Reservoir through-flow

Another development arising from FAB has been its transformation from a static to a dynamic technique, with a continuous flow of a solution traveling from a reservoir through a capillary to the probe tip. Samples are injected either directly or through a liquid chromatography (LC) column. The technique is known as dynamic or continuous flow FAB/LSIMS and provides a convenient direct LC/MS coupling for the on-line analysis of mixtures (Figure 40.2). 

Air is fed from a reservoir through a converging nozzle into a 1 /2 in. ID drawn steel tube that is 15 ft long. The flow in the tube is adiabatic, and the reservoir temperature and pressure are 70°F and lOOpsia. 

Examine the HPLC instrument to which you are assigned. Find the inlet line to the pump and place the free end of this line in the reservoir containing the mobile phase with the 90/10 composition. Trace the path of the mobile phase from the reservoir, through the pump, injection valve, column, and detector, to the waste container so that you identify and recognize all components of the flow path. Turn on the pump and detector and begin pumping the mobile phase at a rate... 

Batch flow times are generally used in other words, the time required for a fixed amount of sample to flow from a reservoir through a capillary is the datum actually observed. Any features of technique that contribute to longer flow times are usually desirable. Some of the principal capillary viscometers in use are those of Cannon-Fenske, Ubbelohde, Fitzsimmons, and Zeitfuchs. 

The surface molecules are under a different force field from the molecules in the bulk phase or the gas phase. These forces are called surface forces. A liquid surface behaves like a stretched elastic membrane in that it tends to contract. This action arises from the observation that, when one empties a beaker with a liquid, the liquid breaks up into spherical drops. This phenomenon indicates that drops are being created under some forces that must be present at the surface of the newly formed interface. These surface forces become even more important when a liquid is in contact with a solid (such as ground-water oil reservoir). The flow of liquid (e.g., water or oil) through small pores underground is mainly governed by capillary forces. Capillary forces are found to play a very dominant role in many systems, which will be described later. Thus, the interaction between liquid and any solid will form curved surface that, being different from a planar fluid surface, initiates the capillary forces. 

Non-local mass exchange The effective mass flow is non-local (Case A) when atoms at a step edge can directly exchange with a vapor reservoir (through evaporation-condensation) or with an overall terrace reservoir that forms by fast direct adatom hops between different terraces. In such cases, we assume that step velocity is proportional to the chemical potential difference between the step and the reservoir ... 

Air, at a pressure of 10 MN/m2 and a temperature of 290 K, flows from a reservoir through a mild steel pipe of 10 mm diameter and 30 m long into a second reservoir at a pressure P2. Plot the mass rate of flow of the air as a function of the pressure P2. Neglect any effects attributable to differences in level and assume an adiabatic expansion of the air. ji = 0.018 rnN s/m2, y = 1.36. 

The reactor was stirred at 1600 RFM, Intimately mixing the acid and hydrocarbon phases. Contact times (half the reactor volume divided by the hydrocarbon feed rate) ranged from 0.3 to 3.0 minutes. The temperature Inside the reactor was controlled by passing water or antifreeze solution from a controlled temperature reservoir through the jacket of the autoclave. The reaction temperature was monitored by a sheathed thermocouple Inserted Into the autoclave just below the stirrer. A stream of acid-hydrocarbon emulsion passed continuously from the autoclave to the settler. The acid catalyst settled to the bottom and returned to the reactor by gravity flow. The hydrocarbon product passed out the top of the settler through a pressure control valve which maintained the reactor at 200 pslg. 

The general arrangement of an hplc system is fairly simple, as shown in Fig. 9.17. Solvent is pumped from a reservoir through a piston pump which controls the flow rate. From the pump the solvent passes through a pulse damper which removes some of the pulsing effect generated in the pump and also acts as a pressure regulator. In between the pulse damper and the column there is an injection valve which allows the sample to be introduced into the solvent stream. 

Water flows from an elevated reservoir through a conduit to a turbine at a lower level and out of the turbine through a similar conduit. At a point 100 m above the turbine the pressure is 207 kPa, and at a point 3 m below the turbine the pressure is 124 kPa. What must the water flow rate be if the turbine output is 1.00 MW ... 

Wettability A qualitative term referring to the water- or oil-preferring nature of surfaces, such as the mineral surfaces in a porous medium (rock) of an oil-bearing reservoir. The flow of emulsions in porous media is influenced by the wetting state of the walls of pores and throats through which the emulsion must travel. See also Contact Angle. 

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