Steady state availability

Chemical considered Media considered Spatial variation Source code availability Model availability Dynamic or steady-state Availability for sensitivity and uncertainty analyses... 

In addition to physically realizable multiple solutions, there are also nonphysical steady states available. These solutions can be problematic, since they usually appear superficially to be valid solutions. In fact, simply by inspection, it is usually impossible to discern if a solution is physical or not. Nonphysical solutions, however, while available and computable in steady state, are unstable in their transient response. That is, a physically valid... 

Sussman, M. V., "Steady-State Availability and the Standard Chemical Availability," Energy (Oxford), 5, 793 (1980). 

In a linear chemical reaction system, there is a unique steady state determined by the chemical constraints that establish the NESS. For nonlinear reactions, however, there can be multiple steady states [6]. A network comprised of many nonlinear reactions can have many steady states consistent with a given set of chemical constraints. This fact leads to the suggestion that a specific stable cellular phenotypic state can result from a specific NESS in which the steady operation of metabolic reactions maintains a balance of cellular components and products with the expenditure of biochemical energy [4]. Similarly, the network of chemical and mechanical signals that regulate the metabolic network must also be in a steady state. Important problems, then, are to determine the variety of steady states available to a system under a given set of chemical constraints and the mechanisms by which cells undergo... 

Availability and reliability are different metrics. Reliability is always a function of failure rates and operating time interval. Availability is a function of failure rates and repair rates. While instantaneous availability will vary during the operating time interval, this is due to changes in failure probabilities and repair situations. Availability is often calculated as an average over a long operating time interval. This is referred to as "steady state availability."... 

In some systems, especially safety instrumented systems, the repair situation is not constant. In safety instrumented systems the situation occurs when failures are discovered and repaired during periodic inspection and test. For these systems, steady state availability is NOT a good measure of system success. Instead, average availability is calculated for the operating time interval between inspections. NOTE - This is not the same measurement as steady state avaUability. 

Problem A controller has a steady state availability of 0.99. What is the steady state unavailability ... 

Steady State Availability— Traditionally, reliability engineers have assumed a constant repair rate. When this is done, probability models can be solved... 

Figure 4-6 shows a Markov probability model of a single component with a single failure mode. This model can be solved for steady state availability and steady state unavailability. 

Given the failure rate of a component and an operational time interval (mission time), one can calculate the reliability of that component. If the component is repairable and the restore rate is estimated, tiie steady state availability of the component can be calculated. If the failure rates, proof test interval, proof test coverage, and component lifetime are known, one can calculate the average probability of fatiure. 

Problem A system consists of three sensors, a controller, a solenoid and an air-operated valve. The system is successful only if all components are successful. The sensors are identical and have steady state availabilities of 0.96. The controller has a steady state availability of 0.999. The solenoid has a steady state availability of 0.9 during its useful life of 5 years. The valve has a steady state availability of 0.9. What is the system steady state availability ... 

Using an average repair rate of 0.333 (1/3 hours), a simple steady state availability equation (Figure G-3) gives an answer of 0.9708. Most would agree that the simple approximation is good enough. 

By resolving the Chapman-Kohnogorov equations at steady state (1), one obtains finally the steady state availability = 0,7895. 

Figure 10 represents results obtained for the average availability under the risky criterion for the transient phase (i.e. starting from the hypothesis that the entire system is up ). The mean values of the steady state availability of Figures 7 and 10 are summarized in Table 3. 

Compliance test procedures for steady-state availability Reliability of systems, equipment and components. Guide to reliability testing. Compliance test plans for success ratio... 

Steady-State Availability (SSA) of a gate is the ratio of mean up time to mean up time plus mean down time over a long, theoretically infinite, period of all basic events. 

Steady state availability of an AND gate, as shown in Figure 2a, having n components with failure... 

Steady state availability of an OR gate, as shown in Figure 2b, having n components with failure rate, ( 1, and repair rate, ) can be given by following mathematical expressions ... 

Thus, the oil and gas industry system time-dependent and steady-state availabilities and unavailabilities, reliability, and mean time to failure are given by Equations 4.11, 4.12, 4.13, 4.14, 4.15, and 4.16,... 

The oil and gas industry equipment steady-state availability and unavailability are given by... 

OGISA is the oil and gas industry system steady-state availability. OGISUA is the oil and gas industry system steady-state unavailability. 

Assume that the constant failure and repair rates of a transportation system are 0.0004 failures/hour and 0.0008 repairs/hour, respectively. Calculate the transportation system steady-state availability and availability during a 10-hour mission. 

Pq/ Pi, and P2 = steady-state probabilities of the vehicle/transit system being in states 0,1, and 2, respectively The vehicle/transit system steady-state availability is given by... 

The vehicle/transit system steady-state availability is given by... 

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