The paper presents some particularities of the manufacturing in the vacuum induction furnace and the argon atmosphere of three Ni - base Inconel - like superalloys. As a novelty, besides the typical alloying elements, the alloys contain rhenium between 1 and 3%. By means of optical and scanning electron microscopy/energy-dispersive X-ray spectrometry (SEM-EDS), the compositional and microstructural differences after casting were analyzed. The alloy that contains the smallest amount of Re, but also Mo, has a structure that reveals a lesser dendritic segregation, creating favorable premises for subsequent processing and also a high refractoriness.

The paper presents the results of research carried out on three samples of martensitic stainless steel used in the manufacture of hydropower turbine blades. The experiments were carried out under normal aeration conditions at ambient temperature (22 degrees C) in freshly prepared solutions of 1N potassium sulfate and 3% NaCl. The corrosion rates were calculated using the Tafel slope method. Analysis of the results regarding the corrosion behavior in Cl-free environments coupled with the microstructural information obtained by SEM highlights very good corrosion resistance properties (very good resistance class) as well as the appropriate passivation of the surface. This recommends the three steels for use in the construction of hydropower turbine blades. The negative influence of chlorine on the surface is highlighted by reducing the degree of passivation by half, which does not recommend the use of this material in a saline environment.

Microplastics (MPs) and nanoplastics (NPs) both represent significant concerns in environmental sciences. This paper aims to develop a convenient and efficient methodology for the detection and measurement of MPs and nanoparticles from surface seawater and to apply it to the water samples collected from the UNESCO site of Venice and its lagoon, more precisely in the Venice-Lido Port Inlet, Grand Canal under Rialto Bridge, and Saint Marc basin. In this study, MPs were analyzed through optical microscopy for their relative abundance and characterized based on their color, shape, and size classes, while the concentration and the mean of nanoparticles were estimated via the Nanoparticle Tracking Analysis technique. Bulk seawater sampling, combined with filtration through a cascade of stainless-steel sieves and subsequent digestion, facilitates the detection of MPs of relatively small sizes (size classes distribution: >1 mm, 1000–250 μm, 250–125 μm, 125–90 μm, and 90–32 μm), similar to the size of MPs ingested by marine invertebrates and fishes. A protocol for minimizing interference from non-plastic nanoparticles through evaporation, digestion, and filtration processes was proposed to enrich the sample for NPs. The findings contribute to the understanding of the extent and characteristics of MPs and nanoparticle pollution in the Venice Lagoon seawater, highlighting the potential environmental risks associated with these pollutants and the need for coordinated approaches to mitigate them. This article is based on scientific research carried out within the framework of the H2020 In-No-Plastic—Innovative approaches towards prevention, removal and reuse of marine plastic litter project (G.A. ID no. 101000612).

Estrogens, widely used for therapeutic or contraceptive purposes, act as endocrine disruptors in aquatic systems and have adverse effects on a wide range of living organisms. Wastewater insufficiently treated by conventional methods is the main way for estrogens to enter aquatic systems. Therefore, the purpose of this paper is to develop a novel photocatalytic system for the removal of the estrogenic mixture estradiol valerate/norgestrel from wastewater. The photocatalytic modules are operated in a plug flow reactor system under a UV-A radiation field, and the photocatalyst (TiO2, ZnO or TiO2/ZnO) is immobilized on an inert support of glass balls that are strung on stainless-steel wire and arranged in rows along the photocatalytic modules. The photocatalysts were synthesized by the sol–gel method and then deposited on the inert glass support by the hot method, after which it was calcined for two hours at a temperature of 500 °C. The experimental results showed that the efficiency of photocatalytic degradation largely depends on the dose of photocatalyst. The dose of photocatalyst can be adjusted by adding or removing photocatalytic modules, each of which have an approximately equal amount of photocatalyst. The best result was obtained for the TiO2/ZnO photocatalyst, the organic substrate being practically mineralized in 120 min, for which only two photocatalytic modules are needed.

The objective of the research is to establish the causes that led to the shutdown of a recirculation compressor following the failure of several springs in the intake and exhaust valve system. The Inconel X750 superalloy is known as a material with excellent corrosion and mechanical performance in a wide range of temperatures and working environments, being used for highly stressed components in steam turbines, gas turbines, petrochemical equipment or nuclear energy. The choice of Inconel X750 superalloy for the execution of valve springs of compressors is correct, it has mechanical characteristics in a relatively wide band, depending on the applied heat treatment.Structural and chemical analyzes were carried out on damaged springs in order to determine the material quality and also the matrix and precipitates chemical composition by SEM -EDAX. HV50 hardness tests were made and phenomena that determined the springs breaking were evaluated by SEM fractographic analyses.

Anthropogenic microplastics (MPs) and nanoplastics (NPs) are ubiquitous pollutants found in aquatic, food, soil and air environments. Recently, drinking water for human consumption has been considered a significant pathway for ingestion of such plastic pollutants. Most of the analytical methods developed for detection and identification of MPs have been established for particles with sizes > 10 μm, but new analytical approaches are required to identify NPs below 1 μm. This review aims to evaluate the most recent information on the release of MPs and NPs in water sources intended for human consumption, specifically tap water and commercial bottled water. The potential effects on human health of dermal exposure, inhalation, and ingestion of these particles were examined. Emerging technologies used to remove MPs and/or NPs from drinking water sources and their advantages and limitations were also assessed. The main findings showed that the MPs with sizes > 10 μm were completely removed from drinking water treatment plants (DWTPs). The smallest NP identified using pyrolysis–gas chromatography–mass spectrometry (Pyr-GC/MS) had a diameter of 58 nm. Contamination with MPs/NPs can occur during the distribution of tap water to consumers, as well as when opening and closing screw caps of bottled water or when using recycled plastic or glass bottles for drinking water. In conclusion, this comprehensive study emphasizes the importance of a unified approach to detect MPs and NPs in drinking water, as well as raising the awareness of regulators, policymakers and the public about the impact of these pollutants, which pose a human health risk.

Solid activators based on waste glass for the manufacture of one-part alkali-activated fly ash/red mud materials were synthesized, characterized, and tested in this work. The synthesis was carried out via alkaline fusion with sodium hydroxide at different reaction temperatures and at different sodium hydroxide/waste glass mass ratios. The results showed that the reaction temperature decisively influences the properties of the obtained solid activators. Thus, the best results regarding the water solubility of solid activators were obtained for the synthesis temperature of 600 °C, regardless of the sodium hydroxide/waste glass mass ratio. Also, the use of these assortments of solid activators led to obtaining the best compressive strength of one-part alkali-activated fly ash/red mud materials. The best results were obtained for the solid activator synthesized at a temperature of 600 °C and a sodium hydroxide/glass waste mass ratio of two.

The aim of this study was to design a dual-layer wound dressing as a new fibrous biomaterial based on the valorization of animal-derived proteins. The first layer was fabricated by the deposition of poly(ethylene oxide) (PEO) loaded with keratin hydrolysate (KH) via a mono-electrospinning process onto a poly(lactic acid) (PLA) film, which was used as a support. The second layer consisted of encapsulating a bovine collagen hydrolysate (CH) into poly(vinyl pyrrolidone) (PVP) through a coaxial electrospinning process, which was added onto the previous layer. This assemblage was characterized by electronic microscopy for morphology and the controlled release of KH. In vitro biocompatibility was evaluated on the L929 (NCTC) murine fibroblasts using quantitative MTT assay and qualitative cell morphological examination after Giemsa staining. Additionally, in vivo biocompatibility methods were used to assess the impact of the biomaterial on white Swiss mice, including the evaluation of hematological, biochemical, and immunological profiles, as well as its impact on oxidative stress. The results revealed a nanofibrous structure for each layer, and the assembled product demonstrated antioxidant activity, controlled release of KH, a high degree of in vitro biocompatibility, negligible hematological and biochemical changes, and minimal impact of certain specific oxidative stress parameters compared to the use of patches with textile support.

Automotive industry is constantly interested in building cars made of light and high strength parts in order to reduce the emission levels, the fuel consumption and minimize the effects of a car crash. Some parts may be made of lighter materials, but the steel ones must compensate the strength needed for the car body. Research is made for finding new materials showing high strength combined with high ductility. Among them, transformation -induced -plasticity steels are of great interest, efforts being made to improve their characteristics. A new composition of such a steel is presented, its features being compared with those of three other steels of the same class and category. Optical microscopy at different magnifications is performed, together with Vickers hardness test. Structural particularities are found for each tested steel, justified by their own chemical compositions. The new steel reveals important characteristics: besides the mainly bainitic structure, it has both larger ferritic areas and amounts of retained austenite, making him proper for further study.

The objective of the study was to prepare, characterize, and test a chitosanmagnetite (CS-Fe3O4) nanocomposite as an efficient adsorbent used in the removal of iron ions and decrease in turbidity from a real water sample. The CS-Fe3O4 was characterized using FTIR spectrometry, OM, SEM, and XRD analyses, and the physical and chemical properties of the water samples were determined using standardized methods. The CS-Fe3O4 presented a good adsorption capacity for Fe ions and a decreased turbidity after 24 hours. One advantage of this research is the high efficiency of the nanocomposite and the easy possibility of recuperating, regenerating, and reusing the material in future research.

Usually alloys from the titanium-niobium-zirconium-tantalum (TNZT) do not have intrinsic antibacterial properties and to induce such properties introducing alloying elements (silver, in this case) such property can be induced. This research is aimed at studying the influence of tantalum concentration variation on the microstructure of as cast alloys from the TNZT system with 2% silver addition. The alloys were obtained by vacuum-arc remelting (VAR) and characterized by light and scanning electron microscopy, X-Ray diffraction and Vickers hardness tests. The studies are performed on as cast ingots, the intended use for the alloy being dentistry applications. The alloy density was also determined using the water displacement method, the highest tantalum concentration (20%) resulting on a density of 6.87 +/- 0.01g/cm(3). The results showed that the addition of tantalum increases beta-phase content, generates a change in a-phase morphology and increases hardness starting from 15%wt.

Magnetite nanoparticles have attracted interest of researchers from different science fields such as medicine, biology, physics, or chemistry due to their multifunctional properties including biocompatibility, superparamagnetism and low toxicity. Several methods have been developed to synthesize magnetic nanoparticles with controlled size, shape, and magnetic properties. Among them, coprecipitation is the most widely used because of several advantages such as high-yield production of nanoparticles, its simplicity, low-cost and its eco-friendly reaction conditions, but it also has low reproducibility. To achieve the magnetic nanoparticles with the desired properties, the investigation and control of reaction parameters are essential. In this article, the mechanism of coprecipitation reaction for magnetite nanoparticle synthesis and recent studies in reaction parameters controlling the particle properties will be reviewed. In addition, the most used methods for structural and magnetic characterization of magnetite and magnetite functionalized nanoparticles are presented and exemplified.

Water pollution stands as a pressing global environmental concern, elevating the significance of innovative, dependable, and sustainable solutions. This study represents an extensive review of the use of photocatalytic zinc oxide nanoparticles (ZnO NPs) for the removal of emerging pollutants from water and wastewater. The study examines ZnO NPs’ different preparation methods, including physical, chemical, and green synthesis, and emphasizes on advantages, disadvantages, preparation factors, and investigation methods for the structural and morphological properties. ZnO NPs demonstrate remarkable properties as photocatalysts; however, their small dimensions pose an issue, leading to potential post-use environmental losses. A strategy to overcome this challenge is scaling up ZnO NP matrices for enhanced stability and efficiency. The paper introduces novel ZnO NP composites, by incorporating supports like carbon and clay that serve as photocatalysts in the removal of emerging pollutants from water and wastewater. In essence, this research underscores the urgency of finding innovative, efficient, and eco-friendly solutions for the removal of emerging pollutants from wastewater and highlights the high removal efficiencies obtained when using ZnO NPs obtained from green synthesis as a photocatalyst. Future research should be developed on the cost–benefit analysis regarding the preparation methods, treatment processes, and value-added product regeneration efficiency. Graphical Abstract

Abstract In the context of the industrial evolution towards Industry 5.0 concept, there is an increase in the industrial processes automation and digitization which can bring several benefits but also challenges for human health protection. Thus, it is important that governments and industrial companies take a series of measures to detect health problems that may be related to harmful substances exposure during industrial processes. The paper deals with a subject of industrial ecosociology represented by the interactions of three systems: natural-ecological (particulate matters pollution of the atmosphere), technological (polluting particulate matters in processing of metallic materials), social (health status under negative impact of polluting particulate matters). The negative influence of particulate matters on human health is investigated with regard to the particle characteristics, namely size, dp [m], concentration, cp [g/m3], granulometric fractions, fg [%], elemental chemical composition and granulometric structure. The following aspects are approached: the importance of industrial ecosociology concerns for sustainable development of human existence; the need of engineers to know the industrial ecosociology targets; the ranking of metallurgy sectors (sintering plant, blast furnace, LD converter, electrical arc furnace – EAF, rolling mills) according to the impact of pollutants particulates that may affect human health induced diseases is assessed. JEL Classifications F64, I15, J81, O14, Q57

The present research aimed to identify the causes that led to the deterioration of a pipeline comprised in the benzene hydrofining equipment of a refinery. The pipeline ascending branch was perforated, therefore the installation was stopped in order to remove it and replace it. To find the causes of the premature degradation the following investigations were performed: macroscopic examination of the pipe elbow, chemical composition, microstructure and hardness, analysis of the porosity zone from the welded joint, analysis of corrosion products deposit samples taken from inside the pipe by X-ray fluorescence and X-ray diffractometry, assessment of the different corrosion processes affecting the pipeline.

The paper presents the impact of exceeding the railway rails lifespan which usually causes a railway structural failure, thus an accident. The research highlights the rails's high degradation, especially on the running area, consisting in 60-70% weight loss by advanced wear of the rail, followed by fatigue fracture caused by alternating cyclic stresses that initiates the crack and also by tensile stresses resulting in the crack growth. The chemical composition, structural and mechanical properties were analyzed in order to establish the causes that led to the railway rails rupture.

The research focused on TiO2 nanostructures environmental applications due to the special characteristics that displayed degradation of the organic compounds into environmentally friendly products through exposure to UV light. The protocol behind obtaining the nanostructures involved the use of a Ti material exposed to alkaline treatment and advanced oxidation using NaOH solution and acetone. These studied nanostructures were analyzed extensively by using methods such as scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) for characterizing the elements, compounds and morphological properties of the material. These differences in morphology is attributed to different NaOH solution concentrations. The Ti sheets were immersed into NaOH and acetone mixed solutions for 72 hours. The best results were recorded by using 30% NaOH solution. After obtaining the 3D structures, which improve specific surface and contact area with the environment, the samples were tested under UV light in order to degrade methylene blue in order to determine their photocatalytic performance.

Ferrous waste by-products from the metallurgical industry have a high potential for valorization in the context of the circular economy, and can be converted to value-added products used in environmental remediation. This research reviews the latest data available in the literature with a focus on: (i) sources from which these types of iron-based wastes originate; (ii) the types of ferrous compounds that result from different industries; (iii) the different methods (with respect to the circular economy) used to convert them into products applied in water and wastewater decontamination; (iv) the harmful effects ferrous wastes can have on the environment and human health; and (v) the future perspectives for these types of waste.

This paper presents a comparison between four TRIP steels, which belong to two groups with different chemical compositions. The first group is that of steels with a relatively low contents of Mn (1.5–2%), high Al (1–2%) and about 0.2% C, and the second includes steels with lower percentages of C (0.1%) and Al (max. 0.6%), but with high percentages of Mn (over 5%). The steels were heat treated by incomplete austenitization, isothermally cooled in salt baths at 400 °C, followed by air cooling. The heat-treated samples were subjected to the impact bending test. A comparative study was performed from the point of view of the intensity of the TRIP effect, the development of the retained austenite-to-martensite transformation under shock (studied by SEM), X-ray analysis and hardness measurements. It was found that appropriate and similar behaviors in terms of mechanical shock were shown by two steels belonging to different groups, with similar amounts of the retained austenite being turned into martensite fractions. The steel with the highest Mn percentage was distinguished by having the highest hardness (362 HV) and the highest retained austenite (obtained after heat treatment) and martensite fractions (caused by the TRIP effect) (10.63% and 2.17%, respectively).

An efficient, economical and emerging method used for the valorization of biomass waste is hydrothermal carbonization (HTC). The aim of this study was to develop eco-materials from grape stems waste, using an environmentally friendly method. The structural and morphological properties of the eco-materials were investigated by means of ATR-FTIR and SEA/I-EDS. Based on the results, these ecomaterials derived via HTC from grape stems waste can be further used in environmental applications, such as water depollution.