Destruction Products Research Articles

CLAYEY ROCKS OF THE UPPER PROTEROZOIC SUIROVO FORMATION, WESTERN SLOPE OF THE SOUTHERN URALS: SOME FEATURES OF GEOCHEMISTRY

The article presents the results of the analysis of some geochemical features of the clayey rocks of the Suirovo Formation (Bashkirian meganticlinorium, Southern Urals). It is shown that the Zr/Sc and Th/Sc ratios in mudstones, as well as a number of lithochemical modules, gives reason to believe that thin-grained aluminosilicoclastics of the first sedimentation cycle prevails in their composition. The distribution of the mudstone data points on the La/Sc — Th/Co and Cr/Th — Th/Sc diagrams indicates the presence of a noticeable part of the products of destruction of the basic igneous rocks. The same can be assumed on the basis of their inherent average values (La/Yb)N and Eu/Eu*. Localization of the mudstone data points on the (La/Yb)N — Eu/Eu* diagram with fields characterizing the composition of the fine-grained suspension of the estuarine parts of modern rivers of different categories suggests that the provenances of the Suirovo basin were composed of a diverse complex of rocks (sedimentary rocks, acidic and basic igneous and volcanic rocks), and the rivers that transported thin-grained aluminosilicoclastics were classified as large. On the Th — La — Sc diagram, the mudstone data points tend to the field of compositions typical of oceanic island arcs, which is consistent with their position on the (Fe2O3* + MgO) — Al2O3/SiO2 diagram.

The Use of Products of Microwave Aminolytic Destruction of Polyethylene Terephthalate in Vibration-absorbing Polymer Composite Materials

The aim of this work is to study the possibility of using the products of aminolytic destruction of polyethylene terephthalate (PET) and their derivatives in polymer composite materials with vibration-absorbing properties, which provide effective damping of vibrations of technogenic and natural origin in a wide temperature and frequency range. The paper considers a modern method of recycling PET waste with a mixture of amino alcohols - monoethanolamine and triethanolamine, taken in two different ratios. As a result of the destruction reaction, terephthalic acid diamide (N, N -bis (2-hydroxyethyl) terephthalamide) is formed. To accelerate the destruction process, microwave radiation of various powers of 200, 540 and 700 watts was used. The optimal conditions for aminolytic decomposition of PET were determined: the time and power of microwave radiation with PET conversion up to 95% and the yield of the target product (terephthalic acid diamide) 80-85%. The destruction process was carried out according to a closed cycle of using reagents, without the use of catalysts and at atmospheric pressure, which to a certain extent reduces the energy consumption and increases the environmental friendliness of this method of PET decomposition. The aminolytic degradation product of PET (terephthalic acid diamide) was used as a monomer in the polycondensation reaction to obtain a new oligomer (terephthalic acid oligoesteramide). The degree of polymerisation (n) is in this case 7 to 11 (number of chain links). The obtained oligomer and the PET degradation product were investigated as new components in elastomeric compositions based on chloroprene rubber and in compositions based on thermoplastic elastomers. It has been demonstrated that the introduction of an oligomer based on a PET degradation product reduces the viscosity of elastomeric compositions by 25-35%. The study was supported by a grant from the Russian Science Foundation No. 21-79-00301, https://rscf.ru/project/21-79-00301/.

On the question of determining the quantity of energy necessary for the disintegra-tion of rocks to a certain size

An analysis of the existing classical theories of determining the amount of energy re-quired for the disintegration of solid bodies is carried out. The classical energy hypothe-ses of the destruction of Rittinger, Kick-Kirpychev and Bond can be combined by the formula of the so-called generalizing hypothesis , where E1 is the specific energy transmitted per unit volume of the body , which is collapsing. It is necessary to increase the energy of the newly created surface; k - proportionality factor; x - average grain diameter; f(x) is an exponent that depends on the size of the particles. The geo-metric interpretation of the generalizing hypothesis and theoretical and empirical equa-tions of Rittinger, Kick, Kirpychov, Bond, Svensson, Holmes and other authors is shown and it is argued that they complement each other for different degrees of fragmentation. The thermodynamic theory of L. Jingezian and the theory of A. Andreazen are also ana-lyzed. It was concluded that the presented crushing hypotheses are valid for simplified models of destruction based on the geometric similarity of the particles that are de-stroyed and the products of destruction and their physical identity, in the absence of de-fects in the structure of bodies, therefore the need to create a generalized and reliable mathematical model that reveals the main regularities of these processes taking into account the share of internal and especially external friction. The authors, under the guidance of Professor Vasiliev L.M. a new theory of local destruction of rock with symmetric and asymmetric distribution of contact tangential stresses has been developed, which theoretically provides a reduction in the specific en-ergy of destruction by 40-45 times, which makes it possible to search for new ways of controlling the disintegration process with the lowest energy consumption.

An experimental study on flammability characteristics of materials on the premises of buildings of cultural and historical heritage

Introduction. Many cultural heritage sites have been converted into multifunctional buildings, which preserve original architectural and structural solutions but fail to comply with effective fire safety standards in many instants. In the event of fire, safe evacuation must be organized from the facilities, that may accommodate a large number of people at a time. Experimental studies are needed to identify the flammability characteristics of materials that can affect safe evacuation from cultural heritage premises.Goals and objectives. The co-authors suggest a study on the thermal destruction of historical materials, that have been aging in natural operating conditions. The analysis of gaseous products, emitted in the process of thermal destruction, is performed to identify the influence of ancient materials on formation of hazardous fire factors.Research methods. Experimental studies were carried out to determine the fire hazard indicators for various types of wood, used in the operation of the building, to obtain the reliable initial data, necessary to simulate the dynamics of hazardous fire factors (OFP) when calculating the time to the blocking of escape routes from the Winter Palace.Flammability properties of wood samples was identified with the support of the testing laboratory of the PB Research Centre at IKBS NRU MGSU. The studies, conducted using thermal analysis methods combined with IR spectroscopy, were carried out with the support from the laboratory of the Federal State Budgetary Institution “SEU FPS IPL” in St. Petersburg.Results and discussion. The analysis of the results of experiments on materials, has proven that during the thermal destruction of the test samples, regardless of the age and type of wood, acetic acid is released within a certain temperature interval for each sample along with the release of carbon dioxide, and it affects the parameters of fire hazard characteristics of materials.Conclusions. For the first time in Russia, products of thermal destruction of historical materials have been investigated. The data presented in the article illustrate the need for a further study on gaseous products emitted by historical materials during thermal decomposition. The data obtained by the co-authors can be used to determine the calculated values of the fire risk.

Technological Capabilities of Impulse Rotators

In the article “Technological capabilities of impulse rotators” the results of use of impulse rotators in some technological processes, differential adjustment of their motion with kinematic and dynamic vibration exciter are considered. Equation of kinetic energy of impulse rotator allows to determine mutual influence of design elements on rational use of supplied pulse energy for useful work. Positive qualities of kinematic torsional vibration exciters are noted, the main of which is organization of force pulse regularity and its considerable force possibilities of pulse creation. A generalized graph of the change of productivity and wear of the working element of the pulse converter compared to the static one is given.Features of impulse rotators with kinematic excitation of torsional oscillations make it possible to change the mode of work performance, to apply low-energy processes of individual operations. Transportation way of destruction products by the screw with use of an impulse rotator on breeds above average fortress excludes use of the compressor. Machines with rolling and spring impact tools do not correspond to the screw method of destruction products discharge and require compressor use. In this case, the energy intensity of production unit increases more than twice.

Water-Soluble Products of Photooxidative Destruction of the Bisretinoid A2E Cause Proteins Modification in the Dark.

Aging of the retina is accompanied by a sharp increase in the content of lipofuscin granules and bisretinoid A2E in the cells of the retinal pigment epithelium (RPE) of the human eye. It is known that A2E can have a toxic effect on RPE cells. However, the specific mechanisms of the toxic effect of A2E are poorly understood. We investigated the effect of the products of photooxidative destruction of A2E on the modification of bovine serum albumin (BSA) and hemoglobin from bovine erythrocytes. A2E was irradiated with a blue light-emitting diode (LED) source (450 nm) or full visible light (400–700 nm) of a halogen lamp, and the resulting water-soluble products of photooxidative destruction were investigated for the content of carbonyl compounds by mass spectrometry and reaction with thiobarbituric acid. It has been shown that water-soluble products formed during A2E photooxidation and containing carbonyl compounds cause modification of serum albumin and hemoglobin, measured by an increase in fluorescence intensity at 440–455 nm. The antiglycation agent aminoguanidine inhibited the process of modification of proteins. It is assumed that water-soluble carbonyl products formed as a result of A2E photodestruction led to the formation of modified proteins, activation of the inflammation process, and, as a consequence, to the progression of various senile eye pathologies.

Termooxidaition destruction of butadiene-nitrile rubbers and industrial waste

The process of thermooxidation destruction of industrial butadiene-nitrile copolymers of the grades SKN-18, SKN-26 and substandard products is investigated. The process is carried out in aromatic solvents (toluene in the xylene) under the influence of air oxygen in the presence of an adduct of the radical initiator azodiisobutyronitrile with N-metilpirrolidone. The mass-average molecular weights of the resulting products were determined by gel permeation chromatography, and molecular weight distribution calculations were performed. The influence of the temperature and the content of the initiator on the change in the intrinsic viscosity of solutions of the resulting degradation products, depending on the time of the process, is considered. Based on a comparative analysis of the destruction parameters using toluene and xylene at 80 °C and an initiator concentration of 0.8% by weight. It was found that the type of solvent and the time of destruction practically do not affect the process of thermooxidative destruction with the production of low molecular weight polymers with a molecular weight of 40 ? 103. It is shown that in the course of the destruction of industrial rubbers differing in the content of acrylonitrile, the process proceeds with the formation of higher molecular weight compounds in rubbers with a higher content of acrylonitrile units. When carrying out the destruction of substandard rubber SKN-26SNT with high Defoe hardness, it is necessary to increase the concentration of the initiator to 1.1% of the mass. and temperature. The mechanism of thermooxidative destruction of the studied polymers is considered. According to the data of IR spectroscopy and chemical analysis, it was found that the products of thermooxidative destruction of nitrile butadiene rubbers contain oxygen-containing functional groups. Thus, a simple commercially method for producing low-molecular-weight butadiene-nitrile polymers based on special-purpose rubbers and substandard product with functional hydroxyl, carboxyl and epoxy groups has been developed.

The content of extractive substances in the products of destruction of bark-woods wastes generated during long-term storage, taking into account the vertical gradient

The content of extractive substances in the products of destruction of bark-woods wastes generated during long-term storage, taking into account the vertical gradient

Volatile products formed during electrical breakdown of polyethylene terephthalate and polypropylene films in high vacuum

In this article we present the results of time-of-flight mass spectrometry of volatile products formed during the electrical breakdown of polyethylene terephthalate and polypropylene polymer films in high vacuum. During the breakdown of films, all the substance emitted from the breakdown channel is a gas of low-molecular products of destruction of macromolecules. The breakdown mass spectra do not contain lines of carbon molecules, the presence of which could indicate carbonation of the channel. To explain the formation of charge carriers, the ionization mechanism of destruction of macromolecules in an electric field is used without the involvement of impact ionization. The final stage of electrical breakdown (the flow of a high-density conduction current) occurs when the critical concentration of traps and electrons ~1024 m-3 is reached. Keywords: electrical breakdown, mass spectrometry, thermodestruction, ionization, macromolecule, trap.

Летучие продукты, образующиеся при электрическом пробое пленок полиэтилентерефталата и полипропилена в высоком вакууме

In this article we present the results of time-of-flight mass spectrometry of volatile products formed during the electrical breakdown of polyethylene terephthalate and polypropylene polymer films in high vacuum. During the breakdown of films, all the substance emitted from the breakdown channel is a gas of low-molecular products of destruction of macromolecules. The breakdown mass spectra do not contain lines of carbon molecules, the presence of which could indicate carbonation of the channel. To explain the formation of charge carriers, the ionization mechanism of destruction of macromolecules in an electric field is used without the involvement of impact ionization. The final stage of electrical breakdown (the flow of a high-density conduction current) occurs when the critical concentration of traps and electrons ≈ 10^24 1/m^3 is reached.

Clay minerals of the bottom sediments of the Azov — Black Sea basin

The Azov-Black Sea basin is the eastern part of the Paratethys Ocean, surrounded by unevenaged mountain structures of the Crimea and the Caucasus, adjacent to the continental slope of the Archean Ukrainian crystalline massif, as well as the Anatolian mountain system. By their lithological and petrographic composition, geological structures influence the composition of the rocks covering the abyssal sections of the seabed and its modern surface. Deepwater drilling has passed the section of the bottom of the Black Sea and reached the layer of sediments of the Upper Neogene (Upper Sarmatian). The upper layers of the bottom of the Black and Azov Seas are mainly represented by sediments of the Quaternary period belonging to different age intervals, which is associated with repeated changes in the level of the Black Sea basin during continental glaciations. This led to a corresponding change in the level of the basin and, as a consequence, to the influx of terrigenous material (fluvial alluvium and products of destruction of bedrock) into the deep water area. In terms of their lithological and mineralogical composition, bottom sediments reflect the material composition of their sources. At present, the upper layer of seabed sediments up to 7-10 m thick is the most studied. This layer consists of three divisions from 22 thousand years to the present. In lithological terms, this is a layer of pellets enriched in hydrotroilite, a layer of sapropels and modern terrigenous silts. Their origin is closely related to sea level fluctuations and climate change. The study of the lithological composition of bottom sediments can be considered satisfactory, while the knowledge of the finest fraction is insufficient. Preliminary studies of the clay fraction, followed by the participation of the authors in this process, studied the composition and spatial distribution of clay minerals. Among them, hydromicas, montmorillonite, kaolinite, chlorite, and mixed layered formations are the most widespread.

ДОСЛІДЖЕННЯ ЕНЕРГОЄМНІСТІ РУЙНУВАННЯ ВУГЛЕПОРОДНОГО МАСИВУ

Purpose. Study of the physical and mechanical characteristics and energy intensity of the destruction of coal massif rocks by dynamic loads, taking into account the directional change in their properties. The methods. To study and evaluate the energy intensity of the destruction of anisotropic rocks under dynamic loads, experimental studies were carried out in laboratory conditions. The selected samples were saturated with surfactants (surfactants). After the destruction of the samples by dynamic loads, the character of the destruction of the rock was evaluated by the granulometric characteristics using the method of optical microscopy. The energy intensity of the destruction was determined by the amount of work spent on the formation of a new surface of particles of rock destruction products. Findings. The analysis of the granulometric and energy characteristics of samples of coal-bearing stratum rocks showed that with increasing alkalinity of surfactant solutions, a decrease in the specific energy of destruction by explosive loads of quartz rocks is observed. The effect of surfactants on the nature of limestone destruction is especially noticeable. Under the action of explosive loads, the specific energy of destruction when this rock is saturated with soda ash decreases. The saturation of coal with different degrees of coalification practically does not affect the energy intensity of their destruction under impact and explosive loads. The originality. A method of estimating the energy intensity of the destruction of anisotropic rocks under dynamic loads has been developed, taking into account the directed change in their properties under the action of surfactants. The priority of the method is protected by a patent of Ukraine. Practical implementation. The use of surfactants makes it possible to reduce the specific energy of destruction when the rock is subjected to dynamic loads, which creates the basis for the development of new energy-saving methods of crushing the coal massif. Keywords: coal massif, explosive destruction, surfactants, granulometry, dispersion.

Stistaites of the South Urals

Research subject. Rare minerals of tin and antimony – stistaites from natural lead plates from the Severo-Svetlinskaya placer in the Chelyabinsk region and from microspherules of intermetallic compounds in the products of erosion of granites of the Kisegach complex in the Ilmeny Mountains.Materials and methods. Electron probe analysis and laser ablation with inductively coupled plasma were used to study the composition of the predominant minerals of intermetallic compounds in lead plates extracted during the washing of a gold-bearing placer, as well as from metal microspherules in the sandy fraction of eroded granites.Results. Two types of stistaite were identified: lead and arsenic-lead. Lead stistaites is sharply predominant, with its average composition (wt %) being Sb – 47.39, Sn – 38.75, Pb – 13.24, Cu – 0.06. The average composition of arsenic-lead stystaite (wt %) was found to be Sb – 43.89, Sn – 41.06, Pb – 11.02, As – 3.05, Cu – 0.47. Tin-lead microspherules from the destruction products of biotite granites of the Kisegach massif (Ilmeny Mountains) occasionally contain crystals and spotted precipitates of lead stistaite with the composition (wt %) of Sn 53.54, Sb 38.45, and Pb 7.42.Conclusions. It is assumed that, in both cases, the formation of alloys of intermetallic compounds of tin, lead and antimony with inclusions of native copper and iron was associated with granite magmatism.

ACCOMPLISHMENT OF COMPLEX OF ABLUTION OF BLAST FURNACES AT PC INJECTION AND USAGE OF CHARGE MATERIALS OF VARIABLE QUALITY

Operation of blast furnaces (BF) at injection of pulverized coal (PC) and usage of charge materials of nonstable quality results in increasing of slag melt heterogeneity, disturbance of gas-dynamic and heat mode of melt, accompanied by increase of total and lower gas pressure drop along the BF height, nonuniformity of adjacent melt products tappings by mass, chemical composition and temperature, increased burning of air tuyeres. As experience shows, this results in a necessity to arrange special and complex ablutions of the BF hearth to remove coke destruction products and unburnt particles of PC. Property features of ablution materials and regulation of their application considered. Results of ablution of the hearth, coke packing and BF profile of the steel-works in Kamenskoye, Dnepropetrovsk region (now – PJSC DKKhZ MP, before August of 2021 – PJSC “Dnepr steel-works”) presented. Based on comparative analysis of the results of ablution with application of various materials including high-protoxidic sinter and iron-containing briquettes, it was established that mixture of sinter and pellets with iron-containing briquettes were most effective kinds of ablution compositions. A positive experience of manganese-containing materials in BF charge application on continuing basis was considered. The availability of a method of cold roll briquetting for ablution materials agglomeration was shown. The results presented testify to efficiency of the ablution materials application at BF under conditions of their operation with variable charge, fuel and technological parameters. Observation of regulation of ablution accomplishment enables to provide stable operation of BF and reaching required technical and economic indices

Assessment of Phenol Detoxification by Rhodococcus aetherivorans UСM Ac-602 Using the Phytotesting Method

Monoaromatic compounds are related to widespread pollutants of soil and groundwater. Among them phenol is one of the most toxic and carcinogenic compounds. Therefore biodestruction of phenol is of much importance for environment protection. The use of metabolic potential of microorganisms for depolluting environment is a safe and economical alternative to widely used physicochemical methods. Aim. To assess efficacy of phenol detoxification with strain Rhodococcus aetherivorans UСM Ac-602 using the phytotesting method. Methods. Bacteria were cultivated in liquid mineral medium with initial concentration of phenol 500, 750 and 1000 mg/L as a single source of carbon and energy. Cultivation time was 24 h, 48 h and 72 h respectively. Phytotoxicity was determined in express-test with use of seeds of spring wheat variety “Pecheryanka” (Triticum aestivum L.). Plant seeds were incubated by temperature 20±2°C during 7 days in Petri dishes with filter paper treated with respective phenol aqueous solutions or post-fermentative cultural fluids (PFCFs). PFCFs were obtained after cultivation of strain in growth medium with same concentration of phenol. Morphometric parameters of wheat were assessed against control plants cultivated on distilled water. Comparative analysis of samples toxicity and toxicity class determination was performed according to Kabirov method by calculation of index of test factor toxicity (ITF). Results. Phenol aqueous solutions and PFCFs were much different in effect on wheat. Phenol solutions 500 and 700 mg/L have shown significant inhibitory effect on all initial growth parameters of test plants. The weakest growth inhibition was induced by phenol concentration of 500 mg/L which caused decrease in number of germinated seeds by 59.6%, shoot length – by 59.7%, root length – by 84.5%, sprout dry weight – by 35.0%. In the presence of phenol concentration of 750 mg/L these indicators increased by 7−30%; roots of test plants were the most sensitive to effect of phenol. Phenol concentration of 1000 mg/L caused total seed mortality. Unlike phenol aqueous solutions PFCFs have shown insignificant effect on all morphometric indicators of plants compared to control. Similar effects on plants were observed in the presence of PFCFs obtained from cultivation of strain R. aetherivorans UСM Ac-602 in the growth medium with initial concentrations of phenol of 500 and 750 mg/L. Under the influence of these PFCFs, the number of germinated seeds decreased on average by 15.8%, root length decreased by 19.8%, at the same time shoot length and their dry weight increased by 17.8% and 7.2% respectively. More negative effect on wheat was shown by PFCF obtained after strain cultivation on medium with phenol concentration 1000 mg/L. It caused reduction in number of germinated seeds by 18.0 %, shoot length – by 25.3%, root length – by 29.0%, sprout dry weight – by 7.2%. For phenol aqueous solutions ITFs had much lower values 0–0.40 than for PFCFs (0.71–1.0). Conclusions. Based on data obtained in this research it was concluded that strain R. aetherivorans UCM Ac-602 performs active detoxification of high-concentrated phenol-containing media. Analysis of calculation results for ITF medium values (ITFm) had shown that under the influence of studied strain there was a decrease in toxicity of phenol solutions (500, 750 and 1000 mg/L). According to Kabirov toxicity scale it was assessed that toxicity of phenol solutions with initial values of classes II (high) and I (very high) was decreased to IV (low) and V (normal level). Our results demonstrate ecological safety of the end products of phenol destruction with strain R. aetherivorans UCM AC-602 and prospects of its use in biotechnologies for environment detoxification from phenol pollutions.

Peculiarities of biogenic elements migration in case of complex utilization of bioorganic component of municipal solid waste

Finding solutions to the problem of municipal solid waste management is impossible without involvement in the waste management system of the largest group of wastes – bioorganic waste, which form up to 60% of the municipal solid waste total mass. The aim of the article is to analyze the redistribution of biogenic elements subject to implementation of the Concept of solid municipal waste management by OSENU and subsequent utilization of bioorganic waste flow. Research methods include mass balance and equations of methane generation. The article presents the results of research on the biogenic elements migration in case of complex utilization of bioorganic component of municipal solid waste. The study shows that processing of easy-decomposed organic waste into a gaseous fermentation product and biomineral fertilizer allows full involvement of biogenic elements in natural cycles. The processed solid products present an additional source of organic matter and biogenic elements needed by soil. In the event of humus and nutrients shortage in soil the retrieved-from-waste fertilizer becomes an important secondary resource, containing up to 65% carbon and almost 100% nitrogen, phosphorus and potassium. The rest of carbon is released with biogas and is eventually involved in natural cycles. Burial of such waste results in localization of biogenic elements in a landfill's body and gradual release of carbon with the products of destruction (27% over 50 years). All this data indicate the need for efficient use of such waste resource potential which is possible in case of easy-decomposed organic waste separation at the beginning of the municipal solid waste life cycle. Combustion releases only carbon in the form of carbon dioxide, the rest remains in ash. However, complex utilization of easy-decomposed organic waste ensures complete return of biogenic elements to the environment. Reuse of secondary raw materials in the form of paper and textile waste minimizes involvement in economic turnover of carbon from natural sources.

Suppression of decarbonization and resource characteristics of carbonated spinel-corundum refractories in steel-ladle lining

Experimental studies of changes in the pore structure and physical and technical properties of carbonated spinel-corundum refractories under different conditions of decarbonization and the formation of a protective regulatory layer on their hot surface, suppressing decarbonization of the refractory material and mass transfer between the lining and the flow of slag melt, are presented. The results of industrial tests of carbonated spinel-corundum refractories in the working layer of the lining of a 400-ton steel-ladle lining, as well as the topography and consumption specific coefficients of refractories for the functional zones of the ladle lining, the amount of refractory destruction products of the lining during its operation are considered.

Impact of High Inertia Particles on the Shock Layer and Heat Transfer in a Heterogeneous Supersonic Flow around a Blunt Body

One of the most important and complex effects associated with the presence of particles in the flow is the gas-dynamic interaction of particles with the shock layer. Of particular interest is the intensification of heat transfer by high inertia particles rebounding from the surface or by the products of erosion destruction, which reach the front of the bow shock wave and violate the gas-dynamic structure of the flow. In this case, according to experimental data, the increase in heat fluxes is much greater than it could be predicted based on the combined action of the kinetic energy of particles and a high-speed flow. The problem is related to the destruction of the flow structure. In this paper, the problem is studied with numerical simulation. We show that the key role in the intensification of heat transfer is played by the formation of an impact jet flowing onto the surface. An area of increased pressure and heat flux is formed in the zone of action of the impact jet. This effect is maintained over time by the successive action of particles.

Use of microwave aminolytic destruction products of polyethylene terephthalate in rubbers based on chloroprene rubber

Use of microwave aminolytic destruction products of polyethylene terephthalate in rubbers based on chloroprene rubber

Characteristics of shell fragments after hitting triplex car glass with shots from a hunting “Saiga” carbine under the 5.45×39 cartridge

Background: The article aims to assess the possibilities of innovative research methods in scanning electron microscopy (SEM) with energy dispersion analysis (EDS) forensic medicine. The described methods were used in experimental studies of a gunshot retrograde injury. Aim: The purpose of this study was to evaluate the particles formed during the destruction of a semi-shell shell and an obstacle (triplex car glass) when fired from a hunting Saiga carbine with 5.4539 cartridges. Material and methods: Triplex windshields from BMW and Mercedes-Benz cars were used as barriers. The shots were fired from a hunting Saiga carbine with a 5.4539 cartridge from a distance of 10 m. As targets, white calico with dimensions of 100150 cm was used, while stretched on a wooden frame or fixed on a chipboard. The distance between the target and the barrier was 100 cm, which approximately corresponded to the distance from the car windshield to the driver and the passenger in the front seat. The studies were conducted using the SEM Hitachi FlexSem1000 II and the energy-dispersive X-ray spectrometer Bruker Quantax 80. Results: Microscopy helped identify seven types of foreign bodies on the surface of the target, which were the products of destruction of the fire projectile and the barrier: glass fragments, glass fragments, crumbly depositions of glass particles, glass fragments caked with the projectile metal, fragments of the projectile, spherical metal particles, and overlays of molten metal in the form of puddles. EDS helped determine the elemental composition of the barrier particles, fire shell, and the overlap of target particles. Conclusion. The experimental study demonstrated that the use of SEM and EDS significantly increased the effectiveness and evidence-based expert research value while solving the problems of causing damage through the barrier-the windscreen of modern cars.