Hydrogen (H2) is a clean energy carrier, yet selecting an economically and industrially viable production pathway remains challenging due to competing technical, economic, and environmental trade-offs. This study develops a structured multi-criteria decision-making (MCDM) framework to evaluate ten H2 production technologies using nine criteria relevant to industrial applicability, including cost, efficiency, operating conditions, and environmental performance. A hybrid approach integrating the Analytic Hierarchy Process (AHP) with the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) was used to generate technology rankings, which are subsequently validated through the Multi-Objective Optimization by Ratio Analysis (MOORA) method and sensitivity analysis. The results identify Steam Methane Reforming (SMR) as the most viable option under current techno-economic conditions, offering high H2 yield (74%) and low production cost ($0.75 kg-1 H2), despite its environmental impact. Plasma reforming and coal gasification emerge as competitive alternatives, whereas electrolysis exhibits low emissions but remains cost-intensive. Thermolysis and bio-based routes, including bio-photolysis, photocatalysis, and fermentation, show favorable environmental performance but are constrained by limited yield and scalability. The proposed framework provides a transparent and adaptable decision-support tool for comparing H2 production pathways under evolving industrial and sustainability priorities.

Effective management of bubble dynamics is critical for enhancing hydrogen production efficiency in water electrolysis. This work establishes a dual Marangoni mechanism, driven by the interplay between solutal and thermal Marangoni effects, as a principal regulator of bubble behavior. Through systematic variation of applied current and electrolyte concentration, we demonstrate how this mechanism dictates bubble growth, detachment, and the resulting electrochemical oscillations. Chronoamperometry coupled with high-speed optical imaging shows that bubble evolution produces periodic potential oscillations, with a persistent microbubble carpet underlying each detached main bubble. A characteristic V-shaped dependence of bubble growth period on applied current is identified, arising from the competition between solutal and thermal Marangoni effects, where the transition current shifts to higher values with increasing electrolyte concentration. Faraday-based quantification indicates that the majority of produced hydrogen is contained within the main bubbles. While hydrogen output rises with current, optimal efficiency demands a balance between overpotential and gas evolution. Higher electrolyte concentrations lower the overpotential but modestly reduce bubble-mediated gas output. Collectively, this study deepens the fundamental understanding of how bubble dynamics govern electrochemical performance, offering guidance for the rational design of high-efficiency hydrogen evolution systems.

This article discusses the role of various imaging modalities in diagnosing and managing surgical renal conditions in pediatric patients. It emphasizes the importance of tailored surgical interventions based on accurate imaging assessments. The cases presented cover a range of conditions, including pelvic-ureteric junction obstruction, vesicoureteric reflux, congenital renal anomalies, and postoperative management. The article underscores the pivotal role of various imaging modalities in diagnosing and managing a spectrum of surgical renal conditions in pediatric patients, providing valuable insights for clinical decision-making.

Over the last two decades, scholars are interested in microchannel due to its uniquely designed feature, and now, a variety of applications are coming under knowledge. Our current research is focused on microchannel exploration for use in producing hydrogen using steam reforming using the methanol process. In this study, the vapour quality and homogeneity of water and methanol are assessed in a serpentine microreactor with V-inlet ports using COMSOL Multiphysics. The concentration of individual species (water and methanol) and vapour quality are measured along microchannel arc length with different parameters (heat flux, mass flow rate, concentration of individual species). In microchannel, the water–methanol solution gets vaporized at 200 mm of arc length at 120 W/m2 heat flux (523 K); i.e. vapour quality is coming to be unity. The difference in concentration of both the species is towards zero when the mass flow rate is decreasing and also witnesses a high mass fraction of hydrogen at the low mass flow rate, and zero difference in the concentration of species becomes a witness of homogeneity. The effect of different concentrations is observed with different concentrations of individual species and found that the mixture in microchannel neutral solution is achieved when the concentration of species is decreasing.

Controlling bubble evolution on the electrodes of water-splitting cells or chemical reactors is crucial for achieving higher energy efficiencies in these devices. However, the evolution of dual bubbles on electrodes and their impact on electrolysis efficiency remain largely unexplored. This study combines high-speed imaging and electrochemical analysis to investigate the growth dynamics of two bubbles generated by dual platinum microelectrodes with different reaction kinetics, using an interelectrode distance of 800 mu m, while varying the electrolyte concentration and the cathodic potential. The evolution of dual bubbles reveals three distinct modes: Mode I (coalescence-driven detachment), Mode II (alternating coalescence and buoyancy-driven detachment), and Mode III (buoyancy-driven detachment), each associated with unique electrochemical signals. Although bubble coalescence in Mode I results in earlier detachment, the electrolytic efficiency at constant potential decreases by up to 31 % compared to that of a single electrode, at -6V and 0.6 M electrolyte concentration. This reduction is attributed to coalescence-induced premature detachment, which shortens the time from plateau to peak current, thereby lowering efficiency. In Mode III, the reaction rate is slower than with a single electrode, attributed to greater Marangoni forces in the two-electrode setup. Mode II, however, is influenced by both of the above factors.

Gas bubble formation and detachment during water electrolysis critically affect electrochemical performance, particularly at high current densities. Bubble dynamics at the electrode interface are strongly influenced by both current density and electrode geometry. These dynamics govern coalescence behavior and detachment efficiency, thereby influencing overall electrolytic efficiency. A deeper understanding of these mechanisms can enable the rational design of electrodes for improved bubble management and system performance. In this work, the evolution of oxygen bubbles on horizontal wire electrodes was investigated during acid electrolysis using synchronized high-speed imaging and electrochemical measurements. Bubble size distributions were quantified across current densities (0.05-1.0 A·cm-2) and electrode diameters (100-500 μm). Coalescence dynamics were analyzed through energy and force balance considerations, while electrode performance was evaluated via polarization curves. The findings show that increasing the current density or electrode diameter leads to the formation of larger and more polydisperse bubbles. Coalescence events were predominantly concentrated at the apex of the electrode. Three distinct coalescence-driven dynamics emerged: the coalescence-induced movement mode, the coalescence-induced detachment mode, and the coalescence-induced jumping mode, with each mode governed by bubble radius ratios. Smaller diameter electrodes exhibited higher overpotentials at elevated current densities, underscoring their performance limitations. The results establish correlations between bubble behavior and electrode dimensions, offering valuable insights for designing optimized electrodes that enhance electrolysis efficiency via bubble control.

Bubbles generated during electrochemical and photoelectrochemical water splitting critically influence efficiency through complex factors, including chemical reactions, species transport, mass transfer at the three-phase interface, and bubble coverage. A detailed understanding of the nucleation, growth, coalescence, and detachment of micro- and nanoscale bubbles is vital for advancing water splitting technologies. Surface-attached bubbles significantly reduce the electrocatalytically active area of electrodes, leading to increased surface overpotential at a given current density. Consequently, their effective removal is pivotal for optimizing the electrolysis process. However, the intricate interplay among single bubble evolution, mass transport, bubble coverage, and overpotential remain inadequately understood. This review explores the fundamental mechanisms underpinning bubble evolution, with an emphasis on the Marangoni effect and its influence on bubble dynamics. Furthermore, recent advancements in understanding individual bubbles on micro and nano-electrodes are highlighted, offering valuable insights into scale-dependent bubble behavior. These findings enrich our knowledge of gas-liquid interfacial phenomena and underscore their industrial significance, presenting opportunities to enhance water splitting performance through optimized bubble dynamics.

Advancements in microreactor technology emerge as a promising solution for low-cost hydrogen (H2) production, and there is significant progress being made towards developing microreactor technology for onboard H2 production. It is possible that fully matured microreactor technology for onboard H2 production will become available in the next decade. This review summarizes the key numerical findings in the advancements of research on H2 production by steam reforming in microreactors. Although numerous studies are being conducted on microreactors for different fuels, flow altering structures, and reaction parameters for steam reforming, they still lag in considering all parameters. This study aims to comprehend all performance influencing parameters, both structural and reaction, to better understand the selection of a microreactor. Based on the findings of this study, it is recommended to use methanol as the fuel and an optimal design that is easy to fabricate while also offering high performance. Since performance is influenced by numerous parameters, identifying the best conditions for the reaction and optimal structure can be achieved through the use of artificial intelligence (AI) techniques.

Enhancing the efficiency of hydrogen production by optimizing gas product transfer within water electrolysis systems is essential. Employing high-speed photography and electrochemical techniques, the entire process of single hydrogen bubble evolution on a Pt microelectrode surface was measured. Results reveal a notable reduction in both bubble detachment radius and growth time with decreasing absolute potential (from −7 to −3 V) and increasing reaction temperature (from 30 °C to 50 °C). Additionally, a comprehensive model estimating bubble coverage on the microelectrode is presented, incorporating bubble radius and current as key influencing factors. This enables an accurate evaluation of mass transfer coefficients during bubble evolution in the absence of forced flow. Furthermore, findings reveal the dominance of bubble-induced micro-convection as the primary mass-transfer mechanism for gas products at high current densities [O (105–106 A/m2)]. The results also indicate that the mass transfer coefficient increases during the inertia-controlled growth stage of bubbles and decreases during the stage controlled by chemical reactions.

To understand the relationship between electrolytic hydrogen bubble evolution and electric potential fluctuations, a synchronized measurement system, comprising a high-speed camera and an electrochemical workstation, was employed to analyze single hydrogen bubble evolution on a microelectrode and investigate the voltage-time characteristics of a typical hydrogen evolution reaction. The results show periodic potential fluctuations caused by the periodic evolution of single hydrogen bubbles. The overpotential fluctuation during single bubble evolution exhibits two stages: an initial increase (Stage I) followed by a decrease (Stage II). The duration of Stage I decreases with increasing applied current. Subsequently, a balance of known forces was developed to clarify the critical roles of the Marangoni effect and electric force in bubble detachment dynamics, enabling the prediction of bubble detachment size. Furthermore, it was observed that, during single bubble evolution, the overpotential shifts from activation dominance to ohmic dominance. The magnitude of ohmic overpotential correlates with the bubble diameter, whereas activation overpotential correlates with the bubble's contact diameter. This study contributes to the understanding of activation and ohmic overpotentials linked to bubble evolution in water electrolysis devices, thereby facilitating the development of more efficient multiphase electrochemical reactors.

This study aims to give the possible adoption of autonomous vehicles (AV)in Indian smart cities. The majority of accidents that occur in Indian cities are from metropolitan areas, and the primary cause is human error. The adaptation of AVs for transportation would undoubtedly reduce these numbers while also assisting in the transformation and further development of Indian smart cities. For the analysis, the demographic and economic profile of smart city Noida has been selected which is quite fit for the analysis. The Unified Theory of Acceptance and Use of Technology (UTAUT) is chosen as the most practical framework for measuring AV adoption by residents. The study also examines the AVs technology adaptation and UTAUT method in support of many aspects that should be considered for greater acceptance of AVs technology in Noida. According to the findings of the investigation, AV technology has a significant potential to aid in the development of Indian smart cities by lowering travel costs while also providing passengers with safety and comfort. The main finding of this research indicates that residents of the smart city are willing to adopt AV technology, with an overall adoption willingness reaching 83%. Notably, among the age group of 18 to 25, an impressive 89% display a strong willingness for the adoption of AV technology.

India is the world’s second-most populous country, with an ever-increasing energy need. Harnessing renewable energy is best suited for India in order to meet the country’s electricity demand while also achieving the country’s sustainability goals. The majority of India’s land receives sufficient incoming direct normal irradiation from the sun, making it suitable for the installation of solar power plants. One of the most difficult aspects of installing solar power plants is the huge amount of land required by PV solar panels. Because the area of the canal top is unused, installing PV on the canal top might be a viable solution to this land-use issue. The paper demonstrates the present state of power demand and fulfillment utilizing various energy sources. The different canal top solar power plant installations throughout nations, their workings, scope, and concerns about technological adaptation are discussed in this paper.

In this study, the influence of various factors: nanoparticle type (Al2O3, SiO2, and TiO2), concentration (0.05%, 0.1%, and 1%), and flow velocity (Re = 50, 100, and 200) on various forces (slip mechanism) act on nanoparticles is analyzed which can affect heat transport characteristics. The study reveals that the concentration is a more significant parameter for enhancement in Nusselt number compared to others. All nanoparticles have the same size of 50 nm and are spherical in shape. The variation in nanoparticle type results in change in density, thermal conductivity, specific heat, and viscosity of nanofluids. The variation in nanoparticle type influences the gravity, Brownian, Thermophoresis the most. On the other hand, the change in velocity of nanofluids influences the Drag, Thermophoresis, Shaffman Lift, Magnus force the most.

Heat exchangers with high thermal performance are required for industrial applications. Using heat transfer methodology in conjunction with simple design changes and assembly functions of heat exchangers could be an effective way to accomplish this. An experimental analysis was performed in this study to improve the heat transfer performance of a double pipe heat exchanger by implanting a flat strip spring turbulator (FST) within the heat exchanger's inner tube. The experimental investigation of the Double pipe heat exchanger in conjunction with three sets of FST turbulators (pitch: 15 cm, 10 cm, and 5 cm) for turbulent flow (Re 9000-38000) was carried out. The Nusselt number, friction factor ratio, and thermal performance factor of heat exchangers with FST at various pitches are found to be between 60 and 170, 1.44 and 1.76, and 0.94 and 1.06, respectively. The highest heat transfer achieved by using a flat spring turbulator is 20% for a pitch value of 5cm. In comparison to other sets of FST, a double pipe heat exchanger with FST pitch value of 10 cm has greater thermohydraulic performance. When compared to previous research, the experimental results obtained from this work at higher Reynolds numbers the friction factor are within a well-accepted range.

There is numerous research on the double tube heat exchanger, but advancements in technology and the costs associated with designs have necessitated the advancement in the design feature of heat exchangers having compactness and quick heat transfer capability. An attempt has been made in the designing and fabrication of a heat exchanger that allows heat to be transferred across three distinct fluids. An experimental setup is constructed with the ability to be assembled very quickly and is suited for a variety of analyses. This heat exchanger is made up of three tubes: an aluminium tube, a copper tube, and a GI tube, which are arranged at the innermost, intermediate, and outermost positions. The heat exchanger's performance is assessed for three distinct fluid stream configurations; (i) m Al=const, m Cu= m GI (variation) (ii) m GI= m Cu=const, m Al (variation) (iii) m Al≠ m Cu≠ m GI (variation). Experiments were carried out using counter flow fluid stream configurations with turbulence flow conditions of hot fluid to evaluate effectiveness of the heat exchanger for maximum heat extraction from hot fluid streams. Variations in the flow of the outermost fluid stream were discovered to have a substantial impact on heat exchanger performance.

CNT-based nanofluids have been shown to have the highest thermal conductivity when compared to other types of nanofluids. As a result, the CNT-based fluid is now regarded as a new generation of nanofluids, attracting researchers to investigate its thermophysical properties and potential applications in a variety of heat transfer applications. However, there is a disparity in the data for thermophysical properties, and different claims about its long-term stability have been made. This work attempted to comprehend a broader field of study on the thermophysical characteristics of CNT-based nanofluids, which could aid the scientific community in making further advances in the field of CNT-based nanofluids. The synthesis, characterization, and experimental findings on the thermal conductivity and viscosity of CNT-based nanofluids are all included in this paper. Numerous factors influencing thermal conductivity and viscosity are thoroughly discussed. Additionally, numerous models for predicting the thermal conductivity and viscosity of nanofluids based on CNTs are investigated. The current work suggests the use of ANN models that can account for many factors in setting the correlation for thermal conductivity and viscosity and are accurate in predicting results. Apart from thermophysical properties, the hazardous effect of CNT on human health and the contribution of different works in the CNT usage for improving the performance of a solar collector are summarized to provide insightful information on advancement in this field. The study recommends standardization in CNT nanofluid preparation and thermophysical property measurement to eliminate disparity in results.

The thermophysical properties of nanofluids are the key deciding parameters for their applicability in various applications. The present work deals with the experimental study and regression analysis on the density of three categorical nanofluids Al2O3/EG, CuO/EG, and CeO2/EG. The experiments were conducted on Anton Paar (SVM 3000) over different concentration samples of 0.2, 0.5, 0.8, 1, and 1.5 vol% and temperature of 20-80celcius. The experimental investigation reveals that the density of these nanofluids shows a linear variation over temperature and concentration. From this finding, a regression analysis has been conducted to set up the correlation for density with concentration and temperature. From regression analysis plane equation was found very suitable to fit over the experimental data sets. Four different equations for the individual categorical nanofluid have been developed which can predict the density very accurately. For this equation, there is no requirement of density data of particle and base fluid density to calculate the results for these equations. (c) 2021 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the 3rd International Conference on Futuristic Trends in Materials and Manufacturing.

The present research paper is focused on the fabrication process, reinforcements, and mechanical and tribological properties of the magnesium metal matrix composite. Since magnesium composite has a low density and high mechanical properties, high corrosion resistance, low thermal expansion coefficients relative to the traditional metals and alloys. It is used the modern type of composite which is used in aerospace and the automotive industries. The efficiency of magnesium composites depends on the reinforcement materials and the homogeneity of the matrix material. The present review paper is presented few literature reviews available on the mixture of reinforcements with trending and demanding matrix of magnesium. Magnesium metal matrix composite is used for better mechanical and wear/abrasion properties. The adding together of reinforcements such as SiC, B4C, Al2O3, metallic glass, etc. is one way to strengthen the mechanical, chemical, and wear properties of various Mg-based composite. When graphite is applied, the tensile and hardness properties decrease along with decreasing wear rate. Waste materials can be used for reinforcing such as rice husk, fly ash, etc. to decrease the manufacturing expenditure and increase the mechanical properties of the magnesium hybrid composite.