Gases, centrifugalizing washing

Dilute to 10 ml with water (note a), precipitate PbS by saturating with HgS gas, centrifuge and wash the... 

Fig. 2.2. Simplified flow chart of the Phillips process (solution phase polymerisation) (Elias 1992). The solvent (for example isobutane), ethylene, co-monomers and the catalyst are fed into the reactor. The polymer solution is de sed (flashed) from the reactor through a gas separator after a certain reaction time. In a cleaning nnit (centrifuge, washing device, drier) the polymer is separated out and ethylene and solvent residues are processed. The polymer emerges in the drier in the form of snow white flakes. Flakes, carbon black, stabiliser and further additives, for example Ca-stearate, are mixed in a mixer and this mix is fed into an ex-tmder at an adequate mix raho with the polymer flakes. Here the mix is melted, homogenised and finally granulated. The black pellets are then transported to the storage facihties...

In the early days of ammonia manufacture, the average lifetime of the ammonia synthesis catalyst was limited to a few years, while today, lifetimes in excess of 10 years are common. This dramatic increase arises from a number of improvements. Most noteworthy are the introduction of centrifugal compressors and the application of lubrication oils with low sulfur content as outlined by Nielsen. Another significant improvement is the incorporation of a secondary ammonia condensation system, in which the make-up gas together with the recirculating gas is washed in liquid ammonia before entering the ammonia synthesis converter (see Fig. 8.1). 

Procedure Harvest the algal cells by centrifugation at 3000 rpm for 5 min at 4°C, then, wash the cells in distilled water thrice. Prepare three replicates for each treatment. Sonicate the algal cells under nitrogen condition at 14 MHz for 10 min to extract the membrane fatty acids. Add 2 ml of 2 M KOH in 95% (v/v) methanol and 2 ml of benzene to the sonicated cells. Fill the headspace with N2 gas and incubate the mixture at 80°C for 3 h. On cooling, add an equal volume of methanol and extract the non-saponified fraction by... 

Tris-HCl (120 gL), CaCl2 (60 gL), BSA (60 gL), DTT (3 gL), water (87 /iL) and freshly thawed microsomal fraction (30 gL) were mixed well and divided into three reaction tubes one reaction and two control tubes (1 and 2). 40 uL of freshly prepared UDPGA was added to the reaction tube and control 1 and 40 yfL of water to the control 2. The tubes were pre-incubated for 2 min in a water bath shaker at 35 °C. Then, 20 yiL of freshly prepared solutions of substrate in 20 % DMSO was added to the reaction and control 2 tubes, as well as 20 /rL of water to the control 1 mbe. Aliquots of 50 /rL were withdrawn from aU tubes and were quenched in acidified ice-cold methanol (160 gL per each 50 gL aliquot). The quenched aliquots collected during the incubation were left on ice for at least 20 min. After centrifugation for 10 min at 12000 rpm, the supernatants were collected into glass mbes and the remaining proteinaceous pellets were washed twice with 50 /iL of water and reprecipitated with 150 /iL of ice-cold methanol. The combined supernatants were dried under N2 gas and reconstimted into 50 /iL of appropriate mobile phase. 

Many metals in seawater can be preconcentrated for analysis by coprecipitation with Ga(OH)3. A 200-p.L HC1 solution containing 50p,g of Ga3+ is added to 10.00 mL of the seawater. When the pH is brought to 9.1 with NaOH, a jellylike precipitate forms. After centrifugation to pack the precipitate, the water is removed and the gel is washed with water. Then the gel is dissolved in 50 p,L of 1 M HN03 and aspirated into an inductively coupled plasma for atomic emission analysis. The preconcentration factor is 10 mL/50 p,L = 200. The figure shows elemental concentrations in seawater as a function of depth near hydrothermal vents. 

Narkis and Henfield-Furie [578] have described a direct method for the identification and determination of volatile water-soluble Ci C5 acids in municipal waste water and raw sewage. The method involves direct injection of the sewage into a gas chromatograph equipped with a Carbowax 20m on acid-washed Chromosorb W column and a flame ionisation detector. Preliminary preparation of the sample is limited to the addition of solid metaphosphoric acid to the sewage and removal of precipitated proteins and suspended solids by centrifuging. 

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