Metal Products Research Articles

Incidence of type 2 diabetes and metabolic syndrome by Occupation – 10-Year follow-up of the Gutenberg Health Study

BackgroundIn view of demographic change, rising retirement age, and a growing shortage of skilled workers, it is increasingly important to prevent widespread diseases such as type 2 diabetes or its risk factor metabolic syndrome. Since the workplace is an important setting for preventive measures and little is known about incident cases in the working population, the aim of this study was to identify vulnerable occupational groups for whom these interventions are particularly appropriate. Therefore, we investigated the 10-year incidence of type 2 diabetes and metabolic syndrome across occupational groups in Germany.MethodsEmployees of the population-based Gutenberg-Health-Study (GHS) were examined at baseline (2007–2012) and 10 years later. We calculated age- and sex-standardised incidence rates and standardised incidence ratios (SIR) with a 95% confidence interval (CI) for occupations, job complexity levels, and supervisory and managerial positions. 5954 persons at risk for type 2 diabetes and 5103 at risk for metabolic syndrome were observed.ResultsBetween baseline and follow-up, 388 cases of type 2 diabetes and 1104 cases of metabolic syndrome occurred, and standardised incidences were 6.9% and 22.6%, respectively. The highest incidence of type 2 diabetes was observed in the occupational group “food production and processing” (20.7%) with a threefold increased incidence (SIR = 3.0, 95% CI 1.8–4.7) compared to the total working population of the GHS. Employees in “metal production, processing and construction” had the highest incidence of metabolic syndrome and a two times higher SIR (48.5%; SIR = 2.1, 95% CI 1.4–2.9). There was also a high incidence of both type 2 diabetes and metabolic syndrome in “cleaners” (16.5% and 34.8%) and “drivers and mobile plant operators” (14.8% and 41.2%). An increased incidence of type 2 diabetes and metabolic syndrome was observed with decreasing job complexity levels.ConclusionsThis study shows wide differences in the incidence of type 2 diabetes and metabolic syndrome between occupational groups and highlights the vulnerability of certain occupations. As the workplace is an important platform for interventions, the findings of this study could guide the development of more nuanced and effective workplace health initiatives to promote a healthier workforce for the future.

Iterative sublattice amorphization facilitates exceptional processability in inorganic semiconductors.

Cold-forming processing is a crucial means for the cost-effective production of metal and alloy products. However, this process often results in catastrophic fracture when applied to most inorganic semiconductors owing to their inherent brittleness. Here we report the unique room-temperature plastic deformation mechanism involving sublattice amorphization coupled with Ag-ion diffusion in inorganic semiconductors Ag2Te1-xSx (0.3 ≤ x ≤ 0.6), and an ultrahigh extensibility of up to 10,150%. Once subject to external stress, the crystalline Te/S sublattice undergoes a uniform transformation into an amorphous state, whereas the Ag cations continuously bond with Te/S anions, endowing bulk Ag2Te1-xSx with exceptional plastic deformability. Remarkably, even slight polishing can induce sublattice amorphization in the surface layers. Furthermore, this sublattice amorphization can be reversed to crystals through simple annealing, enlightening the iterative sublattice amorphization strategy, with which metal-like wire drawing, curving, forging and ultrahigh ductility have been obtained in bulk Ag2Te1-xSx at room temperature. These results highlight sublattice amorphization as a critical plastic deformation mechanism in silver chalcogenide inorganic semiconductors, which will facilitate their applications in flexible electronics and drive further exploration of more plastic inorganic semiconductors.

Simulating the Failure Mechanism of High-Slope Angles Under Rainfall-Mining Coupling Using MatDEM

The safety production of gold, silver, copper, and other important metals is seriously threatened in the process of mining from open-pit to underground due to various factors such as infiltration caused by rainfall and unloading during mining. Furthermore, the current situation of open-pit mining in an increasing number of mines presents a high and steep terrain, which poses significant security risks. Accordingly, it is of great practical significance to investigate the failure mechanism of high-slope angles to ensure the long-term safe mining of mines, considering factors such as rainfall infiltration and excavation unloading. In this study, the slope failure of high-slope angles (45°, 55°, and 65°) under rainfall-mining coupling was analyzed using the discrete element MatDEM numerical simulation software. Herein, the stress distribution, failure characteristics, and energy conversion of the model were simulated under different slope angles to analyze the failure mechanism at each stage. The simulation results show that the damage scale is smallest at 55° and largest at 65°. This indicates that setting the slope angle to 55° can reduce the risk of slope instability. Moreover, the reduction of elastic potential energy during the mine room mining stage is similar to that of mechanical energy. During the pillar mining stage, stress is concentrated in each goaf, resulting in a greater reduction in mechanical energy compared to elastic potential energy. Finally, after the completion of the continuous pillar mining stage, stress becomes concentrated in the failure area, and the effect of the slope angle on mechanical energy reduction becomes evident after the complete collapse of the model.

MАRKАZIY QIZILQUM QОRА SLАNES MА’DАNLАRINI KUYDIRISH JАRАYОNINING ОPTIMАL PАRАMETRLАRINI TАDQIQ QILISH

Particular attention is paid to the improvement of existing technologies for increasing the volume of ore processing, utilization of man-made waste, difficult-to-process ores and off-balance low-grade waste, involvement in the processing of man-made minerals that replace natural minerals in the production of precious metals, development of technologies for the extraction of rare metals and new technologies for the extraction of rare and precious metals from industrial waste, development of new technologies for the extraction of precious metals.

Analysis of Service Quality and Brand Image on Customer Satisfaction and Loyalty: Case Study of Precious Metal Products

Analysis of Service Quality and Brand Image on Customer Satisfaction and Loyalty: Case Study of Precious Metal Products

Non-Linear Hyperelastic Model Analysis and Numerical Validation of 3D Printed PLA+ Material Incorporating Various Infill Densities

Additive manufacturing (AM) or 3D printing technology creates a tangible object by adding successive layers of materials. Nowadays, 3D printing is used for developing both metal and non-metal products. In the advancement of 3D printing technology, material specimen design, modification, and testing become very simple, especially for non-metal materials, such as hyperelastic, thermoplastic, or rubber-like materials. However, proper material modeling and validation are required for the analysis of these types of materials. In this study, 3D printed poly lactic acid (PLA+) material behavior is analyzed numerically for validation in the counterpart of experimental analysis to evaluate their behavior in both cases. The specimen was designed in SolidWorks by following ASTM D638 dimension standards with proper infill densities and raster angle or infill orientation angle. These infill layer densities and angles of orientation play an important role in the mechanical behavior of the specimen. This paper aims to present a numerical validation of five infill densities (20%, 40%, 60%, 80%, and 100%) for a ±45-degree infill angle orientation by incorporating a nonlinear hyperelastic model. Results indicate that infill densities affect the mechanical behavior of PLA+ material. The result also suggested that neo-Hookean and Mooney–Rivlin are the best-fitted hyperelastic material models for these five separate linear infill densities. However, neo-Hookean is easier to analyze, as it has only one parameter and a new equation is developed in this study for determining the parameter for different infill densities.

Life cycle comparison of industrial-scale lithium-ion battery recycling and mining supply chains

Recycling lithium-ion batteries (LIBs) can supplement critical materials and improve the environmental sustainability of LIB supply chains. In this work, environmental impacts (greenhouse gas emissions, water consumption, energy consumption) of industrial-scale production of battery-grade cathode materials from end-of-life LIBs are compared to those of conventional mining supply chains. Converting mixed-stream LIBs into battery-grade materials reduces environmental impacts by at least 58%. Recycling batteries to mixed metal products instead of discrete salts further reduces environmental impacts. Electricity consumption is identified as the principal contributor to all LIB recycling environmental impacts, and different electricity sources can change greenhouse gas emissions up to five times. Supply chain steps that precede refinement (material extraction and transport) contribute marginally to the environmental impacts of circular LIB supply chains (<4%), but are more significant in conventional supply chains (30%). This analysis provides insights for advancing sustainable LIB supply chains, and informs optimization of industrial-scale environmental impacts for emerging battery recycling efforts.

Overview of historical occupational exposure to trichloroethylene in China.

Trichloroethylene (TCE) is a carcinogen that has been causally linked to kidney cancer and possibly other cancer sites including the liver and lymphatic system. Its use in China has increased since the early 1990s due to the growing metal and electronic industries. We aimed to summarize the major sources of occupational exposure to TCE over time in China. Occupational TCE exposure assessments were extracted from both the Chinese and English scientific literature, as well as from industrial hygiene surveys performed in Guangdong, Tianjin, and Hong Kong. Weighted mean concentrations were summarized by occupation and industry. We extracted over 12,412 measurements from 55 industries and 35 occupations across China since 1976, of which at least 201 were from case reports. More than half of the measurements were derived from 4 industries, including "manufacture of footwear" (29%), "manufacture of electronic components and boards" (17%), "manufacture of games and toys" (14%), and "manufacture of fabricated metal products, except machinery and equipment" (13%). Several occupations, including "electronic-equipment assemblers," "metal-, rubber-, and plastic-products assemblers," "metal finishing-, plating-, and coating-machine operators," "precision-instrument makers and repairers," "printing-machine operators," and "ore and metal furnace operators" were identified as having high risks of TCE exposure, with either pooled weighted mean task-based or full-shift concentrations over 150mg/m3 over the years. TCE exposure levels varied across different occupations and changed over time. In 1990 and earlier, 1991 to 2000, the exposure levels were at their highest with pooled weighted mean task-based concentrations of 202.8 and 242.9mg/m3, respectively. Subsequently, the level decreased to 118.7mg/m3 from 2001 to 2010 before increasing again to 216.0mg/m3 from 2011 onwards. This overall trend was also observed for "electronic-equipment assemblers" and "metal finishing-, plating-, and coating-machine operators." However, for "precision-instrument makers and repairers," the exposure levels consistently declined over the years. Over the past few decades, degreasing-related occupations, such as "electronic-equipment assemblers" and "metal finishing-, plating-, and coating-machine operators" have been consistently identified as being at high risk of significant TCE exposure and continued to warrant attention. Identifying high-risk industries and occupations can inform the development of targeted interventions and regulations to mitigate TCE exposure. Furthermore, enhancing the quality and coverage of exposure measurement data in occupational settings will advance epidemiological investigations in occupational health.

Stellar population and metal production in AGN discs

ABSTRACT As gravitational wave detections increase the number of observed compact binaries (consisting of neutron stars or blacks), we begin to probe the different conditions producing these binaries. Most studies of compact remnant formation focus either on stellar collapse from the evolution of field binary stars in gas-free environments or on the formation of stars in clusters where dynamical interactions capture the compact objects, forming binaries. But a third scenario exists. In this paper, we study the fate of massive stars formed, accrete gas, and evolve in the dense discs surrounding supermassive black holes. We calculate the explosions produced and compact objects formed by the collapse of these massive stars. Nucleosynthetic yields may provide an ideal, directly observable, diagnostic of the formation and fate of these stars in active galactic nuclei. We present a first study of the explosive yields from these stars, comparing these yields with the observed nucleosynthetic signatures in the discs around supermassive stars with quasars. We show that, even though these stars tend to form black holes, their rapid rotation leads to discs that can eject a considerable amount of iron during the collapse of the star. The nucleosynthetic yields from these stars can produce constraints on the number of systems formed in this manner, but further work is needed to exploit variations from the initial models presented in this paper.

Figuring Out Gas and Galaxies In Enzo (FOGGIE). VIII. Complex and Stochastic Metallicity Gradients at z > 2

Abstract Gas-phase metallicity gradients are a crucial element in understanding the chemical evolution of galaxies. We use the FOGGIE simulations to study the metallicity gradients (∇Z) of six Milky Way–like galaxies throughout their evolution. FOGGIE galaxies generally exhibit steep negative gradients for most of their history, with only a few short-lived instances reaching positive slopes that appear to arise mainly from interactions with other galaxies. FOGGIE concurs with other simulation results but disagrees with the robust observational finding that flat and positive gradients are common at z &gt; 1. By tracking the metallicity gradient at a rapid cadence of simulation outputs (∼5–10 Myr), we find that theoretical gradients are highly stochastic: the FOGGIE galaxies spend ∼30%–50% of their time far away from a smoothed trajectory inferred from analytic models or other, less high-cadence simulations. This rapid variation makes instantaneous gradients from observations more difficult to interpret in terms of physical processes. Because of these geometric and stochastic complications, we explore nonparametric methods of quantifying the evolving metallicity distribution at z &gt; 1. We investigate how efficiently nonparametric measures of the 2D metallicity distribution respond to metal production and mixing. Our results suggest that new methods of quantifying and interpreting gas-phase metallicity will be needed to relate trends in upcoming high-z James Webb Space Telescope observations with the underlying physics of gas accretion, expulsion, and recycling in early galaxies.

Achieving High Solid–Liquid Ratio through Competitive Coordination towards Efficient Recovery of Metals from Spent Batteries

AbstractThe recycling of critical metals from spent lithium‐ion batteries represents a significant step towards meeting the enhancing resource requirements in the new energy industry. Nevertheless, achieving effective leaching of metals from the stable metal‐oxygen (MO6) structure of spent ternary cathodes and separation of metal products simultaneously still remained a huge challenge towards industrial applications. Herein, a competitive coordination strategy was proposed to design a novel deep eutectic solvent (DESs), which improved both leaching and selective metal recycling capacity even at high solid–liquid ratio (1 : 10). The results demonstrated that the number of hydrogen bonds in designed ternary DESs was 16.5 % higher compared to those in the binary DESs, resulting in efficient reaction kinetics to break the metals‐oxygen bond. More importantly, the competing‐ligand (p‐toluenesulfonic acid) could preferentially enter into the first nanostructure sheath and reduce the proportion of solvated oxalic acid (OxA) from 28.36 % to 17.76 % within the nanostructure, which enable OxA molecules to enhance the coordination interaction with metal for precipitating NiC2O4 ⋅ 2H2O product (~95.7 % purity) from spent cathodes. This work achieved impressive profitability ($16.05 per kg feedstock) and effectively reduction of GHG emissions during the recycling process, making it applicable to critical sustainability initiatives.

Exploiting outcomes of life cycle costing to conduct coherent screening social life cycle assessments of emerging systems: a case study of microalgae biorefineries

Abstract Purpose Microalgae are considered a promising source of bioenergy and high value-added products that could help face the rising demand for energy and raw materials. However, microalgae systems entail consumption of materials and energy, with potential environmental, economic, and social costs. While environmental and economic impacts have been analyzed in the literature, the social dimension has been barely explored. In this article, social life cycle assessment (S-LCA) is applied to identify the main contributors to social risks. Methodology In this paper, an approach is proposed and applied to exploit outcomes of a Life Cycle Costing (LCC) study as the input data to model and evaluate the potential social impacts of microalgae biorefinery schemes. Such approach helps ensure the consistency between the economic and social assessments, while facilitating data gathering in a context of data scarcity typical of an emerging technology. Priority levels for stakeholder categories and impact subcategories have been assigned based on the literature. Workers and local communities were identified as the stakeholders with the highest priority, related to impact subcategories such as health and safety issues and fair salary for the former and local employment for the latter. An inventory model was built, using PSILCA database v2.0 Starter and openLCA software, together with cost estimates from an LCC using real data from experiments at lab and pilot scale. Results According to the results, the main contribution to social risks of the biogas production is expected to be linked to the anaerobic digestion. Some contributors, both from the cultivation and the anaerobic digestion, are basic chemicals production and market public sewage activities, together with civil engineering and construction, and metal products and machinery production. The geographical distribution of risks depends on the stakeholder category and impact subcategory. Since many activities of the value chain are assumed to happen in Spain, a non-negligible part of social risks take place there. However, other countries with minor contributions to total working time are found to have the highest social risk for subcategories and indicators such as fatal accidents. Finally, three scenarios have been compared, considering production in a Chinese, French, or Spanish context, which lead to significant differences. Conclusions This study aims to highlight the importance of assessing the different dimensions of sustainability in a coherent manner. Furthermore, it provides useful information and hints on main contributors to potential social impacts in the microalgae-based sector based on available information and generic S-LCA databases, and their dependence on geographical locations of the life cycle activities. Despite limitations, conducting such social assessments with available tools is key to better understand the need for widening the scope of sustainability studies.

Complex Study of Settlements Dating from the Paleolithic to Medieval Period in the Ural Mountains on the Border of Europe and Asia

Soil, geochemical, microbiological, and archeological studies were conducted at eight settlements dating from the Paleolithic to Late Medieval and Modern Ages near the southern Trans-Urals Mountains, Russia. The forest-steppe landscapes, rivers, and abundant mineral resources have attracted people to the region since ancient times. Cultural layers (CLs) are marked by finds of ceramics fragments, animal bones, stone, and metal tools. The properties of CLs include close-to-neutral pH, being well structured, the absence of salinity, enrichment with exchangeable calcium, and anthropogenic phosphorus (0.2–0.4%). The majority of CLs start at a depth of 3–25 cm, extend to 40–60 cm, and contain 6–10% organic carbon (Corg) in the 0–20 cm layer, reflecting carbon input from modern-day processes. At the Ishkulovo site (0.6–0.8 ka BP), Corg decreases to 1.3% because the CL is below 80 cm, and in the absence of fresh organic material input, carbon has been mineralized. The proximity of sites to deposits of copper, chromium, zinc, and manganese in the Ural Mountains creates natural high-content anomalies in the region, as indicated by their abundance in soils and parent rocks. In the past, these elements were also released into CLs from metal products, ceramic fragments, and raw materials used in their manufacture. The sites are quite far (18–60 km) from the Magnitogorsk Metallurgical plant, but industrial stockpiles of S (technogenic coefficient—Ct 30–87%), and, less often, Cr, Mn, and Sr (Ct 30–40%) accumulated in surface layers. These three factors have led to the concentration of pollutants of the first (arsenic, chromium, lead, and zinc) and second (cobalt, copper, and nickel) hazard classes at CLs, often in quantities 2–5 times higher than values for parent materials and geosphere average content (“Clarke” value), and, and less often, more than the allowable content for human health. This may have influenced their health and behavioral functions. Due to the above properties, chernozems have a high buffering capacity and a strong bond with heavy metals. Therefore, no inhibition of microbes was observed. The microbial biomass of the 0–10 cm layer is high, 520–680 µg C/g, and microbes cause the emission of 1.0 C-CO2 µg/g of soil per hour. During the ancient settlements’ development, a favorable paleoclimate was noted based on the data cited. This contributed to the spread of productive paleolandscapes, ensuring the development of domestic cattle breeding and agriculture.

A Perspective Study on the Challenges Faced by the Small-Scale Industries during COVID-19

Small and Medium Enterprises with various ventures, such as equipment and machinery manufacturing, metal and electrical products, cement, food and drinks, construction and construction supplies, rubber and plastic goods, and automation technologies, are seeing considerable expansion in the Indian market. The Covid-19 pandemic has impacted all economic sectors, but SMEs in India have been particularly hard hit. The current effect of coronavirus on SME's in India is investigated in this study. So that after smoke clears, SME's discover that they must grow and change over time to stay profitable. Safeguard processes, hygiene and disinfection techniques, a revised procurement strategy, the integration of affiliate marketers, standardising their product range, a much more receptive assessment of supply chain management, and an assessment of catastrophe or disaster response plans are some of the answers to this problem. This study author is trying to analyse the challenges faced by small scale industries during lockdown period and the government initiatives in this regard.

Analysis of the evolution in the number of manufacturing companies in Portugal between 2009 and 2021 to understand growth and decline trends

This project analyzes the evolution of the manufacturing sector in Portugal from 2009 to 2021, focusing on the variations in the number of active companies across various subcategories, such as food, textiles, and metal product industries. The goal of this analysis is to understand the dynamics of growth and contraction within each sector, providing insights for companies to adjust their market and operational strategies. Key objectives include analyzing the overall evolution in the number of companies, identifying subcategories with notable changes, and providing a comprehensive analysis of observed trends and patterns. The study is based on data from PORDATA 2024, and the research employs temporal trend analysis, linear and quadratic regression, and the Pareto representation to identify patterns of growth and decline. By comparing annual data, the project uncovers periods of growth and decline, allowing for a deeper understanding of the sector’s dynamics. The findings also highlight variations in periods of economic crises and during the Covid-19 pandemic, and recommendations for action are presented to support businesses resilience and continuity. These results are valuable for companies within the manufacturing sectors analyzed and policy makers, guiding strategic decisions to navigate the complexities of the market dynamics and to ensuring long-term organizational sustainable success.

Development of the structure of a cyberphysical control system for the process of tailored induction heating of a steel billet

The article is devoted to the development of the structure of a cyberphysical control system for the process of zone induction heating, widely used in modern industrial production during the heat treatment of metal products for various purposes. An analysis of the range of products manufactured using induction heat treatment and the advantages of using induction heating systems has shown a wide range of applications of this method of heat treatment in modern production and great opportunities for automation and optimization of processes associated with induction heating of products. This fact indicates the relevance of the development of various kinds of intelligent control systems in relation to the processes of industrial induction heating of metal blanks and semi-finished products. The article describes the induction method of zone heat treatment of metals, its advantages over flame heat treatment methods and the range of products manufactured using it. A description of the billet-inductor system is presented, for which the structure of a cyberphysical control system for the process of zone induction heating has been developed. The technological requirement for the final temperature distribution on the surface of the workpiece and the factors influencing the deviation of the temperature distribution from that required in the process of zone induction heating are considered. A list of possible disturbing influences is given, requirements for the technological process are formulated, control principles are described and, based on this, the structure of the zone induction heating process control system, which belongs to the class of cyberphysical process control systems, is developed.

Suppression of mycotoxins production and efficient chelation of heavy metals using natural melanin originated from Aspergillus flavus and Aspergillus carbonarius

BackgroundThis study employed melanin synthesized by Aspergillus flavus and Aspergillus carbonarius to inhibit the production of mycotoxins and bioremediation of heavy metals (HMs).MethodsFirst, twenty fungal isolates were obtained from soil samples, and were evaluated to produce melanin. The melanin of the most potent producers has undergone several confirmatory experiments, including, Dihydroxyphenylalanine (DOPA)-inhibitor-kojic acid pathway detection, High-performance liquid chromatography (HPLC), Fourier-transform infrared (FTIR) and Nuclear magnetic resonance (NMR). Additionally, the melanin production culture conditions were optimized. The antioxidant activity of melanin was detected with 1,1-Diphenyl-2-picrylhydrazyl (DPPH). HPLC was used to measure the mycotoxins produced in culture media supplemented with melanin. Molecular docking study investigated molecular interactions between melanin and mycotoxins through in silico approaches. FTIR and Energy-dispersive X-ray spectroscopy (EDX) were utilized to determine the percentage of melanin-chelated HMs, and an atomic absorption spectrophotometer (AAS) was used to detect HMs removal efficiency.ResultsThe melanin-enriched medium (0.3% and 0.4%) exhibited complete inhibition of aflatoxin B1 (AF-B1) by A. flavus and ochratoxin A (OTA) by A. carbonarius, respectively. Furthermore, melanin showed effective HM removal efficiency, increasing with melanin concentration. The removal efficiency of Cd+2 and Cr+6 by 1 mg/mL melanin was 49% and 63%, respectively. When the concentration of melanin was increased to 15 mg/mL, the removal efficiency of Cd+2 and Cr+2 increased to 60% and 77%, respectively.ConclusionThe study exhibited a natural approach for melanin production, using melanin as a heavy metal-chelating agent and capability to inhibit the production of aflatoxin B1 and ochratoxin A. Further, the study provides significant evidence regarding the bioremediation pipeline, for melanin production through biotechnological processes by filamentous fungi.

Early Strength Enhancement Mechanism of CaO-Modified Electrolytic Manganese Residue-Based Supersulfate Cement.

Electrolytic manganese residue (EMR) is a solid waste generated during the production of electrolytic manganese metal through wet metallurgy, accumulating in large quantities and causing significant environment pollution. Due to its high sulfate content, EMR can be utilized to prepare supersulfate cement when combined with Ground Granulated Blast furnace Slag (GGBS). In this process, GGBS serves as the primary raw material, EMR acts as the sulfate activator, and CaO powder, along with trace amounts of cement, functions as the alkali activator. This results in the preparation of CaO-modified electrolytic manganese residue-based supersulfate cement (Abbreviated as "SSC"), facilitating the harmless and resourceful utilization of EMR. This study aims to determine the optimal dosage of CaO as the alkali activator for GGBS in SSC. A comprehensive analysis was conducted on four groups, including a control group. The mass ratio of EMR, GGBS, and cement in SSC was fixed as 35:60:5, and the optimum mixing ratio of lime powder as an external admixture was investigated through mechanical tests and microscopic experiments. The hydration products and mechanism of the cementitious materials were analyzed using X-ray diffraction (XRD), pH measurements, thermogravimetric and differential thermogravimetric analysis (TG-DTG), mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM). The results indicated that, under the combined influence of trace cement and raw lime powder, EMR effectively activated GGBS. The primary hydration products of the SSC are AFt and hydrated calcium silicate (C-S-H), which contributed to the mechanical strength of the SSC. At a hydration age of 3 days, the optimal CaO blending ratio was found to be 8% by mass of dried EMR. With this ratio, the compressive strength of SSC reached 18.2 MPa, the pore size of hardened slurry was refined, the structure became dense, and hydration products increased. It could be concluded that CaO enhances the early strength of SSC when used as an alkali activator.

Silver coin chemical composition two-parameter control system: measuring instruments selection for mass fraction of components

The article considers general requirements for quality control of precious metal products. It presents an algorithm for developing a quality control system for silver coins and features of its application in monitoring the chemical composition of coins with a silver content of 79.7% to 92.8% (the balance is copper). An algorithm has been developed for making decisions based on the two-parameter control results, including mathematical models for calculating the indicators of control reliability (the probability of types I and II errors). The calculation of the errors in measuring mass fractions of silver and copper (standard deviation) was performed with the required reliability (the probability of type I errors is 0.10). The article describes the dependence of the probability of type I errors on the error (standard deviation) of mass fraction of alloy components in silver coins measurement result, which can be used to justify the requirements for the indicators of measurement accuracy. Based on the criteria “Analyzed elements”, “Measurement range”, “Error”, X-ray fl uorescence spectrometers were proposed for use in the control system. The described algorithm for developing a controlsystem and its implementation in monitoring the chemical composition of silver coins will be useful to employees involved in precious metals and jewelry in specialized institutes and organizations in the manufacturing industry, banks, jewelry stores, pawnshops.

Corrosion Study of Clutch Air Spring Gas Circuit under Salt Spray Test

This study provides an in-depth analysis of the corrosion resistance of metal products in marine environments, and specifically examines the effectiveness of Type 12S-1 anticorrosive coating in protecting metals in marine environments. The corrosion-resistant behavior of different metal materials under marine conditions is discussed in depth, and a theoretical basis for subsequent simulation experiments is established through electrochemical corrosion theory. This paper focuses on the corrosion performance of clutch air spring airways under different metal materials and conditions of coated or uncoated Type 12S-1 anticorrosive coating, and salt spray tests are used to evaluate and compare the corrosion protection effectiveness of various treatments. The results proved that the 17-4pH material still showed excellent corrosion resistance without coating, and the application of Type 12S-1 anticorrosive coating could enhance the corrosion resistance of the metal to a certain extent. This study not only provides a solid theoretical and empirical foundation for metal anti-corrosion technology in the marine environment, but also provides an important guidance for the optimization of anti-corrosion strategies for ship materials, and provides practical references and directions for the development of related industries.