2-5-Octamethylene tetrahydrophthalic anhydride does not form even a trace of the corresponding phthalic anhydride on dehydrogenation, but partly dissociates back into cyclododecadiene and maleic anhydride. 2-5-Nonamethylene tetrahydrophthalic anhydride dehydrogenates with considerable difficulty.
A survey of the heavy metal content of canned shellfish and crustaceans sold on the Canadian market has been made. With the exception of one sample of clams having 5 p.p.m. of lead, one sample of lobster having 13 p.p.m. of lead and, one sample of lobster having 7 p.p.m. of arsenic, of the 120 samples analyzed the values found were not significantly above the limits established for the heavy metal content of foods.
The effect of different amounts of starch and crude fat on humin formation during the hydrolysis of gluten prepared from a commercial flour depended on the acid/protein ratio, high ratios giving less humin nitrogen and less humin weight. The nitrogen content of humin was almost independent of the acid/protein ratio but increased with decreasing humin formation. Filtration time increased markedly with increasing purity of the samples. The color of the hydrolyzates varied slightly with impurities and acid/protein ratios.
The voluminous starch sludge or "squeegee" fraction, obtained with all known methods of wheat starch manufacture, consists of strongly hydrated pentosan masses in which starch granules are embedded. The pentosans of the bran and endosperm both contribute to the formation of these heterogeneous complexes. The "squeegee" starch fraction is not abolished by allowing the crude starch slurries to ferment, by exposing them briefly to mildly acid or alkaline solutions, or to C2−C12 monohydric alcohols. The pentosan and protein contents of this low quality starch fraction may be greatly reduced by 24–48 hr. digestion in dilute acid at pH 2.0 before recovering the starch on the centrifuge.
Experimental results are given for trials of the C.F.R. engine at 900 r.p.m. and 12: 1 C.R. on Toronto town gas alone and with an addition of hydrogen sulphide. The sulphide led to such severe preignition that measurements of power were impossible except for very weak or very rich mixtures. The former included the 50% weak mixture for which thermal efficiency is a maximum. The sulphide was then of beneficial effect, a maximum value of 44% for indicated thermal efficiency being obtained as compared to a maximum of 42.5% without it. The experimental results are interpreted in the light of combustion tube experiments showing that hydrogen in mixtures with air is not ignited by red hot surfaces on which it is oxidized with sufficient rapidity to steam, but that ignition occurs at relatively low temperatures if the surface reaction is inhibited by hydrogen sulphide. The conclusion is that fuel gases containing hydrogen in large proportion can be used for full power engine operation at compression ratios even higher than 12: 1 if the oxidation of the hydrogen in part to steam, on the hot surfaces in the combustion chamber, is not inhibited by the poisoning effect of the hydrogen sulphide commonly present in the gases.
The experiments described are part of a series being made to determine the factors which limit the power and efficiency of an Otto cycle spark ignition engine using Toronto town gas nearly free of sulphur. The air supply was unthrottled and power was varied by varying the gas supply. Mixture strength was "correct" at an air-to-gas ratio of 4:1. Trials were run with jacket coolant temperatures of 100°, 140°, 212°, and 295° F., the compression ratio being always 12:1 and the speed 900 r.p.m. A maximum indicated thermal efficiency of 43% was attained with coolant temperatures of 100° and 140° F. and an air-to-gas ratio of 8:1. Thermal efficiency diminished rapidly as air-to-gas ratio was increased and tended to become zero instead of the air standard value. The brake horsepower became zero for an air–gas ratio of approximately 11:1, the mixture strength being then 64% weak. Thus the engine was run at 900 r.p.m. from zero to full load, that is with 100% quality control. The maximum I.M.E.P. of 144 lb./sq. in. was obtained with a jacket coolant temperature of 100° F. The indicated thermal efficiency was then 36% and the mixture 10.7% rich. The performance of the Otto cycle engine could probably be improved by running at higher speeds but even at the relatively low speed of 900 r.p.m. for that type, it compared favorably in most respects with that of the compression ignition type of Diesel engine.
Measurement of air flow with variable orifice type flowmeters in laboratory experiments revealed discrepancies that could not be explained as errors arising from faulty calibration, leaks in the system, or failure to reduce readings to standard conditions of temperature and pressure. They were found to arise because of the occurrence of rapid pulsations in the air flow. A theoretical analysis of the effect showed that these instruments indicate root mean square rather than average flow rates. The results of experiments designed to test the theory were in reasonable agreement with the predicted values. It was found that errors arising from the occurrence of pulsations could be minimized by insertion of a suitable smoothing device between the pump and flowmeter. For example, an orifice with a pressure drop of 40 cm. of water reduced the flowmeter error to 5% of the true flow rate.
The polymerization of isoprene has been initiated by peroxide–peroxidase, by various inorganic and organic catalysts, and by air oxidation and anodic oxidation. At moderately high conversion, polymers of isoprene have shown zero gel content and a dilute solution viscosity from 1.5 to 4. The physical properties of some of the polymers have been measured either in our laboratories or those of the Polymer Corporation of Canada.
It is shown that with natural rubber, vulcanized to soft "gum" rings, extension curves after the first are in two parts, and that the second part does not develop except after severe previous extensions.With molded rings, stretched initially a few per cent short of rupture, these effects are very marked, and the fifth extension curve is in two clearly separate parts with a sharp inflection at 380% elongation. The equations fitting both parts of this curve are of the form:[Formula: see text]In these equations, the two K 0 L terms intersect at L = 0, and the equations also show a number of other coincidences which strongly suggest that they must be of significance as related to the elasticity of rubber after fatigue has produced a stabilized structure.It is also shown that with these fatigued rings no hysteresis occurs within the range from 0 to 110% elongation, irrespective of the range of the elongation and retraction cycle; that extensions within the range from 0 to 380% elongation show no hysteresis on retraction; but that hysteresis commences abruptly if 380% elongation is exceeded.Hysteresis effects for a "small loop" also differ markedly, depending on whether the loop is initiated from an elongation or retraction curve, and continued cycling round this "small loop" does not remove this difference.Since the equations for both parts of these extension curves are of exactly identical form, although hysteresis occurs in one part but not in the other, it is suggested that the basic cause of elasticity of rubber cannot be considered as in any way related to any molecular arrangement factors, but must be of a kinetic nature, and it is shown that if it is assumed that the rubber chain is vibrating, and that tension in the chain restricts this vibration, the forces developed would be quite adequate to explain the elasticity.It is also shown that with fatigued rubber the S shape of the extension curves is entirely destroyed if forces are calculated on the basis of force per unit area under stress, while this is only approximately the case for the usual extension curves.It is suggested that if the extension curve for rubber, and possibly other substances, is extended back to L = 0, it should give an intercept equal to the internal pressure in the substance, i.e., that Young's modulus represents the internal pressure of the substance.
A hysteresis test has been developed which measures directly the energy loss per cycle of elongation. Six samples are stretched, like the spokes of a wheel, between a small disk and a large disk. The large disk is motor driven, and the small disk, mounted on a ball bearing, is displaced eccentrically with respect to the larger disk. In the elongation cycle which each sample undergoes with each revolution, the hysteresis causes an average force on the small disk which is normal to the eccentric displacement and is proportional to the energy loss per cycle. A lever and balance system makes it possible to measure this force continuously while the machine is running.Measurements were made on gum stocks of Hevea and five commercial synthetic elastomers. Testing conditions included temperatures, T, of 0°, 35°, 70°, and 105 °C., frequencies, f, of 5 and 50 c.p.s., mean elongations, e, of 50, 100, and 200%, and elongation amplitude, A, 25%. Absolute hysteresis, H, (loss/cycle-(amplitude)2) at first decreases with increasing e and then flattens or goes through a minimum. Hysteresis decreases with increasing T. The temperature coefficient between 0° and 35 °C. is very large for Hycar. Hysteresis usually increases with f, but only slightly in most cases; and Hevea at e = 400% shows a reversal of frequency effect, which is presumably associated with crystallization effects.Under the same test conditions, the hysteresis of the synthetics is 10 to 20 times that of Hevea.When the hysteresis data for all synthetic stocks at various temperatures are plotted against T–Ts, Ts being second order transition temperature of the respective elastomer, the data lie within a rather narrow band. From this it is concluded that the hysteresis of synthetic elastomers arises from the same molecular forces which cause hardening and embrittlement at and below Ts.
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.
A simple, rapid polarographic procedure for the determination of titanium in paint pigments has been developed, using a sulphuric acid – tartaric acid medium. The accuracy and precision of the method are satisfactory for routine testing operations. The interference of other common pigment ingredients is discussed, and a procedure suggested for the removal of copper and antimony prior to analysis.
An electromechanical instrument has been developed, which adds, subtracts, multiplies, or divides the ordinates of two curves in Cartesian co-ordinates, plotting the resulting locus. This uses the principle of the Wheatstone bridge, and is semiautomatic; the curves are followed manually, but a phase-sensitive servo system keeps the bridge in balance. Attachments are provided for determining the area under the resulting curve, and also for the performance of certain logarithmic operations of interest in photometry. In the ordinary use of the computer, the accuracy is about 0.3% of full scale or better.
The sorption of the dye Orange II by wool has been determined at the boiling point in the presence of various concentrations of sulphuric acid and of sodium sulphate within the range usually found in practice. Some experiments were also carried out with hydrochloric acid and sodium chloride. It is shown that the results for any one acid and salt concentration can be represented by a simple relation which has the same form for all results. Although this relation has the form of an adsorption isotherm, it remains purely empirical at present. The salt effect is readily explained on the basis of the Donnan equilibrium. The effect of acid strength is to fix the saturation value for the dye.
The amount of carrageenin extracted from a sample of rinsed Chondrus crispus increased linearly with temperature of extraction up to 100 °C., and more slowly thereafter up to 110 °C. Increasing the temperature to 125 °C. had no further effect on the yield. Heat treating carrageen or replacing the calcium and potassium in it with sodium increased the yield of carrageenin at lower temperatures.The viscosity of carrageenin extracts obtained at different; temperatures increased and the concentration required to increase the viscosity of milk to 15 centistokes (i.e., the "suspending concentration" for cocoa in milk) decreased with temperature of extraction up to 60 °C. Above this temperature the viscosity decreased and the suspending concentration increased. The increase in viscosity is attributed to the extraction of higher polymers of carrageenin with increased temperature; the decrease, to heat depolymerization during extraction. Neither the solubility nor the fractionation studies gave any indication of chemically distinct carrageenin components. The essential difference between carrageenin that was most effective if incorporated with cold milk and carrageenin that was most effective if incorporated with hot milk was that the former was of high suspending concentration. A method of evaluating carrageen which gives soluble carrageenin divided by suspending concentration was tested but the results were sensitive to variations among samples of milk. When the same milk was used, the correlation coefficient between the concentration required to give viscosities of 15 centistokes in milk and in 0.05 N sodium chloride for 12 samples was.93. Viscosity in 0.05 N sodium chloride is preferred for evaluation of carrageen.
The averages and ranges for thiamine in approximately 250 samples of cereals tested, expressed as μgm. per gm., were: barley 4.2 (3.3–5.7), oats 6.7 (3.8–8.6), wheat 4.5 (3.4–5.9); for riboflavin: barley 1.3 (0.9–1.6), oats 1.3 (1.0–1.7), wheat 1.2 (1.0–1.4). There was a marked increase in the thiamine content of oats over that for 1946—amounting to 0.7 μgm. per gm. Barley and wheat showed slight increases. The values for riboflavin in the three cereals grown in 1947 were about the same as those for the 1946 samples. Varietal effects on thiamine content differed somewhat from those observed in 1946. For barley, Garton, OAC21, Sanalta, and Montcalm were about equal and slightly better than Plush. The order of thiamine content of wheat—for those varieties of which more than 10 samples were tested—was Carlton, Regent, Redman, Thatcher, and agreed with the findings for the previous year. Durum wheats showed higher thiamine levels than spring wheats. There was no varietal effect on the thiamine content of oats. There was no varietal effect on riboflavin content of any of the cereals. None was observed for the 1946 samples. For 1946 no soil zone effect on vitamin content of any of the cereals was noted. In 1947 rendzina and black earth soils produced wheats with higher thiamine contents. An environmental effect other than that for soil zone on the thiamine and riboflavin content of wheat and oats was confirmed.
Monthly samples of cleaned weed seed screenings and of screenings oil (commercially solvent extracted) examined over a six-month period indicated that the composition of the screenings varied widely but that of the oil was remarkably constant. The composition of the weed seed was: wild mustard, mostly Brassica arvensts (53–79% av. 68%) mixed weed seeds (13–35%, av. 23%), crop seeds (4–10%, av. 6.6%), and broken and unidentified seeds (1–6% av 3%) The average characteristics of the oil were: iodine value, 124; saponification number, 182; free tatty acid (as oleic), 2%; relative light transmission (cf. mineral oil), 5% at 440 mμ, 18% at 540 mμ, 26% at 660 mμ. Appearance of the oil and response to processing were similar to those of rape and mustard seed oils. Small scale taste panel tests indicated that processed screenings oil was generally not as palatable as corn or cottonseed salad oils, but that screenings shortening was generally as acceptable as the control (commercial vegetable shortenings) the screenings shortening had a satisfactory smoke point and good baking volume properties.
In comparative tests for ascospore formation by 43 different yeast strains a solid medium containing acetate and dextrose was shown to be superior to two other sporulation media. Ascospores were formed more frequently and in greater numbers on the former medium. Eleven cultures of the thirty forming ascospores on acetate–dextrose agar yielded 50% or more asci, and seven cultures formed asci only on this agar medium.
The ability of soaps to prevent the deposition of carbon black and other materials on fabric during the detergent process has been investigated. In general the suspending power of the soap solutions studied increased rapidly with increasing soap concentration, and reached a maximum at a relatively low concentration. At higher concentrations the suspending power either remained constant or decreased slightly. With carbonaceous soils the indicated suspending power for a given soap increased, in general, with increasing particle size and decreasing "structure" of the carbon. With various soiling materials differences were encountered, not only in the magnitude of the indicated suspending power, but also in the form of the curve obtained on plotting suspending power vs. soap concentration. As measured by one type of carbon black (Standard Micronex) only minor differences were found between suspending powers of sodium myristate, palmitate, and stearate, all of which were higher than that of the laurate. Increasing temperatures caused a decrease in the suspending power of the lower chain length soaps (C12, C14) and an increase in the suspending power of the longer chain soaps (C16, C18). The suspending power of sodium oleate was essentially unchanged by temperature variations over the range 25–80 °C.
