Search Results (28)

This study examines the capabilities and optimisation of electrochemical jet machining (ECJM), a component of the electrochemical machining (ECM) production chain. A localised electrolyte jet helps remove material from selective areas; it is a suitable process for contoured parts and hard-to-machine material without inflicting thermal or mechanical stresses. In this regard, the study incorporates details of an experimental layout and variation in parameters in terms of voltage, electrolyte concentration, and jet velocity. The most striking findings indicate that the material removal rate and surface quality are susceptible to parameters such as applied voltage and stand-off distance, and electrolyte concentration and jet velocity (via electrolyte supply rate) fixed. Higher voltages and fixed electrolyte concentrations give higher removal rates, though this might impair the surface finish, thereby requiring a trade-off at best. These results provide insights into optimising process parameters for enhanced precision and efficiency in ECJM. Future research could focus on advanced electrolytes and improving scalability for industrial applications. Full article

Laser–electrochemical hybrid machining (LECM) is promising in the processing of thin-wall parts, which avoids problems such as the weak stiffness of structures and thermal defects. However, while most studies focus on precision machining via LECM, few investigate the potential of this technique in macro-area processing. In this paper, the synergistic effects on the coupling of thermal field and electrochemical field on bulk material removal mechanisms in the LECM of additively manufactured Ti6Al4V are comprehensively analyzed experimentally and theoretically. According to the experimental results, LECM improved the material removal rate (MRR) by up to 28.6% compared to ECM. The induction of the laser increases local heating, accelerating the temperature rise of the electrolyte, eventually promoting the electrochemical reaction. The hydrogen bubble flow promotes overall heat convection between the electrode and workpiece, which facilitates the removal of the facial precipitates and increases the efficiency of electrochemical dissolution. Higher voltages and laser powers promote the formation of hydrogen bubble flow; meanwhile, they also aggravate laser energy scattering, limiting the overall machining efficiency. Additionally, laser irradiation causes the ablation and rupture of hydrogen bubbles, which weakens the bubble flow effect and ultimately decreases the material removal efficiency. This study reveals the underlying mechanisms of the joint effects of the laser field and electrical field in LECM, and the findings can provide valuable insights for the optimization of LECM parameters in industrial applications. Full article

Amidst the global shift towards a low-carbon development trajectory, the hickory industry in Lin’an District is progressively embracing green, low-carbon, and sustainable practices. This study, leveraging the life cycle assessment (LCA) methodology, meticulously scrutinizes the carbon footprint of the hickory industry by segmenting its life cycle into two distinct subsystems: the plantation and the factory. Through comprehensive, year-long monitoring of soil greenhouse gas (GHG) emissions in hickory plantations, our findings underscore that while total GHG emissions from eco-complex management (ECM) surpassed those of intensive management (IM) by 10.7% (p < 0.001), ECM significantly mitigated the carbon footprint per kilogram of hickory produced, achieving a reduction of 1.0495 kgCO₂eq. This advantage is primarily attributable to ECM’s diminished reliance on chemical fertilizers. Within the factory subsystem, when processing 1 kg of hickory, the digital factory incurred a carbon footprint of 2.5923 kgCO₂eq kg⁻¹, whereas family workshops exhibited a lower footprint of 1.9544 kgCO₂eq kg⁻¹. Notably, the processing and packaging stages collectively accounted for over 90% of the factory subsystem’s carbon emissions, with natural gas being the primary contributor during processing. To estimate the carbon emission reduction potential within the hickory industry, this research draws parallels with emission reduction strategies employed by other industries and outlines tailored strategies to propel its low-carbon development. By advocating for the widespread adoption of ECM and enhancing the energy efficiency of processing enterprises, the hickory industry can effectively diminish its carbon footprint and steer towards a green, low-carbon, and high-quality development paradigm. Full article

The duck industry is vital for supplying high-quality protein, making research into the development of duck skeletal muscle critical for improving meat and egg production. In this study, we leveraged Oxford Nanopore Technologies (ONT) sequencing to perform full-length transcriptome sequencing of myoblasts harvested from the leg muscles of duck embryos at embryonic day 13 (E13), specifically examining both the proliferative (GM) and differentiation (DM) phases. Our analysis identified a total of 5797 novel transcripts along with 2332 long non-coding RNAs (lncRNAs), revealing substantial changes in gene expression linked to muscle development. We detected 3653 differentially expressed genes and 2246 instances of alternative splicing, with key genes involved in essential pathways, such as ECM–receptor interaction and Notch signaling, prominently featured. Additionally, we constructed a protein–protein interaction network that highlighted critical regulators—MYOM3, MYL2, MYL1, TNNI2, and ACTN2—associated with the processes of proliferation and differentiation in myoblasts. This extensive transcriptomic investigation not only sheds light on the intricate molecular mechanisms driving skeletal muscle development in ducks but also provides significant insights for future breeding strategies aimed at enhancing the efficiency of duck production. The results emphasize the efficacy of ONT sequencing in uncovering complex regulatory networks within avian species, ultimately contributing to progress in animal husbandry. Full article

Aircraft engine blades are produced through various techniques, one of which is precise electrochemical machining (ECM), commonly applied in the aerospace, automotive, and electromechanical industries. This method achieves machining accuracy ranging from 0.1 to 0.3 mm. However, components with complex shapes still require grinding and polishing. During the grinding of aircraft blades, achieving high precision and maintaining strict dimensional control are essential. This involves monitoring the thickness of the blade at key cross-sections, as well as the radii of the leading and trailing edges, chord lengths, twist angles, and more. The paper introduces a developed robotic blade grinding process featuring iterative laser measurement of geometric parameters. A custom measuring device with laser heads was designed, calibrated, and tested for repeatability. The measurement data were then used to determine the blade feed rate and machining path via a fuzzy logic decision system. The proposed method was validated on a series of PT6 aircraft engine blades in collaboration with Pratt and Whitney Rzeszów. Full article

Molybdenum is an important material in modern industry, widely used in extreme environments such as rocket engine nozzles and microelectrodes due to its high melting point, excellent mechanical properties, and thermal conductivity. However, as a difficult-to-machine metal, traditional machining methods struggle to achieve the desired microstructures in molybdenum. Electrochemical machining (ECM) offers unique advantages in manufacturing fine structures from hard-to-machine metals. Studies have shown that molybdenum exhibits a fast corrosion rate in alkaline or acidic solutions, posing significant environmental pressure. Therefore, this study investigates the electrochemical machining of molybdenum in neutral salt solutions to achieve high-precision microstructure fabrication. First, the polarization curves and electrochemical impedance spectroscopy (EIS) of molybdenum in NaNO3 solutions of varying concentrations were measured to determine its electrochemical reaction characteristics. The results demonstrate that molybdenum exhibits good electrochemical reactivity in NaNO3 solutions, leading to favorable surface erosion morphology. Subsequently, a mask electrochemical machining technique was employed to fabricate arrayed microstructures on the molybdenum surface. To minimize interference between factors, an orthogonal experiment was used to optimize the parameter combination, determining the optimal machining process parameters. Under these optimal conditions, an array of micro-groove structures was successfully fabricated with an average groove width of 110 μm, a depth-to-width ratio of 0.21, an aspect ratio of 9000, and a groove width error of less than 5 μm. Full article

Inconel 718’s exceptional strength and corrosion resistance make it a versatile superalloy widely adopted in diverse industries, attesting to its reliability. Electrochemical machining (ECM) further enhances its suitability for intricate part fabrication, ensuring complex shapes, dimensional accuracy, stress-free results, and minimal thermal damage. Thus, this research endeavors to conduct a novel investigation into the electrochemical machining (ECM) of the superalloy Inconel 718. The study focuses on unraveling the intricate influence of key input process parameters—namely, electrolytic concentration, tool feed rate, and voltage—on critical response variables such as surface roughness (SR), material removal rate (MRR), and radial overcut (RO) in the machining process. The powerful tool, response surface methodology (RSM), is used for understanding and optimizing complex systems by developing mathematical models that describe the relationships between input and response variables. Under a 95% confidence level, analysis of variance (ANOVA) suggests that electrolyte concentration, voltage, and tool feed rate are the most important factors influencing the response characteristics. Moreover, the incorporation of ANN modeling and the MOGA-ANN optimization algorithm introduces a novel and comprehensive approach to determining the optimal machining parameters. It considers multiple objectives simultaneously, considering the trade-offs between them, and provides a set of solutions that achieve the desired balance between MRR, SR, and RO. Confirmation experiments are carried out, and the absolute percentage errors between experimental and optimized values are assessed. The detailed surface topography and elemental mapping were performed using a scanning electron microscope (SEM). The nano/micro particles of Inconel 718 metal powder, obtained from ECM sludge/cakes, along with the released hydrogen byproducts, offer promising opportunities for recycling and various applications. These materials can be effectively utilized in powder metallurgy products, leading to enhanced cost efficiency. Full article

Deterministic polishing based on jet electrochemical machining (Jet-ECM) is a stress-free machining method for low-rigidity and ultra-precision workpieces. The nozzle is equivalent to a special tool in deterministic polishing, and the workpiece material is removed using the mechanism of electrochemical dissolution at the position where the nozzle passes. By precisely regulating the nozzle’s movement speed and dwell time, the quantity of material removed from the workpiece at a designated position can be finely adjusted. With this mechanism, the improvement of the workpiece shape accuracy can be achieved by planning the nozzle trajectory and nozzle movement speed. However, due to the positioning errors of the polishing device, the actual position of the nozzle may deviate from the theoretical position, resulting in errors in material removal amount, which affects the accuracy and stability of the polishing process. This study established a mathematical model to analyze the influence of nozzle positioning errors in deterministic polishing based on Jet-ECM. This model has been used to design a specific deterministic polishing device based on Jet-ECM. With the proposed deterministic polishing device, the surface shape of the workpiece is converged. The surface peak-to-valley (PV) value of the φ 50 mm workpiece (valid dimensions = 90% of the central region) indicated that the shape error of the surface was reduced from 2.67 μm to 1.24 μm in 34 min. The power spectral density (PSD) method was used to evaluate the height distribution and height characteristics of the workpiece surface. The results show that the low frequency spatial error is reduced significantly after processing. This study improves the accuracy of the stress-free deterministic polishing methods and further expands the use of deterministic polishing in industry. Full article

The present review was conducted to investigate the possibilities in realizing novel nanostructured tissues containing functional molecules that can be commercialized as solid products (without using emulsifiers and preservatives) for cosmeceutical and nutraceutical applications. After considering the principal concepts regarding skin and mucous features and physiologies, the possibilities in using bio-based, biodegradable and biocompatible materials was explored by investigating the correlations between their structures and morphologies with respect to the characteristics of the skin extracellular matrix (ECM). Regarding the new smart type of biodegradable tissues, their possible composition was reviewed in relation to the skin aging process and to the current contest for novel, innovative cosmeceuticals and nutraceuticals that consider the “beauty from within” concept. The barriers to the development of these new tissues were mainly identified due the necessity in defining the claim regarding green products. Moreover, the market growth data regarding these novel products were highlighted to support the idea that the diffusion of smart tissue-based cosmeceuticals and nutraceuticals is an opportunity for new sustainable industrial chains in the development of bioeconomies. Full article

Polymer–metal hybrid structures combine the merits of polymer and metal materials, making them widely applicable in fields such as aerospace and automotive industries. However, the main challenge lies in achieving efficient and strong connections between the metal and polymer components. This paper uses the jet electrochemical machining (Jet-ECM) method to customize the surface morphologies on 6061 aluminum alloy (AA6061) sheets. The connection between AA6061 and carbon fiber-reinforced PA66 (CF/PA66) is then achieved through hot pressure welding (HPW). The effects of aluminum alloy surface morphology, welding force, and welding time on the mechanical properties and microstructure of the joint are investigated. The optimal process parameters are determined by the design of the experiment. The results show that the aluminum alloy surface morphology has the greatest impact on the mechanical property of the welded joint. The optimal process parameters are surface morphology with wider, shallower, and sparsely distributed grooves on the aluminum alloy surface, the welding force is 720 N, the welding time is 12 s, the welding temperature is 360 °C, the cooling time is 16 s, and the optimal peak load of the joint is 6690 N. Under the optimal parameters, the fracture morphology in the AA6061 side is almost entirely covered with CF/PA66. The joint experiences cohesive failure in most areas and fiber-matrix debonding in a small area. Full article

Electrochemical machining (ECM) is widely applied to manufacture parts with complex geometries, used in electronic components and the automotive, military, and aeronautics industries. These parts have a surface shaped by controlled anodic dissolution at high current density levels, using a neutral solution of inorganic salts (i.e., NaCl or NaNO₃) as the electrolyte. Such conditions generate a high amount of sludge that deposits onto the surfaces of equipment, devices, cathodes, and working pieces, requiring daily and complicated sludge management during the series production in the industry. Thus, the main goal of the present work is to propose a simple way to reduce sludge generation in the ECM industrial process. To do so, complexing (EDTA) or reducing (ascorbic acid) agents were added to the electrolyte composition, creating parallel reactions to keep the metallic ions from precipitating. The complexing agent EDTA resulted in a 30% reduction in sludge mass, using an alkaline solution (pH > 10.0). The reducing agent, ascorbic acid, resulted in a 90% reduction in sludge mass, using an acidic solution (pH < 5.0). This sludge reduction has the potential to contribute significantly to increasing equipment, devices, and cathode lifetime, as well as reducing costs associated with centrifuge or filter maintenance (sludge removal from electrolyte) and increasing the productivity of industrial ECM processes. Full article

Despite its immense natural resources, Angola struggles to significantly improve its economy to reduce poverty. Carbon emissions have been increasing over the years, even though the country plans to reduce them by 35% by 2030. This paper attempts to assess the carbon emissions of several sectors (industries, transport, services, and residences) on economic growth, intending to find a balance between environmental protection that requires carbon emissions reduction and economic development that may add to environmental degradation. The study employed time series data on GDP, CO₂, CH₄, and N₂O covering 1971 to 2021 and ARDL and ECM models. This is the first study at the state level in Angola on the relationship between economic development and environmental sustainability considering methane and nitrous oxide emissions. Additionally, the paper assesses the responses of GDP to deviation shock of GDP, CO₂, CH₄, and N₂O by 2032. Phillip Perron and Augmented Dickey-Fuller tests showed that all the data are stationary at the first difference, favoring the application of the ARDL model to explore the short and long-run relationships. The result reveals that methane from agricultural activities and carbon emissions from the building sector and public services contribute to economic growth, whereas carbon emissions from industrial heat systems, non-renewable electricity production, and manufacturing industries harm economic growth. However, no relationship exists between nitrous oxide emissions and economic development. In addition, impulse response function estimates show that appropriate investments can sustain economic development over the years. Therefore, the country should diversify its economy and avoid polluting fuel sources, such as coal. Raising renewable energy’s proportion in the total energy mix can support growth while considering the environmental quality. Investments in skills training, academic projects in renewable energy technologies development, agriculture mechanization, and sustainable job creation are recommended. Additionally, investing in quality seeds adapted to climate realities might help lessen climate change’s adverse effects and promote growth. Manure manufacturing processes must be improved to reduce agriculture and livestock’s methane and nitrous oxide emissions. The country’s leaders are encouraged to promote raw material processing industries while insisting on reducing carbon emissions. Full article

Advancements and developments in the 3D bioprinting have been promising and have met the needs of organ transplantation. Current improvements in tissue engineering constructs have enhanced their applications in regenerative medicines and other medical fields. The synergistic effects of 3D bioprinting have brought technologies such as tissue engineering, microfluidics, integrated tissue organ printing, in vivo bioprinted tissue implants, artificial intelligence and machine learning approaches together. These have greatly impacted interventions in medical fields, such as medical implants, multi-organ-on-chip models, prosthetics, drug testing tissue constructs and much more. This technological leap has offered promising personalized solutions for patients with chronic diseases, and neurodegenerative disorders, and who have been in severe accidents. This review discussed the various standing printing methods, such as inkjet, extrusion, laser-assisted, digital light processing, and stereolithographic 3D bioprinter models, adopted for tissue constructs. Additionally, the properties of natural, synthetic, cell-laden, dECM-based, short peptides, nanocomposite and bioactive bioinks are briefly discussed. Sequels of several tissue-laden constructs such as skin, bone and cartilage, liver, kidney, smooth muscles, cardiac and neural tissues are briefly analyzed. Challenges, future perspectives and the impact of microfluidics in resolving the limitations in the field, along with 3D bioprinting, are discussed. Certainly, a technology gap still exists in the scaling up, industrialization and commercialization of this technology for the benefit of stakeholders. Full article

Cosmetic products contain preservatives to prevent microbial growth. The various types of preservatives present in skincare products applied on the skin induce many side effects. We tested several types of preservatives such as phenoxyethanol, methyl paraben, propyl paraben, imidazolidinyl urea (IU), the composition of gluconolactone and sodium benzoate (GSB), diazolidinyl urea (DU), and two grapefruit essential oils, one of which was industrially produced and a second which was freshly distilled from fresh grapefruit peels. This study aimed to find the relationship between preservative concentration, cell growth, collagen secretion, and cell viability. We hypothesized that these products induced a decrease in collagen secretion from human dermal fibroblasts. Our research, for the first time, addressed the overall effect of other preservatives on skin extracellular matrix (ECM) by studying their effect on metalloproteinase-2 (MMP-2) activity. Except for cytotoxicity and contact sensitivity tests, there are no studies of their effect on skin ECM in the available literature. These studies show potential antimicrobial activity, especially from the compounds IU and DU towards reference bacteria and the compounds methyl paraben and propyl paraben against reference fungi. The MTS test showed that fibroblasts are more sensitive to the tested group of preservatives than keratinocytes, which could be caused by the differences between the cells’ structures. The grapefruit oils exhibited the most cytotoxicity to both tested cell lines compared to all considered preservatives. The most destructive influence of preservatives on collagen synthesis was observed in the case of IU and DU. In this case, the homemade grapefruit oil turned out to be the mildest one. The results from a diverse group of preservatives show that whether they are natural or synthesized compounds, they require controlled use. Appropriate dosages and evaluation of preservative efficacy should not be the only aspects considered. The complex effect of preservatives on skin processes and cytotoxicity is an important topic for modern people. Full article

Most chronic inflammatory illnesses include fibrosis as a pathogenic characteristic. Extracellular matrix (ECM) components build up in excess to cause fibrosis or scarring. The fibrotic process finally results in organ malfunction and death if it is severely progressive. Fibrosis affects nearly all tissues of the body. The fibrosis process is associated with chronic inflammation, metabolic homeostasis, and transforming growth factor-β1 (TGF-β1) signaling, where the balance between the oxidant and antioxidant systems appears to be a key modulator in managing these processes. Virtually every organ system, including the lungs, heart, kidney, and liver, can be affected by fibrosis, which is characterized as an excessive accumulation of connective tissue components. Organ malfunction is frequently caused by fibrotic tissue remodeling, which is also frequently linked to high morbidity and mortality. Up to 45% of all fatalities in the industrialized world are caused by fibrosis, which can damage any organ. Long believed to be persistently progressing and irreversible, fibrosis has now been revealed to be a very dynamic process by preclinical models and clinical studies in a variety of organ systems. The pathways from tissue damage to inflammation, fibrosis, and/or malfunction are the main topics of this review. Furthermore, the fibrosis of different organs with their effects was discussed. Finally, we highlight many of the principal mechanisms of fibrosis. These pathways could be considered as promising targets for the development of potential therapies for a variety of important human diseases. Full article