WorldWideScience

Sample records for baffles

  1. Baffle construction notes

    DEFF Research Database (Denmark)

    Jørgensen, John Leif

    1998-01-01

    The design process for multi-stage high performance straylight suppression baffles for star trackers are described. Furthermore details for manufacturing are given......The design process for multi-stage high performance straylight suppression baffles for star trackers are described. Furthermore details for manufacturing are given...

  2. Baffle construction notes

    DEFF Research Database (Denmark)

    Jørgensen, John Leif

    1997-01-01

    The procedures for manufacturing CFRP based stray light suppresion structures are described. Examples from production ofthe baffle designed for the "Astrid 2" and "TEAMSAT" missions are given......The procedures for manufacturing CFRP based stray light suppresion structures are described. Examples from production ofthe baffle designed for the "Astrid 2" and "TEAMSAT" missions are given...

  3. Nuclear core baffling apparatus

    International Nuclear Information System (INIS)

    Cooper, F.W. Jr.; Silverblatt, B.L.; Knight, C.B.; Berringer, R.T.

    1979-01-01

    An apparatus for baffling the flow of reactor coolant fluid into and about the core of a nuclear reactor is described. The apparatus includes a plurality of longitudinally aligned baffle plates with mating surfaces that allow longitudinal growth with temperature increases while alleviating both leakage through the aligned plates and stresses on the components supporting the plates

  4. Modelling of baffled stirred tanks

    Energy Technology Data Exchange (ETDEWEB)

    Ahlstedt, H.; Lahtinen, M. [Tampere Univ. of Technology (Finland). Energy and Process Engineering

    1996-12-31

    The three-dimensional flow field of a baffled stirred tank has been calculated using four different turbulence models. The tank is driven by a Rushton-type impeller. The boundary condition for the impeller region has been given as a source term or by calculating the impeller using the sliding mesh technique. Calculated values have been compared with measured data. (author)

  5. Advanced baffle materials technology development

    Science.gov (United States)

    Johnson, E. A.; Vonbenken, C. J.; Halverson, W. D.; Evans, R. D.; Wollam, J. S.

    1991-10-01

    Optical sensors for strategic defense will require optical baffles to achieve adequate off-axis stray light rejection and pointing accuracy. Baffle materials must maintain their optical performance after exposure to both operational and threat environments. In addition, baffle materials must not introduce contamination which would compromise the system signal-to-noise performance or impair system mission readiness. Critical examination of failure mechanisms in current baffle materials are quite fragile and contribute to system contamination problems. Spire has developed technology to texture the substrate directly, thereby, removing minute, fragile interfaces subject to mechanical failure. This program has demonstrated that ion beam texturing produces extremely dark surfaces which are immune to damage from ordinary handling. This technology allows control of surface texture feature size and hence the optical wavelength at which the surface absorbs. The USAMTL/Spire program has produced dramatic improvements in the reflectance of ion beam textured aluminum without compromising mechanical hardness. In simulated launch vibration tests, this material produced no detectable contamination on adjacent catcher plates.

  6. Nuclear reactor core flow baffling

    International Nuclear Information System (INIS)

    Berringer, R.T.

    1979-01-01

    A flow baffling arrangement is disclosed for the core of a nuclear reactor. A plurality of core formers are aligned with the grids of the core fuel assemblies such that the high pressure drop areas in the core are at the same elevations as the high pressure drop areas about the core periphery. The arrangement minimizes core bypass flow, maintains cooling of the structure surrounding the core, and allows the utilization of alternative beneficial components such as neutron reflectors positioned near the core

  7. Thermal baffle for fast-breeder reactor

    International Nuclear Information System (INIS)

    Rylatt, J.A.

    1977-01-01

    A liquid-metal-cooled fast-breeder reactor includes a bridge structure for separating hot outlet coolant from relatively cool inlet coolant consisting of an annular stainless steel baffle plate extending between the core barrel surrounding the core and the thermal liner associated with the reactor vessel and resting on ledges thereon, there being inner and outer circumferential webs on the lower surface of the baffle plate and radial webs extending between the circumferential webs, a stainless steel insulating plate completely covering the upper surface of the baffle plate and flex seals between the baffle plate and the ledges on which the baffle plate rests to prevent coolant from washing through the gaps therebetween. The baffle plate is keyed to the core barrel for movement therewith and floating with respect to the thermal liner and reactor vessel. 3 claims, 2 figures

  8. Advanced infrared optically black baffle materials

    International Nuclear Information System (INIS)

    Seals, R.D.; Egert, C.M.; Allred, D.D.

    1990-01-01

    Infrared optically black baffle surfaces are an essential component of many advanced optical systems. All internal surfaces in advanced infrared optical sensors that require stray light management to achieve resolution are of primary concern in baffle design. Current industrial materials need improvements to meet advanced optical sensor systems requirements for optical, survivability, and endurability. Baffles are required to survive and operate in potentially severe environments. Robust diffuse-absorptive black surfaces, which are thermally and mechanically stable to threats of x-ray, launch, and in-flight maneuver conditions, with specific densities to allow an acceptable weight load, handleable during assembly, cleanable, and adaptive to affordable manufacturing, are required as optical baffle materials. In this paper an overview of recently developed advanced infrared optical baffle materials, requirements, manufacturing strategies, and the Optics MODIL (Manufacturing Operations Development and Integration Laboratory) Advanced Baffle Program are discussed

  9. Core baffle for nuclear reactors

    International Nuclear Information System (INIS)

    Machado, O.J.; Berringer, R.T.

    1977-01-01

    The invention concerns the design of the core of a LWR with a large number of fuel assemblies formed by fuel rods and kept in position by spacer grids. According to the invention, at the level of the spacer grids match plates are mounted with openings so the flow of coolant directed upwards will not be obstructed and a parallel bypass will be obtained in the space between the core barrel and the baffle plates. In case of an accident, this configuration reduces or avoids damage from overpressure reactions. (HP) [de

  10. Mixed convection in a baffled grooved channel

    Indian Academy of Sciences (India)

    For the present study, external flow from both left and right of the grooved channel are considered. A remarkable enhancement of heat transfer is observed in presence of baffle. The study has also pointed out that for optimal performance, the position and height of the baffle need to be adjusted depending on the direction of ...

  11. Mixed convection in a baffled grooved channel

    Indian Academy of Sciences (India)

    A remarkable enhancement of heat transfer is observed in presence of baffle. The study has also pointed out that for optimal performance, the position and height of the baffle need to be adjusted depending on the direction of external flow. Keywords. Heat transfer; grooved channel; mixed convection; Richardson number;.

  12. 5/8'' baffle bolt replacement

    International Nuclear Information System (INIS)

    Pinaud, T.; Grypczynski, D.

    1999-01-01

    Both Framatome Nuclear Services in France and its U.S. arm, FT1, are now equipped with baffle bolt inspection and replacement packages. These packages allow them to tackle baffle bold degradation on both two- and three-loop nuclear power plants. Framatome and FT1 together are world leaders in addressing reactor vessel internal bolting concerns

  13. Mixed convection in a baffled grooved channel

    Indian Academy of Sciences (India)

    In the present numerical work, flow structure and heat transfer characteristics are investigated in a baffled grooved channel, differentially heated from the sides. The baffle is placed vertically downward from the top wall of grooved channel geometry, with the motive of diverting outside forced flow towards the inside of the ...

  14. Large panel design for containment air baffle

    Science.gov (United States)

    Orr, R.S.

    1992-12-08

    The movable air baffle shield means in accordance with the present invention provides an efficient method of cooling the space surrounding the containment vessel while also providing the capability of being moved away from the containment vessel during inspection. The containment apparatus comprises a generally cylindrical sealed containment vessel for containing at least a portion of a nuclear power generation plant, a disparate shield building surrounding and housing the containment vessel therein and spaced outwardly thereof so as to form an air annulus in the space between the shield building and the containment vessel, a shield baffle means positioned in the air annulus around at least a portion of the sides of the containment vessel providing a coolant path between the baffle means and the containment vessel to permit cooling of the containment vessel by air, the shield baffle means being movable to afford access to the containment vessel. 9 figs.

  15. Large panel design for containment air baffle

    International Nuclear Information System (INIS)

    Orr, R.S.

    1992-01-01

    The movable air baffle shield means in accordance with the present invention provides an efficient method of cooling the space surrounding the containment vessel while also providing the capability of being moved away from the containment vessel during inspection. The containment apparatus comprises a generally cylindrical sealed containment vessel for containing at least a portion of a nuclear power generation plant, a disparate shield building surrounding and housing the containment vessel therein and spaced outwardly thereof so as to form an air annulus in the space between the shield building and the containment vessel, a shield baffle means positioned in the air annulus around at least a portion of the sides of the containment vessel providing a coolant path between the baffle means and the containment vessel to permit cooling of the containment vessel by air, the shield baffle means being movable to afford access to the containment vessel. 9 figs

  16. Liquid metal reactor air cooling baffle

    Science.gov (United States)

    Hunsbedt, A.

    1994-08-16

    A baffle is provided between a relatively hot containment vessel and a relatively cold silo for enhancing air cooling performance. The baffle includes a perforate inner wall positionable outside the containment vessel to define an inner flow riser therebetween, and an imperforate outer wall positionable outside the inner wall to define an outer flow riser therebetween. Apertures in the inner wall allow thermal radiation to pass laterally therethrough to the outer wall, with cooling air flowing upwardly through the inner and outer risers for removing heat. 3 figs.

  17. Evaluation of Double Perforated Baffles Installed in Rectangular Secondary Clarifiers

    Directory of Open Access Journals (Sweden)

    Byonghi Lee

    2017-06-01

    Full Text Available Double perforated baffles in rectangular secondary clarifiers were studied to determine whether they contribute to producing high-quality effluents. The Computational Fluid Dynamics (CFD simulations indicated that bio-flocculation occurred at the front of the baffle and the longitudinal movement of the settled sludge was hampered whenever the clarifier had high inflow. Simulation results showed that the rectangular clarifier with the double perforated baffle produced an effluent with lower suspended solid (SS concentrations than the effluent from the clarifier without the baffle. To verify the simulation results, a double perforated baffle was installed in two of the 48 rectangular clarifiers in a 300,000 m3/d-capacity wastewater treatment plant. To study the effect of the baffle on solid removal, the effluent turbidity of the clarifier with and without the double perforated baffle was measured simultaneously. Experimental data showed that the double perforated baffle played a significant role in reducing effluent turbidity. The effluent turbidity reduction ratio with the baffle decreased when the Sludge Volume Index (SVI of the Mixed Liquor Suspended Solids (MLSS was below 100 mL/g. The overall average reduction ratio was 24.3% for SVI < 100 mL/g and 45.1% for SVI > 100 mL/g. The results of this study suggest that double perforated baffles must be installed in secondary rectangular clarifiers to produce high-quality effluent regardless of the operational conditions.

  18. The baffle influence on sound radiation characteristics of a plate

    Directory of Open Access Journals (Sweden)

    Bao Liu

    2017-01-01

    Full Text Available The acoustic radiation characteristics of the baffle plates and unbaffle plates are calculated and compared by single-layer potential and double-layer potential. Based on the boundary integral equation, the sound pressure integral equation of the baffle and the baffle are deduced respectively. According to the boundary compatibility condition, the sound pressure and the vibration velocity of the plates are obtained. Further, the dynamic equation of the structure is substituted into the vibration equation in the form of the baffle plate and the baffle plate. The sound pressure difference and the displacement of a plate surface are in the form of the vibration mode superposition and the acoustic radiation impedance of the double integral form is obtained, which determines vibration mode coefficient and sound radiation parameters. The effect of the baffle on the acoustic radiation characteristics of the thin plate is analyzed by comparing the acoustic radiation parameters with the simple and simple rectangular plate in water.

  19. Removal of nutrients from septic tank effluent with baffle subsurface-flow constructed wetlands

    Science.gov (United States)

    Lihu Cui; Ying Ouyang; Weizhi Yang; Zhujian Huang; Qiaoling Xu; Guangwei Yu

    2015-01-01

    Three new baffle flow constructed wetlands (CWs), namely the baffle horizontal flow CW (Z1), baffle vertical flow CW (Z2) and baffle hybrid flow CW (Z3), along with one traditional horizontal subsurface flow CW (Z4) were designed to test the removal efficiency of nitrogen (N) and phosphorus (P) from the septic tank effluent under varying hydraulic retention times (HRTs...

  20. Vacuum outgassing from diffuse-absorptive baffle materials

    International Nuclear Information System (INIS)

    Egert, C.M.; Basford, J.A.

    1990-01-01

    Quantitative measurements of outgassing for Martin black and a variety of metallic, diffuse absorptive baffle materials under development for stray light management are reported in this paper. Outgassing measurements were made during pumpdown from atmosphere at room temperature. Mass scans indicate water was the major outgassing species for all materials tested. Calibrated measurements of water vapor outgassing as a function of time were also made for each baffle material. Most baffle materials exhibited total water vapor outgassed during pumpdown of between 1 x 10 -5 and 4 x 10 -5 moles/cm 2 . Plasma sprayed beryllium, currently under development exhibited approximately an order of magnitude lower total water vapor outgassed during pumpdown

  1. Coupling and Shielding Properties of the Baffle in ICP System

    Directory of Open Access Journals (Sweden)

    Jozef Brcka

    2011-01-01

    Full Text Available This contribution is dealing with experimental and computational evaluation of the deposition baffle that is transparent to radio frequency (RF magnetic fields generated by an external antenna in an inductively coupled plasma (ICP source but opaque to the deposition of the metal onto a dielectric wall in ionized physical vapor deposition (IPVD system. Various engineering aspects related to the deposition baffle are discussed. Among the many requirements focus is on specific structure of the slots and analysis to minimize deposition on the baffle (we used a string model for simulating the profile evolution and deposition through the DB on dielectric components of the ICP source. Transparency of the baffle to RF magnetic fields is computed using a three-dimensional (3D electromagnetic field solver. A simple two-dimensional sheath model is used to understand plasma interactions with the DB slot structure. Performance and possible failure of device are briefly discussed.

  2. Stress evaluation of baffle former bolt for IASCC failure prediction

    International Nuclear Information System (INIS)

    Matsubara, T.; Tsutsui, T.; Kamei, Y.; Kitsu, M.

    2011-01-01

    Baffle structure in PWRs Reactor is quite important assembly for the core safety, and Baffle Former Bolts (BFBs) are fastener members for maintaining Baffle structure. It has been reported worldwide that some of BFBs were cracked due to IASCC (Irradiation Assisted Stress Corrosion Cracking) because BFBs are located at core region under severe environments, high neutron flux, high temperature and high stress. According to the material studies of IASCC on austenitic stainless steel, a crack initiation of IASCC is strongly related with the stress and the neutron fluence. For this reason, it is very important for IASCC failure prediction to simulate the stress of BFBs. However, the stress of BFBs are considered to be influenced by several factors and to be changed complexly as operational time increases, by irradiation creep of Bolt itself, swelling of Baffle structure, and so on. Therefore, it is difficult to estimate the stress histories of BFBs (Bolt stress as a function of operational time) precisely. Then, the author has developed the calculation method of the stress histories of BFBs considering irradiation effects (swelling and irradiation creep). In this method, the stress histories of BFBs are calculated by combining two kinds of FE models, Global model (modeled whole Baffle structure which consists of Baffle plates, Former plates and Core Barrel) and Local model (modeled around BFB finely). The whole Baffle structure deformation changes as a function of heat, swelling and irradiated creep are calculated by Global model, and the stress histories of BFBs are calculated by Local model using the outputs (deformations on driving nodes) of Global model. In the FE analysis of Local model, the stress of BFBs are calculated considering irradiation effects and elastic-plastic characteristics depending on neutron fluence, so this method enables to calculate precisely the stress of extreme small area of BFBs surface. This paper shows the outline of the calculation method

  3. Effects of Transverse Baffle Design on Reducing Liquid Sloshing in Partially Filled Tank Vehicles

    Directory of Open Access Journals (Sweden)

    Xue-lian Zheng

    2013-01-01

    Full Text Available Longitudinal liquid sloshing in partially filled clear-bore tanks causes extensive degradation of tankers braking performance. To reduce the negative effect of longitudinal liquid sloshing on tankers, three kinds of transverse baffles were designed, namely, the conventional baffle, the circular baffle, and the staggered baffle. Each kind of baffle took several forms to investigate the impact of baffle installation angle, the sizes of holes pierced on the baffle, and their arrangement on the antisloshing effect. FLUENT software was used to simulate liquid sloshing in tanks equipped with different kinds of transverse baffles and subject to constant braking deceleration. A time-series analysis of the forces act on tank walls and transverse baffles was carried out. It was drawn that the baffle shape and its installation angle have great impact on the antisloshing effect of baffles. The study on the antisloshing effect of different transverse baffles is of great significance for tank vehicle driving and braking safety, as well as for the design of optimal transverse baffles.

  4. Investigation of baffle configuration effect on the performance of exhaust mufflers

    Directory of Open Access Journals (Sweden)

    Ahmed Elsayed

    2017-09-01

    Full Text Available Using baffles in exhaust mufflers is known to improve their transmission loss. The baffle cut ratio should affect the muffler performance analogous to a shell-and-tube heat exchanger. To the authors’ knowledge, there is no previous assessment reported in literature of the effects that the baffle cut ratio configuration has on acoustic response and back pressure. This investigation presents a parametric study on the effect of baffle configuration on transmission loss and pressure drop predicted. The effect of (i the baffle cut ratio and baffle spacing, (ii the number of baffle holes, and (iii the hole distribution for their effect on transmission loss was investigated. Results show that decreasing the baffle cut ratio tends to increase the transmission loss at intermediate frequencies by up to 45%. Decreasing the spacing between muffler plates was shown to enhance the muffler transmission loss by 40%. To assess the baffle effect on flow, the OpenFoam CFD libraries were utilized using the thermal baffle approach model. Baffles were found to cause sudden drop in fluid temperature in axial flow direction. The outlet exhaust gases temperature was found to decrease by 15% as the baffle cut ratio changed from 75% to 25%.

  5. The anaerobic baffled reactor (ABR): An appropriate technology for ...

    African Journals Online (AJOL)

    This project has studied the appropriateness of the ABR for on-site primary sanitation in low-income communities. The baffled design of the ABR ensures high solids retention resulting in high treatment rates, while the overall sludge production is characteristically low. Effluent COD values measured from a 3 000 l pilot ABR ...

  6. The developments of anaerobic baffled reactor for wastewater ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-03-15

    Mar 15, 2010 ... Key words: Anaerobic baffled reactor, anaerobic process, reactor development, performance, solids retention, full-scale. INTRODUCTION. With the ... erobic reactors for the treatment of wastewater. As one of the high-rate anaerobic reactors, the ABR was extensively used in treating wastewater. The ABR ...

  7. The effect of anaerobic baffled reactor effluent on nitrogen and ...

    African Journals Online (AJOL)

    Leaching of nitrogen and phosphorus from soil columns during application of anaerobic baffled reactor effluent was evaluated. The soils used were from Inanda (Ia), Cartref (Cf), and Sepane (Se) forms, and a silica sand (SS). Each was packed into duplicate columns (103 mm internal diameter; 200 mm length), four each for ...

  8. The effect of anaerobic baffled reactor effluent on nitrogen and ...

    African Journals Online (AJOL)

    One of the low-cost sanitation technologies that has been successfully used in developing countries such as Indonesia. (Malisie, 2008; Reynaud et al., 2009) and India (Eales, 2012) is the decentralized wastewater treatment system that incorporates an anaerobic baffled reactor (ABR). The ABR effluent, and nota-.

  9. A Waveguide Transverse Broad Wall Slot Radiating Between Baffles

    DEFF Research Database (Denmark)

    Dich, Mikael; Rengarajan, S.R.

    1997-01-01

    An analysis of the self impedance of waveguide-fed transverse slots radiating between baffles is presented. The region exterior to the slot is treated as a parallel plate (PP) waveguide which radiates into half space through an aperture in an infinite ground plane. The slot problem is analyzed...

  10. Outlet baffles: Effect on liquid residuals from zero-gravity draining of hemispherically ended cylinders

    Science.gov (United States)

    Symons, E. P.

    1972-01-01

    An experimental investigation was conducted to study the relative effectiveness of various outlet baffles in reducing liquid residuals resulting from the draining of hemispherically ended cylindrical tanks in a weightless environment. Three different baffles were employed. The relative effectiveness of each baffle was determined by comparing the results obtained, in the form of liquid residuals, with results for an unbaffled tank. Data indicate that all the baffles tested reduced residuals. Reductions betweem 10 and 60 percent were obtained, depending on baffle geometry and outlfow Weber number.

  11. Estimation of material degradation of VVER-1000 baffle

    Science.gov (United States)

    Harutyunyan, Davit; Koš'ál, Michal; Vandlík, Stanislav; Hojná, Anna; Schulc, Martin; Flibor, Stanislav

    2017-09-01

    The planned lifetime of the first commercial VVER-1000 units were designed for 30 to 35 years. Most of the early VVER plants are now reaching and/or passing the 35-year mark. Service life extension for another 10 to 30 years is now under investigation. Life extension requires the evaluation of pressure vessel internals degradation under long-term irradiation. One of the possible limiting factors for the service life of VVERs is a void swelling of the Russian type titanium stabilized stainless 08Ch18N10T steel used to construct the baffle surrounding the core. This article aims to show first steps towards deeper analysis of the baffle degradation process and to demonstrate the possibilities of precise calculation and measurements on the VVER-1000 mock-up in LR-0 reactor.

  12. A study of the various baffles used in the Marcoule chimneys and the search for a new model (1961)

    International Nuclear Information System (INIS)

    Chassany, J.; Salaun-Penquer, G.

    1961-01-01

    The baffle placed at the top of a chimney determines the shape of the smoke pall for low exit-velocities. The G. 1 type baffle was studied taking into account the characteristics of its collar: totally hollow - partially hollow - solid; on a ribbed chimney or on a plain chimney. The Pu type baffle was also tested. The search for a new type of baffle was limited to variants of the blade - type baffle: - a porous envelope device; - a cone - shaped device and - a deflector of the cupel type. Only the blade-type baffle was rejected, efficient solutions are proposed using the other types or their combinations. (authors) [fr

  13. Modal radiation patterns of baffled circular plates and membranes

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lehrmann; Hansen, Ole; Thomsen, Erik Vilain

    2014-01-01

    The far field velocity potential and radiation pattern of baffled circular plates and membranes are found analytically using the full set of modal velocity profiles derived from the corresponding equation of motion. The derivation is valid for a plate or membrane subjected to an external excitation...... of a plate with clamped, simply supported, and free edge boundary conditions as well as for the membrane. For all non-axisymmetric modes, the velocity potential along the axis of the radiator is found to be strictly zero. In the long wavelength limit, the radiationpattern of all axisymmetric modes approaches...

  14. Supply of a prototype component for the ITER divertor baffle

    International Nuclear Information System (INIS)

    Bobin-Vastra, I.; Febvre, M.; Schedler, B.; Ploechl, L.; Bouveret, Y.; Cauvin, D.; Raisson, G.; Merola, M.

    2001-01-01

    The ITER divertor baffle is one of the Plasma facing components which are developed in the frame of the ITER concept. The supply consisted in the manufacturing of four panels with four First Wall geometries using macroblock or heat sink+armour concepts. DS-Copper, and CuCrZr were the materials for the heat sink, and CFC or Tungsten Plasma spray were the armour. The panels included two Copper-based tubes each. The final purpose is the comparison of the fabricability of each type and the performances of each panel under heat fluxes

  15. Upflow conversion - Eliminating the potential for baffle jetting at McGuire

    Energy Technology Data Exchange (ETDEWEB)

    Kitlan, M.S. Jr.; McClenny, A.M. Jr. (Duke Power Co., Huntersville, NC (United States)); Culp, D.C. (Duke Power Co., Charlotte, NC (United States))

    1991-01-01

    Fuel failures indicative of baffle jetting were observed at Duke Power Company's McGuire units 1 and 2 in 1986 and 1987, respectively. In September 1990 the lower rector internals of unit 2 were modified to permanently eliminate the potential for baffle jetting. The unit 1 internals are to be converted in 1991. McGuire nuclear station is a two-unit, four-loop, Westinghouse pressurized water reactor with 17 by 17 fuel and a gross electrical output of 1,130 MW (electric) per unit. The modification performed on the unit 2 reactor internals resulted in a reversal in the direction of flow through the core barrel and baffle region. This flow reversal reduces the pressure drop across the baffle plates, thus eliminating the driving force for the baffle jets. This modification consists of plugging existing holes in the core barrel and opening new holes in the top former plate to change the flow direction.

  16. Low Frequency Sloshing Analysis of Cylindrical Containers with Flat and Conical Baffles

    Directory of Open Access Journals (Sweden)

    Gnitko V.

    2017-12-01

    Full Text Available This paper presents an analysis of low-frequency liquid vibrations in rigid partially filled containers with baffles. The liquid is supposed to be an ideal and incompressible one and its flow is irrotational. A compound shell of revolution is considered as the container model. For evaluating the velocity potential the system of singular boundary integral equations has been obtained. The single-domain and multi-domain reduced boundary element methods have been used for its numerical solution. The numerical simulation is performed to validate the proposed method and to estimate the sloshing frequencies and modes of fluid-filled cylindrical shells with baffles in the forms of circular plates and truncated cones. Both axisymmetric and non-axisymmetric modes of liquid vibrations in baffled and un-baffled tanks have been considered. The proposed method makes it possible to determine a suitable place with a proper height for installing baffles in tanks by using the numerical experiment.

  17. Modal radiation patterns of baffled circular plates and membranes

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lehrmann; Hansen, Ole; Thomsen, Erik Vilain

    2014-01-01

    force, which is used as a sound receiver in any medium or as a sound transmitter in a gaseous medium. A general, concise expression is given for the radiation pattern of any mode of the membrane and the plate with arbitrary boundary conditions. Specific solutions are given for the four special cases......The far field velocity potential and radiation pattern of baffled circular plates and membranes are found analytically using the full set of modal velocity profiles derived from the corresponding equation of motion. The derivation is valid for a plate or membrane subjected to an external excitation...... of a plate with clamped, simply supported, and free edge boundary conditions as well as for the membrane. For all non-axisymmetric modes, the velocity potential along the axis of the radiator is found to be strictly zero. In the long wavelength limit, the radiationpattern of all axisymmetric modes approaches...

  18. Aeroelastic Dynamics Simulation of Two BaffleBased Connected Shells

    Directory of Open Access Journals (Sweden)

    G. A. Shcheglov

    2015-01-01

    Full Text Available The present work is an extention study of aeroelastic vibrations of thin-walled structures with a spatial subsonic flow. An original algorithm for solving complex conjugated aeroelasticity problem, allowing to carry out direct numerical simulation of structural oscillations in the spatial flow of an incompressible medium are developed and tested. On the basis of this simulation study of the spectrum comes the driving forces acting on the flow in a spatial component elastic structure mounted on an impenetrable screen.Currently, updating the mathematical models of unsteady loads that act on the spacepurpose elastic designs such as launch vehicles, service tower installed on the launch pad is a challenge. We consider two thin-walled cantilevered rotating shells connected by a system of elastic couplings, installed next to the impenetrable baffle so that the axes of rotation are perpendicular to the baffle. Dynamics of elastic system is investigated numerically, using the vortex element method with the spatial separated flow of an incompressible medium. A feature of the algorithm is the common commercial complex MSC Patran / Nastran which is used in preparing data to calculate the shell dynamics thereby allowing to consider very complex dynamic schemes.The work performs the first calculations of the model problem concerning the forced oscillations of two coupled cylindrical shells in the flow of an incompressible medium. Comparing the load spectra for the elastic and absolutely rigid structure has shown that the frequency spectra vary slightly. Further calculations are required in which it will be necessary to increase the duration of the calculations, sampling in construction of design scheme, and given the large number of vibration modes that require increasing computing power.Experience in calculating aeroelastic dynamics of complex elastic structures taking into account the screen proved to be successful as a whole, thereby allowing to turn to

  19. Wastewater treatment in a hybrid activated sludge baffled reactor

    International Nuclear Information System (INIS)

    Tizghadam, Mostafa; Dagot, Christophe; Baudu, Michel

    2008-01-01

    A novel hybrid activated sludge baffled reactor (HASBR), which contained both suspended and attached-growth biomass perfect mixing cells in series, was developed by installing standing and hanging baffles and introducing plastic brushes into a conventional activated sludge (CAS) reactor. It was used for the treatment of domestic wastewater. The effects on the operational performance of developing the suspended and attached-growth biomass and reactor configuration were investigated. The change of the flow regime from complete-mix to plug-flow, and the addition of plastic brushes as a support for biofilm, resulted in considerable improvements in the COD, nitrogen removal efficiency of domestic wastewater and sludge settling properties. In steady state, approximately 98 ± 2% of the total COD and 98 ± 2% of the ammonia of the influent were removed in the HASBR, when the influent wastewater concentration was 593 ± 11 mg COD/L and 43 ± 5 mg N/L, respectively, at a HRT of 10 h. These results were 93 ± 3 and 6 ± 3% for the CAS reactor, respectively. Approximately 90 ± 7% of the total COD was removed in the HASBR, when the influent wastewater concentration was 654 ± 16 mg COD/L at a 3 h HRT, and in the organic loading rate (OLR) of 5.36 kg COD m -3 day -1 . The result for the CAS reactor was 60 ± 3%. Existing CAS plants can be upgraded by changing the reactor configuration and introducing biofilm support media into the aeration tank

  20. Wastewater treatment in a hybrid activated sludge baffled reactor.

    Science.gov (United States)

    Tizghadam, Mostafa; Dagot, Christophe; Baudu, Michel

    2008-06-15

    A novel hybrid activated sludge baffled reactor (HASBR), which contained both suspended and attached-growth biomass perfect mixing cells in series, was developed by installing standing and hanging baffles and introducing plastic brushes into a conventional activated sludge (CAS) reactor. It was used for the treatment of domestic wastewater. The effects on the operational performance of developing the suspended and attached-growth biomass and reactor configuration were investigated. The change of the flow regime from complete-mix to plug-flow, and the addition of plastic brushes as a support for biofilm, resulted in considerable improvements in the COD, nitrogen removal efficiency of domestic wastewater and sludge settling properties. In steady state, approximately 98+/-2% of the total COD and 98+/-2% of the ammonia of the influent were removed in the HASBR, when the influent wastewater concentration was 593+/-11 mg COD/L and 43+/-5 mg N/L, respectively, at a HRT of 10 h. These results were 93+/-3 and 6+/-3% for the CAS reactor, respectively. Approximately 90+/-7% of the total COD was removed in the HASBR, when the influent wastewater concentration was 654+/-16 mg COD/L at a 3h HRT, and in the organic loading rate (OLR) of 5.36kgCOD m(-3) day(-1). The result for the CAS reactor was 60+/-3%. Existing CAS plants can be upgraded by changing the reactor configuration and introducing biofilm support media into the aeration tank.

  1. Numerical study of double-diffusive convection in a vertical annular enclosure with a baffle

    Science.gov (United States)

    Pushpa, B. V.; Prasanna, B. M. R.; Younghae, Do; Sankar, M.

    2017-10-01

    This paper numerically examines the influence of a circular thin baffle on thermosolutal convection in a vertical annular enclosure. The inner and outer cylindrical walls, and the baffle are retained with different temperatures and concentrations, while the upper and lower boundaries are kept at adiabatic and impermeable. The model equations are solved using an implicit finite difference scheme consisting of ADI and SLOR methods. Numerical simulations are performed to understand the size and position effects of the baffle on the thermosolutal convection and are successfully captured through our results. It has been observed that the baffle size and location has very important role in controlling the thermosolutal convective flow and the corresponding heat and mass transport characteristics. Further, our results are in good agreement with the available benchmark results for limiting cases.

  2. Numerical Simulation of Sloshing Phenomena in Cubic Tank with Multiple Baffles

    Directory of Open Access Journals (Sweden)

    Mi-An Xue

    2012-01-01

    Full Text Available A two-phase fluid flow model solving Navier-Stokes equations was employed in this paper to investigate liquid sloshing phenomena in cubic tank with horizontal baffle, perforated vertical baffle, and their combinatorial configurations under the harmonic motion excitation. Laboratory experiment of liquid sloshing in cubic tank with perforated vertical baffle was carried out to validate the present numerical model. Fairly good agreements were obtained from the comparisons between the present numerical results and the present experimental data, available numerical data. Liquid sloshing in cubic tank with multiple baffles was investigated numerically in detail under different external excitation frequencies. Power spectrum of the time series of free surface elevation was presented with the aid of fast Fourier transform technique. The dynamic impact pressures acting on the normal and parallel sidewalls were discussed in detail.

  3. Treatment of a textile dye in the anaerobic baffled reactor | Bell ...

    African Journals Online (AJOL)

    scale anaerobic baffled reactor (ABR). The results of the physical decolorisation tests suggested significant decolorisation due to adsorption to the biomass; however, it is possible that the dye chromophores were reduced due to the low redox ...

  4. Development of a model for baffle energy dissipation in liquid fueled rocket engines

    Science.gov (United States)

    Miller, Nathan A.

    In this thesis the energy dissipation from a combined hub and blade baffle structure in a combustion chamber of a liquid-fueled rocket engine is modeled and computed. An analytical model of the flow stabilization due to the effect of combined radial and hub blades was developed. The rate of energy dissipation of the baffle blades was computed using a corner-flow model that included unsteady flow separation and turbulence effects. For the inviscid portion of the flow field, a solution methodology was formulated using an eigenfunction expansion and a velocity potential matching technique. Parameters such as local velocity, elemental path length, effective viscosity, and local energy dissipation rate were computed as a function of the local angle alpha for a representative baffle blade, and compared to results predicted by the Baer-Mitchell blade dissipation model. The sensitivity of the model to the overall engine acoustic oscillation mode, blade length, and thickness was also computed and compared to previous results. Additional studies were performed to determine the sensitivity to input parameters such as the dimensionless turbulence coefficient, the location of the potential difference in the generation of the dividing streamline, the number of baffle blades and the size of the central hub. Stability computations of a test engine indicated that when the baffle length is increased, the baffles provide increased stabilization effects. The model predicts greatest dissipation for radial modes with a hub radius at approximately half the chamber's radius.

  5. Pretreatment of textile dyeing wastewater using an anoxic baffled reactor.

    Science.gov (United States)

    Kong, Huoliang; Wu, Huifang

    2008-11-01

    A study on pretreatment of textile dyeing wastewater was carried out using an anoxic baffled reactor (ABR) at wastewater temperatures of 5-31.1 degrees C. When hydraulic retention time (HRT) was 8h, the color of outflow of ABR was only 40 times at 5 degrees C and it could satisfy the professional discharge standard (grade-1) of textile and dyeing industry of China (GB4287-92). The total COD removal efficiency of ABR was 34.6%, 47.5%, 50.0%, 53.3%, 54.7% and 58.1% at 5, 9.7, 14.9, 19.7, 23.5 and 31.1 degrees C, respectively. Besides, after the wastewater being pre-treated by ABR when HRT was 6h and 8h, the BOD5/COD value rose from 0.30 of inflow to 0.46 of outflow and from 0.30 of inflow to 0.40 of outflow, respectively. Experimental results indicated that ABR was a very feasible process to decolorize and pre-treat the textile dyeing wastewater at ambient temperature. Moreover, a kinetic simulation of organic matter degradation in ABR at six different wastewater temperatures was carried through. The kinetic analysis showed the organic matter degradation was a first-order reaction. The reaction activation energy was 19.593 kJ mol(-1) and the temperature coefficient at 5-31.1 degrees C was 1.028.

  6. Multi-phased anaerobic baffled reactor treating food waste.

    Science.gov (United States)

    Ahamed, A; Chen, C-L; Rajagopal, R; Wu, D; Mao, Y; Ho, I J R; Lim, J W; Wang, J-Y

    2015-04-01

    This study was conducted to identify the performance of a multi-phased anaerobic baffled reactor (MP-ABR) with food waste (FW) as the substrate for biogas production and thereby to promote an efficient energy recovery and treatment method for the wastes with high organic solid content through phase separation. A four-chambered ABR was operated at an HRT of 30 days with an OLR of 0.5-1.0 g-VS/Ld for a period of 175 days at 35 ± 1°C. Consistent overall removal efficiencies of 85.3% (CODt), 94.5% (CODs), 89.6% (VFA) and 86.4% (VS) were observed throughout the experiment displaying a great potential to treat FW. Biogas generated was 215.57 mL/g-VS removed d. Phase separation was observed and supported by the COD and VFA trends, and an efficient recovery of bioenergy from FW was achieved. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Modal radiation patterns of baffled circular plates and membranes.

    Science.gov (United States)

    Christiansen, Thomas Lehrmann; Hansen, Ole; Thomsen, Erik Vilain; Jensen, Jørgen Arendt

    2014-05-01

    The far field velocity potential and radiation pattern of baffled circular plates and membranes are found analytically using the full set of modal velocity profiles derived from the corresponding equation of motion. The derivation is valid for a plate or membrane subjected to an external excitation force, which is used as a sound receiver in any medium or as a sound transmitter in a gaseous medium. A general, concise expression is given for the radiation pattern of any mode of the membrane and the plate with arbitrary boundary conditions. Specific solutions are given for the four special cases of a plate with clamped, simply supported, and free edge boundary conditions as well as for the membrane. For all non-axisymmetric modes, the velocity potential along the axis of the radiator is found to be strictly zero. In the long wavelength limit, the radiation pattern of all axisymmetric modes approaches that of a monopole, while the non-axisymmetric modes exhibit multipole behavior. Numerical results are also given, demonstrating the implications of having non-axisymmetric excitation using both a point excitation with varying eccentricity and a homogeneous excitation acting on half of the circular radiator.

  8. Complete resolution of systemic venous baffle obstruction and baffle leak using the Gore Excluder covered stent in two patients with transposition of the great arteries and prior Mustard procedure.

    Science.gov (United States)

    Hill, Kevin D; Fudge, J Curt; Rhodes, John F

    2010-11-15

    We present two patients with a history of Mustard repair of transposition of the great arteries. Both patients presented with exertional limitation and demonstrated superior systemic venous baffle obstruction as well as multiple baffle leaks. In both patients stent relief of obstruction and baffle leak exclusion was accomplished using a combination of bare metal stents and the aortic extension portion of the Gore Excluder covered stent (W.L. Gore and Associates, Flagstaff, Arizona). Copyright © 2010 Wiley-Liss, Inc.

  9. Energy efficiency improvement and fuel savings in water heaters using baffles

    International Nuclear Information System (INIS)

    Moeini Sedeh, Mahmoud; Khodadadi, J.M.

    2013-01-01

    Highlights: ► Thermal efficiency improved by simple/novel design of baffles inside water reservoir. ► Noticeable steady-state natural gas savings of about 5%. ► Extensive 3-D numerical investigations followed by experimental verifications. ► Baffle designs prototyped in identical water heaters for ANSI/US DOE test protocols. ► Numerical/experimental results verified thermal efficiency improvement and fuel savings. -- Abstract: Thermal efficiency improvement of a water heater was investigated numerically and experimentally in response to presence of a baffle, particularly designed for modifying the flow field within the water reservoir and enhancing heat transfer extracted into the water tank. A residential natural gas-fired water heater was selected for modifying its water tank through introducing a baffle for lowering natural gas consumption by 5% as a target. Based on the geometric features of the selected water heater, three-dimensional models of the water heater subsections were developed. Upon detailed studies of flow and heat transfer in each subsection, various sub-models were integrated to a complete model of the water heater. Thermal performance of the selected water heater was investigated numerically using computational fluid dynamics analysis. Prior to baffle design process and in order to verify the developed model of the water heater, time-dependent numerically-predicted temperatures were compared to the experimentally-measured temperatures under the same conditions at six (6) different locations inside the water tank and good agreement was observed. Upon verifying the numerical model, the fluid flow and heat transfer patterns were characterized for the selected water heater. The overall design of the baffle and its location and orientation were finalized based on the numerical results and a set of parametric studies. Finally, two baffle designs were proposed, with the second design being an optimized version of the first design. The

  10. Validity of Miles Equation in Predicting Propellant Slosh Damping in Baffled Tanks at Variable Slosh Amplitude

    Science.gov (United States)

    Yang, H. Q.; West, Jeff

    2018-01-01

    Determination of slosh damping is a very challenging task as there is no analytical solution. The damping physics involves the vorticity dissipation which requires the full solution of the nonlinear Navier-Stokes equations. As a result, previous investigations were mainly carried out by extensive experiments. A systematical study is needed to understand the damping physics of baffled tanks, to identify the difference between the empirical Miles equation and experimental measurements, and to develop new semi-empirical relations to better represent the real damping physics. The approach of this study is to use Computational Fluid Dynamics (CFD) technology to shed light on the damping mechanisms of a baffled tank. First, a 1-D Navier-Stokes equation representing different length scales and time scales in the baffle damping physics is developed and analyzed. Loci-STREAM-VOF, a well validated CFD solver developed at NASA MSFC, is applied to study the vorticity field around a baffle and around the fluid-gas interface to highlight the dissipation mechanisms at different slosh amplitudes. Previous measurement data is then used to validate the CFD damping results. The study found several critical parameters controlling fluid damping from a baffle: local slosh amplitude to baffle thickness (A/t), surface liquid depth to tank radius (d/R), local slosh amplitude to baffle width (A/W); and non-dimensional slosh frequency. The simulation highlights three significant damping regimes where different mechanisms dominate. The study proves that the previously found discrepancies between Miles equation and experimental measurement are not due to the measurement scatter, but rather due to different damping mechanisms at various slosh amplitudes. The limitations on the use of Miles equation are discussed based on the flow regime.

  11. Comprehensive study for Anammox process via multistage anaerobic baffled reactors

    Science.gov (United States)

    Ismail, Sherif; Tawfik, Ahmed

    2017-11-01

    Continuous anaerobic ammonia oxidation (Anammox) process in multistage anaerobic baffled (MABR) reactor was investigated. The reactor was operated for approximately 150 days at constant hydraulic retention time (HRT) of 48 h and was fed with synthetic wastewater containing nitrite and ammonium as main substrates. The MABR was inoculated with mixed culture bacteria collected from activated sludge plant (41.6 g MLSS/L and 19.1 g MLVSS/L). The MABR reactor exhibited excellent performance for the start-up of Anammox process within a period of 35 days. The start-up period was divided into four successive phases; cell lysis, lag, activity elevation and steady state. Total inorganic nitrogen (TIN) removal efficiency of 96.8± 0.9% was achieved at steady state conditions, corresponding to nitrogen removal rate (NRR) of 50.2±1.7 mg N/L·d. Moreover, the effect of HRT on the Anammox process was assessed with applying five different HRTs of (48, 38.4, 28.8, 19.2 and 9.6 h). Decreasing HRT from 48 to 9.6 h reduced the removal efficiencies of NH4-N, NO2-N and TIN from 97.7±2.2 to 49.0±9.8%, from 95.7±1.9 to 71.0±8.5% and from 96.8±0.9 to 57.9±9.1%, respectively, that corresponding to reduction in NRR from 50.8±1.2 mg N/L·d at HRT of 48 h to 32.5±5.0 mg N/L·d at HRT of 9.6 h.

  12. Comprehensive study for Anammox process via multistage anaerobic baffled reactors

    Directory of Open Access Journals (Sweden)

    Ismail Sherif

    2017-01-01

    Full Text Available Continuous anaerobic ammonia oxidation (Anammox process in multistage anaerobic baffled (MABR reactor was investigated. The reactor was operated for approximately 150 days at constant hydraulic retention time (HRT of 48 h and was fed with synthetic wastewater containing nitrite and ammonium as main substrates. The MABR was inoculated with mixed culture bacteria collected from activated sludge plant (41.6 g MLSS/L and 19.1 g MLVSS/L. The MABR reactor exhibited excellent performance for the start-up of Anammox process within a period of 35 days. The start-up period was divided into four successive phases; cell lysis, lag, activity elevation and steady state. Total inorganic nitrogen (TIN removal efficiency of 96.8± 0.9% was achieved at steady state conditions, corresponding to nitrogen removal rate (NRR of 50.2±1.7 mg N/L·d. Moreover, the effect of HRT on the Anammox process was assessed with applying five different HRTs of (48, 38.4, 28.8, 19.2 and 9.6 h. Decreasing HRT from 48 to 9.6 h reduced the removal efficiencies of NH4-N, NO2-N and TIN from 97.7±2.2 to 49.0±9.8%, from 95.7±1.9 to 71.0±8.5% and from 96.8±0.9 to 57.9±9.1%, respectively, that corresponding to reduction in NRR from 50.8±1.2 mg N/L·d at HRT of 48 h to 32.5±5.0 mg N/L·d at HRT of 9.6 h.

  13. Carbon and nitrogen removal in a granular bed baffled reactor.

    Science.gov (United States)

    Baloch, M I; Akunna, J C; Collier, P J

    2006-02-01

    The application of an anaerobic five compartment granular bed baffled reactor (GRABBR) was investigated with brewery wastewater for combined carbon and nitrate removal, with a separate downstream nitrification unit for converting ammonia to nitrate. The GRABBR was operated at an organic loading rate of 3.57 kg chemical oxygen demand (COD) m(-3) d(-1) and ammoniacal nitrogen (NH4-N) loading rate of 0.13 kg NH4-N m(-3) d(-1) when nitrified effluent from a downstream nitrification unit was recycled to the feed point of the GRABBR. Carbonaceous matter and nitrate were removed simultaneously in the GRABBR at different recycle to influent ratios (from 1 to 2), with nitrogen oxide (nitrate and nitrite nitrogen, NOx-N) loading rates varying from 0.04 to 0.05 kg NOx-N m(-3) d(-1). At all recycle to influent ratios, COD removal efficiency of 97% to 98% were observed in the GRABBR, and over 99% by the two-stage treatment configuration (i.e. GRABBR and nitrification unit). All the nitrates added to the GRABBR were denitrified in the first three compartments of the system. For all the recycle to influent ratios studied, almost all ammonia was converted to nitrate nitrogen with only small traces of nitrite nitrogen in the nitrification unit. Methane production was observed throughout the experimental period with its composition varying from 25% to 50%, showing that simultaneous methanogenesis and denitrification occurred. This study shows that a GRABBR could bring about a high degree of carbon and nitrate removal, with simultaneous methanogenesis and denitrification, due to plug flow granular bed multi-stage characteristics of the bioreactor.

  14. Effect of baffles on the hydraulic performance of sediment retention ponds.

    Science.gov (United States)

    Khan, Sher; Melville, Bruce W; Khan, Mudasser Muneer; Shoaib, Muhammad; Shamseldin, Asaad

    2017-05-01

    An investigation of the effect of baffles on retention pond performance using a physical model of an existing sediment retention pond is presented. Analysis of residence time (RTD curves) was used to compare the hydraulic performance of different arrangements of baffles in the pond. Five different arrangements for the design of baffles were studied. The results show that placing a single baffle to deflect the influent to a sediment retention pond does not improve pond performance; rather, it stimulates short-circuiting. This is contradictory to the literature and is considered to be a consequence of the model pond incorporating sloping walls, which is a novel aspect of this study. Most of the previous studies have neglected the effects of battered walls. Conversely, the inclusion of more than two baffles was found to increase the hydraulic performance. The results reported here are limited to small and narrow ponds where a large portion of the pond is batter (i.e. made up of sloping walls). For large area ponds, batter effects may be negligible and are likely to be different from those reported here.

  15. Vibro-impact responses of a tube with tube--baffle interaction

    International Nuclear Information System (INIS)

    Shin, Y.S.; Sass, D.E.; Jendrzejczyk, J.A.

    1978-01-01

    The relatively small, inherent tube-to-baffle hole clearances associated with manufacturing tolerances in heat exchangers affect the vibrational characteristics and the response of the tube. Numerical studies were made to predict the vibro-impact response of a tube with tube-baffle interaction. The finite element method has been employed with a non-linear elastic contact spring-dashpot to model the effect of the relative approach between the tube and the baffle plate. The coupled equations of motion are directly integrated with a proportional system damping represented by a linear combination of mass and stiffness. Lumped mass approach with explicit time integration scheme was found to be a suitable choice for tube-baffle impacting analysis. Fourier analyses indicate that the higher mode contributions to the tube response are significant for strong tube-baffle impacting. The contact damping forces are negligible compared with the contact spring forces. The numerical analysis results are in reasonably good agreement with those of the experiments

  16. Microfluidic characteristics of a multi-holed baffle plate micro-reactor

    International Nuclear Information System (INIS)

    Moghtaderi, Behdad; Shames, Iman; Djenidi, L.

    2006-01-01

    As part of a larger project aiming at development of a miniaturized hydrogen generator for small mobile/onboard fuel cell applications, a series of experiments was conducted on a novel micro-reactor to examine the effectiveness of its design in promoting the mixing of reactant agents. The reactor is essentially a tubular vessel fitted with a multi-holed baffle plate mounted on a central tube. The mixing phenomenon within the micro-reactor was studied using the micro-PIV (micro-particle image velocimetry) flow visualization technique. Experiments were conducted on a 1:1 scale replica of the reactor. Results indicate that the application of the multi-holed baffle plate considerably improves the mixing performance of the reactor when compared with a simpler co-axial jet tubular reactor. However, the geometrical characteristics of the baffle plate and central tube are found to have dramatic impacts upon the flow structure and mixing patterns within the reactor. Hence, the optimization of the reactor geometry is required to achieve the desirable mixing performance. For the range of Reynolds numbers studied here, the optimum reactor geometry is achieved when the central tube and baffle holes are of similar diameters and baffle holes are located half way between the stream-wise axis and the reactor wall

  17. The baffle-barrel-bolting analysis program: evolution and technical accomplishments

    International Nuclear Information System (INIS)

    Schwirian, R.E.; Forsyth, D.R.; Snyder, M.D.; Bhandari, D.R.; Barsic, J.A.; Rabenstein, W.D.

    2001-01-01

    In Westinghouse pressurized water reactors (PWR) the reactor core is surrounded by baffle plates, which provide lateral restraint for the fuel assemblies at the core boundary. Baffle plates are attached to horizontal supports called former plates by baffle-former bolts. The formers are attached to the core barrel which also provides vertical support for the core. The B3 analysis program addresses the possibility of reduced baffle-former bolting in Westinghouse U.S. domestic plant designs with respect to the relevant design criteria. Since safety is the overriding motivation for the program, faulted events have received the most in-depth attention. This focus has been reinforced by the fact that the loads produced by the loss-of-coolant-accident (LOCA) have usually been the most limiting of all those considered. Consequently, much of the presentation below deals with the development of analysis techniques and acceptance criteria to demonstrate that LOCA-induced loads on the bolts and the fuel assemblies will be acceptable with significantly reduced baffle-former bolting. A discussion of the other faulted, normal, and upset analyses performed as part of the program will also be presented. (author)

  18. Stability of inner baffle-shell of pool type LMFBR - experimental and theoretical studies

    International Nuclear Information System (INIS)

    Lebey, J.; Combescure, A.

    1987-01-01

    I pool type LMFBR, the primary coolant circuit, inside the main vessel, comprises a hot plenum separated from a cold plenum by an inner baffle. For Superphenix 1 reactor, it was judged advisable to built a double-shell baffle, each shell withstanding only one type of loading (primary loading for one shell, secondary loading for the other). Due to the size and intricacy of the structure, this design involves unnegligible supplementary costs and manufacturing difficulties. Thus, an alternative solution has been studied for future plants projects. It consists of a single shell baffle having a shape especially studied to sustain the two types of applied loadings (thermal plus primary loadings). Such a shape was calculated by NOVATOME, and it was decided to check the ability of methods of analysis to predict the ruin of this structure under primary loading. For this purpose, a mock-up has been tested, and the experimental results compared with the calculated ones. (orig./GL)

  19. Optimal design of sandwich ribbed flat baffle plates of a circular cylindrical tank

    International Nuclear Information System (INIS)

    Malinowski, Marek; Magnucki, Krzysztof

    2005-01-01

    The subject of this paper is a sandwich ribbed flat baffle plate of a circular cylindrical tank. The paper deals with a problem of optimal thickness of this construction with a soft core. The construction is distinguished by a local axisymmetric pre-springing. The mathematical description is based on the theory of shells with analysis of disturbance of the stress membrane state. The sandwich ribbed flat baffle plate divides the tank into two chambers. One of them is loaded by uniform pressure, while the other is empty and unloaded. Dimensions of ribs, faces and the entire baffle plate have been determined with a view to minimize the mass under strength constraints. The effect of optimal thickness of this sandwich plate has been examined by means of the finite element method

  20. On the dynamic spatial response of a heat exchanger tube with intermittent baffle contacts

    International Nuclear Information System (INIS)

    Rogers, R.J.; Pick, R.J.

    1976-01-01

    Flow-induced vibration in heat exchanger tubes can result in fretting wear at the baffle supports and subsequent tube failure. As one step in correlating the random flow excitation to the rate of fretting wear, this paper presents a dynamic finite element technique for predicting the motions and baffle contact forces of a single heat exchanger tube. Using a modal superposition approach, the modal equations of motion are generated and numerically integrated. The predicted results are compared with experimental data for both planar and spatial vibration of harmonically excited cantilevered beams with a clearance support at the free end. (Auth.)

  1. Numerical evaluation of acoustic power radiation and radiation efficiencies of baffled plates

    NARCIS (Netherlands)

    Lemmen, R.L.C.; Panuszka, R.J.

    1996-01-01

    In this paper expressions are given for the numerical evaluation of radiation efficiencies and power radiation of baffled plates. The expressions can be used as a postprocessing tool in the Finite Element Method. Numerical results for simply supported plates are presented and compared with results

  2. A Computational Fluid Dynamics Study of Swirling Flow Reduction by Using Anti-Vortex Baffle

    Science.gov (United States)

    Yang, H. Q.; Peugeot, John W.; West, Jeff S.

    2017-01-01

    An anti-vortex baffle is a liquid propellant management device placed adjacent to an outlet of the propellant tank. Its purpose is to substantially reduce or eliminate the formation of free surface dip and vortex, as well as prevent vapor ingestion into the outlet, as the liquid drains out through the flight. To design an effective anti-vortex baffle, Computational Fluid Dynamic (CFD) simulations were undertaken for the NASA Ares I vehicle LOX tank subjected to the simulated flight loads with and without the anti-vortex baffle. The Six Degree-Of-Freedom (6-DOF) dynamics experienced by the Crew Launch Vehicle (CLV) during ascent were modeled by modifying the momentum equations in a CFD code to accommodate the extra body forces from the maneuvering in a non-inertial frame. The present analysis found that due to large moments, the CLV maneuvering has a significant impact on the vortical flow generation inside the tank. Roll maneuvering and side loading due to pitch and yaw are shown to induce swirling flow. The vortical flow due to roll is symmetrical with respect to the tank centerline, while those induced by pitch and yaw maneuverings showed two vortices side by side. The study found that without the anti-vortex baffle, the swirling flow caused surface dip during the late stage of drainage and hence early vapor ingestion. The flow can also be non-uniform in the drainage pipe as the secondary swirling flow velocity component can be as high as 10% of the draining velocity. An analysis of the vortex dynamics shows that the swirling flow in the drainage pipe during the Upper Stage burn is mainly the result of residual vortices inside the tank due to the conservation of angular momentum. The study demonstrated that the swirling flow in the drainage pipe can be effectively suppressed by employing the anti-vortex baffle.

  3. An experimental study of heat transfer enhancement in an air channel with broken multi type V-baffles

    Science.gov (United States)

    Kumar, Anil; Kumar, Raj; Maithani, Rajesh; Chauhan, Ranchan; Kumar, Sushil; Nadda, Rahul

    2017-12-01

    This work aims at studying the effect of broken multi type V-baffles on heat transfer, pressure drop, and thermal hydraulic performance characteristics in an air channel is experimentally investigated. The air channel had aspect ratio of 10.0 and the Reynolds number (Re) based upon the mass flow rate of air ( m a ) at entrance of the channel varied from 3000 to 8000. The discrete baffle distance ( D d / L v ) varied from 0.27 to 0.77, relative baffle gap width ( G w / H B ) varied from 0.50 to 1.5, relative baffle height ( H B / H D ) varied from 0.25 to 1.0, relative baffle pitch ( P B / H B ) varied from 8.0 to 12, relative baffle width ( W D / H D ) varied from 1.0 to 6.0, and flow attack angle ( α a )varied from 30° to 70°. It has been found that performance of broken multi type V-baffles air channel is better than the performance of smooth surface air channel for the range of geometrical parameters investigated. Experimental results observed that maximum enhancement in overall thermal performance have been found at Dd/Lv value of 0.67, Gw/HB value of 1.0, HB/HD value of 0.50, P B / H B value of 10, and αavalue of 60°.

  4. Studi Numerik Pengaruh Baffle Inclination Pada Alat Penukar Kalor Tipe Shell And Tube Terhadap Aliran Fluida Dan Perpindahan Panas

    Directory of Open Access Journals (Sweden)

    Rezky Fadil Arnaw

    2014-09-01

    Full Text Available Heat exchanger atau alat penukar kalor merupakan suatu peralatan yang digunakan untuk memindahkan sejumlah energi dalam bentuk panas dari satu fluida ke fluida yang lain. Perpindahan panas tersebut terjadi dari suatu fluida yang suhunya lebih tinggi ke fluida lain yang suhunya lebih rendah. Pada tugas akhir ini akan dilakukan penelitian tentang pengaruh baffle inclination terhadap aliran fluida dan perpindahan panas pada alat penukar kalor tipe shell and tube. Dalam penelitian ini akan dilakukan tiga variasi sudut baffle inclination yaitu 0º, 10° dan 20° dengan besar laju aliran massa yang divariasikan yaitu sebesar 0.5 kg/s, 1 kg/s dan 2 kg/s. Tipe baffle yang digunakan adalah single segmental baffle dengan baffle cut sebesar 36% dan menggunakan arah aliran jenis parallel. Hasil analisa simulasi menunjukkan bahwa laju aliran massa yang meningkat akan menyebabkan kenaikan pressure drop yang cukup drastis dan penurunan temperatur outlet. Alat penukar kalor dengan baffle inclination 0° memiliki nilai perpindahan panas terbaik jika dibandingkan dengan baffle inclination 10° dan 20°.

  5. Studi Numerik Pengaruh Baffle Inclination Pada Alat Penukar Kalor Tipe U – Tube Terhadap Aliran Fluida Dan Perpindahan Panas

    Directory of Open Access Journals (Sweden)

    Reza Hidayatullah

    2014-09-01

    Full Text Available Alat penukar kalor sangat berpengaruh dalam industri terhadap keberhasilan keseluruhan rangkaian proses, karena kegagalan operasi alat ini baik akibat kegagalan mekanikal maupun opersional dapat menyebabkan berhentinya operasi unit. Penelitian terhadap desain heat exchanger masih terus dilakukan untuk mencari kinerja dari heat exchanger yang paling optimal, baik pada bagian baffle cut dan baffles inclination maupun susunan dari tube dengan menggunakan heat exchanger ukuran kecil sebagai model. Berdasarkan pada permasalahan di atas, maka dilakukan penelitian terhadap kinerja heat exchanger tipe U-tube dengan memvariasikan baffle inclination. Penelitian ini dilakukan secara numerik dengan variasi baffle inclination sebesar 0o, 10o, 20o dan variasi laju aliran massa sebesar 0,5 kg/s, 1kg/s, dan 2 kg/s. Tube yang digunakan adalah tipe U-tube yang disusun secara persegi. Model viskous yang digunakan adalah turbulensi model yaitu k-ε standar, dimana fluida yang digunakan adalah air pada boundary condition. Hasil analisa numerik menunjukkan adanya pengaruh baffle inclination pada alat penukar kalor tipe U – tube terhadap aliran fluida dan perpindahan panas. Peningkatan laju aliran massa dapat meningkatkan pressure drop secara cepat, alat penukar kalor shell and tube tipe U – tube dengan baffle inclination 20o memiliki unjuk kerja yang terbaik dibandingkan dengan baffle inclination 0o dan 10o.

  6. Numerical and experimental investigation on the baffle design in secondary side of the PRHR HX in AP1000

    International Nuclear Information System (INIS)

    Lu, Daogang; Zhang, Yuhao; Wang, Zhongyi; Fu, Xiaoliang; Yang, Yanhua; Cao, Qiong

    2016-01-01

    Highlights: • Four baffles designs are put forward to reduce thermal stratification in IRWST. • Different influencing factors are studied by both numerical and experimental methods. • The beneficial and deleterious factors combine to determine the overall HTC in baffle design. • It provides possible improvement ways for the optimization of the PRHR HX design. - Abstract: The effective and reliable operation of the Passive Residual Heat Removal System (PRHRS) is very significant for the safety of the reactor. However, the passive heat sink tank IRWST in PRHRS is vulnerable to get stratified, which has deleterious impacts on the heat transfer effect of the Passive Residual Heat Removal Heat Exchanger (PRHR HX). In the present work, both the numerical simulations and experiments are conducted to investigate the passive baffles designs of the PRHR HX&IRWST. An overall scaled-down separate-effects PRHR HX&IRWST experimental test bench has been built, and the experimental data are used to validate the numerical methods in the prototype PRHR HX model. Different passive baffles Designs A–D are tested employing the commercial CFD software CFX, and then validated by the baffles experiment. The influencing factors of baffles number, thermal conductivity, and baffles shape are investigated. Both the numerical and experimental temperature distributions, natural convection velocity, thermal stratification extent, as well as the Heat Transfer Coefficient are analyzed. The complicated factors combine to determine the overall HTC in baffle design. The numerical and experimental results provide possible improvement ways for the optimization of the PRHR HX baffles design, which have practical engineering application significance in the optimum design of the passive safe system in AP1000 plant.

  7. Determination of in-service change in the geometry of WWER-1000 core baffle: Calculations and measurements

    International Nuclear Information System (INIS)

    Margolin, B.Z.; Varovin, A.Y.; Minkin, A.J.; Sorokin, A.A.; Piminov, V.A.; Evdokimenko, V.V.; Fedosovsky, M.E.; Sherstobitov, A.E.; Ovchinnikov, A.G.; Pikulik, S.S.; Erak, D.Y.; Bobkov, A.V.; Timofeev, A.M.; Timokhin, V.I.; Yakushev, S.V.; Vasiliev, V.G.

    2015-01-01

    The paper gives the basic constitutive equations describing radiation swelling and creep depending on neutron dose, irradiation temperature and triaxial stress state, and justifies these equations experimentally. The WWER-1000 core baffle change in geometry was calculated by different models describing the effect of stresses on radiation swelling. The calculated results are compared with the measured ones for the operating WWER-1000 core baffle at the Balakovo NPP, Unit 1. A method of individual prediction of core baffle geometry change on the basis of the measurement results has been proposed. (authors)

  8. Experimental study on curve-baffle characteristics of pneu-pin sensor with differential pressure

    Science.gov (United States)

    Wang, Fengwei; Zhang, Hui; Deng, Shanxi; Zeng, Hanping

    2008-10-01

    This paper presents the design and working principle of a pneu-pin sensor based on a gas path with differential pressure, and the study on its curve-baffle characteristics. The measurement range of the sensor is about 32 μm, with a resolution of 0.03 μm and less than an uncertainty of 0.3 μm. It is found through research on the curve-baffle characteristics with different curvature radius of steel balls that the axis of the pneumatic probe does not need to go through the geometric centre of work-piece, and so, the high accuracy positioning of the work-piece is avoided. Therefore, the pneumatic measurement technology researched in this paper can be applied to high accuracy non-contact dimension of measurement of different curvature radius of work-pieces.

  9. Ultrasonic testing of core baffle former bolts of the core tanks of pressurised water reactors

    International Nuclear Information System (INIS)

    Bies, Christian M.; Alaerts, Louis; Bonitz, Frank W.; Devlin, Russell S.; Minogue, Patrick

    2013-01-01

    This article presents the MIDAS VI testing robot used by Westinghouse / WesDyne. This is a remotely operated underwater vehicle which positions ultrasonic probes under camera control. This vehicle makes it possible to substantially reduce the time required for setting up and preparing ultrasonic tests on core baffle former bolts. It has also accelerated the test procedure itself. Test methods have also been developed for bolt types which were hitherto considered incapable of being tested. One of these methods is based on a phased array probe. The article also reports on experiences gained over the course of years in testing core baffle former bolts in European nuclear power plants using the SUPREEM testing robot.

  10. Design and simulations of a short optical baffle for the Lightweight Asymmetry and Magnetism Probe (LAMP)

    Science.gov (United States)

    Xing, Yujie; Wang, Zhanshan; Li, Wenbi; Yu, Jun; Feng, Hua

    2017-08-01

    The Lightweight Asymmetry and Magnetism Probe (LAMP) is a micro-satellite based mission concept for soft X-ray polarimetry at 250 eV with a large aperture but a short focal length. Due to the very low energy response of the gas pixel detector (GPD) used in LAMP, the stray light must be extremely attenuated. However, a long baffle is not favored for the micro-satellite with a limited geometry. In this paper, we propose a novel design having a short optical baffle but with high efficiency suppressing stray lights. For the optical aperture with a diameter of 700 mm used in LAMP, a short baffle of just 150 mm long can reduce the solar stray light by a factor better than 10-4 at the incidence angle larger than 60°, which is verified by simulations with TracePro ray-tracing software. This design meets the requirement for LAMP and the design concept should be helpful for other optical/UV/X-ray telescopes.

  11. Dynamic thermal baffle on lower head of FBR sodium-sodium intermediate heat exchanger

    International Nuclear Information System (INIS)

    Charbonnel, A.; Foussat, C.

    1981-01-01

    The cover head of the heat exchanger is bathed on the one side by the primary sodium of the 'cold' header of the vessel and on the other side by the secondary sodium which feeds the heat exchange tube bank through the lower tubesheet. In the case of transient or permanent operating conditions at partial ratings, there are large temperature differences between the inner sodium (inlet temperature conditions of secondary sodium) and the outer sodium (mean temperature conditions in the primary sodium outlet port), hence the necessity of designing a thermal baffle which protects the head and its connection to the tubesheet. A 'static' thermal baffle consisting of a thick steel plate enclosing static sodium around the head proves inadequate during transient operating conditions. This is why a 'dynamic' thermal baffle is used whose design is based on the fact that the primary sodium in the lower part of the outlet port is always at a temperature close to that of the secondary sodium in the inlet header and the head. The primary sodium is taken from the bottom of the outlet port by a ring deflector and circulates in an annulus created by a double housing and the head. It flows out through openings in the lower part of the housing. (orig./GL)

  12. Heat transfer in tube bundles of heat exchangers with flow baffles induced forced mixing

    International Nuclear Information System (INIS)

    AbuRomia, M.M.; Chu, A.W.; Cho, S.M.

    1976-01-01

    Thermal analysis of shell-and-tube heat exchangers is being investigated through geometric modeling of the unit configuration in addition to considering the heat transfer processes taking place within the tube bundle. The governing equations that characterize the heat transfer from the shell side fluid to the tube side fluid across the heat transfer tubewalls are indicated. The equations account for the heat transfer due to molecular conduction, turbulent thermal diffusion, and forced fluid mixing among various shell side fluid channels. The analysis, though general in principle, is being applied to the Clinch River Breeder Reactor Plant-Intermediate Heat Exchanger, which utilizes flow baffles appropriately designed for induced forced fluid mixing in the tube bundle. The results of the analysis are presented in terms of the fluid and tube wall temperature distributions of a non-baffled and baffled tube bundle geometry. The former case yields axial flow in the main bundle region while the latter is associated with axial/cross flow in the bundle. The radial components of the axial/cross flow yield the necessary fluid mixing that results in reducing the thermal unbalance among the heat transfer to the allowable limits. The effect of flow maldistribution, present on the tube or shell sides of the heat exchangers, in altering the temperature field of tube bundles is also noted

  13. Computational Investigation on Fully Developed Periodic Laminar Flow Structure in Baffled Circular Tube with Various BR

    Directory of Open Access Journals (Sweden)

    Withada Jedsadaratanachai

    2014-01-01

    Full Text Available This paper presents a 3D numerical analysis of fully developed periodic laminar flow in a circular tube fitted with 45° inclined baffles with inline arrangement. The computations are based on a finite volume method, and the SIMPLE algorithm has been implemented. The characteristics of fluid flow are presented for Reynolds number, Re = 100–1000, based on the hydraulic diameter (D of the tube. The angled baffles were repeatedly inserted at the middle of the test tube with inline arrangement to generate vortex flows over the tested tube. Effects of different Reynolds numbers and blockage ratios (b/D, BR with a single pitch ratio of 1 on flow structure in the tested tube were emphasized. The flows in baffled tube show periodic flow at x/D ≈ 2-3, and become a fully developed periodic flow profiles at x/D ≈ 6-7, depending on Re, BR and transverse plane positions. The computational results reveal that the higher of BR and closer position of turbulators, the faster of fully developed periodic flow profiles.

  14. Design and evaluation of hydraulic baffled-channel PAC contactor for taste and odor removal from drinking water supplies.

    Science.gov (United States)

    Kim, Young-Il; Bae, Byung-Uk

    2007-05-01

    Based on the concept of hydraulic flocculator, a baffled-channel powdered activated carbon (PAC) contactor, placed before the rapid-mixing basin, was designed and evaluated for removal of taste and odor (T&O) in drinking water. PAC adsorption kinetic tests for raw water samples were conducted for selection of design parameters related to contact time and degree of mixing. Within the tested range of velocity gradient (G) from 18 to 83s(-1), mixing had a relatively minor effect on the adsorption kinetics of the PAC. The hydrodynamic characteristics of the pilot-scale horizontally and vertically baffled-channel PAC contactor were investigated by tracer tests. It was found that the plug flow fractions of vertically baffled-channel PAC contactor (vBPC) were higher than those of the horizontally baffled-channel PAC contactor (hBPC) for the same bend width or bend height. However, the hBPC seems to be more appropriate than the vBPC in terms of construction and maintenance. The geosmin and MIB removal rate increased with the number of baffles, PAC dose and contact time increased regardless of bend width in the pilot-scale hBPC. The pair of full-scale hBPCs at Pohang water treatment plant, having a design capacity of 6.5x10(4)m(3)/d with 20min of hydraulic retention time with a safety factor of 2, was designed based on lab- and pilot-scale experimental results. Under a velocity gradient of 20s(-1), the number of baffles to be installed was calculated to be 20 with a space of about 2m between each baffle, resulting in a hydraulic head loss through the contactor of about 0.056m. The successful application of hBPC for T&O removal from drinking water supplies should provide momentum for developing more effective treatment methods.

  15. Investigation of Damping Physics and CFD Tool Validation for Simulation of Baffled Tanks at Variable Slosh Amplitude

    Science.gov (United States)

    Yang, H. Q.; West, Jeff

    2016-01-01

    Determination of slosh damping is a very challenging task as there is no analytical solution. The damping physics involves the vorticity dissipation which requires the full solution of the nonlinear Navier-Stokes equations. As a result, previous investigations were mainly carried out by extensive experiments. A systematical study is needed to understand the damping physics of baffled tanks, to identify the difference between the empirical Miles equation and experimental measurements, and to develop new semi-empirical relations to better represent the real damping physics. The approach of this study is to use Computational Fluid Dynamics (CFD) technology to shed light on the damping mechanisms of a baffled tank. First, a 1-D Navier-Stokes equation representing different length scales and time scales in the baffle damping physics is developed and analyzed. Loci-STREAM-VOF, a well validated CFD solver developed at NASA MSFC, is applied to study the vorticity field around a baffle and around the fluid-gas interface to highlight the dissipation mechanisms at different slosh amplitudes. Previous measurement data is then used to validate the CFD damping results. The study found several critical parameters controlling fluid damping from a baffle: local slosh amplitude to baffle thickness (A/t), surface liquid depth to tank radius (d/R), local slosh amplitude to baffle width (A/W); and non-dimensional slosh frequency. The simulation highlights three significant damping regimes where different mechanisms dominate. The study proves that the previously found discrepancies between Miles equation and experimental measurement are not due to the measurement scatter, but rather due to different damping mechanisms at various slosh amplitudes. The limitations on the use of Miles equation are discussed based on the flow regime.

  16. Kinetic study of treatment of wastewater contains food preservative agent by anaerobic baffled reactor : An overview

    Energy Technology Data Exchange (ETDEWEB)

    Sumantri, Indro; Purwanto,; Budiyono [Chemical Engineering Department, Faculty of Engineering, Diponegoro University Jl. Prof. H. Soedarto, SH, Kampus Baru Tembalang, Semarang (Indonesia)

    2015-12-29

    The characteristic of wastewater of food industries with preservative substances is high content of organic substances, degradable and high total suspended solid. High organic content in this waste forced the treatment is biologically and pointed out to anaerobic treatment. Anaerobic showed the better performance of degradation than aerobic for high content organic and also for toxic materials. During that day the treatment of food wastewater is aerobically which is high consume of energy required and high volume of sludge produced. The advantage of anaerobic is save high energy, less product of sludge, less requirement of nutrients of microorganism and high efficiency reduction of organic load. The high efficiency of reduction will reduce the load of further treatment, so that, the threshold limit based on the regulation would be easy to achieve. Research of treatment of wastewater of food industries would be utilized by both big scale industries and small industries using addition of preservative substances. The type reactor of anaerobic process is anaerobic baffled reactor that will give better contact between wastewater and microorganism in the sludge. The variables conducted in this research are the baffled configuration, sludge height, preservative agent contents, hydralic retention time and influence of micro nutrients. The respons of this research are the COD effluent, remaining preservative agent, pH, formation of volatile fatty acid and total suspended solid. The result of this research is kinetic model of the anaerobic baffled reactor, reaction kinetic of preservative agent degradation and technology of treatment wastewater contains preservative agent. The benefit of this research is to solve the treatment of wastewater of food industries with preservative substance in order to achieve wastewater limit regulation and also to prevent the environmental deterioration.

  17. Kinetic study of treatment of wastewater contains food preservative agent by anaerobic baffled reactor : An overview

    International Nuclear Information System (INIS)

    Sumantri, Indro; Purwanto,; Budiyono

    2015-01-01

    The characteristic of wastewater of food industries with preservative substances is high content of organic substances, degradable and high total suspended solid. High organic content in this waste forced the treatment is biologically and pointed out to anaerobic treatment. Anaerobic showed the better performance of degradation than aerobic for high content organic and also for toxic materials. During that day the treatment of food wastewater is aerobically which is high consume of energy required and high volume of sludge produced. The advantage of anaerobic is save high energy, less product of sludge, less requirement of nutrients of microorganism and high efficiency reduction of organic load. The high efficiency of reduction will reduce the load of further treatment, so that, the threshold limit based on the regulation would be easy to achieve. Research of treatment of wastewater of food industries would be utilized by both big scale industries and small industries using addition of preservative substances. The type reactor of anaerobic process is anaerobic baffled reactor that will give better contact between wastewater and microorganism in the sludge. The variables conducted in this research are the baffled configuration, sludge height, preservative agent contents, hydralic retention time and influence of micro nutrients. The respons of this research are the COD effluent, remaining preservative agent, pH, formation of volatile fatty acid and total suspended solid. The result of this research is kinetic model of the anaerobic baffled reactor, reaction kinetic of preservative agent degradation and technology of treatment wastewater contains preservative agent. The benefit of this research is to solve the treatment of wastewater of food industries with preservative substance in order to achieve wastewater limit regulation and also to prevent the environmental deterioration

  18. Post-Service Examination of PWR Baffle Bolts, Part I. Examination and Test Plan

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, Keith J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sokolov, Mikhail A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-04-30

    In support of extended service and current operations of the US nuclear reactor plants, the Oak Ridge National Laboratory (ORNL), through the Department of Energy (DOE), Light Water Reactor Sustainability (LWRS) Program, is coordinating with Ginna Nuclear Power Plant, The Westinghouse Electric Company, LLC, and ATI Consulting, the selective procurement of baffle bolts that were withdrawn from service in 2011 and currently stored on site at Ginna. The goal of this program is to perform detailed microstructural and mechanical property characterization of baffle former bolts following in-service exposures. This report outlines the selection criteria of the bolts and the techniques to be used in this study. The bolts available are the original alloy 347 steel fasteners used in holding the baffle plates to the baffle former structures within the lower portion of the pressurized water reactor vessel. Of the eleven possible bolts made available for this work, none were identified to have specific damage. The bolts, however, did show varying levels of breakaway torque required in their removal. The bolts available for this study varied in peak fluence (highest dose within the head of the bolt) between 9.9 and 27.8x1021 n/cm2 (E>1MeV). As no evidence for crack initiation was determined for the available bolts from preliminary visual examination, two bolts with the higher fluence values were selected for further post-irradiation examination. The two bolts showed different breakaway torque levels necessary in their removal. The information from these bolts will be integral to the LWRS program initiatives in evaluating end of life microstructure and properties. Furthermore, valuable data will be obtained that can be incorporated into model predictions of long-term irradiation behavior and compared to results obtained in high flux experimental reactor conditions. The two bolts selected for the ORNL study will be shipped to Westinghouse with bolts of

  19. ITER baffle module small-scale mock-ups: first wall thermo-mechanical testing results

    International Nuclear Information System (INIS)

    Severi, Y.; Giancarli, L.; Poitevin, Y.; Salavy, J.F.; Le Marois, G.; Roedig, M.; Vieider, G.

    1998-01-01

    The EU-home team is in charge of the R and D related to the ITER baffle first wall. Five small-scale mock-ups, using Be, CFC and W tiles and different armour/heat-sink material joints under development, have been fabricated and thermomechanically tested in FE200 (Le Creusot) and JUDITH (Juelich) electron beam facilities. The small-scale mock-ups have been submitted to thermo-mechanical fatigue tests (up to failure using accelerating techniques). The objective was to determine the performances of the armour material joints under high heat flux cycles. (orig.)

  20. Thermal interaction of core melt debris with the TMI-2 baffle, core-former, and lower head structures

    International Nuclear Information System (INIS)

    Cronenberg, A.W.; Tolman, E.L.

    1987-09-01

    Recent inspection of the TMI-2 core-former baffle walls (vertical), former plates (horizontal), and lower plenum has been conducted to assess potential damage to these structures. Video observations show evidence of localized melt failure of the baffle walls, whereas fiberoptics data indicate the presence of resolidified debris on the former plates. Lower plenum inspection also confirms the presence of 20 tons or more of core debris in the lower plenum. These data indicate massive core melt relocation and the potential for melt attack on vessel structural components. This report presents analyses aimed at developing an understanding of melt relocation behavior and damage progression to TMI-2 vessel components. Thermal analysis indicates melt-through of the baffle plates, but maintenance of structural integrity of the former plates and lower head. Differences in the damage of these structures is attributed largely to differences in contact time with melt debris and pressure of water. 29 refs., 17 figs., 9 tabs

  1. Shell side numerical analysis of a shell and tube heat exchanger considering the effects of baffle inclination angle on fluid flow using CFD

    Directory of Open Access Journals (Sweden)

    Raj Karuppa Thundil R.

    2012-01-01

    Full Text Available In this present study, attempts were made to investigate the impacts of various baffle inclination angles on fluid flow and the heat transfer characteristics of a shell-and-tube heat exchanger for three different baffle inclination angles namely 0°,10° and 20°. The simulation results for various shell and tube heat exchangers, one with segmental baffles perpendicular to fluid flow and two with segmental baffles inclined to the direction of fluid flow are compared for their performance. The shell side design has been investigated numerically by modeling a small shell-and-tube heat exchanger. The study is concerned with a single shell and single side pass parallel flow heat exchanger. The flow and temperature fields inside the shell are studied using non-commercial CFD software tool ANSYS CFX 12.1. For a given baffle cut of 36 %, the heat exchanger performance is investigated by varying mass flow rate and baffle inclination angle. From the CFD simulation results, the shell side outlet temperature, pressure drop, recirculation near the baffles, optimal mass flow rate and the optimum baffle inclination angle for the given heat exchanger geometry are determined.

  2. Effects of Movable-Baffle on Heat Transfer and Entropy Generation in a Cavity Saturated by CNT Suspensions: Three-Dimensional Modeling

    Directory of Open Access Journals (Sweden)

    Abdullah A.A.A. Al-Rashed

    2017-04-01

    Full Text Available Convective heat transfer and entropy generation in a 3D closed cavity, equipped with adiabatic-driven baffle and filled with CNT (carbon nanotube-water nanofluid, are numerically investigated for a range of Rayleigh numbers from 103 to 105. This research is conducted for three configurations; fixed baffle (V = 0, rotating baffle clockwise (V+ and rotating baffle counterclockwise (V− and a range of CNT concentrations from 0 to 15%. Governing equations are formulated using potential vector vorticity formulation in its three-dimensional form, then solved by the finite volume method. The effects of motion direction of the inserted driven baffle and CNT concentration on heat transfer and entropy generation are studied. It was observed that for low Rayleigh numbers, the motion of the driven baffle enhances heat transfer regardless of its direction and the CNT concentration effect is negligible. However, with an increasing Rayleigh number, adding driven baffle increases the heat transfer only when it moves in the direction of the decreasing temperature gradient; elsewhere, convective heat transfer cannot be enhanced due to flow blockage at the corners of the baffle.

  3. Inspection and replacement of baffle assembly screws inside American reactor vessels

    International Nuclear Information System (INIS)

    Neal, K.; Chaumont, J.C.

    1999-01-01

    The baffle assembly inside the vessel of a 900 MWe reactor designed by Framatome, is made up of 44 plates fixed on 8 horizontal supports by a system of about 1000 screws. These plates undergo high neutron flux and the problem of screw cracking appeared at the end of the eighties in the first-generation reactors. The first operation on a large scale concerning the screws of a Westinghouse type reactor, was performed on the Tihange-1 power plant where Framatome controlled 960 screws and replaced 91. In 1997 as a consequence of the Belgian and French feedback experience, American plant operators launched a vast program of preventive actions: material analysis, inspection of baffle plate screws and replacement of defective screws. This program was held in cooperation with EPRI (electric power research institute) and under the control of NRC (nuclear regulatory commission). Framatome Technologies Inc (FTI) was in charge of the in-situ inspection and replacement of the screws. FTI designed special tools and equipment adapted to the 2-loop American reactors but the basis ideas were those applied on the Tihange reactor. The successful experience of FTI has allowed the firm to be commissioned for 6 2-loops American reactors. (A.C.)

  4. A Strategy of Suppressing the Underground Impact Scattered Current in Power Grid by Using Insulation Baffle

    Science.gov (United States)

    Zhan, Qinghua; Chen, Zhucheng; Li, Hongtao; Liu, Yijun; Mei, Cheng; He, Zhijie

    2017-05-01

    In order to solve the accidents happened in the ponds or other special places around the tower which were caused by the diffusion current after lightning stroke the transmission tower, the protection measures for the problem tower in the area of Guangdong Province which occurred dead fish in the pond in thunderstorm weather were studied in this paper. The COMSOL mutiphysics simulation software was used in order to calculate the electromagnetic environment of the diffusion situation by grounding device after lightning stroke the power transmission tower. Study concluded that the safe distance between the fish pond and grounding device of transmission tower is 14 meter. The effects of the length and depth or stayed a gap of the insulation baffle on the fish in the fish pond were discussed. The protection method of the insulation baffle has important practical significance to the protection of the grounding device for diffusion current, and can provide some engineering guidance and basis for the grounding arrangement and transformation of the high voltage transmission line tower.

  5. Pilot scale application of anaerobic baffled reactor for biologically enhanced primary treatment of raw municipal wastewater.

    Science.gov (United States)

    Hahn, Martha J; Figueroa, Linda A

    2015-12-15

    A four-cell anaerobic baffled reactor (ABR) was operated for two years treating raw municipal wastewater at ambient water and air temperatures of 12-23 °C and -10 to 35 °C, respectively. The 1000-L pilot reactor operated at a 12-h hydraulic residence time and was located in the Headworks building of the Plum Creek Water Reclamation Authority. The average influent was TSS = 510 ± 400 mg/L, BOD5 = 320 ± 80 mg/L and the average removal of TSS and BOD5 was 83 ± 10% and 47 ± 15%, respectively. The TSS and BOD removal exceeded that of conventional primary clarification, with no wasting of the settled solids over the two-years and stoichiometric production of methane. The estimated energy content of the biogas produced per unit volume of wastewater treated averaged 0.45 kWh/m(3). The TSS and total COD removal in the first cell averaged 75 ± 15% and 43 ± 14%, respectively, but methane production was only 20% of the total observed for the full ABR. The performance of the ABR relative to the extent of solids hydrolysis and methane production can be varied by the number of cells and hydraulic residence time. The anaerobic baffled reactor is an energy-positive technology that can be used for biologically enhanced primary treatment of raw municipal wastewater in cold climates. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Evaluation of the Neutron Fluence at a Baffle-Former Zone in an Operating Reactor

    International Nuclear Information System (INIS)

    Lee, S. L.; Yoo, C. S.; Hwang, S. S.

    2008-01-01

    Neutron fluence evaluation has been performed on a reactor vessel in an operating nuclear power plant in order to evaluate the radiation embrittlement which is directly related to plant safety as well as a plant operating license, based on the operating history. Because, as the operating years increase, damage may occur in the internal structures such as a baffle former bolt due to various reasons, and one of these reasons comes from the neutron fluence, so called an irradiation assisted stress corrosion cracking, thus resulting in the shutdown of a plant and the replacement of a structure which has an economic disadvantage as well as a severe effect in the integrity of a plant. Neutron flux and fluence calculations for the baffle area for one of the reactors operating in Korea have been performed for all the operating cycles from the start of the reactor using real plant operating conditions such as the operating temperature, pressure and fuel loading pattern in order to evaluate any possibility that may cause a stress corrosion cracking due to the excessive neutron irradiation

  7. Decolorization and mineralization of Amaranth dye using multiple zoned aerobic and anaerobic baffled constructed wetland.

    Science.gov (United States)

    Lehl, Harvinder Kaur; Ong, Soon-An; Ho, Li-Ngee; Wong, Yee-Shian; Saad, Farah Naemah Mohd; Oon, Yoong-Ling; Oon, Yoong-Sin; Thung, Wei-Eng; Yong, Chin-Yii

    2017-08-03

    The objective of this study is to determine the reduction efficiency of Chemical Oxygen Demand (COD) as well as the removal of color and Amaranth dye metabolites by the Aerobic-anaerobic Baffled Constructed Wetland Reactor (ABCW). The ABCW reactor was planted with common reed (Phragmite australis) where the hydraulic retention time (HRT) was set to 1 day and was fed with synthetic wastewater with the addition of Amaranth dye. Supplementary aeration was supplied in designated compartments of the ABCW reactor to control the aerobic and anaerobic zones. After Amaranth dye addition the COD reduction efficiency dropped from 98 to 91% while the color removal efficiency was 100%. Degradation of azo bond in Amaranth dye is shown by the UV-Vis spectrum analysis which demonstrates partial degradation of Amaranth dye metabolites. The performance of the baffled unit is due to the longer pathway as there is the up-flow and down-flow condition sequentially, thus allowing more contact of the wastewater with the rhizomes and micro-aerobic zones.

  8. Hydrodynamic characteristics of a four-compartment periodic anaerobic baffled reactor.

    Science.gov (United States)

    Liu, Xiao-lei; Ren, Nan-qi; Wan, Chun-li

    2007-01-01

    Periodic anaerobic baffled reactor (PABR) is a novel reactor based on the design concept of anaerobic baffled reactor (ABR). Residence time distribution (RTD) studies on both clean and working reactors at the same hydraulic residence time (HRT) of 2 d were carried out to investigate the dead spaces and mixing patterns in PABRs at different organic loading rates (OLRs) in various switching manners and frequencies. The results showed that the fraction of dead space in PABR was similar to that in ABR, which was low in comparison with other reactor designs. Dead space may be divided into two categories, hydraulic and biological. In RTD studies without biomass, the hydraulic dead space in the PABR run in an "every second" switching manner with T = 2 d was the lowest whereas that in the PABR run in a T = infinity (ABR) switching manner was the highest. The same trend was obtained with the total dead space in RTD studies with biomass no matter what the OLR was. Biological dead space was the major contributor to dead space but affected decreasingly at higher OLR whichever switching manner the PABR run in. The flow patterns within the PABRs were intermediate between plug-flow and perfectly mixed under all the conditions tested.

  9. Metallurgical examinations update of baffle bolts removed from operating French PWR. Microstructural investigations of a baffle to former bolt located on a high level of the internal structures

    International Nuclear Information System (INIS)

    Panait, C.; Fargeas, E.; Miloudi, S.; Moulart, P.; Tommy-Martin, M.; Monteil, N.; Pokor, C.

    2015-01-01

    This paper presents the microstructural investigations conducted on a cracked baffle to former bolt extracted from an upper former level of the internal structures of a French Pressurized Water Reactor (PWR). Extensive microstructural investigations using Light Microscopy, Scanning Electron Microscopy and Transmission Electron Microscopy (TEM) have been conducted to understand the degradation mechanisms of this bolt. TEM investigations have revealed neutron irradiation damage in the microstructure of the bolt such as Frank loops and cavities and/or bubbles. The number of features per unit volume as a function of diameter was determined in the head and in the shank of the bolt. The obtained results are relatively similar to those obtained for other damaged bolts extracted from PWR-type reactors and irradiated in similar conditions (dose and temperature). The irradiation damage has induced an evolution of the mechanical properties (hardening of the material), as revealed by the hardness measurements along the bolt, with a higher average value in the head (400 HV), compared to the shank (15 mm under the head), about 340 HV. The metallurgical investigations have confirmed that this bolt was damaged by Irradiation Assisted Stress Corrosion Cracking (IASCC)

  10. Experimental investigation of effect of flow attack angle on thermohydraulic performance of air flow in a rectangular channel with discrete V-pattern baffle on the heated plate

    Directory of Open Access Journals (Sweden)

    Raj Kumar

    2016-05-01

    Full Text Available In this work, the effect of angle of attack ( α a of the discrete V-pattern baffle on thermohydraulic performance of rectangular channel has been studied experimentally. The baffle wall was constantly heated and the other three walls of the channel were kept insulated. The experimentations were conducted to collect the data on Nusselt number ( N u b and friction factor ( f b by varying the Reynolds number (Re = 3000–21,000 and angle of attack ( α a from 30° to 70°, for the kept values of relative baffle height ( H b / H = 0 . 50 , relative pitch ratio ( P b / H = 1 . 0 , relative discrete width ( g w / H b = 1 . 5 and relative discrete distance ( D d / L v = 0 . 67 . As compared to the smooth wall, the V-pattern baffle roughened channel enhances the Nusselt number ( N u b and friction factor ( f b by 4.2 and 5.9 times, respectively. The present discrete V-pattern baffle shapes with angle of attack ( α a of 60° equivalent to flow Reynolds number of 3000 yields the greatest thermohydraulic performance. Discrete V-pattern baffle has improved thermal performance as compared to other baffle shapes’ rectangular channel.

  11. Active control of radiated sound power from a baffled, rectangular panel

    DEFF Research Database (Denmark)

    Mørkholt, Jakob

    1996-01-01

    with an array of eleven microphones in front of the panel, is very close to minimising the actual radiated sound power. Practical experiments where such an array estimate has been minimised using the filtered X LMS algorithm have shown that substantial reductions of radiated sound power can be obtained over......Active control of radiated sound power from a rectangular baffled panel by minimisation of an accurate power estimate, using piezoceramic actuators, has been investigated. Computer simulations have shown that minimising a power estimate obtained by discretised integration of the far field intensity...... a broad frequency range using few piezoceramic actuators, provided that an accurate estimate of the sound power is available for minimisation....

  12. Experimental validation of the sound transmission of rectangular baffled plates with general elastic boundary conditions.

    Science.gov (United States)

    Ou, Dayi; Mak, Cheuk Ming

    2011-06-01

    Several prediction methods have recently been developed for systematically studying the effects of general boundary conditions on the sound transmission loss (STL) of plate-like structures. But corresponding experimental validation studies remain scarce owing to the difficulty of obtaining accurate boundary conditions for practical structures. This paper presents a convincing experiment conducted on a baffled plate system to validate the STL prediction model in a previous paper by Yu et al. [Noise Control Eng. J. 58(2), 187-200, 2010]. A method is proposed to determine the boundary conditions of this system, and experimental STL compares well with the predictions based on the identified boundary condition. © 2011 Acoustical Society of America

  13. Arc erosion of full metal plasma facing components at the inner baffle region of ASDEX Upgrade

    Directory of Open Access Journals (Sweden)

    V. Rohde

    2016-12-01

    Full Text Available At the inner baffle of the AUG divertor massive polished inserts of tungsten and P92 steel were installed to measure the erosion by arcing. For tungsten most of the traces are less than 0.4µm deep and a similar amount of tungsten is deposited close to the traces. Few craters up to 4µm resulting in an average erosion rate of 2×1013 at cm−2s−1 are observed. The behaviour for P92 steel is quite different: most of the traces are 4µm deep, up to 80µm were observed. An average erosion rate of 400×1013 at cm−2s−1, i.e. more than a factor of hundred higher compared to tungsten, is found. Therefore, erosion by arcing has to be taken into account to determine the optimal material mix for future fusion devices.

  14. A modified generalized equivalence theory for homogenization of the assembly and baffle/reflector

    International Nuclear Information System (INIS)

    Cheng, Hongwu; Cho, Nam-Zin

    1996-01-01

    Based on detailed investigations into the generalized equivalence theory (GET), a more generalized equivalence theory (MGET) has been put forward. In this theory, usual nodal surface flux discontinuity factors are replaced by nodal outgoing or incoming partial current discontinuity factors, which leads to a new interface condition in nodal diffusion methods, while nodal equivalent cross sections still take on the flux-volume-weighted constants (FVWs). It is shown from the numerical experiments that for the heterogeneous problems with the explicit baffle, the equivalent parameters defined by MGET are nearly of the same order as those defined by GET. However, if the core burnup state is considered, it turns out that the outgoing partial current discontinuity factors are much more insensitive to the core state than the flux discontinuity factors and the incoming partial current discontinuity factors. (author)

  15. Feasibility of an Anaerobic Baffled Reactor (ABR In Treating Starch Industry Wastewater

    Directory of Open Access Journals (Sweden)

    Ali Assadi

    2007-03-01

    Full Text Available The anaerobic baffled reactor (ABR includes a mixed anaerobic culture separated into compartments and a novel process with a series of vertical baffles at each compartment. It dose not require granulation for its operation, resulting in shorter start-up time. In this study, the feasibility of the ABR process was investigated for the treatment of wheat flour starch wastewater. Simple gravity settling was used to remove suspended solids from the starch wastewater and used as feed. Start-up of a reactor (13.5L with five compartments using a diluted feed of approximately 4500 mg/L chemical oxygen demand (COD was accomplished in about 9 weeks using seed sludge from the anaerobic digester of a municipal wastewater treatment plant. The reactor with a hydraulic retention time (HRT of 72 h at 35°C and an initial organic loading rate (OLR of 1.2 kgCOD/m3.d showed a removal efficiency of 61% COD. The best reactor performance was observed with an organic loading rate of 2.5 kgCOD/m3.d (or hydraulic retention time of 2.45 d when a COD conversion of 67% was achieved. The main advantage of using an ABR comes from its compartmentalized structure. The first compartment of an ABR may act as a buffer zone to all toxic and inhibitory materials in the feed and, thus, allows the later compartments to be loaded with a relatively harmless, more uniform, and mostly acidified influent. In this respect, the later compartments would be more likely to support active populations of the relatively sensitive methanogenic bacteria.

  16. Radiative and SOL experiments in open and baffled divertors on DIII-D

    International Nuclear Information System (INIS)

    Allen, S.L.; Brooks, N.H.; Bastasz, R.

    1998-11-01

    The authors present recent progress towards an understanding of the physical processes in the divertor and scrape-off-layer (SOL) plasmas in DIII-D. This has been made possible by a combination of new diagnostics, improved computational models, and changes in divertor geometry. They have focused primarily on ELMing H-mode discharges. The physics of Partially Detached Divertor (PDD) plasmas, with divertor heat flux reduction by divertor radiation enhancement using D 2 puffing, has been studied in 2-D, and a model of the heat and particle transport has been developed that includes conduction, convection, ionization, recombination, and flows. Plasma and impurity particle flows have been measured with Mach probes and spectroscopy and these flows have been compared with the UEDGE model. The model now includes self-consistent calculations of carbon impurities. Impurity radiation has been increased in the divertor and SOL with puff and pump techniques using SOL D 2 puffing, divertor cryopumping, and argon puffing. The important physical processes in plasma-wall interactions have been examined with a DiMES probe, plasma characterization near the divertor plate, and the REDEP code. Experiments comparing single-null (SN) plasma operation in baffled and open divertors have demonstrated a change in the edge plasma profiles. These results are consistent with a reduction in the core ionization source calculated with UEDGE. Divertor particle control in ELMing H-mode with pumping and baffling has resulted in reduction in H-mode core densities to n e /n gw ∼ 0.25. Divertor particle exhaust and heat flux has been studied as the plasma shape was varied from a lower SN, to a balanced double null (DN), and finally to an upper SN

  17. Sound transmission through a finite perforated panel set in a rigid baffle: A fully coupled analysis

    Science.gov (United States)

    Akkoorath Mana, Anoop; Sonti, Venkata R.

    2018-02-01

    Sound transmission through a fluid-loaded finite perforated panel set in an infinite unperforated rigid baffle is considered. Using a fully coupled formulation in the 2-D wavenumber domain, the transmitted pressure due to an incident plane wave is obtained. The change in the panel resonances caused by the perforations is accounted for. The formulation also takes into account the self- and inter-modal coupling coefficients arising due to the fluid-loading effect. The derivation is almost entirely analytical with numerical computations done at the very end. Transmission loss (TL) curves are plotted for various cases and the physics is discussed. Along the way an uncoupled calculation is also done for the sake of comparison. The results are mainly for a light medium like air. For a light medium, in general, the perforate impedance is lower than the panel impedance. Thus, most of the transmission happens through the perforations. The panel velocity contribution is insignificant and hence the uncoupled calculation is adequate. In general, the absolute perforate impedance increases with increasing frequency. So does the TL. At low frequencies, because the resistive component of the hole impedance increases, the absolute perforate impedance rises. Thus, the TL curves rise at the lower frequencies. This effect is prominent for sub-millimeter hole radii, i.e., for micro-perforations. An important issue with the TL values for perforated panels is that they sometimes acquire negative values at low frequencies. This apparent anomaly is resolved by showing that at low frequencies there is an additional power component that flows from the baffle region onto the panel. Upon inclusion of this additional term, the TL values remain positive at all frequencies.

  18. FEM-DBEM approach to analyse crack scenarios in a baffle cooling pipe undergoing heat flux from the plasma

    Directory of Open Access Journals (Sweden)

    R. Citarella

    2017-02-01

    Full Text Available Wendelstein 7-X is the world’s largest nuclear fusion experiment of stellarator type, in which a hydrogen plasma is confined by a magnet field generated with external superconducting coils, allowing the plasma to be heated up to the fusion temperature. The water-cooled Plasma Facing Components (PFC protect the Plasma Vessel (PV against radiative and convective heat from the plasma. After the assembly process of heat shields and baffles, several cracks were found in the braze and cooling pipes. Due to heat load cycles occurring during each Operational Phase (OP, thermal stresses are generated in the heat sinks, braze root and cooling pipes, capable to drive fatigue crack-growth and, possibly, a water leak through the pipe thickness. The aim of this study is to assess the most dangerous initial crack configurations in one of the most critical baffles by using numerical models based on a FEM-DBEM approach.

  19. Validation of Slosh Model Parameters and Anti-Slosh Baffle Designs of Propellant Tanks by Using Lateral Slosh Testing

    Science.gov (United States)

    Perez, Jose G.; Parks, Russel, A.; Lazor, Daniel R.

    2012-01-01

    The slosh dynamics of propellant tanks can be represented by an equivalent mass-pendulum-dashpot mechanical model. The parameters of this equivalent model, identified as slosh mechanical model parameters, are slosh frequency, slosh mass, and pendulum hinge point location. They can be obtained by both analysis and testing for discrete fill levels. Anti-slosh baffles are usually needed in propellant tanks to control the movement of the fluid inside the tank. Lateral slosh testing, involving both random excitation testing and free-decay testing, are performed to validate the slosh mechanical model parameters and the damping added to the fluid by the anti-slosh baffles. Traditional modal analysis procedures were used to extract the parameters from the experimental data. Test setup of sub-scale tanks will be described. A comparison between experimental results and analysis will be presented.

  20. Slosh Baffle Design and Test for Spherical Liquid Oxygen and Liquid Methane Propellant Tank for a Lander

    Science.gov (United States)

    Strahan, Alan; Hernandez, Humberto

    2011-01-01

    A Vertical Test Bed (VTB) is being developed to investigate exploration technologies with earth-based landing trajectories. During this activity, a concern emerged that the VTB, with large liquid tanks, could experience unstable slosh interaction between the propellant fluid motion and the control system, leading to an investigation of slosh characteristics of the VTB. As such, slosh modeling, analysis and testing were performed, that both verified models and lead to the conclusion that baffles would be required for the full-scale vehicle. Follow-on design and testing supported development of these baffles and measurement of their performance. The majority of the tests conducted, including both subscale and full, involved the use of clear tanks containing water as a reasonable substitute for the cryogenic propellants, though a few tests involved the actual liquid oxygen and methane. Along the way, some unique test and data recording methods were employed to reduce testing complexity and cost.

  1. Experimental investigation on a semi-circular trough-absorber solar still with baffles for fresh water production

    International Nuclear Information System (INIS)

    Sathyamurthy, Ravishankar; Nagarajan, P.K.; El-Agouz, S.A.; Jaiganesh, V.; Sathish Khanna, P.

    2015-01-01

    Highlights: • Experiments are carried out to analyze the performance. • Baffles are placed in the absorber to increase the residence time of water with solar intensity. • Yield of fresh water from present solar still is 16.66% more than a conventional solar still. • Payback period of the present model is quicker. - Abstract: The main objective of this research is to increase the contact time of water in the basin to enhance yield of fresh water by using a semicircular absorber solar still with baffles. An experimental as well as theoretical investigation is carried out. The productivity and efficiency of present still are analyzed with the influence of the number baffles and the water flow rate. A good agreement between the experimental and theoretical results is observed. The results indicate that, the daily yield of present solar still is higher than that for conventional still approximately by 16.66%. The outlet water temperature present solar still is high subsequently, it can be coupled with multi-state of solar stills to increase productivity. Therefore, the present solar still can be sufficiently extended for other continuous solar desalination systems. Economic analysis concluded that, the payback period of the present model solar still is quicker while comparing it with other solar still

  2. Prediction of void swelling in the baffle ring of WWER-1000 reactors for service life of 30-60 years

    Science.gov (United States)

    Kalchenko, A. S.; Bryk, V. V.; Lazarev, N. P.; Voyevodin, V. N.; Garner, F. A.

    2013-06-01

    Major internal components of WWER-type nuclear reactors are made from annealed 18Cr10NiTi steel, a close analog to AISI 321. Void swelling of the baffle ring in particular could be a major factor limiting operation of the reactor beyond the current 30 years license. A predictive swelling equation is needed to forecast the spatial variation of swelling so as to identify those areas requiring additional attention. Available data on the swelling of this steel arising from irradiation in the BOR-60 fast reactor was combined with data from a heavy ion accelerator at higher displacement rates to formulate a predictive equation of swelling for the WWER-relevant range of temperature, irradiation dose and dose rates. This equation was used to estimate the swelling distribution over a cross-section of the baffle ring of a WWER reactor during a service life up to 60 years, reaching a local maximum of ˜30% swelling. It was shown that void swelling extends over a larger portion of the baffle ring than previously expected and exhibits a very complex and irregular distribution in response to complex distributions of temperature and dpa rate. Most importantly, as operation is extended beyond 30 years several areas of the ring may experience swelling in excess of 10% where void-induced embrittlement begins and one area may exceed 20% after 45 years, a swelling level where a complete loss of ductility is known to occur.

  3. Investigations of the Gas-Liquid Multiphase System Involving Macro-Instability in a Baffled Stirred Tank Reactor

    Directory of Open Access Journals (Sweden)

    Shuo Zhang

    2016-01-01

    Full Text Available Bubble Sauter Mean Diameter (SMD in gas-liquid multiphase system is of particular interest and the quantification of gas characteristics is still a challenge today. In this contribution, multiphase Computational Fluid Dynamic (CFD simulations are combined with Population Balance Model (PBM to investigate the bubble SMD in baffled stirred tank reactor (STR. Hereby, special attention is given to the phenomenon known as the fluid macro-instability (MI, which is a large-scale low-frequency fluid velocity variation in baffled STRs, since the fluid MIs have a dominating influence on the bubble breakage and coalescence processes. The simulations, regarding the fluid velocity, are validated with Laser Doppler Anemometry (LDA experiments, in which the instant radial velocity is analyzed through Fast Fourier Transform (FFT spectrum. The frequency peaks of the fluid MIs are found both in the simulation and in the experiment with a high degree of accuracy. After the validation, quantitative predictions of overall bubble SMD with and without MIs are carried out. Due to the accurate prediction of the fluid field, the influence of the fluid MI to bubble SMD is presented. This result provides more adequate information for engineers working in the field of estimating bubble SMDs in baffled STRs.

  4. Optimum radii and heights of U-shaped baffles in a square duct heat exchanger using surrogate-assisted optimization

    Directory of Open Access Journals (Sweden)

    Kittinan Wansasueb

    2017-06-01

    Full Text Available In this paper, optimum U-shaped baffles in a square channel heat exchanger using air as a working fluid were developed using surrogate-assisted optimization. The design problem is set to maximize heat transfer performance and simultaneously minimize pressure loss across the channel. Design variables determine the radii and heights of the baffles, whereas the optimization problem is treated as box-constrained optimization. The work in this paper is aimed at finding an appropriate surrogate model for designing such a heat exchanger system. Function evaluations are performed by means of computational fluid dynamics (CFD. The computations are based on the finite volume method and are carried out at a Reynolds number of 4000. It has been found that the use of U-shaped baffles as heat transfer enhancement devices improves the thermal performance of the heat exchanger. Comparative results reveal that the Kriging model is the most accurate surrogate model, however, the surrogate model giving the best result is support vector regression.

  5. Anaerobic baffled reactor coupled with chemical precipitation for treatment and toxicity reduction of industrial wastewater.

    Science.gov (United States)

    Laohaprapanona, Sawanya; Marquesa, Marcia; Hogland, William

    2014-01-01

    This study describes the reduction of soluble chemical oxygen demand (CODs) and the removal of dissolved organic carbon (DOC), formaldehyde (FA) and nitrogen from highly polluted wastewater generated during cleaning procedures in wood floor manufacturing using a laboratory-scale biological anaerobic baffled reactor followed by chemical precipitation using MgCI2 .6H20 + Na2HPO4. By increasing the hydraulic retention time from 2.5 to 3.7 and 5 days, the reduction rates of FA, DOC and CODs of nearly 100%, 90% and 83%, respectively, were achieved. When the Mg:N:P molar ratio in the chemical treatment was changed from 1:1:1 to 1.3:1:1.3 at pH 8, the NH4+ removal rate increased from 80% to 98%. Biologically and chemically treated wastewater had no toxic effects on Vibrio fischeri and Artemia salina whereas chemically treated wastewater inhibited germination of Lactuca sativa owing to a high salt content. Regardless of the high conductivity of the treated wastewater, combined biological and chemical treatment was found to be effective for the removal of the organic load and nitrogen, and to be simple to operate and to maintain. A combined process such as that investigated could be useful for on-site treatment of low volumes of highly polluted wastewater generated by the wood floor and wood furniture industries, for which there is no suitable on-site treatment option available today.

  6. Removal of Organic Load in Communal Wastewater by using the Six Stage Anaerobic Baffle Reactor (ABR

    Directory of Open Access Journals (Sweden)

    Trilita Minarni Nur

    2016-01-01

    Full Text Available The reduction of water quality in the urban drainage is a crucial problem to overcome because it can affect the health of community. This fact encouraged the researcher to conduct the research in efforts to increase the water quality in the drainage. One of the solutions to increase the water quality in the drainage is that the domestic wastewater must be treated at first before it is flown through the drainage. Furthermore, the wastewater treatment was conducted by employing the communal wastewater processor. The research was aimed at knowing the capability of Anaerobic Baffle Reactor with the six-stage design in communal wastewater processor in efforts to decrease the organic load. This research was conducted in a laboratory scale. Meanwhile, the sort of waste used was taken from the domestic wastewater of settlement by varying its discharge and waste concentration flowing into the waste processor. Finally, the research result showed that the reduction of organic load of COD was reaching up to 92%, N was 85% and Phosphate was 50%.

  7. Application of beryllium as first wall armour for ITER primary, baffle and limiter modules

    International Nuclear Information System (INIS)

    Cardella, A.; Barabash, V.; Ioki, K.; Yamada, M.; Mazul, I.; Merola, M.; Strebkov, Y.

    2000-01-01

    During the engineering design activities of the ITER project, beryllium has been selected as the armour material for the first wall of the primary, baffle and limiter blanket modules. These components have different requirements according to their function, so the armour design and its joining technology has been developed in order to withstand different operating and loading conditions. Extensive R and D has been performed to develop, select and characterise the beryllium material and the joining techniques. In parallel, beryllium plasma spray coating has been developed, mainly as a possible in situ repair method for locally damaged areas. For the reduced technical objectives / reduced cost (RTO/RC) ITER project, it is proposed to maintain Be as the reference armour material and to optimise the manufacturing technologies in order to minimise costs. The paper presents the rationale of the design choices for the application of beryllium to the blanket first wall and gives an overview of the R and D performed and the results achieved. (orig.)

  8. Biologic treatment of wastewater from cassava flour production using vertical anaerobic baffled reactor (VABR

    Directory of Open Access Journals (Sweden)

    Gleyce T Correia

    2008-08-01

    Full Text Available The estimate cassava production in Brazil in 2007 was of 25 million tons (= 15% of the world production and most of it is used in the production of flour. During its processing, waste that can cause environmental inequality is generated, if discharged inappropriately. One of the liquid waste generated, manipueira, is characterized by its high level of organic matter. The anaerobic treatment that uses a vertical anaerobic baffled reactor (VABR inoculated with granulated sludge, is one of the ways of treating this effluent. The anaerobic biodigestion phases are separated in this kind of reactor, allowing greater stability and resistance to load shocks. The VABR was built with a width/height rate of 1:2. The pH, acidity, alkalinity, turbidity and COD removal were analyzed in 6 different regions of the reactor, which was operated with an increasing feeding from ? 2000 to ? 10000 mg COD L?¹ and HRT between 6.0 and 2.5 days. The VABR showed decreasing acidity and turbidity, an increase in alkalinity and pH, and 96% efficiency in COD removal with 3-day HRT and feeding of 3800 mg COD L?¹.

  9. Achieving advanced nitrogen removal for small flow wastewater using a baffled bioreactor (BBR) with intermittent aeration.

    Science.gov (United States)

    Liu, Guoqiang; Wang, Jianmin

    2017-09-01

    Nitrogen discharge from decentralized and onsite wastewater treatment systems, such as recirculating sand filters, stabilization ponds, and septic tanks, is an important source of groundwater and surface water contamination. This study demonstrated a simple baffled bioreactor (BBR) technology, operated with an intermittent aeration mode, that effectively removed nearly all nitrogen for small flow wastewater treatment. The BBR is characterized by an aeration zone, followed by an integrated internal settler, which automatically retains a high biomass concentration of approximately 6 g/L without using a separate sludge return device. Long-term testing results indicated that this process had reduced the chemical oxygen demand and total nitrogen concentration to approximately 20 mg/L and less than 3 mg-N/L, respectively, under an operational temperature of 7.1 °C to 24.7 °C. The average effluent ammonia and nitrate concentrations were 0.75 and 0.61 mg-N/L, respectively, indicating that both nitrification and denitrification had been completed. In addition to nitrogen removal, this BBR had removed approximately 65% of the total phosphorus. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. A horizontal plug-flow baffled bioelectrocatalyzed reactor for the reductive decolorization of Alizarin Yellow R.

    Science.gov (United States)

    Sun, Qian; Li, Zhiling; Wang, Youzhao; Cui, Dan; Liang, Bin; Thangavel, Sangeetha; Chung, Jong Shik; Wang, Aijie

    2015-11-01

    An application-oriented membrane-free, continuous plug-flow baffled bioelectrocatalyzed reactor (PFB-BER), was designed and testified for the decolorization of Alizarin Yellow R. Decolorization efficiency (DE) with an external power source of 0.5 V was higher than without electrolysis, i.e. 93.4% versus 73.6% (HRT of 24 h). Product formation efficiencies of p-phenylenediamine and 5-aminosalicylic acid were above 95% and 50%, respectively. When HRT decreased to 8 h and 4 h, DE reduced to 69.9% and 44.9%, respectively. An additional electrode assembly improved DE to 96.4% (HRT of 8 h) and 80% (HRT of 4 h), while energy consumption (HRT of 4 h) was lower than that of HRT of 12 h with single electrode assembly under comparable DE. The PFB-BER with higher removal capacity, lower internal resistance and energy consumption provides a new solution to treat the high loading azo dye-containing wastewaters. Copyright © 2015. Published by Elsevier Ltd.

  11. PERFORMANCE EVALUATION OF AN ANAEROBIC BAFFLED REACTOR TREATING WHEAT FLOUR STARCH INDUSTRY WASTEWATER

    Directory of Open Access Journals (Sweden)

    H. Movahedyan, A. Assadi, A. Parvaresh

    2007-04-01

    Full Text Available Feasibility of the anaerobic baffled reactor process was investigated for the treatment of wheat flour starch wastewater. After removal of suspended solids by simple gravity settling, starch wastewater was used as a feed. Start-up of a reactor (with a volume of 13.5 L and five compartments with diluted feed of approximately 4500 mg/L chemical oxygen demand was accomplished in about 9 weeks using seed sludge from anaerobic digester of municipal wastewater treatment plant. The reactor with hydraulic retention time of 72h at 35°C and initial organic loading rate of 1.2 kgCOD/m3.d showed 61% COD removal efficiency. The best performance of reactor was observed with an organic loading rate of 2.5 kgCOD/m3.d or hydraulic retention time of 2.45 d and the COD conversion of 67% was achieved. The system also showed very high solids retention with effluent suspended solids concentration of about 50 mg/L for most organic and hydraulic loadings studied. Based on these observations, the ABR process has potential to treat food industrial wastewater as a pretreatment and is applicable for extreme environmental conditions.

  12. Enrichment of syngas-converting communities from a multi-orifice baffled bioreactor.

    Science.gov (United States)

    Arantes, Ana L; Alves, Joana I; Stams, Alfons J M; Alves, M Madalena; Sousa, Diana Z

    2017-11-21

    The substitution of natural gas by renewable biomethane is an interesting option to reduce global carbon footprint. Syngas fermentation has potential in this context, as a diverse range of low-biodegradable materials that can be used. In this study, anaerobic sludge acclimatized to syngas in a multi-orifice baffled bioreactor (MOBB) was used to start enrichments with CO. The main goals were to identify the key players in CO conversion and evaluate potential interspecies metabolic interactions conferring robustness to the process. Anaerobic sludge incubated with 0.7 × 10 5  Pa CO produced methane and acetate. When the antibiotics vancomycin and/or erythromycin were added, no methane was produced, indicating that direct methanogenesis from CO did not occur. Acetobacterium and Sporomusa were the predominant bacterial species in CO-converting enrichments, together with methanogens from the genera Methanobacterium and Methanospirillum. Subsequently, a highly enriched culture mainly composed of a Sporomusa sp. was obtained that could convert up to 1.7 × 10 5  Pa CO to hydrogen and acetate. These results attest the role of Sporomusa species in the enrichment as primary CO utilizers and show their importance for methane production as conveyers of hydrogen to methanogens present in the culture. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  13. Treatment of low strength complex wastewater using an anaerobic baffled reactor (ABR).

    Science.gov (United States)

    Gopala Krishna, G V T; Kumar, Pramod; Kumar, Pradeep

    2008-11-01

    Treatment of a low strength complex wastewater of chemical oxygen demand (COD) around 500mg/L was studied in a 10L capacity laboratory scale anaerobic baffled reactor (ABR). It was operated at hydraulic retention times (HRTs) of 20, 15, 10, 8 and 6h. Corresponding organic loading rates (OLRs) were 0.6, 0.8, 1.2, 1.5 and 2kg COD/m3d. At every HRT (or OLR), pseudo steady state (PSS) was achieved. Even at maximum OLR of 2kg COD/m3d, COD and biochemical oxygen demand (BOD) removals exceeded 88%. Removal of particulate fraction of organics was found to be greater than soluble fraction. Compartment-wise studies of various parameters revealed that if the OLR was larger, the number of initial compartments played significant role in the removal of organics. The values of volatile fatty acids (VFA) demonstrated that hydrolysis and acidogenesis were the main biochemical activities in the initial few compartments. Based on the tracer studies, dead space in the ABR was found to range from 23% to 34%. The flow pattern in the ABR was classified as intermediate between plug flow and perfectly mixed flows. Observations from scanning electron micrographs (SEM) also suggested that distinct phase separation takes place in an ABR. Study of organic and hydraulic shock loads revealed that ABR was capable of sustaining the type of shock loads generally experienced at a sewage treatment plant (STP).

  14. Hydraulic characteristics simulation of an innovative self-agitation anaerobic baffled reactor (SA-ABR).

    Science.gov (United States)

    Qi, Wei-Kang; Hojo, Toshimasa; Li, Yu-You

    2013-05-01

    An investigation was conducted on a self-agitation anaerobic baffled reactor (SA-ABR) with agitation caused solely by the release of stored gas. The compound in the reactor is mixed without the use of any mechanical equipment and electricity. The computational fluid dynamics (CFD) simulation used to provide details of the flow pattern and information about the agitation process and a solid basis for design and optimization purposes. Every self-agitation cycle could be separated into the pressure energy storage process, the exergonic process and the buffer stage. The reactor is regarded as the combination of continuous stirred tank reactor and a small plug flow reactor. The liquid level and diffusion varies widely depending on the length of the U-tube. The compound transition phenomenon in the 1st chamber mainly occurs during the energy exergonic process and buffer stage. The fluid-diffusion in the 3rd and 4th chambers mainly happens after the buffer period. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  15. Experimental study of hydrodynamic and operation start of a baffled anaerobic reactor treating sewage

    Directory of Open Access Journals (Sweden)

    Ana Carolina Silveira Perico

    2009-12-01

    Full Text Available It is important to provide individual sanitation systems for sewage peri-urban communities or rural areas to minimize impacts on the environment and human health caused by sewage discharge in natura into water resources. In this context, the anaerobic digestion of effluent has been one of the main considered technologies due to easy implementation, material minimization and reduction in waste production. The objective of this work was to study a Baffled Anaerobic Reactor (BAR including its hydrodynamic characteristics, percentile of inoculum to be applied and reactor operation start. It was concluded that the flow is dispersed with 3.84% of dead spaces and that 20% of the cow manure provided best results; however, due to the high fiber content of the manure, its use is not recommended as inoculum. The BAR system, composed of four chambers, presented good performance for sewage treatment of a rural community in terms of organic substance removal (COD, turbidity and solids meeting effluent disposal standards of these parameters considering the Federal and Minas Gerais State legislation, in Brazil, even in a transient phase of operation, at temperatures below 20°C. However, the effluents from the BAR can’t be released into water bodies without other parameters such as nitrogen, phosphorus, fecal coliforms, and others are investigated to be conforming to those standards.

  16. An efficient analytical model for baffled, multi-celled membrane-type acoustic metamaterial panels

    Science.gov (United States)

    Langfeldt, F.; Gleine, W.; von Estorff, O.

    2018-03-01

    A new analytical model for the oblique incidence sound transmission loss prediction of baffled panels with multiple subwavelength sized membrane-type acoustic metamaterial (MAM) unit cells is proposed. The model employs a novel approach via the concept of the effective surface mass density and approximates the unit cell vibrations in the form of piston-like displacements. This yields a coupled system of linear equations that can be solved efficiently using well-known solution procedures. A comparison with results from finite element model simulations for both normal and diffuse field incidence shows that the analytical model delivers accurate results as long as the edge length of the MAM unit cells is smaller than half the acoustic wavelength. The computation times for the analytical calculations are 100 times smaller than for the numerical simulations. In addition to that, the effect of flexible MAM unit cell edges compared to the fixed edges assumed in the analytical model is studied numerically. It is shown that the compliance of the edges has only a small impact on the transmission loss of the panel, except at very low frequencies in the stiffness-controlled regime. The proposed analytical model is applied to investigate the effect of variations of the membrane prestress, added mass, and mass eccentricity on the diffuse transmission loss of a MAM panel with 120 unit cells. Unlike most previous investigations of MAMs, these results provide a better understanding of the acoustic performance of MAMs under more realistic conditions. For example, it is shown that by varying these parameters deliberately in a checkerboard pattern, a new anti-resonance with large transmission loss values can be introduced. A random variation of these parameters, on the other hand, is shown to have only little influence on the diffuse transmission loss, as long as the standard deviation is not too large. For very large random variations, it is shown that the peak transmission loss

  17. Hydrogen production from diluted molasses by anaerobic hydrogen producing bacteria in an anaerobic baffled reactor (ABR)

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jianzheng; Zhu, Gefu; Ren, Nanqi; Bo, Lixin; He, Junguo [Harbin Institute of Technology, Harbin (China). School of Municipal and Environmental Engineering; Li, Baikun [University of Connecticut, Storrs, CT (United States). Department of Civil and Environmental Engineering

    2007-10-15

    Hydrogen production from diluted molasses by anaerobic fermentation bacteria was investigated in a three-compartment anaerobic baffled reactor (ABR) with an effective volume of 27.48 L. After being inoculated with aerobic activated sludge and operated at chemical oxygen demand (COD) of 5000 mg/L and temperature of 35 C for 26 days, the ABR achieved stable ethanol-type fermentation. The liquid fermentation products, including volatile fatty acids (VFAs) and ethanol, stabilized at 1254, 2053, and 2761 mg/L in the three compartments, respectively. Effluent pH, oxidation-reduction potential (ORP), and alkalinity ranged at 4.3-4.4, -241 to -249mV, and 306-334mgCaCO{sub 3}/L, respectively. The hydrogen yield of the ABR was 32.51 L/d at the stable operation status, specific hydrogen production rate of anaerobic activated sludge was 0.13 L/g MLVSS d, and the substrate conversion rate was 0.13 L/g COD. Hydrogen yields, fermentation types, and acclimatization durations varied in each compartment, with the 1st compartment having lowest hydrogen yield but longest acclimatization duration and the 2nd and 3rd compartments having higher hydrogen yields but shorter acclimatization durations. The study found that the individual compartment configuration in the ABR system provided a favorable environment for different types of anaerobic bacteria. Compared with complete stirring tank reactor (CSTR), the ABR system had a better operation stability and microbial activity, which led to higher substrate conversion rate and hydrogen production ability. (author)

  18. Sulfidogenic biotreatment of synthetic acid mine drainage and sulfide oxidation in anaerobic baffled reactor.

    Science.gov (United States)

    Bekmezci, Ozan K; Ucar, Deniz; Kaksonen, Anna H; Sahinkaya, Erkan

    2011-05-30

    The treatment of synthetic acid mine drainage (AMD) water (pH 3.0-6.5) containing sulfate (3.0-3.5 g L(-1)) and various metals (Co, Cu, Fe, Mn, Ni, and Zn) was studied in an ethanol-fed sulfate-reducing 4-compartment anaerobic baffled reactor (ABR) at 32°C. The reactor was operated for 160 days at different chemical oxygen demand (COD)/sulfate ratios, hydraulic retention times (HRT), pH, and metal concentrations to study the robustness of the process. The last compartment of the reactor was aerated at different rates to study the bio-oxidation of sulfide to elemental sulfur. The highest sulfate reduction efficiency (88%) was obtained with a feed sulfate concentration of 3.5 g L(-1), COD/sulfate mass ratio of 0.737, feed pH of 3.0 and HRT of 2 days without aeration in the 4th compartment. The corresponding COD removal efficiency was about 92%. The alkalinity produced in the sulfidogenic ethanol oxidation neutralized the acidic mine water from pH 3.0-4.5 to pH 7.0-8.0. Effluent soluble and total heavy metal concentrations were substantially reduced with removal efficiencies generally higher than 99%, except for Mn (25-77%). Limited aeration in the 4th compartment of ABR promoted incomplete oxidation of sulfide to elemental sulfur rather than complete oxidation to sulfate. Depending on the aeration rate and HRT, 32-74% of produced sulfide was oxidized to elemental sulfur. This study demonstrates that by optimizing operating conditions, sulfate reduction, metal removal, alkalinity generation, and excess sulfide oxidation can be achieved in a single ABR treating AMD. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Simultaneous denitrification and anaerobic digestion in GRAnular Bed Baffled Reactor (GRABBR)

    International Nuclear Information System (INIS)

    Baloch, M.I.; Akunna, J.C.

    2002-01-01

    This study elucidates the characteristics of compartmentalised anaerobic system seeded with UASB granules, called GRAanular Bed Baffled Reactor (GRABBR), for combined denitrification and anaerobic digestion processes. The reactor was used for the treatment of glucose enriched synthetic wastewater with various nitrate concentrations. The study was carried out with a 10 litre working volume GRABBR divided into 5 equal compartments operating at organic loading rate (OLR) of 20 kg COD/m 3 .d with a hydraulic retention time (HRT) of 6 hours. At these conditions, phase separation (between acidogenesis and methanogenesis) was created in the system and then the effect of varying nitrate concentrations (50-200 mg/l NO 3 -N) in the acidogenic zone (i.e. first compartment) was studied. Due to its unique compartmentalised design, denitrification was the major pathway for nitrate reduction with no noticeable dissimilatory nitrate reduction to ammonia (DNRA). More than 84% of all added nitrates were removed in the acidogenic zone, showing that acidogens possess high denitrifying capabilities. The denitrification rate increased with increase in nitrate concentration, with maximum value estimated as 175 mg NO 3 -N/l.h at influent nitrate concentration of 200 mg/l NO 3 -N in the acidogenic zone. Although nitrate addition resulted in lower methane production, COD removal efficiencies improved by up to 8% when compared with the reactor performance before nitrate addition. Furthermore, the alkalinity produced during denitrification improved the stability of the system by controlling the decrease in pH resulting from acidogenesis. The system encouraged simultaneous denitrification and anaerobic digestion in a single unit by accommodating denitrifiers in the early compartments and allowing methanogenesis to flourish in the downstream compartments of the system, thus minimising inhibition to methane producing bacteria by nitrates. (author)

  20. Treatment of low-strength soluble wastewater using an anaerobic baffled reactor (ABR).

    Science.gov (United States)

    Gopala Krishna, G V T; Kumar, Pramod; Kumar, Pradeep

    2009-01-01

    Treatment of low-strength soluble wastewater (COD approximately 500 mg/L) was studied using an eight chambered anaerobic baffled reactor (ABR). At pseudo steady-state (PSS), the average total and soluble COD values (COD(T) and COD(S)) at 8h hydraulic retention time (HRT) were found to be around 50 and 40 mg/L, respectively, while at 10h HRT average COD(T) and COD(S) values were of the order of 47 and 37 mg/L, respectively. COD and BOD (3 day, 27 degrees C) removal averaged more than 90%. Effluent conformed to Indian standards laid down for BOD (less than 30 mg/L). Reactor effluent characteristics exhibited very low values of standard deviation indicating excellent reactor stability at PSS in terms of effluent characteristics. Based on mass balance calculations, more than 60% of raw wastewater COD was estimated to be recovered as CH(4) in the gas phase. Compartment-wise profiles indicated that most of the BOD and COD got reduced in the initial compartments only. Sudden drop in pH (7.8-6.7) and formation of volatile fatty acids (VFA) (53-85 mg/L) were observed in the first compartment due to acidogenesis and acetogenesis. The pH increased and VFA concentration decreased longitudinally down the reactor. Residence time distribution (RTD) studies revealed that the flow pattern in the ABR was neither completely plug-flow nor perfectly mixed. Observations from scanning electron micrographs (SEM) suggest that distinct phase separation takes place in an ABR.

  1. Evaluation of decentralized treatment of sewage employing Upflow Septic Tank/Baffled Reactor (USBR) in developing countries

    Energy Technology Data Exchange (ETDEWEB)

    Sabry, Tarek, E-mail: tsabry@consultant.com [Ain Shams University, Department of Public Works Engineering, Abbasia, Cairo (Egypt)

    2010-02-15

    A new concept for a low-cost modified septic tank, named Upflow Septic Tank/Baffled Reactor (USBR), was constructed and tested in a small village in Egypt. During almost one year of continuous operation and monitoring, this system was found to have very satisfactory removal results, where the average results of COD, BOD, and TSS removal efficiencies were 84%, 81%, and 89%, respectively, and the results of the experiment proved that the second compartment (Anaerobic Baffled Reactor) was the main treatment unit in removing the pollutants during the start-up period and at the very early steady-state stage. However, after this period and during the steady-state operation conditions, the second compartment served as a polishing step. Also, it was observed that the USBR system was not affected by the imposed shock loads at the peak flow and organic periods. The results showed that the system is slightly influenced by the drop in the temperature. Decreasing in BOD and COD removal by factor of 9% was observed, when temperature decreases from the average of 35 deg. C in summer time (for the first 127 days) to the average of 22 deg. C in winter time (between day 252 and day 280). Whereas, the TSS removals were not affected by the drop in temperature. The results of the sewage flow variations during one year of operation were compared with Goodrich Formula to see the applicability of this equation in rural developing countries. Main finding of the work: The Upflow Septic Tank/Baffled Reactor system could become a promising alternative to the conventional treatment plants in rural developing countries.

  2. Installation of flow deflectors and wing baffles to reduce dead zone and enhance flashing light effect in an open raceway pond.

    Science.gov (United States)

    Zhang, Qinghua; Xue, Shengzhang; Yan, Chenghu; Wu, Xia; Wen, Shumei; Cong, Wei

    2015-12-01

    To reduce the dead zone and enhance the flashing light effect, a novel open raceway pond with flow deflectors and wing baffles was developed. The hydrodynamics and light characteristics in the novel open raceway pond were investigated using computational fluid dynamics. Results showed that, compared with the control pond, pressure loss in the flow channel of the pond with optimized flow deflectors decreased by 14.58%, average fluid velocity increased by 26.89% and dead zone decreased by 60.42%. With wing baffles built into the raceway pond, significant swirling flow was produced. Moreover, the period of average L/D cycle was shortened. In outdoor cultivation of freshwater Chlorella sp., the biomass concentration of Chlorella sp. cultivated in the raceway pond with wing baffles was 30.11% higher than that of the control pond. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Development of Magnetically Insulated Baffled Probe Cluster for Measurement of Energy Flux and Particle Flux in the Texas Helimak

    Science.gov (United States)

    Nogami, S. H.; Koepke, M.; Demidov, V.; Williams, C.; Gentle, K.

    2015-11-01

    Progress is reported in employing magnetically insulated baffled (MIB) probes in the Texas Helimak. Radial scans at the plasma edge of dc and ac space potential are presented. Like the Ball-Pen probe, the MIB probe shares the Langmuir probe simplicity and overcomes its shortcomings in the ability to make real-time measurements of plasma space potential, temperature, and energy/particle fluxes in magnetized plasma. By rotating the probe shaft to change the extent to which the baffle ``masks'' the probe collection area, the ratio between electron and ion probe current, and consequently the relative sensitivity of the floating-probe oscillations to space potential and electron/ion temperature, can be adjusted, thus allowing space potential fluctuations and electron/ion temperature fluctuations to be distinguished when measured at two different rotation angles. At the optimal rotation angle, the contribution of electron temperature and its fluctuations to the floating-potential measurement are eliminated and the space potential fluctuation phase is preserved. Support from DOE is gratefully acknowledged.

  4. Cultivation of Chlorella vulgaris in a pilot-scale sequential-baffled column photobioreactor for biomass and biodiesel production

    International Nuclear Information System (INIS)

    Lam, Man Kee; Lee, Keat Teong

    2014-01-01

    Highlights: • A new sequential baffled photobioreactor was developed to cultivate microalgae. • Organic fertilizer was used as the main nutrients source. • Negative energy balance was observed in producing microalgae biodiesel. - Abstract: Pilot-scale cultivation of Chlorella vulgaris in a 100 L sequential baffled photobioreactor was carried out in the present study. The highest biomass yield attained under indoor and outdoor environment was 0.52 g/L and 0.28 g/L, respectively. Although low microalgae biomass yield was attained under outdoor cultivation, however, the overall life cycle energy efficiency ratio was 3.3 times higher than the indoor cultivation. In addition, negative energy balance was observed in producing microalgae biodiesel under both indoor and outdoor cultivation. The minimum production cost of microalgae biodiesel was about RM 237/L (or USD 73.5/L), which was exceptionally high compared to the current petrol diesel price in Malaysia (RM 3.6/L or USD 1.1/L). On the other hand, the estimated production cost of dried microalgae biomass cultivated under outdoor environment was RM 46/kg (or USD 14.3/kg), which was lower than cultivation using chemical fertilizer (RM 111/kg or USD 34.4/kg) and current market price of Chlorella biomass (RM 145/kg or USD 45/kg)

  5. Passage and behaviour of cultured Lake Sturgeon in a prototype side-baffle fish ladder: I. Ladder hydraulics and fish ascent

    Science.gov (United States)

    Kynard, B.; Pugh, D.; Parker, T.

    2011-01-01

    Research and development of a fish ladder for sturgeons requires understanding ladder hydraulics and sturgeon behaviour in the ladder to insure the ladder is safe and provides effective passage. After years of research and development, we designed and constructed a full-scale prototype side-baffle ladder inside a spiral flume (38.3m long??1m wide??1m high) on a 6% (1:16.5) slope with a 1.92-m rise in elevation (bottom to top) to test use by sturgeons. Twenty-eight triangular side baffles, each extending part way across the flume, alternated from inside wall to outside wall down the ladder creating two major flow habitats: a continuous, sinusoidal flow down the ladder through the vertical openings of side-baffles and an eddy below each side baffle. Ascent and behaviour was observed on 22 cultured Lake Sturgeon=LS (Acipenser fulvescens) repeatedly tested in groups as juveniles (as small as 105.1cm TL, mean) or as adults (mean TL, 118cm) during four periods (fall 2002 and 2003; spring 2003 and 2007). Percent of juveniles entering the ladder that ascended to the top was greater in spring (72.7%) than in fall (40.9-45.5%) and 90.9% of 11 adults, which ascended as juveniles, ascended to the top. Six LS (27.3%) never swam to the top and seven (31.8%) swam to the top in all tests, indicating great variability among individuals for ascent drive. Some LS swam directly to the top in <1min, but most rested in an eddy during ascent. Juveniles swimming through outside wall baffle slots (mean velocity, 1.2ms-1) swam at 1.8-2.2body lengthss-1 and 3.2-3.3tail beatss-1, either at or approaching prolonged swimming speed. The side-baffle ladder was stream-like and provided key factors for a sturgeon ladder: a continuous flow and no full cross-channel walls, abundant eddies for resting, an acceptable water depth, and a water velocity fish could ascend swimming 2bls-1. A side-baffle ladder passes LS and other moderate-swimming fishes. ?? 2011 Blackwell Verlag, Berlin.

  6. Performance improvement of a hybrid air conditioning system using the indirect evaporative cooler with internal baffles as a pre-cooling unit

    Directory of Open Access Journals (Sweden)

    A.E. Kabeel

    2017-12-01

    Full Text Available In the present paper, the effects of the indirect evaporative cooler with internal baffle on the performance of the hybrid air conditioning system are numerically investigated. The hybrid air conditioning system contains two indirect evaporative coolers with internal baffle, one is utilized to pre-cool the air inlet to the desiccant wheel and the other is utilized to pre-cool the supply air inlet to the room. The effects of the inlet conditions of the process and reactivation air and working air ratio on the thermal performance of the hybrid air conditioning system have been analyzed. The results of this study show that in the hybrid air conditioning system for using the indirect evaporative cooler with internal baffle as a pre-cooling unit, the supply air temperature reduced by 21% and the coefficient of performance improved by 71% as compared to previous designs of the hybrid air conditioning system at the same inlet conditions. For increasing process air inlet temperature from 25 °C to 45 °C, supply air temperature increases from 12.7 °C to 14.2 °C, thermal COP increases from 1.87 to 2.84, and supply air relative humidity increases from 76.7% to 77.4%. Also, for increasing the reactivation air inlet temperature from 70 °C to 110 °C, supply air temperature dropped from 15.9 °C to 10.9 °C, supply air relative humidity dropped from 82.7% to 71.8%, and thermal COP dropped from 4.5 to 1.7. The recommended optimal air working ratio in the indirect evaporative cooler with internal baffle should be 0.15. Keywords: Desiccant material, Solar air collector, Evaporative cooler, Internal baffles, Air conditioning

  7. Assessing the removal of organic micropollutants by a novel baffled osmotic membrane bioreactor-microfiltration hybrid system

    KAUST Repository

    Pathak, Nirenkumar

    2018-04-14

    A novel approach was employed to study removal of organic micropollutants (OMPs) in a baffled osmotic membrane bioreactor-microfiltration (OMBR-MF) hybrid system under oxic–anoxic conditions. The performance of OMBR-MF system was examined employing three different draw solutes (DS), and three model OMPs. The highest forward osmosis (FO) membrane rejection was attained with atenolol (100 %) due to its higher molar mass and positive charge. With inorganic DS caffeine (94-100 %) revealed highest removal followed by atenolol (89-96 %) and atrazine (16-40 %) respectively. All three OMPs exhibited higher removal with organic DS as compared to inorganic DS. Significant anoxic removal was observed for atrazine under very different redox conditions with extended anoxic cycle time. This can be linked with possible development of different microbial consortia responsible for diverse enzymes secretion. Overall, the OMBR-MF process showed effective removal of total organic carbon (98%) and nutrients (phosphate 97% and total nitrogen 85%), respectively.

  8. The startup performance and microbial distribution of an anaerobic baffled reactor (ABR) treating medium-strength synthetic industrial wastewater.

    Science.gov (United States)

    Jiang, Hao; Nie, Hong; Ding, Jiangtao; Stinner, Walter; Sun, Kaixuan; Zhou, Hongjun

    2018-01-02

    In this study, an anaerobic baffled reactor (ABR) with seven chambers was applied to treat medium-strength synthetic industrial wastewater (MSIW). The performance of startup and shock test on treating MSIW was investigated. During the acclimation process, the chemical oxygen demand (COD) of MSIW gradually increased from 0 to 2,000 mg L -1 , and the COD removal finally reached 90%. At shock test, the feeding COD concentration increased by one-fifth and the reactor adapted very well with a COD removal of 82%. In a stable state, Comamonas, Smithella, Syntrophomonas and Pseudomonas were the main populations of bacteria, while the predominant methanogen was Methanobacterium. The results of chemical and microbiological analysis indicated the significant advantages of ABR, including buffering shocks, separating stages with matching microorganisms and promoting syntrophism. Meanwhile, the strategies for acclimation and operation were of great importance. Further work can test reactor performance in the treatment of actual industrial wastewater.

  9. Photo-fermentative hydrogen production in a 4m3 baffled reactor: Effects of hydraulic retention time.

    Science.gov (United States)

    Zhang, Quanguo; Lu, Chaoyang; Lee, Duu-Jong; Lee, Yu-Jen; Zhang, Zhiping; Zhou, Xuehua; Hu, Jianjun; Wang, Yi; Jiang, Danping; He, Chao; Zhang, Tian

    2017-09-01

    A 4m 3 pilot-scale baffled continuous-flow photoreactor with four sequential chambers (#1-#4) was established and tested to evaluate its photo-fermentative hydrogen production from wastewater that contains (10g/L glucose using a functional consortium at 30°C, under light with an intensity of 3000±200lux with a hydraulic retention time (HRT) of 24-72h. The hydrogen production rate and the broth characteristics varied significantly in the flow direction. The hydrogen production rate was highest in chamber #1, and lower in chambers #2-#4 at an HRT of 72h, while the peak production rate shifted to the latter chambers as the HRT was shortened. The overall H 2 production rate increased as HRT decreased, but was not consistent with the predictions that were based on the complete-mixing assumption. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Ultrasonic testing of core baffle former bolts of the core tanks of pressurised water reactors; Ultraschallpruefung von Kernumfassungsschrauben der Kernbehaelter von Druckwasserreaktoren

    Energy Technology Data Exchange (ETDEWEB)

    Bies, Christian M.; Alaerts, Louis; Bonitz, Frank W. [Westinghouse Electric Germany GmbH, Mannheim (Germany); Devlin, Russell S.; Minogue, Patrick [WesDyne International, Madison, PA (United States)

    2013-07-01

    This article presents the MIDAS VI testing robot used by Westinghouse / WesDyne. This is a remotely operated underwater vehicle which positions ultrasonic probes under camera control. This vehicle makes it possible to substantially reduce the time required for setting up and preparing ultrasonic tests on core baffle former bolts. It has also accelerated the test procedure itself. Test methods have also been developed for bolt types which were hitherto considered incapable of being tested. One of these methods is based on a phased array probe. The article also reports on experiences gained over the course of years in testing core baffle former bolts in European nuclear power plants using the SUPREEM testing robot.

  11. Performance of an Anaerobic Baffled Filter Reactor in the Treatment of Algae-Laden Water and the Contribution of Granular Sludge

    Directory of Open Access Journals (Sweden)

    Yaqin Yu

    2014-01-01

    Full Text Available This study investigated the performance and stability of an anaerobic baffled filter reactor in the treatment of algae-laden water from Taihu Lake at several organic loading rates. The study also evaluated the capability of soft filler to train granule sludge and improve the anaerobic environment and sludge activity in the anaerobic baffled reactor (ABR, thereby enhancing the treatment efficiency. The ABR consisted of five rectangular compartments, each of which was 120 cm long, 80 cm wide, 80 cm high, and packed with soft filler. The anaerobic baffled filter reactor was found to be an efficient reactor configuration for the treatment of algae-laden water. The reactor was operated at an organic loading rate of 1.5 kg chemical oxygen demand (COD/(m3d and an ambient temperature of 30 °C; under these conditions, the COD removal efficiency was 80% and the biogas production rate was 293 mL/(Ld. Moreover, the soft filler increased the biomass retention time and decreased the rate at which solids were washed out from the reactor, promoting an improved spatial distribution of the microbial communities within the compartments. Methanoregula, Methanobacteriaceae, Methanosaeta, Methanoculleu, and Thermogymnomonas were the dominant archaeal species in each compartment during an operational period of approximately 100 days. The protease activity in the reactor decreased longitudinally down the reactor from Compartments 1 to 5, whereas the activity of coenzyme F420 increased. The soft filler played a key role in successfully treating algae-laden water with the anaerobic baffled filter reactor.

  12. The energy-saving anaerobic baffled reactor membrane bioreactor (EABR-MBR) system for recycling wastewater from a high-rise building.

    Science.gov (United States)

    Ratanatamskul, Chavalit; Charoenphol, Chakraphan

    2015-01-01

    A novel energy-saving anaerobic baffled reactor-membrane bioreactor (EABR-MBR) system has been developed as a compact biological treatment system for reuse of water from a high-rise building. The anaerobic baffled reactor (ABR) compartment had five baffles and served as the anaerobic degradation zone, followed by the aerobic MBR compartment. The total operating hydraulic retention time (HRT) of the EABR-MBR system was 3 hours (2 hours for ABR compartment and very short HRT of 1 hour for aerobic MBR compartment). The wastewater came from the Charoen Wisawakam building. The results showed that treated effluent quality was quite good and highly promising for water reuse purposes. The average flux of the membrane was kept at 30 l/(m2h). The EABR-MBR system could remove chemical oxygen demand, total nitrogen and total phosphorus from building wastewater by more than 90%. Moreover, it was found that phosphorus concentration was rising in the ABR compartment due to the phosphorus release phenomenon, and then the concentration decreased rapidly in the aerobic MBR compartment due to the phosphorus uptake phenomenon. This implies that phosphorus-accumulating organisms inside the EABR-MBR system are responsible for biological phosphorus removal. The research suggests that the EABR-MBR system can be a promising system for water reuse and reclamation for high-rise building application in the near future.

  13. Biomethanation of vegetable market waste in an anaerobic baffled reactor: Effect of effluent recirculation and carbon mass balance analysis.

    Science.gov (United States)

    Gulhane, Madhuri; Khardenavis, Anshuman A; Karia, Sneha; Pandit, Prabhakar; Kanade, Gajanan S; Lokhande, Satish; Vaidya, Atul N; Purohit, Hemant J

    2016-09-01

    In the present study, feasibility of biomethanation of vegetable market waste in a 4-chambered anaerobic baffled reactor (ABR) was investigated at 30d hydraulic retention time and organic loading rate of 0.5gVS/L/d for one year. Indicators of process stability viz., butyrate/acetate and propionate/acetate ratios were consistent with phase separation in the different chambers, which remained unaltered even during recirculation of effluent. Chemical oxygen demand (COD) and volatile solids (VS) removal efficiencies were observed to be consistently high (above 90%). Corresponding biogas and methane yields of 0.7-0.8L/g VS added/d and 0.42-52L/g VS added/d respectively were among the highest reported in case of AD of vegetable waste in an ABR. Process efficiency of the ABR for vegetable waste methanation, which is indicated by carbon recovery factor showed that, nearly 96.7% of the input carbon considered for mass balance was accounted for in the product. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Electrochemically enhancement of the anaerobic baffled reactor performance as an appropriate technology for treatment of municipal wastewater in developing countries

    Directory of Open Access Journals (Sweden)

    Mohammad Aqaneghad

    2016-09-01

    Full Text Available This work was aimed at investigating the performance of the anaerobic baffled reactor (ABR for treatment of municipal wastewater at various hydraulic retention time (HRT. An effort was also made to improve the performance of ABR opting two strategies of effluent recirculation and electrochemical process integration. The mean steady-state removal of TSS, tCOD (total chemical oxygen demand, sCOD (soluble COD and BOD (biochemical oxygen demand at HRT of 48 h was 93 ± 1, 89 ± 1, 82 ± 1 and 92 ± 1%, respectively. The performance of ABR decreased when the HRT was decreased from 48 to 24 h. The effluent recirculation did not improve the performance of ABR. The integration of electrochemical process with the ABR (EABR using a pair of electrodes (steel or aluminum could enhance the removal of contaminants in the ABR. The EABR with steel electrodes at the current density of 0.1 mA cm−2 at the HRT of 24 h could decrease the concentrations of TSS, tCOD, BOD, sulfate and phosphate in the wastewater to the standard limits for discharge into surface water bodies. Therefore, EABR is a promising and efficient technology appropriate for domestic wastewater treatment mainly in the developing countries.

  15. EFFECT OF SULFATE LOADING RATE AND ORGANIC LOADING RATE ON ANAEROBIC BAFFLED REACTORS USED FOR TREATMENT OF SANITARY LANDFILL LEACHATES

    Directory of Open Access Journals (Sweden)

    O. Burbano-Figueroa

    2015-06-01

    Full Text Available AbstractThis study investigated the effect of organic loading rate (OLR and sulfate loading rate (SLR on landfill leachate treatment by a lab-scale anaerobic baffled reactor (ABR. Landfill leachate contained a concentration of organic matter between 3966 and 5090 mg COD.L-1 and no detectable amounts of sulfate. Reactors were started-up by feeding them with iron-sulfate at a SLR of 0.05 g SO42-.L-1.day-1 (4 weeks. Factorial design and response surface techniques were used to evaluate and optimize the effects of these operating variables on COD removal. ABRs were operated at OLRs ranging from 0.30 up to 6.84 g COD.L-1.day-1 by changes in influent volumetric flow. SO42- was added to the influent at a SRL from 0.06 to 0.13 g SO42-.L-1.day-1. The highest value of COD removal (66% was reached at an OLR of 3.58 g COD.L-1.day-1 and SLR of 0.09 g SO4-2.L-1.day-1 with a COD/SO4-2 ratio of 40. Under these conditions sulfate is mainly used for molecular hydrogen consumption while organic matter is preferentially degraded via methanogesis.

  16. Performance and spatial community succession of an anaerobic baffled reactor treating acetone-butanol-ethanol fermentation wastewater.

    Science.gov (United States)

    Zhang, Jun; Wei, Yongjun; Xiao, Wei; Zhou, Zhihua; Yan, Xing

    2011-08-01

    An anaerobic baffled reactor with four compartments (C1-C4) was successfully used for treatment of acetone-butanol-ethanol fermentation wastewater and methane production. The chemical oxygen demand (COD) removal efficiency was 88.2% with a CH(4) yield of 0.25L/(g COD(removed)) when organic loading rate (OLR) was 5.4kg CODm(-3)d(-1). C1 played the most important role in solvents (acetone, butanol and ethanol) and COD removal. Community structure of C2 was similar to that in C1 at stage 3 with higher OLR, but was similar to those in C3 and C4 at stages 1-2 with lower OLR. This community variation in C2 was consistent with its increased role in COD and solvent removal at stage 3. During community succession from C1 to C4 at stage 3, abundance of Firmicutes (especially OTUs ABRB07 and ABRB10) and Methanoculleus decreased, while Bacteroidetes and Methanocorpusculum became dominant. Thus, ABRB07 coupled with Methanoculleus and/or acetogen (ABRB10) may be key species for solvents degradation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Performance of Anaerobic Baffled Reactor with Three Compartments in Removal of COD of Wastewater of Chilly Sauce

    Directory of Open Access Journals (Sweden)

    Sumantri Indro

    2018-01-01

    Full Text Available The objective in this study is to examine the performance of each compartment of the number of compartments of anaerobic baffled reactor (ABR to the COD removal of the chilly sauce wastewater. Three-compartments of ABR were conducted in this experiment with the total volume of 60 l. ABR is very suitable for processing waste water with high content of COD. Wastewater conducted in this research is a degradable chilly sauce synthetic and high content of organic compounds. While the COD parameter is the main parameter to indicate the achievement of wastewater treatment plant. Stepwise in the research starting with the preparation of raw materials such as sample preparation of synthetic wastewater and preparation of activated sludge. Variable used is the time digestion in the ABR, sludge volume (50% and 70%, and initial COD concentrations (6000 – 14000 mg/L. The response is observed up to 7 days process. For a load of organic compounds, the first compartment has high degree of decomposition of organic compounds than 2nd and 3rd, it is shown that the COD removal the second and third compartment increase insignificantly compare the first compartment. As for the different height of the activated sludge indicated that for organic load of of 6170 mg/L up to 14265 mg/L, the first compartment has removal efficiency 79-73%, in the second compartment is 81-75%, 81-77% and third compartment.

  18. The behaviour of an anaerobic baffled reactor (ABR as the first stage in the biological treatment of hog farming effluents

    Directory of Open Access Journals (Sweden)

    F. Motteran

    2013-06-01

    Full Text Available This present paper reports a study of the efficiency of an anaerobic Baffled Reactor (ABR composed of three chambers working as the first stage of a biological treatment system for swine wastewater, over a period of 116 days. The average value of the volumetric organic loading rate (VOLR was 17.8 kgCODtotal m-3 d-1, the biological organic loading rates (BOLR based on total and filtered COD influents of 14381 mg L-1 and 3610 mg L-1, respectively, were: 1.3 kgCODtotal kgTVS d-1 and 0.98 kgCODfiltered kgTVS d-1, respectively, and the hydraulic loading rate (HLR was about 1.4 m³ m-3 d-1. The average removal efficiency for total COD was 80% at a hydraulic retention time (HRT of about 18 hours. The average alkalinity in the effluent was 3801 mgCaCO3 L-1. The average removal efficiencies for oil and grease and total soluble solids were 41% and 78%, respectively. The sludge granulation and biogas production in the ABR were quite different between the first and third compartment, showing a distinct microbial consortium in each chamber. Through this research it was confirmed that this type of reactor can be employed as the first stage in a system treating swine wastewater.

  19. Greenhouse wastewater treatment by baffled subsurface-flow constructed wetlands supplemented with flower straws as carbon source in different modes.

    Science.gov (United States)

    Chang, Junjun; Ma, Luyao; Chen, Jinquan; Lu, Yifeng; Wang, Xiaoyun

    2017-01-01

    Four laboratory-scale baffled subsurface-flow constructed wetlands (BSCWs) were established for the treatment of greenhouse wastewater containing high levels of nitrate and sulfate in the present study. Each BSCW microcosm involved a treatment zone and another post-treatment zone with a surface area ratio of 2:1. Evenly mixed straws of carnation and rose (w/w: 1/1), two common ornamental flowers, were supplemented as an organic carbon source into the treatment zone through a hydrolysis zone (CW 1), decentralized vertically installed perforated pipes (CW 2), and centralized pipes (CW 3 in the figures), except the blank system. Removals and transformations of nitrogen and sulfate as well as carbon release in the BSCWs were investigated and comparatively assessed. Results showed that the supplements of flower straws could greatly enhance both the nitrate and sulfate removals, and good performance was achieved during the beginning operation period of 30 days, followed by decline due to insufficient organic carbon supply. Nitrate removal efficiency was significantly higher and more stable compared to sulfate. The highest removal rates of nitrate and sulfate were achieved in the CW 3, with a mean value of 4.33 g NO 3 - -N·m -2  d -1 and 2.74 g SO 4 2- -S·m -2  d -1 , respectively, although the differences among the experimental microcosms were not statistically significant. However, almost the same TN removal rate (3.40-3.47 g N·m -2  d -1 ) was obtained due to the productions of NO 2 - -N and NH 4 + -N and leaching of organic N from the straws. High contents of organic carbon and colored substance were leached from the straws during the initial 10 days, but dropped rapidly to low levels, and could hardly determined after 30 days operation. The post-treatment zone could further eliminate various contaminants, but the capability was limited. Inorganic carbon (IC) concentration was detected to be a highly good indicator for the estimation of nitrate and

  20. Heat Flow Characteristics of a Newly-Designed Cooling System with Multi-Fans and Thermal Baffle in the Wheel Loader

    Directory of Open Access Journals (Sweden)

    Yidai Liao

    2017-03-01

    Full Text Available In the traditional cooling case, there is usually one fan in charge of heat transfer and airflow for all radiators. However, this seems to be inappropriate, or even insufficient, for modern construction machinery, as its overall heat flow density is increasing but thermal distribution is becoming uneven. In order to ensure that the machine works in a better condition, this paper employs a new cooling system with multiple fans and an independent cooling region. Based on the thermal flow and performance requirements, seven fans are divided into three groups. The independent cooling region is segregated from the engine region by a thermal baffle to avoid heat flowing into the engine region and inducing an overheat phenomenon. The experiment validates the efficiency of the new cooling system and accuracy of simulation. After validation, the simulation then analyzes heat transfer and flow characteristics of the cooling system, changing with different cross-sections in different axis directions, as well as different distances of the fan central axes. Finally, thermal baffles are set among the fan groups and provided a better cooling effect. The research realizes a multi-fan scheme with an independent cooling region in a wheel loader, which is a new, but high-efficiency, cooling system and will lead to a new change of various configurations and project designs in future construction machinery.

  1. 3-D numerical study of the effect of Reynolds number and baffle angle on heat transfer and pressure drop of turbulent flow of air through rectangular duct of very small height

    Directory of Open Access Journals (Sweden)

    Abhijit Paul

    2016-09-01

    Full Text Available Present article illustrates a computational study of three-dimensional steady state heat transfer and high turbulent flow characteristics through a rectangular duct with constant heat fluxed upper wall and single rectangular cross-sectioned baffle insertion at different angles. RNG k–ɛ model along with standard wall function based computations has been accomplished applying the finite volume method, and SIMPLE algorithm has been executed for solving the governing equations. For a Reynolds number, Re of 10,000 to 50,000, Prandtl Number, Pr of 0.707 and baffle angle, α of 30°, 60°, 90°, 120°, 150°, computational studies are executed, centred onto the hydraulic diameter, Dh, test section and hydrodynamic entry length of the duct. Flow field has been solved using Ansys Fluent 14.0 software. Study exposes that baffled rectangular duct has a higher average Nusselt number, Nu and Darcy friction factor, f compared to a smooth rectangular duct. Nu as well as f are found to be maximum at 90° baffle angle. Results illustrate that both α and Re play a significant role in heat transfer as well as flow characteristics and also effects TEF. The correctness of the results attained in this study is corroborated by comparing the results with those existing in the literature for smooth rectangular duct within a precision of ±2% for f and ±4% for Nu.

  2. Physical-chemical and operational performance of an anaerobic baffled reactor (ABR treating swine wastewater - 10.4025/actascitechnol.v32i4.7203

    Directory of Open Access Journals (Sweden)

    Erlon Lopes Pereira

    2010-12-01

    Full Text Available Since hog raising concentrates a huge amount of swine manure in small areas, it is considered by the environmental government organizations to be one of the most potentially pollutant activities. Therefore the main objective of this research was to evaluate by operational criteria and removal efficiency, the performance of a Anaerobic Baffled Reactor (ABR, working as a biological pre-treatment of swine culture effluents. The physical-chemical analyses carried out were: total COD, BOD5, total solids (TS, fix (TFS and volatiles (TVS, temperature, pH, total Kjeldahl nitrogen, phosphorus, total acidity and alkalinity. The ABR unit worked with an average efficiency of 65.2 and 76.2%, respectively, concerning total COD and BOD5, with a hydraulic retention time (HRT about 15 hours. The results for volumetric organic loading rate (VOLR, organic loading rate (OLR and hydraulic loading rate (HLR were: 4.46 kg BOD m-3 day-1; 1.81 kg BOD5 kg TVS-1 day-1 and 1.57 m3 m-3 day-1, respectively. The average efficiency of the whole treatment system for total COD and BOD5 removal were 66.5 and 77.8%, showing an adequate performance in removing the organic matter from swine wastewater.

  3. Performance evaluation of a natural treatment system for small communities, composed of a UASB reactor, maturation ponds (baffled and unbaffled) and a granular rock filter in series.

    Science.gov (United States)

    Dias, D F C; Passos, R G; Rodrigues, V A J; de Matos, M P; Santos, C R S; von Sperling, M

    2018-02-01

    Post-treatment of anaerobic reactor effluent with maturation ponds is a good option for small to medium-sized communities in tropical climates. The treatment line investigated, operating in Brazil, with an equivalent capacity to treat domestic sewage from 250 inhabitants, comprised a upflow anaerobic sludge blanket reactor followed by two shallow maturation ponds (unbaffled and baffled) and a granular rock filter (decreasing grain size) in series, requiring an area of only 1.5 m 2  inhabitant -1 . With an overall hydraulic retention time of only 6.7 days, the performance was excellent for a natural treatment system. Based on over two years of continuous monitoring, median removal efficiencies were: biochemical oxygen demand = 93%, chemical oxygen demand = 79%, total suspended solids = 87%, ammonia = 43% and Escherichia coli = 6.1 log units. The final effluent complied with European discharge standards and WHO guidelines for some forms of irrigation, and appeared to be a suitable alternative for treating domestic sewage for small communities in warm areas, especially in developing countries.

  4. On the effect of added impurity on crystal purity of urea in an oscillatory baffled crystallizer and a stirred tank crystallizer

    Science.gov (United States)

    McLachlan, Hannah; Ni, Xiong-Wei

    2016-05-01

    Previous work has indicated that crystals produced in oscillatory baffled crystallisers (OBC) from a relatively 'pure' starting environment gave statistically higher purities than that in stirred tank crystallisers (STC) under comparable conditions. In this work, a known amount of biuret (the impurity) was added to the 'pure' urea system and the results show that the OBC still produced higher purity crystals than the STC, although these purity values were statistically lower than from the 'pure' environment in both vessels. By evaluating crystallisation rates of both urea and biuret, we noticed that these rates are higher in the STC than in the OBC, which would have led to small crystals in the former vessel. The CSD data however gave the opposite result where the CSD is wider with more, large crystals in the STC than in the OBC, in particular in the presence of added impurity. These larger crystals are likely formed due to agglomeration coupled with incorporation of impurity, which leads to a lower purity.

  5. Performance of a novel baffled osmotic membrane bioreactor-microfiltration hybrid system under continuous operation for simultaneous nutrient removal and mitigation of brine discharge

    KAUST Repository

    Pathak, Nirenkumar

    2017-03-14

    The present study investigated the performance of an integrated osmotic and microfiltration membrane bioreactor system for wastewater treatment employing baffles in the reactor. Thus, this reactor design enables both aerobic and anoxic processes in an attempt to reduce the process footprint and energy costs associated with continuous aeration. The process performance was evaluated in terms of water flux, salinity build up in the bioreactor, organic and nutrient removal and microbial activity using synthetic reverse osmosis (RO) brine as draw solution (DS). The incorporation of MF membrane was effective in maintaining a reasonable salinity level (612-1434 mg/L) in the reactor which resulted in a much lower flux decline (i.e. 11.48 to 6.98 LMH) as compared to previous studies. The stable operation of the osmotic membrane bioreactor–forward osmosis (OMBR-FO) process resulted in an effective removal of both organic matter (97.84%) and nutrient (phosphate 87.36% and total nitrogen 94.28%), respectively.

  6. Evaluation of A Novel Split-Feeding Anaerobic/Oxic Baffled Reactor (A/OBR) For Foodwaste Anaerobic Digestate: Performance, Modeling and Bacterial Community

    Science.gov (United States)

    Wang, Shaojie; Peng, Liyu; Jiang, Yixin; Gikas, Petros; Zhu, Baoning; Su, Haijia

    2016-10-01

    To enhance the treatment efficiency from an anaerobic digester, a novel six-compartment anaerobic/oxic baffled reactor (A/OBR) was employed. Two kinds of split-feeding A/OBRs R2 and R3, with influent fed in the 1st, 3rd and 5th compartment of the reactor simultaneously at the respective ratios of 6:3:1 and 6:2:2, were compared with the regular-feeding reactor R1 when all influent was fed in the 1st compartment (control). Three aspects, the COD removal, the hydraulic characteristics and the bacterial community, were systematically investigated, compared and evaluated. The results indicated that R2 and R3 had similar tolerance to loading shock, but the R2 had the highest COD removal of 91.6% with a final effluent of 345 mg/L. The mixing patterns in both split-feeding reactors were intermediate between plug-flow and completely-mixed, with dead spaces between 8.17% and 8.35% compared with a 31.9% dead space in R1. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis revealed that the split-feeding strategy provided a higher bacterial diversity and more stable bacterial community than that in the regular-feeding strategy. Further analysis indicated that Firmicutes, Bacteroidetes, and Proteobacteria were the dominant bacteria, among which Firmicutes and Bacteroidetes might be responsible for organic matter degradation and Proteobacteria for nitrification and denitrification.

  7. Evaluation of A Novel Split-Feeding Anaerobic/Oxic Baffled Reactor (A/OBR) For Foodwaste Anaerobic Digestate: Performance, Modeling and Bacterial Community.

    Science.gov (United States)

    Wang, Shaojie; Peng, Liyu; Jiang, Yixin; Gikas, Petros; Zhu, Baoning; Su, Haijia

    2016-10-06

    To enhance the treatment efficiency from an anaerobic digester, a novel six-compartment anaerobic/oxic baffled reactor (A/OBR) was employed. Two kinds of split-feeding A/OBRs R2 and R3, with influent fed in the 1 st , 3 rd and 5 th compartment of the reactor simultaneously at the respective ratios of 6:3:1 and 6:2:2, were compared with the regular-feeding reactor R1 when all influent was fed in the 1 st compartment (control). Three aspects, the COD removal, the hydraulic characteristics and the bacterial community, were systematically investigated, compared and evaluated. The results indicated that R2 and R3 had similar tolerance to loading shock, but the R2 had the highest COD removal of 91.6% with a final effluent of 345 mg/L. The mixing patterns in both split-feeding reactors were intermediate between plug-flow and completely-mixed, with dead spaces between 8.17% and 8.35% compared with a 31.9% dead space in R1. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis revealed that the split-feeding strategy provided a higher bacterial diversity and more stable bacterial community than that in the regular-feeding strategy. Further analysis indicated that Firmicutes, Bacteroidetes, and Proteobacteria were the dominant bacteria, among which Firmicutes and Bacteroidetes might be responsible for organic matter degradation and Proteobacteria for nitrification and denitrification.

  8. Experimental investigation of heat transfer and pressure drop characteristics of non-Newtonian nanofluids flowing in the shell-side of a helical baffle heat exchanger with low-finned tubes

    Science.gov (United States)

    Tan, Yunkai; He, Zhenbin; Xu, Tao; Fang, Xiaoming; Gao, Xuenong; Zhang, Zhengguo

    2017-09-01

    An aqueous solution of Xanthan Gum (XG) at a weight fraction as high as 0.2% was used as the base liquid, the stable MWCNTs-dispersed non-Newtonian nanofluids at different weight factions of MWCNTs was prepared. The base fluid and all nanofluids show pseudoplastic (shear-thinning) rheological behavior. Experiments were performed to compare the shell-side forced convective heat transfer coefficient and pressure drop of non-Newtonian nanofluids to those of non-Newtonian base fluid in an integrally helical baffle heat exchanger with low-finned tubes. The experimental results showed that the enhancement of the convective heat transfer coefficient increases with an increase in the Peclet number and the nanoparticle concentration. For nanofluids with 1.0, 0.5 and 0.2 wt% of multi-walled carbon nanotubes (MWCNTs), the heat transfer coefficients respectively augmented by 24.3, 13.2 and 4.7% on average and the pressure drops become larger than those of the base fluid. The comprehensive thermal performance factor is higher than one and increases with an increasing weight fraction of MWCNTs. A remarkable heat transfer enhancement in the shell side of helical baffle heat exchanger with low-finned tubes can be obtained by adding MWCNTs into XG aqueous solution based on thermal resistance analysis. New correlations have been suggested for the shell-side friction coefficient and the Nusselt numbers of non-Newtonian nanofluids and give very good agreement with experimental data.

  9. Enhanced decolorization of azo dye in a small pilot-scale anaerobic baffled reactor coupled with biocatalyzed electrolysis system (ABR-BES): a design suitable for scaling-up.

    Science.gov (United States)

    Cui, Dan; Guo, Yu-Qi; Lee, Hyung-Sool; Wu, Wei-Min; Liang, Bin; Wang, Ai-Jie; Cheng, Hao-Yi

    2014-07-01

    A four-compartment anaerobic baffled reactor (ABR) incorporated with membrane-less biocatalyzed electrolysis system (BES) was tested for the treatment of azo dye (alizarin yellow R, AYR) wastewater (AYR, 200 mg L(-1); glucose, 1000 mg L(-1)). The ABR-BES was operated without and with external power supply to examine AYR reduction process and reductive intermediates with different external voltages (0.3, 0.5 and 0.7 V) and hydraulic retention times (HRT: 8, 6 and 4h). The decolorization efficiency in the ABR-BES (8h HRT, 0.5 V) was higher than that in ABR-BES without electrolysis, i.e. 95.1 ± 1.5% versus 86.9 ± 6.3%. Incorporation of BES with ABR accelerated the consumption of VFAs (mainly acetate) and attenuated biogas (methane) production. Higher power supply (0.7 V) enhanced AYR decolorization efficiency (96.4 ± 1.8%), VFAs removal, and current density (24.1 Am(-3) TCV). Shorter HRT increased volumetric AYR decolorization rates, but decreased AYR decolorization efficiency. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Farklı Hidrolik Bekletme Sürelerinin Anaerobik Perdeli Reaktörde Sülfat İndirgenmesi Üzerine Etkisi / Effect of Different Hydraulic Retention Time (HRT on Sulfate Reduction in Anaerobic Baffled Reactor

    Directory of Open Access Journals (Sweden)

    Şebnem ÖZDEMİR

    2012-12-01

    üresinin 2 gün olduğu çalışma koşullarında çıkış suyundaki KOİ ve SO4-2 verimleri %84 ile %88 olarak gözlemlenirken bekleme süresinin 0,5 gün olduğu çalışma koşullarında ise bu değer %80 ve %75 olarak gözlemlenmiştir. Ayrıca bekleme süresinin 2 gün olduğu çalışma koşullarında son bölmedeki sülfür oluşum verimi % 75 iken, bekleme süresi 0,5 güne indirildiğinde aynı bölmedeki sülfür oluşum veriminin %96’a çıktığı gözlemlenmiştir. Çıkarımlar ve Özgün Değer: Yapılan bu çalışma ile yüksek sülfat konsantrasyona sahip atıksuların arıtımında anaerobik perdeli reaktörün iyi bir alternatif olabileceği kanıtlanmıştır. Ayrıca çıkış sülfat ve sülfür konsantrasyonlarının değişen HBS’den etkilenmediği gözlenmiştir. Effect of Different Hydraulic Retention Time (HRT on Sulfate Reduction in Anaerobic Baffled Reactor Design and Method: The anaerobic baffled reactor (ABR is a modification of up-flow anaerobic sludge blanket (UASB reactor. A laboratory scale ABR was inoculated with an effluent of a full scale anaerobic digester located in Kayseri Wastewater Treatment Plant, Turkey. Before inoculation, the sludge was sieved to remove coarse materials. The ABR was 20 cm wide, 80 cm long, 20 cm deep and constructed from glass, with a working volume of 19 L. Reactor was divided into four equal 4.75 L compartments by vertical baffles, each compartment having down-comer and riser regions created by further vertical baffle. The lower parts of down-comer baffles were angled at 450 in order to direct the flow evenly through the riser. Ethanol and sulfate are consumed as electron donor and electron acceptor, respectively. Sulfate, dissolved sulfide, pH, alkalinity and chemical oxygen demand (COD have measured three times a week. Aim: There are varying structures and concentrations of sulfate compounds in natural waters. In addition, the amount of sulfate is higher in some industrial wastewaters In addition, some

  11. Vortex Shedding Inside a Baffled Air Duct

    Science.gov (United States)

    Davis, Philip; Kenny, R. Jeremy

    2010-01-01

    Common in the operation of both segmented and un-segmented large solid rocket motors is the occurrence of vortex shedding within the motor chamber. A portion of the energy within a shed vortex is converted to acoustic energy, potentially driving the longitudinal acoustic modes of the motor in a quasi-discrete fashion. This vortex shedding-acoustic mode excitation event occurs for every Reusable Solid Rocket Motor (RSRM) operation, giving rise to subsequent axial thrust oscillations. In order to better understand this vortex shedding/acoustic mode excitation phenomena, unsteady CFD simulations were run for both a test geometry and the full scale RSRM geometry. This paper covers the results from the subscale geometry runs, which were based on work focusing on the RSRM hydrodynamics. Unsteady CFD simulation parameters, including boundary conditions and post-processing returns, are reviewed. The results were further post-processed to identify active acoustic modes and vortex shedding characteristics. Probable locations for acoustic energy generation, and subsequent acoustic mode excitation, are discussed.

  12. Uso de leitos cultivados de fluxo vertical por batelada no pós-tratamento de efluente de reator anaeróbio compartimentado Post-treatment of effluent of anaerobic baffled reactor using batchwise vertical flow constructed wetland beds

    Directory of Open Access Journals (Sweden)

    Marcelo Mazzola

    2005-06-01

    Full Text Available Neste trabalho avaliou-se o desempenho de um Reator Anaeróbio Compartimentado (RAC de duas câmaras em série, seguido de três leitos cultivados (constructed wetlands de fluxo vertical por batelada. A unidade experimental, em escala piloto, foi instalada na Faculdade de Engenharia Agrícola - UNICAMP, Campinas, SP, Brasil. O volume total do reator era de 2,3 m³ (TDH de 12 h. O efluente do RAC foi tratado em três leitos, dois cultivados com macrófitas (gêneros Typha sp. e Eleocharis sp. e um utilizado como controle (não cultivado. Os leitos, com 2,0 m³ cada um e brita #2 (24 - 35 mm como meio suporte, operaram com fluxo vertical por batelada (com tempos de reação de 24, 48, 72 e 96 h. Na avaliação do RAC, observou-se tendência de estabilização dos parâmetros pH, alcalinidade, ácidos voláteis, sólidos sedimentáveis e suspensos totais, porém a remoção de DQO revelou-se limitada (50%. Nos leitos cultivados o aumento do tempo de reação (até 72 h foi acompanhado pelo aumento de remoção de turbidez, DQO, fósforo e nitrato. O melhor desempenho de remoção de fósforo total foi obtido no leito vegetado com Typha sp para os tempos de 72 e 96 h, respectivamente, de 30 e 25%.This study evaluated the performance of vertical constructed wetlands treating effluent of anaerobic baffled reactor. The anaerobic reactor volume was 2.3 m³; it was operated with daily flow of 4.6 m³ (12 hours Hydraulic Retention Time. The reactor effluent was split into three wetlands beds, two of them cultivated with macrophytes (Typha sp. and Eleocharis sp., and one control. The wetlands were operated as a batch reactor. The medium utilized was gravel, the size ranging from 7 to 12 mm. The reaction time for each cycle (filling - reaction - drainage was 24, 48, 72, and 96 h. The anaerobic reactor achieved the following removal rates: settable solids, 93%; suspended solids, 80%; and COD 39%. The increase in reaction time (up to 72 h for the constructed

  13. Enhancement of cell characteristics via baffle blocks in a proton ...

    Indian Academy of Sciences (India)

    Fuel cells are one type of device to produce green energy from fossil fuels in future applications. However, there are ... cell performance of a proton exchange membrane fuel cell (PEMFC) with a tapered flow channel design. ... oxygen consumption and liquid water production, so the cell performance is strongly dependent.

  14. Optimization of an idealized Y-Shaped Extracardiac Fontan Baffle

    Science.gov (United States)

    Yang, Weiguang; Feinstein, Jeffrey; Mohan Reddy, V.; Marsden, Alison

    2008-11-01

    Research has showed that vascular geometries can significantly impact hemodynamic performance, particularly in pediatric cardiology, where anatomy varies from one patient to another. In this study we optimize a newly proposed design for the Fontan procedure, a surgery used to treat single ventricle heart patients. The current Fontan procedure connects the inferior vena cava (IVC) to the pulmonary arteries (PA's) via a straight Gore-Tex tube, forming a T-shaped junction. In the Y-graft design, the IVC is connected to the left and right PAs by two branches. Initial studies on the Y-graft design showed an increase in efficiency and improvement in flow distribution compared to traditional designs in a single patient-specific model. We now optimize an idealized Y-graft model to refine the design prior to patient testing. A derivate-free optimization algorithm using Kriging surrogate functions and mesh adaptive direct search is coupled to a 3-D finite element Navier-Stokes solver. We will present optimization results for rest and exercise conditions and examine the influence of energy efficiency, wall shear stress, pulsatile flow, and flow distribution on the optimal design.

  15. The anaerobic baffled reactor (ABR): An appropriate technology for ...

    African Journals Online (AJOL)

    driniev

    Of the eubacteria, an average of 60% of cells hybridised by the EUB 388 probe were detected by eight family- or genera-specific probes, selected to identify the common micro-organisms that participate in the differ- ent processes of anaerobic digestion. No clear trends in the distri- bution of species were observed (Fig. 4).

  16. The developments of anaerobic baffled reactor for wastewater ...

    African Journals Online (AJOL)

    With the increasing deterioration of world water resources, configuring a technical and economic viable wastewater treatment and recycle technology to satisfying the increasing complexity of wastewater and stringent environmental regulation has been a great challenge over the past decades. Developing reliable ...

  17. Dynamics of tubes in fluid with tube-baffle interaction

    International Nuclear Information System (INIS)

    Chen, S.S.; Jendrzejczyk, J.A.; Wambsganss, M.W.

    1983-09-01

    Three series of tests are performed to evaluate the effects of tube to tube-support-plate (TSP) clearance on tube dynamic characteristics and instability phenomena for tube arrays in crossflow. Test results show that, for relatively large clearances, tubes may possess TSP-inactive modes in which the tubes rattle inside some of the tube-support-plate holes, and that the natural frequencies of TSP-inactive modes are lower than those of TSP-active modes, in which the support plates provide knife-edge type support. Tube response characteristics associated with TSP-inactive modes are sensitive to tube-to-TSP clearance, TSP thickness, excitation amplitude, tube alignment, and the fluid inside the clearance. In addition, tube response is intrinsically nonlinear, with the dominance of TSP-inactive or TSP-active modes depending on the magnitudes of different system parameters. In general, such a system is difficult to model; only a full-scale test can provide all the necessary characteristics. A tube array supported by TSPs with relatively large clearances may be subjected to dynamic instability in some of the TSP-inactive modes; tube response characteristics and impact forces on TSPs for a tube row are studied in detail in this report. Tube displacements associated with the instability of a TSP-inactive mode are small; however, impacts of the tube against TSPs may result in significant damage in a relatively short time. 52 figures

  18. Physical-chemical and operational performance of an anaerobic baffled reactor (ABR treating swine wastewater = Desempenho físico-químico e operacional de um reator anaeróbio compartimentado (RAC como tratamento biológico preliminar de efluentes de suinocultura

    Directory of Open Access Journals (Sweden)

    Erlon Lopes Pereira

    2010-10-01

    Full Text Available Since hog raising concentrates a huge amount of swine manure in smallareas, it is considered by the environmental government organizations to be one of the most potentially pollutant activities. Therefore the main objective of this research was to evaluate by operational criteria and removal efficiency, the performance of a Anaerobic Baffled Reactor (ABR, working as a biological pre-treatment of swine culture effluents. The physical-chemical analyses carried out were: total COD, BOD5, total solids (TS, fix (TFS and volatiles (TVS, temperature, pH, total Kjeldahl nitrogen, phosphorus, total acidity and alkalinity. The ABR unit worked with an average efficiency of 65.2 and 76.2%, respectively, concerning total COD and BOD5, with a hydraulic retention time (HRT about 15 hours. The results for volumetric organic loading rate (VOLR, organic loading rate (OLR andhydraulic loading rate (HLR were: 4.46 kg BOD m-3 day-1; 1.81 kg BOD5 kg TVS-1 day-1 and 1.57 m3 m-3 day-1, respectively. The average efficiency of the whole treatment system for total COD and BOD5 removal were 66.5 and 77.8%, showing an adequate performancein removing the organic matter from swine wastewater.A suinocultura por ser uma atividade pecuária concentradora de dejetos em pequenas áreas é considerada, pelos órgãos de gerência ambiental, como uma das atividades mais degradadoras do meio ambiente. Nesta pesquisa objetivou-se, por conseguinte, avaliar a utilização de um reator anaeróbio compartimentado (RAC, como unidade de prétratamento de um reator tipo UASB, em escala piloto, na adequação ambiental dos efluentes de suinocultura, avaliando critérios operacionais e a eficiência. As análises físico-químicasrealizadas foram: DQOtotal, DBO5, sólidos totais (ST, fixos (SF e voláteis (SV, temperatura, pH, nitrogênio total Kjeldahl, fósforo, acidez total e alcalinidade. A unidade RAC trabalhou com eficiência de 65,2 e 76,2% para a remoção de DQOtotal e DBO5

  19. Desempenho de processo anaeróbio em dois estágios (reator compartimentado seguido de reator UASB para tratamento de águas residuárias de suinocultura Performance of two-stage anaerobic process (baffled reactor (ABR followed by an upflow sludge blanket reactor (UASB treating swine wastewater

    Directory of Open Access Journals (Sweden)

    Gracie F. R. Fernandes

    2006-04-01

    Full Text Available Avaliou-se o efeito das águas residuárias de suinocultura com concentrações de sólidos suspensos totais em torno de 6.000 mg L-1 (DQOtotal variando de 7.557 a 11.640 mg L-1 no desempenho de processo anaeróbio em dois estágios compostos por reator compartimentado (ABR e reator de fluxo ascendente com manta de lodo (UASB, instalados em série, em escala-piloto (volumes de 530 e 120 L, respectivamente, submetidos a tempos de detenção hidráulica (TDH de 56 a 18 h no primeiro reator e de 13 a 4 h no segundo reator. As eficiências médias de remoção de DQOtotal variaram de 71,1 a 87,5% no reator ABR e de 41,5 a 50,1% no reator UASB, resultando em valores médios de 86,8 a 94,9% para o sistema de tratamento anaeróbio em dois estágios com carga orgânica volumétrica (COV, na faixa de 5,05 a 10,12 kg DQOtotal (m³ d-1, no reator ABR, e de 2,83 a 9,63 kg DQOtotal (m³ d-1, no reator UASB. As eficiências de remoção de SST e SSV foram da ordem de 95,6%. O teor de metano no biogás manteve-se acima de 70% para os dois reatores. A produção volumétrica de metano máxima de 0,755 m³ CH4 (m³ d-1 ocorreu no reator 1, com COV de 10,12 kg DQOtotal (m³ d-1 e TDH de 18 h. Os valores médios de pH variaram na faixa de 7,2 a 8,0 para os efluentes dos reatores 1 e 2. Os ácidos voláteis totais mantiveram-se estáveis com concentrações abaixo de 200 mg L-1. Com variações abruptas e acentuadas de concentrações de SST e DQOtotal do afluente, os reatores mantiveram as eficiências de remoção de DQO e sólidos suspensos, em torno de 70%, e a qualidade do biogás, com 80% de CH4.In this work it was evaluated the effect of swine wastewater with total suspended solid (TSS concentration around 6000 mg L-1 (CODtotal from 7557 to 11640 mg L-1 on the performance of two stage anaerobic process constituted of anaerobic baffled reactors (ABR and an upflow sludge blanket reactor (UASB installed in series, in pilot scale testing (volumes of 530 L and

  20. Remoção de matéria orgânica, de nutrientes e de coliformes no processo anaeróbio em dois estágios (reator compartimentado seguido de reator UASB para o tratamento de águas residuárias de suinocultura Organic matter, nutrients and coliforms removal in two-stage anaerobic process (anaerobic baffled reactor followed by UASB reactor for swine wastewater treatment

    Directory of Open Access Journals (Sweden)

    Mário S. de Abreu Neto

    2009-03-01

    Full Text Available Neste trabalho, avaliou-se o efeito das águas residuárias de suinocultura, com concentrações médias de sólidos suspensos totais variando de 4.591 a 13.001 mg L-1, no desempenho de processo anaeróbio, em dois estágios, compostos por reator compartimentado (ABR e reator de fluxo ascendente com manta de lodo (UASB, instalados em série, em escala- -piloto (volumes de 530 e 120 L, respectivamente, submetidos a tempos de detenção hidráulica (TDH de 60; 36 e 24 h no primeiro reator, e de 13,6; 8,2 e 5,4 h no segundo reator. As eficiências médias de remoção de DQOtotal variaram de 69 a 84% no reator ABR e de 39 a 58% no reator UASB, resultando em valores médios de 87 a 94% para o sistema de tratamento anaeróbio em dois estágios, com carga orgânica volumétrica (COV na faixa de 11,5 a 18,0 g DQOtotal (L d-1 no reator ABR, e de 4,2 a 13,4 g DQOtotal (L d-1 no reator UASB. A produção volumétrica máxima de metano de 0,227 m³ CH4 (m³ reator d-1 ocorreu no reator UASB, com COV de 10,6 g DQOtotal (L d-1 e TDH de 5,4 h. As maiores eficiências de remoção de coliformes totais e termotolerantes (99,7%, DQOdiss (94%, SST (96%, NTK (71%, P-total (61% e outros nutrientes, no sistema de tratamento anaeróbio em dois estágios, foram obtidas com o TDH de 73,6 h e temperatura climatológica média de 24,6 °C, aplicando-se a menor COV (de 11,5 g DQOtotal (L d-1 no reator ABR, e de 4,2 g DQOtotal (L d-1 no reator UASB com a maior concentração de SST do afluente (13.001 mg L-1.In this work it was evaluated the effect of swine wastewater with mean total suspended solid (TSS concentration ranging from 4.591 to 13.001 mg L-1 on the performance of the anaerobic process in two stages composed of anaerobic baffled reactors (ABR and an upflow sludge blanket reactor (UASB, installed in series, in pilot scale testing (volumes of 530 and 120 L, respectively and with hydraulic detention times (HDT of 60; 36 and 24 h in the ABR reactor and 13.6; 8.2 and

  1. Effect of the LHC Beam Screen Baffle on the Electron Cloud Buildup

    CERN Document Server

    Romano, Annalisa; Li, Kevin; Rumolo, Giovanni

    2016-01-01

    Electron Cloud (EC) has been identified as one of the major intensity-limiting factors in the CERN Large Hadron Collider (LHC). Due to the EC, an additional heat load is deposited on the perforated LHC beam screen, for which only a small cooling capacity is available. In order to preserve the superconducting state of the magnets, pumping slots shields were added on the outer side of the beam screens. In the framework of the design of the beam screens of the new HL-LHC triplets, the impact of these shields on the multipacting process was studied with macroparticle simulations. For this purpose multiple new features had to be introduced in the PyECLOUD code. This contribution will describe the implemented simulation model and summarize the outcome of this study.

  2. Evaluation Of Communal Wastewater Treatment Plant Operating Anaerobic Baffled Reactor And Biofilter

    Directory of Open Access Journals (Sweden)

    Evy Hendriarianti

    2016-02-01

    Full Text Available Construction of communal Waste Water Treatment Plant, WWTP in city of Malang since 1998 but until recently had never done an evaluation the performance. Communal WWTP performance evaluation is needed to see how far the efficiency of processing result. Until now, Environmental Agency Malang City only measure effluent from WWTP Communal  to know the suitability  with domestic wastewater quality standards. Effluent quality data in 2014 showed value above the quality standard of domestic wastewater from East Java Governor Regulation No. 72 in 2013 for parameters BOD and COD. WWTP Communal USRI research objects are on a six (6 locations by involving the user community during the planning, construction, operation and maintenance. Technology choice of ABR followed by a biofilter reactor with the stone media proved capable of processing organic matter of BOD and COD with the removal levels respectively by 78% -99% and 71% -99%. As for the parameters of TSS, NO3 and PO4 have the ranges of removal respectively by 56% -100%, (43% - 72%, (2% - 13%. Ratio BOD and COD in influent are low and ranged from 0.22 to 0.41. From the evaluation shows that high organic matter concentrations in influent along with the HRT and operation time high will result in a higher removal level

  3. Study of Anti-Vortex Baffle Effect in Suppressing Swirling Flow in LOX Tank

    Science.gov (United States)

    Yang, H. Q.; Peugeot, John

    2011-01-01

    Experimental results describing the hydraulic dynamic pump transfer matrix (Yp) for a cavitating J-2X oxidizer turbopump inducer+impeller tested in subscale waterflow are presented. The transfer function is required for integrated vehicle pogo stability analysis as well as optimization of local inducer pumping stability. Dynamic transfer functions across widely varying pump hydrodynamic inlet conditions are extracted from measured data in conjunction with 1D-model based corrections. Derived Dynamic transfer functions are initially interpreted relative to traditional Pogo pump equations. Water-to-liquid oxygen scaling of measured cavitation characteristics are discussed. Comparison of key dynamic transfer matrix terms derived from waterflow testing are made with those implemented in preliminary Ares Upper Stage Pogo stability modeling. Alternate cavitating pump hydraulic dynamic equations are suggested which better reflect frequency dependencies of measured transfer matrices.

  4. Numerical Analysis for un-baffled Mixing Tank Agitated by Two Types of Impellers

    Directory of Open Access Journals (Sweden)

    Ammar Ashour Akesh

    2018-02-01

    Full Text Available The effect of impeller flow type and rotation speed on the fluid in mixing tank design under standard configurations investigated to analyses the fluid velocity, turbulent intensity and path lines. In this theoretical study, the fluid motion inside the mixing tank was investigated by solving Navier-Stokes equation and standard k-ε turbulent model in 3-dimensions, for incompressible and turbulent flow. Two types of flow with three types of impellers were investigated, axial-flow with (Lightnin200 and generic impellers and radial-flow with (Rushton turbine. All impellers evaluated under rotation velocity variation between 10 – 115 rpm. The results showed a direct proportional relationship between the impeller and turbine rotation speed with the fluid velocity in mixing vessel. Also, this case matches with the turbulent intensity and path lines.

  5. The Design, Construction and Test of stray light suppression baffles for the CHAMP satellite

    DEFF Research Database (Denmark)

    Jørgensen, John Leif

    1997-01-01

    The Advanced Stellar Compass, to be delivered from IAU to the CHAMP project, requires some kind of stray-light suppressing shade to be mounted in front of the lens, in order to minimize the thermal impact and to maximize the performance envelope when subjected to non-stellar external light sources...

  6. Process and device for closing the apertures of a nuclear reactor core baffle formers

    International Nuclear Information System (INIS)

    Chevereau, G.

    1990-01-01

    The blades of at least two sets of blades along a shaft have bearing pads on the apertures of the formers with a length superior at the apertures radius. This device produces a transversal stagger of the shaft in two different directions in two zones of the shaft. It is possible to put in place and fix the closing device by an axial thrust [fr

  7. Study of fluid flow in baffled vessels stirred by a Rushton standard impeller

    Czech Academy of Sciences Publication Activity Database

    Chára, Zdeněk; Kysela, Bohuš; Konfršt, Jiří; Fořt, I.

    2016-01-01

    Roč. 272, č. 3 (2016), s. 614-628 ISSN 0096-3003 R&D Projects: GA ČR GAP101/12/2274 Institutional support: RVO:67985874 Keywords : trailing vortices * rushton impeller * PIV measurements * DES * numerical simulation Subject RIV: BK - Fluid Dynamics Impact factor: 1.738, year: 2016

  8. An exploratory study of three-dimensional MP-PIC-based simulation of bubbling fluidized beds with and without baffles

    DEFF Research Database (Denmark)

    Yang, Shuai; Wu, Hao; Lin, Weigang

    2018-01-01

    In this study, the flow characteristics of Geldart A particles in a bubbling fluidized bed with and without perforated plates were simulated by the multiphase particle-in-cell (MP-PIC)-based Eulerian-Lagrangian method. A modified structure-based drag model was developed based on our previous work...

  9. A Numerical Study of the Impact of Radial Baffles in solid Bowl Centrifuges Using computational Fluid Dynamics

    OpenAIRE

    Romani, Xiana; Nirschl, Hermann

    2010-01-01

    Centrifugal separation equipment, such as solid bowl centrifuges, is used to carry out an effective separation of fine particles from industrial fluids. Knowledge of the streams and sedimentation behavior inside solid bowl centrifuges is necessary to determine the geometry and the process parameters that lead to an optimal performance. Regarding a given industrial centrifuge geometry, a grid was built to calculate numerically the multiphase flow of water, air, and particles with a computation...

  10. Fractional pressure measurements inside of the divertor baffling at W7-X with a spectroscopically assisted Penning gauge

    Science.gov (United States)

    Kremeyer, Thierry; Schmitz, Oliver; Wenzel, Uwe; Flesch, Kurt; W7-X Team

    2017-10-01

    Studies of helium exhaust from stellarator divertors is important to qualify sufficient helium exhaust for future reactors. Penning gauges assisted by spectroscopy were used to measure total neutral pressure and to resolve the D and He partial pressures. A generic feasibility test at W7-X gave successful measurements of the total as well as the fractional neutral pressures of He and H. A first prototype of a new Penning gauge probe head has been tested at UW Madison at 240 mT as well as at the PAX magnet at IPP Greifswald, Germany at 3 T and shows a near linear power law scaling between current and pressure: I = C *Pn with n = 1.0 - 1.2 for the 240 mT case and 2.3 - 2.8 for the 3 T case. Pressure measurements were achieved starting at 10-2 mbar and down to 10-6 mbar. With the new probe head, it was possible to increase the time resolution of the spectroscopically assisted fractional neutral pressure measurements to up to 1MHz. This system is now implemented at three poloidal positions at one toroidal location in W7-X and is ready for measurements. This work was funded in part by the Department of Energy under Grants DE-SC0012315 and DE-SC0014210 and from EUROfusion under Grant No 633053.

  11. Modeling the dynamic volatile fatty acids profiles with pH and hydraulic retention time in an anaerobic baffled reactor during the startup period.

    Science.gov (United States)

    Shi, En; Li, Jianzheng; Leu, Shao-Yuan; Antwi, Philip

    2016-12-01

    To predict the dynamic profiles in volatile fatty acids (VFAs) with pH and hydraulic retention time (HRT) during the startup of a 4-compartment ABR, a mathematical model was constructed by introducing pH and thermodynamic inhibition functions into the biochemical processes derived from the ADM1. The calibration of inhibition parameter for propionate uptake effectively improved the prediction accuracy of VFAs. The developed model could simulate the VFAs profiles very well no matter the observable change of pH or/and HRT. The simulation results indicated that both H 2 -producing acetogenesis and methanogenesis in the ABR would be inhibited with a pH less than 4.61, and the propionate oxidation could be thermodynamically restricted even with a neutral pH. A decreased HRT would enhanced the acidogenesis and H 2 -producing acetogenesis in the first 3 compartments, but no observable increase in effluent VFAs could be found due to the synchronously enhanced methanogenesis in the last compartment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Experimental study of fuel bundle vibrations with rods subjected to mixed axial flow and cross-flow provided by a narrow gap (baffle jetting interaction)

    International Nuclear Information System (INIS)

    Boulanger, P.; Jacques, Y.; Fardeau, P.; Barbier, D.; Rigaudeau, J.

    1997-01-01

    The Hydraulic Core Laboratory (LHC) performs experimental studies of PWR fuel assembly mechanical behaviour submitted to representative flows in PWR core. Cross-flows prove particularly troublesome by generating on rods, in special cases, vibratory levels high enough to induce early grid to rod fretting. The fluid-structure interaction under mixed axial and cross-flow is also a major topic for analysis. The authors present a test loop devoted to the mixed axial-cross-flow fluid-structure interaction on representative half-scale mockup which is able to simulate, under ambient conditions, any complex flow (direction and flow rates) representative of PWR core flows. Despite its reduced size, the mockup retains the overall structure of a PWR fuel assembly. Rods displacement/velocity and velocity flow field are measured by laser techniques

  13. Production of bioenergy in anaerobic baffled reactor (ABR) and sludge blanket (UASB) in the treatment os swine waste water; Producao de bioenergia em reatores anaerobios compartimentado (RAC) e de manta de lodo (UASB) no tratamento de efluentes de suinocultura

    Energy Technology Data Exchange (ETDEWEB)

    Moterani, Fabricio; Pereira, Erlon Lopes; Campos, Claudio M.M. [Universidade Federal de Lavras (DEG/UFLA), MG (Brazil). Dept. de Engenharia], email: fabricio_moterani@yahoo.com.br

    2011-07-01

    The biogas is obtained in the processes of degradation of organic matter by the action of bacterial consortium in the environment. The aim of this study was to evaluate the biogas production in anaerobic UASB and ABR in swine wastewater treatment. For this we used the theoretical estimated and actual production of biogas measured by anaerobic gasometers installed in the units. Methane was determined by gas chromatography (GC) and its theoretical output was 66 LCH4 kgSVT d{sup -1} and 11.9 LCH4 kgSVT d{sup -1} and 24.7 m{sup 3} d{sup -1} and 5.4 m{sup 3} d{sup -1} to ABR and UASB, respectively. Regarding the actual production of biogas in the reactor provided by the gas tank, found the values of 1,166.4 m{sup 3}; 0.1 m{sup 3}; 27.4 m{sup 3} and 12,598.5 m{sup 3} of biogas for compartments 1, 2 and 3 and ABR for the UASB reactor, respectively, totaling, production of 13,792.4 m{sup 3} in the units together, with an average of 113 m{sup 3} of biogas per day. But, it concludes with this research that the use of effluent from produce energy through biogas in swine farming is effective, which can be used in rural productive system itself. (author)

  14. Nonlinear Sloshing and the Coupled Dynamics of Liquid Propellants and Spacecraft

    Science.gov (United States)

    1992-02-29

    asdsytmshaerahr oplx isinreureenswhc dnd h ofli theu~ liquido slohtng for hreedimesionl liuid Loshn iutio. Flid ynmic and. fudlaig nldn oa oc n impc...VERTICAL EXCITATION AND ITS CONTROL BY BAFFLES ............................................ 29 CHAPTER 4 THE CONTROL OF LATERAL SLOSHING IN RECTANGULAR...TANK - THE EFFECTIVENESS OF FIXED BAFFLE AND MOVING BAFFLE WITH FEEDBACK CONTROL ............................................. 32 CHAPTER 5 THE IMPACT

  15. Fouling resistant membrane spacers

    KAUST Repository

    Ghaffour, Noreddine

    2017-10-12

    Disclosed herein are spacers having baffle designs and perforations for efficiently and effectively separating one or more membrane layers a membrane filtration system. The spacer (504) includes a body (524) formed at least in part by baffles (520) that are interconnected, and the baffles define boundaries of openings or apertures (525) through a thickness direction of the body of the spacer. Alternatively or additionally, passages or perforations (526A, 526B) may be present in the spacer layer or baffles for fluid flow there through, with the passages and baffles having a numerous different shapes and sizes.

  16. REDISTRIBUTOR FOR LIQUID-LIQUID EXTRACTION COLUMNS

    Science.gov (United States)

    Bradley, J.G.

    1957-10-29

    An improved baffle plate construction to intimately mix immiscible liquid solvents for solvent extraction processes in a liquid-liquid pulse column is described. To prevent the light and heavy liquids from forming separate continuous homogeneous vertical channels through sections of the column, a baffle having radially placed rectangular louvers with deflection plates opening upon alternate sides of the baffle is placed in the column, normal to the axis. This improvement substantially completely reduces strippiig losses due to poor mixing.

  17. Self-defrosting recuperative air-to-air heat exchanger

    Science.gov (United States)

    Drake, Richard L.

    1993-01-01

    A heat exchanger includes a stationary spirally or concentrically wound heat exchanger core with rotating baffles on upper and lower ends thereof. The rotating baffles include rotating inlets and outlets which are in communication with respective fixed inlets and outlets via annuli. The rotation of the baffles causes a concurrent rotation of the temperature distribution within the stationary exchanger core, thereby preventing frost build-up in some applications and preventing the formation of hot spots in other applications.

  18. Numerical Study of Liquid Sloshing on Anti-sloshing Device Using Open Cell Metal Foams in Oil Tank

    Science.gov (United States)

    Zhang, Y.; Qu, Z. G.; Tao, W. Q.; Lu, T. J.

    2010-03-01

    A new baffle structure design named open-cell metal foams baffle for anti-sloshing device in oil tank is presented in this study. Numerical simulation study on the liquid sloshing with various baffles is carried out using FLUENT with the volume-of-fluid (VOF) model. Four types of baffles were studied, namely non-baffle (type A), conventional parallel-baffle (type B), cross-baffle (type C) and open- cell metal foams baffles (type D). The oil velocity distribution, centroid and oil occupancy in the sloshing process is revealed in the case of vehicle speeding up and turning respectively. It is found that type D reduce velocity of oil, increase the value of oil occupancy in the suction pipe entrance of the oil tank and lower the centroid of oil obviously comparing with the other types. As for the same open-cell metal foam pore density, lower open-cell metal foam porosity has much better effect of inhibition of liquid sloshing, but there is little deviation among different porosity for the absolute value. Moreover, according to the same porosity, the oil centroid can be lowered obviously with the increase of pore density. The results of type D show practical significance and referable guideline for baffles design to improve the safety and stability of vehicle.

  19. Automatic coolant flow control device for a nuclear reactor assembly

    Science.gov (United States)

    Hutter, E.

    1984-01-27

    A device which controls coolant flow through a nuclear reactor assembly comprises a baffle means at the exit end of said assembly having a plurality of orifices, and a bimetallic member in operative relation to the baffle means such that at increased temperatures said bimetallic member deforms to unblock some of said orifices and allow increased coolant flow therethrough.

  20. A numerical study of momentum and forced convection heat transfer ...

    African Journals Online (AJOL)

    diamond-shaped baffles and found that the diamond baffle with half apex angle of 5-10° performs slightly better than ..... physics applications. In this simulation, The. Commercial CFD software FLUENT 6.3, details of which can be found in Reference [22], was used to simulate the fluid flow and temperature fields. As a part of ...

  1. Reduced-Order Models for Acoustic Response Prediction

    Science.gov (United States)

    2011-07-01

    written in ASCII format as a "punch" file. Implementation with Abaqus required a series of Python [35] programs to translate the data from the binary...66. Abaqus acoustic pressure results of the clamped, baffled plate .......................................106 67. Real part of complex first mode of...107 68. Baffled plate center displacement response to initial pressure in Abaqus .......................108 69. Abaqus acoustic pressure of

  2. Effect of recycle on treatment of aircraft de-icing fluid in an anaerobic ...

    African Journals Online (AJOL)

    Aircraft de-icing fluid at 7 000 mg COD/ℓ was successfully treated in an anaerobic baffled reactor operated with and without recycle at volumetric organic loading rate of between 4 and 11 g COD/ℓreactor·d. Reactor recycle was found to improve reactor performance. The anaerobic baffled reactor operated with a 6:1 recycle ...

  3. Utilization of Additive Manufacturing for Aerospace Heat Exchangers

    Science.gov (United States)

    2016-02-29

    when compared to traditional manufacturing methods, the potential to improve part performance through innovative designs that may be economically ...single counterpart. The doughnut and disk type baffles have small perforations between tube holes to allow a combination of cross flow and...pure longitudinal flow. In addition, doughnut and disk type baffles minimize tube-to-tube temperature differences. Because of these attributes

  4. Experimental and numerical investigations of flow through free ...

    African Journals Online (AJOL)

    Studying the flow patterns and behaviour of double baffled gates under different flow heads is important to improve their performance, which could help in widening the range of their application. In the present study, physical and numerical investigations were conducted on the double baffled gate. A 3D Acoustic Doppler ...

  5. 10 CFR Appendix B to Part 110 - Illustrative List of Gas Centrifuge Enrichment Plant Components Under NRC's Export Licensing...

    Science.gov (United States)

    2010-01-01

    ... the centrifuges or to control the plant. Normally UF6 is evaporated from the solid using heated... disc-shaped baffle(s) and a stationary tube arrangement for feeding and extracting UF6 gas and... main separation chamber and, in some cases, to assist the UF6 gas circulation within the main...

  6. High performance internal reforming unit for high temperature fuel cells

    Science.gov (United States)

    Ma, Zhiwen [Sandy Hook, CT; Venkataraman, Ramakrishnan [New Milford, CT; Novacco, Lawrence J [Brookfield, CT

    2008-10-07

    A fuel reformer having an enclosure with first and second opposing surfaces, a sidewall connecting the first and second opposing surfaces and an inlet port and an outlet port in the sidewall. A plate assembly supporting a catalyst and baffles are also disposed in the enclosure. A main baffle extends into the enclosure from a point of the sidewall between the inlet and outlet ports. The main baffle cooperates with the enclosure and the plate assembly to establish a path for the flow of fuel gas through the reformer from the inlet port to the outlet port. At least a first directing baffle extends in the enclosure from one of the sidewall and the main baffle and cooperates with the plate assembly and the enclosure to alter the gas flow path. Desired graded catalyst loading pattern has been defined for optimized thermal management for the internal reforming high temperature fuel cells so as to achieve high cell performance.

  7. Physicochemical study of pH, alkalinity and total acidity in a system composed of Anaerobic Baffled Reactor in series with Upflow Anaerobic Sludge Blanket reactor in the treatment of pig farming wastewater - doi: 10.4025/actascitechnol.v35i3.14069

    Directory of Open Access Journals (Sweden)

    Erlon Lopes Pereira

    2013-06-01

    Full Text Available The anaerobic digestion efficiency varies according to several factors, such as: substrate carbon / nitrogen ratio, temperature, pH, alkalinity, and acidity. The main objective of this study was to describe the behavior of pH, alkalinity and total acidity of the affluent and effluent of a swine wastewater treatment system, in order to better understand the physicochemical process. The pH was measured immediately after collecting, and the methods of Jenkins et al. (1983 and Ripley et al. (1986 were used for quantifying the alkalinity, and the potentiometric method, for the acidity. The treatment system worked without large pH variation concerning the affluent and effluent of each unit, indicating good buffering conditions. The Ripley ratio (IA / PA is characteristic for each effluent and dependent on the stage at which the reactor is working, and was determined as 1.96 for hydrolysis and acidification tank, 1.56 for reactors working on first stage (ABR, and 1.44 for reactors working on second stage (UASB.  

  8. Hydrodynamic characteristics and microalgae cultivation in a novel flat-plate photobioreactor.

    Science.gov (United States)

    Zhang, Qing H; Wu, Xia; Xue, Sheng Z; Wang, Zhi H; Yan, Cheng H; Cong, Wei

    2013-01-01

    Flat-plate photobioreactors (FPPBRs) are widely reported for cultivation of microalgae. In this work, a novel FPPBR mounted with inclined baffles was developed, which can make the fluid produce a "spirality" flow. The flow field and cell trajectory in the photobioreactor were investigated by using computational fluid dynamics. In addition, the cell trajectory was analyzed using a Fast Fourier transformation. The influence of height of the baffles, the angle α between the inclined baffle and fluid inlet flow direction (z), and the fluid inlet velocity on the frequency of flashing light effect and pressure drop were examined to optimize the structure parameters of the inclined baffles and operating conditions of the photobioreactor. The results showed that with inclined baffles built-in, significant swirl flow could be generated in the FPPBR. In this way, the flashing light effect for microalgal cell could also be achieved and the photosynthesis efficiency of microalgae could be promoted. In outdoor cultivation of freshwater Chlorella sp., the maximum biomass productivity of Chlorella sp. cultivated in the photobioreactor with inclined baffles was 29.94% higher than that of the photobioreactor without inclined baffles. Copyright © 2012 American Institute of Chemical Engineers (AIChE).

  9. Characteristics of surface sound pressure and absorption of a finite impedance strip for a grazing incident plane wave.

    Science.gov (United States)

    Sum, K S; Pan, J

    2007-07-01

    Distributions of sound pressure and intensity on the surface of a flat impedance strip flush-mounted on a rigid baffle are studied for a grazing incident plane wave. The distributions are obtained by superimposing the unperturbed wave (the specularly reflected wave as if the strip is rigid plus the incident wave) with the radiated wave from the surface vibration of the strip excited by the unperturbed pressure. The radiated pressure interferes with the unperturbed pressure and distorts the propagating plane wave. When the plane wave propagates in the baffle-strip-baffle direction, it encounters discontinuities in acoustical impedance at the baffle-strip and strip-baffle interfaces. The radiated pressure is highest around the baffle-strip interface, but decreases toward the strip-baffle interface where the plane wave distortion reduces accordingly. As the unperturbed and radiated waves have different magnitudes and superimpose out of phase, the surface pressure and intensity increase across the strip in the plane wave propagation direction. Therefore, the surface absorption of the strip is nonzero and nonuniform. This paper provides an understanding of the surface pressure and intensity behaviors of a finite impedance strip for a grazing incident plane wave, and of how the distributed intensity determines the sound absorption coefficient of the strip.

  10. New cathode design boron lined proportional counters for neutron area monitoring application

    International Nuclear Information System (INIS)

    Dighe, Priyamvada M.

    2007-01-01

    A new cathode design boron lined proportional counter of 26mm IDx100mm sensitive length SS304 cathode has been developed with boron-coated baffles separated by 3mm spacers inserted in the sensitive volume perpendicular to the axis. The baffles and the spacers were coated with indigenously available 27.7% enriched 10 B. The introduction of baffles enhanced the boron coated surface area by a factor of 2.8. Tests in 120nv thermal neutron flux show that the counter has 0.84cps/nv thermal neutron sensitivity, which shows enhancement in the sensitivity by a factor of 2.78 due to baffle structure. For comparison standard cylindrical cathode geometry counter coated with 92% enriched 10 B on its inner wall with a coating thickness of 0.8mg/cm 2 is developed with same outer dimensions for neutron area monitoring applications. The counter has 1cps/nv thermal neutron sensitivity. Comparative tests carried out on counters with and without baffle structure show that the baffles enhance the neutron sensitivity and in 2kR/h gamma background the effect of gamma pile up is similar on both the counters. The variation in cathode internal diameter due to baffle structure gives higher voltage plateau slope (2.8%/10V) as compared to conventional cylindrical geometry counter (1.2%/10V). The usability of boron lined counters for neutron area monitoring applications for the cylindrical geometry counter has been studied

  11. Ventilation and exhaust ducts for dry storage facilities with self-heating radioactive materials

    International Nuclear Information System (INIS)

    Knappe, O.; Hame, W.

    1986-01-01

    The storage facilities are cooled by natural convection. In order to achieve this, the air inlet and outlet openings or ducts for the PWR and BWR fuel store are arranged at the level of the roof structure. There are two types of air inlet openings arranged on top and on the sides respectively but having got common inlet ducts. Air supply is improved by means of baffle noses, baffle edges, and baffle plates. The exhaust air ducts terminate near the roof structure, the openings having got dropping edges, protective sills and separating plates. (orig./PW)

  12. An Investigation of the Ranger V-770-8 Engine Installation for the Edo XOSE-1 Airplane I : Cooling

    Science.gov (United States)

    Emmons, M. Arnold; Conway, Robert N.

    1945-01-01

    Engine temperature data and cooling correlating analyses of the engine and oil cooler are presented in connection with an investigation of the cowling and cooling of the ranger V-770-8 engine installation in the Edo XOSE-1 airplane. Three types of baffles were installed in the course of the tests: the conventional, the turbulent-flow, and the NACA diffuser baffles. Each of the types was of merit in cooling a different region on the cylinder. Incorporation of the best features of the three types into one baffle, a method which appears to be feasible, would provide improvements in cylinder cooling.

  13. Phase change liquid purifier and pump

    Science.gov (United States)

    Steinhour, Leif Alexi

    2017-05-23

    Systems, methods, and apparatus are provided for purifying and pumping liquids, and more particularly, for purifying and pumping water. The apparatus includes a chamber including a top portion and a bottom portion. A surface configured to be heated is proximate the bottom portion of the chamber. A baffle is disposed within the chamber and above the surface. The baffle is disposed at an angle relative to a vertical direction. The chamber further includes an inlet and a first outlet. The surface heats a liquid in the chamber, causing the liquid to boil. In operation, bubbles rise from the surface and are forced in a horizontal direction by the baffle disposed in the chamber.

  14. 78 FR 46315 - Foreign-Trade Zone (FTZ) 247-Erie, Pennsylvania, Notification of Proposed Production Activity, GE...

    Science.gov (United States)

    2013-07-31

    ...; refrigerators; fuel heaters; heat exchangers; exhaust gas coolers; warming ovens; baffles; bonnet lube oil...; motorized wheels; AC drills; alternators; armatures; bus rings; armature coils; coils; commutators; dynamic... assemblies; weldments; barrier assemblies; coil assemblies; door assemblies; duct assemblies; dynamic brake...

  15. UV water disinfector

    Science.gov (United States)

    Gadgil, A.; Garud, V.

    1998-07-14

    A UV disinfector with a gravity driven feed water delivery system and an air-suspended bare UV lamp are disclosed. The disinfector is hydrodynamically optimized with a laminerizing, perforated baffle wall, beveled treatment chamber, and outlet weir. 7 figs.

  16. Combined bypass for fishes and drifting materials in hydropower plants; Kombinierter Fisch- und Treibgutableiter fuer Wasserkraftanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Gluch, A. [Landesbetrieb fuer Hochwasserschutz und Wasserwirtschaft Sachsen-Anhalt, Halle (Germany)

    2007-07-01

    Combined filter for fishes and drift goods (principle Gluch) are in operation since 2006. A baffle wall assembly being inclined by 45 against the streaming along the turbine, as well as a horizontal staff rake in vertical direction to the baffle wall assemble conduct fishes and drift goods into a bypass pit. Permanent openings in the washing shutter guarantee a harmless removal of sole oriented fishes and sediments as well as free water fishes and drift goods.

  17. Experimental Study of Blast Mitigation in a Water Mist

    Science.gov (United States)

    2006-11-01

    that was either in air or submerged in a water container (surrounded by rubber balloons filled with water). The presence of the rubber balloons was...psi (350 and 700 KPa). Endevco gauges employ a silicon diaphragm onto which a four-arm Wheatstone bridge has been diffused. The gauges were mounted...frequency vibration. A baffle plate is shown in Fig. 2. The baffle plate is a machined aluminium knife-edged disc, which is fixed to the top of a gauge

  18. Verifying mixing in dilution tunnels How to ensure cookstove emissions samples are unbiased

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Daniel L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rapp, Vi H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Caubel, Julien J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chen, Sharon S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gadgil, Ashok J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-12-15

    A well-mixed diluted sample is essential for unbiased measurement of cookstove emissions. Most cookstove testing labs employ a dilution tunnel, also referred to as a “duct,” to mix clean dilution air with cookstove emissions before sampling. It is important that the emissions be well-mixed and unbiased at the sampling port so that instruments can take representative samples of the emission plume. Some groups have employed mixing baffles to ensure the gaseous and aerosol emissions from cookstoves are well-mixed before reaching the sampling location [2, 4]. The goal of these baffles is to to dilute and mix the emissions stream with the room air entering the fume hood by creating a local zone of high turbulence. However, potential drawbacks of mixing baffles include increased flow resistance (larger blowers needed for the same exhaust flow), nuisance cleaning of baffles as soot collects, and, importantly, the potential for loss of PM2.5 particles on the baffles themselves, thus biasing results. A cookstove emission monitoring system with baffles will collect particles faster than the duct’s walls alone. This is mostly driven by the available surface area for deposition by processes of Brownian diffusion (through the boundary layer) and turbophoresis (i.e. impaction). The greater the surface area available for diffusive and advection-driven deposition to occur, the greater the particle loss will be at the sampling port. As a layer of larger particle “fuzz” builds on the mixing baffles, even greater PM2.5 loss could occur. The micro structure of the deposited aerosol will lead to increased rates of particle loss by interception and a tendency for smaller particles to deposit due to impaction on small features of the micro structure. If the flow stream could be well-mixed without the need for baffles, these drawbacks could be avoided and the cookstove emissions sampling system would be more robust.

  19. A New Method Solving Contact/Detach Problem in Fluid and Structure Interaction Simulation with Application in Modeling of a Safety Valve

    Directory of Open Access Journals (Sweden)

    Zheng Guo

    2010-01-01

    Full Text Available A new virtual baffle methodology is implemented to solve contact/detach problem which is often encountered in fluid and structure interaction simulations while using dynamic grids technique. The algorithm is based on tetrahedral unstructured grid, and a zero thickness baffle face is generated between actually contacted two objects. In computation process, this baffle face is divided into two parts representing convective and blocked area, respectively; the area of each part is calculated according to the actual displacement between the two objects. Convective part in a baffle face is treated as inner interface between cells, and on blocked part wall boundary condition is applied; so convective and blocking effect can be achieved on a single baffle face. This methodology can simulate real detaching process starting from contact, that is, zero displacement, while it has no restriction to minimum grid cell size. The methodology is then applied in modeling of a complicated safety valve opening process, involving multidisciplinary fluid and structure interaction and dynamic grids. The results agree well with experimental data, which proves that the virtual baffle method is successful.

  20. Optimization of flow control devices in a ten-strand billet caster tundish

    Directory of Open Access Journals (Sweden)

    Shu-guo Zheng

    2016-11-01

    Full Text Available The physical model of a ten-strand billet caster tundish was established to study the effects of various flow control devices on the melt flow. Before and after the optimization of the melt flow, the inclusion removal in the tundish was evaluated by plant trials. The physical modeling results show that when combined with a baffle, the turbulence inhibitor, instead of the impact pad, can significantly improve the melt flow. A turbulence inhibitor with a longer length of inner cavity and without an extending lip at the top of the sidewall seems to be efficient in the improvement of the melt flow. Various types and designs of baffles all influence the flow characteristics significantly. The “V” type baffles are better than the straight baffles for flow control. The “V” type baffle with four inclined holes at the sidewall away from the stopper rods is better in melt flow control than the one with one inclined hole at each sidewall. The combination of a well-designed turbulence inhibitor and an appropriate baffle shows high efficiency on improving the melt flow and an optimal proposal was presented. Plant trials indicate that, compared with the original tundish configuration in prototype, the inclusions reduce by 42% and the inclusion distribution of individual strands is more similar with the optimal one. The optimal tundish configuration effectively improves the melt flow in the ten-strand billet caster tundish.

  1. Development of response models for the Earth Radiation Budget Experiment (ERBE) sensors. Part 3: ERBE scanner measurement accuracy analysis due to reduced housekeeping data

    Science.gov (United States)

    Choi, Sang H.; Chrisman, Dan A., Jr.; Halyo, Nesim

    1987-01-01

    The accuracy of scanner measurements was evaluated when the sampling frequency of sensor housekeeping (HK) data was reduced from once every scan to once every eight scans. The resulting increase in uncertainty was greatest for sources with rapid or extreme temperature changes. This analysis focused on the mirror attenuator mosaic (MAM) baffle and plate and scanner radiometer baffle due to their relatively high temperature changes during solar calibrations. Since only solar simulator data were available, the solar temperatures were approximated on these components and the radiative and thermal gradients in the MAM baffle due to reflected sunlight. Of the two cases considered for the MAM plate and baffle temperatures, one uses temperatures obtained from the ground calibration. The other attempt uses temperatures computed from the MAM baffle model. This analysis shows that the heat input variations due largely to the solar radiance and irradiance during a scan cycle are small. It also demonstrates that reasonable intervals longer than the current HK data acquisition interval should not significantly affect the estimation of a radiation field in the sensor field-of-view.

  2. An investigation of inconsistent projections and artefacts in multi-pinhole SPECT with axially aligned pinholes

    International Nuclear Information System (INIS)

    Kench, P L; Meikle, S R; Lin, J; Gregoire, M C

    2011-01-01

    Multiple pinholes are advantageous for maximizing the use of the available field of view (FOV) of compact small animal single photon emission computed tomography (SPECT) detectors. However, when the pinholes are aligned axially to optimize imaging of extended objects, such as rodents, multiplexing of the pinhole projections can give rise to inconsistent data which leads to 'ghost point' artefacts in the reconstructed volume. A novel four pinhole collimator with a baffle was designed and implemented to eliminate these inconsistent projections. Simulation and physical phantom studies were performed to investigate artefacts from axially aligned pinholes and the efficacy of the baffle in removing inconsistent data and, thus, reducing reconstruction artefacts. SPECT was performed using a Defrise phantom to investigate the impact of collimator design on FOV utilization and axial blurring effects. Multiple pinhole SPECT acquired with a baffle had fewer artefacts and improved quantitative accuracy when compared to SPECT acquired without a baffle. The use of four pinholes positioned in a square maximized the available FOV, increased acquisition sensitivity and reduced axial blurring effects. These findings support the use of a baffle to eliminate inconsistent projection data arising from axially aligned pinholes and improve small animal SPECT reconstructions.

  3. A dynamic ultrasonic emitter inspired by horseshoe bat noseleaves.

    Science.gov (United States)

    Fu, Yanqing; Caspers, Philip; Müller, Rolf

    2016-04-29

    The emission of biosonar pulses in horseshoe bats (family Rhinolophidae) differs from technical sonar in that it has dynamic features at the interface to the free field. When the horseshoe bats emit their biosonar pulses through the nostrils, the walls of a horn-shaped baffle (anterior leaf) are in motion while diffracting the outgoing ultrasonic wave packets. Here, biomimetic reproductions of the dynamic emission shapes of horseshoe bats have been studied for their ability to impose time-variant signatures onto the outgoing pulses. It was found that an elliptical sound outlet with rotating baffles that were attached along the direction of the major axis can be well suited for this purpose. Most importantly, concave baffle shapes were found to produce strongly time-dependent devices characteristics that could reach a root-mean-square-difference between beampatterns of almost 6 dB within a rotation angle of 10°. In contrast to this, a straight baffle shape needs to be rotated over 60° for a similar result. When continuously rotated in synchrony with the emitted pulses, the concave biomimetic baffles produced time-variant device characteristics that depended jointly on direction, frequency, and time. Since such device properties are so easily produced, it appears well worthwhile to explore their use in engineering.

  4. Seasonal variations of microbial community in a full scale oil field produced water treatment plant

    Directory of Open Access Journals (Sweden)

    Q. Xie

    2016-01-01

    Full Text Available This study investigated the microbial community in a full scale anaerobic baffled reactor and sequencing batch reactor system for oil-produced water treatment in summer and winter. The community structures of fungi and bacteria were analyzed through polymerase chain reaction–denaturing gradient gel electrophoresis and Illumina high-throughput sequencing, respectively. Chemical oxygen demand effluent concentration achieved lower than 50 mg/L level after the system in both summer and winter, however, chemical oxygen demand removal rates after anaerobic baffled reactor treatment system were significant higher in summer than that in winter, which conformed to the microbial community diversity. Saccharomycotina, Fusarium, and Aspergillus were detected in both anaerobic baffled reactor and sequencing batch reactor during summer and winter. The fungal communities in anaerobic baffled reactor and sequencing batch reactor were shaped by seasons and treatment units, while there was no correlation between abundance of fungi and chemical oxygen demand removal rates. Compared to summer, the total amount of the dominant hydrocarbon degrading bacteria decreased by 10.2% in anaerobic baffled reactor, resulting in only around 23% of chemical oxygen demand was removed in winter. Although microbial community significantly varied in the three parallel sulfide reducing bacteria, the performance of these bioreactors had no significant difference between summer and winter.

  5. Monolithic fuel injector and related manufacturing method

    Science.gov (United States)

    Ziminsky, Willy Steve [Greenville, SC; Johnson, Thomas Edward [Greenville, SC; Lacy, Benjamin [Greenville, SC; York, William David [Greenville, SC; Stevenson, Christian Xavier [Greenville, SC

    2012-05-22

    A monolithic fuel injection head for a fuel nozzle includes a substantially hollow vesicle body formed with an upstream end face, a downstream end face and a peripheral wall extending therebetween, an internal baffle plate extending radially outwardly from a downstream end of the bore, terminating short of the peripheral wall, thereby defining upstream and downstream fuel plenums in the vesicle body, in fluid communication by way of a radial gap between the baffle plate and the peripheral wall. A plurality of integral pre-mix tubes extend axially through the upstream and downstream fuel plenums in the vesicle body and through the baffle plate, with at least one fuel injection hole extending between each of the pre-mix tubes and the upstream fuel plenum, thereby enabling fuel in the upstream plenum to be injected into the plurality of pre-mix tubes. The fuel injection head is formed by direct metal laser sintering.

  6. Numerical Modeling of the Fluid Flow in Continuous Casting Tundish with Different Control Devices

    Directory of Open Access Journals (Sweden)

    Zhu He

    2013-01-01

    Full Text Available Numerical simulations were conducted to study the melt flow under the influence of control devices in a T-type two-strand bloom caster tundish via the open source Computational Fluid Dynamics software OpenFOAM. Three different cases were studied: a bare tundish, a tundish with two pairs of baffles, and a tundish equipped with a turbulence inhibitor and a pair of baffles. Turbulence inhibitor and baffles arrangement showed an improvement of the fluid flow characteristics, yielding lower values of dead volume and higher values of plug flow. With a turbulence inhibitor, the velocity of metal which flows directly toward the tundish floor is smaller and the turbulence kinetic energy of the melt top surface is lower than the other two arrangements.

  7. Engineering, installation, testing, and initial operation of the DIII-D Advanced Divertor

    International Nuclear Information System (INIS)

    Andersen, P.M.; Baxi, C.B.; Reis, E.E.; Schaffer, M.J.; Smith, J.P.

    1990-09-01

    The Advanced Divertor (AD) for General Atomics tokamak, DIII-D, was installed in the summer of 1990. The AD has enabled two classes of physics experiments to be run: divertor biasing and divertor baffling. Both are new experiments for DIII-D. The AD has two principal components: (1) a continuous ring electrode; and (2) a toroidally symmetric baffle. The tokamak can be run in bias baffle or standard DIII-D divertor modes by accurate positioning of the outer divertor strike point through the use of the DIII-D control system. The paper covers design, analysis, fabrication, installation, instrumentation, testing, initial operation, and future plans for the Advanced Divertor from an engineering viewpoint. 2 refs., 5 figs

  8. Single bi-temperature thermal storage tank for application in solar thermal plant

    Energy Technology Data Exchange (ETDEWEB)

    Litwin, Robert Zachary; Wait, David; Lancet, Robert T.

    2017-05-23

    Thermocline storage tanks for solar power systems are disclosed. A thermocline region is provided between hot and cold storage regions of a fluid within the storage tank cavity. One example storage tank includes spaced apart baffles fixed relative to the tank and arranged within the thermocline region to substantially physically separate the cavity into hot and cold storage regions. In another example, a flexible baffle separated the hot and cold storage regions and deflects as the thermocline region shifts to accommodate changing hot and cold volumes. In yet another example, a controller is configured to move a baffle within the thermocline region in response to flow rates from hot and cold pumps, which are used to pump the fluid.

  9. Simulation and measurement of the suppression of radon induced background in the KATRIN experiment

    Science.gov (United States)

    Wolf, J.; Harms, F.

    2018-01-01

    Short-lived radon isotopes, such as 219Rn or 220Rn, are a serious source of background for the measurement of the neu-trino mass with the KATRIN experiment. Most of the radon emanates from the main vacuum pumps of the KATRIN Main Spec-trometer, which consist of 2000 m of Non-Evaporable Getter (NEG) strips. This paper describes a method to suppress the radon rate with liquid-nitrogen-cooled baffles in front of the NEG-pumps in the ultra-high vacuum chamber and compares simulations with measured data. The effectiveness of the method depends both on the half-life of the radon isotopes, and on the temperature of the cryogenic baffles, which affects their sojourn time on the cold surface. The measurements with the Main Spectrometer showed that the radon suppression with cold baffles works sufficiently well, so that the remaining background is no longer dominated by radon decays.

  10. Fluid-dynamic characterization of real-scale raceway reactors for microalgae production

    International Nuclear Information System (INIS)

    Mendoza, J.L.; Granados, M.R.; Godos, I. de; Acién, F.G.; Molina, E.; Banks, C.; Heaven, S.

    2013-01-01

    The fluid dynamic characterization of a 100 m length × 1 m wide channel raceway photobioreactor was carried out. The effects of water depth, liquid velocity and the presence, or absence, of sump baffles to improve the CO 2 supply transfer were considered in relation to on the power consumption, residence time and mixing in the reactor was studied. When operated at a depth of 20 cm, the power consumption was between 1.5 and 8.4 W m −3 depending on the forward velocity, with higher values occurring when the baffle was in place. Residence times and the degree of mixing at each section of the raceway (paddlewheel, bends, channels and sump) were measured experimentally. Mixing occurred mainly in the sump, paddlewheel and bends, with a maximum dispersion coefficient of 0.07 m 2 s −1 . These sections, however, only contributed a small fraction to the total volume of the raceway. Bodenstein numbers from 200 to 540 for the channel sections indicated plug-flow characteristics. Mixing times ranged from 1.4 to 6 h, with the presence of the baffle greatly increasing these times despite higher specific power consumption. A total of 15–20 circuits of the raceway were needed to achieve complete mixing without the baffle, compared to 30–40 cycles with the baffle. Vertical mixing was very poor whereas axial mixing was similar to that achieved in closed photobioreactors. The methodologies applied were shown to be useful in determining the fluid dynamics of a raceway photobioreactor. Equations useful in simulating the power consumption as a function of the design and operation parameters have been validated. -- Highlights: •Power consumption due to accessories can limit the use of raceway reactors for energy purposes. •Use of baffle to enhance mass transfer dramatically increases the power consumption in this type of photobioreactors. •High mixing time, in the order of hours, in raceway reactors limits the operation mode of these systems

  11. Reflective and refractive optical materials for earth and space applications; Proceedings of the Meeting, Orlando, FL, Apr. 4, 5, 1991

    Science.gov (United States)

    Riedl, Max J.; Hale, Robert R.; Parsonage, Thomas B.

    The present conference discusses beryllium mirror design and fabrication, production of aspheric beryllium optical surfaces by HIP consolidation, the control of thermally induced porosity for the fabrication of beryllium optics, fine-grained beryllium optical coatings, light-absorbing beryllium baffle materials, and advanced broadband baffle materials. Also discussed are radiation-resistant optical glasses, a catalog of IR and cryooptical properties of selected materials, durable metal-dielectric mirror coatings, the optical stability of diffuse reflectance materials, and optical filters for space applications.

  12. System and process for biomass treatment

    Science.gov (United States)

    Dunson, Jr., James B; Tucker, III, Melvin P; Elander, Richard T; Lyons, Robert C

    2013-08-20

    A system including an apparatus is presented for treatment of biomass that allows successful biomass treatment at a high solids dry weight of biomass in the biomass mixture. The design of the system provides extensive distribution of a reactant by spreading the reactant over the biomass as the reactant is introduced through an injection lance, while the biomass is rotated using baffles. The apparatus system to provide extensive assimilation of the reactant into biomass using baffles to lift and drop the biomass, as well as attrition media which fall onto the biomass, to enhance the treatment process.

  13. Tritium distribution on plasma facing graphite tiles of JT-60U

    International Nuclear Information System (INIS)

    Tanabe, T.; Sugiyama, K.; Masaki, K.; Gotoh, Y.; Tobita, K.; Miya, N.

    2003-01-01

    Tritium distributions on the graphite divertor tiles, the dome units and the baffle plates of JT-60U were successfully measured. Poloidally, the highest tritium level was found at the dome top tiles and the outer baffle plates, where the plasma did not hit directly. On the other hand, although the toroidal tritium profiles on each tiles appeared uniform, detailed profiles in full toroidal direction clearly showed a periodic variation corresponding to the position of the magnetic field coils, indicating the ripple loss of high energy tritons as suggested by the OFMC code. Finally, the temperature increase owing to the plasma heat load was found to release the once retained tritium. (author)

  14. Combustion heater for oil shale

    Science.gov (United States)

    Mallon, Richard G.; Walton, Otis R.; Lewis, Arthur E.; Braun, Robert L.

    1985-01-01

    A combustion heater for oil shale heats particles of spent oil shale containing unburned char by burning the char. A delayed fall is produced by flowing the shale particles down through a stack of downwardly sloped overlapping baffles alternately extending from opposite sides of a vertical column. The delayed fall and flow reversal occurring in passing from each baffle to the next increase the residence time and increase the contact of the oil shale particles with combustion supporting gas flowed across the column to heat the shale to about 650.degree.-700.degree. C. for use as a process heat source.

  15. Heat Exchanger With Internal Pin Elements

    Science.gov (United States)

    Gerstmann, Joseph; Hannon, Charles L.

    2004-01-13

    A heat exchanger/heater comprising a tubular member having a fluid inlet end, a fluid outlet end and plurality of pins secured to the interior wall of the tube. Various embodiments additionally comprise a blocking member disposed concentrically inside the pins, such as a core plug or a baffle array. Also disclosed is a vapor generator employing an internally pinned tube, and a fluid-heater/heat-exchanger utilizing an outer jacket tube and fluid-side baffle elements, as well as methods for heating a fluid using an internally pinned tube.

  16. Space-dependent core/reflector boundary conditions generated by the boundary element method for pressurized water reactors

    International Nuclear Information System (INIS)

    Itagaki, M.; Brebbia, C.A.

    1991-01-01

    This paper reports on the boundary element method used to generate energy-dependent matrix-type boundary conditions along core/reflector interfaces and along baffle-plate surfaces of pressurized water reactors. This method enables one to deal with all types of boundary geometries including convex and concave corners. The method is applicable to neutron diffusion problems with more than two energy groups and also can be used to model a reflector with or without a baffle plate. Excellent eigenvalue and flux shape results can be obtained when the boundary conditions generated by this technique are coupled with core-only finite difference calculations

  17. Three-dimensional analysis of liquid oxygen sloshing in Space Shuttle external tank

    Science.gov (United States)

    Kannapel, M. D.; Przekwas, A. J.; Singhal, A. K.; Costes, N. C.

    1987-01-01

    A three-dimensional numerical simulation has been performed in order to investigate the hydrodynamics within the liquid oxygen tank of the Space Shuttle external tank after liftoff. The results indicate that the LOX surface undergoes very high vertical accelerations (up to 5 g) and that splashing almost certainly occurs. Although the number of slosh baffles is not found to affect the surface, it is noted that the number of baffles may affect the structural motion of the tank. Surface accelerations are similar to those observed in previous two-dimensional simulations.

  18. Deep simplicity chaos, complexity and the emergence of life

    CERN Document Server

    Gribbin, John

    2005-01-01

    The world around us can be a complex, confusing place. Earthquakes happen without warning, stock markets fluctuate, weather forecasters seldom seem to get it right - even other people continue to baffle us. How do we make sense of it all? This title illuminates the harmony underlying our existence.

  19. Free convection of Walter's fluid flow in a vertical double-passage ...

    African Journals Online (AJOL)

    Free convection of Walter's fluid flow in a vertical double-passage wavy channel with heat source. ... Numerical results are presented graphically for the distribution of velocity and temperature fields for varying physical parameters such as baffle position, Grashof number, wall temperature ratio, viscoelastic parameter and ...

  20. Time-domain Simulations of the Acoustic Streaming Produced by a Propagating Wave Radiated by a Circular Piston

    DEFF Research Database (Denmark)

    Santillan, Arturo Orozco

    2013-01-01

    Results of numerical simulations of the sound field produced by a circular piston in a rigid baffled are presented. The aim was to calculate the acoustic streaming and the flow of mass generated by the sound field. For this purpose, the classical finite-difference time-domain method was implemented...

  1. Alveolar targeting of aerosol pentamidine. Toward a rational delivery system

    Energy Technology Data Exchange (ETDEWEB)

    Simonds, A.K.; Newman, S.P.; Johnson, M.A.; Talaee, N.; Lee, C.A.; Clarke, S.W. (Royal Free Hospital, London (England))

    1990-04-01

    Nebulizer systems that deposit a high proportion of aerosolized pentamidine on large airways are likely to be associated with marked adverse side effects, which may lead to premature cessation of treatment. We have measured alveolar deposition and large airway-related side effects (e.g., cough, breathlessness, and effect on pulmonary function) after aerosolization of 150 mg pentamidine isethionate labeled with {sup 99m}Tc-Sn-colloid. Nine patients with AIDS were studied using three nebulizer systems producing different droplet size profiles: the Acorn System 22, Respirgard II, and Respirgard II with the inspiratory baffle removed. Alveolar deposition was greatest and side effects least with the nebulizer producing the smallest droplet size profile (Respirgard II), whereas large airway-related side effects were prominent and alveolar deposition lowest with the nebulizer producing the largest droplet size (Acorn System 22). Values for alveolar deposition and adverse airway effects were intermediate using the Respirgard with inspiratory baffle removed, thus indicating the importance of the baffle valve in determining droplet size. Addition of a similar baffle valve to the Acorn System 22 produced a marked improvement in droplet size profile. Selection of a nebulizer that produces an optimal droplet size range offers the advantage of enhancing alveolar targeting of aerosolized pentamidine while reducing large airway-related side effects.

  2. Whose Confession? Which Tradition? (A Preliminary Critique of Penny Thompson, 2004)

    Science.gov (United States)

    Doble, Peter

    2005-01-01

    What does Penny Thompson really want? Reading her article in "BJRE" 26 (1) proved a baffling experience: it clearly wanted to say something, and to say it passionately, yet signally failed to do so. It fails largely because it lacks an argument; there seems also to be conceptual muddle at its heart. A fuller critique will need to attend…

  3. Experimental and numerical investigations of flow through free ...

    African Journals Online (AJOL)

    2010-06-05

    Jun 5, 2010 ... tional fluid dynamics (CFD) Fluent package (ANSYS, 2006) to numerically simulate the hydraulic performance and flow struc- ture throughout the double baffled gate distributors. The final stage involved the analysis of the experimental and simulated data and the production of a user-friendly spreadsheet to ...

  4. Absolute quantum yield measurements for the formation of oxygen ...

    Indian Academy of Sciences (India)

    Unknown

    For this purpose, narrow band VUV laser light tunable around the H atom Lyman α transition ... carefully separated from the fundamental laser light by a lens monochromator followed by a light baffle system. ..... carried out by Hui and Rice for SO2 at room-temperature under bulb conditions.20 In the latter work, for the 222⋅4 ...

  5. Large eddy simulations of flow instabilities in a stirred tank generate by a Rushton turbine

    DEFF Research Database (Denmark)

    Fan, Jianhua; Wang, Yundong; Fei, Weiyang

    2007-01-01

    The aim of this paper is to investigate the flow instabilities in a baffled, stirred tank generated by a single Rushton turbine by means of large eddy simulation (LES) and simulation using the k-ε turbulent model. A sliding mesh method was used for the coupling between the rotating and the statio...

  6. Effects of temperature on chirp rates of tree crickets (Orthoptera ...

    African Journals Online (AJOL)

    1991-10-02

    Oct 2, 1991 ... The relationship between temperature and chirp rate is described for three African tree crickets, Oecanthus capensis, 0. karschi and O. ... Finally, the animal should sing from an elevated position, such as a tree, shrub or ... incorrectly referred to as O. burmeisteri, is known for its baffle-making behaviour.

  7. Impact of arcing on carbon and tungsten. From the observations in JT-60U, LHD, and NAGDIS-II

    International Nuclear Information System (INIS)

    Kajita, Shin; Fukumoto, Masakatsu; Nakano, Tomohide; Tokitani, Masayuki; Masuzaki, Suguru; Ohno, Noriyasu; Takamura, Shuichi; Yoshida, Naoaki; Ueda, Yoshio

    2012-11-01

    This paper assesses the impact of arcing in fusion devices based on the observations in JT-60U, LHD, and the linear divertor simulator NAGDIS-II. In NAGDIS-II, the demonstration experiments of arcing/unipolar arcing have been conducted by simulating the transient heat load using a pulsed laser; it was found that the arcing can be easily initiated on the helium irradiated nanostructured tungsten. By measuring the field emission current property from the helium irradiated tungsten surface, the initiation conditions are discussed. From the detailed analysis of JT-60U tiles, it is found that arcing phenomena occurred on carbon baffle plates. From the observation of the arc trails recorded on the baffle plate, the amount of the eroded materials is discussed. The arcing seemed to occur frequently on inner baffles rather than the outer baffles. From LHD, it is shown that the arcing can be initiated on nanostructured tungsten even without transient events. The erosion of tungsten by arcing will become an important issue in a fusion reactor, where helium fluence is significantly increased. (author)

  8. We Need a Genuinely Demand-Led Skills System

    Science.gov (United States)

    Hartley, Ralph

    2010-01-01

    Anyone coming to the skills sector for the first time will swiftly find a baffling array of government "initiatives" and quangos. These latter bodies invariably claim to represent employer need, increase the status of vocational education or deliver best practice (delete as appropriate). The result is that the skills system as it…

  9. Joseph M. Nyasani It is not only astronomers who have been ...

    African Journals Online (AJOL)

    about what lies beyond the planetary system and the extent of that reality in terms of the space it occupies. Philosophers have equally been baffled by this same question even though it may not be fair to draw a sharp distinction between philosophy and astronomy in certain material respects of inquiry. For, many classical or ...

  10. Effects of rearing density and raceway conformation on growth, food conversion, and survival of juvenile spring chinook salmon

    Science.gov (United States)

    Ewing, R.D.; Sheahan, J.E.; Lewis, M.A.; Palmisano, Aldo N.

    2000-01-01

    Four brood years of juvenile spring chinook salmon Oncorhynchus tshawytscha were reared in conventional and baffled raceways at various rearing densities and loads at Willamette Hatchery, Oregon. A period of rapid linear growth occurred from August to November, but there was little or no growth from November to March when the fish were released. Both fall and winter growth rates were inversely related to rearing density. Final weight and length were also inversely related to rearing density. No significant relationship between load and any growth variable was observed. Fish reared at lower densities in conventional raceways tended to develop bimodal length distributions in winter and early spring. Fish reared in conventional raceways showed significantly larger growth rates and final lengths and weights than those reared in baffled raceways. Food conversions and average delivery times for feed were significantly greater in baffled than in conventional raceways. No significant relationships were observed between either rearing density or load and condition factor, food conversion, or mortality. Mortality was not significantly different between the two raceway types. When fish were transported to seawater for further rearing, there were no significant relationships between mortality in seawater and rearing density or load, but fish reared in baffled raceways had significantly higher mortality than those reared in conventional raceways.

  11. Development and Testing of Active Groundwater Samplers

    DEFF Research Database (Denmark)

    Nilsson, Bertel; Jakobsen, Rasmus; Andersen, Lars Jørgen

    1995-01-01

    Baffle System (PBS). The methodology and design of the two systems is presented and the operational application is demonstrated by examples from full-scale field experiments. The methods are validated and their sensitivity to the well construction and the hydrogeological environment is assessed based...

  12. The Handicap Principle

    Indian Academy of Sciences (India)

    IAS Admin

    The Handicap Principle is an idea proposed by the husband and wife scientist team of Amotz and Avishag Zahavi from. Israel in the 1970's. It is among the most innovative ideas of the 20th century in the field of behavioural biology and attempts to explain several long-standing puzzles that have baffled naturalists since the ...

  13. A Stylistic Study on the Linguistic Deviations in E. E. Cummings' Poetry

    Science.gov (United States)

    Li, Xin; Shi, Mengchen

    2015-01-01

    Regarded as the pioneer of experimental poetry, E. E. Cummings' unconventional treatment of poetic language has reached an unprecedented acme, which has intrigued and baffled numerous scholars, researchers and readers alike. Nevertheless, the very existence of poetry, like other types of literary texts, demonstrates the significance and value of…

  14. Retrospective dosimetry (or self dosimetry): Application to French Nuclear Power Plants

    International Nuclear Information System (INIS)

    Lloret, R.

    1993-01-01

    In this text we give the dosimetry principle on irradiated materials such baffle screw, pressure vessel and control element cans. This measure, made by gammametry, is based on the steel activation and comparison with calculated measures by Actige code. 4 figs., 6 refs

  15. UVES abundances of stars in nearby dwarf spheroidal galaxies

    NARCIS (Netherlands)

    Tolstoy, E; Venn, K; Shetrone, M; Primas, F; Hill, [No Value; Kaufer, A; Szeifert, T

    2002-01-01

    It is a truth universally acknowledged, that a galaxy in possession of a good quantity of gas must want to form stars. It is the details of how and why that baffle us all. The simplest theories either would have this process a carefully self-regulated affair, or one that goes completely out of

  16. The will to excel

    Indian Academy of Sciences (India)

    Lawrence

    organism, and soon after developed a quick immunofluoroscent technique for the early diagnosis of JE in patients. This was a turn- ing point in my career. Several questions baffled me about the epidemiology of. JE. Delving into these questions led to the startling discovery that a JE viral infection during pregnancy could be ...

  17. Variation Theory: A Theory of Learning and a Useful Theoretical Framework for Chemical Education Research

    Science.gov (United States)

    Bussey, Thomas J.; Orgill, MaryKay; Crippen, Kent J.

    2013-01-01

    Instructors are constantly baffled by the fact that two students who are sitting in the same class, who have access to the same materials, can come to understand a particular chemistry concept differently. Variation theory offers a theoretical framework from which to explore possible variations in experience and the resulting differences in…

  18. Author Details

    African Journals Online (AJOL)

    Menni, Younes. Vol 33 (2016) - Articles A numerical study of momentum and forced convection heat transfer in a rectangular channel with wall-mounted waved baffles. Abstract PDF. ISSN: 2352-9717. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about ...

  19. Author Details

    African Journals Online (AJOL)

    Zidani, Chafika. Vol 33 (2016) - Articles A numerical study of momentum and forced convection heat transfer in a rectangular channel with wall-mounted waved baffles. Abstract PDF. ISSN: 2352-9717. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about ...

  20. You Can't Come to My Birthday Party! Conflict Resolution with Young Children.

    Science.gov (United States)

    Evans, Betsy

    Noting that many teachers and parents are baffled by the repetitiveness of young children's conflict and by their own reaction to it, this book describes how adults can help children find alternatives to hurtful words and fighting by settling differences through a six-step mediation process based on several basic adult-child interaction…

  1. Crystallization: Key thermodynamic, kinetic and hydrodynamic aspects

    Indian Academy of Sciences (India)

    understanding of the thermodynamic, kinetic and hydrodynamic aspects of the design methodologies are not yet well ...... The mixer design is finalized with mechanical design of the shaft, impeller blade thickness, baffle thickness and supports, ...... PhD-Thesis, Delft University of Technol- ogy, Delft. Dimonte J E, Szutowski H ...

  2. Mapping the geothermal potential of fault zones in the Belgium-Netherlands border region

    NARCIS (Netherlands)

    Loveless, S.; Pluymaekers, M.P.D.; Lagrou, D.; Boever, E. de; Doornenbal, H.; Laenen, B.

    2014-01-01

    Faults can determine the success or failure of low enthalpy geothermal projects. This is due to their capacity to behave as pathways or baffles to geothermal water (or both simultaneously) and their prevalence throughout the subsurface. Here we present an initial assessment of the possibility for

  3. RE-SONANCE--IFe-br-Ua-rY

    Indian Academy of Sciences (India)

    Be, has baffled scientists for generations. The phenomenon is today known as the Mpemba effect, after the Tanzanian schoolboy Erasto. Mpemba. In the 1960s, Mpemba became a laughing stock after telling his science teacher he could make ice-cream mixture freeze faster by warming it before putting it into the freezer.

  4. Effect of Fin Passage Length on Optimization of Cylinder Head Cooling Fins

    Science.gov (United States)

    Siegel, R.; Graham, R. W.

    1977-01-01

    The heat transfer performance of baffled cooling fins on cylinder heads of small, air-cooled, general-aviation aircraft engines was analyzed to determine the potential for improving cooling fin design. Flow baffles were assumed to be installed tightly against the fin end edges, an ideal baffle configuration for guiding all flow between the fins. A rectangular flow passage is thereby formed between each set of two adjacent fins, the fin base surface, and the baffle. These passages extend around each side of the cylinder head, and the cooling air absorbs heat as it flows within them. For each flow passage length, the analysis was concerned with optimizing fin spacing and thickness to achieve the best heat transfer for each fin width. Previous literature has been concerned mainly with maximizing the local fin conductance and has not considered the heating of the gas in the flow direction, which leads to higher wall temperatures at the fin passage exits. If the fins are close together, there is a large surface area, but the airflow is restricted.

  5. A numerical study of momentum and forced convection heat transfer ...

    African Journals Online (AJOL)

    A numerical study has been carried out to examine the momentum and turbulent forced-convection characteristics for airflow through a constant temperature- surfaced rectangular duct with top and lower wallmounted waved baffles.Air is the working fluid with the flow rate in terms of Reynolds numbers ranging from 5,000 to ...

  6. Free convection of Walter's fluid flow in a vertical double-passage ...

    African Journals Online (AJOL)

    user

    influence on the velocity, temperature, skin friction and rate of heat transfer. 2. Mathematical formulation. Case 1: Free convection of Walter's fluid in a vertical channel with baffle. Consider a steady two dimensional laminar free convection Walter's fluid flow in an open-ended vertical channel with one wavy wall and another ...

  7. A computational fluid dynamics model for designing heat exchangers based on natural convection

    NARCIS (Netherlands)

    Dirkse, M.H.; Loon, van W.K.P.; Walle, van der T.; Speetjens, S.L.; Bot, G.P.A.

    2006-01-01

    A computational fluid dynamics model was created for the design of a natural convection shell-and-tube heat exchanger with baffles. The flow regime proved to be turbulent and this was modelled using the k¿¿ turbulence model. The features of the complex geometry were simplified considerably resulting

  8. Water SA - Vol 44, No 1 (2018)

    African Journals Online (AJOL)

    The effect of anaerobic baffled reactor effluent on nitrogen and phosphorus leaching from four soils in a laboratory column experiment · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Goitom Adhanom, Jeffrey Hughes, Alfred Odindo, 1-12.

  9. The pre-trial procedures and principles of the International Criminal ...

    African Journals Online (AJOL)

    Following the heinous cruelties perpetuated by the Nazi regime during the World War II, the world was baffled by the expanse of brutality human beings could commit against one another. However, there was absence of a universal acceptable international criminal procedural structure to try perpetrators of the atrocities.

  10. Linear sloshing frequencies in the annular region of a circular ...

    Indian Academy of Sciences (India)

    Sloshing in any type of container may invite instability to it. If some part of the free liquid surface in the annular region of a specially designed circular cylindrical container is covered with an annular baffle, the natural frequencies and the response of the liquid in the container undergo a drastic change. A partly covered free ...

  11. Sethian Crowns, Sethian Martyrs? Jewish Apocalypses and Christian Martyrs in a Gnostic Literary Tradition

    DEFF Research Database (Denmark)

    Burns, Dylan Michael

    2014-01-01

    The predominant image of the crown is among the most baffling features of several, difficult Gnostic apocalypses, recensions of which we know to have been controversial in the school of the Neoplatonic philosopher Plotinus (ca. 263 c.e.). In these “Sethian” apocalypses, recovered from Nag Hammadi...

  12. Cracking the Rhythm Codes in the Music of the Lumko District ...

    African Journals Online (AJOL)

    The rhythm systems in traditional Xhosa music have long baffled musicologists. When the author began to work with African church music at Lumko Institute in the late 1970s he undertook to study the music of the local people, who are Thembu Xhosa. With the help of Andrew Tracey he set out to try to 'crack' the rhythmic ...

  13. A simulated test of physical starting and reactor physics on zero power facility of PWR

    International Nuclear Information System (INIS)

    Yao Zewu; Ji Huaxiang; Chen Zhicheng; Yao Zhiquan; Chen Chen; Li Yuwen

    1995-01-01

    The core neutron economics has been verified through experiments conducted at a zero power reactor with baffles of various thickness. A simulated test of physical starting of Qinshan PWR has been introduced. The feasibility and safety of the programme are verified. The research provides a valuable foundation for developing physical starting programme

  14. Simulator Sickness: Reaction to a Transformed Perceptual World. 2. Sourcebook and Suggested Readings

    Science.gov (United States)

    1985-03-20

    or to a far greater extent) in the simulator. In other cases, the terms car, air, camel , sea or motion sickness should continue to be employed. It is...engineer from the pilots’ visual input by ine have negative consequences. This taxonomy insertion of the baffle significantly (p(.(111 comuined with

  15. Removal of Algae in Stabilization Ponds Effluent using Moringa ...

    African Journals Online (AJOL)

    A number of studies have proved natural coagulants achieve high turbidity removal in water treatment. A pilot scale study was conducted to evaluate the effectiveness of natural coagulant (moringa oleifera) with respect to algae removal. Required effluent from stabilization ponds was diverted into the horizontal baffle ...

  16. continuous-flow depulping machine for treculia africana

    African Journals Online (AJOL)

    Administrator

    from where it falls under gravity into the de-pulping chamber for further processing. The combination of crank and separation ... laboratory scale model of the machine is constructed and tested. Preliminary results indicate that 69– .... is available commercially with the trade name. “vent net”. The baffles consist of gauge 20.

  17. Experimental study on a solar air heater with various perforated covers

    Indian Academy of Sciences (India)

    Raheleh Nowzari

    2017-08-08

    Aug 8, 2017 ... heater with the quarter-perforated cover was slightly higher than that of the one with the half-perforated cover for both single- ... At the same mass flow rate, the average efficiency of the double-pass air heater with normal cover was. 50.92%. ...... characteristics via baffle blocks in a proton exchange mem-.

  18. Experimental study of a novel hybrid constructed wetland for water reuse and its application in Southern China

    NARCIS (Netherlands)

    Zhai, J.; Xiao, H.W.; Kujawa, K.; He, Q.; Kerstens, S.M.

    2011-01-01

    A new type of hybrid constructed wetland (CW), consisting of both vertical-baffled flow wetland (VBFW) and horizontal subsurface flow wetland (HSFW), has been deployed in Southern China to naturally accelerate the removal of organic matter and nitrogen. The hybrid CW system is characterised by a

  19. Beryllium assessment and recommendation for application in ITER plasma facing components

    International Nuclear Information System (INIS)

    Barabash, V.; Tanaka, S.; Matera, R.

    1998-01-01

    The design status of the ITER Plasma Facing Components (PFC) is presented. The operational conditions of the armour material for the different components are summarized. Beryllium is the reference armour material for the Primary Wall, Baffle and Limiter and the back-up material for the Divertor Dome. The activities on the selection of the Be grades and the joining technologies are reviewed. (author)

  20. Download this PDF file

    African Journals Online (AJOL)

    persons respond to the messages garnered to the control of the disease. Until this mistaken assumption is addressed, it is argued that no serious headway shall be made in the control of this disease, which threatens the very fabric of the Malawi nation. Introduction. The most baffling thing about the impact of HIV/AIDS is that.

  1. Joseph M. Nyasani It is not only astronomers who have been ...

    African Journals Online (AJOL)

    THE UBICATION OF THE PHYSICAL UNIVERSE. Joseph M. Nyasani. It is not only astronomers who have been wondering about what lies beyond the planetary system and the extent of that reality in terms of the space it occupies. Philosophers have equally been baffled by this same question even though it may not be fair ...

  2. The influence and mechanism of influent pH on anaerobic co ...

    African Journals Online (AJOL)

    Two pilot-scale activated sludge systems consisting of an anaerobic baffled reactor (ABR) and an aerobic plug flow reactor (PFR) were operated with the aim of minimising excess sludge output of the activated sludge process through coupled alkaline hydrolysis and anaerobic digestion. Variations in the effluent of total ...

  3. The Riddle in the Front Row

    Science.gov (United States)

    Bauman, M. Garrett

    2008-01-01

    In this article, the author describes how he was baffled with one of his students' blatant display of nonconforming attitude. Keenan is a student most loathed by his classmates. He didn't give a damn if the other students liked him. He scratched his crotch as he walked, and his unshampooed hair resembled a ragged carpet swatch. When he sneezed…

  4. Numerical investigation of flow and heat transfer in a novel configuration multi-tubular fixed bed reactor for propylene to acrolein process

    Science.gov (United States)

    Jiang, Bin; Hao, Li; Zhang, Luhong; Sun, Yongli; Xiao, Xiaoming

    2015-01-01

    In the present contribution, a numerical study of fluid flow and heat transfer performance in a pilot-scale multi-tubular fixed bed reactor for propylene to acrolein oxidation reaction is presented using computational fluid dynamics (CFD) method. Firstly, a two-dimensional CFD model is developed to simulate flow behaviors, catalytic oxidation reaction, heat and mass transfer adopting porous medium model on tube side to achieve the temperature distribution and investigate the effect of operation parameters on hot spot temperature. Secondly, based on the conclusions of tube-side, a novel configuration multi-tubular fixed-bed reactor comprising 790 tubes design with disk-and-doughnut baffles is proposed by comparing with segmental baffles reactor and their performance of fluid flow and heat transfer is analyzed to ensure the uniformity condition using molten salt as heat carrier medium on shell-side by three-dimensional CFD method. The results reveal that comprehensive performance of the reactor with disk-and-doughnut baffles is better than that of with segmental baffles. Finally, the effects of operating conditions to control the hot spots are investigated. The results show that the flow velocity range about 0.65 m/s is applicable and the co-current cooling system flow direction is better than counter-current flow to control the hottest temperature.

  5. 49 CFR 178.320 - General requirements applicable to all DOT specification cargo tank motor vehicles.

    Science.gov (United States)

    2010-10-01

    ... MATERIALS REGULATIONS SPECIFICATIONS FOR PACKAGINGS Specifications for Containers for Motor Vehicle... lading retention or containment function and provides no structural support to the cargo tank. Baffle.... Cargo tank means a bulk packaging that: (1) Is a tank intended primarily for the carriage of liquids...

  6. FLOW REGIMES, GAS HOLD-UP AND AXIAL GAS MIXING IN THE GAS-LIQUID MULTISTAGE AGITATED CONTACTOR

    NARCIS (Netherlands)

    BREMAN, BB; BEENACKERS, AACM; BOUMA, MJ

    Experimental data are reported on Row regimes, gas hold-up and axial gas mixing of a gas-liquid Multi-stage Agitated Contactor (MAC), consisting of nine compartments [height, H, over diameter, D = 1; D = 0.09 m) separated by horizontal baffles with an opening of 0.04 m and with one centrally

  7. Sadhana | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Linear sloshing frequencies in the annular region of a circular cylindrical container in the presence of a rigid baffle · N CHOUDHARY S N BORA · More Details Abstract Fulltext PDF. Sloshing in any type of container may invite instability to it. If some part of the free liquid surface in the annular region of a specially designed ...

  8. Sadhana | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Sloshing in any type of container may invite instability to it. If some part of the free liquid surface in the annular region of a specially designed circular cylindrical container is covered with an annular baffle, the natural frequencies and the response of the liquid in the container undergo a drastic change. A partly covered free ...

  9. Finite element simulation of internal flows with heat transfer using a ...

    Indian Academy of Sciences (India)

    Unknown

    heat exchanger is chosen as one of the problems for investigation. Flow past tube banks with a .... investigations have been undertaken by Ökajima (1982, 1990) to study the problem of vortex shedding behind ..... and doughnut baffled heat exchanger are analysed with the aid of turbulence models in high Reynolds number ...

  10. The Scarlet Ceremony: An Alex Blizard Story

    OpenAIRE

    Vlitos, PMJ

    2016-01-01

    A missing girl. A stolen dog. A frazzled detective. THE SCARLET CEREMONY sees sardonic London private eye Alex Blizard embark on his WEIRDEST, WILDEST adventure yet! Imagine THE WICKER MAN rewritten by Raymond Chandler and set in East London. Join our baffled hero as he attempts to unravel a case that is as BIZARRE as it is COMPELLING,

  11. Servicing NPPs in Japan, Korea and Taiwan

    International Nuclear Information System (INIS)

    Bohmann, W.; Poetz, F.

    1991-01-01

    More than 45 comparable orders (for equipment or services ) have been carried out in Japan, Korea and Taiwan by ABB Reaktor since 1982. Recently contracts to deliver inspection and repair equipment for the core baffle former bolts of Japanese NPPs, and in 1990, a contract to clean two steam generators in Korea, together with Pacific Nuclear Services, USA, were won. 2 figs

  12. Retention and distribution of Cu, Pb, Cr, and Zn in a full-scale hybrid constructed wetland receiving municipal sewage

    NARCIS (Netherlands)

    Xiao, H.W.; Zhang, S.L.; Zhai, J.; He, Q.; Mels, A.R.; Ning, K.J.; Liu, J.

    2013-01-01

    This study was conducted to investigate the retention and distribution of Cu, Pb, Cr, and Zn in a hybrid constructed wetland (CW) that consists of both vertical baffled flow wetlands (VBFWs) and horizontal subsurface flow wetlands (HSSFs) with unique flow regimes and oxygen distribution. The heavy

  13. Mixed convection of micropolar fluid in a vertical double-passage ...

    African Journals Online (AJOL)

    The solutions are evaluated numerically and shown graphically for the ratio of Grashof number to Reynolds number, material parameter and the baffle position on the velocity and microrotation velocity. It is found that the ratio of Grashof number to Reynolds number promotes the velocity whereas it suppresses the ...

  14. Integrated boiler, superheater, and decomposer for sulfuric acid decomposition

    Science.gov (United States)

    Moore, Robert [Edgewood, NM; Pickard, Paul S [Albuquerque, NM; Parma, Jr., Edward J.; Vernon, Milton E [Albuquerque, NM; Gelbard, Fred [Albuquerque, NM; Lenard, Roger X [Edgewood, NM

    2010-01-12

    A method and apparatus, constructed of ceramics and other corrosion resistant materials, for decomposing sulfuric acid into sulfur dioxide, oxygen and water using an integrated boiler, superheater, and decomposer unit comprising a bayonet-type, dual-tube, counter-flow heat exchanger with a catalytic insert and a central baffle to increase recuperation efficiency.

  15. Stray light field dependence for large astronomical space telescopes

    Science.gov (United States)

    Lightsey, Paul A.; Bowers, Charles W.

    2017-09-01

    Future large astronomical telescopes in space will have architectures that expose the optics to large angular extents of the sky. Options for reducing stray light coming from the sky range from enclosing the telescope in a tubular baffle to having an open telescope structure with a large sunshield to eliminate solar illumination. These two options are considered for an on-axis telescope design to explore stray light considerations. A tubular baffle design will limit the sky exposure to the solid angle of the cone in front of the telescope set by the aspect ratio of the baffle length to Primary Mirror (PM) diameter. Illumination from this portion of the sky will be limited to the PM and structures internal to the tubular baffle. Alternatively, an open structure design will allow a large portion of the sky to directly illuminate the PM and Secondary Mirror (SM) as well as illuminating sunshield and other structure surfaces which will reflect or scatter light onto the PM and SM. Portions of this illumination of the PM and SM will be scattered into the optical train as stray light. A Radiance Transfer Function (RTF) is calculated for the open architecture that determines the ratio of the stray light background radiance in the image contributed by a patch of sky having unit radiance. The full 4π steradian of sky is divided into a grid of patches, with the location of each patch defined in the telescope coordinate system. By rotating the celestial sky radiance maps into the telescope coordinate frame for a given pointing direction of the telescope, the RTF may be applied to the sky brightness and the results integrated to get the total stray light from the sky for that pointing direction. The RTF data generated for the open architecture may analyzed as a function of the expanding cone angle about the pointing direction. In this manner, the open architecture data may be used to directly compare to a tubular baffle design parameterized by allowed cone angle based on the

  16. Evacuation apparatus with cryogenic pump and trap assembly

    International Nuclear Information System (INIS)

    Mahl, G.

    1980-01-01

    An evacuation apparatus comprising a vessel defining a vacuum chamber therein, vacuumizing means communicating with an opening to said vacuum chamber for selectively drawing a vacuum therein comprising cryogenic pump means disposed closely adjacent to said opening and defined by substantial cryogenically cooled trap surfaces for freezing-out water vapor from air evacuated from said vacuum chamber, said opening being common to said vacuum chamber and to said cryogenic pump means, valve means for selectively opening or closing the opening to said vacuum chamber and movable from a first position within said cryogenic pump means closing said opening to a second position within said cryogenic pump means directly exposing said vacuum chamber to said cryogenic pump means, through said opening, baffle means disposed closely adjacent to the opening to said vacuum chamber for providing substantial open communication to said vacuum chamber and for substantially preventing ingress of contaminants into said vacuum chamber, said baffle means being positioned to provide an optically dense view of said opening when viewed from a downstream side of said baffle means, and a plurality of longitudinally spaced and cryogenically cooled fins mounted in nested relationship within said baffle means and disposed in out-of-contact relationship therewith, said fins being positioned to provide an optically dense view of the downstream side of said baffle means when viewed from said openings. The cryogenic pump is adapted for use in an evacuation apparatus comprising a housing defining an opening to a vacuum chamber, a plurality of metallic plates defining a first chamber therein communicating with said vacuum chamber through said opening and further defining a second chamber at least partially surrounding said first chamber and adapted to be at least partially filled with a cryogenic liqui.d

  17. Fluid elastic instability analysis of 1/6th experimental model of PFBR main vessel cooling circuit

    International Nuclear Information System (INIS)

    Jalaldeen, S.; Ravi, R.; Chellapandi, P.; Bhoje, S.B.

    1993-01-01

    In reactor assembly of Prototype Fast Breeder Reactor (PFBR), the main vessel (MV) temperature is kept below creep range i.e. less than 427 deg C by way of diverting a small fraction of core flow from the cold pool and sent through the passage between main vessel and an outer cylindrical baffle to cool the vessel. The sodium coning from this, is collected by another inner baffle and then returned to cold pool again. This system is termed as MV cooling circuit. The outer and inner baffles form feeding and restitution collectors respectively. The sodium from the feeding collector flows over the outer baffle and falls through a height of about 0.5 m before impacting on the free surface of sodium in the restitution collector. The fall of sodium may become a source of vibration of the baffles. Such vibrations have been already noted in case of SPX-I during its commissioning stage. For PFBR, the theoretical analysis was done to assess the fluid-elastic instability risks and stability charts were obtained. By this, it was concluded that the operating point (flow rate and fall height) lies within the stable zone. In order to confirm the above analysis results, a series of experiments were proposed. One preliminary experiment on 1/16 th model of MV cooling circuit has been completed. This model has also been analysed theoretically for the fluid- elastic instability, the theoretical analysis involves 2 stage computations. In the first stage, free vibration analysis with fluid structure interaction (FSI) effect for experimental model has been done using INCA (CASTEM 1985) code and all the mode shapes including sloshing are extracted. In the second stage the instability analysis is performed with the free vibration results from INCA. For the instability computations, a code WEIR has been written based on Aita's instability criteria [Aita.S. 1986

  18. CFD Modeling of Flow and Ion Exchange Kinetics in a Rotating Bed Reactor System

    DEFF Research Database (Denmark)

    Larsson, Hilde Kristina; Schjøtt Andersen, Patrick Alexander; Byström, Emil

    2017-01-01

    be achieved by making the baffles deeper. Two-phase simulations were performed, which managed to reproduce the deflection of the gas–liquid interface in an unbaffled system. A chemical reaction was implemented in the model, describing the ion-exchange phenomena in the porous material using four different......A rotating bed reactor (RBR) has been modeled using computational fluid dynamics (CFD). The flow pattern in the RBR was investigated and the flow through the porous material in it was quantified. A simplified geometry representing the more complex RBR geometry was introduced and the simplified...... model was able to reproduce the main characteristics of the flow. Alternating reactor shapes were investigated, and it was concluded that the use of baffles has a very large impact on the flows through the porous material. The simulations suggested, therefore, that even faster reaction rates could...

  19. A new star (sensor) is born

    Science.gov (United States)

    Leijtens, Johan; Vliegenthart, Willem; Lampridis, Dimitris; Vacanti, Giuseppe; Monna, Bert; Bechthum, Elbert; Hagenaars, Koen; van der Heide, Erik; Kruijff, Michiel; van Breukelen, Eddie; LeMair, Anita

    2017-11-01

    In the frame of the Dutch Prequalification for ESA Programs(PEP), as part of the efforts to design an integrated optical attitude control subsytem (IOPACS), a consortium of TNO and several SME's in the Netherlands have been working on a novel type of startracker called MABS (Multiple Aperture Baffled Startracker). The system comprises a single cast metal housing with four reflective optical telescopes which use only structural internal baffling. Inherent to the design are a very high stability and excellent co-alignment between the apertures, a significant decrease in system size and low recurring production cost. The concept is a radical change from more common multiple startracker setups. The presentation will concentrate on the validity of the concept, the predicted performance and benefits for space applications, the produced breadboard and measured performances as well as the costing aspects.

  20. A concept of external aerodynamic elements in improving the performance of natural smoke ventilation in wind conditions

    Science.gov (United States)

    Wegrzyński, Wojciech; Krajewski, Grzegorz; Kimbar, Grzegorz

    2018-01-01

    This paper is a proposal of a new device that may be used as a component of natural smoke ventilation systems - an external aerodynamic baffle used to limit the wind effect at the most adverse angle. Natural ventilation is not only affected by the external wind, but also dependent on the angle of wind attack. It has been proven, that at angles between 45° to 60° the performance of such device is the lowest. This is the reason why additional device is proposed - external baffle that could hypothetically increase the performance at chosen angles. The purpose of this paper is to explore this idea by numerical modelling of such external elements on a validated natural ventilator model, with use of ANSYS® Fluent® CFD model.

  1. HOMOGENEOUS NUCLEAR REACTOR

    Science.gov (United States)

    Hammond, R.P.; Busey, H.M.

    1959-02-17

    Nuclear reactors of the homogeneous liquid fuel type are discussed. The reactor is comprised of an elongated closed vessel, vertically oriented, having a critical region at the bottom, a lower chimney structure extending from the critical region vertically upwardly and surrounded by heat exchanger coils, to a baffle region above which is located an upper chimney structure containing a catalyst functioning to recombine radiolyticallydissociated moderator gages. In operation the liquid fuel circulates solely by convection from the critical region upwardly through the lower chimney and then downwardly through the heat exchanger to return to the critical region. The gases formed by radiolytic- dissociation of the moderator are carried upwardly with the circulating liquid fuel and past the baffle into the region of the upper chimney where they are recombined by the catalyst and condensed, thence returning through the heat exchanger to the critical region.

  2. Analysis of field coordination on heat exchanger shell side with different diameter tubes and holding structure

    International Nuclear Information System (INIS)

    Li Jing; Lu Minshan; Dong Qiwu

    2009-01-01

    In order to overcome the disadvantages of the rod-baffle heat exchanger, which achieves the high heat transfer efficiency only at high flow velocity, and which with non compact layout of tubes and is weak in the resistance of operation mode changes, this paper proposed two sizes of heat exchange tubes and holding and support structures to replace the traditional rod-baffle support unit, to increase the heat exchange coefficient on shell side and the heat exchange effectiveness. Three-dimensional numerical simulation was conducted on the shellside flow field and heat exchange field by the CFD software, and the calculation method was proposed for the included angle for the shellside velocity-temperature gradient fields of the vertical flow heat exchanger with complex structure. The quantitative relationship of the field coordination angle for the shellside velocity field and temperature gradient field was obtained and it is proved that the new structure is with better field coordination relation. (authors)

  3. Combustor and method for distributing fuel in the combustor

    Science.gov (United States)

    Uhm, Jong Ho; Ziminsky, Willy Steve; Johnson, Thomas Edward; York, William David

    2016-04-26

    A combustor includes a tube bundle that extends radially across at least a portion of the combustor. The tube bundle includes an upstream surface axially separated from a downstream surface. A plurality of tubes extends from the upstream surface through the downstream surface, and each tube provides fluid communication through the tube bundle. A baffle extends axially inside the tube bundle between adjacent tubes. A method for distributing fuel in a combustor includes flowing a fuel into a fuel plenum defined at least in part by an upstream surface, a downstream surface, a shroud, and a plurality of tubes that extend from the upstream surface to the downstream surface. The method further includes impinging the fuel against a baffle that extends axially inside the fuel plenum between adjacent tubes.

  4. Numerical and experimental study of a solid pellet feed continuous Czochralski growth process for silicon single crystals

    Science.gov (United States)

    Anselmo, A.; Prasad, V.; Koziol, J.; Gupta, K. P.

    1993-07-01

    A polysilicon pellets (≅1 mm diameter) feed continuous Czochralski (CCZ) growth process for silicon single crystals is proposed and investigated. Experiments in an industrial puller (14-18 inch diameter crucible) successfully demonstrate the feasibility of this process. The advantages of the proposed scheme are: a steady state growth process, a low aspect ratio melt, uniformity of heat addition and a growth apparatus with single crucible and no baffle(s). The addition of dopant with the solid charge will allow a better control of oxygen concentration leading to crystals of uniform properties and better quality. This paper presents theoretical results on melting of fully and partially immersed silicon spheres and numerical solutions on temperature and flow fields in low aspect ration melts with and without the addition of solid pellets. The theoretical and experimental results obtained thus far show a great promise for the proposed scheme.

  5. The optimization of a tubular condensation cryopump for pressures below 10/sup -13/ Torr (for intersecting storage rings for protons)

    CERN Document Server

    Benvenuti, C

    1974-01-01

    A cryopump design of tubular geometry is presented, which incorporates in its vacuum system only a very small fraction of ambient temperature walls. Furthermore, the total amount of the 300K radiation reaching the cold baffles is reduced by about two orders of magnitude. This has the double advantage that the baffles can be cooled at lower temperatures and can be allowed to be more 'transparent' to radiation and hence to molecules. The new model has been entirely optimised both for molecular and radiation transmission by a Monte Carlo method. It is designed to have a pumping speed of 3000 ls/sup -1/ for H/sub 2/ at the two entrances, an axial conductance providing a pressure drop across the pump of a factor of ten and a limit pressure in the 10/sup -14/ Torr range. (6 refs).

  6. Bioconversion reactor

    Science.gov (United States)

    McCarty, Perry L.; Bachmann, Andre

    1992-01-01

    A bioconversion reactor for the anaerobic fermentation of organic material. The bioconversion reactor comprises a shell enclosing a predetermined volume, an inlet port through which a liquid stream containing organic materials enters the shell, and an outlet port through which the stream exits the shell. A series of vertical and spaced-apart baffles are positioned within the shell to force the stream to flow under and over them as it passes from the inlet to the outlet port. The baffles present a barrier to the microorganisms within the shell causing them to rise and fall within the reactor but to move horizontally at a very slow rate. Treatment detention times of one day or less are possible.

  7. Scatter and contamination of a low-scatter mirror

    Science.gov (United States)

    McNeely, J. R.; McIntosh, M. B.; Akerman, M. A.

    1991-12-01

    The contamination of high-quality, space-borne optics by particles originating from baffle systems could significantly alter the performance of the optics. To assess this potential problem, the bidirectional reflectance distribution function (BRDF) of a low-scatter beryllium mirror was measured at the 10.6-micron wavelength with the mirror in the 'cleaned' state and after controlled contaminations with aluminum oxide powder up to 100 microns in size. The aluminum oxide powder was used to simulate particles which could be released from a typical baffle material. After contamination, the particle size distribution on the mirror surface was statistically sampled using a scanning electron microscope image analysis technique. The BRDF measurements of the contaminated mirror were compared to Mie scattering theory calculations for subwavelength, wavelength, and superwavelength particles sizes.

  8. Seismic design method of clamped-free thin cylindrical shells immersed in fluid

    International Nuclear Information System (INIS)

    Fukuyama, Mayumi; Nakagawa, Masaki; Yashiro, Takeshi; Toyoda, Yukihoro; Akiyama, Hiroshi

    2001-01-01

    We carried out excitation experiments on clamped-free thin cylindrical shells immersed in fluid that represented thermal baffles of a fast breeder reactor. At a certain excitation level, occurred external pressure buckling. We also observed that parametric vibration, which involved high-order circumferential vibration modes, occurred at a certain combination of excitation frequency and excitation level. Concerning seismic design of the thermal baffles, we, therefore, take not only the buckling but also the effect of the parametric vibration into consideration. We adopt buckling eigenvalue analyses to estimate buckling pressure and propose a formula to prevent the buckling. Further, we discuss important factors such as buckling strength reduction caused by initial shape imperfections and interaction between horizontal and vertical seismic response. Concerning the parametric vibration, a significant deformation of cylinders should be prevented. A practical method applying the dynamic stability theory is proposed to obtain the condition, under which the parametric vibration takes place

  9. Calculation of the performance of the INS iron-free π√2 spectrometer as a spectrograph

    International Nuclear Information System (INIS)

    Fujioka, M.; Hirasawa, M.; Kawakami, H.

    1983-02-01

    The performance of the INS iron-free π√2 beta-ray spectrometer of the current-loop type is calculated with a view of using it as a spectrograph, i.e., in a multichannel mode with a position-sensitive proportional counter. For the momentum resolution of R = 0.01 and 0.1 % the usable momentum range as a spectrograph ( + epsilon + 0 ) and the line shapes on the focal plane are calculated. The transmission of the baffle is 0.025 and 0.13 % of 4π and the expected gain of data-collection efficiency over the single-channel mode is 140 and 40 for R = 0.01 and 0.1%, respectively. An effective tilting of the focal plane due to the entrance baffle is discussed as well as the problems with arrangement and testing of the position detector. (author)

  10. Effect of Inlet Velocity on Heat Transfer Process in a Novel Photo-Fermentation Biohydrogen Production Bioreactor using Computational Fluid Dynamics Simulation

    OpenAIRE

    Zhiping Zhang; Qinglin Wu; Chuan Zhang; Yi Wang; Yameng Li; Quanguo Zhang

    2014-01-01

    Temperature is one of the most important parameters in biohydrogen production by way of photo-fermentation. Enzymatic hydrolysate of corncob powder was utilized as a substrate. Computational fluid dynamics (CFD) modeling was conducted to simulate the temperature distribution in an up-flow baffle photo-bioreactor (UBPB). Commercial software, GAMBIT, was utilized to mesh the photobioreactor geometry, while the software FLUENT was adopted to simulate the heat transfer in the photo-fermentation p...

  11. Titanium oxide fever

    International Nuclear Information System (INIS)

    De Jonge, D.; Visser, J.

    2012-01-01

    One measure to improve air quality is to apply photo-catalytic substances that capture NOx onto the road surface or onto baffle boards alongside the roads. The effect of titanium oxide containing clinkers with coating was discussed in the report 'Demonstration project of air-purifying pavement in Hengelo, The Netherlands' that was published in May 2011. This article examines the way in which the effectiveness of this study was determined. Can titanium oxide containing clinkers and coatings indeed capture NOx?. [nl

  12. Optical design of the STAR-X telescope

    Science.gov (United States)

    Saha, Timo T.; Zhang, William W.; McClelland, Ryan S.

    2017-08-01

    Top-level science objectives of the Survey and Time-domain Astrophysical Research eXplorer (STAR-X) include: investigations of most violent explosions in the universe, study of growth of black holes across cosmic time and mass scale, and measure how structure formation heats majority of baryons in the universe. To meet these objectives, the STAR-X telescope requires a field of view of about 1 square-degree, an angular resolution of 5 arc-seconds or better across large part of the field of view. The on-axis effective area at 1 keV should be about 2,000 cm2 . Payload cost and launch considerations limit the outer diameter, focal length, and mass to 1.3 meters, 5 meters, and 250 kilograms, respectively. Telescope design is based on a segmented meta-shell approach we have developed at Goddard Space Flight Center. The telescope mirror shells are divided into segments. Individual shells are nested inside each other to meet the effective area requirements in 0.5 - 6.0 keV range. We consider Wolter-Schwarzschild, and Modified-WolterSchwarzschild telescopes. These designs offer an excellent PSF over a large field of view. Nested shells are vulnerable to stray light problems. We have designed a multi-component baffle system to eliminate direct and single-reflection light paths inside the mirror assembly. Large numbers of internal and external baffles are required to prevent stray rays from reaching the focal plane. We have developed a simple ray-trace tool to determine the dimensions and locations of the baffles. In this paper, we present the results of our trade studies, baffle design studies, and optical performance analyses of the STAR-X telescope.

  13. Perspectives on Global and Regional Security and Implications of Nuclear and Space Technologies: U.S.-Brazil Strategic Dialogue, Phase 2 Report

    Science.gov (United States)

    2014-10-01

    normally would be able to be worked out.” Given its adherence to the democracy clause that forms part of the OAS, Mercosur , UNASUR charters, the U.S...Honduras, and countering threats to democracy in Venezuela . Brazil’s inaction left Washington “baffled,” according to one former senior defense official...the efficacy of regional institutions. U.S. participants suggested that Mercosur was a failure, while Brazilian participants disagreed, believing that

  14. Cognitive dimensions of predator responses to imperfect mimicry

    OpenAIRE

    Chittka, L; Osorio, D

    2007-01-01

    Many palatable animals, for example hoverflies, deter predators by mimicking well-defended insects such as wasps. However, for human observers, these flies often seem to be little better than caricatures of wasps—their visual appearance and behaviour are easily distinguishable from those which they are attempting to mimic. This imperfect mimicry baffles evolutionary biologists, because one might expect natural selection to do a more thorough job. Here we discuss two types of cognitive process...

  15. Effect of feed atomization and vessel configuration of fines formation and entrainment from fluidized-bed calciners

    International Nuclear Information System (INIS)

    Bonder, S.S.

    1978-11-01

    Fines and granules are produced during fluidized-bed calcination of liquid radioactive wastes. Fines are generated by attrition of larger bed particles and spray drying of atomized feed droplets. Some of the fines have sufficient residence time in the bed to provide seed particles for the particle growth; the remainder are elutriated from the bed or withdrawn with the product. Methods which were tested to reduce the generation and entrainment of fines during the calcination process are discussed. A pneumatic, flat-faced, feed atomizing nozzle has proven adequate for feed introduction, bed particle size control, and seed particle generation. Other pneumatic nozzle types (the extended divergent, long extended convergent, and short extended convergent) did not control bed particle size. Testing of a single-fluid pressure nozzle and the combination nozzle and cyclone fines return jet was discontinued before completion. However, no further testing to improve nozzle operating characteristics is presently justifiable, as the flat-faced nozzle has proven adequate. Limited tests confirmed that a cylindrical fluid bed with an expanded vapor space results in lower entrainment rates than a conventional cylindrical fluid bed. A reduction of the superficial gas velocity in the expanded vapor space by a factor of 3.2 reduced entrainment by a factor of 8. Double ''venetian blind'' baffles in the calciner vapor space were 20% more effective in suppressing fines entrainment than single ''venetian blind'' and fan baffles. Submerged baffles increased bed particle attrition and subsequent fines entrainment. The New Waste Calcining Facility will have a cylindrical calciner vessel with an expanded vapor space containing a double ''venetian blind'' baffle

  16. Applications of antireflection coatings in sonic crystal-based acoustic devices

    International Nuclear Information System (INIS)

    Wang Yun; Deng Ke; Xu Shengjun; Qiu Chunyin; Yang Hai; Liu Zhengyou

    2011-01-01

    The unwanted reflection seriously baffles the practical applications of sonic crystals, such as for various acoustic lenses designed by utilizing the in-band properties of sonic crystals. Herein we introduce the concept of the antireflection coating into the sonic crystal-based devices. The efficiency of such accessorial structures is demonstrated well by an originally high reflection system. Promising perspectives can be anticipated in extending the antireflection coating layers into more general acoustic applications through a flexible design process.

  17. Pumping Characteristics of the DIII-D Cryopump

    International Nuclear Information System (INIS)

    A.S. Bozek; C.B. Baxi; R.W. Callis; M.A. Mahdavi; R.C. O'Neill; E.E. Reis

    1999-01-01

    Beginning in 1992, the first of the DIII-D divertor baffles and cryocondensation pumps was installed. This open divertor configuration, located on the outermost floor of the DIII-D vessel, includes a cryopump with a predicted pumping speed of 50,000 ell/s excluding obstructions such as support hardware. Taking the pump structural and support characteristics into consideration, the corrected pumping speed for D 2 is 30,000 ell/s [1]. In 1996, the second divertor baffle and cryopump were installed. This closed divertor structure, located on the outermost ceiling of the DIII-D vessel, has a cryopump with a predicted pumping speed of 32,000 ell/s. In the fall of 1999, the third divertor baffle and cryopump will be installed. This divertor structure will be located on the 45 o angled corner on the innermost ceiling of the DIII-D vessel, known as the private flux region of the plasma configuration. With hardware supports factored into the pumping speed calculation, the private flux cryopump is expected to have a pumping speed of 15,000 ell/s. There was question regarding the effectiveness of the private flux cryopump due to the close proximity of the private flux baffle. This led to a conductance calculation study of the impact of rotating the cryopump aperture by 180 o to allow for greater particle and gas exhaust into the cryopump's helium panel. This study concluded that the cost and schedule impact of changing the private flux cryopump orientation and design did not warrant the possible 20% (3,000 ell/s) increase in pumping ability gained by rotating the cryopump aperture 180 o . The comparison of pumping speed of the first two cryocondensation pumps with the measured results will be presented as well as the calculation of the pumping speed for the private flux cryopump now being installed

  18. Molten metal reactor and method of forming hydrogen, carbon monoxide and carbon dioxide using the molten alkaline metal reactor

    Science.gov (United States)

    Bingham, Dennis N.; Klingler, Kerry M.; Turner, Terry D.; Wilding, Bruce M.

    2012-11-13

    A molten metal reactor for converting a carbon material and steam into a gas comprising hydrogen, carbon monoxide, and carbon dioxide is disclosed. The reactor includes an interior crucible having a portion contained within an exterior crucible. The interior crucible includes an inlet and an outlet; the outlet leads to the exterior crucible and may comprise a diffuser. The exterior crucible may contain a molten alkaline metal compound. Contained between the exterior crucible and the interior crucible is at least one baffle.

  19. Characterization of Decommissioned PWR Vessel Internals Material Samples: Tensile and SSRT Testing (Nonproprietary Version)

    International Nuclear Information System (INIS)

    Krug, M.; Shogan, R.

    2004-01-01

    Pressurized water reactor (PWR) cores operate under extreme environmental conditions due to coolant chemistry, operating temperature, and neutron exposure. Extending the life of PWRs requires detailed knowledge of the changes in mechanical and corrosion properties of the structural austenitic stainless steel components adjacent to the fuel (internals) subjected to such conditions. This project studied the effects of reactor service on the mechanical and corrosion properties of samples of baffle plate, former plate, and core barrel from a decommissioned PWR

  20. Heat transfer measurements with TOIRT method

    Science.gov (United States)

    Solnař, S.; Petera, K.; Dostál, M.; Jirout, T.

    Temperature Oscillation Infra-Red Thermography (TOIRT) method was used to measure heat transfer coefficients between a at surface and a confined impinging jet generated by an impeller in a difusor and baffled vessel. The TOIRT method is based on measuring a phase-lag between the oscillating heat flux applied to the heat transfer surface and the surface temperature response using a contactless infra-red camera. The phase lag is in a direct relationship with the heat transfer coefficient.

  1. Tearing at the Fabric - A Spiritual Journey Through Crisis and Trauma,

    Science.gov (United States)

    1995-05-01

    34 Life: These lyrics easily might depict baffled expectations, voiced frustrations and inner whispers up and down the pendulum’s arc of human existence...workers who "don’t understand" breakdown in trust false or distorted generalizations about others doubts about relationships changes in sexual activity...experiencing crises at home. He is having trouble with both of his teen -age children. Their behavior in school has deteriorated since changing

  2. Focusing on EFL reading theory and practice

    CERN Document Server

    Al-Mahrooqi, Rahma

    2014-01-01

    Reading, a complex and multi-faceted skill, is essential for life and academic success. While its mysteries still baffle first-language research, the nature of reading in a foreign language presents an even greater puzzle. However, given reading's importance for EFL students who study their specializations in English, and whose future employment may depend on their competence in it, researchers must continue to investigate foreign language reading and devise ways of improving students' capaci...

  3. The Global Epidemic of Childhood Obesity: Poverty, Urbanization, and the Nutrition Transition

    OpenAIRE

    Brody, Jennifer

    2002-01-01

    Childhood obesity is increasing worldwide at rates of epidemic proportion (1, 2). Previously a public health concern of only the modern, industrialized world, this problem now increasingly affects children and adolescents of poor, developing countries. This new and somewhat baffling phenomenon urgently begs the question: How is it that impoverished children around the world become obese? Recent studies suggest that rapid globalization and urbanization account for significant shifts in dietary...

  4. Remote systems requirements of the high-yield lithium injection fusion energy converter concept

    International Nuclear Information System (INIS)

    Walker, P.E.

    1978-01-01

    Remote systems will be required in the high-yield lithium injection fusion energy converter power plant proposed by Lawrence Livermore Laboratory. During inspection operations, viewing of the chamber interior and certain pumps, valve fittings, and welds must be done remotely. Ideas for remote maintenance of laser-beam blast baffles, optics, and target material traps are described. Radioisotope sources, their distributions, and exposure rates at various points in the reactor vicinity are presented

  5. Characterization of Decommissioned PWR Vessel Internals Material Samples: Tensile and SSRT Testing (Nonproprietary Version)

    Energy Technology Data Exchange (ETDEWEB)

    M.Krug, R.Shogan

    2004-09-01

    Pressurized water reactor (PWR) cores operate under extreme environmental conditions due to coolant chemistry, operating temperature, and neutron exposure. Extending the life of PWRs requires detailed knowledge of the changes in mechanical and corrosion properties of the structural austenitic stainless steel components adjacent to the fuel (internals) subjected to such conditions. This project studied the effects of reactor service on the mechanical and corrosion properties of samples of baffle plate, former plate, and core barrel from a decommissioned PWR.

  6. Inspection and repair of nuclear components

    International Nuclear Information System (INIS)

    Lahner, K.; Poetz, F.

    1993-01-01

    Despite careful design, manufacturing and operation, some of the important safety-relevant components show deterioration with time. Because of activation and contamination of these components, their inspection and repair has to be performed with manipulators. Some sophisticated manipulators are described, built by ABB Reaktor and used for inspection, maintenance and repair of PWR steam generators, fuel alignment pins, core baffle former bolts and reactor pressure vessel head penetrations. (Z.S.) 7 figs

  7. Optical Coating Performance for Heat Reflectors of the JWST-ISIM Electronic Component

    Science.gov (United States)

    Rashford, Robert A.; Perrygo, Charles M.; Garrison, Matthew B.; White, Bryant K.; Threat, Felix T.; Quijada, Manuel A.; Jeans, James W.; Huber, Frank K.; Bousquet, Robert R.; Shaw, Dave

    2011-01-01

    A document discusses a thermal radiator design consisting of lightweight composite materials and low-emittance metal coatings for use on the James Webb Space Telescope (JWST) structure. The structure will have a Thermal Subsystem unit to provide passive cooling to the Integrated Science Instrument Module (ISIM) control electronics. The ISIM, in the JWST observatory, is the platform that provides the mounting surfaces for the instrument control electronics. Dissipating the control electronic generated-heat away from JWST is of paramount importance so that the spacecraft s own heat does not interfere with the infrared-light gathering of distant cosmic sources. The need to have lateral control in the emission direction of the IEC (ISIM Electronics Compartment) radiators led to the development of a directional baffle design that uses multiple curved mirrorlike surfaces. This concept started out from the so-called Winston non-imaging optical concentrators that use opposing parabolic reflector surfaces, where each parabola has its focus at the opposite edge of the exit aperture. For this reason they are often known as compound parabolic concentrators or CPCs. This radiator system with the circular section was chosen for the IEC reflectors because it offers two advantages over other designs. The first is that the area of the reflector strips for a given radiator area is less, which results in a lower mass baffle assembly. Secondly, the fraction of energy emitted by the radiator strips and subsequently reflected by the baffle is less. These fewer reflections reduced the amount of energy that is absorbed and eventually re-emitted, typically in a direction outside the design emission range angle. A baffle frame holds the mirrors in position above a radiator panel on the IEC. Together, these will direct the majority of the heat from the IEC above the sunshield away towards empty space.

  8. Influence of geometrical parameters of the VVER-1000 reactor construction elements to internals irradiation conditions

    Directory of Open Access Journals (Sweden)

    О. M. Pugach

    2015-07-01

    Full Text Available Investigations to determine the influences of geometrical parameters of the calculational VVER-1000 reactor model to the results of internal irradiation condition determination are carried out. It is shown that the values of appropriate sensitivity matrix elements are not dependent on a height coordinate for any core level, but there is their azimuthal dependence. Maximum possible relative biases of neutron fluence due to inexact knowledge of internal geometrical parameters are obtained for the baffle and the barrel.

  9. A separator

    Energy Technology Data Exchange (ETDEWEB)

    Prokopyuk, S.G.; Dyachenko, A.Ye.; Mukhametov, M.N.; Prokopov, O.I.

    1982-01-01

    A separator is proposed which contains separating slanted plates and baffle plates installed at a distance to them at an acute angle to them. To increase the effectiveness of separating a gas and liquid stream and the throughput through reducing the secondary carry away of the liquid drops and to reduce the hydraulic resistance, as well, openings are made in the plates. The horizontal projections of each opening from the lower and upper surfaces of the plate do not overlap each other.

  10. Research of flow parameters in a blow off of a hydraulic installation

    OpenAIRE

    Balzannikov Mikhail; Piyavsky Semyon; Kurmanayev Аndrey

    2016-01-01

    The paper deals with conditions and parameters of water flow in a blowoff of a hydraulic installation and adjacent area of a discharge channel. The authors point out the significant impact of forms and geometric sizes of outlet structures, as well as stilling structures on the linkage parameters of outlet water flow. The article presents results of research of the impact of a baffle on the water flow in discharge outlet and outlet canal and shows a possibility of hydraulic conditions improvem...

  11. Oscillatory flow chemical reactors

    Directory of Open Access Journals (Sweden)

    Slavnić Danijela S.

    2014-01-01

    Full Text Available Global market competition, increase in energy and other production costs, demands for high quality products and reduction of waste are forcing pharmaceutical, fine chemicals and biochemical industries, to search for radical solutions. One of the most effective ways to improve the overall production (cost reduction and better control of reactions is a transition from batch to continuous processes. However, the reactions of interests for the mentioned industry sectors are often slow, thus continuous tubular reactors would be impractically long for flow regimes which provide sufficient heat and mass transfer and narrow residence time distribution. The oscillatory flow reactors (OFR are newer type of tube reactors which can offer solution by providing continuous operation with approximately plug flow pattern, low shear stress rates and enhanced mass and heat transfer. These benefits are the result of very good mixing in OFR achieved by vortex generation. OFR consists of cylindrical tube containing equally spaced orifice baffles. Fluid oscillations are superimposed on a net (laminar flow. Eddies are generated when oscillating fluid collides with baffles and passes through orifices. Generation and propagation of vortices create uniform mixing in each reactor cavity (between baffles, providing an overall flow pattern which is close to plug flow. Oscillations can be created by direct action of a piston or a diaphragm on fluid (or alternatively on baffles. This article provides an overview of oscillatory flow reactor technology, its operating principles and basic design and scale - up characteristics. Further, the article reviews the key research findings in heat and mass transfer, shear stress, residence time distribution in OFR, presenting their advantages over the conventional reactors. Finally, relevant process intensification examples from pharmaceutical, polymer and biofuels industries are presented.

  12. The British Experience in Iraq, 2007: A Perspective on the Utility of Force

    Science.gov (United States)

    2012-05-17

    66 Harry G. Summers, Jr, On Strategy: A Critical Analysis of the Vietnam War, (Novato, CA: Presidio Press, 1982). 67...that it is perhaps baffling that between 1858 and 1947 there were never more than 1000 members of the Covenanted Civil Service in India at any one time...Wars, the Korean War, the Vietnam War and the Cold War. Elaborating, he observes that the Second World War decided that the Nazi adventure in racial

  13. PENGARUH SIMULASI PENGARUH KONSENTRASI SOLID DAN GEOMETRI BIOREAKTOR MEMBRAN TERENDAM TERHADAP PERPINDAHAN MASSA GAS-LIQUID DAN FLUKS MELALUI MEMBRAN

    Directory of Open Access Journals (Sweden)

    Aisyah Endah Palupi

    2012-09-01

    Full Text Available Abstract: Hydrodynamics characteristic for the mixing of gas-solid-liquid in membrane bioreactor submerged (MBRs and its influence on mass transfer was studied computationally at various solid concentration, incoming gas rate, and the baffle distance. Computational method was conducted by using software GAMBIT 2.1.6. for the making of the grid which represents the calculation domain and conduct the simulation using CFD software FLUENT commercial code 6.2.16. Multiphase flow in reactor was simulated with mixture model, while to model the turbulence characteristic of the flow standard k-ε model was used. The geometrical system investigate is bioreactor in the form of box with flat bottom, 2 baffles, submerged membrane and air passage through the reactor bottom. The membrane type used is hollow fiber, the liquid used is water, and the solid is activated sludge, and air acts as gas phase. The result indicates that closer the baffle to the membrane, the liquid dispersion process goes faster, so that fluid in tank can be mixed perfectly and it can increase the gas-liquid mass transfer rate and the flux at MBRs. The increase of the solid concentration does not significantly affect the change of gas-liquid mass transfer rate and flux through the membrane, but the increase of air flow rate can accelerate the gas-liquid mass transfer and the flux. The position of baffle 9 cm from tank wall is the best position among the others because the amount of air flow is balanced with the circulating fluid flow. Consider from the solid distribution, double inlet MBRs is better compared to that of single inlet. Flux obtained does not show significant difference. From the both approach of the membrane model, membrane model as porous media give the simulation results closer to the experimental data.

  14. Fluid-Structure Interaction in a Fluid-Filled Composite Structure Subjected to Low Velocity Impact

    Science.gov (United States)

    2016-06-01

    this study of impact force, deflection, and strain were measured in a carbon fiber reinforced polymer (CFRP) composite cylinder subjected to low...Sanchez, J. Lopez-Puente, and D. Varas, “On the influence of filling level in CFRP aircraft fuel tank subjected to high velocity impacts,” Composite ...and back sides. The baffle provided the greatest strain reduction at the high fill levels. 14. SUBJECT TERMS glass fiber composite , fluid structure

  15. Removal of Fecal Indicators, Pathogenic Bacteria, Adenovirus, Cryptosporidium and Giardia (oocysts in Waste Stabilization Ponds in Northern and Eastern Australia

    Directory of Open Access Journals (Sweden)

    Maxim Sheludchenko

    2016-01-01

    Full Text Available Maturation ponds are used in rural and regional areas in Australia to remove the microbial loads of sewage wastewater, however, they have not been studied intensively until present. Using a combination of culture-based methods and quantitative real-time PCR, we assessed microbial removal rates in maturation ponds at four waste stabilization ponds (WSP with (n = 1 and without (n = 3 baffles in rural and remote communities in Australia. Concentrations of total coliforms, E. coli, enterococci, Campylobacter spp., Salmonella spp., F+ RNA coliphage, adenovirus, Cryptosporidium spp. and Giardia (oo cysts in maturation ponds were measured at the inlet and outlet. Only the baffled pond demonstrated a significant removal of most of the pathogens tested and therefore was subjected to further study by analyzing E. coli and enterococci concentrations at six points along the baffles over five sampling rounds. Using culture-based methods, we found a decrease in the number of E. coli and enterococci from the initial values of 100,000 CFU per 100 mL in the inlet samples to approximately 1000 CFU per 100 mL in the outlet samples for both bacterial groups. Giardia cysts removal was relatively higher than fecal indicators reduction possibly due to sedimentation.

  16. Increasing Helicity to Achieve a Dynamo State on the Three-Meter Model of the Earth's Core

    Science.gov (United States)

    Rojas, R.; Perevalov, A.; Lathrop, D. P.

    2017-12-01

    Dynamo theory describes the generation of magnetic fields in the flows of conducting fluids, for example, in stars and planetary cores. Spherical Couette flows, which are flows between two concentric and independently rotating spheres, is one of the experimental models for achieving this task in the laboratory. We have performed dynamo state search in our three-meter spherical-Couette model reaching up to Reynolds number near 108 with amplifications of the field between 10-30% but without a self-sustained dynamo magnetic field. A recent numerical work [K. Finke and A. Tilgner. Phys. Rev. E, 86:016310, Jul 2012] suggested that a roughened inner core reduces the threshold for dynamo action. The mean flow would have more poloidal component than the one we are generating with our current smooth sphere setup. With baffles flow would be expelled radially outward on the equatorial plane and returned at the poles, with opposite helicities in the two hemispheres. Baffles welded on our smooth inner sphere are proposed to achieve this task. We are working to perform experiments on a scaled water model of our experimental setup with Reynolds number near 105 to measure the helicity improvements of different baffle designs in support of upcoming Three-Meter modifications. We gratefully acknowledge support from NSF EAR-1417148.

  17. Optimization of a Finned Shell and Tube Heat Exchanger Using a Multi-Objective Optimization Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Heidar Sadeghzadeh

    2015-08-01

    Full Text Available Heat transfer rate and cost significantly affect designs of shell and tube heat exchangers. From the viewpoint of engineering, an optimum design is obtained via maximum heat transfer rate and minimum cost. Here, an analysis of a radial, finned, shell and tube heat exchanger is carried out, considering nine design parameters: tube arrangement, tube diameter, tube pitch, tube length, number of tubes, fin height, fin thickness, baffle spacing ratio and number of fins per unit length of tube. The “Delaware modified” technique is used to determine heat transfer coefficients and the shell-side pressure drop. In this technique, the baffle cut is 20 percent and the baffle ratio limits range from 0.2 to 0.4. The optimization of the objective functions (maximum heat transfer rate and minimum total cost is performed using a non-dominated sorting genetic algorithm (NSGA-II, and compared against a one-objective algorithm, to find the best solutions. The results are depicted as a set of solutions on a Pareto front, and show that the heat transfer rate ranges from 3517 to 7075 kW. Also, the minimum and maximum objective functions are specified, allowing the designer to select the best points among these solutions based on requirements. Additionally, variations of shell-side pressure drop with total cost are depicted, and indicate that the pressure drop ranges from 3.8 to 46.7 kPa.

  18. Improvements in or relating to radiography

    International Nuclear Information System (INIS)

    Oliver, C.C.

    1980-01-01

    Apparatus for improving the performance of CAT scanners is described in detail. It consists of a novel design of collimators or baffles which are interposed between the fan-shaped X-ray beam and the detectors. The baffles are arranged such that they are tilted at an angle with respect to the junctions between the detectors. Thus the amount of baffle overlying each detector (and elastic anisotropy is close to unity at room temperature, consequently attenuating the X-ray beam) is constant during an integration period of the scan. This means that the timing of the integration periods does not need to be as precise as for CAT scanners utilising conventional collimators. Furthermore, by arranging the fan-shaped X-ray beam to be wider than the patient being examined, then each detector will receive the direct output of the X-ray source in turn. The output signals received at these times can be used as calibration signals to normalise the response of the various detectors. An example of how to use the new collimator in a CAT scanner is given. (U.K.)

  19. A study on the relief of shell wall thinning of high pressure feedwater heater

    International Nuclear Information System (INIS)

    Kim, Hyung Joon; Park, Sang Hoon; Seo, Hyuk Ki; Kim, Kyung Hoon; Hwang, Kyung Mo

    2008-01-01

    Feedwater heaters of many nuclear power plants have recently experienced severe wall thinning damage, which will increase as operating time progresses. Several nuclear power plants in Korea have experienced wall thinning damage in the area around the impingement baffle-installed downstream of the high pressure turbine extraction stream line- inside number 5A and 5B feedwater heaters. At that point, the extracted steam from the high pressure turbine is two phase fluid at high temperature, high pressure, and high speed. Since it flows in reverse direction after impinging the impingement baffle, the shell wall of the number 5 high pressure feedwater heater may be affected by flow-accelerated corrosion. This paper describes operation of experience and numerical analysis composed similar condition with real high pressure feedwater heater. This study applied squared, curved and new type impingement baffle plates to feedwater heater same as previous study. In addition, it shows difference of pressure distribution and value between single phase and two phase based on experience and numerical analysis

  20. Installation for the suppression of sodium fires

    International Nuclear Information System (INIS)

    Newman, R.N.; Payne, J.F.B.; Lee, C.J.; Rowe, D.M.J.

    1979-01-01

    The basic operating principles are discussed of a passive baffle-catch tray fire suppression system for sodium fires. A new design is described incorporating increased compartmentalization of the collecting and drainage parts of the device. The burning and smoke generation rates from trays with varying aperture sizes were measured. From the experiments it was found that the burning rate and smoke generation rates could be related satisfactorily to the aperture areas. For the smallest aperture size ( 2 ) it was found that the smoke release was considerably less than that from a fire of the same area, because the smoke deposited on the underside of the baffle. A re-ignition problem was found, where pillars of sodium oxide (wicks) grow upward from the surface of the drained sodium and begin to burn when level with the baffle aperature. From a knowledge of the rate of growth of the wicks, trays may be made sufficiently deep to avoid the problem. Self acting valves were developed which allow the passage of sodium through the aperture and close when drainage is complete. These devices were shown to effect complete extinction of the drained sodium. Using the designs proposed it is possible to construct a system that will reduce the smoke emission from the drained sodium by a factor approaching 10 3 , without the use of valves, or with the self acting valves developed, reduce the emission from the drained sodium to approximately zero. (author)

  1. Giant coronary artery aneurysm after Takeuchi repair for anomalous left coronary artery from the pulmonary artery.

    Science.gov (United States)

    Dunlay, Shannon M; Bonnichsen, Crystal R; Dearani, Joseph A; Warnes, Carole A

    2014-01-01

    A 33-year-old woman with an anomalous left coronary artery arising from the pulmonary artery who had undergone Takeuchi repair at age 7 years presented for evaluation. The Takeuchi procedure creates an aortopulmonary window and an intrapulmonary tunnel that baffles the left coronary artery to the aorta. A mediastinal mass was identified as a giant aneurysm of the left coronary artery resulting in compression of the pulmonary artery and left upper pulmonary vein. The patient underwent open repair with patch closure at the aortic entrance of the left coronary Takeuchi repair and resection and evacuation of the aneurysm. A saphenous vein graft to the left anterior descending artery was performed. Postoperative echocardiography demonstrated normal left ventricular function. This is the first reported case of giant aneurysm formation after Takeuchi repair. The reported complications have included the development of pulmonary artery stenosis at the intrapulmonary baffle, baffle leak, decreased left ventricular function, and mitral regurgitation. In conclusion, late complications of the Takeuchi procedure are common, underscoring the importance of lifelong follow-up at a center with experience in treating coronary anomalies. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Fireplace with preheated secondary air supply

    Energy Technology Data Exchange (ETDEWEB)

    Scheler, P. E.

    1985-09-24

    A fireplace cap is positioned outside the firebox of the fireplace. The cap has a framework comprised of first and second side members, an upper cross member and a lower damper section. A pair of hinged doors are mounted to this framework. Dampers selectively control the passage of primary combustion air directly to the firebox. A mantel overlies the upper cross member and a secondary air deflector baffle extends downwardly from the underside of the mantel. This baffle, together with the upper cross member, defines a transversely extending secondary air preheating chamber. Preheated air from the chamber is directed by the baffle across the doors prior to passing into the firebox. In one embodiment, secondary air enters the chamber through a space between the mantel and upper cross member. A valve controls the flow of secondary air to this space. In another embodiment, the damper section and side members define passageways which direct outside combustion air upwardly along the sides of the cap and into the chamber. Valves in the side passageways control the flow of air to the chamber.

  3. Tube vibration in industrial size test heat exchanger

    International Nuclear Information System (INIS)

    Halle, H.; Wambsganss, M.W.

    1980-03-01

    Tube vibration data from tests of a specially built and instrumented, industrial-type, shell-and-tube heat exchanger are reported. The heat exchanger is nominally 0.6 m (2 ft) in dia and 3.7 m (12 ft) long. Both full tube and no-tubes-in-window bundles were tested for inlet/outlet nozzles of different sizes and with the tubes supported by seven, equally-spaced, single-segmental baffles. Prior to water flow testing, natural frequencies and damping of representative tubes were measured in air and water. Flow testing was accomplished by increasing the flow rates in stepwise fashion and also by sweeping through a selected range of flow rates. The primary variables measured and reported are tube accelerations and/or displacements and pressure drop through the bundle. Tests of the full tube bundle configuration revealed tube rattling to occur at intermediate flow rates, and fluidelastic instability, with resultant tube impacting, to occur when the flow rate exceeded a threshold level; principally, the four-span tubes were involved in the regions immediately adjacent to the baffle cut. For the range of flow rates tested, fluidelastic instability was not achieved in the no-tubes-in-window bundle; in this configuration the tubes are supported by all seven baffles and are, therefore, stiffer

  4. Influences of the wavy surface inserted in the middle of a circular tube heat exchanger on thermal performance

    Energy Technology Data Exchange (ETDEWEB)

    Jedsadaratanancai, Withada [King Mongkut' s Institute of Technology Ladkrabang, Bangkok (Thailand); Boonloi, Amnart [King Mongkut' s University of Technology North Bangkok, Bangkok (Thailand)

    2015-09-15

    Numerical investigations on flow topology, heat transfer behavior and performance evaluation in a circular tube inserted with various configurations of wavy surfaces, Inclined wavy surface (IWS), V-downstream wavy surface (VDWS), V-Upstream wavy surface (VUWS) are presented. The effects of the flow attack angles; 20 .deg., 30 .deg., 45.deg. and 60.deg. are studied for the Reynolds numbers, Re = 100-2000. The numerical results are compared with the smooth circular tube with no wavy surface and the previous works. It is found that the IWS, VDWS and VUWS can produce longitudinal vortex flow and impinging jet of the fluid flow like inclined baffle, V-downstream baffle and V-Upstream baffle, respectively, but give lower friction loss. The flow phenomena created by the wavy surfaces help to augment the heat transfer rate and thermal performance in the test tube. In the range studied, the order of enhancement for heat transfer rate is around 1.40-3.75, 1.60-6.25 and 1.30-5.80 times higher than the smooth tube for IWS, VDWS and VUWS, respectively. Moreover, the maximum thermal performance, presented in terms of the Thermal enhancement factor (TEF), is found to be about 1.60, 2.40 and 2.10, respectively, for IWS, VUWS and VDWS.

  5. Evaluation of Boundary Dam spillway using an Autonomous Sensor Fish Device

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Z. D.; Duncan, J. P.; Arnold, J. L.; Fu, T.; Martinez, J.; Lu, J.; Titzler, P. S.; Zhou, D.; Mueller, R. P.

    2017-03-01

    Fish passage conditions over spillways are important for the operations of hydroelectric dams because spillways are usually considered as a common alternative passage route to divert fish from the turbines. The objectives of this study were to determine the relative potential of fish injury during spillway passage both before and after the installation of baffle blocks at Boundary Dam, and to provide validation data for a model being used to predict total dissolved gas levels. Sensor Fish were deployed through a release system mounted on the face of the dam in the forebay. Three treatments, based on the lateral position on the spillway, were evaluated for both the baseline and post-modification evaluations: Left Middle, Right Middle, and Right. No significant acceleration events were detected in the forebay, gate, or transition regions for any release location; events were only observed on the chute and in the tailrace. Baseline acceleration events observed in the chute region were all classified as strikes, whereas post-modification events included strike and shear on the chute. While the addition of baffle blocks increased the number of significant events observed on the spillway chute, overall fewer events were observed in the tailrace post-modification. Analysis of lateral positioning of passage indicated that the Right Middle treatment was potentially less injurious to fish based on relative frequency of significant events at each location. The construction of baffle blocks on the spillway visibly changed the flow regime. Prior to installation the flow jet was relatively thin, impacting the tailrace as a coherent stream that plunged deeply, possibly contributing to total dissolved gas production. Following baffle block construction, the discharge jet was more fragmented, potentially disrupting the plunge depth and decreasing the time that bubbles would be at depth in the plunge pool. The results in this study support the expected performance of the modified

  6. Impact of anatomic characteristics and initial biventricular surgical strategy on outcomes in various forms of double-outlet right ventricle.

    Science.gov (United States)

    Villemain, Olivier; Belli, Emre; Ladouceur, Magalie; Houyel, Lucile; Jalal, Zakaria; Lambert, Virginie; Ly, Mohamed; Vouhé, Pascal; Bonnet, Damien

    2016-09-01

    Surgical management of various forms of double-outlet right ventricle uses a variety of approaches depending on the underlying anatomic form. In this study, we sought to determine the risk factors of mortality and reoperation in those with double-outlet right ventricle undergoing biventricular repair, according to anatomic characteristics and initial surgical strategy. Between 1992 and 2013, 433 patients were included in the study. Double-outlet right ventricle was classified as double-outlet right ventricle with subaortic ventricular septal defect associated with subpulmonary obstruction in 33% of patients (n = 141), with subaortic ventricular septal defect without subpulmonary obstruction in 30% of patients (n = 130), with subpulmonary ventricular septal defect in 32% of patients (n = 139), and with noncommitted ventricular septal defect in 5% of patients (n = 23). Three types of repairs were performed: (1) intraventricular baffle repair, n = 149 (34%); (2) intraventricular baffle repair with right ventricular outflow tract reconstruction, n = 163 (38%); and (3) intraventricular baffle repair with arterial switch operation, n = 121 (28%). Thirty-day overall mortality was 7.4%. Early reoperation was needed in 6% of the cases. Early mortality was higher in the intraventricular baffle repair with arterial switch operation group (P = .01). Survival at 10 years was 86.2%, and freedom from reoperation at 10 years was 61.4%. At last follow-up (median, 5.7 years; 95% confidence interval, 4.5-6.6), mortality and reoperation rates were similar in the different surgical strategy groups. Late reoperation and late mortality were significantly higher in the double-outlet right ventricle with noncommitted ventricular septal defect group (P outlet right ventricle with noncommitted ventricular septal defect were at higher risk for reoperation and mortality. Intraventricular baffle repair with arterial switch operation was the surgical strategy in patients at

  7. Technology demonstration for reducing mercury emissions from small-scale gold refining facilities.

    Energy Technology Data Exchange (ETDEWEB)

    Habegger, L. J.; Fernandez, L. E.; Engle, M.; Bailey, J. L.; Peterson, D. P.; MacDonell, M. M.; U.S. Environmental Protection Agency

    2008-06-30

    Gold that is brought from artisanal and small-scale gold mining areas to gold shops for processing and sale typically contains 5-40% mercury. The uncontrolled removal of the residual mercury in gold shops by using high-temperature evaporation can be a significant source of mercury emissions in urban areas where the shops are located. Emissions from gold shop hoods during a burn can exceed 1,000 mg/m{sup 3}. Because the saturation concentration of mercury vapor at operating temperatures at the hood exhaust is less than 100 mg/m{sup 3}, the dominant component of the exhaust is in the form of aerosol or liquid particles. The U.S. Environmental Protection Agency (EPA), with technical support from Argonne National Laboratory (Argonne), has completed a project to design and test a technology to remove the dominant aerosol component in the emissions from gold shops. The objective was to demonstrate a technology that could be manufactured at low cost and by using locally available materials and manufacturing capabilities. Six prototypes designed by Argonne were locally manufactured, installed, and tested in gold shops in Itaituba and Creporizao, Brazil. The initial prototype design incorporated a pebble bed as the media for collecting the mercury aerosols, and a mercury collection efficiency of over 90% was demonstrated. Though achieving high efficiencies, the initial prototype was determined to have practical disadvantages such as excessive weight, a somewhat complex construction, and high costs (>US$1,000). To further simplify the construction, operation, and associated costs, a second prototype design was developed in which the pebble bed was replaced with slotted steel baffle plates. The system was designed to have flexibility for installation in various hood configurations. The second prototype with the baffle plate design was installed and tested in several different hood/exhaust systems to determine the optimal installation configuration. The significance of

  8. Building an Experimental Setup to Characterize an H4RG-15

    Science.gov (United States)

    Hirata, Mickie; Hodapp, K.; Hall, Donald N. B.; Goebel, Sean B.; Jacobson, Shane M.

    2018-01-01

    The Teledyne Imaging Sensors H4RG-15 infrared detector is designed for the next era of extremely large telescopes. Characterization of individual H4RG-15 detectors are critical for future astronomical use. ULBcam, a former UH88 IR camera and remnant test dewar for H2RG characterization, was previously modified for H4RG-15 characterization. During the summer, this system was further upgraded with a baffle tube to a blackbody illumination source to allow controlled field illumination. This baffle tube, designed in OpenSCAD, was constructed in the IfA machine shop. Specific placements of the 50-micron aperture and scatter restrictive baffling was designed in Zemax. Four separate data sets were acquired to look into detector persistence, dark current, read noise, and charge gain. With the illumination source set at 450 K, ten ramps of 90/90 read frames were taken to pass saturation values. These tests were repeated at 500K to show results at over saturated conditions. Five ramps of 136/136 read frames were taken with a blank shutter applied. The persistence results showed expected results with signals settling from the third ramp. Dark current results showed higher than Teledyne stated values at 0.06 electrons/second, a factor of 6 higher than expected, which exposes systematic ULBcam dark testing capabilities. The read noise resulted with an expected value of 0.014 electrons. The charge gain showed 0.02 electrons/ADU where the expected value is 2 electrons/ADU. Data analysis using reference frame subtraction will be done for future work.

  9. Fabrication and installation of the DIII-D radiative divertor structures

    International Nuclear Information System (INIS)

    Hollerbach, M.A.; Smith, J.P.

    1997-11-01

    Phase 1A of the Radiative Divertor Program (RDP) is now installed in the DIII-D tokamak located at General Atomics. This hardware was added to enhance both the Divertor and Advanced Tokamak research elements of the DIII-D program. This installation consists of a divertor baffle enveloping a cryocondensation pump at the upper outer divertor target of DIII-D. The divertor baffle consists of two toroidally continuous Inconel 625 water-cooled rings and a toroidal array of discontinuous radiatively-cooled plates. The water-cooled rings are each comprised of four quadrants, mechanically formed, chem.-milled, and resistance and TIG welded Inconel 625 panels. The supports attaching the panels to the vessel wall are designed to accommodate the differential thermal expansion between the rings and vessel during bake and to react the electromagnetic loads induced during disruptions. They are made from either Inconel 625 or Inconel 718 depending on the stress levels predicted in Finite Element Analysis. Gas seals are designed to limit the leakage from the baffle chamber back to the core plasma to 2,500 ell/s and incorporate plasma sprayed alumina to minimize currents flowing through them. The bulk of the water-cooled ring fabrication was performed by a vendor, however, the final machining of penetrations in the conical ring for diagnostic access was performed in-house using a unique machining configuration. This configuration, and the machining of the diagnostic cutouts is described. Graphite tiles were machined from ATJ graphite to form a smooth plasma-facing surface. The installation of all divertor components required only four weeks

  10. Influence of Shading on Cooling Energy Demand

    Science.gov (United States)

    Rabczak, Sławomir; Bukowska, Maria; Proszak-Miąsik, Danuta; Nowak, Krzysztof

    2017-10-01

    The article presents an analysis of the building cooling load taking into account the variability of the factors affecting the size of the heat gains. In order to minimize the demand for cooling, the effect of shading elements installed on the outside on the windows and its effect on size of the cooling capacity of air conditioning system for the building has been estimated. Multivariate building cooling load calculations to determine the size of the reduction in cooling demand has derived. Determination of heat gain from the sun is laborious, but gives a result which reflects the influence of the surface transparent partitions, devices used as sunscreen and its location on the building envelope in relation to the world, as well as to the internal heat gains has great attention in obtained calculation. In this study, included in the balance sheet of solar heat gains are defined in three different shading of windows. Calculating the total demand cooling is made for variants assuming 0% shading baffles transparent, 50% shading baffles transparent external shutters at an angle of 45 °, 100% shading baffles transparent hours 12 from the N and E and from 12 from the S and W of the outer slat blinds. The calculation of the average hourly cooling load was taken into account the option assuming the hypothetical possibility of default by up to 10% of the time assumed the cooling season temperatures in the rooms. To reduce the consumption of electricity energy in the cooling system of the smallest variant identified the need for the power supply for the operation of the cooling system. Also assessed the financial benefits of the temporary default of comfort.

  11. Preliminary results on the EUCLID NISP stray-light and ghost analysis

    Science.gov (United States)

    Geis, Norbert; Grupp, Frank; Prieto, Eric; Bender, Ralf

    2015-09-01

    The EUCLID mission within the European Space Agencies 2015 - 2025 Cosmic Vision framework addresses cosmological questions related to dark matter and dark energy. EUCLID is equipped with two instruments that are simultaneously observing patches of > 0:5 square degree on the sky. The VIS visual light high spacial resolution imager and the NISP near infrared spectrometer and photometer are separated by a di-chroic beam splitter. With its large FoV (larger than the full moon disk), together with high demands on the optical performance and strong requirements on in flight stability lead to very challenging demands on alignment and post launch { post cool-down optical element position. In addition the demanding requirements from spectroscopy and galaxy photometry lead to a highly demanding stray light and ghost control need. With this paper we present a preliminary - PDR level - analysis of ghosting and stray light levels in the EUCLID NISP near infrared spectrometer and photometer. The analysis presented focuses on the photometric channel, as this, together with the wide field of the instrument, shows most of the challenges and features of the instrument. As one requirement is to have a non vignetting design, extensive baffling is not possible, and only secondary and higher order light can be actively baffled. A comprehensive ZEMAX based analysis is being presented, showing in summary that baffles are only necessary due to the EUCLID fine guiding sensors auxiliary fields of view. The total level of contaminating light is thereafter dominated by stray light from dust on the lenses. Ghosts play a minor role.

  12. Optimized chemical composition, working and heat treatment condition for resistance to irradiation assisted stress corrosion cracking of cold worked 316 and high-chromium austenitic stainless steel

    International Nuclear Information System (INIS)

    Yonezawa, Toshio; Iwamura, Toshihiko; Fujimoto, Koji; Ajiki, Kazuhide

    2000-01-01

    The authors have reported that the primary water stress corrosion cracking (PWSCC) in baffle former bolts made of austenitic stainless steels for PWR after long-term operation is caused by irradiation-induced grain boundary segregation. The resistance to PWSCC of simulated austenitic stainless steels whose chemical compositions are simulated to the grain boundary chemical composition of 316 stainless steel after irradiation increased with decrease of the silicon content, increases of the chromium content, and precipitation of M 23 C 6 carbides at the grain boundaries. In order to develop resistance to irradiation assisted stress corrosion cracking in austenitic stainless steels, optimized chemical compositions and heat treatment conditions for 316CW and high-chromium austenitic stainless steels for PWR baffle former bolts were investigated. For 316CW stainless steel, ultra-low-impurities and high-chromium content are beneficial. About 20% cold working before aging and after solution treatment has also been recommended to recover sensitization and make M 23 C 6 carbides coherent with the matrix at the grain boundaries. Heating at 700 to 725degC for 20 to 50 h was selected as a suitable aging procedure. Cold working of 5 to 10% after aging produced the required mechanical properties. The optimized composition of the high-chromium austenitic stainless steel contents 30% chromium, 30% nickel, and ultra-low impurity levels. This composition also reduces the difference between its thermal expansion coefficient and that of 304 stainless steel for baffle plates. Aging at 700 to 725degC for longer than 40 h and cold working of 10 to 15% after aging were selected to meet mechanical property specifications. (author)

  13. Increased rate of chondrocyte aggregation in a wavy-walled bioreactor.

    Science.gov (United States)

    Bueno, Ericka M; Bilgen, Bahar; Carrier, Rebecca L; Barabino, Gilda A

    2004-12-20

    A novel wavy-walled bioreactor designed to enhance mixing at controlled shear stress levels was used to culture chondrocytes in suspension. Chondrocyte aggregation in suspensions mixed at 30, 50, and 80 rpm was characterized in the wavy-walled bioreactor and compared with that in conventional smooth-walled and baffled-walled spinner flask bioreactors. Aggregation was characterized in terms of the percentage of cells that aggregated over time, and aggregate size changes over time. The kinetics of chondrocyte aggregation observed in the bioreactors was composed of two phases: early aggregation between 0 and 2 h of culture, and late aggregation between 3 and 24 h of culture. At 50 rpm, the kinetics of early aggregation in the wavy-walled bioreactor was approximately 25% and 65% faster, respectively, than those in the smooth-walled and baffled-walled spinner flask bioreactors. During the late aggregation phase, the kinetics of aggregation in the wavy-walled bioreactor were approximately 45% and 65% faster, respectively, than in the smooth-walled and baffled-walled spinner flasks. The observed improved kinetics of chondrocyte aggregation was obtained at no cost to the cell survival rate. Results of computerized image analysis suggest that chondrocyte aggregation occurred initially by the formation of new aggregates via cell-cell interactions and later by the joining of small aggregates into larger cell clumps. Aggregates appeared to grow for only a couple of hours in culture before reaching a steady size, possibly determined by limitations imposed by the hydrodynamic environment. These results suggest that the novel geometry of the wavy-walled bioreactor generates a hydrodynamic environment distinct from those traditionally used to culture engineered cartilage. Such differences may be useful in studies aimed at distinguishing the effects of the hydrodynamic environment on tissue-engineered cartilage. Characterizing the wavy-walled bioreactor's hydrodynamic environment

  14. Numerical study of effect of wall parameters on catalytic combustion characteristics of CH4/air in a heat recirculation micro-combustor

    International Nuclear Information System (INIS)

    Yan, Yunfei; Wang, Haibo; Pan, Wenli; Zhang, Li; Li, Lixian; Yang, Zhongqing; Lin, Changhai

    2016-01-01

    Highlights: • Combustion in heat recuperation micro-combustors with different materials was studied. • Heat concentration is more obvious with thermal conductivity decreasing. • Combustor with copper baffles has uniform temperature distribution and best preheating effectiveness. • Influence of wall thermal conductivity is negligible on OH(s) coverage. • Methane conversion rate firstly increases and then decreases with h increasing. - Abstract: Premixed combustion of methane/air mixture in heat recuperation micro-combustors made of different materials (corundum, quartz glass, copper and ferrochrome) was investigated. The effects of wall parameters on the combustion characters of a CH 4 /air mixture under Rhodium catalyst as well as the influence of wall materials and convection heat transfer coefficients on the stable combustion limit, temperature field, and free radicals was explored using numerical analysis methodology. The results show that with a decrease of thermal conductivity of wall materials, the temperature of the reaction region increases and hot spots becomes more obvious. The combustor with copper baffles has uniform temperature distribution and best preheating effectiveness, but when inlet velocity is too small, the maximum temperature in the combustor with copper or ferrochrome baffles is well beyond the melting point of the materials. With an increase in thermal conductivity, the preheat zone for premixed gas increases, but the influence of thermal conductivity on OH(s) coverage is negligible. With an increase of the wall convection heat transfer coefficient, the methane conversion rate firstly increases, then decreases reaching a maximum value at h = 8.5 W/m 2 K, however, the average temperature of both the axis and exterior surface of the combustor decrease.

  15. Increased Power in Sediment Microbial Fuel Cell: Facilitated Mass Transfer via a Water-Layer Anode Embedded in Sediment

    OpenAIRE

    Lee, Yoo Seok; An, Junyeong; Kim, Bongkyu; Park, HyunJun; Kim, Jisu; Chang, In Seop

    2015-01-01

    We report a methodology for enhancing the mass transfer at the anode electrode of sediment microbial fuel cells (SMFCs), by employing a fabric baffle to create a separate water-layer for installing the anode electrode in sediment. The maximum power in an SMFC with the anode installed in the separate water-layer (SMFC-wFB) was improved by factor of 6.6 compared to an SMFC having the anode embedded in the sediment (SMFC-woFB). The maximum current density in the SMFC-wFB was also 3.9 times highe...

  16. MBT - skoen der sælger sig selv Branding og dens rolle i moderne markedsføring

    OpenAIRE

    Tengberg, Niels

    2013-01-01

    Despite the time and money spent on market reearch through focus group and questionnaires, 60 to 80 % of all new products and services fail. Why do consumers often say one thing to marketers, yet do something entirely different in the market? The aim of this thesis is to: - Penetrate the mystery that baffles marketers in every industry: why customers don´t buy proucts and services that they instist they want. - Understand how a customer´s buying decision is influenced by the complex interacti...

  17. Nuclear fuel storage apparatus for seismic areas

    International Nuclear Information System (INIS)

    Anthony, A.J.

    1981-01-01

    An earthquake resistant apparatus is claimed for storing nuclear fuel within a water-filled pool wherein a structural grid which supports the fuel is in turn supported by cables from an upper elevation. The grid is located below the water level and spaced from the walls of the pool an amount, preferably at least equal to the anticipated earthquake displacement. The grid is located below the water level a sufficient depth for radiation shielding during fuel handling and storage, and tension members are preferably ten times the design earthquake displacement. A horizontal baffle is located around the periphery of the pool at an elevation above the grid

  18. Energy Dissipation Rate in an Agitated Crucible Containing Molten Metal

    Science.gov (United States)

    Li, Tao; Shimasaki, Shin-ichi; Narita, Shunsuke; Taniguchi, Shoji

    2017-10-01

    The energy dissipation rate (EDR) is an important parameter for characterizing the behavior of inclusion coagulation in agitated molten metal. To clarify the inclusion coagulation mechanism, we review previous water model studies by particularly focusing on the relation between the impeller torque and the EDR of the fluid, which indicates the ratio of energy dissipated in the viscous medium to the energy inputted by the rotating impeller. In the present study, simulations coupled with experiments were performed to determine the relation between the torque and the effective EDR for water and liquid Al in crucibles with and without baffles.

  19. Chemical vapor deposition reactor. [providing uniform film thickness

    Science.gov (United States)

    Chern, S. S.; Maserjian, J. (Inventor)

    1977-01-01

    An improved chemical vapor deposition reactor is characterized by a vapor deposition chamber configured to substantially eliminate non-uniformities in films deposited on substrates by control of gas flow and removing gas phase reaction materials from the chamber. Uniformity in the thickness of films is produced by having reactive gases injected through multiple jets which are placed at uniformally distributed locations. Gas phase reaction materials are removed through an exhaust chimney which is positioned above the centrally located, heated pad or platform on which substrates are placed. A baffle is situated above the heated platform below the mouth of the chimney to prevent downdraft dispersion and scattering of gas phase reactant materials.

  20. Electrowinning of cobalt from sulfate-chloride and sulfate solutions of cobalt and manganese under dynamic conditions

    Directory of Open Access Journals (Sweden)

    Л. П. Хоменко

    2017-08-01

    Full Text Available The design of an electrolyzer for electrowinning in dynamic conditions is developed. The dependence of the results of electrowinning of cobalt and manganese from sulfate and sulfate-chloride solutions under dynamic conditions using a titanium cathode and a lead anode with 1 % of silver was studied. It was found that the best extraction results for the current yield and the specific energy consumption were obtained by electrolysis from sulfate solutions at a low concentration of manganese in an electrolyser without a perforated baffle plate separating the cathode and anode spaces.

  1. Key factors affecting on bio-hydrogen production from co-digestion of organic fraction of municipal solid waste and kitchen wastewater.

    Science.gov (United States)

    Tawfik, Ahmed; El-Qelish, Mohamed

    2014-09-01

    The effects of sludge residence time (SRT) and dilution ratio (DR) on the continuous H2 production (HP) from co-digestion of organic fraction of municipal solid waste (OFMSW) and kitchen wastewater (KWW) via mesophilic anaerobic baffled reactor (ABR) was investigated. Increasing DR from 1:2 to 1:3 significantly (Phydrogen fermentation facilitated carbohydrate, lipids, protein and volatile solids removal efficiencies of 87±5.8%, 74.3±9.12%, 76.4±11.3% and 84.8±4.1%, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Acoustic Effects Accurately Predict an Extreme Case of Biological Morphology

    Science.gov (United States)

    Zhang, Zhiwei; Truong, Son Nguyen; Müller, Rolf

    2009-07-01

    The biosonar system of bats utilizes physical baffle shapes around the sites of ultrasound emission for diffraction-based beam forming. Among these shapes, some extreme cases have evolved that include a long noseleaf protrusion (sella) in a species of horseshoe bat. We have evaluated the acoustic cost function associated with sella length with a computational physics approach and found that the extreme length can be predicted accurately from a fiducial point on this function. This suggests that some extreme cases of biological morphology can be explained from their physical function alone.

  3. Plasma facing components design of KT-2 tokamak

    International Nuclear Information System (INIS)

    In, Sang Ryul; Yoon, Byung Joo; Song, Woo Soeb; Xu, Chao Yin

    1997-04-01

    The vacuum vessel of KT-2 tokamak is protected from high thermal loads by various kinds of plasma facing components (PFC): outer and inner divertors, neutral baffle, inboard limiter, poloidal limiter, movable limiter and passive plate, installed on the inner wall of the vessel. In this report the pre-engineering design of the plasma facing components, including design requirements and function, structures of PFC assemblies, configuration of cooling systems, calculations of some mechanical and hydraulic parameters, is presented. Pumping systems for the movable limiter and the divertor are also discussed briefly. (author). 49 figs

  4. Design of a cyclic multiverse

    Energy Technology Data Exchange (ETDEWEB)

    Piao Yunsong, E-mail: yspiao@gucas.ac.c [College of Physical Sciences, Graduate School of Chinese Academy of Sciences, Beijing 100049 (China)

    2010-08-09

    Recently, it has been noticed that the amplification of the amplitude of curvature perturbation cycle by cycle can lead to a cyclic multiverse scenario, in which the number of universes increases cycle by cycle. However, this amplification will also inevitably induce either the ultimate end of corresponding cycle, or the resulting spectrum of perturbations inside corresponding universe is not scale invariant, which baffles the existence of observable universes. In this Letter, we propose a design of a cyclic multiverse, in which the observable universe can emerges naturally. The significance of a long period of dark energy before the turnaround of each cycle for this implementing is shown.

  5. Proposed examination of defect detection of magnetic tube where alternating probe in type of insertion is used

    International Nuclear Information System (INIS)

    Kiya, Atsushi; Gotoh, Yuji; Sakurai, Kenta

    2008-01-01

    In various plants in the thermal power plant and the nuclear plant, a lot of steel tubes are used for various places such as heat exchangers, and these steel tubes should inspect regular for a healthy securing of the plant. Then, the outer side defect inspection of the magnetic substance steel tube using an electromagnetic phenomenon was examined in this research. It is shown that the inspection of the outer side defect on a steel tube with baffle is possible using the proposed method. (author)

  6. Safety and security risk assessments--now demystified!

    Science.gov (United States)

    White, Donald E

    2011-01-01

    Safety/security risk assessments no longer need to spook nor baffle healthcare safety/security managers. This grid template provides at-at-glance quick lookup of the possible threats, the affected people and things, a priority ranking of these risks, and a workable solution for each risk. Using the standard document, spreadsheet, or graphics software already available on your computer, you can easily use a scientific method to produce professional looking risk assessments that get quickly understood by both senior managers and first responders alike!

  7. FINAL REPORT FOR THE DIII-D RADIATIVE DIVERTOR PROJECT

    International Nuclear Information System (INIS)

    O'NEIL, RC; STAMBAUGH, RD

    2002-01-01

    OAK A271 FINAL REPORT FOR THE DIII-D RADIATIVE DIVERTOR PROJECT. The Radiative Divertor Project originated in 1993 when the DIII-D Five Year Plan for the period 1994--1998 was prepared. The Project Information Sheet described the objective of the project as ''to demonstrate dispersal of divertor power by a factor of then with sufficient diagnostics and modeling to extend the results to ITER and TPX''. Key divertor components identified were: (1) Carbon-carbon and graphite armor tiles; (2) The divertor structure providing a gas baffle and cooling; and (3) The divertor cryopumps to pump fuel and impurities

  8. A DESIGN RETROSPECTIVE OF THE DIII-D TOKAMAK

    International Nuclear Information System (INIS)

    LUXON, J.L

    2001-06-01

    OAK-B135 The DIII-D tokamak evolved from the earlier Doublet III device in 1986. Since then, the facility has undergone a number of changes including the installation of divertor baffles and pumping chambers in the vacuum vessel, the addition of a radiation shield, the development of extensive neutral beam and rf heating systems, and the addition of a comprehensive plasma control system. The facility has become the focus of a broad fusion plasma science research program. This paper gives an integrated picture of the facility and its capabilities

  9. Processes for the production of ultra-pure metals from oxide and their cold rolling to ultra-thin foils for use as targets and as reference materials

    International Nuclear Information System (INIS)

    Clifford, S.; Guo-ji, Xu; Ingelbrecht, C.; Pomeroy, M.J.

    2002-01-01

    A wide variety of metals have been reduced from their oxides with high (>90%) yields using metallothermic reduction, hydrogen reduction or electrowinning. The high yields during metallothermic reduction were achieved by careful design of the collector and crucible orifice. Whilst each of the three techniques gave rise to reasonably (>99%) pure metals, subsequent carefully controlled vacuum distillation, using a system with especially designed crucible, baffle and collector systems, resulted in ultra-high-purity metals being produced. Using a stainless steel pack rolling technique, metals derived either directly from the reduction routes or following subsequent distillation could be rolled to foils thinner than previously reported in the literature in the majority of cases

  10. Development and Testing of Active Groundwater Samplers

    DEFF Research Database (Denmark)

    Nilsson, Bertel; Jakobsen, Rasmus; Andersen, Lars Jørgen

    1995-01-01

    Baffle System (PBS). The methodology and design of the two systems is presented and the operational application is demonstrated by examples from full-scale field experiments. The methods are validated and their sensitivity to the well construction and the hydrogeological environment is assessed based...... on numerical modelling and controlled laboratory experiments. Active groundwater sampling techniques can be used for remedial pumping optimization and in obtaining hydraulic data and represent a fast operational and reliable sampling tool, also under heterogeneous and low permeability conditions....

  11. An extension to artifact-free projection overlaps

    International Nuclear Information System (INIS)

    Lin, Jianyu

    2015-01-01

    Purpose: In multipinhole single photon emission computed tomography, the overlapping of projections has been used to increase sensitivity. Avoiding artifacts in the reconstructed image associated with projection overlaps (multiplexing) is a critical issue. In our previous report, two types of artifact-free projection overlaps, i.e., projection overlaps that do not lead to artifacts in the reconstructed image, were formally defined and proved, and were validated via simulations. In this work, a new proposition is introduced to extend the previously defined type-II artifact-free projection overlaps so that a broader range of artifact-free overlaps is accommodated. One practical purpose of the new extension is to design a baffle window multipinhole system with artifact-free projection overlaps. Methods: First, the extended type-II artifact-free overlap was theoretically defined and proved. The new proposition accommodates the situation where the extended type-II artifact-free projection overlaps can be produced with incorrectly reconstructed portions in the reconstructed image. Next, to validate the theory, the extended-type-II artifact-free overlaps were employed in designing the multiplexing multipinhole spiral orbit imaging systems with a baffle window. Numerical validations were performed via simulations, where the corresponding 1-pinhole nonmultiplexing reconstruction results were used as the benchmark for artifact-free reconstructions. The mean square error (MSE) was the metric used for comparisons of noise-free reconstructed images. Noisy reconstructions were also performed as part of the validations. Results: Simulation results show that for noise-free reconstructions, the MSEs of the reconstructed images of the artifact-free multiplexing systems are very similar to those of the corresponding 1-pinhole systems. No artifacts were observed in the reconstructed images. Therefore, the testing results for artifact-free multiplexing systems designed using the

  12. Selectively-etched nanochannel electrophoretic and electrochemical devices

    Science.gov (United States)

    Surh, Michael P [Livermore, CA; Wilson, William D [Pleasanton, CA; Barbee, Jr., Troy W.; Lane, Stephen M [Oakland, CA

    2006-06-27

    Nanochannel electrophoretic and electrochemical devices having selectively-etched nanolaminates located in the fluid transport channel. The normally flat surfaces of the nanolaminate having exposed conductive (metal) stripes are selectively-etched to form trenches and baffles. The modifications of the prior utilized flat exposed surfaces increase the amount of exposed metal to facilitate electrochemical redox reaction or control the exposure of the metal surfaces to analytes of large size. These etched areas variously increase the sensitivity of electrochemical detection devices to low concentrations of analyte, improve the plug flow characteristic of the channel, and allow additional discrimination of the colloidal particles during cyclic voltammetry.

  13. Research of nuclear power plant in-service maintenance based on virtual reality

    International Nuclear Information System (INIS)

    Wang Yong; Kuang Weijun

    2015-01-01

    This paper presents a method of constructing nuclear power plant in-service maintenance virtual simulation scene and virtual maintenance process. Taking air baffles dismantling process of CAP1400(China Advanced Passive 1400) nuclear power plant as an instance, this paper discusses ergonomics, space analysis, time assessment based on virtual reality in the process of in-service maintenance. It demonstrates the advantage of using VR technology to design and verify in-service maintenance process of nuclear power plant compared to the conventional way. (author)

  14. Samsung Galaxy S6 for dummies

    CERN Document Server

    Hughes, Bill

    2015-01-01

    Explore the capabilities of your Samsung Galaxy S 6 with this definitive guide! Learning to use a new phone can be both difficult and frustrating. With confusing documentation and baffling support, the references provided by phone manufacturers can be intimidating. Enter Samsung Galaxy S 6 For Dummies! This extensive yet practical guide walks you through the most useful features of your new Samsung Galaxy S 6-and it shows you all the best tricks to getting the most out of your device. With an accessible and fun, yet informative writing style, this is a text that you'll refer to again and agai

  15. Thermal hydraulic characteristics of a double-walled tube advanced nuclear steam generator

    International Nuclear Information System (INIS)

    Cho, S.M.; Seltzer, A.H.

    1989-01-01

    In this paper the thermal hydraulic characteristics of double-walled tube steam generator designed for sodium-cooled nuclear reactors are presented. The double-walled tube construction, along with double-barrier welds for tube-to-tubesheet joints, virtually eliminates the probability of heat transfer tube failure. Considerations are given to the use of the internal core tube, helical vane swirl generator, external protector tube, and variably perforated flow baffles to improve thermal and hydraulic performance of the steam generator. These thermal hydraulic design features with a particular reference to a 432 MW PRISM steam generator are discussed

  16. An introduction to recombination and linkage analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mcpeek, M.S. [Univ. of Chicago, IL (United States)

    1996-12-31

    With a garden as his laboratory, Mendel was able to discern basic probabilistic laws of heredity. Although it first appeared as a baffling exception to one of Mendel`s principles, the phenomenon of variable linkage between characters was soon recognized to be a powerful tool in the process of chromosome mapping and location of genes of interest. In this introduction, we first describe Mendel`s work and the subsequent discovery of linkage. Next we describe the apparent cause of variable linkage, namely recombination, and we introduce linkage analysis. 33 refs., 1 fig., 2 tabs.

  17. The geometric topology of 3-manifolds

    CERN Document Server

    Bing, R H

    1983-01-01

    This book belongs in both graduate and undergraduate libraries as a useful reference for students and researchers in topology. It is directed toward mathematicians interested in geometry who have had at least a beginning course in topology. It should provide the reader with a better understanding of the physical properties of Euclidean 3-space-the space in which we presume we live. The reader should learn of some unsolved problems that continue to baffle reseachers. The most profound result in the volume is the side approximation theorem. However, some of the preliminary results and some of th

  18. Characteristics of various confinement regimes obtained with EC and LH heating on the TdeV tokamak

    International Nuclear Information System (INIS)

    Pacher, G.W.; Decoste, R.; Demers, Y.

    1999-01-01

    Steady-state H-modes in type III ELM regime on TdeV with electron cyclotron and lower hybrid heating are investigated with respect to lower hybrid wave coupling, threshold power, helium pumping and separation between separatrix and surrounding structures. Energy confinement is found to improve as the distance between separatrix and divertor baffle is reduced. With off-axis EC heating, reduced particle transport is observed inside the deposition zone, but no energy transport barrier is obtained. New measurements on compact toroid fuelling are reported which indicate that further optimization of the injector is required. (author)

  19. Characteristics of various confinement regimes obtained with EC and LH heating on the TdeV tokamak

    International Nuclear Information System (INIS)

    Pacher, G.W.; Decoste, R.; Demers, Y.

    2001-01-01

    Steady-state H-modes in type III ELM regime on TdeV with electron cyclotron and lower hybrid heating are investigated with respect to lower hybrid wave coupling, threshold power, helium pumping and separation between separatrix and surrounding structures. Energy confinement is found to improve as the distance between separatrix and divertor baffle is reduced. With off-axis EC heating, reduced particle transport is observed inside the deposition zone, but no energy transport barrier is obtained. New measurements on compact toroid fuelling are reported which indicate that further optimization of the injector is required. (author)

  20. Evaluation of insulation materials and composites for use in a nuclear radiation environment, phase 2

    Science.gov (United States)

    Westerheide, D. E.; Carter, H. G.; Erickson, R. C.; Kerlin, E. E.

    1972-01-01

    The nuclear heating of the propellant in all of the four baseline RNS configurations studied was much lower than that of the nuclear flight module configuration with the 5000-MW NERVA analyzed previously. Although the nuclear heating has been reduced, the effect of nuclear heating on the propellant as well as the effect of nuclear heating on internal structures such as antivortex baffles, screens, and sump components cannot be neglected. In addition, it was found that the present analytical precedures were not able to predict boundary layer initiation and breakoff points with the accuracy necessary to predict propellant thermodynamic nonequilibrium (stratification) and/or mixing.

  1. Heat Losses from a Breathing System with a Heated-water Humidifier

    Science.gov (United States)

    Lunn, J. N.; Mapleson, W. W.; Hillard, E. K.

    1971-01-01

    Air was “breathed” in the laboratory through a heated-water humidifier and a breathing tube. Several different humidifiers and tubes were used. The temperature rise of the air on passing through the humidifier and the temperature drop on passing through the tube were measured. Both were dependent on ventilation. Insulating the tube and humidifier together with the insertion of baffles in the latter reduced the rise and fall and their dependence on ventilation. With suitable design the dependence on ventilation and the need to use high water temperatures could be greatly reduced. In addition, a thermostat with a reduced dead zone is needed. PMID:5289685

  2. Humidifier fever 1

    Science.gov (United States)

    1977-01-01

    MRC Symposium (1977).Thorax, 32, 653-663. Humidifier fever. In enclosed environments, it may be necessary to regulate temperature, ventilation, and humidity to maintain comfortable working conditions. Several systems can be used although in terms of installation and running costs a simple radiator system is far more economical than air conditioning with complete temperature and humidity control. Humidity control requires the introduction of water into a moving current of air, and in such a system baffle plates are often used to eliminate large droplets; also any unused water is usually recirculated. Organic dust drawn into the system and settling on the baffle plates and in the mixing chamber may be utilised by micro-organisms introduced from the atmosphere and from the water supply, and a biomass builds up. Microbial material is then voided into the working atmosphere by the ventilation system. Under appropriate exposure conditions susceptible individuals may succumb to an episode of humidifier fever, an influenza-like illness with pyrexia and malaise as the main symptoms, but cough, chest tightness, dyspnoea and weight loss may also be seen. The episodes usually occur after absence from work for a few days and have been termed `Monday sickness'. Individuals are often able to return to work the next day and appear refractory to further exposure. The disease is of the winter months probably due to the larger amount (up to 90%) of fresh air drawn into the humidifier during the summer. In the blood of exposed subjects precipitins are usually present to extracts of baffle plate material and recirculating water although they are not necessarily indicative of disease. Skin tests may be positive and inhalation challenge has reproduced the disease in susceptible individuals. Many organisms may be isolated from baffle plates and recirculating water but only amoeba extracts have produced consistently positive reactions with sera from affected individuals. Remedial actions

  3. Grammar in Art

    OpenAIRE

    Segel, Edward; Boroditsky, Lera

    2011-01-01

    Roman Jakobson (1959) reports: The Russian painter Repin was baffled as to why Sin had been depicted as a woman by German artists: he did not realize that sin is feminine in German (die Sünde), but masculine in Russian (грех). Does the grammatical gender of nouns in an artist’s native language indeed predict the gender of personifications in art? In this paper we analyzed works in the ARTstor database (a digital art library containing over a million images) to measure this correspondenc...

  4. Internal dust recirculation system for a fluidized bed heat exchanger

    Science.gov (United States)

    Gamble, Robert L.; Garcia-Mallol, Juan A.

    1981-01-01

    A fluidized bed heat exchanger in which air is passed through a bed of particulate material containing fuel disposed in a housing. A steam/water natural circulation system is provided in a heat exchange relation to the bed and includes a steam drum disposed adjacent the bed and a tube bank extending between the steam drum and a water drum. The tube bank is located in the path of the effluent gases exiting from the bed and a baffle system is provided to separate the solid particulate matter from the effluent gases. The particulate matter is collected and injected back into the fluidized bed.

  5. Approximate albedo boundary conditions for energy multigroup X,Y-geometry discrete ordinates nuclear global calculations

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Davi J.M.; Nunes, Carlos E.A.; Alves Filho, Hermes; Barros, Ricardo C., E-mail: davijmsilva@yahoo.com.br, E-mail: ceanunes@yahoo.com.br, E-mail: rcbarros@pq.cnpq.br [Secretaria Municipal de Educacao de Itaborai, RJ (Brazil); Universidade Estacio de Sa (UNESA), Rio de Janeiro, RJ (Brazil); Universidade do Estado do Rio de Janeiro (UERJ), Novra Friburgo, RJ (Brazil). Instituto Politecnico. Departamento de Modelagem Computacional

    2017-11-01

    Discussed here is the accuracy of approximate albedo boundary conditions for energy multigroup discrete ordinates (S{sub N}) eigenvalue problems in two-dimensional rectangular geometry for criticality calculations in neutron fission reacting systems, such as nuclear reactors. The multigroup (S{sub N}) albedo matrix substitutes approximately the non-multiplying media around the core, e.g., baffle and reflector, as we neglect the transverse leakage terms within these non-multiplying regions. Numerical results to a typical model problem are given to illustrate the accuracy versus the computer running time. (author)

  6. Sintering of beryllium oxide with 3-4 per cent elemental boron

    International Nuclear Information System (INIS)

    Pointud, R.; Rispal, Ch.; Le Garec, M.

    1958-01-01

    In order to manufacture a baffle absorbing neutrons of various energies, there was developed or mixture of a slower and an absorber. It is made by hot pressing impure beryllium containing boron carbide. The dense briquette has 100 x 100 x 50 mm and is machined on all her faces. She is of 2,85 density and about 3 to 4 per cent porosity, according to 5 per cent of boron. Difference of boron amount is lower than ten per cent between any two points of the briquette. (author) [fr

  7. Soil separator and sampler and method of sampling

    Science.gov (United States)

    O'Brien, Barry H [Idaho Falls, ID; Ritter, Paul D [Idaho Falls, ID

    2010-02-16

    A soil sampler includes a fluidized bed for receiving a soil sample. The fluidized bed may be in communication with a vacuum for drawing air through the fluidized bed and suspending particulate matter of the soil sample in the air. In a method of sampling, the air may be drawn across a filter, separating the particulate matter. Optionally, a baffle or a cyclone may be included within the fluidized bed for disentrainment, or dedusting, so only the finest particulate matter, including asbestos, will be trapped on the filter. The filter may be removable, and may be tested to determine the content of asbestos and other hazardous particulate matter in the soil sample.

  8. 金属光造形複合加工金型を用いた射出成形サイクルタイムの短縮

    OpenAIRE

    米山, 猛; 香川, 博之; 末廣, 栄覚; 阿部, 諭; 宮丸, 充

    2007-01-01

    By composing a cooling channel just near the mold surface using the milling-combined laser metal sintering method, cooling during injection is promoted and the cooling time is reduced. In order to evaluate this effect, a cone with ribs inside the upper part is picked up. A spiral-cooling channel is fabricated along the side surface of the mold core and also between the ribs in the upper part. To compare with this, a steel mold with machined baffle channels was made. The diameter of the upper ...

  9. LARGE EDDY SIMULATIONS OF THE TURBULENT FLOW IN A STIRRED TANK

    DEFF Research Database (Denmark)

    Fan, Jianhua; Wang, Yundong; Fei, Weiyang

    more computational time and computer memory. The results of the present work help to give deep understanding to the mixing mechanisms of the mechanically agitated tank, and can be used as guidance for future development of engineering tools for the design and scale-up of the stirred tank.......Computational fluid dynamics (CFD) simulations of the fluid flow in a baffled, stirred tank with a single Rushton turbine are performed. The simulations are carried out on the “Shengcao-21C” supercomputer via commercial CFD software CFX5, using k-ε and large eddy simulation (LES) turbulence model...

  10. LARGE EDDY SIMULATIONS OF THE TURBULENT FLOW IN A STIRRED TANK

    DEFF Research Database (Denmark)

    Fan, Jianhua; Wang, Yundong; Fei, Weiyang

    2005-01-01

    more computational time and computer memory. The results of the present work help to give deep understanding to the mixing mechanisms of the mechanically agitated tank, and can be used as guidance for future development of engineering tools for the design and scale-up of the stirred tank.......Computational fluid dynamics (CFD) simulations of the fluid flow in a baffled, stirred tank with a single Rushton turbine are performed. The simulations are carried out on the “Shengcao-21C” supercomputer via commercial CFD software CFX5, using k-ε and large eddy simulation (LES) turbulence model...

  11. Narrative Accounting Practices in Indonesia Companies

    Directory of Open Access Journals (Sweden)

    Inten Meutia

    2017-05-01

    Full Text Available This research aimed to reveal creative accounting practices in the form of narrative accounting occuring in companies in Indonesia. Using content analysis, this research analyzed the management discussion and analysis section in the annual report on the group of companies whose performance had increased and declined in several companies listed on the Indonesian Stock Exchange. This research finds that the narrative accounting practices are applied in these companies. The four methods of accounting narratives are found in both groups of companies. There are stressing the positive and downplaying the negative, baffling the readers, differential reporting, and attribution.

  12. Quantum Einstein, Bohr and the great debate about the nature of reality

    CERN Document Server

    Kumar, Manjit

    2008-01-01

    For most people, quantum theory is a byword for mysterious, impenetrable science. And yet for many years it was equally baffling for scientists themselves. Manjit Kumar gives a dramatic and superbly-written history of this fundamental scientific revolution, and the divisive debate at its heart.  For 60 years most physicists believed that quantum theory denied the very existence of reality itself. Yet Kumar shows how the golden age of physics ignited the greatest intellectual debate of the twentieth century.  Quantum sets the science in the context of the great upheavals of the modern age. In 1

  13. Sun Coke Company responds to coke demand

    Energy Technology Data Exchange (ETDEWEB)

    Barkdoll, M. [Sun Coke Company, Knoxville, TN (US)

    2004-07-01

    A set of 28 slides/overheads outline in words and photographs recent developments with which Sun Coke is involved. These include a update on the Jewell Coke Plant in Vansant, VA, USA and on the Indiana Habor Coke Company plant in East Chicago, IN, USA, news on the construction of a coking plant at Haverhill, OH, USA and of Sun Coke Tubarao in Vitoria, Brazil, and of proposed projects at Haverhill and at Port Talbot, Wales, UK. Technology updates by Sun Coke are described. These include flue gas sharing, automatic door latches, charging emission control, a high performance quench tower baffle system and a flat push hot car.

  14. Three-dimensional thermal-hydraulic calculations to support recirculating steam generator design

    International Nuclear Information System (INIS)

    Carlucci, L.N.

    1987-01-01

    This paper describes a number of applications of the THIRST thermal-hydraulics code to help resolve potential performance and reliability problems related to flow and energy maldistributions on the shell-side of recirculating steam generators. The applications considered are: flow-induced vibration of U-bend tubes subjected to non-uniform two-phase cross-flow, optimization of flow distribution baffle designs to maximize flow penetration of the tube bundle above the tubesheet and assessment of non-uniform steam-water separator loadings

  15. Closed circuit steam cooled turbine shroud and method for steam cooling turbine shroud

    Science.gov (United States)

    Burdgick, Steven Sebastian; Sexton, Brendan Francis; Kellock, Iain Robertson

    2002-01-01

    A turbine shroud cooling cavity is partitioned to define a plurality of cooling chambers for sequentially receiving cooling steam and impingement cooling of the radially inner wall of the shoud. An impingement baffle is provided in each cooling chamber for receiving the cooling media from a cooling media inlet in the case of the first chamber or from the immediately upstream chamber in the case of the second through fourth chambers and includes a plurality of impingement holes for effecting the impingement cooling of the shroud inner wall.

  16. Implantation, evaluation and improvement of the diffusion code package developed by the RIS0 Research Center

    International Nuclear Information System (INIS)

    Koide, M.C.M.

    1983-01-01

    The evaluation and improvement of the diffusion code package developed by the RIS0 Research Center of Denmark have been performed. The improvements made in the package consisted in the presentation of their manuals. In order to reduce the process time of the codes an analitical boundary condition capable of representing the effects of the baffle and the reflector on the flux distribution has been calculated. Such boundary condition was obtained using a one-dimensional medium in the framework of the two group diffusion theory. The results showed that the application of this boundary condition produces very accurate results and an appreciable economy of processing time. (author) [pt

  17. The acoustic power of a vibrating clamped circular plate revisited in the wide low frequency range using expansion into the radial polynomials.

    Science.gov (United States)

    Rdzanek, Wojciech P

    2016-06-01

    This study deals with the classical problem of sound radiation of an excited clamped circular plate embedded into a flat rigid baffle. The system of the two coupled differential equations is solved, one for the excited and damped vibrations of the plate and the other one-the Helmholtz equation. An approach using the expansion into radial polynomials leads to results for the modal impedance coefficients useful for a comprehensive numerical analysis of sound radiation. The results obtained are accurate and efficient in a wide low frequency range and can easily be adopted for a simply supported circular plate. The fluid loading is included providing accurate results in resonance.

  18. Cultivation conditions and the diffusion of oxygen into culture media: the rationale for the flask-to-medium ratio in microbiology.

    Science.gov (United States)

    Somerville, Greg A; Proctor, Richard A

    2013-01-16

    Bacterial cultivation requires consideration of three things: The bacterial strain, cultivation medium, and cultivation conditions. Most microbiologists dutifully report their choice of strains and cultivation media in manuscripts; however, these same microbiologists often overlook reporting cultivation conditions. Without this information, it is difficult to determine if cultures were grown aerobically, microaerobically, or anaerobically. To cultivate bacteria aerobically, it is necessary to understand that oxygen does not readily diffuse into culture media; it needs help to get in. Microbiologists can do this by altering the flask-to-medium ratio, rpm of agitation, and/or the concentration of atmospheric oxygen, or by using baffled flasks.

  19. Conceptual design study of the hylife lithium fall laser fusion chamber. FY 1979 annual report

    Energy Technology Data Exchange (ETDEWEB)

    1979-11-30

    In FY 1979, the basic configuration of FY 1978 was used as a reference point. Many studies were then made to either generate more design information concerning this design or to produce new concepts that would lead to a superior configuration. Among these activities were a detailed weight analysis, an assembly sequence, a chamber vibration analysis, a splash baffle stress study, and an analysis of first wall thermal stresses. Then some new concepts were introduced that pertained to the first wall, the lithium inlet nozzle, the chamber supports, the inlet piping, and pressure vessel.

  20. Sensitivity to plant modelling uncertainties in optimal feedback control of sound radiation from a panel

    DEFF Research Database (Denmark)

    Mørkholt, Jakob

    1997-01-01

    Optimal feedback control of broadband sound radiation from a rectangular baffled panel has been investigated through computer simulations. Special emphasis has been put on the sensitivity of the optimal feedback control to uncertainties in the modelling of the system under control.A model...... in terms of a set of radiation filters modelling the radiation dynamics.Linear quadratic feedback control applied to the panel in order to minimise the radiated sound power has then been simulated. The sensitivity of the model based controller to modelling uncertainties when using feedback from actual...

  1. Suppressor for reducing the muzzle blast and flash of a firearm

    Science.gov (United States)

    Klett, James W

    2014-09-30

    Disclosed are several examples of apparatuses for suppressing the blast and flash produced as a projectile is expelled by gases from a firearm. In some examples, gases are diverted away from the central chamber to an expansion chamber by baffles. The gases are absorbed by the expansion chamber and desorbed slowly, thus decreasing pressure and increasing residence time of the gases. In other examples, the gases impinge against a plurality of rods before expanding through passages between the rods to decrease the pressure and increase the residence time of the gases.

  2. Suppressors made from intermetallic materials

    Science.gov (United States)

    Klett, James W; Muth, Thomas R; Cler, Dan L

    2014-11-04

    Disclosed are several examples of apparatuses for suppressing the blast and flash produced as a projectile is expelled by gases from a firearm. In some examples, gases are diverted away from the central chamber to an expansion chamber by baffles. The gases are absorbed by the expansion chamber and desorbed slowly, thus decreasing pressure and increasing residence time of the gases. In other examples, the gases impinge against a plurality of rods before expanding through passages between the rods to decrease the pressure and increase the residence time of the gases. These and other exemplary suppressors are made from an intermetallic material composition for enhanced strength and oxidation resistance at high operational temperatures.

  3. Predicted and measured velocity distribution in a model heat exchanger

    International Nuclear Information System (INIS)

    Rhodes, D.B.; Carlucci, L.N.

    1984-01-01

    This paper presents a comparison between numerical predictions, using the porous media concept, and measurements of the two-dimensional isothermal shell-side velocity distributions in a model heat exchanger. Computations and measurements were done with and without tubes present in the model. The effect of tube-to-baffle leakage was also investigated. The comparison was made to validate certain porous media concepts used in a computer code being developed to predict the detailed shell-side flow in a wide range of shell-and-tube heat exchanger geometries

  4. Flight solar calibrations using the Mirror Attenuator Mosaic (MAM): Low scattering mirror

    Science.gov (United States)

    Lee, Robert B., III

    1992-01-01

    Measurements of solar radiances reflected from the mirror attenuator mosaic (MAM) were used to calibrate the shortwave portions of the Earth Radiation Budget Experiment (ERBE) thermistor bolometer scanning radiometers. The MAM is basically a low scattering mirror which has been used to attenuate and reflect solar radiation into the fields of view for the broadband shortwave (0.2 to 5 micrometers) and total (0.2 to 50.0+ micrometers) ERBE scanning radiometers. The MAM assembly consists of a tightly packed array of aluminum, 0.3175-cm diameter concave spherical mirrors and field of view limiting baffles. The spherical mirrors are masked by a copper plate, electro-plated with black chrome. Perforations (0.14 centimeter in diameter) in the copper plate serve as apertures for the mirrors. Black anodized aluminum baffles limit the MAM clear field of view to 7.1 degrees. The MAM assemblies are located on the Earth Radiation Budget Satellite (ERBS) and on the National Oceanic and Atmospheric Administration NOAA-9 and NOAA-10 spacecraft. The 1984-1985 ERBS and 1985-1986 NOAA-9 solar calibration datasets are presented. Analyses of the calibrations indicate that the MAM exhibited no detectable degradation in its reflectance properties and that the gains of the shortwave scanners did not change. The stability of the shortwave radiometers indicates that the transmission of the Suprasil W1 filters did not degrade detectably when exposed to Earth/atmosphere-reflected solar radiation.

  5. Tunable Fano Resonance in Asymmetric MIM Waveguide Structure.

    Science.gov (United States)

    Zhao, Xuefeng; Zhang, Zhidong; Yan, Shubin

    2017-06-25

    A plasmonic waveguide coupled system that uses a metal-insulator-metal (MIM) waveguide with two silver baffles and a coupled ring cavity is proposed in this study. The transmission properties of the plasmonic system were investigated using the finite element method. The simulation results show a Fano profile in the transmission spectrum, which was caused by the interaction of the broadband resonance of the Fabry-Perot (F-P) cavity and the narrow band resonance of the ring cavity. The Fabry-Perot (F-P) cavity in this case was formed by two silver baffles dividing the MIM waveguide. The maximum sensitivity of 718 nm/RIU and the maximum figure of merit of 4354 were achieved. Furthermore, the effects of the structural parameters of the F-P cavity and the ring cavity on the transmission properties of the plasmonic system were analyzed. The results can provide a guide for designing highly sensitive on-chip sensors based on surface plasmon polaritons.

  6. User's manual for rocket combustor interactive design (ROCCID) and analysis computer program. Volume 2: Appendixes A-K

    Science.gov (United States)

    Muss, J. A.; Nguyen, T. V.; Johnson, C. W.

    1991-01-01

    The appendices A-K to the user's manual for the rocket combustor interactive design (ROCCID) computer program are presented. This includes installation instructions, flow charts, subroutine model documentation, and sample output files. The ROCCID program, written in Fortran 77, provides a standardized methodology using state of the art codes and procedures for the analysis of a liquid rocket engine combustor's steady state combustion performance and combustion stability. The ROCCID is currently capable of analyzing mixed element injector patterns containing impinging like doublet or unlike triplet, showerhead, shear coaxial and swirl coaxial elements as long as only one element type exists in each injector core, baffle, or barrier zone. Real propellant properties of oxygen, hydrogen, methane, propane, and RP-1 are included in ROCCID. The properties of other propellants can be easily added. The analysis models in ROCCID can account for the influences of acoustic cavities, helmholtz resonators, and radial thrust chamber baffles on combustion stability. ROCCID also contains the logic to interactively create a combustor design which meets input performance and stability goals. A preliminary design results from the application of historical correlations to the input design requirements. The steady state performance and combustion stability of this design is evaluated using the analysis models, and ROCCID guides the user as to the design changes required to satisfy the user's performance and stability goals, including the design of stability aids. Output from ROCCID includes a formatted input file for the standardized JANNAF engine performance prediction procedure.

  7. Mass Transfer Coefficientin Stirred Tank for p -Cresol Extraction Process from Coal Tar

    International Nuclear Information System (INIS)

    Fardhyanti, D S; Tyaningsih, D S; Afifah, S N

    2017-01-01

    Indonesia is a country that has a lot of coal resources. The Indonesian coal has a low caloric value. Pyrolysis is one of the process to increase the caloric value. One of the by-product of the pyrolysis process is coal tar. It contains a lot of aliphatic or aromatic compounds such as p -cresol (11% v/v). It is widely used as a disinfectant. Extractionof p -Cresol increases the economic value of waste of coal. The aim of this research isto study about mass tranfer coefficient in the baffled stirred tank for p -Cresolextraction from coal tar. Mass transfer coefficient is useful for design and scale up of industrial equipment. Extraction is conducted in the baffled stirred tank equipped with a four-bladed axial impeller placed vertically in the vessel. Sample for each time processing (5, 10, 15, 20, 25 and 30minutes) was poured into a separating funnel, settled for an hour and separated into two phases. Then the two phases were weighed. The extract phases and raffinate phases were analyzed by Spectronic UV-Vis. The result showed that mixing speed of p -Cresol extraction increasesthe yield of p -Cresol and the mass transfer coefficient. The highest yield of p -Cresol is 49.32% and the highest mass transfer coefficient is 4.757 x 10 -6 kg/m 2 s. (paper)

  8. Mass Transfer Coefficientin Stirred Tank for p-Cresol Extraction Process from Coal Tar

    Science.gov (United States)

    Fardhyanti, D. S.; Tyaningsih, D. S.; Afifah, S. N.

    2017-04-01

    Indonesia is a country that has a lot of coal resources. The Indonesian coal has a low caloric value. Pyrolysis is one of the process to increase the caloric value. One of the by-product of the pyrolysis process is coal tar. It contains a lot of aliphatic or aromatic compounds such asp-cresol (11% v/v). It is widely used as a disinfectant. Extractionof p-Cresol increases the economic value of waste of coal. The aim of this research isto study about mass tranfer coefficient in the baffled stirred tank for p-Cresolextraction from coal tar. Mass transfer coefficient is useful for design and scale up of industrial equipment. Extraction is conducted inthe baffled stirred tank equipped with a four-bladed axial impeller placed vertically in the vessel. Sample for each time processing (5, 10, 15, 20, 25 and 30minutes) was poured into a separating funnel, settled for an hour and separated into two phases. Then the two phases were weighed. The extract phases and raffinate phases were analyzed by Spectronic UV-Vis. The result showed that mixing speed of p-Cresol extraction increasesthe yield of p-Cresol and the mass transfer coefficient. The highest yield of p-Cresol is 49.32% and the highest mass transfer coefficient is 4.757 x 10-6kg/m2s.

  9. A star tracker insensitive to stray light generated by radiation sources close to the field of view

    Science.gov (United States)

    Romoli, A.; Gambicorti, L.; Simonetti, F.; Zuccaro Marchi, A.

    2017-11-01

    Aim of this work is to propose an innovative star tracker, practically insensitive to the radiation coming from the sun or from other strong planetary sources out of (but near) the Field of View. These sources need to be stopped in some way. The classical solution to reject the unwanted radiation is to place a shadow (or baffle) before the star tracker objective. The shadow size depends on the Field of View and on the minimum angle subtended by the source (i.e. the sun) with respect to the optical axis of the star tracker. The lower is this angle the larger is the shadow. Requests for star trackers able to work with the sun as close as possible to the Field of View are increasing, due to the need of maximum mission flexibility. The innovation of this proposed star tracker is conceived by using spatial filtering with a concept complementary to that of coronagraph for sun corona observation, allowing to drastically reduce the size of the shadow. It can also work close to antennas and other part of the platform, which, when illuminated by the sun, become secondary sources capable to blind the star tracker. This kind of accommodation offers three main advantages: no cumbersome shadows (baffle), maximum flexibility in terms of mission profile, less platform location constraints. This new star sensor concept, dated 2007, is now patent pending. Galileo Avionica (now Selex Galileo) is the owner of the patent.

  10. VUV Spectroscopy in DIII-D Divertor

    International Nuclear Information System (INIS)

    Alkesh Punjabi; Nelson Jalufka

    2004-01-01

    The research carried out on this grant was motivated by the high power emission from the CIV doublet at 155 nm in the DIII-D divertor and to study the characteristics of the radiative divertor. The radiative divertor is designed to reduce the heat load to the target plates of the divertor by reducing the energy in the divertor plasma using upstream scrape-off-layer (SOL) radiation. In some cases, particularly in Partially Detached Divertor (PDD) operations, this emission accounts for more than 50% of the total radiation from the divertor. In PDD operation, produced by neutral gas injection, the particle flow to the target plate and the divertor temperature are significantly reduced. A father motivation was to study the CIV emission distribution in the lower, open divertor and the upper baffled divertor. Two Vacuum Ultra Violet Tangential viewing Television cameras (VUV TTV) were constructed and installed in the upper, baffled and the lower, open divertor. The images recorded by these cameras were then inverted to produce two-dimensional distributions of CIV in the poloidal plane. Results obtained in the project are summarized in this report

  11. Final Technical Report for Grant DE-FG02-97ER54451

    International Nuclear Information System (INIS)

    Punjabi, A.; Jalufka, N.

    2004-01-01

    VUV ultraviolet spectroscopy in DIII-D Divertor. The research carried out on this grant was motivated by the high power emission from the CIV doublet at 155 nm in the DIII-D divertor and to study the characteristics of the radiative divertor. The radiative divertor is designed to reduce the heat load to the target plates of the divertor by reducing the energy in the divertor plasma using upstream scrape-off-layer (SOL) radiation. In some cases, particularly in Partially Detached Divertor (PDD) operations, this emission accounts for more than 50% of the total radiation from the divertor. In PDD operation, produced by neutral gas injection, the particle flow to the target plate and the divertor temperature are significantly reduced. A father motivation was to study the CIV emission distribution in the lower, open divertor and the upper baffled divertor. Two Vacuum Ultra Violet Tangential viewing Television cameras (VUV TTV) were constructed and installed in the upper, baffled and the lower, open divertor. The images recorded by these cameras were then inverted to produce two-dimensional distributions of CIV in the poloidal plane. Results obtained with these cameras are summarized

  12. Preliminary results of sedimentation study in SMART, Kg. Berembang holding pond

    International Nuclear Information System (INIS)

    Jeremy Andy Dominic; Wan Zakaria Wan Md Tahir; Lakam Mejus; Juhari Mohd Yusuf; Kamaruzaman Mohamad; Mod Omar Hassan

    2010-01-01

    Full text: Spatial variations of the sediment bulk density profile in the Storm water Management And Road Tunnel (SMART) holding pond were measured at every 20 metre intervals along six cross section lines with a total of 72 sampling points using a Cs-137 nuclear backscatter probe. The bulk density profile at each sampling points were vertically measured at every 2 inches increment in an upward direction. The thickness of the deposited sediment varies spatially with a gradual increase towards the centre of the holding pond. The highest sediment deposition areas are located near the baffle walls, the centre and the south east corner of the holding pond. The maximum thickness of the deposited sediment adjacent to the baffle walls is 22 inch and at both the centre and south east area are 18 inch. The sediment bulk density profile varies from 1,010 kg.m -3 to 1,400 kg.m -3 . Spatial density variations are in correlation with the active and inactive zone in the pond area. The potential of sediment deposition and consolidation process is higher in the inactive zone compare to the active zone, therefore the bulk density value the inactive zone is much higher. (author)

  13. Methods of testing HEPA filters with short upstream approaches

    International Nuclear Information System (INIS)

    Kirk, G.Q.; Childress, C.E.; Schmoyer, D.D.

    1989-01-01

    The design of an air cleaning system to be used in a high gamma radiation field presented unique problems for in-place Dioctyl phthalate (DOP) leak testing. The design required remotely changeable HEPA (High Efficiency Particulate Air) filters in a disposable, stainless steel housing, located underground in a stainless steel-lined concrete pit. The conventional approach of providing ten duct diameters of upstream mixing for the dispersion of the challenge aerosol was not a viable solution to the necessity of testing the second filter stage in the system. To establish aerosol (DOP) injection ports that could provide mixing in accordance with ANSI N510-80, a full-scale housing was built. The housing and components were built of Plexiglas to view the DOP streams. A series of tests was designed in which the following factors were varied: (1) aerosol distributors, (2) aerosol distributor locations, (3) baffle design, and (4) baffle location. DOP concentration measurements were taken immediately upstream of the filters. The uniformity score, as determined by ANSI N510-80, was defined as the larger of maximum minus average values of DOP concentration. Three tests met the uniformity score requirement of 0.20, but all three had ten duct diameters of upstream mixing. The type of aerosol distributor, duct length, and flow rate were found to most affect the uniformity score

  14. Development of small scale cell culture models for screening poloxamer 188 lot-to-lot variation.

    Science.gov (United States)

    Peng, Haofan; Hall, Kaitlyn M; Clayton, Blake; Wiltberger, Kelly; Hu, Weiwei; Hughes, Erik; Kane, John; Ney, Rachel; Ryll, Thomas

    2014-01-01

    Shear protectants such as poloxamer 188 play a critical role in protecting cells during cell culture bioprocessing. Lot-to-lot variation of poloxamer 188 was experienced during a routine technology transfer across sites of similar scale and equipment. Cell culture medium containing a specific poloxamer 188 lot resulted in an unusual drop in cell growth, viability, and titer during manufacturing runs. After switching poloxamer lots, culture performance returned to the expected level. In order to control the quality of poloxamer 188 and thus maintain better consistency in manufacturing, multiple small scale screening models were developed. Initially, a 5L bioreactor model was established to evaluate cell damage by high sparge rates with different poloxamer 188 lots. Subsequently, a more robust, simple, and efficient baffled shake flask model was developed. The baffled shake flask model can be performed in a high throughput manner to investigate the cell damage in a bubbling environment. The main cause of the poor performance was the loss of protection, rather than toxicity. It was also suggested that suspicious lots can be identified using different cell line and media. The screening methods provide easy, yet remarkable models for understanding and controlling cell damage due to raw material lot variation as well as studying the interaction between poloxamer 188 and cells. © 2014 American Institute of Chemical Engineers.

  15. Design of a dynamic sensor inspired by bat ears

    International Nuclear Information System (INIS)

    Müller, Rolf; Pannala, Mittu; Praveen K Reddy, O; Meymand, Sajjad Z

    2012-01-01

    In bats, the outer ear shapes act as beamforming baffles that create a spatial sensitivity pattern for the reception of the biosonar signals. Whereas technical receivers for wave-based signals usually have rigid geometries, the outer ears of some bat species, such as horseshoe bats, can undergo non-rigid deformations as a result of muscular actuation. It is hypothesized that these deformations provide the animals with a mechanism to adapt their spatial hearing sensitivity on short, sub-second time scales. This biological approach could be of interest to engineering as an inspiration for the design of beamforming devices that combine flexibility with parsimonious implementation. To explore this possibility, a biomimetic dynamic baffle was designed based on a simple shape overall geometry based on an average bat ear. This shape was augmented with three different biomimetic local shape features, a ridge on its exposed surface as well as a flap and an incision along its rim. Dynamic non-rigid deformations of the shape were accomplished through a simple actuation mechanism based on linear actuation inserted at a single point. Despite its simplicity, the prototype device was able to reproduce the dynamic functional characteristics that have been predicted for its biological paragon in a qualitative fashion. (paper)

  16. Optimization of flow control devices for a T-type five-strand billet caster tundish: water modeling and numerical simulation

    Directory of Open Access Journals (Sweden)

    Fei He

    2016-05-01

    Full Text Available The optimization of flow control devices (FCDs for a T-type five-strand billet caster tundish was carried out by water modeling and numerical simulation. In water modeling experiments, flow characteristics of the bare tundish and tundish configurations with designed U-type baffles and a round turbulence inhibitor were analyzed using residence time distribution (RTD curves. Mathematical models for liquid steel in the real plant tundish were established using the fluid dynamics software package Fluent. The flow field, the temperature field, and the RTD curves of liquid steel in the proposed tundish configurations were obtained. The results of numerical simulation and water modeling were validated with each other by the predicted and experimental RTD curves. The results of flow field and temperature field were used to reflect the actual state of a real plant tundish and to choose the optimal FCD. Finally, from the whole performance of the multi-strand tundish, the optimal scheme was determined by combining the results of water modeling and numerical simulation. With the optimal tundish equipped with U-type baffle with deflector holes and round turbulence inhibitor, not only was the flow characteristic of each strand improved, but also the difference of flow characteristics between multiple strands was smaller.

  17. Advancement in Mixing Hydrodynamics using Motionless Mixer

    Directory of Open Access Journals (Sweden)

    Mazhar Hussain

    2015-07-01

    Full Text Available A large number of scientists have been conducting research to improve the hydrodynamic characteristics of mixing of fluids. Out of these techniques, static mixing is adopted in this study to improve the mixing of fluids, which has a lead of negligible energy consumption in comparison with dynamic mixers. Air Water system have been cast-off for mixing in which reduction in pressure, energy consumed, bubble diameter and mass transfer rate was mainly taken into account to design the static mixer element. Five different types of elements (Baffle, Plate, Blade, Needle and Wheel were tested to observe and compare above mentioned hydrodynamic properties. Two point source characteristics i.e. reduction in pressure and bubble size, were carried out using Hg manometer and still photography respectively. Other nonpoint source characteristics (Energy depletion, rate of mixing were found to be directly influenced by these point source characteristics. From the experimentations baffle element catches more importance, in terms of less energy depletion, more mixing rate, when compared with the other elements tested. This element becomes also comparable with other elements renowned in literature.

  18. Validation Hydrodynamic Models of Three Topological Models of Secondary Facultative Ponds

    Directory of Open Access Journals (Sweden)

    Aponte-Reyes Alxander

    2014-10-01

    Full Text Available A methodology was developed to analyze boundary conditions, the size of the mesh and the turbulence of a mathematical model of CFD, which could explain hydrodynamic behavior on facultative stabilization ponds, FSP, built to pilot scale: conventional pond, CP, baffled pond, BP, and baffled-mesh pond, BMP. Models dispersion studies were performed in field for validation, taking samples into and out of the FSP, the information was used to carry out CFD model simulations of the three topologies. Evaluated mesh sizes ranged from 500,000 to 2,000,000 elements. The boundary condition in Pared surface-free slip showed good qualitative behavior and the turbulence model κ–ε Low Reynolds yielded good results. The biomass contained in LFS generates interference on dispersion studies and should be taken into account in assessing the CFD modeling, the tracer injection times, its concentration at the entrance, the effect of wind on CFD, and the flow models adopted as a basis for modeling are parameters to be taken into account for the CFD model validation and calibration.

  19. CATALYTIC RECOMBINER FOR A NUCLEAR REACTOR

    Science.gov (United States)

    King, L.D.P.

    1960-07-01

    A hydrogen-oxygen recombiner is described for use with water-boiler type reactors. The catalyst used is the wellknown platinized alumina, and the novelty lies in the structural arrangement used to prevent flashback through the gas input system. The recombiner is cylindrical, the gases at the input end being deflected by a baffle plate through a first flashback shield of steel shot into an annular passage adjacent to and extending the full length of the housing. Below the baffle plate the gases flow first through an outer annular array of alumina pellets which serve as a second flashback shield, a means of distributing the flowing gases evenly and as a means of reducing radiation losses to the walls. Thereafter the gases flow inio the centrally disposed catalyst bed where recombination is effected. The steam and uncombined gases flow into a centrally disposed cylindrical passage inside the catalyst bod and thereafter out through the exit port. A high rate of recombination is effected.

  20. User's manual for rocket combustor interactive design (ROCCID) and analysis computer program. Volume 1: User's manual

    Science.gov (United States)

    Muss, J. A.; Nguyen, T. V.; Johnson, C. W.

    1991-01-01

    The user's manual for the rocket combustor interactive design (ROCCID) computer program is presented. The program, written in Fortran 77, provides a standardized methodology using state of the art codes and procedures for the analysis of a liquid rocket engine combustor's steady state combustion performance and combustion stability. The ROCCID is currently capable of analyzing mixed element injector patterns containing impinging like doublet or unlike triplet, showerhead, shear coaxial, and swirl coaxial elements as long as only one element type exists in each injector core, baffle, or barrier zone. Real propellant properties of oxygen, hydrogen, methane, propane, and RP-1 are included in ROCCID. The properties of other propellants can easily be added. The analysis model in ROCCID can account for the influence of acoustic cavities, helmholtz resonators, and radial thrust chamber baffles on combustion stability. ROCCID also contains the logic to interactively create a combustor design which meets input performance and stability goals. A preliminary design results from the application of historical correlations to the input design requirements. The steady state performance and combustion stability of this design is evaluated using the analysis models, and ROCCID guides the user as to the design changes required to satisfy the user's performance and stability goals, including the design of stability aids. Output from ROCCID includes a formatted input file for the standardized JANNAF engine performance prediction procedure.

  1. Additive manufacturing of short and mixed fibre-reinforced polymer

    Energy Technology Data Exchange (ETDEWEB)

    Lewicki, James; Duoss, Eric B.; Rodriguez, Jennifer Nicole; Worsley, Marcus A.; King, Michael J.

    2018-01-09

    Additive manufacturing of a fiber-reinforced polymer (FRP) product using an additive manufacturing print head; a reservoir in the additive manufacturing print head; short carbon fibers in the reservoir, wherein the short carbon fibers are randomly aligned in the reservoir; an acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin in the reservoir, wherein the short carbon fibers are dispersed in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin; a tapered nozzle in the additive manufacturing print head operatively connected to the reservoir, the tapered nozzle produces an extruded material that forms the fiber-reinforced polymer product; baffles in the tapered nozzle that receive the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin with the short carbon fibers dispersed in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin; and a system for driving the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin with the short carbon fibers dispersed in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin from the reservoir through the tapered nozzle wherein the randomly aligned short carbon fibers in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin are aligned by the baffles and wherein the extruded material has the short carbon fibers aligned in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin that forms the fiber-reinforced polymer product.

  2. Cross-fault pressure depletion, Zechstein carbonate reservoir, Weser-Ems area, Northern German Gas Basin

    Energy Technology Data Exchange (ETDEWEB)

    Corona, F.V.; Brauckmann, F.; Beckmann, H.; Gobi, A.; Grassmann, S.; Neble, J.; Roettgen, K. [ExxonMobil Production Deutschland GmbH (EMPG), Hannover (Germany)

    2013-08-01

    A cross-fault pressure depletion study in Upper Permian Zechstein Ca2 carbonate reservoir was undertaken in the Weser-Ems area of the Northern German Gas Basin. The primary objectives are to develop a practical workflow to define cross-fault pressures scenarios for Zechstein Ca2 reservoir drillwells, to determine the key factors of cross-fault pressure behavior in this platform carbonate reservoir, and to translate the observed cross-fault pressure depletion to fault transmissibility for reservoir simulation models. Analysis of Zechstein Ca2 cross-fault pressures indicates that most Zechstein-cutting faults appear to act as fluid-flow baffles with some local occurrences of fault seal. Moreover, there appears to be distinct cross-fault baffling or pressure depletion trends that may be related to the extent of the separating fault or fault system, degree of reservoir flow-path tortuosity, and quality of reservoir juxtaposition. Based on the above observations, a three-part workflow was developed consisting of (1) careful interpretation and mapping of faults and fault networks, (2) analysis of reservoir juxtaposition and reservoir juxtaposition quality, and (3) application of the observed cross-fault pressure depletion trends. This approach is field-analog based, is practical, and is being used currently to provide reliable and supportable pressure prediction scenarios for subsequent Zechstein fault-bounded drill-well opportunities.

  3. Characterization of stirrers for screening studies of enzymatic biomass hydrolyses on a milliliter scale.

    Science.gov (United States)

    Riedlberger, Peter; Brüning, Stefanie; Weuster-Botz, Dirk

    2013-07-01

    The evaluation of mixing quality is an important factor for improving the geometry of stirred-tank reactors and impellers used in bioprocess engineering applications, such as the enzymatic hydrolysis of plant materials. Homogeneity depends on different factors, including the stirrer type and the reactor type (e.g., ratio of diameter/height, ratio of impeller tip diameter/reactor diameter) with or without baffles. This study compares two impellers for enzymatic hydrolysis of suspensions of biomass particles on a milliliter scale. Both impellers were derived from industrially relevant geometries, such as blade and grid stirrers, although the geometry of the second stirrer was slightly modified to an asymmetric shape. The stirrers were investigated with different stirrer-reactor configurations. This was done experimentally and with the aid of computational fluid dynamics. The flow field, mixing numbers, power characteristics and initial conversion rates of sugars were considered to compare the two stirrers. The simulated mixing numbers and power characteristics in baffled and unbaffled milliliter-scale reactors were found to be in good agreement with the measured mixing times and power consumption. The mixing numbers required to reach homogeneity were much higher for the symmetric impeller and remained at least twice as high as the mixing numbers required when using the asymmetric impeller. The highest initial sugar releases from milled corn stover suspensions were achieved with the asymmetric impeller shape. Regardless of the differences in the flow fields or mixing times, diverging enzymatic sugar releases could be confirmed for Newtonian media only.

  4. Scattered light characterization of FORTIS

    Science.gov (United States)

    McCandliss, Stephan R.; Carter, Anna; Redwine, Keith; Teste, Stephane; Pelton, Russell; Hagopian, John; Kutyrev, Alexander; Li, Mary J.; Moseley, S. Harvey

    2017-08-01

    We describe our efforts to build a Wide-Field Lyman alpha Geocoronal simulator (WFLaGs) for characterizing the end-to-end sensitivity of FORTIS (Far-UV Off Rowland-circle Telescope for Imaging and Spectroscopy) to scattered Lyman α emission from outside of the nominal (1/2 degree)2 field-of-view. WFLaGs is a 50 mm diameter F/1 aluminum parabolic collimator fed by a hollow cathode discharge lamp with a 80 mm clear MgF2 window housed in a vacuum skin. It creates emission over a 10 degree FOV. WFLaGS will allow us to validate and refine a recently developed scattered light model and verify our scatter light mitigation strategies, which will incorporate low scatter baffle materials, and possibly 3-d printed light traps, covering exposed scatter centers. We present measurements of scattering intensity of Lyman alpha as a function of angle with respect to the specular reflectance direction for several candidate baffle materials. Initial testing of WFLaGs will be described.

  5. Developing Ecological Models on Carbon and Nitrogen in Secondary Facultative Ponds

    Directory of Open Access Journals (Sweden)

    Aponte-Reyes Alexander

    2014-07-01

    Full Text Available Ecological models formulated for TOC, CO2, NH4+, NO3- and NTK, based in literature reviewed and field work were obtained monitoring three facultative secondary stabilization ponds, FSSP, pilots: conventional pond, CP, baffled pond, BP, and baffled-meshed pond, BMP. Models were sensitive to flow inlet, solar radiation, pH and oxygen content; the sensitive parameters in Carbon Model were KCOT Ba, umax Ba, umax Al, K1OX, VAl, R1DCH4, YBh. The sensitive parameters in the Nitrogen model were KCOT Ba, umax Ba, umax Al, VAl, KOPH, KOPA, r4An. The test t–paired showed a good simulating of Carbon model refers to TOC in FSSP; on the other side, the Nitrogen model showed a good simulating of NH4+. Different topological models modify ecosystem ecology forcing different transformation pathways of Nitrogen; equal transformations of the Carbon BMP topology could be achieved using lower volumes, however, a calibration for a new model would be required. Carbon and Nitrogen models developed could be coupled to hydrodynamics models for better modeling of FSSP.

  6. Low scatter edge blackening compounds for refractive optical elements

    International Nuclear Information System (INIS)

    Lewis, I.T.; Telkamp, A.R.; Ledebuhr, A.G.

    1989-01-01

    This paper reports on low scatter edge blackening compounds for refractive optical elements. Perkin-Elmer's Applied Optics Operation recently delivered several prototype wide-field-of-view (WFOV), F/2.8, 250 mm efl, near diffraction limited, concentric lenses toLawrence Livermore National Laboratory (LLNL). In these lenses, special attention was paid to reducing stray light to allow viewing of very dim objects. Because of the very large FOV, the use of a long baffle to eliminate direct illumination of lens edges was not practical. With the existing relatively short baffle design, one-bounce stray light paths off the element edges are possible. The scattering off the inside edges thus had to be kept to an absolute minimum. While common means for blackening the edges of optical elements are easy to apply and quite cost effective for normal lens assemblies, their blackening effect is limited by the Fresnel reflection due to the index of refraction mismatch at the glass boundary. At high angles of incidence, total internal reflection (TIR) might occur ruining the effect of the blackening process. An index-match absorbing medium applied to the edges of such elements is the most effective approach for reducing the amount of undesired light reflection or scattered off these edges. The presence of such a medium provides an extended path outside the glass boundary in which an absorptive non-scattering dye can be used to eliminate light that might otherwise have propagated to the focal plane

  7. Armour materials for the ITER plasma facing components

    International Nuclear Information System (INIS)

    Barabash, V.; Federici, G.; Matera, R.; Raffray, A.R.

    1999-01-01

    The selection of the armour materials for the plasma facing components (PFCs) of the international thermonuclear experimental reactor (ITER) is a trade-off between multiple requirements derived from the unique features of a burning fusion plasma environment. The factors that affect the selection come primarily from the requirements of plasma performance (e.g., minimise impurity contamination in the confined plasma), engineering integrity, component lifetime (e.g., withstand thermal stresses, acceptable erosion, etc.) and safety (minimise tritium and radioactive dust inventories). The current selection in ITER is to use beryllium on the first-wall, upper baffle and on the port limiter surfaces, carbon fibre composites near the strike points of the divertor vertical target and tungsten elsewhere in the divertor and lower baffle modules. This paper provides the background for this selection vis-a-vis the operating parameters expected during normal and off-normal conditions. The reasons for the selection of the specific grades of armour materials are also described. The effects of the neutron irradiation on the properties of Be, W and carbon fibre composites at the expected ITER conditions are briefly reviewed. Critical issues are discussed together with the necessary future R and D. (orig.)

  8. Armour Materials for the ITER Plasma Facing Components

    Science.gov (United States)

    Barabash, V.; Federici, G.; Matera, R.; Raffray, A. R.; ITER Home Teams,

    The selection of the armour materials for the Plasma Facing Components (PFCs) of the International Thermonuclear Experimental Reactor (ITER) is a trade-off between multiple requirements derived from the unique features of a burning fusion plasma environment. The factors that affect the selection come primarily from the requirements of plasma performance (e.g., minimise impurity contamination in the confined plasma), engineering integrity, component lifetime (e.g., withstand thermal stresses, acceptable erosion, etc.) and safety (minimise tritium and radioactive dust inventories). The current selection in ITER is to use beryllium on the first-wall, upper baffle and on the port limiter surfaces, carbon fibre composites near the strike points of the divertor vertical target and tungsten elsewhere in the divertor and lower baffle modules. This paper provides the background for this selection vis-à-vis the operating parameters expected during normal and off-normal conditions. The reasons for the selection of the specific grades of armour materials are also described. The effects of the neutron irradiation on the properties of Be, W and carbon fibre composites at the expected ITER conditions are briefly reviewed. Critical issues are discussed together with the necessary future R&D.

  9. Design and construction of a lithium vapor box divertor similarity experiment

    Science.gov (United States)

    Schwartz, J. A.; Cohen, R. A.; Emdee, E. D.; Jaworski, M. A.; Goldston, R. J.

    2017-10-01

    Future fusion devices will require handling extreme heat fluxes. The lithium vapor box divertor is a concept to manage this heat flux. The divertor plasma impinges on a dense cloud of lithium vapor, leading to volumetric cooling, radiation, and recombination. The vapor is localized by baffles and condensation on the divertor slot walls upstream of the target, limiting the lithium reaching the main chamber. A series of test stand experiments will study vapor confinement and plasma plugging in a simplified baffled-pipe geometry. A first experiment without plasma will validate a DSMC model for evaporation, flow, and condensation of lithium vapor. Three stainless steel cylindrical cans will be heated to 550C, 600C, and 650C respectively inside a vacuum chamber. Lithium flow will be measured by weighing the cans before and after heating and by calorimetry of the latent heat of the vapor. Progress on the experiment will be presented. This work supported by DOE Contract No. DE-AC02-09CH11466.

  10. "Sturdy as a house with four windows," the star tracker of the future

    Science.gov (United States)

    Duivenvoorde, Tom; Leijtens, Johan; van der Heide, Erik J.

    2017-11-01

    Ongoing miniaturization of spacecraft demands the reduction in size of Attitude and Orbit Control Systems (AOCS). Therefore TNO has created a new design of a multi aperture, high performance, and miniaturized star tracker. The innovative design incorporates the latest developments in camera technology, attitude calculation and mechanical design into a system with 5 arc seconds accuracy, making the system usable for many applications. In this paper the results are presented of the system design and analysis, as well as the performance predictions for the Multi Aperture Baffled Star Tracker (MABS). The highly integrated system consists of multiple apertures without the need for external baffles, resulting in major advantages in mass, volume, alignment with the spacecraft and relative aperture stability. In the analysis part of this paper, the thermal and mechanical stability are discussed. In the final part the simulation results will be described that have lead to the predicted accuracy of the star tracker system and a peek into the future of attitude sensors is given.

  11. Numerical exploration of non-axisymmetric divertor closure in the small angle slot (SAS) divertor at DIII-D

    Science.gov (United States)

    Frerichs, H.; Schmitz, O.; Covele, B.; Feng, Y.; Guo, H. Y.; Hill, D.

    2018-05-01

    Numerical simulations of toroidal asymmetries in a tightly baffled small angle slot (SAS) divertor on the DIII-D tokamak show that toroidal asymmetries in divertor closure result in (non-axisymmetric) local onset of detachment within a density window of 10-15% on top of the nominal threshold separatrix density. The SAS divertor is explored at DIII-D for improving access to cold, dissipative/detached divertor conditions. The narrow width of the slot divertor coupled with a small magnetic field line-to-target angle facilitates the buildup of neutral density, thereby increasing radiative and neutrals-related (atoms and molecules) losses in the divertor. Small changes in the strike point location can be expected to have a large impact on divertor conditions. The combination of misaligned slot structure and non-axisymmetric perturbations to the magnetic field configuration causes the strike point to move along the divertor target plate, possibly leaving the divertor slot at some locations. The latter extreme case essentially introduces an opening in the divertor slot from where recycling neutrals can easily escape, and thereby degrade the performance of the slot divertor. Such a strike point dislocation is approximated by a finite gap in the divertor baffle for which 3D edge plasma and neutral gas simulations are performed with the EMC3-EIRENE code.

  12. Internal erosion rates of a 10-kW xenon ion thruster

    Science.gov (United States)

    Rawlin, Vincent K.

    1988-01-01

    A 30 cm diameter divergent magnetic field ion thruster, developed for mercury operation at 2.7 kW, was modified and operated with xenon propellant at a power level of 10 kW for 567 h to evaluate thruster performance and lifetime. The major differences between this thruster and its baseline configuration were elimination of the three mercury vaporizers, use of a main discharge cathode with a larger orifice, reduction in discharge baffle diameter, and use of an ion accelerating system with larger acceleration grid holes. Grid thickness measurement uncertainties, combined with estimates of the effects of reactive residual facility background gases gave a minimum screen grid lifetime of 7000 h. Discharge cathode orifice erosion rates were measured with three different cathodes with different initial orifice diameters. Three potential problems were identified during the wear test: the upstream side of the discharge baffle eroded at an unacceptable rate; two of the main cathode tubes experienced oxidation, deformation, and failure; and the accelerator grid impingement current was more than an order of magnitude higher than that of the baseline mercury thruster. The charge exchange ion eroison was not quantified in this test. There were no measurable changes in the accelerator grid thickness or the accelerator grid hole diameters.

  13. [A novel flat plate photobioreactor for microalgae cultivation].

    Science.gov (United States)

    Zhang, Qinghua; Yan, Chenghu; Xue, Shengzhang; Wu, Xia; Wang, Zhihui; Cong, Wei

    2015-02-01

    Flashing light effect on microalgae could significantly improve the light efficiency and biomass productivity of microalgae. In this paper, the baffles were introduced into the traditional flat plate photobioreactor so as to enhance the flashing light effect of microalgae. Making Chlorella sp. as the model microalgae, the effect of light intensity and inlet velocity on the biomass concentration of Chlorella sp. and light efficiency were evaluated. The results showed that, when the inlet velocity was 0.16 m/s, with the increase of light intensity, the cell dry weight of Chlorella sp. increased and light efficiency decreased. With increasing the inlet velocity, the cell dry weight of Chlorella sp. and light efficiency both increased under the condition of 500 μmol/(m2 x s) light intensity. The cell dry weight of Chlorella sp. cultivated in the novel flat plate photobioreactor was 39.23% higher than that of the traditional one, which showed that the flashing light effect of microalgae could be improved in the flat plate photobioreactor with inclined baffles built-in.

  14. Development of a low temperature solid HIP process for joining CFC monoblocks onto CuCrZr tubes

    International Nuclear Information System (INIS)

    Planksteiner, A.; Schedler, B.; Krismer, R.; Rainer, F.

    2001-01-01

    A low temperature solid HIP process is developed for ITER Divertor Baffle components in order to join AMC CFC monoblocks onto CuCrZr tubes without overaging. For the fabrication solution annealed cold worked CuCrZr-tubes age-hardened during the hot isostatic pressing (HIP) process are joined to the back-casted (AMC) WHC copper ring of the WC monoblock. The process relevant influence parameters (clearance between components, thickness of can, maximum HIP pressure, pressure and temperature history in time) and quality relevant parameters (contact pressure at HIP interface, stresses in the WC body) are determined in a brainstorming. By using the design of experiments (DoE) software a number of parameter sets are defined that act as input for the process simulation via finite element method (FEM) based models each of which representing an individual parameter set. The values for the quality relevant parameters calculated this way are then evaluated with the DoE software in order to detect the functional dependencies between them. An optimum set of parameters is detected and has been verified successfully in a manufacturing process of several prototype components as well as full-scale components for the ITER Divertor Baffle. (author)

  15. Dilatant shear band formation and diagenesis in calcareous, arkosic sandstones, Vienna Basin (Austria)

    Science.gov (United States)

    Lommatzsch, Marco; Exner, Ulrike; Gier, Susanne; Grasemann, Bernhard

    2015-01-01

    The present study examines deformation bands in calcareous arkosic sands. The investigated units can be considered as an equivalent to the Matzen field in the Vienna Basin (Austria), which is one of the most productive oil reservoirs in central Europe. The outcrop exposes carbonate-free and carbonatic sediments of Badenian age separated by a normal fault. Carbonatic sediments in the hanging wall of the normal fault develop dilation bands with minor shear displacements (< 2 mm), whereas carbonate-free sediments in the footwall develop cataclastic shear bands with up to 70 cm displacement. The cataclastic shear bands show a permeability reduction up to 3 orders of magnitude and strong baffling effects in the vadose zone. Carbonatic dilation bands show a permeability reduction of 1-2 orders of magnitude and no baffling structures. We distinguished two types of deformation bands in the carbonatic units, which differ in deformation mechanisms, distribution and composition. Full-cemented bands form as dilation bands with an intense syn-kinematic calcite cementation, whereas the younger loose-cemented bands are dilatant shear bands cemented by patchy calcite and clay minerals. All analyzed bands are characterized by a porosity and permeability reduction caused by grain fracturing and cementation. The changed petrophysical properties and especially the porosity evolution are closely related to diagenetic processes driven by varying pore fluids in different diagenetic environments. The deformation band evolution and sealing capacity is controlled by the initial host rock composition. PMID:26300577

  16. Characterization of mixing in a novel wavy-walled bioreactor for tissue engineering.

    Science.gov (United States)

    Bilgen, Bahar; Chang-Mateu, I Midey; Barabino, Gilda A

    2005-12-30

    The wavy-walled bioreactor (WWB) possesses a novel geometry comprised of walls with sinusoidal waves that mimic baffles in an effort to promote mixing. This geometry provides a unique hydrodynamic environment suitable for the cultivation of mammalian cells and tissues and the investigation of fluid mechanical effects on cell and tissue growth and development. In the present study, mixing in WWB was characterized and compared to that in a conventional spinner flask (SF). The key parameters included in this characterization were mixing time, residence time distribution (RTD), and dissolved oxygen concentration during engineered cartilage tissue cultivation. Factors that influenced mixing in WWB included wave amplitude, agitation rate, and the ratio of the impeller diameter to the tank diameter (D/T). Data obtained from RTD and acid base neutralization studies confirmed the presence of different mixing zones in WWB. A theoretical comparison of WWB to a baffled spinner flask (BSF) using computational fluid dynamics (CFD) modeling predicted that while enhanced mixing was achieved in wavy-walled and BSF bioreactors, the shear stresses applied on tissue constructs were 15% lower in WWB. Improved mixing was achieved in WWB compared to the SF at similar D/T ratios, verified by improved oxygen transport and increased dispersion. However, for lower D/T ratios mixing in WWB was not necessarily improved. This study demonstrated the importance of characterization of mixing by showing the impact of even minor changes in bioreactor geometry and operating conditions. Copyright 2005 Wiley Periodicals, Inc

  17. Liquid Self-Balancing Device Effects on Flexible Rotor Stability

    Directory of Open Access Journals (Sweden)

    Leonardo Urbiola-Soto

    2013-01-01

    Full Text Available Nearly a century ago, the liquid self-balancing device was first introduced by M. LeBlanc for passive balancing of turbine rotors. Although of common use in many types or rotating machines nowadays, little information is available on the unbalance response and stability characteristics of this device. Experimental fluid flow visualization evidences that radial and traverse circulatory waves arise due to the interaction of the fluid backward rotation and the baffle boards within the self-balancer annular cavity. The otherwise destabilizing force induced by trapped fluids in hollow rotors, becomes a stabilizing mechanism when the cavity is equipped with adequate baffle boards. Further experiments using Particle Image Velocimetry (PIV enable to assess the active fluid mass fraction to be one-third of the total fluid mass. An analytical model is introduced to study the effects of the active fluid mass fraction on a flexible rotor supported by flexible supports excited by bwo different destabilizing mechanisms; rotor internal friction damping and aerodynamic cross-coupling. It is found that the fluid radial and traverse forces contribute to the balancing action and to improve the rotor stability, respectively.

  18. Final Report: DOE/ID/14215

    Energy Technology Data Exchange (ETDEWEB)

    Kenneth Bryden; J. Richard Hess; Thomas Ulrich; Robert Zemetra

    2008-08-18

    efficiently engineer high-fidelity and high throughput separation systems for biomass components. INL and Iowa State University developed a computational modeling strategy for simulating multi-phase flow with an integrated solver using various computational fluid dynamics (CFD) codes. ISU set up a classic multi-phase test problem to be solved by the various CFD codes. The benchmark case was based on experimental data for bubble gas holdup and bed expansion for a gas/solid fluidized bed. Preliminary fluidization experiments identified some unexpected fluidization behavior, where rather than the bed uniformly fluidizing, a “blow out” would occur where a hole would open up in the bed through which the air would preferentially flow, resulting in erratic fluidization. To improve understanding of this phenomena and aid in building a design tool, improved computational tools were developed. The virtual engineering techniques developed were tested and utilized to design a separation baffle in a CNH combine. A computational engineering approach involving modeling, analysis, and simulation was used in the form of virtual engineering to design a baffle separator capable of accomplishing the high-fidelity residue separation established by the performance targets. Through the use of the virtual engineering model, baffle designs were simulated to (1) determine the effect of the baffle on the airflow of the combine cleaning system, and (2) predict the effectiveness of the baffle in separating the residue streams. A baffle design was selected based on the virtual engineering modeling, built into the INL selective harvest test combine. The result of the baffle changes improved the crop separation capability of the combine, enabling downstream improvement in composition and theoretical ethanol yield. In addition, the positive results from the application of the virtual engineering tools to the CNH combine design resulted in further application of these tools to other INL areas of research

  19. Assessing the applicability of the 1D flux theory to full-scale secondary settling tank design with a 2D hydrodynamic model.

    Science.gov (United States)

    Ekama, G A; Marais, P

    2004-02-01

    The applicability of the one-dimensional idealized flux theory (1DFT) for the design of secondary settling tanks (SSTs) is evaluated by comparing its predicted maximum surface overflow (SOR) and solids loading (SLR) rates with that calculated with the two-dimensional computational fluid dynamics model SettlerCAD using as a basis 35 full-scale SST stress tests conducted on different SSTs with diameters from 30 to 45m and 2.25-4.1m side water depth (SWD), with and without Stamford baffles. From the simulations, a relatively consistent pattern appeared, i.e. that the 1DFT can be used for design but its predicted maximum SLR needs to be reduced by an appropriate flux rating, the magnitude of which depends mainly on SST depth and hydraulic loading rate (HLR). Simulations of the Watts et al. (Water Res. 30(9)(1996)2112) SST, with doubled SWDs and the Darvill new (4.1m) and old (2.5m) SSTs with interchanged depths, were run to confirm the sensitivity of the flux rating to depth and HLR. Simulations with and without a Stamford baffle were also performed. While the design of the internal features of the SST, such as baffling, has a marked influence on the effluent SS concentration while the SST is underloaded, these features appeared to have only a small influence on the flux rating, i.e. capacity, of the SST. Until more information is obtained, it would appear from the simulations that the flux rating of 0.80 of the 1DFT maximum SLR recommended by Ekama and Marais (Water Pollut. Control 85(1)(1986)101) remains a reasonable value to apply in the design of full-scale SSTs-for deep SSTs (4m SWD) the flux rating could be increased to 0.85 and for shallow SSTs (2.5m SWD) decreased to 0.75. It is recommended that (i) while the apparent interrelationship between SST flux rating and depth suggests some optimization of the volume of the SST, this be avoided and (ii) the depth of the SST be designed independently of the surface area as is usually the practice and once selected, the

  20. Biventricular repair in double outlet right ventricle: surgical results based on the STS-EACTS International Nomenclature classification.

    Science.gov (United States)

    Artrip, John H; Sauer, Henning; Campbell, David N; Mitchell, Max B; Haun, Christoph; Almodovar, Melvin C; Hraska, Viktor; Lacour-Gayet, Francois

    2006-04-01

    The STS-EACTS International Nomenclature for Congenital Heart Surgery (CHS) defines four anatomic subtypes of double outlet right ventricle (DORV) based on the relationship of the ventricular septal defect (VSD) with the great vessels and the presence of right ventricular outflow tract obstruction (RVOTO). We reviewed our experience with DORV patients and two ventricles that underwent repair, applying this nomenclature. Between January 2000 and January 2005, 50 patients with DORV and two viable ventricles underwent surgical intervention: 44 patients had biventricular repair, 3 had 1.5 ventricular repair, 2 underwent a Fontan, and 1 died prior to corrective surgery. Median age at repair was 9.1 months (range: 4D-4Y). Eighteen patients (36%) were DORV-Fallot (including 5 with AVSD and heterotaxy), 9 (18%) were DORV-TGA (Taussig-Bing), 12 (24%) were DORV-VSD, and 11 (22%) were DORV non-committed VSD. Corrective surgery included 35 repairs with a VSD-aorta baffle+/-RVOTO procedure and 12 arterial switches with a VSD-PA baffle (9 Taussig-Bing and 3 DORV-ncVSD). Associated procedures included 13 VSD enlargements, 8 subaortic resections, 9 arch repairs, 5 AVSD repairs, and 7 others. There were three deaths in the 50 patients studied (overall mortality of 6%). Excluding one patient that died prior to corrective surgery and the two patients palliated with a Fontan procedure, the actual surgical mortality for a corrective repair was 4.3% (2/47 patients). Two surgical deaths occurred following, respectively, one repair of a Taussig-Bing with an interrupted arch and a Swiss cheese VSD and one repair of ncVSD-type with pulmonary atresia that had undergone a previous cavo-pulmonary anastamosis. No late deaths occurred. Two late reoperations included a heart transplant in a DORV-Fallot patient with Swiss cheese VSD and subaortic resection in a DORV-ncVSD patient. Angioplasties were needed for PA stenosis (n=2) and aortic arch obstruction (n=2). Four patients had LV to aorta

  1. Power stabilized CO2 gas transport laser

    International Nuclear Information System (INIS)

    Foster, J.D.; Kirk, R.F.; Moreno, F.E.; Ahmed, S.A.

    1975-01-01

    The output power of a high power (1 kW or more) CO 2 gas transport laser is stabilized by flowing the gas mixture over copper plated baffles in the gas channel during operation of the laser. Several other metals may be used instead of copper, for example, nickel, manganese, palladium, platinum, silver and gold. The presence of copper in the laser gas circuit stabilizes output power by what is believed to be a compensation of the chemical changes in the gas due to the cracking action of the electrical discharge which has the effect of diminishing the capactiy of the carbon dioxide gas mixture to maintain the rated power output of the laser. (U.S.)

  2. Children value informativity over logic in word learning.

    Science.gov (United States)

    Ramscar, Michael; Dye, Melody; Klein, Joseph

    2013-06-01

    The question of how children learn the meanings of words has long puzzled philosophers and psychologists. As Quine famously pointed out, simply hearing a word in context reveals next to nothing about its meaning. How then do children learn to understand and use words correctly? Here, we show how learning theory can offer an elegant solution to this seemingly intractable puzzle in language acquisition. From it, we derived formal predictions about word learning in situations of Quinean ambiguity, and subsequently tested our predictions on toddlers, undergraduates, and developmental psychologists. The toddlers' performance was consistent both with our predictions and with the workings of implicit mechanisms that can facilitate the learning of meaningful lexical systems. Adults adopted a markedly different and likely suboptimal strategy. These results suggest one explanation for why early word learning can appear baffling: Adult intuitions may be a poor source of insight into how children learn.

  3. Large area SiC coating technology of RBSC for semiconductor processing component

    International Nuclear Information System (INIS)

    Park, Ji Yeon; Kim, Weon Ju

    2001-06-01

    As the semiconductor process is developed for the larger area wafer and the larger-scale integration, the processing fixtures are required to have excellent mechanical and high temperature properties. This highlights the importance of silicon carbide-based materials as a substitute for quartz-based susceptors. In this study, SiC coating technology on reaction sintered (RS) SiC with thickness variation of +/- 10% within a diameter of 8 inch by low pressure chemical vapor deposition has been developed for making a plate type SiC fixture such as heater, baffle, etc., with a diameter of 12 inch. Additionally, a state of art on fabrication technology and products of the current commercial SiC fixtures has been described

  4. Vocabulary Acquisition for Future Nursing Staff: authenticity in the classroom

    Directory of Open Access Journals (Sweden)

    Kirsten Hempkin

    2015-11-01

    Full Text Available Research suggests that many ESL teachers either modify or supplement the set textbooks they use in class, or develop their own materials for classroom use. Indeed, in recent years, the internet in particular has opened up a rich and at times perhaps baffling array of resources for those ESL practitioners who wish to incorporate authentic materials into their teaching. While the benefits of authentic materials are well-documented, their use is, however, not entirely unproblematic, and as research into the field of material (authentic or otherwise development grows, this raises a number of issues as to the form these materials should take and how they can best be employed. This article presents a set of vocabulary building activities for future nursing staff; these activities are in use at the Faculty of Health Sciences in Maribor. The article explains the rationale behind them in light of the theoretical framework of language acquisition that underpins them.

  5. Radiotracer study in a bubble column reactor (visbreaker)

    International Nuclear Information System (INIS)

    Pant, H.J.; Sharma, V.K.; Gursharan Singh; Rohit Kulkarni; Pandit, A.B.; Kumar, M.M.; Berne, Ph.

    2004-01-01

    Radiotracer technique was used to measure residence time distribution (RTD) of fuel oil in a pilot-plant visbreaker with an objective to investigate hydrodynamic behaviour at different operating conditions. Bromine-82 as dibromobiphenyle was used as a tracer to measure RTD of the fuel oil. Mean residence times were determined from the measured RTD data. Tanks-in-series with backmixing model was used to simulate the measured RTD data. The results of simulation indicated that the visbreaker did not behave as a plug flow reactor as desired for visbreaking process. The presence of internals i.e. baffles inside the visbreaker decreases the mean residence time and backmixing. Thus, the designed internals have shown promising effect in terms of reduced backmixing in the visbreaker. (author)

  6. Computerized heat balance models to predict performance of operating nuclear power plants

    International Nuclear Information System (INIS)

    Breeding, C.L.; Carter, J.C.; Schaefer, R.C.

    1983-01-01

    The use of computerized heat balance models has greatly enhanced the decision making ability of TVA's Division of Nuclear Power. These models are utilized to predict the effects of various operating modes and to analyze changes in plant performance resulting from turbine cycle equipment modifications with greater speed and accuracy than was possible before. Computer models have been successfully used to optimize plant output by predicting the effects of abnormal condenser circulating water conditions. They were utilized to predict the degradation in performance resulting from installation of a baffle plate assembly to replace damaged low-pressure blading, thereby providing timely information allowing an optimal economic judgement as to when to replace the blading. Future use will be for routine performance test analysis. This paper presents the benefits of utility use of computerized heat balance models

  7. Single Crystal Casting with Fluidized Carbon Bed Cooling: A Process Innovation for Quality Improvement and Cost Reduction

    Science.gov (United States)

    Hofmeister, M.; Franke, M. M.; Koerner, C.; Singer, R. F.

    2017-12-01

    Superalloy gas turbine blades are being produced by investment casting and directional solidification. A new process, Fluidized Carbon Bed Cooling (FCBC), has been developed and is now being optimized in a prototype casting unit with 10 kg pouring weight. In early test runs with still rather simple mold cluster geometries, a reduction of the primary dendrite arm spacing of around 40 pct compared to the standard radiation cooling process (HRS) could be demonstrated. The improvement is mainly attributed to higher temperature gradients driving solidification, made possible by a functioning Dynamic Baffle. Compared to earlier development efforts in the literature, contamination of the melt and damage to the equipment are avoided using carbon-based fluidized bed materials and the so-called "counter pressure concept."

  8. Optimization of magnetic amplification by flow constraints in turbulent liquid sodium

    International Nuclear Information System (INIS)

    Nornberg, M. D.; Taylor, N. Z.; Forest, C. B.; Rahbarnia, K.; Kaplan, E.

    2014-01-01

    Direct measurements of the vector turbulent emf in a driven two-vortex flow of liquid sodium were performed in the Madison Dynamo Experiment [K. Rahbarnia et al., Astrophys. J. 759, 80 (2012)]. The measured turbulent emf is anti-parallel with the mean current and is almost entirely described by an enhanced resistivity, which increases the threshold for a kinematic dynamo. We have demonstrated that this enhanced resistivity can be mitigated by eliminating the largest-scale eddies through the introduction of baffles. By tailoring the flow to reduce large-scale components and control the helical pitch, we have reduced the power required to drive the impellers, doubled the magnetic flux generated by differential rotation, and increased the decay time of externally applied magnetic fields. Despite these improvements, the flows remain sub-critical to the dynamo instability due to the reemergence of turbulent fluctuations at high flow speeds

  9. Multispectral and stereo imaging on Mars

    Science.gov (United States)

    Levinthal, E. C.; Huck, F. O.

    1976-01-01

    Relevant aspects of the design and function of the two-window Viking Landing Camera system are described, with particular reference to some results of its operation on Mars during the Viking mission. A major feature of the system is that the optical tunnel between the lens and the photosensor array contains a multiaperture baffle designed to reduce veiling glare and to attenuate radio frequency interference from the lander antennas. The principle of operation of the contour mode is described. The accuracy is limited by the stereo base, resolution of camera picture elements, and geometric calibration. To help determine the desirability as well as the safety of possible sample sites, use is made of both radiometric and photogrammetric information for each picture element to combine high-resolution pictures with low-resolution color pictures of the same area. Explanatory photographs supplement the text.

  10. Continuous Production of IF-WS2 Nanoparticles by a Rotary Process

    Directory of Open Access Journals (Sweden)

    Fang Xu

    2014-06-01

    Full Text Available This manuscript demonstrates the design, modification and initial investigation of a rotary furnace for the manufacturing of inorganic fullerene WS2 nanoparticles. Different preparation methods starting with various precursors have been investigated, of which the gas-solid reaction starting with WO3 nanoparticles was the most efficient technique. Furthermore, the influence of temperature, reaction time, and reaction gases etc. on the synthesis of inorganic fullerene WS2 nanomaterials was investigated, and these parameters were optimised based on combined characterisations using XRD, SEM and TEM. In addition, the furnace was further modified to include a baffled tube, a continuous gas-blow feeding system, and a collection system, in order to improve the batch yield and realise continuous production. This technique has improved the production from less than 1 g/batch in a traditional tube furnace to a few tens of g/batch, and could be easily scaled up to industry level production.

  11. Acoustical analysis of gear housing vibration

    Science.gov (United States)

    Seybert, A. F.; Wu, T. W.; Wu, X. F.; Oswald, Fred B.

    1991-01-01

    The modal and acoustical analysis of the NASA gear-noise rig is described. Experimental modal analysis techniques were used to determine the modes of vibration of the transmission housing. The resulting modal data were then used in a boundary element method (BEM) analysis to calculate the sound pressure and sound intensity on the surface of the housing as well as the radiation efficiency of each mode. The radiation efficiencies of the transmission housing modes are compared with theoretical results for finite, baffled plates. A method that uses the measured mode shapes and the BEM to predict the effect of simple structural changes on the sound radiation efficiency of the modes of vibration is also described.

  12. Instrumentation for accelerators

    International Nuclear Information System (INIS)

    Sen, T.J.; De, T.K.; Ranganathan, M.K.; Basak, G.C.

    1989-01-01

    Along with the various system development for the accelerator, it was necessary to develop the instrumentation facility for the cyclotron. It started with the development of various vacuum instruments like ionization gauge control unit for measurement of pressure from 10 -4 torr to 10 -9 torr, discharge gauge control unit from 10 -4 torr to 10 -7 torr, thermocouple gauge control unit from 1 torr to 10 -3 torr. Process control instrumentation includes temperature measurement for freon cooled baffle and als o for low conductivity water. Control console required various digital panel meters for measurement of various parameters of the cyclotron. Various radiation monitoring instruments are also taken care of by the instrumentation facility. This paper describes in brief these various instruments. (author). 3 f igs

  13. Study of Lithium Vapor Flow In a Detached Divertor using DSMC code

    Science.gov (United States)

    Emdee, Eric; Schwartz, Jacob; Goldston, Robert; Jaworski, Michael

    2017-10-01

    A detached divertor is predicted to be necessary to handle the heat fluxes of a demonstration fusion power plant. The lithium vapor box divertor has poloidal baffles to form distinct chambers and contains dense lithium vapor to cause detachment. These chambers would be differentially pumped via condensation, resulting in flow at Knudsen numbers 0.01-0.5 and densities 1019-1023m-3. This divertor geometry is predicted to handle the estimated heat flux while also localizing the vapor in the divertor. We provide a simulation of the divertor's lithium vapor flow using the SPARTA Direct Simulation Monte Carlo (DSMC) code. Lithium mass flow, vapor pressures, and temperatures within each chamber are given. Preliminary simulations of a vapor box divertor similarity experiment are within 30% of an ideal-gas choked nozzle flow calculation. This work supported by DOE Contract No. DE-AC02-09CH11466.

  14. Operational characteristics of VEC vacuum system

    International Nuclear Information System (INIS)

    Viswanadham, C.; Bhavsar, S.T.; Bose, D.K.; Chintalapudi, S.N.; Das, S.K.; Tiwary, S.D.

    1979-01-01

    The main vacuum system of the Variable Energy Cyclotron which has been built indigenously has fulfilled the requirements for the smooth operation of the machine. By running two 88.9 cm diffusion pumps with freon cooled baffles and backed by 600 l/m rotary pumps, a pressure of 5 x 10 -6 torr in absence of the beam and 1 x 10 -5 torr in presence of the beam is readily achieved in the 23 m 3 volume. Various means have been adopted to maintain the system in order and contamination-free, by maintaining a pressure level of 1 x 10 -4 torr throughout the working week by a 30 cm diffusion pump, which can run even on emergency power. Cryopanels have also been installed and tried out. Details of pump-down characteristics and system performance are discussed. (auth.)

  15. Hydrogeochemistry in a relatively unmodified subtropical catchment: Insights regarding the health and aesthetic risks of manganese

    Directory of Open Access Journals (Sweden)

    Adam K. Rose

    2017-10-01

    New hydrological insights for region: Results show that the hydrogeochemistry of Baffle Creek was predominantly driven by rain events, with differing responses to varying magnitudes of rain and discharge. Following a flushing event, dissolved aluminium and nitrate increased in the surface and drinking water, whereas manganese and ammonia were undetectable in the drinking water and occurred only in small concentrations in the surface waters. In contrast, when rainfall events occurred without an associated flush, manganese, iron and ammonia concentrations increased in the drinking water. The hydrochemistry of manganese and iron in the supply chain infrastructure was strongly positively correlated with ammonia, and aluminium correlated with nitrate concentrations. Currently the drinking water supply does not pose a threat to chronic manganese exposure for humans, however elevated concentrations are experienced periodically; and may become more problematic under climate change scenarios.

  16. Prolegomena to any future metaphysics that will be able to come forward as science the Paul Carus translation

    CERN Document Server

    Kant, Immanuel

    1977-01-01

    Kant’s Prolegomena -- its full title, in the eighteenth-century manner, is Prolegomena to Any Future Metaphysics Which Will Be Able to Come Forth as Science -- is a classic in metaphysics and the theory of knowledge. It deals with the perennially baffling questions: How do we know? How much can we know? Its answers to these questions are interesting especially now. We live in one of the recurring periods of intellectual and cultural history that are skeptical and impatient of systems of speculative metaphysics, and a distrust of speculation is the leading motif of the Prolegomena. Though Kant's arguments against speculative metaphysics differ from those of our contemporaries, in some of his results he anticipates their negative conclusions. The Prolegomena, however, is not interesting merely as an historical anticipation of recent views; indeed, as such it has been as it were condemned in advance by Kant (Prolegomena, Introduction). Rather, its chief interest to the student of philosophy is probably the way...

  17. Black silicon integrated aperture

    Science.gov (United States)

    Liu, Tianbo; Dickensheets, David L.

    2017-10-01

    This paper describes the incorporation of nanotextured black silicon as an optical absorbing material into silicon-based micro-optoelectromechanical systems devices to reduce stray light and increase optical contrast during imaging. Black silicon is created through a maskless dry etch process and characterized for two different etch conditions, a cold etch performed at 0°C and a cryogenic etch performed at -110°C. We measure specular reflection at visible wavelengths to be black velvet paint used to coat optical baffles and compare favorably with other methods to produce black surfaces from nanotextured silicon or using carbon nanotubes. We illustrate the use of this material by integrating a black silicon aperture around the perimeter of a deformable focus-control mirror. Imaging results show a significant improvement in contrast and image fidelity due to the effective reduction in stray light achieved with the self-aligned black aperture.

  18. Why Do Markets Crash? Bitcoin Data Offers Unprecedented Insights.

    Directory of Open Access Journals (Sweden)

    Jonathan Donier

    Full Text Available Crashes have fascinated and baffled many canny observers of financial markets. In the strict orthodoxy of the efficient market theory, crashes must be due to sudden changes of the fundamental valuation of assets. However, detailed empirical studies suggest that large price jumps cannot be explained by news and are the result of endogenous feedback loops. Although plausible, a clear-cut empirical evidence for such a scenario is still lacking. Here we show how crashes are conditioned by the market liquidity, for which we propose a new measure inspired by recent theories of market impact and based on readily available, public information. Our results open the possibility of a dynamical evaluation of liquidity risk and early warning signs of market instabilities, and could lead to a quantitative description of the mechanisms leading to market crashes.

  19. Optimized and Automated design of Plasma Diagnostics for Additive Manufacture

    Science.gov (United States)

    Stuber, James; Quinley, Morgan; Melnik, Paul; Sieck, Paul; Smith, Trevor; Chun, Katherine; Woodruff, Simon

    2016-10-01

    Despite having mature designs, diagnostics are usually custom designed for each experiment. Most of the design can be now be automated to reduce costs (engineering labor, and capital cost). We present results from scripted physics modeling and parametric engineering design for common optical and mechanical components found in many plasma diagnostics and outline the process for automated design optimization that employs scripts to communicate data from online forms through proprietary and open-source CAD and FE codes to provide a design that can be sent directly to a printer. As a demonstration of design automation, an optical beam dump, baffle and optical components are designed via an automated process and printed. Supported by DOE SBIR Grant DE-SC0011858.

  20. ALPHA/PHOENIX-P/ANC system validation for Angra-1 neutronic calculations

    International Nuclear Information System (INIS)

    Ponzoni Filho, Pedro; Sato, Sadakatu; Santos, Teresinha Ipojuca Cardoso; Fernandes, Vanderlei Borba; Fetterman, R.J.

    1995-01-01

    The ALPHA/PHOENIX-P/ANC (APA) code package is an advanced neutronic calculation system for pressurized water reactor (PWR). PHOENIX-P generates the required cross sections for the fuel, burnable absorbers, control rods and baffle/reflector region. The ALPHA code is used to automate the generation of these cross-sections as well as process the PHOENIX-P results to generate the ANC model input. ANC is a three dimensional advanced nodal code used for the modeling of the, depletion of the fuel in the core, and for the calculation of power distributions, rod worths and other reactivity parameters. This paper provides brief overview of the APA methodology for reload core design of Angra Unit 1 Cycles 1 and 2. Results included are predicted power distributions, control rod worths and other reactivity parameters compared to plant measurements. These results demonstrate that the APA system can be used for the reload core design. (author). 7 refs, 9 figs

  1. Analysis of heat transfer in a heated tube with a different typed disc insertion

    Directory of Open Access Journals (Sweden)

    Turan Betül

    2012-01-01

    Full Text Available Heat transfer and fluid flow can be controlled in a tube by inserting different typed passive elements. The main objective of this study is to control heat transfer and fluid flow using cutting edged disc in pipe. Governing equations of laminar, two-dimensional flow is solved via finite volume technique. The disc is adiabatic and its thickness is 5mm. It is located into axial axis of the tube. Three cases were applied based on the type of the disc as inclination angle of the top side is 45º and 0º. Calculations were performed for different Reynolds number in the range of 335 < Re < 845. Three cases were tested based on types of discs. It is observed that each position exhibits different heat transfer ratio according to studied Reynolds number. The highest heat transfer is formed when inlet flow impinges to flat side of the cutting edged baffle.

  2. Numerical simulation of flow induced by a pitched blade turbine. Comparison of the sliding mesh technique and an averaged source term method

    Energy Technology Data Exchange (ETDEWEB)

    Majander, E.O.J.; Manninen, M.T. [VTT Energy, Espoo (Finland)

    1996-12-31

    The flow induced by a pitched blade turbine was simulated using the sliding mesh technique. The detailed geometry of the turbine was modelled in a computational mesh rotating with the turbine and the geometry of the reactor including baffles was modelled in a stationary co-ordinate system. Effects of grid density were investigated. Turbulence was modelled by using the standard k-{epsilon} model. Results were compared to experimental observations. Velocity components were found to be in good agreement with the measured values throughout the tank. Averaged source terms were calculated from the sliding mesh simulations in order to investigate the reliability of the source term approach. The flow field in the tank was then simulated in a simple grid using these source terms. Agreement with the results of the sliding mesh simulations was good. Commercial CFD-code FLUENT was used in all simulations. (author)

  3. The physics of neutrinos

    CERN Document Server

    Barger, Vernon D; Whisnant, Kerry

    2012-01-01

    The physics of neutrinos- uncharged elementary particles that are key to helping us better understand the nature of our universe - is one of the most exciting frontiers of modern science. This book provides a comprehensive overview of neutrino physics today and explores promising new avenues of inquiry that could lead to future breakthroughs. The Physics of Neutrinos begins with a concise history of the field and a tutorial on the fundamental properties of neutrinos, and goes on to discuss how the three neutrino types interchange identities as they propagate from their sources to detectors. The book shows how studies of neutrinos produced by such phenomena as cosmic rays in the atmosphere and nuclear reactions in the solar interior provide striking evidence that neutrinos have mass, and it traces our astounding progress in deciphering the baffling experimental findings involving neutrinos. The discovery of neutrino mass offers the first indication of a new kind of physics that goes beyond the Standard Model ...

  4. A six-circle diffractometer system for synchrotron X-ray studies of surfaces and thin film growth by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Hong, Hawoong; Chiang, T.-C.

    2007-01-01

    A new ultrahigh vacuum (UHV) surface diffractometer system equipped with molecular beam epitaxy (MBE) capabilities has been developed. It has a versatile 6-circle configuration for defining the diffraction geometry, and a three-axis translation stage for controlling the sample position. Rugged mechanical components are employed in the design to allow accurate diffraction measurements. Sample cooling is facilitated by passing liquid nitrogen into a reservoir in the base of a sample mount. The sample can be heated to very high temperatures by either direct current heating or electron beam bombardment. During film growth and processing, the sample temperature, monitored by thermocouples, can be continuously and rapidly varied between ∼110 K to above room temperature. A charge coupled device (CCD) camera, attached to the μ circle, allows rapid reciprocal space mapping for real time studies of sample growth and evolution during deposition and annealing. A beam stop and a baffle are implemented to minimize stray scattered radiation

  5. Stabilization of arsenic and chromium polluted soils using water treatment residues

    DEFF Research Database (Denmark)

    Nielsen, Sanne Skov

    or other sorbents. Iron water treatment residues mainly consist of ferrihydrite, an oxidized iron oxy-hydroxide with a high reactivity and a large specific surface area with a high capacity for adsorption. Iron water treatment residues (Fe-WTR) are a by-product from treatment of groundwater to drinking...... in the leachate from an amended, slightly polluted soil (255 mg/kg As and 27 mg/kg Cr) did not at any time exceed 50 μg/L, which means that the soil can be reused for construction e.g. roads and baffle walls as described by the Danish Reuse Act. Ageing of ferrihydrite, the main constituent of Fe...

  6. Effect of solenoidal magnetic field on drifting laser plasma

    Science.gov (United States)

    Takahashi, Kazumasa; Okamura, Masahiro; Sekine, Megumi; Cushing, Eric; Jandovitz, Peter

    2013-04-01

    An ion source for accelerators requires to provide a stable waveform with a certain pulse length appropriate to the application. The pulse length of laser ion source is easy to control because it is expected to be proportional to plasma drifting distance. However, current density decay is proportional to the cube of the drifting distance, so large current loss will occur under unconfined drift. We investigated the stability and current decay of a Nd:YAG laser generated copper plasma confined by a solenoidal field using a Faraday cup to measure the current waveform. It was found that the plasma was unstable at certain magnetic field strengths, so a baffle was introduced to limit the plasma diameter at injection and improve the stability. Magnetic field, solenoid length, and plasma diameter were varied in order to find the conditions that minimize current decay and maximize stability.

  7. Optimization and reconstruction technology of SCR flue gas denitrification ultra low emission in coal fired power plant

    Science.gov (United States)

    Li, Xinhao

    2017-09-01

    In recent decades, nitrogen oxides (NOx) emissions from thermal power plant increased year by year in China. A large number of nitrogen oxides (NOx) emissions caused by the growing environmental problems have been widely attached importance to people. SCR denitrification technology has the advantages of cleanliness and high efficiency. At present, it has been the major technology to control NOx emission because of its high denitrification efficiency, reliable operation, no by-products and simple structure of the device. The denitrification efficiency can be stabilized at 70%. In this paper, three different denitrification methods are compared. The factors influencing the denitrification efficiency, the system arrangement and the key factors of the denitrification system are discussed in detail. And the numerical simulation of how to use this calculation software in the SCR reactor flue, baffle, reactor, spray ammonia grille and spray ammonia, mixer, etc. are reviewed, as well as the effect of system operation control on the deoxidation performance.

  8. Hot water tank for use with a combination of solar energy and heat-pump desuperheating

    Science.gov (United States)

    Andrews, John W.

    1983-06-28

    A water heater or system which includes a hot water tank having disposed therein a movable baffle to function as a barrier between the incoming volume of cold water entering the tank and the volume of heated water entering the tank which is heated by the circulation of the cold water through a solar collector and/or a desuperheater of a heat pump so as to optimize the manner in which heat is imparted to the water in accordance to the demand on the water heater or system. A supplemental heater is also provided and it is connected so as to supplement the heating of the water in the event that the solar collector and/or desuperheater cannot impart all of the desired heat input into the water.

  9. Stemming and containment phenomenology for the Hybla Fair event

    International Nuclear Information System (INIS)

    Swift, R.P.; Burton, D.E.

    1980-01-01

    The Hybla Fair underground nuclear event was conducted by the Defense Nuclear Agency (DNA) to assess the feasibility of using low yield devices to reduce the expense of nuclear weapons effects testing. The economy of low yield tests was facilitated by placing of the test bed chamber closer to the source, thereby allowing the use of a shorter horizontal line-of-sight (HLOS) tunnel than used for higher yield testing. One main design concern for the Hybla Fair event centered around the desire for the radiation environment in the test chamber to be equivalent to that of higher yield tests. This concern imposed a severe constraint on the stemming column design. Studies of the required Hybla Fair stemming configuration, of the phenomenology of ground shock-induced stemming plug formation for low-yield events, of the effects of baffles on the stemming process, and of the integrity of the stemming closure region for the containment of the cavity gases are reported

  10. Radioisotope space power generator annual report for the period October 1, 1976-September 30, 1978

    International Nuclear Information System (INIS)

    Elsner, N.B.; Chin, J.; Staley, H.G.; Bass, J.C.; Steeger, E.J.; Gantzel, P.K.; Neill, J.M.

    1980-01-01

    Techniques for fabricating P-type (Cu,Ag) 2 Se with mesh-type bonds have been developed and are being evaluated for long-term use. In addition, methods for reducing vapor suppression by the use of coatings and/or baffling continue to show gains. The N-type alloy Gd 2 Se 3 has been shown to be thermally unstable. It undergoes a sluggish cubic-to-orthorhombic phase change below 1000 0 C, with an accompanying degradation in mechanical and thermoelectric properties. Fabrication studies conducted with the (Bi,Sb) 2 (Se,Te) 3 alloys showed these materials to be sensitive to oxygen contamination if reproducible properties are to be obtained. Preparation of powdered material by explosive techniques was investigated. This technique appears to be useful in preparing homogeneous -325 mesh material, but it does not yield a useful amount of submicron-size powder

  11. Modification of tungsten layers by arcing

    International Nuclear Information System (INIS)

    Laux, M.; Schneider, W.; Juettner, B.; Lindig, S.; Mayer, M.; Balden, M.; Beilis, I.; Djakov, B.

    2005-01-01

    Numerous traces of arcs have been found on W-covered graphite tiles of ASDEX Upgrade after exposure. The distributions of number density, lengths and orientation are calculated and compared to pure graphite tiles at comparable locations. It was established that arcs perforate a 1 μm tungsten layer down to the carbon substrate. The amount of removal should rise with arc current, but a surface fraction of about 8% is eroded at 10 A already. At tiles of the divertor baffle the layer is continuously removed along the entire track pointing to higher currents. The carbon of the stripped parts is subject to subsequent erosion processes. The distribution of materials in and around arc tracks was investigated by sputter depth profiling (SIMS and AES) and the characteristic geometry was studied using an electron microscope. Observations are interpreted using results from laboratory vacuum arcs on the same material

  12. Status on the Verification of Combustion Stability for the J-2X Engine Thrust Chamber Assembly

    Science.gov (United States)

    Casiano, Matthew; Hinerman, Tim; Kenny, R. Jeremy; Hulka, Jim; Barnett, Greg; Dodd, Fred; Martin, Tom

    2013-01-01

    Development is underway of the J -2X engine, a liquid oxygen/liquid hydrogen rocket engine for use on the Space Launch System. The Engine E10001 began hot fire testing in June 2011 and testing will continue with subsequent engines. The J -2X engine main combustion chamber contains both acoustic cavities and baffles. These stability aids are intended to dampen the acoustics in the main combustion chamber. Verification of the engine thrust chamber stability is determined primarily by examining experimental data using a dynamic stability rating technique; however, additional requirements were included to guard against any spontaneous instability or rough combustion. Startup and shutdown chug oscillations are also characterized for this engine. This paper details the stability requirements and verification including low and high frequency dynamics, a discussion on sensor selection and sensor port dynamics, and the process developed to assess combustion stability. A status on the stability results is also provided and discussed.

  13. Why Do Markets Crash? Bitcoin Data Offers Unprecedented Insights.

    Science.gov (United States)

    Donier, Jonathan; Bouchaud, Jean-Philippe

    2015-01-01

    Crashes have fascinated and baffled many canny observers of financial markets. In the strict orthodoxy of the efficient market theory, crashes must be due to sudden changes of the fundamental valuation of assets. However, detailed empirical studies suggest that large price jumps cannot be explained by news and are the result of endogenous feedback loops. Although plausible, a clear-cut empirical evidence for such a scenario is still lacking. Here we show how crashes are conditioned by the market liquidity, for which we propose a new measure inspired by recent theories of market impact and based on readily available, public information. Our results open the possibility of a dynamical evaluation of liquidity risk and early warning signs of market instabilities, and could lead to a quantitative description of the mechanisms leading to market crashes.

  14. Engineering task plan for the vapor monitor installation into 241-C-103 tank

    International Nuclear Information System (INIS)

    Hertelendy, N.A.

    1994-12-01

    A vapor flow monitor is to be installed into the 241-C-103 tank's exhaust, just downstream of the HEPA filter. The flow monitor system includes the flow sensor, the baffle assembly, the signal conditioning and control electronics, and a chart recorder. The electronics package and the chart recorder are installed into a small, heated instrument cabinet that is mounted on the same steel pallet on which the flowmeter and the diffuser assembly is mounted. The flowmeter is connected to the HEPA filter with an unheated, un-insulated flex hose. An automatic drain, upstream of the flowmeter, is designed to automatically drain the condensate into an evaporating pan. The flowmeter is heated with a temperature controlled heater to avoid condensation

  15. Turbulent precipitation of uranium oxalate in a vortex reactor - experimental study and modelling; Precipitation turbulente d'oxalate d'uranium en reacteur vortex - etude experimentale et modelisation

    Energy Technology Data Exchange (ETDEWEB)

    Sommer de Gelicourt, Y

    2004-03-15

    Industrial oxalic precipitation processed in an un-baffled magnetically stirred tank, the Vortex Reactor, has been studied with uranium simulating plutonium. Modelling precipitation requires a mixing model for the continuous liquid phase and the solution of population balance for the dispersed solid phase. Being chemical reaction influenced by the degree of mixing at molecular scale, that commercial CFD code does not resolve, a sub-grid scale model has been introduced: the finite mode probability density functions, and coupled with a model for the liquid energy spectrum. Evolution of the dispersed phase has been resolved by the quadrature method of moments, first used here with experimental nucleation and growth kinetics, and an aggregation kernel based on local shear rate. The promising abilities of this local approach, without any fitting constant, are strengthened by the similarity between experimental results and simulations. (author)

  16. Corot telescope (COROTEL)

    Science.gov (United States)

    Viard, Thierry; Mathieu, Jean-Claude; Fer, Yann; Bouzou, Nathalie; Spalinger, Etienne; Chataigner, Bruno; Bodin, Pierre; Magnan, Alain; Baglin, Annie

    2017-11-01

    COROTEL is the telescope of the COROT Satellite which aims at measuring stellar flux variations very accurately. To perform this mission, COROTEL has to be very well protected against straylight (from Sun and Earth) and must be very stable with time. Thanks to its high experience in this field, Alcatel Alenia Space has proposed, manufactured and tested an original telescope concept associated with a high baffling performance. Since its delivery to LAM (Laboratoire d'Astrophysique de Marseille, CNRS) the telescope has passed successfully the qualification tests at instrument level performed by CNES. Now, the instrument is mounted on a Proteus platform and should be launched end of 2006. The satellite should bring to scientific community for the first time precious data coming from stars and their possible companions.

  17. Development of a ten inch manipulators-based, flexible, broadband two-crystal spectrometer

    Science.gov (United States)

    Steel, A. B.; Dunn, J.; Emig, J.; Beiersdorfer, P.; Brown, G. V.; Shepherd, R.; Marley, E. V.; Hoarty, D. J.

    2014-11-01

    We have developed and implemented a broadband X-ray spectrometer with a variable energy range for use at the Atomic Weapons Establishment's Orion Laser. The spectrometer covers an energy bandwidth of ˜1-2 keV using two independently mounted, movable Bragg diffraction crystals. Using combinations of cesium hydrogen pthlate, ammonium dihydrogen phosphate, and pentaerythritol crystals, spectra covering the 1.4-2.5, 1.85-3.15, or 3.55-5.1 keV energy bands have been measured. Image plate is used for detection owing to its high dynamic range. Background signals caused by high energy X-rays and particles commonly produced in high energy laser experiments are reduced by a series of tantalum baffles and filters installed between the source and crystal and also between the crystals and detector.

  18. [Optimization of Energy Saving Measures with ABR-MBR Integrated Process].

    Science.gov (United States)

    Wu, Peng; Lu, Shuang-jun; Xu, Yue-zhong; Liu, Jie; Shen, Yao-liang

    2015-08-01

    High energy consumption and membrane fouling are important factors that limit the wide use of membrane bioreactor (MBR). In order to reduce energy consumption and delay the process of membrane fouling, the process of anaerobic baffled reactor (ABR)-MBR was used to treat domestic sewage. The structure of the process and conditions of nitrogen and phosphorus removal were optimized in this study. The results showed that energy consumption was reduced by 43% through optimizing the structure of ABR-MBR process. Meanwhile, the process achieved a high level of COD, NH: -N, TN and TP removal, with the average removal efficiencies of 91%, 85%, 76% and 86%, respectively. In addition, the added particulate media could effectively delay membrane fouling, while the formation process of membrane fouling was changed. The extracted amount of carbohydrates increased while the amount of proteins decreased. Finally, the potential was enhanced for the practical application of MBR.

  19. Application and verification of cold air velocity technique for solving tube ash erosion problem in PC boilers

    International Nuclear Information System (INIS)

    Yoo, Kisoo; Jeong, Kwon Seok

    2012-01-01

    Fly ash erosion is a leading cause of boiler tube failure in PC boilers. Therefore, shields or baffle plates are installed in specific areas to mitigate fly ash erosion and prevent boiler tube failure. However, the tube failure problems caused by fly ash erosion cannot be eliminated with this solution alone, because each PC boiler has a different flue gas flow pattern and erosion can become severe in unexpected zones. This problem is caused by an asymmetric internal flow velocity and local growth of the flue gas velocity. For these reasons, clearly defining the flow pattern in PC boilers is important for solving the problem of tube failure caused by fly ash erosion. For this purpose, the cold air velocity technique (CAVT) can be applied to the fly ash erosion problem. In this study, CAVT was carried out on the Hadong 2 PC boiler and the feasibility of application of CAVT to conventional PC boilers was validated

  20. Development of a ten inch manipulators-based, flexible, broadband two-crystal spectrometer.

    Science.gov (United States)

    Steel, A B; Dunn, J; Emig, J; Beiersdorfer, P; Brown, G V; Shepherd, R; Marley, E V; Hoarty, D J

    2014-11-01

    We have developed and implemented a broadband X-ray spectrometer with a variable energy range for use at the Atomic Weapons Establishment's Orion Laser. The spectrometer covers an energy bandwidth of ∼1-2 keV using two independently mounted, movable Bragg diffraction crystals. Using combinations of cesium hydrogen pthlate, ammonium dihydrogen phosphate, and pentaerythritol crystals, spectra covering the 1.4-2.5, 1.85-3.15, or 3.55-5.1 keV energy bands have been measured. Image plate is used for detection owing to its high dynamic range. Background signals caused by high energy X-rays and particles commonly produced in high energy laser experiments are reduced by a series of tantalum baffles and filters installed between the source and crystal and also between the crystals and detector.

  1. Two-phase anaerobic digestion for biogas production from dairy effluent—CSTR and ABR in series

    DEFF Research Database (Denmark)

    Jürgensen, L.; Ehimen, E. A.; Born, J.

    2016-01-01

    Anaerobic digestion of low-strength dairy waste water has been used for the production of biogas. A two-phase pilot scale process had been established within 90 d using a 1 m3continuous stirred tank reactor (CSTR) and a 200 l anaerobic baffled reactor (ABR) in series. The system was fed at constant...... retention time of 1.6 d and with changing feed strengths resulting in various organic loading rates between 1.25-4.50 g/(l d). The average COD removal was 82% with a biogas yield of 0.26 l/gCOD. The combination of CSTR and ABR overcame the disadvantages of both reactor types. By further optimization...... the chosen system is able to replace conventional waste water treatment system used nowadays....

  2. Intermediate heat exchanger tube vibration induced by cross and parallel mixed flow

    International Nuclear Information System (INIS)

    Kawamura, Koji

    1986-01-01

    The characteristics of pool type LMFBR intermediate heat exchanger (IHX) tube vibrations induced by cross and parallel mixed flow were basically investigated. Secondary coolant in IHX tube bundle is mixed flow of parallel jit flow along the tube axis through flow holes in baffle plates and cross flow. By changing these two flow rate, flow distributions vary in the tube bundle. Mixed flow also induces vibrations which cause fretting wear and fatigue of tube. It is therefore very important to evaluate the tube vibration characteristics for estimating the tube integrity. The results show that the relationships between tube vibrations and flow distributions in the tube bundle were cleared, and mixed flow induced tube vibration could be evaluated on the base of the characteristics of both parallel and cross flow induced vibration. From these investigations it could be concluded that the characteristics of tube vibration for various flow distributions can be systematically evaluated. (author)

  3. Before the beginning our universe and others

    CERN Document Server

    Rees, Martin

    1997-01-01

    "Although we cannot observe them (and they may be forever inaccessible), other universes are a natural expectation from current cosmology. Moreover, many features of our universe that otherwise seem baffling fall into place once we recognize this." Sir Martin Rees, the British Astronomer Royal, gives a vivid, occasionally acid tour of current astrophysics and cosmology, with insights into scientific politics, such as the enormous increase in the cost of the space telescope because of its association with the Space Shuttle. He also offers keen observations on personalities such as Subrahmayan Chandrasekhar and Isaac Newton, Yakov Zeldovich and Albert Einstein. Joseph Silk calls Before the Beginning "an unusual blend of wit, asperity and cosmology ... a combination of clarity and conciseness."

  4. Parametric Optimization of Ares I Propellant Slosh Characteristics Using Frequency Response Criteria

    Science.gov (United States)

    Orr, Jeb S.; Hall, Charles E.

    2009-01-01

    A novel technique for developing propellant slosh damping requirements with respect to the stability characteristics of large flexible launch vehicles is presented. A numerical algorithm is devised which allows an automated software program to rapidly converge to pseudo-optimal solutions that minimize required propellant slosh damping for multiple tanks while maintaining constraints on the frequency response characteristics of a particular open-loop plant transfer function. An implementation of the algorithm using a high-order linear model of the Ares I plant dynamics considers all relevant dynamic interactions of flexible body modes, propellant slosh, and nozzle inertia effects. A high-resolution propellant damping requirements table is produced that can be used for baffle design. The method is demonstrated to provide exceptional speed and accuracy when compared with the alternative human-in-the-loop approach.

  5. Super Phenix 1: in Service inspection of main and safety tanks weldments

    International Nuclear Information System (INIS)

    Asty, Michel; Vertut, Jean; Argous, J.P.

    1980-05-01

    In service inspection of the main tank of the Super Phenix 1 reactor is a new demand as compared to Phenix: the authorities have asked that surface and internal defects could be detected and their evolution monitored in the future. The presence of thermal baffles inside the main tank precludes the access on that side: the distance between the main and safety tanks takes into account the room needed for an In Service Inspection module. An inspection vehicle is presently under development, which includes ultrasonic examination (focussed probes) and visual examination (TV cameras) capabilities. We briefly describe the techniques that have been selected for ultrasonic testing and also for the vehicle and its guidance between the tanks

  6. A 100 keV operation of a large vacuum-immersed H - ion source

    Science.gov (United States)

    Oka, Y.; Kaneko, O.; Takeiri, Y.; Tsumori, K.; Ando, A.; Asano, E.; Akiyama, R.; Kawamoto, T.; Kuroda, T.

    1996-03-01

    A large vacuum-immersed H- ion source has been operated on the negative-ion-based neutral beam teststand. The achieved level of the beam and the pulse duration in beam conditioning were limited by a high-voltage breakdown in the vacuum vessel. A baffle plate at grounded potential for shielding completely from the charged particles was successful. A beam with an energy of up to 102 keV and the H- ion current of 0.55 A were achieved for 0.29 s without the breakdown. The ion current of ˜1.5 A was accelerated in cesium-seeded operation. The corresponding ion current density was ˜7 mA/cm2. A magnetic filter (as Type I LV magnetic filter) on the plasma electrode was applied. The electron beam component which was extracted from the plasma source together with H- ions was found to be very reduced.

  7. Intensity of convective mass/heat transfer in a rotary regenerator rotor with the transverse needle-fins

    Science.gov (United States)

    Bieniasz, Bogumił

    2014-09-01

    A forced convective mass transfer coefficient was electrochemically measured for a cylindrical bundle of transverse needle-fins ϕ1 × 10.9, applied as the rotor porous matrix of a rotary heat regenerator. The baffle inside the rotor was present. The technique based on the ferricyanide-ferrocyanide redox reaction controlled at the cathode, in the presence of a sodium hydroxide based electrolyte, was used in this experiment. A set of the six neighbouring fins, connected in parallel, was the cathode. The distribution of the mass transfer coefficient according to different static rotor angle position and the mean mass transfer Chilton-Colburn coefficient correlation j M = j M ( Re) for rotation numbers, Ro: 0, 0.8, 1.6 and 2.0 were stated in the mean Reynolds number, Re, range 180-985. The comparison was made between the convective heat fluxes of the pin-fins and the sheet rotor, for Ro = 0.

  8. Rocky Flats Plant Live-Fire Range Risk Analysis Report

    Energy Technology Data Exchange (ETDEWEB)

    Nicolosi, S.L.; Rodriguez, M.A.

    1994-04-01

    The objective of the Live-Fire Range Risk Analysis Report (RAR) is to provide an authorization basis for operation as required by DOE 5480.16. The existing Live-Fire Range does not have a safety analysis-related authorization basis. EG&G Rocky Flats, Inc. has worked with DOE and its representatives to develop a format and content description for development of an RAR for the Live-Fire Range. Development of the RAR is closely aligned with development of the design for a baffle system to control risks from errant projectiles. DOE 5480.16 requires either an RAR or a safety analysis report (SAR) for live-fire ranges. An RAR rather than a SAR was selected in order to gain flexibility to more closely address the safety analysis and conduct of operation needs for a live-fire range in a cost-effective manner.

  9. The forced sound transmission of finite ribbed plates, investigating the influence of point connections and periodicity

    DEFF Research Database (Denmark)

    Brunskog, Jonas

    2015-01-01

    of the structure. These types of structures have thus often been studied in the past. However, there is still a lack of simplified expressions for the sound transmission of these structures. Therefore, simplified expressions for the forced airborne sound transmission of finite size single leaf ribbed plates have......Many engineering structures consist of plates being stiffened by ribs. The ribs can be connected to the plate in a line connection (welded or glued) or in point connections (screwed). It is well known that the rib stiffeners can significantly change the vibration field and the radiation behavior...... been derived, using a variational technique based on integral-differential equations of the fluid loaded plate. In this way an optimal solution is derived, using a very simple initial guess of the vibration field. The finite plate is assumed being mounted in a rigid baffle. The approach is based...

  10. Quantum

    CERN Document Server

    Al-Khalili, Jim

    2003-01-01

    In this lively look at quantum science, a physicist takes you on an entertaining and enlightening journey through the basics of subatomic physics. Along the way, he examines the paradox of quantum mechanics--beautifully mathematical in theory but confoundingly unpredictable in the real world. Marvel at the Dual Slit experiment as a tiny atom passes through two separate openings at the same time. Ponder the peculiar communication of quantum particles, which can remain in touch no matter how far apart. Join the genius jewel thief as he carries out a quantum measurement on a diamond without ever touching the object in question. Baffle yourself with the bizzareness of quantum tunneling, the equivalent of traveling partway up a hill, only to disappear then reappear traveling down the opposite side. With its clean, colorful layout and conversational tone, this text will hook you into the conundrum that is quantum mechanics.

  11. Large-area beryllium metal foils

    Science.gov (United States)

    Stoner, J. O., Jr.

    1997-02-01

    To manufacture beryllium filters having diameters up to 82 mm and thicknesses in the range 0.1-1 μm, it was necessary to construct apparatus in which the metal could safely be evaporated, and then to find an acceptable substrate and evaporation procedure. The metal was evaporated resistively from a tantalum dimple boat mounted in a baffled enclosure that could be placed in a conventional vacuum bell jar, obviating the need for a dedicated complete vacuum system. Substrates were 102 mm × 127 mm × 0.05 mm cleaved mica sheets, coated with 0.1 μm of NaCl, then with approximately 50 μg/cm 2 of cellulose nitrate. These were mounted on poly(methyl methacrylate) sheets 3 mm thick that were in turn clamped to a massive aluminum block for thermal stability. Details of the processes for evaporation, float off, and mounting are given, and the resulting foils described.

  12. Characterization, origin and hierarchy of lateral shale-barriers in the Petrocedeno heavy oil field, Orinoco oil belt, Venezuela

    Energy Technology Data Exchange (ETDEWEB)

    Hegner, J. [Petrocedeno, Total E and P (Venezuela); Bejarano, C. [Petrocedeno, PDVSA, CVP (Venezuela)

    2011-07-01

    The Petrocedeno heavy oil field located in the western part of the Orinoco oil belt, Venezuela, is in its last stages of primary recovery with over 10 years of production and enhanced oil recovery (EOR) projects are now being considered. A better reservoir characterization is required to implement those EOR projects and thus the aim of the study is to improve understanding of the reservoir barriers and baffles. Based on available data, core description and wire-line pressure depletion data from the Petrocedeno field, a shale barrier model was developed. It was found that thick mudstone may provide shale barriers and interact with production. In addition a hierarchy for the Petrocedeno area was proposed. This study provided a better understanding of shale barriers in the Petrocedeno heavy oil field but further research should be undertaken to refine the recognition of shale origin.

  13. Straylight analysis of the BepiColombo Laser Altimeter

    Science.gov (United States)

    Weigel, T.; Rugi-Grond, E.; Kudielka, K.

    2008-09-01

    The BepiColombo Laser Altimeter (BELA) shall profile the surface of planet Mercury and operates on the day side as well as on the night side. Because of the high thermal loads, most interior surfaces of the front optics are highly reflective and specular, including the baffle. This puts a handicap on the straylight performance, which is needed to limit the solar background. We present the design measures used to reach an attenuation of about 10-8. We resume the method of backward straylight analysis which starts the rays at the detector and analyses the results in object space. The backward analysis can be quickly compiled and challenges computer resources rather than labor effort. This is very useful in a conceptual design phase when a design is iterated and trade-offs are to be performed. For one design, we compare the results with values obtained from a forward analysis.

  14. Diagnosing the tight building syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, S.A.

    1987-12-01

    Formaldehyde is but one of many chemicals capable of causing the tight building syndrome or environmentally induced illness (EI). The spectrum of symptoms it may induce includes attacks of headache, flushing, laryngitis, dizziness, nausea, extreme weakness, arthralgia, unwarranted depression, dysphonia, exhaustion, inability to think clearly, arrhythmia or muscle spasms. The nonspecificity of such symptoms can baffle physicians from many specialties. Presented herein is a simple office method for demonstrating that formaldehyde is among the etiologic agents triggering these symptoms. The very symptoms that patients complain of can be provoked within minutes, and subsequently abolished, with an intradermal injection of the appropriate strength of formaldehyde. This injection aids in convincing the patient of the cause of the symptoms so he can initiate measure to bring his disease under control.

  15. Preliminary assessment of the tritium inventory and permeation in the plasma facing components of ITER

    International Nuclear Information System (INIS)

    Federici, G.; Holland, D.; Brooks, J.; Causey, R.; Dolan, T.J.; Longhurst, G.

    1995-01-01

    This paper discusses preliminary quantitative predictions for the tritium inventory in- and permeation through the first-wall and divertor PFC's of ITER. The primary plasma facing material under consideration is beryllium, with possible use of tungsten or carbon fiber composites (CFC's) on high-heat-flux surfaces. They use state-of-the-art tritium transport models, in conjunction with design parameters, and loading conditions anticipated for the first-wall, baffle, limiter and divertor. The analysis includes the synergistic effects of erosion on tritium implantation and trapping, which are expected to play a key role, particularly in the divertor regions where the interaction of the plasma with the surfaces will be most severe. The influence of several key parameters that strongly affect tritium build-up and release is assessed. Finally, they discuss the uncertainties in materials properties under ITER operating conditions and the R and D needed to resolve these uncertainties

  16. Design And Performance Analysis Of The Claes NE/CO2 Cryostat

    Science.gov (United States)

    Naes, L. G.; Horsley, W. J.; Ngai, C. S.; Read, D. C.; Nast, T. C.

    1988-04-01

    The Cryogenic Limb Array Etalon Spectrometer (CLAES)1 is one of nine instruments that will fly aboard the Upper Atmospheric Research Satellite (UARS)2 in the fall of 1991. CLAES is an earth-limb viewing instrument that requires cryogenic cooling of its focal plane (Challenger shuttle disaster, the UARS and CLAES Project Offices investigated the feasibility of incorporating a completely inert cryogen system for CLAES. The result of this study showed that a dual stage Ne/CO2 cryostat would meet all sensor cooling requirements, provided that a significant increase in weight could be accommodated. In December '86, the Ne/CO2 design was adopted as the new cryostat baseline for CLAES. The focal plane and spectrometer are conductively cooled to the solid neon (13.2 K) while the telescope and internal baffles are cooled by the CO2 (121.8K). This paper describes the design and performance of the Ne/CO2 cryostat.

  17. Overview of the EU small scale mock-up tests for ITER high heat flux components

    International Nuclear Information System (INIS)

    Vieider, G.; Barabash, V.; Cardella, A.

    1998-01-01

    This task within the EU R and D for ITER was aimed at the development of basic manufacturing solutions for the high heat flux plasma facing components such as the divertor targets, the baffles and limiters. More than 50 representative small-scale mock-ups have been manufactured with beryllium, carbon and tungsten armour using various joining technologies. High heat flux testing of 20 of these mock-ups showed the carbon mono-blocks to be the most robust solution, surviving 2000 cycles at absorbed heat fluxes of up to 24 MW m -2 . With flat armour tiles rapid joint failures occurred at 5-16 MW m -2 depending on joining technology and armour material. These test results serve as a basis for the selection of manufacturing options and materials for the prototypes now being ordered. (orig.)

  18. MERCHANT MARINE SHIP REACTOR

    Science.gov (United States)

    Mumm, J.F.; North, D.C. Jr.; Rock, H.R.; Geston, D.K.

    1961-05-01

    A nuclear reactor is described for use in a merchant marine ship. The reactor is of pressurized light water cooled and moderated design in which three passes of the water through the core in successive regions of low, intermediate, and high heat generation and downflow in a fuel region are made. The foregoing design makes a compact reactor construction with extended core life. The core has an egg-crate lattice containing the fuel elements confined between a lower flow baffle and upper grid plate, with the latter serving also as part of a turn- around manifold from which the entire coolant is distributed into the outer fuel elements for the second pass through the core. The inner fuel elements are cooled in the third pass.

  19. REACTOR SHIELD

    Science.gov (United States)

    Wigner, E.P.; Ohlinger, L.E.; Young, G.J.; Weinberg, A.M.

    1959-02-17

    Radiation shield construction is described for a nuclear reactor. The shield is comprised of a plurality of steel plates arranged in parallel spaced relationship within a peripheral shell. Reactor coolant inlet tubes extend at right angles through the plates and baffles are arranged between the plates at right angles thereto and extend between the tubes to create a series of zigzag channels between the plates for the circulation of coolant fluid through the shield. The shield may be divided into two main sections; an inner section adjacent the reactor container and an outer section spaced therefrom. Coolant through the first section may be circulated at a faster rate than coolant circulated through the outer section since the area closest to the reactor container is at a higher temperature and is more radioactive. The two sections may have separate cooling systems to prevent the coolant in the outer section from mixing with the more contaminated coolant in the inner section.

  20. Control of long range turbulent transport with biasing in the tokamak scrape-off-layer

    International Nuclear Information System (INIS)

    Figarella, C.F.; Ghendrih, Ph.; Sarazin, Y.; Attuel, G.; Benkadda, S.; Beyer, P.; Falchetto, G.; Fleurence, E.; Garbet, X.; Grandgirard, V.

    2005-01-01

    Cross-field transport in the SOL influences tokamak performance in particular regarding the divertor efficiency. Recent experiment evidence emphasizes non-exponential and/or flat SOL profiles that suggest a large perpendicular transport. A 2D fluid model based on the interchange instability to simulate the SOL turbulence was found to exhibits intermittent dynamics of the particle flux. We propose a control method that prevents long range transport events from reaching the far SOL: It consists in biasing the far SOL leading to a transport barrier which stops the propagation of these intermittent events. The best trade off is to localize the biased toroidal ring around the baffles. We show that such a control is achievable providing the strength of the barrier is strong enough. The investigation of the minimal biasing power required to achieve the control as well as its experimental estimate is performed

  1. A links manipulator simulation program interim report

    International Nuclear Information System (INIS)

    Noble, R.A.

    1987-04-01

    A computer program to simulate the performance of the Heysham II rail-following manipulator has been developed. The program is being used to develop and test the rail-following control algorithms which will be used to control movements of the manipulator when it is operating below the gas baffle dome. The simulation includes the dynamic responses of the manipulator joint drives, excluding friction, backlash and compliance. It also includes full details of the manipulator's geometry. A method is given whereby the actual manipulator dynamics can be written into the program once these have been established by measurement. The program is written in FORTRAN and runs on a Perkin-Elmer 3220 mini-computer. The simulation program responds to velocity demands on the individual joints. These will normally come from the control program, in which they will be manually controlled by a joystick. A sigma 5664 colour graphics generator is programmed to display the current position of the manipulator. (UK)

  2. Clementine sensor suite

    Energy Technology Data Exchange (ETDEWEB)

    Ledebuhr, A.G. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    LLNL designed and built the suite of six miniaturized light-weight space-qualified sensors utilized in the Clementine mission. A major goal of the Clementine program was to demonstrate technologies originally developed for Ballistic Missile Defense Organization Programs. These sensors were modified to gather data from the moon. This overview presents each of these sensors and some preliminary on-orbit performance estimates. The basic subsystems of these sensors include optical baffles to reject off-axis stray light, light-weight ruggedized optical systems, filter wheel assemblies, radiation tolerant focal plane arrays, radiation hardened control and readout electronics and low mass and power mechanical cryogenic coolers for the infrared sensors. Descriptions of each sensor type are given along with design specifications, photographs and on-orbit data collected.

  3. CFD Study of Fluid Flow in an All-glass Evacuated Tube Solar Water Heater

    DEFF Research Database (Denmark)

    Ai, Ning; Fan, Jianhua; Li, Yumin

    2008-01-01

    , which decreases efficiency of the heat exchange process. A baffle in the tube can prevent the flow instability and secure the flow circulation in the tube. The results of the investigation provide a helpful guidance for further investigation of the mechanism of heat transfer processes and a reference......Abstract: The all-glass evacuated tube solar water heater is one of the most widely used solar thermal technologies. The aim of the paper is to investigate fluid flow in the solar water heater by means of computational fluid dynamics (CFD). The investigation was carried out with a focus...... on the convective heat transfer in the tube. The buoyancy induced flow circulation in different parts of the tube was analyzed. It is shown that fluid flow becomes stochastic and turbulent if fluid temperature is high enough. The flow instability leads to mixing of the warm uprising flow and the cold downward flow...

  4. A new approach to calculating spatial impulse responses

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt

    1997-01-01

    Using linear acoustics the emitted and scattered ultrasound field can be found by using spatial impulse responses as developed by Tupholme (1969) and Stepanishen (1971). The impulse response is calculated by the Rayleigh integral by summing the spherical waves emitted from all of the aperture...... of the emitting aperture. Summing the angles of the arcs within the aperture readily yields the spatial impulse response for a point in space. The approach makes is possible to make very general calculation routines for arbitrary, flat apertures in which the outline of the aperture is either analytically...... be used for finding analytic solutions to the spatial impulse response for new geometries of, for example, ellipsoidal shape. The approach also makes it easy to incorporate any apodization function and the effect from different transducers baffle mountings. Examples of spatial impulse responses...

  5. Ceramics and healthy heating and cooling systems: thermal ceramic panels in buildings. Conditions of comfort and energy demand versus convective systems

    Directory of Open Access Journals (Sweden)

    V. Echarri Iribarren

    2016-12-01

    Full Text Available Porcelain stoneware is a widely used building material. In recent years, its range of uses has expanded to encompass a new spectrum of innovative and inventive applications in architecture. In this research, we analysed the patented Thermal Ceramic Panel. This consists of a thin porcelain stoneware panel that incorporates a capillary system of polypropylene tubes measuring 3.5 mm in diameter embedded in a conductive ceramic interface. The system works with hot or cold water, producing healthy heating and cooling by means of radiant surfaces. Following an initial prototype test in which panels were placed on the walls of an office, we conducted simulations at the University of Alicante Museum using wall, ceiling and baffle panels, having previously monitored the state of the building. Thermal behaviour parameters were analysed and compared with those of other standard finishing materials, obtaining results for thermal comfort and energy savings in comparison with all-air systems.

  6. Effect of pH on lead removal from water using tree fern as the sorbent.

    Science.gov (United States)

    Ho, Yuh-Shan

    2005-07-01

    The sorption of lead from water onto an agricultural by-product, tree fern, was examined as a function of pH. The sorption processes were carried out using an agitated and baffled system. Pseudo-second-order kinetic analyses were performed to determine the rate constant of sorption, the equilibrium sorption capacity, and the initial sorption rate. Application of the pseudo-second-order kinetics model produced very high coefficients of determination. Results showed the efficiency of tree fern as a sorbent for lead. The optimum pH for lead removal was between 4 and 7, with pH 4.9 resulting in better lead removal. Ion exchange occurred in the initial reaction period. In addition, a relation between the change in the solution hydrogen ion concentration and equilibrium capacity was developed and is presented.

  7. CEGB intergraph computer aided design system as an aid for the navigation of remote manipulators

    International Nuclear Information System (INIS)

    Lichnowski, A.J.M.; Hopton, G.

    1988-01-01

    Computer Aided Design Systems with 3D Graphic capability can offer substantial benefits for the simulation and navigation of remote manipulators. The CEGB has been experimenting with its own Corporate INTERGRAPH CAD Network using as an example a remote links manipulator working within the above gas baffle dome area of an Advanced Gas Cooled Reactor. A report of this work is presented together with graphic simulations of the manipulator within the above dome area and reconstructions of images anticipated from the on board cameras. Future improvements in the speed of graphic processing will enable these techniques to be used for the on-line navigation of manipulators, as an aid to the interpretation of video images and for the training of operators without the need for full size test and training facilities. (author)

  8. Premixing direct injector

    Science.gov (United States)

    Johnson, Thomas Edward [Greer, SC; Stevenson, Christian Xavier [Inman, SC; York, William David [Greer, SC; Ziminsky, Willy Steve [Simpsonville, SC

    2012-04-17

    A fuel injection nozzle comprises a body member having an upstream wall opposing a downstream wall, a baffle member having an upstream surface and a downstream surface, a first chamber, a second chamber, a fuel inlet communicative with the first chamber operative to emit a first gas into the first chamber, and a plurality of mixing tubes, each of the mixing tubes having a tube inner surface, a tube outer surface, a first inlet communicative with an aperture in the upstream wall operative to receive a second gas, a second inlet communicative with the tube outer surface and the tube inner surface operative to translate the first gas into the mixing tube, a mixing portion operative to mix the first gas and the second gas, and an outlet communicative with an aperture in the downstream wall operative to emit the mixed first and second gasses.

  9. Observing the stars. Love in the age of systems

    Directory of Open Access Journals (Sweden)

    Kjetil Ansgar Jakobsen

    2010-11-01

    Full Text Available A number of scholars have demonstrated how the cultural industry involves people in a participatory culture in which users actively construct personal identities. However, the link between a public of mass-mediated entertainment and the private sphere of intimacy and personal identity is a paradox. A consistent theory to clarify that paradox is lacking in the cultural studies literature. I suggest that social systems theory in the Luhmannian tradition may explain in economical terms why the continuous performance and intensification of the paradox of mass-mediated intimacy is a major trait of contemporary culture. Nevertheless, the article does not address normative issues. It is neither an apology for the culture industry, nor a condemnation. The aim is simply to bring one of the most powerful tools of analysis in social theory today to bear on an aspect of modern society which is as important as it is baffling.

  10. Perencanaan SPAL dan IPAL Komunal di Kabupaten Ngawi (Studi Kasus Perumahan Karangtengah Prandon, Perumahan Karangasri dan Kelurahan Karangtengah

    Directory of Open Access Journals (Sweden)

    Azimah Ulya

    2014-09-01

    Full Text Available Kabupaten Ngawi mempunyai rencana untuk meningkatkan kondisi sanitasi di daerahnya. Salah satu caranya dengan membangun IPAL komunal di tiga titik. Hal tersebut dikarenakan selama ini masih belum mempunyai IPAL komunal untuk limbah domestiknya. Tiga titik yang dimaksud adalah perumahan Karangtengah Prandon, perumahan Karangsari dan kelurahan Karangtengah. Lokasi itu dipilih karena termasuk kawasan yang ODF (Open Defecation Free. Sistem penyaluran air limbah untuk 3 lokasi perumahan ini menggunakan sistem shallow sewer yaitu air limbah domestik dari alat saniter (jamban, wastafel, floor drain, kitchen sink dll langsung dihubungkan menggunakan pipa air limbah dan sistem penyaluran air limbah pada perencanaan ini menggunakan sistem gravitasi. Dimensi pipa yang digunakan adalah 100 mm untuk air limbah dari pipa service dan 150 mm untuk saluran pipa induk menuju ke IPAL. IPAL komunal yang digunakan adalah ABR (Anaerobic Baffled Reactor dengan 6 kompartemen tiap ABR.

  11. Why Do Markets Crash? Bitcoin Data Offers Unprecedented Insights

    Science.gov (United States)

    Donier, Jonathan; Bouchaud, Jean-Philippe

    2015-01-01

    Crashes have fascinated and baffled many canny observers of financial markets. In the strict orthodoxy of the efficient market theory, crashes must be due to sudden changes of the fundamental valuation of assets. However, detailed empirical studies suggest that large price jumps cannot be explained by news and are the result of endogenous feedback loops. Although plausible, a clear-cut empirical evidence for such a scenario is still lacking. Here we show how crashes are conditioned by the market liquidity, for which we propose a new measure inspired by recent theories of market impact and based on readily available, public information. Our results open the possibility of a dynamical evaluation of liquidity risk and early warning signs of market instabilities, and could lead to a quantitative description of the mechanisms leading to market crashes. PMID:26448333

  12. Cryogenic and thermal design for the Space Infrared Telescope Facility (SIRTF)

    Science.gov (United States)

    Lee, J. H.; Brooks, W. F.

    1984-01-01

    The 1-meter class cryogenically cooled Space Infrared Telescope Facility (SIRTF) planned by NASA, is scheduled for a 1992 launch. SIRTF would be deployed from the Shuttle, and placed into a sun synchronous polar orbit of 700 km. The facility has been defined for a mission with a minimum initial lifetime of one year in orbit with mission extension that could be made possible through in-orbit servicing of the superfluid helium cryogenic system, and use of a thermal control system. The superfluid dewar would use an orbital disconnect system for the tank supports, and vapor cooling of the barrel baffle. The transient analysis of the design shows that the superfluid helium tank with no active feedback comes within temperature requirements for the nominal orbital aperture heat load, quiescent instrument, and chopper conditions.

  13. The quantum handshake entanglement, nonlocality and transactions

    CERN Document Server

    Cramer, John G

    2016-01-01

    This book shines bright light into the dim recesses of quantum theory, where the mysteries of entanglement, nonlocality, and wave collapse have motivated some to conjure up multiple universes, and others to adopt a "shut up and calculate" mentality. After an extensive and accessible introduction to quantum mechanics and its history, the author turns attention to his transactional model. Using a quantum handshake between normal and time-reversed waves, this model provides a clear visual picture explaining the baffling experimental results that flow daily from the quantum physics laboratories of the world. To demonstrate its powerful simplicity, the transactional model is applied to a collection of counter-intuitive experiments and conceptual problems.

  14. Development of a radiative divertor for DIII-D

    International Nuclear Information System (INIS)

    Allen, S.L.; Brooks, N.H.; Campbell, R.B.; Fenstermacher, M.E.; Hill, D.N.; Hyatt, A.W.; Knoll, D.; Lasnier, C.J.; Lazarus, E.A.; Leonard, A.W.; Lippmann, S.I.; Mahdavi, M.A.; Maingi, R.; Meyer, W.; Moyer, R.A.; Petrie, T.W.; Porter, G.D.; Rensink, M.E.; Rognlien, T.D.; Schaffer, M.J.; Smith, J.P.; Staebler, G.M.; Stambaugh, R.D.; West, W.P.; Wood, R.D.

    1995-01-01

    We have used experiments and modeling to develop a new radiative divertor configuration for DIII-D. Gas puffing experiments with the existing open divertor have shown the creation of a localized ( similar 10 cm diameter) radiation zone which results in substantial reduction (3-10) in the divertor heat flux while τ E remains similar 2 times ITER-89P scaling. However, n e increases with D 2 puffing, and Z eff increases with neon puffing. Divertor structures are required to minimize the effects on the core plasma. The UEDGE fluid code, benchmarked with DIII-D data, and the DEGAS neutrals transport code are used to estimate the effectiveness of divertor configurations; slots reduce the core ionization more than baffles. The overall divertor shape is set by confinement studies which indicate that high triangularity (δ∼0.8) is important for high τ E VH-modes. Results from engineering feasibility studies, including diagnostic access, will be presented. ((orig.))

  15. Design and economic investigation of shell and tube heat exchangers using Improved Intelligent Tuned Harmony Search algorithm

    Directory of Open Access Journals (Sweden)

    Oguz Emrah Turgut

    2014-12-01

    Full Text Available This study explores the thermal design of shell and tube heat exchangers by using Improved Intelligent Tuned Harmony Search (I-ITHS algorithm. Intelligent Tuned Harmony Search (ITHS is an upgraded version of harmony search algorithm which has an advantage of deciding intensification and diversification processes by applying proper pitch adjusting strategy. In this study, we aim to improve the search capacity of ITHS algorithm by utilizing chaotic sequences instead of uniformly distributed random numbers and applying alternative search strategies inspired by Artificial Bee Colony algorithm and Opposition Based Learning on promising areas (best solutions. Design variables including baffle spacing, shell diameter, tube outer diameter and number of tube passes are used to minimize total cost of heat exchanger that incorporates capital investment and the sum of discounted annual energy expenditures related to pumping and heat exchanger area. Results show that I-ITHS can be utilized in optimizing shell and tube heat exchangers.

  16. Investigation of microbial inactivation efficiency of a UV disinfection system employing an excimer lamp.

    Science.gov (United States)

    Naunovic, Zorana; Lim, Soojung; Blatchley, Ernest R

    2008-12-01

    An ultraviolet (UV) disinfection reactor based on excimer lamp technology was designed by integration of the results of numerical simulations based on computational fluid dynamics and a fluence rate (E') distribution model for cylindrical excimer lamps. The E' distribution model was developed based on a point source approach that accounts for absorption, dissipation, reflection, and refraction within the reactor system. A prototype reactor was constructed with a xenon-bromide excimer lamp and an internal spiral baffle. Experiments were conducted on the reactor to test its effectiveness for disinfection of drinking water in situations where the use of mercury-based UV sources is restricted or undesirable; a similar design approach could be used to develop an excimer UV reactor for disinfection of other fluid media, including wastewater or air.

  17. Rirang Uranium Ore Processing System Design: Designing A Quencher Unit: A Continuous Quencher Has Been Designed

    International Nuclear Information System (INIS)

    Effendi, Amir; Lisa Nuri, Hafni

    1996-01-01

    The objective of the design is to make a laboratory scale quencher model that is used to facilitate the dissolution and sudden cooling of the digestion product of the Rirang ore. The designed quencher was based on the previous batch quenching data, feed capacity of 325 g/minute, and residence time of one and two hours for quenching tank and thickener, respectively. The cylindrical quenching tank has dimension of 30 cm diameter and 30 cm high. It has three 2,5 cm baffles and is equipped with a blade-impeller agitator. The bottom-pitched cylindrical thickener has the diameter of 56 cm. The thickener is divided into four zones including clarification, feed; critical, and compression with 5, 3, 3, and 4 cm zones height, respectively. In addition, the bottom pitch has 12,5 cm height. The quencher model is further used to conduct performance test against Rirang ore digestion product

  18. Recent results on cleaning and conditioning the ATF vacuum system

    International Nuclear Information System (INIS)

    Langley, R.A.; Clark, T.L.; Glowienka, J.C.

    1989-01-01

    Techniques for cleaning and conditioning the vacuum vessel of the Advanced Toroidal Facility (ATF) and its internal components are described. The vacuum vessel cleaning technique combines baking to 150/degree/C and glow discharges with hydrogen gas. Chromium gettering is used to further condition the system. The major internal components are the anodized aluminum baffles in the Thomson scattering system, a graphite-shielded ICRF antenna, two graphite limiters, and a diagnostic graphite plate. Three independent heating systems are used to bake some of the major components of the system. The major characteristics used for assessing cleanliness and conditioning progress are the maximum pressure attained during bakeout, the results of gas analysis, and relevant plasma parameters (e.g., time to radiative decay). Details of the various cleaning and conditioning procedures and results are presented. 5 refs., 8 figs., 3 tabs

  19. Space shuttle aps propellant thermal conditioner study

    Science.gov (United States)

    Fulton, D. L.

    1973-01-01

    An analytical and experimental effort was completed to evaluate a baffle type thermal conditioner for superheating O2 and H2 at supercritical pressures. The thermal conditioner consisted of a heat exchanger and an integral reactor (gas generator) operating on O2/H2 propellants. Primary emphasis was placed on the hydrogen conditioner with some effort on the oxygen conditioner and a study completed of alternate concepts for use in conditioning oxygen. A hydrogen conditioner was hot fire tested under a range of conditions to establish ignition, heat exchange and response parameters. A parallel technology task was completed to further evaluate the integral reactor and heat exchanger with the side mounted electrical spark igniter.

  20. Grammar in art.

    Science.gov (United States)

    Segel, Edward; Boroditsky, Lera

    2010-01-01

    Jakobson (1959) reports: "The Russian painter Repin was baffled as to why Sin had been depicted as a woman by German artists: he did not realize that 'sin' is feminine in German (die Sünde), but masculine in Russian (rpex)." Does the grammatical gender of nouns in an artist's native language indeed predict the gender of personifications in art? In this paper we analyzed works in the ARTstor database (a digital art library containing over a million images) to measure this correspondence. This analysis provides a measure of artists' real-world behavior. Our results show a clear correspondence between grammatical gender in language and personified gender in art. Grammatical gender predicted personified gender in 78% of the cases, significantly more often than if the two factors were independent. This analysis offers a new window on an age-old question about the relationship between linguistic structure and patterns in culture and cognition.