Because of obvious complications it is too difficult to calculate the stresses in the cords of a tire. In this work the direct measurement of strains was undertaken. Two techniques will be discussed; (1) the measure of the increase in length of the cords in the outside ply, and (2) a radiographic technique in which the change in length of the cord elements, marked by steel wires, is followed by photographic methods. The measurements on a number of tires are presented. The cords in a tire are strained about 2% by the inflation pressure. When the tire is loaded some of the cords are thrown into compression and some into more tension. During the rotation of the tire the cords are thus subjected to a vigorous alternation of compression and tension (± 2%). At the same time the angles between the cords change by as much as two degrees. A few general applications are mentioned and their importance to the tire engineer is indicated.
{"title":"THE MEASUREMENTS OF STRAINS IN TIRES","authors":"D. Loughborough, J. M. Davies, G. Monfore","doi":"10.1139/CJR50F-045","DOIUrl":"https://doi.org/10.1139/CJR50F-045","url":null,"abstract":"Because of obvious complications it is too difficult to calculate the stresses in the cords of a tire. In this work the direct measurement of strains was undertaken. Two techniques will be discussed; (1) the measure of the increase in length of the cords in the outside ply, and (2) a radiographic technique in which the change in length of the cord elements, marked by steel wires, is followed by photographic methods. The measurements on a number of tires are presented. The cords in a tire are strained about 2% by the inflation pressure. When the tire is loaded some of the cords are thrown into compression and some into more tension. During the rotation of the tire the cords are thus subjected to a vigorous alternation of compression and tension (± 2%). At the same time the angles between the cords change by as much as two degrees. A few general applications are mentioned and their importance to the tire engineer is indicated.","PeriodicalId":9392,"journal":{"name":"Canadian journal of research","volume":"76 1","pages":"490-501"},"PeriodicalIF":0.0,"publicationDate":"1950-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72675429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Based upon an assumed mechanism of particle aggregation by shear-induced interparticle collisions, a new method of studying flocculation in suspensions of large particles is described, and representative results obtained with cellulose–fiber suspensions are presented. The method consists in subjecting the suspension to a reproducible condition of shear motion and analyzing the fluctuations in optical transmission coefficient electronically. An approximate statistical theory is presented on the basis of which a flocculation index (σ/N0) appropriate to the method is proposed. The index is a function of both the number and size of the aggregates. The flocculation index was found to decrease with increasing rate of shear and decreasing fiber length. The effect of concentration and of additives was investigated. Alternative experimental techniques are outlined and limitations to the present method are pointed out.
{"title":"FLOCCULATION IN SUSPENSIONS OF LARGE PARTICLES","authors":"S. G. Mason, C. Hubley, A. Robertson","doi":"10.1139/CJR50B-095","DOIUrl":"https://doi.org/10.1139/CJR50B-095","url":null,"abstract":"Based upon an assumed mechanism of particle aggregation by shear-induced interparticle collisions, a new method of studying flocculation in suspensions of large particles is described, and representative results obtained with cellulose–fiber suspensions are presented. The method consists in subjecting the suspension to a reproducible condition of shear motion and analyzing the fluctuations in optical transmission coefficient electronically. An approximate statistical theory is presented on the basis of which a flocculation index (σ/N0) appropriate to the method is proposed. The index is a function of both the number and size of the aggregates. The flocculation index was found to decrease with increasing rate of shear and decreasing fiber length. The effect of concentration and of additives was investigated. Alternative experimental techniques are outlined and limitations to the present method are pointed out.","PeriodicalId":9392,"journal":{"name":"Canadian journal of research","volume":"117 1","pages":"770-787"},"PeriodicalIF":0.0,"publicationDate":"1950-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78317635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The nonreducing sugar in wheat leaves is probably entirely sucrose. It is the only abundant sugar. Free reducing sugars are absent, or almost absent from wheat leaves grown under the conditions described. The reducing power in the cleared alcoholic extracts of the leaves is, at least, partly due to degradation products of ascorbic acid. Other nonsugar reducing substances also are apparently present. The alcohol insoluble residue from wheat leaves contains little or no fructosan, dextrin, or starch at the two and one-half week old stage. Satisfactory methods for extracting and determining the sucrose are described. The following methods gave satisfactory results with wheat leaf extracts: the reducing power methods of Hanes and Somogyi after acid or preferably invertase hydrolysis, Ost's solution for fructose residues, the method of Neuberg and Strauss, the colorimetric resorcinol method. The latter method gives only approximate values for fructose residues unless the sugar concentration is high; the method...
{"title":"Qualitative and quantitative determination of the wheat leaf carbohydrates.","authors":"D. Roberts","doi":"10.1139/CJR50C-049","DOIUrl":"https://doi.org/10.1139/CJR50C-049","url":null,"abstract":"The nonreducing sugar in wheat leaves is probably entirely sucrose. It is the only abundant sugar. Free reducing sugars are absent, or almost absent from wheat leaves grown under the conditions described. The reducing power in the cleared alcoholic extracts of the leaves is, at least, partly due to degradation products of ascorbic acid. Other nonsugar reducing substances also are apparently present. The alcohol insoluble residue from wheat leaves contains little or no fructosan, dextrin, or starch at the two and one-half week old stage. Satisfactory methods for extracting and determining the sucrose are described. The following methods gave satisfactory results with wheat leaf extracts: the reducing power methods of Hanes and Somogyi after acid or preferably invertase hydrolysis, Ost's solution for fructose residues, the method of Neuberg and Strauss, the colorimetric resorcinol method. The latter method gives only approximate values for fructose residues unless the sugar concentration is high; the method...","PeriodicalId":9392,"journal":{"name":"Canadian journal of research","volume":"55 6 1","pages":"754-779"},"PeriodicalIF":0.0,"publicationDate":"1950-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90010266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The organic and inorganic requirements were determined for growth and pigment production by Pseudomonas nigrifaciens, an organism causing a reddish brown discoloration on the surface of mildly salted butter. Amino acids such as alanine, asparagine, proline, or glutamic acid were the best source of nitrogen for both growth and pigment production in a synthetic medium containing sodium chloride, inorganic salts, and glycerol; however, a carbohydrate was required only for pigment production in this amino acid medium. Na, K, Mg, S, P, and Cl or Br were also essential for both growth and pigmentation, larger amounts of these elements usually being required for synthesis of pigment than for growth. The dark brown-purple pigment produced was insoluble in all the common organic solvents hot or cold. With proline as a source of nitrogen a reddish-purple pigment developed which became deep purple then a deep brown purple. It is suggested that two pigments may be formed; one, a melanin-like dark brown substance orig...
{"title":"NUTRITIONAL REQUIREMENTS OF PSEUDOMONAS NIGRIFACIENS AS RELATED TO GROWTH AND PIGMENT PRODUCTION","authors":"H. Katznelson, A. H. White","doi":"10.1139/CJR50C-044","DOIUrl":"https://doi.org/10.1139/CJR50C-044","url":null,"abstract":"The organic and inorganic requirements were determined for growth and pigment production by Pseudomonas nigrifaciens, an organism causing a reddish brown discoloration on the surface of mildly salted butter. Amino acids such as alanine, asparagine, proline, or glutamic acid were the best source of nitrogen for both growth and pigment production in a synthetic medium containing sodium chloride, inorganic salts, and glycerol; however, a carbohydrate was required only for pigment production in this amino acid medium. Na, K, Mg, S, P, and Cl or Br were also essential for both growth and pigmentation, larger amounts of these elements usually being required for synthesis of pigment than for growth. The dark brown-purple pigment produced was insoluble in all the common organic solvents hot or cold. With proline as a source of nitrogen a reddish-purple pigment developed which became deep purple then a deep brown purple. It is suggested that two pigments may be formed; one, a melanin-like dark brown substance orig...","PeriodicalId":9392,"journal":{"name":"Canadian journal of research","volume":"97 1","pages":"706-715"},"PeriodicalIF":0.0,"publicationDate":"1950-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91465678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The optimum temperature for fermentation of seven strains of the Ford type of Bacillus subtilis is close to 45 °C. At these higher temperatures 10% glucose or equivalent hydrolyzed molasses ferments completely in six days while 10% fructose takes only three days. The rate of fermentation is similar under aerobic or anaerobic conditions but agitation or shallow layers of media increase this rate. The yields of 2,3-butanediol, acetoin, glycerol, and lactic acid are high under anaerobic conditions but in the presence of oxygen the yield of glycerol and lactic acid is decreased. The organism demonstrates strong oxidative tendencies and can give a large yield of acetoin. Other factors affecting the fermentation are also assessed.
{"title":"PRODUCTION AND PROPERTIES OF 2,3-BUTANEDIOL: XXXVII. A STUDY OF FACTORS AFFECTING THE BACILLUS SUBTILIS FERMENTATION","authors":"A. Blackwood, F. J. Simpson","doi":"10.1139/CJR50C-037","DOIUrl":"https://doi.org/10.1139/CJR50C-037","url":null,"abstract":"The optimum temperature for fermentation of seven strains of the Ford type of Bacillus subtilis is close to 45 °C. At these higher temperatures 10% glucose or equivalent hydrolyzed molasses ferments completely in six days while 10% fructose takes only three days. The rate of fermentation is similar under aerobic or anaerobic conditions but agitation or shallow layers of media increase this rate. The yields of 2,3-butanediol, acetoin, glycerol, and lactic acid are high under anaerobic conditions but in the presence of oxygen the yield of glycerol and lactic acid is decreased. The organism demonstrates strong oxidative tendencies and can give a large yield of acetoin. Other factors affecting the fermentation are also assessed.","PeriodicalId":9392,"journal":{"name":"Canadian journal of research","volume":"119 1","pages":"613-622"},"PeriodicalIF":0.0,"publicationDate":"1950-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75248137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Some of the general characteristics of the proteases liberated into the culture medium by molds and actinomycetes grown in submerged culture have been studied. Species of Alternaria, Streptomyces, Mortierella, and Gliocladium were used. The enzymes resemble trypsin in that they are most active at a pH slightly above 7 and are inhibited by a preparation of egg albumin. They are stable at low temperatures but suffer marked losses in activity when stored for 16 hr. above 40 °C. The most rapid hydrolysis of gelatin occurs at temperatures between 40 °C. and 50 °C. The enzymes from different organisms show definite differences with respect to their ability to attack different proteins, gelatin and casein being in general the most readily digested. The protease systems from different organisms also vary with respect to the extent to which they can digest gelatin; some enzymes are able to release about three times as many amino groups from gelatin as others. The limit of the hydrolysis is not dependent upon subst...
{"title":"THE PROTEOLYTIC ENZYMES OF MICROORGANISMS: III. SOME CHARACTERISTICS OF EXTRACELLULAR PROTEASES PRODUCED IN SUBMERGED CULTURE","authors":"W. Mcconnell","doi":"10.1139/CJR50C-036","DOIUrl":"https://doi.org/10.1139/CJR50C-036","url":null,"abstract":"Some of the general characteristics of the proteases liberated into the culture medium by molds and actinomycetes grown in submerged culture have been studied. Species of Alternaria, Streptomyces, Mortierella, and Gliocladium were used. The enzymes resemble trypsin in that they are most active at a pH slightly above 7 and are inhibited by a preparation of egg albumin. They are stable at low temperatures but suffer marked losses in activity when stored for 16 hr. above 40 °C. The most rapid hydrolysis of gelatin occurs at temperatures between 40 °C. and 50 °C. The enzymes from different organisms show definite differences with respect to their ability to attack different proteins, gelatin and casein being in general the most readily digested. The protease systems from different organisms also vary with respect to the extent to which they can digest gelatin; some enzymes are able to release about three times as many amino groups from gelatin as others. The limit of the hydrolysis is not dependent upon subst...","PeriodicalId":9392,"journal":{"name":"Canadian journal of research","volume":"40 1","pages":"600-612"},"PeriodicalIF":0.0,"publicationDate":"1950-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85764654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The dynamic and static friction on ice, the hardness, and the resilience of natural and synthetic rubber tire compounds were measured. General relationships were found to exist between friction and hardness of the rubber, friction and ice temperature, hardness and temperature, hardness and age of the rubber, resilience and hardness. Extraction of the rubber had a variable effect.
{"title":"ON THE FRICTION OF VARIOUS SYNTHETIC AND NATURAL RUBBERS ON ICE","authors":"P. Pfalzner","doi":"10.1139/CJR50F-044","DOIUrl":"https://doi.org/10.1139/CJR50F-044","url":null,"abstract":"The dynamic and static friction on ice, the hardness, and the resilience of natural and synthetic rubber tire compounds were measured. General relationships were found to exist between friction and hardness of the rubber, friction and ice temperature, hardness and temperature, hardness and age of the rubber, resilience and hardness. Extraction of the rubber had a variable effect.","PeriodicalId":9392,"journal":{"name":"Canadian journal of research","volume":"6 1","pages":"468-489"},"PeriodicalIF":0.0,"publicationDate":"1950-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88769582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Investigations into the biology of Septoria lycopersici Speg., a leaf-spotting fungus parasite of the tomato, reveal that this fungus species is composed of at least two physiologic races which show both qualitative and quantitative differences in their pathogenicity. Other factors, such as humidity, temperature, light, and host nutrition, which influence host–parasite interaction, have been shown to cause further variability in the symptomatological picture. Studies of spore germination and the prepenetration phase of host–parasite relationships suggest an interaction before actual penetration which, in some cases, is sufficient to condition the germination of the spores themselves. A minimum period of 48 hr. at saturation is required to promote germination and stomatal penetration, but this experience at high humidity need not be continuous. The fungus inhabits an intercellular locus, but is very intimately associated with the cells of the tissues parasitized. There is no evidence of action in advance; ...
{"title":"Studies in Septoria lycopersici Speg.","authors":"B. Macneill","doi":"10.1139/CJR50C-040","DOIUrl":"https://doi.org/10.1139/CJR50C-040","url":null,"abstract":"Investigations into the biology of Septoria lycopersici Speg., a leaf-spotting fungus parasite of the tomato, reveal that this fungus species is composed of at least two physiologic races which show both qualitative and quantitative differences in their pathogenicity. Other factors, such as humidity, temperature, light, and host nutrition, which influence host–parasite interaction, have been shown to cause further variability in the symptomatological picture. Studies of spore germination and the prepenetration phase of host–parasite relationships suggest an interaction before actual penetration which, in some cases, is sufficient to condition the germination of the spores themselves. A minimum period of 48 hr. at saturation is required to promote germination and stomatal penetration, but this experience at high humidity need not be continuous. The fungus inhabits an intercellular locus, but is very intimately associated with the cells of the tissues parasitized. There is no evidence of action in advance; ...","PeriodicalId":9392,"journal":{"name":"Canadian journal of research","volume":"8 1","pages":"645-672"},"PeriodicalIF":0.0,"publicationDate":"1950-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88866708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A survey of the more promising modifications of the Kjeldahl method for nitrogen determination indicates that the method using mercuric oxide as the catalyst as recommended by the Association of Official Agricultural Chemists is the most satisfactory. However small discrepancies were found when this method was applied to wheat leaves fractionated into soluble and protein (actually coagulable and indiffusible) nitrogen fractions. This method includes all the nitrate nitrogen in wheat leaves together with the organic nitrogen even when no pretreatment with salicylic acid is used. A simple and satisfactory method of separating coagulable and indiffusible nitrogen from soluble nitrogen in wheat leaves and seedlings is described.
{"title":"NITROGEN DETERMINATION IN WHEAT LEAVES","authors":"D. Roberts","doi":"10.1139/CJR50C-048","DOIUrl":"https://doi.org/10.1139/CJR50C-048","url":null,"abstract":"A survey of the more promising modifications of the Kjeldahl method for nitrogen determination indicates that the method using mercuric oxide as the catalyst as recommended by the Association of Official Agricultural Chemists is the most satisfactory. However small discrepancies were found when this method was applied to wheat leaves fractionated into soluble and protein (actually coagulable and indiffusible) nitrogen fractions. This method includes all the nitrate nitrogen in wheat leaves together with the organic nitrogen even when no pretreatment with salicylic acid is used. A simple and satisfactory method of separating coagulable and indiffusible nitrogen from soluble nitrogen in wheat leaves and seedlings is described.","PeriodicalId":9392,"journal":{"name":"Canadian journal of research","volume":"142 1","pages":"745-753"},"PeriodicalIF":0.0,"publicationDate":"1950-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91110852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Of 289 fungi and actinomycetes tested, only 20 were found to produce high yields of proteolytic enzymes when grown in submerged culture. Strains of Gliocladium roseum and Alternaria tenuis were found to be consistently proteolytic, and other good strains were also found in the genera Chaetomium, Sordaria, Epicoccum, Rhizoctonia, and Streptomyces.
{"title":"THE PROTEOLYTIC ENZYMES OF MICROORGANISMS: I. SURVEY OF FUNGI AND ACTINOMYCETES FOR PROTEASE PRODUCTION IN SUBMERGED CULTURE","authors":"W. Dion","doi":"10.1139/CJR50C-034","DOIUrl":"https://doi.org/10.1139/CJR50C-034","url":null,"abstract":"Of 289 fungi and actinomycetes tested, only 20 were found to produce high yields of proteolytic enzymes when grown in submerged culture. Strains of Gliocladium roseum and Alternaria tenuis were found to be consistently proteolytic, and other good strains were also found in the genera Chaetomium, Sordaria, Epicoccum, Rhizoctonia, and Streptomyces.","PeriodicalId":9392,"journal":{"name":"Canadian journal of research","volume":"162 1","pages":"577-585"},"PeriodicalIF":0.0,"publicationDate":"1950-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91208535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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