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Sample records for pseudo film boiling

  1. Low-Flow Film Boiling Heat Transfer on Vertical Surfaces

    DEFF Research Database (Denmark)

    Munthe Andersen, J. G.; Dix, G. E.; Leonard, J. E.

    1976-01-01

    The phenomenon of film boiling heat transfer for high wall temperatures has been investigated. Based on the assumption of laminar flow for the film, the continuity, momentum, and energy equations for the vapor film are solved and a Bromley-type analytical expression for the heat transfer...... length, an average film boiling heat transfer coefficient is obtained....

  2. Study of film boiling collapse behavior during vapor explosion

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, Masahiro; Yamano, Norihiro; Sugimoto, Jun [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Abe, Yutaka; Adachi, Hiromichi; Kobayashi, Tomoyoshi

    1996-06-01

    Possible large scale vapor explosions are safety concern in nuclear power plants during severe accident. In order to identify the occurrence of the vapor explosion and to estimate the magnitude of the induced pressure pulse, it is necessary to investigate the triggering condition for the vapor explosion. As a first step of this study, scooping analysis was conducted with a simulation code based on thermal detonation model. It was found that the pressure at the collapse of film boiling much affects the trigger condition of vapor explosion. Based on this analytical results, basic experiments were conducted to clarify the collapse conditions of film boiling on a high temperature solid ball surface. Film boiling condition was established by flooding water onto a high temperature stainless steel ball heated by a high frequency induction heater. After the film boiling was established, the pressure pulse generated by a shock tube was applied to collapse the steam film on the ball surface. As the experimental boundary conditions, materials and size of the balls, magnitude of pressure pulse and initial temperature of the carbon and stainless steel balls were varied. The transients of pressure and surface temperature were measured. It was found that the surface temperature on the balls sharply decreased when the pressure wave passed through the film on balls. Based on the surface temperature behavior, the film boiling collapse pattern was found to be categorized into several types. Especially, the pattern for stainless steel ball was categorized into three types; no collapse, collapse and reestablishment after collapse. It was thus clarified that the film boiling collapse behavior was identified by initial conditions and that the pressure required to collapse film boiling strongly depended on the initial surface temperature. The present results will provide a useful information for the analysis of vapor explosions based on the thermal detonation model. (J.P.N.)

  3. Intensive cooling metallic bodies with low thermal conductivity in film boiling of ethanol

    Science.gov (United States)

    Zabirov, A. R.; Yagov, V. V.; Kanin, P. K.

    2017-10-01

    Film boiling regime occurs when temperature of solid surface exceeds the attainable limiting temperature of the cooling liquid. In unsteady conditions, this boiling regime has applications in safety systems of Nuclear Power Plants (NPP) and in metal-processing. Nonsteady film boiling of subcooled water has unresolved issues relating to the conditions when low-intensive stable film boiling regime turns to a high intensive mode. The present paper considers the new experimental results on unsteady film boiling of ethanol over a wide range of subcoolings. On the basis of the experimental data, a hypothesis has been developed to explain appearance of the intensive heat transfer during film boiling.

  4. Boils

    Science.gov (United States)

    ... or recurrent boils, which are usually due to Staph infections. The bacteria are picked up somewhere and ... is an infection of hair follicles, usually with Staph bacteria. These often itch more than hurt. The ...

  5. A pseudo-single-crystalline germanium film for flexible electronics

    Energy Technology Data Exchange (ETDEWEB)

    Higashi, H.; Yamada, S.; Kanashima, T.; Hamaya, K., E-mail: hamaya@ee.es.osaka-u.ac.jp [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Kasahara, K.; Park, J.-H.; Miyao, M. [Department of Electronics, Kyushu University, 744 Motooka, Fukuoka 819-0395 (Japan); Kudo, K.; Okamoto, H.; Moto, K.; Tsunoda, I. [Kumamoto National College of Technology, 2659-2 Suya, Koshi, Kumamoto 861-1102 (Japan)

    2015-01-26

    We demonstrate large-area (∼600 μm), (111)-oriented, and high-crystallinity, i.e., pseudo-single-crystalline, germanium (Ge) films at 275 °C, where the temperature is lower than the softening temperature of a flexible substrate. A modulated gold-induced layer exchange crystallization method with an atomic-layer deposited Al{sub 2}O{sub 3} barrier and amorphous-Ge/Au multilayers is established. From the Raman measurements, we can judge that the crystallinity of the obtained Ge films is higher than those grown by aluminum-induced-crystallization methods. Even on a flexible substrate, the pseudo-single-crystalline Ge films for the circuit with thin-film transistor arrays can be achieved, leading to high-performance flexible electronics based on an inorganic-semiconductor channel.

  6. Modeling of Inverted Annular Film Boiling using an integral method

    Science.gov (United States)

    Sridharan, Arunkumar

    In modeling Inverted Annular Film Boiling (IAFB), several important phenomena such as interaction between the liquid and the vapor phases and irregular nature of the interface, which greatly influence the momentum and heat transfer at the interface, need to be accounted for. However, due to the complexity of these phenomena, they were not modeled in previous studies. Since two-phase heat transfer equations and relationships rely heavily on experimental data, many closure relationships that were used in previous studies to solve the problem are empirical in nature. Also, in deriving the relationships, the experimental data were often extrapolated beyond the intended range of conditions, causing errors in predictions. In some cases, empirical correlations that were derived from situations other than IAFB, and whose applicability to IAFB was questionable, were used. Moreover, arbitrary constants were introduced in the model developed in previous studies to provide good fit to the experimental data. These constants have no physical basis, thereby leading to questionable accuracy in the model predictions. In the present work, modeling of Inverted Annular Film Boiling (IAFB) is done using Integral Method. Two-dimensional formulation of IAFB is presented. Separate equations for the conservation of mass, momentum and energy are derived from first principles, for the vapor film and the liquid core. Turbulence is incorporated in the formulation. The system of second-order partial differential equations is integrated over the radial direction to obtain a system of integral differential equations. In order to solve the system of equations, second order polynomial profiles are used to describe the nondimensional velocity and temperatures. The unknown coefficients in the profiles are functions of the axial direction alone. Using the boundary conditions that govern the physical problem, equations for the unknown coefficients are derived in terms of the primary dependent variables

  7. Investigation of film boiling thermal hydraulics under FCI conditions. Results of a numerical study

    Energy Technology Data Exchange (ETDEWEB)

    Dinh, T.N.; Dinh, A.T.; Nourgaliev, R.R.; Sehgal, B.R. [Div. of Nuclear Power Safety Royal Inst. of Tech. (RIT), Brinellvaegen 60, 10044 Stockholm (Sweden)

    1998-01-01

    Film boiling on the surface of a high-temperature melt jet or of a melt particle is one of key phenomena governing the physics of fuel-coolant interactions (FCIs) which may occur during the course of a severe accident in a light water reactor (LWR). A number of experimental and analytical studies have been performed, in the past, to address film boiling heat transfer and the accompanying hydrodynamic aspects. Most of the experiments have, however, been performed for temperature and heat flux conditions, which are significantly lower than the prototypic conditions. For ex-vessel FCIs, high liquid subcooling can significantly affect the FCI thermal hydraulics. Presently, there are large uncertainties in predicting natural-convection film boiling of subcooled liquids on high-temperature surfaces. In this paper, research conducted at the Division of Nuclear Power Safety, Royal Institute of Technology (RIT/NPS), Stockholm, concerning film-boiling thermal hydraulics under FCI condition is presented. Notably, the focus is placed on the effects of (1) water subcooling, (2) high-temperature steam properties, (3) the radiation heat transfer and (4) mixing zone boiling dynamics, on the vapor film characteristics. Numerical investigations are performed using a novel CFD modeling concept named as the local-homogeneous-slip model (LHSM). Results of the analytical and numerical studies are discussed with respect to boiling dynamics under FCI conditions. (author)

  8. A study on the correlations development for film boiling heat transfer on spheres

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Yong Hoon; Baek, Won Pil; Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1998-12-31

    Film boiling is the heat transfer mechanism that can occurs when large temperature differences exist between a cold liquid and hot material. In the nuclear reactor safety analysis, film boiling has become an important issue in recent years. During severe accident, hot molten corium fall into relatively cool water, and fragment into spheres or sphere-like particles. If the steam explosion is triggered, the thermal energy of corlium is converted into the mechanical energy that can threaten the integrity of reactor vessel or reactor cavity. One of the important concerns in the heat transfer analysis during pre-mixing stage is the film boiling heat transfer between the corium and water/steam two-phase flow. Until now, considerable works on film boiling have been performed. However, there is no available correlation adequate for severe accident analysis. In this study, film boiling heat transfer correlations have been developed, and their applicable ranges have been enlarged and their prediction accuracy has been enhanced. 7 refs., 5 figs., 5 tabs. (Author)

  9. Verification of the IVA4 film boiling model with the data base of Liu and Theofanous

    Energy Technology Data Exchange (ETDEWEB)

    Kolev, N.I. [Siemens AG Unternehmensbereich KWU, Erlangen (Germany)

    1998-01-01

    Part 1 of this work presents a closed analytical solution for mixed-convection film boiling on vertical walls. Heat transfer coefficients predicted by the proposed model and experimental data obtained at the Royal Institute of Technology in Sweden by Okkonen et al are compared. All data predicted are inside the {+-}10% error band, with mean averaged error being below 4% using the slightly modified analytical solution. The solution obtained is recommended for practical applications. The method presented here is used in Part 2 as a guideline for developing model for film boiling on spheres. The new semi-empirical film boiling model for spheres used in IVA4 computer code is compared with the experimental data base obtained by Liu and Theofanous. The data are predicted within {+-}30% error band. (author)

  10. A molecular dynamics study on thin film liquid boiling characteristics under rapid linear boundary heating: Effect of liquid film thickness

    Science.gov (United States)

    Rabbi, Kazi Fazle; Tamim, Saiful Islam; Faisal, A. H. M.; Mukut, K. M.; Hasan, Mohammad Nasim

    2017-06-01

    This study is a molecular dynamics investigation of phase change phenomena i.e. boiling of thin liquid films subjected to rapid linear heating at the boundary. The purpose of this study is to understand the phase change heat transfer phenomena at nano scale level. In the simulation, a thin film of liquid argon over a platinum surface has been considered. The simulation domain herein is a three-phase system consisting of liquid and vapor argon atoms placed over a platinum wall. Initially the whole system is brought to an equilibrium state at 90 K and then the temperature of the bottom wall is increased to a higher temperature (250K) within a finite time interval. Four different liquid argon film thicknesses have been considered (3 nm, 4 nm, 5 nm and 6 nm) in this study. The boundary heating rate (40×109 K/s) is kept constant in all these cases. Variation in system temperature, pressure, net evaporation number, spatial number density of the argon region with time for different film thickness have been demonstrated and analyzed. The present study indicates that the pattern of phase transition may be significantly different (i.e. evaporation or explosive boiling) depending on the liquid film thickness. Among the four cases considered in the present study, explosive boiling has been observed only for the liquid films of 5nm and 6nm thickness, while for the other cases, evaporation take place.

  11. Theoretical and experimental study of inverted annular film boiling and regime transition during reflood transients

    Science.gov (United States)

    Mohanta, Lokanath

    The Loss of Coolant Accident (LOCA) is a design basis accident for light water reactors that usually determines the limits on core power. During a LOCA, film boiling is the dominant mode of heat transfer prior to the quenching of the fuel rods. The study of film boiling is important because this mode of heat transfer determines if the core can be safely cooled. One important film boiling regime is the so-called Inverted Annular Film Boiling (IAFB) regime which is characterized by a liquid core downstream of the quench front enveloped by a vapor film separating it from the fuel rod. Much research have been conducted for IAFB, but these studies have been limited to steady state experiments in single tubes. In the present work, subcooled and saturated IAFB are investigated using high temperature reflood data from the experiments carried out in the Rod Bundle Heat Transfer (RBHT) test facility. Parametric effects of system parameters including the pressure, inlet subcooling, and flooding rate on the heat transfer are investigated. The heat transfer behavior during transition to Inverted Slug Film Boiling (ISFB) regime is studied and is found to be different than that reported in previous studies. The effects of spacer grids on heat transfer in the IAFB and ISFB regimes are also presented. Currently design basis accidents are evaluated with codes in which heat transfer and wall drag must be calculated with local flow parameters. The existing models for heat transfer are applicable up to a void fraction of 0.6, i.e. in the IAFB regime and there is no heat transfer correlation for ISFB. A new semi-empirical heat transfer model is developed covering the IAFB and ISFB regimes which is valid for a void fraction up to 90% using the local flow variables. The mean absolute percentage error in predicting the RBHT data is 11% and root mean square error is 15%. This new semi-empirical model is found to compare well with the reflood data of FLECHT-SEASET experiments as well as data

  12. Experimental Study on Boiling Heat Transfer of Liquid Film Flow on a Structural Surface

    Science.gov (United States)

    Hirose, Koichi; Mizuno, Itsuo; Nakata, Daisuke; Ouchi, Masaki

    An experimental study on the boiling heat transfer characteristics of liquid films flowing downward along vertically positioned plane and constant curvature surface (CCS) with isolated fine cavities was conducted. The effects of structural surfaces were examined, comparing with the case of smooth plane. The main results of these experiments are summarized as follows; (1) In the case of structual plane surface, there are remarkable enhancements of heat transfer rate in the nucleate boiling region. (2) In the case of CCS, it takes large values of heatflux in the region which strongly governed by the surface evaporation. (3)CCS avoids effectively the occurrence of splitting of the liquid film into rivulets. This study aims to put practical use of the heat transfer enhancement for the evaporator of a two-phase closed thermosiphon.

  13. Heat transfer at boiling of R114/R21 refrigerants mixture film on microstructured surfaces

    Science.gov (United States)

    Volodin, O. A.; Pecherkin, N. I.; Pavlenko, A. N.; Zubkov, N. N.; Bityutskaya, Yu L.

    2017-10-01

    The paper presents the results of experimental study of heat transfer in the film flow of R114/R21 refrigerant mixture on the vertical thin-wall copper cylinders with microstructured outer surfaces. Microstructuring is made by the method of deforming cutting with subsequent rolling by a straight knurl roller along the fin tops. The pitch of micro-finning was 100 or 200 μm and height was 220 or 440 μm, respectively. The knurling pitch in both cases was 318 μm. The film Reynolds number was varied in the range of 300-1500. The heat flux density was step-by-step increased from zero to the values corresponding to the boiling crisis. It is shown that the heat transfer coefficients at nucleate boiling on the studied surfaces with microstructuring exceed the corresponding values for a smooth surface more than by 3 times, the critical heat flux increases more than twice.

  14. Physics of microstructures enhancement of thin film evaporation heat transfer in microchannels flow boiling

    Science.gov (United States)

    Bigham, Sajjad; Fazeli, Abdolreza; Moghaddam, Saeed

    2017-03-01

    Performance enhancement of the two-phase flow boiling heat transfer process in microchannels through implementation of surface micro- and nanostructures has gained substantial interest in recent years. However, the reported results range widely from a decline to improvements in performance depending on the test conditions and fluid properties, without a consensus on the physical mechanisms responsible for the observed behavior. This gap in knowledge stems from a lack of understanding of the physics of surface structures interactions with microscale heat and mass transfer events involved in the microchannel flow boiling process. Here, using a novel measurement technique, the heat and mass transfer process is analyzed within surface structures with unprecedented detail. The local heat flux and dryout time scale are measured as the liquid wicks through surface structures and evaporates. The physics governing heat transfer enhancement on textured surfaces is explained by a deterministic model that involves three key parameters: the drying time scale of the liquid film wicking into the surface structures (τd), the heating length scale of the liquid film (δH) and the area fraction of the evaporating liquid film (Ar). It is shown that the model accurately predicts the optimum spacing between surface structures (i.e. pillars fabricated on the microchannel wall) in boiling of two fluids FC-72 and water with fundamentally different wicking characteristics.

  15. Multiphysics modeling of two-phase film boiling within porous corrosion deposits

    Science.gov (United States)

    Jin, Miaomiao; Short, Michael

    2016-07-01

    Porous corrosion deposits on nuclear fuel cladding, known as CRUD, can cause multiple operational problems in light water reactors (LWRs). CRUD can cause accelerated corrosion of the fuel cladding, increase radiation fields and hence greater exposure risk to plant workers once activated, and induce a downward axial power shift causing an imbalance in core power distribution. In order to facilitate a better understanding of CRUD's effects, such as localized high cladding surface temperatures related to accelerated corrosion rates, we describe an improved, fully-coupled, multiphysics model to simulate heat transfer, chemical reactions and transport, and two-phase fluid flow within these deposits. Our new model features a reformed assumption of 2D, two-phase film boiling within the CRUD, correcting earlier models' assumptions of single-phase coolant flow with wick boiling under high heat fluxes. This model helps to better explain observed experimental values of the effective CRUD thermal conductivity. Finally, we propose a more complete set of boiling regimes, or a more detailed mechanism, to explain recent CRUD deposition experiments by suggesting the new concept of double dryout specifically in thick porous media with boiling chimneys.

  16. Mechanistic modeling of pool film-boiling and quench on a Candu calandria tube following a critical break LOCA

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, J.T.; Luxat, J.C. [McMaster University, A315 JHE Building, 1280 Main St.W. Hamilton, ON, L8S 4L7 (Canada)

    2008-07-01

    Following a postulated critical LBLOCA a pressure tube (PT) can experience creep deformation and balloon uniformly into contact with the calandria tube (CT). The resultant heat flux to CT is high as stored heat is transferred out of the hot PT. This heat flux can cause dryout on the outer surface of the CT and establish film boiling. This paper presents a model of buoyancy-driven natural convection film boiling on the outside of a horizontal tube with diameter relevant to a Candu CT (approximately 13 cm). A second order, non-linear and non-homogeneous ODE for vapour film thickness has been derived. The variation of steady state vapour film thickness prior to quench as a function of subcooling temperature, wall superheat, and incident heat flux is examined. The CT outer surface heatup rate and effective film boiling heat transfer coefficient from the model are in good agreement with available experimental data. (authors)

  17. Experimental study of the effect of the reduced graphene oxide films on nucleate boiling performances of inclined surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Hoon; Kong, Byeong Tak [Incheon National University, Incheon (Korea, Republic of); Kim, Ji Min [POSTECH, Pohang (Korea, Republic of); and others

    2016-05-15

    For the enhancing the CHF, surface coating techniques are available. Yang et al. performed small scale boiling experiments for the vessel lower head, which was coated by aluminum/copper micro particles. Recently, graphene has received much attention for applications in thermal engineering due to its large thermal conductivity. Ahn et al. used a silicon dioxide substrate, which was coated graphene films, as a heating surface during pool boiling experiments. The graphene films inhibited the formation of hot spots, increasing the CHF. For applying novel material 'Graphene' in nuclear industry, here we investigated the effects of graphene film coatings on boiling performances. The experimental pool boiling facility, copying the geometry of lower head of reactor, was designed for verifying orientation effects. The effects of graphene films coating on varied inclined heater surfaces were investigated. The CHF values were increased at every case, but the increased amounts were decreased for downward heater surfaces. At the downward-facing region, however, coating the RGO films would change the CHF mechanisms and boiling heat transfer performances. Generally, RGO films, made by colloidal fabrication, has defects on each flakes.

  18. Critical heat flux enhancement regarding to the thickness of graphene films under pool boiling

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Man; Park, Hyun Sun [Pohang Univ. of Science and Technology, Pohang (Korea, Republic of); Park, Youngjae; Kim, Hyungdae [Kyung Hee Univ., Yongin (Korea, Republic of); Kim, Dong Eok [Kyungpook Nat. Univ., Sangju (Korea, Republic of); Kim, Moo Hwan [Korea Inst. of Nuclear Safety, Daejeon (Korea, Republic of); Ahn, Ho Seon [Incheon Nat. Univ., Incheon (Korea, Republic of)

    2014-05-15

    The large thermal conductivity of the graphene films inhibits the formation of hot spots, thereby increasing the CHF. An infrared high-speed visualization showed graphene effect on boiling characteristics during operation. The graphene-coated heater showed an increase in BHT and CHF. As the thickness of the graphene films increased, the CHF also increased up to an asymptotic limit when the graphene layer was approximately 150 nm thick. The increased BHT was explained by the slight decrease in the wettability and the folded edges of the RGO flakes, which led to a decrease in the diameter of the departing bubbles, a larger bubble generation frequency, and an increase in the areal density of the bubble nucleation sites. The increase in the CHF was explained by considering the thermal activity of the graphene films, and the dependence thereof on the thickness and thermal properties of the layer, which was calculated based on high-speed IR visualization data.

  19. Evaluation of nonequilibrium effects in bundle dispersed-flow film boiling. [PWR; BWR

    Energy Technology Data Exchange (ETDEWEB)

    Morris, D.G.; Mullins, C.B.; Yoder, G.L.

    1983-01-01

    The effects of thermodynamic nonequilibrium in dispersed flow film boiling heat transfer are examined. Steady-state and transient rod-bundle data are used to evaluate several empirical heat-transfer models commonly employed to predict post-CHF behavior. The models that account for thermodynamic nonequilibrium perform adequately, while those that ignore nonequilibrium effects incur errors in wall superheat as high as 190/sup 0/K. Nonequilibrium effects can also be treated by explicitly modeling the phenomena. The thermal-hydraulic code COBRA-TF employs this approach. Using bundle data, the models in the code are evaluated. Analysis suggests that the interfacial heat transfer is overpredicted.

  20. Investigation on Minimum Film Boiling Point of Highly Heated Vertical Metal Rod in Aqueous Surfactant Solution

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chi Young; Kim, Jae Han [Pukyong Nat’l Univ., Busan (Korea, Republic of)

    2017-09-15

    In this study, experiments were conducted on the MFB(minimum film boiling) point of highly heated vertical metal rod quenched in aqueous surfactant solution at various temperature conditions. The aqueous Triton X-100 solution(100 wppm) and pure water were used as the liquid pool. Their temperatures ranged from 77 °C to 100 °C. A stainless steel vertical rod of initial center temperature of 500 °C was used as a test specimen. In both liquid pools, as the liquid temperature decreased, the time to reach the MFB point decreased with a parallel increase in the temperature and heat flux of the MFB point. However, over the whole present temperature range, in the aqueous Triton X-100 solution, the time to reach the MFB point was longer, while the temperature and heat flux of the MFB point were reduced when compared with pure water. Based on the present experimental data, this study proposed the empirical correlations to predict the MFB temperature of a high temperature vertical metal rod in pure water and in aqueous Triton X-100 solution.

  1. Atomistic modelling of evaporation and explosive boiling of thin film liquid argon over internally recessed nanostructured surface

    Energy Technology Data Exchange (ETDEWEB)

    Hasan, Mohammad Nasim, E-mail: nasim@me.buet.ac.bd.com; Shavik, Sheikh Mohammad, E-mail: shavik@me.buet.ac.bd.com; Rabbi, Kazi Fazle, E-mail: rabbi35.me10@gmail.com; Haque, Mominul, E-mail: mominulmarup@gmail.com [Department of Mechanical Engineering, Bangladesh University of Engineering & Technology (BUET) Dhaka-1000 (Bangladesh)

    2016-07-12

    Molecular dynamics (MD) simulations have been carried out to investigate evaporation and explosive boiling phenomena of thin film liquid argon on nanostructured solid surface with emphasis on the effect of solid-liquid interfacial wettability. The nanostructured surface considered herein consists of trapezoidal internal recesses of the solid platinum wall. The wetting conditions of the solid surface were assumed such that it covers both the hydrophilic and hydrophobic conditions and hence effect of interfacial wettability on resulting evaporation and boiling phenomena was the main focus of this study. The initial configuration of the simulation domain comprised of a three phase system (solid platinum, liquid argon and vapor argon) on which equilibrium molecular dynamics (EMD) was performed to reach equilibrium state at 90 K. After equilibrium of the three-phase system was established, the wall was set to different temperatures (130 K and 250 K for the case of evaporation and explosive boiling respectively) to perform non-equilibrium molecular dynamics (NEMD). The variation of temperature and density as well as the variation of system pressure with respect to time were closely monitored for each case. The heat flux normal to the solid surface was also calculated to illustrate the effectiveness of heat transfer for hydrophilic and hydrophobic surfaces in cases of both nanostructured surface and flat surface. The results obtained show that both the wetting condition of the surface and the presence of internal recesses have significant effect on normal evaporation and explosive boiling of the thin liquid film. The heat transfer from solid to liquid in cases of surface with recesses are higher compared to flat surface without recesses. Also the surface with higher wettability (hydrophilic) provides more favorable conditions for boiling than the low-wetting surface (hydrophobic) and therefore, liquid argon responds quickly and shifts from liquid to vapor phase faster in

  2. Iinvestigation by electrocontact method of interaction of water with hot surface in film and transition boiling regimes

    Science.gov (United States)

    Ivochkin, Y. P.; Kubrikov, K. G.; Sinkevich, O. A.; Zeigarnik, Y. A.

    2017-11-01

    Using the conductometric technique, the process of contact of subcooled distilled water with a hot surface was studied. The results of measurements of the parameters of the contact made in the range of the temperature change of the heated surface 170 ± 620 ° C are given. An experimental fact has been revealed, which indicates that a transition from film to bubble boiling is preceded by a short (several millisecond) hydrodynamic process that is characterized by intense interaction of waves at the vapour - liquid interface with the heated surface. With the help of wavelet analysis, the amplitude-frequency characteristics of this process are investigated and a qualitative physical model of its flow

  3. Aspects of subcooled boiling

    Energy Technology Data Exchange (ETDEWEB)

    Bankoff, S.G. [Northwestern Univ., Evanston, IL (United States)

    1997-12-31

    Subcooled boiling boiling refers to boiling from a solid surface where the bulk liquid temperature is below the saturation temperature (subcooled). Two classes are considered: (1) nucleate boiling, where, for large subcoolings, individual bubbles grow and collapse while remaining attached to the solid wall, and (2) film boiling, where a continuous vapor film separates the solid from the bulk liquid. One mechanism by which subcooled nucleate boiling results in very large surface heat transfer coefficient is thought to be latent heat transport within the bubble, resulting from simultaneous evaporation from a thin residual liquid layer at the bubble base, and condensation at the polar bubble cap. Another is the increased liquid microconvection around the oscillating bubble. Two related problems have been attacked. One is the rupture of a thin liquid film subject to attractive and repulsive dispersion forces, leading to the formation of mesoscopic drops, which then coalesce and evaporate. Another is the liquid motion in the vicinity of an oscillating contact line, where the bubble wall is idealized as a wedge of constant angle sliding on the solid wall. The subcooled film boiling problem has been attacked by deriving a general long-range nonlinear evolution equation for the local thickness of the vapor layer. Linear and weakly-nonlinear stability results have been obtained. A number of other related problems have been attacked.

  4. A low viscosity, low boiling point, clean solvent system for the rapid crystallisation of highly specular perovskite films

    Energy Technology Data Exchange (ETDEWEB)

    Noel, Nakita K.; Habisreutinger, Severin N.; Wenger, Bernard; Klug, Matthew T.; Hörantner, Maximilian T.; Johnston, Michael B.; Nicholas, Robin J.; Moore, David T.; Snaith, Henry J.

    2017-01-01

    Perovskite-based photovoltaics have, in recent years, become poised to revolutionise the solar industry. While there have been many approaches taken to the deposition of this material, one-step spin-coating remains the simplest and most widely used method in research laboratories. Although spin-coating is not recognised as the ideal manufacturing methodology, it represents a starting point from which more scalable deposition methods, such as slot-dye coating or ink-jet printing can be developed. Here, we introduce a new, low-boiling point, low viscosity solvent system that enables rapid, room temperature crystallisation of methylammonium lead triiodide perovskite films, without the use of strongly coordinating aprotic solvents. Through the use of this solvent, we produce dense, pinhole free films with uniform coverage, high specularity, and enhanced optoelectronic properties. We fabricate devices and achieve stabilised power conversion efficiencies of over 18% for films which have been annealed at 100 degrees C, and over 17% for films which have been dried under vacuum and have undergone no thermal processing. This deposition technique allows uniform coating on substrate areas of up to 125 cm2, showing tremendous promise for the fabrication of large area, high efficiency, solution processed devices, and represents a critical step towards industrial upscaling and large area printing of perovskite solar cells.

  5. The electroplated Pd-Co alloy film on 316 L stainless steel and the corrosion resistance in boiling acetic acid and formic acid mixture with stirring

    Science.gov (United States)

    Li, Sirui; Zuo, Yu; Tang, Yuming; Zhao, Xuhui

    2014-12-01

    Pd-Co alloy films were deposited on 316 L stainless steel by electroplating. Scanning electronic microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, weight loss test and polarization test were used to determine the properties of the Pd-Co alloy films. The Pd-Co films show fine grain size, low porosity and obviously high micro-hardness. The Co content in the film can be controlled in a large range from 21.9 at.% to 57.42 at.%. Pd is rich on the Pd-Co film surface, which is benefit to increase the corrosion resistance. In boiling 90% acetic acid plus 10% formic acid mixture with 0.005 M Br- under stirring, the Pd-Co plated stainless steel samples exhibit evidently better corrosion resistance in contrast to Pd plated samples. The good corrosion resistance of the Pd-Co alloy film is explained by the better compactness, the lower porosity, and the obviously higher micro-hardness of the alloy films, which increases the resistance to erosion and retards the development of micro-pores in the film.

  6. Transient boiling crisis of cryogenic liquids

    NARCIS (Netherlands)

    Deev, [No Value; Kharitonov, VS; Kutsenko, KV; Lavrukhin, AA

    2004-01-01

    This paper introduces a new physical model of boiling crisis under rapid increase of power on the heated surface. The calculation of the time interval of the transition to film boiling in cryogenic liquids was carried out depending on heat flux and pressure. The obtained results are in good

  7. Pool Boiling of Hydrocarbon Mixtures on Water

    Energy Technology Data Exchange (ETDEWEB)

    Boee, R.

    1996-09-01

    In maritime transport of liquefied natural gas (LNG) there is a risk of spilling cryogenic liquid onto water. The present doctoral thesis discusses transient boiling experiments in which liquid hydrocarbons were poured onto water and left to boil off. Composition changes during boiling are believed to be connected with the initiation of rapid phase transition in LNG spilled on water. 64 experimental runs were carried out, 14 using pure liquid methane, 36 using methane-ethane, and 14 using methane-propane binary mixtures of different composition. The water surface was open to the atmosphere and covered an area of 200 cm{sup 2} at 25 - 40{sup o}C. The heat flux was obtained by monitoring the change of mass vs time. The void fraction in the boiling layer was measured with a gamma densitometer, and a method for adapting this measurement concept to the case of a boiling cryogenic liquid mixture is suggested. Significant differences in the boil-off characteristics between pure methane and binary mixtures revealed by previous studies are confirmed. Pure methane is in film boiling, whereas the mixtures appear to enter the transitional boiling regime with only small amounts of the second component added. The results indicate that the common assumption that LNG will be in film boiling on water because of the high temperature difference, may be questioned. Comparison with previous work shows that at this small scale the results are influenced by the experimental apparatus and procedures. 66 refs., 76 figs., 28 tabs.

  8. Carbon nanotube-assisted electrodeposition. Part II: Superior pseudo-capacitive behavior of manganese oxide film electrodeposited at high current densities

    Science.gov (United States)

    Eftekhari, Ali; Molaei, Foroogh

    2015-01-01

    A practical approach for controlling the morphology and electrochemical properties of electroactive materials is proposed. In this study, manganese oxide films were galvanostatically deposited in the presence of a small amount of carbon nanotube (CNT). The resulting film cannot be considered as a CNT-based nanocomposite, as no CNT is detected by electron microscopy. However, the manganese oxide electrodeposited delivers an excellent pseudo-capacitive behavior to be used as a superior supercapacitor. The samples prepared by applying a current density of 3.0 mA cm-2 showed a specific capacitance of 280 F g-1. As it seems that the capacitance of this electrode is related to the chemisorption of the alkali cation, an extremely high specific capacitance of 434 F g-1 was achieved in a saturated medium of Li electrolyte. This high specific capacitance can be attributed to a bulk process. The presence of carbon nanotubes results in the formation of nanostructured films which provide a better accessibility for capacitive behavior. Although the exact mechanism for this phenomenon is still vague, the presence of carbon nanotubes (probably as a solid charge carrier) close to the electrode surface is apparently responsible for a different pathway for the electrodeposition process.

  9. Boiling Heat Transfer to Halogenated Hydrocarbon Refrigerants

    Science.gov (United States)

    Yoshida, Suguru; Fujita, Yasunobu

    The current state of knowledge on heat transfer to boiling refrigerants (halogenated hydrocarbons) in a pool and flowing inside a horizontal tube is reviewed with an emphasis on information relevant to the design of refrigerant evaporators, and some recommendations are made for future research. The review covers two-phase flow pattern, heat transfer characteristics, correlation of heat transfer coefficient, influence of oil, heat transfer augmentation, boiling from tube-bundle, influence of return bend, burnout heat flux, film boiling, dryout and post-dryout heat transfer.

  10. Comment on "Tunable Design of Structural Colors Produced by Pseudo-1D Photonic Crystals of Graphene Oxide" and Thin-Film Interference from Dried Graphene Oxide Film.

    Science.gov (United States)

    Hong, Seung-Ho; Song, Jang-Kun

    2017-04-01

    The mechanism of the iridescent color reflection from dried thin graphene oxide (GO) film on Si wafer is clarified. Dissimilarly to the photonic crystalline reflection in aqueous GO dispersion, the color reflection in dried GO film originates from the thin film interference. The peak reflection can reach 23% by optimizing the GO thickness and the substrate. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Numerical simulation of pool boiling of a Lennard-Jones liquid

    KAUST Repository

    Inaoka, Hajime

    2013-09-01

    We performed a numerical simulation of pool boiling by a molecular dynamics model. In the simulation, a liquid composed of Lennard-Jones particles in a uniform gravitational field is heated by a heat source at the bottom of the system. The model successfully reproduces the change in regimes of boiling from nucleate boiling to film boiling with the increase of the heat source temperature. We present the pool boiling curve by the model, whose general behavior is consistent with those observed in experiments of pool boiling. © 2013 Elsevier B.V. All rights reserved.

  12. Odd-Boiled Eggs

    Science.gov (United States)

    Kaminsky, Kenneth; Scheman, Naomi

    2010-01-01

    At a Shabbat lunch in Madrid not long ago, the conversation turned to the question of boiling eggs. One of the guests mentioned that a Dutch rabbi he knew had heard that in order to make it more likely that boiled eggs be kosher, you should add an egg to the pot if the number you began with was even. According to the laws of Kashruth, Jews may not…

  13. Nucleate boiling heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Saiz Jabardo, J.M. [Universidade da Coruna (Spain). Escola Politecnica Superior], e-mail: mjabardo@cdf.udc.es

    2009-07-01

    Nucleate boiling heat transfer has been intensely studied during the last 70 years. However boiling remains a science to be understood and equated. In other words, using the definition given by Boulding, it is an 'insecure science'. It would be pretentious of the part of the author to explore all the nuances that the title of the paper suggests in a single conference paper. Instead the paper will focus on one interesting aspect such as the effect of the surface microstructure on nucleate boiling heat transfer. A summary of a chronological literature survey is done followed by an analysis of the results of an experimental investigation of boiling on tubes of different materials and surface roughness. The effect of the surface roughness is performed through data from the boiling of refrigerants R-134a and R-123, medium and low pressure refrigerants, respectively. In order to investigate the extent to which the surface roughness affects boiling heat transfer, very rough surfaces (4.6 {mu}m and 10.5 {mu}m ) have been tested. Though most of the data confirm previous literature trends, the very rough surfaces present a peculiar behaviour with respect to that of the smoother surfaces (Ra<3.0 {mu}m). (author)

  14. Studies on micro-structures at vapor-liquid interfaces of film boiling on hot liquid surface at arriving of a shock pressure

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Akira; Lee, S. [Tokyo Inst. of Tech. (Japan)

    1998-01-01

    In vapor explosions, a pressure wave (shock wave) plays a fundamental role in the generation, propagation and escalation of the explosion. Transient volume change by rapid heat flow from a high temperature liquid to a low temperature volatile one and phase change generate micro-scale flow and the pressure wave. One of key issues for the vapor explosion is to make clear the mechanism to support the explosive energy release from hot drop to cold liquid. According to our observations by an Image Converter Camera, growth rate of vapor film around a hot tin drop became several times higher than that around a hot Platinum tube at the same conditions when a pressure pulse collapsed the film. The thermally induced fragmentation was followed by the explosive growth rate of the hot drop. In the previous report, we have proposed that the interface instability and fragmentation model in which the fine Taylor instability of vapor-liquid interface at the collapsing and re-growth phase of vapor film and the instability induced by the high pressure spots at the drop surface were assumed. In this study, the behavior of the vapor-liquid interface region at arrival of a pressure pulse was investigated by the CIPRIS code which is able to simulate dynamics of transient multi-phase interface regions. It is compared with the observation results. Through detailed investigations of these results, the mechanisms of the thermal fragmentation of single drop are discussed. (J.P.N.)

  15. A Fundamental Study of Nucleate Pool Boiling Under Microgravity

    Science.gov (United States)

    Ervin, Jamie S.; Merte, Herman, Jr.

    1996-01-01

    An experimental study of incipient boiling in short-term microgravity and with a/g = +/- 1 for pool boiling was performed. Calibrated thin gold films sputtered on a smoothly polished quartz surface were used simultaneously for thermal-resistance measurements and heating of the boiling surface. The gold films were used for both transient and quasi-steady heating surface temperature measurements. Two test vessels were constructed for precise measurement and control of fluid temperature and pressure: a laboratory pool boiling vessel for the a/g = +/- 1 experiments and a pool boiling vessel designed for the 131 m free-fall in the NASA Lewis Research Center Microgravity Research Facility for the microgravity tests. Measurements included the heater surface temperature, the pressure near the heating surface, the bulk liquid temperatures. High speed photography (up to 1,000 frames per second) was used in the experiments. With high quality microgravity and the measured initial temperature of the quiescent test fluid, R113, the temperature distribution in the liquid at the moment of boiling inception resulting from an imposed step in heat flux is known with a certainty not possible previously. The types of boiling propagation across the large flat heating surface, some observed here for the first time, are categorized; the conditions necessary for their occurrence are described. Explosive boiling propagation with a striking pattern of small scale protuberances over the entire vapor mass periphery not observed previously at low heat flux levels (on the order of 5 W/cm(exp 2)) is described. For the heater surface with a/g = -1, a step in the heater surface temperature of short duration was imposed. The resulting liquid temperature distribution at the moment of boiling inception was different from that obtained with a step in heat flux.

  16. CHF Phenomena by Photographic Study of Boiling Behavior due to Transient Heat Inputs

    Directory of Open Access Journals (Sweden)

    Jongdoc Park

    2012-01-01

    Full Text Available The transient boiling heat transfer characteristics in a pool of water and highly wetting liquids such as ethanol and FC-72 due to an exponentially increasing heat input of various rates were investigated using the 1.0 mm diameter experimental heater shaped in a horizontal cylinder for wide ranges of pressure and subcooling. The trend of critical heat flux (CHF values in relation to the periods was divided into three groups. The CHF belonging to the 1st group with a longer period occurs with a fully developed nucleate boiling (FDNB heat transfer process. For the 2nd group with shorter periods, the direct transition to film boiling from non boiling occurs as an explosive boiling. The direct boiling transition at the CHF from non-boiling regime to film boiling occurred without a heat flux increase. It was confirmed that the initial boiling behavior is significantly affected by the property and the wettability of the liquid. The photographic observations on the vapor bubble behavior during transitions to film boiling were performed using a high-speed video camera system.

  17. CFD analysis of flow boiling in the ITER first wall

    Energy Technology Data Exchange (ETDEWEB)

    Domalapally, Phani, E-mail: phani.domalapally@polito.it [Dipartimento di Energetica, Politecnico, I-10129 Torino (Italy); Rizzo, Enrico [Institut fuer Technische Physik, Karlsruhe Institute of Technology, Karlsruhe (Germany); Savoldi Richard, Laura; Subba, Fabio; Zanino, Roberto [Dipartimento di Energetica, Politecnico, I-10129 Torino (Italy)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer Two boiling models, Rohsenow model for nucleate boiling, switching to the Volume of Fluid for film boiling using STAR-CCM+ and Bergles-Rohsenow model, for which we developed a User Defined Function, implemented in FLUENT, are tested and compared on a flat-channel geometry. Black-Right-Pointing-Pointer Performance is checked in terms of accuracy and computational cost. Black-Right-Pointing-Pointer As a first approximation analysis Bergles-Rohsenow model may be a good choice, if more accurate information on thermal behavior or flow field is required, the other should be preferred. - Abstract: This paper compares two Computational Fluid Dynamic (CFD) approaches for the analysis of flow boiling inside the first wall (FW) of the International Thermonuclear Experimental Reactor (ITER): (1) the Rohsenow model for nucleate boiling, seamlessly switching to the Volume of Fluid (VOF) approach for film boiling, as available in the commercial CFD code STAR-CCM+, (2) the Bergles-Rohsenow (BR) model, for which we developed a User Defined Function (UDF), implemented in the commercial code FLUENT. The physics of both models is described, and the results with different inlet conditions and heating levels are compared with experimental results obtained at the Efremov Institute, Russia. The performance of both models is compared in terms of accuracy and computational cost.

  18. Free convection film flows and heat transfer laminar free convection of phase flows and models for heat-transfer analysis

    CERN Document Server

    Shang, De-Yi

    2012-01-01

    This book presents recent developments in our systematic studies of hydrodynamics and heat and mass transfer in laminar free convection, accelerating film boiling and condensation of Newtonian fluids, as well as accelerating film flow of non-Newtonian power-law fluids (FFNF). These new developments provided in this book are (i) novel system of analysis models based on the developed New Similarity Analysis Method; (ii) a system of advanced methods for treatment of gas temperature- dependent physical properties, and liquid temperature- dependent physical properties; (iii) the organically combined models of the governing mathematical models with those on treatment model of variable physical properties; (iv) rigorous approach of overcoming a challenge on accurate solution of three-point boundary value problem related to two-phase film boiling and condensation; and (v) A pseudo-similarity method of dealing with thermal boundary layer of FFNF for greatly simplifies the heat-transfer analysis and numerical calculati...

  19. Discrete pseudo-integrals

    Czech Academy of Sciences Publication Activity Database

    Mesiar, Radko; Li, J.; Pap, E.

    2013-01-01

    Roč. 54, č. 3 (2013), s. 357-364 ISSN 0888-613X R&D Projects: GA ČR GAP402/11/0378 Institutional support: RVO:67985556 Keywords : concave integral * pseudo-addition * pseudo- multiplication Subject RIV: BA - General Mathematics Impact factor: 1.977, year: 2013 http://library.utia.cas.cz/separaty/2013/E/mesiar-discrete pseudo-integrals. pdf

  20. Unique negative permittivity of the pseudo conducting radial zinc oxide-poly(vinylidene fluoride) nanocomposite film: Enhanced dielectric and electromagnetic interference shielding properties

    Energy Technology Data Exchange (ETDEWEB)

    Aepuru, Radhamanohar [Department of Materials Engineering, Defence Institute of Advanced Technology, Girinagar, Pune 411025 (India); Bhaskara Rao, B.V.; Kale, S.N. [Department of Applied Physics, Defence Institute of Advanced Technology, Pune 411025 (India); Panda, H.S., E-mail: himanshusp@diat.ac.in [Department of Materials Engineering, Defence Institute of Advanced Technology, Girinagar, Pune 411025 (India)

    2015-11-01

    Flower like radial zinc oxide (RZnO) was prepared by using a facile solvothermal method and used to prepare poly(vinylidene fluoride) (PVDF) based nanocomposites. Structural informations of the samples are analyzed by X-ray diffraction and correlated with high resolution transmission electron microscopy along with high annular angular dark field scanning transmission electron microscopy (HAADF-STEM). For the first time, stability studies are carried out by solvent relaxation nuclear magnetic resonance experiments. Dielectric studies of the PVDF and PVDF-RZnO nanocomposites are reported over the wide range of frequency (0.01 Hz–1 MHz) and temperature (25–90 °C). Dielectric property of the PVDF-RZnO nanocomposites was significantly improved wrt filler percentage in PVDF. Unique negative permittivity was observed in the composites having higher filler content (>40 wt%) typically at low frequencies. First time, it is observed that the higher RZnO content in PVDF results the formation of pseudo conducting network and hence improved the electromagnetic shielding efficiency (85%) than PVDF and PVDF-commercial ZnO composites. - Highlights: • Radial ZnO-PVDF nanocomposites were fabricated by using solution casting. • Pseudo conducting network is confirmed through cryo-fracture morphology study. • Stability study of the nano fillers was performed in the polymer matrix. • Unique negative permittivity behavior of the nanocomposites was observed. • EMI shielding property of the radial ZnO-PVDF nanocomposites was performed.

  1. Boiling liquid cauldron status report

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, M.A.

    1980-12-28

    The progress made over the past year in assessing the feasibility of the high-temperature, boiling cauldron blanket concept for the tanden mirror reactor is reviewed. The status of the proposed experiments and recently revised estimates of the vapor void fraction in the boiling pool are discussed.

  2. HORIZONTAL BOILING REACTOR SYSTEM

    Science.gov (United States)

    Treshow, M.

    1958-11-18

    Reactors of the boiling water type are described wherein water serves both as the moderator and coolant. The reactor system consists essentially of a horizontal pressure vessel divided into two compartments by a weir, a thermal neutronic reactor core having vertical coolant passages and designed to use water as a moderator-coolant posltioned in one compartment, means for removing live steam from the other compartment and means for conveying feed-water and water from the steam compartment to the reactor compartment. The system further includes auxiliary apparatus to utilize the steam for driving a turbine and returning the condensate to the feed-water inlet of the reactor. The entire system is designed so that the reactor is self-regulating and has self-limiting power and self-limiting pressure features.

  3. Pseudo Class III malocclusion

    National Research Council Canada - National Science Library

    Al-Hummayani, Fadia M

    2016-01-01

    .... This case report represents a none traditional treatment modality to treat deep anterior crossbite in an adult pseudo class III malocclusion complicated by severely retruded, supraerupted upper and lower incisors...

  4. Boiling process in oil coolers on porous elements

    Directory of Open Access Journals (Sweden)

    Genbach Alexander A.

    2016-01-01

    Full Text Available Holography and high-speed filming were used to reveal movements and deformations of the capillary and porous material, allowing to calculate thermo-hydraulic characteristics of boiling liquid in the porous structures. These porous structures work at the joint action of capillary and mass forces, which are generalised in the form of dependences used in the calculation for oil coolers in thermal power plants (TPP. Furthermore, the mechanism of the boiling process in porous structures in the field of mass forces is explained. The development process of water steam formation in the mesh porous structures working at joint action of gravitational and capillary forces is investigated. Certain regularities pertained to the internal characteristics of boiling in cells of porous structure are revealed, by means of a holographic interferometry and high-speed filming. Formulas for calculation of specific thermal streams through thermo-hydraulic characteristics of water steam formation in mesh structures are obtained, in relation to heat engineering of thermal power plants. This is the first calculation of heat flow through the thermal-hydraulic characteristics of the boiling process in a reticulated porous structure obtained by a photo film and holographic observations.

  5. Enhanced heat transfer in confined pool boiling

    NARCIS (Netherlands)

    Rops, C.M.; Lindken, R.; Velthuis, J.F.M.; Westerweel, J.

    2009-01-01

    We report the results of an experimental investigation of the heat transfer during nucleate boiling on a spatially confined boiling surface. The heat flux as a function of the boiling surface temperature was measured in pool boiling pots with diameters ranging from 15 mm down to 4.5 mm. It was found

  6. Boiling crisis and non-equilibrium drying transition

    CERN Document Server

    Nikolayev, Vadim

    2016-01-01

    Boiling crisis is the rapid formation of the quasi-continuous vapor film between the heater and the liquid when the heat supply exceeds a critical value. We propose a mechanism for the boiling crisis that is based on the spreading of the dry spot under a vapor bubble. The spreading is initiated by the vapor recoil force, a force coming from the liquid evaporation into the bubble. Since the evaporation intensity increases sharply near the triple contact line, the influence of the vapor recoil can be described as a change of the apparent contact angle. Therefore, for the most usual case of complete wetting of the heating surface by the liquid, the boiling crisis can be understood as a drying transition from complete to partial wetting. The state of nucleate boiling, which is boiling in its usual sense, is characterized by a very large rate of heat transfer from the heating surface to the bulk because the superheated liquid is carried away from the heating surface by the departing vapor bubbles. If the heating p...

  7. Development boiling to sprinkled tube bundle

    Directory of Open Access Journals (Sweden)

    Kracík Petr

    2016-01-01

    Full Text Available This paper presents results of a studied heat transfer coefficient at the surface of a sprinkled tube bundle where boiling occurs. Research in the area of sprinkled exchangers can be divided into two major parts. The first part is research on heat transfer and determination of the heat transfer coefficient at sprinkled tube bundles for various liquids, whether boiling or not. The second part is testing of sprinkle modes for various tube diameters, tube pitches and tube materials and determination of individual modes’ interface. All results published so far for water as the falling film liquid apply to one to three tubes for which the mentioned relations studied are determined in rigid laboratory conditions defined strictly in advance. The sprinkled tubes were not viewed from the operational perspective where there are more tubes and various modes may occur in different parts with various heat transfer values. The article focuses on these processes. The tube is located in a low-pressure chamber where vacuum is generated using an exhauster via ejector. The tube consists of smooth copper tubes of 12 mm diameter placed horizontally one above another.

  8. Flow boiling in expanding microchannels

    CERN Document Server

    Alam, Tamanna

    2017-01-01

    This Brief presents an up to date summary of details of the flow boiling heat transfer, pressure drop and instability characteristics; two phase flow patterns of expanding microchannels. Results obtained from the different expanding microscale geometries are presented for comparison and addition to that, comparison with literatures is also performed. Finally, parametric studies are performed and presented in the brief. The findings from this study could help in understanding the complex microscale flow boiling behavior and aid in the design and implementation of reliable compact heat sinks for practical applications.

  9. LMFBR safety and sodium boiling

    Energy Technology Data Exchange (ETDEWEB)

    Hinkle, W.D.; Tschamper, P.M.; Fontana, M.H.; Henry, R.E.; Padilla, A. Jr.

    1978-01-01

    Within the U.S. Fast Breeder Reactor Safety R and D Work Breakdown Structure for Line of Assurance 2, Limit Core Damage, the influence of sodium boiling upon the progression and termination of accidents is being studied in loss of flow, transient overpower, loss of piping integrity, loss of shutdown heat removal system and local fault situations. The pertinent analytical and experimental results of this research to date are surveyed and compared with the requirements for demonstrating the effectiveness of this line of assurance. A discussion of specific technical issues concerned with sodium boiling and the need for future development work is also presented.

  10. A high-fidelity approach towards simulation of pool boiling

    Science.gov (United States)

    Yazdani, Miad; Radcliff, Thomas; Soteriou, Marios; Alahyari, Abbas A.

    2016-01-01

    A novel numerical approach is developed to simulate the multiscale problem of pool-boiling phase change. The particular focus is to develop a simulation technique that is capable of predicting the heat transfer and hydrodynamic characteristics of nucleate boiling and the transition to critical heat flux on surfaces of arbitrary shape and roughness distribution addressing a critical need to design enhanced boiling heat transfer surfaces. The macro-scale of the phase change and bubble dynamics is addressed through employing off-the-shelf Computational Fluid Dynamics (CFD) methods for interface tracking and interphase mass and energy transfer. The micro-scale of the microlayer, which forms at early stage of bubble nucleation near the wall, is resolved through asymptotic approximation of the thin-film theory which provides a closed-form solution for the distribution of the micro-layer and its influence on the evaporation process. In addition, the sub-grid surface roughness is represented stochastically through probabilistic density functions and its role in bubble nucleation and growth is then represented based on the thermodynamics of nucleation process. This combination of deterministic CFD, local approximation, and stochastic representation allows the simulation of pool boiling on any surface with known roughness and enhancement characteristics. The numerical model is validated for dynamics and hydrothermal characteristics of a single nucleated bubble on a flat surface against available literature data. In addition, the prediction of pool-boiling heat transfer coefficient is verified against experimental measurements as well as reputable correlations for various roughness distributions and different surface orientations. Finally, the model is employed to demonstrate pool-boiling phenomenon on enhanced structures with reentrance cavities and to explore the effect of enhancement feature design on thermal and hydrodynamic characteristics of these surfaces.

  11. Boiling flow through diverging microchannel

    Indian Academy of Sciences (India)

    J. Heat Transfer ASME 1301–1310. Lee P C and Pan C 2008 Boiling heat transfer and two-phase flow of water in a single shallow microchannel with a uniform or diverging cross section. J. Micromechanics and Microengineering 13: 18. Lee P C, Tseng F G and Pan C 2004 Bubble dynamics in microchannels: Part I. Single ...

  12. Quantum Pseudo-Telepathy

    Science.gov (United States)

    Brassard, Gilles; Broadbent, Anne; Tapp, Alain

    2005-11-01

    Quantum information processing is at the crossroads of physics, mathematics and computer science. It is concerned with that we can and cannot do with quantum information that goes beyond the abilities of classical information processing devices. Communication complexity is an area of classical computer science that aims at quantifying the amount of communication necessary to solve distributed computational problems. Quantum communication complexity uses quantum mechanics to reduce the amount of communication that would be classically required. Pseudo-telepathy is a surprising application of quantum information processing to communication complexity. Thanks to entanglement, perhaps the most nonclassical manifestation of quantum mechanics, two or more quantum players can accomplish a distributed task with no need for communication whatsoever, which would be an impossible feat for classical players. After a detailed overview of the principle and purpose of pseudo-telepathy, we present a survey of recent and no-so-recent work on the subject. In particular, we describe and analyse all the pseudo-telepathy games currently known to the authors.

  13. Experimental Study on Boiling Crisis in Pool Boiling

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Satbyoul; Kim, Hyungdae [Kyung Hee University, Yongin (Korea, Republic of)

    2016-10-15

    They postulated that failure in re-wetting of a dry patch by a cooling liquid is governed by microhydrodynamics near the wall. Chu et al. commonly observed that active coalescence of newly generated bubbles with preexisting bubbles results in a residual dry patch and prevents the complete rewetting of the dry patch, leading to CHF. In this work, to reveal the key physical mechanism of CHF during the rewetting process of a dry patch, dynamics of dry patches and thermal pattern of a boiling surface are simultaneously observed using TR and IR thermometry techniques. Local dynamics of dry patch and thermal pattern on a boiling surface in synchronized manner for both space and time using TR and IR thermometry were measured during pool boiling of water. Observation and quantitative examination of CHF was performed. - The hydrodynamic and thermal behaviors of irreversible dry patch were observed. The dry patches coalesce into a large dry patch and it locally dried out. Due to the failure of liquid rewetting, the dry patch is not completely rewetted, resulting in the burn out at which temperature is -140°C. - When temperature of a dry patch rises beyond the instantaneous nucleation temperature, several bubbles nucleate at the head of the advancing liquid meniscus and prevents the liquid front, and eventually the overheated dry patch remains alive after the departure of the massive bubble.

  14. PSEUDO-CODEWORD LANDSCAPE

    Energy Technology Data Exchange (ETDEWEB)

    CHERTKOV, MICHAEL [Los Alamos National Laboratory; STEPANOV, MIKHAIL [Los Alamos National Laboratory

    2007-01-10

    The authors discuss performance of Low-Density-Parity-Check (LDPC) codes decoded by Linear Programming (LP) decoding at moderate and large Signal-to-Noise-Ratios (SNR). Frame-Error-Rate (FER) dependence on SNR and the noise space landscape of the coding/decoding scheme are analyzed by a combination of the previously introduced instanton/pseudo-codeword-search method and a new 'dendro' trick. To reduce complexity of the LP decoding for a code with high-degree checks, {ge} 5, they introduce its dendro-LDPC counterpart, that is the code performing identifically to the original one under Maximum-A-Posteriori (MAP) decoding but having reduced (down to three) check connectivity degree. Analyzing number of popular LDPC codes and their dendro versions performing over the Additive-White-Gaussian-Noise (AWGN) channel, they observed two qualitatively different regimes: (i) error-floor sets early, at relatively low SNR, and (ii) FER decays with SNR increase faster at moderate SNR than at the largest SNR. They explain these regimes in terms of the pseudo-codeword spectra of the codes.

  15. Bubble spreading during the boiling crisis: modelling and experimenting in microgravity

    CERN Document Server

    Nikolayev, Vadim; Garrabos, Y; Lecoutre, C; Chatain, D

    2016-01-01

    Boiling is a very efficient way to transfer heat from a heater to the liquid carrier. We discuss the boiling crisis, a transition between two regimes of boiling: nucleate and film boiling. The boiling crisis results in a sharp decrease in the heat transfer rate, which can cause a major accident in industrial heat exchangers. In this communication, we present a physical model of the boiling crisis based on the vapor recoil effect. Under the action of the vapor recoil the gas bubbles begin to spread over the heater thus forming a germ for the vapor film. The vapor recoil force not only causes its spreading, it also creates a strong adhesion to the heater that prevents the bubble departure, thus favoring the further spreading. Near the liquid-gas critical point, the bubble growth is very slow and allows the kinetics of the bubble spreading to be observed. Since the surface tension is very small in this regime, only microgravity conditions can preserve a convex bubble shape. In the experiments both in the Mir spa...

  16. Criticality in the slowed-down boiling crisis at zero gravity.

    Science.gov (United States)

    Charignon, T; Lloveras, P; Chatain, D; Truskinovsky, L; Vives, E; Beysens, D; Nikolayev, V S

    2015-05-01

    Boiling crisis is a transition between nucleate and film boiling. It occurs at a threshold value of the heat flux from the heater called CHF (critical heat flux). Usually, boiling crisis studies are hindered by the high CHF and short transition duration (below 1 ms). Here we report on experiments in hydrogen near its liquid-vapor critical point, in which the CHF is low and the dynamics slow enough to be resolved. As under such conditions the surface tension is very small, the experiments are carried out in the reduced gravity to preserve the conventional bubble geometry. Weightlessness is created artificially in two-phase hydrogen by compensating gravity with magnetic forces. We were able to reveal the fractal structure of the contour of the percolating cluster of the dry areas at the heater that precedes the boiling crisis. We provide a direct statistical analysis of dry spot areas that confirms the boiling crisis at zero gravity as a scale-free phenomenon. It was observed that, in agreement with theoretical predictions, saturated boiling CHF tends to zero (within the precision of our thermal control system) in zero gravity, which suggests that the boiling crisis may be observed at any heat flux provided the experiment lasts long enough.

  17. Boils

    Science.gov (United States)

    ... infection: Antibacterial soaps Antiseptic (germ-killing) washes Keeping clean (such as thorough hand washing) Alternative Names Furuncle Images Hair follicle anatomy References Habif TP. Bacterial infections. In: ...

  18. A molecular dynamics study of phobic/philic nano-patterning on pool boiling heat transfer

    Science.gov (United States)

    Diaz, Ricardo; Guo, Zhixiong

    2017-03-01

    Molecular dynamics (MD) simulations were employed to investigate the pool boiling heat transfer of a liquid argon thin film on a flat, horizontal copper wall structured with vertical nanoscale pillars. The efficacy of phobic/philic nano-patterning for enhancing boiling heat transfer was scrutinized. Both nucleate and explosive boiling modes were considered. An error analysis demonstrated that the typical 2.5σ cutoff in MD simulations could under-predict heat flux by about 8.7 %, and 6σ cutoff was chosen here in order to maintain high accuracy. A new coordination number criterion was also introduced to better quantify evaporation characteristics. Results indicate that the argon-phobic/philic patterning tends to either have no effect, or decrease overall boiling heat flux, while the argon-philic nano-pillar/argon-philic wall shows the best heat transfer performance.

  19. CHIMNEY FOR BOILING WATER REACTOR

    Science.gov (United States)

    Petrick, M.

    1961-08-01

    A boiling-water reactor is described which has vertical fuel-containing channels for forming steam from water. Risers above the channels increase the head of water radially outward, whereby water is moved upward through the channels with greater force. The risers are concentric and the radial width of the space between them is somewhat small. There is a relatively low rate of flow of water up through the radially outer fuel-containing channels, with which the space between the risers is in communication. (AE C)

  20. Gamma heated subassembly for sodium boiling experiments

    Energy Technology Data Exchange (ETDEWEB)

    Artus, S.C.

    1975-01-01

    The design of a system to boil sodium in an LMFBR is examined. This design should be regarded as a first step in a series of boiling experiments. The reactor chosen for the design of the boiling apparatus is the Experimental Breeder Reactor-II (EBR-II), located at the National Reactor Testing Station in Idaho. Criteria broadly classified as design objectives and design requirements are discussed.

  1. Instability in flow boiling in microchannels

    CERN Document Server

    Saha, Sujoy Kumar

    2016-01-01

    This Brief addresses the phenomena of instability in flow boiling in microchannels occurring in high heat flux electronic cooling. A companion edition in the SpringerBrief Subseries on Thermal Engineering and Applied Science to “Critical Heat Flux in Flow Boiling in Microchannels,” and "Heat Transfer and Pressure Drop in Flow Boiling in Microchannels,"by the same author team, this volume is idea for professionals, researchers, and graduate students concerned with electronic cooling.

  2. Sputtered Thin Film Research

    Science.gov (United States)

    1976-02-01

    influences substrate heating and uniformity of the deposition Th. ing .50 L/sec in the milxitorr range. Use of the turbomolecular pump in place...evaluation of the films eposited. Prior to film deposition the wafers were degreased, boiled in nitric acid rinsed in high resitivity deionized...the shutters were opened and film depositxon was initiated. After film deposition, heat treatments in nitrogen, hydrogen and oxygen were investigated

  3. Researching of the reduction of shock waves intensivity in the “pseudo boiling” layer

    Science.gov (United States)

    Pavlov, G. I.; Telyashov, D. A.; Kochergin, A. V.; Nakoryakov, P. V.; Sukhovaya, E. A.

    2017-09-01

    This article applies to the field of acoustics and deals with noise reduction of pulsating combustion chambers, in particular the reduction of the shock waves’ intensity with the help of pseudo boiling layer. In the course of work on a test stand that included a pulsator, a compressor with the receiver and a high pressure fan was simulated gas jet flowing from the chamber pulsating combustion and studied the effect of different types of fluidization on effect of reducing the sound pressure levels. Were obtained the experimental dependence of the sound pressure levels from parameters such as: height of the layer of granules; diameter of the used granules; amplitude of the pressure pulsations in the gas stream at the entrance to the camera; frequency of pressure pulsations. Based on the results of the study, it was concluded that the using of a pseudo boiling layer is promising for reducing shock wave noise.

  4. Parametric investigation on transient boiling heat transfer of metal rod cooled rapidly in water pool

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chi Young [Department of Fire Protection Engineering, Pukyong National University, 45, Yongso-ro, Nam-gu, Busan 48513 (Korea, Republic of); Kim, Sunwoo, E-mail: swkim@alaska.edu [Mechanical Engineering Department, University of Alaska Fairbanks, P. O. Box 755905, Fairbanks, AK 99775-5905 (United States)

    2017-03-15

    Highlights: • Effects of liquid subcooling, surface coating, material property, and surface oxidation are examined. • Liquid subcooling affects remarkably the quenching phenomena. • Cr-coated surfaces for ATF might extend the quenching duration. • Solids with low heat capacity shorten the quenching duration. • Surface oxidation can affect strongly the film boiling heat transfer and MFB point. - Abstract: In this work, the effects of liquid subcooling, surface coating, material property, and surface oxidation on transient pool boiling heat transfer were investigated experimentally using the vertical metal rod and quenching method. The change in rod temperature was measured with time during quenching, and the visualization of boiling around the test specimen was performed using the high-speed video camera. As the test materials, the zircaloy (Zry), stainless steel (SS), niobium (Nb), and copper (Cu) were tested. In addition, the chromium-coated niobium (Cr-Nb) and chromium-coated stainless steel (Cr-SS) were prepared for accident tolerant fuel (ATF) application. Low liquid subcooling and Cr-coating shifted the quenching curve to the right, which indicates a prolongation of quenching duration. On the other hand, the material with small heat capacity and surface oxidation caused the quenching curve to move to the left. To examine the influence of the material property and surface oxidation on the film boiling heat transfer performance and minimum film boiling (MFB) point in more detail, the wall temperature and heat flux were calculated from the present transient temperature profile using the inverse heat transfer analysis, and then the curves of wall temperature and heat flux in the film boiling regime were obtained. In the present experimental conditions, the effect of material property on the film boiling heat transfer performance and MFB point seemed to be minor. On the other hand, based on the experimental results of the Cu test specimen, the surface

  5. Boiling turbulent Rayleigh-Bénard convection

    NARCIS (Netherlands)

    Lakkaraju, R.

    2013-01-01

    A fundamental understanding of liquid-vapor phase transitions, mainly boiling phenomenon, is essential due to its omnipresence in science and technology. In industries, many empirical correlations exist on the heat transport to get an optimized and efficient thermal design of the boiling equipment.

  6. Pool boiling inversion through bubble induced macroconvection

    Science.gov (United States)

    Jaikumar, A.; Kandlikar, S. G.

    2017-02-01

    While numerous surface geometries have been explored to achieve enhancements in pool boiling critical heat flux and heat transfer coefficient (HTC), their mechanistic contributions towards the characteristics of the pool boiling curve are not clear. Recently reported pool boiling curves in literature have shown a trend where an increase in heat flux leads to a decrease in wall superheat. Consequently, a negative slope in the pool boiling curve accompanied by a sharp increase in HTC, termed here as boiling inversion, is observed. We demonstrate that this inversion is due to vapor stream induced reinforcement of an impinging liquid jet over the non-boiling regions. This behavior is characteristic of surfaces developed using separate liquid-vapor pathways and macroconvection enhancement mechanism resulting in a highly efficient self-sustained boiling configuration. The increased jet impingement velocities lead to higher HTCs with lower wall superheats. The analytical models available in literature are employed to quantitatively explain this trend. Furthermore, a self-adjusting boiling mechanism is seen at play wherein a reduction in nucleation activity due to lowering of wall superheat counters the increase in HTC induced by the macroconvective currents.

  7. Microlayer formation characteristics in pool isolated bubble boiling of water

    Science.gov (United States)

    Yabuki, Tomohide; Nakabeppu, Osamu

    2017-05-01

    Investigation of microlayer formation characteristics is important for developing a reliable nucleate boiling heat transfer model based on accurate physical mechanisms. Although formation mechanisms of the thin liquid film in two-phase flow of confined spaces, such as micro-tubes and closely positioned parallel plates, have been thoroughly studied, microlayer formation mechanisms of pool boiling have been sparsely studied. In a previous study (Yabuki and Nakabeppu in Int J Heat Mass Transf 76:286-297, 2014; Int J Heat Mass Transf 100:851-860, 2016), the spatial distribution of initial microlayer thickness under pool boiling bubbles was calculated by transient heat conduction analysis using the local wall temperature measured with a MEMS sensor. In this study, the hydrodynamic characteristics of microlayer formation in pool boiling were investigated using the relationship between derived initial microlayer thickness and microlayer formation velocity determined by transient local heat flux data. The trend of microlayer thickness was found to change depending on the thickness of the velocity boundary layer outside the bubble foot. When the boundary layer thickness was thin, the initial microlayer thickness was determined by the boundary layer thickness, and the initial microlayer thickness proportionally increased with increasing boundary layer thickness. On the other hand, when the boundary layer was thick, the initial microlayer thickness decreased with increasing boundary layer thickness. In this thick boundary layer region, the momentum balance in the dynamic meniscus region became important, in addition to the boundary layer thickness, and the microlayer thickness, made dimensionless using boundary layer thickness, correlated with the Bond number.

  8. Effects of Vapor Path Structures on Critical Heat Flux and Boiling Heat Transfer in Pool Boiling

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Han; Bang, In Cheol [UNIST, Ulsan (Korea, Republic of)

    2016-05-15

    Most of industry areas which have used the boiling heat transfer determine the safety margin of the power systems based on the CHF point. If the power density of the systems exceed the CHF region, the systems will be damaged because vapor films, which have much lower heat transfer capabilities, will cover the heating surface. Therefore, numerous studies related to the CHF prediction models have been extensively studied over the last 60 years, in terms of its physical mechanisms. Hydrodynamic instability, macrolayer dryout, hot/dry spot, and bubble interaction theories have been proposed as the CHF triggering and prediction models. One theory widely used to predict the CHF mechanism is hydrodynamic instability theory proposed by Zuber and modified hydrodynamic theories have been proposed and developed to analyze the CHF enhancement mechanisms. The paper concluded that the RT instability should consider the effect of heater characteristics to predict the CHF values more accurately. The CHF studies related to the hydrodynamic instabilities have been focused on finding the change of the RT instability wavelength and making a relation between the RT instability and KH instability wavelengths, but the effect of the critical height for the vapor path which can represent the KH instability wavelength has not been reported. Therefore, the effect of the critical height of the vapor path was examined using various types of intended vapor path with different heights of the structures. The effect of the vapor path with various heights of the structures was considered in the plate pool boiling facility to find the hydrodynamic instability mechanisms. The critical height of the intended vapor path was found when the height was less than 3 mm. The modified KH instability wavelength by considering numerical constant of the Zuber's prediction model predicted the critical height of the vapor path as the similar value of the experimental results. The results indicated that the

  9. Boiling as household water treatment in Cambodia: a longitudinal study of boiling practice and microbiological effectiveness.

    Science.gov (United States)

    Brown, Joseph; Sobsey, Mark D

    2012-09-01

    This paper focuses on the consistency of use and microbiological effectiveness of boiling as it is practiced in one study site in peri-urban Cambodia. We followed 60 randomly selected households in Kandal Province over 6 months to collect longitudinal data on water boiling practices and effectiveness in reducing Escherichia coli in household drinking water. Despite > 90% of households reporting that they used boiling as a means of drinking water treatment, an average of only 31% of households had boiled water on hand at follow-up visits, suggesting that actual use may be lower than self-reported use. We collected 369 matched untreated and boiled water samples. Mean reduction of E. coli was 98.5%; 162 samples (44%) of boiled samples were free of E. coli (boiled water in a covered container was associated with safer product water than storage in an uncovered container.

  10. Pseudo-Marginal Slice Sampling

    OpenAIRE

    Murray, Iain; Graham, Matthew

    2015-01-01

    Markov chain Monte Carlo (MCMC) methods asymptotically sample from complex probability distributions. The pseudo-marginal MCMC framework only requires an unbiased estimator of the unnormalized probability distribution function to construct a Markov chain. However, the resulting chains are harder to tune to a target distribution than conventional MCMC, and the types of updates available are limited. We describe a general way to clamp and update the random numbers used in a pseudo-marginal meth...

  11. Drop collision with a hot, dry solid substrate: Heat transfer during nucleate boiling

    Science.gov (United States)

    Breitenbach, Jan; Roisman, Ilia V.; Tropea, Cameron

    2017-07-01

    Outcomes from an isothermal drop impact onto a surface (rebound, deposition, or splash) are determined by the impact parameters, liquid material properties, substrate morphology, and wettability. Drop impact onto a hot surface can be accompanied by Marangoni effects, nucleate or film boiling, and evaporation. The main focus of this experimental study is the characterization of the hydrodynamic outcome of a single-drop impact onto a hot surface. Drop impact phenomena have been observed and characterized using a high-speed video system. The impact parameters of the drop and the surface temperature have been varied. The observations lead to a classification of impact outcomes into several regimes: evaporation, nucleate boiling, foaming, transitional boiling, and film boiling. The contact time of the impinging droplet on the surface has been measured, and a model for this time and for the heat flux from the substrate to the drop has been proposed for the nucleate boiling regime. Comparison of model predictions to existing literature data is good.

  12. Partial Nucleate Pool Boiling at Low Heat Flux: Preliminary Ground Test for SOBER-SJ10

    Science.gov (United States)

    Wu, Ke; Li, Zhen-Dong; Zhao, Jian-Fu; Li, Hui-Xiong; Li, Kai

    2016-05-01

    Focusing on partial nucleate pool boiling at low heat flux, SOBER-SJ10, one of 27 experiments of the program SJ-10, has been proposed to study local convection and heat transfer around an isolated growing vapor bubble during nucleate pool boiling on a well characterized flat surface in microgravity. An integrated micro heater has been developed. By using a local pulse overheating method in the experimental mode of single bubble boiling, a bubble nucleus can be excited with accurate spatial and temporal positioning on the top-side of a quartz glass substrate with a thickness of 2 mm and an effective heating area of 4.5 mm in diameter, and then grows under an approximate constant heat input provided by the main heater on the back-side of the substrate. Ten thin film micro-RTDs are used for local temperature measurements on the heating surface underneath the growing bubble. Normal pool boiling experiments can also be carried out with step-by-step increase of heating voltage. A series of ground test of the flight module of SOBER-SJ10 have been conducted. Good agreement of the measured data of single phase natural convection with the common-used empirical correlation warrants reasonable confidence in the data. It is found that the values of the incipience superheat of pool boiling at different subcooling are consistent with each others, verifying that the influence of subcooling on boiling incipience can be neglected. Pool boiling curves are also obtained, which shows great influence of subcooling on heat transfer of partial nucleate pool boiling, particularly in lower heat flux.

  13. Correlation for the Prediction of Flow Boiling Heat Transfer in Small Diameter Tubes

    Science.gov (United States)

    Miyata, Kazushi; Mori, Hideo; Hamamoto, Yoshinori

    The objective of the present study is to develop a correlation applicable to a prediction of an axially local heat transfer coefficient in flow boiling within small diameter tubes. From experimental data of authors obtained previously, it was found that, for the accurate prediction of the heat transfer in small diameter tubes, it was necessary to evaluate precisely the contribution of evaporation heat transfer of thin liquid film around vapor plugs in slug flow, adding to the forced convection heat transfer and nucleate boiling heat transfer. There are, however, only conventional heat transfer correlations which consider any two of the three contributions; forced convection and nucleate boiling in most cases. In this study, a new correlation considering all of three contributions was developed based on data of R 410A by authors and data of other Freons, water and CO2 by other researchers. In the new correlation, the liquid film evaporation heat transfer is evaluated using liquid film thickness correlated with the Capillary number, the forced convection heat transfer is calculated by use of the Dittus-Boelter correlation and the Lockhart-Martinelli parameter, and the nucleate boiling heat transfer is predicted from the Stephan-Abdelsalam correlation with the suppression factor. The new correlation showed higher prediction performance compared with conventional heat transfer correlations.

  14. A study on the upward and downward facing pool boiling heat transfer characteristics of graphene-modified surface

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Hoon; Ahn, Ho Seon [Incheon National Univ., Incheon (Korea, Republic of); Kim, Ji Min [POSTECH, Pohang (Korea, Republic of)

    2016-10-15

    Recently, graphene, carbon in two dimensions, were highlighted as a good heat transfer materials, according to its high thermal conductivity. Lateral conduction and water absorption into the structure helped graphene films to inhibit the formation of hot spots, which means increasing of critical heat flux (CHF) and boiling heat transfer coefficient (BHTC) performances. In this study, we report a promising increase of CHF and BHTC results with 2D graphene films. Furthermore, we tried to observe bubble behavior via high-speed visualization to investigate a relationship between bubble behavior and pool boiling performances in downward facing boiling. The effect of graphene film coating on the pool boiling performances of upward and downward facing heater surface were examined. 2D- and 3D- graphene film showed good enhancement results on the CHF (by 111% and 60%) and BHTC (by 40% and 20-25%) performances. Bubble behavior change was significant factor on the CHF and BHTC performances in downward facing boiling. The amount of evaporation heat flux was calculated from the velocity, bubble diameter, frequency, orientation angle and superheat that the post-products of the high-speed visualization.

  15. Boiling as Household Water Treatment in Cambodia: A Longitudinal Study of Boiling Practice and Microbiological Effectiveness

    OpenAIRE

    Brown, Joseph; Sobsey, Mark D.

    2012-01-01

    This paper focuses on the consistency of use and microbiological effectiveness of boiling as it is practiced in one study site in peri-urban Cambodia. We followed 60 randomly selected households in Kandal Province over 6 months to collect longitudinal data on water boiling practices and effectiveness in reducing Escherichia coli in household drinking water. Despite > 90% of households reporting that they used boiling as a means of drinking water treatment, an average of only 31% of households...

  16. Pseudo-communication vs Quasi-communication

    Directory of Open Access Journals (Sweden)

    Елена Константиновна Черничкина

    2016-12-01

    Full Text Available The article is devoted to the analysis of such specific forms of human interaction as quasi- and pseudo-communication. The authors specify the terms which sometimes are used interchangeably. The aim of the conducted research is to find out and demonstrate existing differences and similarities of these communicative phenomena on the basis of theoretical and empirical analysis of the research material in the Russian and English languages. The authors describe communicative features of these phenomena and consider the reasons for such forms of communication and their increased use at present. The research material is represented fiction extracts, film scripts, jokes, print media, a collection of oral speech records both in Russian and English. The authors make use of the following research methods: definitional analysis (to define the terminology of the research, the method of linguistic observation and introspection (to select the communicative situations, the descriptive-analytical method and the method of comparative analysis (to identify similarities and differences of the target phenomena, and the conversational analysis method (to view productivity and effectiveness of a dialogue, etc. The classification of possible forms of their existence in different discourses is suggested. The authors assume that both pseudo- and quasi-communication are characterized as fictitious forms of human interaction with some noticeable violation of the basic communicative model. Pseudo-communication suffers from the discrepancy of the meaning of a coded and decoded message. The authors put forward the main parameters of scientific classification of it as follows: adequate understanding, intentionality, and the stage of communicative action where the failure takes place. At the same time they stress the necessity to distinguish the cases of pseudo talks from phatic and indirect communication. Quasi-communcation is marked by the lack of a real partner and hence

  17. Estados de pseudo-Cushing

    OpenAIRE

    Romanholi, Daniella J.P.C.; SALGADO, Luiz Roberto

    2007-01-01

    Síndromes de pseudo-Cushing são um grupo heterogêneo de doenças, incluindo alcoolismo, anorexia nervosa, obesidade visceral e depressão, que compartilham muitas das características clínicas e bioquímicas da síndrome de Cushing. Os mecanismos responsáveis para a gênese da síndrome de pseudo-Cushing são fracamente compreendidos. Tem sido sugerido que o hipercortisolismo da síndrome de pseudo-Cushing pode ser resultante do aumento da secreção do hormônio liberador de corticotrofina (CRH) hipotal...

  18. SUPERHEATING IN A BOILING WATER REACTOR

    Science.gov (United States)

    Treshow, M.

    1960-05-31

    A boiling-water reactor is described in which the steam developed in the reactor is superheated in the reactor. This is accomplished by providing means for separating the steam from the water and passing the steam over a surface of the fissionable material which is not in contact with the water. Specifically water is boiled on the outside of tubular fuel elements and the steam is superheated on the inside of the fuel elements.

  19. Numerical simulation of single bubble boiling behavior

    Directory of Open Access Journals (Sweden)

    Junjie Liu

    2017-06-01

    Full Text Available The phenomena of a single bubble boiling process are studied with numerical modeling. The mass, momentum, energy and level set equations are solved using COMSOL multi-physics software. The bubble boiling dynamics, the transient pressure field, velocity field and temperature field in time are analyzed, and reasonable results are obtained. The numeral model is validated by the empirical equation of Fritz and could be used for various applications.

  20. 21 CFR 872.6710 - Boiling water sterilizer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Boiling water sterilizer. 872.6710 Section 872...) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6710 Boiling water sterilizer. (a) Identification. A boiling water sterilizer is an AC-powered device that consists of a container for boiling water...

  1. Surface boiling of superheated liquid

    Energy Technology Data Exchange (ETDEWEB)

    Reinke, P. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-01-01

    A basic vaporization mechanism that possibly affects the qualitative and quantitative prediction of the consequences of accidental releases of hazardous superheated liquids was experimentally and analytically investigated. The studies are of relevance for the instantaneous failure of a containment vessel filled with liquefied gas. Even though catastrophical vessel failure is a rare event, it is considered to be a major technological hazard. Modeling the initial phase of depressurisation and vaporization of the contents is an essential step for the subsequent analysis of the spread and dispersion of the materials liberated. There is only limited understanding of this inertial expansion stage of the superheated liquid, before gravity and atmospheric turbulence begin to dominate the expansion. This work aims at a better understanding of the vaporization process and to supply more precise source-term data. It is also intended to provide knowledge for the prediction of the behavior of large-scale releases by the investigation of boiling on a small scale. Release experiments with butane, propane, R-134a and water were conducted. The vaporization of liquids that became superheated by sudden depressurisation was studied in nucleation-site-free glass receptacles. Several novel techniques for preventing undesired nucleation and for opening the test-section were developed. Releases from pipes and from a cylindrical geometry allowed both linear one-dimensional, and radial-front two-dimensional propagation to be investigated. Releases were made to atmospheric pressure over a range of superheats. It was found that, above a certain superheat temperature, the free surface of the metastable liquid rapidly broke up and ejected a high-velocity vapor/liquid stream. The zone of intense vaporization and liquid fragmentation proceeded as a front that advanced into the test fluids. No nucleation of bubbles in the bulk of the superheated liquid was observed. (author) figs., tabs., refs.

  2. Two-phase structure above hot surfaces in jet impingement boiling

    Science.gov (United States)

    Bogdanic, L.; Auracher, H.; Ziegler, F.

    2009-05-01

    Jet impingement boiling is very efficient in cooling of hot surfaces as a part of the impinging liquid evaporates. Several studies have been carried out to measure and correlate the heat transfer to impinging jets as a function of global parameters such as jet subcooling, jet velocity, nozzle size and distance to the surface, etc. If physically based mechanistic models are to be developed, studies on the fundamentals of two-phase dynamics near the hot surface are required. In the present study the vapor-liquid structures underneath a subcooled (20 K) planar (1 mm × 9 mm) water jet, impinging the heated plate vertically with a velocity of 0.4 m/s, were analyzed by means of a miniaturized optical probe. It has a tip diameter of app. 1.5 μm and is moved toward the plate by a micrometer device. The temperature controlled experimental technique enabled steady-state experiments in all boiling regimes. The optical probe data provides information about the void fraction, the contact frequencies and the distribution of the vapor and liquid contact times as a function of the distance to the surface. The measured contact frequencies range from 40 Hz at the onset of nucleate boiling to nearly 20,000 Hz at the end of the transition boiling regime. Due to condensation in the subcooled jet vapor disappears at a distance to the surface of app. 1.2 mm in nucleate boiling. This vapor layer becomes smaller with increasing wall superheat. In film boiling a vapor film thickness of 8 ± 2 μm was found.

  3. Pseudo-Weak-R0 Algebras

    Directory of Open Access Journals (Sweden)

    Yong Lin Liu

    2014-01-01

    Full Text Available A positive answer to the open problem of Iorgulescu on extending weak-R0 algebras and R0-algebras to the noncommutative forms is given. We show that pseudo-weak-R0 algebras are categorically isomorphic to pseudo-IMTL algebras and that pseudo-R0 algebras are categorically isomorphic to pseudo-NM algebras. Some properties, the noncommutative forms of the properties in weak-R0 algebras and R0-algebras, are investigated. The simplified axiom systems of pseudo-weak-R0 algebras and pseudo-R0 algebras are obtained.

  4. Exending pseudo-arcs in odd characteristic

    OpenAIRE

    Penttila, Tim; Van de Voorde, Geertrui

    2015-01-01

    A {\\em pseudo-arc} in $\\mathrm{PG}(3n-1,q)$ is a set of $(n-1)$-spaces such that any three of them span the whole space. A pseudo-arc of size $q^n+1$ is a {\\em pseudo-oval}. If a pseudo-oval $\\mathcal{O}$ is obtained by applying field reduction to a conic in $\\mathrm{PG}(2,q^n)$, then $\\mathcal{O}$ is called a {\\em pseudo-conic}. We first explain the connection of (pseudo-)arcs with Laguerre planes, orthogonal arrays and generalised quadrangles. In particular, we prove that the Ahrens-Szekere...

  5. A high-fidelity approach towards heat transfer prediction of pool boiling

    Science.gov (United States)

    Yazdani, Miad; Alahyari, Abbas; Radcliff, Thomas

    2014-11-01

    A novel numerical approach is developed to simulate the multiscale problem of pool-boiling phase change with an unprecedented fidelity and cost. The particular focus is to predict the heat transfer coefficient of pool-boiling regime and its transition to critical heat flux on surfaces of arbitrary shape and roughness distribution. The large-scale of the phase change and bubble dynamics is addressed through employing off-the-shelf methods for interface tracking and interphase mass and energy transfer. The small-scale of the microlayer which forms at early stage of bubble nucleation is resolved through asymptotic approximation of the thin-film theory which provides a closed-form solution for the distribution of the micro-layer and its influence on the evaporation process. In addition, the surface roughness and its role in bubble nucleation and growth is represented based on thermodynamics of nucleation process which allows the simulation of pool boiling on any surface with known roughness and enhancement characteristics. The numerical model is validated for dynamics and hydrothermal characteristics of a single nucleated bubble on a flat surface against available literature data. In addition, the model's prediction of pool-boiling heat transfer coefficient is verified against reputable correlations for various roughness distributions and different surface alignment. Finally, the model is employed to demonstrate pool-boiling phenomenon on enhanced structures with reentrance cavities and to explore the effect of enhancement features on thermal and hydrodynamic characteristics of these surfaces.

  6. Cryogenic Boil-Off Reduction System

    Science.gov (United States)

    Plachta, David W.; Guzik, Monica C.

    2014-03-01

    A computational model of the cryogenic boil-off reduction system being developed by NASA as part of the Cryogenic Propellant Storage and Transfer technology maturation project has been applied to a range of propellant storage tanks sizes for high-performing in-space cryogenic propulsion applications. This effort focuses on the scaling of multi-layer insulation (MLI), cryocoolers, broad area cooling shields, radiators, solar arrays, and tanks for liquid hydrogen propellant storage tanks ranging from 2 to 10 m in diameter. Component scaling equations were incorporated into the Cryogenic Analysis Tool, a spreadsheet-based tool used to perform system-level parametric studies. The primary addition to the evolution of this updated tool is the integration of a scaling method for reverse turbo-Brayton cycle cryocoolers, as well as the development and inclusion of Self-Supporting Multi-Layer Insulation. Mass, power, and sizing relationships are traded parametrically to establish the appropriate loiter period beyond which this boil-off reduction system application reduces mass. The projected benefit compares passive thermal control to active thermal control, where active thermal control is evaluated for reduced boil-off with a 90 K shield, zero boil-off with a single heat interception stage at the tank wall, and zero boil-off with a second interception stage at a 90 K shield. Parametric studies show a benefit over passive storage at loiter durations under one month, in addition to showing a benefit for two-stage zero boil-off in terms of reducing power and mass as compared to single stage zero boil-off. Furthermore, active cooling reduces the effect of varied multi-layer insulation performance, which, historically, has been shown to be significant.

  7. Single-bubble dynamics in pool boiling of one-component fluids

    KAUST Repository

    Xu, Xinpeng

    2014-06-04

    We numerically investigate the pool boiling of one-component fluids with a focus on the effects of surface wettability on the single-bubble dynamics. We employed the dynamic van der Waals theory [Phys. Rev. E 75, 036304 (2007)], a diffuse-interface model for liquid-vapor flows involving liquid-vapor transition in nonuniform temperature fields. We first perform simulations for bubbles on homogeneous surfaces. We find that an increase in either the contact angle or the surface superheating can enhance the bubble spreading over the heating surface and increase the bubble departure diameter as well and therefore facilitate the transition into film boiling. We then examine the dynamics of bubbles on patterned surfaces, which incorporate the advantages of both hydrophobic and hydrophilic surfaces. The central hydrophobic region increases the thermodynamic probability of bubble nucleation while the surrounding hydrophilic region hinders the continuous bubble spreading by pinning the contact line at the hydrophobic-hydrophilic intersection. This leads to a small bubble departure diameter and therefore prevents the transition from nucleate boiling into film boiling. With the bubble nucleation probability increased and the bubble departure facilitated, the efficiency of heat transfer on such patterned surfaces is highly enhanced, as observed experimentally [Int. J. Heat Mass Transfer 57, 733 (2013)]. In addition, the stick-slip motion of contact line on patterned surfaces is demonstrated in one-component fluids, with the effect weakened by surface superheating.

  8. Structural Changes of Malt Proteins During Boiling

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available Changes in the physicochemical properties and structure of proteins derived from two malt varieties (Baudin and Guangmai during wort boiling were investigated by differential scanning calorimetry, SDS-PAGE, two-dimensional electrophoresis, gel filtration chromatography and circular dichroism spectroscopy. The results showed that both protein content and amino acid composition changed only slightly during boiling, and that boiling might cause a gradual unfolding of protein structures, as indicated by the decrease in surface hydrophobicity and free sulfhydryl content and enthalpy value, as well as reduced α-helix contents and markedly increased random coil contents. It was also found that major component of both worts was a boiling-resistant protein with a molecular mass of 40 kDa, and that according to the two-dimensional electrophoresis and SE-HPLC analyses, a small amount of soluble aggregates might be formed via hydrophobic interactions. It was thus concluded that changes of protein structure caused by boiling that might influence beer quality are largely independent of malt variety.

  9. Film

    OpenAIRE

    Balint, Ruth; Dolgopolov, Greg

    2008-01-01

    From the beginning of the twentieth century, Sydney defined cosmopolitanism and modernity in the national imagination, and central to this image was the cinema: its technology, its architecture, its stars, its marketing and the stories it circulated to its audiences about Australia and the world. Though it is difficult to define a genre of Sydney film, Sydney provided the backdrop for a host of ideas about the city, and later suburbia. Sydney came to be seen as a ‘tinsel town’ of cultural ban...

  10. NUCLEAR SUPERHEATER FOR BOILING WATER REACTOR

    Science.gov (United States)

    Holl, R.J.; Klecker, R.W.; Graham, C.B.

    1962-05-15

    A description is given of a boiling water reactor having a superheating region integral with the core. The core consists essentially of an annular boiling region surrounding an inner superheating region. Both regions contain fuel elements and are separated by a cylindrical wall, perforations being provided in the lower portion of the cylindrical wall to permit circulation of a common water moderator between the two regions. The superheater region comprises a plurality of tubular fuel assemblies through which the steam emanating from the boiling region passes to the steam outlet. Each superheater fuel assembly has an outer double-walled cylinder, the double walls being concentrically spaced and connected together at their upper ends but open at the bottom to provide for differential thermal expansion of the inner and outer walls. Gas is entrapped in the annulus between the walls which acts as an insulating space between the fissionable material inside and the moderator outside. (AEC)

  11. Corrosion Behavior of Amorphous Nickel-Base Alloys in a Boiling Concentrated Sodium Hydroxide Solution

    OpenAIRE

    Kazuo, SHIMAMURA; Kimikado, MIURA; Asahi, Kawashima; Katsuhiko, Asami; Koji, Hashimoto; Institute for Materials Research:Mitsui Engineering & Shipbuilding Co., Ltd.; Institute for Materials Research

    1988-01-01

    Polarization curves were measured in a boiling 50% NaOH solution, and the specimen surface was analyzed by X-ray photoelectron spectroscopy. A combined addition of chromium and molybdenum to amorphous nickel-phosphorus alloys significantly enhances the corrosion resistance. Addition of copper and lead are also effective in improving the corrosion resistance. The surface film formed on amorphous nickel-base alloys consists mainly of hydrated nickel oxyhydroxide. Chromium is concentrated in the...

  12. Heat transfer coefficient for boiling carbon dioxide

    DEFF Research Database (Denmark)

    Knudsen, Hans Jørgen Høgaard; Jensen, Per Henrik

    1998-01-01

    Heat transfer coefficient and pressure drop for boiling carbon dioxide (R744) flowing in a horizontal pipe has been measured. The calculated heat transfer coeeficient has been compared with the Chart correlation of Shah. The Chart Correlation predits too low heat transfer coefficient but the ratio...

  13. Big Bubbles in Boiling Liquids: Students' Views

    Science.gov (United States)

    Costu, Bayram

    2008-01-01

    The aim of this study was to elicit students' conceptions about big bubbles in boiling liquids (water, ethanol and aqueous CuSO[subscript 4] solution). The study is based on twenty-four students at different ages and grades. The clinical interviews technique was conducted to solicit students' conceptions and the interviews were analyzed to…

  14. An Investigation of Graduate Scientists' Understandings of Evaporation and Boiling.

    Science.gov (United States)

    Goodwin, Alan; Orlik, Yuri

    2000-01-01

    Uses a video presentation of six situations relating to the evaporation and boiling of liquids and the escape of dissolved gases from solution and investigates graduate scientists' understanding of the concepts of boiling and evaporation. (Author/YDS)

  15. Flow boiling in microgap channels experiment, visualization and analysis

    CERN Document Server

    Alam, Tamanna; Jin, Li-Wen

    2013-01-01

    Flow Boiling in Microgap Channels: Experiment, Visualization and Analysis presents an up-to-date summary of the details of the confined to unconfined flow boiling transition criteria, flow boiling heat transfer and pressure drop characteristics, instability characteristics, two phase flow pattern and flow regime map and the parametric study of microgap dimension. Advantages of flow boiling in microgaps over microchannels are also highlighted. The objective of this Brief is to obtain a better fundamental understanding of the flow boiling processes, compare the performance between microgap and c

  16. Pseudo random signal processing theory and application

    CERN Document Server

    Zepernick, Hans-Jurgen

    2013-01-01

    In recent years, pseudo random signal processing has proven to be a critical enabler of modern communication, information, security and measurement systems. The signal's pseudo random, noise-like properties make it vitally important as a tool for protecting against interference, alleviating multipath propagation and allowing the potential of sharing bandwidth with other users. Taking a practical approach to the topic, this text provides a comprehensive and systematic guide to understanding and using pseudo random signals. Covering theoretical principles, design methodologies and applications

  17. Unorthodox bubbles when boiling in cold water

    Science.gov (United States)

    Parker, Scott; Granick, Steve

    2014-01-01

    High-speed movies are taken when bubbles grow at gold surfaces heated spotwise with a near-infrared laser beam heating water below the boiling point (60-70 °C) with heating powers spanning the range from very low to so high that water fails to rewet the surface after bubbles detach. Roughly half the bubbles are conventional: They grow symmetrically through evaporation until buoyancy lifts them away. Others have unorthodox shapes and appear to contribute disproportionately to heat transfer efficiency: mushroom cloud shapes, violently explosive bubbles, and cavitation events, probably stimulated by a combination of superheating, convection, turbulence, and surface dewetting during the initial bubble growth. Moreover, bubbles often follow one another in complex sequences, often beginning with an unorthodox bubble that stirs the water, followed by several conventional bubbles. This large dataset is analyzed and discussed with emphasis on how explosive phenomena such as cavitation induce discrepancies from classical expectations about boiling.

  18. Boiling point of volatile liquids at various pressures

    Directory of Open Access Journals (Sweden)

    Luisa Maria Valencia

    2017-07-01

    Full Text Available Water, under normal conditions, tends to boil at a “normal boiling temperature” at which the atmospheric pressure fixes the average amount of kinetic energy needed to reach its boiling point. Yet, the normal boiling temperature of different substances varies depending on their nature, for which substances like alcohols, known as volatile, boil faster than water under same conditions. In response to this phenomenon, an investigation on the coexistence of both gas and liquid phases of a volatile substance in a closed system was made, establishing vapor pressure as the determining tendency of a substance to vaporize, which increases exponentially with temperature until a critical point is reached. Since atmospheric pressure is fixed, the internal pressure of the system was varied to determine its relationship with vapor pressure and thus with the boiling point of the substance, concluding that the internal pressure and boiling point of a volatile liquid in a closed system are negatively proportional.

  19. Steady State Vapor Bubble in Pool Boiling.

    Science.gov (United States)

    Zou, An; Chanana, Ashish; Agrawal, Amit; Wayner, Peter C; Maroo, Shalabh C

    2016-02-03

    Boiling, a dynamic and multiscale process, has been studied for several decades; however, a comprehensive understanding of the process is still lacking. The bubble ebullition cycle, which occurs over millisecond time-span, makes it extremely challenging to study near-surface interfacial characteristics of a single bubble. Here, we create a steady-state vapor bubble that can remain stable for hours in a pool of sub-cooled water using a femtosecond laser source. The stability of the bubble allows us to measure the contact-angle and perform in-situ imaging of the contact-line region and the microlayer, on hydrophilic and hydrophobic surfaces and in both degassed and regular (with dissolved air) water. The early growth stage of vapor bubble in degassed water shows a completely wetted bubble base with the microlayer, and the bubble does not depart from the surface due to reduced liquid pressure in the microlayer. Using experimental data and numerical simulations, we obtain permissible range of maximum heat transfer coefficient possible in nucleate boiling and the width of the evaporating layer in the contact-line region. This technique of creating and measuring fundamental characteristics of a stable vapor bubble will facilitate rational design of nanostructures for boiling enhancement and advance thermal management in electronics.

  20. Flow boiling test of GDP replacement coolants

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.H. [comp.

    1995-08-01

    The tests were part of the CFC replacement program to identify and test alternate coolants to replace CFC-114 being used in the uranium enrichment plants at Paducah and Portsmouth. The coolants tested, C{sub 4}F{sub 10} and C{sub 4}F{sub 8}, were selected based on their compatibility with the uranium hexafluoride process gas and how well the boiling temperature and vapor pressure matched that of CFC-114. However, the heat of vaporization of both coolants is lower than that of CFC-114 requiring larger coolant mass flow than CFC-114 to remove the same amount of heat. The vapor pressure of these coolants is higher than CFC-114 within the cascade operational range, and each coolant can be used as a replacement coolant with some limitation at 3,300 hp operation. The results of the CFC-114/C{sub 4}F{sub 10} mixture tests show boiling heat transfer coefficient degraded to a minimum value with about 25% C{sub 4}F{sub 10} weight mixture in CFC-114 and the degree of degradation is about 20% from that of CFC-114 boiling heat transfer coefficient. This report consists of the final reports from Cudo Technologies, Ltd.

  1. Pseudo-complex general relativity

    CERN Document Server

    Hess, Peter O; Greiner, Walter

    2016-01-01

    This volume presents an pseudo-complex extension of General Relativity which addresses these issues and presents proposals for experimental examinations in strong fields near a large mass. General Relativity is a beautiful and well tested theory of gravitation. Nevertheless, it implies conceptual problems like the creation of singularities (Black Holes) as a result of the collapse of large masses, or the appearance of event horizons which exclude parts of the space-time from the observation of external observers. The mathematical and geometrical foundations of this extension are displayed in detail, and applications including orbits and accretion disks around large central masses, neutron stars or cosmological models are introduced. Calculations both for classical and extended applications are often executed in the form of problems with extensive solutions, which makes this volume also a valuable resource for any student of General Relativity.

  2. Acroangiodermatitis (Pseudo-Kaposi sarcoma

    Directory of Open Access Journals (Sweden)

    Satyendra Kumar Singh

    2014-01-01

    Full Text Available Acroangiodermatitis or Pseudo-Kaposi sarcoma is a rare angioproliferative entity, related to chronic venous insufficiency or certain other vascular anomalies. It is often associated with chronic venous insufficiency, arteriovenous malformation of the legs, chronic renal failure treated with dialysis, paralyzed legs and amputation stumps. We hereby describe a case of 45 year old female presenting with pitting pedal edema, multiple ulcers over bilateral lower limbs with irregular margins with erythema and hyperpigmentation of the surrounding skin. Color Doppler study of bilateral lower limbs was normal. Histopathological examination from one of the lesions showed hyperplastic epidermis, proliferation of capillaries in dermis, hemosiderin deposits and lymphocytic infiltrate. These features thus confirmed the diagnosis of Acroangiodermatitis.

  3. Boiling phenomena in near-critical SF6 observed in weightlessness

    Science.gov (United States)

    Lecoutre, Carole; Garrabos, Yves; Beysens, Daniel; Nikolayev, Vadim; Hahn, Inseob

    2014-07-01

    Boiling phenomena in the two-phase region of SF6 close to its critical point have been observed using the high-quality thermal and optical environment of the CNES dedicated facility ALI-DECLIC on board the International Space Station (ISS). The weightlessness environment of the fluid, which cancels buoyancy forces and favorites the three-dimensional spherical shape of the gas bubble, is proven to be an irreplaceable powerful tool for boiling studies. To identify each key mechanism of the boiling phenomena, the ALI-DECLIC experiments have benefited from (i) the well-adapted design of the test cells, (ii) the high-fidelity of the ALI insert teleoperation when long-duration experiment in stable thermal and microgravity environment are required and (iii) the high repeatability of the controlled thermal disturbances. These key mechanisms were observed by light transmission and interferometry technique independently with two sample cells filled with pure SF6 at a near-critical density. The fluid samples are driven away from thermal equilibrium by using a heater directly implemented in the fluid, or a surface heater on a sapphire optical window. In the interferometry cell, the bulk massive heater distinguishes two symmetrical two-phase domains. The modification of the gas bubble shape is observed during heating. In the direct observation cell, the gas bubble is separated by a liquid film from the thin layered transparent heater deposited on the sapphire window. The liquid film drying and the triple contact line motion during heating are observed using light transmission. The experiments have been performed in a temperature range of 10 K below the critical temperature Tc, with special attention to the range 0.1 mK≤T-T≤3 mK very close to the critical temperature. The unique advantage of this investigation is to provide opportunities to observe the boiling phenomena at very low heat fluxes, thanks to the fine adjustment of the liquid-vapor properties, (e.g. surface

  4. An analytic model of pool boiling critical heat flux on an immerged downward facing curved surface

    Energy Technology Data Exchange (ETDEWEB)

    He, Hui; Pan, Liang-ming, E-mail: cneng@cqu.edu.cn; Wu, Yao; Chen, De-qi

    2015-08-15

    Highlights: • Thin liquid film and supplement of liquid contribute to the CHF. • CHF increases from the bottom to the upper of the lowerhead. • Evaporation of thin liquid film is dominant nearby bottom region. • The subcooling has significant effects on the CHF. - Abstract: In this paper, an analytical model of the critical heat flux (CHF) on the downward facing curved surface for pool boiling has been proposed, which hypothesizes that the CHF on the downward facing curved is composed of two parts, i.e. the evaporation of the thin liquid film underneath the elongated bubble adhering to the lower head outer surface and the depletion of supplement of liquid due to the relative motion of vapor bubbles along with the downward facing curved. The former adopts the Kelvin–Helmholtz instability analysis of vapor–liquid interface of the vapor jets which penetrating in the thin liquid film. When the heat flux closing to the CHF point, the vapor–liquid interface becomes highly distorted, which block liquid to feed the thin liquid film and the thin liquid film will dry out gradually. While the latter considers that the vapor bubbles move along with the downward facing curved surface, and the liquid in two-phase boundary layer enter the liquid film that will be exhausted when the CHF occurs. Based on the aforementioned mechanism and the energy balance between the thin liquid film evaporation and water feeding, and taking the subcooling of the bulk water into account, the mathematic model about the downward facing curved surface CHF has been proposed. The CHF of the downward facing curved surface for pool boiling increases along with the downward facing orientation except in the vicinity of bottom center region, because in this region the vapor bubble almost stagnates and the evaporation of the thin liquid film is dominant. In addition, the subcooling has significant effect on the CHF. Comparing the result of this model with the published experimental results show

  5. POPULATION DYNAMICS OF PSEUDO-NITZSCHIA SPECIES ...

    African Journals Online (AJOL)

    nb

    ABSTRACT. The genus Pseudo-nitzschia is a chain-forming diatom comprising about 30 species some of which are known to produce domoic acid (DA) that causes amnesic shellfish poisoning (ASP). The current study aimed at assessing the population dynamics of Pseudo-nitzschia in the near shore waters of Dar es ...

  6. Population dynamics of Pseudo-nitzschia species ...

    African Journals Online (AJOL)

    The genus Pseudo-nitzschia is a chain-forming diatom comprising about 30 species some of which are known to produce domoic acid (DA) that causes amnesic shellfish poisoning (ASP). The current study aimed at assessing the population dynamics of Pseudo-nitzschia in the near shore waters of Dar es Salaam. Samples ...

  7. Subadditive functions and their (pseudo-)inverses

    DEFF Research Database (Denmark)

    Østerdal, Lars Peter

    2006-01-01

    The paper considers non-negative increasing functions on intervals with left endpoint closed at zero and investigates the duality between subadditivity and superadditivity via the inverse function and pseudo-inverses......The paper considers non-negative increasing functions on intervals with left endpoint closed at zero and investigates the duality between subadditivity and superadditivity via the inverse function and pseudo-inverses...

  8. Boiling radial flow in fractures of varying wall porosity

    Energy Technology Data Exchange (ETDEWEB)

    Barnitt, Robb Allan

    2000-06-01

    The focus of this report is the coupling of conductive heat transfer and boiling convective heat transfer, with boiling flow in a rock fracture. A series of experiments observed differences in boiling regimes and behavior, and attempted to quantify a boiling convection coefficient. The experimental study involved boiling radial flow in a simulated fracture, bounded by a variety of materials. Nonporous and impermeable aluminum, highly porous and permeable Berea sandstone, and minimally porous and permeable graywacke from The Geysers geothermal field. On nonporous surfaces, the heat flux was not strongly coupled to injection rate into the fracture. However, for porous surfaces, heat flux, and associated values of excess temperature and a boiling convection coefficient exhibited variation with injection rate. Nucleation was shown to occur not upon the visible surface of porous materials, but a distance below the surface, within the matrix. The depth of boiling was a function of injection rate, thermal power supplied to the fracture, and the porosity and permeability of the rock. Although matrix boiling beyond fracture wall may apply only to a finite radius around the point of injection, higher values of heat flux and a boiling convection coefficient may be realized with boiling in a porous, rather than nonporous surface bounded fracture.

  9. Boiling on a tube bundle: heat transfer, pressure drop and flow patterns

    Energy Technology Data Exchange (ETDEWEB)

    Royen Van, E.

    2011-11-15

    The complexity of two-phase flow boiling on a tube bundle presents many challenges to the understanding of the physical phenomena taking place. It is important to quantify these numerous heat flow mechanisms in order to better describe the performance of tube bundles as a function of the operational conditions. In the present study, the bundle boiling facility at the Laboratory of Heat and Mass Transfer (LTCM) was modified to obtain high-speed videos to characterise the two-phase regimes and some bubble dynamics of the boiling process. It was then used to measure heat transfer on single tubes and in bundle boiling conditions. Pressure drop measurements were also made during adiabatic and diabatic bundle conditions. New enhanced boiling tubes from Wolverine Tube Inc. (Turbo-B5) and the Wieland-Werke AG (Gewa-B5) were investigated using R134a and R236fa as test fluids. The tests were carried out at saturation temperatures T{sub sat} of 5 °C and 15 °C, mass flow rates from 4 to 35 kg/m{sup 2}s and heat fluxes from 15 to 70 kW/m{sup 2}, typical of actual operating conditions. The flow pattern investigation was conducted using visual observations from a borescope inserted in the middle of the bundle. Measurements of the light attenuation of a laser beam through the intertube two-phase flow and local pressure fluctuations with piezo-electric pressure transducers were also taken to further help in characterising the complex flow. Pressure drop measurements and data reduction procedures were revised and used to develop new, improved frictional pressure drop prediction methods for adiabatic and diabatic two-phase conditions. The physical phenomena governing the enhanced tube evaporation process and their effects on the performance of tube bundles were investigated and insight gained. A new method based on a theoretical analysis of thin film evaporation was used to propose a new correlating parameter. A large new database of local heat transfer coefficients were obtained

  10. Explosive Boiling in Z-pinch Plasmas*

    Science.gov (United States)

    de Groot, John S.; Bauer, Bruno S.

    2002-11-01

    Recently, high resolution x-ray backlighting (radiography), experiments [1] have shown complex small-scale (typical sizes of 2-30 µm) structure of the exploding wire cores of both single-wire and multiwire loads subjected to 2-5 kA per 7.5-25 µm diameter wire for 1µs. The radiographs show features implying that the core has become a foam-like, liquid-vapor mixture. This foam-like state is apparently caused by explosive boiling. The point is that the wires are heated so rapidly that normal boiling (vapor bubbles are formed heterogeneously in the liquid) cannot occur. In explosive boiling, the liquid is superheated to a temperature close to the critical temperature and the phase change occurs explosively in times as short as a few ns. Homogeneous bubble nucleation occurs and the wire makes a very rapid transition from superheated liquid to a mixture of vapor and liquid droplets. This behavior will have very important effects on wire initiation in Z-pinch driven wire arrays and breakdown in MITLs. The ablation of the wire to form the coronal plasma and the remaining core plasma will be quite different for the mixed state. The mixed state is not modeled in the MHD codes that are being used to model wire initiation. We are developing models of the mixed state to include in the MHD codes. We are also developing experiments to improve the understanding of this curious state of matter. 1. Pikuz, S. A., Shelkovenko, T. A., Sinars, D. B., Greenly, J. B., Dimant, Y. S., and Hammer, D. A., Phys. Rev. Letters 83, 4313-4316 (1999). *Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the United States Department of Energy Under Contract DE-AC04-94AL85000.

  11. Water boiling inside carbon nanotubes: toward efficient drug release.

    Science.gov (United States)

    Chaban, Vitaly V; Prezhdo, Oleg V

    2011-07-26

    We show using molecular dynamics simulation that spatial confinement of water inside carbon nanotubes (CNTs) substantially increases its boiling temperature and that a small temperature growth above the boiling point dramatically raises the inside pressure. Capillary theory successfully predicts the boiling point elevation down to 2 nm, below which large deviations between the theory and atomistic simulation take place. Water behaves qualitatively different inside narrow CNTs, exhibiting transition into an unusual phase, where pressure is gas-like and grows linearly with temperature, while the diffusion constant is temperature-independent. Precise control over boiling by CNT diameter, together with the rapid growth of inside pressure above the boiling point, suggests a novel drug delivery protocol. Polar drug molecules are packaged inside CNTs; the latter are delivered into living tissues and heated by laser. Solvent boiling facilitates drug release.

  12. Boiling heat transfer modern developments and advances

    CERN Document Server

    Lahey, Jr, RT

    2013-01-01

    This volume covers the modern developments in boiling heat transfer and two-phase flow, and is intended to provide industrial, government and academic researchers with state-of-the-art research findings in the area of multiphase flow and heat transfer technology. Special attention is given to technology transfer, indicating how recent significant results may be used for practical applications. The chapters give detailed technical material that will be useful to engineers and scientists who work in the field of multiphase flow and heat transfer. The authors of all chapters are members of the

  13. Heat transfer coeffcient for boiling carbon dioxide

    DEFF Research Database (Denmark)

    Knudsen, Hans Jørgen Høgaard; Jensen, Per Henrik

    1997-01-01

    Heat transfer coefficient and pressure drop for boiling carbon dioxide (R744) flowing in a horizontal pipe has been measured. The pipe is heated by condensing R22 outside the pipe. The heat input is supplied by an electrical heater wich evaporates the R22. With the heat flux assumed constant over...... the whole surface and with measured temperature difference between the inner surface and the evaporation temperature a mean heat transfer coefficient is calculated. The calculated heat transfer coefficient has been compared with the Chart Correlation of Shah. The Chart Correlation predicts too low heat...

  14. Pool boiling visualization on open microchannel surfaces

    Directory of Open Access Journals (Sweden)

    Kaniowski Robert

    2017-01-01

    Full Text Available The paper presents visualization investigations into pool boiling heat transfer for open minichannel surfaces. The experiments were carried out wih saturated water at atmospheric pressure. Parallel microchannels fabricated by machining were about 0.3 mm wide and 0.2 to 0.4 mm deep. High-speed videos were used as an aid to understanding the heat transfer mechanism. The visualization study aimed at identifying nucleation sites of the departing bubbles and determining their diameters and frequency at various superheats.

  15. An experimental investigation of liquid methane convection and boiling in rocket engine cooling channels

    Science.gov (United States)

    Trujillo, Abraham Gerardo

    In the past decades, interest in developing hydrocarbon-fueled rocket engines for deep spaceflight missions has continued to grow. In particular, liquid methane (LCH4) has been of interest due to the weight efficiency, storage, and handling advantages it offers over several currently used propellants. Deep space exploration requires reusable, long life rocket engines. Due to the high temperatures reached during combustion, the life of an engine is significantly impacted by the cooling system's efficiency. Regenerative (regen) cooling is presented as a viable alternative to common cooling methods such as film and dump cooling since it provides improved engine efficiency. Due to limited availability of experimental sub-critical liquid methane cooling data for regen engine design, there has been an interest in studying the heat transfer characteristics of the propellant. For this reason, recent experimental studies at the Center for Space Exploration Technology Research (cSETR) at the University of Texas at El Paso (UTEP) have focused on investigating the heat transfer characteristics of sub-critical CH4 flowing through sub-scale cooling channels. To conduct the experiments, the csETR developed a High Heat Flux Test Facility (HHFTF) where all the channels are heated using a conduction-based thermal concentrator. In this study, two smooth channels with cross sectional geometries of 1.8 mm x 4.1 mm and 3.2 mm x 3.2 mm were tested. In addition, three roughened channels all with a 3.2 mm x 3.2 mm square cross section were also tested. For the rectangular smooth channel, Reynolds numbers ranged between 68,000 and 131,000, while the Nusselt numbers were between 40 and 325. For the rough channels, Reynolds numbers ranged from 82,000 to 131,000, and Nusselt numbers were between 65 and 810. Sub-cooled film-boiling phenomena were confirmed for all the channels presented in this work. Film-boiling onset at Critical Heat Flux (CHF) was correlated to a Boiling Number (Bo) of

  16. Water Boiling inside Carbon Nanotubes: Towards Efficient Drug Release

    OpenAIRE

    Chaban, Vitaly V.; Prezhdo, Oleg V.

    2012-01-01

    We show using molecular dynamics simulation that spatial confinement of water inside carbon nanotubes (CNT) substantially increases its boiling temperature and that a small temperature growth above the boiling point dramatically raises the inside pressure. Capillary theory successfully predicts the boiling point elevation down to 2 nm, below which large deviations between the theory and atomistic simulation take place. Water behaves qualitatively different inside narrow CNTs, exhibiting trans...

  17. Pseudo-Haptic Feedback in Teleoperation.

    Science.gov (United States)

    Neupert, Carsten; Matich, Sebastian; Scherping, Nick; Kupnik, Mario; Werthschutzky, Roland; Hatzfeld, Christian

    2016-01-01

    In this paper, we develop possible realizations of pseudo-haptic feedback in teleoperation systems based on existing works for pseudo-haptic feedback in virtual reality and the intended applications. We derive four potential factors affecting the performance of haptic feedback (calculation operator, maximum displacement, offset force, and scaling factor), which are analyzed in three compliance identification experiments. First, we analyze the principle usability of pseudo-haptic feedback by comparing information transfer measures for teleoperation and direct interaction. Pseudo-haptic interaction yields well above-chance performance, while direct interaction performs almost perfectly. In order to optimize pseudo-haptic feedback, in the second study we perform a full-factorial experimental design with 36 subjects performing 6,480 trials with 36 different treatments. Information transfer ranges from 0.68 bit to 1.72 bit in a task with a theoretical maximum of 2.6 bit, with a predominant effect of the calculation operator and a minor effect of the maximum displacement. In a third study, short- and long-term learning effects are analyzed. Learning effects regarding the performance of pseudo-haptic feedback cannot be observed for single-day experiments. Tests over 10 days show a maximum increase in information transfer of 0.8 bit. The results show the feasibility of pseudo-haptic feedback for teleoperation and can be used as design basis for task-specific systems.

  18. Modal control of unstable boiling states in three-dimensional nonlinear pool-boiling

    NARCIS (Netherlands)

    van Gils, R.W.; Speetjens, M.F.M; Zwart, Heiko J.; Nijmeijer, H.

    2014-01-01

    Topic is feedback stabilisation of a nonlinear pool-boiling system in three spatial dimensions (3D). Regulation of its unstable (non-uniform) equilibria has great potential for application in micro-electronics cooling and thermal-management systems. Here, as a first step, stabilisation of such 3D

  19. Free convection film flows and heat transfer

    CERN Document Server

    Shang, Deyi

    2010-01-01

    Presents development of systematic studies for hydrodynamics and heat and mass transfer in laminar free convection, accelerating film boiling and condensation of Newtonian fluids, and accelerating film flow of non-Newtonian power-law fluids. This book provides a system of analysis models with a developed velocity component method.

  20. Pseudo-periodic partitions of biological sequences.

    Science.gov (United States)

    Li, Lugang; Jin, Renchao; Kok, Poh-Lin; Wan, Honghui

    2004-02-12

    Algorithm development for finding typical patterns in sequences, especially multiple pseudo-repeats (pseudo-periodic regions), is at the core of many problems arising in biological sequence and structure analysis. In fact, one of the most significant features of biological sequences is their high quasi-repetitiveness. Variation in the quasi-repetitiveness of genomic and proteomic texts demonstrates the presence and density of different biologically important information. It is very important to develop sensitive automatic computational methods for the identification of pseudo-periodic regions of sequences through which we can infer, describe and understand biological properties, and seek precise molecular details of biological structures, dynamics, interactions and evolution. We develop a novel, powerful computational tool for partitioning a sequence to pseudo-periodic regions. The pseudo-periodic partition is defined as a partition, which intuitively has the minimal bias to some perfect-periodic partition of the sequence based on the evolutionary distance. We devise a quadratic time and space algorithm for detecting a pseudo-periodic partition for a given sequence, which actually corresponds to the shortest path in the main diagonal of the directed (acyclic) weighted graph constructed by the Smith-Waterman self-alignment of the sequence. We use several typical examples to demonstrate the utilization of our algorithm and software system in detecting functional or structural domains and regions of proteins. A big advantage of our software program is that there is a parameter, the granularity factor, associated with it and we can freely choose a biological sequence family as a training set to determine the best parameter. In general, we choose all repeats (including many pseudo-repeats) in the SWISS-PROT amino acid sequence database as a typical training set. We show that the granularity factor is 0.52 and the average agreement accuracy of pseudo-periodic partitions

  1. Zero boil-off system testing

    Science.gov (United States)

    Plachta, D. W.; Johnson, W. L.; Feller, J. R.

    2016-03-01

    Cryogenic propellants such as liquid hydrogen (LH2) and liquid oxygen (LO2) are a part of NASA's future space exploration plans due to their high specific impulse for rocket motors of upper stages. However, the low storage temperatures of LH2 and LO2 cause substantial boil-off losses for long duration missions. These losses can be eliminated by incorporating high performance cryocooler technology to intercept heat load to the propellant tanks and modulating the cryocooler temperature to control tank pressure. The technology being developed by NASA is the reverse turbo-Brayton cycle cryocooler and its integration to the propellant tank through a distributed cooling tubing network coupled to the tank wall. This configuration was recently tested at NASA Glenn Research Center in a vacuum chamber and cryoshroud that simulated the essential thermal aspects of low Earth orbit, its vacuum and temperature. This test series established that the active cooling system integrated with the propellant tank eliminated boil-off and robustly controlled tank pressure.

  2. Comparative study of heat transfer and pressure drop during flow boiling and flow condensation in minichannels

    Directory of Open Access Journals (Sweden)

    Mikielewicz Dariusz

    2014-09-01

    Full Text Available In the paper a method developed earlier by authors is applied to calculations of pressure drop and heat transfer coefficient for flow boiling and also flow condensation for some recent data collected from literature for such fluids as R404a, R600a, R290, R32,R134a, R1234yf and other. The modification of interface shear stresses between flow boiling and flow condensation in annular flow structure are considered through incorporation of the so called blowing parameter. The shear stress between vapor phase and liquid phase is generally a function of nonisothermal effects. The mechanism of modification of shear stresses at the vapor-liquid interface has been presented in detail. In case of annular flow it contributes to thickening and thinning of the liquid film, which corresponds to condensation and boiling respectively. There is also a different influence of heat flux on the modification of shear stress in the bubbly flow structure, where it affects bubble nucleation. In that case the effect of applied heat flux is considered. As a result a modified form of the two-phase flow multiplier is obtained, in which the nonadiabatic effect is clearly pronounced.

  3. Analysis of heat transfer under high heat flux nucleate boiling conditions

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y.; Dinh, N. [3145 Burlington Laboratories, Raleigh, NC (United States)

    2016-07-15

    Analysis was performed for a heater infrared thermometric imaging temperature data obtained from high heat flux pool boiling and liquid film boiling experiments BETA. With the OpenFOAM solver, heat flux distribution towards the coolant was obtained by solving transient heat conduction of heater substrate given the heater surface temperature data as boundary condition. The so-obtained heat flux data was used to validate them against the state-of-art wall boiling model developed by D. R. Shaver (2015) with the assumption of micro-layer hydrodynamics. Good agreement was found between the model prediction and data for conditions away from the critical heat flux (CHF). However, the data indicate a different heat transfer pattern under CHF, which is not captured by the current model. Experimental data strengthen the notion of burnout caused by the irreversible hot spot due to failure of rewetting. The observation forms a basis for a detailed modeling of micro-layer hydrodynamics under high heat flux.

  4. Families of quasi-pseudo-metrics generated by probabilistic quasi-pseudo-metric spaces

    Directory of Open Access Journals (Sweden)

    Mariusz T. Grabiec

    2008-03-01

    Full Text Available This paper contains a study of families of quasi-pseudo-metrics (the concept of a quasi-pseudo-metric was introduced by Wilson (1931 , Albert (1941 and Kelly (1963 generated by probabilistic quasi-pseudo-metric-spaces which are generalization of probabilistic metric space (PM-space shortly [2, 3, 4, 6]. The idea of PM-spaces was introduced by Menger (1942, 1951, Schweizer and Sklar (1983 and Serstnev (1965. Families of pseudo-metrics generated by PM-spaces and those generalizing PM-spaces have been described by Stevens (1968 and Nishiure (1970.

  5. Critical heat flux in flow boiling in microchannels

    CERN Document Server

    Saha, Sujoy Kumar

    2015-01-01

    This Brief concerns the important problem of critical heat flux in flow boiling in microchannels. A companion edition in the SpringerBrief Subseries on Thermal Engineering and Applied Science to “Heat Transfer and Pressure Drop in Flow Boiling in Microchannels,” by the same author team, this volume is idea for professionals, researchers, and graduate students concerned with electronic cooling.

  6. Direct Numerical Simulation and Visualization of Subcooled Pool Boiling

    Directory of Open Access Journals (Sweden)

    Tomoaki Kunugi

    2014-01-01

    Full Text Available A direct numerical simulation of the boiling phenomena is one of the promising approaches in order to clarify their heat transfer characteristics and discuss the mechanism. During these decades, many DNS procedures have been developed according to the recent high performance computers and computational technologies. In this paper, the state of the art of direct numerical simulation of the pool boiling phenomena during mostly two decades is briefly summarized at first, and then the nonempirical boiling and condensation model proposed by the authors is introduced into the MARS (MultiInterface Advection and Reconstruction Solver developed by the authors. On the other hand, in order to clarify the boiling bubble behaviors under the subcooled conditions, the subcooled pool boiling experiments are also performed by using a high speed and high spatial resolution camera with a highly magnified telescope. Resulting from the numerical simulations of the subcooled pool boiling phenomena, the numerical results obtained by the MARS are validated by being compared to the experimental ones and the existing analytical solutions. The numerical results regarding the time evolution of the boiling bubble departure process under the subcooled conditions show a very good agreement with the experimental results. In conclusion, it can be said that the proposed nonempirical boiling and condensation model combined with the MARS has been validated.

  7. A QSPR STUDY OF NORMAL BOILING POINT OF ORGANIC ...

    African Journals Online (AJOL)

    2013-12-31

    Dec 31, 2013 ... Keywords: QSPR; Model; Molecular descriptors; Normal Boiling point; multiple linear regression "Stepwise" . 1. INTRODUCTION. Being firstly and easily measured as a property of a compound, the normal boiling point (NBP) is an important property for the simulation of processes in chemical and petroleum ...

  8. Proximate, Functional and Anti-Nutritional Properties of Boiled Ukpo ...

    African Journals Online (AJOL)

    The oxalate, tannin, saponin, phenol and phytate contents decreased significantly (p .0.05) with increasing boiling time. The values at 60 minutes boiling time were 0.14%, 0.182%, 0.434%, 0.146% and 0.719% respectively. These results suggest that heat treatment improves the performance of the Ukpo flour in soup ...

  9. Effect of boiling on the physicochemical properties of Roselle seeds ...

    African Journals Online (AJOL)

    Effect of boiling on the physicochemical composition of Roselle seeds (Hibiscus sabdariffa) grown in Mali was shown. Proximate analysis indicated that boiled whole Roselle seeds (BWRS) are potential high protein source. Moreover, the results of lipid analysis indicated that the seeds were good source of unsaturated fatty ...

  10. Prospective Primary School Teachers' Perceptions on Boiling and Freezing

    Science.gov (United States)

    Senocak, Erdal

    2009-01-01

    The aim of this study was to investigate the perceptions of prospective primary school teachers on the physical state of water during the processes of boiling and freezing. There were three stages in the investigation: First, open-ended questions concerning the boiling and freezing of water were given to two groups of prospective primary school…

  11. Chemical composition and nutritional value of boiled Christmas ...

    African Journals Online (AJOL)

    A study was conducted to determine the chemical composition and the nutritive value of boiled Christmas bush (Alchornea cordifolia) for starter broiler chickens. Dried Christmas bush fruits (Capsules + seed) were boiled for 30 minutes, sundried and ground into meal. The meal was analyzed for proximate composition and ...

  12. Boiling treatment of ABS and PS plastics for flotation separation.

    Science.gov (United States)

    Wang, Chong-qing; Wang, Hui; Wu, Bao-xin; Liu, Qun

    2014-07-01

    A new physical method, namely boiling treatment, was developed to aid flotation separation of acrylonitrile-butadiene-styrene (ABS) and polystyrene (PS) plastics. Boiling treatment was shown to be effective in producing a hydrophilic surface on ABS plastic. Fourier Transform Infrared analysis was conducted to investigate the mechanism of boiling treatment of ABS. Surface rearrangement of polymer may be responsible for surface change of boiling treated ABS, and the selective influence of boiling treatment on the floatability of boiling treated plastics may be attributed to the difference in the molecular mobility of polymer chains. The effects of flotation time, frother concentration and particle size on flotation behavior of simple plastic were investigated. Based on flotation behavior of simple plastic, flotation separation of boiling treatment ABS and PS with different particle sizes was achieved efficiently. The purity of ABS and PS was up to 99.78% and 95.80%, respectively; the recovery of ABS and PS was up to 95.81% and 99.82%, respectively. Boiling treatment promotes the industrial application of plastics flotation and facilitates plastic recycling. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Hybrid modelling of a sugar boiling process

    CERN Document Server

    Lauret, Alfred Jean Philippe; Gatina, Jean Claude

    2012-01-01

    The first and maybe the most important step in designing a model-based predictive controller is to develop a model that is as accurate as possible and that is valid under a wide range of operating conditions. The sugar boiling process is a strongly nonlinear and nonstationary process. The main process nonlinearities are represented by the crystal growth rate. This paper addresses the development of the crystal growth rate model according to two approaches. The first approach is classical and consists of determining the parameters of the empirical expressions of the growth rate through the use of a nonlinear programming optimization technique. The second is a novel modeling strategy that combines an artificial neural network (ANN) as an approximator of the growth rate with prior knowledge represented by the mass balance of sucrose crystals. The first results show that the first type of model performs local fitting while the second offers a greater flexibility. The two models were developed with industrial data...

  14. Microbiological effectiveness of disinfecting water by boiling in rural Guatemala.

    Science.gov (United States)

    Rosa, Ghislaine; Miller, Laura; Clasen, Thomas

    2010-03-01

    Boiling is the most common means of treating water in the home and the benchmark against which alternative point-of-use water treatment options must be compared. In a 5-week study in rural Guatemala among 45 households who claimed they always or almost always boiled their drinking water, boiling was associated with a 86.2% reduction in geometric mean thermotolerant coliforms (TTC) (N = 206, P water, 71.2% of stored water samples from self-reported boilers met the World Health Organization guidelines for safe drinking water (0 TTC/100 mL), and 10.7% fell within the commonly accepted low-risk category of (1-10 TTC/100 mL). As actually practiced in the study community, boiling significantly improved the microbiological quality of drinking water, though boiled and stored drinking water is not always free of fecal contaminations.

  15. Boiling in porous media; Ebullition en milieux poreux

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-11

    This conference day of the French society of thermal engineers was devoted to the analysis of heat transfers and fluid flows during boiling phenomena in porous media. This book of proceedings comprises 8 communications entitled: `boiling in porous medium: effect of natural convection in the liquid zone`; `numerical modeling of boiling in porous media using a `dual-fluid` approach: asymmetrical characteristic of the phenomenon`; `boiling during fluid flow in an induction heated porous column`; `cooling of corium fragment beds during a severe accident. State of the art and the SILFIDE experimental project`; `state of knowledge about the cooling of a particulates bed during a reactor accident`; `mass transfer analysis inside a concrete slab during fire resistance tests`; `heat transfers and boiling in porous media. Experimental analysis and modeling`; `concrete in accidental situation - influence of boundary conditions (thermal, hydric) - case studies`. (J.S.)

  16. Pool boiling enhancement through contact line augmentation

    Science.gov (United States)

    Raghupathi, P. A.; Kandlikar, S. G.

    2017-05-01

    In addition to transient conduction, microconvection, and microlayer evaporation, contact line region heat transfer has been identified as an important mode of heat transfer during boiling. In this work, we demonstrate that generating additional contact line regions within the base of a nucleating bubble leads to critical heat flux (CHF) enhancement. The creation of a liquid meniscus adjacent to 10-20 μm deep microgrooves in the bubble base area was responsible for the generation of the additional contact line regions. The depth of the microgrooves was determined such that a sufficient reservoir of liquid is present in the meniscus to sustain evaporation in the contact line region throughout the bubble cycle. The effective contact line length at the base of the bubble was seen to be a good indicator of the CHF (wetted area) over the surface. The microgroove geometry played a significant role in influencing the bubble dynamics and bubble departure diameter during boiling. It was seen that the bubbles were able to bridge and grow over the shallow microgrooves of 10-20 μm depth and generate additional contact line regions but were pinned and constrained within the grooves in the case of the microgrooves deeper than 100 μm. For shallow grooves, narrow grooves resulted in smaller bubbles, which in turn reduced the contact line length. The findings of this work could be used to design heat transfer surfaces that significantly enhance the contact line region contribution and CHF by placing shallow enhancement features on the surface of the heater.

  17. Enceladus Plumes: A Boiling Liquid Model

    Science.gov (United States)

    Nakajima, Miki; Ingersoll, A. P.

    2012-10-01

    Following the discovery of H2O vapor and particle plumes from the tiger stripes at the south pole of Enceladus (Porco et al., 2006), observational and theoretical studies have been conducted to understand the plume mechanism (e.g., Schmidt et al., 2008; Kieffer et al., 2009; Ingersoll and Pankine, 2010). Although the “Ice Chamber Model”, which assumes that ice sublimation under the stripes causes the plumes, has successfully explained the plume mass flux (e.g., Nimmo et al., 2007; Ingersoll and Pankine, 2010), it cannot explain the high salinity in the plume (Postberg et al., 2009). Ice particles condensing from a vapor are relatively salt free, but ice particles derived from a salty liquid can have high salinity. Therefore we have investigated the “Boiling Liquid Model”, which assumes that liquid H2O under the stripes causes the plumes. With conservation of mass, momentum and energy, we built a simple atmospheric model that includes controlled boiling and gas-ice wall interaction. We first assumed that the heat radiated to space comes entirely from the heat generated by condensation of the gas onto the ice wall. We varied the width (0.1-1 m) and the height (5-4000 m) of the crack as parameters. We find that the escaping vapor flux can be relatively close to the observed value (250±100 kg/s, Hansen et al., 2006, 2008) but the radiated heat flux is only 1 GW, which is much less than the observed value (15.8 GW, Howett et al., 2011). Other models (Nimmo et al., 2007; Abramov and Spencer, 2009) also have the same difficulty accounting for the observed value. We then investigated the additional heat radiated by the particles after they come out of the crack. We built a simple model to estimate the size distributions of these condensed ice particles and their radiative properties.

  18. The initiation of boiling during pressure transients. [water boiling on metal surfaces

    Science.gov (United States)

    Weisman, J.; Bussell, G.; Jashnani, I. L.; Hsieh, T.

    1973-01-01

    The initiation of boiling of water on metal surfaces during pressure transients has been investigated. The data were obtained by a new technique in which light beam fluctuations and a pressure signal were simultaneously recorded on a dual beam oscilloscope. The results obtained agreed with those obtained using high speed photography. It was found that, for water temperatures between 90-150 C, the wall superheat required to initiate boiling during a rapid pressure transient was significantly higher than required when the pressure was slowly reduced. This result is explained by assuming that a finite time is necessary for vapor to fill the cavity at which the bubble originates. Experimental measurements of this time are in reasonably good agreement with calculations based on the proposed theory. The theory includes a new procedure for estimating the coefficient of vaporization.

  19. Multi-scale Control and Enhancement of Reactor Boiling Heat Flux by Reagents and Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Manglik, R M; Athavale, A; Kalaikadal, D S; Deodhar, A; Verma, U

    2011-09-02

    The phenomenological characterization of the use of non-invasive and passive techniques to enhance the boiling heat transfer in water has been carried out in this extended study. It provides fundamental enhanced heat transfer data for nucleate boiling and discusses the associated physics with the aim of addressing future and next-generation reactor thermal-hydraulic management. It essentially addresses the hypothesis that in phase-change processes during boiling, the primary mechanisms can be related to the liquid-vapor interfacial tension and surface wetting at the solidliquid interface. These interfacial characteristics can be significantly altered and decoupled by introducing small quantities of additives in water, such as surface-active polymers, surfactants, and nanoparticles. The changes are fundamentally caused at a molecular-scale by the relative bulk molecular dynamics and adsorption-desorption of the additive at the liquid-vapor interface, and its physisorption and electrokinetics at the liquid-solid interface. At the micro-scale, the transient transport mechanisms at the solid-liquid-vapor interface during nucleation and bubblegrowth can be attributed to thin-film spreading, surface-micro-cavity activation, and micro-layer evaporation. Furthermore at the macro-scale, the heat transport is in turn governed by the bubble growth and distribution, macro-layer heat transfer, bubble dynamics (bubble coalescence, collapse, break-up, and translation), and liquid rheology. Some of these behaviors and processes are measured and characterized in this study, the outcomes of which advance the concomitant fundamental physics, as well as provide insights for developing control strategies for the molecular-scale manipulation of interfacial tension and surface wetting in boiling by means of polymeric reagents, surfactants, and other soluble surface-active additives.

  20. Cryogenic two-phase flow during chilldown: Flow transition and nucleate boiling heat transfer

    Science.gov (United States)

    Jackson, Jelliffe Kevin

    The recent interest in space exploration has placed a renewed focus on rocket propulsion technology. Cryogenic propellants are the preferred fuel for rocket propulsion since they are more energetic and environmentally friendly compared with other storable fuels. Voracious evaporation occurs while transferring these fluids through a pipeline that is initially in thermal equilibrium with the environment. This phenomenon is referred to as line chilldown. Large temperature differences, rapid transients, pressure fluctuations and the transition from the film boiling to the nucleate boiling regime characterize the chilldown process. Although the existence of the chilldown phenomenon has been known for decades, the process is not well understood. Attempts have been made to model the chilldown process; however the results have been fair at best. A major shortcoming of these models is the use of correlations that were developed for steady, non-cryogenic flows. The development of reliable correlations for cryogenic chilldown has been hindered by the lack of experimental data. An experimental facility was constructed that allows the flow structure, the temperature history and the pressure history to be recorded during the line chilldown process. The temperature history is then utilized in conjunction with an inverse heat conduction procedure that was developed, which allows the unsteady heat transfer coefficient on the interior of the pipe wall to be extracted. This database is used to evaluate present predictive models and correlations for flow regime transition and nucleate boiling heat transfer. It is found that by calibrating the transition between the stratified-wavy and the intermittent/annular regimes of the Taitel and Dukler flow regime map, satisfactory predictions are obtained. It is also found that by utilizing a simple model that includes the effect of flow structure and incorporating the enhancement provided by the local heat flux, significant improvement in the

  1. Effect of local phenomena on subcooled boiling oscillations in natural circulation boiling loop

    Energy Technology Data Exchange (ETDEWEB)

    Karmakar, Arnab [Birla Institute of Technology, Mesra, Jharkhand 835215 (India); Dey, Runa [Indian School of Mines, Dhanbad, Jharkhand 826004 (India); Paruya, Swapan, E-mail: swapanparuya@gmail.com [National Institute of Technology, Durgapur, West Bengal 713209 (India)

    2016-12-15

    Highlights: • The estimations of bubble frequency and oscillation of local void fraction α in a natural circulation boiling loop. • The effect of inlet subcooling on the bubble frequency and the oscillations of local α and local pressure. • Effect of local dynamic phenomena on the system oscillations in terms of loop flow rate. • The α-oscillations due to the presence of large bubbles trigger the high-amplitude system-oscillations with a time delay. - Abstract: In this paper, the authors report the estimations of bubble frequency and oscillation of local void fraction and their role in subcooled boiling oscillations in a low-pressure natural circulation boiling loop. The estimations primarily rely on the measurements of impedance using inductance L–capacitance C–resistance R (LCR) meter. The bubble frequencies determined from the impedance signals and the images are comparable. The effect of inlet subcooling on the bubble frequency and the oscillation of local void fraction has been studied and found to be remarkable. Based on the comparison of the oscillations of local void fraction, local pressure and loop flow rate, the effect of local dynamic phenomena on the system oscillations clearly demonstrates that the oscillations of void fraction trigger high-amplitude flow oscillations with a delay between the oscillations of void fraction and loop flow rate.

  2. Pseudo-template synthesis of gold nanoparticles based on polyhydrosilanes

    Energy Technology Data Exchange (ETDEWEB)

    Sacarescu, Liviu, E-mail: livius@icmpp.ro [Petru Poni Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda 41A, Iasi 700487 (Romania); Simionescu, Mihaela; Sacarescu, Gabriela [Petru Poni Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda 41A, Iasi 700487 (Romania)

    2011-02-01

    Highly stable colloidal gold nanoparticles are obtained in a pseudo-template system using a specific polyhydrosilane copolymeric structure. This process takes place in situ by microwaves activation of the polymer solution in a non-polar solvent followed by stirring with solid HAuCl{sub 4} in natural light. The experimental procedure is very simple and the resulted colloidal gold solution is indefinitely stable. The specific surface plasmon resonance absorption band of the gold nanoparticles is strongly red shifted and is strictly related to their size. AFM correlated with DLS analysis showed flattened round shaped colloidal polymer-gold nanoparticles with large diameters. SEM-EDX combined analysis reveals that the polysilane-gold nanoparticles show a natural tendency to auto-assemble in close packed structures which form large areas over the polymer film surface.

  3. Pseudo-capacitor device for aqueous electrolytes

    Science.gov (United States)

    Prakash, J.; Thackeray, M.M.; Dees, D.W.; Vissers, D.R.; Myles, K.M.

    1998-11-24

    A pseudo-capacitor having a high energy storage capacity develops a double layer capacitance as well as a Faradaic or battery-like redox reaction, also referred to as pseudo-capacitance. The Faradaic reaction gives rise to a capacitance much greater than that of the typical ruthenate oxide ultracapacitor which develops only charge separation-based double layer capacitance. The capacitor employs a lead and/or bismuth/ruthenate and/or iridium system having the formula A{sub 2}[B{sub 2{minus}x}Pb{sub x}]O{sub 7{minus}y}, where A=Pb, Bi, and B=Ru, Ir, and Opseudo-capacitance, affords high energy/power density in the pseudo-capacitor. The amount of expensive ruthenate and iridium can be substantially reduced in the pseudo-capacitor by increasing the lead content while improving energy storage capacity. 8 figs.

  4. Aerodynamics of the pseudo-glottis.

    Science.gov (United States)

    Kotby, M N; Hegazi, M A; Kamal, I; Gamal El Dien, N; Nassar, J

    2009-01-01

    The aim of this work is to study the hitherto unclear aerodynamic parameters of the pseudo-glottis following total laryngectomy. These parameters include airflow rate, sub-pseudo-glottic pressure (SubPsG), efficiency and resistance, as well as sound pressure level (SPL). Eighteen male patients who have undergone total laryngectomy, with an age range from 54 to 72 years, were investigated in this study. All tested patients were fluent esophageal 'voice' speakers utilizing tracheo-esophageal prosthesis. The airflow rate, SubPsG and SPL were measured. The results showed that the mean value of the airflow rate was 53 ml/s, the SubPsG pressure was 13 cm H(2)O, while the SPL was 66 dB. The normative data obtained from the true glottis in healthy age-matched subjects are 89 ml/s, 7.9 cm H(2)O and 70 dB, respectively. Other aerodynamic indices were calculated and compared to the data obtained from the true glottis. Such a comparison of the pseudo-glottic aerodynamic data to the data of the true glottis gives an insight into the mechanism of action of the pseudo-glottis. The data obtained suggests possible clinical applications in pseudo-voice training. Copyright 2009 S. Karger AG, Basel.

  5. SEARCHING FOR LOW WEIGHT PSEUDO-CODEWORDS

    Energy Technology Data Exchange (ETDEWEB)

    CHERTKOV, MICHAEL [Los Alamos National Laboratory; STEPANOV, MIKHAIL [Los Alamos National Laboratory

    2007-01-23

    Belief Propagation (BP) and Linear Programming (LP) decodings of LDPC codes are discussed. The authors summarize results of instanton/pseudo-codeword approach developed for analysis of the error-floor domain of the codes. Instantons are special, code and decoding specific, configurations of the channel noise contributing most to the Frame-Error-Rate (FER). Instantons are decoded into pseudo-codewords. Instanton/pseudo-codeword with the lowest weight describes the largest Signal-to-Noise-Ratio (SNR) asymptotic of FER, while the whole spectra of the low weight instantons is descriptive of the FER vs. SNR profile in the extended error-floor domain. First, they describe a general optimization method that allows to find the instantons for any coding/decoding. Second, they introduce LP-specific pseudo-codeword search algorithm that allows efficient calculations of the pseudo-codeword spectra. Finally, they discuss results of combined BP/LP error-floor exploration experiments for two mode codes.

  6. Enhanced flow boiling in microchannels through integrating multiple micro-nozzles and reentry microcavities

    Science.gov (United States)

    Li, Wenming; Qu, Xiaopeng; Alam, Tamanna; Yang, Fanghao; Chang, Wei; Khan, Jamil; Li, Chen

    2017-01-01

    In a microchannel system, a higher mass velocity can lead to enhanced flow boiling performances, but at a cost of two-phase pressure drop. It is highly desirable to achieve a high heat transfer rate and critical heat flux (CHF) exceeding 1 kW/cm2 without elevating the pressure drop, particularly, at a reduced mass velocity. In this study, we developed a microchannel configuration that enables more efficient utilization of the coolant through integrating multiple microscale nozzles connected to auxiliary channels as well as microscale reentry cavities on sidewalls of main microchannels. We achieved a CHF of 1016 W/cm2 with a 50% less mass velocity, i.e., 680 kg/m2s, compared to the two-nozzle configuration developed in our previous studies. Two primary enhancement mechanisms are: (a) the enhanced global liquid supply by four evenly distributed micronozzles, particularly near the outlet region and (b) the effective management of local dryout by the capillary flow-induced sustainable thin liquid film resulting from an array of microscale cavities. A significantly improved heat transfer coefficient of 131 kW/m2 K at a mass velocity of 680 kg/m2s is attributed to the enhanced nucleate boiling, the established capillary/thin film evaporation, and the induced advection from the present microchannel configuration. All these significant enhancements have been achieved with a ˜55% lower two-phase pressure drop.

  7. Pseudo exchange bias due to rotational anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Ehrmann, A., E-mail: andrea.ehrmann@fh-bielefeld.de [Faculty of Engineering and Mathematics, Bielefeld University of Applied Sciences, 33619 Bielefeld (Germany); Komraus, S.; Blachowicz, T.; Domino, K. [Institute of Physics – Center for Science and Education, Silesian University of Technology, 44-100 Gliwice (Poland); Nees, M.K.; Jakobs, P.J.; Leiste, H. [Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen (Germany); Mathes, M.; Schaarschmidt, M. [ACCESS e. V., 57072 Aachen (Germany)

    2016-08-15

    Ferromagnetic nanostructure arrays with particle dimensions between 160 nm and 400 nm were created by electron-beam lithography. The permalloy structures consist of rectangular-shaped walls around a square open space. While measuring their magnetic properties using the Magneto-Optical Kerr Effect (MOKE), in some angular regions an exchange bias (EB) seemed to appear. This paper gives an overview of possible reasons for this “pseudo exchange bias” and shows experimentally and by means of micromagnetic simulations that this effect can be attributed to unintentionally measuring minor loops. - Highlights: • Pseudo exchange bias can be found in square Py nanorings of different dimensions. • Pseudo exchange bias stems from unintentionally measuring minor loops. • New approach in explaining “real” exchange bias effect in coupled FM/AFM systems. • Theoretical base to explain other measurements of a rotational anisotropy.

  8. Analysis of flow boiling of ammonia and R-114 in a matrix heat exchanger

    Science.gov (United States)

    Panchal, C. B.

    1989-05-01

    An analysis is carried out for flow boiling in a vertical matrix aluminum heat exchanger. The prediction model, developed for thin film evaporation in a previous study, is extended to include heat transfer in the slug-flow regime that exists at low mass qualities. Appropriate criteria is used to switch from slug-flow to thin-film annular-flow analysis. The two-phase-flow convective heat transfer enhancement for the slug-flow is correlated with inclusion of fluid Reynolds and Prandtl numbers in addition to commonly used Martinelli parameter. This approach reflects transient nature of heat transfer in the slug-flow regime. The thin-film annular-flow analysis developed in the previous study is refined with inclusion of a reliable two-phase friction factor correlation. The experimentally measured pressure drop is used to validate the friction factor correlation. The resulting prediction method is used to predict exit mass qualities for ammonia and R-114. The experimental analysis includes flow boiling of ammonia and R-114 in a vertical brazed-aluminum matrix heat exchanger. The test unit has straight perforated fins on the fluid side and extruded rectangular channels on the single-phase (water) heating-media side. Only two parameters are adjusted to validate the analytical prediction method, the constant in the friction factor correlation, and the constant in the slug-flow heat transfer correlation. The results show that the combination of slug-flow and thin-film annular-flow model gives better prediction of the overall performance of the matrix heat exchanger than a single model applied for the whole range of mass qualities.

  9. A pseudo-matched filter for chaos

    OpenAIRE

    Cohen, Seth D.; Gauthier, Daniel J.

    2012-01-01

    A matched filter maximizes the signal-to-noise ratio of a signal. In the recent work of Corron et al. [Chaos 20, 023123 (2010)], a matched filter is derived for the chaotic waveforms produced by a piecewise-linear system. Motivated by these results, we describe a pseudo-matched filter, which removes noise from the same chaotic signal. It consists of a notch filter followed by a first-order, low-pass filter. We compare quantitatively the matched filter's performance to that of our pseudo-match...

  10. A case of Pseudo-Bartter syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ik; Choi, Bo Whan; Lee, Yul; Chung, Soo Young [College of Medicine, Hallym University, Seoul (Korea, Republic of)

    1994-10-15

    Pseudo-Bartter Syndrome is a rare medical disease of the kidney characterized by normal blood pressure, hypokalemic metabolic alkalosis, hyperreninemia and hyperaldosteronism with drug history of diuretics. We report US, CT and MRI findings of a patients with clinically proved Pseudo-Bartter syndrome. The patient was a 37 year old woman with a history of long term ingestion of the diuretics(furosemide) for 20 years. Renal US revealed hyperechoic renal medulla at both kidneys. The resistive index(RI), calculated from the duplex doppler waveform is 0.61. Unenhanced CT revealed faint high attenuation along the medulla. T1-weighted MRI revealed indistinct corticomedullary differentiation.

  11. Self-Sustaining Thorium Boiling Water Reactors

    Directory of Open Access Journals (Sweden)

    Ehud Greenspan

    2012-10-01

    Full Text Available A thorium-fueled water-cooled reactor core design approach that features a radially uniform composition of fuel rods in stationary fuel assembly and is fuel-self-sustaining is described. This core design concept is similar to the Reduced moderation Boiling Water Reactor (RBWR proposed by Hitachi to fit within an ABWR pressure vessel, with the following exceptions: use of thorium instead of depleted uranium for the fertile fuel; elimination of the internal blanket; and elimination of absorbers from the axial reflectors, while increasing the length of the fissile zone. The preliminary analysis indicates that it is feasible to design such cores to be fuel-self-sustaining and to have a comfortably low peak linear heat generation rate when operating at the nominal ABWR power level of nearly 4000 MWth. However, the void reactivity feedback tends to be too negative, making it difficult to have sufficient shutdown reactivity margin at cold zero power condition. An addition of a small amount of plutonium from LWR used nuclear fuel was found effective in reducing the magnitude of the negative void reactivity effect and enables attaining adequate shutdown reactivity margin; it also flattens the axial power distribution. The resulting design concept offers an efficient incineration of the LWR generated plutonium in addition to effective utilization of thorium. Additional R&D is required in order to arrive at a reliable practical and safe design.

  12. Visualization of boiling flow structure in a natural circulation boiling loop

    Energy Technology Data Exchange (ETDEWEB)

    Karmakar, Arnab; Paruya, Swapan, E-mail: swapanparuya@gmail.com

    2015-04-15

    Highlights: • Vapor–liquid jet flows in natural circulation boiling loop. • Flow patterns and their transitions during geysering instability in the loop. • Evaluation of the efficiency of the needle probe in detecting the vapor–liquid and boiling flow structure. - Abstract: The present study reports vapor–liquid jet flows, flow patterns and their transitions during geysering instability in a natural circulation boiling loop under varied inlet subcooling ΔT{sub sub} (30–50 °C) and heater power Q (4–5 kW). Video imaging, voltage measurement using impedance needle probe, measurement of local pressure and loop flow rate have been carried out in this study. Power spectra of the voltage, the pressure and the flow rate reveal that at a high ΔT{sub sub} the jet flows have long period (21.36–86.95 s) and they are very irregular with a number of harmonics. The period decreases and becomes regular with a decrease of ΔT{sub sub}. The periods of the jet flows at ΔT{sub sub} = 30–50 °C and Q = 4 kW are in close agreement with those obtained from the video imaging. The probe was found to be more efficient than the pressure sensor in detecting the jet flows within an uncertainty of 9.5% and in detecting a variety of bubble classes. Both the imaging and the probe consistently identify the bubbly flow/vapor-mushrooms transition or the bubbly flow/slug flow transition on decreasing ΔT{sub sub} or on increasing Q.

  13. Ground Water Rule - Boil Water Advisory - Public Notification Template

    Science.gov (United States)

    The Ground Water Rule - Boil Water Advisory - Public Notification Template can be use to issue a Tier 1 Public Notification when it has been determined that source ground water is contaminated with E. Coli bacteria.

  14. Nanoparticle Deposition During Cu-Water Nanofluid Pool Boiling

    Science.gov (United States)

    Doretti, L.; Longo, G. A.; Mancin, S.; Righetti, G.; Weibel, J. A.

    2017-11-01

    The present research activity aims to rigorously investigate nanofluid pool boiling in order to definitively assess this as a technique for controlled nanoparticle coating of surfaces, which can enhance the nucleate boiling performance. This paper presents preliminary nanoparticle deposition results obtained during Cu-water (0.13 wt%) nanofluid pool boiling on a smooth copper surface. The tests were run in an experimental setup designed expressly to study water and nanofluid pool boiling. The square test sample block (27.2 mm × 27.2 mm) is equipped with a rake of four calibrated T-type thermocouples each located in a 13.6-mm deep holes drilled every 5 mm from 1 mm below the top surface. The imposed heat flux and wall superheat can be estimated from measurement of the temperature gradient along the four thermocouples. The samples are characterized by scanning electron microscopy (SEM) to analyse the morphological characteristics of the obtained thin, Cu nanoparticle coating.

  15. Effect Of Green Leaves And Germination And Boiling Treatments Of ...

    African Journals Online (AJOL)

    Trigonella foenum graecum L.) were commercial, Giza 2 and Giza 30 and fenugreek green leaves and raw, boiled and germinated commercial sweet lupin seeds (lupinus termis forssk L.) were analyzed for its chemical composition, alkaloids and ...

  16. Boiling local heat transfer enhancement in minichannels using nanofluids

    Science.gov (United States)

    Chehade, Ali Ahmad; Gualous, Hasna Louahlia; Le Masson, Stephane; Fardoun, Farouk; Besq, Anthony

    2013-03-01

    This paper reports an experimental study on nanofluid convective boiling heat transfer in parallel rectangular minichannels of 800 μm hydraulic diameter. Experiments are conducted with pure water and silver nanoparticles suspended in water base fluid. Two small volume fractions of silver nanoparticles suspended in water are tested: 0.000237% and 0.000475%. The experimental results show that the local heat transfer coefficient, local heat flux, and local wall temperature are affected by silver nanoparticle concentration in water base fluid. In addition, different correlations established for boiling flow heat transfer in minichannels or macrochannels are evaluated. It is found that the correlation of Kandlikar and Balasubramanian is the closest to the water boiling heat transfer results. The boiling local heat transfer enhancement by adding silver nanoparticles in base fluid is not uniform along the channel flow. Better performances and highest effect of nanoparticle concentration on the heat transfer are obtained at the minichannels entrance.

  17. Performance and carcass characteristics of broilers fed boiled ...

    African Journals Online (AJOL)

    Performance and carcass characteristics of broilers fed boiled cowpea (Vigna unguiculata L Walp) and or black common bean (Phaseolus vulgaris) meal diets. HF Defang, A Teguia, J Awah-Ndukum, A Kenfack, F Ngoula, F Metuge ...

  18. Zero Boil Off System for Cryogen Storage Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This work proposes to develop a zero boil off (ZBO) dewar using a two-stage pulse-tube cooler together with two innovative, continuous-flow cooling loops and an...

  19. Boiling local heat transfer enhancement in minichannels using nanofluids

    Science.gov (United States)

    2013-01-01

    This paper reports an experimental study on nanofluid convective boiling heat transfer in parallel rectangular minichannels of 800 μm hydraulic diameter. Experiments are conducted with pure water and silver nanoparticles suspended in water base fluid. Two small volume fractions of silver nanoparticles suspended in water are tested: 0.000237% and 0.000475%. The experimental results show that the local heat transfer coefficient, local heat flux, and local wall temperature are affected by silver nanoparticle concentration in water base fluid. In addition, different correlations established for boiling flow heat transfer in minichannels or macrochannels are evaluated. It is found that the correlation of Kandlikar and Balasubramanian is the closest to the water boiling heat transfer results. The boiling local heat transfer enhancement by adding silver nanoparticles in base fluid is not uniform along the channel flow. Better performances and highest effect of nanoparticle concentration on the heat transfer are obtained at the minichannels entrance. PMID:23506445

  20. Some Properties of Weighted Pseudo almost Periodic Functions

    Directory of Open Access Journals (Sweden)

    Zhe-Ming Zheng

    2013-01-01

    Full Text Available Several interesting and new properties of weighted pseudo almost periodic functions are established. Firstly, we obtain an equivalent definition for weighted pseudo almost periodic functions, which shows a close relationship between asymptotically almost periodic functions and weighted pseudo almost periodic functions; secondly, we prove that the space of asymptotically almost periodic functions is always a proper subspace of the space of weighted pseudo almost periodic functions; thirdly, we show that under some cases, the space of weighted pseudo almost periodic functions equals the classical space of pseudo almost periodic functions.

  1. Laser-induced boiling of biological liquids in medical technologies

    Science.gov (United States)

    Chudnovskii, V. M.; Yusupov, V. I.; Dydykin, A. V.; Nevozhai, V. I.; Kisilev, A. Yu.; Zhukov, S. A.; Bagratashvili, V. N.

    2017-05-01

    Using optical and acoustic methods we study thermal and transport processes related to the boiling of biological liquids under the action of continuous-wave laser radiation having moderate power (1 - 10 W) in the near-IR range (0.97 - 1.94 μm). These processes are investigated in the course of a few particular clinical procedures aimed at the modification and removal of pathological tissues (veins, mammary gland cyst, Baker’s cyst) and tissue regeneration (intervertebral discs). In the proposed approach, the modification and destruction of biotissues are due to the fast delivery of heat by two-phase jet flows, formed in the course of liquid boiling, rather than the direct laser heating. This provides the high rate of heat delivery to the pathological biotissue, avoiding its overheating (the temperature higher than 100 °C) and undesired heating of adjacent tissues. Two main regimes of laser-induced boiling near the optical fibre tip were revealed, namely, the heterogeneous jet boiling (arising when the fibre with a blackened tip is used) and the homogeneous boiling (with the radiation absorbed in the liquid volume). Both studied regimes allow one to obtain high specific heat flows, and the domination of one of the boiling regimes is determined by the presence of absorbing coating on the fibre tip, the tissue type, as well as by its shape (e.g., the presence of channels or cavities in the tissue). It is established that the heterogeneous jet boiling at the fibre tip corresponds to the regime of superintensive bubble boiling.

  2. Pseudo--Normals for Signed Distance Computation

    DEFF Research Database (Denmark)

    Aanæs, Henrik; Bærentzen, Jakob Andreas

    2003-01-01

    undertake showing that the angle weighted pseudo--normal has an important property, namely that it allows us to discriminate between points that are inside and points that are outside the mesh. This result is used for proposing a simple and efficient algorithm for computing the signed distance field from...

  3. POPULATION DYNAMICS OF PSEUDO-NITZSCHIA SPECIES ...

    African Journals Online (AJOL)

    nb

    coastal waters of the Western Indian Ocean has been reported before (Bryceson ... Ocean. There is however no study, which has analyzed the seasonal distribution of. Pseudo-nitzschia species along the. Tanzanian coastal waters as well as factors regulating such ... cleaned plastic vials and immediately kept cool on ice for ...

  4. A pseudo-matched filter for chaos.

    Science.gov (United States)

    Cohen, Seth D; Gauthier, Daniel J

    2012-09-01

    A matched filter maximizes the signal-to-noise ratio of a signal. In the recent work of Corron et al. [Chaos 20, 023123 (2010)], a matched filter is derived for the chaotic waveforms produced by a piecewise-linear system. This system produces a readily available binary symbolic dynamics that can be used to perform correlations in the presence of large amounts of noise using the matched filter. Motivated by these results, we describe a pseudo-matched filter, which operates similarly to the original matched filter. It consists of a notch filter followed by a first-order, low-pass filter. We compare quantitatively the matched filter's performance to that of our pseudo-matched filter using correlation functions. On average, the pseudo-matched filter performs with a correlation signal-to-noise ratio that is 2.0 dB below that of the matched filter. Our pseudo-matched filter, though somewhat inferior in comparison to the matched filter, is easily realizable at high speed (>1 GHz) for potential radar applications.

  5. Pseudo-Canonical Formulae are Classical

    Directory of Open Access Journals (Sweden)

    Caminati Marco B.

    2015-02-01

    Full Text Available An original result about Hilbert Positive Propositional Calculus introduced in [11] is proven. That is, it is shown that the pseudo-canonical formulae of that calculus (and hence also the canonical ones, see [17] are a subset of the classical tautologies.

  6. Pseudo-observations in survival analysis

    DEFF Research Database (Denmark)

    Andersen, Per Kragh; Perme, Maja Pohar

    2010-01-01

    -state models, e.g. the competing risks cumulative incidence function. Graphical and numerical methods for assessing goodness-of-fit for hazard regression models and for the Fine-Gray model in competing risks studies based on pseudo-observations are also reviewed. Sensitivity to covariate-dependent censoring...... is studied. The methods are illustrated using a data set from bone marrow transplantation....

  7. Surface Structure Enhanced Microchannel Flow Boiling

    OpenAIRE

    Zhu, Yangying; Antao, Dion Savio; Chu, Kuang-Han; Chen, Siyu; Hendricks, Terry J.; Zhang, Tiejun; Wang, Evelyn N.

    2016-01-01

    We investigated the role of surface microstructures in two-phase microchannels on suppressing flow instabilities and enhancing heat transfer. We designed and fabricated microchannels with well-defined silicon micropillar arrays on the bottom heated microchannel wall to promote capillary flow for thin film evaporation while facilitating nucleation only from the sidewalls. Our experimental results show significantly reduced temperature and pressure drop fluctuation especially at high heat fluxe...

  8. Primary palpebral and orbital ossification in pseudo-pseudohypoparathyroidism

    DEFF Research Database (Denmark)

    Klauber, S.; Heegaard, S.; Prause, J.U.

    2002-01-01

    ophthalmology, Albright's heriditary osteodystrophy, ossification, pseudo-pseudohypoparathyroidism, pseodohypoparathyroidism, hypothyroidism, GNAS1 gene, history, eyelid, orbit......ophthalmology, Albright's heriditary osteodystrophy, ossification, pseudo-pseudohypoparathyroidism, pseodohypoparathyroidism, hypothyroidism, GNAS1 gene, history, eyelid, orbit...

  9. Wavefield extrapolation in pseudo-depth domain

    KAUST Repository

    Ma, Xuxin

    2012-01-01

    Extrapolating seismic waves in Cartesian coordinate is prone to uneven spatial sampling, because the seismic wavelength tends to grow with depth, as velocity increase. We transform the vertical depth axis to a pseudo one using a velocity weighted mapping, which can effectively mitigate this wavelength variation. We derive acoustic wave equations in this new domain based on the direct transformation of the Laplacian derivatives, which admits solutions that are more accurate and stable than those derived from the kinematic transformation. The anisotropic versions of these equations allow us to isolate the vertical velocity influence and reduce its impact on modeling and imaging. The major benefit of extrapolating wavefields in pseudo-depth space is its near uniform wavelength as opposed to the normally dramatic change of wavelength with the conventional approach. Time wavefield extrapolation on a complex velocity shows some of the features of this approach.

  10. Pseudo-differential operators and generalized functions

    CERN Document Server

    Toft, Joachim

    2015-01-01

    This book gathers peer-reviewed contributions representing modern trends in the theory of generalized functions and pseudo-differential operators. It is dedicated to Professor Michael Oberguggenberger (Innsbruck University, Austria) in honour of his 60th birthday. The topics covered were suggested by the ISAAC Group in Generalized Functions (GF) and the ISAAC Group in Pseudo-Differential Operators (IGPDO), which met at the 9th ISAAC congress in Krakow, Poland in August 2013. Topics include Columbeau algebras, ultra-distributions, partial differential equations, micro-local analysis, harmonic analysis, global analysis, geometry, quantization, mathematical physics, and time-frequency analysis. Featuring both essays and research articles, the book will be of great interest to graduate students and researchers working in analysis, PDE and mathematical physics, while also offering a valuable complement to the volumes on this topic previously published in the OT series.

  11. Inflation and pseudo-Goldstone Higgs boson

    DEFF Research Database (Denmark)

    Alanne, Tommi; Sannino, Francesco; Tenkanen, Tommi

    2017-01-01

    We consider inflation within a model framework where the Higgs boson arises as a pseudo-Goldstone boson associated with the breaking of a global symmetry at a scale significantly larger than the electroweak one. We show that in such a model the scalar self-couplings can be parametrically suppressed...... field. Our model therefore suggests that inflation and low energy particle phenomenology may be more entwined than assumed so far....

  12. Pseudo-Hermitian random matrix theory

    Science.gov (United States)

    Srivastava, S. C. L.; Jain, S. R.

    2013-02-01

    Complex extension of quantum mechanics and the discovery of pseudo-unitarily invariant random matrix theory has set the stage for a number of applications of these concepts in physics. We briefly review the basic ideas and present applications to problems in statistical mechanics where new results have become possible. We have found it important to mention the precise directions where advances could be made if further results become available.

  13. Pseudo-Hermitian random matrix theory

    OpenAIRE

    Srivastava, Shashi C. L.; Jain, S. R.

    2013-01-01

    Complex extension of quantum mechanics and the discovery of pseudo-unitarily invariant random matrix theory has set the stage for a number of applications of these concepts in physics. We briefly review the basic ideas and present applications to problems in statistical mechanics where new results have become possible. We have found it important to mention the precise directions where advances could be made if further results become available.

  14. Gravity and Heater Size Effects on Pool Boiling Heat Transfer

    Science.gov (United States)

    Kim, Jungho; Raj, Rishi

    2014-01-01

    The current work is based on observations of boiling heat transfer over a continuous range of gravity levels between 0g to 1.8g and varying heater sizes with a fluorinert as the test liquid (FC-72/n-perfluorohexane). Variable gravity pool boiling heat transfer measurements over a wide range of gravity levels were made during parabolic flight campaigns as well as onboard the International Space Station. For large heaters and-or higher gravity conditions, buoyancy dominated boiling and heat transfer results were heater size independent. The power law coefficient for gravity in the heat transfer equation was found to be a function of wall temperature under these conditions. Under low gravity conditions and-or for smaller heaters, surface tension forces dominated and heat transfer results were heater size dependent. A pool boiling regime map differentiating buoyancy and surface tension dominated regimes was developed along with a unified framework that allowed for scaling of pool boiling over a wide range of gravity levels and heater sizes. The scaling laws developed in this study are expected to allow performance quantification of phase change based technologies under variable gravity environments eventually leading to their implementation in space based applications.

  15. Enhanced boiling heat transfer in horizontal test bundles

    Energy Technology Data Exchange (ETDEWEB)

    Trewin, R.R.; Jensen, M.K.; Bergles, A.E.

    1994-08-01

    Two-phase flow boiling from bundles of horizontal tubes with smooth and enhanced surfaces has been investigated. Experiments were conducted in pure refrigerant R-113, pure R-11, and mixtures of R-11 and R-113 of approximately 25, 50, and 75% of R-113 by mass. Tests were conducted in two staggered tube bundles consisting of fifteen rows and five columns laid out in equilateral triangular arrays with pitch-to-diameter ratios of 1.17 and 1.5. The enhanced surfaces tested included a knurled surface (Wolverine`s Turbo-B) and a porous surface (Linde`s High Flux). Pool boiling tests were conducted for each surface so that reference values of the heat transfer coefficient could be obtained. Boiling heat transfer experiments in the tube bundles were conducted at pressures of 2 and 6 bar, heat flux values from 5 to 80 kW/m{sup 2}s, and qualities from 0% to 80%, Values of the heat transfer coefficients for the enhanced surfaces were significantly larger than for the smooth tubes and were comparable to the values obtained in pool boiling. It was found that the performance of the enhanced tubes could be predicted using the pool boiling results. The degradation in the smooth tube heat transfer coefficients obtained in fluid mixtures was found to depend on the difference between the molar concentration in the liquid and vapor.

  16. Analyzing and Post-modelling the High Speed Images of a Wavy Laser Induced Boiling Front

    Science.gov (United States)

    Matti, R. S.; Kaplan, A. F. H.

    The boiling front in laser materials processing like remote fusion cutting, keyhole welding or drilling can nowadays be recorded by high speed imaging. It was recently observed that bright waves flow down the front. Several complex physical mechanisms are associated with a stable laser-induced boiling front, like beam absorption, shadowing, heating, ablation pressure, fluid flow, etc. The evidence of dynamic phenomena from high speed imaging is closely linked to these phenomena. As a first step, the directly visible phenomena were classified and analyzed. This has led to the insight that the appearance of steady flow of the bright front peaks is a composition of many short flashing events of 20-50 μs duration, though composing a rather constant melt film flow downwards. Five geometrical front shapes of bright and dark domains were categorized, for example long inclined dark valleys. In addition, the special top and bottom regions of the front are distinguished. As a second step, a new method of post-modelling based on the greyscale variation of the images was applied, to approximately reconstruct the topology of the wavy front and subsequently to calculate the absorption across the front. Despite certain simplifications this kind of analysis provides a variety of additional information, including statistical analysis. In particular, the model could show the sensitivity of front waves to the formation of shadow domains and the robustness of fiber lasers to keep most of an irradiated steel surface in an absorptivity window between 35 to 43%.

  17. Wavefield Extrapolation in Pseudo-depth Domain

    KAUST Repository

    Ma, Xuxin

    2011-12-11

    Wave-equation based seismic migration and inversion tools are widely used by the energy industry to explore hydrocarbon and mineral resources. By design, most of these techniques simulate wave propagation in a space domain with the vertical axis being depth measured from the surface. Vertical depth is popular because it is a straightforward mapping of the subsurface space. It is, however, not computationally cost-effective because the wavelength changes with local elastic wave velocity, which in general increases with depth in the Earth. As a result, the sampling per wavelength also increases with depth. To avoid spatial aliasing in deep fast media, the seismic wave is oversampled in shallow slow media and therefore increase the total computation cost. This issue is effectively tackled by using the vertical time axis instead of vertical depth. This is because in a vertical time representation, the "wavelength" is essentially time period for vertical rays. This thesis extends the vertical time axis to the pseudo-depth axis, which features distance unit while preserving the properties of the vertical time representation. To explore the potentials of doing wave-equation based imaging in the pseudo-depth domain, a Partial Differential Equation (PDE) is derived to describe acoustic wave in this new domain. This new PDE is inherently anisotropic because the use of a constant vertical velocity to convert between depth and vertical time. Such anisotropy results in lower reflection coefficients compared with conventional space domain modeling results. This feature is helpful to suppress the low wavenumber artifacts in reverse-time migration images, which are caused by the widely used cross-correlation imaging condition. This thesis illustrates modeling acoustic waves in both conventional space domain and pseudo-depth domain. The numerical tool used to model acoustic waves is built based on the lowrank approximation of Fourier integral operators. To investigate the potential

  18. Boiling heat transfer on fins – experimental and numerical procedure

    Directory of Open Access Journals (Sweden)

    Orzechowski T.

    2014-03-01

    Full Text Available The paper presents the research methodology, the test facility and the results of investigations into non-isothermal surfaces in water boiling at atmospheric pressure, together with a discussion of errors. The investigations were conducted for two aluminium samples with technically smooth surfaces and thickness of 4 mm and 10 mm, respectively. For the sample of lower thickness, on the basis of the surface temperature distribution measured with an infrared camera, the local heat flux and the heat transfer coefficient were determined and shown in the form of a boiling curve. For the thicker sample, for which 1-D model cannot be used, numerical calculations were conducted. They resulted in obtaining the values of the local heat flux on the surface the invisible to the infrared, camera i.e. on the side on which the boiling of the medium proceeds.

  19. Changes of enthalpy slope in subcooled flow boiling

    Energy Technology Data Exchange (ETDEWEB)

    Collado, Francisco J.; Monne, Carlos [Universidad de Zaragoza-CPS, Departamento de Ingenieria Mecanica-Motores Termicos, Zaragoza (Spain); Pascau, Antonio [Universidad de Zaragoza-CPS, Departamento de Ciencia de los Materiales y Fluidos-Mecanica de Fluidos, Zaragoza (Spain)

    2006-03-01

    Void fraction data in subcooled flow boiling of water at low pressure measured by General Electric in the 1960s are analyzed following the classical model of Griffith et al. (in Proceedings of ASME-AIChE heat transfer conference, 58-HT-19, 1958). In addition, a new proposal for analyzing one-dimensional steady flow boiling is used. This is based on the physical fact that if the two phases have different velocities, they cannot cover the same distance - the control volume length - in the same time. So a slight modification of the heat balance is suggested, i.e., the explicit inclusion of the vapor-liquid velocity ratio or slip ratio as scaling time factor between the phases, which is successfully checked against the data. Finally, the prediction of void fraction using correlations of the net rate of change of vapor enthalpy in the fully developed regime of subcooled flow boiling is explored. (orig.)

  20. Study on Boiling Heat Transfer Phenomenon in Micro-channels

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Namgyun [Inha Technical College, Incheon (Korea, Republic of)

    2017-09-15

    Recently, efficient heat dissipation has become necessary because of the miniaturization of devices, and research on boiling on micro-channels has attracted attention. However, in the case of micro-channels, the friction coefficient and heat transfer characteristics are different from those in macro-channels. This leads to large errors in the micro scale results, when compared to correlations derived from the macro scale. In addition, due to the complexity of the mechanism, the boiling phenomenon in micro-channels cannot be approached only by experimental and theoretical methods. Therefore, numerical methods should be utilized as well, to supplement these methods. However, most numerical studies have been conducted on macro-channels. In this study, we applied the lattice Boltzmann method, proposed as an alternative numerical tool to simulate the boiling phenomenon in the micro-channel, and predicted the bubble growth process in the channel.

  1. Boiling heat transfer of refrigerant R-21 in upward flow in plate-fin heat exchanger

    Science.gov (United States)

    Kuznetsov, V. V.; Shamirzaev, A. S.

    2015-11-01

    The article presents the results of experimental investigation of boiling heat transfer of refrigerant R-21 in upward flow in a vertical plate-fin heat exchanger with transverse size of the channels that is smaller than the capillary constant. The heat transfer coefficients obtained in ranges of small mass velocities and low heat fluxes, which are typical of the industry, have been poorly studied yet. The characteristic patterns of the upward liquid-vapor flow in the heat exchanger channels and the regions of their existence are detected. The obtained data show a weak dependence of heat transfer coefficient on equilibrium vapor quality, mass flow rate, and heat flux density and do not correspond to calculations by the known heat transfer models. A possible reason for this behavior is a decisive influence of evaporation of thin liquid films on the heat transfer at low heat flux.

  2. Defluoridation of drinking water by boiling with brushite and calcite.

    Science.gov (United States)

    Larsen, M J; Pearce, E I F

    2002-01-01

    Existing methods for defluoridating drinking water involve expensive high technology or are slow, inefficient and/or unhygienic. A new method is now suggested, encompassing brushite and calcite suspension followed by boiling. Our aim was to examine the efficiency of the method and the chemical reactions involved. Brushite, 0.3-0.5 g, and an equal weight of calcite were suspended in 1 litre water containing 5-20 ppm fluoride. The suspensions were boiled in an electric kettle, left to cool and the calcium salts to sediment. Solution ion concentrations were determined and sediments were examined by X-ray diffraction. In distilled water initially containing 5, 10 and 20 ppm fluoride the concentration was reduced to 0.06, 0.4 and 5.9 ppm, respectively. Using Aarhus tap water which contained 2.6 mmol/l calcium the final concentrations were 1.2, 2.5 and 7.7 ppm, respectively, and runs without calcite gave results similar to those with calcite. Without boiling the fluoride concentration remained unaltered, as did the brushite and calcite salts, despite occasional agitation by hand. All solutions were supersaturated with respect to fluorapatite and hydroxyapatite and close to saturation with respect to brushite. Boiling produced well-crystallised apatite and traces of calcite, while boiling of brushite alone left a poorly crystallised apatite. We conclude that boiling a brushite/calcite suspension rapidly converts the two salts to apatite which incorporates fluoride if present in solution, and that this process may be exploited to defluoridate drinking water. Copyright 2002 S. Karger AG, Basel

  3. Novel Si ion implantation technique for improving the radiation hardness of SOI pseudo-MOS transistor

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanwei [Key Laboratory of Low Dimensional Materials and Application Technology, Xiangtan University, Ministry of Education, Xiangtan, Hunan 411105 (China); State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Huang, Huixiang; Bi, Dawei [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Tang, Minghua, E-mail: mhtang@xtu.edu.cn [Key Laboratory of Low Dimensional Materials and Application Technology, Xiangtan University, Ministry of Education, Xiangtan, Hunan 411105 (China); Zhang, Zhengxuan [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)

    2014-01-15

    The pseudo-MOS transistor is a quick and effective technique for characterizing the electrical properties of silicon-on-insulator (SOI) wafer. We investigated the total ionizing dose (TID) response of pseudo-MOS transistors fabricated on SOI wafers hardened by single or multiple step Si ion implantation. It is demonstrated that the two Si ion implantation methods can both improve the radiation hardness of SOI wafers owing to the generation of deep electron traps in the buried oxide (BOX). However, the lattice damage of top silicon film caused by the single step implantation compared with the multiple degenerates the electrical properties of transistors, especially for the sub-threshold swing. The high resolution transmission electron microscopy (HRTEM) was used to observe the lattice quality.

  4. Hysteresis of boiling for different tunnel-pore surfaces

    Directory of Open Access Journals (Sweden)

    Pastuszko Robert

    2015-01-01

    Full Text Available Analysis of boiling hysteresis on structured surfaces covered with perforated foil is proposed. Hysteresis is an adverse phenomenon, preventing high heat flux systems from thermal stabilization, characterized by a boiling curve variation at an increase and decrease of heat flux density. Experimental data were discussed for three kinds of enhanced surfaces: tunnel structures (TS, narrow tunnel structures (NTS and mini-fins covered with the copper wire net (NTS-L. The experiments were carried out with water, R-123 and FC-72 at atmospheric pressure. A detailed analysis of the measurement results identified several cases of type I, II and III for TS, NTS and NTS-L surfaces.

  5. Heat Transfer in Boiling Dilute Emulsion with Strong Buoyancy

    Science.gov (United States)

    Freeburg, Eric Thomas

    Little attention has been given to the boiling of emulsions compared to that of boiling in pure liquids. The advantages of using emulsions as a heat transfer agent were first discovered in the 1970s and several interesting features have since been studied by few researchers. Early research focuses primarily on pool and flow boiling and looks to determine a mechanism by which the boiling process occurs. This thesis looks at the boiling of dilute emulsions in fluids with strong buoyant forces. The boiling of dilute emulsions presents many favorable characteristics that make it an ideal agent for heat transfer. High heat flux electronics, such as those seen in avionics equipment, produce high heat fluxes of 100 W/cm2 or more, but must be maintained at low temperatures. So far, research on single phase convection and flow boiling in small diameter channels have yet to provide an adequate solution. Emulsions allow the engineer to tailor the solution to the specific problem. The fluid can be customized to retain the high thermal conductivity and specific heat capacity of the continuous phase while enhancing the heat transfer coefficient through boiling of the dispersed phase component. Heat transfer experiments were carried out with FC-72 in water emulsions. FC-72 has a saturation temperature of 56 °C, far below that of water. The parameters were varied as follows: 0% ≤ epsilon ≤ 1% and 1.82 x 1012 ≤ RaH ≤ 4.42 x 1012. Surface temperatures along the heated surface reached temperature that were 20 °C in excess of the dispersed phase saturation temperature. An increase of ˜20% was seen in the average Nusselt numbers at the highest Rayleigh numbers. Holography was used to obtain images of individual and multiple FC-72 droplets in the boundary layer next to the heated surface. The droplet diameters ranged from 0.5 mm to 1.3 mm. The Magnus effect was observed when larger individual droplets were injected into the boundary layer, causing the droplets to be pushed

  6. On Boiling of Crude Oil under Elevated Pressure

    CERN Document Server

    Pimenova, Anastasiya V

    2015-01-01

    We construct a thermodynamic model for theoretical calculation of the boiling process of multicomponent mixtures of hydrocarbons (e.g., crude oil). The model governs kinetics of the mixture composition in the course of the distillation process along with the boiling temperature increase. The model heavily relies on the theory of dilute solutions of gases in liquids. Importantly, our results are applicable for modelling the process under elevated pressure (while the empiric models for oil cracking are not scalable to the case of extreme pressure), such as in an oil field heated by lava intrusions.

  7. On Boiling of Crude Oil under Elevated Pressure

    Science.gov (United States)

    Pimenova, Anastasiya V.; Goldobin, Denis S.

    2016-02-01

    We construct a thermodynamic model for theoretical calculation of the boiling process of multicomponent mixtures of hydrocarbons (e.g., crude oil). The model governs kinetics of the mixture composition in the course of the distillation process along with the boiling temperature increase. The model heavily relies on the theory of dilute solutions of gases in liquids. Importantly, our results are applicable for modelling the process under elevated pressure (while the empiric models for oil cracking are not scalable to the case of extreme pressure), such as in an oil field heated by lava intrusions.

  8. Motivation and results of a long-term research on pool boiling heat transfer in low gravity

    Energy Technology Data Exchange (ETDEWEB)

    Di Marco, P.; Grassi, W. Lothar [Low gravity and Thermal Advanced Research Laboratory, Dipartimento di Energetica ' ' L. Poggi' ' , Universita di Pisa (Italy)

    2002-06-01

    This paper summarises the main results of a long-term research, begun more than ten years ago, about the influence of gravity and electric fields on heat transfer. After a somehow detailed analysis of the impact of heat transfer on modern society and of the motivation of low gravity research on this subject, the authors describe their own research work on the effects of gravitational and electric forces on single-phase convection and pool boiling. This research has the twofold aim to investigate the basic mechanisms of convective heat transfer, without the masking effect of gravity, and to identify methods to make free convection possible also in the absence of buoyancy, for space applications. It has been experimentally shown that the application of an external electric field generally enhances the heat exchange between a heated wire and a liquid pool. The single-phase heat transfer coefficient is improved, the nucleate boiling region is extended to higher heat fluxes, by increasing the critical heat flux, CHF, as well as the heat transfer rate in film boiling is augmented. The convective heat exchange is an increasing function of gravity, therefore heat transfer generally deteriorates in low gravity. The application of a sufficiently intense electric field restores the same value of heat transfer coefficient and critical heat flux measured on earth, thus demonstrating the progressive overwhelming of the electrical force on the buoyancy one. (authors)

  9. Pseudo-Hermitian random matrix theory

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, S.C.L. [RIBFG, Variable Energy Cyclotron Centre, 1/AF Bidhan nagar, Kolkata-700 064 (India); Jain, S.R. [NPD, Bhabha Atomic Research Centre, Mumbai-400 085 (India)

    2013-02-15

    Complex extension of quantum mechanics and the discovery of pseudo-unitarily invariant random matrix theory has set the stage for a number of applications of these concepts in physics. We briefly review the basic ideas and present applications to problems in statistical mechanics where new results have become possible. We have found it important to mention the precise directions where advances could be made if further results become available. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Bladder rupture causing pseudo acute renal failure

    Directory of Open Access Journals (Sweden)

    Luciana Andrea Avena Smeili

    2011-09-01

    Full Text Available Bladder rupture is a rare condition associated with significant morbidityand mortality. It is classified into traumatic, nontraumatic or idiopathic andspontaneous. The nonspecific initial clinical presentation is followed bydiscomfort in the lower abdomen, oliguria, hematuria and ascitis. Laboratoryabnormalities simulate the picture of acute renal failure and occurs by amechanism called auto reverse dialysis, with absorption of excreta throughthe peritoneal membrane. The authors describe a case of bladder rupturein morphologically and functionally normal urinary bladder associated withalcohol intake in young healthy man, manifested by abdominal discomfort,pseudo renal failure and massive ascitis. The diagnosis was made by anabdominal multidetector computed tomography confirmed by the finding of7 cm laceration at laparotomy.

  11. Pseudo ventricular tachycardia: a case report.

    LENUS (Irish Health Repository)

    Riaz, A

    2012-02-01

    BACKGROUND: Dramatic artifacts of pseudo flutter have been reported in the past secondary to various factors including tremor (Handwerker and Raptopoulos in N Engl J Med 356:503, 2007) and dialysis machines (Kostis et al. in J Electrocardiol 40(4):316-318, 2007). METHODS: We present this unusual case where the artifact, produced by tremor, was so pronounced to be misdiagnosed and treated as ventricular tachycardia. CONCLUSION: This case highlights the importance of correlating ECG findings with history and clinical examination and of using 12 lead ECGs for rhythm interpretation especially to confirm consistence of arrhythmias in all leads.

  12. Acid-base equilibria of multilayered pseudo-polyelectrolytes

    Science.gov (United States)

    Mateo, Ayeisca E.; Priefer, Ronny

    2015-11-01

    The use of weak polyelectrolytes in multilayer polymer systems provides a means of altering the physicochemical properties of these thin films. Previously, we have examined the limits of the polyanions by incorporating the pseudo-polyelectrolytes (pPE's), poly(4-vinylphenol) (PVPh) and poly[5-(2-trifluoromethyl-1,1,1-trifluoro-2-hydroxypropyl)-2-norbornene] (PNBHFA). These pPE's, although being polyacids, should have pKa values in the basic versus acidic pH range. In order to determine the pKa(app) value of these polymers, once multilayered onto Snowtex silica particles with the weak polyelectrolyte, poly(allylamine hydrochloride) (PAH), we employed zeta potential. PVPh demonstrated pKa(app) values ranging from 10.55 to 11.08 which varied based upon assembly pH conditions as well as layer number. PAH yielded pKa(app) values ranging between 9.81 and 10.99 when multilayered with PVPh and 9.91-11.04 when partnered with PNBHFA. However, from our study it would appear that PNBHFA does not interact with PAH electrostatically, but rather via H-bonding, and therefore should actually not be classified as a pPE.

  13. (0 0 2-oriented growth and morphologies of ZnO thin films prepared by sol-gel method

    Directory of Open Access Journals (Sweden)

    Guo Dongyun

    2016-09-01

    Full Text Available Zinc acetate was used as a starting material to prepare Zn-solutions from solvents and ligands with different boiling temperature. The ZnO thin films were prepared on Si(1 0 0 substrates by spin-coating method. The effect of baking temperature and boiling temperature of the solvents and ligands on their morphologies and orientation was investigated. The solvents and ligands with high boiling temperature were favorable for relaxation of mechanical stress to form the smooth ZnO thin films. As the solvents and ligands with low boiling temperature were used to prepare Zn-solutions, the prepared ZnO thin films showed (0 0 2 preferred orientation. As n-propanol, 2-methoxyethanol, 2-(methylaminoethanol and monoethanolamine were used to prepare Zn-solutions, highly (0 0 2-oriented ZnO thin films were formed by adjusting the baking temperature.

  14. Effect of Boiling on the Cytotoxic and Antioxidant Properties of ...

    African Journals Online (AJOL)

    Purpose: To evaluate the effect of boiling on in vitro bioactivities potency of Balanites aegyptiaca L. Delile (desert date) aqueous extract, a juice used traditionally for cooking ready-to-eat millet flour paste. Methods: Desert date fruits (1.5 kg) were soaked in water (1:2, fruit: water) for 24 h and sieved. The extract was divided ...

  15. Investigation Status of Heat Exchange while Boiling Hydrocarbon Fuel

    Directory of Open Access Journals (Sweden)

    D. S. Obukhov

    2006-01-01

    Full Text Available The paper contains analysis of heat exchange investigations while boiling hydrocarbon fuel. The obtained data are within the limits of the S.S. Kutateladze dependence proposed in 1939. Heat exchange at non-stationary heat release has not been investigated. The data for hydrocarbon fuel with respect to critical density of heat flow are not available even for stationary conditions.

  16. Steam turbines with a low-boiling working agent

    OpenAIRE

    Morozov, N.; Karasev, V.

    2010-01-01

    The subject of the article is the assembly of a steam-generator plant with a natural working agent. A method of calculation for steam turbines with a low-boiling working agent is offered, which accounts for the correlation between the adiabatic curve indication, pressure and temperature in the overheated vapor area.

  17. Electrochemical study of aluminum corrosion in boiling high purity water

    Science.gov (United States)

    Draley, J. E.; Legault, R. A.

    1969-01-01

    Electrochemical study of aluminum corrosion in boiling high-purity water includes an equation relating current and electrochemical potential derived on the basis of a physical model of the corrosion process. The work involved an examination of the cathodic polarization behavior of 1100 aluminum during aqueous oxidation.

  18. Effects of Ixeris Chinensis (Thunb.) Nakai boiling water extract on ...

    African Journals Online (AJOL)

    Background: Hepatitis B virus (HBV) infection and hepatocellular carcinoma are major diseases that affect the Taiwanese population. Therefore, the development of an alternative herbal medicine that can effectively treat these diseases is a research target. In this study, we tested Ixeris Chinensis (Thunb.) Nakai boiling ...

  19. Making Sense of Boiling Points and Melting Points

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 6. Making Sense of Boiling Points and Melting Points. S Prahlada Rao Shravan Sunkada. General Article Volume 12 Issue 6 June 2007 pp 43-57. Fulltext. Click here to view fulltext PDF. Permanent link:

  20. Making Sense of Boiling Points and Melting Points

    Indian Academy of Sciences (India)

    tion and dispersion forces, collectively called non-covalent inter- actions. They are attractive at distances of ~1 nm. These interac- tions have energy comparable to thermal energy, k n. T and hence are disrupted easily. They affect the bulk properties like melting point, boiling point, viscosity, surface tension, chromatographic.

  1. Heat transfer research on enhanced heating surfaces in pool boiling

    Science.gov (United States)

    Kalawa, Wojciech; Wójcik, Tadeusz M.; Piasecka, Magdalena

    The paper focuses on the analysis of the enhanced surfaces in such applications as boiling heat transfer. The testing measurement module with enhanced heating surfaces was used for pool boiling research. Pool boiling experiments were conducted with distilled water at atmospheric pressure in the vessel using an enhanced sample as the bottom heating surface. The samples are soldered to a copper heating block of the round cross-section .They were placed: in the fluid (saturation temperature measurement), under the sample for temperature determination. A vessel made of four flat glass panes was used for visualization. The heated surfaces in contact with the fluid differed in roughness were smooth or enhanced. This paper analyzes the effects of the microstructured heated surface on the heat transfer coefficient. The results are presented as relationships between the heat transfer coefficient and the heat flux and as boiling curves. The experimental data obtained for the two types of enhanced heated surfaces was compared with the results recorded for the smooth heated surface. The highest local values of the heat transfer coefficient were reported for the enhanced surfaces.

  2. EPA Statement on Flint Water Main Break, Boil Water Order

    Science.gov (United States)

    FLINT, MICH. -- The U.S. Environmental Protection Agency is working closely with the City of Flint and Michigan Department of Environmental Quality on the recent water main break and boil order. After the water transmission line broke on Feb. 9, EPA coordi

  3. Effects of Fermentation, Boiling and Roasting on Some ...

    African Journals Online (AJOL)

    The effects of processing methods such as fermentation, boiling and roasting on some micronutrients and antinutrient composition of jackfruit seed flour were evaluated. The mineral, vitamin and antinutrient composition of raw and processed jackfruit seed flours were determined using standard methods. Iron, calcium and ...

  4. Glycaemic Index Of Boiled Cocoyam And Stew | Alegbejo | Sahel ...

    African Journals Online (AJOL)

    Cocoyam can be processed in several ways. It contains digestible starch, protein and other valuable nutrients. Consumption of cocoyam is very high all over Nigeria. This study was undertaken to determine the glycaemic response of diabetic and healthy subjects to equal amounts of carbohydrate in the form of boiled ...

  5. How long does it take to boil an egg? Revisited

    Energy Technology Data Exchange (ETDEWEB)

    Buay, D [Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1, Nanyang Walk, Singapore 637616 (Singapore); Foong, S K [Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1, Nanyang Walk, Singapore 637616 (Singapore); Kiang, D [Department of Physics, Chinese University of Hong Kong, Shatin, New Territories, Hong Kong (China); Kuppan, L [Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1, Nanyang Walk, Singapore 637616 (Singapore); Centre for Research in Pedagogy and Practice, National Institute of Education, Nanyang Technological University, 1, Nanyang Walk, Singapore 637616 (Singapore); Liew, V H [Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1, Nanyang Walk, Singapore 637616 (Singapore)

    2006-01-01

    How long does it take to boil an egg? Theoretical prediction, based on a simple adaptation of the solution to the exact thermal diffusion equation for a sphere, is consistent with experiments. The experimental data are also used to estimate an average value for the thermal diffusivity of an egg.

  6. Effect of Different Soaking Time and Boiling on the Proximate ...

    African Journals Online (AJOL)

    The effect of soaking time on the proximate composition and functional properties of sprouted sesame seed flour were investigated. Sesame seed samples were cleaned and pretreated by soaking in clean water for 8, 10, 12, 14 and 16 h. One batch was sprouted for 36 h and another portion was sprouted and then boiled ...

  7. Nucleate pool boiling heat transfer in aqueous surfactant solutions

    Science.gov (United States)

    Wasekar, Vivek Mahadeorao

    Saturated, nucleate pool boiling in aqueous surfactant solutions is investigated experimentally. Also, the role of Marangoni convection, driven both by temperature and surfactant concentration gradients at the vapor-liquid interface of a nucleating bubble is computationally explored. Experimental measurements of dynamic and equilibrium sigma using the maximum bubble pressure method indicate dynamic sigma to be higher than the corresponding equilibrium value, both at room and elevated temperatures. Also, nonionic surfactants (Triton X-100, Triton X-305) show larger sigma depression than anionic surfactants (SDS, SLES), and a normalized representation of their dynamic adsorption isotherms is shown to be helpful in generalizing the surfactant effectiveness to reduce surface tension. The dynamic sigma has a primary role in the modification of bubble dynamics and associated heat transfer, and is dictated by the adsorption kinetics of the surfactant molecules at boiling temperatures. In general, an enhancement in heat transfer is observed, which is characterized by an early incipience and an optimum boiling performance at or around the critical micelle concentration of the surfactant. The optimum performances, typically in the fully developed boiling regime ( q''w > 100 kW/m2), show a reverse trend with respect to surfactant molecular weights M, i.e., higher molecular weight additives promote lower enhancement. Normalized boiling performance using the respective solution's dynamic sigma correlates heat transfer coefficient by M-0.5 for anionics and M 0 for nonionics. This has been shown to be brought about by the surfactant concentration and its interfacial activity in a concentration sublayer around the growing vapor bubble, which governs the bubble growth behavior through the mechanism of dynamic sigma. The ionic nature of the surfactant influences the thickness and molecular makeup of the enveloping sublayer, thereby affecting the bubble dynamics and boiling heat

  8. 77 FR 3009 - Knowledge and Abilities Catalog for Nuclear Power Plant Operators: Advanced Boiling Water Reactors

    Science.gov (United States)

    2012-01-20

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Knowledge and Abilities Catalog for Nuclear Power Plant Operators: Advanced Boiling Water Reactors..., ``Knowledge and Abilities Catalog for Nuclear Power Plant Operators: Advanced Boiling Water Reactors.'' DATES...

  9. 76 FR 14437 - Economic Simplified Boiling Water Reactor Standard Design: GE Hitachi Nuclear Energy; Issuance of...

    Science.gov (United States)

    2011-03-16

    ... From the Federal Register Online via the Government Publishing Office ] NUCLEAR REGULATORY COMMISSION Economic Simplified Boiling Water Reactor Standard Design: GE Hitachi Nuclear Energy; Issuance of... GE Hitachi Nuclear Energy (GEH) for the economic simplified boiling water reactor (ESBWR) standard...

  10. Modeling acid-gas generation from boiling chloride brines

    Directory of Open Access Journals (Sweden)

    Sonnenthal Eric

    2009-11-01

    Full Text Available Abstract Background This study investigates the generation of HCl and other acid gases from boiling calcium chloride dominated waters at atmospheric pressure, primarily using numerical modeling. The main focus of this investigation relates to the long-term geologic disposal of nuclear waste at Yucca Mountain, Nevada, where pore waters around waste-emplacement tunnels are expected to undergo boiling and evaporative concentration as a result of the heat released by spent nuclear fuel. Processes that are modeled include boiling of highly concentrated solutions, gas transport, and gas condensation accompanied by the dissociation of acid gases, causing low-pH condensate. Results Simple calculations are first carried out to evaluate condensate pH as a function of HCl gas fugacity and condensed water fraction for a vapor equilibrated with saturated calcium chloride brine at 50-150°C and 1 bar. The distillation of a calcium-chloride-dominated brine is then simulated with a reactive transport model using a brine composition representative of partially evaporated calcium-rich pore waters at Yucca Mountain. Results show a significant increase in boiling temperature from evaporative concentration, as well as low pH in condensates, particularly for dynamic systems where partial condensation takes place, which result in enrichment of HCl in condensates. These results are in qualitative agreement with experimental data from other studies. Conclusion The combination of reactive transport with multicomponent brine chemistry to study evaporation, boiling, and the potential for acid gas generation at the proposed Yucca Mountain repository is seen as an improvement relative to previously applied simpler batch evaporation models. This approach allows the evaluation of thermal, hydrological, and chemical (THC processes in a coupled manner, and modeling of settings much more relevant to actual field conditions than the distillation experiment considered. The actual

  11. Numerical Investigation of Microgravity Tank Pressure Rise Due to Boiling

    Science.gov (United States)

    Hylton, Sonya; Ibrahim, Mounir; Kartuzova, Olga; Kassemi, Mohammad

    2015-01-01

    The ability to control self-pressurization in cryogenic storage tanks is essential for NASAs long-term space exploration missions. Predictions of the tank pressure rise in Space are needed in order to inform the microgravity design and optimization process. Due to the fact that natural convection is very weak in microgravity, heat leaks into the tank can create superheated regions in the liquid. The superheated regions can instigate microgravity boiling, giving rise to pressure spikes during self-pressurization. In this work, a CFD model is developed to predict the magnitude and duration of the microgravity pressure spikes. The model uses the Schrage equation to calculate the mass transfer, with a different accommodation coefficient for evaporation at the interface, condensation at the interface, and boiling in the bulk liquid. The implicit VOF model was used to account for the moving interface, with bounded second order time discretization. Validation of the models predictions was carried out using microgravity data from the Tank Pressure Control Experiment, which flew aboard the Space Shuttle Mission STS-52. Although this experiment was meant to study pressurization and pressure control, it underwent boiling during several tests. The pressure rise predicted by the CFD model compared well with the experimental data. The ZBOT microgravity experiment is scheduled to fly on February 2016 aboard the ISS. The CFD model was also used to perform simulations for setting parametric limits for the Zero-Boil-Off Tank (ZBOT) Experiments Test Matrix in an attempt to avoid boiling in the majority of the test runs that are aimed to study pressure increase rates during self-pressurization. *Supported in part by NASA ISS Physical Sciences Research Program, NASA HQ, USA

  12. Bubble and boundary layer behaviour in subcooled flow boiling

    Energy Technology Data Exchange (ETDEWEB)

    Maurus, Reinhold; Sattelmayer, Thomas [Lehrstuhl fuer Thermodynamik, Technische Universitaet Muenchen, 85747 Garching (Germany)

    2006-03-15

    Subcooled flow boiling is a commonly applied technique for achieving efficient heat transfer. In the study, an experimental investigation in the nucleate boiling regime was performed for water circulating in a closed loop at atmospheric pressure. The horizontal orientated test-section consists of a rectangular channel with a one side heated copper strip and good optical access. Various optical observation techniques were applied to study the bubble behaviour and the characteristics of the fluid phase. The bubble behaviour was recorded by the high-speed cinematography and by a digital high resolution camera. Automated image processing and analysis algorithms developed by the authors were applied for a wide range of mass flow rates and heat fluxes in order to extract characteristic length and time scales of the bubbly layer during the boiling process. Using this methodology, the bubbles were automatically analysed and the bubble size, bubble lifetime, waiting time between two cycles were evaluated. Due to the huge number of observed bubbles a statistical analysis was performed and distribution functions were derived. Using a two-dimensional cross-correlation algorithm, the averaged axial phase boundary velocity profile could be extracted. In addition, the fluid phase velocity profile was characterised by means of the particle image velocimetry (PIV) for the single phase flow as well as under subcooled flow boiling conditions. The results indicate that the bubbles increase the flow resistance. The impact on the flow exceeds by far the bubbly region and it depends on the magnitude of the boiling activity. Finally, the ratio of the averaged phase boundary velocity and of the averaged fluid velocity was evaluated for the bubbly region. (authors)

  13. Modeling acid-gas generation from boiling chloride brines.

    Science.gov (United States)

    Zhang, Guoxiang; Spycher, Nicolas; Sonnenthal, Eric; Steefel, Carl

    2009-11-16

    This study investigates the generation of HCl and other acid gases from boiling calcium chloride dominated waters at atmospheric pressure, primarily using numerical modeling. The main focus of this investigation relates to the long-term geologic disposal of nuclear waste at Yucca Mountain, Nevada, where pore waters around waste-emplacement tunnels are expected to undergo boiling and evaporative concentration as a result of the heat released by spent nuclear fuel. Processes that are modeled include boiling of highly concentrated solutions, gas transport, and gas condensation accompanied by the dissociation of acid gases, causing low-pH condensate. Simple calculations are first carried out to evaluate condensate pH as a function of HCl gas fugacity and condensed water fraction for a vapor equilibrated with saturated calcium chloride brine at 50-150 degrees C and 1 bar. The distillation of a calcium-chloride-dominated brine is then simulated with a reactive transport model using a brine composition representative of partially evaporated calcium-rich pore waters at Yucca Mountain. Results show a significant increase in boiling temperature from evaporative concentration, as well as low pH in condensates, particularly for dynamic systems where partial condensation takes place, which result in enrichment of HCl in condensates. These results are in qualitative agreement with experimental data from other studies. The combination of reactive transport with multicomponent brine chemistry to study evaporation, boiling, and the potential for acid gas generation at the proposed Yucca Mountain repository is seen as an improvement relative to previously applied simpler batch evaporation models. This approach allows the evaluation of thermal, hydrological, and chemical (THC) processes in a coupled manner, and modeling of settings much more relevant to actual field conditions than the distillation experiment considered. The actual and modeled distillation experiments do not

  14. Some specific features of subcooled boiling heat transfer and crisis at extremely high heat flux densities

    Energy Technology Data Exchange (ETDEWEB)

    Gotovsky, M.A. [Polzunov Institute, Saint Petersburg (Russian Federation)

    2001-07-01

    Forced convection boiling is the process used widely in a lot of industry branches including NPP. Heat transfer intensity under forced convection boiling is considered in different way in dependence on conditions. One of main problems for the process considered is an influence of interaction between forced flow and boiling on heat transfer character. For saturated water case a transition from ''pure'' forced convection to nucleate boiling can be realized in smooth form. (author)

  15. Boiling heat transfer in narrow channels with offset strip fins: Application to electronic chipsets cooling

    OpenAIRE

    Pulvirenti, B.; Matalone, A.; Barucca, U.

    2010-01-01

    Abstract An experimental study on saturated flow boiling heat transfer of HFE-7100 in vertical rectangular channels with offset strip fins is presented. The experiments have been carried out at atmospheric pressure, over a wide range of vapour quality and heat fluxes up to 1.8?105 W/m2. The local boiling heat transfer coefficient has been obtained from experiments and analysed by means of Chen superposition method. Some correlations for convective boiling and nucleate boiling heat ...

  16. 77 FR 38339 - Dairyland Power Cooperative, La Crosse Boiling Water Reactor Exemption From Certain Security...

    Science.gov (United States)

    2012-06-27

    ... COMMISSION Dairyland Power Cooperative, La Crosse Boiling Water Reactor Exemption From Certain Security Requirements 1.0 Background The La Crosse Boiling Water Reactor (LACBWR) is owned and was operated by the..., which utilized a forced-circulation, direct-cycle boiling water reactor as its heat source. The plant is...

  17. 77 FR 36014 - Initial Test Program of Emergency Core Cooling Systems for Boiling-Water Reactors

    Science.gov (United States)

    2012-06-15

    ... COMMISSION Initial Test Program of Emergency Core Cooling Systems for Boiling-Water Reactors AGENCY: Nuclear...-1277, ``Initial Test Program of Emergency Core Cooling Systems for Boiling- Water Reactors.'' This... testing features of emergency core cooling systems (ECCSs) for boiling-water reactors (BWRs). DATES...

  18. Scaphoid pseudo-arthrosis: Frequency, pathogenesis and course

    Energy Technology Data Exchange (ETDEWEB)

    Schunk, K.; Teifke, A.; Benning, R.; Dahm, M.; Thelen, R.; Schild, H.

    1989-06-01

    Eighty-three scaphoid pseudo-arthroses were found amongst 1.104 scaphoid examinations. Sixtyseven were present at the first examination and 16 pseudo-arthroses developed amongst 252 scaphoid fractures. Men were affected predominantly, particularly in the 20 to 40-year old group. Fractures in the proximal third of the scaphoid and vertical oblique fractures had a particular tendency to pseudo-arthrosis formation. The operative treatment of choice is a Matti-Russe bone graft. Only one patient in seven with definite scaphoid pseudo-arthrosis showed firm fusion. (orig.).

  19. Annealing-free P3HT:PCBM-based organic solar cells via two halohydrocarbons additives with similar boiling points

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Xichang; Wang, Ting [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Yang, Ailing [Department of Physics, Ocean University of China, Qingdao 266100 (China); Yang, Chunpeng; Dou, Xiaowei; Chen, Weichao; Wang, Ning [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Yang, Renqiang, E-mail: yangrq@qibebt.ac.cn [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China)

    2014-02-15

    Highlights: • Two halohydrocarbons were selected as additives for polymer solar cells. • The additives can improve the photocurrent of photovoltaic devices. • Extensive characterization of the blends was done to explore the mechanism. -- Abstract: Efficient annealing-free inverted bulk heterojunction (BHJ) organic solar cells based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C{sub 61}-butyric acid methyl ester (PCBM) (1:1, w/w) have been obtained using two easily accessible halohydrocarbons (1,6-dibromohexane (DBH) and 1-bromodecane (BD)) with the same boiling points as solvent additives. The devices treated with 2.5 wt% additives removed the grain boundary of the large PCBM-rich phase, resulting in more-uniform film morphology on the nanoscale. The more-uniform film morphology greatly improved the short circuit current density of the devices. Finally, PCEs of the devices processed with DBH and BD reached 3.81% and 3.68%, respectively. Both additives with almost the same boiling points had a similar impact on device performance, despite of different chemical structures with different polarities and other physical properties.

  20. Strain-Induced Pseudo--Magnetic Fields in Graphene: MegaGauss in Nanobubbles

    Science.gov (United States)

    Levy, Niv

    2011-03-01

    Recent theoretical proposals suggest that strain can be used to modify graphene electronic states through the creation of a pseudo--magnetic field. This effect is unique to graphene because of its massless Dirac fermion-like band structure and particular lattice symmetry (C3v). Scanning tunneling microscopy shows that graphene grown on a platinum (111) surface forms nanobubbles, which are highly strained due to thermal expansion mismatch between the film and the substrate. We find that scanning tunneling spectroscopy measurements of these nanobubbles exhibit Landau levels that form in the presence of strain-induced pseudo--magnetic fields greater than 300 Tesla. This demonstration of enormous pseudo--magnetic fields opens the door to both the study of charge carriers in previously inaccessible high magnetic field regimes and deliberate mechanical control over electronic structure in graphene or so-called ``strain engineering''. In collaboration with S. A. Burke ,2 , K. L. Meaker 2 , M. Panlasigui 2 , A. Zettl 2,3 , F. Guinea 4 , A. H. Castro Neto 5 and M. F. Crommie 2,3 . 1. Present address: Department of Physics and Astronomy and Department of Chemistry, University of British Columbia, Vancouver, BC V6T 121, Canada. 2. Department of Physics, University of California, Berkeley, CA 94720, USA. 3. Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. 4. Instituto de Ciencia de Materiales de Madrid (CSIC), Madrid 28049, Spain. 5. Department of Physics, Boston University, Boston, MA 02215, USA.

  1. A New Theory of Nucleate Pool Boiling in Arbitrary Gravity

    Science.gov (United States)

    Buyevich, Y. A.; Webbon, Bruce W.

    1995-01-01

    Heat transfer rates specific to nucleate pool boiling under various conditions are determined by the dynamics of vapour bubbles that are originated and grow at nucleation sites of a superheated surface. A new dynamic theory of these bubbles has been recently developed on the basis of the thermodynamics of irreversible processes. In contrast to other existing models based on empirically postulated equations for bubble growth and motion, this theory does not contain unwarrantable assumptions, and both the equations are rigorously derived within the framework of a unified approach. The conclusions of the theory are drastically different from those of the conventional models. The bubbles are shown to detach themselves under combined action of buoyancy and a surface tension force that is proven to add to buoyancy in bubble detachment, but not the other way round as is commonly presumed. The theory ensures a sound understanding of a number of so far unexplained phenomena, such as effect caused by gravity level and surface tension on the bubble growth rate and dependence of the bubble characteristics at detachment on the liquid thermophysical parameters and relevant temperature differences. The theoretical predictions are shown to be in a satisfactory qualitative and quantitative agreement with observations. When being applied to heat transfer at nucleate pool boiling, this bubble dynamic theory offers an opportunity to considerably improve the main formulae that are generally used to correlate experimental findings and to design boiling heat removal in various industrial applications. Moreover, the theory makes possible to pose and study a great deal of new problems of essential impact in practice. Two such problems are considered in detail. One problem concerns the development of a principally novel physical model for the first crisis of boiling. This model allows for evaluating critical boiling heat fluxes under various conditions, and in particular at different

  2. Development of a mechanistic model for forced convection subcooled boiling

    Science.gov (United States)

    Shaver, Dillon R.

    The focus of this work is on the formulation, implementation, and testing of a mechanistic model of subcooled boiling. Subcooled boiling is the process of vapor generation on a heated wall when the bulk liquid temperature is still below saturation. This is part of a larger effort by the US DoE's CASL project to apply advanced computational tools to the simulation of light water reactors. To support this effort, the formulation of the dispersed field model is described and a complete model of interfacial forces is formulated. The model has been implemented in the NPHASE-CMFD computer code with a K-epsilon model of turbulence. The interfacial force models are built on extensive work by other authors, and include novel formulations of the turbulent dispersion and lift forces. The complete model of interfacial forces is compared to experiments for adiabatic bubbly flows, including both steady-state and unsteady conditions. The same model is then applied to a transient gas/liquid flow in a complex geometry of fuel channels in a sodium fast reactor. Building on the foundation of the interfacial force model, a mechanistic model of forced-convection subcooled boiling is proposed. This model uses the heat flux partitioning concept and accounts for condensation of bubbles attached to the wall. This allows the model to capture the enhanced heat transfer associated with boiling before the point of net generation of vapor, a phenomenon consistent with existing experimental observations. The model is compared to four different experiments encompassing flows of light water, heavy water, and R12 at different pressures, in cylindrical channels, an internally heated annulus, and a rectangular channel. The experimental data includes axial and radial profiles of both liquid temperature and vapor volume fraction, and the agreement can be considered quite good. The complete model is then applied to simulations of subcooled boiling in nuclear reactor subchannels consistent with the

  3. Pseudo-Observables in Higgs decays

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    In view of future high-statistics data, it is useful to define a framework for precise determinations of the properties of the Higgs particle valid in generic extensions of the Standard Model. For Higgs decays, this goal can be achieved with a limited set of "Pseudo-Observables" (PO). The PO provides a systematic generalization of the "kappa-framework" so far adopted by the LHC experiments and provide a useful bridge between data and theory predictions. I discuss how the PO are defined, with particular attention to the h->4f decays, and how they can be used to test various dynamical and symmetry hypotheses about the Higgs sector. The relation between PO and EFT couplings is also discussed.

  4. Flights in a pseudo-chaotic system.

    Science.gov (United States)

    Lowenstein, J H; Vivaldi, F

    2011-09-01

    We consider the problem of transport in a one-parameter family of piecewise rotations of the torus, for rotation number approaching 1∕4. This is a zero-entropy system which in this limit exhibits a divided phase space, with island chains immersed in a "pseudo-chaotic" region. We identify a novel mechanism for long-range transport, namely the adiabatic destruction of accelerator-mode islands. This process originates from the approximate translational invariance of the phase space and leads to long flights of linear motion, for a significant measure of initial conditions. We show that the asymptotic probability distribution of the flight lengths is determined by the geometric properties of a partition of the accelerator-mode island associated with the flight. We establish the existence of flights travelling distances of order O(1) in phase space. We provide evidence for the existence of a scattering process that connects flights travelling in opposite directions.

  5. Radon depletion in xenon boil-off gas

    Energy Technology Data Exchange (ETDEWEB)

    Bruenner, S.; Cichon, D.; Lindemann, S.; Undagoitia, T.M.; Simgen, H. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)

    2017-03-15

    An important background in detectors using liquid xenon for rare event searches arises from the decays of radon and its daughters. We report for the first time a reduction of {sup 222}Rn in the gas phase above a liquid xenon reservoir. We show a reduction factor of >or similar 4 for the {sup 222}Rn concentration in boil-off xenon gas compared to the radon enriched liquid phase. A semiconductor-based α-detector and miniaturized proportional counters are used to detect the radon. As the radon depletion in the boil-off gas is understood as a single-stage distillation process, this result establishes the suitability of cryogenic distillation to separate radon from xenon down to the 10{sup -15} mol/mol level. (orig.)

  6. Syngeneic AAV pseudo-vectors potentiates full vector transduction

    Science.gov (United States)

    An excessive amount of empty capsids are generated during regular AAV vector production process. These pseudo-vectors often remain in final vectors used for animal studies or clinical trials. The potential effects of these pseudo-vectors on AAV transduction have been a major concern. In the current ...

  7. Solutions of selected pseudo loop equations in water distribution ...

    African Journals Online (AJOL)

    This paper demonstrated the use of Microsoft Excel Solver (a computer package) in solving selected pseudo loop equations in pipe network analysis problems. Two pipe networks with pumps and overhead tanks were used to demonstrate the use of Microsoft Excel Solver in solving pseudo loops (open loops; networks with ...

  8. SELF-REGULATING BOILING-WATER NUCLEAR REACTORS

    Science.gov (United States)

    Ransohoff, J.A.; Plawchan, J.D.

    1960-08-16

    A boiling-water reactor was designed which comprises a pressure vessel containing a mass of water, a reactor core submerged within the water, a reflector tank disposed within the reactor, the reflector tank being open at the top to the interior of the pressure vessel, and a surge tank connected to the reflector tank. In operation the reflector level changes as a function of the pressure witoin the reactor so that the reactivity of the reactor is automatically controlled.

  9. Pool Boiling Enhancement of R-123 Using Perforated Plates

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nae-Hyun [Incheon Nat’l Univ., Incheon(Korea, Republic of)

    2016-05-15

    In this study, we investigate the pool boiling enhancement caused by perforated plates on top of a smooth surface. We conduct tests using R-123 at atmospheric pressure. It was shown that perforated plates significantly enhanced the pool boiling of the smooth surface. The reason may be attributed to the increased bubble contact area between the plates. The results showed that the enhancement ratio was dependent on the heat flux. At high heat flux, the enhancement ratio increased as the porosity increased. However, at low heat flux, the enhancement ratio decreased as the porosity increased. For the present investigation, the optimum configuration had a pore diameter of 2.0 mm, pore pitch of 2.5 mm×5.0 mm or 5.0 mm×5.0 mm, and a gap width of 0.5 mm, which yielded heat-transfer coefficients that are close to those of GEWA-T. The optimum porosity for R-123 was significantly larger than that of water or ethanol. The reason for this may be the large liquid-to-vapor density ratio along with the small latent heat of vaporization of R-123. The perforated plates yielded smaller boiling hysteresis compared with that of the smooth surface.

  10. Pseudo-populations a basic concept in statistical surveys

    CERN Document Server

    Quatember, Andreas

    2015-01-01

    This book emphasizes that artificial or pseudo-populations play an important role in statistical surveys from finite universes in two manners: firstly, the concept of pseudo-populations may substantially improve users’ understanding of various aspects in the sampling theory and survey methodology; an example of this scenario is the Horvitz-Thompson estimator. Secondly, statistical procedures exist in which pseudo-populations actually have to be generated. An example of such a scenario can be found in simulation studies in the field of survey sampling, where close-to-reality pseudo-populations are generated from known sample and population data to form the basis for the simulation process. The chapters focus on estimation methods, sampling techniques, nonresponse, questioning designs and statistical disclosure control.This book is a valuable reference in understanding the importance of the pseudo-population concept and applying it in teaching and research.

  11. PseudoBase++: an extension of PseudoBase for easy searching, formatting and visualization of pseudoknots.

    Science.gov (United States)

    Taufer, Michela; Licon, Abel; Araiza, Roberto; Mireles, David; van Batenburg, F H D; Gultyaev, Alexander P; Leung, Ming-Ying

    2009-01-01

    Pseudoknots have been recognized to be an important type of RNA secondary structures responsible for many biological functions. PseudoBase, a widely used database of pseudoknot secondary structures developed at Leiden University, contains over 250 records of pseudoknots obtained in the past 25 years through crystallography, NMR, mutational experiments and sequence comparisons. To promptly address the growing analysis requests of the researchers on RNA structures and bring together information from multiple sources across the Internet to a single platform, we designed and implemented PseudoBase++, an extension of PseudoBase for easy searching, formatting and visualization of pseudoknots. PseudoBase++ (http://pseudobaseplusplus.utep.edu) maps the PseudoBase dataset into a searchable relational database including additional functionalities such as pseudoknot type. PseudoBase++ links each pseudoknot in PseudoBase to the GenBank record of the corresponding nucleotide sequence and allows scientists to automatically visualize RNA secondary structures with PseudoViewer. It also includes the capabilities of fine-grained reference searching and collecting new pseudoknot information.

  12. The effects of geometric, flow, and boiling parameters on bubble growth and behavior in subcooled flow boiling

    Science.gov (United States)

    Samaroo, Randy

    Air bubble injection and subcooled flow boiling experiments have been performed to investigate the liquid flow field and bubble nucleation, growth, and departure, in part to contribute to the DOE Nuclear HUB project, Consortium for Advanced Simulation of Light Water Reactors (CASL). The main objective was to obtain quantitative data and compartmentalize the many different interconnected aspects of the boiling process -- from the channel geometry, to liquid and gas interactions, to underlying heat transfer mechanisms. The air bubble injection experiments were performed in annular and rectangular geometries and yielded data on bubble formation and departure from a small hole on the inner tube surface, subsequent motion and deformation of the detached bubbles, and interactions with laminar or turbulent water flow. Instantaneous and ensemble- average liquid velocity profiles have been obtained using a Particle Image Velocimetry technique and a high speed video camera. Reynolds numbers for these works ranged from 1,300 to 7,700. Boiling experiments have been performed with subcooled water at atmospheric pres- sure in the same annular channel geometry as the air injection experiments. A second flow loop with a slightly larger annular channel was constructed to perform further boiling experiments at elevated pressures up to 10 bar. High speed video and PIV measurements of turbulent velocity profiles in the presence of small vapor bubbles on the heated rod are presented. The liquid Reynolds number for this set of experiments ranged from 5,460 to 86,000. It was observed that as the vapor bubbles are very small compared to the injected air bubbles, further experiments were performed using a microscopic objective to obtain higher spatial resolution for velocity fields near the heated wall. Multiple correlations for the bubble liftoff diameter, liftoff time and bub- ble history number were evaluated against a number of experimental datasets from previous works, resulting in a

  13. La tuberculose abdominale pseudo-tumorale

    Science.gov (United States)

    El Barni, Rachid; Lahkim, Mohamed; Achour, Abdessamad

    2012-01-01

    Introduction L’objectif de ce travail est de rapporter cinq cas de tuberculose abdominale pseudo-tumorale afin d’en souligner les aspects diagnostiques et thérapeutiques. Cinq observations sont colligées dans le service de chirurgie générale de l’hôpital militaire Avicenne de Marrakech au cours de l’année 2007. Les aspects cliniques sont disparates. Ainsi, les auteurs ont noté un syndrome péritonéal dans un cas, une masse épigastrique dans un cas, une lésion suspect du sigmoïde dans un cas, une masse de la fosse iliaque droite dans un cas et une altération de l’état général avec fièvre dans le dernier cas. Un seul patient avaient bénéficié d’une biopsie scano-guidée et les quatre patients restants avaient été opérés. Une masse du méso côlon était notée dans le premier cas. Dans le second cas, l’aspect de la masse épigastrique et son siège avaient orienté vers une tumeur du grand omentum. Une localisation tuberculeuse péritonéale et sigmoïdienne avait été trouvée dans le troisième cas. Le diagnostic d’une tumeur du côlon droit était hautement suspect chez le patient séropositif qui avait présenté une péritonite post-opératoire et décédé à J + 3 dans un tableau de choc septique. Le siège et l’aspect nécrotique des lésions trouvées à la tomodensitométrie chez la seule patiente de l’étude avaient fait discuter en premier un lymphome. Même en l’absence d’antécédents de tuberculose pulmonaire, le diagnostic tuberculose abdominale pseudo-tumorale doit être évoqué surtout dans un pays d’endémie comme le notre et le recours à une laparotomie est justifié chaque fois que persiste un doute diagnostique ou en cas de complication. PMID:23330023

  14. The theory of pseudo-rigid bodies

    CERN Document Server

    Cohen, Harley

    1988-01-01

    This monograph concerns the development, analysis, and application of the theory of pseudo-rigid bodies. It collects together our work on that subject over the last five years. While some results have appeared else­ where, much of the work is new. Our objective in writing this mono­ graph has been to present a new theory of the deformation of bodies, one that has not only a firm theoretical basis, but also the simplicity to serve as an effective tool in practical problems. Consequently, the main body of the treatise is a multifaceted development of the theory, from foundations to explicit solutions to linearizations to methods of approximation. The fact that this variety of aspects, each examined in considerable detail, can be collected together in a single, unified treat­ ment gives this theory an elegance that we feel sets it apart from many others. While our goal has always been to give a complete treatment of the theory as it now stands, the work here is not meant to be definitive. Theories are not ent...

  15. Loop-Effects in Pseudo-Supersymmetry

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Matthias

    2002-11-01

    We analyze the transmission of supersymmetry breaking in brane-world models of pseudo-supersymmetry. In these models two branes preserve different halves of the bulk supersymmetry. Thus supersymmetry is broken although each sector of the model is supersymmetric when considered separately. The world-volume theory on one brane feels the breakdown of supersymmetry only through two-loop interactions involving a coupling to fields from the other brane. In a 5D toy model with bulk vectors, we compute the diagrams that contribute to scalar masses on one brane and find that the masses are proportional to the compactification scale up to logarithmic corrections, m{sup 2} {infinity} (2{pi}R){sup -2} (ln(2{pi}R m{sub S}) - 1.1), where m{sub s} is an ultraviolet cutoff. Thus, for large compactification radii, where this result is valid, the brane scalars acquire a positive mass squared. We also compute the three-loop diagrams relevant to the Casimir energy between the two branes and find E {infinity} (2{pi}R){sup -4}((ln(2{pi}R m{sub S}) - 1.7){sup 2} + 0.2). For large radii, this yields a repulsive Casimir force.

  16. Development of Flow Boiling and Condensation Experiment on the International Space Station- Normal and Low Gravity Flow Boiling Experiment Development and Test Results

    Science.gov (United States)

    Nahra, Henry K.; Hall, Nancy R.; Hasan, Mohammad M.; Wagner, James D.; May, Rochelle L.; Mackey, Jeffrey R.; Kolacz, John S.; Butcher, Robert L.; Frankenfield, Bruce J.; Mudawar, Issam; hide

    2013-01-01

    Flow boiling and condensation have been identified as two key mechanisms for heat transport that are vital for achieving weight and volume reduction as well as performance enhancement in future space systems. Since inertia driven flows are demanding on power usage, lower flows are desirable. However, in microgravity, lower flows are dominated by forces other than inertia (like the capillary force). It is of paramount interest to investigate limits of low flows beyond which the flow is inertial enough to be gravity independent. One of the objectives of the Flow Boiling and Condensation Flight Experiment sets to investigate these limits for flow boiling and condensation. A two-phase flow loop consisting of a Flow Boiling Module and two Condensation Modules has been developed to experimentally study flow boiling condensation heat transfer in the reduced gravity environment provided by the reduced gravity platform. This effort supports the development of a flow boiling and condensation facility for the International Space Station (ISS). The closed loop test facility is designed to deliver the test fluid, FC-72 to the inlet of any one of the test modules at specified thermodynamic and flow conditions. The zero-g-aircraft tests will provide subcooled and saturated flow boiling critical heat flux and flow condensation heat transfer data over wide range of flow velocities. Additionally, these tests will verify the performance of all gravity sensitive components, such as evaporator, condenser and accumulator associated with the two-phase flow loop. We will present in this paper the breadboard development and testing results which consist of detailed performance evaluation of the heater and condenser combination in reduced and normal gravity. We will also present the design of the reduced gravity aircraft rack and the results of the ground flow boiling heat transfer testing performed with the Flow Boiling Module that is designed to investigate flow boiling heat transfer and

  17. Heat transfer and visualization of falling film evaporation on a tube bundle

    Energy Technology Data Exchange (ETDEWEB)

    Christians, M.

    2010-07-01

    Horizontal falling film evaporators have the potential of displacing flooded evaporators in industry, due to advantages such as lower required refrigerant charge and lower pressure drop. However, there is a need to improve the understanding of falling film evaporation mechanisms to provide accurate thermal design methods. In this work, the existing LTCM falling film facility was utilized to perform falling film evaporation measurements on a single tube, a vertical row of horizontal tubes and a small tube bundle. Two enhanced boiling tubes, namely the Wolverine Turbo-B5 and the Wieland Gewa-B5, were tested using R-134a and R-236fa. The tests were carried out at a constant saturation temperature of T{sub sat} = 5 °C, liquid film Reynolds numbers ranging from 0 to 3000, and heat fluxes between 15 and 90 kW/m{sup 2} in pool boiling and falling film configurations. A visualization study was performed under adiabatic and diabatic conditions (in both single-array and bundle configurations) to study the flow. The physical phenomena governing the falling film evaporation process have been studied, and insight into their effects on the performance of tube bundles has been gained. Measurements of the local heat transfer coefficient were obtained and utilized to generate new prediction methods, including a method for predicting the onset-of-dryout film flow rate during falling film evaporation, local pool boiling and falling film heat transfer prediction methods and a falling film multiplier prediction method. (author)

  18. Hacerse y volverse como nexos pseudo-copulativos

    OpenAIRE

    Delbecque, Nicole; Van Gorp, Lise

    2013-01-01

    Cette contribution aborde les différences conceptuelles entre les pseudo-copules hacerse et volverse, partant des notions de «réalisation» et de «régression» qui caractérisent leurs emplois lexicaux. Esta contribución aborda las diferencias conceptuales entre las pseudo-cópulas hacerse y volverse, partiendo de las nociones de «realización» y de «regresión» que caracterizan sus empleos léxicos. This contribution tackles the conceptual differences between the pseudo-copulas hacerse and vo...

  19. Pseudo-Supersymmetry and the Domain-Wall/Cosmology Correspondence

    OpenAIRE

    Skenderis, K.; Townsend, P. K.

    2006-01-01

    The correspondence between domain-wall and cosmological solutions of gravity coupled to scalar fields is explained. Any domain wall solution that admits a Killing spinor is shown to correspond to a cosmology that admits a pseudo-Killing spinor: whereas the Killing spinor obeys a Dirac-type equation with hermitian `mass'-matrix, the corresponding pseudo-Killing spinor obeys a Dirac-type equation with a anti-hermitian `mass'-matrix. We comment on some implications of (pseudo)supersymmetry.

  20. Experimental study of heat transfer to falling liquid films

    Science.gov (United States)

    Fagerholm, N. E.; Kivioja, K.; Ghazanfari, A. R.; Jaervinen, E.

    1985-12-01

    This project was initiated in order to obtain more knowledge about thermal design of falling film heat exchangers and to find methods to improve heat transfer in film flow. A short literature survey of film flow characteristics and heat transfer is presented. An experimental apparatus designed and built for studying falling film evaporation is described. The first experiments were made with smooth Cu tube 25/22 mm and refrigerant R114 as evaporating liquid. A significant amount of droplet entrainment was observed during the tests. The measured average heat transfer coefficient varied from 1000 to 1800 W/m K when Re=1300 to 11000 respectively and when the transfer mode is surface evaporation. This could be predicted accurately with the experimental correlation of Chun and Seban. When nucleate boiling is dominant the heat transfer could be predicted well with pool boiling correlation of VDI-84.

  1. Pool Boiling Characteristics on the Microstructure surfaces with Both Rectangular Cavities and Channels

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Eok; Myung, Byung-Soo [Kyungpook Nat’l Univ., Daegu (Korea, Republic of); Park, Su Cheong; Yu, Dong In [POSTECH, Pohang (Korea, Republic of); Kim, Moo Hwan [Korea Institute of Nuclear Safety (KINS), Daejeon (Korea, Republic of); Ahn, Ho Seon [Incheon Nat’l Univ., Incheon (Korea, Republic of)

    2016-06-15

    Based on a surface design with rectangular cavities and channels, we investigated the effects of gravity and capillary pressure on pool-boiling Critical Heat Flux (CHF). The microcavity structures could prevent liquid flow by the capillary pressure effect. In addition, the microchannel structures contributed to induce one-dimensional liquid flow on the boiling surface. The relationship between the CHF and capillary flow was clearly established. The driving potentials for the liquid supply into a boiling surface can be generated by the gravitational head and capillary pressure. Through an analysis of pool boiling and visualization data, we reveal that the liquid supplement to maintain the nucleate boiling condition on a boiling surface is closely related to the gravitational pressure head and capillary pressure effect.

  2. DIRECT-CYCLE, BOILING-WATER NUCLEAR REACTOR

    Science.gov (United States)

    Harrer, J.M.; Fromm, L.W. Jr.; Kolba, V.M.

    1962-08-14

    A direct-cycle boiling-water nuclear reactor is described that employs a closed vessel and a plurality of fuel assemblies, each comprising an outer tube closed at its lower end, an inner tube, fuel rods in the space between the tubes and within the inner tube. A body of water lying within the pressure vessel and outside the fuel assemblies is converted to saturated steam, which enters each fuel assembly at the top and is converted to superheated steam in the fuel assembly while it is passing therethrough first downward through the space between the inner and outer tubes of the fuel assembly and then upward through the inner tube. (AEC)

  3. Acoustic monitoring of sodium boiling in a liquid metal fast breeder reactor from autoregressive models

    Energy Technology Data Exchange (ETDEWEB)

    Geraldo, Issa Cherif [Laboratoire d’Automatique, Génie Informatique et Signal (LAGIS UMR CNRS 8219), Université Lille 1, Sciences et technologies, Avenue Paul Langevin, BP 48, 59651 Villeneuve d’Ascq CEDEX (France); Bose, Tanmoy [Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal (India); Pekpe, Komi Midzodzi, E-mail: midzodzi.pekpe@univ-lille1.fr [Laboratoire d’Automatique, Génie Informatique et Signal (LAGIS UMR CNRS 8219), Université Lille 1, Sciences et technologies, Avenue Paul Langevin, BP 48, 59651 Villeneuve d’Ascq CEDEX (France); Cassar, Jean-Philippe [Laboratoire d’Automatique, Génie Informatique et Signal (LAGIS UMR CNRS 8219), Université Lille 1, Sciences et technologies, Avenue Paul Langevin, BP 48, 59651 Villeneuve d’Ascq CEDEX (France); Mohanty, A.R. [Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal (India); Paumel, Kévin [CEA, DEN, Nuclear Technology Department, F-13108 Saint-Paul-lez-Durance (France)

    2014-10-15

    Highlights: • The work deals with sodium boiling detection in a liquid metal fast breeder reactor. • The authors choose to use acoustic data instead of thermal data. • The method is designed to not to be disturbed by the environment noises. • A real time boiling detection methods are proposed in the paper. - Abstract: This paper deals with acoustic monitoring of sodium boiling in a liquid metal fast breeder reactor (LMFBR) based on auto regressive (AR) models which have low computational complexities. Some authors have used AR models for sodium boiling or sodium–water reaction detection. These works are based on the characterization of the difference between fault free condition and current functioning of the system. However, even in absence of faults, it is possible to observe a change in the AR models due to the change of operating mode of the LMFBR. This sets up the delicate problem of how to distinguish a change in operating mode in absence of faults and a change due to presence of faults. In this paper we propose a new approach for boiling detection based on the estimation of AR models on sliding windows. Afterwards, classification of the models into boiling or non-boiling models is made by comparing their coefficients by two statistical methods, multiple linear regression (LR) and support vectors machines (SVM). The proposed approach takes into account operating mode information in order to avoid false alarms. Experimental data include non-boiling background noise data collected from Phenix power plant (France) and provided by the CEA (Commissariat à l’Energie Atomique et aux énergies alternatives, France) and boiling condition data generated in laboratory. High boiling detection rates as well as low false alarms rates obtained on these experimental data show that the proposed method is efficient for boiling detection. Most importantly, it shows that the boiling phenomenon introduces a disturbance into the AR models that can be clearly detected.

  4. Numerical investigation of boiling heat transfer on hydrocarbon mixture refrigerant in vertical rectangular minichannel

    OpenAIRE

    Huixing Li; Yu Liu

    2016-01-01

    In order to investigate the characteristics of boiling heat transfer for hydrocarbon mixture refrigerant in plate-fin heat exchanger which is used in the petrochemical industry field, a model was established on boiling heat transfer in vertical rectangular channel. The simulated results were compared with the experimental data from literature. The results show that the deviation between the simulated results and experimental data is within ±15%. Meanwhile, the characteristic of boiling heat t...

  5. Experimental Investigation of Coolant Boiling in a Half-Heated Circular Tube - Final CRADA Report

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Wenhua [Argonne National Lab. (ANL), Argonne, IL (United States); Singh, Dileep [Argonne National Lab. (ANL), Argonne, IL (United States); France, David M. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-11-01

    Coolant subcooled boiling in the cylinder head regions of heavy-duty vehicle engines is unavoidable at high thermal loads due to high metal temperatures. However, theoretical, numerical, and experimental studies of coolant subcooled flow boiling under these specific application conditions are generally lacking in the engineering literature. The objective of this project was to provide such much-needed information, including the coolant subcooled flow boiling characteristics and the corresponding heat transfer coefficients, through experimental investigations.

  6. The effect of boiling water on disinfection by-product exposure.

    Science.gov (United States)

    Krasner, Stuart W; Wright, J Michael

    2005-03-01

    Chloraminated and chlorinated waters containing bromide were used to determine the impact of boiling on disinfection by-product (DBP) concentrations. No significant changes were detected in the concentrations of the dihalogenated haloacetic acids (DXAAs) (i.e., dichloro-, bromochloro-, dibromoacetic acid) upon boiling of chloraminated water, whereas the levels of the trihalogenated haloacetic acids (TXAAs) (i.e., trichloro- (TCAA), bromodichloro- (BDCAA), dibromochloroacetic acid (DBCAA)) decreased over time (e.g., 9-37% for TCAA). Increased DXAA concentrations (58-68%) were detected in the boiled chlorinated sample, which likely resulted from residual chlorine reacting with DXAA precursors. TCAA concentration was unchanged after boiling chlorinated water for 1 min, but a 30% reduction was observed after 5 min of boiling. BDCAA concentrations decreased 57% upon boiling for 1 min and were completely removed after 2 min of boiling, whereas DBCAA was removed after boiling chlorinated water for 1 min. Trihalomethane concentrations were reduced in both chloraminated (74-98%) and chlorinated (64-98%) water upon boiling. Boiling chloraminated water for 1 min reduced chloroform concentration by 75%. Chloroform was reduced by only 34% in chlorinated water after a 1 min boil, which indicates that simultaneous formation and volatilization of chloroform was occurring. Most of the remaining DBPs (e.g. haloketones, chloral hydrate, haloacetonitriles) were removed by at least 90% after 1 min of boiling in both samples. These data suggest that other mechanisms (e.g., hydrolysis) may have been responsible for removal of the non-volatile DBPs and further highlight the importance of examining individual species when estimating thermal effects on DBP concentrations.

  7. Pseudo-differential operators groups, geometry and applications

    CERN Document Server

    Zhu, Hongmei

    2017-01-01

    This volume consists of papers inspired by the special session on pseudo-differential operators at the 10th ISAAC Congress held at the University of Macau, August 3-8, 2015 and the mini-symposium on pseudo-differential operators in industries and technologies at the 8th ICIAM held at the National Convention Center in Beijing, August 10-14, 2015. The twelve papers included present cutting-edge trends in pseudo-differential operators and applications from the perspectives of Lie groups (Chapters 1-2), geometry (Chapters 3-5) and applications (Chapters 6-12). Many contributions cover applications in probability, differential equations and time-frequency analysis. A focus on the synergies of pseudo-differential operators with applications, especially real-life applications, enhances understanding of the analysis and the usefulness of these operators.

  8. Pseudo-Goldstone modes in isospin-asymmetric nuclear matter

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, T.D. [Univ. of Washington, Seattle, WA (United States); Broniowski, W. [H. Niewodniczanski Institute of Nuclear Physics, Cracow (Poland)

    1995-01-01

    The authors analyze the chiral limit in dense isospin-asymmetric nuclear matter. It is shown that the pseudo-Goldstone modes in this system are qualitatively different from the case of isospin-symmetric matter.

  9. Pseudo-Goldstone modes in isospin-asymmetric nuclear matter

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, T.D. [Washington Univ., Seattle, WA (United States). Dept. of Physics; Broniowski, W. [Institute of Nuclear Physics, Cracow (Poland)

    1994-12-01

    We analyze the chiral limit in dense isoptin-asymmetric nuclear matter. It is shown that the pseudo-Goldstone modes in this system are qualitatively different from the case of isospin-symmetric matter. (author). 20 refs.

  10. Her-entingen tegen Pseudo Vogelpest (NCD) op 'Het Spelderholt'

    NARCIS (Netherlands)

    Voorst, van A.

    1993-01-01

    Pseudo Vogelpest of NCD is een gevreesde virusziekte, waartegen een entverplichting geldt. Na het uitbreken van de ziekte in het zuiden van Nederland is al het volwassen pluimvee op Het Spelderholt opnieuw geënt.

  11. Pseudo-outbreak of Actinomyces graevenitzii associated with bronchoscopy.

    Science.gov (United States)

    Peaper, David R; Havill, Nancy L; Aniskiewicz, Michael; Callan, Deborah; Pop, Olivia; Towle, Dana; Boyce, John M

    2015-01-01

    Outbreaks and pseudo-outbreaks of infection related to bronchoscopy typically involve Gram-negative bacteria, Mycobacterium species or Legionella species. We report an unusual bronchoscopy-related pseudo-outbreak due to Actinomyces graevenitzii. Extensive epidemiological and microbiological investigation failed to identify a common source. Strain typing revealed that the cluster was comprised of heterogeneous strains of A. graevenitzii. A change in laboratory procedures for Actinomyces cultures was coincident with the emergence of the pseudo-outbreak, and we determined that A. graevenitzii isolates more readily adopted a white, dry, molar tooth appearance on anaerobic colistin nalidixic acid (CNA) agar which likely facilitated its detection and identification in bronchoscopic specimens. This unusual pseudo-outbreak was related to frequent requests of bronchoscopists for Actinomyces cultures combined with a change in microbiology laboratory practices. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  12. Enhanced pool boiling critical heat flux induced by capillary wicking effect of a Cr-sputtered superhydrophilic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Son, Hong Hyun; Seo, Gwang Hyeok; Kim, Sung Joong [Hanyang University, Seoul (Korea, Republic of)

    2016-10-15

    In light of boiling heat transfer, the smooth surface potentially reduces active nucleation of bubbles and rewetting of dry spots near the critical heat flux (CHF). This kind of process is highly likely to deteriorate the CHF. Thus, it is essential to produce appropriate microstructures on the surface for the enhancement of the CHF. In this study, to investigate the microstructural effect of thin film-fabricated surfaces on the pool boiling CHF, we controlled the surface roughness in a narrow range of 0.1-0.25 μm and its morphologies, in the form of micro-scratches using PVD sputtering technique. Specifically for DC magnetron sputtering, pure chromium (Cr) was selected as a target material owing to its high oxidation resistance. In order to analyze the CHF trend with changes in roughness, we introduced existing capillary wicking-based models because superhydrophilic characteristics of microstructures are highly related to the capillary wicking behaviors in micro-flow channels. After Cr sputtering under given conditions, the Cr-sputtered surfaces showed superhydrophilic characteristics and its capability became more enhanced with an increase of surface roughness. Judging from spreading behavior of a liquid droplet, the presence of micro-wicking channels, coupled with Cr nanostructures, effectively enhanced the advancing rate of drop base diameter. The CHF exhibited an increasing trend with increasing surface roughness. However, the enhancement ratio agreed poorly with the predictions of the roughness factor-based models, all of which originated from a conventional static force balance.

  13. Pseudo-telepathy: input cardinality and Bell-type inequalities

    OpenAIRE

    Gisin, Nicolas; Methot, André; Scarani, Valerio

    2006-01-01

    Pseudo-telepathy is the most recent form of rejection of locality. Many of its properties have already been discovered: for instance, the minimal entanglement, as well as the minimal cardinality of the output sets, have been characterized. This paper contains two main results. First, we prove that no bipartite pseudo-telepathy game exists, in which one of the partners receives only two questions; as a corollary, we show that the minimal "input cardinality", that is, the minimal number of ques...

  14. Maximally entangled states in pseudo-telepathy games

    OpenAIRE

    Mančinska, Laura

    2015-01-01

    A pseudo-telepathy game is a nonlocal game which can be won with probability one using some finite-dimensional quantum strategy but not using a classical one. Our central question is whether there exist two-party pseudo-telepathy games which cannot be won with probability one using a maximally entangled state. Towards answering this question, we develop conditions under which maximally entangled states suffice. In particular, we show that maximally entangled states suffice for weak projection...

  15. On Some (Pseudo) Involutions in the Riordan Group

    Science.gov (United States)

    Cameron, Naiomi T.; Nkwanta, Asamoah

    2005-08-01

    In this paper, we address a question posed by L. Shapiro regarding algebraic and/or combinatorial characterizations of the elements of order 2 in the Riordan group. We present two classes of combinatorial matrices having pseudo-order 2. In one class, we find generalizations of Pascal's triangle and use some special cases to discover and prove interesting identities. In the other class, we find generalizations of Nkwanta's RNA triangle and show that they are pseudo-involutions.

  16. Diagnosis and Treatment of Pseudo-Class III Malocclusion

    OpenAIRE

    Ariel Reyes; Luis Serret; Marcos Peguero; Orlando Tanaka

    2014-01-01

    Pseudo-Class III malocclusion is characterized by the presence of an anterior crossbite due to a forward functional displacement of the mandible; in most cases, the maxillary incisors present some degree of retroclination, and the mandibular incisors are proclined. Various types of appliances have been described in the literature for the early treatment of pseudo-Class III malocclusion. The objectives of this paper are to demonstrate the importance of making the differential diagnosis between...

  17. Study of gray image pseudo-color processing algorithms

    Science.gov (United States)

    Hu, Jinlong; Peng, Xianrong; Xu, Zhiyong

    In gray images which contain abundant information, if the differences between adjacent pixels' intensity are small, the required information can not be extracted by humans, since humans are more sensitive to color images than gray images. If gray images are transformed to pseudo-color images, the details of images will be more explicit, and the target will be recognized more easily. There are two methods (in frequency field and in spatial field) to realize pseudo-color enhancement of gray images. The first method is mainly the filtering in frequency field, and the second is the equal density pseudo-color coding methods which mainly include density segmentation coding, function transformation and complementary pseudo-color coding. Moreover, there are many other methods to realize pseudo-color enhancement, such as pixel's self-transformation based on RGB tri-primary, pseudo-color coding from phase-modulated image based on RGB color model, pseudo-color coding of high gray-resolution image, et al. However, above methods are tailored to a particular situation and transformations are based on RGB color space. In order to improve the visual effect, the method based on RGB color space and pixels' self-transformation is improved in this paper, which is based on HIS color space. Compared with other methods, some gray images with ordinary formats can be processed, and many gray images can be transformed to pseudo-color images with 24 bits. The experiment shows that the processed image has abundant levels, which is consistent with human's perception.

  18. Gastric pseudo-ulcers: membrana angularis and pyloric torus defects.

    Science.gov (United States)

    Peavy, P W; Clements, J L; Weens, H S

    1975-03-01

    The membrana angularis and pyloric torus defects are two physiologic bulges which can simulate ulcerations along the lesser curvature of the stomach. The muscular anatomy of the stomach and the mechanism which produces these pseudo-ulcers are discussed. Both pseudoniches can be seen transiently in normal individuals but occasionally are such prominence as to become diagnostic pitfalls. The features and significance of each pseudo-ulcer are reviewed in an attempt to facilitate recognition on the upper gastrointestinal barium examination.

  19. Pseudo-Hermitian quantum mechanics with unbounded metric operators.

    Science.gov (United States)

    Mostafazadeh, Ali

    2013-04-28

    I extend the formulation of pseudo-Hermitian quantum mechanics to η(+)-pseudo-Hermitian Hamiltonian operators H with an unbounded metric operator η(+). In particular, I give the details of the construction of the physical Hilbert space, observables and equivalent Hermitian Hamiltonian for the case that H has a real and discrete spectrum and its eigenvectors belong to the domain of η(+) and consequently √η(+).

  20. Study of pool boiling of distilled water on SiO2 nanoparticle-coated wire

    Science.gov (United States)

    Pryazhnikov, M. I.; Minakov, A. V.

    2017-11-01

    Experimental results of pool boiling of distilled water on bare nichrome wire and SiO2 nanoparticle-coated wire are presented. Nano-coated wires were obtained by first boiling them in SiO2-water nanofluid. The nanofluid was prepared based on distilled water and SiO2 nanoparticles. The average size of the nanoparticles was 100 nm. The volume concentration of particles was equal 2%. Boiling curves of distilled water were obtained on bare nichrome wire and SiO2 nanoparticles coated wire. The coating increased the critical heat flux during boiling of water.

  1. MTD-MFC: unified framework for investigation of diversity of boiling heat transfer curves

    Energy Technology Data Exchange (ETDEWEB)

    Shekriladze, I.G. [Georgian Technical University, Tbilisi (Georgia)], e-mail: shekri@geo.net.ge

    2009-07-01

    A keynote paper presents just the next attempt to promote a discussion of modern state of art in the field of boiling heat transfer research. It is shown how longstanding disregard of internal contradictions of applicable approaches has resulted theoretical deadlock. Alternatively, it also is shown how resolution of these contradictions opens the ways to breakthrough in boiling heat transfer theory. Basic experimental facts, physical models and correlations are reconsidered. Principal contradictions between experimental knowledge and traditional model of 'the theatre of actors' (MTA) are discussed. Crucial role of pumping effect of growing bubble (PEGB) in boiling heat transfer and hydrodynamics is shown. Basic role of control of HTC by thermodynamic conditions on nucleation sites is demonstrated and consequent model of 'the theatre of director' (MTD) is discussed. Universal MTD-based correlation of boiling HTC of all types of liquids is considered. Unified consistent research framework for developed boiling heat transfer and diverse specific boiling heat transfer regimes is outlined through supplementing MTD by so-called multifactoring concept (MFC). The latter links transition from developed boiling mode to diverse boiling curves to a phenomenon of multiplication of factors influencing HTC. The ways of further research of the boiling problem are discussed. (author)

  2. Corrosion Behavior of Amorphous Nickel-Valve Metal Alloys in Boiling Concentrated Nitric and Hydrochloric Acids

    OpenAIRE

    Kazuo, SHIMAMURA; Asahi, Kawashima; Katsuhiko, Asami; Koji, Hashimoto; Mitsui Engineering & Shipbuilding Co., Ltd.; The Research Institute for Iron, Steel and Other Metals

    1986-01-01

    The corrosion behavior of amorphous nickel-base alloys containing titanium, zirconium, niobium, tantalum and/or phosphorus in boiling 9 N HNO_3 solutions with and without Cr^ ion and in a boiling 6 N HCl solution was investigated. In boiling 9 N HNO_3 solutions alloys containing 20 at% or more tantalum were immune to corrosion, maintaining the metallic luster, and Ni-40~60Nb alloys showed low corrosion rates of the order of μm/year. In the boiling 6 N HCl solution only tantalum-containing all...

  3. Corrosion Behavior of Amorphous Nickel-Valve Metal Alloys in Boiling Concentrated Nitric and Hydrochloric Acids

    OpenAIRE

    Shimamura, Kazuo; Kawashima, Asahi; ASAMI, Katsuhiko; Hashimoto, Koji

    1986-01-01

    The corrosion behavior of amorphous nickel-base alloys containing titanium, zirconium, niobium, tantalum and/or phosphorus in boiling 9 N HNO_3 solutions with and without Cr^ ion and in a boiling 6 N HCl solution was investigated. In boiling 9 N HNO_3 solutions alloys containing 20 at% or more tantalum were immune to corrosion, maintaining the metallic luster, and Ni-40?60Nb alloys showed low corrosion rates of the order of μm/year. In the boiling 6 N HCl solution only tantalum-containing all...

  4. "Pseudo" nomenclature in dermatology: What′s in a name?

    Directory of Open Access Journals (Sweden)

    Sangita Ghosh

    2013-01-01

    Full Text Available In the bewildering array of scientific nomenclature in the medical field, it is important to use correct terminology, know their aberrations and the reason behind a specific terminology. This paper is an attempt towards compiling all the pseudo-nomenclatures coined in dermatology, in order to make it easier to retain and recollect these pseudo names, signs, morphology, diseases, and conditions. It is also imperative to know the true entities that these pseudo names masquerade as, so as to understand the explanation for assigning the term ′pseudo′ to these conditions. A total of 52 pseudo-terms have been compiled here in reference to dermatology. Most of these pseudo-nomenclatures were coined due to some clinical or histopathological resemblance to the true conditions, while some were premature conclusions drawn from a flawed understanding of the basic nature of the condition. Clear understanding of each of these terms and the explanation behind them being pseudo will enable a dermatologist to avoid misdiagnosis and needless confusion.

  5. Development and Capabilities of ISS Flow Boiling and Condensation Experiment

    Science.gov (United States)

    Nahra, Henry; Hasan, Mohammad; Balasubramaniam, R.; Patania, Michelle; Hall, Nancy; Wagner, James; Mackey, Jeffrey; Frankenfield, Bruce; Hauser, Daniel; Harpster, George; hide

    2015-01-01

    An experimental facility to perform flow boiling and condensation experiments in long duration microgravity environment is being designed for operation on the International Space Station (ISS). This work describes the design of the subsystems of the FBCE including the Fluid subsystem modules, data acquisition, controls, and diagnostics. Subsystems and components are designed within the constraints of the ISS Fluid Integrated Rack in terms of power availability, cooling capability, mass and volume, and most importantly the safety requirements. In this work we present the results of ground-based performance testing of the FBCE subsystem modules and test module which consist of the two condensation modules and the flow boiling module. During this testing, we evaluated the pressure drop profile across different components of the fluid subsystem, heater performance, on-orbit degassing subsystem, heat loss from different modules and components, and performance of the test modules. These results will be used in the refinement of the flight system design and build-up of the FBCE which is manifested for flight in late 2017-early 2018.

  6. Boiling water neutronic reactor incorporating a process inherent safety design

    Science.gov (United States)

    Forsberg, C.W.

    1985-02-19

    A boiling-water reactor core is positioned within a prestressed concrete reactor vessel of a size which will hold a supply of coolant water sufficient to submerge and cool the reactor core by boiling for a period of at least one week after shutdown. Separate volumes of hot, clean (nonborated) water for cooling during normal operation and cool highly borated water for emergency cooling and reactor shutdown are separated by an insulated wall during normal reactor operation with contact between the two water volumes being maintained at interfaces near the top and bottom ends of the reactor vessel. Means are provided for balancing the pressure of the two water volumes at the lower interface zone during normal operation to prevent entry of the cool borated water into the reactor core region, for detecting the onset of excessive power to coolant flow conditions in the reactor core and for detecting low water levels of reactor coolant. Cool borated water is permitted to flow into the reactor core when low reactor coolant levels or excessive power to coolant flow conditions are encountered.

  7. Water inventory management in condenser pool of boiling water reactor

    Science.gov (United States)

    Gluntz, Douglas M.

    1996-01-01

    An improved system for managing the water inventory in the condenser pool of a boiling water reactor has means for raising the level of the upper surface of the condenser pool water without adding water to the isolation pool. A tank filled with water is installed in a chamber of the condenser pool. The water-filled tank contains one or more holes or openings at its lowermost periphery and is connected via piping and a passive-type valve (e.g., squib valve) to a high-pressure gas-charged pneumatic tank of appropriate volume. The valve is normally closed, but can be opened at an appropriate time following a loss-of-coolant accident. When the valve opens, high-pressure gas inside the pneumatic tank is released to flow passively through the piping to pressurize the interior of the water-filled tank. In so doing, the initial water contents of the tank are expelled through the openings, causing the water level in the condenser pool to rise. This increases the volume of water available to be boiled off by heat conducted from the passive containment cooling heat exchangers. 4 figs.

  8. The decrease of cylindrical pempek quality during boiling

    Science.gov (United States)

    Karneta, R.; Gultom, N. F.

    2017-09-01

    The research objective was to study the effects of temperature and formulation on quality of pempek lenjer during boiling. Treatments in this study were four levels of pempek formulation and five levels of temperature. Data was processed by using analysis of variance (Anova). If test results showed that samples were significantly different or highly significantly different, then further test was conducted by using Honestly Significant Different. The results showed that chemical analysis showed that fish dominant formula of cylindrical pempek had higher water content, protein content, lipid content and ash content than that of tapioca starch dominant formula, but it had lower carbohydrate content and fibre content than that of tapioca starch dominant formula.The higher the temperature at center point of cylindrical pempek, the lower the chemical quality of cylindrical pempek. The effect of formula on physical quality of cylindrical pempek showed that tapioca starch dominant formula had more rubbery texture, more neutral pH and brighter color than that of fish dominant formula.The temperature change had no significant effect on texture and pH of cylindrical pempek, but it had significant effect on lightness, intensity and chromatic color especially after exceeding optimum time of boiling.

  9. Nucleate boiling pressure drop in an annulus: Book 5

    Energy Technology Data Exchange (ETDEWEB)

    1992-11-01

    The application of the work described in this report is the production reactors at the Savannah River Site, and the context is nuclear reactor safety. The Loss of Coolant Accident (LOCA) scenario considered involves a double-ended break of a primary coolant pipe in the reactor. During a LOCA, the flow through portions of the reactor may reverse direction or be greatly reduced, depending upon the location of the break. The reduced flow rate of coolant (D{sub 2}O) through the fuel assembly channels of the reactor -- downflow in this situation -- can lead to boiling and to the potential for flow instabilities which may cause some of the fuel assembly channels to overheat and melt. That situation is to be avoided. The experimental approach is to provide a test annulus which simulates geometry, materials, and flow conditions in a Mark-22 fuel assembly (Coolant Channel 3) to the extent possible. The key analysis approaches are: To compare the minima in the measured demand curves with analytical criteria, in particular the Saha-Zuber (1974) model; and to compare the pressure and temperature as a function of length in the annulus with an integral model for flow boiling in a heated channel. Nineteen test series and a total of 178 tests were performed. Testing addressed the effects of: Heat flux; pressure; helium gas; power tilt; ribs; asymmetric heat flux. This document consists solely of the plato file index from 11/87 to 11/90.

  10. Effect of size sprinkled heat exchange surface on developing boiling

    Directory of Open Access Journals (Sweden)

    Petr Kracík

    2016-06-01

    Full Text Available This article presents research of sprinkled heat exchangers. This type of research has become rather topical in relation to sea water desalination. This process uses sprinkling of exchangers which rapidly separates vapour phase from a liquid phase. Applications help better utilize low-potential heat which is commonly wasted in utility systems. Low-potential heat may increase utilization of primary materials. Our ambition is to analyse and describe the whole sprinkled exchanger. Two heat exchangers were tested with a similar tube pitch: heat exchanger no. 1 had a four-tube bundle and heat exchanger no. 2 had eight-tube bundle. Efforts were made to maintain similar physical characteristics. They were tested at two flow rates (ca 0.07 and 0.11 kg s−1 m−1 and progress of boiling on the bundle was observed. Initial pressure was ca 10 kPa (abs at which no liquid was boiling at any part of the exchanger; the pressure was then lowered. Other input parameters were roughly similar for both flow rates. Temperature of heating water was ca 50°C at a constant flow rate of ca 7.2 L min−1. Results of our experiments provide optimum parameters for the given conditions for both tube bundles.

  11. Applications of the pseudo-harmonics to the multidimensional kinetics; Aplicacao do metodo dos pseudo-harmonicos a cinetica multidimensional

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Zelmo Rodrigues de; Silva, Fernando Carvalho da; Alvim, Antonio C. Marques [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Nuclear]. E-mail: zelmo@con.ufrj.br; fernando@con.ufrj.br; alvim@con.ufrj.br

    2005-07-01

    In this work we propose the application of the pseudo-harmonics in modal methods of spatial kinetics. The pseudo-harmonics, or the pseudo-modes, are the eigenfunctions associated to the leakage+removal operator in each group of energy of the steady-state diffusion equation. This operator is self-adjoint and it is not necessary to calculate the adjoints eigenfunctions. In the present work the pseudo-harmonics will be obtained starting from the equation of diffusion discretized by the coarse-mesh finite difference (CMFD). The modal methods approximate the time-dependent flux for an expansion in functions predetermined, that include the spatial dependence, with unknown expansion coefficients, that include the whole dependent part of the time. The obtaining of the system whose solution they are the coefficients of the modal expansion is done with aid of a function weight. Using the pseudomodes obtained in the steady state calculations, in the modal expansion as been the dependent functions of the space, we will show that the function weight can be chosen as being the own adjoint pseudo-modes. This calculation leads to a linear system of ordinary differential equations with the defined dimension for the number of pseudo-harmonics employed. The solution of the equations is built through the analytical integration of the equations of the precursor of delayed neutron. The proposed method was tested and it present good results, when compared with the direct method. (author)

  12. Fundamental study of FC-72 pool boiling surface temperature fluctuations and bubble behavior

    Science.gov (United States)

    Griffin, Alison R.

    A heater designed to monitor surface temperature fluctuations during pool boiling experiments while the bubbles were simultaneously being observed has been fabricated and tested. The heat source was a transparent indium tin oxide (ITO) layer commercially deposited on a fused quartz substrate. Four copper-nickel thin film thermocouples (TFTCs) on the heater surface measured the surface temperature, while a thin layer of sapphire or fused silica provided electrical insulation between the TFTCs and the ITO. The TFTCs were micro-fabricated using the liftoff process to deposit the nickel and copper metal films. The TFTC elements were 50 mum wide and overlapped to form a 25 mum by 25 mum junction. TFTC voltages were recorded by a DAQ at a sampling rate of 50 kHz. A high-speed CCD camera recorded bubble images from below the heater at 2000 frames/second. A trigger sent to the camera by the DAQ synchronized the bubble images and the surface temperature data. As the bubbles and their contact rings grew over the TFTC junction, correlations between bubble behavior and surface temperature changes were demonstrated. On the heaters with fused silica insulation layers, 1--2°C temperature drops on the order of 1 ms occurred as the contact ring moved over the TFTC junction during bubble growth and as the contact ring moved back over the TFTC junction during bubble departure. These temperature drops during bubble growth and departure were due to microlayer evaporation and liquid rewetting the heated surface, respectively. Microlayer evaporation was not distinguished as the primary method of heat removal from the surface. Heaters with sapphire insulation layers did not display the measurable temperature drops observed with the fused silica heaters. The large thermal diffusivity of the sapphire compared to the fused silica was determined as the reason for the absence of these temperature drops. These findings were confirmed by a comparison of temperature drops in a 2-D simulation of

  13. When Is "Pseudo-Ludwig's Angina" Associated With Coagulopathy Also a "Pseudo" Hemorrhage?

    Science.gov (United States)

    Lovallo, Emily; Patterson, Sarah; Erickson, Mitchel; Chin, Cynthia; Blanc, Paul; Durrani, Timur S

    2013-01-01

    Sublingual hematoma secondary to short-acting anticoagulants such as warfarin has been labeled "pseudo-Ludwig's angina" to distinguish it from the classic syndrome of localized infection and swelling involving the upper airway. Sublingual hematoma with airway compromise secondary to brodifacoum, a common long-acting anticoagulant rodenticide, has only been reported in the veterinary literature. We report a case of massive tongue swelling and impending airway compromise in the context of an intentional long-acting anticoagulant ingestion leading to coagulopathy. The swelling was initially presumed to be due either to infection or hemorrhage, but this was not supported by computed tomography scan imaging. Instead, the patient's clinical course was consistent with corticosteroid-responsive angioedema, temporally associated with the ingested brodifacoum.

  14. High conversion pressurized water reactor with boiling channels

    Energy Technology Data Exchange (ETDEWEB)

    Margulis, M., E-mail: maratm@post.bgu.ac.il [The Unit of Nuclear Engineering, Ben Gurion University of the Negev, POB 653, Beer Sheva 84105 (Israel); Shwageraus, E., E-mail: es607@cam.ac.uk [Department of Engineering, University of Cambridge, CB2 1PZ Cambridge (United Kingdom)

    2015-10-15

    Highlights: • Conceptual design of partially boiling PWR core was proposed and studied. • Self-sustainable Th–{sup 233}U fuel cycle was utilized in this study. • Seed-blanket fuel assembly lattice optimization was performed. • A coupled Monte Carlo, fuel depletion and thermal-hydraulics studies were carried out. • Thermal–hydraulic analysis assured that the design matches imposed safety constraints. - Abstract: Parametric studies have been performed on a seed-blanket Th–{sup 233}U fuel configuration in a pressurized water reactor (PWR) with boiling channels to achieve high conversion ratio. Previous studies on seed-blanket concepts suggested substantial reduction in the core power density is needed in order to operate under nominal PWR system conditions. Boiling flow regime in the seed region allows more heat to be removed for a given coolant mass flow rate, which in turn, may potentially allow increasing the power density of the core. In addition, reduced moderation improves the breeding performance. A two-dimensional design optimization study was carried out with BOXER and SERPENT codes in order to determine the most attractive fuel assembly configuration that would ensure breeding. Effects of various parameters, such as void fraction, blanket fuel form, number of seed pins and their dimensions, on the conversion ratio were examined. The obtained results, for which the power density was set to be 104 W/cm{sup 3}, created a map of potentially feasible designs. It was found that several options have the potential to achieve end of life fissile inventory ratio above unity, which implies potential feasibility of a self-sustainable Thorium fuel cycle in PWRs without significant reduction in the core power density. Finally, a preliminary three-dimensional coupled neutronic and thermal–hydraulic analysis for a single seed-blanket fuel assembly was performed. The results indicate that axial void distribution changes drastically with burnup. Therefore

  15. Characterization and monitoring of pseudo-polymorphs in manufacturing process by NIR.

    Science.gov (United States)

    Kamada, Kenji; Yoshimura, Shiho; Murata, Masami; Murata, Hiroshi; Nagai, Hiroshi; Ushio, Hidetoshi; Terada, Katsuhide

    2009-02-23

    Moisture-sensitive pseudo-polymorphs with different stabilities were characterized, and their polymorphisms were monitored in the process of tableting and film coating by near-infrared (NIR) spectroscopy. In this study, we proved that we could successfully maintain the crystal form ratio in the tablet by controlling the moisture profile during the manufacture to sufficiently stabilize the drug product. Mitemcinal fumarate is an erythromycin derivative with two pseudo-polymorphic forms, hydrate and anhydrate. We characterized them by X-ray powder diffraction and water sorption isotherm plot analysis. Stability test revealed that the hydrate form is more stable than the anhydrate form. We established a quantitative method by using NIR and monitored the hydrate form ratio in the tablet during the tableting and coating process. The manufacturing room was controlled to between 40 and 60% RH. Although the hydrate form ratio just after the onset of tableting decreased to below 40%, 60% was obtained at the end of the final process which sufficiently retains stability. Transition of the hydrate form ratio during the manufacturing process was reasonable; this indicates that our NIR method is suitable for monitoring. Thus, NIR is one of the most suitable tools for in-process testing of these humidity-sensitive APIs.

  16. The cholesterol-raising factor from boiled coffee does not pass a paper filter.

    NARCIS (Netherlands)

    Dusseldorp, van M.; Katan, M.B.; Vliet, van T.; Demacker, P.N.M.; Stalenhoef, A.F.H.

    1991-01-01

    Previous studies have indicated that consumption of boiled coffee raises total and low density lipoprotein (LDL) cholesterol, whereas drip-filtered coffee does not. We have tested the effect on serum lipids of consumed coffee that was first boiled and then filtered through commercial paper coffee

  17. 78 FR 46378 - La Crosse Boiling Water Reactor, Environmental Assessment and Finding of No Significant Impact...

    Science.gov (United States)

    2013-07-31

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION La Crosse Boiling Water Reactor, Environmental Assessment and Finding of No Significant Impact... of Title 10 of the Code of Federal Regulations (10 CFR) for the La Crosse Boiling Water Reactor...

  18. 77 FR 27097 - LaCrosse Boiling Water Reactor, Exemption From Certain Requirements, Vernon County, WI

    Science.gov (United States)

    2012-05-08

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION LaCrosse Boiling Water Reactor, Exemption From Certain Requirements, Vernon County, WI AGENCY...) 73.55, for the LaCrosse Boiling Water Reactor (LACBWR). This Environmental Assessment (EA) has been...

  19. 76 FR 61118 - Meeting of the ACRS Subcommittee on Advanced Boiling Water Reactor; Notice of Meeting

    Science.gov (United States)

    2011-10-03

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Advisory Committee on Reactor Safeguards (ACRS) Meeting of the ACRS Subcommittee on Advanced Boiling Water Reactor; Notice of Meeting The ACRS Subcommittee on Advanced Boiling Water Reactor (ABWR...

  20. 46 CFR 154.706 - Cargo boil-off as fuel: Fuel lines.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo boil-off as fuel: Fuel lines. 154.706 Section 154... Equipment Cargo Pressure and Temperature Control § 154.706 Cargo boil-off as fuel: Fuel lines. (a) Gas fuel lines must not pass through accommodation, service, or control spaces. Each gas fuel line passing...

  1. Numerical investigation of boiling heat transfer on hydrocarbon mixture refrigerant in vertical rectangular minichannel

    Directory of Open Access Journals (Sweden)

    Huixing Li

    2016-05-01

    Full Text Available In order to investigate the characteristics of boiling heat transfer for hydrocarbon mixture refrigerant in plate-fin heat exchanger which is used in the petrochemical industry field, a model was established on boiling heat transfer in vertical rectangular channel. The simulated results were compared with the experimental data from literature. The results show that the deviation between the simulated results and experimental data is within ±15%. Meanwhile, the characteristic of boiling heat transfer was investigated in vertical rectangular minichannel of plate-fin heat exchanger. The results show that the boiling heat transfer coefficient increases with the increase in quality and mass flux and is slightly impacted by the heat flux. This is because that the main boiling mechanism is forced convective boiling while the contribution of nucleate boiling is slight. The correlation of Liu and Winterton is in good agreement with the simulation results. The deviation between correlation calculations and simulation results is mostly less than ±15%. These results will provide some constructive instructions for the understanding of saturated boiling mechanism in a vertical rectangular minichannel and the prediction of heat transfer performance in plate-fin heat exchanger.

  2. Introduction of image analysis for the quantification of the boiling flow heat transfer

    NARCIS (Netherlands)

    Ferret, C.; Falk, L.; d'Ortona, U.; Chenu, A.; Veenstra, T.T.

    2004-01-01

    Heat transfer performances for non-boiling and boiling flow of a micro-vaporizer have been measured by standard methods (temperatures, flow rates, effective power input). The study was carried out for laminar flow (Re<25) in silicon micro-channels (5 mm×3 cm×200 μm) filled with ordered obstacles to

  3. Theoretical and experimental investigation into the explosive boiling potential of thermally stratified liquid-liquid systems

    NARCIS (Netherlands)

    Fabiano, B.; Kersten, R.J.A.; Opschoor, G.; Pastorino, R.

    2002-01-01

    The occurrence of a rapid phase transition, or so-called explosive boiling, when a cold volatile liquid comes into contact with a hot liquid or hot surface is a potential hazard in industry. This study was focused on the explosive boiling potential of thermally stratified liquid-liquid systems that

  4. Microwave super-heated boiling of organic liquids: Origin, effect and application

    NARCIS (Netherlands)

    Chemat, F.; Esveld, E.

    2001-01-01

    This paper reports the state of the art of the microwave super-heated boiling phenomenon. When a liquid is heated by microwaves, the temperature increases rapidly to reach a steady temperature while refluxing. It happens that this steady state temperature can be up to 40 K higher than the boiling

  5. The effects of boiling on the allergenic properties of tropomyosin of shrimp (litopenaeus vannamei).

    Science.gov (United States)

    Shrimp play an important role in human nutrition, and is responsible for severe hypersensitivity reactions. The thermal stability of raw and boiled shrimp tropomyosins (TM) has never been reported. The aims of the study were to compare the stability of raw and boiled shrimp TM of Litopenaeus vanname...

  6. Two-phase flow boiling in small channels: A brief review

    Indian Academy of Sciences (India)

    Boiling flows are encountered in a wide range of industrial applications such as boilers, core and steam generators in nuclear reactors, petroleum transportation, electronic cooling and various types of chemical reactors. Many of these applications involve boiling flows in conventional channels (channel size ≥ 3 mm).

  7. Replacement Value of Soybean Meal and Maize with Raw or Boiled ...

    African Journals Online (AJOL)

    Replacement Value of Soybean Meal and Maize with Raw or Boiled Pigeon Pea Seed Meal in Exotic Pullet Diets. ... Nigerian Journal of Animal Science ... Abstract. A study to determine the replacement value of raw or boiled pigeon pea seed meal (PSM) for soybean meal and maize in the diets of exotic pullets (1-56 d) was ...

  8. Thermodynamic and Gasdynamic Aspects of a Boiling Liquid Expanding Vapour Explosion

    NARCIS (Netherlands)

    Xie, M.

    2013-01-01

    The risk of explosion due to rupture of a tank filled with pressurized liquefied gas (PLG) is one of the risks to be considered in the context of studies on tunnel safety. When a vessel containing liquid well above its boiling point at normal atmospheric pressure fails catastrophically a Boiling

  9. Theoretical modeling of CHF for near-saturated pool boiling and flow boiling from short heaters using the interfacial lift-off criterion

    Energy Technology Data Exchange (ETDEWEB)

    Mudawar, I.; Galloway, J.E.; Gersey, C.O. [Purdue Univ., West Lafayette, IN (United States)] [and others

    1995-12-31

    Pool boiling and flow boiling were examined for near-saturated bulk conditions in order to determine the critical heat flux (CHF) trigger mechanism for each. Photographic studies of the wall region revealed features common to both situations. At fluxes below CHF, the vapor coalesces into a wavy layer which permits wetting only in wetting fronts, the portions of the liquid-vapor interface which contact the wall as a result of the interfacial waviness. Close examination of the interfacial features revealed the waves are generated from the lower edge of the heater in pool boiling and the heater`s upstream region in flow boiling. Wavelengths follow predictions based upon the Kelvin-Helmholtz instability criterion. Critical heat flux in both cases occurs when the pressure force exerted upon the interface due to interfacial curvature, which tends to preserve interfacial contact with the wall prior to CHF, is overcome by the momentum of vapor at the site of the first wetting front, causing the interface to lift away from the wall. It is shown this interfacial lift-off criterion facilitates accurate theoretical modeling of CHF in pool boiling and in flow boiling in both straight and curved channels.

  10. Pseudo-Newtonian planar circular restricted 3-body problem

    Energy Technology Data Exchange (ETDEWEB)

    Dubeibe, F.L., E-mail: fldubeibem@unal.edu.co [Facultad de Ciencias Humanas y de la Educación, Universidad de los Llanos, Villavicencio (Colombia); Grupo de Investigación en Relatividad y Gravitación, Escuela de Física, Universidad Industrial de Santander, A.A. 678, Bucaramanga (Colombia); Lora-Clavijo, F.D., E-mail: fadulora@uis.edu.co [Grupo de Investigación en Relatividad y Gravitación, Escuela de Física, Universidad Industrial de Santander, A.A. 678, Bucaramanga (Colombia); González, Guillermo A., E-mail: guillermo.gonzalez@saber.uis.edu.co [Grupo de Investigación en Relatividad y Gravitación, Escuela de Física, Universidad Industrial de Santander, A.A. 678, Bucaramanga (Colombia)

    2017-02-12

    We study the dynamics of the planar circular restricted three-body problem in the context of a pseudo-Newtonian approximation. By using the Fodor–Hoenselaers–Perjés procedure, we perform an expansion in the mass potential of a static massive spherical source up to the first non-Newtonian term, giving place to a gravitational potential that includes first-order general relativistic effects. With this result, we model a system composed by two pseudo-Newtonian primaries describing circular orbits around their common center of mass, and a test particle orbiting the system in the equatorial plane. The dynamics of the new system of equations is studied in terms of the Poincaré section method and the Lyapunov exponents, where the introduction of a new parameter ϵ, allows us to observe the transition from the Newtonian to the pseudo-Newtonian regime. We show that when the Jacobian constant is fixed, a chaotic orbit in the Newtonian regime can be either chaotic or regular in the pseudo-Newtonian approach. As a general result, we find that most of the pseudo-Newtonian configurations are less stable than their Newtonian equivalent.

  11. Brain MR image segmentation using NAMS in pseudo-color.

    Science.gov (United States)

    Li, Hua; Chen, Chuanbo; Fang, Shaohong; Zhao, Shengrong

    2017-12-01

    Image segmentation plays a crucial role in various biomedical applications. In general, the segmentation of brain Magnetic Resonance (MR) images is mainly used to represent the image with several homogeneous regions instead of pixels for surgical analyzing and planning. This paper proposes a new approach for segmenting MR brain images by using pseudo-color based segmentation with Non-symmetry and Anti-packing Model with Squares (NAMS). First of all, the NAMS model is presented. The model can represent the image with sub-patterns to keep the image content and largely reduce the data redundancy. Second, the key idea is proposed that convert the original gray-scale brain MR image into a pseudo-colored image and then segment the pseudo-colored image with NAMS model. The pseudo-colored image can enhance the color contrast in different tissues in brain MR images, which can improve the precision of segmentation as well as directly visual perceptional distinction. Experimental results indicate that compared with other brain MR image segmentation methods, the proposed NAMS based pseudo-color segmentation method performs more excellent in not only segmenting precisely but also saving storage.

  12. BOILING WATER REACTOR WITH FEED WATER INJECTION NOZZLES

    Science.gov (United States)

    Treshow, M.

    1963-04-30

    This patent covers the use of injection nozzles for pumping water into the lower ends of reactor fuel tubes in which water is converted directly to steam. Pumping water through fuel tubes of this type of boiling water reactor increases its power. The injection nozzles decrease the size of pump needed, because the pump handles only the water going through the nozzles, additional water being sucked into the tubes by the nozzles independently of the pump from the exterior body of water in which the fuel tubes are immersed. The resulting movement of exterior water along the tubes holds down steam formation, and thus maintains the moderator effectiveness, of the exterior body of water. (AEC)

  13. Pool boiling of nanoparticle-modified surface with interlaced wettability

    KAUST Repository

    Hsu, Chin-Chi

    2012-01-01

    This study investigated the pool boiling heat transfer under heating surfaces with various interlaced wettability. Nano-silica particles were used as the coating element to vary the interlaced wettability of the surface. The experimental results revealed that when the wettability of a surface is uniform, the critical heat flux increases with the more wettable surface; however, when the wettability of a surface is modified interlacedly, regardless of whether the modified region becomes more hydrophilic or hydrophobic, the critical heat flux is consistently higher than that of the isotropic surface. In addition, this study observed that critical heat flux was higher when the contact angle difference between the plain surface and the modified region was smaller. © 2012 Hsu et al.

  14. Theoretical prediction method of subcooled flow boiling CHF

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Young Min; Chang, Soon Heung [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    A theoretical critical heat flux (CHF ) model, based on lateral bubble coalescence on the heated wall, is proposed to predict the subcooled flow boiling CHF in a uniformly heated vertical tube. The model is based on the concept that a single layer of bubbles contacted to the heated wall prevents a bulk liquid from reaching the wall at near CHF condition. Comparisons between the model predictions and experimental data result in satisfactory agreement within less than 9.73% root-mean-square error by the appropriate choice of the critical void fraction in the bubbly layer. The present model shows comparable performance with the CHF look-up table of Groeneveld et al.. 28 refs., 11 figs., 1 tab. (Author)

  15. Evaluation of correlations of flow boiling heat transfer of R22 in horizontal channels.

    Science.gov (United States)

    Zhou, Zhanru; Fang, Xiande; Li, Dingkun

    2013-01-01

    The calculation of two-phase flow boiling heat transfer of R22 in channels is required in a variety of applications, such as chemical process cooling systems, refrigeration, and air conditioning. A number of correlations for flow boiling heat transfer in channels have been proposed. This work evaluates the existing correlations for flow boiling heat transfer coefficient with 1669 experimental data points of flow boiling heat transfer of R22 collected from 18 published papers. The top two correlations for R22 are those of Liu and Winterton (1991) and Fang (2013), with the mean absolute deviation of 32.7% and 32.8%, respectively. More studies should be carried out to develop better ones. Effects of channel dimension and vapor quality on heat transfer are analyzed, and the results provide valuable information for further research in the correlation of two-phase flow boiling heat transfer of R22 in channels.

  16. Sensory quality and appropriateness of raw and boiled Jerusalem artichoke tubers (Helianthus tuberosus L.)

    DEFF Research Database (Denmark)

    Bach, Vibe; Kidmose, Ulla; Thybo, Anette

    2013-01-01

    BACKGROUND: The aim of the present study was to investigate the sensory attributes, dry matter and sugar content of five varieties of Jerusalem artichoke tubers and their relation to the appropriateness of the tubers for raw and boiled preparation. RESULTS: Sensory evaluation of raw and boiled...... Jerusalem artichoke tubers was performed by a trained sensory panel and a semi-trained consumer panel of 49 participants, who also evaluated the appropriateness of the tubers for raw and boiled preparation. The appropriateness of raw Jerusalem artichoke tubers was related to Jerusalem artichoke flavour...... attributes can be used as predictors of the appropriateness of Jerusalem artichoke tubers for raw and boiled consumption. Knowledge on the quality of raw and boiled Jerusalem artichoke tubers can be used to inform consumers on the right choice of rawmaterial and thereby increase the consumption...

  17. Nucleate boiling pressure drop in an annulus: Book 7

    Energy Technology Data Exchange (ETDEWEB)

    1992-11-01

    The application of the work described in this report is the production reactors at the Savannah River Site, and the context is nuclear reactor safety. The Loss of Coolant Accident (LOCA) scenario considered involves a double-ended break of a primary coolant pipe in the reactor. During a LOCA, the flow through portions of the reactor may reverse direction or be greatly reduced, depending upon the location of the break. The reduced flow rate of coolant (D{sub 2}O) through the fuel assembly channels of the reactor -- downflow in this situation -- can lead to boiling and to the potential for flow instabilities which may cause some of the fuel assembly channels to overheat and melt. That situation is to be avoided. The experimental approach is to provide a test annulus which simulates geometry, materials, and flow conditions in a Mark-22 fuel assembly (Coolant Channel 3) to the extent possible. The annulus has a full-scale geometry, and in fat uses SRL dummy hardware for the inner annulus wall in the ribbed geometry. The materials aluminum. The annulus is uniformly heated in the axial direction, but the circumferential heat flux can be varied to provide ``power tilt`` or asymmetric heating of the inner and outer annulus walls. The test facility uses H{sub 2}O rather than D{sub 2}O, but it includes the effects of dissolved helium gas present in the reactor. The key analysis approaches are: To compare the minima in the measured demand curves with analytical criteria, in particular the Saha-Zuber (1974) model; and to compare the pressure and temperature as a function of length in the annulus with an integral model for flow boiling in a heated channel. This document consists solely of tables of temperature measurements; minima, maxima, averages and standard deviations being measured.

  18. Nucleate boiling pressure drop in an annulus: Book 4

    Energy Technology Data Exchange (ETDEWEB)

    Block, J.A.; Crowley, C.; Dolan, F.X.; Sam, R.G.; Stoedefalke, B.H.

    1992-11-01

    The application of the work described in this report is the production reactors at the Savannah River Site, and the context is nuclear reactor safety. The Loss of Coolant Accident (LOCA) scenario considered involves a double-ended break of a primary coolant pipe in the reactor. During a LOCA, the flow through portions of the reactor may reverse direction or be greatly reduced, depending upon the location of the break. The reduced flow rate of coolant (D{sub 2}O) through the fuel assembly channels of the reactor -- downflow in this situation -- can lead to boiling and to the potential for flow instabilities which may cause some of the fuel assembly channels to overheat and melt. That situation is to be avoided. The experimental approach is to provide a test annulus which simulates geometry, materials, and flow conditions in a Mark-22 fuel assembly (Coolant Channel 3) to the extent possible. The annulus has a full-scale geometry, and in fat uses SRL dummy hardware for the inner annulus wall in the ribbed geometry. The materials aluminum. The annulus is uniformly heated in the axial direction, but the circumferential heat flux can be varied to provide ``power tilt`` or asymmetric heating of the inner and outer annulus walls. The test facility uses H{sub 2}O rather than D{sub 2}O, but it includes the effects of dissolved helium gas present in the reactor. The key analysis approaches are: To compare the minima in the measured demand curves with analytical criteria, in particular the Saha-Zuber (1974) model; and to compare the pressure and temperature as a function of length in the annulus with an integral model for flow boiling in a heated channel. This document consists of data plots and summary files of temperature measurements.

  19. Nucleate boiling pressure drop in an annulus: Book 3

    Energy Technology Data Exchange (ETDEWEB)

    Block, J.A.; Crowley, C.; Dolan, F.X.; Sam, R.G.; Stoedefalke, B.H.

    1992-11-01

    The application of the work described in this report is the production reactors at the Savannah River Site, and the context is nuclear reactor safety. The Loss of Coolant Accident (LOCA) scenario considered involves a double-ended break of a primary coolant pipe in the reactor. During a LOCA, the flow through portions of the reactor may reverse direction or be greatly reduced, depending upon the location of the break. The reduced flow rate of coolant (D{sub 2}O) through the fuel assembly channels of the reactor -- downflow in this situation -- can lead to boiling and to the potential for flow instabilities which may cause some of the fuel assembly channels to overheat and melt. That situation is to be avoided. The experimental approach is to provide a test annulus which simulates geometry, materials, and flow conditions in a Mark-22 fuel assembly (Coolant Channel 3) to the extent possible. The annulus has a full-scale geometry, and in fat uses SRL dummy hardware for the inner annulus wall in the ribbed geometry. The materials aluminum. The annulus is uniformly heated in the axial direction, but the circumferential heat flux can be varied to provide ``power tilt`` or asymmetric heating of the inner and outer annulus walls. The test facility uses H{sub 2}O rather than D{sub 2}O, but it includes the effects of dissolved helium gas present in the reactor. The key analysis approaches are: To compare the minima in the measured demand curves with analytical criteria, in particular the Saha-Zuber (1974) model; and to compare the pressure and temperature as a function of length in the annulus with an integral model for flow boiling in a heated channel. This document consists of data plots and summary files of temperature measurements.

  20. Liquid film dewetting induced by impulsive Joule heating

    Science.gov (United States)

    Mayer, H. C.; Krechetnikov, R.

    2017-09-01

    Motivated by the need for understanding the boiling processes in three-phase microscopic systems, the present work aims to uncover the physics of forced dewetting of a liquid film initially attached to a metal wire frame, which is heated with a rate up to O (108) K s-1 by discharging a capacitor impulsively. Depending on the corresponding heat flux ≤O (1011) J m-2 , there are several key dewetting regimes—no detachment, nonuniform detachment, and uniform detachment of a film—differentiated by boiling transitions in the film Plateau borders. Transitions between these regimes prove to occur, for various wire diameters and frame sizes, around the same values of the capacitor energy per unit wire volume. Also, an intrinsic transverse instability manifesting itself in the formation of fingers along the detached liquid film rim is discovered and analyzed in detail.

  1. Children's Understanding of Changes of State Involving the Gas State, Part 1: Boiling Water and the Particle Theory.

    Science.gov (United States)

    Johnson, Philip

    1998-01-01

    Explores the development of children's conception of a substance and reports the findings in relation to children's understanding of boiling water and particle ideas. Argues that boiling water should have a broad significance in the curriculum. Contains 23 references. (DDR)

  2. Diagnosis and Treatment of Pseudo-Class III Malocclusion

    Science.gov (United States)

    Reyes, Ariel; Serret, Luis; Peguero, Marcos; Tanaka, Orlando

    2014-01-01

    Pseudo-Class III malocclusion is characterized by the presence of an anterior crossbite due to a forward functional displacement of the mandible; in most cases, the maxillary incisors present some degree of retroclination, and the mandibular incisors are proclined. Various types of appliances have been described in the literature for the early treatment of pseudo-Class III malocclusion. The objectives of this paper are to demonstrate the importance of making the differential diagnosis between a skeletal and a pseudo-Class III malocclusion and to describe the correction of an anterior crossbite. The association of maxillary expansion and a 2 × 4 appliance can successfully be used to correct anterior crossbites. PMID:25525526

  3. Diagnosis and Treatment of Pseudo-Class III Malocclusion

    Directory of Open Access Journals (Sweden)

    Ariel Reyes

    2014-01-01

    Full Text Available Pseudo-Class III malocclusion is characterized by the presence of an anterior crossbite due to a forward functional displacement of the mandible; in most cases, the maxillary incisors present some degree of retroclination, and the mandibular incisors are proclined. Various types of appliances have been described in the literature for the early treatment of pseudo-Class III malocclusion. The objectives of this paper are to demonstrate the importance of making the differential diagnosis between a skeletal and a pseudo-Class III malocclusion and to describe the correction of an anterior crossbite. The association of maxillary expansion and a 2 × 4 appliance can successfully be used to correct anterior crossbites.

  4. Occlusal rehabilitation of pseudo-class III patient.

    Science.gov (United States)

    Cardoso, Antônio Carlos; Ferreira, Cimara Fortes; Oderich, Elisa; Pedroso, Moira Leão; Wicks, Russell

    2015-01-01

    To treat a patient with anterior crossbite, the clinician should first assess if it is a genuine class III or a pseudo-class III malocclusion. Cephalometric analysis is important; however, registering a patient's centric relation (CR) is simple, quick, and costless and can play a decisive role in a differential diagnosis for this type of patient profile. This clinical report depicts a patient clinically diagnosed as class III. After mandible manipulation in CR, it was noted that the patient in question was a pseudo-class III. The treatment was based on the pseudo-class III diagnosis. Therefore, the patient was rehabilitated by occlusal adjustments and conventional and implant-supported prostheses and without the need for invasive orthognathic surgery. © 2014 by the American College of Prosthodontists.

  5. Pseudo-Glassification Material for G-Demption

    Energy Technology Data Exchange (ETDEWEB)

    Casella, Andrew M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Buck, Edgar C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gates, Robert O. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Riley, Brian J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-09-01

    G-Demption, LLC has requested that PPNL provide design input for a “pseudo-glassification” process associated with their proposed technology for generating gamma irradiation stations from used nuclear fuel. The irradiation design currently consists of an aluminum enclosure designed to allow for proper encapsulation of and heat flow from a used fuel rod while minimally impacting the streaming of gamma rays from the fuel. In order to make their design more robust, G-Demption is investigating the benefits of backfilling this aluminum enclosure with a setting material once the used fuel rod is properly placed. This process has been initially referred to as “pseudo-glassification”, and strives not to impact heat transport or gamma streaming from the used fuel rod while providing increased fuel rod protection and fission gas retention. PNNL has compiled an internal material evaluation and discussion for the “pseudo-glassification” process in this report.

  6. Pseudo-periodic maps and degeneration of Riemann surfaces

    CERN Document Server

    Matsumoto, Yukio

    2011-01-01

    The first part of the book studies pseudo-periodic maps of a closed surface of genus greater than or equal to two. This class of homeomorphisms was originally introduced by J. Nielsen in 1944 as an extension of periodic maps. In this book, the conjugacy classes of the (chiral) pseudo-periodic mapping classes are completely classified, and Nielsen’s incomplete classification is corrected. The second part applies the results of the first part to the topology of degeneration of Riemann surfaces. It is shown that the set of topological types of all the singular fibers appearing in one-parameter holomorphic families of Riemann surfaces is in a bijective correspondence with the set of conjugacy classes of the pseudo-periodic maps of negative twists. The correspondence is given by the topological monodromy.

  7. Optimal Base Encodings for Pseudo-Boolean Constraints

    CERN Document Server

    Codish, Michael; Fuhs, Carsten; Schneider-Kamp, Peter

    2010-01-01

    This paper formalizes the "optimal base problem", presents an algorithm to solve it, and describes its application to the encoding of Pseudo-Boolean constraints to SAT. We demonstrate the impact of integrating our algorithm within the Pseudo-Boolean constraint solver MiniSAT+. Experimentation indicates that our algorithm scales to consider bases involving numbers up to 1,000,000, improving on the restriction in MiniSAT+ to prime numbers up to 17. We show that, while for many examples primes up to 17 do suffice, encoding with respect to arbitrary bases improves the subsequent SAT solving time considerably.

  8. Intestinal pseudo-obstruction: An important diagnostic challenge

    Directory of Open Access Journals (Sweden)

    Carmen Salvador-Coloma

    2015-09-01

    Full Text Available We present the case of a 72-year-old patient admitted on various occasions with symptoms of intestinal pseudo-obstruction. Extensive diagnostic tests eventually found that the patient had small-cell lung cancer associated with high anti-HU antibody titres, which pointed to a probable paraneoplastic intestinal obstruction syndrome associated with small-cell lung cancer. A paraneoplastic syndrome causing abnormal changes in gastrointestinal motility can be the first signs of small cell lung cancer. These syndromes improve with treatment of the underlying disease, as seen in our patient, who stopped having episodes of intestinal pseudo-obstruction after administration of chemotherapy.

  9. Enhancing pseudo-telepathy in the magic square game.

    Directory of Open Access Journals (Sweden)

    Lukasz Pawela

    Full Text Available We study the possibility of reversing an action of a quantum channel. Our principal objective is to find a specific channel that reverses as accurately as possible an action of a given quantum channel. To achieve this goal we use semidefinite programming. We show the benefits of our method using the quantum pseudo-telepathy Magic Square game with noise. Our strategy is to move the pseudo-telepathy region to higher noise values. We show that it is possible to reverse the action of a noise channel using semidefinite programming.

  10. Enhancing pseudo-telepathy in the magic square game.

    Science.gov (United States)

    Pawela, Lukasz; Gawron, Piotr; Puchała, Zbigniew; Sładkowski, Jan

    2013-01-01

    We study the possibility of reversing an action of a quantum channel. Our principal objective is to find a specific channel that reverses as accurately as possible an action of a given quantum channel. To achieve this goal we use semidefinite programming. We show the benefits of our method using the quantum pseudo-telepathy Magic Square game with noise. Our strategy is to move the pseudo-telepathy region to higher noise values. We show that it is possible to reverse the action of a noise channel using semidefinite programming.

  11. Signed Distance Computation using the Angle Weighted Pseudo-normal

    DEFF Research Database (Denmark)

    Bærentzen, Jakob Andreas; Aanæs, Henrik

    2005-01-01

    , the surface is not \\$C\\^1\\$ continuous, hence, the normal is undefined at these loci. In this paper, we undertake to show that the angle weighted pseudo-normal (originally proposed by Thürmer and Wüthrich and independently by Sequin) has the important property that it allows us to discriminate between points...... of the distance computation. Moreover, it provides an additional argument in favour of the angle weighted pseudo-normals being the natural extension of the face normals. Apart from the theoretical results, we also propose a simple and efficient algorithm for computing the signed distance to a closed \\$C\\^0\\$ mesh...

  12. True versus Pseudo-Intestinal Malrotation: Case Series and Review.

    Science.gov (United States)

    Khara, Harshit S; Kothari, Shivangi T; Gruss, Claudia B; Langnas, Alan; Schafer, Daniel F; McCashland, Timothy M

    2013-10-01

    Intestinal malrotation is an anomaly of fetal intestinal rotation that can present with symptoms after birth or in early childhood, but is rarely diagnosed in adults. Patients who have symptomatic presentations require surgery. Other entities may mimic intestinal malrotation and respond to non-surgical management. We present 2 adult cases with the radiological diagnosis of intestinal malrotation: one with true malrotation presenting as a duodenal mass, and another with "pseudo-malrotation" due to altered anatomy. These cases illustrate the importance of recognizing and differentiating these rare adult presentations of true malrotation from "pseudo-malrotation" in regards to their acute management.

  13. "Divine water" in the alchemical writings of pseudo-Democritus.

    Science.gov (United States)

    Martelli, Matteo

    2009-03-01

    The name of the chemical solution (divine water) or (sulfur water) is characterised by semantic ambiguity: the term theion means both "divine" and "sulfur," and Greek alchemists frequently play on this polysemy. This article analyses the use of this and similar expressions in the writings of pseudo-Democritus from both a technical and a philological point of view. A fragment preserved by the alchemists Moses and Synesius shows that pseudo-Democritus knows two different kinds of this "water," the second of which recalls a recipe found in the chemical Leiden Papyrus, and that the composition of the substance determines the form of its name.

  14. Perturbation of sectorial projections of elliptic pseudo-differential operators

    DEFF Research Database (Denmark)

    Booss-Bavnbek, Bernhelm; Chen, Guoyuan; Lesch, Matthias

    2012-01-01

    Over a closed manifold, we consider the sectorial projection of an elliptic pseudo-differential operator A of positive order with two rays of minimal growth. We showthat it depends continuously on A when the space of pseudo-differential operators is equipped with a certain topology whichwe...... explicitly describe. Our main application deals with a continuous curve of arbitrary first order linear elliptic differential operators over a compact manifold with boundary. Under the additional assumption of the weak inner unique continuation property, we derive the continuity of a related curve...

  15. Study of pseudo soldering based on eddy current pulsed thermography

    Science.gov (United States)

    Zhou, Xiuyun; Xue, Yun; Chen, Yaqiu; Lu, Xiaochuan; Liu, Zhen

    2017-09-01

    Pseudo soldering defects can break the electrical and mechanical connection between components and the print circuit board and eventually cause failure of the whole electronic equipment. In this letter, the eddy current pulsed thermography (ECPT) method was used for defect inspection of small-sized solder joints. The identification of defects of solder joints is based on the heat transfer between various component structures. The experimental results indicated that the ECPT method can be effectively used for defect detection and location of the solder joints. In addition, it can distinguish different degrees of pseudo soldering.

  16. 78 FR 35990 - All Operating Boiling-Water Reactor Licensees With Mark I And Mark II Containments; Docket Nos...

    Science.gov (United States)

    2013-06-14

    ... COMMISSION All Operating Boiling-Water Reactor Licensees With Mark I And Mark II Containments; Docket Nos... Licensees operate boiling-water reactors (BWRs) with Mark I and Mark II containment designs. II. The events... Boiling Water Reactors with Mark I and Mark II Containments'' (November 26, 2012). Option 2 in SECY-12...

  17. 78 FR 63516 - Initial Test Program of Emergency Core Cooling Systems for New Boiling-Water Reactors

    Science.gov (United States)

    2013-10-24

    ... COMMISSION Initial Test Program of Emergency Core Cooling Systems for New Boiling-Water Reactors AGENCY... Cooling Systems for New Boiling-Water Reactors.'' This RG describes testing methods the NRC staff...)-1277, ``Initial Test Program of Emergency Core Cooling Systems for Boiling-Water Reactors.'' DG-1277...

  18. 75 FR 26967 - Guidance for Industry: Use of Water by Food Manufacturers in Areas Subject to a Boil-Water...

    Science.gov (United States)

    2010-05-13

    ... Areas Subject to a Boil-Water Advisory; Availability AGENCY: Food and Drug Administration, HHS. ACTION... entitled ``Guidance for Industry: Use of Water by Food Manufacturers in Areas Subject to a Boil-Water Advisory.'' This guidance is intended to advise food manufacturers that once a boil-water advisory has been...

  19. An assessment of boiling as a method of household water treatment in South India.

    Science.gov (United States)

    Juran, Luke; MacDonald, Morgan C

    2014-12-01

    This article scrutinizes the boiling of water in Tamil Nadu and Puducherry, India. Boiling, as it is commonly practiced, improves water quality, but its full potential is not being realized. Thus, the objective is to refine the method in practice, promote acceptability, and foster the scalability of boiling and household water treatment (HWT) writ large. The study is based on bacteriological samples from 300 households and 80 public standposts, 14 focus group discussions (FGDs), and 74 household interviews. Collectively, the data fashion both an empirical and ethnographic understanding of boiling. The rate and efficacy of boiling, barriers to and caveats of its adoption, and recommendations for augmenting its practice are detailed. While boiling is scientifically proven to eliminate bacteria, data demonstrate that pragmatics inhibit their total destruction. Furthermore, data and the literature indicate that a range of cultural, economic, and ancillary health factors challenge the uptake of boiling. Fieldwork and resultant knowledge arrive at strategies for overcoming these impediments. The article concludes with recommendations for selecting, introducing, and scaling up HWT mechanisms. A place-based approach that can be sustained over the long-term is espoused, and prolonged exposure by the interveners coupled with meaningful participation of the target population is essential.

  20. Microbiologic effectiveness of boiling and safe water storage in South Sulawesi, Indonesia.

    Science.gov (United States)

    Sodha, Samir V; Menon, M; Trivedi, K; Ati, A; Figueroa, M E; Ainslie, R; Wannemuehler, K; Quick, R

    2011-09-01

    In Indonesia, where diarrhea remains a major cause of mortality among children boiling of drinking water. We assessed the impact of boiling on water quality in South Sulawesi. We surveyed randomly selected households with at least one child water samples for Escherichia coli contamination. Among 242 households, 96% of source and 51% of stored water samples yielded E. coli. Unboiled water samples, obtained from 15% of households, were more likely to yield E. coli than boiled samples [prevalence ratios (PR) = 2.0, 95% confidence interval (CI) 1.7-2.5]. Water stored in wide-mouthed (PR = 1.4, 95% CI = 1.1-1.8) or uncovered (PR = 1.8, 95% CI = 1.3-2.4) containers, or observed to be touched by the respondent's hands (PR = 1.6, 95% CI = 1.3-2.1) was more likely to yield E. coli. A multivariable model showed that households that did not boil water were more likely to have contaminated stored water than households that did boil water (PR = 1.9, 95% CI = 1.5-2.3). Although this study demonstrated the effectiveness of boiling in reducing contamination, overall impact on water quality was suboptimal. Future studies are needed to identify factors behind the success of boiling water in Indonesia to inform efforts to scale up other effective water treatment practices.

  1. Hypergravity to Explore the Role of Buoyancy in Boiling in Porous Media

    Science.gov (United States)

    Lioumbas, John S.; Krause, Jutta; Karapantsios, Thodoris D.

    2013-02-01

    Boiling in porous media is an active topic of research since it is associated with various applications, e.g. microelectronics cooling, wetted porous media as thermal barriers, food frying. Theoretical expressions customary scale boiling heat and mass transfer rates with the value of gravitational acceleration. Information obtained at low gravity conditions show a deviation from the above scaling law but refers exclusively to non-porous substrates. In addition, the role of buoyancy in boiling at varying gravitational levels (i.e. from microgravity—important to satellites and future Lunar and Martial missions, to high-g body forces—associated with fast aerial maneuvers) is still unknown since most experiments were conducted over a limited range of g-value. The present work aims at providing evidence regarding boiling in porous media over a broad range of hypergravity values. For this, a special device has been constructed for studying boiling inside porous media in the Large Diameter Centrifuge (LDC at ESA/ESTEC). LDC offers the unique opportunity to cancel the shear stresses and study only the effect of increased normal forces on boiling in porous media. The device permits measurement of the temperature field beneath the surface of the porous material and video recordings of bubble activity over the free surface of the porous material. The preliminary results presented from experiments conducted at terrestrial and hypergravity conditions, reveal for the first time the influence of increased levels of gravity on boiling in porous media.

  2. Thin Films

    Directory of Open Access Journals (Sweden)

    M. Benmouss

    2003-01-01

    the optical absorption are consistent with the film color changes. Finally, the optical and electrochromic properties of the films prepared by this method are compared with those of our sputtered films already studied and with other works.

  3. Models and Stability Analysis of Boiling Water Reactors

    Energy Technology Data Exchange (ETDEWEB)

    John Dorning

    2002-04-15

    We have studied the nuclear-coupled thermal-hydraulic stability of boiling water reactors (BWRs) using a model that includes: space-time modal neutron kinetics based on spatial w-modes; single- and two-phase flow in parallel boiling channels; fuel rod heat conduction dynamics; and a simple model of the recirculation loop. The BR model is represented by a set of time-dependent nonlinear ordinary differential equations, and is studied as a dynamical system using the modern bifurcation theory and nonlinear dynamical systems analysis. We first determine the stability boundary (SB) - or Hopf bifurcation set- in the most relevant parameter plane, the inlet-subcooling-number/external-pressure-drop plane, for a fixed control rod induced external reactivity equal to the 100% rod line value; then we transform the SB to the practical power-flow map used by BWR operating engineers and regulatory agencies. Using this SB, we show that the normal operating point at 100% power is very stable, that stability of points on the 100% rod line decreases as the flow rate is reduced, and that operating points in the low-flow/high-power region are least stable. We also determine the SB that results when the modal kinetics is replaced by simple point reactor kinetics, and we thereby show that the first harmonic mode does not have a significant effect on the SB. However, we later show that it nevertheless has a significant effect on stability because it affects the basin of attraction of stable operating points. Using numerical simulations we show that, in the important low-flow/high-power region, the Hopf bifurcation that occurs as the SB is crossed is subcritical; hence, growing oscillations can result following small finite perturbations of stable steady-states on the 100% rod line at points in the low-flow/high-power region. Numerical simulations are also performed to calculate the decay ratios (DRs) and frequencies of oscillations for various points on the 100% rod line. It is

  4. Fermionic coherent states for pseudo-Hermitian two-level systems

    Energy Technology Data Exchange (ETDEWEB)

    Cherbal, O [Physical Faculty, Theoretical Physics Lab, USTHB, BP 32 El-Alia, Bab Ezzouar, 16111 Algiers (Algeria); Drir, M [Physical Faculty, Theoretical Physics Lab, USTHB, BP 32 El-Alia, Bab Ezzouar, 16111 Algiers (Algeria); Maamache, M [Laboratoire de Physique Quantique et Systemes Dynamiques, Department of Physics, Setif University, Setif 19000 (Algeria); Trifonov, D A [Institute of Nuclear Research, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria)

    2007-02-23

    We introduce creation and annihilation operators of pseudo-Hermitian fermions for two-level systems described by a pseudo-Hermitian Hamiltonian with real eigenvalues. This allows the generalization of the fermionic coherent states approach to such systems. Pseudo-fermionic coherent states are constructed as eigenstates of two pseudo-fermion annihilation operators. These coherent states form a bi-normal and bi-overcomplete system, and their evolution governed by the pseudo-Hermitian Hamiltonian is temporally stable. In terms of the introduced pseudo-fermion operators, the two-level system Hamiltonian takes a factorized form similar to that of a harmonic oscillator.

  5. Pseudo-observations for competing risks with covariate dependent censoring

    DEFF Research Database (Denmark)

    Binder, Nadine; Gerds, Thomas A; Andersen, Per Kragh

    2014-01-01

    that the probability of not being lost to follow-up (un-censored) is independent of the covariates. Modified pseudo-values are proposed which rely on a correctly specified regression model for the censoring times. Bias and efficiency of these methods are compared in a simulation study. Further illustration...

  6. Probing pseudo-Dirac neutrino through detection of neutrino ...

    Indian Academy of Sciences (India)

    The expected secondary muons from such neutrinos that can be detected by a kilometer scale detector such as ICECUBE is calculated and compared with the same in the case of mass-flavour oscillations and for no oscillation cases. The calculated muon yields indicate that to probe such small pseudo-Dirac splittings one ...

  7. Probing pseudo-Dirac neutrino through detection of neutrino ...

    Indian Academy of Sciences (India)

    ~EeV for such neutrinos invoke the likelihood to probe very small pseudo-Dirac splittings. The expected secondary muons from such neutrinos that can be detected by a kilometer scale detector such as ICECUBE is calculated and compared with the same in the case of mass-flavour oscillations and for no oscillation cases.

  8. Production of bioethanol using agricultural waste: banana pseudo stem

    Directory of Open Access Journals (Sweden)

    Snehal Ingale

    2014-09-01

    Full Text Available India is amongst the largest banana (Musa acuminata producing countries and thus banana pseudo stem is commonly available agricultural waste to be used as lignocellulosic substrate. Present study focuses on exploitation of banana pseudo stem as a source for bioethanol production from the sugars released due to different chemical and biological pretreatments. Two fungal strains Aspergillus ellipticus and Aspergillus fumigatus reported to be producing cellulolytic enzymes on sugarcane bagasse were used under co-culture fermentation on banana pseudo stem to degrade holocellulose and facilitate maximum release of reducing sugars. The hydrolysate obtained after alkali and microbial treatments was fermented by Saccharomyces cerevisiae NCIM 3570 to produce ethanol. Fermentation of cellulosic hydrolysate (4.1 g% gave maximum ethanol (17.1 g/L with yield (84% and productivity (0.024 g%/h after 72 h. Some critical aspects of fungal pretreatment for saccharification of cellulosic substrate using A. ellipticus and A. fumigatus for ethanol production by S. cerevisiae NCIM 3570 have been explored in this study. It was observed that pretreated banana pseudo stem can be economically utilized as a cheaper substrate for ethanol production.

  9. Over het specifieke- en pseudo cholinesterasegehalte bij enige ziekten

    NARCIS (Netherlands)

    Strater, Hans

    1948-01-01

    De monographie van Libbrecht,,De arteriele hypertoniën"was voor ons de aanleiding om een onderzoek te doen over het specifieke en pseudo-cholinesterase bij verschillende vormen van hypertensie, myasthenie en asthma bronchiale. ... Zie: Samenvatting

  10. Tropomyosin Ser-283 pseudo-phosphorylation slows myofibril relaxation.

    Science.gov (United States)

    Nixon, Benjamin R; Liu, Bin; Scellini, Beatrice; Tesi, Chiara; Piroddi, Nicoletta; Ogut, Ozgur; Solaro, R John; Ziolo, Mark T; Janssen, Paul M L; Davis, Jonathan P; Poggesi, Corrado; Biesiadecki, Brandon J

    2013-07-01

    Tropomyosin (Tm) is a central protein in the Ca(2+) regulation of striated muscle. The αTm isoform undergoes phosphorylation at serine residue 283. While the biochemical and steady-state muscle function of muscle purified Tm phosphorylation have been explored, the effects of Tm phosphorylation on the dynamic properties of muscle contraction and relaxation are unknown. To investigate the kinetic regulatory role of αTm phosphorylation we expressed and purified native N-terminal acetylated Ser-283 wild-type, S283A phosphorylation null and S283D pseudo-phosphorylation Tm mutants in insect cells. Purified Tm's regulate thin filaments similar to that reported for muscle purified Tm. Steady-state Ca(2+) binding to troponin C (TnC) in reconstituted thin filaments did not differ between the 3 Tm's, however disassociation of Ca(2+) from filaments containing pseudo-phosphorylated Tm was slowed compared to wild-type Tm. Replacement of pseudo-phosphorylated Tm into myofibrils similarly prolonged the slow phase of relaxation and decreased the rate of the fast phase without altering activation kinetics. These data demonstrate that Tm pseudo-phosphorylation slows deactivation of the thin filament and muscle force relaxation dynamics in the absence of dynamic and steady-state effects on muscle activation. This supports a role for Tm as a key protein in the regulation of muscle relaxation dynamics. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Pseudo-Riemannian geometry, [delta]-invariants and applications

    CERN Document Server

    Chen, Bang-Yen

    2011-01-01

    The first part of this book provides a self-contained and accessible introduction to the subject in the general setting of pseudo-Riemannian manifolds and their non-degenerate submanifolds, only assuming from the reader some basic knowledge about manifold

  12. Production of bioethanol using agricultural waste: banana pseudo stem.

    Science.gov (United States)

    Ingale, Snehal; Joshi, Sanket J; Gupte, Akshaya

    2014-01-01

    India is amongst the largest banana (Musa acuminata) producing countries and thus banana pseudo stem is commonly available agricultural waste to be used as lignocellulosic substrate. Present study focuses on exploitation of banana pseudo stem as a source for bioethanol production from the sugars released due to different chemical and biological pretreatments. Two fungal strains Aspergillus ellipticus and Aspergillus fumigatus reported to be producing cellulolytic enzymes on sugarcane bagasse were used under co-culture fermentation on banana pseudo stem to degrade holocellulose and facilitate maximum release of reducing sugars. The hydrolysate obtained after alkali and microbial treatments was fermented by Saccharomyces cerevisiae NCIM 3570 to produce ethanol. Fermentation of cellulosic hydrolysate (4.1 g%) gave maximum ethanol (17.1 g/L) with yield (84%) and productivity (0.024 g%/h) after 72 h. Some critical aspects of fungal pretreatment for saccharification of cellulosic substrate using A. ellipticus and A. fumigatus for ethanol production by S. cerevisiae NCIM 3570 have been explored in this study. It was observed that pretreated banana pseudo stem can be economically utilized as a cheaper substrate for ethanol production.

  13. Pseudo-homophony in non-native listening

    NARCIS (Netherlands)

    Cutler, A.; Otake, T.

    2004-01-01

    Pseudo-homophony may result when non-native listeners cannot distinguish phonemic contrasts. Thus Dutch listeners have difficulty distinguishing the vowels of English cattle versus kettle, because this contrast is subsumed by a single Dutch vowel category; in consequence, both words may be activated

  14. Empirical pseudo-potential studies on electronic structure of ...

    Indian Academy of Sciences (India)

    Wintec

    and the lowest unoccupied molecular orbital (LUMO) as a function of shape and size of the quantum dots. Our studies explain the ... Keywords. Quantum dots; empirical pseudo-potential; electronic structure; HOMO–LUMO gap. 1. Introduction ...... both the finite and infinite well EMA breaks down and introduces significant ...

  15. Random matrix theory for pseudo-Hermitian systems: Cyclic blocks

    Indian Academy of Sciences (India)

    tems, and, for Hamiltonians that break parity P and time-reversal invariance T. In an attempt to understand the ... Keywords. Random matrices; circulants; quantum chaos; PT symmetry; pseudo-. Hermiticity. ... local fluctuation properties of complex quantum systems have universal properties, independent of the details of the ...

  16. Status asthmaticus with pseudo-dextrocardia, complicated by ...

    African Journals Online (AJOL)

    A chest x-ray revealed pseudo-dextrocardia and air trapping (A). She did not respond to inhaled bronchodilator therapy. Intravenous hydrocortisone and magnesium sulphate were administered. The patient deteriorated and was subsequently ventilated and intravenous aminophylline initiated. After intubation and ventilation ...

  17. To avoid operating on pseudo tumoral pulmonary infarctions ...

    African Journals Online (AJOL)

    Pulmonary infarction usually appears as a hump-shaped triangular opacity with its base applied to a pleural surface. In some cases, pulmonary infarctions may appear as a pseudo tumoral opacity mimicking lung cancer. Thoracotomy could be prevented by repeating CT scan in properly selected patients. Pan African ...

  18. Contextuality in multipartite pseudo-telepathy graph games

    OpenAIRE

    Anshu, Anurag; Hoyer, Peter; Mhalla, Mehdi; Perdrix, Simon

    2016-01-01

    Analyzing pseudo-telepathy graph games, we propose a way to build contextuality scenarios exhibiting the quantum supremacy using graph states. We consider the combinatorial structures that generate equivalent scenarios. We introduce a new tool called multipartiteness width to investigate which scenarios are harder to decompose and show that there exist graphs generating scenarios with a linear multipartiteness width.

  19. Pseudo-nitzschia blooms and physical oceanography off ...

    African Journals Online (AJOL)

    During three surveys conducted in early summer 1996, 1997 and 1998, high concentrations of. Pseudo-nitzschia spp. (values of up to 106 cells.l-1, but generally <105 cells.l-1) were present. P. pungens was dominant in 1996, whereas P. pseudodelicatissima was most abundant in 1997 and 1998. A. catenella was rare and ...

  20. A pseudo Lindley distribution and its application | Zeghdoudi | Afrika ...

    African Journals Online (AJOL)

    In this paper, we introduce a new distribution named as the Pseudo Lindley Distribution (PsLD) as a generalization of the Lindley distribution (LD). A full and detailed description are provided in terms of moments, cumulates, characteristic function, failure, rate function, stochastic ordering, distributions of sums, and ...

  1. Mann iteration with errors for strictly pseudo-contractive mappings ...

    African Journals Online (AJOL)

    It is well known that any fixed point of a Lipschitzian strictly pseudo-contractive self mapping of a nonempty closed convex and bounded subset K of a Banach space X is unique [6] and may be norm approximated by an iterative procedure. In this paper, we show that Mann iteration with errors can be used to approximate the ...

  2. Random matrix theory for pseudo-Hermitian systems: Cyclic blocks

    Indian Academy of Sciences (India)

    We discuss the relevance of random matrix theory for pseudo-Hermitian systems, and, for Hamiltonians that break parity and time-reversal invariance . In an attempt to understand the random Ising model, we present the treatment of cyclic asymmetric matrices with blocks and show that the nearest-neighbour spacing ...

  3. Optimalisasi Desain Parameter Lapangan Untuk Data Resistivitas Pseudo 3D

    Directory of Open Access Journals (Sweden)

    . Makhrani

    2013-05-01

    Full Text Available Penelitian yang berjudul Optimalisasi Desain Parameter Lapangan Untuk Data Resistivitas Pseudo 3D dilakukan dengan tujuan memprediksi model geologi dan mengestimasi parameter-parameter geofisika, menentukan sensitivitas dari konfigurasi Wenner-Schlumberger dan Wenner dalam mendeteksi anomali, membuat Pseudo 3D dari profil 2D serta meningkatkan kemampuan dalam memilih parameter survei  yang optimal  berdasarkan perbandingan kekuatan signal yang diharapkan dan kharakteristik dari bising (noise. Proses pengambilan data dilakukan dengan menggunakan metode geolistrik konfigurasi Wenner-Schlumberger dan konfigurasi Wenner. Pengolahan data geolistrik resistivitas dalam penelitian ini diawali dengan pengolahan data sintetik hasil forward modeling. Data ini dapat dijadikan sebagai data masukan pada perangkat lunak Surfer 9 untuk menggambarkan profil 2D. Seluruh hasil inversi dalam bentuk profil 2D akan digabungkan sehingga menjadi profil pseudo 3D, proses ini akan dilakukan dengan menggunakan perangkat lunak Matlab R2008a. Kedua konfigurasi yang digunakan dalam penelitian ini masing-masing memiliki keunggulan dan kelemahan dalam hal sensitivitas, baik konfigurasi Wenner-Schlumberger maupun konfigurasi Wenner. Meskipun kedua konfigurasi mendeteksi anomali yang dibuat, namun konfigurasi Wenner-Schlumberger lebih menonjolkan anomali, baik pada data sintetik maupun pada hasil pengukuran. Selain itu, pembuatan pseudo 3D dari profil 2D dapat membantu dalam menginterpretasi data pada lintasan yang saling berpotongan.

  4. Prediction of survival with alternative modeling techniques using pseudo values

    NARCIS (Netherlands)

    T. van der Ploeg (Tjeerd); F.R. Datema (Frank); R.J. Baatenburg de Jong (Robert Jan); E.W. Steyerberg (Ewout)

    2014-01-01

    textabstractBackground: The use of alternative modeling techniques for predicting patient survival is complicated by the fact that some alternative techniques cannot readily deal with censoring, which is essential for analyzing survival data. In the current study, we aimed to demonstrate that pseudo

  5. Cryptography, statistics and pseudo-randomness (Part 1)

    NARCIS (Netherlands)

    Brands, S.; Gill, R.D.

    1995-01-01

    In the classical approach to pseudo-random number generators, a generator is considered to perform well if its output sequences pass a battery of statistical tests that has become standard. In recent years, it has turned out that this approach is not satisfactory. Many generators have turned out to

  6. Twisted surfaces in the Pseudo-Galilean space

    Directory of Open Access Journals (Sweden)

    Ahmet Kazan

    2017-10-01

    Full Text Available In this paper, we construct the twisted surfaces according to the supporting plane and type of rotations in pseudo-Galilean space G13. Also, we find the Gaussian curvatures and mean curvatures of the different types of these twisted surfaces and draw some figures for these twisted surfaces.

  7. Pseudo-affinity chromatography of rumen microbial cellulase on ...

    African Journals Online (AJOL)

    Pseudo affinity adsorption of bioproducts on Sepharose-cibacron blue F3-GA was subjected to rumen microbial enzyme evaluation through batch binding and column chromatography of cellulase. The results showed that homogenizing method had better performance in the release of enzyme, so that the amount of enzyme ...

  8. Empirical pseudo-potential studies on electronic structure of ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 31; Issue 3. Empirical pseudo-potential studies on electronic structure of semiconducting quantum dots. Anjali Kshirsagar Neelesh ... Theoretical investigations of electronic structure of quantum dots is of current interest in nanophase materials. Empirical theories such ...

  9. Pseudo-Meig's Syndrome associated with huge Uterine Leiomyoma ...

    African Journals Online (AJOL)

    Background: Pseudo-Meigs syndrome consists of pleural effusion, ascites, and benign tumors of the ovary other than fibromas. These benign tumors include the tumors of fallopian tube or uterus, mature teratomas, struma ovarii, and ovarian leiomyomas. In a postmenopausal woman presence of complex pelvic mass, ...

  10. Pseudo-cryptanalysis of the Original Blue Midnight Wish

    DEFF Research Database (Denmark)

    Thomsen, Søren Steffen

    2010-01-01

    cryptanalysis on the original version of BMW, as submitted to the SHA-3 competition in October 2008. The attacks described are (near-)collision, preimage and second preimage attacks on the BMW compression function. These attacks can also be described as pseudo-attacks on the full hash function, i.e., as attacks...

  11. Computing the Visibility Graph via Pseudo-triangulations

    NARCIS (Netherlands)

    Pocchiola, Michel; Vegter, Gert

    1995-01-01

    We show that the k free bitangents of a collection of n pairwise disjoint convex plane sets can be computed in time O(k + n log n) and O(n) working space. The algorithm uses only one advanced data structure, namely a splittable queue. We introduce (weakly) greedy pseudo-triangulations, whose

  12. Neuropathie optique compressive secondaire à une pseudo-tumeur ...

    African Journals Online (AJOL)

    Neuropathie optique compressive secondaire à une pseudo-tumeur inflammatoire. Wafa Ammari, Olfa Berriche, Olfa Berriche. Abstract. La neuropathie optique regroupe l'ensemble des lésions du nerf optique. Le diagnostic est habituellement clinique: diminution de l'acuité visuelle, altération de la vision des couleurs, ...

  13. Critical heat flux for free convection boiling in thin rectangular channels

    Science.gov (United States)

    Cheng, Lap Y.; Tichler, P. R.

    A review of the experimental data on free convection boiling critical heat flux (CHF) in vertical rectangular channels reveals three mechanisms of burnout. They are the pool boiling limit, the circulation limit, and the flooding limit associated with a transition in flow regime from churn to annular flow. The dominance of a particular mechanism depends on the dimensions of the channel. Analytical models were developed for each free convection boiling limit. Limited agreement with data is observed. A CHF correlation, which is valid for a wide range of gap sizes, was constructed from the CHF's calculated according to the three mechanisms of burnout.

  14. An investigation into the influence of different parameters on the onset of boiling in minichannels

    OpenAIRE

    Piasecka Magdalena

    2013-01-01

    The paper presents experimental studies on boiling heat transfer in rectangular minichannels. The investigations focus on the transition from single phase forced convection to nucleate boiling, i.e., in the zone of boiling incipience. The experiment has been carried out with FC-72, R-123 and R-11 at the Reynolds number below 4700, corresponding to mass flow rate range 95-710 kg/(m s). The main part of the test section is a minichannel of pre-set depth from 0.7 to 2 mm and width (20, 40 and 60...

  15. Kandlikar third number map for flow boiling in micro-channels and micro-gravity

    Directory of Open Access Journals (Sweden)

    Awad M.M.

    2015-01-01

    Full Text Available As an extension of the recent work of Baldassari and Marengo (Baldassari C., Marengo M., Flow Boiling in Microchannels and Microgravity, Progress in Energy and Combustion Science 39 (2013 1, pp. 1-36, this note presents Kandlikar third number (K3 map for flow boiling in microchannels and microgravity. Using several data points available in the literature, Kandlikar third number (K3 map was plotted versus the hydraulic diameter (dh as the characteristic dimension for flow boiling in microchannels and microgravity. The ranges of the Kandlikar third number (K3, calculated using the hydraulic diameter (dh, are presented.

  16. Pseudo-obstrucción intestinal crónica Chronic intestinal pseudo-obstruction

    Directory of Open Access Journals (Sweden)

    M. T. Muñoz

    2007-02-01

    Full Text Available El síndrome de pseudo-obstrucción intestinal crónica se caracteriza por la presencia de cuadros clínicos recidivantes que simulan una obstrucción intestinal pero en ausencia de proceso obstructivo anatómico. Es poco frecuente pero determina una alta morbilidad. Se origina como consecuencia de una alteración de la motilidad intestinal que no puede hacer progresar su contenido debido a la afectación de su componente muscular, neurológico o de ambos. Son más frecuentes los casos secundarios a un proceso sistémico pero cada vez se describen más cuadros debidos a la afectación primaria de dichos componentes. El desarrollo de técnicas manométricas e histológicas más específicas ha permitido aclarar la patogenia de algunos de estos síndromes, entre los que se incluyen las manifestaciones paraneoplásicas y las enfermedades mitocondriales. La expresión clínica es variable y depende de la causa y de la localización y extensión de la afectación. El diagnóstico de esta entidad es habitualmente difícil lo que origina que a estos pacientes se les practiquen cirugías innecesarias, se les etiquete como enfermos psiquiátricos y el diagnóstico se realice varios años después del inicio de los síntomas. El tratamiento se dirige a mejorar los síntomas y a mantener su estado nutricional mediante medidas dietético-nutricionales, fármacos y actitudes endoscópico-quirúrgicas. La complejidad de estos enfermos aconseja su seguimiento multidisciplinar.Chronic intestinal pseudo-obstruction (CIPO is a syndrome characterized by the presence of recurrent episodes of clinical intestinal obstruction in the absence of obstructive lesions. Although this syndrome is rare, it causes a high morbidity. It is caused by a disturbance of the intestinal motility, that results in a failure of the progression of the intestinal content. Basically, the failure of the intestinal motility is a consequence of muscular disorder, neurological disorder or both

  17. Effect of moderator density distribution of annular flow on fuel assembly neutronic characteristics in boiling water reactor cores

    Energy Technology Data Exchange (ETDEWEB)

    Ama, Tsuyoshi; Hyoudou, Hideaki; Takeda, Toshikazu [Osaka Univ., Graduate School of Engineering, Suita, Osaka (Japan); Ikeda, Hideaki; Kosaka, Shinya [Tepco Systems Corp., In-core Fuel Management Department, Tokyo (Japan)

    2002-05-01

    The effect of the moderator density distribution of annular flow on the fuel assembly neutronic characteristics in a boiling water nuclear reactor was investigated using the SRAC95 code system. For the investigation, a model of annular flow for fuel assembly calculation was utilized. The results of the assembly calculation with the model (Method 1) and those of the fuel assembly calculation with the uniform void fraction distribution (Method 2) were compared. It was found that Method 2 underestimates the infinite multiplication factor in the fuel assembly including the gadolinia rod (type 1 assembly). This phenomenon is explained by the fact that the capture rate in the thermal energy region in gadolinia fuel is estimated to be smaller when the liquid film of annular flow at the fuel rod surface is considered. A burnup calculation was performed under the condition of a void fraction of 65% and a volumetric fraction of the liquid film in liquid phase of 1. It is found that Method 2 underestimates the infinite multiplication factor in comparison to Method 1 in the early stage of burnup, and that Method 2 becomes to overestimate the factor after a certain degree of burnup. This is because Method 2 overestimates the depletion rate of the gadolinia. (author)

  18. Collapsing criteria for vapor film around solid spheres as a fundamental stage leading to vapor explosion

    Energy Technology Data Exchange (ETDEWEB)

    Freud, Roy [Nuclear Research Center - Negev, Beer-Sheva (Israel)], E-mail: freud@bgu.ac.il; Harari, Ronen [Nuclear Research Center - Negev, Beer-Sheva (Israel); Sher, Eran [Pearlstone Center for Aeronautical Studies, Department of Mechanical Engineering, Ben-Gurion University, Beer-Sheva (Israel)

    2009-04-15

    Following a partial fuel-melting accident, a Fuel-Coolant Interaction (FCI) can result with the fragmentation of the melt into tiny droplets. A vapor film is then formed between the melt fragments and the coolant, while preventing a contact between them. Triggering, propagation and expansion typically follow the premixing stage. In the triggering stage, vapor film collapse around one or several of the fragments occurs. This collapse can be the result of fragments cooling, a sort of mechanical force, or by any other means. When the vapor film collapses and the coolant re-establishes contact with the dry surface of the hot melt, it may lead to a very rapid and rather violent boiling. In the propagation stage the shock wave front leads to stripping of the films surrounding adjacent droplets which enhance the fragmentation and the process escalates. During this process a large quantity of liquid vaporizes and its expansion can result in destructive mechanical damage to the surrounding structures. This multiphase thermal detonation in which high pressure shock wave is formed is regarded as 'vapor explosion'. The film boiling and its possible collapse is a fundamental stage leading to vapor explosion. If the interaction of the melt and the coolant does not result in a film boiling, no explosion occurs. Many studies have been devoted to determine the minimum temperature and heat flux that is required to maintain a film boiling. The present experimental study examines the minimum temperature that is required to maintain a film boiling around metal spheres immersed into a liquid (subcooled distilled water) reservoir. In order to simulate fuel fragments that are small in dimension and has mirror-like surface, small spheres coated with anti-oxidation layer were used. The heat flux from the spheres was calculated from the sphere's temperature profiles and the sphere's properties. The vapor film collapse was associated with a sharp rise of the heat flux

  19. Boiling water reactor radiation shielded Control Rod Drive Housing Supports

    Energy Technology Data Exchange (ETDEWEB)

    Baversten, B.; Linden, M.J. [ABB Combustion Engineering Nuclear Operations, Windsor, CT (United States)

    1995-03-01

    The Control Rod Drive (CRD) mechanisms are located in the area below the reactor vessel in a Boiling Water Reactor (BWR). Specifically, these CRDs are located between the bottom of the reactor vessel and above an interlocking structure of steel bars and rods, herein identified as CRD Housing Supports. The CRD Housing Supports are designed to limit the travel of a Control Rod and Control Rod Drive in the event that the CRD vessel attachement went to fail, allowing the CRD to be ejected from the vessel. By limiting the travel of the ejected CRD, the supports prevent a nuclear overpower excursion that could occur as a result of the ejected CRD. The Housing Support structure must be disassembled in order to remove CRDs for replacement or maintenance. The disassembly task can require a significant amount of outage time and personnel radiation exposure dependent on the number and location of the CRDs to be changed out. This paper presents a way to minimize personal radiation exposure through the re-design of the Housing Support structure. The following paragraphs also delineate a method of avoiding the awkward, manual, handling of the structure under the reactor vessel during a CRD change out.

  20. Model for boiling and dryout in particle beds. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Lipinski, R. J.

    1982-06-01

    Over the last ten years experiments and modeling of dryout in particle beds have produced over fifty papers. Considering only volume-heated beds, over 250 dryout measurements have been made, and are listed in this work. In addition, fifteen models to predict dryout have been produced and are discussed. A model is developed in this report for one-dimensional boiling and dryout in a porous medium. It is based on conservation laws for mass, momentum, and energy. The initial coupled differential equations are reduced to a single first-order differential equation with an algebraic equation for the upper boundary condition. The model includes the effects of both laminar and turbulent flow, two-phase friction, and capillary force. The boundary condition at the bed bottom includes the possibility of inflowing liquid and either an adiabatic or a bottom-cooled support structure. The top of the bed may be either channeled or subcooled. In the first case the channel length and the saturation at the base of the channels are predicted. In the latter case, a criterion for penetration of the subcooled zone by channels is obtained.

  1. TOBI: A nonlinear model for boiling water reactor stability analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wehle, F. (Siemens/KWU, Offenbach (West Germany)); Pruitt, D.W.

    1990-06-01

    The magnitude and the divergent nature of the oscillations during the LaSalle unit 2 nuclear power plant even on March 9, 1988, renewed concern about the state of knowledge on boiling water reactor (BWR) instabilities and was followed by many activities, e.g., the Idaho Stability Symposium. For appropriate representation of the physical processes, typical BWR time-domain stability calculations with, e.g., TRAC, RETRAN, or THERMIT require a large number of axial nodes and are very costly with regard to computer time. Linear models are inexpensive, but only valid as long as the parameters have no large deviation from the reference operating conditions. The objective of this work is the development of a physical model that is applicable for stability analysis in the nonlinear regime, but without the disadvantage of numerical problems and excessive computing times. The basic concept of the model TOBI is the integral study of the interaction between the time-dependent single- and two-phase regions. A series of calculations for purely thermal-hydraulic systems and BWRs has shown that TOBI is a convenient tool for stability analysis. Because of the simple but physically realistic modeling, it is very helpful in achieving an improved understanding of the mechanisms that affect BWR stability, and it is inexpensive, with regard to computer time, to perform extensive parameter sensitivity studies, even in the nonlinear regime.

  2. [Devitalization of salmonellal bacteria in boiled and smoked sausages].

    Science.gov (United States)

    Iordanov, I; Zakhariev, Ts; Dimitrov, Ia

    1980-01-01

    Laboratory and production experiments were carried for devitalizing bouillon cultures of 7 serological types of salmonella. The laboratory experiments (73) were made in water bath, the bouillon cultures being heated following the thermic curve for the production of boiled-fumigated sausages. The production experiments (11) were carried out on sausages having a diameter of: 30-40 mm, 50-60mm and 80-100 mm. The density of bacterial cells in the bouillon and in the meat mass was 2-42.10(6)/cm3. It was proved that in vitro the critical temperature for the devitalization of salmonellas was 62 degrees C (S. enteritidis, S. agona, S. typhimurium, S. oranienburg, S. choleraesnis, S. anatum, S. lexington). During the production experiments on the sausage 'in the Macedonian fashion', the 'Kamchia' sausage (ø50-60 mm) and the 'Roussé' sausage, the salmonellas tested (S. typhimurium, S. enteritidis, S. oranienburg, S. choleraesnis ans S. dublin) showed a critical devitalization temperature of 64 degrees C. It was proved that the devitalization of salmonellas depended on the critical temperature reached and was not influenced by the type of salmonella, the diameter and the structure of the sausages. For the isolation of salmonella bacteria from thermically treated meat products a preliminary enrichment in peptone water is necessary during 18-20 hours and a second sowing on hard and in liquid selective food media.

  3. Stability analysis on natural circulation boiling water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Metz, Peter

    1999-05-01

    The purpose of the study is a stability analysis of the simplified boiling water reactor concept. A fluid dynamics code, DYNOS, was developed and successfully validated against FRIGG and DESIRE data and a stability benchmark on the Ringhals 1 forced circulation BWR. Three simplified desings were considered in the analysis: The SWRIOOO by Siemens and the SBWR and ESBWR from the General Electric Co. For all three design operational characteristics, i.e. power versus flow rate maps, were calculated. The effects which different geometric and operational parameters, such as the riser height, inlet subcooling etc., have on the characteristics have been investigated. Dynamic simulations on the three simplified design revealed the geysering and the natural circulation oscillations modes only. They were, however, only encountered at pressure below 0.6 MPa. Stability maps for all tree simplified BWRs were calculated and plotted. The study concluded that a fast pressurisation of the reactor vessel is necessary to eliminate the possibility of geysering or natural circulation oscillations mode instability. (au) 26 tabs., 88 ills.

  4. Enzymatic maceration of bone: a gentler technique than boiling.

    Science.gov (United States)

    Uhre, Marie-Louise; Eriksen, Anne Marie; Simonsen, Kim Pilkjær; Rasmussen, Arne Redsted; Hjort, Benjamin Benn; Lynnerup, Niels

    2015-04-01

    This proof of concept study investigates the removal of soft tissue from human ribs with the use of two common methods: boiling with a laundry detergent and using enzymes. Six individuals were autopsied, and one rib from each individual was removed for testing. Each rib was cut into pieces and afterwards macerated by one of the two methods. DNA extraction was performed to see the effect of the macerations on DNA preservation. Furthermore, the bone pieces were examined in a stereomicroscope to assess for any bone damage. The results demonstrated that both methods removed all flesh/soft tissue from the bones. The DNA analysis showed that DNA was preserved on all the pieces of bones which were examined. Finally, the investigation suggests that enzyme maceration could be gentler on the bones, as the edges appeared less frayed. The enzyme maceration was also a quicker method; it took three hours compared with the traditional method which took about 24 hours. However, a more standardised study should be performed to confirm this. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  5. Hydrothermal synthesis of porous Co (OH) 2 nanoflake array film ...

    Indian Academy of Sciences (India)

    The pseudo-capacitive behaviour of the Co(OH)2 nanoflake array film is investigated by cyclic voltammograms (CV) and galvanostatic charge–discharge tests in 2MKOH. The -Co(OH)2 nanoflake array film exhibits high capacitances of 1017 F g-1 at 2Ag-1 and 890 F g-1 at 40Ag-1 as well as rather good cycling stability for ...

  6. Stress-induced phase transformation and pseudo-elastic/pseudo-plastic recovery in intermetallic Ni-Al nanowires.

    Science.gov (United States)

    Sutrakar, Vijay Kumar; Mahapatra, D Roy

    2009-07-22

    Extensive molecular dynamics (MD) simulations have been performed in a B2-NiAl nanowire using an embedded atom method (EAM) potential. We show a stress induced [Formula: see text]-centered-tetragonal (BCT) phase transformation and a novel temperature and cross-section dependent pseudo-elastic/pseudo-plastic recovery from such an unstable BCT phase with a recoverable strain of approximately 30% as compared to 5-8% in polycrystalline materials. Such a temperature and cross-section dependent pseudo-elastic/pseudo-plastic strain recovery can be useful in various interesting applications of shape memory and strain sensing in nanoscale devices. Effects of size, temperature, and strain rate on the structural and mechanical properties have also been analyzed in detail. For a given size of the nanowire the yield stress of both the B2 and the BCT phases is found to decrease with increasing temperature, whereas for a given temperature and strain rate the yield stress of both the B2 and the BCT phase is found to increase with increase in the cross-sectional dimensions of the nanowire. A constant elastic modulus of approximately 80 GPa of the B2 phase is observed in the temperature range of 200-500 K for nanowires of cross-sectional dimensions in the range of 17.22-28.712 A, whereas the elastic modulus of the BCT phase shows a decreasing trend with an increase in the temperature.

  7. Study of the internal heat transfer of the water flow in nucleate boiling; Estudio de la transferencia de calor del flujo interno de agua en ebullicion nucleada

    Energy Technology Data Exchange (ETDEWEB)

    Payan Rodriguez, Luis Alfredo

    2003-09-01

    In this paper the development of a research project oriented to the analysis of the heat transfer of the water flow in nucleate boiling is presented. Here a mathematical model is described to characterize the water flow in boiling condition in vertical tubes by means of which the temperature distributions in the tube wall and in the water flow are obtained, including the calculation of the pressure drop throughout the tube. In addition, a mechanistic model focused to the prediction of the critical heat flow in vertical tubes uniformly heated was modified to be applied in non-uniform heat flow conditions. The proposed mathematical models were used in a case study derived from a real problem in a thermoelectric power plant, where it was required to simulate the process of boiling in fireplace tubes of the steam generator to determine the causes of the faults that happened in a considerable number of tubes. With the obtained results it was possible to establish that the faults in the tubes of the analyzed steam generator were originated because the heat transfer rate in the fireplace reached critical values that caused the deviation of the nucleate boiling to film boiling, causing the diminution of the heat transfer coefficient with the consequent sudden increase in the tube wall temperature. [Spanish] En este trabajo se presenta el desarrollo de un proyecto de investigacion orientado al analisis de la transferencia de calor en flujo de agua en ebullicion nucleada. Aqui se describe un modelo matematico para caracterizar el flujo de agua en ebullicion en tubos verticales mediante el cual se obtienen las distribuciones de temperatura en la pared del tubo y en el flujo de agua, incluyendo el calculo de la caida de presion a lo largo del tubo. Ademas, un modelo mecanistico enfocado a la prediccion del flujo de calor critico en tubos verticales uniformemente calentados fue modificado para aplicarlo en condiciones de flujo de calor no uniforme. Los modelos matematicos

  8. Flow Boiling and Condensation Experiment (FBCE) for the International Space Station

    Science.gov (United States)

    Mudawar, Issam; Hasan, Mohammad M.; Kharangate, Chirag; O'Neill, Lucas; Konishi, Chris; Nahra, Henry; Hall, Nancy; Balasubramaniam, R.; Mackey, Jeffrey

    2015-01-01

    The proposed research aims to develop an integrated two-phase flow boiling/condensation facility for the International Space Station (ISS) to serve as primary platform for obtaining two-phase flow and heat transfer data in microgravity.

  9. Passive Capillary Pumped Cryocooling System for Zero-Boil-Off Cryogen Storage Tanks Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Significant cost and weight savings of a space mission can be achieved by improving the cryogenic storage technology. Added cryogen mass due to the cryogen boil-off,...

  10. Analytical solution of nucleate pool boiling heat transfer model based on macrolayer

    Science.gov (United States)

    Danish, Mohd; Al Mesfer, Mohammed K.

    2018-02-01

    In the present work, a transient heat conduction model has been developed for heat transfer through macrolayer in nucleate regime of pool boiling. The developed heat transfer model was solved analytically (Laplace Transform) using appropriate initial and boundary conditions. The influence of macrolayer thickness, wall superheat, and time on conduction heat flux has been predicted. The average conduction heat flux as a function of wall superheat and macrolayer thickness has also been predicted. The findings of the study have been compared with experimental results, and they are in reasonable agreement. For higher values of wall superheat, which correspond to nucleate pool boiling, predicted results agree with experimental data. Findings also substantiate the assertion that heat conduction across the macrolayer constitutes the major mode of heat transfer from the heated wall to the boiling liquid in the macrolayer regime of pool boiling.

  11. Boiling heat transfer on single phosphor bronze and copper mesh microstructures

    Directory of Open Access Journals (Sweden)

    Orman Łukasz J.

    2014-03-01

    Full Text Available The paper presents experimental results of boiling heat transfer of distilled water and ethyl alcohol on surfaces covered with single layers of wire mesh structures made of phosphor bronze and copper. For each material two kinds of structures have been considered (higher and lower in order to determine the impact of the height of the structure on boiling heat transfer. The wire diameter of the copper meshes was 0,25 mm and 0,32 mm, while of the bronze meshes: 0,20 mm and 0,25 mm. The structures had the same mesh aperture (distance between the wires – 0,50 mm for copper and 0,40 for bronze but different wire diameter and, consequently, different height of the layers. The tests have been performed under ambient pressure in the pool boiling mode. The obtained results indicate a visible impact of the layer height on the boiling heat transfer performance of the analysed microstructures.

  12. Analytical solution of nucleate pool boiling heat transfer model based on macrolayer

    Science.gov (United States)

    Danish, Mohd; Al Mesfer, Mohammed K.

    2017-08-01

    In the present work, a transient heat conduction model has been developed for heat transfer through macrolayer in nucleate regime of pool boiling. The developed heat transfer model was solved analytically (Laplace Transform) using appropriate initial and boundary conditions. The influence of macrolayer thickness, wall superheat, and time on conduction heat flux has been predicted. The average conduction heat flux as a function of wall superheat and macrolayer thickness has also been predicted. The findings of the study have been compared with experimental results, and they are in reasonable agreement. For higher values of wall superheat, which correspond to nucleate pool boiling, predicted results agree with experimental data. Findings also substantiate the assertion that heat conduction across the macrolayer constitutes the major mode of heat transfer from the heated wall to the boiling liquid in the macrolayer regime of pool boiling.

  13. Electrohydrodynamic (EHD) enhancement of boiling heat transfer of R113+WT4% ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Si Doek [Hyosung Corporation, Seoul (Korea, Republic of); Kwak, Ho Young [Chungang University, Seoul (Korea, Republic of)

    2006-05-15

    Nucleate boiling heat transfer for refrigerants, R113, and R113+wt14% ethanol mixture, an azeotropic mixture under electric field was investigated experimentally in a single-tube shell/tube heat exchanger. A special electrode configuration which provides a more uniform electric field that produces more higher voltage limit against the dielectric breakdown was used in this study. Experimental study has revealed that the electrical charge relaxation time is an important parameter for the boiling heat transfer enhancement under electric field. Up to 1210% enhancement of boiling heat transfer was obtained for R113+wt4% ethanol mixture which has the electrical charge relaxation time of 0.0053 sec whereas only 280% enhancement obtained for R113 which has relaxation time of 0.97 sec. With artificially machined boiling surface, more enhancement in the heat transfer coefficient in the azeotropic mixture was obtained.

  14. Pseudo sidescan images from backscatter amplitude data of the Hydrosweep multibean sonar system

    Digital Repository Service at National Institute of Oceanography (India)

    Kodagali, V.N.; Hagen, R.; Schenke, H.W.

    Using the rms (root mean square) backscatter amplitude values, a procedure was evolved to generate pseudo sidescan images. A comparison of the pseudo sidescan image with actual Hydrosweep sidescan image, from an area covering a pear shaped seamount...

  15. Regression analysis of restricted mean survival time based on pseudo-observations

    DEFF Research Database (Denmark)

    Andersen, Per Kragh; Hansen, Mette Gerster; Klein, John P.

    censoring; hazard function; health economics; regression model; survival analysis; mean survival time; restricted mean survival time; pseudo-observations......censoring; hazard function; health economics; regression model; survival analysis; mean survival time; restricted mean survival time; pseudo-observations...

  16. Regression Analysis of Restricted Mean Survival Time Based on Pseudo-Observations

    DEFF Research Database (Denmark)

    Andersen, Per Kragh; Hansen, Mette Gerster; Klein, John P.

    2004-01-01

    censoring; hazard function; health economics; mean survival time; pseudo-observations; regression model; restricted mean survival time; survival analysis......censoring; hazard function; health economics; mean survival time; pseudo-observations; regression model; restricted mean survival time; survival analysis...

  17. INEXTENSIBLE FLOWS OF CURVES IN THE EQUIFORM GEOMETRY OF THE PSEUDO-GALILEAN SPACE G13

    Directory of Open Access Journals (Sweden)

    HANDAN OZTEKIN

    2016-12-01

    Full Text Available In this paper, we study inextensible ows of curves in 3-dimensional pseudo- Galilean space. We give necessary and sucient conditions for inextensible ows of curves according to equiform geometry in pseudo-Galilean space.

  18. Generalised linear models for correlated pseudo-observations, with applications to multi-state models

    DEFF Research Database (Denmark)

    Andersen, Per Kragh; Klein, John P.; Rosthøj, Susanne

    2003-01-01

    Generalised estimating equation; Generalised linear model; Jackknife pseudo-value; Logistic regression; Markov Model; Multi-state model......Generalised estimating equation; Generalised linear model; Jackknife pseudo-value; Logistic regression; Markov Model; Multi-state model...

  19. Numerical simulation of pool boiling for steady state and transient heating

    Energy Technology Data Exchange (ETDEWEB)

    He, Ying; Shoji, Masahiro; Maruyama, Shigeo

    1999-07-01

    It's believed that the macrolayer plays an important role in nucleate and transition boiling heat transfer at high heat flux. Many experiments have been carried out to support the macrolayer evaporation model, however, little has been conducted in the numerical simulation of boiling heat transfer. In this study, based on the macrolayer evaporation model of Maruyama et al. (1992), a numerical simulation of pool boiling for steady state was carried out. The key points of the simulation are: (1) It is modeled that the macrolayer containing vapor stems occupies the region immediately next to the wall and that the vapor stems are formed on the active cavity sites. (2) Not only does the evaporation occur at the vapor bubble-macrolayer interface, but also at the liquid-vapor stem interface. (3) The macrolayers form periodically. No liquid is supplied to the macrolayers during the hovering period. While the vapor mass departs from the surface, the macrolayers replenish immediately despite the complicity of the transition period between the departures of two vapor masses. The major results are: (1) The boiling curves of water and FC-72 (C{sub 6}F{sub 14}) were reasonably predicted. (2) The temporal variations in surface temperature for different boiling regimes were obtained. Secondly, the simulation of transient pool boiling was conducted. It was realized with following assumptions: (1) The macrolayer evaporation model can be extended to the transient pool boiling. The macrolayer forms cyclically and its thickness is determined by the surface heat flux when the vapor mass takes off. (2) One-dimensional transient heat conduction within the heater coupled with the macrolayer model was considered. Being employed explicit FDM, the instantaneous surface temperature can be obtained. Therefore, the instantaneous heat flux can be calculated by applying the surface temperature into the macrolayer model. (3) In the transition-boiling regime, the initial thickness of macrolayer

  20. The impact of capillary structure properties on heat transfer from boiling in limited space

    OpenAIRE

    Баскова, Александра Александровна; Кравец, Владимир Юрьевич; Алексеик, Ольга Сергеевна; Лебедь, Наталия Леонидовна

    2015-01-01

    Modern cooling systems for radio and electronic equipment widely use heat pipes. The main element of heat pipes is capillary and porous structure (CPS), on which a heat transfer agent boils and condensates. Previous studies showed that intensity of heat transfer depends on geometric parameters of the CPS. Our research is devoted to analyzing experimental data on the intensity of heat transfer from boiling in limited space on the CPS with various fiber lengths. We have determined the impact of...

  1. Boiling of simulated tap water: effect on polar brominated disinfection byproducts, halogen speciation, and cytotoxicity.

    Science.gov (United States)

    Pan, Yang; Zhang, Xiangru; Wagner, Elizabeth D; Osiol, Jennifer; Plewa, Michael J

    2014-01-01

    Tap water typically contains numerous halogenated disinfection byproducts (DBPs) as a result of disinfection, especially of chlorination. Among halogenated DBPs, brominated ones are generally significantly more toxic than their chlorinated analogues. In this study, with the aid of ultra performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry by setting precursor ion scans of m/z 79/81, whole spectra of polar brominated DBPs in simulated tap water samples without and with boiling were revealed. Most polar brominated DBPs were thermally unstable and their levels were substantially reduced after boiling via decarboxylation or hydrolysis; the levels of a few aromatic brominated DBPs increased after boiling through decarboxylation of their precursors. A novel adsorption unit for volatile total organic halogen was designed, which enabled the evaluation of halogen speciation and mass balances in the simulated tap water samples during boiling. After boiling for 5 min, the overall level of brominated DBPs was reduced by 62.8%, of which 39.8% was volatilized and 23.0% was converted to bromide; the overall level of chlorinated DBPs was reduced by 61.1%, of which 44.4% was volatilized and 16.7% was converted to chloride; the overall level of halogenated DBPs was reduced by 62.3%. The simulated tap water sample without boiling was cytotoxic in a chronic (72 h) exposure to mammalian cells; this cytotoxicity was reduced by 76.9% after boiling for 5 min. The reduction in cytotoxicity corresponded with the reduction in overall halogenated DBPs. Thus, boiling of tap water can be regarded as a "detoxification" process and may reduce human exposure to halogenated DBPs through tap water ingestion.

  2. Starch characterization in seven raw, boiled and roasted chestnuts (Castanea sativa Mill.) cultivars from Portugal

    OpenAIRE

    Silva, A.P.; Oliveira, I. de; Silva, M. E.; Guedes, C. M.; Borges, O.; Magalhães, B.; Gonçalves, B.

    2015-01-01

    Changes occurring in seven chestnut (Castanea sativa sp.) cultivars, caused by boiling and roasting, on starch content, cell and starch granules dimension were evaluated, and morphological changes were characterized by scanning electron microscopy. Three clear patterns of variation were detected after processing, namely: i) decrease of starch content with processing; ii) starch increase with the applied treatments; iii) increase of starch with boiling and decrease with roasting. Starch granul...

  3. Heat Transfer of Single and Binary Systems inPool Boiling

    OpenAIRE

    Abbas J. Sultan; Balasim A. Abid

    2010-01-01

    The present research focuses on the study of the effect of mass transfer resistance on the rate of heat transfer in pool boiling. The nucleate pool boiling heat transfer coefficients for binary mixtures (ethanol-n-butanol, acetone-n-butanol, acetone-ethanol, hexane-benzene, hexane-heptane, and methanol-water) were measured at different concentrations of the more volatile components. The systems chosen covered a wide range of mixture behaviors.The experimental set up for the present investigat...

  4. Heat transfer at boiling of refrigerants in channels with twisted tape insert

    Science.gov (United States)

    Shishkin, A. V.; Tarasevich, S. E.; Yakovlev, A. B.

    2017-10-01

    The paper presents the review results of heat transfer at boiling in channels with twisted tape inserts. Various methods and approaches to the research of heat transfer processes at boiling of refrigerants in channels with twisted tape inserts were identified, a significant difference of the influencing factors on the heat transfer depending on the range of regime parameters under study was noted and also the necessity for research in this field was shown.

  5. A novel pseudo-complementary PNA G-C base pair

    DEFF Research Database (Denmark)

    Olsen, Anne G.; Dahl, Otto; Petersen, Asger Bjørn

    2011-01-01

    Pseudo-complementary oligonucleotide analogues and mimics provide novel opportunities for targeting duplex structures in RNA and DNA. Previously, a pseudo-complementary A-T base pair has been introduced. Towards sequence unrestricted targeting, a pseudo-complementary G-C base pair consisting...... of the unnatural nucleobases n6-methoxy-2,6-diaminopurine (previously described in a DNA context) and N4-benzoylcytosine is now presented for design of pseudo-complementary PNA oligomers (pcPNAs)....

  6. Laboratory study of non-aqueous phase liquid and water co-boiling during thermal treatment.

    Science.gov (United States)

    Zhao, C; Mumford, K G; Kueper, B H

    2014-08-01

    In situ thermal treatment technologies, such as electrical resistance heating and thermal conductive heating, use subsurface temperature measurements in addition to the analysis of soil and groundwater samples to monitor remediation performance. One potential indication of non-aqueous phase liquid (NAPL) removal is an increase in temperature following observations of a co-boiling plateau, during which subsurface temperatures remain constant as NAPL and water co-boil. However, observed co-boiling temperatures can be affected by the composition of the NAPL and the proximity of the NAPL to the temperature measurement location. Results of laboratory heating experiments using single-component and multi-component NAPLs showed that local-scale temperature measurements can be mistakenly interpreted as an indication of the end of NAPL-water co-boiling, and that significant NAPL saturations (1% to 9%) remain despite observed increases in temperature. Furthermore, co-boiling of multi-component NAPL results in gradually increasing temperature, rather than a co-boiling plateau. Measurements of gas production can serve as a complementary metric for assessing NAPL removal by providing a larger-scale measurement integrated over multiple smaller-scale NAPL locations. Measurements of the composition of the NAPL condensate can provide ISTT operators with information regarding the progress of NAPL removal for multi-component sources. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Identification of quantitative trait loci associated with boiled seed hardness in soybean

    Science.gov (United States)

    Hirata, Kaori; Masuda, Ryoichi; Tsubokura, Yasutaka; Yasui, Takeshi; Yamada, Tetsuya; Takahashi, Koji; Nagaya, Taiko; Sayama, Takashi; Ishimoto, Masao; Hajika, Makita

    2014-01-01

    Boiled seed hardness is an important factor in the processing of soybean food products such as nimame and natto. Little information is available on the genetic basis for boiled seed hardness, despite the wide variation in this trait. DNA markers linked to the gene controlling this trait should be useful in soybean breeding programs because of the difficulty of its evaluation. In this report, quantitative trait locus (QTL) analysis was performed to reveal the genetic factors associated with boiled seed hardness using a recombinant inbred line population developed from a cross between two Japanese cultivars, ‘Natto-shoryu’ and ‘Hyoukei-kuro 3’, which differ largely in boiled seed hardness, which in ‘Natto-shoryu’ is about twice that of ‘Hyoukei-kuro 3’. Two significantly stable QTLs, qHbs3-1 and qHbs6-1, were identified on chromosomes 3 and 6, for which the ‘Hyoukei-kuro 3’ alleles contribute to decrease boiled seed hardness for both QTLs. qHbs3-1 also showed significant effects in progeny of a residual heterozygous line and in a different segregating population. Given its substantial effect on boiled seed hardness, SSR markers closely linked to qHbs3-1, such as BARCSOYSSR_03_0165 and BARCSOYSSR_03_0185, could be useful for marker-assisted selection in soybean breeding. PMID:25914591

  8. Sensory quality and appropriateness of raw and boiled Jerusalem artichoke tubers (Helianthus tuberosus L.).

    Science.gov (United States)

    Bach, Vibe; Kidmose, Ulla; Thybo, Anette K; Edelenbos, Merete

    2013-03-30

    The aim of the present study was to investigate the sensory attributes, dry matter and sugar content of five varieties of Jerusalem artichoke tubers and their relation to the appropriateness of the tubers for raw and boiled preparation. Sensory evaluation of raw and boiled Jerusalem artichoke tubers was performed by a trained sensory panel and a semi-trained consumer panel of 49 participants, who also evaluated the appropriateness of the tubers for raw and boiled preparation. The appropriateness of raw Jerusalem artichoke tubers was related to Jerusalem artichoke flavour, green nut flavour, sweetness and colour intensity, whereas the appropriateness of boiled tubers was related to celeriac aroma, sweet aroma, sweetness and colour intensity. In both preparations the variety Dwarf stood out from the others by being the least appropriate tuber. A few sensory attributes can be used as predictors of the appropriateness of Jerusalem artichoke tubers for raw and boiled consumption. Knowledge on the quality of raw and boiled Jerusalem artichoke tubers can be used to inform consumers on the right choice of raw material and thereby increase the consumption of the vegetable. © 2012 Society of Chemical Industry.

  9. Stagewise pseudo-value regression for time-varying effects on the cumulative incidence

    DEFF Research Database (Denmark)

    Zöller, Daniela; Schmidtmann, Irene; Weinmann, Arndt

    2016-01-01

    using a pseudo-value approach. For a grid of time points, the possibly unobserved binary event status is replaced by a jackknife pseudo-value based on the Aalen-Johansen method. We combine a stagewise regression technique with the pseudo-value approach to provide variable selection while allowing...

  10. Biharmonic Submanifolds with Parallel Mean Curvature Vector in Pseudo-Euclidean Spaces

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Yu, E-mail: yufudufe@gmail.com [Dongbei University of Finance and Economics, School of Mathematics and Quantitative Economics (China)

    2013-12-15

    In this paper, we investigate biharmonic submanifolds in pseudo-Euclidean spaces with arbitrary index and dimension. We give a complete classification of biharmonic spacelike submanifolds with parallel mean curvature vector in pseudo-Euclidean spaces. We also determine all biharmonic Lorentzian surfaces with parallel mean curvature vector field in pseudo-Euclidean spaces.

  11. Passive gamma analysis of the boiling-water-reactor assemblies

    Science.gov (United States)

    Vo, D.; Favalli, A.; Grogan, B.; Jansson, P.; Liljenfeldt, H.; Mozin, V.; Schwalbach, P.; Sjöland, A.; Tobin, S.; Trellue, H.; Vaccaro, S.

    2016-09-01

    This research focused on the analysis of a set of stationary passive gamma measurements taken on the spent nuclear fuel assemblies from a boiling water reactor (BWR) using pulse height analysis data acquisition. The measurements were performed on 25 different BWR assemblies in 2014 at Sweden's Central Interim Storage Facility for Spent Nuclear Fuel (Clab). This study was performed as part of the Next Generation of Safeguards Initiative-Spent Fuel project to research the application of nondestructive assay (NDA) to spent fuel assemblies. The NGSI-SF team is working to achieve the following technical goals more easily and efficiently than in the past using nondestructive assay (NDA) measurements of spent fuel assemblies: (1) verify the initial enrichment, burnup, and cooling time of facility declaration; (2) detect the diversion or replacement of pins, (3) estimate the plutonium mass, (4) estimate the decay heat, and (5) determine the reactivity of spent fuel assemblies. The final objective of this project is to quantify the capability of several integrated NDA instruments to meet the aforementioned goals using the combined signatures of neutrons, gamma rays, and heat. This report presents a selection of the measured data and summarizes an analysis of the results. Specifically, trends in the count rates measured for spectral lines from the following isotopes were analyzed as a function of the declared burnup and cooling time: 137Cs, 154Eu, 134Cs, and to a lesser extent, 106Ru and 144Ce. From these measured count rates, predictive algorithms were developed to enable the estimation of the burnup and cooling time. Furthermore, these algorithms were benchmarked on a set of assemblies not included in the standard assemblies set used by this research team.

  12. Experiences with austenitic steels in boiling water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Wachter, O. [Preussische Elektrizitaets-AG (Preussenelektra), Hannover (Germany); Bruemmer, G. [Hamburgische Electricitaets-Werke AG., Hamburg (Germany)

    1997-05-01

    Stabilized austenitic steels are susceptible to intergranular stress corrosion cracking (IGSCC) under boiling water reactor (BWR) conditions. This important finding for the German nuclear power station industry arises from the detection of cracks during the last 3 years in reactor hot water pipes made from titanium-stabilized steel AISI 321 in six BWRs and in reactor core components made from the niobium-stabilized steel AISI 347 in one BWR. All the observed cracks had a common feature: they had their origin in the chromium carbide precipitates at the grain boundaries and in the associated chromium-depleted region near the grain boundary. These microstructural features in the heat-affected zones of the hot water pipe weldments were caused by the heat input during deposition of the root bead. The TiC partially dissolved in the region near the fusion line and the released carbon reacted to form chromium-rich M{sub 23}C{sub 6}. Regarding the cracks found in the core shroud and the core grid plates, it was shown that a sensitizing heat treatment of rings taken from the same heat of steel could give rise to a microstructure susceptible to IGSCC in the region of a weldment. High carbon contents coupled with low stabilization ratios led to sensitization. Residual stresses developed during welding provided the significant contributions to the tensile stress necessary for IGSCC. With regard to the service medium, the influence of the electrochemical corrosion potential (ECP) was recognized as a dominant factor, together with the conductivity. The corrosion potential was mainly determined by the radiolytic formation of H{sub 2}O{sub 2}; with increasing distance from the core, the H{sub 2}O{sub 2} content decreased owing to catalytic decomposition. For the pipes the problem of IGSCC could be resolved by the use of optimized steel (lower carbon content with maximum allowable stabilization ratio).

  13. Cryogenic disturbance and its impact on soils of frost boil ecosystems of Taz peninsula, West Siberia

    Science.gov (United States)

    Myshonkov, Alexander; Matyshak, George; Petrzhik, Natalia

    2017-04-01

    For the last years there is an active development of permafrost zone, which is about 60% of the territory of Russia. More than 15% of this area belong to different types of tundra. Frost boil ecosystems, the formation of which is associated with the cryogenesis and cryogenic disturbance processes are one of the most specific tundra landscape. Such landscape forms of tundra ecosystems cover the area over 68000 sq. km - 20% of total Russian tundra area. Cryogenic processes leading to the formation of patterned ground (such as frost boils, non-sorted circles, ice-wedge polygons) are important mechanisms, which control the landscape distribution of soil and phytomass carbon in continuous permafrost terrain. Frost boil ecosystem's properties have been poorly studied. So, the aim of this work is to explore the functioning parameters and properties of frost boil soils. The object - frost boil ecosystems, - is located in the southern tundra of Taz peninsula, about 150 km north from Novy Urengoy (57°28 '50,6″ N, 76°42 '32,6″ E). Frost boils are small (0,5-2 m diameter and 5-15 cm height), barren, non-sorted circles separated by completely vegetated (moss-lichens and shrubs) troughs - interboils. Our monitoring section (100 sq. m.) was set on a typical frost-boil landscape. Within this area we obtained moisture content and temperature of upper layer (0-10 cm), active layer depth, CO2 flux. This analyzed site includes more than 40 frost boils. Measurements were made both on boil and interboil patches in 10-20 replicates. Samples were taken both from frost boils and interboils upper layers as well as from horizons two soil pit profiles. Different soil parameters were obtained by laboratory analysis: pH (1: 2,5), BR, SIR (Anderson, 1978), TC, DOC (Kalbitz, 2003). It is estimated that total area with frost boils is approx. twice larger than troughs area with vegetation cover within the monitoring site. The soil properties of frost boil and interboil are significantly

  14. Quasi-one dimensional in-plane conductivity in filamentary films of PEDOT:PSS

    NARCIS (Netherlands)

    Ruit, K. van de; Cohen, R.I.; Bollen, D.; Mol, T. van; Yerushalmi-Rozen, R.; Janssen, R.A.J.; Kemerink, M.

    2013-01-01

    The mechanism and magnitude of the in-plane conductivity of poly(3,4-ethy-lenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin films is determined using temperature dependent conductivity measurements for various PEDOT:PSS weight ratios with and without a high boiling solvent (HBS). Without

  15. Pseudo-nitzschia pungens (Bacillariophyceae): A cosmopolitan species?

    DEFF Research Database (Denmark)

    Casteleyn, G; Chepurnov, VA; Leliaert, F

    2007-01-01

    Abstract Genetic, reproductive and morphological variation were studied in 193 global strains of the marine diatom species Pseudo-nitzschia pungens (Grunow ex Cleve) Hasle to assess potential intraspecific variation and biogeographic distribution patterns. Genetic differentiation between allo- an...... Zealand) and the NE Pacific (Washington State). Clade I thus appears to be globally distributed in temperate coastal areas and provides the first strong evidence to date for the global distribution of a biologically, genetically and morphologically defined diatom species.......Abstract Genetic, reproductive and morphological variation were studied in 193 global strains of the marine diatom species Pseudo-nitzschia pungens (Grunow ex Cleve) Hasle to assess potential intraspecific variation and biogeographic distribution patterns. Genetic differentiation between allo...

  16. Chaos-based Pseudo-random Number Generation

    KAUST Repository

    Barakat, Mohamed L.

    2014-04-10

    Various methods and systems related to chaos-based pseudo-random number generation are presented. In one example, among others, a system includes a pseudo-random number generator (PRNG) to generate a series of digital outputs and a nonlinear post processing circuit to perform an exclusive OR (XOR) operation on a first portion of a current digital output of the PRNG and a permutated version of a corresponding first portion of a previous post processed output to generate a corresponding first portion of a current post processed output. In another example, a method includes receiving at least a first portion of a current output from a PRNG and performing an XOR operation on the first portion of the current PRNG output with a permutated version of a corresponding first portion of a previous post processed output to generate a corresponding first portion of a current post processed output.

  17. International conference Fourier Analysis and Pseudo-Differential Operators

    CERN Document Server

    Turunen, Ville; Fourier Analysis : Pseudo-differential Operators, Time-Frequency Analysis and Partial Differential Equations

    2014-01-01

    This book is devoted to the broad field of Fourier analysis and its applications to several areas of mathematics, including problems in the theory of pseudo-differential operators, partial differential equations, and time-frequency analysis. This collection of 20 refereed articles is based on selected talks given at the international conference “Fourier Analysis and Pseudo-Differential Operators,” June 25–30, 2012, at Aalto University, Finland, and presents the latest advances in the field. The conference was a satellite meeting of the 6th European Congress of Mathematics, which took place in Krakow in July 2012; it was also the 6th meeting in the series “Fourier Analysis and Partial Differential Equations.”

  18. Superconducting states in pseudo-Landau-levels of strained graphene.

    Science.gov (United States)

    Uchoa, Bruno; Barlas, Yafis

    2013-07-26

    We describe the formation of superconducting states in graphene in the presence of pseudo-Landau-levels induced by strain, when time reversal symmetry is preserved. We show that superconductivity in strained graphene is quantum critical when the pseudo-Landau-levels are completely filled, whereas at partial fillings superconductivity survives at weak coupling. In the weak coupling limit, the critical temperature scales linearly with the coupling strength and shows a sequence of quantum critical points as a function of the filling factor that can be accessed experimentally. We argue that superconductivity can be induced by electron-phonon coupling and that the transition temperature can be controlled with the amount of strain and with the filling fraction of the Landau levels.

  19. Pseudo natural colour aerial imagery for urban and suburban mapping

    DEFF Research Database (Denmark)

    Knudsen, Thomas

    2005-01-01

    Due to their near-infrared data channel, digital airborne four-channel imagers provide a potentially good discrimination between vegetation and human-made materials, which is very useful in automated mapping. Due to their red, green and blue data channels, they also provide natural colour images......, which are very useful in traditional (manual) mapping. In this paper, an algorithm is described which provides an approximation to the spectral capabilities of the four-channel imagers by using a colour-infrared aerial photo as input. The algorithm is tailored to urban/suburban surroundings, where...... the quality of the generated (pseudo) natural colour images are fully acceptable for manual mapping. This brings the combined availability of near-infrared and (pseudo) natural colours within reach for mapping projects based on traditional photogrammetry, which is valuable since traditional analytical cameras...

  20. Using of "pseudo-second-order model" in adsorption.

    Science.gov (United States)

    Ho, Yuh-Shan

    2014-01-01

    A research paper's contribution exists not only in its originality and creativity but also in its continuity and development for research that follows. However, the author easily ignores it. Citation error and quotation error occurred very frequently in a scientific paper. Numerous researchers use secondary references without knowing the original idea from authors. Sulaymon et al. (Environ Sci Pollut Res 20:3011-3023, 2013) and Spiridon et al. (Environ Sci Pollut Res 20:6367-6381, 2013) presented wrong pseudo-second-order models in Environmental Science and Pollution Research, vol. 20. This comment pointed the errors of the kinetic models and offered information for citing original idea of pseudo-second-order kinetic expression. In order to stop the proliferation of the mistake, it is suggested to cite the original paper for the kinetic model which provided greater accuracy and more details about the kinetic expression.

  1. Chronic intestinal pseudo-obstruction in a dog: case report

    Directory of Open Access Journals (Sweden)

    A.L. Bicalho

    2011-12-01

    Full Text Available Intestinal pseudo-obstruction is a rare disorder that affects gastrointestinal propulsion. It may be secondary to several pathological conditions or it may develop without a known cause. A 1.2 year-old intact Pug bitch had a history of vomiting and constipation, which were followed by diarrhea and distended abdomen. Hypomotility and dilation of the small intestine, which was filled with gas, were observed during laparotomy. Histologically, full thickness biopsy specimens demonstrated a severe loss and degeneration of leiomyocytes in the inner and outer muscular layers of the intestinal wall, whereas there was a marked hypertrophy and hyperplasia of smooth muscle cells in the lamina propria, and extremely thickened muscularis mucosae arranged in bundles oriented in different directions with marked hypertrophy and hyperplasia of leiomyocytes. Distribution of leiomyocytes was further characterized by immunohistochemistry. These findings support the diagnosis of intestinal pseudo-obstruction in a Pug, associated with degeneration and loss of leiomyocytes in the muscular layer.

  2. Nearly pseudo-Kähler manifolds and related special holonomies

    CERN Document Server

    Schäfer, Lars

    2017-01-01

    Developing and providing an overview of recent results on nearly Kähler geometry on pseudo-Riemannian manifolds, this monograph emphasizes the differences with the classical Riemannian geometry setting. The focal objects of the text are related to special holonomy and Killing spinors and have applications in high energy physics, such as supergravity and string theory. Before starting into the field, a self-contained introduction to the subject is given, aimed at students with a solid background in differential geometry. The book will therefore be accessible to masters and Ph.D. students who are beginning work on nearly Kähler geometry in pseudo-Riemannian signature, and also to non-experts interested in gaining an overview of the subject.  Moreover, a number of results and techniques are provided which will be helpful for differential geometers as well as for high energy physicists interested in the mathematical background of the geometric objects they need.

  3. Chronic primary intestinal pseudo-obstruction from visceral myopathy.

    Science.gov (United States)

    Muñoz-Yagüe, M T; Marín, J C; Colina, F; Ibarrola, C; López-Alonso, G; Martín, M A; Solís-Herruzo, J A

    2006-04-01

    Chronic intestinal pseudo-obstruction is an uncommon syndrome characterized by relapsing episodes suggesting intestinal obstruction during which no mechanical causes are identified to account for symptoms. Etiologic factors may be manifold. Among them a number of neurologic conditions, gastrointestinal smooth muscle myopathies, endocrino-metabolic and autoimmune diseases, and the use of selected drugs stand out. We report a case of chronic intestinal pseudo-obstruction originating in a sporadic, primary intestinal myopathy that corresponds to no type thus far described. A histological study of the intestinal wall showed disrupted muscle bundles and the presence of interstitial edema. Myocytes had severe degenerative changes, and no alterations were seen in submucosal and myenteric plexus neurons. The activity of enzyme complexes in the mitochondrial respiratory chain, and of thymidine phosphorylase was normal. No mitochondrial DNA changes were seen.

  4. A mathematical model for a pseudo-plastic welding joint

    OpenAIRE

    Iosifescu, Oana; Juntharee, Pongpol; Licht, Christian; Michaille, Gérard

    2009-01-01

    An elementary situation in welding involves the perfect assembly of two adherents and a strong adhesive occupying a thin layer. The bulk energy density of the hyperelastic adherents grows superlinearly while that of the pseudo-plastic adhesive grows linearly with a stiffness of the order of the inverse of its thickness epsilon. We propose a simplified but accurate model by studying the asymptotic behavior, when epsilon goes to zero, through variational convergence methods: at the limit, the i...

  5. La tuberculose abdominale pseudo-tumorale | El Barni | Pan African ...

    African Journals Online (AJOL)

    Même en l'absence d'antécédents de tuberculose pulmonaire, le diagnostic tuberculose abdominale pseudo-tumorale doit être évoqué surtout dans un pays d'endémie comme le notre et le recours à une laparotomie est justifié chaque fois que persiste un doute diagnostique ou en cas de complication. Pan African Medical ...

  6. Les pseudo nodules thyroidiens | Chahed | Journal Tunisien d'ORL ...

    African Journals Online (AJOL)

    L'examen cytologique fait par une personne entraînée peut être contributif au diagnostic différentiel. Cependant, le diagnostic se fait souvent après cervicotomie exploratrice. Mots clés : pseudo- nodule, thyroïde, kyste hydatique, schwannome, adénome parathyroïdien, kyste du tractus thyréoglosse, chondrosarcome ...

  7. mRNA-Producing Pseudo-nucleus System.

    Science.gov (United States)

    Shin, Seung Won; Park, Kyung Soo; Shin, Woo Jung; Um, Soong Ho

    2015-11-04

    A pseudo-eukaryotic nucleus (PEN) system consisting of a gene-containing DNA hydrogel encapsulated in a liposome is fabricated. Owing to the structural characteristics of gene-containing DNA hydrogel, mRNA transcription efficiency is promoted 2.57-fold. Through the use of PEN as a platform for mRNA delivery to the cytosol, prolonged protein translation is achieved. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Regression analysis of censored data using pseudo-observations

    DEFF Research Database (Denmark)

    Overgaard, Morten; Andersen, Per K.; Parner, Erik T.

    2015-01-01

    We present updated versions of the stpsurv, stpci, and stpmean commands, which were introduced in Parner and Andersen (2010, Stata Journal 10: 408–422), along with a new command, stplost. The commands generate pseudo-observations of the survival function, the cumulative incidence function under...... commands feature new options, an increase in computational speed, and the ability to handle survival data with delayed entry....

  9. Core curriculum case illustration: blunt traumatic thoracic aortic pseudo aneurysm.

    Science.gov (United States)

    Ramzan, Muhammad Mubashir; Fadl, Shaimaa Abdelhassib; Robinson, Jeffrey D

    2017-06-19

    Core Curriculum Illustration: [blunt thoracic aortic pseudo aneurysm]. This is the [40th] installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at: http://www.aseronline.org/curriculum/toc.html.

  10. La forme pseudo tumorale de la tuberculose primitive du nasopharynx

    African Journals Online (AJOL)

    La tuberculose primitive du nasopharynx est rare, nous présentons deux observations révélées par un aspect pseudo tumoral et à travers lesquelles nous soulevons le problème de diagnostic différentiel avec les lésions malignes du nasopharynx. La première observation concerne un jeune patient de 22 ans hospitalisé ...

  11. Top-Mode pseudo-Nambu-Goldstone Boson Higgs model

    Science.gov (United States)

    Fukano, Hidenori S.

    2017-12-01

    We discuss the Top-Mode pseudo-Nambu-Goldstone Boson Higgs (TMpNGBH) model which has recently been proposed as a variant of the top quark condensate model in light of the 125 GeV Higgs boson discovered at the LHC. In this talk, we focus on the vacuum alignment and the phenomenologies of characteristic particles of the TMpNGBH model.

  12. Pseudo Knowledge Sharing: The Influence of Trust and Guanxi Orientation

    OpenAIRE

    See-Kwong Goh; Poh-Yee Nee

    2015-01-01

    Despite the fact that knowledge sharing has been deemed as a competitive advantage and business sustainability tools for organizations, however many researcher has underpinned the deleterious impact knowledge sharing can bring forth to an organization performance. To date, it is found that minimal empirical research has been devoted to the dark side of knowledge sharing activities. Thus, this present study aims to extend this aspect specifically on pseudo knowledge sharing (PKS). The present ...

  13. Discrete Pseudo-SINR-Balancing Nonlinear Recurrent System

    Directory of Open Access Journals (Sweden)

    Zekeriya Uykan

    2013-01-01

    system and extend the results in Uykan (2009, which are for autonomous linear systems, to nonlinear case. The proposed system can be viewed as a discrete-time realization of a recently proposed continuous-time network in Uykan (2013. In this paper, we focus on discrete-time analysis and provide various novel key results concerning the discrete-time dynamics of the proposed system, some of which are as follows: (i the proposed system is shown to be stable in synchronous and asynchronous work mode in discrete time; (ii a novel concept called Pseudo-SINR (pseudo-signal-to-interference-noise ratio is introduced for discrete-time nonlinear systems; (iii it is shown that when the system states approach an equilibrium point, the instantaneous Pseudo-SINRs are balanced; that is, they are equal to a target value. The simulation results confirm the novel results presented and show the effectiveness of the proposed discrete-time network as applied to various associative memory systems and clustering problems.

  14. Pseudo-Reference-Based Assembly of Vertebrate Transcriptomes

    Directory of Open Access Journals (Sweden)

    Kyoungwoo Nam

    2016-02-01

    Full Text Available High-throughput RNA sequencing (RNA-seq provides a comprehensive picture of the transcriptome, including the identity, structure, quantity, and variability of expressed transcripts in cells, through the assembly of sequenced short RNA-seq reads. Although the reference-based approach guarantees the high quality of the resulting transcriptome, this approach is only applicable when the relevant reference genome is present. Here, we developed a pseudo-reference-based assembly (PRA that reconstructs a transcriptome based on a linear regression function of the optimized mapping parameters and genetic distances of the closest species. Using the linear model, we reconstructed transcriptomes of four different aves, the white leg horn, turkey, duck, and zebra finch, with the Gallus gallus genome as a pseudo-reference, and of three primates, the chimpanzee, gorilla, and macaque, with the human genome as a pseudo-reference. The resulting transcriptomes show that the PRAs outperformed the de novo approach for species with within about 10% mutation rate among orthologous transcriptomes, enough to cover distantly related species as far as chicken and duck. Taken together, we suggest that the PRA method can be used as a tool for reconstructing transcriptome maps of vertebrates whose genomes have not yet been sequenced.

  15. Evolution equations in generalized Stepanov-like pseudo almost automorphic spaces

    Directory of Open Access Journals (Sweden)

    Toka Diagana

    2012-03-01

    Full Text Available In this article, first we introduce and study the concept of $mathbb{S}_{gamma}^p$-pseudo almost automorphy (or generalized Stepanov-like pseudo almost automorphy, which is more general than the notion of Stepanov-like pseudo almost automorphy due to Diagana. We next study the existence of solutions to some classes of nonautonomous differential equations of Sobolev type in $mathbb{S}_{gamma}^p$-pseudo almost automorphic spaces. To illustrate our abstract result, we will study the existence and uniqueness of a pseudo almost automorphic solution to the heat equation with a negative time-dependent diffusion coefficient.

  16. Research on pseudo-color image generation technology of the distribution of gaseous pollutants

    Science.gov (United States)

    Yang, Jiao; Sheng, HuaiJie; Shao, Li; Cheng, YuBao

    2016-11-01

    In order to improve the visualization of the output data of gaseous pollutants monitoring system and study pseudo-color image generation technology, this research combines the column concentration data of polluted gas with spatial position parameter to design a grey-color conversion method based on visual pseudo-color coding, generates the pseudo-color images of column concentration of the distribution of polluted gas and evaluates the pseudo-color coding scheme designed in HSI color space. The evaluation results show that the designed coding scheme can effectively conduct pseudo-color display for the concentration section of polluted gas.

  17. Sorption and agglutination phenomenon of nanofluids on a plain heating surface during pool boiling

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhen-hua; Liao, Liang [School of Mechanical and Power Engineering, Shanghai Jiaotong University, 200030 Shanghai (China)

    2008-05-15

    The pool nucleate boiling heat transfer experiments of water (H{sub 2}O) based and alcohol (C{sub 2}H{sub 5}OH) based nanofluids and nanoparticles-suspensions on the plain heated copper surface were carried out. The study was focused on the sorption and agglutination phenomenon of nanofluids on a heated surface. The nanofluids consisted of the base liquid, the nanoparticles and the surfactant. The nanoparticles-suspensions consisted of the base liquid and nanoparticles. The both liquids of water and alcohol and both nanoparticles of CuO and SiO{sub 2} were used. The surfactant was sodium dodecyl benzene sulphate (SDBS). The experimental results show that for nanofluids, the agglutination phenomenon occurred on the heated surface when the wall temperature was over 112{sup o}C and steady nucleated boiling experiment could not be carried out. The reason was that an unsteady porous agglutination layer was formed on the heated surface. However, for nanoparticles-suspensions, no agglutination phenomenon occurred on the heating surface and the steady boiling could be carried out in the whole nucleate boiling region. For the both of alcohol based nanofluids and nano-suspensions, no agglutination phenomenon occurred on the heating surface and steady nucleate boiling experiment could be carried out in the whole nucleate boiling region whose wall temperature did not exceed 112{sup o}C. The boiling heat transfer characteristics of the nanofluids and nanoparticles-suspensions are somewhat poor compared with that of the base fluids, since the decrease of the active nucleate cavities on the heating surface with a very thin nanoparticles sorption layer. The very thin nanoparticles sorption layer also caused a decrease in the solid-liquid contact angle on the heating surface which leaded to an increase of the critical heat flux (CHF). (author)

  18. Assessing the microbiological performance and potential cost of boiling drinking water in urban Zambia.

    Science.gov (United States)

    Psutka, Rebecca; Peletz, Rachel; Michelo, Sandford; Kelly, Paul; Clasen, Thomas

    2011-07-15

    Boiling is the most common method of disinfecting water in the home and the benchmark against which other point-of-use water treatment is measured. In a six-week study in peri-urban Zambia, we assessed the microbiological effectiveness and potential cost of boiling among 49 households without a water connection who reported "always" or "almost always" boiling their water before drinking it. Source and household drinking water samples were compared weekly for thermotolerant coliforms (TTC), an indicator of fecal contamination. Demographics, costs, and other information were collected through surveys and structured observations. Drinking water samples taken at the household (geometric mean 7.2 TTC/100 mL, 95% CI, 5.4-9.7) were actually worse in microbiological quality than source water (geometric mean 4.0 TTC/100 mL, 95% CI, 3.1-5.1) (p water samples were reported to have actually been boiled at the time of collection from the home, suggesting over-reporting and inconsistent compliance. However, these samples were of no higher microbiological quality. Evidence suggests that water quality deteriorated after boiling due to lack of residual protection and unsafe storage and handling. The potential cost of fuel or electricity for boiling was estimated at 5% and 7% of income, respectively. In this setting where microbiological water quality was relatively good at the source, safe-storage practices that minimize recontamination may be more effective in managing the risk of disease from drinking water at a fraction of the cost of boiling.

  19. Experimental investigation of pool boiling of water-based AL2O3 nanofluid on a copper cylinder

    Directory of Open Access Journals (Sweden)

    Pryazhnikov Maxim

    2017-01-01

    Full Text Available Saturated boiling of nanofluid on a copper cylinder is experimentally studied. The studied nanofluid were prepared using distilled water and Al2O3 nanoparticles. The volume concentration of the nanoparticles was equal 3 %. Cylinder diameter was equal 25 mm. The time dependence on the excess temperature at different boiling regimes were obtained. It shown increase of heat transfer coefficient under boiling of nanofluid.

  20. Prediction of subcooled flow boiling characteristics using two-fluid Eulerian CFD model

    Energy Technology Data Exchange (ETDEWEB)

    Braz Filho, Francisco A.; Ribeiro, Guilherme B., E-mail: gbribeiro@ieav.cta.br; Caldeira, Alexandre D.

    2016-11-15

    Highlights: • CFD multiphase model is used to predict subcooled flow boiling characteristics. • Better agreement is achieved for higher saturation pressures. • Onset of nucleate boiling and saturated boiling are well predicted. • CFD multiphase model tends to underestimate the void fraction. • Factors were adjusted in order to improve the void fraction results. - Abstract: The present study concerns a detailed analysis of flow boiling phenomena under high pressure systems using a two-fluid Eulerian approach provided by a Computational Fluid Dynamics (CFD) solver. For this purpose, a vertical heated pipe made of stainless steel with an internal diameter of 15.4 mm was considered as the modeled domain. Two different uniform heat fluxes and three saturation pressures were applied to the channel wall, whereas water mass flux of 900 kg/m{sup 2} s was considered for all simulation cases. The model was validated against a set of experimental data and results have indicated a promising use of the CFD technique for estimation of the wall temperature, the liquid bulk temperature and the location of the departure of nucleate boiling. Changes in factors applied in the modeling of the interfacial heat transfer coefficient and bubble departure frequency were suggested, allowing a better prediction of the void fraction along the heated channel. The commercial CFD solver FLUENT 14.5 was used for the model implementation.

  1. Microbiological effectiveness and cost of boiling to disinfect drinking water in rural Vietnam.

    Science.gov (United States)

    Clasen, Thomas F; Thao, Do Hoang; Boisson, Sophie; Shipin, Oleg

    2008-06-15

    Despite certain shortcomings, boiling is still the most common means of treating water in the home and the benchmark against which alternative household-based disinfection and filtration methods must be measured. We assessed the microbiological effectiveness and cost of boiling among a vulnerable population relying on unimproved water sources and commonly practicing boiling as a means of disinfecting water. In a 12 week study among 50 households from a rural community in Vietnam, boiling was associated with a 97% reduction in geometric mean thermotolerant coliforms (TTCs) (p water, 37% of stored water samples from self-reported boilers met the WHO standard for safe drinking water (0 TTC/100 mL), and 38.3% fell within the low risk category (1--10 TTC/100 mL). Nevertheless, 60.5% of stored drinking water samples were positive for TTC, with 22.2% falling into the medium risk category (11--100 TTC/100 mL). The estimated cost of wood used to boil water was US$ 0.272 per month for wood collectors and US$ 1.68 per month for wood purchasers, representing approximately 0.48% to 1.04%, respectively, of the average monthly income of participating households.

  2. An investigation into the influence of different parameters on the onset of boiling in minichannels

    Directory of Open Access Journals (Sweden)

    Piasecka Magdalena

    2013-02-01

    Full Text Available The paper presents experimental studies on boiling heat transfer in rectangular minichannels. The investigations focus on the transition from single phase forced convection to nucleate boiling, i.e., in the zone of boiling incipience. The experiment has been carried out with FC-72, R-123 and R-11 at the Reynolds number below 4700, corresponding to mass flow rate range 95-710 kg/(m s. The main part of the test section is a minichannel of pre-set depth from 0.7 to 2 mm and width (20, 40 and 60 mm, with different spatial orientations from vertical to horizontal and 30% inclination angle adjustment. The objective of the paper includes the impact of selected parameters (liquid flow velocity, pressure and inlet liquid subcooling, channel dimensions and spatial orientation on the boiling incipience in minichannels. The investigations are intended to develop a correlation for the calculations of the Nusselt number under the conditions of boiling incipience in the minichannel as a function of changeable parameters.

  3. An investigation into the influence of different parameters on the onset of boiling in minichannels

    Science.gov (United States)

    Piasecka, Magdalena

    2013-02-01

    The paper presents experimental studies on boiling heat transfer in rectangular minichannels. The investigations focus on the transition from single phase forced convection to nucleate boiling, i.e., in the zone of boiling incipience. The experiment has been carried out with FC-72, R-123 and R-11 at the Reynolds number below 4700, corresponding to mass flow rate range 95-710 kg/(m s). The main part of the test section is a minichannel of pre-set depth from 0.7 to 2 mm and width (20, 40 and 60 mm), with different spatial orientations from vertical to horizontal and 30% inclination angle adjustment. The objective of the paper includes the impact of selected parameters (liquid flow velocity, pressure and inlet liquid subcooling, channel dimensions and spatial orientation) on the boiling incipience in minichannels. The investigations are intended to develop a correlation for the calculations of the Nusselt number under the conditions of boiling incipience in the minichannel as a function of changeable parameters.

  4. Design, Construction, and Qualification of a Microscale Heater Array for Use in Boiling Heat Transfer

    Science.gov (United States)

    Rule, T. D.; Kim, J.; Kalkur, T. S.

    1998-01-01

    Boiling heat transfer is an efficient means of heat transfer because a large amount of heat can be removed from a surface using a relatively small temperature difference between the surface and the bulk liquid. However, the mechanisms that govern boiling heat transfer are not well understood. Measurements of wall temperature and heat flux near the wall would add to the database of knowledge which is necessary to understand the mechanisms of nucleate boiling. A heater array has been developed which contains 96 heater elements within a 2.5 mm square area. The temperature of each heater element is held constant by an electronic control system similar to a hot-wire anemometer. The voltage that is being applied to each heater element can be measured and digitized using a high-speed A/D converter, and this digital information can be compiled into a series of heat-flux maps. Information for up to 10,000 heat flux maps can be obtained each second. The heater control system, the A/D system and the heater array construction are described in detail. Results are presented which show that this is an effective method of measuring the local heat flux during nucleate and transition boiling. Heat flux maps are obtained for pool boiling in FC-72 on a horizontal surface. Local heat flux variations are shown to be three to six times larger than variations in the spatially averaged heat flux.

  5. Computational Fluid Dynamic Simulation of Single Bubble Growth under High-Pressure Pool Boiling Conditions

    Directory of Open Access Journals (Sweden)

    Janani Murallidharan

    2016-08-01

    Full Text Available Component-scale modeling of boiling is predominantly based on the Eulerian–Eulerian two-fluid approach. Within this framework, wall boiling is accounted for via the Rensselaer Polytechnic Institute (RPI model and, within this model, the bubble is characterized using three main parameters: departure diameter (D, nucleation site density (N, and departure frequency (f. Typically, the magnitudes of these three parameters are obtained from empirical correlations. However, in recent years, efforts have been directed toward mechanistic modeling of the boiling process. Of the three parameters mentioned above, the departure diameter (D is least affected by the intrinsic uncertainties of the nucleate boiling process. This feature, along with its prominence within the RPI boiling model, has made it the primary candidate for mechanistic modeling ventures. Mechanistic modeling of D is mostly carried out through solving of force balance equations on the bubble. Forces incorporated in these equations are formulated as functions of the radius of the bubble and have been developed for, and applied to, low-pressure conditions only. Conversely, for high-pressure conditions, no mechanistic information is available regarding the growth rates of bubbles and the forces acting on them. In this study, we use direct numerical simulation coupled with an interface tracking method to simulate bubble growth under high (up to 45 bar pressure, to obtain the kind of mechanistic information required for an RPI-type approach. In this study, we compare the resulting bubble growth rate curves with predictions made with existing experimental data.

  6. Pool boiling of nanofluids on rough and porous coated tubes: experimental and correlation

    Directory of Open Access Journals (Sweden)

    Cieśliński Janusz T.

    2014-06-01

    Full Text Available The paper deals with pool boiling of water-Al2O3 and water- Cu nanofluids on rough and porous coated horizontal tubes. Commercially available stainless steel tubes having 10 mm outside diameter and 0.6 mm wall thickness were used to fabricate the test heater. The tube surface was roughed with emery paper 360 or polished with abrasive compound. Aluminium porous coatings of 0.15 mm thick with porosity of about 40% were produced by plasma spraying. The experiments were conducted under different absolute operating pressures, i.e., 200, 100, and 10 kPa. Nanoparticles were tested at the concentration of 0.01, 0.1, and 1% by weight. Ultrasonic vibration was used in order to stabilize the dispersion of the nanoparticles. It was observed that independent of operating pressure and roughness of the stainless steel tubes addition of even small amount of nanoparticles augments heat transfer in comparison to boiling of distilled water. Contrary to rough tubes boiling heat transfer coefficient of tested nanofluids on porous coated tubes was lower compared to that for distilled water while boiling on porous coated tubes. A correlation equation for prediction of the average heat transfer coefficient during boiling of nanofluids on smooth, rough and porous coated tubes is proposed. The correlation includes all tested variables in dimensionless form and is valid for low heat flux, i.e., below 100 kW/m2.

  7. Nanocomposite films

    Science.gov (United States)

    Mitlin, David; , Ophus, Colin; Evoy, Stephane; Radmilovic, Velimir; Mohammadi, Reza; Westra, Ken; Nelson-Fitzpatrick, Nathaniel; Lee, Zonghoon

    2010-07-20

    A thin-film composition of nanocrystal molybdenum in an amorphous metallic matrix may be formed by co-sputtering Mo with aluminum or nickel. NEMS cantilevers may be formed from the film. The films exhibit high nanoindentation hardness and a reduction in roughness and intrinsic stress, while maintaining resistivity in the metallic range.

  8. Evolution of steam-water flow structure under subcooled water boiling at smooth and structured heating surfaces

    Science.gov (United States)

    Vasiliev, N. V.; Zeigarnik, Yu A.; Khodakov, K. A.

    2017-11-01

    Experimentally studying of subcooled water boiling in rectangular channel electrically heated from one side was conducted. Flat surfaces, both smooth and coated by microarc oxidation technology, were used as heating surfaces. The tests were conducted at atmospheric pressure in the range of mass flow rate from 650 to 1300 kg/(m2 s) and water subcooling relative to saturation temperature from 23 to 75 °C. Using high-speed filming a change in the two-phase flow structure and its statistic characteristics (nucleation sites density, vapor bubble distribution by size, etc.) were studied. With an increase in the heat flux density (with the mass flow rate and subcooling being the same) and amount and size of the vapor bubbles increased also. At a relatively high heat flux density, non-spherical vapor agglomerates appeared at the heating surface as a result of coalescence of small bubbles. They originated in chaotic manner in arbitrary points of the heating surface and then after random evolution in form and size collapsed. The agglomerate size reached several millimeters and their duration of life was several milliseconds. After formation of large vapor agglomerates, with a further small increase in heat flux density a burnout of the heating surface occurred. In most cases the same effect took place if the large agglomerates were retained for several minutes.

  9. Pseudo-acne fulminans associated with oral isotretinoin*

    Science.gov (United States)

    Grando, Luciana Rosa; Leite, Oriete Gerin; Cestari, Tania Ferreira

    2014-01-01

    Acne fulminans is a rare and serious condition characterized by the sudden onset of nodular and ulcerative acne lesions associated with systemic symptoms. It has been recognized a subset of patients with a sudden worsening of acne, often during treatment with oral isotretinoin, but without the strong presence of systemic involvement. Recognized by some authors as "pseudo-acne fulminans" or " acne fulminans sine fulminans," we report a case with these features in order to draw attention to the recognition and early management of this manifestation. PMID:25054758

  10. [Hemopyrrollactamuria (HPU); from spots to pseudo-disease].

    Science.gov (United States)

    van der Meer, J W; van de Kerkhof, R; The, G K; Boers, G H

    2003-09-06

    In recent years, patients in the Netherlands confront their doctors with the diagnosis 'haemopyrollactamuria' (HPU), based on the presence of the haemopyrrollactam complex in their urine. The diagnosis is made by a commercial laboratory in the Netherlands (www.keac.nl). We have not been able to find peer-reviewed scientific literature on this metabolic disease. The haemopyrrollactam complex represents the so-called mauve spot, which was the subject of much controversy in schizophrenia research in the previous century. Reviewing all of the available data, we feel that HPU should be classified as a pseudo-disease.

  11. Coherent imaging with pseudo-thermal incoherent light

    DEFF Research Database (Denmark)

    Gatti, A.; Bache, Morten; Magatti, D.

    2006-01-01

    We investigate experimentally fundamental properties of coherent ghost imaging using spatially incoherent beams generated from a pseudo-thermal source. A complementarity between the coher- ence of the beams and the correlation between them is demonstrated by showing a complementarity between ghost...... diffraction and ordinary diffraction patterns. In order for the ghost imaging scheme to work it is therefore crucial to have incoherent beams. The visibility of the information is shown for the ghost image to become better as the object size relative to the speckle size is decreased, and therefore...

  12. Pseudo-compressibility methods for the incompressible flow equations

    Science.gov (United States)

    Turkel, Eli; Arnone, A.

    1993-01-01

    Preconditioning methods to accelerate convergence to a steady state for the incompressible fluid dynamics equations are considered. The analysis relies on the inviscid equations. The preconditioning consists of a matrix multiplying the time derivatives. Thus the steady state of the preconditioned system is the same as the steady state of the original system. The method is compared to other types of pseudo-compressibility. For finite difference methods preconditioning can change and improve the steady state solutions. An application to viscous flow around a cascade with a non-periodic mesh is presented.

  13. Pseudo inputs for pairwise learning with Gaussian processes

    DEFF Research Database (Denmark)

    Nielsen, Jens Brehm; Jensen, Bjørn Sand; Larsen, Jan

    2012-01-01

    is based on a classical pairwise probit likelihood imposed with a Gaussian process prior. While extremely flexible, this non-parametric method struggles with an inconvenient O(n3) scaling in terms of the n input instances which limits the method only to smaller problems. To overcome this, we derive...... a specific sparse extension of the classical pairwise likelihood using the pseudo-input formulation. The behavior of the proposed extension is demonstrated on a toy example and on two real-world data sets which outlines the potential gain and pitfalls of the approach. Finally, we discuss the relation...

  14. Displaced vertices from pseudo-Dirac dark matter

    Science.gov (United States)

    Davoli, Alessandro; De Simone, Andrea; Jacques, Thomas; Sanz, Verónica

    2017-11-01

    Displaced vertices are relatively unusual signatures for dark matter searches at the LHC. We revisit the model of pseudo-Dirac dark matter (pDDM), which can accommodate the correct relic density, evade direct detection constraints, and generically provide observable collider signatures in the form of displaced vertices. We use this model as a benchmark to illustrate the general techniques involved in the analysis, the complementarity between monojet and displaced vertex searches, and provide a comprehensive study of the current bounds and prospective reach.

  15. Age bimodality in the central region of pseudo-bulges in S0 galaxies

    Science.gov (United States)

    Mishra, Preetish K.; Barway, Sudhanshu; Wadadekar, Yogesh

    2017-11-01

    We present evidence for bimodal stellar age distribution of pseudo-bulges of S0 galaxies as probed by the Dn(4000) index. We do not observe any bimodality in age distribution for pseudo-bulges in spiral galaxies. Our sample is flux limited and contains 2067 S0 and 2630 spiral galaxies drawn from the Sloan Digital Sky Survey. We identify pseudo-bulges in S0 and spiral galaxies, based on the position of the bulge on the Kormendy diagram and their central velocity dispersion. Dividing the pseudo-bulges of S0 galaxies into those containing old and young stellar populations, we study the connection between global star formation and pseudo-bulge age on the u - r colour-mass diagram. We find that most old pseudo-bulges are hosted by passive galaxies while majority of young bulges are hosted by galaxies that are star forming. Dividing our sample of S0 galaxies into early-type S0s and S0/a galaxies, we find that old pseudo-bulges are mainly hosted by early-type S0 galaxies while most of the pseudo-bulges in S0/a galaxies are young. We speculate that morphology plays a strong role in quenching of star formation in the disc of these S0 galaxies, which stops the growth of pseudo-bulges, giving rise to old pseudo-bulges and the observed age bimodality.

  16. Modeling and measurement of boiling point elevation during water vaporization from aqueous urea for SCR applications

    Energy Technology Data Exchange (ETDEWEB)

    Dan, Ho Jin; Lee, Joon Sik [Seoul National University, Seoul (Korea, Republic of)

    2016-03-15

    Understanding of water vaporization is the first step to anticipate the conversion process of urea into ammonia in the exhaust stream. As aqueous urea is a mixture and the urea in the mixture acts as a non-volatile solute, its colligative properties should be considered during water vaporization. The elevation of boiling point for urea water solution is measured with respect to urea mole fraction. With the boiling-point elevation relation, a model for water vaporization is proposed underlining the correction of the heat of vaporization of water in the urea water mixture due to the enthalpy of urea dissolution in water. The model is verified by the experiments of water vaporization as well. Finally, the water vaporization model is applied to the water vaporization of aqueous urea droplets. It is shown that urea decomposition can begin before water evaporation finishes due to the boiling-point elevation.

  17. Pool boiling of distilled water over tube bundle with variable heat flux

    Science.gov (United States)

    Swain, Abhilas; Mohanty, Rajiva Lochan; Das, Mihir Kumar

    2017-08-01

    The experimental investigation of saturated pool boiling heat transfer of distilled water over plain tube bundle, under uniform and varying heat flux condition along the height are presented in this article. Experiments are carried out under various heat flux configurations applied to rows of tube bundles and pitch distance to diameter ratios of 1.25, 1.6 and 1.95. The wall superheats and pool boiling heat transfer coefficients over individual rows are determined. The pool boiling heat transfer coefficients for variable heat flux and uniform heat flux conditions are compared. The results indicate that the bundle effect is found to exist for uniform as well as variable heat flux under all operating conditions in the present investigation. The variable heat flux resulted in range of wall superheat being highest for decreasing heat flux from bottom to top and lowest for increasing heat flux from bottom to top.

  18. Flow Boiling Heat Transfer to Lithium Bromide Aqueous Solution in Subcooled Region

    Science.gov (United States)

    Kaji, Masao; Furukawa, Masahiro; Nishizumi, Takeharu; Ozaki, Shinji; Sekoguchi, Kotohiko

    A theoretical prediction model of the boiling heat transfer coefficient in the subcooled region for water and lithium bromide aqueous solution flowing in a rectangular channel is proposed. In the present heat transfer model, a heat flux is assumed to consist of both the forced convective and the boiling effect components. The forced convective component is evaluated from the empirical correlation of convective heat transfer coefficient for single-phase flow considering the effect of increase of liquid velocity due to net vapor generation. Empirical correlations for determining the heat flux due to the boiling effect and the quality at the onset point of net vapor generation are obtained from the data presented in the first report1). Agreement between the present theoretical prediction and the experimental data is satisfactorily good both for water and lithium bromide aqueous solution.

  19. Simulation of boiling pools with internal heat sources by gas injection. [LMFBR core meltdown

    Energy Technology Data Exchange (ETDEWEB)

    Luk, A.C.H.; Ganguli, A.; Bankoff, S.G.

    1977-07-29

    Heat transfer from the sides and bottom of an open non-boiling liquid pool with spatially uniform internal gas injection was studied experimentally, both in transient and in steady state. The results were compared with experimental data for a boiling pool without permanent gas injection undertaken at Argonne National Laboratory. Typical Nusselt number versus Reynolds number plots showed that heat transfer rates were much higher in the gassy pool due to more efficient circulation. A correction was applied to estimate the surface evaporation effect under boiling conditions. Bubble size and distribution effects controlled the heat transfer rates. Vertical void fraction profiles were inferred from local static pressure measurements. A modified Grashof number, in terms of the average void fraction, was also used to correlate the data for horizontal heat flow. The bottom and side heat loss rates were about equal, which would indicate that the pool might retain its shape as it sinks into the support material.

  20. An improved mechanistic critical heat flux model for subcooled flow boiling

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Young Min [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1997-12-31

    Based on the bubble coalescence adjacent to the heated wall as a flow structure for CHF condition, Chang and Lee developed a mechanistic critical heat flux (CHF) model for subcooled flow boiling. In this paper, improvements of Chang-Lee model are implemented with more solid theoretical bases for subcooled and low-quality flow boiling in tubes. Nedderman-Shearer`s equations for the skin friction factor and universal velocity profile models are employed. Slip effect of movable bubbly layer is implemented to improve the predictability of low mass flow. Also, mechanistic subcooled flow boiling model is used to predict the flow quality and void fraction. The performance of the present model is verified using the KAIST CHF database of water in uniformly heated tubes. It is found that the present model can give a satisfactory agreement with experimental data within less than 9% RMS error. 9 refs., 5 figs. (Author)

  1. Predictors of Drinking Water Boiling and Bottled Water Consumption in Rural China: A Hierarchical Modeling Approach.

    Science.gov (United States)

    Cohen, Alasdair; Zhang, Qi; Luo, Qing; Tao, Yong; Colford, John M; Ray, Isha

    2017-06-20

    Approximately two billion people drink unsafe water. Boiling is the most commonly used household water treatment (HWT) method globally and in China. HWT can make water safer, but sustained adoption is rare and bottled water consumption is growing. To successfully promote HWT, an understanding of associated socioeconomic factors is critical. We collected survey data and water samples from 450 rural households in Guangxi Province, China. Covariates were grouped into blocks to hierarchically construct modified Poisson models and estimate risk ratios (RR) associated with boiling methods, bottled water, and untreated water. Female-headed households were most likely to boil (RR = 1.36, p China's economy continues to grow then bottled water use will increase.

  2. Starch characterization in seven raw, boiled and roasted chestnuts (Castanea sativa Mill.) cultivars from Portugal.

    Science.gov (United States)

    Silva, A P; Oliveira, I; Silva, M E; Guedes, C M; Borges, O; Magalhães, B; Gonçalves, B

    2016-01-01

    Changes occurring in seven chestnut (Castanea sativa sp.) cultivars, caused by boiling and roasting, on starch content, cell and starch granules dimension were evaluated, and morphological changes were characterized by scanning electron microscopy. Three clear patterns of variation were detected after processing, namely: i) decrease of starch content with processing; ii) starch increase with the applied treatments; iii) increase of starch with boiling and decrease with roasting. Starch granules of raw chestnuts presented round, oval or elliptical form, external smooth surface and eccentric hilum, with rather ellipsoid-shaped growth rings. Processing resulted in modifications of the granules, with fusion of individual granules, and gelatinization taking place with the formation of elongated clusters. The present results indicate that boiling and roasting, besides changing the starch content of chestnut, causes important modifications in the starch granules, which can affect the sensory, rheological and chemical characteristics of chestnuts.

  3. Enhancement of critical heat flux in nucleate boiling of nanofluids: a state-of-art review

    Directory of Open Access Journals (Sweden)

    Kim Hyungdae

    2011-01-01

    Full Text Available Abstract Nanofluids (suspensions of nanometer-sized particles in base fluids have recently been shown to have nucleate boiling critical heat flux (CHF far superior to that of the pure base fluid. Over the past decade, numerous experimental and analytical studies on the nucleate boiling CHF of nanofluids have been conducted. The purpose of this article is to provide an exhaustive review of these studies. The characteristics of CHF enhancement in nanofluids are systemically presented according to the effects of the primary boiling parameters. Research efforts to identify the effects of nanoparticles underlying irregular enhancement phenomena of CHF in nanofluids are then presented. Also, attempts to explain the physical mechanism based on available CHF theories are described. Finally, future research needs are identified.

  4. Prediction of the critical heat flux for saturated upward flow boiling water in vertical narrow rectangular channels

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Gil Sik, E-mail: choigs@kaist.ac.kr; Chang, Soon Heung; Jeong, Yong Hoon

    2016-07-15

    A study, on the theoretical method to predict the critical heat flux (CHF) of saturated upward flow boiling water in vertical narrow rectangular channels, has been conducted. For the assessment of this CHF prediction method, 608 experimental data were selected from the previous researches, in which the heated sections were uniformly heated from both wide surfaces under the high pressure condition over 41 bar. For this purpose, representative previous liquid film dryout (LFD) models for circular channels were reviewed by using 6058 points from the KAIST CHF data bank. This shows that it is reasonable to define the initial condition of quality and entrainment fraction at onset of annular flow (OAF) as the transition to annular flow regime and the equilibrium value, respectively, and the prediction error of the LFD model is dependent on the accuracy of the constitutive equations of droplet deposition and entrainment. In the modified Levy model, the CHF data are predicted with standard deviation (SD) of 14.0% and root mean square error (RMSE) of 14.1%. Meanwhile, in the present LFD model, which is based on the constitutive equations developed by Okawa et al., the entire data are calculated with SD of 17.1% and RMSE of 17.3%. Because of its qualitative prediction trend and universal calculation convergence, the present model was finally selected as the best LFD model to predict the CHF for narrow rectangular channels. For the assessment of the present LFD model for narrow rectangular channels, effective 284 data were selected. By using the present LFD model, these data are predicted with RMSE of 22.9% with the dryout criterion of zero-liquid film flow, but RMSE of 18.7% with rivulet formation model. This shows that the prediction error of the present LFD model for narrow rectangular channels is similar with that for circular channels.

  5. Numerical Study on Bubble Behaviour and Heat Transfer Characteristics of Subcooled Pool Boiling Based on Non-Empirical Boiling and Condensation Model

    Directory of Open Access Journals (Sweden)

    Y. Ose

    2014-12-01

    Full Text Available In this study, the transient three-dimensional numerical simulations based on the MARS (Multi-interface Advection and Reconstruction Solver with the non-empirical boiling and condensation model have been conducted for isolated boiling bubble behaviour in a subcooled pool. The effects of the wettability on the heating surface for the subcooled bubble departure behaviour were investigated. The numerical results showed in very good agreement with the experimental results. Furthermore, resulting from the wall heat flux evaluation, it was found that the wall heat flux near the contact line at the bottom of the bubble just before the bubble departing from the heating surface increases with increases of the degree of subcooling.

  6. Natural convection heat transfer characteristics of the molten metal pool with solidification by boiling coolant

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jae Seon; Suh, Kune Yull; Chung, Chang Hyun [Seoul National University, Seoul (Korea, Republic of); Paark, Rae Joon; Kim, Sang Baik [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    This paper presents results of experimental studies on the heat transfer and solidification of the molten metal pool with overlying coolant with boiling. The metal pool is heated from the bottom surface and coolant is injected onto the molten metal pool. Ad a result, the crust, which is a solidified layer, may form at the top of the molten metal pool. Heat transfer is accomplished by a conjugate mechanism, which consists of the natural convection of the molten metal pool, the conduction in the crust layer and the convective boiling heat transfer in the coolant. This work examines the crust formation and the heat transfer rate on the molten metal pool with boiling coolant. The simulant molten pool material is tin (Sn) with the melting temperature of 232 deg C. Demineralized water is used as the working coolant. The crust layer thickness was ostensibly varied by the heated bottom surface temperature of the test section, but not much affected by the coolant injection rate. The correlation between the Nusselt number and the Rayleigh number in the molten metal pool region of this study is compared against the crust formation experiment without coolant boiling and the literature correlations. The present experimental results are higher than those from the experiment without coolant boiling, but show general agreement with the Eckert correlation, with some deviations in the high and low ends of the Rayleigh number. This discrepancy is currently attributed to concurrent rapid boiling of the coolant on top of the metal layer. 10 refs., 4 figs., 1 tab. (Author)

  7. Bench-scale screening tests for a boiling sodium-potassium alloy solar receiver

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, J.B.; Moss, T.A.

    1993-06-01

    Bench-scale tests were carried out in support of the design of a second-generation 75-kW{sub t} reflux pool-boiler solar receiver. The receiver will be made from Haynes Alloy 230 and will contain the sodium-potassium alloy NaK-78. The bench-scale tests used quartz-lamp-heated boilers to screen candidate boiling-stabilization materials and methods at temperatures up to 750{degree}C. Candidates that provided stable boiling were tested for hot-restart behavior. Poor stability was obtained with single 1/4-inch diameter patches of powdered metal hot-press-sintered onto the wetted side of the heat-input area. Laser-drilled and electric-discharge-machined cavities in the heated surface also performed poorly. Small additions of xenon, and heated-surface tilt out of the vertical dramatically improved poor boiling stability; additions of helium or oxygen did not. The most stable boiling was obtained when the entire heat-input area was covered by a powdered-metal coating. The effect of heated-area size was assessed for one coating: at low incident fluxes, when even this coating performed poorly, increasing the heated-area size markedly improved boiling stability. Good hot-restart behavior was not observed with any candidate, although results were significantly better with added xenon in a boiler shortened from 3 to 2 feet. In addition to the screening tests, flash-radiography imaging of metal-vapor bubbles during boiling was attempted. Contrary to the Cole-Rohsenow correlation, these bubble-size estimates did not vary with pressure; instead they were constant, consistent with the only other alkali metal measurements, but about 1/2 their size.

  8. Analysis and Measurement of Bubble Dynamics and Associated Flow Field in Subcooled Nucleate Boiling Flows

    Energy Technology Data Exchange (ETDEWEB)

    Barclay G. Jones

    2008-10-01

    In recent years, subooled nucleate boiling (SNB) has attrcted expanding research interest owing to the emergence of axial offset anomaly (AOA) or crud-induced power shigt (CIPS) in many operating US PWRs, which is an unexpected deviation in the core axial power distribution from the predicted power curves. Research indicates that the formation of the crud, which directly leads to AOA phenomena, results from the presence of the subcooled nucleate boiling, and is especially realted to bubble motion occurring in the core region.

  9. Forced bulk boiling at high heat fluxes; Erzwungenes Blasensieden bei hohen Waermestromdichten

    Energy Technology Data Exchange (ETDEWEB)

    Knipping, Tobias; Humpfer, Frank; Arnemann, Michael [Hochschule Karlsruhe - Technik und Wirtschaft (HsKA) (Germany). Fakultaet fuer Maschinenbau und Mechatronik fuer Kaelte-, Klima- und Umwelttechnik (IKKU)

    2013-05-15

    The influence of very high heat flux densities (10{sup 5} to 10{sup 7} W/m{sup 2}) on the boiling behavior of R404A is investigated. By using a new evaporator design it is possible to change the evaporating effects even at these high heat flux densities to bulk boiling. This paper focuses on the experimental analysis of the new evaporator by varying the parameters geometry, mass flux, subcooling and fluid velocity. The results show that fluid velocity, mass flux and geometry have a high influence on the transferred heat-flow, while the subcooling of the liquid phase only has a small effect. (orig.)

  10. An electrical simulator of a nuclear fuel rod cooled by nucleate boiling

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Antonio Carlos Lopes da [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)], e-mail: aclc@cdtn.br; Machado, Luiz; Koury, Ricardo Nicolau Nassar [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Mecanica], e-mail: luizm@demec.ufmg.br; Bonjour, Jocelyn [CETHIL, UMR5008, CNRS, INSA-Lyon (France)], e-mail: jocelyn.bonjour@insa-lyon.fr; Passos, Julio Cesar [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica. LEPTEN/Boiling], e-mail: jpassos@emc.ufsc.br

    2009-07-01

    This study investigates an electrical heated test section designed to simulate a nuclear fuel rod. This simulator comprises a stainless steel vertical tube, with length and outside diameter of 600 mm and 10 mm, respectively, inside which there is a high power electrical resistor. The heat generated is removed by means of enhanced confined subcooled nucleate boiling of water in an annular space containing 153 small metal inclined discs. The tests were performed under electrical power and pressure up to 48 kW and 40 bar, respectively. The results show that the experimental boiling heat transfer coefficients are in good agreement with those calculated using the Jens-Lottes correlation. (author)

  11. Propagation of Local Bubble Parameters of Subcooled Boiling Flow in a Pressurized Vertical Annulus Channel

    Energy Technology Data Exchange (ETDEWEB)

    Chu, In-Cheol; Lee, Seung Jun; Youn, Young Jung; Park, Jong Kuk; Choi, Hae Seob; Euh, Dong Jin [KAERI, Daejeon (Korea, Republic of)

    2015-05-15

    CMFD (Computation Multi-Fluid Dynamics) tools have been being developed to simulate two-phase flow safety problems in nuclear reactor, including the precise prediction of local bubble parameters in subcooled boiling flow. However, a lot of complicated phenomena are encountered in the subcooled boiling flow such as bubble nucleation and departure, interfacial drag of bubbles, lateral migration of bubbles, bubble coalescence and break-up, and condensation of bubbles, and the constitutive models for these phenomena are not yet complete. As a result, it is a difficult task to predict the radial profile of bubble parameters and its propagation along the flow direction. Several experiments were performed to measure the local bubble parameters for the validation of the CMFD code analysis and improvement of the constitutive models of the subcooled boiling flow, and to enhance the fundamental understanding on the subcooled boiling flow. The information on the propagation of the local flow parameters along the flow direction was not provided because the measurements were conducted at the fixed elevation. In SUBO experiments, the radial profiles of local bubble parameters, liquid velocity and temperature were obtained for steam-water subcooled boiling flow in a vertical annulus. The local flow parameters were measured at six elevations along the flow direction. The pressure was in the range of 0.15 to 0.2 MPa. We have launched an experimental program to investigate quantify the local subcooled boiling flow structure under elevated pressure condition in order to provide high precision experimental data for thorough validation of up-to-date CMFD codes. In the present study, the first set of experimental data on the propagation of the radial profile of the bubble parameters was obtained for the subcooled boiling flow of R-134a in a pressurized vertical annulus channel. An experimental program was launched for an in-depth investigation of a subcooled boiling flow in an elevated

  12. CFD SIMULATION OF UPWARD SUBCOOLED BOILING FLOW OF FREON R12

    Directory of Open Access Journals (Sweden)

    Tomas Romsy

    2016-12-01

    Full Text Available Subcooled flow boiling under forced convection occurs in many industrial applications of purpose to maximize heat removal from the heat source by the very large heat transfer coefficient. This work deals with CFD simulations of the subcooled flow boiling of refrigerant R12 solved by code ANSYS FLUENT r16. The main objective of this paper is verification of used numerical settings on relevant experiments performed on DEBORA test facility. Also comparisons with previously provided simulation on NRI Rez are presented. Data outputs from this work are basis to subsequent calculations of steam-water mixture cooling of Pb-Li eutectic.

  13. WCS120 protein family and proteins soluble upon boiling in cold-acclimated winter wheat

    DEFF Research Database (Denmark)

    Vitamvas, P.; Saalbach, Gerhard; Prasil, I.T.

    2007-01-01

    The amount of proteins soluble upon boiling (especially WCS120 proteins) and the ability to develop frost tolerance (FT) after cold acclimation was studied in two frost-tolerant winter wheat cultivars, Mironovskaya 808 and Bezostaya 1. Protein get Not analysis, mass spectrometry (MS) and image...... analysis of total sample of proteins soluble upon boiling showed seven COR proteins in the CA samples and only three COR proteins in the NA samples of cultivar Mironovskaya 808 (MIR). In conclusion, the Level of the accumulation of WCS120, WCS66 and WCS40 distinguished our two frost-tolerant winter wheat...

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

    DEFF Research Database (Denmark)

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

    2016-01-01

    Response surface methodology is used to investigate an active method for flow boiling heat transfer enhancement by means of fluid flow pulsation. The flow pulsations are introduced by a flow modulating expansion device and compared with the baseline continuous flow provided by a stepper-motor exp......Response surface methodology is used to investigate an active method for flow boiling heat transfer enhancement by means of fluid flow pulsation. The flow pulsations are introduced by a flow modulating expansion device and compared with the baseline continuous flow provided by a stepper...

  15. Development of a new simulation code for evaluation of criticality transients involving fissile solution boiling

    Energy Technology Data Exchange (ETDEWEB)

    Basoglu, Benan; Yamamoto, Toshihiro; Okuno, Hiroshi; Nomura, Yasushi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    In this work, we report on the development of a new computer code named TRACE for predicting the excursion characteristics of criticality excursions involving fissile solutions. TRACE employs point neutronics coupled with simple thermal-hydraulics. The temperature, the radiolytic gas effects, and the boiling phenomena are estimated using the transient heat conduction equation, a lumped-parameter energy model, and a simple boiling model, respectively. To evaluate the model, we compared our results with the results of CRAC experiments. The agreement in these comparisons is quite satisfactory. (author)

  16. Evaporation for Lithium Bromide Aqueous Solution in a Falling Film Heater under Reduced Pressures

    Science.gov (United States)

    Matsuda, Akira; Ide, Tetsuo; Yukino, Keiji

    Experiments on evaporation for water and lithium bromide (LiBr) aqueous solution were made in a externally heated wetted-wall column under reduced pressures. For water, evaporation rate increased slightly as feed rate decreased. The heat transfer coefficients of falling film agreed with those for filmwise condensation. For LiBr solution, evaporation rate decreased and outlet temperature of LiBr solution increased as feed rate decreased. The equations of continuity, diffusion and energy which assume that only water moves to the surface and LiBr doesn't move through falling film of LiBr solution were solved numerically. Calculated values of evaporation rate and outlet temperature of solution agreed with experimental results. The results of this work were compared with pool boiling data reported previously, and it was shown that falling film heater is superior to pool boiling heater concerning heat transfer.

  17. Pseudo-Stem Banana Fibers: Characterization and Chromium Removal

    Directory of Open Access Journals (Sweden)

    Helena Becker

    2013-11-01

    Full Text Available In this work, pseudo-stems of the banana tree were collected, characterized and used as adsorbent materials for the removal of the chromium ions from aqueous solution. The characterization of pseudo-stems by FTIR suggests the presence of cellulose, hemicellulose and lignin. The predominant groups were carbonyls (0.312 ± 0.010 mmol g–1 adsorbent, phenols (0.237 ± 0.021 mmol g–1 adsorbent, lactones (0.041 ± 0.003 mmol g–1 adsorbent and basic groups (0.096 ± 0.006 mmol g–1 adsorbent. The textural propriety of the adsorbent, surface area, pore volume and pore diameter were found to be 0.383 m2 g–1, 0.003525 cm3 g–1 and 368.3 Å, respectively. The pHpzc value was found 7.5 and so the adsorption assays of chromium removal from solution were more efficiently at acidic pH values. The experiments show that approximately 95% and 78% of the Cr (VI was removed from solution by untreated and treated fiber, respectively, in 300 minutes of the contact time.

  18. Pseudo-homophony in non-native listening

    Science.gov (United States)

    Cutler, Anne; Otake, Takashi

    2004-05-01

    Pseudo-homophony may result when non-native listeners cannot distinguish phonemic contrasts. Thus Dutch listeners have difficulty distinguishing the vowels of English cattle versus kettle, because this contrast is subsumed by a single Dutch vowel category; in consequence, both words may be activated whenever either is heard. A lexical decision study in English explored this phenomenon by testing for repetition priming. The materials contained among 340 items 18 pairs such as cattle/kettle, i.e., contrasting only in those vowels, and 18 pairs contrasting only in r/l (e.g., right/light). These materials, spoken by a native American English speaker, were presented to fluent non-native speakers of English, 48 Dutch Nijmegen University students, and 48 Japanese Dokkyo University students; the listeners performed lexical decision on each spoken item, and response time was measured. Dutch listeners responded significantly faster to one member of a cattle/kettle pair after having heard the other member earlier in the list (compared with having heard a control word), suggesting that both words had been activated whichever had been heard. Japanese listeners, however, showed no such priming for cattle/kettle words, but did show repetition priming across r/l pairs such as right/light. Non-native listeners' phonemic discrimination difficulties thus generate pseudo-homophony.

  19. PRIMITIVE MATRICES AND GENERATORS OF PSEUDO RANDOM SEQUENCES OF GALOIS

    Directory of Open Access Journals (Sweden)

    A. Beletsky

    2014-04-01

    Full Text Available In theory and practice of information cryptographic protection one of the key problems is the forming a binary pseudo-random sequences (PRS with a maximum length with acceptable statistical characteristics. PRS generators are usually implemented by linear shift register (LSR of maximum period with linear feedback [1]. In this paper we extend the concept of LSR, assuming that each of its rank (memory cell can be in one of the following condition. Let’s call such registers “generalized linear shift register.” The research goal is to develop algorithms for constructing Galois and Fibonacci generalized matrix of n-order over the field , which uniquely determined both the structure of corresponding generalized of n-order LSR maximal period, and formed on their basis Galois PRS generators of maximum length. Thus the article presents the questions of formation the primitive generalized Fibonacci and Galois arbitrary order matrix over the prime field . The synthesis of matrices is based on the use of irreducible polynomials of degree and primitive elements of the extended field generated by polynomial. The constructing methods of Galois and Fibonacci conjugated primitive matrices are suggested. The using possibilities of such matrices in solving the problem of constructing generalized generators of Galois pseudo-random sequences are discussed.

  20. Pseudo-creep in Shape Memory Alloy Wires and Sheets

    Science.gov (United States)

    Russalian, V. R.; Bhattacharyya, A.

    2017-10-01

    Interruption of loading during reorientation and isothermal pseudoelasticity in shape memory alloys with a strain arrest ( i.e., holding strain constant) results in a time-dependent evolution in stress or with a stress arrest ( i.e., holding stress constant) results in a time-dependent evolution in strain. This phenomenon, which we term as pseudo-creep, is similar to what was reported in the literature three decades ago for some traditional metallic materials undergoing plastic deformation. In a previous communication, we reported strain arrest of isothermal pseudoelastic loading, isothermal pseudoelastic unloading, and reorientation in NiTi wires as well as a rate-independent phase diagram. In this paper, we provide experimental results of the pseudo-creep phenomenon during stress arrest of isothermal pseudoelasticity and reorientation in NiTi wires as well as strain arrest of isothermal pseudoelasticity and reorientation in NiTi sheets. Stress arrest in NiTi wires accompanied by strain accumulation or recovery is studied using the technique of multi-video extensometry. The experimental results were used to estimate the amount of mechanical energy needed to evolve the wire from one microstructural state to another during isothermal pseudoelastic deformation and the difference in energies between the initial and the final rest state between which the aforementioned evolution has occurred.

  1. Pseudo-Finslerian Space-Times and Multirefringence

    Science.gov (United States)

    Skákala, Jozef; Visser, Matt

    Ongoing searches for a quantum theory of gravity have repeatedly led to the suggestion that space-time might ultimately be anisotropic (Finsler-like) and/or exhibit multirefringence (multiple signal cones). Multiple (and even anisotropic) signal cones can be easily dealt with in a unified manner, by writing down a single Fresnel equation to simultaneously encode all signal cones in an even-handed manner. Once one gets off the signal cone and attempts to construct a full multirefringent space-time metric the situation becomes more problematic. In the multirefringent case we shall report a significant no-go result: in multirefringent models there is no simple or compelling way to construct any unifying notion of pseudo-Finsler space-time metric, different from a monorefringenent model, where the signal cone structure plus a conformal factor completely specifies the full pseudo-Riemannian metric. To throw some light on this situation we use an analog model where both anisotropy and multirefringence occur simultaneously: biaxial birefringent crystal. But the significance of our results extends beyond the optical framework in which (purely for pedagogical reasons) we are working, and has implications for any attempt at introducing multirefringence and intrinsic anisotropies to any model of quantum gravity that has a low energy manifold-like limit.

  2. Existence of pseudo almost periodic solutions for a class of partial functional differential equations

    Directory of Open Access Journals (Sweden)

    Hui-Sheng Ding

    2013-04-01

    Full Text Available In this paper, we first introduce a new class of pseudo almost periodic type functions and investigate some properties of pseudo almost periodic type functions; and then we discuss the existence of pseudo almost periodic solutions to the class of abstract partial functional differential equations $x'(t=Ax(t+f(t,x_t$ with finite delay in a Banach space X.

  3. ANALYSIS OF THE CHEMICAL COMPOSITION AND MORPHOLOGICAL STRUCTURE OF BANANA PSEUDO-STEM

    OpenAIRE

    Kun Li; Shiyu Fu; Huaiyu Zhan; Yao Zhan; Lucian A. Lucia

    2010-01-01

    An analysis of the chemical composition and anatomical structure of banana pseudo-stem was carried out using Light Microscopy (LM), Scanning Electron Microscopy (SEM), and Confocal Laser Scanning Microscopy (CLSM). The chemical analysis indicated there is a high holocellulose content and low lignin content in banana pseudo-stem compared with some other non-wood fiber resources. These results demonstrate that the banana pseudo-stem has potential value for pulping. In addition, we report for th...

  4. Neutrosophic Regular Filters and Fuzzy Regular Filters in Pseudo-BCI Algebras

    Directory of Open Access Journals (Sweden)

    Xiaohong Zhang

    2017-09-01

    Full Text Available Neutrosophic set is a new mathematical tool for handling problems involving imprecise, indeterminacy and inconsistent data. Pseudo-BCI algebra is a kind of non-classical logic algebra in close connection with various non-commutative fuzzy logics. Recently, we applied neutrosophic set theory to pseudo-BCI algebras. In this paper, we study neutrosophic filters in pseudo-BCI algebras.

  5. Continuous curves of nonmetric pseudo-arcs and semi-conjugacies to interval maps

    OpenAIRE

    Boronski, Jan P.; Smith, Michel

    2017-01-01

    In 1985 M. Smith constructed a nonmetric pseudo-arc; i.e. a Hausdorff homogeneous, hereditary equivalent and hereditary indecomposable continuum. Taking advantage of a decomposition theorem of W. Lewis, he obtained it as a long inverse limit of metric pseudo-arcs with monotone bonding maps. Extending his approach, and the results of Lewis on lifting homeomorphisms, we construct a nonmetric pseudo-circle, and new examples of homogeneous 1-dimensional continua; e.g. a circle and solenoids of no...

  6. Determination of Sodium, Potassium, Magnesium, and Calcium Minerals Level in Fresh and Boiled Broccoli and Cauliflower by Atomic Absorption Spectrometry

    Science.gov (United States)

    Nerdy

    2018-01-01

    Vegetables from the cabbage family vegetables consumed by many people, which is known healthful, by eaten raw, boiled, or cooked (stir fry or soup). Vegetables like broccoli and cauliflower contain vitamins, minerals, and fiber. This study aims to determine the decrease percentage of sodium, potassium, magnesium, and calcium minerals level caused by boiled broccoli and cauliflower by atomic absorption spectrometry. Boiled broccoli and cauliflower prepared by given boiled treatment in boiling water for 3 minutes. Fresh and boiled broccoli and cauliflower carried out dry destruction, followed by quantitative analysis of sodium, potassium, magnesium, and calcium minerals respectively at a wavelength of 589.0 nm; 766.5 nm; 285.2 nm; and 422.7 nm, using atomic absorption spectrometry methods. After the determination of the sodium, potassium, magnesium, and calcium minerals level followed by validation of analytical methods with accuracy, precision, linearity, range, limit of detection (LOD), and limit of quantitation (LOQ) parameters. Research results show a decrease in the sodium, potassium, magnesium, and calcium minerals level in boiled broccoli and cauliflower compared with fresh broccoli and cauliflower. Validation of analytical methods gives results that spectrometry methods used for determining sodium, potassium, magnesium, and calcium minerals level are valid. It concluded that the boiled gives the effect of decreasing the minerals level significantly in broccoli and cauliflower.

  7. Molecular identification and thermoresistance to boiling of Nocardia farcinica and Nocardia cyriacigeorgica from bovine bulk tank milk

    OpenAIRE

    Condas, L.a.z [UNESP; Ribeiro, M.G.; T. Gonoi; Matsuzawa, T.; Yazawa, K.; Motta,R.G.; Franco,M.M.J.; Listoni,F.J.P.

    2012-01-01

    Two strains of Nocardia spp. were isolated from bovine milk of two individual bulk tank. Molecular identification classified the strains as Nocardia farcinica and Nocardia cyriacigeorgica. The thermorresistance to boiling of the isolates was carried out and was observed bacterial growth after boiling. Our findings indicate the potential risk of pathogen transmission to humans through contaminated milk with Nocardia spp.

  8. Data on the effect of boiling on the organosulfides and the hydrogen sulfide-releasing activity of garlic

    NARCIS (Netherlands)

    Tocmo, Restituto; Wu, Yuchen; Liang, Dong; Fogliano, Vincenzo; Huang, Dejian

    2017-01-01

    This article contains experimental data on the identification and quantification of the organosulfides on boiled garlic extracts. Data included are related to the research article “Boiling enriches the linear polysulfides and the hydrogen sulfide-releasing activity of garlic” (R. Tocmo, Y. Wu, D.

  9. Molecular identification and thermoresistance to boiling of Nocardia farcinica and Nocardia cyriacigeorgica from bovine bulk tank milk

    Directory of Open Access Journals (Sweden)

    L.A.Z. Condas

    2012-09-01

    Full Text Available Two strains of Nocardia spp. were isolated from bovine milk of two individual bulk tank. Molecular identification classified the strains as Nocardia farcinica and Nocardia cyriacigeorgica. The thermorresistance to boiling of the isolates was carried out and was observed bacterial growth after boiling. Our findings indicate the potential risk of pathogen transmission to humans through contaminated milk with Nocardia spp.

  10. Pseudo-arthrosis repair of a posterior cruciate ligament avulsion fracture

    OpenAIRE

    Hoogervorst, Paul; Gardeniers, J.W.M.; Moret-Wever, S.; Kampen, A. van

    2010-01-01

    A pseudo-arthrosis repair of a 4-year-old bony avulsion fracture of the PCL using a minimally invasive technique, screw fixation, and bone grafting is reported. The case presented seems to be rather unique due to the fragment size and the approach for pseudo-arthrosis repair. There was a good functional result following minimally invasive pseudo-arthrosis repair of a posterior cruciate ligament avulsion fracture. There are no previous reports of similar pseudo-arthrosis repairs, and other aut...

  11. Um caso de pseudo-hermafrodita masculino em um suíno

    OpenAIRE

    Corcini, Carine Dahl; Leon, Priscila Marques Moura de; Rambo, Gissele; Santos, Elisa Caroline da Silva; Varela Júnior, Antonio Sergio; Moreira, Fabiana; Fernandes, Cristina Gevehr; Lucia Júnior, Thomaz

    2009-01-01

    Os termos pseudo-hermafrodita e intersexo são utilizados para se referir a animais com traços sexuais ambíguos. O diagnostico de pseudo-hermafrodita é baseado nos vestígios de gônadas e aspecto fenotípico do trato reprodutivo. Os pseudo-hermafroditas masculinos são aqueles que possuem somente testículo. Este trabalho relata um caso de pseudo-hermafrodita masculino em um suíno, cujo aparelho reprodutor foi colhido na linha de abate de um frigorífico. O animal, com idade de 150 dias...

  12. Um caso de pseudo-hermafrodita masculino em um suíno

    OpenAIRE

    Corcini, Carine Dahl; Leon, Priscila Marques Moura; Rambo, Gissele; Santos, Elisa Caroline da Silva; Varela Junior, Antonio Sergio; Moreira, Fabiana; Fernandes, Cristina Gevehr; Lucia Junior, Thomaz

    2009-01-01

    Os termos pseudo-hermafrodita e intersexo são utilizados para se referir a animais com traços sexuais ambíguos. O diagnostico de pseudo-hermafrodita é baseado nos vestígios de gônadas e aspecto fenotípico do trato reprodutivo. Os pseudo-hermafroditas masculinos são aqueles que possuem somente testículo. Este trabalho relata um caso de pseudo-hermafrodita masculino em um suíno, cujo aparelho reprodutor foi colhido na linha de abate de um frigorífico. O animal, com idade de 150 dias e peso apro...

  13. Introduction to fractional and pseudo-differential equations with singular symbols

    CERN Document Server

    Umarov, Sabir

    2015-01-01

    The book systematically presents the theories of pseudo-differential operators with symbols singular in dual variables, fractional order derivatives, distributed and variable order fractional derivatives, random walk approximants, and applications of these theories to various initial and multi-point boundary value problems for pseudo-differential equations. Fractional Fokker-Planck-Kolmogorov equations associated with a large class of stochastic processes are presented. A complex version of the theory of pseudo-differential operators with meromorphic symbols based on the recently introduced complex Fourier transform is developed and applied for initial and boundary value problems for systems of complex differential and pseudo-differential equations.

  14. Bubble-assisted film evaporation correlation for saline water at sub-atmospheric pressures in horizontal-tube evaporator

    KAUST Repository

    Shahzad, Muhammad Wakil

    2013-01-01

    In falling film evaporators, the overall heat transfer coefficient is controlled by film thickness, velocity, liquid properties and the temperature differential across the film layer. This article presents the heat transfer behavior for evaporative film boiling on horizontal tubes, but working at low pressures of 0.93-3.60 kPa (corresponding solution saturation temperatures of 279-300 K) as well as seawater salinity of 15,000 to 90,000 mg/l or ppm. Owing to a dearth of literature on film-boiling at these conditions, the article is motivated by the importance of evaporative film boiling in the desalination processes such as the multi-effect distillation (MED) or multi-stage flashing (MSF): It is observed that in addition to the above-mentioned parameters, evaporative heat transfer of seawater is affected by the emergence of micro-bubbles within the thin film layer, particularly when the liquid saturation temperatures drop below 298 K (3.1 kPa). Such micro bubbles are generated near to the tube wall surfaces and they enhanced the heat transfer by two or more folds when compared with the predictions of conventional evaporative film boiling. The appearance of micro-bubbles is attributed to the rapid increase in the specific volume of vapor, i.e., dv/dT, at low saturation temperature conditions. A new correlation is thus proposed in this article and it shows good agreement to the measured data with an experimental uncertainty of 8% and regression RMSE of 3.5%. © 2012 Elsevier Ltd. All rights reserved.

  15. Fully Digital Chaotic Oscillators Applied to Pseudo Random Number Generation

    KAUST Repository

    Mansingka, Abhinav S.

    2012-05-01

    adapted for pseudo random number generation by truncating statistically defective bits. Finally, a novel post-processing technique using the Fibonacci series is proposed and implemented with a non-autonomous driven hyperchaotic system to provide pseudo random number generators with high nonlinear complexity and controllable period length that enables full utilization of all branches of the chaotic output as statistically secure pseudo random output.

  16. Agricultural aircraft and thermal imaging - from detecting sand boils at the levee to irrigation management

    Science.gov (United States)

    Thermal imaging has many potential uses from aerial platforms. A thermal imaging camera was brought into service to detect potential leakage and sand boils at the Mississippi River levee during the flood period of April and May, 2011. This camera was mounted on an agricultural aircraft and operated ...

  17. Effects of Hull Scratching, Soaking, and Boiling on Antinutrients in Japanese Red Sword Bean (Canavalia gladiata).

    Science.gov (United States)

    Une, Satsuki; Nonaka, Koji; Akiyama, Junich

    2016-10-01

    The effects of hull processing, soaking, and boiling on the content or activity of antinutrients in the red sword bean (RSB; Canavalia gladiata) were investigated. RSB seeds were compared with kidney bean (KB; Phaseolus vulgaris) seeds that are starch based and often used as processed products in Japan. RSB seeds had higher weight, thicker hull, and higher protein content, but lower moisture content compared with KB seeds. Because of the strong and thick hull, the relative water absorption of untreated RSB seeds was very low after soaking. Seeds were soaked after dehulling, scratching, and roasting. The results showed that hull scratching was the optimal method for increasing water absorption during soaking compared with dehulling and roasting. After soaking, the water used for soaking was discarded, since it had a high content of polyphenols and bitter taste, and RSB seeds were boiled in fresh water for 20, 40, and 60 min. The results showed that polyphenol and tannin contents, antioxidant activity, and hemagglutinating activity, as well as maltase, sucrase, and trypsin inhibitor activities in scratched RSB seeds decreased significantly after boiling compared with those in raw seeds, whereas amylase inhibitor activity showed no significant change. Overall, it was concluded that the combination of hull scratching, soaking, and boiling in fresh water can reduce thermal-stable or sensitive antinutrients in RSB and thus, significantly improve its nutritional value. © 2016 Institute of Food Technologists®.

  18. Bubble Departure from Metal-Graphite Composite Surfaces and Its Effects on Pool Boiling Heat Transfer

    Science.gov (United States)

    Chao, David F.; Sankovic, John M.; Motil, Brian J.; Yang, W-J.; Zhang, Nengli

    2010-01-01

    The formation and growth processes of a bubble in the vicinity of graphite micro-fiber tips on metal-graphite composite boiling surfaces and their effects on boiling behavior are investigated. It is discovered that a large number of micro bubbles are formed first at the micro scratches and cavities on the metal matrix in pool boiling. By virtue of the non-wetting property of graphite, once the growing micro bubbles touch the graphite tips, the micro bubbles are sucked by the tips and merged into larger micro bubbles sitting on the end of the tips. The micro bubbles grow rapidly and coalesce to form macro bubbles, each spanning several tips. The necking process of a detaching macro bubble is analyzed. It is revealed that a liquid jet is produced by sudden break-off of the bubble throat. The composite surfaces not only have higher temperatures in micro- and macrolayers but also make higher frequency of the bubble departure, which increase the average heat fluxes in both the bubble growth stage and in the bubble departure period. Based on these analyses, the enhancement mechanism of pool boiling heat transfer on composite surfaces is clearly revealed.

  19. Zero Boil-Off Methods for Large Scale Liquid Hydrogen Tanks Using Integrated Refrigeration and Storage

    Science.gov (United States)

    Notardonato, W. U.; Swanger, A. M.; Fesmire, J. E.; Jumper, K. M.; Johnson, W. L.; Tomsik, T. M.

    2017-01-01

    NASA has completed a series of tests at the Kennedy Space Center to demonstrate the capability of using integrated refrigeration and storage (IRAS) to remove energy from a liquid hydrogen (LH2) tank and control the state of the propellant. A primary test objective was the keeping and storing of the liquid in a zero boil-off state, so that the total heat leak entering the tank is removed by a cryogenic refrigerator with an internal heat exchanger. The LH2 is therefore stored and kept with zero losses for an indefinite period of time. The LH2 tank is a horizontal cylindrical geometry with a vacuum-jacketed, multi-layer insulation system and a capacity of 125,000 liters. The closed-loop helium refrigeration system was a Linde LR1620 capable of 390W cooling at 20K (without any liquid nitrogen pre-cooling). Three different control methods were used to obtain zero boil-off: temperature control of the helium refrigerant, refrigerator control using the tank pressure sensor, and duty cycling (on/off) of the refrigerator as needed. Summarized are the IRAS design approach, zero boil-off control methods, and results of the series of zero boil-off tests.

  20. MATHEMATICAL MODELING OF SELF-EXCITED VIBRATION OF PIPES CONTAINING MOBILE BOILING FLUID CLOTS

    Directory of Open Access Journals (Sweden)

    Yevgeniy Tolbatov

    2015-06-01

    Full Text Available Numerical modeling dynamic behavior of a pipe containing inner nonhomogeneous flows of a boiling fluid has been carried out. The system vibrations at different values of the parameters of the flow nonhomogeneity and its velocity are observed. The possibility of forming stable and unstable flows depending on the character ofnonhomogeneity and the velocity of fluid clots has been found.

  1. Impact of MR-guided boiling histotripsy in distinct murine tumor models

    NARCIS (Netherlands)

    Hoogenboom, Martijn; Eikelenboom, Dylan C.; van den Bijgaart, Renske J E; Heerschap, Arend; Wesseling, Pieter; den Brok, Martijn H; Fütterer, Jurgen J.; Adema, Gosse J

    2017-01-01

    Interest in mechanical high intensity focused ultrasound (HIFU) ablation is rapidly growing. Boiling histotripsy (BH) is applied for mechanical fragmentation of soft tissue into submicron fragments with limited temperature increase using the shock wave and cavitation effects of HIFU. Research on BH

  2. Boiling water scarification plus stratification improves germination of Iliamna rivularis (Malvaceae) seeds

    Science.gov (United States)

    Katri Himanen; Markku Nygren; R. Kasten Dumroese

    2012-01-01

    Scarification with boiling water plus stratification was most effective in improving germination of Iliamna rivularis (Douglas ex Hook.) Greene (Malvaceae) in an experiment that compared 3 treatments. Seeds from 15 sites representing 5 western US states were used in the experiment. Initial response of the seedlots to the treatments was similar, apart from one seedlot....

  3. Experimental study on pool boiling of distilled water and HFE7500 fluid under microgravity

    Science.gov (United States)

    Yang, Yan-jie; Chen, Xiao-qian; Huang, Yi-yong; Li, Guang-yu

    2018-02-01

    The experimental study on bubble behavior and heat transfer of pool boiling for distilled water and HFE7500 fluid under microgravity has been conducted by using drop tower in the National Microgravity Laboratory of China (NMLC). Two MCH ceramic plates of 20 mm(L) × 10 mm(W) × 1.2 mm(H) were used as the heaters. The nucleate boiling evolution under microgravity was observed during the experiment. It has been found that at the same heat flux, the bubbles of HFE7500 (which has smaller contact angle) grew faster and bigger, moved quickly on the heater surface, and were easier to merge into a central big bubble with other bubbles than that of distilled water. The whole process of bubbles coalescence from seven to one was recorded by using video camera. For distilled water (with bigger contact angle), the bubbles tended to keep at the nucleate location on heater surface, and the central big bubble evolved at its nucleate cite by absorbing smaller bubbles nearby. Compared with the bubbles under normal gravity, bubble radius of distilled water under microgravity was about 1.4 times bigger and of HFE7500 was about more than 6 times bigger till the end of experiment. At the beginning, pool boiling heat transfer of distilled water was advanced and then impeded under microgravity. As to HFE7500, the pool boiling impedes the heat transfer from heater to liquid under microgravity throughout the experiment.

  4. A Mini-channel Heat Exchanger System for Heating, Boiling, and Superheating Water by Radiant Combustion

    National Research Council Canada - National Science Library

    Sawyer, Mikel

    2004-01-01

    .... The channel hydraulic diameter was 0.14 Cm. The Reynolds number for the water ranged from 620 to 1,260 in the boiling section and from 1,260 to 3,140 in the superheating section, based on averaged fluid...

  5. How to subsidize contributions to public goods: Does the frog jump out of the boiling water?

    NARCIS (Netherlands)

    Offerman, T.; van der Veen, A.

    2009-01-01

    According to popular belief, frogs jump out of the water when the temperature is raised quickly while they are boiled to death when the water is gradually heated. In this paper, we investigate how humans respond to a very slow versus a very steep increase of a subsidy on contributions to a public

  6. Experimental and numerical stability investigations on natural circulation boiling water reactors

    NARCIS (Netherlands)

    Marcel, C.P.

    2007-01-01

    The stability of natural circulation boiling water reactors is investigated with a strong emphasis on experiments. Two different facilities are used for such a task: the GENESIS facility (to which a void reactivity feedback system is artificially added) and the CIRCUS facility. In addition,

  7. Allowable temperature rise in tubes of the piles: Precautions against boiling

    Energy Technology Data Exchange (ETDEWEB)

    Woods, W.K.

    1945-09-27

    In the design of the pile, it was considered advisable never to impose so great a heat load on any tube that the available header pressure would be insufficient to sweep the tube free of vapor if boiling should accidentally be initiated in the tube. Figures are given for the maximum temperature rises permissible, as function of header pressure and orifice diameter.

  8. Hard-Boiled for Hard Times in Leonardo Padura Fuentes's Detective Fiction

    Science.gov (United States)

    Song, H. Rosi

    2009-01-01

    Focusing on Leonardo Padura Fuentes's hard-boiled fiction, this essay traces the origin and evolution of the genre in Cuba. Padura Fuentes has challenged the officially sanctioned socialist "literatura policial" that became popular in the 1970s and 1980s. creating a new model of criticism that is not afraid to confront the island's socio-economic…

  9. A Review of Boiling Heat Transfer Processes at High Heat Flux

    Science.gov (United States)

    1991-04-01

    Bjorge , et al. (Ref. 168) and Stephan and Auracher (Ref. 169) later presented variations of the superposition approach. For additional approaches... Bjorge , R. W., Hall, G. R., and Rohsenow, W. M., "Correlation of Forced Convection Boiling Heat Transfer Data," Int. J. Heat Mass Trans., Vol. 25, No

  10. Correlation between Flow Pattern and Refrigerant Flow Boiling Heat Transfer in Microchannel Heat Sinks

    Science.gov (United States)

    Kuznetsov, V. V.; Kozulin, I. A.; Shamirzaev, A. S.

    2012-11-01

    Flow boiling in microchannel heat sinks is significantly influenced by capillary forces and by boundary constrains affecting the flow pattern and the heat transfer. In the present work, some characteristics of flow boiling heat transfer are explained using measurements of statistical parameters of gas-liquid two-phase flow in a rectangular microchannel. Such statistical characteristics of the flow as length distributions of elongated bubbles and liquid plugs, and also velocity distribution of the elongated bubbles are determined by dual laser scanning of the horizontal adiabatic nitrogen-water flow in a microchannel with the cross-section of 370×217 μm. Pressure gradients in gas-liquid flow are measured, and the results found well matching the predictions that account for capillary pressure on the gas-liquid interface. Heat transfer coefficients are measured for a horizontal copper microchannel heat sink with refrigerant R-21 as the working fluid. The heat sink contains 21 channels with cross section dimensions 930×335-μm. Distribution of local heat transfer coefficients along the length and the width of the microchannel plate is measured in the range of heat fluxes from 14 to 63 kW/m2; vapour quality was varied within 0.05-0.8, and pressure was about 1.6 bar. For flow boiling of R-21 refrigerant, contributions of nucleate boiling and forced convection are comparable. This allows us to examine the heat transfer mechanism for these complex conditions.

  11. Freon R141b flow boiling in silicon microchannel heat sinks: experimental investigation

    Science.gov (United States)

    Dong, Tao; Yang, Zhaochu; Bi, Qincheng; Zhang, Yulong

    2008-01-01

    This paper presents experimental investigations on Freon R141b flow boiling in rectangular microchannel heat sinks. The main aim is to provide an appropriate working fluid for microchannel flow boiling to meet the cooling demand of high power electronic devices. The microchannel heat sink used in this work contains 50 parallel channels, with a 60 × 200 ( W × H) μm cross-section. The flow boiling heat transfer experiments are performed with R141b over mass velocities ranging from 400 to 980 kg/(m2 s) and heat flux from 40 to 700 kW/m2, and the outlet pressure satisfying the atmospheric condition. The fluid flow-rate, fluid inlet/outlet temperature, wall temperature, and pressure drop are measured. The results indicate that the mean heat transfer coefficient of R141b flow boiling in present microchannel heat sinks depends heavily on mass velocity and heat flux and can be predicted by Kandlikar’s correlation (Heat Transf Eng 25(3):86 93, 2004). The two-phase pressure drop keeps increasing as mass velocity and exit vapor quality rise.

  12. Development of a par-boiled rice solar dryer | Abubakar | Bayero ...

    African Journals Online (AJOL)

    Energy is required in various forms to do useful work and necessary for the continual improvement in the standard of any society. This study presents the development of a par-boiled batch type rice solar dryer using an indirect mode natural convection solar energy. The dryer was designed and constructed to provide easier, ...

  13. The effects of fermentation and boiling on the level of hydrogen ...

    African Journals Online (AJOL)

    The effects of fermentation and boiling on the level of hydrogen cyanide in Mucuna pruriens (velvet bean) were investigated. Qualitative phytochemical analysis of Mucuna pruriens revealed the presence that tannins, saponins, cardiac glycosides and cyanogenic glycosides. Quantitative analysis revealed that raw Mucuna ...

  14. Magnetic resonance imaging of boiling induced by high intensity focused ultrasound

    Science.gov (United States)

    Khokhlova, Tatiana D.; Canney, Michael S.; Lee, Donghoon; Marro, Kenneth I.; Crum, Lawrence A.; Khokhlova, Vera A.; Bailey, Michael R.

    2009-01-01

    Both mechanically induced acoustic cavitation and thermally induced boiling can occur during high intensity focused ultrasound (HIFU) medical therapy. The goal was to monitor the temperature as boiling was approached using magnetic resonance imaging (MRI). Tissue phantoms were heated for 20 s in a 4.7-T magnet using a 2-MHz HIFU source with an aperture and radius of curvature of 44 mm. The peak focal pressure was 27.5 MPa with corresponding beam width of 0.5 mm. The temperature measured in a single MRI voxel by water proton resonance frequency shift attained a maximum value of only 73 °C after 7 s of continuous HIFU exposure when boiling started. Boiling was detected by visual observation, by appearance on the MR images, and by a marked change in the HIFU source power. Nonlinear modeling of the acoustic field combined with a heat transfer equation predicted 100 °C after 7 s of exposure. Averaging of the calculated temperature field over the volume of the MRI voxel (0.3×0.5×2 mm3) yielded a maximum of 73 °C that agreed with the MR thermometry measurement. These results have implications for the use of MRI-determined temperature values to guide treatments with clinical HIFU systems. PMID:19354416

  15. Methodology for Assessing a Boiling Liquid Expanding Vapor Explosion (BLEVE) Blast Potential

    Science.gov (United States)

    Keddy, Chris P.

    2012-01-01

    Composite Vessels are now used to store a variety of fluids or gases including cryogenic fluids under pressure. Sudden failure of these vessels under certain conditions can lead to a potentially catastrophic vapor expansion if thermal control is not maintained prior to failure. This can lead to a "Boiling Liquid Expanding Vapor Explosion" or BLEVE.

  16. A sensitivity analysis of the mass balance equation terms in subcooled flow boiling

    Energy Technology Data Exchange (ETDEWEB)

    Braz Filho, Francisco A.; Caldeira, Alexandre D.; Borges, Eduardo M., E-mail: fbraz@ieav.cta.br, E-mail: alexdc@ieav.cta.br, E-mail: eduardo@ieav.cta.br [Instituto de Estudos Avancados (IEAv), Sao Jose dos Campos, SP (Brazil). Div. de Energia Nuclear

    2013-07-01

    In a heated vertical channel, the subcooled flow boiling occurs when the fluid temperature reaches the saturation point, actually a small overheating, near the channel wall while the bulk fluid temperature is below this point. In this case, vapor bubbles are generated along the channel resulting in a significant increase in the heat flux between the wall and the fluid. This study is particularly important to the thermal-hydraulics analysis of Pressurized Water Reactors (PWRs). The computational fluid dynamics software FLUENT uses the Eulerian multiphase model to analyze the subcooled flow boiling. In a previous paper, the comparison of the FLUENT results with experimental data for the void fraction presented a good agreement, both at the beginning of boiling as in nucleate boiling at the end of the channel. In the region between these two points the comparison with experimental data was not so good. Thus, a sensitivity analysis of the mass balance equation terms, steam production and condensation, was performed. Factors applied to the terms mentioned above can improve the agreement of the FLUENT results to the experimental data. Void fraction calculations show satisfactory results in relation to the experimental data in pressures values of 15, 30 and 45 bars. (author)

  17. Suitability of the boiling method of DNA extraction in mosquitoes for routine molecular analyses

    Directory of Open Access Journals (Sweden)

    D. K. Sarma

    2014-09-01

    Full Text Available This communication deals with the experience on suitability of the boiling method of DNA extraction from mosquito tissues. The DNA extracted by this method was found, by and large, stable after 30 months of storage. The method is useful for routine molecular entomological applications.

  18. 75 FR 7632 - Advisory Committee on Reactor Safeguards (ACRS) Meeting of the Subcommittee on Advanced Boiling...

    Science.gov (United States)

    2010-02-22

    ... COMMISSION Advisory Committee on Reactor Safeguards (ACRS) Meeting of the Subcommittee on Advanced Boiling Water Reactor (ABWR) The ACRS Subcommittee on ABWR will hold a meeting on March 2, 2010, at 11545...: February 12, 2010. Antonio F. Dias, Chief Reactor Safety Branch B, Advisory Committee on Reactor Safeguards...

  19. 75 FR 10840 - Advisory Committee on Reactor Safeguards (ACRS) Meeting of the Subcommittee on Advanced Boiling...

    Science.gov (United States)

    2010-03-09

    ... COMMISSION Advisory Committee on Reactor Safeguards (ACRS) Meeting of the Subcommittee on Advanced Boiling Water Reactor (ABWR); Notice of Meeting The ACRS Subcommittee on ABWR will hold a meeting on March 18... 3, 2010. Antonio F. Dias, Chief, Reactor Safety Branch B, Advisory Committee on Reactor Safeguards...

  20. Effect of Boiling and Frying on the Total Carbohydrate, Vitamin C ...

    African Journals Online (AJOL)

    The minerals evaluated are iron, zinc, magnesium, sodium, calcium and copper. These were determined by the atomic absorption spectrophotometric method. There was no significant difference (p > 0.05) in the total carbohydrate content of the boiled and fried sweet and Irish potatoes compared with their raw tubers.