摘要:

AbstractDuring two trial famigations of empty bags in barges with methyl bromide, the penetration of this gas was studied by the measurement of gas concentrations. In the second trial, the loaded barge was also treated with hydrogen cyanide, so that a strict comparison could be made between the performances of the two fumigants. The rates of airing were also compared. The data demonstrate the grater suitability of methyl bromide for the fumigation of empty bags in barges.

ISSN:0368-4075    

DOI:10.1002/jctb.5000650901

出版商:John Wiley&Sons, Ltd    

年代:1946

数据来源: WILEY

摘要:

AbstractAn experimental investigation has been made into the effects of a number of factors on the results of stove analysis of natural sands. The factors studied included samples size, particle size distribution in the sample and the duration of sieving. Microscopic examination showed that the particle shape was similar in all the materials tested regardless of size. The work showed that overloading of the sieves leads to inaccurate results, and that reduction of sample size is a more effective remedy for overloading than prolongation of sieving time. Values are given for the maximum desirable loading for a number of sieves, and recommendations are made for the adoption of a standard weight of sample for sieve analysis of natural sands. The most recent British Standard method for Sieve Analysis (B.S. 882:1944, Appendix B) has been based on this work.

ISSN:0368-4075    

DOI:10.1002/jctb.5000650902

出版商:John Wiley&Sons, Ltd    

年代:1946

数据来源: WILEY

摘要:

AbstractThe percentage recovery of VitaminAin the unsaponiflable matters from commercial South African hake, soupfin shark, dogfish, kabeljou and geelbek liver oils has been determined for a large number of samples and characteristic values for each type of oil have been established. Hake liver oils were exceptional in giving recoveries not significantly different from 100%, while recoveries from the other types of oils averaged from 93‐95%, and wore unaltered when the oils wore diluted with vegetable oils such as an employed in margarineo compositions. No explanation of the different recoveries if given, but possible causes are discusse

ISSN:0368-4075    

DOI:10.1002/jctb.5000650903

出版商:John Wiley&Sons, Ltd    

年代:1946

数据来源: WILEY

摘要:

AbstractA description is given of the nature of external boiler deposits and of the methods used for examination. Special considerations attach to the collection of deposits from boilers if a maximum of information regarding their formation is to be obtained. The analytical difficulties arising from the presence of such radicals and elements as sulphate, phosphate, arsenic and boron (which may interfere with the normal procedure) are discussed, and methods for avoiding these difficulties are suggested. A rapid method is given for the determination, us mixed sulphates, of sodium and potassium in the water soluble fraction of a deposit.

ISSN:0368-4075    

DOI:10.1002/jctb.5000650904

出版商:John Wiley&Sons, Ltd    

年代:1946

数据来源: WILEY

摘要:

AbstractThe methods in use at B.C.U.R.A. for the analysis of external boiler deposits rich in phosphates are described. A special procedure is recommended where the phosphate concentration (as P2O2) exceeds 6%, sulphates also being present. It is recommended that a known excess of ferric sulphate be added for the removal of phosphate to the solution prepared for the precipitation of mixed oxides. Methods for the determination of phosphate, sulphate and alkalis are also included.

ISSN:0368-4075    

DOI:10.1002/jctb.5000650905

出版商:John Wiley&Sons, Ltd    

年代:1946

数据来源: WILEY

摘要:

AbstractMethods in use at. B.C.U.R.A. for the analysis of the water‐soluble fraction of boiler deposits arc described. A method is given for the extraction of the water‐soluble fraction of an external boiler deposit. The scheme of analysis outlined separates the solution of the water‐soluble fraction into three parts for determinations of (1) acidity, (2) sulphate and alkalis and (3) silica, mixed oxides, lime and magnesia, methods for which are desc

ISSN:0368-4075    

DOI:10.1002/jctb.5000650906

出版商:John Wiley&Sons, Ltd    

年代:1946

数据来源: WILEY

摘要:

AbstractThe adsorption of water vapour on wool at atmospheric pressure of air at 5 to 20% relative humidity, has been shown to be influenced by the action of light, the effect of irradiation being to increase the moisture content. The magnitude of the change is of the order of 0·3‐0·5% increase on a moisture content of 5% at 12% relative humidity at 20°. The effect, which has been observed at both 20° and 35°, is rapid and reversible. The phenomenon has not so far been observed with a synthetic vegetable protein

ISSN:0368-4075    

DOI:10.1002/jctb.5000650907

出版商:John Wiley&Sons, Ltd    

年代:1946

数据来源: WILEY

摘要:

AbstractAn electronic timing device is described, which is designed to operate a magnetically‐controlled reflux dividing head for stills using a total condenser. The timing unit is constructed of readily obtainable radio components and can be assembled by anyone with a good knowledge of electricity. The dividing head is constructed of glass, is suitable for operation at atmospheric or reduced pressure and calibration is virtually independent of the properties of the liquid. The whole is suitable for use by plant operative

ISSN:0368-4075    

DOI:10.1002/jctb.5000650908

出版商:John Wiley&Sons, Ltd    

年代:1946

数据来源: WILEY

摘要:

AbstractThis paper describes a technique for preparing dispersions of pigment particles suitable for electron microscope examination, and gives illustrations of the extent of the information, as to the shape and size of pigment particles, to be gained from the extremely high resolving power of the electron microscope. Some of the precautions to be taken in interpreting the micrographs are stressed.

ISSN:0368-4075    

DOI:10.1002/jctb.5000650909

出版商:John Wiley&Sons, Ltd    

年代:1946

数据来源: WILEY

摘要:

AbstractThe reaction between phenol and formaldehyde, takes place us a series of step‐wise reactions which are catalysed by both acids and bases and which proceed under neutral conditions at sufficiently high temperatures. Two types of reaction take place, namely the reaction of formaldehyde with phenol or a phenolic molecule, to form phenolic alcohols containing reacting methylol groups, and the subsequent condensation of these phenolic alcohols with phenol or a phenolic molecule to form larger molecules with elimination of water. Two studies of the initial portion of the reaction between phenol and formaldehyde in aqueous media are described, namely the Kinetics and the Thermochemistry.Kinetic studies show that a linear relationship exists between antilog (—pH) and the initial rate at which the formaldehyde reacts using HCl as catalyst between pH values of 1·3 and 3 at 100° and 80°. Catalysis by different acids at the same pH value gives rise to similar rates of reaction especially when pH and rate of reaction are measured at the same temperature. This points to catalysis by the hydrogen ion. The second order rate law is best obeyed by all the curves relating to formaldehyde reacted and time at various pH values, at 100° and 80° using HCl as catalyst. A decrease in temperature to 30° causes the rate law to approach first order. A theoretical enquiry shows that a decrease in order of reaction could be explained by the formation of dialcohols, which formation of dialcohols seems more probable at low temperature. In alkaline media, dialcohols also seem to be produced more readily, us indicated by the fact that a first order rate law is obeyed until about 45% of the formaldehyde has reacted.Thermochemical studies show that the heat evolved during the phenolformaldehyde reaction may also be regarded as derived from the reaction of formaldehyde with a phenolic molecule, and the subsequent elimination of water by condensation. The heats evolved per mole of formaldehyde reacted and water evolved are 4·1 and 16·9 kilocalories respectively. These values are confirmed by combining heats of combustion and heats of

ISSN:0368-4075    

DOI:10.1002/jctb.5000650910

出版商:John Wiley&Sons, Ltd    

年代:1946

数据来源: WILEY