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Hydrogen fuel holds promise for clean energy solutions, particularly in onboard applications such as fuel cell vehicles. However, the development of efficient hydrogen storage systems remains a critical challenge. This study addresses this challenge by exploring the potential of high-strength novel materials, including glass, to maximize onboard hydrogen storage capacity. A mathematical approach was employed to evaluate the feasibility and efficacy of various high-strength materials for hydrogen storage. This study focused on capillary arrays as a promising storage medium and utilized mathematical modeling techniques to estimate the storage capacity enhancement achievable with different materials. The analysis revealed significant variations in storage capacity enhancements in different high-strength novel materials, with glass having promising results. Glass-based materials demonstrated the potential to meet or exceed US Department of Energy (DOE) targets for both gravimetric and volumetric hydrogen storage capacities in capillary arrays. By leveraging a mathematical approach, this study identified high-strength novel materials, including glass and polymers, capable of substantially improving onboard hydrogen storage capacity: 29 wt.% with 40 g/L for quartz glass and 25 wt.% with 38 g/L for Kevlar compared to 5.2 wt.% with 26.3 g/L from a conventional type IV tank. These findings underscore the importance of material selection in optimizing hydrogen storage systems and provide valuable insights for the design and development of next-generation hydrogen storage technologies for onboard applications. [ABSTRACT FROM AUTHOR]

The service behavior of ductile metallic materials, when they have previously undergone technological plastic deformation, depends on the deformation conditions. These are represented, among others, by the deformation rate, the process temperature, the applied pressures, and the introduced stresses, as well as other process variables. The investigation of the mechanical properties obtained after plastic deformation is an important means that contains two characteristics: on the one hand, to determine to what extent the parameters of the technological manufacturing process influence the main characteristics of the final component; and, on the other hand, on the basis of these characteristics, to analyze whether the component subjected to plastic deformation will be able to function reliably and safely. In the present work, an experimental study was made of the residual stresses developed and hardnesses obtained both in the immediate vicinity of a highly plastically deformed area and in an area previously obtained by rolling, without additional plastic deformation. For the determination of the residual stresses, the tensiometric rosette drilling method was used. By determining the same quantities in a non-plastically deformed area, significant changes in the values of the two quantities in the plastically deformed area were found. An increase in the maximum principal normal stresses by approx. 60 MPa and an increase in the Rockwel hardness by approx. 10 HRC was found. A sample was taken from the area under a plastic deformed circular shape, and was analyzed microscopically. [ABSTRACT FROM AUTHOR]

This study is part of an international project titled "Energy Recovery from Municipal Solid Waste by Thermal Conversion Technologies in Cross-border Regions." Household waste samples for the experiments were collected from a landfill in Maramureș County, Romania. While previous research has outlined optimal incineration conditions for energy recovery, this paper focuses on the environmental impact of incineration, particularly gaseous emissions. Although incineration is an efficient method for waste disposal, it significantly impacts the environment through the release of gaseous emissions, slag, and ash. Effective management of these emissions is crucial to mitigate environmental and health risks, necessitating a detailed understanding of emission characteristics based on waste composition and combustion conditions. This paper presents a quantitative analysis of key pollutants in the gaseous emissions, including nitrogen oxides (NOx), sulfur dioxide (SO2), particulate matter (PM10), and volatile organic compounds (VOCs), specific to the sampled waste. The analysis was conducted using advanced gas analysis equipment during controlled incineration experiments. The results revealed high concentrations of NO2 and PM10, exceeding the threshold values set by the European Directive 2008/50/EC on air quality standards. To address the pollution from the incineration plant, the study recommends implementing a purification system focused on reducing suspended dust and neutralizing nitrogen oxides. These findings highlight the necessity for stringent emission control measures to minimize the environmental and health impacts associated with waste incineration. [ABSTRACT FROM AUTHOR]

The objective of this work was to analyze the in vitro and in vivo tests of a novel Mg-based biodegradable alloy—Mg-0.5%Ca—with various amounts of Zn (0.5, 1, 1.5, 2.0, and 3.0 wt.%). In terms of in vitro biocompatibility, MTT and Calcein-AM cell viability assays, performed on the MG-63 cell line through the extract method, revealed that all five alloy extracts are non-cytotoxic at an extraction ratio of 0.025 g alloy per mL of cell culture medium. In the in vivo histological analysis, Mg-0.5Ca-1.5Zn demonstrated exceptional potential for stimulating bone remodeling and showed excellent biocompatibility. It was observed that Mg-0.5Ca-0.5Zn, Mg-0.5Ca-1.5Zn, and Mg-0.5Ca-3Zn displayed good biocompatibility. Furthermore, the histological examination highlighted the differentiation of periosteal cells into chondrocytes and subsequent bone tissue replacement through endochondral ossification. This process highlighted the importance of the initial implant's integrity and the role of the periosteum. In summary, Mg-0.5Ca-1.5Zn stands out as a promising candidate for bone regeneration and osseointegration, supported by both in vitro and in vivo findings. [ABSTRACT FROM AUTHOR]

There are some important advantages presented by metal specimens coated with WIP-C1 (Ni/CrC)-type materials. However, given the coating methods and the stress under dynamic loads, there are issues that need to be taken into account, particularly in terms of the behavior at the interface between the two materials. Using standardized cylindrical 1018 steel specimens uniformly coated with WIP-C1 (Ni/CrC) by cold spraying, this study investigated the fatigue behavior of the specimen as a whole, focusing on the interface areas of the two materials. The fatigue life diagram is given, to a large extent, by the behavior of the base material. As a result, in this work, we have focused not so much on the fatigue behavior of the assembly as on the integrity of the coating material and the defects, failures, etc., that may occur at the interface after a certain number of cycles. The applied load was cyclic fatigue through alternating–symmetric cycles. Scanning optical microscopy was used to observe plastic deformations and crack propagation during the breakage process. It was found that both the base material zone and the cover material zone presented good performance when the maximum stresses were at low values. A fatigue durability curve was also plotted, showing a conventional appearance for a metallic material, slightly influenced by the destruction of the base material interface. At higher maximum stress and, consequently, to large strains, a series of destructions at the interface of the two materials, of different types, were observed and will be highlighted in the paper. [ABSTRACT FROM AUTHOR]

This paper presents research on the degradation processes of the fresco painting in the cave church of Corbii de Piatră Hermitage under the influence of meteoric infiltration water and environmental factors. The medieval fresco dates from the end of the 13th century and the beginning of the 14th century, being painted on a sandstone wall. The infiltration of meteoric water through this wall, the temperature variations, the environment and the repeated wetting/drying processes determined the degradation of the fresco, resulting in its detachment from large surfaces. This research established correlations between the processes that take place, the structural transformations, the changes in composition and the adhesion of the fresco to the sandstone wall. The results have been made available to conservation and restoration specialists, in order to choose appropriate materials and technologies. This paper presents findings regarding the pictorial material and introduces new analysis techniques in research on the degradation processes of the fresco painting in the cave church of Corbii de Piatră Hermitage under the influence of meteoric infiltration water and environmental factors. [ABSTRACT FROM AUTHOR]

Magnesium-based biodegradable alloys used in medical applications have been intensively researched throughout the years. As is well known, the biodegradability of medical alloys is improved by alloying Mg with biocompatible and nontoxic metals. According to studies, Mg, Zn, and Ca are abundant in the human body and help to the regeneration of bone tissue efficiently and effectively. Due to their biodegradability, magnesium alloys, particularly Mg-Ca-Zn alloys used to manufacture implants, reduce patient stress by eliminating the need for a second surgery. Due to magnesium alloys' similar Young's modulus (41-45 GPa) to that of natural bone, the stress shielding effect can be significantly reduced. The objective of this research is to examine the tribological and mechanical properties of a novel experimental biodegradable alloy composed of magnesium (Mg) and 0.5 wt. % Ca, with variable amounts of zinc (Zn) at 0.5, 1.5, and 3.0 wt. %, with the aim of improve the mechanical characteristics. The microstructure and mechanical characteristics were determined using light microscopy (LM), a CETR UMT-2 Tribometer, and an Instron 34SC-5 instrument. A magnesium solid solution as well as a lamellar Mg2Ca and a MgZn2 intermetallic compound were discovered as a result of this research. The tribological parameters exhibit a decrease in coefficient of friction (COF) with increasing Zn concentration and a little increase in hardness and Young modulus up to 3 wt.%. [ABSTRACT FROM AUTHOR]

Ceramic coatings have many advantages for industrial and medical applications due to their exceptional properties. Ceramic coatings with a thickness of approximately 45 μm, after grinding, were grown using a robotic arm that used the atmospheric plasma spraying procedure. The thermal shock stresses—a common situation in applications but difficult to reproduce under laboratory conditions—of the ceramic layers on top of the metal substrate was achieved using solar energy focused by a concentrating mirror, based on experiments conducted in the CNRS-PROMES laboratory, UPR 8521, belonging to the French National Centre for Scientific Research (CNRS). The ceramic layers showed excellent stability at 1000 °C, even at high heating or cooling rates. At high temperatures (above 1800 °C), the exfoliation of the complex ceramic layer was observed. No differences in the structural, phase, mechanical or adhesion properties of the ceramic layer were observed after the thermal shock cycles (in the literature, there have been quite few reports regarding the properties of the ceramic layers after the thermal shock application). Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), atomic force microscopy (AFM) and X-ray diffraction (XRD) techniques were used to characterize the complex ceramic coating and the effects of thermal shock cycling. The phases and chemical composition of the complex coatings remained similar, insensitive to thermal shock at 1000 °C, consisting of a mixture of crystalline yttrium zirconium oxide and α and γ alumina. For all cases, the main residual stress state was tensile. After 5 or 10 cycles of thermal shocks, a smoothing of the residual stress state was observed in the investigated area. A higher temperature (above 1800 °C), applied as thermal shock, led to higher residual stresses and resulted in large cracks and the spallation of the coating layer. [ABSTRACT FROM AUTHOR]