Platinum lengths

Plot the shape of the contact line pinned to a defect using Eq. X-30 for water on polyethylene, stearic acid, and platinum. Assume that the upper cutoff length is 2 mm. How does the shape of the pinned contact line compare with your observations of raindrops on dirty windows ... 

The apparatus (Fig. 82), which is constructed throughout of glass, consists of a pear-shaped bulb A (of about 5 ml. capacity) in which the solution is boiled, and which has a short length of platinum wire fused through its lowest point to assist steady boiling. The bulb A is connected near its base by a curved narrow tube B to a vertical condenser C, and from its apex by a similar tube D, undulating as shown, to the cup E. A larger outer cup F is fused to the lower neck of E as shown. 

It is the most corrosion-resistant metal known, and was used in making the standard meter bar of Paris, which is a 90 percent platinum and 10 percent iridium alloy. This meter bar was replaced in 1960 as a fundamental unit of length (see under Krypton). 

Thermal Properties. The thermal stabiUty of cellulose esters is deterrnined by heating a known amount of ester in a test tube at a specific temperature a specified length of time, after which the sample is dissolved in a given amount of solvent and its intrinsic viscosity and solution color are deterrnined. Solution color is deterrnined spectroscopically and is compared to platinum—cobalt standards. Differential thermal analysis (dta) has also been reported as a method for determining the relative heat stabiUty of cellulose esters (127). 

A typical anode for practical use would be in the order of 25 to 48 mm in diameter, with hard platinum alloy pins of 0-50 mm diameter by 10 mm length, spaced every 150 to 300 mm and progressively positioned around the circumferenceThe pins are a press fit into holes in the lead or lead alloy (approximately 01 mm diametric interference) and lie flush with the surface. The lead is peened around the pins to improve the mechanical and electrical contact. 

The products prepared at temperatures below 450° and above 600 0 have a lower activity and require a greater length of time for reduction to platinum black than those prepared at temperatures between 450° and 6oo°. 

Apparatus. Use the apparatus of Section 14.7. The generator anode is of pure silver foil (3 cm x 3 cm) the cathode in the isolated compartment is a platinum foil (3 cm x 3 cm) bent into a half-cylinder. For the potentiometric end point detection, use a short length of silver wire as the indicator electrode the electrical connection to the saturated calomel reference electrode is made by means of an agar-potassium nitrate bridge. 

A length of 6-7 mm of platinum wire of 0.5 mm diameter sealed into a glass tube is satisfactory electrical connection is made by means of a copper wire dipping into a little mercury in contact with the platinum wire. 

Table 3.11 Bond lengths (A) in palladium and platinum alkyls and aryls M(PR3)2R X...

The 4 1 complex has square planar coordination of platinum (Pt-S 2.317— 2.321 A) similar bond lengths are found in the corresponding complex with 1,4-thioxane [120]. Complexes with thiourea are important in Kurnakov s test (section 3.8.2) Pdtu4Cl2 has square planar coordination (Pd—S 2.33 A). 

Figure 3.100 Bond lengths in platinum(IV) ammine hydroxy complexes.

Table 3.27 shows bond lengths for a number of platinum(IV) and related platinum(II) complexes. 

Table 3.27 Bond lengths in platinum(II) and platinum(IV) complexes (A)...

Pulsed current experiments of aqueous acetate solutions indicate that at least in aqueous solution a platinum oxide layer seems to be prerequisite for the da arboxy-lation to occur. Only at longer pulse durations (> 10 s) is ethane produced [73,74]. These are times known to be necessary for the formation of an oxide film. At a shorter pulse length (<10"" s) acetate is completely oxidized to carbon dioxide and water possibly at a bare platinum surface [75]. The potent dynamic response in the electrolysis of potassium acetate in aqueous solution also points to an oxide layer, whose... 

Sample B provided platinum crystallites that were analyzed by both EDS and MAED. MAED of several 3 nm crystallites shows a wide variation of orientations with respect to the electron beam, however, many of the patterns match (111) and (110) orientations. An example of the MAED patterns observed Is shown In Figure 2. The diffraction pattern was made with a 25 pm objective aperture at a camera length of 2 m. 

Catalyst material Platinum Housing b diameter length 22 mm 40 mm... 

In a half-cell with a calomel RE, mercury purified by distillation and mixed with solid calomel is placed on the bottom of the cell. A length of platinum wire fused into glass tubing is fuUy immersed into the mercury in order to make electrical contact. 

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