadband operation, high power handling, and compact size. Fabrication and testing of Ka band Y-junction self-biased circulator are reported herein. Furthermore, design approach and fabrication techniques developed here can be readily applied for the construction of X-band self-biased circulators, provided that suitable ferrite materials are available. Low temperature cofiring of ferrite and dielectric materials is especially beneficial for various RF and high-frequency applications. Multiple devices can be readily fabricated on a single wafer using conventional lithographic techniques, resulting in true microwave monolithic integrated circuit.

  20. Composite circulation index of weather extremes (the example for Poland

    Directory of Open Access Journals (Sweden)

    Zbigniew Ustrnul

    2013-10-01

    Full Text Available The paper describes the implementation of a composite circulation index of weather extremes (CIE. The new index informs about the synoptic conditions favoring the occurrence of extremes on a regional scale. It was evaluated for temperature and precipitation extremes for Poland. Daily homogenized data obtained from 14 weather stations, which cover most of the country, were used. The data used cover the 60-year period from 1951 to 2010. The index is based on relationships between extremes and mesoscale circulation conditions. The core material also included data describing circulation types for the study period. Three different calendars were used (Grosswetterlagen, by Lity?ski, by Nied?wied?. The conditional probability of the occurrence of extremes for particular types was calculated independently using partial indices (Partial Index of weather Extremes ? PIE. The higher the index values, the more favorable the synoptic situation for the occurrence of extremes. The results were grouped by describing the probability of temperature and precipitation extremes on the IPCC likelihood scale. Three thresholds corresponding to the frequency of an occurrence were identified via a seasonal approach. The CIE was validated using basic correlation coefficients as well as contingency tables based on feature-displacement criteria and Bayesian Probability Methods. The results confirmed the significance of atmospheric circulation in the formation of temperature and precipitation extremes in Poland. The CIE proved the relationship by trying to estimate the probability of temperature and precipitation extremes occurrence depending on the circulation type forecasted.

  1. Seasonal variability in the Central Mediterranean Sea circulation

    Directory of Open Access Journals (Sweden)

    R. Sorgente

    Full Text Available A high resolution eddy-resolving primitive equation numerical model, based on the Princeton Ocean Model (POM, is used to study the seasonal variability of the general circulation in the Central Mediterranean Sea. The model is run on a seasonal cycle, perpetual year simulation for five years, with nesting to the coarser resolution Ocean General Circulation Model (OGCM, covering the whole Mediterranean Sea. The model results are compared to the current knowledge on the hydrography and dynamics of the area, with a special focus on the annual cycle of the Modified Atlantic Water (MAW, on the circulation in the Sardinia Channel, the water exchange across the Strait of Sicily, and on the transition and fate of the Levantine Intermediate Water (LIW. The results show that the adopted coupling techniques between the two models give a proficient downscaling of the large-scale OGCM flow field into the regional scale model. The numerical solution is also used to highlight the seasonal characteristics of important dynamical features in the area, as well as to shed light on the scarcely known circulation regimes along the north African shelf and slope.

    Key words. Oceanography: general (numerical modelling; Oceanography: physical (currents; general circulation

  2. Circulation in the South China Sea in summer of 1998

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on the CTD and meteorological data obtained by R/V Xiangyanghong No.14 in the South China Sea (SCS) in the summer of 1998, both current velocity and volume transport are calculated by using a modified inverse model. Circulation in the SCS is analyzed by combining the calculated results with ADCP data. The following results are obtained. (i) The most important feature of the circulation in the northeastern SCS is that a branch of the Kuroshio intrudes into the SCS with a small volume transport. It flows anticyclonically through the Bashi Strait and towards the southwest off the Taiwan Island, and it does not intrude into the inner SCS. (ii) The northern SCS is dominated mainly by a cyclonic circulation system with two cold eddies. (iii) The central and southwestern SCSs are mainly occupied by anticyclonic circulation systems, including three anticyclonic and one stronger cyclonic eddies. (iv) In the southeastern SCS, there is a large scope of cyclonic circulation extending in the SW-NE direction. (v) There is a "multi-eddy phenomenon" in the SCS, and a larger eddy contains several small eddies. (vi) There is western intensifying of the currents and eddies in the SCS.

  3. Experimental study of two-phase natural circulation circuit

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-07-01

    This paper reports an experimental study on the behavior of fluid flow in natural circulation under single-and two-phase flow conditions. The natural circulation circuit was designed based on concepts of similarity and scale in proportion to the actual operating conditions of a nuclear reactor. This test equipment has similar performance to the passive system for removal of residual heat presents in Advanced Pressurized Water Reactors (A PWR). The experiment was carried out by supplying water to primary and secondary circuits, as well as electrical power resistors installed inside the heater. Power controller has available to adjust the values for supply of electrical power resistors, in order to simulate conditions of decay of power from the nuclear reactor in steady state. Data acquisition system allows the measurement and control of the temperature at different points by means of thermocouples installed at several points along the circuit. The behavior of the phenomenon of natural circulation was monitored by a software with graphical interface, showing the evolution of temperature measurement points and the results stored in digital format spreadsheets. Besides, the natural circulation flow rate was measured by a flowmeter installed on the hot leg. A flow visualization technique was used the for identifying vertical flow regimes of two-phase natural circulation. Finally, the Reynolds Number was calculated for the establishment of a friction factor correlation dependent on the scale geometrical length, height and diameter of the pipe. (author)

  4. Multi-stage circulating fluidized bed syngas cooling

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guohai; Vimalchand, Pannalal; Guan, Xiaofeng; Peng, WanWang

    2016-10-11

    A method and apparatus for cooling hot gas streams in the temperature range 800.degree. C. to 1600.degree. C. using multi-stage circulating fluid bed (CFB) coolers is disclosed. The invention relates to cooling the hot syngas from coal gasifiers in which the hot syngas entrains substances that foul, erode and corrode heat transfer surfaces upon contact in conventional coolers. The hot syngas is cooled by extracting and indirectly transferring heat to heat transfer surfaces with circulating inert solid particles in CFB syngas coolers. The CFB syngas coolers are staged to facilitate generation of steam at multiple conditions and hot boiler feed water that are necessary for power generation in an IGCC process. The multi-stage syngas cooler can include internally circulating fluid bed coolers, externally circulating fluid bed coolers and hybrid coolers that incorporate features of both internally and externally circulating fluid bed coolers. Higher process efficiencies can be realized as the invention can handle hot syngas from various types of gasifiers without the need for a less efficient precooling step.

  5. Predisposing factors in posterior circulation infarcts: a vascular morphological assessment

    Energy Technology Data Exchange (ETDEWEB)

    Coban, Goekcen; Cifci, Egemen; Yildirim, Erkan; Agildere, Ahmet Muhtesem [Baskent University Faculty of Medicine, Department of Radiology, Konya (Turkey)

    2015-05-01

    The aim of the study is to assess the effect of shape, diameter, elongation and deviation criteria of basilar artery (BA), convergence angle and diameter variations of vertebral arteries, and concurrent chronic diseases on posterior circulation infarcts. Between January 2010 and May 2013, 186 patients who underwent brain and diffusion magnetic resonance imaging (MRI) with suspected cerebrovascular accident and were diagnosed with posterior circulation infarct and 120 infarct negative control subjects were included in this case-control retrospective study. Vertebral artery (VA) and BA diameter, right (R) and left (L) VA angles at the level of bifurcation, and BA elongation-deviation, and shape of BA were assessed in a total of 306 subjects. Ischemic lesions in the posterior circulation were classified according to their anatomical location and vascular perfusion areas. No significant difference was noted between the control and patient groups with respect to BA diameter (p = 0.676). The most effective risk factors for posterior circulation infarcts were as follows: BA elongation of 2 or 3, BA transverse location of 2 or 3, increase in left VA angle, and history of hypertension, hypercholesterolemia, and diabetes mellitus. Our results suggest that prominent elongation and deviation, C and J shape of BA, and increased L VA angle may be the predictors of at-risk patients in posterior circulation infarcts. Reporting marked morphological BA and VA variations detected at routine brain MRI will aid in selection of patients. Timely detection and treatment of at-risk patients may be life-saving. (orig.)

  6. Derivation of multipotent progenitors from human circulating CD14+ monocytes.

    Science.gov (United States)

    Seta, Noriyuki; Kuwana, Masataka

    2010-07-01

    Circulating CD14(+) monocytes are originated from hematopoietic stem cells in the bone marrow and believed to be committed precursors for phagocytes, such as macrophages. Recently, we have reported a primitive cell population termed monocyte-derived multipotential cells (MOMCs), which has a fibroblast-like morphology in culture and a unique phenotype positive for CD14, CD45, CD34, and type I collagen. MOMCs are derived from circulating CD14(+) monocytes, but circulating precursors for MOMCs still remain undetermined. Comparative analysis of gene expression profiles of MOMCs and other monocyte-derived cells has revealed that embryonic stem cell markers, Nanog and Oct-4, are specifically expressed by MOMCs. In vitro generation of MOMCs requires binding to fibronectin and exposure to soluble factors derived from activated platelets. MOMCs contain progenitors with capacity to differentiate into a variety of nonphagocytes, including bone, cartilage, fat, skeletal and cardiac muscle, neuron, and endothelium, indicating that circulating monocytes are more multipotent than previously thought. In addition, MOMCs are capable of promoting ex vivo expansion of human hematopoietic progenitor cells through direct cell-to-cell contact and secretion of a variety of hematopoietic growth factors. These findings obtained from the research on MOMCs indicate that CD14(+) monocytes in circulation are involved in a variety of physiologic functions other than innate and acquired immune responses, such as repair and regeneration of the damaged tissue.

  7. Stability of Thermohaline circulation with respect to fresh water release

    CERN Document Server

    Patwardhan, Ajay

    2008-01-01

    The relatively warm climate found in the North- Western Europe is due to the gulf stream that circulates warm saline water from southern latitudes to Europe. In North Atlantic ocean the stream gives out a large amount of heat, cools down and sinks to the bottom to complete the Thermohaline circulation. There is considerable debate on the stability of the stream to inputs of fresh water from the melting ice in Greenland and Arctic. The circulation, being switched off, will have massive impact on the climate of Europe. Intergovernmental panel on climate change (IPCC) has warned of this danger in its recent report. Our aim is to model the Thermohaline circulation at the point where it sinks in the North-Atlantic. We create a two dimensional discrete map modeling the salinity gradient and vertical velocity of the stream. We look for how a perturbation in the form of fresh water release can destabilise the circulation by pushing the velocity below a certain threshold.

  8. AIR RADIOACTIVITY MONITOR

    Science.gov (United States)

    Bradshaw, R.L.; Thomas, J.W.

    1961-04-11

    The monitor is designed to minimize undesirable background buildup. It consists of an elongated column containing peripheral electrodes in a central portion of the column, and conduits directing an axial flow of radioactively contaminated air through the center of the column and pure air through the annular portion of the column about the electrodes. (AEC)

  9. Air-Conditioning Mechanic.

    Science.gov (United States)

    Marine Corps Inst., Washington, DC.

    This student guide, one of a series of correspondence training courses designed to improve the job performance of members of the Marine Corps, deals with the skills needed by air conditioning mechanics. Addressed in the four chapters, or lessons, of the manual are the following topics: principles of air conditioning, refrigeration components as…

  10. The Air We Breathe

    Science.gov (United States)

    Davila, Dina

    2010-01-01

    Topics discussed include NASA mission to pioneer the future in space exploration, scientific discovery and aeronautics research; the role of Earth's atmosphere, atmospheric gases, layers of the Earth's atmosphere, ozone layer, air pollution, effects of air pollution on people, the Greenhouse Effect, and breathing on the International Space Station.

  11. Air/liquid collectors

    DEFF Research Database (Denmark)

    Jensen, Søren Østergaard; Olesen, Ole; Kristiansen, Finn Harken

    1997-01-01

    This report determine efficiency equations for combined air/liquid solar collectors by measurements on to different air/liquid collectors. Equations which contain all relevant informations on the solar collectors. A simulation program (Kviksol) has been modified in order to be able to handle...

  12. Bad Air For Children

    Science.gov (United States)

    Kane, Dorothy Noyes

    1976-01-01

    Children are especially sensitive to air pollution and consequences to them maybe of longer duration than to adults. The effects of low-level pollution on children are the concern of this article. The need for research on the threat of air pollution to childrens' health is emphasized. (BT)

  13. Air pollution and society

    OpenAIRE

    Brimblecombe P.

    2010-01-01

    Air pollution is as much a product of our society as it is one of chemistry and meteorology. Social variables such as gender, age, health status and poverty are often linked with our exposure to air pollutants. Pollution can also affect our behaviour, while regulations to improve the environment can often challenge of freedom.

  14. Over the air test

    DEFF Research Database (Denmark)

    2015-01-01

    [1] This invention relates to over-the-air testing of a device in an anechoic chamber. In particular, the invention is suitable for simulating both uplink and downlink over-the-air communication with a device under test even when the anechoic chamber has different numbers of uplink and downlink...

  15. Air Pollution, Teachers' Edition.

    Science.gov (United States)

    Lavaroni, Charles W.; O'Donnell, Patrick A.

    One of three in a series about pollution, this teacher's guide for a unit on air pollution is designed for use in junior high school grades. It offers suggestions for extending the information and activities contained in the textual material for students. Chapter 1 discusses the problem of air pollution and involves students in processes of…

  16. Air Pollution and Industry.

    Science.gov (United States)

    Ross, R. D., Ed.

    This book is an authoritative reference and practical guide designed to help the plant engineer identify and solve industrial air pollution problems in order to be able to meet current air pollution regulations. Prepared under the editorial supervision of an experienced chemical engineer, with each chapter contributed by an expert in his field,…

  17. Bearings Only Air-to-Air Ranging

    Science.gov (United States)

    1988-07-25

    sensor, observer and target parameters still remain. In order to reduce the number of cases to a manageable one, while preserving the geometric...perforance of variotu. ulro-air passive ranging tecnique has been examined as a fimn- tiam of uarget location andi motiom, observer motion. and length

  18. Restoran Buenos Aires = Restaurant Buenos Aires

    Index Scriptorium Estoniae

    2008-01-01

    Restorani Buenos Aires (Narva mnt. 5, Tallinn) sisekujundusest. Sisearhitektid: Janno Roos ja Andres Labi (Ruumilabor OÜ). Laudu eraldavad 400 vardasse aetud puukuuli. Sisearhitektidest, nende tähtsamad tööd. I-III korruse plaan, 12 värv. vaadet, fotod sisearhitektidest

  19. Numerical analysis of seawater circulation in carbonate platforms: II. The dynamic interaction between geothermal and brine reflux circulation

    Science.gov (United States)

    Jones, G.D.; Whitaker, F.F.; Smart, P.L.; Sanford, W.E.

    2004-01-01

    Density-driven seawater circulation may occur in carbonate platforms due to geothermal heating and / or reflux of water of elevated salinity. In geothermal circulation lateral contrasts in temperature between seawater and platform groundwaters warmed by the geothermal heat flux result in upward convective flow, with colder seawater drawn into the platform at depth. With reflux circulation, platform-top waters concentrated by evaporation flow downward, displacing less dense underlying groundwaters. We have used a variable density groundwater flow model to examine the pattern, magnitude and interaction of these two different circulation mechanisms, for mesosaline platform-top waters (50???) and brines concentrated up to saturation with respect to gypsum (150???) and halite (246???). Geothermal circulation, most active around the platform margin, becomes restricted and eventually shut-off by reflux of brines from the platform interior towards the margin. The persistence of geothermal circulation is dependent on the rate of brine reflux, which is proportional to the concentration of platform-top brines and also critically dependent on the magnitude and distribution of permeability. Low permeability evaporites can severely restrict reflux whereas high permeability units in hydraulic continuity enhance brine transport. Reduction in permeability with depth and anisotropy of permeability (kv < < kh) focuses flow laterally in the shallow subsurface (<1 km), resulting in a horizontally elongated brine plume. Aquifer porosity and dispersivity are relatively minor controls on reflux. Platform brines can entrain surficial seawater when brine generating conditions cease but the platform-top remains submerged, a variant of reflux we term "latent reflux". Brines concentrated up to gypsum saturation have relatively long residence times of at least 100 times the duration of the reflux event. They thus represent a long-term control on post-reflux groundwater circulation, and

  20. Norms and Spread of the Fibonacci and Lucas RSFMLR Circulant Matrices

    Directory of Open Access Journals (Sweden)

    Wenai Xu

    2015-01-01

    Full Text Available Circulant type matrices have played an important role in networks engineering. In this paper, firstly, some bounds for the norms and spread of Fibonacci row skew first-minus-last right (RSFMLR circulant matrices and Lucas row skew first-minus-last right (RSFMLR circulant matrices are given. Furthermore, the spectral norm of Hadamard product of a Fibonacci RSFMLR circulant matrix and a Lucas RSFMLR circulant matrix is obtained. Finally, the Frobenius norm of Kronecker product of a Fibonacci RSFMLR circulant matrix and a Lucas RSFMLR circulant matrix is presented.