Surface smoothness

Specific terms have been designated according to the function and composition of various roUs. Steel roUs that impose pressure, transmit heat, and emboss a pattern onto the fabric are known as pattern roUs. Flexible surface roUs that transport the fabric and permit pressure transmission to the fabric are termed bowl roUs or bowls. Bowl roUs are usually larger in diameter than pattern roUs. The material used to make these types of roUs is chosen according to the depth of surface smoothness to be placed on the fabric being calendered, and must be compatible with the pattern roU. Cellulose pulp, cotton, wool, cotton—wool mixtures, com husk, and various polymer materials are used as fillers for the roU surface compound. 

Refining is used to develop the desired pulp drainage properties and control the foUowiag sheet properties bulk and density, strength, surface smoothness, porosity, and printing characteristics. 

After the wood particles are coated with resia, the particles are uniformly distributed iato a board by an air laid process. The art of the process is ia controlling and getting a uniform distribution of the wood particles by blowiag them out onto a collection chain. After forming the board shape it is moved to hot presses where the wood particles are consoHdated and the resia cured. From the hot presses the boards move to trim saws where the boards are cut square to their fiaal size. Ia some cases, the boards are sanded to final thickness and surface smoothness. 

Of obvious importance to aircraft is the smoothness of exterior surfaces. Smooth aerodynamic surfaces reduce aerodynamic drag, resulting in higher airspeeds and increased efficiency. Mechanical fasteners, even countersunk flush fasteners, introduce disruptions in the airflow over the exterior surface. Even the slight deformation of thin sheets around fasteners produces drag. Adhesively bonded structure has no fasteners to disrupt airflow and is more capable of producing the smooth continuous contours that are so common on aircraft. 

As the surface smoothing and levelling effects are somewhat limited, the use of acid cleaners prior to anodising or electropainting, where surface defects can be enhanced, is not common. 

High-pressure structural foam products have generally been found to require little or no postfinishing. Although high-pressure foam products may exhibit visual splay, their surface smoothness is maintained and no sanding or filling is required. 

Because of the high quality of surface smoothness of films, wind-up onto rollers causes adjacent film layers to adhere together, either by static electricity or cold-flow (creep). This is overcome by adding finely divided fillers (less than 1 pm diameter) of, for example, chalk, silica, crosslinked polyacrylates, which roughen the surface allowing entrapped air to keep the successive layers apart. 

The majority of the aforementioned capsules were either not sufficiently mechanically stable or suffered from other surface or matrix related deficiencies. These deficiencies include poor morphology, such as capsule sphericity and surface smoothness, which result from an osmolar imbalance. Membranes are also often leaky (an internal polymer slowly diffuses out through the capsule wall) or shrink in either PBS or in culture media over a period of a few hours. Exceptionally, some capsules are observed to swell excessively and burst. Furthermore, some complex membranes, although stable in water, dissolve over several days upon a contact with culture media. This is true for pectin based capsules (pectin/calcium salt) and for alginate-chitosan membranes and maybe a consequence of the polycation substitution by electrolytes present in the media [10]. In order to improve the existing binary capsules several approaches, both traditional and novel, have been considered and tested herein. These are discussed in the following sections. 

However, an intrinsic physiological requirement for the cornea is the maintenance of its transparency, ensuring proper vision. This clarity as well as maintenance of the corneal shape (surface smoothness and total thickness) is critical to refraction. The unique transparency of corneal tissues is strongly dependent on their avascularity and a functionally intact endothelium, which are crucial for the maintenance of both stromal clarity and thickness by regulating corneal hydration. Macroscopically, the cornea is a transparent and avascular tissue... 

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