Micro-indicators

Microfluidics is about the flow of tiny amounts of liquids. The prefix micro indicates that at least in two dimensions, the liquid should be confined in micrometer dimensions. If we are, for instance, dealing with a channel, its width or diameter should be below 100 /tm to earn the title microchannel . Please note that a microliter is a relatively large volume in microfluidics since it is equal to the volume of (1 mm)3. 

C For A, the prefix micro— indicates 10-6. 32 micrograms is 0.000032 g. For B, the two measurements do not have the same meaning because they differ in the number of significant figures. 26 nm is 2.6x10-8 m. The symbol "n" for nano— indicates 10-9. For C and D, unit conversions between cubic meters and liters are required. 

The American Chemical Society has long occupied a central position within the institution of chemistry. The choice of a president for the Society symbolizes the institution s values. The careers of presidents display something of the changing nexus between occupation, profession and discipline. Those values and that nexus may be partially exposed by a highly disaggregated analysis using what might be termed micro-indicators . In this last section we shall turn away from macro-indicators of the institution of chemistry and instead use micro-indicators to elucidate certain matters of interest. The use of micro-indicators also provides a specimen of the possibilities inherent in the analysis of fine structure, an effort which may be mounted within the frame secured by macro-indicators of the kind presented earlier in this work. ... 

These examples suggest some of the ways in which it is possible to move between macro- and micro-indicators, and from the latter to familiar levels of historical analysis. Our report has necessarily focused on macro-indicators in an endeavor to assay the changing structure of American chemistry over a century-long period. The assembling of those indicators is one move toward the creation of a context in which more fruitful historical and policy questions may be posed. Many of those questions hinge on a detailed knowledge of the fine structure of events, of a kind that depends on the availability of many micro-indicators. 

When the correct solvent for recrystallisation is not known a procedure similar to that given on pp. 15-16 should be followed, but on the semi-micro scale not more than 10 mg. of the solid should be placed in the tapered-end test-tube (Fig. 29(B)) and about o i ml. of the solvent should be added from the calibrated dropping-pipette (Fig. 30(B)). If the compound dissolves readily in the cold, the solvent is unsuitable, but the solution should not be discarded. [In this case recourse should be had to the use of mixed solvents (p. 18). For example if the substance is very soluble in ethanol, water should be added from a calibrated pipette with shaking to determine whether crystallisation will now take place, indicated by a cloudiness or by the separation of solid.]... 

It was found that sorbed palladium might catalyse reaction of Mn(III) reduction by Cf not only after it s removing from coal, but AC with palladium, Pd/AC, has also his own catalytic effect. On the base of dependence between characteristics of AC, chemical state of palladium on AC surface and catalytic action of Pd/AC in indicator reaction it might establish, that catalytic action concerns only to non-reduced or partly reduced palladium ions connected with chloride ions on coal surface. The presence or absence of catalytic action of Pd/AC in above-mentioned reaction may be proposed for determination of chemical state of palladium on AC surface. Catalytic effect was also used for palladium micro-amounts determination by soi ption-catalytic method. 

Because C-curves are determined by quench-hold-quench sequences they can, strictly speaking, only be used to predict the micro structures that would be produced in a steel subjected to a quench-hold-quench heat treatment. But the curves do give a pretty good indication of the structures to expect in a steel that has been cooled eontinuously. For really accurate predictions, however, eontinuous eooling diagrams are available (see the literature of the major steel manufacturers). 

Most of the optical-alignment systems incorporate a micro-processing unit, which eliminates recording errors commonly found with reverse-dial indicator and rim-and-face methods. Optical systems automatically maintain the proper orientation and provide accurate offset and angularity data, virtually eliminating operator error. 

The Micro-method uses an analytical instrument to measure Conradson carbon in a small automated set. The Micro-method (ASTM D4530) gives test results that are equivalent to the Conradson carbon residue test (D189). The purpose of this test is to provide some indication of relative coke forming tendency of such mat al. 

The first step in E-cat testing is to bum the carbon off the sample. The sample is then placed in a MAT unit (Figure 3-13), the heart of which is a fixed bed reactor. A certain amount of a standard gas oil feedstock is injected into the hot bed of catalyst. The activity i.s reported as the conversion to 430°F (221°C) material. The feedstock s quality, reactor temperature, catalyst-to-oil ratio, and space velocity are four variables affecting MAT results. Each catalyst vendor uses slightly different operating variables to conduct micro activity testing, as indicated in Table 3-2. 

The underlying theory may be simplified as follows. Polarography is concerned with electrode reactions at the indicator or micro-electrode, i.e. with reactions involving a transfer of electrons between the electrode and the components of the solution. These components are called oxidants when they can accept electrons, and reductants when they can lose electrons. The electrode is a cathode when a reduction can take place at its surface, and an anode when oxidation occurs at its surface. During the reduction of an oxidant at the cathode, electrons leave the electrode with the formation of an equivalent amount of the reductant in solution ... 

The influence of pH on the affinity of Hb for oxygen known as the Bohr-effect indicates that protons retain the allosteric regulation of oxygen transport. It is also an indirect confirmation of the ability of Hb and Im Hb for transporting carbon dioxide. The values of the Bohr-effect d log P50/d pH for Hb and Im Hb are close to each other in the pH range 7.1-7.4. It is possible that the effect of the micro-environment of carboxylic CP on immobilized Hb and its polyfunctional interaction represents the interaction between Hb and the structural elements inside the red cell [99]. 

The particle-size distribution of two test powders, spherical glass beads and crushed quartz was determined with different types of app (Ref 32), and indicate that the micro-mesh sieve data is in good agreement with those of other methods (Table 6) ... 

The heat transfer correlations are considered separately in the laminar and turbulent regimes in Figs. 2.21 and 2.22, respectively. The dependence of the Nusselt number on the Reynolds number is stronger in all the micro-channel predictions compared to conventional results, as indicated by the steeper slopes of the former Choi et al. (1991) predict the strongest variation of Nusselt number with Re. The predictions for all cases by Peng et al. (1996) also fall below those for a conventional channel. 

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