[en] The He⁺ ion on a plane subject to a constant magnetic field B perpendicular to the plane is considered taking into account the finite nuclear mass. Factorization of eigenfunctions permits to reduce the four-dimensional problem to three-dimensional one. The ground state energy of the composite system is calculated in a wide range of magnetic fields from B=0.01 up to B=100a.u. and center-of-mass Pseudomomentum K from 0 to 1000 a.u. using a variational approach. The accuracy of calculations for B=0.1a.u. is cross-checked in Lagrange-mesh method and not less than five significant figures are reproduced in energy. Similarly to the case of moving neutral system on the plane a phenomenon of a sharp change of energy behavior as a function of K for a certain critical K_c but a fixed magnetic field occurs

[en] Tensegrity structures are composed by pre-stressed pin-jointed compression (struts) and tension (cables) members that are self-equilibrated. They have had a great development in the last years owing to their ingenious forms, lightweight, deployability and controllability. A challenge related to the design of tensegrity structures is the determination of the force densities during the form-finding process that leads to a stable tensegrity. In this work, the octahedron tensegrity is used as a source of new tensegrity forms. A family of tensegrity structures is a group of them that share a common connectivity pattern. A set of force densities that achieve an equilibrium shape of tensegrities based on the octahedron family was computed analytically. Several examples are shown.

[en] Dosimetry in patients treated with radiopharmaceuticals needs to be carried out for each individual treatment. No standardized procedure is currently available. In our study, the dosimetry for each individual treatment has been calculated using the dose protocol of the Sociedad Espanola de Fisica Medica for the treatment of thyroid cancer with 131I. This protocol is currently under review, since it proposes a procedure which only uses the daily external dose rate measurements during the patient hospital stay and an external dose rate measurement performed 7-9 days after the activity administration. The results obtained seem to be consistent with those found by other authors following different procedures. Moreover, this protocol has proved to be very useful to verify the values of doses established for red marrow are not exceeded. The maximum activity that can be administered in later treatments could also be assessed with this procedure. Additionally, the activity in urine, which cannot be measured directly, was determined. The potential dose which any patient's relative or any person staying close to the patient might receive during the treatment was determined as well. These results make it possible to establish more realistic criteria regarding radiation protection. (Author).

[en] Low-lying bound states for the problem of two Coulomb charges of finite masses on a plane subject to a constant magnetic field B perpendicular to the plane are considered. Major emphasis is given to two systems: two charges with the equal charge-to-mass ratio (quasi-equal charges) and neutral systems with concrete results for the hydrogen atom and two electrons (quantum dot). It is shown that for these two cases, when a neutral system is at rest (the center-of-mass momentum is zero), some outstanding properties occur: in double polar coordinates in CMS (R,ϕ) and relative (ρ,φ) coordinate systems (i) the eigenfunctions are factorizable, all factors except for ρ-dependent are found analytically, they have definite relative angular momentum, (ii) dynamics in ρ-direction is the same for both systems being described by a funnel-type potential; (iii) at some discrete values of dimensionless magnetic fields b≤1 the system becomes quasi-exactly-solvable and a finite number of eigenfunctions in ρ are polynomials. The variational method is employed. Trial functions are based on combining for the phase of a wavefunction (a) the WKB expansion at large distances, (b) the perturbation theory at small distances (c) with a form of the known analytically (quasi-exactly-solvable) eigenfunctions. Such a form of trial function appears as a compact uniform approximation for lowest eigenfunctions. For the lowest states with relative magnetic quantum numbers s=0,1,2 this approximation gives not less than 7 s.d., 8 s.d., 9 s.d., respectively, for the total energy E(B) for magnetic fields 0.049a.u.< B<2000a.u. (hydrogen atom) and 0.025a.u.⋜B⋜1000a.u. (two electrons). The evolution of nodes of excited states with the magnetic field change is indicated. In the framework of convergent perturbation theory the corrections to proposed approximations are evaluated. -- Highlights: •Approximate solution for the low-lying eigenstates for two Coulomb charges given. •Factorization of eigenfunctions in double polar center-of-mass coordinates uncovered. •A magnetic field range varies from weak to ultra-strong, 1000–2000 a.u

[en] One of the main present challenges that all the countries have to engage with is the environmental degradation due to the human action. Industry generates high quantities of materials rendered useless during the manufacturing process. Electric Arc Furnace Dust (EAFD) is a hazardous industrial waste due to its high content in heavy metals. In this paper, the solidification of EAFD within the hydrated Portland cement matrix is proposed as a possible solution for its stabilization. Four concrete mixes were produced varying the content of EAFD as admixture (0, 5, 10 and 15% by weight of cement). The elastic modulus and the density of each concrete mixture were obtained in order to determine their mechanical properties. Results indicate that concrete mixtures that include EAFD as an admixture show a higher elastic modulus and a lower density in comparison with traditional concrete.

[en] The preliminary results of an evaluation of radiological protection carried out in radiology services of different hospitals of Mexico are shown. The evaluated points were: relative aspects of the room, operation parameters of operation of the equipment, work procedures and training about radiological protection for the equipment operators. (authors). 2 refs., 1 fig

[en] Short communication

[en] The future LHC particle accelerator will use a large number of cryogenic sensors and actuators, most of which are located inside the machine tunnel and therefore in a radiation environment. These elements will communicate through a fieldbus. This paper reports the irradiation study carried out on WorldFIP fieldbus communication system. A digital communication system based on WorldFIP fieldbus protocol has been implemented and single event effects and total ionizing dose radiation tests have been performed on it

[en] Since entry into force of the Amendment to the Convention on the Physical Protection of Nuclear Material (CPPNM) [1] and in concordance with UN 1540 resolution [2], each State has the responsibility for the establishment, implementation and maintenance of a physical protection regime of nuclear material. In order to establish control of the nuclear material (even during transport), the State may provide the tools and specific knowledge to the law enforcement agents for detecting, characterizing and controlling the presence of nuclear material out of the regulatory control as soon as possible. The paper is focused on how to improve the information that law enforcement agents obtain on site using their equipment for the detection and characterization of nuclear material. Almost all countries have special teams in the law enforcement corps as first responders against CBRN attacks. These forces always have as a part of their technical equipment a gamma spectrometry portable device for detection and measuring any dose rate and/or the presence of contamination. One typical scenario for the law enforcement agents (i.e., customs control, security control, inspection of any industry or facility) is where they have to detect the presence of nuclear material using this type of gamma spectrometry devices, which raises several issues. First, is it possible to detect nuclear material using gamma spectrometry devices? Although U, Pu and Th are alpha emitters, law enforcement agents also need to know that they have gamma emission as well and due to alpha decay and the presence of emission of gamma daughter isotopes is possible to detect. Second, in case of U nuclear material, is it possible to distinguish between mineral U, processed U, depleted U and or material enriched in ²³⁵U? Based on aforementioned issues, this work presents the first results obtained in CIEMAT by the close collaboration with the Spanish law enforcement corps. The centre of CIEMAT in Madrid is a nuclear facility since 1950’s, ab initio as the headquarters of the JEN (Nuclear Energy Board) where the main activities carried out were related to the development of the nuclear fuel close cycle in Spain. Until 1970’s the uranium extraction process from the minerals of different Spanish mines was done. The process of purification of the mineral consisted of partitioning it from the rest of the components of the matrix by physical and chemical methods, obtaining concentrates of U [3] [4]. In addition, in the former JEN, nuclear fuel manufacturing processes (pyro and hydrometallurgical extraction process) were also carried out, including the enrichment stage for use in nuclear reactors, and the fuel cycle was closed with a reprocessing plant that stopped working at 1973. This background allows to have different small amounts of U nuclear material that can be used for radiochemical measurements using gamma spectrometry portable devices.

[en] The potential health effects of exposure to non-ionizing electromagnetic radiation in public and residential environments are a source of increasing concern for both the public and authorities on environmental health. This work briefly summarizes the theoretical and experimental bases supporting the safety levels proposed by international committees. It also reviews the recent scientific literature on bioeffects on non-ionizing radiation that may prove potentially relevant to the validation or modification of present exposure limits. Because of their social interest, special consideration will be given to power frequency fields (50-60 Hz) and to the radio communication signals of mobile phones. We will also describe how interpretations of scientific evidence from sources other than international committees have generated some controversy and provided basis for more restrictive limits, such as those adopted in Europe by Switzerland and Italy. In addition, this work identifies some gaps in the present scientific knowledge of bioelectromagnetics. Such gaps are largely responsible for the existing controversy and differences in risk perception. This is why more research aimed at broadening and deepening our understanding of biological responses to non-ionizing radiation is urgently needed. (author)