The directional response of a scintillation detector to γ-rays has been studied for the full energy peak. The directivity
measured has a lower value than that one corresponding to the total spectrum. This behaviour was attributed to the degradation
of the peak-to-total ratio with the angle of γ-ray incidence.
Authors:A. Ballester-Bolinches and R. Esteban-Romero
A characterisation of finite soluble groups in which Sylow permutability is a transitive relation by means of subgroup embedding
properties enjoyed by all the subgroups is proved. The key point is an extension of a subnormality criterion due to Wielandt.
The environmental contamination of transuranics following the Palomares accident in 1966 (Southern Spain) has been continuous monitored on land and scientific programs are still running. The study of the land to sea transfer of the contamination started in 1986, focussed on the depositional history recorded in marine sediments. At the continental shelf, south of the mouth of the Almanzora river, enhanced levels of plutonium and americium were found which could be related to the accident. Additional analysis of marine sediments, collected far from the impact point, showed the presence of a hot particle. The study of the chronology of this sediment core and the isotopic ratios are given in this paper to assess the origin and pathway of the particle. The route of this particle was found to be the aerial transfer at the time of the accident.
Authors:J. Rincón, M. Romero, A. Hidalgo, and Ma. Liso
It has been determined the thermal behaviour at high temperatures of an iron aluminum arsenate mineral first described in
the location of La Serena Valley, Extremadura, Spain, which expands until 1173 K contracting later and softening at 1653 K
and full melting at 1773 K. The DTA/TG experiment only detects some rearrangement with an endothermic at 1173 K due to the
mica mixing. The mineral is a scorodite variety mixed with micaceous clay which has been found as aggregates of pyramidal
crystals associated with quartz, wolframite, molibdenite, cassiterite and other secondary minerals in the pegmatite of the
San Nicolas mine. The chemical composition, the physico- chemical characteristics such as density and hardness, as well as
the thermal behaviour has allowed to conclude that this mineral can be an Al-enriched scorodite (mansfieldite): (Fe, Al) AsO42H2O mixed with illite from the scorodite-mansfieldite series.
Authors:A. Acosta, I. Iglesias, M. Aineto, M. Romero, and J. Rincón
IGCC slag is a vitreous residual product from the new induction gasification combined cycle gasification thermal power plants. In order to characterize this waste as secondary new material for the production of new glasses and glass-ceramics as construction materials; this slag from the Puertollano, Ciudad Real, Spain power plants has been fully thermally investigated. After controlled heating this waste gives rise to hematite, anorthite, and cristobalite crystallized materials.
Authors:C. Gascó, L. Romero, E. Mingarro, and A. Lobo
As a consequence of an accidental release of transuranics at Palomares (Almería, Spain) a land area of 2.3 km2 was contaminated. After the clean up operations, a transuranics residue remained in the ecosystem.1–2 Therefore the Palmoares zone provides a natural laboratory for experimental studies of the transuranic land to sea transfer and factors controlling its distribution in the Mediteranean coast. The geochemical and textural composition of sediment, together with the distribution and inventories of plutonium, americium and cesium were studied in 36 stations between Cape of Gata and Cape of Palos. An enhanced transuranics concentration was observed in sediments from the southern coastal area of the Almanzora river mouth.3–5 The causes of the increase are studied in this paper considering the geochemical behavior of plutonium, americium and cesium in the water column and sediment.
Authors:J. M. Salas-Peregrin, M. A. Romero-Molina, M. A. Ferro-Garcia, and M. N. Moreno-Carretero
The thermal decomposition processes of the complexes of 6-amino-5-nitrosouracil with Fe(II), Co(II), Ni(II) and Cu(II) have been studied using TG and DSC techniques. Dehydration energies have been calculated from the DSC curves.
Authors:M. P. Sánchez -Sánchez, J. M. Salas -Peregrín, M. A. Romero -Molina, and J. Ruiz Sánchez
The following Zn(II), Cd(II), Hg(II) and Hg(I) complexes of 4-amino-1,6-dihydro-2-methylthio-5-nitroso-6-oxopyrimidine (MTH) have been prepared and their thermal behaviour studied by TG and DSC techniques: Zn(MT)2·3H2O, Cd(MT)·H2O. Cd(MTH)Cl2, Hg(MTH)Cl2 and Hg2(MT)(NO3). The dehydration and dehalogenation enthalpy values were calculated.
Authors:J.J. LaBrecque, P.R. Cordoves, P.A. Rosales, F. Audemard, and G. Romero
Immediately, after the July 9, 1997 earthquake (Ms = 6.8) in the state of Sucre, Venezuela, we began measuring radon in water to investigate the possible correlations with the seismic activity and to study the meteorological affects. Sampling periods were for 3–5 days with 4–8 weeks in between each. During the first two sampling periods, the seismic activity was high with several minor events (Mb4.0) and anomalous radon concentrations were measured and considered as possible precursors for the events. We have also shown that the radon activity was stable except for daily meteorological effects during periods of low seismic activity. The radon activity during the first year after the major event on July 9, 1997, at the beginning of the rainy season increased from about 50 pCi/l to about 350 pCi/l for all sampling points. Then abruptly dropped to 100 pci/l at the beginning of the next rainy season for points #1 and #2 in the Casanay river and stayed relativelystable during the second year. At the start of the third year, the values began to increase again, similarly to the first year. We concluded that this was caused by the heavy rainfall at the beginning of the rainy season. While at the sampling points at Hotel Cristal, thermal spring pool, it decreased slowly during the second year but increased again at the onset of the third year. Finally, we have concluded as other investigators, that monitoring radon activity alone is insufficient to predict minor earthquakes (Mb4.0), but in some cases it can be considered as a precursor.