Contraction driving

While many properties of EAPs are also found in other materials, EAPs exhibit unique combinations of properties that have led to use in a variety of applications. Perhaps the most promising feature of EAPs is the switchable nature of many of the properties. The ability to reversibly switch EAPs between insulating and conducting, opaque and transparent, absorptive and emissive, or expanded and contracted drives much of the current EAP research. 

One of the primary objectives of production operations is to deliver product at the required rate and quality. Therefore the product quality specification and any agreed contract terms will drive the activities of the production operations department, and will be a starting point for determining the preferred mode of operation. The specifications, such as delivery of stabilised crude with a BS W of less than 0.5%, and a salinity of 70 g/m, ... 

Market forces determine the demand for a product, and the demand will be used to forecast the sales of hydrocarbons. This will be one of the factors considered by some governments when setting the production targets for the oil company. For example, much of the gas produced in the South China Sea is liquefied and exported by tanker to Japan for industrial and domestic use the contract agreed with the Japanese purchaser will drive the production levels set by the National Oil Company. 

The drive for these additional requirements has come not from the suppliers but from users, such as the automotive, utilities, telecommunications, software, and aerospace industries which purchase millions of products and services used to produce the goods and services they provide to the consumer. Rather than invoke customer-specific conditions in each contract, the larger purchasers perceive real benefits from agreeing common quality system requirements for their industry sector. Quite often a supplier will be supplying more than one customer in a particular sector and hence costs increase for both the supplier and the customer if the supplier has to meet different requirements that serve the same objective. All customers desire products and services that consistently/ meet their requirements. While the physical and functional requirements for the product or service will differ, the requirements governing the manner in which their quality is to be achieved, controlled, and assured need not differ. Differences in quality system requirements may arise between industry sectors where the technology, complexity, and risks are different. 

Certain proteins endow cells with unique capabilities for movement. Cell division, muscle contraction, and cell motility represent some of the ways in which cells execute motion. The contractile and motile proteins underlying these motions share a common property they are filamentous or polymerize to form filaments. Examples include actin and myosin, the filamentous proteins forming the contractile systems of cells, and tubulin, the major component of microtubules (the filaments involved in the mitotic spindle of cell division as well as in flagella and cilia). Another class of proteins involved in movement includes dynein and kinesin, so-called motor proteins that drive the movement of vesicles, granules, and organelles along microtubules serving as established cytoskeletal tracks. ... 

FIGURE 17.23 The mechanism of skeletal muscle contraction. The free energy of ATP hydrolysis drives a conformational change in the myosin head, resulting in net movement of the myosin heads along the actin filament. Inset) A ribbon and space-filling representation of the actin—myosin interaction. (SI myosin image courtesy of Ivan Rayment and Hazel M. Holden, University of Wiseonsin, Madison.)... 

ATP stores in muscle are augmented or supplemented by stores of phosphocreatine. During periods of contraction, phosphocre-atine is hydrolyzed to drive the synthesis of needed ATP in the creatine kinase reaction ... 

Miscibility or compatibility provided by the compatibilizer or TLCP itself can affect the dimensional stability of in situ composites. The feature of ultra-high modulus and low viscosity melt of a nematic liquid crystalline polymer is suitable to induce greater dimensional stability in the composites. For drawn amorphous polymers, if the formed articles are exposed to sufficiently high temperatures, the extended chains are retracted by the entropic driving force of the stretched backbone, similar to the contraction of the stretched rubber network [61,62]. The presence of filler in the extruded articles significantly reduces the total extent of recoil. This can be attributed to the orientation of the fibers in the direction of drawing, which may act as a constraint for a certain amount of polymeric material surrounding them. 

Generally, oxepins have a tendency to contract to a six-membered carbocycle when treated with acid. The driving force is the aromaticity of the phenol formed. However, when the less stable cyclohexa-2,5-diene-1,4-diol with an appropriate substitution pattern is treated with acid, the oxepin system is obtained. The treatment of cyclohexadienediols that are substituted with tert-butyl groups in the 2- and 6-positions and aryl at Cl and C4 with trifluoroacetic acid produces oxepins 1 with elimination of water.186 187 This reaction, however, is restricted to certain aryl substituents with at least some electron-donating effect. Generally, cyclohexa-2,4-dienone derivatives 2 are formed.187,188... 

Muscles only work under contraction owing to the irreversibility of the driving chemical reaction the relaxation of the nervous pulse and the... 

Respiratory drive and rhythm are depressed by barbiturates. Coughing, sneezing, hiccupping, and laryngospasm may occur during anesthesia with barbiturates. Sedative ot hypnotic doses of barbiturates teduce heatt tate and blood pressure to levels found in normal sleep. Anesthetic doses produce more pronounced effects. Barbiturates cross the placenta when used in labor, they can cause respiratoty depression in neonates. Anesthetic doses dectease force and frequency of uterine contractions among pregnant women. 

CHANGES IN THE CONFORMATION OF THE HEAD OF MYOSIN DRIVE MUSCLE CONTRACTION... 

Table 8 5 shows that each of the four common s-block ions is abundant not only in seawater but also in body fluids, where these ions play essential biochemical roles. Sodium is the most abundant cation in fluids that are outside of cells, and proper functioning of body cells requires that sodium concentrations be maintained within a narrow range. One of the main functions of the kidneys is to control the excretion of sodium. Whereas sodium cations are abundant in the fluids outside of cells, potassium cations are the most abundant ions in the fluids inside cells. The difference in ion concentration across cell walls is responsible for the generation of nerve impulses that drive muscle contraction. If the difference in potassium ion concentration across cell walls deteriorates, muscular activity, including the regular muscle contractions of the heart, can be seriously disrupted. 

A further effect during evolution up the AGB is mass loss through stellar winds, at an increasing rate as the star increases in luminosity and radius and becomes unstable to pulsations which drive a super-wind in the case of intermediate-mass stars. For stars with an initial mass below some limit, which may be of order 6 M , the wind evaporates the hydrogen-rich envelope before the CO core has reached the Chandrasekhar limiting mass (see Section 5.4.3), the increase in luminosity ceases and the star contracts at constant luminosity, eventually becoming a white dwarf (Figs. 5.15, 5.19). A computed relation between initial stellar mass and the final white-dwarf mass is shown in Fig. 5.21. 

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