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  • Author: P.J. Collins x
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Abstract

A system has been developed wherein the gas phase produced on smoking a cigarette through a Cambridge pad is analysed, on a puff-by-puff basis, for a desired component using automated colourimetry. The system consists of an AutoAnalyser I and a simple, 1-port smoking machine. The continuous gas stream from the smoking machine, either gas phase or intervening air, is passed concurrently with a stream of absorbing solution through a glass coil. Following passage through the coil, the solution is separated from the gas stream and introduced into the AutoAnalyser for continuous measurement of the concentration of the absorbed component. The entire system is calibrated using standard gas mixtures puffed in the same manner as the cigarette. The puff profile is essentially rectangular. Chief benefits expected from use of this system include the ability to obtain puff-by-puff measurements, a minimum time for reaction to occur in the gas phase and essentially no sample handling other than smoking the cigarette. The system has been utilized for the determination of hydrogen sulfide in gas phase using 0.1 N NaOH as the absorbing solution and the "methylene blue" colourimetric reaction. Results obtained on a variety of commercial U.S. brands ranged from 18 to 50 µg of H2S per cigarette, similar to results reported by other investigators using wet chemical methods. The accuracy of the results is supported by recovery tests wherein gaseous H2S added to the gas phase is completely recovered. The average relative standard deviations obtained with 11 U.S. commercial or reference cigarette samples using random selection of the cigarettes is 10.8 % for µg of H2S per cigarette and 8.8 % for µg of H2S per puff for a single cigarette. The basic system is thought to be applicable to the determination of a number of other components in gas phase.

Abstract

A procedure for the determination of CO in the gas phase of cigarette smoke has been developed. Cigarettes are smoked on a 20-port syringe-type smoking machine and the gas phase is sampled by a specially designed sampling unit without appreciably affecting the level of particulate phase components or the operation of the smoker. After mixing, the concentration of CO in the gas phase is measured by nondispersive infra-red analysis. All operations are carried out automatically except the initial start-up, calibration of the analyser, and calculation of results. The procedure has been applied to a variety of cigarette brands with results ranging from 1.2 to 2.0 ml of CO per puff. The precision of the procedure was determined by repeated analysis of a standard cigarette over a four-month period. For a single value representing 100 cigarettes, the relative standard deviation was found to be 2.2 % for ml of CO per cigarette and 1.1 % for ml of CO per puff.

Abstract

An automated procedure for the determination of total alpha-amino acids in aqueous solution has been developed which utilizes the Technicon Auto Analyser I. The procedure is based in part on a manual method proposed by Van Slyke wherein the CO2 produced in the reaction of amino acids with ninhydrin serves as a measure of the alpha-amino acid concentration. Evaluation of the procedure for the determination of alpha-amino nitrogen in extracts of flue-cured and Burley tobaccos indicates that adequately precise results are obtained which show a fairly high correlation (r = 0.8 to 0.9) with results by the classical Van Slyke nitrous acid procedure. The relation of the amino acid content of a variety of tobacco types, as determined by ion-exchange chromatography, to alpha-amino nitrogen results by the automated and nitrous acid procedures has been investigated. While the results indicate that neither procedure provides consistently accurate values for total amino acids in tobacco, it was found that the results by the automated procedure show a somewhat higher degree of correlation with total alpha-amino acids. It is therefore concluded that the automated procedure may be potentially useful in the evaluation of tobacco

Abstract

A procedure for the combined determination of total HCN and total gas phase aldehydes in cigarette smoke has been developed which is practical to use for the analysis of relatively large cigarette samples. The smoking system includes a Cambridge pad for collection of the particulate phase and a small tube of silica gel to trap gas phase components, with 5 cigarettes being smoked through each pad and trap. Following smoking, the Cambridge pad and silica gel trap are extracted; the silica gel extract is used for the determination of total gas phase aldehydes and the combined extracts for HCN analysis. Colourimetric procedures, automated through use of the Technicon AutoAnalyser as described previously, are employed for the analysis of the sample extracts. Evaluation of this combined procedure indicates that it yields reliable results for both total HCN and total gas phase aldehydes with greater speed and ease of operation than provided by the previously described methods. The procedure has been applied to various cigarette samples with the relative standard deviation for a single port of 5 cigarettes ranging from 1.9 to 5.5 % for gas phase aldehydes and from 2.6 to 8.4 % for total HCN.

Abstract

A procedure for the automated determination of ammonia in tobacco has been developed. Ammonia is extracted from the ground tobacco sample with water and is determined with a Technicon Auto Analyser system which employs separation of the ammonia through volatilization followed by colourimetry using the phenate-hypochlorite reaction. The procedure has been applied to a variety of tobaccos containing from 0.02 to 0.5 % ammonia with an overall relative standard deviation of 2 %. The accuracy of the procedure as judged by recovery tests and by comparison to a manual distillation method is considered adequate

Summary

The effects of low molecular weight phenolic resin impregnation and high pressure hot pressing (150°C, 30–100 MPa) on the physical and mechanical properties of wood were first investigated by using sawn wood prepared from a block of Japanese birch (Betula meximowicziana). Subsequently, the effects of element size and orientation were examined by using sliced veneers, particles and powder prepared from the remaining portion of the block. Due to the combination of resin impregnation and hot pressing under high pressure, the specific bending strength at 20°C and 65% RH of sawn wood increased 50% accompanied by enormous decreases in moisture content, and bending strength reached around 400 MPa. The mechanical properties of veneer laminated product did not differ significantly from those of sawn wood product. Among isotropic products, the highest bending strength at 20°C and 65% RH of plywood, particleboard and powderboard was 242 MPa, 166 MPa and 175 MPa, respectively. The difference of bending strength between plywood and other isotropic products could be explained by the difference in element orientation, cross lamination and random distribution. Furthermore, the results for the particleboard and powderboard showed that when the resin impregnated elements were hot pressed under high pressure, a decrease in element size did not result in a decrease in bending strength.

Summary

Thermal treatment on chromic (51Cr)-doped potassium Chromate results in the incorporation of 51Cr activity into the Chromate form. Measurements of the isothermal kinetics of this incorporation give "annealing" curves similar to those obtained in Szilard-Chalmers studies on potassium Chromate. It is concluded that transfer annealing may play an important role in Szilard-Chalmers annealing processes in potassium Chromate.