Operational time factor

Ck - operating time factor for failure k. qk = mean probability of failure k. 

The operating time factor indicates the fraction of the system lifetime or sampling period for which the specifled failure effects are applicable. If the failure mode will always result in the specified effects then this factor should be set to I. If the system operates in different phases, and the effects of failure are only applicable during certain phases then this value should indicate the ratio of applicable phase time lengths to the total lifetime ... 

Factors affecting RO membrane separations and water flux include feed variables such as solute concentration, temperature, pH, and pretreatment requirements membrane variables such as polymer type, module geometry, and module arrangement and process variables such as feed flow rate, operating time and pressure, and water recovery. 

Testing and periodic maintenance can place additional demands on systems, equipment, and components that render them unavailable for service. These details must also be factored into the calculation of operating time for a piece of equipment. 

Using a safety factor of 1 hr, the cementing operation time is obtained from Equation 4-327. This is... 

Determine the cementing operation time and thus the minimum thickening time. Assume a cement mixing rate of 25 sacks/min. Also assume an annular displacement rate no greater than 90 ft/min while the spacer is moving through the open-hole section and a flowrate of 300 gal/min thereafter. A safety factor of 1.0 hr is to be used. 

T]he Origin of Species proposed a radically new idea, conceiving of time not as a power but as a factor whose effect could be perceived directly in distinct but complementary forms fossils, embryos, and rudimentary organs. The fossil was petrified time the embryo, operative time the rudimentary organ, retarded time. Together these bits of evidence constituted the archives of biological history —... 

Movie Operation Time (min) Average Power (W) Power Saving or Lifetime-Enhancing Factor... 

This works out because the ampere (the standard unit of current, abbreviated A) is defined as 1 coulomb per second. Because this equation gives you the amount of charge that has passed through the circuit during its operating time, all that remains is to calculate the number of moles of electrons that make up that amount of charge. For this, you use the conversion factor 1 mol e = 96,500 C. 

Further, economic factors also constrain the utilization of microstructure fabrication technology. These are die factors diat control the cost of production, such as throughput, the rate at which substrates can be processed by the fabrication tools, capital investment required, and demands on operator time and skill. Electron beam exposure, for example, provides high resolution but uses expensive equipment that works slowly. Naturally, all of the elements of cost must be weighed against the value of (lie product produced. 

From a point of view of industrial protein production the number of sequential operations necessary to achieve the desired purity of a protein contributes significantly to the overall costs of the downstream process. This is on one hand due to the capital investment and amount of consumables needed for each step as well as to the individual time requirements of each operation, as labour costs are a very important factor in the calculation of process economics. Secondly the overall yield of the purification is reduced with each additional process step, originating from its inherent loss of product. Furthermore, fast primary recovery should separate the protein of interest from process conditions detrimental to its structural stability, e.g. proteases, glycosidases, or oxidizing conditions. As the performance of the purification process, expressed by its overall yield, operation time, and capital cost may contribute to up to 80% of the total production costs [2], it is evident, that a reduction of the number of sequential steps in a purification protocol may be the key to the economic success of a potential protein product [3],... 

A . Conceivable, sure, but I would rule that out on the basis of time factors. After all, they would have needed corporations again, the SS couldn t do that on their own, even with inmates. Based on the technical requirements for the operation of a gas chamber, which only became known to me later, the building erected by us would have been entirely unsuited for the purpose in regard to the necessary machinery and practicable operation. 

Let us consider some of the special problems encountered in the operation of a radioisotope detector and the compromises that must be considered. Like any chromatographic detector, a carbon-14 detector should have a small volume and a short hold-up time in order to minimize band spreading and loss of resolution. Unfortunately radioisotopes are measured with an inherent time factor - disintegrations per minute. Therefore, the smaller the cell and the shorter the hold-up, the lower will be the sensitivity, a circumstance which is totally at odds with the first requirement. In practice, we have found that a U-tube with a cross-section diameter of 2mm is generally satisfactory. This gives a cell with a void volume of 200-300 yl, which is high compared to the 2-10 yl volumes of many UV flow cells, and may introduce some band spreading when used with the best new HPLC columns. 

As a rule, mathematical models of unsteady-state processes cannot be formulated by simple addition of time derivatives to the equations describing the steady-state behavior of the reaction system. They relate both to the reaction kinetics as well as to the heat and mass transfer processes. For example, modeling of unsteady-state processes in a fixed bed reactor requires accounting for the processes of heat and mass transfer between the catalyst surface and the bulk of gas phase, although for steady-state operation these factors can be neglected. 

As described in Section 1.1, the goal of the simulation study is to quantify the relationships between the simulation outputs and the inputs or factors. For this case study, the outputs are the steady-state mean costs of the whole supply chain (discussed in Section 3.2) and the inputs are factors such as lead-time, quality, operation time of an individual process, and number of resources. Our ultimate goal (as reported by Kleijnen et al., 2003) is to find robust solutions for the supply chain problem. Thus we distinguish between two types of factors ... 

Ever> economic calculation requires the prior determination of an operating cost (FF year) or a cost price (FF/t of product or feed). It also presumes the prior fixing of the stream factor (theoretical operating time of a unit in a year. 8000 h year in general) and the utilization factor, which the ratio of actual output to production capacity (100 per cent in a preliminary calculation). 

FIGURE 8.6 (a) schematic representation of preferential sorption-capillary flow theory (b) critical pore diameter for separation (c) flnx decline with time (d) correction factor for surface area of cellulose acetate and (e) solnte rejection as a function of operating time. 

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