Influence of pH and cationic surfactant on stability and interfacial properties of algerian bitumen emulsion

The influence of water pH and cationic surfactant content on the interfacial properties and stability of an Algerian bitumen aqueous emulsion were investigated. While the stability was quantified by both the test-bottle method and size distribution measurements, the interfacial properties of the water–bitumen interface were assessed using interfacial tension measurements. Optical microscopy was also used to visualise the dispersed water droplets in the oil phase. The results showed that addition of the cationic surfactant at a concentration of 25 mmol L

Accuracy of Gercock™ Milkfat Test Bottles: Collaborative Study

No novel approaches to improving the accuracy of the Babcock test glassware for milkfat determination have appeared in years. Recent development of a test bottle wherein the calibrated neck of a Gerber bottle was attached to the bulb of a Babcock bottle showed promise. When the normal calibrated portion of the neck was changed from 8% to 5%, accuracy was further improved. Divisions between each percentage mark allowed 2× the accuracy in reading. Eight qualified testing laboratories collaboratively studied both 8% and 5% Gercock milkfat test bottles, using the AOAC method 16.065. Results were similar to those obtained by the Mojonnier method. Standard deviations were smaller among laboratories when the 5 % Gercock test bottle was used. Use of the 5% Gercock bottle has been adopted official first action as an addition in 16.065.

Calibration of Skim Milk-Test Bottles

The method described uses a 250 μL syringe to calibrate skim milktest bottles. Mercury is injected into the bore of the test bottle, and the amount is recorded. The bore of the bottle can contain 100 μL mercury, and those bottles shown to contain between 98 and 102 μL are acceptable for certification.

Air-entrained grouts suitable for post-tensioning

Grouts in post-tensioning ducts can cause cracking of the structural member if the grout freezes at an early age. This laboratory program examines a range of cement–water grouts with differing w/c ratios, air contents, and ages. A new empirical test method employing a test bottle was introduced to study the performance of grouts during early freezing.It was determined using the bottle method and other experimental and analytical procedures that excessive grout dilation during early freezing could be avoided if the entrained air content of the grout exceeded[Formula: see text]where w/c is the original water-to-cement ratio of the grout and M is the fraction of the cement that has hydrated before the grout freezes.

Anguillulina dipsaci on onion seed and its control by fumigation with methyl bromide

Further investigations on the occurrence of Anguillulina dipsaci on onion seed are presented. It is shown by the examination of 2,000 seeds individually that the parasite is usually located on the seed in the region of the hilum. A given seed may have as many as 4·7 worms or only 1 worm attached to it.A method of seed fumigation with methyl bromide is described whereby the parasites attached to seeds are killed but the seed is unharmed. By the use of a test-bottle technique it has been found that a minimum dosage of 600, i.e. a concentration-time product of 600 involving an exposure to the fumigant of 18 to 24 hours at 24°C. is necessary for the destruction of the parasites attached to the seeds and in such flower-part débris as may be mixed with it.The fumigant has no harmful effect on the vitality of the seed at dosages sufficient to destroy the parasite nor at much higher dosages. There is thus a wide upper margin of safety in its use. Two practical methods for the fumigation of large quantities of seed are described.The probable origin of seed-borne infection from lightly infected parent bulbs is discussed. It is shown that at the present time seedborne infection is fairly widespread and has been found to occur on at least 9 different varieties of onion seed as distributed by seed merchants. Recommendations as to control are made which it is suggested would go far to reduce the incidence of the disease in this country.