The domain of third-generation photovoltaics, mainly perovskite solar cells (PSCs), has been a topic of intensive research due to its varied and renowned efficiency values. However, the concern of stability and long-term operational abilities is a subject that needs to be looked into very differently. Thus, Metal Oxide Electron Transport Materials (MO ETMs) evolved. This review explains the employment of MO ETMs in various PSC architectures, the different deposition methods, requirements of an ideal MO ETM, the common materials that have been used previously, strategies to improve MO ETM-based device performance and lastly, techniques to find and synthesize an appropriate MO ETM. The entire review depicts how one can find alternative approaches to the traditional methods/materials used in a PSC. Moreover, it also highlights the various barriers to commercialization and how one can overcome them using varied approaches like molecular engineering, bilayer techniques and so on, to produce efficient and stable devices.

Chitosan as natural biomaterial is used in tissue engineering and regenerative medicine as a biomaterial alone, as well as in combination with other polymers. The recent research to obtain functionalized chitosan has also focused on the use of environmentally friendly natural resources, introducing different plants, for which new properties and applications in various modern fields have been highlighted. The use of hydro-alcoholic extracts and essential oils from plants to the production of functionalized chitosan-based materials (membranes, films, nanoparticles) shown improved antimicrobial properties and the use of these materials in various fields (medicine, food, industry, cosmetics and environment). The most valuable sources of natural compounds come from plants, being represented by a wide class of phenolic substances that can appear in all parts of plants in fresh or in dried form, extracts or essential oils from seeds, nuts, fruits, vegetables, leaves, roots or even from the stem and bark. The characterisation of membranes and films incorporating chitosan and plants extracts are referring of physical characterisation, structural, morphological structure, mechanical and biological properties based on their antimicrobial potential.

By substituting various kinds of cellulosic fibers with synthetic ones, it is possible to create composites that are better for the environment. Pinewood, coir, sisal, plantains, abaca, and banana fibers are all suitable sources of material. The strength of adhesion between the matrix polymer and fiber is the most crucial element in finding appropriate fiber reinforcement in composites. Plantain (Musa parasidica) fibers were treated with an alkaline solution at various concentrations for varying soaking times. An Instron testing machine and a scanning electron microscope (SEM) were utilized to determine the effect of this chemical alteration on the mechanical characteristics and surface morphology of the fiber. Following treatment, fibers had an improved surface roughness and reached an optimal tensile strength of 651MPa, according to micrographs taken with a scanning electron microscope.

The article presents the main aspects of the implementation, use and pilot and industrial experiments of some self-contained recovery burners. The results of pilot and industrial experiments of these burners have argued and quantified their energy efficiency. This efficiency consists mainly in an economy of specific fuel consumption (natural gas and / or coke gas) of approx. 25-35%. Other advantages of using recuperative burners are: ensuring a higher temperature in the hearth, reducing the duration of the processing cycle and thus increasing labor productivity. All these advantages of using recuperative burners are based on their operating principle, which consists in preheating the oxidizer (combustion air) by recovering an important part of the enthalpy of its own flue gases. This recovery is done in an energy recuperator designed right in the body of the recuperative burner. Due to this important aspect, the recovery burner is part of the Primary Energy Recovery (REP) category.

This study is a report of the results of metallographic study of 5 bronze pieces found in Jeyran Tepe dating back to the Iron Age II. Jeyran Tepe is located 250 m southwest of Ozbaki as one of its hills. The obtained metal pieces included bracelets, necklaces and hairpins, which were used for decoration. The objective of this article was to identify the process of bronze production and study the structure and composition of the components of metal pieces, Iron Age in Jeyran Tepe, based on laboratory studies that have addressed questions in the field of elemental compositions and the method of bronze production in the study area. For this purpose, five bronze pieces were studied using vegetative electron microscope with scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) analysis, metallographic studies at 200 × magnification and X-Ray diffraction (XRD) to identify the chemical composition, metal production technique and type of alloy. The results of XSEM-EDS on the metal background of the samples showed that the constituent elements of these metals are oxygen, copper, tin, silicon, chlorine, sulfur, aluminum, magnesium and carbon. The main reported elements are copper and tin, so metals are made of pure copper and copper-tin alloys. The different amount of tin in bronze pieces of Jeyran Tepe could be due to uncontrolled extraction and alloying methods.

Injection moulding of grain-reinforced and fibre-reinforced polymers exposes the injection moulding tool to severe wear. The microstructure of the tool affects its hardness, wear resistance and the tool life. In this work were studied two different heat treatment technologies effects on the properties of Böhler M340 ISOPLAST steel, which was manufactured by electroslag remelting. There were studied the hardness, the toughness and the microstructure. At sample which was triple tempered after conventional quench to room temperature appears some residual austenite in tempered martensite, near primary and secondary carbides, at cryogenically quenched sample higher hardness and no residual austenite was observed. The results show that cryogenically quenching and triple tempering at high temperature gives the injection moulding tool longer life than conventional heat treatment.