Qualitative Research of Composite Graphene Membranes Using the Electric Mode in SEM and AFM.

The development of new graphene-based materials necessitates the application of suitable material imaging techniques, especially for the identification of defects in the graphene structure and its continuity. For this purpose, it is natural to use one of the main properties of graphene-electrical conductivity. In this work, we prepare a 9 cm large-area monolayer graphene membrane on porous scaffolding sealed with either GO or rGO.

Organic Optocoupler with Simple Construction as an Effective Linear Current Transceiver.

In this study, it is shown that an efficient organic optocoupler (OPC) can be fabricated using commercially available and solution-processable organic semiconductors. The transmitter is a single-active-layer organic light-emitting diode (OLED) made from a well-known polyparavinylene derivative, Super Yellow. The receiver is an organic light-emitting diode (OLSD) with a single active layer consisting of a mixture of the polymer donor PTB7-Th and the low-molecular-weight acceptor ITIC; the receiver operates without an applied reverse voltage.

Application of Machine Learning to the Prediction of Surface Roughness in the Milling Process on the Basis of Sensor Signals.

This article presents an investigation of the use of machine learning methodologies for the prediction of surface roughness in milling operations, using sensor data as the primary source of information. The sensors, which included current transformers, a microphone, and displacement sensors, captured comprehensive machining signals at a frequency of 10 kHz. The signals were subjected to preprocessing using the Savitzky-Golay filter, with the objective of isolating relevant moments of active material machining and reducing noise.

Innovative Approaches to Material Selection and Testing in Additive Manufacturing.

This study focuses on selecting a suitable 3D printer and defining experimental methods to gather the necessary data for determining the optimal filament material for printing components of the VEX GO and VEX IQ robotic kits. The aim is to obtain the required data to identify an appropriate filament material and set 3D printing parameters to achieve the desired mechanical properties of the parts while maintaining cost-effectiveness. Another key objective is achieving optimal operational functionality, ensuring the required part performance with minimal printing costs.

Experimental Study on the Elastic Support in a Discrete Rail Fastening System Used in Ballastless Tram Track Structures.

This paper presents an experimental study on the elastic support in a discrete rail fastening system used in a ballastless tram track structure. The study focuses on the elastic support of the anchor element, specifically the Pm49 baseplate. These elements significantly influence environmental pollution along tram routes, such as vibration (at low frequencies) or noise (at high frequencies), as well as static and dynamic rail deflections.

Mathematical Models of Grinding Forces in the Hob Cutter Sharpening Process.

The article presents the results of research aimed at developing mathematical models for determining the components of grinding force occurring during the sharpening of the rake face of hob cutters. The development of the models was based on the results obtained during experimental tests conducted in the first stage of the research. The studies were carried out using a tool grinder and an aluminum oxide grinding wheel.

Improved Voltammetric Procedure for Chloride Determination in Highly Acidic Media.

Cyclic voltammetry (CV) can be applied as a reliable method for the determination of chloride ions in a range from several to a couple hundred (about 200) ppm. Since the standard potential of chloride ion/gaseous chlorine is 1.36 V vs.

Sustainable Infrastructure: Recycled Concrete Aggregates for Cycle Paths.

The application of recycled concrete aggregates (RCAs) has become increasingly popular for different types of structures, as presented in several studies. However, depending on the type of structure and the region, RCAs might have different properties. This study aims to investigate the application of RCAs of different origins for substructure layers of the cycle paths located in Central Europe, which was not analysed previously.

Failure and Degradation Mechanisms of Steel Pipelines: Analysis and Development of Effective Preventive Strategies.

The increasing challenges related to the reliability and durability of steel pipeline infrastructure necessitate a detailed understanding of degradation and failure mechanisms. This study focuses on selective corrosion and erosion as critical factors, analyzing their impact on pipeline integrity using advanced methods, including macroscopic analysis, corrosion testing, microscopic examination, tensile strength testing, and finite element method (FEM) modeling. Selective corrosion in the heat-affected zones (HAZs) of longitudinal welds was identified as the dominant degradation mechanism, with pit depths reaching up to 6 mm, leading to tensile strength reductions of 30%.

Preparation Process of In Situ MgB Material with Ex Situ MgB Barrier to Obtain Long Sections of Superconducting Multicore Wires.

In the present study, our emphasis was directed towards the fabrication process of long multi-core superconducting wires, each spanning several hundred meters. These wires feature an in situ MgB core, an ex situ MgB barrier, and a copper shield. The cost-effectiveness of these constituent materials, coupled with a judicious arrangement of internal components, facilitates the utilization of an economical shielding material for the resulting wire.

Chromium Substitution Extraction Method for Its Recovery from Chromium-Tanned Leather Waste.

The leather industry generates significant amounts of waste, including chromium-tanned leather waste (CTLW), which poses environmental and health hazards due to chromium's potential toxicity. Efficient management of CTLW is crucial for environmental sustainability and resource recovery. Various methods exist for chromium recovery, including physical, chemical, and biological processes, with chemical methods, particularly substitution extraction using organic acids, showing promising results.

The Use of 3D Printing Filaments to Build Moisture Sensors in Porous Materials.

This study explores the application of materials used in 3D printing to manufacture the housings of non-invasive sensors employed in measurements using a TDR (Time Domain Reflectometry) meter. The research investigates whether sensors designed with 3D printing technology can serve as viable alternatives to conventional invasive and non-invasive sensors. This study focuses on innovative approaches to designing humidity sensors, utilizing Fused Deposition Modeling (FDM) technology to create housings for non-invasive sensors compatible with TDR devices.

Thermal Optimization of Edge-Emitting Lasers Arrays.

This paper presents a novel approach to address the issue of uneven temperature distribution in one-dimensional laser arrays, specifically in gallium nitride edge-emitting lasers emitting green light of 540 nm. The results were obtained using heat flow numerical analysis, which included an optimization method specifically developed for this type of array. It was demonstrated that thermal optimization of a one-dimensional edge-emitting laser array can be achieved by adjusting the placement of the emitters within the array and the size of the top gold contact, without changing the overall dimensions of the device.

Analysis of the Influence of Manufacturing Technology on Selected Static, Fatigue and Morphological Properties of CFRP Composites.

The aim of this study was to compare the mechanical properties of carbon-fiber-reinforced polymer (CFRP) composites produced using three popular technologies. The tests were performed on composites produced from prepregs in an autoclave, the next variant is composites produced using the infusion method, and the third variant concerns composites produced using the vacuum-assisted hand lay-up method. For each variant, flat plates with dimensions of 1000 mm × 1000 mm were produced while maintaining similar material properties and fabric arrangement configuration.

Interphase Influence on the Effective Thermal Conductivity Coefficients of Fiber Composites.

This study proposes a two-scale approach to determining the effective thermal conductivity of fibrous composite materials. The analysis was first carried out at the fiber-interphase level to calculate the effective thermal conductivity of this system, and next at the whole composite structure level. At both scales, the system behavior was analyzed using the finite element method.

3D Scanning of Wood-Plastic Composite Decking After Cyclic Thermal Action.

Wood-plastic composites (WPC) combine the properties of polymers and wood, providing an attractive alternative to traditional materials, particularly for terrace flooring. When exposed to various environmental conditions, WPCs are affected by factors, such as water and ultraviolet (UV) radiation. Although most test methods for assessing the durability of these products have focused on changes in mechanical properties and linear dimensions, out-of-plane deformations (concavity and convexity) are often overlooked.

Design Optimization of the Mechanics of a Metamaterial-Based Prosthetic Foot.

This paper is dedicated to the analysis of a foot prosthesis optimization process, with a particular focus on the application of optimization algorithms and unconventional materials, such as auxetic materials. The study aims to enhance prosthesis performance by minimizing the difference between the ground reaction force generated by the prosthetic foot and that of a natural limb. In the initial part of the study, the basic topics concerning the parameterization of the foot prosthesis geometry and the preparation of a finite element model for human gait are discussed.

Analyzing the Vibration Response of Adhesively Bonded Composite Cantilevers.

In this study, we investigated the vibration of adhesively bonded composite cantilevers consisting of two beech wood lamella and a bondline of flexible polyurethane. The beams had a constant total height, while the thickness of the adhesive layer varied. We analyzed both the driven and free vibration of a single cantilever beam and a cantilever with an additional mass attached to its end.

Alkali-Activated Permeable Concretes with Agro-Industrial Wastes for a Sustainable Built Environment.

This research presents a proposal for alkali-activated permeable concrete composites with the use of industrial by-products, including ground granulated blast-furnace slag (GGBS) and waste-foundry sand, as well as agro-desecrate product, i.e., sugarcane bagasse ash (SBA).

Ultrasound-Assisted Synthesis of SnS Quantum Dots Using Acetone as Solvent.

A sonochemical synthesis of SnS quantum dots using acetone as a solvent is investigated. Two different tin sources (SnCl∙2HO or SnCl∙5HO) as well as two different sulfur sources (thioacetamide or NaSO) were applied. The sonication time was also varied between 60 and 120 min.

Analysis of Tool Wear in Finish Turning of Titanium Alloy Ti-6Al-4V Under Minimum Quantity Lubrication Conditions Observed with Recurrence Quantification Analysis.

Titanium alloys, particularly Ti-6Al-4V, are widely used in many industries due to their high strength, low density, and corrosion resistance. However, machining these materials is challenging due to high strength at elevated temperatures, low thermal conductivity, and high chemical reactivity. This study investigates Recurrence Plot (RP) and Recurrence Quantification Analysis (RQA) to analyze tool wear during the finish turning of Ti-6Al-4V.

Energy Efficiency in Turning: A Comparative Analysis of Screw Drive and Linear Drive CNC Machine Tools.

This paper presents a comparative analysis of the energy efficiency of screw drive and linear drive CNC machine tools in turning operations. Two CNC lathes were investigated, one equipped with screw drives and the other with linear drives, during the turning of specially prepared parts. The research examines active and reactive energy consumption, offering insights into the energy efficiency of different drive technologies.

Improvement of Bending Stiffness of Timber Beams with Ultra-High-Modulus-Carbon-Fibre-Reinforced Polymer Sheets.

The bending stiffness of beams represents a pivotal parameter influencing both the dimensions of the elements during their design and their subsequent utilisation. It is evident that excessive deflections can cause discomfort to users and contribute to further structural degradation. The objective of this study was to enhance the bending stiffness of timber beams by bonding a composite sheet to their external surfaces.

The Effect of the Addition of Silicon Dioxide Particles on the Tribological Performance of Vegetable Oils in HCT600X+Z/145Cr46 Steel Contacts in the Deep-Drawing Process.

Friction is an unfavourable phenomenon in deep-drawing forming processes because it hinders the deformation processes and causes deterioration of the surface quality of drawpieces. One way to reduce the unfavourable effect of friction in deep-drawing processes is to use lubricants with the addition of hard particles. For this reason, this article presents the results of friction tests of dual-phase HCT600X+Z steel sheets using the flat die strip drawing test.

Impact of Column Support Stiffness on the Mechanical Performance of Flat Frame Structural Systems Supporting Thin-Walled Folded Roofs.

This article presents a new parametric method for shaping flat transverse frame structural systems supporting thin-walled roofs made of flat sheets folded unidirectionally and transformed elastically to various shell forms. The parameterization was limited to one independent variable, that is the stiffness of the support joints. For different discrete values of simulated stiffness, the surface areas of the cross sections of the tensile and compressed elements and the section modulus of the bending elements were calculated so as to obtain the optimized work of the frame and its elements in the assumed load environment.