Gravimetric separation systems

Gravimetric separation systems. These include jigs, shaking tables, Humphrey-type spiral concentrators, and so on. 

The TRUclean soil washing system is a patented, ex situ modular process that uses soil washing, size fractionation, and gravimetric separation techniques to remediate soils contaminated with radionuclides and heavy metals. The technology developer, Lockheed Martin Corporation, claims... 

If the spike flow is not assessed gravimetrically, the mass flow of the spike flow has to be calibrated by a reverse isotope dilution technique. A standard solution of natural isotopic composition with the concentration Cgt, is injected into the separation system. The spike flow My t) is calculated using equation 7.4a ... 

For adsorption measurements a known mass (usually 0.500g) of silica 186 was contacted with 20 cm of polymer solution and the system gently agitated at 25° for 20h., after which the supernatant was separated by centrifugation and the solute concentration determined gravimetrically. 

In order that the soHds robotic system could be vaHdated fully, each separate step or component of the procedure was isolated and the results verified gravimetrically. The vahdated results showed that the TS, TSS, and TDS-ROE robotic methods performed excellently in terms of precision, accuracy, and method detection Hmit (MDL). These results were found to be equivalent to, or better than, results obtained by manual... 

Effect of Dust Storm Episodes on the Average Weekly Aerosol Concentrations. The total and fine gravimetric mass averaged over all sites for each week, is depicted in Figure 6. The error bars for the Owens Valley curves represent the standard deviation of the mean. The errors on the Mono Lake curve represent the sampling system error of 15%. The mean weekly values do not include the three dust storm episodes sampled separately, but do include several additional dust storms. Table I lists all the dust storms reported by the sampler operators. 

Rochette and Koskinen (1996) developed a system that uses supercritical C02 to remove pesticides from the aqueous phase of an unsaturated soil without first requiring the separation of the solution from soil. Using this technique, sorption coefficients were found to increase with increasing organic carbon and clay contents for three field-moist soils. Moreover, sorption significantly increased in sand as gravimetric moisture content increased from 4% to 16%, and in a silt loam as moisture increased from 9.6% to 27%. 

Cumene Cracking Reactions on Separated Fractions. Cumene cracking reactions were tested on a gravimetric setup the basic flow diagram for the reactor system is shown in Figure 1. The reactor determines both the activity of the catalyst (cracking of cumene to benzene and propylene) and the instantaneous rate at which coke is deposited on the catalyst (polymerization of the propylene). Conversion of the cumene is adjusted to exclude the amount of cumene disproportionation which yields benzene and diisopropyl benzene. 

Treffry, T. Sheth, B., "Gravimetric Analysis of Phase Systems Using a Microwave Oven and the Rapid Determination of Phase Diagrams," Separation Using Aqueous Phase Systems. Applications in Cell Biology and Biotechnology., Plenum Press, New York, NY, (1989). 

The general guidelines for developing a gas separation process based on adsorption are reviewed. Two important industrial cases based on adsorption processes are selected the separation of propane/propylene mixtures and n/iso-paraffins mixtures. The 13X zeolite and Ag -Amberlyst were used as adsorbent for propane/propylene mixture taking into account information from the open literature. The 5A zeolite was selected for n/iso-paraffins system the adsorption equilibrium and diffusivity data were obtained from gravimetric and ZLC techniques respectively. A mathematical model for the bulk separation in fixed bed upon non-isothermal non-adiabatic conditions is formulated and solved numerically. The simulated results are compared with the available experimental breakthrough curves. Finally, a cyclic process based in the PSA-VSA and TSA concepts is proposed for these systems. 

Panels (8.9 x 15.2 x 0.235 cm) were cut consecutively, at all possible locations, from commercial chrome-tanned grain-split blue stock cattlehide. Untreated control panels were included with each treated panel. In the emulsion method, after a separate 30 min conditioning period with the potassium persulfate-sodium bisulfite redox initiator system, the panels to be treated were tumbled at ambient temperature under emulsion conditions with the appropriate monomer for 24 hr. Composite composition was obtained gravimetrically from methanol or air-dried panels. Homopolymer was removed from apparent bound polymer by hot benzene extraction. Standard conditions were water 5 1 based on dry leather ... 

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