Energy Technology Data Exchange (ETDEWEB)
Wilms, R Scott [Los Alamos National Laboratory; Carlson, Bryan [Los Alamos National Laboratory; Coons, James [Los Alamos National Laboratory; Kubic, William [Los Alamos National Laboratory
2008-01-01
This presentation describes the development of the proposed Process Flow Diagram (PFD) for the Tokamak Exhaust Processing System (TEP) of ITER. A brief review of design efforts leading up to the PFD is followed by a description of the hydrogen-like, air-like, and waterlike processes. Two new design values are described; the mostcommon and most-demanding design values. The proposed PFD is shown to meet specifications under the most-common and mostdemanding design values.
Modeling process flow using diagrams
Kemper, B.; de Mast, J.; Mandjes, M.
2010-01-01
In the practice of process improvement, tools such as the flowchart, the value-stream map (VSM), and a variety of ad hoc variants of such diagrams are commonly used. The purpose of this paper is to present a clear, precise, and consistent framework for the use of such flow diagrams in process
Modeling process flow using diagrams
Kemper, B.; de Mast, J.; Mandjes, M.
2010-01-01
In the practice of process improvement, tools such as the flowchart, the value-stream map (VSM), and a variety of ad hoc variants of such diagrams are commonly used. The purpose of this paper is to present a clear, precise, and consistent framework for the use of such flow diagrams in process improv
Process Flow Diagrams for Training and Operations
Venter, Jacobus
This paper focuses on the use of process flow diagrams for training first responders who execute search and seizure warrants at electronic crime scenes. A generic process flow framework is presented, and the design goals and layout characteristics of process flow diagrams are discussed. An evaluation of the process flow diagrams used in training courses indicates that they are beneficial to first responders performing searches and seizures, and they speed up investigations, including those conducted by experienced personnel.
Functionality Semantics of Predicate Data Flow Diagram
Institute of Scientific and Technical Information of China (English)
高晓雷; 缪淮扣; 刘玲
2004-01-01
SOZL (structured methodology + object-oriented methodology + Z language) is a language that attempts to integrate structured method, object-oriented method and formal method. The core of this language is predicate data flow diagram (PDFD). In order to eliminate the ambiguity of predicate data flow diagrams and their associated textual specifications, a formalization of the syntax and semantics of predicate data flow diagrams is necessary. In this paper we use Z notation to define an abstract syntax and the related structural constraints for the PDFD notation, and provide it with an axiomatic semantics based on the concept of data availability and functionality of predicate operation. Finally, an example is given to establish functionality consistent decomposition on hierarchical PDFD (HPDFD).
Disconnected diagrams with twisted-mass fermions
Abdel-Rehim, Abdou; Constantinou, Martha; Finkenrath, Jacob; Hadjiyiannakou, Kyriakos; Jansen, Karl; Kallidonis, Christos; Koutsou, Giannis; Avilés-Casco, Alejandro Vaquero
2016-01-01
The latest results from the Twisted-Mass collaboration on disconnected diagrams at the physical value of the pion mass are presented. In particular, we focus on the sigma terms, the axial charges and the momentum fraction, all of them for the nucleon. A detailed error analysis for each observable follows, showing the strengths and weaknesses of the one-end trick. Alternatives are discussed.
Phase diagram of twisted mass lattice QCD
Sharpe, Stephen R.; Wu, Jackson M.
2004-11-01
We use the effective chiral Lagrangian to analyze the phase diagram of two-flavor twisted mass lattice QCD as a function of the normal and twisted masses, generalizing previous work for the untwisted theory. We first determine the chiral Lagrangian including discretization effects up to next-to-leading order (NLO) in a combined expansion in which m2π/(4πfπ)2˜aΛ (a being the lattice spacing, and Λ=ΛQCD). We then focus on the region where m2π/(4πfπ)2˜(aΛ)2, in which case competition between leading and NLO terms can lead to phase transitions. As for untwisted Wilson fermions, we find two possible phase diagrams, depending on the sign of a coefficient in the chiral Lagrangian. For one sign, there is an Aoki phase for pure Wilson fermions, with flavor and parity broken, but this is washed out into a crossover if the twisted mass is nonvanishing. For the other sign, there is a first order transition for pure Wilson fermions, and we find that this transition extends into the twisted mass plane, ending with two symmetrical second order points at which the mass of the neutral pion vanishes. We provide graphs of the condensate and pion masses for both scenarios, and note a simple mathematical relation between them. These results may be of importance to numerical simulations.
STRUKTURISASI ENTITY RELATIONSHIP DIAGRAM DAN DATA FLOW DIAGRAM BERBASIS BUSINESS EVENT-DRIVEN
Suroto Adi; Desi Maya Kristin
2014-01-01
Entity relationship diagram (ERD) and data flow diagram (DFD) modeling are necessary parts in analysis and design of structured information systems in business. Definition of entities in the ERD, the process, and datastore in the DFD have well described in a lot of literatures. However, practically it is not easy to explain how to design ERD and DFD models so that the students well understand the modeling steps, especially in business applications. This study discussed step-by-step systematic...
Introducing the Circular Flow Diagram to Business Students
Daraban, Bogdan
2010-01-01
The circular flow of income diagram is a simplified representation of the functioning of a free-market economic system. It illustrates how businesses interact with the other economic participants within the key macroeconomic markets that coordinate the flow of income through the national economy. Therefore, it can provide students of business with…
The fundamental diagram : a macroscopic traffic flow model.
Botma, H.
1976-01-01
In models of traffic flow, the interactions between vehicles are of prime interest, and are based on characteristics of the drivers, road and vehicles. The fundamental diagram is a representation of a relationship on a macroscopic level in the steady state between the quantity of traffic and a chara
Software Tool Integrating Data Flow Diagrams and Petri Nets
Thronesbery, Carroll; Tavana, Madjid
2010-01-01
Data Flow Diagram - Petri Net (DFPN) is a software tool for analyzing other software to be developed. The full name of this program reflects its design, which combines the benefit of data-flow diagrams (which are typically favored by software analysts) with the power and precision of Petri-net models, without requiring specialized Petri-net training. (A Petri net is a particular type of directed graph, a description of which would exceed the scope of this article.) DFPN assists a software analyst in drawing and specifying a data-flow diagram, then translates the diagram into a Petri net, then enables graphical tracing of execution paths through the Petri net for verification, by the end user, of the properties of the software to be developed. In comparison with prior means of verifying the properties of software to be developed, DFPN makes verification by the end user more nearly certain, thereby making it easier to identify and correct misconceptions earlier in the development process, when correction is less expensive. After the verification by the end user, DFPN generates a printable system specification in the form of descriptions of processes and data.
Mass loss rates in the Hertzsprung-Russell diagram
Energy Technology Data Exchange (ETDEWEB)
Jager, C. de; Nieuwenhuijzen, H.; Hucht, K.A. van der
1988-02-01
From the literature we collected values for the rate of mass loss for 271 stars, nearly all of population I, and of spectral types 0 through M. Rates of stellar mass loss determined according to six different methods were compared and appear to yield the same result per star within the limits of errors; this is true regardless of the star's position in the HR-diagram. Thus average rates of mass loss were determined, and weights were allocated to the M-determinations for each star. In addition we studied some groups of other stars: fast rotators (22 Be-type stars), and chemically evolved stars (31 Wolf-Rayet stars; 11 C- and 4 S-type stars and 15 nuclei of planetary nebulae). The chemically evolved stars have rates of mass loss which are larger than those of ''normal'' stars occupying the same positions in the Hertzprung-Russel diagram, by factors: 160 for Wolf-Rayet stars; 11 for C-type stars, and by estimated factors of 10/sup 3/ to 10/sup 4/ for the nuclei of planetary nebulae.
The phase diagram of twisted mass lattice QCD
Sharpe, S R; Sharpe, Stephen R.; Wu, Jackson M. S.
2004-01-01
We use the effective chiral Lagrangian to analyze the phase diagram of two-flavor twisted mass lattice QCD as a function of the normal and twisted masses, generalizing previous work for the untwisted theory. We first determine the chiral Lagrangian including discretization effects up to next-to-leading order (NLO) in a combined expansion in which m_\\pi^2/(4\\pi f_\\pi)^2 ~ a \\Lambda (a being the lattice spacing, and \\Lambda = \\Lambda_{QCD}). We then focus on the region where m_\\pi^2/(4\\pi f_\\pi)^2 ~ (a \\Lambda)^2, in which case competition between leading and NLO terms can lead to phase transitions. As for untwisted Wilson fermions, we find two possible phase diagrams, depending on the sign of a coefficient in the chiral Lagrangian. For one sign, there is an Aoki phase for pure Wilson fermions, with flavor and parity broken, but this is washed out into a crossover if the twisted mass is non-vanishing. For the other sign, there is a first order transition for pure Wilson fermions, and we find that this transitio...
Numerical Computation of Two-loop Box Diagrams with Masses
Yuasa, F; Hamaguchi, N; Ishikawa, T; Kato, K; Kurihara, Y; Fujimoto, J; Shimizu, Y
2011-01-01
A new approach is presented to evaluate multi-loop integrals, which appear in the calculation of cross-sections in high-energy physics. It relies on a fully numerical method and is applicable to a wide class of integrals with various mass configurations. As an example, the computation of two-loop planar and non-planar box diagrams is shown. The results are confirmed by comparisons with other techniques, including the reduction method, and by a consistency check using the dispersion relation.
Ward-type Data Flow Diagram Simulating System
Arisawa, Makoto; Iwatani, Yasuaki; Kato, Juniji
1989-01-01
In the present paper we discuss about a Ward-type Data Flow Diagram Simulating System that we implemented. The system works on NEC PC9801/VX personal computer with a mouse. It consists of two parts, DFD editor and DFD Interpreter. The DFD Editor is to draw Ward-type DFD's along with Mini Spec. in the form of Finite State Automaton and Guarded Command. The DFD Interpreter is to simulate the parallel process interactions and to output the results. We have a simple assumption that time sequence ...
Effect of speed matching on fundamental diagram of pedestrian flow
Fu, Zhijian; Luo, Lin; Yang, Yue; Zhuang, Yifan; Zhang, Peitong; Yang, Lizhong; Yang, Hongtai; Ma, Jian; Zhu, Kongjin; Li, Yanlai
2016-09-01
Properties of pedestrian may change along their moving path, for example, as a result of fatigue or injury, which has never been properly investigated in the past research. The paper attempts to study the speed matching effect (a pedestrian adjusts his velocity constantly to the average velocity of his neighbors) and its influence on the density-velocity relationship (a pedestrian adjust his velocity to the surrounding density), known as the fundamental diagram of the pedestrian flow. By the means of the cellular automaton, the simulation results fit well with the empirical data, indicating the great advance of the discrete model for pedestrian dynamics. The results suggest that the system velocity and flow rate increase obviously under a big noise, i.e., a diverse composition of pedestrian crowd, especially in the region of middle or high density. Because of the temporary effect, the speed matching has little influence on the fundamental diagram. Along the entire density, the relationship between the step length and the average pedestrian velocity is a piecewise function combined two linear functions. The number of conflicts reaches the maximum with the pedestrian density of 2.5 m-2, while decreases by 5.1% with the speed matching.
Stock flow diagram analysis on solid waste management in Malaysia
Zulkipli, Faridah; Nopiah, Zulkifli Mohd; Basri, Noor Ezlin Ahmad; Kie, Cheng Jack
2016-10-01
The effectiveness on solid waste management is a major importance to societies. Numerous generation of solid waste from our daily activities has risked for our communities. These due to rapid population grow and advance in economic development. Moreover, the complexity of solid waste management is inherently involved large scale, diverse and element of uncertainties that must assist stakeholders with deviating objectives. In this paper, we proposed a system dynamics simulation by developing a stock flow diagram to illustrate the solid waste generation process and waste recycle process. The analysis highlights the impact on increasing the number of population toward the amount of solid waste generated and the amount of recycled waste. The results show an increment in the number of population as well as the amount of recycled waste will decrease the amount of waste generated. It is positively represent the achievement of government aim to minimize the amount of waste to be disposed by year 2020.
Phase diagrams properties of the mixed traffic flow on a crossroad
Li, Qi-Lang; Wang, Bing-Hong; Liu, Mu-Ren
2010-11-01
Based on the Ishibashi and Fukui crossroad traffic flow model [Y. Ishibashi and M. Fukui. J. Phys. Soc. Japan. 70 (2001) 2793], mixed traffic flow (i.e., the fast and slow vehicles with different maximum velocities are mixed) is investigated in this work. According to the numerical simulation results and the principle for constructing the phase diagram, phase diagrams for mixed traffic flow are constructed. It is noted that the topology of these phase diagrams is similar to that of phase diagrams for homogeneous vehicles (which refers to slow vehicles only). From the phase diagrams, it is evident that mixed traffic flow is influenced by the mixing rate f (fraction of slow and fast vehicles) in regions II and V, but not in other regions. Although a mixture of fast and slow vehicles is introduced in the crossroad traffic flow model, the separation between phases in the phase diagrams remains linear. For a given q (the vehicle density on the northbound road), one flow plateau appears in regions IIx or IVy, while two maximum flow plateaus appear in region V in each of the phase diagrams. The maximum flow values in region V reflect the maximum traffic capacity for the traffic system as defined in this work. Since mixed traffic flow is a common phenomenon in real traffic, this work may offer help in real traffic simulations and traffic management.
Phase Diagram of Wilson and Twisted Mass Fermions at finite isospin chemical potential
Kieburg, M; Verbaarschot, J J M; Zafeiropoulos, S
2014-01-01
Wilson Fermions with untwisted and twisted mass are widely used in lattice simulations. Therefore one important question is whether the twist angle and the lattice spacing affect the phase diagram. We briefly report on the study of the phase diagram of QCD in the parameter space of the degenerate quark masses, isospin chemical potential, lattice spacing, and twist angle by employing chiral perturbation theory. Moreover we calculate the pion masses and their dependence on these four parameters.
Topologically distinct Feynman diagrams for mass operator in electron-phonon interaction
Directory of Open Access Journals (Sweden)
C.C. Tovstyuk
2009-01-01
Full Text Available The new method for designing topologically distinct Feynman diagrams for electron's mass operator in electron-phonon interaction is developed using the permutation group theory. The carried out classification of DPs allows to choose the classes, corresponding to disconnected diagrams, to singly connected diagrams, direct ("tadpole" diagrams, to diagrams corresponding to phonon Green functions. After this classification the set of considered double permutations is reduced to one class since only these are relevant to mass operator. We derive analytical expressions which allow to identify the DP, and to choose the phonon components, which are not accepted in every type. To avoid repetition of asymmetric diagrams, which correspond to the same analytical expression, we introduce the procedure of inversion in phonon component, and identify symmetric as well as a pair of asymmetric phonon components. For every type of DP (denoted by its digital encoding, taking into account its symmetry, we perform a set of transformations on this DP, list all DPs of the type and all the corresponding Feynman diagrams of mass operator automatically. It is clear that no more expressions (diagrams for the relevant order of perturbation theory for mass operator can be designed.
National Research Council Canada - National Science Library
Hiroshi OAKI; Masaru ISHIDA; Tsuneo IKAWA
1981-01-01
A new diagram called structured process energy-exergy-flow diagram (SPEED) is proposed to systematically analyze the structure of energy flow in chemical processes and to design the process structures effectively...
Neutral mesons and disconnected diagrams in Twisted Mass QCD
Michael, C
2007-01-01
We evaluate properties of neutral mesons in Nf=2 dynamical simulations of TMQCD at maximal twist. The pion is explored - establishing the size of the isospin splitting (an order a^2 effect). We investigate the eta' (the Nf=2 flavour singlet pseudoscalar meson) and neutral rho and scalar mesons. We show that disconnected diagrams can be evaluated very efficiently in TMQCD using variance reduction methods.
Making Data Flow Diagrams Accessible for Visually Impaired Students Using Excel Tables
Sauter, Vicki L.
2015-01-01
This paper addresses the use of Excel tables to convey information to blind students that would otherwise be presented using graphical tools, such as Data Flow Diagrams. These tables can supplement diagrams in the classroom when introducing their use to understand the scope of a system and its main sub-processes, on exams when answering questions…
Quantifying the implicit process flow abstraction in SBGN-PD diagrams with Bio-PEPA
National Research Council Canada - National Science Library
Loewe, Laurence; Moodie, Stuart; Hillston, Jane
2009-01-01
.... Its qualitative Process Diagrams (SBGN-PD) are based on an implicit Process Flow Abstraction (PFA) that can also be used to construct quantitative representations, which can be used for automated analyses of the system...
Pulsating laminar pipe flows with sinusoidal mass flux variations
Ünsal, B.; Ray, S.; Durst, F.; Ertunç, Ö.
2005-11-01
Combined analytical and experimental investigation of sinusoidal mass flow-controlled, pulsating, laminar and fully developed pipe flow was carried out. The experimental investigation employed a mass flow control unit built at LSTM-Erlangen for the present investigation. For the analytical investigation, the equations describing such flows were normalized to allow for a general solution, depending only on the normalized amplitude mA* of the mass flow pulsation and the normalized frequency F. The analytical and experimental results are presented in this normalized way and it is shown that good agreement between the results of the authors is obtained. A diagram is presented for the condition of flow reversal in terms of the dimensionless frequency F and the mass flow rate amplitude mA*.
Fluctuation diagrams for hot-wire anemometry in subsonic compressible flows
Stainback, P. C.; Nagabushana, K. A.
1991-01-01
The concept of using 'fluctuation diagrams' for describing basic fluctuations in compressible flows was reported by Kovasznay in the 1950's. The application of this technique, for the most part, was restricted to supersonic flows. Recently, Zinovev and Lebiga published reports where they considered the fluctuation diagrams in subsonic compressible flows. For the above studies, the velocity and density sensitivities of the heated wires were equal. However, there are considerable data, much taken in the 1950's, which indicate that under some conditions the velocity and density sensitivities are not equal in subsonic compressible flows. Therefore, possible fluctuation diagrams are described for the cases where the velocity and density sensitivities are equal and the more general cases where they are unequal.
The non-equilibrium phase diagrams of flow-induced crystallization and melting of polyethylene.
Wang, Zhen; Ju, Jianzhu; Yang, Junsheng; Ma, Zhe; Liu, Dong; Cui, Kunpeng; Yang, Haoran; Chang, Jiarui; Huang, Ningdong; Li, Liangbin
2016-09-09
Combining extensional rheology with in-situ synchrotron ultrafast x-ray scattering, we studied flow-induced phase behaviors of polyethylene (PE) in a wide temperature range up to 240 °C. Non-equilibrium phase diagrams of crystallization and melting under flow conditions are constructed in stress-temperature space, composing of melt, non-crystalline δ, hexagonal and orthorhombic phases. The non-crystalline δ phase is demonstrated to be either a metastable transient pre-order for crystallization or a thermodynamically stable phase. Based on the non-equilibrium phase diagrams, nearly all observations in flow-induced crystallization (FIC) of PE can be well understood. The interplay of thermodynamic stabilities and kinetic competitions of the four phases creates rich kinetic pathways for FIC and diverse final structures. The non-equilibrium flow phase diagrams provide a detailed roadmap for precisely processing of PE with designed structures and properties.
Fundamental diagram in traffic flow of mixed vehicles on multi-lane highway
Tanaka, Katsunori; Nagatani, Takashi; Masukura, Shuichi
2008-09-01
We study the fundamental diagram for traffic flow of vehicular mixture on a multi-lane highway. We present the car-following model of multi-lane traffic in which slow and fast vehicles flow with changing lanes. We investigate the traffic states of the vehicular mixture under the periodic boundary. Two values of the current appear at a density and two current curves are obtained. Vehicles move with changing lanes in the traffic state of high current, while vehicles move without changing lanes in the traffic state of low current. They depend on the density, the fraction of slow vehicles, and the initial condition. In the high-current curve, the jamming transition between the free flow and the jammed state occurs at a low density. The fundamental diagrams (current-density diagrams) are shown for the single-lane, two-lane, three-lane, and four-lane traffics.
Directory of Open Access Journals (Sweden)
Chuzlov Vjacheslav
2016-01-01
Full Text Available An approach to simulation of hydrocarbons refining processes catalytic reactors. The kinetic and thermodynamic research of light naphtha isomerization process was conducted. The kinetic parameters of hydrocarbon feedstock chemical conversion on different types of platinum-content catalysts was established. The estimation of efficiency of including different types of isomerization technologies in oil refinery flow diagram was performed.
Multivalued fundamental diagrams of traffic flow in the kinetic Fokker-Planck limit
Visconti, Giuseppe; Puppo, Gabriella; Tosin, Andrea
2016-01-01
Starting from interaction rules based on two levels of stochasticity we study the influence of the microscopic dynamics on the macroscopic properties of vehicular flow. In particular, we study the qualitative structure of the resulting flux-density and speed-density diagrams for different choices of the desired speeds. We are able to recover multivalued diagrams as a result of the existence of a one-parameter family of stationary distributions, whose expression is analytically found by means of a Fokker-Planck approximation of the initial Boltzmann-type model.
The Evolution of Advanced Merger (U)LIRGs on the Color-Stellar Mass Diagram
Guo, Rui; Xia, Xiao-Yang
2016-01-01
Based on a sample of 79 local advanced merger (adv-merger) (U)LIRGs, we search for the evidence of quenching process by investigating the distributions of the star formation history indicators (EW(H$\\alpha$), EW(H$\\delta$$_A$) and D$_n(4000)$) on the NUV-r color-mass and SFR-$M_{\\ast}$ diagrams. The distributions of the EW(H$\\alpha$) and D$_n(4000)$ on the NUV-r color-mass diagram show clear trends that at a given stellar mass, galaxies with redder NUV-r colors have smaller EW(H$\\alpha$) and larger D$_n(4000)$. The reddest adv-merger (U)LIRGs close to the green valley have D$_n(4000)$$>1.4$ mostly. In addition, in the SFR-$M_{\\ast}$ diagram, as the SFR decreases, the EW(H$\\alpha$) decreases and the D$_n(4000)$ increases, implying that the adv-merger (U)LIRGs on the star formation main sequence have more evolved stellar populations than those above the main sequence. These results indicate that a fraction of the adv-merger (U)LIRGs have already exhibited signs of fading from the starburst phase and that the NU...
Phase Diagram of Dynamical Twisted Mass Wilson Fermions at Finite Isospin Chemical Potential
Janssen, Oliver; Splittorff, K; Verbaarschot, Jacobus J M; Zafeiropoulos, Savvas
2015-01-01
We consider the phase diagram of twisted mass Wilson fermions of two-flavor QCD in the parameter space of the quark mass, the isospin chemical potential, the twist angle and the lattice spacing. This work extends earlier studies in the continuum and those at zero chemical potential. We evaluate the phase diagram as well as the spectrum of the (pseudo-)Goldstone bosons using the chiral Lagrangian for twisted mass Wilson fermions at non-zero isospin chemical potential. The phases are obtained from a mean field analysis. At zero twist angle we find that already an infinitesimal isospin chemical potential destroys the Aoki phase. The reason is that in this phase we have massless Goldstone bosons with a non-zero isospin charge. At finite twist angle only two different phases are present, one phase which is continuously connected to the Bose condensed phase at non-zero chemical potential and another phase which is continuously connected to the normal phase. For either zero or maximal twist the phase diagram is more...
Dark energy in six nearby galaxy flows: Synthetic phase diagrams and self-similarity
Chernin, A. D.; Teerikorpi, P.; Dolgachev, V. P.; Kanter, A. A.; Domozhilova, L. M.; Valtonen, M. J.; Byrd, G. G.
2012-09-01
Outward flows of galaxies are observed around groups of galaxies on spatial scales of about 1 Mpc, and around galaxy clusters on scales of 10 Mpc. Using recent data from the Hubble Space Telescope (HST), we have constructed two synthetic velocity-distance phase diagrams: one for four flows on galaxy-group scales and the other for two flows on cluster scales. It has been shown that, in both cases, the antigravity produced by the cosmic dark-energy background is stronger than the gravity produced by the matter in the outflow volume. The antigravity accelerates the flows and introduces a phase attractor that is common to all scales, corresponding to a linear velocity-distance relation (the local Hubble law). As a result, the bundle of outflow trajectories mostly follow the trajectory of the attractor. A comparison of the two diagrams reveals the universal self-similar nature of the outflows: their gross phase structure in dimensionless variables is essentially independent of their physical spatial scales, which differ by approximately a factor of 10 in the two diagrams.
On the effect of stochastic transition in the fundamental diagram of traffic flow
Siqueira, Adriano Francisco; Wu, Chen; Qian, Wei-Liang
2014-01-01
In this work, we propose an alternative stochastic model for the fundamental diagram of traffic flow with minimal number of parameters. Our approach is based on a mesoscopic viewpoint of the traffic system in terms of the dynamics of vehicle velocity transitions. A key feature of the present approach lies in its stochastic nature which makes it possible to describe not only the flow-concentration relation, the so-called fundamental diagram in traffic engineering, but also its variance -- an important ingredient in the observed data of traffic flow. It is shown that the model can be seen as a derivative of the Boltzmann equation when assuming a discrete velocity spectrum. The latter assumption significantly simplifies the mathematics and therefore, facilitates the study of its physical content through the analytic solutions. The model parameters are then adjusted to reproduce the observed traffic flow on the "23 de maio" highway in the Brazilian city of Sao Paulo, where both the fundamental diagram and its var...
Two-loop snail diagrams: relating neutrino masses to dark matter
Farzan, Yasaman
2014-01-01
Various mechanisms have been developed to explain the origin of Majorana neutrino masses. One of them is radiative mass generation. Two-loop mass generation is of particular interest because the masses and couplings of new particles propagating in the loop can be in the range testable by other experiments and observations. In order for the radiative mass suppression to be reliable, it should be guaranteed that lower loop contributions are suppressed. Based on loop topology and the form of electroweak presentation of the particles propagating in the loop, one can determine whether a lower---and therefore dominant---loop contribution is possible. We present a model based on these general considerations which leads to neutrino masses via a two-loop diagram which we dub as "snail-diagram". The model has two natural candidates for dark matter one of them being a neutral Dirac fermion which can satisfy the conditions of the thermal freeze-out scenario by annihilation to lepton pairs. We comment on the possibility o...
Perancangan Model Data Flow Diagram Untuk Mengukur Kualitas Website Menggunakan Webqual 4.0
Directory of Open Access Journals (Sweden)
Karina Hapsari
2017-05-01
Full Text Available The more competition the e-commerce company and the development of technology company in Indonesia, website of Zalora Indonesia traffic rank declining. Measuring the quality of website by using WebQual 4.0 will help manage the web to be able to adjust the quality of the web with user perception. The research aims to make design of Data Flow Diagram model to measure website quality using WebQual 4.0 based on user satisfaction variable. A case study was conducted on the Zalora Indonesia website. Data Flow model is used to make design of system model recommendation, while WebQual 4.0 method is used to measure website quality to user satisfaction. The research data using primary data in the form of questionnaires involving 384 respondents in the city of Bandung who had transacted on the website Zalora Indonesia. Data analysis technique applies descriptive analysis. Based on the research result on the quality of the website Zalora Indonesia, simultaneous positive and significant impact on user satisfaction Zalora Indonesia website. t test result showed that three variables partially have a posotive impact on user satisfaction Zalora Indonesia website is usability quality, information quality and service interaction quality, with Information quality variable has largest impact. Therefore, the modeling system using the Context Diagram-Data Flow Diagram focused on information quality variable.
On-line metabolic pathway analysis based on metabolic signal flow diagram.
Shi, H; Shimizu, K
In this work, an integrated modeling approach based on a metabolic signal flow diagram and cellular energetics was used to model the metabolic pathway analysis for the cultivation of yeast on glucose. This approach enables us to make a clear analysis of the flow direction of the carbon fluxes in the metabolic pathways as well as of the degree of activation of a particular pathway for the synthesis of biomaterials for cell growth. The analyses demonstrate that the main metabolic pathways of Saccharomyces cerevisiae change significantly during batch culture. Carbon flow direction is toward glycolysis to satisfy the increase of requirement for precursors and energy. The enzymatic activation of TCA cycle seems to always be at normal level, which may result in the overflow of ethanol due to its limited capacity. The advantage of this approach is that it adopts both virtues of the metabolic signal flow diagram and the simple network analysis method, focusing on the investigation of the flow directions of carbon fluxes and the degree of activation of a particular pathway or reaction loop. All of the variables used in the model equations were determined on-line; the information obtained from the calculated metabolic coefficients may result in a better understanding of cell physiology and help to evaluate the state of the cell culture process. Copyright 1998 John Wiley & Sons, Inc.
Towards an estimation of water masses formation areas from SMOS-based TS diagrams
Klockmann, Marlene; Sabia, Roberto; Fernandez-Prieto, Diego; Donlon, Craig; Font, Jordi
2014-05-01
Temperature-Salinity (TS) diagrams emphasize the mutual variability of ocean temperature and salinity values, relating them to the corresponding density. Canonically used in oceanography, they provide a means to characterize and trace ocean water masses. In [1], a first attempt to estimate surface-layer TS diagrams based on satellite measurements has been performed, profiting from the recent availability of spaceborne salinity data. In fact, the Soil Moisture and Ocean Salinity (SMOS, [2]) and the Aquarius/SAC-D [3] satellite missions allow to study the dynamical patterns of Sea Surface Salinity (SSS) for the first time on a global scale. In [4], given SMOS and Aquarius salinity estimates, and by also using Sea Surface Temperature (SST) from the Operational Sea Surface Temperature and Sea Ice Analysis (OSTIA, [5]) effort, experimental satellite-based TS diagrams have been routinely derived for the year 2011. They have been compared with those computed from ARGO-buoys interpolated fields, referring to a customised partition of the global ocean into seven regions, according to the water masses classification of [6]. In [7], moreover, besides using TS diagrams as a diagnostic tool to evaluate the temporal variation of SST and SSS (and their corresponding density) as estimated by satellite measurements, the emphasis was on the interpretation of the geographical deviations with respect to the ARGO baseline (aiming at distinguishing between the SSS retrieval errors and the additional information contained in the satellite data with respect to ARGO). In order to relate these mismatches to identifiable oceanographic structures and processes, additional satellite datasets of ocean currents, evaporation/precipitation fluxes, and wind speed have been super-imposed. Currently, the main focus of the study deals with the exploitation of these TS diagrams as a prognostic tool to derive water masses formation areas. Firstly, following the approach described in [8], the surface
Evolution of Near-surface Flows Inferred from High-resolution Ring-diagram Analysis
Bogart, Richard S; Baldner,; Basu, Sarbani
2015-01-01
Ring-diagram analysis of acoustic waves observed at the photosphere can provide a relatively robust determination of the sub-surface flows at a particular time under a particular region. The depth of penetration of the waves is related to the size of the region, hence the depth extent of the measured flows is inversely proportional to the spatial resolution. Most ring-diagram analysis has focused on regions of extent ~15{\\deg} (180 Mm) or more in order to provide reasonable mode sets for inversions. HMI data analysis also provides a set of ring fit parameters on a scale three times smaller. These provide flow estimates for the outer 1% (7 Mm) of the Sun only, with very limited depth resolution, but with spatial resolution adequate to map structures potentially associated with the belts and regions of magnetic activity. There are a number of systematic effects affecting the determination of flows from local helioseismic analysis of regions over different parts of the observable disk, not all well understood. I...
Two-loop snail diagrams: relating neutrino masses to dark matter
Energy Technology Data Exchange (ETDEWEB)
Farzan, Yasaman [Physics school, Institute for Research in Fundamental Sciences (IPM),P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)
2015-05-06
Various mechanisms have been developed to explain the origin of neutrino masses. One of them is radiative mass generation. Two-loop mass generation is of particular interest because the masses and couplings of new particles propagating in the loop can be in the range testable by other experiments and observations. In order for the radiative mass suppression to be reliable, it should be guaranteed that lower loop contributions are suppressed. Based on loop topology and the form of electroweak presentation of the particles propagating in the loop, one can determine whether a lower — and therefore dominant — loop contribution is possible. We present a model based on these general considerations which leads to neutrino masses via a two-loop diagram which we dub as “snail-diagram”. The model has two natural candidates for dark matter one of them being a neutral Dirac fermion which can satisfy the conditions of the thermal freeze-out scenario by annihilation to lepton pairs. We comment on the possibility of explaining the GeV gamma ray excess observed by Fermi-LAT from the region close to the Galaxy Center. We also discuss possible signals at the LHC and at experiments searching for lepton flavor violating rare decays.
Potts Henry WW; Anderson Janet E; Colligan Lacey; Berman Jonathan
2010-01-01
Abstract Background Many quality and safety improvement methods in healthcare rely on a complete and accurate map of the process. Process mapping in healthcare is often achieved using a sequential flow diagram, but there is little guidance available in the literature about the most effective type of process map to use. Moreover there is evidence that the organisation of information in an external representation affects reasoning and decision making. This exploratory study examined whether the...
Directory of Open Access Journals (Sweden)
Potts Henry WW
2010-01-01
Full Text Available Abstract Background Many quality and safety improvement methods in healthcare rely on a complete and accurate map of the process. Process mapping in healthcare is often achieved using a sequential flow diagram, but there is little guidance available in the literature about the most effective type of process map to use. Moreover there is evidence that the organisation of information in an external representation affects reasoning and decision making. This exploratory study examined whether the type of process map - sequential or hierarchical - affects healthcare practitioners' judgments. Methods A sequential and a hierarchical process map of a community-based anti coagulation clinic were produced based on data obtained from interviews, talk-throughs, attendance at a training session and examination of protocols and policies. Clinic practitioners were asked to specify the parts of the process that they judged to contain quality and safety concerns. The process maps were then shown to them in counter-balanced order and they were asked to circle on the diagrams the parts of the process where they had the greatest quality and safety concerns. A structured interview was then conducted, in which they were asked about various aspects of the diagrams. Results Quality and safety concerns cited by practitioners differed depending on whether they were or were not looking at a process map, and whether they were looking at a sequential diagram or a hierarchical diagram. More concerns were identified using the hierarchical diagram compared with the sequential diagram and more concerns were identified in relation to clinical work than administrative work. Participants' preference for the sequential or hierarchical diagram depended on the context in which they would be using it. The difficulties of determining the boundaries for the analysis and the granularity required were highlighted. Conclusions The results indicated that the layout of a process map does
Colligan, Lacey; Anderson, Janet E; Potts, Henry W W; Berman, Jonathan
2010-01-07
Many quality and safety improvement methods in healthcare rely on a complete and accurate map of the process. Process mapping in healthcare is often achieved using a sequential flow diagram, but there is little guidance available in the literature about the most effective type of process map to use. Moreover there is evidence that the organisation of information in an external representation affects reasoning and decision making. This exploratory study examined whether the type of process map - sequential or hierarchical - affects healthcare practitioners' judgments. A sequential and a hierarchical process map of a community-based anti coagulation clinic were produced based on data obtained from interviews, talk-throughs, attendance at a training session and examination of protocols and policies. Clinic practitioners were asked to specify the parts of the process that they judged to contain quality and safety concerns. The process maps were then shown to them in counter-balanced order and they were asked to circle on the diagrams the parts of the process where they had the greatest quality and safety concerns. A structured interview was then conducted, in which they were asked about various aspects of the diagrams. Quality and safety concerns cited by practitioners differed depending on whether they were or were not looking at a process map, and whether they were looking at a sequential diagram or a hierarchical diagram. More concerns were identified using the hierarchical diagram compared with the sequential diagram and more concerns were identified in relation to clinical work than administrative work. Participants' preference for the sequential or hierarchical diagram depended on the context in which they would be using it. The difficulties of determining the boundaries for the analysis and the granularity required were highlighted. The results indicated that the layout of a process map does influence perceptions of quality and safety problems in a process. In
HORIZONTAL FLOWS IN ACTIVE REGIONS FROM RING-DIAGRAM AND LOCAL CORRELATION TRACKING METHODS
Energy Technology Data Exchange (ETDEWEB)
Jain, Kiran; Tripathy, S. C.; Komm, R.; Hill, F. [National Solar Observatory, 950 N Cherry Avenue, Tucson, AZ 85719 (United States); Ravindra, B., E-mail: kjain@nso.edu [Indian Institute of Astrophysics, Block 2, Koramangala, Bangaluru, 560034 (India)
2016-01-01
Continuous high-cadence and high spatial resolution Dopplergrams allow us to study subsurface dynamics that may be further extended to explore precursors of visible solar activity on the surface. Since the p-mode power is absorbed in the regions of high magnetic field, the inferences in these regions are often presumed to have large uncertainties. In this paper, using the Dopplergrams from space-borne Helioseismic Magnetic Imager, we compare horizontal flows in a shear layer below the surface and the photospheric layer in and around active regions. The photospheric flows are calculated using the local correlation tracking (LCT) method, while the ring-diagram technique of helioseismology is used to infer flows in the subphotospheric shear layer. We find a strong positive correlation between flows from both methods near the surface. This implies that despite the absorption of acoustic power in the regions of strong magnetic field, the flows inferred from the helioseismology are comparable to those from the surface measurements. However, the magnitudes are significantly different; the flows from the LCT method are smaller by a factor of 2 than the helioseismic measurements. Also, the median difference between the direction of corresponding vectors is 49°.
Horizontal Flows in Active Regions from Ring-diagram and Local Correlation Tracking Methods
Jain, Kiran; Ravindra, B; Komm, R; Hill, F
2015-01-01
Continuous high-cadence and high-spatial resolution Dopplergrams allow us to study sub-surface dynamics that may be further extended to explore precursors of visible solar activity on the surface. Since the p-mode power is absorbed in the regions of high magnetic field, the inferences in these regions are often presumed to have large uncertainties. In this paper, using the Dopplergrams from space-borne Helioseismic Magnetic Imager (HMI), we compare horizontal flows in a shear layer below the surface and the photospheric layer in and around active regions. The photospheric flows are calculated using local correlation tracking (LCT) method while the ring-diagram (RD) technique of helioseismology is used to infer flows in the sub-photospheric shear layer. We find a strong positive correlation between flows from both methods near the surface. This implies that despite the absorption of acoustic power in the regions of strong magnetic field, the flows inferred from the helioseismology are comparable to those from ...
Coriolis mass flow rate meters for low flows
Mehendale, A.
2008-01-01
The accurate and quick measurement of small mass flow rates (~10 mg/s) of fluids is considered an “enabling technology��? in semiconductor, fine-chemical, and food & drugs industries. Flowmeters based on the Coriolis effect offer the most direct sensing of the mass flow rate, and for this reason do
Coriolis mass flow rate meters for low flows
Mehendale, Aditya
2008-01-01
The accurate and quick measurement of small mass flow rates (~10 mg/s) of fluids is considered an "enabling technology" in semiconductor, fine-chemical, and food & drugs industries. Flowmeters based on the Coriolis effect offer the most direct sensing of the mass flow rate, and for this reason do no
Development report, mass flow controller PN 5716068
Taylor, W.
1972-01-01
The design, development, and manufacture of an all mechanical mass flow controller are discussed. A test program was conducted using inert gas as the test medium. The unit controlled the pressure within plus of minus one percent. An analytical method is presented for relating the control pressure error with error in mass flow.
Mass segregation in rich LMC clusters from modelling of deep HST colour-magnitude diagrams
Kerber, L O
2006-01-01
We used the deep colour-magnitude diagrams (CMDs) of five rich LMC clusters (NGC1805, 1818, 1831, 1868, and Hodge14) observed with HST/WFPC2 to derive their present day mass function (PDMF) and its variation with position within the cluster. The PDMF was parameterized as a power law in the available main-sequence mass range of each cluster, typically 0.9 <~ m/M_sun <~ 2.5; its slope was determined at different positions spanning from the very centre out to several core radii. The CMDs in the central regions of the clusters were carefully studied earlier, resulting in accurate age, metallicity, distance modulus, and reddening values. The slope alpha (where Salpeter is 2.35) was determined in annuli by following two distinct methods: 1) a power law fit to the PDMF obtained from the systemic luminosity function (LF); 2) a statistical comparison between observed and model CMDs. In all clusters, significant mass segregation is found from the positional dependence of the PDMF slope: alpha <~ 1.8 for R <...
Johnson, Scott D.; Satchwell, Richard E.
A quasiexperimental study involved 18 male students enrolled in an aircraft systems course at the University of Illinois. The control group of 10 students studied 39 schematic diagrams of aircraft systems. The treatment group of eight students studied the same schematic diagrams plus conceptual diagrams of the systems. Otherwise, the instruction…
Intermediate regime and a phase diagram of red blood cell dynamics in a linear flow
Levant, Michael; Steinberg, Victor
2016-12-01
In this paper we investigate the in vitro dynamics of a single rabbit red blood cell (RBC) in a planar linear flow as a function of a shear stress σ and the dynamic viscosity of outer fluid ηo. A linear flow is a generalization of previous studies dynamics of soft objects including RBC in shear flow and is realized in the experiment in a microfluidic four-roll mill device. We verify that the RBC stable orientation dynamics is found in the experiment being the in-shear-plane orientation and the RBC dynamics is characterized by observed three RBC dynamical states, namely tumbling (TU), intermediate (INT), and swinging (SW) [or tank-treading (TT)] on a single RBC. The main results of these studies are the following. (i) We completely characterize the RBC dynamical states and reconstruct their phase diagram in the case of the RBC in-shear-plane orientation in a planar linear flow and find it in a good agreement with that obtained in early experiments in a shear flow for human RBCs. (ii) The value of the critical shear stress σc of the TU-TT(SW) transition surprisingly coincides with that found in early experiments in spite of a significant difference in the degree of RBC shape deformations in both the SW and INT states. (iii) We describe the INT regime, which is stationary, characterized by strong RBC shape deformations and observed in a wide range of the shear stresses. We argue that our observations cast doubts on the main claim of the recent numerical simulations that the only RBC spheroidal stress-free shape is capable to explain the early experimental data. Finally, we suggest that the amplitude dependence of both θ and the shape deformation parameter D on σ can be used as the quantitative criterion to determine the RBC stress-free shape.
Padé approximants, optimal renormalization scales, and momentum flow in Feynman diagrams
Brodsky, Stanley J.; Gardi, Einan; Karliner, Marek; Samuel, Mark.A.; Brodsky, Stanley J.; Ellis, John; Gardi, Einan; Karliner, Marek; Samuel, Mark. A.
1997-01-01
We show that the Padé Approximant (PA) approach for resummation of perturbative series in QCD provides a systematic method for approximating the flow of momentum in Feynman diagrams. In the large-$\\beta_0$ limit, diagonal PA's generalize the Brodsky-Lepage-Mackenzie (BLM) scale-setting method to higher orders in a renormalization scale- and scheme-invariant manner, using multiple scales that represent Neubert's concept of the distribution of momentum flow through a virtual gluon. If the distribution is non-negative, the PA's have only real roots, and approximate the distribution function by a sum of delta-functions, whose locations and weights are identical to the optimal choice provided by the Gaussian quadrature method for numerical integration. We show how the first few coefficients in a perturbative series can set rigorous bounds on the all-order momentum distribution function, if it is positive. We illustrate the method with the vacuum polarization function and the Bjorken sum rule computed in the large...
Flow angle from intermediate mass fragment measurements
Energy Technology Data Exchange (ETDEWEB)
Rami, F.; Crochet, P.; Dona, R.; De Schauenburg, B.; Wagner, P.; Alard, J.P.; Andronic, A.; Basrak, Z.; Bastid, N.; Belyaev, I.; Bendarag, A.; Berek, G.; Best, D.; Caplar, R.; Devismes, A.; Dupieux, P.; Dzelalija, M.; Eskef, M.; Fodor, Z.; Gobbi, A.; Grishkin, Y.; Herrmann, N.; Hildenbrand, K.D.; Hong, B.; Kecskemeti, J.; Kirejczyk, M.; Korolija, M.; Kotte, R.; Lebedev, A.; Leifels, Y.; Merlitz, H.; Mohren, S.; Moisa, D.; Neubert, W.; Pelte, D.; Petrovici, M.; Pinkenburg, C.; Plettner, C.; Reisdorf, W.; Schuell, D.; Seres, Z.; Sikora, B.; Simion, V.; Siwek-Wilczynska, K.; Stoicea, G.; Stockmeir, M.; Vasiliev, M.; Wisniewski, K.; Wohlfarth, D.; Yushmanov, I.; Zhilin, A
1999-02-15
Directed sideward flow of light charged particles and intermediate mass fragments was measured in different symmetric reactions at bombarding energies from 90 to 800 A MeV. The flow parameter is found to increase with the charge of the detected fragment up to Z = 3-4 and then turns into saturation for heavier fragments. Guided by simple simulations of an anisotropic expanding thermal source, we show that the value at saturation can provide a good estimate of the flow angle, {theta}{sub flow}, in the participant region. It is found that {theta}{sub flow} depends strongly on the impact parameter. The excitation function of {theta}{sub flow} reveals striking deviations from the ideal hydrodynamical scaling. The data exhibit a steep rise of {theta}{sub flow} to a maximum at around 250 - 400 A MeV, followed by a moderate decrease as the bombarding energy increases further.
Solids flow diagram of a CFB riser using Geldart B-type powders
Institute of Scientific and Technical Information of China (English)
Shiva Mahmoudi; Chian Wen Chan; Anke Brems; Jonathan Seville; Jan Baeyens
2012-01-01
Riser operating modes are vital to designing a circulating fluidized bed (CFB) reactor for a required process of either a gas-solid or a gas-catalytic nature.Different operating modes provide different solids' residence times and mixing behaviors,which define the reactions' efficiency and yield.The literature demonstrates distinct operating modes resulting from observed differences in slip factors and the range of particle velocities and their associated residence time distribution.The present research uses positron emission particle tracking (PEPT) in a riser of B-type bed material to determine the different operating modes by measuring (i) particle velocities and residence time distribution,(ii) population densities of these particles in the cross-sectional area of the riser,and (iii) solids flow pattern at the bottom of the riser.Data treatment defines four distinct solids hold-up regimes in the riser and proposes a “phase diagram” depicting the existence of the different operating modes (dilute,dense,core-annulus and combined) as a function of the superficial gas velocity and solids circulation flux in the riser.The delineated regimes have good agreement with available literature data and known industrial operations.Comparison with literature data for risers using A-type powders is also fair.The diagram enables CFB designers to better delineate operating characteristics.
Directory of Open Access Journals (Sweden)
Vinda Nur Fitriana
2016-10-01
Full Text Available This study aims to determine differences in higher order thinking skills and science process skills of students learn who use guided inquiry learning with Flow Diagram strategy and guided inquiry learning. The research design uses quasi-experimental with Pretest-Posttest Control Group Design. The population in this study were students of class X MIA SMA Negeri 1 Kalitidu the academic year 2015/2016. The sample used in this research is class X MIA 4 as an experimental class and class X MIA 2 as the control class with a total of 2 class of 64 students. Instruments used include high-level thinking skills tests and observation sheets science process skills of students. Data analysis technique used is the multivariate analysis (MANOVA at the 5% significance level with SPSS 17.0 for Windows. Based on the analysis obtained the following results. (1 There is the influence of higher-order thinking skills to learn to use guided inquiry learning with Flow Diagram strategy (0.000 <0.05; (2 There is the influence of science process skills that students learn to use guided inquiry learning strategy with Flow Diagram strategy (0.000 <0.05. Penelitian ini bertujuan untuk mengetahui perbedaan keterampilan berpikir tingkat tinggi dan keterampilan proses sains siswa yang belajar menggunakan pembelajaran inkuiri terbimbing dengan strategi Flow Diagram dan pembelajaran inkuiri terbimbing. Rancangan penelitian ini menggunakan kuasi eksperimen dengan Pretest-Postest Control Group Design. Populasi dalam penelitian ini adalah siswa kelas X MIA SMA Negeri 1 Kalitidu tahun ajaran 2015/2016. Sampel yang digunakan dalam penelitian ini, yaitu kelas X MIA 4 sebagai kelas eksperimen dan kelas X MIA 2 sebagai kelas kontrol dengan keseluruhan siswa dari 2 kelas sebanyak 64 siswa. Instrumen yang digunakan meliputi tes keterampilan berpikir tingkat tinggi dan lembar observasi keterampilan proses sains siswa. Teknik analisis data yang digunakan adalah dengan analisis multivarian
Mass Dependence of Disappearance of Transverse Flow
Sood, A D; Sood, Aman D.; Puri, Rajeev K.
2004-01-01
A complete theoretical study is presented for the disappearance of flow, for the first time, by analyzing 15 reactions with masses between 47 and 476 units. We demonstrate that the effect of nucleon-nucleon cross-section reduces to insignificant level for heavier colliding nuclei in agreement with previous studies. A stiff equation of state with nucleon-nucleon cross-sections of 35-40 mb is able to explain all the measured balance energies within few percent. A power law is also given for the mass dependence of the disappearance of flow which is in excellent agreement with experimental data.
Statistical tweaks and flow scale from masses
Datta, Saumen; Lahiri, Anirban; Majumdar, Pushan
2016-01-01
We compare lattice scales determined from the vector meson mass and the Wilson flow scale w_0 in QCD with two-flavours of rooted naive staggered fermions over a wide range of lattice spacing and quark mass. We find that the distributions of meson correlation functions are non-Gaussian. We modify the statistical analysis to take care of the non-Gaussianity. Current day improvements in the statistical quality of data on hadron correlations further allow us to simplify certain aspects of the analysis of masses. We examine these changes through the analysis of pions and apply them to the vector meson. We compare the flow scale determined using the rho mass with that using Lambda_{MSbar}.
Development of the Functional Flow Block Diagram for the J-2X Rocket Engine System
White, Thomas; Stoller, Sandra L.; Greene, WIlliam D.; Christenson, Rick L.; Bowen, Barry C.
2007-01-01
The J-2X program calls for the upgrade of the Apollo-era Rocketdyne J-2 engine to higher power levels, using new materials and manufacturing techniques, and with more restrictive safety and reliability requirements than prior human-rated engines in NASA history. Such requirements demand a comprehensive systems engineering effort to ensure success. Pratt & Whitney Rocketdyne system engineers performed a functional analysis of the engine to establish the functional architecture. J-2X functions were captured in six major operational blocks. Each block was divided into sub-blocks or states. In each sub-block, functions necessary to perform each state were determined. A functional engine schematic consistent with the fidelity of the system model was defined for this analysis. The blocks, sub-blocks, and functions were sequentially numbered to differentiate the states in which the function were performed and to indicate the sequence of events. The Engine System was functionally partitioned, to provide separate and unique functional operators. Establishing unique functional operators as work output of the System Architecture process is novel in Liquid Propulsion Engine design. Each functional operator was described such that its unique functionality was identified. The decomposed functions were then allocated to the functional operators both of which were the inputs to the subsystem or component performance specifications. PWR also used a novel approach to identify and map the engine functional requirements to customer-specified functions. The final result was a comprehensive Functional Flow Block Diagram (FFBD) for the J-2X Engine System, decomposed to the component level and mapped to all functional requirements. This FFBD greatly facilitates component specification development, providing a well-defined trade space for functional trades at the subsystem and component level. It also provides a framework for function-based failure modes and effects analysis (FMEA), and a
Development of the Functional Flow Block Diagram for the J-2X Rocket Engine System
White, Thomas; Stoller, Sandra L.; Greene, WIlliam D.; Christenson, Rick L.; Bowen, Barry C.
2007-01-01
The J-2X program calls for the upgrade of the Apollo-era Rocketdyne J-2 engine to higher power levels, using new materials and manufacturing techniques, and with more restrictive safety and reliability requirements than prior human-rated engines in NASA history. Such requirements demand a comprehensive systems engineering effort to ensure success. Pratt & Whitney Rocketdyne system engineers performed a functional analysis of the engine to establish the functional architecture. J-2X functions were captured in six major operational blocks. Each block was divided into sub-blocks or states. In each sub-block, functions necessary to perform each state were determined. A functional engine schematic consistent with the fidelity of the system model was defined for this analysis. The blocks, sub-blocks, and functions were sequentially numbered to differentiate the states in which the function were performed and to indicate the sequence of events. The Engine System was functionally partitioned, to provide separate and unique functional operators. Establishing unique functional operators as work output of the System Architecture process is novel in Liquid Propulsion Engine design. Each functional operator was described such that its unique functionality was identified. The decomposed functions were then allocated to the functional operators both of which were the inputs to the subsystem or component performance specifications. PWR also used a novel approach to identify and map the engine functional requirements to customer-specified functions. The final result was a comprehensive Functional Flow Block Diagram (FFBD) for the J-2X Engine System, decomposed to the component level and mapped to all functional requirements. This FFBD greatly facilitates component specification development, providing a well-defined trade space for functional trades at the subsystem and component level. It also provides a framework for function-based failure modes and effects analysis (FMEA), and a
Two-state shear diagrams for complex fluids in shear flow
1999-01-01
The possible "phase diagrams'' for shear-induced phase transitions between two phases are collected. We consider shear-thickening and shear-thinning fluids, under conditions of both common strain rate and common stress in the two phases, and present the four fundamental shear stress vs. strain rate curves and discuss their concentration dependence. We outline how to construct more complicated phase diagrams, discuss in which class various experimental systems fall, and sketch how to reconstru...
Mass flow meter of the Coriolis type
Mehendale, A.; Lötters, Joost Conrad; Lotters, Joost Conrad; Zwikker, Jan Marinus
2006-01-01
A mass flowmeter of the Coriolis type with a tube that forms a mechanically closed loop through which a medium flows during operation, and with excitation means for causing the loop to rotate in an oscillatory mode about an axis of rotation during operation. The loop has a starting point and an end
Valamin, A. E.; Kultyshev, A. Yu.; Shibaev, T. L.; Gol'dberg, A. A.; Stepanov, M. Yu.
2016-11-01
A T-250/300-240 turbine (currently known as T-250/300-23.5), which is operated at 31 steam turbine plants, is the largest in the world extraction turbine (by the heating extraction load) and one of the largest by the nominal capacity. All steam turbine plants equipped with T-250/300-23.5 turbines of different modifications are operated in large cities of Russia and the neighboring countries covering a significant part of the needs of cities for the electric power and almost fully supplying them with heat power. The design life of a significant part of the operated steam turbine plants of this family is either expired or almost expired. It refers to both the turbine unit (including a turbine and a generator) and the turbine plant equipment. For steam turbine plants equipped with T-250/300-23.5 turbines, which were initially designed and mounted for work with deaerators at electric power stations, the heat flow diagrams with and without a deaerator were compared. The main advantages and disadvantages of each scheme were shown. It was concluded that, for the newly constructed power units with supercritical steam parameters, it is preferable to use the heat flow diagram without a deaerator; for the upgraded blocks, if there are no objective reasons for the removal of a deaerator, it is recommended to keep the existing heat flow diagram of a turbine plant.
Gaseous Nitrogen Orifice Mass Flow Calculator
Ritrivi, Charles
2013-01-01
The Gaseous Nitrogen (GN2) Orifice Mass Flow Calculator was used to determine Space Shuttle Orbiter Water Spray Boiler (WSB) GN2 high-pressure tank source depletion rates for various leak scenarios, and the ability of the GN2 consumables to support cooling of Auxiliary Power Unit (APU) lubrication during entry. The data was used to support flight rationale concerning loss of an orbiter APU/hydraulic system and mission work-arounds. The GN2 mass flow-rate calculator standardizes a method for rapid assessment of GN2 mass flow through various orifice sizes for various discharge coefficients, delta pressures, and temperatures. The calculator utilizes a 0.9-lb (0.4 kg) GN2 source regulated to 40 psia (.276 kPa). These parameters correspond to the Space Shuttle WSB GN2 Source and Water Tank Bellows, but can be changed in the spreadsheet to accommodate any system parameters. The calculator can be used to analyze a leak source, leak rate, gas consumables depletion time, and puncture diameter that simulates the measured GN2 system pressure drop.
Evolution of the Near-surface Flows Inferred from High-resolution Ring-diagram Analysis of HMI Data
Bogart, Richard S.; Baldner, Charles; Basu, Sarbani
2014-06-01
Ring-diagram analysis of acoustic waves observed at the photosphere provides in principle a relatively robust determination of the sub-surface flows at a particular time under a particular region. The depth of penetration of the waves is related to the size of the region, hence the depth extent of the measured flows is inversely proportional to the spatial resolution. Most ring-analysis has focused on regions of extent ~15 deg (200 Mm) or more in order to provide reasonable mode sets for inversions. The HMI analysis pipeline however also provides a set of ring fit parameters on a scale three times smaller. These provide flow estimates for the outer 1% (7 Mm) of the Sun only, with very limited depth resolution, but with spatial resolution adequate to map structures.potentially associated with the belts and regions of magnetic activity. There are a number of systematic effects affecting the determination of flows from local helioseismic analysis of regions over different parts of the observable disc, not all well-understood. In this study we characterize those systematic effects with higher spatial resolution. This enable us to remove them more effectively as we map the temporal and spatial evolution of the flows, leaving open the question of their mean structure which is most affected by the systematics. We present results for the ring-diagram determination of the flow anomalies corresponding to the torsional oscillation pattern in differential rotation and analogous patterns in the meridional cell structure over the early part of the current solar cycle observed by HMI.
Effects of Density-Dependent Quark Mass on Phase Diagram of Color-Flavor-Locked Quark Matter
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
Considering the density dependence of quark mass, we investigate the phase transition between the (unpaired) strange quark matter and the color-flavor-locked matter, which are supposed to be two candidates for the ground state of strongly interacting matter. We find that if the current mass of strange quark ms is small, the strange quark matter remains stable unless the baryon density is very high. If ms is large, the phase transition from the strange quark matter to the color-flavor-locked matter in particular to its gapless phase is found to be different from the results predicted by previous works. A complicated phase diagram of three-flavor quark matter is presented, in which the color-flavor-locked phase region is suppressed for moderate densities.
Exploring the phase diagram of fully turbulent Taylor–Couette flow
Ostilla Monico, Rodolfo; Poel, van der Erwin P.; Verzicco, Roberto; Grossmann, Siegfried; Lohse, Detlef
2014-01-01
Direct numerical simulations of Taylor–Couette flow, i.e. the flow between two coaxial and independently rotating cylinders, were performed. Shear Reynolds numbers of up to 3×10 5 , corresponding to Taylor numbers of Ta=4.6×10 10 , were reached. Effective scaling laws for the torque are presented.
CFFF low mass flow DCW generator operation
Lineberry, J. T.; Galanga, F. L.; Frazier, J. W.
1986-01-01
A summary of testing of the low mass flow diagonal conducting sidewall MHD generator in the CFFF is given. These summaries include details of the powered generator tests conducted during the 1985 LMF4 test series. A presentation of experimental generator electrical data collected during these tests is included. The quality of these data is discussed and a review of representative data presentations is made as a means of identifying phenomena associated with coal-fired MHD generators. Unique characteristics of coal slag effects upon electrical performance are seen in the voltage profiles and power characteristics for the generator. Fundamental theoretical analyses of the generator are used to qualify the levels of generator performance that were demonstrated during testing. These analyses are directed at isolating possible sources that have caused performance deficiencies and anomalies seen in the test data.
Tsuji; Rey
2000-12-01
A generalized theory that includes short-range elasticity, long-range elasticity, and flow effects is used to simulate and characterize the shear flow of liquid crystalline materials as a function of the Deborah (De) and Ericksen (Er) numbers in the presence of fixed planar director boundary conditions; the results are also interpreted as a function of the ratio R between short-range and long-range elasticity. The results are effectively summarized into rheological phase diagrams spanned by De and Er, and also by R and Er, where the stability region of four distinct flow regimes are indicated. The four regimes for planar (two-dimensional orientation) shear flow are (1) the elastic-driven steady state, (2) the composite tumbling-wagging periodic state, (3) the wagging periodic state, and (4) the viscous-driven steady state. The coexistence of the four regimes at a quacritical point is shown to be due to the emergence of a defect structure. The origin, the significant steady and dynamical features, and the transitions between these regimes are thoroughly characterized and analyzed. Quantitative and qualitative comparisons between the present complete model predictions and those obtained from the classical theories of nematodynamics (Leslie-Ericksen and Doi theories) are presented and the main physical mechanisms that drive the observed deviations between the predictions of these models are identified. The presented results fill the previously existing gap between the classical Leslie-Ericksen theory and the Doi theory, and present a unified description of nematodynamics.
Jorissen, A; Famaey, B; Van Eck, S
2009-01-01
This paper is the third one in a series devoted to studying the properties of binaries involving M giants. We use a new set of orbits to construct the first (e-logP) diagram of an extensive sample of M giant binaries, to obtain their mass-function distribution, and to derive evolutionary constraints for this class of binaries and related systems. The orbital properties of binaries involving M giants were analysed and compared with those of related families of binaries (K giants, post-AGB stars, barium stars, Tc-poor S stars). The orbital elements of post-AGB stars and M giants are not different, which may very indicate that, for the considered sample of post-AGB binaries, the post-AGB star left the AGB at quite an early stage (M4 or so). Neither are the orbital elements of post-mass-transfer binaries like barium stars very different from those of M giants, suggesting that the mass transfer did not alter the orbital elements much, contrary to current belief. Finally, we show that binary systems with e < 0.4...
Jefferys, S.; Johnson, W.; Lewis, R.; Rich, R.
1981-01-01
This specification establishes the requirements, concepts, and preliminary design for a set of software known as the IGDS/TRAP Interface Program (ITIP). This software provides the capability to develop at an Interactive Graphics Design System (IGDS) design station process flow diagrams for use by the NASA Coal Gasification Task Team. In addition, ITIP will use the Data Management and Retrieval System (DMRS) to maintain a data base from which a properly formatted input file to the Time-Line and Resources Analysis Program (TRAP) can be extracted. This set of software will reside on the PDP-11/70 and will become the primary interface between the Coal Gasification Task Team and IGDS, DMRS, and TRAP. The user manual for the computer program is presented.
Venaille, Antoine
2010-01-01
Using explicit analytical computations, generic occurrence of inequivalence between two or more statistical ensembles is obtained for a large class of equilibrium states of two-dimensional and geophysical turbulent flows. The occurrence of statistical ensemble inequivalence is shown to be related to previously observed phase transitions in the equilibrium flow topology. We find in these turbulent flow equilibria, two mechanisms for the appearance of ensemble equivalences, that were not observed in any physical systems before. These mechanisms are associated respectively with second-order azeotropy (simultaneous appearance of two second-order phase transitions), and with bicritical points (bifurcation from a first-order to two second-order phase transition lines). The important roles of domain geometry, of topography, and of a screening length scale (the Rossby radius of deformation) are discussed. It is found that decreasing the screening length scale (making interactions more local) surprisingly widens the r...
McDonald, Sandra A; Velasco, Elizabeth; Ilasi, Nicholas T
2010-12-01
Pfizer, Inc.'s Tissue Bank, in conjunction with Pfizer's BioBank (biofluid repository), endeavored to create an overarching internal software package to cover all general functions of both research facilities, including sample receipt, reconciliation, processing, storage, and ordering. Business process flow diagrams were developed by the Tissue Bank and Informatics teams as a way of characterizing best practices both within the Bank and in its interactions with key internal and external stakeholders. Besides serving as a first step for the software development, such formalized process maps greatly assisted the identification and communication of best practices and the optimization of current procedures. The diagrams shared here could assist other biospecimen research repositories (both pharmaceutical and other settings) for comparative purposes or as a guide to successful informatics design. Therefore, it is recommended that biorepositories consider establishing formalized business process flow diagrams for their laboratories, to address these objectives of communication and strategy.
Energy Technology Data Exchange (ETDEWEB)
Scheurer, K.; Baier, U.
2001-07-01
This study supplements a series of studies carried out under the 'Energy 2000' programme and its follow-up 'SwissEnergy' on the energy potential of biomass in Switzerland. This study compiles data from existing studies and statistics and presents them as detailed mass and energy flow diagrams. The findings of the study confirm that the most important biomass fluxes are generated by animal feed stuffs and manure and that these represent an important potential for use as a source of energy. The authors state that in the foodstuffs and wood/paper industries a high level of sustainability in resource usage has been attained and that the largest losses in mass and energy flows can be found in livestock breeding and human biomass consumption.
Vibration isolation for Coriolis Mass-Flow meters
van de Ridder, Bert
2015-01-01
A Coriolis Mass-Flow Meter (CMFM) is an active device based on the Coriolis force principle for direct mass-flow measurements, with high accuracy, range-ability and repeatability. The working principle of a CMFM is as follows: a fluid conveying tube is actuated to oscillate at a low amplitude. A flu
Vibration isolation for Coriolis Mass-Flow meters
van de Ridder, Bert
2015-01-01
A Coriolis Mass-Flow Meter (CMFM) is an active device based on the Coriolis force principle for direct mass-flow measurements, with high accuracy, range-ability and repeatability. The working principle of a CMFM is as follows: a fluid conveying tube is actuated to oscillate at a low amplitude. A
Evaluation of a mass flow sensor at a gin
As part of a system to optimize the cotton ginning process, a custom-built mass flow sensor was evaluated at USDA-ARS Cotton Ginning Research Unit at Stoneville, Mississippi. The mass flow sensor was fabricated based on the principle of the sensor patented by Thomasson and Sui. The optical and ele...
Vibration isolation for Coriolis Mass-Flow meters
Ridder, van de Lubbert
2015-01-01
A Coriolis Mass-Flow Meter (CMFM) is an active device based on the Coriolis force principle for direct mass-flow measurements, with high accuracy, range-ability and repeatability. The working principle of a CMFM is as follows: a fluid conveying tube is actuated to oscillate at a low amplitude. A flu
A novel concept of measuring mass flow rates using flow induced stresses
Indian Academy of Sciences (India)
P I Jagad; B P Puranik; A W Date
2015-08-01
Measurement of mass flow rate is important for automatic control of the mass flow rate in many industries such as semiconductor manufacturing and chemical industry (for supply of catalyst to a reaction). In the present work, a new concept for direct measurement of mass flow rates which does not depend on the volumetric flow rate measurement and obviates the need for the knowledge of density is proposed from the measurement of the flow induced stresses in a substrate. The concept is formulated by establishing the relationship between the mass flow rate and the stress in the substrate. To this end, the flow field and the stress field in the substrate are evaluated simultaneously using a numerical procedure and the necessary correlations are derived. A least squares based procedure is used to derive the mass flow rate from the correlations as a function of the stress in the substrate.
Buoyancy induced MHD transient mass transfer flow with thermal radiation
Directory of Open Access Journals (Sweden)
N. Ahmed
2016-09-01
Full Text Available The problem of a transient MHD free convective mass transfer flow past an infinite vertical porous plate in presence of thermal radiation is studied. The fluid is considered to be a gray, absorbing-emitting radiating but non-scattered medium. Analytical solutions of the equations governing the flow problem are obtained. The effects of mass transfer, suction, radiation and the applied magnetic field on the flow and transport characteristics are discussed through graphs.
Micro Coriolis mass flow sensor for chemical micropropulsion systems
Wiegerink, Remco J.; Lammerink, Theodorus S.J.; Groenesteijn, Jarno; Dijkstra, Pieter J.; Lötters, Joost Conrad
2012-01-01
We have designed a micromachined micro Coriolis flow sensor for the measurement of hydrazine (N2H4, High Purity Grade) propellant flow in micro chemical propulsion systems. The sensor measures mass flow up to 10 mg/s for a single thruster or up to 40 mg/s for four thrusters. The sensor will first be
Qiu, Shanwen
2013-09-01
In this article, we propose a new exact and grid-free numerical scheme for computing solutions associated with an hybrid traffic flow model based on the Lighthill-Whitham-Richards (LWR) partial differential equation, for a class of fundamental diagrams. In this hybrid flow model, the vehicles satisfy the LWR equation whenever possible, and have a constant acceleration otherwise. We first propose a mathematical definition of the solution as a minimization problem. We use this formulation to build a grid-free solution method for this model based on the minimization of component function. We then derive these component functions analytically for triangular fundamental diagrams, which are commonly used to model traffic flow. We also show that the proposed computational method can handle fixed or moving bottlenecks. A toolbox implementation of the resulting algorithm is briefly discussed, and posted at https://dl.dropbox.com/u/1318701/Toolbox.zip. © 2013 Elsevier Ltd.
A mechanical erosion model for two-phase mass flows
Pudasaini, Shiva P
2016-01-01
Erosion, entrainment and deposition are complex and dominant, but yet poorly understood, mechanical processes in geophysical mass flows. Here, we propose a novel, process-based, two-phase, erosion-deposition model capable of adequately describing these complex phenomena commonly observed in landslides, avalanches, debris flows and bedload transport. The model is based on the jump in the momentum flux including changes of material and flow properties along the flow-bed interface and enhances an existing general two-phase mass flow model (Pudasaini, 2012). A two-phase variably saturated erodible basal morphology is introduced and allows for the evolution of erosion-deposition-depths, incorporating the inherent physical process including momentum and rheological changes of the flowing mixture. By rigorous derivation, we show that appropriate incorporation of the mass and momentum productions or losses in conservative model formulation is essential for the physically correct and mathematically consistent descript...
Assessment for hydrodynamic masses of HANARO flow tubes
Energy Technology Data Exchange (ETDEWEB)
Ryu, Jeong Soo; Cho, Yeong Garp; Kim, Doo Kie; Woo, Jong Sug; Park, Jin Ho
2000-06-01
The effect of hydrodynamic masses is investigated in dynamic characteristics and seismic response analyses of the submerged HANARO hexagonal flow tubes. Consistent hydrodynamic masses of the surrounding water are evaluated by the prepared program using the finite element method, in which arbitrary cross-sections of submerged structures and boundary conditions of the surrounding fluid can be considered. Also lumped hydrodynamic masses are calculated using simple formula applied to hexagonal flow tubes in the infinite fluid. Modal analyses and seismic response spectrum analyses were performed using hydrodynamic masses obtained by the finite element method and the simple formula. The results of modal analysis were verified by comparing the results measured from modal tests. And the displacement results of the seismic response spectrum analysis were assessed by comparing the consistent and the lumped hydrodynamic masses obtained by various methods. Finally practical criteria based on parametric studies are proposed as the lumped hydrodynamic masses for HANARO flow tubes.
Port and EGR Mass Flow Sensors
DEFF Research Database (Denmark)
Hendricks, Elbert
1998-01-01
The note documents briefly work done on what is thought to be a new method of measurement of the pulsating flow in the intake port ot and SI engine and in the EGR returen line. The work reviewed has been carried out in close cooperation with Civ. Ing. Michael Føns, Civ. Ing. Christian Jepsen...
Study of quark flow in exclusive reactions at 90 degrees in the center of mass (AGS E838)
Appel, R.; White, C.; Courant, H.; Fang, G.; Heller, K. J.; Johns, K.; Marshak, M. L.; Shupe, M.; Barton, D. S.; Bunce, G.; Carroll, A. S.; Gushue, S.; Kmit, M.; Lowenstein, D. I.; Makdisi, Y. I.; Heppelmann, S.; Ma, X.; Russell, J. J.
1995-07-01
We report a study of quark flow in 20 exclusive reactions measured at Brookhaven National Laboratory's AGS with a beam momentum of 5.9 GeV/c at 90° in the center of mass. This experiment confirms the strong quark flow reaction mechanism dependence of two-body hadron scattering at large angles seen at 9.9 GeV/c. Large differences in cross sections for different reactions are consistent with the dominance of quark interchange in these 90° reactions, and indicate that pure gluon exchange and quark/antiquark annihilation diagrams are less important.
Kosaka, Ryo; Nishida, Masahiro; Maruyama, Osamu; Yamane, Takashi
2011-01-01
Blood flow should be measured to monitor conditions of patients with implantable artificial hearts continuously and noninvasively. We have developed a noninvasive miniaturized mass-flow meter using a curved cannula for an axial flow blood pump. The mass-flow meter utilized centrifugal force generated by the mass-flow rate in the curved cannula. Two strain gauges served as sensors. Based on the numerical analysis, the first gauge, attached to the curved area, measured static pressure and centrifugal force, and the second, attached to the straight area, measured static pressure for static pressure compensation. The mass-flow rate was determined by the differences in output from the two gauges. To compensate for the inertia force under the pulsatile flow, a 0.75-Hz low-pass filter was added to the electrical circuit. In the evaluation tests, numerical analysis and an actual measurement test using bovine blood were performed to evaluate the measurement performances. As a result, in the numerical analysis, the relationship between the differential pressure caused by centrifugal force and the flow rate was verified. In the actual measurement test, measurement error was less than ± 0.5 L/min, and the time delay was 0.12 s. We confirmed that the developed mass-flow meter was able to measure mass-flow rate continuously and noninvasively.
Parametric amplification in a micro Coriolis mass flow sensor
Groenesteijn, J.; Droogendijk, H.; Wiegerink, R.J.; Lammerink, T.S.J.; Lötters, J.C.; Sanders, R.G.P.; Krijnen, G.J.M.
2014-01-01
We report on the application of parametric amplification to a micro Coriolis mass flow sensor. We demonstrate that this mechanism allows for reduction of the system's power dissipation while retaining sensitivity to flow. By reducing this power dissipation, less heat will be transferred to the fluid
Colwell, Morris A
1976-01-01
Electronic Diagrams is a ready reference and general guide to systems and circuit planning and in the preparation of diagrams for both newcomers and the more experienced. This book presents guidelines and logical procedures that the reader can follow and then be equipped to tackle large complex diagrams by recognition of characteristic 'building blocks' or 'black boxes'. The goal is to break down many of the barriers that often seem to deter students and laymen in learning the art of electronics, especially when they take up electronics as a spare time occupation. This text is comprised of nin
Fiber optic liquid mass flow sensor and method
Korman, Valentin (Inventor); Gregory, Don Allen (Inventor); Wiley, John T. (Inventor); Pedersen, Kevin W. (Inventor)
2010-01-01
A method and apparatus are provided for sensing the mass flow rate of a fluid flowing through a pipe. A light beam containing plural individual wavelengths is projected from one side of the pipe across the width of the pipe so as to pass through the fluid under test. Fiber optic couplers located at least two positions on the opposite side of the pipe are used to detect the light beam. A determination is then made of the relative strengths of the light beam for each wavelength at the at least two positions and based at least in part on these relative strengths, the mass flow rate of the fluid is determined.
Viscous Flow over an Unsteady Shrinking Sheet with Mass Transfer
Institute of Scientific and Technical Information of China (English)
FANG Tie-Gang; ZHANG Ji; YAO Shan-Shan
2009-01-01
The unsteady viscous flow over a continuously shrinking surface with mass suction is studied. The solution is fortunately an exact solution of the unsteady Navier-Stokes equations. Similarity equations are obtained through the application of similarity transformation techniques. Numerical techniques are used to solve the similarity equations for different values of the mass suction parameters" and the unsteadiness parameters. Results show that multiple solutions exist for a certain range of mass suction and unsteadiness parameters. Quite different flow behaviour is observed for an unsteady shrinking sheet from an unsteady stretching sheet.
Laboratory and field trials of Coriolis mass flow metering for three-phase flow measurement
Zhou, Feibiao; Henry, Manus; Tombs, Michael
2014-04-01
A new three-phase flow metering technology is discussed in this paper, which combines Coriolis mass flow and water cut readings and without applying any phase separation [1]. The system has undergone formal laboratory trials at TUV NEL (National Engineering Laboratory), UK and at VNIIR (National Flow Laboratory), Kazan, Russia; a number of field trials have taken place in Russia. Laboratory trial results from the TUV NEL will be described in detail. For the 50mm (2") metering system, the total liquid flow rate ranged from 2.4 kg/s up to 11 kg/s, the water cut ranged from 0% to 100%, and the gas volume fraction (GVF) from 0 to 50%. In a formally observed trial, 75 test points were taken at a temperature of approximately 40 °C and with a skid inlet pressure of approximately 350 kPa. Over 95% of the test results fell within the desired specification, defined as follows: the total (oil + water) liquid mass flow error should fall within ± 2.5%, and the gas mass flow error within ± 5.0%. The oil mass flow error limit is ± 6.0% for water cuts less than 70%, while for water cuts between 70% and 95% the oil mass flow error limit is ± 15.0%. These results demonstrate the potential for using Coriolis mass flow metering combined with water cut metering for three-phase (oil/water/gas) measurement.
Nanouris, N.; Kalimeris, A.; Antonopoulou, E.; Rovithis-Livaniou, H.
2011-11-01
Context. The credibility of an O-C diagram analysis is investigated when long-term processes are examined in binary systems. The morphology of period and O-C diagrams is thoroughly explored when mass loss and magnetic braking, induced by stellar winds, drive the orbital evolution of late-type detached binaries. Conditions are specified that determine which process dominates. Aims: Our objective is to determine the minimum time intervals that observations are expected to span for a physical mechanism to be detectable by means of an O-C diagram analysis. Computations for various values that account for the noise level and the orbital period are performed to find out to which degree these affect the inferred intervals. Methods: Generalized dot{J-dot{P}} relations that govern the orbital evolution of a binary system are set and solved analytically to determine in a closed form the period and the function expected to represent the respective O-C variations. Semi-empirical relations adapting mass loss and magnetic braking processes for single cool stars are adopted and properly modified to be consistent with the latest observational constraints. A standard Newton-Raphson numerical procedure is then employed to estimate the minimum temporal range over which a specific mechanism is rendered measurable. Results: Mass loss rates comparable to or greater than -10-9 M⊙ yr-1 are measurable for typical noise levels of the O-C diagrams when the data span more than a century. Magnetic braking was proved to be very sensitive on the orbital period and on the braking law adopted for inference. It is expected to be detectable in current O-C diagrams of very short-period binaries only, for others it needs at least two centuries of observations to confirm its effects safely. Conclusions: Both wind driven mass loss and magnetic braking processes are able to drive the orbital evolution of short-period detached binaries (Porb1d) in amounts traced on human timescales. There are also
Rose, Matthew
2004-01-01
Matthew Rose worked at the Naval Postgraduate School as a graphic designer from February 2002-November 2011. His work for NPS included logos, brochures, business packs, movies/presentations, posters, the CyberSiege video game and many other projects. This material was organized and provided by the artist, for inclusion in the NPS Archive, Calhoun. Includes these files: Plan_ver.ai; powerline.jpg; SCADA diagram.ai; SCADA diagram.pdf; SCADA diagramsmall.pdf; SCADA2.pdf
Engineering holographic phase diagrams
Chen, Jiunn-Wei; Dai, Shou-Huang; Maity, Debaprasad; Zhang, Yun-Long
2016-10-01
By introducing interacting scalar fields, we tried to engineer physically motivated holographic phase diagrams which may be interesting in the context of various known condensed matter systems. We introduce an additional scalar field in the bulk which provides a tunable parameter in the boundary theory. By exploiting the way the tuning parameter changes the effective masses of the bulk interacting scalar fields, desired phase diagrams can be engineered for the boundary order parameters dual to those scalar fields. We give a few examples of generating phase diagrams with phase boundaries which are strikingly similar to the known quantum phases at low temperature such as the superconducting phases. However, the important difference is that all the phases we have discussed are characterized by neutral order parameters. At the end, we discuss if there exists any emerging scaling symmetry associated with a quantum critical point hidden under the dome in this phase diagram.
Segarra, Guillem; Puopolo, Gerardo; Giovannini, Oscar; Pertot, Ilaria
2015-12-20
The formulation is a significant step in biopesticide development and is an efficient way to obtain consistency in terms of biological control under field conditions. Nonetheless, there is still a lack of information regarding the processes needed to achieve efficient formulation of non spore-forming bacterial biological control agents. In response to this, we propose a flow diagram made up of six steps including selection of growth parameters, checking of minimum shelf life, selection of protective additives, checking that the additives have no adverse effects, validation of the additive mix under field conditions and choosing whether to use additives as co-formulants or tank mix additives. This diagram is intended to provide guidance and decision-making criteria for the formulation of non spore-forming bacterial biological control agents against foliar pathogens. The diagram was then validated by designing an efficient formulation for a Gram-negative bacterium, Lysobacter capsici AZ78, to control grapevine downy mildew caused by Plasmopara viticola. A harvest of 10(10)L. capsici AZ78cellsml(-1) was obtained in a bench top fermenter. The viability of cells decreased by only one order of magnitude after one year of storage at 4°C. The use of a combination of corn steep liquor, lignosulfonate, and polyethyleneglycol in the formulation improved the survival of L. capsici AZ78 cells living on grapevine leaves under field conditions by one order of magnitude. Furthermore, the use of these additives also guaranteed a reduction of 71% in P. viticola attacks. In conclusion, this work presents a straightforward stepwise flow diagram to help researchers develop formulations for biological control agents that are easy to prepare, stable, not phytotoxic and able to protect the microorganims under field conditions.
Jin, Cheng-Jie; Jiang, Rui
2017-02-01
The pedestrian flow dynamics are very complex. Even the fundamental diagrams of uni-directional pedestrian flow exhibit diversity. In the empirical data of Mori-Tsukaguchi and Helbing et al, the flows drop drastically with medium densities and nearly keep constant with high densities, which is different from many other empirical and experimental results. To simulate these special phenomena with cellular automaton (CA) models, we use the new configuration, in which the occupied area of each pedestrian is 0.4 m * 0.2 m. The modeling framework is based on the ITP model, which is a two-process CA model presented in our previous paper, and one new rule is added: when the local density behind is below a threshold, pedestrians prefer to keep a certain front gap. With the simple rule, the new fundamental diagrams can qualitatively coincide with the empirical facts of Mori-Tsukaguchi and Helbing et al. Some other results, including simulation patterns and velocities of pedestrians can further confirm the validity of the new rule, and give some explanations for the diversity of different empirical data. These results are useful contributions for pedestrian flow modeling.
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
According to the mass action law and the coexistence theory of metallic melts, the mass action concentrations of Cu-Mg, Bi-Tl and Ni-Al melts involving compound formation have been calculated. The calculated results show that, except the ultimate case of pure element, when two elements are present in the melts, all structural units (atoms and molecules) without exception will be present in the melts, i.e., their concentrations may change from great to small, but they will not vanish into nothing, and only under such conditions, the calculated results both agree with practice and obey the law of mass action. In view of that over considerable wide composition range, the activities of both elements of the three solid binary alloys mentioned above have been measured, this seems in contradiction with the present relevant phase diagrams, in which the structural units are determined by composition range, so the latter needs further investigation and consideration.
Institute of Scientific and Technical Information of China (English)
Jing Fan; Chong Xie; Jianzheng Jiang
2007-01-01
Measured mass flow rates and streamwise pressure distributions of gas flowing through microchannels were reported by many researchers. Assessment of these data is crucial before they are used in the examination of slip models and numerical schemes, and in the design of microchannel elements in various MEMS devices. On the basis of kinetic solutions of the mass flow rates and pressure distributions in microchannel gas flows, the measured data available are properly normalized and then are compared with each other. The 69 normalized data of measured pressure distributions are in excellent agreement, and 67 of them are within 1 ± 0.05. The normalized data of mass flow-rates ranging between 0.95 and 1 agree well with each other as the inlet Knudsen number Kni ＞ 0.02, but they scat ter between 0.85 and 1.15 as Kni ＜ 0.02 with, to some extent, a very interesting bifurcation trend.
Heat and mass transfer and hydrodynamics in swirling flows (review)
Leont'ev, A. I.; Kuzma-Kichta, Yu. A.; Popov, I. A.
2017-02-01
Research results of Russian and foreign scientists of heat and mass transfer in whirling flows, swirling effect, superficial vortex generators, thermodynamics and hydrodynamics at micro- and nanoscales, burning at swirl of the flow, and technologies and apparatuses with the use of whirling currents for industry and power generation were presented and discussed at the "Heat and Mass Transfer in Whirling Currents" 5th International Conference. The choice of rational forms of the equipment flow parts when using whirling and swirling flows to increase efficiency of the heat-power equipment and of flow regimes and burning on the basis of deep study of the flow and heat transfer local parameters was set as the main research prospect. In this regard, there is noticeable progress in research methods of whirling and swirling flows. The number of computational treatments of swirling flows' local parameters has been increased. Development and advancement of the up to date computing models and national productivity software are very important for this process. All experimental works are carried out with up to date research methods of the local thermoshydraulic parameters, which enable one to reveal physical mechanisms of processes: PIV and LIV visualization techniques, high-speed and infrared photography, high speed registration of parameters of high-speed processes, etc. There is a problem of improvement of researchers' professional skills in the field of fluid mechanics to set adequately mathematics and physics problems of aerohydrodynamics for whirling and swirling flows and numerical and pilot investigations. It has been pointed out that issues of improvement of the cooling system and thermal protection effectiveness of heat-power and heat-transfer equipment units are still actual. It can be solved successfully using whirling and swirling flows as simple low power consumption exposing on the flow method and heat transfer augmentation.
Modelling of convective heat and mass transfer in rotating flows
Shevchuk, Igor V
2016-01-01
This monograph presents results of the analytical and numerical modeling of convective heat and mass transfer in different rotating flows caused by (i) system rotation, (ii) swirl flows due to swirl generators, and (iii) surface curvature in turns and bends. Volume forces (i.e. centrifugal and Coriolis forces), which influence the flow pattern, emerge in all of these rotating flows. The main part of this work deals with rotating flows caused by system rotation, which includes several rotating-disk configurations and straight pipes rotating about a parallel axis. Swirl flows are studied in some of the configurations mentioned above. Curvilinear flows are investigated in different geometries of two-pass ribbed and smooth channels with 180° bends. The author demonstrates that the complex phenomena of fluid flow and convective heat transfer in rotating flows can be successfully simulated using not only the universal CFD methodology, but in certain cases by means of the integral methods, self-similar and analyt...
Oostrom, V. van
2008-01-01
We introduce the unifying notion of delimiting diagram. Hitherto unrelated results such as: Minimality of the internal needed strategy for orthogonal first-order term rewriting systems, maximality of the limit strategy for orthogonal higher-order pattern rewrite systems (with maximality of the strat
Optical measurement of a micro coriolis mass flow sensor
Kristiansen, L.; Mehendale, A.; Brouwer, D.M.; Zwikker, J.M.; Klein, M.E.
2009-01-01
Haneveld [1,2] demonstrated a micro Coriolis mass flow sensor, operating in the measurement range of 0 to 1 g/hr achieving a resolution in the order of 10 mg/hr using a laser vibrometer. Equipped with an integrated capacitive [3] readout the measurement uncertainty amounted to 2% of the full scale r
A 3-dimensional mass conserving element for compressible flows
Fix, G.; Suri, M.
1985-01-01
A variety of finite element schemes has been used in the numerical approximation of compressible flows particularly in underwater acoustics. In many instances instabilities have been generated due to the lack of mass conservation. Two- and three-dimensional elements are developed which avoid these problems.
Micro coriolis mass flow sensor with integrated capacitive readout
Haneveld, J.; Lammerink, T.S.J.; Boer, de M.J.; Wiegerink, R.J.
2009-01-01
We have realized a micromachined micro Coriolis mass flow sensor with integrated capacitive readout to detect the extremely small Coriolis vibration of the sensor tube. A special comb-like detection electrode design eliminates the need for multiple metal layers and sacrificial layer etching methods.
Controlling Surface Roughness to Enhance Mass Flow Rates in Nanochannels
Zimon, Malgorzata; Emerson, David; Reese, Jason
2012-11-01
A very active field of research in fluid mechanics and material science is predicting the behavior of Newtonian fluids flowing over porous media with different wettabilities. Opposite effects have been observed: some state that wall roughness always suppresses fluid-slip, whereas others show that for some cases roughness may reduce the surface friction. In this work, MD simulations were carried out to further investigate physical mechanisms for liquid slip, and factors affecting it. A rough wall was formed by either periodically spaced rectangular protrusions or was represented by a cosine wave. The MD simulations were conducted to study Poiseuille and Couette flow of liquid argon in a nanochannel with hydrophilic kryptonian walls. The effect of wall roughness and interface wettability on the streaming velocity, and the slip-length at the walls, is observed to be significant. Our results show a dependency of mass flow rate on the type of flow and topography of the channel walls. For a fixed magnitude of the driving force, an increase in the mass flow rate, compared to the smooth surface, was observed for the wavy roughness, whereas the opposite effect was observed for Couette flow where a higher slip was obtained for rectangular gaps. The study is funded in the UK by the Engineering and Physical Sciences Research Council.
Djorgovski, S.; Murdin, P.
2000-11-01
Initially introduced as a way to demonstrate the expansion of the universe, and subsequently to determine the expansion rate (the HUBBLE CONSTANT H0), the Hubble diagram is one of the classical cosmological tests. It is a plot of apparent fluxes (usually expressed as magnitudes) of some types of objects at cosmological distances, against their REDSHIFTS. It is used as a tool to measure the glob...
Mass flow-rate control through time periodic electro-osmotic flows in circular microchannels
Chakraborty, Suman; Ray, Subhashis
2008-08-01
The present study is directed towards devising a scientific strategy for obtaining controlled time-periodic mass flow-rate characteristics through the employment of pulsating electric fields in circular microchannels by exploiting certain intrinsic characteristics of periodic electro-osmosis phenomenon. Within the assumption of thin electrical double layers, the governing equations for potential distribution and fluid flow are derived, corresponding to a steady base state and a time-varying perturbed state, by assuming periodic forms of the imposed electrical fields and the resultant velocity fields. For sinusoidal pulsations of the electric field superimposed over its mean, a signature map depicting the amplitudes of the mass flow rate and the electrical field as well as their phase differences is obtained from the theoretical analysis as a function of a nondimensional frequency parameter for different ratios of the characteristic electric double layer thickness relative to the microchannel radius. Distinctive characteristics in the signature profiles are obtained for lower and higher frequencies, primarily attributed to the finite time scale for momentum propagation away from the walls. The signature characteristics, obtained from the solution of the prescribed sinusoidal electric field, are subsequently used to solve the "inverse" problem, where the mass flow rate is prescribed in the form of sinusoidal pulsations and the desired electric fields that would produce the required mass flow-rate variations are obtained. The analysis is subsequently extended for controlled triangular and trapezoidal pulsations in the mass flow rate and the required electric fields are successfully obtained. It is observed that the higher the double layer thickness is in comparison to the channel radius, the more prominent is the deviation of the shape of the required electric field pulsation from the desired transience in the mass flow-rate characteristics. Possible extensions of the
Radiation Effect on Mhd Heat and Mass Transfer Flow over a Shrinking Sheet with Mass Suction
Directory of Open Access Journals (Sweden)
patkar ramesh
2014-01-01
Full Text Available A numerical analysis has been carried out to study the effects radiation and heat source/sink on the steady two dimensional magnetohydrodynamic (MHD boundary layer flow of heat and mass transfer past a shrinking sheet with wall mass suction. In the dynamic system, a uniform magnetic field acts normal to the plane of flow. The governing partial differential equations are transformed into self-similar equations are solved by employing finite difference using the quasilinearization technique. From the analysis it is found that the velocity inside the boundary layer increases with increase of wall mass suction and magnetic field and accordingly the thickness of the momentum boundary layer decreases. The temperature decreases with Hartmann number, Prandtl number, and heat sink parameter and the temperature increases with heat source parameter, radiation parameter. The concentration decreases with an increase of Hartmann number, mass suction parameter, Schmidt number, chemical reaction parameter.
Gas mass derived by infrasound and UV cameras: Implications for mass flow rate
Delle Donne, D.; Ripepe, M.; Lacanna, G.; Tamburello, G.; Bitetto, M.; Aiuppa, A.
2016-10-01
Mass Flow Rate is one of the most crucial eruption source parameter used to define magnitude of eruption and to quantify the ash dispersal in the atmosphere. However, this parameter is in general difficult to be derived and no valid technique has been developed yet to measure it in real time with sufficient accuracy. Linear acoustics has been applied to infrasonic pressure waves generated by explosive eruptions to indirectly estimate the gas mass erupted and then the mass flow rate. Here, we test on Stromboli volcano (Italy) the performance of such methodology by comparing the acoustic derived results with independent gas mass estimates obtained with UV cameras, and constraining the acoustic source by thermal imagery. We show that different acoustic methods give comparable total gas masses in the 2 to 1425 kg range, which are fully consistent with the gas masses derived by UV cameras and previous direct SO2 measurements. We show that total erupted gas mass, estimated by infrasound is not simply a function of the initial pressure, but rather the full infrasonic waveform should be considered. Thermal imagery provides evidence that infrasound is generated during the entire gas thrust phase. We provide examples to show how total gas masses derived by infrasonic signals can be affected by large uncertainties if duration of the signal is neglected. Only when duration of infrasound is included, the best correlation (0.8) with UV cameras and the 1:1 direct linear proportionality is obtained. Our results open new perspective for remotely derived gas mass and mass flow rates from acoustic signals.
Accurate, reliable control of process gases by mass flow controllers
Energy Technology Data Exchange (ETDEWEB)
Hardy, J.; McKnight, T.
1997-02-01
The thermal mass flow controller, or MFC, has become an instrument of choice for the monitoring and controlling of process gas flow throughout the materials processing industry. These MFCs are used on CVD processes, etching tools, and furnaces and, within the semiconductor industry, are used on 70% of the processing tools. Reliability and accuracy are major concerns for the users of the MFCs. Calibration and characterization technologies for the development and implementation of mass flow devices are described. A test facility is available to industry and universities to test and develop gas floe sensors and controllers and evaluate their performance related to environmental effects, reliability, reproducibility, and accuracy. Additional work has been conducted in the area of accuracy. A gravimetric calibrator was invented that allows flow sensors to be calibrated in corrosive, reactive gases to an accuracy of 0.3% of reading, at least an order of magnitude better than previously possible. Although MFCs are typically specified with accuracies of 1% of full scale, MFCs may often be implemented with unwarranted confidence due to the conventional use of surrogate gas factors. Surrogate gas factors are corrections applied to process flow indications when an MFC has been calibrated on a laboratory-safe surrogate gas, but is actually used on a toxic, or corrosive process gas. Previous studies have indicated that the use of these factors may cause process flow errors of typically 10%, but possibly as great as 40% of full scale. This paper will present possible sources of error in MFC process gas flow monitoring and control, and will present an overview of corrective measures which may be implemented with MFC use to significantly reduce these sources of error.
Romans-mass-driven flows on the D2-brane
Guarino, Adolfo; Varela, Oscar
2016-01-01
The addition of supersymmetric Chern-Simons terms to ${\\cal N}=8$ super-Yang-Mills theory in three-dimensions is expected to make the latter flow into infrared superconformal phases. We address this problem holographically by studying the effect of the Romans mass on the D2-brane near-horizon geometry. Working in a consistent, effective four-dimensional setting provided by $D=4$ ${\\cal N}=8$ supergravity with a dyonic $\\textrm{ISO(7)}$ gauging, we verify the existence of a rich web of supersymmetric domain walls triggered by the Romans mass that interpolate between the (four-dimensional description of the) D2-brane and various superconformal phases. We also construct domain walls for which both endpoints are superconformal. While most of our results are numerical, we provide analytic results for the $\\textrm{SU}(3)\\times \\textrm{U}(1)$-invariant flow into an ${\\cal N}=2$ conformal phase recently discovered.
Romans-mass-driven flows on the D2-brane
Energy Technology Data Exchange (ETDEWEB)
Guarino, Adolfo [Nikhef Theory Group,Science Park 105, 1098 XG Amsterdam (Netherlands); Tarrío, Javier [Physique Théorique et Mathématique, Université Libre de Bruxellesand International Solvay Institutes,ULB-Campus Plaine CP231, B-1050 Brussels (Belgium); Varela, Oscar [Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut),Am Mühlenberg 1, D-14476 Potsdam (Germany); Department of Physics, Utah State University,Logan, UT 84322 (United States)
2016-08-30
The addition of supersymmetric Chern-Simons terms to N=8 super-Yang-Mills theory in three-dimensions is expected to make the latter flow into infrared superconformal phases. We address this problem holographically by studying the effect of the Romans mass on the D2-brane near-horizon geometry. Working in a consistent, effective four-dimensional setting provided by D=4N=8 supergravity with a dyonic ISO(7) gauging, we verify the existence of a rich web of supersymmetric domain walls triggered by the Romans mass that interpolate between the (four-dimensional description of the) D2-brane and various superconformal phases. We also construct domain walls for which both endpoints are superconformal. While most of our results are numerical, we provide analytic results for the SU(3)×U(1)-invariant flow into an N=2 conformal phase recently discovered.
14 CFR 25.1443 - Minimum mass flow of supplemental oxygen.
2010-01-01
... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Minimum mass flow of supplemental oxygen... § 25.1443 Minimum mass flow of supplemental oxygen. (a) If continuous flow equipment is installed for use by flight crewmembers, the minimum mass flow of supplemental oxygen required for each...
Compact Mass Flow Meter Based on a Micro Coriolis Flow Sensor
Directory of Open Access Journals (Sweden)
Remco Wiegerink
2013-03-01
Full Text Available In this paper we demonstrate a compact ready-to-use micro Coriolis mass flow meter. The full scale flow is 1 g/h (for water at a pressure drop < 1 bar. It has a zero stability of 2 mg/h and an accuracy of 0.5% reading for both liquids and gases. The temperature drift between 10 and 50 °C is below 1 mg/h/°C. The meter is robust, has standard fluidic connections and can be read out by means of a PC or laptop via USB. Its performance was tested for several common gases (hydrogen, helium, nitrogen, argon and air and liquids (water and isopropanol. As in all Coriolis mass flow meters, the meter is also able to measure the actual density of the medium flowing through the tube. The sensitivity of the measured density is ~1 Hz.m3/kg.
Diffusive heat and mass transfer in oscillatory pipe flow
Brereton, G. J.; Jalil, S. M.
2017-07-01
The enhancement of axial heat and mass transfer by laminar flow oscillation in pipes with axial gradients in temperature and concentration has been studied analytically for the cases of insulated and conducting walls. The axial diffusivity can exceed its molecular counterpart by many orders of magnitude, with a quadratic scaling on the pressure-gradient amplitude and the Prandtl or Schmidt number, and is a bimodal function of oscillatory frequency: quasi-steady behavior at low frequencies and a power-law decay at high frequencies. When the pipe wall is conductive and of sufficient thickness, and the flow oscillation is quasi-steady, the axial diffusivity may be enhanced by a further factor of about ten as a result of increased radial diffusion, for liquid and gas flows in pipes with walls with a wide range of thermal conductivities. Criteria for the wall thickness required to achieve this additional enhancement and for the limits placed on the validity of these solutions by viscous dissipation are also deduced. When the heat transfer per unit flow work achieved by oscillatory pipe flow is contrasted with that of a conventional parallel-flow heat exchanger, it is found to be of comparable size and the ratio of the two is shown to be a function only of the pipe geometry, heat-exchanger mean velocity, and fluid viscosity.
Effective Mass in Rosenbluth-Hinton type zonal flows
Sengupta, W
2016-01-01
An initial radial electric field, $E_r(0)$, in an axisymmetric tokamak, results in geodesic acoustic mode (GAM) oscillations. The GAMs Landau damp, resulting in a much smaller final residual electric field, $E_r(\\infty)$, and accompanying parallel zonal flows (Rosenbluth and Hinton, 1998 PRL 80, 724, hereafter RH). The phenomenon exhibits a large effective mass (inertia due to flows), with an enhancement of order the well-known RH factor. In apparent paradox, the final angular momentum in the RH parallel zonal flow is much smaller than the angular momentum expected from the well-known rapid precession of the trapped particle population in the final electric field. In addition, an effective mass calculated naively based on the rapid trapped particle (TP) precession is much larger than the RH factor. A drift kinetic calculation is presented showing that the mathematical origin of the extra mass factor is a shift, proportional to $E_r$, of the usual energy coordinates in phase space. Importantly, this shift cont...
Rising river flows and glacial mass balance in central Karakoram
Mukhopadhyay, Biswajit; Khan, Asif
2014-05-01
glacial mass balance in central Karakoram is nearly neutral. The rising river flows accompanying non-negative glacier mass balance are consistent with predicted future river flows derived from hydrologic modeling coupled with a climate projection suggesting increasing temperature and precipitation with unchanged glacier covers. This investigation reconciles two apparently contradictory observations namely rising river flows and either zero or slightly positive mass balance of central Karakoram glaciers.
Abolhasani, Milad
Flowing trains of uniformly sized bubbles/droplets (i.e., segmented flows) and the associated mass transfer enhancement over their single-phase counterparts have been studied extensively during the past fifty years. Although the scaling behaviour of segmented flow formation is increasingly well understood, the predictive adjustment of the desired flow characteristics that influence the mixing and residence times, remains a challenge. Currently, a time consuming, slow and often inconsistent manual manipulation of experimental conditions is required to address this task. In my thesis, I have overcome the above-mentioned challenges and developed an experimental strategy that for the first time provided predictive control over segmented flows in a hands-off manner. A computer-controlled platform that consisted of a real-time image processing module within an integral controller, a silicon-based microreactor and automated fluid delivery technique was designed, implemented and validated. In a first part of my thesis I utilized this approach for the automated screening of physical mass transfer and solubility characteristics of carbon dioxide (CO2) in a physical solvent at a well-defined temperature and pressure and a throughput of 12 conditions per hour. Second, by applying the segmented flow approach to a recently discovered CO2 chemical absorbent, frustrated Lewis pairs (FLPs), I determined the thermodynamic characteristics of the CO2-FLP reaction. Finally, the segmented flow approach was employed for characterization and investigation of CO2-governed liquid-liquid phase separation process. The second part of my thesis utilized the segmented flow platform for the preparation and shape control of high quality colloidal nanomaterials (e.g., CdSe/CdS) via the automated control of residence times up to approximately 5 minutes. By introducing a novel oscillatory segmented flow concept, I was able to further extend the residence time limitation to 24 hours. A case study of a
Mass flow and its pulsation measurements in supersonic wing wake
Shmakov, A. S.; Shevchenko, A. M.; Yatskikh, A. A.; Yermolaev, Yu. G.
2016-10-01
The results of experimental study of the flow in the wing wake are presented. Experiments were carried out in supersonic wind tunnel T-325 of ITAM SB RAS. Rectangle half-wing with sharp edges with a chord length of 30 mm and semispan of 95 mm was used to generate vortex wake. Experimental data were obtained in the cross section located 6 chord length downstream of the trailing edge at Mach numbers of 2.5 and 4 and at wing angles of attack of 4 and 10 degrees. Constant temperature hot-wire anemometer was used to measure disturbances in supersonic flow. Hot-wire was made of a tungsten wire with a diameter of 10 μm and length of 1.5 mm. Shlieren flow visualization were performed. As a result, the position and size of the vortex core in the wake of a rectangular wing were determined. For the first time experimental data on the mass flow distribution and its pulsations in the supersonic longitudinal vortex were obtained.
Morphology and the Color-mass Diagram as Clues to Galaxy Evolution at z&approx1
Powell, Meredith C.; Urry, C. Megan; Cardamone, Carolin N.; Simmons, Brooke D.; Schawinski, Kevin; Young, Sydney; Kawakatsu, Mari
2017-01-01
We study the significance of mergers in the quenching of star formation in galaxies at z∼ 1 by examining their color–mass distributions for different morphology types. We perform two-dimensional light profile fits to GOODS iz images of ∼5000 galaxies and X-ray selected active galactic nucleus (AGN) hosts in the CANDELS/GOODS-north and south fields in the redshift range 0.7< z< 1.3. Distinguishing between bulge-dominated and disk-dominated morphologies, we find that disks and spheroids have distinct color–mass distributions, in agreement with studies at z∼ 0. The smooth distribution across colors for the disk galaxies corresponds to a slow exhaustion of gas, with no fast quenching event. Meanwhile, blue spheroids most likely come from major mergers of star-forming disk galaxies, and the dearth of spheroids at intermediate green colors is suggestive of rapid quenching. The distribution of moderate luminosity X-ray AGN hosts is even across colors, in contrast, and we find similar numbers and distributions among the two morphology types with no apparent dependence on Eddington ratio. The high fraction of bulge-dominated galaxies that host an AGN in the blue cloud and green valley is consistent with the scenario in which the AGN is triggered after a major merger, and the host galaxy then quickly evolves into the green valley. This suggests AGN feedback may play a role in the quenching of star formation in the minority of galaxies that undergo major mergers.
Numerical modeling to investigate slopes and mass flow phenomena
Institute of Scientific and Technical Information of China (English)
Heinz Konietzky; Lei NIE; Youhong SUN
2006-01-01
An overview is given about up-to-date techniques for slope stability and deformation analysis as well as mass flow phenomena simulation. The paper concentrates on a few aspects in respect to the use of numerical modeling techniques, especially in relation to the shear strength reduction techniques, discontinuum modeling, probabilistic concepts, the combination of GIS and numerical modeling as well as sophisticated hydro-mechanical coupling with time-dependent material behavior. At present these topics are preferred topics of scientific and technical research.
Topology optimization of mass distribution problems in Stokes flow
DEFF Research Database (Denmark)
Gersborg-Hansen, Allan; Berggren, Martin; Dammann, Bernd
We consider topology optimization of mass distribution problems in 2D and 3D Stokes flow with the aim of designing devices that meet target outflow rates. For the purpose of validation, the designs have been post processed using the image processing tools available in FEMLAB. In turn, this has...... enabled an evaluation of the design with a body fitted mesh in a standard analysis software relevant in engineering practice prior to design manufacturing. This work investigates the proper choice of a maximum penalization value during the optimization process that ensures that the target outflow rates...
Coriolis mass-flow meter with integrated multi-DOF active vibration isolation
Ridder, A.; Hakvoort, W.B.J.; Brouwer, D.M.; Dijk, van J.; Lotters, J.C.; Boer, de A.
2016-01-01
Vibration isolation of more than 40 dB is achieved for a Coriolis Mass-Flow Meter (CMFM) with integrated Active Vibration Isolation. A CMFM is an active device based on the Coriolis force principle for direct mass-flow measurements independent of fluid properties. The mass-flow measurement is derive
Coriolis mass-flow meter with integrated multi-DOF active vibration isolation
van de Ridder, Bert; Hakvoort, Wouter; Brouwer, Dannis Michel; van Dijk, Johannes; Lötters, Joost Conrad; Lotters, Joost Conrad; de Boer, Andries
2016-01-01
Vibration isolation of more than 40 dB is achieved for a Coriolis Mass-Flow Meter (CMFM) with integrated Active Vibration Isolation. A CMFM is an active device based on the Coriolis force principle for direct mass-flow measurements independent of fluid properties. The mass-flow measurement is
The effect of flow and mass transport in thrombogenesis.
Basmadjian, D
1990-01-01
The paper presents a mathematical analysis of the contributions of flow and mass transport to a single reactive event at a blood vessel wall. The intent is to prepare the ground for a comprehensive study of the intertwining of these contributions with the reaction network of the coagulation cascade. We show that in all vessels with local mural activity, or in "large" vessels (d greater than 0.1 mm) with global reactivity, events at the tubular wall can be rigorously described by algebraic equations under steady conditions, or by ordinary differential forms (ODEs) during transient conditions. This opens up important ways for analyzing the combined roles of flow, transport, and coagulation reactions in thrombosis, a task hitherto considered to be completely intractable. We report extensively on the dependence of transport coefficient kL and mural coagulant concentration Cw on flow, vessel geometry, and reaction kinetics. It is shown that for protein transport, kL varies only weakly with shear rate gamma in large vessels, and not at all in the smaller tubes (d less than 10(-2) mm). For a typical protein, kL approximately 10(-3) cm s-1 within a factor of 3 in most geometries, irrespective of the mural reaction kinetics. Significant reductions in kL (1/10-1/1,000) leading to high-coagulant accumulation are seen mainly in stagnant zones vicinal to abrupt expansions and in small elliptical tubules. This is in accord with known physical observations. More unexpected are the dramatic increases in accumulation which can come about through the intervention of an autocatalytic reaction step, with Cw rising sharply toward infinity as the ratio of reaction to transport coefficient approaches unity. Such self-catalyzed reactions have the ability to act as powerful amplifiers of an otherwise modest influence of flow and transport on coagulant concentration. The paper considers as well the effect on mass transport of transient conditions occasioned by coagulation initiation or
Flow and mass transfer downstream of an orifice under flow accelerated corrosion conditions
Energy Technology Data Exchange (ETDEWEB)
Ahmed, Wael H., E-mail: ahmedw@kfupm.edu.sa [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals (KFUPM), P.O. Box 874, Dhahran 31261 (Saudi Arabia); Bello, Mufatiu M.; El Nakla, Meamer; Al Sarkhi, Abdelsalam [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals (KFUPM), P.O. Box 874, Dhahran 31261 (Saudi Arabia)
2012-11-15
Highlights: Black-Right-Pointing-Pointer Mass transfer downstream of orifices was numerically and experimentally investigated. Black-Right-Pointing-Pointer The surface wear pattern is measured and used to validate the present numerical results. Black-Right-Pointing-Pointer The maximum mass transfer coefficient found to occur at approximately 2-3 pipe diameters downstream of the orifice. Black-Right-Pointing-Pointer The FAC wear rates were correlated with the turbulence kinetic energy and wall mass transfer in terms of Sherwood number. Black-Right-Pointing-Pointer The current study offered very useful information for FAC engineers for better preparation of nuclear plant inspection scope. - Abstract: Local flow parameters play an important role in characterizing flow accelerated corrosion (FAC) downstream of sudden area change in power plant piping systems. Accurate prediction of the highest FAC wear rate locations enables the mitigation of sudden and catastrophic failures, and the improvement of the plant capacity factor. The objective of the present study is to evaluate the effect of the local flow and mass transfer parameters on flow accelerated corrosion downstream of an orifice. In the present study, orifice to pipe diameter ratios of 0.25, 0.5 and 0.74 were investigated numerically by solving the continuity and momentum equations at Reynolds number of Re = 20,000. Laboratory experiments, using test sections made of hydrocal (CaSO{sub 4}{center_dot} Vulgar-Fraction-One-Half H{sub 2}O) were carried out in order to determine the surface wear pattern and validate the present numerical results. The numerical results were compared to the plants data as well as to the present experiments. The maximum mass transfer coefficient found to occur at approximately 2-3 pipe diameters downstream of the orifice. This location was also found to correspond to the location of elevated turbulent kinetic energy generated within the flow separation vortices downstream of the orifice
Storey, Andrew P.; Zeiri, Offer M.; Ray, Steven J.; Hieftje, Gary M.
2017-02-01
The flowing atmospheric-pressure afterglow (FAPA) source was used for the mass-spectrometric analysis of vapor samples introduced between the source and mass spectrometer inlet. Through interrupted operation of the plasma-supporting helium flow, helium consumption is greatly reduced and dynamic gas behavior occurs that was characterized by schlieren imaging. Moreover, mass spectra acquired immediately after the onset of helium flow exhibit a signal spike before declining and ultimately reaching a steady level. This initial signal appears to be due to greater interaction of sample vapor with the afterglow of the source when helium flow resumes. In part, the initial spike in signal can be attributed to a pooling of analyte vapor in the absence of helium flow from the source. Time-resolved schlieren imaging of the helium flow during on and off cycles provided insight into gas-flow patterns between the FAPA source and the MS inlet that were correlated with mass-spectral data.
From State Diagram to Class Diagram
DEFF Research Database (Denmark)
Borch, Ole; Madsen, Per Printz
2009-01-01
UML class diagram and Java source code are interrelated and Java code is a kind of interchange format. Working with UML state diagram in CASE tools, a corresponding xml file is maintained. Designing state diagrams is mostly performed manually using design patterns and coding templates - a time...
Taylor, Edward N; van Dokkum, Pieter G; Bell, Eric F; Brammer, Gabriel B; Rudnick, Gregory; Wuyts, Stijn; Gawiser, Eric; Lira, Paulina; Urry, C Megan; Rix, Hans-Walter
2008-01-01
We present the color-magnitude and color-stellar mass diagrams for galaxies with z_phot 10^11 M_Sol galaxies in the range 0.2 10^11 M_Sol galaxies for z_phot ~1.3, however, we are no longer able to reliably distinguish red and blue subpopulations from the observed color distribution; we show that this would require much deeper near infrared data. At 1.5 10^11 M_Sol galaxies is ~50% of the local value, with a red fraction of ~33%. Making a parametric fit to the observed evolution, we find n_tot(z) ~ (1+z_phot)^(-0.52+/-0.12(+/-0.20)). We find stronger evolution in the red fraction: f_red(z) ~ (1+z_phot)^(-1.17+/-0.18(+/-0.21)). Through a series of sensitivity analyses, we show that the most important sources of systematic error are: 1. systematic differences in the analysis of the z~0 and z>>0 samples; 2. systematic effects associated with details of the photometric redshift calculation; and 3. uncertainties in the pho tometric calibration. With this in mind, we show that our results based on photometric r...
Flarakos, Jimmy; Liberman, Rosa G; Tannenbaum, Steven R; Skipper, Paul L
2008-07-01
Physical combination of an accelerator mass spectrometry (AMS) instrument with a conventional gas chromatograph-mass spectrometer (GC/MS) is described. The resulting hybrid instrument (GC/MS/AMS) was used to monitor mass chromatograms and radiochromatograms simultaneously when (14)C-labeled compounds were injected into the gas chromatograph. Combination of the two instruments was achieved by splitting the column effluent and directing half to the mass spectrometer and half to a flow-through CuO reactor in line with the gas-accepting AMS ion source. The reactor converts compounds in the GC effluent to CO2 as required for function of the ion source. With cholesterol as test compound, the limits of quantitation were 175 pg and 0.00175 dpm injected. The accuracy achieved in analysis of five nonzero calibration standards and three quality control standards, using cholesterol-2,2,3,4,4,6-d6 as injection standard, was 100 +/- 11.8% with selected ion monitoring and 100 +/- 16% for radiochromatography. Respective values for interday precision were 1.0-3.2 and 22-32%. Application of GC/MS/AMS to a current topic of interest was demonstrated in a model metabolomic study in which cultured primary hepatocytes were given [(14)C]glucose and organic acids excreted into the culture medium were analyzed.
Impact parameter dependence of collective flow and its disappearance for different mass asymmetries
Goyal, Supriya
2011-01-01
We study the role of impact parameter on the collective flow and its disappearance for different mass asymmetric reactions. The mass asymmetry is varied from 0 to 0.7 keeping the total mass of the system fixed. Our results clearly indicate a significant role of impact parameter on the collective flow and its disappearance for the mass asymmetric reactions. The impact parameter dependence is also found to vary with mass asymmetry of the reaction.
14 CFR 23.1443 - Minimum mass flow of supplemental oxygen.
2010-01-01
... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Minimum mass flow of supplemental oxygen... Equipment Miscellaneous Equipment § 23.1443 Minimum mass flow of supplemental oxygen. (a) If continuous flow oxygen equipment is installed, an applicant must show compliance with the requirements of...
GHRS observations of mass-loaded flows in Abell 78
Harrington, J. Patrick; Borkowski, Kazimierz J.; Tsvetanov, Zlatan
1995-01-01
Spectroscopic observations of the central star of the planetary nebula Abell 78 were obtained with the Goddard High Resolution Spectrograph (GHRS) onboard the Hubble Space Telescope (HST) in the vicinity of the C IV lambda 1548.2, 1550.8 doublet. We find a series of narrow absorption features superposed on the broad, P Cygni stellar wind profile. These features are seen in both components of the doublet at heliocentric radial velocities of -18, -71, -131, and -192 km/s. At higher velocities, individual components are no longer distinct but, rather, merge into a continuous absorption extending to approximately -385 km/s. This is among the highest velocities ever detected for gas in a planetary nebula. The -18 km/s feature originates in an outer envelope of normal composition, while the -71 km/s feature is produced in the wind-swept shell encircling an irregular wind-blown bubble in the planetary nebula center. The hydrogen-poor ejecta of Abell 78, consisting of dense knots with wind-blown tails, are located in the bubble's interior, in the vicinity of the stellar wind termination shock. The high-velocity C IV lambda 154 absorption features can be explained as due to parcels of ejecta being accelerated to high velocities as they are swept up by the stellar wind during its interaction with dense condensations of H-poor ejecta. As the ablated material is accelerated, it will partially mix with the stellar wind, creating a mass-loaded flow. The abundance anomalies seen at the rim of the bubble attest to the transport of H-poor knot material by such a flow.
Design and construction of a novel Coriolis mass flow rate meter
Mehendale, Aditya; Zwikker, Rini; Jouwsma, Wybren
2009-01-01
The Coriolis principle for measuring flow rates has great advantages compared to other flow measurement principles, the most important being that mass flow is measured directly. Up to now the measurement of low flow rates posed a great challenge. In a joint research project, the University of Twente
Design and construction of a novel Coriolis mass flow rate meter
Mehendale, A.; Zwikker, Rini; Jouwsma, Wybren
2009-01-01
The Coriolis principle for measuring flow rates has great advantages compared to other flow measurement principles, the most important being that mass flow is measured directly. Up to now the measurement of low flow rates posed a great challenge. In a joint research project, the University of Twente
Response timescales for martian ice masses and implications for ice flow on Mars
DEFF Research Database (Denmark)
Koutnik, Michelle Rebecca; Waddington, E.D.; Winebrener, D.P.;
2013-01-01
ice-flow rates were more significant than today. A plausible range of near-basal ice temperatures and ice-flow enhancement factors can generate the characteristic geometry of an ice mass that has been shaped by flow over reasonable volume-response timescales. All plausible ice-flow scenarios require...
Institute of Scientific and Technical Information of China (English)
李洪伟; 周云龙; 刘旭; 孙斌
2012-01-01
The characteristics of stability diagram of several typical flow patterns are studied,and the signals of flow patterns under 47 kinds of flowing conditions are identified with stochastic subspace parameter identification.The results show that the characteristic of a stability diagram can reflect the internal characteristics of complex time series,the characteristics of time series can be quantified by extracted straightness characteristics and the differences of characteristics of stability diagrams of three typical flow patterns.The characteristics of stability diagrams of bubble flow are the most confused and followed by Mist flows＇.Slug flows＇ are the most regular.The extraction and recognition for characteristics of gray fluctuation sequence of gas-liquid two-phase images and the accurate classification for flow pattern samples provide a new path for the classification of multi-phase flow patterns.At the same time,the stability diagram analysis method provides a useful exploration for the further revelation of flowing mechanism of multi-phase flows.%研究了儿种典型气液两相干流流型的稳定图特征,并应用随机子空间方法对47种流动条件下的流型信号进行了识别.研究结果表明：稳定图特征能够反映出复杂时间序列的内部特征,利用其提取的直线度特征值可以对时间序列的特征进行量化分析,三种典型流型的稳定图特征差异较明显,泡状流的稳定图特征最为混乱.雾状流次之.段塞流量为规整.应用随机子空间方法对气液两相流图像灰度波动序列进行特征向量提取和辨识,通过幅值以及相角的分布特征能够对不同工况下的流型样本进行准确分类,为多相流的分类提供了一条新路径.同时基于稳定图的分析方法为进一步揭示多相流的流动机理提供有益的探索.
Breviz: Visualizing Spreadsheets using Dataflow Diagrams
Hermans, Felienne; van Deursen, Arie
2011-01-01
Spreadsheets are used extensively in industry, often for business critical purposes. In previous work we have analyzed the information needs of spreadsheet professionals and addressed their need for support with the transition of a spreadsheet to a colleague with the generation of data flow diagrams. In this paper we describe the application of these data flow diagrams for the purpose of understanding a spreadsheet with three example cases. We furthermore suggest an additional application of the data flow diagrams: the assessment of the quality of the spreadsheet's design.
Directory of Open Access Journals (Sweden)
Yu. M. Timofeev
2016-01-01
Full Text Available The turbulent-flow throttles are used in pneumatic systems and gas-supply ones to restrict or measure gas mass flow. It is customary to install the throttles in joints of pipelines (in teejoints and cross tees or in joints of pipelines with pneumatic automation devices Presently, in designing the pneumatic systems and gas-supply ones a gas mass flow through a throttle is calculated by a known equation derived from the Saint-Venant-Vantсel formula for the adiabatic flow of ideal gas through a nozzle from an unrestrictedly high capacity tank. Neglect of gas velocity at the throttle inlet is one of the assumptions taken in the development of the above equation. As may be seen in practice, in actual systems the diameters of the throttle and the pipe wherein it is mounted can be commensurable. Neglect of the inlet velocity therewith can result in an error when determining the required throttle diameter in design calculation and a flow rate in checking calculation, as well as when measuring a flow rate in the course of the test. The theoretical study has revealed that the flow velocity at the throttle inlet is responsible for two parameter values: the outlet flow velocity and the critical pressure ratio, which in turn determine the gas mass flow value. To calculate the gas mass flow, the dependencies are given in the paper, which allow taking into account the flow rate at the throttle inlet. The analysis of obtained dependencies has revealed that the degree of influence of inlet flow rate upon the mass flow is defined by two parameters: pressure ratio at the throttle and open area ratio of the throttle and the pipe wherein it is mounted. An analytical investigation has been pursued to evaluate the extent to which the gas mass flow through the throttle is affected by the inlet flow rate. The findings of the investigation and the indications for using the present dependencies are given in this paper. By and large the investigation allowed the
Directory of Open Access Journals (Sweden)
Pengmin Pan
2016-12-01
Full Text Available An 8-electrode capacitance tomography (ECT sensor was built and used to measure moisture content (MC and mass flow of pine chip flows. The device was capable of directly measuring total water quantity in a sample but was sensitive to both dry matter and moisture, and therefore required a second measurement of mass flow to calculate MC. Two means of calculating the mass flow were used: the first being an impact sensor to measure total mass flow, and the second a volumetric approach based on measuring total area occupied by wood in images generated using the capacitance sensor’s tomographic mode. Tests were made on 109 groups of wood chips ranging in moisture content from 14% to 120% (dry basis and wet weight of 280 to 1100 g. Sixty groups were randomly selected as a calibration set, and the remaining were used for validation of the sensor’s performance. For the combined capacitance/force transducer system, root mean square errors of prediction (RMSEP for wet mass flow and moisture content were 13.42% and 16.61%, respectively. RMSEP using the combined volumetric mass flow/capacitance sensor for dry mass flow and moisture content were 22.89% and 24.16%, respectively. Either of the approaches was concluded to be feasible for prediction of moisture content in pine chip flows, but combining the impact and capacitance sensors was easier to implement. In situations where flows could not be impeded, however, the tomographic approach would likely be more useful.
The spectroscopic Hertzsprung-Russell diagram
Langer, N
2014-01-01
The Hertzsprung-Russell diagram is an essential diagnostic diagram for stellar structure and evolution, which has now been in use for more than 100 years. Our spectroscopic Hertzsprung-Russell (sHR) diagram shows the inverse of the flux-mean gravity versus the effective temperature. Observed stars whose spectra have been quantitatively analyzed can be entered in this diagram without the knowledge of the stellar distance or absolute brightness. Observed stars can be as conveniently compared to stellar evolution calculations in the sHR diagram as in the Hertzsprung-Russell diagram. However, at the same time, our ordinate is proportional to the stellar mass-to-luminosity ratio, which can thus be directly determined. For intermediate- and low-mass star evolution at constant mass, we show that the shape of an evolutionary track in the sHR diagram is identical to that in the Hertzsprung-Russell diagram. We also demonstrate that for hot stars, their stellar Eddington factor can be directly read off the sHR diagram. ...
Automatic fitting procedure for the fundamental diagram
Knoop, V.L.; Daamen, W.
2014-01-01
The fundamental diagram of a road, including free flow capacity and queue discharge rate, is very important for traffic engineering purposes. In the real word, most traffic measurements come from stationary loop detectors. This paper proposes a method to fit Wu’s fundamental diagram to loop detector
A new index for precise design and advanced operation of mass transfer in slug flow
Aoki, Nobuaki; Tanigawa, Shin; Mae, Kazuhiro
2011-01-01
Slug flow, one of the ordered multi-phase flow patterns in a small channel, has the advantage of the enhancement of mixing in each phase and mass transfer between two phases due to the internal circulation flow. To form stable slug flow, the throughput of order of μL min−1 has been employed. To use slug flow in industrial scale, however, controlled and high throughput mass transfer and an index for design of a channel with slug flow are required. To address this requirement, we examined the i...
Institute of Scientific and Technical Information of China (English)
曹新平
2013-01-01
Objective To explore an infection control method for open trauma surgery using fishbone diagram and flow chart. Methods A fishbone diagram and a flow chart were drawn to identify the factors contributing to infection after open trauma surgery. Then 8 operating room nurses were were trained to use the fishbone diagram and the flow chart before the diagram and the chart were put into clinical practice. Results Before and after application of the fishbone diagram and the flow chart, nurses test scores in factors contributing to infection after open trauma surgery and infection control knowledge, rates of occupational exposures had significant differences(P＜0. 01,P＜0. 05) . The rate of accurate coping with an occupational exposure increased from 67. 31% to 100%. Conclusion Fishbone diagrams and flow charts which indentify the factors contributing to infection after open trauma surgery could effectively help nurses enhance the infection control quality of open trauma surgery, and decrease the incidence of occupational exposure.%目的 探讨鱼骨图和流程图在开放性创伤手术感染管理中的应用方法与效果.方法 制定开放性创伤手术感染因素鱼骨图和感染管理流程图,首先对手术室8名护士进行培训,然后将该图用于开放性创伤手术配合和管理中.结果 应用鱼骨图和流程图前后,护士开放性创伤手术易感因素和感染管理知识考核成绩、职业暴露率比较,差异有统计学意义(P＜0.01,P＜0.05);发生职业暴露后正确处理率由67.31%上升至100%.结论 应用开放性创伤手术感染因素鱼骨图和感染管理流程图,可以帮助护士有效提高开放性创伤手术的感染管理质量,降低职业暴露发生率.
Influence of Reduced Mass Flow Rate and Chamber Backpressure on Swirl Injector Fluid Mechanics
Kenny, R Jeremy; Hulka, James R.
2008-01-01
Industry interest in variable-thrust liquid rocket engines places a demand on engine injector technology to operate over a wide range of liquid mass flow rates and chamber backpressures. One injection technology of current interest for variable thrust applications is an injector design with swirled fluids. Current swirl injector design methodologies do not take into account how swirl injector design parameters respond to elevated chamber backpressures at less than design mass flow rates. The current work was created to improve state-of-the-art swirl injector design methods in this area. The specific objective was to study the effects of elevated chamber backpressure and off-design mass flow rates on swirl injector fluid mechanics. Using a backpressure chamber with optical access, water was flowed through a swirl injector at various combinations of chamber backpressure and mass flow rates. The film thickness profile down the swirl injector nozzle section was measured through a transparent nozzle section of the injector. High speed video showed measurable increases in the film thickness profile with application of chamber backpressure and mass flow rates less than design. At prescribed combinations of chamber backpressure and injected mass flow rate, a discrete change in the film thickness profile was observed. Measured injector discharge coefficient values showed different trends with increasing chamber backpressure at low mass flow rates as opposed to near-design mass flow rates. Downstream spray angles showed classic changes in morphology as the mass flow rate was decreased below the design value. Increasing chamber backpressure decreased the spray angle at any injection mass flow rate. Experimental measurements and discussion of these results are reported in this paper.
Influence of Reduced Mass Flow Rate and Chamber Backpressure on Swirl Injector Fluid Mechanics
Kenny, R Jeremy; Hulka, James R.
2008-01-01
Industry interest in variable-thrust liquid rocket engines places a demand on engine injector technology to operate over a wide range of liquid mass flow rates and chamber backpressures. One injection technology of current interest for variable thrust applications is an injector design with swirled fluids. Current swirl injector design methodologies do not take into account how swirl injector design parameters respond to elevated chamber backpressures at less than design mass flow rates. The current work was created to improve state-of-the-art swirl injector design methods in this area. The specific objective was to study the effects of elevated chamber backpressure and off-design mass flow rates on swirl injector fluid mechanics. Using a backpressure chamber with optical access, water was flowed through a swirl injector at various combinations of chamber backpressure and mass flow rates. The film thickness profile down the swirl injector nozzle section was measured through a transparent nozzle section of the injector. High speed video showed measurable increases in the film thickness profile with application of chamber backpressure and mass flow rates less than design. At prescribed combinations of chamber backpressure and injected mass flow rate, a discrete change in the film thickness profile was observed. Measured injector discharge coefficient values showed different trends with increasing chamber backpressure at low mass flow rates as opposed to near-design mass flow rates. Downstream spray angles showed classic changes in morphology as the mass flow rate was decreased below the design value. Increasing chamber backpressure decreased the spray angle at any injection mass flow rate. Experimental measurements and discussion of these results are reported in this paper.
Alveringh, Dennis; Groenesteijn, Jarno; Ma, Kechun; Wiegerink, Remco J.; Lötters, Joost Conrad
2015-01-01
We report on a novel capacitive detection principle for Coriolis mass flow sensors which allows for one order of magnitude increased sensitivity. The detection principle consists of two pairs of comb-structures: one pair produces two signals with a phase shift directly dependent on the mass flow,
Evaluation of an experimental mass-flow sensor of cotton-lint at the gin
As part of a system to optimize the cotton ginning process, a custom built mass-flow sensor was evaluated at USDA-ARS Cotton Ginning Research Unit at Stoneville, Mississippi. The mass-flow sensor was fabricated based on the principle of the senor patented by Thomasson and Sui (2004). The optical a...
Herzog, Franz; Ueda, Takahiro; Vermaseren, J A M; Vogt, Andreas
2016-01-01
We discuss a number of FORM features that are essential in the automatic processing of very large numbers of diagrams as used in the Forcer program for 4-loop massless propagator diagrams. Most of these features are new.
Zheng, Qiong; Xing, Feng; Li, Xianfeng; Ning, Guiling; Zhang, Huamin
2016-08-01
Vanadium flow battery holds great promise for use in large scale energy storage applications. However, the power density is relatively low, leading to significant increase in the system cost. Apart from the kinetic and electronic conductivity improvement, the mass transport enhancement is also necessary to further increase the power density and reduce the system cost. To better understand the mass transport limitations, in the research, the space-varying and time-varying characteristic of the mass transport polarization is investigated based on the analysis of the flow velocity and reactant concentration in the bulk electrolyte by modeling. The result demonstrates that the varying characteristic of mass transport polarization is more obvious at high SoC or high current densities. To soften the adverse impact of the mass transport polarization, a new rectangular plug flow battery with a plug flow and short flow path is designed and optimized based on the mass transport polarization regulation (reducing the mass transport polarization and improving its uniformity of distribution). The regulation strategy of mass transport polarization is practical for the performance improvement in VFBs, especially for high power density VFBs. The findings in the research are also applicable for other flow batteries and instructive for practical use.
Mass transfer from a sphere in an oscillating flow with zero mean velocity
Drummond, Colin K.; Lyman, Frederic A.
1990-01-01
A pseudospectral numerical method is used for the solution of the Navier-Stokes and mass transport equations for a sphere in a sinusoidally oscillating flow with zero mean velocity. The flow is assumed laminar and axisymmetric about the sphere's polar axis. Oscillating flow results were obtained for Reynolds numbers (based on the free-stream oscillatory flow amplitude) between 1 and 150, and Strouhal numbers between 1 and 1000. Sherwood numbers were computed and their dependency on the flow frequency and amplitude discussed. An assessment of the validity of the quasi-steady assumption for mass transfer is based on these results.
Real time mass flow rate measurement using multiple fan beam optical tomography.
Abdul Rahim, R; Leong, L C; Chan, K S; Rahiman, M H; Pang, J F
2008-01-01
This paper presents the implementing multiple fan beam projection technique using optical fibre sensors for a tomography system. From the dynamic experiment of solid/gas flow using plastic beads in a gravity flow rig, the designed optical fibre sensors are reliable in measuring the mass flow rate below 40% of flow. Another important matter that has been discussed is the image processing rate or IPR. Generally, the applied image reconstruction algorithms, the construction of the sensor and also the designed software are considered to be reliable and suitable to perform real-time image reconstruction and mass flow rate measurements.
Extrinsic Curvature Embedding Diagrams
Lu, J L
2003-01-01
Embedding diagrams have been used extensively to visualize the properties of curved space in Relativity. We introduce a new kind of embedding diagram based on the {\\it extrinsic} curvature (instead of the intrinsic curvature). Such an extrinsic curvature embedding diagram, when used together with the usual kind of intrinsic curvature embedding diagram, carries the information of how a surface is {\\it embedded} in the higher dimensional curved space. Simple examples are given to illustrate the idea.
Energy Technology Data Exchange (ETDEWEB)
Kim, Woohyun; Braun, J.
2016-03-05
Refrigerant mass flow rate is an important measurement for monitoring equipment performance and enabling fault detection and diagnostics. However, a traditional mass flow meter is expensive to purchase and install. A virtual refrigerant mass flow sensor (VRMF) uses a mathematical model to estimate flow rate using low-cost measurements and can potentially be implemented at low cost. This study evaluates three VRMFs for estimating refrigerant mass flow rate. The first model uses a compressor map that relates refrigerant flow rate to measurements of inlet and outlet pressure, and inlet temperature measurements. The second model uses an energy-balance method on the compressor that uses a compressor map for power consumption, which is relatively independent of compressor faults that influence mass flow rate. The third model is developed using an empirical correlation for an electronic expansion valve (EEV) based on an orifice equation. The three VRMFs are shown to work well in estimating refrigerant mass flow rate for various systems under fault-free conditions with less than 5% RMS error. Each of the three mass flow rate estimates can be utilized to diagnose and track the following faults: 1) loss of compressor performance, 2) fouled condenser or evaporator filter, 3) faulty expansion device, respectively. For example, a compressor refrigerant flow map model only provides an accurate estimation when the compressor operates normally. When a compressor is not delivering the expected flow due to a leaky suction or discharge valve or other internal fault, the energy-balance or EEV model can provide accurate flow estimates. In this paper, the flow differences provide an indication of loss of compressor performance and can be used for fault detection and diagnostics.
A Smart Thermal Block Diagram Tool
Tsuyuki, Glenn; Miyake, Robert; Dodge, Kyle
2008-01-01
The presentation describes a Smart Thermal Block Diagram Tool. It is used by JPL's Team X in studying missions during the Pre-Phase A. It helps generate cost and mass estimates using proprietary data bases.
Pedone, Richard; Korman, Valentin; Wiley, John T.
2006-05-01
Accurate and reliable multiphase flow measurements are needed for liquid propulsion systems. Existing volumetric flow meters are adequate for flow measurements with well-characterized, clean liquids and gases. However, these technologies are inadequate for multiphase environments, such as cryogenic fluids. Although, properly calibrated turbine flow meters can provide highly accurate and repeatable data, problems are still prevalent with multiphase flows. Limitations are thus placed on the applicability of intrusive turbine flow meters.
Impact of Organic-Liquid Distribution and Flow-Field Heterogeneity on Reductions in Mass Flux
Energy Technology Data Exchange (ETDEWEB)
Difilippo, Erica L.; Carroll, Kenneth C.; Brusseau, Mark L.
2010-06-07
A series of flow-cell experiments was conducted to investigate the impact of organic-liquid distribution and flow-field heterogeneity on the relationship between source-zone mass removal and reductions in contaminant mass flux from the source zone. Changes in source-zone architecture were quantified using image analysis, allowing explicit examination of their impact on the mass-flux-reduction/mass-removal behavior. The results showed that there was minimal reduction in mass flux until a large fraction of mass was removed for systems wherein organic liquid was present solely as residual saturation in regions that were hydraulically accessible. Conversely, significant reductions in mass flux occurred with relatively minimal mass removal for systems wherein organic liquid was present at both residual and higher saturations. The latter systems exhibited multi-step mass-flux-reduction/mass-removal behavior, and characterization of the organic-liquid saturation distribution throughout flushing allowed identification of the cause of the nonideal behavior. The age of the source zone (time from initial emplacement to time of initial characterization) significantly influenced the observed mass-flux-reduction/mass-removal behavior. The results of this study illustrate the impact of both organic-liquid distribution and flow-field heterogeneity on mass-removal and mass-flux processes.
Phase Equilibria Diagrams Database
SRD 31 NIST/ACerS Phase Equilibria Diagrams Database (PC database for purchase) The Phase Equilibria Diagrams Database contains commentaries and more than 21,000 diagrams for non-organic systems, including those published in all 21 hard-copy volumes produced as part of the ACerS-NIST Phase Equilibria Diagrams Program (formerly titled Phase Diagrams for Ceramists): Volumes I through XIV (blue books); Annuals 91, 92, 93; High Tc Superconductors I & II; Zirconium & Zirconia Systems; and Electronic Ceramics I. Materials covered include oxides as well as non-oxide systems such as chalcogenides and pnictides, phosphates, salt systems, and mixed systems of these classes.
DEFF Research Database (Denmark)
Duijm, Nijs Jan
2007-01-01
are discussed. A simple method for quantification of safety-barrier diagrams is proposed, including situations where safety barriers depend on shared common elements. It is concluded that safety-barrier diagrams provide a useful framework for an electronic data structure that integrates information from risk......Safety-barrier diagrams and the related so-called "bow-tie" diagrams have become popular methods in risk analysis. This paper describes the syntax and principles for constructing consistent and valid safety-barrier diagrams. The relation with other methods such as fault trees and Bayesian networks...... analysis with operational safety management....
Mass transfer coefficients in cross-flow ultrafiltration
Berg, van den G.B.; Rácz, I.G.; Smolders, C.A.
1989-01-01
Usually, in concentration polarization models, the mass transfer coefficient is an unknown parameter. Also, its variation with changing experimental circumstances is in question. In the literature, many relationships can be found to describe the mass transfer coefficient under various conditions, as
Mass transfer coefficients in cross-flow ultrafiltration
van den Berg, G.B.; Racz, I.G.; Smolders, C.A.
1989-01-01
Usually, in concentration polarization models, the mass transfer coefficient is an unknown parameter. Also, its variation with changing experimental circumstances is in question. In the literature, many relationships can be found to describe the mass transfer coefficient under various conditions, as
Directory of Open Access Journals (Sweden)
M. B. Akgül
2012-01-01
Full Text Available Hydromagnetic flow and mass transfer of a viscous incompressible fluid over a microcantilever sensor surface are studied in the presence of slip flow. In addition, chemical reaction at the sensor surface is taken into account. The governing equations for the flow are reduced to a local nonsimilarity form. Resulting equations are solved numerically for various values of flow parameters. Effects of physical quantities on the velocity and concentration profiles are discussed in detail.
Energy Technology Data Exchange (ETDEWEB)
Jing, J.P.; Li, Z.Q.; Wang, L.; Chen, Z.C.; Chen, L.Z.; Zhang, F.C. [Harbin Institute of Technology, Harbin (China)
2011-06-15
The influence of the mass flow rate of secondary air on the gas/particle flow characteristics of a double swirl flow burner, in the near-burner region, was measured by a three-component particle-dynamics anemometer, in conjunction with a gas/particle two-phase test facility. Velocities, particle volume flux profiles, and normalized particle number concentrations were obtained. The relationship between the gas/particle flows and the combustion characteristics of the burners was discussed. For different mass flow rates of secondary air, annular recirculation zones formed only in the region of r/d=0.3-0.6 at x/d=0.1-0.3. With an increasing mass flow rate of secondary air, the peaks of the root mean square (RMS) axial fluctuating velocities, radial mean velocities, RMS radial fluctuating velocities, and tangential velocities all increased, while the recirculation increased slightly. There was a low particle volume flux in the central zone of the burner. At x/d=0.1-0.7, the profiles of particle volume flux had two peaks in the secondary air flow zone near the wall. With an increasing mass flow rate of secondary air, the peak of particle volume flux in the secondary air flow zone decreased, but the peak of particle volume flux near the wall increased. In section x/d=0.1-0.5, the particle diameter in the central zone of the burner was always less than the particle diameter at other locations.
Renormalized entanglement entropy flow in mass-deformed ABJM theory
Kim, Kyung Kiu; Kwon, O.-Kab; Park, Chanyong; Shin, Hyeonjoon
2014-08-01
We investigate a mass deformation effect on the renormalized entanglement entropy (REE) near the UV fixed point in (2+1)-dimensional field theory. In the context of the gauge/gravity duality, we use the Lin-Lunin-Maldacena geometries corresponding to the vacua of the mass-deformed ABJM theory. We analytically compute the small mass effect for various droplet configurations and show in holographic point of view that the REE is monotonically decreasing, positive, and stationary at the UV fixed point. These properties of the REE in (2+1)-dimensions are consistent with the Zamolodchikov c-function proposed in (1+1)-dimensional conformal field theory.
Helium mass flow measurement in the International Fusion Superconducting Magnet Test Facility
Energy Technology Data Exchange (ETDEWEB)
Baylor, L.R.
1986-08-01
The measurement of helium mass flow in the International Fusion Superconducting Magnet Test Facility (IFSMTF) is an important aspect in the operation of the facility's cryogenic system. Data interpretation methods that lead to inaccurate results can cause severe difficulty in controlling the experimental superconducting coils being tested in the facility. This technical memorandum documents the methods of helium mass flow measurement used in the IFSMTF for all participants of the Large Coil Program and for other cryogenic experimentalists needing information on mass flow measurements. Examples of experimental data taken and calculations made are included to illustrate the applicability of the methods used.
Mukai, Masaaki; Kobayashi, Ryozo
These volumes are, respectively, the self-instructional student manual and the teacher manual that cover the first set of training topics in this course for television repair technicians. Both volumes contain the following two sections: (1) Functional Block Diagram of a Colour TV Receiver, including information on the video reproduction circuit,…
Flow-dependent mass transfer may trigger endothelial signaling cascades.
Vandrangi, Prashanthi; Sosa, Martha; Shyy, John Y-J; Rodgers, Victor G J
2012-01-01
It is well known that fluid mechanical forces directly impact endothelial signaling pathways. But while this general observation is clear, less apparent are the underlying mechanisms that initiate these critical signaling processes. This is because fluid mechanical forces can offer a direct mechanical input to possible mechanotransducers as well as alter critical mass transport characteristics (i.e., concentration gradients) of a host of chemical stimuli present in the blood stream. However, it has recently been accepted that mechanotransduction (direct mechanical force input), and not mass transfer, is the fundamental mechanism for many hemodynamic force-modulated endothelial signaling pathways and their downstream gene products. This conclusion has been largely based, indirectly, on accepted criteria that correlate signaling behavior and shear rate and shear stress, relative to changes in viscosity. However, in this work, we investigate the negative control for these criteria. Here we computationally and experimentally subject mass-transfer limited systems, independent of mechanotransduction, to the purported criteria. The results showed that the negative control (mass-transfer limited system) produced the same trends that have been used to identify mechanotransduction-dominant systems. Thus, the widely used viscosity-related shear stress and shear rate criteria are insufficient in determining mechanotransduction-dominant systems. Thus, research should continue to consider the importance of mass transfer in triggering signaling cascades.
The use of mass flow meters in the PER+ refinery; PER+ verlegt grenzen van massaflowmeters
Energy Technology Data Exchange (ETDEWEB)
Dijkgraaf, A. [ed.
1998-02-01
An adjusted Coriolis mass flowmeter for 365C and 100 bar is applied in the new Shell refinery PER+ in Rotterdam, Netherlands. The flowmeter can handle the flow of liquid asphalt of which the composition and density can vary strongly
Fiber Optic Mass Flow Gauge for Liquid Cryogenic Fuel Facilities Monitoring and Control Project
National Aeronautics and Space Administration — This SBIR Phase I proposal describes a fiber optic mass flow gauge that will aid in managing liquid hydrogen and oxygen fuel storage and transport. The increasing...
FEFLOW finite element modeling of flow, mass and heat transport in porous and fractured media
Diersch, Hans-Jörg G
2013-01-01
Placing advanced theoretical and numerical methods in the hands of modeling practitioners and scientists, this book explores the FEFLOW system for solving flow, mass and heat transport processes in porous and fractured media. Offers applications and exercises.
Integrated pressure sensing using capacitive Coriolis mass flow sensors
Alveringh, Dennis; Wiegerink, Remco J.; Lötters, Joost Conrad
2017-01-01
The cross-sectional shape of microchannels is, dependent on the fabrication method, never perfectly circular. Consequently, the channels deform with the pressure, which is a non-ideal effect in flow sensors, but may be used for pressure sensing. Multiple suspended channels with different lengths
Effect of Reynolds number on flow and mass transfer characteristics of a 90 degree elbow
Fujisawa, Nobuyuki; Ikarashi, Yuya; Yamagata, Takayuki; Taguchi, Syoichi
2016-11-01
The flow and mass transfer characteristics of a 90 degree elbow was studied experimentally by using the mass transfer measurement by plaster dissolution method, the surface flow visualization by oil film method and stereo PIV measurement. The experiments are carried out in a water tunnel of a circular pipe of 56mm in diameter with a working fluid of water. The Reynolds number was varied from 30000 to 200000. The experimental result indicated the change of the mass transfer coefficient distribution in the elbow with increasing the Reynolds number. This phenomenon is further examined by the surface flow visualization and measurement of secondary flow pattern in the elbow, and the results showed the suggested change of the secondary flow pattern in the elbow with increasing the Reynolds numbers.
Boundary Layer Flows in Porous Media with Lateral Mass Flux
DEFF Research Database (Denmark)
Nemati, H; H, Bararnia; Noori, F;
2015-01-01
Solutions for free convection boundary layers on a heated vertical plate with lateral mass flux embedded in a saturated porous medium are presented using the Homotopy Analysis Method and Shooting Numerical Method. Homotopy Analysis Method yields an analytic solution in the form of a rapidly...
Test of pressure transducer for measuring cotton-mass flow
In this study, a cotton harvester yield monitor was developed based on the relationship between air pressure and the mass of seed cotton conveyed. The sensor theory was verified by laboratory tests. The sensor was tested on a cotton picker with seed cotton at two moisture contents, 5.9% and 8.5% we...
Thin-Film Air-Mass-Flow Sensor of Improved Design Developed
Fralick, Gustave C.; Wrbanek, John D.; Hwang, Danny P.
2003-01-01
Researchers at the NASA Glenn Research Center have developed a new air-mass-flow sensor to solve the problems of existing mass flow sensor designs. NASA's design consists of thin-film resistors in a Wheatstone bridge arrangement. The resistors are fabricated on a thin, constant-thickness airfoil to minimize disturbance to the airflow being measured. The following photograph shows one of NASA s prototype sensors. In comparison to other air-mass-flow sensor designs, NASA s thin-film sensor is much more robust than hot wires, causes less airflow disturbance than pitot tubes, is more accurate than vane anemometers, and is much simpler to operate than thermocouple rakes. NASA s thin-film air-mass-flow sensor works by converting the temperature difference seen at each leg of the thin-film Wheatstone bridge into a mass-flow rate. The following figure shows a schematic of this sensor with air flowing around it. The sensor operates as follows: current is applied to the bridge, which increases its temperature. If there is no flow, all the arms are heated equally, the bridge remains in balance, and there is no signal. If there is flow, the air passing over the upstream legs of the bridge reduces the temperature of the upstream legs and that leads to reduced electrical resistance for those legs. After the air has picked up heat from the upstream legs, it continues and passes over the downstream legs of the bridge. The heated air raises the temperature of these legs, increasing their electrical resistance. The resistance difference between the upstream and downstream legs unbalances the bridge, causing a voltage difference that can be amplified and calibrated to the airflow rate. Separate sensors mounted on the airfoil measure the temperature of the airflow, which is used to complete the calculation for the mass of air passing by the sensor. A current application for air-mass-flow sensors is as part of the intake system for an internal combustion engine. A mass-flow sensor is
Institute of Scientific and Technical Information of China (English)
LI Shichun
2004-01-01
Based on the Thomas-Fermi-Dirac-Cheng model, atomic phase diagram or electron density versus atomic radius diagram describing the interaction properties of atoms of different kinds in equilibrium state is developed. Atomic phase diagram is established based on the two-atoms model. Besides atomic radius, electron density and continuity condition for electron density on interfaces between atoms, the lever law of atomic phase diagram involving other physical parameters is taken into account, such as the binding energy, for the sake of simplicity.
A net-jet flow system for mass transfer and microsensor studies of sinking aggregates
DEFF Research Database (Denmark)
Ploug, H.; Jørgensen, BB
1999-01-01
was shown to be laminar at flow velocities ranging from 40 to 200 m d(-1), which cover typical sinking velocities of aggregates in the ocean. A viscous boundary layer with steep gradients of flow velocity was measured around sinking aggregates by flow visualization techniques. Velocity gradients......A flow system was developed which enables studies of hydrodynamics and mass transfer in freely sinking aggregates. The aggregates stabilized their positions in the water phase at an upward flow Velocity which balanced and opposed the sinking velocity of the individual aggregate. The flow field...... in the viscous boundary layer along the sides of the aggregate parallel to the flow could by explained by creeping flow, while a non-turbulent wake was present at the rear (downstream) of the aggregate. The oxygen distribution inside a ca 3.5 mm large diatom aggregate and in the surrounding water was mapped in 2...
Modeling, design, fabrication and characterization of a micro Coriolis mass flow sensor
Haneveld, J.; Lammerink, T.S.J.; Boer, de M.J.; Sanders, R.G.P.; Mehendale, Aditya; Lotters, J.C.; Dijkstra, M.A.; Wiegerink, R.J.
2010-01-01
This paper discusses the modeling, design and realization of micromachined Coriolis mass flow sensors. A lumped element model is used to analyze and predict the sensor performance. The model is used to design a sensor for a flow range of 0–1.2 g h−1 with a maximum pressure drop of 1 bar. The sensor
An empirical method for estimating travel times for wet volcanic mass flows
Pierson, Thomas C.
1998-01-01
Travel times for wet volcanic mass flows (debris avalanches and lahars) can be forecast as a function of distance from source when the approximate flow rate (peak discharge near the source) can be estimated beforehand. The near-source flow rate is primarily a function of initial flow volume, which should be possible to estimate to an order of magnitude on the basis of geologic, geomorphic, and hydrologic factors at a particular volcano. Least-squares best fits to plots of flow-front travel time as a function of distance from source provide predictive second-degree polynomial equations with high coefficients of determination for four broad size classes of flow based on near-source flow rate: extremely large flows (>1 000 000 m3/s), very large flows (10 000–1 000 000 m3/s), large flows (1000–10 000 m3/s), and moderate flows (100–1000 m3/s). A strong nonlinear correlation that exists between initial total flow volume and flow rate for "instantaneously" generated debris flows can be used to estimate near-source flow rates in advance. Differences in geomorphic controlling factors among different flows in the data sets have relatively little effect on the strong nonlinear correlations between travel time and distance from source. Differences in flow type may be important, especially for extremely large flows, but this could not be evaluated here. At a given distance away from a volcano, travel times can vary by approximately an order of magnitude depending on flow rate. The method can provide emergency-management officials a means for estimating time windows for evacuation of communities located in hazard zones downstream from potentially hazardous volcanoes.
Active vibration isolation feedback control for Coriolis Mass-Flow Meters
Ridder, van de L.; Beijen, M.A.; Hakvoort, W.B.J.; Dijk, van J.; Lötters, J.C.; Boer, de A.
2014-01-01
Active Vibration Isolation Control (AVIC) can be used to reduce the transmissibility of external vibrations to internal vibrations. In this paper a proposal is made for integrating AVIC in a Coriolis Mass-Flow Meter (CMFM). Acceleration feedback, virtual mass and virtual skyhook damping are added to
Tarquini, Simone
2017-08-01
A simple formula relates lava discharge rate to the heat radiated per unit time from the surface of active lava flows (the "thermal proxy"). Although widely used, the physical basis of this proxy is still debated. In the present contribution, lava flows are approached as open, dissipative systems that, under favorable conditions, can attain a non-equilibrium stationary state. In this system framework, the onset, growth, and demise of lava flow units can be explained as a self-organization phenomenon characterized by a given temporal frequency defined by the average life span of active lava flow units. Here, I review empirical, physical, and experimental models designed to understand and link the flow of mass and energy through a lava flow system, as well as measurements and observations that support a "real-world" view. I set up two systems: active lava flow system (or ALFS) for flowing, fluid lava and a lava deposit system for solidified, cooling lava. The review highlights surprising similarities between lava flows and electric currents, which typically work under stationary conditions. An electric current propagates almost instantaneously through an existing circuit, following the Kirchhoff law (a least dissipation principle). Flowing lavas, in contrast, build up a slow-motion "lava circuit" over days, weeks, or months by following a gravity-driven path down the steepest slopes. Attainment of a steady-state condition is hampered (and the classic thermal proxy does not hold) if the supply stops before completion of the "lava circuit." Although gravity determines initial flow path and extension, the least dissipation principle means that subsequent evolution of mature portions of the active lava flow system is controlled by increasingly insulated conditions.
DEFF Research Database (Denmark)
Celia, Michael A.; Binning, Philip John
1992-01-01
. Numerical results also demonstrate the potential importance of air phase advection when considering contaminant transport in unsaturated soils. Comparison to several other numerical algorithms shows that the modified Picard approach offers robust, mass conservative solutions to the general equations......A numerical algorithm for simulation of two-phase flow in porous media is presented. The algorithm is based on a modified Picard linearization of the governing equations of flow, coupled with a lumped finite element approximation in space and dynamic time step control. Numerical results indicate...... that the algorithm produces solutions that are essentially mass conservative and oscillation free, even in the presence of steep infiltrating fronts. When the algorithm is applied to the case of air and water flow in unsaturated soils, numerical results confirm the conditions under which Richards's equation is valid...
Mass flows of endocrine disruptors in the Glatt River during varying weather conditions
Energy Technology Data Exchange (ETDEWEB)
Jonkers, Niels; Kohler, Hans-Peter E.; Dammshaeuser, Anna [Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Duebendorf (Switzerland); Giger, Walter [Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Duebendorf (Switzerland)], E-mail: giger@eawag.ch
2009-03-15
This study focused on the occurrence and behaviour in wastewater and surface waters of several phenolic endocrine disrupting compounds (EDCs) including parabens, alkylphenolic compounds, phenylphenol (PhP) and bisphenol A (BPA). Analytical procedures using solid-phase-extraction and LC-MS/MS techniques were applied to samples of influents and effluents of wastewater treatment plants (WWTPs) discharging into the Glatt River (Switzerland) as well as to river water samples. A mass flow analysis provided insight into the main sources and the fate of these contaminants during different weather conditions. Concentrations in influents were in the low {mu}g/L range for most analytes. Removal of parabens in the WWTPs was mostly above 99%. Nonylphenol polyethoxylates (A{sub 9}PEO) removal amounted to 98%, but in some cases nonylphenoxy acetic acid (A{sub 9}PEC) or nonylphenols (NP) were formed. In effluents, concentrations were highest for the A{sub 9}PEC, A{sub 9}PEO and NP. Concentrations in river water were in the high ng/L range for alkylphenolic compounds and in the low ng/L range for BPA, PhP and the parabens. During the sampling period, in which several rain events occurred, both water flows and mass flows varied strongly. Mass flows in WWTP effluents and in the river increased with increasing water flows for most compounds indicating that higher water flows do not lead necessarily to a proportional dilution of the pollutants. Throughout the low water flow period, mass flows predicted from the known inputs were similar to the actual mass flows at the end of the river for most analytes. For none of the EDCs, significant in-stream removal could be observed. In the periods with high water flows, mass flows in the river were much higher than can be explained by the initially defined sources. Discharge of untreated wastewater influent into the river was assessed as an additional source. Adding this source improved the mass balance for some, but not all of the analytes
CONJUGATE MODEL FOR HEAT AND MASS TRANSFER OF POROUS WALL IN THE HIGH TEMPERATURE GAS FLOW
Institute of Scientific and Technical Information of China (English)
A.F. Polyakov; D.L.Reviznikov; 沈青; 魏叔如
2001-01-01
Heat and mass transfer of a porous permeable wall in a high temperature gas dynamical flow is considered. Numerical simulation is conducted on the ground of the conjugate mathematical model which includes filtration and heat transfer equations in a porous body and boundary layer equations on its surface. Such an approach enables one to take into account complex interaction between heat and mass transfer in the gasdynamical flow and in the structure subjected to this flow.The main attention is given to the impact of the intraporous heat transfer intensity on the transpiration cooling efficiency.
Effects of mass flow rate and droplet velocity on surface heat flux during cryogen spray cooling
Energy Technology Data Exchange (ETDEWEB)
Karapetian, Emil [Department of Chemical Engineering and Material Sciences, University of California, Irvine, CA (United States); Aguilar, Guillermo [Department of Biomedical Engineering, University of California, Irvine, CA (United States); Kimel, Sol [Beckman Laser Institute, University of California, Irvine, CA (United States); Lavernia, Enrique J [Department of Chemical Engineering and Material Sciences, University of California, Irvine, CA (United States); Nelson, J Stuart [Department of Biomedical Engineering, University of California, Irvine, CA (United States)
2003-01-07
Cryogen spray cooling (CSC) is used to protect the epidermis during dermatologic laser surgery. To date, the relative influence of the fundamental spray parameters on surface cooling remains incompletely understood. This study explores the effects of mass flow rate and average droplet velocity on the surface heat flux during CSC. It is shown that the effect of mass flow rate on the surface heat flux is much more important compared to that of droplet velocity. However, for fully atomized sprays with small flow rates, droplet velocity can make a substantial difference in the surface heat flux. (note)
DEFF Research Database (Denmark)
Moeller, Jesper; Lichtenberg, Jacob; Andersen, Henrik Reif;
1999-01-01
This paper describes a new data structure, difference decision diagrams (DDDs), for representing a Boolean logic over inequalities of the form $x-y......This paper describes a new data structure, difference decision diagrams (DDDs), for representing a Boolean logic over inequalities of the form $x-y...
Indian Academy of Sciences (India)
Rudra Kanta Deka; Ashish Paul
2013-10-01
An analysis is performed to study the unsteady, incompressible, one-dimensional, free convective flow over an infinite moving vertical cylinder under combined buoyancy effects of heat and mass transfer with thermal and mass stratifications. Laplace transform technique is adopted for finding solutions for velocity, temperature and concentration with unit Prandtl and Schmidt numbers. Solutions of unsteady state for larger times are compared with the solutions of steady state. Velocity, temperature and concentration profiles are analysed for various sets of physical parameters. Skin friction, Nusselt number and Sherwood number are shown graphically. It has been found that the thermal as well as mass stratification affects the flow appreciably.
Base flow separation: A comparison of analytical and mass balance methods
Lott, Darline A.; Stewart, Mark T.
2016-04-01
Base flow is the ground water contribution to stream flow. Many activities, such as water resource management, calibrating hydrological and climate models, and studies of basin hydrology, require good estimates of base flow. The base flow component of stream flow is usually determined by separating a stream hydrograph into two components, base flow and runoff. Analytical methods, mathematical functions or algorithms used to calculate base flow directly from discharge, are the most widely used base flow separation methods and are often used without calibration to basin or gage-specific parameters other than basin area. In this study, six analytical methods are compared to a mass balance method, the conductivity mass-balance (CMB) method. The base flow index (BFI) values for 35 stream gages are obtained from each of the seven methods with each gage having at least two consecutive years of specific conductance data and 30 years of continuous discharge data. BFI is cumulative base flow divided by cumulative total discharge over the period of record of analysis. The BFI value is dimensionless, and always varies from 0 to 1. Areas of basins used in this study range from 27 km2 to 68,117 km2. BFI was first determined for the uncalibrated analytical methods. The parameters of each analytical method were then calibrated to produce BFI values as close to the CMB derived BFI values as possible. One of the methods, the power function (aQb + cQ) method, is inherently calibrated and was not recalibrated. The uncalibrated analytical methods have an average correlation coefficient of 0.43 when compared to CMB-derived values, and an average correlation coefficient of 0.93 when calibrated with the CMB method. Once calibrated, the analytical methods can closely reproduce the base flow values of a mass balance method. Therefore, it is recommended that analytical methods be calibrated against tracer or mass balance methods.
Hockney, Roger
1987-01-01
Algorithmic phase diagrams are a neat and compact representation of the results of comparing the execution time of several algorithms for the solution of the same problem. As an example, the recent results are shown of Gannon and Van Rosendale on the solution of multiple tridiagonal systems of equations in the form of such diagrams. The act of preparing these diagrams has revealed an unexpectedly complex relationship between the best algorithm and the number and size of the tridiagonal systems, which was not evident from the algebraic formulae in the original paper. Even so, for a particular computer, one diagram suffices to predict the best algorithm for all problems that are likely to be encountered the prediction being read directly from the diagram without complex calculation.
Experimental researches on mass and heat transfer in new typical cross-flow rotating packed bed
Institute of Scientific and Technical Information of China (English)
CHEN Haihui; ZENG Yingying; GAO Wenshuai
2006-01-01
New typical cross-flow Rotating Packed Bed(RPB)called multi-pulverizing RPB was manufactured.There is enough void in multi-pulverizing RPB,where liquid easily flows and is repeatedly pulverized by light packing,which decreases the material consumed,lightens the weight,and compacts the structure.Mass and heat transfer property in the new type PRB were studied by two experimental models.In the mass transfer model,the axial fan pumping gas press is only 100 Pa,mass transfer coefficient and volumetric mass transfer coefficient are similar to countercurrent RPB,which are an order quantity lager than that in the conventional packed tower.In the heat transfer experiment,the axial fan pumping gas press is only 120 Pa;volumetric heatwhich especially suits the treatment of large gas flow and lower gas pressure drop.
Numerical simulation of tsunami generation by cold volcanic mass flows at Augustine Volcano, Alaska
Waythomas, C.F.; Watts, P.; Walder, J.S.
2006-01-01
Many of the world's active volcanoes are situated on or near coastlines. During eruptions, diverse geophysical mass flows, including pyroclastic flows, debris avalanches, and lahars, can deliver large volumes of unconsolidated debris to the ocean in a short period of time and thereby generate tsunamis. Deposits of both hot and cold volcanic mass flows produced by eruptions of Aleutian arc volcanoes are exposed at many locations along the coastlines of the Bering Sea, North Pacific Ocean, and Cook Inlet, indicating that the flows entered the sea and in some cases may have initiated tsunamis. We evaluate the process of tsunami generation by cold granular subaerial volcanic mass flows using examples from Augustine Volcano in southern Cook Inlet. Augustine Volcano is the most historically active volcano in the Cook Inlet region, and future eruptions, should they lead to debris-avalanche formation and tsunami generation, could be hazardous to some coastal areas. Geological investigations at Augustine Volcano suggest that as many as 12-14 debris avalanches have reached the sea in the last 2000 years, and a debris avalanche emplaced during an A.D. 1883 eruption may have initiated a tsunami that was observed about 80 km east of the volcano at the village of English Bay (Nanwalek) on the coast of the southern Kenai Peninsula. Numerical simulation of mass-flow motion, tsunami generation, propagation, and inundation for Augustine Volcano indicate only modest wave generation by volcanic mass flows and localized wave effects. However, for east-directed mass flows entering Cook Inlet, tsunamis are capable of reaching the more populated coastlines of the southwestern Kenai Peninsula, where maximum water amplitudes of several meters are possible.
Kunikata, Satoru; Fukuda, Makoto; Yamamoto, Ken-ichiro; Yagi, Yutaka; Matsuda, Masato; Sakai, Kiyotaka
2009-01-01
Dialysis fluid flow and mass transfer rate of newly developed dialyzers were evaluated using mass transfer correlation equations of dialysis fluid-side film coefficient. Aqueous creatinine clearance and overall mass transfer coefficient for APS-15S (Asahi Kasei Kuraray) as a conventional dialyzer, and APS-15SA (Asahi Kasei Kuraray), PES-150Salpha (Nipro), FPX140 (Fresenius), and CS-1.6U (Toray) as newly developed dialyzers were obtained at a blood-side flow rate (QB) of 200 ml/min, dialysis fluid-side flow rates (QD) of 200-800 ml/min and a net filtration rate (QF) of 0 ml/min. Mass transfer correlation equations between Sherwood number (Sh) containing dialysis fluid-side mass transfer film coefficient and Reynolds number (Re) were formed for each dialyzer. The exponents of Re were 0.62 for APS-15S whereas approximately 0.5 for the newly developed dialyzers. The dialysis fluid-side mass transfer film coefficients of the newly developed dialyzers were higher than those of the conventional dialyzer. Based on the mass transfer correlation equations, introduction of short taper, full baffle of dialyzer jacket and further wave-shaped hollow fiber improves the dialysis fluid flow of the newly developed dialyzers.
Sedimentary history and mass flow structures of Chryse and Acidalia Planitiae, Mars
Tanaka, K.L.
1997-01-01
Geologic mapping and crater counting in Chryse and Acidalia Planitiae (GAP) reveal five major sedimentary deposits of Hesperian to Early Amazonian age, including (1) a mass flow deposited during the Early Hesperian near Deuteronilus Mensae (northeast of the map region) that may have resulted from the carving of Kasei Valles, >3000 km southwest of the exposed part of the deposit; (2) knobby plains material consisting of channel (likely; from Simud and Tiu Valles and possibly Ares and Shalbatana Valles) and mass-wasting deposits in central and eastern CAP; (3) material largely from Maja and Ares Valles emplaced in at least western and southern CAP (outcrops in southern Chryse Planitia developed thermokarst); (4) a thin mass flow covering much of southern Chryse Planitia that emanated from Simud and Tiu Valles; and (5) a thick, extensive (perhaps >3500 km across) mass flow deposit in central and northern CAP derived from accumulation and backflow of the preceding thin mass flow or perhaps melting of polar deposits. Other possible deposits may not be recognizable owing to burial by younger materials or a lack of morphologic signature. Various associated landforms appear to be consistent with the mass flow interpretations, including lobate and linear scarps along deposit edges, fractures related to desiccation of thick sediments, troughs, and ridges near the edges of the deposit indicative of secondary mass movement and deformation, pitted domes and fissure-fed flows possibly formed by sedimentary (mud) eruptions, and longitudinal channel grooves perhaps formed by roller vortices. No convincing evidence for paleoshorelines or stagnant ice sheets is found in CAP. These findings suggest that mass flow and hyperconcentrated flooding may have been the predominant processes of outflow-channel dissection in CAP. Elsewhere in the northern plains, similar landforms are prevalent. The mass flow interpretation does not require either multiple episodes of extraordinarily high
一种实用的输电网潮流图自动生成算法%A Practical Automatic Generation Algorithm of Power Flow Diagram
Institute of Scientific and Technical Information of China (English)
徐丽燕; 陈文静; 苏运光; 孙云枫
2015-01-01
Based on the general characteristics of the electricity transmission grid trend diagram ,this paper comprehensively studies a variety of automatic layout and wiring method ,proposes a practical electricity transmission grid trend chart automatic generation algorithm ,and has set up an experiment to verify its effectiveness.%文章针对输电网潮流图的一般特点,综合研究了多种自动布局与布线方法,提出了一种实用性较强的输电网潮流图自动生成算法,并已通过实验验证其有效性.
NUMERICAL ANALYSIS OF FLUID FLOW AND ADDED MASS INDUCED BY VIBRATION OF STRUCTURE
Institute of Scientific and Technical Information of China (English)
SU Li; LI Shu-juan; TANG Guo-an
2005-01-01
The fluid flow induced by light-density, low-stiffness structures was treated as inviscid, incompressible irrotational and steady plane flow. On the basis of the dipole configuration method, a singularity distribution method of distributing sources/sinks and dipoles on interfaces of the structure and fluid was developed to solve the problem of fluid flow induced by the vibration of common structures, such as columns and columns with fins,deduce the expression of kinetic energy of the fluid flow, and obtain the added mass finally.The calculational instances with analytical solutions prove the reliability of this method.
Estimating kinetic mass transfer by resting-period measurements in flow-interruption tracer tests.
Gong, R; Lu, C; Wu, W-M; Cheng, H; Gu, B; Watson, D B; Criddle, C S; Kitanidis, P K; Brooks, S C; Jardine, P M; Luo, J
2010-09-20
Flow-interruption tracer test is an effective approach to identify kinetic mass transfer processes for solute transport in subsurface media. By switching well pumping and resting, one may alter the dominant transport mechanism and generate special concentration patterns for identifying kinetic mass transfer processes. In the present research, we conducted three-phase (i.e., pumping, resting, and pumping) field-scale flow-interruption tracer tests using a conservative tracer bromide in a multiple-well system installed at the US Department of Energy Site, Oak Ridge, TN. A novel modeling approach based on the resting-period measurements was developed to estimate the mass transfer parameters. This approach completely relied on the measured breakthrough curves without requiring detailed aquifer characterization and solving transport equations in nonuniform, transient flow fields. Additional measurements, including hydraulic heads and tracer concentrations in large pumping wells, were taken to justify the assumption that mass transfer processes dominated concentration change during resting periods. The developed approach can be conveniently applied to any linear mass transfer model. Both first-order and multirate mass transfer models were applied to analyze the breakthrough curves at various monitoring wells. The multirate mass transfer model was capable of jointly fitting breakthrough curve behavior, showing the effectiveness and flexibility for incorporating aquifer heterogeneity and scale effects in upscaling effective mass transfer models.
Inductively generating Euler diagrams.
Stapleton, Gem; Rodgers, Peter; Howse, John; Zhang, Leishi
2011-01-01
Euler diagrams have a wide variety of uses, from information visualization to logical reasoning. In all of their application areas, the ability to automatically layout Euler diagrams brings considerable benefits. In this paper, we present a novel approach to Euler diagram generation. We develop certain graphs associated with Euler diagrams in order to allow curves to be added by finding cycles in these graphs. This permits us to build Euler diagrams inductively, adding one curve at a time. Our technique is adaptable, allowing the easy specification, and enforcement, of sets of well-formedness conditions; we present a series of results that identify properties of cycles that correspond to the well-formedness conditions. This improves upon other contributions toward the automated generation of Euler diagrams which implicitly assume some fixed set of well-formedness conditions must hold. In addition, unlike most of these other generation methods, our technique allows any abstract description to be drawn as an Euler diagram. To establish the utility of the approach, a prototype implementation has been developed.
Impact of Elevated PCO2 on Mass Flow of Reduced Nitrogen in Trees
Institute of Scientific and Technical Information of China (English)
Xi-Ping Liu
2006-01-01
To analyze the effects of elevated carbon dioxide concentration (PCO2) on the mass flow of reduced nitrogen (N) in the phloem and xylem of trees, juvenile beech (Fagus sylvatica L.) and spruce (Picea abies (L.)Karst.) were grown in phytotrons and exposed to ambient and elevated PCO2 (plus 687.5 mg/m3 CO2) for three growing seasons. Elevated PCO2 significantly decreased the mass flow of N from the shoot to roots of beech by significantly reducing the concentration of soluble amino compounds in the phloem, even if the area of conductive phloem of cross-sectional bark tissue was significantly increased, because of less callus deposition in the sieve elements. In spruce, the downward mass flow of reduced N also tended to be decreased, similar to that in beech. Resembling findings in the phloem, N mass flow from roots to shoot in both tree species was significantly diminished owing to significantly reduced concentrations of amino compounds in the xylem and a lower transpiration rate. Therefore, the mass flow of reduced N between shoots and roots of trees was mainly governed by the concentrations of soluble amino compounds in the phloem and xylem in relation to the loading of reduced N in both long-distance transport pathways.
Anatomy and function relation in the coronary tree: from bifurcations to myocardial flow and mass.
Kassab, Ghassan S; Finet, Gerard
2015-01-01
The study of the structure-function relation of coronary bifurcations is necessary not only to understand the design of the vasculature but also to use this understanding to restore structure and hence function. The objective of this review is to provide quantitative relations between bifurcation anatomy or geometry, flow distribution in the bifurcation and degree of perfused myocardial mass in order to establish practical rules to guide optimal treatment of bifurcations including side branches (SB). We use the scaling law between flow and diameter, conservation of mass and the scaling law between myocardial mass and diameter to provide geometric relations between the segment diameters of a bifurcation, flow fraction distribution in the SB, and the percentage of myocardial mass perfused by the SB. We demonstrate that the assessment of the functional significance of an SB for intervention should not only be based on the diameter of the SB but also on the diameter of the mother vessel as well as the diameter of the proximal main artery, as these dictate the flow fraction distribution and perfused myocardial mass, respectively. The geometric and flow rules for a bifurcation are extended to a trifurcation to ensure optimal therapy scaling rules for any branching pattern.
Experimental investigation of the mass flow gain factor in a draft tube with cavitation vortex rope
Landry, C.; Favrel, A.; Müller, A.; Yamamoto, K.; Alligné, S.; Avellan, F.
2017-04-01
At off-design operating operations, cavitating flow is often observed in hydraulic machines. The presence of a cavitation vortex rope may induce draft tube surge and electrical power swings at part load and full load operations. The stability analysis of these operating conditions requires a numerical pipe model taking into account the complexity of the two-phase flow. Among the hydroacoustic parameters describing the cavitating draft tube flow in the numerical model, the mass flow gain factor, representing the mass excitation source expressed as the rate of change of the cavitation volume as a function of the discharge, remains difficult to model. This paper presents a quasi-static method to estimate the mass flow gain factor in the draft tube for a given cavitation vortex rope volume in the case of a reduced scale physical model of a ν = 0.27 Francis turbine. The methodology is based on an experimental identification of the natural frequency of the test rig hydraulic system for different Thoma numbers. With the identification of the natural frequency, it is possible to model the wave speed, the cavitation compliance and the volume of the cavitation vortex rope. By applying this new methodology for different discharge values, it becomes possible to identify the mass flow gain factor and improve the accuracy of the system stability analysis.
Energy Technology Data Exchange (ETDEWEB)
Surek, D. [Fachbereich Maschinenbau, Fachhochschule Merseburg (Germany)
1995-03-01
The interruptor makes the working principle of side channel machines with their high pressure possible. The work transmission and the characteristic of side channel pumps are also determined by the thermodynamic and flow processes at the interrupter. To set up a calculation model of side channel compressors and their design, it is essential to know the flow processes at the interrupter, particularly from the rotor via the interrupter when giving up work to the mass flow transported to the rotor. Therefore, the mass flow flowing over is examined as a precondition for the design, based on the energy and mass flow balance at the interrupter and experimental investigations. The mass flow ratios m{sub U}/dot m{sub S} are given depending on the delivery and pressure figures. The circulationdelivery for the internal mass flow m{sub U} is defined and proved. The product of {phi}.m{sub U}/m{sub S} of a side channel machine is a constant over the whole working range. (orig.) [Deutsch] Der Unterbrecher ermoeglicht das Arbeitsprinzip von Seitenkanalmaschinen mit ihrer grossen Druckzahl. Die Arbeitsuebertragung und die Kennliniencharakteristik von Seitenkanalpumpen werden aber auch ganz wesentlich von den thermodynamischen und Stroemungsvorgaengen am Unterbrecher bestimmt. Fuer die Aufstellung eines Berechnungsmodells von Seitenkanalverdichtern und deren Auslegung ist die Kenntnis der Stroemungsvorgaenge am Unterbrecher, insbesonder des vom Laufrad ueber den Unterbrecher bei Arbeitsabgabe an das Laufrad transportierten Massestromes, unerlaesslich. Deshalb wird auf der Grundlage der Energie- und Massestrombilanz am Unterbrecher und experimenteller Untersuchungen der ueberstroemende Massestrom als Voraussetzung fuer die Auslegung untersucht. Die Massestromverhaeltnisse m{sub U}/m{sub S}, werden in Abhaengigkeit der Lieferzahl und Druckzahl angegeben. Fuer den inneren Massestrom m{sub U} wird die Zirkulationslieferzahl definiert und nachgewiesen. Das Produkt aus {phi}.m{sub U
Unstable mass-outflows in geometrically thick accretion flows around black holes
Okuda, Toru
2015-01-01
Accretion flows around black holes generally result in mass-outflows that exhibit irregular behavior quite often. Using 2D time-dependent hydrodynamical calculations, we show that the mass-outflow is unstable in the cases of thick accretion flows such as the low angular momentum accretion flow and the advection-dominated accretion flow. For the low angular momentum flow, the inward accreting matter on the equatorial plane interacts with the outflowing gas along the rotational axis and the centrifugally supported oblique shock is formed at the interface of both the flows, when the viscosity parameter $\\alpha$ is as small as $\\alpha \\le 10^{-3}$. The hot and rarefied blobs, which result in the eruptive mass-outflow, are generated in the inner shocked region and grow up toward the outer boundary. The advection-dominated accretion flow attains finally in the form of a torus disc with the inner edge of the disc at $3R_{\\rm g} \\le r \\le 6R_{\\rm g}$ and the center at $6R_ {\\rm g} \\le r \\le 10R_{\\rm g}$, and a series...
Institute of Scientific and Technical Information of China (English)
赵卫萍; 张红超; 庹琨明; 杨涛; 孟玲; 李环
2015-01-01
OBJECTIVE To improve the scientific management of central sterile supply department and work quality through the visual management flow diagram .METHODS The visual flow management team was established to de‐velop the visual flow diagram and organize all the staff to learn the concepts ,requirements ,and contents of the visual management flow diagram ,which was served as one of the onsite management modes and was applied for the management of the instruments ,infection control ,and instrument packages .RESULTS As compared with the qualified rate of the instruments in Jul-Sep ,2013 ,it was increased in Jul-Sep ,2014 .The qualified rate of quali‐ty examination of instruments was 97 .57% in 2013 ,99 .75% in 2014 ;the qualified rate of number of instrument packages was 95 .21% in 2013 ,99 .55% in 2014 ;the qualified rate of infection control was 94 .00% in 2013 , 98 .49% in 2014 ;the qualified rate of timely supply of instruments was 95 .80% in 2013 ,99 .44% in 2014 . CONCLUSIONS The visual flow diagram can achieve significant effect on actual management of the central sterile supply department ,raise the work quality and efficiency of the departments ,and make the work flow of the supply department standardized ,the quality control and teaching training visualized;it is a visualized ,high‐efficiency flow management mode .%目的：通过目视流程图解在消毒供应室中的应用，提高供应室科学化管理水平和工作质量。方法科室成立目视流程管理小组，制作目视流程图解，组织全科人员学习目视管理流程图解的概念、要求和内容，将其作为现场管理的模式之一，应用于仪器设备、感染控制、器械包管理。结果器械合格率2013年7－9月与2014年7－9月相比均有提高，其中器械质量检查、器械包装数量、感染控制、器械及时供应等合格率，2013年分别为97．57％、95．21％、94．00％、95．80％；2014年分别为99．75％、99．55％、98
Ridder, van de L.; Hakvoort, W.B.J.; Dijk, van J.; Lötters, J.C.; Boer, de A.
2014-01-01
In this paper the influence of external vibrations on the measurement value of a Coriolis mass-flow meter (CMFM) for low flows is investigated and quantified. Model results are compared with experimental results to improve the knowledge on how external vibrations affect the mass-flow measurement val
Mass accretion flows in the high-mass star forming complex NGC 6334
Sánchez-Monge, Á.; Schilke, P.; Zernickel, A.; Schmiedeke, A.; Möller, Th.; Qin, S.-L.
2016-05-01
The formation of high-mass stars is one of the major topics of astrophysical research, in particular the process of accretion from large-scale clouds down to small-scale cores. We have selected the nearby, filamentary, high-mass star forming complex NGC 6334 to study the gas velocity at different scales and probe the infall rates onto the protostellar cores embedded in the NGC 6334-I and I(N) clusters. This study makes use of single-dish and interferometric submillimeter observations, complemented with 3D numerical non-LTE radiative transfer modeling. We measure a mass accretion rate of 10-5 M⊙ yr-1 throughout the filament increasing up to 10-3 M⊙ yr-1 towards the densest regions where high-mass stars are forming. At smaller scales, our 3D model is consistent with accretion rates of 10-3 M⊙ yr-1 towards the clusters, and 10-4 M⊙ yr-1 onto the protostars.
The respective roles of bulk friction and slip velocity during a granular mass flow
Staron, Lydie
2016-04-01
Catastrophic granular mass flows form an important natural hazard. Mitigation has motivated numerous studies on the properties of natural granular flows, and in particular, their ability to travel long distances away from the release point. The mobility of granular flows is commonly characterised through the definition of rheological properties and effective friction. Yet, it is widely accepted that the description in term of effective friction may include various lubrication effects, softening at the base of the flow and large slip velocities being a most likely one. In this case, flow bulk properties may obliterate the flow boundary conditions. In this contribution, we investigate how disentangling bulk properties from boundary conditions may improve our understanding of the flow. Using discrete simulations, we induce increasing slip velocities in different flow configurations. We show that increased mobility may be achieved without changing bulk properties. The results are interpreted in terms of a Robin-Navier slip condition and implemented in a continuum Navier-Stokes solver. We quantify the respective role of rheological bulk properties and boundary conditions in the general behaviour of a transient mass flow. We show that omitting the description of boundary conditions leads to misinterpretation of the flow properties. The outcome is discussed in terms of models reliability. References P.-Y. Lagrée et al, The granular column collapse as a continuum: validity of a two-dimensional Navier-Stokes model with the mu(I) rheology, J. Fluid Mech. 686, 378-408 (2011) L. Staron and E. Lajeunesse, Understanding how the volume affects the mobility of dry debris flows, Geophys. Res. Lett. 36, L12402 (2009) L. Staron, Mobility of long-runout rock flows: a discrete numerical investigation, Geophys. J. Int. 172, 455-463 (2008)
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Seepage flow in fractured rock mass due to surface infiltration is a saturated-unsaturated seepage process. Aimed at rock mass with large fracture density, which can be equivalent to continuum, a mathematical model for saturated-unsaturated seepage flow in fractured rock mass due to surface infiltration was established in this paper. The Galerkin finite element method was used in numerical simulation and a finite element program used to calculate saturated-unsaturated seepage flow due to surface infiltration was worked out. A model experiment was employed examine the reasonableness of the program. The results show that the proposed model and program are reasonable. The application of the analysis method in this paper in an engineering project shows that the method is reliable and feasible.
A Twophase Multirate-Mass Transfer Model for Flow and Transport in Porous Media
Dentz, M.; Tecklenburg, J.; Neuweiler, I.; Carrera, J.
2015-12-01
We present an upscaled non-local model for two-phase flow and transport in highly heterogeneous porous media. The media under consideration are characterized by sharp contrasts in the hydraulic properties typical for fractured porous media, for example. A two-scale expansion gives an upscaled flow and transport formulation that models multiratemass transfer between mobile (fracture) and immobile (matrix) medium portions. The evolution of saturation due to viscous dominated flow in the mobile domain and mass exchange with the immobile zones through capillary countercurrent flow. The medium heterogeneity is mapped onto the mass transfer parameters, which are encoded in a memory functionthat describes the non-local flux between mobile and immobile zones. The upscaled model is parameterized by the medium heterogeneity and the distribution of hydraulic parameters. Breakthrough of the displaced fluidshows characteristic heavy tails due to fluid retention in immobile zones.
Feynman Diagrams for Beginners
Kumericki, Kresimir
2016-01-01
We give a short introduction to Feynman diagrams, with many exercises. Text is targeted at students who had little or no prior exposure to quantum field theory. We present condensed description of single-particle Dirac equation, free quantum fields and construction of Feynman amplitude using Feynman diagrams. As an example, we give a detailed calculation of cross-section for annihilation of electron and positron into a muon pair. We also show how such calculations are done with the aid of computer.
Gorder, Riley; Aliseda, Alberto
2009-11-01
The carotid artery bifurcation (CAB) is one of the leading site for atherosclerosis, a major cause of mortality and morbidity in the developed world. The specific mechanisms by which perturbed flow at the bifurcation and in the carotid bulge promotes plaque formation and growth are not fully understood. Shear stress, mass transport, and flow residence times are considered dominant factors. Shear stress causes restructuring of endothelial cells at the arterial wall which changes the wall's permeability. Long residence times are associated with enhanced mass transport through increased diffusion of lipids and white blood cells into the arterial wall. Although momentum and mass transfer are traditionally coupled by correlations similar to Reynolds Analogy, the complex flow patterns present in this region due to the pulsatile, transitional, detached flow associated with the complex geometry makes the validity of commonly accepted assumptions uncertain. We create solid models of the CAB from MRI or ultrasound medical images, build flow phantoms on clear polyester resin and use an IOR matching, blood mimicking, working fluid. Using PIV and dye injection techniques the shear stress and scalar transport are experimentally investigated. Our goal is to establish a quantitative relationship between momentum and mass transfer under a wide range of physiologically normal and pathological conditions.
Reactor mass flow data base prepared for the nonproliferation alternative systems assessment program
Energy Technology Data Exchange (ETDEWEB)
Primm III, R.T.C
1981-02-01
This report presents charge and discharge mass flow data for reactors judged to have received sufficient technical development to enable them to be demonstrated or commercially available by the year 2000. Brief descriptions of the reactors and fuel cycles evaluated are presented. A discussion of the neutronics methods used to produce the mass flow data is provided. Detailed charge and discharge fuel isotopics are presented. U/sub 3/O/sub 8/, separative work, and fissile material requirements are computed and provided for each fuel cycle.
Directory of Open Access Journals (Sweden)
Mayrhofer Susanne
2014-10-01
Full Text Available Ammonoid mass occurrences of Late Triassic age were investigated in sections from A şağlyaylabel and Yukarlyaylabel, which are located in the Taurus Platform-Units of eastern Turkey. The cephalopod beds are almost monospecific, with > 99.9 % of individuals from the ceratitic genus Kasimlarceltites, which comprises more than hundreds of millions of ammonoid specimens. The ontogenetic composition of the event fauna varies from bed to bed, suggesting that these redeposited shell-rich sediments had different source areas. The geographical extent of the mass occurrence can be traced over large areas up to 10 km2. Each of the Early Carnian (Julian 2 ammonoid mass occurrences signifies a single storm (e.g. storm-wave action or tectonic event (e.g. earthquake that caused gravity flows and turbidity currents. Three types of ammonoid accumulation deposits are distinguished by their genesis: 1 matrix-supported floatstones, produced by low density debris flows, 2 mixed floatstones and packstones formed by high density debris flows, and 3 densely ammonoid shell-supported packstones which result from turbidity currents. Two-dimensional calculations on the mass occurrences, based on sectioning, reveal aligned ammonoid shells, implying transport in a diluted sediment. The ammonoid shells are predominantely redeposited, preserved as mixed autochthonous/parautochnonous/ allochthonous communities based on biogenic and sedimentological concentration mechanisms ( = in-situ or post-mortem deposited. This taphonomic evaluation of the Kasimlarceltites beds thus reveals new insights into the environment of deposition of the Carnian section, namely that it had a proximal position along a carbonate platform edge that was influenced by a nearby shallow water regime. The Kasimlarceltites-abundance zone is a marker-zone in the study area, developed during the drowning of a shallow water platform, which can be traceable over long distances.
Mayrhofer, Susanne; Mayrhofer, Susanne
2014-10-01
Ammonoid mass occurrences of Late Triassic age were investigated in sections from A şağlyaylabel and Yukarlyaylabel, which are located in the Taurus Platform-Units of eastern Turkey. The cephalopod beds are almost monospecific, with > 99.9 % of individuals from the ceratitic genus Kasimlarceltites, which comprises more than hundreds of millions of ammonoid specimens. The ontogenetic composition of the event fauna varies from bed to bed, suggesting that these redeposited shell-rich sediments had different source areas. The geographical extent of the mass occurrence can be traced over large areas up to 10 km2. Each of the Early Carnian (Julian 2) ammonoid mass occurrences signifies a single storm (e.g. storm-wave action) or tectonic event (e.g. earthquake) that caused gravity flows and turbidity currents. Three types of ammonoid accumulation deposits are distinguished by their genesis: 1) matrix-supported floatstones, produced by low density debris flows, 2) mixed floatstones and packstones formed by high density debris flows, and 3) densely ammonoid shell-supported packstones which result from turbidity currents. Two-dimensional calculations on the mass occurrences, based on sectioning, reveal aligned ammonoid shells, implying transport in a diluted sediment. The ammonoid shells are predominantely redeposited, preserved as mixed autochthonous/parautochnonous/ allochthonous communities based on biogenic and sedimentological concentration mechanisms ( = in-situ or post-mortem deposited). This taphonomic evaluation of the Kasimlarceltites beds thus reveals new insights into the environment of deposition of the Carnian section, namely that it had a proximal position along a carbonate platform edge that was influenced by a nearby shallow water regime. The Kasimlarceltites-abundance zone is a marker-zone in the study area, developed during the drowning of a shallow water platform, which can be traceable over long distances.
Bayesian inference in mass flow simulations - from back calculation to prediction
Kofler, Andreas; Fischer, Jan-Thomas; Hellweger, Valentin; Huber, Andreas; Mergili, Martin; Pudasaini, Shiva; Fellin, Wolfgang; Oberguggenberger, Michael
2017-04-01
Mass flow simulations are an integral part of hazard assessment. Determining the hazard potential requires a multidisciplinary approach, including different scientific fields such as geomorphology, meteorology, physics, civil engineering and mathematics. An important task in snow avalanche simulation is to predict process intensities (runout, flow velocity and depth, ...). The application of probabilistic methods allows one to develop a comprehensive simulation concept, ranging from back to forward calculation and finally to prediction of mass flow events. In this context optimized parameter sets for the used simulation model or intensities of the modeled mass flow process (e.g. runout distances) are represented by probability distributions. Existing deterministic flow models, in particular with respect to snow avalanche dynamics, contain several parameters (e.g. friction). Some of these parameters are more conceptual than physical and their direct measurement in the field is hardly possible. Hence, parameters have to be optimized by matching simulation results to field observations. This inverse problem can be solved by a Bayesian approach (Markov chain Monte Carlo). The optimization process yields parameter distributions, that can be utilized for probabilistic reconstruction and prediction of avalanche events. Arising challenges include the limited amount of observations, correlations appearing in model parameters or observed avalanche characteristics (e.g. velocity and runout) and the accurate handling of ensemble simulations, always taking into account the related uncertainties. Here we present an operational Bayesian simulation framework with r.avaflow, the open source GIS simulation model for granular avalanches and debris flows.
A new two-phase erosion-deposition model for mass flows
Pudasaini, Shiva P.; Fischer, Jan-Thomas
2016-04-01
Erosion, entrainment and deposition are complex and dominant, but yet poorly understood, mechanical processes in geophysical mass flows. Here, we propose a novel, two-phase, erosion-deposition model capable of adequately describing these complex phenomena commonly observed in landslides, avalanches, debris flows and bedload transports. The model enhances an existing general two-phase mass flow model (Pudasaini, 2012) by introducing a two-phase variably saturated erodible basal morphology. The adaptive basal morphology allows for the evolution of erosion-deposition-depths, incorporating the inherent physical process and rheological changes of the flowing mixture. With rigorous derivation, we show that appropriate incorporation of the mass and momentum productions and losses in conservative model formulation is essential for the physically correct and mathematically consistent description of erosion-entrainment-deposition processes. Simulation indicates a sharp erosion-front and steady-state-rear erosion depth. The model appropriately captures the emergence and propagation of complex frontal surge dynamics associated with the frontal ambient-drag which is a new hypothesis associated with erosion. The novel enhanced real two-phase model also allows for simulating fluid-run-off during the deposition process. The model resembles laboratory experiments for particle-fluid mixture flows and reveals some major aspects of the mechanics associated with erosion, entrainment and deposition. Reference: Shiva P. Pudasaini (2012): A general two-phase debris flow model. J. Geophys. Res., 117, F03010, doi: 10.1029/2011JF002186.
Mass flow-rate control unit to calibrate hot-wire sensors
Energy Technology Data Exchange (ETDEWEB)
Durst, F.; Uensal, B. [FMP Technology GmbH, Erlangen (Germany); Haddad, K. [FMP Technology GmbH, Erlangen (Germany); Friedrich-Alexander-Universitaet Erlangen-Nuernberg, LSTM-Erlangen, Institute of Fluid Mechanics, Erlangen (Germany); Al-Salaymeh, A.; Eid, Shadi [University of Jordan, Mechanical Engineering Department, Faculty of Engineering and Technology, Amman (Jordan)
2008-02-15
Hot-wire anemometry is a measuring technique that is widely employed in fluid mechanics research to study the velocity fields of gas flows. It is general practice to calibrate hot-wire sensors against velocity. Calibrations are usually carried out under atmospheric pressure conditions and these suggest that the wire is sensitive to the instantaneous local volume flow rate. It is pointed out, however, that hot wires are sensitive to the instantaneous local mass flow rate and, of course, also to the gas heat conductivity. To calibrate hot wires with respect to mass flow rates per unit area, i.e., with respect to ({rho}U), requires special calibration test rigs. Such a device is described and its application is summarized within the ({rho}U) range 0.1-25 kg/m{sup 2} s. Calibrations are shown to yield the same hot-wire response curves for density variations in the range 1-7 kg/m{sup 3}. The application of the calibrated wires to measure pulsating mass flows is demonstrated, and suggestions are made for carrying out extensive calibrations to yield the ({rho}U) wire response as a basis for advanced fluid mechanics research on ({rho}U) data in density-varying flows. (orig.)
Laboratory procedures and data reduction techniques to determine rheologic properties of mass flows
Holmes, R.R.; Huizinga, R.J.; Brown, S.M.; Jobson, H.E.
1993-01-01
Determining the rheologic properties of coarse- grained mass flows is an important step to mathematically simulate potential inundation zones. Using the vertically rotating flume designed and built by the U.S. Geological Survey, laboratory procedures and subsequent data reduction have been developed to estimate shear stresses and strain rates of various flow materials. Although direct measurement of shear stress and strain rate currently (1992) are not possible in the vertically rotating flume, methods were derived to estimate these values from measurements of flow geometry, surface velocity, and flume velocity.
Effects of mass transfer on MHD flow of casson fluid with chemical reaction and suction
Directory of Open Access Journals (Sweden)
S. A. Shehzad
2013-03-01
Full Text Available Effect of mass transfer in the magnetohydrodynamic flow of a Casson fluid over a porous stretching sheet is addressed in the presence of a chemical reaction. A series solution for the resulting nonlinear flow is computed. The skin friction coefficient and local Sherwood number are analyzed through numerical values for various parameters of interest. The velocity and concentration fields are illustrated for several pertinent flow parameters. We observed that the Casson parameter and Hartman number have similar effects on the velocity in a qualitative sense. We further analyzed that the concentration profile decreases rapidly in comparison to the fluid velocity when we increased the values of the suction parameter.
BIFURCATION OF FLOW AND MASS TRANSPORT IN A CURVED BLOOD VESSEL
Institute of Scientific and Technical Information of China (English)
TAN Wenchang(谭文长); WEI Lan(魏兰); ZHAO Yaohua(赵耀华); TAKASHI Masuoka
2003-01-01
A numerical analysis of flow and concentration fields of macromolecules in a slightly curved blood vessel was carried out. Based on these results, the effect of the bifurcation of a flow on the mass transport in a curved blood vessel was discussed. The macromolecules turned out to be easier to deposit in the inner part of the curved blood vessel near the critical Dean number. Once the Dean number is higher than the critical number, the bifurcation of the flow appears. This bifurcation can prevent macromolecules from concentrating in the inner part of the curved blood vessel. This result is helpful for understanding the possible correlations between the blood dynamics and atherosclerosis.
Liquid-liquid Slug Flow in a Microchannel Reactor and its Mass Transfer Properties - A Review
Directory of Open Access Journals (Sweden)
Rahul Antony
2014-10-01
Full Text Available Mass transfer is a basic phenomenon behind many processes like reaction, absorption, extraction etc. Mass transfer plays a significant role in microfluidic systems where the chemical / biological process systems are shrinkened down to a micro scale. Micro reactor system, with its high compatibility and performance, gains a wide interest among the researchers in the recent years. Micro structured reac-tors holds advantages over the conventional types in chemical processes. The significance of micro re-actor not limited to its scalability but to energy efficiency, on-site / on-demand production, reliability, safety, highly controlled outputs, etc. Liquid-liquid two phase reaction in a microreactor system is highly demandable when both reactants are liquids or when air medium cannot be suitable. This arti-cle overviews various liquid-liquid flow regimes in a microchannel. Discussions on the hydrodynamics of flow in micro scale are made. Considering the importance of mass transfer in liquid-liquid systems and the advantage of slug regime over other regimes, the article focuses especially on the mass trans-fer between two liquid phases in slug flow and the details of experimental studies carried out in this area. The advantages of slug flow over other flow regimes in micro structured reactor applications are showcased. © 2014 BCREC UNDIP. All rights reservedReceived: 31st May 2014; Revised: 6th August 2014; Accepted: 14th August 2014How to Cite: Antony, R., Giri Nandagopal, M.S., Sreekumar, N., Rangabhashiyam, S., Selvaraju, N. (2014. Liquid-liquid Slug Flow in a Microchannel Reactor and its Mass Transfer Properties - A Review. Bulletin of Chemical Reaction Engineering & Catalysis,9(3: 207-223. (doi:10.9767/bcrec.9.3.6977.207-223Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.3.6977.207-223
Numerical investigation of interface region flows in mass spectrometers: ion transport
Energy Technology Data Exchange (ETDEWEB)
Jugroot, Manish [Institute for Aerospace Studies, University of Toronto, 4925 Dufferin Street, Toronto, Ontario, M3H 5T6 (Canada); Groth, Clinton P T [Institute for Aerospace Studies, University of Toronto, 4925 Dufferin Street, Toronto, Ontario, M3H 5T6 (Canada); Thomson, Bruce A [MDS SCIEX, 71 Four Valley Drive, Concord, Ontario, L4K 4V8 (Canada); Baranov, Vladimir [MDS SCIEX, 71 Four Valley Drive, Concord, Ontario, L4K 4V8 (Canada); Collings, Bruce A [MDS SCIEX, 71 Four Valley Drive, Concord, Ontario, L4K 4V8 (Canada)
2004-02-21
The transport of free ions through highly under-expanded jet flows of neutral gases and in the presence of applied electric fields is investigated by continuum-based numerical simulations. In particular, numerical results are described that are relevant to ion flows occurring in the interface region of mass spectrometer systems. A five-moment mathematical model and parallel multi-block numerical solution procedure are developed for predicting the ion transport. The model incorporates the effects of ion-neutral collision processes and is used in conjunction with a Navier-Stokes model and flow solver for the neutral gas to examine the key features of the ion motion. The influences of the neutral gas flow, electric field, and flow field geometry on ion mobility are all carefully assessed. Several ions of varying mass and charge are considered, and the relative importance of competing effects (i.e. electric field and ion-neutral collision effects) is discussed. The capability of controlling the charged particle motions through a combination of directed neutral flow and applied electric field is demonstrated for high-speed, hypersonic jet flows.
Review of zero-net-mass-flux jet and its application in separation flow control
Institute of Scientific and Technical Information of China (English)
2008-01-01
Since the zero-net-mass-flux (ZNMF) jet was first used as a laboratory flow control method in 1990’s, it has attracted much attention. The ZNMF jet has unique features such as compact actuator, no requirement for external air supply, complex piping, etc., and becomes a hot topic research subject in fluid mechanics. This review introduces the state of the art in the development of ZNMF jet in the quiescent fluid, the interaction of the ZNMF jet with the cross flow and its application in the separation flow control. The evolution of the vortex ring/pair and the spacial flow structure of the ZNMF in quicent fluid or cross flow are presented, as well as the key parameter effects. At last, the applications of ZNMF jet in the wake control of the circular cylinder, the separation control on the airfoil and the aerodynamic force or moment control on MAV/UAV are presented.
Review of zero-net-mass-flux jet and its application in separation flow control
Institute of Scientific and Technical Information of China (English)
ZHANG PanFeng; WANG JinJun; FENG LiHao
2008-01-01
Since the zero-net-mass-flux (ZNMF) jet was first used as a laboratory flow control method in 1990's, it has attracted much attention. The ZNMF jet has unique features such as compact actuator, no requirement for external air supply, complex piping, etc., and becomes a hot topic research subject in fluid mechanics. This review introduces the state of the art in the development of ZNMF jet in the quiescent fluid, the interaction of the ZNMF jet with the cross flow and its application in the separation flow control. The evolution of the vortex ring/pair and the spacial flow structure of the ZNMF in quicent fluid or cross flow are presented, as well as the key parameter effects. At last, the applications of ZNMF jet in the wake control of the circular cylinder, the separation control on the airfoil and the aerodynamic force or moment control on MAV/UAV are presented.
Numerical calculations of mass transfer flow in semi-detached binary systems. [of stars
Edwards, D. A.; Pringle, J. E.
1987-01-01
The details of the mass transfer flow near the inner Lagrangian point in a semidetached binary system are numerically calculated. A polytropic equation of state with n = 3/2 is used. The dependence of the mass transfer rate on the degree to which the star overfills its Roche lobe is calculated, and good agreement with previous analytic estimates is found. The variation of mass transfer rate which occurs if the binary system has a small eccentricity is calculated and is used to cast doubt on the model for superhumps in dwarf novae proposed by Papaloizou and Pringle (1979).
Local Heat and Mass Transfer for Gas—Solid Two Phase Flow in CFB
Institute of Scientific and Technical Information of China (English)
FengLu; Ming－HengShi
1994-01-01
An experimental investigation on the flow characteristics and the local heat and mass transfer between coarse wet particles and hot gas in the circulaing fluidized bed(CFB) has been performed.A twothermocouple contrast method was developed to measure the local gas and solid temperature along the height of the bed.The influences of air superficial velocity,solid rate and initial moisture content on the local heat and mass transfer between gas and sloid were examined.The correlations of heat and mass transfer coefficients between gas and coarse wet particles in CFB were obtained.
Digital Repository Service at National Institute of Oceanography (India)
Vethamony, P.; Chandramohan, P.; Sastry, J.S.; Narasimhan, S.
flow theory. Variations of added-mass and damping coefficients with respect to water depth, wave period and float size have been obtained. Variations of added-mass and damping coefficients with wave period show that these hydrodynamic coefficients...
Modeling, design, fabrication and characterization of a micro Coriolis mass flow sensor
Haneveld, J.; Lammerink, T. S. J.; de Boer, M. J.; Sanders, R. G. P.; Mehendale, A.; Lötters, J. C.; Dijkstra, M.; Wiegerink, R. J.
2010-12-01
This paper discusses the modeling, design and realization of micromachined Coriolis mass flow sensors. A lumped element model is used to analyze and predict the sensor performance. The model is used to design a sensor for a flow range of 0-1.2 g h-1 with a maximum pressure drop of 1 bar. The sensor was realized using semi-circular channels just beneath the surface of a silicon wafer. The channels have thin silicon nitride walls to minimize the channel mass with respect to the mass of the moving fluid. Special comb-shaped electrodes are integrated on the channels for capacitive readout of the extremely small Coriolis displacements. The comb-shaped electrode design eliminates the need for multiple metal layers and sacrificial layer etching methods. Furthermore, it prevents squeezed film damping due to a thin layer of air between the capacitor electrodes. As a result, the sensor operates at atmospheric pressure with a quality factor in the order of 40 and does not require vacuum packaging like other micro Coriolis flow sensors. Measurement results using water, ethanol, white gas and argon are presented, showing that the sensor measures true mass flow. The measurement error is currently in the order of 1% of the full scale of 1.2 g h-1.
Characterization of Gas Flow Ability and Contribution of Diffusion to Total Mass Flux in the Shale
Directory of Open Access Journals (Sweden)
Rui Wang
2013-07-01
Full Text Available The aim of this study is to search a parameter which characterize the flow ability and analyze the contribution of diffusion to total mass flux of gas flow in pore of shale whose size is as low as nanoscale. The diffusion coefficient of the flow region which was determined by Kundsen number was taken as the diffusion coefficient of system, then it was substituted into the equation which describes gas diffusive and flow in nano-porous media, the apparent permeability and mass flux were calculated and the impacts of the pore radius and gas type were analyzed finally. The result showed that the diffusion of gas in shale was mainly in the transition diffusion or Fick diffusion region; The ratio of the apparent permeability of considering the diffusion and slippage effect to Darcy permeability and the ratio of diffusion mass flux to total mass flux increased with the decreasing of the pore radius; The diffusion ability of the methane was stronger than ethane’s. The present study implied that the calculated results of the diffusion coefficient which considers three kind of diffusion was less than that one considering Knudsen diffusion only; Considering diffusion and slippage effect, the apparent permeability of nanoscale pore of shale was 10-6 μm2 level, not 10-9 μm2 level in general temperature and pressure of shale reservoir.
Effect of Coolant Temperature and Mass Flow on Film Cooling of Turbine Blades
Garg, Vijay K.; Gaugler, Raymond E.
1997-01-01
A three-dimensional Navier Stokes code has been used to study the effect of coolant temperature, and coolant to mainstream mass flow ratio on the adiabatic effectiveness of a film-cooled turbine blade. The blade chosen is the VKI rotor with six rows of cooling holes including three rows on the shower head. The mainstream is akin to that under real engine conditions with stagnation temperature = 1900 K and stagnation pressure = 3 MPa. Generally, the adiabatic effectiveness is lower for a higher coolant temperature due to nonlinear effects via the compressibility of air. However, over the suction side of shower-head holes, the effectiveness is higher for a higher coolant temperature than that for a lower coolant temperature when the coolant to mainstream mass flow ratio is 5% or more. For a fixed coolant temperature, the effectiveness passes through a minima on the suction side of shower-head holes as the coolant to mainstream mass flow, ratio increases, while on the pressure side of shower-head holes, the effectiveness decreases with increase in coolant mass flow due to coolant jet lift-off. In all cases, the adiabatic effectiveness is highly three-dimensional.
Stolker, A.A.M.; Peters, R.J.B.; Zuiderent, R.; DiBussolo, J.M.; Martins, C.P.B.
2010-01-01
There is an increasing interest in screening methods for quick and sensitive analysis of various classes of veterinary drugs with limited sample pre-treatment. Turbulent flow chromatography in combination with tandem mass spectrometry has been applied for the first time as an efficient screening met
On computations for thermal radiation in MHD channel flow with heat and mass transfer.
Hayat, T; Awais, M; Alsaedi, A; Safdar, Ambreen
2014-01-01
This study examines the simultaneous effects of heat and mass transfer on the three-dimensional boundary layer flow of viscous fluid between two infinite parallel plates. Magnetohydrodynamic (MHD) and thermal radiation effects are present. The governing problems are first modeled and then solved by homotopy analysis method (HAM). Influence of several embedded parameters on the velocity, concentration and temperature fields are described.
Vibration Isolation by an Actively Compliantly Mounted Sensor Applied to a Coriolis Mass-Flow Meter
Ridder, van de L.; Hakvoort, W.B.J.; Dijk, van J.; Lötters, Joost C.; Boer, de A.
2016-01-01
In this paper, a vibration isolated design of a Coriolis mass-flow meter (CMFM) is proposed by introducing a compliant connection between the casing and the tube displacement sensors, with the objective to obtain a relative displacement measurement of the fluid conveying tube, dependent on the tube
Mass transfer coefficient of slug flow for organic solvent-aqueous system in a microreactor
Energy Technology Data Exchange (ETDEWEB)
Tuek, Ana Jurinjak; Anic, Iva; Kurtanjek, Zelimir; Zelic, Bruno [University of Zagreb, Zagreb (Croatia)
2015-06-15
Application of microreactor systems could be the next break-through in the intensification of chemical and biochemical processes. The common flow regime for organic solvent-aqueous phase two-phase systems is a segmented flow. Internal circulations in segments cause high mass transfer and conversion. We analyzed slug flow in seven systems of organic solvents and aqueous phase. To analyze how slug lengths in tested systems depend on linear velocity and physical and chemical properties of used organic solvents, regression models were proposed. It was shown that models based on linearization of approximation by potentials give low correlation for slug length prediction; however, application of an essential nonlinear model of multiple layer perception (MLP) neural network gives high correlation with R{sup 2}=0.9. General sensitivity analysis was applied for the MLP neural network model, which showed that 80% of variance in slug length for the both phases is accounted for the viscosity and density of the organic phases; 10% is accounted by surface tension of the organic phase, while molecular masses and flow rates each account for 5%. For defined geometry of microreactor, mass transfer has been determined by carrying out the neutralization experiment with NaOH where acetic acid diffuses from organic phase (hexane) into aqueous phase. Estimated mass transfer coefficients were in the range k{sub L}a=4,652-1,9807 h{sup -1}.
Mansour, M A; El-Kabeir, S M
2000-01-01
Steady laminar boundary layer analysis of heat and mass transfer characteristics in magnetohydrodynamic (MHD) flow of a micropolar fluid on a circular cylinder maintained at uniform heat and mass flux has been conducted. The solution of the energy equation inside the boundary layer is obtained as a power series of the distance measured along the surface from the front stagnation point of the cylinder. The results of dimensionless temperature, Nusselt number, wall shear stress, wall couple stress and Sherwood number have been presented graphically for various values of the material parameters. The results indicate that the micropolar fluids display a reduction in drag as well as heat transfer rate when compared with Newtonian fluids.
DEFF Research Database (Denmark)
Rein, Arno; Bauer, S; Dietrich, P
2009-01-01
is present, the concentration variability due to a fluctuating groundwater flow direction varies significantly within the control plane and between the different realizations. Determination of contaminant mass fluxes is also influenced by the temporal variability of the concentration measurement, especially......Monitoring of contaminant concentrations, e.g., for the estimation of mass discharge or contaminant degradation rates. often is based on point measurements at observation wells. In addition to the problem, that point measurements may not be spatially representative. a further complication may arise...... due to the temporal dynamics of groundwater flow, which may cause a concentration measurement to be not temporally representative. This paper presents results from a numerical modeling study focusing on temporal variations of the groundwater flow direction. "Measurements" are obtained from point...
Flow equations in the light-front QCD mass gap and confinement
Gubankova, E
2000-01-01
The light-front QCD is studied using the method of flow equations. Solving the light-front gluon gap equation, the effective gluon mass is generated dynamically. The effective interaction between static quark and antiquark, generated through elimination of the quark-gluon minimal coupling by flow equations, has the Coulomb, $1/q^2$, and confining, $1/q^4$, singular behavior. Elimination of the quark-gluon coupling at small gluon momenta is governed by the cutoff dependent, dynamical gluon mass, which makes this elimination possible and provides such an enhancement at $q\\sim 0$. The cutoff, which regulates small light-front $x$ divergences, sets up a scale for the dynamical gluon mass and the string tension in the $q\\bar{q}$-potential. The mechanism of confimenemet in the light-front frame is suggested, based on the singular nature of the light-front gauge along the light-front $x$-axis.
Effects of fluid recirculation on mass transfer from the arterial surface to flowing blood
Institute of Scientific and Technical Information of China (English)
Zhi-Guo Zhang; Xi-Wen Zhang; Ying-Xi Liu
2012-01-01
The effect of disturbed flow on the mass transfer from arterial surface to flowing blood was studied numerically,and the results were compared with that of our previous work.The arterial wall was assumed to be viscoelastic and the blood was assumed to be incompressible and non-Newtonian fluid,which is more close to human arterial system.Numerical results indicated that the mass transfer from the arterial surface to flowing blood in regions of disturbed flow is positively related with the wall shear rates and it is significantly enhanced in regions of disturbed flow with a local minimum around the reattachment point which is higher than the average value of the downstream.Therefore,it may be implied that the accumulation of cholesterol or lipids within atheromatous plaques is not caused by the reduced efflux of cholesterol or lipids,but by the infiltration of the LDL (low-density lipoprotein) from the flowing blood to the arterial wall.
Numerical investigation of interface region flows in mass spectrometers: neutral gas transport
Energy Technology Data Exchange (ETDEWEB)
Jugroot, Manish [Institute for Aerospace Studies, University of Toronto, 4925 Dufferin Street, Toronto, Ontario, M3H 5T6 (Canada); Groth, Clinton P T [Institute for Aerospace Studies, University of Toronto, 4925 Dufferin Street, Toronto, Ontario, M3H 5T6 (Canada); Thomson, Bruce A [MDS SCIEX, 71 Four Valley Drive, Concord, Ontario, L4K 4V8 (Canada); Baranov, Vladimir [MDS SCIEX, 71 Four Valley Drive, Concord, Ontario, L4K 4V8 (Canada); Collings, Bruce A [MDS SCIEX, 71 Four Valley Drive, Concord, Ontario, L4K 4V8 (Canada)
2004-04-21
The supersonic jet flows of neutral gas from atmospheric to near-vacuum conditions in the interface region of mass-spectrometer systems is investigated by continuum-based (fluid) numerical simulations. An enhanced understanding of the neutral gas transport is of paramount importance to fully understand flows in the interface region of mass spectrometers, for it is the neutral dynamics that governs and drives the ions from the high pressure ion source through the interface orifice towards the ion optics and detector subsystems. The key features and structure of the complex neutral gas flow are examined and the influence of large pressure differences imposed across the interface region, orifice geometry, and gas skimmer configuration used for flow control are assessed. The flow structure is shown to be that of a classical under-expanded free jet for 'skimmer-absent' cases and very good agreement between the numerical predictions and empirical and experimental values is demonstrated. For the 'skimmer-present' cases, the shock structure downstream of the orifice and skimmer is identified and fully described and its influences on the flow skimming and focusing processes are discussed.
Phase diagram distortion from traffic parameter averaging.
Stipdonk, H. Toorenburg, J. van & Postema, M.
2010-01-01
Motorway traffic congestion is a major bottleneck for economic growth. Therefore, research of traffic behaviour is carried out in many countries. Although well describing the undersaturated free flow phase as an almost straight line in a (k,q)-phase diagram, congested traffic observations and
Phase diagram distortion from traffic parameter averaging.
Stipdonk, H. Toorenburg, J. van & Postema, M.
2010-01-01
Motorway traffic congestion is a major bottleneck for economic growth. Therefore, research of traffic behaviour is carried out in many countries. Although well describing the undersaturated free flow phase as an almost straight line in a (k,q)-phase diagram, congested traffic observations and theori
Energy Technology Data Exchange (ETDEWEB)
Yoshino, Naoto; Uchida, Masahiro [Japan Nuclear Cycle Development Inst., Tokai Works, Tokai, Ibaraki (Japan); Satou, Hisashi [Inspection Development Company Ltd., Tokai, Ibaraki (Japan)
2003-03-01
The understanding of mass transport and fluid flow properties in natural rock fractures is important for safety assessment of geological disposal of high level nuclear waste. The authors developed advanced tracer test equipment in which a 50-cm cubic scale rock sample was feasible. The mass transport and fluid flow properties in a single fracture were also examined. The relation among hydraulic, transport and mass balance apertures of a natural single fracture were obtained. Heterogeneity of the aperture distribution was evident, as was the possibility of some major flow line perpendicular to the flow direction. Additionally, the relation between normal stress and each aperture was also obtained by loading normal stress on the fracture. In future, measuring the aperture distribution and establishing the model considering fluid flow and mass transport properties in natural rock fractures will be conducted. (author)
Conder, J. R.; Gunn, D. J.; Shaikh, M. A.
1982-08-01
A mathematical model is presented for the vaporisation of liquid from a laminar film flowing down the inside surface of a smooth tube into a countercurrent laminar flow of gas. The partial differential equations that describe temperature and composition distributions are integrated across the tube to give a set of four coupled ordinary differential equations. A numerical method for the solution of the equations is proposed and examined; the method is posed to solve the transient response for heat and mass transfer. A satisfactory solution is found for a range of space and time intervals. The mathematical model has been validated by experimental measurements on a falling film evaporator with evaporation occurring at sub-boiling temperatures from a laminar liquid film into a laminar gas stream. The performance of the evaporator is assessed.
Magnetic resonance imaging of flow and mass transfer in electrohydrodynamic liquid bridges
Wexler, Adam D; Fuchs, Elmar C; Woisetschläger, Jakob; Reiter, Gert; Fuchsjäger, Michael; Reiter, Ursula
2016-01-01
Here we report on the feasibility and use of magnetic resonance imaging based methods to the study of electrohydrodynamic (EHD) liquid bridges. High speed tomographic recordings through the longitudinal axis of water bridges were used to characterize the mass transfer dynamics, mixing, and flow structure. By filling one beaker with heavy water and the other with light water it was possible to track the spread of the proton signal throughout the total liquid volume. The mixing kinetics are different depending on where the light nuclei are located and proceeds faster when the anolyte is light water. Distinct flow and mixing regions are identified in the fluid volumes and it is shown that the EHD flow at the electrodes can be counteracted by the density difference between water isotopes. MR phase contrast imaging reveals that within the bridge section two separate counter propagating flows pass one above the other in the bridge.
Numerical investigation of neutral flows in the interface region of mass spectrometers
Energy Technology Data Exchange (ETDEWEB)
Jugroot, M.; Groth, C.P.T. [Univ. of Toronto, Inst. for Aerospace Studies, Toronto, Ontario (Canada)]. E-mail: jugroot@utias.utoronto.ca; groth@utias.utoronto.ca; Thomson, B.A.; Baranov, V.; Collings, B.A. [MDS SCIEX, Concord, Ontario (Canada)]. E-mail: Bruce.Thomson@sciex.com; Vladimir.Baranov@sciex.com; Bruce.Collings@sciex.com
2002-07-01
The flow of neutral gas from atmospheric to near-vacuum conditions in the interface region of a mass-spectrometer is investigated by continuum-based numerical simulations. The key features of the neutral gas flow are examined and the influence of back pressure, orifice geometry, and gas skimmer configuration are assessed. The flow structure is shown to be that of a classical under-expanded free jet for 'skimmer-absent' cases and very good agreement between the numerical predictions and empirical and experimental values is demonstrated. For the 'skimmer-present' cases, the influence of the skimmer and the flow structure downstream of the orifice and skimmer are of particular interest and are investigated and discussed. (author)
The Ionization of Accretion Flows in High Mass Star Formation: W51e2
Keto, Eric
2008-01-01
Previous observations show that the hypercompact HII region W51e2 is surrounded by a massive molecular accretion flow centered on the HII region. New observations of the H53alpha radio recombination line made with the VLA at 0.45 arc second angular resolution show a velocity gradient in the ionized gas within the HII region of > 500 kms-1 pc-1 comparable to the velocity gradient seen in the molecular accretion flow. New CO line observations made with the SMA at arc second angular resolution detect a molecular bipolar outflow immediately around the W51e2 HII region and extending along the axis of rotation of the molecular flow. These observations are consistent with an evolutionary phase for high mass star formation in which a newly formed massive star first begins to ionize its surroundings including its own accretion flow.
Directory of Open Access Journals (Sweden)
Gözde Ersöz, Ersin Altiparmak, F. Hülya Aşçı
2016-06-01
Full Text Available The purpose of this study was to examine differences in behavioral regulations, dispositional flow, social physique anxiety of exercisers in terms of body mass index (BMI. 782 university students participated in this study. Dispositional Flow State Scale-2, Behavioral Regulations in Exercise Questionnaire-2, Social Physique Anxiety Scale and Physical Activity Stages of Change Questionnaire were administered to participants. After controlling for gender, analysis indicated significant differences in behavioral regulations, dispositional flow and social physique anxiety of exercise participants with regards to BMI. In summary, the findings demonstrate that normal weighted participants exercise for internal reasons while underweighted participants are amotivated for exercise participation. Additionally, participants who are underweight had higher dispositional flow and lower social physique anxiety scores than other BMI classification.
Geometrical splitting and reduction of Feynman diagrams
Davydychev, Andrei I.
2016-10-01
A geometrical approach to the calculation of N-point Feynman diagrams is reviewed. It is shown that the geometrical splitting yields useful connections between Feynman integrals with different momenta and masses. It is demonstrated how these results can be used to reduce the number of variables in the occurring functions.
Energy Technology Data Exchange (ETDEWEB)
Neutz, Jochen; Koenig, Andreas [Fraunhofer Institut fuer Chemische Technologie ICT, Pfinztal (Germany); Knauss, Helmut; Jordan, Sebastian; Roediger, Tim; Smorodsky, Boris [Universitaet Stuttgart (Germany). Institut fuer Aerodynamik und Gasdynamik; Bluemcke, Erich Walter [AUDI AG, Department I/EK-523, Ingolstadt (Germany)
2009-06-15
The mass flow characteristics of gas generators for airbag applications have to comply with a number of requirements for an optimal deployment of the airbag itself. Up to now, the mass flow was determined from pressure time histories of so-called can tests. This procedure suffers from the missing knowledge on the temperature of the generated gas entering the can. A new test setup described in this paper could overcome this problem by providing highly time resolved information on the gas's total temperature and the mass flow of the generator. The test setup consisted of a combustion chamber with a specially designed Laval nozzle in combination with a temperature sensor of high time resolution. The results showed a high time resolved temperature signal, which was disturbed by the formation of a slag layer on the sensor. Plausibility considerations with experimentally and thermodynamically determined combustion temperatures led to satisfying results for the overall temperature as characteristic parameter of airbag inflating gases flows from pyrotechnics. (Abstract Copyright [2009], Wiley Periodicals, Inc.)
The Formal Semantics of an UML Activity Diagram
Institute of Scientific and Technical Information of China (English)
梁义芝; 王延章; 刘云飞
2004-01-01
Due to lack of strictly defined formal semantics, an UML activity diagram is unsuitable for the tasks of formal analysis, verification and assertion on the system it describes. In this paper, Petri net is used to define the formal semantics of an UML activity diagram containing object flow states, laying a foundation for the precise description and analysis of a workflow system.
Equational binary decision diagrams
Groote, J.F.; Pol, J.C. van de
2000-01-01
We incorporate equations in binary decision diagrams (BDD). The resulting objects are called EQ-BDDs. A straightforward notion of ordered EQ-BDDs (EQ-OBDD) is defined, and it is proved that each EQ-BDD is logically equivalent to an EQ-OBDD. Moreover, on EQ-OBDDs satisfiability and tautology checkin
Lindenbergh, R.C.
2002-01-01
The classic Voronoi diagram of a configuration of distinct points in the plane associates to each point that part of the plane that is closer to the point than to any other point in the configuration. In this thesis we no longer require all points to be distinct. After the introduction in
Equational binary decision diagrams
J.F. Groote (Jan Friso); J.C. van de Pol (Jaco)
2000-01-01
textabstractWe incorporate equations in binary decision diagrams (BDD). The resulting objects are called EQ-BDDs. A straightforward notion of ordered EQ-BDDs (EQ-OBDD) is defined, and it is proved that each EQ-BDD is logically equivalent to an EQ-OBDD. Moreover, on EQ-OBDDs satisfiability and
Compressing Binary Decision Diagrams
DEFF Research Database (Denmark)
Hansen, Esben Rune; Satti, Srinivasa Rao; Tiedemann, Peter
2008-01-01
The paper introduces a new technique for compressing Binary Decision Diagrams in those cases where random access is not required. Using this technique, compression and decompression can be done in linear time in the size of the BDD and compression will in many cases reduce the size of the BDD to 1...
Compressing Binary Decision Diagrams
DEFF Research Database (Denmark)
Rune Hansen, Esben; Srinivasa Rao, S.; Tiedemann, Peter
The paper introduces a new technique for compressing Binary Decision Diagrams in those cases where random access is not required. Using this technique, compression and decompression can be done in linear time in the size of the BDD and compression will in many cases reduce the size of the BDD to 1...
Kneupper, Charles W.
1978-01-01
Responds to Charles Willard's recommendations (in an article in "Communication Monographs," November 1976) that argument be viewed as an attempt to establish formal relationships among symbolic structures. Demonstrates flaws in this redefinition and shows argument diagrams to be theoretically and practically justifiable. (JMF)
Compressing Binary Decision Diagrams
DEFF Research Database (Denmark)
Hansen, Esben Rune; Satti, Srinivasa Rao; Tiedemann, Peter
2008-01-01
The paper introduces a new technique for compressing Binary Decision Diagrams in those cases where random access is not required. Using this technique, compression and decompression can be done in linear time in the size of the BDD and compression will in many cases reduce the size of the BDD to 1...
Equational binary decision diagrams
J.F. Groote (Jan Friso); J.C. van de Pol (Jaco)
2000-01-01
textabstractWe incorporate equations in binary decision diagrams (BDD). The resulting objects are called EQ-BDDs. A straightforward notion of ordered EQ-BDDs (EQ-OBDD) is defined, and it is proved that each EQ-BDD is logically equivalent to an EQ-OBDD. Moreover, on EQ-OBDDs satisfiability and tauto
Results of the evaluation and preliminary validation of a primary LNG mass flow standard
van der Beek, Mijndert; Lucas, Peter; Kerkhof, Oswin; Mirzaei, Maria; Blom, Gerard
2014-10-01
LNG custody transfer measurements at large terminals have been based on ship tank level gauging for more than 50 years. Flow meter application has mainly been limited to process control in spite of the promise of simplified operations, potentially smaller uncertainties and better control over the measurements for buyers. The reason for this has been the lack of LNG flow calibration standards as well as written standards. In the framework of the EMRP1 ‘Metrology for LNG’ project, Van Swinden Laboratory (VSL) has developed a primary LNG mass flow standard. This standard is so far the only one in the world except for a liquid nitrogen flow standard at the National Institute of Standards and Technology (NIST). The VSL standard is based on weighing and holds a Calibration and Measurement Capability (CMC) of 0.12% to 0.15%. This paper discusses the measurement principle, results of the uncertainty validation with LNG and the differences between water and LNG calibration results of four Coriolis mass flow meters. Most of the calibrated meters do not comply with their respective accuracy claims. Recommendations for further improvement of the measurement uncertainty will also be discussed.
Predictions of the marviken subcooled critical mass flux using the critical flow scaling parameters
Energy Technology Data Exchange (ETDEWEB)
Park, Choon Kyung; Chun, Se Young; Cho, Seok; Yang, Sun Ku; Chung, Moon Ki [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)
1997-12-31
A total of 386 critical flow data points from 19 runs of 27 runs in the Marviken Test were selected and compared with the predictions by the correlations based on the critical flow scaling parameters. The results show that the critical mass flux in the very large diameter pipe can be also characterized by two scaling parameters such as discharge coefficient and dimensionless subcooling (C{sub d,ref} and {Delta}{Tau}{sup *} {sub sub}). The agreement between the measured data and the predictions are excellent. 8 refs., 8 figs. 1 tab. (Author)
Mass flow rate of granular material in silos with lateral exit holes
Medina, Abraham; Serrano, Armando; Sanchez, Florencio
2014-11-01
In this work we have analyzed experimentally the mass flow rate, m', of the lateral outflow of cohesionless granular material through circular orifices of diameter D and rectangular and triangular slots of hydraulic diameter DH made in vertical walls of bins. Experiments were made in order to determine also the influence of the wall thickness of the bin, w. Geometrical and physical arguments, are given to get a general correlation for m' embracing both quantities, D (DH) and w. The angle of repose is also an important factor characterizing these flows.
Pacific Basin tsunami hazards associated with mass flows in the Aleutian arc of Alaska
Waythomas, Christopher F.; Watts, Philip; Shi, Fengyan; Kirby, James T.
2009-01-01
We analyze mass-flow tsunami generation for selected areas within the Aleutian arc of Alaska using results from numerical simulation of hypothetical but plausible mass-flow sources such as submarine landslides and volcanic debris avalanches. The Aleutian arc consists of a chain of volcanic mountains, volcanic islands, and submarine canyons, surrounded by a low-relief continental shelf above about 1000–2000 m water depth. Parts of the arc are fragmented into a series of fault-bounded blocks, tens to hundreds of kilometers in length, and separated from one another by distinctive fault-controlled canyons that are roughly normal to the arc axis. The canyons are natural regions for the accumulation and conveyance of sediment derived from glacial and volcanic processes. The volcanic islands in the region include a number of historically active volcanoes and some possess geological evidence for large-scale sector collapse into the sea. Large scale mass-flow deposits have not been mapped on the seafloor south of the Aleutian Islands, in part because most of the area has never been examined at the resolution required to identify such features, and in part because of the complex nature of erosional and depositional processes. Extensive submarine landslide deposits and debris flows are known on the north side of the arc and are common in similar settings elsewhere and thus they likely exist on the trench slope south of the Aleutian Islands. Because the Aleutian arc is surrounded by deep, open ocean, mass flows of unconsolidated debris that originate either as submarine landslides or as volcanic debris avalanches entering the sea may be potential tsunami sources. To test this hypothesis we present a series of numerical simulations of submarine mass-flow initiated tsunamis from eight different source areas. We consider four submarine mass flows originating in submarine canyons and four flows that evolve from submarine landslides on the trench slope. The flows have lengths
Visualization design and verification of Ada tasking using timing diagrams
Vidale, R. F.; Szulewski, P. A.; Weiss, J. B.
1986-01-01
The use of timing diagrams is recommended in the design and testing of multi-task Ada programs. By displaying the task states vs. time, timing diagrams can portray the simultaneous threads of data flow and control which characterize tasking programs. This description of the system's dynamic behavior from conception to testing is a necessary adjunct to other graphical techniques, such as structure charts, which essentially give a static view of the system. A series of steps is recommended which incorporates timing diagrams into the design process. Finally, a description is provided of a prototype Ada Execution Analyzer (AEA) which automates the production of timing diagrams from VAX/Ada debugger output.
Energy Technology Data Exchange (ETDEWEB)
Salmon, R.; Edwards, M.S.; Ulrich, W.C.
1977-06-01
This volume consists of individual block flowsheets for the various units of the Synthoil facility, showing the overall flows into and out of each unit. Material balances for the following units are incomplete because these are proprietary processes and the information was not provided by the respective vendors: Unit 24-Claus Sulfur Plant; Unit 25-Oxygen Plant; Unit 27-Sulfur Plant (Redox Type); and Unit 28-Sour Water Stripper and Ammonia Recovery Plant. The process information in this form was specifically requested by ERDA/FE for inclusion in the final report.
Dindore, V. Y.; Versteeg, G. F.
2005-01-01
The cross-flow operation of hollow fiber membrane contactors offers many advantages and is preferred over the parallel-flow contactors for gas-liquid mass transfer operations. However, the analysis of such a cross-flow membrane gas-liquid contactor is complicated due to the change in concentrations
Ford, C. L.; Winroth, M.; Alfredsson, P. H.
2016-08-01
An entirely pressure-based vortex-shedding meter has been designed for use in practical time-dependent flows. The meter is capable of measuring mass-flow rate in variable density gases in spite of the fact that fluid temperature is not directly measured. Unlike other vortex meters, a pressure based meter is incredibly robust and may be used in industrial type flows; an environment wholly unsuitable for hot-wires for example. The meter has been tested in a number of static and dynamic flow cases, across a range of mass-flow rates and pressures. The accuracy of the meter is typically better than about 3% in a static flow and resolves the fluctuating mass-flow with an accuracy that is better than or equivalent to a hot-wire method.
Computer recognition of slag property diagrams in ternary systems
Institute of Scientific and Technical Information of China (English)
Jinxiong Lu; Li Wang; Jiongming Zhang; Xinhua Wang
2004-01-01
In order to take data information from the slag property diagram in a ternary system automatically and actually, a picture recognition and drawing software has been developed by Visual Basic 6.0 based on the image coding principle of computer system and the graphics programming method of VB. This software can transform the ternary system isopleth diagram from bitmap format to data file and establish a corresponding database which can be applied to rapidly retrieve a mass of data and make correlative thermodynamics or kinetics calculation. Besides, it still has the function of drawing the ternary system diagram which can draw different kinds of property parameters in the same diagram.
Phase diagram of a single lane roundabout
Echab, H.; Lakouari, N.; Ez-Zahraouy, H.; Benyoussef, A.
2016-03-01
Using the cellular automata model, we numerically study the traffic dynamic in a single lane roundabout system of four entry/exit points. The boundaries are controlled by the injecting rates α1, α2 and the extracting rate β. Both the system with and without Splitter Islands of width Lsp are considered. The phase diagram in the (α1 , β) space and its variation with the roundabout size, Pagg (i.e. the probability of aggressive entry), and Pexit (i.e. the probability of preferential exit) are constructed. The results show that the phase diagram in both cases consists of three phases: free flow, congested and jammed. However, as Lsp increases the free flow phase enlarges while the congested and jammed ones shrink. On the other hand, the short sized roundabout shows better performance in the free flow phase while the large one is more optimal in the congested phase. The density profiles are also investigated.
Peltier Effect Applied to the Design and Realization of a New Mass Flow Sensor
Rahmoun, M.; El Hassani, A.; Leclerq, D.; Bendada, E.
2000-01-01
The present paper deals with design and realization of a new mass flow sensor using the Peltier effect. The sensor, shaped as a bimetallic circuit includes two continuous parallel strips coated with a great deal of metal plated spots. In such a device, one track performs as a classical thermoelectrical circuitry whose both plated and uncoated parts provide the thermopile junctions. The other strip is subjected to electrical current so as to generate numerous small thermal gradients owing to t...
Supersonic Mass Flux Measurements via Tunable Diode Laser Absorption and Non-Uniform Flow Modeling
Chang, Leyen S.; Strand, Christopher L.; Jeffries, Jay B.; Hanson, Ronald K.; Diskin, Glenn S.; Gaffney, Richard L.; Capriotti, Diego P.
2011-01-01
Measurements of mass flux are obtained in a vitiated supersonic ground test facility using a sensor based on line-of-sight (LOS) diode laser absorption of water vapor. Mass flux is determined from the product of measured velocity and density. The relative Doppler shift of an absorption transition for beams directed upstream and downstream in the flow is used to measure velocity. Temperature is determined from the ratio of absorption signals of two transitions (lambda(sub 1)=1349 nm and lambda(sub 2)=1341.5 nm) and is coupled with a facility pressure measurement to obtain density. The sensor exploits wavelength-modulation spectroscopy with second-harmonic detection (WMS-2f) for large signal-to-noise ratios and normalization with the 1f signal for rejection of non-absorption related transmission fluctuations. The sensor line-of-sight is translated both vertically and horizontally across the test section for spatially-resolved measurements. Time-resolved measurements of mass flux are used to assess the stability of flow conditions produced by the facility. Measurements of mass flux are within 1.5% of the value obtained using a facility predictive code. The distortion of the WMS lineshape caused by boundary layers along the laser line-of-sight is examined and the subsequent effect on the measured velocity is discussed. A method for correcting measured velocities for flow non-uniformities is introduced and application of this correction brings measured velocities within 4 m/s of the predicted value in a 1630 m/s flow.
Energy Technology Data Exchange (ETDEWEB)
1980-09-01
Nineteen papers were presented at the workshop on modeling thermohydrologic flow in fractured masses. This workshop was a result of the interest currently being given to the isolation of nuclear wastes in geologic formations. Included in these proceedings are eighteen of the presentations, one abstract and summaries of the panel discussions. The papers are listed under the following categories: introduction; overviews; fracture modelings; repository studies; geothermal models; and recent developments. Eighteen of the papers have been abstracted and indexed.
Roverato, M.
2016-07-01
The present contribution documents the extremely well-preserved Paleoproterozoic architecture of the Montesbelos breccia (named here for the first time), which is interpreted as a rare example of a subaerial paleoproterozoic (>1.85 Ga) granular-dominated mass-flow deposit, few of which are recorded in the literature. Montesbelos deposit is part of the andesitic Sobreiro Formation located in the São Felix do Xingu region, southern Amazonian craton, northern Brazil. The large volume, high variability of textural features, presence of broken clasts, angular low sphericity fragments, mono- to heterolithic character, and the size of the outcrops point to a volcanic debris avalanche flow. Fluviatile sandy material and debris flows are associated with the deposit as a result of post-depositional reworking processes.
Simulation of rarefied gas flows in atmospheric pressure interfaces for mass spectrometry systems.
Garimella, Sandilya; Zhou, Xiaoyu; Ouyang, Zheng
2013-12-01
The understanding of the gas dynamics of the atmospheric pressure interface is very important for the development of mass spectrometry systems with high sensitivity. While the gas flows at high pressure (>1 Torr) and low pressure (pressure stage (1 to 10(-3) Torr) remains challenging. In this study, we used the direct simulation Monte Carlo (DMSC) method to develop the gas dynamic simulations for the continuous and discontinuous atmospheric pressure interfaces (API), with different focuses on the ion transfer by gas flows through a skimmer or directly from the atmospheric pressure to a vacuum stage, respectively. The impacts by the skimmer location in the continuous API and the temporal evolvement of the gas flow with a discontinuous API were characterized, which provide a solid base for the instrument design and performance improvement.
Simulation of the flow and mass transfer for KDP crystals undergoing 2D translation during growth
Zhou, Chuan; Li, Mingwei; Hu, Zhitao; Yin, Huawei; Wang, Bangguo; Cui, Qidong
2016-09-01
In this study, a novel motion mode for crystals during growth, i.e., 2D translation, is proposed. Numerical simulations of flow and mass transfer are conducted for the growth of large-scale potassium dihydrogen phosphate (KDP) crystals subjected to the new motion mode. Surface supersaturation and shear stress are obtained as functions of the translational velocity, distance, size, orientation of crystals. The dependence of these two parameters on the flow fields around the crystals is also discussed. The thicknesses of the solute boundary layer varied with translational velocity are described. The characteristics of solution flow and surface supersaturation distribution are summarized, where it suggests that the morphological stability of a crystal surface can be enhanced if the proposed 2D translation is applied to crystal growth.
Viscosity parameter in dissipative accretion flows with mass outflow around black holes
Nagarkoti, Shreeram; Chakrabarti, Sandip K.
2016-10-01
Numerical hydrodynamic simulation of inviscid and viscous flows have shown that significant outflows could be produced from the CENtrifugal pressure-supported BOundary Layer or CENBOL of an advective disc. However, this barrier is weakened in presence of viscosity, more so, if there are explicit energy dissipations at the boundary layer itself. We study effects of viscosity and energy dissipation theoretically on the outflow rate and show that, as the viscosity or energy dissipation (or both) rises, the prospect of formation of outflows is greatly reduced, thereby verifying results obtained through observations and numerical simulations. Indeed, we find that in a dissipative viscous flow, shocks in presence of outflows can be produced only if the Shakura-Sunyaev viscosity parameter α is less than 0.2. This is a direct consequence of modification of the Rankine-Hugoniot relation across the shock in a viscous flow, when the energy dissipation and mass-loss in the form of outflows from the post-shock region are included. If we ignore the effects of mass-loss altogether, the standing dissipative shocks in viscous flows may occur only if α black hole candidates such as GX399-4, MAXI J1659-152 and MAXI J1836-194 and find that required α are indeed well within our prescribed limit.
Air flow assisted ionization for remote sampling of ambient mass spectrometry and its application.
He, Jiuming; Tang, Fei; Luo, Zhigang; Chen, Yi; Xu, Jing; Zhang, Ruiping; Wang, Xiaohao; Abliz, Zeper
2011-04-15
Ambient ionization methods are an important research area in mass spectrometry (MS) analysis. Under ambient conditions, the gas flow and atmospheric pressure significantly affect the transfer and focusing of ions. The design and implementation of air flow assisted ionization (AFAI) as a novel and effective, remote sampling method for ambient mass spectrometry are described herein. AFAI benefits from a high extracting air flow rate. A systematic investigation of the extracting air flow in the AFAI system has been carried out, and it has been demonstrated not only that it plays a role in the effective capture and remote transport of charged droplets, but also that it promotes desolvation and ion formation, and even prevents ion fragmentation during the ionization process. Moreover, the sensitivity of remote sampling ambient MS analysis was improved significantly by the AFAI method. Highly polar and nonpolar molecules, including dyes, pharmaceutical samples, explosives, drugs of abuse, protein and volatile compounds, have been successfully analyzed using AFAI-MS. The successful application of the technique to residue detection on fingers, large object analysis and remote monitoring in real time indicates its potential for the analysis of a variety of samples, especially large objects. The ability to couple this technique with most commercially available MS instruments with an API interface further enhances its broad applicability.
Implementation of the Fissile Mass Flow Monitor Source Verification and Confirmation
Energy Technology Data Exchange (ETDEWEB)
Uckan, Taner [ORNL; March-Leuba, Jose A [ORNL; Powell, Danny H [ORNL; Nelson, Dennis [Sandia National Laboratories (SNL); Radev, Radoslav [Lawrence Livermore National Laboratory (LLNL)
2007-12-01
This report presents the verification procedure for neutron sources installed in U.S. Department of Energy equipment used to measure fissile material flow. The Fissile Mass Flow Monitor (FMFM) equipment determines the {sup 235}U fissile mass flow of UF{sub 6} gas streams by using {sup 252}Cf neutron sources for fission activation of the UF{sub 6} gas and by measuring the fission products in the flow. The {sup 252}Cf sources in each FMFM are typically replaced every 2 to 3 years due to their relatively short half-life ({approx} 2.65 years). During installation of the new FMFM sources, the source identity and neutronic characteristics provided by the manufacturer are verified with the following equipment: (1) a remote-control video television (RCTV) camera monitoring system is used to confirm the source identity, and (2) a neutron detection system (NDS) is used for source-strength confirmation. Use of the RCTV and NDS permits remote monitoring of the source replacement process and eliminates unnecessary radiation exposure. The RCTV, NDS, and the confirmation process are described in detail in this report.
DEFF Research Database (Denmark)
Andersen, Henrik Reif; Hulgaard, Henrik
2002-01-01
This paper presents a new data structure called boolean expression diagrams (BEDs) for representing and manipulating Boolean functions. BEDs are a generalization of binary decision diagrams (BDDs) which can represent any Boolean circuit in linear space. Two algorithms are described for transforming...... a BED into a reduced ordered BDD. One is a generalized version of the BDD apply-operator while the other can exploit the structural information of the Boolean expression. This ability is demonstrated by verifying that two different circuit implementations of a 16-bit multiplier implement the same...... Boolean function. Using BEDs, this verification problem is solved efficiently, while using standard BDD techniques this problem is infeasible. Generally, BEDs are useful in applications, for example tautology checking, where the end-result as a reduced ordered BDD is small. Moreover, using operators...
DEFF Research Database (Denmark)
Andersen, Henrik Reif; Hulgaard, Henrik
1997-01-01
This paper presents a new data structure called Boolean Expression Diagrams (BEDs) for representing and manipulating Boolean functions. BEDs are a generalization of Binary Decision Diagrams (BDDs) which can represent any Boolean circuit in linear space and still maintain many of the desirable...... properties of BDDs. Two algorithms are described for transforming a BED into a reduced ordered BDD. One closely mimics the BDD apply-operator while the other can exploit the structural information of the Boolean expression. The efficacy of the BED representation is demonstrated by verifying...... that the redundant and non-redundant versions of the ISCAS 85 benchmark circuits are identical. In particular, it is verified that the two 16-bit multiplication circuits (c6288 and c6288nr) implement the same Boolean functions. Using BEDs, this verification problem is solved in less than a second, while using...
DEFF Research Database (Denmark)
Øhrstrøm, Peter
2011-01-01
Some very good arguments can be given in favor of the Augustinean wisdom, according to which it is impossible to provide a satisfactory definition of the concept of time. However, even in the absence of a proper definition, it is possible to deal with conceptual problems regarding time. It can...... be done in terms of analogies and metaphors. In particular, it is attractive to make use of Peirce's diagrams by means of which various kinds of conceptual experimentation can be carried out. This paper investigates how Peircean diagrams can be used within the study of time. In particular, we discuss 1......) the topological properties of time, 2) the implicative structure in tense logic, 3) the notions of open future and branching time models, and finally 4) tenselogical alternatives to branching time models....
Comparison of clustering methods for high-dimensional single-cell flow and mass cytometry data.
Weber, Lukas M; Robinson, Mark D
2016-12-01
Recent technological developments in high-dimensional flow cytometry and mass cytometry (CyTOF) have made it possible to detect expression levels of dozens of protein markers in thousands of cells per second, allowing cell populations to be characterized in unprecedented detail. Traditional data analysis by "manual gating" can be inefficient and unreliable in these high-dimensional settings, which has led to the development of a large number of automated analysis methods. Methods designed for unsupervised analysis use specialized clustering algorithms to detect and define cell populations for further downstream analysis. Here, we have performed an up-to-date, extensible performance comparison of clustering methods for high-dimensional flow and mass cytometry data. We evaluated methods using several publicly available data sets from experiments in immunology, containing both major and rare cell populations, with cell population identities from expert manual gating as the reference standard. Several methods performed well, including FlowSOM, X-shift, PhenoGraph, Rclusterpp, and flowMeans. Among these, FlowSOM had extremely fast runtimes, making this method well-suited for interactive, exploratory analysis of large, high-dimensional data sets on a standard laptop or desktop computer. These results extend previously published comparisons by focusing on high-dimensional data and including new methods developed for CyTOF data. R scripts to reproduce all analyses are available from GitHub (https://github.com/lmweber/cytometry-clustering-comparison), and pre-processed data files are available from FlowRepository (FR-FCM-ZZPH), allowing our comparisons to be extended to include new clustering methods and reference data sets. © 2016 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of ISAC.
Energy Technology Data Exchange (ETDEWEB)
Rudin, M.J. [Univ. of Nevada, Las Vegas NV (United States); O`Brien, M.C. [Univ. of Arizona, Tucson, AZ (United States)
1995-04-01
A planning and management tool was developed that relates environmental restoration and waste management problems to technologies that can be used to remediate these problems. Although the Technology Logic Diagram has been widely used within the US Department of Energy`s Office of Environmental Restoration and Waste Management, it can be modified for use during the planning of any waste management and environmental cleanup effort.
Finite element modeling of mass transport in high-Péclet cardiovascular flows
Hansen, Kirk; Arzani, Amirhossein; Shadden, Shawn
2016-11-01
Mass transport plays an important role in many important cardiovascular processes, including thrombus formation and atherosclerosis. These mass transport problems are characterized by Péclet numbers of up to 108, leading to several numerical difficulties. The presence of thin near-wall concentration boundary layers requires very fine mesh resolution in these regions, while large concentration gradients within the flow cause numerical stabilization issues. In this work, we will discuss some guidelines for solving mass transport problems in cardiovascular flows using a stabilized Galerkin finite element method. First, we perform mesh convergence studies in a series of idealized and patient-specific geometries to determine the required near-wall mesh resolution for these types of problems, using both first- and second-order tetrahedral finite elements. Second, we investigate the use of several boundary condition types at outflow boundaries where backflow during some parts of the cardiac cycle can lead to convergence issues. Finally, we evaluate the effect of reducing Péclet number by increasing mass diffusivity as has been proposed by some researchers. This work was supported by the NSF GRFP and NSF Career Award #1354541.
Energy balance and mass conservation in reduced order models of fluid flows
Mohebujjaman, Muhammad; Rebholz, Leo G.; Xie, Xuping; Iliescu, Traian
2017-10-01
In this paper, we investigate theoretically and computationally the conservation properties of reduced order models (ROMs) for fluid flows. Specifically, we investigate whether the ROMs satisfy the same (or similar) energy balance and mass conservation as those satisfied by the Navier-Stokes equations. All of our theoretical findings are illustrated and tested in numerical simulations of a 2D flow past a circular cylinder at a Reynolds number Re = 100. First, we investigate the ROM energy balance. We show that using the snapshot average for the centering trajectory (which is a popular treatment of nonhomogeneous boundary conditions in ROMs) yields an incorrect energy balance. Then, we propose a new approach, in which we replace the snapshot average with the Stokes extension. Theoretically, the Stokes extension produces an accurate energy balance. Numerically, the Stokes extension yields more accurate results than the standard snapshot average, especially for longer time intervals. Our second contribution centers around ROM mass conservation. We consider ROMs created using two types of finite elements: the standard Taylor-Hood (TH) element, which satisfies the mass conservation weakly, and the Scott-Vogelius (SV) element, which satisfies the mass conservation pointwise. Theoretically, the error estimates for the SV-ROM are sharper than those for the TH-ROM. Numerically, the SV-ROM yields significantly more accurate results, especially for coarser meshes and longer time intervals.
The Flow and Heat and Mass Transfer on a Twisted and Fluted Tube
Conlisk, A. T.; Mei, Ning
1999-11-01
Absorption heat pumps often employ falling liquid films to transfer heat and mass both to and from the liquid. Generally, smooth vertical tubes are not efficient enough to provide the required amount of heat and mass transfer and more complex tube geometries must be used. In this paper we extend the work of Conlisk (AIChE Journal, Vol. 40, no. 5, 1994) for a vertical fluted tube to the case of a vertically twisted tube in which the flow channels are inclined at a fixed angle to the gravity vector. We consider single-component condensation and evaporation as well as binary absorption and desorption of a LiBr-water mixture. In certain parameter regimes, the equations governing the flow field and the heat and mass transfer may be solved in closed form. The film profile is shown to driven by surface tension which drives fluid into the grooves, thus thinning the film on the crests of the flutes. Results for the twisted tube are compared with the vertically fluted tube and with the smooth tube in terms of heat and mass transfer rates.
The Massive Thermal Basketball Diagram
Andersen, J O; Strickland, Michael T; Andersen, Jens O.; Braaten, Eric; Strickland, Michael
2000-01-01
The "basketball diagram" is a three-loop vacuum diagram for a scalar fieldtheory that cannot be expressed in terms of one-loop diagrams. We calculatethis diagram for a massive scalar field at nonzero temperature, reducing it toexpressions involving three-dimensional integrals that can be easily evaluatednumerically. We use this result to calculate the free energy for a massivescalar field with a phi^4 interaction to three-loop order.
Feynman diagram drawing made easy
Baillargeon, Marc; Nogueira, P.
1997-02-01
We present a drawing package optimised for Feynman diagrams. These can be constructed interactively with a mouse-driven graphical interface or from a script file, more suitable to work with a diagram generator. It provides most features encountered in Feynman diagrams and allows to modify every part of a diagram after its creation. Special attention has been paid to obtain a high quality printout as easily as possible. This package is written in Tcl/Tk and in C.
Yu, Huidan; Chen, Xi; Wang, Zhiqiang; Deep, Debanjan; Lima, Everton; Zhao, Ye; Teague, Shawn D
2014-06-01
In this paper, we develop a mass-conserved volumetric lattice Boltzmann method (MCVLBM) for numerically solving fluid dynamics with willfully moving arbitrary boundaries. In MCVLBM, fluid particles are uniformly distributed in lattice cells and the lattice Boltzmann equations deal with the time evolution of the particle distribution function. By introducing a volumetric parameter P(x,y,z,t) defined as the occupation of solid volume in the cell, we distinguish three types of lattice cells in the simulation domain: solid cell (pure solid occupation, P=1), fluid cell (pure fluid occupation, P=0), and boundary cell (partial solid and partial fluid, 0Boltzmann equations are self-regularized through P and consist of three parts: (1) collision taking into account the momentum exchange between the willfully moving boundary and the flow; (2) streaming accompanying a volumetric bounce-back procedure in boundary cells; and (3) boundary-induced volumetric fluid migration moving the residual fluid particles into the flow domain when the boundary swipes over a boundary cell toward a solid cell. The MCVLBM strictly satisfies mass conservation and can handle irregular boundary orientation and motion with respect to the mesh. Validation studies are carried out in four cases. The first is to simulate fluid dynamics in syringes focusing on how MCVLBM captures the underlying physics of flow driven by a willfully moving piston. The second and third cases are two-dimensional (2D) peristaltic flow and three-dimensional (3D) pipe flow, respectively. In each case, we compare the MCVLBM simulation result with the analytical solution and achieve quantitatively good agreements. The fourth case is to simulate blood flow in human aortic arteries with a very complicated irregular boundary. We study steady flow in two dimensions and unsteady flow via the pulsation of the cardiac cycle in three dimensions. In the 2D case, both vector (velocity) and scalar (pressure) fields are compared to
Material flow of production process
Directory of Open Access Journals (Sweden)
Hanzelová Marcela
2001-12-01
Full Text Available This paper deals with material flow of the production process. We present the block diagram of material flow and capacities of engine in various plants each other. In this paper is used IPO (Input Process Output diagram. IPO diagram described process with aspect to input and output. Production program regards string of precision, branch and paralel processes with aspect IPO diagram.Process is not important with aspect to events. We are looking on the process as a black box. For process is used different materials and raw materials. The foudation for material analysis is detailed model of production process with defined flow material, energy, waste etc.Material flow is organised move of mass (material, money, informations, people etc.. Material analysis is made against destination of material flow (i.e. from ending to beginning. Material analysis is performed on the detection demand of individual materials, stocks, forms, etc.For elementary materials and raw materials in which is based production program and which to create better part of production costs is mainly necessary to dedicate the remark. The fluency of material flow concentrates on the respect of the capacitive parameters for individual node from aspect to standardized qualitative parameters and allowed limits.
Voronoi diagrams on the sphere
Na, H.-S.; Lee, C.-N.; Cheong, O.
2001-01-01
Given a set of compact sites on a sphere, we show that their spherical Voronoi diagram can be computed by computing two planar Voronoi diagrams of suitably transformed sites in the plane. We also show that a planar furthest-site Voronoi diagram can always be obtained as a portion of a
Directory of Open Access Journals (Sweden)
Yuni Cintia Yuze
2016-11-01
Full Text Available The importance of information and the possible risk of disruption, therefore the universities need to designed and implemented of the information security. One of the standards that can be used to analyze the level of information security in the organization is ISO/IEC 27001 : 2013 and this standard has been prepared to provide requirements for establishing, implementing, maintaining and continually improving an information security management system. The objective of this research is to measure the level of information security based on standard ISO/IEC 27001: 2013 and modeling systems for information security management. This research uses descriptive qualitative approach, data collection and validation techniques with tringulasi (interview, observation and documentation. Data was analyzed using gap analysis and to measure the level of maturity this research uses SSE-CMM (Systems Security Engineering Capability Maturity Model. Based on the research results, Maturity level clause Information Security Policy reaches level 1 (Performed-Informally, clause Asset Management reaches level 3 (Well-Defined, clause Access Control reaches level 3 (Well-Defined, clause Physical and Environmental Security reaches level 3 (Well-Defined, clause Operational Security reaches level 3 (Well-Defined, Communication Security clause reaches the level 2 (Planned and Tracked. Based on the results of maturity level discovery of some weakness in asset management in implementing the policy. Therefore, the modeling system using the flow map and CD / DFD focused on Asset Management System.
Does the butterfly diagram indicate asolar flux-transport dynamo?
Schüssler, M
2004-01-01
We address the question whether the properties of the observed latitude-time diagram of sunspot occurence (the butterfly diagram) provide evidence for the operation of a flux-transport dynamo, which explains the migration of the sunspot zones and the period of the solar cycle in terms of a deep equatorward meridional flow. We show that the properties of the butterfly diagram are equally well reproduced by a conventional dynamo model with migrating dynamo waves, but without transport of magnetic flux by a flow. These properties seem to be generic for an oscillatory and migratory field of dipole parity and thus do not permit an observational distinction between different dynamo approaches.
Directory of Open Access Journals (Sweden)
Shih-Cheng Hu
2016-12-01
Full Text Available A mathematical model is developed using the Matlab/Simulink platform to investigate heat and mass transfer performance of cross-flow and counterflow dehumidifiers with Lithium Chloride (LiCl solution. In the liquid desiccant dehumidifier, the orthogonal polynomial basis is used to simulate the combined processes of heat and mass transfer. The temperature profiles on cross-flow and countercurrent flow dehumidifiers are demonstrated. The resultant counter flow air changes the temperature profile of the LiCl solution in the longitudinal direction because of the drag forces. In addition, when inlet airflow rate reaches 15 kg·s−1, the temperature effect becomes less obvious and may be reasonably negligible. Under these conditions, the air changes the design factor and determines the interfacial temperature. It is demonstrated that the mathematical model can be of great value in the design and improvement of cross-flow and countercurrent flow dehumidifiers.
Helsper, J.P.F.G.; Peters, R.J.B.; Bemmel, M.E.M. van; Rivera, Z.E.H.; Wagner, S.; Kammer, F. von der; Tromp, P.C.; Hofmann, T.; Weigel, S.
2016-01-01
Seven commercial titanium dioxide pigments and two other well-defined TiO2 materials (TiMs) were physicochemically characterised using asymmetric flow field flow fractionation (aF4) for separation, various techniques to determine size distribution and inductively coupled plasma mass spectrometry (IC
Surface coating thickness and aggregation state have strong influence on the environmental fate, transport, and toxicity of engineered nanomaterials. In this study, flow-field flow fractionation coupled on-line with single particle inductively coupled plasma-mass spectrometry i...
Qureshi, R.N.; Kaal, E.; Janssen, H.-G.; Schoenmakers, P.J.; Kok, W.Th.
2011-01-01
Asymmetric flow field flow fractionation (AsFlFFF) was combined with pyrolysis-gas chromatography mass spectrometry for a sized based fractionation and a detailed compositional study of the triglycerides and cholesterol associated with the various lipoprotein subclasses present in human serum. Serum
Ersöz, Gözde; Altiparmak, Ersin; Aşçı, F Hülya
2016-06-01
The purpose of this study was to examine differences in behavioral regulations, dispositional flow, social physique anxiety of exercisers in terms of body mass index (BMI). 782 university students participated in this study. Dispositional Flow State Scale-2, Behavioral Regulations in Exercise Questionnaire-2, Social Physique Anxiety Scale and Physical Activity Stages of Change Questionnaire were administered to participants. After controlling for gender, analysis indicated significant differences in behavioral regulations, dispositional flow and social physique anxiety of exercise participants with regards to BMI. In summary, the findings demonstrate that normal weighted participants exercise for internal reasons while underweighted participants are amotivated for exercise participation. Additionally, participants who are underweight had higher dispositional flow and lower social physique anxiety scores than other BMI classification. Key pointsNormal weighted participants exercise for internal reasons.Underweighted participants are amotivated for exercise participation.Underweighted participants had higher dispositional flow.Underweighted participants have lower social physique anxiety scores than normal weighted, overweight and obese participants.
Investigation of transonic flow over segmented slotted wind tunnel wall with mass transfer
Bhat, M. K.; Vakili, A. D.; Wu, J. M.
1990-01-01
The flowfield on a segmented multi-slotted wind tunnel wall was studied at transonic speeds by measurements in and near the wall layer using five port cone probes. The slotted wall flowfield was observed to be three-dimensional in nature for a relatively significant distance above the slot. The boundary layer characteristics measured on the single slotted wall were found to be very sensitive to the applied suction through the slot. The perturbation in the velocity components generated due to the flow through the slot decay rapidly in the transverse direction. A vortex-like flow existed on the single slotted wall for natural ventilation but diminished with increased suction flow rate. For flow on a segmented multi-slotted wall, the normal velocity component changes were found to be maximum for measurement points located between the segmented slots atop the active chamber. The lateral influence due to applied suction and blowing, through a compartment, exceeded only slightly that in the downstream direction. Limited upstream influence was observed. Influence coefficients were determined from the data in the least-square sense for blowing and suction applied through one and two compartments. This was found to be an adequate determination of the influence coefficients for the range of mass flows considered.
Elliptic flow of ϕ mesons at intermediate pT: Influence of mass versus quark number
Choudhury, Subikash; Sarkar, Debojit; Chattopadhyay, Subhasis
2017-02-01
We have studied elliptic flow (v2) of ϕ mesons in the framework of a multiphase transport (AMPT) model at CERN Large Hadron Collider (LHC) energy. In the realms of AMPT model we observe that ϕ mesons at intermediate transverse momentum (pT) deviate from the previously observed [at the BNL Relativistic Heavy Ion Collider (RHIC)] particle type grouping of v2 according to the number of quark content, i.e, baryons and mesons. Recent results from the ALICE Collaboration have shown that ϕ meson and proton v2 has a similar trend, possibly indicating that particle type grouping might be due to the mass of the particles and not the quark content. A stronger radial boost at LHC compared to RHIC seems to offer a consistent explanation to such observation. However, recalling that ϕ mesons decouple from the hadronic medium before additional radial flow is built up in the hadronic phase, a similar pattern in ϕ meson and proton v2 may not be due to radial flow alone. Our study reveals that models incorporating ϕ -meson production from K K ¯ fusion in the hadronic rescattering phase also predict a comparable magnitude of ϕ meson and proton v2 particularly in the intermediate region of pT. Whereas, v2 of ϕ mesons created in the partonic phase is in agreement with quark-coalescence motivated baryon-meson grouping of hadron v2. This observation seems to provide a plausible alternative interpretation for the apparent mass-like behavior of ϕ -meson v2. We have also observed a violation of hydrodynamical mass ordering between proton and ϕ meson v2 further supporting that ϕ mesons are negligibly affected by the collective radial flow in the hadronic phase due to the small in-medium hadronic interaction cross sections.
Spesyvyi, Anatolii; Smith, David; Španěl, Patrik
2015-12-15
A selected ion flow-drift tube mass spectrometric analytical technique, SIFDT-MS, is described that extends the established selected ion flow tube mass spectrometry, SIFT-MS, by the inclusion of a static but variable E-field along the axis of the flow tube reactor in which the analytical ion-molecule chemistry occurs. The ion axial speed is increased in proportion to the reduced field strength E/N (N is the carrier gas number density), and the residence/reaction time, t, which is measured by Hadamard transform multiplexing, is correspondingly reduced. To ensure a proper understanding of the physics and ion chemistry underlying SIFDT-MS, ion diffusive loss to the walls of the flow-drift tube and the mobility of injected H3O(+) ions have been studied as a function of E/N. It is seen that the derived diffusion coefficient and mobility of H3O(+) ions are consistent with those previously reported. The rate coefficient has been determined at elevated E/N for the association reaction of the H3O(+) reagent ions with H2O molecules, which is the first step in the production of H3O(+)(H2O)1,2,3 reagent hydrate ions. The production of hydrated analyte ion was also experimentally investigated. The analytical performance of SIFDT-MS is demonstrated by the quantification of acetone and isoprene in exhaled breath. Finally, the essential features of SIFDT-MS and SIFT-MS are compared, notably pointing out that a much lower speed of the flow-drive pump is required for SIFDT-MS, which facilitates the development of smaller cost-effective analytical instruments for real time breath and fluid headspace analyses.
Directory of Open Access Journals (Sweden)
S. Das
2015-01-01
Full Text Available The problem of unsteady free convection flow past an infinite vertical plate with heat and mass fluxes in the presence of thermal radiation is studied. The dimensionless coupled linear partial differential equations governing the flow are solved by employing the Laplace transform technique. Exact solutions have been obtained for the fluid velocity, temperature and mass concentration for the cases of both uniform heat flux (UHF and uniform wall temperature (UWT. The numerical results for the fluid velocity, temperature and mass concentration are presented graphically for various pertinent flow parameters and discussed in detail.
Construction of Penrose Diagrams for Dynamic Black Holes
Brown, Beth A.; Lindesay, James
2008-01-01
A set of Penrose diagrams is constructed in order to examine the large-scale causal structure of black holes with dynamic horizons. Coordinate dependencies of significant features, such as the event horizon and radial mass scale, are demonstrated on the diagrams. Unlike in static Schwarzschild geometries, the radial mass scale is clearly seen to differ from the horizon. Trajectories for photons near the horizon are briefly discussed.
Unravelling the multiphase run-out conditions of a slide-flow mass movement
van Asch, Th. W. J.; Xu, Q.; Dong, X. J.
2015-02-01
In this paper an attempt is made to unravel the run-out characteristics of a mass movement in the Sichuan Province, SW China by means of 1D numerical modelling and calibration on the topography of run-out profiles. The Dagou mass movement started as a rockslide with an initial volume of 480,000 m3, which transformed into a debris flow, increasing in volume due to entrainment of loose material in the upper part of the travelling track. The rapid mass movement had a run-out distance of 1380 m and a run-out time of about 50 s. Numerical calculations were conducted with the depth average shallow water equation to explain the variation in thickness of the debris flow deposits along the run-out track. For the calibration of the first run-out phase, three rheological models were applied, namely the Bingham, Voellmy and Quadratic rheology. Calibration was done on 1) the run-out distance, 2) the run-out time and 3) the goodness of fit with the thickness of the deposits along the track. In addition the erosion constant in the entrainment equation was calibrated on the observed versus calculated run-out volumes. Sensitivity analyses of the resistance parameters for the different rheologies showed that the viscosity, the basal friction, the turbulence term and the resistance factor are the most sensitive ones. It appeared that the variation in thickness along the run-out track can be explained by entrainment of material in the upper part of the track and a change in parametric values during the run-out process. The three rheologies produced a reasonable fit with the observed geometry of the run-out profile, run-out time and run-out volume. It was argued that the Voellmy rheology seems to give the most appropriate explanation for the difference in resistance along the run-out path. The main problem in the simulation was to stop the debris flow on a slope with a gradient around 22°. A reactivation of the mass movement by frictional sliding of the material half way the run
Thermal Cracking Analysis during Pipe Cooling of Mass Concrete Using Particle Flow Code
Directory of Open Access Journals (Sweden)
Liang Li
2016-01-01
Full Text Available Pipe cooling systems are among the potentially effective measures to control the temperature of mass concrete. However, if not properly controlled, thermal cracking in concrete, especially near water pipes, might occur, as experienced in many mass concrete structures. In this paper, a new numerical approach to simulate thermal cracking based on particle flow code is used to shed more light onto the process of thermal crack propagation and the effect of thermal cracks on thermal fields. Key details of the simulation, including the procedure of obtaining thermal and mechanical properties of particles, are presented. Importantly, a heat flow boundary based on an analytical solution is proposed and used in particle flow code in two dimensions to simulate the effect of pipe cooling. The simulation results are in good agreement with the monitored temperature data and observations on cored specimens from a real concrete gravity dam, giving confidence to the appropriateness of the adopted simulation. The simulated results also clearly demonstrate why thermal cracks occur and how they propagate, as well as the influence of such cracks on thermal fields.
Mass transfer from a circular cylinder: Effects of flow unsteadiness and slight nonuniformities
Marziale, M. L.; Mayle, R. E.
1984-01-01
Experiments were performed to determine the effect of periodic variations in the angle of the flow incident to a turbine blade on its leading edge heat load. To model this situation, measurements were made on a circular cylinder oscillating rotationally in a uniform steady flow. A naphthalene mass transfer technique was developed and used in the experiments and heat transfer rates are inferred from the results. The investigation consisted of two parts. In the first, a stationary cylinder was used and the transfer rate was measured for Re = 75,000 to 110,000 and turbulence levels from .34 percent to 4.9 percent. Comparisons with both theory and the results of others demonstrate that the accuracy and repeatability of the developed mass transfer technique is about + or - 2 percent, a large improvement over similar methods. In the second part identical flow conditions were used but the cylinder was oscillated. A Strouhal number range from .0071 to .1406 was covered. Comparisons of the unsteady and steady results indicate that the magnitude of the effect of oscillation is small and dependent on the incident turbulence conditions.
FINE MAGNETIC STRUCTURE AND ORIGIN OF COUNTER-STREAMING MASS FLOWS IN A QUIESCENT SOLAR PROMINENCE
Energy Technology Data Exchange (ETDEWEB)
Shen, Yuandeng; Liu, Yu; Xu, Zhi; Liu, Zhong [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650216 (China); Liu, Ying D. [State Key Laboratory of Space Weather, Chinese Academy of Sciences, Beijing 100190 (China); Chen, P. F. [School of Astronomy and Space Science, Nanjing University, Nanjing 210023 (China); Su, Jiangtao, E-mail: ydshen@ynao.ac.cn [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)
2015-11-20
We present high-resolution observations of a quiescent solar prominence that consists of a vertical and a horizontal foot encircled by an overlying spine and has ubiquitous counter-streaming mass flows. While the horizontal foot and the spine were connected to the solar surface, the vertical foot was suspended above the solar surface and was supported by a semicircular bubble structure. The bubble first collapsed, then reformed at a similar height, and finally started to oscillate for a long time. We find that the collapse and oscillation of the bubble boundary were tightly associated with a flare-like feature located at the bottom of the bubble. Based on the observational results, we propose that the prominence should be composed of an overlying horizontal spine encircling a low-lying horizontal and vertical foot, in which the horizontal foot consists of shorter field lines running partially along the spine and has ends connected to the solar surface, while the vertical foot consists of piling-up dips due to the sagging of the spine fields and is supported by a bipolar magnetic system formed by parasitic polarities (i.e., the bubble). The upflows in the vertical foot were possibly caused by the magnetic reconnection at the separator between the bubble and the overlying dips, which intruded into the persistent downflow field and formed the picture of counter-streaming mass flows. In addition, the counter-streaming flows in the horizontal foot were possibly caused by the imbalanced pressure at the both ends.
Non-basal dislocations should be accounted for in simulating ice mass flow
Chauve, T.; Montagnat, M.; Piazolo, S.; Journaux, B.; Wheeler, J.; Barou, F.; Mainprice, D.; Tommasi, A.
2017-09-01
Prediction of ice mass flow and associated dynamics is pivotal at a time of climate change. Ice flow is dominantly accommodated by the motion of crystal defects - the dislocations. In the specific case of ice, their observation is not always accessible by means of the classical tools such as X-ray diffraction or transmission electron microscopy (TEM). Part of the dislocation population, the geometrically necessary dislocations (GNDs) can nevertheless be constrained using crystal orientation measurements via electron backscattering diffraction (EBSD) associated with appropriate analyses based on the Nye (1950) approach. The present study uses the Weighted Burgers Vectors, a reduced formulation of the Nye theory that enables the characterization of GNDs. Applied to ice, this method documents, for the first time, the presence of dislocations with non-basal [ c ] or Burgers vectors. These [ c ] or dislocations represent up to 35% of the GNDs observed in laboratory-deformed ice samples. Our findings offer a more complex and comprehensive picture of the key plasticity processes responsible for polycrystalline ice creep and provide better constraints on the constitutive mechanical laws implemented in ice sheet flow models used to predict the response of Earth ice masses to climate change.
Knot probabilities in random diagrams
Cantarella, Jason; Chapman, Harrison; Mastin, Matt
2016-10-01
We consider a natural model of random knotting—choose a knot diagram at random from the finite set of diagrams with n crossings. We tabulate diagrams with 10 and fewer crossings and classify the diagrams by knot type, allowing us to compute exact probabilities for knots in this model. As expected, most diagrams with 10 and fewer crossings are unknots (about 78% of the roughly 1.6 billion 10 crossing diagrams). For these crossing numbers, the unknot fraction is mostly explained by the prevalence of ‘tree-like’ diagrams which are unknots for any assignment of over/under information at crossings. The data shows a roughly linear relationship between the log of knot type probability and the log of the frequency rank of the knot type, analogous to Zipf’s law for word frequency. The complete tabulation and all knot frequencies are included as supplementary data.
Institute of Scientific and Technical Information of China (English)
Yi Wu; Hangfeng Wang; Zhaohui Liu; Jing Li; Liqi Zhang; Chuguang Zheng
2006-01-01
Particle-laden flows in a horizontal channel were investigated by means of a two-phase particle image velocimetry (PIV) technique.Experiments were performed at a Reynolds number of 6826 and the flow is seeded with polythene beads of two sizes,60μm and 110μm.One was slightly smaller than and the other was larger than the Kolmogorov length scale.The particle loadings were relatively low,with mass loading ratio ranging from 5×10-4 to 4×10-2 and volume fractions from 6×10-7 to 4.8×10-5,respectively.The results show that the presence of particles can dramatically modify the turbulence even under the lowest mass loading ratio of 5×10-4.The mean flow is attenuated and decreased with increasing particle size and mass loading The turbulence intensities are enhanced in all the cases concerned.With the increase of the mass loading,the intensities vary in a complicated manner in the case of small particles,indicating complicated particle-turbulence interactions;whereas they increase monotonously in the case of large particles.The particle velocities and concentrations are also given.The particles lag behind the fluid in the center region but lead in the wall region,and this trend is more prominent for the large particles.The streamwise particle fluctuations are larger than the gas fluctuations for both sizes of particles,however their varying trend with the mass loadings is not so clear.The wallnormal fluctuations increase with increasing mass loadings.They are smaller in the 60μm particle case but larger in the 110μm particle case than those of the gas phase.It seems that the small particles follow the fluid motion to certain extent while the larger particles are more likely dominated by their own inertia.Finally,remarkable non-uniform distributions of particle concentration are observed,especially for the large particles.The inertia of particles is proved to be very important for the turbulence modification and particles behaviors and thus should be considered in
Collective neurodynamics: Phase diagram
Ovchinnikov, Igor V.; Li, Wenyuan; Schwartz, Robert N.; Hudson, Andrew E.; Meier, Karlheinz; Wang, Kang L.
2016-01-01
Here, we conceptualize the phase diagram of collective short-term bio-chemo-electric component of neurodynamics (S-ND) on the parameter space of externally, e.g., pharmacologically, controllable single-neuron parameters such as the resting potential and/or firing threshold, repolarization time, etc. This concept may become a useful tool for the systematization of knowledge in anesthesiology and provide a fruitful venue for future studies of the high-level S-ND functionalities such as short-te...
Diagramming Complex Activities
DEFF Research Database (Denmark)
Andersen, Peter Bøgh
2005-01-01
We increasingly live in heterogeneous ever-changing webs of activities where human actions are intertwined with events created by automatic machines. In order to make such webs understandable to its human participants, their structure should be represented by displays emphasizing their action as...... aspect. The paper suggests thematic roles as a semantics for actions, argues that a selection of well-known diagramming techniques can be defined within this theory, and uses the theory to discuss new issues related to process control and mobile technology....
Smolec, Radoslaw; Dziembowski, Wojciech; Moskalik, Pawel; Netzel, Henryka; Prudil, Zdenek; Skarka, Marek; Soszynski, Igor
2017-09-01
Over the recent years, the Petersen diagram for classical pulsators, Cepheids and RR Lyr stars, populated with a few hundreds of new multiperiodic variables. We review our analyses of the OGLE data, which resulted in a significant extension of the known, and in the discovery of a few new and distinct forms of multiperiodic pulsation. The showcase includes not only radial mode pulsators, but also radial-non-radial pulsators and stars with significant modulation observed on top of the beat pulsation. First theoretical models explaining the new forms of stellar variability are briefly discussed.
Lagrangian mass-flow investigations of inorganic contaminants in wastewater-impacted streams
Barber, L.B.; Antweiler, R.C.; Flynn, J.L.; Keefe, S.H.; Kolpin, D.W.; Roth, D.A.; Schnoebelen, D.J.; Taylor, H.E.; Verplanck, P.L.
2011-01-01
Understanding the potential effects of increased reliance on wastewater treatment plant (WWTP) effluents to meet municipal, agricultural, and environmental flow requires an understanding of the complex chemical loading characteristics of the WWTPs and the assimilative capacity of receiving waters. Stream ecosystem effects are linked to proportions of WWTP effluent under low-flow conditions as well as the nature of the effluent chemical mixtures. This study quantifies the loading of 58 inorganic constituents (nutrients to rare earth elements) from WWTP discharges relative to upstream landscape-based sources. Stream assimilation capacity was evaluated by Lagrangian sampling, using flow velocities determined from tracer experiments to track the same parcel of water as it moved downstream. Boulder Creek, Colorado and Fourmile Creek, Iowa, representing two different geologic and hydrologic landscapes, were sampled under low-flow conditions in the summer and spring. One-half of the constituents had greater loads from the WWTP effluents than the upstream drainages, and once introduced into the streams, dilution was the predominant assimilation mechanism. Only ammonium and bismuth had significant decreases in mass load downstream from the WWTPs during all samplings. The link between hydrology and water chemistry inherent in Lagrangian sampling allows quantitative assessment of chemical fate across different landscapes. ?? 2011 American Chemical Society.
Simulation of incompressible flows with heat and mass transfer using parallel finite element method
Directory of Open Access Journals (Sweden)
Jalal Abedi
2003-02-01
Full Text Available The stabilized finite element formulations based on the SUPG (Stream-line-Upwind/Petrov-Galerkin and PSPG (Pressure-Stabilization/Petrov-Galerkin methods are developed and applied to solve buoyancy-driven incompressible flows with heat and mass transfer. The SUPG stabilization term allows us to solve flow problems at high speeds (advection dominant flows and the PSPG term eliminates instabilities associated with the use of equal order interpolation functions for both pressure and velocity. The finite element formulations are implemented in parallel using MPI. In parallel computations, the finite element mesh is partitioned into contiguous subdomains using METIS, which are then assigned to individual processors. To ensure a balanced load, the number of elements assigned to each processor is approximately equal. To solve nonlinear systems in large-scale applications, we developed a matrix-free GMRES iterative solver. Here we totally eliminate a need to form any matrices, even at the element levels. To measure the accuracy of the method, we solve 2D and 3D example of natural convection flows at moderate to high Rayleigh numbers.
Experimental investigation on mass flow rate measurements using fibre Bragg grating sensors
Thekkethil, S. R.; Thomas, R. J.; Neumann, H.; Ramalingam, R.
2017-02-01
Flow measurement and control of cryogens is one of the major requirements of systems such as superconductor magnets for fusion reactors, MRI magnets etc. They can act as an early diagnostic tool for detection of any faults and ensure correct distribution of cooling load while also accessing thermal performance of the devices. Fibre Bragg Grating (FBG) sensors provide compact and accurate measurement systems which have added advantages such as immunity towards electrical and magnetic interference, low attenuation losses and remote sensing. This paper summarizes the initial experimental investigations and calibration of a novel FBG based mass flow meter. This design utilizes the viscous drag due to the flow to induce a bending strain on the fibre. The strain experienced by the fibre will be proportional to the flowrate and can be measured in terms of Bragg wavelength shift. The flowmeter is initially tested at atmospheric conditions using helium. The results are summarized and the performance parameters of the sensor are estimated. The results were also compared to a numerical model and further results for liquid helium is also reported. An overall sensitivity of 29 pm.(g.s-1)-1 was obtained for a helium flow, with a resolution of 0.2 g.s-1. A hysteresis error of 8 pm was also observed during load-unload cycles. The sensor is suitable for further tests using cryogens.
Numerical study of streamwise and cross flow in the presence of heat and mass transfer
Rizwan-ul-Haq; Soomro, Feroz Ahmed; Khan, Z. H.; Al-Mdallal, Qasem M.
2017-05-01
The present model is devoted to investigate the streamwise and cross flow of a viscous fluid over a heated moving surface. Viscous dissipation effects are also considered with heat and mass transfer effects and these effects with cross flow have not been explored yet in the literature. Governing boundary layer equations consist in the form of nonlinear partial differential equations (PDEs). Compatible transformations are applied to change such equations into ordinary differential equations which are further solved using the Runge-Kutta technique and shooting method. Linear stability analysis is also performed over the obtained solutions to validate the results and to determine the smallest eigenvalues. Three different kinds of fluids namely: acetone, water and ethaline glycol are investigated to analyse the heat transfer rate. The problem contains important physical parameters namely: Prandtl number, Eckert numbers and Lewis number. The obtained solutions are discussed in detail against each physical parameter using graphs and tables.
Mass transport aspects of polymer electrolyte fuel cells under two-phase flow conditions
Energy Technology Data Exchange (ETDEWEB)
Kramer, D.
2007-03-15
This well-illustrated, comprehensive dissertation by Dr. Ing. Denis Kramer takes an in-depth look at polymer electrolyte fuel cells (PEFC) and the possibilities for their application. First of all, the operating principles of polymer electrolyte fuel cells are described and discussed, whereby thermodynamics aspects and loss mechanisms are examined. The mass transport diagnostics made with respect to the function of the cells are discussed. Field flow geometry, gas diffusion layers and, amongst other things, liquid distribution, the influence of flow direction and the low-frequency behaviour of air-fed PEFCs are discussed. Direct methanol fuel cells are examined, as are the materials chosen. The documentation includes comprehensive mathematical and graphical representations of the mechanisms involved.
Energy Technology Data Exchange (ETDEWEB)
Oliveira, Jorge Luiz Goes; Passos, Julio Cesar [Departamento de Engenharia Mecanica-LEPTEN/Boiling-UFSC, Campus Universitario, Trindade, 88.040-900 Florianopolis-SC (Brazil); Verschaeren, Ruud; Geld, Cees van der [Eindhoven University of Technology, Faculty of Mechanical Engineering, W-hoog 2.135, P.O. Box 513, 5600 MB, Eindhoven (Netherlands)
2009-01-15
Two-phase flow measurements were carried out using a resistive void fraction meter coupled to a venturi or orifice plate. The measurement system used to estimate the liquid and gas mass flow rates was evaluated using an air-water experimental facility. Experiments included upward vertical and horizontal flow, annular, bubbly, churn and slug patterns, void fraction ranging from 2% to 85%, water flow rate up to 4000 kg/h, air flow rate up to 50 kg/h, and quality up to almost 10%. The fractional root mean square (RMS) deviation of the two-phase mass flow rate in upward vertical flow through a venturi plate is 6.8% using the correlation of Chisholm (D. Chisholm, Pressure gradients during the flow of incompressible two-phase mixtures through pipes, venturis and orifice plates, British Chemical Engineering 12 (9) (1967) 454-457). For the orifice plate, the RMS deviation of the vertical flow is 5.5% using the correlation of Zhang et al. (H.J. Zhang, W.T. Yue, Z.Y. Huang, Investigation of oil-air two-phase mass flow rate measurement using venturi and void fraction sensor, Journal of Zhejiang University Science 6A (6) (2005) 601-606). The results show that the flow direction has no significant influence on the meters in relation to the pressure drop in the experimental operation range. Quality and slip ratio analyses were also performed. The results show a mean slip ratio lower than 1.1, when bubbly and slug flow patterns are encountered for mean void fractions lower than 70%. (author)
Heat and mass transfer from the mantle: heat flow and He-isotope constraints
Directory of Open Access Journals (Sweden)
B. G. Polyak
2005-06-01
Full Text Available Terrestrial heat flow density, q, is inversely correlated with the age, t, of tectono-magmatic activity in the Earth's crust (Polyak and Smirnov, 1966; etc.. «Heat flow-age dependence» indicates unknown temporal heat sources in the interior considered a priori as the mantle-derived diapirs. The validity of this hypothesis is demonstrated by studying the helium isotope ratio, 3He/4He = R, in subsurface fluids. This study discovered the positive correlation between the regionally averaged (background estimations of R- and q-values (Polyak et al., 1979a. Such a correlation manifests itself in both pan-regional scales (Norhtern Eurasia and separate regions, e.g., Japan (Sano et al., 1982, Eger Graben (Polyak et al., 1985 Eastern China rifts (Du, 1992, Southern Italy (Italiano et al., 2000, and elsewhere. The R-q relation indicates a coupled heat and mass transfer from the mantle into the crust. From considerations of heat-mass budget this transfer can be provided by the flux consisting of silicate matter rather than He or other volatiles. This conclusion is confirmed by the correlation between 3He/ 4He and 87Sr/86Sr ratios in the products of the volcanic and hydrothermal activity in Italy (Polyak et al., 1979b; Parello et al., 2000 and other places. Migration of any substance through geotemperature field transports thermal energy accumulated within this substance, i.e. represents heat and mass transfer. Therefore, only the coupled analysis of both material and energy aspects of this transfer makes it possible to characterise the process adequately and to decipher an origin of terrestrial heat flow observed in upper parts of the earth crust. An attempt of such kind is made in this paper.
Reactions of Ions with Ionic Liquid Vapors by Selected-Ion Flow Tube Mass Spectrometry
2016-06-07
spectrometric methods14 and, more recently, IR5,6 and UVvis spectroscopy.7 Indirect methods involve transpiration,8 effusion,9 or thermal gravimetric analyses... experimental mass peaks observed for EMIMþNTf2 are listed in Table 1, along with their enthalpies and free energies of reaction (at 298 K). In the cases...ion trio definitely shows the presence of neutral RTIL vapors in the flow tube. The calculated geometry of EMIMþNTf2 NH4 þ in Figure 3 shows a dramatic
Directory of Open Access Journals (Sweden)
Faiz G Awad
Full Text Available In this study, the Spectral Relaxation Method (SRM is used to solve the coupled highly nonlinear system of partial differential equations due to an unsteady flow over a stretching surface in an incompressible rotating viscous fluid in presence of binary chemical reaction and Arrhenius activation energy. The velocity, temperature and concentration distributions as well as the skin-friction, heat and mass transfer coefficients have been obtained and discussed for various physical parametric values. The numerical results obtained by (SRM are then presented graphically and discussed to highlight the physical implications of the simulations.
Analysis of heat and mass transfers in two-phase flow by coupling optical diagnostic techniques
Energy Technology Data Exchange (ETDEWEB)
Lemaitre, P.; Porcheron, E. [Institut de Radioprotection et de Surete Nucleaire, Saclay (France)
2008-08-15
During the course of a hypothetical accident in a nuclear power plant, spraying might be actuated to reduce static pressure in the containment. To acquire a better understanding of the heat and mass transfers between a spray and the surrounding confined gas, non-intrusive optical measurements have to be carried out simultaneously on both phases. The coupling of global rainbow refractometry with out-of-focus imaging and spontaneous Raman scattering spectroscopy allows us to calculate the local Spalding parameter B{sub M}, which is useful in describing heat transfer associated with two-phase flow. (orig.)
Three-dimensional flow of Powell-Eyring nanofluid with heat and mass flux boundary conditions
Tasawar, Hayat; Ikram, Ullah; Taseer, Muhammad; Ahmed, Alsaedi; Sabir, Ali Shehzad
2016-07-01
This article investigates the three-dimensional flow of Powell-Eyring nanofluid with thermophoresis and Brownian motion effects. The energy equation is considered in the presence of thermal radiation. The heat and mass flux conditions are taken into account. Mathematical formulation is carried out through the boundary layer approach. The governing partial differential equations are transformed into the nonlinear ordinary differential equations through suitable variables. The resulting nonlinear ordinary differential equations have been solved for the series solutions. Effects of emerging physical parameters on the temperature and nanoparticles concentration are plotted and discussed. Numerical values of local Nusselt and Sherwood numbers are computed and examined.
Directory of Open Access Journals (Sweden)
Chandrakala P.
2014-02-01
Full Text Available The effects of thermal radiation on a flow past an impulsively started infinite vertical plate in the presence of a magnetic field have been studied. The fluid considered is a gray, absorbing-emitting radiation but non-scattering medium. The dimensionless governing equations are solved by an efficient, more accurate, unconditionally stable and fast converging implicit scheme. The effects of velocity and temperature for different parameters such as the thermal radiation, magnetic field, Schmidt number, thermal Grashof number and mass Grashof number are studied. It is observed that the velocity decreases in the presence of thermal radiation or a magnetic field
Modeling tangent hyperbolic nanoliquid flow with heat and mass flux conditions
Hayat, T.; Ullah, I.; Alsaedi, A.; Ahmad, B.
2017-03-01
This attempt predicts the hydromagnetic flow of a tangent hyperbolic nanofluid originated by a non-linear impermeable stretching surface. The considered nanofluid model takes into account the Brownian diffusion and thermophoresis characteristics. An incompressible liquid is electrically conducted in the presence of a non-uniformly applied magnetic field. Heat and mass transfer phenomena posses flux conditions. Mathematical formulation is developed by utilizing the boundary layer approach. A system of ordinary differential equations is obtained by employing adequate variables. Convergence for obtained series solutions is checked and explicitly verified through tables and plots. Effects of numerous pertinent variables on velocity, temperature and concentration fields are addressed. Computations for surface drag coefficient, heat transfer rate and mass transfer rate are presented and inspected for the influence of involved variables. Temperature is found to enhance for a higher magnetic variable. Present and previous outcomes in limiting sense are also compared.
Hydrodynamics and Mass Transfer of Jet Co-flow Packing Tray
Institute of Scientific and Technical Information of China (English)
刘国标; 兰仁水; 王树楹; 余国琮
2005-01-01
The jet co-flow packing tray(JCPT) with three different types of perforation in equal opening fraction was tested in two rectangular columns with 0.12 m in width and 0.27 m in length operated with air-water system.The influences of gas phase orifice F-factor and clear liquid height He on the amount of liquid lifted, Q, were examined. The corresponding correlation between Q with F-factor and equivalent diameter of perforated holes as well as Hc was obtained. Furthermore, the non-steady state mass transfer performance of JCPT was tested by the humidification of air with water. Finally, by the analysis of data and comparison, it was found that the JCPT tray with single cap and two holes exhibited the highest mass transfer efficiency and best performance.
Grote, Jan-Philipp; Zeradjanin, Aleksandar R.; Cherevko, Serhiy; Mayrhofer, Karl J. J.
2014-10-01
In this work the online coupling of a miniaturized electrochemical scanning flow cell (SFC) to a mass spectrometer is introduced. The system is designed for the determination of reaction products in dependence of the applied potential and/or current regime as well as fast and automated change of the sample. The reaction products evaporate through a hydrophobic PTFE membrane into a small vacuum probe, which is positioned only 50-100 μm away from the electrode surface. The probe is implemented into the SFC and directly connected to the mass spectrometer. This unique configuration enables fast parameter screening for complex electrochemical reactions, including investigation of operation conditions, composition of electrolyte, and material composition. The technical developments of the system are validated by initial measurements of hydrogen evolution during water electrolysis and electrochemical reduction of CO2 to various products, showcasing the high potential for systematic combinatorial screening by this approach.
Wang, Z. Y.; Wang, G. Y.; Hu, C. L.; Cui, Z. Y.
2015-01-01
The objective of this paper is mainly to study the influence of cavitation on the added mass and damping force coefficient. Based on Reynolds averaged Navier-Stokes equations, the dynamic mesh is used to calculate the added mass, and the rotating coordinate frame method is applied to research on the damping force coefficient. In order to obtain fluid damping force coefficients, the movement pattern is set as a uniform circular motion. Then the additional force coefficient and pitch damping moment coefficient could be obtained using the method of least squares. The result shows that the method to calculate added mass is reliable by comparing with the analytical solution. With the cavitation number decreasing, the absolute value of the added mass of λ22 decreases and λ26 increases. What's more, both the absolute value of damping force and moment coefficient decrease substantially with the development of cavity when the cavitation number is larger than 0.45. However, with the cavitation number less than 0.45, the un-symmetric cavity is more prominent, the absolute value of damping force and moment coefficient increase slightly. This is probably caused by the strengthened pressure peak at the suction side induced by the re-entrant flow.
Villafane, Laura; Banko, Andrew; Elkins, Chris; Eaton, John
2016-11-01
The momentum coupled dynamics of particles and turbulence are experimentally investigated in a vertical fully developed turbulent square duct flow of air laden with Nickel particles. Significant preferential concentration is present for the Stokes numbers investigated, which vary from 3 to 30 based on the Kolmogorov time scale. Higher order measures of preferential concentration, such as the sizes and shapes of clusters and voids, are analyzed for increasing mass loading ratios. The mass loadings chosen span the one-way and two-way coupled regimes, while the volume loading is kept low. The effect of Stokes number and mass loading is also evaluated for particle velocity statistics and compared to the unladen gas statistics. Planar laser scattering is used to record instantaneous particle images in the center of the duct. Preferential concentration statistics are computed from box counting and Voronoi tessellation algorithms. PIV and PTV techniques are used to calculate particle velocity statistics. The analysis is extended to the near wall region in the logarithmic layer for the case of low mass loading. These results are compared to those from the duct center to assess the effects of strong carrier phase inhomogeneity on the particle distributions. This Material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0002373-1.
Pivovarova, E. A.; Smirnovsky, A. A.; Schmidt, A. A.
2013-11-01
Mathematical modeling of flow in the differential chamber of the gas-dynamic interface of a portable mass-spectrometer was carried out to comprehensively study the flow structure and make recommendations for the optimization of the gas-dynamic interface. Modeling was performed using an OpenFOAM open computational platform. Conditions for an optimal operating mode of the differential chamber were determined.
Ridder, van de L.; Hakvoort, W.B.J.; Dijk, van J.; Lötters, J.C.; Boer, de A.; Dimitrovova, Z.; Almeida, de J.R.
2013-01-01
In this paper the quantitative influence of external vibrations on the measurement value of a Coriolis Mass-Flow Meter for low flows is investigated, with the eventual goal to reduce the influence of vibrations. Model results are compared with experimental results to improve the knowledge on how ext
Kauppila, TJ; Bruins, AP; Kostiainen, R
In the novel atmospheric pressure photoionization-mass spectrometry the ionization efficiency has been observed to decrease when the solvent flow rate is increased. The effect of the flow rate on the ionization efficiency was studied by comparing the behavior of two analytes, one of which is ionized
Krot, A. M.
2009-04-01
A statistical theory for a cosmological body forming based on the spheroidal body model has been proposed in the works [1]-[4]. This work studies a slowly evolving process of gravitational condensation of a spheroidal body from an infinitely distributed gas-dust substance in space. The equation for an initial evolution of mass density function of a gas-dust cloud is considered here. It is found this equation coincides completely with the analogous equation for a slowly gravitational compressed spheroidal body [5]. A conductive flow in dissipative systems was investigated by I. Prigogine in his works (see, for example, [6], [7]). As it has been found in [2], [5], there exists a conductive antidiffusion flow in a slowly compressible gravitating spheroidal body. Applying the equation of continuity to this conductive flow density we obtain a linear antidiffusion equation [5]. However, if an intensity of conductive flow density increases sharply then the linear antidiffusion equation becomes a nonlinear one. Really, it was pointed to [6] analogous linear equations of diffusion or thermal conductivity transform in nonlinear equations respectively. In this case, the equation of continuity describes a nonlinear mass flow being a source of instabilities into a gravitating spheroidal body because the gravitational compression factor G is a function of not only time but a mass density. Using integral substitution we can reduce a nonlinear antidiffusion equation to the linear antidiffusion equation relative to a new function. If the factor G can be considered as a specific angular momentum then the new function is an angular momentum density. Thus, a nonlinear momentum density flow induces a flow of angular momentum density because streamlines of moving continuous substance come close into a gravitating spheroidal body. Really, the streamline approach leads to more tight interactions of "liquid particles" that implies a superposition of their specific angular momentums. This
Directory of Open Access Journals (Sweden)
Amy L Moran
Full Text Available BACKGROUND: Many aquatic animals enclose embryos in gelatinous masses, and these embryos rely on diffusion to supply oxygen. Mass structure plays an important role in limiting or facilitating O2 supply, but external factors such as temperature and photosynthesis can play important roles as well. Other external factors are less well understood. METHODOLOGY/PRINCIPAL FINDINGS: We first explored the effects of water flow on O2 levels inside nudibranch embryo masses and compared the effects of flow on masses from temperate and polar regions. Water flow (still vs. vigorously bubbled had a strong effect on central O2 levels in all masses; in still water, masses were considerably more hypoxic than in bubbled water. This effect was stronger in temperate than in polar masses, likely due to the increased metabolic demand and O2 consumption of temperate masses. Second, we made what are to our knowledge the first measurements of O2 in invertebrate masses in the field. Consistent with laboratory experiments, O2 in Antarctic masses was high in masses in situ, suggesting that boundary-layer effects do not substantially limit O2 supply to polar embryos in the field. CONCLUSIONS/SIGNIFICANCE: All else being equal, boundary layers are more likely to depress O2 in masses in temperate or tropical regions; thus, selection on parents to choose high-flow sites for mass deposition is likely greater in warm water. Because of the large number of variables affecting diffusive O2 supply to embryos in their natural environment, field observations are necessary to test hypotheses generated from laboratory experiments and mathematical modeling.
Moran, Amy L; Woods, H Arthur
2010-08-11
Many aquatic animals enclose embryos in gelatinous masses, and these embryos rely on diffusion to supply oxygen. Mass structure plays an important role in limiting or facilitating O2 supply, but external factors such as temperature and photosynthesis can play important roles as well. Other external factors are less well understood. We first explored the effects of water flow on O2 levels inside nudibranch embryo masses and compared the effects of flow on masses from temperate and polar regions. Water flow (still vs. vigorously bubbled) had a strong effect on central O2 levels in all masses; in still water, masses were considerably more hypoxic than in bubbled water. This effect was stronger in temperate than in polar masses, likely due to the increased metabolic demand and O2 consumption of temperate masses. Second, we made what are to our knowledge the first measurements of O2 in invertebrate masses in the field. Consistent with laboratory experiments, O2 in Antarctic masses was high in masses in situ, suggesting that boundary-layer effects do not substantially limit O2 supply to polar embryos in the field. All else being equal, boundary layers are more likely to depress O2 in masses in temperate or tropical regions; thus, selection on parents to choose high-flow sites for mass deposition is likely greater in warm water. Because of the large number of variables affecting diffusive O2 supply to embryos in their natural environment, field observations are necessary to test hypotheses generated from laboratory experiments and mathematical modeling.
ULTRAVIOLET SPECTROSCOPIC ANALYSIS OF TRANSIENT MASS FLOW OUTBURST IN U CEPHEI
Energy Technology Data Exchange (ETDEWEB)
Tupa, Peter R.; DeLeo, Gary G.; McCluskey, George E. [Physics Department, Lehigh University, Bethlehem, PA 18015 (United States); Kondo, Yoji [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Sahade, Jorge [Facultad de Ciencias Astronómicas, Paseo del Bosque s/n, B1900FWA-La Plata (Argentina); Giménez, Alvaro [Centro de Astrobiologia, CSIC/INTA, Carretera de Torrejon a Ajalvir, E-28850 Torrejon de Ardoz (Madrid) (Spain); Caton, Daniel B., E-mail: pet205@lehigh.edu [Appalachian State University, Boone, NC 28608 (United States)
2013-09-20
Spectra from the International Ultraviolet Explorer taken in 1989 September over one full orbital period of U Cephei (U Cep, HD 5796) are analyzed. The TLUSTY and SYNSPEC stellar atmospheric simulation programs are used to generate synthetic spectra to which U Cep continuum levels are normalized. Absorption lines attributed to the photosphere are divided out to isolate mass flow and accretion spectra. A radial velocity curve is constructed for conspicuous gas stream features, and shows evidence for a transient flow during secondary eclipse with outward velocities ranging between 200 and 350 km s{sup –1}, and a number density of (3 ± 2) × 10{sup 10} cm{sup –3}. The validity of C IV 1548 and 1550 and Si IV 1393 and 1402 lines are re-examined in the context of extreme rotational blending effects. A G-star to B-star mass transfer rate of (5 ± 4) × 10{sup –9} M{sub ☉} yr{sup –1} is calculated as an approximate upper limit, and a model system is presented.
Mass flow facilitates tungsten blistering under 60 keV helium ion implantation
Han, Wenjia; Yu, Jiangang; Chen, Zhe; Lu, Guanghong; Zhu, Kaigui
2017-07-01
Gaseous ion implantation induces displacement damage and gaseous atom uptake in the target material and is widely adopted to simulate plasma-material interaction in fusion devices. Here we report an observation of tungsten blistering with large plastic deformation under 60 keV helium ion implantation at room temperature. The near-surface morphology and microstructure analyses suggest more than 50% plastic elongation and breakdown of lattice periodicity in the blister caps. We propose that collision cascades and high-concentration helium atoms not only greatly modify the tungsten microstructure, but also enhance mass flow in terms of point defect diffusion in blister caps. The mass flow ultimately aggravates the relaxation of stresses in the tungsten surface and facilitates tungsten blistering during high-energy gaseous ion implantation. We sketch out the blistering process and stress the vital importance of dynamic processes in the response of plasma-facing materials subjected to low-energy plasma penetration and high-energy neutron bombardment in fusion devices.
Poda, A R; Bednar, A J; Kennedy, A J; Harmon, A; Hull, M; Mitrano, D M; Ranville, J F; Steevens, J
2011-07-01
The ability to detect and identify the physiochemical form of contaminants in the environment is important for degradation, fate and transport, and toxicity studies. This is particularly true of nanomaterials that exist as discrete particles rather than dissolved or sorbed contaminant molecules in the environment. Nanoparticles will tend to agglomerate or dissolve, based on solution chemistry, which will drastically affect their environmental properties. The current study investigates the use of field flow fractionation (FFF) interfaced to inductively coupled plasma-mass spectrometry (ICP-MS) as a sensitive and selective method for detection and characterization of silver nanoparticles. Transmission electron microscopy (TEM) is used to verify the morphology and primary particle size and size distribution of precisely engineered silver nanoparticles. Subsequently, the hydrodynamic size measurements by FFF are compared to dynamic light scattering (DLS) to verify the accuracy of the size determination. Additionally, the sensitivity of the ICP-MS detector is demonstrated by fractionation of μg/L concentrations of mixed silver nanoparticle standards. The technique has been applied to nanoparticle suspensions prior to use in toxicity studies, and post-exposure biological tissue analysis. Silver nanoparticles extracted from tissues of the sediment-dwelling, freshwater oligochaete Lumbriculus variegatus increased in size from approximately 31-46nm, indicating a significant change in the nanoparticle characteristics during exposure.
Program Synthesizes UML Sequence Diagrams
Barry, Matthew R.; Osborne, Richard N.
2006-01-01
A computer program called "Rational Sequence" generates Universal Modeling Language (UML) sequence diagrams of a target Java program running on a Java virtual machine (JVM). Rational Sequence thereby performs a reverse engineering function that aids in the design documentation of the target Java program. Whereas previously, the construction of sequence diagrams was a tedious manual process, Rational Sequence generates UML sequence diagrams automatically from the running Java code.
Flow Diagram Decomposition Using Graph Transformations
Rensink, Arend; Zimakova, M.V.
2009-01-01
The key challenge of model transformations in model-driven development is in transforming higher-level abstract models into more concrete ones that can be used to generate implementation level models, including executable business process representations and program code. Many of the modelling
Iverson, R.M.; Denlinger, R.P.
2001-01-01
Rock avalanches, debris flows, and related phenomena consist of grain-fluid mixtures that move across three-dimensional terrain. In all these phenomena the same basic forces, govern motion, but differing mixture compositions, initial conditions, and boundary conditions yield varied dynamics and deposits. To predict motion of diverse grain-fluid masses from initiation to deposition, we develop a depth-averaged, threedimensional mathematical model that accounts explicitly for solid- and fluid-phase forces and interactions. Model input consists of initial conditions, path topography, basal and internal friction angles of solid grains, viscosity of pore fluid, mixture density, and a mixture diffusivity that controls pore pressure dissipation. Because these properties are constrained by independent measurements, the model requires little or no calibration and yields readily testable predictions. In the limit of vanishing Coulomb friction due to persistent high fluid pressure the model equations describe motion of viscous floods, and in the limit of vanishing fluid stress they describe one-phase granular avalanches. Analysis of intermediate phenomena such as debris flows and pyroclastic flows requires use of the full mixture equations, which can simulate interaction of high-friction surge fronts with more-fluid debris that follows. Special numerical methods (described in the companion paper) are necessary to solve the full equations, but exact analytical solutions of simplified equations provide critical insight. An analytical solution for translational motion of a Coulomb mixture accelerating from rest and descending a uniform slope demonstrates that steady flow can occur only asymptotically. A solution for the asymptotic limit of steady flow in a rectangular channel explains why shear may be concentrated in narrow marginal bands that border a plug of translating debris. Solutions for static equilibrium of source areas describe conditions of incipient slope instability
The equilibrium flow and mass balance of the Taku Glacier, Alaska 1950–2006
Directory of Open Access Journals (Sweden)
K. F. Sprenke
2008-05-01
Full Text Available The Taku Glacier, Alaska has advanced 7.5 km since the late nineteenth century, while all other primary outlet glaciers of the Juneau Icefield are in retreat. The Juneau Icefield Research Program has completed field work on the Taku Glacier annually since 1946. The collected observations of surface mass balance, glacier velocity and glacier thickness at Profile IV 29 km above the terminus and 4 km above the equilibrium line provide a means to assess the equilibrium nature of the Taku Glacier. Velocity measured over a twelve month span and annual summer velocity measurements completed at a Profile IV from 1950–2006 indicate insignificant variations in velocity seasonally or from year to year. The consistency of velocity over the 56-year period indicates that in the vicinity of the equilibrium line, the flow of the Taku Glacier has been in an equilibrium state. Surface mass balance was positive from 1946–1988 averaging +0.42 m a−1. This led to glacier thickening. From 1988–2006 an important change has occurred and annual balance has been −0.14 m a−1, and the glacier thickness has ceased increasing along Profile IV. Field measurements of ice depth and surface velocity allow calculation of the volume flux at Profile IV. Volume flux is then compared with the surface balance flux from the region of the glacier above Profile IV, determined annually in the field. Above Profile IV the observed mean surface flux is 5.50×108 m3/a (±5%, while the calculated volume flux range flowing through profile IV is 5.00–5.47×108 m3/a. The mean surface flux has been greater than the volume flux, which has led to slow thickening of the Taku Glacier up to 1988. The thickening has not led to a change in the flow of Taku Glacier at Profile IV.
Enhanced stability of steep channel beds to mass failure and debris flow initiation
Prancevic, J.; Lamb, M. P.; Ayoub, F.; Venditti, J. G.
2015-12-01
Debris flows dominate bedrock erosion and sediment transport in very steep mountain channels, and are often initiated from failure of channel-bed alluvium during storms. While several theoretical models exist to predict mass failures, few have been tested because observations of in-channel bed failures are extremely limited. To fill this gap in our understanding, we performed laboratory flume experiments to identify the conditions necessary to initiate bed failures in non-cohesive sediment of different sizes (D = 0.7 mm to 15 mm) on steep channel-bed slopes (S = 0.45 to 0.93) and in the presence of water flow. In beds composed of sand, failures occurred under sub-saturated conditions on steep bed slopes (S > 0.5) and under super-saturated conditions at lower slopes. In beds of gravel, however, failures occurred only under super-saturated conditions at all tested slopes, even those approaching the dry angle of repose. Consistent with theoretical models, mass failures under super-saturated conditions initiated along a failure plane approximately one grain-diameter below the bed surface, whereas the failure plane was located near the base of the bed under sub-saturated conditions. However, all experimental beds were more stable than predicted by 1-D infinite-slope stability models. In partially saturated sand, enhanced stability appears to result from suction stress. Enhanced stability in gravel may result from turbulent energy losses in pores or increased granular friction for failures that are shallow with respect to grain size. These grain-size dependent effects are not currently included in stability models for non-cohesive sediment, and they may help to explain better the timing and location of debris flow occurrence.
Transient Heat and Mass Transfer Flow through Salt Water in an Ocean by Inclined Angle
Karim, lfsana; Khan, M. S.; Alam, M. M.; Rouf, M. A.; Ferdows, M.; Tzirtzilakis, E. E.
2016-12-01
In the present computational study, the inclined angle effect of unsteady heat and mass transfer flow through salt water in an ocean was studied. The governing equations together with continuity, momentum, salinity and temperature were developed using the boundary layer approximation. Cartesian coordinate system was introduced to interpret the physical model where x-axis chosen along the direction of salt water flow and y-axis is inclined to x-axis. Two angle of inclination was considered such as 90° and 120°. The time dependent governing equations under the initial and boundary conditions were than transformed into the dimensionless form. A numerical solution approach so-called explicit finite difference method (EFDM) was employed to solve the obtained dimensionless equations. Different physical parameter was found in the model such as Prandtl number, Modified Prandtl number, Grashof number, Heat source parameter and Soret number. A stability and convergence analysis was developed in this study to describe the aspects of the finite difference scheme and this analysis is significant due to accuracy of the EFDM approach. The convergence criteria were observed to be in terms of dimensionless parameter as Pr ≥ 0.0128 and Ps ≥ 0.016. The distributions of the temperature and salinity profiles of salt water flow over different time steps were investigated for the effect of different dimensionless parameters and shown graphically.
Viscous-flow properties and viscosity-average molecular mass of orange peel pectin
Institute of Scientific and Technical Information of China (English)
周尽花; 吴宇雄; 沈志强
2008-01-01
The viscous-flow properties of pectin from the residue of orange peel after extraction of essential oil and flavonoid were studied and the viscosity-average molecular mass(Mv,ave) of this kind of pectin was determined.Experimental results show that Arrhenius viscous-flow equation can be applied to describing the effect of temperature on viscosity of this kind of orange peel pectin solutions with the average viscous-flow activation energy being 17.91 kJ/mol(depending on the concentration).Neither power equation,η =K1 cA1,nor exponential equation,η=K2exp(A2c) can describe the effect of concentration on viscosity of this kind of orange peel pectin solutions well.However,it seems that exponential equation model is more suitable to describe their relation due to its higher linear correlation coefficient.Schulz-Blaschke equation can be used to calculate the intrinsic viscosity of this kind of orange peel pectin.The Mv,ave of the orange peel pectin is 1.65×105 g/mol.
Viscosity parameter in dissipative accretion flows with mass outflow around black holes
Nagarkoti, Shreeram
2016-01-01
Numerical hydrodynamic simulation of inviscid and viscous flows have shown that significant outflows could be produced from the CENtrifugal pressure supported BOundary Layer or CENBOL of an advective disk. However, this barrier is weakened in presence of viscosity, more so, if there are explicit energy dissipations at the boundary layer itself. We study effects of viscosity and energy dissipation theoretically on the outflow rate and show that as the viscosity or energy dissipation (or both) rises, the prospect of formation of outflows is greatly reduced, thereby verifying results obtained through observations and numerical simulations. Indeed, we find that in a dissipative viscous flow, shocks in presence of outflows can be produced only if the Shakura-Sunyaev viscosity parameter {\\alpha} is less than 0.2. This is a direct consequence of modification of the Rankine-Hugoniot relation across the shock in a viscous flow, when the energy dissipation and mass loss in the form of outflows from the post-shock regio...
Directory of Open Access Journals (Sweden)
J.C. Misra
2016-03-01
Full Text Available In the present paper, the problem of oscillatory MHD flow of blood in a porous arteriole in presence of chemical reaction and an external magnetic field has been investigated. Heat and mass transfer during arterial blood flow are also studied. A mathematical model is developed and analyzed by using appropriate mathematical techniques. Expressions for the velocity profile, volumetric flow rate, wall shear stress and rates of heat and mass transfer have been obtained. Variations of the said quantities with different parameters are computed by using MATHEMATICA software. The quantitative estimates are presented through graphs and table.
Moran, Amy L.; Arthur Woods, H.
2010-01-01
BACKGROUND: Many aquatic animals enclose embryos in gelatinous masses, and these embryos rely on diffusion to supply oxygen. Mass structure plays an important role in limiting or facilitating O2 supply, but external factors such as temperature and photosynthesis can play important roles as well. Other external factors are less well understood. METHODOLOGY/PRINCIPAL FINDINGS: We first explored the effects of water flow on O2 levels inside nudibranch embryo masses and compared the effects of fl...
Energy Technology Data Exchange (ETDEWEB)
Huang, Huilian [Food Composition and Methods Development Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD (United States); Key Laboratory of Modern Preparation of TCM, Jiangxi University of Traditional Chinese Medicine, Ministry of Education, Nanchang, Jiangxi Province (China); Sun, Jianghao [Food Composition and Methods Development Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD (United States); McCoy, Joe-Ann [The North Carolina Arboretum Germplasm Repository, UNC Affiliate Campus, Asheville, NC (United States); Zhong, Haiyan [College of Food Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan Province (China); Fletcher, Edward J. [Strategic Sourcing, Inc., Banner Elk, NC 28604 (United States); Harnly, James, E-mail: harnly.james@ars.usda.gov [Food Composition and Methods Development Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD (United States); Chen, Pei, E-mail: pei.chen@ars.usda.gov [Food Composition and Methods Development Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD (United States)
2015-03-01
Flow injection mass spectrometry (FIMS) was used to provide chemical fingerprints of black cohosh (Actaea racemosa L.) in a manner of minutes by omitting the separation step. This method has proven to be a powerful tool for botanical authentication and in this study it was used to distinguish between three Actaea species prior to a more detailed chemical analysis using ultra high-performance liquid chromatography high-resolution mass spectrometry (UHPLC–HRMS). Black cohosh has become increasingly popular as a dietary supplement in the United States for the treatment of symptoms related to menopause. However, it has been known to be adulterated with the Asian Actaea dahurica (Turcz. ex Fisch. & C.A.Mey.) Franch. species (syn. Cimicifuga dahurica (Turcz.) Maxim). Existing methods for identification of black cohosh and differentiation of Actaea species are usually lengthy, laborious, and lack robustness, often based on the comparison of a few pre-selected components. Chemical fingerprints were obtained for 77 black cohosh samples and their related species using FIMS in the negative ion mode. The analysis time for each sample was less than 2 min. All data were processed using principal component analysis (PCA). FIMS fingerprints could readily differentiate all three species. Representative samples from each of the three species were further examined using UHPLC–MS to provide detailed profiles of the chemical differences between the three species and were compared to the PCA loadings. This study demonstrates a simple, fast, and easy analytical method that can be used to differentiate A. racemosa, Actaea podocarpa, and A. dahurica. - Highlights: • Flow injection mass spectrometry (FIMS) was used to provide chemical fingerprints of black cohosh (Actaea racemosa L.) in a manner of minutes by omitting the separation step. • FIMS can discriminate between A. dahurica, A. podocarpa, and A. racemosa. • FIMS is a valuable screening tool for authentication of botanicals.
The Source of Mass Accreted by the Central Black Hole in Cooling Flow Clusters
Soker, N
2006-01-01
This paper reports the study of the cold-feedback heating in cooling flow clusters. In the cold-feedback model the mass accreted by the central black hole originates in non-linear over-dense blobs of gas residing in an extended region (r ~ 5-30 kpc); these blobs are originally hot, but then cool faster than their environment and sink toward the center. The intra-cluster medium (ICM) entropy profile must be shallow for the blobs to reach the center as cold blobs. I build a toy model to explore the role of the entropy profile and the population of dense blobs in the cold-feedback mechanism. The mass accretion rate by the central black hole is determined by the cooling time of the ICM, the entropy profile, and the presence of inhomogeneities. The mass accretion rate determines the energy injected by the black hole back to the ICM. These active galactic nucleus (AGN) outbursts not only heat the ICM, but also change the entropy profile in the cluster and cause inhomogeneities that are the seeds of future dense blo...
Ma, Qiang; Chen, Zhenqian; Liu, Hao
2017-07-01
In this paper, to predict the dynamics behaviors of flow and mass transfer with adsorption phenomena in porous media at the representative elementary volume (REV) scale, a multiple-relaxation-time (MRT) lattice Boltzmann (LB) model for the convection-diffusion equation is developed to solve the transfer problem with an unsteady source term in porous media. Utilizing the Chapman-Enskog analysis, the modified MRT-LB model can recover the macroscopic governing equations at the REV scale. The coupled MRT-LB model for momentum and mass transfer is validated by comparing with the finite-difference method and the analytical solution. Moreover, using the MRT-LB method coupled with the linear driving force model, the fluid transfer and adsorption behaviors of the carbon dioxide in a porous fixed bed are explored. The breakthrough curve of adsorption from MRT-LB simulation is compared with the experimental data and the finite-element solution, and the transient concentration distributions of the carbon dioxide along the porous fixed bed are elaborated upon in detail. In addition, the MRT-LB simulation results show that the appearance time of the breakthrough point in the breakthrough curve is advanced as the mass transfer resistance in the linear driving force model increases; however, the saturation point is prolonged inversely.
Directory of Open Access Journals (Sweden)
Muhammad Zubair Akbar
2016-04-01
Full Text Available The paper presents the numerical study of heat and mass transfer analysis in a viscous unsteady MHD nanofluid flow through a channel with porous walls and medium in the presence of metallic nanoparticles. The two cases for effective thermal conductivity are discussed in the analysis through H-C model. The impacts of the governing parameters on the flow, heat and mass transfer aspects of the issue are talked about. Under the patronage of small values of permeable Reynolds number and relaxation/contraction parameter, we locate that, when wall contraction is together with suction, flow turning is encouraged close to the wall where the boundary layer is shaped. On the other hand, when the wall relaxation is coupled with injection, the flow adjacent to the porous walls decreased. The outcome of the exploration may be beneficial for applications of biotechnology. Numerical solutions for the velocity, heat and mass transfer rate at the boundary are obtained and analyzed.
Nguyen, Thao M; Jingyu Liu; Vincent A. Hackley
2015-01-01
Gold nanorods (GNRs) are of particular interest for biomedical applications due to their unique size-dependent longitudinal surface plasmon resonance band in the visible to near-infrared. Purified GNRs are essential for the advancement of technologies based on these materials. Used in concert, asymmetric-flow field flow fractionation (A4F) and single particle inductively coupled mass spectrometry (spICP-MS) provide unique advantages for fractionating and analyzing the typically complex mixtur...
Flow Boiling Heat Transfer in Two-Phase Micro Channel Heat Sink at Low Water Mass Flux
Kuznetsov, Vladimir V.; Shamirzaev, Alisher S.
2009-08-01
Boiling heat transfer at water flow with low mass flux in heat sink which contained rectangular microchannels was studied. The stainless steel heat sink contained ten parallel microchannels with a size of 640 × 2050 μm in cross-section with typical wall roughness of 10-15 μm. The local flow boiling heat transfer coefficients were measured at mass velocity of 17 and 51 kg/m2s, heat flux on 30 to 150 kW/m2 and vapor quality of up to 0.8 at pressure in the channels closed to atmospheric one. It was observed that Kandlikar nucleate boiling correlation is in good agreement with the experimental data at mass flow velocity of 85 kg/m2s. At smaller mass flux the Kandlikar model and Zhang, Hibiki and Mishima model demonstrate incorrect trend of heat transfer coefficients variation with vapor quality.
Investigation of oil-air two-phase mass flow rate measurement using Venturi and void fraction sensor
Institute of Scientific and Technical Information of China (English)
ZHANG Hong-jian; YUE Wei-ting; HUANG Zhi-yao
2005-01-01
Oil-air two-phase flow measurement was investigated with a Venturi and void fraction meters in this work. This paper proposes a new flow rate measurement correlation in which the effect of the velocity ratio between gas and liquid was considered.With the pressure drop across the Venturi and the void fraction that was measured by electrical capacitance tomography apparatus,both mixture flow rate and oil flow rate could be obtained by the correlation. Experiments included bubble-, slug-, wave and annular flow with the void fraction ranging from 15% to 83%, the oil flow rate ranging from 0.97 kg/s to 1.78 kg/s, the gas flow rate ranging up to 0.018 kg/s and quality ranging nearly up to 2.0%. The root-mean-square errors of mixture mass flow rate and that ofoil mass flow rate were less than 5%. Furthermore, coefficients of the correlation were modified based on flow regimes, with the results showing reduced root-mean-square errors.
Diagonal Slices of 3D Young Diagrams in the Approach of Maya Diagrams
Cai, Li-Qiang; Wang, Li-Fang; Wu, Ke; Yang, Jie
2014-09-01
According to the correspondence between 2D Young diagrams and Maya diagrams and the relation between 2D and 3D Young diagrams, we construct 3D Young diagrams in the approach of Maya diagrams. Moreover, we formulate the generating function of 3D Young diagrams, which is the MacMahon function in terms of Maya diagrams.
Optical Measurement of Mass Flow of a Two-Phase Fluid
Wiley, John; Pedersen, Kevin; Koman, Valentin; Gregory, Don
2008-01-01
An optoelectronic system utilizes wavelength-dependent scattering of light for measuring the density and mass flow of a two-phase fluid in a pipe. The apparatus was invented for original use in measuring the mass flow of a two-phase cryogenic fluid (e.g., liquid hydrogen containing bubbles of hydrogen gas), but underlying principles of operation can readily be adapted to non-cryogenic two-phase fluids. The system (see figure) includes a laser module, which contains two or more laser diodes, each operating at a different wavelength. The laser module also contains beam splitters that combine the beams at the various wavelengths so as to produce two output beams, each containing all of the wavelengths. One of the multiwavelength output beams is sent, via a multimode fiberoptic cable, to a transmitting optical coupler. The other multiwavelength output beam is sent, via another multimode fiber-optic cable, to a reference detector module, wherein fiber-optic splitters split the light into several multiwavelength beams, each going to a photodiode having a spectral response that is known and that differs from the spectral responses of the other photodiodes. The outputs of these photodiodes are digitized and fed to a processor, which executes an algorithm that utilizes the known spectral responses to convert the photodiode outputs to obtain reference laser-power levels for the various wavelengths. The transmitting optical coupler is mounted in (and sealed to) a hole in the pipe and is oriented at a slant with respect to the axis of the pipe. The transmitting optical coupler contains a collimating lens and a cylindrical lens that form the light emerging from the end of the fiber-optic cable into a fan-shaped beam in a meridional plane of the pipe. Receiving optical couplers similar to the transmitting optical couplers are mounted in the same meridional plane at various longitudinal positions on the opposite side of the pipe, approximately facing the transmitting optical
Koku, Harun
Limitations of mass transfer in chromatographic bioseparations employing traditional packed particles have fuelled the inception and development of alternative stationary phases with improved performance characteristics. This work investigates case studies in two categories of these alternative media, namely polymer-modified packed particles and continuous monolithic phases, for insight into their enhanced properties. Specifically, high-resolution microscopy techniques and image-based analysis algorithms were implemented to extract morphology information for these materials, in an attempt to elucidate the relation between microstructure and performance. For the monolith, mesoscopic simulation methods were also employed for a more rigorous analysis of the flow and dispersion behavior. Scanning and transmission electron microscopy images of the commercial polymer-modified, agarose-based particle Sepharose XL were compared to those for its unmodified counterpart, Sepharose FF. Local regions in the composite dextran-agarose Sepharose XL particles were noted to exhibit a denser network of fibers and smaller pore sizes overall, compared to those in the traditional Sepharose FF particles. Images of particles equilibrated with high concentrations of protein revealed a significant difference in protein localization patterns, with the stained protein in XL occupying a markedly higher area fraction of the images. This suggests a higher volume available for adsorption and provides visual clues into how the consistently higher static capacity of these polymer-modified particles is manifested. Treatment of the XL particles with dextranase, an enzyme that breaks down dextran, resulted in a reduction of protein coverage, providing evidence that it is indeed the dextran that is responsible for the improved static capacity in this polymer-modified stationary phase. Imaging and image analysis techniques were also used to analyze the commercial CIM(TM) disk monolith. Two- and three
Flamelet Regime Diagram for Turbulent Combustion Simulations
Chan, Wai Lee; Ihme, Matthias; Kolla, Hemanth; Chen, Jacqueline
2016-11-01
The flamelet model has been widely used in numerical combustion investigations, particularly for the closure of large-eddy simulations (LES) of turbulent reacting flows. In most cases, the simulation results demonstrated good agreements with their experimental counterparts. However, a systematic analysis of the flamelet model's applicability, as well as its potential limitations, is seldom conducted, and the model performance is usually based only on a-posteriori comparisons. The objective of this work is to derive a metric that can formally quantify the suitability of the flamelet model in different flame configurations. For this purpose, a flamelet regime diagram has been developed and studied in the context of direct numerical simulations (DNS) of a turbulent lifted jet flame. The implementation of the regime diagram in LES has been investigated through explicit filtering of the DNS results.
Diagrams and Proofs in Analysis
DEFF Research Database (Denmark)
Carter, Jessica M H Grund
2010-01-01
The article discusses the role of diagrams in mathematical reasoning based on a case study in analysis. In the presented example certain combinatorial expressions were first found by using diagrams. In the published proofs the pictures are replaced by reasoning about permutation groups...
Genus Ranges of Chord Diagrams.
Burns, Jonathan; Jonoska, Nataša; Saito, Masahico
2015-04-01
A chord diagram consists of a circle, called the backbone, with line segments, called chords, whose endpoints are attached to distinct points on the circle. The genus of a chord diagram is the genus of the orientable surface obtained by thickening the backbone to an annulus and attaching bands to the inner boundary circle at the ends of each chord. Variations of this construction are considered here, where bands are possibly attached to the outer boundary circle of the annulus. The genus range of a chord diagram is the genus values over all such variations of surfaces thus obtained from a given chord diagram. Genus ranges of chord diagrams for a fixed number of chords are studied. Integer intervals that can be, and those that cannot be, realized as genus ranges are investigated. Computer calculations are presented, and play a key role in discovering and proving the properties of genus ranges.
DEFF Research Database (Denmark)
Andersen, Jens Enevold Thaulov
The influence of interferences in the analysis of elements by inductively-coupled-plasma mass-spectrometry (ICP-MS) may be significantly diminished by utilising a protocol of flow-injection analysis (FIA). The method is based on filterless preconcentration of metallic elements at the walls...... of a knotted reactor that was made of nylon tubings. In the load mode, the preconcentration was accomplished by precipitation of metallic species in alkaline-buffered carriers onto the inner walls of the hydrofilic tube. After a preconcen-tration period of 40-120 seconds using sample volumes of 4-10 m......L, the analyte was transferred by a FIAS 400 system to the ICP-MS detector by dissolving the species in an acidic carrier. The magnitude of the enrichment factor largely depended on the time of preconcentration, on the pH-value of the preconcentration buffer and on the pH-value of the samples. Enrichment factors...
Heat or mass transfer from a sphere in Stokes flow at low Péclet number
Bell, Christopher G.
2013-04-01
We consider the low Péclet number, Pe≪1, asymptotic solution for steady-state heat or mass transfer from a sphere immersed in Stokes flow with a Robin boundary condition on its surface, representing Newton cooling or a first-order chemical reaction. The application of Van Dyke\\'s rule up to terms of O(Pe3) shows that the O(Pe3logPe) terms in the expression for the average Nusselt/Sherwood number are twice those previously derived in the literature. Inclusion of the O(Pe3) terms is shown to increase the range of validity of the expansion. © 2012 Elsevier Ltd. All rights reserved.
Enot, David P; Lin, Wanchang; Beckmann, Manfred; Parker, David; Overy, David P; Draper, John
2008-01-01
Metabolome analysis by flow injection electrospray mass spectrometry (FIE-MS) fingerprinting generates measurements relating to large numbers of m/z signals. Such data sets often exhibit high variance with a paucity of replicates, thus providing a challenge for data mining. We describe data preprocessing and modeling methods that have proved reliable in projects involving samples from a range of organisms. The protocols interact with software resources specifically for metabolomics provided in a Web-accessible data analysis package FIEmspro (http://users.aber.ac.uk/jhd) written in the R environment and requiring a moderate knowledge of R command-line usage. Specific emphasis is placed on describing the outcome of modeling experiments using FIE-MS data that require further preprocessing to improve quality. The salient features of both poor and robust (i.e., highly generalizable) multivariate models are outlined together with advice on validating classifiers and avoiding false discovery when seeking explanatory variables.
Li, Fu-An; Huang, Ju-Li; Shen, Shang-Yu; Wang, Che-Wei; Her, Guor-Rong
2009-04-01
To alleviate ion suppression from phosphate buffer and to preserve separation integrity, a new capillary electrophoresis mass spectrometry (CE-MS) interface was developed. The interface consisted of a low-flow interface and a liquid junction. In this design, both the inlet reservoir and the liquid-junction reservoir were filled with phosphate running buffer. Because the phosphate anions in the column migrated toward the inlet reservoir (away from the electrospray ionization (ESI) source) the problem of ion suppression in ESI was avoided. The liquid junction was incorporated to eliminate issues of degraded separation observed when sheath liquid interfaces use different buffers for separation and MS analysis attributed to differences in anion velocity. The utility of the interface was demonstrated by the analysis of antihistamines at pH 3.5 and the analysis of perfluorocarboxylic acid at pH 9.5.
Wang, Li Kun; Heng, Paul Wan Sia; Liew, Celine Valeria
2010-08-16
The primary purpose of this study is to develop a visiometric process analyzer for online monitoring of particle mass flow rate in the bottom spray fluid bed coating process. The secondary purpose is to investigate the influences of partition gap and air accelerator insert size on particle mass flow rate using the developed visiometric process analyzer. Particle movement in the region between the product chamber and partition column was captured using a high speed camera. Mean particle velocity and number of particles in the images were determined by particle image velocimetry and morphological image processing method respectively. Mass flow rate was calculated using particle velocity, number of particles in the images, particle density and size information. Particle velocity and number findings were validated using image tracking and manual particle counting techniques respectively. Validation experiments showed that the proposed method was accurate. Partition gap was found to influence particle mass flow rate by limiting the rate of solids flux into the partition column; the air accelerator insert was found to influence particle mass flow rate by a Venturi effect. Partition gap and air accelerator insert diameter needed to be adjusted accordingly in relation to the other variability sources and diameter of coating cores respectively. The potential, challenges and possible solutions of the proposed visiometric process analyzer were further discussed. Copyright (c) 2010 Elsevier B.V. All rights reserved.
Institute of Scientific and Technical Information of China (English)
张强; 吴少玮; 方鹏骞
2012-01-01
Objective: Analyzing and classifying the factors which affect the human resources' flow, then provide some suggestions to steady the human resources. Methods: By literature analysis, collecting the literature about human resources flow and analyzing the factor of human resources' flow in community health service institutions by fish bone diagram. Results: The factors which affect the stability of human resources in community health service institution could be divided into social factors, organizational factors and personal factors. Conclusion: Effects of the human resources's flow in community health service institutions:social factors, government investment for community health service institutions was not full, security system was not perfect; organizational factors, such as incentive management system, promotion system are not perfect; personal factors such as age, gender, profession, education, job title and so on. Suggestions: In order to steady the human resources in community health service institution, increase the reasonable input to community health service; give the right to community health service institutions for choosing the right person to work; raise the income level; establish a reasonable system of personnel training and a rational system for health staffs title promotion; implement the flexible management to the staff in community health service institutions.%目的:通过对影响社区卫生人力流动的影响因素进行分析,提出稳定社区卫生人力的建议.方法:通过个人访谈和文献查阅收集资料,运用鱼骨图分析法,对于我国社区卫生人力资源流动的影响因素进行分析.结果:影响社区卫生人力资源流动的影响因素可以分为社会因素、组织因素和个人因素3部分.结论:影响我国社区人力资源流动的影响因素有以下几个方面:社会因素方面,政府投入不足,保障制度不健全；机构层面,管理制度如激励机制、晋升制度不健全；
Ezzedine, S. M.
2010-12-01
Fractures and fracture networks are the principle pathways for migration of water, heat and mass in enhanced geothermal systems, oil and gas reservoirs, CO2 leakage from saline aquifers, and radioactive and toxic industrial wastes from underground storage repositories. A major issue to overcome when characterizing a fractured reservoir is that of data limitation due to accessibility and affordability. Moreover, the ability to map discontinuities in the rock with available geological and geophysical tools tends to decrease particularly as the scale of the discontinuity goes down. Geological characterization data include measurements of fracture density, orientation, extent, and aperture, and are based on analysis of outcrops, borehole optical and acoustic televiewer logs, aerial photographs, and core samples among others. All of these measurements are taken at the field scale through a very sparse limited number of deep boreholes. These types of data are often reduced to probability distributions function for predictive modeling and simulation in a stochastic framework such as stochastic discrete fracture network. Stochastic discrete fracture network models enable, through Monte Carlo realizations and simulations, for probabilistic assessment of flow and transport phenomena that are not adequately captured using continuum models. Despite the fundamental uncertainties inherited within the probabilistic reduction of the sparse data collected, very little work has been conducted on quantifying uncertainty on the reduced probabilistic distribution functions. In the current study, using nested Monte Carlo simulations, we present the impact of parameter uncertainties of the distribution functions that characterize discrete fracture networks on the flow, heat and mass transport. Numerical results of first, second and third moments, normalized to a base case scenario, are presented and compared to theoretical results extended from percolation theory.
Quantitative Assessment of Mass Flow Boundaries in Continuous Twin-screw Granulation.
Schmidt, Adrian; de Waard, Hans; Moll, Klaus-Peter; Krumme, Markus; Kleinebudde, Peter
2016-01-01
In pharmaceutical manufacturing, there is an increasing interest in continuous manufacturing. As an example for fast continuous processes in general of considerable complexity, this study was focussed on improving the understanding of twin-screw wet granulation. The impact of the liquid-to-solid (L/S) mass flow ratio on product quality (granules) as well as on downstream process operations (tableting) was investigated in detail. Initially two methods were used to define L/S ratio boundaries for the granulation regime in twin-screw wet granulation. It was shown that the first method, which is based on measuring the wet granule mass flow variation, can be used to define the upper L/S ratio boundary of the granulation regime. The second method, based on measuring the granule size distribution, can be used to define the lower L/S ratio boundary of the regime. Using these methods, the granulation regime for different formulations could be established. This information was then used to show that the formulation could be optimised such that the process is more robust (i.e. wider L/S ratio boundaries for the granulation regime). Also it could be used to optimise the formulation considering further downstream processing such as drying (using as little water as possible to reduce drying efforts) or tableting (obtain granules with optimised tableting properties). Preferably, the process should be performed close to the lower L/S ratio boundary of the granulation regime. In summary, these tools enabled the quantitative establishment of granulation regime boundaries in a twin-screw wet granulation process and can be used to optimise formulation and to create a robust process. Analogies to other continuous processes in completely different applications can be conceived.
Importance of Added Mass and Damping in Flow-Induced Vibration Analysis of Tubes Bundle: An Overview
Directory of Open Access Journals (Sweden)
Faisal Karim Shami
2012-01-01
Full Text Available Flow-induced vibration is of prime concern to the designers of heat exchangers subjected to high flows of gases or liquids. Excessive vibration may cause tube failure due to fatigue or fretting-wear. Tube failure results in, expensive plant upholding and suffers loss of production. Therefore, tube failure due to unwarranted vibration must be avoided in process heat exchangers and nuclear steam generators, preferably at design stage. Such vibration problems may be avoided through a comprehensive flowinduced vibration analysis before fabrication of heat exchangers. However, it requires an understanding of vibration mechanism and parameters related to flow-induced vibration. For an accurate vibration analysis, it is of prime importance to have good estimates of structural and flow related dynamic parameters. Thus dynamic parameters such as added mass and damping are of significant concern in a flow regime. The purpose of this paper is to provide an overview of our state of knowledge and role of dynamic parameters in flow-induced vibration on tube bundles due to current trend of larger heat exchangers. The present paper provides published data, analysis, evaluation, formulation, and experimental studies related to hydrodynamic mass and damping by a large number of researchers. Guidelines for experimental research and heat exchangers design related to added mass and damping mechanisms subjected to both single and two-phase flow are outlined in this paper.
A simple, mass balance model of carbon flow in a controlled ecological life support system
Garland, Jay L.
1989-01-01
Internal cycling of chemical elements is a fundamental aspect of a Controlled Ecological Life Support System (CELSS). Mathematical models are useful tools for evaluating fluxes and reservoirs of elements associated with potential CELSS configurations. A simple mass balance model of carbon flow in CELSS was developed based on data from the CELSS Breadboard project at Kennedy Space Center. All carbon reservoirs and fluxes were calculated based on steady state conditions and modelled using linear, donor-controlled transfer coefficients. The linear expression of photosynthetic flux was replaced with Michaelis-Menten kinetics based on dynamical analysis of the model which found that the latter produced more adequate model output. Sensitivity analysis of the model indicated that accurate determination of the maximum rate of gross primary production is critical to the development of an accurate model of carbon flow. Atmospheric carbon dioxide was particularly sensitive to changes in photosynthetic rate. The small reservoir of CO2 relative to large CO2 fluxes increases the potential for volatility in CO2 concentration. Feedback control mechanisms regulating CO2 concentration will probably be necessary in a CELSS to reduce this system instability.
Pinsker estimators for local helioseismology: inversion of travel times for mass-conserving flows
Fournier, Damien; Gizon, Laurent; Holzke, Martin; Hohage, Thorsten
2016-10-01
A major goal of helioseismology is the three-dimensional reconstruction of the three velocity components of convective flows in the solar interior from sets of wave travel-time measurements. For small amplitude flows, the forward problem is described in good approximation by a large system of convolution equations. The input observations are highly noisy random vectors with a known dense covariance matrix. This leads to a large statistical linear inverse problem. Whereas for deterministic linear inverse problems several computationally efficient minimax optimal regularization methods exist, only one minimax-optimal linear estimator exists for statistical linear inverse problems: the Pinsker estimator. However, it is often computationally inefficient because it requires a singular value decomposition of the forward operator or it is not applicable because of an unknown noise covariance matrix, so it is rarely used for real-world problems. These limitations do not apply in helioseismology. We present a simplified proof of the optimality properties of the Pinsker estimator and show that it yields significantly better reconstructions than traditional inversion methods used in helioseismology, i.e. regularized least squares (Tikhonov regularization) and SOLA (approximate inverse) methods. Moreover, we discuss the incorporation of the mass conservation constraint in the Pinsker scheme using staggered grids. With this improvement we can reconstruct not only horizontal, but also vertical velocity components that are much smaller in amplitude.
Turbulent heat-and-mass transfer in channel flow at transcritical temperature conditions
Kim, Kukjin; Scalo, Carlo; Hickey, Jean-Pierre
2016-11-01
Turbulent heat and mass transfer at transcritical thermodynamic conditions is studied in turbulent channel flow using the high-fidelity DNS for solution to the compressible Navier-Stokes equations in the conservative form closed with the Peng-Robinson state equation. To isolate the real fluid effects on turbulent heat transfer, the bulk pressure is maintained at supercritical pb = 1 . 1pc and the isothermal walls are set to ΔT / 2 above and below the local pseudo-boiling temperature Tpb of the fluid (R-134a) where ΔT is 5K, 10K, and 20K. This setup allows the flow to reach a statistically-steady state while capturing the highest thermodynamic gradients, thus allowing a detailed study on thermodynamics of transcritical turbulent heat transfer. All thermodynamic and turbulent scales are fully resolved which is shown through a careful grid convergence analysis. The time-averaged density and compressibility factor are highly dependent on the temperature field and their large near-wall gradient causes thermodynamically-induced peaks in the RMS quantities resulting in strong turbulent mixing. The ejection of heavy pseudo-liquid blobs by near-wall turbulent structures into the channel core leads to a third RMS peak which is not observable in ideal gas simulations.
Cuts and coproducts of massive triangle diagrams
Energy Technology Data Exchange (ETDEWEB)
Abreu, Samuel [Higgs Centre for Theoretical Physics, School of Physics and Astronomy,The University of Edinburgh,Mayfield Road, Edinburgh EH9 3JZ, Scotland (United Kingdom); Institut de Physique Théorique, Université Paris Saclay, CEA, CNRS,Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Britto, Ruth [Institut de Physique Théorique, Université Paris Saclay, CEA, CNRS,Orme des Merisiers, F-91191 Gif-sur-Yvette (France); School of Mathematics, Trinity College,College Green, Dublin 2 (Ireland); Hamilton Mathematical Institute, Trinity College,College Green, Dublin 2 (Ireland); Grönqvist, Hanna [Institut de Physique Théorique, Université Paris Saclay, CEA, CNRS,Orme des Merisiers, F-91191 Gif-sur-Yvette (France)
2015-07-21
Relations between multiple unitarity cuts and coproducts of Feynman integrals are extended to allow for internal masses. These masses introduce new branch cuts, whose discontinuities can be derived by placing single propagators on shell and identified as particular entries of the coproduct. First entries of the coproduct are then seen to include mass invariants alone, as well as threshold corrections for external momentum channels. As in the massless case, the original integral can possibly be recovered from its cuts by starting with the known part of the coproduct and imposing integrability contraints. We formulate precise rules for cuts of diagrams, and we gather evidence for the relations to coproducts through a detailed study of one-loop triangle integrals with various combinations of external and internal masses.
Qiao, Jixin; Hou, Xiaolin; Steier, Peter; Nielsen, Sven; Golser, Robin
2015-07-21
An automated analytical method implemented in a flow injection (FI) system was developed for rapid determination of (236)U in 10 L seawater samples. (238)U was used as a chemical yield tracer for the whole procedure, in which extraction chromatography (UTEVA) was exploited to purify uranium, after an effective iron hydroxide coprecipitation. Accelerator mass spectrometry (AMS) was applied for quantifying the (236)U/(238)U ratio, and inductively coupled plasma mass spectrometry (ICPMS) was used to determine the absolute concentration of (238)U; thus, the concentration of (236)U can be calculated. The key experimental parameters affecting the analytical effectiveness were investigated and optimized in order to achieve high chemical yields and simple and rapid analysis as well as low procedure background. Besides, the operational conditions for the target preparation prior to the AMS measurement were optimized, on the basis of studying the coprecipitation behavior of uranium with iron hydroxide. The analytical results indicate that the developed method is simple and robust, providing satisfactory chemical yields (80-100%) and high analysis speed (4 h/sample), which could be an appealing alternative to conventional manual methods for (236)U determination in its tracer application.
Sun, G; Austin, D
2007-01-01
A laboratory-scale, mass-balance study was carried out on the transformation of nitrogenous pollutants in four vertical flow wetland columns. Landfill leachate containing low organic matter, but a high concentration of ammoniacal-nitrogen, was treated under dissolved oxygen concentrations close to saturation. Influent total nitrogen (TN) comprised ammoniacal-nitrogen with less than 1% nitrate and nitrite, negligible organic nitrogen, and very low BOD. Nitrification occurred in three of the four columns. There was a substantial loss of total nitrogen (52%) in one column, whereas other columns exhibited zero to minor losses (< 12%). Nitrogen loss under study conditions was unexpected. Two hypotheses are proposed to account for it: (1) either the loss of TN is attributed to nitrogen transformation into a form (provisionally termed alpha-nitrogen) that is undetectable by the analytical methods used; or (2) the loss is caused by microbial denitrification or deammonification. By elimination and stoichiometric mass balance calculations, completely autotrophic nitrogen-removal over nitrite (CANON) deammonification is confirmed as responsible for nitrogen loss in one column. This result reveals that CANON can be native to aerobic engineered wetland systems treating high ammonia, low organic content wastewater.
Parsec-scale X-ray Flows in High-mass Star-forming Regions
Townsley, L K; Montmerle, T; Broos, P; Chu, Y H; Garmire, G; Getman, K
2004-01-01
We present Chandra/ACIS images of several high-mass star-forming regions. The massive stellar clusters powering these HII regions are resolved at the arcsecond level into hundreds of stellar sources, similar to those seen in closer young stellar clusters. However, we also detect diffuse X-ray emission on parsec scales that is spatially and spectrally distinct from the point source population. For nearby regions (e.g. M17 and Rosette) the emission is soft, with plasma temperatures less than 10 million degrees, in contrast to what is seen in more distant complexes (e.g. RCW49, W51). This extended emission most likely arises from the fast O-star winds thermalized either by wind-wind collisions or by a termination shock against the surrounding media. We have established that only a small portion of the wind energy and mass appears in the observed diffuse X-ray plasma; in the blister HII regions, we suspect that most of it flows without cooling into the low-density interstellar medium through blow-outs or fissures...
IUE spectroscopy of U Cephei during the mass flow outburst of 1986 June
Mccluskey, George E., Jr.; Kondo, Yoji; Olson, Edward C.
1988-01-01
The interacting Algol-type binary U Cep underwent another of its irregularly occurring transient high-mass flow events during June 1986. For the first time, high-resolution ultraviolet spectroscopy of U Cep during such an event was possible. High-resolution spectra in the far-ultraviolet and near-ultraviolet were obtained with IUE. These spectra show that the ultraviolet continuum decreased by factors of 1.2 to 3.0 during the greatest activity. In addition, one or more narrow absorption components with radial velocities as high as -500 km/s appeared in association with a number of C, Si, Al, Fe, Zn, and Mg lines. The Mg II doublet developed a flat-bottomed appearance with a residual intensity of about 0.31 and a width of at least 800 km/s. These phenomena are interpreted in terms of high-velocity gas streams, mass loss from the system, and the formation of an optically thick equatorial bulge around the B star.
Mass transport aspects of polymer electrolyte fuel cells under two-phase flow conditions
Energy Technology Data Exchange (ETDEWEB)
Kramer, D.
2007-03-27
This work deals with selected aspects of mass transport phenomena in PEFCs and DMFCs. Emphasis is placed on the implications originating from the occurrence of two-phase flow within these devices. Optimality of supply, distribution, and removal of the fuel, the oxidant, and the reaction products is of utmost importance for the stability, efficiency, and durability of the devices. Being a prerequisite for high current densities while maintaining sufficient voltage, mass transport optimization contributes to the development of cost effective as well as compact designs and hence competitive fuel cells. [German] Die Visualisierung und Quantifizierung von Fluessigwasseransammlungen in Polymerelektrolytmembran-Brennstoffzellen konnte mittels Neutronenradiographie erreicht werden. Dank dieser neuartigen diagnostischen Methode konnte erstmals die Fluessigwasseransammlung in den poroesen Gasdiffusionsschichten direkt nachgewiesen und quantifiziert werden. Die Kombination von Neutronenradiographie mit ortsaufgeloesten Stromdichtemessungen bzw. lokaler Impedanzspektroskopie erlaubte die Korrelation des inhomogenen Fluessigwasseranfalls mit dem lokalen elektrochemischen Leistungsverhalten. Systematische Untersuchungen an Polymerelektrolyt- und Direkt-Methanol-Brennstoffzellen verdeutlichen sowohl den Einfluss von Betriebsbedingungen als auch die Auswirkung von Materialeigenschaften auf die Ausbildung zweiphasiger Stroemungen.
Selenium removal and mass balance in a constructed flow-through wetland system.
Gao, S; Tanji, K K; Lin, Z Q; Terry, N; Peters, D W
2003-01-01
A field study on the removal of Se from agricultural subsurface drainage was conducted from May 1997 to February 2001 in the Tulare Lake Drainage District (TLDD) of San Joaquin Valley, California. A flow-through wetland system was constructed consisting of ten 15- x 76-m unlined cells that were continuously flooded and planted with either a monotype or combination of plants, including sturdy bulrush [Schoenoplectus robustus (Pursh) M.T. Strong], baltic rush (Juncus balticus Willd.), smooth cordgrass (Spartina alterniflora Loisel.), rabbitsfoot grass [Polypogon monspeliensis (L.) Desf.], salt-grass lDistichlis spicata (L.) Greene], cattail (Typha latifolia L.), tule [Schoenoplectus acutus (Muhl. ex Bigelow) A. Löve & D. Löve], and widgeon grass (Ruppia maritima L.). One cell had no vegetation planted. The objectives of this research were to evaluate Se removal efficiency of each wetland cell and to carry out a mass balance on Se. The inflow drainage water to the cells had average annual Se concentrations of 19 to 22 microg L(-1) dominated by selenate [Se(VI), 95%]. Average weekly water residence time varied from about 3 to 15 d for Cells 1 through 7 (target 7 d), 19 to 33 d for Cells 8 and 9 (target 21 d), and 13 to 18 d for Cell 10 (target 14 d). Average weekly Se concentration ratios of outflow to inflow ranged from 0.45 to 0.79 and mass ratio (concentration x water volume) from 0.24 to 0.52 for year 2000, that is, 21 to 55% reduction in Se concentration and 48 to 76% Se removal in mass by the wetland, respectively. The nonvegetated cell showed the least Se removal both in concentration and in mass. The global mass balance showed that on the average about 59% of the total inflow Se was retained within the cells and Se outputs were outflow (35%), seepage (4%), and volatilization (2%). Independent measurements of the Se retained in the cells totaled 53% of the total Se inflow: 33% in the surface (0-20 cm) sediment, 18% in the organic detrital layer above the
Emerging flow injection mass spectrometry methods for high-throughput quantitative analysis.
Nanita, Sergio C; Kaldon, Laura G
2016-01-01
Where does flow injection analysis mass spectrometry (FIA-MS) stand relative to ambient mass spectrometry (MS) and chromatography-MS? Improvements in FIA-MS methods have resulted in fast-expanding uses of this technique. Key advantages of FIA-MS over chromatography-MS are fast analysis (typical run time quantitative screening of chemicals needs to be performed rapidly and reliably. The FIA-MS methods discussed herein have demonstrated quantitation of diverse analytes, including pharmaceuticals, pesticides, environmental contaminants, and endogenous compounds, at levels ranging from parts-per-billion (ppb) to parts-per-million (ppm) in very complex matrices (such as blood, urine, and a variety of foods of plant and animal origin), allowing successful applications of the technique in clinical diagnostics, metabolomics, environmental sciences, toxicology, and detection of adulterated/counterfeited goods. The recent boom in applications of FIA-MS for high-throughput quantitative analysis has been driven in part by (1) the continuous improvements in sensitivity and selectivity of MS instrumentation, (2) the introduction of novel sample preparation procedures compatible with standalone mass spectrometric analysis such as salting out assisted liquid-liquid extraction (SALLE) with volatile solutes and NH4(+) QuEChERS, and (3) the need to improve efficiency of laboratories to satisfy increasing analytical demand while lowering operational cost. The advantages and drawbacks of quantitative analysis by FIA-MS are discussed in comparison to chromatography-MS and ambient MS (e.g., DESI, LAESI, DART). Generally, FIA-MS sits 'in the middle' between ambient MS and chromatography-MS, offering a balance between analytical capability and sample analysis throughput suitable for broad applications in life sciences, agricultural chemistry, consumer safety, and beyond.
MASS TRANSFER CONTROL OF A BACKWARD-FACING STEP FLOW BY LOCAL FORCING- EFFECT OF REYNOLDS NUMBER
Directory of Open Access Journals (Sweden)
Zouhaier MEHREZ
2011-01-01
Full Text Available The control of fluid mechanics and mass transfer in separated and reattaching flow over a backward-facing step by a local forcing, is studied using Large Eddy Simulation (LES.To control the flow, the local forcing is realized by a sinusoidal oscillating jet at the step edge. The Reynolds number is varied in the range 10000 ≤ Re≤ 50000 and the Schmidt number is fixed at 1.The found results show that the flow structure is modified and the local mass transfer is enhanced by the applied forcing. The observed changes depend on the Reynolds number and vary with the frequency and amplitude of the local forcing. For the all Reynolds numbers, the largest recirculation zone size reduction is obtained at the optimum forcing frequency St = 0.25. At this frequency the local mass transfer enhancement attains the maximum.
Wang, Yi
2017-09-12
Reduced-order modeling approaches for gas flow in dual-porosity dual-permeability porous media are studied based on the proper orthogonal decomposition (POD) method combined with Galerkin projection. The typical modeling approach for non-porous-medium liquid flow problems is not appropriate for this compressible gas flow in a dual-continuum porous media. The reason is that non-zero mass transfer for the dual-continuum system can be generated artificially via the typical POD projection, violating the mass-conservation nature and causing the failure of the POD modeling. A new POD modeling approach is proposed considering the mass conservation of the whole matrix fracture system. Computation can be accelerated as much as 720 times with high precision (reconstruction errors as slow as 7.69 × 10−4%~3.87% for the matrix and 8.27 × 10−4%~2.84% for the fracture).
Directory of Open Access Journals (Sweden)
S. S. Das, S. Parija, R. K. Padhy, M. Sahu
2012-01-01
Full Text Available This paper investigates the natural convection unsteady magnetohydrodynamic mass transfer flow of a viscous incompressible electrically conducting fluid past an infinite vertical porous flat plate in presence of constant suction and heat sink. Using multi parameter perturbation technique, the governing equations of the flow field are solved and approximate solutions are obtained. The effects of the flow parameters on the velocity, temperature, concentration distribution and also on the skin friction and rate of heat transfer are discussed with the help of figures and table. It is observed that a growing magnetic parameter or Schmidt number or heat sink parameter leads to retard the transient velocity of the flow field at all points, while the Grashof numbers for heat and mass transfer show the reverse effect. It is further found that a growing Prandtl number or heat sink parameter decreases the transient temperature of the flow field at all points while the heat source parameter reverses the effect. The concentration distribution of the flow field suffers a decrease in boundary layer thickness in presence of heavier diffusive species (growing Sc at all points of the flow field. The effect of increasing Prandtl number Pr is to decrease the magnitude of skin-friction and to increase the rate of heat transfer at the wall for MHD flow, while the effect of increasing magnetic parameter M is to decrease their values at all points.
New considerations on the mass and energy balances in one-dimensional two-phase flow at steady state
Energy Technology Data Exchange (ETDEWEB)
Collado, F.J. [Zaragoza Univ. (Spain). Dept. de Ingenieria Mecanica; Munoz, M. [Zaragoza Univ. (Spain). Dept. de Ingenieria Mecanica
1997-08-01
A new equation to be added to the classical mass balance expressions for two-phase flow is presented. It is based on the definition of new differential control volumes of variable length which are proportional to the gas velocity in a compressible flow. The new equation is equivalent to the gas-solids velocity ratio being constant throughout the duct, and it is used to derive a new expression of the energy balance for a two-phase, non-reacting flow. Through this energy balance, new correlations for the pressure drop in pneumatic conveying lines are obtained, showing an excellent agreement with experimental data from the high-pressure research facility of the Institute of Gas Technology, Chicago, IL. Finally, a more general equation, which is also valid for the mass balance of reacting flows, is supplied. (orig.)
Institute of Scientific and Technical Information of China (English)
LI Yang; ZHENG Ying-na; YUE Hong-wei
2005-01-01
The fan-beam optical sensor is made up of many semiconductor lasers and detectors fixed around the wall alternately at a cross section of pneumatically conveying pipe. When the sensor works, a scanning light source emits a 50° lamellar fan-beam through the gas-solid two phase flow, and the projection data resulting extinction effect of solid particles are detected at the same time. With the projection data, the flow rate mass can be calculated, and then the flow image can be reconstructed. In this paper, the design of the sensor including spatial arrangement of the structural parts, basic principle and measurement sensitivity distribution are introduced. The mathematical measurement model of solid mass flow rate is presented together with the testing results.
The Genesis of Feynman Diagrams
Wuthrich, Adrian
2011-01-01
In a detailed reconstruction of the genesis of Feynman diagrams the author reveals that their development was constantly driven by the attempt to resolve fundamental problems concerning the uninterpretable infinities that arose in quantum as well as classical theories of electrodynamic phenomena. Accordingly, as a comparison with the graphical representations that were in use before Feynman diagrams shows, the resulting theory of quantum electrodynamics, featuring Feynman diagrams, differed significantly from earlier versions of the theory in the way in which the relevant phenomena were concep
Farthest-Polygon Voronoi Diagrams
Cheong, Otfried; Glisse, Marc; Gudmundsson, Joachim; Hornus, Samuel; Lazard, Sylvain; Lee, Mira; Na, Hyeon-Suk
2010-01-01
Given a family of k disjoint connected polygonal sites in general position and of total complexity n, we consider the farthest-site Voronoi diagram of these sites, where the distance to a site is the distance to a closest point on it. We show that the complexity of this diagram is O(n), and give an O(n log^3 n) time algorithm to compute it. We also prove a number of structural properties of this diagram. In particular, a Voronoi region may consist of k-1 connected components, but if one component is bounded, then it is equal to the entire region.
Scattering equations and Feynman diagrams
Baadsgaard, Christian; Bjerrum-Bohr, N. E. J.; Bourjaily, Jacob L.; Damgaard, Poul H.
2015-09-01
We show a direct matching between individual Feynman diagrams and integration measures in the scattering equation formalism of Cachazo, He and Yuan. The connection is most easily explained in terms of triangular graphs associated with planar Feynman diagrams in φ 3-theory. We also discuss the generalization to general scalar field theories with φ p interactions, corresponding to polygonal graphs involving vertices of order p. Finally, we describe how the same graph-theoretic language can be used to provide the precise link between individual Feynman diagrams and string theory integrands.
Scattering Equations and Feynman Diagrams
Baadsgaard, Christian; Bourjaily, Jacob L; Damgaard, Poul H
2015-01-01
We show a direct matching between individual Feynman diagrams and integration measures in the scattering equation formalism of Cachazo, He and Yuan. The connection is most easily explained in terms of triangular graphs associated with planar Feynman diagrams in $\\phi^3$-theory. We also discuss the generalization to general scalar field theories with $\\phi^p$ interactions, corresponding to polygonal graphs involving vertices of order $p$. Finally, we describe how the same graph-theoretic language can be used to provide the precise link between individual Feynman diagrams and string theory integrands.
零净质量射流的数值模拟%Numerical simulation of the zero mass jet flow
Institute of Scientific and Technical Information of China (English)
石清; 李桦
2011-01-01
对零净质量射流致动器的流场和有零净质量射流时翼型的绕流流场进行了数值模拟,分析了动网格与几何守恒率、边界条件、湍流模型对零净质量射流致动器流场计算的影响,分析了零净质量射流的速度幅值和驱动频率对翼型增升效果的影响.研究结果表明,在复杂计算中可以对能动部件的边界作赋值处理;随着射流速度幅值的增加,翼型的平均升力系数和阻力系数都要增加;射流频率对升力的影响呈非线性.%Numerical simulation methods are used to investigate the actuator of zero mass jet flow and the flow around airfoil with zero mass jet flow.The effects on the actuator of zero mass jet flow are analysed about dynamic grid,geometry conservation law, numerical boundary conditions, and turbulence mode.And the effects on increasing lift are analysed also, including the jet flow velocity and frequency.The results indicate that numerical boundary conditions of the actuator of zero mass jet flow can be treated with given numerical value for complicated calculation, both the average lift coefficient and the average drag coefficient are added with the increase of the jet flow velocity, and the effects of the jet flow frequency on lift are non - linear.
Palhares, Letícia F
2008-01-01
Yukawa theory at vanishing temperature provides (one of the ingredients for) an effective description of the thermodynamics of a variety of cold and dense fermionic systems. We study the role of masses and the renormalization group flow in the calculation of the equation of state up to two loops within the MSbar scheme. Two-loop integrals are computed analytically for arbitrary fermion and scalar masses, and expressed in terms of well-known special functions. The dependence of the renormalization group flow on the number of fermion flavors is also discussed.
Veera Krishna, M.; Swarnalathamma, B. V.
2016-05-01
In this paper, we discussed the peristaltic MHD flow of an incompressible and electrically conducting Williamson fluid in a symmetric planar channel with heat and mass transfer under the effect of inclined magnetic field. Viscous dissipation and Joule heating are also taken into consideration. Mathematical model is presented by using the long wavelength and low Reynolds number approximations. The differential equations governing the flow are highly nonlinear and thus perturbation solution for small Weissenberg number (We Effects of the heat and mass transfer on the longitudinal velocity, temperature and concentration are studied in detail. Main observations are presented in the concluding section. The streamlines pattern is also given due attention.
Waythomas, C.F.; Wallace, K.L.
2002-01-01
An areally extensive volcanic mass-flow deposit of Pleistocene age, known as the Chetaslina volcanic mass-flow deposit, is a prominent and visually striking deposit in the southeastern Copper River lowland of south-central Alaska. The mass-flow deposit consists of a diverse mixture of colorful, variably altered volcanic rocks, lahar deposits, glaciolacustrine diamicton, and till that record a major flank collapse on the southwest flank of Mount Wrangell. The deposit is well exposed near its presumed source, and thick, continuous, stratigraphic exposures have permitted us to study its sedimentary characteristics as a means of better understanding the origin, significance, and evolution of the deposit. Deposits of the Chetaslina volcanic mass flow in the Chetaslina River drainage are primary debris-avalanche deposits and consist of two principal facies types, a near-source block facies and a distal mixed facies. The block facies is composed entirely of block-supported, shattered and fractured blocks with individual blocks up to 40 m in diameter. The mixed facies consists of block-sized particles in a matrix of poorly sorted rock rubble, sand, and silt generated by the comminution of larger blocks. Deposits of the Chetaslina volcanic mass flow exposed along the Copper, Tonsina, and Chitina rivers are debris-flow deposits that evolved from the debris-avalanche component of the flow and from erosion and entrainment of local glacial and glaciolacustrine diamicton in the Copper River lowland. The debris-flow deposits were probably generated through mixing of the distal debris avalanche with the ancestral Copper River, or through breaching of a debris-avalanche dam across the ancestral river. The distribution of facies types and major-element chemistry of clasts in the deposit indicate that its source was an ancestral volcanic edifice, informally known as the Chetaslina vent, on the southwest side of Mount Wrangell. A major sector collapse of the Chetaslina vent initiated
Nishizaki, Michael T; Carrington, Emily
2014-06-15
In aquatic systems, physiological processes such as respiration, photosynthesis and calcification are potentially limited by the exchange of dissolved materials between organisms and their environment. The nature and extent of physiological limitation is, therefore, likely to be dependent on environmental conditions. Here, we assessed the metabolic sensitivity of barnacles under a range of water temperatures and velocities, two factors that influence their distribution. Respiration rates increased in response to changes in temperature and flow, with an interaction where flow had less influence on respiration at low temperatures, and a much larger effect at high temperatures. Model analysis suggested that respiration is mass transfer limited under conditions of low velocity (mass transfer and kinetic limitation are important. Behavioral monitoring revealed that barnacles fully extend their cirral appendages at low flows and display abbreviated 'testing' behaviors at high flows, suggesting some form of mechanical limitation. In low flow-high temperature treatments, however, barnacles displayed distinct 'pumping' behaviors that may serve to increase ventilation. Our results suggest that in slow-moving waters, respiration may become mass transfer limited as temperatures rise, whereas faster flows may serve to ameliorate the effects of elevated temperatures. Moreover, these results underscore the necessity for approaches that evaluate the combined effects of multiple environmental factors when examining physiological and behavioral performance.
Large-eddy simulation of high-Schmidt number mass transfer in a turbulent channel flow
Calmet, Isabelle; Magnaudet, Jacques
1997-02-01
Mass transfer through the solid boundary of a turbulent channel flow is analyzed by means of large-eddy simulation (LES) for Schmidt numbers Sc=1, 100, and 200. For that purpose the subgrid stresses and fluxes are closed using the Dynamic Mixed Model proposed by Zang et al. [Phys. Fluids A 5, 3186 (1993)]. At each Schmidt number the mass transfer coefficient given by the LES is found to be in very good quantitative agreement with that measured in the experiments. At high Schmidt number this coefficient behaves like Sc-2/3, as predicted by standard theory and observed in most experiments. The main statistical characteristics of the fluctuating concentration field are analyzed in connection with the well-documented statistics of the turbulent motions. It is observed that concentration fluctuations have a significant intensity throughout the channel at Sc=1 while they are negligible out of the wall region at Sc=200. The maximum intensity of these fluctuations depends on both the Schmidt and Reynolds numbers and is especially influenced by the intensity of the velocity fluctuations present in the buffer layer of the concentration field. At Sc=1, strong similarities are observed between the various terms contributing to the turbulent kinetic energy budget and their counterpart in the budget of the variance of concentration fluctuations. At high Schmidt number, the latter budget is much more influenced by the small turbulent structures subsisting in the viscous sublayer. The instantaneous correlation between the spatial characteristics of the concentration field and those of the velocity field is clearly demonstrated by the presence of low- and high-concentration streaks close to the wall. The geometrical characteristics of these structures are found to be highly Sc dependent. In particular their spanwise wavelength is identical to that of the streamwise velocity streaks at Sc=1 while it is reduced by half at Sc=200. Analysis of the co-spectra between concentration and
Particles, Feynman Diagrams and All That
Daniel, Michael
2006-01-01
Quantum fields are introduced in order to give students an accurate qualitative understanding of the origin of Feynman diagrams as representations of particle interactions. Elementary diagrams are combined to produce diagrams representing the main features of the Standard Model.
Boeker, Peter; Leppert, Jan; Mysliwietz, Bodo; Lammers, Peter Schulze
2013-10-01
The Deans' switch is an effluent switching device based on controlling flows of carrier gas instead of mechanical valves in the analytical flow path. This technique offers high inertness and a wear-free operation. Recently new monolithic microfluidic devices have become available. In these devices the whole flow system is integrated into a small metal device with low thermal mass and leak-tight connections. In contrast to a mechanical valve-based system, a flow-controlled system is more difficult to calculate. Usually the Deans' switch is used to switch one inlet to one of two outlets, by means of two auxiliary flows. However, the Deans' switch can also be used to deliver the GC effluent with a specific split ratio to both outlets. The calculation of the split ratio of the inlet flow to the two outlets is challenging because of the asymmetries of the flow resistances. This is especially the case, if one of the outlets is a vacuum device, such as a mass spectrometer, and the other an atmospheric detector, e.g. a flame ionization detector (FID) or an olfactory (sniffing) port. The capillary flows in gas chromatography are calculated with the Hagen-Poiseuille equation of the laminar, isothermal and compressible flow in circular tubes. The flow resistances in the new microfluidic devices have to be calculated with the corresponding equation for rectangular cross-section microchannels. The Hagen-Poiseuille equation underestimates the flow to a vacuum outlet. A corrected equation originating from the theory of rarefied flows is presented. The calculation of pressures and flows of a Deans' switch based chromatographic system is done by the solution of mass balances. A specific challenge is the consideration of the antidiffusion resistor between the two auxiliary gas lines of the Deans' switch. A full solution for the calculation of the Deans' switch including this restrictor is presented. Results from validation measurements are in good accordance with the developed
Causal diagrams for physical models
Kinsler, Paul
2015-01-01
I present a scheme of drawing causal diagrams based on physically motivated mathematical models expressed in terms of temporal differential equations. They provide a means of better understanding the processes and causal relationships contained within such systems.
Bayesian Networks and Influence Diagrams
DEFF Research Database (Denmark)
Kjærulff, Uffe Bro; Madsen, Anders Læsø
Probabilistic networks, also known as Bayesian networks and influence diagrams, have become one of the most promising technologies in the area of applied artificial intelligence, offering intuitive, efficient, and reliable methods for diagnosis, prediction, decision making, classification......, troubleshooting, and data mining under uncertainty. Bayesian Networks and Influence Diagrams: A Guide to Construction and Analysis provides a comprehensive guide for practitioners who wish to understand, construct, and analyze intelligent systems for decision support based on probabilistic networks. Intended...
Wind Diagrams in Medieval Iceland
DEFF Research Database (Denmark)
Kedwards, Dale
2014-01-01
This article presents a study of the sole wind diagram that survives from medieval Iceland, preserved in the encyclopaedic miscellany in Copenhagen's Arnamagnæan Institute with the shelf mark AM 732b 4to (c. 1300-25). It examines the wind diagram and its accompanying text, an excerpt on the winds...... from Isidore of Seville's Etymologies. It also examines the perimeter of winds on two medieval Icelandic world maps, and the visual traditions from which they draw....
Sun, Shuwen; Slaney, Thomas R; Kennedy, Robert T
2012-07-03
Droplet-based microfluidics is an attractive platform for screening and optimizing chemical reactions. Using this approach, it is possible to reliably manipulate nanoliter volume samples and perform operations such as reagent addition with high precision, automation, and throughput. Most studies using droplet microfluidics have relied on optical techniques to detect the reaction; however, this requires engineering color or fluorescence change into the reaction being studied. In this work, we couple electrospray ionization mass spectrometry (ESI-MS) to nanoliter scale segmented flow reactions to enable direct (label-free) analysis of reaction products. The system is applied to a screen of inhibitors for cathepsin B. In this approach, solutions of test compounds (including three known inhibitors) are arranged as an array of nanoliter droplets in a tube segmented by perfluorodecalin. The samples are pumped through a series of tees to add enzyme, substrate (peptides), and quenchant. The resulting reaction mixtures are then infused into a metal-coated, fused silica ESI emitter for MS analysis. The system has potential for high-throughput as reagent addition steps are performed at 0.7 s per sample and ESI-MS at up to 1.2 s per sample. Carryover is inconsequential in the ESI emitter and between 2 and 9% per reagent addition depending on the tee utilized. The assay was reliable with a Z-factor of ~0.8. The method required 0.8 pmol of test compound, 1.6 pmol of substrate, and 5 fmol of enzyme per reaction. Segmented flow ESI-MS allows direct, label free screening of reactions at good throughput and ultralow sample consumption.
MACROPORE FLOW AND MASS WASTING OF GULLIES IN THE LOESS PLATEAU, CHINA
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
Due to the extensive gullying from historically excessive erosion in the loess plateau of China, much of this region is being converted to native grass and shrub vegetation. Tunnel scour and mass wasting are important gully erosion processes resulting from preferential flow through macropores ( pores > 1 mm diameter). The objective of this study is to assess the changes with time in macropore flow characteristics of soils on the Loess Plateau following conversion to grass vegetation and the associated degree of mass wasting of gully faces. Ridge areas that had been revegetated for 1 year, 6 years, and > 15 years following tilling, and for 6 years following contour-ditching and the adjacent gully faces were characterized for their macropore and soil matrix properties on a 50 cm by 50 cm area. The total number of macropores increased from 11.6/m2 to 39.6/m2 from 1 to 6 years and to 51.6/m2 after 15 years of revegetation following tillage. The macroporosity increased from 0.0008 m3/m3 to 0.0018 m3/m3 from 1 to 6 years of revegetation following tillage but the lowest macroporosity (0.0005 m3/m3) was 6 years of revegetation following contour-ditching. The contour-ditched area had the lowest infiltration rate (95 m/d) through the soil matrix (areas without macropores) with the tilled areas having similar infiltration rates regardless of the number of years of revegetation (averaged 146 m/d). Due to tunnel scour erosion of macropores during infiltration into the area revegetated for 1 year, pore diameters enlarged by more than 200% resulting in this condition having the highest individual macropore infiltration rates (7967 m/d). Macropores in all other areas were stable with no tunnel scour erosion of macropores. The total capacity for infiltration through macropores increased significantly with time following revegetation. The number of macropores on the gully faces was triple (92.8/m2) and the macroporosity quadruple (0.004 m3/m3) that of the ridge surfaces. The upper
Energy Technology Data Exchange (ETDEWEB)
Llorca, Marta; Perez, Francisca [Department of Environmental Chemistry, IDAEA-CSIC, Barcelona (Spain); Farre, Marinella, E-mail: mfuqam@cid.csic.es [Department of Environmental Chemistry, IDAEA-CSIC, Barcelona (Spain); Agramunt, Silvia [Centre for Research in Environmental Epidemiology (CREAL), Barcelona (Spain); IMIM (Hospital del Mar Research Institute), Barcelona (Spain); Kogevinas, Manolis [Centre for Research in Environmental Epidemiology (CREAL), Barcelona (Spain); IMIM (Hospital del Mar Research Institute), Barcelona (Spain); CIBER Epidemiologia y Salud Publica (CIBERESP), Barcelona (Spain); National School of Public Health, Athens (Greece); Barcelo, Damia [Department of Environmental Chemistry, IDAEA-CSIC, Barcelona (Spain); Catalan Institute for Water Research (ICRA), Girona (Spain); King Saud University, Riyadh (Saudi Arabia)
2012-09-01
A fast on-line analytical method based on turbulent flow chromatography (TFC) in combination with tandem mass spectrometry has been applied for the first time for the analysis of eighteen perfluoroalkyl substances (PFASs), in cord blood. A simple and rapid sample pre-treatment was optimised consisting on protein precipitation of 100 {mu}L of sample with acetonitrile (1:1) followed by centrifugation during 10 min. The method was adapted to be sensitive enough and robust with minimum sample injection volume requirements (20 {mu}L). The optimised methodology presented method limits of detection (MLOD) between 0.031 and 0.76 {mu}g/L, detection capabilities (CC{alpha}) in the range between 0.005 and 0.99 {mu}g/L and decision limits (CC{beta}) ranging from 0.006 to 1.16 {mu}g/L. The recoveries in blank blood were calculated by spiking experiments with a mixture of 18 PFASs and established between 70 and 126% for most of compounds. Isotopic dilution was carried out for quantification of selected analytes. In-house validation of this new approach was carried out according to the requirements in the 2002/657/EC Decision. Finally the good applicability of this new approach was proved by the analysis of 60 cord blood samples from two different Mediterranean cities, Barcelona (Spain) and Heraklion (Greece). Ions perfluorohexanesulfonate (PFHxS) and perfluorooctanesulfonate (PFOS) were found at highest concentration and the more frequently compounds were PFHxS, PFOS and perfluorooctanoic acid (PFOA). The newly developed method proved to be suitable for large-scale epidemiologic studies, and to the data on PFASs exposure during pregnancy. -- Highlights: Black-Right-Pointing-Pointer An on-line method has been developed for the analysis of 18 perfluoroalkyl substances. Black-Right-Pointing-Pointer The method is based on turbulent flow chromatography tandem mass spectrometry. Black-Right-Pointing-Pointer The method was applied in 60 cord blood samples from 2 Mediterranean cities
Lau, S. S.; Liu, B. X.; Nicolet, M.-A.
1983-05-01
Interactions induced by ion irradiation are generally considered to be non-equilibrium processes, whereas phase diagrams are determined by phase equilibria. These two entities are seemingly unrelated. However, if one assumes that quasi-equilibrium conditions prevail after the prompt events, subsequent reactions are driven toward equilibrium by thermodynamical forces. Under this assumption, ion-induced reactions are related to equilibrium and therefore to phase diagrams. This relationship can be seen in the similarity that exists in thin films between reactions induced by ion irradiation and reactions induced by thermal annealing. In the latter case, phase diagrams have been used to predict the phase sequence of stable compound formation, notably so in cases of silicide formation. Ion-induced mixing not only can lead to stable compound formation, but also to metastable alloy formation. In some metal-metal systems, terminal solubilities can be greatly extended by ion mixing. In other cases, where the two constituents of the system have different crystal structures, extension of terminal solubility from both sides of the phase diagram eventually becomes structurally incompatible and a glassy (amorphous) mixture can form. The composition range where this bifurcation is likely to occur is in the two-phase regions of the phase diagram. These concepts are potentially useful guides in selecting metal pairs that from metallic glasses by ion mixing. In this report, phenomenological correlation between stable (and metastable) phase formation and phase diagram is discussed in terms of recent experimental data.
In silico approaches to study mass and energy flows in microbial consortia: a syntrophic case study
Directory of Open Access Journals (Sweden)
Mallette Natasha
2009-12-01
Full Text Available Abstract Background Three methods were developed for the application of stoichiometry-based network analysis approaches including elementary mode analysis to the study of mass and energy flows in microbial communities. Each has distinct advantages and disadvantages suitable for analyzing systems with different degrees of complexity and a priori knowledge. These approaches were tested and compared using data from the thermophilic, phototrophic mat communities from Octopus and Mushroom Springs in Yellowstone National Park (USA. The models were based on three distinct microbial guilds: oxygenic phototrophs, filamentous anoxygenic phototrophs, and sulfate-reducing bacteria. Two phases, day and night, were modeled to account for differences in the sources of mass and energy and the routes available for their exchange. Results The in silico models were used to explore fundamental questions in ecology including the prediction of and explanation for measured relative abundances of primary producers in the mat, theoretical tradeoffs between overall productivity and the generation of toxic by-products, and the relative robustness of various guild interactions. Conclusion The three modeling approaches represent a flexible toolbox for creating cellular metabolic networks to study microbial communities on scales ranging from cells to ecosystems. A comparison of the three methods highlights considerations for selecting the one most appropriate for a given microbial system. For instance, communities represented only by metagenomic data can be modeled using the pooled method which analyzes a community's total metabolic potential without attempting to partition enzymes to different organisms. Systems with extensive a priori information on microbial guilds can be represented using the compartmentalized technique, employing distinct control volumes to separate guild-appropriate enzymes and metabolites. If the complexity of a compartmentalized network creates an
Thandlam, Anil Kumar; Das, Chiranjib; Majumder, Subrata Kumar
2016-08-01
Investigation of wall-liquid mass transfer and heat transfer phenomena with gas-Newtonian and non-Newtonian fluids in vertically helical coil reactor have been reported in this article. Experiments were conducted to investigate the effect of various dynamic and geometric parameters on mass and heat transfer coefficients in the helical coil reactor. The flow pattern-based heat and mass transfer phenomena in the helical coil reactor are highlighted at different operating conditions. The study covered a wide range of geometric parameters such as diameter of the tube (d t ), diameter of the coil (D c ), diameter of the particle (d p ), pitch difference (p/D c ) and concentrations of non-Newtonian liquid. The correlation models for the heat and mass transfer coefficient based on the flow pattern are developed which may be useful in process scale-up of the helical coil reactor for industrial application. The frictional drag coefficient was also estimated and analyzed by mass transfer phenomena based on the electrochemical method.
Liang, Kang; Liu, Jingfu
2016-02-15
Although organophosphate esters (OPEs) in the ambient environment are from sewage treatment plants due to the discharge of effluent and application of sludge, the distribution, degradation and fate of OPEs in advanced municipal sewage treatment plants remain unclear. This work focused on the use of mass flow and mass balance analysis to understand the behaviors and fate of 14 OPEs in an advanced municipal sewage treatment plant. OPEs were detected in all sewage water and sludge samples with total OPEs (ΣOPEs) concentrations of 1399 ± 263 ng/L in raw sewage aqueous phase, 833 ± 175 ng/L in tertiary effluent aqueous phase, and 315 ± 89 ng/g dry weight in dewatered sludge. The dissolved concentrations of ΣOPEs significantly decreased during biological treatment, whereas negligible decrease was observed in mechanical and physical-chemical treatments. For individual OPE, the chlorinated tris(2-chloroethyl) phosphate (TCEP) and tris(2-chloroisopropyl) phosphate (TCPP) did not decrease but increased during both biological treatment and physical-chemical treatment. Mass flow analysis indicated the total removal efficiency of ΣOPEs in aqueous phase was 40.5%, and the polarity-specific removal efficiencies for individual OPE were positively related to their solid-water partition coefficients (Kd). Furthermore, mass balance results showed that 53.1% and 6.3% of the initial OPE mass flow were eventually transferred to the effluents and dewatered sludge, respectively, while the remaining 39.9% and 0.7% were lost due to biodegradation and physical-chemical treatment, respectively. It was indicated that the activated sludge treatment system with anaerobic/anoxic/aerobic bioreactors was a major factor in the removal of OPEs from the raw sewage, while transfer to dewatered sludge governed by hydrophobic interactions was limited during the sewage treatment. Meanwhile, the degradation difference of OPEs in activated sludge treatment was more related with their molecular
van de Ridder, Bert; Hakvoort, Wouter; van Dijk, Johannes
2015-01-01
In this paper we describe the design, implementation and results of multi degree of freedom (DOF) active vibration control for a Coriolis mass-flow meter (CMFM). Without vibration control, environmental vibrational disturbances results in nanometre movement of the fluid-conveying tube which causes
Mol, J.G.J.; Dam, van R.C.J.
2014-01-01
Flow injection combined with tandem mass spectrometry (MS/MS) was investigated for the rapid detection of highly polar pesticides that are not amenable to multi-residue methods because they do not partition into organic solvents and require dedicated chromatographic conditions. The pesticides includ
Brass, M.; Roeckmann, T.
2010-01-01
We describe a continuous-flow isotope ratio mass spectrometry (CF-IRMS) technique for high-precision δD and δ13C measurements of atmospheric methane on 40 mL air samples. CH4 is separated from other air components by utilizing purely physical processes based on temperature, time and mechanical valve
DEFF Research Database (Denmark)
Ratkovich, Nicolas Rios; Berube, P.R.; Nopens, I.
2011-01-01
) cannot be applied directly. As an alternative, in this work, a multidisciplinary approach was selected, by exploiting dimensionless analysis using the Sherwood number. Mass transfer coefficients were measured at various superficial velocities of gas and liquid flow in a tubular system. Due...
Wang, Fengyang; Wang, Shuxiao; Zhang, Lei; Yang, Hai; Gao, Wei; Wu, Qingru; Hao, Jiming
2016-05-01
The iron and steel production process is one of the predominant anthropogenic sources of atmospheric mercury emissions worldwide. In this study, field tests were conducted to study mercury emission characteristics and mass flows at two iron and steel plants in China. It was found that low-sulfur flue gas from sintering machines could contribute up to 41% of the total atmospheric mercury emissions, and desulfurization devices could remarkably help reduce the emissions. Coal gas burning accounted for 17%-49% of the total mercury emissions, and therefore the mercury control of coal gas burning, specifically for the power plant burning coal gas to generate electricity, was significantly important. The emissions from limestone and dolomite production and electric furnaces can contribute 29.3% and 4.2% of the total mercury emissions from iron and steel production. More attention should be paid to mercury emissions from these two processes. Blast furnace dust accounted for 27%-36% of the total mercury output for the whole iron and steel production process. The recycling of blast furnace dust could greatly increase the atmospheric mercury emissions and should not be conducted. The mercury emission factors for the coke oven, sintering machine and blast furnace were 0.039-0.047gHg/ton steel, and for the electric furnace it was 0.021gHg/ton steel. The predominant emission species was oxidized mercury, accounting for 59%-73% of total mercury emissions to air.
Flow of Burgers’ fluid over an inclined stretching sheet with heat and mass transfer
Institute of Scientific and Technical Information of China (English)
T Hayat; Sadia Asad; A Alsaedi
2015-01-01
Effects of heat and mass transfer in the flow of Burgers fluid over an inclined sheet are discussed. Problems formulation and relevant analysis are given in the presence of thermal radiation and non-uniform heat source/sink. Thermal conductivity is taken temperature dependent. The nonlinear partial differential equations are simplified using boundary layer approximations. The resultant nonlinear ordinary differential equations are solved for the series solutions. The convergence of series solutions is obtained by plotting theh-curves for the velocity, temperature and concentration fields. Results of this work describe the role of different physical parameters involved in the problem. The Deborah numbers corresponding to relaxation time (β1andβ2) and angle of inclination (α) decrease the fluid velocity and concentration field. Concentration field decays as Deborah numbers corresponding to retardation time (β3) and mixed convection parameter (G) increase. Large values of heat generation/absorption parametersA/B, and the temperature distribution across the boundary layer increase. Numerical values of local Nusselt number,−θ′(0), and local Sherwood number,−f′(0), are computed and analyzed. It is found thatθ′(0) increases with an increase inβ3.
Directory of Open Access Journals (Sweden)
Shodiya Sulaimon
2014-07-01
Full Text Available The capillary tube is an important control device used in small vapor compression refrigeration systems such as window air-conditioners, household refrigerators and freezers. This paper develops a non-dimensional correlation based on the test results of the adiabatic capillary tube for the mass flow rate through the tube using a hydrocarbon refrigerant mixture of 89.3% propane and 10.7% butane (HCM. The Taguchi method, a statistical experimental design approach, was employed. This approach explores the economic benefit that lies in studies of this nature, where only a small number of experiments are required and yet valid results are obtained. Considering the effects of the capillary tube geometry and the inlet condition of the tube, dimensionless parameters were chosen. The new correlation was also based on the Buckingham Pi theorem. This correlation predicts 86.67% of the present experimental data within a relative deviation of -10% to +10%. The predictions by this correlation were also compared with results in published literature.
Fine Magnetic Structure and Origin of Counter-Streaming Mass Flows in a Quiescent Solar Prominence
Shen, Yuandeng; Liu, Ying D; Chen, P F; Su, Jiangtao; Xu, Zhi; Liu, Zhong
2015-01-01
We present high-resolution observations of a quiescent solar prominence which was consisted of a vertical and a horizontal foot encircled by an overlying spine, and counter-streaming mass flows were ubiquitous in the prominence. While the horizontal foot and the spine were connecting to the solar surface, the vertical foot was suspended above the solar surface and supported by a semicircular bubble structure. The bubble first collapsed and then reformed at a similar height, finally, it started to oscillate for a long time. We find that the collapsing and oscillation of the bubble boundary were tightly associated with a flare-like feature located at the bottom of the bubble. Based on the observational results, we propose that the prominence should be composed of an overlying horizontal spine encircling a low-lying horizontal and a vertical foot, in which the horizontal foot was consisted of shorter field lines running partially along the spine and with the both ends connecting to the solar surface, while the v...
On the features, successes and challenges of selected ion flow tube mass spectrometry.
Spanel, Patrik; Smith, David
2013-01-01
The major features of the selected ion flow tube mass spectrometry (SIFT-MS) analytical method that was conceived and designed for the analysis, in real time, of air obviating sample collections into bags or extraction by pre-concentration of trace compounds onto surfaces are reviewed. The unique analytical capabilities of SIFT-MS for ambient analysis are stressed that allow quantification of volatile organic and inorganic compounds directly from the measurement of physical parameters without the need for regular instrumental calibration using internal or external standards. Then, emphasis is placed on the challenging real-time accurate analysis of single exhalations of humid breath, which is now achieved and readily facilitates wider applications of SIFT-MS in other fields where trace gas analysis has value. The quality of the data obtained by SIFT-MS is illustrated by the quantification of some exhaled breath metabolites that are of immediate relevance to physiology and medicine, including that of hydrogen cyanide in the breath of patients with cystic fibrosis. The current status of SIFT-MS is revealed by a form of a strengths, weakness, opportunities and threats (SWOT) analysis intended to present an objective view of this analytical technique and the likely way forward towards its further development and application.
Three-Dimensional Electro-Sonic Flow Focusing Ionization Microfluidic Chip for Mass Spectrometry
Directory of Open Access Journals (Sweden)
Cilong Yu
2015-12-01
Full Text Available Increasing research efforts have been recently devoted to the coupling of microfluidic chip-integrated ionization sources to mass spectrometry (MS. Considering the limitations of microfluidic chips coupled with MS such as liquid spreading, dead volume, and manufacturing troubles, this paper proposed a new three-dimensional (3D flow focusing (FF-based microfluidic ionizing source. This source was fabricated by using the two-layer soft lithography method with the nozzle placed inside the chip. The proposed FF microfluidic chip can realize two-phase FF with liquid in air regardless of the viscosity ratio of the continuous and dispersed phases. MS results indicated that the proposed FF microfluidic chip can work as a typical electrical ionization source when supplied with high voltage and can serve as a sonic ionization source without high voltage. The electro-sonic FF ionization microfluidic chip is expected to have various applications, particularly in the integrated and portable applications of ionization sources coupling with portable MS in the future.
Inoue, Hiroyuki; Hashimoto, Hiroaki; Watanabe, Susumu; Iwata, Yuko T; Kanamori, Tatsuyuki; Miyaguchi, Hajime; Tsujikawa, Kenji; Kuwayama, Kenji; Tachi, Noriyuki; Uetake, Naohito
2009-09-01
A novel approach to the analysis of ecstasy tablets by direct mass spectrometry coupled with thermal desorption (TD) and counter-flow introduction atmospheric pressure chemical ionization (CFI-APCI) is described. Analytes were thermally desorbed with a metal block heater and introduced to a CFI-APCI source with ambient air by a diaphragm pump. Water in the air was sufficient to act as the reactive reagent responsible for the generation of ions in the positive corona discharge. TD-CFI-APCI required neither a nebulizing gas nor solvent flow and the accompanying laborious optimizations. Ions generated were sent in the direction opposite to the air flow by an electric field and introduced into an ion trap mass spectrometer. The major ions corresponding to the protonated molecules ([M + H](+)) were observed with several fragment ions in full scan mass spectrometry (MS) mode. Collision-induced dissociation of protonated molecules gave characteristic product-ion mass spectra and provided identification of the analytes within 5 s. The method required neither sample pretreatment nor a chromatographic separation step. The effectiveness of the combination of TD and CFI-APCI was demonstrated by application to the direct mass spectrometric analysis of ecstasy tablets and legal pharmaceutical products.
Energy Technology Data Exchange (ETDEWEB)
Boukadida, N. [Faculte des Sciences, Dept. of Physics, Monastir (Tunisia); Ben Nasrallah, S. [Ecole Nationale d' Ingenieurs de Monastir, Dept. of Energetics (Tunisia)
2001-01-01
A detailed numerical analysis concerning the mechanism of heat and mass transfer during water evaporation in a two dimensional steady laminar flow of dry air or air-vapor mixture in a horizontal channel is studied. The gas is considered as absorbing, emitting and non-scattering medium with variable thermophysical properties. The results show the effect of different state variables on the coefficients of heat and mass transfer and the domain where the analogy between the heat and mass transfer is valid. They also show the effect of the thermal radiation on the ratio between Sherwood and Nusselt numbers. The comparison between the present results and those obtained in previous published studies [32-34] features to a satisfactory agreement. (authors)
Qureshi, M. Zubair Akbar; Ali, Kashif; Iqbal, M. Farooq; Ashraf, Muhammad; Ahmad, Shazad
2017-01-01
The numerical study of heat and mass transfer for an incompressible magnetohydrodynamics (MHD) nanofluid flow containing spherical shaped nanoparticles through a channel with moving porous walls is presented. Further, another endeavour is to study the effect of two types of fluids, namely the metallic nanofluid (Au + water) and metallic-oxides nanofluid (TiO2 + water) are studied. The phenomena of spherical metallic and metallic-oxides nanoparticles have been also mathematically modelled by using the Hamilton-Crosser model. The influence of the governing parameters on the flow, heat and mass transfer aspects of the problem is discussed. The outcome of the investigation may be beneficial to the application of biotechnology and industrial purposes. Numerical solutions for the velocity, heat and mass transfer rate at the boundary are obtained and analysed.
Zhao, X.
1992-01-01
We show that the 25 November 1978 shock pair was caused by the interaction of a fast steady flow with a slow coronal mass ejection in interplanetary space (ICME). It is suggested that the slow ICME may be disconnected from the sun. In addition, a new method to infer the shock angle and Mach number from the observed upstream plasma beta and the jump ratios of proton density and magnetic flux density across a shock is described.
Directory of Open Access Journals (Sweden)
M. Das
2015-12-01
Full Text Available The influence of Newtonian heating on heat and mass transfer in unsteady hydromagnetic flow of a Casson fluid past a vertical plate in the presence of thermal radiation and chemical reaction is studied. The Casson fluid model is used to distinguish the non-Newtonian fluid behavior. The fluid flow is induced due to periodic oscillations of the plate along its length and a uniform transverse magnetic field is applied in a direction which is normal to the direction of fluid flow. The partial differential equations governing the flow, heat, and mass transfer are transformed to non-dimensional form using suitable non-dimensional variables which are then solved analytically by using Laplace transform technique. The numerical values of the fluid velocity, fluid temperature, and species concentration are depicted graphically whereas the values of skin-friction, Nusselt number, and Sherwood number are presented in tabular form. It is noticed that the fluid velocity and temperature decrease with increasing values of Casson parameter while concentration decreases with increasing values of chemical reaction parameter and Schmidt number. Such a fluid flow model has several industrial and medical applications such as in glass manufacturing, paper production, purification of crude oil and study of blood flow in the cardiovascular system.
Material flow of production process
Hanzelová Marcela
2001-01-01
This paper deals with material flow of the production process. We present the block diagram of material flow and capacities of engine in various plants each other. In this paper is used IPO (Input Process Output) diagram. IPO diagram described process with aspect to input and output. Production program regards string of precision, branch and paralel processes with aspect IPO diagram.Process is not important with aspect to events. We are looking on the process as a black box. For process is ...
Perfect orderings on Bratteli diagrams
Bezuglyi, Sergey; Yassawi, Reem
2012-01-01
Given a Bratteli diagram B, we study the set O(B) of all possible orderings w on a Bratteli diagram B and its subset P(B) consisting of `perfect' orderings that produce Bratteli-Vershik dynamical systems (Vershik maps). We give necessary and sufficient conditions for w to be perfect. On the other hand, a wide class of non-simple Bratteli diagrams that do not admit Vershik maps is explicitly described. In the case of finite rank Bratteli diagrams, we show that the existence of perfect orderings with a prescribed number of extreme paths affects significantly the values of the entries of the incidence matrices and the structure of the diagram B. Endowing the set O(B) with product measure, we prove that there is some j such that almost all orderings on B have j maximal and minimal paths, and that if j is strictly greater than the number of minimal components that B has, then almost all orderings are imperfect.
Peuke, A.D.; Windt, C.W.; As, van H.
2006-01-01
The effects of cold girdling of the transport phloem at the hypocotyl of Ricinus communis on solute and water transport were investigated. Effects on the chemical composition of saps of phloem and xylem as well as of stem tissue were studied by conventional techniques and the water flow in the phloe
Peuke, A.D.; Windt, C.W.; As, van H.
2006-01-01
The effects of cold girdling of the transport phloem at the hypocotyl of Ricinus communis on solute and water transport were investigated. Effects on the chemical composition of saps of phloem and xylem as well as of stem tissue were studied by conventional techniques and the water flow in the
Scherr, Rachel E.; Harrer, Benedikt W.; Close, Hunter G.; Daane, Abigail R.; DeWater, Lezlie S.; Robertson, Amy D.; Seeley, Lane; Vokos, Stamatis
2016-02-01
Energy is a crosscutting concept in science and features prominently in national science education documents. In the Next Generation Science Standards, the primary conceptual learning goal is for learners to conserve energy as they track the transfers and transformations of energy within, into, or out of the system of interest in complex physical processes. As part of tracking energy transfers among objects, learners should (i) distinguish energy from matter, including recognizing that energy flow does not uniformly align with the movement of matter, and should (ii) identify specific mechanisms by which energy is transferred among objects, such as mechanical work and thermal conduction. As part of tracking energy transformations within objects, learners should (iii) associate specific forms with specific models and indicators (e.g., kinetic energy with speed and/or coordinated motion of molecules, thermal energy with random molecular motion and/or temperature) and (iv) identify specific mechanisms by which energy is converted from one form to another, such as incandescence and metabolism. Eventually, we may hope for learners to be able to optimize systems to maximize some energy transfers and transformations and minimize others, subject to constraints based in both imputed mechanism (e.g., objects must have motion energy in order for gravitational energy to change) and the second law of thermodynamics (e.g., heating is irreversible). We hypothesize that a subsequent goal of energy learning—innovating to meet socially relevant needs—depends crucially on the extent to which these goals have been met.
Improving modeling with layered UML diagrams
DEFF Research Database (Denmark)
Störrle, Harald
2013-01-01
Layered diagrams are diagrams whose elements are organized into sets of layers. Layered diagrams are routinely used in many branches of engineering, except Software Engineering. In this paper, we propose to add layered diagrams to UML modeling tools, and elaborate the concept by exploring usage...
Directory of Open Access Journals (Sweden)
Jyotsna Rani Pattnaik
2017-03-01
Full Text Available An analysis of unsteady MHD free convection flow, heat and mass transfer past an exponentially accelerated inclined plate embedded in a saturated porous medium with uniform permeability, variable temperature and concentration has been carried out. The novelty of the present study was to analyze the effect of angle of inclination on the flow phenomena in the presence of heat source/sink and destructive reaction. The Laplace transformation method has been used to solve the governing equations. The effects of the material parameters, magnetic field and the permeability of the porous medium are discussed. From the present analysis it is reported that the presence of magnetic field and porous medium prevents the flow reversal. Angle of inclination and heat source sustains a retarding effect on velocity. The present study has an immediate application in understanding the drag experienced at the heated/cooled and inclined surfaces in a seepage flow.
Water flow in fractured rock masses: numerical modeling for tunnel inflow assessment
Gattinoni, P.; Scesi, L.; Terrana, S.
2009-04-01
Water circulation in rocks represents a very important element to solve many problems linked with civil, environmental and mining engineering. In particular, the interaction of tunnelling with groundwater has become a very relevant problem not only due to the need to safeguard water resources from impoverishment and from the pollution risk, but also to guarantee the safety of workers and to assure the efficiency of the tunnel drainage systems. The evaluation of the hydrogeological risk linked to the underground excavation is very complex, either for the large number of variables involved or for the lack of data available during the planning stage. The study is aimed to quantify the influence of some geo-structural parameters (i.e. discontinuities dip and dip direction) on the tunnel drainage process, comparing the traditional analytical method to the modeling approach, with specific reference to the case of anisotropic rock masses. To forecast the tunnel inflows, a few Authors suggest analytic formulations (Goodman et al., 1965; Knutsson et al., 1996; Ribacchi et al., 2002; Park et al., 2008; Perrochet et al., 2007; Cesano et al., 2003; Hwang et al., 2007), valid for infinite, homogeneous and isotropic aquifer, in which the permeability value is given as a modulus of equivalent hydraulic conductivity Keq. On the contrary, in discontinuous rock masses the water flow is strongly controlled by joints orientation, by their hydraulic characteristics and by rocks fracturing conditions. The analytic equations found in the technical literature could be very useful, but often they don't reflect the real phenomena of the tunnel inflow in rock masses. Actually, these equations are based on the hypothesis of homogeneous aquifer, and then they don't give good agreement for an heterogeneous fractured medium. In this latter case, the numerical modelling could provide the best results, but only with a detailed conceptual model of the water circulation, high costs and long
Nonabelian cut diagrams and their applications
Lam, C S
1996-01-01
A new kind of cut diagram is introduced to sum Feynman diagrams with nonabelian vertices. Unlike the Cutkosky diagrams which compute the discontinuity of single Feynman diagrams, the nonabelian cut diagrams represent a resummation of both the real and the imaginary parts of Feynman diagrams related by permutations. Several applications of the technique are reported, including a resolution of the apparent inconsistency of the baryon problem in large-N_c QCD, a simplified calculation of high-energy low-order QCD diagrams, and progress made with this technique on the unitarization of the BFKL equation.
The spectroscopic Hertzsprung-Russell diagram of Galactic massive stars
Castro, N; Langer, N; Simón-Díaz, S; Schneider, F R N; Izzard, R G
2014-01-01
The distribution of stars in the Hertzsprung-Russell diagram narrates their evolutionary history and directly assesses their properties. Placing stars in this diagram however requires the knowledge of their distances and interstellar extinctions, which are often poorly known for Galactic stars. The spectroscopic Hertzsprung-Russell diagram (sHRD) tells similar evolutionary tales, but is independent of distance and extinction measurements. Based on spectroscopically derived effective temperatures and gravities of almost 600 stars, we derive for the first time the observational distribution of Galactic massive stars in the sHRD. While biases and statistical limitations in the data prevent detailed quantitative conclusions at this time, we see several clear qualitative trends. By comparing the observational sHRD with different state-of-the-art stellar evolutionary predictions, we conclude that convective core overshooting may be mass-dependent and, at high mass ($\\geq 15\\,M_\\odot$), stronger than previously thou...
Visualizing spacetimes via embedding diagrams
Hledik, Stanislav; Cipko, Alois
2016-01-01
It is hard to imagine curved spacetimes of General Relativity. A simple but powerful way how to achieve this is visualizing them via embedding diagrams of both ordinary geometry and optical reference geometry. They facilitate to gain an intuitive insight into the gravitational field rendered into a curved spacetime, and to assess the influence of parameters like electric charge and spin of a black hole, magnetic field or cosmological constant. Optical reference geometry and related inertial forces and their relationship to embedding diagrams are particularly useful for investigation of test particles motion. Embedding diagrams of static and spherically symmetric, or stationary and axially symmetric black-hole and naked-singularity spacetimes thus present a useful concept for intuitive understanding of these spacetimes' nature. We concentrate on general way of embedding into 3-dimensional Euclidean space, and give a set of illustrative examples.
Walitt, L.
1982-01-01
The VANS successive approximation numerical method was extended to the computation of three dimensional, viscous, transonic flows in turbomachines. A cross-sectional computer code, which conserves mass flux at each point of the cross-sectional surface of computation was developed. In the VANS numerical method, the cross-sectional computation follows a blade-to-blade calculation. Numerical calculations were made for an axial annular turbine cascade and a transonic, centrifugal impeller with splitter vanes. The subsonic turbine cascade computation was generated in blade-to-blade surface to evaluate the accuracy of the blade-to-blade mode of marching. Calculated blade pressures at the hub, mid, and tip radii of the cascade agreed with corresponding measurements. The transonic impeller computation was conducted to test the newly developed locally mass flux conservative cross-sectional computer code. Both blade-to-blade and cross sectional modes of calculation were implemented for this problem. A triplet point shock structure was computed in the inducer region of the impeller. In addition, time-averaged shroud static pressures generally agreed with measured shroud pressures. It is concluded that the blade-to-blade computation produces a useful engineering flow field in regions of subsonic relative flow; and cross-sectional computation, with a locally mass flux conservative continuity equation, is required to compute the shock waves in regions of supersonic relative flow.
Tecklenburg, Jan; Neuweiler, Insa; Carrera, Jesus; Dentz, Marco
2016-05-01
We study modeling of two-phase flow in highly heterogeneous fractured and porous media. The flow behaviour is strongly influenced by mass transfer between a highly permeable (mobile) fracture domain and less permeable (immobile) matrix blocks. We quantify the effective two-phase flow behavior using a multirate rate mass transfer (MRMT) approach. We discuss the range of applicability of the MRMT approach in terms of the pertinent viscous and capillary diffusion time scales. We scrutinize the linearization of capillary diffusion in the immobile regions, which allows for the formulation of MRMT in the form of a non-local single equation model. The global memory function, which encodes mass transfer between the mobile and the immobile regions, is at the center of this method. We propose two methods to estimate the global memory function for a fracture network with given fracture and matrix geometry. Both employ a scaling approach based on the known local memory function for a given immobile region. With the first method, the local memory function is calculated numerically, while the second one employs a parametric memory function in form of truncated power-law. The developed concepts are applied and tested for fracture networks of different complexity. We find that both physically based parameter estimation methods for the global memory function provide predictive MRMT approaches for the description of multiphase flow in highly heterogeneous porous media.
Dryahina, Kseniya; Smith, D; Spanel, P
2010-05-15
In selected ion flow tube mass spectrometry, SIFT-MS, analyses of humid air and breath, it is essential to consider and account for the influence of water vapour in the media, which can be profound for the analysis of some compounds, including H(2)CO, H(2)S and notably CO(2). To date, the analysis of methane has not been considered, since it is known to be unreactive with H(3)O(+) and NO(+), the most important precursor ions for SIFT-MS analyses, and it reacts only slowly with the other available precursor ion, O(2) (+). However, we have now experimentally investigated methane analysis and report that it can be quantified in both air and exhaled breath by exploiting the slow O(2) (+)/CH(4) reaction that produces CH(3)O(2) (+) ions. We show that the ion chemistry is significantly influenced by the presence of water vapour in the sample, which must be quantified if accurate analyses are to be performed. Thus, we have carried out a study of the loss rate of the CH(3)O(2) (+) analytical ion as a function of sample humidity and deduced an appropriate kinetics library entry that provides an accurate analysis of methane in air and breath by SIFT-MS. However, the associated limit of detection is rather high, at 0.2 parts-per-million, ppm. We then measured the methane levels, together with acetone levels, in the exhaled breath of 75 volunteers, all within a period of 3 h, which shows the remarkable sample throughput rate possible with SIFT-MS. The mean methane level in ambient air is seen to be 2 ppm with little spread and that in exhaled breath is 6 ppm, ranging from near-ambient levels to 30 ppm, with no significant variation with age and gender. Methane can now be included in the wide ranging analyses of exhaled breath that are currently being carried out using SIFT-MS.
Iverson, Richard M.; Chaojun Ouyang,
2015-01-01
Earth-surface mass flows such as debris flows, rock avalanches, and dam-break floods can grow greatly in size and destructive potential by entraining bed material they encounter. Increasing use of depth-integrated mass- and momentum-conservation equations to model these erosive flows motivates a review of the underlying theory. Our review indicates that many existing models apply depth-integrated conservation principles incorrectly, leading to spurious inferences about the role of mass and momentum exchanges at flow-bed boundaries. Model discrepancies can be rectified by analyzing conservation of mass and momentum in a two-layer system consisting of a moving upper layer and static lower layer. Our analysis shows that erosion or deposition rates at the interface between layers must in general satisfy three jump conditions. These conditions impose constraints on valid erosion formulas, and they help determine the correct forms of depth-integrated conservation equations. Two of the three jump conditions are closely analogous to Rankine-Hugoniot conditions that describe the behavior of shocks in compressible gasses, and the third jump condition describes shear traction discontinuities that necessarily exist across eroding boundaries. Grain-fluid mixtures commonly behave as compressible materials as they undergo entrainment, because changes in bulk density occur as the mixtures mobilize and merge with an overriding flow. If no bulk density change occurs, then only the shear-traction jump condition applies. Even for this special case, however, accurate formulation of depth-integrated momentum equations requires a clear distinction between boundary shear tractions that exist in the presence or absence of bed erosion.
Energy Technology Data Exchange (ETDEWEB)
Espinosa-Paredes, Gilberto, E-mail: gepe@xanum.uam.m [Area de Ingenieria en Recursos Energeticos, Universidad Autonoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco, 186, Col. Vicentina, Mexico D.F., 09340 (Mexico); Verma, Surendra P. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Priv. Xochicalco s/no., Col Centro, Apartado Postal 34, Temixco 62580 (Mexico); Vazquez-Rodriguez, Alejandro [Area de Ingenieria en Recursos Energeticos, Universidad Autonoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco, 186, Col. Vicentina, Mexico D.F., 09340 (Mexico); Nunez-Carrera, Alejandro [Comision Nacional de Seguridad Nuclear y Salvaguardias, Doctor Barragan 779, Col. Narvarte, Mexico D.F. 03020 (Mexico)
2010-05-15
Our aim was to evaluate the sensitivity and uncertainty of mass flow rate in the core on the performance of natural circulation boiling water reactor (NCBWR). This analysis was carried out through Monte Carlo simulations of sizes up to 40,000, and the size, i.e., repetition of 25,000 was considered as valid for routine applications. A simplified boiling water reactor (SBWR) was used as an application example of Monte Carlo method. The numerical code to simulate the SBWR performance considers a one-dimensional thermo-hydraulics model along with non-equilibrium thermodynamics and non-homogeneous flow approximation, one-dimensional fuel rod heat transfer. The neutron processes were simulated with a point reactor kinetics model with six groups of delayed neutrons. The sensitivity was evaluated in terms of 99% confidence intervals of the mean to understand the range of mean values that may represent the entire statistical population of performance variables. The regression analysis with mass flow rate as the predictor variable showed statistically valid linear correlations for both neutron flux and fuel temperature and quadratic relationship for the void fraction. No statistically valid correlation was observed for the total heat flux as a function of the mass flow rate although heat flux at individual nodes was positively correlated with this variable. These correlations are useful for the study, analysis and design of any NCBWR. The uncertainties were propagated as follows: for 10% change in the mass flow rate in the core, the responses for neutron power, total heat flux, average fuel temperature and average void fraction changed by 8.74%, 7.77%, 2.74% and 0.58%, respectively.
FLOW BEHAVIOR AND MASS TRANSFER IN THREE-PHASE EXTERNAL-LOOP AIRLIFT REACTORS WITH LARGE PARTICLES
Institute of Scientific and Technical Information of China (English)
Malin; Liu; Tongwang; Zhang; Tiefeng; Wang; Jinfu; Wang; Yong; Jin
2006-01-01
The flow behavior and mass transfer in a three-phase external-loop airlift reactor can be improved by adding large particles. The mass transfer and liquid dispersion behavior for a three-phase external-loop reactor with large particles are studied in terms of the effect of the diameter and loading of the large particles on the liquid dispersion coefficient and mass transfer coefficient. The results showed that increasing the diameter or loading of the large particles tend to decrease dispersion and intensify mass transfer, and that an increase in the diameter of the large particles remarkably decreases the particle loop rate, while the effect of fine particles is much less notable.
COMPUTER SIMULATION OF NON-NEWTONIAN FLOW AND MASS TRANSPORT THROUGH CORONARY ARTERIAL STENOSIS
Institute of Scientific and Technical Information of China (English)
李新宇; 温功碧; 李丁
2001-01-01
A numerical analysis of Newtonian and non-Newtonian flow in an axi-symmetric tube with a local constriction simulating a stenosed artery under steady and pulsatile flow conditions was carried out. Based on these results, the concentration fields of LDL ( low density lipoprotein ) and Albumin were discussed. According to the results, in great details the macromolecule transport influences of wall shear stress, non-Newtonian fluid character and the scale of the molecule etc are given. The results of Newtonian fluid flow and non Newtonian fluid flow , steady flow and pulsatile flow are compared. These investigations can provide much valuable information about the correlation between the flow properties, the macromolecule transport and the development of atherosclerosis.
DEFF Research Database (Denmark)
Schmidt, Bjørn; Löschner, Katrin; Hadrup, Niels
2011-01-01
An analytical platform coupling asymmetric flow field-flow fractionation (AF4) with multiangle light scattering (MALS), dynamic light scattering (DLS), and inductively coupled plasma mass spectrometry (ICPMS) was established and used for separation and quantitative determination of size and mass ...
Between Analogue and Digital Diagrams
Directory of Open Access Journals (Sweden)
Zoltan Bun
2012-10-01
Full Text Available This essay is about the interstitial. About how the diagram, as a method of design, has lead fromthe analogue deconstruction of the eighties to the digital processes of the turn of the millennium.Specifically, the main topic of the text is the interpretation and the critique of folding (as a diagramin the beginning of the nineties. It is necessary then to unfold its relationship with immediatelypreceding and following architectural trends, that is to say we have to look both backwards andforwards by about a decade. The question is the context of folding, the exchange of the analogueworld for the digital. To understand the process it is easier to investigate from the fields of artand culture, rather than from the intentionally perplicated1 thoughts of Gilles Deleuze. Both fieldsare relevant here because they can similarly be used as the yardstick against which the era itselfit measured. The cultural scene of the eighties and nineties, including performing arts, movies,literature and philosophy, is a wide milieu of architecture. Architecture responds parallel to itsera; it reacts to it, and changes with it and within it. Architecture is a medium, it has always beena medium, yet the relations are transformed. That’s not to say that technical progress, for exampleusing CAD-software and CNC-s, has led to the digital thinking of certain movements ofarchitecture, (it is at most an indirect tool. But the ‘up-to-dateness’ of the discipline, however,a kind of non-servile reading of an ‘applied culture’ or ‘used philosophy’2 could be the key.(We might recall here, parenthetically, the fortunes of the artistic in contemporary mass society.The proliferation of museums, the magnification of the figure of the artist, the existence of amassive consumption of printed and televised artistic images, the widespread appetite for informationabout the arts, all reflect, of course, an increasingly leisured society, but also relateprecisely to the fact
HEAT AND MASS TRANSFER FOR VISCO-ELASTIC MHD BOUNDARY LAYER FLOW PAST A VERTICAL FLAT PLATE
Directory of Open Access Journals (Sweden)
Rita Choudhury
2012-07-01
Full Text Available The two-dimensional free convection flow of visco-elastic and electrically conducting fluid past a vertical impermeable flat plate is considered in presence of a uniform transverse magnetic field. The governing equations are reduced to ordinary differential equation by introducing appropriate co-ordinate transformation. The analytical expressions for the velocity, temperature and species concentration fields have been obtained. The corresponding expressions for the non-dimensional rates of heat transfer and mass transfer have beenobtained. The velocity profile and the shearing stress have been illustrated graphically, for various values of flow parameters involved in the solution to observe the effect of visco-elastic parameter.
Directory of Open Access Journals (Sweden)
Jagdish PRAKASH
2014-01-01
Full Text Available This paper studies flow, heat, and mass transfer characteristics of unsteady mixed convective magnetohydrodynamic (MHD flow of a heat absorbing fluid in an accelerated vertical wavy plate, subject to varying temperature and mass diffusion, with the influence of buoyancy, thermal radiation and Dufour effect. The momentum, energy and mass diffusion equations are coupled non-linear partial differential equations, which are solved by perturbation technique. The features of the fluid flow, heat and mass transfer characteristics are analyzed by plotting graphs, and the physical aspects are discussed in detail to interpret the effects of significant parameters of the problem.doi:10.14456/WJST.2014.69
Directory of Open Access Journals (Sweden)
Chandrakala P.
2014-05-01
Full Text Available A numerical technique is employed to derive a solution to the transient natural convection flow of an incompressible viscous fluid past an impulsively started infinite isothermal vertical plate with uniform mass diffusion in the presence of a magnetic field and homogeneous chemical reaction of first order. The governing equations are solved using implicit finite-difference method. The effects of velocity, temperature and concentration for different parameters such as the magnetic field parameter, chemical reaction parameter, Prandtl number, Schmidt number, thermal Grashof number and mass Grashof number are studied. It is observed that the fluid velocity decreases with increasing the chemical reaction parameter and the magnetic field parameter.
Sheridan, M. F.; Stinton, A. J.; Patra, A.; Pitman, E. B.; Bauer, A.; Nichita, C. C.
2005-01-01
The Titan2D geophysical mass-flow model is evaluated by comparing its simulation results and those obtained from another flow model, FLOW3D, with published data on the 1963 Little Tahoma Peak avalanches on Mount Rainier, Washington. The avalanches, totaling approximately 10×10 6 m 3 of broken lava blocks and other debris, traveled 6.8 km horizontally and fell 1.8 km vertically ( H/ L=0.246). Velocities calculated from runup range from 24 to 42 m/s and may have been as high as 130 m/s while the avalanches passed over Emmons Glacier. Titan2D is a code for an incompressible Coulomb continuum; it is a depth-averaged, 'shallow-water', granular-flow model. The conservation equations for mass and momentum are solved with a Coulomb-type friction term at the basal interface. The governing equations are solved on multiple processors using a parallel, adaptive mesh, Godunov scheme. Adaptive gridding dynamically concentrates computing power in regions of special interest; mesh refinement and coarsening key on the perimeter of the moving avalanche. The model flow initiates as a pile defined as an ellipsoid by a height ( z) and an elliptical base defined by radii in the x and y planes. Flow parameters are the internal friction angle and bed friction angle. Results from the model are similar in terms of velocity history, lateral spreading, location of runup areas, and final distribution of the Little Tahoma Peak deposit. The avalanches passed over the Emmons Glacier along their upper flow paths, but lower in the valley they traversed stream gravels and glacial outwash deposits. This presents difficulty in assigning an appropriate bed friction angle for the entire deposit. Incorporation of variable bed friction angles into the model using GIS will help to resolve this issue.
Mclean, J. D.; Randall, J. L.
1979-01-01
A system of computer programs for calculating three dimensional transonic flow over wings, including details of the three dimensional viscous boundary layer flow, was developed. The flow is calculated in two overlapping regions: an outer potential flow region, and a boundary layer region in which the first order, three dimensional boundary layer equations are numerically solved. A consistent matching of the two solutions is achieved iteratively, thus taking into account viscous-inviscid interaction. For the inviscid outer flow calculations, the Jameson-Caughey transonic wing program FLO 27 is used, and the boundary layer calculations are performed by a finite difference boundary layer prediction program. Interface programs provide communication between the two basic flow analysis programs. Computed results are presented for the NASA F8 research wing, both with and without distributed surface suction.
Heat and mass transfer in two-phase flow motion in minichannel under variable heating
Directory of Open Access Journals (Sweden)
Chachilo Evgenii S.
2014-01-01
Full Text Available Experimental studying the effect of temperature on evaporation dynamics of the stationary horizontal liquid layer is presented. The average evaporation flow rate of liquid layer (ethanol by the gas flow (air has been calculated using two independent methods. The dependence of the evaporation flow rate from the temperature has been obtained. According to the analysis of the results it was found that the dependence is nonlinear and described by an exponential function.
Bayesian Networks and Influence Diagrams
DEFF Research Database (Denmark)
Kjærulff, Uffe Bro; Madsen, Anders Læsø
Bayesian Networks and Influence Diagrams: A Guide to Construction and Analysis, Second Edition, provides a comprehensive guide for practitioners who wish to understand, construct, and analyze intelligent systems for decision support based on probabilistic networks. This new edition contains six new...
Electrical elementary diagrams and operators
Energy Technology Data Exchange (ETDEWEB)
Patterson, B.K. [Human Factors Practical Inc., Dipper Harbour, New Brunswick (Canada)]. E-mail: HumanFactors@netscape.ca
2005-07-01
After 40 years of reading and interrupting electrical elementary logic drawings, I have concluded that we need to make a change. We need to write and express our nuclear power plant logic in some other language than relay ladder logic, solid state logic or computer mnemonics. The language should be English, or your native language, and the format should be Descriptive Block Diagrams. (author)
The diagram for phyllotactic series
Directory of Open Access Journals (Sweden)
Joanna Szymanowska-Pułka
2014-01-01
Full Text Available Many authors studying phyllotaxis in various plant species have reported the occurrence of many different numbers of contact parastichy pairs that are members of different Fibonacci-like series. On the basis of these reports a diagram was constructed in which any theoretically possible series was represented by the two first members of a given series.
BIHOURLY DIAGRAMS OF FORBUSH DECREASES
Bihourly diagrams were made of Forbush decreases of cosmic ray intensity as observed at Uppsala from 31 Aug 56 to 31 Dec 59, at Kiruna from Nov 56 to 31 Dec 59, and at Murchison Bay from 26 Aug 57 to 30 Apr 59. (Author)
Phase diagram of Hertzian spheres
Pàmies, J.C.; Cacciuto, A.; Frenkel, D.
2009-01-01
We report the phase diagram of interpenetrating Hertzian spheres. The Hertz potential is purely repulsive, bounded at zero separation, and decreases monotonically as a power law with exponent 5/2, vanishing at the overlapping threshold. This simple functional describes the elastic interaction of wea
Bayesian Networks and Influence Diagrams
DEFF Research Database (Denmark)
Kjærulff, Uffe Bro; Madsen, Anders Læsø
Bayesian Networks and Influence Diagrams: A Guide to Construction and Analysis, Second Edition, provides a comprehensive guide for practitioners who wish to understand, construct, and analyze intelligent systems for decision support based on probabilistic networks. This new edition contains six new...
Multi-currency Influence Diagrams
DEFF Research Database (Denmark)
Nielsen, Søren Holbech; Nielsen, Thomas Dyhre; Jensen, Finn V.
2007-01-01
When using the influence diagrams framework for solving a decision problem with several different quantitative utilities, the traditional approach has been to convert the utilities into one common currency. This conversion is carried out using a tacit transformation, under the assumption that the...
Multi-currency Influence Diagrams
DEFF Research Database (Denmark)
Nielsen, Søren Holbech; Nielsen, Thomas Dyhre; Jensen, Finn Verner
2004-01-01
that the converted problem is equivalent to the original one. In this paper we present an extension of the Influence Diagram framework, which allows for these decision problems to be modelled in their original form. We present an algorithm that, given a conversion function between the currencies, discovers...
Directory of Open Access Journals (Sweden)
Thao M. Nguyen
2015-07-01
Full Text Available Gold nanorods (GNRs are of particular interest for biomedical applications due to their unique size-dependent longitudinal surface plasmon resonance band in the visible to near-infrared. Purified GNRs are essential for the advancement of technologies based on these materials. Used in concert, asymmetric-flow field flow fractionation (A4F and single particle inductively coupled mass spectrometry (spICP-MS provide unique advantages for fractionating and analyzing the typically complex mixtures produced by common synthetic procedures. A4F fractions collected at specific elution times were analyzed off-line by spICP-MS. The individual particle masses were obtained by conversion of the ICP-MS pulse intensity for each detected particle event, using a defined calibration procedure. Size distributions were then derived by transforming particle mass to length assuming a fixed diameter. The resulting particle lengths correlated closely with ex situ transmission electron microscopy. In contrast to our previously reported observations on the fractionation of low-aspect ratio (AR GNRs (AR < 4, under optimal A4F separation conditions the results for high-AR GNRs of fixed diameter (≈20 nm suggest normal, rather than steric, mode elution (i.e., shorter rods with lower AR generally elute first. The relatively narrow populations in late eluting fractions suggest the method can be used to collect and analyze specific length fractions; it is feasible that A4F could be appropriately modified for industrial scale purification of GNRs.
Influence of heat and mass flux conditions in hydromagnetic flow of Jeffrey nanofluid
Energy Technology Data Exchange (ETDEWEB)
Abbasi, F. M. [Department of Mathematics, Comsats Institute of Information Technology, Islamabad 44000 (Pakistan); Shehzad, S. A., E-mail: ali-qau70@yahoo.com [Department of Mathematics, Comsats Institute of Information Technology, Sahiwal 57000 (Pakistan); Hayat, T. [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); Alsaedi, A.; Obid, Mustafa A. [Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia)
2015-03-15
This article explores the hydromagnetic steady flow of Jeffrey fluid in the presence of thermal radiation. The chosen nanofluid model takes into account the Brownian motion and thermophoresis effects. Flow and heat transfer characteristics are determined by a stretching surface with flux conditions. The nonlinear boundary layer flow through partial differential systems is converted into the ordinary differential systems. The resulting reduced systems are computed for the convergent solutions of velocity, temperature and nanoparticle concentration. Graphs of dimensionless temperature and nanoparticle concentration profiles are presented for different values of emerging parameters. Skin-friction coefficient are computed and analyzed in both hydrodynamic and hydromagnetic flow situations.
Influence of heat and mass flux conditions in hydromagnetic flow of Jeffrey nanofluid
Directory of Open Access Journals (Sweden)
F. M. Abbasi
2015-03-01
Full Text Available This article explores the hydromagnetic steady flow of Jeffrey fluid in the presence of thermal radiation. The chosen nanofluid model takes into account the Brownian motion and thermophoresis effects. Flow and heat transfer characteristics are determined by a stretching surface with flux conditions. The nonlinear boundary layer flow through partial differential systems is converted into the ordinary differential systems. The resulting reduced systems are computed for the convergent solutions of velocity, temperature and nanoparticle concentration. Graphs of dimensionless temperature and nanoparticle concentration profiles are presented for different values of emerging parameters. Skin-friction coefficient are computed and analyzed in both hydrodynamic and hydromagnetic flow situations.
Energy Technology Data Exchange (ETDEWEB)
Dismon, Heinrich; Grimm, Karsten; Toennesmann, Andres; Nigrin, Sven [Pierburg GmbH, Neuss (Germany); Wienand, Karlheinz; Muziol, Matthias [Heraeus Sensor Technology GmbH, Kleinostheim (Germany)
2008-07-01
Due to increasingly stringent emission standards, a number of internal measures as well as exhaust gas aftertreatment systems have become state-of-the-art technology for passenger car and heavy duty engines. However, the full potential of these measures, for example the cooled external exhaust gas recirculation, can only be utilized if the engine control is adapted adequately well in all engine states. Thus, the requirements for future engine controls become more demanding and consequently the standards for sensors used in the control loop will increase. In this context this article introduces a new exhaust gas mass flow sensor based or the principle of hot film anemometry. The sensor comprising a ceramic sensor element is developed especially for the use in engine exhaust gases providing the exhaust gas mass flow as a direct measurement and control variable. Next to the sensor technology first results of engine tests are presented in this paper. (orig.)
Chua, K. J.; Xu, J.; Cui, X.; Ng, K. C.; Islam, M. R.
2016-09-01
In this study the performance of an indirect evaporative cooling system (IECS) of cross-flow configuration is numerically investigated. Considering the variation of water film temperature along the flowing path and the wettability of the wet channel, a two-dimensional theoretical model is developed to comprehensively describe the heat and mass transfer process involved in the system. After comparing the simulation results with available experimental data from literature, the deviation within ±5 % proves the accuracy and reliability of the proposed mathematical model. The simulation results of the plate type IECS indicate that the important parameters, such as dimension of plates, air properties, and surface wettability play a great effect on the cooling performance. The investigation of flow pattern shows that cross-flow configuration of primary air with counter-flow of secondary air and water film has a better cooling performance than that of the parallel-flow pattern. Furthermore, the performance of a novel flat tube working as the separating medium is numerically investigated. Simulation results for this novel geometry indicate that the tube number, tube long axis and short axis length as well as tube length remarkably affect its cooling performance.
Storer, Malina K; Hibbard-Melles, Kim; Davis, Brett; Scotter, Jenny
2011-10-01
Selected ion flow tube-mass spectrometry has been used to measure the volatile compounds occurring in the headspace of urine samples inoculated with common urinary tract infection (UTI)-causing microbes Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella pneumoniae, Enterococcus faecalis, or Candida albicans. This technique has the potential to offer rapid and simple diagnosis of the causative agent of UTIs.
Energy Technology Data Exchange (ETDEWEB)
Homing Yeh; Chiidong Ho [Tamkang Univ. Tamsui, Dept. of Chemical Engineering, Taipei Hsien (Taiwan)
2000-04-01
Considerable improvement in productivity may be obtained if water vapor in the last-effect unit is carried away directly by flowing air. The theory of a closed-type upward multiple-effect solar distiller has been modified to that of an open-type device, and the energy and mass balances have been derived. The production rate of distilled water for each effect under various climate, design, and operational conditions may be predicted by simultaneously solving the appropriate equations. (Author)
Tecklenburg, Jan; Carrera, Jesus; Dentz, Marco
2016-01-01
We study modeling of two-phase flow in highly heterogeneous fractured and porous media. The flow behaviour is strongly influenced by mass transfer between a highly permeable (mobile) fracture domain and less permeable (immobile) matrix blocks. We quantify the effective two-phase flow behaviour using a multirate rate mass transfer (MRMT) approach. We discuss the range of applicability of the MRMT approach in terms of the pertinent viscous and capillary diffusion time scales. We scrutinize the linearization of capillary diffusion in the immobile regions, which allows for the formulation of MRMT in the form of a non-local single equation model. The global memory function, which encodes mass transfer between the mobile and the immobile regions, is at the center of this method. We propose two methods to estimate the global memory function for a fracture network with given fracture and matrix geometry. Both employ a scaling approach based on the known local memory function for a given immobile region. With the firs...
Heat or mass transfer at low Péclet number for Brinkman and Darcy flow round a sphere
Bell, Christopher G.
2014-01-01
Prior research into the effect of convection on steady-state mass transfer from a spherical particle embedded in a porous medium has used the Darcy model to describe the flow. However, a limitation of the Darcy model is that it does not account for viscous effects near boundaries. Brinkman modified the Darcy model to include these effects by introducing an extra viscous term. Here we investigate the impact of this extra viscous term on the steady-state mass transfer from a sphere at low Péclet number, Pe 1. We use singular perturbation techniques to find the approximate asymptotic solution for the concentration profile. Mass-release from the surface of the sphere is described by a Robin boundary condition, which represents a first-order chemical reaction. We find that a larger Brinkman viscous boundary layer renders mass transport by convection less effective, and reduces the asymmetry in the peri-sphere concentration profiles. We provide simple analytical expressions that can be used to calculate the concentration profiles, as well as the local and average Sherwood numbers; and comparison to numerical simulations verifies the order of magnitude of the error in the asymptotic expansions. In the appropriate limits, the asymptotic results agree with solutions previously obtained for Stokes and Darcy flow. The solution for Darcy flow with a Robin boundary condition has not been considered previously in the literature and is a new result. Whilst the article has been formulated in terms of mass transfer, the analysis is also applicable to heat transfer, with concentration replaced by temperature and the Sherwood number by the Nusselt number. © 2013 Elsevier Ltd. All rights reserved.
Institute of Scientific and Technical Information of China (English)
张燕来; 朱慧铭; 尹秋响
2011-01-01
A chromochemical reactive mass transfer technique has been employed to study local mass transfer characteristics of structured packing. This technology adopted by experiment is an Ammonia Adsorption Method （AAM） that yields the surface distribution of transferred mass by analyzing the color distribution on a filter paper with the results of the color chemical reaction. A digital image processing technology is applied for data visualiza-tion. The three-dimensional plot of the local mass transfer coefficients shows that there exist three peak values on different positions of a unit cell of structured packing. In order to improve mass transfer efficiency of the structured packing, one piece of baffle is added between packing sheets. As a result, the average mass transfer coefficient increases by （10 20）% and the pressure drop decreases by （15-55）%.
Institute of Scientific and Technical Information of China (English)
Ben Abdelghani Farouk; Aubertin Michel; Simon Richard; Therrien René
2015-01-01
A numerical tool, called Hydro-Geosphere, was used to simulate unsaturated water flow and contami-nants migration around an open pit filled with mining wastes. Numerical simulations had been carried out to assess the influence of various factors on water flow and solute transport in and around the surface openings including recharge, properties of the waste material and presence of fractures in the surround-ing rock mass. The effect of the regional hydraulic gradient was also investigated. The analyses were con-ducted by simulating various 2D cases using experimentally obtained material properties and controlled boundary conditions. The effects of the hydrogeological properties of the filling material (i.e., water reten-tion curve and hydraulic conductivity function), fracture network characteristics and conductivity of the joints were assessed. The results illustrate that fractures control water flow and contaminants transport around the waste disposal area. A fracture network can desaturate the system and improve the regional gradient effect.
Directory of Open Access Journals (Sweden)
G.S. Seth
2014-06-01
Full Text Available An investigation of the effects of Hall current and rotation on unsteady hydromagnetic natural convection flow with heat and mass transfer of an electrically conducting, viscous, incompressible and optically thick radiating fluid past an impulsively moving vertical plate embedded in a fluid saturated porous medium, when temperature of the plate has a temporarily ramped profile, is carried out. Exact solution of the governing equations is obtained in closed form by Laplace transform technique. Exact solution is also obtained in case of unit Schmidt number. Expressions for skin friction due to primary and secondary flows and Nusselt number are derived for both ramped temperature and isothermal plates. Expression for Sherwood number is also derived. The numerical values of primary and secondary fluid velocities, fluid temperature and species concentration are displayed graphically whereas those of skin friction are presented in tabular form for various values of pertinent flow parameters.
Perez-Rea, Daysi; Zielke, Claudia; Nilsson, Lars
2017-07-14
Starch and hence, amylopectin is an important biomacromolecule in both the human diet as well as in technical applications. Therefore, accurate and reliable analytical methods for its characterization are needed. A suitable method for analyzing macromolecules with ultra-high molar mass, branched structure and high polydispersity is asymmetric flow field-flow fractionation (AF4) in combination with multiangle light scattering (MALS) detection. In this paper we illustrate how co-elution of low quantities of very large analytes in AF4 may cause disturbances in the MALS data which, in turn, causes an overestimation of the size. Furthermore, it is shown how pre-injection filtering of the sample can improve the results. Copyright © 2017 Elsevier B.V. All rights reserved.
Lactic Acid Extraction and Mass Transfer Characteristics in Slug Flow Capillary Microreactors
Susanti,; Winkelman, Jozef G.M.; Schuur, Boelo; Heeres, Hero J.; Yue, Jun
2016-01-01
Capillary microreactors operated under the slug flow regime were investigated for the separation of lactic acid from the aqueous phase using liquid–liquid reactive extraction. The experiments were performed at a 1:1 flow ratio of the aqueous to organic phases in a setup consisting of an inlet Y-type
Modelling of cross-flow membrane contactors : Physical mass transfer processes
Dindore, V. Y.; Brilman, D. W. F.; Versteeg, G. F.
2005-01-01
Traditionally, hollow fiber membrane contactors used for gas-liquid contacting were designed in a shell and tube configuration with shell-side fluid flowing parallel to the fiber-side fluid, either in co-current or counter-current pattern. The primary limitations of these so-called 'parallel flow' c
Directory of Open Access Journals (Sweden)
Farooqi Ahmad Salam
2017-01-01
Full Text Available Bubble flow reactors (BFR are commonly used for various industrial processes in the field of oil and gas production, pharmaceutical industries, biochemical and environmental engineering etc. The operation and performance of these reactors rely heavily on a range of hydrodynamic parameters; prominent among them are geometric configurations including gas injection geometry, operating conditions, mass transfer etc. A huge body of literature is available to describe the optimum design and performance of bubbly flow reactors with conventional bubble injection. Attempts were made to modify gas injection for improved efficiency of BFR’s. However, here instead of modifying the geometry of the gas injection, an attempt has been made to generate swirl bubbles for gaining larger mass transfer between gas and liquid. Here an exceptionally well thought strategies have been used in our numerical simulations towards the design of swirl injection mechanism, whose paramount aspect is to inhibit the rotary liquid motion but facilitates the swirl movement for bubbles in nearly stationary liquid. Our comprehension here is that the swirl motion can strongly affect the performance of bubbly reactor by identifying the changes in hydrodynamic parameters as compared to the conventional bubbly flows. In order to achieve this bubbly flow, an experimental setup has been designed as well as computational fluid dynamic (CFD code was used with to highlight a provision of swirl bubble injection by rotating the sparger plate.
Kinematical Diagrams for Conical Relativistic Jets
Indian Academy of Sciences (India)
Gopal-Krishna; Pronoy Sircar; Samir Dhurde
2007-03-01
We present diagrams depicting the expected inter-dependences of two key kinematical parameters of radio knots in the parsec-scale jets of blazars, deduced from VLBI observations. The two parameters are the apparent speed (app = capp) and the effective Doppler boosting factor (eff) of the relativistically moving radio knot. A novel aspect of these analytical computations of – diagrams is that they are made for parsecscale jets having a conical shape, with modest opening angles ( up to 10°), in accord with the VLBI observations of the nuclei of the nearest radio galaxies. Another motivating factor is the recent finding that consideration of a conical geometry can have important implications for the interpretation of a variety of radio observations of blazar jets. In addition to uniform jet flows (i.e., those having a uniform bulk Lorentz factor, ), computational results are also presented for stratified jets where an ultra-relativistic central spine along the jet axis is surrounded by a slower moving sheath, possibly arising from a velocity shear.
Klepiszewski, Kai; Venditti, Silvia; Koehler, Christian
2016-07-01
The development of a strategic approach to manage pollution of surface waters with pharmaceutical residues is in centre of interest in Europe. In this context a lack of reliable standard procedures for sampling and subsequent assessment of pharmaceutical mass flows in the water cycle has been identified. Authoritative assessment of relevant substance concentrations and flows is essential for environmental risk assessments and reliable efficiency analysis of measures to reduce or avoid emissions of drugs to water systems. Accordingly, a detailed preparation of monitoring campaigns including an accuracy check for the sampling configuration provides important information on the reliability of the gathered data. It finally supports data analysis and interpretation for evaluations of the efficiency of measures as well as for cost benefit assessments. The precision of mass flow balances is expected to be particularly weak when substances with high short-term variations and rare upstream emissions are considered. This is especially true for substance flow analysis in sewers close to source because of expectable highly dynamic flow conditions and emission patterns of pollutants. The case study presented here focusses on the verification of a monitoring campaign in a hospital sewer in Luxembourg. The results highlight the importance for a priori accuracy checks and provide a blueprint for well-designed monitoring campaigns of pharmaceutical trace pollutants on the one hand. On the other hand, the study provides evidence that the defined and applied continuous flow proportional sampling procedure enables a representative monitoring of short-term peak loads of the x-ray contrast media iobitridol close to source. Copyright © 2016. Published by Elsevier Ltd.
Sequential maneuvering decisions based on multi-stage influence diagram in air combat
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
A multi-stage influence diagram is used to model the pilot's sequential decision making in one on one air combat.The model based on the multi-stage influence diagram graphically describes the elements of decision process,and contains a point-mass model for the dynamics of an aircraft and takes into account the decision maker's Dreferences under uncertain conditions.Considering an active opponent,the opponent's maneuvers can be modeled stochastically.The solution of multistage influence diagram Can be obtained by converting the multistage influence diagram into a two-level optimization problem.The simulation results show the model is effective.
Non-radial solar wind flows induced by the motion of interplanetary coronal mass ejections
Directory of Open Access Journals (Sweden)
M. Owens
2004-12-01
Full Text Available A survey of the non-radial flows (NRFs during nearly five years of interplanetary observations revealed the average non-radial speed of the solar wind flows to be ~30km/s, with approximately one-half of the large (>100km/s NRFs associated with ICMEs. Conversely, the average non-radial flow speed upstream of all ICMEs is ~100km/s, with just over one-third preceded by large NRFs. These upstream flow deflections are analysed in the context of the large-scale structure of the driving ICME. We chose 5 magnetic clouds with relatively uncomplicated upstream flow deflections. Using variance analysis it was possible to infer the local axis orientation, and to qualitatively estimate the point of interception of the spacecraft with the ICME. For all 5 events the observed upstream flows were in agreement with the point of interception predicted by variance analysis. Thus we conclude that the upstream flow deflections in these events are in accord with the current concept of the large-scale structure of an ICME: a curved axial loop connected to the Sun, bounded by a curved (though not necessarily circular cross section.
Key words. Interplanetary physics (flare and stream dynamics; interplanetary magnetic fields; interplanetary shocks
Continuum modelling of the collapse of a granular mass and its subsequent flow
Lagrée, P.; Staron, L.; Popinet, S.
2011-12-01
The continuum modelling of transient granular flows is of primary importance in the context of prediction and risk mitigation in relation with rock avalanches and dry debris flows. In this perspective, the granular column collapse experiment provides an interesting benchmark, due to both its relevance to natural granular flows and its challenging complexity (Lube 2004 et al, Lajeunesse et al 2006). In this contribution, we present 2D continuum simulations of granular column collapse using the Navier-Stokes solver Gerris (Popinet 2003), solving the full Navier-Stokes equations. The rheology implemented to model the granular media is the so-called μ (I) rheology, relating the frictional properties and the viscosity of the material to the pressure and shear rate (Jop et al 2006). In addition, discrete simulations using the Contact Dynamics method are performed for systematic comparison between the granular flow dynamics and its continuum counterpart (Staron & Hinch 2005). We find a good agreement, recovering the shape of the flow in the course of time, the internal flow structure, as well as experimental scaling laws for the run-out. A systematic underestimation of the latter is nevertheless observed, and discussed in terms of physical and numerical modeling. This work opens important new prospect for the simulation of more complex situations relevant to geophysical granular flows.
Llopis-Albert, Carlos; Capilla, José E.
2009-06-01
SummaryIn the first paper of this series a methodology for the generation of non-Gaussian transmissivity fields conditional to flow, mass transport and secondary data was presented. This methodology, referred to as the gradual conditioning (GC) method, constitutes a new and advanced powerful approach in the field of stochastic inverse modelling. It is based on gradually changing an initial transmissivity ( T) field, conditioned only to T and secondary data, to honour flow and transport measured data. The process is based on combining the initial T field with other seed T fields in successive iterations maintaining the stochastic structure of T, previously inferred from data. The iterative procedure involves the minimization of a penalty function which depends on one parameter, and is made up by the weighted summation of the square deviations among flow and/or transport variables, and the corresponding known measurements. The GC method leads gradually to a final simulated field, uniformly converging to a better reproduction of conditioning data as more iterations are performed. The methodology is now demonstrated on a synthetic aquifer in a non-multi-Gaussian stochastic framework. First, an initial T field is simulated, and retained as reference T field. With prescribed head boundary conditions, transient flow created by an abstraction well and a mass solute plume migrating through the formation, a long-term and large scale hypothetical tracer experiment is run in this reference synthetic aquifer. Then T, piezometric head ( h), solute concentration ( c) and travel time ( τ) are sampled at a limited number of points, and for different time steps where applicable. Using this limited amount of information the GC method is applied, conditioning to different sets of these sampled data and model results are compared to those from the reference synthetic aquifer. Results demonstrate the ability and robustness of the GC method to include different types of data without
Unravelling the multiphase run-out conditions of a slide- flow mass movement
van Asch, Theo; Xu, Qiang; Dong, X.J.
2014-01-01
In this paper an attempt is made to unravel the run-out characteristics of a mass movement in the Sichuan Province, SW China by means of 1D numerical modelling and calibration on the topography of run-out profiles.The Dagou mass movement started as a rockslide with an initial volume of 480,000m3, wh
Revised state diagram of Laponite dispersions.
Mongondry, Philippe; Tassin, Jean François; Nicolai, Taco
2005-03-15
We propose a state diagram of charged disk-like mineral particle (Laponite) dispersions as a function of the Laponite concentration (C) and the concentration of added salt (C(s)), based on simple observation and light-scattering measurements. At low C or high C(s) the dispersions separate into two domains due to sedimentation of Laponite aggregates, while at high C and low C(s) they form homogeneous gels that do not flow upon tube reversal. The aggregation rate and the structure factor of the Laponite dispersions is determined with light scattering as a function of C and C(s). We discuss in detail the controversy on the origin of gelation of Laponite dispersions in the absence of added salt. We argue that aggregation rather than glass formation causes gelation.
Directory of Open Access Journals (Sweden)
Timoshevskiy Mikhail V.
2016-01-01
Full Text Available We studied cavitating flow over the suction side of a symmetric 2D foil – a scaled-down model of high-pressure hydroturbine guide vanes (GV – in different cavitation regimes at the attack angle of 3°. High-speed imaging was used to analyze spatial patterns and time dynamics of the gas-vapour cavities. A hydroacoustic pressure transducer was employed to register time-spectra of pressure fluctuations nearby the hydrofoil. A PIV technique was applied to measure the velocity fields and its fluctuations. The active flow control was implemented by means of a continuous liquid supply with different flow rates through a slot channel located in the GV surface. It was found that the active mass injection does not influence the primary flow upstream of the slot channel position. For the cavitation-free and cavitation inception cases, the injection was shown to make the turbulent wake past the GV section more intense. However, at the developed cavitation regimes the active flow management made it possible to reduce substantially the amplitude or even totally suppress the periodic cavity length oscillations and pressure pulsations associated with them.
Mass flow and reaction analysis of the growth of GaN by HVPE
Kempisty, P.; Grzegory, I.; Bokowski, M.; Krukowski, S.; Ucznik, B.; Pastuszka, B.; Porowski, S.
2006-01-01
HVPE growth in horizontal flow reactor has been analysed using finite element calculations and molecular estimates of the reaction rates. Finite element code FIDAP (commercially available from Fluent Inc.) has been used to calculate the flow pattern in the reactor. In the first approximation it was assumed that the flow pattern is weekly dependent on the temperature distribution in the reactor. It was also assumed that the volume reaction rates can be approximated by temperature independent reaction constants. The HCl + Ga(l) reaction rate has been estimated using ideal gas approximation for HCl vapour.The degree of HCl to GaCl conversion was obtained in function of the pressure, flow velocity and geometry of the reactor. The conversion dependence on the sticking coefficient of HCl on liquid Ga surface was analysed. It is shown that for the typical design of the reactor, high conversion rates were observed, even for the sticking coefficient as low as 0.001.
Energy Technology Data Exchange (ETDEWEB)
Uckan, T.
2005-11-11
The implementation plans and preparations for installation of the Fissile Mass Flow Monitor (FMFM) equipment at the ElectroChemical Plant (ECP), Zelenogorsk, Russia, are presented in this report. The FMFM, developed at Oak Ridge National Laboratory, is part of the Blend Down Monitoring System (BDMS), developed for the U.S. Department of Energy Highly Enriched Uranium (HEU) Transparency Implementation Program. The BDMS provides confidence to the United States that the Russian nuclear facilities supplying the lower-assay ({approx}4%) product low enriched uranium (P-LEU) to the United States from down-blended weapons-grade HEU are meeting the nonproliferation goals of the government-to-government HEU Purchase Agreement, signed between the Russian Federation and the United States in 1993. The first BDMS has been operational at Ural Electrochemical Integrated Plant, Novouralsk, since February 1999 and is successfully providing HEU transparency data to the United States. The second BDMS was installed at ECP in February 2003. The FMFM makes use of a set of thermalized californium-252 ({sup 252}Cf) spontaneous neutron sources for a modulated fission activation of the UF{sub 6} gas stream for measuring the {sup 235}U fissile mass flow rate. To do this, the FMFM measures the transport time of the fission fragments created from the fission activation process under the modulated source to the downstream detectors by detecting the delayed gamma rays from the fission fragments. The FMFM provides unattended, nonintrusive measurements of the {sup 235}U mass flow in the HEU, LEU blend stock, and P-LEU process legs. The FMFM also provides the traceability of the HEU flow to the product process leg. This report documents the technical installation requirements and the expected operational characteristics of the ECP FMFM.
Directory of Open Access Journals (Sweden)
Rosenfeld Moshe
2010-05-01
Full Text Available Abstract Background Published studies of the past decades have established that mass transfer across the dialyzer membrane is governed by diffusion, convection and osmosis. While the former is independent of the pressure in the liquids, the latter two are pressure dependent and are enhanced when the pressure difference across the membrane is increased. The goal of the present study is to examine the impact of pulsatile flow on the transport phenomena across the membrane of a high-flux dialyzer in a wearable artificial kidney (WAK with a novel single small battery-operated pulsatile pump that drives both the blood and dialysate in a counter-phased manner, maximizing the trans-membrane pressure. Methods Both in-vitro experimental and numerical tools are employed to compare the performance of the pulsatile WAK dialyzer with a traditional design of a single-channel roller blood pump together with a centrifugal pump that drives the dialysate flow. The numerical methods utilize the axisymmetric Navier-Stokes and mass transfer equations to model the flow in the fibers of the dialyzer. Results While diffusion is still the dominating transport regime, the WAK pump enhances substantially the trans-membrane pressure and thus increases mass convection that might be as high as 30% of the overall transfer. This increase is obtained due to the design of the pulsatile WAK pump that increases ultrafiltration by increasing the trans-membrane pressure. Conclusions The experimental and numerical results revealed that when pumping at similar flow rates, a small battery-operated pulsatile pump provides clearances of urea and creatinine similar as or better than a large heavy AC-powered roller pump.
Hero's journey in bifurcation diagram
Monteiro, L. H. A.; Mustaro, P. N.
2012-06-01
The hero's journey is a narrative structure identified by several authors in comparative studies on folklore and mythology. This storytelling template presents the stages of inner metamorphosis undergone by the protagonist after being called to an adventure. In a simplified version, this journey is divided into three acts separated by two crucial moments. Here we propose a discrete-time dynamical system for representing the protagonist's evolution. The suffering along the journey is taken as the control parameter of this system. The bifurcation diagram exhibits stationary, periodic and chaotic behaviors. In this diagram, there are transition from fixed point to chaos and transition from limit cycle to fixed point. We found that the values of the control parameter corresponding to these two transitions are in quantitative agreement with the two critical moments of the three-act hero's journey identified in 10 movies appearing in the list of the 200 worldwide highest-grossing films.
Anatomy of geodesic Witten diagrams
Chen, Heng-Yu; Kuo, En-Jui; Kyono, Hideki
2017-05-01
We revisit the so-called "Geodesic Witten Diagrams" (GWDs) [1], proposed to be the holographic dual configuration of scalar conformal partial waves, from the perspectives of CFT operator product expansions. To this end, we explicitly consider three point GWDs which are natural building blocks of all possible four point GWDs, discuss their gluing procedure through integration over spectral parameter, and this leads us to a direct identification with the integral representation of CFT conformal partial waves. As a main application of this general construction, we consider the holographic dual of the conformal partial waves for external primary operators with spins. Moreover, we consider the closely related "split representation" for the bulk to bulk spinning propagator, to demonstrate how ordinary scalar Witten diagram with arbitrary spin exchange, can be systematically decomposed into scalar GWDs. We also discuss how to generalize to spinning cases.
Compressible Flow Produced by Distributed Sources of Mass: An Exact Solution
Clarke, J.F.
1987-01-01
The paper considers the case of a one-dimensional isentropic unsteady compressible flow that is driven entirely by a distribution of sources in the left-hand half space of an unbounded domain. The right-hand half-space contains no sources, so that source-strength drops discontinuously to zero as one crosses from left to right-hand space. Exact solutions are obtained for those parts of the flow that remain isentropic.
Hubble's diagram and cosmic expansion
Kirshner, Robert P.
2003-01-01
Edwin Hubble's classic article on the expanding universe appeared in PNAS in 1929 [Hubble, E. P. (1929) Proc. Natl. Acad. Sci. USA 15, 168–173]. The chief result, that a galaxy's distance is proportional to its redshift, is so well known and so deeply embedded into the language of astronomy through the Hubble diagram, the Hubble constant, Hubble's Law, and the Hubble time, that the article itself is rarely referenced. Even though Hubble's distances have a large systematic error, Hubble's velo...
Hubble's diagram and cosmic expansion
Kirshner, Robert P.
2003-01-01
Edwin Hubble's classic article on the expanding universe appeared in PNAS in 1929 [Hubble, E. P. (1929) Proc. Natl. Acad. Sci. USA 15, 168–173]. The chief result, that a galaxy's distance is proportional to its redshift, is so well known and so deeply embedded into the language of astronomy through the Hubble diagram, the Hubble constant, Hubble's Law, and the Hubble time, that the article itself is rarely referenced. Even though Hubble's distances have a large systematic error, Hubble's velo...
Reliability computation from reliability block diagrams
Chelson, P. O.; Eckstein, E. Y.
1975-01-01
Computer program computes system reliability for very general class of reliability block diagrams. Four factors are considered in calculating probability of system success: active block redundancy, standby block redundancy, partial redundancy, and presence of equivalent blocks in the diagram.
Choi, Jaeyeong; Zielke, Claudia; Nilsson, Lars; Lee, Seungho
2017-07-01
The macromolecular composition of beer is largely determined by the brewing and the mashing process. It is known that the physico-chemical properties of proteinaceous and polysaccharide molecules are closely related to the mechanism of foam stability. Three types of "American pale ale" style beer were prepared using different mashing protocols. The foam stability of the beers was assessed using the Derek Rudin standard method. Asymmetric flow field-flow fractionation (AF4) in combination with ultraviolet (UV), multiangle light scattering (MALS) and differential refractive index (dRI) detectors was used to separate the macromolecules present in the beers and the molar mass (M) and molar mass distributions (MD) were determined. Macromolecular components were identified by enzymatic treatments with β-glucanase and proteinase K. The MD of β-glucan ranged from 10(6) to 10(8) g/mol. In addition, correlation between the beer's composition and foam stability was investigated (increased concentration of protein and β-glucan was associated with increased foam stability).
Extracting the $\\eta^\\prime$ meson mass from gluonic correlators in lattice QCD
Fukaya, H; Hashimoto, S; Kaneko, T
2015-01-01
Calculation of the eta-prime meson mass is a notoriously difficult problem, as it requires evaluation of the disconnected diagram which is costly and noisy. In this work, we use a gluonic operator to extract the eta-prime state after smearing the link variables through the Wilson flow. With this choice, one can avoid a large cancellation of pion contribution between the connected and disconnected diagrams. We obtain the eta-prime meson mass on lattices with three different lattice spacings and two physical volumes, which allow us to estimate its continuum and large volume limits.
Non-stationary Entanglement Entropy Flow in Mass-deformed ABJM Theory
Kim, Kyung Kiu; Park, Chanyong; Shin, Hyeonjoon
2014-01-01
We investigate a mass deformation effect on the renormalized entanglement entropy (REE) near the UV fixed point in (2+1)-dimensional field theory. In the context of the gauge/gravity duality, we use the Lin-Lunin-Maldacena (LLM) geometries corresponding to the vacua of the mass-deformed ABJM theory. We analytically compute the small mass effect for various droplet configurations and confirm in holographic point of view that the REE is not always stationary at the UV fixed point. Except that, other properties are consistent with the Zamolodchikov $c$-function proposed in (1+1)-dimensional conformal field theory.
Phase diagram of crushed powders
Bodard, Sébastien; Jalbaud, Olivier; Saurel, Richard; Burtschell, Yves; Lapebie, Emmanuel
2016-12-01
Compression of monodisperse powder samples in quasistatic conditions is addressed in a pressure range such that particles fragmentation occurs while the solid remains incompressible (typical pressure range of 1-300 MPa for glass powders). For a granular bed made of particles of given size, the existence of three stages is observed during compression and crush up. First, classical compression occurs and the pressure of the granular bed increases along a characteristic curve as the volume decreases. Then, a critical pressure is reached for which fragmentation begins. During the fragmentation process, the granular pressure stays constant in a given volume range. At the end of this second stage, 20%-50% of initial grains are reduced to finer particles, depending on the initial size. Then the compression undergoes the third stage and the pressure increases along another characteristic curve, in the absence of extra fragmentation. The present paper analyses the analogies between the phase transition in liquid-vapour systems and powder compression with crush-up. Fragmentation diagram for a soda lime glass is determined by experimental means. The analogues of the saturation pressure and latent heat of phase change are determined. Two thermodynamic models are then examined to represent the crush-up diagram. The first one uses piecewise functions while the second one is of van der Waals type. Both equations of state relate granular pressure, solid volume fraction, and initial particle diameter. The piecewise functions approach provides reasonable representations of the phase diagram while the van der Waals one fails.
Scheil-Gulliver Constituent Diagrams
Pelton, Arthur D.; Eriksson, Gunnar; Bale, Christopher W.
2017-03-01
During solidification of alloys, conditions often approach those of Scheil-Gulliver cooling in which it is assumed that solid phases, once precipitated, remain unchanged. That is, they no longer react with the liquid or with each other. In the case of equilibrium solidification, equilibrium phase diagrams provide a valuable means of visualizing the effects of composition changes upon the final microstructure. In the present study, we propose for the first time the concept of Scheil-Gulliver constituent diagrams which play the same role as that in the case of Scheil-Gulliver cooling. It is shown how these diagrams can be calculated and plotted by the currently available thermodynamic database computing systems that combine Gibbs energy minimization software with large databases of optimized thermodynamic properties of solutions and compounds. Examples calculated using the FactSage system are presented for the Al-Li and Al-Mg-Zn systems, and for the Au-Bi-Sb-Pb system and its binary and ternary subsystems.
Directory of Open Access Journals (Sweden)
S.K Ghosh
2015-01-01
Full Text Available The purpose of present investigation is to analyse bouyancy-driven radiation-convection flow past a moving vertical plate with reference to an optically dense medium in the presence of mass concentration, using Rosseland approximation permeated by a magnetic field. The flow is considered to be gray in the presence of free convection, mass transfer and radiation. An exact solution of the governing equations is obtained by applying the Laplace transform method. Numerical results of velocity distributions, shear stress, temperature distribution and mass concentration are presented graphically to give physical insight into the flow pattern.
Walsh, B.; Jolly, A. D.; Procter, J. N.
2016-09-01
On 6 August 2012 an eruption of the upper Te Maari vent Tongariro volcano and subsequent debris flow in the Mangatetipua channel created a debris dam and ephemeral lake. The lake reached its maximum volume of 50,000 m3 by 13 October, initiating dam breaching at 22:30 NZDT (11:30 UTC) after a period of intense rainfall. The breach eventually grew to 29 × 12 m, causing eroded debris flow sediment and water to remobilize as a lahar. The event, comprising multiple surges, lasted ~ 30 min, and displaced 57,000 m3 of remobilized sediment up to 4.5 km downstream. To determine the dynamics of the event, the seismic signals generated by the lahar were compared with active seismic source data collected in February 2013. The comparison used a common frequency band range of 3-10 Hz to compute amplitude for four near-field seismic stations. For periods with signal-to-noise ratios above 2.0, we obtained lahar amplitude distributions that match best the equivalent active source amplitudes within ~ 0.5 km of the dam breakout. The accumulated seismic energy of the lahar was estimated at 1.93 × 109 Nm, whereas the peak energy was 6.88 × 107 Nm. Results of this work may improve the characterization of future mass flow events in the Te Maari/Mangatetipua area through the calibration of seismic stations used in this study.
Operations space diagram for ECRH and ECCD
DEFF Research Database (Denmark)
Bindslev, H.
2004-01-01
A Clemmov-Mullaly-Allis (CMA) type diagram, the ECW-CMA diagram, for representing the operational possibilities of electron cyclotron heating and current drive (ECRH/ECCD) systems for fusion plasmas is presented. In this diagram, with normalized density and normalized magnetic field coordinates...
Di Federico, V.; Ciriello, V.
2011-12-01
Non-Newtonian fluid flow in porous media is of considerable interest in hydrology, chemical and petroleum engineering, and biofluid mechanics. We consider an infinite porous domain of plane (d=1), cylindrical (d=2) or semi-spherical geometry (d=3), having uniform permeability k and porosity Φ, initially at uniform pressure and saturated by a weakly compressible non-Newtonian fluid, and analyze the dynamics of the pressure variation generated within the domain by an instantaneous mass injection m0 in its origin. The fluid is described by a rheological power-law model of given consistency index H and flow behavior index n; the flow law is a modified Darcy's law depending on H, Φ, n. Coupling flow law and mass balance equations yields the nonlinear partial differential equation governing the pressure field; an analytical solution is derived in space r and time t as a function of a self-similar variable η=r/tβ(n). We revisit and expand the work in previous papers by providing a dimensionless general formulation and solution to the problem for d=1,2,3. When a shear-thinning fluid (nfluids; the front velocity is proportional to t(n-2)/2 in plane geometry, t(2n-3)/(3-n) in cylindrical geometry, and t(3n-4)/(4-2n) in semi-spherical geometry. The front position is a markedly increasing function of n and is inversely dependent on d; the pressure front advances at a slower rate for larger values of compressibility, higher injected mass and lower porosity. When pressure is considered, it is seen that an increase in d from 1 to 3 brings about an order of magnitude reduction. An increase in compressibility implies a significant decrease in pressure, especially at early times. To reflect the uncertainty inherent in values of the problem parameters, we then consider selected properties of fluid (flow behavior index n) and porous domain (permeability k, porosity Φ, and medium compressibility cp) as independent random variables with uniform probability distribution. The
Burgess, Karl; Creek, Darren; Dewsbury, Paul; Cook, Ken; Barrett, Michael P
2011-11-30
This work describes a novel application of capillary-flow ion chromatography mass spectrometry for metabolomic analysis, and comparison of the technique to octadecyl silica and hydrophilic interaction chromatography (HILIC)-based mass spectrometry. While liquid chromatography/mass spectrometry (LC/MS) is rapidly becoming the standard technique for metabolomic analysis, metabolomic samples are extremely heterogeneous, leading to a requirement for multiple methods of analysis and separation techniques to perform a 'global' metabolomic analysis. While C18 is suitable for hydrophobic metabolites and has been used extensively in pharmaceutical drug metabolism studies, HILIC is, in general, efficient at separating polar metabolites. Phosphorylated species and organic acids are challenging to analyse and effectively quantitate on both systems. There is therefore a requirement for an MS-compatible analytical technique that can separate negatively charged compounds, such as ion-exchange chromatography. Evaluation of capillary flow ion chromatography with electrolytic suppression was performed on a library of metabolite standards and was shown to effectively separate organic acids and sugar di- and tri-phosphates. Limits of detection for these compounds range from 0.01 to 100 pmol on-column. Application of capillary ion chromatography to a comparative analysis of energy metabolism in procyclic forms of the parasitic protozoan Trypanosoma brucei where cells were grown on glucose or proline as a carbon source was demonstrated to be more effective than HILIC for detection of the organic acids that comprise glucose central metabolism and the tricarboxylic acid (TCA) cycle.