WorldWideScience

Sample records for staggered herringbone micromixer

  1. Realization of a passive micromixer using herringbone structure

    Science.gov (United States)

    Whulanza, Yudan; Utomo, Muhammad S.; Hilman, Adam

    2018-02-01

    Micromixing is an important research area for a variety of applications in sensing and diagnostics. In this paper, we are trying to develop an overall understanding of the process of mixing by allowing two fluid flows to flow through various asymmetrical structures. We have successfully realized and compared the performance of different passive micromixer designs based on the idea of staggered herringbone micromixer. The herringbone structure is expected to affect the flow rate. We design few microchannels using varieties on velocity, height and distance between herringbone. The layout of the structure is based on the staggered herringbone bilayers where the layer is positioned on the bottom wall of the microchannel. From simulation and experiment, it is known that the height of the channel and herringbone structure affect the flow, and the most effective height of the main channel and herringbone structure is 0.3 and 0.14 mm (2:1 ratio).

  2. Efficient gas-liquid contact using microfluidic membrane devices with staggered herringbone mixers.

    Science.gov (United States)

    Femmer, Tim; Eggersdorfer, Max L; Kuehne, Alexander J C; Wessling, Matthias

    2015-08-07

    We describe a novel membrane based gas-liquid-contacting device with increased mass transport and reduced pressure loss by combining a membrane with a staggered herringbone static mixer. Herringbone structures are imposed on the microfluidic channel geometry via soft lithography, acting as mixers which introduce secondary flows at the membrane interface. Such flows include Dean vortices and Taylor flows generating effective mixing while improving mass transport and preventing concentration polarization in microfluidic channels. Furthermore, our static herringbone mixer membranes effectively reduce pressure losses leading to devices with enhanced transfer properties for microfluidic gas-liquid contact. We investigate the red blood cell distribution to tailor our devices towards miniaturised extracorporeal membrane oxygenation and improved comfort of patients with lung insufficiencies.

  3. Microfluidic Manufacturing of Polymeric Nanoparticles: Comparing Flow Control of Multiscale Structure in Single-Phase Staggered Herringbone and Two-Phase Reactors.

    Science.gov (United States)

    Xu, Zheqi; Lu, Changhai; Riordon, Jason; Sinton, David; Moffitt, Matthew G

    2016-12-06

    We compare the microfluidic manufacturing of polycaprolactone-block-poly(ethylene oxide) (PCL-b-PEO) nanoparticles (NPs) in a single-phase staggered herringbone (SHB) mixer and in a two-phase gas-liquid segmented mixer. NPs generated from two different copolymer compositions in both reactors and at three different flow rates, along with NPs generated using a conventional bulk method, are compared with respect to morphologies, dimensions, and internal crystallinities. Our work, the first direct comparison between alternate microfluidic NP synthesis methods, shows three key findings: (i) NP morphologies and dimensions produced in the bulk are different from those produced in a microfluidic mixer, whereas NP crystallinities produced in the bulk and in the SHB mixer are similar; (ii) NP morphologies, dimensions, and crystallinities produced in the single-phase SHB and two-phase mixers at the lowest flow rate are similar; and (iii) NP morphologies, dimensions, and crystallinities change with flow rate in the two-phase mixer but not in the single-phase SHB mixer. These findings provide new insights into the relative roles of mixing and shear in the formation and flow-directed processing of polymeric NPs in microfluidics, informing future reactor designs for manufacturing NPs of low polydispersity and controlled multiscale structure and function.

  4. Micromixer based on Taylor dispersion

    International Nuclear Information System (INIS)

    Yang, H; Nguyen, N-T; Huang, X

    2006-01-01

    This paper reports an analytical model, the fabrication and the characterization of a polymeric micromixer based on Taylor dispersion. Due to the distributed velocity field over the channel cross section, the effective dispersion in axial direction in a microchannel is much stronger than the pure molecular diffusion. In our work, squential segmentation was used in the micromixer for improving mixing in a microchannel. The micromixer was designed and fabricated based on lamination of five 100-μm-thick polymer sheets. Rubber valve seats were embedded between the forth and the fifth layers. The polymer layers were machined using a CO 2 laser. The lamination of the five layers was carried out by a commercial hot laminator (Aurora LM-450HC). External solenoid actuators are used for closing the valves at the mixer inlets. The experimental results confirm the effect of Taylor dispersion. Mixing ratio can be adjusted by pulse width modulation of the control signal of the solenoids

  5. Active micromixer using surface acoustic wave streaming

    Science.gov (United States)

    Branch,; Darren W. , Meyer; Grant D. , Craighead; Harold, G [Ithaca, NY

    2011-05-17

    An active micromixer uses a surface acoustic wave, preferably a Rayleigh wave, propagating on a piezoelectric substrate to induce acoustic streaming in a fluid in a microfluidic channel. The surface acoustic wave can be generated by applying an RF excitation signal to at least one interdigital transducer on the piezoelectric substrate. The active micromixer can rapidly mix quiescent fluids or laminar streams in low Reynolds number flows. The active micromixer has no moving parts (other than the SAW transducer) and is, therefore, more reliable, less damaging to sensitive fluids, and less susceptible to fouling and channel clogging than other types of active and passive micromixers. The active micromixer is adaptable to a wide range of geometries, can be easily fabricated, and can be integrated in a microfluidic system, reducing dead volume. Finally, the active micromixer has on-demand on/off mixing capability and can be operated at low power.

  6. Experimental study of heat transfer and pressures drops for cans with spiral herring-bone fins

    International Nuclear Information System (INIS)

    Pelce, J.; Francois, S.; Houseaux, O.; Pierre, B.

    1964-01-01

    Cans fitted with herring-bone fins are used for cooling uranium in certain nuclear reactor. By herring-bone is meant a staggered arrangement of the fins which have a plane of symmetry parallel to the general direction of liquid flow. The main geometrical parameter are then: the number of fins, the number of herring-bones, the angle of inclination of the fins with respect to the can axis, the dimensions of the fins, the can diameter and the channel diameter. The research is essentially experimental. The test are of three types: full size tests, in conditions approaching those in the reactor (constant flux, CO 2 under pressure); full size tests but with a constant wall temperature, much easier to set up, and intended to distinguish rapidly between the merits of the various types of can; large-scale tests with air at atmospheric pressure for studying the phenomena in more detail. For each can tried out there is a corresponding pressure drop coefficient, a mean thermal exchange coefficient Mo-bar and a minimum exchange coefficient Mo min and Mo-bar are related by the expression Mo min = Mo-bar * f c * f, where f c and f are respectively circumferential and longitudinal singularity factor determined from a statistical study of all the temperatures measured for each can. The results are presented in about thirty tables and figures the most noteworthy results being summarized in the conclusion. (authors) [fr

  7. Flow over bio-inspired 3D herringbone wall riblets

    Science.gov (United States)

    Chen, Huawei; Rao, Fugang; Shang, Xiaopeng; Zhang, Deyuan; Hagiwara, Ichiro

    2014-03-01

    Under the inspiration of small riblets of shark skin, the microgroove drag reduction riblets whose direction set along fluid flow have been widely investigated. Herringbone-type riblets of bird flight feather are seldom exploited although bird also has excellent flight performance. Inspired from the flight feather, novel bio-inspired plane-3D (p-3D) and spatial-3D (s-3D) herringbone wall riblets are proposed. Through experiment measurement of drag reduction in water tunnel, maximum drag reduction of p-3D and s-3D herringbone riblets was about 17 and 20 %, higher than traditional microgroove riblets. Moreover, significant change of drag reduction was also found by change of the angle between herringbone riblets. In particular, maximum drag reduction occurred as angle between herringbone riblets was about 60° close to real flight feather, which indicates that microstructure of bird flight feather has great impact on flight performance.

  8. The Effects of Micromixing Two Solutions of Two Concentrations in a Two Tier PDMS Micromixer

    Science.gov (United States)

    Sundra, Sargunan; Fhong Soon, Chin; Zainal, Nurfarina; Sek Tee, Kian; Ahmad, Nornabihah; Gan, Siew Hua

    2017-08-01

    Micromixing technology has drastically advanced in the past few decades. Micromixers are one of the elements in integrated microfluidic systems for chemical, analytical chemistry, pharmaceutical, and biological applications. In this study, two tier micromixer was used to mix and dilute two solutions of similar and different concentration in order to investigate performance of micromixer’s mixing. This paper presents the fabrication of a designed micromixer using polydimethylsiloxane (PDMS) and vinyl tape methods which reduce time, cost and complexity of prototyping. The serpentine structure of the microchannels was designed to enhance both mixing and dilution. Two types of food dyes and distilled water were used to investigate the mixing performance of the micromixer followed by spectrophotometry analysis. It is observed that the single dye solution and distilled water shows better mixing performance compared to the micromixing of two dye solutions which was supported by the diffusion theory. 2.00 ml/min was the optimum flow rate that allow optimum mixing and dilution between two different concentrated liquids.

  9. Optimization of Grooved Micromixer for Microengineering Technologies

    DEFF Research Database (Denmark)

    Sabotin, I.; Tristo, G.; Bissacco, Giuliano

    2013-01-01

    with a modified Slanted Groove Micromixer (SGM). A SGM prototype was machined by micro electrical discharge milling (EDM) technology. The simulation results were experimentally verified with flow visualization and a good agreement was observed. Due to simple 2.5D geometry and efficient mixing properties...

  10. A flexible layout design method for passive micromixers.

    Science.gov (United States)

    Deng, Yongbo; Liu, Zhenyu; Zhang, Ping; Liu, Yongshun; Gao, Qingyong; Wu, Yihui

    2012-10-01

    This paper discusses a flexible layout design method of passive micromixers based on the topology optimization of fluidic flows. Being different from the trial and error method, this method obtains the detailed layout of a passive micromixer according to the desired mixing performance by solving a topology optimization problem. Therefore, the dependence on the experience of the designer is weaken, when this method is used to design a passive micromixer with acceptable mixing performance. Several design disciplines for the passive micromixers are considered to demonstrate the flexibility of the layout design method for passive micromixers. These design disciplines include the approximation of the real 3D micromixer, the manufacturing feasibility, the spacial periodic design, and effects of the Péclet number and Reynolds number on the designs obtained by this layout design method. The capability of this design method is validated by several comparisons performed between the obtained layouts and the optimized designs in the recently published literatures, where the values of the mixing measurement is improved up to 40.4% for one cycle of the micromixer.

  11. Developing the EFL Students’ Reading Comprehension By Employing Herringbone Technique

    Directory of Open Access Journals (Sweden)

    Yunisrina Qismullah Yusuf

    2016-11-01

    Full Text Available This research aims to find out whether Herringbone Technique can developEFL students’ reading comprehension or not, especially in finding the main idea and supporting details in a recount text. The literature notes that Herringbone is known to be one of the techniques that can helpstudents to find important information and main idea in a text by seeking for answers on six comprehension questions on a diagram, viewed such as a fish’s skeleton. The sample of this research was 30 second grade junior high school students. The researchers employed simple random sampling to choose the sample. It further used the quantitative experimental approach with the pre-experimental design in the form of one group pre-test-post-test design.Pre-test was given before treatments, while post-test was given after the students were taught reading by using the Herringbone Technique. Each pre-test and post-test consisted of ten questions. The statistical formulas were used to analyze the data from the students tests’ scores. The mean score of pre-test was 59 and the post-test was 76. Futhermore, the result of t-test was 10.15, while the critical value of 0.05 significant level was 2.045, with the degree of freedom of 29. Since t-test (10.15 was higher than t-table (2.045, this study concludes that this technique could increase the EFL students’ reading comprehension.Despite in practice the researchers found that this technique decreased the students’ efforts in note-taking, however it did not inhibited them in obtaining improved scores in their reading tests.

  12. Operation of direct channel microchannel plates in the ''herringbone'' scheme

    International Nuclear Information System (INIS)

    Sorokin, O.M.

    1982-01-01

    Operation of two series connection microchannel plates (MCP) in the monoelectron mode is investigat4eed. MCP of 0.8 mm thick and having 28 mm diameter were investigated. The channel cross section is equal to approximately μm, channel angle is 7 deg. A formula for the noise power factor in the mode of channel saturation is derived. The experimental data processing by collector pulse amplitude distribution results in the conclusion on possibility of sharp drop of MCP amplification noise factor at transition into the saturation mode. Shown is the principal possibility of obtaining the amplitude resolution up to 0.05 and on the base of it - application of ''herringbone'' scheme as an amplitude detector. A possibility of detecting 1-, 2-, 3- and 4-electron photoemission events in the ultraviolet spectrum region with < or approximately 5% resolution is illustrated. It is shown that the ''herringbone'' scheme is comparatively simple in operation despite a centain difficulty in gap regulation and it does require superhigh vacuum or fine technology and it is stable in operation at the pressure of approximately 0, 3 mPa

  13. Inertial focusing and passive micro-mixing techniques for rare cells capturing microfluidic platform

    Science.gov (United States)

    Phadke, Manisha; Shaner, Sebastian; Shah, Shreyas; Rodriguez, Ygnacio; Wibowo, Denni; Whulanza, Yudan; Teriete, Peter; Allen, Jeff; Kassegne, Sam

    2018-02-01

    Isolation and capture of rare cells continues to be a daunting task that is still looking for an innovative and efficient method. While a variety of approaches have been suggested over the past several years, immunocapturing in a microfluidic platform carries a substantial promise as shown by recent published works. In this paper, we introduced a combination of inertial focusing and passive micro-mixing through 3D chevron-type features in a microchannel to induce chaotic mixing within antibody-coated microchannels and, ultimately, promote rare cell capture. The device introduced in this work contains curved microchannels that consist of a series of staggered chevron grooves. The curved channels enable inertial focusing while the chevron grooves allow for chaotic mixing. The microfluidics platform microfabricated through soft lithography has a polydimethylsiloxane (PDMS) foundation and was thinly coated with an alginate hydrogel derivatized with streptavidin. We submitted that our qualitative and quantitative results demonstrated the potentials in advancements in rare cell isolation through this integration of two techniques.

  14. A novel passive micromixer: lamination in a planar channel system

    DEFF Research Database (Denmark)

    Tofteberg, T.; Skolimowski, Maciej; Andreassen, E.

    2010-01-01

    A novel passive micromixer concept is presented. The working principle is to make a controlled 90 degrees rotation of a flow cross-section followed by a split into several channels; the now in each of these channels is rotated a further 90 degrees before a recombination doubles the interfacial ar...

  15. Static micromixers based on large-scale industrial mixer geometry.

    Science.gov (United States)

    Bertsch, A; Heimgartner, S; Cousseau, P; Renaud, P

    2001-09-01

    Mixing liquids at the micro-scale is difficult because the low Reynolds numbers in microchannels and in microreactors prohibit the use of conventional mixing techniques based on mechanical actuators and induce turbulence. Static mixers can be used to solve this mixing problem. This paper presents micromixers with geometries very close to conventional large-scale static mixers used in the chemical and food-processing industry. Two kinds of geometries have been studied. The first type is composed of a series of stationary rigid elements that form intersecting channels to split, rearrange and combine component streams. The second type is composed of a series of short helix elements arranged in pairs, each pair comprised of a right-handed and left-handed element arranged alternately in a pipe. Micromixers of both types have been designed by CAD and manufactured with the integral microstereolithography process, a new microfabrication technique that allows the manufacturing of complex three-dimensional objects in polymers. The realized mixers have been tested experimentally. Numerical simulations of these micromixers using the computational fluid dynamics (CFD) program FLUENT are used to evaluate the mixing efficiency. With a low pressure drop and good mixing efficiency these truly three-dimensional micromixers can be used for mixing of reactants or liquids containing cells in many microTAS applications.

  16. Biosensor enhancement using grooved micromixers: Part I, numerical studies

    Czech Academy of Sciences Publication Activity Database

    Lynn, Nicholas Scott; Homola, Jiří

    2015-01-01

    Roč. 87, č. 11 (2015), s. 5516-5523 ISSN 0003-2700 R&D Projects: GA ČR(CZ) GBP205/12/G118 Institutional support: RVO:67985882 Keywords : Numerical methods * Micromixers * Analytes Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 5.886, year: 2015

  17. Modeling and Analysis of the Static Characteristics and Dynamic Responses of Herringbone-grooved Thrust Bearings

    Science.gov (United States)

    Yu, Yunluo; Pu, Guang; Jiang, Kyle

    2017-12-01

    This paper describes a theoretical investigation of static and dynamic characteristics of herringbone-grooved air thrust bearings. Firstly, Finite Difference Method (FDM) and Finite Volume Method (FVM) are used in combination to solve the non-linear Reynolds equation and to find the pressure distribution of the film and the total loading capacity of the bearing. The influence of design parameters on air film gap characteristics, including the air film thickness, depth of the groove and rotating speed, are analyzed based on the FDM model. The simulation results show that hydrostatic thrust bearings can achieve a better load capacity with less air consumption than herringbone grooved thrust bearings at low compressibility number; herringbone grooved thrust bearings can achieve a higher load capacity but with more air consumption than hydrostatic thrust bearing at high compressibility number; herringbone grooved thrust bearings would lose stability at high rotating speeds, and the stability increases with the depth of the grooves.

  18. Improvement study for the dry-low-NOx hydrogen micromix combustion technology

    OpenAIRE

    A. Haj Ayed; K. Kusterer; H.H.-W. Funke; J. Keinz; C. Striegan; D. Bohn

    2015-01-01

    The dry-low-NOx (DLN) micromix combustion principle is developed for the low emission combustion of hydrogen in an industrial gas turbine APU GTCP 36-300. The further decrease of NOx emissions along a wider operation range with pure hydrogen supports the introduction of the micromix technology to industrial applications. Experimental and numerical studies show the successful advance of the DLN micromix combustion to extended DLN operation range. The impact of the hydrogen fuel properties on t...

  19. Staggering but not knocked out

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2012-11-01

    Italy's PV market is staggering like a boxer almost knocked out. It has been hit hard by the country's deep economic recession. Conto Energia V has been yet another blow with cuts of up to 40 % in the solar feed-in tariffs. But the situation is not hopeless.

  20. Taste changing in staggered quarks

    International Nuclear Information System (INIS)

    Quentin Mason

    2004-01-01

    The authors present results from a systematic perturbative investigation of taste-changing in improved staggered quarks. They show one-loop taste-changing interactions can be removed perturbatively by an effective four-quark term and calculate the necessary coefficients

  1. Development of small-volume, microfluidic chaotic mixers for future application in two-dimensional liquid chromatography

    NARCIS (Netherlands)

    Ianovska, Margaryta A.; Mulder, Patty P. M. F. A.; Verpoorte, Elisabeth

    2017-01-01

    We report a microfluidic chaotic micromixer with staggered herringbone grooves having a geometry optimized for fast mobile-phase modification at the interface of a two-dimensional liquid chromatography system. The volume of the 300 mm mixers is 1.6 microliters and they provide mixing within 26 s at

  2. On staggered indecomposable Virasoro modules

    International Nuclear Information System (INIS)

    Kytoelae, Kalle; Ridout, David

    2009-06-01

    In this article, certain indecomposable Virasoro modules are studied. Specifically, the Virasoro mode L0 is assumed to be non-diagonalisable, possessing Jordan blocks of rank two. Moreover, the module is further assumed to have a highest weight submodule, the ''left module'', and that the quotient by this submodule yields another highest weight module, the ''right module''. Such modules, which have been called staggered, have appeared repeatedly in the logarithmic conformal field theory literature, but their theory has not been explored in full generality. Here, such a theory is developed for the Virasoro algebra using rather elementary techniques. The focus centres on two different but related questions typically encountered in practical studies: How can one identify a given staggered module, and how can one demonstrate the existence of a proposed staggered module. Given just the values of the highest weights of the left and right modules, themselves subject to simple necessary conditions, invariants are defined which together with the knowledge of the left and right modules uniquely identify a staggered module. The possible values of these invariants form a vector space of dimension zero, one or two, and the structures of the left and right modules limit the isomorphism classes of the corresponding staggered modules to an affine subspace (possibly empty). The number of invariants and affine restrictions is purely determined by the structures of the left and right modules. Moreover, in order to facilitate applications, the expressions for the invariants and restrictions are given by formulae as explicit as possible (they generally rely on expressions for Virasoro singular vectors). Finally, the text is liberally peppered throughout with examples illustrating the general concepts. These have been carefully chosen for their physical relevance or for the novel features they exhibit. (orig.)

  3. On staggered indecomposable Virasoro modules

    Science.gov (United States)

    Kytölä, Kalle; Ridout, David

    2009-12-01

    In this article, certain indecomposable Virasoro modules are studied. Specifically, the Virasoro mode L0 is assumed to be nondiagonalizable, possessing Jordan blocks of rank 2. Moreover, the module is further assumed to have a highest weight submodule, the "left module," and that the quotient by this submodule yields another highest weight module, the "right module." Such modules, which have been called staggered, have appeared repeatedly in the logarithmic conformal field theory literature, but their theory has not been explored in full generality. Here, such a theory is developed for the Virasoro algebra using rather elementary techniques. The focus centers on two different but related questions typically encountered in practical studies: How can one identify a given staggered module, and how can one demonstrate the existence of a proposed staggered module. Given just the values of the highest weights of the left and right modules, themselves subject to simple necessary conditions, invariants are defined which together with the knowledge of the left and right modules uniquely identify a staggered module. The possible values of these invariants form a vector space of dimension 0, 1, or 2, and the structures of the left and right modules limit the isomorphism classes of the corresponding staggered modules to an affine subspace (possibly empty). The number of invariants and affine restrictions is purely determined by the structures of the left and right modules. Moreover, in order to facilitate applications, the expressions for the invariants and restrictions are given by formulas as explicit as possible (they generally rely on expressions for Virasoro singular vectors). Finally, the text is liberally peppered throughout with examples illustrating the general concepts. These have been carefully chosen for their physical relevance or for the novel features they exhibit.

  4. On staggered indecomposable Virasoro modules

    Energy Technology Data Exchange (ETDEWEB)

    Kytoelae, Kalle [Geneve Univ. (Switzerland); Ridout, David [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2009-06-15

    In this article, certain indecomposable Virasoro modules are studied. Specifically, the Virasoro mode L0 is assumed to be non-diagonalisable, possessing Jordan blocks of rank two. Moreover, the module is further assumed to have a highest weight submodule, the ''left module'', and that the quotient by this submodule yields another highest weight module, the ''right module''. Such modules, which have been called staggered, have appeared repeatedly in the logarithmic conformal field theory literature, but their theory has not been explored in full generality. Here, such a theory is developed for the Virasoro algebra using rather elementary techniques. The focus centres on two different but related questions typically encountered in practical studies: How can one identify a given staggered module, and how can one demonstrate the existence of a proposed staggered module. Given just the values of the highest weights of the left and right modules, themselves subject to simple necessary conditions, invariants are defined which together with the knowledge of the left and right modules uniquely identify a staggered module. The possible values of these invariants form a vector space of dimension zero, one or two, and the structures of the left and right modules limit the isomorphism classes of the corresponding staggered modules to an affine subspace (possibly empty). The number of invariants and affine restrictions is purely determined by the structures of the left and right modules. Moreover, in order to facilitate applications, the expressions for the invariants and restrictions are given by formulae as explicit as possible (they generally rely on expressions for Virasoro singular vectors). Finally, the text is liberally peppered throughout with examples illustrating the general concepts. These have been carefully chosen for their physical relevance or for the novel features they exhibit. (orig.)

  5. High-Throughput Fabrication of Nanocomplexes Using 3D-Printed Micromixers

    DEFF Research Database (Denmark)

    Bohr, Adam; Boetker, Johan; Wang, Yingya

    2017-01-01

    printing, which enable a continuous and industrial scale production of nanocomplexes formed by electrostatic complexation, using the polymers poly(diallyldimethylammonium chloride) and poly(sodium 4-styrenesulfonate). Several parameters including polymer concentration, flow rate, and flow ratio were......3D printing allows a rapid and inexpensive manufacturing of custom made and prototype devices. Micromixers are used for rapid and controlled production of nanoparticles intended for therapeutic delivery. In this study, we demonstrate the fabrication of micromixers using computational design and 3D...... via bulk mixing. Moreover, each micromixer could process more than 2 liters per hour with unaffected performance and the setup could easily be scaled-up by aligning several micromixers in parallel. This demonstrates that 3D printing can be used to prepare disposable high-throughput micromixers...

  6. Numerical analysis and comparison of three types of herringbone frame structure for highway subgrade slopes protection

    Science.gov (United States)

    Nie, Yihua; Tang, Saiqian; Xu, Yang; Mao, Kunli

    2018-04-01

    In order to obtain mechanical response distribution of herringbone frame structure for highway subgrade slopes protection and select the best structure type, 3D numerical models of three types herringbone frame structure were established and analyzed in finite element software ANSYS. Indoor physical model of soil slope protected by herringbone frame structure was built and mechanical response of the frame structure was measured by loading tests. Numerical results indicate slope foot is the stress most disadvantageous location. Comparative analysis shows that structure composed of mortar rubble base layer and precast concrete blocks paving layer is the best one for resisting deformation and structure with cement mortar base layer and precast concrete blocks paving layer is the best one for being of low stress.

  7. Fin-and-tube heat exchanger enhancement with a combined herringbone and vortex generator design

    DEFF Research Database (Denmark)

    Välikangas, Turo; Singh, Shobhana; Sørensen, Kim

    2018-01-01

    Vortex generators (VGs) are the most commonly investigated enhancement methods in the field of improved heat exchangers. The aim of present work is to study the effect of VGs in a fin-and-tube heat exchanger (FTHE) with herringbone fin shape. The delta winglet VG design with length (s) and height...... (H) is selected based on previous studies. The investigated VG design is simple and considered realistic from the manufacturing point of view. The combined enhancement with herringbone fin and the VG is evaluated by simulating the conjugate heat transfer and the air flow. The structured mesh...... transfer in the herringbone fin but also decrease the pressure drop. The highest and longest investigated VG design is found to perform the best because of its ability to delay the flow detachment from the tube, to feed high kinetic energy flow to the recirculation zone and to create longitudinal vortices...

  8. Method for the production of ultrafine particles by electrohydrodynamic micromixing

    Science.gov (United States)

    DePaoli, David W.; Hu, Zhong Cheng; Tsouris, Constantinos

    2001-01-01

    The present invention relates to a method for the rapid production of homogeneous, ultrafine inorganic material via liquid-phase reactions. The method of the present invention employs electrohydrodynamic flows in the vicinity of an electrified injector tube placed inside another tube to induce efficient turbulent mixing of two fluids containing reactive species. The rapid micromixing allows liquid-phase reactions to be conducted uniformly at high rates. This approach allows continuous production of non-agglomerated, monopispersed, submicron-sized, sphere-like powders.

  9. Staggering towards a calculation of weak amplitudes

    Energy Technology Data Exchange (ETDEWEB)

    Sharpe, S.R.

    1988-09-01

    An explanation is given of the methods required to calculate hadronic matrix elements of the weak Hamiltonians using lattice QCD with staggered fermions. New results are presented for the 1-loop perturbative mixing of the weak interaction operators. New numerical techniques designed for staggered fermions are described. A preliminary result for the kaon B parameter is presented. 24 refs., 3 figs.

  10. Staggering towards a calculation of weak amplitudes

    International Nuclear Information System (INIS)

    Sharpe, S.R.

    1988-09-01

    An explanation is given of the methods required to calculate hadronic matrix elements of the weak Hamiltonians using lattice QCD with staggered fermions. New results are presented for the 1-loop perturbative mixing of the weak interaction operators. New numerical techniques designed for staggered fermions are described. A preliminary result for the kaon B parameter is presented. 24 refs., 3 figs

  11. Tool kit for staggered fermions

    International Nuclear Information System (INIS)

    Kilcup, G.W.; Sharpe, S.R.

    1986-01-01

    The symmetries of staggered fermions are analyzed both discrete and continuous. Tools are presented that allow a simple decomposition of representations of the continuum symmetries into representations of the discrete lattice symmetries, both at zero and non-zero spatial momenta. These tools are used to find the lattice transcriptions of the operators that appear in the weak interaction Hamiltonian. The lattice Ward Identities are derived that follow from the single partially conserved axial symmetry. Using these identities, the lattice equivalents of the continuum PCAC relations are found. Combining all these tools, Ward Identities are obtained, for the matrix elements of the weak interaction Hamiltonian, from which the behavior of the matrix elements as the pion and kaon masses vanish are derived. The same behavior as in the continuum is found

  12. Numerical Analysis Of Mixing Under Low And High Frequency Pulsations At Serpentine Micromixers

    Directory of Open Access Journals (Sweden)

    Malecha Ziemowit M.

    2014-09-01

    Full Text Available The numerical investigation of the mixing process in complex geometry micromixers, as a function of various inlet conditions and various micromixer vibrations, was performed. The examined devices were two-dimensional (2D and three-dimensional (3D types of serpentine micromixers with two inlets. Entering fluids were perturbed with a wide range of the frequency (0 - 50 Hz of pulsations. Additionally, mixing fluids also entered in the same or opposite phase of pulsations. The performed numerical calculations were 3D to capture the proximity of all the walls, which has a substantial influence on microchannel flow. The geometry of the 3D type serpentine micromixer corresponded to the physically existing device, characterised by excellent mixing properties but also a challenging production process (Malecha et al., 2009. It was shown that low-frequency perturbations could improve the average mixing efficiency of the 2D micromixer by only about 2% and additionally led to a disadvantageously non-uniform mixture quality in time. It was also shown that high-frequency mixing could level these fluctuations and more significantly improve the mixing quality. In the second part of the paper a faster and simplified method of evaluation of mixing quality was introduced. This method was based on calculating the length of the contact interface between mixing fluids. It was used to evaluate the 2D type serpentine micromixer performance under various types of vibrations and under a wide range of vibration frequencies.

  13. Xurography as a Rapid Fabrication Alternative for Point-of-Care Devices: Assessment of Passive Micromixers

    Directory of Open Access Journals (Sweden)

    J. Israel Martínez-López

    2016-05-01

    Full Text Available Despite the copious amount of research on the design and operation of micromixers, there are few works regarding manufacture technology aimed at implementation beyond academic environments. This work evaluates the viability of xurography as a rapid fabrication tool for the development of ultra-low cost microfluidic technology for extreme Point-of-Care (POC micromixing devices. By eschewing photolithographic processes and the bulkiness of pumping and enclosure systems for rapid fabrication and passively driven operation, xurography is introduced as a manufacturing alternative for asymmetric split and recombine (ASAR micromixers. A T-micromixer design was used as a reference to assess the effects of different cutting conditions and materials on the geometric features of the resulting microdevices. Inspection by stereographic and confocal microscopy showed that it is possible to manufacture devices with less than 8% absolute dimensional error. Implementation of the manufacturing methodology in modified circular shape- based SAR microdevices (balanced and unbalanced configurations showed that, despite the precision limitations of the xurographic process, it is possible to implement this methodology to produce functional micromixing devices. Mixing efficiency was evaluated numerically and experimentally at the outlet of the microdevices with performances up to 40%. Overall, the assessment encourages further research of xurography for the development of POC micromixers.

  14. The Influence of Herringbone Technique Towards the Reading Comprehension of the Second Year Students of SMPN 4 Siak Hulu

    OpenAIRE

    Yuzulia, Irza; ', Mahdum Ph. D; ', Eliwarti, M. App.ling

    2017-01-01

    This pre-experimental research aimed to find out whether there is significant influence of students' reading comprehension after using Herringbone Technique in teaching reading at the second year of SMPN 4 Siak Hulu. Thus, the problem to be discussed is whether or not there is any significant influence of the students' reading comprehension after using Herringbone Technique in teaching reading at the second year of SMPN 4 Siak Hulu. The design of the research was one group pretest-posttest de...

  15. A novel micro-mixer with a quasi-active rotor: fabrication and design improvement

    Science.gov (United States)

    Kim, Yongdae; Lee, Jongkwang; Kwon, Sejin

    2009-10-01

    In the present paper, a novel micro-mixer with a quasi-active rotor for micro-plant applications is proposed and design considerations for the improvement of the mixing performance of the proposed micro-mixer are derived. The proposed micro-rotor mixer combines an active micro-mixer with a passive micro-mixer. The micro-rotor, which is a moving part of an active micro-mixer, is added to the micro-chamber of a passive micro-mixer. The micro-rotor was rotated by inflows tangential to the chamber, causing strong perturbations. Two models of the micro-rotor mixer were fabricated with six layers of photosensitive glass which were individually fabricated and thermally bonded together. Improvement in the design of the micro-rotor mixer was achieved after the fabrication and experimental testing of the first model. In the design of the second model, the channel width and the rotor diameter were diminished and the number of rotor blades was increased from four to five. Through these design improvements, the micro-rotor started rotating at a lower Reynolds number; the rotor rotated at Re 1000 in the first model, whereas it did so at Re 200 in the second model. The mixing efficiency values of the micro-mixers were measured using an image analysis method. In the results, the mixing performance was dominated by molecular diffusion in the low Reynolds number region. On the other hand, convection flows such as twisted flows and Coanda flows dominated the mixing performance in the higher Reynolds number region. In the upper Reynolds number region, the micro-rotor was rotated and strong perturbations were induced. The mixing efficiency values of the micro-rotor mixers were found to exceed 90% when the rotor was rotated.

  16. Experimental and numerical investigations of the dry-low-NOx hydrogen micromix combustion chamber of an industrial gas turbine

    Directory of Open Access Journals (Sweden)

    A. Haj Ayed

    2015-09-01

    The study reveals great potential for the successful application of numerical flow simulation to predict flame structure and NOx emission level of micromix hydrogen combustion, help understanding the flow phenomena related with the micromixing, reaction zone and NOx formation and support further optimization of the burner performance.

  17. CFD based exploration of the dry-low-NOx hydrogen micromix combustion technology at increased energy densities

    Directory of Open Access Journals (Sweden)

    A. Haj Ayed

    2017-03-01

    The study reveals great optimization potential of the micromix combustion technology with respect to the DLN characteristics and gives insight into the impact of geometry modifications on flame structure and NOx emission. This allows to further increase the energy density of the micromix burners and to integrate this technology in industrial gas turbines.

  18. Production of Biodiesel from Waste Vegetable Oil via KM Micromixer

    Directory of Open Access Journals (Sweden)

    M. F. Elkady

    2015-01-01

    Full Text Available The production of biodiesel from waste vegetable oils through its pretreatment followed by transesterification process in presence of methanol was investigated using a KM micromixer reactor. The parameters affecting biodiesel production process such as alcohol to oil molar ratio, catalyst concentration, the presence of tetrahydrofuran (THF as a cosolvent, and the volumetric flow rates of inlet fluids were optimized. The properties of the produced biodiesel were compared with its parent waste oil through different characterization techniques. The presence of methyl ester groups at the produced biodiesel was confirmed using both the gas chromatography-mass spectrometry (GC-MS and the infrared spectroscopy (FT-IR. Moreover, the thermal analysis of the produced biodiesel and the comparable waste oil indicated that the product after the transesterification process began to vaporize at 120°C which makes it lighter than its parent oil which started to vaporize at around 300°C. The maximum biodiesel production yield of 97% was recorded using 12 : 1 methanol to oil molar ratio in presence of both 1% NaOH and THF/methanol volume ratio 0.3 at 60 mL/h flow rate.

  19. Improvement study for the dry-low-NOx hydrogen micromix combustion technology

    Directory of Open Access Journals (Sweden)

    A. Haj Ayed

    2015-09-01

    Full Text Available The dry-low-NOx (DLN micromix combustion principle is developed for the low emission combustion of hydrogen in an industrial gas turbine APU GTCP 36-300. The further decrease of NOx emissions along a wider operation range with pure hydrogen supports the introduction of the micromix technology to industrial applications. Experimental and numerical studies show the successful advance of the DLN micromix combustion to extended DLN operation range. The impact of the hydrogen fuel properties on the combustion principle and aerodynamic flame stabilization design laws, flow field, flame structure and emission characteristics is investigated by numerical analysis using an eddy dissipation concept combustion model and validated against experimental results.

  20. Rapid Fabrication of Disposable Micromixing Arrays Using Xurography and Laser Ablation

    Directory of Open Access Journals (Sweden)

    J. Israel Martínez-López

    2017-05-01

    Full Text Available We assessed xurography and laser ablation for the manufacture of passive micromixers arrays to explore the scalability of unconventional manufacture technologies that could be implemented under the restrictions of the Point of Care for developing countries. In this work, we present a novel split-and-recombine (SAR array design adapted for interfacing standardized dispensing (handheld micropipette and sampling (microplate reader equipment. The design was patterned and sealed from A4 sized vinyl sheets (polyvinyl chloride, employing low-cost disposable materials. Manufacture was evaluated measuring the dimensional error with stereoscopic and confocal microscopy. The micromixing efficiency was estimated using a machine vision system for passive driven infusion provided by micropippetting samples of dye and water. It was possible to employ rapid fabrication based on xurography to develop a four channel asymmetric split-and-recombine (ASAR micromixer with mixing efficiencies ranging from 43% to 65%.

  1. Bifurcation analysis of an aerodynamic journal bearing system considering the effect of stationary herringbone grooves

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.-C. [Department of Mechanical Engineering, Far East College, 49, Hsin-Shih, Tainan 744, Taiwan (China)]. E-mail: ccwang@cc.fec.edu.tw

    2007-08-15

    This paper investigates the bifurcation and nonlinear behavior of an aerodynamic journal bearing system taking into account the effect of stationary herringbone grooves. A finite difference method based on the successive over relation approach is employed to solve the Reynolds' equation. The analysis reveals a complex dynamical behavior comprising periodic and quasi-periodic responses of the rotor center. The dynamic behavior of the bearing system varies with changes in the bearing number and rotor mass. The results of this study provide a better understanding of the nonlinear dynamics of aerodynamic grooved journal bearing systems.

  2. Bifurcation analysis of an aerodynamic journal bearing system considering the effect of stationary herringbone grooves

    International Nuclear Information System (INIS)

    Wang, C.-C.

    2007-01-01

    This paper investigates the bifurcation and nonlinear behavior of an aerodynamic journal bearing system taking into account the effect of stationary herringbone grooves. A finite difference method based on the successive over relation approach is employed to solve the Reynolds' equation. The analysis reveals a complex dynamical behavior comprising periodic and quasi-periodic responses of the rotor center. The dynamic behavior of the bearing system varies with changes in the bearing number and rotor mass. The results of this study provide a better understanding of the nonlinear dynamics of aerodynamic grooved journal bearing systems

  3. Weak interaction matrix elements with staggered fermions

    International Nuclear Information System (INIS)

    Sharpe, S.R.

    1986-08-01

    An overview of the results of the Los Alamos Advanced Computing Group is given. The theory behind the measurement of Weak Interaction Matrix Elements using staggered fermions is presented, and contrasted with that for Wilson fermions. This is followed by a preliminary discussion of numerical results on a 12 3 x 30 lattice. 10 refs., 4 figs

  4. Kaon decay amplitudes using staggered fermions

    International Nuclear Information System (INIS)

    Sharpe, S.R.

    1986-12-01

    A status report is given of an attempt, using staggered fermions to calculate the real and imaginary parts of the amplitudes for K → ππ,. Semi-quantitative results are found for the imaginary parts, and these suggest that ε' might be smaller than previously expected in the standard model

  5. Numerical investigation on layout optimization of obstacles in a three-dimensional passive micromixer.

    Science.gov (United States)

    Chen, Xueye; Zhao, Zhongyi

    2017-04-29

    This paper aims at layout optimization design of obstacles in a three-dimensional T-type micromixer. Numerical analysis shows that the direction of flow velocity change constantly due to the obstacles blocking, which produces the chaotic convection and increases species mixing effectively. The orthogonal experiment method was applied for determining the effects of some key parameters on mixing efficiency. The weights in the order are: height of obstacles > geometric shape > symmetry = number of obstacles. Based on the optimized results, a multi-units obstacle micromixer was designed. Compared with T-type micromixer, the multi-units obstacle micromixer is more efficient, and more than 90% mixing efficiency were obtained for a wide range of peclet numbers. It can be demonstrated that the presented optimal design method of obstacles layout in three-dimensional microchannels is a simple and effective technology to improve species mixing in microfluidic devices. The obstacles layout methodology has the potential for applications in chemical engineering and bioengineering. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Flow Characterization in T-Shaped and Cross-Shaped Micromixers

    Czech Academy of Sciences Publication Activity Database

    Ait Mouheb, N.; Montillet, A.; Solliec, C.; Havlica, Jaromír; Legentilhomme, P.; Comiti, J.; Tihon, Jaroslav

    2011-01-01

    Roč. 10, č. 6 (2011), s. 1185-1197 ISSN 1613-4982 Institutional research plan: CEZ:AV0Z40720504 Keywords : micromixers * piv * electrochemical method Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 3.371, year: 2011

  7. Fan Stagger Angle for Dirt Rejection

    Science.gov (United States)

    Gallagher, Edward J. (Inventor); Rose, Becky E. (Inventor); Brilliant, Lisa I. (Inventor)

    2015-01-01

    A gas turbine engine includes a spool, a turbine coupled to drive the spool, a propulsor coupled to be rotated about an axis by the turbine through the spool, and a gear assembly coupled between the propulsor and the spool such that rotation of the turbine drives the propulsor at a different speed than the spool. The propulsor includes a hub and a row of propulsor blades that extend from the hub. Each of the propulsor blades has a span between a root at the hub and a tip, and a chord between a leading edge and a trailing edge. The chord forms a stagger angle alpha with the axis, and the stagger angle alpha is less than 15 deg. at a position along the propulsor blade that is within an inboard 20% of the span.

  8. Staggered broad-band reflecting multilayers.

    Science.gov (United States)

    Heavens, O S; Liddell, H M

    1966-03-01

    Considerable broadening of the reflectance band of a multilayer stack may be obtained by staggering the layer thicknesses in such a way that they form either an arithmetic or geometric progression. Results are shown for asymmetric and symmetric filters of 15, 25, and 35 layers. The presence of the narrowband transmission peaks exhibited by the symmetric filters is explained, and the advantages of the use of this type of filter as an interference filter is discussed.

  9. Lower working heights decrease contraction intensity of shoulder muscles in a herringbone 30° milking parlor.

    Science.gov (United States)

    Cockburn, Marianne; Schick, Matthias; Maffiuletti, Nicola A; Gygax, Lorenz; Savary, Pascal; Umstätter, Christina

    2017-06-01

    Musculoskeletal disorders have been a main concern in milkers for many years. To improve posture, a formula was developed in a previous study to calculate ergonomically optimal working heights for various milking parlor types. However, the working height recommendations based on the formula for the herringbone 30° parlor were broad. To clarify the recommendations for the optimal working height, we investigated the effect of working height on upper limb and shoulder muscle contraction intensities. We evaluated 60 milking cluster attachment procedures in a herringbone 30° milking parlor in 7 men and 9 women. Specifically, we examined the effect of working height on muscle contraction intensity of 4 arm and shoulder muscles bilaterally (flexor carpi ulnaris, biceps brachii, deltoideus anterior, and upper trapezius) by using surface electromyography. The working heights (low, medium, and high), which reflect the ratio of the subject's height to the height of the udder base, were used in the milking health formula to determine and fit individual depth of pits. Data were evaluated for each muscle and arm side in the functions holding and attaching. Statistical analysis was performed using linear mixed effects models, where muscle contraction intensity served as a target variable, whereas working height coefficient, sex, subject height, and repetition were treated as fixed effects, and repetition group nested in working height nested in subject was considered a random effect. Contraction intensities decreased with decreasing working height for the deltoideus anterior and upper trapezius, but not for the flexor carpi ulnaris or the biceps brachii muscles in both holding and attaching arm functions. We found that milking at a lower working height reduced muscle contraction intensities of the shoulder muscles. Women showed higher contraction intensities than men, whereas subject height had no effect. The study demonstrated that a lower working height decreased muscular

  10. Levitation and locomotion on an air-table of plates with herringbone grooves

    Science.gov (United States)

    Hinch, John; de Maleprade, Helene

    2017-11-01

    Recent experiments in ESPCI in Paris and numerical simulations in Nano- and Microfluidics in Darmstadt have shown that plates with herringbone grooves in their base are accelerated on an air-table in the direction that the chevron grooves point. A simple two-dimensional model is constructed of the air flow down a channel with pressure controlled influx across the lower boundary. Limiting cases are considered of low and high Reynolds numbers, and of small and large pressure drop down the channel compared with the pressure drop across the porous plate. The levitation and locomotion forces are calculated. A prediction is made for the locomotive acceleration which avoids the complications of the shorter grooves which exit the front and back edges.

  11. Chaotic micromixing in open wells using audio-frequency acoustic microstreaming.

    Science.gov (United States)

    Petkovic-Duran, Karolina; Manasseh, Richard; Zhu, Yonggang; Ooi, Andrew

    2009-10-01

    Mixing fluids for biochemical assays is problematic when volumes are very small (on the order of the 10 microL typical of single drops), which has inspired the development of many micromixing devices. In this paper, we show that micromixing is possible in the simple open wells of standard laboratory consumables using appropriate acoustic frequencies that can be applied using cheap, conventional audio components. Earlier work has shown that the phenomenon of acoustic microstreaming can mix fluids, provided that bubbles are introduced into a specially designed microchamber or that high-frequency surface acoustic wave devices are constructed. We demonstrate a key simplification: acoustic micromixing at audio frequencies by ensuring the system has a liquid-air interface with a small radius of curvature. The meniscus of a drop in a small well provided an appropriately small radius, and so an introduced bubble was not necessary. Microstreaming showed improvement over diffusion-based mixing by 1-2 orders of magnitude. Furthermore, significant improvements are attainable through the utilization of chaotic mixing principles, whereby alternating fluid flow patterns are created by applying, in sequence, two different acoustic frequencies to a drop of liquid in an open well.

  12. Power module assemblies with staggered coolant channels

    Science.gov (United States)

    Herron, Nicholas Hayden; Mann, Brooks S; Korich, Mark D

    2013-07-16

    A manifold is provided for supporting a power module assembly with a plurality of power modules. The manifold includes a first manifold section. The first face of the first manifold section is configured to receive the first power module, and the second face of the first manifold section defines a first cavity with a first baseplate thermally coupled to the first power module. The first face of the second manifold section is configured to receive the second power module, and the second face of the second manifold section defines a second cavity with a second baseplate thermally coupled to the second power module. The second face of the first manifold section and the second face of the second manifold section are coupled together such that the first cavity and the second cavity form a coolant channel. The first cavity is at least partially staggered with respect to second cavity.

  13. Perturbative improvement of staggered fermions using fat links

    International Nuclear Information System (INIS)

    Lee, Weonjong

    2002-01-01

    We study the possibility of improving staggered fermions using various fat links in order to reduce perturbative corrections to the gauge-invariant staggered fermion operators. We prove five theorems on SU(3) projection, triviality in renormalization, multiple SU(3) projections, uniqueness, and equivalence. As a result of these theorems, we show that, at the one-loop level, the renormalization of staggered fermion operators is identical between SU(3) projected Fat7 links and hypercubic links, as long as the action and operators are constructed by imposing the same perturbative improvement condition. In addition, we propose a new view of SU(3) projection as a tool of tadpole improvement for the staggered fermion doublers. As a conclusion, we present alternative choices of constructing fat links to improve the staggered fermion action and operators, which deserve further investigation

  14. A Versatile Technology Based on Deep Reactive Ion Etching and Anodic Bonding for the Application of Micromixers and Microfilters

    Directory of Open Access Journals (Sweden)

    Safae MERZOUK

    2014-05-01

    Full Text Available A technology for the fabrication of silicon micromixers and microfilters is presented with their applications being analyzed. The versatility of this technology is observed with the use of two different photolithographic masks where active microfluidic components have been developed. The silicon micromixers and microfilters were developed and manufactured by photolithography (PL and deep-reactive ion etching (DRIE and then bonded onto sand-blasted glass wafers by anodic bonding. The fluidic flow within the specialized microchannel was observed under an optical microscope with micromixing using two differently colored dyes and the microfiltration of poly (D, L lactic-co-glycolic acid microparticles (MP-PLGA for size-sorting and separation Finally, the microfiltering device was injected with a whole blood sample for the separation of larger leukocyte cells.

  15. Density effect on the mixing efficiency and flow modes in T-shaped micromixers

    Directory of Open Access Journals (Sweden)

    Lobasov Alexander

    2017-01-01

    Full Text Available Flow patterns and mixing of liquids with different densities in T-shaped micromixers are numerically investigated at Reynolds number range from 1 to 250. The density ratio of the mixing media varies from 1 to 2; its effect on the flow structure and the mixing is studied. The dependences of the mixing efficiency and the pressure difference in this mixer on the density ratio and the Reynolds number are obtained. It is shown that the density ratio has a considerable effect on the flow structure, especially before the transition from the symmetric to the asymmetric flow pattern.

  16. Experimental study of heat transfer and pressures drops for cans with spiral herring-bone fins; Etude experimentale du transfert de chaleur et des pertes de charges des gaines a ailettes helicoidales en chevron

    Energy Technology Data Exchange (ETDEWEB)

    Pelce, J.; Francois, S.; Houseaux, O.; Pierre, B. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    Cans fitted with herring-bone fins are used for cooling uranium in certain nuclear reactor. By herring-bone is meant a staggered arrangement of the fins which have a plane of symmetry parallel to the general direction of liquid flow. The main geometrical parameter are then: the number of fins, the number of herring-bones, the angle of inclination of the fins with respect to the can axis, the dimensions of the fins, the can diameter and the channel diameter. The research is essentially experimental. The test are of three types: full size tests, in conditions approaching those in the reactor (constant flux, CO{sub 2} under pressure); full size tests but with a constant wall temperature, much easier to set up, and intended to distinguish rapidly between the merits of the various types of can; large-scale tests with air at atmospheric pressure for studying the phenomena in more detail. For each can tried out there is a corresponding pressure drop coefficient, a mean thermal exchange coefficient Mo-bar and a minimum exchange coefficient Mo{sub min} and Mo-bar are related by the expression Mo{sub min} = Mo-bar * f{sub c} * f, where f{sub c} and f are respectively circumferential and longitudinal singularity factor determined from a statistical study of all the temperatures measured for each can. The results are presented in about thirty tables and figures the most noteworthy results being summarized in the conclusion. (authors) [French] Les gaines a ailettes en chevron sont utilisees pour le refroidissement de l'uranium dans certains reacteurs nucleaires. Par chevron, on entend une disposition alternee des ailettes ayant un plan de symetrie parallele a la direction generale de l'ecoulement fluide. Les principaux parametres geometriques sont alors: le nombre des ailettes, le nombre de chevrons, l'angle d'inclinaison des ailettes par rapport a l'axe de la gaine, les dimensions des ailettes, le diametre de la gaine et le diametre du canal. L

  17. Staggered Pairing Phenomenology for UBe_13

    Science.gov (United States)

    Martisovits, V.; Cox, D. L.

    1998-03-01

    The staggered-pairing Ginzburg-Landau phenomenology based upon Cooper pairs with a finite center-of-mass momentum was previously applied to the hexagonal heavy-fermion superconductors UPt_3,(R. Heid, Ya. B. Bazaliy, V. Martisovits, and D. L. Cox, Phys. Rev. Lett. 74), 2571 (1995). UPd_2Al_3, and UNi_2Al_3.(V. Martisovits and D. L. Cox (to be published); Report No. cond-mat/9706245.) Here we apply this phenomenology to study the cubic heavy-fermion superconductor UBe_13. We find the momentum of Cooper pairs to be at X points on the Brillouin-zone boundary and identify a three-component superconducting order parameter transforming as an X-point irreducible representation of the space group. Minimizing the free energy, we find possible superconducting phases and the upper critical field H_c2. We investigate coupling to strain fields and the possibility of magnetic order and charge-density waves induced by superconductivity. To explain multiple superconducting phases in the temperature-thorium-concentration phase diagram of U_1-xTh_xBe_13, we model the influence of thorium in terms of random tetragonal strain fields.

  18. An inverted micro-mixer based on a magnetically-actuated cilium made of Fe doped PDMS

    Science.gov (United States)

    Liu, Fengli; Zhang, Jun; Alici, Gursel; Yan, Sheng; Mutlu, Rahim; Li, Weihua; Yan, Tianhong

    2016-09-01

    In this paper, we report a new micromixer based on a flexible artificial cilium activated by an external magnetic field. The cilium is fabricated from Polydimethylsiloxane doped with Fe microparticles. The fabrication method is based on the standard sacrificial layer technology. The cilium was built on a glass slide, and then was bonded on the top of the micro-mixer chamber in a microfluidic chip. This fabrication process for the miniaturized active mixers is simple and cost effective. An electromagnetic system was used to drive the cilium and induce strong convective flows of the fluid in the chamber. In the presence of an alternating magnetic field, the cilium applied a corresponding alternating force on the surrounding fluids. The performance of the electromagnetically activated cilium was quantified and optimized in order to obtain maximum mixing performance. In addition, the mixing performance of the cilium in a circular micro-chamber was compared with pure diffusion. Up to 80% of a 60 ul liquid in the chamber can be fully mixed after 2 min using a cilium mixer under a magnetic flux density of 22 mT in contrast to the 20 min which were needed to obtain the same mixing percentage under pure diffusion. Furthermore, for a mixing degree of 80%, the mixing speed for the cilia micromixer proposed in this study was 9 times faster than that of the diffusion-based micro-mixers reported in the literature.

  19. Rapid method for design and fabrication of passive micromixers in microfluidic devices using a direct-printing process.

    Science.gov (United States)

    Liu, Ai-Lin; He, Feng-yun; Wang, Kang; Zhou, Ting; Lu, Yu; Xia, Xing-hua

    2005-09-01

    We developed a facile and rapid one-step technique for design and fabrication of passive micromixers in microfluidic devices using a direct-printing process. A laser printing mechanism was dexterously adopted to pattern the microchannels with different gray levels using vector graphic software. With the present method, periodically ordered specific bas-relief microstructures can be easily fabricated on transparencies by a simple printing process. The size and shape of the resultant microstructures are determined by the gray level of the graphic software and the resolution of the laser printer. Patterns of specific bas-relief microstructures on the floor of a channel act as obstacles in the flow path for advection mixing, which can be used as efficient mixing elements. The mixing effect of the resultant micromixer in microfluidic devices was evaluated using CCD fluorescence spectroscopy. We found that the mixing performance depends strongly on the gray level values. Under optimal conditions, fast passive mixing with our periodic ordered patterns in microfluidic devices has been achieved at the very early stages of the laminar flow. In addition, fabrication of micromixers using the present versatile technique requires less than an hour. The present method is promising for fabrication of micromixers in microfluidic devices at low cost and without complicated devices and environment, providing a simple solution to mixing problems in the micro-total-analysis-systems field.

  20. Estimation of Parameters of CCF with Staggered Testing

    International Nuclear Information System (INIS)

    Kim, Myung-Ki; Hong, Sung-Yull

    2006-01-01

    Common cause failures are extremely important in reliability analysis and would be dominant to risk contributor in a high reliable system such as a nuclear power plant. Of particular concern is common cause failure (CCF) that degrades redundancy or diversity implemented to improve a reliability of systems. Most of analyses of parameters of CCF models such as beta factor model, alpha factor model, and MGL(Multiple Greek Letters) model deal a system with a nonstaggered testing strategy. Non-staggered testing is that all components are tested at the same time (or at least the same shift) and staggered testing is that if there is a failure in the first component, all the other components are tested immediately, and if it succeeds, no more is done until the next scheduled testing time. Both of them are applied in the nuclear power plants. The strategy, however, is not explicitly described in the technical specifications, but implicitly in the periodic test procedure. For example, some redundant components particularly important to safety are being tested with staggered testing strategy. Others are being performed with non-staggered testing strategy. This paper presents the parameter estimator of CCF model such as beta factor model, MGL model, and alpha factor model with staggered testing strategy. In addition, a new CCF model, rho factor model, is proposed and its parameter is presented with staggered testing strategy

  1. Experimental and Numerical Study of the Micromix Combustion Principle Applied for Hydrogen and Hydrogen-Rich Syngas as Fuel with Increased Energy Density for Industrial Gas Turbine Applications

    OpenAIRE

    Funke, Harald H.-W.; Dickhoff, Jens; Keinz, Jan; Anis, Haj Ayed; Parente, Alessandro; Hendrick, Patrick

    2014-01-01

    The Dry Low NOx (DLN) Micromix combustion principle with increased energy density is adapted for the industrial gas turbine APU GTCP 36-300 using hydrogen and hydrogen-rich syngas with a composition of 90 %-Vol. hydrogen (H2) and 10 %-Vol. carbon-monoxide (CO). Experimental and numerical studies of several combustor geometries for hydrogen and syngas show the successful advance of the DLN Micromix combustion from pure hydrogen to hydrogen-rich syngas. The impact of the different fuel properti...

  2. Heavy-light semileptonic decays in staggered chiral perturbation theory

    Science.gov (United States)

    Aubin, C.; Bernard, C.

    2007-07-01

    We calculate the form factors for the semileptonic decays of heavy-light pseudoscalar mesons in partially quenched staggered chiral perturbation theory (SχPT), working to leading order in 1/mQ, where mQ is the heavy-quark mass. We take the light meson in the final state to be a pseudoscalar corresponding to the exact chiral symmetry of staggered quarks. The treatment assumes the validity of the standard prescription for representing the staggered “fourth-root trick” within SχPT by insertions of factors of 1/4 for each sea-quark loop. Our calculation is based on an existing partially quenched continuum chiral perturbation theory calculation with degenerate sea quarks by Bećirević, Prelovsek, and Zupan, which we generalize to the staggered (and nondegenerate) case. As a byproduct, we obtain the continuum partially quenched results with nondegenerate sea quarks. We analyze the effects of nonleading chiral terms, and find a relation among the coefficients governing the analytic valence mass dependence at this order. Our results are useful in analyzing lattice computations of form factors B→π and D→K, when the light quarks are simulated with the staggered action.

  3. The numerical modelling of mixing phenomena of nanofluids in passive micromixers

    Science.gov (United States)

    Milotin, R.; Lelea, D.

    2018-01-01

    The paper deals with the rapid mixing phenomena in micro-mixing devices with four tangential injections and converging tube, considering nanoparticles and water as the base fluid. Several parameters like Reynolds number (Re = 6 – 284) or fluid temperature are considered in order to optimize the process and obtain fundamental insight in mixing phenomena. The set of partial differential equations is considered based on conservation of momentum and species. Commercial package software Ansys-Fluent is used for solution of differential equations, based on a finite volume method. The results reveal that mixing index and mixing process is strongly dependent both on Reynolds number and heat flux. Moreover there is a certain Reynolds number when flow instabilities are generated that intensify the mixing process due to the tangential injections of the fluids.

  4. Application of a flow generated by IR laser and AC electric field in micropumping and micromixing

    International Nuclear Information System (INIS)

    Nakano, M; Mizuno, A

    2008-01-01

    In this paper, it is described that measurement of fluid flow generated by simultaneous operation of an infrared (IR) laser and AC electric field in a microfabricated channel. When an IR laser (1026 nm) was focused under an intense AC electric field, a circulating flow was generated around the laser focus. The IR laser and the electric field generate two flow patterns of the electrohydrodynamicss. When the laser focus is placed at the center of the gap between electrodes, the flow pattern is parallel to the AC electric field toward electrodes from the centre. On the other hand, when the laser focus is placed close to one of the electrodes, one directional flow is generated. First flow pattern can be used as a micromixer and the second one as a micropump. Flow velocity profiles of the two flow patterns were measured as a function of the laser power, intensity of the AC electric field and AC frequency.

  5. Visualization of diffusion mixing in a micro-mixer with flow paths fabricated by photolithography

    Science.gov (United States)

    Horiuchi, Toshiyuki; Morizane, Yuta

    2017-09-01

    Mixing processes of two liquids were investigated by visualizing the mixing when they were simultaneously injected in a micro-mixer with lithographically fabricated Y-shape flow paths, and the mixing phenomena was analyzed in detail. To visualize the mixing, flows were observed by an optical microscope, and a clearly detectable chemical reaction was utilized. As the two liquids, a transparent aqueous solution of a strong alkali and a phenolphthalein ethanol solution were used. When they were simultaneously injected in Y-shape flow paths of a micro-mixer, they flowed at first in parallel along the joined path as laminar flows. This is because the Reynolds' number became very small caused by the narrow flow-path widths of 50-100 μm. However, because two liquids were always contacted at the boundary, they were gradually mixed by diffusion, and the color of the mixed parts changed to vivid red. For this reason, it was able to measure the diffusion distance from the flow path center. Because the flow speeds were much faster than the diffusion speeds, the area colored in red did not depend on the time but depended on the distance from the joint point. It was known that the distance from the joint point corresponded to the time for mixing the liquids by the diffusion. It was clarified that the diffusion distance x was proportional to the square root of the diffusion time t or the distance from the joint point. The calculated diffusion coefficient D was (0.87-1.00)×10-9 m2/s.

  6. Low-cost fabrication and performance testing of Polydimethylsiloxane (PDMS) micromixers using an improved print-and-Peel (PAP) method

    Science.gov (United States)

    Abagon, Ma. Victoria; Buendia, Neil Daniel; Jasper Caracas, Corine; July Yap, Kristian

    2018-03-01

    The research presents different configurations of microfluidic mixers made from polydimethylsiloxane (PDMS) fabricated using an improved, low-cost print-and-peel (PAP) method. Processes, such as mixing, operated in the micro scale allow decreased equipment size-to-production capacity ratio and decreased energy consumption per unit product. In the study, saturated solutions of blue and yellow food dyes were introduced inside the channels using a LEGO® improvised microsyringe pump. Scanning Electron Microscopy (SEM) was used to determine the average depth of the fabricated micromixers which was found to be around 14 ¼m. The flows were observed and images were taken using a light microscope. The color intensities of the images were then measured using MATLAB®. From the relationship between color intensity and concentration, the mixing indices were calculated and found to be 0.9435 to 0.9941, which falls within the standard mixing index range (0.8 - 1.0) regardless of the flow rate and the configuration of the micromixer as verified through the two-way ANOVA. From the cost analysis, the cost of the device fabricated in this study is a hundred-fold less than expenses from standard fabrication procedures. Hence, the fabricated device provides an alternative for micromixers produced from expensive and conventional lithographic methods.

  7. Micro-Mixing Lean-Premix System for Ultra-Low Emission Hydrogen/Syngas Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Erlendur Steinthorsson; Brian Hollon; Adel Mansour

    2010-06-30

    The focus of this project was to develop the next generation of fuel injection technologies for environmentally friendly, hydrogen syngas combustion in gas turbine engines that satisfy DOE's objectives of reducing NOx emissions to 3 ppm. Building on Parker Hannifin's proven Macrolamination technology for liquid fuels, Parker developed a scalable high-performing multi-point injector that utilizes multiple, small mixing cups in place of a single conventional large-scale premixer. Due to the small size, fuel and air mix rapidly within the cups, providing a well-premixed fuel-air mixture at the cup exit in a short time. Detailed studies and experimentation with single-cup micro-mixing injectors were conducted to elucidate the effects of various injector design attributes and operating conditions on combustion efficiency, lean stability and emissions and strategies were developed to mitigate the impact of flashback. In the final phase of the program, a full-scale 1.3-MWth multi-cup injector was built and tested at pressures from 6.9bar (100psi) to 12.4bar (180psi) and flame temperatures up to 2000K (3150 F) using mixtures of hydrogen and natural gas as fuel with nitrogen and carbon dioxide as diluents. The injector operated without flash back on fuel mixtures ranging from 100% natural gas to 100% hydrogen and emissions were shown to be insensitive to combustor pressure. NOx emissions of 3-ppm were achieved at a flame temperature of 1750K (2690 F) when operating on a fuel mixture containing 50% hydrogen and 50% natural gas by volume with 40% nitrogen dilution and 1.5-ppm NOx was achieved at a flame temperature of 1680K (2564 F) using only 10% nitrogen dilution. NOx emissions of 3.5-ppm were demonstrated at a flame temperature of 1730K (2650 F) with only 10% carbon dioxide dilution. Finally, 3.6-ppm NOx emissions were demonstrated at a flame temperature over 1600K (2420 F) when operating on 100% hydrogen fuel with 30% carbon dioxide dilution. Superior

  8. High-rate synthesis of phosphine-stabilized undecagold nanoclusters using a multilayered micromixer

    International Nuclear Information System (INIS)

    Jin, Hyung Dae; Chang, Chih-Hung; Garrison, Anna; Tseng, T; Paul, Brian K

    2010-01-01

    Growth in the potential applications of nanomaterials has led to a focus on the development of new manufacturing approaches for these materials. In particular, an increased demand due to the unique properties of nanomaterials requires a substantial yield of high-performance materials and a simultaneous reduction in the environmental impact of these processes. In this paper, a high-rate production of phosphine-stabilized undecagold nanoclusters was achieved using a layer-up strategy which involves the use of microlamination architectures; the patterning and bonding of thin layers of material (laminae) to create a multilayered micromixer in the range of 25-250 μm thick was used to step up the production of phosphine-stabilized undecagold nanoclusters. The continuous production of highly monodispersed phosphine-stabilized undecagold nanoclusters at a rate of about 11.8 (mg s -1 ) was achieved using a microreactor with a size of 1.687 cm 3 . This result is about 500 times over conventional batch syntheses based on the production rate per reactor volume.

  9. Analysis of micromixers and biocidal coatings on water-treatment membranes to minimize biofouling.

    Energy Technology Data Exchange (ETDEWEB)

    Webb, Stephen W.; James, Darryl L. (Texas Tech University, Lubbock, TX); Hibbs, Michael R.; Jones, Howland D. T.; Hart, William Eugene; Khalsa, Siri Sahib; Altman, Susan Jeanne; Clem, Paul Gilbert; Elimelech, Menachem (Yale University, New Haven, CT); Cornelius, Christopher James; Sanchez, Andres L. (LMATA Government Services LLC, Albuquerque, NM); Noek, Rachael M.; Ho, Clifford Kuofei; Kang, Seokatae (Yale University, New Haven, CT); Sun, Amy Cha-Tien; Adout, Atar (Yale University, New Haven, CT); McGrath, Lucas K. (LMATA Government Services LLC, Albuquerque, NM); Cappelle, Malynda A.; Cook, Adam W.

    2009-12-01

    Biofouling, the unwanted growth of biofilms on a surface, of water-treatment membranes negatively impacts in desalination and water treatment. With biofouling there is a decrease in permeate production, degradation of permeate water quality, and an increase in energy expenditure due to increased cross-flow pressure needed. To date, a universal successful and cost-effect method for controlling biofouling has not been implemented. The overall goal of the work described in this report was to use high-performance computing to direct polymer, material, and biological research to create the next generation of water-treatment membranes. Both physical (micromixers - UV-curable epoxy traces printed on the surface of a water-treatment membrane that promote chaotic mixing) and chemical (quaternary ammonium groups) modifications of the membranes for the purpose of increasing resistance to biofouling were evaluated. Creation of low-cost, efficient water-treatment membranes helps assure the availability of fresh water for human use, a growing need in both the U. S. and the world.

  10. Reaction mechanisms and staggering in S+Ni collisions

    International Nuclear Information System (INIS)

    D'Agostino, M.; Bruno, M.; Gulminelli, F.; Morelli, L.; Baiocco, G.; Bardelli, L.; Barlini, S.; Cannata, F.; Casini, G.; Geraci, E.; Gramegna, F.; Kravchuk, V.L.; Marchi, T.; Moroni, A.; Ordine, A.; Raduta, Ad.R.

    2011-01-01

    The reactions 32 S+ 58 Ni and 32 S+ 64 Ni are studied at 14.5 A MeV. After a selection of the collision mechanism, we show that important even-odd effects are present in the isotopic fragment distributions when the excitation energy is small. Close to the multifragmentation threshold this staggering appears hidden by the rapid variation of the production yields with the fragment size. Once this effect is accounted for, the staggering appears to be a universal feature of fragment production, slightly enhanced when the emission source is neutron poor. A closer look at the behavior of the production yields as a function of the neutron excess N-Z, reveals that odd-even effects cannot be explained by pairing effects in the nuclear masses alone, but depend in a more complex way on the de-excitation chain.

  11. LES investigation of infinite staggered wind-turbine arrays

    International Nuclear Information System (INIS)

    Yang, Xiaolei; Sotiropoulos, Fotis

    2014-01-01

    The layouts of turbines affect the turbine wake interactions and thus the wind farm performance. The wake interactions in infinite staggered wind-turbine arrays are investigated and compared with infinite aligned turbine arrays in this paper. From the numerical results we identify three types of wake behaviours, which are significantly different from wakes in aligned wind-turbine arrays. For the first type, each turbine wake interferes with the pair of staggered downstream turbine wakes and the aligned downstream turbine. For the second type, each turbine wake interacts with the first two downstream turbine wakes but does not show significant interference with the second aligned downstream turbine. For the third type, each turbine wake recovers immediately after passing through the gap of the first two downstream turbines and has little interaction with the second downstream turbine wakes The extracted power density and power efficiency are also studied and compared with aligned wind-turbine arrays

  12. MILC staggered conjugate gradient performance on Intel KNL

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ruiz [Indiana Univ., Bloomington, IN (United States). Dept. of Physics; Detar, Carleton [Univ. of Utah, Salt Lake City, UT (United States). Dept. of Physics and Astronomy; Doerfler, Douglas W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC); Gottlieb, Steven [Indiana Univ., Bloomington, IN (United States). Dept. of Physics; Jha, Asish [Intel Corp., Hillsboro, OR (United States). Sofware and Services Group; Kalamkar, Dhiraj [Intel Labs., Bangalore (India). Parallel Computing Lab.; Toussaint, Doug [Univ. of Arizona, Tucson, AZ (United States). Physics Dept.

    2016-11-03

    We review our work done to optimize the staggered conjugate gradient (CG) algorithm in the MILC code for use with the Intel Knights Landing (KNL) architecture. KNL is the second gener- ation Intel Xeon Phi processor. It is capable of massive thread parallelism, data parallelism, and high on-board memory bandwidth and is being adopted in supercomputing centers for scientific research. The CG solver consumes the majority of time in production running, so we have spent most of our effort on it. We compare performance of an MPI+OpenMP baseline version of the MILC code with a version incorporating the QPhiX staggered CG solver, for both one-node and multi-node runs.

  13. An interpretation of staggering effects by correlation observables

    Directory of Open Access Journals (Sweden)

    Baiocco G.

    2012-07-01

    Full Text Available The reactions 32S+58,64Ni are studied at 14.5 A MeV. Evidence is found for odd-even effects in isotopic observables of the decay of a projectile-like source. The influence of secondary decays on the staggering is studied with a correlation function technique, showing that odd-even effects are due to interplay between pairing effects in the nuclear masses and in the level densities.

  14. An optimal staggered harvesting strategy for herbaceous biomass energy crops

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, M.G.; English, B.C. [Univ. of Tennessee, Knoxville, TN (United States)

    1993-12-31

    Biofuel research over the past two decades indicates lignocellulosic crops are a reliable source of feedstock for alternative energy. However, under the current technology of producing, harvesting and converting biomass crops, the cost of biofuel is not competitive with conventional biofuel. Cost of harvesting biomass feedstock is a single largest component of feedstock cost so there is a cost advantage in designing a biomass harvesting system. Traditional farmer-initiated harvesting operation causes over investment. This study develops a least-cost, time-distributed (staggered) harvesting system for example switch grass, that calls for an effective coordination between farmers, processing plant and a single third-party custom harvester. A linear programming model explicitly accounts for the trade-off between yield loss and benefit of reduced machinery overhead cost, associated with the staggered harvesting system. Total cost of producing and harvesting switch grass will decline by 17.94 percent from conventional non-staggered to proposed staggered harvesting strategy. Harvesting machinery cost alone experiences a significant reduction of 39.68 percent from moving from former to latter. The net return to farmers is estimated to increase by 160.40 percent. Per tonne and per hectare costs of feedstock production will decline by 17.94 percent and 24.78 percent, respectively. These results clearly lend support to the view that the traditional system of single period harvesting calls for over investment on agricultural machinery which escalates the feedstock cost. This social loss to the society in the form of escalated harvesting cost can be avoided if there is a proper coordination among farmers, processing plant and custom harvesters as to when and how biomass crop needs to be planted and harvested. Such an institutional arrangement benefits producers, processing plant and, in turn, end users of biofuels.

  15. Optimization of the Single Staggered Wire and Tube Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Arsana I Made

    2016-01-01

    Full Text Available Wire and tube heat exchanger consists of a coiled tube, and wire is welded on the two sides of it in normal direction of the tube. Generally,wire and tube heat exchanger uses inline wire arrangement between the two sides, whereas in this study, it used staggered wire arrangement that reduces the restriction of convection heat transfer. This study performed the optimization of single staggered wire and tube heat exchanger to increase the capacity and reduce the mass of the heat exchanger. Optimization was conducted with the Hooke-Jeeves method, which aims to optimize the geometry of the heat exchanger, especially on the diameter (dw and the distance between wires (pw. The model developed to present heat transfer correlations on single staggered wire and tube heat exchanger was valid. The maximum optimization factor obtained when the diameter wire was 0.9 mm and the distance between wires (pw was 11 mm with the fref value = 1.5837. It means that the optimized design only using mass of 59,10 % and could transfer heat about 98,5 % from the basis design.

  16. Towards an understanding of staggering effects in dissipative binary collisions

    International Nuclear Information System (INIS)

    D'Agostino, M.; Bruno, M.; Gulminelli, F.; Morelli, L.; Baiocco, G.; Bardelli, L.; Barlini, S.; Cannata, F.; Casini, G.; Geraci, E.; Gramegna, F.; Kravchuk, V.L.; Marchi, T.; Moroni, A.; Ordine, A.; Raduta, Ad.R.

    2012-01-01

    The reactions 32 S+ 58,64 Ni are studied at 14.5 A MeV. Evidence is found for important odd–even effects in isotopic observables of selected peripheral collisions corresponding to the decay of a projectile-like source. The influence of secondary decays on the staggering is studied with a correlation function technique. It is shown that this method is a powerful tool to get experimental information on the evaporation chain, in order to constrain model calculations. Specifically, we show that odd–even effects are due to interplay between pairing effects in the nuclear masses and in the level densities.

  17. Improving the quark number susceptibilities for staggered fermions

    International Nuclear Information System (INIS)

    Gavai, Rajiv V.

    2003-01-01

    Quark number susceptibilities approach their ideal gas limit at sufficiently high temperatures. As in the case of other thermodynamic quantities, this limit itself is altered substantially on lattices with small temporal extent, N t = 4-8, making it thus difficult to check the validity of perturbation theory. Unlike other observables, improving susceptibilities or number densities is subject to constraints of current conservation and absence of chemical potential (μ) dependent divergences. We construct such an improved number density and susceptibility for staggered fermions and show that they approximate the continuum ideal gas limit better on small temporal lattices

  18. XFEM Modelling of Multi-holes Plate with Single-row and Staggered Holes Configurations

    Directory of Open Access Journals (Sweden)

    Supar Khairi

    2017-01-01

    Full Text Available Joint efficiency is the key to composite structures assembly design, good structures response is dependent upon multi-holes behavior as subjected to remote loading. Current benchmarking work were following experimental testing series taken from literature on multi-holes problem. Eleven multi-hole configurations were investigated with various pitch and gage distance of staggered holes and non-staggered holes (single-row holes. Various failure modes were exhibited, most staggered holes demonstrates staggered crack path but non-staggered holes series displayed crack path along net-section plane. Stress distribution were carried out and good agreement were exhibited in experimental observation as reported in the respective literature. Consequently, strength prediction work were carried out under quasi-static loading, most showed discrepancy between 8% -31%, better prediction were exhibited in thicker and non-staggered holes plate combinations.

  19. Global phenomenological descriptions of nuclear odd-even mass staggering

    DEFF Research Database (Denmark)

    Hove, Dennis; Jensen, Aksel Stenholm; Riisager, Karsten

    2013-01-01

    We examine the general nature of nuclear odd-even mass differences by employing neutron and proton mass relations that emphasize these effects. The most recent mass tables are used. The possibility of a neutron excess dependence of the staggering is examined in detail in separate regions defined ...... into a global phenomenological expression, ready to use in a binding energy formula. The results deviate from previous parametrizations, and in particular found to be significantly superior to a recent two term, A−1 dependence.......We examine the general nature of nuclear odd-even mass differences by employing neutron and proton mass relations that emphasize these effects. The most recent mass tables are used. The possibility of a neutron excess dependence of the staggering is examined in detail in separate regions defined...... by the main nuclear shells, and a clear change in this dependency is found at Z=50 for both neutrons and protons. A further separation into odd and even neutron (proton) number produces very accurate local descriptions of the mass differences for each type of nucleons. These odd-even effects are combined...

  20. ΔI = 2 Nuclear Staggering in Superdeformed Rotational Bands

    Directory of Open Access Journals (Sweden)

    Okasha M. D.

    2014-01-01

    Full Text Available A four parameters model including collective rotational en ergies to fourth order is ap- plied to reproduce the ∆ I = 2 staggering in transition energies in four selected super deformed rotational bands, namely, 148 Gd (SD6, 194 Hg (SD1, SD2, SD3. The model parameters and the spin of the bandhead have been extracted a ssuming various val- ues to the lowest spin of the bandhead at nearest integer, in o rder to obtain a minimum root mean square deviation between calculated and the exper imental transition energies. This allows us to suggest the spin values for the energy level s which are experimentally unknown. For each band a staggering parameter represent the deviation of the transition energies from a smooth reference has been determined by calc ulating the fourth order derivative of the transition energies at a given spin. The st aggering parameter contains five consecutive transition energies which is denoted here a s the five-point formula. In order to get information about the dynamical moment of ine rtia, the two point for- mula which contains only two consecutive transition energi es has been also considered. The dynamical moment of inertia decreasing with increasing rotational frequency for A ∼ 150, while increasing for A ∼ 190 mass regions.

  1. Staggered and short-period solutions of the saturable discrete nonlinear Schrodinger equation

    DEFF Research Database (Denmark)

    Khare, A.; Rasmussen, K.O.; Samuelsen, Mogens Rugholm

    2009-01-01

    We point out that the nonlinear Schrodinger lattice with a saturable nonlinearity also admits staggered periodic aswell as localized pulse-like solutions. Further, the same model also admits solutions with a short period. We examine the stability of these solutions and find that the staggered...

  2. Lowrank seismic-wave extrapolation on a staggered grid

    KAUST Repository

    Fang, Gang

    2014-05-01

    © 2014 Society of Exploration Geophysicists. We evaluated a new spectral method and a new finite-difference (FD) method for seismic-wave extrapolation in time. Using staggered temporal and spatial grids, we derived a wave-extrapolation operator using a lowrank decomposition for a first-order system of wave equations and designed the corresponding FD scheme. The proposed methods extend previously proposed lowrank and lowrank FD wave extrapolation methods from the cases of constant density to those of variable density. Dispersion analysis demonstrated that the proposed methods have high accuracy for a wide wavenumber range and significantly reduce the numerical dispersion. The method of manufactured solutions coupled with mesh refinement was used to verify each method and to compare numerical errors. Tests on 2D synthetic examples demonstrated that the proposed method is highly accurate and stable. The proposed methods can be used for seismic modeling or reverse-time migration.

  3. Quantifying macro-mixing and micro-mixing in a static mixer using two-tracer laser-induced fluorescence

    Science.gov (United States)

    Lehwald, Andreas; Thévenin, Dominique; Zähringer, Katharina

    2010-05-01

    An experimental procedure has been developed to quantify mixing at large scales (flow-induced) and at small scales (induced by molecular diffusion). It relies on the simultaneous imaging of two different fluorescent tracers using planar laser-induced fluorescence (PLIF). In order to quantify micro-mixing, a suitable neutralization reaction involving the fluorescent tracer uranine has been identified. Using PLIF, uranine is measured simultaneously with another fluorescent tracer, pyridine 2, employed to characterize macro-mixing. Since both tracers are quite inexpensive, this procedure allows an in-depth characterization of mixing properties even in large installations, by measuring the concentration fields of the involved tracers in a non-intrusive manner. This measurement procedure has been applied to a static mixer segment with geometrical features and dimensions similar to that found in practical applications. Laminar inflow conditions are employed. The flow and mixing analysis obtained by post-processing the measurement results is detailed in the present article.

  4. Temperature-dependent thermal properties of a paraffin phase change material embedded with herringbone style graphite nanofibers

    International Nuclear Information System (INIS)

    Warzoha, Ronald J.; Weigand, Rebecca M.; Fleischer, Amy S.

    2015-01-01

    Highlights: • The thermal properties of a PCM with nanofibers are determined. • The solid-phase thermal conductivity scales exponentially with volume fraction. • The liquid-phase thermal conductivity is only enhanced beyond a critical percolation threshold. • The nanoscale interface resistance depends on the nanoparticle’s dimensionality. • The thermal diffusivity and volumetric heat capacity of the nanoenhanced PCMs are found. - Abstract: In many studies, carbon nanoparticles with high values of thermal conductivity (10–3000 W/m K) have been embedded into phase change thermal energy storage materials (PCMs) in order to enhance their bulk thermal properties. While a great deal of work to date has focused on determining the effect of these nanoparticles on a PCM’s solid phase thermal properties, little is known about their effect on its liquid phase thermal properties. Thus, in this study, the effect of implanting randomly oriented herringbone style graphite nanofibers (HGNF, average diameter = 100 nm, average length = 20 μm) on the bulk thermal properties of an organic paraffin PCM (IGI 1230A, T melt = 329.15 K) in both the solid and liquid phase is quantified. The bulk thermal conductivity, volumetric heat capacity and thermal diffusivity of HGNF/PCM nanocomposites are obtained as a function of temperature and HGNF volume loading level. It is found that the property enhancement varies significantly depending on the material phase. In order to explain the difference between solid and liquid phase thermal properties, heat flow at the nanoparticle–PCM and nanoparticle–nanoparticle interfaces is examined as a function of HGNF loading level and temperature. To do this, the solid and liquid phase thermal boundary resistances (TBRs) between the nanoparticles and the surrounding PCM and/or between contacting nanoparticles are found. Results suggest that the TBR at the HGNF–PCM interface is nearly double the TBR across the HGNF–HGNF interface in

  5. Spontaneous emission spectra from a staggered-array undulator

    International Nuclear Information System (INIS)

    Shimada, Shigeki; Okada, Kouji; Masuda, Kai; Sobajima, Masaaki; Yoshikawa, Kiyoshi; Ohnishi, Masami; Yamamoto, Yasushi; Toku, Hisayuki

    1997-01-01

    A staggered-array undulator set inside the superconducting solenoid coils is shown to be able to provide high undulator fields larger than the longitudinal magnetic fields, a small undulator period, easy tunability through the solenoid coil current, and compact and easy fabrication. The overall performance characteristics of this undulator were studied mainly with respect to iron and aluminum disk widths, and spontaneous emission spectra through the numerical calculations. The maximum undulator field is found to be obtained for the ratio of the aluminum disk width to the undulator period of 0.45. The line widths (FWHM) of the spontaneous emission spectra, however, do not show N w -1 dependence on the number of the undulator period N w for practical beams with a Gaussian distribution, compared with for a single electron. The energy spread among various parameters is seen to play an important role in reducing the FWHM with increase of N w . The large tunability of the wavelength is proved to cover 6-10 mm by changing the solenoid magnetic field from 0.4 T to 1.6 T. (author)

  6. X-ray imaging bilinear staggered GaAs detectors

    Energy Technology Data Exchange (ETDEWEB)

    Achmadullin, R.A.; Dvoryankin, V.F. E-mail: vfd217@ire216.msk.su; Dvoryankina, G.G.; Dikaev, Y.M.Yu.M.; Krikunov, A.I.; Kudryashov, A.A.; Panova, T.M.; Petrov, A.G.; Telegin, A.A

    2004-09-21

    The multichannel bilinear X-ray detector based on epitaxial GaAs structures is developed to obtain a digital X-ray image. Each detector operates in photovoltaic mode without reverse bias that enables almost complete elimination of detector noise arising due to leakage currents. The sensitivity range of the epitaxial GaAs photovoltaic X-ray detector covers the effective energies from 8 to 120 keV. A maximum response of the detector operating in the short-circuit mode was observed at an energy of 35 keV and amounted to 30 {mu}A min/(Gy cm{sup 2}). The multichannel detector was made of 1024 pixels with pitch of 0.8 mm. The spatial resolution of double staggered sensor row is twice as high as the resolution of that of single sensor row with the same pitch. Measured spatial resolution is 1.2 line-pairs/mm, contrast sensitivity not worse 1% and dynamic range defined as the ratio of maximum detectable X-ray signal to electronic noise level more than 2000 are received.

  7. X-ray imaging bilinear staggered GaAs detectors

    International Nuclear Information System (INIS)

    Achmadullin, R.A.; Dvoryankin, V.F.; Dvoryankina, G.G.; Dikaev, Y.M.Yu.M.; Krikunov, A.I.; Kudryashov, A.A.; Panova, T.M.; Petrov, A.G.; Telegin, A.A.

    2004-01-01

    The multichannel bilinear X-ray detector based on epitaxial GaAs structures is developed to obtain a digital X-ray image. Each detector operates in photovoltaic mode without reverse bias that enables almost complete elimination of detector noise arising due to leakage currents. The sensitivity range of the epitaxial GaAs photovoltaic X-ray detector covers the effective energies from 8 to 120 keV. A maximum response of the detector operating in the short-circuit mode was observed at an energy of 35 keV and amounted to 30 μA min/(Gy cm 2 ). The multichannel detector was made of 1024 pixels with pitch of 0.8 mm. The spatial resolution of double staggered sensor row is twice as high as the resolution of that of single sensor row with the same pitch. Measured spatial resolution is 1.2 line-pairs/mm, contrast sensitivity not worse 1% and dynamic range defined as the ratio of maximum detectable X-ray signal to electronic noise level more than 2000 are received

  8. High temperature QCD with three flavors of improved staggered quarks

    International Nuclear Information System (INIS)

    Bernard, C.; Burch, T.; Tar, C.E. de; Gottlieb, Steven; Gregory, Eric; Heller, U.M.; Osborn, J.; Sugar, R.L.; Toussaint, D.

    2003-01-01

    We present an update of our study of high temperature QCD with three flavors of quarks, using a Symanzik improved gauge action and the Asqtad staggered quark action. Simulations are being carried out on lattices with N t = 4, 6 and 8 for the case of three degenerate quarks with masses less than or equal to the strange quark mass, m s and on lattices with N t = 6 and 8 for degenerate up and down quarks with masses in the range 0.2m s ≤ m u,d ≤ 0.6m s and the strange quark fixed near its physical value. We also report on first computations of quark number susceptibilities with the Asqtad action. These susceptibilities are of interest because they can be related to event-by-event fluctuations in heavy ion collision experiments. Use of the improved quark action leads to a substantial reduction in lattice artifacts. This can be seen already for free fermions and carries over into our results for QCD

  9. Systematics of the K suppi = 2+ gamma vibrational bands and odd-even staggering

    CERN Document Server

    Gupta, J B

    2003-01-01

    The structure of the K suppi = 2+ gamma vibrational bands and the quasi-gamma bands of even-Z-even-N nuclei is investigated on a global scale, vis-a-vis the variation of band head, the moment of inertia of the band and the odd-even spin staggering. The variation with N and Z and with spin J of the odd-even spin energy staggering index is studied and a unified view of the same is presented. (author)

  10. Two-color lattice QCD with staggered quarks

    Energy Technology Data Exchange (ETDEWEB)

    Scheffler, David

    2015-07-20

    The study of quantum chromodynamics (QCD) at finite temperature and density provides important contributions to the understanding of strong-interaction matter as it is present e.g. in nuclear matter and in neutron stars or as produced in heavy-ion collision experiments. Lattice QCD is a non-perturbative approach, where equations of motion for quarks and gluons are discretized on a finite space-time lattice. The method successfully describes the behavior of QCD in the vacuum and at finite temperature, however it cannot be applied to finite baryon density due to the fermion sign problem. Various QCD-like theories, that offer to draw conclusions about QCD, allow simulations also at finite densities. In this work we investigate two-color QCD as a popular example of a QCD-like theory free from the sign problem with methods from lattice gauge theory. For the generation of gauge configurations with two dynamical quark flavors in the staggered formalism with the ''rooting trick'' we apply the Rational Hybrid Monte Carlo (RHMC) algorithm. We carry out essential preparatory work for future simulations at finite density. As a start, we concentrate on the calculation of the effective potential for the Polyakov loop, which is an order parameter for the confinement-deconfinement transition, in dependence of the temperature and quark mass. It serves as an important input for effective models of QCD. We obtain the effective potential via the histogram method from local distributions of the Polyakov loop. To study the influence of dynamical quarks on gluonic observables, the simulations are performed with large quark masses and are compared to calculations in the pure gauge theory. In the second part of the thesis we examine aspects of the chiral phase transition along the temperature axis. The symmetry group of chiral symmetry in two-color QCD is enlarged to SU(2N{sub f}). Discretized two-color QCD in the staggered formalism exhibits a chiral symmetry breaking

  11. The Nucleon Axial Form Factor and Staggered Lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Aaron Scott [Chicago U.

    2017-01-01

    The study of neutrino oscillation physics is a major research goal of the worldwide particle physics program over the upcoming decade. Many new experiments are being built to study the properties of neutrinos and to answer questions about the phenomenon of neutrino oscillation. These experiments need precise theoretical cross sections in order to access fundamental neutrino properties. Neutrino oscillation experiments often use large atomic nuclei as scattering targets, which are challenging for theorists to model. Nuclear models rely on free-nucleon amplitudes as inputs. These amplitudes are constrained by scattering experiments with large nuclear targets that rely on the very same nuclear models. The work in this dissertation is the rst step of a new initiative to isolate and compute elementary amplitudes with theoretical calculations to support the neutrino oscillation experimental program. Here, the eort focuses on computing the axial form factor, which is the largest contributor of systematic error in the primary signal measurement process for neutrino oscillation studies, quasielastic scattering. Two approaches are taken. First, neutrino scattering data on a deuterium target are reanalyzed with a model-independent parametrization of the axial form factor to quantify the present uncertainty in the free-nucleon amplitudes. The uncertainties on the free-nucleon cross section are found to be underestimated by about an order of magnitude compared to the ubiquitous dipole model parametrization. The second approach uses lattice QCD to perform a rst-principles computation of the nucleon axial form factor. The Highly Improved Staggered Quark (HISQ) action is employed for both valence and sea quarks. The results presented in this dissertation are computed at physical pion mass for one lattice spacing. This work presents a computation of the axial form factor at zero momentum transfer, and forms the basis for a computation of the axial form factor momentum dependence

  12. A rapid three-dimensional vortex micromixer utilizing self-rotation effects under low Reynolds number conditions

    CERN Document Server

    Che Hsin, Lin; Lung Ming, Fu; 10.1088/0960-1317/15/5/006

    2005-01-01

    This paper proposes a novel three-dimensional (3D) vortex micromixer for micro-total-analysis-systems ( mu TAS) applications which utilizes self-rotation effects to mix fluids in a circular chamber at low Reynolds numbers (Re). The microfluidic mixer is fabricated in a three-layer glass structure for delivering fluid samples in parallel. The fluids are driven into the circular mixing chamber by means of hydrodynamic pumps from two fluid inlet ports. The two inlet channels divide into eight individual channels tangent to a 3D circular chamber for the purpose of mixing. Numerical simulation of the microfluidic dynamics is employed to predict the self-rotation phenomenon and to estimate the mixing performance under various Reynolds number conditions. Experimental flow visualization by mixing dye samples is performed in order to verify the numerical simulation results. A good agreement is found to exist between the two sets of results. The numerical results indicate that the mixing performance can be as high as 9...

  13. Numerical properties of staggered quarks with a taste-dependent mass term

    CERN Document Server

    de Forcrand, Philippe; Panero, Marco

    2012-01-01

    The numerical properties of staggered Dirac operators with a taste-dependent mass term proposed by Adams [1,2] and by Hoelbling [3] are compared with those of ordinary staggered and Wilson Dirac operators. In the free limit and on (quenched) interacting configurations, we consider their topological properties, their spectrum, and the resulting pion mass. Although we also consider the spectral structure, topological properties, locality, and computational cost of an overlap operator with a staggered kernel, we call attention to the possibility of using the Adams and Hoelbling operators without the overlap construction. In particular, the Hoelbling operator could be used to simulate two degenerate flavors without additive mass renormalization, and thus without fine-tuning in the chiral limit.

  14. Gap states and edge properties of rectangular graphene quantum dot in staggered potential

    Science.gov (United States)

    Jeong, Y. H.; Eric Yang, S.-R.

    2017-09-01

    We investigate edge properties of a gapful rectangular graphene quantum dot in a staggered potential. In such a system gap states with discrete and closely spaced energy levels exist that are spatially located on the left or right zigzag edge. We find that, although the bulk states outside the energy gap are nearly unaffected, spin degeneracy of each gap state is lifted by the staggered potential. We have computed the occupation numbers of spin-up and -down gap states at various values of the strength of the staggered potential. The electronic and magnetic properties of the zigzag edges depend sensitively on these numbers. We discuss the possibility of applying this system as a single electron spintronic device.

  15. Single-molecule observation of helix staggering, sliding, and coiled coil misfolding

    Science.gov (United States)

    Xi, Zhiqun; Gao, Ying; Sirinakis, George; Guo, Honglian; Zhang, Yongli

    2012-01-01

    The biological functions of coiled coils generally depend on efficient folding and perfect pairing of their α-helices. Dynamic changes in the helical registry that lead to staggered helices have only been proposed for a few special systems and not found in generic coiled coils. Here, we report our observations of multiple staggered helical structures of two canonical coiled coils. The partially folded structures are formed predominantly by coiled coil misfolding and occasionally by helix sliding. Using high-resolution optical tweezers, we characterized their energies and transition kinetics at a single-molecule level. The staggered states occur less than 2% of the time and about 0.1% of the time at zero force. We conclude that dynamic changes in helical registry may be a general property of coiled coils. Our findings should have broad and unique implications in functions and dysfunctions of proteins containing coiled coils. PMID:22451899

  16. Ergovaline does not alter the severity of ryegrass staggers induced by lolitrem B.

    Science.gov (United States)

    Finch, S C; Vlaming, J B; Sutherland, B L; van Koten, C; Mace, W J; Fletcher, L R

    2018-03-01

    To investigate a possible interaction between lolitrem B and ergovaline by comparing the incidence and severity of ryegrass staggers in sheep grazing ryegrass (Lolium perenne) containing lolitrem B or ryegrass containing both lolitrem B and ergovaline. Ninety lambs, aged approximately 6 months, were grazed on plots of perennial ryegrass infected with either AR98 endophyte (containing lolitrem B), standard endophyte (containing lolitrem B and ergovaline) or no endophyte, for up to 42 days from 2 February 2010. Ten lambs were grazed on three replicate plots per cultivar. Herbage samples were collected for alkaloid analysis and lambs were scored for ryegrass staggers (scores from 0-5) weekly during the study. Any animal which was scored ≥4 was removed from the study. Concentrations of lolitrem B did not differ between AR98 and standard endophyte-infected pastures during the study period (p=0.26), and ergovaline was present only in standard endophyte pastures. Ryegrass staggers was observed in sheep grazing both the AR98 and standard endophyte plots, with median scores increasing in the third week of the study. Prior to the end of the 42-day grazing period, 22 and 17 animals were removed from the standard endophyte and AR98 plots, respectively, because their staggers scores were ≥4. The cumulative probability of lambs having scores ≥4 did not differ between animals grazing the two pasture types (p=0.41). There was no evidence for ergovaline increasing the severity of ryegrass staggers induced by lolitrem B. In situations where the severity of ryegrass staggers appears to be greater than that predicted on the basis of concentrations of lolitrem B, the presence of other tremorgenic alkaloids should be investigated.

  17. Horizontally staggered lightguide solar concentrator with lateral displacement tracking for high concentration applications.

    Science.gov (United States)

    Ma, Hongcai; Wu, Lin

    2015-07-10

    We present the design of a horizontally staggered lightguide solar concentrator with lateral displacement tracking for high concentration applications. This solar concentrator consists of an array of telecentric primary concentrators, a horizontally staggered lightguide layer, and a vertically tapered lightguide layer. The primary concentrator is realized by two plano-aspheric lenses with lateral movement and maintains a high F-number over an angle range of ±23.5°. The results of the simulations show that the solar concentrator achieves a high concentration ratio of 500× with ±0.5° of acceptance angle by a single-axis tracker and dual lateral translation stages.

  18. Cu-PDC-bpa solid coordination frameworks (PDC=2,5-pyrindinedicarboxylate; bpa=1,2-DI(4-pyridil)ethane)): 2D and 3D structural flexibility producing a 3-c herringbone array next to ideal

    Energy Technology Data Exchange (ETDEWEB)

    Llano-Tomé, Francisco, E-mail: francisco.llano@ehu.eus [Departamento de Mineralogía y Petrología, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU), Apdo 644, 48080 Bilbao (Spain); Bazán, Begoña, E-mail: bego.bazan@ehu.eus [Departamento de Mineralogía y Petrología, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU), Apdo 644, 48080 Bilbao (Spain); BCMaterials Parque Tecnológico de Zamudio, Ibaizabal Bidea, Edificio 500–Planta 1, 48160 Derio (Spain); Urtiaga, Miren-Karmele, E-mail: karmele.urtiaga@ehu.eus [Departamento de Mineralogía y Petrología, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU), Apdo 644, 48080 Bilbao (Spain); Barandika, Gotzone, E-mail: gotzone.barandika@ehu.eus [Departamento de Química Inorgánica, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU), Apdo 644, 48080 Bilbao (Spain); Antonia Señarís-Rodríguez, M., E-mail: tonasr@udc.es [QUIMOLMAT, Centro de Investigaciones Científicas Avanzadas (CICA) and Departamento de Química Fundamental, Facultad de Ciencias, Universidad de A Coruña, 15071A Coruña (Spain); and others

    2015-10-15

    Combination of polycarboxylate anions and dipyridyl ligands is an effective strategy to produce solid coordination frameworks (SCF) which are crystalline materials based on connections between metal ions through organic ligands. In this context, this work is focused on two novel Cu{sup II}-based SCFs exhibiting PDC (2,5-pyridinedicarboxylate) and bpa (1,2-di(4-pyridyl)ethane), being the first structures reported in literature containing both ligands. Chemical formula are [Cu{sub 2}[(PDC){sub 2}(bpa)(H{sub 2}O){sub 2}]·3H{sub 2}O·DMF (1), and [Cu{sub 2}(PDC){sub 2}(bpa)(H{sub 2}O){sub 2}]·7H{sub 2}O (2), where DMF is dimethylformamide. Compounds 1 and 2 have been characterized by means of X-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimetric (TG) analysis, differential thermal analysis (DTA) and dielectric measurements. The crystallographic analysis revealed that compounds 1 and 2 can be described as herringbone-type layers formed by helicoidal Cu-PDC-Cu chains connected through bpa ligands. Solvent molecules are crystallized between the layers, providing the inter-layer connections through hydrogen bonds. Differences between both compounds are attributable to the flexibility of bpa (in 2D) as well as to the 3D packing of the layers which is solvent dependent. This fact results in the fact that compound 2 is the most regular 3-c herringbone array reported so far. The structural dynamism of these networks is responsible for the crystalline to-amorphous to-crystalline (CAC) transformation from compound 1 to compound 2. Crystallochemical features for both compounds have also been studied and compared to similar 3-connected herringbone-arrays. - Graphical abstract: Cu-PDC-bpa 3-c herringbone arrays. - Highlights: • The most ideal herringbone array reported so far is a Cu-PDC-bpa SCF. • Conformational freedom of bpa results in 2D and 3D flexibility of the SCFs. • The flexibility of the SCFs is related to a phase transformation. • Dielectric

  19. Experimental set-up for time resolved small angle X-ray scattering studies of nanoparticles formation using a free-jet micromixer

    Energy Technology Data Exchange (ETDEWEB)

    Marmiroli, Benedetta [Institute for Biophysics and Nanosystem Research, Austrian Academy of Science, Schmiedlstrasse 6, Graz (Austria); Grenci, Gianluca [TASC INFM/CNR, SS 14 km 163.5, Basovizza, TS (Italy); Cacho-Nerin, Fernando; Sartori, Barbara; Laggner, Peter [Institute for Biophysics and Nanosystem Research, Austrian Academy of Science, Schmiedlstrasse 6, Graz (Austria); Businaro, Luca [TASC INFM/CNR, SS 14 km 163.5, Basovizza, TS (Italy); Amenitsch, Heinz, E-mail: heinz.amenitsch@elettra.trieste.i [Institute for Biophysics and Nanosystem Research, Austrian Academy of Science, Schmiedlstrasse 6, Graz (Austria)

    2010-02-15

    Recently, we have designed, fabricated and tested a free-jet micromixer for time resolved small angle X-ray scattering (SAXS) studies of nanoparticles formation in the <100 mus time range. The microjet has a diameter of 25 mum and a time of first accessible measurement of 75 mus has been obtained. This result can still be improved. In this communication, we present a method to estimate whether a given chemical or biological reaction can be investigated with the micromixer, and to optimize the beam size for the measurement at the chosen SAXS beamline. Moreover, we describe a system based on stereoscopic imaging which allows the alignment of the jet with the X-ray beam with a precision of 20 mum. The proposed experimental procedures have been successfully employed to observe the formation of calcium carbonate (CaCO{sub 3}) nanoparticles from the reaction of sodium carbonate (Na{sub 2}CO{sub 3}) and calcium chloride (CaCl{sub 2}). The induction time has been estimated in the order of 200 mus and the determined radius of the particles is about 14 nm.

  20. A superlinearly convergent finite volume method for the incompressible Navier-Stokes equations on staggered unstructured grids

    International Nuclear Information System (INIS)

    Vidovic, D.; Segal, A.; Wesseling, P.

    2004-01-01

    A method for linear reconstruction of staggered vector fields with special treatment of the divergence is presented. An upwind-biased finite volume scheme for solving the unsteady incompressible Navier-Stokes equations on staggered unstructured triangular grids that uses this reconstruction is described. The scheme is applied to three benchmark problems and is found to be superlinearly convergent in space

  1. Weakly coupled S=1/2 quantum Heisenberg antiferromagnetic chains in an effective staggered field

    International Nuclear Information System (INIS)

    Sato, Masahiro; Oshikawa, Masaki

    2002-01-01

    We study weakly coupled S=1/2 quantum Heisenberg antiferromagnetic chains in an effective staggered field. Applying mean-field (MF) theory, spin-wave theory and chain MF (CMF) theory, we can see analytically some effects of the staggered field in this higher dimensional spin system. In particular, when the staggered field and the inter-chain inter-action compete with each other, we conjecture from the MF theory that a nontrivial phase is present. The spin wave theory predicts that the behavior of the gaps induced by a staggered field is different between the competitive case and the non-competitive case. When the inter-chain interactions are weak enough, we can improve the MF phase diagram by using CMF theory and the analytical results of field theories. The ordered phase region predicted by the CMF theory is fairly smaller than one of the MF theory. Cu-benzoate, CuCl 2 · 2DMSO (dimethylsulphoxide), BaCu 2 (Si 1-x Ge x ) 2 O 7 , etc., could be described by our model in enough low temperature. (author)

  2. Kinetics of full scrum and staggered scrum engagement in under 19 ...

    African Journals Online (AJOL)

    Two hundred and eight male Rugby Union players from 13 high schools, whose ages ranged from 16 to 19 years, were used to examine the kinetics of the full scrum versus staggered scrum engagement techniques. Telemetric pressure transducers were used to measure the engagement and sustained forces acting on the ...

  3. Enhancement of Radiative Efficiency with Staggered InGaN Quantum Well Light Emitting Diodes

    Energy Technology Data Exchange (ETDEWEB)

    Tansu, Nelson; Dierolf, Volkmar; Huang, Gensheng; Penn, Samson; Zhao, Hongping; Liu, Guangyu; Li, Xiaohang; Poplawsky, Jonathan

    2011-07-14

    The technology on the large overlap InGaN QWs developed in this program is currently implemented in commercial technology in enhancing the internal quantum efficiency in major LED industry in US and Asia. The scientific finding from this work supported by the DOE enabled the implementation of this step-like staggered quantum well in the commercial LEDs.

  4. The use of staggered scheme and an absorbing buffer zone for computational aeroacoustics

    Science.gov (United States)

    Nark, Douglas M.

    1995-01-01

    Various problems from those proposed for the Computational Aeroacoustics (CAA) workshop were studied using second and fourth order staggered spatial discretizations in conjunction with fourth order Runge-Kutta time integration. In addition, an absorbing buffer zone was used at the outflow boundaries. Promising results were obtained and provide a basis for application of these techniques to a wider variety of problems.

  5. Experimental study of induced staggered magnetic fields in dysprosium gallium garnet (DGG)

    International Nuclear Information System (INIS)

    Steiner, M.; Corliss, L.M.; Hastings, J.M.; Blume, M.; Giordano, N.; Wolf, W.P.

    1979-01-01

    Neutron diffraction techniques have been used to study induced staggered magnetic field effects in DGG. The application of a uniform magnetic field at temperatures much greater than the Neel temperature induces a significant amount of antiferromagnetic order. The temperature and field dependences of this effect are in good agreement with recent theoretical predicions

  6. Partial dynamical symmetry and odd-even staggering in deformed nuclei

    Directory of Open Access Journals (Sweden)

    Leviatan A.

    2015-01-01

    Full Text Available Partial dynamical symmetry (PDS is shown to be relevant for describing the odd-even staggering in the γ-band of 156Gd while retaining solvability and good SU(3 symmetry for the ground and β bands. Several classes of interacting boson model Hamiltonians with SU(3 PDS are surveyed.

  7. Remarks on the determination of the odd--even staggering parameter in the spectrum of cadmium

    International Nuclear Information System (INIS)

    Gerstenkorn, S.; Stroke, H.H.

    1976-01-01

    From an analysis of the isotope shifts in the Cd 3261, 4678, and 4416 A lines, it is pointed out that a precise determination of the odd--even staggering parameter is limited less by experimental error than by the lack of reliable knowledge of the specific mass effect

  8. A study of manufacturing tubes with nano/ultrafine grain structure by stagger spinning

    International Nuclear Information System (INIS)

    Xia, Qinxiang; Xiao, Gangfeng; Long, Hui; Cheng, Xiuquan; Yang, Baojian

    2014-01-01

    Highlights: • Proposing a method of manufacturing tubes with nano/ultrafine crystal. • Obtaining the refined ferritic grains with an size of 500 nm after stagger spinning. • Obtaining the equiaxial ferritic grains with an size of 600 nm after annealing. - Abstract: A new method of manufacturing tubes with nano/ultrafine grain structure by stagger spinning and recrystallization annealing is proposed in this study. Two methods of the stagger spinning process are developed, the corresponding macroforming quality, microstructural evolution and mechanical properties of the spun tubes made of ASTM 1020 steel are analysed. The results reveal that a good surface smoothness and an improved spin-formability of spun parts can be obtained by the process combining of 3-pass spinning followed by a 580 °C × 0.5 h static recrystallization and 2-pass spinning with a 580 °C × 1 h static recrystallization annealing under the severe thinning ratio of wall thickness reduction. The ferritic grains with an average initial size of 50 μm are refined to 500 nm after stagger spinning under the 87% thinning ratio of wall thickness reduction. The equiaxial ferritic grains with an average size of 600 nm are generated through re-nucleation and grain growth by subsequent recrystallization annealing at 580 °C for 1 h heat preservation. The tensile strength of spun tubes has been founded to be proportional to the reciprocal of layer spacing of pearlite (LSP), and the elongation is inversely proportional to the reciprocal of LSP. This study shows that the developed method of stagger power spinning has the potential to be used to manufacture bulk metal components with nano/ultrafine grain structure

  9. Radial and staggered treatment patterns to correct hyperopia using noncontact holmium:YAG laser thermal keratoplasty.

    Science.gov (United States)

    Vinciguerra, P; Kohnen, T; Azzolini, M; Radice, P; Epstein, D; Koch, D D

    1998-01-01

    To compare the effects of two treatment patterns in the correction of hyperopia by noncontact holmium:YAG laser thermal keratoplasty (LTK). Divisione Oculistica, Ospedale S. Gerardo, Monza, Italy. Using two treatment patterns, we performed noncontact LTK in one session in 16 eyes of 8 patients with isometropic hyperopic refractive errors; mean preoperative subjective cycloplegic refraction was +4.90 diopters (D) +/- 1.17 (SD). The treatment consisted of 24 spots in three concentric rings of eight spots each; ring diameters were 6.0, 7.0, and 8.0 mm, respectively. Each spot received seven pulses of laser energy at 30 mJ/pulse. We treated one eye of each patient with a radial pattern (the spots of the three rings aligned on the eight semimeridians) and the fellow eye with a staggered pattern (the spots of the contiguous rings at 22.5 degrees from each other). Follow-up at 1, 15, 30, 90, 180, and 360 days included subjective cycloplegic refraction, uncorrected (UCVA) and spectacle-corrected visual acuity (SCVA), computerized videokeratography (CVK), and Scheimpflug camera examination. One year postoperatively, the mean subjective cycloplegic refraction was +2.75 +/- 1.6 D in the eyes treated with the radial pattern and +3.40 +/- 1.6 D in those treated with the staggered pattern; the mean change in subjective cycloplegic refraction was 2.15 and 1.50 D, respectively. Mean UCVA improved by five lines in the radial group and by four lines in the staggered group. Mean SCVA returned to preoperative levels by day 15 in the radial group and at 1 year in the staggered group; at 1 year, SCVA improved by one line in the radial group and remained unchanged in the staggered group. No eye lost one or more lines of SCVA. Refractive astigmatism was essentially unchanged in both groups. Scheimpflug photography and CVK indicated larger and more uniform corrected zones in the radial group. Radial and staggered patterns effectively corrected low hyperopia, although both were subject to a

  10. Modeling seismic wave propagation using staggered-grid mimetic finite differences

    Directory of Open Access Journals (Sweden)

    Freysimar Solano-Feo

    2017-04-01

    Full Text Available Mimetic finite difference (MFD approximations of continuous gradient and divergence operators satisfy a discrete version of the Gauss-Divergence theorem on staggered grids. On the mimetic approximation of this integral conservation principle, an unique boundary flux operator is introduced that also intervenes on the discretization of a given boundary value problem (BVP. In this work, we present a second-order MFD scheme for seismic wave propagation on staggered grids that discretized free surface and absorbing boundary conditions (ABC with same accuracy order. This scheme is time explicit after coupling a central three-level finite difference (FD stencil for numerical integration. Here, we briefly discuss the convergence properties of this scheme and show its higher accuracy on a challenging test when compared to a traditional FD method. Preliminary applications to 2-D seismic scenarios are also presented and show the potential of the mimetic finite difference method.

  11. Skew information in the XY model with staggered Dzyaloshinskii-Moriya interaction

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Liang, E-mail: lqiu@cumt.edu.cn [School of Physics, China University of Mining and Technology, Xuzhou, Jiangsu 221116 (China); Quan, Dongxiao [State Key Laboratory of Integrated Services Networks, Xidian University, Xi' an, Shaanxi 710071 (China); Pan, Fei; Liu, Zhi [School of Physics, China University of Mining and Technology, Xuzhou, Jiangsu 221116 (China)

    2017-06-01

    We study the performance of the lower bound of skew information in the vicinity of transition point for the anisotropic spin-1/2 XY chain with staggered Dzyaloshinskii-Moriya interaction by use of quantum renormalization-group method. For a fixed value of the Dzyaloshinskii-Moriya interaction, there are two saturated values for the lower bound of skew information corresponding to the spin-fluid and Néel phases, respectively. The scaling exponent of the lower bound of skew information closely relates to the correlation length of the model and the Dzyaloshinskii-Moriya interaction shifts the factorization point. Our results show that the lower bound of skew information can be a good candidate to detect the critical point of XY spin chain with staggered Dzyaloshinskii-Moriya interaction.

  12. Investigation of writing error in staggered heated-dot magnetic recording systems

    Science.gov (United States)

    Tipcharoen, W.; Warisarn, C.; Tongsomporn, D.; Karns, D.; Kovintavewat, P.

    2017-05-01

    To achieve an ultra-high storage capacity, heated-dot magnetic recording (HDMR) has been proposed, which heats a bit-patterned medium before recording data. Generally, an error during the HDMR writing process comes from several sources; however, we only investigate the effects of staggered island arrangement, island size fluctuation caused by imperfect fabrication, and main pole position fluctuation. Simulation results demonstrate that a writing error can be minimized by using a staggered array (hexagonal lattice) instead of a square array. Under the effect of main pole position fluctuation, the writing error is higher than the system without main pole position fluctuation. Finally, we found that the error percentage can drop below 10% when the island size is 8.5 nm and the standard deviation of the island size is 1 nm in the absence of main pole jitter.

  13. Development of a Front Tracking Method for Two-Phase Micromixing of Incompressible Viscous Fluids with Interfacial Tension in Solvent Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yijie [ORNL; Lim, Hyun-Kyung [ORNL; de Almeida, Valmor F [ORNL; Navamita, Ray [State University of New York, Stony Brook; Wang, Shuqiang [State University of New York, Stony Brook; Glimm, James G [ORNL; Li, Xiao-lin [State University of New York, Stony Brook; Jiao, Xiangmin [ORNL

    2012-06-01

    This progress report describes the development of a front tracking method for the solution of the governing equations of motion for two-phase micromixing of incompressible, viscous, liquid-liquid solvent extraction processes. The ability to compute the detailed local interfacial structure of the mixture allows characterization of the statistical properties of the two-phase mixture in terms of droplets, filaments, and other structures which emerge as a dispersed phase embedded into a continuous phase. Such a statistical picture provides the information needed for building a consistent coarsened model applicable to the entire mixing device. Coarsening is an undertaking for a future mathematical development and is outside the scope of the present work. We present here a method for accurate simulation of the micromixing dynamics of an aqueous and an organic phase exposed to intense centrifugal force and shearing stress. The onset of mixing is the result of the combination of the classical Rayleigh- Taylor and Kelvin-Helmholtz instabilities. A mixing environment that emulates a sector of the annular mixing zone of a centrifugal contactor is used for the mathematical domain. The domain is small enough to allow for resolution of the individual interfacial structures and large enough to allow for an analysis of their statistical distribution of sizes and shapes. A set of accurate algorithms for this application requires an advanced front tracking approach constrained by the incompressibility condition. This research is aimed at designing and implementing these algorithms. We demonstrate verification and convergence results for one-phase and unmixed, two-phase flows. In addition we report on preliminary results for mixed, two-phase flow for realistic operating flow parameters.

  14. On the spectrum of the staggered Dirac operator at finite chemical potential

    International Nuclear Information System (INIS)

    Vink, J.C.; Nationaal Inst. voor Kernfysica en Hoge-Energiefysica

    1988-12-01

    The spectrum of the staggered Dirac operator in two-dimensional QEDF is investigated at finite chemical potential. In the quenced model, it is shown that lattice artefacts cause a spurious scattering of eigenvalues. This scattering disappears when lattice distance is taken to zero. In the unquenced model, a new approach is used to show that similar effects are absent. (author). 17 refs.; 6 figs

  15. Diffraction of love waves by two staggered perfectly weak half-planes

    International Nuclear Information System (INIS)

    Asghar, S.; Zaman, F.D.; Sajida Asghar

    1989-01-01

    Love wave travelling in a layer of uniform thickness overlying a half-space is assumed to be incident on two parallel but staggered perfectly weak half-planes lying in the upper layer. The diffracted fields is calculated using the modified Wiener-Hopf technique and contour integration method. The diffracted waves satisfy the dispersion relations appropriate to different regions formed by the perfectly weak half-planes

  16. Bottleneck congestion and distribution of work start times: The economics of staggered work hours revisited

    OpenAIRE

    Takayama, Yuki

    2014-01-01

    Since the seminal work of Henderson (1981), a number of studies examined the effect of staggered work hours by analyzing models of work start time choice that consider the trade-off between negative congestion externalities and positive production externalities. However, these studies described traffic congestion using flow congestion models. This study develops a model of work start time choice with bottleneck congestion and discloses the intrinsic properties of the model. To this end, this ...

  17. New 2D adaptive mesh refinement algorithm based on conservative finite-differences with staggered grid

    Science.gov (United States)

    Gerya, T.; Duretz, T.; May, D. A.

    2012-04-01

    We present new 2D adaptive mesh refinement (AMR) algorithm based on stress-conservative finite-differences formulated for non-uniform rectangular staggered grid. The refinement approach is based on a repetitive cell splitting organized via a quad-tree construction (every parent cell is split into 4 daughter cells of equal size). Irrespective of the level of resolution every cell has 5 staggered nodes (2 horizontal velocities, 2 vertical velocities and 1 pressure) for which respective governing equations, boundary conditions and interpolation equations are formulated. The connectivity of the grid is achieved via cross-indexing of grid cells and basic nodal points located in their corners: four corner nodes are indexed for every cell and up to 4 surrounding cells are indexed for every node. The accuracy of the approach depends critically on the formulation of the stencil used at the "hanging" velocity nodes located at the boundaries between different levels of resolution. Most accurate results are obtained for the scheme based on the volume flux balance across the resolution boundary combined with stress-based interpolation of velocity orthogonal to the boundary. We tested this new approach with a number of 2D variable viscosity analytical solutions. Our tests demonstrate that the adaptive staggered grid formulation has convergence properties similar to those obtained in case of a standard, non-adaptive staggered grid formulation. This convergence is also achieved when resolution boundary crosses sharp viscosity contrast interfaces. The convergence rates measured are found to be insensitive to scenarios when the transition in grid resolution crosses sharp viscosity contrast interfaces. We compared various grid refinement strategies based on distribution of different field variables such as viscosity, density and velocity. According to these tests the refinement allows for significant (0.5-1 order of magnitude) increase in the computational accuracy at the same

  18. Entropy Stable Staggered Grid Spectral Collocation for the Burgers' and Compressible Navier-Stokes Equations

    Science.gov (United States)

    Carpenter, Mark H.; Parsani, Matteo; Fisher, Travis C.; Nielsen, Eric J.

    2015-01-01

    Staggered grid, entropy stable discontinuous spectral collocation operators of any order are developed for Burgers' and the compressible Navier-Stokes equations on unstructured hexahedral elements. This generalization of previous entropy stable spectral collocation work [1, 2], extends the applicable set of points from tensor product, Legendre-Gauss-Lobatto (LGL) to a combination of tensor product Legendre-Gauss (LG) and LGL points. The new semi-discrete operators discretely conserve mass, momentum, energy and satisfy a mathematical entropy inequality for both Burgers' and the compressible Navier-Stokes equations in three spatial dimensions. They are valid for smooth as well as discontinuous flows. The staggered LG and conventional LGL point formulations are compared on several challenging test problems. The staggered LG operators are significantly more accurate, although more costly to implement. The LG and LGL operators exhibit similar robustness, as is demonstrated using test problems known to be problematic for operators that lack a nonlinearly stability proof for the compressible Navier-Stokes equations (e.g., discontinuous Galerkin, spectral difference, or flux reconstruction operators).

  19. Re: Penetration Behavior of Opposed Rows of Staggered Secondary Air Jets Depending on Jet Penetration Coefficient and Momentum Flux Ratio

    Science.gov (United States)

    Holdeman, James D.

    2016-01-01

    The purpose of this article is to explain why the extension of the previously published C = (S/Ho)sqrt(J) scaling for opposed rows of staggered jets wasn't directly successful in the study by Choi et al. (2016). It is not surprising that staggered jets from opposite sides do not pass each other at the expected C value, because Ho/D and sqrt(J) are much larger than the maximum in previous studies. These, and large x/D's, tend to suggest development of 2-dimensional flow. Although there are distinct optima for opposed rows of in-line jets, single-side injection, and opposed rows of staggered jets based on C, opposed rows of staggered jets provide as good or better mixing performance, at any C value, than opposed rows of in-line jets or jets from single-side injection.

  20. Integral staggered point-matching method for millimeter-wave reflective diffraction gratings on electron cyclotron heating systems

    International Nuclear Information System (INIS)

    Xia, Donghui; Huang, Mei; Wang, Zhijiang; Zhang, Feng; Zhuang, Ge

    2016-01-01

    Highlights: • The integral staggered point-matching method for design of polarizers on the ECH systems is presented. • The availability of the integral staggered point-matching method is checked by numerical calculations. • Two polarizers are designed with the integral staggered point-matching method and the experimental results are given. - Abstract: The reflective diffraction gratings are widely used in the high power electron cyclotron heating systems for polarization strategy. This paper presents a method which we call “the integral staggered point-matching method” for design of reflective diffraction gratings. This method is based on the integral point-matching method. However, it effectively removes the convergence problems and tedious calculations of the integral point-matching method, making it easier to be used for a beginner. A code is developed based on this method. The calculation results of the integral staggered point-matching method are compared with the integral point-matching method, the coordinate transformation method and the low power measurement results. It indicates that the integral staggered point-matching method can be used as an optional method for the design of reflective diffraction gratings in electron cyclotron heating systems.

  1. Pseudo-spectral method using rotated staggered grid for elastic wave propagation in 3D arbitrary anisotropic media

    KAUST Repository

    Zou, Peng

    2017-05-10

    Staggering grid is a very effective way to reduce the Nyquist errors and to suppress the non-causal ringing artefacts in the pseudo-spectral solution of first-order elastic wave equations. However, the straightforward use of a staggered-grid pseudo-spectral method is problematic for simulating wave propagation when the anisotropy level is greater than orthorhombic or when the anisotropic symmetries are not aligned with the computational grids. Inspired by the idea of rotated staggered-grid finite-difference method, we propose a modified pseudo-spectral method for wave propagation in arbitrary anisotropic media. Compared with an existing remedy of staggered-grid pseudo-spectral method based on stiffness matrix decomposition and a possible alternative using the Lebedev grids, the rotated staggered-grid-based pseudo-spectral method possesses the best balance between the mitigation of artefacts and efficiency. A 2D example on a transversely isotropic model with tilted symmetry axis verifies its effectiveness to suppress the ringing artefacts. Two 3D examples of increasing anisotropy levels demonstrate that the rotated staggered-grid-based pseudo-spectral method can successfully simulate complex wavefields in such anisotropic formations.

  2. Integral staggered point-matching method for millimeter-wave reflective diffraction gratings on electron cyclotron heating systems

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Donghui [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, 430074 Wuhan (China); Huang, Mei [Southwestern Institute of Physics, 610041 Chengdu (China); Wang, Zhijiang, E-mail: wangzj@hust.edu.cn [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, 430074 Wuhan (China); Zhang, Feng [Southwestern Institute of Physics, 610041 Chengdu (China); Zhuang, Ge [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, 430074 Wuhan (China)

    2016-10-15

    Highlights: • The integral staggered point-matching method for design of polarizers on the ECH systems is presented. • The availability of the integral staggered point-matching method is checked by numerical calculations. • Two polarizers are designed with the integral staggered point-matching method and the experimental results are given. - Abstract: The reflective diffraction gratings are widely used in the high power electron cyclotron heating systems for polarization strategy. This paper presents a method which we call “the integral staggered point-matching method” for design of reflective diffraction gratings. This method is based on the integral point-matching method. However, it effectively removes the convergence problems and tedious calculations of the integral point-matching method, making it easier to be used for a beginner. A code is developed based on this method. The calculation results of the integral staggered point-matching method are compared with the integral point-matching method, the coordinate transformation method and the low power measurement results. It indicates that the integral staggered point-matching method can be used as an optional method for the design of reflective diffraction gratings in electron cyclotron heating systems.

  3. EM reconstruction of dual isotope PET using staggered injections and prompt gamma positron emitters

    International Nuclear Information System (INIS)

    Andreyev, Andriy; Sitek, Arkadiusz; Celler, Anna

    2014-01-01

    Purpose: The aim of dual isotope positron emission tomography (DIPET) is to create two separate images of two coinjected PET radiotracers. DIPET shortens the duration of the study, reduces patient discomfort, and produces perfectly coregistered images compared to the case when two radiotracers would be imaged independently (sequential PET studies). Reconstruction of data from such simultaneous acquisition of two PET radiotracers is difficult because positron decay of any isotope creates only 511 keV photons; therefore, the isotopes cannot be differentiated based on the detected energy. Methods: Recently, the authors have proposed a DIPET technique that uses a combination of radiotracer A which is a pure positron emitter (such as 18 F or 11 C) and radiotracer B in which positron decay is accompanied by the emission of a high-energy (HE) prompt gamma (such as 38 K or 60 Cu). Events that are detected as triple coincidences of HE gammas with the corresponding two 511 keV photons allow the authors to identify the lines-of-response (LORs) of isotope B. These LORs are used to separate the two intertwined distributions, using a dedicated image reconstruction algorithm. In this work the authors propose a new version of the DIPET EM-based reconstruction algorithm that allows the authors to include an additional, independent estimate of radiotracer A distribution which may be obtained if radioisotopes are administered using a staggered injections method. In this work the method is tested on simple simulations of static PET acquisitions. Results: The authors’ experiments performed using Monte-Carlo simulations with static acquisitions demonstrate that the combined method provides better results (crosstalk errors decrease by up to 50%) than the positron-gamma DIPET method or staggered injections alone. Conclusions: The authors demonstrate that the authors’ new EM algorithm which combines information from triple coincidences with prompt gammas and staggered injections

  4. On the Quality of Velocity Interpolation Schemes for Marker-in-Cell Method and Staggered Grids

    Science.gov (United States)

    Pusok, Adina E.; Kaus, Boris J. P.; Popov, Anton A.

    2017-03-01

    The marker-in-cell method is generally considered a flexible and robust method to model the advection of heterogenous non-diffusive properties (i.e., rock type or composition) in geodynamic problems. In this method, Lagrangian points carrying compositional information are advected with the ambient velocity field on an Eulerian grid. However, velocity interpolation from grid points to marker locations is often performed without considering the divergence of the velocity field at the interpolated locations (i.e., non-conservative). Such interpolation schemes can induce non-physical clustering of markers when strong velocity gradients are present (Journal of Computational Physics 166:218-252, 2001) and this may, eventually, result in empty grid cells, a serious numerical violation of the marker-in-cell method. To remedy this at low computational costs, Jenny et al. (Journal of Computational Physics 166:218-252, 2001) and Meyer and Jenny (Proceedings in Applied Mathematics and Mechanics 4:466-467, 2004) proposed a simple, conservative velocity interpolation scheme for 2-D staggered grid, while Wang et al. (Geochemistry, Geophysics, Geosystems 16(6):2015-2023, 2015) extended the formulation to 3-D finite element methods. Here, we adapt this formulation for 3-D staggered grids (correction interpolation) and we report on the quality of various velocity interpolation methods for 2-D and 3-D staggered grids. We test the interpolation schemes in combination with different advection schemes on incompressible Stokes problems with strong velocity gradients, which are discretized using a finite difference method. Our results suggest that a conservative formulation reduces the dispersion and clustering of markers, minimizing the need of unphysical marker control in geodynamic models.

  5. Response of Maize Crop to Spatial Arrangement and Staggered Interseeding of Haricot Bean

    Directory of Open Access Journals (Sweden)

    Tamiru Hirpa

    2014-09-01

    Full Text Available Field studies conducted to determine the effects of intercrop row arrangements and staggered intercropping of haricot bean (Phaseolus vulgaris L. on the performances of maize (Zea mays L. crop at Hallaba and Taba areas in 2013 cropping season, southern Ethiopia, revealed that there were significant effects of cropping patterns and staggered interseeding of the legume component on growth and yield components of maize crop. Significant interaction of row arrangement × intercropping time of haricot bean was observed with respect to leaf area index (LAI of the maize crop. Increasing trends of LAI of maize crop were observed as interseeding of haricot bean was delayed for 3 weeks after maize (WAM that stabilized during the 6 WAM interseeding time. Maize stover production was significantly high at 1:2 row ratio and delaying of the undersowing haricot bean in the already established maize crop for 6 weeks, 10.94 tha-1 and 11.39 t ha-1, respectively. Maize grain yield showed a significant variation with respect to the staggered sowing of haricot bean, whereby the highest (3.99 t ha-1 being recorded when haricot bean intercropping was delayed for 21 days after maize planting. The data of this study revealed that the larger maize plant canopy providing larger photosynthetic area, attained when haricot bean interseeding was delayed, probably resulted in higher grain yield of maize. DOI: http://dx.doi.org/10.3126/ije.v3i3.11072 International Journal of Environment Vol.3(3 2014: 126-138

  6. EM reconstruction of dual isotope PET using staggered injections and prompt gamma positron emitters

    Science.gov (United States)

    Andreyev, Andriy; Sitek, Arkadiusz; Celler, Anna

    2014-01-01

    Purpose: The aim of dual isotope positron emission tomography (DIPET) is to create two separate images of two coinjected PET radiotracers. DIPET shortens the duration of the study, reduces patient discomfort, and produces perfectly coregistered images compared to the case when two radiotracers would be imaged independently (sequential PET studies). Reconstruction of data from such simultaneous acquisition of two PET radiotracers is difficult because positron decay of any isotope creates only 511 keV photons; therefore, the isotopes cannot be differentiated based on the detected energy. Methods: Recently, the authors have proposed a DIPET technique that uses a combination of radiotracer A which is a pure positron emitter (such as 18F or 11C) and radiotracer B in which positron decay is accompanied by the emission of a high-energy (HE) prompt gamma (such as 38K or 60Cu). Events that are detected as triple coincidences of HE gammas with the corresponding two 511 keV photons allow the authors to identify the lines-of-response (LORs) of isotope B. These LORs are used to separate the two intertwined distributions, using a dedicated image reconstruction algorithm. In this work the authors propose a new version of the DIPET EM-based reconstruction algorithm that allows the authors to include an additional, independent estimate of radiotracer A distribution which may be obtained if radioisotopes are administered using a staggered injections method. In this work the method is tested on simple simulations of static PET acquisitions. Results: The authors’ experiments performed using Monte-Carlo simulations with static acquisitions demonstrate that the combined method provides better results (crosstalk errors decrease by up to 50%) than the positron-gamma DIPET method or staggered injections alone. Conclusions: The authors demonstrate that the authors’ new EM algorithm which combines information from triple coincidences with prompt gammas and staggered injections improves

  7. Weak interaction matrix elements with staggered fermions. I: theory and a trial run

    International Nuclear Information System (INIS)

    Sharpe, S.R.; Patel, A.; Gupta, R.; Guralnik, G.; Kilsup, G.W.

    1986-08-01

    We present results of a preliminary study of the matrix elements of weak interaction operators using staggered fermions. We describe our method for transcribing the weak interaction Hamiltonian onto the lattice. This method preserves exact Ward Identities analogous to those of the continuum. The calculation uses operators involving 0, 1, 2, 3 and 4 gauge links. We present results for all these operators obtained on 8 3 x 16 lattices generated both with the Wilson action (β = 5.6) and an improved action

  8. Nucleon structure in the chiral regime with domain wall fermions on an improved staggered sea

    International Nuclear Information System (INIS)

    R.G. Edwards; G. Fleming; Ph. Hagler; J.W. Negele; K. Orginos; A.V. Pochinsky; D.B. Renner; D.G. Richards; W. Schroers

    2006-01-01

    Moments of unpolarized, helicity, and transversity distributions, electromagnetic form factors, and generalized form factors of the nucleon are presented from a preliminary analysis of lattice results using pion masses down to 359 MeV. The twist two matrix elements are calculated using a mixed action of domain wall valence quarks and asqtad staggered sea quarks and are renormalized perturbatively. Several observables are extrapolated to the physical limit using chiral perturbation theory. Results are compared with experimental moments of quark distributions and electromagnetic form factors and phenomenologically determined generalized form factors, and the implications on the transverse structure and spin content of the nucleon are discussed

  9. Aerodynamic drag of a staggered flat-oval finning tube banks at the small reynolds numbers

    Directory of Open Access Journals (Sweden)

    Максим Михайлович Вознюк

    2015-06-01

    Full Text Available Experimental investigations of aerodynamic drag of staggered bundles of flat-oval tubes with incomplete transversal fins in the range of Reynolds numbers 600 <  < 20000 are performed. New calculation correlations for determining of drag coefficients for 1<3000 are suggested, the impact of basic geometric and regime parameters on aerodynamic drag of bundles are determined. The received calculation depending is possible to use in developing of heat transfer surfaces for “dry” cooling towers and air cooling apparatus and economizers

  10. Calculation of cell face velocity of non-staggered grid system

    KAUST Repository

    Li, Wang

    2012-07-28

    In this paper, the cell face velocities in the discretization of the continuity equation, the momentum equation, and the scalar equation of a non-staggered grid system are calculated and discussed. Both the momentum interpolation and the linear interpolation are adopted to evaluate the coefficients in the discretized momentum and scalar equations. Their performances are compared. When the linear interpolation is used to calculate the coefficients, the mass residual term in the coefficients must be dropped to maintain the accuracy and convergence rate of the solution. © Shanghai University and Springer-Verlag Berlin Heidelberg 2012.

  11. Calculation of the Nucleon Axial Form Factor Using Staggered Lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Aaron S. [Fermilab; Hill, Richard J. [Perimeter Inst. Theor. Phys.; Kronfeld, Andreas S. [Fermilab; Li, Ruizi [Indiana U.; Simone, James N. [Fermilab

    2016-10-14

    The nucleon axial form factor is a dominant contribution to errors in neutrino oscillation studies. Lattice QCD calculations can help control theory errors by providing first-principles information on nucleon form factors. In these proceedings, we present preliminary results on a blinded calculation of $g_A$ and the axial form factor using HISQ staggered baryons with 2+1+1 flavors of sea quarks. Calculations are done using physical light quark masses and are absolutely normalized. We discuss fitting form factor data with the model-independent $z$ expansion parametrization.

  12. Cas9-catalyzed DNA Cleavage Generates Staggered Ends: Evidence from Molecular Dynamics Simulations

    Science.gov (United States)

    Zuo, Zhicheng; Liu, Jin

    2016-11-01

    The CRISPR-associated endonuclease Cas9 from Streptococcus pyogenes (spCas9) along with a single guide RNA (sgRNA) has emerged as a versatile toolbox for genome editing. Despite recent advances in the mechanism studies on spCas9-sgRNA-mediated double-stranded DNA (dsDNA) recognition and cleavage, it is still unclear how the catalytic Mg2+ ions induce the conformation changes toward the catalytic active state. It also remains controversial whether Cas9 generates blunt-ended or staggered-ended breaks with overhangs in the DNA. To investigate these issues, here we performed the first all-atom molecular dynamics simulations of the spCas9-sgRNA-dsDNA system with and without Mg2+ bound. The simulation results showed that binding of two Mg2+ ions at the RuvC domain active site could lead to structurally and energetically favorable coordination ready for the non-target DNA strand cleavage. Importantly, we demonstrated with our simulations that Cas9-catalyzed DNA cleavage produces 1-bp staggered ends rather than generally assumed blunt ends.

  13. Parametric modeling and stagger angle optimization of an axial flow fan

    International Nuclear Information System (INIS)

    Li, M X; Zhang, C H; Liu, Y; Zheng, S Y

    2013-01-01

    Axial flow fans are widely used in every field of social production. Improving their efficiency is a sustained and urgent demand of domestic industry. The optimization of stagger angle is an important method to improve fan performance. Parametric modeling and calculation process automation are realized in this paper to improve optimization efficiency. Geometric modeling and mesh division are parameterized based on GAMBIT. Parameter setting and flow field calculation are completed in the batch mode of FLUENT. A control program is developed in Visual C++ to dominate the data exchange of mentioned software. It also extracts calculation results for optimization algorithm module (provided by Matlab) to generate directive optimization control parameters, which as feedback are transferred upwards to modeling module. The center line of the blade airfoil, based on CLARK y profile, is constructed by non-constant circulation and triangle discharge method. Stagger angles of six airfoil sections are optimized, to reduce the influence of inlet shock loss as well as gas leak in blade tip clearance and hub resistance at blade root. Finally an optimal solution is obtained, which meets the total pressure requirement under given conditions and improves total pressure efficiency by about 6%

  14. Parametric modeling and stagger angle optimization of an axial flow fan

    Science.gov (United States)

    Li, M. X.; Zhang, C. H.; Liu, Y.; Y Zheng, S.

    2013-12-01

    Axial flow fans are widely used in every field of social production. Improving their efficiency is a sustained and urgent demand of domestic industry. The optimization of stagger angle is an important method to improve fan performance. Parametric modeling and calculation process automation are realized in this paper to improve optimization efficiency. Geometric modeling and mesh division are parameterized based on GAMBIT. Parameter setting and flow field calculation are completed in the batch mode of FLUENT. A control program is developed in Visual C++ to dominate the data exchange of mentioned software. It also extracts calculation results for optimization algorithm module (provided by Matlab) to generate directive optimization control parameters, which as feedback are transferred upwards to modeling module. The center line of the blade airfoil, based on CLARK y profile, is constructed by non-constant circulation and triangle discharge method. Stagger angles of six airfoil sections are optimized, to reduce the influence of inlet shock loss as well as gas leak in blade tip clearance and hub resistance at blade root. Finally an optimal solution is obtained, which meets the total pressure requirement under given conditions and improves total pressure efficiency by about 6%.

  15. Effect of wall proximity of two staggered triangular cylinders on the transport process in a channel

    Directory of Open Access Journals (Sweden)

    Mousa Farhadi

    2016-09-01

    Full Text Available A numerical investigation has been carried out to analyze the heat transfer and the flow field around two isothermal triangular cylinders of equal size placed staggered in a horizontal plane channel with adiabatic walls. Computations have been carried out for Reynolds numbers (based on triangle width 100, 250, and 350, lateral gap ratios (d/B 0, 0.5, and 1, and longitudinal gap ratios (S/B 1, 2, 3 and 4. The effect of longitudinal and lateral gap between obstacles and proximity of channel walls is investigated. Results show that when obstacles are placed in close vicinity of the channel's wall (d/B = 1, vortex shedding disappears at the downstream of triangles at Re = 100 and 250 at all S/B, but for Re = 350 creating and disappearing of the vortex shedding depend on the longitudinal gap ratio (S/B. Proximity of obstacles has more effect on the second triangle than the first triangle especially from longitudinal gap ratio equals 2, so that with approaching the channel wall, the Nusselt number for the first triangle decreases, while for the second triangle a different behavior is seen. Staggered arrangement causes the Nusselt number of the second triangle to become greater than the first triangle.

  16. Experimental study of thermal–hydraulic performance of cam-shaped tube bundle with staggered arrangement

    International Nuclear Information System (INIS)

    Bayat, Hamidreza; Lavasani, Arash Mirabdolah; Maarefdoost, Taher

    2014-01-01

    Highlights: • Thermal–hydraulic performance of a non-circular tube bundle has been investigated experimentally. • Tubes were mounted in staggered arrangement with two longitudinal pitch ratios 1.5 and 2. • Drag coefficient and Nusselt number of tubes in second row was measured. • Friction factor of this tube bundle is lower than circular tube bundle. • Thermal–hydraulic performance of this tube bundle is greater than circular tube bundle. - Abstract: Flow and heat transfer from cam-shaped tube bank in staggered arrangement is studied experimentally. Tubes were located in test section of an open loop wind tunnel with two longitudinal pitch ratios 1.5 and 2. Reynolds number varies in range of 27,000 ⩽ Re D ⩽ 42,500 and tubes surface temperature is between 78 and 85 °C. Results show that both drag coefficient and Nusselt number depends on position of tube in tube bank and Reynolds number. Tubes in the first column have maximum value of drag coefficient, while its Nusselt number is minimum compared to other tubes in tube bank. Moreover, pressure drop from this tube bank is about 92–93% lower than circular tube bank and as a result thermal–hydraulic performance of this tube bank is about 6 times greater than circular tube bank

  17. Analysis of the influence of the interlayer staggered zone in the basalt of Jinsha River Basin on the main buildings

    Science.gov (United States)

    Guo, Qiaona; Huang, Jiangwei

    2018-02-01

    In this paper, the finite element software FEFLOW is used to simulate the seepage field of the interlayer staggered zone C2 in the basalt of Jinsha River Basin. The influence of the interlayer staggered zone C2 on the building is analyzed. Combined with the waterproof effect of current design scheme of anti-seepage curtain, the seepage field in the interlayer staggered zone C2 is discussed under different design schemes. The optimal design scheme of anti-seepage curtain is put forward. The results showed that the case four can effectively reduce the head and hydraulic gradient of underground powerhouse area, and improve the groundwater seepage field in the plant area.

  18. Energy Stability Analysis of Some Fully Discrete Numerical Schemes for Incompressible Navier–Stokes Equations on Staggered Grids

    KAUST Repository

    Chen, Huangxin

    2017-09-01

    In this paper we consider the energy stability estimates for some fully discrete schemes which both consider time and spatial discretizations for the incompressible Navier–Stokes equations. We focus on three kinds of fully discrete schemes, i.e., the linear implicit scheme for time discretization with the finite difference method (FDM) on staggered grids for spatial discretization, pressure-correction schemes for time discretization with the FDM on staggered grids for the solutions of the decoupled velocity and pressure equations, and pressure-stabilization schemes for time discretization with the FDM on staggered grids for the solutions of the decoupled velocity and pressure equations. The energy stability estimates are obtained for the above each fully discrete scheme. The upwind scheme is used in the discretization of the convection term which plays an important role in the design of unconditionally stable discrete schemes. Numerical results are given to verify the theoretical analysis.

  19. High‐order rotated staggered finite difference modeling of 3D elastic wave propagation in general anisotropic media

    KAUST Repository

    Chu, Chunlei

    2009-01-01

    We analyze the dispersion properties and stability conditions of the high‐order convolutional finite difference operators and compare them with the conventional finite difference schemes. We observe that the convolutional finite difference method has better dispersion properties and becomes more efficient than the conventional finite difference method with the increasing order of accuracy. This makes the high‐order convolutional operator a good choice for anisotropic elastic wave simulations on rotated staggered grids since its enhanced dispersion properties can help to suppress the numerical dispersion error that is inherent in the rotated staggered grid structure and its efficiency can help us tackle 3D problems cost‐effectively.

  20. Towards corrections to the strong coupling limit of staggered lattice QCD

    CERN Document Server

    Fromm, Michael; Philipsen, Owe; de Forcrand, Philippe; Unger, Wolfgang; Miura, Kotaroh

    2011-01-01

    We report on the first steps of an ongoing project to add gauge observables and gauge corrections to the well-studied strong coupling limit of staggered lattice QCD, which has been shown earlier to be amenable to numerical simulations by the worm algorithm in the chiral limit and at finite density. Here we show how to evaluate the expectation value of the Polyakov loop in the framework of the strong coupling limit at finite temperature, allowing to study confinement properties along with those of chiral symmetry breaking. We find the Polyakov loop to rise smoothly, thus signalling deconfinement. The non-analytic nature of the chiral phase transition is reflected in the derivative of the Polyakov loop. We also discuss how to construct an effective theory for non-zero lattice coupling, which is valid to $O(\\beta)$.

  1. Field theory of a terahertz staggered double-grating arrays waveguide Cerenkov traveling wave amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Wenqiu; He, Fangming [Institute of Electronics, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wang, Zicheng; Luo, Jirun; Zhao, Ding; Liu, Qinglun [Institute of Electronics, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-04-15

    Based on a rectilinear sheet electron beam propagating through the tunnel of a staggered double-grating arrays waveguide (SDGAW) slow-wave structure (SWS), a three dimensional field theory for describing the modes and the beam-wave interaction is presented, in which the higher order terms inside the grooves are retained. The fields' distribution and the conductivity losses are also calculated utilizing the theoretical model. With the optimized parameters of the SWS and the electron beam, a 1 THz SDGAW Cerenkov traveling wave amplifier may obtain a moderate net gain (the peak gain is 12.7 dB/cm) and an ultra 3 dB wideband (0.19 THz) considering the serious Ohmic losses. The theoretical results have been compared with those calculated by 3D HFSS code and CST STUDIO particle-in-cell simulations.

  2. N{sub f}=1 QCD in external magnetic fields: staggered fermions

    Energy Technology Data Exchange (ETDEWEB)

    Cea, Paolo [INFN, Sezione di Bari, Via Amendola 173, I-70126 Bari (Italy); Dipartimento di Fisica dell’Università di Bari, Via Amendola 173, I-70126 Bari (Italy); Cosmai, Leonardo [INFN, Sezione di Bari, Via Amendola 173, I-70126 Bari (Italy)

    2015-12-10

    We investigate N{sub f}=1 QCD in external magnetic fields on the lattice. The background field is introduced by means of the so-called Schrödinger functional. We adopt standard staggered fermions with constant bare mass am=0.025 and magnetic fields with constant magnetic flux up to a{sup 2}eH≃2.3562. We find that the the deconfinement and chiral symmetry restoration temperatures do not depend on the strength of the applied magnetic field. Our method allow us to easily study the effects of the external magnetic fields on the QCD thermodynamics. We determine the influences of applied magnetic fields to the free energy, pressure, and equation of state of strongly interacting matter.

  3. Constitutive Modelling in Thermomechanical Processes, Using The Control Volume Method on Staggered Grid

    DEFF Research Database (Denmark)

    Thorborg, Jesper

    -strain relation has been suggested. The intention of this method is to provide fast numerical results with reasonable accuracy in relation to the first order effects of the presented classical plasticity model. Application of the $J_2$ flow theory and the alternative method have shown some agreement...... of the method has been focused on high temperature processes such as casting and welding and the interest of using nonlinear constitutive stress-strain relations has grown to extend the applicability of the method. The work of implementing classical plasticity into the control volume formulation has been based...... on the $J_2$ flow theory describing an isotropic hardening material with a temperature dependent yield stress. This work has successfully been verified by comparing results to analytical solutions. Due to the comprehensive implementation in the staggered grid an alternative constitutive stress...

  4. An arbitrary-order staggered time integrator for the linear acoustic wave equation

    Science.gov (United States)

    Lee, Jaejoon; Park, Hyunseo; Park, Yoonseo; Shin, Changsoo

    2018-02-01

    We suggest a staggered time integrator whose order of accuracy can arbitrarily be extended to solve the linear acoustic wave equation. A strategy to select the appropriate order of accuracy is also proposed based on the error analysis that quantitatively predicts the truncation error of the numerical solution. This strategy not only reduces the computational cost several times, but also allows us to flexibly set the modelling parameters such as the time step length, grid interval and P-wave speed. It is demonstrated that the proposed method can almost eliminate temporal dispersive errors during long term simulations regardless of the heterogeneity of the media and time step lengths. The method can also be successfully applied to the source problem with an absorbing boundary condition, which is frequently encountered in the practical usage for the imaging algorithms or the inverse problems.

  5. Staggered-Grid Finite Difference Method with Variable-Order Accuracy for Porous Media

    Directory of Open Access Journals (Sweden)

    Jinghuai Gao

    2013-01-01

    Full Text Available The numerical modeling of wave field in porous media generally requires more computation time than that of acoustic or elastic media. Usually used finite difference methods adopt finite difference operators with fixed-order accuracy to calculate space derivatives for a heterogeneous medium. A finite difference scheme with variable-order accuracy for acoustic wave equation has been proposed to reduce the computation time. In this paper, we develop this scheme for wave equations in porous media based on dispersion relation with high-order staggered-grid finite difference (SFD method. High-order finite difference operators are adopted for low-velocity regions, and low-order finite difference operators are adopted for high-velocity regions. Dispersion analysis and modeling results demonstrate that the proposed SFD method can decrease computational costs without reducing accuracy.

  6. Stress analysis of three-dimensional roadway layout of stagger arrangement with field observation

    Science.gov (United States)

    Cui, Zimo; Chanda, Emmanuel; Zhao, Jingli; Wang, Zhihe

    2018-01-01

    Longwall top-coal caving (LTCC) has been a popular, more productive and cost-effective method for extracting thick (> 5 m) to ultra-thick coal seams in recent years. However, low-level recovery ratio of coal resources and top-coal loss above the supports at both ends of working face are long-term problems. Geological factors, such as large dip angle, soft rock, mining depth further complicate the problems. This paper proposes addressing this issue by adopting three-dimensional roadway layout of stagger arrangement (3-D RLSA). In this study, the first step was to analyse the stress environment surrounding head entry in the replacing working face based on the stress distribution characteristics at the triangular coal-pillar side in gob and the stress slip line field theory. In the second step, filed observation was conducted. Finally, an economic evaluation of the 3-D RLSA for extracting thick to ultra-thick seams was conducted.

  7. Cellular uptake of magnetite nanoparticles enhanced by NdFeB magnets in staggered arrangement

    Science.gov (United States)

    Lu, Yi-Ching; Chang, Fan-Yu; Tu, Shu-Ju; Chen, Jyh-Ping; Ma, Yunn-Hwa

    2017-04-01

    Magnetic force may greatly enhance uptake of magnetic nanoparticles (MNPs) by cultured cells; however, the effects of non-uniformity of magnetic field/ magnetic gradient on MNP internalization in culture has not been elucidated. Cellular uptake of polyacrylic acid coated-MNP by LN229 cells was measured with cylindrical NdFeB magnets arranged in a staggered pattern. The magnetic field generated by placing a magnet underneath (H-field) elicited a homogenous distribution of MNPs on the cells in culture; whereas the field without magnet underneath (L-field) resulted in MNP distribution along the edge of the wells. Cell-associated MNP (MNPcell) appeared to be magnetic field- and concentration-dependent. In H-field, MNPcell reached plateau within one hour of exposure to MNP with only one-min application of the magnetic force in the beginning of incubation; continuous presence of the magnet for 2 h did not further increase MNPcell, suggesting that magnetic force-induced uptake may be primarily contributed to enhanced MNP sedimentation. Although MNP distribution was much inhomogeneous in L-field, averaged MNPcell in the L-field may reach as high as 80% of that in H-field during 1-6 h incubation, suggesting high capacity of MNP internalization. In addition, no significant difference was observed in MNPcell analyzed by flow cytometry with the application of H-field of staggered plate vs. filled magnet plate. Therefore, biological variation may dominate MNP internalization even under relatively uniformed magnetic field; whereas non-uniformed magnetic field may serve as a model for tumor targeting with MNPs in vivo.

  8. A comparative study of Purkinje cells in two RORalpha gene mutant mice: staggerer and RORalpha(-/-).

    Science.gov (United States)

    Doulazmi, M; Frédéric, F; Capone, F; Becker-André, M; Delhaye-Bouchaud, N; Mariani, J

    2001-04-30

    The staggerer (Rora(sg/sg)) mutation is a deletion in the RORalpha gene, one member of a family of nuclear receptor genes related to the retinoic acid receptor. Recently Steinmayr et al. (Proc. Natl. Acad. Sci. USA 95 (1998) 3960) generated a RORalpha null-mutant mouse (Rora(-/-)) by using a targeting vector in which a beta-Gal gene replaces the second finger of the DNA-binding domain of RORalpha. The Rora(-/-) cerebellum is qualitatively a phenocopy of the Rora(sg/sg) one, but the two strains differ slightly in their motor skills. To address the question whether the morphological defects in the Rora(-/-) cerebellum are identical to the Rora(sg/sg) one, we compared number and size of Purkinje cells in both staggerer and RORalpha null-mutant mice, using calbindin (CaBP) immunohistochemistry and revelation of beta-Gal activity. Compared to control cerebella the Rora(sg/sg) cerebellum has 82% fewer CaBP-positive cells. In Rora(-/-) mouse, all the the beta-Gal-positive Purkinje cells also expressed CaBP, but the cerebellum contained 78% less CaBP-positive cells than control, a deficit not different from the one observed in Rora(sg/sg). We show similar mediolateral compartments in Purkinje cell number and cytological abnormality in Rora(sg/sg) and Rora(-/-) mice. These results provide quantitative support for the hypothesis that the cerebellar phenotype in the homozygous Rora(sg/sg) is due to the lack of function of the RORalpha gene.

  9. Investigation of analog/RF performance of staggered heterojunctions based nanowire tunneling field-effect transistors

    Science.gov (United States)

    Chakraborty, Avik; Sarkar, Angsuman

    2015-04-01

    In this paper, the analog/RF performance of an III-V semiconductor based staggered hetero-tunnel-junction (HETJ) n-type nanowire (NW) tunneling FET (n-TFET) is investigated, for the first time. The device performance figure-of-merits governing the analog/RF performance such as transconductance (gm), transconductance-to-drive current ratio (gm/IDS), output resistance (Rout), intrinsic gain and unity-gain cutoff frequency (fT) have been studied. The analog/RF performance parameters is compared between HETJ NW TFET and a homojunction (HJ) NW n-type TFET of similar dimensions. In addition to enhanced ION and subthreshold swing, a significant improvement in the analog/RF performance parameters obtained by the HETJ n-TFET over HJ counterpart for use in analog/mixed signal System-on-Chip (SoC) applications is reported. Moreover, the analog/RF performance parameters of a III-V based staggered HETJ NW TFET is also compared with a heterojunction (HETJ) NW n-type MOSFET having same material as HETJ n-TFET and equal dimension in order to provide a systematic comparison between HETJ-TFET and HETJ-MOSFET for use in analog/mixed-signal applications. The results reveal that HETJ n-TFET provides higher Rout and hence, a higher intrinsic gain, an improved gm/IDS ratio, and reasonable fT at lower values of gate-overdrive voltage as compared to the HETJ NW n-MOSFET.

  10. A Study of a Powder Coating Gun Near Field: Particle Flow in an Isothermal Staggered Concentric Air Jet

    Directory of Open Access Journals (Sweden)

    Graham Payne

    2014-07-01

    Full Text Available An experimental study of inert particle dispersion in an isothermal concentric air jet near field was conducted for cases of standard non-staggered and alternative staggered jet nozzles, each taken from a polymer powder flame deposition gun. The experimental work consisted of analysis of high speed digital images of the inert two phase isothermal jet flow, illuminated by a laser light sheet along and across the jet axis. The analysis of particle spread in the jet, represented by families of particle density distributions, clearly showed that the staggered nozzles resulted in a better-focused flow, with narrower distributions in the near field, and in the elimination of the recirculation zone that disrupted the particle flow in a non-staggered nozzle arrangement. In all cases, histograms of the cross-sectional particle area density were found to be approximately Gaussian. It was also found that there was a wide variation in the size and shape of the ground polymer particles used and these two characteristics caused a wide variation in the radial and axial velocities of the particles. Despite the differences between single-phase numerical simulations and experimental results, reported in Payne et al. [1], the introduction of particles into a numerical model produced satisfactory agreement with the particle velocities found experimentally.

  11. The sequential organ failure assessment (SOFA) score is an effective triage marker following staggered paracetamol (acetaminophen) overdose.

    Science.gov (United States)

    Craig, D G; Zafar, S; Reid, T W D J; Martin, K G; Davidson, J S; Hayes, P C; Simpson, K J

    2012-06-01

    The sequential organ failure assessment (SOFA) score is an effective triage marker following single time point paracetamol (acetaminophen) overdose, but has not been evaluated following staggered (multiple supratherapeutic doses over >8 h, resulting in cumulative dose of >4 g/day) overdoses. To evaluate the prognostic accuracy of the SOFA score following staggered paracetamol overdose. Time-course analysis of 50 staggered paracetamol overdoses admitted to a tertiary liver centre. Individual timed laboratory samples were correlated with corresponding clinical parameters and the daily SOFA scores were calculated. A total of 39/50 (78%) patients developed hepatic encephalopathy. The area under the SOFA receiver operator characteristic for death/liver transplantation was 87.4 (95% CI 73.2-95.7), 94.3 (95% CI 82.5-99.1), and 98.4 (95% CI 84.3-100.0) at 0, 24 and 48 h, respectively, postadmission. A SOFA score of paracetamol overdose, is associated with a good prognosis. Both the SOFA and APACHE II scores could improve triage of high-risk staggered paracetamol overdose patients. © 2012 Blackwell Publishing Ltd.

  12. Staggered overdose pattern and delay to hospital presentation are associated with adverse outcomes following paracetamol-induced hepatotoxicity.

    Science.gov (United States)

    Craig, Darren G N; Bates, Caroline M; Davidson, Janice S; Martin, Kirsty G; Hayes, Peter C; Simpson, Kenneth J

    2012-02-01

    Paracetamol (acetaminophen) poisoning remains the major cause of severe acute hepatotoxicity in the UK. In this large single centre cohort study we examined the clinical impact of staggered overdoses and delayed presentation following paracetamol overdose. Between 1992 and 2008, 663 patients were admitted with paracetamol-induced severe liver injury, of whom 161 (24.3%) had taken a staggered overdose. Staggered overdose patients were significantly older and more likely to abuse alcohol than single time point overdose patients. Relief of pain (58.2%) was the commonest rationale for repeated supratherapeutic ingestion. Despite lower total ingested paracetamol doses and lower admission serum alanine aminotransferase concentrations, staggered overdose patients were more likely to be encephalopathic on admission, require renal replacement therapy or mechanical ventilation and had higher mortality rates compared with single time point overdoses (37.3% vs. 27.8%, P= 0.025), although this overdose pattern did not independently predict death. The King's College poor prognostic criteria had reduced sensitivity (77.6, 95% CI 70.8, 81.5) for this pattern of overdose. Of the 396/450 (88.0%) single time point overdoses in whom accurate timings could be obtained, 178 (44.9%) presented to medical services >24 h following overdose. Delayed presentation beyond 24 h post overdose was independently associated with death/liver transplantation (OR 2.25, 95% CI 1.23, 4.12, P= 0.009). Both delayed presentation and staggered overdose pattern are associated with adverse outcomes following paracetamol overdose. These patients are at increased risk of developing multi-organ failure and should be considered for early transfer to specialist liver centres. © 2011 The Authors. British Journal of Clinical Pharmacology © 2011 The British Pharmacological Society.

  13. Cellular uptake of magnetite nanoparticles enhanced by NdFeB magnets in staggered arrangement

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yi-Ching; Chang, Fan-Yu [Department of Physiology and Pharmacology & Healthy Aging Research Center, Guishan, Taoyuan City 33302, Taiwan, ROC (China); Tu, Shu-Ju [Department of Medical Imaging and Radiological Sciences, Chang Gung University, Guishan, Taoyuan City 33302, Taiwan, ROC (China); Chen, Jyh-Ping [Department of Chemical and Materials Engineering, Chang Gung University, Guishan, Taoyuan City 33302, Taiwan, ROC (China); Ma, Yunn-Hwa, E-mail: yhma@mail.cgu.edu.tw [Department of Physiology and Pharmacology & Healthy Aging Research Center, Guishan, Taoyuan City 33302, Taiwan, ROC (China); Department of Neurology, Chang Gung Memorial Hospital, Guishan, Taoyuan City 33305, Taiwan, ROC (China)

    2017-04-01

    Magnetic force may greatly enhance uptake of magnetic nanoparticles (MNPs) by cultured cells; however, the effects of non-uniformity of magnetic field/ magnetic gradient on MNP internalization in culture has not been elucidated. Cellular uptake of polyacrylic acid coated-MNP by LN229 cells was measured with cylindrical NdFeB magnets arranged in a staggered pattern. The magnetic field generated by placing a magnet underneath (H-field) elicited a homogenous distribution of MNPs on the cells in culture; whereas the field without magnet underneath (L-field) resulted in MNP distribution along the edge of the wells. Cell-associated MNP (MNP{sub cell}) appeared to be magnetic field- and concentration-dependent. In H-field, MNP{sub cell} reached plateau within one hour of exposure to MNP with only one-min application of the magnetic force in the beginning of incubation; continuous presence of the magnet for 2 h did not further increase MNP{sub cell}, suggesting that magnetic force-induced uptake may be primarily contributed to enhanced MNP sedimentation. Although MNP distribution was much inhomogeneous in L-field, averaged MNP{sub cell} in the L-field may reach as high as 80% of that in H-field during 1–6 h incubation, suggesting high capacity of MNP internalization. In addition, no significant difference was observed in MNP{sub cell} analyzed by flow cytometry with the application of H-field of staggered plate vs. filled magnet plate. Therefore, biological variation may dominate MNP internalization even under relatively uniformed magnetic field; whereas non-uniformed magnetic field may serve as a model for tumor targeting with MNPs in vivo. - Graphical abstract: Averaged MNP uptake by glioma cells in the low and non-uniformed magnetic field reached as high as 80% of that in uniformed magnetic field, which is probably due to both heterogeneous distributions of MNPs in the non-uniformed magnetic field and high capacity of the MNP uptake by these cells. - Highlights:

  14. An effective method for smoothing the staggered dose distribution of multi-leaf collimator field edge

    International Nuclear Information System (INIS)

    Hwang, I.-M.; Lin, S.-Y.; Lee, M.-S.; Wang, C.-J.; Chuang, K.-S.; Ding, H.-J.

    2002-01-01

    Purpose: To smooth the staggered dose distribution that occurs in stepped leaves defined by a multi-leaf collimator (MLC). Materials and methods: The MLC Shaper program controlled the stepped leaves, which were shifted in a traveling range, the pattern of shift was from the position of out-bound to in-bound with a one-segment (cross-bound), three-segment, and five-segment shifts. Film was placed at a depth of 1.5 cm and irradiated with the same irradiation dose used for the cerrobend block experiment. Four field edges with the MLC defining at 15 deg., 30 deg., 45 deg., 60 deg. angels relative to the jaw edge were performed, respectively, in this study. For the field edge defined by the multi-segment technique, the amplitude of the isodose lines for 50% isodose line and both the 80% and 20% isodose lines were measured. The effective penumbra widths with 90-10% and 80-20% distances for different irradiations were determined at four field edges with the MLC defining at 15 deg., 30 deg., 45 deg., 60 deg. angels relative to the jaw edge. Results: Use of the five-segment technique for multi-leaf collimation at the 60 deg. angle field edge smoothes each isodose line into an effectively straight line, similar to the pattern achieved using a cerrobend block. The separation of these lines is also important. The 80-20% effective penumbra width with five-segment techniques (8.23 mm) at 60 deg. angle relative to the jaw edge is little wider (1.9 times) than the penumbra of cerrobend block field edge (4.23 mm). We also found that the 90-10% effective penumbra width with five-segment techniques (12.68 mm) at 60 deg. angle relative to the jaw edge is little wider (1.28 times) than the penumbra of cerrobend block field edge (9.89 mm). Conclusion: The multi-segment technique is effective in smoothing the MLC staggered field edge. The effective penumbra width with more segment techniques at larger degree angles relative to the field edge is little wider than the penumbra for a

  15. A Study of a Powder Coating Gun near Field: A Case of Staggered Concentric Jet Flow

    Directory of Open Access Journals (Sweden)

    Edward Grandmaison

    2013-11-01

    Full Text Available This paper examines, experimentally and numerically, an isothermal coaxial air jet, created by an innovative nozzle design for an air propane torch, used for the thermal deposition of polymers. This design includes staggering the origins of the central and annular jets and creating an annular air jet with an inward radial velocity component. The experimental work used a Pitot tube to measure axial velocity on the jet centerline and in the fully developed flow. The static gauge pressure in the near field was also measured and found to be positive, an unexpected result. The numerical work used Gambit and Fluent. An extensive grid sensitivity study was conducted and it was found that results from a relatively coarse mesh were substantially the same as results from a mesh with almost 11 times the number of control volumes. A thorough evaluation of all of the RANS models in Fluent 6.3.26 found that the flow fields they calculated showed at most partial agreement with the experimental results. The greatest difference between numerical and experimental results was the incorrect prediction by all RANS models of a recirculation zone in the near field on the jet axis. Experimental work showed it did not exist.

  16. The interference between two flat plates normal to a stream in staggered arrangement, 1

    International Nuclear Information System (INIS)

    Hirano, Kimitaka; Kawashima, Akira; Ohsako, Hideyuki.

    1983-01-01

    The clarification of the mutual interference characteristics between the bodies with sharp corners, such as flat plates and rectangular prisms placed perpendicularly to flow, is a fundamental and important problem. But it has not yet been sufficiently clarified. In flat plates, the points of breaking away do not move, a large breaking away region is in the wake, and the thickness is very thin in the direction of main flow. Moreover, a moment arises around the center of flat plates. In this study, a new parameter expressing the influence of channel walls on a single flat plate in the measuring part of two-dimensional wind tunnel experiment was proposed. The change of steady drag coefficient and Strouhal number corresponding to the series and parallel arrangements of two plates was clarified, and the patterns of the mutual interference were classified by using the results of visualizing flow in a circulation tank together. By the experimental results in the widely changed staggered arrangements, the isodrag contour diagram and isomoment contour diagram were drawn, and the general characteristics of mutual interference related to steady drag and moment were clarified. The experimental setup and method and the results are reported. (Kako, I.)

  17. Natural convection heat transfer for a staggered array of heated, horizontal cylinders within a rectangular enclosure

    Energy Technology Data Exchange (ETDEWEB)

    Triplett, C.E.

    1996-12-01

    This thesis presents the results of an experimental investigation of natural convection heat transfer in a staggered array of heated cylinders, oriented horizontally within a rectangular enclosure. The main purpose of this research was to extend the knowledge of heat transfer within enclosed bundles of spent nuclear fuel rods sealed within a shipping or storage container. This research extends Canaan`s investigation of an aligned array of heated cylinders that thermally simulated a boiling water reactor (BWR) spent fuel assembly sealed within a shipping or storage cask. The results are presented in terms of piecewise Nusselt-Rayleigh number correlations of the form Nu = C(Ra){sup n}, where C and n are constants. Correlations are presented both for individual rods within the array and for the array as a whole. The correlations are based only on the convective component of the heat transfer. The radiative component was calculated with a finite-element code that used measured surface temperatures, rod array geometry, and measured surface emissivities as inputs. The correlation results are compared to Canaan`s aligned array results and to other studies of natural convection in horizontal tube arrays.

  18. Natural convection heat transfer for a staggered array of heated, horizontal cylinders within a rectangular enclosure

    International Nuclear Information System (INIS)

    Triplett, C.E.

    1996-12-01

    This thesis presents the results of an experimental investigation of natural convection heat transfer in a staggered array of heated cylinders, oriented horizontally within a rectangular enclosure. The main purpose of this research was to extend the knowledge of heat transfer within enclosed bundles of spent nuclear fuel rods sealed within a shipping or storage container. This research extends Canaan's investigation of an aligned array of heated cylinders that thermally simulated a boiling water reactor (BWR) spent fuel assembly sealed within a shipping or storage cask. The results are presented in terms of piecewise Nusselt-Rayleigh number correlations of the form Nu = C(Ra) n , where C and n are constants. Correlations are presented both for individual rods within the array and for the array as a whole. The correlations are based only on the convective component of the heat transfer. The radiative component was calculated with a finite-element code that used measured surface temperatures, rod array geometry, and measured surface emissivities as inputs. The correlation results are compared to Canaan's aligned array results and to other studies of natural convection in horizontal tube arrays

  19. Development of Non-staggered, SMAC numerical scheme for a two-fluid model

    International Nuclear Information System (INIS)

    Yoon, H. Y.; Jeong, Jae Jun

    2007-06-01

    The SMAC(Simplified Marker And Cell) method, along with the SIMPLE, has long been used efficiently for the computational fluid dynamics. Usually, the majority of the applications are single phase compressible or incompressible fluids, and the numerical methods are to be modified to implement the following items for the analysis of two-phase flows. - Non-staggered grid for the analysis of a complex geometry - Application of the two-phase models - Coupling of the energy conservation equations - Two-phase flows with phase change. In this report, the SMAC Method is reviewed and extended to compressible two-phase flows with phase change. A pilot code CUPID-M is developed using the proposed numerical method. A set of verification calculations are carried out for th CUPID-M. At first, isothermal air-water flow is simulated to verify the numerical method against two-phase flow flow problems. Next, the two-phase flows with phase change are calculated using CUPID-M and the results are compared to that of CUPID-I, which is based on the coupled ICE method. The calculation time is shorter with CUPID-M than with CUPID-I, while the calculations are unstable with CUPID-M for the rapid phase change problems. Thus, CUPID-M and CUPID-I can be used as an user input considering the application problems

  20. An analytical solution for contact resistance of staggered organic field-effect transistors

    Science.gov (United States)

    Karimi-Alavijeh, Hamidreza; Katebi-Jahromi, Alireza

    2017-03-01

    We have developed analytical models for bias dependent contact resistance (RC) and output characteristics of staggered organic field-effect transistors (OFETS) based on a bulk resistance-approximated and mobility-modified current-crowding method. Numerical evaluations of RC and its resistive components show that the bias dependency of the bulk resistance is negligible. Consequently, the properties of the active layer interfaces determine RC and its characteristics. Effective parameters include a normally constant charge injection barrier at the organic-metal interface (Eb) and a gate induced surface carrier-concentration (PS0) at the organic-insulator boundary. The energy barrier pertains to the fabrication process, and its related resistance (rc) can be determined as the fitting parameter of the theoretical model. However, PS0 is strongly gate bias dependent and the results of the numerical model indicate that the resulting component (rch) is dominant and has a considerable effect on RC and its characteristics. More importantly, PS0 as the key parameter of the contact resistance is analytically expressible and by using a proposed mobility-modified current-crowding model, the contact resistance can be analytically formulated. Accordingly, the output characteristics of the OFETs in the triode region can be also analytically modeled using the developed relation of RC.

  1. Large odd-even staggering in the very light platinum isotopes from laser spectroscopy

    CERN Document Server

    Le Blanc, F; Cabaret, L A; Crawford, J E; Duong, H T; Genevey, J; Girod, M; Huber, G; Krieg, M; Lee, J K P; Lettry, Jacques; Lunney, M D; Obert, J; Oms, J; Peru, S; Putaux, J C; Roussière, B; Sauvage, J; Sebastian, V; Zemlyanoi, S G

    1998-01-01

    Laser spectroscopy measurements have been carried out on very neutron-deficient platinum isotopes with the COMPLIS experimental set-up on line with the ISOLDE-Booster facility. For the first time, Hg alpha -decay was exploited to extend the very light platinum chain. Using the 5d/sup 9/6s /sup 3/D/sub 3/ to 5d/sup 9/6p /sup 3/P /sub 2/ optical transition, hyperfine spectra of /sup 182,181,180,179,178/Pt and /sup 183/Pt/sup m/ were recorded for the first time. The variation of the mean square charge radius between these nuclei, the magnetic moments of the odd isotopes and the quadrupole moment of /sup 183/Pt/sup m/ were thus measured. A large deformation change between /sup 183/Pt/sup 9/ and /sup 183/Pt/sup m/, an odd-even staggering of the charge radius and a deformation drop from A=179 are clearly observed. All these results are discussed and compared with microscopic theoretical predictions using Hartree-Fock- Bogolyubov calculations using the Gogny force. (20 refs).

  2. The Effect of First-Step Techniques from the Staggered Stance in American Football

    DEFF Research Database (Denmark)

    Knudsen, Nikolas Sten; Andersen, Thomas Bull

    2017-01-01

    The purpose of this study was to evaluate 3 different starting techniques from the staggered stance with regards to sprint time, reaction time, linear impulse and power. 11 male amateur American football players volunteered to participate in a testing session consisting of twelve 5 m sprints, 4...... in each technique (normal (NORM), backwards false step (BFS) and forwards false step (FFS)) in random order. Sprint starts were performed on force plates to investigate ground reaction forces, reaction time and total sprint time. Analysis showed significant differences in sprint times, with NORM (1.......77±0.10 s) being faster than FFS (1.81±0.12 s) and BFS (2.01±0.13 s), and FFS being faster than BFS, although no differences were found in reaction time. In terms of mean force and power, NORM (331.1±39.2N, 542.2±72.3W) and FFS (320.8±43.2N, 550.9±81.4W) were significantly larger than BFS (256.9±36.2N, 443...

  3. Performance Analysis and Modeling of a Tubular Staggered-Tooth Transverse-Flux PM Linear Machine

    Directory of Open Access Journals (Sweden)

    Shaohong Zhu

    2016-03-01

    Full Text Available This paper investigates the performance analysis and mathematical modeling of a staggered-tooth transverse-flux permanent magnet linear synchronous machine (STTF-PMLSM, which is characterized by simple structure and low flux leakage. Firstly, the structure advantages and operation principle of the STTF-PMLSM are introduced, and a simplified one phase model is established to investigate the performance of the machine in order to save the computation time. Then, the electromagnetic characteristics, including no-load flux linkage, electromotive force (EMF, inductance, detent force and thrust force, are simulated and analyzed in detail. After that, the theoretical analysis of the detent force, thrust force, and power factor are carried out. And the theoretical analysis results are validated with 3-D finite-element method (FEM. Finally, an improved mathematical model of the machine based on d-q rotating coordinate system is proposed, in which inductance harmonics and coupling between d- and q-axis inductance is considered. The results from the proposed mathematical model are in accordance with the results from 3-D FEM, which proves the validity and effectiveness of the proposed mathematical model. This provides a powerful foundation for the control of the machine.

  4. Dave Eggers's a heartbreaking work of staggering genius: memoir as a "pain-relief device".

    Science.gov (United States)

    Miller, Elise

    2011-10-01

    Dave Eggers's memoir is an important addition to the tradition of autobiography in America, and offers significant contributions to our understanding of creativity, sublimation, and the psychology of the memoir-writing process. A Heartbreaking Work of Staggering Genius is really two books--an autobiographical narrative about unbearable suffering, and a book of psychoanalytic commentary on the challenges of writing a memoir about catastrophic loss and trauma. The main narrative suggests the psychological resilience it takes to contain unbearable suffering. The metanarrative renders transparent the mind of someone who is both remembering his losses and constantly reflecting upon the process of writing about them. Eggers's identification with authorship, rather than bereavement or traumatization, may have played an important role in containing his affect and his sense of self when the heartbreaking events were originally unfolding. But a price is paid when a son uses his art to construct a new identity as an author--unconscious conflicts, primitive affect, anxieties about failing, as well as guilt about succeeding--consequences often missed by readers. Heartbreaking is a palimpsest, a story about story-telling superimposed on tales of death and survival, but its messages will be missed unless all its parts are preserved when being read or studied.

  5. Exploration of the horizontally staggered light guides for high concentration CPV applications.

    Science.gov (United States)

    Selimoglu, Ozgur; Turan, Rasit

    2012-08-13

    The material and processing costs are still the major drawbacks of the c-Si based photovoltaic (PV) technology. The wafer cost comprises up to 35-40% of the total module cost. New approaches and system designs are needed in order to reduce the share of the wafer cost in photovoltaic energy systems. Here we explore the horizontally staggered light guide solar optics for use in Concentrated Photovoltaic (CPV) applications. This optical system comprises a lens array system coupled to a horizontal light guide which directs the incoming light beam to its edge. We have designed and simulated this system using a commercial ray tracing software (Zemax). The system is more compact, thinner and more robust compared to the conventional CPV systems. Concentration levels as high as 1000x can easily be reached when the system is properly designed. With such a high concentration level, a good acceptance angle of + -1 degree is still be conserved. The analysis of the system reveals that the total optical efficiency of the system could be as high as %94.4 without any anti-reflection (AR) coating. Optical losses can be reduced by just accommodating a single layer AR coating on the initial lens array leading to a %96.5 optical efficiency. Thermal behavior of high concentration linear concentrator is also discussed and compared with a conventional point focus CPV system.

  6. Chiral phase transition of three flavor QCD with nonzero magnetic field using standard staggered fermions

    Science.gov (United States)

    Tomiya, Akio; Ding, Heng-Tong; Mukherjee, Swagato; Schmidt, Christian; Wang, Xiao-Dan

    2018-03-01

    Lattice simulations for (2+1)-flavor QCD with external magnetic field demon-strated that the quark mass is one of the important parameters responsible for the (inverse) magnetic catalysis. We discuss the dependences of chiral condensates and susceptibilities, the Polyakov loop on the magnetic field and quark mass in three degenerate flavor QCD. The lattice simulations are performed using standard staggered fermions and the plaquette action with spatial sizes Nσ = 16 and 24 and a fixed temporal size Nτ = 4. The value of the quark masses are chosen such that the system undergoes a first order chiral phase transition and crossover with zero magnetic field. We find that in light mass regime, the quark chiral condensate undergoes magnetic catalysis in the whole temperature region and the phase transition tend to become stronger as the magnetic field increases. In crossover regime, deconfinement transition temperature is shifted by the magnetic field when quark mass ma is less than 0:4. The lattice cutoff effects are also discussed.

  7. Ginsparg-Wilson pions scattering in a sea of staggered quarks

    International Nuclear Information System (INIS)

    Chen, J.-W.; O'Connell, Donal; Van de Water, Ruth; Walker-Loud, Andre

    2006-01-01

    We calculate isospin 2 pion-pion scattering in chiral perturbation theory for a partially quenched, mixed action theory with Ginsparg-Wilson valence quarks and staggered sea quarks. We point out that for some scattering channels, the power-law volume dependence of two-pion states in nonunitary theories such as partially quenched or mixed action QCD is identical to that of QCD. Thus one can extract infinite-volume scattering parameters from mixed action simulations. We then determine the scattering length for both 2 and 2+1 sea quarks in the isospin limit. The scattering length, when expressed in terms of the pion mass and the decay constant measured on the lattice, has no contributions from mixed valence-sea mesons, thus it does not depend upon the parameter, C Mix , that appears in the chiral Lagrangian of the mixed theory. In addition, the contributions which nominally arise from operators appearing in the mixed action O(a 2 m q ) Lagrangian exactly cancel when the scattering length is written in this form. This is in contrast to the scattering length expressed in terms of the bare parameters of the chiral Lagrangian, which explicitly exhibits all the sicknesses and lattice spacing dependence allowed by a partially quenched mixed action theory. These results hold for both 2 and 2+1 flavors of sea quarks

  8. Animal physiology and genetic aspects of ryegrass staggers in grazing sheep.

    Science.gov (United States)

    Morris, C A; Wheeler, T T; Henderson, H V; Towers, N R; Phua, S H

    2017-07-01

    Ryegrass staggers (RGS) is a metabolic disease of herbivores, caused by the ingestion of perennial ryegrass (Lolium perenne L.) containing a fungal endophyte (Neotyphodium lolii) which produces a tremorgenic toxin, lolitrem B. RGS has a major economic impact for agriculture in New Zealand as well as internationally. Management of RGS in grazing sheep can be problematic, and there is an incomplete knowledge of the interaction between the toxin and the grazing animal. This review is focused on recent advances in understanding the molecular physiology of RGS in the affected animal as well as the influence of animal genetics on the degree of susceptibility to RGS. Investigations to date suggest that the primary target for toxin is the large conductance, calcium-activated, potassium (BK) channel, resulting in disruption of neuromuscular junction signalling. Genetic investigation has established the existence of genes influencing resistance to RGS, however their identity has not been confirmed and their impact has not been established. Studies to date suggest that a multi-gene selection approach will be necessary in order to develop an effective selection tool for use in the agricultural industries.

  9. Nuclear shape staggering in very neutron deficient Hg isotopes detected by laser spectroscopy

    International Nuclear Information System (INIS)

    Dabkiewicz, P.; Duke, C.; Fischer, H.; Kuehl, T.; Kluge, H.-J.

    1978-01-01

    The isotope shift in the lambda = 2537 A line of the even isotopes 206 Hg, 190 Hg, 188 Hg, 186 Hg, 184 Hg as well as of the I = 13/2 isomers of 191 Hg, 189 Hg, 187 Hg, 185 Hg has been measured by use of a tunable dye laser at the on-line masseparator ISOLDE at CERN. The resulting delta 2 > values follow the line, extrapolated from the chain 205 Hg- 187 Hg which is known to have spherical nuclear shape at the heavy end changing smoothly to slight oblate deformation for the lighter isotopes. Previous measurements of the I = 1/2 groundstates of 181 Hg. 183 Hg and 185 Hg revealed a sharp shape transition to strong deformation. Combined with the new results the following effects can be proved for the first time from the model-independent quantity delta 2 >: 1) the existence of odd even-shape staggering, 2) the coexistence of very different shapes in one and the same nucleus as manifested by the huge isomer shift in 185 Hg, 3) the absence of mixing of the different shapes. (author)

  10. Simulating dam-break over an erodible embankment using SWE-Exner model and semi-implicit staggered scheme

    Science.gov (United States)

    Ambara, M. D.; Gunawan, P. H.

    2018-03-01

    The impact of a dam-break wave on an erodible embankment with a steep slope has been studied recently using both experimental and numerical approaches. In this paper, the semi-implicit staggered scheme for approximating the shallow water-Exner model will be elaborated to describe the erodible sediment on a steep slope. This scheme is known as a robust scheme to approximate shallow water-Exner model. The results are shown in a good agreement with the experimental data. The comparisons of numerical results with data experiment using slopes Φ = 59.04 and Φ = 41.42 by coefficient of Grass formula Ag = 2 × 10‑5 and Ag = 10‑5 respectively are found the closest results to the experiment. This paper can be seen as the additional validation of semi-implicit staggered scheme in the paper of Gunawan, et al (2015).

  11. Tight-binding electrons on triangular and kagome lattices under staggered modulated magnetic fields: quantum Hall effects and Hofstadter butterflies

    Energy Technology Data Exchange (ETDEWEB)

    Li Juan; Wang Yifei; Gong Changde, E-mail: yfwang_nju@hotmail.com [Center for Statistical and Theoretical Condensed Matter Physics, and Department of Physics, Zhejiang Normal University, Jinhua 321004 (China)

    2011-04-20

    We consider the tight-binding models of electrons on a two-dimensional triangular lattice and kagome lattice under staggered modulated magnetic fields. Such fields have two components: a uniform-flux part with strength {phi}, and a staggered-flux part with strength {Delta}{phi}. Various properties of the Hall conductances and Hofstadter butterflies are studied. When {phi} is fixed, variation of {Delta}{phi} leads to the quantum Hall transitions and Chern numbers of Landau subbands being redistributed between neighboring pairs. The energy spectra with nonzero {Delta}{phi}s have similar fractal structures but quite different energy gaps compared with the original Hofstadter butterflies of {Delta}{phi} = 0. Moreover, the fan-like structure of Landau levels in the low magnetic field region is also modified appreciably by {Delta}{phi}.

  12. Hydrogen bonds and van der Waals forces as tools for the construction of a herringbone pattern in the crystal structure of hexane-1,6-diaminium hexane-1,6-diyl bis(hydrogen phosphonate

    Directory of Open Access Journals (Sweden)

    Guido J. Reiss

    2017-01-01

    Full Text Available The asymmetric unit of the title salt, [H3N(CH26NH3][(HOO2P(CH26PO2(OH], consists of one half of a hexane-1,6-diaminium dication and one half of a hexane-1,6-diyl bis(hydrogen phosphonate dianion. Both are located around different centres of inversion (Wyckoff sites: 2a and 2d of the space group P21/c. The shape of the hexane-1,6-diaminium cation is best described as a double hook. Both aminium groups as well as the two attached CH2 groups are turned out from the plane of the central four C atoms. In contrast, all six C atoms of the dianion are almost in a plane. The hydrogen phosphonate (–PO3H groups of the anions and the aminium groups of the cations form two-dimensional O—H... and O—H...N hydrogen-bonded networks parallel to the ac plane, built up from ten-membered and twelve-membered ring motifs with graph-set descriptors R33(10 and R54(12, respectively. These networks are linked by the alkylene chains of the anions and cations. The resulting three-dimensional network shows a herringbone pattern, which resembles the parent structures 1,6-diaminohexane and hexane-1,6-diphosphonic acid.

  13. Postprandial effects of consuming a staggered meal on gut peptide and glycemic responses in obese women and men.

    Science.gov (United States)

    Griffith, Lisa; Haddad, Ella H; Tonstad, Serena

    2016-01-01

    Eating slowly by staggering a meal may reduce energy intake. Our aim was to examine the effect of eating a portion of beans 15min before the rest of the meal, on gastrointestinal (GI) peptides, glucose and insulin concentrations and subsequent energy intake in obese adults. This was a randomised crossover design study with 28 obese subjects. Participants consumed a standardised breakfast on test days followed by test meals: (1) control meal containing 86g (0.5 cup) of beans, and (2) staggered meal in which 86g (0.5 cup) of beans were consumed 15min before the rest of the meal. Blood obtained prior to and at 30, 60, and 120min following the meals was analysed for acylated ghrelin, unacylated ghrelin, glucagon-like peptide-1 (GLP-1), peptide YY, oxyntomodulin, glucose and insulin. Feelings of hunger and satiety were assessed using analog visual scales. Energy intake following the test meal was obtained by computer assisted dietary recalls. Mixed model statistical analysis of data showed time effects for unacylated ghrelin, GLP-1, glucose, insulin, hunger and fullness, however, meal effects were not shown for any of the parameters. GLP-1 area under the curve from baseline to 120min (AUC0-120) decreased by 19% (P=0.024) and that of glucose increased by 7% (P=0.046) following the staggered compared to the control bean meal. Energy intake subsequent to the test meals did not differ between treatments. In conclusion, lengthening meal times by staggering eating did not benefit hormonal, metabolic or appetite control in obese individuals. Copyright © 2015 Asia Oceania Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.

  14. JIGSAW-GEO (1.0): locally orthogonal staggered unstructured grid generation for general circulation modelling on the sphere

    Science.gov (United States)

    Engwirda, Darren

    2017-06-01

    An algorithm for the generation of non-uniform, locally orthogonal staggered unstructured spheroidal grids is described. This technique is designed to generate very high-quality staggered Voronoi-Delaunay meshes appropriate for general circulation modelling on the sphere, including applications to atmospheric simulation, ocean-modelling and numerical weather prediction. Using a recently developed Frontal-Delaunay refinement technique, a method for the construction of high-quality unstructured spheroidal Delaunay triangulations is introduced. A locally orthogonal polygonal grid, derived from the associated Voronoi diagram, is computed as the staggered dual. It is shown that use of the Frontal-Delaunay refinement technique allows for the generation of very high-quality unstructured triangulations, satisfying a priori bounds on element size and shape. Grid quality is further improved through the application of hill-climbing-type optimisation techniques. Overall, the algorithm is shown to produce grids with very high element quality and smooth grading characteristics, while imposing relatively low computational expense. A selection of uniform and non-uniform spheroidal grids appropriate for high-resolution, multi-scale general circulation modelling are presented. These grids are shown to satisfy the geometric constraints associated with contemporary unstructured C-grid-type finite-volume models, including the Model for Prediction Across Scales (MPAS-O). The use of user-defined mesh-spacing functions to generate smoothly graded, non-uniform grids for multi-resolution-type studies is discussed in detail.

  15. Development of multi dimensional analysis code for containment safety and performance based on staggered semi-implicit finite volume method

    International Nuclear Information System (INIS)

    Hong, Soon Joon; Hwang, Su Hyun; Han, Tae Young; Lee, Byung Chul; Byun, Choong Sup

    2009-01-01

    A solver of 3-dimensional thermal hydraulic analysis code for a large building having multi rooms such as reactor containment was developed based on 2-phase and 3-field conservation equations. Three fields mean gas, continuous liquid, and dispersed drop. Gas field includes steam, air and hydrogen. Gas motion equation and state equation also considered. Homogeneous and equilibrium conditions were assumed for gas motion equation. Source terms related with phase change were explicitly expressed for the implicit scheme. Resultantly, total 17 independent equations were setup, and total 17 primitive unknowns were identified. Numerical scheme followed the FVM (Finite Volume Method) based on staggered orthogonal structured grid and semi-implicit method. Staggered grid system produces staggered numerical cells of a scalar cell and a vector cell. The porosity method was adopted for easy handling the complex structures inside a computational cell. Such porosity method has been known to be very effective in reducing mesh numbers and acquiring accurate results in spite of fewer meshes. In the actual programming C++ language of OOP (Object Oriented Programming) was used. The code developed by OOP has the features such as the information hiding, encapsulation, modularity and inheritance. These can offer code developers the more explicit and clearer development method. Classes were designed. Cell and Face, and Volume and Component are the bases of the largest Class, System. Class Solver was designed in order to run the solver. Sample runs showed physically reasonable results. The foundation of code was setup through a series of numerical development. (author)

  16. Entropy Stable Staggered Grid Discontinuous Spectral Collocation Methods of any Order for the Compressible Navier--Stokes Equations

    KAUST Repository

    Parsani, Matteo

    2016-10-04

    Staggered grid, entropy stable discontinuous spectral collocation operators of any order are developed for the compressible Euler and Navier--Stokes equations on unstructured hexahedral elements. This generalization of previous entropy stable spectral collocation work [M. H. Carpenter, T. C. Fisher, E. J. Nielsen, and S. H. Frankel, SIAM J. Sci. Comput., 36 (2014), pp. B835--B867, M. Parsani, M. H. Carpenter, and E. J. Nielsen, J. Comput. Phys., 292 (2015), pp. 88--113], extends the applicable set of points from tensor product, Legendre--Gauss--Lobatto (LGL), to a combination of tensor product Legendre--Gauss (LG) and LGL points. The new semidiscrete operators discretely conserve mass, momentum, energy, and satisfy a mathematical entropy inequality for the compressible Navier--Stokes equations in three spatial dimensions. They are valid for smooth as well as discontinuous flows. The staggered LG and conventional LGL point formulations are compared on several challenging test problems. The staggered LG operators are significantly more accurate, although more costly from a theoretical point of view. The LG and LGL operators exhibit similar robustness, as is demonstrated using test problems known to be problematic for operators that lack a nonlinear stability proof for the compressible Navier--Stokes equations (e.g., discontinuous Galerkin, spectral difference, or flux reconstruction operators).

  17. Research of heat transfer of staggered horizontal bundles of finned tubes at free air convection

    Science.gov (United States)

    Novozhilova, A. V.; Maryna, Z. G.; Samorodov, A. V.; Lvov, E. A.

    2017-11-01

    The study of free-convective processes is important because of the cooling problem in many machines and systems, where other ways of cooling are impossible or impractical. Natural convective processes are common in the steam turbine air condensers of electric power plants located within the city limits, in dry cooling towers of circulating water systems, in condensers cooled by air and water, in radiators cooling oil of power electric transformers, in emergency cooling systems of nuclear reactors, in solar power, as well as in air-cooling of power semiconductor energy converters. All this makes actual the synthesis of the results of theoretical and experimental research of free convection for heat exchangers with finned tube bundles. The results of the study of free-convection heat transfer for two-, three- and four-row staggered horizontal bundles of industrial bimetallic finned tubes with finning factor of 16.8 and equilateral tubes arrangement are presented. Cross and diagonal steps in the bundles are the same: 58; 61; 64; 70; 76; 86; 100 mm, which corresponds to the relative steps: 1.042; 1.096; 1.152; 1.258; 1.366; 1.545; 1.797. These steps are standardized for air coolers. An equation for calculating the free-convection heat transfer, taking into account the influence of geometrical parameters in the range of Rayleigh number from 30,000 to 350,000 with an average deviation of ± 4.8%, has been obtained. The relationship presented in the article allows designing a wide range of air coolers for various applications, working in the free convection modes.

  18. Heat exchange and pressure drop of herring-bone fin surfaces. Experimental cell results at constant wall temperature; Echange de chaleur et perte de charge de surfaces a ailettes en chevrons. Resultats experimentaux en cellule a temperature de paroi constante

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1968-07-01

    The increase in the specific power of nuclear reactors of the gas-graphite type has necessitated the use of high performance exchange surfaces for canning the fuel (natural uranium). For this, experiments were carried out on cans fitted with herring-bone fins, at constant wall temperature; a flow of water at 100 deg. C passes inside the can which is cooled externally by a flow of CO{sub 2} at 15 bars pressure. This experimental set-up makes it possible to compare the aero-thermal performances of the different cans with an accuracy of 5 per cent. This report presents the results obtained in the form of a friction coefficient f{sub 0} and mean Margoulis number m{sub 0} as a function of the Reynolds number Re{sub 0}, this latter varying from 3 x 10{sup 5} to 9 x 10{sup 5}. (authors) [French] L'augmentation de la puissance specifique des reacteurs nucleaires de la filiere graphite-gaz a necessite l'utilisation de surfaces d'echange a hautes performances pour gainer le combustible (uranium naturel). Dans cette optique, des gaines munies d'ailettes disposees en chevron ont ete experimentees a temperature de paroi constante: un courant d'eau a 100 deg. C circule a l'interieur de la gaine qui est refroidie exterieurement par un ecoulement de CO{sub 2} sous une pression de 15 bars. Cette methode experimentale permet de situer les performances aerothermiques des gaines les unes par rapport aux autres a 5 pour cent pres. Ce rapport presente les resultats obtenus sous la forme d'un coefficient de frottement f{sub 0} et d'un nombre de Margoulis moyen m{sub 0} en fonction du nombre de Reynolds Re{sub 0}, ce dernier pouvant varier de 3. 10{sup 5} a 9. 10{sup 5}. (auteurs)

  19. 3D Staggered-Grid Finite-Difference Simulation of Acoustic Waves in Turbulent Moving Media

    Science.gov (United States)

    Symons, N. P.; Aldridge, D. F.; Marlin, D.; Wilson, D. K.; Sullivan, P.; Ostashev, V.

    2003-12-01

    Acoustic wave propagation in a three-dimensional heterogeneous moving atmosphere is accurately simulated with a numerical algorithm recently developed under the DOD Common High Performance Computing Software Support Initiative (CHSSI). Sound waves within such a dynamic environment are mathematically described by a set of four, coupled, first-order partial differential equations governing small-amplitude fluctuations in pressure and particle velocity. The system is rigorously derived from fundamental principles of continuum mechanics, ideal-fluid constitutive relations, and reasonable assumptions that the ambient atmospheric motion is adiabatic and divergence-free. An explicit, time-domain, finite-difference (FD) numerical scheme is used to solve the system for both pressure and particle velocity wavefields. The atmosphere is characterized by 3D gridded models of sound speed, mass density, and the three components of the wind velocity vector. Dependent variables are stored on staggered spatial and temporal grids, and centered FD operators possess 2nd-order and 4th-order space/time accuracy. Accurate sound wave simulation is achieved provided grid intervals are chosen appropriately. The gridding must be fine enough to reduce numerical dispersion artifacts to an acceptable level and maintain stability. The algorithm is designed to execute on parallel computational platforms by utilizing a spatial domain-decomposition strategy. Currently, the algorithm has been validated on four different computational platforms, and parallel scalability of approximately 85% has been demonstrated. Comparisons with analytic solutions for uniform and vertically stratified wind models indicate that the FD algorithm generates accurate results with either a vanishing pressure or vanishing vertical-particle velocity boundary condition. Simulations are performed using a kinematic turbulence wind profile developed with the quasi-wavelet method. In addition, preliminary results are presented

  20. Dual-mixed finite elements for the three-field Stokes model as a finite volume method on staggered grids

    KAUST Repository

    Kou, Jisheng

    2017-06-09

    In this paper, a new three-field weak formulation for Stokes problems is developed, and from this, a dual-mixed finite element method is proposed on a rectangular mesh. In the proposed mixed methods, the components of stress tensor are approximated by piecewise constant functions or Q1 functions, while the velocity and pressure are discretized by the lowest-order Raviart-Thomas element and the piecewise constant functions, respectively. Using quadrature rules, we demonstrate that this scheme can be reduced into a finite volume method on staggered grid, which is extensively used in computational fluid mechanics and engineering.

  1. Heat transfer of a staggered fining flat-oval tube banks in cross flow at the small Reynolds number

    Directory of Open Access Journals (Sweden)

    Максим Михайлович Вознюк

    2015-05-01

    Full Text Available Experimental investigations of heat transfer of staggered bundles of flat-oval tubes with incomplete transversal finning in the range of Reynolds numbers 500 < <20000 are performed. New calculation correlations for determining of heat transfer coefficients for 1<3000 are suggested, the impact of basic geometric and regime parameters on intensity of external heat transfer are determined. The received calculation depending is possible to use in developing of heat transfer surfaces for “dry” cooling towers and air cooling apparatuses

  2. Effects of Front-Loading and Stagger Angle on Endwall Losses of High Lift Low Pressure Turbine Vanes

    Science.gov (United States)

    2012-09-01

    length scale at z/H = 0.20 ………….… 131 Fig. E.1 Traverse arrangement to enable 3D movement inside the wind tunnel …..… 132 Fig. E.2 Diagram of in...2 ] USAF = United States Air Force 2D = two-dimensional 3D = three-dimensional 1 EFFECTS OF FRONT-LOADING AND STAGGER ANGLE ON ENDWALL...within the wakes. I used Druck LPM 5481 pressure transducers, calibrated using a Ruska 7250LP laboratory standard (the reported accuracy is within

  3. Three-dimensional viscoelastic time-domain finite-difference seismic modelling using the staggered Adams-Bashforth time integrator

    Science.gov (United States)

    Bohlen, Thomas; Wittkamp, Florian

    2016-03-01

    We analyse the performance of a higher order accurate staggered viscoelastic time-domain finite-difference method, in which the staggered Adams-Bashforth (ABS) third-order and fourth-order accurate time integrators are used for temporal discretization. ABS is a multistep method that uses previously calculated wavefields to increase the order of accuracy in time. The analysis shows that the numerical dispersion is much lower than that of the widely used second-order leapfrog method. Numerical dissipation is introduced by the ABS method which is significantly smaller for fourth-order than third-order accuracy. In 1-D and 3-D simulation experiments, we verify the convincing improvements of simulation accuracy of the fourth-order ABS method. In a realistic elastic 3-D scenario, the computing time reduces by a factor of approximately 2.4, whereas the memory requirements increase by approximately a factor of 2.2. The ABS method thus provides an alternative strategy to increase the simulation accuracy in time by investing computer memory instead of computing time.

  4. Joint Interference Alignment and Power Allocation for K-User Multicell MIMO Channel through Staggered Antenna Switching.

    Science.gov (United States)

    Selvaprabhu, Poongundran; Chinnadurai, Sunil; Sarker, Md Abdul Latif; Lee, Moon Ho

    2018-01-28

    In this paper, we characterise the joint interference alignment (IA) and power allocation strategies for a K -user multicell multiple-input multiple-output (MIMO) Gaussian interference channel. We consider a MIMO interference channel with blind-IA through staggered antenna switching on the receiver. We explore the power allocation and feasibility condition for cooperative cell-edge (CE) mobile users (MUs) by assuming that the channel state information is unknown. The new insight behind the transmission strategy of the proposed scheme is premeditated (randomly generated transmission strategy) and partial cooperative CE MUs, where the transmitter is equipped with a conventional antenna, the receiver is equipped with a reconfigurable multimode antenna (staggered antenna switching pattern), and the receiver switches between preset T modes. Our proposed scheme assists and aligns the desired signals and interference signals to cancel the common interference signals because the received signal must have a corresponding independent signal subspace. The capacity for a K -user multicell MIMO Gaussian interference channel with reconfigurable multimode antennas is completely characterised. Furthermore, we show that the proposed K -user multicell MIMO scheduling and K -user L -cell CEUs partial cooperation algorithms elaborate the generalisation of K -user IA and power allocation strategies. The numerical results demonstrate that the proposed intercell interference scheme with partial-cooperative CE MUs achieves better capacity and signal-to-interference plus noise ratio (SINR) performance compared to noncooperative CE MUs and without intercell interference schemes.

  5. Joint Interference Alignment and Power Allocation for K-User Multicell MIMO Channel through Staggered Antenna Switching

    Directory of Open Access Journals (Sweden)

    Poongundran Selvaprabhu

    2018-01-01

    Full Text Available In this paper, we characterise the joint interference alignment (IA and power allocation strategies for a K-user multicell multiple-input multiple-output (MIMO Gaussian interference channel. We consider a MIMO interference channel with blind-IA through staggered antenna switching on the receiver. We explore the power allocation and feasibility condition for cooperative cell-edge (CE mobile users (MUs by assuming that the channel state information is unknown. The new insight behind the transmission strategy of the proposed scheme is premeditated (randomly generated transmission strategy and partial cooperative CE MUs, where the transmitter is equipped with a conventional antenna, the receiver is equipped with a reconfigurable multimode antenna (staggered antenna switching pattern, and the receiver switches between preset T modes. Our proposed scheme assists and aligns the desired signals and interference signals to cancel the common interference signals because the received signal must have a corresponding independent signal subspace. The capacity for a K-user multicell MIMO Gaussian interference channel with reconfigurable multimode antennas is completely characterised. Furthermore, we show that the proposed K-user multicell MIMO scheduling and K-user L-cell CEUs partial cooperation algorithms elaborate the generalisation of K-user IA and power allocation strategies. The numerical results demonstrate that the proposed intercell interference scheme with partial-cooperative CE MUs achieves better capacity and signal-to-interference plus noise ratio (SINR performance compared to noncooperative CE MUs and without intercell interference schemes.

  6. Risk-based decision making for staggered bioterrorist attacks : resource allocation and risk reduction in "reload" scenarios.

    Energy Technology Data Exchange (ETDEWEB)

    Lemaster, Michelle Nicole; Gay, David M. (Sandia National Laboratories, Albuquerque, NM); Ehlen, Mark Andrew (Sandia National Laboratories, Albuquerque, NM); Boggs, Paul T.; Ray, Jaideep

    2009-10-01

    Staggered bioterrorist attacks with aerosolized pathogens on population centers present a formidable challenge to resource allocation and response planning. The response and planning will commence immediately after the detection of the first attack and with no or little information of the second attack. In this report, we outline a method by which resource allocation may be performed. It involves probabilistic reconstruction of the bioterrorist attack from partial observations of the outbreak, followed by an optimization-under-uncertainty approach to perform resource allocations. We consider both single-site and time-staggered multi-site attacks (i.e., a reload scenario) under conditions when resources (personnel and equipment which are difficult to gather and transport) are insufficient. Both communicable (plague) and non-communicable diseases (anthrax) are addressed, and we also consider cases when the data, the time-series of people reporting with symptoms, are confounded with a reporting delay. We demonstrate how our approach develops allocations profiles that have the potential to reduce the probability of an extremely adverse outcome in exchange for a more certain, but less adverse outcome. We explore the effect of placing limits on daily allocations. Further, since our method is data-driven, the resource allocation progressively improves as more data becomes available.

  7. SBP-SAT finite difference discretization of acoustic wave equations on staggered block-wise uniform grids

    KAUST Repository

    Gao, Longfei

    2018-02-16

    We consider the numerical simulation of the acoustic wave equations arising from seismic applications, for which staggered grid finite difference methods are popular choices due to their simplicity and efficiency. We relax the uniform grid restriction on finite difference methods and allow the grids to be block-wise uniform with nonconforming interfaces. In doing so, variations in the wave speeds of the subterranean media can be accounted for more efficiently. Staggered grid finite difference operators satisfying the summation-by-parts (SBP) property are devised to approximate the spatial derivatives appearing in the acoustic wave equation. These operators are applied within each block independently. The coupling between blocks is achieved through simultaneous approximation terms (SATs), which impose the interface condition weakly, i.e., by penalty. Ratio of the grid spacing of neighboring blocks is allowed to be rational number, for which specially designed interpolation formulas are presented. These interpolation formulas constitute key pieces of the simultaneous approximation terms. The overall discretization is shown to be energy-conserving and examined on test cases of both theoretical and practical interests, delivering accurate and stable simulation results.

  8. An experimental study on the effect of wind load around tall towers of square and hexagonal shapes in staggered form

    Science.gov (United States)

    Anwar, Proma; Islam, Md. Quamrul; Ali, Mohammad

    2017-06-01

    In this research work an experiment is conducted to observe the effect of wind load around square and hexagonal shaped cylinders in staggered form. The experiment is performed in an open circuit wind tunnel at a Reynolds number of 4.23×104 based on the face width of the cylinder across the flow direction. The flow velocity has been kept uniform at 14.3 m/s throughout the experiment. The test is conducted for single cylinders first and then in staggered form. The cylinders are rotated to create different angles of attack and the angles are chosen at a definite interval. The static pressure readings are taken at different locations of the cylinder by inclined multi-manometers. From the surface static pressure readings pressure coefficients, drag coefficients and lift coefficients are calculated using numerical integration method. These results will surely help engineers to design buildings more stable against wind load. All the results are expressed in non-dimensional form, so that they can be applied for prototype structures.

  9. Isospin transport phenomena and odd-even staggering in 84Kr+112,124Sn collisions at 35 AMeV

    Directory of Open Access Journals (Sweden)

    Piantelli S.

    2015-01-01

    Full Text Available Experimental results concerning isospin transport phenomena and odd-even staggering in Z and N distributions are presented. Data refer to 84Kr+112,124Sn collisions at 35AMeV and they were collected with a high resolution FAZIA telescope, able to isotopically resolve ions up to Z ∼ 20. Evidences of isospin diffusion and drift obtained from the /Z behaviour of the detected fragments are discussed. The odd-even staggering both in Z and N is compared with experimental data available in literature, finding that it shows a common trend in different reaction types.

  10. Isospin transport phenomena and odd-even staggering in 84Kr+112,124Sn collisions at 35 AMeV

    Science.gov (United States)

    Piantelli, S.; Casini, G.; Maurenzig, P. R.; Olmi, A.; Barlini, S.; Bini, M.; Carboni, S.; Pasquali, G.; Poggi, G.; Stefanini, A. A.; Valdré, S.; Bougault, R.; Bonnet, E.; Borderie, B.; Chbihi, A.; Frankland, J. D.; Gruyer, D.; Lopez, O.; Le Neindre, N.; Parlog, M.; Rivet, M.-F.; Vient, E.; Rosato, E.; Spadaccini, G.; Vigilante, M.; Bruno, M.; Marchi, T.; Morelli, L.; Cinausero, M.; Degerlier, M.; Gramegna, F.; Kozik, T.; Twarog, T.; Alba, R.; Maiolino, C.; Santonocito, D.

    2015-04-01

    Experimental results concerning isospin transport phenomena and odd-even staggering in Z and N distributions are presented. Data refer to 84Kr+112,124Sn collisions at 35AMeV and they were collected with a high resolution FAZIA telescope, able to isotopically resolve ions up to Z ˜ 20. Evidences of isospin diffusion and drift obtained from the /Z behaviour of the detected fragments are discussed. The odd-even staggering both in Z and N is compared with experimental data available in literature, finding that it shows a common trend in different reaction types.

  11. Staggered-grid finite-difference acoustic modeling with the Time-Domain Atmospheric Acoustic Propagation Suite (TDAAPS).

    Energy Technology Data Exchange (ETDEWEB)

    Aldridge, David Franklin; Collier, Sandra L. (U.S. Army Research Laboratory); Marlin, David H. (U.S. Army Research Laboratory); Ostashev, Vladimir E. (NOAA/Environmental Technology Laboratory); Symons, Neill Phillip; Wilson, D. Keith (U.S. Army Cold Regions Research Engineering Lab.)

    2005-05-01

    This document is intended to serve as a users guide for the time-domain atmospheric acoustic propagation suite (TDAAPS) program developed as part of the Department of Defense High-Performance Modernization Office (HPCMP) Common High-Performance Computing Scalable Software Initiative (CHSSI). TDAAPS performs staggered-grid finite-difference modeling of the acoustic velocity-pressure system with the incorporation of spatially inhomogeneous winds. Wherever practical the control structure of the codes are written in C++ using an object oriented design. Sections of code where a large number of calculations are required are written in C or F77 in order to enable better compiler optimization of these sections. The TDAAPS program conforms to a UNIX style calling interface. Most of the actions of the codes are controlled by adding flags to the invoking command line. This document presents a large number of examples and provides new users with the necessary background to perform acoustic modeling with TDAAPS.

  12. Investigating the iatrogenic effects of repeated suicidal ideation screening on suicidal and depression symptoms: A staggered sequential study.

    Science.gov (United States)

    Hom, Melanie A; Stanley, Ian H; Rogers, Megan L; Gallyer, Austin J; Dougherty, Sean P; Davis, Lisa; Joiner, Thomas E

    2018-02-21

    Research suggests that screening for suicidality does not have iatrogenic effects; however, less is known regarding the impact of repeatedly screening for suicidal ideation among individuals with varying levels of exposure to these screenings. This staggered sequential study evaluated whether suicidal ideation severity increases with repeated screening for suicidal ideation and depression symptoms. Undergraduates (N = 207) were recruited at one of four time points (baseline [n = 37], 1 month later [n = 61], 4 months later [n = 55], and 12 months later [n = 54]) to complete the self-report Beck Depression Inventory (BDI). Participants completed the BDI at the time point at which they were recruited and all subsequent study time points. Non-parametric tests were employed to compare suicidal ideation severity (BDI Item 9) and depression symptom severity (BDI total score): (1) within each group across time points and (2) within each time point across groups. Suicidal ideation severity did not significantly differ within any group across time points, and for two groups, depression symptom severity decreased over time. For analyses between groups, suicidal ideation and depression symptom scores were, at times, significantly lower during subsequent BDI completion time points. This study utilized a relatively small sample size and participants of low clinical severity. Findings align with prior research indicating that suicidality screening is not iatrogenic. This study also expanded upon previous studies by leveraging a staggered sequential design to compare suicidal ideation and depression symptom severity among individuals with varying exposure to suicidal ideation screenings. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Towards the development of a fully coupled arterial-venous 1D model: suitability of using a 1D finite volume method with staggered spatial discretization

    CSIR Research Space (South Africa)

    Bogaers, Alfred EJ

    2012-07-01

    Full Text Available In this paper we outline the development of a 1D finite volume model to solve for blood flow through the arterial system. The model is based on a staggered spatial discretization which leads to a stable solution scheme. This scheme can accurately...

  14. 49 CFR Figure 1 to Subpart B of... - Example of Location and Staggering of Emergency Window Exits-§ 238.113

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Example of Location and Staggering of Emergency Window Exits-§ 238.113 1 Figure 1 to Subpart B of Part 238 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PASSENGER EQUIPMENT...

  15. 49 CFR Figure 2 to Subpart B of... - Example of a Multi-Level Car Complying with Window Location and Staggering Requirements-§§ 238...

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Example of a Multi-Level Car Complying with Window Location and Staggering Requirements-§§ 238.113 and 238.114 2 Figure 2 to Subpart B of Part 238 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...

  16. 29 CFR Appendix H to Subpart R of... - Double Connections: Illustration of a Clipped End Connection and a Staggered Connection: Non...

    Science.gov (United States)

    2010-07-01

    ... Connection and a Staggered Connection: Non-Mandatory Guidelines for Complying With § 1926.756(c)(1) H Appendix H to Subpart R of Part 1926 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY... CONSTRUCTION Steel Erection Pt. 1926, Subpt. R, App. H Appendix H to Subpart R of Part 1926—Double Connections...

  17. Statin prescribing for people with severe mental illnesses: a staggered cohort study of 'real-world' impacts.

    Science.gov (United States)

    Blackburn, R; Osborn, D; Walters, K; Falcaro, M; Nazareth, I; Petersen, I

    2017-03-07

    To estimate the 'real-world effectiveness of statins for primary prevention of cardiovascular disease (CVD) and for lipid modification in people with severe mental illnesses (SMI), including schizophrenia and bipolar disorder. Series of staggered cohorts. We estimated the effect of statin prescribing on CVD outcomes using a multivariable Poisson regression model or linear regression for cholesterol outcomes. 587 general practice (GP) surgeries across the UK reporting data to The Health Improvement Network. All permanently registered GP patients aged 40-84 years between 2002 and 2012 who had a diagnosis of SMI. Exclusion criteria were pre-existing CVD, statin-contraindicating conditions or a statin prescription within the 24 months prior to the study start. One or more statin prescriptions during a 24-month 'baseline' period (vs no statin prescription during the same period). The primary outcome was combined first myocardial infarction and stroke. All-cause mortality and total cholesterol concentration were secondary outcomes. We identified 2944 statin users and 42 886 statin non-users across the staggered cohorts. Statin prescribing was not associated with significant reduction in CVD events (incident rate ratio 0.89; 95% CI 0.68 to 1.15) or all-cause mortality (0.89; 95% CI 0.78 to 1.02). Statin prescribing was, however, associated with statistically significant reductions in total cholesterol of 1.2 mmol/L (95% CI 1.1 to 1.3) for up to 2 years after adjusting for differences in baseline characteristics. On average, total cholesterol decreased from 6.3 to 4.6 in statin users and 5.4 to 5.3 mmol/L in non-users. We found that statin prescribing to people with SMI in UK primary care was effective for lipid modification but not CVD events. The latter finding may reflect insufficient power to detect a smaller effect size than that observed in randomised controlled trials of statins in people without SMI. Published by the BMJ Publishing Group Limited. For

  18. Theoretical and experimental study of heat transfers and pressure drops along surfaces fitted with herring-bone fins: correlation between geometric and aero thermal parameters; Etudes theorique et experimentale du transfert de chaleur et des pertes de charge de surfaces munies d'ailettes disposees en chevron - correlation entre parametres geometriques et aerothermiques

    Energy Technology Data Exchange (ETDEWEB)

    Pelce, J.; Malherbe, J.; Pierre, B. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    Principal results are given of experimental research which has been carried out on the flow of a fluid along a surface fitted with herringbone fins. Aero-thermal tests have been effected on a large number of these surfaces whose geometrical parameters have been made to vary systematically. In particular, work on a large scale model has made it possible to analyse the mechanisms of heat transfer and of pressure drops. On this basis a theoretical study has led to the establishment of a correlation between the geometric configuration and the aero-thermal performances of these surfaces. Experimental results are in good agreement with the theoretical relationships. An expression has thus been derived applicable to this type of herring-boned surface in a wide zone. (authors) [French] L'ecoulement d'un fluide au voisinage d'une surface munie d'ailettes disposees en chevron a fait l'objet de recherches experimentales dont on a rappele les principaux resultats. Des essais aerothermiques ont ete effectues sur un grand nombre de ces surfaces dont a fait varier les parametres geometriques de facon systematique. En particulier, des etudes sur une maquette a grande echelle ont permis d'analyser les mecanismes de transfert de chaleur et de perte de charge. Sur ces bases, une etude theorique a conduit a des correlations entre la geometrie et les performances aerothermiques de ces surfaces. Les resultats experimentaux sont en bon accord avec les relations theoriques. On possede ainsi une formulation pour ce type de surface ailettee valable dans un domaine etendu. (auteurs)

  19. Periodically fully developed laminar flow and heat transfer in a two-dimensional horizontal channel with staggered fins

    Directory of Open Access Journals (Sweden)

    Turgut Oğuz

    2017-01-01

    Full Text Available The 2-D periodically fully developed laminar forced convection fluid flow and heat transfer characteristics in a horizontal channel with staggered fins are investigated numerically under constant wall heat flux boundary condition. Study is performed using ANSYS Fluent 6.3.26 which uses finite volume method. Air (Pr @ 0.7 and Freon-12 (Pr @ 3.5 are used as working fluids. Effects of Reynolds number, Prandtl number, fin height, and distances between two fins on heat transfer and friction factor are examined. Results are given in the form of non-dimensional average Nusselt number and average Darcy friction factor as a function of Reynolds number for different fin distances and Prandtl numbers. The velocity and temperature profiles are also obtained. It is seen that as the fin distance increases, behavior approaches the finless channel, as expected. Also, thermal enhancement factors are given graphically for working fluids. It is seen that heat transfer dominates the friction as both the distance between two fins and Prandtl number increase. It is also seen that fins having blockage ratio of 0.10 in 2-D periodically fully developed laminar flow is not advantageous in comparison to smooth channel without fins.

  20. Interim analysis based on the weighted log-rank test for delayed treatment effects under staggered patient entry.

    Science.gov (United States)

    Yoshida, Mizuki; Matsuyama, Yutaka

    2016-01-01

    Fleming and Harrington's G(ρ,γ) class of weighted log-rank tests is appropriate for detecting delayed treatment effects such as those seen in cancer vaccines. A conditional power (CP) and an alpha spending function (ASF) approach are useful for interim analyses that are conducted with the aim of early termination due to futility and efficacy, respectively. However, calculation of the CP and the total Type I error probability are often not considered for delayed effects under the staggered patient entry. In this article, we first propose methods for calculating the CP analytically based on the weighted log-rank test. We compared the performances of the proposed methods with two other methods (i.e., usual log-rank test and optimal one) under the delayed alternatives. Our simulations demonstrated that the CP based on the weighted log-rank test was more powerful than that of the usual log-rank test and was comparable to the CP based on the optimal log-rank test. Second, we quantitatively evaluated the degree to which the Type I error probability was inflated when an ASF approach with forced independent increments assumption was applied to the weighted log-rank test. The proposed method will provide valuable tools in the decision-making stage of the interim analysis.

  1. Localizing gene regulation reveals a staggered wood decay mechanism for the brown rot fungus Postia placenta

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jiwei; Presley, Gerald N.; Hammel, Kenneth E.; Ryu, Jae-San; Menke, Jon R.; Figueroa, Melania; Hu, Dehong; Orr, Galya; Schilling, Jonathan S.

    2016-09-12

    The fungi that cause brown rot of wood are essential contributors to biomass recycling in forest ecosystems. Their highly efficient cellulolytic systems, which may have practical applications, apparently depend on a combination of two mechanisms: nonselective oxidation of the lignocellulose by reactive oxygen species (ROS) coupled with hydrolysis of the polysaccharide components by a limited set of glycoside hydrolases (GHs). Since the production of strongly oxidizing ROS appears incompatible with the operation of GHs, it has been proposed that the fungi regulate ROS production by maintaining concentration gradients of the chelated metal ions they use to generate extracellular oxidants. However, calculations have indicated that this protective mechanism is physically infeasible. We examined a different hypothesis, that expression of ROS and GH components is temporally staggered by brown rot fungi in wood. We sectioned thin wafers of spruce and aspen that had been colonized directionally by Postia placenta and measured expression of relevant genes and some of the encoded enzymes, thus using the spatial distribution of fungal hyphae to resolve a fine-scale temporal sequence. Hierarchical clustering of gene expression for eight oxidoreductases thought to have a role in ROS production and of eight GHs revealed a zone of oxidoreductase upregulation at the hyphal front that persisted about 48 h before upregulation of the GHs. Additional evidence for differential expression was provided by localization of endoglucanase, xylanase, mannanase, and laccase activities in the colonized wood. Our results support a two-step mechanism for brown rot, in which substrate oxidation precedes enzymatic hydrolysis.

  2. Two-fluid mixing in a microchannel

    International Nuclear Information System (INIS)

    Liu Yingzheng; Kim, Byoung Jae; Sung, Hyung Jin

    2004-01-01

    A numerical study of the mixing of two fluids (pure water and a solution of glycerol in water) in a microchannel was carried out. By varying the glycerol content of the glycerol/water solution, the variation in mixing behavior with changes in the difference in the properties of the two fluids (e.g., viscosity, density and diffusivity) was investigated. The mixing phenomena were tested for three micromixers: a squarewave mixer, a three-dimensional serpentine mixer and a staggered herringbone mixer. The governing equations of continuity, momentum and solute mass fraction were solved numerically. To evaluate mixing performance, a criterion index of mixing uniformity was proposed. In the systems considered, the Reynolds number based on averaged properties was Re=1 and 10. For low Reynolds number (Re=1), the mixing performance varied inversely with mass fraction of glycerol due to the dominance of molecular diffusion. The mixing performance deteriorated due to a significant reduction in the residence time of the fluid inside the mixers

  3. Analysis and Optimization of a Novel 2-D Magnet Array with Gaps and Staggers for a Moving-Magnet Planar Motor

    Science.gov (United States)

    Chen, Xuedong; Zeng, Lizhan

    2018-01-01

    This paper presents a novel 2-D magnet array with gaps and staggers, which is especially suitable for magnetically levitated planar motor with moving magnets. The magnetic flux density distribution is derived by Fourier analysis and superposition. The influences of gaps and staggers on high-order harmonics and flux density were analyzed, and the optimized design is presented. Compared with the other improved structures based on traditional Halbach magnet arrays, the proposed design has the lowest high-order harmonics percentage, and the characteristics of flux density meet the demand of high acceleration in horizontal directions. It is also lightweight and easy to manufacture. The proposed magnet array was built, and the calculation results have been verified with experiment. PMID:29300323

  4. On AC-Field-Induced Nonlinear Electroosmosis next to the Sharp Corner-Field-Singularity of Leaky Dielectric Blocks and Its Application in on-Chip Micro-Mixing

    Directory of Open Access Journals (Sweden)

    Yukun Ren

    2018-02-01

    Full Text Available Induced-charge electroosmosis has attracted lots of attention from the microfluidic community over the past decade. Most previous researches on this subject focused on induced-charge electroosmosis (ICEO vortex streaming actuated on ideally polarizable surfaces immersed in electrolyte solutions. Starting from this point, we conduct herein a linear asymptotic analysis on nonlinear electroosmotic flow next to leaky dielectric blocks of arbitrary electrical conductivity and dielectric permittivity in harmonic AC electric fields, and theoretically demonstrate that observable ICEO fluid motion can be generated at high field frequencies in the vicinity of nearly insulating semiconductors, a very low electrical conductivity, of which can evidently increase the double-layer relaxation frequency (inversely proportional to the solid permittivity to be much higher than the typical reciprocal RC time constant for induced double-layer charging on ideally polarizable surfaces. A computational model is developed to study the feasibility of this high-frequency vortex flow field of ICEO for sample mixing in microfluidics, in which the usage of AC voltage signal at high field frequencies may be beneficial to suppress electrochemical reactions to some extent. The influence of various parameters for developing an efficient mixer is investigated, and an integrated arrangement of semiconductor block array is suggested for achieving a reliable mixing performance at relatively high sample fluxes. Our physical demonstration with high-frequency ICEO next to leaky dielectric blocks using a simple channel structure offers valuable insights into the design of high-throughput micromixers for a variety of lab-on-a-chip applications.

  5. Theoretical investigation of GaAsBi/GaAsN tunneling field-effect transistors with type-II staggered tunneling junction

    Science.gov (United States)

    Wang, Yibo; Liu, Yan; Han, Genquan; Wang, Hongjuan; Zhang, Chunfu; Zhang, Jincheng; Hao, Yue

    2017-06-01

    We investigate GaAsBi/GaAsN system for the design of type-II staggered hetero tunneling field-effect transistor (hetero-TFET). Strain-symmetrized GaAsBi/GaAsN with effective lattice match to GaAs exhibits a type-II band lineup, and the effective bandgap EG,eff at interface is significantly reduced with the incorporation of Bi and N elements. The band-to-band tunneling (BTBT) rate and drive current of GaAsBi/GaAsN hetero-TFETs are boosted due to the utilizing of the type-II staggered tunneling junction with the reduced EG,eff. Numerical simulation shows that the drive current and subthreshold swing (SS) characteristics of GaAsBi/GaAsN hetero-TFETs are remarkably improved by increasing Bi and N compositions. The dilute content GaAs0.85Bi0.15/GaAs0.92N0.08 staggered hetero-nTFET achieves 7.8 and 550 times higher ION compared to InAs and In0.53Ga0.47As homo-TFETs, respectively, at the supply voltage of 0.3 V. GaAsBi/GaAsN heterostructure is a potential candidate for high performance TFET.

  6. A Study of the Transient Response of Duct Junctions: Measurements and Gas-Dynamic Modeling with a Staggered Mesh Finite Volume Approach

    Directory of Open Access Journals (Sweden)

    Antonio J. Torregrosa

    2017-05-01

    Full Text Available Duct junctions play a major role in the operation and design of most piping systems. The objective of this paper is to establish the potential of a staggered mesh finite volume model as a way to improve the description of the effect of simple duct junctions on an otherwise one-dimensional flow system, such as the intake or exhaust of an internal combustion engine. Specific experiments have been performed in which different junctions have been characterized as a multi-port, and that have provided precise and reliable results on the propagation of pressure pulses across junctions. The results obtained have been compared to simulations performed with a staggered mesh finite volume method with different flux limiters and different meshes and, as a reference, have also been compared with the results of a more conventional pressure loss-based model. The results indicate that the staggered mesh finite volume model provides a closer description of wave dynamics, even if further work is needed to establish the optimal calculation settings.

  7. A Priori Estimates of Solution of a Homogeneous Boundary Value Problem for Parabolic Type Equations by the Discontinuous Galerkin Method on Staggered Grids

    Directory of Open Access Journals (Sweden)

    Ruslan V. Zhalnin

    2017-12-01

    Full Text Available Introduction: In this paper, we present a priori error analysis of the solution of a homogeneous boundary value problem for a second-order differential equation by the discontinuous Galerkin method on staggered grids. Materials and Methods: This study is based on the unified hp-version error analysis of local discontinuous Galerkin method proposed by Castillo et al. [Optimal a priori error estimates for the hp-version of the local discontinuous Galerkin method for convection-diffusion problems, 2002]. The purpose of this paper is to present a new approach to the error analysis of the solution of parabolic equations by the discontinuous Galerkin method on staggered grids. Results: We suggest that approximation errors depend on the characteristic size of the cells and the degree of polynomials used in the basis functions. The necessary lemmas are formulated for the problem solution. The complete proof of the lemmas formulated is carried out. We formulated and proved a theorem, in which a priori error estimates are given for solving parabolic equations using the discontinuous Galerkin method on staggered grids Discussion and Conclusions: The obtained results are consistent with similar studies of other authors and complement them. Further work on this topic involves the study of diffusion-type equations of order higher than the first and the production of a posteriori error estimates.

  8. A simple and universal ligation mediated fusion of genes based on hetero-staggered PCR for generating immunodominant chimeric proteins.

    Science.gov (United States)

    Reddy, Prakash K; Ramlal, Shylaja; Sripathy, Murali H; Batra, Harshvardhan

    2012-11-01

    We developed a simple T4 DNA ligase mediated strategy for inframe splicing of two or more cohesive genes generated by hetero-staggered PCR and directionally cloning the spliced product bearing sticky overhangs in to a correspondingly cut vector. For this, two pairs of primers are used in two different parallel PCRs, for generation of each cohesive gene product. We exemplified this strategy by splicing two major super-antigen genes of Staphylococcus aureus, namely, staphylococcal enterotoxin A (sea), and toxic shock syndrome toxin (tsst-1) followed by its directional cloning into pre-digested pRSET A vector. The fusion gene encoding chimeric recombinant SEA-TSST protein (32kDa) was expressed in E. coli BL21(DE3) host strain. The recombinant chimeric protein retained the antigenicity of both toxins as observed by the strong immunoreactivity with commercial antibodies against both SEA and TSST-1 toxin components by Western blot analysis. We observed that the present method for gene splicing with cohesive ends is simple since it does not require elaborate standardization and a single fusion product is obtained consistently during nested PCR with forward primer of first gene and reverse primer of second gene. For comparison, we fused the same genes using splicing by overlap extension PCR (SOE-PCR) and consistently obtained DNA smearing and multiple non-specific bands even after several rounds of PCRs from gel excised product. Moreover, the newly described method requires only two to six complimentary sticky ends between the genes to be spliced, in contrast to long stretch of overlapping nucleotides in case of SOE-PCR. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. A Study on the Uncertainty of Flow-Induced Vibration in a Cross Flow over Staggered Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji-Su; Park, Jong-Woon [Dongguk univ, Gyeong Ju (Korea, Republic of); Choi, Hyeon-Kyeong [HanNam University, Daejeon (Korea, Republic of)

    2015-05-15

    Cross-flow in many support columns of very high temperature reactor (VHTR) lower plenum would have FIV issues under high speed flow jetting from the core. For a group of multiple circular cylinders subjected to a cross-flow, three types of potential vibration mechanisms may exist: (1) Vortex-induced vibration (VIV), (2) Fluid-elastic vibration (FEV) and (3) Turbulence-induced vibration (TIV). Kevalahan studied the free vibration of circular cylinders in a tightly packed periodic square inline array of cylinders. Pandey et al. studied the flue gas flow distribution in the Low Temperature Super Heater (LTSH) tube bundles situated in second pass of a utility boiler and the phenomenon of flow induced vibration. Nakamura et al. studied flow instability of cylinder arrays resembling U-bend tubes in steam generators. The FIV evaluation is usually performed with computational fluid dynamic (CFD) analysis to obtain unknown frequency of oscillation of the multiple objects under turbulent flow and thus the uncertainty residing in the turbulence model used should be quantified. In this paper, potential FIV uncertainty arising from the turbulence phenomena are evaluated for a typical cross flow through staggered tube bundles resembling the VHTR lower plenum support columns. Flow induced vibration (FIV) is one of the important mechanical and fatigue issues in nuclear systems. Especially, cross-flow in many support structures of VHTR lower plenum would have FIV issues under highly turbulent jet flows from the core. The results show that the effect of turbulence parameters on FIV is not negligible and the uncertainty is 5 to 10%. Present method can be applied to future FIV evaluations of nuclear systems. More extensive studies on flow induced vibration in a plant scale by using more rigorous computational methods are under way.

  10. Theoretical study of O- and Zn-face polarity effect on the optical properties of the conventional and staggered ZnO/Zn{sub 1−x}Cd{sub x}O/ZnO quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Shtepliuk, I., E-mail: ivan.shtepliuk@liu.se; Khranovskyy, V.; Yakimova, R.

    2015-11-02

    In this work we present a comparative study of Zn-face and O-face polarity Zn{sub 1−x}CdxO-based conventional and staggered quantum-well (QW) structures. The calculation of optical properties of QWs was performed by means of self-consistent Schrodinger–Poisson solver with consideration of polarization-induced effects. The conventional Zn-face and O-face QWs possess similar values of transition energy and an overlap of electron and hole wave functions. A change of the polarity from Zn-face to O-face for the conventional QWs influences only a shape of the conduction and valence band edge profile. It is revealed that the utilization of the staggered QWs leads to an improvement of the confinement characteristics. In addition, the O-face staggered QW structure has larger values of transition energy and overlap integral compared to the Zn-face staggered QW structure. O-terminated staggered QW structure is less dependent on the well thickness and has lower sensitivity to Cd content in embedded Zn{sub 1−x}CdxO layer. Control of the material polarity and design of the staggered QWs provide cost-effective approach for engineering the QW band structures with enhanced QW performance. This enables constructing of the Zn{sub 1−x}CdxO-based light emission diodes with improved radiative efficiency emitting, applicable for solid state lighting. - Highlights: • Effect of polar face on properties of Zn{sub 1−x}Cd{sub x}O quantum wells (QWs) was studied. • O-face staggered QWs were found to possess improved optical properties. • Sensitivity of transition energy to well width was found to be weaker for O-face QW. • Using of the embedded layer in QW reduces quantum confinement Stark effect.

  11. Comparison of the 2nd-order and 4th-order Staggered-Grid Finite-Difference Implementations of the TSN Method for Rupture Propagation

    Science.gov (United States)

    Kristek, J.; Moczo, P.; Galis, M.

    2006-12-01

    The TSN (Traction-at-Split-Nodes) method has been developed independently by Andrews (1973, 1976, 1999) and Day (1977, 1982). Andrews implemented his TSN formulation in the finite-difference scheme in which spatial differentiation is equivalent to the 2nd-order finite-element method. Day implemented his slightly different formulation of the TSN method in the 2nd-order partly-staggered finite-difference scheme. Dalguer and Day (2006) adapted the TSN method to the velocity-stress staggered-grid finite-difference scheme. Whereas the 4th-order spatial differencing is applied outside the fault, the 2nd-order differencing is applied along the fault plane. We present two implementations of the Day's TSN formulation in the velocity-stress staggered-grid finite-difference scheme for a 3D viscoelastic medium. In the first one we apply the 2nd-order spatial differencing everywhere in the grid including derivatives at the fault in the direction perpendicular to the fault plane. In the second implementation we similarly apply the 4th-order spatial differencing. In both cases we use the adjusted finite-difference approximations (AFDA, Kristek et al. 2002, Moczo et al. 2004) to derivatives in the direction perpendicular to the fault plane in order to have the same order of approximation everywhere. We numerically investigate convergence rates of both implementations with respect to rupture-time, final-slip, and peak-slip-rate metrics. Moreover, we compare the numerical solutions to those obtained by the finite-element implementation of the TSN method.

  12. Virological failure of staggered and simultaneous treatment interruption in HIV patients who began Efavirenz-based regimens after allergic reactions to nevirapine

    Directory of Open Access Journals (Sweden)

    Siripassorn Krittaecho

    2013-01-01

    Full Text Available Abstract Objective The objective of this work was to study the virological outcomes associated with two different types of treatment interruption strategies in patients with allergic reactions to nevirapine (NVP. We compared the virological outcomes of (1 HIV-1-infected patients who discontinued an initial NVP-based regimen because of cutaneous allergic reactions to NVP; different types of interruption strategies were used, and second-line regimen was based on efavirenz (EFV; and (2 HIV-1-infected patients who began an EFV-based regimen as a first-line therapy (controls. Methods This retrospective cohort included patients who began an EFV-based regimen, between January 2002 and December 2008, as either an initial regimen or as a subsequent regimen after resolving a cutaneous allergic reaction against an initial NVP-based regimen. The study ended in March 2010. The primary outcome was virological failure, which was defined as either (a two consecutive plasma HIV-1 RNA levels >400 copies/mL or (b a plasma HIV-1 RNA level >1,000 copies/mL plus any genotypic resistance mutation. Results A total of 559 patients were stratified into three groups: (a Simultaneous Interruption, in which the subjects simultaneously discontinued all the drugs in an NVP-based regimen following an allergic reaction (n=161; (b Staggered Interruption, in which the subjects discontinued NVP treatment while continuing nucleoside reverse transcriptase inhibitor (NRTI backbone therapy for a median of 7 days (n=82; and (c Control, in which the subjects were naïve to antiretroviral therapy (n=316. The overall median follow-up time was 43 months. Incidence of virological failure in Simultaneous Interruption was 12.9 cases per 1,000 person-years, which trended toward being higher than the incidences in Staggered Interruption (5.4 and Control (6.6. However, differences were not statistically significant. Conclusions Among the patients who had an acute allergic reaction to first

  13. A representation of curved boundaries for the solution of the Navier-Stokes equations on a staggered three-dimensional Cartesian grid

    International Nuclear Information System (INIS)

    Kirkpatrick, M.P.; Armfield, S.W.; Kent, J.H.

    2003-01-01

    A method is presented for representing curved boundaries for the solution of the Navier-Stokes equations on a non-uniform, staggered, three-dimensional Cartesian grid. The approach involves truncating the Cartesian cells at the boundary surface to create new cells which conform to the shape of the surface. We discuss in some detail the problems unique to the development of a cut cell method on a staggered grid. Methods for calculating the fluxes through the boundary cell faces, for representing pressure forces and for calculating the wall shear stress are derived and it is verified that the new scheme retains second-order accuracy in space. In addition, a novel 'cell-linking' method is developed which overcomes problems associated with the creation of small cells while avoiding the complexities involved with other cell-merging approaches. Techniques are presented for generating the geometric information required for the scheme based on the representation of the boundaries as quadric surfaces. The new method is tested for flow through a channel placed oblique to the grid and flow past a cylinder at Re=40 and is shown to give significant improvement over a staircase boundary formulation. Finally, it is used to calculate unsteady flow past a hemispheric protuberance on a plate at a Reynolds number of 800. Good agreement is obtained with experimental results for this flow

  14. Universal scaling of Néel temperature, staggered magnetization density, and spin-wave velocity of three-dimensional disordered and clean quantum antiferromagnets

    Science.gov (United States)

    Tan, D.-R.; Jiang, F.-J.

    2017-02-01

    The Néel temperature, staggered magnetization density, as well as the spin-wave velocity of a three-dimensional (3D) quantum Heisenberg model with antiferromagnetic disorder (randomness) are calculated using first-principles nonperturbative quantum Monte Carlo simulations. In particular, we examine the validity of universal scaling relations that are related to these three studied physical quantities. These relations are relevant to experimental data and are firmly established for clean (regular) 3D dimerized spin-1/2 Heisenberg models. Remarkably, our numerical results show that the considered scaling relations remain true for the investigated model with the introduced disorder. In addition, while the presence of disorder may change the physical properties of regular dimerized models, hence leading to different critical theories, both the obtained data of Néel temperature and staggered magnetization density in our study are fully compatible with the expected critical behavior for clean dimerized systems. As a result, it is persuasive to conclude that the related quantum phase transitions of the considered disordered model and its clean analogues are governed by the same critical theory, which is not always the case in general. Finally, we also find smooth scaling curves even emerging when both the data of the investigated disordered model as well as its associated clean system are taken into account concurrently. This in turn implies that, while in a restricted sense, the considered scaling relations for 3D spin-1/2 antiferromagnets are indeed universal.

  15. Identical Bands and ΔI=2 Staggering in Superdeformed Nuclei in A~150 Mass Region Using Three Parameters Rotational Model

    Directory of Open Access Journals (Sweden)

    Khalaf A. M.

    2012-10-01

    Full Text Available By using a computer simulated search program, the experimental gamma transition en- ergies for superdeformed rotational bands (SDRB’s in A 150 region are fitted to proposed three-parameters model. The model parameters and the spin of the bandhead were obtained for the selected ten SDRB’s namely: 150 Gd (yrast and excited SD bands, 151 Tb (yrast and excited SD bands, 152 Dy (yrast SD bands, 148 Gd (SD-1,SD-6, 149 Gd (SD-1, 153 Dy (SD-1 and 148 Eu (SD-1. The Kinematic J (1 and dynamic J (2 moments of inertia are studied as a function of the rotational frequency ~ ω . From the calculated results, we notic that the excited SD bands have identical energies to their Z + 1 neigh- bours for the twinned SD bands in N = 86 nuclei. Also the analysis done allows us to confirm Δ I = 2 staggering in the yrast SD bands of 148 Gd, 149 Gd, 153 Dy, and 148 Eu and in the excited SD bands of 148 Gd, by performing a staggering parameter analysis. For each band, we calculated the deviation of the gamma ray energies from smooth ref- erence representing the finite di ff erence approximation to the fourth derivative of the gamma ray transition energies at a given spin.

  16. LaMEM: a Massively Parallel Staggered-Grid Finite-Difference Code for Thermo-Mechanical Modeling of Lithospheric Deformation with Visco-Elasto-Plastic Rheologies

    Science.gov (United States)

    Kaus, B.; Popov, A.

    2014-12-01

    The complexity of lithospheric rheology and the necessity to resolve the deformation patterns near the free surface (faults and folds) sufficiently well places a great demand on a stable and scalable modeling tool that is capable of efficiently handling nonlinearities. Our code LaMEM (Lithosphere and Mantle Evolution Model) is an attempt to satisfy this demand. The code utilizes a stable and numerically inexpensive finite difference discretization with the spatial staggering of velocity, pressure, and temperature unknowns (a so-called staggered grid). As a time discretization method the forward Euler, or a combination of the predictor-corrector and the fourth-order Runge-Kutta can be chosen. Elastic stresses are rotated on the markers, which are also used to track all relevant material properties and solution history fields. The Newtonian nonlinear iteration, however, is handled at the level of the grid points to avoid spurious averaging between markers and grid. Such an arrangement required us to develop a non-standard discretization of the effective strain-rate second invariant. Important feature of the code is its ability to handle stress-free and open-box boundary conditions, in which empty cells are simply eliminated from the discretization, which also solves the biggest problem of the sticky-air approach - namely large viscosity jumps near the free surface. We currently support an arbitrary combination of linear elastic, nonlinear viscous with multiple creep mechanisms, and plastic rheologies based on either a depth-dependent von Mises or pressure-dependent Drucker-Prager yield criteria.LaMEM is being developed as an inherently parallel code. Structurally all its parts are based on the building blocks provided by PETSc library. These include Jacobian-Free Newton-Krylov nonlinear solvers with convergence globalization techniques (line search), equipped with different linear preconditioners. We have also implemented the coupled velocity-pressure multigrid

  17. Marginal flow and gap flow in strongly staggered cascades of slightly convex profiles; Rand- und Spaltstroemungen in stark gestaffelten Verdichtergittern aus schwach gewoelbten Profilen

    Energy Technology Data Exchange (ETDEWEB)

    Sasongko, H. [Technische Univ. Braunschweig (Germany). Inst. fuer Stroemungsmechanik

    1997-09-01

    Marginal flow and gap flow through a highly staggered cascade consisting of slightly convex profiles were investigated in two steps. Cascades without gap were investigated in the first step and cascades with gap in the second. In the first step, a slightly staggered cascade of identical geometry was used for comparison. In the second step, an external rotor cascade of 9C7/32,5C50 profiles with a division ratio t/l = 1.0 and a staggering angle of {lambda} = 50 was used. At a Reynolds number Re{sub j} = 3.5 x 10{sup 5} and gap widths of s/l = 0.0, 0.01 and 0.3, flows, wakes and pressure distributions were measured and diagrams made. The measurements were evaluated by mass averaging and with the aid of the pulse method. In addition to the averaged results of a standard investigation, the dissertation comprises extensive data on 3D flow near the blade ends and at the side wall as a function of blade angles and gap widths between blades and side wall. This was the first time that marginal flow and gap flow of strongly staggered cascades with slightly convex profiles were investigated in a cascade wind tunnel. The findings are therefore quite new and deviate strongly from the results of earlier investigations on strongly convex profiles. The findings were compared with the results of compressor investigations, and good agreement was found. (orig./AKF) [Deutsch] Die vorliegende Arbeit berichtet ueber die in zwei Schritten durchgefuehrten Untersuchungen der Rand- und Spaltstroemungen eines hoch gestaffelten Verdichtergitters aus schwach gewoelbten Profilen. Im ersten Schritt wurde das Gitter ohne Spalt, im zweiten Schritt mit Spalt untersucht. Vergleichsgitter im ersten Schritt war ein zusaetzlich untersuchtes Gitter schwacher Staffelung mit sonst gleicher Geometrie. Vergleichsgitter im zweiten Schritt war das hoch gestaffelte Gitter aus dem ersten Schritt. Das untersuchte Verdichtergitter ist ein Rotor-Aussenschnitt-Gitter aus 9C7/32,5C50-Profilen mit einem

  18. Experimental process investigation of a latent heat energy storage system with a staggered heat exchanger with different phase change materials for solar thermal energy storage applications

    Science.gov (United States)

    Tsolakoglou, Nikolas P.; Koukou, Maria K.; Vrachopoulos, Michalis Gr.; Tachos, Nikolaos; Lymberis, Kostas; Stathopoulos, Vassilis

    2017-11-01

    This work investigates melting and solidification processes of four different Phase Change Materials (PCM) used as latent heat thermal storage system. The experimental rig was consisted of an insulated tank, filled with the under investigation PCM, a staggered heat exchanger to supply or extract heat from the PCM cavity and a water pump to circulate Heat Transfer Fluid (HTF). Both charging (melting) and discharging (solidification) processes were conducted for two different HTF flow rates. The main scope of this work was to develop a first approach and to investigate the behaviour of PCM under various load conditions (different HTF flow rates). Results show that different HTF flow rates affect melting and solidification time periods; in both processes time was reduced while HTF flow rate was increased but in differentways due to the transition from conduction to convection heat transfer mechanisms.

  19. Experimental process investigation of a latent heat energy storage system with a staggered heat exchanger with different phase change materials for solar thermal energy storage applications

    Directory of Open Access Journals (Sweden)

    Tsolakoglou Nikolas P.

    2017-01-01

    Full Text Available This work investigates melting and solidification processes of four different Phase Change Materials (PCM used as latent heat thermal storage system. The experimental rig was consisted of an insulated tank, filled with the under investigation PCM, a staggered heat exchanger to supply or extract heat from the PCM cavity and a water pump to circulate Heat Transfer Fluid (HTF. Both charging (melting and discharging (solidification processes were conducted for two different HTF flow rates. The main scope of this work was to develop a first approach and to investigate the behaviour of PCM under various load conditions (different HTF flow rates. Results show that different HTF flow rates affect melting and solidification time periods; in both processes time was reduced while HTF flow rate was increased but in differentways due to the transition from conduction to convection heat transfer mechanisms.

  20. Real time stagger of electric network advanced analysis functions of a modern control center; Escalonamento em tempo real das funcoes avancadas de analise de rede eletrica de um moderno centro de controle

    Energy Technology Data Exchange (ETDEWEB)

    Zagari, Eduardo Nicola Ferraz

    1996-02-01

    This work presents two models for implementation of staggers for network analysis functions in real time for a control center. The methodology is described. Tests were performed in a electric power system of Campinas region, Sao Paulo sate - Southeast Brazil. Results are presented.

  1. A Randomized controlled trial on safety and efficacy of single intramuscular versus staggered oral dose of 600 000IU Vitamin D in treatment of nutritional rickets.

    Science.gov (United States)

    Mondal, Krishanu; Seth, Anju; Marwaha, Raman K; Dhanwal, Dinesh; Aneja, Satinder; Singh, Ritu; Sonkar, Pitambar

    2014-06-01

    Comparison of efficacy and safety of two different regimens of vitamin D-600 000 IU as a single intramuscular dose, and 60 000IU orally once a week for 10 weeks-in treatment of nutritional rickets. Children with nutritional rickets (age: 0.5-5 years, n = 61) were randomized to receive either 60 000IU vitamin D orally once a week for 10 weeks or 600 000IU single intramuscular injection. Serum calcium, phosphate, alkaline phosphatase, urinary calcium/creatinine ratio, serum 25 hydroxy vitamin D and radiological score were compared at 12-week follow-up. No difference was found in efficacy of the two regimens on comparing biochemical and radiological parameters. Serum 25 hydroxy vitamin D >100 ng/ml was found in two children in the oral group and one child in the intramuscular group. No child developed hypercalcemia or hypercalciuria after starting treatment. Staggered oral and one-time intramuscular administrations of 600 000IU vitamin D are equally effective and safe in treatment of nutritional rickets. © The Author [2014]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Staggered-electromagnetophoresis with a Split-flow System for the Separation of Microparticles by a Hollow Fiber-embedded PDMS Microchip.

    Science.gov (United States)

    Iiguni, Yoshinori; Tanaka, Ayaka; Kitagawa, Shinya; Ohtani, Hajime

    2016-01-01

    A novel microchip separation system for microparticles based on electromagnetophoresis (EMP) was developed. In this system, focusing and separation of flowing microparticles in a microchannel could be performed by staggered-EMP by controlling the electric current applied to the channel locally combined with the split-flow system for fractionation of eluates. To apply the electric current through the flushing medium in the microchannel, a hollow fiber-embedded microchip with multiple electrodes was fabricated. The hollow fiber was made by a semi-permeable membrane and could separate small molecules. This microchip allowed us to apply the electric current to a part of the microchannel without any pressure control device because a main channel contacted with the subchannels that had electrodes through the semi-permeable membrane. Moreover, the separation using this microchip was combined with the split-flow system at two outlets to improve separation efficiency. Using this system, with the split-flow ratio of 10:1, 87% of 3 μm polystyrene (PS) latex particles were isolated from a mixture of 3 and 10 μm particles. Even the separation of 6 and 10 μm PS particles was achieved with about 77% recovery and 100% purity. In addition, by controlling the applied current, size fractionation of polypropylene (PP) particles was demonstrated. Moreover, biological particles such as pollens could be separated with high separation efficiency by this technique.

  3. A Newton-Krylov method with approximate Jacobian for implicit solution of Navier-Stokes on staggered overset-curvilinear grids with immersed boundaries

    Science.gov (United States)

    Asgharzadeh, Hafez; Borazjani, Iman

    2014-11-01

    Time step-size restrictions and low convergence rates are major bottle necks for implicit solution of the Navier-Stokes in simulations involving complex geometries with moving boundaries. Newton-Krylov method (NKM) is a combination of a Newton-type method for super-linearly convergent solution of nonlinear equations and Krylov subspace methods for solving the Newton correction equations, which can theoretically address both bottle necks. The efficiency of this method vastly depends on the Jacobian forming scheme e.g. automatic differentiation is very expensive and Jacobian-free methods slow down as the mesh is refined. A novel, computationally efficient analytical Jacobian for NKM was developed to solve unsteady incompressible Navier-Stokes momentum equations on staggered curvilinear grids with immersed boundaries. The NKM was validated and verified against Taylor-Green vortex and pulsatile flow in a 90 degree bend and efficiently handles complex geometries such as an intracranial aneurysm with multiple overset grids, pulsatile inlet flow and immersed boundaries. The NKM method is shown to be more efficient than the semi-implicit Runge-Kutta methods and Jabobian-free Newton-Krylov methods. We believe NKM can be applied to many CFD techniques to decrease the computational cost. This work was supported partly by the NIH Grant R03EB014860, and the computational resources were partly provided by Center for Computational Research (CCR) at University at Buffalo.

  4. Classification for the universal scaling of Néel temperature and staggered magnetization density of three-dimensional dimerized spin-1/2 antiferromagnets

    Science.gov (United States)

    Tan, D.-R.; Li, C.-D.; Jiang, F.-J.

    2018-03-01

    Inspired by the recent theoretical development relevant to the experimental data of TlCuCl3, particularly those associated with the universal scaling between the Néel temperature TN and the staggered magnetization density Ms, we carry out a detailed investigation of three-dimensional (3D) dimerized quantum antiferromagnets using the first-principles quantum Monte Carlo calculations. Through this study we wish to better understand the microscopic effects on these scaling relations of TN and Ms, hence to shed light on some of the observed inconsistency between the theoretical and the experimental results. Remarkably, for the considered 3D dimerized models, we find that the established universal scaling relations are not only valid, but can each be categorized within its kind by the amount of stronger antiferromagnetic couplings connected to each spin. Convincing numerical evidence is provided to support the validity of this classification scheme. Based on all the related results known in the literature, we further argue that the proposed categorization for the universal scaling investigated in our paper should be applicable for 3D dimerized spin systems with (certain kinds of) quenched disorder and (or) on lattice geometries other than those considered here. The relevance of the outcomes presented in this investigation to the experiments of TlCuCl3 is briefly discussed as well.

  5. Solving phase appearance/disappearance two-phase flow problems with high resolution staggered grid and fully implicit schemes by the Jacobian-free Newton–Krylov Method

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Ling; Zhao, Haihua; Zhang, Hongbin

    2016-04-01

    The phase appearance/disappearance issue presents serious numerical challenges in two-phase flow simulations. Many existing reactor safety analysis codes use different kinds of treatments for the phase appearance/disappearance problem. However, to our best knowledge, there are no fully satisfactory solutions. Additionally, the majority of the existing reactor system analysis codes were developed using low-order numerical schemes in both space and time. In many situations, it is desirable to use high-resolution spatial discretization and fully implicit time integration schemes to reduce numerical errors. In this work, we adapted a high-resolution spatial discretization scheme on staggered grid mesh and fully implicit time integration methods (such as BDF1 and BDF2) to solve the two-phase flow problems. The discretized nonlinear system was solved by the Jacobian-free Newton Krylov (JFNK) method, which does not require the derivation and implementation of analytical Jacobian matrix. These methods were tested with a few two-phase flow problems with phase appearance/disappearance phenomena considered, such as a linear advection problem, an oscillating manometer problem, and a sedimentation problem. The JFNK method demonstrated extremely robust and stable behaviors in solving the two-phase flow problems with phase appearance/disappearance. No special treatments such as water level tracking or void fraction limiting were used. High-resolution spatial discretization and second- order fully implicit method also demonstrated their capabilities in significantly reducing numerical errors.

  6. The StaggerGrid project

    DEFF Research Database (Denmark)

    Collet, Remo; Magic, Zazralt; Asplund, Martin

    2011-01-01

    In this contribution, we present the STAGGERGRID, a collaborative project for the construction of a comprehensive grid of time-dependent, three-dimensional (3-D), hydrodynamic model atmospheres of solar- and late-type stars with different effective temperatures, surface gravities, and chemical...

  7. The STAGGER-grid: A grid of 3D stellar atmosphere models. V. Synthetic stellar spectra and broad-band photometry

    Science.gov (United States)

    Chiavassa, A.; Casagrande, L.; Collet, R.; Magic, Z.; Bigot, L.; Thévenin, F.; Asplund, M.

    2018-03-01

    Context. The surface structures and dynamics of cool stars are characterised by the presence of convective motions and turbulent flows which shape the emergent spectrum. Aims: We used realistic three-dimensional (3D) radiative hydrodynamical simulations from the STAGGER-grid to calculate synthetic spectra with the radiative transfer code OPTIM3D for stars with different stellar parameters to predict photometric colours and convective velocity shifts. Methods: We calculated spectra from 1000 to 200 000 Å with a constant resolving power of λ/Δλ = 20 000 and from 8470 and 8710 Å (Gaia Radial Velocity Spectrometer - RVS - spectral range) with a constant resolving power of λ/Δλ = 300 000. Results: We used synthetic spectra to compute theoretical colours in the Johnson-Cousins UBV (RI)C, SDSS, 2MASS, Gaia, SkyMapper, Strömgren systems, and HST-WFC3. Our synthetic magnitudes are compared with those obtained using 1D hydrostatic models. We showed that 1D versus 3D differences are limited to a small percent except for the narrow filters that span the optical and UV region of the spectrum. In addition, we derived the effect of the convective velocity fields on selected Fe I lines. We found the overall convective shift for 3D simulations with respect to the reference 1D hydrostatic models, revealing line shifts of between -0.235 and +0.361 km s-1. We showed a net correlation of the convective shifts with the effective temperature: lower effective temperatures denote redshifts and higher effective temperatures denote blueshifts. We conclude that the extraction of accurate radial velocities from RVS spectra need an appropriate wavelength correction from convection shifts. Conclusions: The use of realistic 3D hydrodynamical stellar atmosphere simulations has a small but significant impact on the predicted photometry compared with classical 1D hydrostatic models for late-type stars. We make all the spectra publicly available for the community through the POLLUX database

  8. Toward Eco-Friendly and Highly Efficient Solar Water Splitting Using In2S3/Anatase/Rutile TiO2Dual-Staggered-Heterojunction Nanodendrite Array Photoanode.

    Science.gov (United States)

    Yang, Jih-Sheng; Wu, Jih-Jen

    2018-01-31

    The TiO 2 -based heterojunction nanodendrite (ND) array composed of anatase nanoparticles (ANPs) on the surface of the rutile ND (RND) array is selected as the model photoanode to demonstrate the strategies toward eco-friendly and efficient solar water splitting using neutral electrolyte and seawater. Compared with the performances in alkaline electrolyte, a non-negligible potential drop across the electrolyte as well as impeded charge injection and charge separation is monitored in the ANP/RND array photoanode with neutral electrolyte, which are, respectively, ascribed to the series resistance of neutral electrolyte, the fundamentally pH-dependent water oxidation mechanism on TiO 2 surface, as well as the less band bending at the interface of TiO 2 and neutral electrolyte. Accordingly, a TiO 2 -based dual-staggered heterojunction ND array photoanode is further designed in this work to overcome the issue of less band bending with the neutral electrolyte. The improvement of charge separation efficiency is realized by the deposition of a transparent In 2 S 3 layer on the ANP/RND array photoanode for constructing additional staggered heterojunction. Under illumination of AM 1.5G (100 mW cm -2 ), the improved photocurrent densities acquired both in neutral electrolyte and seawater at 1.23 V vs reversible hydrogen electrode (RHE), which approach the theoretical value for rutile TiO 2 , are demonstrated in the dual-staggered-heterojunction ND array photoanode. Faradaic efficiencies of ∼95 and ∼32% for solar water oxidation in neutral electrolyte and solar seawater oxidation for 2 h are acquired at 1.23 V vs RHE, respectively.

  9. A Newton–Krylov method with an approximate analytical Jacobian for implicit solution of Navier–Stokes equations on staggered overset-curvilinear grids with immersed boundaries

    Science.gov (United States)

    Asgharzadeh, Hafez; Borazjani, Iman

    2016-01-01

    The explicit and semi-implicit schemes in flow simulations involving complex geometries and moving boundaries suffer from time-step size restriction and low convergence rates. Implicit schemes can be used to overcome these restrictions, but implementing them to solve the Navier-Stokes equations is not straightforward due to their non-linearity. Among the implicit schemes for nonlinear equations, Newton-based techniques are preferred over fixed-point techniques because of their high convergence rate but each Newton iteration is more expensive than a fixed-point iteration. Krylov subspace methods are one of the most advanced iterative methods that can be combined with Newton methods, i.e., Newton-Krylov Methods (NKMs) to solve non-linear systems of equations. The success of NKMs vastly depends on the scheme for forming the Jacobian, e.g., automatic differentiation is very expensive, and matrix-free methods without a preconditioner slow down as the mesh is refined. A novel, computationally inexpensive analytical Jacobian for NKM is developed to solve unsteady incompressible Navier-Stokes momentum equations on staggered overset-curvilinear grids with immersed boundaries. Moreover, the analytical Jacobian is used to form preconditioner for matrix-free method in order to improve its performance. The NKM with the analytical Jacobian was validated and verified against Taylor-Green vortex, inline oscillations of a cylinder in a fluid initially at rest, and pulsatile flow in a 90 degree bend. The capability of the method in handling complex geometries with multiple overset grids and immersed boundaries is shown by simulating an intracranial aneurysm. It was shown that the NKM with an analytical Jacobian is 1.17 to 14.77 times faster than the fixed-point Runge-Kutta method, and 1.74 to 152.3 times (excluding an intensively stretched grid) faster than automatic differentiation depending on the grid (size) and the flow problem. In addition, it was shown that using only the

  10. A Newton-Krylov method with an approximate analytical Jacobian for implicit solution of Navier-Stokes equations on staggered overset-curvilinear grids with immersed boundaries.

    Science.gov (United States)

    Asgharzadeh, Hafez; Borazjani, Iman

    2017-02-15

    The explicit and semi-implicit schemes in flow simulations involving complex geometries and moving boundaries suffer from time-step size restriction and low convergence rates. Implicit schemes can be used to overcome these restrictions, but implementing them to solve the Navier-Stokes equations is not straightforward due to their non-linearity. Among the implicit schemes for nonlinear equations, Newton-based techniques are preferred over fixed-point techniques because of their high convergence rate but each Newton iteration is more expensive than a fixed-point iteration. Krylov subspace methods are one of the most advanced iterative methods that can be combined with Newton methods, i.e., Newton-Krylov Methods (NKMs) to solve non-linear systems of equations. The success of NKMs vastly depends on the scheme for forming the Jacobian, e.g., automatic differentiation is very expensive, and matrix-free methods without a preconditioner slow down as the mesh is refined. A novel, computationally inexpensive analytical Jacobian for NKM is developed to solve unsteady incompressible Navier-Stokes momentum equations on staggered overset-curvilinear grids with immersed boundaries. Moreover, the analytical Jacobian is used to form preconditioner for matrix-free method in order to improve its performance. The NKM with the analytical Jacobian was validated and verified against Taylor-Green vortex, inline oscillations of a cylinder in a fluid initially at rest, and pulsatile flow in a 90 degree bend. The capability of the method in handling complex geometries with multiple overset grids and immersed boundaries is shown by simulating an intracranial aneurysm. It was shown that the NKM with an analytical Jacobian is 1.17 to 14.77 times faster than the fixed-point Runge-Kutta method, and 1.74 to 152.3 times (excluding an intensively stretched grid) faster than automatic differentiation depending on the grid (size) and the flow problem. In addition, it was shown that using only the

  11. Biosensor enhancement using grooved micromixers: Part II, experimental studies

    Czech Academy of Sciences Publication Activity Database

    Lynn, Nicholas Scott; Bocková, Markéta; Adam, Pavel; Homola, Jiří

    2015-01-01

    Roč. 87, č. 11 (2015), s. 5524-5530 ISSN 0003-2700 R&D Projects: GA ČR(CZ) GBP205/12/G118 Institutional support: RVO:67985882 Keywords : Escherichia coli bacteria * Surface plasmon resonance * Microfluidics Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 5.886, year: 2015

  12. Studi Numerik Karakteristik Pengeringan Batubara pada Fluidized Bed Coal Dyer Terhadap Pengaruh Variasi Temperatur Air Heater dengan Tube Heater Tersusun Staggered dan Perbandingan Volume Chamber dan Volume Batubara Sebesar 50%

    Directory of Open Access Journals (Sweden)

    Ayu Sarah Novrizqa

    2013-03-01

    Full Text Available Indonesia mempunyai sumber daya batubara yang cukup besar dan sebagian besar sumber daya tersebut termasuk ke dalam batubara peringkat rendah berupa lignit dan sub-bituminus yang memiliki kadar air yang tinggi. Tingginya kadar air menyebabkan rendahnya nilai kalor, sehingga pemanfaatan batubara jenis ini menjadi terbatas dan sulit untuk dipasarkan. Oleh karena itu perlu adanya teknologi pengeringan yang dapat meningkatkan nilai kalor dari batubara tersebut. Dalam proses pengeringan akan melibatkan perpindahan panas dan massa. Proses ini akan didefinisikan dalam suatu studi numerik, dimana penelitian ini dilakukan dengan metode numerik dengan software Fluent 6.3.26. Pemilihan kondisi simulasi digunakan model turbulensi k-ε realizable dan skema interpolasi first-order upwind. Serta mempelajari pengaruh temperatur inlet udara pengering yang divariasikan. Variasi temperatur adalah 316 K, 327 K, 339 K. Dari penelitian ini  dapat diketahui nilai drying rate serta pengaruh temperatur dan posisi batubara dalam proses pengeringan pada drying chamber fluidized bed coal dryer dengan tube heater tersusun staggered serta pengaruh dari perbandingan volume batubara dengan volume chamber sebesar 50%. Moisture content batubara yang paling banyak berkurang dialami oleh temperature outlet terbesar yaitu 339 K dari 0,22 hingga 0,0167. Laju pengeringan yang memiliki waktu paling cepat yaitu pada temperatur 339 K, sekitar 1100 detik, sedangkan yang memiliki waktu paling lama yaitu pada temperatur 316 K, sekitar 4600 detik.

  13. An improved pseudotargeted metabolomics approach using multiple ion monitoring with time-staggered ion lists based on ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry

    International Nuclear Information System (INIS)

    Wang, Yang; Liu, Fang; Li, Peng; He, Chengwei; Wang, Ruibing; Su, Huanxing; Wan, Jian-Bo

    2016-01-01

    Pseudotargeted metabolomics is a novel strategy integrating the advantages of both untargeted and targeted methods. The conventional pseudotargeted metabolomics required two MS instruments, i.e., ultra-high performance liquid chromatography/quadrupole-time- of-flight mass spectrometry (UHPLC/Q-TOF MS) and UHPLC/triple quadrupole mass spectrometry (UHPLC/QQQ-MS), which makes method transformation inevitable. Furthermore, the picking of ion pairs from thousands of candidates and the swapping of the data between two instruments are the most labor-intensive steps, which greatly limit its application in metabolomic analysis. In the present study, we proposed an improved pseudotargeted metabolomics method that could be achieved on an UHPLC/Q-TOF/MS instrument operated in the multiple ion monitoring (MIM) mode with time-staggered ion lists (tsMIM). Full scan-based untargeted analysis was applied to extract the target ions. After peak alignment and ion fusion, a stepwise ion picking procedure was used to generate the ion lists for subsequent single MIM and tsMIM. The UHPLC/Q-TOF tsMIM MS-based pseudotargeted approach exhibited better repeatability and a wider linear range than the UHPLC/Q-TOF MS-based untargeted metabolomics method. Compared to the single MIM mode, the tsMIM significantly increased the coverage of the metabolites detected. The newly developed method was successfully applied to discover plasma biomarkers for alcohol-induced liver injury in mice, which indicated its practicability and great potential in future metabolomics studies. - Highlights: • An UHPLC/Q-TOF tsMIM MS-based pseudotargeted metabolomics was proposed. • Compared to full scan, the improved method exhibits better repeatability and a wider linear range. • The proposed method could achieve pseudotargeted analysis on one UHPLC/Q-TOF/MS instrument. • The developed method was successfully used to discover biomarkers for alcohol-induced liver injury.

  14. An improved pseudotargeted metabolomics approach using multiple ion monitoring with time-staggered ion lists based on ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Wang, Yang; Liu, Fang; Li, Peng; He, Chengwei; Wang, Ruibing; Su, Huanxing; Wan, Jian-Bo

    2016-07-13

    Pseudotargeted metabolomics is a novel strategy integrating the advantages of both untargeted and targeted methods. The conventional pseudotargeted metabolomics required two MS instruments, i.e., ultra-high performance liquid chromatography/quadrupole-time- of-flight mass spectrometry (UHPLC/Q-TOF MS) and UHPLC/triple quadrupole mass spectrometry (UHPLC/QQQ-MS), which makes method transformation inevitable. Furthermore, the picking of ion pairs from thousands of candidates and the swapping of the data between two instruments are the most labor-intensive steps, which greatly limit its application in metabolomic analysis. In the present study, we proposed an improved pseudotargeted metabolomics method that could be achieved on an UHPLC/Q-TOF/MS instrument operated in the multiple ion monitoring (MIM) mode with time-staggered ion lists (tsMIM). Full scan-based untargeted analysis was applied to extract the target ions. After peak alignment and ion fusion, a stepwise ion picking procedure was used to generate the ion lists for subsequent single MIM and tsMIM. The UHPLC/Q-TOF tsMIM MS-based pseudotargeted approach exhibited better repeatability and a wider linear range than the UHPLC/Q-TOF MS-based untargeted metabolomics method. Compared to the single MIM mode, the tsMIM significantly increased the coverage of the metabolites detected. The newly developed method was successfully applied to discover plasma biomarkers for alcohol-induced liver injury in mice, which indicated its practicability and great potential in future metabolomics studies. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. An improved pseudotargeted metabolomics approach using multiple ion monitoring with time-staggered ion lists based on ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yang; Liu, Fang; Li, Peng; He, Chengwei; Wang, Ruibing; Su, Huanxing; Wan, Jian-Bo, E-mail: jbwan@umac.mo

    2016-07-13

    Pseudotargeted metabolomics is a novel strategy integrating the advantages of both untargeted and targeted methods. The conventional pseudotargeted metabolomics required two MS instruments, i.e., ultra-high performance liquid chromatography/quadrupole-time- of-flight mass spectrometry (UHPLC/Q-TOF MS) and UHPLC/triple quadrupole mass spectrometry (UHPLC/QQQ-MS), which makes method transformation inevitable. Furthermore, the picking of ion pairs from thousands of candidates and the swapping of the data between two instruments are the most labor-intensive steps, which greatly limit its application in metabolomic analysis. In the present study, we proposed an improved pseudotargeted metabolomics method that could be achieved on an UHPLC/Q-TOF/MS instrument operated in the multiple ion monitoring (MIM) mode with time-staggered ion lists (tsMIM). Full scan-based untargeted analysis was applied to extract the target ions. After peak alignment and ion fusion, a stepwise ion picking procedure was used to generate the ion lists for subsequent single MIM and tsMIM. The UHPLC/Q-TOF tsMIM MS-based pseudotargeted approach exhibited better repeatability and a wider linear range than the UHPLC/Q-TOF MS-based untargeted metabolomics method. Compared to the single MIM mode, the tsMIM significantly increased the coverage of the metabolites detected. The newly developed method was successfully applied to discover plasma biomarkers for alcohol-induced liver injury in mice, which indicated its practicability and great potential in future metabolomics studies. - Highlights: • An UHPLC/Q-TOF tsMIM MS-based pseudotargeted metabolomics was proposed. • Compared to full scan, the improved method exhibits better repeatability and a wider linear range. • The proposed method could achieve pseudotargeted analysis on one UHPLC/Q-TOF/MS instrument. • The developed method was successfully used to discover biomarkers for alcohol-induced liver injury.

  16. Developing and verifying design and operational criteria for the active sludge process involving staggered feed with the elimination of nitrogen; Desarrollo y verificacion de criterios de diseno y oporacion para el proceso de fangos activos de alimentacion escalonada con eliminacion de nitrogeno

    Energy Technology Data Exchange (ETDEWEB)

    Larrea, L.; Larrea, A.; Ayesa, E.; Rodrigo, J. C.

    2000-07-01

    This study focused on the staggered feed process with three denitrification-nitrification reactor phases. In the first place, criteria for the optimum selection of design parameters were developed using simulations based on mathematical models of the process and efficient operational strategies were suggested. The results of the simulation were then verified by means of tests in a pilot plant. In regard to the design parameters, the simulation studies showed that the optimum in-flow to the three anoxic reactors lies within the range 40-40-20% to 33-33-34%, depending on the characteristics of the waste water and the requirements of the effluent. These latter two conditions and, therefore, the distribution of the inflow, determine the volumes of the aerobic and anoxic reactors. The operating strategy proposed consists in reducing the concentration of dissolved oxygen in the first two aerobic reactors and using optional areas in the last D-N stage of the process. The experimental results obtained confirmed the validity of the design and operational criteria that had been developed. Finally, it was found that if IWA model no. 1 is appropriately calibrated, it has a great capacity for predicting the behaviour of the staggered feed process. (Author) 12 refs.

  17. PERFORMANCE CHARACTERISTICS OF HERRINGBONE-GROOVED JOURNAL BEARINGS OPERATING AT HIGH ECCENTRICITY RATIOS AND WITH MISALIGNMENT.

    Science.gov (United States)

    journal bearing with compressible lubricant is solved by the numerical method of matrix influence coefficients for the case of arbitrary eccentricity and misalignment. Performance characteristics are presented for one particular bearing over the range 0 < Lambda < 20. Results are presented showing the restoring moment due to misalignment, the effect of L/D ratio at large eccentricity and the influence of eccentricity ratio on the optimum values of groove parameters for maximum radial stiffness. Comparison is made with experimental results.

  18. Modified herringbone reconstruction on Au(1 1 1) induced by self-assembled Azure A islands

    Science.gov (United States)

    Rossel, Frédéric; Brodard, Pierre; Patthey, François; Richardson, Neville V.; Schneider, Wolf-Dieter

    2008-07-01

    Upon submonolayer deposition of Azure A molecules onto reconstructed Au(1 1 1), two-dimensional quasi-rectangular islands are observed by low-temperature scanning tunneling microscopy. Strikingly, the 22 × √3 reconstruction with alternating hexagonal close packed (hcp) and face centered cubic (fcc) domains of the native Au(1 1 1) surface layer is found to be strongly modified underneath the self-assembled islands of Azure A molecules. The bridge-hcp-bridge-fcc-bridge period of 63 Å on clean Au(1 1 1) is expanded by about 12% and occasionally reaches even 22%. This increase of the unreconstructed fcc areas underneath the molecular islands reflects a partial lifting of the reconstruction caused by the interaction between the adsorbed molecules and the outermost Au atoms at the molecule-metal interface.

  19. Design curves for optimizing stability of herringbone-grooved journal bearings

    Science.gov (United States)

    Fleming, D. P.; Hamrock, B. J.

    1973-01-01

    Curves span wide range of operating conditions, including: lubricant compressibility numbers from 0 to 80, bearing length-to-diameter ratios from 1/4 to 2, and either rotating or stationary grooved members.

  20. Rationale, design and methods for a staggered-entry, waitlist controlled clinical trial of the impact of a community-based, family-centred, multidisciplinary program focussed on activity, food and attitude habits (Curtin University’s Activity, Food and Attitudes Program—CAFAP among overweight adolescents

    Directory of Open Access Journals (Sweden)

    Straker Leon M

    2012-06-01

    Full Text Available Abstract Background Current estimates place just under one quarter of adolescents in Australia as overweight or obese. Adolescence has been identified as a critical period for the development of obesity, yet despite this recognition, there is limited systematic research into or evaluation of interventions for overweight adolescents. Reviews have concluded that there is a substantive evidence gap for effective intervention, but physical activity, lifestyle change and family involvement have been identified as promising foci for treatment. Methods This paper reports on the development of a staggered-entry, waitlist controlled clinical trial to assess the impact of a multidisciplinary intervention aiming to change the poor health trajectory of overweight adolescents and help them avoid morbid obesity in adulthood—Curtin University’s Activity, Food and Attitudes Program (CAFAP. 96 adolescents, aged 11–16 years, and parents, will attend twice weekly during an 8 week intensive multidisciplinary program with maintenance follow-up focussed on improving activity, food and attitude habits. Follow-up assessments will be conducted immediately after completing the intensive program, and at 3, 6 and 12 months post intensive program. Main outcomes will be objectively-measured physical activity, sedentary behaviour and activity behaviours; food intake (measured by 3 day diary and food behaviours; body composition, fitness and physical function; mental and social well-being (quality of life, mood and attitudes, and family functioning. Discussion This trial will provide important information to understand whether a community based multidisciplinary intervention can have short and medium term effects on activity and food habits, attitudes, and physical and mental health status of overweight adolescents. Trial registration Australian New Zealand Clinical Trials Registry ACTRN12611001187932.

  1. Rapid detection of Hendra virus antibodies: an integrated device with nanoparticle assay and chaotic micromixing.

    Science.gov (United States)

    Petkovic, K; Metcalfe, G; Chen, H; Gao, Y; Best, M; Lester, D; Zhu, Y

    2016-12-20

    Current diagnosis of infectious diseases such as Hendra virus (HeV) relies mostly on laboratory-based tests. There is an urgent demand for rapid diagnosis technology to detect and identify these diseases in humans and animals so that disease spread can be controlled. In this study, an integrated lab-on-a-chip device using a magnetic nanoparticle immunoassay is developed. The key features of the device are the chaotic fluid mixing, achieved by magnetically driven motion of nanoparticles with the optimal mixing protocol developed using chaotic transport theory, and the automatic liquid handling system for loading reagents and samples. The device has been demonstrated to detect Hendra virus antibodies in dilute horse serum samples within a short time of 15 minutes and the limit of detection is about 0.48 ng ml -1 . The device platform can potentially be used for field detection of viruses and other biological and chemical substances.

  2. Chaotic micromixer utilizing electro-osmosis and induced charge electro-osmosis in eccentric annulus

    International Nuclear Information System (INIS)

    Feng, Huicheng; Wong, Teck Neng; Marcos; Che, Zhizhao

    2016-01-01

    Efficient mixing is of significant importance in numerous chemical and biomedical applications but difficult to realize rapidly in microgeometries due to the lack of turbulence. We propose to enhance mixing by introducing Lagrangian chaos through electro-osmosis (EO) or induced charge electro-osmosis (ICEO) in an eccentric annulus. The analysis reveals that the created Lagrangian chaos can achieve a homogeneous mixing much more rapidly than either the pure EO or the pure ICEO. Our systematic investigations on the key parameters, ranging from the eccentricity, the alternating time period, the number of flow patterns in one time period, to the specific flow patterns utilized for the Lagrangian chaos creation, present that the Lagrangian chaos is considerably robust. The system can obtain a good mixing effect with wide ranges of eccentricity, alternating time period, and specific flow patterns utilized for the Lagrangian chaos creation as long as the number of flow patterns in one time period is two. As the electric field increases, the time consumption for homogenous mixing is reduced more remarkably for the Lagrangian chaos of the ICEO than that of the EO.

  3. Geometric effects on mixing performance in a novel passive micromixer with trapezoidal-zigzag channels

    DEFF Research Database (Denmark)

    The, Hai Le; Ta, Bao Quoc; Lê Thanh, Hoà

    2015-01-01

    advection. The effects of geometric parameters of the TZM on mixing performance are systematically investigated by the Taguchi method and numerical simulations in COMSOL Multiphysics. The number of mixing units, the slope angle of the trapezoidal channel, the height of the constriction element...

  4. Odd - even staggering, a result of γ - band split

    International Nuclear Information System (INIS)

    Singh, M.; Gupta, D.K.; Singh, Yuvraj; Gupta, K.K.; Bihari, Chhail; Sharma, Aparna; Varshney, A.K.; Varshney, Mani

    2011-01-01

    The structure of low - lying K = 2+ gamma band in even - even nuclei represents quadrupole vibration breaking axial symmetry in unified collective model of Bohr-Mottelson. In the group theoretical approach of the Interacting boson model (IBM) the band structure can belong to one of the three limiting symmetries of U (6) algebra viz. U (5), SU (3) and O (6), corresponding to the anharmonic vibrator, deformed rotor and γ - unstable respectively

  5. An implicit non-staggered Cartesian grid method for incompressible ...

    Indian Academy of Sciences (India)

    In the second category, a number of discrete points are selected on the immersed surface where the boundary conditions ..... equation and variable index. This system can be solved using Newton's ... (and thus the mass flux) that satisfies mass conservation law, but not necessarily a divergence- free velocity field. This can ...

  6. An implicit non-staggered Cartesian grid method for incompressible ...

    Indian Academy of Sciences (India)

    The immersed boundary method can be broadly classified into two groups; the continuous forcing approach and the direct forcing technique. Peskin (1972) first ..... avoided by using a smaller t which makes the whole time integration technique stable. How- ever, in such a situation purpose of using the implicit method is ...

  7. Direct numerical simulations of drag reduction in turbulent channel flow over bio-inspired herringbone riblet-texture

    NARCIS (Netherlands)

    Benschop, H.O.G.; Westerweel, J.; Breugem, W.P.

    2015-01-01

    The use of drag reducing surface textures is a promising passive method to reduce fuel consumption. Probably most wellknown is the utilisation of shark-skin inspired ridges or riblets parallel to the mean flow. They can reduce drag up to 10%. Recently another bio-inspired texture based on bird

  8. Experimental and numerical investigations of the dry-low-NOx hydrogen micromix combustion chamber of an industrial gas turbine

    OpenAIRE

    A. Haj Ayed; K. Kusterer; H.H.-W. Funke; J. Keinz; C. Striegan; D. Bohn

    2015-01-01

    Combined with the use of renewable energy sources for its production, hydrogen represents a possible alternative gas turbine fuel within future low emission power generation. Due to the large difference in the physical properties of hydrogen compared to other fuels such as natural gas, well established gas turbine combustion systems cannot be directly applied for dry-low-NOx (DLN) hydrogen combustion. Thus, the development of DLN combustion technologies is an essential and challenging task fo...

  9. CFD based exploration of the dry-low-NOx hydrogen micromix combustion technology at increased energy densities

    OpenAIRE

    A. Haj Ayed; K. Kusterer; H.H.-W. Funke; J. Keinz; D. Bohn

    2017-01-01

    Combined with the use of renewable energy sources for its production, hydrogen represents a possible alternative gas turbine fuel within future low emission power generation. Due to the large difference in the physical properties of hydrogen compared to other fuels such as natural gas, well established gas turbine combustion systems cannot be directly applied for dry-low-NOx (DLN) hydrogen combustion. Thus, the development of DLN combustion technologies is an essential and challenging task fo...

  10. A simple planar micromixer with low-pressure drop for disposable lab-on-a-chip (LOC) systems

    Science.gov (United States)

    Bhagat, Ali Asgar S.; Peterson, Erik T. K.; Papautsky, Ian

    2007-01-01

    In this work the design and fabrication of a novel passive microfluidic mixer capable of achieving mixing in shorter distances and lower Reynolds numbers (Re) is reported. Passive mixers typically rely on the channel geometry to mix fluids, and many previously reported designs work efficiently only at moderate to high Re and are often difficult to fabricate as they incorporate complex 3-D structures within the channel. The mixer design discussed in this work achieves good mixing at low Re, has planar geometry and thus is simpler to fabricate and integrate with existing labon- a-chip (LOC) technologies. The design incorporates triangular notches patterned along the channel walls to laminate the flow, thus enhancing mixing. Numerical and experimental studies to determine the effect of the notch dimensions and placement within the microchannel were carried out to optimize the mixing performance. Results show that the final mixer design is efficient at mixing fluids at low Re. The mixer is fabricated in polydimethylsiloxane (PDMS) bonded to glass slides and tested using fluorescence dyes. Results show that the new design exhibit complete mixing at Re benefit a wide range of LOC applications where space is limited.

  11. A monolithic and flexible fluoropolymer film microreactor for organic synthesis applications.

    Science.gov (United States)

    Kim, Jin-Oh; Kim, Heejin; Ko, Dong-Hyeon; Min, Kyoung-Ik; Im, Do Jin; Park, Soo-Young; Kim, Dong-Pyo

    2014-11-07

    A photocurable and viscous fluoropolymer with chemical stability is a highly desirable material for fabrication of microchemical devices. Lack of a reliable fabrication method, however, limits actual applications for organic reactions. Herein, we report fabrication of a monolithic and flexible fluoropolymer film microreactor and its use as a new microfluidic platform. The fabrication involves facile soft lithography techniques that enable partial curing of thin laminates, which can be readily bonded by conformal contact without any external forces. We demonstrate fabrication of various functional channels (~300 μm thick) such as those embedded with either a herringbone micromixer pattern or a droplet generator. Organic reactions under strongly acidic and basic conditions can be carried out in this film microreactor even at elevated temperature with excellent reproducibility. In particular, the transparent film microreactor with good deformability could be wrapped around a light-emitting lamp for close contact with the light source for efficient photochemical reactions with visible light, which demonstrates easy integration with optical components for functional miniaturized systems.

  12. Microfluidic isolation of platelet-covered circulating tumor cells.

    Science.gov (United States)

    Jiang, Xiaocheng; Wong, Keith H K; Khankhel, Aimal H; Zeinali, Mahnaz; Reategui, Eduardo; Phillips, Matthew J; Luo, Xi; Aceto, Nicola; Fachin, Fabio; Hoang, Anh N; Kim, Wooseok; Jensen, Annie E; Sequist, Lecia V; Maheswaran, Shyamala; Haber, Daniel A; Stott, Shannon L; Toner, Mehmet

    2017-10-11

    The interplay between platelets and tumor cells is known to play important roles in metastasis by enhancing tumor cell survival, tumor-vascular interactions, and escape from immune surveillance. However, platelet-covered circulating tumor cells (CTC) are extremely difficult to isolate due to masking or downregulation of surface epitopes. Here we describe a microfluidic platform that takes advantage of the satellite platelets on the surface of these "stealth" CTCs as a ubiquitous surface marker for isolation. Compared to conventional CTC enrichment techniques which rely on known surface markers expressed by tumor cells, platelet-targeted isolation is generally applicable to CTCs of both epithelial and mesenchymal phenotypes. Our approach first depletes unbound, free platelets by means of hydrodynamic size-based sorting, followed by immunoaffinity-based capture of platelet-covered CTCs using a herringbone micromixing device. This method enabled the reliable isolation of CTCs from 66% of lung and 60% of breast cancer (both epithelial) patient samples, as well as in 83% of melanoma (mesenchymal) samples. Interestingly, we observed special populations of CTCs that were extensively covered by platelets, as well as CTC-leukocyte clusters. Because these cloaked CTCs often escape conventional positive and negative isolation mechanisms, further characterization of these cells may uncover important yet overlooked biological information in blood-borne metastasis and cancer immunology.

  13. Transport Phenomena and Interfacial Kinetics in Planar Microfluidic Membraneless Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Abruna, Hector Daniel [Cornell University

    2013-08-01

    Our work is focused on membraneless laminar flow fuel cells, an unconventional fuel cell technology, intended to create a system that not only avoids most typical fuel cell drawbacks, but also achieves the highest power density yet recorded for a non-H{sub 2} fuel cell. We have employed rigorous electrochemistry to characterize the high-energy- density fuel BH4-, providing important mechanistic insight for anode catalyst choice and avoiding deleterious side reactions. Numerous fuel cell oxidants, used in place of O{sub 2}, are compared in a detailed, uniform manner, and a powerful new oxidant, cerium ammonium nitrate (CAN), is described. The high-voltage BH{sub 4}{sup -}/CAN fuel/oxidant combination is employed in a membraneless, room temperature, laminar-flow fuel cell, with herringbone micromixers which provide chaotic-convective flow which, in turn, enhances both the power output and efficiency of the device. We have also been involved in the design of a scaled-up version of the membraneless laminar flow fuel cell intended to provide a 10W output.

  14. A Capital or Capabilities Education Narrative in a World of Staggering Inequalities?

    Science.gov (United States)

    Walker, Melanie

    2012-01-01

    In a world of tremendous inequalities, this paper explores two contrasting normative models for education policy, and the relationship of each to policy, practices and outcomes that can improve lives by reducing injustice and building societies which value capabilities for all. The first model is that of human capital which currently dominates…

  15. Mode and gain analysis for symmetric and staggered grating-waveguide free-electron laser

    OpenAIRE

    Yuan-Yao Lin; Yen-Chieh Huang

    2007-01-01

    A grating-waveguide free-electron laser is driven by an axial electron beam that propagates between two planar gratings. This investigation addresses the mode analysis, gain calculation, and frequency tuning for such a device with arbitrary longitudinal and transverse displacements between the two gratings. It demonstrates that a grating waveguide free-electron laser is a promising coherent THz emitter when it is adopted as a backward-wave oscillator or a distributed-feedback oscillator.

  16. Mode and gain analysis for symmetric and staggered grating-waveguide free-electron laser

    Directory of Open Access Journals (Sweden)

    Yuan-Yao Lin

    2007-03-01

    Full Text Available A grating-waveguide free-electron laser is driven by an axial electron beam that propagates between two planar gratings. This investigation addresses the mode analysis, gain calculation, and frequency tuning for such a device with arbitrary longitudinal and transverse displacements between the two gratings. It demonstrates that a grating waveguide free-electron laser is a promising coherent THz emitter when it is adopted as a backward-wave oscillator or a distributed-feedback oscillator.

  17. Robust picosecond writing of a layered antiferromagnet by staggered spin-orbit fields

    Czech Academy of Sciences Publication Activity Database

    Roy, P.E.; Otxoa, R.M.; Wunderlich, Joerg

    2016-01-01

    Roč. 94, č. 1 (2016), 1-5, č. článku 014439. ISSN 2469-9950 Institutional support: RVO:68378271 Keywords : spintronics * Mn 2 Au * cumnas Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.836, year: 2016

  18. The Finite-Surface Method for incompressible flow: a step beyond staggered grid

    Science.gov (United States)

    Hokpunna, Arpiruk; Misaka, Takashi; Obayashi, Shigeru

    2017-11-01

    We present a newly developed higher-order finite surface method for the incompressible Navier-Stokes equations (NSE). This method defines the velocities as a surface-averaged value on the surfaces of the pressure cells. Consequently, the mass conservation on the pressure cells becomes an exact equation. The only things left to approximate is the momentum equation and the pressure at the new time step. At certain conditions, the exact mass conservation enables the explicit n-th order accurate NSE solver to be used with the pressure treatment that is two or four order less accurate without loosing the apparent convergence rate. This feature was not possible with finite volume of finite difference methods. We use Fourier analysis with a model spectrum to determine the condition and found that the range covers standard boundary layer flows. The formal convergence and the performance of the proposed scheme is compared with a sixth-order finite volume method. Finally, the accuracy and performance of the method is evaluated in turbulent channel flows. This work is partially funded by a research colloaboration from IFS, Tohoku university and ASEAN+3 funding scheme from CMUIC, Chiang Mai University.

  19. Localizing gene regulation reveals a staggered wood decay mechanism for the brown rot fungus Postia placenta

    Science.gov (United States)

    Jiwei Zhang; Gerald N. Presley; Kenneth E. Hammel; Jae-San Ryu; Jon R. Menke; Melania Figueroa; Dehong Hu; Galya Orr; Jonathan S. Schilling

    2016-01-01

    Wood-degrading brown rot fungi are essential recyclers of plant biomass in forest ecosystems. Their efficient cellulolytic systems, which have potential biotechnological applications, apparently depend on a combination of two mechanisms: lignocellulose oxidation (LOX) by reactive oxygen species (ROS) and polysaccharide hydrolysis by a limited set of glycoside...

  20. An experimental study on the onset of detonation downstream of a perforated plate with staggered orifices

    Science.gov (United States)

    Lin, Wei; Zhou, Jin; Lin, Zhiyong; Liu, Shijie

    2017-09-01

    The present study investigated the onset of detonation (OD) process which takes place downstream of a 0.9-mm-thick perforated plate. The orifice diameter of the plate is 1.6 mm with a blockage of 59%, and it was placed perpendicular to the axial direction of a smooth detonation tube. `Stable' mixture C2H2 + 2.5O2 + 70%Ar and `unstable' mixture C2H2 + 5N2O were tested, respectively. Ionization probes and smoked foils were used to record detonation velocities and corresponding cellular patterns. Excellent agreement of the velocity trends and smoked foil results shows that a critical pressure range exists to identify `go' and `no go' of OD downstream of the perforated plate. However, the OD mechanisms for these two gaseous mixtures are distinct: for the `stable' mixture, OD occurs in the downstream near field (6 tube diameters in this study), whereas, OD in the `unstable' mixture could also observed in the far field via the transition of deflagration to detonation after a long duration of quasi-steady regime. This distance reaches up to tens of tube diameters when close to the critical pressure.

  1. Surface Quality of Staggered PCD End Mill in Milling of Carbon Fiber Reinforced Plastics

    Directory of Open Access Journals (Sweden)

    Guangjun Liu

    2017-02-01

    Full Text Available Machined surface quality determines the reliability, wear resistance and service life of carbon fiber reinforced plastic (CFRP workpieces. In this work, the formation mechanism of the surface topography and the machining defects of CFRPs are proposed, and the influence of milling parameters and fiber cutting angles on the surface quality of CFRPs is obtained, which can provide a reference for extended tool life and good surface quality. Trimming and slot milling tests of unidirectional CFRP laminates are performed. The surface roughness of the machined surface is measured, and the influence of milling parameters on the surface roughness is analyzed. A regression model for the surface roughness of CFRP milling is established. A significance test of the regression model is conducted. The machined surface topography of milling CFRP unidirectional laminates with different fiber orientations is analyzed, and the effect of fiber cutting angle on the surface topography of the machined surface is presented by using a digital super depth-of-field microscope and scanning electron microscope (SEM. To study the influence of fiber cutting angle on machining defects, the machined topography under different fiber orientations is analyzed. The slot milling defects and their formation mechanism under different fiber cutting angles are investigated.

  2. Single-shot characterization of enzymatic reaction constants Km and kcat by an acoustic-driven, bubble-based fast micromixer.

    Science.gov (United States)

    Xie, Yuliang; Ahmed, Daniel; Lapsley, Michael Ian; Lin, Sz-Chin Steven; Nawaz, Ahmad Ahsan; Wang, Lin; Huang, Tony Jun

    2012-09-04

    In this work we present an acoustofluidic approach for rapid, single-shot characterization of enzymatic reaction constants K(m) and k(cat). The acoustofluidic design involves a bubble anchored in a horseshoe structure which can be stimulated by a piezoelectric transducer to generate vortices in the fluid. The enzyme and substrate can thus be mixed rapidly, within 100 ms, by the vortices to yield the product. Enzymatic reaction constants K(m) and k(cat) can then be obtained from the reaction rate curves for different concentrations of substrate while holding the enzyme concentration constant. We studied the enzymatic reaction for β-galactosidase and its substrate (resorufin-β-D-galactopyranoside) and found K(m) and k(cat) to be 333 ± 130 μM and 64 ± 8 s(-1), respectively, which are in agreement with published data. Our approach is valuable for studying the kinetics of high-speed enzymatic reactions and other chemical reactions.

  3. Single-shot characterization of enzymatic reaction constants Km and kcat by an acoustic-driven, bubble-based fast micromixer

    Science.gov (United States)

    Xie, Yuliang; Ahmed, Daniel; Lapsley, Michael Ian; Lin, Sz-Chin Steven; Nawaz, Ahmad Ahsan; Wang, Lin; Huang, Tony Jun

    2014-01-01

    In this work we present an acoustofluidic approach for rapid, single-shot characterization of enzymatic reaction constants Km and kcat. The acoustofluidic design involves a bubble anchored in a horseshoe structure which can be stimulated by a piezoelectric transducer to generate vortices in the fluid. The enzyme and substrate can thus be mixed rapidly, within 100 ms, by the vortices to yield the product. Enzymatic reaction constants Km and kcat can then be obtained from the reaction rate curves for different concentrations of substrate while holding the enzyme concentration constant. We studied the enzymatic reaction for β-galactosidase and its substrate (resorufin β-D-galactopyranoside) and found Km and kcat to be 333±130 =M and 64±8 s−1 respectively, which are in agreement with published data. Our approach is valuable for studying the kinetics of high-speed enzymatic reactions and other chemical reactions. PMID:22880882

  4. Controlled peroxide-induced degradation of polypropylene in a twin-screw extruder: change of molecular weight distribution under conditions controlled by micromixing

    NARCIS (Netherlands)

    Iedema, P.D.; Remerie, K.; van der Ham, M.; Biemond, E.; Tacx, J.

    2011-01-01

    Controlled degradation of polypropylene (PP) by peroxide was carried out in a laboratory twin-screw extruder ZSK 18 and the change in Molecular Weight Distribution (MWD) was measured using Size Exclusion Chromatography-Differential Viscosimetry (SEC-DV). The MWD results were compared to MWD

  5. Variable volume combustor with nested fuel manifold system

    Science.gov (United States)

    McConnaughhay, Johnie Franklin; Keener, Christopher Paul; Johnson, Thomas Edward; Ostebee, Heath Michael

    2016-09-13

    The present application provides a combustor for use with a gas turbine engine. The combustor may include a number of micro-mixer fuel nozzles, a fuel manifold system in communication with the micro-mixer fuel nozzles to deliver a flow of fuel thereto, and a linear actuator to maneuver the micro-mixer fuel nozzles and the fuel manifold system.

  6. Determination of turbine runner dynamic behaviour under operating condition by a two-way staggered fluid-structureinteraction method

    International Nuclear Information System (INIS)

    Dompierre, F; Sabourin, M

    2010-01-01

    This paper presents the application of the two-way fluid-structure interaction method introduced by ANSYS to calculate the dynamic behaviour of a Francis turbine runner under operating condition. This time-dependant calculation directly takes into account characteristics of the flow and particularly the pressure fluctuations caused by the rotor-stator interaction. This formulation allows the calculation of the damping forces of the whole system implicitly. Thereafter, the calculated dynamic stress can be used for a fatigue analysis. A verification of the mechanical and fluid simulations used as input for the fluid-structure interaction calculation is first performed. Subsequently, a connection of these two independent simulations is made. A validation according to the hydraulic conditions is made with the measurements from the scale model testing. Afterwards, the static displacement of the runner under the hydraulic load is compared with the results of a classical static analysis for verification purposes. Finally, the natural frequencies deduced by the post-processing of the dynamic portion of the runner displacement with respect to time are compared with the natural frequencies obtained from a classical acoustic modal analysis. All comparisons show a good agreement with experimental data or results obtained with conventional methods.

  7. Semileptonic B to D Decays at Nonzero Recoil with 2+1 Flavors of Improved Staggered Quarks

    International Nuclear Information System (INIS)

    Qiu, Si-Wei; DeTar, Carleton; Du, Daping; Kronfeld, Andreas S.; Laiho, Jack; Van de Water, Ruth S.

    2011-01-01

    The Fermilab Lattice-MILC collaboration is completing a comprehensive program of heavy-light physics on the MILC (2+1)-flavor asqtad ensembles with lattice spacings as small as 0.045 fm and light-to-strange-quark mass ratios as low as 1/20. We use the Fermilab interpretation of the clover action for heavy valence quarks and the asqtad action for light valence quarks. The central goal of the program is to provide ever more exacting tests of the unitarity of the CKM matrix. We give a progress report on one part of the program, namely the analysis of the semileptonic decay B to D at both zero and nonzero recoil. Although final results are not presented, we discuss improvements in the analysis methods, the statistical errors, and the parameter coverage that we expect will lead to a significant reduction in the final error for |V cb | from this decay channel.

  8. Felix Cornu (1882-1909): Staggering Career of a Mineralogist, the Founder of Colloidal Chemistry in Geology

    Czech Academy of Sciences Publication Activity Database

    Ulrych, Jaromír

    2003-01-01

    Roč. 15, - (2003), s. 199 ISSN 1210-9606. [Hibsch 2002 Symposium. Teplá near Třebenice, Ústí nad Labem, Mariánské Lázně, 03.06.2002-08.06.2002] Institutional research plan: CEZ:AV0Z3013912 Keywords : Cornu, Felix * mineralogist * colloidal chemistry Subject RIV: DB - Geology ; Mineralogy http://geolines.gli.cas.cz/fileadmin/volumes/volume15/G15-199.pdf

  9. Biomechanical analysis of press-extension technique on degenerative lumbar with disc herniation and staggered facet joint

    Directory of Open Access Journals (Sweden)

    Hong-gen Du

    2016-05-01

    Full Text Available This study investigates the effect of a new Chinese massage technique named “press-extension” on degenerative lumbar with disc herniation and facet joint dislocation, and provides a biomechanical explanation of this massage technique. Self-developed biomechanical software was used to establish a normal L1–S1 lumbar 3D FE model, which integrated the spine CT and MRI data-based anatomical structure. Then graphic technique is utilized to build a degenerative lumbar FE model with disc herniation and facet joint dislocation. According to the actual press-extension experiments, mechanic parameters are collected to set boundary condition for FE analysis. The result demonstrated that press-extension techniques bring the annuli fibrosi obvious induction effect, making the central nucleus pulposus forward close, increasing the pressure in front part. Study concludes that finite element modelling for lumbar spine is suitable for the analysis of press-extension technique impact on lumbar intervertebral disc biomechanics, to provide the basis for the disease mechanism of intervertebral disc herniation using press-extension technique.

  10. On Long-Time Instabilities in Staggered Finite Difference Simulations of the Seismic Acoustic Wave Equations on Discontinuous Grids

    KAUST Repository

    Gao, Longfei

    2017-10-26

    We consider the long-time instability issue associated with finite difference simulation of seismic acoustic wave equations on discontinuous grids. This issue is exhibited by a prototype algebraic problem abstracted from practical application settings. Analysis of this algebraic problem leads to better understanding of the cause of the instability and provides guidance for its treatment. Specifically, we use the concept of discrete energy to derive the proper solution transfer operators and design an effective way to damp the unstable solution modes. Our investigation shows that the interpolation operators need to be matched with their companion restriction operators in order to properly couple the coarse and fine grids. Moreover, to provide effective damping, specially designed diffusive terms are introduced to the equations at designated locations and discretized with specially designed schemes. These techniques are applied to simulations in practical settings and are shown to lead to superior results in terms of both stability and accuracy.

  11. Carrier and photon dynamics in a topological insulator Bi2Te3/GaN type II staggered heterostructure

    Science.gov (United States)

    Chaturvedi, P.; Chouksey, S.; Banerjee, D.; Ganguly, S.; Saha, D.

    2015-11-01

    We have demonstrated a type-II band-aligned heterostructure between pulsed laser deposited topological insulator bismuth telluride and metal organic-chemical-vapour deposited GaN on a sapphire substrate. The heterostructure shows a large valence band-offset of 3.27 eV as determined from x-ray photoelectron spectroscopy, which is close to the bandgap of GaN (3.4 eV). Further investigation using x-ray diffraction, Raman spectroscopy, and energy-dispersive x-ray spectrum reveals the stoichiometric and material properties of bismuth telluride on GaN. Steady state photon emission from GaN is found to be modulated by the charge transfer process due to diffusion across the junction. The time constant involved with the charge transfer process is found to be 0.6 ns by transient absorption spectroscopy. The heterostructure can be used for designing devices with different functionalities and improving the performance of the existing devices on GaN.

  12. Variable volume combustor

    Science.gov (United States)

    Ostebee, Heath Michael; Ziminsky, Willy Steve; Johnson, Thomas Edward; Keener, Christopher Paul

    2017-01-17

    The present application provides a variable volume combustor for use with a gas turbine engine. The variable volume combustor may include a liner, a number of micro-mixer fuel nozzles positioned within the liner, and a linear actuator so as to maneuver the micro-mixer fuel nozzles axially along the liner.

  13. Unsteady Reynolds Averaged Navier-Stokes and Large Eddy Simulations of Flows across Staggered Tube Bundle for a VHTR Lower Plenum Design

    International Nuclear Information System (INIS)

    Choi, Hyeon Kyeong; Park, Jong Woon

    2013-01-01

    In this work, behavior of unsteady and oscillating flow through a typical tube bundle array are analyzed by unsteady computations: 2D unsteady Reynolds averaged Navier-Stokes (URANS) and 3D Large Eddy Simulation (LES) and the results are compared with existing experimental data. In order to confirm appropriateness and limitations of CFD applications in the Korean VHTR design, two types of unsteady computations are performed such as 2D unsteady Reynolds averaged Navier-Stokes (URANS) and 3D Large Eddy Simulation (LES) for the existing tube bundle array. The velocity component profiles are compared with the experimental data and it is concluded that the URANS with the standard k-ω model is reasonably appropriate for cost-effective VHTR lower plenum analysis. Nevertheless, if more accurate results are needed, the LES-Smagorinsky computation is recommended considering limitations in the time averaged RANS in capturing small eddies

  14. Variable volume combustor with aerodynamic support struts

    Science.gov (United States)

    Ostebee, Heath Michael; Johnson, Thomas Edward; Stewart, Jason Thurman; Keener, Christopher Paul

    2017-03-07

    The present application provides a combustor for use with a gas turbine engine. The combustor may include a number of micro-mixer fuel nozzles and a fuel injection system for providing a flow of fuel to the micro-mixer fuel nozzles. The fuel injection system may include a number of support struts supporting the fuel nozzles and providing the flow of fuel therethrough. The support struts may include an aerodynamic contoured shape so as to distribute evenly a flow of air to the micro-mixer fuel nozzles.

  15. Variable volume combustor with aerodynamic fuel flanges for nozzle mounting

    Science.gov (United States)

    McConnaughhay, Johnie Franklin; Keener, Christopher Paul; Johnson, Thomas Edward; Ostebee, Heath Michael

    2016-09-20

    The present application provides a combustor for use with a gas turbine engine. The combustor may include a number of micro-mixer fuel nozzles and a fuel injection system for providing a flow of fuel to the micro-mixer fuel nozzles. The fuel injection system may include a number of support struts supporting the fuel nozzles and for providing the flow of fuel therethrough. The fuel injection system also may include a number of aerodynamic fuel flanges connecting the micro-mixer fuel nozzles and the support struts.

  16. SPECTRAL ANALYSIS OF GAS BEARING SYSTEMS FOR STABILITY STUDIES

    Science.gov (United States)

    latter case is given in terms of a herringbone-grooved journal bearing . This method of stability analysis is applicable to both thrust and journal bearings for both whirl and pneumatic-hammer instabilities.

  17. Variable volume combustor with an air bypass system

    Science.gov (United States)

    Johnson, Thomas Edward; Ziminsky, Willy Steve; Ostebee, Heath Michael; Keener, Christopher Paul

    2017-02-07

    The present application provides a combustor for use with flow of fuel and a flow of air in a gas turbine engine. The combustor may include a number of micro-mixer fuel nozzles positioned within a liner and an air bypass system position about the liner. The air bypass system variably allows a bypass portion of the flow of air to bypass the micro-mixer fuel nozzles.

  18. Tomography assessment of lung hyper inflation areas within cats in a pressure controlled ventilation staggered; Avaliacao tomografica das areas de de hiperinsuflacao pulmonar em gatos submetidos a ventilacao controlada a pressao escalonada

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Alessandro Rodrigues de Carvalho, E-mail: doutorevet@hotmail.com [Universidade de Sao Paulo (FM/USP), SP (Brazil). Faculdade de Medicina. Programa de Anestesiologia; Fantoni, Denise Tabacchi; Ambrosio, Aline Magalhaes [Universidade de Sao Paulo (FMVZ/USP), SP (Brazil). Faculdade de Medicina Veterinaria e Zootecnia; Santos, Jaqueline Franca dos; Villamizar, Lenin Arturo [Universidade de Sao Paulo (FMVZ/USP), SP (Brazil). Faculdade de Medicina Veterinaria e Zootecnia. Programa de Cirurgia; Pinto, Ana Carolina Brandao de Campos Fonseca [Universidade de Sao Paulo (USP), SP (Brazil). Faculdade de Medicina Veterinaria e Zootecnia. Disciplina de Diagnostico por Imagem; Martins, Thiago do Amaral [UFAPE Vet Intenziv, Itapecerica da Serra, SP (Brazil); Malbouisson, Luis Marcelo Sa [Universidade de Sao Paulo (HC/USP), SP (Brazil). Faculdade de Medicina. UTI Anestesiologica

    2012-07-01

    Mechanical ventilation is essential for oxygen supply during anesthesia. Some strategies are related to lung injury associated with mechanical ventilation. 10 cats, 4±1 kg, 1-6 years old, induced and maintained with propofol (6mg/kg, 0,5mg/kg/min) placed in supine position, subjected to pressure controlled ventilation (PCV) in oxygen at 40% with 5cmH{sub 2}O peak pressure in 'ZEEP' for 20 minutes, rising in 2cmH{sub 2}O installments peak pressure every five minutes until it reached 15cmH{sub 2}O. Moments P5, P7, P9, P11, P13, P15. Respiratory rate and inspiratory time were held on 15 movements per minute and 1 second regardless their EtCO{sub 2}. Muscle relaxation achieved by rocuronium bollus (1mg/kg/IV). Immediately, at each increase on pressure was performed a 4 seconds' inspiratory pause to allow the five millimeters CT slice of diaphragmatic region followed by hemogasometric and cardiorespiratory variables collected. P5 had the smallest hyperinflated area (3,24±4,02) Compared to other moments. P5 blood gases showed acidaemia (7,257±0,08) for mild respiratory acidosis (45±9.2) with good oxygenation (178±40.8mmHg) compared to other times which obtained reduction of CO{sub 2} and an increased pH. As the increase in peak pressure was observed increased distension of the lung parenchyma, a fact related to possible risk of lung injury in prolonged periods. 5cmH{sub 2}O pressure was demonstrated to be less harmful due to its lower hyper inflated areas that other moments, even with a low pH and high CO{sub 2}, being corrected by increasing respiratory rate.

  19. Process of nourishment staggered for elimination of nitrogen. Specific characteristics of the process. Strategies of control; Proceso de alimentacion escalonada para eliminacion de nitrogeno. Caracteristicas especificas del proceso. Estrategias de control

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigo, J. C.; Cortacans, J. A. [Infilco Espanola, s.a (Spain)

    2002-07-01

    This article illustrates the step fed activated sludge process advantages for biological nitrogen removal. This configuration, also known as ALP-HA (alternative phase step feed) process, reduces biological reactor volume, avoids internal sludge recycling and optimizes organic matter consumption for denitrification. Besides, it is offered the possibility to work with a calibrated specific model as a tool for the evaluation, design and operation of the process. To end up, some efficient operation strategies for the three-step ALPHA process in denitrification-nitrification reactors are proposed. (Author) 13 refs.

  20. Development and integration of a scalable low NOx combustion chamber for a hydrogen-fueled aerogas turbine

    Science.gov (United States)

    Boerner, S.; Funke, H. H.-W.; Hendrick, P.; Recker, E.; Elsing, R.

    2013-03-01

    The usage of alternative fuels in aircraft industry plays an important role of current aero engine research and development processes. The micromix burning principle allows a secure and low NOx combustion of gaseous hydrogen. The combustion principle is based on the fluid phenomenon of jet in cross flow and achieves a significant lowering in NOx formation by using multiple miniaturized flames. The paper highlights the development and the integration of a combustion chamber, based on the micromix combustion principle, into an Auxiliary Power Unit (APU) GTCP 36-300 with regard to the necessary modifications on the gas turbine and on the engine controller.

  1. Combustor nozzles in gas turbine engines

    Science.gov (United States)

    Johnson, Thomas Edward; Keener, Christopher Paul; Stewart, Jason Thurman; Ostebee, Heath Michael

    2017-09-12

    A micro-mixer nozzle for use in a combustor of a combustion turbine engine, the micro-mixer nozzle including: a fuel plenum defined by a shroud wall connecting a periphery of a forward tube sheet to a periphery of an aft tubesheet; a plurality of mixing tubes extending across the fuel plenum for mixing a supply of compressed air and fuel, each of the mixing tubes forming a passageway between an inlet formed through the forward tubesheet and an outlet formed through the aft tubesheet; and a wall mixing tube formed in the shroud wall.

  2. Spatiotemporal resonances in mixing of open viscous fluids

    DEFF Research Database (Denmark)

    Okkels, Fridolin; Tabeling, Patrick

    2004-01-01

    In this Letter, we reveal a new dynamical phenomenon, called "spatiotemporal resonance," which is expected to take place in a broad range of viscous, periodically forced, open systems. The observation originates from a numerical and theoretical analysis of a micromixer, and is supported by prelim...

  3. Fluid manipulation on the micro-scale: Basics of fluid behavior in microfluidics

    Czech Academy of Sciences Publication Activity Database

    Novotný, Jakub; Foret, František

    2017-01-01

    Roč. 40, č. 1 (2017), s. 383-394 ISSN 1615-9306 R&D Projects: GA ČR(CZ) GA15-15479S Institutional support: RVO:68081715 Keywords : microfluidics * micro-mixers * surface effects Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 2.557, year: 2016

  4. Enzyme Hydrolysis of Soybean Oil in a Slug Flow Microsystem

    Czech Academy of Sciences Publication Activity Database

    Čech, J.; Schrott, W.; Slouka, Z.; Přibyl, M.; Brož, M.; Kuncová, Gabriela; Šnita, D.

    2012-01-01

    Roč. 67, AUG 15 (2012), s. 194-202 ISSN 1369-703X R&D Projects: GA MŠk ME 892 Institutional support: RVO:67985858 Keywords : lipase * microemulsion * micromixing Subject RIV: EI - Biotechnology ; Bionics Impact factor: 2.579, year: 2012

  5. Lab-on-a-Chip: Frontier Science in the Classroom

    Science.gov (United States)

    Wietsma, Jan Jaap; van der Veen, Jan T.; Buesink, Wilfred; van den Berg, Albert; Odijk, Mathieu

    2018-01-01

    Lab-on-a-chip technology is brought into the classroom through development of a lesson series with hands-on practicals. Students can discover the principles of microfluidics with different practicals covering laminar flow, micromixing, and droplet generation, as well as trapping and counting beads. A quite affordable novel production technique…

  6. Oxidation and adduct formation of xenobiotics in a microfluidic electrochemical cell with boron doped diamond electrodes and an integrated passive gradient rotation mixer

    NARCIS (Netherlands)

    van den Brink, Floris Teunis Gerardus; Wigger, Tina; Ma, Liwei; Odijk, Mathieu; Olthuis, Wouter; Karst, U.; van den Berg, Albert

    2016-01-01

    Reactive xenobiotic metabolites and their adduct formation with biomolecules such as proteins are important to study as they can be detrimental to human health. Here, we present a microfluidic electrochemical cell with integrated micromixer to study phase I and phase II metabolism as well as protein

  7. Low cost lab-on-a-chip prototyping with a consumer grade 3D printer.

    Science.gov (United States)

    Comina, Germán; Suska, Anke; Filippini, Daniel

    2014-08-21

    Versatile prototyping of 3D printed lab-on-a-chip devices, supporting different forms of sample delivery, transport, functionalization and readout, is demonstrated with a consumer grade printer, which centralizes all critical fabrication tasks. Devices cost 0.57US$ and are demonstrated in chemical sensing and micromixing examples, which exploit established principles from reference technologies.

  8. Variable volume combustor with a conical liner support

    Science.gov (United States)

    Johnson, Thomas Edward; McConnaughhay, Johnie Franklin; Keener, Chrisophter Paul; Ostebee, Heath Michael

    2017-06-27

    The present application provides a variable volume combustor for use with a gas turbine engine. The variable volume combustor may include a liner, a number of micro-mixer fuel nozzles positioned within the liner, and a conical liner support supporting the liner.

  9. Lab-on-a-Chip : Frontier Science in the Classroom

    NARCIS (Netherlands)

    Wietsma, Jan Jaap; Van Der Veen, Jan T.; Buesink, Wilfred; Van Den Berg, Albert; Odijk, Mathieu

    2018-01-01

    Lab-on-a-chip technology is brought into the classroom through development of a lesson series with hands-on practicals. Students can discover the principles of microfluidics with different practicals covering laminar flow, micromixing, and droplet generation, as well as trapping and counting beads.

  10. Unravelling the Domain Structures in GeTe and LaAlO3

    NARCIS (Netherlands)

    Vermeulen, Paul A.; Kumar, Anil; ten Brink, Gert H.; Blake, Graeme R.; Kooi, Bart J.

    2016-01-01

    To resolve the controversy in the literature, we studied the extensively twinned domain structure of ferroelectric germanium telluride (GeTe) to formulate a comprehensive three-dimensional domain description. The observed herringbone-domain structure arises due to the displacive phase transformation

  11. Crystal structure of 2,2′-bipyrrole

    Directory of Open Access Journals (Sweden)

    Christopher A. Michaels

    2017-10-01

    Full Text Available The complete molecule of the title compound, C8H8N2, is generated by a crystallographic center of symmetry. In the crystal, short N—H...π [H...π = 2.499 (19 Å] interactions link the molecules into a herringbone structure.

  12. Sedimentary structures of tidal flats

    Indian Academy of Sciences (India)

    Sedimentary structures of some coastal tropical tidal flats of the east coast of India, and inner estuarine tidal point bars located at 30 to 50 kilometers inland from the coast, have been extensively studied under varying seasonal conditions. The results reveal that physical features such as flaser bedding, herringbone ...

  13. Attribute of trace fossils of Laisong flysch sediments, Manipur, India

    Indian Academy of Sciences (India)

    The above-mentioned ichnofacies are found associated with sedimentary structures such as large sole marks, parallel laminations, massive and structureless beds, rip-up clasts, etc., which are characteristics of submarine fan deposits below the storm wave base and current ripples, herringbone structures, hummocky cross ...

  14. Micro- and nanoflows modeling and experiments

    CERN Document Server

    Rudyak, Valery Ya; Maslov, Anatoly A; Minakov, Andrey V; Mironov, Sergey G

    2018-01-01

    This book describes physical, mathematical and experimental methods to model flows in micro- and nanofluidic devices. It takes in consideration flows in channels with a characteristic size between several hundreds of micrometers to several nanometers. Methods based on solving kinetic equations, coupled kinetic-hydrodynamic description, and molecular dynamics method are used. Based on detailed measurements of pressure distributions along the straight and bent microchannels, the hydraulic resistance coefficients are refined. Flows of disperse fluids (including disperse nanofluids) are considered in detail. Results of hydrodynamic modeling of the simplest micromixers are reported. Mixing of fluids in a Y-type and T-type micromixers is considered. The authors present a systematic study of jet flows, jets structure and laminar-turbulent transition. The influence of sound on the microjet structure is considered. New phenomena associated with turbulization and relaminarization of the mixing layer of microjets are di...

  15. One-pot synthesis of graphene oxide sheets and graphene oxide quantum dots from graphite nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Abdul Rashid, Suraya, E-mail: suraya-ar@upm.edu.my; Mohd Zobir, Syazwan Afif [Universiti Putra Malaysia, Materials Processing and Technology Laboratory, Nanomaterials and Nanotechnology Group, Institute of Advanced Technology (Malaysia); Krishnan, Shutesh; Hassan, Mohd Murshid [Graphene Nanochem Sdn. Bhd., Level 9, WORK@Clearwater (Malaysia); Lim, Hong Ngee [Universiti Putra Malaysia, UPM, Department of Chemistry, Faculty of Science (Malaysia)

    2015-05-15

    A one-pot synthesis of graphene oxide (GO) sheets and GO quantum dots using graphite nanofibers (GNF) as starting material is reported. Two types of GNF starting materials, namely herringbone and platelet structures, were used. HRTEM revealed that platelet GNF produces quantum dots typically less than 10 nm in size while herringbone GNF produces relatively larger GO sheets. SAED patterns indicate that the produced GO sheets have a hexagonal crystal structure. UV–Vis, PL, XPS, and Raman show salient differences between the produced GO nanostructures which correlate well with the morphological analysis. Unlike the GO sheets, the GO quantum dots are photoluminescent. The difference in PL properties was attributed to the higher oxygen content in GO quantum dots which were shown by XPS. The results offer a new insight to the importance of starting material in the synthesis of graphene nanostructures.

  16. Microsecond time-scale kinetics of transient biochemical reactions

    NARCIS (Netherlands)

    Mitic, S.; Strampraad, M.J.F.; Hagen, W.R.; de Vries, S.

    2017-01-01

    To afford mechanistic studies in enzyme kinetics and protein folding in the microsecond time domain we have developed a continuous-flow microsecond time-scale mixing instrument with an unprecedented dead-time of 3.8 ± 0.3 μs. The instrument employs a micro-mixer with a mixing time of 2.7 μs

  17. Study of a Multi-Phase Hybrid Heat Exchanger-Reactor (HEX Reactor): Part 2 - Numerical Prediction of Thermal Performance (Postprint)

    Science.gov (United States)

    2014-01-01

    Santacesaria et al. [2] reported higher yields of biodiesel at relatively low Re, which they credited to strong localized micromixing and turbulence. Edge et...corrugated heat transfer plates which are separated by gaskets. The corrugations are aligned in a repeating series of chevrons toApproved for public release...industrial applications [10]. The treatment of individual channels as separate submodels (Fig. 3) also allows for non-idealities seen in real heat

  18. Plate heat exchangers in the power plant industry

    International Nuclear Information System (INIS)

    Wersel, M.; Ridell, B.

    1984-01-01

    An increase in heat transfer and stability, small investment, high flexibility, easy maintenance and corrosion resistance are obtained by the design and construction of plate heat exchangers and by the introduction of the herringbone pattern. The plate heat exchanger can be used in nearly 90% of all secondary circuits in powerstations. Examples of its installation are the WYLFA, GENTILLY, RINGHALS and TVO Finland nuclear power-stations. (DG) [de

  19. Study of a high gain microchannel plate photomultiplier having low statistical gain fluctuations

    International Nuclear Information System (INIS)

    Audier, M.

    1980-12-01

    A new photomultiplier configuration which synthesizes the performances of several models is proposed. The principles of microchannel plate photomultipliers are reviewed. The physical phenomena which limit the electron multiplication process in a microchannel and the detection efficiency of the microchannel plates are investigated. The operation of a herring-bone pattern device and of a system of two microchannel plate photomultipliers are described and characterized [fr

  20. A novel passive microfluidic device for preprocessing whole blood for point of care diagnostics

    DEFF Research Database (Denmark)

    Shah, Pranjul Jaykumar; Dimaki, Maria; Svendsen, Winnie Edith

    2009-01-01

    integration of electrodes, traps, reservoirs, heaters, etc which is often difficult at microscale [1 – 4]. On the other hand, FACSlyse protocol uses only osmotic pressure to lyse erythrocytes allowing further isolation of leukocytes. This motivated us to develop a novel herringbone based lyser which works...... on the principle of mixing whole blood with pure water in time controlled manner to lyse erythrocytes osmotically on a chip....

  1. A “twisted” microfluidic mixer suitable for a wide range of flow rate applications

    KAUST Repository

    Sivashankar, Shilpa

    2016-06-27

    This paper proposes a new “twisted” 3D microfluidic mixer fabricated by a laser writing/microfabrication technique. Effective and efficient mixing using the twisted micromixers can be obtained by combining two general chaotic mixing mechanisms: splitting/recombining and chaotic advection. The lamination of mixer units provides the splitting and recombination mechanism when the quadrant of circles is arranged in a two-layered serial arrangement of mixing units. The overall 3D path of the microchannel introduces the advection. An experimental investigation using chemical solutions revealed that these novel 3D passive microfluidic mixers were stable and could be operated at a wide range of flow rates. This micromixer finds application in the manipulation of tiny volumes of liquids that are crucial in diagnostics. The mixing performance was evaluated by dye visualization, and using a pH test that determined the chemical reaction of the solutions. A comparison of the tornado-mixer with this twisted micromixer was made to evaluate the efficiency of mixing. The efficiency of mixing was calculated within the channel by acquiring intensities using ImageJ software. Results suggested that efficient mixing can be obtained when more than 3 units were consecutively placed. The geometry of the device, which has a length of 30 mm, enables the device to be integrated with micro total analysis systems and other lab-on-chip devices.

  2. Factors That Impact Nurses’ Utilization of Electronic Mail (E-Mail).

    Science.gov (United States)

    1998-05-21

    e-mail (Hebda, Czar, & Mascara , 1998; Holtzclaw et al., 1993; Murray, 1996; Staggers, 1996). Staggers (1989) identified nurses as primary processors...pp. 247-274). St. Louis: Mosby-Year Book. Hebda, T., Czar, P., & Mascara , C. (1998). Handbook of informatics for nurses and health care

  3. Calculation of Core Damage Frequency for the Change of the Common Cause Failure Parameters According to the Testing Strategies

    International Nuclear Information System (INIS)

    Kang, Dae Il; Kim, Kil You; Jin, Young Ho; Kim, Tae Woon

    2011-01-01

    Common cause failure (CCF) probabilities are differently estimated according to testing strategies. There are two representative testing schemes; staggered testing and non-staggered testing schemes. For the cases where trains or channels of standby safety systems consisting of more than two redundant components are tested in a staggered manner, the standby safety components within a train can be tested simultaneously or consecutively. In this case, mixed testing scheme, staggered and non-staggered testing schemes, are used for testing the components. Kang et al. derived the formulas for the estimations of the CCF probabilities of the components under the mixed testing scheme. This paper presents the sensitivity study results on the core damage frequency (CDF) of the SMART (System-integrated Modular Advanced Reactor) for the changes of the CCF parameters according to the testing strategies

  4. Estimation of the common cause failure probabilities on the component group with mixed testing scheme

    International Nuclear Information System (INIS)

    Hwang, Meejeong; Kang, Dae Il

    2011-01-01

    Highlights: ► This paper presents a method to estimate the common cause failure probabilities on the common cause component group with mixed testing schemes. ► The CCF probabilities are dependent on the testing schemes such as staggered testing or non-staggered testing. ► There are many CCCGs with specific mixed testing schemes in real plant operation. ► Therefore, a general formula which is applicable to both alternate periodic testing scheme and train level mixed testing scheme was derived. - Abstract: This paper presents a method to estimate the common cause failure (CCF) probabilities on the common cause component group (CCCG) with mixed testing schemes such as the train level mixed testing scheme or the alternate periodic testing scheme. In the train level mixed testing scheme, the components are tested in a non-staggered way within the same train, but the components are tested in a staggered way between the trains. The alternate periodic testing scheme indicates that all components in the same CCCG are tested in a non-staggered way during the planned maintenance period, but they are tested in a staggered way during normal plant operation. Since the CCF probabilities are dependent on the testing schemes such as staggered testing or non-staggered testing, CCF estimators have two kinds of formulas in accordance with the testing schemes. Thus, there are general formulas to estimate the CCF probability on the staggered testing scheme and non-staggered testing scheme. However, in real plant operation, there are many CCCGs with specific mixed testing schemes. Recently, Barros () and Kang () proposed a CCF factor estimation method to reflect the alternate periodic testing scheme and the train level mixed testing scheme. In this paper, a general formula which is applicable to both the alternate periodic testing scheme and the train level mixed testing scheme was derived.

  5. Electrode alignment of transverse tripoles using a percutaneous triple-lead approach in spinal cord stimulation

    Science.gov (United States)

    Sankarasubramanian, V.; Buitenweg, J. R.; Holsheimer, J.; Veltink, P.

    2011-02-01

    The aim of this modeling study is to determine the influence of electrode alignment of transverse tripoles on the paresthesia coverage of the pain area in spinal cord stimulation, using a percutaneous triple-lead approach. Transverse tripoles, comprising a central cathode and two lateral anodes, were modeled on the low-thoracic vertebral region (T10-T12) using percutaneous triple-lead configurations, with the center lead on the spinal cord midline. The triple leads were oriented both aligned and staggered. In the staggered configuration, the anodes were offset either caudally (caudally staggered) or rostrally (rostrally staggered) with respect to the midline cathode. The transverse tripolar field steering with the aligned and staggered configurations enabled the estimation of dorsal column fiber thresholds (IDC) and dorsal root fiber thresholds (IDR) at various anodal current ratios. IDC and IDR were considerably higher for the aligned transverse tripoles as compared to the staggered transverse tripoles. The aligned transverse tripoles facilitated deeper penetration into the medial dorsal columns (DCs). The staggered transverse tripoles always enabled broad and bilateral DC activation, at the expense of mediolateral steerability. The largest DC recruited area was obtained with the rostrally staggered transverse tripole. Transverse tripolar geometries, using percutaneous leads, allow for selective targeting of either medial or lateral DC fibers, if and only if the transverse tripole is aligned. Steering of anodal currents between the lateral leads of the staggered transverse tripoles cannot target medially confined populations of DC fibers in the spinal cord. An aligned transverse tripolar configuration is strongly recommended, because of its ability to provide more post-operative flexibility than other configurations.

  6. Effects of Composition of Alginate-Polyethylene Glycol Microcapsules and Transplant Site on Encapsulated Islet Graft Outcomes in Mice.

    Science.gov (United States)

    Villa, Chiara; Manzoli, Vita; Abreu, Maria M; Verheyen, Connor A; Seskin, Michael; Najjar, Mejdi; Molano, R Damaris; Torrente, Yvan; Ricordi, Camillo; Tomei, Alice A

    2017-05-01

    Understanding the effects of capsule composition and transplantation site on graft outcomes of encapsulated islets will aid in the development of more effective strategies for islet transplantation without immunosuppression. Here, we evaluated the effects of transplanting alginate (ALG)-based microcapsules (Micro) in the confined and well-vascularized epididymal fat pad (EFP) site, a model of the human omentum, as opposed to free-floating in the intraperitoneal cavity (IP) in mice. We also examined the effects of reinforcing ALG with polyethylene glycol (PEG). To allow transplantation in the EFP site, we minimized capsule size to 500 ± 17 μm. Unlike ALG, PEG resists osmotic stress, hence we generated hybrid microcapsules by mixing PEG and ALG (MicroMix) or by coating ALG capsules with a 15 ± 2 μm PEG layer (Double). We found improved engraftment of fully allogeneic BALB/c islets in Micro capsules transplanted in the EFP (median reversal time [MRT], 1 day) versus the IP site (MRT, 5 days; P < 0.01) in diabetic C57BL/6 mice and of Micro encapsulated (MRT, 8 days) versus naked (MRT, 36 days; P < 0.01) baboon islets transplanted in the EFP site. Although in vitro viability and functionality of islets within MicroMix and Double capsules were comparable to Micro, addition of PEG to ALG in MicroMix capsules improved engraftment of allogeneic islets in the IP site, but resulted deleterious in the EFP site, probably due to lower biocompatibility. Our results suggest that capsule composition and transplant site affect graft outcomes through their effects on nutrient availability, capsule stability, and biocompatibility.

  7. Dispersion of a Passive Scalar Fluctuating Plume in a Turbulent Boundary Layer. Part III: Stochastic Modelling

    Science.gov (United States)

    Marro, Massimo; Salizzoni, Pietro; Soulhac, Lionel; Cassiani, Massimo

    2018-01-01

    We analyze the reliability of the Lagrangian stochastic micromixing method in predicting higher-order statistics of the passive scalar concentration induced by an elevated source (of varying diameter) placed in a turbulent boundary layer. To that purpose we analyze two different modelling approaches by testing their results against the wind-tunnel measurements discussed in Part I (Nironi et al., Boundary-Layer Meteorology, 2015, Vol. 156, 415-446). The first is a probability density function (PDF) micromixing model that simulates the effects of the molecular diffusivity on the concentration fluctuations by taking into account the background particles. The second is a new model, named VPΓ, conceived in order to minimize the computational costs. This is based on the volumetric particle approach providing estimates of the first two concentration moments with no need for the simulation of the background particles. In this second approach, higher-order moments are computed based on the estimates of these two moments and under the assumption that the concentration PDF is a Gamma distribution. The comparisons concern the spatial distribution of the first four moments of the concentration and the evolution of the PDF along the plume centreline. The novelty of this work is twofold: (i) we perform a systematic comparison of the results of micro-mixing Lagrangian models against experiments providing profiles of the first four moments of the concentration within an inhomogeneous and anisotropic turbulent flow, and (ii) we show the reliability of the VPΓ model as an operational tool for the prediction of the PDF of the concentration.

  8. A turbulent time scale based k–ε model for probability density function modeling of turbulence/chemistry interactions: Application to HCCI combustion

    International Nuclear Information System (INIS)

    Maroteaux, Fadila; Pommier, Pierre-Lin

    2013-01-01

    Highlights: ► Turbulent time evolution is introduced in stochastic modeling approach. ► The particles number is optimized trough a restricted initial distribution. ► The initial distribution amplitude is modeled by magnitude of turbulence field. -- Abstract: Homogenous Charge Compression Ignition (HCCI) engine technology is known as an alternative to reduce NO x and particulate matter (PM) emissions. As shown by several experimental studies published in the literature, the ideally homogeneous mixture charge becomes stratified in composition and temperature, and turbulent mixing is found to play an important role in controlling the combustion progress. In a previous study, an IEM model (Interaction by Exchange with the Mean) has been used to describe the micromixing in a stochastic reactor model that simulates the HCCI process. The IEM model is a deterministic model, based on the principle that the scalar value approaches the mean value over the entire volume with a characteristic mixing time. In this previous model, the turbulent time scale was treated as a fixed parameter. The present study focuses on the development of a micro-mixing time model, in order to take into account the physical phenomena it stands for. For that purpose, a (k–ε) model is used to express this micro-mixing time model. The turbulence model used here is based on zero dimensional energy cascade applied during the compression and the expansion cycle; mean kinetic energy is converted to turbulent kinetic energy. Turbulent kinetic energy is converted to heat through viscous dissipation. Besides, in this study a relation to calculate the initial heterogeneities amplitude is proposed. The comparison of simulation results against experimental data shows overall satisfactory agreement at variable turbulent time scale

  9. Microfluidic active mixers employing ultra-high aspect-ratio rare-earth magnetic nano-composite polymer artificial cilia

    International Nuclear Information System (INIS)

    Rahbar, Mona; Gray, Bonnie L; Shannon, Lesley

    2014-01-01

    We present a new micromixer based on highly magnetic, flexible, high aspect-ratio, artificial cilia that are fabricated as individual micromixer elements or in arrays for improved mixing performance. These new cilia enable high efficiency, fast mixing in a microchamber, and are controlled by small electromagnetic fields. The artificial cilia are fabricated using a new micromolding process for nano-composite polymers. Cilia fibers with aspect-ratios as high as 8:0.13 demonstrate the fabrication technique's capability in creating ultra-high aspect-ratio microstructures. Cilia, which are realized in polydimethylsiloxane doped with rare-earth magnetic powder, are magnetized to produce permanent magnetic structures with bidirectional deflection capabilities, making them highly suitable as mixers controlled by electromagnetic fields. Due to the high magnetization level of the polarized nano-composite polymer, we are able to use miniature electromagnets providing relatively small magnetic fields of 1.1 to 7 mT to actuate the cilia microstructures over a very wide motion range. Mixing performances of a single cilium, as well as different arrays of multiple cilia ranging from 2 to 8 per reaction chamber, are characterized and compared with passive diffusion mixing performance. The mixer cilia are actuated at different amplitudes and frequencies to optimize mixing performance. We demonstrate that more than 85% of the total volume of the reaction chamber is fully mixed after 3.5 min using a single cilium mixer at 7 mT compared with only 20% of the total volume mixed with passive diffusion. The time to achieve over 85% mixing is further reduced to 70 s using an array of eight cilia microstructures. The novel microfabrication technique and use of rare-earth permanently-magnetizable nano-composite polymers in mixer applications has not been reported elsewhere by other researchers. We further demonstrate improved mixing over other cilia micromixers as enabled by the high

  10. Structure of zone-cast HBC-C12H25 films

    DEFF Research Database (Denmark)

    Breiby, Dag Werner; Bunk, Oliver; Pisula, W.

    2005-01-01

    The structure of a thin zone-cast film of the hexa-n-dodecyl-substituted hexa-peri-benzocoronene (HBC) has been investigated using grazing incidence X-ray diffraction. A model with an orthorhombic unit cell containing two molecules accounts well for the observations. The molecules are arranged...... in a "herringbone" structure resembling the packing observed for unsubstituted HBC. The molecular disk planes are oriented perpendicularly to the substrate, rotated by approximately 39 degrees about the film normal. The relatively long side chains of dodecyl were found to be in an ordered interdigitated state...

  11. Shear-induced particle migration in one-, two-, and three-dimensional flows

    Science.gov (United States)

    Gao, C.; Gilchrist, J. F.

    2008-02-01

    We investigate the segregation resulting from the competition between advection and shear-induced migration of suspensions in steady open flows. Herringbone channels form a concentration profile deviating from the particle focusing found in straight channels. Transients can result from a buckling instability during the onset of migration when particle-depleted fluid is injected into particle-rich fluid. In chaotic flows, the better mixing found at low bulk volume fraction is not seen at higher bulk volume fraction. Thus, the ability of static mixers to reduce the effects of shear-induced migration is significantly limited.

  12. Mapping the Diffusion Potential of a Reconstructed Au(111) Surface at Nanometer Scale with 2D Molecular Gas

    International Nuclear Information System (INIS)

    Yan Shi-Chao; Xie Nan; Gong Hui-Qi; Guo Yang; Shan Xin-Yan; Lu Xing-Hua; Sun Qian

    2012-01-01

    The adsorption and diffusion behaviors of benzene molecules on an Au(111) surface are investigated by low-temperature scanning tunneling microscopy. A herringbone surface reconstruction of the Au(111) surface is imaged with atomic resolution, and significantly different behaviors are observed for benzene molecules adsorbed on step edges and terraces. The electric field induced modification in the molecular diffusion potential is revealed with a 2D molecular gas model, and a new method is developed to map the diffusion potential over the reconstructed Au(111) surface at the nanometer scale. (condensed matter: structure, mechanical and thermal properties)

  13. Crystal structure of dichloridobis(methyl isonicotinate-κNcopper(II

    Directory of Open Access Journals (Sweden)

    Elaheh Ahadi

    2015-05-01

    Full Text Available In the title compound, [CuCl2(C7H7NO22], the square-planar-coordinated CuII ion lies on a centre of symmetry and is bonded to two monodentate methylisonicotinate ligands through their N atoms and by two chloride ligands. The molecules pack in a herringbone pattern. Perpendicular to [100] there are weak intermolecular C—H...Cl and C—H...O contacts. Along [100] there are infinite chains of edge-sharing octahedra linked through the chlorido ligands

  14. EC-STM study of the initial stages of the electrochemical Au(1 1 1)-Cd alloy formation

    DEFF Research Database (Denmark)

    Schlaup, Christian Georg; Horch, Sebastian

    2014-01-01

    We have studied the formation of an Au(1 1 1)-Cd alloy in a H2SO4 electrolyte by means of electrochemical STM (EC-STM). To this end, we first characterized the underpotential deposited (upd) Cd overlayers on Au(1 1 1) electrodes. We confirmed the existence of two upd phases on the reconstructed A...... with the pattern of the Au(1 1 1) "herringbone" reconstruction. This Au-Cd alloy increases the overpotential for the hydrogen evolution reaction (HER) by about 130 mV....

  15. The historical development of heat transfer surfaces for gas-cooled reactors analysed with a simple criterion

    International Nuclear Information System (INIS)

    Leslie, D.C.

    1980-01-01

    The evolution of finned heat transfer surfaces for gas-cooled reactors, from longitudinal through transverse to the sophisticated helical polyzonal and herring-bone fins, is described, and their merits are compared using a simple criterion of heat transfer efficiency. These fins cannot be used in AGR's because of the high neutron absorption and low thermal conductivity of stainless steel, and artificial roughening in the form of ribbing is used instead; the same criterion can be applied to this type of surface. The interest of the material is largely historical. (author)

  16. N-Oxide-N-oxide interactions and Cl...Cl halogen bonds in pentachloropyridine N-oxide: the many-body approach to interactions in the crystal state.

    Science.gov (United States)

    Wzgarda-Raj, Kinga; Rybarczyk-Pirek, Agnieszka J; Wojtulewski, Sławomir; Palusiak, Marcin

    2018-02-01

    Pentachloropyridine N-oxide, C 5 Cl 5 NO, crystallizes in the monoclinic space group P2 1 /c. In the crystal structure, molecules are linked by C-Cl...Cl halogen bonds into infinite ribbons extending along the crystallographic [100] direction. These molecular aggregates are further stabilized by very short intermolecular N-oxide-N-oxide interactions into herringbone motifs. Computations based on quantum chemistry methods allowed for a more detailed description of the N-oxide-N-oxide interactions and Cl...Cl halogen bonds. For this purpose, Hirshfeld surface analysis and the many-body approach to interaction energy were applied.

  17. Overlayer structure of subphthalocyanine derivative deposited on Au (111) surface by a spray-jet technique

    International Nuclear Information System (INIS)

    Suzuki, Hitoshi; Yamada, Toshiki; Miki, Hideki; Mashiko, Shinro

    2006-01-01

    A new spray-jet technique was used to deposit subphthalocyanine derivative (chloro[tri-tert-butyl subphthalocyaninato]boron (TBSubPc)) on Au (111) surface in an ultra-high vacuum (UHV) chamber. The deposited molecular overlayer was observed with UHV scanning tunneling microscopy (STM) at 77 K. The STM images showed that TBSubPc molecules formed a stripe pattern with regular spacing, indicating that they preferentially adsorbed along the herringbone structure of the Au (111) surface. This behavior was very similar to that of TBSubPc molecules deposited by thermal evaporation

  18. Snap-Through Instability of Graphene on Substrates

    Directory of Open Access Journals (Sweden)

    Li Teng

    2009-01-01

    Full Text Available Abstract We determine the graphene morphology regulated by substrates with herringbone and checkerboard surface corrugations. As the graphene–substrate interfacial bonding energy and the substrate surface roughness vary, the graphene morphology snaps between two distinct states: (1 closely conforming to the substrate and (2 remaining nearly flat on the substrate. Since the graphene morphology is strongly tied to the electronic properties of graphene, such a snap-through instability of graphene morphology can lead to desirable graphene electronic properties that could potentially enable graphene-based functional electronic components (e.g. nano-switches.

  19. Analysis of Depth of Shade on Mercerized and Unmercerized Fabric among Different Woven Fabric Structures

    OpenAIRE

    Alam, Md Shamim

    2016-01-01

    The main objective of this paper is to analyze and compare the color strengths of mercerized and unmercerized fabric among different fabric structures. In this research work Remazol reactive dye and three types of woven fabrics were used such as 20⁎20 sheeting, 30⁎30 sheeting, and herringbone. Spectrophotometer was used to find out the amount of dye which is fixed in the fabrics after soap wash. Three different woven fabrics were dyed with reactive dye (Remazol Red, Remazol Yellow, and Remazo...

  20. [The formative background of the philosophy on division of the human body circumference based on the figure of Taisu's Nine Zones and Eight Winds].

    Science.gov (United States)

    Son, Kizen

    2011-11-01

    The figure of Nine Zone and Eight Winds is the only figure in Huangdi Neijing·Taisu. Recording in Lingshu·Jiuzhenlun identifies the origin of the division of the human body circumference. The human body division theory was consistent with archaeological discoveries of Shengui (sacred turtle) divinations and Renzitu (herringbone figure). By matching organs, and body surface with Ba Fang (eight directions), Ba Jie (eight solar terms) and Ba Feng (eight kinds of winds from eight directions), the figure of Nine Zone and Eight Winds connected time, space and human body, and the framework of the theory of the human body formed.

  1. meso-Substituted bisanthenes as soluble and stable near-infrared dyes

    KAUST Repository

    Li, Jinling

    2010-02-05

    (Chemical Equation Presented) Three meso-substituted bisanthenes, 4-6, were prepared in a short synthetic route from the bisanthenequinone. They exhibit largely improved stability and solubility in comparison to the parent bisanthene. All of these compounds also show near-infrared (NIR) absorption and emission with high to moderate fluorescence quantum yields. Amphoteric redox behavior was observed for 4-6 by cyclic voltammetry, and these compounds can be reversibly oxidized and reduced into respective cationic and anionic species by both electrochemical and chemical processes. In addition, compound 5 adopts a herringbone π-stacking motif in the single crystal. © 2010 American Chemical Society.

  2. 4-Bromoselenoanisole

    Directory of Open Access Journals (Sweden)

    Henning Osholm Sørensen

    2009-07-01

    Full Text Available The title compound, 1-bromo-4-methylselenobenzene, C7H7BrSe, was prepared by methylation of 4-bromoselenophenolate with methyl iodide, and crystals suitable for structure determination were obtained by sublimation. The molecule is essentially planar; the Se—Me bond is rotated by only 2.59 (19° out of the least-squares plane of the benzene ring. The most pronounced intermolecular interactions are two hydrogen bonds of the type C—H...π, which determine a herring-bone pattern in the crystal packing.

  3. Parallel implicit Multigrid Method for Direct Numerical Simulation of Time-Dependent Compressible Turbulent Flow Around Flight Vehicles

    National Research Council Canada - National Science Library

    Liu, Chaoqun

    1999-01-01

    .... Four transitional stages are observed: the linear and weakly nonlinear growth, the appearance of staggered A-vortex patterns, the evolution of A-vortex into hairpin vortex, the breakdown of hairpin vortical structures...

  4. A synthesis report of purpose and need: assessment of event egress for Houston's Reliant Stadium.

    Science.gov (United States)

    2015-12-01

    Attendance at large arena events is increasing, as the seats are added, and ground level activities such as tailgating attract visitors not attending the game. Access is somewhat staggered as people choose their arrival times differently. However, th...

  5. Combination Classes and "Hora de comunicacion."

    Science.gov (United States)

    Eldredge, Dee L.

    1989-01-01

    Ways to combine small classes of higher education students studying Spanish at various levels are described, including judicious use of language laboratories, staggering of the different level groups, and rotation of activities geared toward students' individual proficiency levels. (CB)

  6. Tipping Point

    Medline Plus

    Full Text Available ... death electrical fall furniture head injury product safety television tipover tv Watch the video in Adobe Flash ... tv tip-overs. The force of a large television falling from tipping furniture can be staggering. A ...

  7. The environment within: how gut microbiota may influence metabolism and body composition

    NARCIS (Netherlands)

    Vrieze, A.; Holleman, F.; Zoetendal, E. G.; de Vos, W. M.; Hoekstra, J. B. L.; Nieuwdorp, M.

    2010-01-01

    Obesity, diabetes and consequently atherosclerotic vascular disease have become major health and public health issues worldwide. The increasing and staggering prevalence of obesity might not only be explained by nutritional habits or the reduction of energy expenditure through decreased physical

  8. Intelligent system for helping the development of production an recoverable reserves in fully developed oil fields in Colombia; Sistema inteligente ayuda a incrementar la produccion y reservas recuperables en campos maduros de Colombia

    Energy Technology Data Exchange (ETDEWEB)

    Soto B, Rodolfo; Bejarano, Aristobulo; Ferneynes, Heberth Ferneynes; Ardila, Juan Fernando [Ecopetrol S.A., Bogota (Colombia)]|[Instituto Colombiano del Petroleo, Bogota (Colombia)

    2000-07-01

    An intelligent system - Oil field Intelligence - have been developed as a engineering tool for improving the characterization of oil and gas reservoirs. The system integrates neural networks, main component analysis, staggering and generalization techniques, and a expertise module. (author)

  9. Bracken fern poisoning

    Science.gov (United States)

    Bracken fern (Pteridium aquilinum) has worldwide distribution and in some areas dominated plant communities replacing desirable forages. Poisoning is identified as enzootic hematuria, bright blindness, and bracken staggers. This chapter reviews updates new information on the plant, the various poi...

  10. Cardiovascular risk factors among the inhabitants of an urban Congolese community: results of the VITARAA Study

    Directory of Open Access Journals (Sweden)

    Pascal M. Bayauli

    2014-09-01

    Conclusion: Our findings highlight the staggering rates of cardiovascular risk factors in sub-Saharan Africa and underscore the pressing need to move their prevention and control higher on the political agenda.

  11. Streamlining Field Data Collection With Mobile Apps

    Science.gov (United States)

    Camp, Reid J.; Wheaton, Joseph M.

    2014-12-01

    Fieldwork is a major component of nearly every geoscience discipline. Over the past 3 decades, scientists have amassed an array of specialized instrumentation and equipment to help them measure and monitor a staggering assortment of geophysical phenomena.

  12. Handbook of Monte Carlo methods

    National Research Council Canada - National Science Library

    Kroese, Dirk P; Taimre, Thomas; Botev, Zdravko I

    2011-01-01

    ... in rapid succession, the staggering number of related techniques, ideas, concepts and algorithms makes it difficult to maintain an overall picture of the Monte Carlo approach. This book attempts to encapsulate the emerging dynamics of this field of study"--

  13. National Center on Family Homelessness

    Science.gov (United States)

    ... You are here Home National Center on Family Homelessness Center A staggering 2.5 million children are ... raise awareness of the current state of child homelessness in the United States, documents the number of ...

  14. Unlocking the secrets of the Universe

    CERN Multimedia

    Brady, M

    2002-01-01

    "In a staggering feat of engineering, Canadian scientists, working two kilometres underground with a giant sphere, are hunting for tiny solar particles to help answer an age-old question: How did the cosmos evolve?" (2 pages).

  15. Relevance of Army National Guard Infantry Units in the Force Structure and Their Role in Combat

    National Research Council Canada - National Science Library

    Harris, Brian

    2004-01-01

    ...% of a total force of 346,848 assigned. Such large numbers are staggering considering that National Guard infantry units are not being utilized according to their organization training and equipment...

  16. Numerical study of dense adjoint 2-color matter

    International Nuclear Information System (INIS)

    Hands, S.; Scorzato, L.; Oevers, M.

    2000-11-01

    We study the global symmetries of SU(2) gauge theory with N flavors of staggered fermions in the presence of a chemical potential. We motivate the special interest of the case N=1 (staggered) with fermions in the adjoint representation of the gauge group. We present results from numerical simulations with both hybrid Monte Carlo and the two-step multi-bosonic algorithm. (orig.)

  17. Prototyping chips in minutes: Direct Laser Plotting (DLP) of functional microfluidic structures

    KAUST Repository

    Wang, Limu

    2013-10-10

    We report a fast and simple prototyping method to fabricate polymer-based microfluidic chips using Direct Laser Plotting (DLP) technique, by which various functional micro-structures can be realized within minutes, in a mask-free and out-of-cleanroom fashion. A 2D Computer-Aid-Design (CAD) software was employed to layout the required micro-structures and micro-channels, a CO2 laser plotter was then used to construct the microstructures. The desired patterns can be plotted directly on PDMS substrates and bio-compatible polymer films by manipulating the strength and density of laser pulses. With the DLP technique, chip-embedded micro-electrodes, micro-mixers and 3D microfluidic chips with 5 layers, which normally require several days of work in a cleanroom facility, can be fabricated in minutes in common laboratory. This novel method can produce microfluidic channels with average feature size of 100 μm, while feature size of 50 μm or smaller is achievable by making use of the interference effect from laser impulsion. In this report, we present the optimized parameters for successful fabrication of 3D microchannels, micro-mixers and microfluidic chips for protein concentration measurements (Bovine Serum Albumine (BSA) test), and a novel procedure to pattern flexible embedding electrodes on PDMS-based microfluidic chips. DLP offers a convenient and low cost alternative to conventional microfluidic channel fabrication technique which relies on complicated and hazardous soft lithography process.

  18. Combination of microfluidic high-throughput production and parameter screening for efficient shaping of gold nanocubes using Dean-flow mixing.

    Science.gov (United States)

    Thiele, Matthias; Knauer, Andrea; Malsch, Daniéll; Csáki, Andrea; Henkel, Thomas; Köhler, J Michael; Fritzsche, Wolfgang

    2017-04-11

    Metal nanoparticles and their special optical properties, the so-called localized surface plasmon resonance (LSPR), facilitate many applications in various fields. Due to the strong dependency of the LSPR on particle geometry, their synthesis is a challenging and time-consuming procedure especially for non-spherical shapes. In contrast, micromixers offer new experimental approaches and therefore enable the simplification of several processes. By using a zigzag micromixer (Dean-Flow-Mixer, DFM) that induces Dean-flow secondary flow patterns, we theoretically and experimentally show the mixing efficiency. Thus, we highlight the advantages of using it in the multistep synthesis of Au nanoparticles. Based on a narrow size distribution of Au nanocubes and an increased yield in combination with higher reproducibility, we depict the need for and advantage of the DFM to control the incubation times during the growth process. We further show that, by using the DFM, easy and very fast Au nanocube edge length tuning (53 nm, 58 nm, 70 nm and 75 nm) is possible by simultaneously reducing the consumption of the materials by up to 95%. We finally demonstrate the versatile abilities by using the DFM for parameter screening on examples of different halides and accessible bromide in the growth solutions. Therefore, we highlight the optimal concentration for the different growth regimes and the influences on the Au nanoparticle morphology (spheres, cubes and rods) and their defined shaping.

  19. Analysis of Passive Mixing in a Serpentine Microchannel with Sinusoidal Side Walls

    Directory of Open Access Journals (Sweden)

    Muhammad Usman Javaid

    2017-12-01

    Full Text Available Sample mixing is difficult in microfluidic devices because of laminar flow. Micromixers are designed to ensure the optimal use of miniaturized devices. The present study aims to design a chaotic-advection-based passive micromixer with enhanced mixing efficiency. A serpentine-shaped microchannel with sinusoidal side walls was designed, and three cases, with amplitude to wavelength (A/λ ratios of 0.1, 0.15, and 0.2 were investigated. Numerical simulations were conducted using the Navier–Stokes equations, to determine the flow field. The flow was then coupled with the convection–diffusion equation to obtain the species concentration distribution. The mixing performance of sinusoidal walled channels was compared with that of a simple serpentine channel for Reynolds numbers ranging from 0.1 to 50. Secondary flows were observed at high Reynolds numbers that mixed the fluid streams. These flows were dominant in the proposed sinusoidal walled channels, thereby showing better mixing performance than the simple serpentine channel at similar or less mixing cost. Higher mixing efficiency was obtained by increasing the A/λ ratio.

  20. A Microfluidic Device for Continuous Sensing of Systemic Acute Toxicants in Drinking Water

    Directory of Open Access Journals (Sweden)

    Xinyan Zhao

    2013-12-01

    Full Text Available A bioluminescent-cell-based microfluidic device for sensing toxicants in drinking water was designed and fabricated. The system employed Vibrio fischeri cells as broad-spectrum sensors to monitor potential systemic cell toxicants in water, such as heavy metal ions and phenol. Specifically, the chip was designed for continuous detection. The chip design included two counter-flow micromixers, a T-junction droplet generator and six spiral microchannels. The cell suspension and water sample were introduced into the micromixers and dispersed into droplets in the air flow. This guaranteed sufficient oxygen supply for the cell sensors. Copper (Cu2+, zinc (Zn2+, potassium dichromate and 3,5-dichlorophenol were selected as typical toxicants to validate the sensing system. Preliminary tests verified that the system was an effective screening tool for acute toxicants although it could not recognize or quantify specific toxicants. A distinct non-linear relationship was observed between the zinc ion concentration and the Relative Luminescence Units (RLU obtained during testing. Thus, the concentration of simple toxic chemicals in water can be roughly estimated by this system. The proposed device shows great promise for an early warning system for water safety.

  1. The influence of network structure upon sediment routing in two disturbed catchments, East Cape, New Zealand

    Science.gov (United States)

    Walley, Yasmin; Tunnicliffe, Jon; Brierley, Gary

    2018-04-01

    Lateral inputs from hillslopes and tributaries exert a variable impact upon the longitudinal connectivity of sediment transfer in river systems with differing drainage network configurations. Network topology influences channel slope and confinement at confluence zones, thereby affecting patterns of sediment storage and the conveyance of sediments through catchments. Rates of disturbance response, patterns of sediment propagation, and the implications for connectivity and recovery were assessed in two neighbouring catchments with differing network configurations on the East Cape of New Zealand. Both catchments were subject to forest clearing in the late 1940s and a major cyclonic storm in 1988. However, reconstruction of landslide runout pathways, and characterization of connectivity using a Tokunaga framework, demonstrates different patterns and rates of sediment transfer and storage in a dendritic network relative to a more elongate, herringbone drainage network. The dendritic network has a higher rate of sediment transfer between storage sites in successive Strahler orders, whereas longitudinal connectivity along the fourth-order mainstem is disrupted by lateral sediment inputs from multiple low-order tributaries in the more elongate, herringbone network. In both cases the most dynamic ('hotspot') reaches are associated with a high degree of network side-branching.

  2. Impact of Molecular Orientation and Packing Density on Electronic Polarization in the Bulk and at Surfaces of Organic Semiconductors

    KAUST Repository

    Ryno, Sean

    2016-05-16

    The polarizable environment surrounding charge carriers in organic semiconductors impacts the efficiency of the charge transport process. Here, we consider two representative organic semiconductors, tetracene and rubrene, and evaluate their polarization energies in the bulk and at the organic-vacuum interface using a polarizable force field that accounts for induced-dipole and quadrupole interactions. Though both oligoacenes pack in a herringbone motif, the tetraphenyl substituents on the tetracene backbone of rubrene alter greatly the nature of the packing. The resulting change in relative orientations of neighboring molecules is found to reduce the bulk polarization energy of holes in rubrene by some 0.3 eV when compared to tetracene. The consideration of model organic-vacuum interfaces highlights the significant variation in the electrostatic environment for a charge carrier at a surface although the net change in polarization energy is small; interestingly, the environment of a charge even just one layer removed from the surface can be viewed already as representative of the bulk. Overall, it is found that in these herringbone-type layered crystals the polarization energy has a much stronger dependence on the intralayer packing density than interlayer packing density.

  3. Fast preparation of PtRu catalysts supported on carbon nanofibers by the microwave-polyol method and their application to fuel cells.

    Science.gov (United States)

    Tsuji, Masaharu; Kubokawa, Masatoshi; Yano, Ryuto; Miyamae, Nobuhiro; Tsuji, Takeshi; Jun, Mun-Suk; Hong, Seonghwa; Lim, Seongyop; Yoon, Seong-Ho; Mochida, Isao

    2007-01-16

    PtRu alloy nanoparticles (24 +/- 1 wt %, Ru/Pt atomic ratios = 0.91-0.97) supported on carbon nanofibers (CNFs) were prepared within a few minutes by using a microwave-polyol method. Three types of CNFs with very different surface structures, such as platelet, herringbone, and tubular ones, were used as new carbon supports. The dependence of particles sizes and electrochemical properties on the structures of CNFs was examined. It was found that the methanol fuel cell activities of PtRu/CNF catalysts were in the order of platelet > tubular > herringbone. The methanol fuel cell activities of PtRu/CNFs measured at 60 degrees C were 1.7-3.0 times higher than that of a standard PtRu (29 wt %, Ru/Pt atomic ratio = 0.92) catalyst loaded on carbon black (Vulcan XC72R) support. The best electrocatalytic activity was obtained for the platelet CNF, which is characterized by its edge surface and high graphitization degree.

  4. Development of Deflection Prediction Model for Concrete Block Pavement Considering the Block Shapes and Construction Patterns

    Directory of Open Access Journals (Sweden)

    Wuguang Lin

    2016-01-01

    Full Text Available Concrete block pavement (CBP is distinct from typical concrete or asphalt pavements. It is built by using individual blocks with unique construction patterns forming a discrete surface layer to bear traffic loadings. The surface structure of CBP varies depending on the block shapes and construction patterns, so it is hard to apply a general equivalent elastic modulus estimation method to define the surface structural strength. In this study, FEM analysis and dynamic loading test were carried out to develop a deflection prediction model for CBP considering the block shapes and construction patterns. Based on the analysis results, it was found that block shapes did not have much effect on load distribution, whereas construction patterns did. By applying the deflection prediction model to the rutting model for CBP proposed by Sun, the herringbone bond pattern showed the best performance comparing with stretcher bond or basket weave bond pattern. As the load repetition increased to 1.2 million, the rutting depth of CBP constructed by herringbone bond pattern was 2 mm smaller than those constructed by the other two patterns.

  5. Molecular chains and carpets of sexithiophenes on Au(111)

    Science.gov (United States)

    Glowatzki, H.; Duhm, S.; Braun, K.-F.; Rabe, J. P.; Koch, N.

    2007-09-01

    The two organic molecular materials α -sexithiophene (6T) and α,ω -dihexylsexithiophene (DH6T) adsorbed on Au(111) in the (sub)monolayer range were investigated by scanning tunneling microscopy (STM) in order to explore the effect of alkyl substitution on the self-assembly at surfaces. Metal substrate step edges are identified as preferred nucleation sites for 6T, while stable nucleus formation for DH6T occurs at kinks of the Au(111) herringbone reconstruction. At low coverage, 6T forms continuous chains of single-molecular width along Au step edges, involving molecular conformation changes by rotations around C-C bonds of neighboring thiophene units. In contrast, DH6T exhibits no ordered structures in the submonolayer range. At monolayer coverage, substantially different structures were observed for the two molecules. 6T forms rows of molecules with parallel long molecular axes, whereas DH6T forms lines along these axes, where the conjugated cores are embedded in a matrix of hexyl chains. Because of different preferred nucleation sites, 6T forms a continuous molecular carpet on extended Au(111) terraces, whereas DH6T resembles a patchworklike carpet as domain boundaries are induced by the Au(111) herringbone surface structure, leading to reduced domain sizes. Alkylation of 6T thus drastically changes the adsorption behavior and the resulting layer structure on the Au surface. These results should be valuable for developing new directed self-assembly schemes on prepatterned surfaces.

  6. Polymorph-Dependent Green, Yellow, and Red Emissions of Organic Crystals for Laser Applications.

    Science.gov (United States)

    Xu, Zhenzhen; Zhang, Zhiwei; Jin, Xue; Liao, Qing; Fu, Hongbing

    2017-12-05

    Color tuning of organic solid-state luminescent materials remains difficult and time-consuming through conventional chemical synthesis. Herein, we reported highly efficient polymorph-dependent green (P1), yellow (P2), and red (P3) emissions of organic crystals made by the same molecular building blocks of 4-(2-{4-[2-(4-diphenylamino-phenyl)-vinyl]-phenyl}-vinyl)-benzonitrile (DOPVB). Single-crystal X-ray diffraction (XRD) and spectroscopic data reveal that all three polymorphs follow the herringbone packing motif in H-type aggregations. On the one hand, from P1, P2 to P3, the reduced pitch translation along π stacks increases the intermolecular interactions between adjacent molecules, therefore leading to gradually red-shifted emissions from 540, 570 to 614 nm. On the other hand, the edge-to-face arrangement and large roll translations avoid strong π-π overlap, making P1, P2 and P3 highly emissive with record-high solid-state fluorescence quantum yields of 0.60, 0.98, and 0.68, respectively. Furthermore, the optically allowed 0-1 transitions of herringbone H-aggregates of P1, P2 and P3 naturally provide a four-level scheme, enabling green and yellow amplified spontaneous emissions (ASE) with very low thresholds. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Optimizing the CSP Tower Air Brayton Cycle System to Meet the SunShot Objectives - Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Bryner, Elliott [Soutwest Research Inst., San Antonio, TX (United States); Brun, Klaus [Soutwest Research Inst., San Antonio, TX (United States); Coogan, Shane [Soutwest Research Inst., San Antonio, TX (United States); Cunningham, C. Seth [Soutwest Research Inst., San Antonio, TX (United States); Poerner, Nathan [Soutwest Research Inst., San Antonio, TX (United States)

    2016-02-26

    The objective of this project is to increase Concentrated Solar Power (CSP) tower air receiver and gas turbine temperature capabilities to 1,000ºC by the development of a novel gas turbine combustor, which can be integrated on a megawatt-scale gas turbine, such as the Solar Turbines Mercury 50™. No combustor technology currently available is compatible with the CSP application target inlet air temperature of 1,000°C. Autoignition and flashback at this temperature prevent the use of conventional lean pre-mix injectors that are currently employed to manage NOx emissions. Additional challenges are introduced by the variability of the high-temperature heat source provided by the field of solar collectors, the heliostat in CSP plants. For optimum energy generation from the power turbine, the turbine rotor inlet temperature (TRIT) should remain constant. As a result of changing heat load provided to the solar collector from the heliostat, the amount of energy input required from the combustion system must be adjusted to compensate. A novel multi-bank lean micro-mix injector has been designed and built to address the challenges of high-temperature combustion found in CSP applications. The multi-bank arrangement of the micro-mix injector selectively injects fuel to meet the heat addition requirements to maintain constant TRIT with changing solar load. To validate the design, operation, and performance of the multi-bank lean micro-mix injector, a novel combustion test facility has been designed and built at Southwest Research Institute® (SwRI®) in San Antonio, TX. This facility, located in the Turbomachinery Research Facility, provides in excess of two kilograms per second of compressed air at nearly eight bar pressure. A two-megawatt electric heater raises the inlet temperature to 800°C while a secondary gas-fired heater extends the operational temperature range of the facility to 1,000°C. A combustor test rig connected to the heater has been designed and built to

  8. Evaluation of cooling performance of impinging jet array over various dimpled surfaces

    Science.gov (United States)

    Kim, Sun-Min; Kim, Kwang-Yong

    2016-04-01

    Various configurations of an impinging jet-dimple array cooling system were evaluated in terms of their heat transfer and pressure drop performances. The steady incompressible laminar flow and heat transfer in the cooling system were analyzed using three-dimensional Navier-Stokes equations. The obtained numerical results were validated by a comparison with experimental data for the local Nusselt number distribution. The area-averaged Nusselt number on the projected area and the pressure drop through the system were selected as the performance parameters. Among the four tested configurations—inline concave, staggered concave, inline convex, and staggered convex—the staggered convex impinging jet-dimple array showed the best heat transfer performance whereas the staggered-concave configuration showed the lowest pressure drop. A parametric study with two geometric variables, i.e., the height of dimple and the diameter of dimple, was also conducted for the staggered-convex impinging jet-dimple array. As a result, the best heat transfer and pressure drop performances were achieved when the ratio of the height of dimple to the diameter of jet was 0.8. And, the increase in the ratio of the diameter of dimple to the diameter of jet yielded monotonous increase in the heat transfer performance.

  9. Increasing cDNA yields from single-cell quantities of mRNA in standard laboratory reverse transcriptase reactions using acoustic microstreaming.

    Science.gov (United States)

    Boon, Wah Chin; Petkovic-Duran, Karolina; Zhu, Yonggang; Manasseh, Richard; Horne, Malcolm K; Aumann, Tim D

    2011-07-11

    Correlating gene expression with cell behavior is ideally done at the single-cell level. However, this is not easily achieved because the small amount of labile mRNA present in a single cell (1-5% of 1-50 pg total RNA, or 0.01-2.5 pg mRNA, per cell) mostly degrades before it can be reverse transcribed into a stable cDNA copy. For example, using standard laboratory reagents and hardware, only a small number of genes can be qualitatively assessed per cell. One way to increase the efficiency of standard laboratory reverse transcriptase (RT) reactions (i.e. standard reagents in microliter volumes) comprising single-cell amounts of mRNA would be to more rapidly mix the reagents so the mRNA can be converted to cDNA before it degrades. However this is not trivial because at microliter scales liquid flow is laminar, i.e. currently available methods of mixing (i.e. shaking, vortexing and trituration) fail to produce sufficient chaotic motion to effectively mix reagents. To solve this problem, micro-scale mixing techniques have to be used. A number of microfluidic-based mixing technologies have been developed which successfully increase RT reaction yields. However, microfluidics technologies require specialized hardware that is relatively expensive and not yet widely available. A cheaper, more convenient solution is desirable. The main objective of this study is to demonstrate how application of a novel "micromixing" technique to standard laboratory RT reactions comprising single-cell quantities of mRNA significantly increases their cDNA yields. We find cDNA yields increase by approximately 10-100-fold, which enables: greater numbers of genes to be analyzed per cell; more quantitative analysis of gene expression; and better detection of low-abundance genes in single cells. The micromixing is based on acoustic microstreaming, a phenomenon where sound waves propagating around a small obstacle create a mean flow near the obstacle. We have developed an acoustic microstreaming

  10. Degenerate and chiral states in the extended Heisenberg model on the kagome lattice

    Science.gov (United States)

    Gómez Albarracín, F. A.; Pujol, P.

    2018-03-01

    We present a study of the low-temperature phases of the antiferromagnetic extended classical Heisenberg model on the kagome lattice, up to third-nearest neighbors. First, we focus on the degenerate lines in the boundaries of the well-known staggered chiral phases. These boundaries have either semiextensive or extensive degeneracy, and we discuss the partial selection of states by thermal fluctuations. Then, we study the model under an external magnetic field on these lines and in the staggered chiral phases. We pay particular attention to the highly frustrated point, where the three exchange couplings are equal. We show that this point can be mapped to a model with spin-liquid behavior and nonzero chirality. Finally, we explore the effect of Dzyaloshinskii-Moriya (DM) interactions in two ways: a homogeneous and a staggered DM interaction. In both cases, there is a rich low-temperature phase diagram, with different spontaneously broken symmetries and nontrivial chiral phases.

  11. Leakage current suppression with a combination of planarized gate and overlap/off-set structure in metal-induced laterally crystallized polycrystalline-silicon thin-film transistors

    Science.gov (United States)

    Chae, Hee Jae; Seok, Ki Hwan; Lee, Sol Kyu; Joo, Seung Ki

    2018-04-01

    A novel inverted staggered metal-induced laterally crystallized (MILC) polycrystalline-silicon (poly-Si) thin-film transistors (TFTs) with a combination of a planarized gate and an overlap/off-set at the source-gate/drain-gate structure were fabricated and characterized. While the MILC process is advantageous for fabricating inverted staggered poly-Si TFTs, MILC TFTs reveal higher leakage current than TFTs crystallized by other processes due to their high trap density of Ni contamination. Due to this drawback, the planarized gate and overlap/off-set structure were applied to inverted staggered MILC TFTs. The proposed device shows drastic suppression of leakage current and pinning phenomenon by reducing the lateral electric field and the space-charge limited current from the gate to the drain.

  12. Phase Transitions in Even-Even Palladium Isotopes

    Directory of Open Access Journals (Sweden)

    Diab S. M.

    2009-01-01

    Full Text Available The positive and negative parity states of the even-even palladium isotopes were stud- ied within the frame work of the interacting boson approximation model (IBA-1. The energy spectra, potential energy surfaces, electromagnetic transition probabilities, back bending and staggering effect have been calculated. The potential energy surfaces show smooth transition from vibrational-like to gamma-soft and finally to rotational-like nu- clei. Staggering effectle, has been observed between the positive and negative parity states in palladium isotopes. The agreement between theoretical predictions and exper- imental values are fairly good.

  13. Phase Transitions in Even-Even Palladium Isotopes

    Directory of Open Access Journals (Sweden)

    Diab S. M.

    2009-01-01

    Full Text Available The positive and negative parity states of the even-even palladium isotopes were studied within the frame work of the interacting boson approximation model (IBA-1. The energy spectra, potential energy surfaces, electromagnetic transition probabilities, back bending and staggering effect have been calculated. The potential energy surfaces show smooth transition from vibrational-like to gamma-soft and finally to rotational-like nuclei. Staggering effectle, has been observed between the positive and negative parity states in palladium isotopes. The agreement between theoretical predictions and experimental values are fairly good.

  14. 3D Multi-Microchannel Helical Mixer Fabricated by Femtosecond Laser inside Fused Silica

    Directory of Open Access Journals (Sweden)

    Chao Shan

    2018-01-01

    Full Text Available Three-dimensional (3D multi-microchannel mixers can meet the requirements of different combinations according to actual needs. Rapid and simple creation of 3D multi-microchannel mixers in a “lab-on-a-chip” platform is a significant challenge in micromachining. In order to realize the complex mixing functions of microfluidic chips, we fabricated two kinds of complex structure micromixers for multiple substance mixes simultaneously, separately, and in proper order. The 3D multi-microchannel mixers are fabricated by femtosecond laser wet etch technology inside fused silica. The 3D multi-microchannel helical mixers have desirable uniformity and consistency, which will greatly expand their utility and scope of application.

  15. Design and fabrication of microfluidic mixer from carbonyl iron–PDMS composite membrane

    KAUST Repository

    Li, Jiaxing

    2010-10-12

    This paper introduces a carbonyl iron-PDMS (CI-PDMS) composite magnetic elastomer in which carbonyl iron (CI) particles are uniformly distributed in a PDMS matrix. The CI particles and the PDMS were mixed at different weight ratios and tested to determine the influence of CI concentration. The magnetic and mechanical properties of the magnetic elastomers were characterized, respectively, by vibrating-sample magnetometer and by tensile testing using a mechanical analyzer. The elastomer was found to exhibit high magnetization and good mechanical flexibility. The morphology and deformation of the CI-PDMS membrane also were observed. A magnetically actuated microfluidic mixer (that is, a micromixer) integrated with CI-PDMS elastomer membranes was successfully designed and fabricated. The high efficiency and quality of the mixing makes possible the impressive potential applications of this unique CI-PDMS material in microfluidic systems. © Springer-Verlag 2010.

  16. The Effects of Mixing, Reaction Rates, and Stoichiometry on Yield for Mixing Sensitive Reactions—Part I: Model Development

    Directory of Open Access Journals (Sweden)

    Syed Imran A. Shah

    2012-01-01

    Full Text Available There are two classes of mixing sensitive reactions: competitive-consecutive and competitive-parallel. The yield of desired product from these coupled reactions depends on how fast the reactants are brought together. Recent experimental results have suggested that the mixing effect may depend strongly on the stoichiometry of the reactions. To investigate this, a 1D, dimensionless, reaction-diffusion model at the micromixing scale was developed. Assuming constant mass concentration and mass diffusivities, systems of PDE's were derived on a mass fraction basis for both types of reactions. Two dimensionless reaction rate ratios and a single general Damköhler number emerged from the analysis. The resulting dimensionless equations were used to investigate the effects of mixing, reaction rate ratio, and reaction stoichiometry. As expected, decreasing either the striation thickness or the dimensionless rate ratio maximizes yield, the reaction stoichiometry has a considerable effect on yield, and all three variables interact strongly.

  17. Fine structuration of low-temperature co-fired ceramic (LTCC) microreactors.

    Science.gov (United States)

    Jiang, Bo; Haber, Julien; Renken, Albert; Muralt, Paul; Kiwi-Minsker, Lioubov; Maeder, Thomas

    2015-01-21

    The development of microreactors that operate under harsh conditions is always of great interest for many applications. Here we present a microfabrication process based on low-temperature co-fired ceramic (LTCC) technology for producing microreactors which are able to perform chemical processes at elevated temperature (>400 °C) and against concentrated harsh chemicals such as sodium hydroxide, sulfuric acid and hydrochloric acid. Various micro-scale cavities and/or fluidic channels were successfully fabricated in these microreactors using a set of combined and optimized LTCC manufacturing processes. Among them, it has been found that laser micromachining and multi-step low-pressure lamination are particularly critical to the fabrication and quality of these microreactors. Demonstration of LTCC microreactors with various embedded fluidic structures is illustrated with a number of examples, including micro-mixers for studies of exothermic reactions, multiple-injection microreactors for ionone production, and high-temperature microreactors for portable hydrogen generation.

  18. Soft lithography of ceramic microparts using wettability-tunable poly(dimethylsiloxane) (PDMS) molds

    International Nuclear Information System (INIS)

    Su, Bo; Zhang, Aijun; Meng, Junhu; Zhang, Zhaozhu

    2016-01-01

    Green alumina microparts were fabricated from a high solid content aqueous suspension by microtransfer molding using air plasma-treated poly(dimethylsiloxane) (PDMS) molds. The wettability of the air plasma-treated PDMS molds spontaneously changed between the hydrophilic and hydrophobic states during the process. Initial hydrophilicity of the air plasma-treated PDMS molds significantly improved the flowability of the concentrated suspension. Subsequent hydrophobic recovery of the air plasma-treated PDMS molds enabled a perfect demolding of the green microparts. Consequently, defect-free microchannel parts of 60 μ m and a micromixer with an area of several square centimeters were successfully fabricated. In soft lithography, tuning the wetting behavior of PDMS molds has a great effect on the quality of ceramic microparts. Using wettability-tunable PDMS molds has great potential in producing complex-shaped and large-area ceramic microparts and micropatterns. (paper)

  19. Operating experience of a portable thermophotovoltaic power supply

    Science.gov (United States)

    Becker, Frederick E.; Doyle, Edward F.; Shukla, Kailash

    1999-03-01

    Two configurations of man-portable thermophotovoltaic (TPV) power supplies based on Thermo Power's supported continuous fiber emitter have been designed, built, and are being tested. The systems use narrow-band, fibrous, ytterbia emitters radiating to bandgap matched silicon photovoltaic arrays with dielectric stack filters for optical energy recovery and recuperators for thermal energy recovery. The systems have been designed for operation with propane and with combustion air preheat temperatures of up to 1250 K. To operate at air preheat temperatures above the auto-ignition temperature of the fuel, a unique fuel delivery system was devised which results in the micromixing and rapid combustion of the fuel and air right in the emitter fibers. This allows the ytterbia emitter fibers to run much hotter (˜2000 K) than any of the surrounding structure.

  20. Photothermal generation of microbubbles on plasmonic nanostructures inside microfluidic channels

    Science.gov (United States)

    Li, Jingting; Li, Ming; Santos, Greggy M.; Zhao, Fusheng; Shih, Wei-Chuan

    2016-03-01

    Microbubbles have been utilized as micro-pumps, micro-mixers, micro-valves, micro-robots and surface cleaners. Various generation techniques can be found in the literature, including resistive heating, hydrodynamic methods, illuminating patterned metal films and noble metal nanoparticles of Au or Ag. We present photothermal microbubble generation by irradiating nanoporous gold disk covered microfluidic channels. The size of the microbubble can be controlled by adjusting the laser power. The dynamics of both bubble growth and shrinkage are studied. The advantages of this technique are flexible bubble generation locations, long bubble lifetimes, no need for light-adsorbing dyes, high controllability over bubble size, low power consumption, etc. This technique has the potential to provide new flow control functions in microfluidic devices.

  1. CONTINUOUS AND SEMICONTINUOUS REACTION SYSTEMS FOR HIGH-SOLIDS ENZYMATIC HYDROLYSIS OF LIGNOCELLULOSICS

    Directory of Open Access Journals (Sweden)

    A. González Quiroga

    2015-12-01

    Full Text Available Abstract An attractive operation strategy for the enzymatic hydrolysis of lignocellulosics results from dividing the process into three stages with complementary goals: continuous enzyme adsorption at low-solids loading (5% w/w with recycling of the liquid phase; continuous liquefaction at high-solids content (up to 20% w/w; and, finally, continuous or semicontinuous hydrolysis with supplementation of fresh enzymes. This paper presents a detailed modeling and simulation framework for the aforementioned operation strategies. The limiting micromixing situations of macrofluid and microfluid are used to predict conversions. The adsorption and liquefaction stages are modeled as a continuous stirred tank and a plug flow reactor, respectively. Two alternatives for the third stage are studied: a train of five cascading stirred tanks and a battery of batch reactors in parallel. Simulation results show that glucose concentrations greater than 100 g L-1 could be reached with both of the alternatives for the third stage.

  2. Surfactant-free fabrication of fullerene C{sub 60} nanotubules under shear

    Energy Technology Data Exchange (ETDEWEB)

    Vimalanathan, Kasturi; Raston, Colin L. [Flinders Centre for NanoScale Science Technology (CNST) Chemical and Physical Sciences, Flinders University, Adelaide (Australia); Shrestha, Rekha Goswami [International Centre for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki (Japan); Zhang, Zhi; Zou, Jin [Materials Engineering and Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, QLD (Australia); Nakayama, Tomonobu [International Centre for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki (Japan); Graduate School of Pure and Applied Sciences, University of Tsukuba, Ibaraki (Japan)

    2017-07-10

    A method for controlling the self-assembly of fullerene C{sub 60} molecules into nanotubules in the fcc phase, devoid of entrapped solvent, has been established in a thin film microfluidic device. The micron length C{sub 60} nanotubules, with individual hollow diameters of 100 to 400 nm, are formed under continuous flow processing during high shear micromixing of water and a toluene solution of the fullerene, in the absence of surfactant, and without the need for further down-stream processing. TEM revealed pores on the surface of the nanotubes, and the isolated material has a much higher response to small molecule sensing than that for analogous material formed using multistep batch processing. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Bis(1,3-dimethyl-1H-imidazolium hexafluorosilicate: the second monoclinic polymorph

    Directory of Open Access Journals (Sweden)

    Maxim V. Borzov

    2013-08-01

    Full Text Available The title compound, 2C5H9N2+·SiF62−, (I, crystallized as a new polymorph, different from the previously reported one (Ia [Light et al. (2007 private communication (refcode: NIQFAV. CCDC, Cambridge, England]. The symmetry [space groups P21/n for (I and C2/c for(Ia] and crystal packing patterns are markedly different for this pair of polymorphs. In (I, all imidazolium cations in the lattice are nearly parallel to each other, whereas a herringbone arrangement can be found in (Ia. In (I, each SiF62– dianion forms four short C—H...F contacts with adjacent C5H9N2+ cations, resulting in the formation of layers parallel to the ac plane. In (Ia, the C—H...F contacts are generally longer and result in the formation of layers along the bc plane.

  4. Spin magnetic moments from single atoms to small Cr clusters

    Energy Technology Data Exchange (ETDEWEB)

    Boeglin, C.; Decker, R.; Bulou, H.; Scheurer, F.; Chado, I. [IPCMS-GSI - UMR 7504, 67037 Strasbourg Cedex (France); Ohresser, P. [LURE, 91405 Orsay (France); Dhesi, S.S. [ESRF, BP 220, 38043 Grenoble Cedex (France); Present permanent address: Diamond Light Source, Chilton, Didcot OX11 0QX (United Kingdom); Gaudry, E. [LMCP, 4, place Jussieu, 75252 Paris (France); Lazarovits, B. [CCMS, T.U. Vienna, Gumpendorfstr. 1a, 1060 Wien (Austria)

    2005-07-01

    Morphology studies at the first stages of the growth of Cr/Au(111) are reported and compared to the magnetic properties of the nanostructures. We analyze by Scanning Tunneling Microscopy and Low Energy Electron Diffraction the Cr clusters growth between 200 K and 300 K. In the early stages of the growth the morphology of the clusters shows monoatomic high islands located at the kinks of the herringbone reconstructed Au(111) surface. By X-ray Magnetic Circular Dichroism performed on the Cr L{sub 2,3} edges it is shown that the temperature dependent morphology strongly influences the magnetic properties of the Cr clusters. We show that in the sub-monolayer regime Cr clusters are antiferromagnetic and paramagnetic when the size reaches the atomic limit. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Synthesis and Antibacterial Activity of Antibiotic-Functionalized Graphite Nanofibers

    Directory of Open Access Journals (Sweden)

    Madeline Rotella

    2015-01-01

    Full Text Available Surface functionalization of nanomaterials is an area of current investigation that supports the development of new biomaterials for applications in biology and medicine. Herein we describe the synthesis, characterization, and antibacterial properties of the first examples of antibiotic-labeled graphitic carbon nanofibers (GCNFs covalently functionalized with aminoglycoside and quinolone antibiotics. Ruthenium tetroxide oxidation of herringbone GCNFs gave higher amounts of surface carboxyl groups than previous methods. These carboxyl groups served as sites of attachment for antibiotics by acyl substitution. Bioassay of these novel, functionalized GCNFs using serial dilution and optical density methods demonstrated that antibiotic-labeled GCNFs possess significant antibacterial activity against Pseudomonas aeruginosa. The activity we observe for aminoglycoside-functionalized GCNFs suggests a membranolytic mechanism of action.

  6. Rectified transport of a ring containing self-propelled particles

    Science.gov (United States)

    Huang, Xiao-Qun; Liao, Jing-Jing; Ai, Bao-Quan

    2018-02-01

    Rectified transport of a ring containing self-propelled particles is numerically investigated in a two-dimensional herringbone potential. It is found that the ring powered by active particles can be rectified in the asymmetric potential and the direction of the transport is determined by the asymmetry of the potential. The ring radius can strongly affect the transport and the role of the radius on the average velocity depends on the profile of the potential and the self-propulsion speed. There exist optimal values of the parameters (the self-propulsion and the modulation parameter of the potential) at which the average velocity takes its maximal value. The average velocity decreases monotonously with increase of the parameters (the translational diffusion, the rotational diffusion and the particle number).

  7. Durability test with fuel starvation using a Pt/CNF catalyst in PEMFC.

    Science.gov (United States)

    Jung, Juhae; Park, Byungil; Kim, Junbom

    2012-01-05

    In this study, a catalyst was synthesized on carbon nanofibers [CNFs] with a herringbone-type morphology. The Pt/CNF catalyst exhibited low hydrophilicity, low surface area, high dispersion, and high graphitic behavior on physical analysis. Electrodes (5 cm2) were prepared by a spray method, and the durability of the Pt/CNF was evaluated by fuel starvation. The performance was compared with a commercial catalyst before and after accelerated tests. The fuel starvation caused carbon corrosion with a reverse voltage drop. The polarization curve, EIS, and cyclic voltammetry were analyzed in order to characterize the electrochemical properties of the Pt/CNF. The performance of a membrane electrode assembly fabricated from the Pt/CNF was maintained, and the electrochemical surface area and cell resistance showed the same trend. Therefore, CNFs are expected to be a good support in polymer electrolyte membrane fuel cells.

  8. Physicochemical investigations of carbon nanofiber supported Cu/ZrO{sub 2} catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Din, Israf Ud, E-mail: drisraf@yahoo.com, E-mail: maizats@petronas.com.my; Shaharun, Maizatul S., E-mail: drisraf@yahoo.com, E-mail: maizats@petronas.com.my [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS (Malaysia); Subbarao, Duvvuri, E-mail: duvvuri-subbarao@petronas.com.my [Department of Chemical Engineering, Universiti Teknologi PETRONAS (Malaysia); Naeem, A., E-mail: naeeem64@yahoo.com [National Centre of Excellence in Physical Chemistry, University of Peshawar (Pakistan)

    2014-10-24

    Zirconia-promoted copper/carbon nanofiber catalysts (Cu‐ZrO{sub 2}/CNF) were prepared by the sequential deposition precipitation method. The Herringbone type of carbon nanofiber GNF-100 (Graphite nanofiber) was used as a catalyst support. Carbon nanofiber was oxidized to (CNF-O) with 5% and 65 % concentration of nitric acid (HNO{sub 3}). The CNF activated with 5% HNO{sub 3} produced higher surface area which is 155 m{sup 2}/g. The catalyst was characterized by X-ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR) and N{sub 2} adsorption-desorption. The results showed that increase of HNO{sub 3} concentration reduced the surface area and porosity of the catalyst.

  9. Wave journal bearing with compressible lubricant--Part 1: The wave bearing concept and a comparison to the plain circular bearing

    Science.gov (United States)

    Dimofte, Florin

    1995-01-01

    To improve hydrodynamic journal bearing steady-state and dynamic performance, a new bearing concept, the wave journal bearing, was developed at the author's lab. This concept features a waved inner bearing diameter. Compared to other alternative bearing geometries used to improve bearing performance such as spiral or herring-bone grooves, steps, etc., the wave bearing's design is relatively simple and allows the shaft to rotate in either direction. A three-wave bearing operating with a compressible lubricant, i.e., gas is analyzed using a numerical code. Its performance is compared to a plain (truly) circular bearing over a broad range of bearing working parameters, e.g., bearing numbers from 0.01 to 100.

  10. Low-temperature redetermination of 1,3-bis(pentafluorophenyltriazene

    Directory of Open Access Journals (Sweden)

    Annemarie Kuhn

    2010-12-01

    Full Text Available The crystal structure of the title compound, (C6F52N3H, is stabilized by N—H...N hydrogen bonding, forming centrosymmetric dimers organized in a herringbone motif. Important geometrical parameters are N—N = 1.272 (2 and 1.330 (2 Å and N—N—N = 112.56 (15°. The dihedral angle between C6F5 groups is 21.22 (9°. The room temperature structure was reported by Leman et al. (1993. Inorg. Chem. 32, 4324–4336]. In the current determination, the data were collected to a higher θ angle, resulting in higher precision for the C—C bond lengths(0.001–0.005 versus 0.003 Å.

  11. Influence of additives on phase stabilization of scandia-doped zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Muccillo, Eliana Navarro dos Santos; Grosso, Robson Lopes; Reis, Shirley Leite dos; Muccillo, Reginaldo, E-mail: enavarro@usp.br, E-mail: roblopeg@usp.br, E-mail: shirley.reis@usp.br, E-mail: muccillo@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2017-04-15

    The effects of small additions of tin, zinc, calcium and boron oxides on phase composition and electrical conductivity of zirconia-10 mol% scandia were investigated. Compounds containing 1 mol% zinc, tin and calcium oxides and 1, 3 and 5 wt.% boron oxide were prepared by solid state reaction and characterized by X-ray diffraction, density measurements, scanning electron microscopy and impedance spectroscopy. Full stabilization of the cubic structure at room temperature was obtained with additions of 1 mol% calcium oxide and 2 wt.% boron oxide. Partially stabilized compounds exhibit herringbone structure, characteristic of the β- rhombohedric phase. Specimens with calcium as additive show total conductivity of 23.8 mS.cm{sup -1} at 750 deg C with activation energy of 1.13 eV. Liquid phase sintering by boron oxide addition is effective to enhance the densification of the solid electrolyte. (author)

  12. Der Einfluss elastischer Gummimatten im Melkstand auf die Klauenmaße von Milchkühen

    Directory of Open Access Journals (Sweden)

    Barbara Benz

    2014-12-01

    Full Text Available Hoof diseases and disorders are a big animal welfare problem in dairy herds and one of the most common cause of losses on German dairy cattle farms. Any deviation from the correct claw shape may lead to unphysiological loading and as a consequence of this to hoof diseases. The present study compares the claw shape of German Simmental Cows in a stable before and after the installation of elastic rubber mats in a steep herringbone parlour. In the beginning there existed an abrasive soil and the height of the bulb was too low in 87 % of cows. Four months after the installation of the mats, 77 % of the cows had bulb heights within the reference range. No differences between claw measurements were found depending on milk yield and number of lactation. The results of this study indicated that the flooring surface in a milking parlour had a significant influence on claw shape.

  13. Solvent-assisted growth of metal phthalocyanine thin films on Au(111)

    Energy Technology Data Exchange (ETDEWEB)

    Tskipuri, Levan; Shao Qian; Reutt-Robey, Janice [Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742-4454 (United States)

    2012-05-15

    Thin films of metal phthalocyanine (MPc) are grown on an Au(111) support with a newly developed aerosol molecular beam deposition source and characterized in situ via ultrahigh vacuum scanning tunneling microscopy. MPcs are delivered to Au(111) in a series of N{sub 2}-entrained microsized solvent droplets of variable surface residence time. Phthalocyanine film registration to the herringbone reconstruction of the Au(111) surface, indicative of thermodynamically favored structure, is observed at submonolayer coverages for aromatic solvents with long residence times. Aerosol-deposited monolayer film structures are noncrystalline with tilted MPc orientations and vacancy nanocavities. Upon annealing, MPc molecules adopt flat-lying orientations with respect to the substrate and vacancies are eliminated. Film morphologies indicate solvation-mediated film nucleation and growth, with less long-range ordering that in vapor-generated films.

  14. Coverage Dependent Assembly of Anthraquinone on Au(111)

    Science.gov (United States)

    Conrad, Brad; Deloach, Andrew; Einstein, Theodore; Dougherty, Daniel

    A study of adsorbate-adsorbate and surface state mediated interactions of anthraquinone (AnQ) on Au(111) is presented. We utilize scanning tunneling microscopy (STM) to characterize the coverage dependence of AnQ structure formation. Ordered structures are observed up to a single monolayer (ML) and are found to be strongly dependent on molecular surface density. While the complete ML forms a well-ordered close-packed layer, for a narrow range of sub-ML coverages irregular close-packed islands are observed to coexist with a disordered pore network linking neighboring islands. This network displays a characteristic pore size and at lower coverages, the soliton walls of the herringbone reconstruction are shown to promote formation of distinct pore nanostructures. We will discuss these nanostructure formations in the context of surface mediated and more direct adsorbate interactions.

  15. Influence of Chosen Stimulants on Selected Quality Ingredients of Cow's Milk and Rumen Parameters

    Directory of Open Access Journals (Sweden)

    Bohuslav Čermák

    2011-05-01

    Full Text Available The aim of this study was to determine the effect of liquid Biopolym FZT quality components in cow milk. During the reporting period was Biopolym, administered to dairy cows of Czech Pied breed in the selected milking robots equipped and furnished keeping herringbone parlor near Czech Budejovice. It found a slight increase in the average daily milk yield. The mean daily milk yield on the robot, which is dosed at Biopolym were 25.5 lt. On the other robot, which served as a control, the mean value of daily milk yield 23.5 lt. Because the components of milk a slight increase in fat levels in milk, while the impairment of protein. The barn equipped parlor, on the contrary to reduce fat content and increase protein content. Analyses were conducted rumen contents of fistuled dairy cows after dosage of Biopolym.

  16. Moiré pattern induced by the electronic coupling between 1-octanol self-assembled monolayers and graphite surface

    International Nuclear Information System (INIS)

    Silly, Fabien

    2012-01-01

    Two-dimensional self-assembly of 1-octanol molecules on a graphite surface is investigated using scanning tunneling microscopy (STM) at the solid/liquid interface. STM images reveal that this molecule self-assembles into a compact hydrogen-bonded herringbone nanoarchitecture. Molecules are preferentially arranged in a head-to-head and tail-to-tail fashion. A Moiré pattern appears in the STM images when the 1-octanol layer is covering the graphite surface. The large Moiré stripes are perpendicular to the 1-octanol lamellae. Interpretation of the STM images suggests that the Moiré periodicity is governed by the electronic properties of the graphite surface and the 1-octanol layer periodicity. (paper)

  17. Crystal structure of N-(tert-butoxycarbonylphenylalanyldehydroalanine isopropyl ester (Boc–Phe–ΔAla–OiPr

    Directory of Open Access Journals (Sweden)

    Paweł Lenartowicz

    2014-12-01

    Full Text Available In the title compound, the dehydrodipeptide (Boc–Phe–ΔAla–OiPr, C20H28N2O5, the molecule has a trans conformation of the N-methylamide group. The geometry of the dehydroalanine moiety is to some extent different from those usually found in simple peptides, indicating conjugation between the H2C=C group and the peptide bond. The bond angles around dehydroalanine have unusually high values due to the steric hindrance, the same interaction influencing the slight distortion from planarity of the dehydroalanine. The molecule is stabilized by intramolecular interactions between the isopropyl group and the N atoms of the peptide main chain. In the crystal, an N—H...O hydrogen bond links the molecules into ribbons, giving a herringbone head-to-head packing arrangement extending along the [100] direction. In the stacks, the molecules are linked by weak C—H...O hydrogen-bonding associations.

  18. Non-Contacting Finger Seals Static Performance Test Results at Ambient and High Temperatures

    Science.gov (United States)

    Proctor, Margaret P.

    2016-01-01

    The non-contacting finger seal is an advanced seal concept with potential to reduce specific fuel consumption in gas turbine engines by 2 to 3 with little to no wear of the seal or rotor. Static performance tests and bind-up tests of eight different non-contacting finger seal configurations were conducted in air at pressure differentials up to 689.4 kPa and temperatures up to 922 K. Four of the seals tested were designed to have lift pads concentric to a herringbone-grooved rotor which generates hydrodynamic lift when rotating. The remaining seals were tested with a smooth rotor; one seal had a circumferential taper and one had an axial taper on the lift pad inner diameter to create hydrodynamic lift during rotation. The effects of the aft finger axial thickness and of the forward finger inner diameter on leakage performance were investigated as well and compared to analytical predictions.

  19. Aerodynamic and thermal studies of cans of gas cooled fuel elements

    International Nuclear Information System (INIS)

    Gelin, P.

    1964-01-01

    Research on clusters was undertaken at the CEA in 1959, while studies on herring-bone cans were developed at the EDF Laboratory at Chatou and the CEA laboratory at Saclay at the end of 1959. In 1962, a general study on corrugations was begun at the Saclay Laboratory with a view to improving the clusters, and continued later in both laboratories relative to the internal cooling of annular fuel elements. As these studies progressed, trial facilities were extended while experimental methods have improved constantly. At the present time, both laboratories, working in complete collaboration, have powerful means at their disposal. Work on the clusters has been concerned chiefly with pressure losses due to the assembly parts, and with the temperature variations around the elements of the cluster. In this way, we have been able to determine satisfactorily the hot points of the can, the deformations of the rods and the conditions of stability of these deformations. In the case of the herring-bone cans, studies have been directed to the evolution of performances as a function of the geometric parameters on the one hand, and to the special aerodynamic and thermal features caused by the fins and by interruptions of cartridge on the other hand. These studies have led to a very thorough knowledge of the cartridges chosen for the reactors EDF 2 and EDF 3, and now open up very hopeful prospects for future reactors, particularly those fitted with annular elements; among the alternatives suitable for the inner surface of the annular element can, corrugations and longitudinal fins have been fairly extensively tested over a wide range of Reynolds number. (authors) [fr

  20. Teacher Perceptions and Experiences Using the Apple iPad as an Instructional Tool

    Science.gov (United States)

    Perez, Carlos Raul, Jr.

    2017-01-01

    The number of iPads in classrooms throughout the country is growing at a staggering rate. Educators and school districts are implementing iPad initiatives to enhance instruction. The purpose of this study was to examine high school teachers' experiences and perceptions after using the Apple iPad as an instructional tool in the classroom. An…

  1. Polyculture of penaeid shrimp in ponds receiving brackish heated effluent from a power plant

    Energy Technology Data Exchange (ETDEWEB)

    Ojeda, J.L.W.

    1983-01-01

    White shrimp Penaeus setiferus, were grown in monoculture or in polyculture with blue shrimp P. stylirostris, or striped mullet Mugil cephalus in 0.1-ha earthen ponds receiving heated effluent from the Houston Lighting and Power Company's Cedar Bayou Generating Station east of Baytown, Texas during 1978 and 1979. No detrimental effect of either species on white shrimp survival or yield was found. Blue shrimp was greater than that of white shrimp in the same ponds. Total yield was increased by polyculture. An experiment was performed in which blue shrimp were stocked conventionally into ponds, or stocked in three successive increments (staggered stocking study). A preliminary experiment was made in 1978, followed by a more expanded version in 1979. Staggered stocking increased pond yields compared to expected values from the control pond yields. There was no detrimental effect of staggered stocking on shrimp survival. Pond salinities were much lower in 1979 than in 1978, associated with lower shrimp growth, survival and yield. A distribution study performed in the staggered stocking study ponds revealed that blue shrimp in mixed-size culture tend to segregate by size, and that small shrimp show somewhat different distribution patterns and temporal activity patterns than large shrimp. All the organisms used also served as biological monitors of water quality. No detectable levels of pesticides were found in any of the cultured animals. The only heavy metal found in higher concentrations than in previous years at this site was chromium.

  2. Trees of Life: Saving Tropical Forests and Their Biological Wealth.

    Science.gov (United States)

    Miller, Kenton; Tangley, Laura

    Staggering statistics and dramatic headlines about the destruction of rain forests, the world's richest ecosystems, are only a small part of the devastating story of global deforestation. This volume provides comprehensive coverage of this complex scientific and political catastrophe-in-the-making and examines the costs and the consequences, in…

  3. The Chiral limit in lattice QCD

    International Nuclear Information System (INIS)

    Morel, A.

    1985-11-01

    Using the results of a quenched SU(2) simulation with staggered fermions, we discuss the small quark mass behaviour of m π 2 and f π 2 . The importance of finite size effects and of non linearities in the zero mass extrapolation is emphasized. Evidence for scaling of m π 2 and of a suitably determined value of f π 2 is presented

  4. Optimization of superconducting tiling pattern for superconducting bearings

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R. (Hinsdale, IL)

    1996-01-01

    An apparatus and method for reducing magnetic field inhomogeneities which produce rotational loss mechanisms in high temperature superconducting magnetic bearings. Magnetic field inhomogeneities are reduced by dividing high temperature superconducting structures into smaller structures, and arranging the smaller structures into tiers which stagger the magnetic field maximum locations of the smaller structures.

  5. Understanding Great Salt Lake Bird Festival Visitors: Applying the Recreational Specialization Framework

    Science.gov (United States)

    Steven W. Burr; David Scott

    2004-01-01

    The growth of birdwatching over the last two decades has been staggering. According to the recent National Survey of Recreation and the Environment (NSRE) (2000-2002), one-third (33%) of American adults said they went birdwatching at least once during the previous 12 months. According to NSRE data, the number of people who regarded themselves as birdwatchers increased...

  6. Molecular conformation and liquid structure of 2-propanol through ...

    Indian Academy of Sciences (India)

    neutron diffraction data [12]. 3. Method of analysis. 3.1 General background. In the following paragraph we present the extraction of total neutron molecular structure .... carbon and oxygen contributions and important information about the hydrogen positions ... the hydroxyl group OD1 is at a staggered position, as expected.

  7. 77 FR 41081 - Sulfentrazone; Pesticide Tolerances

    Science.gov (United States)

    2012-07-12

    ..., and reliability as well as the relationship of the results of the studies to human risk. EPA has also..., an increased incidence of clinical signs (staggered gait, splayed hind limbs, and abdominal gripping... physical and reflex development are likely secondary effects reflective of the poor general state of the...

  8. Study of the influence of a sinusoidal protuberance on the transfers ...

    African Journals Online (AJOL)

    The governing elliptic equations are discretized in a two-dimensional domain using the finite-volume method with non-staggered variable arrangement and the PISO algorithm for the velocity-pressure coupling is employed. We analyze the influence of the amplitude of the protuberance and the heat flux applied to its base ...

  9. Reproductive Endocrinology: Pregnancy and fertility after bariatric surgery.

    Science.gov (United States)

    Ginsburg, Elizabeth S

    2009-05-01

    Increases in rates of bariatric surgery are staggering, and many obese individuals who undergo such procedures are women of reproductive age. So, how does the surgery affect women's fertility and pregnancy outcomes thereafter? A new systemic review aimed to find out.

  10. Modern developments for ground-based monitoring of fire behavior and effects

    Science.gov (United States)

    Colin C. Hardy; Robert Kremens; Matthew B. Dickinson

    2010-01-01

    Advances in electronic technology over the last several decades have been staggering. The cost of electronics continues to decrease while system performance increases seemingly without limit. We have applied modern techniques in sensors, electronics and instrumentation to create a suite of ground based diagnostics that can be used in laboratory (~ 1 m2), field scale...

  11. Study of neutron-rich Mo isotopes by the projected shell model ...

    Indian Academy of Sciences (India)

    of yrast positive- and negative-parity bands are analysed and found to be in reasonable agreement with the experiments .... and negative-parity energy levels are compared with experiments and the staggering plots ...... [5] J Dobaczewski, in: Contemporary topics in nuclear structure physics edited by R F Casten,. A Frank ...

  12. Where is the value premium?

    NARCIS (Netherlands)

    Phalippou, L.

    2008-01-01

    The value premium is driven by 7 percent of the stock market. The 93 percent of market capitalization held most by institutional investors is value premium free. In contrast, in stocks held most by individual investors, the value premium, even when the stocks are value weighted, reaches a staggering

  13. Effects of turbine spacing on the power output of extended wind-farms

    NARCIS (Netherlands)

    Stevens, Richard Johannes Antonius Maria; Gayme, Dennice F.; Meneveau, Charles

    2016-01-01

    We present results from large eddy simulations of extended wind-farms for several turbine configurations with a range of different spanwise and streamwise spacing combinations. The results show that for wind-farms arranged in a staggered configuration with spanwise spacings in the range ≈[3.5,8]D,

  14. Teachers' perceptions of the Integrated Quality Management System ...

    African Journals Online (AJOL)

    Furthermore, the model should be well-resourced and be anchored on partnerships; concurrency of thrust; staggered changes and based on the following principles adapted from development discourse: participation, empowerment, ownership, learning, adaptability, and simplicity. There is consensus among stakeholders ...

  15. Effect of hybridization and dispersion of quasiparticles on the ...

    Indian Academy of Sciences (India)

    RNi2B2C (R = Tm, Er, Ho, Dy) show the coexistence of superconductivity and mag- netism [1–3] with high magnetic ordering temperatures. It is indeed .... However, we introduce a staggered magnetic field of strength h which simulates strong. AFM correlation of nickel electrons which is represented in the 2nd term of eq. (1).

  16. Exploring How to Change Stereotypical Attitudes toward Students Who Are LGBT

    Science.gov (United States)

    Roeck, Kathryn

    2008-01-01

    The experience of being a gay teen is tremendously difficult. The statistics regarding hate crimes and threats are staggering. The results of these threats are even more appalling: Gay and lesbian youth are at greater risk of dropping out of school, engaging in substance abuse, and running away from home, and are two to three times more likely to…

  17. Preparing Global Citizens through the Study of Human Rights

    Science.gov (United States)

    Kirkwood-Tucker, Toni Fuss

    2012-01-01

    The preparation of students for global citizenship represents a central challenge to social studies educators in the twenty-first century. Two-thirds of the world's poor are steeped in abject poverty and its grim consequences. The world refugee problem has reached staggering proportions. There is an international epidemic of human trafficking, and…

  18. CAS -- A Turboprop Solution for the COIN Fight

    Science.gov (United States)

    2009-04-14

    required or even produced by Empresa Brasileira de Aeronautica (Embraer) headquartered in Brazil. attractive... ,,7 Brazil Embraer EMB 314 Super...applications and over 36,000 units have been produced flying a staggering 300 million flying hours.24 The US military is very familiar with the powerplant

  19. CAS - A Turboprop Solution for the COIN Fight

    Science.gov (United States)

    2009-01-01

    may not be required or even produced by Empresa Brasileira de Aeronautica (Embraer) headquartered in Brazil. attractive... ,,7 Brazil Embraer EMB 314...current applications and over 36,000 units have been produced flying a staggering 300 million flying hours.24 The US military is very familiar with the

  20. Circular Flows: A Teaching Plan.

    Science.gov (United States)

    Trainer, Richard

    The United States is a multi-trillion dollar economy that annually allocates a staggering amount of resources to produce a variety of goods and services for domestic and world consumption, and provides employment and income for millions of individuals. This lesson plan for social studies and economics teachers traces a series of interconnected…

  1. A quantification method for numerical dissipation in quasi-DNS and under-resolved DNS, and effects of numerical dissipation in quasi-DNS and under-resolved DNS of turbulent channel flows

    NARCIS (Netherlands)

    Komen, E.M.J.; Camillo, L.H.; Shams, A.; Geurts, Bernardus J.; Koren, B.

    2017-01-01

    LES for industrial applications with complex geometries is mostly characterised by: a) a finite volume CFD method using a non-staggered arrangement of the flow variables and second order accurate spatial and temporal discretisation schemes, b) an implicit top-hat filter, where the filter length is

  2. Research plays an important role in achieving Zero Hunger | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2017-11-23

    Nov 23, 2017 ... In India, a staggering 56% of women of childbearing age and 70% of children are affected by anemia, which is largely due to iron deficiency. To tackle anemia, researchers in Canada and India developed a method to double-fortify salt with iodine and iron — a potential game-changer in India that is being ...

  3. Human factors in layers of defense in airport security

    NARCIS (Netherlands)

    Andriessen, H.; Van Gulijk, C.; Ale, B.J.M.

    2012-01-01

    Airport security systems are built up out of layers of defence based on the security-in-depth model (Talbot & Jakeman, 2008). The Transport Safety Authority (TSA) in the United States defined a staggering 20 layers of defence to control security risks. This means that not only security personnel is

  4. Modeling insect disturbance across forested landscapes: Insights from the spruce budworm

    Science.gov (United States)

    Brian R. Sturtevant; Barry J. Cooke; Daniel D. Kneeshaw; David A. MacLean

    2015-01-01

    Insects are important disturbance agents affecting temperate and boreal biomes (Wermelinger 2004; Johnson et al. 2005; Cooke et al. 2007; Raffa et al. 2008). Defoliating insects in particular have historically affected a staggering area of North American forests, particularly across the boreal biome (Fig. 5.1). Principal among these boreal forest defoliators is the...

  5. Hadron masses in lattice gauge theories: The inclusions of dynamical fermions

    International Nuclear Information System (INIS)

    Richards, D.G.

    1987-01-01

    Hadron masses are calculated on an 8 3 /times/ 16 lattice using four flavors of staggered fermion to generate the gauge configurations, but using Wilson fermions to calculate the hadron propagators. The identification of a value of the Wilson hopping parameter with the value of the bare quark mass used in the simulations is discussed

  6. The Impact of Staff Training on the Knowledge of Support Staff in Relation to Bereavement and People with an Intellectual Disability

    Science.gov (United States)

    Watters, Laura; McKenzie, Karen; Wright, Rachel

    2012-01-01

    This study aimed to investigate whether a 1-day training course improved support staff knowledge about bereavement and grief in people with a learning disability. A questionnaire based, mixed design was used. Forty-eight participants were randomly assigned to one of two equal groups. A staggered design allowed for group 2 to act both as a control…

  7. Pushing the Entrepreneurial Prodigy: Canadian Aboriginal Entrepreneurship Education Initiatives

    Science.gov (United States)

    Pinto, Laura Elizabeth; Blue, Levon Ellen

    2016-01-01

    Globally, neoliberal education policy touts youth entrepreneurship education as a solution for staggering youth unemployment, a means to bolster economically depressed regions, and solution to the ill-defined changing marketplace. Many jurisdictions have emphasized a need for K-12 entrepreneurial education for the general population, and targeted…

  8. The Inadequacies of "Science for All" and the Necessity and Nature of a Socially Transformative Curriculum Approach for African American Science Education

    Science.gov (United States)

    Mutegi, Jomo W.

    2011-01-01

    "Science for All" is a mantra that has guided science education reform and practice for the past 20 years or so. Unfortunately, after 20 years of "Science for All" guided policy, research, professional development, and curricula African Americans continue to participate in the scientific enterprise in numbers that are staggeringly low. What is…

  9. The collagen microfibril model, a tool for biomaterials scientists

    Science.gov (United States)

    Animal hides, a major byproduct of the meat industry, are a rich source of collagen, a structural protein of the extracellular matrix that gives strength and form to the skin, tendons and bones of mammals. The structure of fibrous collagen, a long triple helix that self-associates in a staggered arr...

  10. Publications | Page 194 | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    This paper exploits the staggered rollout of Vietnam''s hospital autonomization policy to estimate its impacts on several key health sector outcomes including ... and pensions, through proper product design, pricing, development of underwriting standards, determination of asset management strategies, claims analysis, and ...

  11. Symmetry-preserving discretization of Navier-Stokes equations on collocated unstructured grids

    NARCIS (Netherlands)

    Trias, F.X.; Lehmkuhl, O.; Oliva, A.; Pérez-Segarra, C.D.; Verstappen, R.W.C.P.

    2014-01-01

    A fully-conservative discretization is presented in this paper. The same principles followed earlier are generalized for unstructured meshes. Here, a collocated-mesh scheme is preferred over a staggered one due to its simpler form for such meshes. The basic idea behind this approach remains the

  12. Human blood groups: chemical and biochemical basis of antigen specificity

    National Research Council Canada - National Science Library

    Schenkel-Brunner, Helmut

    2000-01-01

    ... of the monograph on the chemistry and biochemistry of human blood groups is being published to honour the 1Oath anniversary of Dr. Karl Landsteiner's discovery of human blood groups here in Vienna. Five years have passed since publication of the first edition, and in this time research on the biochemistry of human blood groups has reached staggering pr...

  13. Process engineering applied to receiving waters

    DEFF Research Database (Denmark)

    Harremoës, Poul

    1973-01-01

    Processes in the media, which recieve waste, must be included in the sphere of interest within industry's environmental consciousness. Pollution problems are not very simple and should thus not be dealt with in too simple a fashion. Chemical engineers are very well suited to deal with the stagger...

  14. Sadhana | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    The Hamilton–Jacobi type equation for the transport of level set function is carried out by a high resolution fifth-order accurate WENO scheme. For efficient implementation of the WENO scheme we have proposed grid staggering for the level set function. The solution of the pressure Poisson equation is obtained using an ...

  15. Epidemiological, Clinical and Pathological findings of Oedema ...

    African Journals Online (AJOL)

    The clinical manifestation was combination of the following; anorexia, staggering gait, oedema of the eyelids, dropping edematous ears, hoarse sound, tremors, paralysis and recumbency. Marked dyspnea and bluish red discoloration in some cases. The main microscopic findings were subcutaneous oedema of the head, ...

  16. Community-based agricultural interventions in the context of food ...

    African Journals Online (AJOL)

    2010-09-12

    Sep 12, 2010 ... as a feasible contributor to food and nutrition security for the rural poor in South Africa, with particular emphasis on contextual and technical factors. ..... other existing crops. A crop rotation system is recommended for soil improvement and pest control. Staggered planting, which entails small, regular.

  17. E-Waste and Harm to Vulnerable Populations : A Growing Global Problem

    NARCIS (Netherlands)

    Heacock, Michelle; Kelly, Carol B; Asante, Kwadwo A; Birnbaum, Linda S; Bergman, Ake L; Bruné, Marie-Noel; Buka, Irena; Carpenter, David O; Chen, Aimin; Huo, Xia; Kamel, Mostafa; Landrigan, Philip J; Magalini, Federico; Diaz-Barriga, Fernando; Neira, Maria; Omar, Magdy; Pascale, Antonio; Ruchirawat, Mathuros; Sly, Leith; Sly, Peter D; Van den Berg, Martin; Suk, William A

    BACKGROUND: Electronic waste (e-waste) is produced in staggering quantities, estimated globally to be 41.8 million tonnes in 2014. Informal e-waste recycling is a source of much-needed income in many low- to middle-income countries. However, its handling and disposal in underdeveloped countries is

  18. Linear and Differential Ion Mobility Separations of Middle-Down Proteoforms

    DEFF Research Database (Denmark)

    Garabedian, Alyssa; Baird, Matthew A; Porter, Jacob

    2018-01-01

    Comprehensive characterization of proteomes comprising the same proteins with distinct post-translational modifications (PTMs) is a staggering challenge. Many such proteoforms are isomers (localization variants) that require separation followed by top-down or middle-down mass spectrometric analys...

  19. Ising and Bloch domain walls in a two-dimensional parametrically driven Ginzburg-Landau equation model with nonlinearity management

    DEFF Research Database (Denmark)

    Gaididei, Yu. B.; Christiansen, Peter Leth

    2008-01-01

    We study a parametrically driven Ginzburg-Landau equation model with nonlinear management. The system is made of laterally coupled long active waveguides placed along a circumference. Stationary solutions of three kinds are found: periodic Ising states and two types of Bloch states, staggered and...

  20. Challenging Corruption in Asia : Case Studies and a Framework for Action

    OpenAIRE

    Bhargava, Vinay; Bolongaita, Emil

    2004-01-01

    At the economic level, corruption is seen as a contributing factor to the East Asian financial crisis. The crisis focused people's attention on the staggering impact of corruption, particularly in Indonesia, the Republic of Korea, and Thailand. The interlocking relationship of business and government were previously viewed as part of the way of doing business and practicing politics-a usef...

  1. Overcoming the learning curve in hand-assisted laparoscopic live ...

    African Journals Online (AJOL)

    The demand for kidneys in South Africa is staggering. Only 38% of the kidney transplants done in 2008 were from related living donors. Laparoscopic living donor nephrectomy has been shown to have the advantages of decreased postoperative pain, better cosmesis and a quicker return to work when compared with the ...

  2. Multiple-bolted joints in wood members : a literature review

    Science.gov (United States)

    Peter James Moss

    1997-01-01

    This study reviewed the literature on experimental and analytical research for the connection of wood members using multiple laterally loaded bolts. From this, the influence of geometric factors were ascertained, such as staggered and aligned fasteners, optimum fastener configurations, row factors and length-to-diameter bolt ratios, spacing, end and edge distances, and...

  3. Changing Tables and Changing Culture: Pregnancy, Parenting, and First-Year Writing

    Science.gov (United States)

    Comer, Denise

    2009-01-01

    Over the past seven years, the 59 full-time faculty of Duke University's first-year writing faculty have birthed, fathered, or adopted 22 babies. What makes this faculty birth rate so staggering is not only that it nearly triples the United States' national average, but also that it differentiates their program from so many other spaces in…

  4. An Analysis of Chinese Foreign Direct Investment (FDI) in Sub ...

    African Journals Online (AJOL)

    user

    In line with this,. China has bilateral trade and economic cooperation with many sub-Saharan. African countries. 4.2 Trends of Chinese FDI across sectors and Countries. China has become the leading country in foreign direct investment in Africa. During the year 2011, trade between Africa and China increased a staggering.

  5. Book review of "Harvestmen: The Biology of the Opiliones"

    Science.gov (United States)

    This is a review of the book Harvestmen by Pinto-da-Rocha et al (eds.), which is a wonderfully balanced and staggeringly complete treatment that covers the gauntlet of taxonomy and systematics, internal physiology, ecology, and behavior of Opiliones. In addition to the breadth of material presented ...

  6. Precursor of pion condensation: The softening of the quasi-elastic peak

    International Nuclear Information System (INIS)

    Alberico, W.M.; Ericson, M.; Molinari, A.

    1980-01-01

    The phase transition of pion condensation is heralded in the disordered phase by an increase in the life time of the fluctuations for the staggered magnetization. This precursor phenomenon entails, in ordinary nuclei, a showing down of the nuclear quasi-elastic response when observed with spin-sensitive probes. (orig.)

  7. Computational mechanics in civil engineering (CMC). Fire - Heat transfer - Stress analysis

    NARCIS (Netherlands)

    Hendriks, M.A.N.; H¢iseth, K.V.; Hynne, T.; ¥verli, J.A.

    1999-01-01

    engineering, especially related to integrated analysis [1]. That is, analysis where two or more interacting effects or phenomena are analysed either staggered or simultaneously. CMC contains five main projects where frequently encountered problems in civil engineering will be treated by an

  8. Small mammals of the Eastern Arc Mountains, Tanzania | Stanley ...

    African Journals Online (AJOL)

    The Eastern Arc Mountains (EAM) contain some of the most biologically diverse and endemic-rich montane ecosystems in all of Africa. Because of the staggering degree of biodiversity, how little we know about the biota of the EAM and the rapid degradation of the remaining montane forests of these mountains, we are ...

  9. Laser spectroscopy of francium isotopes at the borders of the region of reflection asymmetry

    CERN Document Server

    Budinčević, I; Bissell, M L; Cocolios, T E; de Groote, R P; De Schepper, S; Fedosseev, V N; Flanagan, K T; Franchoo, S; Garcia Ruiz, R F; Heylen, H; Lynch, K M; Marsh, B A; Neyens, G; Procter, T J; Rossel, R E; Rothe, S; Strashnov, I; Stroke, H H; Wendt, K D A

    2014-01-01

    The magnetic dipole moments and changes in mean-square charge radii of the neutron-rich $^{218m,219,229,231}\\text{Fr}$ isotopes were measured with the newly-installed Collinear Resonance Ionization Spectroscopy (CRIS) beam line at ISOLDE, CERN, probing the $7s~^{2}S_{1/2}$ to $8p~^{2}P_{3/2}$ atomic transition. The $\\delta\\langle r^{2}\\rangle^{A,221}$ values for $^{218m,219}\\text{Fr}$ and $^{229,231}\\text{Fr}$ follow the observed increasing slope of the charge radii beyond $N~=~126$. The charge radii odd-even staggering in this neutron-rich region is discussed, showing that $^{220}\\text{Fr}$ has a weakly inverted odd-even staggering while $^{228}\\text{Fr}$ has normal staggering. This suggests that both isotopes reside at the borders of a region of inverted staggering, which has been associated with reflection-asymmetric shapes. The $g(^{219}\\text{Fr}) = +0.69(1)$ value supports a $\\pi 1h_{9/2}$ shell model configuration for the ground state. The $g(^{229,231}\\text{Fr})$ values support the tentative $I^{\\pi}(^...

  10. Quantitative Study Examining the Relationship between Demographic Factors and Loan Default among 4-Year College Students

    Science.gov (United States)

    Cobb, Ashley K.

    2017-01-01

    The rate of default on college loans in the United States is staggering and poses a major financial threat not only to the students who are unable to repay their student loans but the U.S. economy. For instance, in 2011, borrowers at nonprofit and for-profit 4-year colleges accounted for almost 50% of all federal loan recipients. College students…

  11. Non-isothermal compositional gas flow during carbon dioxide storage and enhanced gas recovery

    DEFF Research Database (Denmark)

    Singh, Ashok; Böettcher, N.; Wang, W.

    2011-01-01

    In this work we present the conceptual modeling and the numerical scheme for carbon dioxide storage into nearly depleted gas reservoirs for enhanced gas recovery reasons. For this we develop non-isothermal compositional gas flow model. We used a combined monolithic / staggered coupling scheme to ...

  12. Majority of Enterprise Resource Planning (ERP) Projects Fail--M-DCPS Is a Rare Exception. Information Capsule. Volume 1108

    Science.gov (United States)

    Blazer, Christie

    2012-01-01

    A high percentage of ERP projects are classified as failures, leaving organizations with only partially functioning systems or, worse yet, with no ERP systems at all. Those that do succeed usually take significantly longer than expected and encounter staggering budget overruns. This Information Capsule summarizes 10 high profile ERP implementation…

  13. Basic and clinical pharmacology of glucocorticosteroids.

    Science.gov (United States)

    Becker, Daniel E

    2013-01-01

    Glucocorticosteroids are a product of the adrenal cortex and perform a staggering number of physiological effects essential for life. Their clinical use is largely predicated on their anti-inflammatory and immunosuppressive properties, but they also have notable efficacy in the prophylaxis of postoperative nausea and vomiting. This article reviews the basic functions of glucocorticoids and their clinical use in dental practice.

  14. Antiferromagnetism and its relation to the superconducting phases of UPt3

    DEFF Research Database (Denmark)

    Isaacs, E.D.; Zschack, P.; Broholm, C.L.

    1995-01-01

    Using magnetic x-ray and neutron diffraction in UPt3, we find that a suppression of the antiferromagnetic scattering intensity in the superconducting phase is due to a reduction in the magnitude of the staggered moment with no change in symmetry. The existence of the suppression as well...

  15. Cost Versus "Cost" of Higher Education

    Science.gov (United States)

    Erskine, Brian M.

    2009-01-01

    It comes as no surprise that the prices being charged for college tuition are out of control. Stories about the staggering price of tuition are commonplace in popular media. Although the supposed explanations for this phenomenon are attributed to issues such as financial aid, lack of government support, and the state of the economy, none seem to…

  16. 16S rRNA targeted DGGE fingerprinting of microbial communities

    NARCIS (Netherlands)

    Tzeneva, V.A.; Heilig, G.H.J.; Vliet, van W.M.; Akkermans, A.D.L.; Vos, de W.M.; Smidt, H.

    2008-01-01

    The past decades have seen the staggering development of molecular microbial ecology as a discipline that uses the detection of so-called biomarkers to monitor microbial communities in environment samples. A variety of molecules can be used as biomarkers, including cell-wall components, proteins,

  17. A survey of lattice results on finite temperature quantum ...

    Indian Academy of Sciences (India)

    vanishing lattice spacing a are controlled by the dimensionless number aT = 1 Nτ this decrease in Tc leads to an even higher computational effort which depends on the number of lattice points in the temporal (temperature) direction Nτ to some large power. Finally, standard (staggered or Wilson) discretizations of fermions ...

  18. Experimental Investigation on Heat Transfer Characteristics of Different Metallic Fin Arrays

    Science.gov (United States)

    Sangewar, Ravi Kumar

    2018-04-01

    The reliability of electronic equipment depends on the reliability of the system. For small applications natural convection cooling is sufficient, but for the electronic equipment having number of heat generating components, forced convection cooling is essential. In number of cases, pin fin arrangement is preferred for augmentation of heat transfer. Here, the performance of pin fin array of copper and aluminum material with in-line, as well as staggered arrangement over a flat plate is studied. Constant heat input was given to the inline, staggered arrangement of copper as well as aluminium pin fin arrays. In the present experimental study, heat input and airflow rates are the variables. It was found that the heat transfer coefficient for staggered array is 15% more than that of the in-line array, at the same time pressure drop across the staggered array is more by 10% than the in-line array. The pressure drop was observed to be increasing with increase in flow rate as expected. Endeavor of the present work is to find the optimum spacing between the fins in an array for maximum heat transfer rate, by investigating the heat transfer characteristics.

  19. Density of states and phase diagram of the antiferromagnetic spin chain with Dzyaloshinsky-Moriya interaction and spin-phonon coupling

    International Nuclear Information System (INIS)

    Wang Qin; Chen Hong; Zheng Hang

    2007-01-01

    The effects of DM interaction on the density-of-states, the dimerization and the phase diagram in the antiferromagnetic Heisenberg chain coupled with quantum phonons have been studied by a nonadiabatic analytical approach. The results show that the effect of the DM interaction is to increase the staggered antisymmetric spin exchange interaction order but to decrease the spin dimerization and their competitions result in the lattice dimerization ordering parameter to increase for large staggered DM interaction parameter β and decrease for small β. A crossover of β exists in which the dimerization ordering parameter changes non-monotonously. As the DM interaction parameter D increases, depending on the appropriate values of spin-phonon coupling, phonon frequency and β, the system undergoes phase transition from spin gapless state to gapped state or reversely and can even reenter between the two states. The relation between the phonon-staggered ordering parameter, the spin-dimer order parameter and the staggered DM interaction order parameter gives clearly their contributing weights to the lattice dimerization

  20. On the role of vaccine dose and antigenic distance in the transmission dynamics of Highly Pathogenic Avian Influenza (HPAI) H5N1 virus and its selected mutants in vaccinated animals

    NARCIS (Netherlands)

    Sitaras, Ioannis

    2017-01-01

    Influenza virus infections can cause high morbidity and mortality rates among animals and humans, and result in staggering direct and indirect financial losses amounting to billions of US dollars. Ever since it emerged in 1996 in Guangdong province, People’s Republic of China, one particular

  1. environmental education and outcomes-based education in south

    African Journals Online (AJOL)

    nebula of confusion. According to Jansen (1997) OBE is being sold as a solution to universal and deeply entrenched peda- gogical problems. He furthermore states that the claim that OBE will bring about a shift from trans- mission modes of teaching to learner centred approaches represents a conceptual leap of stagger-.

  2. Integrating Testing into Software Engineering Courses Supported by a Collaborative Learning Environment

    Science.gov (United States)

    Clarke, Peter J.; Davis, Debra; King, Tariq M.; Pava, Jairo; Jones, Edward L.

    2014-01-01

    As software becomes more ubiquitous and complex, the cost of software bugs continues to grow at a staggering rate. To remedy this situation, there needs to be major improvement in the knowledge and application of software validation techniques. Although there are several software validation techniques, software testing continues to be one of the…

  3. A meshless scheme for incompressible fluid flow using a velocity-pressure correction method

    KAUST Repository

    Bourantas, Georgios

    2013-12-01

    A meshless point collocation method is proposed for the numerical solution of the steady state, incompressible Navier-Stokes (NS) equations in their primitive u-v-p formulation. The flow equations are solved in their strong form using either a collocated or a semi-staggered "grid" configuration. The developed numerical scheme approximates the unknown field functions using the Moving Least Squares approximation. A velocity, along with a pressure correction scheme is applied in the context of the meshless point collocation method. The proposed meshless point collocation (MPC) scheme has the following characteristics: (i) it is a truly meshless method, (ii) there is no need for pressure boundary conditions since no pressure constitutive equation is solved, (iii) it incorporates simplicity and accuracy, (iv) results can be obtained using collocated or semi-staggered "grids", (v) there is no need for the usage of a curvilinear system of coordinates and (vi) it can solve steady and unsteady flows. The lid-driven cavity flow problem, for Reynolds numbers up to 5000, has been considered, by using both staggered and collocated grid configurations. Following, the Backward-Facing Step (BFS) flow problem was considered for Reynolds numbers up to 800 using a staggered grid. As a final example, the case of a laminar flow in a two-dimensional tube with an obstacle was examined. © 2013 Elsevier Ltd.

  4. Now or Never. The Fight Against Pollution.

    Science.gov (United States)

    Halacy , D. S., Jr.

    Documented in this book are the staggering problems of pollution, the facts and figures about pesticides, waste disposal, air, water, noise, and atomic pollution. In asking the question, "Is there a solution?", Mr. Halacy examines what (if anything) is being done to attack the problems, as well as the many promising technological innovations to…

  5. The origin of unequal bond lengths in the C̃ (1)B2 state of SO2: Signatures of high-lying potential energy surface crossings in the low-lying vibrational structure.

    Science.gov (United States)

    Park, G Barratt; Jiang, Jun; Field, Robert W

    2016-04-14

    The C̃ (1)B2 state of SO2 has a double-minimum potential in the antisymmetric stretch coordinate, such that the minimum energy geometry has nonequivalent SO bond lengths. The asymmetry in the potential energy surface is expressed as a staggering in the energy levels of the ν3(') progression. We have recently made the first observation of low-lying levels with odd quanta of v3('), which allows us-in the current work-to characterize the origins of the level staggering. Our work demonstrates the usefulness of low-lying vibrational level structure, where the character of the wavefunctions can be relatively easily understood, to extract information about dynamically important potential energy surface crossings that occur at much higher energy. The measured staggering pattern is consistent with a vibronic coupling model for the double-minimum, which involves direct coupling to the bound 2 (1)A1 state and indirect coupling with the repulsive 3 (1)A1 state. The degree of staggering in the ν3(') levels increases with quanta of bending excitation, which is consistent with the approach along the C̃ state potential energy surface to a conical intersection with the 2 (1)A1 surface at a bond angle of ∼145°.

  6. Might video games help remedy childhood obesity?

    Science.gov (United States)

    Obesity is the most prevalent health problem among children in the United States and globally, leading to diverse health problems and staggering costs. Most child obesity prevention interventions are not working well, or not at all. Part of the problem is that the causes of child obesity are not cle...

  7. Neuroimmune modulation of gut function

    Science.gov (United States)

    There is considerable interest in the mechanisms and pathways involved in the neuro-immune regulation of gut function. The number of cell types and possible interactions is staggering and there are a number of recent reviews detailing various aspects of these interactions, many of which focus on ...

  8. Powerful and Authentic Digital Media and Strategies for Teaching about Genocide and the Holocaust

    Science.gov (United States)

    Manfra, Meghan McGlinn; Stoddard, Jeremy D.

    2008-01-01

    The continued prominence of genocide and Holocaust education, along with the movement toward the affective in social studies curricula, the advent of the Internet, and continued scholarship in the field, has led to the availability of a staggering array of digital resources for teachers (D. S. Symer 2001). These resources have the potential to…

  9. South African Journal for Research in Sport, Physical Education and ...

    African Journals Online (AJOL)

    Kinetics of full scrum and staggered scrum engagement in under 19 schoolboy rugby union players · EMAIL FULL TEXT EMAIL FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. David E Du Toit, Pierre E Olivier, Frederick J Buys, 15-28. http://dx.doi.org/10.4314/sajrs.v27i2.25916 ...

  10. SU(3) breaking and the pseudo-scalar spectrum in multi-taste QCD

    Energy Technology Data Exchange (ETDEWEB)

    Creutz, Michael

    2017-06-18

    Using the Sigma model to explore the lowest order pseudo-scalar spectrum with SU(3) breaking, this talk considers an additional exact "taste" symmetry to mimic species doubling. Rooting replicas of a valid approach such as Wilson fermions reproduces the desired physical spectrum. In contrast, extra symmetries of the rooted staggered approach leave spurious states and a flavor dependent taste multiplicity.

  11. 78 FR 45441 - Sugar Program; Feedstock Flexibility Program for Bioenergy Producers

    Science.gov (United States)

    2013-07-29

    ... removing sugar from the market. CCC may employ several contracting strategies to discover the most cost... sugar purchase strategy of staggering CCC purchases for biofuel as the market unfolds, rather than one... communications (Braille, large print, audio tape, etc.) should contact the USDA Target Center at (202) 720-2600...

  12. Organic nanofibers integrated by transfer technique in field-effect transistor devices

    DEFF Research Database (Denmark)

    Tavares, Luciana; Kjelstrup-Hansen, Jakob; Thilsing-Hansen, Kasper

    2011-01-01

    The electrical properties of self-assembled organic crystalline nanofibers are studied by integrating these on field-effect transistor platforms using both top and bottom contact configurations. In the staggered geometries, where the nanofibers are sandwiched between the gate and the source-drain...

  13. Origin of methyl torsional potential barrier – An overview

    Indian Academy of Sciences (India)

    Unknown

    opposite sign. Interaction 4 in case of ground state of neutral molecule is not relevant. Thus the result of these three interactions is that the eclipsed conformer is preferred over the staggered one. This model has been extended to radical cations, anions and triplet states by Dorigo, Pratt and Houk26 taking into account the ...

  14. Systematic of signature inversion in (h11/2) p⊗(i13/2) n for odd–odd ...

    Indian Academy of Sciences (India)

    Calculations are carried out within the framework of the two quasiparticle plus rotor model (TQPRM) to explain strong odd–even staggering and signature inversion observed in these high- orbitals. The shifting of point of inversion to lower/higher spin with the increase in neutron/proton numbers is well explained by the ...

  15. Dynamical fermions in lattice quantum chromodynamics

    International Nuclear Information System (INIS)

    Szabo, Kalman

    2007-01-01

    The thesis presentS results in Quantum Chromo Dynamics (QCD) with dynamical lattice fermions. The topological susceptibilty in QCD is determined, the calculations are carried out with dynamical overlap fermions. The most important properties of the quark-gluon plasma phase of QCD are studied, for which dynamical staggered fermions are used. (orig.)

  16. Publications | Page 6 | IDRC - International Development Research ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Results 51 - 60 of 6375 ... Nearly one in every four people in Lebanon is a refugee. This number is staggering, yet not entirely unbelievable given the protracted and emerging conflicts in the Middle East. A rapid influx of refugees from Syria has catapulted Lebanon from the 69th largest refugee-hosting country to the third ...

  17. Orientifold Planar Equivalence: The Chiral Condensate

    DEFF Research Database (Denmark)

    Armoni, Adi; Lucini, Biagio; Patella, Agostino

    2008-01-01

    ) representation and $N_f$ flavours of Majorana fermions in the adjoint representation have the same large $N$ value for any value of the mass of the (degenerate) fermions. Assuming the invariance of the theory under charge conjugation, we prove this statement on the lattice for staggered quenched condensates...

  18. Development and utilization of a bovine type I collagen microfibril model

    Science.gov (United States)

    The structure of fibrous collagen, a long triple helix that self-associates in a staggered array to form a matrix of fibrils, fibers and fiber bundles, makes it uniquely suitable as a scaffold for biomaterial engineering. A major challenge for this application is to stabilize collagen structure by m...

  19. Social Media as Collaborative Media in Workplace Learning

    Science.gov (United States)

    Thomas, Kristopher J.; Akdere, Mesut

    2013-01-01

    As a result of rapid changes in technology, much is discussed about the use of social media in branding, marketing, and in general corporate communications. The intensity with which social media tools--blogs, wikis, Twitter, instant messaging (IM) and Facebook, among others--have proliferated is staggering. Increasingly important is the role of…

  20. Many colours influence the shape and development of the plant : steering plants via light colour moves closer

    NARCIS (Netherlands)

    Ieperen, van W.; Heuvelink, E.; Kierkels, T.

    2013-01-01

    The use of LED’s in horticulture is still progressing. And the increasing number of control possibilities is staggering. But the speed at which our knowledge is being transferred into new developments could be faster, certainly when it comes to the influence of light colour. Here is the current

  1. 75 FR 69647 - Renewal of Department of Defense Federal Advisory Committees

    Science.gov (United States)

    2010-11-15

    ...; c. Health research programs and requirements for the treatment and prevention of disease and injury... years. Such appointments will normally be staggered among the Board membership to ensure an orderly... Readiness), shall appoint the President of the Board from the Board membership. The Under Secretary of...

  2. Acute, sub-chronic and chronic toxicity of Solanum incanum L in ...

    African Journals Online (AJOL)

    Signs of cerebellar hyperplasia were manifested in 25%, 75% and 25% of sheep in groups 2, 3, and 4 respectively, manifested by staggering gait, lateral recumbency, leg paddling movements, coma and death. The mortality rate was 25% for group 2 and 100% for groups 3 and 4. All sheep groups had pneumonia, froth in ...

  3. Trends and preferences of Internet participants: differences between SNS users and non-users

    NARCIS (Netherlands)

    Lorenzo-Romero, C.; Constantinides, Efthymios; Alarcón-del-Amo, M.

    2011-01-01

    The staggering growth of online social networking and the potential of Social Networking Sites as marketing channels has become an issue of attention and interest by commercial organizations. This explorative study provides the basis for understanding the nature and behaviour of users of these

  4. Survival and cardioprotective benefits of long-term blueberry enriched diet in dilated cardiomyopathy following myocardial infarction in rats

    Science.gov (United States)

    Background: Despite remarkable progress in treatment of chronic heart failure (CHF) over the last two decades, mortality, personal suffering and cost remain staggering. And effective interventions are still a challenge. Previously we reported that a blueberry-enriched diet (BD) attenuated necroapopt...

  5. Numerical experiments using deflation with the HISQ action

    Science.gov (United States)

    Davies, Christine; DeTar, Carleton; McNeile, Craig; Vaquero, Alejandro

    2018-03-01

    We report on numerical experiments using deflation to compute quark propagators for the highly improved staggered quark (HISQ) action. The method is tested on HISQ gauge configurations, generated by the MILC collaboration, with lattice spacings of 0.15 fm, with a range of volumes, and sea quark masses down to the physical quark mass.

  6. 13 Animal Emergencies That Should Receive Immediate Veterinary Consultation and/or Care

    Science.gov (United States)

    ... has eaten something poisonous (such as antifreeze, xylitol, chocolate, rodent poison, etc.) Seizures and/or staggering Fractured bones, severe lameness or inability to move leg(s) Obvious signs of pain or extreme anxiety Heat stress or heatstroke Severe vomiting or diarrhea – more than ...

  7. Editorial

    Indian Academy of Sciences (India)

    Materials have always defined the technological limits of civi- lization. As humanity, we've progressed from the Stone Age to the Iron Age to today's Polymer Age. We consume a staggering amount of polymers – the annual production of synthetic poly- mers currently exceeds 300 million tons. While this has come.

  8. Hepatitis B surface antigen seropositivity and knowledge of Hepatitis ...

    African Journals Online (AJOL)

    Introduction: Despite its staggering toll on health, diseases arising from hepatitis are largely unknown, unappreciated, undiagnosed and untreated. Many Nigerians are unaware of their hepatitis B status and often present late to hospital with advanced chronic liver disease. The objectives were to determine the hepatitis B ...

  9. Design of novel supramolecular self-assembly creating ...

    Indian Academy of Sciences (India)

    Administrator

    To the best of our knowledge this is the third structure reported in the area of neutral rectangular assembly. The staggered stacking between the 2D sheets makes the structure less intriguing and reducing the cavity size which accommodates two water molecules by O–H… O interaction. Proc. Indian Acad. Sci. (Chem. Sci.) ...

  10. Res Nov 07 Print

    Indian Academy of Sciences (India)

    staggering tools that can tell the similarities and differences among bat populations that look identical otherwise. Protein electrophoresis and ... risk and protection from environmental rigors while external shelters are .... lessly persecuted and destroyed due to misconceived health threats. Besides, in some regions, bats are ...

  11. Mixing and transport during pharmaceutical twin-screw wet granulation: Experimental analysis via chemical imaging

    DEFF Research Database (Denmark)

    Kumar, Ashish; Vercruysse, Jurgen; Toiviainen, Maunu

    2014-01-01

    a significant interaction between screw design parameters (number and stagger angle of kneading discs) and the process parameters (material throughput and number of kneading discs). The results of the study will allow the development and validation of a transport model capable of predicting the RTD and macro...

  12. The Determinants of International Student Mobility Flows: An Empirical Study on the Erasmus Programme

    Science.gov (United States)

    Rodriguez Gonzalez, Carlos; Bustillo Mesanza, Ricardo; Mariel, Petr

    2011-01-01

    The Erasmus Programme for higher education students is supposed to play an important socio-economic role within Europe. Erasmus student mobility flows have reached a relevant level of two million since 1987, boosted in recent years by the enlargement of the programme to eastern countries. Thereafter, it seems that flows have staggered. In this…

  13. Dynamical fermions in lattice quantum chromodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Szabo, Kalman

    2007-07-01

    The thesis presentS results in Quantum Chromo Dynamics (QCD) with dynamical lattice fermions. The topological susceptibilty in QCD is determined, the calculations are carried out with dynamical overlap fermions. The most important properties of the quark-gluon plasma phase of QCD are studied, for which dynamical staggered fermions are used. (orig.)

  14. Nucleon form factors from high statistics mixed-action calculations with 2+1 flavors

    Energy Technology Data Exchange (ETDEWEB)

    Schroers, Wolfram; Edwards, Robert G; Engelhardt, Michael; Fleming, George Taminga; Hagler, Philipp; Lin, Huey-Wen; Lin, Mei-Feng; Meyer, Harvey B; Musch, Bernhard; Negele, John W; Orginos, Kostas; Pochinsky, Andrew V; Procura, Massimiliano; Renner, Dru B; Richards, David G; Syritsyn, Sergey N

    2009-12-01

    We present new high-statistics results for nucleon form factors at pion masses of approximately 290, 350, 500, and 600 MeV using a mixed action of domain wall valence quarks on an improved staggered sea. We perform chiral fits to both vector and axial form factors and compare our results to experiment.

  15. A control volume based finite difference method for solving the equilibrium equations in terms of displacements

    DEFF Research Database (Denmark)

    Hattel, Jesper; Hansen, Preben

    1995-01-01

    This paper presents a novel control volume based FD method for solving the equilibrium equations in terms of displacements, i.e. the generalized Navier equations. The method is based on the widely used cv-FDM solution of heat conduction and fluid flow problems involving a staggered grid formulation....... The resulting linear algebraic equations are solved by line-Gauss-Seidel....

  16. Next Steps in the Journey: Teaching with "Urgency:" A Call for Immediate Actions

    Science.gov (United States)

    Wilhelm, Jeff, Ed.

    2008-01-01

    With a staggering number of students dropping out of school, widespread below-grade reading proficiency, and PISA results showing a demoralizing lag internationally in math, science, and general problem solving, teachers need to exercise all the control available to them to engage students in meaningful learning. Wilhelm suggests six steps…

  17. Technical and institutional constraints of a cotton pest management strategy in Benin

    NARCIS (Netherlands)

    Togbe, C.E.; Zannou, E.T.; Vodouhè, S.; Haagsma, R.; Gbehounou, G.; Kossou, D.K.; Huis, van A.

    2012-01-01

    A pest management strategy entitled Staggered Targeted Control (in French Lutte Étagée Ciblée, known as LEC) has been promoted in Benin since 1988 as an alternative to the conventional spraying strategy in order to reduce production costs and improve cotton yield and quality. Many cotton growers are

  18. The outer vactank, an object of 7.6m diameter and 13m length is built up of three cylindrical parts. The central part that is integral part of the central barrel and the the extension on either side each one 4.5m long. These extensions house the shoulders that will support and prestress the CMS Coil. To weld the extensions onto the central part a full penetration weld of 24m length and 45 mm thickness has to be done by hand from inside and outside the vacuum tank and its deformation is controled permanently.

    CERN Multimedia

    Hubert Gerwig

    2001-01-01

    The outer vacuum tank will hold the coil suspension system and transmits the weight of the inner detectors to the central barrel. Its thickness is staggered. In the central part its thickness is 60 mm and then goes down to 30 mm at the extremity.

  19. Spin transfer and spin pumping in disordered normal metal-antiferromagnetic insulator systems

    Science.gov (United States)

    Gulbrandsen, Sverre A.; Brataas, Arne

    2018-02-01

    We consider an antiferromagnetic insulator that is in contact with a metal. Spin accumulation in the metal can induce spin-transfer torques on the staggered field and on the magnetization in the antiferromagnet. These torques relate to spin pumping: the emission of spin currents into the metal by a precessing antiferromagnet. We investigate how the various components of the spin-transfer torque are affected by spin-independent disorder and spin-flip scattering in the metal. Spin-conserving disorder reduces the coupling between the spins in the antiferromagnet and the itinerant spins in the metal in a manner similar to Ohm's law. Spin-flip scattering leads to spin-memory loss with a reduced spin-transfer torque. We discuss the concept of a staggered spin current and argue that it is not a conserved quantity. Away from the interface, the staggered spin current varies around a 0 mean in an irregular manner. A network model explains the rapid decay of the staggered spin current.

  20. Editorial

    Indian Academy of Sciences (India)

    Here is an important remark he made about his work with. Mark Kac: "This collaboration is a good example to show that two brains can be better than one, since neither of us could have done the work alone". It staggers the imagination that such a tiny land-locked country of just over ten million should bring forth talent in ...

  1. Storytelling Slide Shows to Improve Diabetes and High Blood Pressure Knowledge and Self-Efficacy: Three-Year Results among Community Dwelling Older African Americans

    Science.gov (United States)

    Bertera, Elizabeth M.

    2014-01-01

    This study combined the African American tradition of oral storytelling with the Hispanic medium of "Fotonovelas." A staggered pretest posttest control group design was used to evaluate four Storytelling Slide Shows on health that featured community members. A total of 212 participants were recruited for the intervention and 217 for the…

  2. SAJBL 319.indd

    African Journals Online (AJOL)

    medical negligence courts, adjudication by way of expert screening panels, mediation,[29] periodical or staggered payouts[30] and defensive professional training).[3133] In an attempt to curtail the meteoric rise in legal and insurance costs emanating from medical negligence litigation, it is specifically the implementation of ...

  3. The Economy, Families and Schools

    Science.gov (United States)

    Williamson, Ronald

    2010-01-01

    The recession has impacted American families and the schools their children attend like nothing in recent memory. Many families continue to struggle with the impact of joblessness. The number of homeless children and youth is staggering. Families struggle with access to health care, growing hunger and greater instability in the family unit.…

  4. 21 CFR 500.65 - Epinephrine injection 1:1,000 in 10-milliliter containers for emergency treatment of...

    Science.gov (United States)

    2010-04-01

    ... is packaged in vials not exceeding 10 milliliters and its label bears, in addition to other required... pounds of body weight. Inject subcutaneously”. (c) The labeling must also bear a description of the... breathing, muscular tremors, staggering gait, and collapse with death following. These symptoms may appear...

  5. Rural social security for Zimbabwe: Challenges and opportunities for ...

    African Journals Online (AJOL)

    For them, the remaining sources of livelihood now reside in non-formal social security arrangements anchored upon a staggering cultural base being eroded by the fast encroaching tide of neoliberal individualistic ways of life. Regrettably, government has got no institutional framework to promote non-formal security ...

  6. Keeping out the oxygen

    NARCIS (Netherlands)

    de Jongh, P.E.

    2011-01-01

    Hydrogen, the lightest of the elements, is expected to play a major role in our future energy economy. Its staggering energy content of 142 MJ kg-1 exceeds that of petroleum by a factor of three. Moreover, the combustion of hydrogen, as well as its use in electricity-producing fuel cells, is not

  7. Allozyme variation in two populations of the Mopane worm, Imbrasia ...

    African Journals Online (AJOL)

    The aims of this study were to determine whether the limited flight ability of moths has an effect on gene flow between two geographically distant I. belina populations, whether there are gene expression differences between moths, worms and pupae and whether staggered generations have different genotypic expressions.

  8. The Storm and Stress of Adolescents with Reading Disabilities ...

    African Journals Online (AJOL)

    Adolescence is a distinct stage of life that has attracted the attention of researchers globally. In 1904, Hall presented the idea of adolescence as a period of storm and stress. Sequel to this idea, increased empirical data caused this notion to stagger. However, the internalizing and externalizing problem behaviours of ...

  9. Credit Supply and Corporate Innovation

    DEFF Research Database (Denmark)

    Amore, Mario Daniele; Schneider, Cédric; Zaldokas, Alminas

    We present evidence that banking development plays a key role in technological progress. We focus on firms’ innovative performance, measured by patent-based metrics, and employ exogenous variations in banking development arising from the staggered deregulation of banking activities across U.S. st...... by a greater ability of deregulated banks to geographically diversify credit risk....

  10. Credit Supply and Corporate Innovation

    DEFF Research Database (Denmark)

    Amore, Mario Daniele; Schneider, Cédric; Žaldokas, Alminas

    2013-01-01

    We present evidence that banking development plays a key role in technological progress. We focus on manufacturing firms' innovative performance, measured by patent-based metrics, and employ exogenous variations in banking development arising from the staggered deregulation of banking activities ...... that these results are strongly driven by a greater ability of deregulated banks to geographically diversify credit risk....

  11. Debonding of short fibres among particulates in a metal matrix composite

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2003-01-01

    A numerical analysis is carried out for the development of damage by fibre-matrix debonding in aluminium reinforced by aligned, short SiC fibres. A unit cell-model that has earlier been applied to study materials with arrays of transversely staggered fibres is here extended to contain a number...

  12. Microfluidic mixing devices for fast optical analysis of liquids

    International Nuclear Information System (INIS)

    Buchegger, W.

    2012-01-01

    For the temporal investigation of chemical reactions a proper mixing of reagents is a prime requirement. Compared to macroscale devices, mixing in microscale underlies a series of new physical effects. The challenge in the design of micromixers is to bring these effects to a beneficial result. The main theme of this thesis is the design of unique microfluidic chips for the investigation of liquids by different analysis techniques. Unique design ideas are evaluated by numerical simulation tools before the realization of the device. Characterization measurements precede experiments with biological samples validating the functional principle and the performance of the proposed microfluidic systems. A continuous flow device, utilizing molecular diffusion for mixing of two liquids, is presented. A multilaminar flow approach is followed to reduce the diffusion length and hence, the mixing time. The combination of multiple fluid layers with an optimized inlet geometry enables the formation of highly uniform fluid layers over the main part of the channel. Thereby, mixing times in the low millisecond range are possible. The micromixer is characterized by a coloration experiment and confocal laser-scanning microscopy supported by software evaluation. Using different materials for fabrication allows the utilization of different optical and spectral analysis techniques. The mixing channel with a height of 8 μm allows the investigation of aqueous solutions by time resolved infrared spectroscopy, despite the high absorption characteristics of water in the infrared region. Design variations with different channel heights allow to optimize the signal intensity for certain applications so that the device is also applicable for Raman spectroscopic measurements. To highlight the feasibility of using the device as fast bioreactor, an enzymatic reaction is investigated by fluorescence microscopy. The microfluidic flow regime allows the generation of highly monodisperse fluidic

  13. Crystal Engineering on Industrial Diaryl Pigments Using Lattice Energy Minimizations and X-ray Powder Diffraction

    International Nuclear Information System (INIS)

    Schmidt, M.; Dinnebier, R.; Kalkhof, H.

    2007-01-01

    Diaryl azo pigments play an important role as yellow pigments for printing inks, with an annual pigment production of more than 50,000 t. The crystal structures of Pigment Yellow 12 (PY12), Pigment Yellow 13 (PY13), Pigment Yellow 14 (PY14), and Pigment Yellow 83 (PY83) were determined from X-ray powder data using lattice energy minimizations and subsequent Rietveld refinements. Details of the lattice energy minimization procedure and of the development of a torsion potential for the biphenyl fragment are given. The Rietveld refinements were carried out using rigid bodies, or constraints. It was also possible to refine all atomic positions individually without any constraint or restraint, even for PY12 having 44 independent non-hydrogen atoms per asymmetric unit. For PY14 (23 independent non-hydrogen atoms), additionally all atomic isotropic temperature factors could be refined individually. PY12 crystallized in a herringbone arrangement with twisted biaryl fragments. PY13 and PY14 formed a layer structure of planar molecules. PY83 showed a herringbone structure with planar molecules. According to quantum mechanical calculations, the twisting of the biaryl fragment results in a lower color strength of the pigments, whereas changes in the substitution pattern have almost no influence on the color strength of a single molecule. Hence, the experimentally observed lower color strength of PY12 in comparison with that of PY13 and PY83 can be explained as a pure packing effect. Further lattice energy calculations explained that the four investigated pigments crystallize in three different structures because these structures are the energetically most favorable ones for each compound. For example, for PY13, PY14, or PY83, a PY12-analogous crystal structure would lead to considerably poorer lattice energies and lower densities. In contrast, lattice energy calculations revealed that PY12 could adopt a PY13-type structure with only slightly poorer energy. This structure was

  14. Drag reduction mechanisms derived from shark skin

    Science.gov (United States)

    Bechert, D. W.; Bartenwerfer, M.; Hoppe, G.; Reif, W.-E.

    A theory of viscous flow on surfaces with small longitudinal riblets is developed. Various riblet shapes immersed in a viscous Couette type shear flow are analyzed, and it is shown that the height by which the riblets protrude into the boundary layer flow is of crucial importance. This protrusion height cannot be increased beyond a certain level for all conceivable straight riblet configurations. Fairly detailed flow data on various riblet configurations are given, including sawtooth, bladelike, scalloped, and convex riblet cross sections. The analytical calculations are confirmed by electrolytical analogy experiments. Staggered short riblets are suggested for circumventing the limit on riblet protrusion height. Electrolytical analogy experiments are used to show that the protrusion height of shark skin may be increased to more than twice the value of conventional straight riblets. It is demonstrated that the skin of fast sharks clearly exhibits the suggested short staggered riblets.

  15. Effects of fin pitch and array of the frost layer growth on extended surface of a heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Dong Keun; Lee, Kwan Soo [Hanyang Univ., Seoul (Korea, Republic of)

    2003-07-01

    This paper presents the effects of the fin array and pitch on the frost layer growth of a heat exchanger. The numerical results are compared with experimental data of a cold plate to validate the present model, and agree well with experimental data within a maximum error of 8%. The characteristics of the frost formation on staggered fin array are somewhat different from those of in-line array. For fin pitch below 10 mm, the frost layer growth of second fin in the staggered array is affected by that of first fin. The heat transfer of single fin deteriorate with decreasing fin pitch regardless of fin array, however, the thermal performance of a heat exchanger, considering increase of heat surface area, becomes better.

  16. Simple countermeasures against the TM110-beam-blowup-mode in biperiodic structures

    International Nuclear Information System (INIS)

    Euteneuer, H.; Herminghaus, H.; Schoeler, H.

    1984-01-01

    The two fundamental methods of fighting beam blow-up in rf-accelerating-structures are staggered detuning and selective Q-spoiling of their higher order modes. Biperiodic structures offer a very simple way of applying the latter technique of the most dangerous TM 110 -like blowup mode at 1.7 times the accelerating frequency: letting this mode propagate but giving a large gap to the TM 110 -passband. This gap must be positive for electric coupling (f(phi=0) =1.7c. With asymmetric coupling elements between the cavities of a structure, one has a simple tool for staggered detuning: a change of the relative orientation of these elements spreads the resonance frequencies not only of the TM 110 -mode, but of at least all dipole modes. (orig.)

  17. Numerical optimization of writer geometries for bit patterned magnetic recording

    Science.gov (United States)

    Kovacs, A.; Oezelt, H.; Bance, S.; Fischbacher, J.; Gusenbauer, M.; Reichel, F.; Exl, L.; Schrefl, T.; Schabes, M. E.

    2014-05-01

    A fully-automated pole-tip shape optimization tool, involving write head geometry construction, meshing, micromagnetic simulation, and evaluation, is presented. Optimizations have been performed for three different writing schemes (centered, staggered, and shingled) for an underlying bit patterned media with an areal density of 2.12 Tdots/in.2. Optimizations were performed for a single-phase media with 10 nm thickness and a mag spacing of 8 nm. From the computed write field and its gradient and the minimum energy barrier during writing for islands on the adjacent track, the overall write error rate is computed. The overall write errors are 0.7, 0.08, and 2.8×10-5 for centered writing, staggered writing, and shingled writing.

  18. The kaon B-parameter from unquenched mixed action lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Aubin, Christopher A.; Laiho, Jack; Van de Water, Ruth S.

    2007-10-01

    We present a preliminary calculation of B{sub K} using domain-wall valence quarks and 2+1 flavors of improved staggered sea quarks. Both the size of the residual quark mass, which measures the amount of chiral symmetry breaking, and of the mixed meson splitting Delta{sub mix}, a measure of taste-symmetry breaking, show that discretization effects are under control in our mixed action lattice simulations. We show preliminary data for pseudoscalar meson masses, decay constants and B{sub K}. We discuss general issues associated with the chiral extrapolation of lattice data, and, as an example, present a preliminary chiral and continuum extrapolation of f{sub pi}. The quality of our data shows that the good chiral properties of domain-wall quarks, in combination with the light sea quark masses and multiple lattice spacings available with the MILC staggered configurations, will allow for a precise determination of B{sub K}.

  19. Antiferromagnetic order in hybrid electromagnetic metamaterials

    Science.gov (United States)

    Miroshnichenko, Andrey E.; Filonov, Dmitry; Lukyanchuk, Boris; Kivshar, Yuri

    2017-08-01

    We demonstrate experimentally a new type of order in optical magnetism resembling the staggered structure of spins in antiferromagnetic ordered materials. We study hybrid electromagnetic metasurfaces created by assembling hybrid meta-atoms formed by metallic split-ring resonators and dielectric particles with a high refractive index, both supporting optically-induced magnetic dipole resonances of different origin. Each pair (or ‘metamolecule’) is characterized by two interacting magnetic dipole moments with the distance-dependent magnetization resembling the spin exchange interaction in magnetic materials. By directly mapping the structure of the electromagnetic fields, we demonstrate experimentally that strong coupling between the optically-induced magnetic moments of different origin can flip the magnetisation orientation in a metamolecule creating an antiferromagnetic lattice of staggered optically-induced magnetic moments in hybrid metasurfaces.

  20. Interfacial characteristics of hybrid nanocomposite under thermomechanical loading

    Science.gov (United States)

    Choyal, Vijay; Kundalwal, Shailesh I.

    2017-12-01

    In this work, an improved shear lag model was developed to investigate the interfacial characteristics of three-phase hybrid nanocomposite which is reinforced with microscale fibers augmented with carbon nanotubes on their circumferential surfaces. The shear lag model accounts for (i) radial and axial deformations of different transversely isotropic constituents, (ii) thermomechanical loads on the representative volume element (RVE), and (iii) staggering effect of adjacent RVEs. The results from the current newly developed shear lag model are validated with the finite element simulations and found to be in good agreement. This study reveals that the reduction in the maximum value of the axial stress in the fiber and the interfacial shear stress along its length become more pronounced in the presence of applied thermomechanical loads on the staggered RVEs. The existence of shear tractions along the RVE length plays a significant role in the interfacial characteristics and cannot be ignored.