THE suspended impurity in the air can be measured by two methods, the automatic recorder or filter, and the jet dust counter method. The former was designed primarily for measurement of smoke pollution, and depends upon filtration of the air through white filter paper, the resulting discoloured spot being compared with a calibrated scale of shades. In the dust counter method the results are independent of the colour of the particles, a count of their number as well as an examination of their size, shape, and nature being made microscopically. Curves showing the numerical value of the suspended impurity for different cities and its variation from hour to hour can be plotted from the average figures for a large number of days. The cities selected for this purpose were London, Rochdale, Blackburn, Glasgow, and Stoke-on-Trent.
AbstractIn order to assess, and possibly find a method of reducing, the explosion huard in the manufacture of acetic acid from acetalde‐hyde, a knowledge was required of the range of acctaldehyde‐oxygen‐nitrogen mixtures capable of propapating flame under wrious conditions. The limits of inflammability in such mixtures were therefore determined for upward, horizontal and downward !lame‐propagation in glass tubes of I‐, 2‐ and 3‐in. diameter at room temperature and at soo C. The effect of contamination with carbon dioxide, acetylene and acetic acid was also examined, as well as that of using aluminium tubes in place of glass. The range of inflammability in the acetaldehydroxygen‐nitrogen system is exceptionally wide and offers little hope of eliminating explosion risks in the manufacture of acetic acid, the best safeguard being to minimize free space and place suitable guards at vulnerable points.The results show that in acetaldehydc∼∼gen‐nitrogen mixmres, the lower limit is mainly a function of the acetaldehyde content, whereas the upper limit is mainly determined by the oxygen content; this suggests that the calorific value Of the gas is an important factor in limit propagation. Another important factor in the case of acetaldehyde is the apearancc of the ‘cool’ flame. This causes a marked extension of t!e upper limit, from which it is inferred that the products of ‘cool’ flame combustion are incompletly oxidized, the main constituent being possibly acetic acid.
AbstractThe efficiency of palladized asbestos in continuously removing oxgyen from a steady stream of cylinder hydrogen is investigated. Moisture produced from the reaction magnified image which is catalysed by the palladium catalyst, is absorbed and weighed: the results obtained at various temperatures are used to find out how far the catalyst can bring the reaction to completion.It is shown that the total oxygen present can also be estimated by this method.
AbstractPhloroglucinol in the presence of hydrochloric acid gives a red colour with certain aldehydes, lignified tissue, the mould product viridin and oxidized hydroquinone; it is also said to give a red dour with compounds containing allyl groups. These reactions have been investigated. A number of aldehydes and oxidized hydroquhones give the reaction but pure allyl compounds do not. The aldehydes and hydroquinones may be distinguished by the use of phloroglucinol derivatives in place of phloroglucinol itself.
AbstractThe mechanical propcrtics of a plasticized polymer are gencnlly admitted to depend to a large extent on the viscosity of the plasticizer. It is shown that the tempernture dependence of the viscosity of a plasticizer may be less than that of a polymer, and that the addition of a plasticizer to a polymer may reduce the sensitivity of the systcm. This conclusion is in opposition to a common interpretation of the viscosity thcory of plasticizer action, but is shown to bc in accordance with experiment.
