Production of WE43 magnesium alloy by powder metallurgy and the effect of glucose on wear resistance in biocorrosive wear.

In this study, WE43 magnesium alloy was produced by the powder metallurgy method. Microstructural analyses of the produced samples were carried out using the scanning electron microscopy method. X-ray fluorescence, energy dispersive x-ray (EDS) analysis, and hardness tests were also implemented to investigate the physical and chemical properties of the alloys. The volumetric hardness was measured to be approximately 53 HV. The microstructural analysis and EDS results indicated the presence of Mg24Y5 and Mg41Nd5 phases in the alloys. Reciprocating-type experiments were carried out in dry and corrosive environments to evaluate the wear resistance. Hanks's solution containing 2% g/l glucose was used as the corrosive environment. Gluconic acid resulting from the oxidation of glucose in the Hanks's solution formed a new thin layer on the alloy surface, which was observed in the worn surface images. The formation of the thin film on the alloy surface resulted in an increase in wear resistance by 37%. The results unraveled the potential of the WE43 alloys as implant materials in areas in contact with glucose.

[Microorganisms used for bioleaching of metals from typical solid wastes and their leaching mechanism: a review].

Typical solid wastes contain many metal resources, which are worthy of recycling. The bioleaching of typical solid waste is affected by multiple factors. Green and efficient recovery of metals based on the characterization of leaching microorganisms and the elucidation of leaching mechanisms may contribute to the implementation of China's "dual carbon" strategic goals. This paper reviews various types of microorganisms used for leaching metals from typical solid wastes, analyzes the action mechanism of metallurgical microorganisms, and prospects the application of metallurgical microorganisms to facilitate the application of metallurgical microorganisms in typical solid wastes.

Design, metallurgy, mechanical properties, and shaping ability of 3 heat-treated reciprocating systems: a multimethod investigation.

OBJECTIVE: This study aimed to compare 3 reciprocating systems regarding design, metallurgy, mechanical properties, and shaping ability. MATERIALS AND METHODS: New Reciproc Blue R25, WaveOne Gold Primary, and REX 25 instruments (n=41 per group) were analyzed regarding design, metallurgy, and mechanical performance, while shaping ability (untouched canal walls, volume of removed dentin, and hard tissue debris) was tested in 36 anatomically matched root canals of mandibular molars. Results were compared using one-way ANOVA post hoc Tukey and Kruskal-Wallis tests with a significant level set at 5%. RESULTS: All instruments showed symmetrical cross sections with asymmetrical blades, no radial lands, no major defects, and an almost equiatomic nickel and titanium ratio. The highest R-phase start temperatures were observed with WaveOne Gold (46.1°C) and REX (44.8°C), while Reciproc Blue had the lowest R-phase start (34.5°C) and finish (20°C) temperatures. WaveOne Gold had the lowest time to fracture (169 s) and the highest maximum load (301.6 gf) (P <0.05). The maximum torque of Reciproc Blue (2.2 N.cm) and WaveOne Gold (2.1 N.cm) were similar (P >0.05), but lower than REX (2.6 N.cm) (P <0.05). No statistical differences were observed among instruments in the angle of rotation (P >0.05) and in the shaping ability in both mesial and distal canals (P >0.05). CONCLUSION: Although the overall design, temperature transition phases and mechanical behavior parameters were different among tested instruments, they were similar in terms of shaping ability. CLINICAL RELEVANCE: All tested heat-treated NiTi reciprocating systems showed similar shaping ability, without clinically significant errors.

Environmental protection subsidies, green technology innovation and environmental performance: Evidence from China's heavy-polluting listed firms.

The heavy-polluting industry is inexorably to responsible for the deterioration of the environment. Improving environmental performance is an unavoidable decision for heavy-polluting firms to ensure sustainable development under the policy framework of the carbon peak target. This study provides theoretical and empirical evidence for the effect of environmental protection subsidies on environmental performance. This study constructs basic and mediating effect models to measure how environmental protection subsidies affect environmental performance using panel data of China's heavy-polluting listed firms from 2008 to 2019. This is an important outcome of industrial green transformation in environmental governance and provides a scientific basis for government departments to formulate environmental policies. The results of the empirical analysis show that environmental protection subsidies can improve the environmental performance of heavy-polluting listed firms. After receiving environmental protection subsidies, firms engaged in clean and green production through green technology innovation, thereby reducing external environmental pollution and improving their environmental performance. The mediating role of green technology innovation in the relationship between environmental protection subsidies and environmental performance is significant only in state-owned firms and firms in Eastern China. The research results may further guide the direction of green development of heavy-polluting industries, and thus promote harmonious development between the environment and the economy.

Direct imitation or indirect reference?-research on peer effects of enterprises' green innovation.

This paper takes the China's A-share listed companies in the heavy pollution industry from 2010 to 2021 as the research sample and constructs a corresponding model to explore the existence, heterogeneity, and economic consequences of peer effect of green innovation. The results show that the enterprises' green innovation not only has strategic behaviors of direct imitation, but also receives the environmental information disclosed by peer enterprises to correct their own decision-making; that is, there are two types of peer effects: imitation and reference. At the same time, the enterprises tend to imitate and learn from large-scale and high-quality enterprises with high governance level while making decisions on green innovation. External situational characteristics can moderate the peer effects of green innovation. The strengthening of intellectual property protection and the improvement of market competition will promote mutual learning and reference among enterprises, and the improvement of the institutional environment will inhibit the interaction of enterprises. Further analysis shows that the peer effect of imitation amplifies the promoting effect of green innovation on business performance, while the peer effect of reference does not show obvious spillover characteristics. The above analysis is helpful to reveal the more real decision-making motivation and potential driving mechanism for enterprises to take green innovation actions and provides new ideas and experience for green innovation to serve the development of entity enterprises.

Systematic control technologies for gaseous pollutants from non-ferrous metallurgy.

Air pollutant emissions represent a critical challenge in the green development of the non-ferrous metallurgy industry. This work studied the emission characteristics, formation mechanisms, phase transformation and separation of typical air pollutants, such as heavy metal particles, mercury, sulfur oxides and fluoride, during non-ferrous smelting. A series of purification technologies, including optimization of the furnace throat and high-temperature discharge, were developed to collaboratively control and recover fine particles from the flue gas of heavy metal smelting processes, including copper, lead and zinc. Significant improvements have been realized in wet scrubbing technology for removing mercury, fluoride and SO2 from flue gas. Gas-liquid sulfidation technology by applying H2S was invented to recycle the acid scrubbing wastewater more efficiently and in an eco-friendly manner. Based on digital technology, a source reduction method was designed for sulfur and fluoride control during the whole aluminum electrolysis process. New desulfurization technologies were developed for catalytic reduction of the sulfur content in petroleum coke at low temperature and catalytic reduction of SO2 to elemental sulfur. This work has established the technology for coupling multi-pollutant control and resource recovery from the flue gas from non-ferrous metallurgy, which provides the scientific theoretical basis and application technology for the treatment of air pollutants in the non-ferrous metallurgy industry.

The provenance of the raw material and the manufacturing technology of copper artefacts from the Copper Age hoard from Magyaregres, Hungary.

In 2016, a Stollhof-type copper hoard was found during an excavation in Magyaregres, Hungary. It was placed in a cooking pot, and deposited upside down within the boundaries of an Early Copper Age settlement. Similar hoards dating to the end of the 5th millennium BCE are well-known from Central Europe, however, this hoard represents the only one so far with thoroughly documented finding circumstances. The hoard contained 681 pieces of copper, 264 pieces of stone and a single Spondylus bead, along with 19 pieces of small tubular spiral copper coils, three spiral copper bracelets, and two large, spectacle spiral copper pendants. Until now, information on the provenance of raw materials and how such copper artefacts were manufactured has not been available. The artefacts were studied under optical microscopes to reveal the manufacturing process. Trace elemental composition (HR-ICP-MS) and lead isotope ratios (MC-ICP-MS) were measured to explore the provenance of raw materials. The ornaments were rolled or folded and coiled from thin sheets of copper using fahlore copper probably originating from the Northwestern Carpathians. A complex archaeological approach was employed to reveal the provenance, distribution and the social roles the ornaments could have played in the life of a Copper Age community. Evidence for local metallurgy was lacking in contemporaneous Transdanubian sites, therefore it is likely that the items of the hoard were manufactured closer to the raw material source, prior to being transported to Transdanubia as finished products. The method of deposition implies that such items were associated with special social contexts, represented exceptional values, and the context of deposition was also highly prescribed. The Magyaregres hoard serves as the first firm piece of evidence for the existence of a typologically independent Central European metallurgical circle which exploited the raw material sources located within its distribution.

The Predominant Sources of Heavy Metals in Different Types of Fugitive Dust Determined by Principal Component Analysis (PCA) and Positive Matrix Factorization (PMF) Modeling in Southeast Hubei: A Typical Mining and Metallurgy Area in Central China.

To develop accurate air pollution control policies, it is necessary to determine the sources of different types of fugitive dust in mining and metallurgy areas. A method integrating principal component analysis and a positive matrix factorization model was used to identify the potential sources of heavy metals (HMs) in five different types of fugitive dust. The results showed accumulation of Mn, Fe, and Cu can be caused by natural geological processes, which contributed 38.55% of HMs. The Ni and Co can be released from multiple transport pathways and accumulated through local deposition, which contributed 29.27%. Mining-related activities contributed 20.11% of the HMs and showed a relatively high accumulation of As, Sn, Zn, and Cr, while traffic-related emissions contributed the rest of the HMs and were responsible for the enrichment in Pb and Cd. The co-applied source-identification models improved the precision of the identification of sources, which revealed that the local geological background and mining-related activities were mainly responsible for the accumulation of HMs in the area. The findings can help the government develop targeted control strategies for HM dispersion efficiency.

Microstructure, Mechanical, In Vitro Biodegradation, and Antimicrobial Behavior of a Mg-Zn-Ca-Sr/ZrO2 Composite Prepared Using Powder Metallurgy.

Biodegradable materials, especially Mg alloys, have an exceptional advantage over nonbiodegradable materials in orthopedic applications, such as avoiding second surgery for removal/replacement, stress shielding, but not enough mechanical strength, and so forth. By further improving the Mg alloy to get all the remaining required properties, it can be used for better biodegradable implants, which depend adequately on material optimization, processing, and so forth. A Mg-Zn-Ca-Sr/ZrO2 composite has been prepared using powder metallurgy by adding 0, 1, 2, and 3 wt % of ZrO2, which also contains Zn, Ca, and Sr as nutrient elements. Microstructure characterization, as well as mechanical and in vitro biodegradation, have been investigated by hardness, compression, and immersion tests. The highest compressive strength, contraction, and hardness of about 185.6 MPa, 9.5%, and 65.2 HRB are observed in the 2% ZrO2-containing composite, respectively, whereas a minimum biodegradation rate of 2.76 mm/year is observed on the same. The antibiotic sensitivity observations against Staphylococcus aureus suggest that the alloy C3 has superior biological activity against the pathogen which ranks this alloy on top in merit. Overall, Mg-Zn-Ca-Sr/ZrO2 exhibits impressive potential for use as a biodegradable and antibiotic material for orthopedic applications.

How to Efficiently Reduce the Carbon Intensity of the Heavy Industry in China? Using Quantile Regression Approach.

This decoupling between carbon dioxide emissions and the heavy industry is one of the main topics of government managers. This paper uses the quantile regression approach to investigate the carbon intensity of China's heavy industry, based on 2005-2019 panel data. The main findings are as follows: (1) incentive-based environmental regulations have the greater impact on the carbon intensity in Jiangsu, Shandong, Zhejiang, Henan, Liaoning, and Shaanxi, because these provinces invest more in environmental governance and levy higher resource taxes; (2) the impact of mandatory environmental regulations on carbon intensity in Beijing, Tianjin, and Guangdong provinces is smaller, since these three provinces have the fewest enacted environmental laws and rely mainly on market incentives; (3) conversely, foreign direct investment has contributed most to carbon intensity reduction in Tianjin, Beijing, and Guangdong provinces, because these three have attracted more technologically advanced foreign-funded enterprises; (4) technological progress contributes more to the carbon intensity in the low quantile provinces, because these provinces have more patented technologies; (5) the carbon intensity of Shaanxi, Shanxi, and Inner Mongolia provinces is most affected by energy consumption structures because of their over-reliance on highly polluting coal.

[Analysis on the rationality of input and output of occupational health funds in an iron and steel enterprise].

Objective: To analyzes the various occupational health investment and occupational health output of a steel enterprise, and propose a reasonable occupational health investment plan for this enterprise. Methods: In march 2016, various occupational health input and output data of various branches of an iron and steel company in 2015 were collected, and the efficiency of occupational health inputs and outputs of each branch was evaluated using data envelopment analysis (DEA) , and the branches with non-optimal efficiency were adjusted to propose a reasonable occupational health investment plan. Results: Among the branch plants investigated by this steel company, the occupational health input-output efficiency values of ironmaking north plant, power plant, hot rolling plant and stainless steel plant were 1, while the occupational health input-output efficiency of gas making plant, cold rolling plant, metallurgical furnace charge plant, coking plant, ironmaking south plant and long product plant were not the best, and the cold rolling plant has the lowest efficiency value of 0.759. For the cold rolling plant, only the parameters of acid rolling plant satisfy α=1 and s(-)=0, s(+)=0, while the remaining four workshops do not meet. After adjusting the inputs of each part according to the parameters, the occupational health output of the remaining four workshops can reach 1.7044, 2.0238, 1.3152 and 1.2136 times of the current workshop, respectively. Adjustment plans for other branch factories with unreasonable investment structures are also presented in the corresponding tables. Conclusion: The occupational health investment structure of the ironmaking south plant and other branches in this steel enterprise is unreasonable, and the adjustment using data envelopment analysis can maximize the benefits of its occupational health output.

Fuel exploitation and environmental degradation at the Iron Age copper industry of the Timna Valley, southern Israel.

Economic and industrial progress frequently comes at the expense of environmental sustainability. For the early Iron Age (~ eleventh to ninth centuries BCE) smelters of the ancient copper industry of the Timna Valley, southern Israel, where today the hyper-arid Aravah Desert provides sparse vegetation, woody fuel for metallurgical furnaces constituted the greatest limiting factor for continued operations. This study presents the first investigation into the fuel sources relied upon by this industry during its most intensive period, as reflected by hundreds of charcoal samples collected from two well-stratified and chronologically anchored accumulations of industrial waste. The two sites demonstrate similar results: a heavy reliance on the local vegetation, particularly Retama raetam (white broom) and the ecologically significant Acacia spp. (acacia thorn trees), two high-calorific and high-burning taxa best suited for such purposes. It was also observed that over the course of the industry, the search for fuel expanded, as evidenced by the later appearance of taxa unsuited for the prevailing regional conditions, hinting at the detrimental toll the industry took on the local ecosystem. Altogether, it is suggested that the lucrative copper industry ended due to limits in the availability of fuel, caused by anthropogenic hastening of desertification and environmental degradation.

Efficiency evaluation of green innovation of China's heavy pollution industries based on SBM-Lasso-Tobit model.

Green innovation has become the goal for promoting the transformation and upgrading heavy pollution industries in the context of high-quality development, and the key factor for the success of green innovation is increasing the green innovation efficiency of heavy pollution industries. To understand the current situation of China's industrial innovation and get out of the dilemma, we use non-expected Slacks-based model (SBM) to measure green innovation efficiency in Chinese industry, Lasso regression to screen the influencing factors of heavy pollution industries, tobit regression to study the influence degree and direction of different influencing factors on green innovation efficiency of heavy pollution industry. The results show that: (1) The green innovation efficiency of the 16 heavily polluting industries studied in this paper is generally low; (2) Coordination, green and openness all have a positive impact on the green innovation efficiency of the industry. (3) A certain degree of government scientific research support is conducive to improving the efficiency of industrial green innovation and exceeding the limit will have a restraining effect on enterprise innovation. According to the results, we put forward the corresponding policy implications.

Waste slag benefits for correction of soil acidity.

The global trend is to find new materials with improved environment friendly. The sustainable development of 2030 AGENDA and Waste Management Legislation sustain the disposal of a large quantity of slag at landfill sites by causing environmental consequences which has drawn attention to the need for its more effective recycling. Heavy industries have been operating in the Galati area for over 30 years and an ecological education is necessary for an efficient management of waste slag. The agricultural land resources are an issue world-wide and through this investigative study we showed that the mixture of blast furnace slag and waste slag dumped in landfill can help remediation of the soil acidity and increasing the crop yield. The chemical, structural and morphological properties of three investigated different slag samples are evaluated for recycling in agriculture. Results indicated that the obtained mixture of the slag waste dumped in landfill and of granulated metallurgical slag shows its usage in saving the affected lands. Therefore, by elemental analysis determined by X-ray fluorescence analytical equipment, the optimum weight ratio for the composition of soil-slag mixture were achieved. The obtained mixture presents a balance between soil pH = 5.2 corresponding to a medium acid soil and slag pH = 12.5 which corresponds as strongly basic character which is beneficial in amelioration process of acidic soils for the improving of soil characteristics.

Health risk assessment of particulate matter 2.5 in an academic metallurgy workshop.

Exposure to indoor PM2.5 is associated with allergies, eye and skin irritation, lung cancer, and cardiopulmonary diseases. To control indoor PM2.5 and protect the health of occupants, exposure and health studies are necessary. In this study, exposure to PM2.5 released in an academic metallurgy workshop was assessed and a health risk assessment was conducted for male and female students and technicians. Polycarbonate membrane filters and an active pump operating at a flow rate of 2.5 L/min were used to collect PM2.5 from Monday to Friday for 3 months (August-October 2020) from 08:00-16:00. PM2.5 mass concentrations were obtained gravimetrically, and the Multiple-Path Particle Dosimetry model was used to predict the deposition, retention, and clearance of PM2.5 in the respiratory tract system. The risk of developing carcinogenic and non-carcinogenic effects among students and technicians was determined. The average PM2.5 mass concentration for August was 32.6 µg/m3 32.8 µg/m3 for September, and 32.2 µg/m3 for October. The head region accounted for the highest deposition fraction (49.02%), followed by the pulmonary (35.75%) and tracheobronchial regions (15.26%). Approximately 0.55 mg of PM2.5 was still retained in the alveolar region 7 days after exposure. The HQ for male and female students was <1 while that of male and female technicians was >1, suggesting that technicians are at risk of developing non-carcinogenic health effects compared with students. The results showed a risk of developing carcinogenic health effects among male and female technicians (>1 × 10-5 ); however, there was no excess cancer risk for students (<1 × 10-6 ). This study highlights the importance of exposure and health studies in academic micro-environments such as metallurgy workshops which are often less researched, and exposure is underestimated. The results also indicated the need to implement control measures to protect the health of the occupants and ensure that the workshop rules are adhered to.

Environmental Information Disclosure, Digital Transformation, and Total Factor Productivity: Evidence from Chinese Heavy Polluting Listed Companies.

Environmental information disclosure, as a new environmental regulatory model, is important for achieving collaborative environmental pollution management and sustainable socioeconomic development. Based on the data of listed firms in China's A-share heavy pollution industry from 2009 to 2019, this paper empirically tested the impact of environmental information disclosure on the total factor productivity of enterprises and the contribution of digital transformation to this impact. An increase in the level of environmental information disclosure had a significant positive effect on the total factor productivity of enterprises. However, with the increase in digital transformation among enterprises, the effect of environmental information disclosure on total factor productivity improvement is gradually being replaced. The heterogeneity test results showed that the positive effect of environmental information disclosure on total factor productivity changed depending on property rights, firm size, and geographical location. The effect of environmental information disclosure was stronger for non-state firms, large firms, and firms located in the east-central region. Further mechanism tests showed that the effect was induced through innovation incentives and facilitated financing. The above results provide a valuable reference for a comprehensive understanding of the effect of environmental information disclosure on productivity and adjustment by the digital transformation of enterprises.

Study on public acceptance of decommissioning of a uranium mining and metallurgy facility in Hunan Province.

The decommissioning of uranium mining and metallurgy facilities involves sensitive issues of the local government and the public, which is related to the vital interests of the surrounding residents. Improper disposal may lead to negative emotions among the public and affect the process of uranium mining and metallurgy facilities decommissioning projects. In order to explore the acceptance of uranium mining and metallurgy decommissioning projects by nearby residents and its influencing factors, a hypothesis model of influencing factors of public acceptance was constructed through literature survey. Taking the public around a uranium mining and metallurgy in Hunan Province as an example, a questionnaire survey was carried out. Using the AMOS21.0 tool, the fitting test of the structural equation model was carried out on 506 valid sample data and the hypothetical model, and the key factors affecting the public acceptance of the uranium mining and metallurgy decommissioning project were analyzed. The findings show that public perceived risk (-0.28), familiarity (0.26) and trust (0.175) are key factors influencing acceptance. The research results provide a methodological basis for improving the public acceptance of uranium mining and metallurgy decommissioning projects.

Promoted mechanical properties and functionalities via Ta-tailored Ti-Au-Cr shape memory alloys towards biomedical applications.

In view of the urgent demands of shape memory alloys (SMAs) for biomedical applications due to the world population aging issue, the mechanical properties and functionalities of the biocompatible Ti-Au-Cr-based SMAs, which are tailored by Ta additions, have been developed in this study. The quaternary SMAs were successfully manufactured by physical metallurgy techniques and their mechanical properties and functionalities were examined. In the continuous tensile tests, it was found that the correlation between the yielding strength and phase stability followed a typical trend of mechanical behavior of SMAs, showing the lowest yielding strength at the metastable ß-parent phase. Functional mappings between the alloy strength and elongation revealed that compared to the Ta-free specimen, the ductility was promoted 50% while the strength remained intact through the 4 at.% introduction of Ta. Slight shape recovery was observed in the cyclic loading-unloading tensile tests during the unloading process and the highest shape recovery was found in the Ti-4 at.% Au-5 at.% Cr-4 at.% Ta specimen. This indicates that the 4 at.% Ta tailored Ti-Au-Cr SMAs could be a promising material for biomedical applications.

Mapping the Global Anthropogenic Chromium Cycle: Implications for Resource Efficiency and Potential Supply Risk.

Chromium (Cr) is a critical metal due to its non-substitutable application in the metallurgy industry and highly uneven distribution of global reserve. However, there is a lack of in-depth analysis of global Cr flow patterns and its trade networks among individual cycles, which leaves the potential barriers and opportunities unexplored for improving chromium resource efficiency. Here, we employ a trade-linked multilevel material flow analysis (MFA) to map the global anthropogenic Cr cycle for year 2019. Social network analysis is also used to identify the key countries involved in the global Cr trade network. The results highlight that the global Cr cycle depends substantially on international trade in different forms, of which stainless steel is the leading application. Although South Africa, Kazakhstan, and Turkey are the major Cr primary resource suppliers, China and India play substantial roles in manufacturing Cr-containing products. Regional disparities exist in the scrap contents of individual country cycles, varying from 7% (uncertainty ranges from 4 to 11%) in China to 88% (uncertainty ranges from 87 to 89%) in India. Additionally, several countries are essential in the global Cr redistribution and in the connectivity of the Cr trade network, which may lead to their strong import dependence and even supply disruption.

Exploring the Link Between the Serum/Blood Levels of Heavy Metals (Pb, As, Cd, and Cu) and 2 Novel Biomarkers of Cardiovascular Stress (Growth Differentiation Factor 15 and Soluble Suppression of Tumorigenicity 2) in Copper Smelter Workers.

OBJECTIVE: Studying the association between the occupational exposure to Pb, As, Cd, and Cu with the serum levels of 2 novel biomarkers of cardiovascular stress; growth differentiation factor 15 and soluble suppression of tumorigenicity 2, in some Egyptian Cu smelter workers. METHODS: Forty-one exposed workers and 41 administrative controls were clinically evaluated. Serum/blood levels of heavy metals and biomarkers were measured for both groups. RESULTS: The smelter workers showed significantly elevated levels of heavy metals and biomarkers compared with controls. The elevated serum levels of both biomarkers were significantly and positively correlated with each other, the levels of heavy metals, and the duration of employment of the exposed workers. CONCLUSIONS: There was a significant association between the levels of heavy metals and both biomarkers among the smelter workers. Further prospective studies should be performed.