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CSAM is a solid-state process for depositing metal or metal-based composite materials in which the fine particles of metal or composite material are accelerated to supersonic velocity, making successful bonding feasible due to the high-impact velocity and heavy plastic deformation, all without the melting of the feedstock material. This review examines the basic CSAM mechanism, including deposition dynamics, bonding mechanism, dynamic recrystallization, residual stress evolution, and post-spray heat treatments which affect microstructural and mechanical properties. Although controlled by a few key factors like particle velocity, strain rate, and temperature rise, the bonding efficiency itself refines the grains through dynamic recrystallization, hence improving coating strength and performance. The predominating compressive residual stresses that enhance fatigue resistance and mitigation strategies to improve coating durability by post-spray annealing and laser peening are discussed. This review, by providing an overview of material behavior, optimization techniques, and advanced modeling approaches, underlines the CSAM potential for high-performance applications in aerospace, biomedical industries, and machinery. It further underlines its importance for the advancement of manufacturing innovation and materials science.

The global demand for button mushrooms has surged in recent years, driven by their health benefits, creating a significant challenge for the mushroom industry in meeting this increasing demand. The increasing reliance on human labor, which is becoming unsustainable due to labor shortages and rising wage costs, highlights the urgent need for automated harvesting solutions. This review examines the integration of automated systems in button mushroom harvesting, delving into the key components such as robots, mechanisms, machine elements, programming, and algorithms. It offers a thorough analysis of the performance, design, operational mechanisms, and advantages and limitations of robotic systems, comparing the different methods employed in automated harvesting. This paper compares the performance of all the mushroom harvesters, including the commercially available ones with manual harvesting, and identifies their potential and limitations. The commercial harvesters are shown to pick 2000 mushrooms per hour on average, which is similar to how much a skilled worker picks at the same time. However, commercial automation harvesting has a relatively low success rate, high initial cost, high operating cost, and energy consumption, identifying areas for future research and challenges. This paper serves as a valuable resource for researchers and industry professionals striving to advance automated harvesting technology and improve its efficiency in meeting the rising demand for button mushrooms.

Button mushrooms (Agaricus bisporus) grow in multilayered Dutch shelves with limited space between two shelves. As an alternative to conventional hand-picking, automated harvesting in recent times has gained widespread popularity. However, automated harvesting of mushrooms faces critical challenges in the form of growing environment, limited spaces, picking forces, and efficiency. End effectors for picking button mushrooms are an integral part of the automated harvesting process. The end effectors developed so far are oversized, bulky, and slow and thus are unsuitable for commercial mushroom harvesting applications. This paper introduces a novel three-finger hybrid gripper with rigid and soft parts, specifically designed for harvesting button mushrooms in automated systems even on narrow shelves. It discusses the design, fabrication, force analysis, and picking performance of the gripper in detail for both individual and clustered mushrooms. The results indicate that the gripping force depends on mushroom density and size. The inclusion of textured soft pads on gripper fingertips performs better compared with plain soft pads by reducing force by up to 20% and improving picking time. The gripper achieved a 100% picking success rate for single-grown mushrooms and 64% for clusters, with reduced picking times compared with existing end effectors. However, harvesting clustered mushrooms led to increased damage, suggesting the need for future improvements.

Additive manufacturing (AM) or 3D printing is a digital manufacturing process and offers virtually limitless opportunities to develop structures/objects by tailoring material composition, processing conditions, and geometry technically at every point in an object. In this review, we present three different early adopted, however, widely used, polymer-based 3D printing processes; fused deposition modelling (FDM), selective laser sintering (SLS), and stereolithography (SLA) to create polymeric parts. The main aim of this review is to offer a comparative overview by correlating polymer material-process-properties for three different 3D printing techniques. Moreover, the advanced material-process requirements towards 4D printing via these print methods taking an example of magneto-active polymers is covered. Overall, this review highlights different aspects of these printing methods and serves as a guide to select a suitable print material and 3D print technique for the targeted polymeric material-based applications and also discusses the implementation practices towards 4D printing of polymer-based systems with a current state-of-the-art approach.

Cold spray additive manufacturing (CSAM) is a cutting-edge high-speed additive manufacturing process enabling the production of high-strength components without relying on traditional high-temperature methods. Unlike other techniques, CSAM produces oxide-free deposits and preserves the feedstock’s original characteristics without adversely affecting the substrate. This makes it ideal for industries requiring materials that maintain structural integrity. This paper explores strategies for improving material quality, focusing on nozzle design, particle size distribution, and fine-tuning of process parameters such as gas pressure, temperature, and spray distance. These factors are key to achieving efficient deposition and optimal bonding, which enhance the mechanical properties of the final products. Challenges in CSAM, including porosity control and achieving uniform coating thickness, are discussed, with solutions offered through the advancements in machine learning (ML). ML algorithms analyze extensive data to predict optimal process parameters, allowing for more precise control, reduced trial-and-error, and improved material usage. Advances in material strength, such as enhanced tensile strength and corrosion resistance, are also highlighted, making CSAM applicable to sectors like aerospace, defense, and automotive. The ability to produce high-performance, durable components positions CSAM as a promising additive-manufacturing technology. By addressing these innovations, this study offers insights into optimizing CSAM processes, guiding future research and industrial applications toward more efficient and high-performing manufacturing systems.

The urgent need to address global warming and the energy crisis, caused by dependence on fossil fuels, has led to enhanced research for sustainable energy sources. The adoption of renewable energy alternatives has been swift, but the intermittent nature of these sources makes consistent power production challenging. To address this, various techniques are used to store energy from renewable sources, which can then be used in a controlled manner to meet rising energy demands while reducing global CO2 emissions. This article analyzes the state of the art of energy storage technologies, focusing on their characteristics, classifications, applications, comparisons, and limitations. The study also includes recent research on new energy storage types, as well as significant advances and developments.

Casting is one of the oldest manufacturing processes that has been in use since 3400 BC. Over the years, casting technology has evolved tremendously and is one of the most integral parts of ancient history as well as a modern society. The world produced a total of 109.8 million tons of casting in the year 2017, which is a clear indicator of the massive capacity of this industry. Most of it in the current scenario is being used by the automotive industries. Despite being the biggest and the richest industry in the field of energy, hydropower has never been a major market for the casting industry. This might be because the hydropower components are mostly manufactured using other techniques such as machining and rolling. Nevertheless, studies have proven that casting can be used for the manufacturing of several components of the hydropower, especially hydro turbines. Casting technology comes with its own sets of advantages and limitations. This study presents an overview of the status of the casting technology and challenges, the proper optimization in casting that needs to be considered, and the latest technological advancements in this area. This paper aims to develop a theoretical foundation for show-casing the beneficiary, challenges, and possibility of manufacturing hydro turbines through casting technology.

Most of the hydro turbines in Nepalese power plants are imported from foreign industries. Findings from the studies have shown that up to 60% of the 13,000 MW capacity hydropower projects under the survey stage in Nepal would need Francis type of turbine with unit size below 5 MW. To meet the demand for turbines, Nepal has imported turbines worth US$ 5,616,072. The imported turbines from foreign industries could not address local problems of Nepalese hydropower. In Nepal, due to the sediment-laden condition of rivers alternative design and manufacturing techniques of turbines are necessary. To provide the new manufacturing techniques of Francis turbine in Nepal local casting process can be a solution because metal casting is a hereditary profession in Nepal since ancient periods till now. Large-sized bronze cast bells that are placed in Nepalese temples were manufactured in ancient times without a proper theoretical study on them. This paper discusses the materials testing of investment cast and sand cast brass materials of 14 kW Francis runner of Turbine Testing Lab (TTL) for exploring the possibilities of manufacturing Francis turbine. Tensile, Compressive and Charpy impact tests were performed base on ASTM standards and also the microscopic study was conducted at Kathmandu university laboratory. These testing results can be helpful for further studies on alternate turbine manufacturing processes as well.

Turbine having complex profiles has always been a challenge to the manufacturers. With possible errors while manufacturing and surface finishing, it is nearly impossible attaining the same profile of blades or buckets as suggested by the hydraulic design. Specifically in the case of Nepal the manufacturing of Francis turbine runners has been a challenge due to its complex profile and lack of state-of-the-art manufacturing facilities in the Nepalese metal manufacturing industries. Many attempts have been made in the past to manufacture these runners with the available resources. However, the developed turbines have been of smaller size and dimensions and the process used for fabrication have been limited to these small runners. So, for fabrication of the Francis turbine runners a new process has been developed. The process makes use of a rapid prototyping technique called additive manufacturing. The developed method has made the manufacturers easier to manufacture the runners of complex profiles and larger size. The steps from modifications of the cad model to 3D printing and workshop fabrication has been discussed in this paper.