[en] Lead equivalent thicknesses of various kinds of blocks (Hollow core, solid, filled, roof) with different thicknesses were determined. These blocks are widely used for building the diagnostic X-rya departments in Syria. Different applied voltages at X-ray tube (65, 85, 100, 125, 150 KVp) were examined. The results showed that the highest lead equivalent thicknesses for hollow core blocks were at 100 KVp. These equivalent thicknesses were 0.4372, 0.7008 and 0.928 mm for block thicknesses of 10, 15 and 20 cm, respectively. it was also found that, the lead equivalent thicknesses for filled, solid and concrete block were 3.5 to 4 times higher than that of the hollow core block for the same thicknesses and the applied KVp. Values obtained for roof blocks were similar to that of hollow core for the same conditions and geometry. (Author)

[en] Arsenazo (III) used in titrate uranium spectrophotometrically in phosphoric acid after its extraction into organic phase. In this work we used arsenazo(III) to complex uranyl ion in pure phosphoric acid and in the aqueous phase. The spectrum of the complex shows that λ max is at 650 nm. The linearity of the method is corelated with acid molarity, it is (1 -4, 10 - 30, 10 - 40) ppm uranium for (0.2, 1, 2) M of phosphoric acid respectively. Uranium in D₂ EHPA stripped by phosphoric acid and then determined by this method. Also it has been applied to determine uranium in pure perchloric acid. The method is direct, rapid, very cheap and relatively accurate. (author)

[en] Uranium peroxide was precipitated from a high purity uranyl nitrate solution using hydrogen peroxide. The thermal decomposition of the obtained peroxide powders at different temperatures resulted in the formation of UO₄, 2 H₂O, UO₃, H₂O, UO₃ , H₂O, Amorphous (A-UO₃), Gamma-UO₃, U₃O₈-Z(H) and U₃O₈-Z (O). The influence of of ammonia content, occluded nitrate ions and rate of heating; on the formation of the above-mentioned phases, was studied using T G, data and X-ray diffraction analysis. The results indicated that the percentage loss in weight for unwashed calcined samples is generally greater than for washed calcined ones in the temperature range from temperature -300 degree C, while the difference in the percentage weight loss for the same samples decreased greatly between 300 and 800 degree C. 1 ne effect of impurities on both endothermic and exothermic reactions is discussed

[en] Uranium is found in Qatrani area (Southwest of Cairo and North of lake Qarun) in various forms in sedimentary rocks. Two important ore materials have been chosen for studying the recovery of their uranium contents namely; the phosphatic sandstone and the carbonaceous shale. The main emphasis in this thesis is the choice of an acid that would selectively leach uranium from thesis ores while leaving calcium phosphate and carbonate minerals minerals almost completely intact. Citric acid was indeed found advantageous due primarily to its strong ability to form stable complexes with uranium over a wide range of PH values beside the possibility of controlling thr solubility of calcium-bearing compounds by adding calcium citrate. The latter is actually characterized by its ability to exist in an unionized or associated from in citric acid solutions. From the general leaching characteristics of both uranium and P₂O₅ from Qatrani phosphatic sandstone by citric acid, it was found that uranium could be completely leached beside the possibility of realizing a differential leaching percent values vs P₂O₅ which is generally of limited solubility. Such a low solubility of P₂O₅ has even been completely inhibited by providing calcium citrate to the citric acid solutions in amounts sufficient to exist in an optimum ionized non-associated state. Such a provision would render the solution unable to carry any further calcium ions thus the breakdown of the phosphate mineral was hindered while uranium has completely been selectively

[en] A new route has been devised, leading to the production of Pox₃ molecules where X=F, Br and I by an on-line process using phosphoryl chloride, POCL₃ as a starting material passed over heated sodium fluoride, NaF, potassium bromide, KBr and potassium iodide, K1 at 535 Centigrade, 690 Centigrade and 480 Centigrade, respectively. The low resolution gas-phase fourier transform infrared spectra reported for the first time showed strong bands centered at 1411.6, 1322.9, 1300.8 and 1285 cm^-1, assigned to υ₁ (a₁), the O = P stretching fundamental of POF₃, POCL₃, POBR₃ and POI₃, respectively. Attempts were made to prepare POCL₂ and POBr₂, by an on-line process using POCL₃ again but passed over heated sodium and potassium bromide for POCL₂ and POBr₂. (author). 16 refs., 6 figs., 2 tab

[en] The phosphogypsum waste burial site was studied in more details of radiation viewpoint. This waste results from phosphate industry. The study covered ground water, nearby houses, air and emission rates of radon from this waste burial site. Results showed increasing of radiation exposure in the studied site and nearby area for both workers and population. Fortunately, this area was studied before instruction of the waste burial site. So it was easy to compare the new results with the previous ones and see the difference. Indoor radon concentration increased about 70%. Results also showed high emission rates which result in significant dose. The site needs continuous monitoring because the amount of phosphogypsum is increasing. Also groundwater should be monitored continuously to see the effect of the waste in the future if it happened. (author). 5 refs., 7 figs., 5 tabs

[en] Atmospheric fallout of ^7Be was measured over a 2 year period (January 1995-January 1997) at Damascus city (33 N, 727 m above sea level). The annual total deposition of ^7Be was found to be 420 and 634 Bq.m^-2 for 1995 and 1996 respectively reflecting a mediterranean climate where two well recognized periods are dominant (wet and dry). The depositions in the wet periods were 303 Bq m^-2 and 517 Bq m^-2 for 1995 and 1996 respectively while unexpected equal deposition rates in the two dry periods were found to be about 117 Bq m^-2. In addition, monthly deposition rate of ^7B2 showed a maxima in February in 1995 and January for 1996. Moreover, a comparison has been set for our measurements and other data obtained at different locations in the word. (author). 20 refs., 4 figs., 3 tabs

[en] The molecular stracture of some new schiff bases derived from di-2,2'-pyridyl glyoxal and primary aromatic amines have been determined C, H, N analysis, soectrophotometric determination of the molecular weight and interpretation of their infrared spectra. (10 tabs., 12 figs., 75 refs.)

[en] Two fertilizer studies were conducted on mature vineyards established with a water harvesting system on a White House sandy 10 am (fine, mixed, thermic, Ustollic Haplargid) soil at the University of Arizona Oracle Agricultural Center. In one study, two grape (Vitis viinifera L.) cultivars, 'Cabernet Sauvignon' and 'Sauvignon blanc', were treated with different levels of ¹⁵ N and P fertilizer and tested for tissue NO₃-N and total-P content. In the second study, eleven grape varieties were treated with three levels of N. Tissue samples were analysed for total P and NO₃-N content, and the ratio of petiole-P to leaf blade-P was determined. When sufficient quantities of both nutrients were provided, N and P interacted positively resulting in increased grape yields. The petiole-P to leaf blade-P ratio correctly monitored the P status of the vines. (author). 20 refs., 6 tabs

[en] N₂-fixation in some legume crops: Faba bean Vicia faba, common bean pisum sativum, lentil lens esculenta, chick pea cicer artinum and vetch vicia arvillia grown under irrigated conditions without Rhizobium inoculation was estimated using ¹⁵N-labelled fertilizer method. Barley was used as a reference crop. Significant differences occured in N₂-fixation capacity among legume crops at flowering and podding stages. The highest percentage of Nitrogen fixed occured in faba bean (88% of total N), while lower values were observed in the other crops: Lentil 84%, vetch 68%, common pea 67% and chick pea 57%. Moreover, amounts of N₂-fixed were 171, 138, 100, 90 and 13 Kg. N. ha^-1 respectively for faba bean, lentil, vetch, common pea and chick pea. This clearly indicates the importance of biological dinitrogen fixation in local legume crops nodulated with indigenous Rhizobium strains regarding to N-soil enrichment. Further investigations must be focused on the selection of both plant species and Rhizobium strains in order to obtain a good symbiotic system. (author). 2 figs