Martin Bellmann, Berhane Darsene Dimd, Anne‐Karin Søiland
et al.
In the ICARUS project, European partners collaborate to develop and scale innovative technologies for recovering and refining secondary raw materials from silicon photovoltaic (PV) manufacturing. The production of photovoltaic modules generates significant quantities of waste, particularly silicon kerf, graphite, and silica residues from ingot and wafer manufacturing. ICARUS aims to transform these waste streams into high‐value secondary materials suitable for reintegration into the PV value chain and other industrial applications. Four industrial pilot‐scale processes are developed, targeting the purification and reuse of these materials. Results from the pilots demonstrate both the technical feasibility and economic potential of substituting these recovered materials for virgin and critical raw materials. This work provides a viable pathway toward a more resource‐efficient and circular PV manufacturing industry.
Environmental technology. Sanitary engineering, Renewable energy sources
Roberto López-Chila, Henry Abad-Reyna, Joao Morocho-Cajas
et al.
Standardized driving cycles such as the FTP-75 fail to represent traffic conditions in cities like Guayaquil, where high congestion and varied driving behaviors are not captured by external models. This study aimed to develop representative driving cycles for the city’s most congested urban routes, covering the north, south, center, and west zones. Using the direct method, real-world trips were conducted with an M1-category vehicle equipped with an OBDLINK MX+ device, allowing real-time data collection. Driving data were processed through OBDWIZ software Version 4.30.1 and statistically analyzed using Minitab. From pilot tests, the appropriate sample size was estimated, and normality tests were applied to determine the correct measures of central tendency. The final representative cycles were constructed using a weighting criteria method. The results provided quantified evidence of variations in average speed, idle time, and acceleration patterns across the routes, which were transformed into representative driving cycles. These cycles provide a more accurate basis for emission modeling, vehicle certification, and transport policy design in congested cities such as Guayaquil, and this is the applied impact that is highlighted in our contribution. Furthermore, the developed cycles provide a foundation for future research on emission modeling and the design of sustainable transport strategies in Latin American cities.
Mechanical engineering and machinery, Machine design and drawing
Phillip Ormeño Vásquez, Naysha Rojas Villa, Cristian Rojas Villa
Tourism and hospitality education in Peru is evolving to incorporate a stronger focus on environmental conservation. In this context, this study aims to assess environmental conservation attitudes of students enrolled in tourism and hospitality programs offered by Peruvian universities. A descriptive, cross-sectional study was carried out among students pursuing a degree in Tourism and Hospitality Management at the National University of Cañete, in Lima, Peru. The research focused on the period from July to December 2018. The final report was completed in 2020. A sample of 45 students was taken from a total population of 281, based on specific selection criteria. The demographic variables considered for this study were: age group, gender, and class shift, alongside the following dimensions: cognitive, affective and reactive. The majority of participants were female (73.3%), within the 20- to 22-year-old group (80.0%), and attended morning classes (64.4%). The highest level of agreement among students was observed for the statement that local hotels should implement appropriate waste management systems (item 2). Furthermore, 86.7% of respondents strongly agreed that plants and animals have the same right to life as human beings (item 20). Similarly, 60.0% of them indicated they would be willing to mobilize others in support of public space conservation (item 26). Overall, the findings suggest that students possess sound cognitive and affective attitudes towards environmental conservation. However, a lower reactive performance requires strategies to foster a deep emotional connection.
در این مقاله، ارتعاشات غیرخطی یک تیر با تکیه گاه ساده که یک NES دوپایا (چاه انرژی غیرخطی) به صورت محلی به آن متصل است، بررسی شده است. این مطالعه بر روی تأثیرات رزونانس داخلی بر رفتار دینامیکی تیر و چگونگی کنترل ارتعاشات توسط چاه انرژی غیرخطی (NES) متمرکز استNES . های دو پایا به دلیل کارایی آنها در مقایسه با NES های تک پایا به طور گسترده ای مورد استفاده قرار می گیرند. در چنین مسائلی، تشدیدهای داخلی اجباری که در آن مقدار انرژی وارد شده از تیر به NES به اندازه کافی بزرگ است، بسیار مورد توجه است. معادلات حرکت سیستم با استفاده از روش نیوتن بدست آمده و پس از بی بعد کردن معادلات حرکت سیستم، روش گالرکین برای گسسته سازی معادلات حرکت بکار رفته است. در ادامه، با استفاده از روش مقیاس های چندگانه (MMS)، رزونانس داخلی اولیه 1:3 مورد بررسی قرار گرفته است. نتایج نشان میدهد که منحنیهای پاسخ فرکانسی به شدت تحتتاثیر تغییرات جزئی در پارامترهای NES، بهویژه میرایی قرار میگیرند. با این حال، به دلیل رفتار NES در حوزه فرکانس که بر خلاف تیر نرم شونده است، محدودیت های اعمال شده فیزیکی ناشی از جابجایی جرم NES می تواند بر کارایی آن تأثیر منفی بگذارد. و همچنین استفاده از NES در تیرها میتواند به طور قابل توجهی پایداری دینامیکی را بهبود بخشد و عمر مفید سازهها را افزایش دهد. یافتههای این مطالعه میتواند به طراحی بهینهتر و استفاده مؤثرتر از NES در کاربردهای مهندسی کمک کند.
AbstractExcavator bucket teeth are often in direct contact with abrasive particles in the soil during work, resulting in the tip being severely worn. This study used laser cladding to synthesize (Ti, Nb)C reinforced coatings on the surface of Q550 steel of bucket teeth of commonly used excavators to improve the wear resistance, and researches the effects of different Ti, Nb, Cr3C2 powder ratios on the hardness, wear resistance, and wear loss of laser cladding (Ti, Nb)C reinforced coatings. The results show that the optimal powder ratio is 80% Ni-based + 1.26% Ti + 7.54% Nb + 11.2% Cr3C2. Under the optimal powder ratio, the hardness of the coating is 213.4 HV, the wear amount is 32.7 mg, and the wear failure form is abrasive wear and slight adhesive wear.
Kizuku KUROSE, Shuichi UMEZAWA, Kazushi MIYATA
et al.
Superheaters are essential components in a coal-fired power plant because they keep the highest tube wall temperature points in the radiant boiler. The pressurized steam flowing in the superheater tubes is heated via the thermal radiation and convection from the combustion gas. To prevent the bursting of superheater tubes caused by the thermal fatigue for stable and safe plant operation, precisely predicting complex heat transfer characteristics, and estimating the local temperature and heat flux of the superheater are necessary. In this study, a computational fluid dynamics model of the boiler and the second and third superheaters in a coal-fired power plant is developed using radiation model (DO model) and turbulence models (k-ε RNG model). In the second superheater installed near the burner, the influence of radiation from the combustion gas is strong, and the temperature and heat flux of the outermost tube are highest. In the third superheater, the tube wall temperature and heat flux becomes large in the upper and middle parts of the superheater, where the combustion gas flow velocity around the superheater is high, whereas those at the bottom of the superheater are significantly small due to the dead water region of the gas. Therefore, to consider the combustion gas flow is important for prediction of the heat transfer characteristics of the third superheater.
Mechanical engineering and machinery, Engineering machinery, tools, and implements
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
Christian Rosenberg Petersen, Søren Fæster, Jakob Ilsted Bech
et al.
Abstract Leading edge erosion of wind turbine blades is one of the most critical issues in wind energy production, resulting in lower efficiency, as well as increased maintenance costs and downtime. Erosion is initiated by impacts from rain droplets and other atmospheric particles, so to protect the blades, special protective coatings are applied to increase their lifetime without adding significantly to the weight or friction of the blade. These coatings should ideally absorb and distribute the force away from the point of impact; however, microscopic defects, such as bubbles, reduce the mechanical performance of the coating, leading to cracks and eventually erosion. In this work, mid‐infrared (MIR) Optical Coherence Tomography (OCT) is investigated for non‐destructive, contactless inspection of coated glass‐fiber composite samples to identify subsurface coating defects. The samples were tested using rubber projectiles to simulate rain droplet and particle impacts. The samples were subsequently imaged using OCT, optical microscopy, and X‐ray tomography. OCT scanning revealed both bubbles and cracks below the surface, which would not have been detected using ultrasonic or similar non‐destructive methods. In this way, OCT can complement the existing quality control in turbine blade manufacturing, help improve the blade lifetime, and reduce the environmental impact from erosion.
The corrugated lobed nozzle is an emerging research topic in jet flow dynamics, and little investigation has been conducted on its effect on flow characteristics. Thus, in this study, the effects of lobe count and lobe length of corrugated lobed nozzles on subsonic jet characteristics were experimentally investigated by analyzing the velocity profiles of the jets emanating from the nozzles. The Pitot tube readings were obtained by varying the count (4 ≤ N ≤ 8) and length (10 mm ≤ L ≤ 20 mm) of corrugated lobes. These measurements were then compared with the experimental readings obtained for a baseline circular nozzle. The nozzle pressure ratio (NPR) and exit nozzle area were kept identical at 1.5 and 600 mm2, respectively, for all nozzle configurations. The most striking observation was the ‘W’-shaped radial velocity profile of the corrugated nozzle, which differed from the ‘Top hat’ profile of the baseline circular nozzle. Additionally, the length of the potential central region of the corrugated nozzle was always shorter than that of the baseline circular nozzle, indicating the early occurrence of turbulence in the former. It was found that the lobe length had a meagre effect on the velocity variation in the jet issuing from the corrugated nozzle, whereas the lobe count had a significant effect on the velocity profile. However, as the lobe count increased, the velocity profile of the corrugated nozzle gradually resembled that of the circular nozzle. The findings of this study would be beneficial for selecting a proper lobe count and lobe length while designing and implementing a corrugated lobed nozzle.
G Harish Kumar Varma, Venugopal Reddy Barry, Rohit Kumar Jain
et al.
Abstract Partial shading is a severe impediment to the effective use of photovoltaic systems. It will lead to performance degradation in the photovoltaic system. This work proposes a maximum–minimum tier equalisation swapping reconfiguration algorithm for total‐cross‐tied connection under shading conditions. The proposed reconfiguration algorithm uses a switch matrix to alter the interconnection of modules in a photovoltaic array. The switch matrix dynamically modifies the connections based on the equalisation of tier irradiance. This algorithm applies to the symmetrical and asymmetrical photovoltaic array. Further, simulation studies show the efficacy of the proposed algorithm by minimising the multiple peaks and enhancing the output power compared with the traditional total‐cross‐tied configuration. The performance of experimental tests ascertains the feasibility of the proposed method.
Shuyu Tian, Rory Stevens, Bridget T. McInnes
et al.
Optimization of extrusion-based bioprinting (EBB) parameters have been systematically conducted through experimentation. However, the process is time- and resource-intensive and not easily translatable to other laboratories. This study approaches EBB parameter optimization through machine learning (ML) models trained using data collected from the published literature. We investigated regression-based and classification-based ML models and their abilities to predict printing outcomes of cell viability and filament diameter for cell-containing alginate and gelatin composite bioinks. In addition, we interrogated if regression-based models can predict suitable extrusion pressure given the desired cell viability when keeping other experimental parameters constant. We also compared models trained across data from general literature to models trained across data from one literature source that utilized alginate and gelatin bioinks. The results indicate that models trained on large amounts of data can impart physical trends on cell viability, filament diameter, and extrusion pressure seen in past literature. Regression models trained on the larger dataset also predict cell viability closer to experimental values for material concentration combinations not seen in training data of the single-paper-based regression models. While the best performing classification models for cell viability can achieve an average prediction accuracy of 70%, the cell viability predictions remained constant despite altering input parameter combinations. Our trained models on bioprinting literature data show the potential usage of applying ML models to bioprinting experimental design.
Due to the mismatch of main circuit parameters and the negative impedance characteristics of inverter-motor system under specific operating conditions, urban rail transit traction system is prone to DC-link voltage oscillation. In order to solve this problem, this paper establishes a characteristic equation model of traction system, and analyzes the influence of DC-link filter parameters on system stability. For inverter-motor drive system, it proposes an oscillation suppression method based on impedance reconstruction. By compensating d axis and q axis reference voltage signal of controller, negative impedance characteristic of the inverter-motor system is improved so that the system is stable. Simulation and hardware-in-the-loop experiment results show that the suppression strategy can effectively suppress the oscillation and improve the stability of system.
Control engineering systems. Automatic machinery (General), Technology
Mechanical engineering is an engineering discipline that uses the laws of physics to analyze, design, manufacture and maintain mechanical systems. Mechanical engineering is an applied discipline, which is based on the relevant natural science and technical science, combined with the technical experience in production practice, to study and solve all the theoretical and practical problems in the development, design, manufacture, installation, application and maintenance of various kinds of machinery. Under the background of “new engineering” and “made in China 2025”, it is necessary to explore and improve the professional ability of mechanical students. As the fresh blood of the machinery industry, the mechanical students should maximize their professional quality through social practice and other ways. According to the demand for mechanical talents in the Middle East of Inner Mongolia and the teachers' ability of local universities, this paper puts forward the “Trinity” training mode of students' innovative practical ability of mechanical design and manufacturing and automation specialty.
In the field of mechanical equipment manufacturing, the focus of research and development is not on weight reduction, but on how to choose between the rigidity and performance of components (such as strength or flexibility). For this contradiction, lightweight is one of the best solutions. The problems associated with lightweight were initially considered and systematically studied in aircraft manufacturing in engineering. Therefore, lightweight has been greatly developed in aviation research and has played an increasingly important role in construction machinery. This paper presents a brief description of the current status of lightweight in machinery by reviewing some significant progress made in the last decades. Potential research topics are also discussed from the four aspects of material, structure, bionics, and manufacturing, and they forecast the development trend of lightweight in the future construction machinery. The entire body of literature about the field is not covered due to the limitation of the length of paper. The scope of this review is limited and closely related to the development of lightweight technology in engineering applications.
ABSTRACT Li, B. and, Yang, H., 2020. Design of active vibration reduction system for intelligent ship mechanical equipment. In: Bai, X. and Zhou, H. (eds.), Advances in Water Resources, Environmental Protection, and Sustainable Development. Journal of Coastal Research, Special Issue No. 115, pp. 235-237. Coconut Creek (Florida), ISSN 0749-0208. An intelligent shock absorber with active-passive compound and integrated sensing action is developed for engineering needs. It's based on the traditional passive isolation structure, the active actuator, power amplifier, high and low pass filter, acceleration error sensor and subsequent amplifier and filter circuits are integrated. An active damping system for ship machinery equipment is constructed with an active controller running offline. Based on the system, a demonstration platform for active vibration reduction of diesel generator set is established. The entire bench is mounted on an elastic steel plate simulating the hull structure through four intelligent shock absorbers, the vibration performance of the active vibration reduction system is evaluated by measuring the vibration of the elastic steel plate. The demonstration bench test results show that The total vibration level of the intelligent shock absorber within 800 Hz has a passive vibration reduction effect of more than 33 dB, Based on this, active control has a good control effect on multiple lines within 200 Hz, A maximum active attenuation of 30.8 dB, The active attenuation of total vibration level within 200Hz reaches 20 dB.. Synthesizing the effects of active and passive vibration reduction, the intelligent shock absorber can attenuate the total vibration level of the diesel generator set of the demonstration bench O∼ more than 47.2 dB in the range of 800 Hz.
At this stage, China has increased its research efforts in mechanical and electronic technology, which has also promoted the application advantages of mechanical automation in various industries, and the same is true in the food packaging industry. Based on previous work experience, the author summarizes the necessity of automatic control of food packaging machinery. This article discusses the application of mechanical automation in the field of food packaging from four aspects: automatic control form of food packaging machinery, automatic controller of food packaging machinery, application of drive and sensor technology, and application of automatic identification technology.
At present, the domestic engineering industry as a whole and mining machinery manufacturing in particular undergo a difficult period due to the imposition of sanctions and the ensuing crisis economic phenomena. In the absence of an acceptable rate of import substitution caused by the low competitiveness of manufactured products, mechanical engineering enterprises are forced to look for ways to ensure the production of modern mining equipment that meets the requirements of consumers. This is especially important in light of growing trends of the transition from raw materials export to the industry-oriented line of development of the domestic economy. In the face of a decrease in the share of mechanical engineering in the gross product of the Kemerovo region by several times in recent years, it is imperative to increase the competitiveness of mechanical engineering enterprises. For the successful achievement of this objective, it is important to update the existing manufacturing facilities, including through the introduction of new advanced technologies. Based on this, an important and urgent task aimed at improving the rate of domestic production is the search, substantiation and implementation of innovative competitive technologies in mining machinery manufacturing. One of the promising areas in this field is to increase the efficiency of abrasive machining of mining equipment parts during tumbling operations.