Measurement membrane apparatus

Research effort at Albany International Research Co. has developed unit processes necessary for pilot scale production of several species of reverse osmosis hollow fiber composite membranes. These processes include spin-dope preparation, a proprietary apparatus for dry-jet wet-spinning of microporous polysul-fone hollow fibers, coating of these fibers with a variety of permselective materials, bundle winding using multifilament yarns and module assembly. Modules of the membrane identified as Quantro II are in field trial against brackish and seawater feeds. Brackish water rejections of 94+% at a flux of 5-7 gfd at 400 psi have been measured. Seawater rejections of 99+% at 1-2 gfd at 1000 psi have been measured. Membrane use requires sealing of some portion of the fiber bundle for installation in a pressure shell. Much effort has been devoted to identification of potting materials which exhibit satisfactory adhesion to the fiber while... 

The apparatus used to measure membrane bubble points is shown in its simplest form in Figure 7.7 [4], Bubble point measurements are subjective, and different operators can obtain different results. Nonetheless the test is quick and simple and is widely used as a manufacturing quality control technique. Bubble point measurements are also used to measure the integrity of filters used in critical pharmaceutical or biological operations. 

Figure 35-8 shows one type of an apparatus for measuring membrane characteristics. The membrane is stretched between two flanges, greased, and held together with spring or screw type clamps. Pressure is obtained by nitrogen gas. A conductivity cell is used to measure solute concentration. 

Flux Measurement. The apparatus and procedure used to measure membrane fluxes was described in detail by Bateman et al. (19) and Way... 

Interactions between macromolecules (protems, lipids, DNA,.. . ) or biological structures (e.g. membranes) are considerably more complex than the interactions described m the two preceding paragraphs. The sum of all biological mteractions at the molecular level is the basis of the complex mechanisms of life. In addition to computer simulations, direct force measurements [98], especially the surface forces apparatus, represent an invaluable tool to help understand the molecular interactions in biological systems. 

The osmotic pressure is a property that has proven to be especially valuable in the study of solutions of macromolecules, including those of biologic and polymeric interest. The apparatus for measuring this quantity is shown schematically in Figure 7.10. Two compartments are separated by a membrane that will allow the flow of liquid solvent between the two chambers. If solvent is added, flow will occur until the liquid level on the two sides of the membrane is the same. 

Figure 7.10 Schematic representation of the apparatus for measuring osmotic pressure. The flow of solvent through the semipermeable membrane is followed by observing the movement of the meniscus of the flow indicator. The osmotic pressure II is the pressure that must be applied to the solution to prevent the flow.

FIG. 3 Apparatus for measuring electrical potential oscillation across the octanol membrane (a) octanol phase, (b) aqueous phase, (c) Ag/AgCl reference electrode, (d) KCl salt bridge, (e) saturated KCl, and (f) potentiometer. 

The other common laboratory method uses pressure plates and membranes to measure the amount of water held by soil at various pressures (Figure 5.15). One advantage of this method is that it gives a pressure value that can be used in many calculations relevant to movement of water in soil. The plates in the apparatus shown are used in the pressure range of -10 to -30 kPa. Other... 

Measurements of RO Performance. RO performances were measured by the simple apparatus, as shown in Figure 2. The water flux and salt rejection of the hollow fiber membranes under operating pressure in the range of 50 to 120 Kg/cm2c were determined using the feed water of 3.5 NaCl, at 25 C and at product water recovery ratio of less than 1 , after an elapsed time of 2 hrs. 

Early measurements in a steady-state flow apparatus showed that the meiTibrane viscometer allows the direct calculation of kinematic viscosities that are in good agreement with independent capillary viscometer measurements under limited conditions. Agreement is excellent when (1) the average polymer diameter is smaller than the membrane hole, that is, < D, and (E) the effluent flow rate or... 

The first utilization of the term artificial tongue dates to 1978, when H.W. Harper and M. Rossetto presented an apparatus based on conductance measurements able to mimic the taste stimulus delivery systems (Harper and Rossetto, 1978). This pioneering work has represented an isolated study for several years. The first example of a factual taste sensor was developed, in fact, by Toko and coworkers in 1990 (Hayashi et ah, 1990 Toko et ah, 1990). It was based on ion-sensitive lipid membranes and it was claimed to be able to respond to the basic tastes of the human tongue sour, sweet, bitter, salt, and umami. 

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