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The Archimedes Screw Turbine (AST) is an innovative type of hydroelectric power plant that can be particularly useful in locations with very low-head sites (less than 10 m head). Compared to alternative hydroelectric turbines like Pelton, Francis, and Kaplan, the AST can provide a clean renewable energy source that is safer for fish and other aquatic species. While the AST is not universally superior to these other turbine technologies, it can offer unique advantages in certain low-head applications. Unlike Pelton, Francis, and Kaplan turbines, which typically require greater maintenance, debris collection systems, and continuous design improvements, the AST can operate effectively with fewer of these supporting requirements. To explore the potential of the AST in low-head hydropower generation, the present study conducted a comparative analysis of the AST against Pelton, Francis, Kaplan, bulb, and Vortex turbines. A meta-analysis was performed to synthesize data from various theoretical, experimental, and numerical studies, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, ensuring a rigorous and comprehensive review. The findings demonstrate that the AST can be a viable and advantageous option for power generation in sites with head heights below 10 m, generating between 4 kW and 140 kW of power with flow rates of 1–6 m³/s and efficiencies ranging from 72 % to 94 %. Additionally, this study provides an easy and quick method, along with analytical equations, for estimating the design parameters needed to predict screw power output. However, the suitability of the AST versus other turbines is highly dependent on the specific site characteristics and requirements. The analysis provides insights into the performance, maintenance needs, and environmental impacts of the AST compared to conventional hydroelectric turbines. These insights can inform decision-making on appropriate turbine selection for low-head hydropower projects.

Irrigation is a crucial component of the agriculture industry. The gross domestic output of India is about 15 % derived from its farmers. Crop failure is common among farmers, primarily because of inadequate irrigation techniques and irregular power and water supplies. To begin with, a survey of farmers from various parts of India was undertaken in this regard, and the results indicated that most of them lacked an effective irrigation system. An inventive solar-powered irrigation system devised and deployed to address this problem includes an automated Internet of Things (IoT) system. This IoT system, which functions based on the moisture content of the soil, plays a crucial role in ensuring that the crops receive the right amount of water at the right time. Furthermore, the PV pumping system addresses irrigation issues in various Indian climate conditions, including composite, warm and humid, cold, moderate, hot, and dry. The locations chosen for these climate conditions are Jaisalmer in Rajasthan, Bangalore in Karnataka, Itanagar in Arunachal Pradesh, Patna in Bihar, and Amaravati in Andhra Pradesh. Performance ratios range from 0.514 to 0.739, system and pump efficiencies from 61 % to 88.80 %, and 57.10 %–58.60 %, respectively.

Predicting PV system electricity output is necessary for daily operational management and annual power system planning when integrating solar collector-based photovoltaic (PV) stations into micro grids. Tilting the panels at the ideal angle to maximize solar energy capture is necessary to maximize PV station production. This optimal tilt angle (OTA) must be predicted as it is a nonlinear function of the total solar radiation, diffuse solar radiation, and direct solar radiation. This research explores the use of feature selection-based artificial neural networks (ANN) with various machine learning algorithms to predict the OTA for PV systems at specific locations, aiming to maximize PV output in micro grids. The study identifies global solar radiation, diffuse solar radiation, clarity index, and global solar radiation on inclined surfaces as the most critical inputs for predicting OTA, while extraterrestrial radiation is deemed the least significant. Implementing the appropriate input variables significantly enhanced prediction accuracy from 38.59 % to 90.72 %. Among the neural networks evaluated, the Elman neural network demonstrated the greatest improvement.

Abstract This work discusses selecting optimal brake friction composite alternatives based on an integrated MABAC (multi-attributive border approximation area comparison) and AHP (analytic hierarchy process) approach. Therefore, non-asbestos automotive brake friction composites containing varying proportions of cement dust (50 to 0 wt%) and barium sulfate (0 to 50 wt%) were developed and tribo-evaluated on a Krauss machine following European regulations. Composite made up of 30 wt% cement dust and 20 wt% barium sulfate had the highest friction coefficient (0.361), lowest variability coefficient (0.598), and maximum recovery (123.27%). The composite with the least fading (15.36%) included 50 wt% cement dust, whereas the composite with the lowest wear (9.10 g) and the least frictional fluctuations (0.271) contained 50 wt% barium sulfate. By AHP, the friction coefficient (0.1989), fade (0.1696), recovery (0.1551), and wear (0.1412) were selected as the essential criteria in the performance assessment. Based on the MABAC ranking evaluation, the composite comprises 20 wt% barium sulfate and 30 wt% cement dust has the best tribological profile, whereas the composites of solely cement dust or barium sulfate have the poorest tribological profile. The acquired ranking results were confirmed using other decision-making models and subjected to sensitivity analysis to demonstrate their robustness.

The purpose of this research was to develop “green” materials by combining poly(lactic acid) (PLA) with two agricultural by-products, namely flax seed meal (FSM) and rapeseed straw (RSS). The natural fillers (0–20 wt.%) were mixed with PLA through extrusion and then injection molded into specimens. The samples were analyzed for their thermal, morphological, mechanical, and physical features and biodegradability. Thermal properties and crystallinity were analyzed using Differential Scanning Calorimetry (DSC), while the morphology was investigated by Scanning Electron Microscopy (SEM). Mechanical properties were characterized through tensile, flexural, and impact measurements, while surface hardness was evaluated by Shore D tests. Water absorption and biodegradability of the samples were also examined. DSC measurements revealed a nucleating effect of both bio-fillers. Based on the tensile tests, major improvement in stiffness was found with the biocomposites having up to ∼16 % higher Young's modulus than neat PLA (2.5 GPa). It came, however, at the cost of tensile strength, which decreased from 56 to 51 MPa even in the presence of the lowest amount (2.5 wt.%) of FSM. Loss in strength was due to the limited adhesion between the components, as also supported by SEM images. The hardness slightly (1–2 %) improved in the presence of even 2.5 wt.% bio-filler and it remained at that level at higher filler loading as well. Laboratory-scale composting revealed that both fillers facilitated biodegradation with FSM being superior. In the presence of 10–20 wt.% FSM, the rate of decomposition was found to be twice as fast compared to neat PLA.

The present study deals with the erosive wear behaviour of a zinc-aluminum (ZA) alloy and composite in the slurry medium. The effects of reinforcement of zirconium diboride (ZrB2) particles in ZA alloy, as well as the impingement angle and duration of erosion wear responses have been studied. The slurry composition was prepared with 1.5 L of water and 500 g silica of a size range of 350–450 μm. The erosion tests are performed at a speed of 600 rpm for varying durations (20–80 h) and impingement angles (30°–90°). The erosive wear responses of the samples have been analyzed in terms of distinct features of their micro constituents like ZrB2 and the material removal mechanism in a prescribed set of conditions. A significant decrease in composite erosion compared to ZA alloy has been observed. With increased duration, both alloy and composite show increased erosive wear. Obtained results revealed that the composite shows 60–80 % less erosive wear than ZA alloy on operating conditions. The optimum results in wear have been observed at 45° for alloy and 60° for composite. Investigating topographical aspects using scanning electron microscopy and atomic force microscopy revealed that ZrB2 reinforcements resulted in smoother topography and reduced erosive wear.

The research on work-life balance (WLB) published in journals with a Scopus index between 2011 and 2022 is carefully examined in this work. Our research attempts to clarify the evolution and trends in WLB research and the importance of publications that Scopus indexes. After analyzing 2717 research articles, we found that WLB publications have a significant annual growth rate of 14.71 %, which suggests that the trend continues to grow. Significant changes are seen, with 1888 papers produced between 2017 and 2022 highlighting a notable increase in interest in the field. With 1608 papers, social sciences account for the majority of WLB research. With 54 publications, Griffith University (Australia) is the most affiliated institution. With 30 papers, the “Economic and Social Research Council of the United Kingdom” became the primary source of financing. The most prolific author, with nine publications, is Lingard H. At the same time, co-citation analysis reveals 168 co-cited authors. The United States (USA), the United Kingdom (U.K.), and Australia (A.U.) are the top three producing nations. A thematic analysis reveals ten major WLB themes, from work stress to difficulties with human resource management. This study provides crucial insights for policymakers and leaders to address work-life balance issues effectively. Using tools like Gephi or CiteSpace, we could deepen our understanding through advanced analysis methods such as page rank and network visualization.

Air pollution in the environment is growing daily as a result of urbanization and population growth, which causes numerous health issues. Information about air quality and environmental health risks provided by air pollutant data is crucial for environmental management. The use of artificial neural network (ANN) approaches for predicting air pollutants is reviewed in this research. These methods are based on several forecast intervals, including hourly, daily, and monthly ones. This study shows that ANN techniques forecast air contaminants more precisely than traditional methods. It has been discovered that the input parameters and architecture-type algorithms used affect the accuracy of air pollutant prediction models. ANN is therefore more accurate and reliable than other empirical models because they can handle a wide range of input meteorological parameters. Finally, research gap of neural networks for air pollutant prediction is identified. The review may inspire researchers and to a certain extent promote the development of artificial intelligence in air pollutant prediction.

The aim of this study is to develop a method for selecting and ranking automotive brake friction composite materials made from agro-waste and natural fibers. This is achieved by using an integrated multi-criteria decision-making methodology. Consequently, six composite samples are produced by reinforcing rice husk, rice husk ash, and Grewia optiva fiber. These samples are then assessed for their frictional properties using a laboratory-scale brake tribometer, in accordance with the requirements outlined in SAE J2522 standard. The selection criteria are based on the analyzed tribological parameters, which include friction coefficients, wear, and friction fluctuations fade-recovery performances. The CRITIC (criteria importance through intercriteria correlation) method was used to determine the importance of criteria for performance evaluation. Based on CRITIC analysis, the average friction coefficient (0.1592), recovery-3 (0.1363), friction fluctuations (0.1347), and performance friction coefficient (0.1240) were identified as the key criteria. The use of MARCOS (measurement of alternatives and ranking according to compromise solution) for ranking assessment reveals that composite materials reinforced with rice husk ash exhibit the most favorable tribological characteristics. The validation of the ranking using different decision-making tools demonstrates the reliability and effectiveness of the proposed approach.

Abstract The importance of solar radiation for the body’s ability to synthesize Vitamin D3 is well documented, yet the precise amount of sun exposure required to avoid Vitamin D insufficiency is less clear. To address this knowledge gap, this study sought to utilize the sun in a suitable period at the optimum dose by utilizing numerical simulations to determine the amount of Vitamin D3 synthesis in the skin according to season, time of day, and geographical location in Turkey. The study was carried out in three stages; in the first stage, daily, monthly, and annual values were determined in cases where the solar zenith angle has the active UV-B wavelength. The second stage determined the level of Vitamin D that can be synthesized in all skin types at 25% solar radiation exposure. In the third stage, the sun exposure time required for 1000 International Units (IU) for all skin types was calculated. According to the analysis, the yearly period of active synthesis of D3 on Earth lasts from the beginning of March to the third week of October. During the day, it is between 10:00 and 16:00. For 1000 IU/day, the average annual estimated times (minutes) are 5.05 for Type I, 6.3 for Type II, 7.6 for Type III, 11.35 for Type IV, 15.15 for Type V, and 25.25 for Type VI. The results of this paper will impact awareness for academic-medical users.

Abstract Dissolved oxygen (DO) is an important parameter in assessing water quality. The reduction in DO concentration is the result of eutrophication, which degrades the quality of water. Aeration is the best way to enhance the DO concentration. In the current study, the aeration efficiency (E20) of various numbers of circular jets in an open channel was experimentally investigated for different channel angle of inclination (θ), discharge (Q), number of jets (Jn), Froude number (Fr), and hydraulic radius of each jet (HRJn). The statistical results show that jets from 8 to 64 significantly provide aeration in the open channel. The aeration efficiency and input parameters are modelled into a linear relationship. Additionally, utilizing WEKA software, three soft computing models for predicting aeration efficiency were created with Artificial Neural Network (ANN), M5P, and Random Forest (RF). Performance evaluation results and box plot have shown that ANN is the outperforming model with correlation coefficient (CC) = 0.9823, mean absolute error (MAE) = 0.0098, and root mean square error (RMSE) = 0.0123 during the testing stage. In order to assess the influence of different input factors on the E20 of jets, a sensitivity analysis was conducted using the most effective model, i.e., ANN. The sensitivity analysis results indicate that the angle of inclination is the most influential input variable in predicting E20, followed by discharge and the number of jets.

The use of distributed energy resources (DER) programs, which include separate renewable energy (RE) programs, has expanded in residential as well as commercial structures as an outcome of recent technological developments. The virtual power plant (VPP) may improve the security and reliability of an electricity grid's operations through including energy storage, changeable loads, and distributed energy resources (DER), among other characteristics. Consequently, a growing number of scholars tend to focus on VPP and providing recommendations for its improvement. In order to facilitate the incorporation of distributed generation into electricity distribution systems, cutting-edge management ideas for facilities have emerged in the last few years. As a result, it is now more crucial than ever to improve management abilities for the combining of dispersed energy output and consumption using various virtual power plants (VPPs). To increase operational profits, it's crucial to make use of their capacity to play a role in power markets. This work provides a classification scheme for, and an in-depth analysis of, recent studies that provide VPP models featuring interactions with various forms of electricity markets. The objective of this article is to find out which VPP strategy will yield the greatest possible return in each legislative scenario. These consist of the model's design, strategies for resolving complex mathematical problems, involvement in various marketplaces, and the application of the suggested models to real-world case studies. The research has been evaluated, and it has been concluded that contemporary models are more comprehensive and realistic. This article additionally elaborates on and emphasizes the VPP concept from other researchers' findings. Moreover, a number of prevalent VPP projects from throughout the globe are included. The VPP research also addresses some potential challenges and recommendations for prospective growth.

In recent years, evacuated tube solar water heaters (ETSWH) have become popular due to their efficiency and low maintenance based on trends in India's solar thermal market. Numerous studies have focused on improving system performance. In the scientific literature, there is a lack of information on the selection of appropriate fin material and the benefits associated with it. The thermal efficiency (ηt) of ETSWH is directly impacted by the choice of fin material. In this context, the goal of this study was to assess the impact of copper and aluminum using fin material as well as the inclination angle on ETSWH's ηt. The experiments are conducted for mass flow rate (mwt) varying from 2 to 5l/h. With a mwt of 2l/h, the highest outlet temperature of 55°C was recorded, while the highest ηt was found at 41.2°C with a mwt of 5l/h. At all mwt, copper fin is more efficient than aluminum fin due to their superior thermal conductivity. Among the considered inclination angles, at an inclination angle of 30°, the efficiency of ETSWH is found to be optimal. ETSWH with a copper fin attains (ηt = 58.57%), which is more significant than the case when the aluminum fin is used (ηt = 51.50%).

The primary issues in the Himalayan Rivers are sediment and cavitation degradation of the hydroelectric power turbine components. During the monsoon season, heavy material is transported by streams in hilly areas like the Himalayas through regular rainfalls, glacial and sub-glacial hydrological activity, and other factors. The severe erosion of hydraulic turbines caused by silt abrasion in these areas requires hydropower facilities to be regularly shut down for maintenance, affecting the plant's overall efficiency. This article provides an in-depth examination of the challenges that can lead to cavitation, silt erosion, and a decrease in the efficiency of various hydroelectric turbines, and it demands attention on the design, manufacture, operation, and maintenance of the turbines. This study's main objective is to critically evaluate earlier theoretical, experimental, and numerical evaluation-based studies (on cavitation and silt erosion) that are provided and addressed throughout the study. As a part of this study, various strategies for mitigating the effects of these problems and elongating the time that turbine may be utilized before they must be replaced have been provided.

The present investigation focuses on assessing the water quality of groundwater surrounding brick kilns in the Jammu district of Jammu and Kashmir (J&K). At 43 different brick kiln sites in both north and south regions of Jammu, concentrations of heavy metals were measured using established techniques. The elements zinc, copper, iron, lead, cadmium, nickel, and manganese were analyzed utilizing an Atomic Absorption Spectrophotometer (AAS). The pollution load index value was consistently below unity across all sites, suggesting an absence of pollution and making the water suitable for consumption. The average concentrations, listed in ascending order, were found to be 0.38 mg/L for copper, 0.31 mg/L for zinc, 0.01 mg/L for iron, and 0.09 mg/L for manganese. Notably, concentrations of lead, cadmium, and nickel were found below the detectable levels. Evaluation of contamination factors revealed the sequence Cu > Fe > Zn > Mn, while the geo accumulation index followed the sequence Cu > Fe > Mn > Zn. Comparison of these findings with the established standards of World Health Organization and Bureau of Indian Standards indicated that the recorded ranges were within permissible limits. The study's outcomes suggest that heavy metal emissions from brick kilns may not significantly impact the quality of groundwater. Elevated copper levels found near brick kilns were likely to result from plumbing materials in the study area. Iron and manganese in groundwater seems to have geo-genic origin and not emission-related. This research represents a foundational step in examining groundwater contamination by heavy metals specifically in the neighborhood of brick kilns in Jammu district. It contributes to the establishment of a comprehensive database and serves as a reference point for future studies. Additionally, the study recommends regular monitoring of groundwater to ensure the maintenance of drinking water quality.

Micro-electrical discharge machining (μEDM) is severely affected by tool wear and its process variants, which can lead to compromised precision and dimensional disruptions in micro-part production. Several attempts have been made to address this problem by suggesting offline and online (real-time) tool wear compensation strategies. Research efforts in this area have intensified over the last 20 years. However, most methods proposed were applicable only for a few work-tool combinations and in limited input process parametric settings. Instead of tool wear compensation, several research articles have focused on strategies to reduce the negative impact of tool wear on the quality of fabricated parts. The present study systematically reviews various investigations conducted in this area and aims to add cutting-edge compensation for tool wear to future inquiries. The articles reviewed here are explored in detail. Critical findings/innovations are classified into four categories: tool wear in μEDM, tool wear compensation techniques, and offline and online compensation methods.

Solar thermal air collectors are economically efficient for the purpose of heating air in specific applications. This research examines the efficiency of a solar thermal air collector called a jet impingement solar thermal air collector (JISTAC) that is fitted with discrete multi-arc-shaped ribs (DMASRs) utilizing soft computing techniques. Linear Regression (LR), M5P, Gaussian Process (GP), and Random Forest (RF) are used to predict the Nusselt number (Nu), friction factor (f), and thermohydraulic performance (ηthp) of JISTAC. DMASRs absorber plates with different relative rib height (0.025–0.047), relative discrete width (0.32–1.72), arc angle (35°–65°), relative discrete distance (0.27–0.86), and relative rib pitch (0.58–3.1) were used. The tests yielded 245 data sets, with 173 assigned for training and 72 for soft computing testing. The GP surpasses other models in performance owing to its minimum error and maximum correlation coefficient value. The GP model has a MAE of 0.0347, a RMSE of 0.0564, a RAE of 10.88%, a RRSE of 12.77%, and a CC value of 0.9920. Furthermore, it has a model efficiency of 99%, making it the most prominent among the other models. The results indicate that the GP model is quite precise in predicting the ηthp of JISTAC.

The typical solar flat plate collector relies on materials like rock wool for insulation to minimize heat loss. However, the use of such inorganic materials raises substantial concerns for both the industry and the environment. Therefore, it is crucial to decrease the reliance on these inorganic materials and instead adopt readily available biodegradable materials that pose no environmental risks to the system. The current research presents the usage of agricultural waste as insulating materials for S-FPC fabrication. The novelty of this current research work is the effective utilization of agriculture waste (rice husk, stubble fibre, coco-peat, and nitrile rubber) as an insulating material for the fabrication of S-FPC. Experiments were performed with insulating thicknesses of 50 mm and 70 mm. The optimum temperature was recorded to be 50–53 °C with an average thermal efficiency of 64–66 % by using rice husk as the insulating material at 70 mm thick.

Nature is still the main focus of scientific and technological research, particularly in nanotechnology and because of its remarkable properties; nanotechnology has acquired much interest in recent years. This review focuses on up-to-date overview of classification of nanoparticles, characterization, methods of preparation, characterization and application of nanoparticles. Initial section of the review gives insight on various techniques for the synthesis nanoparticles, encompassing both bottom-up and top-down approaches. Different methods for the synthesis of nanoparticles are discussed in details. Highlighting the importance of controlling shape, size, and composition to develop nanoparticles and enhance the properties of nanoparticles. These properties include enhanced surface area, unique optical, electronic, and magnetic characteristics, as well as improved mechanical properties. Understanding these attributes is essential for harnessing nanoparticles in different applications effectively. Broad spectrum of applications for nanoparticles is also discussed. Additionally, nanoparticles have found applications in catalysis, environmental remediation, and antimicrobial coatings, contributing to sustainable development and environmental protection. Overall, nanoparticles represent a progressive area of research with tremendous potential for innovation and societal impact. Our evaluation will serve as a solid reference, assisting the scientific community to comprehend the discussed topic better by showing the role of each technique in a comparable manner. As the field of nanoparticles is constantly evolving, this review incorporates the latest research, developments, and advancements up to the time of its publication. A comprehensive understanding of their properties, synthesis and applications is decisive for realizing the full potential of nanoparticles in various scientific and industrial domains.

The purpose of this work is to propose a decision-making algorithm to select the optimal composite material for thermally conductive but electrically insulating applications, such as microelectronic packaging heat sinks, diodes, and other electronic devices. In particular, an algorithm based on the criteria importance through inter-criteria correlation (CRITIC) and additive ratio assessment (ARAS) methods are used to evaluate several conflicting attributes. The evaluated samples were acrylonitrile butadiene styrene (ABS) composites filled with 0–30 vol% of boron nitride (BN) particles and prepared through melt compounding. The performance attributes considered through testing were heat conductivity, electrical resistivity, density, hardness, and tensile properties (Young's modulus, tensile strength, and elongation). As expected, the composite containing 30 vol% BN exhibited the highest heat conductivity, electrical resistivity, and Young's modulus. Meanwhile, unfilled ABS had the highest elongation at break, tensile strength, and lowest density. With respect to hardness, the 1 vol% BN-loaded composite proved to be superior. Therefore, the experimental data revealed a considerable compositional dependence with no obvious trend. The optimal composition was identified by adopting the CRITIC-ARAS multi-criteria decision-making algorithm, based on which the 30 vol% BN-containing composite was dominant among all the prepared samples. A validation through other decision-making techniques was performed to support the robustness of the proposed technique. Additionally, a sensitivity analysis was carried out on several weight exchange scenarios to see the stability of the ranking results.

There have been growing concerns over using non-renewable resources while manufacturing goods and related environmental laws worldwide. As part of efforts to reduce dependence on non-renewable resources, the uses of natural resources in brake friction materials are gaining prominence. Therefore, a natural fiber from the Himalayan region, Grewia Optiva, was used in the present study to develop a sustainable material for automotive braking applications. Brake friction composite materials were manufactured with various amounts (0, 2.5, 5, 7.5, and 10 wt%) of Grewia Optiva fiber. The composites were evaluated for physicochemical and mechanical characterization, tribological properties, and noise propensity. The friction performance remains comparable for all composites between 0.41 and 0.44, while a 9–13% reduction in the specific wear rate was obtained for the ≥7.5 wt% Grewia Optiva fiber added to the composites. Fade-recovery performance improved significantly with increasing fiber amount, while friction fluctuations remained the lowest for the composite with 7.5 wt% Grewia Optiva fiber content. At the same time, the minimal stick-slip power was associated with the composite having no Grewia Optiva fiber content. Therefore, a multiattribute decision-making technique was employed to evaluate the overall performance of all the composites suggesting 7.5 wt% Grewia Optiva fiber as the optimal content.

Automotive brake friction composites based on several combinations of barium sulphate and cement by-pass dust (CBPD) were manufactured and tribo behaviour is examined as per European regulations on a Krauss machine. The friction coefficient increased upon increasing the amount of CBPD from 0 to 30 wt% and then decreased above 30 wt% CBPD and below 20 wt% barium sulphate contents. Conversely, friction fluctuations and wear increased with decreasing barium sulphate and increasing CBPD contents. In particular, 20 wt% barium sulphate and 30 wt% CBPD filled composites showed the highest friction performance of 0.361, moderate friction stability of 0.76, highest recovery performance of 123.27%, and lowest friction variability of 0.60, whereas the composite with 50 wt% CBPD showed the highest fade resistance of 15.36%. The friction and wear analysis revealed that the fade and recovery response decide the overall frictional performance, whereas material integrity and fade response were the significant determinants of wear performance. The composites' worn surfaces were examined to investigate the associated wear mechanism at the braking interface.

The present trend of miniaturization in various electronic devices has caused higher heat generation per unit area. Dissipation of highly concentrated heat from these devices is essentially required to ensure their safe and prolonged use. Therefore, consistent efforts are made to upgrade the cooling technology to meet the current requirements. The microchannel heat sink (MCHS) has gained much attention due to its inherent property of a higher surface area-to-volume ratio. The thermo-hydraulic performance of MCHS has been further improved by several methods including active and passive techniques. In this work, a comprehensive review of the literature is presented to discuss the prominent design modifications done in the MCHS to enhance the heat dissipation capacity using single-phase fluid flow. It was commonly observed that heat transfer enhancement usually occurs at the cost of pressure drop penalty and other flow complications; therefore, relevant parameters have been discussed to evaluate the design’s efficacy.

Multi-criteria decision-making (MCDM) methods have been widely used among researchers to provide a trade-off solution between best and worst, considering conflicting criteria and sets of preferences. An efficient and systematic literature review of these methods is needed to maintain their application in distinctive domains. To this end, this paper presents a comprehensive and systematic literature survey on “multi-objective optimization by ratio analysis” (MOORA) method and its fuzzy extensions developed and discussed in recent years. This review includes articles categorized based on the publication name, publishing year, journal name, type of applications, and type of fuzzy extensions. In addition, this review will enhance the understanding of practitioners and decision-makers on the MOORA method, its development, fuzzy hybridization, different application areas, and future work. The study revealed that the MOORA technique was predominantly used with the TOPSIS approach, followed by the AHP and COPRAS methods. Furthermore, 76.28 % use single and hybridization approaches among all MOORA studies, while 23.72 % use MOORA in a fuzzy environment.

The main objective of this work is to review the capability of using waste marble dust (MD) particles as reinforcing materials in recycled polymeric composites to achieve environmentally friendly materials. In the present study, polymer composites were fabricated from recycled polyethylene terephthalate (rPET) and MD and then analyzed for their structural and thermal properties. Preparation of rPET-based composites containing 0–20 wt% MD was carried out through extrusion and injection molding. For their characterization Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA) were applied. The DSC analysis revealed a nucleating effect of MD on rPET, which was manifested in a higher crystallization temperature (196.7 °C ⇒ 204.4 °C); however, the marble particles were also found to hamper chain mobility, thereby decreasing the crystallinity ratio (23.7 % ⇒ 19.2 %) of rPET and altering its crystalline structure. According to the TGA measurements, a slight increase occurred in the thermal stability of rPET, its major decomposition temperature increased from 446 °C to 451 °C when 20 wt% MD was incorporated into it. DMA showed an improved stiffness in the entire investigated temperature range for MD-filled composites versus neat rPET. Additionally, several factors were derived from the DMA data, including the effectiveness factor, degree of entanglement, and reinforcing efficiency factor which all suggested a decent interaction between the components indicating a proper reinforcing ability of marble powder. However, above 5 wt% MD content the reinforcing efficiency deteriorated due to the agglomeration of filler particles, which was also supported by scanning electron microscopic images.

The growing global population increases the need for energy and food. As agricultural land is invaded by renewable energy projects, the area of land that can be cultivated is decreasing day by day. Agrivoltaics offers an alternative solution to this situation by combining agriculture and photovoltaics on the same land. This study investigates the feasibility of a possible 175 m2 Agrivoltaic system in Ankara Turkey (39.57° N-32.53° E). The study consists of three phases. In the first stage, the annual, monthly and seasonal optimum tilt angle for 39.57° N latitude was determined. In the second stage, eight different models were created for different tilt angles for PV panels of three different efficiencies in the agrivoltaic system to be installed. AC electrical energy and net profit ($) that can be produced with these models were calculated. In the third and final stage, the potential land equivalent ratio amount of seven agricultural cropscombined with eight different models was calculated. In the scenario created for the region, the highest yield increase is 11.2 % with M1 model (β = 31.33°)-Thinfilm, while the lowest yield loss is 33.2 % with M4 (β = 90.00°) Thinfilm. The highest generated electricity and net profit are AC-15674 (kW h) and 1286 ($) respectively. For the agricultural land determined to be grown in the system, the highest yielding agricultural product was kiwifruit with a value of 2.07 and the lowest yielding product was bokchoy with 0.25. This study can serve as a basic technical guidance for the establishment of Agrivoltaic plants with the highest efficiency in the Mediterranean climate and mid-latitude regions.

This study analyses the feasibility of utilizing waste slate particles as a strengthening component in affordable 3D-printed composite materials to address environmental issues associated with waste management. Composite filaments were created by incorporating waste slate particles (5 %, 10 %, and 15 % by weight) into an acrylonitrile butadiene styrene (ABS) matrix and subsequently evaluated for mechanical properties. A twin-screw extruder obtained the composite filaments, while test samples were produced using a 3D printer by fused deposition modelling. The developed composites have a gradual variation in evaluated properties, about an 8 % increment in hardness, and a 40 % increment in flexural and tensile modulus was noted on the inclusion of 15 wt% of waste slate particles in the ABS matrix. The composites filled with 10 wt% and 5 wt% waste slate particles exhibited the maximum flexural strength (65.24 MPa) and tensile strength (42.11 MPa), respectively. These values were 5 % and 8 % higher than those of unfilled ABS. Furthermore, it was shown that the ABS matrix saw a decrease in elongation and impact strength as the dosage of slate particles increased. The fractured surface morphology indicated that filament breaking, filler pullout, and the creation of voids between neighbouring layers were the primary causes of material failure. The dynamic mechanical analysis (DMA) results show the reinforcing effect of slate particles by an increase of storage modulus with 13 % at 35 °C for the composite with 10 wt% slate particles and 20 % for that with 15 wt% slate particles. DMA results analyzed the composite's adhesion factor, degree of entanglement, reinforcement efficiency factor, and effectiveness factor to clarify the reinforcing mechanism of slate particles. The study determines that the most effective utilization of waste slate particles in an ABS matrix is achieved by including 10 wt%. The results of this study enhance the concept of recycling waste slate powder and reveal the potential for their utilization in several industries, including the aerospace, automotive, healthcare, and architectural sectors of 3D printing.

Multi-faceted growth and progression of the healthy and economical society, depends upon access to clean and safe water. Rapidly over-growing population, increased in industrialization, urbanisation, and widespread practices in agricultural have all together been contributing to the production of more rapid wastewater discharge, which has not only polluted or contaminated the water but also have played a role in killing the aquatic life. One class of harmful water pollutants that is frequently found in the environment is heavy metals. Almost every transition metal has the ability to dissolve as ions in water. Heavy metals including Pb, Cd, Hg, As, Se and others can contaminate water supplies. Conventional methods for waste-water treatment have peculiar challenges including economic feasibility, energy consumption, environmental hazards, time spent, etc. To overcome these limitations, nanotechnology have been developed, which has its greater extent of application in water treatment area. Nanoparticles have a greater probability of removing heavy metals from wastewater treatment due to their effective surface characteristics and chemical activity. This review focuses on the numerous treatment procedures that have been developed recently and also been applied practically for eradication of heavy metals from waste-water of various industries.

In this work, multi-criteria decision-making (MCDM) techniques namely the weighted aggregated sum product assessment (WASPAS) method and the measuring attractiveness by a categorical based evaluation technique (MACBETH) are applied for predicting the optimum performance of a solar water heating system (SWHS) equipped with perforated delta-shaped obstacles. In total fifteen SWHS design alternatives based on the variation of pitch ratio (0.5, 1, 1.5, 2.0), angle of attack (15°, 30°, 45°), and Reynolds number (400, 800, 1200) were selected. The Nusselt number, friction factor, and thermohydraulic efficiency were fixed as the selection criteria in evaluating SWHS alternatives. By the entropy method, the importance of the identified criteria is quantified as weight, whereas the ranking of SWHS alternatives is determined by the WASPAS and MACBETH methods. The results show that the SWHS design alternative with a Reynolds number of 1200, pitch ratio of 1, and 45° angle of attack exhibits the optimal performance in selected criteria. Sensitivity analysis was used to demonstrate the robustness of the acquired ranking findings, which were further, validated using ten popular decision-making models.

Hybrid hydrokinetic turbine (HKT) performance can be maximized with the right design and flow characteristics, but they can only be determined through a methodical process. Specifically, a computational study of modified hybrid HKT has been conducted, considering the design factors (attachment angle; radius ratio) as well as the water flow speed. The computational analysis is performed on the different configurations of hybrid HKT under different flow parameters. The computational findings showed that these factors have an effect on the overall performance characteristics of hybrid cross-flow HKT. The hybrid HKT model performs optimally at a combination of parameters with attachment angle = 60°, v = 0 .5 m/s, radius ratio = 0.4, and TSR value = 0.9. It was also determined that compared to the models with a radius ratio of 0.2, 0.6, and 0.8, this hybrid HKT model is 40 %, 1.46 %, and 20.49 % more effective. The chaotic behaviour of flow across the rotor has also been visualized.

Influence of Bacillus Subtilis (B. Subtilis) bacteria on the strength characteristics of 100% recycled concrete aggregate (RCA), incorporating silica fume (SF) as a substitution of cement, has been investigated in this study. Two groups of mixes (A for w/c=0.3 and B for w/c=0.35) were prepared using two different cement contents in each (400 and 450 kg/m3). The cement was partially substituted by weight with 5%, 7.5%, and 10% SF, with a constant concentration of bacterial culture (105 cfu/ml). All specimens were tested after a curing period of 7, 28, and 90days. The best results were observed by replacing cement with 7.5% SF via all mixes, with the best mix being A/2. At 90 days, the compressive strength (CS) of concrete in mix A/2 increased from 29.62 to 33.64 MPa for 5% SF, from 29.62 to 37.3 MPa for 7.5% SF and from 29.62 to 34.04 MPa for 10% SF with the addition of B. Subtilis bacteria. Similarly, for splitting tensile strength (STS) at 90days, the strength increased from 2.73 to 3.24 MPa for 5% SF, from 2.73 to 3.35 MPa for 7.5% SF, from 2.73 to 3.26 MPa for 10% SF. Calcite precipitation upon addition of B. Subtilis bacteria is considered the reason for the improved CS and STS of concrete, and SEM and EDS analysis confirmed this. Thereby, the formation of new C-S-H products and CaCO3 crystals in voids made the concrete denser. Incorporation of B. subtilis led to a 12 ± 1.5% increase in CaCO3 formation in concrete’s mortar after 7days of curing compared to specimens without bacteria. Moreover, the effect of atomic Ca/Si and Al + Fe)/Ca ratios was studied, and the results showed that the highest CS and STS were associated with the values Ca/Si = 0.17 and Al + Fe)/C = 2.95. Meanwhile, it is noteworthy that according to the Indian specifications (IS-10262–2009), based on the strength of the concrete, the findings of this work fulfill the requirements of lean, ordinary grade, and standard grade concrete. An economic study of all mixes has also been carried out. Additionally, using response surface methodology, a regression equation was developed to accurately predict the CS and STS and validate the data in this experimental work with a minimum range of error.

This work aims to develop and validate a novel composite material for fused deposition additive manufacturing utilizing poly (lactic acid) (PLA) and discarded slate powder. The slate powder is mixed into PLA filaments at varying percentages (0%, 5%, 10%, and 15%) using a twin screw extruder. The resulting filaments are used in a 3D printer to print the test specimens. The tensile strength of the testing specimens is improved up to 5 wt% by incorporating slate powder. In contrast, the tensile modulus, hardness, and impact strength are raised with slate powder up to 15 wt% in PLA-based filament by 19.03%, 10.67%, and 31.63%, respectively. The maximum flexural strength and modulus values are 93.25 MPa and 4.15 GPa, respectively, achieved at 10 wt% slate powder content PLA matrix. Moreover, slate powder's presence significantly affects the composites' dynamic mechanical properties, such as storage, loss modulus, and damping factor. The composite's entanglement density, C-factor, adhesion efficiency, and reinforcing efficiency factor are investigated using dynamic mechanical properties and correlated with their structural integrity. Results show that 10 wt% slate powder in the PLA matrix is sufficient for their successful application.

The current trend of miniaturization in many electronic devices, like computer processors, high-speed servers, MEMS devices, etc., has shown augmented performance. Still, thermal management is a significant concern for them. The present work performed a numerical analysis on the microchannel heat sink's open micro prism pin fin configuration (MCHS). The influence of prism pin fin sides (3 to 9) has been studied for copper substrate and working fluid water (single phase fluid flow). Finite volume-based commercial code has been opted to perform the numerical simulations. The present configurations simulated different Reynolds numbers (50–300) under the heat flux of 500 kW/m2. Observation revealed that the four-side arrangements have the best performance due to prominent secondary flow leading to efficient fluid mixing, whereas three-side configurations have the worst performance. Further, an increase in pin fin sides from 5 to 9 has almost negligible variation in thermal and hydraulic characteristics because of similar fluid flow characteristics. The four-side micro prism pin fin configuration has been further analysed by varying the prism radius from 0.175 mm to 0.325 mm. It was observed that a prism radius between 0.250 mm and 0.275 mm led to optimum overall performance due to more stable secondary fluid flow.

The article reviews the difficulties and its redressal in fusion welding (especially the most used welding processes in the industry; gas metal arc (GMA) and gas tungsten arc (GTA) welding) of aluminium alloys. The more excellent thermal conductivity, solidification shrinkage, oxide formation, and thermal expansion coefficient cause more difficulties welding aluminium alloy than other materials. Welding parameters (such as welding current, welding voltage, shield gas flow rate, welding speed, torch location, etc.) have a complicated and non-linear relationship with the weld's quality and the joint's mechanical characteristics. Several techniques are suggested for improved weld quality and joint strength, including pulsing the current, post-weld heat treatment, proportional mixing of the shielding gases, speedy shielding gas injection, and many more. Due to various materials varied chemical and thermal characteristics, the GMA and GTA welding of dissimilar aluminium alloy exhibits more difficulties. To get around the challenges, adjusting the torch position and choosing a filler material that works with both aluminium alloys are practiced.

The present investigation recommends some major modifications for performance improvement in the conventional solar still (CSS). Five different configurations have been analysed viz: (1) still with no wick, (2) still with a wick at 15° (3) still with a wick at 30°, (4) still with a wick at 45°, and (5) blackened basin solar still (BBSS) with a wick at 30°. Experiments were conducted in March because of favourable climatic conditions. The flow rate of water passing through the basin and the wick was kept constant for all the configurations (0.2 gram/m2sec). Experiments were conducted to calculate the distillate yield and to carry out 5E analysis (energy, exergy, energy metrices, exergo-economic analysis, enviro-economic analysis). The results explore that the BBSS had the highest productivity of 4.372 kg/m2 among all configurations. However, the distillate yield obtained in CSS with 30° wick is quite close to the BBSS yield i.e., 4.25 kg/m2. Distillate yield obtained in the remaining case of CSS with 15°, 45° and without wick is about 3.802 kg/m2, 3.925 kg/m2, and 4.102 kg/m2, respectively. Energy output for modified CSS was observed to be highest for BBSS i.e., 2.31 kWh/day. The embodied energy was also found to be highest for BBSS i.e., 457.15 kWh with a minimum energy payback time (EPT) of 1.11 years. In addition, CO2 mitigated/year was found to be highest for the BBSS (energy basis -2.01 tones and exergy basis -0.25 tones) compared with the CSS (energy basis -1.88 tones and exergy basis -0.21 tones). The cost of distillate yield was found to be lowest for BBSS, which is found to be ₹ 1.38/L along with the payback period of 91 days.

Exergy analysis is an important thermodynamic approach to studying the system's actual output, considering all losses. The present study is an analytical approach to calculating the thermal and exergetic efficiencies of the parabolic trough receiver using MATLAB R2018a simulation software. These efficiencies are evaluated considering temperature rise characteristics and parametric design factors. The influence of the solar air heater's thermal and exergy analysis-based mathematical model on all design parameters is examined. The receiver tube has multiple twisted tape inserts with three varying parameters, i.e., twist ratio (y/w) = 3 to 5, perforation ratio (dp/w) = 0.05 to 0.25, and winglet ratio (d/w) = 0.1 to 0.3. The twisted tape with y/w, dp/w, and d/w having values 3, 0.1, and 0.05 perform better regarding energy and exergy with values 84.27% and 4.28%, respectively. This thorough examination can prove to be highly effective and advantageous in generating the design model for the specified twisted tape parameter value without requiring extensive investment in actual experimentation while also furnishing an evaluation of the performance of the solar air heater design.

In order to fabricate a hybrid green metal-matrix composite, the present study investigated the effects of reinforcing a farm waste, cow dung ash (CDA), with hard ceramic titanium diboride (TiB2) of varying weight percentage ratios (0, 7.5:2.5, 5:5, 2.5:7.5 ratio). The physicomechanical and tribological performance were examined and noted that the tensile strength, hardness, and impact energy of the hybrid composites were enhanced with the incorporation of CDA and TiB2 reinforcements. Increasing CDA in hybrid composite reduced the density up to 4.12% and maximum increment in hardness and tensile strength was up to 28% and 24% respectively. The tribology test was conducted on a pin-on-disc tribometer at room temperature with varying loads (10 N–50 N), sliding velocities (0.52 m/s to 2.62 m/s), and sliding distances (500 m–1700 m). The wear loss and friction property of Al6061 has improved with reinforcement's addition and was found to be minimum at 2.5:7.5 (CDA: TiB2) weight percentages. The hybrid composites microstructure and worn surface profile are also associated with the observed tribological outcomes. The obtained results indicated that the S3 hybrid composite showed the best physicomechanical and tribological properties.

In this research, a non-fragile synchronization of bidirectional association memory (BAM) delayed neural networks is taken into consideration. The controller gain fluctuation seems in a very random manner, that obeys sure Bernoulli distributed noise sequences. Delay dependent criteria are derived to confirm the asymptotic stability of the BAM delayed neural networks. The non-fragile controller are often obtained by determination a collection of linear matrix inequalities (LMIs). A simulation example is used to demonstrate the efficiency of the developed control.

Structural Integrity and its response to the subjected cutting forces during machining, plays a vital role in the performance and the life of the machine tool. The machine tool must meet the demands of the stiffness and easy maintenance; in absence of this the desired machining accuracy during cutting operation is not achieved. While at the same time the machine structure cannot be made heavy which increases the manufacturing cost. The use of stiffener plates is a solution to this problem. However, the selection of the appropriate locations of stiffener plates based on only designer’s design knowledge and experience may not lead to desired results. Hence, Structural analysis in conjunction with the structural optimization methods are employed for getting optimized structures. In this paper, experimental results obtained from the cutting force measuring machine which was manufactured for the experiment were used to analyse and optimize the structure of machine tool. The analysis and optimization were done with the help of Finite element methods technique (Optistruct solver) and modelling being done in Hypermesh. The optimized structure with stiffeners, led to the decrease in the maximum displacement thus increasing the stiffness of the machine structure while avoiding resonance.

Heat transfer in water with the help of solar energy is an effective way to harness renewable energy and reduce reliance on non-renewable sources of energy. The utilization of turbulent promoters is an efficient solution to ameliorate the performance of heat exchangers (HE). The current work summarizes the experimental and numerical behaviour of HE reported in the literature, including the thermal examinations of HT and fluid flow characteristics with various turbulent promoters and tube arrangements. This article reviews multiple studies in which different twisted tape (TT) geometry enhances the HT rate in various HE tubes. The current work also compares the thermal performance (η) of TT configurations in HE tubes using correlations developed by different investigators. Maximum heat transfer and minimum friction factor concerning fluid utilized in the system may also produce the optimal form for twisted tapes.

This research works with the optimal design of marble dust-filled polymer composites using a multi-criteria decision-making (MCDM) technique. Polylactic acid (PLA) and recycled polyethylene terephthalate (rPET)-based composites containing 0, 5, 10, and 20 wt% of marble dust were developed and evaluated for various physicomechanical and wear properties. The results showed that the incorporation of marble dust improved the modulus and hardness of both PLA and rPET. Moreover, a marginal improvement in flexural strength was noted while the tensile and impact strength of the matrices were deteriorating due to marble dust addition. The outcomes of wear analysis demonstrated an improvement in wear resistance up until 10 wt% filler reinforcement, after which the incidence of dust particles peeling off from the matrix was observed, thereby reducing its efficiency. The best tensile modulus of 3.23 GPa, flexural modulus of 4.39 GPa, and hardness of 83.95 Shore D were obtained for 20 wt% marble dust-filled PLA composites. The lowest density of 1.24 g/cc and the highest tensile strength of 57.94 MPa were recorded for neat PLA, while the highest impact strength of 30.94 kJ/m2 was recorded for neat rPET. The lowest wear of 0.01 g was obtained for the rPET containing 5 wt% marble dust content. The experimental results revealed that for the examined criteria, the order of composite preference is not the same. Therefore, the optimal composite was identified by adopting a preference selection index-based MCDM technique. The findings demonstrated that the 10 wt% marble dust-filled PLA composite appears to be the best solution with favorable physical, mechanical, and wear properties.

In the present study, waste of tasar silk fiber was used as reinforcement in the epoxy resin. Tasar silk fiber waste (TSFW) was pre-treated with NaOH coupling agent before reinforcing it with epoxy matrix. Treated and untreated TSFW-epoxy composites were made using the compression moulding technique. Composites were characterized for physical, mechanical and wear properties. Effect of NaOH coupling agent and fiber loading were examined on TSFW-epoxy composite. Comparatively, lower void fraction of 5.1% was obtained at 30% reinforcement of treated TSFW composite as compared to 5.8% as obtained for untreated TSFW composites. The tensile strength, flexural strength and impact strength were observed to be 68.47 MPa, 41.18 MPa, and 2.2 J for untreated TSFW where as these properties exhibites marginal increment of 70.86 MPa, 43.52 MPa and 2.35 J respectively. Hardness of composite experienced enhancement of 6% upon using treated TSFW. Overall, 10% reduction in specific wear was observed upon using treated TSFW as compared to untreated one. Scanning electron microscope (SEM) analysis suggested that the tensile specimen undergoes ductile fracture while flexural specimen failed in brittle manner. Fiber agglomeration and large deformation of tasar silk resulted in improved strength as observed in SEM analysis.

The present research work develops an evaluation method based on the hybrid entropy-simple additive weighting approach to select the best biocomposite material based on several potentially conflicting criteria. Poly(lactic acid) (PLA) biocomposites with varying proportions of wood waste (0, 2.5, 5, 7.5, and 10 by weight) was developed and evaluated for physical, mechanical, and sliding wear properties. The biocomposite containing 10 wt.% wood waste exhibited the lowest density (1.183 g/cm3) and highest modulus properties (tensile modulus = 2.97 GPa; compressive modulus = 3.46 GPa; and flexural modulus = 4.03 GPa). The bare PLA exhibited the highest strength properties (tensile strength = 57.96 MPa; compressive strength = 105.67 MPa; impact strength = 15.25 kJ/m2), whereas flexural strength (100.43 MPa) was the highest for 5 wt.% wood waste filled biocomposite. The wear of PLA decreased with 2.5 wt.% wood waste incorporated and increased with further addition of wood waste. The experimental results revealed a high compositional dependence with no discernible trend. As a result, prioritizing biocomposites' performance to choose the best from various biocomposite alternatives becomes tough. Therefore, a multi-criteria decision-making process based on a hybrid entropy-simple additive weighting approach was applied to find the optimal biocomposite by taking the experimental results as the selection criterion. The results show that the 2.5 wt.% wood waste added PLA biocomposite proved to be the best solution with optimal physical, mechanical, and wear properties. The validation with other decision-making models supports the robustness of the proposed approach in that the 2.5 wt.% wood waste added PLA biocomposite is the most dominating. This study contributes by providing preferences for the selection criteria and assessing the best alternative from the available PLA biocomposites.

With the growing energy needs, a conscious effort has been made to use non-conventional energy sources to generate clean energy efficiently. Solar energy has always been popular among humanity. Using solar energy in heating applications is one of the most prominent ways to extract solar power. Various developments have been made to augment solar water heating system (SWHS) performance. Each modified design of SWHS has its advantages and disadvantages. Broadly, solar water heaters are categorized into two types: Flat plate solar collectors (FPSCs) and evacuated tube solar collectors (ETSCs). Earlier studies show that evacuated tube SWHS are more efficient than flat plate SWHS. Extensive research is going on the design modification of evacuated tube SWHS to enhance their efficiency. Firstly, the present review article briefly introduced the numerous types of solar collectors and their range of operation. The current work reviews various techniques used for heat transfer enhancement in SWHS, their advantages, and the region of applications. The article concentrates on research involving the usage of energy storage medium, nanomaterials, reflecting surfaces, and hybrid techniques for performance augmentation of ETSCs.

Soft robotics is an emerging area of research due to its safe interaction with humans; it also has exciting applications, such as wearable soft medical devices for rehabilitation, prosthetics, etc. Soft robots require soft actuators for performing desired movements, including bending, expansion, contraction, and twisting. This work focuses on bending-type multi-chambered extra-soft actuators actuated by pneumatic pressure. The corrugated design of a multi-chambered soft pneumatic actuator (SPA) is analyzed experimentally to observe the radial, longitudinal, and lateral expansions of different chambers, i.e., ballooning of the chambers under the application of air pressure. From the experimental study, it is observed that the ballooning mainly occurs at the free end of the actuator in a cantilever-type boundary condition, which could not be demonstrated by the computational solution using the finite element analysis (FEA). Moreover, it is observed that the effect of ballooning also disturbs the constant curvature profile of SPA. Therefore, a chamber-reinforcement solution is provided for minimizing the ballooning and ensuring the uniform bending of a SPA.

The present study was designed to explore the applicability of dolomite dust (a waste from a dolomite quarry) as filler in polymer composites. Therefore, fixed carbon fiber reinforced vinyl ester composites with varying dolomite dust proportions (0, 5, 10 and 15 wt.%) are manufactured and subsequently evaluated for physicomechanical and sliding wear properties. Experimental results indicate that density, void content, impact energy, hardness, tensile modulus, and flexural modulus increase with dolomite content increase. On the other hand, a continuous decrease in tensile and flexural strength was observed with increased dolomite dust content. The sliding wear tests were performed using L16 orthogonal design, considering four parameters: dolomite dust, sliding distance, applied load, and sliding velocity according to the Taguchi method. It was found that dolomite dust was the most noteworthy parameter of wear rate, followed by applied load and sliding distance.

The present study describes the optimization of the spacer length parameter of perforated delta-shaped winglets (PDWs) imposed on the absorber plate of the solar air heater (SAH). An experimental set up is designed to analyze the influence of artificial roughness (AR) variation on the thermo-hydraulic performance of SAH. The variable parameter of the PDWs is the spacer length (Spdw) which varies from0 mm to 300 mm in steps of 100 mm. The impact of variation of Spdw on Nusselt number (Nupdw), friction factor (frpdw) and thermo-hydraulic performance (ηpdw) is investigated. The fixed parameters of the PDWs are relative roughness height of perforated delta-shaped winglets = 0.8, relative longitudinal length of the perforated delta-shaped winglet = 2, relative transversal length of the perforated delta-shaped winglet = 0.66 and angle of incidence = 90°. The Nupdw and frpdwof SAH provided with artificial roughened in the form of PDWs were improved by 5.17 and 4.52 times in comparison to SAH having smooth absorber plate. At the optimum value of spacer lengthSpdw = 0 mm and Re of 12000, ηpdw attains a maximum value of 3.14 (>1). The study reveals the effectiveness of perforated delta winglets in the heat transfer augmentation of SAH.

Carbon-reinforced nylon composite material (PA12CF20), i.e., polyamide, has been widely used in the automotive, medical, and electronics industries for fabricating functional parts, especially in gear manufacturing, due to its excellent wear property. The present work investigates the optimal parameters of the fused filament fabrication (FFF) 3D printing technique using PA12CF20 as feedstock to fabricate parts for enhancing the sliding wear performance. The test specimens are fabricated as per the American society for testing and materials (ASTM) G99 standard. The hybrid heuristic tool, i.e., genetic algorithm-adaptive neuro fuzzy inference system (GA-ANFIS), has been used to train, predict, and optimize the sliding wear performance of the fabricated parts using carbon reinforced polyamide composite material. The experimental runs have been performed on 30 combinations of input factors based on face centered central composite design (FCCCD) and further used for training and optimization for the hybrid GA-ANFIS approach. Scanning electron microscopy has been used to characterize the wear crack of the PA12CF20. It is observed that the optimal parameters retrieved using GA-ANFIS have increased the wear performance of PA12CF20 fabricated specimens, and the same has been validated experimentally. Further, a lathe machine spur gear was fabricated using optimal parameters of the FFF technique and checked the suitability for end-use applications.

This research aims to study the effect of objective and subjective weighting methods in multi-attribute decision-making (MADM) and then develop a systematic framework for selecting the best natural fiber-reinforced friction composite for automobile braking applications. Therefore, sixteen friction composites with varying weight amounts (5, 10, 15, and 20 wt%) of pineapple, ramie, hemp, and banana fibers were fabricated and evaluated for tribological properties. The experimental results, such as friction coefficient, fade-recovery performance, friction fluctuations, wear, friction stability, and variability aspects, were discussed and considered performance attributes for selecting optimal composition. The results indicated that the incorporation of varying amounts of natural fibers has different effects on the tribological properties, making it challenging to prioritize the performance of the composites to choose the best from the set of composite alternatives. Therefore, EDAS (evaluation based on the distance from the average solution) MADM approach has been applied to pick the best alternative from sixteen natural fiber-based brake friction composites. As an input to EDAS, different types of objective and subjective weighting methods were used to identify the importance of each attribute. These methods include the CRITIC (criteria importance through inter-criteria correlation), entropy, BWM (best-worst method), and AHP (analytic hierarchy process). The results show that the composite alternative with 5 wt% ramie fiber exhibits the optimal tribological properties. The sensitivity analysis and validation reveal the robustness of the results, demonstrating that the same alternative dominates in diverse MADM and weighting conditions.

In this present study, the hybrid criteria importance through inter-criteria correlation (CRITIC) and multiplicative exponent weighting (MEW) optimization approach is applied to the problem of selecting an optimal brake friction formulation that satisfies maximum performance requirements. Automotive brake friction composites containing 5, 10, 15, and 20 weight percentages of natural fibers (hemp, ramie, and pineapple) were developed. These composites analyzed for tribological properties using a Chase testing machine following IS-2742 Part-4 standard. The tribological results, such as friction-fade (%), friction coefficient, friction-recovery (%), friction fluctuations, friction-variability, friction-stability, and wear, are fixed as performance attributes to identify the most suitable friction formulation. The performance coefficient of friction (0.548) and friction-stability (0.93) remain highest for 5 wt.% pineapple fiber composites. Whereas the lowest wear (1.08 g) along with the least friction-recovery (107.54%) was exhibited by 5 wt.% hemp fiber composites. The highest friction-recovery (121.56%) corresponding to the lowest friction performance (0.501) was exhibited by 20 wt.% ramie fiber added composite. On the other hand, 5 wt.% ramie fiber added composite display lowest friction-fade (22.12%) with least friction-variability (0.330) and fluctuation (0.178). The experimental results are found to be strongly composition-dependent and without any pronounced trend. Consequently, it becomes difficult to prioritize the performance of formulations to choose the best among a set of composite formulations. Therefore, a multi-criteria decision-based optimization approach called CRITIC-MEW was applied; that suggests 5 wt.% ramie fiber added composite satisfies the maximum preset performance criteria.