Flow rate and pressure

The relative abundance of neutral SiH and H2 species have been measured as a function of power, pressure, flow rate, and dilution. For low power levels, eg, 5 W, up to 50% of the SiH gas is dissociated and the percentage increases to 80% for a power of 50 W. The decomposition of SiH gas proceeds more readily with lower flow rates. These observations, coupled with infrared (ir) measurements performed on the films, suggest that deposition under conditions in which the silane gas is not entirely decomposed leads to a majority of SiH units, whereas those deposited under conditions in which silane is strongly dissociated contain a majority of dihydride units leading to a deterioration of the semiconductor. Also, when the dwell time of SiH in the plasma region increases, the resultant film exhibits a pronounced peak at 2090 cm from the ir spectra corresponding to S1H2 inclusion. 

Another instance in which the constant-temperature method is used involves the direc t application of experimental KcO values obtained at the desired conditions of inlet temperatures, operating pressure, flow rates, and feed-stream compositions. The assumption here is that, regardless of any temperature profiles that may exist within the actu tower, the procedure of working the problem in reverse will yield a correct result. One should be cautious about extrapolating such data veiy far from the original basis and be carebil to use compatible equilibrium data. 

Temperature, pressure, flow rate, and ozone concentration of the ozonecontaining gas being discharged from all the ozone generators. This is the only effective method by which ozone dosage and the ozone production capacity of the ozone generator can be determined. 

Air terminal units (ATUs), item at the end of a duct run to control velocity, pressure, flow rate, and/or temperature,... 

Tlic heat duty is best calculated with a process simulation program hi will account for phase changes as the fluid passes throiigli ilic ctioke. It will balance the enthalpies and accurately predict the change m tcnipcrature across the choke. Heat duty should be checked for vanoits combinations of inlet temperature, pressure, flow rate, and outlet temper ature and pressure, so as to determine the most critical combination. 

The heat duty may have to be checked for various combinations of inlet temperature and pressure, flow rate, and outlet temperature and pressure to determine the most critical combinations. 

Kubaschewski and Hopkins consider the conditions of the gaseous phase which influence the rate of corrosion of metals apart from major variations of composition, they refer also to the effects of minor impurities, gas pressure, flow rate and ionisation. 

Sampling points for analysis should be planned in order to give the whole record of analysis, e.g. in oil production from the well via processing facilities to the export facilities. Correlation with plant parameters such as temperatures, pressures, flow rates and, stream compositions can provide valuable records. Emphasis on chemical analysis should be incorporated in the design of process plant. Automatic analysis systems especially those using ion-sensitive electrodes with recording of data are recommended. 

In the formulation of Bickel et al. (B7) which appears to be the most general formulation on this problem to date, both the feed and delivery conditions (temperature, pressure, flow rate, and composition) are specified. As before, the decision variables include the pipe diameters. But in addition, the number, placement, suction, and delivery pressures of compressors may also be varied within the constraints of overall pipeline lengths and network... 

Flow rate and extraction time. Decreasing solvent flow rate results in an increased of extraction yield using SC-CO2. The extraction time is a function of the matrix structure, differing with the type of material. For example, diffusion through a nut is faster than that through a seed. Time is inversely related to the particle size, and many other process parameters can influence this variable, such as temperature, pressure, flow rate, and cosolvent addition (Saldana 1997 Saldana and others 2002a,b Mohamed and others 2002). 

Monitoring, Collection and manipulation of data for control and diagnostic purposes. Monitoring systems will have sensors to measure temperatures, pressures, flow rates, and the... 

The membrane performance for separations is characterized by the flux of a feed component across the membrane. This flux can be expressed as a quantity called the permeability (P), which is a pressure- and thickness-normalized flux of a given component. The separation of a feed mixture is achieved by a membrane material that permits a faster permeation rate for one component (i.e., higher permeability) over that of another component. The efficiency of the membrane in enriching a component over another component in the permeate stream can be expressed as a quantity called selectivity or separation factor. Selectivity (0 can be defined as the ratio of the permeabilities of the feed components across the membrane (i.e., a/b = Ta/Tb, where A and B are the two components). The permeability and selectivity of a membrane are material properties of the membrane material itself, and thus these properties are ideally constant with feed pressure, flow rate and other process conditions. However, permeability and selectivity are both temperature-dependent... 

Instrumentation for measuring and controlling the temperature, pressure, flow rates, and fluid compositions, including oxygen partial pressure, is necessary for fermentor operation. (Details of instrumentation and control for fermentation are provided in Chapter 13.)... 

However, the actual combustion process takes place by a manifold of hundreds of elementary reactions. Thus the kinetics exhibit complex behavior as a function of temperature, pressure, flow rates, and so on. 

The progress of a given reaction depends on the temperature, pressure, flow rates, and residence times. Usually these variables are controlled directly, but since the major feature of a chemical reaction is composition change, the analysis of composition and the resetting of the other variables by its means is an often used means of control. The possible occurrence of multiple steady states and the onset of instabilities also are factors in deciding on the nature and precision of a control system. 

Tests must be performed to ensure that the pump is working well pressure, flow rate, and gradient linearity. 

Table IV. Temperature, Pressure, Flow Rate, and Mole Fraction of Different Numbered Streams in the Flow Diagram...

The selection of the technology of compact heat exchangers depends on the operating conditions, such as pressure, flow rates, and temperature, as well as on other parameters, such as fouling, corrosion, compactness, weight, maintenance, and reliability. Table 1 summarizes the major limits for the different types of compact heat exchangers. 

The sample is loaded into an extraction cell and placed into the heating oven. The temperature, pressure, flow rate, and the extraction time are set, and the extraction is started. The extract is collected either by a sorbent trap, or by a collection vial containng a solvent. Typical EPA-recommended operating conditions for the extraction of PAHs, pesticides, and PCBs are... 

The dependence of the etching selectivity of X-8000K2 relative to PIQ (a polyimide type resin from Hitachi Chemical Co.,) on O2 RIE conditions was examined. RIE power, O2 pressure, flow rate and the distance between the electrodes were selected as the parameters to determine the RIE condition. For these parameters, values of 100 W, 10 m Torr, 10 SCCM and 6 cm were selected as a standard condition. The changes in the etching rates are shown in Figure 3a, in which one parameter is varied and the remaining three parameters are fixed. 

Automatic valves are part of a control loop, which is shown in Figure 8.6. The loop contains a primary element, which measures the controlled variable, such as temperature, pressure, flow rate, and liquid level. The operation of a control loop is the same regardless of what variable is controlled. In the case of flow-rate control, the controller obtains the flow rate from transmitter a flow meter and compares the measured flow rate with a value that has been preset in the controller. If the flow rate is greater than the preset value, the controller increases air pressure on top or bottom of a diaphragm in the valve. Then, the valve partially closes to reduce the flow rate. On the other hand, if the flow rate is below the preset value, the controller will act to reduce the air pressure on the diaphragm, and hence the valve opens wider. Electric motors can also operate automatic control valves. 

Chemical vapor deposition (CVD) is an atomistic surface modification process where a thin solid coating is deposited on an underlying heated substrate via a chemical reaction from the vapor or gas phase. The occurrence of this chemical reaction is an essential characteristic of the CVD method. The chemical reaction is generally activated thermally by resistance heat, RF, plasma and laser. Furthermore, the effects of the process variables such as temperature, pressure, flow rates, and input concentrations on these reactions must be understood. With proper selection of process parameters, the coating structure/properties such as hardness, toughness, elastic modulus, adhesion, thermal shock resistance and corrosion, wear and oxidation resistance can be controlled or tailored for a variety of applications. The optimum experimental parameters and the level to which... 

After the SCF system was operational, it was necessary to determine process parameters for removal of the common contaminants. Temperature, pressure, flow rate and time were identified as critical parameters and a number of experiments were designed using Taguchi methods to minimize the number of experiments necessary to accurately determine the effects of these parameters on the cleaning effectiveness. Damping fluid, Krytox 143AZ lubricant, and hydrocarbon vacuum pump oil were selected as the contaminants for removal. 

Begin by filling in all known quantities in the appropriate location in the table, and put dashes (—) in every cell of a stream column corresponding to species not present in that stream. Thereafter, whenever you determine the temperature, pressure, flow rate, and/or composition of a process stream, calculate and enter the corresponding values in the table. When you have worked through the entire case study, every cell should contain either a dash or a number. When doing mass/mole conversions, use 35.45 as the atomic weight of chlorine. 

In case of complex membrane morphology such as asymmetric or composite membranes, or when Fickian diffusion is not valid, evaluating will be more complex. Individual mass transfer coefficients in Equation 2.2 depend on multiple factors such as temperarnre, pressure, flow rates, and diffusion coefficients and could often be estimated from empirical correlations available in literature [1,2,6]. 

The objective of the experiments carried out in this pilot plant was to determine the optimal values of some operational parameters, such as biomass concentration, transmembrane pressure, flow rate, and hydrauhc retention time, the last defined as the relationship between the volume of the bioreactor and the daily flow discharge of permeate. The working plan was as follows ... 

To specify the feed, we must enter the temperature, pressure, flow rate, and composition. The temperature, pressure, and flow rate are entered in the stream editor window, as illustrated in Figure 4.6. The feed composition can be entered as 100% of any of the G5 paraffin species, for example, normal pentane. The results from a Gibbs reactor would be the same if 100% isopentane were entered. It should be noted, however, that if a mixture of a pentane and a pentene were specified, then the overall ratio of hydrogen to carbon would be different and different results would be obtained. 

Before installing a membrane operation system, membrane testing is required to determine the capability of the particular polymer for the separation, optimum membrane configuration in the application, and optimum processing conditions (e.g., pressure, flow rates, and temperature). 

In addition to its high dissolution efficiency, another powerful aspect to SFE is its ability to precisely control which component(s) of a complex matrix are extracted and which ones are left behind. This is accomplished through precise control of several key operating parameters such as temperature, pressure, flow rates, and processing time. Yields are much greater with SFE than extractions performed by traditional techniques, and product purity is usually high. Decomposition of materials almost never occurs due to the relatively mild processing temperatures. 

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