bluuebunny/crossref_metadata_2025 huggingface dataset:
Mining high average utility itemsets using artificial fish swarm algorithm with computed multiple minimum average utility thresholds
Authors: Nandhini S.S. , Kannimuthu S.
Published: November 2023

It is obvious that the problem of Frequent Itemset Mining (FIM) is very popular in data mining, which generates frequent itemsets from a transaction database. An extension of the frequent itemset mining is High Utility Itemset Mining (HUIM) which identifies itemsets with high utility from the transaction database. This gains popularity in data mining, because it identifies itemsets which have more value but the same was not identified as frequent by Frequent Itemset Mining. HUIM is generally referred to as Utility Mining. The utility of the items is measured based on parameters like cost, profit, quantity or any other measures preferred by the users. Compared to high utility itemsets (HUIs) mining, high average utility itemsets (HAUIs) mining is more precise by considering the number of items in the itemsets. In state-of-the-art algorithms that mines HUIS and HAUIs use a single fixed minimum utility threshold based on which HAUIs are identified. In this paper, the proposed algorithm mines HAUIs from transaction databases using Artificial Fish Swarm Algorithm (AFSA) with computed multiple minimum average utility thresholds. Computing the minimum average utility threshold for each item with the AFSA algorithm outperforms other state-of-the-art HAUI mining algorithms with multiple minimum utility thresholds and user-defined single minimum threshold in terms of number of HAUIs. It is observed that the proposed algorithm outperforms well in terms of execution time, number of candidates generated and memory consumption when compared to the state-of-the-art algorithms.
Fault diagnosis in semiconductor manufacturing processes using a CNN-based generative adversarial network1
Authors: Naveen Palanichamy , NithyaSai S. , Udayamoorthy Venkateshkumar , Ashok kumar S.R.
Published: November 2023

In the current industry, quality inspection in semiconductor manufacturing is of immense significance. Significant achievements have been made in fault diagnosis in fabricated semiconductor wafer manufacturing due to the development of machine learning. Since real-time intermediate signals are non-linear and time-varying, the signals undergo various distortions due to changes in equipment, material, and process. This leads to a drastic change in information in intermediate signals. This paper presents a fault diagnosis model for semiconductor manufacturing processes using a generative adversarial network (GAN). The study aims to address the challenges associated with efficient and accurate fault identification in these complex processes. Our approach involves the extraction of relevant components, development of a paired generator model, and implementation of a deep convolutional neural network. Experimental evaluations were conducted using a comprehensive dataset and compared against six existing models. The results demonstrate the superiority of our proposed model, showcasing higher accuracy, specificity, and sensitivity across various shift tasks. This research contributes to the field by introducing a novel approach for fault diagnosis, paving the way for improved process control and product quality in semiconductor manufacturing. Future work will focus on further optimizing the model and extending its applicability to other manufacturing domains.
Research on the impact of digital transformation of energy enterprises on stock price fluctuation
Authors: Sun Qiong , Sun Yu , Jiang Jingjing
Published: November 2023

As an important choice of strategic transformation of energy enterprises, digital transformation has a profound impact on the stock price fluctuation of enterprises. From the perspective of dynamic capacity and environmental regulation, analyzes influences of digital transformation upon energy companies’ share movement volatility, constructs a theoretical model that considers digital transformation and stock price volatility as the primary effects, dynamic capabilities as the mediator, and environmental regulation as the moderator. In addition, the study employs data from China’s A-share listed energy enterprises from 2013 to 2020, utilizing a fixed-effect model to perform an empirical test. The findings demonstrate a significant positive correlation between the digital transformation of energy enterprises and the volatility of stock prices, indicating that the greater the extent of digital transformation, the higher the volatility of enterprise stock prices. Among the dimensions of dynamic capability, only adaptability and innovation ability appears to mediate the relation between digital transformation and stock price fluctuation. Moreover, environmental regulation positively moderates the relationship between digital transformation and the learning ability dimension. Finally, from the macro and micro levels, this study puts forward the policies and supportive measures to stabilize the stock price of energy enterprises, and suggestions on how to implement the digital transformation strategy reasonably according to their own development status and characteristics to provide valuable insights for encouraging the digital transformation among energy firms.
Improved reptile search algorithm with sequential assignment routing based false packet forwarding scheme for source location privacy protection on wireless sensor networks
Authors: Pitchandi@Sankaralingam R. , Arunachalaperumal C. , Mary Anita E.A.
Published: November 2023

Source Location Privacy (SLP) in Wireless Sensor Networks (WSNs) refers to a set of techniques and strategies used to safeguard the anonymity and confidentiality of the locations of sensor nodes (SNs) that are the source of transmitted data within the network. This protection is important in different WSN application areas like environmental monitoring, surveillance, and healthcare systems, where the revelation of the accurate location of SNs can pose security and privacy risks. Therefore, this study presents metaheuristics with sequential assignment routing based false packet forwarding scheme (MSAR-FPFS) for source location privacy protection (SLPP) on WSN. The contributions of the MSAR-FPFS method revolve around enhancing SLP protection in WSNs through the introduction of dual-routing, SAR technique with phantom nodes (PNs), and an optimization algorithm. In the presented MSAR-FPFS method, PNs are used for the rotation of dummy packets using the SAR technique, which helps to prevent the adversary from original data transmission. Next, the MSAR-FPFS technique uses an improved reptile search algorithm (IRSA) for the optimal selection of routes for real packet transmission. Moreover, the IRSA technique computes a fitness function (FF) comprising three parameters namely residual energy (RE), distance to BS (DBS), and node degree (ND). The experimental evaluation of the MSAR-FPFS system was investigated under different factors and the outputs show the promising achievement of the MSAR-FPFS system compared to other existing models.
Deep convolutional neural network for glaucoma detection based on image classification
Authors: Gobinath C. , Gopinath M.P.
Published: November 2023

PURPOSE: Many researchers have found that the improvement in computerised medical imaging has pushed them to their limits in terms of developing automated algorithms for the identification of illness without the need for human participation. The diagnosis of glaucoma, among other eye illnesses, has continued to be one of the most difficult tasks in the area of medicine. Because there are not enough skilled specialists and there are a lot of patients seeking treatment from ophthalmologists, we have been encouraged to build efficient computer-based diagnostic methods that can assist medical professionals in early diagnosis and help reduce the amount of time and effort they spend working on healthy situations. The Optic Disc position is determined with the help of the LoG operator, and a Disc Image map is projected with the help of a U-net architecture by utilising the location and intensity profile of the optic disc. After this, a Generative adversarial network is suggested as a possible solution for segmenting the disc border. In order to verify the performance of the model, a well-defined investigation is carried out on many retinal datasets. The usage of a multi-encoder U-net framework for optic cup segmentation is the second key addition made by this proposed work. This framework greatly outperforms the state-of-the-art in this area. The suggested algorithms have been tested on public standard datasets such as Drishti-GS, Origa, and Refugee, as well as a private community camp-based difficult dataset obtained from the All-India Institute of Medical Sciences (AIIMS), Delhi. All of these datasets have been verified. In conclusion, we have shown some positive outcomes for the detection of diseases. The unique strategy for glaucoma treatment is called ensemble learning, and it combines clinically meaningful characteristics with a deep Convolutional Neural Network.
Study on intentional control strategy of COVID-19
Authors: Wang Kejun , Zhang Hebing
Published: November 2023

With the ongoing evolution of the novel coronavirus pathogen and continuous improvements in our social environment, the mortality rate of COVID-19 is on a decline. In response to this, we introduce an adaptive control strategy known as intentional control, which offers cost-efficiency and superior control effectiveness. The classical SEIR model faces limitations in accurately representing close contacts and sub-close contacts and fails to distinguish their varying levels of infectivity. To address this, our study modifies the classical model by incorporating close contact (E) and a sub-close contact (E2) while reworking the infectious mechanism. Once the model is formulated, we employ various statistical methods to identify crucial parameters, including R2, adjusted R2, and standard deviation. For disease control, we implement an intentional control program with four distinct grades. We develop and apply a scheme in MATLAB for our proposed model, generating diverse simulation results based on realistic parameter values for discussion. Additionally, we explore a range of strategy combinations to differentiate their effectiveness under various social conditions, aiming to identify an optimal approach. Comparing the intentional control strategy to random control, our findings consistently demonstrate the superiority of intentional control across all scenarios. Furthermore, the results indicate that our approach better aligns with the characteristics of the novel coronavirus, characterized by an “extremely low fatality rate and strong infectivity,” while offering detailed insights into the transmission dynamics among different compartments.
Governmental support measures to maintain the working capacity of people with multiple sclerosis
Authors: Eberharter Mona-Elisa , Stummer Harald
Published: November 2023

BACKGROUND: Multiple sclerosis (MS) is a chronic inflammation of the central nervous system that can result in cognitive and physical deficits. It can lead to early retirement in 50% of the cases in the first 15 years of the disease without governmental support and to date, there are only a few studies which focus on measures to support people with MS at the workplace. OBJECTIVE: The aim of this study is to analyse the governmental support measures to maintain the working capacity of people with MS and to provide improvements and further approaches for their support. METHODS: A two-stage study was conducted by means of qualitative interviews. The first study was conducted using the problem-centred form with 10 experts from the health and social care sector who work with people affected by MS. The second study was conducted using qualitative interviews in biographical form with 20 people suffering from MS. RESULTS: The study participants mentioned various suggestions for improving the existing governmental support measures, such as a central support office for illness-related questions, relaxing the strict requirements for support measures, giving the regulation of support measures to federal government, changing the pension system and providing financial support for individual therapies and outpatient therapies. Currently, MS patients lack knowledge about contact persons for MS-specific questions, as well as intensive cooperation between labour market service, health service providers and companies to help find a job. CONCLUSION: A combination of the governmental support measures available so far with the proposed optimisations or additions by MS patients and experts can lead to a significant reduction in disease-specific absences and limitations, which in turn results in the preservation of the ability to work. All suggestions from the interviews need to be explored further to investigate a possible implementation.
Evaluating compliance with COVID-19 social distancing protocol in a university in the south-east of Nigeria using radio frequency identification
Authors: Eli-Chukwu Ngozi C. , Nmadu Daniel , Uma Uma U. , Eheduru Marcellinus I. , Ogah Ogah E. , Emeh Jerryson C.
Published: November 2023

The 2019 coronavirus pandemic is considered a global health emergency and the greatest challenge human kind has faced since World War II. The disease has claimed many lives globally and has caused major economic deterioration. The most challenging is the constant change of the virus through mutations leading to emergence of different variants. There are stipulated measures to mitigate the spread of this virus amongst which social distancing protocol seems to be the most effective. This study measures compliance with COVID-19 social distancing protocol using Radio Frequency Identification in a university in Southeastern Nigeria. The result reveals low indicators of compliance with the social distancing precautionary measures. The results from different faculties indicate that the students did not comply, with an average compliance of 24 percent. The study contributes to present and future pandemic management as the rate at which the virus spreads despite the precautionary measures were alarming. Hence the need to measure compliance in real time rather than adopting an abstract method in a critical situation of this nature.
Using semantic story maps to describe a territory beyond its map
Authors: Bartalesi Valentina , Coro Gianpaolo , Lenzi Emanuele , Pratelli Nicolò , Pagano Pasquale , Felici Francesco , Moretti Michele , Brunori Gianluca
Published: November 2023

The paper presents the Story Map Building and Visualizing Tool (SMBVT) that allows users to create story maps within a collaborative environment and a usable Web interface. It is entirely open-source and published as a free-to-use solution. It uses Semantic Web technologies in the back-end system to represent stories through a reference ontology for representing narratives. It builds up a user-shared semantic knowledge base that automatically interconnects all stories and seamlessly enables collaborative story building. Finally, it operates within an Open-Science oriented e-Infrastructure, which enables data and information sharing within communities of narrators, and adds multi-tenancy, multi-user, security, and access-control facilities. SMBVT represents narratives as a network of spatiotemporal events related by semantic relations and standardizes the event descriptions by assigning internationalized resource identifiers (IRIs) to the event components, i.e., the entities that take part in the event (e.g., persons, objects, places, concepts). The tool automatically saves the collected knowledge as a Web Ontology Language (OWL) graph and openly publishes it as Linked Open Data. This feature allows connecting the story events to other knowledge bases. To evaluate and demonstrate our tool, we used it to describe the Apuan Alps territory in Tuscany (Italy). Based on a user-test evaluation, we assessed the tool’s effectiveness at building story maps and the ability of the produced story to describe the territory beyond the map.
Occupational therapists’ perceptions of the feasibility of using tele-assessment for remote prescription of assistive devices in Singapore: A qualitative study
Authors: Poh Jess Xiu Yi , Chan Kuang Hong , Tan Samantha Si Li , Xu Tianma
Published: November 2023

BACKGROUND: Occupational therapists (OT) assess and prescribe assistive devices to older adults with limitations in performing daily living activities. Timely prescription of assistive devices to accommodate the rising demand has been affected by the COVID-19 pandemic. Tele-assessment allows for continuity of care, but its success depends on therapists’ acceptance. OBJECTIVE: This study examined OTs’ perceptions of the feasibility of conducting tele-assessment and developing a clinical practice guideline for remote prescription of assistive devices for older adults in Singapore. METHODS: Eligible OTs were recruited from purposive sampling. Semi-structured interviews were conducted via a virtual platform (Zoom). Audio recordings were transcribed verbatim. Inductive thematic analysis using a line-by-line coding method was used to identify common trends. RESULTS: Interviews with 10 participants revealed three main themes: (1) therapists’ perceptions of the feasibility of tele-assessment, (2) criteria for safe and appropriate prescription of assistive devices via tele-assessment, and (3) practical considerations for the implementation of tele-assessment. Participants felt that tele-assessment increases efficiency with more older adults being more receptive towards technology. They also raised suggestions to address OTs’ concerns regarding the safety and accuracy prescription of assistive devices following tele-assessment. This included establishing the client’s suitability for assistive device prescription, characteristics of assistive devices, resources required, and considering the preferences of stakeholders involved. CONCLUSION: Tele-assessment for assistive device prescription by OTs appears feasible in Singapore. OTs should consider collaborating with other stakeholders to develop a tele-assessment clinical practice guideline for assistive device prescription. Further studies testing its clinical effectiveness during and/or post-pandemic are warranted.
ACCOMPLISHMENT OF COMPLEX OF ABLUTION OF BLAST FURNACES AT PC INJECTION AND USAGE OF CHARGE MATERIALS OF VARIABLE QUALITY
Authors: SEMENOV YU. S. , GORUPAKHA V. V. , VASHCHENKO S. V. , KHUDYAKOV A. YU. , SHUMEL’CHIK E. I.
Published: November 2023

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
STUDY OF COMPOSITION AND STRUCTURE OF NLMK BF No. 6 HEARTH SCULL. Report 2
Authors: KURUNOV I. F. , BLIZNYUKOV A. S. , LOGVINOV N. V. , TIKHONOV D. N. , SADRADINOV M. R. , MAKAVETSKAS А. R. , FISHCHENKO YU. YU.
Published: November 2023

Resistance of hearth walls lining and their joint with hearth plug considerably governs a blast furnace (BF) campaign duration. Development of hearth design of modern BFs provides a high effective heat sink by copper cooling plates and application for the lining carbonaceous blocks having high heat conductivity, which causes stable scull formation. Study of the composition and the structure of the scull is an important and actual task to provide the highest technical and economical indices of blast furnace production, increasing of the furnaces campaign duration. It was shown that the scull in the hearth zone has a laminated structure. It was established that content of titanium compounds (oxide, carbides and nitrides) in the scull is low. Zinc buildups were not found on the carbonaceous refractories of the hearth walls lower the tap hole. Considerable content of zinc compounds was revealed in the scull of brickwork of the hearth top, in the area of tap holes and hole channels, on the hearth refractories. It was found that basic components of the scull were represented by carbon in the form of graphite, metal (mainly in the form of α-Fe) and slag, amount of which was nincreasing from the lower part of the hearth to the upper one while the content of metal and graphite in it was decreasing.
EFFECT OF METALLIZED FINES OVERLOADING OPERATIONS ON THEIR SECONDARY OXIDATION
Authors: TIMOFEEVA A. S. , КОZHUKHOV А. А. , NIKITCHENKO Т. V.
Published: November 2023

During transportation of a metallized product, formation of fines takes place caused by the product crushing and abrasion. The fines formed are subjected to accelerated oxidation, effecting the oxidation of the whole metallized product. The study was aimed at factors determination, intensifying the secondary oxidation of the metallized fines. Results of the study of secondary oxidation of metallized fines depending on their grain size distribution and caking presented. Experiments of 11 days duration with the metallized fines of three various grain size distribution classes were carried out. The metallized fines for the studies were taken from a cooling conveyer of hot briquetted iron before screening and divided by a vibration granulator into classes +10‒25 mm; +5‒10 mm; ‒5 mm. Calculations of reaction ability were accomplished based on calculation of absorbed oxygen by the metallized fines. It was
established that the growth of the metallized product secondary oxidation rate takes place due to increasing of the metallized fines share at increasing number of overloading operations. It was noted that their oxidation particularly increases at the mixing of class ‒5 mm in the process of overloading. The reaction ability of the class of the fines at the overloading increased by 4 times comparing with fines not overloaded. The fines of class +10‒25 mm had the lowest reaction ability comparing with fines of other classes. It is explained by the fact that oxygen free access to the particles of class of fines +10‒25 mm is less comparing with the rest, since the specific surface of this class of fines is less than that of the rest. It was recommended to arrange the transportation of the hot-briquetted iron in such a way to have overloading operations as less as possible, decreasing in average the secondary oxidation of the whole metallized product.
STUDY OF MICROTOPOGRAPHY OF FREE SURFACE OF IF-STEEL AT THE UNIAXIAL STRETCHING
Authors: BELOV V. K. , GUBAREV E. V. , KRIVKO O. V. , BEGLETSOV D. O.
Published: November 2023

Study of the process of final microtopography of automobile-body sheet surface forming revealed increase of roughness of free surface of sheet at its uniaxial deformation. A necessity to account this factor was noted, since the regulation ranges of microtopography parameters of some kinds of sheet products are narrow. Results of the study of variation of microtopography surface of automobile-body sheet of IF-steel depending on grain size and value of uniaxial deformation presented. It was shown that with the growth of ε, a complicated character of forming of free surface microtopography at various scale levels is observed. Amplitude values (Ra, Rq) and step (Rрc) parameters increase in a nonlinear way when ε grows for high frequency component of microtopography. While ε grows, on the surface of IF steel the grains form structural elements of deformation (SED). The step parameters of SED increase while ε grows slightly, whereas the amplitude parameters of SED show considerable growth. Stages of variation of surface microtopography of IF-steel at uniaxial stretching considered. It was shown that at early stages of deformation, intensive formation of ledges of micro-asperity of rough layer and forming of SED boundaries on the surface takes place. During next stages of deformation, the process of spatial decomposition of the roughness profile asperities at the constant spatial parameters of SED takes place. The intensity of growth of the rough layer roughness heights decreases and that of growth of height sizes of SED increases. At the stages close to destruction, the roughness profile is becoming even and the amplitude characteristics are increasing sharply. The amplitude characteristics of SED profile Raгарм considerably exceed the analogue characteristics of the roughness profile Raслуч.The results of the study should be used to take into consideration formation of free surface microtopography during production of cold-rolled sheet.
THERMODYNAMIC ASPECTS OF OXIDES REDUCING BY ALUMINUM AND TITANIUM AT THE THERMIT WELDING OF RAILS
Authors: BENDRE YU. V. , GORYUSHKIN V. F. , KOZYREV N. A. , SHEVCHENKO R. A. , OZNOBIKHINA N. V.
Published: November 2023

During aluminothermic welding of rails, formation of aluminum oxides can take place, which become centers of residual stresses forming resulting in cracks formation followed by fracture and destruction of the welding joint. It was proposed to add titanium scrap in the form of preliminary made powders to the welding thermites composition. At the replacement of aluminum by titanium, titanium oxides formation takes place providing higher resistance against cracks formation. Comparative estimation of thermodynamic properties [∆rH°(T), ∆rG°(T)] of thermite reactions with aluminum and titanium in the systems metal oxide – aluminum and metal oxide – titanium under standard conditions presented. As reaction components for calculation of thermodynamic properties, oxides of iron, manganese, silicon and chrome were used. Thermodynamic analysis of 6 reactions with aluminum and 30 reactions with titanium were carried out. It was established that all the reactions under consideration are thermodynamically probable. However, reactions of both aluminum and titanium with iron oxides had the highest probability and correspondently the highest heat generation. Reducing of silicon oxide had the lowest probability and correspondently the lowest heat generation. The reaction with oxides of manganese and chrome had an intermediate position. By the reducing ability titanium is not worse than aluminum and in reactions with iron oxide even exceeds it, particularly in the temperature range over 2000 K. Enthalpies of reducing reactions of iron oxide by titanium is in the same area of values as the enthalpies of reaction of reducing by aluminum. A thermodynamic analysis showed that application of titanium as a reducing agent at the thermit welding is quite acceptable along with aluminum.
BEHAVIORS OF OXIDATION AND DECARBURIZATION ON SURFACE OF HIGH-CARBON STEEL WIRE RODS
Authors: PIVOVAROVA K. G.
Published: November 2023

The quality of high-carbon wire rods is subject to high requirements in terms of the size of the decarbonized layer, the amount and composition of the scale formed by the interaction of the oxidizing furnace atmosphere with the surface of steel. In this connection, studies of the kinetics of high-temperature oxidation of high-carbon steel are of great practical importance, both in the development of new and adjustment of existing modes of heat treatment of steel. The results of experimental studies of hightemperature oxidation and decarburization of the surface of high-carbon steel grade 80P on the synchronous thermal analysis device STA 449 F3 Jupiter presented. Temperature intervals of intensification of scale formation and decarburization of the surface in various media (weakly oxidizing and oxidizing) have been established. Phase transformations in high-carbon steel grade 80P have been studied by differential scanning calorimetry and the temperatures of the beginning and end of the formation of homogeneous austenite during heating have been established. It was noted that in the range of heating temperatures of steel 720‒950°C, along with phase transformations, the intensification of the processes of scale formation and depletion of the surface layers with carbon begins. The
exponential dependence of steel loss on the heating temperature of the sample was obtained by thermogravimetric analysis. It was shown that the oxidation rate of the surface increases by 3 times with an increase in the temperature of the workpiece from 900 to 1000°C, and up to 1200°C ‒ by 8 times. It was noted that the temperature at which the oxidation rate of steel is minimal in the temperature range from 900 to 1000 °C is about 929 °C, in the range of 1100‒1250°C ‒ 1157°C. The obtained results can be used to select the main technological parameters of the heat treatment mode of wire rods made of 80P steel, which ensure the formation of a
minimum amount of easily removed scale on the metal surface.
ASSESSMENT OF THE ECOLOGICAL STATE OF SNOW AND SOIL COVERINGS WITHIN THE BORDERS OF THE SANITARY PROTECTION ZONE OF EVRAZ ZSMK JSC
Authors: ZAKHAROVA М. А. , VODOLEEB А. S. , ANDREEVA O. S. , DOMNIN K. I.
Published: November 2023

When assessing the impact of large industrial enterprises on the environment, it is important to take into account the consequences of negative impact on all components of nature. The results of the study of the influence of industrial emissions into the atmospheric air on the state of snow and soil covering within the boundaries of the sanitary protection zone (SPZ) of the metallurgical plant JSC EVRAZ ZSMK are presented. The results of the chemical analysis of snow water showed that at all sites the dry residue in the melt water is 7‒8 times lower than the MPC, and the content of chloride ions does not exceed the MPC. The content of sulfate ions at one of the sites is 2 times lower than the MPC, at the rest ‒ below the detection limit. The content of heavy metals and arsenic in the soil at the SPZ test plots does not exceed the MPC. Soil analysis showed that the values of active acidity (pH of the water extract) are in the range of 6.30‒7.40 units, which indicates the absence of technogenic soil acidification. The content of petroleum products in the selected samples is below the threshold value, which makes it possible to classify the soils at all sites of the SPZ of JSC EVRAZ ZSMK for this compound as conditionally clean. The content of benz(a)pyrene in the soil at experimental plots, except for one, does not exceed the MPC values. The sulfur content does not exceed the MPC values at all test plots of the SPZ.
GAS DYNAMIC ANALYSIS OF THE SINTER CHARGE IGNITION PROCESS
Authors: FROLOV YU. A. , KAPLUN L. I. , CHUKIN D. M.
Published: November 2023

To increase the productivity of sintering machines, sinter quality and economy of the gaseous fuel, it is necessary to ensure the optimal mode of external heating of sintering charge layer. The effect of sintering machine vacuum chamber throttling under the ignition hearth on the gas-dynamic mode of charge ignition and sintering, including the quality of sinter, sintering machine productivity, gas consumption for the charge ignition and the possibility to control and manage the charge humidity were considered. It is shown, that throttling of the first vacuum chambers allows reduction in the fuel consumption, charge shrinkage, amount of air suction into the ignition hearth and gas-discharge duct of the sintering machine and improvement of the sinter quality. The effects of air rarefaction on charge layer surface temperature and sinter quality are provided. The structural variants of vacuum chamber throttling implemented in practice are presented; two of them operate at sintering machines at Bhilai Iron and Steel Works, India. It is shown that throttling of the first vacuum chambers located under ignition hearth is effective for charge ignition and sintering processes in all cases and should be obligatory during the sinter production.
DEVELOPMENT OF OPTIMUM TECHNOLOGY REGIMES FOR PROCESSING TITANOMAGNETITE CONCENTRATES IN THE JEP UNIT
Authors: RYBENKO I. A. , TSYMBAL V. P. , SECHENOV P. A.
Published: November 2023

For separation of titanium oxides into slag phase the electric arc furnaces are used in the existing technological schemes. A cheaper waste-free technology for processing titanium concentrate based on a continuous metallurgical jet-emulsion process (JEP) and unit was proposed. The following technological features of the new continuous metallurgical process JEP were considered: creation of a large reaction surface with subsequent organization of the forced movement of the formed gas suspension under pressure; implementation of the principle of gas-dynamic locking of the output channel in an oscillator reactor developed on the basis of this idea; creation of a non-equilibrium stationary oscillatory mode at a given pressure level; bottom supply of a two-phase working mixture prepared in an oscillator reactor to a vertical column reactor. The possibility of implementing a waste-free technology for processing titanomagnetite concentrates was substantiated, that simultaneously ensures the production of commercial titanium slag with smelting of the naturally alloyed metal. It was shown that the technology of almost complete separation of the iron-containing and titanium-containing components from titanium-magnetite concentrate is possible to implement in the JEP type unit in order to obtain the titanium slag with Ti2O5 content 46 % or more. The optimal consumption of materials was determined for complete reduction of iron and conversion of the titanium oxides into slag without formation of carbides.
IMPLEMENTATION OF THE NEW APPROACHES TO PRODUCTION OF HIGH-QUALITY ROLLED METAL FOR ENAMELING
Authors: CHIKISHEV D. N. , GOLUBCHIK E. M. , NIKITENKO О. A. , SHIRYAEVA E. N. , KOLYADA T. V.
Published: November 2023

Consumers of cold-rolled steel for enamelling are standardizing the indicators that exclude the occurrence of the “fish scale” defect in the finished product. In the domestic practice the hydrogen embrittlement index (HEI) is considered to be the index characterizing the tendency of rolled products to formation of the mentioned defect. The threshold values of HEI are determined by the domestic standards and normative documents. The existing method of HEI determination has a number of essential drawbacks, and the values received on its basis do not always objectively reflect the tendency of the rolled metal to form the defect “fish scale”. A new indicator the volume fraction of structurally free cementite, which correlates with a sufficiently high degree of the HEI value, has been proposed. A method allowing establishment of the tendency of the rolled metal to appearance of the “fish scale” defect on enamelled products has been presented. It is shown that the microstructure of the low-carbon steel for enameling with low cementite content significantly influences the mechanism of the “fish scale” defect formation and it is closely connected with the HEI. The presence of a considerable amount of cementite globules allows (all other things being equal) increase in the capture and retention of the surface hydrogen which occurs during the enameling process. It is noted that the testing of the rolled metal corresponds to the normative documents if the volume fraction of the structurally free cementite is 2.7 % and more. The technological modes of the hot rolling were developed for the most widespread steel grade utilized for enameling 08ЮР (Russian Standard), that provides the high values of volume fraction of cementite in microstructure. The temperature of final stage of hot rolling depending on thickness of finished rolled product was in the range of 860‒890 °С; the temperature of coiling was not lower than 740 °С. It was found that apart from the temperature conditions of the process, the significant factor is the speed parameters of rolling and stripping, as well as cooling mode on the diverting roller conveyor of the hot-rolling mill. A new cooling mode on the diverting mill was proposed and adapted to the mill model.
PREDICTION OF THE TENSILE STRENGTH OF STEEL FORGINGS
Authors: ORLOV G. A.
Published: November 2023

Great attention is paid to the issues of improving the methods of product quality prediction, in particular, a comprehensive approach to its evaluation is being developed based on the principles of qualimetry. The example of experimental approach is provided to predict one of the mechanical properties ‒ tensile strength which is an important indicator of the steel forgings quality. The investigation has been carried out to estimate the accumulated strain degree, chemical composition, friction conditions at contact surface influencing on temporal resistance distribution in the forging volume. The accumulation of strain degree was carried out by crimping of cubic billets in three mutually perpendicular directions with different number of crimping cycles according to cube‒cube scheme. The distribution of strain degree over the volume of a deformed billet was experimentally determined for lead samples by coordinate grid technique. The lead cubic billets were cut in half. A square grid was applied to one of the halves, and then the halves were fused with a fusible Wood alloy and subjected to the first upsetting. After upsetting the sample was unsoldered and the Λ value in each cell was calculated from the curvature of the coordinate grid. The forging of steel billets was carried out in a similar way. After forging the steel billets, the specimens were cut out for mechanical testing. As a result of experimental data processing, the equation of regression has been received, which enables to predict the level of forgings’ tensile strength at the known technological parameters. Significance of the coefficients of the obtained equation was validated by the Student's criterion and the adequacy by the Fisher's criterion. The developed technique can be applied for selection of rational mode of deformation during forging for maintenance of the given level of mechanical properties.
STUDY OF THE WELDABILITY OF STEELS OF DIFFERENT ALLOYING COMPOSITIONS FOR THE LARGE-DIAMETER PIPES TRANSPORTING HYDROGEN SULPHIDE-CONTAINING GAS
Authors: KUDASHOV D. V. , STEPANOV P. P. , VOLKOVA E. A. , EFRON L. I. , ZHARKOV S. V. , SMETANIN K. S. , BARANOVA O. A.
Published: November 2023

Increased resistance to brittle fracture in any zone of the welded joint is one of the main requirements for quality of steel pipes for transportation of the hydrogen sulphide gas, which determines the relevance of identification of the reasons of the impact toughness decrease of the welded joint area. The purpose of the study was to investigate the microstructure formation features of the seam zone of pipes made of low-carbon steels of different chemical composition. The effect of microstructure of the coarse-grained area of the heat affected zone on toughness of welded joint has been estimated by the laboratory thermal cycling testing complex Gleeble 3180. The samples with cross-section of 10×10×110 mm made of commercially available steel grades 04ХНДБ, 06ГНФБ and 05ХГБ (Russian Standard) with different contents of niobium and manganese were used as material for the research. To eliminate the effect of heating rate and holding time in austenitic region on the microstructure, the simulation was carried out in a cyclic mode with the same heating rate up to 1350 °С and subsequent cooling to 800 °С. The cooling rate in the interval 800–500 °C varied from 2 to 64 °C/s. The microstructure formation of the seam zone was studied by scanning electron microscopy and reflected electron diffraction. Despite the differences in chemical composition, the studied steels showed similar microstructure after simulation of the coarse-grained area of the heat-affected zone. For all the steels an increase in the share of rack bainite and the density of high angle boundaries with increasing cooling rate was found. It was established that at close values of average grain size of ferrite in the samples from steel 04ХНДБ the grain homogeneity is higher due to decrease in size and quantity of the largest grains. In specimens made of 05ХГБ and 06ГНФБ steel grades, the impact toughness of simulated coarse-grained area of the heat affected zone stabilizes at high level due to formation of more favorable dispersed structure when cooling rate increases more than 8 °C/s.
MODELLING OF THE MANDREL-FREE COIL DRAWING PROCESS OF PIPES FROM STEEL 12Х18Н10Т
Authors: LOGINOV YU. N. , KOSMATSKII Ya. I. , BUSHUEVA N. I. , BUVAEV D. N.
Published: November 2023

The metallurgical industry of Russia faces the task of joining the country with the world leaders in the production of liquefied natural gas (LNG). This task involves reducing the dependence of the level of imports, since today the dependence on imports in the LNG production industry is about 95 %. The main equipment for LNG production is a spiral heat exchanger. The purpose of this work was to study the thin-walled long-length pipes used in its construction. According to the requirements for the specified heat exchange equipment, the components of its cold-deformed pipes must have a length of at least 50 m. For the production of such pipes, it is recommended to apply the mandrel-free coil drawing process. The article presents the results of a theoretical study of the mandrel-free coil drawing process of pipes from steel AISI 321 (grade Cr18Ni10Ti). Predicting the technological feasibility of manufacturing pipes in coils can reduce the costs for subsequent organization of industrial production. Using the finite element method implemented in the “Deform-2D” software package, the boundary value problem was solved to carry out the process of mandrel-free coil drawing of pipes and the process of their winding on a drum. The simulation was carried out for the technology of manufacturing seamless cold-deformed pipes in accordance with the principal scheme of coil production ensuring its rational organization, which was developed by the research & production teams of the TMK Group. The possibility of manufacturing pipes in coils with dimensions of 10×1.0 mm from steel grade AISI 321 (grade Cr18Ni10Ti) has been theoretically justified. It is recommended to use the simulation results for the subsequent implementation of the technology.
MINIMIZATION OF DEFECT IN THE FORM OF LONGITUDINAL FOLDS AT THE END SECTIONS OF THIN-WALLED SEAMLESS PIPES DURING ROLLING AT AUTOMATIC MILL
Authors: SHERBUTAEV N. I. , GONCHARUK A. V. , ISKHAKOV R. V. , STARICHKOVA O. V.
Published: November 2023

During rolling of thin-walled seamless pipes at the rear ends, a defect in the form of end folds occurs, which leads to an increase in the consumption coefficient of the metal. To identify the causes of the formation of this defect, the mathematical modeling of rolling processes in the QForm VX software was carried out. The simulation results showed that the main factor in the formation of end folds at the rear ends of the pipe billets is an increased relative compression along the wall of the pipe billet in the first pass, which leads to flattening of the rear end of the pipe billet and formation of longitudinal folds. To prevent the formation of end folds, it is proposed to install an additional sleeve with a mandrel. As a result of the research, the values of relative compressions were determined, at which a defect is formed for rolling with a new mandrel installation option. It was found that with relative compression along the wall in the first passage from 30.0 %, a defect in the form of folds (“fins”) at the rear end of the pipe billet is formed. With a relative compression of the wall in the first passage up to 39.4 %, the installation of sleeves reduces the formation of “fin” defects at the rear end of the pipe billet; with a relative compression from 39.4 % to 41.8 %, its installation does not prevent the formation of these defects. The optimal distance between the mandrel of the automatic mill and the sleeve is 20–30 mm
INFLUENCE OF TRANSSHIPMENT OF HOT-BRIQUETTED IRON DURING TRANSPORTATION ON ITS REACTIVITY
Authors: TIMOFEEVA A. S. , KOZHUKHOV A. A. , NIKITCHENKO T. V. , KOROTKOVA L. N.
Published: November 2023

During the transportation of hot-briquetted iron (HBI), the metallized product undergoes secondary oxidation, which negatively affects its metallurgical properties. In the course of research, the influence of the strength of HBI on the oxidation process of the metallized product was established. To determine the change in the physical characteristics of briquettes during their destruction, a simulation of mechanical effects in the processes of transshipment during transportation from the manufacturer to the port of loading was carried out. A general view of the installation for simulating transshipment during transportation of HBI is given. The briquettes were dropped from a height of 2, 2‒4 and 6 m to simulate their fall from a height, respectively, into a railway car when loaded at the sender's station, the opening of the grab when unloading to the site of an open warehouse and the opening of the grab when loading into the hold of the vessel. A histogram of the percentage destruction of briquettes depending on the height of the discharge is given. The reactivity of various fractions of HBI has been determined. It is shown that the reactivity of the metallized product increases when the size of the briquette fraction decreases, and it depends on the specific surface area and porosity of the material, temperature and humidity of the environment. With insufficient strength during transportation, the briquettes are destroyed, as a result their oxidation process is accelerated, since the reactivity of halves and small pieces of the destroyed briquettes is higher by 60% and 76%, respectively, than the whole ones. It is recommended to reduce the reactivity, and hence the rate of secondary oxidation of the metallized product, by optimizing the number of transshipments and the heights from which they are carried out. It is advisable to reduce the height of transshipment to 1.5 m, and pay attention to the strength of the briquettes after pressing