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Abstract  

An effective modification of the chemical processes has been obtained to dissolve uranium(IV) and extract it as uranium triperoxocomplex, which facilitates its manipulation and final conversion into uranium nitrate as a high purity concentrate.

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Abstract  

Instrumental neutron activation analysis (INAA) is a well-known analytical method for nondestructive, sensitive and accurate determination of elemental composition of geological samples. In the present work twenty-two elements were determined by INAA in nine rhyolitic geological samples from a wolframium ore body Lela, located in the territory of Isla de la Juventud, Cuba. The obtained results are important for the preliminary geochemical evaluation of the studied rocks.

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Abstract  

Instrumental neutron activation analysis (INAA) and gamma spectrometric analysis (GSA) were used for the determination of twenty-one elements in pegmatites of Loma Venturilla area, in Central Cuba. The application of both methods allowed the determination of K, Co, Cr, Sc, Rb, Cs, Ba, Ta, Hf, Th, U, La, Ce, Nd, Sm, Eu, Tb, Ho, Tm, Yb and Lu. The results were obtained with good precision and accuracy. The knowledge of such concentrations is particularly useful for geochemical investigations. The obtained concentration values can be used in studies on the petrogenesis of those rocks. The results facilitate the evaluation and estimation of the main process involved in the generation and differentiation of the melts from which the pegmatites were formed.

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Abstract  

The state of trace concentrations of95Zr–95Nb and134Cs was studied at an initial pH>13 in an uranyl triperoxidate medium using the electromigration method. OH ions governing the potential are adsorbed on the colloidal Nb(V)-hydroxide which leads to an increase in its negative electric charge; while95Zr did not move during the procedure. However, the electrophoretic mobility of the134Cs could be explained in terms of their agglomerations attributed to the interaction of Cs+ ions with water molecules to give larger aggregations.

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Abstract  

It has been established that the coexistence of chemical species structurally different from cerium, is a direct consequence of the time taken for its preparation. Its practical applications, within the scope of purifying uranium, may constitute the most important technological aspect in the process of ionic exchange, to separate141Ce from uranium.

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Abstract  

A number of ammonium uranates have been obtained, all of them different in their X-ray diffraction patterns. This contribution attempts to demonstrate that different series of compounds can be produced depending on the preparation method. The ammonium uranates were precipitated from solutions of uranyl nitrate using gaseous ammonium to determine the effect of precipitation pH on their composition and morphology.

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Acta Agronomica Hungarica
Authors:
R. Maiti
,
S. Kousik
,
H. González Rodríguez
,
D. Rajkumar
, and
P. Vidyasagar

Using a simple and novel semi-hydroponic technique, three experiments were carried out to evaluate salinity tolerance in twelve pipe-line/commercial maize hybrids at the seedling stage. For experiment 1, hybrids were evaluated at 0.10, 0.15 and 0.20 M NaCl. For experiments 2 and 3, hybrids were subjected to 0.25 and 0.30 M NaCl, respectively. The technique simulates a semi-hydroponic system where the upper layers of coco peat medium receive water/or saline solution only by capillary movement, while the roots are immersed in saturated lower coco peat medium. The emergence percentage ranged from 73 to 100% under control conditions, from 50 to 100% at 0.10 M NaCl, from 46 to 100% at 0.15 M NaCl and from 43 to 96% at 0.20 M NaCl. In addition, increasing salinity decreased the shoot and the root length and the seedling dry weight. Several hybrids (VMH 4029, VMH 4028, VMH 4088, VMH 4060, VMH 4033, VMH 4046, VMH 4101) exhibited a high emergence percentage of 80–96% even at 0.3 M NaCl, revealing that these hybrids have high salinity tolerance and also the capacity to produce high yields. This confirms that salinity tolerance and high yield may be combined if pipe-line hybrids which have been confirmed for high yield over multilocation trials are selected and then tested under field conditions in saline-prone areas.

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Abstract  

The electrophoretic mobility of some radionuclides has been measured to understand its attractive or repulsive tendencies towards other charged species in the medium. In this study, the chemical state of trace concentrations of88Y,103Ru,134Cs, and141Ce in the presence of UO 2 2+ , as a dominant component, in strongly alkaline aqueous solutions (pH>13) was characterized.88Y and141Ce settled almost completely as colloidal species; whereas103Ru,134Cs, and uranium remained as ions. These results closely correlate a procedure for defining both the composition of the water in contact with the fuel and the practical applicability of modified sorbents.

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Abstract  

A study was undertaken to determine experimentally the uptake of pollutants into of the different parts of the water hyacinth (Eichhornia crassipes) found in “José Antonio Alzate” dam in the State of México, México. There is evidence for efficient and significant root accumulation of Ti, Mn, Fe, and Ba; but in the upper parts concentrations was consistently determined by the degree of watering. However, a significant input could by derived from a common generic source, such as the atmospheric deposition. The experimental study would, therefore, indicate that water hyacinth species can be highly effective in providing a control and treatment buffer for toxic discharges to the dam.

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Abstract  

An effective method to minimize the presence of141Ce in the final hexahydrated uranyl nitrate recovery product has been obtained. This condition is considered as one prepurification stage in the recovery process of residual nonfissioned uranium in the production of99Mo of fission.

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