35,966 research outputs found

    Thermocapillary induced breakdown of a falling liquid film

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    Hydrodynamic models for effects of thermocapillary instability, film thickness, and heat flux on breakdown of falling liquid film

    Wetting dynamics of evaporating drops on various surfaces

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    Mathematical prediction of evaporating water droplet wetting dynamics on stainless steel, Lucite, Teflon, and copper surface

    Effect of contact angle hysteresis on moving liquid film integrity

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    A study was made of the formation and breakdown of a water film moving over solid surfaces (teflon, lucite, stainless steel, and copper). The flow rate associated with film formation was found to be higher than the flow rate at which film breakdown occurred. The difference in the flow rates for film formation and film breakdown was attributed to contact angle hysteresis. Analysis and experiment, which are in good agreement, indicated that film formation and film breakdown are functions of the advancing and receding angles, respectively

    Resolvable Mendelsohn designs and finite Frobenius groups

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    We prove the existence and give constructions of a (p(k)−1)(p(k)-1)-fold perfect resolvable (v,k,1)(v, k, 1)-Mendelsohn design for any integers v>k≥2v > k \ge 2 with v≡1mod  kv \equiv 1 \mod k such that there exists a finite Frobenius group whose kernel KK has order vv and whose complement contains an element ϕ\phi of order kk, where p(k)p(k) is the least prime factor of kk. Such a design admits K⋊⟨ϕ⟩K \rtimes \langle \phi \rangle as a group of automorphisms and is perfect when kk is a prime. As an application we prove that for any integer v=p1e1…ptet≥3v = p_{1}^{e_1} \ldots p_{t}^{e_t} \ge 3 in prime factorization, and any prime kk dividing piei−1p_{i}^{e_i} - 1 for 1≤i≤t1 \le i \le t, there exists a resolvable perfect (v,k,1)(v, k, 1)-Mendelsohn design that admits a Frobenius group as a group of automorphisms. We also prove that, if kk is even and divides pi−1p_{i} - 1 for 1≤i≤t1 \le i \le t, then there are at least φ(k)t\varphi(k)^t resolvable (v,k,1)(v, k, 1)-Mendelsohn designs that admit a Frobenius group as a group of automorphisms, where φ\varphi is Euler's totient function.Comment: Final versio

    Anomaly induced QCD potential and Quark Decoupling

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    We explore the anomaly induced effective QCD meson potential in the framework of the effective Lagrangian approach. We suggest a decoupling procedure, when a flavored quark becomes massive, which mimics the one employed by Seiberg for supersymmetric gauge theories. It is seen that, after decoupling, the QCD potential naturally converts to the one with one less flavor. We study the NcN_c and NfN_f dependence of the η′\eta^{\prime} mass.Comment: 11 pages, RevTe

    Evaluation and comparison of satellite precipitation estimates with reference to a local area in the Mediterranean Sea

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    Precipitation is one of the major variables for many applications and disciplines related to water resources and the geophysical Earth system. Satellite retrieval systems, rain-gauge networks, and radar systems are complementary to each other in terms of their coverage and capability of monitoring precipitation. Satellite-rainfall estimate systems produce data with global coverage that can provide information in areas for which data from other sources are unavailable. Without referring to ground measurements, satellite-based estimates can be biased and, although some gauge-adjusted satellite-precipitation products have been already developed, an effective way of integrating multi-sources of precipitation information is still a challenge.In this study, a specific area, the Sicilia Island (Italy), has been selected for the evaluation of satellite-precipitation products based on rain-gauge data. This island is located in the Mediterranean Sea, with a particular climatology and morphology, which can be considered an interesting test site for satellite-precipitation products in the European mid-latitude area. Four satellite products (CMORPH, PERSIANN, PERSIANN-CCS, and TMPA-RT) and two GPCP-adjusted products (TMPA and PERSIANN Adjusted) have been selected. Evaluation and comparison of selected products is performed with reference to data provided by the rain-gauge network of the Island Sicilia and by using statistical and graphical tools. Particular attention is paid to bias issues shown both by only-satellite and adjusted products. In order to investigate the current and potential possibilities of improving estimates by means of adjustment procedures using GPCC ground precipitation, the data have been retrieved separately and compared directly with the reference rain-gauge network data set of the study area.Results show that bias is still considerable for all satellite products, then some considerations about larger area climatology, PMW-retrieval algorithms, and GPCC data are discussed to address this issue, along with the spatial and seasonal characterization of results. © 2013 Elsevier B.V
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