Publikační činnost Katedry obrábění, montáže a strojírenské metrologie / Publications of Department of Working and Assembly (346)

Permanent URI for this collectionhttp://hdl.handle.net/10084/71298

Kolekce obsahuje bibliografické záznamy publikační činnosti (článků) akademických pracovníků Katedry obrábění, montáže a strojírenské metrologie (346) v časopisech registrovaných ve Web of Science od roku 2003 po současnost.
Do kolekce jsou zařazeny:
a) publikace, u nichž je v originálních dokumentech jako působiště autora (adresa) uvedena Vysoká škola báňská-Technická univerzita Ostrava (VŠB-TUO),
b) publikace, u nichž v originálních dokumentech není v adrese VŠB-TUO uvedena, ale autoři prokazatelně v době jejich zpracování a uveřejnění působili na VŠB-TUO.

Bibliografické záznamy byly původně vytvořeny v kolekci Publikační činnost akademických pracovníků VŠB-TUO, která sleduje publikování akademických pracovníků od roku 1990.

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Now showing 1 - 20 out of 334 results

Erosive wear behavior of sandstone under low-pressure pulsating water jet
(Elsevier, 2025) Vavro, Leona; Vavro, Martin; Nag, Akash; Klichová, Dagmar; Stolárik, Gabriel; Gupta, Munish Kumar; Hloch, Sergej
The consequences of erosion caused by the mutual interaction of water droplets with sedimentary rock such as sandstone are not satisfactorily elucidated in the literature. This topic is important from many points of view, and its practical applications include the protection of cultural heritage or the targeted removal of material. This study assessed the wear rates on Bozanov sandstone caused by multiple-droplet impingement, with water droplet impact speeds of v = 58 m/s, 92 m/s and 127 m/s corresponding to supply pressure of p = 2, 5 and 10 MPa, respectively. As a droplet generator, a pulsating water jet with a frequency of 20 kHz was used. Water droplets determined by a nozzle diameter d = 1 mm were distributed along a linear trajectory three times for each run. The water droplet impact density was varied by changing the traverse speed. In order to investigate the development of integrity damage, the samples were scanned using a digital microscope. Material loss was determined via weighing and compared using a non-contact measuring method. The results showed that the erosion responses, such as erosion depth and volume removed, increased with an increase in the supply pressure and a decrease in traverse speed. Moreover, it was found that at the lowest supply pressure p = 2 MPa, the effect of the number of drops density is invariant for traverse speeds in the range of 1-10 mm/s. When the pressure was increased from 5 to 10 MPa, the material removal values tripled. This significant increase may be attributed to the formation of an abrasive pulsating water stream within the created groove.
Enhancing surface quality of M300 maraging steel components produced via selective laser melting: a comparison of tumbling techniques
(Springer Nature, 2026) Mechali, Abdesselam; Hlinka, Josef; Sajgalik, Michal; Hajnyš, Jiří; Zelinka, Jan; Měsíček, Jakub; Rizk-Allah, Rizk M.; Sternadelová, Kristýna; Drbúl, Mário; Čep, Robert; Jadlovec, Marek; Petrovic, Marin; Petrů, Jana
This study investigates the effects of centrifugal and vibratory tumbling on the surface quality of M300 maraging steel components produced using Selective Laser Melting (SLM). Surface roughness is a critical issue in SLM, impacting mechanical properties and overall performance. To address this, two abrasive finishing methods were applied using ceramic, plastic, and porcelain media. Evaluations were performed using 2D and 3D surface roughness measurements, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and wettability analysis. Centrifugal tumbling, particularly with ceramic media, demonstrated significant effectiveness in reducing surface roughness, achieving an Sa value as low as 0.39 mu m. In contrast, vibratory tumbling showed limited improvement. EDS analysis highlighted a reduction in titanium content and an increase in silicon concentration, likely due to surface layer removal and media interaction. Wettability analysis further confirmed enhanced surface properties, with a reduced contact angle of 60 degrees, promoting better adhesion. These findings emphasize the superiority of centrifugal tumbling for enhancing surface quality in SLM-printed M300 maraging steel components. This cost-effective post-processing technique offers practical applications for industries seeking improved surface integrity and functional performance in critical components.
Effect of powder recycling on the surface and selected technological properties of M300 maraging steel produced via the SLM method
(MDPI, 2024) Mechali, Abdesselam; Hlinka, Josef; Kresta, Michal; Petrovic, Marin; Měsíček, Jakub; Jahan, Ibrahim; Hajnyš, Jiří; Petrů, Jana
This study delves into selective laser melting (SLM). By using M300 steel in virgin and recycled powder form (after 20 cycles), with the aim of reducing the cost of printing for the practical application of M300 maraging steel, a comprehensive comparison between the two types of powder was evaluated. The powder's morphology was analyzed using scanning electron microscopy (SEM) and backscattered electrons (BSE). The particles were seen to have a spherical shape, with a notable number of satellites attached to their surfaces. The particle size distribution (PSD) was examined and ranged from 10 to 90 mu m for both powders. In addition, the porosity exhibited an average value of 0.07% for the virgin powder and 0.10% for the recycled powder. The microstructure was examined. Additionally, the surface wettability was tested, and it was seen to display wetting behavior for both types of powder, while blackened surfaces showed a higher wetting angle than untreated surfaces (hydrophobic). The 2D roughness measurements showed that the recycled powder had no significant difference from the virgin powder (Ra = 5.33 mu m, Rz = 24.17 mu m) before blackening and (Ra = 5.48 mu m, Rz = 24.07 mu m) after blackening. Corrosion tests proved that the recycled powder did not affect the corrosion properties of the material, while blackening caused partial surface corrosion in both types of samples, regardless of the used powder.
Investigation of factors affecting the sound absorption behaviour of 3D printed hexagonal prism lattice polyamide structures
(Springer Nature, 2024) Vašina, Martin; Měsíček, Jakub; Mánek, Martin; Ma, Quoc-Phu; Hajnyš, Jiří; Petrů, Jana
The aim of this work is to investigate the sound absorption properties of open-porous polyamide 12 (PA12) structures produced using Selective Laser Sintering (SLS) technology. The examined 3D-printed samples, fabricated with hexagonal prism lattice structures, featured varying thicknesses, cell sizes, and orientations. Additionally, some samples were produced with an outer shell to evaluate its impact on sound absorption. Experiments were conducted using the transfer function method with an acoustic impedance tube in the frequency range of 250 Hz and 6400 Hz. The results showed that the studied geometric factors significantly affected the sound absorption of the PA12 samples. In some cases, the hexagonal prism lattice structures demonstrated relatively high sound absorption properties. Thanks to their properties such as lower weight, recyclability, and resistance to moisture and chemicals, these structures become competitive with commonly used sound-insulating materials, making them promising candidates for sound absorption. Furthermore, numerical simulations using Ansys software confirmed that the sound absorption properties of the open-porous material structures generally increased with higher specific airflow resistance. The findings highlight the advantages of 3D printing technology in producing complex, highly customizable porous structures for noise reduction applications.
Investigation of the tool wear progression in parting technology
(Univerzita Jana Evangelisty Purkyně v Ústí nad Labem, 2024) Drbal, Martin; Kolomý, Štěpán; Sedlák, Josef; Zouhar, Jan; Vítek, Jiří
Parting-off stands as a fundamental method of turning, involving the cutting of the workpiece. The tool is most frequently a replaceable insert secured in a clamping bed. A pivotal set of observable metrics that ascertain the efficacy of a tool and its appropriateness for machining a specific material under defined cutting conditions is its durability. These durability parameters need to be determined for all new tools to ensure optimal performance and application in various machining scenarios. The primary objective of this research was analysis of the wear experienced by replaceable cutting inserts within the realm of parting technology. There were three distinct variants of replaceable cutting inserts. These cutting inserts were applied in the parting process, consecutively machining two materials: bearing steel 100Cr6 and stainless steel 316L. The study not only encompasses the description of the cutting test procedure but also involves the meticulous execution of measurements and the subsequent analysis of the data procured from experimental activities. In the final phase of study, additional analyses are outlined to uncover the factors contributing to variations in certain obtained results. Those analyses, such as material or tool coatings analysis, provides more information about interplay between replaceable cutting inserts and the specific materials subjected to parting processes.Parting-off stands as a fundamental method of turning, involving the cutting of the workpiece. The tool is most frequently a replaceable insert secured in a clamping bed. A pivotal set of observable metrics that ascertain the efficacy of a tool and its appropriateness for machining a specific material under defined cutting conditions is its durability. These durability parameters need to be determined for all new tools to ensure optimal performance and application in various machining scenarios. The primary objective of this research was analysis of the wear experienced by replaceable cutting inserts within the realm of parting technology. There were three distinct variants of replaceable cutting inserts. These cutting inserts were applied in the parting process, consecutively machining two materials: bearing steel 100Cr6 and stainless steel 316L. The study not only encompasses the description of the cutting test procedure but also involves the meticulous execution of measurements and the subsequent analysis of the data procured from experimental activities. In the final phase of study, additional analyses are outlined to uncover the factors contributing to variations in certain obtained results. Those analyses, such as material or tool coatings analysis, provides more information about interplay between replaceable cutting inserts and the specific materials subjected to parting processes.
Audio monitoring of bone cement disintegration in pulsating fluid jet surgery under laboratory conditions
(Elsevier, 2026) Schaller, Melanie; Hloch, Sergej; Nag, Akash; Klichová, Dagmar; Pude, Frank; Zeleňák, Michal; Janssen, Nick; Rosenhahn, Bodo
This study investigates a pulsating fluid jet as a precise, minimally invasive and cold technique for bone cement removal. We utilize the pulsating fluid jet device to remove bone cement from samples designed to mimic clinical conditions. The effectiveness of a novel in-house designed long nozzle was tested to enable minimally invasive procedures. Audio signal monitoring, complemented by our introduced novel data correlation algorithm S4D-Bio, was employed to address challenges like visibility obstruction from splashing. The experiments aim to evaluate the effectiveness of our novel in-house designed long nozzle for minimally invasive removal of bone cement using a pulsating fluid jet as well as the prediction accuracy of the erosion rate. Within our experiments, we generate a comprehensive dataset of erosion profiles and their equivalent audio signals and make it available open-source. The use of SSMs yields experimentally demonstrated precise control over the predictive erosion process with a prediction accuracy of 98.93%. The study also demonstrates, that the pulsating fluid jet device, coupled with advanced audio monitoring techniques, is a highly effective cyber-physical system for estimating erosion depth under controlled conditions. On the other hand, this study presents the first application of SSMs in pulsating fluidjet surgery technology, marking a significant novelty. This research introduces the components of a future system for minimally invasive, cold and adaptive bone cement removal in orthopedic applications.
Mechanical behaviour and energy absorption performance of modified anti-tri chiral novel auxetic structures through experimental and numerical analysis subjected to surrogate metamodeling
(Elsevier, 2026) Ercument, Dervis Baris; Elmoghazy, Yasser Hamed; Al Mahmoud, Zummurd; Safaei, Babak; Sahmani, Saeid; Petrů, Jana
Considering the advanced properties of meta-structures in absorbing energy and high crashworthiness performance, in this work three novel auxetic-lattice structures are proposed and developed based on anti-tri chiral structure by applying the element transformation approach. The novel auxetics were made of polylactic acid plus (PLA+) and additively manufactured by fused deposition modelling. The presented designs were numerically simulated considering elastic-plastic isotropic material properties, using C3D8R brick elements with secondorder accuracy and by implementing mesh size 0.6 mm based on sensitivity analysis through Abaqus/Explicit 2020. The results were further validated by experimental investigation under quasi-static condition subjected to compression load. In addition, a hybrid surrogate metamodel using random forest (RF) and multilayer perceptron (MLP) deep learning has been developed and validated against experimental results. All three novel structures demonstrated auxetic behaviour by achieving negative Poisson's ratio (NPR). The best auxetic characteristics were achieved by the first modified anti-tri chiral (MATC1) structure, with a considerable NPR of -0.42. Furthermore, the numerical simulation results aligned with experimental results and metamodeling prediction has been accomplished. Yet, slightly higher prediction performance was confirmed by RF model over MLP model.
Effect of particulate reinforcement on the aging behavior of aluminium metal matrix composites - A review
(Elsevier, 2026) Kumar, T. Satish; Shalini, S.; Petrů, Jana; Kalita, Kanak
Particulate-reinforced aluminium metal matrix composites (Al-MMCs) have gained renewed attention as promising candidates for aerospace and automotive applications owing to their unique combination of physical and mechanical properties, near-isotropic behavior and cost-effectiveness compared to monolithic alloys. Commercially available Al-MMCs often incorporated with various ceramic particulates, which enhance performance in a range of structural forms. This review examines the influence of particulate reinforcement on the aging behavior of age-hardenable aluminium alloys. The incorporation of ceramic particulates is shown to accelerate the aging kinetics of the matrix, leading to a higher peak hardness. Both increasing the weight fraction and reducing the particle size contribute to greater hardness increments and shorter times to reach peak aging. The underlying mechanisms, including heterogeneous nucleation of precipitates and enhanced dislocation density at particle-matrix interfaces, are discussed to provide a comprehensive understanding of how reinforcement parameters govern aging response in Al-MMCs.
High-temperature cyclic oxidation and microstructural behavior of CoMoCrSi-based composite coatings with Al2O3 and YSZ on T91 steel
(Elsevier, 2026) Shetty, Rakshith Kumar; Hebbale, Ajit M.; Chandramouli, T. V.; Ramesh, M. R.; Petrů, Jana
This investigation focuses on the cyclic oxidation behaviour and microstructural evolution of CobaltMolybdenum-Chromium-Silicon coatings reinforced with alumina and yttria stabilised zirconia (YSZ) deposited on T91 steel by the atmospheric plasma spraying method. Characterization of the as-sprayed coatings was done to provide a consistent base line for comparison of the intercoatings. Cyclic oxidation experiments at 800 degrees C for 50 oxidation cycles was carried out with surface and cross section analyses using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) for the evaluation of oxidation scale formation, element distribution and phase stability. After cyclic oxidation, XRD showed an appearance of stable oxide constituents, which demonstrates the formation of protective scales on the coating surfaces. In comparison with unreinforced and alumina reinforced coatings, the YSZ reinforced coating displayed comparatively superior oxidation behavior as reflected in the more stable oxidation and less degradation during cyclic exposure. SEM examination of oxidized surfaces showed that the ceramic additions helped to increase coating integrity, improve scale adherence and reduce oxygen penetration. These effects were amplified for the YSZ-containing coating, showing a good response for high temperature oxidation. Overall, the addition of ceramic reinforcements, especially of YSZ, improved the phase stability and oxidation resistance of the CoMoCrSi-based coatings, which supports the suitability of the coatings for demanding boiler environments.
Mechanical characteristics and failure analysis of AA6082/TiC/graphene hybrid composites
(IOP Publishing, 2026) Lal, Sohan; Mittal, Rashmi; Sharma, Neeraj; Čep, Robert; Kumar, Ajay
The main aim of the present research is to improve the tensile strength of lightweight aluminium alloy 6082, which makes it fit for many advanced engineering applications. Considerable efforts have been made to investigate the tensile characteristics, hardness, microstructural and fractography of AA6082/TiC/graphene composite developed at different reinforcements loadings varying from 1 wt.% to 6 wt. %. The reinforcements used in the current research are TiC and graphene. The aluminium matrix composite fabricated using nanosized particles by stir-casting route. The tensile strength increases with the increase of TiC and graphene particles in the AA6082 matrix up to certain limit i.e. 5 wt.%. Once the reinforcement increases beyond the point at which agglomeration of the particulates starts, the tensile strength and hardness of the developed composites decrease. The x-ray diffraction (XRD) and scanning electron microscopy (SEM) was used for the investigation of elements and morphology. The fractography of the developed composite depicts the morphology of the fractured tensile specimens. The elongated dimples, tear ridges and micro-voids are found during fractography. The failure of the hybrid composites changes from ductile fracture to cleavage failure.
Effect of reinforced weave patterns on the mechanical performance and wear resistance of wool-epoxy composites
(IOP Publishing, 2026) Jain, Akanksha; Bajpai, Pramendra Kumar; Čep, Robert; Kumar, Ajay; Rattan, Nav; Purohit, Abhilash
This work investigates the effects of fabric weave architecture on the mechanical and tribological properties of sheep wool/epoxy composites manufactured using the hand lay-up technique. Four different weave patterns, namely plain, twill, satin, and basket, were fabricated using a manual handloom and reinforced in an epoxy matrix. The mechanical, interfacial, and wear properties were characterized using tensile, flexural, impact, pull-out, and dry sliding wear tests according to ASTM specifications. Among all the architectures, the satin weave architecture showed the maximum tensile strength of 132.6 MPa, flexural strength, and yield strength due to its lower crimp and higher yarn alignment, which favoured better load transfer. On the other hand, twill architecture offered the best tribological characteristics, and the Taguchi L27 analysis evidenced that the sliding distance is the most dominating parameter that controlling the wear rate. The SEM images showed evidence of good fiber-matrix bonding in satin and twill composites, and the plain and basket architectures revealed higher fiber pull-out and brittle fractures. These observations establish that modifications in weaving architecture could help attain significantly improved stiffness, strength, and wear resistance, and thus wool-reinforced epoxy emerges as a bio-sustainable material for light-weight structural and tribological applications.
Effect of porous material and black coating on solar desalination for sustainable water harvesting: A thermo-exergo-economic and environmental analysis
(Springer Nature, 2025) Sharma, Naveen; Kumar, Ajay; Čep, Robert; Monika; Katiyar, Ajit
The aim of this research is to improve the amount of freshwater yield of a square base pyramidal solar still (SBPSS) using porous material with and without black coating for sustainable water harvesting. Seven separate cases, i.e., smooth basin (C-A1), an absorber plate with clay pots facing upward (C-A2), upward-downward (C-A3), downward (C-A4) and clay pots with black coating facing upward (C-A5), upward-downward (C-A6), downward (C-A7), were tested under the meteorological conditions of Andhra Pradesh (16.6834 degrees N, 80.3904 degrees E), India. To mitigate the impact of fluctuations in solar radiation, the tests were carried out specifically from 7:00 AM to 7:00 PM, focusing on days, especially, with clear sky. The influence of porous material and black coating on the performance of SBPSS is investigated from the viewpoints of thermo-exergo-economic parameters. By putting clay pots inside the basin, the freshwater yield increases up to 2.04 L/m2 for C-A4, while the yield enhances further by black coating (C-A7) to 2.38 L/m2. Findings revealed the overall daily thermal efficiencies for C-A7, C-A6, C-A4, C-A5, C-A3, C-A2, and C-A1 as 32.17%, 30.26%, 28.10%, 27.74%, 26.49%, 25.41%, and 17.00%, respectively. Additionally, the daily exergy values are 1.25%, 1.38%, 1.52%, 1.70%, 1.86%, 2.23%, and 2.78% for C-A1, C-A2, C-A3, C-A4, C-A5, C-A6, and C-A7. The optimal configuration was C-A7, exhibiting thermal and exergy efficiencies that surpassed C-A1 by 89.24% and 122.58%, respectively. Moreover, the daily productivity improved by 90.76%, accompanied by a cost reduction of 44.51%, and a reduction in payback period by 159 days. Among all, C-A5 achieves the highest CO2 mitigation at 7.06 tons/year, followed by C-A7 at 6.63 tons/year.
Multi-objective RIME algorithm-based techno economic analysis for security constraints load dispatch and power flow including uncertainties model of hybrid power systems
(Elsevier, 2024) Pandya, Sundaram B.; Kalita, Kanak; Jangir, Pradeep; Čep, Robert; Migdady, Hazem; Chohan, Jasgurpreet Singh; Abualigah, Laith; Mallik, Saurav
In recent times, the landscape of power systems has undergone significant evolution, particularly with the integration of diverse renewable energy sources (RESs). This advancement presents an invaluable opportunity to enhance energy efficiency in the modern power grid, primarily by bolstering the role of stochastic RESs. The challenge lies in the optimal power flow (OPF), a multifaceted and non-linear optimization challenge that grows more complex with the inclusion of stochastic RESs that aims to optimize the allocation of power system resources to minimize the operational cost while maintaining the stability and security of the system. Addressing this, the current study introduces an innovative optimization approach, the Multi-Objective RIME (MORIME) algorithm. Drawing inspiration from the physical phenomenon of rime-ice, called the RIME, the MORIME seeks to effectively tackle OPF issues. This algorithm enhances solution accuracy by smartly dividing with nondominated sorting and crowding distance mechanism. The proposed OPF model incorporates three types of RESs: solar photovoltaic, wind and small-scale hydropower units. While uncertainties in wind speed and solar irradiation are managed through Monte Carlo simulations, the small hydro unit is considered a constant power source. The efficacy of the MORIME algorithm is tested on IEEE 30 bus systems and results indicate that the MORIME method identifies the optimal solution for the multi-objective OPF problem while satisfying the power system constraints, thereby proving its effectiveness and superiority over MOWOA, MOGWO, MOALO, MOMRFO and MOAGDE in terms of Hyper Volume (HV) and reciprocal of Pareto Sets Proximity (1/PSP) metrices. The MORIME source code is available at: https://github.com/kanak02/MORIME
Many-objective grasshopper optimization algorithm (MaOGOA): A new many-objective optimization technique for solving engineering design problems
(Springer Nature, 2024) Kalita, Kanak; Jangir, Pradeep; Čep, Robert; Pandya, Sundaram B.; Abualigah, Laith
In metaheuristic multi-objective optimization, the term effectiveness is used to describe the performance of a metaheuristic algorithm in achieving two main goals-converging its solutions towards the Pareto front and ensuring these solutions are well-spread across the front. Achieving these objectives is particularly challenging in optimization problems with more than three objectives, known as many-objective optimization problems. Multi-objective algorithms often fall short in exerting adequate selection pressure towards the Pareto front in these scenarios and difficult to keep solutions evenly distributed, especially in cases with irregular Pareto fronts. In this study, the focus is on overcoming these challenges by developing an innovative and efficient a novel Many-Objective Grasshopper Optimisation Algorithm (MaOGOA). MaOGOA incorporates reference point, niche preserve and information feedback mechanism (IFM) for superior convergence and diversity. A comprehensive array of quality metrics is utilized to characterize the preferred attributes of Pareto Front approximations, focusing on convergence, uniformity and expansiveness diversity in terms of IGD, HV and RT metrics. It acknowledged that MaOGOA algorithm is efficient for many-objective optimization challenges. These findings confirm the approach effectiveness and competitive performance. The MaOGOA efficiency is thoroughly examined on WFG1-WFG9 benchmark problem with 5, 7 and 9 objectives and five real-world (RWMaOP1- RWMaOP5) problem, contrasting it with MaOSCA, MaOPSO, MOEA/DD, NSGA-III, KnEA, RvEA and GrEA algorithms. The findings demonstrate MaOGOA superior performance against these algorithms.
Experimental investigation on solidification cracking & intergranular corrosion of AISI 321 & AISI 316 L dissimilar weld on pulsed current gas tungsten arc welding (PCGTAW)
(Elsevier, 2024) Patil, Tejas; Bhosale, Ajit; Manikandan, S. G. K.; Jose, Bibin; Naidu, Mithul; Salunkhe, Sachin; Čep, Robert; Nasr, Emad Abouel
Dissimilar metal combinations are frequently employed in the power generation and nuclear industries. Where stainless steel piping systems are connected to pressure vessels made of low- alloy steel, the subsystems of liquid rocket engines also have different, dissimilar material combinations. Dissimilar welding plays a vital role in ensuring the integrity, performance, and reliability of components and structures operating in cryogenic environments, in this study, plates of AISI 316L and AISI 321, each 5 mm thick, were successfully joined using the pulsed current gas tungsten arc welding (PCGTAW) technique with optimized process parameters. These weld joints are mostly present in rocket engines subjected to a cryogenic environment. Due to the low temperature environment, the metallurgical properties of these joints change, which affects their mechanical properties. As it is a structural part, PCGTAW welding is most common method for joining this kind of material. In this work, Microstructural analysis of the weldment revealed a combination of vermicular, lacy, and acicular ferrite morphologies in the fusion zone at the root, mid, and crown locations. Furthermore, no solidification cracking was detected in the weldments based on the optical micrograph and SEM results. Intergranular corrosion (IGC) testing indicated the absence of a ditch structure, suggesting that the heat-affected zone (HAZ) on both sides of the weld joint was not being susceptible to sensitization. However, the HAZ of the AISI 316L side exhibited coarser grains compared to AISI 321. Analysis of tensile properties revealed a significant influence of the testing environment on the tensile strength of the dissimilar welded joints. At room temperature, the average ultimate tensile strength (UTS) was measured as 621 MPa. Remarkably, at cryogenic conditions, the average tensile properties significantly increased to 1319 MPa. Microhardness analysis showed the highest hardness associated with the AISI 321 side. The fusion zone exhibited a large deviation in the hardness profile (205 +/- 10 HV), with the highest average hardness observed in the middle part of the weld. However, the hot cracking behavior of the weld was investigated by using a suutula diagram at various locations of the weld. The investigation revealed that the Creq/Nieq eq /Ni eq ratio exceeded the critical threshold value, effectively diminishing the propensity for hot cracking in the fusion zone. Overall, these findings underscore the effectiveness of the PCGTAW technique in joining dissimilar materials, as well as the importance of microstructural and mechanical property evaluations, especially under extreme operating conditions such as cryogenic temperatures.
Many-objective ant lion optimizer (MaOALO): A new many-objective optimizer with its engineering applications
(Elsevier, 2024) Kalita, Kanak; Pandya, Sundaram B.; Čep, Robert; Jangir, Pradeep; Abualigah, Laith
Many-objective optimization (MaO) is an important aspect of engineering scenarios. In manyobjective optimization algorithms (MaOAs), a key challenge is to strike a balance between diversity and convergence. MaOAs employs various tactics to either enhance selection pressure for better convergence and/or implements additional measures for sustaining diversity. With increase in number of objectives, the process becomes more complex, mainly due to challenges in achieving convergence during population selection. This paper introduces a novel ManyObjective Ant Lion Optimizer (MaOALO), featuring the widely-popular ant lion optimizer algorithm. This method utilizes reference point, niche preserve and information feedback mechanism (IFM), to enhance the convergence and diversity of the population. Extensive experimental tests on five real-world (RWMaOP1- RWMaOP5) optimization problems and standard problem classes, including MaF1-MaF15 (for 5, 9 and 15 objectives), DTLZ1-DTLZ7 (for 8 objectives) has been carried out. It is shown that MaOALO is superior compared to ARMOEA, NSGA-III, MaOTLBO, RVEA, MaOABC-TA, DSAE, RL-RVEA and MaOEA-IH algorithms in terms of GD, IGD, SP, SD, HV and RT metrics. The MaOALO source code is available at: https://github.com/kanak02/MaOALO.
Exploring electrospun Nafion nanofibers: Bibliographic insights, emerging possibilities, and diverse applications
(AIP Publishing, 2024) Avvari, Venkata Dinesh, VENKATA DINESH; Sreekanth, P. S. Rama; Shanmugam, Raghavanantham; Salunkhe, Sachin; Čep, Robert; Nasr, Emad Abouel; Kimmer, D.
Over the past several decades, there has been a significant surge in interest regarding the use of organic-inorganic hybrid polymers and nanocomposite membranes. The reasons for this are improved attributes, reduced costs, and the additional stability the influence membrane provides. This Review outlines the various techniques and methodologies used to prepare Nafion and its composites, delineating the promising benefits of the electrospinning process. Electrospinning has emerged as a versatile and promising technique for fabricating nanofibers with unique properties and wide-ranging applications. This study explores the electrospinning of Nafion, a perfluorosulfonic acid polymer widely known for its exceptional proton conductivity and chemical stability, into nanofibrous structures, unlocking new possibilities yet unknown features of its inherent properties. The morphology and chemical structure of the resulting nanofibers is analyzed. A thorough bibliographic analysis of electrospun Nafion was presented using the PRISMA approach for methodically presenting the report. Network visualization of connected authors and categorizing application-specific publications are also discussed. Moreover, the electrospinning parameters and blends are systematically investigated to optimize the production of Nafion nanofibers for various applications in fuel cells, water treatment, actuators, sensors, and energy harvesting. The challenges involved in electrospinning Nafion, Nafion nanocomposites, and their variants are also presented, with a discussion delineating the future scope. This work concludes by emphasizing the interdisciplinary character of the Nafion polymer and its composites, connecting materials science and the intricate issues presented by various sectors.
Exploring fabrication strategies and innovative applications of ionic polymer metal composites: state-of-the-art review
(IOP Publishing, 2024) Sridhar, Yesaswi Ch; Avvari, Venkata Dinesh, VENKATA DINESH; Sahu, Santosh Kumar; Sreekanth, P. S. Rama; Barick, Aruna Kumar; Salunkhe, Sachin; Čep, Robert; Abouel Nasr, Emad
Various studies have been conducted to investigate the development of sustainable materials that possess the ability to respond to specific stimuli while preserving their original form. Electric energy is the most appealing way to stimulate Ionic Polymer Metal Composites (IPMC), allowing them to act as actuators and sensors. IPMCs are excellent alternatives despite challenging manufacturing conditions due to their good strain rates, quick responsive nature, high reliability, and mechanical compatibility. IPMC materials are highly sought after for their bio-inspired features. Researchers are developing IPMC materials that can act as thrusters, which entails establishing scientific and engineering groundwork and grasping operational principles. Nonetheless, a substantial understanding of the factors affecting their competence and persistence has been achieved through these efforts. Moreover, there is progress in developing effective processing techniques to fabricate IPMC. In this paper, IPMC mechanisms and respective fabrication techniques are reviewed in brief. Similarly, applications of the IPMCs in various fields are also discussed.
An experimental and modelling approach to proclaim sustainable machining using avocado oil-based nano-cutting fluids
(Springer Nature, 2025) Anebo, Abera Ayza; Chenrayan, Venkatesh; Shahapurkar, Kiran; Gebremaryam, Gezahgn; Petrů, Jana; Soudagar, Manzoore Elahi M.; Bhaviripudi, Vijayabhaskara Rao; Rajagopal, Rajakrishnan; Bashir, Muhammad Nasir
Higher-end science and technology facilitate the human community with a sophisticated life despite it curses by abundant pollution. The alarming demand for sustainability pressurizes the manufacturing sector to ensure sustainable manufacturing. Since Molybdenum di sulfide (MoS2) and avocado oil are known solid and liquid lubricants respectively, hence, it is a worthwhile attempt to implement the bio-based degradable avocado oil enriched with nano Molybdenum di sulfide (nMoS2) particles as a potential machining fluid for CNC-end milling. Different proportions of avocado oil and nMoS2 were used to synthesise four distinct machining fluids to assess the individual impact of avocado oil and nMoS2 particles. The emulsification and sonication were employed to synthesise the fluids. A hybrid Grey Relational Analysis (GRA) coupled with Principal Component Analysis (PCA) was followed to scrutiny the effect of novel machining fluid on machining objectives. The experimental results of physio-chemical properties revealed that avocado-rich 0.5% nMoS2 excels among others. The L16 orthogonal array experiments associated with statistical analysis explored the developed machining fluid (A6W4/0.5) that significantly impacts the machining objectives. The experimental results manifest that nearly 64.87% of surface roughness and 93.3% of tool wear have been reduced during machining in the presence of A6W4/0.5 fluid than A4W6/0.75. The improved performance of the novel machining fluid upholds its potential to replace conventional fluids and ensure green manufacturing.
MORKO: A multi-objective Runge-Kutta optimizer for multi-domain optimization problems
(Springer Nature, 2025) Kalita, Kanak; Jangir, Pradeep; Pandya, Sundaram B.; Alzahrani, Ahmed Ibrahim; Alblehai, Fahad; Abualigah, Laith; Ezugwu, Absalom E.
In the current landscape, there is a rapid increase in the creation of new algorithms designed for specialized problem scenarios. The performance of these algorithms in unfamiliar or practical settings often remains untested. This paper presents a new development, the multi-objective Runge-Kutta optimizer (MORKO), which is built upon the principles of elitist non-dominated sorting and crowding distance. The goal is to achieve superior efficiency, diversity, and robustness in solutions. MORKO effectiveness is further enhanced by incorporating various strategies that maintain a balance between diversity and execution efficiency. This approach not only directs the search toward optimal regions but also ensures that the process does not become stagnant. The efficiency of MORKO is compared against renowned algorithms like the multi-objective marine predicator algorithm (MOMPA), multi-objective gradient-based optimizer (MOGBO), multi-objective evolutionary algorithm based on decomposition (MOEA/D), and non-dominated sorting genetic algorithm (NSGA-II) on several test benchmarks such as ZDT, DTLZ, constraint (CONSTR, TNK, SRN, BNH, OSY and KITA) and real-world engineering design (brushless DC wheel motor, safety isolating transformer, helical spring, two-bar truss, welded beam, disk brake, tool spindle and cantilever beam) problems. We used unique, non-overlapping performance metrics for this comparison and suggested a fresh correlation analysis technique for exploration. The MORKO algorithm outcomes were rigorously tested and confirmed using the non-parametric statistical evaluations. The MORKO algorithm proves to excel in deriving comprehensive and varied solutions for many tests and practical challenges, owing to its multifaceted features. Looking ahead, MORKO has potential applications in complex engineering and management tasks.

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