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Sample records for bed estudio experimental

  1. Experimental study on fuel oil combustion in circulating fluidized bed; Estudio experimental sobre la combustion de combustoleo en lecho fluidizado circulante

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Rangel, Ricardo [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    The Instituto de Investigaciones Electricas (IIE) developed a circulating fluidized bed combustor of 0.5 thermal MW unique in its type in Latin America. The Bachelor`s thesis entitled ``Experimental Study on Fuel Oil Combustion in Circulating Fluidized Bed`` was performed operating this combustor with the purpose of determining the feasibility of burning heavy fuel oil in a stable and sustained form, as well as the effect of the addition of calcium carbonate to the combustor. The results of the experimental trials showed heavy fuel oil can be burned in a circulating fluidized bed, with low sulfur dioxide emissions. During the conduction of the experiments a sulfur retention of 43% was achieved with a Ca/S relationship of 4.5. [Espanol] El Instituto de Investigaciones Electricas (IIE) desarrollo un combustor de lecho fluidizado circulante de 0.5 MW termicos de potencia, unico en su tipo en Latinoamerica. La tesis de licenciatura titulada Estudio Experimental sobre la Combustion de Combustoleo en Lecho Fluidizado Circulante se realizo operando dicho combustor, con el proposito de determinar la factibilidad de quemar combustoleo pesado en forma estable y autosostenida, asi como la influencia que tiene la adicion de carbonato de calcio al lecho. Los resultados de los ensayos experimentales mostraron que se puede quemar combustoleo pesado en un lecho fluidizado circulante, con bajas emisiones de bioxido de azufre. Durante la experimentacion se logro una retencion de azufre del 43%, con una relacion Ca/S de 4.5.

  2. PARATIROIDECTOMIA ENDOSCOPICA. ESTUDIO EXPERIMENTAL EN EL PERRO

    Directory of Open Access Journals (Sweden)

    Jorge Ramón Lucena Olavarrieta

    2008-01-01

    Full Text Available La primera paratiroidectomía exitosa fue realizada en Viena, Austria, en 1925. Los procedimientos laparoscópicos estuvieron inicialmente limitadas a las zonas corporales con cavidades preexistentes, recientemente, el acceso a espacios anatómicos potenciales ha extendido las indicaciones de la cirugía endoscópica minimamnete invasiva.Desde el primer reporte sobre la paratiroidectomía endoscópica en 1996, las técnicas video-asistidas han comenzado a utilizarse en la cirugía del cuello, y en varias series se han documentado la factibilidad y seguridad de este tipo de abordaje. La finalidad de esta investigación fue el determinar la factibilidad, seguridad y eficacia de la paratiroidectomía endoscopia en el modelo canino.Entre el 25 de noviembre del 2005 y 15 de octubre del 2007, se intervinieron en el Instituto de Cirugía Experimental de la Universidad Central de Venezuela 31 perros, mestizos sanos desparasitados,asignándose a dos grupos: homogéneos "A" 16, a cirugía convencional, "B" 15 a cirugía video-asistida. Se midieron las siguientes variables; sexo, peso, exámenes de laboratorio, laringoscopia pre y postoperatoria, posición, dirección de la incisión, longitud, localización, valores pre y postoperatorios de calcio, fósforo, proteína C reactiva, hemoglobina, hematocrito, tipo de disección, número y posición de las paratiroides, identificación de los nervios recurrentes y rama externa del nervio laríngeo superior, sangramiento, dificultades intraoperatorias, tiempo, resultado del estudio histopatológico.Las deducciones de este estudio experimental proporcionan evidencias de que la paratiroidectomía endoscópica es factible y segura. El abordaje mínimo tiene mejores resultados cosméticos y el potencial de disminuir la morbi-mortalidad.

  3. EXPERIMENTAL RESEARCH OF CYLINDER-TO-BED HEAT TRANSFER IN AGITATED FLUIDIZED BEDS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Cylinder-to-bed heat transfer in agitated fluidized beds was studied experimentally.In the experiments, the aluminum particles were used as bed material, the diameter of which ranges from 0.5mm to 2mm.The effects of gas velocity, particles size, and agitator rotary speed on heat transfer were studied.From the experimental results, we have come to the following conclusions: (1) There are optimal ranges for airflow velocity and rotary speed to get optimal heat transfer coefficient; (2) The cylinder-to-bed heat transfer is greatly affected by gas velocity, rotary speed and particles sizes and the effect of rotary speed on heat transfer is similar to that of gas velocity; (3) Higher heat transfer coefficient is obtained with smaller particles.

  4. Experimental Simulation for Fracture of Gun Propellant Charge Bed

    Institute of Scientific and Technical Information of China (English)

    RUI Xiao-ting; YUN Lai-feng; WANG Hao; HUANG Ming; CHEN Jian-zhong; CHEN Tao; LIU Jun

    2005-01-01

    The simulation of compression and fracture of charge bed in chamber is one of the key problems in the study of launch safety of gun propellant charge. A new kind of experimental device that can be used for simulation is given. Its structure and operational principle are introduced. Using a semi-closed vessel as a source of compression force, the device can simulate any kind of dynamic environment in a gun propellant charge. Using the low temperature inert gas (N2) as the compression medium, the device can not only ensure that the simulation is real, but also protect the fragmentized propellant from combustion after experiment. Using the device, many simulation experiments have been accomplished, and dynamic environment of propellant fracture is acquired. With the experiments, fragmentized propellant for the compression and fracture of charge bed is obtained. Results of experiments show that the new device can be used to study the principle of the compression and fracture of charge bed.

  5. INITIATION OF SHELL MOTION ON SAND BEDS: AN EXPERIMENTAL STUDY

    Institute of Scientific and Technical Information of China (English)

    Subhasish DEY; Alok KUMAR

    2002-01-01

    Experimental study on initiation of bivalve shell motion on a horizontal sand bed, under a unidirectional flow of water, is presented. Experiments were carried out in a flume with three types of bivalve shells,namely Coquina Clam, Cross-barred Chione and Ponderous Ark, to test the condition for initiation of motion. The shape parameters of bivalve shells are defined appropriately. Experiments were conducted in a flume with a horizontal bed, and the critical shear stresses were estimated using Vanoni's side-wall correction. The characteristic parameters affecting the initiation of shell motion on a horizontal bed in rough-turbulent regime identified based on the physical reasoning and dimensional analysis are the Shields parameter (nondimensional critical shear stress), nondimensional competent mean velocity,nondimensional sand roughness, nondimensional flow depth and shape parameter. Equations of Shields parameter and nondimensional competent mean velocity for the initial movement of shells on a horizontal sand bed with convex upward and downward conditions are obtained using experimental data.

  6. Estudio experimental de rejillas en bocatoma de fondo.

    OpenAIRE

    Pérez Parra, Jorge Arturo; Quiceno Restrepo, Carlos; Botero Mesa , Mauricio; Cano Giraldo, Andrés Felipe

    1998-01-01

    Las rejillas que hacen parte de una estructura de captación se diseñan, normalmente, utilizando un procedimiento matemático que luego es afectado por un amplio factor de seguridad. Con dicho procedimiento se encuentra que cualquier tipo de rejilla con espesor y separación de barras aceptados por las normas del país, cumple con la captación del caudal requerido. Tratando de racionalizar el diseño se realiza este estudio experimental en una bocatoma de fondo cuya rejilla está ubicada por debaj...

  7. Experimental simulation of gravity currents in erodible bed

    Science.gov (United States)

    Bateman, A.; La Roca, M.; Medina, V.

    2009-04-01

    Gravity currents are commonly met in nature, when a flow of denser fluid moves into a less dense one. A typical example of a gravity current is given by the sea water which flows into the bottom of a river during the summer, in correspondence of the estuary, when the river's discharge attains low values. In this case, dangerous consequences can occur, because of the polluting of the aquifer caused by the salty water. Density currents also occurs in lakes and reservoirs, because of a change in temperature or because a flood, both can produce some environmental impacts that are of interest to the local water Agency of the different countries. Of particular relevance is also the interaction of the gravity current with the movement of the sediments from the bottom of the bed. The international state of the art is particularly concerned with experimental and numerical investigation on gravity currents on fixed and porous bed [1-2-3], while, to the authors' knowledge, the interaction of a gravity current with an erodible bed is still an open field of investigation. In this paper experiments concerning with the propagation of a gravity current over fixed and erodible bed are presented. The experiments, conducted at the laboratory of Hydraulics of the Universitat Politecnica de Catalunya (actually in the Prof. Bateman's blue room), were concerned with a transparent tank 2 m long, 0.2 m wide and 0.3 m deep, partly filled with salty water and partly with fresh water, up to a depth of 0.28 m. The salty water, whose density was in the range 1050John E. Simpson. Gravity Currents [3] J.J. Monaghan, R.A.F. Cas, A.M. Kos, M. Hallworth, Gravity currents descending a ramp in a stratified tank, The Journal of Fluid Mechanics, Vol. 379, 1999

  8. Tiempo de Respuestas y Experiencia de Usuario Estudio Experimental

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    Delvis Echeverria

    2016-12-01

    Full Text Available La investigación está fundamentada por un estudio experimental, enfocado en la evaluación del comportamiento de los usuarios finales interactuando con tiempos de respuestas en aplicaciones reales. Se tomará como base el aporte de los autores Doherty y Thadani, investigadores de IBM relacionado con los tiempos de respuestas, y las investigaciones de Jacob Nielsen. Se llevarán a cabo un test con usuarios finales, y se expondrán optimizaciones a través de del uso de herramientas que contribuirán a mejorar los tiempos de respuestas de las aplicaciones web. Todo esto engloba una primera instancia de un proyecto que se está llevando a cabo en la empresa GeneXus Consulting, pretendiéndose lograr un punto de encuentro entre el rendimiento de las aplicaciones y la experiencia de usuario.

  9. Optimisation of Experimental Conditions for Ex-Bed Desulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, J. M.; Ruiz, E.; Otero, J.

    2010-12-22

    This report compiles the results of the work conducted by CIEMAT for Task 6.3 Sulfur and Nitrogen Compounds Abatement of the FLEXGAS project Near Zero Emission Advanced Fluidized Bed Gasification, which has been carried out with financial support from the Research Fund for Coal and Steel, RFCR-CT-2007-00005. The assignment of CIEMAT in Task 6.3 has dealt with the experimental study of ex-bed desulfurization at high temperature and high pressure. Based on a review of the state of the art, a zinc oxide sorbent was chosen as a promising candidate for bulk sulfur removal in highly reducing gases such as those from coal and waste oxygen gasification or for a polishing stage in low sulfur content gases, which is typically the case in biomass gasification gases. The work accomplished has included the study of the sulfidation and regeneration stages in order to determine successful operating conditions and the assessment of the long term performance of the sorbent over subsequent sulfidation and regeneration cycles. (Author) 36 refs.

  10. Experimental investigation of nanoparticles precipitation in a rotating packed bed

    Institute of Scientific and Technical Information of China (English)

    Yang Xiang; Guangwen Chu; Lixiong Wen; Kuang Yang; Guangting Xiao; Jianfeng Chen

    2010-01-01

    Precipitation of BaSO4 nanoparticles was studied for the first time in a specially designed rotating packed bed(RPB),which allowed sampling at different radial positions to provide better insight of the mechanism of precipitation in RPB.Particle size and morphology were characterized by TEM,while the quality of synthesized BaSO4 powders was analyzed by XRD and BET,and compared with those prepared in a stirred-tank reactor.The important role of the inlet region of the RPB in the whole precipitation process was experimentally confirmed,as a significant essence for the design of industrial RPB for the precipitation of sparingly soluble materials.The effects of different operating conditions on particle size were also investigated,showing that particle size decreases with increasing rotational speed and liquid flow rate,due to the enhancement of micromixing in the RPB.

  11. Computational and Experimental Study of Spherocylinder Particles in Fluidized Beds

    Science.gov (United States)

    Mahajan, Vinay; Kuipers, Hans; Padding, Johan; Multiphase Reactors Group, TU Eindhoven Team

    2016-11-01

    Non-spherical particle flows are often encountered in fluidized process equipment. A coupled computational fluid dynamics (CFD) and discrete element method(DEM) approach has been extensively applied in recent years to study these flows at the particle scale. However, most of these studies focus on spherical particles while in reality, the constituent particles are seldom spherical. Particle shape can significantly affect the hydrodynamical response in fluidized beds. The drag force acting on a non-spherical particle can vary considerably with particle shape, orientation of the particle, Reynolds number and packing fraction. In this work, a CFD-DEM approach has been extended to model a lab scale quasi-2D fluidized bed of spherocylinder (rod-like) particles. These particles can be classified as Geldart D particles and have an aspect ratio of 4. Numerical results for the pressure drop, bed height and solid circulation patterns are compared with results from a complementary laboratory experiment. We also present results on particle orientations close to the confining walls, which provides interesting insight regarding the particle alignment. Thus the capability of the CFD-DEM approach to efficiently account for global bed dynamics in fluidized bed of rod-like particle is demonstrated. This research work is funded by ERC Grant.

  12. Grimethorpe experimental pressurized fluidized-bed combustor: in future energy concepts

    Energy Technology Data Exchange (ETDEWEB)

    Broadbent, D.B.

    1979-01-01

    The experimental pressurized fluidized bed combustor project at Grimethorpe, UK, is described. The design of the combustor, which is a pressure vessel containing a furnace, which contains the fluidized bed is discussed. Details of the process, the steam water circuit, the fuel system and method of feeding coal, ash removal during the process, the water treatment plant and plant control are given.

  13. Moisture Transport in Silica Gel Packed Beds: II. Experimental Study

    Energy Technology Data Exchange (ETDEWEB)

    Pesaran, A. A.; Mills, A. F.

    1986-08-01

    Experiments have been performed to obtain the transient response of a thin adiabatic packed bed of silica gel after a step change in inlet air conditions, comparisons are made with predictions using a solid-side resistance model and a pseudo-gas-side controlled model and better agreement obtained with the former model.

  14. An experimental analysis of bed load transport in gravel-bed braided rivers with high grain Reynolds numbers

    Science.gov (United States)

    De Vincenzo, Annamaria; Brancati, Francesco; Pannone, Marilena

    2016-08-01

    Laboratory experiments were performed with nearly uniform fluvial gravel (D50=9 mm, D10=5 mm and D90=13 mm) to analyse the relationship between stream power and bed load transport rate in gravel-bed braided rivers at high grain Reynolds numbers. The values of the unit-width dimensionless bed-load rate qb* and unit-width dimensionless stream power ω* were evaluated in equilibrium conditions based on ten different experimental runs. Then, they were plotted along with values obtained during particularly representative field studies documented in the literature, and a regression law was derived. For comparison, a regression analysis was performed using the data obtained from laboratory experiments characterized by smaller grain sizes and, therefore, referring to relatively low grain Reynolds numbers. A numerical integration of Exner's equation was performed to reconstruct the local and time-dependent functional dependence of qb* and ω*. The results led to the following conclusions: 1) At equilibrium, the reach-averaged bed load transport rate is related to the reach-averaged stream power by different regression laws at high and low grain Reynolds numbers. Additionally, the transition from bed to suspended load transport is accelerated by low Re*, with the corresponding bed load discharge increasing with stream power at a lower, linear rate. 2) When tested against the gravel laboratory measurements, the high Re* power law derived in the present study performs considerably better than do previous formulas. 3) The longitudinal variability of the section-averaged equilibrium stream power is much more pronounced than that characterizing the bed load rate, at least for high Re*. Thus, the stream power and its local-scale heterogeneity seem to be directly responsible for transverse sediment re-distribution and, ultimately, for the determination of the spatial and temporal scales that characterize the gravel bedforms. 4) Finally, the stochastic interpretation of the wetted

  15. Estudio experimental de la Osteonecrosis producida por Bisfosfonatos Nitrogenados

    OpenAIRE

    2010-01-01

    Se realizó un análisis del efecto profiláctico del tratamiento antibiótico en ratas Sprague-Dawley tratadas con dexametasona más pamidronato y sometidas a cirugía oral. Se incluyeron un total de 120 animales en un estudio prospectivo randomizado integrado por dos grupos con 60 animales cada uno, en tratamiento diario con dexametasona y pamidronato durante 7, 14 y 21 días. Todas fueron sometidas a extracción del molar derecho mandibular o maxilar. Además a un grupo se le añadió penicilina … [+...

  16. An Experimental and Numerical Investigation of Fluidized Bed Gasification of Solid Waste

    OpenAIRE

    Sharmina Begum; Mohammad G. Rasul; Delwar Akbar; David Cork

    2013-01-01

    Gasification is a thermo-chemical process to convert carbon-based products such as biomass and coal into a gas mixture known as synthetic gas or syngas. Various types of gasification methods exist, and fluidized bed gasification is one of them which is considered more efficient than others as fuel is fluidized in oxygen, steam or air. This paper presents an experimental and numerical investigation of fluidized bed gasification of solid waste (SW) (wood). The experimental measurement of syngas...

  17. Experimental Investigation of Pressure Drop Hysteresis in a Cocurrent Gas-Liquid Upflow Packed Bed

    Institute of Scientific and Technical Information of China (English)

    徐红彬; 毛在砂

    2001-01-01

    Extensive experimental work on hysteresis in a cocurrent gas-liquid upflow packed bed was carried out with three kinds of packings and the air-water system. However, only when packed with small glass beads (φ1.4 mm) was the bed pressure drop hysteresis observed. Two more liquids with different liquid properties were employed to further examine the influence of parameters on pressure drop hysteresis. The similarity of pressure drop hysteresis in packed beds was concluded in combination of experimental evidence reported in literature.

  18. Experimental study on temperature characteristics and energy conversion in packed bed reactor with dielectric barrier discharge

    Science.gov (United States)

    Li, Sen; Tang, Zuchen; Gu, Fan

    2010-10-01

    The temperature characteristics and energy conversion in packed bed reactor combined with a dielectric barrier discharge (DBD) plasma was investigated experimentally. The pellet temperatures of two types packed bed reactor, cylindrical reactor and parallel-plate reactor, was measured in conditions of various inlet voltage of DBD plasma. The relationship between pellet temperature of the packed bed and applied voltage of DBD plasma was discovered. The experimental result indicates a tendency that the pellet temperature of packed bed increases as the applied voltage of inlet plasma increases. When the voltage of inlet plasma is high enough, the pellet temperature increment decreases. Simultaneously,the packed bed temperature is sensitive to the inlet plasma energy and there is a potential application to heat exchanger. Moreover the proportion of energy consumption of plasma inputting into packed bed reactor was analyzed and calculated. The mechanisms that electrical energy of inlet plasma is transformed into heat energy in the two phases, gaseous and pellets of the packed bed reactor are different. The energy consumption in pellet phase is dielectric polarization loss and depends on packed bed geometry and DBD plasma etc. The energy consumption in gaseous phase is plasma sheath procedure. The important factors effecting on gas discharge are gaseous component and voltage, frequency of power.

  19. Experimental study of sediment particle diffusion on a granular bed.

    Science.gov (United States)

    Antico, Federica; Sanches, Pedro; Fent, Ilaria; Ferreira, Rui M. L.

    2016-04-01

    Particle diffusion in a cohesionless granular bed, hydraulically fully rough, subjected to a steady-uniform turbulent open-channel flow is investigated. Experiments were carried out under conditions of weak bedload transport in a 12.5 m long and 40.5 cm wide glass-sided flume recirculating water and sediment through independent circuits at the Laboratory of Hydraulics and Environment of Instituto Superior Técnico, Lisbon. The flume bed was divided in two reaches: a fixed reach comprising 1.5 m of large boulders, followed by 3.0 m of smooth bottom (PVC) and 2.5 m of one layer glued 5.0 mm diameter spherical glass beads; a mobile reach 4.0 m long and 2.5 cm deep filled with 5.0 mm diameter glass packed beads. Particle velocities were obtained introducing 5.0 mm diameter white-coated beads in the flow. Particle motion was registered from above using a high-speed camera AVT Bonito CL-400 with resolution set to 2320 x 1000 px2and frame rate of 170 fps. The field of view recorded was 77.0 cm long and 38.0 cm wide, covering almost all the width of the flume. Image processing allowed detecting and locating the centre of mass of the particles with sub-pixel accuracy. Particle trajectories were reconstructed by tracking the beads in the images; particle velocities were obtained as bead displacement over time interval between two consecutive frames (1/170 s). The computation of lagrangian statistics of particle velocities for a Shields parameter θ=0.014, Froude number Fr=0.756, boundary Reynolds number Re*=182.9 and run duration of 20 min (during which 1218 particle trajectories were collected) provided information about particle diffusion within the local and intermediate range of temporal and space scales. Mean particle velocities, second, third and fourth order moments were obtained for both longitudinal and transverse velocity components. A relatively large ballistic range, approximately two particle diameters, was observed, mainly due to the simple bed topography of

  20. Thermo-mechanical test rig for experimental evaluation of thermal conductivity of ceramic pebble beds

    Energy Technology Data Exchange (ETDEWEB)

    Lo Frano, Rosa, E-mail: rosa.lofrano@ing.unipi.it; Aquaro, Donato; Pupeschi, Simone; Moscardini, Marigrazia

    2014-10-15

    Highlights: • Thermal conductivity values of bed as function of a material of known conductivity. • Minimizing the error caused by radial heat transfer. • Experimental evaluation of thermal conductivity of alumina pebble at different temperatures. • Experimental test with/without compression load. - Abstract: The experimental determination of mechanical and thermal properties of ceramic pebble beds, such as the lithium orthosilicate or lithium metatitanate, is a key issue in the framework of fusion power technology, for the reason that they are possible candidates in the design of breeder blankets. The paper deals with an experimental method for the evaluation of the thermal conductivity of ceramic pebble beds versus the temperature and compressive strain, based on a steady state heat flux through a material (alumina) of known conductivity. The alumina thermal conductivity is determined by means of the hot wire method. To assess the experimental method, a thermo-mechanical characterization of alumina pebble beds (a material largely available), having different diameters, considering a wide range of temperatures and compression forces has been carried out. Moreover preliminary tests have been performed on lithium orthosilicate and lithium metatitanate pebble beds.

  1. Estudio experimental del llenado de moldes pulvimetalúrgicos

    Directory of Open Access Journals (Sweden)

    Istúriz, A.

    2005-12-01

    Full Text Available Die filling is the first step in the process of powder compaction. The density distribution depends of the powder characteristics and method of filling. In this work we present the first results obtained with different experimental methods of the filling. Results have been analyzed using a video system which permits the observation of the powder flow. The aim of the work is to determinate the effects of size, morphology and nature of the powder, as well as shoe speed, and die geometry on the apparent density distribution in industrial dies of complex geometry.

    En el proceso de conformado pulvimetalúrgico, la consolidación del polvo se inicia con el llenado del molde en el que se fabricará la preforma porosa, el cual está caracterizado por la distribución de densidades del polvo dentro del molde y depende tanto de las propiedades del mismo como del método de llenado utilizado. A continuación, presentamos los primeros resultados obtenidos mediante un montaje experimental que reproduce el llenado de moldes y que, empleando un sistema de video, permite analizar el flujo de las partículas durante el llenado. El objetivo es determinar el efecto del tamaño, naturaleza y morfología del polvo, así como el de la velocidad del cargador y la geometría del molde en la distribución de la densidad aparente en moldes industriales de geometría compleja.

  2. Experimental Study on a New Dual-Layer Granular Bed Filter for Removing Particulates

    Institute of Scientific and Technical Information of China (English)

    YANG Guo-hua; ZHOU Jiang-hua

    2007-01-01

    A new dual-layer granular bed filter for hot gas cleanup was invented and studied experimentally. Fine sand, 0.5-1 mm grain size and about 1350 kg/m3 bulk density, was used as the lower layer of the filter. Expanded perlite particles, 2-5 mm grain size and about 70 kg/m3 bulk density, was used for the upper layer of the filter in this study. It was confirmed that the sizes and densities of these two media matched well; the binary media remained in complete segregation during regeneration by fluidization. Test results show that the filtration of the expanded perlite particle layer was characterized as "deep bed filtration." Filtration of the fine sand layer was "surface cake filtration." The expanded perlite particle layer contributed about 90% to the bed dust capacity, but only about 20% to the total bed pressure drop, which increased the bed dust capacity ten fold compared to a single-layer bed of the same sand and the same total bed pressure drop. The dust cake on the surface of the fine sand layer raised the collection efficiencies to over 99.99%.

  3. Heat transfer in packed beds: experimental evaluation of one-phase water flow

    Directory of Open Access Journals (Sweden)

    J. C. Thoméo

    2004-01-01

    Full Text Available Experimental heat transfer studies were carried out in 50.8 mm diameter packed beds of glass beads percolated by water and heated from the wall. The tube-to-particle diameter ratio (D/d p ranged from 1.72 to 13.7 and the water flow rate from 1.1 to 9.9 l/min. Bed heights ranged from 100 mm to 700 mm. The radial temperature was measured above the bed surface by five aligned sheathed thermocouples. Variations in angular temperature were observed, independent of both radial position and particle diameter. Results of repeated tests with the same packing and with repacking did not differ statistically. The radial temperature profile at the bed entrance, measured by a ring-shaped sensor, was uniform except very close to the tube wall.

  4. EXPERIMENTAL STUDY OF LANDSLIDE DAM-BREAK FLOOD OVER ERODIBLE BED IN OPEN CHANNELS

    Institute of Scientific and Technical Information of China (English)

    YAN Jun; CAO Zhi-xian; LIU Huai-han; CHEN Li

    2009-01-01

    Large-scale landslide dams may block the river flow and cause inundation upstream,and subsequently fail and result in severe flooding and damage in the downstream.The need for enhanced understanding of the inundation and flooding is evident.This article presents an experimental study of the inundation and landslide dam-break flooding over erodible bed in open channels.A set of automatic water-level probes is deployed to record the highly transient stage,and the post-flooding channel bed elevation is measured.New experimental data resources are provided for understanding the processes of landslide-induced flooding and for testing mathematical rivers models.

  5. Membrane assisted fluidized bed reactor: experimental demonstration for partial oxidation of methanol

    NARCIS (Netherlands)

    Deshmukh, Salim Abdul Rashid Khan

    2004-01-01

    In this thesis the reactor concept has been developed on the basis of an experimental study on the effect of fluidization conditions on the membrane permeation rate in a MAFBR, the extent of gas back mixing and the tube-to-bed heat transfer rates in the presence of membrane bundles with and without

  6. EXPERIMENTAL STUDY ON DAM-BREAK FLOOD WAVES OVER MOVABLE BED CHANNEL

    Institute of Scientific and Technical Information of China (English)

    J.B.LEAL; R.L.FERREIRA; A.B.FRANCO; A.H.CARDOSO

    2002-01-01

    This paper presents the results of an experimental study focused on the propagation of dam-break flow waves over movable beds.Tests consisted in the sudden opening of a vertical lift-gate which separated initial water and sediment levels upstream and downstream of the gate.They allowed the simulation of the following initial conditions: with or without initial bed-step at the gate cross-section; with or without water downstream of the gate; with or without sediments downstream of the gate.Test results were used to discuss the influence of the movable bed on the celerity of the wave-fronts,as well as on the downstream wave-front height.The total volume of dislodged sediments was also assessed.Some important conclusions were achieved: i) the movable bed does not affect the upstream wave-front celerity but it affects the celerity of the downstream wave-front; ii) the experimental celerities show some disagreement with the analytical solutions; iii) the existence of an initial bed-step at the lift-gate cross-section influences the downstream wave-front propagation,including the water depth.

  7. EXPERIMENTAL STUDY ON INCIPIENT MOTION OF SEDIMENT PARTICLES ON GENERALIZED SLOPING FLUVIAL BEDS

    Institute of Scientific and Technical Information of China (English)

    Subhasish DEY

    2001-01-01

    This paper presents an experimental investigation on incipient motion of non-cohesive uniform sediment under a steady-uniform stream flow on generalized sloping fluvial beds (combined lateral and stream-wise slope). The characteristic parameters affecting the incipient motion of sediment particles, identified based on the physical reasoning and dimensional analysis, are the threshold shear stress ratio (ratio of threshold shear stress for sloping bed to that for horizontal bed), lateral slope,stream-wise slope and angle of repose of sediment particles. Experiments were carried out in two ducts (closed-conduit flow) having section of semicircular invert with three types of sediments. In an open channel flow (laboratory flume study), the uniform flow is a difficult, if not impossible,proposition for a steeply sloping channel and is impossible to obtain in an adversely sloping channel.To avoid this problem, the tests were conducted with a closed-conduit flow. Equation of critical bed shear stress for the initial movement of sediment particles on generalized sloping beds was obtained using the experimental data.

  8. Experimental investigation of thermal conductivity coefficient and heat exchange between fluidized bed and inclined exchange surface

    Directory of Open Access Journals (Sweden)

    B. Stojanovic

    2009-06-01

    Full Text Available The paper presents experimental research of thermal conductivity coefficients of the siliceous sand bed fluidized by air and an experimental investigation of the particle size influence on the heat transfer coefficient between fluidized bed and inclined exchange surfaces. The measurements were performed for the specific fluidization velocity and sand particle diameters d p=0.3, 0.5, 0.9 mm. The industrial use of fluidized beds has been increasing rapidly in the past 20 years owing to their useful characteristics. One of the outstanding characteristics of a fluidized bed is that it tends to maintain a uniform temperature even with nonuniform heat release. On the basis of experimental research, the influence of the process's operational parameters on the obtained values of the bed's thermal conductivity has been analyzed. The results show direct dependence of thermal conductivity on the intensity of mixing, the degree of fluidization, and the size of particles. In the axial direction, the coefficients that have been treated have values a whole order higher than in the radial direction. Comparison of experimental research results with experimental results of other authors shows good agreement and the same tendency of thermal conductivity change. It is well known in the literature that the value of the heat transfer coefficient is the highest in the horizontal and the smallest in the vertical position of the heat exchange surface. Variation of heat transfer, depending on inclination angle is not examined in detail. The difference between the values of the relative heat transfer coefficient between vertical and horizontal heater position for all particle sizes reduces by approximately 15% with the increase of fluidization rate.

  9. Numerical Simulation and Experimental Study of Deep Bed Corn Drying Based on Water Potential

    Directory of Open Access Journals (Sweden)

    Zhe Liu

    2015-01-01

    Full Text Available The concept and the model of water potential, which were widely used in agricultural field, have been proved to be beneficial in the application of vacuum drying model and have provided a new way to explore the grain drying model since being introduced to grain drying and storage fields. Aiming to overcome the shortcomings of traditional deep bed drying model, for instance, the application range of this method is narrow and such method does not apply to systems of which pressure would be an influential factor such as vacuum drying system in a way combining with water potential drying model. This study established a numerical simulation system of deep bed corn drying process which has been proved to be effective according to the results of numerical simulation and corresponding experimental investigation and has revealed that desorption and adsorption coexist in deep bed drying.

  10. EXPERIMENTAL STUDY ON THE RELATION OF BED MORPHOLOGY WITH SURFACE FLOW IN MEANDER CHANNELS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Alternate bars have the property that they migrate downstream whenever floods occur. However,in meander channels whose bend angles are larger than a critical value, the migration of bars can be suppressed, and the positions of bank erosion and flood attack also will be steady. In this study, the bed morphology in flume channels with bends of various lengths and angles is investigated at various flow discharges, and the relation of bed morphology to surface flow is investigated in detail using fluid measuring software. An effort is made to obtain guidelines for the plane shape design of meander channels. Based on the experimental results of bed topography and measurement of surface flow direction and velocity distribution, from the viewpoint of bank erosion and the concentration and dispersion of flood flow the most suitable plane shape for meandering channels is suggested through which the migration of alternate bars is suppressed.

  11. An Experimental Investigation on the Drying of Sliced Food Products in Centrifugal Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    M.H.Shi; Y.L.Hao; 等

    1998-01-01

    An experimental investigation on the fluidization and drying characteristics of sliced food products in a centrifugal fluidized bed dryer was carried out,The rotaing speed ranges from 300 rpm to 500 rpm.Sliced potato and radish were used as the testing materials.The results show that the sliced materials can be fluidized well in the centrifugal fluidized bed.The fluidized curve has a maximum value and the critical fluidized velocities vary with the type of the test material,its shape and dimension as well as operating parameters.The sliced food materials can be dried very well and fast in the centrifugal fluidized bed with a large productivity.The factors that influence the drying process were examined and discussed.The final shape and inner structure of the dried products were observed.The water recovery characteristics of the drried products were also investigated.

  12. Two-dimensional mathematical model of a packed bed dryer and experimentation

    Energy Technology Data Exchange (ETDEWEB)

    Basirat-Tabrizi, H.; Saffar-Avval, M.; Assarie, M.R. [Amirkabir University of Technology, Tehran (Iran). Dept. of Mechanical Engineering

    2002-04-01

    A comprehensive heat and mass transfer model, based on the Eulerian two fluid model (TFM), developed for a packed-bed-drying process. The temperature and moisture content in a particle was considered with the conjugate effects between the gas and particles in a packed bed. Numerical study of the model was carried out on two-dimensional, axi-symmetrical cylindrical coordinates in order to investigate the effects of the different parameters such as particle size, variation of inlet gas temperature on the moisture content, and temperature of solid and gas outlet. For experimental observations, an experimental apparatus was designed and utilized. The theoretical results were then compared to the experimental data, which indicated good agreement. (author)

  13. Experimental analysis and evaluation of the mass transfer process in a trickle-bed reactor

    Directory of Open Access Journals (Sweden)

    Silva J.D.

    2003-01-01

    Full Text Available A transient experimental analysis of a three-phase descendent-cocurrent trickle-bed H2O/CH4-Ar/g -Al2O3 system was made using the stimulus-response technique, with the gas phase as a reference. Methane was used as a tracer and injected into the argon feed and the concentration vs time profiles were obtained at the entrance and exit of the bed, which were maintained at 298K and 1.013 10(5 Pa. A mathematical model for the tracer was developed to estimate the axial dispersion overall gas-liquid mass transfer and liquid-solid mass transfer coefficients. Experimental and theoretical results were compared and shown to be in good agreement. The model was validated by two additional experiments, and the values of the coefficients obtained above were confirmed.

  14. A Cold Model Experimental Study on the Flow Characterisitcs of Bed Baterial in A Fluidized ed Bottom Ash Cooler in a CFB Boiler

    Institute of Scientific and Technical Information of China (English)

    LuXiaofeng; LiYourong

    2000-01-01

    A cold model experimental study on the flowing characteristics of bed meterial between a fluidized bed ash cooler and a furnace of CFB boiler were discussed in this paper.The research results showed that flowing status of the bed material in a bubbling bed,which was run with a circulating fluidized bed together in parallel operation,was influenced by the pressure difference between the CFB and the bubbling bed,the switch status of unlocking air ,and the structure of the exit of the bubbling bed.There was a circulating flow of bed material between CFB and bubbling bed.

  15. Experimental Study and Modelling of Char Combustion under Fluidized Bed Conditions

    Institute of Scientific and Technical Information of China (English)

    ZhangYongzhe; ManfredC.Wirsum; 等

    1998-01-01

    The combustion behavior of chars from two Chinese coals has been investigated in a laboratory scale bubbling fludized bed system in Siegen University,Germany,Experimental equipment and method are introduced.The shrinking-core model and the “shrinking-particl” model were employed to evaluate the kinetic parameters.The results indicated that the char conversion process of these two coals can be well described by the two models.

  16. Nonlinear analysis of experimental noisy time series in fluidized bed systems

    CERN Document Server

    Caputo, E; Marcolongo, V

    1994-01-01

    Abstract: The paper describes the application of some numerical techniques to analyze and to characterize the observed dynamical behaviour of fluidized bed systems. The preliminary results showed clearly that the dynamics of the considered process can be nonrecurrent and governed by chaotic deterministic rules rather than by stochastic ones. This significant conclusion was allowed by the application of a proper filtering procedure which was able to reduce the unwanted influence of significant broadband noise detected in the sampled experimental data.

  17. Estudio experimental y teórico de mezclas binarias de aminas y cetonas

    OpenAIRE

    Alonso Miguel, Iván

    2014-01-01

    Contribución Experimental: Calibrado y puesta a punto del densímetro Anton Paar DSA 5000 y del microcalorímetro Tian-Calvet. Determinación de los volúmenes, las compresibilidades isoentrópicas y las entalpías de exceso de mezclas amina + cetona o + n-alcano. El estudio se ha completado con el análisis espectroscópico de mezclas 2-butanona + amina. Contribución Teórica: Formulación de las ecuaciones de la Termodinámica de mezclas. Estudio mecánico-estadístico de líquido...

  18. Theoretical and experimental studies of fixed-bed coal gasification reactors. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, B.; Bhattacharya, A.; Salam, L.; Dudukovic, M.P.

    1983-09-01

    A laboratory fixed-bed gasification reactor was designed and built with the objective of collecting operational data for model validation and parameter estimation. The reactor consists of a 4 inch stainless steel tube filled with coal or char. Air and steam is fed at one end of the reactor and the dynamic progress of gasification in the coal or char bed is observed through thermocouples mounted at various radial and axial locations. Product gas compositions are also monitored as a function of time. Results of gasification runs using Wyoming coal are included in this report. In parallel with the experimental study, a two-dimensional model of moving bed gasifiers was developed, coded into a computer program and tested. This model was used to study the laboratory gasifier by setting the coal feed rate equal to zero. The model is based on prior work on steady state and dynamic modeling done at Washington University and published elsewhere in the literature. Comparisons are made between model predictions and experimental results. These are also included in this report. 23 references, 18 figures, 6 tables.

  19. Estudio experimental de la cavitación en tubos de Venturi

    OpenAIRE

    Zabala Jorquera, Antonio

    2015-01-01

    El TFG abordará el estudio de la cavitación en un tubo de Venturi de forma experimental usando para ello una instalación de laboratorio, la cual habrá que poner en funcionamiento y caracterizar mediante una serie de ensayos. Los resultados obtenidos servirán para discutir si la experimentación se corresponde con lo dictado por el modelo analítico de presiones desarrollado para la detección de la cavitación. Además, la puesta en marcha de la instalación y su caracterización serv...

  20. Importancia del hematoma en las fracturas de los hueso s largos: estudio experimental en ratas

    OpenAIRE

    Barros, T. E. P. de; Pires Camargo, O.; Guarniero, R.; Mazzariol, A. Q.; Reis, José T.A.B.; Thomazin, W. T.; Rodrigues, C.J.

    1992-01-01

    Los autores han estudiado la importancia del hematoma en la consolidación de las fracturas de los hueso s largos. Para ello, han realizado un estudio experimental en 50 ratas Wistar, en las cuales se producía una fractura a nivel de sus tibias, siendo estabilizadas posteriormente, mediante agujas intramedulares. El hematoma era aspirado del foco de fractura en el miembro derecho, mientras que el miembro izquierdo servía como control. Los animale s fueron sacrificados tras difer...

  1. Experimental Investigation of Effects of Vibration upon Elastic and Cohesive Properties of Beds of Wet Sand

    Directory of Open Access Journals (Sweden)

    S. Alsop

    1995-01-01

    Full Text Available The transmission of sinusoidal vibrations through beds of cohesive particulate solids was measured. Results were interpreted in terms of a critical state model to predict the elastic swelling constant k, and the cohesive stress C. Factorial experimental design was used to identify significant parameters. Factors that affect k include percent moisture, bulk density, sample size, sample shape, the presence of a supporting membrane, and loading order. Factors that affect C include percent moisture and particle size distribution. Factors affecting k were interpreted in terms of their effects upon bed structure and factors affecting C in terms of an equivalent pore water pressure due to capillary and liquid bridge effects. The critical state model was modified to incorporate general relationships between axial and radial strains.

  2. An Experimental and Numerical Investigation of Fluidized Bed Gasification of Solid Waste

    Directory of Open Access Journals (Sweden)

    Sharmina Begum

    2013-12-01

    Full Text Available Gasification is a thermo-chemical process to convert carbon-based products such as biomass and coal into a gas mixture known as synthetic gas or syngas. Various types of gasification methods exist, and fluidized bed gasification is one of them which is considered more efficient than others as fuel is fluidized in oxygen, steam or air. This paper presents an experimental and numerical investigation of fluidized bed gasification of solid waste (SW (wood. The experimental measurement of syngas composition was done using a pilot scale gasifier. A numerical model was developed using Advanced System for Process ENgineering (Aspen Plus software. Several Aspen Plus reactor blocks were used along with user defined FORTRAN and Excel code. The model was validated with experimental results. The study found very similar performance between simulation and experimental results, with a maximum variation of 3%. The validated model was used to study the effect of air-fuel and steam-fuel ratio on syngas composition. The model will be useful to predict the various operating parameters of a pilot scale SW gasification plant, such as temperature, pressure, air-fuel ratio and steam-fuel ratio. Therefore, the model can assist researchers, professionals and industries to identify optimized conditions for SW gasification.

  3. Experimental and Numerical Research Activity on a Packed Bed TES System

    Directory of Open Access Journals (Sweden)

    Mario Cascetta

    2016-09-01

    Full Text Available This paper presents the results of experimental and numerical research activities on a packed bed sensible thermal energy storage (TES system. The TES consists of a cylindrical steel tank filled with small alumina beads and crossed by air used as the heat transfer fluid. Experimental tests were carried out while varying some operating parameters such as the mass flow rate, the inlet–outlet temperature thresholds and the aspect ratio (length over diameter. Numerical simulations were carried out using a one-dimensional model, specifically developed in the Matlab-Simulink environment and a 2D axisymmetric model based on the ANSYS-Fluent platform. Both models are based on a two-equation transient approach to calculate fluid and solid phase temperatures. Thermodynamic properties were considered to be temperature-dependent and, in the Computational Fluid Dynamics (CFD model, variable porosity of the bed in the radial direction, thermal losses and the effective conductivity of the alumina beads were also considered. The simulation results of both models were compared to the experimental ones, showing good agreement. The one-dimensional model has the advantage of predicting the axial temperature distribution with a very low computational cost, but it does not allow calculation of the correct energy stored when the temperature distribution is strongly influenced by the wall. To overcome this problem a 2D CFD model was used in this work.

  4. Experimental Investigation of a Three-Bed Adsorption Refrigeration Chiller Employing an Advanced Mass Recovery Cycle

    Directory of Open Access Journals (Sweden)

    Atsushi Akisawa

    2009-07-01

    Full Text Available The performance of an advanced three-bed adsorption chiller with a mass recovery cycle has been experimentally investigated in the present study. The temperature and pressure of various components of the chiller were monitored to observe the dynamic behaviour of the chiller. The performances in terms of the coefficient of performance (COP and specific cooling power (SCP were compared with a conventional single stage. The results show that the proposed cycle produces COP and SCP values superior to those of the conventional single stage cycle for heat source temperature below 75 °C.

  5. Modeling and Experimental Studies of Mercury Oxidation and Adsorption in a Fixed-Bed Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Buitrago, Paula A.; Morrill, Mike; Lighty, JoAnn S.; Silcox, Geoffrey D.

    2009-06-15

    This report presents experimental and modeling mercury oxidation and adsorption data. Fixed-bed and single-particle models of mercury adsorption were developed. The experimental data were obtained with two reactors: a 300-W, methane-fired, tubular, quartz-lined reactor for studying homogeneous oxidation reactions and a fixed-bed reactor, also of quartz, for studying heterogeneous reactions. The latter was attached to the exit of the former to provide realistic combustion gases. The fixed-bed reactor contained one gram of coconut-shell carbon and remained at a temperature of 150°C. All methane, air, SO2, and halogen species were introduced through the burner to produce a radical pool representative of real combustion systems. A Tekran 2537A Analyzer coupled with a wet conditioning system provided speciated mercury concentrations. At 150°C and in the absence of HCl or HBr, the mercury uptake was about 20%. The addition of 50 ppm HCl caused complete capture of all elemental and oxidized mercury species. In the absence of halogens, SO2 increased the mercury adsorption efficiency to up to 30 percent. The extent of adsorption decreased with increasing SO2 concentration when halogens were present. Increasing the HCl concentration to 100 ppm lessened the effect of SO2. The fixed-bed model incorporates Langmuir adsorption kinetics and was developed to predict adsorption of elemental mercury and the effect of multiple flue gas components. This model neglects intraparticle diffusional resistances and is only applicable to pulverized carbon sorbents. It roughly describes experimental data from the literature. The current version includes the ability to account for competitive adsorption between mercury, SO2, and NO2. The single particle model simulates in-flight sorbent capture of elemental mercury. This model was developed to include Langmuir and Freundlich isotherms, rate equations, sorbent feed rate, and

  6. Experimental studies on pulp and paper mill sludge ash behavior in fluidized bed combustors

    Energy Technology Data Exchange (ETDEWEB)

    Latva-Somppi, J. [VTT Chemical Technology, Espoo (Finland). Process Technology

    1998-11-01

    Ash formation during the fluidized bed combustion (FBC) of pulp and paper mill sludges has been experimentally studied on an industrial and bench scale. The methods included aerosol measurements, chemical and crystalline composition analyses, thermogravimetry and electron microscopy. Fly ash mass and number size distributions and elemental enrichment in submicron particles and bottom ash were measured. Fly ash, bottom ash and ash deposits were characterized and their formation mechanisms are discussed. During combustion the fine paper-making additives in sludge, clay minerals and calcite, sintered fanning porous agglomerates. The fly ash mass mean size was 7.5 - 15 lam and the supermicron particles included 93.6 - 97.3 % of the fly ash. Condensation of the volatilized inorganic species formed spherical submicron particles in the fly ash. Their mass concentration was almost negligible when co-firing paper mill sludges and wood. This suggests that the fraction of the volatilized inorganic species in the paper mill sludges was low. Results from pulp mill sludge and bark co-firing were different. A clear mass mode below 0.3 pm, presenting 2.2 - 5.0 weight-% of the fly ash was detected. The condensed species included K, Na, S and Cl. Their mass fraction was higher in the pulp mill sludge than in the paper mill sludge. Evidently this resulted in increased volatilization and formation of condensed particles. The following trace elements were enriched in the submicron ash during pulp mill sludge and wood co-firing: As, Cd, Rb and Pb. The main part of the volatile species was, however, captured in the bulk ash. Presumably, this was due to the high surface area concentration in the bulk ash. Sludge moisture was observed to reduce the inorganic species volatilization. Probably steam vaporization from the wet sludge through the burning layer decreased combustion temperatures on char surface and less char was produced. Hence, the volatilization of ash forming species was

  7. Estudio clínico-experimental de un fóbico: estudios de psicología de szondi

    OpenAIRE

    2012-01-01

    Continuamos nuestros estudios sobre las estructuras instintivas profundas, según las doctrinas y métodos del Análisis del Destino, del eminente heredo-psiquiatra, psicoanalista y psicoterapeuta Dr. L. Szondi. El caso que hoy presentamos es una muestra de la combinación efectiva entre los métodos clínicos, bioeléctricos y psicológicos. Por el empleo sistemático de estos métodos conjugados en la comprensión adecuada de los pacientes mentales, la clínica se coloca en mejores condiciones para un ...

  8. Experimental evidence of statistical ensemble behavior in bed load sediment transport

    Science.gov (United States)

    Fathel, Siobhan L.; Furbish, David Jon; Schmeeckle, Mark W.

    2015-11-01

    A high-resolution data set obtained from high-speed imaging of coarse sand particles transported as bed load allows us to confidently describe the forms and qualities of the ensemble distributions of particle velocities, accelerations, hop distances, and traveltimes. Autocorrelation functions of frame-averaged values (and the decay of these functions) support the idea that the forms of these distributions become time invariant within the 5 s imaging interval. Distributions of streamwise and cross-stream particle velocities are exponential, consistent with previous experiments and theory. Importantly, streamwise particle velocities possess a "light" tail, where the largest velocities are limited by near-bed fluid velocities. Distributions of streamwise and cross-stream particle accelerations are Laplace in form and are centered on zero, consistent with equilibrium transport conditions. The majority of particle hops, measured start to stop, involve short displacements, and streamwise hop distances possess a Weibull distribution. In contrast to previous work, the distribution of traveltimes is exponential, consistent with a fixed temporal disentrainment rate. The Weibull distribution of hop distances is consistent with a decreasing spatial disentrainment rate and is related to the exponential distribution of traveltimes. By taking into account the effects of experimental censorship associated with a finite sampling window, the relationship between streamwise hop distances and traveltimes, Lx˜Tpα, likely involves an exponent of α ˜ 2. These experimental results—an exponential distribution of traveltimes Tp and a Weibull distribution of hop distances Lx with shape parameter k 1.

  9. EXPERIMENTAL STUDY ON BED-LOAD SEDIMENT TRANSPORT IN IRREGULAR WAVE-CURRENT COEXISTENT FIELD

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In order to evaluate bed-load sediment transport in an irregular wave-current coexistent field, a series of experiments were completed in laboratory with an irregularly oscillating tray, which was specially designed to simulate the irregular wave-current coexistent field. Experimental results are presented on the initial motion of sediment and the rates of transport over flat horizontal bed. Testing conditions included three interaction angles, 0°, 45°, 90° and six kinds of grain sizes. Four kinds (0.2mm, 0.46mm, 0.85mm and 1.3mm) were used for the tests of initial motion, while the other two kinds (0.38mm and 1.1mm) for the tests of transport rate. Comparisons between experimental results of initial motion and modified Shields curve indicate that the Shields curve is still valid for the case of irregular wave-current coexistent field. Analysis of flow regime shows that initial conditions fall within smooth-turbulent transitional region. The results of transport rate show us that net sediment transport rate can be expressed approximately as the function of the maximum bottom shear stress and mean shear stress. A dimensionless formula is proposed on the basis of mechanism "Waves erode sediments, tides transport sediments".

  10. An Experimental Investigation on Solid Acceleration Length in the Riser of a Long Circulating Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Systematic experimental work was conducted to investigate the solid acceleration length in a 16m long circulating fluidized bed riser with fluid cracking catalyst particles over a wide range of operating conditions. A more feasible method is proposed to determine the acceleration length from the measured axial profiles of pressure gradient (or apparent solid holdup). With this new method and large amount of experimental data, a clear picture on the variation of the acceleration length with both solid circulating rate and superficial gas velocity is obtained.It is found that the acceleration length increases generally with increasing solid flow rate and/or decreasing gas velocity. However, the trend in variation of the acceleration length with operating conditions are quite different in different operation ranges. Reasonable explanations are suggested for the observed variation patterns of acceleration length.

  11. Experimental investigation of CO{sub 2} capture using sodium hydroxide particles in a fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Naeem, Sareh; Ghaemi, Ahad; Shahhosseini, Shahrokh [Iran University of Science and Technology (IUST), Tehran (Iran, Islamic Republic of)

    2016-04-15

    CO{sub 2} capture from air using sodium hydroxide solid sorbent in a laboratory scale fluidized bed reactor was investigated experimentally. The influence of three parameters of temperature, inlet CO{sub 2} volume percentage and inlet air flow rate on the CO{sub 2} removal rate was studied. Experimental results showed that the optimum rate was at 25 oC when the inlet CO{sub 2} volume percentage was 1%. The results also showed that the adsorption process was reactive, and the reaction mechanism depended on the reaction temperature. In addition, empirical observation revealed only one adsorption cycle happened at low temperatures (25-30 oC). As the temperature increased, the second adsorption cycle occurred and, finally, CO{sub 2} desorption cycle took place in the range of 90-115 .deg. C.

  12. Co-gasification of Colombian coal and biomass in fluidized bed: An experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Jhon F. Velez; Farid Chejne; Carlos F. Valdes; Eder J. Emery; Carlos A. Londono [Universidad Nacional de Colombia, Antioquia (Colombia). Grupo de Termodinamica Aplicada y Energias Alternativas

    2009-03-15

    The main results of an experimental work on co-gasification of Colombian biomass/coal blends in a fluidized bed working at atmospheric pressure are reported in this paper. Several samples of blends were prepared by mixing 6-15wt% biomass (sawdust, rice or coffee husk) with coal. Experimental assays were carried out by using mixtures of different steams/blends (Rvc) and air/blend (Rac) ratios showing the feasibility to implement co-gasification as energetic alternative to produce fuel gas to heat and to generate electricity and the possibility of converting clean and efficiently the refuse coal to a low-heating value gas. 29 refs., 5 figs., 4 tabs.

  13. Cleaning of porous filters in fossilized bed reactors; Estudio de limpieza de filtros porosos en reactores de lecho fluidizado

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigo Otero, A.; Sancho Rod, J.

    1965-07-01

    In this report are established the optimum working conditions of a filter cleaning system by blow back. For this purpose it was determined in the first place the blow back air rate necessary to have a good cleaning. The reasons for which it was not possible until now to control the pressure in a fluidized bed calcination reactor are analyzed and a criteria is established to calculate the optimum floe necessary to clean efficiently a porous by this procedures. (Author)

  14. Breakthrough behavior of granular ferric hydroxide (GFH) fixed-bed adsorption filters: modeling and experimental approaches.

    Science.gov (United States)

    Sperlich, Alexander; Werner, Arne; Genz, Arne; Amy, Gary; Worch, Eckhard; Jekel, Martin

    2005-03-01

    Breakthrough curves (BTC) for the adsorption of arsenate and salicylic acid onto granulated ferric hydroxide (GFH) in fixed-bed adsorbers were experimentally determined and modeled using the homogeneous surface diffusion model (HSDM). The input parameters for the HSDM, the Freundlich isotherm constants and mass transfer coefficients for film and surface diffusion, were experimentally determined. The BTC for salicylic acid revealed a shape typical for trace organic compound adsorption onto activated carbon, and model results agreed well with the experimental curves. Unlike salicylic acid, arsenate BTCs showed a non-ideal shape with a leveling off at c/c0 approximately 0.6. Model results based on the experimentally derived parameters over-predicted the point of arsenic breakthrough for all simulated curves, lab-scale or full-scale, and were unable to catch the shape of the curve. The use of a much lower surface diffusion coefficient D(S) for modeling led to an improved fit of the later stages of the BTC shape, pointing on a time-dependent D(S). The mechanism for this time dependence is still unknown. Surface precipitation was discussed as one possible removal mechanism for arsenate besides pure adsorption interfering the determination of Freundlich constants and D(S). Rapid small-scale column tests (RSSCT) proved to be a powerful experimental alternative to the modeling procedure for arsenic.

  15. Parametric experimental tests of steam gasification of pine wood in a fluidized bed reactor

    Directory of Open Access Journals (Sweden)

    L. Vecchione

    2013-09-01

    Full Text Available Among Renewable Energy Sources (RES, biomass represent one of the most common and suitable solution in order to contribute to the global energy supply and to reduce greenhouse gases (GHG emissions. The disposal of some residual biomass, as pruning from pine trees, represent a problem for agricultural and agro-industrial sectors. But if the residual biomass are used for energy production can become a resource. The most suitable energy conversion technology for the above-mentioned biomass is gasification process because the high C/N ratio and the low moisture content, obtained from the analysis. In this work a small-pilot bubbling-bed gasification plant has been designed, constructed and used in order to obtain, from the pine trees pruning, a syngas with low tar and char contents and high hydrogen content. The activities showed here are part of the activities carried out in the European 7FP UNIfHY project. In particular the aim of this work is to develop experimental test on a bench scale steam blown fluidized bed biomass gasifier. These tests will be utilized in future works for the simulations of a pilot scale steam fluidized bed gasifier (100 kWth fed with different biomass feedstock. The results of the tests include produced gas and tar composition as well gas, tar and char yield. Tests on a bench scale reactor (8 cm I.D. were carried out varying steam to biomass ratio from 0.5, 0.7 and 1 to 830°C.

  16. Experimental and predicted approaches for biomass gasification with enriched air-steam in a fluidised bed.

    Science.gov (United States)

    Fu, Qirang; Huang, Yaji; Niu, Miaomiao; Yang, Gaoqiang; Shao, Zhiwei

    2014-10-01

    Thermo-chemical gasification of sawdust refuse-derived fuel was performed on a bench-scale fluidised bed gasifier with enriched air and steam as fluidising and oxidising agents. Dolomite as a natural mineral catalyst was used as bed material to reform tars and hydrocarbons. A series of experiments were carried out under typical operating conditions for gasification, as reported in the article. A modified equilibrium model, based on equilibrium constants, was developed to predict the gasification process. The sensitivity analysis of operating parameters, such as the fluidisation velocity, oxygen percentage of the enriched air and steam to biomass ratios on the produced gas composition, lower heating value, carbon conversion and cold gas efficiency was investigated. The results showed that the predicted syngas composition was in better agreement with the experimental data compared with the original equilibrium model. The higher fluidisation velocity enhanced gas-solid mixing, heat and mass transfers, and carbon fines elutriation, simultaneously. With the increase of oxygen percentage from 21% to 45%, the lower heating value of syngas increased from 5.52 MJ m(-3) to 7.75 MJ m(-3) and cold gas efficiency from 49.09% to 61.39%. The introduction of steam improved gas quality, but a higher steam to biomass ratio could decrease carbon conversion and gasification efficiency owing to a low steam temperature. The optimal value of steam to biomass ratio in this work was 1.0.

  17. Design and experimental performance verification of a thermal property test-bed for lunar drilling exploration

    Institute of Scientific and Technical Information of China (English)

    Zhang Tao; Zhao Zeng; Liu Shuting; Li Jinglin; Ding Xilun; Yin Shen; Wang Guoxin; Lai Xiaoming

    2016-01-01

    Chinese Chang’e lunar exploration project aims to collect and return subsurface lunar soil samples at a minimum penetration depth of 2 m in 2017. However, in contrast to those on the Earth, automated drilling and sampling missions on the Moon raise the risk of burning bits. Test-beds are required for testing the thermal properties of drill tools in a lunar environment. In this paper, a novel temperature measuring method based on thermocouples and a slip ring was proposed. Furthermore, a data acquisition system for a drilling process was designed. A vacuous, cryogenic, and anhydrous soil environment simulating the lunar surface was established. A drilling test-bed that can reach a depth of 2.2 m was developed. A control strategy based on online monitoring signals was proposed to improve the drilling performance. Vacuum and non-vacuum experiments were performed to test the temperature rising effect on drill tools. When compared with the non-vacuum experiment, the vacuum temperature rise resulted in a 12 ?C increase. These experimental results provide significant support for Chinese lunar exploration missions.

  18. Experimental study on the bank erosion and interaction with near-bank bed evolution due to fluvial hydraulic force

    Institute of Scientific and Technical Information of China (English)

    Ming-hui YU; Hong-yan WEI; Song-bai WU

    2015-01-01

    Bank erosion is a typical process of lateral channel migration, which is accompanied by vertical bed evolution. As a main sediment source, the failed bank soil may directly cause the increase of sediment concentration and considerable channel evolution in a short time. The paper presents an experimental study on non-cohesive and cohesive homogenous bank failure processes, influence of the failed bank soil on bank re-collapse, as well as the interaction between bank failure and near-bank bed evolution due to fluvial hydraulic force. A series of experiments were carried out in a 180° bend rectangular flume. The results reveal the iteration cycle between bank erosion and bed deformation: undercutting of the riverbank, slip failure of the submerged zone of the bank, as well as cantilever failure of the overhang, failed bank soil staying at bank toe temporarily or hydraulic transportation, exchange between the failed bank soil and bed material, bed material load being re-transported either as bed load or as suspended load, and bed deformation. Same as bank failure, the mixing of failed bank soil and bed material is more severe near the curved flow apex. Moreover, non-cohesive bank failure tends to occur near the water surface while cohesive bank failure near the bank toe. For non-cohesive dense (sandy) soil, the bank erosion amount and residual amount of failed bank soil on the bed increase with the near-bank velocity or bed erodibility. But for cohesive soil, only bank erosion amount follows the above rule. The results are expected to provide theoretical basis for river management and flood prevention.

  19. Granular-bed Filtration Assisted by Filter Cake Formation: Advanced Design and Experimental Verification

    Energy Technology Data Exchange (ETDEWEB)

    Gaarder, Kavitha Pathmanathan

    2011-07-01

    Particulate matter removal at high temperatures has gained a great attention in the last years due to the vast growing of power production plants around the world. A reliable and robust gas cleaning method is inherently necessary to facilitate efficient fuel to energy conversion while protecting all the downstream equipment s in a plant. In accordance with the current demand, a detail study has been conducted on panel bed filter which exhibits the suitable characteristic for high temperature applications.The thesis focuses on four main parts related to the design evaluation, experimental verification and development of new apparatus and method for regeneration in a panel bed filter. The four main parts are as following;1. Testing of an advanced new louver design, filter tray, at room and elevated temperature 2. Development of a new apparatus and method for puff-back cleaning 3. Testing of filter tray with the new puff-back apparatus and 4. Industrial scale panel bed filter testing in a commercial combustion plant. A very first laboratory scale panel bed filter with filter tray louvers was built and tested at room temperature. Tests were performed mainly at higher filtration velocities (7 - 31cm/s) with sintered bauxite spherical particles (mean diameter of 710 m) as filtration medium with standardized test dust (mean diameter of 9 m). The filter demonstrated excellent results at filtration velocity of 30 cm/s however unstable residual pressure drop profile and high dust penetration were recorded, suggesting the depth of the granular beds are too shallow. A second laboratory scale panel-bed filter with filter tray louvers with deeper granular beds, i.e. 40 mm was built. The gas-entry surfaces are much larger than the first test rig. Tests were performed from low to high filtration velocities with sintered bauxite spherical particles (mean diameter of 470 and 710 m) and olivine sand particles (mean diameter of 545 m) as filtration medium and standardized test dust

  20. Experimental researches on mass and heat transfer in new typical cross-flow rotating packed bed

    Institute of Scientific and Technical Information of China (English)

    CHEN Haihui; ZENG Yingying; GAO Wenshuai

    2006-01-01

    New typical cross-flow Rotating Packed Bed(RPB)called multi-pulverizing RPB was manufactured.There is enough void in multi-pulverizing RPB,where liquid easily flows and is repeatedly pulverized by light packing,which decreases the material consumed,lightens the weight,and compacts the structure.Mass and heat transfer property in the new type PRB were studied by two experimental models.In the mass transfer model,the axial fan pumping gas press is only 100 Pa,mass transfer coefficient and volumetric mass transfer coefficient are similar to countercurrent RPB,which are an order quantity lager than that in the conventional packed tower.In the heat transfer experiment,the axial fan pumping gas press is only 120 Pa;volumetric heatwhich especially suits the treatment of large gas flow and lower gas pressure drop.

  1. CO2 Absorption in a Lab-Scale Fixed Solid Bed Reactor: Modelling and Experimental Tests

    Directory of Open Access Journals (Sweden)

    Roberto Gabbrielli

    2004-09-01

    Full Text Available The CO2 absorption in a lab-scale fixed solid bed reactor filled with different solid sorbents has been studied under different operative conditions regarding temperature (20-200°C and input gas composition (N2, O2, CO2, H2O at 1bar pressure. The gas leaving the reactor has been analysed to measure the CO2 and O2 concentrations and, consequently, to evaluate the overall CO2 removal efficiency. In order to study the influence of solid sorbent type (i.e. CaO, coal bottom ash, limestone and blast furnace slag and of mass and heat transfer processes on CO2 removal efficiency, a one-dimensional time dependent mathematical model of the reactor, which may be considered a Plug Flow Reactor, has been developed. The quality of the model has been confirmed using the experimental results.

  2. Virtual experimentation through 3D full-loop simulation of a circulating fluidized bed

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Eulerian granular multiphase model with a drag coefficient correction based on the energy-minimization multi-male (EMMS) model was used to simulate a semi-industry scale circulating fiuidized bed (CFB).Three-dimensional(3D), time-dependent simulation of a full-loop CFB revealed that the axial profiles of cross-sectionally averaged solid volume fraction,and the radial profiles of solid axial velocity and solid volume fraction were in reasonable agreement with experimental data.Based on this agreement,database derived from experiments not yet accomplished was replenished with such simulations, and fluid regime diagrams and pressure balance around the CFB loop were derived accordingly. This work presents an integrated viewpoint on CFB and unfolds a fresh paradigm fur CFB modeling, which can be expected to help resolve certain issues long in dispute but hard for experiments.

  3. Modelo experimental en el estudio de posibles principios activos antipalúdicos

    Directory of Open Access Journals (Sweden)

    Nelly Incio V

    2006-07-01

    Full Text Available Objetivo: Contribuir a desarrollar un modelo experimental de bajo costo y con menor riesgo, evitando el empleo de suero humano, para el cultivo continuo de Plasmodium falciparum en eritrocitos humanos para estudios iniciales de plantas medicinales con probable acción antipalúdica. Materiales y métodos: Se siguió, en lo fundamental, la técnica descrita de Trager y Jensen, con pequeñas modificaciones como no emplear sangre heparinizada ni suero humano. En frascos de cultivo celular el paquete globular fue resuspendido en RPMI 1640 suplementado con Medium hepes y suero fetal bovino inactivado. La muestra de P. falciparum en un criotubo fue finalmente sembrada. El cultivo continuo fue enfrentado con el extracto acuoso de Bixa orellana (achiote. Resultados: Obtenidos los cultivos de eritrocitos sin contaminación, la propagación del P. falciparum demoró alrededor de 60 días. El extracto de B. Orellana produjo lisis de los eritrocitos parasitados, obteniendo similar resultado con el estándar sulfato de quinina. Conclusiones: Se logró desarrollar un modelo experimental simple, de poco riesgo por no emplear suero humano, para cultivo continuo de P. falciparum, con posibilidades en la exploración de plantas de empleo antipalúdico tradicional.

  4. Estudios de economía y cooperación social. Un estudio experimental con estudiantes universitarios en Chile

    Directory of Open Access Journals (Sweden)

    Javier Núñez

    2009-01-01

    Full Text Available Este artículo aporta nuevas pruebas experimentales del efecto de estudiar economía en dos dimensiones de la cooperación social: la confianza y la reciprocidad. Estas dimensiones son aproximadas por medio del conocido juego de confianza. Empleando técnicas de muestreo e igualación (matching, y un reclutamiento de sujetos por invitación selectiva en vez de convocatoria abierta, el trabajo permite separar el efecto asociado al estudio de la economía del efecto asociado al potencial sesgo de selección en las preferencias de quienes escogen estudiar economía. La muestra está compuesta por estudiantes universitarios de economía y de otras carreras con escaso o nulo contenido de economía en Chile. Los resultados muestran que los montos enviados por los estudiantes de economía en la primera etapa del juego de confianza son significativamente menores en comparación con los estudiantes de otras carreras, lo que indica una menor propensión de los primeros a confiar en los demás. A su vez, encontramos una menor inclinación de los economistas a devolver los montos prometidos, lo que muestra una menor tendencia a la reciprocidad de la confianza depositada en ellos en el juego de confianza.

  5. Experimental study of depth-limited open-channel flows over a gravel bed

    Institute of Scientific and Technical Information of China (English)

    Cheng Zeng; Chiwai Li; Hongwu Tang; Lingling Wang; Jingqiao Mao

    2015-01-01

    abstract Laboratory experiments of depth-limited open-channel flows over a gravel bed were conducted in the study. Two gravel patches with identical individual element size and different lengths (3.81 m and 7.5 m) were tested. The depth-limited uniform flow regime with relative submergence Sr ( ¼ D/ks) ranging from 2.68 to 5.94 was produced by adjusting the tailgate weir. The velocity profiles were measured by using both an ultra-sound velocity profiler (UVP) and an acoustic Doppler velocimeter (ADV). The conventional methods used to determine the zero-plane displacement and estimate the bed shear velocity were then reviewed and compared. The measured double-averaged (DA) velocity profiles were found to fit well with the log law and defect law with a non-universal Karman constantκ.κ-value remains nearly constant and in the range from 0.2 to 0.3 for the long patch (LP) cases andκ-values are scattered within a wider range from 0.3 to 0.5 for the short patch (SP) cases. While the Br-value in log law remains constant and equal to 8.5 for LP cases, the Br-value was found to decrease with the increase of the dimensionless roughness height ksþ for SP cases. The streamwise turbulence intensity distributions were found to be independent on the patch length and agree well with the available experimental data in the intermediate region and wall region. The Manning resistance coefficient and Darcy–Weisbach friction factor were analyzed. Theκ-value decreases to 0.22 for the fitting of the logarithmic flow resistance law under small relative submergence. The value of the integration constant Ar in the logarithmic law falls within the normal range between 3.25 and 6.25.

  6. ESTUDIO TEORICO EXPERIMENTAL DEL FENOMENO DE MIGRACION ESPECIFICA EN MATERIALES POLIMERICOS UTILIZADOS EN EL ENVASADO DE ALIMENTOS

    OpenAIRE

    TORRES MEDIANO; ALEJANDRA

    2011-01-01

    El proceso de transferencia de masa de componentes desde los envases hacia los alimentos determina la calidad sensorial y el grado de inocuidad del producto envasado. El presente estudio está enfocado a un análisis teórico-experimental del fenómeno de migración específica, utilizando diferentes tipos de simulantes de alimentos, considerando además el efecto de la concentración de migrante, el espesor de los films plásticos y la temperatura. La metodología del estudio comprende anális...

  7. Study of Influence of Experimental Technique on Measured Particle Velocity Distributions in Fluidized Bed

    Science.gov (United States)

    Gopalan, Balaji; Shaffer, Frank

    2013-11-01

    Fluid flows that are loaded with high concentration of solid particles are common in oil and chemical processing industries. However, the opaque nature of the flow fields and the complex nature of the flow have hampered the experimental and computational study of these processes. This has led to the development of a number of customized experimental techniques for high concentration particle flows for evaluation and improvement of CFD models. This includes techniques that track few individual particles, measures average particle velocity over a small sample volume and those over a large sample volume. In this work novel high speed PIV (HsPIV), with individual particle tracking, was utilized to measure velocities of individual particles in gas-particle flow fields at the walls circulating and bubbling fluidized bed. The HsPIV measurement technique has the ability to simultaneously recognize and track thousands of individual particles in flows of high particle concentration. To determine the effect of the size of the sample volume on particle velocity measurements, the PDF of Lagrangian particle velocity was compared with the PDF of Eulerian for different domain sizes over a range of flow conditions. The results will show that measured particle velocity distribution can vary from technique to technique and this bias has to be accounted in comparison with CFD simulations.

  8. Experimental implementation of automatic 'cycle to cycle' control to a nonlinear chiral simulated moving bed separation.

    Science.gov (United States)

    Grossmann, Cristian; Langel, Christian; Mazzotti, Marco; Morari, Manfred; Morbidelli, Massimo

    2010-03-26

    In order to better exploit the economic potential of the simulated moving bed chromatography a 'cycle to cycle' controller which only requires the information about the linear adsorption behavior and the overall average porosity of the columns has been proposed. Recently, an automated on-line HPLC monitoring system which determines the concentrations in the two product streams averaged over one cycle, and returns them as feedback information to the controller was implemented. The new system allows for an accurate determination of the average concentration of the product streams even if the plant is operated at high concentrations. This paper presents the experimental implementation of the 'cycle to cycle' control concept to the separation of guaifenesin enantiomers under nonlinear chromatographic conditions, i.e. at high feed concentrations. Different case studies have been carried out to challenge the controller under realistic operation conditions, e.g. introducing pump disturbances and changing the feed concentration during the operation. The experimental results clearly demonstrate that the controller can indeed deliver the specified purities and improve the process performance.

  9. Experimental Study on Coal Multi-generation in Dual Fluidized Beds

    Institute of Scientific and Technical Information of China (English)

    Fan Xiaoxu; Lu Qinggang; Na Yongjie; Liu Qi

    2007-01-01

    An atmospheric test system of dual fluidized beds for coal multi-generation was built. One bubbling fluidized bed is for gasification and a circulating fluidized bed for combustion. The two beds are combined with two valves:one valve to send high temperature ash from combustion bed to the gasification bed and another valve to send char and ash from gasification bed to combustion bed. Experiments on Shenhua coal multi-generation were made at temperatures from 1112 K to 1191 K in the dual fluidized beds. The temperatures of the combustor are stable and the char combustion efficiency is about 98%. Increasing air/coal ratio to the fluidized bed leads to the increase of temperature and gasification efficiency. The maximum gasification efficiency is 36.7% and the calorific value of fuel gas is 10.7 MJ/Nm3. The tar yield in this work is 1.5%, much lower than that of pyrolysis.Carbon conversion efficiency to fuel gas and flue gas is about 90%.

  10. The effect of an experimentally created mussel bed on bird densities and food intake of the Oystercatcher Haematopus ostralegus

    NARCIS (Netherlands)

    Ens, BJ; Alting, D

    1996-01-01

    When an experimental mussel bed was created in 1987 on the mudflats south of Schiermonnikoog, Herring Gulls immediately increased in numbers, consuming starfish and damaged Mussels. The build-up of oyster catcher numbers was more gradual, but persisted for longer. Most Oystercatchers attracted to th

  11. Gas-solid two-phase turbulent flow in a circulating fluidized bed riser: an experimental and numerical study

    NARCIS (Netherlands)

    He, Y.; Sint Annaland, van M.; Deen, N.G.; Kuipers, J.A.M.

    2006-01-01

    Hydrodynamics of gas-particle two-phase turbulent flow in a circulating fluidized bed riser is studied experimentally by Particle Image Velocimetry (PIV) and numerically with the use of a 3D discrete hard sphere particle model (DPM). Mean particle velocities and RMS velocities are obtained and the i

  12. Experimental validation of granular dynamics simulations of gas-fluidised beds with homogeneous inflow conditions using Positron Emission Particle Tracking

    NARCIS (Netherlands)

    Hoomans, B.P.B.; Kuipers, J.A.M.; Mohd Salleh, M.; Seville, J.P.

    2001-01-01

    A hard-sphere granular dynamics model of a two-dimensional gas-fluidised bed was experimentally validated using Positron Emission Particle Tracking (PEPT). In the model the Newtonian equations of motion are solved for each solid particle while taking into account the particle¿particle and particle¿w

  13. EXPERIMENTAL STUDY ON THE DYNAMICS OF A SPOUTED BED WITH PARTICLE FEED THROUGH THE BASE

    Directory of Open Access Journals (Sweden)

    Freitas L.A.P.

    1997-01-01

    Full Text Available A draft tube spouted bed was constructed with a screw conveyor attached at its base to feed particles into the column. Results on fluid dynamic characteristics and particle movement in this system are presented and discussed. Two methods of measuring the superficial air velocity in the annular region are compared. The particle velocity and recirculation rates have been determined in a half column with transparent walls. The effects of the particle feed rate, air flow rate and bed height on the spouted bed dynamics have been analysed and compared with those in the literature. Keywords: Spouted bed, continuous feed, dynamics

  14. System Identification for Experimental Study for Polymerization Catalyst Reaction in Fluidized Bed

    Directory of Open Access Journals (Sweden)

    Ahmmed Saadi Ibrehem

    2011-11-01

    Full Text Available In this work, system identification method is used to capture the reactor characteristics of production rate of polyethylene (PE based on published experimental data. The identification method is used to measure the percentage effect on the production rate of PE by measuring the effect of input factors of temperature of reaction, hydrogen concentration, and [Al]/[Ti] molar catalyst ratio. Temperature of reaction has big effects equal 52.4 % on the output of the system and 47.6 % on interaction of the system's parameters compare to other two factors. Also, hydrogen concentration has big effect equal 45.66 % on the output of the system and 14.7 % on interaction of the system's parameters. [Al]/[Ti] molar catalyst ratio has big effect on interaction of the system equal 28.6 and 1.94 % on the output of the system but less than the reaction temperature and hydrogen concentration. All these results depend on experiment results and these results are very important in industrial plants. ©2011 BCREC UNDIP. All rights reserved(Received: 13rd May 2011; Revised: 27th July 2011; Accepted: 22th September 2011[How to Cite: Ahmmed S. Ibrehem. (2011. System Identification for Experimental Study for Polymerization Catalyst Reaction in Fluidized Bed. Bulletin of Chemical Reaction Engineering & Catalysis, 6 (2: 137-146. doi:10.9767/bcrec.6.2.874.137-146][How to Link / DOI: http://dx,doi.org/10.9767/bcrec.6.2.874.137-146 || or local:  http://ejournal.undip.ac.id/index.php/bcrec/article/view/874 ] | View in 

  15. Multi-Column Experimental Test Bed for Xe/Kr Separation

    Energy Technology Data Exchange (ETDEWEB)

    Greenhalgh, Mitchell Randy [Idaho National Lab. (INL), Idaho Falls, ID (United States); Garn, Troy Gerry [Idaho National Lab. (INL), Idaho Falls, ID (United States); Welty, Amy Keil [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lyon, Kevin Lawrence [Idaho National Lab. (INL), Idaho Falls, ID (United States); Watson, Tony Leroy [Idaho National Lab. (INL), Idaho Falls, ID (United States)ry

    2015-08-31

    Previous research studies have shown that INL-developed engineered form sorbents are capable of capturing both Kr and Xe from various composite gas streams. The previous experimental test bed provided single column testing for capacity evaluations over a broad temperature range. To advance research capabilities, the employment of an additional column to study selective capture of target species to provide a defined final gas composition for waste storage was warranted. The second column addition also allows for compositional analyses of the final gas product to provide for final storage determinations. The INL krypton capture system was modified by adding an additional adsorption column in order to create a multi-column test bed. The purpose of this modification was to investigate the separation of xenon from krypton supplied as a mixed gas feed. The extra column was placed in a Stirling Ultra-low Temperature Cooler, capable of controlling temperatures between 190 and 253K. Additional piping and valves were incorporated into the system to allow for a variety of flow path configurations. The new column was filled with the AgZ-PAN sorbent which was utilized as the capture medium for xenon while allowing the krypton to pass through. The xenon-free gas stream was then routed to the cryostat filled with the HZ-PAN sorbent to capture the krypton at 191K. Selectivities of xenon over krypton were determined using the new column to verify the system performance and to establish the operating conditions required for multi-column testing. Results of these evaluations verified that the system was operating as designed and also demonstrated that AgZ-PAN exhibits excellent selectivity for xenon over krypton in air at or near room temperature. Two separation tests were performed utilizing a feed gas consisting of 1000 ppmv xenon and 150 ppmv krypton with the balance being made up of air. The AgZ-PAN temperature was held at 295 or 253K while the HZ-PAN was held at 191K for both

  16. Estimation of particle concentration profiles in a three-phase fluidized bed from experimental data and using the wake model

    Directory of Open Access Journals (Sweden)

    Knesebeck A.

    2004-01-01

    Full Text Available Particles with a size distribution in the range of 34 to 468 µm were fluidized in a three-phase bed using low liquid and gas velocities. Particle size distribution and pressure profile measurements were carried out at different locations in the bed in order to study the influence of fluid velocities on segregation and dispersion of particles in different size classes. The influence of gas velocity on particle mixing was analyzed in terms of internal solid fluxes, calculated by means of the wake model. Based on the experimental results, different particle distribution patterns were identified. Although no significant tendencies were observed for radial profiles, particles of different sizes have significantly different axial profiles, which are mainly affected by the velocity of the liquid phase. Thus, depending on the liquid velocity, smaller particles reach a maximum concentration at different bed heights.

  17. EXPERIMENTAL STUDY ON BED SCOUR IN A 90°CHANNEL BEND

    Institute of Scientific and Technical Information of China (English)

    Masoud GHODSIAN; S. Kamal MOUSAVI

    2006-01-01

    The special feature of bend flow leads to scouring of the bed and bank. Various parameters like flow depth, flow velocity or discharge, geometry of bend and characteristics of bed material may affect the scour process. Experiments were carried out to study the effect of some important parameters on bend scour under clear water condition. Experiments were conducted in a 0.6m wide and 0.7m high flume with 90 degree bend. The lateral variations of bed slope were studied. The maximum depth of scour was correlated to densimetric Froude number, relative bend radius and relative depth of flow.

  18. Experimental study and Monte Carlo modeling of object motion in a bubbling fluidized bed

    OpenAIRE

    García Gutiérrez, Luis Miguel

    2016-01-01

    Fluidized beds are employed for a wide variety of applications such as drying, coating of particles, catalytic reactions, or thermal conversion processes. In a number of these applications, objects differing in density and/or size from the dense phase material are found in the bed. These objects can be agglomerates, catalysts or reactants. In this PhD thesis, a fundamental study of the motion of objects is presented, but considering also the main characteristics of the thermal ...

  19. Experimental and Numerical Investigation of Enhancement of Heat and Mass Transfer in Adsorbent Beds

    Institute of Scientific and Technical Information of China (English)

    LiuZhenyan; FuZhumantffu

    1994-01-01

    Some interrelated parameters of heat and mass transfer in two phases of pressure rise and constant pressure are obtained by studying the desorption processes of two kinds of cylindrical adsorbent beds.with fins and without fins.Moreover,the effects of equivalent thermal conductivity of adsorbent beds,contact thermal transfer coefficient,heat transfer of fins,condensation temperature,uncondensable gas in the adsorber are analyzed.finally,enhancement of heat and mass transfer has been attained.

  20. Analysis of the laser powder bed fusion additive manufacturing process through experimental measurement and finite element modeling

    Science.gov (United States)

    Dunbar, Alexander Jay

    The objective in this work is to provide rigourous experimental measurements to aid in the development of laser powder bed fusion (LPBF) additive manufacturing (AM). A specialized enclosed instrumented measurement system is designed to provide in situ experimental measurements of temperature and distortion. Experiments include comparisons of process parameters, materials and LPBF machines. In situ measurements of distortion and temperature made throughout the build process highlight inter-layer distortion effects previously undocumented for laser powder bed fusion. Results from these experiments are also be implemented in the development and validation of finite element models of the powder bed build process. Experimental analysis is extended from small-scale to larger part-scale builds where experimental post-build measurements are used in analysis of distortion profiles. Experimental results provided from this study are utilized in the validation of a finite element model capable of simulating production scale parts. The validated finite element model is then implemented in the analysis of the part to provide information regarding the distortion evolution process. A combination of experimental measurements and simulation results are used to identify the mechanism that results in the measured distortion profile for this geometry. Optimization of support structure primarily focuses on the minimization of material use and scan time, but no information regarding failure criteria for support structure is available. Tensile test samples of LPBF built support structure are designed, built, and tested to provide measurements of mechanical properties of the support structure. Experimental tests show that LPBF built support structure has only 30-40% of the ultimate tensile strength of solid material built in the same machine. Experimental measurement of LPBF built support structure provides clear failure criteria to be utilized in the future design and implementation of

  1. Estudio experimental sobre diferentes métodos de osteosíntesis del raquis dorsolumbar

    OpenAIRE

    Fuster Obregón, Salvador

    1987-01-01

    1) INTRODUCCIÓN Hemos estudiado los traumatismos de la columna dorsolumbar basándonos en los estudios biomecánicos de Junghans 1931, Rolander 1966, Farfan 1970 y White y Panjabi 1978, entre otros. Definimos la inestabilidad ajustándonos a los criterios de White y Panjabi 1978, y las clasificamos según Denis 1984. Estadísticas diversas concuerdan con el estudio de Laborde y cols. 1980, aceptando que la inmensa mayoría de las fracturas son por flexión y no se acompañan de déficits neurológi...

  2. A numerical model of the deep-bed drying of extruded fish feed and its experimental validation

    DEFF Research Database (Denmark)

    Haubjerg, Anders Fjeldbo; Veje, Christian; Jørgensen, Bo Nørregaard;

    A deep bed drying model for the description of moisture and temperature on an individual pellet level has been developed. Experimental validation is carried out in a special designed lab batch dryer, based on recordings of average moisture content and pellet surface temperature, on the air exhaus...... side. The model comprise empirical recording of moisture desorption isotherms and semi-empirical relations for moisture diffusivity and heat and mass transfer coefficients, in particular including the effect of air temperature on moisture diffusivity.......A deep bed drying model for the description of moisture and temperature on an individual pellet level has been developed. Experimental validation is carried out in a special designed lab batch dryer, based on recordings of average moisture content and pellet surface temperature, on the air exhaust...

  3. Evaluation of ammonium adsorption in biochar-fixed beds for treatment of anaerobically digested swine slurry: Experimental optimization and modeling.

    Science.gov (United States)

    Kizito, Simon; Wu, Shubiao; Wandera, Simon Mdondo; Guo, Luchen; Dong, Renjie

    2016-09-01

    Fixed-bed column experiments were performed to investigate the effect of influent concentration, flow rate, and adsorbent bed depth on ammonium adsorption from anaerobically digested swine slurry using three types of biochar made from corncobs (MCB), hardwood (WB), and mixed sawdust pellets (MSB). WB performed better than the other two biochar types with a maximum sorption capacity of 67-114mg/g due to its superior surface area and larger pore volume. Ammonium adsorption kinetics and dynamics depended on the influent NH4(+)-N concentration, applied inflow flow rate, and the depth of the fixed bed. Maximum sorption capacities under influent NH4(+)-N concentration of 500mg/L, were identified to be 114.2mg/g, 108.9mg/g, and 24.7mg/g at inflow rate of 15mL/min for WB, MCB, and MSB, respectively. The data shows that using deeper beds and applying lower flow rates could be a better strategy to increase ammonium adsorption in biochar-fixed beds. Moreover, three kinetic models (Thomas, Adams-Bohart (BDST), and Yoon-Nelson) were applied to the experimental data to predict breakthrough curves and determine characteristic adsorption parameters for process design. The applied models fitted data in the order: Thomas (R(2)=0.971)>BDST (R(2)=0.960)>Yoon-Nelson (R(2)=0.940). It was concluded that ammonium adsorption in biochar-fixed beds could be an effective method for routine cyclic treatment of slurry. However, further effluent polishing is required to meet discharge requirements.

  4. Experimental investigation of fluidised bed co-combustion of meat and bone meal with coals and olive bagasse

    Energy Technology Data Exchange (ETDEWEB)

    L. Fryda; K. Panopoulos; P. Vourliotis; E. Pavlidou; E. Kakaras [National Technical University of Athens, Athens (Greece). Laboratory of Steam Boilers and Thermal Plants, School of Mechanical Engineering

    2006-09-15

    Meat and bone meal (MBM) were co-fired in a laboratory scale fluidised bed combustion (FBC) apparatus together with three different primary fuels: two coal types and olive bagasse residues. Several two component fuel blends were tested under different combustion conditions to study how primary fuel substitution by MBM affects flue gas emissions as well as fluidised bed (FB) agglomeration tendency. MBM, being a highly volatile fuel, caused significant increase of CO emissions and secondary air should be used in industrial scale applications to conform to regulations. The high N-content of MBM is moderately reflected on the increase of nitrogen oxides emissions, which are reduced by MBM derived volatiles. The MBM ash, although containing bone material rich in Ca, did not create any noteworthy desulphurisation effect. The observed slight decrease in SO{sub 2} emissions is predominantly attributed to the lower sulphur content in the coal/MBM fuel mixtures. The experimental work is evaluated with bed agglomeration indices from literature. The SEM/EDS analysis of bed material samples from the coal/MBM tests revealed the formation of conglomerates of bed material debris and ash with sizes that do not greatly exceed the original bed inventory and thus are not problematic. On the contrary, the co-combustion tests of olive bagasse residues with MBM led to a prompt loss of fluidisation, as a consequence of the high potassium and silicon content of the olive bagasse, the chlorine contents in both MBM and olive bagasse, and the high phosphorus content in the MBM also forming eutectics with potassium. 44 refs., 17 figs., 5 tabs.

  5. Experimental coupling and modelling of wet air oxidation and packed-bed biofilm reactor as an enhanced phenol removal technology.

    Science.gov (United States)

    Minière, Marine; Boutin, Olivier; Soric, Audrey

    2017-01-25

    Experimental coupling of wet air oxidation process and aerobic packed-bed biofilm reactor is presented. It has been tested on phenol as a model refractory compound. At 30 MPa and 250 °C, wet air oxidation batch experiments led to a phenol degradation of 97% and a total organic carbon removal of 84%. This total organic carbon was mainly due to acetic acid. To study the interest of coupling processes, wet air oxidation effluent was treated in a biological treatment process. This step was made up of two packed-bed biofilm reactors in series: the first one acclimated to phenol and the second one to acetic acid. After biological treatment, phenol and total organic carbon removal was 99 and 97% respectively. Thanks to parameters from literature, previous studies (kinetic and thermodynamic) and experimental data from this work (hydrodynamic parameters and biomass characteristics), both treatment steps were modelled. This modelling allows the simulation of the coupling process. Experimental results were finally well reproduced by the continuous coupled process model: relative error on phenol removal efficiency was 1 and 5.5% for wet air oxidation process and packed-bed biofilm reactor respectively.

  6. DEVELOPMENT OF AN EXPERIMENTAL TEST BED DESIGNATED FOR MODEL STUDIES OF AERODYNAMICS OF PREMISES USING METHOD OF DIGITAL FLOW VISUALIZATION

    Directory of Open Access Journals (Sweden)

    Varapaev Vladimir Nikolaevich

    2012-12-01

    Full Text Available In the article, the authors present their findings generated at the laboratory of aerodynamic and aero-acoustic testing of structural units of MGSU. The authors provide information about the principle of operation and a brief description of the experimental test bed designated for the physical research of patterns of air flows arising inside building premises of various geometric shapes. The authors also demonstrate the basic parameters of the test bed, the principle of operation of its recording devices and some of its characteristics. The test bed is designated for the identification of characteristics of three-dimensional flows of models under research and for the verification of results of numerical studies. The measurement bed has advanced measurement and registration units. The management principle is based on the method of digital flow visualization, PIV method and Doppler flow meter implemented in the LDA anemometer. The test stand generates two or three component vector fields of turbulent gas flow velocities. It may be applicable to the study of liquids in case of research of hydraulics-related problems. Some results of the flow study are provided in the article, as well.

  7. Experimental study on temperature profile of fixed - bed gasification of oil-palm fronds

    Science.gov (United States)

    Atnaw, Samson M.; Sulaiman, Shaharin A.; Moni, M. Nazmi Z.

    2012-06-01

    Currently the world's second largest palm oil producer Malaysia produces large amount of oil palm biomass each year. The abundance of the biomass introduces a challenge to utilize them as main feedstock for heat and energy generation. Although some oil palm parts and derivatives like empty fruit bunch and fibre have been commercialized as fuel, less attention has been given to oil palm fronds (OPF). Initial feasibility and characterization studies of OPF showed that it is highly feasible as fuel for gasification to produce high value gaseous fuel or syngas. This paper discusses the experimental gasification attempt carried out on OPF using a 50 kW lab scale downdraft gasifier and its results. The conducted study focused on the temperature distributions within the reactor and the characteristics of the dynamic temperature profile for each temperature zones during operation. OPF feedstock of one cubic inch in individual size with 15% average moisture content was utilized. An average pyrolysis zone temperature of 324°Cand an average oxidation zone temperature of 796°Cwere obtained over a total gasification period of 74 minutes. A maximum oxidation zone temperature of 952°Cwas obtained at 486 lpm inlet air flow rate and 10 kg/hr feedstock consumption rate. Stable bluish flare was produced for more than 70% of the total gasification time. The recorded temperature profiles produced closely similar patterns with the temperature profiles recorded from the gasification of woody materials. Similar temperature profile was obtained comparing the results from OPF gasification with that of woody biomass. Furthermore, the successful ignition of the syngas produced from OPF gasification ascertained that OPF indeed has a higher potential as gasification feedstock. Hence, more detailed studies need to be done for better understanding in exploiting the biomass as a high prospect alternative energy solution. In addition, a study of the effect of initial moisture content of OPF

  8. Experimental study and Monte Carlo modeling of object motion in a bubbling fluidized bed

    OpenAIRE

    García Gutiérrez, Luis Miguel

    2014-01-01

    Mención Internacional en el título de doctor Fluidized beds are employed for a wide variety of applications such as drying, coating of particles, catalytic reactions, or thermal conversion processes. In a number of these applications, objects differing in density and/or size from the dense phase material are found in the bed. These objects can be agglomerates, catalysts or reactants. In this PhD thesis, a fundamental study of the motion of objects is presented, but consideri...

  9. Un estudio experimental de las variables en los problemas elementales de probabilidad

    OpenAIRE

    Ortiz de Haro, Juan J.

    2001-01-01

    En este estudio analizamos los ejercicios y ejemplos de probabilidad presentados en una muestra de libros de texto de bachillerato publicados entre 1975-1991, las variables de tarea de los mismos y comparamos su distribuci??n en dos textos. Nuestra intenci??n es mostrar algunas caracter??sticas generales de los ejercicios y ejemplos presentados en los libros de texto similares a los analizados, que podr??an influir en el significado de la probabilidad presentado al estudiant...

  10. Biomass Pyrolysis in a Fluidized Bed Reactor. Part 2: Experimental Validation of Model Results

    NARCIS (Netherlands)

    Wang, Xiaoquan; Kersten, Sascha R.A.; Prins, Wolter; Swaaij, van Wim P.M.

    2005-01-01

    Various types of cylindrical biomass particles (pine, beech, bamboo, demolition wood) have been pyrolyzed in a batch-wise operated fluid bed laboratory setup. Conversion times, product yields, and product compositions were measured as a function of the particle size (0.7−17 mm), the vapor's residenc

  11. Condiciones térmicas de un dispositivo electrónico en caso de incendio Primera parte: estudio experimental

    Directory of Open Access Journals (Sweden)

    Bruno Chine

    2007-11-01

    Full Text Available En este trabajo se presentan los resultados de un estudio experimental para determinar las condiciones térmicas a la cual un sistema electrónico, usado para radiocomunicaciones en túneles, podría estar sujeto en caso de incendio. El sistema se compone de un dispositivo electrónico contenido en una caja metálica de acero inoxidable 316, un cable coaxial interno y un cable coaxial externo de cobre. Sobre el sistema, que se alberga en una cámara de polímero concreto, ha sido realizada una prueba al fuego con registro experimental de los valores de temperatura en diferentes puntos del sistema mismo. El trabajo experimental ha permitido analizar eficazmente la respuesta del dispositivo electrónico y de los distintos materiales que lo componen a las severas condiciones térmicas de prueba.

  12. Estudio experimental prospectivo sobre el efecto a corto plazo del tratamiento endodóntico en calidad de vida oral

    OpenAIRE

    Lorenzo Moriano, Beatriz

    2013-01-01

    [ES] Realizamos un estudio experimental prospectivo para evaluar la calidad de vida de las personas que se someten a un tratamiento de conductos, valorando el estado doloroso incial, durante y después del tratamiento, sobre una muestra de 250 pacientes,observando como va afectando ese dolor a las distintas dimensiones de la calidad de vida oral [EN] conducted a prospective pilot study to assess the quality of life of people who undergo a root canal treatment, valuing the initial painful st...

  13. Experimental research of the influence of particle size and fluidization velocity on zeolite drying in a two-component fluidized bed

    Directory of Open Access Journals (Sweden)

    Janevski Jelena N.

    2016-01-01

    Full Text Available This paper presents the results of the kinetics research into the drying of fine grained material in a two-component fluidized bed. A review of theoretical and experimental investigations of aerodynamics of the fluidized bed is given, with a special insight into two-component fluidized beds, as well as the basics of heat and material transfer through a fluidized bed. Apart from the theoretical basis of convective drying of wet materials in a stagnant fluidized bed, the paper also emphasizes different approaches to fine grained material drying kinetics. Based on the experimental investigations, where zealots used as a representative of fine grained material and polyethylene as a representative of inert material (another component, an analysis of the influence of working parameters on drying in a two-component fluidized bed is performed. It is established that, apart from the influence of the considered parameters, such as fluidization velocity, diameter of fine grained material particles and drying agent temperature, on the drying curve, the participation of inert material can considerably increase the intensity of heat and material transfer in the fluidized bed. A comparison of the experimental drying curves of fine grained material in the two-component fluidized bed with the results from the studies by other authors shows satisfactory agreement.

  14. Experimental study of the water depth and rainfall intensity effects on the bed roughness coefficient used in distributed urban drainage models

    Science.gov (United States)

    Fraga, Ignacio; Cea, Luis; Puertas, Jerónimo

    2013-11-01

    Variability of roughness coefficients with water depth and rainfall is studied.Experimental measurements and numerical calibration are performed.Results show bed friction variations, not well captured by any standard formulation.

  15. Oxidative coupling of methane in a fixed bed reactor over perovskite catalyst: A simulation study using experimental kinetic model

    Institute of Scientific and Technical Information of China (English)

    Nakisa Yaghobi; Mir Hamid Reza Ghoreishy

    2008-01-01

    The oxidative coupling of methane (OCM) to ethylene over a perovskite titanate catalyst in a fixed bed reactor was studied experimentally and numerically. The two-dimensional steady state model accounted for separate energy equations for the gas and solid phases coupled with an experimental kinetic model. A lumped kinetic model containing four main species CH4, O2, COx (CO2, CO), and C2 (C2H4 and C2H6) was used with a plug flow reactor model as well. The results from the model agreed with the experimental data. The model was used to analyze the influence of temperature and feed gas composition on the conversion and selectivity of the reactor performance. The analytical results indicate that the conversion decreases, whereas, C2 selectivity increases by increasing gas hourly space velocity (GHSV) and the methane conversion also decreases by increasing the methane to oxygen ratio.

  16. Validating Experimental Bedform Dynamics on Cohesive Sand-Mud Beds in the Dee Estuary

    Science.gov (United States)

    Baas, Jaco H.; Baker, Megan; Hope, Julie; Malarkey, Jonathan; Rocha, Renata

    2014-05-01

    Recent laboratory experiments and field measurements have shown that small quantities of cohesive clay, and in particular 'sticky' biological polymers, within a sandy substrate dramatically reduce the development rate of sedimentary bedforms, with major implications for sediment transport rate calculations and process interpretations from the sedimentary record. FURTHER INFORMATION Flow and sediment transport predictions from sedimentary structures found in modern estuaries and within estuarine geological systems are impeded by an almost complete lack of process-based knowledge of the behaviour of natural sediments that consist of mixtures of cohesionless sand and biologically-active cohesive mud. Indeed, existing predictive models are largely based on non-organic cohesionless sands, despite the fact that mud, in pure form or mixed with sand, is the most common sediment on Earth and also the most biologically active interface across a range of Earth-surface environments, including rivers and shallow seas. The multidisciplinary COHBED project uses state-of-the-art laboratory and field technologies to measure the erosional properties of mixed cohesive sediment beds and the formation and stability of sedimentary bedforms on these beds, integrating the key physical and biological processes that govern bed evolution. The development of current ripples on cohesive mixed sediment beds was investigated as a function of physical control on bed cohesion versus biological control on bed cohesion. These investigations included laboratory flume experiments in the Hydrodynamics Laboratory (Bangor University) and field experiments in the Dee estuary (at West Kirby near Liverpool). The flume experiments showed that winnowing of fine-grained cohesive sediment, including biological stabilisers, is an important process affecting the development rate, size and shape of the cohesive bedforms. The ripples developed progressively slower as the kaolin clay fraction in the sandy substrate

  17. Investigation of coalescence kinetics of microcristalline cellulose in fluidised bed spray agglomeration: experimental studies and modelling approach

    Directory of Open Access Journals (Sweden)

    M. Peglow

    2005-06-01

    Full Text Available In this paper a model for fluidized bed spray agglomeration is presented. To describe the processes of heat and mass transfer, a physical based model is derived. The model takes evaporation process from the wetted particles as well as the effects of transfer phenomena between suspension gas and bypass gas into account. The change of particle size distribution during agglomeration, modeled by population balances, is linked to the heat and mass transfer model. A new technique is derived to extract agglomeration and nucleation rates from experimental data. Comparisons of experiments and simulations are presented.

  18. Numerical simulation of fluid bed drying based on two-fluid model and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Assari, M.R. [Jundi-shapur University, Dezful (Iran); Basirat Tabrizi, H.; Saffar-Avval, M. [Amirkabir University of Technology, Department of Mechanical Engineering, Tehran (Iran)

    2007-02-15

    A mathematical model for batch drying based on the Eulerian 'two-fluid models' was developed. The two-dimensional, axis-symmetrical cylindrical equations for both phases were solved numerically. The governing equations were discretized using a finite volume method with local grid refinement near the wall and inlet port. The effects of parameters such as inlet gas velocity and inlet gas temperature on the moisture content, temperature of solid and gas at the outlet are shown. This data from the model was compared with that obtained from experiments with a fluidized bed and found to be in reasonably good agreement. (author)

  19. Experimental study on bed-load sediment transport under irregular wave and current combined flow

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Using an irregularly oscillating tray and flume, a series of experiments are completed to evaluate bed-load sediment transport rate under irregular wave- current coexistent fild. Testing conditions include three interaction angles 0°, 45°, 90° and two kinds of median sizes (0.38 and 1.10 mm).The results of transport rate show that the net sediment transport rate can be expressed approximately as the function of the maximum bottom shear stress of waves, mean shear stress of current and the grain size.

  20. Experimental analysis of minimum shear stress to drag particles in a horizontal bed; Analise experimental da tensao de cisalhamento minima para arraste de particulas em um leito horizontal

    Energy Technology Data Exchange (ETDEWEB)

    Dornelas, Breno Almeida; Soares, Edson Jose [Universidade Federal do Espirito Santo. Departamento de Engenharia Mecanica (Brazil)], e-mails: bad@ucl.br, edson@ct.ufes.br; Quirino Filho, Joao Pedro; Loureiro, Bruno Venturini [Faculdade do Centro Leste (UCL). Laboratorio de Fluidos e Fenomenos de Transporte (Brazil)], e-mails: joaoquirino@ucl.br, brunovl@ucl.br

    2009-12-15

    Efficient hole cleaning is still a challenge in well bore drilling to produce oil and gas. The critical point is the horizontal drilling that inherently tends to form a bed of sediment particles at the well bottom during drilling. The cuttings bed erosion depends mainly on the shear stress promoted by the drilling fluid flow. The shear stress required to cause drag in the cuttings bed is investigated according to the fluid and particles properties, using an experimental assembly, composed of: a system for fluid circulation, a particle box, a pump system and measuring equipment. The observation area is a box below the flow line in an acrylic duct used to calibrate sand particles. The test starts with the pumps in a low frequency which is increased in steps. At each frequency level, images are captured of carried particles and the established flow rate is recorded. The images are analyzed when the dragged particle is no longer random and sporadic, but becomes permanent. The shear stress is identified by the PKN correlation (by Prandtl, von Karman, and Nikuradse) for the minimum flow rate necessary to cause drag. Results were obtained for just water and water-glycerin solution flows. (author)

  1. Experimental studies on the coolability of packed beds. Flooding of hot dry packed beds; Experimentelle Untersuchungen zur Kuehlbarkeit von Schuettbetten. Fluten heisser, trockener Schuettungen

    Energy Technology Data Exchange (ETDEWEB)

    Leininger, S.; Kulenovic, R.; Laurien, E. [Stuttgart Univ. (Germany). Inst. fuer Kernenergetik und Energiesysteme (IKE)

    2013-07-01

    In case of a severe accident in a nuclear power plant meltdown of the reactor core can occur and form a packed bed in the lower plenum of the reactor pressure vessel (RPV) after solidification due to contact with water. The removal of after-heat and the long-term coolability is of essential interest. The efficient injection of cooling water into the packed bed has to be assured without endangering the structural integrity of the reactor pressure vessel. The experiments performed aimed to study the dry-out and the quenching (flooding) of hot dry packed beds. Two different inflow variants, bottom- and top-flooding including the variation of the starting temperature of the packed bed and the injection rate were studied. In case of bottom flooding the quenching time increases with increasing packed bed temperature and decreasing injection rate. In case of top flooding the flow pattern is more complex, in a first phase the water flows preferentially toward the RPV wall, the flow paths conduct the water downwards. The flow resistance of the packed bed increases with increasing bed temperatures. The quenching temperatures increase significantly above average.

  2. Modeling and Experimental Studies of Mercury Oxidation and Adsorption in a Fixed-Bed and Entrained-Flow Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Buitrago, Paula A. [Univ. of Utah, Salt Lake City, UT (United States); Morrill, Mike [Univ. of Utah, Salt Lake City, UT (United States); Lighty, JoAnn S. [Univ. of Utah, Salt Lake City, UT (United States); Silcox, Geoffrey D. [Univ. of Utah, Salt Lake City, UT (United States)

    2009-06-01

    This report presents experimental and modeling mercury oxidation and adsorption data. Fixed-bed and single-particle models of mercury adsorption were developed. The experimental data were obtained with two reactors: a 300-W, methane-fired, tubular, quartz-lined reactor for studying homogeneous oxidation reactions and a fixed-bed reactor, also of quartz, for studying heterogeneous reactions. The latter was attached to the exit of the former to provide realistic combustion gases. The fixed-bed reactor contained one gram of coconut-shell carbon and remained at a temperature of 150°C. All methane, air, SO2, and halogen species were introduced through the burner to produce a radical pool representative of real combustion systems. A Tekran 2537A Analyzer coupled with a wet conditioning system provided speciated mercury concentrations. At 150°C and in the absence of HCl or HBr, the mercury uptake was about 20%. The addition of 50 ppm HCl caused complete capture of all elemental and oxidized mercury species. In the absence of halogens, SO2 increased the mercury adsorption efficiency to up to 30 percent. The extent of adsorption decreased with increasing SO2 concentration when halogens were present. Increasing the HCl concentration to 100 ppm lessened the effect of SO2. The fixed-bed model incorporates Langmuir adsorption kinetics and was developed to predict adsorption of elemental mercury and the effect of multiple flue gas components. This model neglects intraparticle diffusional resistances and is only applicable to pulverized carbon sorbents. It roughly describes experimental data from the literature. The current version includes the ability to account for competitive adsorption between mercury, SO2, and NO2. The single particle model simulates in-flight sorbent capture of elemental mercury. This model was developed to include Langmuir and Freundlich isotherms, rate equations, sorbent feed rate, and

  3. Experimental study of vertical stress profiles of a confined granular bed under static and dynamic conditions.

    Science.gov (United States)

    Mandato, S; Cuq, B; Ruiz, T

    2012-07-01

    In a wet agglomeration process inside a low shear mixer, the blade function is to induce i) homogenization of the liquid sprayed on the powder surface and ii) a stress field able to transfer the mechanical energy at the particle scale. In this work we study the mechanical state of a confined powder bed through the analysis of stress distributions (by force measurements) in a rectangular cell in two cases: for a classical model powder (i.e. glass beads) and a complex powder (i.e. wheat semolina). Two types of vertical stress profiles are obtained according to the type of measurements carried out in the powder bed, either locally (at different positions in the cell) or globally (at the entire base). The global vertical stress profile follows Janssen's model and the local vertical stress profile highlights a critical length, identified as the percolation threshold of the force network, and a shielding length near the bottom, which is similar to an influence length of the side walls. In the context of wet agglomeration, the results allow to consider the role of the characteristic lengths in the mixing bowl under vertical mechanical solicitation.

  4. Experimental Study and Computational Simulations of Key Pebble Bed Thermo-mechanics Issues for Design and Safety

    Energy Technology Data Exchange (ETDEWEB)

    Tokuhiro, Akira; Potirniche, Gabriel; Cogliati, Joshua; Ougouag, Abderrafi

    2014-07-08

    An experimental and computational study, consisting of modeling and simulation (M&S), of key thermal-mechanical issues affecting the design and safety of pebble-bed (PB) reactors was conducted. The objective was to broaden understanding and experimentally validate thermal-mechanic phenomena of nuclear grade graphite, specifically, spheres in frictional contact as anticipated in the bed under reactor relevant pressures and temperatures. The contact generates graphite dust particulates that can subsequently be transported into the flowing gaseous coolent. Under postulated depressurization transients and with the potential for leaked fission products to be adsorbed onto graphite 'dust', there is the potential for fission products to escape from the primary volume. This is a design safety concern. Furthermore, earlier safety assessment identified the distinct possibility for the dispersed dust to combust in contact with air if sufficient conditions are met. Both of these phenomena were noted as important to design review and containing uncertainty to warrant study. The team designed and conducted two separate effects tests to study and benchmark the potential dust-generation rate, as well as study the conditions under which a dust explosion may occure in a standardized, instrumented explosion chamber.

  5. Experimental and mechanism studies on simultaneous desulfurization and denitrification from flue gas using a flue gas circulating fluidized bed

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yi; XU PeiYao; SUN XiaoJun; WANG LiDong

    2007-01-01

    The oxidizing highly reactive absorbent was prepared from fly ash, industry lime, and an oxidizing additive M. Experiments of simultaneous desulfurization and denitrification were carried out in a flue gas circulating fluidized bed (CFB). The effects of influencing factors and calcium availability were also investigated on the removal efficiencies of desulfurization and denitrification. Removal efficiencies of 95.5% for SO2 and 64.8% for NO were obtained respectively under the optimal experimental conditions. The component of the spent absorbent was analyzed with chemical analysis methods. The results indicated that more nitrogen species appeared in the spent absorbent except sulfur species. A scanning electron microscope (SEM) and an accessory X-ray energy spectrometer were used to observe micro-properties of the samples, including fly ash, oxidizing highly reactive absorbent and spent absorbent. The simultaneous removal mechanism of SO2 and NO based on this absorbent was proposed according to the experimental results.

  6. 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.

  7. Numerical and experimental studies on effects of moisture content on combustion characteristics of simulated municipal solid wastes in a fixed bed

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Rui, E-mail: Sunsr@hit.edu.cn [School of Energy Science and Engineering, Harbin Institute of Technology, 92, West Dazhi Street, Harbin 150001 (China); Ismail, Tamer M., E-mail: temoil@aucegypt.edu [Department of Mechanical Engineering, Suez Canal University, Ismailia (Egypt); Ren, Xiaohan [School of Energy Science and Engineering, Harbin Institute of Technology, 92, West Dazhi Street, Harbin 150001 (China); Abd El-Salam, M. [Department of Basic Science, Cairo University, Giza (Egypt)

    2015-05-15

    Highlights: • The effects of moisture content on the burning process of MSW are investigated. • A two-dimensional mathematical model was built to simulate the combustion process. • Temperature distributions, process rates, gas species were measured and simulated. • The The conversion ratio of C/CO and N/NO in MSW are inverse to moisture content. - Abstract: In order to reveal the features of the combustion process in the porous bed of a waste incinerator, a two-dimensional unsteady state model and experimental study were employed to investigate the combustion process in a fixed bed of municipal solid waste (MSW) on the combustion process in a fixed bed reactor. Conservation equations of the waste bed were implemented to describe the incineration process. The gas phase turbulence was modeled using the k–ε turbulent model and the particle phase was modeled using the kinetic theory of granular flow. The rate of moisture evaporation, devolatilization rate, and char burnout was calculated according to the waste property characters. The simulation results were then compared with experimental data for different moisture content of MSW, which shows that the incineration process of waste in the fixed bed is reasonably simulated. The simulation results of solid temperature, gas species and process rate in the bed are accordant with experimental data. Due to the high moisture content of fuel, moisture evaporation consumes a vast amount of heat, and the evaporation takes up most of the combustion time (about 2/3 of the whole combustion process). The whole bed combustion process reduces greatly as MSW moisture content increases. The experimental and simulation results provide direction for design and optimization of the fixed bed of MSW.

  8. Experimental and Numerical Study on Ultra-Low Concentration Coal Bed Methane Combustion in a Fluidized Bed%超低浓度煤层气在流化床中燃烧的实验和数值研究

    Institute of Scientific and Technical Information of China (English)

    杨仲卿; 张力; 唐强; 蒲舸

    2011-01-01

    超低浓度煤层气由于甲烷含量低、浓度变化大而较难加以利用。采用实验和数值模拟的方法,研究了超低浓度煤层气在流化床中的燃烧,分析了床层温度、甲烷体积浓度,流化风速对甲烷燃烧效率的影响,并用数学模型预测了甲烷沿床层高度方向的分布。研究表明,数学模型和实验数据吻合较好。床层温度是煤层气燃烧反应的关键因素,甲烷的转化率随着床层温度的升高而增加。燃烧反应主要发生在乳化相,且主要集中在床层的下部。甲烷的转化率随着流化风速和煤层气中甲烷浓度的增加而减少。在床层温度为650℃时,甲烷浓度低于1%的煤层气的甲烷转化率均大于93%。增加床层高度可使甲烷完全转化。%The ultra-low concentration coal bed methane is difficult to utilize due to its low methane content and fluctuated concentration. Coal bed methane combustion in a fluidized bed was studied experimentally and numerically. The effects of bed temperature, methane volumetric concentration and fluidized velocity on methane conversion were analyzed. The methane profile along bed height was predicted with the mathematical model. The results show that the model compares reasonably well with experimental data. Bed temperature is a major factor on combustion. And the methane conversion increases with the rising bed temperature. The combustion reaction is mainly occurred in the emulsion phase and at lower part of the bed. The methane conversion decreases with the increasing fluidized velocity and inlet methane concentration. When the bed temperature is 650℃ and methane concentration is less than 1%, the conversion is greater than 93%. More methane can be consumed when the bed height is increasing.

  9. Experimental purification of paclitaxel from a complex mixture of taxanes using a simulated moving bed

    Directory of Open Access Journals (Sweden)

    M. A. Cremasco

    2009-03-01

    Full Text Available A laboratory-scale simulated moving bed (SMB was designed and tested for the separation of paclitaxel, a powerful anti-cancer agent known as Taxol@, from impurities of a plant tissue culture (PTC broth. The innovative strategy of a pseudo-binary model, where mixtures A and B were treated as single solutes A and B, was used in the linear standing wave analysis to fix the SMB operating parameters for a multicomponent and complex system. Linear standing wave design was used to specify the zone flow rates and the switching time for the laboratory-scale SMB unit, with two steps of separation. The SMB consists of four packed columns, where each column is 12.5 cm in length and 1.5 cm in diameter. Two sequential separation steps were used to recover paclitaxel from a small feed batch (less than one liter. Placlitaxel was recovered from the complex plant tissue culture broth in 82% yield and 72% purity.

  10. An Experimental and Computational Study of Multiphase Flow Behaviour in Circulating Fluidized Beds

    Energy Technology Data Exchange (ETDEWEB)

    Mathiesen, Vidar

    1997-12-31

    Gas/solid flows have been studied extensively, mainly because they are important in nuclear, chemical and petroleum industries. This thesis describes an experiment done at two different circulating fluidized bed systems. Laser Doppler anemometry (LDA) and phase Doppler anemometry (PDA) were used to measure mean and fluctuating velocity, diameter and solids concentration. A typical core-annulus flow was obtained in both cases. The measurements show a relative mean velocity as well as a relative fluctuating velocity between different particle sizes. An axial segregation by size and its variation with the superficial gas velocity are demonstrated. Significant radial segregation is found in both risers. A three-dimensional Computational Fluid Dynamics model was developed based on Eulerian description of the phases where the kinetic theory of granular flow is the basis of the turbulence modelling in the solid phases. There are one gas phase and any number of solid phases. Simulations of flow behaviour in two- and three-dimensions agree well with experiments and the model is able to handle axial segregation by size for different superficial gas velocities and particle size distributions. 107 refs., 79 figs., 6 tabs.

  11. 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.

  12. EXPERIMENTAL RESEARCH OF FLOW STRUCTURE IN A GAS-SOLID CIRCULATING FLUIDIZED BED RISER BY PIV

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Particle Imaging Velocimetry (PIV) techniques were applied to investigate the particle motion and cluster properties in a gas-solid two-phase flow in a circulating fluidized bed riser. Visual images and micro-structure of various clusters were captured. After the boundary of clusters was determined by the gray level threshold method, clusters were classified by the distance between particles and the shape and position of clusters. In addition, the process of clusters forming and breaking up was described, and the sizes of clusters were also obtained. With the Minimum Quadric Difference (MQD) cross-correlation algorithm suitable for high-density particles, the axial velocities of the particles were obtained in the dilute phase section. The features of particle motion were revealed by investigating statistically the magnitude and distribution of particle axial velocity in the radial direction. At most radial cross-sections, there exists a parabola-shaped distribution of upward axial velocity of particles, namely, the magnitude of axial velocity in the core region is higher than that near the wall region of the riser.

  13. Estudio experimental del decaimiento radiactivo por medio de analogías clásicas.

    OpenAIRE

    Pinilla, E. C.; Ramírez, O. L.; Fajardo, F.

    2014-01-01

    En este trabajo se describe un montaje experimental de bajo costo de implemetación en cualquier laboratorio de física moderna, con el fin de ilustrar el decaimiento nuclear por medio de un modelo clásico. Se realizan montajes para simular, i) el decaimiento de un sistema de núcleos del mismo tipo, ii) el decaimiento de dos sistemas de núcleos diferentes poblando a otros sistema y iii) el análogo a series de decaimiento nucleares de tres y cuatro sistemas. Los montajes se construyeron utilizan...

  14. El cuello femoral en la enfermedad de Perthes. Estudio experimental en conejos

    OpenAIRE

    Carranza Bencano, A.

    1999-01-01

    Introducción: Aunque el substrato básico y fundamental de la enfermedad de Perthes es la osteocondritis por isquemia del núcleo de osificación de la extremidad proximal del fémur, no se ha conseguido la reproducción experimental de la misma. Objetivo: Reproducir experimentalmente,en el conejo, la isquemia del núcleo epifisario y comprobar si las lesiones obtenidas son superponibles a las conocidas de esta enfermedad en el hombre. Observar la evolución de estas lesiones y poder ...

  15. Aloinjertos y autoinjertos de ligamento cruzado anterior de la rodilla: estudio experimental en el perro

    OpenAIRE

    Minguet Baixauli, J. E.; Gomar Sancho, Francisco; Saenz López de Rueda, F.

    1994-01-01

    Hemos realizado un trabajo de cirugía experimental en perros, en el que comparamos el comportamiento de los autoinjertos frescos de ligamento cruzado anterior de la rodilla (LCA), con lo aloinjertos crioconservados. Con la ayuda de una guía y trefinas, se extrae el LCA con sus inserciones, unido a un taco óseo en cada extremo. Los autoinjertos se reimplantan tras unos minutos en suero fisiológico. Los aloinjertos son sometidos a congelación y, almacenamiento a —80 °C y desconge...

  16. Experimental study of a bubbling fluidized bed with a rotating distributor

    OpenAIRE

    Sobrino Fernández, Celia

    2008-01-01

    Esta tesis consiste en la caracterización experimental de la hidrodinámica de un nuevo lecho fluido de distribuidor rotatorio. Existen numerosas referencias en la literatura en las que se analizan los factores que influyen en la calidad de la fluidización en lechos burbujeantes, como son la tasa de mezcla, el tamaño de burbuja y la heterogeneidad en el lecho. Entre estos factores se encuentran la geometría del lecho, el caudal de gas empleado en la fluidización y el tipo de dis...

  17. Experimental Study of Integrated Ebullated-bed and Fixed-bed for Hydrotreating Mid-Low Temperature Coal Tar to Clean Fuel

    Institute of Scientific and Technical Information of China (English)

    Meng Zhaohui; Yang Tao; Fang Xiangchen

    2016-01-01

    A new hydrotreating technology integrating the ebullated-bed (EB) and the fixed-bed (FB) hydrogenation was proposed to investigate the efficiency for hydrotreating mid- low-temperature coal tar to clean fuel, and multiple tests at the bench scale were carried out. The results showed that the distillates obtained from EB reactors were greatly upgraded and could meet the requirements of FB unit without discarding any tail oil. The naphtha produced from FB reactors could be fed to the catalytic reforming unit, while a high quality diesel was also obtained. The unconverted oil (UCO) could be fur-ther hydrocracked to clean fuel. It is found that the removal of impurities from the coal tar oil is related with the molecular aggregation structure and composition of the coal tar. Application of the integrated hydrotreating technology to the high-temperature coal tar processing demonstrated that more than half of heavy components could be effectively upgraded.

  18. Experimental and mechanism studies on simultaneous desulfurization and denitrification from flue gas using a flue gas circulating fluidized bed

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The oxidizing highly reactive absorbent was prepared from fly ash,industry lime,and an oxidizing additive M.Experiments of simultaneous desulfurization and denitrification were carried out in a flue gas circulating fluidized bed(CFB).The effects of influencing factors and calcium availability were also investigated on the removal efficiencies of desulfurization and denitrification.Removal efficiencies of 95.5%for SO2 and 64.8%for NO were obtained respectively under the optimal experimental conditions. The component of the spent absorbent was analyzed with chemical analysis methods.The results in- dicated that more nitrogen species appeared in the spent absorbent except sulfur species.A scanning electron microscope(SEM)and an accessory X-ray energy spectrometer were used to observe micro-properties of the samples,including fly ash,oxidizing highly reactive absorbent and spent absorbent.The simultaneous removal mechanism of SO2 and NO based on this absorbent was pro- posed according to the experimental results.

  19. Real-Time Signal Processing for Multiantenna Systems: Algorithms, Optimization, and Implementation on an Experimental Test-Bed

    Directory of Open Access Journals (Sweden)

    Haustein Thomas

    2006-01-01

    Full Text Available A recently realized concept of a reconfigurable hardware test-bed suitable for real-time mobile communication with multiple antennas is presented in this paper. We discuss the reasons and prerequisites for real-time capable MIMO transmission systems which may allow channel adaptive transmission to increase link stability and data throughput. We describe a concept of an efficient implementation of MIMO signal processing using FPGAs and DSPs. We focus on some basic linear and nonlinear MIMO detection and precoding algorithms and their optimization for a DSP target, and a few principal steps for computational performance enhancement are outlined. An experimental verification of several real-time MIMO transmission schemes at high data rates in a typical office scenario is presented and results on the achieved BER and throughput performance are given. The different transmission schemes used either channel state information at both sides of the link or at one side only (transmitter or receiver. Spectral efficiencies of more than 20 bits/s/Hz and a throughput of more than 150 Mbps were shown with a single-carrier transmission. The experimental results clearly show the feasibility of real-time high data rate MIMO techniques with state-of-the-art hardware and that more sophisticated baseband signal processing will be an essential part of future communication systems. A discussion on implementation challenges towards future wireless communication systems supporting higher data rates (1 Gbps and beyond or high mobility concludes the paper.

  20. Experimental investigation of wood combustion in a fixed bed with hot air

    Energy Technology Data Exchange (ETDEWEB)

    Markovic, Miladin, E-mail: m.markovic@utwente.nl; Bramer, Eddy A.; Brem, Gerrit

    2014-01-15

    Highlights: • Upward combustion is a new combustion concept with ignition by hot primary air. • Upward combustion has three stages: short drying, rapid devolatilization and char combustion. • Variation of fuel moisture and inert content have little influence on the combustion. • Experimental comparison between conventional and upward combustion is presented. - Abstract: Waste combustion on a grate with energy recovery is an important pillar of municipal solid waste (MSW) management in the Netherlands. In MSW incinerators fresh waste stacked on a grate enters the combustion chamber, heats up by radiation from the flame above the layer and ignition occurs. Typically, the reaction zone starts at the top of the waste layer and propagates downwards, producing heat for drying and devolatilization of the fresh waste below it until the ignition front reaches the grate. The control of this process is mainly based on empiricism. MSW is a highly inhomogeneous fuel with continuous fluctuating moisture content, heating value and chemical composition. The resulting process fluctuations may cause process control difficulties, fouling and corrosion issues, extra maintenance, and unplanned stops. In the new concept the fuel layer is ignited by means of preheated air (T > 220 °C) from below without any external ignition source. As a result a combustion front will be formed close to the grate and will propagate upwards. That is why this approach is denoted by upward combustion. Experimental research has been carried out in a batch reactor with height of 4.55 m, an inner diameter of 200 mm and a fuel layer height up to 1 m. Due to a high quality two-layer insulation adiabatic conditions can be assumed. The primary air can be preheated up to 350 °C, and the secondary air is distributed via nozzles above the waste layer. During the experiments, temperatures along the height of the reactor, gas composition and total weight decrease are continuously monitored. The influence of

  1. Experimental study of near-wall turbulent characteristics in an open-channel with gravel bed using an acoustic Doppler velocimeter

    Science.gov (United States)

    Wang, X. Y.; Yang, Q. Y.; Lu, W. Z.; Wang, X. K.

    2012-01-01

    This experimental study investigated the mean velocity profiles, skin friction and turbulent characteristics of a gravel bed over a wide range of roughness using an acoustic Doppler velocimeter (ADV). The median diameter of bed material ranged from 2 to 40 mm, and the normalized roughness heights ranged from 47 to 4,881 mm. The flow regime was fully developed turbulence with a Reynolds number in the range of 4.2 × 104-9.86 × 104. All velocity curves exhibited logarithmic distributions, and the log-law region was influenced greatly by both the roughness and the Reynolds number. Moreover, the roughness of the gravel bed exerted a strong effect on Reynolds stress, and the turbulence tended towards isotropic with increasing roughness. Using statistical analyses, the third-order turbulence moments, sweep, and ejection motions were also examined. The results of this experimental analysis present a contrast to the classical wall similarity hypothesis.

  2. Complex plasma experimental device – A test bed for studying dust vortices and other collective phenomena

    Indian Academy of Sciences (India)

    MANJIT KAUR; SAYAK BOSE; P K CHATTOPADHYAY; J GHOSH; Y C SAXENA

    2016-12-01

    A typical device for carrying out sophisticated and complex dusty plasma experiments is designed, fabricated and made operational at the Institute for Plasma Research, India. The device is named as complex plasma experimental device (CPED). The main aim of this multipurpose machine is to study the formation and behaviour of dust vortices in the absence of external magnetic field under the effect of various plasma parameters. Further, the device is equipped with advanced imaging diagnostics for studying many other interesting phenomena such as dust oscillations, three-dimensional crystalline structures, dust rotation, etc. The device is quite flexible to accommodate many innovative experiments. Detailed design of the device, its diagnostics capabilities and theadvanced image analysis techniques are presented in this paper.

  3. EXPERIMENTAL AND THEORETICAL STUDY OF ADIABATIC HUMIDIFICATION IN HVAC&R APPLICATIONS ESTUDIO TEÓRICO EXPERIMENTAL DE LA HUMIDIFICACION ADIABÁTICA EN APLICACIONES HVAC&R

    Directory of Open Access Journals (Sweden)

    Néstor Fonseca

    2010-08-01

    Full Text Available This article presents the results of the study performed to obtain a theoretical unified treatment of adiabatic humidification to be applied in refrigeration and air conditioning systems that can be used as a calculate tool in field as a part of diagnosis in audit processes of this kind of systems. To achieve this, a series of tests and experimental analysis are performed on two types of systems. The computational model is able to predict the effectiveness of the system and the main variables at the system exhaust as temperature and humidity by using the measurement of temperature and mass flow rates that participle in the energy and mass and transfer. The key in the analysis is the global heat transfer coefficient AU, considering the influence of the water an air mass flow rates in the system. An example of each system considered in this study is shown, illustrating the validation of the model.Este artículo presenta los resultados del estudio realizado para obtener un tratamiento teórico unificado de la humidificación adiabática, aplicable a sistemas de refrigeración y acondicionamiento de aire con la cual generar una herramienta de cálculo que pueda ser utilizada en terreno como parte de su diagnóstico en auditorías energéticas de este tipo de sistemas. Para lograr esto se realizan una serie de ensayos y análisis de tipo experimental en dos diferentes clases de equipo. El modelo computacional permite predecir la efectividad del sistema y principales variables de salida como la temperatura y contenido de humedad mediante la medición de las condiciones de entrada de temperatura y flujos másicos de los fluidos que intervienen en la transferencia de masa y energía. La clave en el análisis es la definición del coeficiente global de transferencia de calor AU, considerando la influencia de los flujos de agua y aire en el sistema. Se describe un ejemplo de validación del modelo por cada tipo de sistema seleccionado en este estudio.

  4. The grinding of uranium dioxide from fluidized beds; Estudio del m icronizado del UO{sub 2} procedente de lechos Fluidizados

    Energy Technology Data Exchange (ETDEWEB)

    Alonso Folgueras, J. A.

    1974-07-01

    This work deals with the UO{sub 2} vibratory grinding, the UO{sub 2} obtained from fluidized beds. In this study the grinding time has been correlated with surface area, stoichiometry, granulometry and grinded product contamination. The efficiency losses in the grinding of moisten UO{sub 2} are outlined. Finally it is made a brief study of the granulate obtained from the grinded UO{sub 2} as well as the green pellets resulting from it, taking into consideration the dispersion of its density and height. (Author)

  5. Equivalent materials simulation experimental study on bed separations developing and mining subsidence in constant humidity and constant temperature conditions

    Institute of Scientific and Technical Information of China (English)

    FU Zhi-liang; WANG Su-hua; GAO Yan-fa

    2008-01-01

    A new experiment was made on the developing of bed separations and mining subsidence from Tangshan T2192 working face by equivalent materials simulation.The overburden deformation and the developing of bed separations with working face advancing was simulated by a new model.The results show that the maximum value of bed separations moved forward gradually along with the working face advancing; the maximum value of bed separations is 0.31~0.50 times of mining thickness.The key strata have a great influence upon surface subsidence during the overburden movement process.The mechanics parameters of new experiment are fitted with results in fields perfectly.

  6. Equivalent materials simulation experimental study on bed separations developing and mining subsidence in constant humidity and constant temperature conditions

    Institute of Scientific and Technical Information of China (English)

    FU Zhi-liang; WANG Su-hua; GAO Yan-fa

    2008-01-01

    A new experiment was made on the developing of bed separations and mining subsidence from Tangshan T2192 working face by equivalent materials simulation. The overburden deformation and the developing of bed separations with working face advanc-ing was simulated by a new model. The results show that the maximum value of bed separations moved forward gradually along with the working face advancing; the maxi-mum value of bed separations is 0.31 ~0.50 times of mining thickness. The key strata have a great influence upon surface subsidence during the overburden movement process. The mechanics parameters of new experiment are fitted with results in fields perfectly.

  7. Incorporación de aloinjertos óseos intercalares corticales: Estudio experimental en conejos Incorporation of cortical intercalary bone allografts: Experimental study on rabbits

    Directory of Open Access Journals (Sweden)

    S. Amillo

    2003-12-01

    Full Text Available Se realiza un estudio experimental en 40 conejos para valorar la incorporación de grandes aloinjertos óseos intercalares y la influencia de la congelación en el injerto óseo. En 36 conejos adultos se procedió a resecar 3 centímetros diafisarios de tibia y el defecto se reconstruyó con diferente tipo de injerto óseo: autoinjerto fresco y autoinjerto congelado, aloinjerto fresco y aloinjerto congelado; la osteosíntesis se realizó con dos agujas de Kirschner intramedulares. Se hicieron estudios radiológicos mensuales hasta el sacrificio, a los 2, 4 y 8 meses. Se hizo un estudio densitométrico, histológico y de diafanización con técnica de Spalteholz de las tibias. En 24 animales se administraron 25 mg/kg de oxytetraciclina al 3º y 6º días antes del sacrificio para estudiar la velocidad de aposición ósea en el injerto. Observamos una consolidación radiológica buena y excelente en el 80% de los injertos (99% en los autoinjertos y 66% en los aloinjertos. La densidad ósea mostraba un descenso hasta el 4º mes debido a la reabsorción ósea excepto en el grupo de los aloinjertos frescos. La revascularización de los aloinjertos fue más lenta y pobre que en los autoinjertos, pero con el mismo patrón vascular. La incorporación y neoformación ósea fueron mayores en los autoinjertos sin diferencias significativas con los aloinjertos congelados. La velocidad de aposición ósea no se modificó con los diferentes tipos de injertos óseos utilizados. La congelación facilita y acelera la incorporación y cantidad de neoformación ósea de los aloinjertos.An experimental study was carried out on 40 rabbits in order to evaluate the incorporation of large intercalary bone allografts and the influence of freezing on the bone graft. In 36 rabbits resection of 3 centimetres of diaphysis of the tibia was carried out and the defect was rebuilt with different types of bone graft: fresh autograft and frozen autograft, fresh allograft and

  8. Effects of experimental passive artificial recharge of treated surface water on water quality in the Equus Beds Aquifer, 2009-2010

    Science.gov (United States)

    Garinger, Linda Pickett; King, Aaron S.; Ziegler, Andrew C.

    2011-01-01

    Declining water levels and concerns about the migration of a known saltwater plume upgradient from public supply wells prompted the City of Wichita to investigate the feasibility of using artificial recharge to replenish the water supply in the Equus Beds aquifer. After preliminary testing, the City of Wichita began Phase I of the Equus Beds Aquifer Storage and Recovery Project in 2006. In 2009, the City of Wichita installed an experimental passive gravity recharge well and trench system to increase artificial recharge at Recharge Basin 1, one of the six Phase ? recharge sites.

  9. CLC in packed beds using syngas and CuO/Al2O3: model description and experimental validation

    NARCIS (Netherlands)

    Hamers, H.P.; Gallucci, F.; Cobden, P.D.; Kimball, E.; Sint Annaland, M. van

    2014-01-01

    The objective of this work is to study the performance of the oxygen carrier in a packed bed with periodic switching between oxidizing and reducing conditions. In this paper the performance of CuO/Al2O3 as the oxygen carrier in a packed bed reactor with syngas as the fuel are investigated, while als

  10. Theoretical and Experimental Substantiation for Applicability of a Damping Layer in a Foundation Slab Placed on Soil Bed

    Directory of Open Access Journals (Sweden)

    Kiselev Nikita

    2016-01-01

    Full Text Available Authors present the results of studies of innovative foundation structure. The idea of how to increase the operational quality of foundations and reduce the costs due to rational loading of the soil bed is numerically simulated. It is shown that the bending moment in the foundation slab depends on uneven settlements of the soil bed. It is proposed to stabilize the deformable soil bed by the damping layer placed under the slab footing in the zones with minor settlements. Considered is the concept of the damping layer in the foundation slab placed on the soil bed (DLS. The in-situ test for DLS-clayey bed interaction is described. Given are the results obtained after the experiments for DLS performance. The result of DLS implementation in designing the foundation of the 22-storeyed block of flats is considered. The expediency of DLS in comparison to standard foundations is presented.

  11. Theoretical and experimental drying of a cylindrical sample by applying hot air and infrared radiation in an inert medium fluidized bed

    Directory of Open Access Journals (Sweden)

    B. Honarvar

    2012-06-01

    Full Text Available Drying of a cylindrical sample in a fluidized bed dryer containing inert particles was studied. For this purpose, a pilot-scaled fluidized bed dryer was constructed in which two different heat sources, hot air and infrared radiation were applied, and pieces of carrot were chosen as test samples. The heat transfer coefficient for cylindrical objects in a fluidized bed was also measured. The heat absorption coefficient for carrot was studied. The absorption coefficient can be computed by dividing the absorbed heat by the carrot to the heat absorbed for the water and black ink. In this regard, absorbed heat values by the carrot, water and black ink were used A mathematical model was proposed based on the mass and heat transfer phenomena within the drying sample. The results obtained by the proposed model were in favorable agreement with the experimental data.

  12. Experimental numerical study utilizing CFD in a stratified gasifier operating with biomass; Estudio numerico experimental de un gasificador estratificado que opera con biomasa, utilizando CFD

    Energy Technology Data Exchange (ETDEWEB)

    Rogel Ramirez, Alejandro

    2007-07-01

    The central idea behind this work is the developing of a numeric-experimental model, useful to optimize the biomass stratified gasifier design. Firstly, model validation will be carried up by comparison with reference experimental data available. This study describes a 1-D + 2-D numerical model used to simulate the gasification of pine wood pellets in a stratified downdraft gasifier whereby Eulerian conservation equations are solved for particle and gas phase components, velocities and specific enthalpies. The model takes into account the biomass particle process such as heating up, drying, primary pyrolysis of biomass, secondary pyrolysis of tar, homogeneous reactions and heterogeneous combustion/gasification reactions, and particle size change. This CFD model can be used to predict temperature profiles, gas composition, producer gas lower heating value, and carbon conversion efficiency, and the reactor performance when operating parameters and feed properties are changed. The standard {kappa}-{epsilon} and RNG {kappa}-{epsilon} models were used to simulate the turbulent flow conditions. [Spanish] La idea central del presente trabajo es el desarrollo de un modelo numerico- experimental, para optimizar el diseno de gasificadores estratificados de biomasa. Primeramente, el modelo sera validado utilizando datos experimentales disponibles en la literatura. Este estudio describe un modelo numerico 1-D+2-D, utilizado para simular la gasificacion de 'pelets' de madera de pino en un gasificador estratificado de flujos paralelos, en el que se resuelven ecuaciones de conservacion Eulerianas para los componentes de la fase gaseosa, la fase solida, velocidades y entalpias especificas. El modelo considera procesos como: calentamiento, secado de la biomasa, pirolisis primaria de la madera, pirolisis secundaria de los alquitranes, reacciones homogeneas, reacciones heterogeneas de combustion/gasificacion y cambio en el tamano de la particula. Este modelo CFD puede ser

  13. 黏性泥石流沟床冲刷深度试验研究%Experimental study on gully bed erosion depth of viscous debris flow

    Institute of Scientific and Technical Information of China (English)

    赵彦波; 游勇; 柳金峰; 林雪平

    2012-01-01

      黏性泥石流冲刷沟床,会导致建筑物构筑物基础失稳,从而毁坏工程设施。本文通过室内水槽试验探究黏性泥石流沟床冲刷深度规律。试验结果表明:黏性泥石流沟床冲刷深度主要受沟床坡度、泥石流容重以及沟床物质容重的影响;黏性泥石流冲刷沟床的深度与沟床坡度成正相关,与泥石流容重或沟床物质容重成负相关;沟床平均冲刷深度与沟床坡度成线性正比关系,与泥石流容重成线性反比关系,与沟床物质容重的自然对数成线性反比关系。最后,分析得到黏性泥石流沟床平均冲刷深度经验公式。%  It is very common that the buildings and engineering facilities collapsed due to the instability of their foundations caused by viscous debris flow in eroding gully bed. In order to explore the law of gully bed erosion depth,three groups of flume experiments were carried out. Experimental results show that (1) Erosion depth of gully bed mainly influenced by slope gradient,density of debris flow and density of gully bed materials;(2) Erosion depth of gully bed increases with increase of slope gradient and decreases with increase of density of debris flow or density of gully bed materials;(3) Average erosion depth of gully bed increases with the increase of slope gradient and has a linear relation, decreases with the increase of density of debris flow and has a linear relation and the increase of density of gully bed materials and has a logarithmic relationship. Finally,a prediction formula of the average erosion depth of gully bed due to vis⁃cous debris flow based on the experiment data was posed.

  14. Experimental investigation of ash deposits on convection heating surfaces of a circulating fluidized bed municipal solid waste incinerator.

    Science.gov (United States)

    Tang, Zhi; Chen, Xiaoping; Liu, Daoyin; Zhuang, Yaming; Ye, Minghua; Sheng, Hongchan; Xu, Shaojuan

    2016-10-01

    Incineration of municipal solid waste (MSW) is a waste treatment method which can be sustainable in terms of waste volume reduction, as well as a source of renewable energy. During MSW combustion, increased formation of deposits on convection heating exchanger surfaces can pose severe operational problems, such as fouling, slagging and corrosion. These problems can cause lower heat transfer efficiency from the hot flue gas to the working fluid inside the tubes. A study was performed where experiments were carried out to examine the ash deposition characteristics in a full-scale MSW circulating fluidized bed (CFB) incinerator, using a newly designed deposit probe that was fitted with six thermocouples and four removable half rings. The influence of probe exposure time and probe surface temperature (500, 560, and 700°C) on ash deposit formation rate was investigated. The results indicate that the deposition mass and collection efficiency achieve a minimum at the probe surface temperature of 560°C. Ash particles are deposited on both the windward and leeward sides of the probe by impacting and thermophoretic/condensation behavior. The major inorganic elements present in the ash deposits are Ca, Al and Si. Compared to ash deposits formed on the leeward side of the probe, windward-side ash deposits contain relatively higher Ca and S concentrations, but lower levels of Al and Si. Among all cases at different surface temperatures, the differences in elemental composition of the ash deposits from the leeward side are insignificant. However, as the surface temperature increases, the concentrations of Al, Si, K and Na in the windward-side ash deposits increase, but the Ca concentration is reduced. Finally, governing mechanisms are proposed on the basis of the experimental data, such as deposit morphology, elemental composition and thermodynamic calculations.

  15. Procesamiento de oraciones ambiguas de "vía muerta" y envejecimiento: un estudio experimental ("Garden path" sentences processing and aging: An experimental study

    Directory of Open Access Journals (Sweden)

    Katia Sáez

    2011-12-01

    Full Text Available Se presentan los resultados de un estudio experimental cuyo propósito es determinar si el envejecimiento cognitivo normal afecta o no el procesamiento de oraciones ambiguas de "vía muerta" que llevan a cabo los adultos mayores. La hipótesis que se somete a prueba empírica es que la reducción de la capacidad de la memoria operativa, debido al envejecimiento cognitivo normal, produce como efecto un declive en la capacidad de procesamiento sintáctico de estructuras sintácticas ambiguas, lo que eventualmente podría afectar a la comprensión de la oración. En el experimento se compara el desempeño de 39 adultos jóvenes y 31 adultos mayores en una tarea de lectura cronometrada de oraciones que presentan ambigüedad sintáctica temporal del tipo objeto directo/sujeto ("Mientras la joven montaba el potro fue robado de las caballerizas", seguida de una tarea de comprensión. El análisis de las diferencias encontradas en los tiempos de lectura y comprensión de las oraciones no corroboran sino en forma parcial la hipótesis. (This article presents the results of an experimental study whose purpose is to determine whether normal cognitive aging affects older adult’s processing of ambiguous "garden path" sentences. The hypothesis that is tested empirically postulates that the reduction in the capacity of working memory due to normal cognitive aging produces a decline in the ambiguous garden path syntactic structure processing, which would eventually affect sentence comprehension. The experiment compares the performance of 39 young adults and 31 older adults in a timed reading comprehension task of sentences that contain direct object /subject temporary syntactic ambiguity ("Mientras la joven montaba el potro fue robado de las caballerizas", 'While the girl was riding the horse was stolen from the stables'. Each sentence was followed by a comprehension task. The analysis of the differences in reading times and sentence comprehension partially

  16. Influencia de la alimentación durante la lactancia sobre la desnutrición intergeneracional : Un estudio experimental

    OpenAIRE

    Cesani Rossi, María Florencia; Orden,Alicia Bibiana; Zucchi, Mariel; Oyhenart, Evelia Edith; Muñe, María Cristina; Pucciarelli, Héctor Mario

    2001-01-01

    La subnutrición puede considerarse como un factor intergeneracional importante en los estudios antropobiológicos de crecimiento, en la medida que puede afectar a los descendientes de sucesivas generaciones de una población sometida en estrés nutricional crónico. El objetivo del presente estudio es determinar, por medio de la experimentación, el efecto de la suplementación lactacional sobre el peso corporal en dos generaciones de ratas subnutridas. La generación parental (P) fue constituida po...

  17. Cicatrización de implantes inmediatos con carga inmediata y sin carga. Estudio experimental en perro Beagle

    OpenAIRE

    Mareque Bueno, Santiago

    2015-01-01

    Los implantes inmediatos muestran una alta tasa de éxito en numerosos estudios (Chen y cols. 2004). Así mismo, la carga inmediata de implantes oseointegrados muestra tasas de éxito parecidas a los implantes cargados de forma diferida, siempre y cuando se cumplant una serie de requisitos (Del Fabbro y col. 2006). Existen estudios clínicos que han evaluado la supervivencia y el éxito del uso combinado de ambas técnicas de forma simultánea (Crespi y cols. 2010). Sin embargo, ex...

  18. Estudio de la osteointegración y posibles alteraciones provocadas por el empleo de implantes dentales en hueso inmaduro. Estudio experimental en mini pigs

    OpenAIRE

    2016-01-01

    El empleo de implantes dentales se ha convertido en práctica habitual en la odontología humana actual, siendo su empleo cada vez más frecuente. Esto es debido tanto a los buenos resultados, como a la reducción de costes de esta técnica, lo que permite un mayor acceso al público general. El cerdo ha sido utilizado como modelo experimental en muchos trabajos de investigación, tanto en medicina humana como veterinaria. Hay multitud de artículos publicados que hacen referencia a su utilización en...

  19. Experimental investigations of flow distribution in coolant system of Helium-Cooled-Pebble-Bed Test Blanket Module

    Energy Technology Data Exchange (ETDEWEB)

    Ilić, M.; Schlindwein, G., E-mail: georg.schlindwein@kit.edu; Meyder, R.; Kuhn, T.; Albrecht, O.; Zinn, K.

    2016-02-15

    Highlights: • Experimental investigations of flow distribution in HCPB TBM are presented. • Flow rates in channels close to the first wall are lower than nominal ones. • Flow distribution in central chambers of manifold 2 is close to the nominal one. • Flow distribution in the whole manifold 3 agrees well with the nominal one. - Abstract: This paper deals with investigations of flow distribution in the coolant system of the Helium-Cooled-Pebble-Bed Test Blanket Module (HCPB TBM) for ITER. The investigations have been performed by manufacturing and testing of an experimental facility named GRICAMAN. The facility involves the upper poloidal half of HCPB TBM bounded at outlets of the first wall channels, at outlet of by-pass pipe and at outlets of cooling channels in breeding units. In this way, the focus is placed on the flow distribution in two mid manifolds of the 4-manifold system: (i) manifold 2 to which outlets of the first wall channels and inlet of by-pass pipe are attached and (ii) manifold 3 which supplies channels in breeding units with helium coolant. These two manifolds are connected with cooling channels in vertical/horizontal grids and caps. The experimental facility has been built keeping the internal structure of manifold 2 and manifold 3 exactly as designed in HCPB TBM. The cooling channels in stiffening grids, caps and breeding units are substituted by so-called equivalent channels which provide the same hydraulic resistance and inlet/outlet conditions, but have significantly simpler geometry than the real channels. Using the conditions of flow similarity, the air pressurized at 0.3 MPa and at ambient temperature has been used as working fluid instead of HCPB TBM helium coolant at 8 MPa and an average temperature of 370 °C. The flow distribution has been determined by flow rate measurements at each of 28 equivalent channels, while the pressure distribution has been obtained measuring differential pressure at more than 250 positions. The

  20. Estudio numerico y experimental del proceso de soldeo MIG sobre la aleacion 6063--T5 utilizando el metodo de Taguchi

    Science.gov (United States)

    Meseguer Valdenebro, Jose Luis

    improvement on mechanical properties in aluminum metal joint. Los procesos de soldadura por arco electrico representan unas de las tecnicas mas utilizadas en los procesos de fabricacion de componentes mecanicos en la industria moderna. Los procesos de soldeo por arco se han adaptado a las necesidades actuales, haciendose un modo de fabricacion flexible y versatil. Los resultados obtenidos numericamente en el proceso de soldadura son validados experimentalmente. Los principales metodos numericos mas empleados en la actualidad son tres, metodo por diferencias finitas, metodos por elementos finitos y metodo por volumenes finitos. El metodo numerico mas empleado para el modelado de uniones soldadas, es el metodo por elementos finitos, debido a que presenta una buena adaptacion a las condiciones geometricas y de contorno ademas de que existe una diversidad de programas comerciales que utilizan el metodo por elementos finitos como base de calculo. Este trabajo de investigacion presenta un estudio experimental de una union soldada mediante el proceso MIG de la aleacion de aluminio 6063-T5. El metodo numerico se valida experimentalmente aplicando el metodo de los elementos finitos con el programa de calculo ANSYS. Los resultados experimentales obtenidos son: las curvas de enfriamiento, el tiempo critico de enfriamiento t4/3, geometria del cordon, microdurezas obtenidas en la union soldada, zona afectada termicamente y metal base, dilucion del proceso, areas criticas intersecadas entre las curvas de enfriamiento y la curva TTP. Los resultados numericos son: las curvas del ciclo termico, que representan tanto el calentamiento hasta alcanzar la temperatura maxima y un posterior enfriamiento. Se calculan el tiempo critico de enfriamiento t4/3, el rendimiento termico y se representa la geometria del cordon obtenida experimentalmente. La zona afectada termicamente se obtiene diferenciando las zonas que se encuentran a diferentes temperaturas, las areas criticas intersecadas entre las

  1. Hydraulic design of embankment stepped chutes: a methodology based on an experimental study; Diseno hidraulico de vertedores escalonados con pendientes modernas: metodologia basada en un estudio experimental

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Carlos A; Chanson, Hubert [Universidad de Queensland (Australia)

    2007-04-15

    escalonados se usan como vertedores y/o canales para peces en presas y diques, como disipadores de energia en canales y rios, o como aireadores en plantas de tratamiento y torrentes contaminados. Diversos investigadores han estudiado el flujo en vertedores escalonados, enfocandose en estructuras de gran pendiente ({theta} {approx} 45 grados), por lo que a la fecha, el comportamiento del flujo sobre vertedores con pendientes moderadas ({theta}15 a 30 grados) no ha sido totalmente entendido. El presente articulo comprende un estudio experimental de las propiedades fisicas de flujo aire-agua sobre canales escalonados con pendientes moderadas tipicas en presas de materiales sueltos. Un extenso rango de gastos en condiciones de flujo rasante se investigo en dos modelos experimentales a gran escala (L{sub e} = 3 a 6): un canal con pendiente 3.5H:1V ({theta}16 grados) y dos alturas de escalon distintas (h = 0.1 y 0.5 m), y un canal con pendiente 2.5H:1V ({theta} 22 grados) y una altura de escalon de h = 0.1 m. Los resultados incluyen un analisis detallado de las propiedades del flujo en vertedores escalonados con pendientes moderadas y un nuevo criterio de diseno hidraulico, el cual esta basado en los resultados experimentales obtenidos.

  2. Biomass-Ash-Induced Agglomeration in a Fluidized Bed. Part 1: Experimental Study on the Effects of a Gas Atmosphere

    DEFF Research Database (Denmark)

    Ma, Teng; Fan, Chuigang; Hao, Lifang

    2016-01-01

    Fluidized beds have been widely applied to gasification and combustion of biomass. During gasification, a high temperature is preferable to increase the carbon conversion and to reduce the undesirable tar. However, the high temperature may lead to a severe agglomeration problem in a fluidized bed....... Understanding of the agglomeration in various atmospheres is crucial to optimize the design and operation conditions. This study focuses on the effects of gases on agglomeration tendency with different types of biomass, including corn straw, rice straw, and wheat straw. The biomass ash samples are mixed...

  3. 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.

  4. An experimental study of the selective oxidation of ethene in a wall cooled tubular packed bed reactor

    NARCIS (Netherlands)

    Borman, P.C.; Westerterp, K.R.

    1992-01-01

    The selective oxidation of ethene over a silver on ¿-alumina catalyst was studied in a wall cooled tubular reactor. Temperatures were measured inside the bed at different axial and radical positions as well as the overall conversion and selectivity. Locally measured temperatures vary after repacking

  5. Full-Scale Experimental Investigation to Quantify Building Component Ignition Vulnerability from Mulch Beds Attacked by Firebrand Showers.

    Science.gov (United States)

    Manzello, Samuel L; Suzuki, Sayaka; Nii, Daisaku

    2017-03-01

    Structure ignition by wind-driven firebrand showers is an important fire spread mechanism in large outdoor fires. Experiments were conducted with three common mulch types (shredded hardwood mulch, Japanese Cypress wood chips, and pine bark nuggets) placed adjacent to realistic-scale reentrant corners. In the first series of experiments, mulch beds were placed adjacent to a re-entrant corner constructed with wood studs and lined with oriented strand board (OSB) as the sheathing. The premise behind conducting experiments with no siding treatments applied was predicated on the notion that bare OSB mulch contact would be a worst-case scenario, and therefore, a wall assembly in the most vulnerable state to mulch ignition. In the second series of experiments, vinyl siding was applied to the re-entrant corner assemblies (wood studs/OSB/moisture barrier/vinyl siding), and the influence of vertical separation distance (102 mm or 203 mm) on wall ignition from adjacent mulch beds was determined. The vertical separation distance was maintained by applying gypsum board to the base of the re-entrant corner. The siding itself did not influence the ignition process for the mulch beds, as the mulch beds were the first to ignite from the firebrand showers. In all experiments, it was observed that firebrands produced smoldering ignition in the mulch beds, this transitioned to flaming ignition, and the re-entrant corner assembly was exposed to the flaming mulch beds. With no siding treatments applied, the flaming mulch beds ignited the re-entrant corner, and ignition was observed to propagate to the back side of re-entrant corner assembly under all wind speeds (6 m/s to 8 m/s). With respect to the re-entrant corners fitted with vinyl siding, the mulch type, vertical separation distance, and wind speed were important parameters as to whether flaming ignition was observed to propagate to the back-side of a reentrant corner assembly. Mulches clearly pose an ignition hazard to structures

  6. Estudio experimental de los perfiles conformados a frío: comparación con el Eurocódigo

    OpenAIRE

    2012-01-01

    Este proyecto estudia el estudio de perfiles de acero conformados en frío según el reglamento europeo y experimental para determinar la resistencia a tracción y compresión según el Eurocodigo son analizadas dos secciones distintas, secciones C y Z a temperatura ambiente y temperatura elevada. Para una mejor compresión del tema son presentados argumentos teóricos esenciales, proceso de fabricación, ventajas e inconvenientes de la utilización de los estos perfiles, o su comportamiento estruc...

  7. Modelo experimental de la respuesta ósea a xenoinjertos de origen bovino. estudio radiográfico e histomorfométrico.

    OpenAIRE

    2011-01-01

    Objetivos: Evaluar la respuesta ósea a injertos de origen bovino insertados en tibia de conejos mediante técnicas radiográficas e histomorfométricas. Materiales y Métodos: Estudio experimental en el que se emplearon veinte conejos de Nueva Zelanda con un peso entre 3900-4500 g. Veinte injertos de hueso bovino en polvo, con un tamaño de partícula de  500-1000 mm fueron insertados en defectos óseos de 4mm de diámetro en la metáfisis proximal de la tibia derecha, y veinte defectos con las mismas...

  8. Sobre la Síntesis, Estructura y Reactividad de Complejos Metal-Carbeno: un Estudio Teórico-Experimental

    OpenAIRE

    Fernández López, Israel

    2005-01-01

    El trabajo realizado en esta tesis doctoral” se enmarca dentro del campo de la química organometálica y su aplicación al desarrollo de nuevos procesos en síntesis orgánica. Dicho trabajo se ha centrado en el estudio de complejos metal-carbeno de tipo Fischer, sustratos de probada versatilidad en síntesis orgánica. La presente tesis doctoral estudia, tanto desde un punto de vista teórico como experimetal, procesos fotoquímicos, sintéticos y estructurales de este tipo de complejos organometálic...

  9. El desarrollo del niño desnutrido : un estudio experimental sobre alimentación temprana

    OpenAIRE

    Ernesto Pollitt; John Durnin; Tom Aitchison; Mahdi Husaini; Abas Jahari; Beat Schürch

    2000-01-01

    El estudio fue un ensayo clínico aleatorio en el que participaron dos cohortes de niños (12 y 18 meses) indonesios en riesgo nutricional; hubo tres suplementos dietéticos: energía alta y micronutrientes; leche descremada y micronutrientes; y leche descremada. Se puso a prueba la hipótesis de que un suplemento de energía y micronutrientes administrado tempranamente, previene el retardo en el crecimiento físico y el desarrollo mental. Se obtuvo que el efecto de la suplementación con energía y m...

  10. Estudio experimental del aprovechamiento del calor residual de un MACI para generar hidrógeno catalíticamente

    OpenAIRE

    Rejas García, Albert

    2014-01-01

    A lo largo de este proyecto se realiza el estudio de la posibilidad de la utilización de energía residual, concretamente el calor disipado por los gases de escape de un motor de combustión, para el reformado catalítico de hidrógeno. Es decir, la obtención de un vector energético a partir de energía no aprovechada, lo que significa un aumento de la eficiencia del sistema. Para realizar el reformado se han valorado diferentes catalizadores: uno de cobalto y uno de rodio-paladio, así...

  11. Experimental study on the reuse of spent rapidly hydrated sorbent for circulating fluidized bed flue gas desulfurization.

    Science.gov (United States)

    Li, Yuan; Zheng, Kai; You, Changfu

    2011-11-01

    Rapidly hydrated sorbent, prepared by rapidly hydrating adhesive carrier particles and lime, is a highly effective sorbent for moderate temperature circulating fluidized bed flue gas desulfurization (CFB-FGD) process. The residence time of fine calcium-containing particles in CFB reactors increases by adhering on the surface of larger adhesive carrier particles, which contributes to higher sorbent calcium conversion ratio. The circulation ash of CFB boilers (α-adhesive carrier particles) and the spent sorbent (β and γ-adhesive carrier particles) were used as adhesive carrier particles for producing the rapidly hydrated sorbent. Particle physical characteristic analysis, abrasion characteristics in fluidized bed and desulfurization characteristics in TGA and CFB-FGD systems were investigated for various types of rapidly hydrated sorbent (α, β, and γ-sorbent). The adhesion ability of γ-sorbent was 50.1% higher than that of α-sorbent. The abrasion ratio of β and γ-sorbent was 16.7% lower than that of α-sorbent. The desulfurization abilities of the three sorbent in TGA were almost same. The desulfurization efficiency in the CFB-FGD system was up to 95% at the bed temperature of 750 °C for the β-sorbent.

  12. [Force-based local navigation in robot-assisted implantation bed anlage in the lateral skull base. An experimental study].

    Science.gov (United States)

    Plinkert, P K; Federspil, P A; Plinkert, B; Henrich, D

    2002-03-01

    Excellent precision, miss of retiring, reproducibility are main characteristics of robots in the operating theatre. Because of these facts their use for surgery in the lateral scull base is of great interest. In recent experiments we determined process parameters for robot assisted reaming of a cochlea implant bed and for a mastoidectomy. These results suggested that optimizing parameters for thrilling with the robot is needed. Therefore we implemented a suitable reaming curve from the geometrical data of the implant and a force controlled process control for robot assisted reaming at the lateral scull base. Experiments were performed with an industrial robot on animal and human scull base specimen. Because of online force detection and feedback of sensory data the reaming with the robot was controlled. With increasing force values above a defined limit feed rates were automatically regulated. Furthermore we were able to detect contact of the thrill to dura mater by analyzing the force values. With the new computer program the desired implant bed was exactly prepared. Our examinations showed a successful reaming of an implant bed in the lateral scull base with a robot. Because of a force controlled reaming process locale navigation is possible and enables careful thrilling with a robot.

  13. Estudio mecánico e hidrodinámico de un reactor de gasificación de lecho fluidizado. // Mechanic and hydrodynamic study of a fluidized bed gasification reactor.

    Directory of Open Access Journals (Sweden)

    W. Rosales

    2008-01-01

    Full Text Available Se realizó una simulación mediante Elementos Finitos y CFD de un prototipo de gasificador experimental a partir de unageometría propuesta. Se abordan aspectos termomecánicos, al calcularse las deformaciones originadas en el equipo,producto de su peso, en las condiciones de emplazamiento y la carga térmica a la que se somete. También se considera elflujo multifásico gas-sólido presente en el lecho fluidizado, se determina el rango de presiones y velocidades de trabajo deldispositivo, y se estudia la evolución del flujo. Para ello se utiliza el modelo de fuerza de arrastre y presión de sólido deGidaspow, así como los criterios de velocidad mínima de fluidización de Wen & Yu y Kunii & Levenspiel.Palabras claves: Gasificación, lecho fluidizado, CFD, FEM, flujo multifásico.______________________________________________________________________________Abstract.A Finite Element and CFD simulations were conducted to a prototype of experimental gasifier, starting from a proposedgeometry. Thermomechanic aspects are briefed, calculating the reactor deformation, due to its weight and the thermic load.The gas-solid multiphase flow, present on the fluidized bed was also considered, the working range for the pressure andvelocity fields were determined and the flow evolution was studied. The drag force and solid pressure models byGidaspow, and the minimum fluidization velocity criteria, by Wen & Yu and Kunii & Levenspiel were used.Key words: gasification, fluidized bed, CFD, Finite Element, Multiphase Flow.

  14. Estudio experimental de la aglomeración de partículas en un lecho fluidizado

    OpenAIRE

    Prada Díaz, Ángel de

    2014-01-01

    Muchos han sido los estudios y aplicaciones realizadas acerca del fenómeno de la fluidización de partículas sólidas desde el primer cuarto del siglo pasado. Para establecer una primera toma de contacto con el fenómeno, podemos definir éste en términos de un simple experimento en el que un lecho de partículas sólidas es mantenido en suspensión por una corriente de gas o líquido que pasa a través de ellas. El comportamiento de dichas partículas guarda ciertas similitudes con el comportamiento d...

  15. Experimental Study of Stabilized Soil Utilizing Circulating Fluidized Bed Combustion Desulfurization Ash with Carbide Slag and Desulfurization Gypsum

    OpenAIRE

    2015-01-01

    This paper discusses the feasibility of preparing soil stabilizer which is circulating fluidized bed combustion ash-based, supplemented with carbide slag and desulfurization gypsum, composed entirely of complete industrial wastes. The results show that CFBC ash has better pozzolanic activity than fly ash. When stabilizer total content is 10% and the ratio of CFBC ash : carbide slag : desulfurization gypsum is 7.2 : 1.8 : 1, compressive strength of stabilized soil can reach the maximum of 2.12...

  16. An Experimental Study of Liquid-Solid Flow in a Circulating Fluidized Bed of Varying Liquid Viscosity

    Directory of Open Access Journals (Sweden)

    nirmala sundaram

    2015-01-01

    Full Text Available Hydrodynamics plays a major role in the design of an industrial liquid-solid circulating fluidized bed (LSCFB system. Till date, research investigations have been carried out with tap water as a liquid phase in an LSCFB. But still there is a limited understanding regarding the circulation of particles in an LSCFB with viscous fluids. The aim of our study was to characterize the hydrodynamics in an LSCFB with varying viscosity. Experiments were conducted in a fluidized bed riser of 0.1 m diameter by 2.4 m height with different viscous liquids to study the effects of the operating parameters, namely, primary velocity, secondary velocity, and total velocity, on the hydrodynamic characteristics of the LSCFB with reference to its solid holdup, solid circulation rate, and particle velocity. Experiments were conducted using water and glycerol at different concentrations, and the solid particles (sand and resin of different densities, but same diameter were used in the experiment. The results indicate that the solid holdup in the riser was axially uniform for viscous liquids, which increased with an increase in auxiliary velocity. The average solid holdup decreased with an increase in total velocity, and it increased with an increase in liquid viscosity as the critical transitional velocity decreased with an increase in viscosity. The solid circulation rate was found to be increased with increased total velocity, auxiliary velocity, and viscosity.

  17. El desarrollo del niño desnutrido : un estudio experimental sobre alimentación temprana

    Directory of Open Access Journals (Sweden)

    Ernesto Pollitt

    2000-12-01

    Full Text Available El estudio fue un ensayo clínico aleatorio en el que participaron dos cohortes de niños (12 y 18 meses indonesios en riesgo nutricional; hubo tres suplementos dietéticos: energía alta y micronutrientes; leche descremada y micronutrientes; y leche descremada. Se puso a prueba la hipótesis de que un suplemento de energía y micronutrientes administrado tempranamente, previene el retardo en el crecimiento físico y el desarrollo mental. Se obtuvo que el efecto de la suplementación con energía y micronutrientes en los bebés de 12 meses fue superior al efecto producido por la suplementación con micronutrientes y leche descremada. Los efectos en el grupo que comenzó a los 18 meses fueron menores. Hubo una interacción entre los efectos. Los resultados sugieren que este tipo de intervención en niños desnutridos debe iniciarse durante el primer año de vida.

  18. Experimental Study of Stabilized Soil Utilizing Circulating Fluidized Bed Combustion Desulfurization Ash with Carbide Slag and Desulfurization Gypsum

    Directory of Open Access Journals (Sweden)

    Dezhi Shao

    2015-01-01

    Full Text Available This paper discusses the feasibility of preparing soil stabilizer which is circulating fluidized bed combustion ash-based, supplemented with carbide slag and desulfurization gypsum, composed entirely of complete industrial wastes. The results show that CFBC ash has better pozzolanic activity than fly ash. When stabilizer total content is 10% and the ratio of CFBC ash : carbide slag : desulfurization gypsum is 7.2 : 1.8 : 1, compressive strength of stabilized soil can reach the maximum of 2.12 MPa at the age of 28 d of curing. Stabilizer can meet the strength requirements of cement-soil mixing pile composite foundation and cement-soil mixing pile waterproof curtain.

  19. Experimental study and simulation of mass distribution of the covering layer of soybean seeds coated in a spouted bed

    Directory of Open Access Journals (Sweden)

    Duarte C. R.

    2004-01-01

    Full Text Available In previous work, it was observed that the covering of soybean seeds with bacteria and micronutrients enhances vigorous growth of the plant thereby avoiding use of ammoniacal fertilizers. In the spouted bed covering can be done by pulverization of the coater slurry on the soybean seeds using a pneumatic atomizer. The optimum thickness of the cover allows the fundamental gaseous interchanges for germination and provides the ideal conditions for bacterium activity. The objective of this work was to study the influence of the process variables on thickness of the cover. A simulation of the mass distribution of seeds was obtained using a population balance model. Through the results obtained the operational conditions under which the coating layer distribution were determined has the greatest uniformity.

  20. Health impact and cost-effectiveness of a private sector bed net distribution: experimental evidence from Zambia

    Science.gov (United States)

    2013-01-01

    Background Relatively few programmes have attempted to actively engage the private sector in national malaria control efforts. This paper evaluates the health impact of a large-scale distribution of insecticide-treated nets (ITNs) conducted in partnership with a Zambian agribusiness, and its cost-effectiveness from the perspective of the National Malaria Control Programme (NMCP). Methods The study was designed as a cluster-randomized controlled trial. A list of 81,597 cotton farmers was obtained from Dunavant, a contract farming company in Zambia’s cotton sector, in December 2010. 39,963 (49%) were randomly selected to obtain one ITN each. Follow-up interviews were conducted with 438 farmers in the treatment and 458 farmers in the control group in June and July 2011. Treatment and control households were compared with respect to bed net ownership, bed net usage, self-reported fever, and self-reported confirmed malaria. Cost data was collected throughout the programme. Results The distribution effectively reached target beneficiaries, with approximately 95% of households in the treatment group reporting that they had received an ITN through the programme. The average increase in the fraction of household members sleeping under an ITN the night prior to the interview was 14.6 percentage points (p-value <0.001). Treatment was associated with a 42 percent reduction in the odds of self-reported fever (p-value <0.001) and with a 49 percent reduction in the odds of self-reported malaria (p-value 0.002). This was accomplished at a cost of approximately five US$ per ITN to Zambia’s NMCP. Conclusions The results illustrate that existing private sector networks can efficiently control malaria in remote rural regions. The intra-household allocation of ITNs distributed through this channel was comparable to that of ITNs received from other sources, and the health impact remained substantial. PMID:23506170

  1. Estudio Experimental y por Análisis de Elementos Finitos del Factor de Concentrador de Esfuerzo Producido por un Agujero en una Placa Plana

    Directory of Open Access Journals (Sweden)

    Fernando Roldan

    2002-01-01

    Full Text Available En el presente artículo se propone un método de trabajo basado en el Análisis por Elementos Finitos (FEA y la Validación Experimental para el estudio de esfuerzos en medios elásticos. La formulación y desarrollo del análisis de los concentradores de esfuerzos sobre una placa de espesor constante sometida a esfuerzo en sus extremos, fueron verificados mediante la teoría de la elasticidad, experimentalmente y por el análisis de elementos finitos. La utilización de los métodos numéricos se caracterizó por su eficacia en la solución del problema planteado, proporcionando información confiable sobre los esfuerzos y deformaciones rápidamente y a muy bajo costo, comparada con los métodos experimentales

  2. Experimental study of movements respiratory conditions acceptable in radiotherapy techniques advanced; Estudio experimental de las condiciones de movimiento respiratorio aceptables en tecnicas de radioterapia avanzada

    Energy Technology Data Exchange (ETDEWEB)

    Carrasco de Fez, P.; Ruiz Martinez, A.; Ruiz Martinez, A.; Jornet Sala, N.; Latorre Musoll, A.; Eudaldo Puell, T.; Ribas Morales, M.

    2015-07-01

    The aim is Determine experimentally in what conditions the movement of the PTV produces uncertainties unacceptable in the various stages of the treatment radiotherapy, from the acquisition of imagens 4D to the irradiation. (Author)

  3. The experimental investigation on the performance of a low temperature waste heat-driven multi-bed desiccant dehumidifier (MBDD) and minimization of entropy generation

    KAUST Repository

    Myat, Aung

    2012-06-01

    We present the experimental investigation on the performance of multi-bed desiccant dehumidification system (MBDD) using a thermodynamic framework with an entropy generation analysis. The cyclic steady state performance of adsorption-desorption processes at the assorted heat source temperatures, and typical ambient humidity conditions was carried out. MBDD unit uses type-RD silica gel pore surface area with of 720 m 2/g. It has a nominal diameter range of 0.4 to 0. 7 mm. The key advantages of MBDD are: (i) it has no moving parts rendering less maintenance, (ii) energy-efficient means of dehumidification by adsorption process with low temperature heat source as compared to the conventional methods, (iii) although it is a pecked bed desiccant, a laminar chamber is employed by arranging the V-shaped configuration of heat exchangers and (iv) it is environmental friendly with the low-carbon footprint. Entropy generation analysis was performed at the assorted heat source temperatures to investigate the performance of MBDD. By conducting the entropy minimization, it is now able to locate the optimal operating conditions of the system while the specific entropy generation is found to be minimal. This analysis shows that the minimization of entropy generation in the dehumidification cycle leads to the maximization of COP in the MBDD and thus, higher delivery of useful effects at the same input resources. © 2011 Elsevier Ltd. All rights reserved.

  4. An Experimental Study on Axial Temperature Distribution of Combustion of Dewatered Poultry Sludge in Fluidized bed combustor

    Directory of Open Access Journals (Sweden)

    Abbas A.H.

    2016-01-01

    Full Text Available A laboratory scale bubbling fluidized bed combustor was designed and fabricated to study the combustion of dewatered poultry sludge at different operational parameters. This paper present a study on the influence of equivalent ratio, secondary to primary air ratio and the fuel feed rate on the temperature distribution along the combustor. The equivalent ratio has been changed between 0.8 to 1.4% under poultry sludge feed rate of 10 kg/h and from 0.8 to 1 under poultry sludge feed rate of 15 kg/h. The secondary to primary air ratio was varied from 0.1 to 0.5 at 0.65 m injection height and 1.25 equivalent ratio. The results showed that these factors had a significant influence on the combustion characteristics of poultry sludge. The temperature distribution along the combustor was found to be strongly dependent on the fuel feed rate and the equivalent ratio and it increased when these two factors increased. However, the secondary air ratio increased the temperature in the lower region of the combustor while no significant effect was observed at the upper region of the combustor. The results suggested that the poultry sludge can be used as a fuel with high thermal combustor efficiency.

  5. Experimental investigation of mobile small-scale liquefier for 10000 NM3/D of coal bed methane gas

    Science.gov (United States)

    Sun, Zhaohu; Wu, J. F.; Gong, Maoqiong; Guo, Ping

    2012-06-01

    There is a growing recognition that unconventional sources of gas, such as shale gas, coal bed methane (CBM) and deep tight gas will contribute a significant component of future gas supplies as technologies evolve. In recent years, the interest in such source of gas utilization technologies based on small-scale LNG production has been rising steeply. In this paper, a mobile liquefier prototype for 10000 Nm3/d of CBM has been designed, constructed and tested. It has two cascade refrigeration systems. The high-temperature refrigeration system will pre-cool the resource gas to 5oC, and the low-temperature refrigeration system will continue to cool the resource gas to the liquefied point with a Mixed Refrigerant Cycle (MRC). The kernel compressor is a conventional oil-lubricated air-conditioning compressor with the discharge pressure of 2.0 MPa. The main heat exchanger is plate-fin heat exchanger with four passages. A series of experiments have been done on the prototype liquefier at different resource gas pressures and environmental temperatures. It is less than one hour from the start of the equipment to the existence of LNG. The maximum production of LNG is about 20 m3/d when a stream of about 12500 Nm3/d of pure CBM at a process pressure of 1.3 MPa is liquefied. The energy consumption of liquefying 1 Nm3 methane is 0.612 kWh.

  6. Estudio histomorfológico de la capacidad de regeneración ósea del plasma rico en plaquetas, médula ósea y fosfato tricálcico: estudio experimental en cerdos “regeneración ósea en cirugía experimental en cerdos”

    OpenAIRE

    Castañeda Vega, Paul; López López, José, 1958-; Chimenos Küstner, Eduardo; Manzanares Céspedes, Cristina; Muñoz Sánchez, Juan; Jané Salas, Enric; Álvarez López, José; Gimeno Sanding, Alvaro

    2010-01-01

    Objetivo: Se valora histomorfológicamente la capacidad de regeneración ósea del plasma rico en plaquetas, a distintas concentraciones, y el extracto de médula ósea rico en plaquetas, en comparación con β-fosfato tricálcico. Material y Metodo: Se realiza un trabajo experimental en 8 cerdos, a los que se les practican trepanaciones mandibulares para colocar los materiales a estudio. Las muestras obtenidas se observan mediante microscopio electrónico y se realizan fotografías sistemá...

  7. Estudio experimental y teórico de mezclas líquidas binarias formadas por 1-alcoholes y ciclohexilamina

    OpenAIRE

    Sanz del Soto, Luis Felipe

    2016-01-01

    Mediante la medida experimental de la densidad, viscosidad, índice de refracción y permitividad a tres temperaturas (293.15, 298.15 y 303.15 K) y el cálculo de diferentes magnitudes derivadas, se ha procedido a estudiar las interacciones intermoleculares que se producen en las mezclas líquidas binarias de 1-alcohol (metanol, 1-propanol, 1-butanol, 1-heptanol y 1-decanol) con la ciclohexilamina. Departamento de Física Aplicada Doctorado en Física

  8. Estudio experimental sobre el comportamiento del hierro austemperado nitrurado (adi a la fatiga de contacto. // Experimental study to contact fatigue behavior of nitrided-austempered ductile iron.

    Directory of Open Access Journals (Sweden)

    C. Figueroa

    2001-10-01

    Full Text Available En el presente trabajo se muestra un estudio sobre el hierro fundido austemperado nitrurado sometido a pruebas de fatiga decontacto. El mismo se austenitizó y austemperó a las temperaturas de 900 y 3800C respectivamente, seleccionándose enambos casos un tiempo de 2 horas. Después se le aplicó un proceso de nitruración gaseosa a 5700C durante 6 horas.Las experiencias fueron realizadas en una máquina para el ensayo de fatiga de contacto con discos. Las presionesHertzianas utilizadas fueron de 1.73, 1.78, 2.04, 2.41, 2.46 y 2.71 GPa.La composición de fases se determinó utilizando la difracción de rayos X, evidenciándose la presencia de los compuestos e(Fe2-3N y g¢ (Fe4N. Los defectos tales como: pittings spalls y grietas fueron observados por medio de la microscopíaelectrónica de barrido (SEM. Los resultados indicaron que la capa nitrurada entre 5 y 6 micras de espesor desaparece bajola acción de las presiones de contacto. Por otra parte se pudo detectar una disminución de la resistencia a la fatiga en el ADInitrurado cuando fueron utilizadas bajas presiones Hertzianas También se comprobó que los nódulos de grafito actúancomo barreras a la propagación de grietas.Palabras claves: Fatiga de contacto, Capa nitrurada, hierro dúctil austemperado, máquina de fatiga condiscos, rayos X._____________________________________________________________________AbstractThis paper presents a study on the behavior of nitrided austempered ductile iron (ADI under contact fatigue tests. ADI wasaustenitized at 9000C for 2 hours and austempered at 380oC for 2 hours. Later, the ADI was nitrided at 570oC for a periodof 6 hours.The contact fatigue tests were carried out using a disc test machine. Hertzian pressures of 1.73, 1.78, 2.04, 2.41, 2.46 and2.71 were used during the tests.The phase composition of nitride layer was determined using X-ray analysis, which detected the presence of the e and g¢phases. The pitting, spalls and cracks that appeared

  9. Estudio cuasi-experimental sobre actitudes de educación ambiental en Educación Física

    Directory of Open Access Journals (Sweden)

    Antonio Baena-Extremera

    2014-01-01

    Full Text Available El objetivo de este trabajo ha sido analizar las diferencias en relación a la preocupación ecológica y preocupación ambiental entre un grupo de alumnado de secundaria que permaneció varios días en una granjaescuela realizando trabajos propios del entorno rural y otro grupo que permaneció el mismo tiempo en otro entorno rural practicando actividades deportivas de aventura. La muestra fue de 102 alumnos de 4º curso de Educación Secundaria Obligatoria de España, con edades comprendidas entre 15 y 16 años [media (M =15.34; desviación típica (DT = .70], siendo 50 chicos y 52 chicas. Se utilizó un cuestionario compuesto por la Escala de Preocupación Ecológica y la Escala de Preocu- pación Ambiental, realizándose dos pretest y un postest con comparaciones con Anova entre grupo control y experimental. Los resultados demuestran una mejoría en ambas escalas para ambos grupos, siendo mayor para el grupo de la granja-escuela. Los datos finalmente son discutidos.

  10. Experimental Study of Packing and Flow Resistance of Sinter Particle Packed Bed%大颗粒填充床堆积和阻力特性研究

    Institute of Scientific and Technical Information of China (English)

    刘柏谦; 谭培来; 王立刚

    2012-01-01

    Characteristics of morphology,packing and flow resistance of large size sinter particle and its packed bed have been studied experimentally.It has been proved that particle morphology has real effect on packing feature in flow and pressure drop or resistant coefficient.The results show: firstly,the smaller the particle size,the higher particle sphericity;secondly,it has different porosity distribution for the same group of particle according to imagine analysis result;and the thirdly,porosity distribution has some difference in space which leads to odd resistance coefficient or pressure drop.In the maximum gas velocity of the experiment study,a linear relationship between pressure drop and bed height was seen,but it did not exist when operation gas velocity decreases.%试验研究了市售烧结矿颗粒的形貌特征及其构成的密堆积填充床特征.研究显示颗粒形貌对填充床堆积特性、流体穿过填充床的流动特性的影响确实存在.研究发现:烧结矿颗粒相对规则,颗粒越小球形度越高;相同烧结矿颗粒不同密堆积的空间空隙分布不同;操作阻力或压降测量显示了奇怪的数据,即阻力系数先升后降;试验范围内,最高操作速度下压降与床高成线性关系,速度降低后这种线性关系不复存在.

  11. Experimental study of the burned of nuclear fuel by the gamma spectroscopy method; Estudio experimental del quemado de combustible nuclear por el metodo de espectrometria gamma

    Energy Technology Data Exchange (ETDEWEB)

    Amador V, P.

    2009-07-01

    Accurate information on nuclear fuel burnup is of vital importance in reactor operation, fuel management and fuel-characteristics studies. Conventionally fuel management of the TRIGA III Reactor from the National Institute of Nuclear Research (ININ) is done through the thermal balance method (management) of the power generated during reactor operation, since it is known that with 1.24 grams of {sup 235}U is possible to generate a power or 1 MW per day during the reactor operation. On the other hand, it is possible to calculate the operation time in days during a power of 1 MW with the help of the data registered in logs. With the information just mentioned one can calculate the quantity of {sup 235}U consumed in the fuel during a complete period of irradiation. In order to compare and prove that the burnup values, calculated through the thermal balance method, are correct, the ININ implemented, for the first time, the gamma-ray spectroscopy method as an experimental technique to calculate the burnup of several fuel elements. Gamma-ray spectroscopy is a nondestructive method, so that the integrity of the fuel element is not affected which is of great importance. Since there is a direct relation between the activity of {sup 137}Cs contained in the fuel elements and a series of constants which are unique for the radioisotope and for the high resolution system, the problem just simplifies in measuring the {sup 137}Cs activities. Furthermore the {sup 137}Cs concentration equation was developed theoretically and I wrote a computer program (AMAVAL) in Fortran. The task of this program is to calculate the concentrations and the activity through the use of the equation just mentioned and the history of each fuel element. The purpose of this is to compare and validate the experimental activities with the theoretical ones for each fuel element. (Author)

  12. Experimental study and numerical simulation of axial solids distribution in fluidized bed boilers; Vertikaalisten kiintoainepitoisuuksien analysointi ja simulointi kiertoleijukattilassa

    Energy Technology Data Exchange (ETDEWEB)

    Kallio, S. [Aabo Akademi, Turku (Finland). Inst. of Heat Engineering

    1997-10-01

    The project has concentrated on the study of the parameters affecting the drag correlations by examining the behaviour of the axial density profiles and especially the steady-state regions in different flow conditions both experimentally and theoretically. The empirical data analysed in this work is collected from hot conditions in a CFB pilot scale combustor. The data consists of pressure profiles and other macroscopic measurements from different flow conditions. In the analysis of the data and in the modelling work empirical methods such as neural network modelling have been used. The results show that the drag correlations written for cold conditions can be adapted to hot conditions by taking into account the change in the terminal velocity of a single particle. (orig.)

  13. Intensification of interfacial mass, heat & momentum transfer in high-G fluidized beds in vortex chambers : experimental & theoretical study of potential applications

    OpenAIRE

    Eliaers, Philippe

    2014-01-01

    Vortex chambers can be used for the generation of rotating fluidized beds. High-G operation allows eliminating many of the limitations faced in conventional fluidized beds. In particular, interfacial transfer of mass, heat and momentum can be significantly intensified. This opens perspectives for increasing the efficiency of some existing fluidized bed processes, but also for developing novel processing routes. Two processes were studied in this context: 1. Biomass drying is frequently carrie...

  14. HTR-PROTEUS PEBBLE BED EXPERIMENTAL PROGRAM CORES 9 & 10: COLUMNAR HEXAGONAL POINT-ON-POINT PACKING WITH A 1:1 MODERATOR-TO-FUEL PEBBLE RATIO

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess

    2014-03-01

    PROTEUS is a zero-power research reactor based on a cylindrical graphite annulus with a central cylindrical cavity. The graphite annulus remains basically the same for all experimental programs, but the contents of the central cavity are changed according to the type of reactor being investigated. Through most of its service history, PROTEUS has represented light-water reactors, but from 1992 to 1996 PROTEUS was configured as a pebble-bed reactor (PBR) critical facility and designated as HTR-PROTEUS. The nomenclature was used to indicate that this series consisted of High Temperature Reactor experiments performed in the PROTEUS assembly. During this period, seventeen critical configurations were assembled and various reactor physics experiments were conducted. These experiments included measurements of criticality, differential and integral control rod and safety rod worths, kinetics, reaction rates, water ingress effects, and small sample reactivity effects (Ref. 3). HTR-PROTEUS was constructed, and the experimental program was conducted, for the purpose of providing experimental benchmark data for assessment of reactor physics computer codes. Considerable effort was devoted to benchmark calculations as a part of the HTR-PROTEUS program. References 1 and 2 provide detailed data for use in constructing models for codes to be assessed. Reference 3 is a comprehensive summary of the HTR-PROTEUS experiments and the associated benchmark program. This document draws freely from these references. Only Cores 9 and 10 are evaluated in this benchmark report due to similarities in their construction. The other core configurations of the HTR-PROTEUS program are evaluated in their respective reports as outlined in Section 1.0. Cores 9 and 10 were evaluated and determined to be acceptable benchmark experiments.

  15. HTR-PROTEUS PEBBLE BED EXPERIMENTAL PROGRAM CORES 9 & 10: COLUMNAR HEXAGONAL POINT-ON-POINT PACKING WITH A 1:1 MODERATOR-TO-FUEL PEBBLE RATIO

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess

    2013-03-01

    PROTEUS is a zero-power research reactor based on a cylindrical graphite annulus with a central cylindrical cavity. The graphite annulus remains basically the same for all experimental programs, but the contents of the central cavity are changed according to the type of reactor being investigated. Through most of its service history, PROTEUS has represented light-water reactors, but from 1992 to 1996 PROTEUS was configured as a pebble-bed reactor (PBR) critical facility and designated as HTR-PROTEUS. The nomenclature was used to indicate that this series consisted of High Temperature Reactor experiments performed in the PROTEUS assembly. During this period, seventeen critical configurations were assembled and various reactor physics experiments were conducted. These experiments included measurements of criticality, differential and integral control rod and safety rod worths, kinetics, reaction rates, water ingress effects, and small sample reactivity effects (Ref. 3). HTR-PROTEUS was constructed, and the experimental program was conducted, for the purpose of providing experimental benchmark data for assessment of reactor physics computer codes. Considerable effort was devoted to benchmark calculations as a part of the HTR-PROTEUS program. References 1 and 2 provide detailed data for use in constructing models for codes to be assessed. Reference 3 is a comprehensive summary of the HTR-PROTEUS experiments and the associated benchmark program. This document draws freely from these references. Only Cores 9 and 10 are evaluated in this benchmark report due to similarities in their construction. The other core configurations of the HTR-PROTEUS program are evaluated in their respective reports as outlined in Section 1.0. Cores 9 and 10 were evaluated and determined to be acceptable benchmark experiments.

  16. Modelo Experimental de la Respuesta Ósea a Xenoinjertos de Origen Bovino. Estudio Radiográfico e Histomorfométrico.

    Directory of Open Access Journals (Sweden)

    Rafael Arcesio Delgado Ruíz

    2011-10-01

    Full Text Available Objetivos: Evaluar la respuesta ósea a injertos de origen bovino insertados en tibia de conejos mediante técnicas radiográficas e histomorfométricas. Materiales y Métodos: Estudio experimental en el que se emplearon veinte conejos de Nueva Zelanda con un peso entre 3900-4500 g. Veinte injertos de hueso bovino en polvo, con un tamaño de partícula de  500-1000 mm fueron insertados en defectos óseos de 4mm de diámetro en la metáfisis proximal de la tibia derecha, y veinte defectos con las mismas dimensiones fueron realizados como control  en la metáfisis proximal de la tibia izquierda. Los animales fueron sacrificados en grupos de cinco al cabo de 1, 2, 3, y 4 meses. Se tomaron  radiografías anteroposteriores y laterales. Las muestras fueron seccionadas y teñidas con hematoxilina-eosina y tricrómico de Masson. Resultados: Al cabo de 4 meses, las imágenes radiográficas mostraron la reparación completa de los defectos óseos sin alteraciones atribuibles a la presencia del injerto. El análisis histomorfométrico a los 4 meses mostró valores de 22.8±1.5% para el hueso nuevo, 39.4±2.3% para el material de injerto residual y 37.7±2.5% para el tejido conectivo no calcificado.  No hubo diferencias significativas en el cierre cortical con hueso bovino 98.8±1.1% comparado con los controles 99.1±0.7% al final del período de tiempo estudiado. Conclusiones: El biomaterial utilizado en este estudio mostro  ser biocompatible, osteoconductivo, poco reabsorbible y puede ser considerado como un sustituto óseo que no interfiere con el proceso normal de reparación del hueso. 

  17. Evaluation of the co-registration capabilities of a MRI/PET compatible bed in an Experimental autoimmune encephalomyelitis (EAE) model

    Energy Technology Data Exchange (ETDEWEB)

    Esposito, Giovanna, E-mail: giovanna.esposito@unito.it [Molecular and Preclinical Imaging Center, University of Torino (Italy); D' angeli, Luca; Bartoli, Antonietta [Molecular and Preclinical Imaging Center, University of Torino (Italy); Chaabane, Linda [INSPE-Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milano (Italy); Terreno, Enzo [Molecular and Preclinical Imaging Center, University of Torino (Italy)

    2013-02-21

    Positron Emission Tomography (PET) with {sup 18}F-FDG is a promising tool for the detection and evaluation of active inflammation in animal models of neuroinflammation. MRI is a complementary imaging technique with high resolution and contrast suitable to obtain the anatomical data required to analyze PET data. To combine PET and MRI modalities, we developed a support bed system compatible for both scanners that allowed to perform imaging exams without animal repositioning. With this approach, MRI and PET data were acquired in mice with Experimental autoimmune encephalomyelitis (EAE). In this model, it was possible to measure a variation of {sup 18}F-FDG uptake proportional to the degree of disease severity which is mainly related to Central Nervous System (CNS) inflammation. Against the low resolved PET images, the co-registered MRI/PET images allowed to distinguish the different brain structures and to obtain a more accurate tracer evaluation. This is essential in particular for brain regions whose size is of the order of the spatial resolution of PET.

  18. Evaluation of the co-registration capabilities of a MRI/PET compatible bed in an Experimental autoimmune encephalomyelitis (EAE) model

    Science.gov (United States)

    Esposito, Giovanna; D'angeli, Luca; Bartoli, Antonietta; Chaabane, Linda; Terreno, Enzo

    2013-02-01

    Positron Emission Tomography (PET) with 18F-FDG is a promising tool for the detection and evaluation of active inflammation in animal models of neuroinflammation. MRI is a complementary imaging technique with high resolution and contrast suitable to obtain the anatomical data required to analyze PET data. To combine PET and MRI modalities, we developed a support bed system compatible for both scanners that allowed to perform imaging exams without animal repositioning. With this approach, MRI and PET data were acquired in mice with Experimental autoimmune encephalomyelitis (EAE). In this model, it was possible to measure a variation of 18F-FDG uptake proportional to the degree of disease severity which is mainly related to Central Nervous System (CNS) inflammation. Against the low resolved PET images, the co-registered MRI/PET images allowed to distinguish the different brain structures and to obtain a more accurate tracer evaluation. This is essential in particular for brain regions whose size is of the order of the spatial resolution of PET.

  19. Gas dispersion and bubble-to-emulsion phase mass exchange in a gas-solid bubbling fluidized bed: a computational and experimental study

    NARCIS (Netherlands)

    Patil, Dhaneshwar J.; Sint Annaland, van Martin; Kuipers, J.A.M.

    2003-01-01

    Knowledge of gas dispersion and mass exchange between the bubble and the emulsion phases is essential for a correct prediction of the performance of fluidized beds, particularly when catalytic reactions take place. Test cases of single rising bubble and a bubbling fluidized bed operated with a jet w

  20. Respuesta ósea a la vitrocerámica del sistema CASiO3 - SiO2 - Ca3(PO4) : estudio experimental "in vivo"

    OpenAIRE

    Clavel Rojo, Luis

    2011-01-01

    Se presenta un estudio “in vivo”, en conejos Nueza Zelanda, de una vitrocerámica del sistema CaSiO3-[CaSiO3 - Ca3(Si3O9)]-SiO2-Ca3(PO4). Se realizaron defectos óseos epifisarios de 6 x 4´5 mm donde se implantaron cilindros del material a estudio. Los animales se distribuyeron de forma aleatoria en 5 grupos de estudio según el tiempo de implantación previo al sacrifico. Cada muestra se analizó mediante estudio radiológico, histológico y de microscopia electrónica. Los resultados obtenidos dem...

  1. Loxoscelismo en Chile: estudios epidemiológicos, clínicos y experimentales Loxoscelism in Chile: epidemiological, clinical and experimental studies

    Directory of Open Access Journals (Sweden)

    Hugo Schenone

    1989-12-01

    Full Text Available Se presenta un enfoque panorámico de estudios epidemiológicos, clínicos y experimentales referentes a Loxosceles laeta y loxoscelismo efectuados en 1955-1988 en Santiago, Chile. Se estudiaron 216 casos de loxoscelismo. Los hechos más relevantes fueron: 52,8% correspondió a mujeres; edad entre 7 meses y 78 años; 84,3% fué loxoscelismo cutáneo (LO y 15,7% loxoscelismo cutáneo-visceral (LCV; 73,6% sucedió en época calurosa; en 86,6% el accidente ocurrió en la vivienda, especialmente en dormitorios, mientras la persona dormía o se vestía. La araña fué vista en 60,2% de los casos e identificada en laboratorio como L. laeta en 17,7% (10,6% de los 216 casos. Los sitios más frecuen temente afectados fueron las extremidades con 67,6%, lancetazo urente fué el síntoma inicial más frecuente. Dolor, edema y placa livedoide, la cual posteriormente se transformaría en escara necrótica, fueron las manifestaciones locales predominantes. En LCV hematuria y hemoglobinuria fueron constantes, ictericia, fiebre y compromiso de conciencia se presentaron en la mayoría de los casos. Tratamiento: LC con antihistamínicos o corticoides inyectables, LCV con corti-coides inyectables. La condición de los pacientes en el último control fué: curación completa en 75,5%, curación con secuela cicatrizal en 8,3%, muerte en 3,7% (todos con LCV y abandono en 12,5%. Adicionalmente, se ha efectuado una serie de estudios experimentales, tanto in vivo como in vitro para esclarecer aspectos básicos sobre el veneno de L. laeta y el tratamiento del loxoscelismo.A panoramic sight of epidemiological, clinical and experimental studies, referring to Loxosceles laeta and loxoscelism, carried out in 1955-1988, in Santiago, Chile is presented. Two-hundred and sixteen cases of loxosce lism were studied. The most relevant features were: 84.3% corresponded to cutaneous loxosce lism (CD and 15.7% to viscerocutaneous loxos celism (VCD; 73.6% ocurred in hot season; in 86

  2. ESTUDIO NUMÉRICO Y EXPERIMENTAL DE LAS PROPIEDADES Y FENÓMENOS RADIATIVOS EN UNA LLAMA DE METANO (CH4 CON AIRE ENRIQUECIDO

    Directory of Open Access Journals (Sweden)

    JOSE LUIS SUÁREZ

    2011-01-01

    Full Text Available En este artículo, se presenta un estudio numérico y experimental del comportamiento de la radiación de una llama de metano con aire enriquecido con bajas concentraciones oxígeno. Se midió el flux de calor por radiación y se determinó su relación con el porcentaje de enriquecimiento del aire, permitiendo estimar las propiedades radiantes de la llama en función del enriquecimiento con oxígeno. Se utilizó aire con concentraciones de oxígeno desde 21% hasta 22,5%. La simulación se realizó con el software Fluent V6.2.16 y para resolver la ecuación de transferencia radiativa se empleó el modelo de las Ordenadas Discretas. Las propiedades radiantes de la mezcla de gases de combustión (CO, CO2 y H2O se cuantificaron empleando el modelo de la Suma Ponderada de Gases Grises (WSGGM. La experimentación se llevó a cabo empleando como combustible Gas Natural de la Guajira, un factor de aireación de 1,1 y una potencia térmica de 1,54 kW. Se utilizó un quemador de premezcla tipo Bunsen, en el que se inducía el aire, el cual a su vez es enriquecido con oxígeno proveniente de un cilindro.

  3. Empleo del parche valvado en el tratamiento de la comunicación interauricular en pacientes con hipertensión arterial pulmonar grave. Estudio cuasi-experimental

    Directory of Open Access Journals (Sweden)

    Horacio Márquez-González

    2015-10-01

    Full Text Available Introducción: La comunicación interauricular detectada en la adultez se acompaña de hipertensión arterial pulmonar. El procedimiento quirúrgico correctivo en estas condiciones presenta mayor morbilidad y mortalidad. El empleo del parche valvado evita la aparición de complicaciones tempranas.Objetivos: Analizar el comportamiento a dos años de la presión pulmonar estimada por ecocardiograma, y la función ventricular derecha en pacientes operados de cierre de comunicación interauricular con hipertensión arterial pulmonar grave con parche valvado.Método: Se realizó un estudio cuasi-experimental en 12 pacientes con comunicación interauricular de malos bordes e hipertensión arterial pulmonar grave. Se incluyeron sujetos con pruebas de reactividad positiva a oxígeno u óxido nítrico, que brindaron su consentimiento informado y se excluyeron enfermos con síndromes genéticos o hipertensión arterial pulmonar primaria. Los pacientes fueron seguidos en el posquirúrgico inmediato clínicamente, por laboratorio y por ecocardiografía a los 2, 4, 6, 12, 18 y 24 meses del posquirúrgico. Se registraron las complicaciones agregadas.Resultados: En los 12 pacientes que fueron analizados no se presentaron defunciones tempranas o tardías, la mediana de ventilación mecánica fue de 2 (1-4 días. En el seguimiento se constató mejoría significativa en: la clase funcional, las variables ecocardiográficas y la utilización de medicamentos.Conclusiones: El parche valvado unidireccional es una opción terapéutica que evita las complicaciones posquirúrgicas responsables de la mortalidad temprana.

  4. Integración de los aloinjertos óseos impregnados con alendronato: Estudio experimental. [Alendronate-impregnated­ bone­ allograft­ integration: Experimental­ study

    Directory of Open Access Journals (Sweden)

    Luis S. Ruchelli

    2014-10-01

    Full Text Available In­tro­duc­ción: el propósito de este estudio experimental es investigar la variabilidad en la reabsorción ósea de aloinjertos impregnados con alendronato respecto a aloinjertos sin impregnación con alendronato. Materiales­ y ­Métodos:­ se utilizaron 18 conejos neozelandeses, divididos en dos grupos de 9 animales cada uno. Se trabajó sobre el fémur derecho, se realizó una ventana ósea y se colocó aloinjerto con alendronato local en el grupo I y aloinjerto sin alendronato en el grupo II.­ Todos fueron sacrificados a las 10 semanas del procedimiento inicial, y se valoró el fémur operado con anatomía patológica, radiografías de frente y de perfil, y tomografía axial computarizada.­ Se evaluaron la osteointegración, la vascularización y la calidad ósea. Resultados: el estudio histológico demostró mayor osteointegración en el grupo I que en el grupo II (p = 0,003, y fenómenos bien definidos de “acoplamiento” entre el tejido óseo receptor e injertado, leve actividad osteoclástica. En el grupo II, se observó menor acoplamiento óseo (osteointegración. La evaluación de la reabsorción ósea con radiografía y tomografía computarizada no reveló una diferencia estadísticamente significativa entre ambos grupos. En el grupo I, se observó mayor osteointegración del aloinjerto (p = 0,577; no significativo. Conclusión:­ los resultados obtenidos en este trabajo experimental muestran que el alendronato local asociado a aloinjertos ayuda a mejorar la osteointegración de los aloinjertos, que es un método seguro, y que no se asocia a riesgos locales o sistémicos en conejos, aun en dosis elevadas.

  5. Estudio experimental del Sistema de Albañilería Integral en la construcción de viviendas sismorresistentes

    Directory of Open Access Journals (Sweden)

    Orta, B.

    2012-03-01

    Full Text Available This paper presents the application of the Integral Masonry System (IMS to the construction of earthquake resistant houses and its experimental study. To verify the security of this new type of building in seismic areas of the third world two prototypes have been tested, one with adobe and the other with hollow brick. In both cases it’s a two-story 6x6x6 m3 house built to scale 1/2. The tests are carried out at the Laboratory of Antiseismic Structures of the Department of Engineering, Pontifical Catholic University of Peru in Lima, in collaboration with the UPM (Technical University of Madrid. This article shows the design process of the prototypes to test, including the sizing of the reinforcements, the characteristics of the tests and the results obtained. These results show that the IMS with adobe or brick remains stable with no significant cracks faced with a severe earthquake, with an estimated acceleration of 1.8 g.

    Este artículo presenta una aplicación del Sistema de Albañilería Integral (SAI a la construcción de viviendas sismorresistentes y su estudio experimental. Para verificar su seguridad para su construcción en zonas sísmicas del tercer mundo se han ensayado dos prototipos, uno con adobe, y otro con ladrillo hueco. Se trata de una vivienda de 6x6x6 m3 y dos plantas que se construyen a escala 1/2. Los ensayos se realizaron en el Laboratorio de Estructuras Antisísmicas del Departamento de Ingeniería de la Pontificia Católica Universidad del Perú (PUCP de Lima en colaboración con la UPM (Universidad Politécnica de Madrid. Este artículo muestra el proceso de diseño de los prototipos a ensayar, incluido el dimensionado de los refuerzos, las características de los ensayos y los resultados obtenidos. Estos resultados muestran que el SAI con adobe o ladrillo permanece estable sin grietas significativas ante un sismo severo, con una aceleración estimada de 1,8 g.

  6. Estudio experimental para la valoración de la cicatrización ósea con Ácido Zoledrónico en ratas Wistar

    Directory of Open Access Journals (Sweden)

    C. Moñivas Palomero

    2015-12-01

    Full Text Available Antecedentes y objetivos: El aumento del consumo de bifosfonatos en la sociedad actual, puede incrementar el riesgo de osteonecrosis mandibular. Se realizó este estudio para valorar si tras la extracción dentaria, después de la administración subcutánea de ácido zoledrónico 7,5µg/Kg o 35 µg/Kg (Zometa® en ratas Wistar, aparecen signos clínicos, radiográficos e histopatológicos de osteonecrosis y/o inflamación. Lugar de realización: Centro Experimentación Animal del Hospital de Defensa. Material y Métodos: Estudio experimental, in vitro, randomizado, intervencionista. Se utilizaron un total de 30 ratas Wistar (adultas, sanas, repartiéndolas en tres grupos de 10 animales, según sexo, grupo y fármaco: G0: Sin tratamiento con ácido zoledrónico. G1: Con tratamiento de ácido zoledrónico 7,5µg/Kg subcutáneo una dosis en los días 1, 15 y 30. G2: Con tratamiento de ácido zoledrónico 35µg/Kg subcutáneo una dosis en los días 1, 15 y 30. En todos los grupos se realizó exodoncia del primer molar inferior derecho el día 30, sacrificando los animales a las cuatro semanas postextracción, observando clínica, histológica y radiográficamente la aparición de osteonecrosis e inflamación. Resultados: Clínicamente se observaron en un 26,6% falta de epitelización compatible con signos precoces de osteonecrosis mandibular, según criterios de la American Association of Oral Maxillofacial Súrgeons (AAOMS. Esta es dosis dependiente en 3 animales de G1 (10% y 5 animales de G2 (16,6%. Los resultados presentaron significación estadística p<0,011. Ausencia histológica y radiológica de osteonecrosis p< 0,001 e inflamación p <0,001 en todos los grupos. Conclusiones: La administración subcutánea de 7,5µg/Kg o 35µg/Kg de ácido zoledrónico durante cuatro semanas, tras la realización de una extracción dentaria, no da lugar a signos histopatológicos de osteonecrosis e inflamación (p<0,001 pero si a alteraciones cl

  7. HTR-PROTEUS Pebble Bed Experimental Program Cores 1, 1A, 2, and 3: Hexagonal Close Packing with a 1:2 Moderator-to-Fuel Pebble Ratio

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess; Barbara H. Dolphin; James W. Sterbentz; Luka Snoj; Igor Lengar; Oliver Köberl

    2012-03-01

    In its deployment as a pebble bed reactor (PBR) critical facility from 1992 to 1996, the PROTEUS facility was designated as HTR-PROTEUS. This experimental program was performed as part of an International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) on the Validation of Safety Related Physics Calculations for Low Enriched HTGRs. Within this project, critical experiments were conducted for graphite moderated LEU systems to determine core reactivity, flux and power profiles, reaction-rate ratios, the worth of control rods, both in-core and reflector based, the worth of burnable poisons, kinetic parameters, and the effects of moisture ingress on these parameters. Four benchmark experiments were evaluated in this report: Cores 1, 1A, 2, and 3. These core configurations represent the hexagonal close packing (HCP) configurations of the HTR-PROTEUS experiment with a moderator-to-fuel pebble ratio of 1:2. Core 1 represents the only configuration utilizing ZEBRA control rods. Cores 1A, 2, and 3 use withdrawable, hollow, stainless steel control rods. Cores 1 and 1A are similar except for the use of different control rods; Core 1A also has one less layer of pebbles (21 layers instead of 22). Core 2 retains the first 16 layers of pebbles from Cores 1 and 1A and has 16 layers of moderator pebbles stacked above the fueled layers. Core 3 retains the first 17 layers of pebbles but has polyethylene rods inserted between pebbles to simulate water ingress. The additional partial pebble layer (layer 18) for Core 3 was not included as it was used for core operations and not the reported critical configuration. Cores 1, 1A, 2, and 3 were determined to be acceptable benchmark experiments.

  8. HTR-PROTEUS Pebble Bed Experimental Program Cores 1, 1A, 2, and 3: Hexagonal Close Packing with a 1:2 Moderator-to-Fuel Pebble Ratio

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess; Barbara H. Dolphin; James W. Sterbentz; Luka Snoj; Igor Lengar; Oliver Köberl

    2013-03-01

    In its deployment as a pebble bed reactor (PBR) critical facility from 1992 to 1996, the PROTEUS facility was designated as HTR-PROTEUS. This experimental program was performed as part of an International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) on the Validation of Safety Related Physics Calculations for Low Enriched HTGRs. Within this project, critical experiments were conducted for graphite moderated LEU systems to determine core reactivity, flux and power profiles, reaction-rate ratios, the worth of control rods, both in-core and reflector based, the worth of burnable poisons, kinetic parameters, and the effects of moisture ingress on these parameters. Four benchmark experiments were evaluated in this report: Cores 1, 1A, 2, and 3. These core configurations represent the hexagonal close packing (HCP) configurations of the HTR-PROTEUS experiment with a moderator-to-fuel pebble ratio of 1:2. Core 1 represents the only configuration utilizing ZEBRA control rods. Cores 1A, 2, and 3 use withdrawable, hollow, stainless steel control rods. Cores 1 and 1A are similar except for the use of different control rods; Core 1A also has one less layer of pebbles (21 layers instead of 22). Core 2 retains the first 16 layers of pebbles from Cores 1 and 1A and has 16 layers of moderator pebbles stacked above the fueled layers. Core 3 retains the first 17 layers of pebbles but has polyethylene rods inserted between pebbles to simulate water ingress. The additional partial pebble layer (layer 18) for Core 3 was not included as it was used for core operations and not the reported critical configuration. Cores 1, 1A, 2, and 3 were determined to be acceptable benchmark experiments.

  9. Perfil del peso corporal en la isquemia mesentérica aguda: Estudio experimental en conejos Nueva Zelanda Body weight profile in acute mesenteric ischemia: Experimental study in New-Zealand rabbits

    Directory of Open Access Journals (Sweden)

    J. F. Guijarro Escribano

    2005-12-01

    Full Text Available Introducción y objetivos: Hay pocos trabajos de investigación que relacionen la isquemia mesentérica aguda y el peso corporal en la experimentación animal. Se pretende estudiar, si la pérdida de peso inicial, está relacionada con la magnitud de la agresión provocada por los clampajes de la arteria mesentérica superior durante 30 y 60 minutos, y si la isquemia reperfusión puede dificultar la recuperación ponderal del peso en los animales supervivientes, al final de las 11 semanas del trabajo experimental con conejos Nueva Zelanda, mediante un modelo experimental válido. Material y método: Se distribuyeron 80 animales (conejos en cuatro series de 20: serie I (control, los animales fueron pesados durante 11 semanas; serie II (operación simulada, serie III (isquemia mesentérica 30 minutos y serie IV (isquemia mesentérica 60 minutos. Provocamos la isquemia por pinzamiento de la arteria mesentérica superior. Los animales de las series II, III y IV fueron pesados 24 horas antes del procedimiento quirúrgico y semanalmente en el postoperatorio durante su supervivencia hasta completar 11 semanas. Para el análisis de los pesos, se aplicó un ANOVA enfrentando la variación del peso porcentual en función de la serie. Todos los animales fueron necropsiados para conocer la causa del fallecimiento y las lesiones histológicas de la mucosa intestinal Resultados: La serie control tuvo un incremento lineal del peso hasta el final del período de observación. Las series II, III y IV sufrieron un descenso proceinicial significativo del peso porcentual en la primera semana del postoperatorio, con una recuperación al final del estudio, pero significativamente menor con respecto a la serie control. También se han encontrado diferencias significativas en la recuperación del peso a las 11 semanas entre la serie II y las series III y IV, y entre las series isquémicas entre sí. Conclusiones: Los animales de las series II, III, y IV alcanzaron al

  10. HTR-PROTEUS PEBBLE BED EXPERIMENTAL PROGRAM CORE 4: RANDOM PACKING WITH A 1:1 MODERATOR-TO-FUEL PEBBLE RATIO

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess; Leland M. Montierth

    2014-03-01

    In its deployment as a pebble bed reactor (PBR) critical facility from 1992 to 1996, the PROTEUS facility was designated as HTR-PROTEUS. This experimental program was performed as part of an International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) on the Validation of Safety Related Physics Calculations for Low Enriched HTGRs. Within this project, critical experiments were conducted for graphite moderated LEU systems to determine core reactivity, flux and power profiles, reaction-rate ratios, the worth of control rods, both in-core and reflector based, the worth of burnable poisons, kinetic parameters, and the effects of moisture ingress on these parameters. One benchmark experiment was evaluated in this report: Core 4. Core 4 represents the only configuration with random pebble packing in the HTR-PROTEUS series of experiments, and has a moderator-to-fuel pebble ratio of 1:1. Three random configurations were performed. The initial configuration, Core 4.1, was rejected because the method for pebble loading, separate delivery tubes for the moderator and fuel pebbles, may not have been completely random; this core loading was rejected by the experimenters. Cores 4.2 and 4.3 were loaded using a single delivery tube, eliminating the possibility for systematic ordering effects. The second and third cores differed slightly in the quantity of pebbles loaded (40 each of moderator and fuel pebbles), stacked height of the pebbles in the core cavity (0.02 m), withdrawn distance of the stainless steel control rods (20 mm), and withdrawn distance of the autorod (30 mm). The 34 coolant channels in the upper axial reflector and the 33 coolant channels in the lower axial reflector were open. Additionally, the axial graphite fillers used in all other HTR-PROTEUS configurations to create a 12-sided core cavity were not used in the randomly packed cores. Instead, graphite fillers were placed on the cavity floor, creating a funnel-like base, to discourage ordering

  11. HTR-PROTEUS PEBBLE BED EXPERIMENTAL PROGRAM CORE 4: RANDOM PACKING WITH A 1:1 MODERATOR-TO-FUEL PEBBLE RATIO

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess; Leland M. Montierth

    2013-03-01

    In its deployment as a pebble bed reactor (PBR) critical facility from 1992 to 1996, the PROTEUS facility was designated as HTR-PROTEUS. This experimental program was performed as part of an International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) on the Validation of Safety Related Physics Calculations for Low Enriched HTGRs. Within this project, critical experiments were conducted for graphite moderated LEU systems to determine core reactivity, flux and power profiles, reaction-rate ratios, the worth of control rods, both in-core and reflector based, the worth of burnable poisons, kinetic parameters, and the effects of moisture ingress on these parameters. One benchmark experiment was evaluated in this report: Core 4. Core 4 represents the only configuration with random pebble packing in the HTR-PROTEUS series of experiments, and has a moderator-to-fuel pebble ratio of 1:1. Three random configurations were performed. The initial configuration, Core 4.1, was rejected because the method for pebble loading, separate delivery tubes for the moderator and fuel pebbles, may not have been completely random; this core loading was rejected by the experimenters. Cores 4.2 and 4.3 were loaded using a single delivery tube, eliminating the possibility for systematic ordering effects. The second and third cores differed slightly in the quantity of pebbles loaded (40 each of moderator and fuel pebbles), stacked height of the pebbles in the core cavity (0.02 m), withdrawn distance of the stainless steel control rods (20 mm), and withdrawn distance of the autorod (30 mm). The 34 coolant channels in the upper axial reflector and the 33 coolant channels in the lower axial reflector were open. Additionally, the axial graphite fillers used in all other HTR-PROTEUS configurations to create a 12-sided core cavity were not used in the randomly packed cores. Instead, graphite fillers were placed on the cavity floor, creating a funnel-like base, to discourage ordering

  12. Heat-transfer characteristics of flowing and stationary particle-bed-type fusion-reactor blankets

    Energy Technology Data Exchange (ETDEWEB)

    Nietert, R.E.

    1983-02-01

    The following five appendices are included: (1) physical properties of materials, (2) thermal entrance length Nusselt number variations, (3) stationary particle bed temperature variations, (4) falling bed experimental data and calculations, and (5) stationary bed experimental data and calculations. (MOW)

  13. Estudio, diseño, construcción y desarrollo experimental de un sistema de canalización aerodinámica para automovilismo

    OpenAIRE

    2015-01-01

    El proyecto está basado en mejorar la eficiencia energética en automoción. En primer lugar, he realizado un estudio teórico sobre aerodinámica e inventado un sistema con el fin de optimizar el rendimiento de los vehículos. El diseño lo simulé en el software Autodesk Flow Design, y debido al buen resultado obtenido, decidí trasladar mis estudios teóricos a la realidad, para lo cual, he construido con mis propios medios en un taller familiar 2 prototipos de coche, 6 túneles de viento y equipos ...

  14. Combining indoor residual spraying with chlorfenapyr and long-lasting insecticidal bed nets for improved control of pyrethroid-resistant Anopheles gambiae: an experimental hut trial in Benin

    Directory of Open Access Journals (Sweden)

    Ngufor Corine

    2011-11-01

    Full Text Available Abstract Background Neither indoor residual spraying (IRS nor long-lasting insecticidal nets (LLINs are able to fully interrupt transmission in holoendemic Africa as single interventions. The combining of IRS and LLINs presents an opportunity for improved control and management of pyrethroid resistance through the simultaneous presentation of unrelated insecticides. Method Chlorfenapyr IRS and a pyrethroid-impregnated polyester LLIN (WHO approved were tested separately and together in experimental huts in southern Benin against pyrethroid resistant Anopheles gambiae and Culex quinquefasciatus. The bed nets were deliberately holed with either six or 80 holes to examine the effect of increasing wear and tear on protectiveness. Anopheles gambiae were genotyped for the kdr gene to assess the combination's potential to prevent the selection of pyrethroid resistance. Results The frequency of kdr was 84%. The overall mortality rates of An. gambiae were 37% and 49% with the six-hole and 80-hole LLINs, respectively, and reached 57% with chlorfenapyr IRS. Overall mortality rates were significantly higher with the combination treatments (82-83% than with the LLIN or IRS individual treatments. Blood feeding (mosquito biting rates were lowest with the 6-hole LLIN (12%, intermediate with the 80-hole LLIN (32% and highest with untreated nets (56% with the 6-hole and 54% with the 80-hole nets. Blood feeding (biting rates and repellency of mosquitoes with the combination of LLIN and chlorfenapyr IRS showed significant improvement compared to the IRS treatment but did not differ from the LLIN treatments indicating that the LLINs were the primary agents of personal protection. The combination killed significantly higher proportions of Cx. quinquefasciatus (51%, 41% than the LLIN (15%, 13% or IRS (32% treatments. Conclusion The chlorfenapyr IRS component was largely responsible for controlling pyrethroid-resistant mosquitoes and the LLIN component was largely

  15. CFD Simulation and Experimental Analyses of a Copper Wire Woven Heat Exchanger Design to Improve Heat Transfer and Reduce the Size of Adsorption Beds

    Directory of Open Access Journals (Sweden)

    John White

    2016-02-01

    Full Text Available The chief objective of this study is the proposal design and CFD simulation of a new compacted copper wire woven fin heat exchanger and silica gel adsorbent bed used as part of an adsorption refrigeration system. This type of heat exchanger design has a large surface area because of the wire woven fin design. It is estimated that this will help improve the coefficient of performance (COP of the adsorption phase and increase the heat transfer in this system arrangement. To study the heat transfer between the fins and porous adsorbent reactor bed, two experiments were carried out and matched to computational fluid dynamics (CFD results.

  16. Estudio de "las capas del cabo ladrillero superior" en el cabo homónimo, mioceno inferior de la cuenca austral, tierra del fuego Study of "The Upper Cabo Ladrillero Beds" in the homonym locality, Lower Miocene of the Austral Basin, Tierra del Fuego

    Directory of Open Access Journals (Sweden)

    Estefanía P Tudisca

    2012-03-01

    Full Text Available En los acantilados del cabo Ladrillero, situado sobre la costa atlántica de la Isla Grande de Tierra del Fuego, afloran parte de los depósitos cuspidales que rellenan la cuenca de antepaís Austral o de Magallanes. Estos depósitos del Mioceno inferior son conocidos como "capas del Cabo Ladrillero" y "capas del Cabo San Pablo", siendo las "capas del Cabo Ladrillero superior" las analizadas en este trabajo. La zona de estudio, situada a una decena de kilómetros al norte del frente orogénico emergente (Punta Gruesa, permitió reconocer cuatro asociaciones de facies que registran depósitos gravitacionales resedimentados en un ambiente marino supra batial y una cuña deltaica progradante y somerizante hacia el noreste. Entre los rasgos más conspicuos observados en esta sucesión se destacan bancos deformados, intervalos macizos y abundantes diques clásticos, cuyo análisis estadístico indica un patrón transtensivo. Los microfósiles documentados en el área y utilizados previamente como herramienta para sostener un ambiente marino profundo provienen de niveles estratigráficos infrayacentes y corresponden a niveles de la Formación Desdémona y las capas del Cabo Ladrillero inferior, aflorantes hacia el sur de la zona de estudio. Las evidencias sedimentológicas no son concluyentes respecto de la batimetría, pero la ausencia de turbiditas clásicas, flujos hiperpícnicos, la abundancia de bancos deformados y resedimentados, restos vegetales y fragmentos de carbón son compatibles con un ambiente somero y deltaico con altas tasas de aporte y pendientes inestables antes que un ambiente marino profundo, y sugieren una historia compleja de la evolución del relleno sedimentario que no se explica meramente con los esquemas basados exclusivamente en el contenido de foraminíferos que domina en la literatura.In the cliffs of the Ladrillero cape, situated on the Atlantic coast of the Isla Grande de Tierra del Fuego, the uppermost records of the

  17. Viability study for application of combined reheater cycle (CRC) to fluidized bed combustion plants; Estudio de Viabilidad para la Aplicacion del Ciclo de Recalentamiento Combinado (CRC) a Plantas de Combustion de Lecho Fuido Atmosferico

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-01

    Basically, the project try to analyze the application viability of a first reheating in steam cycles of little power plants, useful mainly for biomass and wastes, in our case with coal blends; and a second reheating of the steam in conventional and fluidized bed combustion plants. Using in both cases the thermic energy of the exhaust gases from one gas turbine. The advantages of the CRC cycle are: (1) Reduction of the moisture in the turbine, increasing the energy efficiency and blade protection. (2) To take advantage of the waste gas energy from the gas turbine in optimum way. (3) Great operation flexibility under good efficiency results. In general, the system can use the synergy between gas, coal and waste energies with the highest global efficiency. (Author)

  18. Estudio experimental de la conducción del calor en el maquinado de materiales endurecidos con altas velocidades de corte. // Experimental study of heat conduction in mechanization with high cutting speeds of hardened materials.

    Directory of Open Access Journals (Sweden)

    L. Cardoso Brandão

    2006-01-01

    Full Text Available El trabajo trata del estudio teórico-experimental de la conducción del calor en los materiales endurecidos, usados para laproducción de moldes y matrices, al maquinarlos con altas-velocidades del corte. Los materiales utilizados son los acerosAISI P20 y AISI D2. Los ensayos se realizaron con fresas de punta esférica (Ball Nose con revestimiento (TiAlN y lasprobetas para los ensayos tienen la forma de una ¼ parte de un tubo de 28 mm de diámetro con una longitud de 100 mm.Las pruebas realizadas demuestran la variación de la temperatura en función de los diferentes sistemas de refrigeración. Seutilizo aire comprimido y aire comprimido frío, comparándose las temperaturas de las probetas con el sistema sinrefrigeración de ningún tipo. Fueron también evaluadas las deformaciones sufridas por la superficie maquinada, debido alas variaciones de temperatura teniendo en cuenta la influencia de los sistemas de refrigeración empleados.Palabras claves: Temperatura; conducción del calor; alta velocidad de corte, moldes y matrices._________________________________________________________________________Abstract.This paper deals with the theoretical-experimental study of heat conduction in hardened materials for the production ofmolds and dies using high speed cutting. The employed materials were the AISI P20 and AISI D2 steels, being the testscarried out with (TiAlN coated ball nose in a work piece with the shape of a 1/4 tube with 28 mm diameter and 100 mmlength. This investigation demonstrates the variation of temperature as a function of different cooling systems, that is,compressed air and compressed cold air. Possible geometric deformation of the machined surfaces due to these variationsin temperature for distinct cooling systems was also evaluated.Keywords: Temperature, heat exchange; high cutting speed, dies.

  19. Experimental study of the mechanisms of CO{sub 2} capture by calcium cycle under circulating fluidized bed conditions; Etude experimentale des mecanismes de capture du CO{sub 2} par cycle calcium en lit fluidise circulant

    Energy Technology Data Exchange (ETDEWEB)

    Hoteit, A

    2006-06-15

    The work undertaken in this Thesis in partnership with department R and D of ALSTOM Power Boilers, CEMEX and the ADEME, relates to the experimental study of various phenomena associated to CO{sub 2} capture under circulating fluidized bed conditions. The size of particles, temperature and the CO{sub 2} concentration have an influence on the limestone calcination reaction. The reaction of carbonation of lime is not total. During successive cycles of calcination/carbonation, the rate of carbonation obtained with hydrated lime is increasingly higher than that obtained with the lime. Under continuously reducing conditions, the decomposition of sulphates present in the bed ashes is not total. This decomposition is total under reduction/oxidation cycles. A modeling of calcination allowed to determine the intrinsic kinetic constants of calcination and carbonation. (author)

  20. Efectos del “nuevo modelo curricular” en calidad del entorno educativo, interacciones adulto-niño e inteligencia emocional: un estudio cuasi-experimental con preescolares en situación de vulnerabilidad socio-ambiental

    OpenAIRE

    Villena Spuler, Alicia del Carmen

    2012-01-01

    El objetivo fundamental de la investigación fue estudiar la Inteligencia Emocional, el Entorno Educativo y las Interacciones Adulto-Niño en un contexto de innovación educativa. La investigación se concretó en un estudio cuantitativo, descriptivo y correlacional, con diseño cuasi-experimental. La muestra intencionada estuvo formada por grupos intactos de niños preescolares provenientes de niveles socioeconómicos deprivados social y culturalmente en un establecimiento educacional en la VIII re...

  1. Estudio experimental sobre la utilización de células madre humanas en la terapia de los defectos periodontales: resultados preliminares Experimental study on the use of human stem cell therapy in periodontal defects: Preliminary results

    Directory of Open Access Journals (Sweden)

    F. Carini

    2011-08-01

    ón, con el fin de recrear la correcta anatomía estructural del periodonto perdido. Después de una fase de expansión celular, estas células se introducen en una estructura biomimética (andamios en colágeno, y se inducen a la diferenciación en sentido osteogénico. El producto final que consta de andamios y células mesenquimales diferenciadas en sentido osteoblástico, se instala por último en el defecto alveolar periodontal. La experimentación se basa en la posibilidad de utilizar células madre mesenquimales autólogas a partir de la médula ósea humana. La finalidad es la de estimular la regeneración de PDL cerca de la pared radicular y la formación de hueso nuevo sobre el PDL, beneficiándose de las técnicas de regeneración-reconstrucción ósea, de manera que se recree la correcta anatomía periodontal. Los resultados presentados en este trabajo conciernen el primer paciente tratado con esta metodología y afectarán los estudios siguientes para la prueba con una cobertura más amplia.Destruction of periodontal ligament and alveolar ridge rerorption caused by periodontal disease is the leading cause of tooth loss in adults. Therapy of advanced periodontal disease leads for a total recovery of the structure lost by the inability to regenerate the pristine correct anatomy system. The aim of this study is to assess the potential use of mesenchymal stem cells (MSCs in the regeneration of original periodontal structure. This study is an experimental phase 1 approved by the Italian Institute of Health on a limited number of patients; main objective will be to assess the biocompatibility and toxicity in vivo of differentiated mesenchymal stem cells into osteoblast sense, supported by biomimetic collagen scaffolds in patients with severe periodontal disease. The protocol describes transplantation of mesenchymal stem cells derived from samples of percutaneous bone marrow aspirate. The bone marrow cells are manipulated ex vivo to isolate mesenchymal stem cell

  2. Experimental findings on thermal use of residues and biofuels in circulating fluidized bed combustion systems; Experimentelle Ergebnisse zur thermischen Nutzung von Rest- und Biobrennstoffen in zirkulierenden Wirbelschichtfeuerungen

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, W.; Brunne, T.; Girndt, H. [Technische Univ. Dresden (Germany); Albrecht, J. [Lurgi Lentjes Babcock, Frankfurt am Main (Germany); Youssef, M. [Minia Univ. (Egypt)

    1996-12-31

    The energy Engineering Institute of Dresden Technical University investigated the combustion and emission characteristics of a number of combustion systems, including a circulating fluidized bed system with a capacity of 0.3 MW{sub th}. Egypt`s sugar cane industry produces large volumes of bagasse. The conbustion and emission characteristics of this biofuel in a circulating fludized bed combustion systems were investigated in a joint research project of the University of Minia and Dresden Technical University. (orig.) [Deutsch] Am Institut fuer Energietechnik der TU Dresden wird das Verbrennungs- und Emissionsverhalten verschiedenster Brennstoffe in unterschiedlichen Feuerungssystemen untersucht. Neben anderen Pilotanlagen steht eine zirkulierende Wirbelschichtfeuerung (ZWFS) mit einer Leistung von 0.3 MW{sub th} zur Verfuegung. In der Zuckerrohrindustrie Aegyptens fallen grosse Mengen von Bagasse an. In einer gemeinsamen Forschungsarbeit zwischen der Universitaet Minia und der TU Dresden sollte das Verbrennungs- und Emissionsverhalten dieses Biobrennstoffes in einer ZWSF untersucht werden. (orig)

  3. Biomass gasification in fixed bed type down draft: theoretical and experimental aspects; Gasificacao de biomassa em leito fixo tipo concorrente: aspectos teoricos e experimentais

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Juan Daniel; Andrade, Rubenildo Vieira; Lora, Electo Eduardo Silva [Universidade Federal de Itajuba (UNIFEI), MG (Brazil). Inst. de Engenharia Mecanica. Nucleo de Excelencia em Geracao Termeletrica e Distribuida

    2008-07-01

    Actually are recognizing the advantages of biomass in reducing dependence on fossil fuels and significant reduction in emissions of greenhouse effect gases such as Co2. Also are known the different conversion of biomass routes for their use or exploitation, such as thermochemical process (gasification, pyrolysis and combustion), the biological process (fermentation and transesterification) and the physical process (densification, reducing grain and mechanical pressing). In this sense, the gasification is regarded as the most promising mechanism to obtain a homogeneous gaseous fuel with sufficient quality in the small scale distributed generation. This work presents some aspects of biomass gasification in fixed bed, as well as some preliminary results in the evaluation and operation of fixed bed down draft gasifier with double stage air supply of the NEST, identifying the adequate air supply quantity (equivalence ratio in the range of 0,35 to 0,45) for obtaining a fuel gas with lower heating value around 4 MJ/N m3. (author)

  4. Experimental investigations of solid-state-fermentation in gas/solid fluidized bed. Experimentelle Untersuchungen zur Solid-State-Fermentation in der Gas/Feststoff-Wirbelschicht

    Energy Technology Data Exchange (ETDEWEB)

    Behns, W. (FZB Biotechnik GmbH, Berlin (Germany)); Ebenau, B. (FZB Biotechnik GmbH, Berlin (Germany)); Friedrich, K. (Technische Univ. Magdeburg (Germany). Inst. fuer Apparate- und Umwelttechnik); Grau, W. (Technische Univ. Magdeburg (Germany). Inst. fuer Apparate- und Umwelttechnik); Haida, H. (Technische Univ. Magdeburg (Germany). Inst. fuer Apparate- und Umwelttechnik); Kuenne, H.J. (Magdeburger Energie- und Umwelttechnik GmbH, Magdeburg (Germany)); Lakowitz, R. (Technische Univ. Magdeburg (Germany). Inst. fuer Apparate- und Umwelttechnik)

    1993-01-01

    Solid-state fermentations in gas-fluidized beds promise on principle advantages in comparison with the liquid-phase-culture. Problems concerning the technical processing follow from milieu conditions and heat and mass transfer. The set of problems was investigated in five series of experiments on different yeasts. To obtain optimal conditions for biomass growth and/or product formation controlling of air and solid moisture content and avoiding of agglomeration have to be governed. (orig.)

  5. Osteointegración del aloinjerto crioconservado asociado a plasma enriquecido en plaquetas, en defectos óseos infectados. Estudio experimental. [Osseointegration of cryopreserved allograft associated with platelet-rich plasma, in infected bone defects. Experimental study.

    Directory of Open Access Journals (Sweden)

    Pablo Alexis Bruno

    2013-08-01

    Full Text Available Introducción El objetivo de este trabajo experimental es determinar si el agregado de plasma rico en plaquetas influye en la osteointegración del aloinjerto crioconservado con antibióticos, en fracturas infectadas, con pérdida ósea, en huesos largos de conejos. Material y métodos Se evaluaron cuatro grupos de 7 conejos cada uno, a los cuales se les generó una fractura infectada del fémur derecho. En los cuatro grupos, se colocó aloinjerto molido con antibiótico local, en el grupo II y en el grupo IV, se agregó también plasma rico en plaquetas. Se sacrificó a los grupos I y II, a los 30 días, y a los grupos III y IV, a los 90 días. Se realizó una evaluación histológica y tomográfica. Resultados Nueve conejos murieron en el período de estudio. No hubo diferencias estadísticamente significativas entre los grupos evaluados. En el grupo IV, con plasma rico en plaquetas, se observó neoformación ósea en tres de las cuatro muestras; se advirtieron sectores de acoplamiento entre el tejido receptor y el injertado, con consolidación en las imágenes tomográficas. Conclusiones En este trabajo, hubo correlación entre los resultados histológicos y tomográficos. Pese a que no se hallaron diferencias estadísticamente significativas, el agregado de plasma rico en plaquetas, además de estimular la generación de nuevos tejidos, disminuyó la reabsorción del tejido injertado al análisis anatomopatológico, y mostró mayor neoformación ósea y consolidación en el grupo IV (75% tratado con plasma rico en plaque- tas que en el grupo III (25% al que no se asoció plasma rico en plaquetas al aloinjerto óseo.

  6. Estudio teórico-experimental de los mecanismos de adaptación ante Campos Luminosos pequeños en diferentes localizaciones retinianas

    OpenAIRE

    Hernán Gloriani, Alejandro

    2016-01-01

    La percepción visual es un proceso muy complejo en el que intervienen diversas estructuras y mecanismos. Su estudio puede ser abordado desde diferentes perspectivas debido principalmente al hecho de que combina elementos de campos tan diversos como la física, la fisiología, la psicología y la psicofísica. El mundo que nos rodea se nos presenta a través de estímulos, información que nuestro cerebro decodifica y procesa. Para optimizar la transmisión de la información visual el sistema nerv...

  7. Sistema de análisis de patrones implementado en FPGAs para el estudio experimental de los ligamentos en la articulación

    OpenAIRE

    J.J. Raygoza Panduro; Susana Ortega Cisneros; Nuria Bonsfills; Ángel Núñez; E Gómez Barrena

    2009-01-01

    La lesión del ligamento cruzado anterior (LCA) ha sido una de las patologías más estudiadas desde diferentes puntos de vista. Se ha experimentado con las variables, que de forma directa o indirecta, definen el concepto de inestabilidad producida por esta lesión. Debido a la dificultad que implica la realización de mediciones de la tensión y deformación de estas estructuras se han propuesto una amplia gama de metodologías de medición de este fenómeno. El interés por el estudio tensional de las...

  8. Bed rest during pregnancy

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000581.htm Bed rest during pregnancy To use the sharing features on ... your daily activities. Why Do I Need Bed Rest? Bed rest used to be recommended routinely for ...

  9. 复合肥喷涂包裹尿素转鼓流化床试验装置的设计%Design of Experimental Unit of Rotary Drum Fluidization Bed for Spray Coating Urea with Compound Fertilizer

    Institute of Scientific and Technical Information of China (English)

    石学勇; 王金铭; 王金刚

    2014-01-01

    Because rotary drum fluidization bed technology has advantages of low power consumption, good spraying effect, high product quality, compaction of equipment, great production capacity, and low investment, therefore, rotary drum fluidization bed process is chosen for spray coating urea with compound fertilizer experiment.The process calculation of rotary drum fluidization bed used in experiment is introduced, through calculating of heat balance and selection of major equipments, such as fluidization fan, rotary drum for coating, and spray nozzle, etc., the design of experimental unit is completed.%转鼓流化床技术具有动力消耗低、喷涂效果好、产品质量高、设备紧凑、生产能力大、投资低等诸多优势,为此,复合肥喷涂包裹尿素试验选定转鼓流化床工艺。介绍了试验所用转鼓流化床的工艺计算,通过热量衡算和对流化风机、包裹滚筒、喷头等主要设备的选型,完成了试验装置的设计。

  10. Learning in artistic gymnastics. An experimental study with children analysing some variables in that process Aprendizaje en gimnasia artística. Un estudio experimental con niños que analiza ciertas variables del proceso

    Directory of Open Access Journals (Sweden)

    J. López

    2010-09-01

    : Gymnastics, teaching methods, Children training, Feedback, Aids

    En la actualidad el entrenamiento de la técnica deportiva ha motivado la creación de nuevos planteamientos con el fin de obtener máximos resultados. En la práctica son muchos los métodos de enseñanza empleados, pero la mayor parte de las publicaciones relativas al aprendizaje motor y al entrenamiento deportivo hablan del método global o total y del método parcial o analítico, cobrando ambos un interés especial dentro de la Gimnasia Artística.

    Sobre la efectividad de estas estrategias las opiniones son diferentes. Sin embargo, Carrasco (1977 propone los Mini-circuitos como la estrategia más eficaz para el aprendizaje de habilidades gimnásticas. Motivados por dar una solución práctica a esta cuestión del aprendizaje global y fraccionado hemos realizado un estudio experimental de grupos con niños de escuelas deportivas con un rango de edad de 9 a 11 años. El objetivo era delimitar la eficacia diferencial de tres tipos de entrenamiento ( Analítico, "Mini-circuito" y Mixto sobre el aprendizaje y retención en una habilidad gimnástica. Interesados no sólo en el rendimiento final sino también en todo el proceso de enseñanza, estudiamos las siguientes variables: Tiempo de Actividad Motriz,Tiempo de Espera, Nº de Movimientos Globales, Nº de Feedbacks Emitidos por el Profesor y Nº Total de Asistencias.

    Los resultados del estudio muestran la eficacia del Minicircuito sobre el resto de las estrategias. Las variables del proceso más afectadas han sido, los tipos de Asistencias prestadas así como los tipos de Feedbacks. Desde el punto de vista de la enseñanza, es un dato importante a considerar, ya que su aplicación puede resultar de gran utilidad en la etapa escolar.

    PALABRAS CLAVE: Gimnasia, Metodología, Entrenamiento con niños, Feedback, Ayudas.

  11. Estudio experimental sobre la regeneración ósea mandibular de la rata con diferentes biomateriales Experimental study in rats of mandibular bone regeneration with different biomaterials

    Directory of Open Access Journals (Sweden)

    B. Peral Cagigal

    2008-10-01

    Full Text Available Objetivo. Los defectos óseos mandibulares resultantes de infecciones, traumatismos o resecciones oncológicas, van a producir severos problemas funcionales y/o estéticos, que van a precisar de un tratamiento complejo. Durante los últimos años, las aportaciones al terreno de la reconstrucción ósea se han debatido entre métodos tan dispares como la distracción ósea o la utilización de colgajos libres microvascularizados, pasando por un sin fin de biomateriales. El objetivo de este estudio fue comparar la formación de hueso nuevo tras la aplicación de una membrana reabsorbible y dos tipos de sustitutivos óseos. Material y método. Se utilizaron 24 ratas adultas macho tipo Wistar, en las que se crearon defectos circulares de 4 mm de diámetro en ambos lados de la mandíbula. Se formaron 4 grupos, un grupo control y 3 grupos experimentales. Los animales fueron sacrificados a las 3 y 6 semanas de la cirugía, realizándose un análisis radiológico e histológico. Resultados. Los defectos control no mostraron formación ósea, apareciendo una reparación por tejido fibroso. La membrana de hueso utilizada de forma aislada, actuó como una barrera eficaz excluyendo los tejidos no osteogénicos, pero no se produjo reparación total del defecto en ningún caso. El grupo de Colloss® y membrana, mostró una regeneración ósea completa del defecto a las 6 semanas. El grupo de NovaBone® y membrana, no mostró formación ósea, apareciendo las partículas del biomaterial ocupando el defecto. Conclusiones. La regeneración ósea fue significativamente mayor en los defectos rellenos con Colloss® y cubiertos con la membrana de Lambone®, comparado con los otros grupos experimentales.Objective. Mandibular bone defects can occur as a result of trauma, neoplasm, or infectious conditions. Such conditions often are associated with severe funtional and esthetic problems. Corrective treatment often is complicated by limitations in tissue adaptation. The

  12. Estudio preliminar experimental en ratas: uso de plasma rico en plaquetas en el tratamiento de lesiones agudas de nervios periféricos

    Directory of Open Access Journals (Sweden)

    Natalia Sorrenti-Pírez

    Full Text Available Antecedentes y Objetivos. Si consideramos la importancia social y laboral que han adquirido las lesiones de los nervios periféricos por las graves y permanentes secuelas motoras, sensitivas y vegetativas a que dan lugar, cualquier esfuerzo terapéutico para mejorar los resultados de la reparación nerviosa representa un paso positivo dentro del abordaje general de esta afección. A pesar de realizar una sutura técnicamente perfecta, nunca se logra repoblar el segmento distal con la misma cantidad de axones. Esto hace que se busquen alternativas para potenciar la regeneración nerviosa. Dentro de las terapias emergentes, la utilización de plasma rico en plaquetas (PRP tiene un efecto beneficioso en la reparación nerviosa. Hasta este momento los estudios se han centrado en la utilización del PRP dentro de injertos o tutores interpuestos entre los cabos y no se ha prestado atención a la aplicación del mismo en la sutura directa. Material y Métodos. Estudiamos 8 ratas Wistar a las que se les seccionaron ambos nervios ciáticos; a una de las suturas se le aplicó PRP y el otro nervio suturado se tomó como caso control. En una segunda etapa realizamos la biopsia de ambos nervios a diferentes tiempos y fijamos con un fluoróforo lipofílico que tiñe las fibras regeneradas. Tomamos 2 grupos: a los 40 días y a los 60 días. Calculamos el índice de función del nervio ciático. Resultados. Los nervios seccionados y tratados con PRP presentaron un adelanto en la recuperación de la función nerviosa medida por pruebas funcionales; confirmamos anatómicamente mediante el estudio histológico del nervio. Conclusiones. Los resultados obtenidos en el estudio indican una estimulación del proceso fisiológico de reparación nerviosa usando PRP.

  13. Estudio experimental sobre la recepción de información ante dos tipos de códigos: verbal y verboicónico

    Directory of Open Access Journals (Sweden)

    Bernardino SALINAS FERNÁNDEZ

    2009-11-01

    Full Text Available El lenguaje verboicónico puede ser definido como aquel tipo de lenguaje en el que se integran, de forma más o menos coherente, signos verbales y signos icónicos en una secuencia discursiva con el fin de significar determinado mensaje. O, desde una perspectiva semiótica, aquel sistema donde tienen lugar dos modos diferentes de producción de funciones semióticas. El objetivo fundamental del presente estudio ha sido el intento de comparar las diferencias, fundamentalmente cuantitativas, en la recepción de un mensaje por parte del sujeto, ante dos modos diferentes de producción de funciones semióticas, verbal y verboicónica.

  14. Estudio teórico y experimental de un prototipo de invernadero basado en una estructura resistente plana, ligera, elástica y altamente deformable

    Directory of Open Access Journals (Sweden)

    de la Cruz, José L.

    1996-08-01

    Full Text Available El creciente empleo de estructuras ligeras, tanto en invernaderos en países de clima templado, como, más recientemente, en arquitectura textil para instalaciones de recreo, justifica el desarrollo de este tipo de estructuras. El objeto del presente trabajo es contribuir con un nuevo modelo de estructura de cubierta ligera y flexible, aportando un modelo teórico que se presenta, tras su validación con datos experimentales obtenidos sobre un prototipo, como una metodología adecuada para el cálculo de dicha estructura. La obtención de conclusiones sobre el comportamiento estructural y el estudio de costes realizado sobre el prototipo permiten, dada su viabilidad técnica y económica, proponerlo como una solución alternativa a los invernaderos tradicionales.

    El creciente empleo de estructuras ligeras, tanto en invernaderos en países de clima templado, como, más recientemente, en arquitectura textil para instalaciones de recreo, justifica el desarrollo de este tipo de estructuras. El objeto del presente trabajo es contribuir con un nuevo modelo de estructura de cubierta ligera y flexible, aportando un modelo teórico que se presenta, tras su validación con datos experimentales obtenidos sobre un prototipo, como una metodología adecuada para el cálculo de dicha estructura. La obtención de conclusiones sobre el comportamiento estructural y el estudio de costes realizado sobre el prototipo permiten, dada su viabilidad técnica y económica, proponerlo como una solución alternativa a los invernaderos tradicionales.

  15. Incipient motion of gravel and coal beds

    Indian Academy of Sciences (India)

    Subhasish Dey; Uddaraju V Raju

    2002-10-01

    An experimental study on incipient motion of gravel and coal beds under unidirectional steady-uniform flow is presented. Experiments were carried out in a flume with various sizes of gravel and coal samples. The critical bed shear stresses for the experimental runs determined using side-wall correction show considerable disagreement with the standard curves. The characteristic parameters affecting the incipient motion of particles in rough-turbulent regime, identified based on physical reasoning and dimensional analysis, are the Shields parameter, particle Froude number, non-dimensional particle diameter and non-dimensional flow depth. Equations of critical bed shear stress for the initial movement of gravel and coal beds were obtained using experimental data. The method of application of critical bed shear stress equations is also mentioned.

  16. 强内热源球床通道单相对流换热特性实验研究%Experimental Study on Single-Phase Convection Heat Transfer Characteristics of Pebble Bed Channels With Internal Heat Generation

    Institute of Scientific and Technical Information of China (English)

    孟现珂; 孙中宁; 周平; 徐广展

    2012-01-01

    The water-cooled pebble bed reactor core is the porous channels stacked with spherical fuel elements, having evident effect on enhancing heat transfer. Owing to the variability and randomness characteristics of it's interstice, pebble bed channels have a very complex heat transfer situation and have little correlative research. In order to research the heat transfer characters of pebble bed channels with internal heat source, electromagnetic induction heating method was adopted for overall heating the pebble bed which was composed of 8 mm diameter steel balls, and the internal heat transfer characteristics were researched. By comparing and analyzing the experimental data, the rule of power distribution and heat transfer coefficient with heat flux density, inlet temperature and working fluid' s Re were got. According to the experimental data fitting, the dimensionless average heat transfer coefficient correlation criteria was got. The fitting results are good agreement with the experimental results within difference.%球床水冷反应堆的堆芯为球形燃料元件堆积成的多孔通道,具有显著的强化换热作用.球床通道内的孔隙因具有多变性、随机性的特点,换热情况非常复杂,相关研究较少.为了研究含内热源球床通道内的换热特性,本文用直径为8 mm碳钢球堆积形成球床,以蒸馏水为工质,采用电磁感应加热方式对球床进行整体加热,研究球床通道内部的换热特性.通过对实验数据进行分析,得到了球床通道内部的功率分布和换热系数随热流密度、工质Re的变化规律,根据实验数据拟合得到了球床通道内平均换热系数的无量纲准则关联式,拟合结果与实验结果的相对偏差在12%以内,符合良好.

  17. Bed dynamics of gas-solid fluidized bed with rod promoter

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The dynamic characteristics of a gas-solid fluidized bed with different rod promoters have been investigated in terms of bed expansion and fluctuation, minimum fluidization velocity and distributor-to-bed pressure drop ratio at minimum fluidization velocity. Experimentation based on statistical design has been carried out and model equations using factorial design of experiments have been developed for the above mentioned quantities for a promoted gas-solid fluidized bed. The model equations have been tested with additional experimental data. The system variables include four types of rod promoters of varying blockage volume, bed particles of four sizes and four initial static bed heights. A comparison between the predicted values of the output variables using the proposed model equation with their corresponding experimental ones shows fairly good agreement.

  18. Using an experimental model for the study of therapeutic touch Uso de un modelo experimental para estudio sobre el toque terapéutico Utilização de um modelo experimental para estudo sobre o toque terapêutico

    Directory of Open Access Journals (Sweden)

    Daniella Soares dos Santos

    2013-02-01

    Full Text Available OBJECTIVE: to verify whether the Paw Edema Model can be used in investigations about the effects of Therapeutic Touch on inflammation by measuring the variables pain, edema and neutrophil migration. METHOD: this is a pilot and experimental study, involving ten male mice of the same genetic strain and divided into experimental and control group, submitted to the chemical induction of local inflammation in the right back paw. The experimental group received a daily administration of Therapeutic Touch for 15 minutes during three days. RESULTS: the data showed statistically significant differences in the nociceptive threshold and in the paw circumference of the animals from the experimental group on the second day of the experiment. CONCLUSION: the experiment model involving animals can contribute to study the effects of Therapeutic Touch on inflammation, and adjustments are suggested in the treatment duration, number of sessions and experiment duration.OBJETIVO: verificar si el Modelo de Edema de Pata puede ser utilizado en las investigaciones acerca de los efectos del Toque Terapéutico sobre la inflamación, mensurándose las variables dolor, edema y migración de neutrófilos. MÉTODO: se trata de un estudio piloto, experimental, con 10 ratones machos del mismo linaje genético, divididos en grupo experimental y control, sometidos a inducción química de inflamación local en la pata derecha trasera. O grupo experimental recibió una aplicación diaria de Toque Terapéutico con duración de quince minutos, por tres días. RESULTADOS: Los datos evidenciaron diferencias estadísticamente significativas en el umbral de nocicepción y circunferencia de las patas de los animales del grupo experimental durante el segundo día del experimento. CONCLUSIÓN: El modelo de experimento con animal puede contribuir al estudio de los efectos del Toque Terapéutico sobre la inflamación: se sugiere ajuste en el tiempo de exposición, número de sesiones y

  19. Contribución al estudio experimental del cancer III. Alteraciones de la corteza suprarrenal en la Carcinogenesis Química.

    Directory of Open Access Journals (Sweden)

    Oscar Miro-Quesada C

    1948-12-01

    Full Text Available 1.- Se hace un estudio crítico histo-químico funcional de la corteza suprarrenal en ratones homozigotes C3H (Strong sometidos a la cancerización química con 20-Metilcolantreno. 2.- Se describe un nuevo tipo de reacción funcional de dicha glándula bajo las condiciones experimentales empleadas, sugiriéndose la denominación de "atrofia-hiperactiva", en contraste con las alteraciones histo-químico funcionales de la corteza suprarrenal descritas por varios autores en animales portadores de injertos neoplásicos, las que corresponden al tipo de reacción funcional de la glándula caracterizado por "hipertrofia-hiperactiva". 3.- Los resultados obtenidos sugieren la intervención del sistema endocrino, via la corteza suprarrenal, durante el proceso de carcinogenesis química en el ratón homozigote de raza C3H (Strong.

  20. Catalizadores de Pt / y-Al2O3 con distribución no uniforme: estudio teórico y experimental

    Directory of Open Access Journals (Sweden)

    Jacqueline Ardila

    2011-01-01

    Full Text Available Una serie de catalizadores de Pt / y-Al203  se prepararon por impregnación simultánea y secuencial por vía húmeda, con ácido hexacloroplatínico como precursor catalítico y ácido cítrico como competidor. Las concentraciones de los ácidos hexacloroplatínico y cítrico se mantuvieron constantes durante la preparación de los catalizadores y el tiempo de impregnación se varió entre 2, 6 y 12 horas. Un estudio de microscopía electrónica se realizó para el grupo de catalizadores, el cual determinó el tipo de perfil y distribución, y algunas diferencias entre los dos tipos de impregnación. Para la impregnación simultánea se planteo un modelo matemático que predice los perfiles de concentración de Pt dentro del soporte. Se consideró un mecanismo de adsorción competitiva del tipo Langmuir entre el ácido hexacloroplatínico y el ácido cítrico. La distribución y el tipo de peñtl encontrados por el modelo concuerdan con los resultados obtenidos experimentalmente.

  1. Reacciones hormonales e inmunológicas agudas en situaciones de estrés. Estudio experimental sobre el papel moderador de la experiencia de control

    Directory of Open Access Journals (Sweden)

    Viviola Gómez

    2001-01-01

    Full Text Available El objetivo central de este estudio fue determinar experimentalmente las diferencias en los patrones de respuesta hormonal e inmunológica, como también en los estados emocionales de los participantes, al ser confrontados con situaciones de exigencia en condiciones de evidente control y de no-control. Uno de los grupos recibió feedback positivo durante la realización de la tarea ("control" y el segundo grupo recibió feedback negativo en iguales condiciones ("no control". Al confrontar las condiciones experimentales "control" y "sin control", únicamente los datos en las variables psicológicas mostraron diferencias significativas. Sin embargo, la experiencia de control correlacionó negativamente con varios de los parámetros inmunológicos con tendencia a aumentar bajo condiciones de exigencia y positivamente con aquellos que mostraron disminución bajo las mismas condiciones. Estos datos nos indican que en la medida en que disminuyó la percepción de control en la tarea, hubo incrementos y decrementos de mayor magnitud en algunas de las variables inmunológicas.

  2. Classifying bed inclination using pressure images.

    Science.gov (United States)

    Baran Pouyan, M; Ostadabbas, S; Nourani, M; Pompeo, M

    2014-01-01

    Pressure ulcer is one of the most prevalent problems for bed-bound patients in hospitals and nursing homes. Pressure ulcers are painful for patients and costly for healthcare systems. Accurate in-bed posture analysis can significantly help in preventing pressure ulcers. Specifically, bed inclination (back angle) is a factor contributing to pressure ulcer development. In this paper, an efficient methodology is proposed to classify bed inclination. Our approach uses pressure values collected from a commercial pressure mat system. Then, by applying a number of image processing and machine learning techniques, the approximate degree of bed is estimated and classified. The proposed algorithm was tested on 15 subjects with various sizes and weights. The experimental results indicate that our method predicts bed inclination in three classes with 80.3% average accuracy.

  3. Estudio experimental de la formación de porosidad por ingestión de aire en la etapa lenta de los procesos de fundición por inyección

    OpenAIRE

    Faura Mateu, Félix; Zamora Pedreño, Rosendo; Estrems Amestoy, Manuel; Hernández Ortega, Juan José; Sánchez Reinoso, Horacio Tomás; Sanes Molina, José

    2010-01-01

    El proyecto de investigación titulado "Estudio experimental de la formación de porosidad por ingestión de aire en la etapa lenta de los procesos de fundición por inyección" que corresponde a la referencia DPI2001-1390-C02-01 está centrado en el análisis de la etapa lenta de las operaciones de fundición por inyección a alta presión mediante técnicas experimentales. Mediante este proyecto de investigación se pretende incrementar el nivel de conocimientos de que se dispone acerca de esta etapa, ...

  4. Necesidades de formación de los docentes de bachillerato. Estudio realizado en la Unidad Educativa Experimental Liceo Policial del cantón Quito de la provincia de Pichincha, período lectivo 2012-2013

    OpenAIRE

    Goyes Silva, Freddy Omar

    2014-01-01

    El presente trabajo es un estudio sobre el Diagnóstico de las necesidades de formación de los docentes de bachillerato . En esta tesis se realizó una encuesta, donde se contó con la participación de 20 profesores de bachillerato del Colegio Experimental Liceo Policial de la ciudad de Quito. Se efectuó una investigación de campo utilizando el método analítico, hermenéutico a través de las técnicas de encuestas y lecturas en la cual se determinó las necesidades de formación que se d...

  5. Estudio experimental sobre la utilización de células madre humanas en la terapia de los defectos periodontales: resultados preliminares Experimental study on the use of human stem cell therapy in periodontal defects: Preliminary results

    OpenAIRE

    2011-01-01

    La destrucción del ligamento periodontal y de la cresta alveolar causada por la enfermedad periodontal, constituye la principal causa de pérdida dentaria en pacientes adultos. Resulta difícil que la terapia en la enfermedad periodontal avanzada lleve a una restitutio ad integrum de la estructura que se ha perdido por la imposibilidad de regenerar la correcta anatomía del sistema perdido. Este estudio tiene como objetivo evaluar el potencial y la estabilidad de la utilización de células madre ...

  6. Estudio experimental de la osteosustitución con biomateriales cerámicos formulados como cementos óseos Experimental study of the bone substitution with ceramic biomaterials formulated as bone cements

    OpenAIRE

    Sanzana, E. S.; Ginebra, M.P.; P A Torres; J A Planell; Navarro, M. E.

    2007-01-01

    Los biomateriales cerámicos presentan interesantes propiedades biológicas, por lo que pueden ser utilizados en la sustitución ósea. En este estudio fueron comparados dos cementos óseos de fosfato de calcio con el autoinjerto óseo esponjoso. Se realizó un defecto cavitario de 6 mm en la metáfisis femoral distal derecha de 36 conejos machos Oryctolagus cuniculi. Los animales fueron divididos en 3 grupos de 12 conejos, que recibieron como implantes cemento de fosfato a tricálcico (TPC), cemento ...

  7. Estudio numérico y experimental de los flujos atmosféricos y dispersión de contaminantes en entornos urbanos = Numerical and experimental study of atmospheric flows and pollutant dispersion in urban environment

    OpenAIRE

    Santiago del Río, José Luis

    2006-01-01

    La contaminación atmosférica en entornos urbanos se ha convertido en los últimos años en uno de los problemas medio ambientales más importantes. Por este motivo, tanto las autoridades como la comunidad científica han prestado una atención especial al estudio de la calidad de aire dentro de las ciudades. Un ejemplo es el informe "Air pollution at street levels in European cities" (2006) realizado por la Agencia Europea de Medio Ambiente (European Environment Agency) donde se analiza la calidad...

  8. Capacidad condrogénica de injertos libres de periostio en la reparación de defectos del cartílago articular: estudio experimental en conejos

    OpenAIRE

    1996-01-01

    Ante la incapacidad de reparación de las lesiones del cartílago articular, hemos diseñado un modelo experimental, consistente en la realización de una úlcera condral de 8 mm, en la superficie articular de la rótula, en 48 conejos distribuidos en 2 series. Mientras en la serie control (24 conejos) dicha úlcera se dejó a evolución espontánea, en la experimental (24 conejos) fue cubierta con plastia libre de periostio tibial para poder investigar la posibilidad de regeneración del...

  9. The influence of fibrous bed bulk density on the bed properties

    Directory of Open Access Journals (Sweden)

    Šećerov-Sokolović Radmila M.

    2003-01-01

    Full Text Available The mean properties of seven different fibrous materials and the properties of their different bed bulk densities were investigated. The morphology of the surface, size and geometry were measured by optical microscopy. The bed porosity was measured by the weighing method. The experimental bed permeability, in a high range of bulk density, was calculated from the values of the sanitary water pressure drop at a constant temperature of 15°C, since the data followed Darcy's law. The Reynolds number for a fibrous bed was calculated using a relation from the literature. The Reynolds number was less than 1 for all ranges of fluid velocity. Three empirical relations for fibrous bed permeability were used and compared with the experimental data. It was determined that the empirical data depended on the fiber diameter and fraction of solid in the bed. The relative error linearly increased with increasing fiber diameter.

  10. The effect of vibration on bed voidage behaviors in fluidized beds with large particles

    Energy Technology Data Exchange (ETDEWEB)

    Jin, H.; Zhang, J.; Zhang, B.

    2007-07-01

    The effects of vibration parameters, operating conditions and material properties on bed voidage were investigated using an optical fiber probe approach in a vibrating fluidized bed with a diameter of 148 mm. Variables studied included frequency (0-282 s{sup -1}), amplitude (0 mm-1 mm), bed height (0.1 m-0.4 m) as well as four kinds of particles (belonging to Geldart's B and D groups). The axial and radial voidage distribution with vibration is compared with that without vibration, which shows vibration can aid in the fluidization behaviors of particles. For a larger vibration amplitude, the vibration seriously affects bed voidage. The vibration energy can damp out for particle layers with increasing the bed height. According to analysis of experimental data, an empirical correlation for predicting bed voidage, giving good agreement with the experimental data and a deviation within {+-}15%, was proposed. 20 refs., 8 figs., 2 tabs.

  11. The effect of vibration on bed voidage behaviors in fluidized beds with large particles

    Directory of Open Access Journals (Sweden)

    H. Jin

    2007-09-01

    Full Text Available The effects of vibration parameters, operating conditions and material properties on bed voidage were investigated using an optical fiber probe approach in a vibrating fluidized bed with a diameter of 148 mm. Variables studied included frequency (0-282 s-1, amplitude (0 mm-1 mm, bed height (0.1 m-0.4 m as well as four kinds of particles (belonging to Geldart's B and D groups. The axial and radial voidage distribution with vibration is compared with that without vibration, which shows vibration can aid in the fluidization behaviors of particles. For a larger vibration amplitude, the vibration seriously affects bed voidage. The vibration energy can damp out for particle layers with increasing the bed height. According to analysis of experimental data, an empirical correlation for predicting bed voidage, giving good agreement with the experimental data and a deviation within ±15%, was proposed.

  12. 飞灰流化床燃烧脱碳的试验研究%Experimental Study of Fly Ash Decarbonization on a Circulating Fluidized Bed Combustor

    Institute of Scientific and Technical Information of China (English)

    梅琳; 卢啸风; 王泉海; 潘智; 杨宇; 洪勇; 方纯全; 郭宏; 阳向东

    2014-01-01

    飞灰回燃脱碳效率较低,导致回燃后飞灰仍不能满足综合利用的要求。文中基于飞灰的冷态流化特性,在自行设计的纯然飞灰的热态试验台上进行了燃烧脱碳试验。试验结果表明:CFB 飞灰能够在流化床内连续稳定燃烧,维持炉内燃烧的最小截面热负荷约为0.4MW/m2,对应的临界飞灰含碳量为18%。密相区温度和运行床压对飞灰脱碳均有一定的影响。飞灰燃烧后在底渣的增重份额很小,最大不超过15%。试验系统的最大脱碳效率约为75%,远远高于飞灰回燃的脱碳效率。%ABSTRACT:Because of the huge difference between original boiler operating conditions and fly ash ideal combustion state, the decarbonization effect is disappointed. Consequently, fly ash decarbonization experiments were carried out on a lab-scale CFB combustor designed base on fluidization properties of fly ash and the decarbonization characteristics were presented. Results show that fly ash requires a minimum sectional thermal load of 0.4MW/m2 for continuous and stable combustion in test combustor, the corresponding critical carbon content in the fly ash is 18%. The carbon content in the fly ash is clearly affected by the dense-bed temperature and bed pressure drop during the combustion process. In addition, the fly ash mass fraction in bottom ash does not exceed 15%. The maximum decarbonization efficiency of the test CFB combustor is approximately 75%, which is much higher than that of FARC.

  13. Experimental Study on Gas-Solid Mass Transfer in Circulating Fluidized Beds%循环流化床气固传质实验研究

    Institute of Scientific and Technical Information of China (English)

    王琳娜; 张苓; 靳东杰; 李静海

    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 3.0 m in height and 72 mm 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 conditions, 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 dilute 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.

  14. Critical conditions of bed sediment entrainment due to debris flow

    Directory of Open Access Journals (Sweden)

    M. Papa

    2004-01-01

    Full Text Available The present study describes entrainment characteristics of bed material into debris flow, based on flume tests, numerical and dimensional analyses. Flume tests are conducted to investigate influences of bed sediment size on erosion rate by supplying debris flows having unsaturated sediment concentration over erodible beds. Experimental results show that the erosion rate decreases monotonically with increase of sediment size, although erosion rate changes with sediment concentration of debris flow body. In order to evaluate critical condition of bed sediment entrainment, a length scale which measures an effective bed shear stress is introduced. The effective bed shear stress is defined as total shear stress minus yield stress on the bed surface. The results show that critical entrainment conditions can be evaluated well in terms of Shields curve using the effective bed shear stress instead of a usual bed shear stress.

  15. Estudio experimental de la osteosustitución con biomateriales cerámicos formulados como cementos óseos Experimental study of the bone substitution with ceramic biomaterials formulated as bone cements

    Directory of Open Access Journals (Sweden)

    E S Sanzana

    2007-01-01

    Full Text Available Los biomateriales cerámicos presentan interesantes propiedades biológicas, por lo que pueden ser utilizados en la sustitución ósea. En este estudio fueron comparados dos cementos óseos de fosfato de calcio con el autoinjerto óseo esponjoso. Se realizó un defecto cavitario de 6 mm en la metáfisis femoral distal derecha de 36 conejos machos Oryctolagus cuniculi. Los animales fueron divididos en 3 grupos de 12 conejos, que recibieron como implantes cemento de fosfato a tricálcico (TPC, cemento de fosfato monocálcico (MPC y autoinjerto óseo (CON. Los estudios radiológico e histológico han mostrado una correcta sustitución de ambos biomateriales por hueso neoformado. El estudio histomorfométrico ha revelado que la neoformación ósea obtenida con los 2 cementos, tanto a las 4 como las 12 semanas, es equivalente a la generada por el injerto óseo. No se han encontrado diferencias significativas en la reabsorción de los materiales. Finalmente, este trabajo ha concluido que los cementos óseos de fosfato de calcio son materiales osteoconductivos, osteotransductivos y biocompatibles que se comportan como sustitutivos óseos.Ceramic biomaterials have interesting biological properties that can be used in bone substitution. In this study two calcium phosphate bone cements were compared to cancellous bone autograft. A bone cavitary defect of 6 mm in diameter was carried out in the right distal femoral methaphyses of 36 male rabbits Oryctolagus cuniculi. The animals were divided into 3 groups of 12 rabbits receiving a tricalcium phosphate cement (TPC, monocalcium phosphate cement (MPC and autologous bone (CON as implants. The radiological and histological studies showed a correct substitution of both biomaterials with new bone. The histomorphometric study revealed that the bone neoformation obtained with the two cements at 4 and 12 weeks is equivalent to the bone generated by the bone graft. There were no significant differences in the

  16. Nonlinear dynamical characteristics of bed load motion

    Institute of Scientific and Technical Information of China (English)

    BAI; Yuchuan; XU; Haijue; XU; Dong

    2006-01-01

    Bed forms of various kinds that evolve naturally on the bottom of sandy coasts and rivers are a result of the kinematics of bed load transport. Based on the group motion of particles in the bed load within the bottom layer, a study on the nonlinear dynamics of bed load transport is presented in this paper. It is found that some development stages, such as the initiation, the equilibrium sediment transport, and the transition from a smooth bed to sand dunes, can be accounted for by different states in the nonlinear system of the bed load transport. It is verified by comparison with experimental data reported by Laboratoire Nationae D'Hydraulique, Chatou, France, that the evolution from a smooth bed to sand dunes is determined by mutation in the bed load transport. This paper presents results that may offer theoretical explanations to the experimental observations. It is also an attempt to apply the state-of-the-art nonlinear science to the classical sediment transport mechanics.

  17. Profilaxis de los puentes óseos fisarios mediante interposición de injerto autólogo de periostio. Estudio experimental en conejos

    OpenAIRE

    1994-01-01

    Se ha realizado un trabajo experimental sobre la profilaxis de los puentes óseos epifisometafisarios mediante la interposición de injerto autólogo de periostio, planteando los siguientes objetivos: 1) Conseguir una barrera epifisometafisaria que impida la comunicación de los vasos epifisarios y metafisarios y 2) Estudiar la capacidad condrogénica del periostio. Se han utilizado 48 conejos, distribuidos en dos Series de cuatro Grupos cada una, según el momento del sacrificio a l...

  18. Estudio experimental del Sistema de Albañilería Integral en la construcción de viviendas sismorresistentes

    OpenAIRE

    Orta, B.; Bustamante, R.(Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Mexico City, Mexico); Adell, J. M.

    2012-01-01

    This paper presents the application of the Integral Masonry System (IMS) to the construction of earthquake resistant houses and its experimental study. To verify the security of this new type of building in seismic areas of the third world two prototypes have been tested, one with adobe and the other with hollow brick. In both cases it’s a two-story 6x6x6 m3 house built to scale 1/2. The tests are carried out at the Laboratory of Antiseismic Structures of the Department...

  19. Estudio experimental de la inducción electromagnética entre dos bobinas: dependencia con la corriente eléctrica

    OpenAIRE

    Arribas Garde, Enrique; Escobar García, Isabel; Nájera López, Alberto; Villalba Montoya, José Manuel; Ferreira da Cunha, Luciana; Beléndez Vázquez, Augusto

    2014-01-01

    En este artículo se muestran un conjunto de sencillas experiencias de laboratorio que ilustran el fenómeno de la inducción electromagnética. El dispositivo experimental, análogo a un transformador, está formado por dos bobinas magnéticamente acopladas conectadas a un generador de corriente alterna sinusoidal de frecuencia variable. Midiendo la tensión inducida en la bobina del secundario en función de la corriente que hay en la bobina del primario se obtiene una dependencia lineal. Los result...

  20. Estudio experimental de la inducción electromagnética entre dos bobinas: Dependencia con la corriente eléctrica

    OpenAIRE

    Villalba, José Manuel; Ferreira, Luciana; Arribas,Enrique; Nájera,Alberto; Beléndez,Augusto

    2015-01-01

    En este artículo se muestran un conjunto de sencillas experiencias de laboratorio que ilustran el fenómeno de la inducción electromagnética. El dispositivo experimental, análogo a un transformador, está formado por dos bobinas magnéticamente acopladas conectadas a un generador de corriente alterna sinusoidal de frecuencia variable. Midiendo la tensión inducida en la bobina del secundario en función de la corriente que hay en la bobina del primario ...

  1. Estudio experimental de la inducción electromagnética entre dos bobinas: Dependencia con la corriente eléctrica

    OpenAIRE

    Villalba Montoya, José Manuel; Ferreira, Luciana; Arribas Garde, Enrique; Nájera López, Alberto; Beléndez Vázquez, Augusto

    2014-01-01

    En este artículo se muestran un conjunto de sencillas experiencias de laboratorio que ilustran el fenómeno de la inducción electromagnética. El dispositivo experimental, análogo a un transformador, está formado por dos bobinas magnéticamente acopladas conectadas a un generador de corriente alterna sinusoidal de frecuencia variable. Midiendo la tensión inducida en la bobina del secundario en función de la corriente que hay en la bobina del primario se obtiene una dependencia lineal. Los result...

  2. Radiación y temperatura en el periodo 1990-1999 en el campo experimental de «El Ardal» (Murcia: estudio preliminar

    Directory of Open Access Journals (Sweden)

    Francisco Belmonte Serrato

    2002-01-01

    Full Text Available Este trabajo constituye una primera aproximación al análisis de las series de radiación y temperatura registradas en la estación meteorológica del campo experimental de «El Ardal» en el periodo 1990-1999. Los resultados iniciales, indican un aumento progresivo de la radiación global y de la temperatura a lo largo de los diez años del periodo de registro, al mismo tiempo que la radiación reflejada desde la superficie del suelo (albedo, registra una tendencia decreciente.

  3. Introduction to Bed Bugs

    Science.gov (United States)

    The common bed bug (Cimex lectularius) is a pest – feeding on blood, causing itchy bites and generally irritating their human hosts. EPA and other agencies all consider bed bugs a public health pest, but bed bugs are not known to transmit disease.

  4. Perspectiva aptitudinal-vocacional de bachilleres de la región capital de Venezuela: Prueba diagnóstica aptitudinal-vocacional de la Universidad Nacional Experimental de la Fuerza Armada (caso de estudio

    Directory of Open Access Journals (Sweden)

    Antonio José Boada

    2016-09-01

    Full Text Available En el presente artículo se exponen los hallazgos de un estudio comparativo en el que se relacionó la valoración de perfiles aptitudinales y vocacionales de bachilleres cursantes del programa de inducción universitaria de la Universidad Nacional Experimental de la Fuerza Armada (UNEFA, localizado en la ciudad capital de Caracas, específicamente en Miranda Oriental (Guarenas-Guatire, Miranda Occidental (Ocumare del Tuy, Los Teques y Santa Teresa del Tuy, y el estado Vargas, en relación con el promedio de los resultados a nivel nacional. Por cada una de estas localidades, se presentaron resultados de forma jerárquica, conforme a las siguientes variables aptitudinales: habilidad verbal, habilidad numérica y habilidad lógico-abstracta. Por otra parte, en cuanto a la variable vocacional, se realizó una medición psicométrica de seis dimensiones o fortalezas: sabiduría, valor coraje, humanidad, justicia, templanza y trascendencia del carácter de los individuos en estudio. De este modo, una vez consolidada la valoración de los perfiles aptitudinales-vocacionales de los individuos que presentaron la prueba diagnóstica, se comparó dicho resultado de manera automática con el perfil, según criterio de cada una de las carreras ofrecidas por la institución universitaria antes mencionada. Así, mediante la aplicación de una fórmula de desviación porcentual, se logró determinar que los sujetos bachilleres de las localidades de Caracas y Vargas presentan una madurez vocacional-aptitudinal significativamente superior a los de Miranda y al promedio nacional. Ello diverge de los resultados obtenidos por bachilleres de las localidades mirandinas (oriental y occidental, cuyos resultados fueron inferiores al nivel promedio nacional.

  5. Estudio teórico y experimental sobre los morteros para muros resistentes de fábrica de ladrillo para la actualización de la Norma Básica MV 201-1972

    Directory of Open Access Journals (Sweden)

    Monterde Comba, Guillermo J.

    1984-12-01

    Full Text Available This theoretical and experimental study on cement or lime and cement mortars brings up to date the contents of Chapter 3: MORTARS, of Norm MV 201-1972 "Resistant brick-work walls" which lost its validity when disappeared portland cement P-250, substituted by portland cement PA-350 with active additions, prescribed in the new Standard RC-75 "Standard of general technical prescriptions for cements acceptance" being obligatory its fulfilment.

    El presente estudio teórico y experimental sobre morteros, de cemento o de cal y cemento, constituye la puesta al día del contenido del Capítulo 3º MORTEROS, de la Norma MV 201-1972 "Muros resistentes de fábrica de ladrillo'', que perdió su vigencia con la desaparición del cemento portland P-250, sustituido por el cemento portland PA-350 con adiciones activas prescrito en el nuevo Pliego RC-75 "Pliego de prescripciones técnicas generales para la recepción de cementos" de obligado cumplimiento.

  6. EXPERIMENTAL INVESTIGATION ON MESO-PORE STRUCTURE PROPERTIES OF BEDDED SALT ROCK%层状盐岩细观孔隙特性试验研究

    Institute of Scientific and Technical Information of China (English)

    纪文栋; 杨春和; 刘伟; 李铭铭

    2013-01-01

    孔隙特性是决定盐岩储库密闭性的关键因素。对层状盐岩中不同岩性的试样开展压汞法测试和电镜扫描试验,分析层状盐岩孔隙率与渗透率的关系,并对层状盐岩的孔隙结构、分布特性及其密封性能进行研究。压汞测试表明:盐岩、泥岩和泥质钙芒硝的孔隙率平均值分别为2.7%,6.0%和2.5%,与常规岩石对比发现层状盐岩的孔隙率处在非常低的水平。孔隙率与渗透率之间存在明显的关系:低孔隙率是低渗透率的充分非必要条件,而高渗透率是高孔隙率的充分非必要条件,高孔隙率的试样有时也会出现低渗透率的情况。对岩体渗透率影响最大的是相互连通的部分孔隙,一旦存在连通的孔隙,渗透率就会显著增加。电镜扫描结果显示,盐岩是典型的晶体构造,内部结构密实,无明显的孔隙存在。泥岩中黏土和有机质颗粒的差异会显著影响其孔隙性质,颗粒粒径大小不一且呈块状或卵石状的区域孔隙大量发育,颗粒均质、呈块状的区域结构密实,孔隙较不发育。泥岩和盐岩的交界面处并不是孔隙发育的区域,泥岩和盐岩相互咬合、嵌入及泥岩细小颗粒的填充使孔隙率降低。含泥盐岩(含盐泥岩)中局部孔隙较为发育,并且连通度较高,是渗流可能发生的区域,建议储气库设计建造时避免将关键部位设置在孔隙发育区域,以保障密闭性。本文的研究成果可为储气库的建造及密闭性分析提供指导。%The property of pore structure is the key issue for the tightness of storage caverns. Mercury injection porosimetry tests and scanning electron microscopy(SEM) tests are conducted for different lithological rocks in bedded salt rock. The relationship between porosity and permeability,pore structure,distribution characteristics, as well as the corresponding tightness properties,are analyzed. The mercury injection

  7. Experimental study on tar destruction in a two stage fixed-bed reactor%两段式固定床反应器中焦油脱除的实验研究

    Institute of Scientific and Technical Information of China (English)

    吴文广; 罗永浩; 陈祎; 苏毅; 陈亮; 王芸

    2012-01-01

    通过两段式固定床反应器实验,研究了热裂解、部分氧化和炭层转化三种方法对焦油脱除的效果,并研究了生物质种类、反应温度、停留时间、生物质焦的粒径及种类等因素对热解焦油的脱除和转化规律.结果表明,随着温度的升高,三种脱除方法中焦油生成量下降,且降幅逐渐减小,实验过程中无论采取何种方法,都难以将焦油完全脱除;部分氧化和炭层转化对焦油的脱除效果都较相同温度条件下的热裂解要好,且在焦油脱除效果上,炭层转化>部分氧化>热裂解;联合部分氧化和炭层转化可达最高的焦油脱除效率,三种生物质热解焦油经1000℃联合脱除后产量分别为,稻秆0.43%、玉米秆0.61%和杉木屑1.15%,转化率分别达到98.28%、97.23%和96.29%;相同实验条件下稻秆的热解焦油最容易脱除,这与其物料中含氧量较高有关;生物质焦种类对焦油的脱除效果影响较小.%Methods of thermal cracking, partial oxidation and char bed conversion on tar destruction has been investigated by a two stage fixed-bed reactor, effects of fuel type, temperature, residence time, char particle size and char type on tar destruction are considered. The result indicates that tar conversion efficiency increase with the second stage reactor temperature increasing in all three kinds of conversion methods. Partial oxidation and char bed conversion is more effective in tar destruction compared to thermal cracking. Associated with partial oxidation and thermal cracking, char bed can get least tar yield. Three kinds of biomass tar yield in the experimental condition of 1 000℃ is: rice straw 0.43% , corn straw 0. 61% and fir sawdust 1. 15% , and the corresponding tar conversion efficiency is 98.28% , 97. 23% and 96.29% respectively. Tar yield content of each conversion methods are decreasing with reactor temperature increase. It is really difficult to removal all tar

  8. Preliminary experimental study of bituminous coal gasification on dual fluidized beds%烟煤在双流化床中气化特性初步实验研究

    Institute of Scientific and Technical Information of China (English)

    武小军; 范晓旭; 陈文义; 初雷哲

    2012-01-01

    利用一套高3m的双流化床煤气化实验系统,以烟煤为燃料进行了气化初步实验研究.烟煤在气化炉中进行热解气化,生成的半焦经下返料器送入燃烧炉进行燃烧,通过高温循环灰携带能量供给气化炉.通过调整气化炉内料层高度改变燃料在气化炉内的停留时间,从而影响气化效果,料层高度可以通过气化炉内压差进行监测.烟煤气化达到稳定工况时,燃烧炉和气化炉的温度和压差基本保持稳定.燃气热值为5.53 MJ/m3,尚未达到中热值标准,原因在于实验装置规模较小导致散热损失较大,同时返料器以空气为返料风降低了燃气品质.%Gasification experiments on bituminous coal were made in an experimental system of dual fluidized beds with 3 m in height. Gasifier was used for coal pyrolysis/gasification. Semicarbon was sent into burner for combustion by U-valve. Energy for gasification was carried by high temperature cycle ash. Status of gasification can be influenced by residence time of fuel which can be changed by adjusting the bed material level in gasifier. Differential pressures in gasifier were used for analyzed the bed material level. The temperature and differential pressure in gasifier and burner maintained stability when gasification condition operated steadily. The calorific value of gas was 5.53 MJ/Nm3 and didn't reach the standard of medium heat value. The cause is that the heat loss is bigger in small size and gas quality was decreased by the air which is used as return wind.

  9. Efectividad de una intervención formativa en prevención de úlceras por presión en una unidad de cuidados intensivos quirúrgica: un estudio cuasi experimental Effectiveness of an educational intervention in pressure ulcer prevention in a surgical intensive care unit: a quasi experimental study

    Directory of Open Access Journals (Sweden)

    M.ª Jesús Wandosell Picatoste

    2012-09-01

    Full Text Available Uno de los indicadores más relevantes para evaluar la seguridad del paciente es la incidencia de eventos adversos (EA. Las úlceras por presión (UPP son un EA con una incidencia muy elevada en las unidades de cuidados intensivos. El objetivo de este estudio es valorar la efectividad de una intervención formativa en prevención de UPP a través de la valoración de la incidencia y la gravedad de las lesiones en una unidad de cuidados intensivos quirúrgicos. Se llevó a cabo un estudio cuasi experimental de controles antes-después. Los resultados muestran que la incidencia de UPP disminuye tras la intervención formativa.One of the most relevant indicators to assess patient safety is the incidence of adverse events (AE. Pressure Ulcers (PU are an AE with a high incidence in intensive care units. The aim of this study is to evaluate the effectiveness of a formative intervention on prevention of PU through the assessment of the incidence and the severity of PU in the pre and the post intervention periods, in an intensive care surgical unit. We have carried out a quasi experimental study of pre and post controls. The results show that the incidence of PU is lower after the formative intervention.

  10. Bed Bugs (Cimex lectularius) as Vectors of Trypanosoma cruzi

    Science.gov (United States)

    Salazar, Renzo; Castillo-Neyra, Ricardo; Tustin, Aaron W.; Borrini-Mayorí, Katty; Náquira, César; Levy, Michael Z.

    2015-01-01

    Populations of the common bed bug, Cimex lectularius, have recently undergone explosive growth. Bed bugs share many important traits with triatomine insects, but it remains unclear whether these similarities include the ability to transmit Trypanosoma cruzi, the etiologic agent of Chagas disease. Here, we show efficient and bidirectional transmission of T. cruzi between hosts and bed bugs in a laboratory environment. Most bed bugs that fed on experimentally infected mice acquired the parasite. A majority of previously uninfected mice became infected after a period of cohabitation with exposed bed bugs. T. cruzi was also transmitted to mice after the feces of infected bed bugs were applied directly to broken host skin. Quantitative bed bug defecation measures were similar to those of important triatomine vectors. Our findings suggest that the common bed bug may be a competent vector of T. cruzi and could pose a risk for vector-borne transmission of Chagas disease. PMID:25404068

  11. Bed bugs (Cimex lectularius) as vectors of Trypanosoma cruzi.

    Science.gov (United States)

    Salazar, Renzo; Castillo-Neyra, Ricardo; Tustin, Aaron W; Borrini-Mayorí, Katty; Náquira, César; Levy, Michael Z

    2015-02-01

    Populations of the common bed bug, Cimex lectularius, have recently undergone explosive growth. Bed bugs share many important traits with triatomine insects, but it remains unclear whether these similarities include the ability to transmit Trypanosoma cruzi, the etiologic agent of Chagas disease. Here, we show efficient and bidirectional transmission of T. cruzi between hosts and bed bugs in a laboratory environment. Most bed bugs that fed on experimentally infected mice acquired the parasite. A majority of previously uninfected mice became infected after a period of cohabitation with exposed bed bugs. T. cruzi was also transmitted to mice after the feces of infected bed bugs were applied directly to broken host skin. Quantitative bed bug defecation measures were similar to those of important triatomine vectors. Our findings suggest that the common bed bug may be a competent vector of T. cruzi and could pose a risk for vector-borne transmission of Chagas disease.

  12. CÁNCER Y TERAPÉUTICA CON PRODUCTOS DE LA COLMENA. REVISIÓN SISTEMÁTICA DE LOS ESTUDIOS EXPERIMENTALES Cancer therapy with bee products. Systematic review of experimental studies

    Directory of Open Access Journals (Sweden)

    Andrés Jagua-Gualdrón

    2012-04-01

    Full Text Available Antecedentes. Los productos de la colmena se han utilizados desde hace más de dos milenios con fines terapéuticos. Conceptos teóricos basados en la composición de los productos hacen pensar que podrían ser de utilidad en el manejo del cáncer. Objetivo. Resumir la evidencia experimental disponible en la actualidad sobre el uso de los productos de la colmena en el manejo del cáncer. Material y métodos. Se realizó una revisión sistemática de los estudios experimentales publicados a través de las bibliotecas digitales PUBMED, LiLACS y OVID en los cuales se evaluara la utilidad del uso de los distintos productos de la colmena sobre cultivos de células tumorales o sobre modelos animales de cáncer. Se realizó un análisis cualitativo de la información y se construyeron tablas de resumen. Resultados. La búsqueda arrojó un total de 391 resultados de los cuales únicamente 55 cumplieron los criterios de inclusión. El veneno de abejas, la miel y el propóleo son los productos con un mayor número de publicaciones. La mayoría son estudios in vitro y son pocos los modelos en animales realizado. Se describen los mecanismos de acción a través de los cuales estos podrían llegar a ejercer acciones farmacológicas útiles en el manejo del cáncer. Conclusión. La aplicación de los productos de la colmena en el cáncer es un campo incipiente pero prometedor de investigación. Existe evidencia experimental que documenta la plausibilidad biológica de este uso. Es necesario realizar modelos animales que permitan describir el comportamiento de los productos y documentar su seguridad y utilidad terapéutica en el cáncer.Background. The beehive products have been used for more than two millennia with therapeutic purposes. Theoretical models based on the composition of products suggest that might be useful in cancer management. Objective. To summarize experimental evidence available to date on the use of beehive products in cancer management

  13. Experimental investigation of wood chip gasification using downdraft fixed bed gasifier%基于下吸式固定床的木片气化试验

    Institute of Scientific and Technical Information of China (English)

    马中青; 叶结旺; 赵超; 孙庆丰; 张齐生

    2016-01-01

    Gasification is a thermo-chemical process to convert carbonaceous materials into gaseous products which could be used as a fuel in engines for power generation or in boiler for heat supply. This paper investigated the effect of equivalence ratio (ER) on the gasification performance in terms of the temperature in the gasifier, the composition distribution of the producer gas, and the tar content in the producer gas using a lab-scale downdraft fixed bed gasifier fed by Pinus sylvestris wood chips. In addition, the characteristics of gasification byproducts, namely bio-char and bio-tar, were analyzed. The proximate and ultimate analysis, the surface morphology, the surface area, and the pore size distribution of wood charcoal were obtained by the scanning electron microscopy (SEM) and the Brunauer-Emmett-Teller (BET) method. The components of light tar and heavy tar were obtained by the gas chromatography-mass spectrometry (GC-MS). The results showed that the optimal ER was 0.251 with the maximum LHV of producer gas (4.55 MJ/Nm3 along with CO of 17.47%, H2 of 14.67%, CO2 of 12.43%, and CH4 of 2.12%), a minimum tar content of 350 mg/Nm3, and a maximum cold gas efficiency of 65.46%. The charcoal was a porous material with a high heating value of 28.17 MJ/kg and a high BET surface area 342 m2/g which could potentially be feedstock for the production of briquettes fuel and activated carbon. The light tar was mainly composed of phenols (36.75%), acetic acid (22.14%) and ketones (13.73%). After refining and dilution, the light tar could be a potential substance to produce plant growth regulator. The heavy tar was mainly composed of heterocyclic aromatics (59.98%), light aromatics (1 ring) (4.71%) and light polycyclic aromatic hydrocarbons (2-3 ring) (16.48%). The heavy tar could be a potential feedstock for aromatic chemicals production.%樟子松木材是中国一种重要的生物质能源原料,通过气化技术可将其转化为高热值生物燃气,用于内燃

  14. HTR-Proteus Pebble Bed Experimental Program Cores 5,6,7,&8: Columnar Hexagonal Point-on-Point Packing with a 1:2 Moderator-to-Fuel Pebble Ratio

    Energy Technology Data Exchange (ETDEWEB)

    Bess, John D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Sterbentz, James W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Snoj, Luka [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lengar, Igor [Idaho National Lab. (INL), Idaho Falls, ID (United States); Koberl, Oliver [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    PROTEUS is a zero-power research reactor based on a cylindrical graphite annulus with a central cylindrical cavity. The graphite annulus remains basically the same for all experimental programs, but the contents of the central cavity are changed according to the type of reactor being investigated. Through most of its service history, PROTEUS has represented light-water reactors, but from 1992 to 1996 PROTEUS was configured as a pebble-bed reactor (PBR) critical facility and designated as HTR-PROTEUS. The nomenclature was used to indicate that this series consisted of High Temperature Reactor experiments performed in the PROTEUS assembly. During this period, seventeen critical configurations were assembled and various reactor physics experiments were conducted. These experiments included measurements of criticality, differential and integral control rod and safety rod worths, kinetics, reaction rates, water ingress effects, and small sample reactivity effects (Ref. 3). HTR-PROTEUS was constructed, and the experimental program was conducted, for the purpose of providing experimental benchmark data for assessment of reactor physics computer codes. Considerable effort was devoted to benchmark calculations as a part of the HTR-PROTEUS program. References 1 and 2 provide detailed data for use in constructing models for codes to be assessed. Reference 3 is a comprehensive summary of the HTR-PROTEUS experiments and the associated benchmark program. This document draws freely from these references. Only Cores 9 and 10 are evaluated in this benchmark report due to similarities in their construction. The other core configurations of the HTR-PROTEUS program are evaluated in their respective reports as outlined in Section 1.0. Cores 9 and 10 were evaluated and determined to be acceptable benchmark experiments.

  15. HTR-PROTEUS PEBBLE BED EXPERIMENTAL PROGRAM CORES 5, 6, 7, & 8: COLUMNAR HEXAGONAL POINT-ON-POINT PACKING WITH A 1:2 MODERATOR-TO-FUEL PEBBLE RATIO

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess

    2013-03-01

    PROTEUS is a zero-power research reactor based on a cylindrical graphite annulus with a central cylindrical cavity. The graphite annulus remains basically the same for all experimental programs, but the contents of the central cavity are changed according to the type of reactor being investigated. Through most of its service history, PROTEUS has represented light-water reactors, but from 1992 to 1996 PROTEUS was configured as a pebble-bed reactor (PBR) critical facility and designated as HTR-PROTEUS. The nomenclature was used to indicate that this series consisted of High Temperature Reactor experiments performed in the PROTEUS assembly. During this period, seventeen critical configurations were assembled and various reactor physics experiments were conducted. These experiments included measurements of criticality, differential and integral control rod and safety rod worths, kinetics, reaction rates, water ingress effects, and small sample reactivity effects (Ref. 3). HTR-PROTEUS was constructed, and the experimental program was conducted, for the purpose of providing experimental benchmark data for assessment of reactor physics computer codes. Considerable effort was devoted to benchmark calculations as a part of the HTR-PROTEUS program. References 1 and 2 provide detailed data for use in constructing models for codes to be assessed. Reference 3 is a comprehensive summary of the HTR-PROTEUS experiments and the associated benchmark program. This document draws freely from these references. Only Cores 9 and 10 are evaluated in this benchmark report due to similarities in their construction. The other core configurations of the HTR-PROTEUS program are evaluated in their respective reports as outlined in Section 1.0. Cores 9 and 10 were evaluated and determined to be acceptable benchmark experiments.

  16. 刚果(金)某硫化铜钴精矿沸腾焙烧试验研究%Experimental Study on Fluidized Bed Roasting of Copper-cobalt Sulfide Concentrate from Congo DRC

    Institute of Scientific and Technical Information of China (English)

    李鑫; 周韫; 王含渊

    2015-01-01

    针对刚果(金)某铜钴矿选矿所得硫化铜钴精矿进行了沸腾焙烧试验研究。研究表明,在焙烧温度620℃、空气线速度0�43 m/s、风矿比3.33 m3/kg的条件下,硫化铜钴精矿焙烧效果较好。焙砂和焙烧烟尘酸浸试验结果进一步验证了最佳焙烧条件,焙砂铜、钴、铁浸出率分别为96.43%,87.06%和10.89%,焙烧烟尘铜、钴、铁浸出率分别为96.32%,84.02%和17.12%。试验研究结果为该类型铜钴矿选冶联合工艺选择及后期工业化应用提供了实验数据与技术支持。%An experimental study was carried out on the fluidized bed roasting of copper⁃cobalt sulfide concentrate obtained after processing of copper⁃cobalt ores from Congo DRC. It is suggested that a better effect be obtained for the roasting of copper⁃cobalt concentrate at a temperature of 620℃, with linear velocity of air at 0.43 m/s, air/ore ratio of 3.33 m3/kg. The further acid leaching test of calcine and roasting dust testified the optimum roasting condition. The leaching rates of Cu, Co, Fe reached 96. 43%, 87. 06%, 10. 89%, respectively, from the calcine, and 96. 32%, 84�02%, 17.12%, respectively, from the roasting dust. The experiment result can provide some sort of experimental reference and technical support for the selection of a combined process of concentrating and metallurgy, as well as the following industrialization of fluidized bed roasting technique for such copper⁃cobalt sulfide concentrate in future.

  17. Fluidized-bed reactors processes and operating conditions

    CERN Document Server

    Yates, John G

    2016-01-01

    The fluidized-bed reactor is the centerpiece of industrial fluidization processes. This book focuses on the design and operation of fluidized beds in many different industrial processes, emphasizing the rationale for choosing fluidized beds for each particular process. The book starts with a brief history of fluidization from its inception in the 1940’s. The authors present both the fluid dynamics of gas-solid fluidized beds and the extensive experimental studies of operating systems and they set them in the context of operating processes that use fluid-bed reactors. Chemical engineering students and postdocs as well as practicing engineers will find great interest in this book.

  18. Some hydrodynamic aspects of 3-phase inverse fluidized bed

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Hydrodynamics of 3-phase inverse fluidized bed is studied experimentally using low density particles for different liquid and gas velocities.The hydrodynamic characteristics studied include pressure drop, minimum liquid and gas fluidization velocities and phase holdups. The minimum liquid fluidization velocity determined using the bed pressure gradient, decreases with increase in gas velocity. The axial profiles of phase holdups shows that the liquid holdup increases along the bed height, whereas the solid holdup decreases down the bed. However, the gas holdup is almost uniform in the bed.

  19. Saliencia de la mortalidad y su influencia en motivos identitarios individuales y colectivos: un estudio experimental / Mortality salience and its influence on individual and collective identity motives: an experimental study

    Directory of Open Access Journals (Sweden)

    Sebastián Campos

    2016-06-01

    Full Text Available RESUMEN: La presente investigación busca determinar el impacto de la saliencia de la mortalidad en motivos identitarios individuales y colectivos, como la autoestima, la eficacia, la pertenencia, la distintividad, la continuidad y el significado. Se hipotetizó que la conciencia de la propia muerte potenciaría, a nivel individual y colectivo, los motivos identitarios descritos. A través de un diseño experimental, se encontró que a nivel de identidad individual el grupo experimental (expuesto a la saliencia de la propia mortalidad mostró puntuaciones marginalmente más elevadas que el grupo de control en los motivos de autoestima y de distintividad, y puntuaciones significativamente más elevadas en el motivo de continuidad. A nivel de identificación colectiva no se aprecia efecto alguno de la mortalidad sobre los motivos identitarios. ABSTRACT: The present investigation intends to determine mortality salience’s impact on individual and collective identity, through identity motives such as self-esteem, efficacy, belongingness, distinctiveness, continuity and meaning. It was hypothesized that the awareness of one’s own death would boost the described identity motives at both individual and collective levels. Throughout an experimental design it was found that, for individual identity, the experimental group (exposed to mortality salience showed marginally higher punctuations than the control group for the self-esteem and distinctiveness motives and significantly higher punctuations for the continuity motive. At the collective identity level mortality salience has no effect on the identity motives.

  20. Experimental Study on Mining Influence in Coal Mining Area with Loose Sand Bed%松散沙层煤矿区采动影响试验

    Institute of Scientific and Technical Information of China (English)

    刘立忠; 李虎民; 姜升

    2015-01-01

    The development and sustainability of intensive coal mines are restricted seriously by the coal mining under villages,which needed to be addressed. The current method is to relocate the involved villages,but there are some disadvanta-ges such as high cost,lack of land and the residents′reluctance to move. Therefore,reconstruction of the villagers′houses be-fore mining in the would-be subsidence area serves as a new way to prevent the coal mining under villages. In Xiaojihan Coal Mine,the observation of building anti-deformation and surface movement are made respectively in the testing building and the observation stations in order to make experimental study on the mining effect and mining without relocation. The result shows that the villagers′houses with anti-deformation structure could be resistant to the mining influence. It is feasible to make mining without relocation in the mining area with good application value.%村庄压煤问题严重制约着村庄密集型煤矿的发展和生产接续,亟待解决。目前的解决方法是对涉及到的村庄进行搬迁,但这样做有成本高、用地指标紧张和农民不愿搬离原址等弊端。因此,充分利用拟沉陷区进行村庄采前就地重建为村庄压煤问题的解决提供了新思路。通过小纪汗煤矿抗变形结构试验房和地表移动变形观测站,进行建筑物变形观测和地表移动变形观测,开展采动区影响和不搬迁开采试验研究。结果表明:采取相应抗变形结构的民房可以抵抗该矿的采动影响,可以进行该地区的不搬迁开采推广,具有很好的应用价值。

  1. Experimental study and by Monte Carlo of a prototype of hodoscopic of fibre optics for high resolution applications; Estudio experimental y por Monte Carlo de un prototipo de hodoscopio de fibras opticas para aplicaciones de alta resolucion

    Energy Technology Data Exchange (ETDEWEB)

    Granero, D.; Blasco, J. M.; Sanchis, E.; Gonzalez, V.; Martin, J. D.; Ballester, F.; Sanchis, E.

    2013-07-01

    The purpose of this work is to test the response of a system composed of 21 scintillators radiation fibres and its electronics as proof of the validity of the System. For this it has radiated test system with a source of verification of Sr-90. In addition, performed Monte Carlo simulations of the system by comparing the results of the simulations with those obtained experimentally. Moreover taken an approximation to the behavior of a hodoscopic composed of 100 scintillators, transverse fibers between if, in proton therapy, conducting different Monte Carlo simulations. (Author)

  2. Estudio experimental del Sistema de Albañilería Integral en la construcción de viviendas sismorresistentes. Experimental study of the Integral Masonry System in the construction of earthquake resistant houses

    OpenAIRE

    Bustamante Montoro, Rosa; Orta Rial, María Belén; Adell Argiles, Josep Maria

    2012-01-01

    This paper presents the application of the Integral Masonry System (IMS) to the construction of earthquake resistant houses and its experimental study. To verify the security of this new type of building in seismic areas of the third world two prototypes have been tested, one with adobe and the other with hollow brick. In both cases it’s a two-story 6x6x6 m3 house built to scale 1/2. The tests are carried out at the Laboratory of Antiseismic Structures of the Departmen...

  3. Un estudio experimental sobre el Machismo

    Directory of Open Access Journals (Sweden)

    Nuria Cortada de Kohan

    1970-01-01

    Full Text Available Using Thurstome´s equal-intervals technique a scale was constructed to measure "machismo" The origins of Latin American "machismo" was analized in a social and historical context, and related to cultural traditions of Southerns Europe. Scale M, an adaptation of Adorno´s scale F (to measure authoritarianism, Holtzman´s Test Form A, and a socio-economic questionnaire were applied to two groups of Ss; 20 University students¡ and 13 workers from the "Villas Miseria" of Buenos Aires. Significant results were found, at the. 001 level for both scales M and F; students were significantly less "machistas" and authoritarians than workers. Students had higher scores in the variables FA, M, I, end P of Holtzman´s Test, and lower in At, Sx, Ax, and Ho.

  4. Estudio de la aptitud física relacionada a la salud y composición corporal en escolares del nivel primario y secundario del colegio experimental de aplicación – UNE 2009

    OpenAIRE

    Saulo Salinas

    2011-01-01

    Los objetivos centrales de este estudio son: (1) Identificar y describir los niveles de aptitud física relacionada a la salud, (2) Identificar y describir las características de la composición corporal en los escolares de ambos sexos y (3) Determinar las diferencias de la aptitud física asociada a la salud y la composición corporal en función de la edad, sexo y turno de estudio. El diseño del estudio fue descriptivo comparativo. Se estudió a 1173 escolares (569 F- 604 M) de los niveles: prima...

  5. Fluidized bed calciner apparatus

    Science.gov (United States)

    Owen, Thomas J.; Klem, Jr., Michael J.; Cash, Robert J.

    1988-01-01

    An apparatus for remotely calcining a slurry or solution feed stream of toxic or hazardous material, such as ammonium diurante slurry or uranyl nitrate solution, is disclosed. The calcining apparatus includes a vertical substantially cylindrical inner shell disposed in a vertical substantially cylindrical outer shell, in which inner shell is disposed a fluidized bed comprising the feed stream material to be calcined and spherical beads to aid in heat transfer. Extending through the outer and inner shells is a feed nozzle for delivering feed material or a cleaning chemical to the beads. Disposed in and extending across the lower portion of the inner shell and upstream of the fluidized bed is a support member for supporting the fluidized bed, the support member having uniform slots for directing uniform gas flow to the fluidized bed from a fluidizing gas orifice disposed upstream of the support member. Disposed in the lower portion of the inner shell are a plurality of internal electric resistance heaters for heating the fluidized bed. Disposed circumferentially about the outside length of the inner shell are a plurality of external heaters for heating the inner shell thereby heating the fluidized bed. Further, connected to the internal and external heaters is a means for maintaining the fluidized bed temperature to within plus or minus approximately 25.degree. C. of a predetermined bed temperature. Disposed about the external heaters is the outer shell for providing radiative heat reflection back to the inner shell.

  6. Estudio del horizonte local

    OpenAIRE

    Ros Ferré, Rosa Maria

    2009-01-01

    El estudio del horizonte es fundamental para poder facilitar las primeras observaciones de los alumnos en un centro educativo. Un simple modelo, que debe realizarse para cada centro, nos permite facilitar el estudio y la comprensión de los primeros rudimentos astronómicos. El modelo construido se presenta a su vez como un sencillo modelo de reloj ecuatorial y a partir de él se pueden construir otros modelos (horizontal y vertical).

  7. HW粗煤泥流化床分选试验研究与工艺优化%Experimental study and process optimization on separation of coarse slime using HW fluidized bed

    Institute of Scientific and Technical Information of China (English)

    张祖军

    2014-01-01

    This paper introduces principle and characters of HW fluidized bed sorting ma-chine for coarse slime��The HW fluidized bed separation experimental study of coarse slime with the diameter 2~0��074 mm in Baizhuagn Coal preparation plant has been conducted��The effects between velocity of water and slime with different diameter on the separation have been re-searched��The results showed that the technological process in Baizhuagn Coal preparation plant was optimized and HW sorting machine has been used for recover coarse slime with the diameter from 0��2~2 mm��The probable deviation of separation can be 0��08~0��1 1��After the technologi-cal process has been optimized,under the same ash of clean coal condition,clean coal yield could increase 4��09%.%介绍了HW粗煤泥流化床分选机的分选原理及特点,并对白庄煤矿选煤厂2~0��074 mm的粗煤泥进行HW流化床分选相关试验,探究了上升水流速对不同粒级煤泥的分选效果的影响.试验结果表明,针对白庄煤矿选煤厂的生产情况进行工艺优化,最终决定采用 HW粗煤泥分选机回收2~0��2 mm粒级粗煤泥,分选可能偏差达到0��08~0��11.经过改造后,选煤厂在保持精煤灰分不变的情况下,综合精煤产率提高了4��09%.

  8. Empleo de isótopos radiactivos en estudios biocinéticos con animales de experimentación Use of radioisotopes in biokinetic models with experimental animals

    Directory of Open Access Journals (Sweden)

    F. R. Martín Martín

    2002-06-01

    Full Text Available En el presente trabajo se pretende realizar una revisión de las diferentes técnicas radioisotópicas que se utilizan con animales de experimentación a la hora de desarrollar modelos biocinéticos tanto de sustancias como de elementos químicos presentes en el medio ambiente. Dicha experimentación permite relacionar la exposición externa a un xenobiótico con la medida interna de la dosis en el organismo y, consecuentemente, sus posibles efectos tóxicos, todo ello con vistas a evaluar los efectos adversos que pudieran existir sobre la salud humana. Se hace hincapié en la macroautorradiografía de animal completo, técnica que permite la detección, localización y cuantificación del radionucleido de interés en diferentes órganos/tejidos del organismo y, por tanto, contribuye a la estimación de la dosis interna y al conocimiento del comportamiento biocinético del compuesto/elemento objeto de estudio. Se presentan algunos ejemplos de la utilidad de esta técnica en estudios biocinéticos con animales de experimentación de interés en diferentes áreas relacionadas con la Salud y el Medio Ambiente. Se destaca la utilidad que presenta esta experimentación a la hora de extrapolar el comportamiento metabólico de contaminantes de máxima radiotoxicidad en personas expuestas a la radiación ionizante, con el objeto de optimizar las evaluaciones dosimétricas y los protocolos de vigilancia que ayudan a conocer con más exactitud los daños de la exposición interna sobre la salud humana.Biokinetic models are useful tools to relate external exposures to internal measures of dose. The knowledge of internal dose and factors that influence absorption, distribution, metabolism, and elimination in experimental animals provide a scientific rationale for estimating low-dose human risk. A bioanalytical procedure to support biokinetic studies is the use of radiolabeled compounds, so that mass balance, autoradiography, and preliminary metabolism

  9. Transesophageal access to the cardiac cavities and descending thoracic aorta via echoendoscopy: An experimental study Acceso transesofágico a cavidades cardiacas y aorta torácica descendente mediante ecoendoscopia: Estudio experimental

    Directory of Open Access Journals (Sweden)

    A. López Martín

    2009-09-01

    Full Text Available Objective: the applications of endoscopic ultrasonography have diversified over recent years. The possibility of reaching cardiac territory has been successfully explored in experimental models, opening up a new field of possibilities for diagnostic and therapeutic interventions that were unthinkable until very recently. The aims set out in this study are to evaluate cardiac anatomy, its approach, the safety of the experimental procedure and the resulting morphological and histological changes after the procedure. Material and methods: the study has been performed on two adult pigs. They have undergone different surgical approaches to the cardiac cavities and descending thoracic aorta with excellent results. Results: different cardiac structures have been identified and operated upon (right auricle, left auricle, left ventricle, cardiac valves, as well as major vessels. The use of contrast, both intracavitary and from a peripheral vein, enabled us to verify the anatomical spaces studied. During the procedures we monitored for arrhythmias, hemodynamic behavior, possibility of infection by obtaining sample hemocultures before and after procedures, and response to punctures. Conclusions: the present study has enabled us to evaluate access to the heart from the esophageal lumen using endoscopic ultrasonography, with results that are very similar to those described in the current bibliography. However, we offer two novelties: puncture of the right auricle through the interauricular partition and puncture of the descending thoracic aorta, both performed with ease and apparent safety.Objetivo: las aplicaciones de la ultrasonografía endoscópica se han diversificado en los últimos tiempos. La posibilidad de acceder al territorio cardiaco se ha explorado en modelos experimentales con buenos resultados, abriendo un campo de nuevas posibilidades de intervencionismo diagnóstico y terapéutico hasta hace poco impensables. Los objetivos planteados en este

  10. Experimental methodology to study radionuclide sorption and migration in geological formations and engineered barriers of waste repositories; Metodologia experimental para estudios de sorcion y migracion de radionucleidos en formaciones geologicas y barreras de almacenamientos de residuos

    Energy Technology Data Exchange (ETDEWEB)

    Rojo Sanz, H.

    2010-07-01

    In Spain, the waste management options include either the possibility of a final storage in a deep geological repository (DGR) or the centralized temporal surface disposal (CTS). DGRs are based in a multi-barrier concept with the geological barrier and including the vitrified waste, the metal containers and engineered barriers such as compacted bentonite and cement-based materials. On the other hand, CTS mainly considers concrete and cement to confine the metal canisters containing the waste. Radionuclide migration will mainly take place by the existence of chemical concentration gradients being thus diffusion the main transport mechanism or by the existence of hydraulic gradients due to the existence of water-conductive fractures. Radionuclide sorption/retention on the materials composing the natural and engineered barriers is the fundamental process controlling contaminant migration. The evaluation of sorption parameters and the understanding of the different mechanisms leading to radionuclide retention are very important issues. The study of diffusion processes is very relevant as well. This paper describes the main experimental methodologies applied to analyse radionuclide transport in the different barriers of radioactive repositories. Particularly we focused on obtaining of retention parameters as distribution coefficients, kd, or retardation factors, Rf, and diffusion coefficients of radionuclides. (Author) 6 refs.

  11. Centerline Bed Elevation Profile of Sand Bed Channel due to Bar Formation

    Science.gov (United States)

    Tholibon, D. A.; Ariffin, J.; Abdullah, J.; Muhamad, N. S.

    2016-07-01

    Numerous data on bar formation have been accumulated yet the methods to predict bar geometry especially bar height are still insufficient. Objectives of this study to determine the trend in term of a significant difference of centreline bed elevation profile along the longitudinal distance. This can be investigate by carried out an experimental work in an erodible sand bed channel using a large-scale physical river model. The study included the various hydraulic characteristics with steady flow rates and sediment supply. An experimental work consists of four matrices of flow rate and channel width with other variables namely grains size and bed slope were kept constant. Analysis have included the discussion on a significant difference of centreline bed elevation profile along the longitudinal distance. As a conclusion the higher velocity in the smaller channel width have induced erosion of the banks that resulted in elevation increase while the larger flow rates have contributed to higher elevation.

  12. Tube erosion in bubbling fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Levy, E.K. [Lehigh Univ., Bethlehem, PA (United States). Energy Research Center; Stallings, J.W. [Electric Power Research Inst., Palo Alto, CA (United States)

    1991-12-31

    This paper reports on experimental and theoretical studies that were preformed of the interaction between bubbles and tubes and tube erosion in fluidized beds. The results are applicable to the erosion of horizontal tubes in the bottom row of a tube bundle in a bubbling bed. Cold model experimental data show that erosion is caused by the impact of bubble wakes on the tubes, with the rate of erosion increasing with the velocity of wake impact with the particle size. Wake impacts resulting from the vertical coalescence of pairs of bubbles directly beneath the tube result in particularly high rates of erosion damage. Theoretical results from a computer simulation of bubbling and erosion show very strong effects of the bed geometry and bubbling conditions on computed rates of erosion. These results show, for example, that the rate of erosion can be very sensitive to the vertical location of the bottom row of tubes with respect to the distributor.

  13. Bed Bugs FAQs

    Science.gov (United States)

    ... Bed bugs have been found in five-star hotels and resorts and their presence is not determined ... sleep. These areas include apartments, shelters, rooming houses, hotels, cruise ships, buses, trains, and dorm rooms. They ...

  14. Tapered bed bioreactor

    Science.gov (United States)

    Scott, Charles D.; Hancher, Charles W.

    1977-01-01

    A vertically oriented conically shaped column is used as a fluidized bed bioreactor wherein biologically catalyzed reactions are conducted in a continuous manner. The column utilizes a packing material a support having attached thereto a biologically active catalytic material.

  15. 循环流化床烟气脱硫模拟中试试验研究%Experimental Research on a Pilot-Scale Circulating Fluidized Bed for Flue Gas Desulfurization

    Institute of Scientific and Technical Information of China (English)

    冯斌; 李大骥; 周志良; 吴颖海; 杨军

    2001-01-01

    在东南大学热能工程研究所建立的φ600mm,处理烟气量达2000m3/h(标准状态,下同)的循环流化床烟气脱硫中试试验台上,进行了循环流化床烟气脱硫的试验研究.分别讨论了Ca与S的摩尔比、烟气流量、入口SO2浓度、反应温度等因素对脱硫效率影响.试验结果表明,Ca与S的摩尔比和反应温度的影响最为显著,烟气量和SO2入口浓度也有一定的影响,但不十分明显,说明循环流化床烟气脱硫工艺对锅炉负荷和燃煤煤种的变化有较好的适应性.%At present, SO2 pollution control of coal combustion is an urgenttask in the field of air pollution control in China. An experimental research was carried on the simulated pilot-scale test facility of Circulating Fluidized Bed for Flue Gas Desulfurization (CFB-FGD) whose diameter is 600mm and nominal flow rate of the flue gas is 2 000 m3/h in Thermal Engineering Research Institute of Southeast University. The Ca/S molar ratio and the reaction temperature have great influence on the efficiency of desulfurization, but the influences of the flow rate and SO2 inlet concentration are not obvious. So the result indicates that CFB-FGD technology is applicable for the variation of the boiler’s load and the coal used.

  16. Experimental Study on Synthesis Molecular Sieve Ashes of Circulating Fluidized Bed%利用循环流化床飞灰合成分子筛实验研究

    Institute of Scientific and Technical Information of China (English)

    姚刚; 卿山; 马林转; 岳争超; 何屏; 李瑛

    2009-01-01

    Experimental study showed when n (SiO2) /n (Al2O3)≈3.3, Na2O/SiO2 was 1.2~1.5, H2O/Na2O was 40~70, the gel temperature was 60 -70 ℃, time continued 2h, reaction temperature was 90 -95 ℃, the crystallization time continued 4 -6 h, the fly ash of circulating fluidized bed boiler could synthesize the molecular sieve of higher crystallinity. It had better characteristic peak of P zeolite by the characterization of XRD, good stability by TGA. The relative degree of crystallization was 53%.%利用循环流化床锅炉粉煤灰在n(SiO2)/n(Al2O3)≈3.3、Na2O/SiO2为1.2~L 5、H2O/Na2O为40~70、凝胶温度和时间分别为60-70℃、时间2 h、晶化反应温度在90-95℃,晶化时间为4-6 h的条件下可以合成出较高结晶度的分子筛,通过XRD表征发现,产品具有良好的P型分子筛特征峰,其相对结晶度为53%.热重分析可知其具有好的稳定性.

  17. Estudio de caso

    OpenAIRE

    Maciel-González-Durán, Gabriela

    2015-01-01

    El presente trabajo es un estudio de caso de acompañamiento emocional y psicoterapéutico. Se muestra el contexto general y el proceso de la consultante. El motivo principal de consulta fue una experiencia de secuestro y violación que ocasionó un cuadro de estrés post-traumático. Dentro del apartado del estudio de caso se hace referencia a las vivencias, significados y contexto de la consultante, se pretende demostrar el desarrollo que se fue llevando a cabo en la consultante, y se comparten f...

  18. Retrato de estudio. Sacerdote.

    OpenAIRE

    Ansede y Juanes

    2010-01-01

    1 fot.; papel; imagen 12,6 x 20 cm. - Retrato de estudio. Sacerdote. (2 copias. Gelatina D. O. P. mate montada sobre cartulina, medida total 12,6 x 20. Sello troquelado impreso del fotógrafo con letras doradas en ángulo inferior derecho de cartulina: "Ansede y Juanes - Salamanca"). - Procedencia: fondo Miguel de Unamuno. - Buena Conservación.

  19. de estudios observacionales

    Directory of Open Access Journals (Sweden)

    Erik von Elm

    2008-01-01

    un documento de explicación y elaboración al que puede accederse libremente en los sitios web de PLoS Medicine, Annals of Internal Medicine y Epidemiology. Esperamos que la declaración STROBE contribuya a mejorar la calidad de la publicación de los estudios observacionales.

  20. Resumen estudios sobre tabaquismo

    OpenAIRE

    Gónzalez, M.M. (M.)

    2009-01-01

    Este documento se realizó para publicar en la página Web de la Gerencia de Atención primaria del Área III. Este documento es una recopilación de estudios sobre tabaquismo. Gerencia de Atención Primaria Área III

  1. Hydrodynamic and Heat Transfer Characteristics of Magnetofluidized Beds

    Institute of Scientific and Technical Information of China (English)

    S.C.Saxena; R.Z.Qian

    1994-01-01

    To investigate the flow and heat-transfer behaviors of magnetofluidized beds,an experimental facility was designed.A constant uniform magnetic field is produced by a Helmhotz electromagnet.The nature of fluidization and heat-transfer characteristics,of a horizontal electrically heated tube immersed in the bed were measured.The bed material is iron shots.Depending upon the intensity of magneticfield(weak,moderate and strong),the bed pressure drop and heat transfer coefficient are classified into three ranges of magnetic fields.The range of variation of maximum magnetic-field intensity is from 0 to about 20690 A/m.

  2. Experimental Study on Channel Deposition of Viscous Debris Flow over Erodible Beds%动床条件下粘性泥石流沟道淤积实验研究

    Institute of Scientific and Technical Information of China (English)

    林雪平; 游勇; 柳金峰; 赵彦波; 刘曙亮

    2013-01-01

    泥石流淤积是危害建筑物的主要方式之一.为了探讨动床条件下泥石流沟道淤积规律,开展了不同泥石流重度、不同沟床物质重度、不同沟道坡度以及不同泥石流总量共4组单次淤积实验和1组不同沟道坡度下的泥石流连续淤积实验.实验结果表明,单次淤积时,泥石流淤积厚度随着沟道坡度的增加而减小,随着泥石流重度的增大而增大,随泥石流总量的增大而增大,受沟床物质重度变化的影响较小;连续淤积时,随着沟道坡度的增加,第2次淤积相对于第1次淤积结果依次表现为完全淤积、冲淤交替以及完全冲刷,且冲刷始于沟道前缘,逐渐向后缘发展.在分析泥石流淤积厚度的影响因素基础上,通过回归分析建立了动床条件下粘性泥石流沟道淤积厚度的经验预测公式:H=0.005x+ (1.63E-11)e(rc)-0.003ln(sinθ) +0.22V-0.02.%Debris flow deposition is one of the main hazards for buildings.In order to explore the law of debris flow deposition over erodible beds,we carried out 4 groups single siltation experiment and 1 group successive siltation experiment.The single deposition experimental result shows that deposition thickness increases with the increase of channel slope debris,the increase of debris flow density and the increase of the total amount of debris flow.The bed material density has a small effect on the deposition thickness.By continuous sedimentation,along with the increase of channel slope,the second experiment in turn presented as complete cholestasis,half deposition and half erosion and scouting silting completely,and erosion began at the leading edge,gradually backward to edge of development.On the basis of analyzing of the factors of debris flow deposition thickness,this article established the prediction formula of viscous debris flow single siltation thickness through regression analysis:H =0.005x + (1.63E-11)erc-0.003ln(sinθ) +0.22V-0.02.

  3. LIVE-BED SCOUR IN LONG CONTRACTIONS

    Institute of Scientific and Technical Information of China (English)

    Subhasish DEY; Rajkumar V.RAIKAR

    2006-01-01

    This paper presents a simple analytical model, developed using the energy and continuity equations,for the computation of the live-bed scour depth in long contractions. The model agrees satisfactorily with experimental data. Equations previously proposed in the literature for estimation of the equilibrium scour depth in long contractions are compared with experimental data. The comparison indicates that the equation given by Lim is the best predictor among those examined.

  4. Effect of bed particles to combustion of gases in fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Raiko, R.; Wallen, V.; Etelaeaho, R.; Correia, S. [Tampere Univ. of Technology (Finland). Energy and Process Engineering

    1997-10-01

    The objective of this project was to obtain experimental data on effects of sand particles to the combustion of gases. The effect of the surface area of the particles was tested using different sized particles. The fluidized bed reactor used in these experiments was a stainless-steel tube with an internal diameter of 42 mm surrounded by an electric heater. The test rig was built in the Laboratory of Energy and Process Engineering at Tampere University of Technology. In order to elucidate the possible changes of particle surface, microscopic and porosimetric studies were conducted with both fresh bed particles and used bed particles. These measurements indicate that carbon monoxide significantly reacts with oxygen in the particulate or emulsion phase of a fluidized bed, if the residence time is long enough. The reaction rate depends mainly on temperature, air coefficient, residence time and particle size of the solids. It seems that the combustion enhances if the average particle size increases. Whether this is caused by increased free path length or reduced specific surface area of the bed is yet unknown. The first might be more probable cause because the majority of reactions often took place in the freeboard right above the bed. It was clear that the bed hindered proper combustion in several cases. (orig.)

  5. Perspectives for Fluidized Bed Nuclear Reactor Technology using Rotating Fluidized Beds in a Static Geometry

    Science.gov (United States)

    Broqueville, Axel De; Wilde, Juray De

    The new concept of a rotating fluidized bed in a static geometry opens perspectives for fluidized bed nuclear reactor technology and is experimentally and numerically investigated. With conventional fluidized bed technology, the maximum attainable power is rather limited and maximum at a certain fluidization gas flow rate. Using a rotating fluidized bed in a static geometry, the fluidization gas drives both the centrifugal force and the counteracting radial gas-solid drag force in a similar way. This allows operating the reactor at any chosen sufficiently high solids loading over a much wider fluidization gas flow rate range and in particular at much higher fluidization gas flow rates than with conventional fluidized bed reactor technology, offering increased flexibility with respect to cooling via the fluidization gas. Furthermore, the centrifugal force can be a multiple of earth gravity, allowing radial gas-solid slip velocities much higher than in conventional fluidized beds. The latter result in gas-solid heat transfer coefficients one or multiple orders of magnitude higher than in conventional fluidized beds. The combination of dense operation and high fluidization gas flow rates allows process intensification and a more compact reactor design.

  6. Acoustic measurements of a liquefied cohesive sediment bed under waves

    Science.gov (United States)

    Mosquera, R.; Groposo, V.; Pedocchi, F.

    2014-04-01

    In this article the response of a cohesive sediment deposit under the action of water waves is studied with the help of laboratory experiments and an analytical model. Under the same regular wave condition three different bed responses were observed depending on the degree of consolidation of the deposit: no bed motion, bed motion of the upper layer after the action of the first waves, and massive bed motion after several waves. The kinematic of the upper 3 cm of the deposit were measured with an ultrasound acoustic profiler, while the pore-water pressure inside the bed was simultaneously measured using several pore pressure sensors. A poro-elastic model was developed to interpret the experimental observations. The model showed that the amplitude of the shear stress increased down into the bed. Then it is possible that the lower layers of the deposit experience plastic deformations, while the upper layers present just elastic deformations. Since plastic deformations in the lower layers are necessary for pore pressure build-up, the analytical model was used to interpret the experimental results and to state that liquefaction of a self consolidated cohesive sediment bed would only occur if the bed yield stress falls within the range defined by the amplitude of the shear stress inside the bed.

  7. Erosion of heat exchanger tubes in fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, E.K.; Flemmer, R.L.C.

    1991-01-01

    This final report describes the activities of the 3-year project entitled Erosion of Heat Exchanger Tubes In Fluidized Beds.'' which was completed at the end of 1990. Project accomplishments include the collection of a substantial body of wear data In a 24in. [times] 24in. fluidized bed, comparative wear results In a 6in. [times] 6in. fluidized bed, the development of a dragometer and the collection of a comprehensive set of drag force data in the 24in. [times] 24in. bed, Fast Fourier Transform (FFT) analysis of bubble probe data to establish dominant bubble frequencies in the 24in. [times] 24in. bed, the use of a heat flux gauge for measurement of heat transfer coefficients in the 24in. [times] 24in. bed and the modeling of the tube wear in the 24in. [times] 24in. bed. Analysis of the wear data from the 24in. square bed indicates that tube wear increases with increase in superficial velocity, and with increase in tube height. The latter effect is a result of the tubes higher up in the bed seeing greater movement of dense phase than tubes lower down In the bed. In addition, tube wear was found to decrease with increase in particle size, for constant superficial velocity. Three models of tube wear were formulated and provided acceptable prediction of wear when compared with the experimental data.

  8. Bed bug deterrence

    Directory of Open Access Journals (Sweden)

    Haynes Kenneth F

    2010-09-01

    Full Text Available Abstract A recent study in BMC Biology has determined that the immature stage of the bed bug (the nymph signals its reproductive status to adult males using pheromones and thus avoids the trauma associated with copulation in this species. The success of this nymphal strategy of deterrence is instructive. Against the background of increasing problems with bed bugs, this research raises the question whether pheromones might be used to control them. See research article http://www.biomedcentral.com/1741-7007/8/121

  9. in Spouted Bed

    Directory of Open Access Journals (Sweden)

    Bronislaw Buczek

    2013-01-01

    Full Text Available Samples of active coke, fresh and spent after cleaning flue gases from communal waste incinerators, were investigated. The outer layers of both coke particles were separately removed by comminution in a spouted bed. The samples of both active cokes were analysed by means of densities, mercury porosimetry, and adsorption technique. Remaining cores were examined to determine the degree of consumption of coke by the sorption of hazardous emissions (SO2, HCl, and heavy metals through its bed. Differences in contamination levels within the porous structure of the particles were estimated. The study demonstrated the effectiveness of commercial active coke in the cleaning of flue gases.

  10. Virtual Test Bed

    Science.gov (United States)

    2016-06-07

    SEP 1999 2. REPORT TYPE 3. DATES COVERED 00-00-1999 to 00-00-1999 4. TITLE AND SUBTITLE Virtual Test Bed 5a. CONTRACT NUMBER 5b. GRANT...Virtual Test Bed Donald T. Resio U.S. Army Engineer Research and Development Center Coastal and Hydraulics Laboratory Vicksburg, MS 39180-6199 Phone...into three parts: 1) assembly of field and laboratory data sets for testing ; 2) set-up of a benchmark system; and 3) exercising the benchmark system

  11. Effects of bed-load movement on flow resistance over bed forms

    Indian Academy of Sciences (India)

    Mohammad Hossein Omid; Masoud Karbasi; Javad Farhoudi

    2010-12-01

    The effect of bed-load transport on flow resistance of alluvial channels with undulated bed was experimentally investigated. The experiments were carried out in a tilting flume 250 mm wide and 12·5 m long with glass-sides of rectangular cross-section and artificial dune shaped floor that was made from Plexi-glass. Steady flow of clear as against sediment-laden water with different flow depths and velocities were studied in the experiments with a fine sand ($d_{50} =$ 0·5 mm). The results indicate that the transport of fine particles ($d_{50} =$ 0·5 mm) can decrease the friction factor by 22% and 24% respectively for smooth and rough beds. Increasing the bed-load size ($d_{50} =$ 2·84 mm) can decrease the friction factor by 32% and 39% respectively for smooth and rough beds. The decrease in flow resistance is due to filling up of the troughs of dunes. This separation zone is responsible for increasing the flow resistance. On the upstream side of dunes condition is similar to plane bed. Presence of bed-load causes to increase the shear velocity and hence increasing flow resistance. But decreasing in flow resistance is more and it causes to decrease the total flow resistance. Grains saturated the troughs in the bed topography, effectively helping in smoothening of bed irregularities.

  12. Efeitos da clonidina nas respostas cardiovasculares ao pinçamento aórtico infra-renal: estudo experimental no cão Efectos de la clonidina en las respuestas cardiovasculares al pinzamiento aórtico infra-renal: estudio experimental en el can Effects of clonidine on cardiovascular responses to infrarenal aortic cross-clamping: experimental study in dogs

    Directory of Open Access Journals (Sweden)

    Renato Viccário Achôa

    2003-09-01

    íaca e pressão arterial média, enquanto os valores das pressões do átrio direito e índice sistólico continuaram elevados. No grupo controle, os valores do índice de trabalho sistólico do ventrículo direito continuaram elevados enquanto os valores do índice cardíaco retornaram a valores próximos aos do controle. No grupo clonidina, os valores das pressões do átrio direito e da artéria pulmonar ocluída, e o índice sistólico, continuaram significantemente elevados. CONCLUSÕES: No cão, nas condições experimentais empregadas, a administração venosa contínua de clonidina atenua as respostas cardiovasculares decorrentes do pinçamento aórtico infra-renal.JUSTIFICATIVA Y OBJETIVOS: El pinzamiento aórtico infra-renal puede determinar alteraciones cardiovasculares. La clonidina, un a2-agonista, determina bradicardia y diminución de la presión arterial. El objetivo del estudio fue evaluar los efectos de la clonidina sobre la función cardiovascular, en canes sometidos a pinzamiento aórtico infra-renal. MÉTODO: El estudio aleatorio fue realizado en 16 canes, distribuidos en dos grupos: G Control - sin la utilización de clonidina y G Clon - clonidina, en la dosis inicial de 5 µg.kg-1, por vía venosa, inmediatamente antes del pinzamiento aórtico infra-renal, seguido de 2 µg.min-1.m² hasta el final del estudio. En todos los animales fue realizada ligadura infra-renal de la aorta, por 45 minutos. Los atributos hemodinámicos fueron estudiados en los momentos C (control, después 10 (Ao10 y 25 (Ao25 minutos del pinzamiento aórtico, y después 10 (DAo10 y 25 (DAo25 minutos del despinzamiento aórtico. RESULTADOS: Durante el pinzamiento aórtico, hubo diferencia significante entre los grupos, en relación a la frecuencia cardíaca, presión arterial media e índice cardíaco (G Control > G Clon. Después del despinzamiento aórtico hubo diferencia significante entre los grupos, en relación a la frecuencia cardíaca (G Control > G Clon y presiones del

  13. Nonlinear Mechanism of Bed Load Transport

    Institute of Scientific and Technical Information of China (English)

    XU Haijue; BAI Yuchuan; NG Chiu-On

    2009-01-01

    From the group movement of the bed load within the bottom layer, details of the nonlinear dynamic characteristics of bed load movement are discussed in this paper. Whether the sediment is initiated into motion cor-responds to whether the constant term in the equation is equal to zero. If constant term is zero and no dispersive force is considered, the equation represents the traditional Shields initiation curve, and if constant term is zero with-out the dispersive force being considered, then a new Shields curve which is much lower than the traditional one is got, The fixed point of the equation corresponds to the equilibrium sediment transport of bed load. In the mutation analysis, we have found that the inflection point is the demarcation point of breaking. In theory, the breaking point corresponds to the dividing boundary line, across which the bed form changes from flat bed to sand ripple or sand dune. Compared with the experimental data of Chatou Hydraulic Lab in France, the conclusions are verified.

  14. Surviving Bed Rest

    Science.gov (United States)

    ... your pregnancy — and your bed rest start a family tree that you can share with your child someday firm up your baby-name choices; use books and websites for ideas organize photo albums read anything — ... people (friends and family) whom you know will probably give gifts build ...

  15. MULTISTAGE FLUIDIZED BED REACTOR

    Science.gov (United States)

    Jonke, A.A.; Graae, J.E.A.; Levitz, N.M.

    1959-11-01

    A multistage fluidized bed reactor is described in which each of a number of stages is arranged with respect to an associated baffle so that a fluidizing gas flows upward and a granular solid downward through the stages and baffles, whereas the granular solid stopsflowing downward when the flow of fluidizing gas is shut off.

  16. Fluidized bed combustion chamber

    Energy Technology Data Exchange (ETDEWEB)

    Kullendorff, A.; Wikner, J.

    1985-03-25

    The chamber is confined in a pressure vessel. The lower part of the chamber has tilted parallel gutters up to the height of the fluidized bed. The slope of the gutter walls is 5 degrees-15 degrees and the top area of the gutters is 1.3 to 3 times larger than their bottom.

  17. Métodos Experimentales de Estudio de la Percepción Temprana del Habla/ Experimental Study Techniques for the Early Speech Perception/ Métodos Experimentais de Estudo da Percepção Precoce da Fala

    Directory of Open Access Journals (Sweden)

    Leonardo Francisco Barón Birchenall

    2014-07-01

    Full Text Available El estudio de la percepción temprana del habla surgió a comienzos de la década de los setenta, pero solo se desarrolló plenamente diez años después, debido a la aparición y adaptación de nuevos métodos empíricos y herramientas tecnológicas. En este artículo se presenta una revisión de los métodos experimentales que pueden ser utilizados para el estudio de la percepción del habla en niños menores de un año. También se refieren algunas de las conclusiones teóricas más relevantes que se han alcanzado gracias a su aplicación. Se pretende brindar un panorama del estado metodológico y teórico del estudio de la percepción del lenguaje hablado durante el primer año de vida.

  18. Effect of static bed height in the upper fluidized bed on flow behavior in the lower riser section of a coupled reactor

    Institute of Scientific and Technical Information of China (English)

    Dewu Wang; Chunxi Lu; Chaoyu Yan

    2009-01-01

    To study olefin reduction by using an auxiliary reactor for FCC naphtha upgrading, a large-scale cold model of a riser-bed coupled to an upper fluidized bed was established. The effect of static bed height in the upper fluidized bed on particle flow behavior in the lower riser was investigated experimentally. A restriction index of solids holdup was used to evaluate quantitatively the restrictive effect of the upper fluidized bed. Experimental results show that, under the restrictive effect of the upper fluidized bed, the riser could be divided into three regions in the longitudinal direction: accelerating, fully developed and restriction. The axial distribution of solids holdup in the riser is characterized by large solids holdup in the top and bottom sections and small solids holdup in the middle section. Overall solids holdup increased with increasing static bed height in the upper fluidized bed, while particle velocity decreased. Such restrictive effect of the upper fluidized bed could extend from the middle and top sections to the whole riser volume when riser outlet resistance is increased, which increases with increasing static bed height in the upper fluidized bed. The upper bed exerts the strongest restriction on the area close to the riser outlet.

  19. Influence of artificial ecological floating beds on river hydraulic characteristics

    Institute of Scientific and Technical Information of China (English)

    饶磊; 钱进; 敖燕辉

    2014-01-01

    The artificial ecological floating bed is widely used in rivers and lakes to repair and purify polluted water. However, the water flow pattern and the water level distribution are significantly changed by the floating beds, and the influence on the water flow is different from that of aquatic plants. In this paper, based on the continuous porous media model, a moveable two-layer combination model is built to describe the floating bed. The influences of the floating beds on the water flow characteristics are studied by numerical simulations and experiments using an experimental water channel. The variations of the water level distribution are discussed under conditions of different flow velocities ( v=0.1 m/s, 0.2 m/s, 0.30 m/s, 0.4 m/s), floating bed coverage rates (20%, 40%, 60%) and arrangement positions away from the channel wall ( D=0 m, 0.1 m, 0.2 m). The results indicate that the flow velocity increases under the floating beds, and the water level rises significantly under high flow velocity conditions in the upstream region and the floating bed region. In addition, the average rising water level value (ARWLV) increases significantly with the increase of the floating bed coverage rate, and the arrangement position of floating beds in the river can also greatly influence the water level distribution under a high-flow velocity condition (v³0.2 m/s) .

  20. VA National Bed Control System

    Data.gov (United States)

    Department of Veterans Affairs — The VA National Bed Control System records the levels of operating, unavailable and authorized beds at each VAMC, and it tracks requests for changes in these levels....

  1. Bathing a patient in bed

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000427.htm Bathing a patient in bed To use the sharing features on this page, please enable JavaScript. Some patients cannot safely leave their beds to bathe. For ...

  2. Pulsed atmospheric fluidized bed combustion

    Energy Technology Data Exchange (ETDEWEB)

    1989-11-01

    In order to verify the technical feasibility of the MTCI Pulsed Atmospheric Fluidized Bed Combustor technology, a laboratory-scale system was designed, built and tested. Important aspects of the operational and performance parameters of the system were established experimentally. A considerable amount of the effort was invested in the initial task of constructing an AFBC that would represent a reasonable baseline against which the performance of the PAFBC could be compared. A summary comparison of the performance and emissions data from the MTCI 2 ft {times} 2 ft facility (AFBC and PAFBC modes) with those from conventional BFBC (taller freeboard and recycle operation) and circulating fluidized bed combustion (CFBC) units is given in Table ES-1. The comparison is for typical high-volatile bituminous coals and sorbents of average reactivity. The values indicated for BFBC and CFBC were based on published information. The AFBC unit that was designed to act as a baseline for the comparison was indeed representative of the larger units even at the smaller scale for which it was designed. The PAFBC mode exhibited superior performance in relation to the AFBC mode. The higher combustion efficiency translates into reduced coal consumption and lower system operating cost; the improvement in sulfur capture implies less sorbent requirement and waste generation and in turn lower operating cost; lower NO{sub x} and CO emissions mean ease of site permitting; and greater steam-generation rate translates into less heat exchange surface area and reduced capital cost. Also, the PAFBC performance generally surpasses those of conventional BFBC, is comparable to CFBC in combustion and NO{sub x} emissions, and is better than CFBC in sulfur capture and CO emissions even at the scaled-down size used for the experimental feasibility tests.

  3. Comportamento hemodinâmico e metabólico do choque hemorrágico: estudo experimental no cão Comportamiento hemodinámico y metabólico del choque hemorrágico: estudio experimental en el can Hemorrhagic shock hemodynamic and metabolic behavior: experimental study in dogs

    Directory of Open Access Journals (Sweden)

    José Fernando Amaral Meletti

    2003-09-01

    ção significativa em M6; o lactato apresentou elevações a partir de M5 e M6. CONCLUSÕES: Considerou-se que a pressão arterial média, freqüência cardíaca, pressão venosa central e pressão capilar pulmonar não refletem o real estado volêmico dos cães no nosso modelo experimental e que o transporte, consumo e a taxa de extração de oxigênio são parâmetros úteis na determinação da reversibilidade e prognóstico do choque hemorrágico.JUSTIFICATIVA Y OBJETIVOS: Diversos modelos experimentales han sido utilizados para ilustrar las alteraciones hemodinámicas y metabólicas que ocurren durante el choque hemorrágico. El objetivo de la pesquisa es el de observar los comportamientos hemodinámicos y metabólicos que suceden en un modelo de sucesión y progresivo de choque hemorrágico en el can, confirmando cuales son los índices que se alteran más precozmente. MÉTODO: El estudio fue realizado en 13 canes bajo anestesia venosa total con pentobarbital sódico, en normoventilación y previamente esplenectomizados. Los animales no fueron hidratados y la velocidad del sangramiento fue dictada por la presión arterial en que el animal se encontraba. Los atributos estudiados fueron divididos en hemodinámicos (frecuencia cardíaca - FC, presión arterial media - PAM, índice de resistencia vascular sistémica - IRVS, índice sistólico - IS, índice cardíaco - IC, índice de choque - I.choque, índice de trabajo sistólico del ventrículo izquierdo - ITSVE, presión capilar pulmonar - PCP, presión venosa central - PVC y metabólicos (saturación venosa mista - SvO2, presión venosa de oxígeno - PvO2, transporte de oxígeno - DO2, consumo de oxígeno - VO2, extracción de oxígeno - TEO2, lactato sérico. La colecta de datos y los atributos fueron estudiados en 6 momentos distintos, siendo M, el momento control y los otros momentos correspondientes a decrécimos gradativos de 10% de la volemia calculada para cada animal. RESULTADOS: La hemorragia determinó diminuci

  4. 利用帕尔贴效应的冷暖型空调床设计及实验分析%Experimental Study of Bed Zoning Air-Conditioner by Using Semiconductor Thermoelectric Effect

    Institute of Scientific and Technical Information of China (English)

    周敬雯; 邓帅; 代彦军; 王如竹

    2012-01-01

    本文基于帕尔贴效应设计了一种冷暖型床体局部空调,简称空调床。空调床由床头制冷装置和床尾供暖装置构成,使床内形成“头凉脚暖”的温度分布。冬季开启供暖模式,可使床内温度达到22°C左右,与房间空调相比,节能率约85%,同时使脚部温度比头部温度高约6°C夏季室温低于30°C时,空调床单独运行,使床内温度降低至28°C左右,节能率约80%。当室温大于30°C时,空调床与房间空调联合运行,与房间空调单独运行相比,节能率为约12%。夏季床内脚部温度比头部温度高1.5°C。%A novel bed zoning air-condition, namely bed AC, was developed based on peltier effect. The Bed AC contains two parts, one is a heating unit on the foot part, and another is a cooling unit on the head part, which can realize "warm feet and cool head". In winter, heat unit operated to maintain bed air temperature around 22°C, and its electrical saving rate was 85%, compared with room AC, and foot air temperature was approximately 6°C higher than that of head. In summer, when room temperature was lower than 30°C, cool unit worked to keep bed air temperature around 28°C, and its energy saving rate was about 80%, and head air temperature was nearly 1.5°C lower than that of foot.. When room temperature was higher than 30°C, bed AC needed to cooperate with room AC, and their total energy saving rate was about 12%, compared with only room AC.

  5. Numerical simulation of nuclear pebble bed configurations

    Energy Technology Data Exchange (ETDEWEB)

    Shams, A., E-mail: shams@nrg.eu [Nuclear Research and Consultancy Group (NRG), Petten (Netherlands); Roelofs, F., E-mail: roelofs@nrg.eu [Nuclear Research and Consultancy Group (NRG), Petten (Netherlands); Komen, E.M.J., E-mail: komen@nrg.eu [Nuclear Research and Consultancy Group (NRG), Petten (Netherlands); Baglietto, E., E-mail: emiliob@MIT.EDU [Massachusetts Institute of Technology (MIT) (United States)

    2015-08-15

    Highlights: • Numerical simulations of a single face cubic centred pebble bed are performed. • Wide range of turbulence modelling techniques are used to perform these calculations. • The methods include 1-DNS, 1-LES, 3-Hybrid (RANS/LES) and 3-RANS models, respectively. • The obtained results are extensively compared to provide guidelines for such flow regimes. • These guidelines are used to perform reference LES for a limited sized random pebble bed. - Abstract: High Temperature Reactors (HTRs) are being considered all over the world. An HTR uses helium gas as a coolant, while the moderator function is taken up by graphite. The fuel is embedded in the graphite moderator. A particular inherent safety advantage of HTR designs is that the graphite can withstand very high temperatures, that the fuel inside will stay inside the graphite pebble and cannot escape to the surroundings even in the event of loss of cooling. Generally, the core can be designed using a graphite pebble bed. Some experimental and demonstration reactors have been operated using a pebble bed design. The test reactors have shown safe and efficient operation, however questions have been raised about possible occurrence of local hot spots in the pebble bed which may affect the pebble integrity. Analysis of the fuel integrity requires detailed evaluation of local heat transport phenomena in a pebble bed, and since such phenomena cannot easily be modelled experimentally, numerical simulations are a useful tool. As a part of a European project, named Thermal Hydraulics of Innovative Nuclear Systems (THINS), a benchmarking quasi-direct numerical simulation (q-DNS) of a well-defined pebble bed configuration has been performed. This q-DNS will serve as a reference database in order to evaluate the prediction capabilities of different turbulence modelling approaches. A wide range of numerical simulations based on different available turbulence modelling approaches are performed and compared with

  6. Measuring bed shear stress along vegetated river beds using FST-hemispheres.

    Science.gov (United States)

    Bockelmann-Evans, B N; Davies, R; Falconer, R A

    2008-09-01

    The measurement of the bed shear stress along vegetated river beds is essential for accurately predicting the water level, velocity and solute and sediment transport fluxes in computational hydroenvironmental models. Details are given herein of an experimental and theoretical study to determine the bed boundary shear stress along vegetated river beds introducing a novel field measuring method, namely the FliessWasserStammtisch (FST)-hemispheres. Although investigations have been conducted previously for sedimentary channels using the FST-hemispheres, this preliminary study is thought to be the first time that such hemispheres have been used to investigate the bed shear stresses in vegetated channels. FST-hemispheres were first developed by Statzner and Müller [1989. Standard hemispheres as indicators of flow characteristics in lotic benthos research. Freshwater Biology 21, 445-459] to act as an integrated indicator of the gross hydrodynamic stresses present near the bed. Test and validation data were found to be at least of the same order of magnitude for the stresses predicted from literature for sedimentary channels, with this study establishing the commencement of a database of calibrated FST-hemisphere laboratory data for vegetated channel beds. In a series of experiments, depths ranging from 0.1 to 0.28 m were considered, equating directly to comparable conditions in small rivers or streams. The results of this study provide a basis for enabling the FST-hemispheres to be used to evaluate the boundary shear stress for a wider range of applications in the future, including vegetated river beds.

  7. Decoración experimental de cerámica aplicada al estudio de las técnicas incisas del área del Paraná An Experimental Study Of Ceramic Decoration: Incising Techniques From The Paraná River Region

    Directory of Open Access Journals (Sweden)

    Flavia V. Ottalagano

    2010-12-01

    Full Text Available Se presentan las experiencias realizadas en torno a la reproducción de técnicas decorativas incisas -de surco rítmico y de punto-, las cuales se registran ampliamente en la cerámica arqueológica del río Paraná. Mediante un enfoque experimental se pretende generar información con respecto a la relación entre las improntas arqueológicas y los posibles gestos técnicos implicados e instrumental empleado por las poblaciones humanas pretéritas. Los trabajos experimentales sobre técnicas incisas son escasos a nivel regional, ya que se advierte un mayor énfasis en cuestiones que hacen a la manufacturación de los recipientes más que a su decoración. Se considera que los aportes ofrecidos por la línea experimental pueden ser aprovechables en el marco de temas de estudio más amplios que involucren, por ejemplo, la dimensión social de los grupos adaptados a este ambiente fluvial durante el Holoceno tardío. Los resultados arribados señalan semejanzas entre las improntas arqueológicas y aquellas realizadas experimentalmente con bordes de cerámica, dientes de nutria, plumas y fragmentos de huesos largos. Estos elementos se encontrarían entre los más idóneos para desarrollar improntas claras, precisas y con buena visibilidad, algunos de los cuales demandarían un determinado cúmulo de habilidades, práctica y conocimientos para su adecuado manejo.This article presents the results of experimental efforts to reproduce techniques of incised ceramic decoration -rhythmic-groove and point- in order to produce markings similar to those that are commonly found on archaeological ceramics from the Paraná River region, Argentina. This experimental approach was used to obtain information regarding the relationship between the archaeological decorations and the possible manual techniques and tools employed by past human populations. Previous experimental work regarding incised techniques is scarce in this region, since a much greater emphasis

  8. Geomechanics of bedded salt

    Energy Technology Data Exchange (ETDEWEB)

    Serata, S.; Milnor, S.W.

    1979-06-08

    Creep data from the literature search is reinterpreted by SGI, resulting in a better understanding of the temperature and stress state dependence of the octahedral creep rate and the octahedral shear strength. The concept of a transition strength between the elastic and the plastic states is in agreement with the data. The elastic and rheological properties of salt are described, and a set of constitutive equations is presented. The dependence of material properties on parameters such as temperature is considered. Findings on the permeability of salt are summarized, and the in-situ behavior of openings in bedded salt is described based on extensive engineering experience. A stress measuring system utilizing a finite element computer code is discussed. Geological factors affecting the stability of salt openings are considered, and the Stress Control Technique for designing stable openings in bedded salt formations is explained.

  9. In Situ Erosion Flume (ISEF): determination of bed-shear stress and erosion of a kaolinite bed

    Science.gov (United States)

    Houwing, Erik-Jan; van Rijn, Leo C.

    1998-06-01

    The strength of a cohesive sediment bed is difficult to determine and must be found experimentally from laboratory tests or through in situ field tests. A new in situ erosion instrument, the In situ Erosion Flume (ISEF), has been developed which is a circulating flow system in the vertical plane. The erosion process of sediment particles of the bed in the test section of the ISEF is related to the prevailing bed-shear stress induced by a unidirectional current. The bed-shear stress can be determined from the measured velocity profile in the test section assuming a logarithmic distribution in a vertical direction. The bed-shear stress equation has been calibrated under various conditions characterised by initiation of motion of sand and gravel particles at a flat bed where the bed-shear stresses mobilising the particles are known from the Shields curve. Three reproducibility tests were carried out under laboratory conditions. The bed consisted of kaolinite and was formed by sedimentation in still fresh water. The results of the three tests showed similar values. The erosion of a kaolinite sediment bed is more precisely determined under laboratory conditions by means of the ISEF. The results are compared with data from the literature. The ISEF is a relatively simple instrument for the determination of the strength of (cohesive) sediment beds. The results based on the ISEF measurements represent the minimum shear stress exerted at initiation of erosion of the bed, which will lead to the maximum shear strength of the top layer of the (cohesive) sediment bed.

  10. un estudio comparativo

    Directory of Open Access Journals (Sweden)

    Federico Varona

    2007-01-01

    Full Text Available La comunicación efectiva es uno de los mayores retos que tienen hoy las organizaciones y empresas tanto a nivel nacional como internacional (global. Este artículo presenta los resultados de la investigación realizada por un equipo internacional de investigadores interesados en descubrir y comparar las conductas comunicativas o estilos de comunicación de los empleados finlandeses y mexicanos cuando interactúan con sus superiores. Para ello presentamos: primero, un breve marco teórico del estudio; segundo, la metodología; tercero, los resultados del análisis estadístico comparativo entre los empleados de Finlandia y México; cuarto, las conclusiones generales y su explicación cultural; y quinto, las implicaciones teóricas y prácticas de este estudio con respecto a las competencias comunicativas necesarias para la comunicación efectiva entre empleados y superiores tanto en organizaciones nacionales como internacionales (globales.

  11. Biomecánica del pié diabético: estudio experimental de pacientes con Diabetes Mellitus Tipo I con y sin neuropatía periférica

    OpenAIRE

    2014-01-01

    La prevalencia de pacientes con diabetes mellitus tipo I en España supone del 10 al 15% del total de los pacientes con diabetes. Algunos estudios apoyan la correlación entre alteraciones biomecánicas del pie y el desarrollo neuropático en diabetes. Objetivo Principal: Relacionar las alteraciones biomecánicas del pie con la presencia de neuropatía periférica de miembros inferiores en pacientes con diabetes mellitus tipo 1. Objetivos secundarios: Conocer los patrones de presión plantar, sup...

  12. Torque de desinserción y propiedades fisico-químicas de implantes dentales grabados con ácidos fluorhídrico y nítrico: estudio experimental en perros Beagle

    OpenAIRE

    Martínez González, José María; García Sabán, Francisco; Ferrándiz Bernal, Javier; Gonzalo Lafuente, Juan Carlos; Cano Sánchez, Jorge

    2006-01-01

    Objetivo: Estudiar la composición, características superficiales y respuesta al torque de desinserción de una superficie implantaria tratada inicialmente con ácido fluorhídrico y posterior pasivado con ácidos fluorhídrico y nítrico. Diseño del estudio: En una primera fase, se seleccionaron 12 implantes en los que se estudiaron las características fisico-químicas mediante mediciones de energía dispersa de rayos X (EDS), microscopio electrónico de barrido y análisis de XPS (espectrometría de...

  13. Terapia intravenosa con células mesenquimales en la fase aguda del daño cerebral: estudio experimental en un modelo animal de trauma craneal pediátrico

    OpenAIRE

    Pérez Suárez, Esther

    2014-01-01

    Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Medicina, Departamento de Pediatría. Fecha de lectura: 26-11-2014 Objetivo: Estudiar si la terapia intravenosa con células madre mesenquimales en la fase aguda del daño cerebral, es segura y consigue mejorar la recuperación motora, sensitiva y cognitiva a medio plazo, en ratas jóvenes que sufren un traumatismo craneoencefálico grave. También se realiza estudio de la distribución y supervivencia de estas células...

  14. Biological denitrification in a fluidized bed.

    Science.gov (United States)

    Narjari, N K; Khilar, K C; Mahajan, S P

    1984-12-01

    A fluidized bed biofilm reactor using sand as the carrier particle was employed to study the effects of superficial velocity on the removal of nitrates as well as on the growth of the biofilm. Velocity was found to affect significantly both nitrate removal and biofilm growth. An analysis based on heterogenous catalysis was used to describe the denitrification process. There is good agreement between analysis and experimental measurements for startup and steady-state operating conditions.

  15. Analysis of effective solid stresses in a conical spouted bed

    Directory of Open Access Journals (Sweden)

    CHARBEL A. L. T.

    1999-01-01

    Full Text Available Some applications of spouted beds have been limited by problems with spout stability. In order to overcome these limitations, research should be concentrated on describing the mechanism by which the spout is developed. This work presents a theoretical and experimental study to describe the effective solid stress distribution in the annular region of a conical spouted bed. From experimental observation, the failure state of the bed of particles at the outset of spouting is identified and related to fluid-particle properties and column dimensions. Linear and angular momentum balances for the solid phase are then formulated as a function of the bed failure state. The set of equations obtained is solved using numerical methods, and results regarding stress distribution, stability and spout shape are presented and discussed.

  16. Physicochemical interaction and its influence on deep bed filtration process

    Institute of Scientific and Technical Information of China (English)

    GUO Jin-long; MENG Jun; LI GUI-ping; LUAN Zhao-kun; TANG Hong-xiao

    2004-01-01

    The capillary model was used to analyze the hydraulic conditions in the deep bed filtration process. Thephysicochemical interaction forces between the filter media and suspended particles and their influence on deep bedfiltration process were also studied theoretically. Through the comparison of the hydraulic and physicochemicalforces, the key influencing factors on the filtration process were proposed and investigated. Pilot study of the micro-flocculation deep bed filtration was carried out in the No. 9 Potable Water Treatment Plant of Beijing, and theexperimental results of hydraulic head loss, particle distribution and entrapment were presented. The theoreticalprediction was reasonably consistent with the experimental results under different conditions, which indicated that theregulation and control of micro-flocculation and deep bed filtration could be realized by the evaluation of thephysicochemical interactions. Further theoretical and experimental research should be carried out to investigate theinteraction mechanism and its application in the deep bed filtration and other cases.

  17. Understanding and predicting bed humidity in fluidized bed granulation.

    Science.gov (United States)

    Hu, Xinhui; Cunningham, John; Winstead, Denita

    2008-04-01

    Bed humidity is a critical parameter that needs to be controlled in a fluidized bed granulation to ensure reliability. To predict and control the bed humidity during the fluidized bed granulation process, a simple model based on the mass conservation of moisture was developed. The moisture mass balance model quantitatively simulates the effects of spray rate, binder solution concentration, airflow rate, inlet air temperature, and dew point on the bed humidity. The model was validated by a series of granulations performed in different scale granulators including Glatt GPCG-1, GPCG-15, and GPCG-60. Good agreement was observed between the theoretical prediction and the measured loss on drying (LOD). The model developed in the current work enables us to choose the appropriate parameters for the fluidized bed granulation and can be used as a valuable tool in process scaling-up.

  18. Bed Rest Muscular Atrophy

    Science.gov (United States)

    Greenleaf, John E.

    2000-01-01

    A major debilitating response from prolonged bed rest (BR) is muscle atrophy, defined as a "decrease in size of a part of tissue after full development has been attained: a wasting away of tissue as from disuse, old age, injury or disease". Part of the complicated mechanism for the dizziness, increased body instability, and exaggerated gait in patients who arise immediately after BR may be a result of not only foot pain, but also of muscular atrophy and associated reduction in lower limb strength. Also, there seems to be a close association between muscle atrophy and bone atrophy. A discussion of many facets of the total BR homeostatic syndrome has been published. The old adage that use determines form which promotes function of bone (Wolff's law) also applies to those people exposed to prolonged BR (without exercise training) in whom muscle atrophy is a consistent finding. An extreme case involved a 16-year-old boy who was ordered to bed by his mother in 1932: after 50 years in bed he had "a lily-white frame with limbs as thin as the legs of a ladder-back chair". These findings emphasize the close relationship between muscle atrophy and bone atrophy. In addition to loss of muscle mass during deconditioning, there is a significant loss of muscle strength and a decrease in protein synthesis. Because the decreases in force (strength) are proportionately greater than those in fiber size or muscle cross-sectional area, other contributory factors must be involved; muscle fiber dehydration may be important.

  19. Coal Bed Methane Primer

    Energy Technology Data Exchange (ETDEWEB)

    Dan Arthur; Bruce Langhus; Jon Seekins

    2005-05-25

    During the second half of the 1990's Coal Bed Methane (CBM) production increased dramatically nationwide to represent a significant new source of income and natural gas for many independent and established producers. Matching these soaring production rates during this period was a heightened public awareness of environmental concerns. These concerns left unexplained and under-addressed have created a significant growth in public involvement generating literally thousands of unfocused project comments for various regional NEPA efforts resulting in the delayed development of public and fee lands. The accelerating interest in CBM development coupled to the growth in public involvement has prompted the conceptualization of this project for the development of a CBM Primer. The Primer is designed to serve as a summary document, which introduces and encapsulates information pertinent to the development of Coal Bed Methane (CBM), including focused discussions of coal deposits, methane as a natural formed gas, split mineral estates, development techniques, operational issues, producing methods, applicable regulatory frameworks, land and resource management, mitigation measures, preparation of project plans, data availability, Indian Trust issues and relevant environmental technologies. An important aspect of gaining access to federal, state, tribal, or fee lands involves education of a broad array of stakeholders, including land and mineral owners, regulators, conservationists, tribal governments, special interest groups, and numerous others that could be impacted by the development of coal bed methane. Perhaps the most crucial aspect of successfully developing CBM resources is stakeholder education. Currently, an inconsistent picture of CBM exists. There is a significant lack of understanding on the parts of nearly all stakeholders, including industry, government, special interest groups, and land owners. It is envisioned the Primer would being used by a variety of

  20. ASSESSMENT OF BED-LOAD PREDICTORS BASED ON SAMPLING IN A GRAVEL BED RIVER

    Institute of Scientific and Technical Information of China (English)

    HADDADCHI Arman; OMID Mohammad H.; DEHGHANI Amir A.

    2012-01-01

    Bedload transport in alluvial channels has been extensively studied and different equations based on field and/or experimental data have been proposed.Prediction of bed-load transport rate using different equations results in wide ranges which are not always reliable.In this study,some of the universal bedload predictors were evaluated with measured load by a Helley-Smith sampler in the Node River,a gravel bed fiver in the northeast part of Iran.From 19 sets of data,14 series of data were used to evaluate the bed-load transport equations.The results show that the equations presented by Van Rijn,Meyer-Peter and Mueller,and Ackers and White may adequately predict bedload transport in the range of field data.

  1. 己二胺有机废液在流化床中焚烧的实验研究%Experimental study on incineration of organic hazardous liquid waste containing hexamethylendiamine in fluidized bed

    Institute of Scientific and Technical Information of China (English)

    别如山; 李炳熙; 陆慧林; 杨励丹; 周定

    2001-01-01

    在实验室规模的热态流化床试验台上,进行了含5%己二胺有机废液的焚烧实验研究.在700—900℃范围内,研究温度及空气过剩系数对NOx沿床高的变化规律,以及它们对NOx排放浓度的影响.实验结果表明,沿高度方向上NOx浓度逐渐降低,并且存在NO2浓度大于NO浓度这一有趣现象.在900℃下氧量增加有利于密相区NO、NO2浓度的降低,说明在有氧条件下NH2促进NOx的还原,在不同空气过剩系数下稀相区出口NOx几乎为零,表明900℃是己二胺有机废液焚烧的合适温度.%Experiments were conducted to investigate NOx concentration profiles along bed height and the influences of temperature and excess air on NOx emission in the temperature range from 700℃ to 900℃, when waste water containing 5% hexamethylenediamine incinerated in a bench scale fluidized bed. The results indicate that NOx concentration profiles decrease progressively with bed height and the concentration of NO2 is larger than that of NO along bed height except in the freeboard at 900℃, where NO, NO2 concentrations are zero. Temperature and excess air play significant role on NOx emission. With increasing in temperature the NOx emission decreases very rapidly, and decreases to zero at 900℃. With increasing in excess air, NOx emission increases considerably at 700℃, but it is almost independent of excess air at 800℃, and at 900℃, NOx emission is almost zero indicating that NH2 from NH2(CH2)6NH2 has strong effect on de-NOx.

  2. Experimental Studies and Application of a Composite Fluidized Bed Bottom Ash Cooler%复合式流化床冷渣器的试验研究及工业应用

    Institute of Scientific and Technical Information of China (English)

    曾兵; 卢啸风; 赵鹏; 甘露; 舒茂龙

    2011-01-01

    A novel fluidized bed bottom ash cooler and the main technical characteristics are introduced. Experiments about gas-solid flow characteristics were conducted in a cold test bed. The experiment results show that the separation chamber has a good separation effect on the boiler bottom ash, and the ash flow characteristic is also good. The separation effect has a direct influence on the operation results of the new ash cooler and can be regulated by adjusting the operation and structure parameters. According to the experiment results, the composite fluidized bed bottom ash cooler (CFBAC) has been industrially applied in a 300MW circulating fluidized bed (CFB) unitl The application results show that the CFBAC has a good cooling effect of bottom ash, a well separation effect, an excellent adaptability on particle size and a large discharge capacity over 30 t/h. The CFBAC could be one direction of the future CFB boiler bottom ash cooler.%提出一种新型流化床冷渣器,介绍了其主要技术特点,并对其气固流动特性进行冷态试验研究。试验结果表明,分选仓喷动床结构对锅炉底渣的粗细颗粒分选作用相当明显,灰渣颗粒整体呈“溢流一底流一溢流”方式有较好的流动特性。分选仓分选效果直接决定着该冷渣器的运行效果,可以通过调节运行参数和结构参数来控制。根据试验结果设计的复合式流化床冷渣器已成功应用于某300Mw循环流化床机组冷渣器改造中。工业应用结果表明,该冷渣器具有较好的底渣冷却效果和粗细颗粒分选效果,底渣粒度适应性强,最大出力超过30讹。复合式流化床冷渣器可作为未来大型循环流化床锅炉冷渣器的发展方向之一。

  3. Heat Transfer in a Fixed Bed of Straw Char

    DEFF Research Database (Denmark)

    Fjellerup, Jan Søren; Henriksen, Ulrik Birk; Jensen, Anker

    2003-01-01

    A model for the thermal conductivity of a straw char bed has been developed. The model extends the work of Yagi and Kunii to describe heat transfer in a bed of cylinders, using a relationship between the interparticle distance and the external porosity. To verify the model, thermal conductivity...... the experimental uncertainty over the range of conditions investigated. The heat transfer model was used in a parametric study to evaluate the effect of gas flow rate, particle diameter, porosity, and temperature on the thermal conductivity in a straw char bed....

  4. DRYING OF GRANULAR MATERIALS IN AGITATED FLUIDIZED BED

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An experimental study of the drying characteristics of an agitated fluidized bed dryer is presented and discussed. In the study, the citric acid particles were used as bed material with the diameters ranging from 0.2mm to 1.3mm. The variables affecting apparently the drying rate were found to be the mass flow rate, the inlet air temperature, the rotary speed of agitating mechanism and the particles feed rate. Comparing with other variables considered, mass flow rate was found to have the least important influence on the drying rate. The agitated fluidized bed dryer is suitable to drying agglomerating or sticky materials.

  5. Racing for the Bed

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    No one knows when the people ofMacheng City began to employthe marriage custom of racingfor the bed, once a custom unique to theTujia ethnic minority. It is said that at the end of awedding, bride and bridegroom enter thebridal chamber together and race for thebed. The one who is the first to sit on thebed will be the master of the new familyIt sounds unreasonable, but quite anumber of people believe in it.Therefore, on the wedding night, manybrides and bridegrooms try their best to

  6. Biparticle fluidized bed reactor

    Science.gov (United States)

    Scott, C.D.

    1993-12-14

    A fluidized bed reactor system which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase is described. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves. 3 figures.

  7. Estudio de competencias del teleformador

    OpenAIRE

    Marcelo, Carlos

    2005-01-01

    El Servicio Andaluz de Empleo de la Consejeria de Empleo de la Junta de Andalucia ha realizado un Estudio de Competencias del Teleformador. Este estudio establece un análisis de competencias necesarias para el diseño, desarrollo y gestión de acciones de e-Learning.

  8. Riesgo de perforación en la mucosectomía esofágica con banda: estudio experimental con dos modelos de ligadores Perforation risk in esophageal endoscopic mucosal resection with ligation: an experimental study with two ligator models

    Directory of Open Access Journals (Sweden)

    J. L. Vázquez-Iglesias

    2007-02-01

    Full Text Available Objetivo: en los últimos años se han publicado varios trabajos que encuentran la mucosectomía con banda (MB como un método seguro para el tratamiento de algunos tumores esofágicos, gástricos y colorrectales. Hemos realizado este estudio en animales de experimentación (cerdos para comparar la seguridad de la MB en esófago, con dos modelos de ligadores multibanda, ya que muchos centros sólo disponen de estos modelos de ligadores comercializados para la ligadura de varices esofágicas. Métodos: se utilizaron 8 cerdos en los que se realizaron 23 resecciones esofágicas sin inyección previa. Se hicieron 10 resecciones con el modelo Six Shooter Saeed y 13 resecciones con el modelo Speedband Superview Super 7. También se comparó la técnica realizando el corte aleatoriamente por debajo o por encima de la banda. Resultados: se produjeron 5 perforaciones, todas con el modelo Speedband. Del total de casos en los que se utilizó este modelo se perforaron el 38,5% frente a ninguna de las intervenciones con el modelo Six Shooter, lo que alcanzó significación estadística (p = 0,046. No hubo deferencias estadísticamente significativas en la frecuencia de perforación, entre realizar el corte por debajo o por encima de la banda. Conclusiones: MB esofágica realizada con el modelo Speedband sin inyección previa, da lugar a perforación en un porcentaje elevado de casos en el animal de experimentación. Se precisan más estudios para establecer si la inyección previa incrementa la seguridad de la técnica con este modelo de ligador.Objective: endoscopic mucosal resection with ligation (EMRL is considered an efficient, safe method for the treatment of some esophageal, gastric and colorectal tumors. We conducted this study using a porcine model in order to compare the safety of esophageal EMRL with two multiband ligation systems, since many centers only use these ligator models in EMRL (commercialized for varix ligation. Methods: eight pigs were

  9. Estudios farmacológicos y toxicológicos de un extracto acuoso de frutos de Opuntia Dillenii Haw

    OpenAIRE

    Loro Ferrer, Juan Francisco

    2016-01-01

    Programa de Farmacología Experimental y Clínica [ES]El presente trabajo estudia los efectos farmacológicos de un extracto acuoso parcialmente purificado con Sephadez G25 (EAPP) obtenido de los frutos de Opuntia Dillenii Haw. Se realizaron los siguientes estudios farmacológicos: tes de irwin, toxicidad aguda (DL50), estudios de analgesia, estudio de la actividad antiinflamatoria, estudio de la coordinación motora, estudio del tránsito intestinal, estudio bioqu&ia...

  10. 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.

  11. Fluidized Bed Air-to-Air Heat Pump Evaporator Evaluation.

    Science.gov (United States)

    1983-07-01

    Frost formation of air-to-air heat pump evaporator surfaces reduces unit efficiency and restricts application. The use of a fluidized bed heat...exchanger as an air-to- heat pump evaporator was investigated to determine if frost accumulation could be eliminated. Experimental investigations were...evaluated, with no practical solution being developed. The use of a fluidized bed heat exchanger for air-to-air heat pump evaporators was determined not feasible. (Author)

  12. Shock-Induced Flows through Packed Beds: Transient Regimes

    CERN Document Server

    Shtemler, Yuri M; Britan, Alex

    2006-01-01

    The early stage of the transient regimes in the shock-induced flows within solid-packed beds are investigated in the linear longwave and high-frequency approximation. The transient resistance law is refined as the Duhameltime integral that follows from the general concept of dynamic tortuosity and compressibility of the packed beds. A closed-form solution is expected to describe accurately the early stage of the transient regime flow and is in qualitative agreement with available experimental data.

  13. INVESTIGATION OF FUEL CHEMISTRY AND BED PERFORMANCE IN A FLUIDIZED BED BLACK LIQUOR STEAM REFORMER

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Whitty

    2003-12-01

    The University of Utah project ''Investigation of Fuel Chemistry and Bed Performance in a Fluidized Bed Black Liquor Steam Reformer'' (DOE award number DE-FC26-02NT41490) was developed in response to a solicitation for projects to provide technical support for black liquor and biomass gasification. The primary focus of the project is to provide support for a DOE-sponsored demonstration of MTCI's black liquor steam reforming technology at Georgia-Pacific's paper mill in Big Island, Virginia. A more overarching goal is to improve the understanding of phenomena that take place during low temperature black liquor gasification. This is achieved through five complementary technical tasks: (1) construction of a fluidized bed black liquor gasification test system, (2) investigation of bed performance, (3) evaluation of product gas quality, (4) black liquor conversion analysis and modeling and (5) computational modeling of the Big Island gasifier. Four experimental devices have been constructed under this project. The largest facility, which is the heart of the experimental effort, is a pressurized fluidized bed gasification test system. The system is designed to be able to reproduce conditions near the black liquor injectors in the Big Island steam reformer, so the behavior of black liquor pyrolysis and char gasification can be quantified in a representative environment. The gasification test system comprises five subsystems: steam generation and superheating, black liquor feed, fluidized bed reactor, afterburner for syngas combustion and a flue gas cooler/condenser. The three-story system is located at University of Utah's Industrial Combustion and Gasification Research Facility, and all resources there are available to support the research.

  14. Evaluación de la fijación femoral en la reconstrucción del ligamento cruzado anterior. Estudio experimental en modelo cadavérico

    OpenAIRE

    Torres Claramunt, Raúl

    2014-01-01

    Los estudios de esta tesis analizan la fijación femoral de la plastia de isquiotibiales para la reconstrucción del ligamento cruzado anterior. Hasta ahora el concepto de isometría ha sido predominante a la hora de realizar el túnel femoral, de manera en que se intentaba dar la misma tensión a la plastia en todos los grados de flexión de la rodilla. Por esto, el túnel se realizaba alto y profundo en el cóndilo femoral lateral. En los últimos años, la localización de este túnel ha cambiado busc...

  15. A New Solution of the Deep Bed Filtration

    OpenAIRE

    Saatçı, A.M.; Halilsoy, Mustafa

    1987-01-01

    We present a more general solution of the standard deep bed filtration equations which explains the initial improvement of effluent quality as a suspension passes through a porous medium. Our solution gives a good fit to experimental data and predicts the experimental observations. The file in this item is the publisher version (published version) of the article.

  16. Experimental Study on the Weathering Features of Bedding Caves at Mt. Danxiashan%丹霞山顺层洞穴风化特征的试验研究

    Institute of Scientific and Technical Information of China (English)

    彭华; 邱卓炜; 潘志新

    2014-01-01

    This study focuses on the bedding caves developed in the 2nd Member of the Danxia Formation at Danxia Basin. Investigations of differential weathering of red bed rocks were conducted, especially the weath-ering features of soft interlaid rock layers and how this weathering effects the development of the bedding caves. Based on field investigations, three bedding caves were selected as study cases, followed by a collection of rock samples with different lithologies, as well as interlayer ground water samples, for laboratory test and analysis. The data reveals that primary factors for bedding cave formation at Mt. Danxiashan are the different lithological characters of rock layers in the cave wall and the rapid weathering and erosion of soft interlaid rock layers. Soft interlaid rocks between layers generally belong to silty mudstone with high content of clay minerals and argillaceous cements. Due to strong absorbability, high porosity and low compressive strength, these soft rocks are vulnerable to weathering and easily broken into smaller pieces. The overlying and underly-ing rock layers are more resistant sandstones or sandy conglomerates, cemented mainly by calcite and iron ox-ides, with low porosity and higher compressive strength. During the weathering process of rock layers in bed-ding caves, factors that are responsible for the disintegration of rocks include the expansion and contraction of clay minerals, dissolution of calcareous cements, and hydration of iron oxides. However, the dominant factors contributes rock decay vary in different lithotypes. For silty mudstones, the repeated expansion and contraction of clays is a significant cause of weathering. As for the weathering of sandstones and sandy conglomerates, the dissolution of calcareous cements plays a more important role. In addition, the infiltration of acid rainwater can also accelerate the weathering processes by ion displacement with minerals in red bed rocks.%以丹霞盆地丹霞组2段顺层

  17. 移动床生物膜反应器处理极低C/N废水试验研究%Experimental studies of extremely low C/N wastewater treatment with moving bed biofilm reactor

    Institute of Scientific and Technical Information of China (English)

    陈建磊; 戴海平

    2011-01-01

    在常温下采用移动床生物膜反应器处理低C/N比废水.结果显示:在填料填充比为40%、进水氨氮质量浓度为25 mg/L条件下,出水氨氮质量浓度基本稳定在4 mg/L左右,氨氮去除率在80%以上,硝化效果突出;进水C/N不足1时,TN及COD去除率分别能达到55%、60%以上,说明移动床生物膜反应器用于处理极低C/N废水具有良好效果.%The extremely low C/N wastewater is treated with moving bed biofilm reactor at the normal temperature. The results show that: With the 40% filling proportion of the packing and about 25 mg/L ammonia nitrogen of the influent, the ammonia nitrogen of the effluent water is stably 4 mg/L, and the removal efficiency of the ammonia nitrogen is above 80%, the nitrification effect is prominent; while the C/N of influent is below 1 the removal rate of TN and COD can reach over 55%, and 60% respectively. These facts show that the moving bed biofilm reactor plays a good role in dealing with the extremely low C/N wastewater.

  18. Influence of bed material size heterogeneity on bedload transport uncertainty

    Science.gov (United States)

    Chen, Li; Stone, Mark C.

    2008-01-01

    The bed material grain size distribution of gravel bed streams is often spatially heterogeneous. The heterogeneity is actually a random parameter, even for a "well-mixed mixture," which potentially causes the transport rate for a given bed material to become an uncertain variable. The cause of bed material heterogeneity is the nonuniformity of the bed material, which is analyzed in this paper using examples from field observations and experimental data. The Monte Carlo simulation method is applied to study the uncertainty of the bedload transport rate using Wilcock's experimental data (P. R. Wilcock et al., 2001; P. R. Wilcock and J. C. Crowe, 2003). Each realization of the Monte Carlo simulation employed a randomly generated grain size distribution field for the entire simulation domain. With sufficient realizations the simulation results were adequate to show that the transport rates were a random variable and the mean transport rates did not fall on a single-valued curve when the local heterogeneity was taken into account. The results indicate that the bedload transport rate of nonuniform sediment has an intrinsic uncertainty that can result solely from the bed material. The results also partially account for the scatter of the fractional transport rate within Wilcock's experimental data. This study presents an important concept in understanding the uncertainty associated with estimates of sediment transport.

  19. 张河湾电站垫层料变形模量试验研究%Experimental Study on Deformation Modulus of Bedding Materials in Zhanghewan Pumped-Storage Power Station

    Institute of Scientific and Technical Information of China (English)

    邹武; 包磊; 刘琼; 陈建飞

    2011-01-01

    Deformation modulus is an important indicator to measure the mechanical properties of geotechnical engineering. After excavating the reservoir slope on Hebei Zhanghewan Pumped-Storage Power Station,all weathered sandstone outcropped a lot, bedrock cracked and jointly developed, which made a big impact on the stability of asphalt concrete panel and reservoir bank base. By testing the particle size distribution, density,moisture content, penetration and deformation modulus of the filled bedding materials for ditch dam No. 5 of the reservoir on Zhanghewan Pumped-storage Power Station, we have checked the carrying and deformation resisting capacity of bedding materials,futher understood their stress-strain characteristics and thus provided a scientific basis for the analysis of safety and stability of the dam bedding materials.%变形模量是衡量岩土工程力学特性的一个重要指标,现场压板荷载试验计算变形模量是最直接有效的方法.河北张河湾抽水蓄能电站上水库边坡施工开挖后全强风化细砂岩出露较多,基岩裂隙和节理发育,对沥青混凝土面板和库岸基础的稳定性影响较大,通过对张河湾抽水蓄能电站上水库5号沟坝体填筑垫层料的颗粒级配、密度及含水率、渗透和变形模量的试验研究,校核了垫层料的承载能力及抵抗变形的能力,了解垫层料的应力位移特性,从而为坝体垫层料的安全稳定分析提供科学依据.

  20. Variability of bed drag on cohesive beds under wave action

    Science.gov (United States)

    Safak, Ilgar

    2016-01-01

    Drag force at the bed acting on water flow is a major control on water circulation and sediment transport. Bed drag has been thoroughly studied in sandy waters, but less so in muddy coastal waters. The variation of bed drag on a muddy shelf is investigated here using field observations of currents, waves, and sediment concentration collected during moderate wind and wave events. To estimate bottom shear stress and the bed drag coefficient, an indirect empirical method of logarithmic fitting to current velocity profiles (log-law), a bottom boundary layer model for combined wave-current flow, and a direct method that uses turbulent fluctuations of velocity are used. The overestimation by the log-law is significantly reduced by taking turbulence suppression due to sediment-induced stratification into account. The best agreement between the model and the direct estimates is obtained by using a hydraulic roughness of 10  m in the model. Direct estimate of bed drag on the muddy bed is found to have a decreasing trend with increasing current speed, and is estimated to be around 0.0025 in conditions where wave-induced flow is relatively weak. Bed drag shows an increase (up to fourfold) with increasing wave energy. These findings can be used to test the bed drag parameterizations in hydrodynamic and sediment transport models and the skills of these models in predicting flows in muddy environments.

  1. Variability of Bed Drag on Cohesive Beds under Wave Action

    Directory of Open Access Journals (Sweden)

    Ilgar Safak

    2016-04-01

    Full Text Available Drag force at the bed acting on water flow is a major control on water circulation and sediment transport. Bed drag has been thoroughly studied in sandy waters, but less so in muddy coastal waters. The variation of bed drag on a muddy shelf is investigated here using field observations of currents, waves, and sediment concentration collected during moderate wind and wave events. To estimate bottom shear stress and the bed drag coefficient, an indirect empirical method of logarithmic fitting to current velocity profiles (log-law, a bottom boundary layer model for combined wave-current flow, and a direct method that uses turbulent fluctuations of velocity are used. The overestimation by the log-law is significantly reduced by taking turbulence suppression due to sediment-induced stratification into account. The best agreement between the model and the direct estimates is obtained by using a hydraulic roughness of 10 - 4 m in the model. Direct estimate of bed drag on the muddy bed is found to have a decreasing trend with increasing current speed, and is estimated to be around 0.0025 in conditions where wave-induced flow is relatively weak. Bed drag shows an increase (up to fourfold with increasing wave energy. These findings can be used to test the bed drag parameterizations in hydrodynamic and sediment transport models and the skills of these models in predicting flows in muddy environments.

  2. 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.

  3. 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.

  4. ESTUDIO DE SECUENCIAS DE TALLA LÍTICA A TRAVÉS DE MODELOS EXPERIMENTALES EN ROCAS SILÍCEAS DEL CENTRO DE ARGENTINA (Study of lithic carving sequences through experimental models in siliceous rocks of central Argentina

    Directory of Open Access Journals (Sweden)

    Eduardo Pautassi

    2012-10-01

    Full Text Available La evidencia arqueológica dejada por los grupos humanos que habitaron el centro de Argentina (provincias de Córdoba y San Luis, desde las primeras ocupaciones hasta momentos previos a la conquista española, pone de manifiesto que estas poblaciones desarrollaron diversas estrategias y adaptaciones a lo largo del tiempo. Una de estas estrategias es la producción de artefactos líticos. En este trabajo, se aborda el estudio de las secuencias de reducción de clastos y de manufactura de bifaces experimentales aplicando la metodología de análisis «no tipológico» para el estudio de los desechos de talla. Estas experiencias fueron realizadas como resultado del análisis de la tecnología lítica de sitios arqueológicos ubicados en la localidad arqueológica de Estancia La Suiza, San Luis. La finalidad de este trabajo es comparar ciertos atributos de las lascas producto de la experimentación para diferenciar tipos de actividades de talla. Realizar esta propuesta nos permite presentar en otra oportunidad la comparación con el registro arqueológico, e intentar dilucidar cómo fueron los diferentes momentos en el proceso de talla. ENGLISH: The archaeological evidence left by the humans who occupied the center of Argentina (comprising the present territory of the provinces of Cordoba and San Luis, Argentina, from the earliest settlements until the moments before the Spanish conquest, shows that these populations developed different strategies and adaptations to the environment over time. One such strategy is the production of lithic artifacts. This contribution specifically addresses the study of sequence of cores and reducing manufacturing bifaces by applying the methodology of the “non-typological” analysis to the study of debitage. These experiments were conducted as a result of the analysis of the lithic technology of archaeological sites located at the archaeological locality of Estancia La Suiza, in San Luis province. The purpose of

  5. Experimental evaluation of the effect of a modified port-location mode on the performance of a three-zone simulated moving-bed process for the separation of valine and isoleucine.

    Science.gov (United States)

    Park, Chanhun; Nam, Hee-Geun; Kim, Pung-Ho; Mun, Sungyong

    2014-06-01

    The removal of isoleucine from valine has been a key issue in the stage of valine crystallization, which is the final step in the valine production process in industry. To address this issue, a three-zone simulated moving-bed (SMB) process for the separation of valine and isoleucine has been developed previously. However, the previous process, which was based on a classical port-location mode, had some limitations in throughput and valine product concentration. In this study, a three-zone SMB process based on a modified port-location mode was applied to the separation of valine and isoleucine for the purpose of making a marked improvement in throughput and valine product concentration. Computer simulations and a lab-scale process experiment showed that the modified three-zone SMB for valine separation led to >65% higher throughput and >160% higher valine concentration compared to the previous three-zone SMB for the same separation.

  6. Experimental study of spiral flow generator in liquid-solid horizontal circulating fluidized bed%水平液固循环流化床起旋器的实验研究

    Institute of Scientific and Technical Information of China (English)

    彭培英; 张伟; 刘燕

    2009-01-01

    An experiment was made of the particles distribution of each section of a single-loop solids circulation system in a φ29 mm×4 200 mm cold liquid-solid horizontal circulating fluidized bed test facility. The CCD image measurement and data processing system was used to study the particles distribution at different operating conditions with the spiral flow generator added.The experiment shows that the spiral pipe flow generator arranged in the liquid-solid horizontal circulating fluidized bed can effectively improve the uniform distribution of particles in a certain distance; but as the axial distance increases, the effect of the spiral flow generator weakened. There was a low non-uniform distribution as the guide vane angle and liquid flow rate increased. For the particle with the same diameter, density and initial volume add the larger the solid particles containing the greater rate of non-uniform degrees.%在φ29 mm×4 200 mm流化床装置上,利用CCD图像测量与数据处理系统在线对导流叶片式局部起旋器对水平液固循环流化床内固相颗粒分布特性的影响进行了研究.结果表明:安装局部起旋器后,颗粒分布状况在一定距离内得到明显改善;但随着轴向距离增加,起旋器作用效果减弱.随着导叶包角、液体流速的增加,颗粒固含率不均匀度减小.对于相同直径的颗粒,密度和初始加入量越大,颗粒固含率不均匀度越大.

  7. Aplicación de un modelo experimental de valoración económica del uso y manejo de la flora colombiana. Estudio de caso: Meliaceae y Anacardiaceae

    Directory of Open Access Journals (Sweden)

    Campos Héctor Aníbal

    2006-12-01

    Full Text Available Se proponen un modelo y un indicador de valoración económica como alternativas para valorar el uso y
    manejo de la flora colombiana y se aplican a nueve especies de Meliaceae y Anacardiaceae: Swietenia macrophylla
    King (caoba, Cedrela odorata L. (cedro, Carapa guianensis Aubl. (carapa, andiroba o tangare, Guarea guidonia
    (L. Sleumer (trompillo, Anacardium occidentale L. (marañón, Anacardium giganteum Hancock ex Engler (marañón gigante, Spondias mombin L. (hobo, Camnosperma panamense Standl. (sajo y Astronium graveolens Jacq. (diomate o quiebracha. El modelo y el indicador propuestos integran todos los tópicos que se consideraron partícipes del valor económico de las especies en dos grandes aspectos: el biológico y el biocultural y socioeconómico. El indicador produce un valor aproximado de la especie valorando los aspectos contemplados en el modelo a través de cinco componentes: valor actual de uso, valor actual de importancia cultural, valor actual de los productos y servicios, valor potencial de los productos y servicios y estatus de la información. Con su aplicación en el estudio de caso se determinó a Cedrela odorata como la especie más valiosa.

  8. y casos de estudios

    Directory of Open Access Journals (Sweden)

    Esteban Valenzuela Van Treek

    2006-01-01

    latinoamericanas, adentrándose en las problemáticas de la más relevantes, así como reflexionar sobre el presente de ellas, tomando para esto algunos casos de estudio.. “En el caso de las áreas metropolitanas, la concentración y el crecimiento de las grandes ciudades con fenómenos de nuevas barriadas, de municipios limítrofes y de ciudades dormitorios, dentro o fuera del término de la gran ciudad, demandan soluciones administrativas de conjunto que superen los esquemas municipales tradicionales” (Barrero, 1993. Esto lleva a definir el problema de estudio de como la aglomeración de población en áreas superiores a las ciudades tradicionales en América Latina, constituyen formas diferentes a los planos nacionales y municipales, por lo que urge crear condiciones para el bienestar de sus ciudadanos. Es necesario para esto, el comprender el sistema político de manera dinámica y variable, el cual esta íntimamente ligado a la constitución a la deriva estructural de las sociedades, pero sobretodo al gobierno de la ciudad, elemento fundante de la civilización occidental en la cual estamos situados.

  9. Fluidized bed combustion of pesticide-manufacture liquid wastes

    Directory of Open Access Journals (Sweden)

    SAŠA MILETIĆ

    2010-04-01

    Full Text Available Industrial liquid wastes can be in the form of solutions, suspensions, sludges, scums or waste oil and have organic properties. The objective of this work was to demonstrate the technical feasibility of a fluidized bed as a clean technology for burning liquid waste from a pesticide production plant. The combustion of liquid waste mixtures, obtained from realistic samples, was investigated in a pilot scale fluidized bed with quartz sand particles of 0.63–1.25 mm in diameter and 2610 kg/m3 in density at 800–950 °C. To ensure complete combustion of liquid waste and additional fuel, the combustion chamber was supplied with excess air and the U/UmF (at ambient temperature was in between 1.1 and 2.3. In the fluidized bed chamber, liquid waste, additional liquid fuel and air can be brought into intense contact sufficient to permit combustion in bed without backfire problems. The experimental results show that the fluidized bed furnace offers excellent thermal uniformity and temperature control. The results of the combustion tests showed that degradation of liquid wastes can be successfully realized in a fluidized bed with no harmful gaseous emissions by ensuring that the temperatures of both the bed and the freeboard are not lower than 900 °C.

  10. Estudio del CH interestelar

    Science.gov (United States)

    Olano, C.; Lemarchand, G.; Sanz, A. J.; Bava, J. A.

    El objetivo principal de este proyecto consiste en el estudio de la distribución y abundancia del CH en nubes interestelares a través de la observación de las líneas hiperfinas del CH en 3,3 GHz. El CH es una molécula de amplia distribución en el espacio interestelar y una de las pocas especies que han sido observadas tanto con técnicas de radio como ópticas. Desde el punto de vista tecnológico se ha desarrollado un cabezal de receptor que permitirá la realización de observaciones polarimétricas en la frecuencia de 3,3 GHz, con una temperatura del sistema de 60 K y un ancho de banda de 140 MHz, y que será instalado en el foco primario de la antena parabólica del IAR. El cabezal del receptor es capaz de detectar señales polarizadas, separando las componentes de polarización circular derecha e izquierda. Para tal fin el cabezal consta de dos ramas receptoras que amplificarán la señal y la trasladarán a una frecuencia más baja (frecuencia intermedia), permitiendo de esa forma un mejor transporte de la señal a la sala de control para su posterior procesamiento. El receptor además de tener características polarimétricas, podrá ser usado en el continuo y en la línea, utilizando las ventajas observacionales y de procesamiento de señal que actualmente posee el IAR.

  11. MEXCODE* CASO DE ESTUDIO

    Directory of Open Access Journals (Sweden)

    Gabriel Arturo García Gómez

    2000-01-01

    Full Text Available El caso plantea la reactivación de un proyecto que se presentó en el año 1995 como alternativa para el desarrollo del centro del Valle y mejora de la eficiencia en el manejo del comercio exterior de la Cuenca Pacífica. El proyecto se revivió a raíz de la necesidad de la compañía patrocinadora de mejorar sus flujos de caja proyectados y la reciente autorización para su funcionamiento. El proyecto es el popularmente denominado “Puerto Seco” de la ciudad de Guadalajara de Buga, internamente nombrado Mexcode. Los estudios iniciales estaban encaminados a que el proyecto fuera manejado por el municipio de Buga, sin embargo, posteriormente se vio la necesidad de buscar que pasara a manos de la empresa privada. El municipio, después de analizar las propuestas de varios inversionistas de la región en las cuales se evaluaba la ubicación dentro de la zona de los predios de sus empresas, su área, proximidad a la línea férrea y a la doble calzada Buga-Tuluá (sitio de paso del 80% de la carga de importación y exportación por Buenaventura y evaluar aspectos relativos a su trayectoria empresarial y compromiso con el desarrollo de la región, decidió otorgarle el proyecto al Grupo Empresarial Agri-Supplies S.A.

  12. 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

  13. Rehydration ratio of fluid bed-dried vegetables

    Indian Academy of Sciences (India)

    Z Bobić; I Bauman; D Ćurić

    2002-06-01

    Fluid-bed drying of vegetable pieces has been investigated. The vegetables used have been potatoes, parsley roots, celery roots and carrots of various dimensions. Starting water content was: potatoes 78%, parsley roots 85.1%, celery roots 93.6%, and carrots 88.6%. Temperatures of fluidisation have varied from 60° to 100°C at velocities of 0.71 ms-1. The goal has been to obtain dry vegetables with 6% to 10% water content and of good rehydration quality. Experimental data (bed height, gas temperature and velocity, pressure drop over the bed, drying time) have been measured and relevant values have been calculated. The results have shown that drying of vegetables in a fluidized bed produces dry vegetable pieces of excellent quality in a much shorter time than in continuous belt-dryers which are generally used.

  14. Limestone fragmentation and attrition during fluidized bed oxyfiring

    Energy Technology Data Exchange (ETDEWEB)

    Fabrizio Scala; Piero Salatino [Istituto di Ricerche sulla Combustione - CNR, Napoli (Italy)

    2010-04-15

    Attrition/fragmentation of limestone under simulated fluidized bed oxyfiring conditions was investigated by means of an experimental protocol that had been previously developed for characterization of attrition/fragmentation of sorbents in air-blown atmospheric fluidized bed combustors. The protocol was based on the use of different and mutually complementary techniques. The extent and pattern of attrition by surface wear in the dense phase of a fluidized bed were assessed in experiments carried out with a bench scale fluidized bed combustor under simulated oxyfiring conditions. Sorbent samples generated during simulated oxyfiring tests were further characterized from the standpoint of fragmentation upon high velocity impact by means of a purposely designed particle impactor. Results showed that under calcination-hindered conditions attrition and fragmentation patterns are much different from those occurring under air-blown atmospheric combustion conditions. Noteworthy, attrition/fragmentation enhanced particle sulfation by continuously regenerating the exposed particle surface. 13 refs., 8 figs.

  15. Analysis of the fluid-bed stability of FCC catalysts at high temperature in terms of bed elasticity

    Institute of Scientific and Technical Information of China (English)

    Paola Lettieri; Luca Mazzer

    2008-01-01

    The effect of temperature on the fluid-bed stability of three FCC catalysts has been analyzed through considerations on fluid-bed elasticity. Experimental findings on the effect of temperature on the elasticity modulus at minimum bubbling conditions, (E)mb, were analyzed using the hydrodynamic fluid-bed stability model developed by Foscolo and Gibilaro (1984) and adopting the interparticle-forces-based stability criterion developed by Mutsers and Rietema (1977). For both models, the parameters which control changes in (E)mb with temperature are discussed, in order to establish the origin of the fluid-bed elasticity and analyze the ability of these models to discriminate between the relative importance of the hydrodynamic and interparticle forces on the stability of the fluidized catalysts.

  16. Thermal degradation of PMMA in fluidised beds.

    Science.gov (United States)

    Smolders, K; Baeyens, J

    2004-01-01

    In recent years, the production and consumption of plastics have increased significantly and wastes are commonly incinerated or dumped in a landfill. Plastics pyrolysis, on the other hand, may provide an alternative means for disposal of plastic wastes with recovery of valuable gasoline-range hydrocarbons or the monomer. Pyrolysis of polymethyl methacrylate (PMMA) may result in very high recycling rates (90-98%) of the monomer methylmethacrylate (MMA) since the cracking of MMA to lighter molecules (CO2, CO and light hydrocarbons) is limited. The MMA-yield is mainly dependent on the residence time of the gas in the reactor and to a lesser extent on the operating temperature. The paper presents experimental work performed in a lead bath and in a fluidised bed. At low temperatures, the reaction is kinetically controlled, whereas at high temperatures, heat transfer restricts the overall reaction rate. It was demonstrated that the heat transfer in the fluid bed could be estimated by the equation of Kothari. A design procedure for a fluid bed PMMA-depolymerisation reactor is outlined and illustrated for a process of 1 tpd PMMA.

  17. 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.

  18. The influence of fine char particles burnout on bed agglomeration during the fluidized bed combustion of a biomass fuel

    Energy Technology Data Exchange (ETDEWEB)

    Scala, Fabrizio; Chirone, Riccardo [Istituto di Ricerche sulla Combustione, CNR, P.le V. Tecchio, 80-80125 Naples (Italy); Salatino, Piero [Dipartimento di Ingegneria Chimica, Universita degli Studi di Napoli Federico II, P.le V. Tecchio, 80-80125 Naples (Italy)

    2003-11-15

    The combustion of biomass char in a bubbling fluidized bed is hereby addressed, with specific reference to the influence that the combustion of fine char particles may exert on ash deposition and bed agglomeration phenomena. Experiments of steady fluidized bed combustion (FBC) of powdered biomass were carried out with the aim of mimicking the postcombustion of attrited char fines generated in the fluidized bed combustion of coarse char. Experimental results showed that the char elutriation rate is much smaller than expected on the basis of the average size of the biomass powder and of the carbon loading in the combustor. Samples of bed material collected after prolonged operation of the combustor were characterized by scanning electron microscopy (SEM)-EDX analysis and revealed the formation of relatively coarse sand-ash-carbon aggregates. The phenomenology is consistent with the establishment of a char phase attached to the bed material as a consequence of adhesion of char fines onto the sand particles. Combustion under sound-assisted fluidization conditions was also tested. As expected, enhancement of fines adhesion on bed material and further reduction of the elutriation rate were observed. Experimental results are interpreted in the light of a simple model which accounts for elutriation of free fines, adhesion of free fines onto bed material and detachment of attached fines by attrition of char-sand aggregates. Combustion of both free and attached char fines is considered. The parameters of the model are assessed on the basis of the measured carbon loadings and elutriation rates. Model computations are directed to estimate the effective size and the peak temperature of char-sand aggregates. The theoretical estimates of the effective aggregate size match fairly well those observed in the experiments.

  19. Experimental study of the drying in dense fluidized beds of a synthetic mud coated with support particulates; Etude experimentale du sechage en lit fluidise dense d'une boue synthetique enrobee sur des particules supports

    Energy Technology Data Exchange (ETDEWEB)

    Gode, C.; Shakourzadeh, K. [Universite de Technologie de Compiegne, L.G.P.I., 60 (France)

    2001-07-01

    This article presents the results of an experimental study of a new drying process for muddy materials and based on the fluidization technique. The granular phase has been obtained by the coating with mud of a porous mineral support, inert and recyclable in the process. Activated porous particulates of alumina (2-5 mm) have been chosen because of their heat transfer properties. A first part of the experimental study concerns the drying process. The second part concerns the attrition and elutriation mechanisms. The experimental measurements have been performed with a laboratory fluidized column (internal diameter = 150 mm) and with a fluidized column (internal diameter = 400 mm) from a semi-industrial facility. The air velocity and the drying temperature are the main adjustment parameters. The working temperatures have been fixed between 20 and 150 deg. C. (J.S.)

  20. The experimental study on new type baking-free brick prepared the circulating fluidized bed boiler (CFBB) ash%循环流化床锅炉灰渣制备新型免烧砖的试验研究

    Institute of Scientific and Technical Information of China (English)

    黄鑫; 夏举佩; 周新涛

    2014-01-01

    本文以循环流化床锅炉(C FBB )灰渣为主要原料,通过实验获得了其制备免烧砖的最佳工艺配料为:石灰7%、飞灰43%、底渣30%、骨料瓜子石20%。通过蒸汽养护和自然养护对比,发现在低石灰掺量时,自然养护效果明显低于蒸汽养护,但随着石灰用量的增加,二者差异逐渐缩小,当高于7%时,检测结果基本一致,在此基础上,通过扩大性工业试验,采用自然养护方式,可生产标号为150的免烧砖砌块。%In this paper ,circulating fluidized bed boiler (CFBB) ash is used as the main raw material for preparing baking free brick to obtain through experiment the optimal ingredients as follows :7% lime ,43%fly ash ,30% bottom ash ,20% aggregate of oval stone .By steam curing and natural curing contrast ,we find that the effect of nature curing is significantly lower than the steam curing .But with the increasing of lime dosage ,the difference is gradually reduced .When lime dosage is higher than 7% ,the test results are basically consistent .On this basis ,unburned block labeled 150 can be produced using natural curing method through the expansion of industrial test .

  1. Experimental investigation and mathematical modelling of the combustion of brown coal, refuse and mixed fuels in a circulating fluidized bed combustor; Experimentelle Untersuchung und mathematische Modellierung der Verbrennung von Braunkohle, Abfallstoffen und Mischbrennstoffen in einer zirkulierenden Wirbelschichtfeuerung

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, W.; Brunne, T.; Hiller, A. [Technische Univ. Dresden (Germany). Inst. fuer Energietechnik; Albrecht, J. [Lurgi Umwelt GmbH, Frankfurt am Main (Germany); Quang, N. [Polytechnic Inst., Danang (Viet Nam)

    1998-09-01

    Extensive experiments on combustion of biological materials and residues in fluidized bed combustors and dust combustors have been carried out at the Department of Power Plant Engineering of Dresden University since the early nineties. Particular interest was taken in mixing brown coal with sewage sludge, sugar pulp and waste wood. The experiments were supplemented by modelling in a research project funded jointly by the BMBF and Messrs. Lurgi since early 1997. A combustion cell model designed by Siegen University is being modified for the new mixed fuels, and preliminary investigations were carried out on a batch reactor while the modelling work was continued. (orig.) [Deutsch] An dem Lehrstuhl fuer Kraftwerkstechnik der TU Dresden werden seit Anfang der 90-iger Jahre umfangreiche experimentelle Untersuchungen zur Verbrennung von Bio- und Reststoffen in Wirbelschicht- und Staubfeuerungen durchgefuehrt. Dabei war vor allem die Zufeuerung dieser Stoffe in Waermeerzeugeranlagen auf Braunkohlenbasis von besonderem Interesse. Experimentell konnte nachgewiesen werden, dass sowohl Biobrennstoffe als auch Abfaelle in zirkulierenden Wirbelschichtfeuerungen umweltschonend zur Waermeerzeugung eingesetzt werden koennen. Als Beispiel wird das an Hand von Braunkohle-Klaerschlammgemischen sowie Bagasse- und Holz-Braunkohlegemischen gezeigt. Neben den experimentellen Untersuchungen bietet die Modellierung der Verbrennungsvorgaenge ein geeignetes Mittel um Voraussagen zu anderen Mischungsanteilen sowie anderen geometrischen Abmessungen machen zu koennen. Seit Anfang 1997 wird dazu ein vom BMBF und der Firma Lurgi gefoerdertes Forschungsvorhaben bearbeitet. Ein von der Universitaet Gesamthochschule Siegen fuer die Braunkohleverbrennung konzipiertes Zellenmodell wird auf die neuen Brennstoffgemische erweitert. Da grundsaetzlich andere Stoffzusammensetzungen vorliegen, wurden an einem Batch-Reaktor Voruntersuchungen zum Pyrolyseverhalten der Brennstoffe durchgefuehrt. Erste

  2. Estudios longitudinales: concepto y particularidades

    Directory of Open Access Journals (Sweden)

    Miguel Delgado Rodríguez

    2004-01-01

    Full Text Available En la presente revisión se analiza el concepto de estudio longitudinal. Los libros de texto de epidemiología actuales en general no lo definen, mientras que sí lo hacen los tratados de estadística. Se habla más de «datos longitudinales» que de «estudios longitudinales». El estudio longitudinal implica la existencia de medidas repetidas (más de dos a lo largo de un seguimiento. Sería pues un subtipo de estudio de cohortes que, a diferencia de los de tipo tabla de vida, permite inferencias a nivel individual y analizar cambios en diferentes variables (exposiciones y efectos y transiciones entre diferentes estados de salud. Las particularidades de este tipo de diseño hace que se tenga que prestar atención especial al control de calidad durante su ejecución, a los abandonos durante el seguimiento, y a los datos perdidos en algunas de las mediciones. El análisis debe tener en cuenta las medidas repetidas y esto es lo que confiere finalmente a un estudio su carácter longitudinal.

  3. How to Find Bed Bugs

    Science.gov (United States)

    ... strap of old box spring covering that is housing adults, skin castings, feces, and eggs. (Photo courtesy ... Bed bugs can survive and remain active at temperatures as low as 7°C (46°F), but they die ...

  4. Torsion testing of bed joints

    DEFF Research Database (Denmark)

    Hansen, Klavs Feilberg; Pedersen, Carsten Mørk

    2008-01-01

    This paper describes a simple test method for determining the torsion strength of a single bed joint between two bricks and presents results from testing using this test method. The setup for the torsion test is well defined, require minimal preparation of the test specimen and the test can...... be carried out directly in a normal testing machine. The torsion strength is believed to be the most important parameter in out-of-plane resistance of masonry walls subjected to bending about an axis perpendicular to the bed joints. The paper also contains a few test results from bending of small walls about...... an axis perpendicular to the bed joints, which indicate the close connection between these results and results from torsion tests. These characteristics make the torsion strength well suited to act as substitute parameter for the bending strength of masonry about an axis perpendicular to the bed joints....

  5. Bed Bugs: The Australian Response

    Directory of Open Access Journals (Sweden)

    Richard C. Russell

    2011-04-01

    Full Text Available Australia has experienced a sudden and unexpected resurgence in bed bug infestations from both Cimex lectularius L. and Cimex hemipterus F. A survey in 2006 revealed that infestations had increased across the nation by an average of 4,500% since the start of the decade. In response, a multi-disciplinary approach to combat the rise of this public health pest was implemented and involved the coordinated efforts of several organizations. The key components of the strategy included the introduction of a pest management standard ‘A Code of Practice for the Control of Bed Bug Infestations in Australia’ that defines and promotes ‘best practice’ in bed bug eradication, the development of a policy and procedural guide for accommodation providers, education of stakeholders in best management practices, and research. These strategies continue to evolve with developments that lead to improvements in ‘best practice’ while bed bugs remain problematic in Australia.

  6. Getting Rid of Bed Bugs

    Science.gov (United States)

    Jump to main content US EPA United States Environmental Protection Agency Search Search Bed Bugs Share Facebook Twitter ... integrated pest management. Preparing for control is very important whether you are considering hiring a professional or ...

  7. Top Ten Bed Bug Tips

    Science.gov (United States)

    ... temperatures are necessary for successful heat treatment. Black plastic bags in the sun might work to kill bed ... Place the used bag in a tightly sealed plastic bag and in an outside garbage bin. 10. Turn ...

  8. Sea bed mapping and inspection

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    The conference has 24 presentations on the topics: Sea bed mapping, inspection, positioning, hydrography, marine archaeology, remote operation vehicles and computerized simulation technologies, oil field activities and plans, technological experiences and problems. (tk)

  9. Bedømmelsens kompleksitet

    Directory of Open Access Journals (Sweden)

    Elsa Schmidt

    2006-03-01

    Full Text Available I artiklen sammenholdes hverdagens bedømmelser af mennesker med de bedømmelser, der sker ved eksaminer. Der er forskelle på grund af det retlige grundlag, men også ligheder. Konkrete erfaringer med klage- og ankesager gennem 8 år fra faget psykologi på landsplan opsummeres. Nogle få praktiske løsninger beskrives.

  10. Inducción experimental de epididimitis en ovinos por inoculación intrauretral con Actinobacillus seminis: estudio bacteriológico, serológico e histopatológico

    OpenAIRE

    Jorge Acosta Dibarrat; Efrén Díaz Aparicio; Beatriz Arellano Reynoso; Víctor Rubén Tenorio Gutiérrez; Jorge Tórtora Pérez

    2006-01-01

    Con el objetivo de inducir la infección experimental de A. seminis, se utilizaron 18 corderos de seis meses de edad: 4 testigos negativos, otros 3 se inocularon con A. seminis vía intraepididimal (IE) y 11 fueron inoculados por vía intrauretral (IU) como sigue: cuatro recibieron factor liberador de gonadotropinas (GnRH) cinco días previos al desafío, cuatro recibieron etilenglicol por vía IE 24 h previas al desafío y tres no recibieron tratamiento previo. De los cuatro testigos negativos, dos...

  11. un objeto de estudio emergente

    Directory of Open Access Journals (Sweden)

    Vanesa Aidée Ramírez Vázquez

    2007-01-01

    Full Text Available El interés de este artículo es mostrar, de manera muy general, los textos que la revista Estudios sobre las Culturas Contemporáneas (ESCC ha publicado desde su creación refi eridas al campo de las Tecnologías de Información y Comunicación (TIC. No se incluyen los estudios sobre la radio y la televisión pues se considera que merecen un tratamiento especial como medios masivos de comunicación con mayor tiempo en el escenario social; se centra, en cambio, en los estudios relativos a las computadoras, Internet, videojuegos, celulares, satélites, redes, chat, lo que se ha dado en llamar Nuevas Tecnologías de Información y Comunicación (NTIC.

  12. Dual Fluidized Bed Biomass Gasification

    Energy Technology Data Exchange (ETDEWEB)

    None

    2005-09-30

    The dual fluidized bed reactor is a recirculating system in which one half of the unit operates as a steam pyrolysis device for biomass. The pyrolysis occurs by introducing biomass and steam to a hot fluidized bed of inert material such as coarse sand. Syngas is produced during the pyrolysis and exits the top of the reactor with the steam. A crossover arm, fed by gravity, moves sand and char from the pyrolyzer to the second fluidized bed. This sand bed uses blown air to combust the char. The exit stream from this side of the reactor is carbon dioxide, water and ash. There is a second gravity fed crossover arm to return sand to the pyrolysis side. The recirculating action of the sand and the char is the key to the operation of the dual fluidized bed reactor. The objective of the project was to design and construct a dual fluidized bed prototype reactor from literature information and in discussion with established experts in the field. That would be appropriate in scale and operation to measure the relative performance of the gasification of biomass and low ranked coals to produce a high quality synthesis gas with no dilution from nitrogen or combustion products.

  13. 振动流化床与浸没水平管平均传热特性理论分析与实验研究%Theoretical prediction and experimental investigation on the average heat transfer characteristic between vibrated fluidized beds and horizontal tubes

    Institute of Scientific and Technical Information of China (English)

    朱学军; 邓俊

    2012-01-01

    在二维流化床( 240mm×80mm)中,以平均粒径dp为1.83mm的玻璃珠为物料,研究了振动流化床与浸没水平管间传热规律;考察了流化数、振动频率、床高、水平管管径等因素对平均传热系数的影响.采用自制探头对浸没加热管束和振动流化床层间平均传热系数进行实验测定,利用颗粒团模型,建立了振动流化床层与浸没水平管间平均传热模型,并对平均传热系数的理论预测值与实验测定值进行了比较.结果表明:计算值与实验值吻合较好,误差在±15%范围内.在较高流化数、低振动频率时,实验值处于理论值上方;随着振动频率、管径增大,平均传热系数实验值逐渐趋于理论预测值甚至低于理论预测值.结果可为带浸没水平管的振动流化床设计和研究提供参考.%Experiments using the glass beads with the average diameter dp of 1.83mm was conducted in a two-dimensional vibrated fluidized bed. The average heat transfer laws have been investigated. The effect of the fluidization numbers, vibration frequency, static bed height, and the tube diameter on the average heat transfer coefficient have been analyzed. The average heat transfer coefficients was experimentally investigated with self-made probe. A mathematical model is proposed to predict the average heat transfer coefficients between vibrated flu— idized bed and immersed horizontal tubes based on the particle packets renewal theory. The results show that the values of theoretical prediction are in good agreement with experimental data, and the error is inrange of ±15%. The values of experimental above the theoretical prediction at the higher fluidization numbers and lower vibration frequency. They are consistent with each other and even lower than theoretical prediction with increasing vibration frequency and tube diamete. The results can provide references for future designing and researching on the vibrated fluidized beds with

  14. Estimation of partition, free and specific diffusion coefficients of paclitaxel and taxanes in a fixed bed by moment analysis: experimental, modeling and simulation studies - doi: 10.4025/actascitechnol.v34i1.8060

    Directory of Open Access Journals (Sweden)

    Marco Aurélio Cremasco

    2011-11-01

    Full Text Available Paclitaxel, as known Taxol®, is an important agent in cancer treatment, founded in mixture with many structural analogs, or taxanes, present in natural source or plant tissue culture broth. The adsorption techniques are used in the purification of placlitaxel from that complex mixture, but despite of the strategy it is important to know the basic parameters associated with any process, such as isotherms and mass transfer parameters. In this paper is presented a simple model to estimate these parameters by moment analysis. After to consider linear isotherm for adsorption, the partition coefficient, free and effective diffusion coefficients of paclitaxel and four major components, in a plant tissue culture broth, were estimated from the first and second moments of peaks in pulse-elution chromatograms. The experimental chromatograms at two flow rates are compared with those ones from model, also proposed in this work. The experimental results of free diffusion coefficient are compared with that ones from the Literature.

  15. Nitrification performance and robustness of fixed and moving bed biofilters having identical carrier elements

    DEFF Research Database (Denmark)

    Pedersen, Lars-Flemming; Oosterveld, Remko; Pedersen, Per Bovbjerg

    2015-01-01

    This study compared moving bed (MB) and fixed bed (FB) biofilter performance. The experimental recir-culating aquaculture system had four equal biofilters in parallel. Each of the two replicated FB biofilters(with heavy elements) and the two MB biofilters (with neutral elements) had 200 l carrier...

  16. Mapping bed-level evolution in laboratory flumes by means of structured light

    NARCIS (Netherlands)

    Angel, J.A.; Gorte, B.G.H.; Vargas Luna, A.; Uijttewaal, W.S.J.

    2014-01-01

    Experimental work in river morphology has already become a key factor to assess and analyze physical and numerical models that describe bed-level evolution in channels (Paola et al, 2009). Different techniques could be used to measure bed topography in laboratories ranging from traditional to high-t

  17. Combustion and co-combustion of biomass in a bubbling fluidized bed boiler

    NARCIS (Netherlands)

    Khan, A.A.

    2007-01-01

    This PhD dissertation concerns the study of different aspects of biomass (co)-combustion in small-scale fluidized bed boilers for heat generation. The most renowned gaseous emissions from fluidized bed combustion, namely, CO and NO, are investigated with the help of experimental and theoretical stud

  18. DETERMINATION OF MARGINALLY STABLE ZONE OF GAS-SOLID MAGNETICALLY FLUIDIZED BEDS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The void fluctuation of magnotically fluidized beds was analyzed and their maginally stable zone was determined. The analysis was based on the two-phase model of magnetically fluidized bed and wave theory. The marginally stable zone determined by this paper matches well with the experimental results.

  19. Status Evaluation of Loose of Jig Bed Based on Fuzzy Inference System

    Institute of Scientific and Technical Information of China (English)

    CHENG Jian; GUO Yi-nan; SUN Wei; MU Jun-ying

    2003-01-01

    This paper mainly describes that loose of jig bed affects jig's separation effect, and the corresponding fuzzy rules were built. Using the evaluating index of jig's separation effect--imperfection (I) and total misplaced material (Cz), it evaluates status of loose of jig bed by fuzzy inference system. Experimental simulation and applications in practice prove the method's feasibility.

  20. Biofluid process: fluidised-bed gasification of biomass

    Energy Technology Data Exchange (ETDEWEB)

    Dittrich, A. [ATEKO a.s., Hradec Kralove (Czech Republic)

    1996-12-31

    Fluidised-bed gasification of biomass was developed by ATEKO by using long-term experience from coal gasification. An experimental unit was built and a number of tests, first with sawdust gasification, were carried out. A gas combustion engine combined with a power generator was installed and operated in power production. (orig.)

  1. 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...

  2. The Performance of Structured Packings in Trickle-Bed Reactors

    NARCIS (Netherlands)

    Frank, M.J.W.; Kuipers, J.A.M.; Versteeg, G.F.; Swaaij, W.P.M. van

    1999-01-01

    An experimental study was carried out to investigate whether the use of structured packings might improve the mass transfer characteristics and the catalyst effectiveness of a trickle-bed reactor. Therefore, the performances of a structured packing, consisting of KATAPAK elements, and a dumped packi

  3. The performance of structured packings in trickle-bed reactors.

    NARCIS (Netherlands)

    Frank, M.J.W.; Kuipers, J.A.M.; Versteeg, G.F.; Swaaij, van W.P.M.

    1999-01-01

    An experimental study was carried out to investigate whether the use of structured packings might improve the mass transfer characteristics and the catalyst effectiveness of a trickle-bed reactor. Therefore, the performances of a structured packing, consisting of KATAPAK elements, and a dumped packi

  4. Oclusión e isquemia intestinal agudas: Estudio fisiopatológico y efectos del SMS 201-995 sobre las variaciones morfológicas, bioquímicas y de supervivencia en un modelo experimental

    OpenAIRE

    Fuertes Guiró, Ferran

    1996-01-01

    Es planteja la hipòtesi que el SMS 201 o octreotide, derivat actiu de la somatostatina, posseeix efectes beneficiosos sobre l'oclusió i la isquemia intestinal d'aparició aguda, millorant les conseqüències de les alteracions fisiopatológiques i amb això verificar en quin mesura posseeix un determinat efecte terapeutic.Per a això s'ha planificat un estudi experimental que ha comprès una avaluació bioquímico-clínica, morfològica i de supervivència en 6 patologies a través d'un protocol en el qua...

  5. Juan Negrín (1892-1956 ) y la investigación experimental en el Laboratorio de Fisiología de la Junta para Ampliación de Estudios

    OpenAIRE

    1990-01-01

    En el marco del despliegue institucional que vivió la ciencia española durante las tres primeras décadas de nuestro siglo debido a la labor desempeñada por la J.A.E., la investigación experimental en biomedicina ocupó una posición muy preferente, merced a la creación de nuevos laboratorios de Histología normal y patológica, Anatomía microscópica o Serologia y Bacteriología que, junto al Instituto Cajal, elevaron su nivel científico y su prestigio internacional. El Laboratorio de Fisiología Ge...

  6. 49 CFR 236.336 - Locking bed.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Locking bed. 236.336 Section 236.336 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Instructions § 236.336 Locking bed. The various parts of the locking bed, locking bed supports, and tappet...

  7. Measurements of the thermal conductivity of compressed beryllium pebble beds. EDFA reference: TW2-TTBB-007a D4

    Energy Technology Data Exchange (ETDEWEB)

    Reimann, J.; Piazza, G.; Xu, Z. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Inst. fuer Kern- und Energietechnik, Programm Kernfusion; Goraieb, A.; Harsch, H. [Goraieb Versuchstechnik, Karlsruhe (Germany)

    2005-05-01

    For helium cooled pebble bed blankets, the description of the thermal-mechanical interaction between pebble beds and structural material requires the knowledge of the pebble bed thermal conductivity k as a function of temperature T and deformation state (pebble bed strain {epsilon}). In the frame of the EFDA Technology Work Programme TW2-TTBB-007a-D4, the measurements of thermal and mechanical parameters of beryllium pebble beds have been performed in the HECOP facility in the Forschungszentrum Karlsruhe. This report gives a summary of previous work on the thermal conductivity k of beryllium pebble beds, describes the experimental set-up, and presents the new experimental results. The investigated pebble beds, consisting of 1 mm pebbles, are representative for dense pebble beds (vibrated after filling, packing factors of {approx}63.5%). Measurements were performed at bed temperatures between 200 and 650 C and maximum pebble bed deformations up to 3.5%. For this parameter range, two different correlations for the thermal conductivity k as a function of pebble bed deformation {epsilon} and temperature T are proposed. The first one is primarily based on measurements but makes use of the conductivity values for non-deformed pebble beds predicted by the Schluender Bauer Zehner (SBZ) model. (orig.)

  8. STUDY OF HYDRODYNAMICS IN FIXED BED OF COMPOSITE GRANULAR MATERIALS

    Directory of Open Access Journals (Sweden)

    Stelian Petrescu

    2010-12-01

    Full Text Available This study aims at the experimental determination of pressure drop and friction factor at gas flow through fixed beds of granular silica gel, alumina and activated carbon, and establishment of an equation containing a modified friction factor Fm to calculate pressure drop. In order to calculate the modified friction factor, an equation was suggested.The experimental values for pressure drop and friction factor were determined using spherical grains of silica gel, cylindrical grains of alumina and silica gel, alumina and activated carbon impregnated with calcium chloride. By means of the suggested equation, the values of pressure drop in fixed bed were calculated and compared with the experimental values. A good agreement between the predicted and experimental data is noticed.

  9. Importance of fragmentation on the steady state combustion of wood char in a bubbling fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Pinho, Carlos [Universidade do Porto (CEFT/FEUP), Porto (Portugal). Faculdade de Engenharia. Centro de Estudos de Fenomenos de Transporte], E-mail: ctp@fe.up.pt

    2010-07-01

    A simple mathematical model for the analysis of the steady state behavior of a bubbling fluidized bed burner is presented, with the main intention of evaluating the importance of the primary fragmentation of fuel particles on the performance of this type of burners. This model has pedagogical advantages because of its simplicity and easiness of application to the analysis of realistic situations. The model is based upon the classical models used for the study of batch combustion processes in fluidized bed reactors. Experimental data from studies of fluidized bed combustion of portuguese vegetable chars are used to support the analysis of the performance of a 1 m diameter fluidized bed combustor. (author)

  10. Rapid ignition of fluidized bed boiler

    Science.gov (United States)

    Osborn, Liman D.

    1976-12-14

    A fluidized bed boiler is started up by directing into the static bed of inert and carbonaceous granules a downwardly angled burner so that the hot gases cause spouting. Air is introduced into the bed at a rate insufficient to fluidize the entire bed. Three regions are now formed in the bed, a region of lowest gas resistance, a fluidized region and a static region with a mobile region at the interface of the fluidized and static regions. Particles are transferred by the spouting action to form a conical heap with the carbonaceous granules concentrated at the top. The hot burner gases ignite the carbonaceous matter on the top of the bed which becomes distributed in the bed by the spouting action and bed movement. Thereafter the rate of air introduction is increased to fluidize the entire bed, the spouter/burner is shut off, and the entire fluidized bed is ignited.

  11. 循环流化床高浓度富氧燃烧试验研究%Experimental Study on Oxy-fuel Combustion With High Oxygen Concentration in a Circulating Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    谭力; 李诗媛; 李伟; 寿恩广; 吕清刚

    2014-01-01

    In order to investigate the effects of combustion temperature and atmosphere on the combustion stability, CO2 concentration and gaseous pollutants emissions in flue gas, in a 0.1 MW circulating fluidized bed (CFB) oxy-fuel combustion facility, oxy-combustion experiments with Datong coal were carried out at O2/CO2 and O2/ recycled flue gas (RFG) atmosphere with high oxygen concentration. The test results show that when the oxygen concentration of the primary air ranges from 49.6%to 55.2%and that of the secondary air is in the range from 45.3%to 51.7%, the CFB oxy-fuel combustion facility maintains stably at O2/RFG atmosphere. In flue gas, CO2 concentration can reach above 90%, SO2 concentration is 87 to 197 mg/MJ, N2O concentration is 48 to 78 mg/MJ, and NO concentration is only 19 to 44 mg/MJ. Compared with the result of O2/CO2 combustion, the concentration of CO and SO2 increases to a certain degree, while N2O concentration decreases obviously, and NO concentration basically remains the same.%#在0.1 MW循环流化床富氧燃烧试验系统上,进行了大同烟煤在O2/再循环烟气(RFG)和O2/CO2配气下的高浓度富氧燃烧试验,研究燃烧温度和气氛对燃烧稳定性、烟气中CO2浓度和气体污染物排放的影响。研究结果表明,O2/RFG气氛下,在一次风氧气浓度为49.6%~55.2%、二次风氧气浓度为45.3%~51.7%范围内,循环流化床能够稳定运行,烟气中CO2浓度达到90%以上,SO2浓度为87~197 mg/MJ,N2O浓度为48~78 mg/MJ,NO仅为19~44 mg/MJ。与O2/CO2配气燃烧相比,O2/RFG燃烧时除NO浓度基本不变外,CO与SO2浓度均有一定程度的增加,而N2O浓度则明显降低。

  12. Experiments and Modelling of Coal Pyrolysis under Fluidized Bed Conditions

    Institute of Scientific and Technical Information of China (English)

    ZhangYongzhe; XuXiangdong; 等

    1999-01-01

    The pyrolysis behavior of two Chinese coals has been investigated in a laboratory-scale bubbling fluidized bed system in Siegen University,Germany,Experimental equipment and procedure are introduced.The amounts of pyrolysis species of each coal were measured,calcuated and compared.A new method was presented to determine the needed parameters in FG-DVC model with the experimental results instead of other much more complicated experiments.

  13. Effectiveness of Mutual Learning Approach in the Academic Achievement of B.Ed Students in Learning Optional II English

    Science.gov (United States)

    Arulselvi, Evangelin

    2013-01-01

    The present study aims at finding out the effectiveness of Mutual learning approach over the conventional method in learning English optional II among B.Ed students. The randomized pre-test, post test, control group and experimental group design was employed. The B.Ed students of the same college formed the control and experimental groups. Each…

  14. Mathematical simulation of radial heat transfer in packed beds by pseudohomogeneous modeling

    Institute of Scientific and Technical Information of China (English)

    Rodrigo Béttega; Marcos Flávio Pinto Moreira; Ronaldo Guimar(a)es Corrêa; José Teixeira Freire

    2011-01-01

    Uniform flow regime and constant effective thermal conductivity inside packed beds are commonly accepted in the evaluation of the fluid dynamics and heat transfer in such systems. However, several authors have confirmed the presence of an oscillatory velocity profile caused by the effective contribution of porosity profile in the fluid dynamic behavior of packed beds, which directly influences the heat transfer inside the beds. This paper describes the application of a pseudo-homogeneous mathematical model for describing heat transfer in packed beds with oscillatory profiles of velocity and porosity, using a radius-dependent model for effective thermal conductivity kr. Several temperature profiles were obtained in a packed bed system with thermal source located on the wall. The simulated temperature and effective thermal conductivity obtained from simulations were compared with experimental data and calculation from a model based on uniform kr fitting. The results indicate that the proposed mathematical modeling was capable of better representing the heat transfer in the packed bed.

  15. Insights in hydrodynamics of bubbling fluidized beds at elevated pressure by DEM-CFD approach

    Institute of Scientific and Technical Information of China (English)

    Zahra Mansourpour; Sedighe Karimi; Reza Zarghami; Navid Mostoufi; Rahmat Sotudeh-Gharebagh

    2010-01-01

    A numerical simulation was conducted to study the effect of pressure on bubble dynamics in a gas-solid fluidized bed. The gas flow was modeled using the continuum theory and the solid phase, by the dis-crete element method (DEM). To validate the simulation results, calculated local pressure fluctuations were compared with corresponding experimental data of 1-mm polyethylene particles. It was shown that the model successfully predicts the hydrodynamic features of the fluidized bed as observed in the experiments. Influence of pressure on bubble rise characteristics such as bubble rise path, bubble sta-bility, average bubbles diameter and bubble velocity through the bed was investigated. The simulation results are in conformity with current hydrodynamic theories and concepts for fluidized beds at high pressures. The results show further that elevated pressure reduces bubble growth, velocity and stability and enhances bubble gyration through the bed, leading to change in bed flow structure.

  16. Magnetically stabilized bed dust filters-Analysis through variable length scale approach

    Institute of Scientific and Technical Information of China (English)

    Jordan Hristov

    2007-01-01

    Magnetically stabilized beds are packed beds subjected to fluid-driven deformation and controlled by magnetically induced interparticle forces.This paper deals with magnetically stabilized beds as deformable porous media and describes their application in dust filtration. The Richardson-Zaki scaling law, U/Ut = εn describes the field controlled bed expansion via the exponent n, that yields a porosity-dependent flow length scale dc =dpεn.The paper addresses two issues: (i) deformation characteristics by assuming homogeneous bed expansion and a definition of bed variable flow length scale; (ii) dust filtration characteristics such as filter coefficient, specific deposit and filtration efficiency expressed in terms of the variable flow length scale and illustrated by experimental data.

  17. Effect of 2 Bedding Materials on Ammonia Levels in Individually Ventilated Cages.

    Science.gov (United States)

    Koontz, Jason M; Kumsher, David M; Kelly, Richard; Stallings, Jonathan D

    2016-01-01

    This study sought to identify an optimal rodent bedding and cage-change interval to establish standard procedures for the IVC in our rodent vivarium. Disposable cages were prefilled with either corncob or α-cellulose bedding and were used to house 2 adult Sprague-Dawley rats (experimental condition) or contained no animals (control). Rats were observed and intracage ammonia levels measured daily for 21 d. Intracage ammonia accumulation became significant by day 8 in experimental cages containing α-cellulose bedding, whereas experimental cages containing corncob bedding did not reach detectable levels of ammonia until day 14. In all 3 experimental cages containing α-cellulose, ammonia exceeded 100 ppm (our maximum acceptable limit) by day 11. Two experimental corncob cages required changing at days 16 and 17, whereas the remaining cage containing corncob bedding lasted the entire 21 d without reaching the 100-ppm ammonia threshold. These data suggests that corncob bedding provides nearly twice the service life of α-cellulose bedding in the IVC system.

  18. Effect of 2 Bedding Materials on Ammonia Levels in Individually Ventilated Cages

    Science.gov (United States)

    Koontz, Jason M; Kumsher, David M; III, Richard Kelly; Stallings, Jonathan D

    2016-01-01

    This study sought to identify an optimal rodent bedding and cage-change interval to establish standard procedures for the IVC in our rodent vivarium. Disposable cages were prefilled with either corncob or α-cellulose bedding and were used to house 2 adult Sprague–Dawley rats (experimental condition) or contained no animals (control). Rats were observed and intracage ammonia levels measured daily for 21 d. Intracage ammonia accumulation became significant by day 8 in experimental cages containing α-cellulose bedding, whereas experimental cages containing corncob bedding did not reach detectable levels of ammonia until day 14. In all 3 experimental cages containing α-cellulose, ammonia exceeded 100 ppm (our maximum acceptable limit) by day 11. Two experimental corncob cages required changing at days 16 and 17, whereas the remaining cage containing corncob bedding lasted the entire 21 d without reaching the 100-ppm ammonia threshold. These data suggests that corncob bedding provides nearly twice the service life of α-cellulose bedding in the IVC system. PMID:26817976

  19. Erosion of heat exchanger tubes in fluidized beds. Annual report, 1990

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, E.K.; Flemmer, R.L.C.

    1991-01-01

    This final report describes the activities of the 3-year project entitled ``Erosion of Heat Exchanger Tubes In Fluidized Beds.`` which was completed at the end of 1990. Project accomplishments include the collection of a substantial body of wear data In a 24in. {times} 24in. fluidized bed, comparative wear results In a 6in. {times} 6in. fluidized bed, the development of a dragometer and the collection of a comprehensive set of drag force data in the 24in. {times} 24in. bed, Fast Fourier Transform (FFT) analysis of bubble probe data to establish dominant bubble frequencies in the 24in. {times} 24in. bed, the use of a heat flux gauge for measurement of heat transfer coefficients in the 24in. {times} 24in. bed and the modeling of the tube wear in the 24in. {times} 24in. bed. Analysis of the wear data from the 24in. square bed indicates that tube wear increases with increase in superficial velocity, and with increase in tube height. The latter effect is a result of the tubes higher up in the bed seeing greater movement of dense phase than tubes lower down In the bed. In addition, tube wear was found to decrease with increase in particle size, for constant superficial velocity. Three models of tube wear were formulated and provided acceptable prediction of wear when compared with the experimental data.

  20. Dynamics of fine particles in liquid-solid fluidized beds

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    On the basis of the Local Equilibrium Model (LEM), fine particles with large Richardson-Zaki exponent n show, under certain conditions during bed expansion and collapse, different dynamic behavior from particles with small n. For an expansion process there may be a concentration discontinuity propagating upward from the distributor, and, on the contrary, for a collapse process there may be a progressively broadening and upward-propagating continuous transition zone instead of discontinuity. The predictions of the bed height variation and the discontinuity trace have been validated experimentally.

  1. Atmospheric fluidized bed coal combustion research, development and application

    CERN Document Server

    Valk, M

    1994-01-01

    The use of fluidized bed coal combustion technology has been developed in the past decade in The Netherlands with a view to expanding the industrial use of coal as an energy supply. Various research groups from universities, institutes for applied science and from boiler industries participated and contributed to this research area. Comprehensive results of such recent experimentation and development work on atmospheric fluidized bed combustion of coal are covered in this volume. Each chapter, written by an expert, treats one specific subject and gives both the theoretical background as well a

  2. Use of a gas-solid fluidized bed bioreactor for bioaugmentation

    Energy Technology Data Exchange (ETDEWEB)

    Behns, W.; Friedrich, K.; Haida, H. [Magdeburg Univ. (Germany). Inst. fuer Apparate- und Umwelttechnik

    1998-04-01

    Experimental research has shown that microbiological degradation in soils really contaminated with mineral oil hydrocarbons and hexachlorocyclohexane respectively can be accelerated and even intensified by a combined treatment in a fluidized bed bioreactor and subsequently in a remediation heap. (orig.)

  3. Empirical closures for particulate debris bed spreading induced by gas–liquid flow

    Energy Technology Data Exchange (ETDEWEB)

    Basso, S., E-mail: simoneb@kth.se; Konovalenko, A.; Kudinov, P.

    2016-02-15

    Highlights: • Experimental study of the debris bed self-leveling phenomenon. • A scaling approach and a non-dimensional model to describe particle flow rate are proposed. • The model is validated against experiments with particles of different properties and at different gas injection conditions. - Abstract: Efficient removal of decay heat from the nuclear reactor core debris is paramount for termination of severe accident progression. One of the strategies is based on melt fragmentation, quenching and cooling in a deep pool of water under the reactor vessel. Geometrical configuration of the debris bed is among the important factors which determine possibility of removing the decay heat from the debris bed by natural circulation of the coolant. For instance, a tall mound-shape debris bed can be non-coolable, while the same debris can be coolable if spread uniformly. Decay heat generates a significant amount of thermal energy which goes to production of steam inside the debris bed. Two-phase flow escaping through the top layer of the bed becomes a source of mechanical energy which can move the particulate debris along the slope of the bed. The motion of the debris will lead to flattening of the bed. Such process is often called “self-leveling” phenomenon. Spreading of the debris bed by the self-leveling process can take significant time, depending on the initial debris bed configuration and other parameters. There is a competition between the time scales for reaching (i) a coolable configuration of the bed, and (ii) onset of dryout and re-melting of the debris. In the previous work we have demonstrated that the rate of particulate debris spreading is determined by local gas velocity and local slope angle of the bed. In this work we develop a scaling approach and a closure for prediction of debris spreading rate based on generalization of available experimental data. We demonstrate that introduced scaling criteria are universal for particles of different

  4. Comprehensive Mathematical Model for Coal Combustion in a Circulating Fluidized Bed Combustor

    Institute of Scientific and Technical Information of China (English)

    金晓钟; 吕俊复; 杨海瑞; 刘青; 岳光溪; 冯俊凯

    2001-01-01

    Char combustion is on a special reducing condition in the dense bed of a circulating fluidized bedcombustor. Experimental findings were used to develop a comprehensive mathematical model to simulate thehydrodynamic and combustion processes in a circulating fluidized bed combustor. In the model, gas-solidinteraction was used to account for the mass transfer between the bubble phase and the emulsion phase in thedense bed, which contributes to the reducing atmosphere in the dense bed. A core-annular structure wasassumed in the dilute area rather than a one-dimensional model. The submodels were combined to build thecomprehensive model to analyze the combustion in a circulating fluidized bed combustor and the effect ofoperating parameters on the coal combustion. The model predictions agree well with experimental results.

  5. Estudios de investigación experimentales

    OpenAIRE

    Serra Añó, Pilar

    2016-01-01

    En este vídeo se explican las principales características de los estudios de investigación experimentales, en cuanto a diseño y procedimientos. En concreto se consideran los estudios experimentales (ensayos clínicos aleatorizados y no aleatorizados) y los estudios cuasi-experimentales (diseño de series temporales y experimentos cruzados).

  6. Influence of turbulence on bed load sediment transport

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Chua, L.; Cheng, N. S.;

    2003-01-01

    This paper summarizes the results of an experimental study on the influence of an external turbulence field on the bedload sediment transport in an open channel. The external turbulence was generated by: (1) with a horizontal pipe placed halfway through the depth, h; (2) with a series of grids...... correlated with the sediment transport rate. The sediment transport increases markedly with increasing turbulence level.......-bed experiments and the ripple-covered-bed experiments. In the former case, the flow in the presence of the turbulence generator was adjusted so that the mean bed shear stress was the same as in the case without the turbulence generator in order to single out the effect of the external turbulence on the sediment...

  7. Metallic species derived from fluidized bed coal combustion. [59 references

    Energy Technology Data Exchange (ETDEWEB)

    Natusch, D.F.S.; Taylor, D.R.

    1980-01-01

    Samples of fly ash generated by the combustion of Montana Rosebud coal in an experimental 18 inch fluidized bed combustor were collected. The use of a heated cascade impactor permitted collection of size fractionated material that avoided condensation of volatile gases on the particles. Elemental concentration trends were determined as a function of size and temperature and the results compared to published reports for conventional power plants. The behavior of trace metals appears to be substantially different in the two systems due to lower operating temperatures and the addition of limestone to the fluidized bed. Corrosion of the impactor plates was observed at the highest temperature and lowest limestone feed rate sampled during the study. Data from the elemental concentration and leaching studies suggest that corrosion is most likely due to reactions involving sodium sulfate. However, it is concluded that corrosion is less of a potential problem in fluidized-bed systems than in conventional coal-fired systems.

  8. Characteristics of oily sludge combustion in circulating fluidized beds.

    Science.gov (United States)

    Zhou, Lingsheng; Jiang, Xiumin; Liu, Jianguo

    2009-10-15

    Incineration of oily sludge in circulating fluidized beds may be an effective way for its management in some cases. The objective of the present paper is to investigate combustion characteristics of oily sludge, which would be helpful and useful for the design and simulation of a circulating fluidized bed. Firstly, the pyrolysis and combustion of oily sludge were studied through some thermal analyses, which included the thermogravimetric (TG) analysis and the differential thermal analytical (DTA) analysis. It was found that the combustion of oily sludge might be the combustion of its pyrolysis products. Secondly, an experiment for measuring of main components of the volatile from oily sludge pyrolysis was carried out. Some mathematic correlations about the compositions of volatile from oily sludge devolatilization were achieved from the experimental results. Finally, the combustion characteristics of oily sludge was studied in a lab-scale circulating fluidized bed, which could obtain some information about the location of release and combustion of the volatiles.

  9. PARTIAL MATCHING FACE RECOGNITION METHOD FOR REHABILITATION NURSING ROBOTS BEDS

    Directory of Open Access Journals (Sweden)

    Dongmei LIANG

    2015-06-01

    Full Text Available In order to establish face recognition system in rehabilitation nursing robots beds and achieve real-time monitor the patient on the bed. We propose a face recognition method based on partial matching Hu moments which apply for rehabilitation nursing robots beds. Firstly we using Haar classifier to detect human faces automatically in dynamic video frames. Secondly we using Otsu threshold method to extract facial features (eyebrows, eyes, mouth in the face image and its Hu moments. Finally, we using Hu moment feature set to achieve the automatic face recognition. Experimental results show that this method can efficiently identify face in a dynamic video and it has high practical value (the accuracy rate is 91% and the average recognition time is 4.3s.

  10. MODELING NONLINEAR DYNAMICS OF CIRCULATING FLUIDIZED BEDS USING NEURAL NETWORKS

    Institute of Scientific and Technical Information of China (English)

    Wei; Chen; Atsushi; Tsutsumi; Haiyan; Lin; Kentaro; Otawara

    2005-01-01

    In the present work, artificial neural networks (ANNs) were proposed to model nonlinear dynamic behaviors of local voidage fluctuations induced by highly turbulent interactions between the gas and solid phases in circulating fluidized beds. The fluctuations of local voidage were measured by using an optical transmittance probe at various axial and radial positions in a circulating fluidized bed with a riser of 0.10 m in inner diameter and 10 m in height. The ANNs trained with experimental time series were applied to make short-term and long-term predictions of dynamic characteristics in the circulating fluidized bed. An early stop approach was adopted to enhance the long-term prediction capability of ANNs. The performance of the trained ANN was evaluated in terms of time-averaged characteristics, power spectra, cycle number and short-term predictability analysis of time series measured and predicted by the model.

  11. ELECTROSTATIC PHENOMENA IN GAS-SOLIDS FLUIDIZED BEDS

    Institute of Scientific and Technical Information of China (English)

    Hsiaotao T. Bi

    2005-01-01

    Electrostatic charges are generated by particle-wall, particle-particle and particle-gas contacts in gas-solids transport lines and fluidized bed reactors. High particle charge densities can lead to particle agglomeration,particle segregation, fouling of reactor walls and internals, leading to undesirable by-product and premature shut-down of processing equipment. In this paper, the charge generation, dissipation and segregation mechanisms are examined based on literature data and recent experimental findings in our laboratory. The particle-wall contact charging is found to be the dominant charge generation mechanism for gas-solids pneumatic transport lines, while bipolar charging due to intimate particle-particle contact is believed to be the dominant charge generation mechanism in gas fluidized beds. Such a bipolar charging mechanism is also supported by the segregation patterns of charged particles in fluidized beds in which highly charged particles tend to concentrate in the bubble wake and drift region behind rising bubbles.

  12. Fluidized bed drying characteristics and modeling of ginger ( zingiber officinale) slices

    Science.gov (United States)

    Parlak, Nezaket

    2015-08-01

    In this study fluidized bed drying characteristics of ginger have been investigated. The effects of the fluidizing air temperature, velocity, humidity and bed height on the drying performance of ginger slices have been found. The experimental moisture loss data of ginger slices has been fitted to the eight thin layer drying models. Two-term model drying model has shown a better fit to the experimental data with R2 of 0.998 as compared to others.

  13. Investigation on Horizontal Mixing of Particles in Dense Bed in Circulating Fluidized Bed(CFB)

    Institute of Scientific and Technical Information of China (English)

    XiaoPing; YanGuizhang; 等

    1998-01-01

    A two dimensional cold CFB test rig has been established.investigation on horizontal mixing of particles in dense bed has been caried out on this test rig.Miaing model has been used in data reduction,the horizontal mixing coefficients of particles in different experimental conditions and in different structures of dense bed have been obtained and compared.By using dimensional analysis,non-dimensional expression of experimental condition and mixing coefficient have been obtained.

  14. Discrete element modelling of pebble packing in pebble bed reactors

    Energy Technology Data Exchange (ETDEWEB)

    Suikkanen, Heikki, E-mail: heikki.suikkanen@lut.fi; Ritvanen, Jouni, E-mail: jouni.ritvanen@lut.fi; Jalali, Payman, E-mail: payman.jalali@lut.fi; Kyrki-Rajamäki, Riitta, E-mail: riitta.kyrki-rajamaki@lut.fi

    2014-07-01

    Highlights: • A discrete element method code is developed for pebble bed reactor analyses. • Methods are established to extract packing information at various spatial scales. • Packing simulations inside annular core geometry are done varying input parameters. • The restitution coefficient has the strongest effect on the resulting packing density. • Detailed analyses reveal local densification especially near the walls. - Abstract: It is important to understand the packing characteristics and behaviour of the randomly packed pebble bed to further analyse the reactor physical and thermal-hydraulic behaviour and to design a safe and economically feasible pebble bed reactor. The objective of this work was to establish methods to model and analyse the pebble packing in detail to provide useful tools and data for further analyses. Discrete element method (DEM) is a well acknowledged method for analysing granular materials, such as the fuel pebbles in a pebble bed reactor. In this work, a DEM computer code was written specifically for pebble bed analyses. Analysis methods were established to extract data at various spatial scales from the pebble beds resulting from the DEM simulations. A comparison with available experimental data was performed to validate the DEM implementation. To test the code implementation in full-scale reactor calculations, DEM packing simulations were done in annular geometry with 450,000 pebbles. Effects of the initial packing configuration, friction and restitution coefficients and pebble size distribution to the resulting pebble bed were investigated. The packing simulations revealed that from the investigated parameters the restitution coefficient had the largest effect on the resulting average packing density while other parameters had smaller effects. Detailed local packing density analysis of pebble beds with different average densities revealed local variations especially strong in the regions near the walls. The implemented DEM

  15. Experimental Autonomous Vehicle Systems

    DEFF Research Database (Denmark)

    Ravn, Ole; Andersen, Nils Axel

    1998-01-01

    The paper describes the requirements for and a prototype configuration of a software architecture for control of an experimental autonomous vehicle. The test bed nature of the system is emphasised in the choice of architecture making re-configurability, data logging and extendability simple...

  16. Numerical study on hygroscopic material drying in packed bed

    Directory of Open Access Journals (Sweden)

    M. Stakić

    2011-06-01

    Full Text Available The paper addresses numerical simulation for the case of convective drying of hygroscopic material in a packed bed, analyzing agreement between the simulated and the corresponding experimental results. In the simulation model of unsteady simultaneous one-dimensional heat and mass transfer between gas phase and dried material, it is assumed that the gas-solid interface is at thermodynamic equilibrium, while the drying rate of the specific product is calculated by applying the concept of a "drying coefficient". Model validation was done on the basis of the experimental data obtained with potato cubes. The obtained drying kinetics, both experimental and numerical, show that higher gas (drying agent velocities (flow-rates, as well as lower equivalent grain diameters, induce faster drying. This effect is more pronounced for deeper beds, because of the larger amount of wet material to be dried using the same drying agent capacity.

  17. Estudios de visitantes a museos

    Directory of Open Access Journals (Sweden)

    Keilyn Rodríguez Sánchez

    2011-01-01

    Full Text Available Este artículo ofrece un estudio bibliográfico en torno a las investigaciones sobre la relación entre la museografía y sus visitantes. El objetivo central de este documento consiste en elaborar una clasificación de esos estudios en programas de investigación de manera que sirva de punto de partida para la construcción de una pedagogía del Museo. Para este fin, se utiliza la propuesta de Schulman, sobre tipificación de estudios en programas de investigación y, al respecto, se plantean cuatro tipos: investigaciones centradas en lo museográfico, investigaciones centradas en el comportamiento museal, investigaciones centradas en la interacción dispositivo-visitantes y las investigaciones centradas en la evaluación museográfica. Se concluye que los resultados de investigación de estos programas, junto con el conocimiento de las técnicas de diseño y a la teoría educativa, serían la base central de un planteamiento sobre pedagogía museológica.

  18. NUMERICAL SIMULATIONS OF HYDRODYNAMIC BEHAVIORS IN CONICAL SPOUTED BEDS

    Institute of Scientific and Technical Information of China (English)

    Z.; G.; Wang; H.; T.; Bi; C.; J.; Lim

    2006-01-01

    The axial and radial distributions of static pressures and vertical particle velocities of conical spouted beds have been simulated and compared with experimental data. Simulation results show that, among all factors investigated, the Actual Pressure Gradient (the APG term) in conical spouted beds, introduced as the default gravity term plus an empirical axial solid phase source term, has the most significant influence on static pressure profiles, followed by the restitution coefficient and frictional viscosity, while other factors almost have no effect. Apart from the solid bulk viscosity, almost all other factors affect the radial distribution of the axial particle velocity, although the influence of the APG term is less significant. For complex systems such as conical spouted beds where a fluidized spout region and a defluidized annulus region co-exist, the new term introduced in this work can improve the CFD simulation. Furthermore, for other systems with the Actual Pressure Gradient different from either fluidized beds or packed beds, the new approach can also be applied.

  19. Moving Bed Gasification of Low Rank Alaska Coal

    Directory of Open Access Journals (Sweden)

    Mandar Kulkarni

    2012-01-01

    Full Text Available This paper presents process simulation of moving bed gasifier using low rank, subbituminous Usibelli coal from Alaska. All the processes occurring in a moving bed gasifier, drying, devolatilization, gasification, and combustion, are included in this model. The model, developed in Aspen Plus, is used to predict the effect of various operating parameters including pressure, oxygen to coal, and steam to coal ratio on the product gas composition. The results obtained from the simulation were compared with experimental data in the literature. The predicted composition of the product gas was in general agreement with the established results. Carbon conversion increased with increasing oxygen-coal ratio and decreased with increasing steam-coal ratio. Steam to coal ratio and oxygen to coal ratios impacted produced syngas composition, while pressure did not have a large impact on the product syngas composition. A nonslagging moving bed gasifier would have to be limited to an oxygen-coal ratio of 0.26 to operate below the ash softening temperature. Slagging moving bed gasifiers, not limited by operating temperature, could achieve carbon conversion efficiency of 99.5% at oxygen-coal ratio of 0.33. The model is useful for predicting performance of the Usibelli coal in a moving bed gasifier using different operating parameters.

  20. Investigation on Agropellet Combustion in the Fluidized Bed

    Science.gov (United States)

    Isemin, R. L.; Konayahin, V. V.; Kuzmin, S. N.; Zorin, A. T.; Mikhalev, A. V.

    Agricultural wastes (straw, sunflower or millet husk, etc.) are difficult to use as fuel because of low bulk density and relatively big ash content with a low melting point. It is possible to produce agropellets of agricultural wastes which are suggested to combust in a fluidized bed of pellets alone, their char particles and ash. The characteristics of the process of fluidization of agropellets are investigated at room temperature. The experiments on agropellet combustion in a fluidized bed are carried out in an experimental set-up. The results of the experiments have shown that in such a bed the pellets produced of straw and millet husk combust with the same rate as those of wood though the latter contain 8.76 - 19.4 times less ash. The duration of combustion of the same portion of straw pellets in a fluidized bed is 3.74 - 7.01 times less than the duration of combustion of cut straw in a fixed bed. Besides, the movement of agropellets prevents agglomeration and slagging of a boiler furnace.

  1. Laboratory rearing of bed bugs

    Science.gov (United States)

    The resurgence of bed bugs Cimex lectularius L. in the United States and worldwide has resulted in an increase in research by university, government, and industry scientists directed at the biology and control of this blood-sucking pest. A need has subsequently arisen for producing sufficient biolog...

  2. Efeitos do halotano, isoflurano e sevoflurano nas respostas cardiovasculares ao pinçamento aórtico infra-renal: estudo experimental em cães Efectos del halotano, isoflurano y sevoflurano en las respuestas cardiovasculares al pinzamiento aórtico infra-renal: estudio experimental en perros Effects of halothane, isoflurane and sevoflurane on cardiovascular responses to infrarenal aortic cross-clamping: experimental study in dogs

    Directory of Open Access Journals (Sweden)

    Flora Margarida Barra Bisinotto

    2003-08-01

    pinzamiento infra-renal de la aorta abdominal puede producir alteraciones hemodinámicas. El objetivo del estudio fue evaluar los efectos del halotano, isoflurano y sevoflurano sobre la función cardiovascular, en perros sometidos al pinzamiento aórtico infra-renal. MÉTODO: El estudio aleatorio fue realizado en 30 perros, distribuidos en tres grupos, de acuerdo con el anestésico halogenado utilizado durante la anestesia, en concentraciones equipotentes de 0,75 CAM: GH (n=10 - halotano a 0,67%; GI (n=10 - isoflurano a 0,96%; y GS (n=10 - sevoflurano a 1,8%. En todos los animales fue realizada ligadura infra-renal de la aorta, por período de 30 min. Los atributos hemodinámicos fueron estudiados en los momentos: C (Control, Ao15 y Ao 30, respectivamente después de15 y 30 min del pinzamiento aórtico, y DAo y DAo15, respectivamente, inmediatamente y después de15 min del despinzamiento aórtico. RESULTADOS: Durante el pinzamiento aórtico hubo, en todos los grupos, aumento de las presiones arterial media y del átrio derecho, y de los índices cardíaco, sistólico y de trabajo sistólico de los ventrículos derecho e izquierdo. La presión de la arteria pulmonar aumentó en GI y GS y la presión pulmonar ocluida en GH y GI. Después del despinzamiento aórtico, hubo normalización de los atributos que se habían elevado, con excepción de los índices cardíaco y sistólico, que continuaron elevados, acompañados de diminución del índice de resistencia vascular sistémica. No hubo diferencia significante entre los grupos en relación a los atributos estudiados, con excepción de la frecuencia cardíaca que fue siempre menor en GH, en relación a los demás grupos, durante el pinzamiento y despinzamiento aórtico. CONCLUSIONES: En el perro, en las condiciones experimentales empleadas, la inhalación del halotano, isoflurano y sevoflurano en concentraciones equipotentes (0,75 CAM no atenúa las respuestas cardiovasculares al pinzamiento aórtico infra-renal.BACKGROUND AND

  3. Stratum energy of coal-bed gas reservoir and their control on the coal-bed gas reservoir formation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Stratum energy of coal-bed gas reservoir, including coal-radix flexibility energy, groundwater flexibility energy and gas flexibility energy (hereinafter "three energy"), depends on the energy homeostasis system, the core process of which is the effective transfer of energy and the geological selective process. Combining with the mechanics experimentations of coal samples, different flexibility energy has been analyzed and researched quantificationally, and a profound discussion to their controls on the coal-bed gas reservoir formation has been made. It is shown that when gas reservoir is surrounded by edge water and bottom water, the deposited energy in the early phase of forming gas reservoir is mostly coal-radix and gas flexibility energy, but the effect of groundwater flexibility energy increases while water-body increases. The deposited energy in the middle and later phase of forming gas reservoir is mostly gas flexibility energy, which is greater than 80% of all deposited energy. In the whole process, larger groundwater body exerts greater influences on gas accumulation. The paper indicated that higher stratum energy is more propitious to forming coal-bed gas reservoir. And higher coal-radix flexibility energy and gas flexibility energy are more propitious to higher yield of gas reservoirs, while higher groundwater flexibility energy is more propitious to stable yield of gas reservoirs. Therefore, the key to evaluating the coal-bed gas reservoir formation is the stratum energy of coal-bed gas reservoir.

  4. 破溃兔扩张皮瓣的细菌学研究%The experimental study of the bacteriology of the recipient bed of the ruptured expanded flap

    Institute of Scientific and Technical Information of China (English)

    胡守舵; 赵延勇; 蒋海越; 杨庆华; 庄洪兴

    2012-01-01

    Objective To study the bacteriology of the ruptured expanded flap. Methods The New Zealand White rabbits were selected as experimental animals. Firstly,the ruptured expanded flap animal models were made and were randomly classified into four groups, named as A group.B group, C group and D group. The tissues of the flap of each group were divided into six parts from center to edge when taking the rupture as the center. The specimens were taken from these parts. All the specimens were quantificationally examined with Cooney's method and qualitatively examined for gram smear and aerobic and anaerobic cultures. Results The experiment results revealed that: ?with the extension of the rupture time, the length of the inflammatory reaction skin-capsule composite tissue gradually increased.the bacterial number in the flap tissue increased, the significant differences existed between each group (P < 0.05). @ If the rupturetime lasted more than three weeks, the infectious ratio of the floor would increase significantly (17%vs67%;P< 0.05). When the floor infection did exist, bacteria could be found in all parts of the flap. ?lf the floor didn't infect.the bacteria exist within the scope 0.5cm longer than the inflammatory reaction skin-capsule composite tissues. @ the main kind of bacteria was gram-positive bacteria. Conclusions The bacteriology of the flap was changed when the expanded flap was ruptured, more attention should be given in clinic.%目的:研究扩张皮瓣破溃后不同时段及部位的细菌状态.方法:以新西兰大白兔作为实验动 物.首先形成兔扩张皮瓣模型,进而形成破溃的扩张皮瓣模型,并随机分为A、B、C、D破溃时间长短不同的四组.各组的皮瓣组织均以破 口为中心,呈环状由内向外分为6个部分;然后在无菌的环境下分别对这6个部分进行标本采集.采取的标本采用Cooney法进行细菌定 量检查和常规接种、需氧和厌氧培养定性检查.结果:①随着破溃时

  5. Wall and Bed Shear Force in Rectangular Open Channels

    CERN Document Server

    Tavakkol, Sasan

    2016-01-01

    A method is introduced to determine the percentage of the total shear force acting on the walls and bed in rectangular open channels. The proposed method takes both the velocity gradients and secondary currents into account. In the current method the channel cross section is divided into subsections using the bisectors along which there are no secondary flow effects, and isovels orthogonal trajectories along which there is no shear stress. Based on these subsections and assuming the equilibrium between the shear force and gravitational force, the share of the bed and wall from the mean shear force of the flow are calculated. Calculated wall and bed shear forces are in very good agreement with experimental data with an average relative error less than 5%. It is also shown that neglecting the effect of secondary currents and only assuming zero-shear division lines does not yield to acceptable results. The method also provides a possible range for wall and bed shear forces which nicely covers the experimental da...

  6. Packed bed heat storage: Continuum mechanics model and validation

    Science.gov (United States)

    Knödler, Philipp; Dreißigacker, Volker; Zunft, Stefan

    2016-05-01

    Thermal energy storage (TES) systems are key elements for various types of new power plant concepts. As possible cost-effective storage inventory option, packed beds of miscellaneous material come into consideration. However, high technical risks arise due to thermal expansion and shrinking of the packed bed's particles during cyclic thermal operation, possibly leading to material failure. Therefore, suitable tools for designing the heat storage system are mandatory. While particle discrete models offer detailed simulation results, the computing time for large scale applications is inefficient. In contrast, continuous models offer time-efficient simulation results but are in need of effective packed bed parameters. This work focuses on providing insight into some basic methods and tools on how to obtain such parameters and on how they are implemented into a continuum model. In this context, a particle discrete model as well as a test rig for carrying out uniaxial compression tests (UCT) is introduced. Performing of experimental validation tests indicate good agreement with simulated UCT results. In this process, effective parameters required for a continuous packed bed model were identified and used for continuum simulation. This approach is validated by comparing the simulated results with experimental data from another test rig. The presented method significantly simplifies subsequent design studies.

  7. Entrainment, motion, and deposition of coarse particles transported by water over a sloping mobile bed

    Science.gov (United States)

    Heyman, J.; Bohorquez, P.; Ancey, C.

    2016-10-01

    In gravel bed rivers, bed load transport exhibits considerable variability in time and space. Recently, stochastic bed load transport theories have been developed to address the mechanisms and effects of bed load transport fluctuations. Stochastic models involve parameters such as particle diffusivity, entrainment, and deposition rates. The lack of hard information on how these parameters vary with flow conditions is a clear impediment to their application to real-world scenarios. In this paper, we determined the closure equations for the above parameters from laboratory experiments. We focused on shallow supercritical flow on a sloping mobile bed in straight channels, a setting that was representative of flow conditions in mountain rivers. Experiments were run at low sediment transport rates under steady nonuniform flow conditions (i.e., the water discharge was kept constant, but bed forms developed and migrated upstream, making flow nonuniform). Using image processing, we reconstructed particle paths to deduce the particle velocity and its probability distribution, particle diffusivity, and rates of deposition and entrainment. We found that on average, particle acceleration, velocity, and deposition rate were responsive to local flow conditions, whereas entrainment rate depended strongly on local bed activity. Particle diffusivity varied linearly with the depth-averaged flow velocity. The empirical probability distribution of particle velocity was well approximated by a Gaussian distribution when all particle positions were considered together. In contrast, the particles located in close vicinity to the bed had exponentially distributed velocities. Our experimental results provide closure equations for stochastic or deterministic bed load transport models.

  8. [Historical analysis of the hospital bed].

    Science.gov (United States)

    Fajardo-Ortiz, Guillermo; Fajardo-Dolci, Germán

    2010-01-01

    Until now the bed has been the basic physical resource in hospitals. This type of furniture has served to study and treat patients, through out the centuries it has undergone changes in the materials they are made of dimensions, functionality, accessories, aesthetic, and design. The hospital bed history is not well known, there are thousands of documents about the evolution of hospitals, but not enough is known about hospital beds, a link between the past and the present. The medical, anthropological, technological, social, and economic dynamics and knowledge have produced a variety of beds in general and hospital beds in particular. From instinctive, rustic, poor and irregular "sites" that have differed in shape and size they had evolved into ergonomic equipment. The history of the hospital bed reflects the culture, techniques and human thinking. Current hospital beds include several types: for adults, for children, for labor, for intensive therapy, emergency purposes, census and non census beds etc.

  9. Chinese Bedding Technology Standard under Drafting

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    National Home Textile Standardization Technology Committee(NHTSTC)set up its Bedding Branch Committee. This will promote the work of Chinese bedding technology standardization and a symbol that China step up to meet the

  10. Pulling a patient up in bed

    Science.gov (United States)

    Moving a patient in bed ... takes at least 2 people to safely move a patient up in bed. Friction from rubbing can ... A slide sheet is the best way to prevent friction. If you do not have one, you ...

  11. EMERGING TECHNOLOGY BULLETIN: SPOUTED BED REACTOR

    Science.gov (United States)

    The Spouted Bed Reactor (SBR) technology utilizes the unique attributes of the "spouting " fluidization regime, which can provide heat transfer rates comparable to traditional fluid beds, while providing robust circulation of highly heterogeneous solids, concurrent with very agg...

  12. Pulsed atmospheric fluidized bed combustion. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1989-11-01

    In order to verify the technical feasibility of the MTCI Pulsed Atmospheric Fluidized Bed Combustor technology, a laboratory-scale system was designed, built and tested. Important aspects of the operational and performance parameters of the system were established experimentally. A considerable amount of the effort was invested in the initial task of constructing an AFBC that would represent a reasonable baseline against which the performance of the PAFBC could be compared. A summary comparison of the performance and emissions data from the MTCI 2 ft {times} 2 ft facility (AFBC and PAFBC modes) with those from conventional BFBC (taller freeboard and recycle operation) and circulating fluidized bed combustion (CFBC) units is given in Table ES-1. The comparison is for typical high-volatile bituminous coals and sorbents of average reactivity. The values indicated for BFBC and CFBC were based on published information. The AFBC unit that was designed to act as a baseline for the comparison was indeed representative of the larger units even at the smaller scale for which it was designed. The PAFBC mode exhibited superior performance in relation to the AFBC mode. The higher combustion efficiency translates into reduced coal consumption and lower system operating cost; the improvement in sulfur capture implies less sorbent requirement and waste generation and in turn lower operating cost; lower NO{sub x} and CO emissions mean ease of site permitting; and greater steam-generation rate translates into less heat exchange surface area and reduced capital cost. Also, the PAFBC performance generally surpasses those of conventional BFBC, is comparable to CFBC in combustion and NO{sub x} emissions, and is better than CFBC in sulfur capture and CO emissions even at the scaled-down size used for the experimental feasibility tests.

  13. Estudio sobre encofrados de madera modernos

    Directory of Open Access Journals (Sweden)

    de la Peña Aznar, Juan M.

    1980-12-01

    Full Text Available The author continues the development of the subject «Modern Timber Formwork», by summing up the comparative examination —already carried out in Part III of this Study— of the different types of glued timber existing on the market. In addition, the loads and stresses allovk/able for coniferous timber and the proposal for establishing Regulations for the Timber Section of the Research and Experimental Forestry Institute of Spain are given. In part V of the author's Study, published in this article, the important subject of the glues used for joining timber, a truly vital point in order to obtain louvered timber beams which are simply glued together, is approached.

    El autor continúa el desarrollo del tema sobre «Encofrados de madera modernos», resumiendo el estudio comparativo —ya hecho en la Parte III de este Estudio— de las diferentes vigas de madera encolada existentes en el mercado dando, además, las cargas y tensiones admisibles para maderas coníferas y la propuesta de Reglamentación de la Sección de Maderas del Instituto Forestal de Investigaciones y Experiencias de España. En la parte V del Estudio del autor, publicada en este artículo, se aborda el importante tema de las colas empleadas para las uniones de madera, algo realmente vital para la obtención de vigas de madera en celosía simplemente encoladas.

  14. Feasibility study - Lowered bed temperature in Fluidised Bed boilers for waste; Foerstudie - Saenkt baeddtemperatur i FB-pannor foer avfallsfoerbraenning

    Energy Technology Data Exchange (ETDEWEB)

    Niklasson, Fredrik

    2009-01-15

    constant O{sub 2} concentration in the flue gas, the emissions of CO were unaffected by changed ratios of air and recycled flue gas to reduce the bed temperature. However, the emissions of NO{sub x} tended to increase due to raised temperatures of about 40 deg C at the top of the furnace at maximum load. When increasing the amount of recycled flue gas to the bed, the concentration of oxygen is reduced and its implications upon the chemistry in the bed and possible accumulation of unburned fuel have not been investigated due to the short experimental period. Chemical analysis of sand from the bed showed that the concentration of chlorides in the sand increased more that 4 times after 30 hours of operation at reduced bed temperatures. This finding indicates that the chemical balance in the bed is significantly altered when the temperature is reduced. To determine the consequences for the operation of the boiler, further experiments and measurements that are more extensive are necessary. No measurable changes of alkali contents in the sand were observed.

  15. Bed Bug Education for School Maintenance

    Science.gov (United States)

    Henriksen, Missy

    2012-01-01

    Bed bugs are a growing problem, not only in homes and hotels, but also in schools and colleges. Facility administrators and staff need to understand the bed bug resurgence and develop best practices to deal with an infestation. In this article, the author offers tips for preventing and treating bed bugs in school and university settings.

  16. 21 CFR 868.5180 - Rocking bed.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rocking bed. 868.5180 Section 868.5180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5180 Rocking bed. (a) Identification. A rocking bed is a...

  17. Characteristics of fluidized-packed beds

    Science.gov (United States)

    Gabor, J. D.; Mecham, W. J.

    1968-01-01

    Study of fluidized-packed bed includes investigation of heat transfer, solids-gas mixing, and elutriation characteristics. A fluidized-packed bed is a system involving the fluidization of small particles in the voids of a packed bed of larger nonfluidized particles.

  18. Fluidization quality analyzer for fluidized beds

    Science.gov (United States)

    Daw, C. Stuart; Hawk, James A.

    1995-01-01

    A control loop and fluidization quality analyzer for a fluidized bed utilizes time varying pressure drop measurements. A fast-response pressure transducer measures the overall bed pressure drop, or over some segment of the bed, and the pressure drop signal is processed to produce an output voltage which changes with the degree of fluidization turbulence.

  19. Estudios de ingresos municipales: Bolivia

    OpenAIRE

    José Antonio Teran C.

    2007-01-01

    El estudio abarca tres ámbitos de evaluación y recomendaciones: i) el marco normativo que establece las políticas para las administraciones tributarias municipales; ii) las capacidades de estas administraciones y las condiciones de oferta y demanda de servicios de asistencia para su fortalecimiento; y iii) la evaluación cuantitativa de los ingresos propios municipales, el establecimiento de categorías y las políticas que podrían implementarse a partir de esta información.

  20. LOS ESTUDIOS DE POBREZA URBANA

    Directory of Open Access Journals (Sweden)

    Rina De León Herrera

    2007-08-01

    Full Text Available En este artículo se intenta mostrar en forma sucinta la evolución de los estudios de pobreza urbana; se retoma para ello la producción escritural de investigadores que han hecho aportes valiosos sobre la temática en diferentes épocas y espacios geográficos. La información se ha organizado en dos unidades de análisis: la producción escritural en los países desarrollados y en los países en desarrollo.

  1. Review of acute cancer beds.

    LENUS (Irish Health Repository)

    Evans, D S

    2012-01-01

    A review of admissions to cancer services at University Hospital Galway (UHG) was undertaken to assess the appropriateness of hospital usage. All cancer specialty patients admitted from 26-28 May 2009 were reviewed (n = 82). Chi square tests, Exact tests, and One-way ANOVA were utilised to analyse key issues emerging from the data. Fifty (61%) were classified as emergencies. Twenty three (67%) occupied a designated cancer bed with 24 (30%) in outlying non-oncology wards. The mean length of stay was 29.3 days. Possible alternatives to admission were identified for 15 (19%) patients. There was no evidence of discharge planning for 50 (60%) admissions. There is considerable potential to make more appropriate utilisation of UHG for cancer patients, particularly in terms of reducing bed days and length of stay and the proportion of emergency cancer admissions, and further developing integrated systems of discharge planning.

  2. Los estudios longitudinales en la prevención de las enfermedades cardiovasculares

    OpenAIRE

    Ignacio Balaguer Vintró

    2004-01-01

    Los estudios longitudinales de cohortes bien definidas han contribuido a la identificación de los factores de riesgo de la cardiopatía coronaria y otras complicaciones clínicas de la aterosclerosis. Después de comentar las conclusiones de los estudios de la aterosclerosis experimental y los factores de riesgo sugeridos por el estudio de una serie de infartos de miocardio en adultos jóvenes en comparación con controles apareados, se expone la metodología, el desarrollo y l...

  3. THE BAUXITES AND JELAR - BEDS

    Directory of Open Access Journals (Sweden)

    Krešimir Sakač

    1993-12-01

    Full Text Available Minor bauxite deposits and occurrences were formed in technically disturbed environments in the middle part of the Adriatic geotectonic unit in Dinarides, contemporary with the clastic Jelar-beds in the Late Lutetian time. Uneven chemical composition of these Eocene bauxites, their sporadic occurrences in developed paleorelief as well as characteristic petrographic composition of the immediate overlying rocks point out at different genetical conditions (the paper is published in Croatian.

  4. ESTUDIO DEL EFECTO DE LA CRANEOACUPUNTURA EN PACIENTES CON ENFERMEDAD VASCULAR CEREBRAL. (EVC)

    OpenAIRE

    PEREZ BRAVO, MIGUEL

    2009-01-01

    LA ENFERMEDAD VASCULAR CEREBRAL (EVC) EN MEXICO ES UN IMPORTANTE PROBLEMA DE SALUD PUBLICA, ES LA TERCERA CAUSA DE MUERTE Y LA SEGUNDA EN PRODUCIR INCAPACIDAD NEUROLOGICA. EL OBJETIVO DE ESTE ESTUDIO FUE EVALUAR EL EFECTO DE LA CRANEOACUPUNTURA EN PACIENTES CON ENFERMEDAD VASCULAR CEREBRAL (ZHONG FENG). EL PRESENTE ES UN ESTUDIO EXPERIMENTAL, PROSPECTIVO Y LONGITUDINAL, REALIZADO EN EL HOSPITAL DEL ISSSTE DE LA CIUDAD DE PUEBLA, A UN GRUPO DE 11 PACIENTES DE AMBOS SEXOS, CON...

  5. Nitrogen Chemistry in Fluidized Bed Combustion of Coal

    DEFF Research Database (Denmark)

    Jensen, Anker Degn

    The present Ph.D thesis describes an experimental and theoretical investigation of the formation and destruction of nitrogen oxides (NOx and N2O) in fluidized bed combustion (FBC) of coal. A review of the current knowledge of nitrogen chemistry in FBC is presented. The review covers both laboratory...... for the emission of NOx from FBC has been developed as part of a JOULE project. The model is based on the two-phase theory of fluidization for the bed with a Kunii-Levenspiel type freeboard model and includes submodels for coal devolatilization, combustion of volatiles and char and a detailed model of NO formation...... plant were used for model verification. The simulations of the NO emission during staged combustion and NH3 injection for NO reduction were in qualitative agreement with the experimental data. A parametric study of the influence of operating conditions on the conversion of fuel-N to NO showed...

  6. Study of Modeling for Fixed-Bed Adsorption Process and Simulation in Experimental CO Separation Through PSA%固定床吸附分离过程数学模型研究及其在变压吸附CO的应用

    Institute of Scientific and Technical Information of China (English)

    孙暠; 宁平; 陈玉保; 陈云华

    2013-01-01

    变压吸附分离过程以其能耗小和高产率的特点日益受到重视,在提纯分离和资源化利用工业尾气部分成分方面为环境工程所利用.本文针对Skarstrom变压吸附的吸附、解吸循环,在线性驱动力和Langmuir组成的传质动力学模型的基础上建立了较为完整的传质、动量和热量的传输耦合模型.模型以固定床吸附提纯工业尾气中CO为实验背景,对吸附、均压以及解吸实验过程作了模拟.模型提出固定床截面面积函数概念,在轴向一个维度上建立模型.模型含有对固态吸附剂吸附量的量化描述.模型分别对吸附和均压两个阶段做了模拟.解吸过程中床层出口流速直接决定解吸速率,模拟结果与实验一致,模型能够正确刻画变压循环的复杂流态动态过程,比静态活塞流假设更加适用于复杂Skarstrom循环,为理论研究和工艺设计提供有力工具.%The Pressure Swing Adsorption (PSA) process is generally preferable in industrial application including environmental engineering,due to its high productivity and low energy consuming in gas separation.In this paper a math model is developed for Skarstrom Cycling of PSA operation,coupling with the adsorption kinetics composed by Linear Driving Force (LDF) and Langmuir equation.A relatively complete model considering the integration of mass,momentum and heat dynamic transfer is then proposed,then a simulation of adsorption step and pressure equilibrium step in Skarstrom is carried on.The introduction of the section area variable as a function of axial length of the fixed bed helps model this PSA cycling in one dimension in an objective and accurate manner.The absorbed mass amount on solid particle in fixed bed is dynamically depicted in this model.The experimental background of this simulation is a CO separation process via PSA technique from industrial tail gas.In validation,this simulation yields an agreeable numerical result with the testing

  7. Agglomeration-Free Distributor for Fluidized Beds

    Science.gov (United States)

    Ouyang, F.; Sinica, A.; Levenspiel, O.

    1986-01-01

    New gas distributor for fluidized beds prevents hot particles from reacting on it and forming hard crust. In reduction of iron ore in fluidized bed, ore particles do not sinter on distributor and perhaps clog it or otherwise interfere with gas flow. Distributor also relatively cool. In fluidized-bed production of silicon, inflowing silane does not decompose until within bed of hot silicon particles and deposits on them. Plates of spiral distributor arranged to direct incoming gas into spiral flow. Turbulence in flow reduces frequency of contact between fluidized-bed particles and distributor.

  8. The Inlfuence of Feeding Method on Fluidization Behavior of Fixed Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    Ren Shihong; Mao Anguo; Wei Xiaoli

    2014-01-01

    An experimental installation of cold model simulation was set up to study the bed pressure drop in different re-gions of ifxed lfuidized bed reactor during top feeding and bottom feeding, respectively, at various gas velocities with the lfuidization image of solid particles monitored at the same time. By comparing the changes in bed density and operating gas velocity in different regions of ifxed lfuidized bed reactor, the inlfuence of top feeding and bottom feeding patterns on lfuidi-zation behavior could be investigated. The results showed that the bed density in top feeding reactor responded more stably to the change in gas velocity along with the advantage of working in a wider range of operating gas velocities. Based on this study, it is concluded that existing bottom feeding reactor conifgurations cannot meet the lfuidization requirements;and op-timization of bottom feeding reactor will be needed.

  9. The Influence of an Acoustic Field on the Bed Expansion of Fine Particles

    Institute of Scientific and Technical Information of China (English)

    Akash M. Langde; R.L.Sonolikar

    2011-01-01

    Fine particles are difficult to fluidize due to strong interparticle attraction.An attempt has been made to study the bed expansion of silica gel(dp=25μm) powder in presence of an acoustic field.A 135 mm diameter fluidized bed activated by an acoustic field with sound intensity up to 145 dB and frequency from 90 Hz to 170 Hz was studied.The effects of sound pressure level,sound frequency and particle loading on the bed expansion were investigated.Experimental results showed that,bed expansion was good in presence of acoustic field of particular frequency.In addition,it was observed that in presence of acoustic field the bed collapses slowly.

  10. Approximate relationship of coal bed methane and magnetic characteristics of rock via magnetic susceptibility logging

    Science.gov (United States)

    Zhao, Yonghui; Wu, Jiansheng; Zhang, Pingsong; Xiao, Pengfei

    2012-02-01

    In coal bed methane (CBM) exploration, how to improve the accuracy for locating and evaluating the CBM deposits is still a problem due to the rarity of occurrence of CBM. Combined with the distribution of the CBM content in the Huainan coalfield, the approximate relationship between the occurrence of CBM and the magnetic properties of the coal bed and adjacent mudstone have been widely discussed by magnetic logging. Experimental results show that magnetic susceptibility of the coal bed and adjacent mudstone would clearly increase with the CBM content in a coal bed. According to the results of the experiment, the prediction of the CBM content has been accomplished for different coal beds, and the results are consistent with the distribution of the CBM content throughout the whole coalfield. Preliminary data analysis reveals that there is indeed a correlation between the changes of magnetic rock characteristics and the occurrence of the CBM, and this finding may shed some light on the evaluation of CBM.

  11. Focal Gray Matter Plasticity as a Function of Long Duration Head-down Tilt Bed Rest

    Science.gov (United States)

    Koppelmans, V.; DeDios, Y. E.; Wood, S. J.; Reuter-Lorenz, P. A.; Kofman, I.; Bloomberg, J. J.; Mulavara, A. P.; Koppelmans, V.

    2014-01-01

    Long duration spaceflight (i.e., > or = 22 days) has been associated with changes in sensorimotor systems, resulting in difficulties that astronauts experience with posture control, locomotion, and manual control. The microgravity environment is an important causal factor for spaceflight induced sensorimotor changes. Whether these sensorimotor changes may be related to structural and functional brain changes is yet unknown. However, experimental studies revealed changes in the gray matter (GM) of the brain after simulated microgravity. Thus, it is possible that spaceflight may affect brain structure and thereby cognitive functioning and motor behavior. Long duration head-down tilt bed rest has been suggested as an exclusionary analog to study microgravity effects on the sensorimotor system. Bed rest mimics microgravity in body unloading and bodily fluid shifts. In consideration of the health and performance of crewmembers both in- and post-flight, we are conducting a prospective longitudinal 70-day bed rest study as an analog to investigate the effects of microgravity on the brain. VBM analysis revealed a progressive decrease from pre- to in- bed rest in GM volume in bilateral areas including the frontal medial cortex, the insular cortex and the caudate. Over the same time period, there was a progressive increase in GM volume in the cerebellum, occipital-, and parietal cortex, including the precuneus. The majority of these changes did not fully recover during the post-bed rest period. Analysis of lobular GM volumes obtained with BRAINS showed significantly increased volume from pre-bed rest to in-bed rest in GM of the parietal lobe and the third ventricle. Temporal GM volume at 70 days in bed rest was smaller than that at the first pre-bed rest measurement. Trend analysis showed significant positive linear and negative quadratic relationships between parietal GM and time, a positive linear relationship between third ventricle volume and time, and a negative linear

  12. Velocity profiles of turbidity currents flowing over a flat bed

    OpenAIRE

    Kikura, H.; Murakawa, H.; Tasaka, Y.; Chamoun, Sabine; De Cesare, Giovanni; Schleiss, Anton

    2016-01-01

    Turbidity currents are the main source of suspended sediment transport in reservoirs and thus one of the main causes of sedimentation. One of the techniques used to avoid reservoir sedimentation is through venting of turbidity currents. In the framework of a research work on venting, velocity measurements of turbidity currents flowing on a flat bed are carried out using Ultrasonic Velocity Profilers (UVP). Five profilers of 4 MHz placed at different positions in an experimental flume provide ...

  13. Indução anestésica após o tratamento do choque hemorrágico: estudo experimental comparando a cetamina e o etomidato Inducción anestésica después del tratamiento del choque hemorrágico: estudio experimental eomparando la cetamina y el etomidato Anesthetic induction after treated hemorrhagic shock: experimental study comparing ketamine and etomidate

    Directory of Open Access Journals (Sweden)

    Adilson O. Fraga

    2006-08-01

    áveis em todos os grupos. CONCLUSÕES: O etomidato ou a cetamina foram capazes de manter a estabilidade hemodinâmica nos cães que sofreram choque hemorrágico intenso e que foram tratados com NaCl a 0,9% ou NaCl a 7,5%.JUSTIFICATIVA Y OBJETIVOS: El sangramiento que conlleva al choque hemorrágico generalmente necesita un tratamiento quirúrgico bajo anestesia general. A su vez, los anestésicos pueden comprometer más las condiciones hemodinámicas. El objetivo de este estudio fue el de comparar los efectos hemodinámicos de la cetamina y del etomidato durante la inducción anestésica en perros sometidos a un modelo experimental de choque hemorrágico y reanimación. MÉTODO: Treinta y dos perros mestizos fueron sometidos al choque hemorrágico presión-controlada, reanimación e inducción anestésica. Después de alcanzar la presión objeto de 40 mmHg ellos fueron divididos aleatoriamente en dos grupos de acuerdo con el líquido usado en la resucitación: NaCl a 0.9% (32 mL.kg-1 y NaCl a 7,5% (4 mL.kg-1. Después de la infusión de volumen, esos grupos fueron divididos nuevamente de acuerdo con el anestésico utilizado: GI NaCl a 0.9% y cetamina; GII NaCl a 7.5% y cetamina; GIII NaCl a 0.9% y etomidato; y GIV NaCl a 7.5% y etomidato. Mediciones hemodinámicas fueron obtenidas en cinco momentos: (M0 inicial; (M1 después del desarrollo del choque hemorrágico; (M2 después de la administración de soluciones; (M3 5 minutos después de la inducción anestésica; (M4 15 minutos después de la inducción anestésica. Se hizo el análisis estadístico usando el Student t test y two-way ANOVA. Fueron considerados significativos valores de p menores que 0,05. RESULTADOS: Después de la instalación del choque, los dos sueros reestablecieron los estándares hemodinámicos a los valores iniciales. Independiente del anestésico o del solución utilizada, después de la inducción anestésica la presión arterial media permaneció inalterada en todos los grupos. La presi

  14. Equilibrium bed-concentration of nonuniform sediment

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Knowledge of the equilibrium bed-concentration is vital to mathematical modeling of the river-bed deformation associated with suspended load but previous investigations only dealt with the reference concentration of uniform sediment because of difficulties in observation of the bed-concentration. This work is a first attempt to develop a theoretical formula for the equilibrium bed-concentration of any fraction of nonuniform sediment defined at the bed-surface. The formula is based on a stochastic-mechanistic model for the exchange of nonuniform sediment near the bed, and described as a function of incipient motion probability, non-ceasing probability, pick-up probability, and the ratio of the average single-step continuous motion time to static time. Comparison of bed-concentration calculated from the proposed formula with the measured data showed satisfactory agreement, indicating the present formula can be used for solving the differential equation governing the motion of suspended load.

  15. APLICACIÓN DE UNA PROPUESTA TEÓRICA Y METODOLÓGICA PARA LA PRODUCCIÓN DE DOCUMENTOS EN EL MODELO POR COMPETENCIAS: UN ESTUDIO CUASIEXPERIMENTAL (IMPLEMENTATION OF THEORETICAL AND METHODOLOGICAL PROPOSAL TO PRODUCE DOCUMENTS BY THE COMPENTENCY MODEL-QUASI-EXPERIMENTAL RESEARCH

    Directory of Open Access Journals (Sweden)

    Araya Muñoz Ma. Isabel

    2011-04-01

    Full Text Available Resumen:Este artículo muestra los resultados de un estudio cuasiexperimental, definido como Diseño de Grupo Control sin Tratamiento. Se elaboró y se implementó una propuesta teórica y metodológica para el proceso de enseñanza y aprendizaje para la producción de documentos en las oficinas, en el enfoque por competencias, en un curso de las carreras Administración de Oficinas y Educación Comercial de la Escuela de Secretariado Profesional de la Universidad Nacional de Costa Rica, primer ciclo 2009. Tres grupos participaron: uno experimental con tratamiento y dos grupos control con la metodología tradicional. Los resultados del postest mostraron que el experimental superó el promedio de rendimiento en 6,5 puntos al grupo control 2 y en 1,13 puntos al grupo control 1, línea que se marca en la comparación del rendimiento por áreas cognoscitivas. Para complementar los resultados de los tests se exploraron también factores del proceso de enseñanza y de aprendizaje aplicado en cada grupo. Además, mediante técnicas cualitativas se identificó la incidencia en el rendimiento de las estrategias de aprendizaje, el interés de los estudiantes y las estudiantes, su experiencia laboral, la formación dual y la carrera así como el papel de la persona docente. Se concluye que el modelo de formación por competencias podría mejorar el rendimiento académico en la producción de documentos cuando un espacio pedagógico es abordado desde la integración de saberes a partir de actividades didácticas que fomenten el diálogo, la indagación, la aplicación teórica a la resolución de problemas, el aprendizaje experiencial en el aula y en entornos lo más relacionados con la futura práctica profesional.Abstract: This article shows the results of a quasi-experimental study defined as Control Group Design without Treatment. A theoretical and methodological proposal was carried out and implemented for the teaching and learning processes for

  16. A CFD model for biomass combustion in a packed bed furnace

    Science.gov (United States)

    Karim, Md. Rezwanul; Ovi, Ifat Rabbil Qudrat; Naser, Jamal

    2016-07-01

    Climate change has now become an important issue which is affecting environment and people around the world. Global warming is the main reason of climate change which is increasing day by day due to the growing demand of energy in developed countries. Use of renewable energy is now an established technique to decrease the adverse effect of global warming. Biomass is a widely accessible renewable energy source which reduces CO2 emissions for producing thermal energy or electricity. But the combustion of biomass is complex due its large variations and physical structures. Packed bed or fixed bed combustion is the most common method for the energy conversion of biomass. Experimental investigation of packed bed biomass combustion is difficult as the data collection inside the bed is challenging. CFD simulation of these combustion systems can be helpful to investigate different operational conditions and to evaluate the local values inside the investigation area. Available CFD codes can model the gas phase combustion but it can't model the solid phase of biomass conversion. In this work, a complete three-dimensional CFD model is presented for numerical investigation of packed bed biomass combustion. The model describes the solid phase along with the interface between solid and gas phase. It also includes the bed shrinkage due to the continuous movement of the bed during solid fuel combustion. Several variables are employed to represent different parameters of solid mass. Packed bed is considered as a porous bed and User Defined Functions (UDFs) platform is used to introduce solid phase user defined variables in the CFD. Modified standard discrete transfer radiation method (DTRM) is applied to model the radiation heat transfer. Preliminary results of gas phase velocity and pressure drop over packed bed have been shown. The model can be useful for investigation of movement of the packed bed during solid fuel combustion.

  17. Los estudios longitudinales en la prevención de las enfermedades cardiovasculares

    Directory of Open Access Journals (Sweden)

    Ignacio Balaguer Vintró

    2004-01-01

    Full Text Available Los estudios longitudinales de cohortes bien definidas han contribuido a la identificación de los factores de riesgo de la cardiopatía coronaria y otras complicaciones clínicas de la aterosclerosis. Después de comentar las conclusiones de los estudios de la aterosclerosis experimental y los factores de riesgo sugeridos por el estudio de una serie de infartos de miocardio en adultos jóvenes en comparación con controles apareados, se expone la metodología, el desarrollo y los resultados de los estudios longitudinales realizados en Estados Unidos desde 1949: Twin Cities, Framingham, Pooling Project, Western Collaborative, Puerto Rico, Evans County, NI-HONSAN, San Francisco, Harvard, Bogalusa y CARDIA. Se presta especial atención a las hipótesis propuestas al inicio del estudio de Framingham y a los obstáculos y cambios para continuar el proyecto después de los primeros veinticuatro años. A continuación se expone el Seven Countries Study, ideado y dirigido por Ancel Keys y primer estudio realizado con metodología centralizada en varios países, y los estudios longitudinales realizados en diversos países de Europa: Whitehall, Manresa, París, British Regional, Northwick Park, Caerphilly, Speedwell, PROCAM. Se analiza el papel de los estudios longitudinales en la metodología de los estudios posteriores: hijos e hijas de los participantes en Framingham, estudios longitudinales basados en cuestionarios, estudios de otros posibles factores de riesgo, prevalencia de factores de riesgo en estudios retrospectivos, ensayos de intervención primaria (MRFT, WHO European Collaborative Trial y el de Goteburgo y la participación de los equipos entrenados en el Proyecto MONICA. Se señalan los temas todavía en debate en relación con la metodología y los resultados de los estudios longitudinales: exámenes periódicos de los participantes en las cohortes de los estudios epidemiológicos, cambios en la definición de nuevos casos de accidentes

  18. A conceptual framework for shear flow-induced erosion of soft cohesive sediment beds

    Science.gov (United States)

    Winterwerp, J. C.; van Kesteren, W. G. M.; van Prooijen, B.; Jacobs, W.

    2012-10-01

    This paper proposes a conceptual framework for erosion of cohesive sediment beds. We focus on cohesive beds, distinguishing between floc erosion, surface erosion, and mass erosion. By (our) definition, surface erosion is a drained soil mechanical process, whereas mass erosion occurs under undrained conditions. The eroding shear stress is modeled through a probability density function. This yields a continuous description of floc erosion and surface erosion as a function of mean bed shear stress. Furthermore, we assume a distribution for the bed strength. The mean values of the bed strength are derived from soil mechanical theory, assuming that the surface erosion rate is limited by the swelling rate from the undrained shear strength in the bed to its drained value at its surface. The rate of erosion then relates to the undrained shear strength of the soil, and its consolidation (swelling) coefficient. The critical shear stress for erosion is slightly larger than the true cohesion of the bed, i.e., the drained strength, and follows a power law relation with the plasticity index. The conceptual framework proposed herein has been validated against a limited number of experimental data, and has a series of advantages above other methods of direct measuring erodibility, as it is inexpensive and can be used to attain space-covering information on the sediment bed. Moreover, the use of bulk soil mechanical parameters accounts implicitly for the effects of organic material, though the role of, e.g., macrophytobenthos mats and/or bioturbation is difficult to capture a priori.

  19. The heat transfer mechanisms in fluidized beds; Laemmoensiirtomekanismit leijukerroksessa

    Energy Technology Data Exchange (ETDEWEB)

    Fogelholm, C.J.; Blomster, A.M.; Kojola, H. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Energy Technology and Environmental Protection

    1997-10-01

    The goal of the research project is to improve the accuracy of the heat transfer correlation in circulating fluidized beds and to define how the heat transfer is distributed in radiation and convection in the different parts of the fluidized bed. This will be carried out by studying the behaviour and the heat transfer of the fluidized bed in the boundary layer near the wall. During the project the concentration and the velocity of the sand particles are measured. The particle concentration and the particle velocity are measured by an image analysis system. A video camera and a Super VHS recorder are used to capture live images from the bed. The images are digitized and stored on a PC. The measured particle concentration was at highest slightly over 20 % on the straight wall. As expected, the velocity of the fluidizing gas had the most important role on the particle concentration. The experimental studies of the particle velocity were started last autumn 1996. The velocities of the particles were measured by using a multiple exposure technique. Afterwards the images captured were analyzed by performing a Fourier transform analysis. So far the results have been encouraging and the analyzing work will be ended this spring. (orig.)

  20. Adsorption of aromatic amino acids in a fixed bed column

    Directory of Open Access Journals (Sweden)

    M.A. Cremasco

    2003-09-01

    Full Text Available Phenylalanine (Phe and tyrosine (Tyr are two of the twenty amino acids in proteins; they are classified as aromatic amino acids, because both have a benzene ring in their structures. These amino acids are important in the synthesis of several biologically active amines, such as beta-endorphin, a neurotransmitter. Amino acids can be separated by ion-exchange chromatography. In this case, it is important that fixed-bed adsorber design adequately predict the breakthrough curve. This work presents a mathematical model for both fluid and porous phases. In the solution proposed for this model the liquid-phase concentration inside the particles is solved analytically and is related to the liquid-phase concentration in the bed using Duhamel's theorem. The solution for liquid-phase concentration in the bed is then solved numerically instead of analytically. The basic mass transfer parameters are from the literature. The results from the model are compared with those obtained experimentally using Phe and Tyr diluted in aqueous solutions in a fixed bed of PVP (poly-4-vinylpyridine resin.

  1. Forced Convection Heat Transfer in Plate Channels Filled with Packed Beds or Sintered Porous Media

    Institute of Scientific and Technical Information of China (English)

    姜培学; 李勐; 任泽霈

    2002-01-01

    In the present work, forced convection heat transfer in plate channels filled with metallic or non-metallic particles (packed beds) or sintered porous media is simulated numerically using a thermal non-equilibrium model. The numerical simulation results are compared with experimental data. The difference between convection heat transfer in packed beds and in sintered porous media and the effects of the boundary condition assumptions are investigated. The results show that the numerical simulation of convection heat transfer of air or water in packed beds using the local thermal non-equilibrium model and the variable porosity model agrees well with the experimental data. The convection heat transfer coefficient in sintered porous media is much higher than that in packed beds. In the numerical simulation of convection heat transfer in sintered porous media, the boundary conditions on the wall should be that the particle temperatures are equal to the fluid temperature.

  2. Combustion of low grade fractions of Lubnica coal in fluidized bed

    Directory of Open Access Journals (Sweden)

    Mladenović Milica R.

    2012-01-01

    Full Text Available In this paper a method of examination of fuel suitability for fluidized bed combustion is presented. The research of combustion characteristics of low grade fractions of Lubnica brown coal in the fluidized bed by the aforementioned methodology has been carried out on a laboratory semi-industrial apparatus of 200 kWt. Description of the experimental fluidized bed combustion facility is given, as well as experimental results, with the focus on furnace temperature distribution, in order to determine the location of the zone of intensive combustion. Based on investigation results, which are focused on combustion quality (combustion completion as well as on satisfying the environmental protection criteria, it can be stated that the investigated coal is suitable for burning in bubbling, as well as in circulating fluidized bed.

  3. FLUIDIZATION OF FINE POWDERS IN FLUIDIZED BEDS WITH AN UPWARD OR A DOWNWARD AIR JET

    Institute of Scientific and Technical Information of China (English)

    Ruoyu Hong; Jianmin Ding; Hongzhong Li

    2005-01-01

    The hydrodynamic behavior of fine powders in jet-fluidized beds was studied numerically and experimentally. The starting point of numerical simulation was the generalized Navier-Stokes (N-S) equations for the gas and solids phases. The κ-εturbulence model was used for high-speed gas jets in fluidized beds. Computation shows that a suitable turbulence model is necessary to obtain agreement between the simulation and literature experimental data for a high-speed gas jet. The model was applied to simulating the fluidization of fine powders in fluidized beds with an upward or a downward air jet. An empirical cohesion model was obtained by correlating the cohesive force between fine particles using a cohetester. The cohesion model was embedded into the two-fluid model to simulate the fluidization of fine powders in two-dimensional (2-D) beds. To study the fluidization behavior of fine and cohesive powders with a downward jet,experiments were performed in a 2-D bed. Agreement between the computed time-averaged porosity and measured data was obtained. With an upward jet in the bed center, the measured and computed porosities show a dilute central core, especially at very high jet velocities. Based on our experiments and computations, a downward jet located inside the bed is recommended to achieve better mixing and contacting of gas and solids.

  4. The Berlin emissivity database (BED)

    Science.gov (United States)

    Maturilli, A.; Helbert, J.; Moroz, L.

    2008-03-01

    Remote-sensing infrared spectroscopy is the principal field of investigation for planetary surfaces composition. Past, present and future missions to the solar system bodies include in their payload, instruments measuring the emerging radiation in the infrared range. Apart from measuring the reflected radiance, more and more spacecrafts are equipped with instruments measuring directly the emitted radiation from the planetary surface. The emitted radiation is not only a function of the composition of the material but also of its texture and especially the grain size distribution. For the interpretation of the measured data an emissivity spectral library of planetary analogue materials in grain size fractions appropriate for planetary surfaces is needed. The Berlin emissivity database (BED) presented here is focused on relatively fine-grained size separates, providing thereby a realistic basis for the interpretation of thermal emission spectra of planetary regoliths. The BED is therefore complimentary to existing thermal emission libraries, like the ASU library for example. BED currently contains emissivity spectra of plagioclase and potassium feldspars, low Ca and high Ca pyroxenes, olivine, elemental sulfur, Martian analogue minerals and volcanic soils, and a lunar highland soil sample measured in the wavelength range from 7 to 22 μm as a function of particle size. For each sample we measured the spectra of four particle size separates ranging from <25 to 250 μm. The device we used is built at DLR (Berlin) and is coupled to a Fourier-transform infrared spectrometer Bruker IFS 88 purged with dry air and equipped with a nitrogen-cooled MCT detector. All spectra were acquired with a spectral resolution of 4 cm -1. We are currently working on upgrading our emissivity facility. A new spectrometer (Bruker VERTEX 80 V) and new detectors will allow us to measure the emissivity of samples in the wavelength range from 1 to 50 μm in a vacuum environment. This will be

  5. The feedback effect caused by bed load on a turbulent liquid flow

    CERN Document Server

    Franklin, Erick de Moraes; Rosa, Eugênio Spanó

    2016-01-01

    Experiments on the effects due solely to a mobile granular layer on a liquid flow are presented (feedback effect). Nonintrusive measurements were performed in a closed conduit channel of rectangular cross section where grains were transported as bed load by a turbulent water flow. The water velocity profiles were measured over fixed and mobile granular beds of same granulometry by Particle Image Velocimetry. The spatial resolution of the measurements allowed the experimental quantification of the feedback effect. The present findings are of importance for predicting the bed-load transport rate and the pressure drop in activities related to the conveyance of grains.

  6. Prediction of product distribution in fine biomass pyrolysis in fluidized beds based on proximate analysis.

    Science.gov (United States)

    Kim, Sung Won

    2015-01-01

    A predictive model was satisfactorily developed to describe the general trends of product distribution in fluidized beds of lignocellulosic biomass pyrolysis. The model was made of mass balance based on proximate analysis and an empirical relationship with operating parameters including fluidization hydrodynamics. The empirical relationships between product yields and fluidization conditions in fluidized bed pyrolyzers were derived from the data of this study and literature. The gas and char yields showed strong functions of temperature and vapor residence time in the pyrolyzer. The yields showed a good correlation with fluidization variables related with hydrodynamics and bed mixing. The predicted product yields based on the model well accorded well with the experimental data.

  7. Volatiles combustion in fluidized beds. [Quarterly] technical progress report, 4 December 1994--4 March 1995

    Energy Technology Data Exchange (ETDEWEB)

    Pendergrass II, R.A.; Mansker, L.D.; Hesketh, R.P.

    1995-08-01

    The goal of this project is to investigate the conditions in which volatiles will bum within both the dense and freeboard regions of fluidized beds. Experiments using a fluidized bed operated at incipient fluidization are being conducted to characterize the effect of particle surface area, initial fuel concentration, and particle type on the inhibition of volatiles within a fluidized bed. The work conducted during the period 4 December, 1994 through, 3 March 1995 is presented in this technical progress report. The research consists of the application of a detailed chemical kinetics model for propane combustion and planned improvements in the experimental system.

  8. [Special beds. Pulmonary therapy system].

    Science.gov (United States)

    Calixto Rodríguez, Joaquín; Rodríguez Martínez, Xavier; Marín i Vivó, Gemma; Paunellas Albert, Josep

    2008-10-01

    To be bedridden reduces one's capacity to move and produces muscular debility that affects the respiratory system leading to a decreased effectiveness in expectoration, the ability to spit up sputum. The pulmonary therapy system integrated in a bed is the result of applying motorized elements to the articulation points of the bad in order to achieve safe positions at therapeutic angles, which improve the breathing-perfusion (blood flow) relationship. This system also makes it possible to apply vibration waves to the patient which favor the elimination of bronchial-pulmonary secretions, the rehabilitation of the bedridden patient and decrease the work load for nursing personnel.

  9. Designing a CR Test bed

    DEFF Research Database (Denmark)

    2014-01-01

    with their own set up, since the potential costs and efforts could not pay back in term of expected research results. Software Defined Radio solutions offer an easy way to communication researchers for the development of customized research test beds. While several hardware products are commercially available......, an overview on common research-oriented software products for SDR development, namely GNU Radio, Iris, and ASGARD, will be provided, including how to practically start the software development of simple applications. Finally, best practices and examples of all the software platforms will be provided, giving...

  10. Improving Operability of Lab-Scale Spouted Bed Using Global Stochastic Optimization

    Directory of Open Access Journals (Sweden)

    Dr.Ghanim.M. Alwan

    2015-01-01

    Full Text Available A spouted bed is a special case of fluidization. It is an effective means of contacting gas with coarse solid particles .Gas-solid spouted beds are either cylindrical bed with cone base or the whole bed is in a cone shape where the gas enters as a jet. The gas forms a spout region that carries the solids upward in a diluted phase that forms a fountain at the top of the bed where the solids fall down and move downward in the annular region. Performance of gas-solid spouted bed benefit from solids uniformity structure with lower pressure drop (PD.Dropping of PD across a spouted bed could reduce the dissipated pumping energy and improve stability and uniformity of solid particles. The objective of this work is to study and selecting best operating conditions that could minimize PD across the bed. Optimization technique is a powerful tool would guide the experimental work and reduce the risk and cost for design and operation Hence, PD is to be considered as objective function of the optimization process .Three selected decision variables are affecting objective function. These decision variables are gas velocity, particle density and particle diameter. Steady-state measurements were carried out in a narrow 3-inch (0.076 m ID cylindrical spouted bed made of Plexiglas that used 60° conical shape base. Radial concentration of particles (glass and steel beads at various bed heights under different flow patterns were measured using sophisticated optical probes. A superficial velocity of air ranging from 0.74 to 1.0 m/s .PD was measured across the bed by high accuracy pressure transducers. Stochastic Genetic Algorithm (GA has found suitable global search for the non-linear hybrid spouted bed. Optimum results could select the best operating conditions for high-performance and stable conditions. Uniformity and stability of solid particles in the bed would enhance hydrodynamic parameters, heat and mass transfer. Best Operability of the bed was observed with

  11. Influence of Chemical and Thermodynamic Parameters on the Flue Gas Desulphurization Efficiency in a Circulating Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    Baoguo FAN; Changfu YOU; Haiying QI; Guangming XIANG; Xuchang XU

    2001-01-01

    An experimental study has been performed systematically on flue gas desulphurization by using circulating fluidized bed. The relationship, between desulphurization efficiency and the parameters of thermodynamics and chemistry, was investigated basically. It is shown that the bed temperature and the vapor partial pressure in the bed are the important parameters that influence the desulphurization efficiency. The closer the bed temperature to the dew point and the higher the vapor partial pressure, the higher is the desulphurization efficiency. With increasing of Ca/S, the desulphurization efficiency ascends. Comparing with different operating methods, the optimum method has been found.

  12. Comparison of the Efficiency of Moving- and Fixed-bed Bioreactors for Treatment of High-strength Synthetic Wastewater

    OpenAIRE

    Rezaee, A.; S Jorfi; Cheshmeh Soltani, R. D

    2012-01-01

    A lab-scale Plexiglas cubic container as a pre-aeration reactor with total volume of 10 L, and two integrated bioreactors including a moving-bed bioreactor (MBBR) and a fixed-bed bioreactor with total volume of 30 L separately were used for experimental study. The main purpose was to compare the performance of moving-bed and fixed-bed reactors for degradation of high organic loading in synthetic wastewater. Varying organic loadings of 0.5 to 9 kg COD m3 d–1 were applied. Generally, the tot...

  13. Experiment research on grain drying process in the heat pump assisted fluidized beds

    Institute of Scientific and Technical Information of China (English)

    Jing Yang; Li Wang; Fi Xiang; Lige Tong; Hua Su

    2004-01-01

    A heat pump assisted fluidized bed grain drying experimental system was developed. Based on this system, a serial of experiments was performed under four kinds of air cycle conditions. According to the experimental analysis, an appropriate drying medium-air cycle for the heat pump assisted fluidized bed drying equipment was decided, which is different from the commonly used heat pump assisted drying system. The experimental results concerning the drying operation performance of the new system show that the averaged coefficient of performance (COP) can reach more than 2.5. The economical evaluation was performed and the powefficiency and great application potentiality in future market.

  14. EXTERNAL-LOOP AIRLIFT MAGNETICALLY STABILIZED BED--MINIMUM STABILIZATION AND FLUIDIZATION CONDITIONS

    Institute of Scientific and Technical Information of China (English)

    Jordan Hristov

    2005-01-01

    Experimental study of an airlift with a magnetically stabilized bed in the riser bottom has been performed.External magnetic field allows easy control of magnetized bed structure and liquid circulation rate. Minimum stabilization and fluidization conditions have been determined experimentally and by a three-line graphical method. Semi-empirical data correlations of sections of the experimental curves have been performed. Scaling relationships known from non-magnetic airlift are applicable too, but with the assumption that the magnetic field affects the loop friction coefficient only.

  15. Preliminary study of a radiantly heated fluidized bed for the production of high purity silicon

    Science.gov (United States)

    Levenspiel, O.; Larson, M.; Zhang, G. T.; Ouyang, F.

    1983-01-01

    The preparation of very pure silicon from silane (SIH4) using radiant heating of the hot silicon particles of a fluidized bed is discussed. The fraction of electrical energy supplied to the heater which is actually absorbed by the particles and the heat transfer coefficient between the hot bed and the cool distributor plate were investigated. The experimental design is presented and the results of the study are summarized.

  16. Spectral analysis of CFB data: Predictive models of Circulating Fluidized Bed combustors

    Energy Technology Data Exchange (ETDEWEB)

    Gamwo, I.K.; Miller, A.; Gidaspow, D.

    1992-04-01

    The overall objective of this investigation is to develop experimentally verified models for circulating fluidized bed (CFB) combustors. Spectral analysis of CFB data obtained at Illinois Institute of Technology shows that the frequencies of pressure oscillations are less than 0.1 Hertz and that they increase with solids volume fraction to the usual value of one Hertz obtained in bubbling beds. These data are consistent with the kinetic theory interpretation of density wave propagation.

  17. (México. Un estudio exploratorio

    Directory of Open Access Journals (Sweden)

    Patricia Mercado Salgado

    2007-01-01

    Full Text Available En un mundo globalizado, el sector empresarial no puede seguir negando la necesidad de adoptar la responsabilidad social como estrategia para alcanzar beneficios externos e internos, pues sigue latente cierto comportamiento dominante de rechazo hacia ella. Por ello, el objetivo de esta investigación exploratoria, no experimental, es describir la responsabilidad social en empresas del Valle de Toluca (México mediante cuatro componentes: ética empresarial, preservación del medio ambiente, calidad de vida en el trabajo y vinculación empresa-sociedad, en una muestra no probabilística de 31 empresas. Los resultados reflejan que las empresas se encuentran en el nivel inicial de filantropía, detectándose la voluntad de la alta dirección y de los accionistas como factores que podrían favorecer la adopción de la responsabilidad social. Queda para futuras investigaciones incrementar la muestra e incluir el desempeño económico en este tipo de estudios.

  18. Novel Simulated moving bed technologies

    Energy Technology Data Exchange (ETDEWEB)

    Purdue University

    2003-12-30

    Cellulose and hemicellulose from plants and other biomass can be hydrolyzed to produce sugars (i.e. glucose and xylose). Once these sugars are separated from other impurities, they can serve as feedstock in fermentation to produce ethanol (as fuels), lactic acid, or other valuable chemicals. The need for producing fuels and chemicals from renewable biomass has become abundantly clear over the last decade. However, the cost of producing fermentable sugars from biomass hydrolyzate using existing technology is relatively high and has been a major obstacle. The objective of this project is to develop an efficient and economical simulated moving bed (SMB) process to recover fermentable sugars from biomass hydrolyzate. Sulfuric acid can hydrolyze the cellulose and hemicellulose in biomass to sugars, but this process can generate byproducts such as acetic acid, and can lead to further degradation of the xylose to furfural and glucose to hydroxymethyl furfural (HMF). Also, lignin and other compounds in the biomass will degrade to various phenolic compounds. If the concentrations of these compounds exceed certain threshold levels, they will be toxic to the downstream fermentation, and will severely limit the usefulness of the derived sugars. Standard post-hydrolysis processing involves neutralization of sulfuric acid, usually with lime (calcium hydroxide). A study by Wooley et al.showed that the limed hydrolyzate gave a low ethanol yield in fermentation test (20% of theoretical yield compared to 77% of theoretical yield from fermentation of pure sugars). They showed that instead of adding lime, an ion exclusion chromatography process could be used to remove acids, as well as to isolate the sugars from the biomass hydrolyzate. In this project, we investigated the feasibility of developing an economical SMB process based on (1) a polymeric adsorbent, Dowex99, which was used by Wooley et al., (2) a second polymeric adsorbent, poly-4-vinyl pyridine (or PVP in short, Reilly

  19. The WCSAR telerobotics test bed

    Science.gov (United States)

    Duffie, N.; Zik, J.; Teeter, R.; Crabb, T.

    1988-01-01

    Component technologies for use in telerobotic systems for space are being developed. As part of this effort, a test bed was established in which these technologies can be verified and integrated into telerobotic systems. The facility consists of two slave industrial robots, an articulated master arm controller, a cartesian coordinate master arm controller, and a variety of sensors, displays and stimulators for feedback to human operators. The controller of one of the slave robots remains in its commercial state, while the controller of the other robot has been replaced with a new controller that achieves high-performance in telerobotic operating modes. A dexterous slave hand which consists of two fingers and a thumb is being developed, along with a number of force-reflecting and non-force reflecting master hands, wrists and arms. A tactile sensing finger tip based on piezo-film technology has been developed, along with tactile stimulators and CAD-based displays for sensory feedback and sensory substitution. The telerobotics test bed and its component technologies are described, as well as the integration of these component technologies into telerobotic systems, and their performance in conjunction with human operators.

  20. Model investigations 3D of gas-powder two phase flow in descending bed with consideration radial distribution of flow

    Directory of Open Access Journals (Sweden)

    B. Panic

    2013-04-01

    Full Text Available The results of experimental investigations concerning radial distribution of powder accumulation in bed and static pressure were presented in this paper. To realize this research physical model of gas-powder two phase flow with descending bed was projected and constructed. Amounts of “dynamic” and “static” powder accumulated in bed, in dependence on gas velocity and of bed particles were investigated. In 3D model “static” powder (with its radial distribution at the tuyere level and in the higher part of bed was measured. The influence of bed particles, powder and gas radial distribution on values of interaction forces between flow phases in investigated system was defined.

  1. The effects of emotional awareness training on teachers’ ability to manage the emotions of preschool children: An experimental study (Efectos del desarrollo de la conciencia emocional en la capacidad de los profesores para gestionar las emociones de niños en edad preescolar: un estudio experimental

    Directory of Open Access Journals (Sweden)

    Maria Ulloa

    2016-04-01

    Full Text Available This article describes the process and results of a Randomized Controlled Trial (RCT on teachers’ ability to manage the emotions of preschool children during a constrained play activity. Thirty early childhood education teachers participated in the study. Half of the participants were taught strategies to enhance their own emotional competence. The control group was provided with standard information on child development. The experimental group was trained in active strategies on emotion coaching, emotional schemas, reflective practice focused on emotions, and mindfulness training. The teachers’ outcomes were assessed in situ during a pretend play session with small groups of preschoolers. The dependent variables were observed occurrences of different components of emotional competence in teachers. Significant statistical differences were found between the two groups across the three different emotional competence skills (regulation, expression, and knowledge demonstrated by the early childhood teachers during a game situation. This experimental study highlights the processes through which teachers support the emotional competence of young children, and the importance of the role of early childhood teachers' own emotional competence on the socialisation of children’s emotions. Most importantly, it provides evidence, based on the influence of emotion-focused teacher-training and reflective practices, that teachers’ emotional skills should be supported such that they can optimally meet the emotional needs of young children.

  2. Flow and fracture in water-saturated, unconstrained granular beds

    Directory of Open Access Journals (Sweden)

    Germán eVaras

    2015-06-01

    Full Text Available The injection of gas in a liquid-saturated granular bed gives rise to a wide variety of invasion patterns. Many studies have focused on constrained porous media, in which the grains are fixed in the bed and only the interstitial fluid flows when the gas invades the system. With a free upper boundary, however, the grains can be entrained by the ascending gas or fluid motion, and the competition between the upward motion of grains and sedimentation leads to new patterns. We propose a brief review of the experimental investigation of the dynamics of air rising through a water-saturated, unconstrained granular bed, in both two and three dimensions. After describing the invasion pattern at short and long time, a tentative regime-diagram is proposed. We report original results showing a dependence of the fluidized zone shape, at long times, on the injection flow rate and grain size. A method based on image analysis makes it possible to detect not only the fluidized zone profile in the stationary regime, but also to follow the transient dynamics of its formation. Finally, we describe the degassing dynamics inside the fluidized zone, in the stationary regime. Depending on the experimental conditions, regular bubbling, continuous degassing, intermittent regime or even spontaneous flow-to-fracture transition are observed.

  3. Evaporative heat transfer in beds of sensible heat pellets

    Energy Technology Data Exchange (ETDEWEB)

    Arimilli, R.V.; Moy, C.A. [Univ. of Tennessee, Knoxville, TN (United States)

    1989-03-01

    An experimental study of boiling/evaporative heat transfer from heated spheres in vertical packed beds with downward liquid-vapor flow of Refrigerant-113 was conducted. Surface superheats of 1 to 50{degrees}C, mass flow rates of 1.7 to 5.6 Kg/min, sphere diameters of 1.59 and 2.54 cm, quality (i.e., mass fraction of vapor) of the inlet flow of 0.02 to 1.0, and two surface conditions were considered. Instrumented smooth and rough aluminum spheres were used to measure the heat transfer coefficients under steady state conditions. Heat transfer coefficients were independently determined for each sphere at three values three values of surface superheat. The quantitative results of this extensive experimental study are successfully correlated. The correlation equation for the boiling heat transfer coefficients is presented in terms of a homogeneous model. The correlation may be used in the development of numerical models to simulate the transient thermal performance of packed bed thermal energy storage unit while operating as an evaporator. The boiling of the liquid-vapor flow around the spheres in the packed bed was visually observed with a fiber-optic baroscope and recorded on a videotape. The visualization results showed qualitatively the presence of four distinct flow regimes. One of these occurs under saturated inlet conditions and are referred to as the Low-quality, Medium-quality, and High-quality Regimes. The regimes are discussed in detail in this paper.

  4. Packed fluidized bed blanket for fusion reactor

    Science.gov (United States)

    Chi, John W. H.

    1984-01-01

    A packed fluidized bed blanket for a fusion reactor providing for efficient radiation absorption for energy recovery, efficient neutron absorption for nuclear transformations, ease of blanket removal, processing and replacement, and on-line fueling/refueling. The blanket of the reactor contains a bed of stationary particles during reactor operation, cooled by a radial flow of coolant. During fueling/refueling, an axial flow is introduced into the bed in stages at various axial locations to fluidize the bed. When desired, the fluidization flow can be used to remove particles from the blanket.

  5. Investigation of debris bed formation, spreading and coolability

    Energy Technology Data Exchange (ETDEWEB)

    Kudinov, P.; Konovalenko, A.; Grishchenko, D.; Yakush, S.; Basso, S.; Lubchenko, N.; Karbojian, A. [Royal Institute of Technology, KTH. Div. of Nuclear Power Safety, Stockholm (Sweden)

    2013-08-15

    The work is motivated by the severe accident management strategy adopted in Nordic type BWRs. It is assumed that core melt ejected from the vessel will fragment, quench and form a coolable debris bed in a deep water pool below the vessel. In this work we consider phenomena relevant to the debris bed formation and coolability. Several DEFOR-A (Debris Bed Formation - Agglomeration) tests have been carried out with new corium melt material and a melt releasing nozzle mockup. The influence of the melt material, melt superheat, jet free fall height on the (i) faction of agglomerated debris, (ii) particle size distribution, (iii) ablation/plugging of the nozzle mockup has been addressed. Results of the DECOSIM (Debris Coolability Simulator) code validation against available COOLOCE data are presented in the report. The dependence of DHF on system pressure from COOLOCE experiments can be reproduced quite accurately if either the effective particle diameter or debris bed porosity is increased. For a cylindrical debris bed, good agreement is achieved in DECOSIM simulations for the particle diameter 0.89 mm and porosity 0.4. The results obtained are consistent with MEWA simulation where larger particle diameters and porosities were found to be necessary to reproduce the experimental data on DHF. It is instructive to note that results of DHF prediction are in better agreement with POMECO-HT data obtained for the same particles. It is concluded that further clarification of the discrepancies between different experiments and model predictions. In total 13 exploratory tests were carried out in PDS (particulate debris spreading) facility to clarify potential influence of the COOLOCE (VTT) facility heaters and TCs on particle self-leveling process. Results of the preliminary analysis suggest that there is no significant influence of the pins on self-leveling, at least for the air superficial velocities ranging from 0.17 up to 0.52 m/s. Further confirmatory tests might be needed

  6. Theorical and experimental study of the induced forces by the mixed, divergent, convergent and straight labyrinth of seal systems on the steam turbines, gas turbines and compressor rotors; Estudio teorico-experimental de las fuerzas inducidas por los sistemas de sellos de laberinto rectos, convergentes, divergentes y mixtos sobre los rotores de turbinas de vapor, turbinas de gas y compresores

    Energy Technology Data Exchange (ETDEWEB)

    Salazar San Andres, Octavio Ramon

    1991-12-31

    A theoretical and experimental research is conducted in order to determine the labyrinth seal forces, as well as the stiffness and damping coefficients for straight, convergent, divergent, and combined shapes on turbine and compressor rotors. The mathematical model is deduced on the basis of the single volume method and its solution is obtained by the perturbation procedure. The validation is achieved with published results. Experimental work carried out on a test bench is described in the text. This involved labyrinth seals with straight, convergent, and divergent profiles, as the published information relating to mixed type is sufficient to perform the evaluation. The conclusions demonstrate that the model is able to predict and determine the performance of labyrinth seals based on forces and rotordynamic coefficients for static and dynamic motions. Finally, tests on real steam turbines of 300 MW are recommended. In this case the high pressures and use of wheels with strips on the periphery and supported by the upper part of blades, increase the susceptibility of self excited subsynchronous vibrations. [Espanol] Se presenta una investigacion teorica-experimental relacionada con la obtencion y validacion de un modelo matematico capaz de predecir las fuerzas y los coeficientes de rigidez y amortiguamiento de los sellos de laberinto de tipo recto, convergente, divergente y mixto que se emplean en turbinas y compresores tanto terrestres como aereos. El modelo matematico propuesto se deduce a partir del metodo de un solo volumen y su solucion se obtiene a traves de metodos perturbatorios. La validacion del mismo se consigue al comparar con resultados experimentales publicados en revistas especializadas y con los datos medidos en un banco de pruebas cuya descripcion se incluye en el trabajo, cualculado para sellos rectos, convergentes y divergentes, ya que la informacion publicada respecto al tipo mixto o combinado es suficiente. Las conclusiones de la investigacion

  7. Coupling scales for modelling heavy metal vaporization from municipal solid waste incineration in a fluid bed by CFD

    Energy Technology Data Exchange (ETDEWEB)

    Soria, José, E-mail: jose.soria@probien.gob.ar [Institute for Research and Development in Process Engineering, Biotechnology and Alternative Energies (PROBIEN, CONICET – UNCo), 1400 Buenos Aires St., 8300 Neuquén (Argentina); Gauthier, Daniel; Flamant, Gilles [Processes, Materials and Solar Energy Laboratory (PROMES-CNRS, UPR 8521), 7 Four Solaire Street, Odeillo, 66120 Font-Romeu (France); Rodriguez, Rosa [Chemical Engineering Institute, National University of San Juan, 1109 Libertador (O) Avenue, 5400 San Juan (Argentina); Mazza, Germán [Institute for Research and Development in Process Engineering, Biotechnology and Alternative Energies (PROBIEN, CONICET – UNCo), 1400 Buenos Aires St., 8300 Neuquén (Argentina)

    2015-09-15

    Highlights: • A CFD two-scale model is formulated to simulate heavy metal vaporization from waste incineration in fluidized beds. • MSW particle is modelled with the macroscopic particle model. • Influence of bed dynamics on HM vaporization is included. • CFD predicted results agree well with experimental data reported in literature. • This approach may be helpful for fluidized bed reactor modelling purposes. - Abstract: Municipal Solid Waste Incineration (MSWI) in fluidized bed is a very interesting technology mainly due to high combustion efficiency, great flexibility for treating several types of waste fuels and reduction in pollutants emitted with the flue gas. However, there is a great concern with respect to the fate of heavy metals (HM) contained in MSW and their environmental impact. In this study, a coupled two-scale CFD model was developed for MSWI in a bubbling fluidized bed. It presents an original scheme that combines a single particle model and a global fluidized bed model in order to represent the HM vaporization during MSW combustion. Two of the most representative HM (Cd and Pb) with bed temperatures ranging between 923 and 1073 K have been considered. This new approach uses ANSYS FLUENT 14.0 as the modelling platform for the simulations along with a complete set of self-developed user-defined functions (UDFs). The simulation results are compared to the experimental data obtained previously by the research group in a lab-scale fluid bed incinerator. The comparison indicates that the proposed CFD model predicts well the evolution of the HM release for the bed temperatures analyzed. It shows that both bed temperature and bed dynamics have influence on the HM vaporization rate. It can be concluded that CFD is a rigorous tool that provides valuable information about HM vaporization and that the original two-scale simulation scheme adopted allows to better represent the actual particle behavior in a fluid bed incinerator.

  8. Enhanced stability of steep channel beds to mass failure and debris flow initiation

    Science.gov (United States)

    Prancevic, J.; Lamb, M. P.; Ayoub, F.; Venditti, J. G.

    2015-12-01

    Debris flows dominate bedrock erosion and sediment transport in very steep mountain channels, and are often initiated from failure of channel-bed alluvium during storms. While several theoretical models exist to predict mass failures, few have been tested because observations of in-channel bed failures are extremely limited. To fill this gap in our understanding, we performed laboratory flume experiments to identify the conditions necessary to initiate bed failures in non-cohesive sediment of different sizes (D = 0.7 mm to 15 mm) on steep channel-bed slopes (S = 0.45 to 0.93) and in the presence of water flow. In beds composed of sand, failures occurred under sub-saturated conditions on steep bed slopes (S > 0.5) and under super-saturated conditions at lower slopes. In beds of gravel, however, failures occurred only under super-saturated conditions at all tested slopes, even those approaching the dry angle of repose. Consistent with theoretical models, mass failures under super-saturated conditions initiated along a failure plane approximately one grain-diameter below the bed surface, whereas the failure plane was located near the base of the bed under sub-saturated conditions. However, all experimental beds were more stable than predicted by 1-D infinite-slope stability models. In partially saturated sand, enhanced stability appears to result from suction stress. Enhanced stability in gravel may result from turbulent energy losses in pores or increased granular friction for failures that are shallow with respect to grain size. These grain-size dependent effects are not currently included in stability models for non-cohesive sediment, and they may help to explain better the timing and location of debris flow occurrence.

  9. CERTS Microgrid Laboratory Test Bed

    Energy Technology Data Exchange (ETDEWEB)

    Eto, Joe; Lasseter, Robert; Schenkman, Ben; Stevens, John; Klapp, Dave; Volkommer, Harry; Linton, Ed; Hurtado, Hector; Roy, Jean

    2009-06-18

    The objective of the CERTS Microgrid Test Bed project was to enhance the ease of integrating energy sources into a microgrid. The project accomplished this objective by developing and demonstrating three advanced techniques, collectively referred to as the CERTS Microgrid concept, that significantly reduce the level of custom field engineering needed to operate microgrids consisting of generating sources less than 100kW. The techniques comprising the CERTS Microgrid concept are: 1) a method for effecting automatic and seamless transitions between grid-connected and islanded modes of operation, islanding the microgrid's load from a disturbance, thereby maintaining a higher level of service, without impacting the integrity of the utility's electrical power grid; 2) an approach to electrical protection within a limited source microgrid that does not depend on high fault currents; and 3) a method for microgrid control that achieves voltage and frequency stability under islanded conditions without requiring high-speed communications between sources. These techniques were demonstrated at a full-scale test bed built near Columbus, Ohio and operated by American Electric Power. The testing fully confirmed earlier research that had been conducted initially through analytical simulations, then through laboratory emulations,and finally through factory acceptance testing of individual microgrid components. The islanding and resychronization method met all Institute of Electrical and Electronics Engineers Standard 1547 and power quality requirements. The electrical protection system was able to distinguish between normal and faulted operation. The controls were found to be robust under all conditions, including difficult motor starts and high impedance faults. The results from these tests are expected to lead to additional testing of enhancements to the basic techniques at the test bed to improve the business case for microgrid technologies, as well to field

  10. Spatial correlations in bed load transport: evidence, importance, and modelling

    CERN Document Server

    Heyman, J; Mettra, F; Ancey, C

    2016-01-01

    This article examines the spatial {dynamics of bed load particles} in water. We focus particularly on the fluctuations of particle activity, which is defined as the number of moving particles per unit bed {length}. Based on a stochastic model recently proposed by \\citet{Ancey2013}, we derive the second moment of particle activity analytically; that is the spatial correlation functions of particle activity. From these expressions, we show that large moving particle clusters can develop spatially. Also, we provide evidence that fluctuations of particle activity are scale-dependent. Two characteristic lengths emerge from the model: a saturation length $\\ell_{sat}$ describing the length needed for a perturbation in particle activity to relax to the homogeneous solution, and a correlation length $\\ell_c$ describing the typical size of moving particle clusters. A dimensionless P\\'eclet number can also be defined according to the transport model. Three different experimental data sets are used to test the theoretica...

  11. Internal circulating fluidized bed incineration system and design algorithm.

    Science.gov (United States)

    Tian, W D; Wei, X L; Li, J; Sheng, H Z

    2001-04-01

    The internal circulating fluidized bed (ICFB) system is characterized with fast combustion, low emission, uniformity of bed temperature and controllability of combustion process. It is a kind of novel clean combustion system, especially for the low-grade fuels, such as municipal solid waste (MSW). The experimental systems of ICFB with and without combustion were designed and set up in this paper. A series of experiments were carried out for further understanding combustion process and characteristics of several design parameters for MSW. Based on the results, a design routine for the ICFB system was suggested for the calculation of energy balance, airflow rate, heat transfer rate, and geometry arrangement. A test system with ICFB combustor has been set up and the test results show that the design of the ICFB system is successful.

  12. Internal circulating fluidized bed system and design algorithm

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The internal circulating fluidized bed (ICFB) system ischaracterized with fast combustion, low emission, uniformity of bed temperature and controllability of combustion process. It is a kind of novel clean combustion system, especially for the low-grade fuels, such as municipal solid waste(MSW). The experimental systems of ICFB with and without combustion were designed and set up in this paper. A series of experiments were carried out for further understanding combustion process and characteristics of several design parameters for MSW. Based on the results, a design routine for the ICFB system was suggested for the calculation of energy balance, airflow rate, heat transfer rate, and geometry arrangement. A test system with ICFB combustor has been set up and the test results show that the design of the ICFB system issuccessful.

  13. Numerical Simulation of Asynchronous Simulated Moving Bed Chromatography

    Institute of Scientific and Technical Information of China (English)

    卢建刚

    2004-01-01

    Asynchronous simulated moving bed chromatography (ASMBC), known also as the "VARICOL" process, is more efficient and flexible than the well-known and traditional simulated moving bed chromatography (SMBC). A detailed model of ASMBC, taking account of non-linear competitive isotherms, mass transfer parameters, and complex port switching schedule parameters, was developed to simulate the complex dynamics of ASMBC.The simulated performance is in close agreement with the experimental data of chiral separation reported in the literature. The simulation results show that ASMBC can achieve the performance similar to SMBC with fewer columns and can achieve better performance than SMBC with the same total column number. All design and operation parameters can be chosen correctly by numerical simulation. This detailed ASMBC model and the numerical technique are useful for design, operation, optimization and scale-up of ASMBC.

  14. C. elegans BED domain transcription factor BED-3 controls lineage-specific cell proliferation during organogenesis

    OpenAIRE

    Inoue, Takao; Sternberg, Paul W.

    2010-01-01

    The control of cell division is critical to organogenesis, but how this control is achieved is not fully understood. We found that mutations in bed-3, encoding a BED Zn-finger domain transcription factor, confer a phenotype where a specific set of cell divisions during vulval organogenesis is lost. Unlike general cell cycle regulators in Caenorhabditis elegans, the function of bed-3 is restricted to specific lineages. Transcriptional reporters suggest that bed-3 is expressed in a limited numb...

  15. The Effects of Long Duration Bed Rest on Functional Mobility and Balance: Relationship to Resting State Motor Cortex Connectivity

    Science.gov (United States)

    Erdeniz, B.; Koppelmans, V.; Bloomberg, J. J.; Kofman, I. S.; DeDios, Y. E.; Riascos-Castaneda, R. F.; Wood, S. J.; Mulavara, A. P.; Seidler, R. D.

    2014-01-01

    NASA offers researchers from a variety of backgrounds the opportunity to study bed rest as an experimental analog for space flight. Extended exposure to a head-down tilt position during long duration bed rest can resemble many of the effects of a low-gravity environment such as reduced sensory inputs, body unloading and increased cephalic fluid distribution. The aim of our study is to a) identify changes in brain function that occur with prolonged bed rest and characterize their recovery time course; b) assess whether and how these changes impact behavioral and neurocognitive performance. Thus far, we completed data collection from six participants that include task based and resting state fMRI. The data have been acquired through the bed rest facility located at the University of Texas Medical Branch (Galveston, TX). Subjects remained in bed with their heads tilted down 6 degrees below their feet for 70 consecutive days. Behavioral measures and neuroimaging assessments were obtained at seven time points: a) 7 and 12 days before bed rest; b) 7, 30, and 65 days during bed rest; and c) 7 and 12 days after bed rest. Functional connectivity magnetic resonance imaging (FcMRI) analysis was performed to assess the connectivity of motor cortex in and out of bed rest. We found a decrease in motor cortex connectivity with vestibular cortex and the cerebellum from pre bed rest to in bed rest. We also used a battery of behavioral measures including the functional mobility test and computerized dynamic posturography collected before and after bed rest. We will report the preliminary results of analyses relating brain and behavior changes. Furthermore, we will also report the preliminary results of a spatial working memory task and vestibular stimulation during in and out of bed rest.

  16. Sand Bed Morphodynamics under Standing Waves and Vegetated Conditions

    Science.gov (United States)

    Landry, B. J.; Garcia, M. H.

    2010-12-01

    Littoral processes such as sediment transport, wave attenuation, and boundary layer development are governed by the presence of bathymetric features, which include large-scale sand bars upon which smaller-scale sand ripples are superimposed, as well as the presence of submarine vegetation. Numerous studies on sand ripples and bars have aided to elucidate the dynamics in oscillatory flows; however, the effect of vegetation on the system is less understood. Recent laboratory studies have focused on quantifying wave attenuation by emergent vegetation as a natural method to mitigate storm surges. The emergent vegetation, while promising for coastal protection, alters sediment transport rates directly by the physical presence of the plants near the bed and indirectly from reduction in near-bed shear stresses due to attenuated wave energy. The experimental work herein focuses on the area near the deeply submerged vegetated canopy limit (current work has a ratio of mean still water depth to plant height, H/h, = 7.9) to minimize the effect on the surface waves and discern the direct impact vegetation has on sand bed morphodynamics. Experiments were conducted in the large wave tank (49-m long by 1.83-m wide by 1.22-m deep) in the Ven Te Chow Hydrosystems Laboratory at the University of Illinois in which a high reflection wave forcing was used over a uniform sand bed with a 0.25-mm median sediment diameter in which staggered and uniform arrangements of idealized vegetation (i.e., 6.35-mm diameter rigid wooden cylinders) were positioned along the bed (e.g., at predetermined sand bar troughs and over an entire sand bar). The resulting bathymetric evolution from the vegetated case experiments were compared to the base case of no vegetation using two optical methods: a high-resolution laser displacement sensor for three-dimensional surveys and digitized profiles via high-definition panoramic images of the entire test section. The experimental findings illustrate the profound

  17. Flue gas desulfurization by rotating beds

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, N.; Keyvani, M.; Coskundeniz, A.

    1992-01-01

    The operating and mass transfer characteristics of rotating foam metal beds were studied to determine the potential for flue gas desulfurization. This is a final technical report on the work supported by DOE [number sign]FG22-87-PC79924. The report is divided into two sections, Part 1 deals primarily with the operating characteristics of rotating beds, and Part 2 covers the mass transfer characteristics of S0[sub 2] absorption in water-lime slurries. Rotating foam metal beds are in essence packed towers operated in high gravitational fields. The foam metal bed is in the form of a cylindrical donut, or torus, and is rotated to produced the high centrifugal forces. The liquid phase enters the bed at the inner surface of the torus and is pulled by the field through the bed. Gas flows countercurrent to the liquid. The bed packing can have a very large specific surface areas and not flood. Possible benefits include much smaller height of a transfer unit resulting in smaller equipment and supporting structures, reduced solvent inventory, faster response with improved process control, reduced pressure drop, and shorter startup and shut-down times. This work is concerned broadly with the operating characteristics of rotating beds, the objectives being to (1) determine the pressure drop through the rotating bed; (2) determine the power required to operate the beds, (3) investigate the residence time distribution of the liquid phase in the beds; and (4) determine the mass transfer coefficients of S0[sub 2] absorption. Three packings of differing specific surface areas were studied, with areas ranging from 656 to 2952 m[sub 2]/m[sub 3]. Liquid flow rates to 36 kg/s*m[sub 2], gas flow rate to 2.2 kg/s*m[sub 2], and gravitational fields to 300 g were covered in this study.

  18. Fluidized bed coal combustion reactor

    Science.gov (United States)

    Moynihan, P. I.; Young, D. L. (Inventor)

    1981-01-01

    A fluidized bed coal reactor includes a combination nozzle-injector ash-removal unit formed by a grid of closely spaced open channels, each containing a worm screw conveyor, which function as continuous ash removal troughs. A pressurized air-coal mixture is introduced below the unit and is injected through the elongated nozzles formed by the spaces between the channels. The ash build-up in the troughs protects the worm screw conveyors as does the cooling action of the injected mixture. The ash layer and the pressure from the injectors support a fluidized flame combustion zone above the grid which heats water in boiler tubes disposed within and/or above the combustion zone and/or within the walls of the reactor.

  19. CERTS Microgrid Laboratory Test Bed

    Energy Technology Data Exchange (ETDEWEB)

    ETO, J.; LASSETER, R.; SCHENKMAN, B.; STEVENS, J.; KLAPP, D.; VOLKOMMER, H.; LINTON, E.; HURTADO, H.; ROY, J.

    2010-06-08

    The objective of the CERTS Microgrid Test Bed project was to enhance the ease of integrating energy sources into a microgrid. The project accomplished this objective by developing and demonstrating three advanced techniques, collectively referred to as the CERTS Microgrid concept, that significantly reduce the level of custom field engineering needed to operate microgrids consisting of generating sources less than 100kW. The techniques comprising the CERTS Microgrid concept are: 1 a method for effecting automatic and seamless transitions between grid-connected and islanded modes of operation, islanding the microgrid's load from a disturbance, thereby maintaining a higher level of service, without impacting the integrity of the utility's electrical power grid; 2 an approach to electrical protection within a limited source microgrid that does not depend on high fault currents; and 3 a method for microgrid control that achieves voltage and frequency stability under islanded conditions without requiring high-speed communications between sources.

  20. Metabolic Resistance in Bed Bugs

    Directory of Open Access Journals (Sweden)

    Omprakash Mittapalli

    2011-03-01

    Full Text Available Blood-feeding insects have evolved resistance to various insecticides (organochlorines, pyrethroids, carbamates, etc. through gene mutations and increased metabolism. Bed bugs (Cimex lectularius are hematophagous ectoparasites that are poised to become one of the major pests in households throughout the United States. Currently, C. lectularius has attained a high global impact status due to its sudden and rampant resurgence. Resistance to pesticides is one factor implicated in this phenomenon. Although much emphasis has been placed on target sensitivity, little to no knowledge is available on the role of key metabolic players (e.g., cytochrome P450s and glutathione S-transferases towards pesticide resistance in C. lectularius. In this review, we discuss different modes of resistance (target sensitivity, penetration resistance, behavioral resistance, and metabolic resistance with more emphasis on metabolic resistance.