Thermoluminescence of zircon: a kinetic model

The mineral zircon, ZrSiO4, belongs to a class of promising materials for geochronometry by means of thermoluminescence (TL) dating. The development of a reliable and reproducible method for TL dating with zircon requires detailed knowledge of the processes taking place during exposure to ionizing radiation, long-term storage, annealing at moderate temperatures and heating at a constant rate (TL measurements). To understand these processes one needs a kinetic model of TL. This paper is devoted to the construction of such amodel. The goal is to study the qualitative behaviour of the system and to determine the parameters and processes controlling TL phenomena of zircon. The model considers the following processes: (i) Filling of electron and hole traps at the excitation stage as a function of the dose rate and the dose for both (low dose rate) natural and (high dose rate) laboratory irradiation. (ii) Time dependence of TL fading in samples irradiated under laboratory conditions. (iii) Short time annealing at a given temperature. (iv) Heating of the irradiated sample to simulate TL experiments both after laboratory and natural irradiation. The input parameters of the model, such as the types and concentrations of the TL centres and the energy distributions of the hole and electron traps, were obtained by analysing the experimental data on fading of the TL-emission spectra of samples from different geological locations. Electron paramagnetic resonance (EPR) data were used to establish the nature of the TL centres. Glow curves and 3D TL emission spectra are simulated and compared with the experimental data on time-dependent TL fading. The saturation and annealing behaviour of filled trap concentrations has been considered in the framework of the proposed kinetic model and comparedwith the EPR data associated with the rare-earth ions Tb3+ and Dy3+, which play a crucial role as hole traps and recombination centres. Inaddition, the behaviour of some of the SiOmn− centres has been compared with simulation results.

ESTIMATION OF POSTOPERATIVE PAIN SYNDROME AT THE HERNIOPLASTY

The article reviews the problem of course of postoperative period, in patients operated on account of different kinds of inguinal hernias. Age and. gender of patients, kind of hernioplasty, anatomic peculiarities of inguinal hernias were the factors determining intensity and continuance of postoperative pain syndrome. 239 patients had operations during 2007—2011 years. The pain was evaluated by the subjective 10-points scale on the 1st and the 3rd day of postoperative period. Retrospective analysis was used. The aim. of the research was to determine the most significant factors in development of postoperative pain syndrome. Data of retrospective analysis showed that the age of patients is independent prognostic factor that determines pain syndrome in postoperative period at the inguinal hernias, but the gender, anatomic characteristics and surgical technique (not the type of operation) don't influence pain syndrome. Thus the age of patients should be taken into consideration at the prescription of analgetics in postoperative period

Radiolysis of NaCl at high and low temperatures: development of size distribution of bubbles and colloids

New experimental results are presented on low temperature irradiation (18 °C) of rock-salt samples which had been exposed to initial doses up to 320 GRad at 100 °C. Differential scanning calorimetry (DSC) shows that the latent heat of melting (LHM) of sodium colloids decreases during subsequent low-temperature irradiation, whereas the stored energy (SE) increases slowly, indicating that the process of radiolysis continues. The decrease of the LHM is due to dissolution of large colloids, because the intensities of the melting peaks decrease during the second stage irradiation at low temperature. The model is formulated to describe the nucleation kinetics and the evolution of the size distribution of chlorine precipitates and sodium colloids in NaCl under high dose irradiation. It is shown that the mechanism of dissolution of large Na colloids during low temperature irradiation can be related to melting of sodium colloids.

Theory of a quodon gas. With application to precipitation kinetics in solids under irradiation

Rate theory of the radiation-induced precipitation in solids is modified with account of non-equilibrium fluctuations driven by the gas of lattice solitons (a.k.a. quodons) produced by irradiation. According to quantitative estimations, a steady-state density of the quodon gas under sufficiently intense irradiation can be as high as the density of phonon gas. The quodon gas may be a powerful driver of the chemical reaction rates under irradiation, the strength of which exponentially increases with irradiation flux and may be comparable with strength of the phonon gas that exponentially increases with temperature. The modified rate theory is applied to modelling of copper precipitation in FeCu binary alloys under electron irradiation. In contrast to the classical rate theory, which disagrees strongly with experimental data on all precipitation parameters, the modified rate theory describes quite well both the evolution of precipitates and the matrix concentration of copper measured by different methodsComment: V. Dubinko, R. Shapovalov, Theory of a quodon gas. With application to precipitation kinetics in solids under irradiation. (Springer International Publishing, Switzerland, 2014

АКТУАЛЬНОСТЬ ОЦЕНКИ ПРОИЗВОДСТВЕННОГО РИСКА НА АВИАПРЕДПРИЯТИЯХ

The notion of “the concept on assumed risk” that took over from the outdated concept of absolute security is analyzed, the increasing significance of operating risk assessment at the present stage is noted. Some basic risk assessment techniques are considered. Matrix technique of risk assessment is considered more thoroughly, and it may be used in risk assessment of airlines in the context of labour protection management system.The ability to correctly assess risks and develop appropriate precautionary measures will allow airlines to avoid incidents leading to drastic consequences for staff, as well as to direct and indirect costs for the enterprise among which there could be singled out both direct property damage and loss of profit and expenses connected to incident investigation, penalty and compensation payment, loss of business reputation and so on. To reduce the rate of accidents and to develop safe activities skills for airlines staff a risk assessment chart is supposed to be implemented, which will be an efficient accidents prevention involving the staff in the process and making them follow safe working conditions.Process risk assessment is an integral part of assessment of the whole enterprise activity and work efficiency of a department and particular workers evaluation system. Labour protection activity should be based on risk identification and its control. Risk assessment is a keystone of labour protection activity planning.Анализируется понятие «концепции приемлемого риска», пришедшее на смену устаревшей концепции абсолютной безопасности, и отмечается возрастающая значимость оценки производственных рисков на современном этапе. Рассмотрели несколько основных методов оценки рисков. Более подробно рассмотрен матричный метод оценки рисков, который можно применять при оценке рисков на авиапредприятиях в рамках системы управления охраной труда.Способность корректно оценить риски и разработать адекватные меры предосторожности позволит авиапредприятию избежать происшествий, ведущих к тяжелым последствиям для работников, а также к прямым и косвенным издержкам предприятия, среди которых можно выделить как прямой ущерб имуществу и потерю прибыли, так и затраты, связанные с расследованием происшествия, выплатой штрафов и компенсаций, потерей делового имиджа и т. п. С целью снижения травматизма и выработки навыков безопасного поведения у персонала на авиапредприятиях предлагается внедрить карту с оценкой рисков, которая будет является мощным инструментом предупреждения аварийных ситуаций с вовлечением всего персонала в процесс предупреждения аварийных ситуаций и соблюдения безопасных условий труда.Оценка производственных рисков является неотъемлемой частью оценки всей деятельности организации и системы измерения качества работы подразделений и отдельных работников. Работа по охране труда на предприятии должна основываться на выявлении имеющихся рисков и управлении ими. Оценка рисков является при этом краеугольным камнем планирования по охране труда