Colorimetric Estimation of Allyl Isothiocyanate Content in Mustard and Rapeseed Oils

A colorimetric method based on the colour reaction between allyl thiourea and potassium ferricyanide solution in dilute acetic acid has been developed for the determination of allyl isothiocyanate content in mustard and rapeseed oils. The method measures the optical density of the colour complex at 600 nm and it works in the range 2.5 to 7.5 μg of allyl isothiocyanate per ml of the colour solution. Mustard and rape oil samples analysed contain 0.40 to 0.6% of allyl isothiocyanate, with standard deviation of 0.002 to 0.016. The method takes around 3 hours and permits a number of sample analysis at a time.     

The gas-cooled fast breeder reactor critical experiments program

This paper presents results of measurements and calculations of physics parameters in the first gas-cooled fast breeder reactor (GCFR) critical assemblies in the US, a program of experiments conducted on the ZPR-9 facility at Argonne National Laboratory. Through a progressive three-phase series of assemblies, the major features unique to GCFR physics due to the gaseous coolant, and the resulting hard neutron spectrum and greater leakage, were investigated. Phases I and II were simple-geometry, uniform-core assemblies providing tests of nuclear data and GCFR design methods for fast reactors with large void fractions. The Phase III core simulates a GCFR design with three enrichment zones. This report primarily concerns the results obtained in Phase II.In addition to the usual central indices, reaction rate mappings, etc. these initial studies have provided the first experimental data on reactivity coefficients relevant to GCFR safety, such as worths of fuel, control, and cladding materials, Doppler effect, and coolant (helium) depressurization worth. Effects of steam ingress into coolant channels (due to a hypothesized steam generator leak) were simulated using polyethylene. The physics information obtained is providing a valuable base for verification of GCFR design and safety analyses.     

New minimal-capacitor low-sensitivity RC-active synthesis procedure

A new low-sensitivity RC-active synthesis procedure is described which can be considered as an alternative to that of Antoniou in that the new method retains all the attractive features of his method. Further, this method uses the minimum number of capacitors which is frequently desirable for integrated circuits.     

Glyceride Composition in Interesterified Fats

The positional distribution of acyl groups in interesterified fats obtained from a number of vegetable oil-mixtures was studied by the selective deacylation reaction of Pancreatic Lipase. In the case of randomised fats, there was almost equal distribution of fatty acids in the three positions, which indicated completeness of randomisation and destruction of the selective orientation of acyl groups present in natural fats. On the other hand, there was little or no change in positional distribution during directed interesterification. It was found that for natural and randomised fats, the glyceride compositions calculated from the Lipase hydrolysis data agreed quite well with those obtained by argentation thin-layer chromatography (TLC) followed by gas-liquid chromatography (GLC) with an internal standard. The glyceride compositions of directed interesterified fats, found by argentation TLC followed by GLC, indicated that the proportions of GS₃ and GU₃ increase to a considerable extent with simultaneous decrease in GSU₂, while that of GS₂U increases to a comparatively small extent, or remains unchanged.     

Conjugated hydrogenation of triglyceride oil containing conjugated acid

Conjugated hydrogenation of tung oil (fatty acid composition: elaeostearic 57.0%, linoleic 25.8%, oleic 11.2% and saturated 6.0%) has been investigated to ascertain the influence of hydrogen donors, namely primary and secondary alcohols, on rate and selectivity under different operating conditions. 2-Propanol, in general, reflects faster rate and greater degree of reduction but less selectivity towards the reduction of unsaturated acids than ethanol, when tung oil is treated at 200 C, 225 C and 250 C with 2% Ni (optimum catalyst level) and theoretical as well as 100% excess of theoretical amount of the two hydrogen donors to ensure complete hydrogenation of the oil. The rate and degree of reduction with ethanol are less influenced by its amount and amount of catalyst, but with 2-propanol these depend considerably on both the amount of hydrogen donor and amount of catalyst. During conjugated hydrogenation of tung oil, deposition of gel-like mass in minor amount occurs only at the wall of the reaction vessel. This is evidently due to polymerization of the conjugated trienoic acid. Presented at the IXth ISF Congress, Rotterdam, September 1968.     

Behavior of decomposition of rifampicin in the presence of isoniazid in the pH range 1-3

The extent of decomposition of rifampicin in the presence of isoniazid was determined in the pH range 1-3 at 37°C in 50 min, the mean stomach residence time. With increase in pH, the degradation initially increased from pH 1 to 2 and then decreased, resulting in a bell-shaped pH-decomposition profile. This showed that rifampicin degraded in the presence of isoniazid to a higher extent at pH 2, the maximum pH in the fasting condition, under which antituberculosis fixed-dose combination (FDC) products are administered. At this pH and in 50 min, rifampicin decomposed by ~ 34%, while the fall of isoniazid was 10%. The extent of decomposition for the two drugs was also determined in marketed formulations, and the values ranged between 13-35% and 4-11%, respectively. The extents of decomposition at stomach residence times of 15 min and 3 h were 11.94% and 62.57%, respectively, for rifampicin and 4.78% and 11.12%, respectively, for isoniazid. The results show that quite an extensive loss of rifampicin and isoniazid can occur as a result of interaction between them in fasting pH conditions. This emphasizes that antituberculosis FDC formulations, which contain both drugs, should be designed in a manner that the interaction of the two drugs is prevented when the formulations are administered on an empty stomach.     

Removal of lead from contaminated water bodies using sea nodule as an adsorbent

Adsorption of water soluble lead on polymetallic sea nodule has been studied in detail. Complete decontamination of lead is possible by appropriate sea nodule dosing. Adsorption is also dependent on pH and best adsorption is achieved at pH 6. Beyond pH 6, the desorption of lead from sea nodule surface is practically zero. Residual metal concentrations in the filtrate after adsorption is negligible. Both Freundlich and Langmuir isotherms may reasonably explain adsorption of lead on sea nodule. Chemically bound moisture plays a very crucial role in lead adsorption. Lead adsorptive capability of sea nodule is practically destroyed when calcined at a temperature of 900 degrees C. Lead loading capacity of sea nodule has been estimated at 440 mg of lead per gram of sea nodule. The performance of sea nodule as a lead adsorbent has been successfully tested over six simulated lead contaminated water systems. Lead loading capacity of sea nodule compares favorably with other adsorbents like activated carbon, ion exchange resin, anionic clay, granulated blast furnace slag and natural and treated zeolites.     

Modeling of the refractive index and extinction coefficient of binary composite films

Southwell's analysis of optical multilayers within the limits of very thin films has been extended to include absorption in the multilayer for predicting the effective values of the refractive index n(e) and extinction coefficient k(e) of mixed-composition binary homogeneous films over a wide spectral region, including the high-absorption (k > 10(-2)) region. It has been found that n(e) in general is a complicated function of the optical parameters (n(1), k(1), n(2), k(2)) and volume fractions (f(1), f(2)) of the component materials in a homogeneous layer, and the expression for n(e) becomes the same as that predicted by the Drude model in the spectral region where the layers are transparent. Moreover, according to the present analysis, the volume fractions of the product of the refractive index and the extinction coefficient of the component materials of a binary composite film are additive and the sum equals the product of the effective refractive index and extinction coefficient of the composite film.