Float method

The majority of commercial LB troughs use the Wilhehny plate method for measurement of surface pressure (II), although some use the alternate Langmuir float method. The plate material most commonly used is cut pieces of filter paper, of negligible cost and completely wetted by water. The other type of plate used is a piece of high-purity platinum metal, which can be cleaned in a flame and gives a reproducible contact angle with water of 60°. 

Examples of mixed post-consumer plastic waste by the combination of a three-stage sink-float method and selective flotation have been presented. The appropriate conditions, e.g., wetting agents, frother, depressant, and pH condition, are of importance (122). 

S. Pongstabodee, N. Kunachitpimol, and S. Damronglerd, Combination of three-stage sink-float method and selective flotation technique for separation of mixed post-consumer plastic waste, Waste Manage. (Oxford), 28(3) 475—483,2008. 

Birefringence measurements were obtained by the Becke line method, and density measurements were obtained by the sink-float method (26). 

Balog P. S., Secco R. A., and Rubie D. C. (2001) Density measurements of liquids at high pressure modifications to the sink/float method by using composite spheres, and application to Fe-10 wt.%S. High Press. Res. 21, 237-261. 

The floating method consists of floating the lightweight kernels from the more dense shells in salt or mud baths. A hydrocyclone can also be used to separate kernels and shells from an aqueous slrury. Kernels from these wet methods are free-drained on a vibrating strainer and then sent to a dryer for about 10 h. The dried kernels will average 6-7% moisture and approximately 50% pahn kernel oil. 

We have studied V and Ni transport in two catalyst blends. The first blend contained 75 wt.% ECAT with 2400 ppm V and 2400 ppm Ni blended with 25 wt.% Davison RV4+ metals trap [4].The second blend contained 75 wt.% of a commercial lab-deactivated catalyst impregnated with 4900 ppm V by Davison s CPS deactivation procedure [2], mixed with 25 wt.% lab-deactivated Davison metals trap (RV4+). These catalyst blends were tested at various reactor temperatures (675-750°C), catalyst average residence times in the reactor (14 -120 min), amounts of excess oxygen (0 to 3%), and steam levels in the reactor feed (0 to 30%). Samples of 20 - 40 g of catalyst were collected and separated by the sink-float method. 

The sink-float method requires a beaker, pipette, burette and two liquids. The liquids must be miscible and inert to the fiber being tested. One liquid must be less dense than the fiber and the other liquid must be more dense. A known volume of liquid A is pipetted into a beaker and the fiber is immersed in the liquid. The second liquid, B, is then added dropwise from a burette to the beaker with constant stirring. As the density of the liquid solution in the beaker changes, a point is reached where the density of the liquid precisely equals that of the fiber and the fiber will neither sink nor float but will remain suspended in the liquids. The volume of the second liquid added to the beaker is recorded and the density of the fiber is calculated ... 

There exist a number of familiar procedures for effecting mineral separations, including sink-float methods based on density differences and froth flotation based on wettability. Because of the tendency of kerogen to swell and soften in the presence of organic liquids and thus possibly to mobilize trapped mineral particles, and because most minerals are water-wetted and thus extractable with water, we investigated a liquid-liquid (oil-water) pelletization method. 

TABLE 6.12 Density (specific gravity) of some commercial deck boards. Data were obtained using sink/float method (see below)... 

DETERMINATION OF DENSITY OF WOOD-PLASTIC COMPOSITES USING A SINK/FLOAT METHOD... 

Sink-and-float methods. A sink-and-float method uses a liquid sorting medium, the density of which is intermediate between that of the light material and that of the heavy. Then the heavy particles settle through the medium, and the lighter ones float, and a separation is thus obtained. This method has the advantage that, in principle, the separation depends only on the difference in the densities of the two substances and is independent of the particle size. This method is also called heavy-fluid separation. 

Analysis and spectroscopic study. The elemental analysis was performed with anICP-6000 spectrometer. The precursors crystallization was studied by thermal analysis methods (TG85). The samples were analysed by IR spectroscopy (Nicollet, FTIR-7500) and powder X-ray diffraction (PXRD, DRON-3). The morphology of surface was studied by scanning electron microscopy (SEM) (JEOL, JSM-6100). The density of KTP particles was determined by a sink-float method. Local x-ray analysis was performed using Link ISIS microanalysis system (Si Li detector) mounted on Jeol 2000 FX microscope. Bruker-400 apparatus was used for P, C and H NMR study of precursor solution. The YAG Nd SHG was measured on LS-10 device. 

Three methods are common, viz, the liquid displacement method, the sink-float method and the density gradient column method. Each of these is a common, standard technique and is fully described in ISO 10119, 1992 (for the determination of the density of carbon fiber), and also in ASTM D 276-87 (reapproved in 1993), which in fact also refers to ASTM D 1505, ASTM D 792, and AATCC, Method 20 (1990) (Fiber identification), each of which deals with the above techniques. ISO 10119 is a very good and concise description of the techniques. However the measurement liquids specified in ISO 10119 of ethanol, methanol, acetone, tricloroethane, and carbon tetrachloride, although suitable for carbon fibers, are not at all suitable for the general range of textile polymers, with the exception perhaps of ethanol and methanol. ASTM D 276 87 recommends the use of / -Heptane for universal application, except, of course for the olefins, such as polyethylene. A range of typical fiber densities is given in Table 4. 

Sink-float methods are commonly used for quality control measurements for glasses. A sample is placed into a test tube containing an organic liquid which is slightly more dense than the sample. The tube is heated until the density of the liquid becomes less than that of the sample, whereupon the sample will begin to sink. If the test tube also contains a standard of known density, the difference in temperature at which the sample and standard sink can be used to calculate the difference in their densities, provided the temperature dependence of the density of the liquid is known. This method is capable of detecting differences in density of as little as 20 ppm. 

The density of PVA can easily be determined by a floating method in an appropriate mixture such as benzene nitrobenzene arbontetrachloride. Table 4.17 shows the density of PVA films with different DPs after heat treatment at various temperatures [85]. The range of DP of polyvinyl alcohol was 309 to 4570, and the range of temperature of heat treatment was 40 to 200°C. It is shown in Table 4.17 that the density increases with increasing temperature of the heat treatment. 

On his return in 1854, Humphreys was given charge in connection with surveys for railways from Mississippi River to the Pacific. In 1857 he resumed his woih on the Mississippi delta and in 1861 published with Henry Larcam Abbot (1831-1927) a notable work on the hydraulics of this large river. The report contains numerous velocity profiles measured with the double-float method, which was later not accepted as an accurate means, however. It also contains formulae for the velocity distribution and velocity under uniform flow conditions, yet these data have not been used after aroimd 1900, mainly because of the immense problems associated with prototype observations. 

Density Sink-float method Corn husk 7... 

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