Principle of Operation and Calculations

Did you ever turn a bicycle over on its handle bars, and squirt water from a garden hose at its front wheel What causes the wheel to spin with such great speed What is the property of water, striking the 

It is the velocity of the water, then, that causes the wheel to spin. The velocity of the water is transferred to the spokes of the wheel. 

What force of nature causes a windmill to spin Answer the wind (or the velocity of the air). What causes a steam turbine to spin Answer the velocity of the steam hitting the turbine wheel. 

It is really just like cruise control on your car. You select the speed you want to drive at. If the car is going slower than the speed you selected, or set speed, the gas pedal is depressed, to bring the car up to your selected set speed. The governor speed-control valve is just like the gas pedal. 

The 300-psig steam next passes through the steam nozzle. This is an ordinary nozzle. It screws into a hole in the wall, which separates the steam chest from the turbine case. The nozzle is shaped to efficiently convert the pressure of the 300 psig to steam velocity. The pressure of the steam, as soon as it escapes from the steam nozzle, is already the same as the exhaust steam pressure (100 psig). 

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In ISO standard,the size of sample, having length of 70 mm, width between 6 and 6.4 mm, and thickness between 1 and 5 mm differs from ASTM standard. The equipment, its general principle of operation, and results calculation are essentially similar to the description above for ASTM standard.A special method is developed to describe behavior of plasticized compounds.Plasticized PVC compositions are characteristic in respect to the appearance of curves of the logarithm of the stiffness in torsion as a function of temperature, which have form of reversed S. Three regions were identified in these curves ... 

Electronic ratio controller. In this type of controller, a proportion of both gas and air is diverted through a bypass in which a thermistor sensor measures the flow. The air and gas flows can be compared and the ratio calculated and displayed. A ratio control valve in the air or gas supply, depending on whether the mode of operation is gas- or air-led, will automatically restore a deviation from the pre-set ratio. The electronic controller maintains ratio over a 19 1 turndown. The principle of operation is based on mass flow, so that it can be used with preheated air in recuperative systems. 

Rupture disk, 455 Safety relief valves, 454, 467, 481 Specifications, centrifugal pumps, 209 Spray nozzle particle size, 225 Standards and Codes, 31, 32, 33 Static electricity, 536 Static mixing, 332 Applications, 336 Calculations, 337, 338 Materials of construction, 337 Principles of operation, 335 Type of equipment 334-338... 

Fig. 1.4 Diagram showing the principle of operation of a time-of-flight atom-probe. The tip is mounted on either an internal or an external gimbal system. The tip orientation is adjusted so that atoms of one s choice for chemical analysis will have their images falling into the small probe-hole at the screen assembly. By pulse field evaporating surface atoms, these atoms, in the form of ions, will pass through the probe hole into the flight tube, and be detected by the ion detector. From their times of flight, their mass-to-charge ratios are calculated, and thus their chemical species identified.

Fig. 7.7. The McLeod gauge. The principles of operation follow. Let the unknown pressure in a system be P when the Hg level is below point 1. Let the volume of the bulb and closed capillary above I be V, which is known. When the mercury is allowed to rise past point I, the gas is trapped and finally compressed into the capillary. Suppose that when the mercury in the reference capillary is at 0, the mercury in the dead-ended capillary is B mm below 0 (i.e., the pressure of the compressed gas is B mm). Since the initial pressure-volume product equals the final pressure-volume product, PV = pv, the volume in thecapillary v will be the height B times the area of the capillary bore A. Thus P = pv/V = B (A/V). Since A and V are known and B is measured, the original pressure (P) may be calculated. Most commercial gauges are provided with a calibrated scale which presents pressures directly. Alternatively, it is possible to devise a linear scale for the McLeod gauge, in one such method the mercury height in the closed capillary is always adjusted to the same point (B0), and then the difference in meniscus heights between the two capillaries is measured (AB). For this case the pressure being measured is P = pv0/V = (B0A/V)AB. As in the previous example, the quantity in parentheses represents the gauge calibration constant.

The same principle of operation as described above is applicable also to liquid-liquid extraction where an aqueous liquid and an organic liquid contact each other inside the contactor for extraction of a solute selectively from one phase to another [6-8]. The critical breakthrough pressure for liquid-liquid system could be calculated by Equation 2.1, except that the term A would now be the interfacial tension between the two liquids. Further variation of membrane contacting technology is called gas membrane or gas-gap membrane where two different liquid phases flow on either side of the membrane, but the membrane pores remain gas filled [9-10]. In this situation two separate gas-hquid contact interfaces are supported on each side of a single membrane. 

The principle of operation of a bead mill involves a centrifugal force being transmitted to the grinding beads at the tip of the rotating disc, such that a greater shear force can be applied to the mill base (this explains why smaller, more dense beads are more efficient for grinding). The speed transmitted to the individual chambers of the beads at the tip of the disc assumes that speed and the force can be calculated. 

Its principle of operation is based on Boyle s Law, in that a fixed large volume of the gas at the unknown pressure is compressed to a fixed small volume. The pressure of the gas following compression is measured by a mercury manometer, and the initial pressure is calculated from this pressure and the volume ratio. Pressures as low as 10-6 mm. Hg can be accurately measured by this gage. A major cause for error is the presence of condensable vapors in the gas being measured. Under such conditions the pressure obtained with this gage is closer to the partial pressure of noncondensables than the total pressure. It is not exactly equal to the partial pressure of noncondensables, however, because the condensable vapors may exert a significant vapor pressure after condensation. 

The chemical equilibrium calculations are done by sophisticated computer codes, such as the CONDOR code [2], This code simultaneously considers the dual constraints of mass balance and chemical equilibrium. The operation of the CONDOR code and the general principles of chemical equilibrium calculations are best illustrated using a simplified version of iron chemistry in solar composition material. We define the total elemental abundance of iron as A(Fe). This is the atomic abundance of Fe relative to 106 Si atoms and is 838,000 Fe atoms [5]. The mole fraction (X) of total iron (XFe) in all Fe-bearing compounds is... 

The agreement of measurement and calculation (Eq. (6.13)) is excellent. As expected, decomposition is negligible at the relatively low temperatures of 153 °C for [EMIMJfMeSOj] and 104°C for [EMIM][NTf2], respectively. In principle, the decomposition can also be measured by the MSB, if ambient pressure is used instead of HV [27, 32]. The TGA in a gas overflow is preferable to determine decomposition parameters due to the lower operating expenditures. 

The automatic relative viscometer is ideally suited for measuring dilute polymer viscosities. It provides faster analysis and greater precision than is obtainable with conventional glass tube viscometers (Ubbelohde or Cannon-Fenske), which it replaces. The principle of operation is based on measurement of pressure drops due to the continuous forced flow of solvent and sample through two stainless steel capillary tubes placed in series. The pressure drop across each capillary tube obeys Poiseuille s law. The pressme drop is measured by a differential pressure transducer. The sample solution is loaded into a sample loop via a syringe pump and then pushed into one of the two capillaries. A steady-state condition is reached when the sample solution completely fills capillary 2, solvent remaining in capillary 1 at all times. The relative viscosity of the sample solution is determined simply and directly by the ratio of the pressure drops. From the measured relative viscosity, all other solution viscosity measurements can be calculated. Solution viscosities are determined by the viscosity of the sample relative to the reference solvent. The relative viscometer measures the solvent and sample viscosity simultaneously, so errors due to temperatme fluctuation and solvent variations are avoided. The main advantages of this approach are ... 

We are all familiar with the general principles of operation of an internal combustion reaction the combustion of fuel drives out the piston. It is possible to imagine engines that use reactions other than combustions, and we need to assess the work they can do. A chemical reaction takes place in a container of cross-sectional area 100 cm the container has a piston at one end. As a result of the reaction, the piston is pushed out through 10.0 cm against a constant external pressure of 100 kPa. Calculate the work done by the system. 

Power. There are two main ways to measure the power deUvered by the driver to the pump. The first method is to install a torque meter between the pump and the driver. A torque meter is a rotating bat having a strain gauge to measure shear deformation of a torqued shaft. Discussion of the principle of torque meter operation is available (16). The benefit of this method is direct and accurate measurements. The power deUveted to the pump from the driver is calculated from torque, T, and speed (tpm) in units of brake horsepower, ie, BHP (eq. 4a) when Tis in lbs-ft, and kW (eq. 4b) when T is N-m. 

The design of a plate tower for gas-absorption or gas-stripping operations involves many of the same principles employed in distillation calculations, such as the determination of the number of theoretical plates needed to achieve a specified composition change (see Sec. 13). Distillation differs from gas absorption in that it involves the separation of components based on the distribution of the various substances between a gas phase and a hquid phase when all the components are present in Doth phases. In distillation, the new phase is generated From the original feed mixture by vaporization or condensation of the volatile components, and the separation is achieved by introducing reflux to the top of the tower. 

ISS involves simple principles of classical physics and is one of the simplest spectroscopy for quantitative calculations. Under most standard instrumental operating conditions there is essentially no dependency on the chemical bonding or matrix of the sample. Several workers have discussed quantitative aspects of ISS and ele-ihental relative sensitivities. These have been compiled with comparative measurements of sensitivity obtained from several different laboratories and are shown in... 

Engineering calculations predict emission rates without tlie use of emission factors. These calculations use basic science and engineering principles, chemical property data, and operating conditions to provide a detailed analysis of the emissions for a specific process. Tliis is a more sophisticated approach tluui emission factors, and is useful for evaluating various operational and control alteniatives. 

The principles of strength of materials are applied to the design of structures to assure that the elements of the structures will operate reliably under a known set of loads. Thus the field encompasses both the calculation of the strength and deformation of members and the measurement of the mechanical properties of engineering materials. 

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