Process liquid cell

FIGURE 37.25 Process liquid cell for high pressure and high temperature liquids. (Courtesy of Speeae Ltd., UK.)... 

In contrast to many other surface analytical techniques, like e. g. scanning electron microscopy, AFM does not require vacuum. Therefore, it can be operated under ambient conditions which enables direct observation of processes at solid-gas and solid-liquid interfaces. The latter can be accomplished by means of a liquid cell which is schematically shown in Fig. 5.6. The cell is formed by the sample at the bottom, a glass cover - holding the cantilever - at the top, and a silicone o-ring seal between. Studies with such a liquid cell can also be performed under potential control which opens up valuable opportunities for electrochemistry [5.11, 5.12]. Moreover, imaging under liquids opens up the possibility to protect sensitive surfaces by in-situ preparation and imaging under an inert fluid [5.13]. 

Fig. 5.6. Cross-sectional view of a liquid cell for in-situ AFM measurements of surface processes.

We have also studied polysaccharide deposition processes during cell wall formation (7), by gas-liquid chromatographic analysis of fractions sep-... 

The SREF based fuel-processing, fuel cell, auxiliary, and overall system efficiencies of the investigated fuels are presented in Table 8. The values indicate that natural gas is the best option while there are only minor differences regarding the investigated liquid fuels. The slight differences observed between gasoline and diesel options are primarily due to the better heat integration of the latter. 

In contrast, it is easy to list all of the process parameters involved liquid input, qin, which leaves the cell divided into the flotate discharge, qFi, and the processed liquid output, qout releasable gas content of the liquid feed, qgas/qin = Hy Ap/pG gravitational acceleration g. (Hy is the Henry s law constant)... 

It is therefore more cost effective to use a large ultrasonic system supplying 80 kW to process liquids at a flow-rate of 10 m /h than to use 5 ultrasonic processors with a power of 16 kW each or 40 processors with a power of 2 kW each. The robustness of the transducer enables its use under heavy-duty industrial conditions. Also, the processor can be designed to be explosion-proof. Like the transducer and the flow cell, the generator is housed in two connected compact stainless steel cabinets. This makes the device self-contained, robust and easy to install. The standard footprint of a 16-kW system is just 600 mm x 1200 mm. 

Liquid-fluidized beds predate gas-fluidized beds, but they have considerably fewer applications because of a smaller number of advantages. Most applications are physical, with bioreactors being the sole significant reactor application. Much of the recent attention has focused on aerobic wastewater treatment and fermentation processes, e.g., with methane as the organic substrate (see Refs. " for more details). In these processes, microbial cells are attached to the surface of inert particles (e.g., sand or activated carbon) as a biofilm, or trapped within the pores or interior of particles, causing the particle size and/or density to vary with time. Loaded particles therefore have... 

The versatility of LEMs is clear. From the encapsulation of living cells to the removal of toxic or inhibiting substances, and in their use as a downstream process, liquid emulsion membranes remain a powerful and, as of yet, virtually untapped resource for biochemical engineers. The ability of LEMs to separate and concentrate amino acids demonstrated here gives strength to this observation, and it is anticipated that these systems will enjoy increasing attention in the years to come. 

The main effort as far as synthetic membranes are concerned is concentrated on the development of completely new membranes for processes such as pervap-oration, gas separation, membrane distillation, or as ion transferring separators in batteries, fuel cells or electrochemical production processes. Liquid membranes with selective carriers used today for the separation and concentration of heavy metal ions or certain organic compounds are being developed further to be used in gas separation. 

A result of no viable target organisms is found in the process liquid flow path, and no viable cells are detected on the clean sides, indicates that the column design provides an effective flow path for chromatography with no unswept areas, and that the cleanability is maintained. 

The gelation technology employs chemical interactions to cause liquid droplets to gel, forming microcapsules or microspheres. This technique is used by the pharmaceutical industry to encapsulate active agents and also to immobilize live cells and organisms. In one process, live cells are first entrapped in gel matrix beads produced by the reaction of sodium alginate with calcium ions. The outer layer of the beads is then hardened by treatment with a polycation to form a polyelectrolyte complex, while the interior of the beads is solubilized by treating with sodium nitrate to form a soluble complex. 

Also an onboard electrical power supply, e.g., by photovoltaic cells or thermogenerators coimected to a lab-frame irradiation source, would introduce additional, frequency-independent degrees of freedom, enabling a multi-force manipulation of the processed liquids. Another extension of present centrifugal systems is the (wireless) data communication with the lab-frame workstation for an improved process control and analysis. 

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