Teflon blocks

Typical Experimental Procedure (Plate Production). Production of an 80-member array was successfully completed using a Charybdis 96-well Teflon block, encapsulated in a Calypso reaction frame assembly. Reagents were transferred into the 96-well plate using either a Quadra 96 or Rapid Plate 96. The blocks were then heated at 65° for 3 days and the solvent evaporated in vacuo at 65°. Scavenging with PS-TsNHNH2 (6 equiv.) and PS-NCO (1 equiv.) was performed at the plate level and the resins were added using a Millipore column loader. Evaporation was performed in a Savant evaporator for 2 h. 

An alternative fibre forming technique involved the dissolution of curdlan in 1M NaOH to give a 525-7% w/v solution, which was cast onto a teflon block. After drying, the resulting film was washed in water and simultaneously stretched to produce a thin gel fibre. This was examined by X-ray diffraction under the following conditions ... 

Deuterated alkali gel. NaOD was dissolved in D2O to form a 1M NaOb solution. Curdlan was dissolved in this solution (5% w/v) and spread into a thin film on a teflon block. After drying, the film was washed in D2O to remove any excess heavy alkali and then allowed to dry. 

Film from Formic Acid. A solution (1% w/v) of the curdlan in formic acid was spread onto a teflon block and allowed to dry, forming a thin transparent film. 

A- Teflon Block B- Teflon Tubing (0.762-mm-o.d. and 0.305-ram-i.d.) C- Teflon-coated Fused Silica Capillary (367-flm-o.d. and 100- im-i.d.) D- Protein-bound Membrane E- Sample vial for collecting the Products... 

The valve body is machined from a carbon-filled Teflon block (75% Teflon, 25% carbon) (Ebolon), and the spools are made of polycarbonate with Viton O rings for seals. Teflon tubing is attached to the ports via Teflon 0-ring compression fittings. Two 24-V DC push-type solenoids position the spool. 

To test this model of the relationship of the surface absorption coefficient to the migration rate through the fissure, we constructed a model fissure. This was done by sealing a smooth slab cut from a basalt core to the face of a Teflon block that had a 0.0127-cm depression milled dovm its face. This then formed a Assure that was 0.0127 X 1 X 4 cm in size, tracer was dissolved in 10 ml of water and allowed to... 

Figure 26-18 A dialysis flow module. The membrane is supported between two grooved Teflon blocks.

The electrochemical cell consists of a Teflon block with three interconnected cylindrical wells (See Fig. 2.2). The counter electrode is a polycrystalline nickel disk (12.54 mm diameter) cast in Kel-F and then press fitted into an orifice bored on the Teflon block. The dynamic hydrogen reference electrode, is formed by inserting a platinum wire into... 

Material/shape Teflon block holding fritted polypropylene syringes fritted polypropylene syringes fritted deep-well plates... 

Material/shape Teflon block, cavities with frits polypropylene or glass syringes with frit... 

Methods combining the two approaches to some extent were used by Bein and coworkers [7], They designed a parallel autoclave block with wells drilled into a Teflon block with a size allowing solution volumes of some 100 pi. For product isolation, a filtration module could be integrated into the system after the reaction. In a later embodiment of the multiclave system, a centrifuge setup had been developed which allows separation and washing of the solid. The final product in both cases is collected on filter paper and is either analyzed manually or sequentially in an automated STOE transmission XRD setup [8, 9). 

Very interesting novel zinc phosphate structures were discovered in the group of Yu and Xu [12] using a combinatorial approach. The setup resembles the one initially described by Akporiaye [5] in that the well are formed in a Teflon block, with each well having a volume of about 800 pi. Product analysis was done with an automated powder XRD setup after the samples had been transferred to a sample holder. Solids were formed from zinc solution, phosphoric acid and N,N -dimelhylpiperazine as precursors. The most interesting material formed was a zinc phosphate with 16-membered ring channels in one direction, but two other structures with smaller pore openings were also described in this publication. 

Teflon Block Niiich I Holds the Faraday Plate While Isolating from Rest of the Electrode... 

Photographs of one of our STR PEM fuel cells are shown in Figure 3.4.The membrane-electrode-assembly (MEA) was pressed between two machined graphite plates press fit into Teflon blocks and sealed with a silicon rubber gasket. Gas plenums of volume Vg 0.2 cm were machined in graphite plates above a membrane area of lcm. There were several pillars matched between the two plates to apply uniform pressure to the MEA. Hydrogen... 

The cathode was a machined block of graphite with three parallel flow channels 2 mm x 2 mm x 30 mm long. The entire graphite block was press fit into a larger piece of Teflon for electrical isolation. The flow channels initiated and terminated in common manifolds in the Teflon block at either end of the graphite flow channels. The anode had the same chaimel structure, except that it was made of six graphite pieces separated by Teflon spacers inserted into a Teflon block, as shown in Figure 3.5A.An MEA was placed between the cathode and anode and sealed in the same way as for the differential fuel cell. 

Fig. 6.9 An automated electrochemical deposition system used for the production of metal oxides. The custom-made well plate shown has been designed fora 120-sample array, each sealed by 0-rings underneath a patterned Teflon block, and each containing a unique electrolyte composition. Reprinted with permission from [86], copyright 2005 American Chemical Society...

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