Published: biannually | ISSN 2620-0325 | ISSN (online) 2620-147X Editor-in-Chief: Mladomir Milutinović, PhD Subject Areas: 1. Materials and Chemical technologies, 2. Mechanical engineering Advanced Technologies and Materials (ATM) aspires to be an international platform for the publication, promotion, and dissemination of original, novel, scientific, theoretical, or applied research in the field of production engineering and related areas. The journal welcomes contributions that promote the exchange of ideas and knowledge between scientific institutions, research centers, and industry all over the world. Review articles, case studies, and industry-relevant manuscripts that contribute to better scientific understanding and advance the practice of engineering, are encouraged. ATM is published biannually - in June and December. Journal Category M51 (2024)
University of Novi Sad, Faculty of Technical Sciences
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Product quality assurance in Powder Bed Fusion through the application of ML/AI tools: a critical review
Due to complex physical phenomena, which govern the process of Powder Bed Fusion (PBF), the feasibility and repeatability of the PBF production is often put in question, having as consequence unsatisfactory implementation of PBF at the industrial level. For this reason, many different research approaches have been carried out in terms of improving the governance of the process and its quality indicators. The overall boost of the Machine Learning and Artificial Intelligence (ML/AI) tools in the last decade has brought a significant advantage in this aspect, since these tools enable evaluation of massive amounts of data and extraction of complex relations which are not easily recognizable by the human eye or simple statistical tools. This paper provides an analysis of critical aspects of product quality in PBF, then offers a thorough critical review of the most relevant research efforts in the field of product quality assurance in Metal Additive Manufacturing through the application of ML/AI methods, to finally detect the major gaps, opportunities and future lines.
Copyright (c) 2026 Advanced Technologies and Materials https://creativecommons.org/licenses/by/4.0
Predictive Modelling of Building Airtightness for Life CycleBased Assessment of Energy Performance
This paper presents a data-driven approach for assessing building airtightness and infiltration-related energy effects using a predictive mathematical model based on artificial neural networks and preliminary evaluation against blower door measurements. The model enables preliminary estimation of airtightness parameters (e.g., n50) during early design stages, supporting building performance assessment without relying exclusively on costly on-site testing. The research further conceptually integrates predicted infiltration-related energy effects into Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) frameworks, supporting sustainable decision-making. Results indicate that predictive approaches may support energy performance evaluation and contribute to improved building envelope design in early design stages.
Challenges in a Volatile Business Environment – Fundamentals and Case Study of Risk Management in a Manufacturing Company
The production of goods is carried out in production networks. However, this international economic and technical interdependence is subject to numerous risks that are predominantly economic, business, and regulatory in nature, but also brings with it a wide range of technological, environmental, and financial risks. This article describes the effects of such risks on production networks. A case study of an automotive manufacturer illustrates the risk management system for identifying, assessing, and mitigating risks. Risks arising from operations include production, technology, supply chain, and information security risks.
Research Directions for Ergonomic Challenges in Collaborative Human–Robot Workplaces
The integration of collaborative robots into shared workspaces introduces new ergonomic challenges beyond traditional automation. This study provides an integrative synthesis of research on ergonomics in human–robot collaboration, identifying key factors, limitations, and research directions. The results show that ergonomics in collaborative workplaces is a multidimensional and system-level issue, involving physical, cognitive, and organizational aspects. While cobots can reduce physical strain, they may simultaneously increase cognitive and coordination demands. The study highlights the need for integrated, adaptive, and human-centered approaches to support safe and effective collaboration in real industrial environments.
Modeling and Additive Manufacturing of a Rocket Engine Nozzle for Micro-rocket Applications
The paper presents the process of modeling a rocket engine nozzle and the manufacturing method of a nozzle intended for use in micro-rocket propulsion systems. The proposed design–technological solution enables the fabrication of a rocket engine component with reduced mass through the application of a structure that allows optimization of the cooling process during flight. Designs incorporating conformal cooling channels make it possible to reduce weight while maintaining high performance, equal to or at least comparable with that of conventionally used designs manufactured using traditional subtractive methods. The presented solution is based on additive manufacturing technologies.
Fatigue Cracks in the 60-year-old steel Structure of the Bridge
The paper shows the fatigue cracks that appeared in the steel girders under the orthotropic plate inside the bridge structure. During decades of exploitation, fatigue cracks developed both in the base material and in the welded joints of the steel girders. Frequent stress cycles due to increased traffic and occasional overloads caused the cracks to propagate over time. Fatigue cracks propagation shortens the life of the steel structure and drastically affects the structural integrity of the bridge. As an effective tool in the detection and evaluation of fatigue cracks in steel bridges, NDT methods occupy a significant place. Non-destructive field methods used for the purpose of fatigue crack detection were magnetic particle testing and penetrant testing. The non-destructive metallographic method of the replica was used to assess the type of crack, and the examination of the taken replicas was carried out in the laboratory using light optical microscopy. Timely detection and repair of fatigue cracks in steel bridge components are key maintenance activities that can prevent potential failure. The paper lists some of the methods that were used for stop the propagation of fatigue cracks. The aim of the paper is to show some of the "in-situ" methods of identification and repair of fatigue cracks in the steel structure of the bridge after 60 years in service.
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Influence of Infill Density on the Mechanical Properties of FFF 3D-Printed PLA and PLA+CF Materials
Fused Filament Fabrication (FFF) has become one of the most widely adopted additive manufacturing technologies for polymer-based components, particularly for polylactic acid (PLA) and carbon fiber–reinforced PLA (PLA+CF) materials. Among processing and structural parameters, infill density has been identified as a critical factor governing mechanical performance and environmental durability of printed parts. However, experimental findings reported in the literature remain fragmented and are often influenced by interacting process variables, limiting the direct transferability of results to engineering design. This study presents a structured comparative synthesis and analytical review of previously published experimental datasets addressing the influence of infill density on tensile strength, elastic modulus, and failure behavior of FFF-printed PLA and PLA+CF materials. The analysis integrates results from three peer-reviewed studies, including data obtained under dry conditions and after controlled exposure to industrial lubricants. Density-dependent trends are systematically evaluated to identify consistent mechanical responses across different material systems and service environments. The results demonstrate that increasing infill density generally improves tensile strength and stiffness due to reduced internal porosity and enhanced interlayer bonding. However, maximum load-bearing capacity does not always increase monotonically with densification, indicating the presence of optimal intermediate infill ranges. Environmental exposure is shown to cause density-dependent mechanical degradation, with higher infill densities providing improved resistance to lubricant penetration and stiffness loss. PLA+CF exhibits higher stiffness compared to neat PLA, while also showing increased sensitivity to brittle failure mechanisms. The presented synthesis provides design-oriented insights into the role of infill density as a primary structural control parameter, supporting performance optimization of FFF-printed polymer components without modifications to material composition or processing hardware.
Design and Evaluation of a Smart Insole System for RealTime Gait and Plantar Pressure Monitoring
Wearable sensor systems offer new opportunities for continuous, non-invasive monitoring of gait and plantar pressure, providing insights for rehabilitation and mobility assessment. This study presents a lightweight, minimally intrusive smart insole system integrating five force-sensitive resistors, microcontroller-based readout electronics with Bluetooth low energy communication, and a smartphone application for data visualization, storage, and analysis. The microcontroller (nRF52840) samples force sensitive resistor (FSR) signals at 100 Hz, transmits data wirelessly, and is powered by a rechargeable lithium-ion battery housed in a compact 3D-printed enclosure designed for minimal impact on user comfort and mobility. To assess the influence of insole material on sensor performance, testing was conducted using direct sensor insoles and 3D-printed thermoplastic polyurethane (TPU) insoles of two hardness levels (95A and 65A Shore). Results from a subject walking along a defined path demonstrate consistent trends between left and right insoles, while the measured analog-to-digital converter (ADC) signals indicate that softer insole materials reduce peak sensor readings. The proposed system provides a versatile platform for real-time gait monitoring and personalized gait rehabilitation, highlighting the critical interplay between insole material properties and sensor performance.
Copyright (c) 2025 Advanced Technologies and Materials https://creativecommons.org/licenses/by/4.0
Influence of Peak Temperature on the Hardness in the Heat Affected Zone of S700MC, CK45 and S355W Welds
Welding of carbon steels induces significant microstructural modifications within the heat-affected zone (HAZ), which influence the material’s performance during service. These changes are typically associated with increased hardness and reduced toughness. Although often remaining within acceptable limits, they must still be considered, especially when the weld is part of a highly demanding application. Continuous Cooling Transformation (CCT) diagrams, which are typically used to describe heattreatment behaviour, are not fully suitable for welding applications. This is because welding heat cycles differ substantially from quenching: they reach much higher temperatures and include no soaking time. As a result, HAZ hardness depends not only on the cooling rate but also on the heating rate and the peak temperature reached at each point within the HAZ. These parameters govern the transformation of pearlite into austenite and the homogenization of the austenitic phase. This paper investigates the influence of the peak temperature within the HAZ on the hardness of three different steels (S355, C45, and S700MC) under conditions of relatively slow cooling. Samples were heated in a furnace to predefined maximum temperatures and then immediately cooled in an air stream. The results indicate that, beyond a certain temperature, a sharp transition from low to high hardness occurs. This transition is associated with grain coarsening and completion of the austenitization process. Compared to oil quenching, additional features such as the formation of Widmanstätten microstructures were also observed.
Workability Limit Diagram at Plane Stress Condition
Numerous experimental studies of workability limit diagrams in the domain of bulk deformation have been performed on specimens where failure occurs at the free surface, i.e., under plane stress conditions. Previous investigations of workability diagrams using compression tests on axially symmetric specimens have yielded negative values of the stress triaxiality ratio (β < –1), while positive values have predominantly been obtained from tensile tests, often exceeding β > +3. The objective of the present study is to explore the applicability of additional deformation models under plane stress conditions that could extend the workability diagram into regions corresponding to negative stress triaxiality ratio values. Additionally, the study aims to determine the limiting values of the stress triaxiality ratio under such stress conditions. For cold bulk forming processes, the region of the workability diagram associated with negative stress triaxiality ratio values (β < –1) is of particular technological importance. The analysis of various formability tests under plane stress conditions was conducted using idealized deformation models, in which the deformation path was assumed to be linear.
Dual-Response Optimization of Fused Filament Fabrication for Controlling Crystallinity and Tensile Strength in PLA Scaffolds
Fused filament fabrication (FFF) is widely applied in scaffold manufacturing due to its ability to produce porous polymer structures with controlled architecture and reproducible process conditions. In biomedical applications, optimization of mechanical performance must be accompanied by reliable regulation of polymer crystallinity, as excessive crystalline content can adversely affect degradation behaviour and biological response. While previous studies have demonstrated that in-process crystallinity can be manipulated through adjustment of FFF processing parameters, limited attention has been given to crystallinity variance and its implications for process robustness. In this study, a statistically designed experiment was employed to examine the combined influence of extrusion speed, extrusion temperature, layer thickness, and build plate temperature on tensile strength and in-process crystallinity of polylactic acid specimens fabricated by FFF. A varianceaware dual-response optimization framework was implemented to identify parameter combinations that maximize tensile strength while achieving low and stable crystallinity. In addition to mean crystallinity values, crystallinity variance was explicitly analysed to enhance process reproducibility. The results indicate that extrusion speed is the dominant contributor to crystallinity variance, while appropriate parameter selection enables simultaneous attainment of high tensile strength and controlled crystallinity within a narrow and reproducible range. Experimental verification confirmed the predictive capability of the developed models. These findings demonstrate that incorporating variance minimization into multi-objective optimization provides a robust approach to process control, supporting the fabrication of polymer scaffolds suitable for biomedical applications.
Application of Artificial Neural Networks for Modeling Deformation Forces in Open-Die Forging
This paper presents an experimental and modeling study of the deformation force in bulk forming processes conducted in open dies. The research was performed on stepped axisymmetric aluminum alloy (AlMgSi0.5) specimens under hot-working conditions, with forming temperatures ranging from 420 °C to 460 °C. A full factorial experimental design with five input factors—geometrical parameters of the die and workpiece, as well as forming temperature—was applied to investigate their influence on the deformation force. The experimental data were used to develop a predictive model based on Artificial Neural Networks (ANN) using the Deep Learning Toolbox in MATLAB. A feedforward neural network with one hidden layer consisting of ten neurons was trained, validated, and tested. The obtained results showed excellent agreement between the experimental and predicted values, with very high values of the correlation coefficients for all datasets. The high accuracy and generalization ability of the network confirm its suitability for modeling nonlinear relationships in metal forming. The proposed ANN model provides a reliable alternative to complex numerical simulations, enabling efficient prediction of forming forces in open-die forging processes.
Composition, Microstructure, Hardness and Ballistic Properties of a Representative Steel versus Kevlar Military Helmet
Ballistic helmets are essential for protecting against projectiles, fragmentation, and blunt trauma—key contributors to combat fatalities. This study compares the ballistic performance, durability, and cost-efficiency of a tempered martensite steel helmet to a modern Kevlar composite helmet. Through ballistic, mechanical, and metallographic testing, the steel helmet demonstrated comparable protection against pistol and revolver calibers, due to ballistic shape and high quality of steel applied. However, against rifle calibers, both helmets performed similarly, with perforations by 5.56x45 mm and 7.62x39 mm. The paper examines the trade-offs between protection, durability, and cost, highlighting steel helmets as a viable alternative in contemporary protective gear.
Review of Advanced Resistance Welding Technologies and Control Methods for Joining State-of-the-Art Materials in Lightweight and Electric Vehicle Manufacturing
Resistance spot welding (RSW) remains a fundamental joining process in modern industrial manufacturing, particularly in the automotive sector. Ensuring consistent weld quality is critical, prompting the development and integration of various monitoring and control systems. This paper reviews the theoretical foundations of RSW and explores diverse control strategies from a control systems perspective. A comprehensive overview of contemporary quality assurance methods—including those leveraging artificial intelligence and machine vision—is provided. The paper also examines the evolving role of RSW in lightweight automotive design and the production of electric vehicles, where diverse materials and dissimilar metal combinations are increasingly common. To address the challenges of welding these advanced materials, state-of-the-art welding and joining technologies are discussed in detail.
Study of abrasive action on surface roughness and worn mass of laminated composites: production and evaluation
This study examined the effect of abrasive action on the surface roughness and mass loss of laminate composites produced by the wet lay-up method. The paper describes in detail the production process of these composites and after the production process, the surface was analysed using an optical microscope. Surface roughness was monitored in the transverse and longitudinal directions, before and after processing with P3000 grit sandpaper, where a significant increase in roughness was observed with minimal mass loss. A more detailed analysis of mass loss included precise measurements in the time interval from 1 to 5 minutes, with the results showing that with extended grinding time the amount of worn material increases. Additionally, analysis using an optical microscope confirmed the successful production of laminate composites, with very little presence of trapped air bubbles recorded, indicating the high efficiency of the applied production process. Considering the characteristics of the used epoxy resin, the obtained results indicate high wear resistance of laminate composites, which is crucial for achieving aesthetically attractive components.
Tensile-Shear Strength of a Single-lap Adhesive Joint of PA6 GF Composite: Effects of Fiber Orientation and Moisture
One of the main features of additive manufacturing is the ability to produce parts with complex geometries that would be difficult or impossible to produce with minimal waste using conventional manufacturing technologies. A more massive implementation of additive technologies makes it possible to shorten supply chains and reduce the need to store parts. The use of composite materials is massive nowadays, first of all in the lightweight design. The aim of this study is to analyze the influence of fiber orientation and moisture on the strength of single-lap adhesive joints of parts produced by additive manufacturing. The test samples (adherends) were produced using FDM (Fused Deposition Modeling) technology, PA6 GF composite material and two-component epoxy adhesive. Results showed that the average failure load tends to increase the higher the percentage of absorbed moisture in the base material. With the selected combination of material and adhesive, the influence of fiber orientation cannot be observed independently of the amount of moisture absorbed. The best results are achieved with the highest percentage of absorbed moisture and the orientation of the fibers in the direction of the longitudinal axis of the samples.
Sustainable and Eco-friendly Based Hydroxyapatite Particles-Wool Fiber Hybrid Reinforced Epoxy Bio-composites for Biomedical Applications
The rapid growth of the world population and industrialization has led to an unparalleled rise in the generation of wastes from animals in the agricultural and food processing industries among other sectors. Besides this, the concerns for the future create an urgent requirement for sustainable materials that can substitute conventional, non-renewable composites in many applications. Hence, this study investigates the development of bio-composites using animal wastes as reinforcement materials. The research offers an environmentally acceptable process that aid waste management and addition to enhancing the performance of materials for modern day’s applications. Shells and wools were processed to obtain hydroxyapatite particles (HAp) of 18.52 μm sizes and 10 mm long fibers, respectively that were used as reinforcements in epoxy. Stir cast molding in an open mold was used to fabricate the epoxy-based bio-composites with varying proportions of the constituents. Mechanical, wear and microstructural images evaluations revealed and support the use of these bio-reinforcement based materials. The results indicated that wear, hardness and impact strength properties were enhanced with 18 wt.% reinforced composites providing the optimum properties when compared to other weight fractions. It showed optimum values in wear (0.123), hardness (78.4 HS), impact strength (83.1 J/mm2) and maximum flexural strength (85.2 MPa) supporting the recommendation for use as adhesive biomedical materials in biomedical applications such as orthopaedical implants, dental implants, scaffolds, bone repair, wound healing, and periodontal regeneration.
Enhancing Directed Energy Deposited AL5356 Through in Situ Workpiece Vibrations
This study explores an innovative method to enhance Directed Energy Deposition (DED) of aluminum 5356 products by integrating an electromagnetic vibration system into the DED setup. The application of vibrations significantly improved surface quality, reducing surface waviness and increasing building efficiency by 14%, from 78.5% to 92.25%.Gas porosity was reduced from 1.5 ± 0.04% in as-built (AB) components to 0.34 ± 0.07% in vibration-assisted (VA) parts. Tensile tests showed a marked reduction in anisotropy, with the tensile strength deviation between the x and z directions decreasing to less than 0.4% for vibration-assisted samples, compared to 7.9% for as- built ones. Additionally, secondary phase analysis revealed a homogenization effect, with magnesium- and iron-rich precipitates displaying a finer dispersion (3.57 ± 3.42 µm²) compared to 11.28 ± 12.49 µm² in as-built parts. Overall, the findings highlight the potential of vibration-assisted DED to improve part properties, reduce defects, and advance the DED manufacturing process.
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Influence of aging and surface treatments on the fatigue response of L-PBF manufactured steel parts
The processes of metal additive manufacturing (AM) offer advantages over traditional technologies, especially when it comes to producing parts with complex designs. Thanks to the flexibility in manufacturing processes and the relatively high speed of part production, AM technologies can now be found across various industries. A better understanding of the mechanical properties and fatigue behavior of metal parts is crucial for their successful integration in different sectors. Numerous factors play a key role in influencing the fatigue properties of metal parts produced through AM. This study investigates the impact of heat treatment and surface treatment on the fatigue behavior of components made from marginal steel (MS1) and stainless steel (PH1). After subjecting MS1 and PH1 steel to heat treatment, it is expected that the fatigue limits will increase compared to their original state. Additionally, experimental findings show that not only do surface treatments significantly affect fatigue strength when used alone, but also that changing the order of subsequent treatments can either enhance or diminish fatigue strength.
SLA-Based Injection Molding Tool Inserts: Challenges, Innovations, and Future Prospects
Stereolithography (SLA), a key technology in additive manufacturing, has transformed the production of injection molding tool inserts by enabling rapid prototyping and cost-effective small-scale production. SLA utilizes photopolymer resins to fabricate intricate, high-precision molds, reducing lead times and costs. However, challenges such as limited mechanical strength, lower thermal resistance, and slower heat dissipation compared to traditional materials constrain its broader adoption. This paper reviews the application of SLA in injection molding, emphasizing advancements in high-performance resins that improve durability, thermal stability, and mechanical properties. Key factors affecting mold performance, including material flowability, cooling times, and injection pressure, are discussed alongside optimization strategies like modular designs and post-processing techniques. While SLA molds may not rival traditional tools for high-stress applications, they excel in rapid tooling and prototyping. As material and process innovations continue, SLA is poised to play a transformative role in modern injection molding, bridging additive and traditional manufacturing.
Influence of Infill Structure Shape and Density on the Mechanical Properties of FDM 3D-Printed PETG and PETG+CF Materials
This paper investigates the impact of infill structure shape and density on the mechanical properties of Fused Deposition Modelling (FDM) 3D-printed materials, specifically PETG and PETG reinforced with carbon fibers (PETG+CF). The research aims to optimize additive manufacturing processes by examining how different infill geometries—hexagonal, triangular, and linear—and varying infill densities (30%, 60%, and 100%) influence the mechanical strength, tensile properties, and flexibility of the printed components. Experimental tensile tests were conducted on specimens to assess key mechanical parameters including maximum force, break force, Young's modulus, tensile strength, and nominal strain at break. Results indicate that infill shape and density significantly affect the mechanical performance of 3D-printed materials. Hexagonal infill structures demonstrated superior mechanical properties, with a 45.11% increase in maxi-mum force compared to triangular infill structures. Additionally, increasing the infill density from 30% to 100% resulted in a 69.13% increase in maximum force and a 64.87% increase in break force for PETG+CF specimens. These findings provide valuable insights for enhancing the quality and performance of FDM 3D-printed products, offering guidelines for the development of advanced materials with tailored mechanical properties for various industrial applications.
Copyright (c) 2024 Advanced Technologies and Materials https://creativecommons.org/licenses/by/4.0/
Effects of Aging and Refreshment Ratio on the Strength Properties of Selectively Laser Sintered Polyamide 12
This study investigated how the tensile properties of selectively laser-sintered polyamide 12 (PA12) specimens are affected by aging and refresh ratio. Starting with a new powder, printing cycles of approximately ten hours were performed, during which tensile and density specimens were printed. After each cycle, the powder was tested for melt flow index (MFI). In the first part, the best processing direction was determined. It was found that tensile strength, modulus of elasticity, elongation at break and MFI showed a linear trend, with the independent variable being the number of hours at elevated temperature. This was analyzed by linear regression. MFI increased with the number of hours at elevated aging, while all other properties mentioned decreased.
Sustainable and Light Weight Cellulose-Based Hybrid Reinforced Epoxy Composites for Automotive Application
This study focuses on the development and investigation of sustainable and lightweight cellulosebased hybrid reinforced epoxy composites. The research contributes to the ongoing efforts to create durable and biodegradable composite materials for automotive applications. The hybrid composites were fabricated using a hand layup approach, combining sisal/dombeya fiber with paper particles as reinforcements in an epoxy matrix. Prior to incorporation, the fibers underwent mercerization to reduce hydrophilicity. Hybrid composites with 3-15 wt% reinforcements were produced. Mechanical properties, including tensile, flexural, impact, and hardness, were evaluated, and scanning electron microscopy (SEM) was used to examine the surface morphology of fractured composites. Wear resistance, density, and water absorption were also studied. Results demonstrated significant improvements in all properties compared to the unreinforced epoxy matrix. Notably, composites with 9-12 wt% sisal fiber-paper particles (SF-PP) exhibited optimal mechanical properties. Flexural modulus, hardness, tensile and impact strengths were 721 MPa, 67 HS, 32.94 MPa and 46.24 kJ/m2, respectively from 9 wt.% while flexural strength and tensile modulus were of 57.30 MPa and 438.21 MPa, respectively from 12 wt.%. On the other hand, the composite reinforced with 12 wt% dombeya fiber-paper particles (DF-PP) demonstrated superior wear resistance. DF-PP-based composites exhibited low moisture absorptivity and density compared to SF-PP. Conclusively, the study recommends epoxy-based composites reinforced with hybrid sisal fiber and paper particles for automotive components like bumpers and dashboards, while composites reinforced with hybrid dombeya fiber and paper particles are suitable for battery enclosures and wheel covers.
Influence of Some Selected Ceramic Fillers on Rheological, Morphological, Mechanical and Thermal Stability Properties of Rigid Polyurethane Foam
This study investigates the influence of limestone, mica, granite, and kaolin on the properties of polyurethane foam. The selected ceramic fillers were pulverized and sieved to obtain particles smaller than 90 µm that were used as reinforcements in the polyurethane matrix in a randomly dispersed mode. The matrix constituents were mixed in the same ratio while fillers were introduced via a one-shot system approach in predetermined proportions of 3–7 wt. %. The work was carried out to identify the optimum filler to be utilized in the production of improved polyurethane rigid foams. The cream, gel, rise, and tack-free times as the rheological properties were observed as the filler materials were introduced in the polyurethane matrix. Mechanical, water absorption and thermal stability properties were evaluated while the morphology of the filled polyurethane foams was examined with SEM. From the results, it was found that kaolinfilled polyurethane foam produced the optimum rheological, mechanical, water absorption, and thermal stability properties. Hence, particulate kaolin of less than 90 µm can be used in the production of green foam for various applications in health, automobile, and household materials.
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Analysis of Shrinkage in Metal Injection Molding
Maintaining component dimensions in metal injection molding (MIM) is difficult because of significant component shrinkage in the sintering step and shrinkage variation. Most of the shrinkage variation in MIM is due to density inhomogeneity in moldings (greens), induced in the injection molding step. Therefore, the focus of this research was to clarify the relationship between injection molding parameters and shrinkage of a ring-shaped component molded into a four-cavity split mold. Material used in research was Catamold 310N in the form of ready to mold granules. An experiment, according to a 2k factorial design, was performed to evaluate the effects of holding pressure profiling on shrinkage at different levels of coolant temperatures and fill rates. Results showed that the interaction of holding profile and coolant temperature has the most influence on the mean shrinkage. This finding offers a possibility to maintain the component dimensions in MIM by using the revealed interconnection between holding pressure profile and mean shrinkage.
The Stress Strain Analysis of Forward Extrusion Process of Hollow Elements
This paper presents an analysis focused on the stress-strain dynamics within the forward extrusion process for hollow elements. The forward extrusion of hollow elements is characterized by extensive plastic deformation and complex material flow. This process involves splitting the metal continuum, subjecting it to plastic deformation, and merging it into a seamless product with a predetermined cross-sectional shape as it exits the tool. Employing modern numerical finite element methods is essential for designing such processes, as it enables the simulation of metal behavior within the tool. These simulations help predict mechanical parameters within the deformable material continuum, such as stress, strain, temperatures, and strain rates. Additionally, they allow for the optimization of tool designs tailored to the specific product, improving process efficiency and quality. Understanding the stress-strain distribution at individual nodes enables proactive measures to prevent echanical disruptions within the continuum, ensuring the integrity and quality of the final product—an essential criterion in the forward extrusion process for hollow elements.
Copyright (c) 2023 https://creativecommons.org/licenses/by/4.0/
Numerical Determination of the Life of Steel Exposed To Low Cycle Fatigue
In the paper, based on the results of the experimental research of high-strength low-alloy steel(HSLA), Nionicral 70 (NN-70), under conditions of low-cycle fatigue (LCF), a numerical analysis of stress and determination of the life of steel samples was performed. Experimental testing of the behavior of the samples were performed with controlled and fully reversible strain (Δε/2 = const, Rε = εmin/εmax = -1), according to the standard ISO 12106:2003 (E). For computational analyses, the following were used: the method of least squares and the method of finite elements (FEM). On the basis of the analysis of the results of the stress-deformation state and the determination of the life span through the isolines of the life span and comparison with the results of experimental tests, a graphic representation is given. The analysis justified the effort to numerically solve the estimation of the lifespan of steel under low cycle fatigue (LCF).
On Photonic Implementation of Quantum Computers
The first section of the work investigates light modes as a means of implementing optical qubits and qudits. The modes considered are polarization mode, path mode, transverse spatial mode, frequency mode, temporal bin-mode and temporal mode. Subsequently, mathematical model of linear optical elements like beam splitters (BS) and phase shifters are deduced and their capability of representing any single qubit optical gate is exposed. Finally Knill, Laflamme and Milburn (KLM) method of using linear optical elements to promote nonlinear operations based on nonlinear (nondeterministic) sign-flip gate (NS) is explained, and designs of two qubits conditional sign flip gate (c-z1/16) and CNOT gate, both based on KLM method, are demonstrated. So, universal set of quantum gates based on linear optics is possible.
Inductive Heating and Quenching of Planetary Shafts for Diesel Engine Starters
High mechanical and temperature cyclic loading of the final products for automotive, transport, construction and agriculture mechanization industry, demands sufficient mechanical properties of all of their components during its exploitation. Majority of the components is made of steel, by different cold forming processes. Their main demanded characteristics are surface wear resistance and fatigue strength under pulsating stress in combination with cyclic temperature loading, which could be achieved only by appropriate heat treatment. The efficiency of the combined inductive heating and water quenching heat treatment and quality of the planetary shafts were analyzed, with the use of thermographic analysis, hardness measurements, and metallographic examination. Combination of inductive heating and water quenching is the most effective heat treatment process of carbon steel planetary shafts for the diesel engine starters. Long life span of carbon steel planetary shafts it’s essential for their economical production. The replacement of starter is expensive from both: money and working time point of view. Surface temperature measurements during the inductive heating process were performed in the industrial environment. The intensity and homogeneity of the planetary shaft surface temperature field was measured by thermographic camera. On the base of theoretical knowledge and measurements, a mathematical model for temperature conditions determination in the shaft during the entire process of heating and quenching was carried out, and used for analyses and optimization of planetary shafts induction hardening process.
Effect of Copper/Alumina Hybrid Reinforcement on the Microstructure and Mechanical Properties of Stir Cast Aluminum Alloy AA6063
Dear Readers, We wish to inform you that an article titled "Effect of Copper/Alumina Hybrid Reinforcement on the Microstructure and Mechanical Properties of Stir Cast Aluminum Alloy AA6063" has been removed from the Journal of Advanced Technologies and Materials (AT&M). The removal was initiated at the request of the author due to the identification of a conflict of interest that was not appropriately disclosed during the submission process. We acknowledge the importance of maintaining ethical standards in academic publishing and have promptly addressed the author's request to remove the article from our online platform. Upholding transparency and integrity remains our priority, and therefore, we will provide an editorial note or clarification in the upcoming printed issue addressing this matter. We appreciate your understanding and continued support for our dedication to maintaining the credibility and integrity of our journal.