VOLUME 25, NO4, DEC 2003

Differential Thermal Analysis of Lignite Coals/Mineral Mixtures and Decomposition Studies of Carbonate Minerals in Coal Ashes by Isothermal Thermogravimetry

In the present work, the rates of decomposition for Siderite and Magnesite minerals found in lignite ashes have been evaluated by isothermal thermogravimetry by monitoring the weight loss for 60 min at 350°C, 400 "C, 500 °C and 575°C and the mineralogical composition of coal ash was evaluated .The comparative account is also given for DTA of coal/mineral mixtures in air atmospheres which show the major exothermic effects in the initial and final temperature zones of major peak configurations. read more

---

A G M VASANDANI ,M I BHANGER ,G M KUMBHAR ,S W SHAH ,

Changes in the Quality of Sunflower and Soybean Oils Induced by High Doses of Gamma Radiations

The effect of gamma radiations of different doses on the quality of edible oils such as Sunflower and Soybean oils were studied w. r. t. the changes in the Peroxide Value, Free Falty Acid, Iodine Value, Carotene, Anisidine Value, Refractive Index and Color. The oil samples were radiated with gamma rays using Cobalt-60 source at the rate of 0.9234 kGylh, with doses of 1,5, 10, 15 and 20 kGy. The non-radiated Sunflower and Soybean oils were used as a control. The results show that the Peroxide, Free Falty Acids, Anisidine values and Optical Density levels increase and Iodine, p-Carotene levels decrease with the high doses of radiation. It was found that the Soybean oil is more resistant to radiations as compared to the Sunflower oil.read more

---

G LUTFULLAH ,T AHMAD ,F K BANGASH ,S ATTA ,A ZEB ,

Micellar Effect of Anionic, Cationic and Nonionic Surfactants on Electron Transfer Process of Methylviologen Measured by UV -Visible Spectroscopy

The reductive electrochemistry of methyl viologen (My2+) was surveyed in the presence of sodium dodecyle sulfate (SOS), sodium dodecyl benzene sulfonate (SOBS), Dodecyl ethyl dimethyl ammonium bromide (OEOAB) and Sorbitane rnonolaurate (SPAN 20) micelles, by considering the UV -visible technique. The effect of different surfactants on the reduction of methyl voilogen radical was studied by using the UV-visible technique. The possible interactions of the anionic, cationic and nonionic surfactants with the reduced methyl voilogen in the miceller and premicellar phase were discussed. In a definite range of concentration it was suggested that MY'+(MethyJ voilogen radical) resides ,\!articularly in non­'aqueous environment, such as miceller hydrocarbon core, Detection of MY' in the presence of anionic surfactant is possible through the peak heights of the UV -visible spectra, while in case of cationic and non-ionics, no observable changes occurred in the premicellar as well as in micellar concentrations.read more

---

M Y K NAZIR ,S S SHAH ,S AMIN ,

Micronutrients Status and Phosphate-fractions , in Chitral District Agricultural Soil

Micronutrients and phosphorus has been identified as a major factors involved in increasing the agricultural soil fertility. The soil samples from agricultural fields of Chitral District were collected and analyzed for various micronutrients like Cu+2, Zn+2, Mn+2,. Fe+), Na+, Li+, Cd+2, Pb +3, total phosphate and phosphate fractions such as AI-phosphate, Fe­phosphate, Ca-phosphate, Fe-phosphate (occluded), AI-phosphate . (occluded) and water­soluble phosphate. The results show adequate amount of micronutrients except lithium, in the samples phosphate-fractions distribution were found in the order of Ca-Phosphate > Fe­Phosphate> AI-Phosphate. Their impacts on soil properties and plant growth have also been discussed.read more

---

S ALAM ,F K BANGASH ,R AFZAL ,

Vat Leaching of Bulk Mineral Matter from Some Pakistani Coals Effect of Leachant Concentration

Effect of leachant concentration on mineral depletion in some Pakistani coals was studied varying the concentration of leachants i.e. Ammonium acetate, HCI, HNO) and HCI folIowed by HF folIowed by HC\. The extracts as welI as the residual coal samples were analyzed for inorganic elements i.e. Fe, K, Na and Ca+Mg (combined). Amongst the metals studied, Fe and Ca+Mg have been extracted significantly compared with the extraction of Na and K. Complete mineral depletion in any case was not achieved even when extraction was performed with high concentration of either of the leachants. Leachability of some metals has been found concentration dependent while other exhibited deviation.read more

---

I AHMAD ,M A KHAN ,M SHAKIR ULLAH ,M ISHAQ ,

Characterization of Ceramic-reinforced Epoxy-based Composite Materials

Composite materials based on 2,2-bis (p-2-hydroxy-3-methacryloxpropoxy phenyl) propane (HMAPP) for different applications have been studied. Diametrical tensile strength (DTS), compressive strength (CS) and Vickers micro-hardness (VMH) have been found to decrease with increasing diluent concentration and decreasing filler concentration. Exotherm during setting was found to decrease sharply with increase in filler content for quartz and silica filled composites. Water sorption studies indicate that the amount of water contents are relatively higher for the quartz filler as compared to silica filler. Comparison of mechanical properties show quartz to be better filler than silica for the given formulations studied. The effect of acid and/or heat treatment for quartz filler on the DTS and CS of the final composite have also been studied; the two treatments improved the aesthetic appearance of the composite.read more

---

S ZULFIQAR ,A QUDDOS ,A WADOOD ,M L MIRZA ,M SHAHID ,

The effect of Crosslinking Agents on the Synthesis and Swelling of the Polymer Networks

Polymer networks of 2-Hydroxyethyl methacrylate (HEMA) and N­Hydroxymethyl acrylamide (HMA) were prepared by varying the amount of the Ethylene dimethacrylate (EDMA) and N, N-Methylene diacrylamide (MDA) as crosslinking agents. These Polymer networks have the glassy behavior in dry state, with elasticity when they absorb certain amount of water. In both cases, the material behavior is influenced, to great extent, by the network prepared, i.e., by crosslinking reaction. It is known that the netwprk characteristics (crosslink density, etc.) are influenced not only by the concentration of crosslinking agent, but also by its chemical structure. By varying the amount of crosslinking agents and equimolar ratio of the monomers, a wide range of networks were synthesized and the influence of the temperature and crosslinking on their swelling is discussed. A correlation between swelling data, derived from loosely crosslinked samples, led to the determination of the interaction parameters of strongly crosslinked polymer networks of series I and II has been describedread more

---

A WADOOD ,S ZULFIQAR ,H U REHAMAN ,A QUDDOS ,M L MIRZA ,

A Mathematical Relationship between the Sodium and Aluminium Oxide Concentrations of Aluminate Solution Samples

The objective of the present study was to investigate the correlation between the sodium and aluminium oxide concentrations of aluminate solution samples from Seydi~ehir, Turkey. The ultimate purpose of this paper is to find a mathematical relationship between the dimensionless concentration ratios of aluminium and sodium oxides. For thjs purpose, the observed aluminium oxide concentrations were used to generate an empirical relationship: A, =1.013 . A2 . N,·o.284 . N2o.284 where, A, is the aluminium oxide concentrations (gIl), A2 is the mean aluminium oxide concentrations, Nt is the sodium oxide concentration (g/l) and N2 is the mean sodium oxide concentration. A plot of Ln (A,/A2) versus Ln (NtIN2) as nondimensional variables gave a straight line for the present system. Such an empirical relationship facilitates the estimation of aluminium oxide concentrations from the sodium oxide concentrations measurements.  read more

---

S SAHIN ,

Antibacterial Co(II) Complexes of Benzothiazole-Derived Compounds

Reaction of 2-acetamidobenzaldehyde with 2-amin0-4-methoxy-, 2-amino-4­chloro-, 2-amino-6-nitro- and 2-amino-6-methylsulfonyl benzothiazole afforded a series of congeners which have been further used for complexation reaction to obtain potential Co(II) compounds. The title compounds of the type [M(L)21x", where M=Co(II), L=L'-L4 of Fig.l, X=N03', 80/', C20/' or CH3C02' and n=1 or 2, have been characterized by physical, spectral, an.d analytical data. The compounds act tridentately and their metal (II) complexes are proposed to possess an ,octahedral geometry about the central metal atom. These compounds in comparison to their metal complexes have been screened for antibacterial properties against the pathogenic species Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa.read more

---

Z H CHOHAN ,H PERVEZ ,C T SUPURAN ,A SCOZZAFAVA ,

Trace Metal Contents in Selected Marine Fish Species of Northwest Coastal Area of Karachi, Pakistan

Levels of trace metals in edible mussels of five fish samples Pampus Argenteus. Pampus chinensis. Parastromateus niger, Protonibea diacanthus, and Otolithes ruber. of northwest costal area of Karachi were studied by AAS technique. All estimation were made on wet basis. Iron was found maximum(0.890-9.395Ilg/g) amont all species and cadmium was found as minimum (0.015-0.041 Ilg/g). Levels of other metals varied in the range of 0.249­0.986,0.137-0.49,0.29-0.929,0.391-0.986 and 0.081-0.243 Ilg/g for As, Co, Cu, Mn & Pb respectively in the muscles of various fishes investigated. Maximum concentrations of all metals were found in Protonibea diacanthus except Cd, which was found maximum in Parastromateus niger, and pampus argenteus was found lo contain the minimum amount of all metals. Various fish contain different concentration of all metals.read more

---

R SIDDIQI ,R RAZA ,S NAZ ,S A SAYEED ,