Expenditure of energy

Gas-hquid contac ting systems are utilized for transferring mass, heat, and momentum between the phases, subject to constraints of physical and chemical equihbrium. Process equipment for such systems is designed to achieve the appropriate transfer operations with a minimum expenditure of energy and capital investment. 

Extremely high particulate (coarse and fine) collection efficiencies attainable (at a relatively low expenditure of energy)... 

Energy recovery. Potentially recovers energy through the combustion of waste products, thereby reducing the overall expenditure of energy. 

In thermal fatigue, a ductile fracture usually occurs, characterized by considerable plastic deformation, the tearing of metal, and an appreciable expenditure of energy—as occurs when a strip of metal is repeatedly bent. 

Monomeric actin binds ATP very tightly with an association constant Ka of 1 O M in low ionic strength buffers in the presence of Ca ions. A polymerization cycle involves addition of the ATP-monomer to the polymer end, hydrolysis of ATP on the incorporated subunit, liberation of Pi in solution, and dissociation of the ADP-monomer. Exchange of ATP for bound ADP occurs on the monomer only, and precedes its involvement in another polymerization cycle. Therefore, monomer-polymer exchange reactions are linked to the expenditure of energy exactly one mol of ATP per mol of actin is incorporated into actin filaments. As a result, up to 40% of the ATP consumed in motile cells is used to maintain the dynamic state of actin. Thus, it is important to understand how the free energy of nucleotide hydrolysis is utilized in cytoskeleton assembly. 

A hypothetical separation of a homogeneous mixture, carried out in a thermodynamically reversible manner, would require the theoretical minimum expenditure of energy. In practice, however, separations of such mixtures need 50 to 100 times this minimum. Thus, there is significant opportunity for improvement of separations by creating ways to reduce energy consumption without a commensurate increase in capital and operating costs. 

Tubular reabsorption is considered passive when each of the steps in transepithelial transport takes place without the expenditure of energy. In other words, the movement of a given substance is from an area of high concentration to an area of low concentration by way of passive diffusion. Water is passively reabsorbed from the tubules back into the peritubular capillaries. 

The transport of hydrated sodium and potassium ions through the cell membrane is slow, and this transport requires an expenditure of energy by the cell. 

Penetration. After fusion of viral and host membranes, or uptake into a phagosome, the virus particle is carried into the cytoplasm across the plasma membrane. This penetration process is an active one that requires expenditure of energy by the cell. At this stage the envelope and the capsid are shed, and the viral nucleic acids are released. The uncoating of virus accounts for the drop in infectious virus assayed, because the uncoated virus cannot withstand the assay conditions. 

The quantitative importance of each pathway varies from one tissue to another and from one protein to another. Although hydrolysis of the peptide bonds does not involve ATP, the various processes of protein degradation require considerable expenditure of energy, possibly more than is required for protein synthesis. It is not suprising, therefore, that protein turnover contributes at least 20% to resting energy expenditure (basal metabolic rate). 

This phosphorylation step is achieved by reaction of the 6-hydroxyl with the anhydride ATP, during which process ATP is converted into ADP. This process is driven by the energy contained in the anhydride function of ATP, and represents an expenditure of energy to get the metabolic process started, though... 

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