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Abstract  

Coupled TG-FTIR technique was used for identification of gaseous compounds evolved at thermal treatment of six coal samples from different deposits (Bulgaria, Russia, Ukraine). The experiments were carried out under dynamic heating conditions up to 900C at heating rates of 5, 10 or 50 K min–1 in a stream of dry air. The emission of CO2, H2O, CO, SO2, COS, methane, methanol, formic acid, formaldehyde, acetaldehyde, chlorobenzene was clearly identified in FTIR spectra of the samples studied. The formation of ethanol, ethane, ethylene and p-xylene, at least on the level of traces, was also identified. At the heating rate of 5C min–1 the temperature of maximum intensities of the characteristic peaks of COS was 270C, of formaldehyde, formic acid, ethane and methanol 330C, of SO2, CO, acetic acid, ethylene and p-xylene 400C and of chlorobenzene 500C. At 10C min–1 and 50C min–1 these temperatures were shifted, respectively, by 70–300C and 150–450C towards higher temperatures and the respective absorption bands in FTIR spectra were, as a rule, more intensive.

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The influence of preliminary annealing (at 400 and 1000 °C) and wet treatment (with 0.1M HCl; with 0.1M NaOH) of aluminum oxide on the separation efficiency of 68Ge-68Ga radionuclide chain was studied. The adsorption behavior of 68Ga daughter radionuclide was examined by desorption in order to find the best conditions for separation of both radionuclides. The effect of the preliminary annealing and wet treatment of alumina on the experimental generator columns was studied.

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Abstract  

Chemical treatment assumes an important role in the management of radioactive wastes as it is a simple technique and offers advantage in terms of handling of wastes thereby reducing the risk of mansievert exposure. Low level wastes (LLW) and intermediate level wastes (ILW) are generated in various facets of nuclear fuel cycle and have various chemical composition. A systematic study was carried out by using copper ferrocyanide and calcium phosphate precipitation methods for the removal of cesium and strontium, respectively. The supernatants were subjected to ultra filtration (UF) using a membrane having a pore size of 0.2 m. The decontamination factors (DF) at 2 and 24-hour intervals with and without UF were estimated. The DF obtained was in the range of 200–300 for cesium and 200 for strontium with LLW solution which has chemical characteristics similar to ground water. Two hours of settling is adequate for strontium before UF. In case of cesium there is no much change in the DF values by UF. However, the UF has helped in the solid — liquid separation as the flocks of copper ferrocyanide precipitate are feathery in nature. The effect of ionic strength and the presence of TBP on the removal efficiency of cesium and strontium have also been studied. DF are observed to be a function of ionic strength and are low in deionized water, in salt solutions containing 1 to 4M sodium nitrate and also in solutions of ILW. However, increasing the chemical dosing to two times of normal plant dosing has yielded a DF of about 200 for sodium nitrate solutions with respect to cesium removal. When the concentration of ammonium nitrate in the waste exceeds 0.1M, the DF reduces. Entrained TBP as well as soluble TBP reduces the removal efficiency of cesium. This paper deals with the experimental data and mechanism of the processes involved in the removal of cesium and strontium.

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Phase changes of iron containing solid wastes from steel mill pickling lines after thermal treatments were investigated aiming the determination of the appropriate conditions for its transformation to be useful for industrial raw materials. Above 275°C, the thermally treated wastes contain a mixture of α-Fe2O3 (hematite) and γ-Fe2O3 (maghemite) in different proportions, depending on the maximum heating temperature of the thermal treatment. Increasing the maximum temperature the maghemite participation is decreased through its transformation to hematite. Above 850°C hematite is the main constituent, suggesting that thermal treatment of the wastes in this temperature will give a product that could be used as red iron pigment.

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steps of heat treatments of PS at different atmospheres: — First, PS is annealed in hydrogen at the temperature of 450° C for 15 min to desorb the porous silicon, then we change the temperature at 950° C and we let it for 2 h to simulate the step of

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The effect of various temperature treatments on TL response characteristics of CaSO4: Dy has been investigated for its reusability when the phosphor has been previously irradiated to increasingly higher gamma doses. In practice, annealing at a standard temperature, namely 400 °C, usually precedes the use or reuse of the phosphor. However, the study demonstrates that the phosphor with a previous history of high accumulated doses does not completely retain its original TL response characteristics with 400 °C treatment unless the phosphor is treated at an elevated temperature, namely 650 °C.

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Thermal analysis was used to deduce the mechanism of resistance to enzymatic digestion by starches and to account for the extent of resistance at different enzymolysis reaction temperatures. Thermalanalysis was also used to determine the most productive treatment temperature for exploration of the effects of heat-moisture treatment of starches on their subsequent chemical and physical behavior, including enzyme digestibility. The starches were selected according to an experimental design based on a nontraditional description of genetically varied corn starches. As a result, each functional response to heat moisture treatments of the starches adjusted to different moisture contents could be assigned to the relevant causative structural factor in the experimental design.

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Abstract  

Surface treatment on non-ferrous metals are proposed in order to minimize or determine quantitatively the interference of gaseous contamination. These proposals result from a large number of determinations of superficial contamination on several materials using microanalysis by nuclear reactions. This work is included in a larger program which aims the certification of standard materials in their oxygen, nitrogen and carbon contents.

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The proposal of this work was to investigate the effect of the radioactive (NH3)2PtCl2, cis-diamminedichloroplatinum (II) or CDDP* on malignant glioma cells and verify if the low-dose continuous internal radio-chemotherapy would be able to produce additive effects. The antitumoral activity of CDDP* and the non labeled cisplatin, CDDP, were evaluated in glioblastoma. Cisplatin was cytotoxic for glioblastoma cells in a dose dependent manner. Treatment with CDDP*, (IC50 = 1.75 ± 0.07 μM), proved to be more potent than using just CDDP, (IC50 = 4.96 ± 0.40 μM). These results suggest that cisplatin is a very potent radiosensitizer evoking a supra additive effect. Internal radio-chemotherapy treatment based on CDDP* may be useful alternative to reduce the drug concentration required for effective inhibition of glioblastoma growth.

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In-vivo neutron activation analysis (IVNAA) has been used in this laboratory, approximately for the past twenty years, to determine the bone status of humans. For this purpose, the total body calcium (TBCa) is assayed and that is indicative of the bone mineral concentration of the individual. We have effectively used this method to diagnose, understand and monitor the treatment of osteoporosis among elderly women, particularly in post-menopausal women. This paper summarizes the technique and our experience in dealing with osteoporosis.

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