[en] Phase transition study for four metallic glasses of Co-B series were undertaken. Differential Thermal Analysis (DTA) was performed up to a temperature of 1000 deg. C well above crystallization temperature or all the four alloys. Results were found in agreement with electrical resistivity. (author)

[en] Use of lichen as an environment pollution monitor has been emphasized for determination of inorganic impurities, a procedure for destruction of organic matter was adapted. The impurities were finally determined in the digest using ICP-AES and atomic absorption technique. Results on analysis of different samples have been presented and discussed. (author)

[en] Thermal analysis of solution precipitated blends of polystyrene PS and high density fluoro polymer copoly chlorotrifluoroethylene-vinylidene fluoride) poly (CTEE-VDF) has been carried out to study the transition behaviour. PS and poly (CTFE-VDF) were fund to be almost completely immiscible over the entire composition range studied. No significant glass transition depression due to blending was observed. (author)

[en] Pyrolysis GC method has been applied to investigate the structure and composition of polystyrene and the plastic wastes based on this polymer. The production of hydrocarbons and monomer of this polymeric system was monitored. The effect of variation of temperature (300-800 deg. C) sample size (1-10 mg), pyrolysis atmosphere (Nitrogen and Helium), residence tie (0.365-1.218 seconds) and catalyst (alumina, silica gel and zeolite) on the distribution of these prodicts were studied. (author)

[en] Acid hydrolysis of kallar grass (leptochloa fusca) was carried of with various concentrations of sulphuric acid, ortho phosphoric acid and hydrochloric acid to produce furfural. The study revealed that activity of various hydrolysing acids to produce furfural from kallar grass was of the following order H/sub 2/SO/sub 4/ > H/sub 3/PO/sub 4/ > HCl. Optimum yield (4.78%) of the produce was obtained when the material was digested with 19% H/sub 2/SO/sub 4/ for a period of 20 minutes. (author)

[en] The Fifth National Chemistry Conference was held at Quaid-i-Azam University, Islamabad by the Chemical Society of Pakistan from 25-28 October, 1993. In all 165 papers and 42 posters were presented in six sessions in the fields of analytical, inorganic, organic, physical, environmental, agriculture, theoretical and applied chemistry, biochemistry and biotechnology. The general standard of the papers was good. (A.B.)

[en] Iron, cadmium, aluminum and chromium could be easily determined by voltammetric methods. The chelation behaviour of chelating agents like hydroxyquinoline, NaDEDC, cupferron etc. have been investigated on the voltammetric behavior of these metals. The results were compared with the spectro fluorimetric investigation of these metal chelates and a relation between voltammetric and fluorimetric behaviour have been established. (author)

[en] Carrier distillation technique, helps to improve sensitivity of various elements by suppressing the profused spectra of the complex matrix. Determination of refractory elements was carried out by Carrier distillation technique, dc-arc Atomic Emission spectrography. An inert atmosphere was utilized in quartz glass chamber consisting of oxygen and argon gas at a constant flow rate. A number of carrier combination have been investigated. (author)

[en] More than 20 obligate methane utilizing bacteria were isolated from local soil following shake flask enrichment and continuous subculture technique isolation of methanotrophs proved to the difficult and slow. All isolates were gram negative, strictly aerobic, use methane as their sole carbon and energy source, unable to grow on nutrient media and can use nitrate as N source. Some isolates were motile. Few were able to utilize methanol. All the tested soil samples contained methane utilizing organisms. (author)

[en] Trace elements analysis in hair can be useful in studying the impact of environmental and dietary factors on human in general for lead and zinc content in hair. Samples of people of different age groups, sex with varied living habits of the individual living in different areas of Sind, urban as well as rural areas were of special interest to be studied to find correlation of socioeconomic factors and the presence of these elements in hair samples. The purpose of this study was to determine whether age, sex and physiological status and environmental pollution affect composition of hair. The method of sample preparation and use of atomic absorption techniques providing unequivocal and direct estimation of metals in ppm/ppb range to arrive upon conclusion. (author)