摘要:

Contamination of starch syrups with copper was kept to a minimum by mixing the acid catalyst with the starch slurry rather than with the priming water. Copper removal at the neutralization stage was promoted by protein impurities in the converted starch, high pH, and hot filtration. Decolorization with activated carbon removed less than 20% of residual copper, whereas acid-tempered bone char removed over 99%. The copper content of dilute syrups was determined without preparatory ashing by precipitation with salicylaldoxime.

ISSN:1923-4287    

DOI:10.1139/cjr48f-028

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

Syrups prepared in semipilot plant equipment from wheat, corn, waxy corn, tapioca, and potato starches of low protein content were almost identical in taste and appearance. Differences in nature and amount of non-carbohydrate constituents did not necessitate modifications of the process. Wheat, corn, and waxy corn slurries hydrolyzed at approximately the same rate with 0.2% hydrochloric acid whereas potato starch hydrolyzed less rapidly. Contamination with 1.6% protein did not depress the hydrolysis rate but promoted foaming, turbidity, and bitterness. Loss of insoluble solids on the filter press averaged 1.25% for cereal and 0.3% for potato starch hydrolyzates. Complete decolorization of 14° and 30° Bé. syrup was effected by 0.5% activated carbon, based on the juice weight at each stage. Tap water promoted color development in the evaporator and inhibited color removal by active carbon. Color and fluorescence development in stored syrups was promoted by protein impurities, light, and tap water, and was strongly inhibited by sodium bisulphite. Syrups that remained colorless almost indefinitely were prepared from prime quality starches by using distilled water in the process and either acid-extracted carbon or bone char as decolorizing agents.

ISSN:1923-4287    

DOI:10.1139/cjr48f-029

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

Sensitivity to ignition of the three component system, calcium silicide, hexachloroethane, and zinc oxide, was studied. Apparatus is described and results plotted as isopotential lines on a trilinear chart. The investigation disclosed that mixtures of widely varying composition may be easily ignited and are therefore highly dangerous. Technological application of the deductions is discussed.

ISSN:1923-4287    

DOI:10.1139/cjr48f-030

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

A very simple method is given for operating the FP-54 Pliotron as a stabilized voltage amplifier with a grid current of less than 10−17 amp. The application of the method in the construction of a compact portable electrometer is discussed briefly.

ISSN:1923-4287    

DOI:10.1139/cjr48f-031

出版商:NRC Research Press    

年代:1948

数据来源: NRC