Free surfaces smoothing

It is clear from examination of the fracture surface and weld cross sections that the weld was improperly formed, resulting in an irregular plane of unbonded metal. The smoothly rippled, spherical contours in some regions of the fractured area are evidence of solidification of the weld metal along a free surface that was not in contact with the plate. Substantial porosity is apparent. 

Specially formulated polyester resin that is pigmented and contains fillers. Provides a smooth, pore-free surface for the plastic article. 

Observations of smooth spalls in iron provided an early, dramatic demonstration of the importance of release wave behaviors. In 1956, Dally [61E01] reported the existence of remarkably smooth fracture surfaces in explosively compressed steel. The existence of these smooth spalls was a sensitive function of the sample thickness. Analysis and experiments by Erkman [61E01] confirmed that the smooth spalls were associated with interaction of release-wave shocks and shocks from reduction of pressure at free surfaces. These release shocks are a consequence of differences in compressibility at pressures just below and just above the 13 GPa transformation. 

The simulated free surface of liquid water is relatively stable for several nanoseconds [68-72] because of the strong hydrogen bonds formed by liquid water. The density decrease near the interface is smooth it is possible to describe it by a hyperbolic tangent function [70]. The width of the interface, measured by the distance between the positions where the density equals 90% and 10% of the bulk density, is about 5 A at room temperature [70,71]. The left side of Fig. 3 shows a typical density profile of the free interface for the TIP4P water model [73]. 

Very similar to the properties of the free surface are the properties of water near smooth walls, which interact only weakly with water molecules. Many different models have been used, such as hard walls [81-83], exponentially repulsive walls [84-86], and Lennard-Jones potentials of various powers [81,87-96]. 

The principal effect of the presence of a smooth wall, compared to a free surface, is the occurrence of a maximum in the density near the interface due to packing effects. The height of the first maximum in the density profile and the existence of additional maxima depend on the strength of the surface-water interactions. The thermodynamic state of the liquid in a slit pore, which has usually not been controlled in the simulations, also plays a role. If the two surfaces are too close to each other, the liquid responds by producing pronounced density oscillations. 

The flocculation rate dependency on the fractional surface coverage 0 in Equation (1) has been qualitatively confirmed (13, 14), although the maximum rate appears to occur for a surface coverage of less than 50%. The adsorption rate is also a function of 0, and it has been shown (15) for adsorption onto a smooth solid surface that the rate is proportional to the fraction of polymer-free surface area, 1-0. This approach has not... 

Surface area of the reactants For a high-energy reaction to rapidly proceed, the oxidizer must be in intimate contact with the fuel. Decreasing particle size will increase this contact, as will increasing the available surface area of the particles. A smooth sphere will possess the minimum surface area for a given mass of material. An uneven, porous particle will exhibit much more free surface, and consequently will be a much more reactive material. Particle... 

At the simplest level, nanoparticles of hard substances are useful as polishing powders which are able to give very smooth, defect-free surfaces. Indeed, 50 nm nanoparticles of cobalt tungsten carbide are found to be much harder than the bulk material. Therefore, they can be used to make cutting and drilling tools that will last longer. 

However, the flow regime of a film cannot be defined uniquely as laminar or turbulent, as in the case of pipe flow, due to the presence of the free surface. Depending on the values of AFr and JVw , the free surface may be smooth, or covered with gravity waves or capillary or mixed capillary-gravity waves of various types. Thus, under suitable conditions, it is possible to have smooth laminar flow, wavy laminar or turbulent flow, where the wavy flows may be subdivided into gravity or capillary... 

AlGaN alloys doped with Si have been grown by electron cyclotron resonance (ECR) MBE at temperatures between 700 and 800°C [23,24], These layers were found to have net carrier concentrations of 1016 to 1019 cm 3 as measured by the Hall effect technique. The carrier concentration varies only slightly on alloying up to 25% Al. The samples were found to be smooth and free from cracks. Murakami et al also reported crack-free surfaces of Si doped Alo.1Gao.9N with a carrier concentration of up to 2 x 1018 cm 3 [25],... 

In order to get complementary information on the evolution of the shape of the extrudate at the die exit, photographs were taken simultaneously for each flow condition. Examples of free surfaces build establishments are presented in Figs. 7 and 8, respectively for smooth (long dies and low shear rate) and for stronger flow conditions (short die and high shear rate). It is clear that strong flow conditions enhance the differences between LLDPE and LDPE. While LLDPE exhibits rapid evolution towards a constant diameter, instabilities occur for LDPE, which correspond to the onset of melt fracture. 

The Reynolds number for condensation on the outer surfaces of vertical tube or plates increases in the flow direction due to the increase of the liquid filn thickness S. The flow of liquid film exhibits different regimes, depending 01 the value of the Reynolds number. It is observed that the outer surface of th liquid film remains smooth and wave-free for about Re < 30, as shown ii Fig. 10 -23, and thus the flow is clearly laminar. Ripples or waves appear 01 the free surface of the condensate flow as the Reynolds number increases, anr the conden.sale flow becomes fully turbulent at about Re 1800. The con densate flow is called wavy-laminar in the range of 450 < Re < 1800 an turbulent for Re > 1800. However, some disagreement exists about the valu of Re at which the flow becomes wavy-laminar or turbulent. 

The simplest possible case of a gas-solid interaction for physical adsorption is that of a molecule interacting with a smooth hard wall. The wall can be planar, as for a free surface or a slit pore, or it can be cylindrical or some other shape for a pore. These cases have been extensively studied by Monte Carlo and molecular dynamics with results that show that such a gas-solid interaction gives a strongly structured fluid that can be best described as a series of layers that follow the contour of the wall. The sharpness of the density variations that define these layers increases as the overall density of the adsorbed film increases and decreases with increasing distance from the wall. 

Application of the hot asphalt on a floor (or other horizontal flat surface) is by pouring the material on the surface and spreading it with a squeegee-usually wood, and approximately 18 in. long. Observe workmanship carefully to be certain the mechanic is providing a glassy, smooth and pinhole and bubble (or blister) free surface. If there are bubbles or blisters in the membrane, the job must be stopped until they have been removed and the membrane repaired. (See the section on Asphalt for procedure.)... 

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