Fiber contraction

Alexander (1951) observed a maximum contraction in aqueous LiBr for wool fibers of about 14 % which was completely reversed by washing immediately in water. Griffith and Alexander (1957) obtained variable results with this reagent and showed this to be due mainly to the presence of free Br2 or Brs in the solutions. When this was removed the fibers contracted by almost 50 % in boiling LiBr solutions. Fully contracted fibers, however, were no longer capable of even partial length recovery in water. 

The tensions at the optima in Fig. 15 cannot be used to compare the relative magnitudes of the two optima, because (a) they are determined with different single fibers, (b) the number of experiments is small, and (c) different fibers under the same conditions develop very different tensions according to the extent they are denatured. In the experiments of Fig. 8, the tension is measured on the same fibers at different temperatures, and, moreover, on a greater number of fibers. In any case, the correspondence between the temperature coefficients of the tension and hydrolysis rate has not very strict significance, since the one is measured on extended fibers and the other on freely suspended (i.e., contracted) fiber particles (cf. II, 4/). 

Example 2.3. — Let T be a Zariski torsor for a vector bundle over the smooth scheme X over S. Then the morphism T —> X is an A -weak equivalence. It follows from Lemma 2.16 applied to the class C of sheaves represented by smooth schemes over S which are affine (over Spec 2,)), Example 2.2 and the fact that any such torsor is trivial when the base is affine over Sped. More generaUy any smooth morphism Y X of schemes which is a locally trivial fibration in the Nisnevich topology with an A -contractible fiber is an A -weak equivalence. 

Polypropylene fibers are used in every aspect of carpet constmetion from face fiber to primary and secondary backings. Polypropylene s advantages over jute as carpet backing are dimensional stabiUty and minimal moisture absorption. Drawbacks include difficulty in dyeing and higher cost. Bulked-continuous-filament (BCF) carpet yams provide face fiber with improved crimp and elasticity. BCF carpet yams are especially important in contract carpets, characterized by low dense loops, where easy cleaning is an advantage. 

Yarn drying procedures are far more critical than staple drying procedures. AH ceUulosic fibers expand when wetted and contract on drying, the... 

Muscle tissue is unique in its ability to shorten or contract. The human body has three basic types of muscle tissue histologically classified into smooth, striated, and cardiac muscle tissues. Only the striated muscle tissue is found in all skeletal muscles. The type of cells which compose the muscle tissue are known as contractile cells. They originate from mesenchymal cells which differentiate into myoblasts. Myoblasts are embryonic cells which later differentiate into contractile fiber cells. 

Typically, in order for motion to occur, several muscle sets must work together to perform even the simplest movements. The bicep is a two-muscle set the tricep is a three-muscle set. Each set works in tandem. Within each muscle group, muscle fibers obey the aU. or none principle, ie, aU. muscle fibers contract or none contract. Therefore, if the muscle fibers of a muscle group are stimulated enough by nerve impulses to contract, they contract to the maximum. 

Proteins can be broadly classified into fibrous and globular. Many fibrous proteins serve a stmctural role (11). CC-Keratin has been described. Fibroin, the primary protein in silk, has -sheets packed one on top of another. CoUagen, found in connective tissue, has a triple-hehcal stmcture. Other fibrous proteins have a motile function. Skeletal muscle fibers are made up of thick filaments consisting of the protein myosin, and thin filaments consisting of actin, troponin, and tropomyosin. Muscle contraction is achieved when these filaments sHde past each other. Microtubules and flagellin are proteins responsible for the motion of ciUa and bacterial dageUa. 

The Cardiac Cycle. The heart (Eig. lb) performs its function as a pump as a result of a rhythmical spread of a wave of excitation (depolarization) that excites the atrial and ventricular muscle masses to contract sequentially. Maximum pump efficiency occurs when the atrial or ventricular muscle masses contract synchronously (see Eig. 1). The wave of excitation begins with the generation of electrical impulses within the SA node and spreads through the atria. The SA node is referred to as the pacemaker of the heart and exhibits automaticity, ie, it depolarizes and repolarizes spontaneously. The wave then excites sequentially the AV node the bundle of His, ie, the penetrating portion of the AV node the bundle branches, ie, the branching portions of the AV node the terminal Purkinje fibers and finally the ventricular myocardium. After the wave of excitation depolarizes these various stmetures of the heart, repolarization occurs so that each of the stmetures is ready for the next wave of excitation. Until repolarization occurs the stmetures are said to be refractory to excitation. During repolarization of the atria and ventricles, the muscles relax, allowing the chambers of the heart to fill with blood that is to be expelled with the next wave of excitation and resultant contraction. This process repeats itself 60—100 times or beats per minute... 

Chemical modification of the cotton fiber must be achieved within the physical framework of this rather compHcated architecture. Uniformity of reaction and distribution of reaction products are iaevitably iafiuenced by rates of diffusion, swelling and shrinking of the whole fiber, and by distension or contraction of the fiber s iadividual stmctural elements duting finishing processes. 

Junge, D. C., and Boubel, R. W., "Analysis of Control Strategies and Compliance Schedules for Wood Particle and Fiber Dryers," EPA Contract Report No. 68-01-3150. PEDCO Environmental Specialists, Cincinnati, 1976. 

Muscle fibers contain myosin and actin which slide against each other during muscle contraction... 

Thermal oxidizers must be built to provide the residence time and temperatures to achieve the desired destruction efficiency (DE). As such, thermal oxidizers are comparatively larger than catalytic oxidizers since their residence time is two to four times greater. Historical designs of thermal oxidizers were comprised of carbon steel for the outer shell and castable refractory or brick as the thermal liner (a refractory is like a cement, which is put on the inside of the rector shell to act as a thermal insulation barrier). Modern units are designed and built using ceramic fiber insulation on the inside, which is a lightweight material, and has a relatively long life. Old refractory would tend to fail over a period of years by attrition of expansion and contraction. 

For the transverse buckling mode in Figure 3-55, the matrix material expands or contracts in the y-direction. However, the matrix strain in the y-direction (transverse to the fibers) is presumed to be independent of y, i.e., simply twice the two adjacent fiber displacements, v, divided by the original distance between the fibers ... 

The cells of the latter three types contain only a single nucleus and are called myocytes. The cells of skeletal muscle are long and multinucleate and are referred to as muscle fibers. At the microscopic level, skeletal muscle and cardiac muscle display alternating light and dark bands, and for this reason are often referred to as striated muscles. The different types of muscle cells vary widely in structure, size, and function. In addition, the times required for contractions and relaxations by various muscle types vary considerably. The fastest responses (on the order of milliseconds) are observed for fast-twitch skeletal... 

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