VOLUME 26, NO1, MAR 2004

Manufacture of Synthesis Wollastonite

Synthetic wollastonite a calcium silicate has received much attention over the last decade. It is largely chemically inert and biologically safe. Due to its immense properties, the production capacity has increased substantially in recent years. Synthesis of wollastonite was investigated with regard to optimum parameters at laboratory scale; such as mesh size of raw material, (calcium carbonate, silica) time duration, sintering temperature, stoicheiometric ratio and characterization of product. It was found that wollastonite may be synthesized at maximum degree with varying sets of parameters. The maximum yield of the product with ratio 26: 15 for one hour was suitable to produce commercially acceptable product which is economically feasible. read more

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M AURANGZEB ,F M Z KAIFI ,M KHAN ,B AHMED ,

Measurement of Viscosity and Ion-solvent Interactions (B-Coefficient) from 20 To 50°C for Aqueous Electrolytes of Na+, K+ Mg++, Ca++ and Sr++

Viscosities of aqueous solutions of nitrates ofNa+, K" Mg++, Ca++ and Sr++ were determined by using a thermostated Ubbelohde flow, viscometer in the range of concentrations and temperatures from 20 to SO°c. From the experimental results; lon-Solvent interaction terms (P-Coefficients) were calculated in the concentration range 0.1 to 4M, by using an empirical equation of the form: 11 = 80 exp (hoM + CoM'). It was concluded that the viscosities of these ions in aqueous solutions could be understood in terms of hydration number, charge on the ion and the ionic radius. Ratio of the viscosities of the nitrates and chlorides with common cations were also calculated and interpreted in terms of hydration of cations, anions and ion pair formation. read more

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M A RAZI ,A MUMTAZ ,E A MUKHTAR ,S S SHAH ,H AHMAD ,Y KHAN ,

Comparison of Catalytic Activity of Clays on Locally Available Petroleum Fractions

The purpose of the present work is to explore the catalytic activity of locally available clays in petroleum fractions. The chemical analysis indicated mainly the presence of alumino-silicate dominance in the clay mineral composition. The major, minor and trace elements in clays were determined by employing X-ray Fluorescence (WD) and the mineral nature of clays were determined by IR spectroscopy. UVNisible spectrometry was employed to observe the concentration of naphthalene and benzene in gasoline of premium and naphtha brand. Clay sample no I and 2 showed the maximum catalytic reforming, whereas, sample no 4, 7 and 10 showed the maximum catalytic cracking. Sample no. 3, 5, 6, 8, and 9 showed no appreciable catalytic activity. read more

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M J IQBAL ,S MANZOOR ,M IKRAM ,M A RAUF ,

Strength Enhancement of Portland Cement Part-I: Pozzolanas as Partial Replacement for the Portland Cement

This paper presents the production of blended cement, based on the intergrinding of Portland cement and pozzolanic materials such as phyllite. slate, and shale. Portland cement was replaced with pozzolana upto 25% and the effect on compressive strength and other properties were studied. Maximum compressive strength of II ~ 150 PSI as compared to 5,800 PSI of ordinary Portland cement was obtained. Mortar (1:3 ratIo) based on hIgh performance cement demonstrated good strength (upto 5,400 PSI) as compared to 4,350 PSI ofOPC. read more

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M FAISAL ,M Z CHUGHTAI ,S A KHAN ,

Manganese Contents in Fruits and Soils in Elazig- Turkey Region

Manganese concentrations in fruit samples were determined by using flame atomic absorption spectrometry (FAAS). To identify the Mn phases most responsible for fruit­available Mn, the soil samples near the fruit plants were also analyzed for Mn by using various digestion and selective extraction reagents. The relation between the fruit-Mn levels and the Mn concentrations in soil extracts was studied. Total Mn concentrations determined in the studied soils and fruits were found in the range of 330 to 1100 and 1.6 to 22 mg/kg, respectively. The negative interferences were observed from Ca, Mg and AI at the higher concentrations than the their concentrations at the measurement step. It was observed that the Mn concentratIOns of mulberry samples correlate to the manganese concentrations of the cold citric acid extracts of soilsread more

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Y DILGIN ,M FAISAL ,M YAMAN ,

Dissociation Constant Studies of Lactic Acid at Different Temperatures and in Mixed organic - water Solvent Systems

Dissociation constants of lactic acid (2-hydroxy propionic acid) have been studied at different temperatures between 25 to 50·e interval in aqueous media and in mixed organic­water solvent systems (dioxane-water, ethanol-water and methanol-water) at 25·e. Potentiometric data was analysed for calculation of pKa values of monobasic acids. Results shows that pKa values are higher in mixed solvents as compare to in aqueous media. Significant effect of temperature and solvent's nature on pKa values has been observed. read more

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A W K KHANZADA ,SAEED UDDIN ,

Flow Injection Determination of Heparin by Inhibition of Ribonuclease (Rnase)

Heparin is a mucopolysaccharide from mammalian tissues. It is an anticoagulant drug used universally. Of naturally occurring mucopolysaccharides only heparin competitively inhibit Ribonuclease (RNase) in its physiological range. Because of high bleeding risks due to the continuous consumption of heparin its determination in blood is critical. Many assays have been devised to measure this substance in blood. This paper describes manual and flow injection methods for the determination of heparin by the inhibition of ribonuclease. Manual spectrophotometric method was found very simple and sensitive. By ihis method heparin can be determined in its physiological range. Calibration graph was linear in the range 1.0-16 llg mI·'. The limit of detection was 1.0 llg mI·'. However, sensitivity decreased in flow injection method while using immobilised Rnase. read more

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T GHOUS ,

Acid-base Equilibria of Succinic and Tartaric Acid in Binary Organic - water Solvent Systems

Ionization constants of two overlapping dibasic acids, succinic acid (butandioic acid) and tartaric acid (2,3-dihydroxybutandioic acid) have been studied at different temperatures between 25 to 50·C and in mixed organic-water solvent mixtures (dioxane-water, ethanol-water and methanol-water). Both succinic ad tartaric acids are symmetrical dicarboxylic acids with the same length of carbon chain but are markedly different in ionic behaviour at different temperatures and in all solvent systems. The effect of temperature on the thermodynamic parameters were calculated and interpreted.  read more

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SAEED UDDIN ,A W K KHANZADA ,

Salting-out Coefficients and Activity Coefficients of Alkali and Alkaline Earth Metals in Aqueous and Aqueous Organic Mixed Solvents

The effect of added electrolytes on the salting-out coefficients has been studied at 278± I K in aqueous and aqueous organic mixed solvents. The salting-out coefficients and corresponding activity coefficients for the various systems have also been studied. Thermo­dynamic parameters i.e free energy(tl.F) is also calculated. read more

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K MUZAFFAR ,S TASLEEM ,M ANWAR ,S DURRANI ,M NIAZ ,

Spectrophotometric Studies of Spermine Isolated from the Nutmeg of Myristicafragrans

The seeds of Myristica fragrans (Myristicaceae) were studied for spermine. The fruit kernels (nutmegs) were subjected to chloroform extraction. Spermine was isolated by TLC using different solvent systems and flow injection micro column. Spermine acid adduct was prepared for quantitative determination of spermine. Absorbance was noted in visible region on spectrophotometer. Spermine was found to be 0.0051 % in fruit kernels of M. fragrans.  read more

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A B JASRA ,S A RANA ,A MAHMOOD ,M N KHAN ,