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Superconducting phases in the Pb-BSCCO system have been produced by ethylenediaminetetraacetic acid (EDTA)-gel processing using nitrate solutions. The decomposition of EDT A-gd precursor has been studied by thermo-analytical techniques in conjunction with X-ray dilTraction (XRD) method. The thermo-analytical data are discussed in relation to the sequence of phase formation necessary for the production of superconducting phases. The effect of Pb is shown to lower the temperature of formation of the Bi2Sr2Ca2Cu3o,. (2223) high Tc phase. The Bi2Sr2Ca,Cu20y (2212) low Tc phase was observed as a main product at 800°C along with the Bi2Sr2Cu2o,. (220 I) phase and Ca2PbO •. Sintering at higher temperature (845°C) led to the formation of the high Tc phase (2223). 11 is shown that liquid phase sintering of the samples assisted the fomlation of the 2223 phase. There is an optimum level of Pb addition above which the 2223 phase is not produced even when heated for up to 60 hours at 845°C.read more
N ARSHAD ,M ARSHAD ,F R SALE ,A H QURESHI ,S K DURRANI ,S U REHMAN ,
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Effluent samples were collected from some of the marble industries located in the Industrial Estates of NWFP and were chemically evaluated for the panmeters like TSS, TDS, BOD, COD, and metl.lslike Cr+', Fe+2, Zn+2, Pb+2, eu+2 and Ni'2, These values were compared with the National Environment Quality Standards, (NEQS) and it wu found that most of the values are higher then the standard limit ofNEQS.The TSS values are in the range of 1915 to 2915 mwL for the samples collected from Industrial Estate Hayatabad. Its values ranges from 985·2219 mWL for Industrial Estate Hattar and from 675·2212 mwL for Industrial Estate Oadoon 525·1612 mWL (or G.T.Road and 8244010 mWL for scattered Industries. Similarly the TDS vallies ranges from 2617·2840 mWL for Industrial Estate Hayatabad, 2328·3955 mWL for Industrial Estate Hattar, 2140·3688 mWL for I.E. Oadoon, 1523·3880 mwL for G. T. Road and 1617·2280 niWL for scattered Industries. The COD values ranges from 50·75 mWL for Industrial Estate Hayatsbad, 96·160 mwL for Industrial Estate Hattar, 110-240 mWL for Industrial Estate Oadoon, 82·210 mwL for G.T:Road and 96·128 mWL for scattered Industries. The BOD values in almost all the samples of the Industrial Estates were found to be within the permissible limits of 43·59 mWL Trace toxic metl.ls were also found to be within the permissible range. however in some samples they exceed the NEQS read more
M KHAN ,IMAD ULLAH ,A R KHAN ,U KALSOOM ,F KHAN ,
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Vanadium(IV) fonns highly stable complexes with acetohydroxamate. In the detennination of thermodynamic parameters such as .6.G, MI and M; of these Vanadium (IV) complexes, the data was processed and analyzed by computer program BEST for the refinement of the calculated log p values. Graphs were plotted with Inp versus Iff, which gave .Mi/R as slope and .6.SIR as intercept Enthalpy change for Vanadium(IV) with this simple hydroxamic acid was found to be -166.0, -83.0 and -86.0kJ/mole for ML. , M~ and ML] respectively. Entropy change was 672.30, 475.38 and 567.12 J/mole for ML, M~ and ML] complexes respectively. While .6.G values calculated for these species were -372.3, -230.5 and -261.8 kJ/mole. The .6.S is most positive for a 1: I complex while .6.G and MI are more negative for the same. read more
K ALI ,N FATIMA ,Z T MAQSOOD ,
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Eight compounds including stigma sterol, oleanolic acid, ursolic acid, betuline, 2P, 3P-dihydroxyurs-12-en-28.oic acid, 2P, 3P, 23-trihydroxyurs-12-en-28-oic acid, 3P, 6«dihydroxylup-20(29)-ene and 6a-hydroxylup-20(29)-en-3p-octadecanoate have been isolated from Periploca aphylly their structures have been established with the help of spectral data.read more
A MALIK ,N RIAZ ,A U REHMAN ,H AHMAD ,Z AHMAD ,
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Effluent samples were collected from a sugar industry at Peshawar (Pakistan) in the sugar-cane season (Dee-March, 2002) and beat season (May-August 2002). The samples were chemically evaluated for different parameters. Total suspended solids (fSS), chemical oxygen demand (COD) and biological oxygen demand (BOD) values were found higher than the threshold limits and can therefore create aquatic problems in the Kabul River. A treatment process (mainly physicochemical) has been developed to reduce the harmful effects of the sugar mills effluent and to safeguard the aquatic habitat of the Kabul River. The efficiency of the treatment process in terms of BOD and COD reduction was found to be 96% and 95% respectively, which signifies its suitability to be used as an appropriate process. The process has the potential to protect the water bodies from further deterioration. read more
M KHAN ,A R KHAN ,U KALSOOM ,T MAHMOOD ,M RIAZ ,
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The biological and Physiological activities exhibited by various species of Astragalus have created wide interest in its phytochemistry. This article describes the flavonoids reported from the genus Astragalus up to 2000.read more
G A KHAN ,I R KHAN ,A R KHAN ,M N KHAN ,H KHAN ,
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Solvent effect on 13C chemical shifts of 6-methylquinoline and 8-Methylquinoline has been studied in eight different solvents. 13C chemical shifts of these compounds have been measured in 30% (v/v) solution using DMSO-~ as an internal locking agent and Hexamethyldisiloxane (HMDSO) as an external reference. Carbon tetrachloride (CCL,) has been taken as a reference compound for comparison of these shifts because this is non polar. The purpose of the present study is to see the solvent effects of various solvents in the light of Buckingham, Schaefer and Schneider (BSS) theory. Present study has shown that polar solvents like chloroform, dimethylsulphoxide, acetone, methanol and ethanol, show positive deviation from CCL" while benzene show negative deviation. More negative shifts behavior at C8, C9 and CIO carbon atoms in these compounds is due to neighboring nitrogen atom whose lone pair of electron causes this change. C2 carbon atom shifts are also affected by nitrogen atom. Benzene shows negative shifts and entirely different behavior because of 1t-bonding and ring current phenomenon. Cyclohexane is a non-polar compound and it shows negative behaviour, because it has low dielectric constant compared to carbon tetrachloride.The present study on solvent dependent I3C chemical shifts has been done at a frequency of 22.50 MHz using JEOL FX-90Q IT NMR.read more
M H PHULPOTO ,A R SOLANGI ,A W K KHANZADA ,S A PATHAN ,
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We have been interested in the synthesis of hydro gels with fast swel1ing kinetics and supersorbent properties. So copolymer of NIP A and AA was prepared using bis as cross linker and TEMED as activator. The copolymer was characterized by determining the swelling ratio in aqueous solution as function of time, ionic strength, temperature, concentration of monomer and cross linker and best concentration for them is reported. The resultant chemically cross linked networks show levels of swell ability in water significantly higher than those previously reported for such copolymer using.read more
S ZAKIR ,B AHMAD ,S BASHIR ,Z IQBAL ,M NISAR ,
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The role of elements particularly trace elements in health and disease is well established. In this paper the authors investigate the presence of various elements in very impor1ant herb Aloe barbadensis (Aloe vera), it is commonly used in different ailments especially of elementary tract and skin problems. Four acid digestion methods for the determination of total elements in Aloe barbadensis were made. The samples of the plant were collected from surrounding of Hyderabad city, Sindh University, Jamshoro and vouchers specimens were prepared following the standard herbarium techniques. In total fifteen essential, trace and toxic elements such as Zo, Cr, K, Mg, Ca, Na, Cu, Fe, Pb, AI, Ba, Mil, Co, Ni, and Cd were determined in the plant, and in its decoction, using Atomic absorption spectrophotometer Hitachi Model 180-50. The procedure found to be more efficient than other methods of decomposes the biological material in nitric acid and 30% hydrogen peroxide. The validation of the methods was checked with the NBS-I570 (Spanish) as standard reference material. The yielded element values were in close agreement with certified values. The percentage recovery of different elements was found to be better i.e. (98-99%) as compared to other method of digestion. It was noted that level of essential elements was high as compared to the level of toxic elements read more
Q SHAIKH ,T G KAZI ,M A JAKHRANI ,S R SAHITO ,M A MEMON ,G Q SHAR ,G H KAZI ,
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Comparative study of important macro and micronutrient elements between two varieties of rice, i.e. Kashmir Nafis and NIAB IRRI-99 as well as its soil have been carried out using Atomic Absorption Spectrometry. Maximum concentration (mglkg) of macro-elements Na and K were found in Kashmir Nafis rice variety (i.e. 478, 3668) respectively, whereas highest concentration (2542) of Mg was found in NIAB IRRI-99 rice variety. Highest amount (mglkg) of micro-elements Zo, Mo, and Cu were found in NIAB IRRI-99 rice variety (i.e. 43.09, 56.31and 6.48) respectively, while the highest concentration of Fe and Ca (1043 and 77.68) respectively, were found in Kashmir Nafis rice variety. Maximum concentration (mglkg) of AI and Ba were found in NIAB IRRI-99 rice variety (i.e. 17.02 and 5.77) respectively. The high level (mglkg) of Cd, Cr and Ni were found (i.e. 0.392, 1.01 and 1.90) in Kashmir Nafis rice variety and the maximum concentration of Co and Pb were found (i.e. 4.70 and 1.20) respectively in NIAB IRRI-99 rice variety. The concentrations (mglkg) of the soil was determined for Na, K, Ca, Mg, Zn, Fe, Mn, Cu, AI, Ba, Ni, Pb, Co, Cd and Cr (3284, 2457, 3204, 41519, 91, 5731, 536, 25.65, 35964, 111, 16.66, 5.64, 13.52, 1.95 and 13.63) respectively from the same place where both varieties were grown. read more
G Q SHAR ,T G KAZI ,S R SAHITO ,Q HAQUE ,
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