Smelting Research Articles

Evaluation of atmospheric particulate matter pollution characteristics in Shanghai based on biomagnetic monitoring technology

Atmospheric particulate matter (PM) pollution is one of the world's most serious environmental challenges, and it poses a significant threat to environmental quality and human health. Biomagnetic monitoring of PM has great potential to improve spatial resolution and provide alternative indicators for large area measurements, with respect and complementary to standard air quality monitoring stations. In this study, 160 samples of evergreen plant leaves were collected from park green spaces within five different functional areas of Shanghai. Magnetic properties were investigated to understand the extent and nature of particulate pollution and the possible sources, and to assess the suitability of various plant leaves for urban particulate pollution monitoring. The results showed that magnetic particles of the plant leaf-adherent PM were predominantly composed of pseudo-single domain (PSD) and multi-domain (MD) ferrimagnetic particles. Magnolia grandiflora, as a large evergreen arbor with robust PM retention capabilities, proved to be a more suitable candidate for monitoring urban particulate pollution compared to Osmanthus fragrans, a small evergreen arbor, and Aucuba japonica Thunb. var. variegata and Photinia serratifolia, evergreen shrubs. Meanwhile, there were significant differences in the spatial distribution of the magnetic particle content and heavy metal enrichment of the samples, mainly showing regional variations of industrial area > traffic area > commercial area > residential area > clean area. Additionally, the combination with the results of scanning electron microscopy, shows that industrial production (metal smelting, coal burning), transport and other activities are the main sources of particulate pollution. Plant leaves can be used as an effective tool for urban particulate pollution monitoring and assessment of atmospheric particulate pollution characteristics, and the technique provided useful information on particle size, mineralogy and possible sources.

Kesan Tanpa Masa Pegangan Rawatan Haba ke Atas Sifat Mekanikal dan Mikrostruktur Pembuatan Aditif Aloi Titanum (Ti6Al4V) Melalui Proses Peleburan Laser Selektif (SLM)

Additive manufacturing (AM) or better known as 3D printing is a manufacturing method based on powder metallurgy technology that is able to produce a 3D component. Selective laser melting (SLM) is one of the AM methods capable of producing metal 3D components, however, residual stresses are often produced in such component due to repeated melting and solidification of metal during the printing process. The residual stresses can deteriorate the performance of the 3D components’ mechanical properties if not removed or reduced. Heat treatment processes are often used to remove the residual stresses. The basic parameters of heat treatment are heating temperature, heating rate, cooling rate and holding time. Based on the basic parameters, the effect of holding time in heat treatment is still less reported for 3D components printed via SLM. Therefore, in this study, the effect of holding time on the mechanical properties and microstructure of 3D titanium alloy (Ti6Al4V) components was intestigated. A total of 9 sets of cubic samples were printed on different processing parameters such as laser power (225W, 275W, 325W), scanning speed (800mm/s, 1100mm/s, 1400 mm/s), layer height (0.3mm) and hatching distance (0.10mm, 0.12mm, 0.14mm ). It was found that hardness of 383 - 448 HV was obtained where samples P3, P9 and P5 gave the highest, medium and lowest hardness values. Based on the microstructure observation, α + β phase and martensite structures are produced due to the vanadium content of 4% and heat treated at 935°C. A critical review was also studied to compare previous studies that used different holding times on SLM-printed Ti6Al4V 3D components. It was found that different holding times did not have a significant effect on the mechanical properties of Ti6Al4V 3D components where the outcome of previous studies alligns with that of from this study. In addition, past works have also reported that heat treatment is able to lower the residual stresses in SLM-printed Ti6Al4V 3D components. Finally, the effectiveness of heat treatment in reducing the residual stresses in SLM-printed Ti6Al4V 3D components at different printing parameters should also be studied to understand the mechanism of microstructural changes during and after heat treatment.

Механизм влияния электрического поля на процесс модифицирования серого чугуна

A diagram of an experimental installation for measuring the electrical resistance of a gray cast iron melt is presented, where a gauge based on a Kelvin double bridge is used. It is shown that the value of the specific electrical resistance of gray cast iron varies depending on the type of conditioning agent. Experimental data on the difference in specific resistivity values for various gray cast iron nucleating agents are presented. Changes in the values of electrical resistance under the influence of electric field treatment of inoculated cast iron melt are also given. Comparison of the strength values of gray cast iron with its values of the electrical resistivity of the cast iron melt after the electrical field exposure showed their simultaneous change. The decrease in the values of the electrical resistance of hot iron due to the electric field exposure is shown and it corresponds to an increment in the strength of inoculated cast iron. The effectiveness of the electric field exposure on the process of inoculation is determined by thermal ionization of the chemical elements included in the conditioning agent. The maximum increase of these parameters after electric field exposure when using FS75 nucleating agent is shown. The mechanism of the influence of an electric field on the cast iron solidification for the inoculation process of FS75, containing 75 % silicon in its composition, is described. The dependence of the efficiency of electric field exposure on the composition of the nucleating agent for gray cast iron is shown. A physical model of the effect of an electric field exposure on the process of cast iron inoculation is found. The possibility of influencing the hydrodynamic situation in the melt of gray cast iron and changing the rate of dissolution of nucleating agent particles by means of electric field exposure is given

Literature study: Comparative analysis of lead content in blood between spot workers, Caroseries industry workers, and metal smelting industry workers

Introduction: This study aims to analyze the comparison of lead content in blood between gas station attendants, bodywork industry workers, and metal smelting industry workers. Lead (Pb) is a heavy metal that can have dangerous effects on human health. Lead exposure can occur through various sources, including the work environment. Method: The research used is a literature study by collecting articles published between 2013-2023. After selection, there were 18 articles that were relevant to the research topic. Results and Discussion: The average lead content in the blood of gas station attendants ranges from 2.75 μg/dL to 35,317 μg/dL, bodywork industry workers range from 14.4 μg/dL to 35 μg/dL, and metal smelting industry workers range from 14.4 μg/dL. dL up to 50.83 μg/dL. Differences in levels of lead exposure between these three professions can be caused by differences in type of work, activities and work environment. Conclusion: Based on the results of this research, it can be concluded that gas station officers, bodywork industry workers, and metal smelting industry workers have different levels of exposure to lead. Therefore, appropriate health protection, such as the use of PPE and safe work practices, needs to be implemented to reduce the risk of lead exposure.

An experimental study on the impact of particle surface wettability on melt infiltration in particulate beds

Melt infiltration into porous media is an intriguing phenomenon that holds immense significance across various sciences and technologies. In this work, the problem of metallic melt infiltration in particulate beds is investigated for understanding and prediction of severe accident progression associated with a molten pool penetrating through an underlying debris bed which may form in the reactor core or in the lower head of a light water reactor.The present study aims to quantify the effect of particle surface’s wettability on melt infiltration kinetics. For this purpose, two categories of experiment are conceived and carried out to measure the wettability of different material surfaces by melt and to characterize melt infiltration kinetics in one-dimensional particulate beds, respectively. The melt material is tin–bismuth eutectic alloy with a melting point of 139 °C. Copper (Cu), stainless steel (SS), Tin (Sn) and tin-coated stainless steel (Sn-coated SS) are chosen as materials of substrates and particles in wettability measurement and melt infiltration study. The particulate beds, packed with 1.5 mm spheres, are preheated to 200 °C before the melt infiltration begins.The experimental data of wettability measurement shows that the contact angles of liquid Sn-Bi eutectic on the above-mentioned material surfaces range from 79° to 135°. The results of melt infiltration tests confirm the significant effect of wettability on melt penetration kinetics. The capillary force plays a significant role in the initial infiltration of particulate beds. Specifically, a wettable particulate bed enhances the initial melt infiltration, whereas non-wettable beds hinder it.

Mechanism of efficient adsorption for arsenic in aqueous solution by zeolitic imidazolate framework‑8.

Arsenic (As) is one extremely hazardous and carcinogenic metalloid element. Due to mining, metal smelting, and other human activities, the pollution of water (especially groundwater) and soil caused by As is increasingly serious, which badly threatens the environment and human health. In this study, a zeolite imidazolate framework (ZIF-8) was synthesized at room temperature and employed as an adsorbent to facilitate the adsorption of As(III) and As(V) from the solution. The successful synthesis of ZIF-8 was demonstrated by X-ray diffraction (XRD), and scanning electron microscopy (SEM) revealed that its particle size was approximately 80nm. The adsorption kinetics, adsorption isotherm, solution pH, dose, coexisting ions, and the synonymous elements antimony (Sb) were conducted to study the adsorption of As by ZIF-8 nanoparticles. The maximum saturation adsorption capacity was determined to be 101.47mg/g and 81.40mg/g for As(III), and As(V) at initial pH = 7.0, respectively. Apparently, ZIF-8 had a good removal effect on As, and it still maintained a good performance after four cycles. The coexisting ions PO43- and CO32- inhibited the adsorption of both As(III) and As(V). ZIF-8 performed well in removing both As and Sb simultaneously, although the presence of Sb hindered the adsorption of both As(III) and As(V). Both FTIR and XPS indicated the adsorption mechanism of As on ZIF-8: ZIF-8 generates a large amount of Zn-OH on the surface through hydrolysis and partial fracture of Zn-N, both of which form surface complexes with As.

Structural pathways for ultrafast melting of optically excited thin polycrystalline Palladium films

Due to its extremely short timescale, the non-equilibrium melting of metals is exceptionally difficult to probe experimentally. The knowledge of melting mechanisms is thus based mainly on the results of theoretical predictions. This work reports on the investigation of ultrafast melting of thin polycrystalline Pd films studied by optical laser pump – X-ray free-electron laser probe experiments and molecular-dynamics simulations. By acquiring X-ray diffraction snapshots with sub-picosecond resolution, we capture the sample's atomic structure during its transition from the crystalline to the liquid state. Bridging the timescales of experiments and simulations allows us to formulate a realistic microscopic picture of the crystal-liquid transition. According to the experimental data, the melting process gradually accelerates with the increasing density of deposited energy. The molecular dynamics simulations reveal that the transition mechanism progressively varies from heterogeneous, initiated inside the material at structurally disordered grain boundaries, to homogenous, proceeding catastrophically in the crystal volume on a picosecond timescale comparable to that of electron-phonon coupling. We demonstrate that the existing models of strongly non-equilibrium melting, developed for systems with relatively weak electron-phonon coupling, remain valid even for ultrafast heating rates achieved in femtosecond laser-excited Pd. Furthermore, we highlight the role of pre-existing and transiently generated crystal defects in the transition to the liquid state.

Globally-significant arsenic release by wildfires in a mining-impacted boreal landscape

Metal mining and smelting activities are one of the largest anthropogenic sources of arsenic pollution to the environment, with pervasive consequences to human and environmental health. Several decades of metal processing activities near Yellowknife, NT, Canada have resulted in widespread accumulation of arsenic in biomass, soils, and sediments, exceeding environmental and human health limits. The landscape surrounding Yellowknife is frequently disturbed by wildfire, most recently in 2023, when 2500 km2 burned. While wildfire-mediated release of stored arsenic around Yellowknife likely represents an incipient threat to human and ecosystem health, a quantification of the potential magnitude of arsenic remobilization from wildfires is absent. Here we combine publicly available soil and biomass arsenic concentrations and land cover datasets with the current best estimates of pyrogenic arsenic speciation and release in upland and wetland ecosystems to estimate the potential range of arsenic remobilization due to wildfires in the region surrounding Yellowknife from 1972 to 2023. Since 1972, wildfires have potentially led to the release of 141–562 Mg of arsenic, with 61–381 Mg emitted to the atmosphere and 39–109 Mg mobilized as water-soluble species. The large range in potential atmospheric emissions was due to the range in peat emission efficiency (5%–84%) that resulted in more arsenic being released from wetlands than the uplands. In 2023 alone, our estimated atmospheric release from just four wildfires was between 15%–59% of global annual arsenic wildfire emissions and likely represented between 2 and 9% of total global arsenic emissions from all natural sources. Given that climate change has and will continue to increase both annual area burned and soil burn severity, we emphasize that future increased wildfire activity closer to Yellowknife will place legacy soil arsenic stores at risk of an even larger catastrophic and unprecedented release, especially as wetlands become drier.

On Spontaneous Dispersion as a Cause of Microstratification of Metal Melts.

The phenomenon of spontaneous dispersion is considered as the cause of the microstratification of metal melts. In a microstratification melt, a violation of long-range order in the arrangement of atoms (LRO) is observed, which corresponds to a dispersed particle size of more than 2 nm. Microseparation occurs due to spontaneous dispersion upon contact of liquid and solid metal or the mixing of two liquid metals. The possibility of spontaneous dispersion was assessed using three different criteria: Volmer's cr iterion, Rehbinder's criterion and the diffusion rate criterion. The diffusion rate criterion was obtained on the basis of the theory of rate processes, which describes how diffusing atoms overcome the interphase boundary. It has been established that Al-Sn melts contain colloidal-scale particles (4 nm), and Al-Si and Al-Ge melts contain atomic-scale particles (0.1 nm). For a system with a continuous series of Cu-Ni solid solutions in dispersion (Cu10Ni90-Cu20Ni80), the particle size is 2 nm. The particle size of the ternary eutectic GaInSn in the dispersion (Ga50In50-Ga50Sn50) is 5.6 nm, and the size of immiscible Cu-Fe melts in the dispersion (Cu80Fe20-Cu60Fe40) is 4.8 nm. Long-range order violations (LRO) and the presence of microlayering with colloidal particles larger than 20 nm were observed in the GaInSn ternary eutectic, in the Al-Sn simple eutectic with the preferential interaction of similar atoms, and in Cu-Fe melts with a monotectic phase diagram.

Considering the bioavailability and bioaccessibility of metal(loid)s for risk assessment of soils affected by different non-ferrous metal activities in Southwest China

Toxic metal(loid)s released into the soil by non-ferrous metal mining and smelting activities pose a serious threat to residents and the surrounding ecosystem. Considering only total metal(loid) concentrations likely overestimates routine (eco)toxicological risk assessment of soil. We hypothesize that considering metal(loid) bioavailability/accessibility will improve the accuracy of risk assessment. To test this hypothesis, four mining areas in Southwest China, including mining and surrounding sites, were studied. Bioavailability was determined considering metal(loid)s leached by a simulated strong acid rain (SSAR) treatment. In the four areas, the mining site showed higher cumulative releases of metal(loid)s under SSAR treatment than the agricultural field located in the surrounding sites. Thus, the bioavailable metal(loid)s contents were continuously being released during SSAR treatment and likely increased the environmental risk. Ecological and health risk assessment of soil, calculated using total metal(loid)s content, was corrected considering bioavailable/accessible metal(loid)s, which was determined by the heavy metal(loid)s forms and in vitro simulated intestinal stages. Although the corrected indices indicated that the risk of metal(loid)s-contaminated soil was reduced, unfavorable ecological and health risks remained in the four areas. Our study provides new perspectives to better predict the risk of bioavailable/accessible metal(loid)s in non-ferrous metal contaminated and surrounding soils.

Moss as a passive biomonitoring tool for the atmospheric deposition and spatial distribution pattern of toxic metals in an industrial city.

Anthropogenic pollution impacts human and environmental health, climate change, and air quality. Karabük, an industrial area from the Black Sea Region in northern Türkiye, is vulnerable to environmental pollution, particularly soil and air. In this research on methodological aspects, we analyzed the concentrations of six potential toxic metals in the atmospheric deposition of the city using the passive method of moss biomonitoring. The ground-growing terrestrial moss, Hypnum cupressiforme Hedw., was collected during the dry season of August 2023 at 20 urban points. The concentrations of Cr, Cu, Cd, Ni, Pb, and Co were determined in mosses by the ICP-MS method. Descriptive statistical analysis was employed to evaluate the status and variance in the spatial distribution of the studied metals, and multivariate analysis, Pearson correlation, and cluster analysis were used to investigate the associations of elements and discuss the most probable sources of these elements in the study area. Cd and Co showed positive and significant inter-element correlations (r > 0.938), representing an anthropogenic association mostly present in the air particles emitted from several metal plants. The results showed substantial impacts from local industry, manufactured activity, and soil dust emissions. Steel and iron smelter plants and cement factories are the biggest emitters of trace metals in the Karabük area and the primary sources of Cr, Cd, Ni, and Co deposition.

An Examination of Bronze Vessel Technology in the Unified Silla Period: Case Study on the Bronzes Excavated from Gwanbuk-ri Site in Buyeo

Archaeological excavations in Buyeo had revealed Bronze vessels interred within a hole in the building at the Gwanbuk-ri site. These bronze vessels are dated to the Unified silla period (9-10th centuries). To identify the bronze vessels’ manufacturing technology, metallurgical analyses were carried out using Optical Microscopy, SEM-EDS and EPMA. The results allowed a reconstruction of the manufacturing process of bronze vessels in the Unified silla. It proved that bronze vessels were manufactured with Cu-Sn alloy with varying tin contents, which may be related to the application of uncontrolled procedures in making the bronze alloys. Also a casting process was used to shape the bronze vessels and the strength and hardness of the container were improved through a quenching process. Twins were observed in one of the samples, so it was assumed that hot working had been attempted. Non-metallic inclusions in bronze vessels have circular or polygonal shapes, and Cu and S were detected. The presence of Cu-S inclusions showed the probable use of copper sulphide ores for metal production and smelting. Se and Te in the inclusions of the bronze vessels show that the copper ore is different. From the results of metallurgical analyses of bronze vessels excavated from other regions of the same era, casting and quenching treatments were confirmed, and the sequential relationship of the technological system was revealed.

Silica-supported ionic liquid for efficient gaseous arsenic oxide removal through hydrogen bonding

The emission of highly-toxic gaseous As2O3 (As2O3 (g)) from nonferrous metal smelting poses environmental concerns. In this study, we prepared an adsorbent (SMIL-X) by loading an ionic liquid (IL) ([HOEtMI]NTf2) into MCM-41 through an impregnation–evaporation process and then applied it to adsorb As2O3 (g). SMIL-20% exhibited an As2O3 (g) adsorption capacity of 35.48 mg/g at 400 °C, which was 490% times higher than that of neat MCM-41. Characterization of SMIL-X indicated that the IL was mainly supported on MCM-41 through O–H…O bonds formed between the hydroxyl groups (–OH) and the silanol groups (Si–OH) and the O–H…F bonds formed between the C–F groups and the Si–OH groups. The hydrogen bonds significantly contributed to the adsorption of As2O3 (g), with –NH and –OH groups forming hydrogen bonds with As–O species (i.e., N–H…O and O–H…O). This showed superior performance to traditional adsorbents that rely on van der Waals forces and chemisorption. Moreover, after exposure to high concentrations of SO2, the adsorption capacities remained at 76% of their initial values, demonstrating some sulfur resistance. This study presents an excellent adsorbent for the purification of As2O3 (g) and shows promising application potential for treating flue gas emitted by nonferrous metal smelting processes.

Assessing the Impact of PM2.5-Bound Arsenic on Cardiovascular Risk among Workers in a Non-ferrous Metal Smelting Area: Insights from Chemical Speciation and Bioavailability.

Inhalation of fine particulate matter PM2.5-bound arsenic (PM2.5-As) may cause significant cardiovascular damage, due to its high concentration, long transmission range, and good absorption efficiency in organisms. However, both the contribution and the effect of the arsenic exposure pathway, with PM2.5 as the medium, on cardiovascular system damage in nonferrous smelting sites remain to be studied. In this work, a one-year site sample collection and analysis work showed that the annual concentration of PM2.5-As reached 0.74 μg/m3, which was 120 times the national standard. The predominant species in the PM2.5 samples were As (V) and As (III). A panel study among workers revealed that PM2.5-As exposure dominantly contributed to human absorption of As. After exposure of mice to PM2.5-As for 8 weeks, the accumulation of As in the high exposure group reached equilibrium, and its bioavailability was 24.5%. A series of animal experiments revealed that PM2.5-As exposure induced cardiac injury and dysfunction at the environmental relevant concentration and speciation. By integrating environmental and animal exposure assessments, more accurate health risk assessment models exposed to PM2.5-As were established for metal smelting areas. Therefore, our research provides an important scientific basis for relevant departments to formulate industry supervision, prevention and control policies.

Joule heating analyses in electrically conductive micro/nano-sized structures

Joule heating is occurred in electrically conductive materials. In cracked structures with high concentration of electric current at the crack tip vicinity the Joule heating can be extremely high and even a melting of metal can be observed. It is interesting to investigate thermal stresses caused by this local heating. In micro/nano-sized structures the overheating of structures can be very fast and structure can be damaged. However, in these small structures it is observed the size effect for both heat transport and also for the mechanical balance equation. The thermal transport cannot be described by the classical Fourier’s equation in materials with an internal structure. For mechanical problem due to the size effect the strain gradients have to be considered in the constitutive equations. Then, governing equations for both problems are given by partial differential equations with order of derivatives being higher than in classical case. The collocation mixed FEM is developed here for this multi-physical problem. The present computational method is applied to some crack problem to illustrate compressive stresses at the crack tip vicinity, which are leading to the crack closure.

A comparative study on the corrosion, wear, and tribocorrosion performances of Ti-6.5Al–2Zr–1Mo–1V (TA15) alloy fabricated by selective laser melting and laser metal deposition

Corrosion-erosion performances of Ti-6.5Al–2Zr–1Mo–1V (TA15) alloy fabricated by two laser additive manufacturing technologies, namely selective laser melting (SLM) and laser metal deposition (LMD) were investigated, and compared with those of traditional forged counterpart. Results show that SLM-ed TA15 possesses better corrosion, wear, and tribocorrosion resistances than LMD-ed and forged TA15. This is mainly attributed to the ultrafine-grain αʹ phase in the microstructure of SLM-ed sample, which improves the hardness and thereby enhances the wear and tribocorrosion resistance. Additionally, the complete αʹ phase formed in SLM-ed sample also avoids the galvanic corrosion that occurs at the α+β-type LMD-ed and forged samples.

TEMPUS-A microgravity electromagnetic levitation facility for parabolic flights.

During the ∼22s lasting free fall phase in an aircraft flying a parabola, the aboard installed electromagnetic levitation facility "TEMPUS" is used to investigate contactless and undisturbed of gravity induced convection thermophysical properties and microstructure formations of hot and highly reactive metal or semiconductor melts. The completely contactless handling and measurement of a liquid by the levitation technique keeps the melt free of contamination and enables the extension of the accessible sample temperature range far into the undercooled liquid state below the melting point. Additionally, the state of reduced weight during parabolic flights allows us to considerably decrease the strongly disturbing electromagnetic levitation forces acting in ground-based facilities on the suspended liquids. The present paper explains in detail the basic principle and the technical realization of the TEMPUS levitation facility and its attached measurement devices. Furthermore, it presents some typical experiments performed in TEMPUS, which also show the advantages resulting from the combination of reduced weight, electromagnetic levitation, and contactless measurement techniques. The control and data recording, as well as the planning, preparation, and operation of the TEMPUS experiments within the parabolic flight campaign, are another aspect outlined in the following.

Multiple pathway exposure risks and driving factors of heavy metals in soil-crop system in a Pb/Zn smelting city, China

Heavy metals (HMs) in soil near metal smelting areas have attracted great interest due to their crucial threat to agricultural product safety and human health. We investigated HMs in agricultural soils and crops (wheat and maize) in a Pb/Zn smelting city, central China; analysed the exposure risk of HMs through multiple pathways in a soil-crop system through Monte Carlo simulations; and identified the key driving factors using random forest (RF) model. The results showed that most soil HMs exceeded their background level. Cd had the highest exceeding rate compared with the screening values and the highest exceeding rate (40%, in wheat) compared with the food safety limit. Additionally, Cd had the highest bioaccumulation capacity in both maize and wheat. In identifying the key driving factors of soil HMs, RF had a satisfactory prediction performance for As, Cd, and Pb, with corresponding R2 values of 0.47, 0.51, and 0.60, respectively, with the dominant factors being distance to the Pb/Zn smelter, coal washery, and road area, respectively. However, Cr and Hg exhibited lower R2 values which may be due to their limited influence from the selected anthropogenic, traffic, and industrial variables. Probabilistic health risk assessments through Monte Carlo simulations revealed that the non-carcinogenic risk was around the risk limit (HI = 1), while the carcinogenic risk for both children and adults exceeded the risk limit (TCR = 1E-04), and adults had higher carcinogenic risk than children, which was due to a longer duration of exposure and higher ingestion rate of crop grains in adults. Cd had the highest carcinogenic risk and the highest probability of exceeding the limiting risk. Briefly, levels of Cd in both soil and crops should be controlled, especially for the source of smelting emissions. The results of this study could be treated as valuable references for policymakers to formulate control strategies for soil HM pollution in agricultural areas near Pb/Zn smelting activities.

Physical and Technological Features of Mechanoactivation of Powder Particles Formed during Hydro-Vacuum Dispersion of Metallic Melts

Physical and Technological Features of Mechanoactivation of Powder Particles Formed during Hydro-Vacuum Dispersion of Metallic Melts

Explainable Artificial Intelligence Approach for Diagnosing Faults in an Induction Furnace

For over a century, induction furnaces have been used in the core of foundries for metal melting and heating. They provide high melting/heating rates with optimal efficiency. The occurrence of faults not only imposes safety risks but also reduces productivity due to unscheduled shutdowns. The problem of diagnosing faults in induction furnaces has not yet been studied, and this work is the first to propose a data-driven framework for diagnosing faults in this application. This paper presents a deep neural network framework for diagnosing electrical faults by measuring real-time electrical parameters at the supply side. Experimental and sensory measurements are collected from multiple energy analyzer devices installed in the foundry. Next, a semi-supervised learning approach, known as the local outlier factor, has been used to discriminate normal and faulty samples from each other and label the data samples. Then, a deep neural network is trained with the collected labeled samples. The performance of the developed model is compared with several state-of-the-art techniques in terms of various performance metrics. The results demonstrate the superior performance of the selected deep neural network model over other classifiers, with an average F-measure of 0.9187. Due to the black box nature of the constructed neural network, the model predictions are interpreted by Shapley additive explanations and local interpretable model-agnostic explanations. The interpretability analysis reveals that classified faults are closely linked to variations in odd voltage/current harmonics of order 3, 11, 13, and 17, highlighting the critical impact of these parameters on the model’s prediction.