Peel, peeling

Peeling. Peeling is the term applied to the stepwise depolymerization of polysaccharides from the reducing end groups under alkaline conditions. In conjunction with the formation of new end groups by alkaline hydrolysis of glycosidic bonds, the degradation of the polysaccharides can be extensive. 

When you eat raw fruit or vegetables that can be peeled, peel them yourself. (Wash your hands with soap first.) Do not eat the peelings. 

Peel Peel is the force applied to a joint in which one or both of the adherends is flexible and in which the force is concentrated at a boundary line. ... 

Peel ( ) Peel strength for stated test sample configuration, e.g. T peel, floating roller, bell, sandwich, etc. Units vary for different test pieces. 

Cure Shrinkage S/Z/cones - % after cure, often linear value. Peel Peel Strength. 

Modified TCA peels Peel components Speed of TCA peel... 

It is a common misconception that for high peel force an adhesive must be very strong. To the contrary, often weaker adhesives exhibit much higher peel. Peel force is a measure of the work done while removing the adhesive its units are force/width of tape. This corresponds to the energy consumed on peeling per unit area of adhesive bond. 

The usual practical situation is that in which two solids are bonded by means of some kind of glue or cement. A relatively complex joint is illustrated in Fig. XII-14. The strength of a joint may be measured in various ways. A common standard method is the peel test in which the normal force to separate the joint... 

Fig. XII-15. Diagram of peel test. A and B, adhesive joint C, double Scotch adhesive tape and D, rigid support. (From Ref. 107. By permission of IBC Business Press, Ltd.)...

Other veneers for backs and cores, or in the case of the tropical luauns, are almost always peeled on a rotary lathe. In this process, the log is rotated against along, stationary knife and the log is essentially "unroUed" in along, thin sheet. These sheets are called rotary-cut veneers. 

After the block is chucked in the lathe, the lathe turns the block against the knife and peels the veneer in a continuous sheet as the knife moves toward the center of the block. When the knife cannot advance further without moving into the metal chucks, the lathe is stopped, the core of the block is dropped, the lathe is recharged, and the cycle repeated. 

Fig. 13. Scanning electron microscope (sem) photographs of Parylene C-coated printed circuit conductor peeled to demonstrate the adhesion of the...

The cured polymers are hard, clear, and glassy thermoplastic resins with high tensile strengths. The polymers, because of their highly polar stmcture, exhibit excellent adhesion to a wide variety of substrate combinations. They tend to be somewhat britde and have only low to moderate impact and peel strengths. The addition of fillers such as poly (methyl methacrylate) (PMMA) reduces the brittleness somewhat. Newer formulations are now available that contain dissolved elastomeric materials of various types. These mbber-modifted products have been found to offer adhesive bonds of considerably improved toughness (3,4). 

The routine compositional and functional testing done on the adhesives includes gas chromatographic testing for purity, potentiometric titrations for acid stabilizer concentrations, accelerated thermal stabiUty tests for shelf life, fixture time cure speed tests, and assorted ASTM tests for tensile shear strengths, peel and impact strengths, and hot strengths. 

Fig. 2. Illustrations of forces to which adhesive bonds are subjected, (a) A standard lap shear specimen where the black area shows the adhesive. The adherends are usually 25 mm wide and the lap area is 312.5 mm. The arrows show the direction of the normal apphcation of load, (b) A peel test where the loading configuration, shown by the arrows, is for a 180° peel test, (c) A double cantilever beam test specimen used in the evaluation of the resistance to crack propagation of an adhesive. The normal application of load is shown by the arrows. This load is appHed by a tensile testing machine or other...

Peel tests are accompHshed using many different geometries. In the simplest peel test, the T-peel test, the adherends are identical in size, shape, and thickness. Adherends are attached at thek ends to a tensile testing machine and then separated in a "T" fashion. The temperature of the test, as well as the rate of adherend separation, is specified. The force requked to open the adhesive bond is measured and the results are reported in terms of newtons per meter (pounds per inch, ppi). There are many other peel test configurations, each dependent upon the adhesive appHcation. Such tests are well described in the ASTM hterature. 

Adhesive type Shear load, MPa Peel load, N/m ... 

The physical properties of polyurethane adhesives result from a special form of phase separation which occurs in the cross-linked polyurethane stmcture. The urethane portions of polyurethanes tend to separate from the polyol portion of the resin, providing good shear strength, good low temperature flexibiUty, and high peel strength. Catalysts such as dibutyltin dilaurate [77-58-7], stannous octoate [1912-83-0], l,4-diazabicyclo[2.2.2]octane... 

Pectin, which occurs in most plants as the glue which binds the cells together, is extracted commercially from citms peel and has been extracted from apple pomace. It is suggested for many no-fat products including sauces, desserts, and dressings. 

Other important properties that can be measured in the laboratory include sealabiHty, printabiHty, or coating adhesion. Many of these tests have been developed by the film manufacturer in cooperation with customers and are specifically designed to measure product performance in the end use. Some tests, like sealabiHty, can be standardi2ed to time, pressure, and temperature of sealing with instmment-measured peel values, but other tests are subjective, such as evaluations of printing loss to puUoff by adhesive tape. 

The filter usually has an endless cloth, traveling intermittently between the plates via roUers, to peel off cakes. Unfortunately, if the cloth is damaged anywhere, the whole cloth must be replaced, which is a difficult process. Each time the filter cloth zigzags through the filter, the filtering direction is reversed this tends to keep the cloth clean. Most of these filters incorporate membranes for mechanical expression, and cakes sometimes stick to the membranes and remain in the chamber after discharge. Some vertical filters are available with a separate cloth for each frame. The cloths maybe disposable and such filters are designed to operate with or without filter aids. 

Another group of natural flavoring ingredients comprises those obtained by extraction from certain plant products such as vanilla beans, Hcotice root, St. John s bread, orange and lemon peel, coffee, tea, kola nuts, catechu, cherry, elm bark, cocoa nibs, and gentian root. These products are used in the form of alcohohc infusions or tinctures, as concentrations in alcohol, or alcohol—water extractions termed fluid or soHd extracts. Official methods for their preparation and specifications for all products used in pharmaceuticals are described (54,55). There are many flavor extracts for food use for which no official standards exist the properties of these are solely based on suitabiUty for commercial appHcations (56). 

The most important considerations in marketing and estabUshing a crop from a new source are constancy of supply and quahty. Eor some spices, it is difficult to reduce labor costs, as some crops demand individual manual treatment even if grown on dedicated plantations. Only the individual stigmas of the saffron flower must be picked cinnamon bark must be cut, peeled, and roUed in strips mature unopened clove buds must be picked by hand and orchid blossoms must be hand pollinated to produce the vanilla bean. 

Ethylene—tetrafluoroethylene copolymers respond weU to melt bonding to untreated aluminum, steel, and copper with peel strengths above 3.5 kN/m (20 Ibf/in.). Eor melt bonding to itself, hot-plate welding is used. The material is heated to 271—276°C, and the parts are pressed together during cooling. 

Essentia.1 Oils. Essential oils (qv) are extracted from the flower, leaf, bark, fmit peel, or root of a plant to produce flavors such as mint, lemon, orange, clove, cinnamon, and ginger. These volatile oils are removed from plants either via steam distillation, or using the cold press method, which avoids heat degradation. Additional processing is sometimes employed to remove the unwanted elements from the oils, such as the terpenes in citms oils which are vulnerable to oxidation (49,50). 

The extension of the useful storage life of plant and animal products beyond a few days at room temperature presents a series of complex biochemical, physical, microbial, and economic challenges. Respiratory enzyme systems and other enzymes ia these foods continue to function. Their reaction products can cause off-davors, darkening, and softening. Microbes contaminating the surface of plants or animals can grow ia cell exudates produced by bmises, peeling, or size reduction. Fresh plant and animal tissue can be contaminated by odors, dust, iasects, rodents, and microbes. 

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