Laser micro-nano processing technologies have been developed to address challenges that are otherwise difficult to solve in industrial applications and diverse scientific fields. These technologies offer designable patterning, arraying capabilities, three-dimensional (3D) processing, and high precision. Recent advancements in laser technologies have demonstrated their effectiveness as powerful tools for micro-nano processing of optoelectronic materials. By utilizing various laser techniques—such as laser-induced polymerization, laser ablation, laser-induced transfer, laser-directed assembly, and laser-assisted crystallization—broad applications in image sensors, displays, solar cells, lasers, anti-counterfeiting, and information encryption have been enabled. This review comprehensively summarizes recent progress in the laser micro-nano processing of optoelectronic materials, including the technologies used for preparation, patterning, arraying, and modification. These laser fabrication methods uniquely provide capabilities such as annealing, phase transitions, and ion exchange in optoelectronic materials. We also discuss the perspectives and challenges for future developments, including the advantages, disadvantages, and potential applications of different laser micro-nano processing technologies. With the rapid advancements in laser micro-nanofabrication, we foresee significant growth in advanced, high-performance optoelectronic applications. This review aims to provide researchers with insights into the current state and future prospects of laser-based micro-nano processing, encouraging further exploration and innovation in this promising field.
Materials of engineering and construction. Mechanics of materials, Industrial engineering. Management engineering
CrMnFeCoNi quinary complex concentrated alloys (CCAs) exhibit excellent mechanical properties due to the complexity of their atomic environment, attracting significant attention as potential structural materials. However, to effectively utilized CCAs in structural applications, a comprehensive understanding of their plasticity under various loading conditions is imperative for CCAs with various deformation mechanisms. In this study, quinary CCAs were systematically designed to exhibit constant yield strength by controlling the electronegativity difference and tailoring deformation mechanisms through the Gibbs energy difference between γ-austenite and ε-martensite. Uniaxial tensile tests and limit dome height tests were conducted to evaluate plasticity under both uniaxial and biaxial loading conditions. The normalized strain and displacement values revealed a significant reduction in plasticity for TRIP and TADP CCAs under biaxial loading. To elucidate this phenomenon, we compared the maximum Schmid factors of dislocation glide and martensitic transformation for random orientations. As a result, from a geometrical perspective, TRIP is not effectively activated under biaxial loading condition. These findings offer novel insights into the role of the Schmid factor in plasticity of CCAs, focusing on the critical impact of loading conditions on martensitic transformation. Consequently, our results establish effective guidelines for designing CCAs with enhanced plasticity under various stress states.
Materials of engineering and construction. Mechanics of materials
Adding appropriate amounts of Al and Cu atoms to high-entropy alloys （HEAs） can significantly improve mechanical properties of the alloys， but there are few research reports on the corrosion resistance of Al and Cu atoms in HEAs. To reveal the influence of Al and Cu atoms on the corrosion behavior of HEAs， this study focuses on FeCoNi based medium entropy alloys with excellent mechanical properties. FCC single-phase Fe25Co25Ni25Al10Cu15（Al10Cu15） alloy and BCC+FCC dual-phase Fe25Co25Ni25Al15Cu10（Al15Cu10） and Fe25Co25Ni25Al20Cu5（Al20Cu5） alloys are designed using empirical formulas for high-entropy alloy composition design. XRD analysis shows that the amount of FCC phase decreases and the amount of BCC increases with the increase of Al content， which is consistent with the theoretical calculation. SEM microstructure and EDS analysis show that increasing the amount of Al added and decreasing the amount of Cu added result in a transformation of the grain morphology from dendritic （Al10Cu15， Al15Cu10） to equiaxed （Al20Cu5）， and the composition of the interdendritic also changes significantly. The Al10Cu15 interdendritic microstructure is a Cu-rich FCC phase， the Al15Cu10 interdendritic microstructure is an Al-， Ni- and Cu-rich BCC phase， and the Al20Cu5 grain boundaries microstructure is a Fe- and Co-rich FCC phase. The potentiodynamic polarization（PDP） experiments show that alloys with high Al content have a dual-phase structure and are prone to galvanic corrosion during long-term immersion. The integrity of the passivation film is easily damaged， resulting in poor corrosion resistance of the alloy. The electrochemical impedance spectroscopy （EIS） tests show that the reaction resistance of alloys with higher Al additions decreases significantly with the prolongation of immersion time， which is consistent with the results of PDP analysis. Static immersion experiments at room temperature show that compared with Al10Cu15 alloy， Al15Cu10 and Al20Cu5 alloys are more susceptible to galvanic corrosion under prolonged immersion. It can be concluded that the addition of an excessive amount of Al atoms induced by the second phase significantly deteriorates the corrosion resistance of the material. Ensuring the homogeneity of alloy structure composition is an effective means to improve the corrosion resistance of materials.
Materials of engineering and construction. Mechanics of materials
Ultra-nanocrystalline diamond (UNCD) films were prepared by microwave plasma chemical vapour deposition (MPCVD) at different temperature conditions by adjusting the microwave power. The effects of the activation power of the reaction source and effects of the temperature of the substrate on the growth and composition of the UNCD films were compared and analysed in order to obtain the technique to rapidly grow high-quality UNCD films. SEM, XRD and Raman methods were used to characterise the morphological structure, phase composition and growth rate of the UNCD films, while OES spectroscopy was used to monitor the state of the growth groups during the deposition of the UNCD films. The results showed that the deposition temperature of the UNCD films ranged from 450 to 650 ℃; that the peak intensity of CN and C2 groups in the OES spectra increased with the increase of power and substrate temperature; that the growth rate increased from 0.82 μm/h to 6.62 μm/h; and that the grain size in the films increased. The average grain size was less than 10.00 nm, and the surface was flatter and smoother, forming a surface profile more favourable to the mechanical properties. Therefore, the use of diisopropylamine liquid small molecules as the reaction source, together with the application of higher microwave power and deposition at higher substrate temperatures, is an effective way to mushroom high-quality UNCD films.
Materials of engineering and construction. Mechanics of materials, Mechanical engineering and machinery
In order to tackle the problem of unbalanced distribution of educational resources in some regions, taking the real data of teachers and book resource allocation in 13 districts as example, an educational resource distribution model was proposed based on differential evolution (DE) algorithm, the effect of educational resource allocation model were compared and analyzed by simulation experiment. The results show that the model has similar allocation performance and the same time complexity, they can allocate educational resources reasonably and provide decision-making basis for education management departments, compared with the educational resource allocation model based on particle swarm (PSO) algorithm. However, with the increase of the amount of educational resources data, the model can obtain the optimal solution in fewer iterations, and the distribution result can effectively improve the problem of unbalanced distribution of educational resources. Finally, in order to verify the validity of the model, an educational resource allocation model based on artificial fish swarm algorithm is also proposed. The visualization of the distribution of educational resources data by three models is realized, which provides a certain theoretical basis for the statistics and distribution of educational resources.
Materials of engineering and construction. Mechanics of materials, Environmental engineering
Beatryz C. Mendes, Leonardo G. Pedroti, Carlos Maurício F. Vieira
et al.
Geopolymers are binder materials that can be an alternative to replace Portland cement. They are considered less aggressive to the environment because of the lower emission of CO2 and use of energy in their production chain. This work aimed to manufacture a more eco-efficient product and recycle industrial waste, contributing to the solution of the disposal problem. Thus, this study evaluated the performance of alkali-activated pastes produced from industrial wastes in both phases, using chamotte as the precursor and waste glass (WG) as a component of the activating solution. The effects of molar concentration and WG content in the alkaline solutions were investigated. A factorial design of experiments was developed, considering three levels of molar concentration (8 mol/L, 10 mol/L and 12 mol/L) and four levels of WG content per 100 mL of solution (0, 5, 10 and 15 g). Physical and mechanical tests were performed, as well as the microstructural analyses using XRD and FT-IR techniques. The environmental impacts of replacing the traditional activator by the WG-based one were also assessed. The results showed that the WG content strongly affects the mechanical strength of geopolymers and the quality of the matrices, promoting a greater formation of geopolymerization products. Using an alternative activator can reduce 69.8% of the embodied energy and 78.0% of CO2 footprint compared to the traditional waterglass activators. Therefore, this study proved the sustainability potential and technical viability of using WG as an activator in chamotte-based geopolymer.
Materials of engineering and construction. Mechanics of materials
Lower limb orthoses are used to assist gait, reduce pain, decrease weight bearing control movement, control movement and minimize progression of the deformity skills and assist ambulatory patients in achieving near-to-normal gait patterns in walking. Assistive devices can be advised with lower limb orthoses to help the patients ambulate more efficiently. Orthotic management should be specific to the disorders. The placement of orthotic joints should approximate anatomical joints. Most orthoses utilize a three-point force system to ensure proper positioning of the lower limb within the orthoses. Based on a comprehensive history and physical examination, a clear understanding of the patient’s disease process is the foundation for concluding an appropriate prescription. An effective prescription for orthotic treatment summarizes the medical issues related to the patients, details the biomechanical functions desired, and specifies critical technical attributes of the desired orthosis. No single material is a panacea, despite publicity for exotic materials. The selection of an appropriate material for a specific orthosis requires understanding the fundamental principles of engineering mechanics and materials, improving mechanical properties by heat treatment, and similar means, design, and structure. Sound clinical judgment, combined with consciousness fitting and adjustment of well-designed orthoses, remains the hallmark of orthotic treatment. International standards for terminology should be used to describe orthoses to ensure clarity and precision in prescriptions. Two auxiliary functions minimize the physical strain of walking: shock absorption and energy conservation. An optimum orthosis should be a replica of a mechanical system that can store these functions. This article overviews lower limb orthoses in classification, design, and construction and their biomechanical implications in usage in patients. Key words: Orthotics, Lower Limb Orthoses, orthosis, patients, functions, walking, prescription.
Achieving high detection accuracy of pavement cracks with complex textures under different lighting conditions is still challenging. In this context, an encoder-decoder network-based architecture named CrackResAttentionNet was proposed in this study, and the position attention module and channel attention module were connected after each encoder to summarize remote contextual information. The experiment results demonstrated that, compared with other popular models (ENet, ExFuse, FCN, LinkNet, SegNet, and UNet), for the public dataset, CrackResAttentionNet with BCE loss function and PRelu activation function achieved the best performance in terms of precision (89.40), mean IoU (71.51), recall (81.09), and F1 (85.04). Meanwhile, for a self-developed dataset (Yantai dataset), CrackResAttentionNet with BCE loss function and PRelu activation function also had better performance in terms of precision (96.17), mean IoU (83.69), recall (93.44), and F1 (94.79). In particular, for the public dataset, the precision of BCE loss and PRelu activation function was improved by 3.21. For the Yantai dataset, the results indicated that the precision was improved by 0.99, the mean IoU was increased by 0.74, the recall was increased by 1.1, and the F1 for BCE loss and PRelu activation function was increased by 1.24.
Materials of engineering and construction. Mechanics of materials
In the new issue, our scientific journal offers you thirteen scientific articles. As always, we try to offer a wide variety of topics and areas and follow current trends in the history of science and technology. In the article by Olha Chumachenko, оn the basis of a wide base of sources, the article highlights and analyzes the development of research work of aircraft engine companies in Zaporizhzhia during the 1970s. The existence of a single system of functioning of the Zaporizhzhia production association “Motorobudivnyk” (now the Public Joint Stock Company “Motor Sich”) and the Zaporizhzhia Machine-Building Design Bureau “Progress” (now the State Enterprise “Ivchenko – Progress”) has been taken into account. Leonid Griffen and Nadiia Ryzheva present their vision of the essence of technology as a socio-historical phenomenon. The article reveals the authors' vision of the essence of the technology as a sociohistorical phenomenon. It is based on the idea that technology is not only a set of technical devices but a segment of the general system – a society – located between a social medium and its natural surroundings in the form of a peculiar social technosphere, which simultaneously separates and connects them. Definitely the article by Denis Kislov, which examines the period from the end of the XVII century to the beginning of the XIX century, is also of interest, when on the basis of deep philosophical concepts, a new vision of the development of statehood and human values raised. At this time, a certain re-thinking of the management and communication ideas of Antiquity and the Renaissance took place, which outlined the main promising trends in the statehood evolution, which to one degree or another were embodied in practice in the 19th and 20th centuries. A systematic approach and a comparative analysis of the causes and consequences of those years’ achievements for the present and the immediate future of the 21st century served as the methodological basis for a comprehensive review of the studies of that period. The article by Serhii Paliienko is devoted to an exploration of archaeological theory issues at the Institute of archaeology AS UkrSSR in the 1960s. This period is one of the worst studied in the history of Soviet archaeology. But it was the time when in the USSR archaeological researches reached the summit, quantitative methods and methods of natural sciences were applied and interest in theoretical issues had grown in archaeology. Now there are a lot of publications dedicated to theoretical discussions between archaeologists from Leningrad but the same researches about Kyiv scholars are still unknown The legacy of St. Luke in medical science, authors from Greece - this study aims to highlight key elements of the life of Valentyn Feliksovych Voino-Yasenetskyi and his scientific contribution to medicine. Among the scientists of European greatness, who at the turn of the XIX and XX centuries showed interest to the folklore of Galicia (Halychyna) and Galician Ukrainians, contributed to their national and cultural revival, one of the leading places is occupied by the outstanding Ukrainian scientist Ivan Verkhratskyi. He was both naturalist and philologist, as well as folklorist and ethnographer, organizer of scientific work, publisher and popularizer of Ukrainian literature, translator, publicist and famous public figure. I. H. Verkhratskyi was also an outstanding researcher of plants and animals of Eastern Galicia, a connoisseur of insects, especially butterflies, the author of the first school textbooks on natural science written in Ukrainian. A new emerging field that has seen the application of the drone technology is the healthcare sector. Over the years, the health sector has increasingly relied on the device for timely transportation of essential articles across the globe. Since its introduction in health, scholars have attempted to address the impact of drones on healthcare across Africa and the world at large. Among other things, it has been reported by scholars that the device has the ability to overcome the menace of weather constraints, inadequate personnel and inaccessible roads within the healthcare sector. This notwithstanding, data on drones and drone application in Ghana and her healthcare sector in particular appears to be little within the drone literature. Also, little attempt has been made by scholars to highlight the use of drones in African countries. By using a narrative review approach, the current study attempts to address the gap above. By this approach, a thorough literature search was performed to locate and assess scientific materials involving the application of drones in the military field and in the medical systems of Africans and Ghanaians in particular. The paper by Artemii Bernatskyi and Vladyslav Khaskin is devoted to the analysis of the history of the laser creation as one of the greatest technical inventions of the 20th century. This paper focuses on establishing a relation between the periodization of the stages of creation and implementation of certain types of lasers, with their influence on the invention of certain types of equipment and industrial technologies for processing the materials, the development of certain branches of the economy, and scientific-technological progress as a whole. The paper discusses the stages of: invention of the first laser; creation of the first commercial lasers; development of the first applications of lasers in industrial technologies for processing the materials. Special attention is paid to the “patent wars” that accompanied different stages of the creation of lasers. A comparative analysis of the market development for laser technology from the stage of creation to the present has been carried out. Nineteenth-century world exhibitions were platforms to demonstrate technical and technological changes that witnessed the modernization and industrialization of the world. World exhibitions have contributed to the promotion of new inventions and the popularization of already known, as well as the emergence of art objects of world importance. One of the most important world events at the turn of the century was the 1900 World's Fair in Paris. Thus, the author has tried to analyze the participation of representatives of the sugar industry in the World's Fair in 1900 and to define the role of exhibitions as indicators of economic development, to show the importance and influence of private entrepreneurs, especially from Ukraine, on the sugar industry and international contacts. The article by Viktor Verhunov highlights the life and creative path of the outstanding domestic scientist, theorist, methodologist and practitioner of agricultural engineering K. G. Schindler, associated with the formation of agricultural mechanics in Ukraine. The methodological foundation of the research is the principles of historicism, scientific nature and objectivity in reproducing the phenomena of the past based on the complex use of general scientific, special, interdisciplinary methods. For the first time a number of documents from Russian and Ukrainian archives, which reflect some facts of the professional biography of the scientist, were introduced into scientific circulation. The authors from Kremenchuk National University named after Mykhailo Ostrohradskyi presented a fascinating study of a bayonet fragment with severe damages of metal found in the city Kremenchuk (Ukraine) in one of the canals on the outskirts of the city, near the Dnipro River. Theoretical research to study blade weapons of the World War I period and the typology of the bayonets of that period, which made it possible to put forward an assumption about the possible identification of the object as a modified bayonet to the Mauser rifle has been carried out. Metal science expert examination was based on X-ray fluorescence spectrometry to determine the concentration of elements in the sample from the cleaned part of the blade. In the article by Mykola Ruban and Vadym Ponomarenko on the basis of the complex analysis of sources and scientific literature the attempt to investigate historical circumstances of development and construction of shunting electric locomotives at the Dnipropetrovsk electric locomotive plant has been made. The next scientific article continues the series of publications devoted to the assessment of activities of the heads of the Ministry of Railways of the Russian Empire. In this article, the authors have attempted to systematize and analyze historical data on the activities of Klavdii Semyonovych Nemeshaev as the Minister of Railways of the Russian Empire. The article also assesses the development and construction of railway network in the Russian Empire during Nemeshaev's office, in particular, of the Amur Line and Moscow Encircle Railway, as well as the increase in the capacity of the Trans-Siberian Railway. The article discusses K. S. Nemeshaev's contribution to the development of technology and the introduction of a new type of freight steam locomotive for state-owned railways. We hope that everyone will find interesting useful information in the new issue. And, of course, we welcome your new submissions.
The excessively high atmospheric CO2 concentration is associated with rapidly evolving industrial, commercial, and residential uses of fossil fuels, which has caused global warming and climate crisis. Photocatalytic or electrocatalytic reduction of CO2 into value-added hydrocarbon fuels has provided a promising and sustainable solution to addressing these issues simultaneously. Multicarbon products (C2+) with higher energy densities are generally desirable in fueling transportation and other industries. However, the low selectivity and subsequently a higher cost toward these C2+ products have severely limited their larger scale production. Here, we review the strategies of controlling the C2+ product selectivity during the photocatalytic and electrocatalytic CO2 reduction reaction (CRR) processes with their catalytic reaction mechanisms. This review starts with the fundamentals on photocatalytic and electrocatalytic CRR, which is followed by discussions about how reaction mechanisms and process pathways affect the C2+ product selectivity and the main strategies to improve both photocatalysis and electrocatalysis systems. Finally, some outlook for future work and challenges in improving the C2+ product selectivity is included.
Materials of engineering and construction. Mechanics of materials
Magnesium (Mg) and its alloys as temporary medical implants with biodegradable and properly mechanical properties have been investigated for a long time. There are already three kinds of biodegradable Mg implants which are approved by Conformite Europeene (CE) or Korea Food and Drug Administration (KFDA), but not China Food and Drug Administration (CFDA, now it is National Medical Products Administration, NMPA). As we know, Chinese researchers, surgeons, and entrepreneurs have tried a lot to research and develop biodegradable Mg implants which might become other new approved implants for clinical applications. So in this review, we present the representative Mg implants of three categories, orthopedic implants, surgical implants, and intervention implants and provide an overview of current achievement in China from academic publications and Chinese patents. We would like to provide a systematic way to translate Mg and its alloy implants from experiment designs to clinical products. Keywords: Magnesium, Implant, Device, Biomedical translation, China
Materials of engineering and construction. Mechanics of materials, Biology (General)
Novel Fe68(MoWCrVCoNiAlCu)32 (at.%) medium-entropy high-speed steel (ME-HSS) coatings, containing various carbon contents from 0.65 to 1.05 wt%, are prepared by laser rapid solidification. The newly prepared ME-HSS coatings are characterized by a hard martensitic matrix enhanced by secondary hardening, and specifically by coherent nano-sized M2C. The secondary hardening effect is enhanced with the increasing carbon content. The high amount of alloying elements in ME-HSS coatings results in excellent oxidative wear resistance, without leading to serious compositional segregation and coarsening of carbides. Keywords: High speed steel, Coating, Medium-entropy alloy, Secondary hardening, Martensite
Materials of engineering and construction. Mechanics of materials
In the present research, polyaniline is used as a conducting polymer and polyvinyl alcohol is also used as a biopolymer, because of its mechanical properties and suitable processability. Also, silver nanoparticles are considered as a reinforcing agent of thermal stability, mechanical and antibacterial properties to prepare polyaniline-polyvinyl alcohol-silver nanocomposite. The synthesis of polyaniline-polyvinyl alcohol composite and polyaniline-polyvinyl alcohol-silver nanocomposite is performed through addition of polyaniline and silver in polyvinyl alcohol solution. In order to review thermal, mechanical and antibacterial properties of synthesized composite and nanocomposites, components with different weight rates are used. The obtained results from thermogravimetric analysis (TGA) tests also indicate promotion of thermal stability of polyaniline-polyvinyl alcohol-silver nanocomposite compared with pure polyvinyl alcohol in temperatures above 400°C. The results of Fourier-transform infrared (FTIR) spectroscopy revealed the presence of polyaniline, polyvinyl alcohol and silver in the structure of polyaniline-polyvinyl alcohol-silver triple nanocomposite film. The obtained results from a review of antibacterial properties showed that polyaniline-polyvinyl alcohol-silver nanocomposites have antibacterial effects on two different types of Gram-positive and Gram-negative bacteria. The obtained results from a review of mechanical properties of nanocomposites showed that the greatest value of tensile strength (13.8 MPa) belonged to polyaniline-polyvinyl alcohol-silver (88%/9%/3% w/w) nanocomposites. Therefore, this is determined as an optimal triple nanocomposite. In addition, scanning electron microscopy (SEM) coupled with an energy dispersive X-ray (EDX) system was used to characterize the composition and structure of polyaniline-polyvinyl alcohol-silver nanocomposite film.
Materials of engineering and construction. Mechanics of materials
The room-temperature shape of unsymmetric laminate due to the residual stress developed during the curing process has been investigated in the past decades. The factors influencing the residual stress of unsymmetric laminate, including moisture, fiber orientation, aspect ratio and ply thickness, have been widely investigated. Another mechanism that can generate residual stress is the interaction between the tool and the composite part during heating-up process. In this work, the effects resulting from the interaction between laminate and tool during the heating-up phase were considered. By introducing an interfacial shear stress due to tool-part interaction, an analytical model based on the Extended Classical Lamination Theory of Dano and Hyer was proposed to predict the room-temperature shapes of cross-ply unsymmetric laminates. The interfacial shear stress, which was correlated with experimental results, was introduced to tailor the amount of residual stress transferred from the tool. The model was validated with experimental data provided in the literature. It is shown that this model which takes the tool-part interaction into consideration could predict part processing deformations more accurately.
Materials of engineering and construction. Mechanics of materials
A number of large underground oil storage spaces will be constructed in deep salt mines in China in the coming years. According to the general geological survey, the first salt cavern oil storage base of China is planned to be built in Jintan salt mine. In this research, the geological feasibility of the salt mine for oil storage is identified in detail as follows. (1) The characteristics of regional structure, strata sediment, and impermeable layer distribution of Jintan salt mine were evaluated and analyzed. (2) The tightness of cap rock was evaluated in reviews of macroscopic geology and microscopic measuring. (3) According to the geological characteristics of Jintan salt mine, the specific targeted formation for building underground oil storage was chosen, and the sealing of nonsalt interlayers was evaluated. (4) Based on the sonar measuring results of the salt caverns, the characteristics of solution mining salt caverns were analyzed. In addition, the preferred way of underground oil storage construction was determined. (5) Finally, the results of closed well observation in solution mining salt caverns were assessed. The research results indicated that Jintan salt mine has the basic geological conditions for building large-scale underground oil storage.
Materials of engineering and construction. Mechanics of materials