Laboratory centrifugation

A centrifuge on a crystallization process plant is to be scaled down for tests. If the plant centrifuge is 1.0 m diameter and rotates at 25 Hz at what speed should a 100 mm laboratory centrifuge run if it is to duplicate plant conditions ... 

Once equilibrium in the reagent mixture is attained, centrifugation in a common laboratory centrifuge, followed by decantation of the supernatant is all that is required for separation of bound and free label. 

High-speed homogenizer Laboratory mechanical shaker Laboratory centrifuge Polypropylene centrifuge bottles (250-mL)... 

Sufficient water is now added to the mixture to dissolve the pasty chromium salts (300-800 cc.). The mass of crystals is then rapidly filtered on a Buchner funnel and sucked as dry as possible. The crystals are then transferred to a small laboratory centrifuge and centrifuged for several minutes. The crystals are washed in the centrifuge with about 15-25 cc. of ice water, then with 10-15 cc- of cold petroleum ether, and finally centrifuged till as dry as possible. The crude dichloroacetone is dried in a vacuum desiccator over sulfuric acid overnight. It weighs about 220 g. 

General laboratory equipment, laboratory centrifuge, vortex mixer. 

Routine laboratory equipment Vortex mixer, 30°C shaking water bath, laboratory centrifuge, analytical balance and ultraviolet/visible spectrophotometer. 

Centrifuge the tubes for 10 min at about 3000 rpm (1800 x g) in a routine laboratory centrifuge to sediment the precipitate. 

Routine laboratory equipment vortex mixer, laboratory centrifuge, analytical balance, water bath, pH meter, HPLC system with fluorescence detection at 350/440 nm (for neopterin see 6.1.3.1, subheading Instrumentation ). 

Special laboratory centrifuges used in analysis and research are described in Refs 15,17,20,22, 24... 

Laboratory centrifuge Side-arm Erlenmeyer flask Buchner funnel Whatman no. 1 filter paper... 

Centrifuges—For harvesting the 10-liter culture, a continuous-flow centrifuge such as a Sharpies is most convenient. For washing the cells, a refrigerated high-speed laboratory centrifuge (e.g., Sorvall RC-2B) is necessary. 

Crystal samples out of a crystallizer must be separated from the solution and dried. The separation from the solution typically is done on a laboratory centrifuge or on a Buchner Funnel. The separated crystals are typically washed with alcohol on the separation device and air dried before screening. Some products require special separation techniques to avoid fines precipitation or agglomeration during separation of the... 

Discrete analysis, in contrast with continuous-flow analysis, allows each specimen in a batch its own physical and chemical space, separate from every other specimen. Early discrete analyzers, such as the 1970 vintage robot chemist, mimicked the steps of manual human analysis. Subsequently, many discrete analyzers were developed and are still widely used in clinical laboratories. Centrifugal and random access analyzers are examples of instruments that use discrete processing. 

Suction filters that are similar to Buchner funnels are often used in pilot plants. These filters may be used in many operations on a small scale. With relatively thick filter cakes, extended filtration times occur. To speed the removal of liquids (deliquoring) from the filter cakes, operations may use other types of filters, such as Nutsche filters, filter presses, and centrifuges [18]. Centrifuges are often used in manufacturing operations for the efficient isolation of solids. Laboratory centrifuges are available for studies before committing a process to scale-up. 

A laboratory centrifuge such as the Beaker design (Heinkel) can also simulate the operation of a filtering centrifuge and verify product characteristics, filtration rates and wash requirements. Various filter cloths can also be tried using only one liter samples. 

Using a thin artist brush, paint the PZT and the adhesive layer with a thin coat of polyurethane. Spin down at 500 for 5 min in an available spin coater, or in a laboratory centrifuge. 

Scale-up of these procedures is readily achieved using conventional laboratory equipment. A number of laboratory centrifuges are available for use up to the 6-L scale, and the Jouan 5.22 machine has a 9.6-L capacity. 

Recent work by Ratulowski et al. (2003) has demonstrated the use of a laboratory centrifuge to simulate reservoir-scale isothermal gravity segregation. Their work suggests that there is a very valuable place for carefully designed laboratory work in reservoir geochemistry to help understand field data. So far no laboratory work has been reported on combined thermo-gravitational equilibrium, despite some theoretical work. 

Nabivanets and Kudritskaya studied the solubility of an amorphous Th(OH)4(am) precipitate in 0.1 M NaC104 at (17 + 1)°C. The solubility was measured in the pH range 3.4 to 7.0 after equilibration times of 3-6 days. The Th concentrations were determined colorimetrically after centrifugation for 1 hour at 10000 rpm with a usual laboratory centrifuge. The measured solubilities, which decrease from 1.6 x 10 M at pH 3.40 to 5 X 10 M at pH 5.35-7.00, were described by assuming only the presence of mononuclear Th(IV) hydroxide complexes. The stepwise equilibrium constants for the reactions ... 

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