Time, elapsed, determination

In a study of tarnishing the parabolic law, Eq. VII-30, is obeyed, with kj = 0. The film thickness y, measured after a given constant elapsed time, is determined in a... 

Sample Transport Transport time, the time elapsed between sample withdrawal from the process and its introduction into the analyzer, shoiild be minimized, particiilarly if the analyzer is an automatic analyzer-controller. Any sample-transport time in the analyzer-controller loop must be treated as equivalent to process dead time in determining conventional feedback controller settings or in evaluating controller performance. Reduction in transport time usually means transporting the sample in the vapor state. 

Smooth starts are possible with steam turbine installations that include an auxiliary boiler because the startup phases of the turbocompressor can be matched to different plant operating conditions. Aside from process-related timing issues, the time elapse or machinery startup duration is generally determined by the temperature gradients admissible on both steam turbine and expander. These factors are influenced by the relative expansion rates of the fixed and rotating components in these machines. 

Cleaning period The total elapsed time that a section of the baghouse is off-stream for cleaning. (This time increment determines the total availability of section fabric for filtration use.)... 

The time elapsed from the ereation of the initial supersaturation to the detee-tion of the first erystals formed in the system is known as the induetion period. The level of supersaturation attained is then akin to the metastable limit . Neither quantity (viz. the induetion time and metastable limit) is therefore a fundamental quantity. Both are useful measures, however, of the propensity of a solution to nueleate. Measurement of the induetion time as a funetion of supersaturation ean be used to help determine erystallization kineties and meehanism. Thus, the induetion time may be expressed by (Walton, 1967)... 

This section deals with the experimental determination of the rate of oil solubilization in aqueous solutions of AOS and IOS [70]. The experimental method [71] consists of injecting 25 pi of n-hexadecane (containing 5 wt % Dobanol 45-3 as an emulsifier) into 50 ml water this produces a turbid macroemulsion upon vigorous stirring. At the start of the experiment, a concentrated solution of the surfactant under test is injected and the decrease in turbidity is followed with a photometer. The time elapsed to reach 90% of the initial turbidity is recorded (t ) and the pseudo rate constant of oil solubilization is calculated from... 

Ra in the water sample and fm is the fraction of the endmember remaining in the sample. Age determinations calculated in such a manner reflect the time elapsed since the water sample became enriched in Ra by the discharge of groundwater. " Ra is regenerated on the order of days. The fraction /em can be estimated either from salinity signal or from the distribution of isotopes, but this term can be difficult to... 

From a practical perspective, determining the time elapsed since the solid was at high temperature by thermoluminescence or optically simulated luminescence requires four successive stages ... 

Periodic ( e1w ) and aperiodic (e.g., e processes in nature can be used for dating. For the following we mainly concentrate on aperiodic processes, changing the state of a system in nature as well-known functions of time. The present (or end) state of the system is experimentally determined and the initial state of the system is estimated. The time function for system changes then enables us to calculate the age, i.e., the time elapsed between the initial and final states. 

Again we use expression (26.12) and (26.13) to determine the time elapsed. The initial rate of decay is about 15 dis/min. First we compute the decay constant. 

But how, having defined the half-life h/2 as the time necessary for half of a substance to decay or disappear, can we quantitatively determine the time elapsing since Otzi died In Justification Box 8.4, we show how the half-life and the rate constant of decay k are related according to... 

The simplest measurement of the response time of macroelectrodes involves the determination of the time elapsed from the transfer of the ISE from the solution in which it was stored into the test solution. Data obtained in this way are only significant for response times of at least tens of seconds. For short response times, flow-through [44, 131] or injection [92] methods are suitable. For microelectrodes, a rapid immersion method [181], a flow-through [166] or an iontophoretic method [97] have given good results. In the last method... 

In an effort to improve the accuracy of the determination of the end-point, the triangle-programmed titration was devised [97]. The sample with concentration Cx flows at a constant rate of Wj. The titrant is introduced at programmed volume flow-rate Ir, the change in Fr following the pattern of an isosceles triangle (fig. 5.13a). The time of the whole program is 2t, for tr, Ir =(2r—r)n n and t are constants. The maximum titrant mass flow should exceed the sample mass flow (= c w ). Two connected titration curves are obtained (fig. 5.13h), the time elapsed between the two equivalence points for the titration reaction... 

Typically, a catalyst becomes synthetically nsefnl when. k> 10. Indeed, with such levels of selectivity one can isolate a synthetically nsable amonnt of essentially enan-tiomerically pnre nnreacted starting material by driving the reaction past 50% conversion. With a process of high selectivity (e.g.,. y > 50), significant amonnts of highly enantio-merically enriched both nnreacted starting material and prodnct can be isolated at close to 50% conversion. Unfortunately, the selectivity factor is not directly measurable [11]. Its determination is based on measnrements of parameters snch as the conversion (C), the enantiomeric composition of the snbstrate and prodnct (enantiomeric excess, ee, or preferably [12], enantiomeric ratio, er) and the time elapsed (t) [13]. Its determination is also prone to error [14], notably if the enantiomeric pnrity of the catalyst is not absolnte [15-18]. Despite these limitations in this review we have tried to record. y and C valnes as well as eekr values where available. 

Ignition Delay. If the igniter is of the delay type, it is necessary to determine the time elapsed from the start of current flow to the rupture of the igniter case. For instance, the M12 electric igniter has an ignition delay not exceeding 100 milliseconds (Ref 2)... 

Find the distance the boat has moved and use it to complete the right triangle. The hypotenuse is the length of the rope. Divide the length of the rope by the time elapsed to determine the average rate at which the rope is playing out. 

With a molecular emission cavity flame detector, relying on measurement of the 526 nm emission of HPO (see Section II.C.l and III.B.3.b), nanogram amounts of phosphates or organophosphorus compounds can be assessed in automated systems160,348. Determination of m, the time elapsed between sample ignition and maximum emission, allows the resolution of ternary or more complex mixtures of insecticides. Dicrotophos, dimethoate, malathion and parathion mixed in aqueous solution were separated and identified in nanograms per millilitre concentrations348. 

The specific activities of radionuclides in samples from surface burst debris are not necessarily unique functions of the particle size. The uniqueness is determined by the degree of mixing in the cloud, and is, therefore, expected to be a function of the time elapsed between the shot time and the sampling time. 

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