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Treatment of cellulose with ionizing radiation (γ-rays, accelerated electrons) provides the possibility to reduce its molecular weight, change the molecular weight distribution, increase the esterification reactivity and affect other physical and chemical characteristics. The acquired properties, in turn, make it possible to obtain then esters with the desired characteristics. We present the results of studying the effect of γ-irradiation of industrial grades of cellulose on the esterification products, i.e., lacquer colloxylins and xanthogenates. It is found that γ-irradiation at a dose of 3 - 5 kGy prior to mercerization leads to an increase in the reactivity of the polymer in the reaction of xanthogenation by more than 30%. Nitro derivatives corresponding to the technical characteristics (conditional viscosity and nitrogen content) of colloxylins of different grades were obtained by irradiation at a dose of 20 and 30 kGy. It is shown that the stages of prehydrolysis and reduction of nitrocellulose viscosity during its treatment in autoclaves can be excluded when producing colloxylins. It appeared possible to reduce significantly the consumption of carbon disulfide in the technology of xanthocarbon production. The results obtained can be used in developing optimal modes and performance criteria for radiation pretreatment of cellulose of different grades during nitration and xanthogenation proceeding from changes in their physical and chemical properties upon γ-irradiation.

This paper reports the results of investigations on the radioecological state of bottom sediments of the Ob–Yenisei shoal area and Ob and Yenisei estuaries. Materials were obtained in two periods: 1995–2001 and 2014–2019 during seven expeditions on the R/V Akademik Boris Petrov, Professor Shtokman, and Akademik Mstislav Keldysh. Resampling of bottom sediment cores at key-points in areas of increased radiocesium activity and subsequent analysis of the radionuclide distribution made it possible to establish positive trends in the change of the radiation state of the regional ecosystem. The total degradation of the Ob radiocesium overactivity zone and quite significant degradation of the Yenisei zone (primarily the most polluted) were revealed. Comparison of current max-positions of specific activity in the vertical distribution of 137Cs in sediment cores made it possible to determine the sedimentation rate in the distal and proximal facies of the Yenisei estuary: 4.7–5.8 and 3.2–3.7 mm/year, respectively. The established changes that have occurred over ~20 years prove the ability of the Kara Sea ecosystem to self-purify. Pollutant diffusion and assimilation by bottom sediments play a significant role in the self-regeneration of the ecosystem. This is most intense in zone of influence of the river–sea geochemical barrier.

The possibility of using a composite material (hereinafter referred to as composite) based on silica gel modified with particles of Fe(III) compounds for the highly efficient purification of contaminated transformer oils and batches of oils for long-term storage is investigated. The KSKG silica-derived composite modified with particles of Fe(III) compounds with an iron content of about 7 wt % (SiO2-7Fe-Amk-600) is found to be more effective when compared with pure KSKG silica gel for removing both acid activators for sludge formation and oil-degradation products from transformer oils. The preservation of the basic properties of oil after its purification on the SiO2-7Fe-Amk-600 composite and storage for 2 years in contact with this composite indicates the possibility of using the new SiO2-7Fe-Amk-600 composite as a stabilizer for the original and purified transformer oils.

This paper reports the results of investigations in September 2017 on the radioecological state of bottom sediments of the East Siberian Sea during integrated research of the Siberian Arctic seas on cruise 69 of the R/V Akademik Mstislav Keldysh. Evaluation of the results of γ-spectrometric analysis found that the current specific activity of artificial cesium-137 in sediments is two orders of magnitude below the acceptable level and reflects the influence of global fallout from the atmosphere only. Sediments are not contaminated with heavy metals either. Bottom sediments are represented by silts: pelitic, aleuritic–pelitic, and fine aleuritic with a content of pelite (

Experiments on measuring the separation efficiency of evaporation residues produced in complete fusion reactions with heavy ions have been performed on the MASHA mass separator. A new design has been developed for a hot catcher based on the use of thin paper from graphite nanotubes and graphene. The catcher is to be used for the synthesis of nuclei at a high intensity of the primary beam to increase the efficiency of separation. A 16-strip silicon detector was used for continuous monitoring during an experiment to measure the mass spectrometer’s efficiency of separation in the intermediate focal plane.

This article covers the retrospective analysis of the results of treatment of 47 children aged 9 to 17 years with V metacarpal neck fractures, based on the data of radiation studies. The treatment of fifth metacarpal neck fractures, without reduction, does not have a reliable positive result. At large angles of deformity of the V neck of the metacarpal (>45°), the use of closed reduction leads to a significant positive therapeutic effect in the immediate observation period. However, from our point of view, the persistence of the displacement V metacarpal bone with sufficiently large degree in certain cases and the presence of posttraumatic changes in the structure of the heads, subcapital and growth zones in the observed patients cannot satisfy specialists from the standpoint of modern children’s traumatology. Thus, changes in the structure of the heads and subcapital zones in the long-term radiological control of the group were found in 11. 1% of patients who were treated without reduction with a stabilizing plaster cast and in 55% of patients who underwent closed reduction of the metacarpal fractures. The predominance of the narrowing of the growth zone of the injured V metacarpal bone occurs in patients who undergo a closed manual reduction, which may be due to the traumatic effect on the physical zone of the primary force or reduction manipulations. All this indicates the feasibility of further scientific research of this problem with the prospect of developing therapeutic technologies that allow to achieve a complete anatomical reposition of the metacarpal bones in pediatric patients.

Changes in the molecular-weight distributions of low-molecular-weight and alkali cellulose after the processes of γ-irradiation and mercerization of cellulose have been studied. The features of the dissolution of irradiated cellulose in an alkaline solution during mercerization have been revealed. It has found that the alkali cellulose produced from the irradiated polymer has increased homogeneity of the molecular-weight distribution. The γ-irradiation of cellulose before mercerization leads to an increase in the reactivity of the polymer in the xanthogenation reaction by 30–50%. An optimum range of absorbed doses for the radiation pretreatment of cellulose prior to a viscose production process has been determined.

The effect of γ-irradiation of cotton cellulose on the molecular-weight distribution (MWD) of the nitro esters prepared from the irradiated cellulose has been studied. It has been established that the degradation of cellulose during the sulfuric acid–free nitration in fuming nitric acid occurs according to a random law with the most probable MWD, whereas the esters obtained in a sulfuric acid–nitric acid nitration mixture are almost uniform in terms of MWD. The rate constants of degradation by nitration increase with the absorbed dose. An increase in the uniformity of the nitro esters as a result of the washing out of the low-molecular-weight fraction improves their physicomechanical characteristics. An equation is proposed for describing the kinetics of degradation of irradiated cotton cellulose during its nitration in fuming nitric acid.

The MASHA facility [1–3] was developed as a high precision mass-spectrometer for heavy and super heavy elements with masses up to 450 a.m.u. It uses ISOL (Isotope Separation On-Line) method. Its unique properties opens great prospective for the investigation of neutron-rich nuclei produced in multinucleon transfer reactions. Mainly nuclei near the neutron N = 126 and N = 152 shell closures are of great interest. This region of nuclei is not so far thoroughly enough investigated while its research has direct relation to the synthesis of super heavy elements. As is known the island of stability close to super heavy elements (Z = 112–118) exists due to the shell effects in nuclei. More detailed investigation of these shell effects can greatly help in the synthesis of next super heavy elements. Heavy neutron rich radon isotopes were produced in the multinucleon transfer reaction 40Ar + 232Th at Flerov Laboratory of Nuclear Reactions, Dubna. Radon isotopes with given masses were detected using two types of detectors: a multi-strip well-type detector (made in Canberra) and a position-sensitive quantum counting hybrid pixel detector of the Timepix type [1]. The latter detector has an array of 256×256 square pixels each with a pitch size of 55 μm for the full sensitive area 14×14 mm2. Radon isotopes implanted into the detector emit then alpha and beta particles until they reach the stable or long-lived isotopes at the end of their decay chains. The positions of radon isotopes, the tracks, times and energies of the beta particles were measured and analyzed. New software for the particle recognition and data analysis of the results obtained from the experiment was developed and used. It has been proven that MASHA + Timepix setup is a powerful instrument for investigation of neutron-rich isotopes far from stability limits.

A new beam diagnostic system based on the PXI standard was developed, tested, and used in the MASHA setup experiment. The beam energy and beam current measurements were carried out using several methods. The online time-of-flight energy measurements were carried out using three pick-up detectors. We used two electronic systems to measure the time between the pick-ups. The first system was based on fast Agilent digitizers (2-channel, 4-GHz sampling rate), and the second one was based on a constant fraction discriminator (CFD) connected to a time-to-digital converter (TDC, 5-ps resolution). A new graphical interface to monitor the electronic devices and to perform the online calculations of energy was developed using MFC C++. The second system based on microchannel plate (time-of-flight) and silicon detectors for the determination of beam energy and the type of accelerated particles was also used. The beam current measurements were carried out with two different sensors. The first sensor is a rotating Faraday cup placed in front of the target, and the second one is an emission detector installed at the rear of the target. This system is now used in experiments for the synthesis of superheavy elements at the U400M cyclotron of the Flerov Laboratory of Nuclear Reactions (FLNR).

It is demonstrated that during secondary refining at the ladle furnace the carbon content of steel and the residence time of the metal in the ladle exert a significant impact on the residual content of non-metallic inclusions (NMI) in steel. Mathematical calculations showed that the dynamic forces have minor effect on the motion of small sized NMI, making it difficult to penetrate deep into the slag.

Methods of increasing the operating reliability of power transformers, autotransformers and shunting reactors in order to reduce the risk of damage, which accompany internal short circuits and equipment fires and explosions, are considered.

Detection of bovine leukemia virus in dried blood spots by the polymerase chain reaction (PCR) was performed using a new format of membrane system for sample collection. The analysis results of liquid and dried samples of bovine whole blood were entirely consistent with each other and with the data of a veterinary laboratory. It was found that any part of a membrane strip with size of 0.5 × 0.5 cm containing an applied sample can be used for detection of a viral DNA copy. Provirus DNA in dried blood spots was stable for 8 days at 37°C and for 24 hours at 60°C. The new system for the sampling of whole blood in the form of dried spots can be used for sampling in field conditions for subsequent laboratory analysis.

The results of the development and the general information about the data acquisition system which was recently created at the MASHA setup (Flerov laboratory of nuclear reactions at Joint institute for nuclear research) are presented. The main difference from the previous system is that we use a new modern platform, National Instruments PXI with XIA multichannel high-speed digitizers (250 MHz 12 bit 16 channels). At this moment system has 448 spectrometric channels. The software and its features for the data acquisition and analysis are also described. The new DAQ system expands precision measuring capabilities of alpha decays and spontaneous fission at the focal plane position-sensitive silicon strip detector which, in turn, increases the capabilities of the setup in such a field as low-yield registration of elements.

A commercial homogenized ingot from alloy 1421 of the Al – Li – Mg – Sc – Zr system is studied. The elemental composition of the phases is determined. Thermograms are obtained for melting and crystallization of the alloy. The temperature ranges and the succession of formation of phases in nonequilibrium crystallization of alloy 1421 are determined.

The radiational-thermal development of coil short circuits due to the action of partial discharges of the first kind when the windings of transformers, autotransformers and shunting reactors become contaminated with metal-containing colloidal particles, formed in the transformer oil as a result of the interaction of the oil with the constructional materials (the copper of the windings, the iron of the tank, the core etc.) is considered. Acriterion of dangerous contamination of the coil insulation of the windings by metal-containing colloidal particles is proposed, namely, 3% of the mass content of copper and iron in it, which, if exceeded, may serve as a basis for recognizing the state of transformers, autotransformers and shunting reactors at a voltage of 110 kV and above the limit. It is shown that filters for continuously cleaning the oil play a considerable role in prolonging the life of transformer equipment.

Measurements of the acidity, optical turbidity, surface tension, and color of transformer oil from 54 power transformers, autotransformers, and shunt reactors are reported. Changes in surface tension, optical turbidity, and color are found to obey adequate linear correlations, while the acidity has no correlation with any of these properties. Numerical criteria for the maximum permissible state (quality) of the oil with respect to optical turbidity and color are obtained. Recommendations to operating staff are provided for cases in which the criteria for optical turbidity and color are exceeded.

The results of a measurement of the contamination of the oil in 66 transformers by metal-containing colloidal particles, formed as a result of the interaction of the oil with the structural materials (the copper of the windings, the iron of the tank and core etc.), and also the results of measurements of the optical turbidity of the oil in 136 transformers when they were examined at the Power Engineering Research and Development Center Company are presented. Methods of determining the concentration of copper and iron in transformer oil are considered. The limiting values of the optical turbidity factors, the copper and iron content are determined. These can serve as a basis for taking decisions on whether to replace the silica gel of the filters for continuously purifying the oil of power transformers and the shunting reactors in addition to the standardized oil contamination factors, namely, the dielectric loss tangent and the acidity number of the oil.

The main indicators of the limit technical state of transformers and autotransformers, for which their further use is impermissible or inadvisable, are considered. The main elements of a power transformer which determine its limit state are the windings and the cores. Important indicators for estimating the technical state of the windings is the wear of the coil insulation, the degree of mechanical fastening of the windings and, in particular, the absence of dangerous deformations. Wear of the coil insulation is estimated from the degree of polymerization and the short-circuit resistance. The cores of the transformer become damaged fairly rapidly during operation. Normalized values of the above indicators are given as well as experience in using them in the Russian Federation and the Ukraine to estimate the limit state of transformers and autotransformers. The amount of inspection in order to reach conclusions on the technical state of a transformer and temporary measures until they are replaced are indicated.

Main aspects of the physicochemical condition of cellulose insulation of windings of power transformers with a long-term service life are analyzed with the aim of determining criteria on the possibility of prolonging the life of the insulation by washing with surface-active substances.

The effect of ionizing radiation on the molecular weight characteristics and ability to be dissolved of high-molecular, high-viscosity sulfite cellulose has been investigated.

Carotid angiography with the use of thorium dioxide for brain tumour diagnosis has been performed in a woman 35 years ago. In the course of angiography thorium dioxide penetrated into the paravascular space with subsequent development of "thorothrustoma" the clinical symptoms of which progressed for years (compression of neck organs and nerves, gradual disturbance of swallowing). As a result of compression a decubitus ulcer and phlegmona of the pharyngeal wall developed. Late diagnosis of the phlegmona and its inadequate treatment resulted in aspiration pneumonia which was a direct cause of the patients death.