618 research outputs found
Near limit premixed flamelets in Hele-Shaw cells
No full textIn this paper we report a preliminary attempt to stabilize near limit premixed flamelets in Hele-Shaw cells. As a quasi-two-dimensional analog of flame balls the flamelet is sustained by diffusive transport alone with fuel supplied from the open ends of the Hele-Shaw cell and heat dissipated to the ambient environment through conduction; radiative heat losses from both phases are neglected. Following Spalding's "one-dimensional idealization" approximation we construct a 2-D model to account for the heat and mass transfer processes in both the gas and the solid phases with the gap height as a parameter controlling the heat exchange rate between the two phases. For each of the three kinds of wall materials considered two steady solution branches are obtained as a function of the gap height one corresponding to large flames and the other to small flames. The large flame branch is critically dependent on the boundary and is therefore of little physical value. Linear stability analysis shows that the small flame branch is unstable to random perturbations. 2-D time dependent numerical simulations indicate that a slightly perturbed steady state on the small flame branch either evolves into a single flamelet drifting to the boundary as a whole or splits into two drifting to the boundary along opposite directions. A partially open square Hele-Shaw combustor has been proposed and is shown to be able to support stabilized flamelets for a certain range of the degree of opening. (C) 2016 by The Combustion Institute. Published by Elsevier Inc
Zb tetraquark channel and BB¯? interaction
No full text37th International Symposium on Lattice Field Theory, LATTICE 2019 -- 16 June 2019 through 22 June 2019 -- Wuhan -- 166411Two tetraquark candidates Zb(10610) and Zb(10650) with flavor structure bb ¯ du ¯ were discovered by Belle experiment in 2011. We present a preliminary Nf = 2 lattice study of the bb ¯ du ¯ system in the approximation of static b quarks, where the total spin of heavy quarks is fixed to one. The ground and the excited eigen-energies are determined as a function of separation r between b and b¯. The lower eigenstates are related to a bottomonium and a pion. One of the higher eigenstates is dominated by BB¯?: its energy is significantly below mB + mB? for r=[0.1,0.4] fm, which suggests sizable attraction. The attractive potential V(r) between B and B¯? is extracted assuming that this eigenstate is related exclusively to BB¯?. Assuming a certain form of the potential at small r < 0.1 fm and solving non-relativistic Schrodinger equation, we find a virtual bound state pole 32?+295 MeV below BB¯? threshold. This pole leads to a narrow peak in the cross-section just above threshold that could be perhaps related to experimental Zb resonances. Given all these approximations, we surprisingly find also a deep bound state 403 ±70 MeV below BB¯? threshold. If such a Zb state exists, it could be experimentally searched in the accurate dependence of rates on ?(1S)?+ invariant mass. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0).Research Agency ARRS, (J1-8137, P1-0035); TUBITAK; Deutsche Forschungsgemeinschaft, DFG; Türkiye Bilimsel ve Teknolojik Araştirma Kurumu, TÜBITA
Card-image public access catalogues (CIPACs) : Issues concerned with their planning and implementation
No full textThis article identifies and discusses the issues and problems that need to be considered in the process of planning and implementing card-image public access catalogues (CIPACs). CIPACs are online library catalogues based on databases of digitised catalogue cards with more or less sophisticated mechanisms for browsing or searching. Solutions of this kind have been implemented by a number of libraries in various countries since the mid-1990s, mainly as inexpensive alternatives to full retrospective conversion of their old catalogues. Based upon a questionnaire and relevant literature, the article looks at the following aspects: cost, conversion speed, universal access, saving of space, preservational aspects, software selection, preparing the card catalogue for conversion, scanning and quality control, image standards, optical character recognition, manual and intellectual input, technological aspects, administrative tools, organisational aspects, peculiarities of old catalogues, presentation of CIPACs to the users, and life expectancy of card-image catalogues
Cellular and molecular mechanisms of immuno-modulation by Ganoderma lucidum
No full textGanoderma lucidum (Leyss. ex Fr.) Karst. (Lingzhi or Reishi) has been used for a long time in China to prevent and treat various human diseases. G. lucidum polysaccharides extracted from G. lucidum are one of efficacious ingredient groups of G. lucidum. A number of reports have demonstrated that G. lucidum polysaccharides modulate immune function both in vivo and in vitro. The immuno-modulating effects of G. lucidum polysaccharides were extensive, including promoting the function of antigen-presenting cells, mononuclear phygocyte system, humoral immunity, and cellular immunity. Cellular and molecular mechanisms, possible receptors involved, and triggered signaling cascades have also been studied in vitro. However, whole animal experiments are still needed to further establish the mechanism of the immunomodulating effects by G. lucidum. Evidence-based clinical trials are also needed.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000232842900003&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Pharmacology & PharmacySCI(E)PubMed87REVIEW2144-1539
Extension of Bertrand's theorem and factorization of the radial Schrodinger equation
No full textThe Bertrand's theorem is extended, i.e., closed orbits still may exist for central potentials other than the power law Coulomb potential and isotropic harmonic oscillator. It is shown that for the combined potential V(r) = W(r) + b/r(2) (W(r) = ar(nu)), when (and only when) W(r) is the Coulomb potential or isotropic harmonic oscillator, closed orbits still exist for suitable angular momentum. The correspondence between the closeness of classical orbits and the existence of raising and lowering operators derived from the factorization of the radial Schrodinger equation is investigated. (C) 1998 American Institute of Physics. [S0022-2488(98)00110-8].http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000076187800011&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Physics, MathematicalSCI(E)7ARTICLE105253-52593
Adiectis passim im margine Responsorum ac Constitutionum capitibus, ex quibus Author suam Epitomen compilauit ...
No full textA Bernardo à Rey, I. V. D. fideliter reddita, ac in Latinam linguam conuersa ; Adiectis passim im margine Responsorum ac Constitutionum capitibus, ex quibus Author suam Epitomen compilauit ...DruckermarkeImpressum im Kolophon: Lvgdvni, Excudebat Ioannes Pvllon, Alias De Trin, Impensis honesti uiri Pauli MirallietiAus dem Vorbesitz des Klosters Rheinau Exemplar der ZB Züric
Vertical profiles of <i>P. donghaiense</i> abundance (left panels) and salinity (right panels) on the transect Zb in seven cruises in 2011.
No full text<p>Vertical profiles of <i>P. donghaiense</i> abundance (left panels) and salinity (right panels) on the transect Zb in seven cruises in 2011.</p
Flame Spread and Extinction Over a Thick Solid Fuel in Low-Velocity Opposed and Concurrent Flows
No full textFlame spread and extinction phenomena over a thick PMMA in purely opposed and concurrent flows are investigated by conducting systematical experiments in a narrow channel apparatus. The present tests focus on low-velocity flow regime and hence complement experimental data previously reported for high and moderate velocity regimes. In the flow velocity range tested, the opposed flame is found to spread much faster than the concurrent flame at a given flow velocity. The measured spread rates for opposed and concurrent flames can be correlated by corresponding theoretical models of flame spread, indicating that existing models capture the main mechanisms controlling the flame spread. In low-velocity gas flows, however, the experimental results are observed to deviate from theoretical predictions. This may be attributed to the neglect of radiative heat loss in the theoretical models, whereas radiation becomes important for low-intensity flame spread. Flammability limits using oxygen concentration and flow velocity as coordinates are presented for both opposed and concurrent flame spread configurations. It is found that concurrent spread has a wider flammable range than opposed case. Beyond the flammability boundary of opposed spread, there is an additional flammable area for concurrent spread, where the spreading flame is sustainable in concurrent mode only. The lowest oxygen concentration allowing concurrent flame spread in forced flow is estimated to be approximately 14 % O-2, substantially below that for opposed spread (18.5 % O-2)
Astronomical Tables And Precepts, For calculating the true Times of New and Full Moons, And shewing the method of projecting Eclipses From The Creation of the World to A.D. 7800 : To which is prefixed, A Short Theory Of The Solar and Lunar Motions
No full textBy James FergusonAus dem Vorbesitz der Naturforschenden Gesellschaft in Zürich Exemplar der ZB Züric
Topological analysis of the EBL model for the chaotic NMR laser
No full textBy determining relative rotation rates of the extended Bloch-type model, a consistent topological description for the model and the chaotic NMR laser at the parameter regime investigated is indicated. A geometrical method for calculating relative rotation rates, which is different from that of constructing the template, is proposed by establishing a symbolic plane in terms of the ordering of forward, and backward sequences encoding unstable periodic orbits.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000076017200011&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Physics, MultidisciplinarySCI(E)1ARTICLE2225-2302
- …
