The growing demand for sustainable and environmentally friendly materials has spurred interest in green synthesis approaches for bioactive compounds. In this study, nano-hydroxyapatite (nHA) was synthesized from fish scale biowaste via a top-down mechanical milling method. Fish scales, a renewable and calcium/phosphate-rich waste product, were first calcined to produce FsHA and then subjected to ball milling to produce nanoscale FsHA particles. The resulting material was characterized using particle size analysis, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). FTIR analysis on ball-milled FsHA revealed the presence of HA peaks together with carbonate absorption bands, confirming the presence of B-type carbonate substitutions, indicating partial replacement of phosphate groups by carbonate ions. The presence of C-H groups indicates the potential for polyethylene (PE) contamination originating from the milling container. XRD analysis revealed a pronounced reduction in crystallinity and peak intensity, consistent with a reduction in crystallite size, lattice distortion, and partial amorphization induced by mechanical stress and carbonate incorporation. TEM and STEM imaging verified particle sizes in the 20–200 nm range but also revealed severe agglomeration and the presence of nanoplastic debris (4–5 nm), generated by abrasion of the PE container during milling. These results highlight the dual influence of milling conditions and container material on the purity, stability, and dispersion of biogenic nHA, emphasizing the importance of careful material selection in preventing unwanted contamination and preserving functionality for biomedical applications.
Surface roughness is a critical parameter that measures the overall surface quality of a machined component. Most surface roughness measurement techniques are usually time-consuming to set up and measure, and require specialized equipment. This study proposes an alternative method for measuring the expected surface roughness on a machined component by utilizing the programming interface of a commercially available Computer-Aided Design (CAD) system. In contrast to the standard CAD models that the manufacturers provide, which usually lack critical geometrical aspects, the proposed algorithm takes into consideration the full geometry of the cutting tool, which influences the surface profile to a great extent. The CAD system utilized is a generic software, namely SolidWorks™. Specifically, the Application Programming Interface (API) and its methods were used to develop the algorithm that can simulate the kinematics of the machining process. The selected process is the external turning. Additionally, the surface profile, topography, as well as standard measurements were generated. All data were acquired with respect to typical machining parameters such as the depth of cut, feed rate, and cutting speed. Finally, to verify the accuracy of the algorithm, a set of nine cutting tests was carried out, under a widely used range of conditions, suggested by the tool manufacturer. Concluding, the experimental and the simulated measurements were compared in terms of the Ra, Rz, and Rt surface roughness values. The increased correlation percentages, exceeding 90% in most cases, proved the validity of the developed algorithm.
The advancements in modern manufacturing technologies have made it possible to create customized, distinctive, and personalized products in single quantities or small batches tailored to the individual needs of customers, a process commonly referred to as "customization." However, this has introduced challenges in effectively planning production activities and manufacturing customized products, as it requires balancing customer demands with manufacturing capabilities. In addition to traditional production methods such as turning and milling, innovative techniques like laser cutting-particularly when coupled with a robotic arm-offer enhanced flexibility for producing specialized custom products and intricate patterns. This ability has contributed to laser cutting’s rise as a competitive and widely supported method in modern manufacturing. A significant challenge in this domain is the dynamic nature of task execution in manufacturing, which can render cutting lines obsolete and often requires modifications at short intervals. These changes are driven by factors such as evolving customer requirements, shifts in materials, and new production orders. As a result, it is crucial to continually assess and implement the necessary adjustments to maintain process efficiency and ensure the smooth execution of planned activities. This article explores the application of laser cutting on various materials, such as tulle, and presents the results obtained. The objective was to develop a cutting technology suitable for manufacturing specific types of ion membranes that meet required quality standards and chemical purity levels. Additionally, an analysis using an Ishikawa diagram was conducted to identify areas for improving the quality of the cutting elements.
Balancing of railways is very important for transport and safety. Tamping tools, picks, are balancing tools used together with Tamping machines. The production of these tools, which are used in an average of 12000 pieces per year, is very important for the national economy. From this point of view, the moulds required for the production of compaction tools used in the correction of railways were designed and analyzed. For this purpose, a closed mould of 41Cr4 steel was designed and selected for shaping the compaction tool, and FEA was carried out. Two moulds were modelled for the body connection and shovel parts. The pressing process temperature was determined as 600 oC, and the required pressing force was determined to be 250 MPa from FE analysis to minimize the effect of temperature on the microstructure. In FE analysis, parameters such as stress, strain, temperature, and metal flow were examined, and the highest stress value in the pressing process of the sphere part was found to be approximately 705 MPa at 30% deformation, and the maximum effective plastic strain was determined as 1.88 at 70% deformation. The temperature change was 684 oC in the forming of the body part and 647 oC in the forming of the sphere part. Metal flow was recorded as 271 mm/s at a 30% deformation value, where the maximum deformation occurred, and 135 mm/s in the shaping of the sphere part. The first stage for the production of tamping tool inserts, the pressing method in closed moulds, has been completed and presented in the literature.
Ergonomics is a crucial element in industrial engineering, contributing to the optimization of production processes while ensuring safe, sustainable, and efficient working conditions. This study focuses on simulation-supported ergonomic improvements within the production system of a selected manufacturing company. The main objective was to identify ergonomic deficiencies and propose solutions to reduce workers' physical strain. A digital model of the existing workstation was created using Tecnomatix Process Simulate software, enabling detailed analysis of worker movements and postures in a virtual environment. The RULA (Rapid Upper Limb Assessment) method was applied to assess postural load before and after implementing proposed improvements. The key intervention involved introducing spring-loaded carts to reduce frequent bending and lifting during material handling. Simulation results showed a significant decrease in the risk of musculoskeletal disorders and improvement in worker posture. The study demonstrates that integrating simulation technologies with ergonomic analysis is an effective approach to enhancing workplace conditions. This method emphasizes the value of incorporating ergonomic design early in workstation planning to improve both safety and production efficiency.
In the article, the influence of thermal gouging process (oxygen jet, plasma arc, covered electrode, arc-air electrode) on the structure and properties of thermomechanically treated fine-grained structural steel S420MC. The influence of these changes on the quality of welds deposited by the GMA (Gas Metal Arc- referred to by its subtypes metal inert gas (MIG) and metal active gas (MAG)) method in grooves with and without oxide removal was also shown. Visual, magnetic particle inspection, macroscopic, microscopic tests, and hardness measurements were performed. It has been shown that the highest quality grooves are obtained by gouging with an oxygen jet, while the lowest quality is obtained by gouging with coated electrodes. As a result of the thermal cycle of the gouging processes, a ferritic-bainitic structure is formed at the groove surface, while in the HAZ area, the grain is refined. The tests carried out have shown that repeated exposure to the thermal cycle of the gouging and surfacing process causes deterioration of the properties of S420 MC steel, especially in the HAZ area. In the case of welding or surfacing of materials prepared by thermal gouging, it is recommended to mechanically remove the oxide layer and residues from the gouging area in order to eliminate defects such as incomplete fusion and porosity.
This study investigates the effects of 3D printing parameters on the shape transformation capabilities of structures fabricated from a composite of 80% PCTG, PET, PTMG, and 20% additives with shape memory properties. Different values of printing speed, infill density, and water temperature after printing have significant effects on the structures of PCTG-based with SMPs that influence the shape memory behaviour. In order to improve the effectiveness and precision of shape recovery under heat stimuli, the research uses the shape memory polymer (SMP) principle to optimize three important parameters, which are printing speed, infill density, and water temperature after printing. Samples were created using fused deposition modeling (FDM) technology across 27 experiments, and their recovery functionality time and thermal responsiveness were then assessed. The project employs Taguchi analysis to analyse the results by using ANOVA method. The results showed that the most important factor influencing shape recovery was the water temperature after printing, which was followed by printing speed and infill density. While lower infill densities improved flexibility and shortened recovery time, higher temperatures led to faster recovery. On the other hand, slower printing speeds lengthened the print time but enhanced interlayer stability and adhesion. A printing speed of 40 mm/s, an infill density of 30%, and a post-printing water temperature of 100°C were found to be the optimal parameter combination, resulting in the quickest recovery time of 7.27 seconds. This study provides important insights for developing 4D printing technologies by highlighting the crucial interaction between printing parameters and external factors in determining the performance of 3D-printed SMP structures. This study fills in gaps in the literature, laying the groundwork for the reliable design and production of smart materials with revolutionary potential.
Selected study focuses on the structural evaluation of a design concept for a river-coastal research-passenger ship, with a maximum length of 44.5 m, by parametric 3D strength analysis and non-linear equilibrium algorithm, under oblique wave scenarios. According to the operation cases, two relevant loading cases are selected, corresponding to the ship’s draught minimum of 1.5 m and maximum of 1.7 m. The ship is for the navigation area corresponding to the river Danube and the Romanian coastal waterway, with a maximum 2.5 m wave height. By design, two constructive versions for the structural elements are analyzed, having the thickness standard 5-7 mm and enhanced 6-8 mm. This study leads to practical results by the strength assessment analysis of the research-passenger ship structure, delivering the polar safety operational limits diagram, and pointing out the significant influence of the selected constructive versions for the ship’s design concept capabilities on the navigation area.
The complexities and concerns that are related to the safe, economic, and effective operations in many industries in the fields of mining, radioactivity, agriculture, and petrol make it very tempting for technicians and researchers to develop tools like the bubble pump to deal with the pumping process safely. A laboratory bubble pump system is built to test the potential impact of the change of system design and operation variables on the performance of the pump. This system includes a 125 cm long and 2.10 cm diameter pipe for the liquid lifting part, while five different diameters are tested for the suction part of the pump, with a fixed 30.0 cm pipe length. The effect of ratio of submergence is also examined for four setup values with gradually increased air pumping rates. The liquid pumping rate showed a proportional increase along with the increase of the suction pipe diameter for each submergence ratio. Also, the liquid pumping rate showed a similar trend with the increase of the submergence ratio for each tested diameter of the suction part of the system. An interesting finding is the possibility of achieving higher liquid pumping rates while imposing low air flow rates by the utilization of high submergence ratio as compared to that possible with a lower submergence ratio. This would mean a lower need for the energy to produce the required air flow. A very good agreement of the laboratory results is determined with the theoretical model of Stenning and Martin, which is applied as a verification base for the precision of the system design and operation to test the performance variables of an air lift pump.
This study focused on the manufacturing of C-36000 brass workpieces at a local manufacturing company, highlighting a significant issue related to the premature wear of machining cutting tools. This wear led to frequent tool replacements and increased downtime, negatively impacting production efficiency. To address this challenge, laser texturing was applied to the endmills used in the brass machining process. The goal was to evaluate laser surface texturing (LST) as a solution to reduce tool wear, extend tool life, and optimize the overall manufacturing process. LST is a modification technique that creates microcavities on tool surfaces. This process has been shown to enhance tool performance in machining operations by improving lubricant retention, reducing friction, and minimizing wear. Additionally, the microcavities formed by LST can promote better lubricant flow, reduce operational temperatures, and ultimately increase the tool's durability and cutting efficiency. In this study, two laser texturing patterns—45°-channels and dimple arrays—were selected based on their potential to optimize lubricant flow and reduce frictional forces that contributed to tool wear. Tests were conducted using a CNC machining center to machine 1,000 brass workpieces. Wear mass loss measurements were taken for both untextured endmills and those with laser-textured surfaces. The results demonstrated that the endmills with 45°-channels experienced an 86% reduction in mass loss compared to the untextured endmills, while the dimple-patterned endmills showed higher mass loss, likely due to fracturing. This finding suggested that the angled channel design was more effective at retaining lubricant and reducing friction. Surface profile analysis further confirmed that the open geometry of the angled channels promoted better lubricant flow and provided additional cutting edges, which contributed to reduced wear. Additionally, these geometries resulted in less than 5 µm depth reduction of textured cavities after the machining tests. The application of LST on endmills is also expected to reduce equipment downtime, which would potentially decrease the number of downtime events from 30 to 4 annually. Therefore, texturing with 45°-channels was found to be a highly effective method for enhancing tool performance and extending tool life in machining processes. The results of this study indicated that laser texturing could significantly reduce tool wear, improve manufacturing efficiency, and optimize production output. This study provided strong evidence that laser texturing was a viable solution for addressing premature wear and minimizing downtime in machining operations.
The Al-Mg system is extensively utilized in engineering applications due to its inherent corrosion resistance and moderate strength levels. However, further enhancement of these properties is essential for their effective deployment in demanding industrial environments. In this context, severe plastic deformation (SPD) methods have emerged as a promising approach for microstructural refinement and property improvement. The present study focuses on evaluating the effect of the constrained groove pressing (CGP) technique on the structural characteristics, mechanical performance, and corrosion behavior of AA5083 alloy. Experimental results demonstrate a progressive refinement in grain size, with a reduction from an original average of 50 μm to approximately 3 μm following four CGP cycles. This microstructural modification is accompanied by notable increases in microhardness and tensile strength, approximately 49% and 32%, respectively, relative to the undeformed material. Corrosion resistance, quantified via electrochemical analysis, also exhibited a substantial improvement, with a corrosion rate reduction indicating an enhancement of around 26%. These results underscore the effectiveness of CGP as a viable processing route for significantly upgrading the functional properties of AA5083, thereby supporting its application in high-performance and corrosion-sensitive industrial sectors.
Three-dimensional (3D) printing, especially using fused deposition modeling (FDM), enables the creation of complex shapes while reducing material waste via a layer-by-layer deposition method. Determining the optimal printing parameters to improve the mechanical properties of printed components is a considerable problem. This study investigates the influence of printing factors, such as layer thickness, infill density, and printing speed, on the tensile and compressive properties of polylactic acid (PLA)-carbon fiber composites. A Taguchi orthogonal array design was utilized to examine nine experimental combinations of printing parameters and their impact on mechanical p. The results demonstrate that a layer thickness of 0.4 mm and an infill density of 80% yield a maximum tensile strength of 54.98 MPa. A layer thickness of 0.3 mm, an infill density of 80%, and a printing speed of 60 mm/s yield a compressive strength of 63.19 MPa. This study offers a thorough examination of parameter interactions and their effects, corroborated by scanning electron microscopy, setting it apart from previous research. The results offer substantial insights for optimizing the FDM process related to PLA-carbon fiber composites.
Programmable logic controllers (PLC) are a main part of modern automated manufacturing systems. However, PLC programming presents a number of technical, organizational, and competency challenges. Therefore, the purpose of this article was to build a framework for virtual prototyping of PLC-based control systems in the FlexSim simulation environment, in accordance with Simulation Model-Based Systems Engineering (SMBSE). This work includes an example of conceptual design of a disassembly station and goes through the application of SIL (Software-in-the-Loop) and HIL (Hardware-in-the-Loop) methods and the Digital Twin of an automated sorting line. Expected results include the implementation of a prototype sorting line that will ensure sorting accuracy and efficiency. A working prototype of a sorting line based on an S7-1200 series PLC and a conveyor belt is also presented, together with conclusive remarks, including achieved sorting accuracy higher than 91.6%
Effective warehouse management plays a key role in optimising supply chain operations and ensuring on-time delivery of goods. As logistics systems become increasingly complex, the need for data-driven approaches and advanced planning tools becomes essential. This work focuses on integrating input data processing and simulation-based modelling for warehouse logistics planning using TX Plant Simulation, a powerful tool for modelling, simulating, and optimising discrete-event logistics systems. The presented article aims to show how accurate input data processing combined with simulation support can contribute to more efficient warehouse layout, improved material flow, and resource optimisation. In our case, this involves the creation and testing of a simulation model of a new warehouse. The first phase involves the collection and analysis of real or realistically generated input data related to warehouse operations, such as inbound and outbound flows, order picking strategies, storage methods, transport routes, and resource utilisation. The data required for the analysis were processed based on data available from previous periods from warehouse management within the original warehouse. This data thus formed a relevant input base for creating a simulation model that replicates real warehouse movements. This data is then cleaned, structured, and prepared for use in a simulation environment. Using TX Plant Simulation, a digital twin of the warehouse system is created to test different planning scenarios. Simulation experiments provide valuable insights into the impact of layout configurations, planning strategies, and process improvements. In addition, simulation allows for the safe testing of optimisation strategies without disrupting real operations. The results highlight the importance of high-quality input data and proper model calibration for reliable simulation results. The simulation findings support decision-making processes in warehouse planning and help identify areas for cost reduction, capacity improvement, and increased operational flexibility. The integration of data analysis and simulation tools proves to be an effective approach to solving real-world challenges in warehouse management. This study confirms the potential of TX Plant Simulation as a decision-support tool in logistics engineering and highlights the value of data-driven planning in the context of modern warehouse systems. The proposed methodology can be applied for academic research and industrial practice for strategic and operational planning of warehouse processes.
Cold air plasma has emerged as an efficient, solvent-free method for polymer surface activation, enabling improved adhesion without altering bulk material characteristics. In fused deposition modeling (FDM), mechanical anisotropy and weak interlayer bonding remain major limitations, particularly along the Z-axis where interface strength dictates overall performance. This study investigates an in-situ, noble-gas-free inductive cold air plasma treatment integrated directly into the FDM workflow for polyethylene terephthalate glycol-modified (PETG). A custom-built resonant plasma jet was used to expose each deposited layer to a controlled surface activation step before deposition of the next. Mechanical characterization of treated and untreated specimens demonstrated a consistent enhancement in flexural behavior, indicating more efficient stress transfer between layers. Tensile testing showed favorable trends without substantial changes in bulk elasticity, supporting the hypothesis that the treatment selectively reinforces interlayer regions rather than modifying the polymer matrix. Optical and fractographic analysis further revealed a shift from interfacial delamination in untreated samples to cohesive fracture patterns in plasma-treated specimens. These findings align with the known mechanisms of plasma-induced surface oxidation, which introduce oxygen-rich functional groups, increase surface energy, and facilitate improved wetting and chain interdiffusion during filament deposition. Overall, the results confirm that in-situ cold air plasma activation provides a practical, scalable, and environmentally friendly strategy to enhance the structural reliability of PETG parts in additive manufacturing while requiring no noble gases or post-processing steps. Keywords: Cold atmospheric plasma; PETG surface treatment; Enhanced interlayer adhesion; FDM mechanical performance; Air-based plasma activation.
Composite materials have been a successful challenge for several decades and will continue to represent particularly innovative solutions and of very important application value in many avant-garde fields with particular applicability, such as the aerospace, automotive, medical, consumer goods industries, and more. Much has been written and will be written about the characteristics of composite materials from now on, characteristics that are sometimes clearly superior to structural materials. One of the problems that needs to be solved and which is at a relatively early stage, refers to the joining of two composite materials or plastics between them. At present, the only viable method, and this under certain conditions, refers to ultrasonic welding. The present research refers to the design of an ultrasonic concentrator, part of an ultrasonic transducer used for welding by this method. For this, determining the geometric shape of the ultrasonic concentrator is extremely important, and as such, it was considered innovatively the use a 3rd degree equation whose coefficients were determined. Further, using this equation, the corresponding curve was drawn using the MATLAB software, the curve used in the practical realization of the ultrasonic concentrator, which in this case also represents the tool used in the welding system.
The efficiency and reliability of pumping systems play a key role in wastewater treatment systems as well as in wastewater disposal systems in general. This paper considers the optimisation of a two-channel centrifugal pump impeller for wastewater applications. The purpose of the study is to increase the hydraulic efficiency of the pump by optimising the geometric parameters of the impeller. The optimisation criterion is increasing the impeller hydraulic efficiency. The original impeller geometry was obtained using CFturbo software. Numerical simulation was carried out in ANSYS CFX. Optimisation of the impeller geometry was performed in the ANSYS optiSLang software package using the Response Surface method. The Evolutionary Algorithm was used as the optimisation algorithm, which allowed an efficient analysis of the design parameter space and finding the optimal solution. As a result of optimisation, an impeller with a hydraulic efficiency of 61.2% was obtained, which exceeds the required hydraulic efficiency of 60% specified in the technical conditions. It should also be noted that the resulting geometry allows wastewater bodies with a diameter of Dp=100 mm to pass through.
It is well known that the analysis of the consequences that the interaction of the ship's body with the navigation environment has on its behaviour is one of the difficult problems of naval architecture. The responsibility of a naval architect is to develop design methodologies and building technologies that, considering the complex actions of the navigation environment, allow the efficient operation of ships, in accordance with their functionality. For ships operating in the proximity of offshore drilling platforms, more than in the case of others, it is essential to anticipate, well know and control the consequences that the navigation environment has on the general behaviour of the ship. The paper aims to make some contributions to solving the complex problem of the movements of a supply ship (understood as a rigid solid with a complex architecture) in the hydrometeorological conditions of the North Sea and Baltic Sea. The aim is to substantiate a model for the analysis of static and dynamic nautical qualities, computer-assisted by advanced software instruments (AutoHydro and Octopus Office). To exemplify the study, a supply ship built in Tulcea Shipyard was used. The authors were interested in modifying the architecture of the original hull by introducing a cylindrical portion in the stern area of the ship. This architectural choice was justified by the need to provide, on the deck, additional spaces for various equipment intended for work near the offshore drilling platforms, and, below deck, additional storage spaces for various purposes. Using the analysis facilities offered by the two software tools mentioned, the consequences that these changes have on nautical qualities have been analysed (the study exemplifies, with comments and interpretations, the hydrostatic diagram and the stability diagrams). The study was computerized by AutoHydro software for the analysis of static nautical qualities. For the analysis of the dynamic behaviour of the wave profile characteristic of the North Sea, with the help of Octopus software, the oscillatory movements of roll and pitch were analysed, both for the original hull and for the modified version. The paper aimed to support the advantages of computerized studies in the initial design phases, without minimizing the importance of tests in towing tanks or sea trials. For scenarios such as the one proposed in this paper (modification of the length of a ship already built, while maintaining the rest of the initial dimensions) the computer-aided study, with software tools specific to the field of naval engineering and navigation, highlights the following advantages: elaboration of various architectural variants, precision in design, speed in the realization of constructive solutions, simulations of the dynamic behaviour on the wave according to various parameters (draft, speed, encounter angle).
Today's world is increasingly relying on electronic products in everyday life, and the advancement of modern technologies. Electronics have become essential in a variety of industries, including medicine, communications, transportation, and entertainment. The basic element of electronic devices is the printed circuit board (PCB), which ensures the stability and proper functioning of electrical systems. As such, the quality and precision of PCB manufacturing are critical to the reliability and durability of electronic devices. The PCB manufacturing process is complex and multi-stage, and quality control plays a vital role in eliminating manufacturing defects. Advanced testing and depanelization technologies are used to achieve maximum precision, separating individual boards from larger production panels. Modern test benches are essential to ensure consistency and reliability in production, enabling automatic defect detection and analysis of component parameters. This article introduces the design and construction of an advanced test bench for testing and depanelizing PCB panels. The main objective of the research was to assess the accuracy of the positioning of the system in different modes of operation and under variable loads. The measurements were made with a high-precision laser sensor P-450-M12 from LEUZE. The analysis showed that the largest deviations occurred in the X-axis, where both the mean and maximum values of MEA errors exceeded the assumed thresholds (0.5 mm and 1–2 mm). Better results were achieved in controlled modes (Smooth and Sectional), especially in the Y and Z axes, confirming the potential of the system as a prototype. Identified sources of problems include, among others, mechanical play, structural susceptibility to vibration, and suboptimal distribution of the center of gravity. In addition, the influence of ambient conditions (e.g., sunlight) on the accuracy of limit sensors was noted. Despite the lack of vibration damping and advanced filtering, the system demonstrated measurement stability under laboratory conditions. The stand currently serves as a prototype proof-of-concept demonstrator and provides a solid basis for further development. Structural modifications, automation of the analysis process, and integration with vision systems are planned. The obtained results do not directly increase the precision, efficiency, or reliability of industrial solutions, but they indicate design directions and potential approaches that can be used in the development of future industrial PCB production systems with higher precision and reliability.
The Deff–MR (effective diffusivity vs. moisture ratio) curve approach, developed by the authors, has been successfully used over the past 15 years to optimize drying regimes for clay-based materials. While its practical value in industrial and laboratory settings is well-established, its theoretical contribution to identifying internal moisture transport mechanisms remains underutilized in broader drying applications. To assess its universal relevance, this study applies Deff–MR curve analysis to digitized drying and shrinkage data from multiple external sources. The data were extracted from literature graphs and reanalysed using the proposed Deff–MR framework. Despite differences in experimental procedures and diffusivity calculation methods, the analysis revealed consistent transition points corresponding to known moisture transport mechanisms, including capillary flow, vapor diffusion, and Knudsen diffusion. These findings support the broader applicability of the Deff–MR method as a diagnostic tool for identifying dominant internal moisture movement mechanisms across different drying scenarios and materials.
