Keeping test

The problems that have been experienced in the recirculating rig test are indicative of those often met in performance testing. Attempts to reproduce the service conditions in a laboratory test inevitably involve attempting to reproduce each of the controlling conditions that exist in the real situation. Variations, which may be relatively small, in these simulations can lead to significant differences in test results. There is therefore much to be said for keeping test conditions as simple as possible rather than attempting to reproduce accurately the conditions in practice. A balance between reproducibility and realism has to be struck. 

YOU CAN MAKE A SIMPLE TEST TUBE STAND FROM A SALT BOX. CUT OUT SIDE AND USE CUT-OUT SECTION TO KEEP TEST TUBES LINED UP STRAIGHT. 

Rep Are you kidding We have over 8000 products and can t possibly keep testing them all ... 

To keep testing to a minimum, all available knowledge of the process must be employed. The volume of vessels and flow rates are always available, from which time constants may be calculated. The length and diameter of piping runs can serve to locate dead-time elements. By identifying all the known or knowable elements in this way, any tests will be of more value in defining the unknown elements which make up the balance of the loop. 

The eddy currents testing probe realization was satisfactory at the sight of the control and the testing results of coating samples. The fundamental parameters to keep in mind for a probe construction are ... 

Later, US NDT TD set up the National Certification Committee of Ukraine on NDT, which had the aim of organising the personnel certification in keeping with EN 473, rendered assistance to State Standardisation Organisation of Ukraine in setting up the Technical Committee on Standardisation Technical Diagnostics and Non-Destructive Testing (TC-78), the aims of which are in tune with those of lSO/TC-135. 

Dissolve 5 g. (5 ml.) of aniline in 50 ml. of warm dilute sulphuric acid in a conical flask and add 50 ml. of water. Place a thermometer in the solution, immerse the flask in a mixture of ice and water, and cool until the temperature of the stirred solution falls to 5°. Dissolve 4-5 g. of powdered sodium nitrite in 20 ml. of water, and add this solution in small quantities (about 2-3 ml. at a time) to the cold aniline sulphate solution. Keep tne latter well shaken and maintain the temperature at about 5° (see p. 183). When all the sodium nitrite solution has been added, transfer about 5 ml. of the cold solution to a test-tube for each of the following reactions. The remainder of the diazonium hydrogen sulphate solution must be kept in ice-water until required, and then when all the reactions have been carried out, the solution should be poured down the sink. 

Place about i g. of the base in a test-tube, and cover with concentrated (about 20%) sodium hydroxide solution. Bring the mixture gently to the boil, keeping the test-tube lightly closed with the finger meanwhile to prevent undue escape of vapour.. A.s the solution boils a strong fishy odour of dimethylamine is detected, and white fumes form when the test-tube is held near an open bottle of concentrated... 

Dissolve 20 g, (19 -6 ml.) of anihne in a mixture of 55 ml. of concentrated hydrochloric acid (1) and 55 ml. of water contained in a 350 ml, conical flask. Place a thermometer in the solution and immerse the flask in a bath of crushed ice (2) cool until the temperature of the stirred solution falls below 5°, Dissolve 16 g. of sodium nitrite in 75 ml. of water and chUl the solution by immersion in the ice bath add the sodium nitrite solution (3) in small volumes (2-3 ml. at a time) to the cold anihne hydrochloride solution, and keep the latter weh stirred with the thermometer. Heat is evolved by the reaction. The temperature should not be allowed to rise above 10° (add a few grams of ice to the reaction mixture if necessary) otherwise appreciable decomposition of the diazonium compound and of nitrous acid wih occur. Add the last 5 per cent, of the sodium nitrite solution more slowly (say, about 1 ml. at a time) and, after stirring for 3-4 minutes, test a drop of the solution diluted with 3-4 drops of water with potassium iodide - starch paper (4) if no immediate blue colour... 

Dissolve 36 g. of p-toluidine in 85 ml. of concentrated hydrochloric acid and 85 ml. of water contained in a 750 ml. conical flask or beaker. Cool the mixture to 0° in an ice-salt bath with vigorous stirring or shaking and the addition of a httle crushed ice. The salt, p-toluidine hydrochloride, will separate as a finely-divided crystalline precipitate. Add during 10-15 minutes a solution of 24 g. of sodium nitrite in 50 ml. of water (1) shake or stir the solution well during the diazotisation, and keep the mixture at a temperature of 0-5° by the addition of a httle crushed ice from time to time. The hydrochloride wUl dissolve as the very soluble diazonium salt is formed when ah the nitrite solution has been introduced, the solution should contain a trace of free nitrous acid. Test with potassium iodide - starch paper (see Section IV,60). 

Place 130 ml. of concentrated hj drochloric acid in a 1 - 5 litre round-bottomed flask, equipped ith a mechanical stirrer and immersed in a freezing mixture of ice and salt. Start the stirrer and, when the temperature has fallen to about 0°, add 60 g. of finely-crushed ice (1), run in 47 5 g. (46 5 ml.) of pure aniline during about 5 minutes, and then add another 60 g. of crushed ice. Dissolve 35 g. of sodium nitrite in 75 ml. of water, cool to 0-3°, and run in the cold solution from a separatory funnel, the stem of which reaches nearly to the bottom of the flask. During the addition of the nitrite solution (ca. 20 minutes), stir vigorously and keep the temperature as near 0° as possible by the frequent addition of crushed ice. There should be a slight excess of nitrous acid (potassium iodide-starch paper test) at the end of 10 minutes after the last portion of nitrite is added. 

The above test will detect 1 part of acetone in 500-1000 parts of isopropyl alcohol. The reagent should not be kept for more than 1-2 months since it deteriorates upon keeping. 

The following alternative procedure is recommended and it possesses the advantage that the same tube may be used for many sodium fusions. Support a Pyrex test tube (150 X 12 mm.) vertically in a clamp lined with asbestos cloth or with sheet cork. Place a cube (ca. 4 mm. side = 0 04 g.) of freshly cut sodium in the tube and heat the latter imtil the sodium vapour rises 4 5 cm. in the test-tube. Drop a small amount (about 0-05 g.) of the substance, preferably portionwise, directly into the sodium vapour CAUTION there may be a slight explosion) then heat the tube to redness for about 1 minute. Allow the test tube to cool, add 3-4 ml. of methyl alcohol to decompose any unreacted sodium, then halffill the tube with distilled water and boil gently for a few minutes. Filter and use the clear, colourless filtrate for the various tests detailed below. Keep the test-tube for sodium fusions it will usually become discoloured and should be cleaned from time to time with a little scouring powder. 

Liquid Fabric Softeners. The principal functions of fabric softeners are to minimize the problem of static electricity and to keep fabrics soft (see Antistatic agents). In these laundry additives, the fragrance must reinforce the sense of softness that is the desired result of their use. Most fabric softeners have a pH of about 3.5, which limits the materials that can be used in the fragrances. For example, acetals cannot be used because they break down and cause malodor problems in addition, there is the likelihood of discoloration from Schiff bases, oakmoss extracts, and some specialty chemicals. Testing of fragrance materials in product bases should take place under accelerated aging conditions (eg, 40°C in plastic bottles) to check for odor stabiUty and discoloration. 

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