摘要:

AbstractExperiments carried out at B.C.U.R.A. in 1939‐40 in connexion with a programme of work on producers for road transport threw doubt on the conventional “two‐zone” theory of producer beds taught in the text‐books. In particular, an overwhelming proportion of the fuel was consumed within the first few particle thicknesses. Temperature measurements and gas analyses of samples taken at a series of points throughout the bed gave evidence of an apparentincreasein the total energy of the gases (per unit quantity of ingoing air) on passage through the bed. The only possible explanations are: (a) systematic errors in temperature measurements, (b) systematic errors in gas analyses such as would arise if energy in some latent form were yielded up to the sampling probes. Check measurements with suction pyrometers rendered (a) highly improbable. The most probable explanation was considered to be that carbon monoxide produced as a primary combustion product of the surface reaction between carbon and oxygen bums in the voids where it reacts with the surviving oxygen. Experiments in which air was streamed through a carbon tube at 850° showed that the oxygen removal and nearly the whole of the carbon consumption took place within a path‐length roughly equal to a single tube diameter. This length being quite insufficient for all the oxygen to reach the carbon surface (even with a certain degree of turbulence), this experiment is taken as providing substantial evidence as to the truth of the above working hypothesis. It appears, moreover, that mere thermal quenching is insufficient to “freeze” the reaction between CO and surviving oxygen. This would be at once intelligible if the reaction followed a “chain” mechanism as it doesin vitro.Attempts were therefore made to inhibit the gas phase reaction by introducing small quantities of volatile chlorine‐containing materials with the ingoing air, which was carefully freed from moisture. Only minimal quantities of CO2, now appeared in the outgoing gases, and the oxygen survival and carbon consumption were now appreciable after path lengths of about 10 tube‐diameters. Finally, it was found possible to muse partial inhibition of CO2, formation by the use of solid inhibitors (clean fused silica) remote from the carbon surface. These results were obtained at temperatures such that no appreciable reduction of CO2, to CO would take place.The above findings carry important implications in regard to technical fuel beds, which begin to function 85 producers after a path length equivalent to a single particle diameter has been traversed by the ingoing air. In particular it is ordinarily necessary to run with excess air since the physical mixing of the broad stream of producer gas with secondary air is otherwise incomplete. A burner which climates this disadvantage and gives combustion gas “by first intention” has been designed and is in the proc

ISSN:0368-4075    

DOI:10.1002/jctb.5000680101

出版商:John Wiley&Sons, Ltd    

年代:1949

数据来源: WILEY

摘要:

AbstractThe anti‐thiamin effect of bracken, noted by Weswig, Freed and Haeg, has been confirmed. Rats on a diet containing 40% bracken, and providing adequate amounts of thiamin, lost weig it and died within thirty days. Control groups receiving large supplementary doses of thiamin made continuous increases in bodyweight. The hearts and livers of rats which had succumbed to a bracken‐containing diet were shown to be of abnormally low thiamin content. An incubation technique developed by the authors, showed that bracken had the capacity to inactivate large amounts of vita

ISSN:0368-4075    

DOI:10.1002/jctb.5000680102

出版商:John Wiley&Sons, Ltd    

年代:1949

数据来源: WILEY

摘要:

AbstractThe isolation of tetramine (tetramethylammonium hydroxide) as the iodide from the root ofCourbonia virgarais described, and its distribution in various pans of the plant is recorded. The presence also of di‐ and trimethylmine has been proved, and of quaternary bases other than tetramine induced. The carbohydrate material of the root is partly sucrose and partly araban, reducing sugars and starch being absent; while that of the seeds is mainly starch together with a little pentosan, sucrose and reducing sugars being absent. The constants and fatty acid composition of the root fat have been determined and the composition of the ash of the root is also given.We are indebted to the District Commissioner, Yirol, for providing material j to Dr. F. W. Andrews for botanical data; to Riad Eff. Mansour and Ahmed Eff. Hassan Zaki for much technical assistance; and to the Director, Sudan Medical Service, for permission to publish this pape

ISSN:0368-4075    

DOI:10.1002/jctb.5000680103

出版商:John Wiley&Sons, Ltd    

年代:1949

数据来源: WILEY

摘要:

AbstractThe fungistatic activity of 127 benzene derivatives is reported and their behaviour related to structure and, in less detail, to solubility. The aromatic nucleus is more effective than its saturated counterpart. The effect of hydrophilic and nitro groups substituted in the benzene ring can differ markedly according to the position of substitution relative to groups already present. Halogen substitution is generally beneficial and is less affected by position. Nuclear substituted 4‐hydroxyhenzoates seem to behave biologically as substituted benzoic acids rather than as substituted phenols. The introduction of alkyl groups and alkyl esterification and etherification are generally beneficial, although the increased activity usually approaches an upper limit in the alkyl series relatively early (three to six carbon atoms). The carboxyl structure of the add and ester appears to be important since the analogous carbonyl compound is definitely less active. Methylene groups between the benzene nucleus and the carboxyl group lower effectiveness.Although there is evidently a general trend between inhibitory activity and decreasing water solubility, data available for 34 compounds show many deviations from a simple linear relationship between the logarithms of both properties. An approximate ratio between solubilities in ethanol and water (available for 23 compounds) provides a rather more significant relationship. There remain discrepancies, however, for the one organism, as well as between organisms, that suggest the operation of more specific factors than those covered in simple solubility dat

ISSN:0368-4075    

DOI:10.1002/jctb.5000680104

出版商:John Wiley&Sons, Ltd    

年代:1949

数据来源: WILEY

摘要:

AbstractFurther work on resinenes is reported including hydrolysis, bromination, thermal decomposition, dehydrogenation, hydrogenation, and alk line permanganate oxidation. The resinenes give neutral and phenolic products on hydrolysis. Dehydrogenation with selenium gives neutral and phenolic products. Oxidation gives a benzenoid residue including benzene hexacarboxylic acid in addition to more complex water soluble acids. The significance of these results is discussed.

ISSN:0368-4075    

DOI:10.1002/jctb.5000680105

出版商:John Wiley&Sons, Ltd    

年代:1949

数据来源: WILEY

摘要:

AbstractTwo methods of causing polythene to adhere to metal are described, (I) the use of polyisobutylene soaked in a polymerizable compound which is subsequently polymerizedin situ, and (a) the use of molten polythene on a previously prepared lead surface.

ISSN:0368-4075    

DOI:10.1002/jctb.5000680106

出版商:John Wiley&Sons, Ltd    

年代:1949

数据来源: WILEY

摘要:

AbstractAn investigation has been made of the physical transformations with occur when γ aluminium trihydrate (gibbsite) is dehydrated by heat treatment, and the effect such transformations have on the adsorption activity and porosity of the material. Dehydration proceeds according to the scheme: trihydrate → monohydrate → alumina, no dihydrate being formed. Between 225° and 500° positions of equilibrium are established between the monohydrate and alumina and the adsorption activity is directly related to the degree of conversion to γ alumina. At 500° and higher temperatures, the material is converted wholly to γ alumina. This, unlike the tri‐ and monohydrates cannot be completely defined as it is a transitional product in a heat‐controlled solid reaction, its state being at first highly disordered but rearranging to an orderly state as the reaction proceeds. The adsorption activity of the material is directly related to the state of disorder. The particle size distribution of the material is unaffected by the heat treatment which it receives, hence the porosity of the final product can be controlled by selection of the starting material. Aluminas covering a wide range of activities can be prepared by simple heat treatment o

ISSN:0368-4075    

DOI:10.1002/jctb.5000680107

出版商:John Wiley&Sons, Ltd    

年代:1949

数据来源: WILEY

摘要:

AbstractThe solubility of water in methylene chloride and I: 2‐dichloro‐ethane over the temperature range ‐ 20° to 40° and 80° respectively has been determined. The vapour pressures of the solvents, alone and in admixture, have been measured, and the composition of the varour phases of the mixed solvents determined at 10° intervals. over the range 20‐50°. Evidence of the formation of azeotropes with water is given; boiling point: composition and vapour pressure: boiling point relationships are derived. Mixtures of the two solvents are found closely to obey Raoult's law. The results are discussed in the light of Hildebrand's theor

ISSN:0368-4075    

DOI:10.1002/jctb.5000680108

出版商:John Wiley&Sons, Ltd    

年代:1949

数据来源: WILEY

摘要:

AbstractWith a view to exploring the possibility of eliminating the explosion hazard in the manufacture of sodium azide, the limits of inflammability were de ermined in the upward, horizontal and downward directions for all mixtures of ammonia, nitrous oxide and air at normal Temperature and pressure in 2 in, diameter rubes. The range of inflammability was found to be greatest in mixtures containing no air, being 2·6‐71·9% of ammonia for upward propagation, 5·1‐71·6% for horizontal propagation and 6·8‐71·0% for downward propagation. Addition of air caused contraction of the inflammable range at both ends roughly in proportion to the amount of air added. The limits for mixtures of ammonia and nitrous oxide were also determined (a) in 3 in, diameter tubes to indicate the general effect of cross‐sectional area and (b) at 150° and 250° to show the effect of temperature. An increase in either the tube diameter or the temperature produced a slight widening of the limits. Mixtures of ammonia, nitrous oxide and air appeared to obey Le Chatelier's limit rule except for some discrepancy affecting lower limit mixtures. Other evidence confirmed the abnormal behaviour of nitrous oxide containing small amounts of ammonia. AS these mixtures were liable to explode violently, although apparently below the limit for normal flame propagation, their anomalous behaviour is attributed to the exothermic decomposition of nitrous oxide, probably catalysed by the presence of small amounts of ammonia. This reaction appeared to propagate by a mechanism more akin to detonation th

ISSN:0368-4075    

DOI:10.1002/jctb.5000680109

出版商:John Wiley&Sons, Ltd    

年代:1949

数据来源: WILEY

摘要:

AbstractThe essential oil of thePittosporum eugenoides, indigenous to New Zealand has been examined, and has been shown to be remarkable for the unusually high content (60°) of liquid paraffin which has been identified atn‐nona

ISSN:0368-4075    

DOI:10.1002/jctb.5000680110

出版商:John Wiley&Sons, Ltd    

年代:1949

数据来源: WILEY