Periodicity conditions

Where a solid corrosion product is formed, meaningful results are only obtained after a conditioning period for a new measured element. Even so, the conditions under which the scale is laid down may not be the same as that for the original equipment. This objection applies equally to coupons or spools, and points to one of the basic objections of using anything other than the plant itself to monitor corrosion rates. [Pg.31]

In supervisory control, process and economic models of the plant are used to optimize the plant operation by maximizing daily profit, yields, or production rates. The computer program reviews operating conditions periodically, computes the new conditions that optimize a chosen objective function, and adjusts plant controller set points, thus implementing the new improved conditions. This scheme will obviously require a model of the plant, current information about operating conditions from the plant s control system, and finally, sophisticated optimization software. [Pg.265]

R 749 Cyclization agent Reaction tempCC) Conditions period Product Yield %... [Pg.174]

Excreta was collected for two days after treatment. Excreta collected prior to the ten-day conditioning period was also collected and used for the control and DDT experimental tanks. [Pg.185]

Divalent Metal Molybdates. Except for the first point, the conversion of ethane did not change in the conditioning period at 823 K and it lay in the same range as for the N2O as oxidant. The main product was ethylene the selectivity of its foimation mai kedly exceeded that obtained with N2O as oxidant. Acetaldehyde was formed with 4.8% and 6.8% selectivity on the Mg and Zn salts. As a result, the yields for ethylene and acetaldehyde were much higher than in the case of N2O oxidation (Figure 5). Other hydrocarbons and alcohols were also detected in very small concentrations, with less than 1% selectivity. [Pg.375]

The adsorption losses (%) shown in Table VII were used to calculate the amount of solute taken up by a freshly flushed system. Field application of the RO concentration method incorporated conditioning periods in which membranes and other system components were exposed to the sample (and its concentrates) to satisfy and minimize adsorptive solute loss. [Pg.445]

It is generally assumed that humidity is not important in most rubber tests and, hence, conditioning in an atmosphere with control of temperature only is usually specified. However, control of humidity is considered necessary in certain cases, for example testing latex rubber and electrical tests. In many instances the 16h minimum conditioning period will not be sufficient for equilibrium to have been reached, especially with relatively thick test pieces. Hence, all that this conditioning can hope to achieve is to bring test pieces having similar dimensions into more nearly comparable conditions than they would otherwise be. To reach complete moisture equilibrium would in many cases take several days and for thicker test pieces probably weeks. [Pg.54]

Because antiozonants and waxes, which to be effective must form a surface bloom, are used to enhance ozone resistance it is usual to condition test pieces in the strained state before exposure. The usual conditioning period is between 48 and 96h and the test pieces should be kept in the dark and in an ozone-free atmosphere. For this treatment to be effective, the test piece surface must not of course be touched in the course of subsequent handling. Where specifications wish to specifically exclude compounds which rely on an adequate wax film for protection, the conditioning period is dispensed with. Hill and Jowett47 in a criticism of ozone test methods strongly make the point that the conditioning process should be relevant to service conditions if a discriminating evaluation of waxes is to be made. [Pg.333]

After the cell and test piece have been assembled and the high pressure side filled with gas at the test pressure, the increase in pressure on the low pressure side is measured as a function of time. The standard suggests a conditioning period of at least 16 h to reach steady state conditions unless an approximate value of the diffusion coefficient is known, when the minimum conditioning time can be estimated from ... [Pg.352]

Silica-based ether-bonded phases for high-performance hydrophobic interaction chromatography proved stable at pH 6. A column used for a five-month period yielded retention data that within 5 % equaled that from a fresh column immediately after the condition period .This term refers to the first protein injections on a freshly made column with ether-bonded phases, where the protein peak height increases to a constant value with repeated injections56). On a new reversed-phase C 3 column, hydrophobic peptides were much more tenaciously retained than on a repeatedly used one of the same brand. This was observed with columns of 75x4.6 mm do = 30-55 nm dP = 5 pm 69>. [Pg.189]

We consider a vector field v in three-dimensional Euclidean space whose divergence is zero, with boundary conditions periodic in all three coordinates... [Pg.47]

We can define pretreatment as the initial conditioning period whereby a corrosion inhibitor is applied to the metal surfaces of the cooling system. Pretreatment conditions must be conducive to the rapid formation of the protective barrier. The conditioning procedure should involve (1) the cleaning and preparation of metal surfaces, and (2) the actual application of higher than normal inhibitor concentrations. [Pg.189]

Although thermodynamically possible, the slower rate of substitution of the tungsten(VI) species results in the formation of only a small amount of the corresponding thiotungstate ion, provided that the conditioning period with sulfide ion is controlled. Molybdenum trisulfide is then quantitatively precipitated by the decomposition of the thio salt by the slow addition of sulfuric acid to a pH value of between 2 and 3 ... [Pg.828]

After the conditioning period, 500 pL of an aqueous solution of GR-24 (used as internal standard) or the test compounds were added to every Petri dish, sealed with parafilm and incubated for another 4 days in darkness at 20°C. Germination was observed under a microscope (30x) and the germinated seeds expressed as a percentage of the total seeds. Germination was considered when the radicle was at least 0.2 mm long. [Pg.156]

Research discussed in this paper continues our concern with the use of periodic operation to increase catalyst activity. Questions addressed are 1) can periodic operation improve activity in a "hydrogenation" reaction which does not appear to proceed via a redox mechanism 2) will "resonance" effects be observed 3) will non-uniform, but still periodic, concentration square waves be more effective than uniform square waves and 4) will the behavior under periodic operation of a fixed bed reactor with relatively large conversion differ significantly from the behavior in a differential reactor Because hot spot location and magnitude depend on feed conditions, periodic operation should cause the hot spot to wander and should diminish its magnitude. This supposition was examined experimentally in our study. [Pg.98]

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