m. ghannadi maragheh

To produce the Technetium-99 isotope from Molybdenum-99 radioactive decay and purify the product of small-scale acidic target dissolution, the gaseous Iodine impurity has to be reduced to AN acceptable level. Solid adsorbents are used for this reason. One of the best adsorbents is based on Silver-Exchanged Mordenite. In this research, the synthesis procedure and characteristics of synthesized adsorbent have been discussed. To prepare solid adsorbent, spheric mordenite hallow crystals of about 10 micrometers and the Si/Al ratio of 5.2 were synthesized and granulated using a binding agent, stabilizer, and foaming agent. Prepared granules were silver exchanged. The silver content of the end product was evaluated 8.1 weight percent. Results from gaseous Iodine adsorption showed that 99.2 percent of passing Iodine was adsorbed.

The present research investigates the feasibility of producing the radionuclide Lutetium-177 (177Lu) at the Tehran research reactor, TRR. 177Lu, with suitable nuclear decay characteristics and good chemical behavior, is an ideal therapeutic radionuclide. Some 177Lu-containing radiopharmaceuticals are currently applied in the treatment of various cancers, and many are under development and being tested in clinical trials in Iran. The radionuclide 177Lu can be produced either directly by the 176Lu (n,γ)177Lu reaction or indirectly by the  reaction. The irradiation yield of 177Lu in both production routes was experimentally determined for 14 days at a thermal neutron flux of 5×1013 cm-2.s-1 and was compared with the theoretical calculations. The effects of higher neutron fluxes and a reduction in 176Yb-enrichment-percentage on the produced activity/specific activity variations were assessed theoretically using MATLAB software. It was found that higher neutron fluxes led to higher activity. However, it does not impact specific activity fall rates two weeks after the end of the bombardment. In addition, a lower enrichment percentage of the target material utilized in the indirect method leads to a faster specific activity fall two weeks after the end of the bombardment.

Tc-99m is the most important nuclear medicine radioisotope produced from the decay of Mo-99. Currently, Iran's demand for Mo-99 is 120 Ci per week. More than 90% of the Mo-99 in the world is produced via U-235 fission. The supply chain of this radioisotope includes the Uranium target supplier, the nuclear reactor, the Mo-99 processing facility, and the Mo-99/Tc-99m generator manufacturer. Investigation of the domestic existing facilities of Iran shows that its production is feasible inside the country. The present study focuses on the Mo-99 production chain in Iran and presents the appropriate radiochemical method. Uranium targets in the miniplate form with irradiation capability in TRR were accepted as feed for processing unit facilities. According to the special limitations of Iran, the Modified AMOR process, which is a combination of AMOR and ROMOL processes, is identified as the appropriate method for the available U3O8-Al/Al targets. The researches and the experimental activities are proposed based on this method.

In this study, the removal of Zr (IV) from aqueous solutions was investigated using magnetic Fe3O4@PEG@TBP nanoparticles as a new adsorbent. Experiments were conducted to study the effects of initial pH, amount of adsorbent, shaking time, and initial Zr (IV) concentrations on zirconium sorption efficiency. The sorption of zirconium on Fe3O4@PEG@TBP nanoparticles was pH-dependent, and the optimal pH was 6.0. In kinetics studies, the sorption equilibrium was reached within 10 min, and the experimental data were well fitted by the pseudo-second-order model, and the equilibrium sorption capacities calculated by the model were almost the same as those determined by experiments. The maximum zirconium sorption capacity onto magnetic nanoparticles was estimated to be about 50 mg/g at 25 °C. Sodium acetate, sodium nitrate, sodium fluoride, and ammonium oxalate were used as desorbing agents. The highest values of zirconium desorption (100 %) was achieved using 0.5 M sodium fluoride as the desorbing agent. The present study suggested that this method is simple, fast, and highly efficient for zirconium removal from aqueous solutions by using magnetic nanoparticles.

In this study, recovery of uranium from leach liquor using solvent extraction technique in a horizontal pulsed sieve plate column was experimentally investigated. Extraction of uranium from an aqueous sulfate solution with 0.25M concentration acid, by using TOA solvent, diluted in kerosene and n-decanol modifier of 5%, 90% and 5% v/v respectively was studied and the influences of operation parameters including the phase flow rates along with pulsation intensity on the dispersed phase holdup, drop size and drop size distribution, as well as extraction efficiency, were evaluated. Increasing pulsation intensity along with the dispersed phase flow rate and decreasing the continuous phase flow rate caused to increase the extraction efficiency. Results showed that the horizontal pulsed sieve plate column has high efficiency for extraction of the uranium from leach liquor. Moreover, a comparative evaluation of available correlations proposed for the prediction of mean drop size and hold up in such columns have been conducted. New correlations for estimating mean drop size and hold up in a horizontal pulsed sieve-plate column were presented, which provided AARE of 7.7% and 8.2%, respectively.

The peptides radiolabeled with 177Lu are including a wide range of promising radiopharmaceuticals. The NCA form of 177Lu provides a high specific activity that is required in targeted receptor therapy in order to avoid saturation of the targeted receptors. In this study, the outstanding quality of NCA radionuclides especially in the case of 177Lu was evaluated by comparing with CA radionuclide for radiolabeling of DOTATATE peptide and. The NCA 177Lu and CA 177Lu were obtained by chromatography separation of irradiated 176Yb (enrichment: 96.4%) and irradiation of 176Lu (enrichment: 95%) respectively. Radiolabeling of DOTATE with CA and NCA 177Lu was carried out in the same conditions and time. Then, radiolabeling yield was calculated as a function of some parameters like the Ligand: metal ratio and stability of compound after production. The results showed the superiority of NCA 177Lu with respect to CA 177Lu. Not only the particle ratio showed the advantages of the NCA radionuclide, but also the long-term comparison over a period of 14 days revealed the inferior character of CA.177Lu with regard to the high requirements regarding the specific activity set by radio-immunotherapy.

Pulse oximetry is a very significant method in  medical monitoring . Due to the restriction in the use of the transmission pulse oximeter in high-density tissues, this research aims to focus on the study and development of the reflectance pulse oximeters, because it is able to show the blood oxygen saturation level (2SaO) in various densities. To this end, considering the benefits of photon diffusion theory over Beer-Lambert law, a new mathematical (analytical) method was developed to investigate the inensity reflective light propagation in a heterogeneous medium such as a fingerprint. Then, using the obtained analytical model, source-detector space was optimized so that by decreasing the sensitivity of the motion effects on light scattering the accuracy rate will increase. To verify the results obtained from the analytical model, Monte Carlo simulation results were used as a standard method compared to experimental data. This comparison showed the agreement of the analytical model with the results of these two methods with minor differences. By using the sensitivity function, the optimum distance of the detector from the light sourcewas obtained 4.8 mm and 2.8 mm for red and infrared lights, respectively. An overview of the results suggests that light propagation characteristics can be accurately assessed through an analytical model.

Promethium is one of the rare earth elements of Lanthanides. This element is no found on the earth’s crust. All  its isotopes are radioactive. The isotope 147</sup>Pm is a pure beta emitter and very useful in industry because of its radioactive specifications. To name its applications one can point to usage as beta source in nuclear gauges, self-luminary lamps and nuclear batteries. This radioisotope produces via two methods, one from extraction of fission products waste and the second from thermal neutron irradiation of 146</sup>Nd. In this research, natural neodymium was irradiated in Tehran Research Reactor (TRR) and the gamma and beta spectrums were obtained. In addition, theoretical calculations were done. In this way, acceptable consistency in the results was obtained and the activity and radioactivity of the products were compared.

Urania nanostructures were synthesized by a facile, which is a simple and clean and straightforward deposition method, for two different deposition time durations. The morphology and structures of the products were characterized by the X-ray diffraction analysis (XRD) and Scanning Electronic Microscopy (SEM). The SEM images indicated that the morphology of the synthesized samples for 10 minutes was composed of a coin-like structure with a nano-scale dimension in a narrow- size distribution. The results indicated that the deposition time affects the morphology while it does not affect the structure. The XRD results identified the sample structures as UO2 </sub>crystal. The chemical composition of different points of the sample surface was determined by the energy dispersive spectroscopy (EDS) technique and the results clarified that the samples have a homogeneous composition of uranium oxide. The synergistic properties of the substrate surface, and uranium ions are responsible for the formation of an outstanding and a novel structure.

Soil organic carbon (SOC) plays an important role in the global carbon cycle, and study of dynamics concerns the recent development of nuclear industry. Physical fractionation, radiocarbon dating and FTIR spectrometry methods are among the most important methods for determining carbon dynamics and thereby the magnitude of soil carbon response to land uses. In this study, methodologies of carbon dating and FTIR spectrometry were used to characterize impacts of land use on mean residence times and quality (functional groups) of soil organic carbon based on physical fractionation methods in three land uses including deciduous, coniferous forests and rangelands. The FTIR spectra showed that higher aromatic carbon proportion and its lower decay rate of organic matter in coniferous forest have caused more SOC content. Free and intra-aggregates particulate organic matters (POM) have been recognized as criterion indices for deciduous forest use. Compared to the other land uses, the higher aliphatic to aromatic carbon ratios were obtained in litter and intra-aggregates POM of deciduous forest. The highest14C age in both forest land uses (deciduous and coniferous) was measured in the Bhorizon, while in the rangeland occurred at the A horizon. Aromatic functional groups as well as 14C age are suitable parameters for homification processes.