Zinc oxide (ZnO) in various nano forms (nanoparticles, nanorods, nanosheets, nanowires and nanoflowers) has received remarkable attention worldwide for its functional diversity in different fields i.e., paints, cosmetics, coatings, rubber and composites. The purpose of this article is to investigate the role of photocatalytic activity (role of photogenerated radical scavengers) of nano ZnO (nZnO) for the surface activation of polymeric natural fibres especially cotton and their combined effect in photocatalytic applications. Photocatalytic behaviour is a crucial property that enables nZnO as a potential and competitive candidate for commercial applications. The confirmed features of nZnO were characterised by different analytical tools, i.e., scanning electron microscopy (SEM), field emission SEM (FESEM) and elemental detection spectroscopy (EDX). These techniques confirm the size, morphology, structure, crystallinity, shape and dimensions of nZnO. The morphology and size play a crucial role in surface activation of polymeric fibres. In addition, synthesis methods, variables and some of the critical aspects of nZnO that significantly affect the photocatalytic activity are also discussed in detail. This paper delineates a vivid picture to new comers about the significance of nZnO in photocatalytic applications.

Additive manufacturing technologies have a lot of potential advantages for construction application, including increasing geometrical construction flexibility, reducing labor costs, and improving efficiency and safety, and they are in line with the sustainable development policy. However, the full exploitation of additive manufacturing technology for ceramic materials is currently limited. A promising solution in these ranges seems to be geopolymers reinforced by short fibers, but their application requires a better understanding of the behavior of this group of materials. The main objective of the article is to investigate the influence of the microstructure of the material on the mechanical properties of the two types of geopolymer composites (flax and carbon-reinforced) and to compare two methods of production of geopolymer composites (casting and 3D printing). As raw material for the matrix, fly ash from the Skawina coal power plant (located at: Skawina, Lesser Poland, Poland) was used. The provided research includes mechanical properties, microstructure investigations with the use of scanning electron microscope (SEM), confocal microscopy, and atomic force microscope (AFM), chemical and mineralogical (XRD-X-ray diffraction, and XRF-X-ray fluorescence), analysis of bonding in the materials (FT-IR), and nuclear magnetic resonance spectroscopy analysis (NMR). The best mechanical properties were reached for the sample made by simulating 3D printing process for the composite reinforced by flax fibers (48.7 MPa for the compressive strength and 9.4 MPa for flexural strength). The FT-IR, XRF and XRD results show similar composition of all investigated materials. NMR confirms the presence of SiO₄ and AlO₄ tetrahedrons in a three-dimensional structure that is crucial for geopolymer structure. The microscopy observations show a better coherence of the geopolymer made in additive technology to the reinforcement and equal fiber distribution for all investigated materials. The results show the samples made by the additive technology had comparable, or better, properties with those made by a traditional casting method.

The development of environmentally friendly, multifunctional conductive membranes is an ideal candidate for future new electronic components. Some cellulose-based electronic sensors have been studied, such as pressure sensors, hydrothermal sensors, flexible sensors, optoelectronic devices, and electrochemical energy storage, etc. However, there are very few studies on cellulose-based conductive materials in Joule heating. In this study, we adopted a simple and environmentally friendly silane crosslinking method to crosslink cellulose and graphene oxide (GO) together. The cellulose/GO hybrid membrane were characterized by FTIR, Raman, SEM, AFM, TGA, surface wettability, self-cleaning, surface resistance, Joule heating and other tests. Results showed that the covalent bond between cellulose and GO was formed by vinyltrimethoxysilane (VTMS), and GO was successfully cross-linked on the surface of the cellulose membrane. The cellulose/GO hybrid membrane has good thermal stability, strong hydrophobicity and self-cleaning properties. When the GO concentration was 3 w/w%, the Young's modulus of the film reached the maximum (47.38% higher than that of the original sample). In addition, it also exhibited extremely low surface resistivity (720.69 Ω), controllable Joule heating capability, extremely fast thermal response (heating process and cooling process within 5 s) and good electrothermal stability. It showed great potential in multi-functional electronic products such as electric heating electronic devices, electric heating sensors, and smart clothing in the future.

This paper reports on an investigation treating a hard-milled surface as a surface undergoing severe plastic deformation at elevated temperatures. This surface exhibits remarkable magnetic anisotropy (expressed in term of Barkhausen noise). This paper also shows that Barkhausen noise emission in a hard-milled surface is a function of tool wear and the corresponding microstructure transformations initiated in the tool/machined surface interface. The paper discusses the specific character of Barkhausen noise bursts and the unusually high magnitude of Barkhausen noise pulses, especially at a low degree of tool wear. The main causes can be seen in specific structures and the corresponding domain configurations formed during rapid cooling following surface heating. Domains are not randomly but preferentially oriented in the direction of the cutting speed. Barkhausen noise signals (measured in two perpendicular directions such as cutting speed and feed direction) indicate that the mechanism of Bloch wall motion during cyclic magnetization in hard-milled surfaces differs from surfaces produced by grinding cycles or the raw surface after heat treatment.

Secondary and backscaterred electrons are the most common signals used for imaging in the scanning electron microscopy. Generally, SE are used to obtain topographical contrast while BSE show differences in chemical composition (so called Z-con...

The aim of this paper is to compare the mechanical and tribological properties of TiCN and CrCN coatings. These coatings are widely used in industrial applications to improve both friction and wear. They are deposited at the same deposition pa...