Liquid resistance

The electrolytes are non-corrosive and the electrodes do not corrode with time. This feature is of special significance when compared with an ordinary liquid resistance starter used commonly for slip-ring motors. Electrolytes do not deteriorate and therefore do not require replacement. The evaporated liquid can be replenished with drinking water when the level of the electrolyte falls as a result of evaporation. In Europe such starters have been used for over 15-20 years. Electrolyte switching is a costlier proposition compared to direct on-line or star/delta switching due to additional shorting contactor and timer, and the cost of electrolyte, its tank and thermostatic control etc. The cost may. 

Byatt. J.R., Selection of Primary Starters for Cage Motors and Secondary Starters for Slip-ring Motors, AOIP Electrical, UK. Kajiji, Y.H., Liquid Resistance Starting, AOYP Engineering Co. (P) Ltd, Mumbai, India. 

Industrial finishing systems are applied to a wide variety of substrates, the majority of which are metallic, but they are also applied to paper, wood, wood composites, cement products and plastics. Often a high quality of decoration is required, as well as protection from a number of hazards, such as knocks, abrasions, bending or forming and contact with non-corrosive liquids. Resistance to the weather may be required. Outdoor finishing systems, and many others, are also required to protect metal against corrosion. 

Increase in mass-transfer rate per unit area. As stated above, agitated gas-liquid contactors are used, in general, when it is necessary to deal with sparingly soluble gases. According to the terminology of the film theory, absorption is then controlled by the liquid resistance, and agitation of the liquid phase could increase the mass-transfer rate per unit area. As will be... 

Manufacture of Printed Wiring Boards. Printed wiring boards, or printed circuit boards, are usually thin flat panels than contain one or multiple layers of thin copper patterns that interconnect the various electronic components (e.g. integrated circuit chips, connectors, resistors) that are attached to the boards. These panels are present in almost every consumer electronic product and automobile sold today. The various photopolymer products used to manufacture the printed wiring boards include film resists, electroless plating resists (23), liquid resists, electrodeposited resists (24), solder masks (25), laser exposed photoresists (26), flexible photoimageable permanent coatings (27) and polyimide interlayer insulator films (28). Another new use of photopolymer chemistry is the selective formation of conductive patterns in polymers (29). 

Liquid propellants, 10 726 Liquid propylene, compressed, 20 770 Liquid pyridine, 21 93 Liquid range, of ionic liquids, 26 848-851 Liquid resins, viscosities of, 10 385 Liquid-resist interface, 15 187 Liquid resole resins, in air and oil filters, 18 790... 

The coalesced oil droplets rise countercurrent to the downflowing water in the housing When the oil in the top ol the housing reaches a given volume, an electronic probe senses a change in liquid resistivity and an automatic oil removal valve is opened The recovered oil is reported to be water-free. 

The same occurs with the stirring speed. A gas-starved condition can be achieved by a very low stirring speed. This may be desirable in some hydrogenations where it is necessary not to allow too much hydrogen to be transferred into the liquid (for selectivity reasons). Then, if stirring is increased, the reaction rate increases up to a point where it does not increase further. Since the gas/liquid resistance has already been lowered, the reaction rate becomes the maximum possible. 

Hydrogenations were also carried out in 100% ethyl pyruvate and the results are shown in Figure 8. It should be noted that the turnover frequencies are lower than those observed in toluene (compare Fig. 7. with Fig. 8.). But more importantly, both TOF and ee s increase with particle size Gas-liquid resistance can be excluded since KLa for H2 transfer into ethyl pyruvate has been measured and is also about 0.06 s 1 at 600 RPM. Further, intraparticle control is unlikely because the TOF s should decrease with panicle size. Hence, we think that these observations can be explained by liquid-solid mass transpon effects as follows. The apparent density of the catalyst... 

If even larger particles are considered, repeating the above calculation shows that, although the gas-liquid resistance (a) decreases, both the liquid-solid resistance (b) and the reaction term (c) increase. As a result of these opposing tendencies, there must exist an optimum particle size for which the overall resistance is a minimum and therefore the overall reaction rate is a maximum. More detailed calculations 363 show that for the value of the rate constant k = 16.8 s 1 used above, the optimum particle size is indeed approximately 2 mm which is the size taken for the example. However, for lower values of the rate constant, the optimum shifts towards smaller particle sizes, the reason being that the gas-liquid interfacial area for mass transfer becomes less important. 

As PWB technology is refined to provide greater integration using finer conductor lines, there is renewed interest in liquid resists. The absence of a cover sheet and the ability to apply thinner films both contribute to improved resolution and to an intrinsically lower consumables cost (16,17). 

The dry Murphree efficiency calculated thus far takes into account the vapor and liquid resistances and the vapor-liquid contact patterns, but is uncorrected for the effects of entrainment and weeping. This correction converts the dry efficiency to a "wet or actual Murphree tray efficiency. Colburn [Eq. (14-98), under "Entrainment ] incorporated the effect of entrainment on efficiency, assuming perfect mixing of liquid on the tray. 

Mechanical properties (stiffness, impact, and shock resistance), electrical properties, clarity, ease of processing, sealing properties, dimensional stability, resistance to hydrocarbons and other organic liquids, resistance to plasticizers, greases, and oils are the characteristic properties desired. In its mechanical properties it approaches polycarbonate most closely. However, since polycarbonate is cheaper than Trogamid T, Trogamid T will be preferred only where polycarbonate cannot be used. 

Experiments of physical absorption of C02 diluted with N2 into pure water allow to measure gas side mass transfer coefficients. In this case, we measure the total mass transfer resistance (liquid+gas), using the method for the kLa determination ( 3.1). Knowing the liquid resistance, we can then calculate the gas side one. The pressure of interest in this case is the partial pressure of C02, which is obtained by simultaneous measurements of total pressure and molar fraction of C02 versus time. 

LIQUID RESISTANCE TO INTERPHASE MASS TRANSFER. Liquid viscosity, gas solubility in absorbers, and relative volatility in rectification columns are important factors in determining the liquid resistance to interphase mass transfer. Increase in liquid viscosity, decrease in gas solubility for absorbers, and increase in relative volatility for rectification columns cause an increase in the liquid resistance to interphase mass transfer and a resultant reduction in plate efficiency. The ratio of the liquid rate to the gas rate influences the relative importance of the liquid resistance to interphase mass transfer. An increase in the ratio of liquid rate to gas rate reduces the importance of the liquid resistance and can cause an increase in the plate efficiency. 

For dilute systems, the height of a transfer unit for the gas resistance Hg and that for the liquid resistance Hi are related to their respective mass transfer coefficients by... 

Calculate the height of packing required. Based on individual liquid-transfer units, Z = HiNi = (3.48 ft)(13.32) = 46.3 ft. Based on overall liquid transfer units, Z = H0iN0i. The height of an overall transfer unit based on the liquid resistance is calculated as follows ... 

Related Calculation. When the equilibrium and/or operating lines are curved, Eqs. (11.27) and (11.28) do not apply exactly. In this case, it is necessary to base the design on the individual number of transfer units for the liquid resistance and integrate graphically to determine Nt. This is illustrated in the following example. 

For the type spray-charging device described, pesticide-liquid resistivity is generally limited to the fairly narrow 10 - 10 ohm m region of values. 

Fig. 5 SEM micrograph of an imprinted high-aspect ratio grating pattern with a 250 nm line width, and a 1.8 gm height using PDMS-based thermal curable liquid resist.

This value is threefold that of the observed (global) rate. Decreasing the bubble size would be a step in this direction. Increasing the hydrogen-flow rate at constant bubble size would have the same effect, since this would increase gas volume and Qg. Better agitation would also reduce the bubble-to-liquid resistance, as demonstrated in Example 10-5. 

For distillations, the vapor resistance dominates, whereas for the stripping or absorption of slightly soluble materials, the liquid resistance dominates. In Equation (12.75), m is related to the VLE ratio [Equation (12.19)], and for the binary distillation of an i-j mixture is defined as the slope of the equilibrium line on a y-x diagram ... 

The relative importance of the gas and liquid resistances can be estimated by assuming that the penetration theory applies to both phases and with the same contact time. Since the penetration theory [Eq. (21.44)] gives k, and and equal k p y and Kpmx> respectively,... 

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