Cleaning testing

Reactions of Aspirin, (i) Distinction from Salicylic acid. Shake up with water in two clean test-tubes a few crystals of a) salicylic acid, (0) aspirin, a very dilute aqueous solution of each substance being thus obtained. Note that the addition of i drop of ferric chloride solution to (a) gives an immediate purple coloration, due to the free —OH group, whereas (b) gives no coloration if the aspirin is pure. 

Reduction of ammoniacal silver nitrate. Place about 5 ml. of AgNOj solution in a thoroughly clean test-tube, and add 2-3 drops of dil. NaOH solution. Add dil. ammonia solution, drop by drop, until the precipitated silver oxide is almost redissolved, then add 2 - 3 drops of formaldehyde or acetaldehyde. A silver mirror is formed. 

Reduction of ammoniacal silver nitrate. Place 2 ml. of dilute silver nitrate solution in a clean test-tube. Add 1 drop of NaOH solution and then add dil. ammonia drop by drop until the precipitate formed by the NaOH is just not redissolved. Now add 1-2 ml. of glucose solution and place the test-tube in a water-bath at 50-60° a silver mirror is produced in 1 - 2 minutes. 

It is preferable to use Tollen s ammoniacal silver nitrate reagent, which is prepared as follows Dissolve 3 g. of silver nitrate in 30 ml. of water (solution A) and 3 g. of sodium hydroxide in 30 ml. of water (solution B). When the reagent is requir, mix equal volumes (say, 1 ml.) of solutions A and JB in a clean test-tube, and add dilute ammonia solution drop by drop until the silver oxide is just dissolved. Great care must be taken in the preparation and use of this reagent, which must not be heated. Only a small volume should be prepared just before use, any residue washed down the sink with a large quantity of water, and the test-tubes rinsed with dilute nitric acid. 

While detail may be found in the ASTM D-3330 or PSTC-1 and PSTC-2 standards, the peel test is typically carried out as follows The tape is conditioned at 23°C and 50% relative humidity for 1 day. Next, the tape is rolled down with a weighted standard roller onto a clean test substrate (usually polished 302 stainless steel), allowed to dwell for a specified time (usually 1 min), and then clamped with the testing fixture in the test machine and peeled at a specified rate. 

Pour 3 mE of 2M sodium hydroxide into a clean test tube. Slowly add 3 mL of 0.2M copper(II) sulfate. 

Label one clean test tube INP and a second clean test tube H20. 

Pour 3 mL of saturated sodium chloride solution into a clean test tube. Add 6 drops of 12M hydrochloric acid. Record your observations in Data Table 1. 

Pour 5 mL of iron(III) chloride and potassium thiocyanate solution into each of three clean test tubes. 

Pour 2 mL of 0.1M cobalt(II) chloride solution into a second clean test tube. 

Pour 5 mL of the ammonia solution into another clean test tube. 

Pour about 5 mL of copper(II) sulfate solution into a clean test tube and add about 5 mL of sodium carbonate solution. Stopper and shake the test tube. 

Pour 2 mL of egg white into each of six clean test tubes. 

Textile prints score poorly in dry cleaning tests involving agents such as per-chloroethylene, a feature which is typical of Naphthol AS pigments. P.R.10 is affected by dry heat and is equally unsuitable for PVC coatings. The prints equal step 6-7 on the Blue Scale for lightfastness, depending on the depth of shade. 

P.R.12 textile prints are excellently lightfast 1/1 to 1/6 SD prints equal step 7 and 6-7, respectively, on the Blue Scale. However, the pigment fails dry cleaning tests and migrates considerably in PVC coatings. P.R.12 tolerates dry heat up to 150°C at 180°C, the pigment still largely retains its initial color value. 

P.R.112 is very lightfast on textiles 1/1 to 1/3 SD (deep shade) prints equal step 7 on the Blue Scale. Exposure to dry heat at 150 and 180°C has no effect. However, like other members of its class, P.R.112 fails the dry cleaning test with per-chloroethylene. The pigment may not be brought into contact with PVC coatings, into which it bleeds. 

Make the melting-point tubes as described on p. 40 from a clean test tube the internal diameter should be about 4-5 mm. Cut off pieces about 5 cm. long. Close the lower ends by sealing as uniformly as possible, also keeping the walls as thin as possible. By drawing the softened glass away sideways avoid reducing the bore more than a little. 

Repeat steps 1-6 using a clean test tube, about 8.0 g of BHT, and about 1.0 g of the unknown. 

However, even against this background of uncertainty and apparent imprecision, in some cases it is possible to measure airborne asbestos with acceptable precision through replication for a reasonable price. Since there is no exposure standard, "clean" must be defined by comparing indoor and outdoor levels. A statistical comparison of indoor versus outdoor measurements that is significantly different from zero indicates that the indoor space is not clean. Tests may be designed chat either compare the average of... 

Thus, the above results for the Upper Freeport coal indicate that density-based processes (e.g., float-sink separation) should be able to remove significant amounts of mineral matter, while surface-based processes (e.g., froth flotation) will likely be unable to reduce the mineral content significantly. Results of cleaning tests reported elsewhere [5] have generally verified these predictions. 

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