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21.
Dynamics of ice nucleation on water repellent surfaces 总被引:3,自引:0,他引:3
Alizadeh A Yamada M Li R Shang W Otta S Zhong S Ge L Dhinojwala A Conway KR Bahadur V Vinciquerra AJ Stephens B Blohm ML 《Langmuir : the ACS journal of surfaces and colloids》2012,28(6):3180-3186
Prevention of ice accretion and adhesion on surfaces is relevant to many applications, leading to improved operation safety, increased energy efficiency, and cost reduction. Development of passive nonicing coatings is highly desirable, since current antiicing strategies are energy and cost intensive. Superhydrophobicity has been proposed as a lead passive nonicing strategy, yet the exact mechanism of delayed icing on these surfaces is not clearly understood. In this work, we present an in-depth analysis of ice formation dynamics upon water droplet impact on surfaces with different wettabilities. We experimentally demonstrate that ice nucleation under low-humidity conditions can be delayed through control of surface chemistry and texture. Combining infrared (IR) thermometry and high-speed photography, we observe that the reduction of water-surface contact area on superhydrophobic surfaces plays a dual role in delaying nucleation: first by reducing heat transfer and second by reducing the probability of heterogeneous nucleation at the water-substrate interface. This work also includes an analysis (based on classical nucleation theory) to estimate various homogeneous and heterogeneous nucleation rates in icing situations. The key finding is that ice nucleation delay on superhydrophobic surfaces is more prominent at moderate degrees of supercooling, while closer to the homogeneous nucleation temperature, bulk and air-water interface nucleation effects become equally important. The study presented here offers a comprehensive perspective on the efficacy of textured surfaces for nonicing applications. 相似文献
22.
John G. Conway Jean Blaise Jean Vergés 《Spectrochimica Acta Part B: Atomic Spectroscopy》1976,31(1):31-47
The spectrum of curium-244 has been observed on the high resolution Fourier-transform spectrometer at Laboratoire Aimé Cotton. An electrodeless lamp containing 50 μg of CmI3 was run for 12 hr and 800,000 points were taken. A total of 1743 lines have been ascribed to curium and 87% of the lines have been assigned to transitions between known energy levels. 相似文献
23.
Measurements of salting-out of Ar by NH 4 Br and a series of homologous symmetrical tetraalkylammonium bromides in water are reported and discussed. A new gas-solubility apparatus is used enabling the solubility to be derived from a number of measurements on the same gas-solution sample at various pressures, rather than from a single measurement on each solution. Unexpectedly large salting-out effects are observed which increase with cation size. Electrostatic and nonelectrostatic effects are examined in relation to the ionic-volume behavior in water and methanol as a basis for discussion of the results. The relative electrostrictions of the TAA and Br? ions in these two solvents are compared. Calculations based on electrostatic and scaled particle theory are compared, and it is concluded that the latter treatment obscures the electrochemical factors of essential interest in solute/solvent distribution about ions in solution. 相似文献
24.
Journal of the Operational Research Society - 相似文献
25.
This investigation concerns the application of a special method of successive approximations to the solution of a practically motivated, nonlinear problem of the bending of a uniformly loaded circular plate supported on a concentric circle. Numerical results are obtained for a range of plate-radius/support-radius ratios, and the former are found to be in good agreement with the results of experiments. 相似文献
26.
Hawkes NC Stratton BC Tala T Challis CD Conway G DeAngelis R Giroud C Hobirk J Joffrin E Lomas P Lotte P Mailloux J Mazon D Rachlew E Reyes-Cortes S Solano E Zastrow KD 《Physical review letters》2001,87(11):115001
Simultaneous current ramping and application of lower hybrid heating and current drive (LHCD) have produced a region with zero current density within measurement errors in the core ( r/a< or =0.2) of JET tokamak optimized shear discharges. The reduction of core current density is consistent with a simple physical explanation and numerical simulations of radial current diffusion including the effects of LHCD. However, the core current density is clamped at zero, indicating the existence of a physical mechanism which prevents it from becoming negative. 相似文献
27.
Tkaczyk S Tollefson K Tollestrup A Toyoda H Trischuk W de Troconiz JF Tseng J Turini N Ukegawa F Valls J Vejcik S Velev G Vidal R Vilar R Vologouev I Vucinic D Wagner RG Wagner RL Wahl J Wallace NB Walsh AM Wang C Wang CH Wang MJ Watanabe T Waters D 《Physical review letters》2000,84(6):1110-1115
We search for color singlet technirho and technipion production in p&pmacr; collisions at sqrt[s] = 1.8 TeV recorded with the Collider Detector at Fermilab. These exotic technimesons are present in a model of walking technicolor. The signatures studied are lepton plus two jets plus E(T) and multijet final states. No excess of events is seen in either final state. We set an upper limit on the technirho production cross section and exclude a region in the technipion mass versus technirho mass plane. 相似文献
28.
Toyoda H Trischuk W de Troconiz JF Tseng J Turini N Ukegawa F Vaiciulis T Valls J Vejcik S Velev G Vidal R Vilar R Volobouev I Vucinic D Wagner RG Wagner RL Wahl J Wallace NB Walsh AM Wang C Wang CH Wang MJ Watanabe T Waters D Watts T Webb R 《Physical review letters》2000,84(22):5043-5048
We report results from a study of events with a leading antiproton of beam momentum fraction 0.9057 GeV. Using the dijet events, we evaluate the diffractive structure function of the antiproton and compare it with expectations based on results obtained in diffractive deep inelastic scattering experiments at the DESY ep collider HERA. 相似文献
29.