Up-time

Maintenance and operating costs represent the major expenditure late in field life. These costs will be closely related to the number of staff required to run a facility and the amount of hardware they operate to keep production going. The specifications for product quality and plant up-time can also have a significant impact on running costs. 

As ions and neutrals evaporate from a heated filament surface, the amount of sample decreases and the surface densities (C, Cq) must decrease. Therefore, Equation 7.1 covers two effects. The first was discussed above and concerns the changing value for the ratio n+/n° as the temperature of the filament is varied, and the other concerns the change in the total number of ions desorbing as the sample is used up. The two separate effects are shown in Figure 7.8a,b. Combining the two effects (Figure 7.8c) reveals that if the temperature is increased to maintain the flow of ions, which drops naturally as the sample is used up (time), then eventually the flow of ions and neutrals becomes zero whatever the temperature of the filament because the sample has disappeared from the filament surface. 

Load Temperature, °C Holding time. Air removal Heat-up time. Safety Exposure time. 

Great care is needed in the design of autoclaves and sterilization cycles because of the requirement for the presence of moisture. The autoclave must be loaded to allow complete steam penetration to occur in all parts of the load before timing of the sterilization cycle commences. The time required for complete penetration, the so-called heat-up time, varies with different autoclave constmction and different types of loads and packaging materials. The time may not exceed specific limits in order to guarantee reproducibility and, for porous loads, saturated steam. The volume of each container has a considerable effect on the heatup time whenever fluids are sterilized. Thermocouples led into the chamber through a special connector are often employed to determine heatup times and peak temperatures. The pressure is refleved at the end of each sterilization cycle. Either vented containers must be used or... 

ICP-SFMS (Thermo Finnigan, Flement) with cold vapour generation was developed with a guard electrode and a gold amalgamation device using an Au-sorbent for sample pre-concentration to improve the sensitivity. Instrumental parameters of ICP-SFMS such as take-up time, heating temperature of Au-sorbent, additional gas flow, and sample gas flow were optimized. Detection limit calculated as 3 times the standard deviation of 10 blanks was 0,05 ng/1, RSD = 7-9 %. 

Figure 12.34 Fuse selection chart for 6.6 kV system for a motor with run-up time not exceeding 60 seconds...

If oil buffered seals are used on the compressors, the seal leakage toward the process side of the compressor must be carefully measured, as it is (and should be) a small value. While five gallons per day doesn t sound too small, in a four-hour run, this is less than two pints, making the hold-up time at the inner seal chamber and in the lines to the drain pots a significant value. This makes exact measurement quite difficult. 

SPMs are simpler to operate than electron microscopes. Because the instruments can operate under ambient conditions, the set-up time can be a matter of minutes. Sample preparation is minimal. SFM does not require a conducting path, so samples can be mounted with double-stick tape. STM can use a sample holder with conducting clips, similar to that used for SEM. An image can be acquired in less than a minute in fact, movies of ten fiames per second have been demonstrated. ... 

Ease of use 2-6°C storage. Multiple application devices (linear, spray tips, endoscopic, etc.), 20 min preparation time. Set-up time = 30 s-3 min. May wash away in presence of active bleeding. Requires trained personnel to operate equipment. Preparation time required to obtain plasma component. Room temperature storage. 5 min preparation time. Single syringe applicator per kit. Set-up time - 3 min. Effective at site of active bleeding. 

Polymerization to Cg and CJj olefins is the chief side reaction. Polymerization increases with extraction temperature and with the hold-up time in the extraction section. It limits the temperature used to obtain high extraction rates. 

Equation 7-101 ean also he used to ealeulate the heat-up time for non-isothermal heating (e.g., hy hot-water jaeketing), provided that the differenee between the outlet and inlet jaeket temperatures is not greater than 10% of the differenee between the hateh and average water temperature [47]. 

Make PA announcement for personnel to stop hotwork and stay away from MSM PA systems This message takes up time and distracts operator from watching Fire Gas panel. Consider taped messages. 

The failure rates and times-to-restore developed used a variety of data sources and data construction methodologies and are presented in Section 2. The principal methodology used is a kind of failure mode analysis for each component several principle modes of failure are analyed by characteristics including frequency of occurence, repair time, start-up time, and shut-down time. From these an average failure rate is developed and expressed as failures per million hours and mean time between failure(MTBF). 

Figure 13.10 LC-LC chromatogram of a surface water sample spiked at 2 p.g 1 with ati azine, and its metabolites (registered at 220 nm). Conditions volume of sample injected, 2 ml clean-up time, 2.60 min ti ansfer time, 4.2 min The blank was subtracted. Peak identification is as follows 1, DIA 2, HA 3, DEA 4, atrazine. Reprinted from Journal of Chromatography, A 778, F. Hernandez et al, New method for the rapid detemiination of triazine herbicides and some of thek main metabolites in water by using coupled-column liquid cliromatography and large volume injection , pp. 171-181, copyright 1997, with permission from Elsevier Science.

Where these valves are used, the time available to warm up the pipe work will be known, as it is set on the valve control. In other cases, details of the start-up procedure must be known so that the time may be estimated. Thus boilers started from cold may be fired for a short time, shut off for a period while temperatures equalize, and then fired again. Boilers may be protected from undue stress by these short bursts of firing, which extend the warm-up time and reduce the rate at which the condensate in the mains must be discharged at the traps. 

Such fluids often referred to as 5/95 fluid (that being the ratio of oil to water), have essentially the same properties as water with the exception of the corrosion characteristics and the boundary lubrication properties, which are improved by the oil and other additives. The advantages of this type of fluid are fire resistance, lower fluid cost, no warm-up time, lower power consumption and operating temperatures, reduced spoilage of coolant, less dependence on oil together with reduced transport, storage, handling and disposal costs, and environmental benefits. 

A large part of the heating load when operating in daytime will be for fresh or outside air, which is not needed before occupation, and the heat-up time will be reduced if the fresh air supply can remain inoperative for this time. 

The required warm-up time will vary with ambient conditions, being longer in cold weather and least in warm. Optimum-start controllers are now in general use which are programmed for the building warm-up characteristics and sense the inside and ambient conditions. They then transduce the required start-up period and set the heating plant going only when needed. This, and the previous scheme, will save fuel. 

Therrtial Sterilization of Pouches of Beef. Methodology for food thermoprocessing in cylindrical metal containers assured food sterility in flexible packages. Beef slices (1.25 cm thick) were steam cooked to an internal temperature of 72°C and vacuum sealed in pouches to give a fill of 120 g. These pouches of beef were processed in a standard retort with complete water circulation and a superimposed air pressure of 1.7 X 105 Pa. The retort schedule—a 40-minute cook at 118°C plus come-up time followed by a 30-minute cooling time—achieved a F0 (lethality value) of 6. 

Several studies have shown that the shock sensitivity of granular expls depends on expl particle size. The consensus is that the threshold shock pressure to initiate detonation in a given expl is less for large particles than for small particles. However, the converse is true when one considers run-up distances (or run-up times) to detonation. Thus at some pressure above the threshold for both large and small particles, run-up to detonation is smaller for small particle charges than for large particle charges... 

Continuous polymerization processes for PA-6,6 have been reported for over 30 years.5,6,28 Prepolymerization in tubular (Fig. 3.21) or baffled reactors is particularly well suited to continuous polymerization. The polymerization of prepolymers to high-molecular-weight materials in a continuous process is more difficult to control as small differences is molecular weights result in large differences in viscosities. Viscosity differences result in different hold-up times in die reactor and thus nonhomogeneous products. 

For maximum effectiveness the periods of the oscillation were chosen so as to be relatively long with respect to the hold-up time of the reactor (see Figure 1). A control policy was selected so that the following also pertained. 

Discussion. It is apparent from Table II and Figure 3 that even though the reactor has been subjected to very severe oscillatory conditions where the frequency of oscillation was low with respect to the hold-up time and the amplitudes of the functions large, the MWD s of the resulting polymers differ very little from those produced in the steady-flow steady-state. 

The influence of changes in these other variables on MWD in a homopolymerization has not yet been tested, but whatever perturbations are introduced to the feed in a radical polymerization in a laboratory-scale CSTR, they are unlikely to introduce dramatic changes in the MWD of the product because of the extremely short life-time of the active propagating chains in relation to the hold-up time of the reactor. This small change in MWD could be advantageous in a radically initiated copolymerization where perturbations in monomer feeds could give control over polymer compositions independent of the MWD. This postulate is being explored currently. 

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