Publications

Response of Materials During Sliding on Various Surface Textures

In the present investigation, basic studies were conducted using Inclined pin-on-plate sliding Tester to understand the role of surface texture of hard material against soft materials during sliding. Soft materials such as Al-Mg alloy, pure Al and pure Mg were used as pins and 080 M40 steel was used as plate in the tests. Two surface parameters of steel plates — roughness and texture — were varied in tests. It was observed that the transfer layer formation and the coefficient of friction which has two components, namely adhesion and plowing component, are controlled by the surface texture of harder material. For the case of Al-Mg alloy, stick-slip phenomenon was absent under both dry and lubricated conditions. However, for the case of Al, it was observed only under lubricated conditions while for the case of Mg, it was observed under both dry and lubricated conditions. Further, it was observed that the amplitude of stick-slip motion primarily depends on plowing component of friction. The plowing component of friction was highest for the surface that promotes plane strain conditions near the surface and was lowest for the surface that promotes plane stress conditions near the surface.

Tribology and Applications of Self-Lubricating Materials

Tribology and Applications of Self-Lubricating Materials provides insight into the complex mechanisms behind the development of self-lubricating materials, which due to their ability to transfer embedded solid lubricants to the contact surface to decrease wear rate and friction in the absence of an external lubricant, make up an important part of engineering materials used today. This book emphasizes an understanding of the tribological nature of different composites such as metal, polymer, and ceramic matrix composites and discusses the compatibility of these composites with specific lubricants. The book also offers a view of advancements in the development of self-lubricating mechanisms and covers the latest technologies in the field.

Selective Laser Processing of B2O3 Coatings: Phase Evolution and Tribological Performance

The role of epoxidation process on improving the oxidative, thermal stability, and tribological performance of mustard oil nano lubricants

This study investigated the potential of inedible mustard oil (MO) (Brassica juncea) as a suitable bio-lubricant for enhanced thermal, oxidative stability, and tribological performance. To improve the MO's oxidative stability, it was subjected to a chemical epoxidation reaction, forming epoxidized mustard oil (EMO). The MO and EMO were evaluated for viscosity, functional groups, wettability, oxidative stability, thermal stability, friction, and wear performance. The epoxidation process resulted in nearly doubling the oxidative stability, as well as improving the thermal stability of the MO. Results showed that the EMO exhibited better lubricating properties than the MO, including lower friction and wear. To further improve the lubrication performance of the EMO, solid lubricant additives (SLAs) were incorporated in various concentrations. These SLAs were graphene nanoplatelets (GNP) and hexagonal boron nitride (hBN). The GNP and hBN nano lubricants reduced friction by 31% and 13% compared to the EMO. The same nano lubricants also lowered wear by 73% and 51% relative to the EMO. The underlying mechanisms behind the improvement in the friction and wear performance were discussed. The EMO can be considered as a suitable base stock for renewable and sustainable energy applications.

Modern Innovations and Applications in Plasma Electrolytic Oxidation Coatings on Aluminum, Magnesium, and Titanium

Plasma electrolytic oxidation (PEO) is an electrochemical surface modification technique for producing dense oxide layers on valve metals. This review compiles the various modifications to the PEO process that have been used to improve the produced coatings and make them suitable for specific applications, with a focus on examples of aluminum, magnesium, and titanium substrates. An overview of the PEO process is given, highlighting the various process parameters and their effects on the final surface. The challenges with light metals that motivate the use of surface modifications are summarized, along with some of the other modifications that attempt to overcome them. Two broad categories of modifications to the PEO process are presented: in situ modifications, influencing the properties of the coating during its formation, and ex situ modifications, augmenting the properties of an already-formed coating. Finally, specific examples of applications for modified PEO processes are discussed, including battery, biomedical, water treatment, and energy production applications.

Tribological interactions of 3D printed polyurethane and polyamide with water-responsive skin model

Abstract 3D printing in the textile and fashion industry is a new emerging technology. Applications of 3D printing for designing clothes and other wearable accessories require tribological and biological understanding of 3D printing plastics against the complex human skin to mitigate skin-friction related ailments such as calluses and blisters. This study provides tribological insight in search of an optimal 3D printable material that has minimal friction against the skin. Two low friction 3D printable materials, thermoplastic polyurethane (TPU) and polyamide (TPA) were chosen and tribological testing was carried out against a water responsive skin model. The skin model was synthesized using a gelatine based model made with cotton and crosslinked with glutaraldehyde. Tribological testing of TPU/TPA against the skin model in dry and wet conditions were made. The higher coefficient of friction (COF) was observed in the wet condition compared to the dry condition. To overcome the higher friction, TPA/TPU-sodium polyacrylate composites were prepared by heat pressing that significantly reduced COF of TPU and TPA by ∼ 40% and 75%, respectively, in wet conditions.

Influence of roughness parameters of harder surface on coefficient of friction and transfer layer formation

Various surface textures, characterised in terms of roughness parameters using an optical profilometer, were produced on the steel plates. Sliding experiments were conducted on the prepared hard steel plate using a soft Al-Mg alloy pin under both dry and lubricated conditions. The contact surfaces were examined using SEM to study the transfer layer formation on the plate surface and damage on the pin surface. Results showed that among the surface roughness parameters, the coefficient of friction and transfer layer formation are strongly controlled by a roughness parameter, namely mean slope of the profile, Δa, regardless of the surface textures.

Tribological study of imidazolium and phosphonium ionic liquid-based lubricants as additives in carboxylic acid-based natural oil: Advancements in environmentally friendly lubricants

Studies on Friction and Transfer Layer Formation When Pure Magnesium Pins Slid at Various Numbers of Cycles on Steel Plates of Different Surface Texture

In the present investigation, various kinds of textures (undirectional, 8-ground, and random,) were attained on a set of steel plate surfaces. The roughness of the textures was varied using different grits of emery papers or polishing powders. Pins made of pure magnesium were then slid against the steel plates at various numbers of cycles (1, 2, 6, 10 and 20) using an inclined pin-on-plate sliding apparatus. In the experiments, it was observed that the coefficient of friction and the formation of a transfer layer depended on the die surface textures under both dry and lubricated conditions. The coefficient of friction increased with number of cycles under dry conditions for all of the textures studied. Under lubricated conditions, however, the coefficient of friction decreased for unidirectional and 8-ground surfaces and increased for random surfaces with the number of cycles. A stick-slip phenomenon was observed under both dry and lubricated conditions. Occurrence of the stick slip behavior depended on the surface texture, the load and the number of cycles. The variation in the coefficient of friction under both dry and lubrication conditions was attributed to changes in the texture of the surfaces during sliding.

STUDIES ON FRICTION IN STEEL-ALUMINUM ALLOY TRIBO-SYSTEM: ROLE OF SURFACE TEXTURE OF THE SOFTER MATERIAL

Surface texture influences friction during sliding contact conditions. In the present investigation, the effect of surface texture of soft materials on friction during sliding against hard materials was studied using an inclined scratch testing system. In the experiments steel balls were slid against aluminum alloy flats of different surface textures and roughness. The surface textures were classified into unidirectional, 8-ground and random. Analysis of the experimental data showed that the friction depends on the softer materials surface texture under both dry and lubricated conditions. The results were also compared with aluminum alloy slid against steel flats of different surface textures and roughness. From the experiments, it can be inferred that the surface textures of both harder and softer materials are important in controlling frictional behavior.

Understanding the Mechanism of Stress Corrosion Cracking Resistance in Stainless Steel Welds Subjected to Laser Shock Peening without Coating for Nuclear Canister Applications

In-Space Manufacturing: Technologies, Challenges, and Future Horizons

In-space manufacturing represents a transformative frontier in space exploration and industrial production, offering the potential to revolutionize how goods are produced and resources are utilized beyond Earth. This paper explores the multifaceted aspects of in-space manufacturing, including its evolution, technologies, challenges, and future prospects, while also addressing ethical and legal dimensions critical to its development. Beginning with an overview of its significance and historical context, this paper underscores key concepts such as resource optimization and the reduction of launch costs. It examines terrestrial and space-based manufacturing processes, emphasizing additive manufacturing, advanced materials processing, autonomous robotic systems, and biomanufacturing for pharmaceuticals. Unique challenges posed by the space environment, such as microgravity, vacuum conditions, and radiation exposure, are analyzed alongside issues related to supply chains, quality assurance, and energy management. Drawing from case studies, including missions aboard the International Space Station, this paper evaluates the lessons learned over six decades of innovation in in-space manufacturing. It further explores the potential for large-scale production to support deep-space missions and assesses the commercial and economic feasibility of these technologies. This paper also delves into the policy, legal, and ethical considerations to address as space-based manufacturing becomes integral to future space exploration and the global space economy. Ultimately, this work provides a comprehensive roadmap for advancing in-space manufacturing technologies and integrating them into humanity’s pursuit of sustainable and scalable space exploration.

Ultrasonic Surface Rolling Process: Properties, Characterization, and Applications

Ultrasonic surface rolling process (USRP) is a novel surface severe plastic deformation (SPD) method that integrates ultrasonic impact peening (UIP) and deep rolling (DR) to enhance the surface integrity and surface mechanical properties of engineering materials. USRP can induce gradient nanostructured surface (GNS) layers on the substrate, providing superior mechanical properties, thus preventing premature material failure. Herein, a comprehensive overview of current-state-of-the art USRP is provided. More specifically, the effect of the USRP on a broad range of materials exclusively used for aerospace, automotive, nuclear, and chemical industries is explained. Furthermore, the effect of USRP on different mechanical properties, such as hardness, tensile, fatigue, wear resistance, residual stress, corrosion resistance, and surface roughness are summarized. In addition, the effect of USRP on grain refinement and the formation of gradient microstructure is discussed. Finally, this study elucidates the application and recent advances of the USRP process.

Advances in Bio-inspired Tribology for Engineering Applications

The effect of particulate additive mixtures on the tribological performance of phosphonium-based ionic liquid lubricants

An explicit finite element model to study the influence of rake angle and friction during orthogonal metal cutting

Recent Advancements in Artificial Intelligence in Battery Recycling

Battery recycling has become increasingly crucial in mitigating environmental pollution and conserving valuable resources. As demand for battery-powered devices rises across industries like automotive, electronics, and renewable energy, efficient recycling is essential. Traditional recycling methods, often reliant on manual labor, suffer from inefficiencies and environmental harm. However, recent artificial intelligence (AI) advancements offer promising solutions to these challenges. This paper reviews the latest developments in AI applications for battery recycling, focusing on methodologies, challenges, and future directions. AI technologies, particularly machine learning and deep learning models, are revolutionizing battery sorting, classification, and disassembly processes. AI-powered systems enhance efficiency by automating tasks such as battery identification, material characterization, and robotic disassembly, reducing human error and occupational hazards. Additionally, integrating AI with advanced sensing technologies like computer vision, spectroscopy, and X-ray imaging allows for precise material characterization and real-time monitoring, optimizing recycling strategies and material recovery rates. Despite these advancements, data quality, scalability, and regulatory compliance must be addressed to realize AI’s full potential in battery recycling. Collaborative efforts across interdisciplinary domains are essential to develop robust, scalable AI-driven recycling solutions, paving the way for a sustainable, circular economy in battery materials.

List of contributors

Advances in 3D Bioprinting: Materials, Processes, and Emerging Applications

Three-dimensional (3D) bioprinting has rapidly emerged as a transformative technology at the interface of biomedical engineering and regenerative medicine. By enabling the spatially controlled deposition of living cells, biomaterials, and bioactive molecules, it offers an unprecedented potential to fabricate functional tissues and potentially whole organs in the future. This review explores recent advances in bioprinting materials, processes, and applications, emphasizing the integration of bioinks, printing methods, and mechanical design principles that underpin tissue functionality. Natural and synthetic biomaterials such as hydrogels (e.g., collagen, alginate), polyethylene glycol (PEG), and polyesters like PLGA are evaluated in terms of biocompatibility, printability, and degradation behavior. Key bioprinting modalities, including extrusion, inkjet, and laser-assisted bioprinting, are compared based on printing resolution, cell viability, and scalability. Structural considerations such as scaffold architecture, mechanical stability, and biomimetic design are discussed in relation to native tissue mechanics and requirements. The review also surveys emerging applications in tissue engineering (e.g., bone, cartilage, skin replacements), organ-on-a-chip systems for drug testing, and patient-specific implants, while addressing persistent challenges such as standardization of biofabrication, regulatory and ethical considerations, and manufacturing scale-up. Finally, future trends, including the integration of artificial intelligence (AI) and robotic automation, multi-material and four-dimensional (4D) bioprinting, and the maturation of personalized bioprinting strategies, are highlighted as pathways toward more autonomous and clinically relevant bioprinting systems. Collectively, these developments signify a paradigm shift in how biological constructs are designed and manufactured, bridging the gap between laboratory research and clinical translation.