Motor unit composition

The motor unit has four components a motor neuron in the brain or spinal cord, its axon and related axons that comprise the peripheral nerve, the neuromuscular junction, and all the muscle fibers activated by the neuron. Like other cells, nerve and muscle cells have an external membrane that separates the inner fluids from those on the outside. The fluid on the inside is rich in potassium (K), magnesium (Mg), and phosphorus (P), whereas the fluid on the outside contains sodium (Na), calcium (Ca), and chloride (Cl). When all is quiet, the internal chemical composition of both nerve and muscle cells is remarkably constant and is called resting membrane potential. A primary reason for this constancy lies in the cells ability to regulate the flow of sodium— thanks to an enzyme in the membrane called Na+/K+ ATP-ase. Because the inside of the cell has less sodium than the outside, there is a negative potential (like a microscopic battery) of 70-90 mV. Under ordinary circumstances, the interior of the cell is 30 times richer in potassium than the extracellular fluid and the sodium concentration is 10-12 times greater on the outside of the cell. At rest, sodium tends to flow into cells and potassium oozes out. 

Muscle fibers within a motor unit share common contractile protein composition and metabolic enzyme activities that influence their contractile and fatigue properties (Burke,... 

All rocket motor costs per unit, and therefore rocket proplnt costs, are most sensitive to the number of units being produced and to the number of different formulations mixed in a given time interval, by the same equipment, so that a direct comparson based only on processes or proplnt types are meaningless. There are also inherent difficulties in comparing NC base proplnts with composite propints. The former are made in government plants (some of which are operated by private industry) for the most part and so accounting for indirect costs (taxes, depreciation, insurance, and return on investment) cannot be compared to the situation... 

The demonstrated performance of ZSM-5 in over 35 cracking units is reviewed. The main features of ZSM-5 are its high activity and stability, favorable selectivity, metals tolerance and flexibility, particularly when used as an additive catalyst. ZSM-5 cracks and isomerizes low octane components in the naphtha produced by the faujasite cracking catalyst. As a result and olefins are produced and gasoline compositional changes occur which explain its increased research and motor octanes. A model was developed which predicts ZSM-5 performance in an FCC unit. 

BA-107. Polybutadiene-Acrylic Acid Composite Propellant tot Rocket Motors developed by Thiokol Chemical Corp. Its compn and props are given in conf Propellant Manual ,SPIA/m2 (1959), Unit No 572 B(AM) or BAm(poudre). 

BF.122 BF.I51 are composite polysulfide pro-pints for rocket motors developed by the Thiokol Chem Corp. Their compn props are given in conf Propellant Manual,SPIA/M2( 1959),Unit Nos 570 571... 

The main objective in FCC catalyst design is to prepare cracking catalyst compositions which are active and selective for the conversion of gas-oil into high octane gasoline fraction. From the point of view of the zeolitic component, most of the present advances in octane enhancement have been achieved by introducing low unit cell size ultrastable zeolites (1) and by inclusion of about 1-2 of ZSM-5 zeolite in the final catalyst formulation (2). With these formulations, it is possible to increase the Research Octane Number (RON) of the gasoline, while only a minor increase in the Motor Octane Number (MON) has been obtained. Other materials such as mixed oxides and PILCS (3,4) have been studied as possible components, but there are selectivity limitations which must be overcome. 

For the motor and BTX naphthas from the base crude mix, the preprocessor (1) determines the amount of each component present in the crude, (2) computes the fraction distilled overhead for each component at the naphtha cutpoints specified for the crude distillation unit, (3) constructs for each naphtha the composition of the material remaining between the initial and final boiling points, and (4) computes the blended compositions of the motor and BTX naphthas from the base crude mix. 

The specific impulse (7sp) is the change in the impulse (impulse = mass x velocity or force x time) per mass unit of the propellant. It is an important performance parameter of rocket motors and shows the effective velocity of the combustion gases when leaving the nozzle, and is therefore a measure for the effectiveness of a propellant composition. 

The comprehensive materials and work hours charts (Figs. 19.10 and 19.11) were developed from a theoretical model of a plant with one hundred 460 V motors of different sizes, half of them with interlocks, including allowance for lighting, welding receptacles, 110 V outlets, and grounding, directly proportional to the average hp/motor. The material costs and labor hours are based on the composite unit costs in Table 19.24. 

The unit prices and unit hours represent composites of all materials and operations required for a finished product i.e., the motor hook-up units include the breakers, push button, a pro rata of the MCC cabinet conduits or cable trays, power and control wiring, terminators, miscellaneous supports, unloading and storing materials, testing and commissioning, etc. 

In the 1950 period there was a new area of activity which the explosives industry was called upon to take up. Rocket propulsion had come to stay and the competing merits of liquid and solid systems were to become the center of controversy. While at the time the Hquid fuels like hydrazine seemed to have some advantage, the smaller nonspace rocket motor seems now to be settled in the solids field and an extensive development of solid propellants has taken place. The British (28) invented plastic propellant, a composite of ammonium perchlorate and a polyisobutene binder, while the cast propellant system was developed in the United States together with the curable rubber system. 

The frequency of a noise is analogous to its tonal quality or pitch. The fundamental frequency of middle C on a piano keyboard, for example, is 262 Hz. A tuning fork produces sound at a single frequency, often called a discrete tone. Transformers prodnce sonnd at several discrete freqnencies that are even multiples of hne frequency. In the United States, transformer noise is concentrated at 120,240,360,480, and 600 Hz. However, most sounds include a composite of many frequencies and are characterized as random or broadband. Rotating equipment such as fans and motors usually produces both broadband and discrete tonal noise. 

Wood-plastic composites was bom in Europe and experienced dramatic growth in North America in 1990s. In 1973, a company named SonessonPlast AB (Sweden) promoted a PVCAVF composite product with the trade name Sonwood . This was probably the first commercial WF/PVC composite in the world. Ten years later, in 1983, Woodstock appered in Italy, which consisted of 50 % WF and 50 % PP. WF and PP were extruded into a flat sheet that was then formed into different shapes. It was then applied in interior automotive paneling by Ford Motor Company, becoming the first major applications of WPCs in the United States. 

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