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Typha angustifolia is a metal hypertolerant grass that predominates the wetlands of uranium tailings in Jaduguda, India, contaminated with extreme levels of iron (Fe) and manganese (Mn). In the paper investigations were carried out to understand the molecular mechanism of metal tolerance in this tolerant macrophyte. Metal analysis was coupled with fluorescent differential display (FDD) and reverse northern to compare the metal profile and transcriptome between Typha plants growing in the tailings versus a control wetland. The expressions of the validated transcripts in Mn and Fe stress were confirmed using reverse northern and semiquantitaive RT-PCR. Typha selectively accumulated and stored Mn in shoots but excluded/restricted Fe both in the field and in vitro. Differential expressions of 23 ESTs were validated among 118 FDD genes. Although Typha behaved as a Mn accumulator, these transcripts were found to be regulated in a complex fashion not only by Mn accumulated in the shoots but also by Fe excluded from the shoots. Our results provide the first report in the molecular understanding of metal tolerance in Typha angustifolia and indicate a complex regulation of genes in response to metals in a contaminated habitat.

Delayed hydride cracking (DHC) is one of the localized forms of hydride embrittlement caused by hydrogen migration up the tensile stress gradient. In this work, DHC velocity was measured along the axial direction of the double melted, cold worked and stress-relieved zirconium-2.5niobium pressure tube material in the temperature range of 162-283 degreesC. The DHC crack growth was monitored using the direct current potential drop (DCPD) technique. The calibration curves between the normalized DCPD output and the normalized crack length at different test temperatures were also used to determine the DHC velocity. A simple model capable of explaining the observed features of DHC is proposed. The model explains the basis for the occurrence of incubation period associated with DHC crack initiation. Activation energy associated with the DHC in this alloy was found to be 56 kJ/mol. (C) 2002 .

In West Bengal, India arsenic in ground water has been found to be above the maximum permissible limit in seven districts covering an area of 37,493km2. In the present study, evaluation of the micronuclei (MN) formation in oral mucosa cells, urothelial cells and peripheral blood lymphocytes was carried out in the symptomatic individuals exposed to arsenic through drinking water. Forty five individuals with cutaneous signs of arsenicism from four affected districts (368.11 microg/l of As in drinking water) were considered as the exposed group and 21 healthy individuals with no symptoms of arsenic poisoning and residing in two unaffected districts (5.49 microg/l of As) were considered as controls. The exposed and control groups had similar age distribution and socioeconomic status. Standardised questionnaires were utilised and medical examination was conducted to ascertain exposure history, sociodemographic characteristics, diet, health, medication, addiction and chief symptoms in the study participants. Arsenic exposure was confirmed by measuring the arsenic content in the drinking water, nails, hair and urine samples from the volunteers. Arsenic contents in the urine, nail and hair in the exposed group were 24.45 microg/l, 12.58 and 6.97 microg/g, respectively which were significantly high in comparison to corresponding control group values of 4.88 microg/l, 0.51 and 0.34 microg/g, respectively. Exposed individuals showed a statistically significant increase in the frequency of MN in oral mucosa, urothelial cells and lymphocytes (5.15, 5.74 and 6.39/1000 cells, respectively) when compared with the controls (0.77, 0.56 and 0.53/1000 cells, respectively). Thus, the above results indicate that the symptomatic individuals exposed to arsenic through drinking water in this region have significant cytogenetic damage.

Abstract The paper deals with the findings of the laboratory investigations and field test on spontaneous ignition technique as a means of initiation of in-situ combustion process in the heavy oil field of Balol in India. The ignition delaytime observed in the field is compared with the values obtained during laboratory investigations and by an analytical approach. Introduction Ignition is the first step of in-situ combustion process. It can be achieved by heating the formation around the well bore with burner or electrical heater and then injecting air or simply injecting air and allowing the reservoir to ignite spontaneously. Certain crude oils, when exposed to air, will oxidize rapidly even at low temperature. This oxidation reaction releases heat and if the reaction rate is high enough to generate heat in excess of the heat loss, spontaneous ignition occurs. The time of spontaneous ignition can vary from a few days to several months and it depends on the initial formation temperature and the reactivity of the crude oil. In order to estimate the ignition time for a given reservoir, it is necessary to have a laboratory determined specific reaction rate. Laboratory investigations were carried out in Institute of Reservoir Studies(IRS) wayback in 1980's which ascertained the spontaneous ignition characteristics of Balol oil. In order to ascertain the viability of the process in the field, the test was initiated in Balol field in well IC#29 on March 10, 1995 and was continued till June 15, 1995. The main objective of the test was to ascertain the feasibility of this technique under field conditions and to find out the difference in ignition delay time between predicted and as observed in the field. Laboratory Investigations Laboratory investigations were carried out on Balol oil in early 80's at IRS to study the reaction kinetics and to find out ignition delay time. Experiments were carried out in a high pressure cell containing a small known quantity of sand oil mixture. The temperature of the cell was raised to reservoir temperature in an inert atmosphere to prevent premature oxidation. There after the inert gas was replaced by air at high pressure. After allowing sufficient time, depending on the temperature, the percentage of O2 utilized inside the cell was determined. The specific oxidation reaction rate i.e. the mass of oxygen consumed per unit time per unit mass of oil is related to the kinetic parameters -E/R and ko.pO2n. Kinetic parameters evaluated from the test are as follows: Activation energy term B i.e. (-E/R) = 15652.2 R (8695.65 K) Specific reaction rate at temperature (kopO2n) =7758.28 sec-1. From the kinetic parameters and the physical properties of the oil, ignition delay time, which is defined as the time required for temperature to exceed 200C at a particular point, was estimated. For Balol oil it is found to be in the range of 1.46 – 2.72 days. The estimation accounts for the change in porosity and does not account for the heat losses. Analytical Prediction Analytical calculations were done to predict the distance at which ignition occurs and ignition delay time and the change in injected O2 level with distance & time during spontaneous ignition. The methodology takes into account the reaction kinetics of the oil and heat transfer by conduction and convection. Arrhenius equation describing the reaction of air (oxygen) with oil or coke-like fuel is given by Oxygen depletion is then predicted by taking into account the reaction rate by following equation: P. 435^

Abstract In-situ combustion process was initiated in March, 1990 on a pilot scale in heavy oil field of Balol. Based on the success of the Pilot in terms of stabilised combustion and additional oil gain, the process was extended to a near by larger pattern in January, 1992. The main objectives were to observe the process performance in a larger area and to see the effect of placing the injector closer to downdip producers. The overall combustion performance of the project indicates that combustion can be initiated, sustained and propagated in reservoir like Balol and substantial oil gain can be achieved through proper monitoring of the process. The success of the project and the experienced gained through operating it, led to the decision of commercialisation of the process in the entire field. This paper deals with the performance of the in-situ combustion process at Pilot and extended scale, operational problems faced during implementation and the future strategy of commercialisation of the process. Introduction Oil and Natural Gas Corporation Limited (ONGC) initiated Pilot testing of in-situ combustion process in March, 1990 in the heavy oil field of Balol in North Gujarat, India. Interest in application of in-situ combustion process as an Enhanced Oil Recovery (EOR) tool was stimulated mostly due to the existence of large heavy oil reserves with low expected primary recovery. The encouraging results of the Pilot led to the extension of the process to an adjoining 9-hectare pattern in January, 1992. Presently combustion is in progress in both the patterns. Pilot Based on the laboratory findings, an inverted 5-spot pattern of 2.2 hectare was initiated on March 16, 1990. The Pilot has four producers (IC-2, IC-3, IC-4 & IC-5), one injector (IC-1) and one observation well (IC-6), 20 m away from injector and in line with IC-5. Figs. 1 & 2 show configuration of Pilot and location map of Balol field respectively. Table 1 shows petrophysical parameters of the Pilot area. The main objectives of the Pilot were:–To test whether combustion can be sustained and propagated.–To assess incremental oil recovery and Air-Oil Ratio.–To build-up and absorb the technology. Pilot Operation Ignition. Sand-face ignition was initiated by means of a gas burner. A total of 6.64 MM kcal (26.34 MM Btu) of heat was injected in a span of seven days during ignition operation. Air and water injection performance. Air & water injection profiles of the Pilot are shown in Figs. 3 & 4 respectively. Dry combustion phase lasted for 110 days after ignition period. Thereafter, the process was switched over to wet combustion phase. Air injection was increased in steps from 10,000 Nm3/d to 35,000 Nm3/d during dry combustion period. But due to subsequent rise in gas-liquid ratio in updip wells, air rate was reduced to 20,000 Nm3/d. Initially, during wet combustion phase, air and water were injected simultaneously at water-air ratio (WAR) of 0.002 m3/Nm3. It was switched over to cyclic injection in January, 1992. WAR was maintained, thereafter, at 0.001 m3/Nm3. A cycle consists of 6 days of air injection followed by one day of water injection. Since last week of February '96 water injection is being carried out through updip well IC-5 and air injection is being continued through IC-1. As on March 31, 1996 cumulative air and water injected were 32.81 MM Nm3 and 34,250 m3 respectively. P. 289^