摘要:

The MacBeth illuminometer is a well known portable photometer of the visual type. Measurements of its errors show that the instrument gives reliable results if used with care. The most serious errors may occur when the color temperature of the light that is being measured differs greatly from that of the working standard lamp in the instrument. Under such conditions, different observers may obtain widely different results.

ISSN:1923-4287    

DOI:10.1139/cjr48f-008

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

Laboratory studies on the thiamine, riboflavin, and niacin contents of longissimus dorsi muscles and of spent pickle indicate that there was little or no destruction of these vitamins during the curing process but that approximately 24% of the thiamine, 12% of the riboflavin, and 29% of the niacin were leached from the meat. The losses due to leaching increase with greater relative pickle volumes and are greater from an exposed surface of lean meat than from a surface covered with fat or rind. The commercial practice of rebuilding spent pickle probably reduces the over-all vitamin losses.The losses of thiamine and of riboflavin incurred during the cooking of pork were found to be considerably greater than those incurred during the cooking of bacon. Niacin was lost to about an equal extent from both pork and bacon. The stabilization of the thiamine and riboflavin that occurred during the curing process was sufficient to offset the losses during cure and thus, after cooking, bacon was as good a source of these vitamins as pork.

ISSN:1923-4287    

DOI:10.1139/cjr48f-009

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

The water-softening ability of soda ash, trisodium phosphate, sodium meta-silicate, tetrasodium pyrophosphate, and sodium hexametaphosphate was investigated. Each builder possessed great water-softening power and in each case the reaction with hardness was immediate and the residual hardness from maximum softening was less than 1 grain per gallon of water. The effect in detergent solutions of builders at concentrations that had given maximum softening in the above tests was investigated by determining soil removal, degradation, and deposit of insoluble compounds after 10 launderings of standardly soiled flannelette. In these relatively high concentrations the alkaline builders gave inferior detergency to that of soap alone in hard water. The sequestering agent, sodium hexametaphosphate, gave results that were superior to soap alone in hard water and equal to that of soap alone in soft water. In every instance the addition of builder before soap produced the same effect as builder with soap.

ISSN:1923-4287    

DOI:10.1139/cjr48f-010

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

There is described an apparatus for determining the sensitivity of detector papers toward gases from liquids of low volatility. The paper holder is constructed in such a way that the papers may be moistened, dried, removed, or replaced without disturbing the flow of gas through the rest of the apparatus. The holder also makes possible the comparative testing, under identical conditions, of a number of papers. With auxiliary apparatus, the paper holder permits the use of a carrier air stream of controllable relative humidity.

ISSN:1923-4287    

DOI:10.1139/cjr48f-011

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

UsingStaphylococcus aureusandEschericha colias test organisms, the influence of various concentrations of skim milk on the germicidal potency of Roccal and of Dalglish hypochlorite solutions was studied. Both germicides retained their activity in the presence of unexpectedly high concentrations of skim milk, especially againstS.aureus. Small concentrations frequently showed a slight potentiating effect in both laboratory and plant tests. The effectiveness of the hypochlorite fell off sharply beyond a certain concentration, while that of Roccal declined more gradually. Solutions of Roccal prepared with tap water were decidedly less active againstE.colithan those prepared with distilled water. With the hypochlorite, tap water solutions were equally effective. AgainstS.aureus, a similar difference was noted although to a lesser extent. Added skim milk depressed the germicidal action of tap water solutions of Roccal to a greater extent than for distilled water solutions, while for the hypochlorite the reverse held true.

ISSN:1923-4287    

DOI:10.1139/cjr48f-012

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

Salted butter from two Canadian plants was stored in parchment wrappers and in cans at −1.1°, 10.1°, 21.1°, and 32.2 °C. (30°, 50°, 70°, and 90° F.). Deterioration of the stored samples was followed by assessment of flavor, and by determination of: total acidity, free acidity, amino acid, pH, and fluorescence of the butter serum; peroxide oxygen, free fatty acids, and fluorescence of the butterfat; acidity of the whole butter; the number of viable, proteolytic, lipolytic, and oxidase positive organisms; and yeast and mold counts.Butter in cans deteriorated less rapidly than print samples although differences were less pronounced at 70° and 90° F. than at 30° and 50° F. Canned samples did not change appreciably in quality during 45 weeks' storage at 30° F. In general, decomposition of the serum and flavor deterioration became evident before changes occurred in the fat fraction. Stability of the serum was the limiting factor in keeping quality. The formation of amino acids and intermediate products of protein decomposition contributed largely to flavor changes.Flavor scores were more closely related to chemical objective test values than to microbiological counts. Storage temperature showed a marked influence on the correlation of objective test values with flavor score. Of the objective tests studied, total serum acidity (amino acidity plus free serum acidity) pH and serum fluorescence were most closely associated with flavor score.

ISSN:1923-4287    

DOI:10.1139/cjr48f-013

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

The antiknock effect of metallic dope is attributed to the catalytic action of the surface, maintained in an oxidizing atmosphere by continuous deposition thereon of the metal of the dope, to oxidize the fuel in part to steam and carbon dioxide, the consequent dilution of the end gas causing a reduction of inflammability sufficient to prevent completion of combustion in other than the normal manner. Experiments indicate that temperatures required for the necessary catalytic activity are attained during the period of flame travel; not prior to ignition. In support of the theory experimental evidence is given showing that, (a) steam is especially effective to reduce inflammability, (b) doped pentane or hexane oxidizes without ignition to steam and carbon dioxide only in reaction chamber No. 10, described in Part I, at any temperature of reaction, (c) the carbon dioxide–steam reaction is inhibited by a sulphur catalyst poison and the similar action in the engine destroys the antiknock effect of the dope. It is shown further by experiments with and without additions of a catalyst poison toundopedengine fuel that, in conditions leading to high surface temperatures in the combustion space, a carbon dioxide–steam reaction having a considerable antiknock effect is obtained. The engine experiments with catalyst poisons are completed by obtaining conditions in which tetraethyl lead becomes a pro-knock. It is recognized that the catalyst theory depends fundamentally on the oxidation of hydrocarbon fuel being a heterogeneous reaction as indicated by the experiments described in Part II, and some further evidence in support of the view, obtained by using catalyst poisons, is given in this Part.

ISSN:1923-4287    

DOI:10.1139/cjr48f-014

出版商:NRC Research Press    

年代:1948

数据来源: NRC