Digitalization and sustainability are important topics for manufacturing industries as they are affecting all parts of the production chain. Various initiatives and approaches are set up to help companies adopt the principles of the fourth industrial revolution with respect sustainability. Within these actions the use of modern maintenance approaches such as Maintenance 4.0 is highlighted as one of the prevailing smart & sustainable manufacturing topics. The goal of this paper is to describe the latest trends within the area of maintenance management from the perspective of the challenges of the fourth industrial revolution and the economic, environmental and social challenges of sustainable development. In this work, intelligent and sustainable maintenance was considered in three perspectives. The first perspective is the historical perspective, in relation to which evolution has been presented in the approach to maintenance in accordance with the development of production engineering. The next perspective is the development perspective, which presents historical perspectives on maintenance data and data-driven maintenance technology. The third perspective, presents maintenance in the context of the dimensions of sustainable development and potential opportunities for including data-driven maintenance technology in the implementation of the economic, environmental and social challenges of sustainable production.

The paper critically investigates about the influence of emulsion mist cooling on the conditions of heat absorption from the machining zone. The cooling conditions under which the total number of drops falling on the hot surfaces of the machining zone evaporate have been studied. The state of cutting wedges made of P25 sintered carbide after finish turning of two-phase pearlite-ferrite AISI 1045 steel with the presence of an anti-seizure and anti-wear additive has been subjected to scanning inspection. In the contact area, the content of surface active compounds is much larger as compared to the areas beyond the contact. It has been observed that the concentration of active compounds on the surface grows by about three times. This phenomena provides confirmatory evidences of favourable machining conditions.

The objective of the investigation was to identify microhardness of surface integrity (SI) after turning with wedges of coated sintered carbide. SI is important in determining corrosion resistance, and also in fatigue crack initiation. The investigation included microhardness analyses in dry and wet machining of duplex stainless steel. The microhardness of SI for various cutting speeds was compared. It has been shown that wet cutting leads to the decrease of SI hardening depth, while increasing the rounded cutting edge radius of the wedge increases the maximum microhardness values and the hardening depth. An infinite focus measurement machine has been used for the rounded cutting edge radius analysis. The study has been performed within a production facility during the production of electric motor parts and deep-well pumps as well as explosively cladded sheets.

This study investigated the production of Cu²⁺-doped CoFe₂O₄ nanoparticles (CFO NPs) using a facile sol−gel technique. The impact of Cu²⁺ doping on the lattice parameters, morphology, optical properties, and electrical properties of CFO NPs was investigated for applications in electrical devices. The XRD analysis revealed the formation of spinel-phased crystalline structures of the specimens with no impurity phases. The average grain size, lattice constant, cell volume, and porosity were measured in the range of 4.55–7.07 nm, 8.1770–8.1097 Å, 546.7414–533.3525 ų, and 8.77–6.93%, respectively. The SEM analysis revealed a change in morphology of the specimens with a rise in Cu²⁺ content. The particles started gaining a defined shape and size with a rise in Cu²⁺ doping. The Cu_0.12Co_0.88Fe₂O₄ NPs revealed clear grain boundaries with the least agglomeration. The energy band gap declined from 3.98 eV to 3.21 eV with a shift in Cu²⁺ concentration from 0.4 to 0.12. The electrical studies showed that doping a trace amount of Cu²⁺ improved the electrical properties of the CFO NPs without producing any structural distortions. The conductivity of the Cu²⁺-doped CFO NPs increased from 6.66 × 10⁻¹⁰ to 5.26 × 10⁻⁶ ℧ cm⁻¹ with a rise in Cu²⁺ concentration. The improved structural and electrical characteristics of the prepared Cu²⁺-doped CFO NPs made them a suitable candidate for electrical devices, diodes, and sensor technology applications.

AISI 316L stainless steel (SS) is one of the extensively used biomaterials to produce implants and medical devices. It provides a low-cost solution with ample mechanical properties, corrosion resistance, and biocompatibility compared to its counterpart materials. However, the implants made of this material are subjected to a short life span in human physiological conditions leading to the leaching of metal ions, thus limiting its use as a biomaterial. In this research, the addition of boron, titanium, and niobium with varying concentrations in the SS matrix has been explored. This paper explores the impact of material composition on modified SS alloy’s physical and mechanical properties. The study’s outcomes specify that the microhardness increases for all the alloy compositions, with a maximum increase of 64.68% for the 2 wt.% niobium added SS alloy. On the other hand, the tensile strength decreased to 297.40 MPa for the alloy containing 0.25 wt.% boron and 2 wt.% titanium additions compared to a tensile strength of 572.50 MPa for pure SS. The compression strength increased from 776 MPa for pure SS to 1408 MPa for the alloy containing niobium and titanium additions in equal concentrations.