JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY
Year:2003 | Volume:- | Issue:27|Papers Count:10

Pure early soybean mutants evolved through mutagenesis (Co-60) from cultivar Clark irradiated with doses 100Gy, 150Gy, 200Gy and 250Gy (absorbed dose) were evaluated for agronomical traits and compared with two commercial cultivars ; Clark and Williams in two regions, Karaj and Alishtar. Experimental design was conducted in a simple lattice (7m x 7m) with two replications. A significant statistical difference in yield existed at 1 and 5 percent level among mutant lines and between mutants – Williams and mutants– Clark, respectively in Karaj. The mutant line number 47 placed itself at the top of the list with the yield of 4782 Kg /hect. , followed by mutant line number 38 with 4722 Kg/hect. .A number of mutant lines matured between 10 to 12 days earlier than the commercial soybean cultivars used as checks in the experiment. In Alishtar seed yield of mutant lines compared to the cultivar Williams showed a significant difference at 5% level. The highest seed yield of 3147 Kg/hect. belonged to the mutant line 47 which also matured two weeks earlier compared to the cultivar Clark. The compound analysis of seed yield in Karaj and Alishtar showed superiority of 15 mutant lines over the cultivar Clark and 36 mutant lines over the cultivar Williams. The mutant line number 18 producing seed yield of 3643 Kg/hect. ranks first in the list while, it matured earlier than both check cultivars, Clark and Williams.

A sun tracker system, consists of two parts (opto-electronic and hydraulic), has been designed and fabricated to be used in solar thermal power plant. In this paper various parts of the system including optical sensors, electronic circuits, computational control and mechanical lever have been explained and the operational mechanism of each one is discussed. The parabolic mirror used in this plant has 400 cm length, 570 cm width and 170 cm focal length. Rays falling parallel to the axis of mirror are reflected and collected at the focal point, while unparallel rays are diverted. To determine the rate of divergence, a three – dimensional equation of radiation path is written. Using a computational program in "C" language the error is calculated from "0" to "0.5" degree, for modifying the operational error of the optical system. The optical sensors detect the beam deviation from the mirror,s principal axis with a precision of 0.1 degree and transfer the necessary corrections to the active mechanical system of the hydraulic type. A three phase electromotor of 0.7 kW power and one thousand revolutions per minute controls the mirror movement.

An improved method for measurement of 90Sr was based on Tributylphosphate (TBP) extraction of the radio-Yttrium and oxalate precipitation to remove bulk Potassium. The Cerenkov radiation produced by the high energy beta emission of 90Y was measured with 1220 Quantulus liquid scintillation spectrometer. The minimum detectable concentration (MDC) was 0.0053Bq for 180 minute and 95% confidence level 90Sr activity concentration in mineral samples was from 0.0192 to 0.193 Bq.

Trace elements play an important role in the biophysiology of cells by affecting their growth and contributions to various biological processes such as wound healing. Determination of toxic trace elements in biological fluids is an important subject of interest for toxicological purposes. Increasing the concentration of these elements in the blood levels, cause serious diseases in patients. Recently instrumental analysis procedures such as atomic absorption spectrometry have been used in clinical measurements for determination of many toxic trace elements in the biological samples. In this paper we are reporting the study of various methods of blood and serum samples preparation for determining the toxic trace elements of Arsenic and Chromium. The measurement of this elements performed by using electrothermal atomic absorption spectrometry. The best and reliable results for Chromium analysis was achieved by injection of diluted serum samples, where the samples were diluted with HCl 0.1N. In Arsenic analysis, the best results obtained by extraction of blood with aqueous solution of TCA. For determining all of these elements the RSD% was less than 5%.

The Russian nuclear power plant (WWER) with the reactor model V-392 is designed as a Nuclear Power Plant with the enhanced safety WWER-1000 reactor of a new generation. The safety concept has been elaborated in an evolutionary approach based on thorough analysis of operating experience and design solutions of NPP units with V-320. In the reactor model V-392 the fuel, nuclear safety system, neutron and thermal hydraulic design of the reactor core; instrumentation and control, as well as primary and secondary circuit have been modified. This article refers to nuclear safety systems that have been subjected to extensive modifications in comparison with the reactor model V-320 and also play an important part in the nuclear safety level enhancement.

Graphite has several applications in industry. Their physical properties and purity are among the essential factors in industry. Density is a determining factor for the physical properties. There are different methods to increase the graphite’s density. Impregnation of graphite with coal tar pitch is a common industrial process in which it reduces the porosity and increases the density of the graphite. Accordingly, a laboratory scale impregnation system was designed, instructed and enabled us to practically experience the above subject. Variations of the physical properties of the fabricated graphite were also investigated. We achieved with a graphite of a maximum density ~ 1.82 gr/cm3, electrical resistivity coefficient ~ 13.5 W.m, thermal conductivity ~ 93.7 W/m.K, thermal expansion ~ 3.15 10-6 K-1, dynamic young’s modulus ~ 13.56 GPa, compression strength ~ 83.3 Mpa, and bending strength ~ 31.65 MPa, which shows an improving quality for the fabricated graphite.

In this research work, samples of stainless steel 52100 disks were implanted with nitrogen and carbon dioxide ions at the energy of 90 keV. Microhardness measurements were performed to determine the hardness of the surfaces. The N2+ implanted steels at the doses of 1 × 1018 ions cm-2 gave the highest hardness of 49.70%, while for the CO2+ ions implantation, the hardness of 17% and 5% were obtained at the doses of 3 × 1018 and 1 × 1019 ions cm-2, respectively. To support the interpretation of our microhardness results the implanted surfaces were analyzed by the use of XRD method. Our results indicated that the hardness of the N2+ implanted samples are due to formation of beta-CrN phase in the surface layer, while in the CO2+ implanted samples no observation of carbon as graphite or carbide was made. In addition, the absence of any hump in the XRD spectrum indicating that carbon is not in the amorphous phase either.

In this investigation, the response of anther culture in three wheat genotypes (Tajan, Atila, R-12) after a treatment with a low dose of gamma ray was studied. Spikes of these genotypes were irradiated in doses of 2, 3 Gy, then cultured in the modified P4 medium, containing 200 mgl –1 Glutamine, 15% Ficol, 2 mgl –12,4-D, and 0.5 mgl –1 Kinitin. It was found that there is a significant difference between the genotypes, and also between the irradiated treatment levels and the non–irradiated treatment. All of the genotypes showed a low response to the anther culture meaning a decrease in the response with irradiation. 90% of calli of Atila, 67% of R-12 and 46% of tajan in control treatment produced plants. But the calli of irradiated anthers did not produce any plant (green or albino). Generally by the gamma irradiation, we observed a low response in the calli and plantlet production.