JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY
Year:2003 | Volume:- | Issue:26|Papers Count:12

The Anarg Polymetallic skarn deposit ( Cu, Zn, Fe, Ag, Au) is located on the15 km west of the Posht -e- Badam village in the northeastern part of the Yazd province in central part of Iran. This area is situated in geological domain of the central Iran within the Anarak - Sarcheshmeh - Kharestan copper belt]. The Anarg"s granitoid intruded within the center of north - south trending zone . The K/Ar radioisotope age of this granitoid body is middle Eocene, respectively. Lithologically of this granitoid body is composed of I- type granite, granodiorite, quartzmonzonite and less of tonalite and quartzdiorite. There is one calcic type skarn around this intrusion. The most important country rock is calcic marble, related to the Posht -e- Badam complex. The exoskarn mainly consists of garnet ( andradite- grossularite), clino - pyroxen (diopside - hedenbergite ), amphibole ( tremolite - actinolite), epidote, chlorite, calcite, quartz, magnetite, chalcopyrite, galena and sphalerite, where its high grade metamorphic facies is attained to the primer pyroxen - hornfels facies. The endoskarn minerals assemblage is composed of grassularite, andradite, epidote, chlorite, calcite, tremolite, actinolite, which its thickness is varied between 1-3 meters. The ore minerals occurred in three different localities (anomalies) namely A,B and C. The major part of economic ores are located within the exoskarn zone. This paragenesis not only is related to the composition of hosting, but also reflects the evolutionary processes of intrusion emplacement. The magmatic derived solutions resulted from fractional - crystalization of igneous melt, as well as their interaction with surrounding rock units participates to from the aforesaid polymetallic skarn - type deposit, by metasomatic processes. Skarnification in the Anarg ore field has been occurred in three stages namely:I) , Prograde, II). Retrograde - Metasomatic and III) Hydrothermal stages. The major ore mineralization has occurred during 2 nd stage. This deposit is a lenticular form body, accompanied by irregular massives and less amount of vein and veinlets. Their ores show massive, inclusion, disseminated and less amount replacement type textures. By considering the mineralogical peculiarities and their correlation with phase diagrams, it is concluded that the temprature of the mineral zone formations are as follows: Pyroxen zone , 450 -600oC Garnet zone , 380 -480oC This skarn was formed by contact- infiltration of magmatic derived fluids. This processe has been intensified by fracturing systems of both magmatic and surrounding bodies. Mineralogical investigation ( X.R.D and ore microscopy) show that the major ore minerals are chalcophyrite, magnetite, galena and sphalerite. The Cu-content is varied between 0.35 to 12% , which indicates a remarkable deposit for mining consideration. It has to be mentioned that this deposit is classified as polymetallic - skarn type deposit, by considering the ( Cu, Zn, Fe, Ag, Au,) metals in ore fomation, which is related to the continental margin - type low angle subducted zone .

A self-filtering unstable resonator (SFUR)with a magnification of M=-3 in a Nd:YAG(2w)dye laser has been studied.The dye solution is Rhodamine 6G in alcohol with the concentration of 5 ×10 -3 Mol/lit. The spatial intensity distribution of the resonator has been compared with that of a plane-parallel (PP) resonator of equal length. The output energy in both configurations are comparable (20 µJ ,and 26µJ ,respectively). A significant difference between these two resonators is the laser beam divergence, where beam divergences of 0.77 mrad for the SFUR and 1.6mrad for the plane-parallel resonator have been measured. The brightness corresponding to these two resonators are 1.5× 1011 and 2.2× 1010 W.cm-2.Sr-1, and the pulse widths are 7 and 17 ns, respectively. These figures show clearly that laser resonator based on the SFUR design can increase the laser brightness by a factor of 10,with a beam divergence of a fraction of mrad, compared with the plane-parallel resonator. In order to describe the dynamic behavior of the SFUR design, a numerical calculation based on the rate equations have been used and a good consistency with the experiment has been obtained.

Induction of mutation for the purpose of producing variations in the genepool has been used in recent years. In this experiment the locally adapted rice CV. Moosa-Tarom was used as a high quality, tall and very lodging susceptible mutation material. The main purpose of this project was to evolve lodging resistant mutants of high yielding.The elite seeds of Mossa-Tarom variety after moisture regulation were exposed to 100, 200 and 300 Gy from 60Co source at the Nuclear Research Center. The irradiated seeds were sown in the field along with a comparable number of unirradiated seeds taken as control. All the first panicles of M1 plants were individually harvested and classified according to the dose rate as M2 material. Among M2 plant populations 203 plants that appeared from the agronomic point of view, along with a number of on unirradiated seeds, were selected and moved to the next generations. During subsequent screening for three generations (M3-M5) and due to lodging resistant, height and efficient factors of yield potential some mutant lines were harvested. From these lines in a preliminary and advanced randomized complete design agronomic traits, 13 promising lines were selected. From the experiment, line 43-3 were confirmed, which is characterized by lodging resistant and high yield. This line showed relative superiority and introduced to Rice Research Institute.

In this work the chemical ethanol-chlorobenzene (ECB) dosimeters were prepared. A cobalt-60 irradiation source was used at the dose range of 0-30 kGy. Titration, spectrophotometry, and oscillometry read-out methods were applied, and the latter method was adopted throughout this experiment. The dose responses were found to agree favourably with the ASTM standards. The homogeneity and the reproducibility of the produced ECB dosimeters were also controlled and found satisfactory.

Power supplies which are commonly used in pulsed lasers with the mechanism of electrical pumping are in fact a kind of pulse generator. These systems are of particular importance due to their wide variety of applications, and their use in pulsed lasers are the most important subject of interest. In this article specifications of a pulsed generator which is designed for metal vapor lasers such as CVL lasers will be introduced. Details of the designed circuit, construction, and measurements of the working parameters will be also presented. The maximum output voltage is 10 kV with the pulse width of ~1µsec. The average current is 340 mA and the pulse repetition rate is 29 kHz.

Appraisal of the natural radon gas effects on lung cancer, and its applications for earthquake prediction and uranium, petroleum and ground water exploration are well known in many advanced countries, However, it has been almost neglected in Iran. So, radon production mechanisms in soils and rocks , radon and lung cancer, and radon hazard mitigation are reviewed. In addition, the noted postive and applied aspects of radon are discussed, hoping to show advantages of investigation in this field of study to be carried out in Iran.

In order to determine a suitable level of nitrogen fertilizer for simultaneous increasing the nitrogen fertilizer use efficiency and the yield production under the trickle fertigation system in comparison with the furrow irrigation, an experimental design was conducted in a randomized complete block (RCB) with five treatments and four replications in plots of 35 square meters area. The treatments of N0 , N1 , N2 and N3 received 0 , 100 , 150 and 200 mgN/lit, respectively under the trickle fertigation , and for the treatment of Ns the amount of fertilizer were equal to N2 but under the furrow irrigation system. Fertilization and irrigation were performed by means of two fertigator pumps ( one for urea and the other for ammonium phosphate and potassium sulfate ) . In order to determine the nitrogen fertilizer use efficiency, six plants in the middle of each plot received 15N labeled urea (isotopic form of 14N) through plastic containers. Irrigation schedule and soil moisture monitoring were performed by means of a neutron gauge . The results showed that in spite of increasing the nitrogen levels in the fertigation system, the nitrogen fertilizer use efficiency decreases. In this respect , the treatment of N1 could absorb % 54 of nitrogen fertilizer which indicated that the highest fertilizer use efficiency under the current design condition and the final nitrogen fertilizer use efficiency for N2 and N3 treatments are %39 and %31, respectively. In addition,the traditional treatment (Ns), with %83 losses of nitrogen had the lowest rate of fertilizer use efficiency.

The most important aspects of heap leaching is it"s potential to produce uranium at lower costs, if it is applied to a suitable ore deposit. Prior to set up a heap at industrial scale, it is necessary to collect data on leaching behavior of the ore by laboratory column leaching tests. This paper discusses the research work performed to determine permeability of the ore,the consumption of chemicals, the composition of leach solution and influence of effective parameters on uranium recovery. A laboratory system was developed for simultaneous column leaching test on 6 column with 6 different samples coming from different points of ore body at the same time.Tests were carried out on 3 samples (2 column of each), 1. Main ore body 2. Representative sample from ores 3. Radiometric concentrate of surface sample Dependence of the recovery with the treatment condition, time (d), L/S (l/t), acid(kg/t) oxidant (kg/t), PH, EMF were studied. As a result the recovery of U was more than 90% for a period of 3 weeks and (98% in 4 weeks) while the consumption of acid was 55kg/t.