Hasil untuk "Mechanical industries"

Sherali Jalilov, Gulbahor Khudoynazarova, Firuz Muzaffarov et al.

In this paper, we consider a method for producing wood-plastic composites (WPC) based on urea-formaldehyde resins (UFR) and investigate their physical and mechanical properties. The composition and technology of production of a wood-polymer composite, including the preparation of raw materials, mixing of components, molding and curing, are given. Methods for estimating density, flexural strength, water absorption, and resistance to external influences are described. The influence of various parameters on the properties of the obtained material is analysed. The results of the study make it possible to optimize the manufacturing technology of WPC with improved characteristics for use in the construction and furniture industries.

Ifigenia Psarra, Adrian Figueroa, Esperance Mfurakazi et al.

Abstract Background This research study applied the 'Integrated Energy Landscape Approach and the Ecosystem Services Framework' to formulate a pre-proposal for a Positive Energy District in the Hoogkerk Zuid neighborhood in Groningen, the Netherlands. Results The proposed energy saving and energy generation interventions are sufficient to cover the energy usage of the district, while an energy surplus is generated. The pre-proposal has been developed within a participatory process, organized by the authors in close collaboration with key local stakeholders. The identification of local ecosystem services served as a crucial starting point for this study, while it also served for the basis for analysing the subsequent trade-offs and synergies derived from the proposed energy transition interventions. Then, a sustainable business case model was developed based on this Positive Energy District pre-proposal. The main outcome of the model lies in the value creation through cost savings from not using traditional energy sources and selling electricity to the grid. In addition, the economic value of the preserved ecosystem services and of the synergies generated by the pre-proposal are also included in the model. Conclusions Beyond the local case, the results lay the groundwork for more systematic studies on merging the methodologies of Positive Energy District development, the Ecosystem Framework and the Integrated Energy Landscape approach. Finally, by adding the benefits of ecosystem services and synergies as a significant contributor in the financial analysis and decision-making process, this study opens the door to a new approach to the evaluation of sustainable projects.

Yuxin Yang, Mei Zhang, Wei Ma et al.

This study aims to help researchers quickly understand the latest research status of kiwifruit picking robots to expand their research ideas. The centralized picking of kiwifruit is confronted with challenges such as high labor intensity and labor shortage. A series of social issues including the decline in agricultural population and population aging have further increased the cost of its harvest. Therefore, intelligent picking robots replacing manual operations is an effective solution. This paper, through literature review and organization, analyzes and evaluates the performance characteristics of various current kiwifruit picking robots. It summarizes the key technologies of kiwifruit picking robots, from the aspects of robot vision systems, mechanical arms, and the end effector. At the same time, it conducts an in-depth analysis of the problems existing in automatic kiwifruit harvesting technology in modern agriculture. Finally, it is concluded that in the future, research should be carried out in aspects such as kiwifruit cluster recognition algorithms, picking efficiency, and damage cost and universality to enhance the operational performance and market promotion potential of kiwifruit picking robots. The significance of this review lies in addressing the imminent labor crisis in agricultural production and steering agriculture toward intelligent and precise transformation. Its contributions are reflected in greatly advancing robotic technology in complex agricultural settings, generating substantial technical achievements, injecting new vitality into related industries and academic fields, and ultimately delivering sustainable economic benefits and stable agricultural supply to society.

Yuan Feng, Ying Miao, Ed Turner

Abstract Background Domestic energy consumption contributes to over a quarter of the UK’s carbon emissions, understanding how it is driven can be helpful for delivering a fair energy transition to net zero. Energy usage is noted as a spatial phenomenon, however, the spatial variability of how it is driven is rarely considered in existing UK studies. To contribute to this research gap, this study examines the spatial variations in the relationship between domestic energy consumption and its driving factors using the local spatial statistical modelling technique multiscale geographically weighted regression (MGWR). With explanatory variables on dwelling and household characteristics, this study analyses data at Lower Layer Super Output Area (LSOA) level on the study area, Nottingham, a somewhat socio-economically deprived city that also has the UK’s largest district heating (DH) system supplying low-carbon residential heating. Results The study reveals domestic energy consumption is driven by factors at different spatial scales with spatially varied or even spatially heterogeneous patterns. Specifically, higher domestic energy consumption is affected differently across local areas by larger percentages of dwellings with 4 or more bedrooms, unemployment, terraced dwellings, whilst by smaller percentages of social-rented housing tenures and central heating type of district heating. The impacts of dwelling energy efficiency, median household income, percentage of households with 3 or more people, fuel poverty, and central heating with renewable energy, vary across different local areas. Therefore, while there are identifiable relationships between these factors and domestic energy consumption, they differ by locality, and aggregated level analysis may fail to accurately to capture these patterns. Conclusions Nuanced local patterns of how domestic energy consumption is driven suggest placed-based approaches and more local deliberation to devise policies may be more suitable than “one-size-fit-all” policy plans to achieve the envisioned outcomes of rapid and fair domestic energy decarbonisation and just energy transition to net zero.

Jiangchao WANG, Shizhong DU, Xiangfei CHEN et al.

ObjectiveIn order to effectively control flame cutting precision of thin plate with high tensile strength steel, Generation mechanism of out-of-plane buckling distortion and in-plane bending distortion were investigated, and processing with dynamic heating was proposed to reduce flame cutting distortion. Method Using Q550 plate with thickness of 3 mm as research object, out-of-plane buckling and in-plane bending distortion of examined cutting specimen were observed by means of flame cutting experiment and 3-dimensional measurement. By thermal elastic plastic FE computation with large deformation, thermomechanical response during flame cutting of Q550 thin plate was examined, and influence of additional heating on flame cutting distortion of thin plate with high tensile strength steel was also considered. ResultsBoth distortion tendency and magnitude of predicted results are in excellent agreement with measured data. In addition, heating the region away from flame cutting can reduce buckling distortion about 90% and in-plane bending distortion by 40%. ConclusionsBased on the generation mechanism of cutting distortion, assisted flame heating with different processing was proposed and applied to improve the cutting accuracy with flame; furthermore, with thermal elastic plastic FE computation, optimal processing to reduce flame cutting distortion was proposed for high-precision fabrication of thin plate with high tensile strength steel.

Yupu Dai, Joel Chong, Ling Chen et al.

Springs are widely used in industries such as aerospace and automotive. As the demand for emission reduction grows, the research on lightweight spring performance is becoming increasingly important. This study analyses the mechanical performance of triple-layer braided composite helical springs (TCHS) under various loads and compression angles. Firstly, the optimal high-temperature curing condition of the epoxy resin was determined through tensile and three-point bending analysis. Then, TCHS were fabricated based on optimal epoxy curing conditions, and multi-angle compression tests under different loads were carried out. Simultaneously, strain gauges were installed at various positions and orientations on the inner and outer sides of the spring wire to reveal strain patterns during the compression. The test results indicate that stiffness decreases with increasing compression angle. Additionally, the strain in the inner and outer positions in different directions of the same region increased with the rise in compression force and angle, and strains in the helical direction were the largest. Subsequently, strain in the helical direction across different regions further showed that maximum strain occurred in the centre coil (region 2), with inner and outer helical direction strains reaching −5116.89 με and 5700.15 με, respectively, which are 71.3% and 90.4% higher than those in region 1 and 73.2% and 92.9% higher than those in region 3. As the compression load increased, cracks appeared on the outer side of the centre coil. In addition, the crack was perpendicular to the helical direction, further confirming that the highest strain occurred in the helical direction. This study provides an in-depth analysis of the impact of angle-specific loads on TCHS, offering valuable insights for the design and optimisation of composite helical springs and laying a theoretical foundation for their future development.

Ming Ding, Chunwei Yang, Yifan Bai et al.

The flat linear induction pumps (FLIPs) are a class of driving devices that converts electromagnetic energy into mechanical energy of pumped liquid metal, which are widely used in the field of energy power and chemical industries. The end effects and wall eddy current effect of FLIPs can significantly reduce the pump head and energy conversion efficiency. In this paper, the longitudinal and transverse end effects of FLIPs caused by the finite length of the core were analyzed, and the analytical expressions of the electromagnetic field in the electromagnetic air gap were given. Based on the mathematical analysis of the end effects and the T-shaped equivalent circuit of the rotary induction motor, an equivalent circuit model was established, considering two kinds of end effects and wall eddy current effects. The calculation methods of main characteristic parameters, such as head and energy conversion efficiency, were given. The accuracy of the analytical model was validated by comparing the calculation results with the open experimental data. The work can provide a rapid analysis method for improving the energy conversion efficiency and working performance of FLIPs.

JoAnn Ballor, Jonathan D. Poplawsky, Arun Devaraj et al.

β-titanium (β-Ti) alloys are useful in diverse industries because their mechanical properties can be tuned by transforming the metastable β phase into other metastable and stable phases. Relationships between lattice parameter and β-Ti alloy concentrations have been explored, but the lattice parameter evolution during β-phase transformations is not well understood. In this work, the β-Ti alloys, Ti-11Cr, Ti-11Cr-0.85Fe, Ti-11Cr-5.3Al, and Ti-11Cr-0.85Fe-5.3Al (all in at.%), underwent a 400 °C aging treatment for up to 12 h to induce the β-to-ω and β-to-α phase transformations. Phase identification and lattice parameters were measured in situ using high-temperature X-ray diffraction. Phase compositions were measured ex situ using atom probe tomography. During the phase transformations, Cr and Fe diffused from the ω and α phases into the β matrix, and the β-phase lattice parameter exhibited a corresponding decrease. The decrease in β-phase lattice parameter affected the α- and ω-phase lattice parameters. The α phase in the Fe-free alloys exhibited α-phase c/a ratios close to those of pure Ti. A larger β-phase composition change in Ti-11Cr resulted in larger ω-phase lattice parameter changes than that for Ti-11Cr-0.85Fe. This work illuminates the complex relationship between diffusion, composition, and structure for these diffusive/displacive transformations.

Geethapriyan Thangamani, Stefano Felicioni, Elisa Padovano et al.

In recent years, additive manufacturing (AM) has played a significant role in various fashion industries, especially the textile and jewelry manufacturing sectors. This review article delves deeply into the wide range of methods and materials used to make intricately designed jewelry fabrication using the additive manufacturing (AM) process. The Laser Powder Bed Fusion (L-PBF) process is examined for its suitability in achieving complex design and structural integrity in jewelry fabrication even with respect to powder metallurgy methods. Moreover, the review explores the use of precious materials, such as gold, silver, copper, platinum, and their alloys in additive manufacturing. Processing precious materials is challenging due to their high reflectivity and thermal conductivity, which results in poor densification and mechanical properties. To address this issue, the review article proposes three different strategies: (i) adding alloying elements, (ii) coating powder particles, and (iii) using low-wavelength lasers (green or blue). Finally, this review examines crucial post-processing techniques to improve surface quality, robustness, and attractiveness. To conclude, this review emphasizes the potential of combining additive manufacturing (AM) with traditional craftsmanship for creating jewelry, exploring the potential future directions and developments in the field of additive manufacturing (AM) for jewelry fabrication.

Kennedy Manduna

Habeeb Al-Ani

Surface roughness is a key parameter to consider in the machining of aluminum alloy. It is rendered as one of the important determinants of the performance of mechanical instruments or components. Owing to its excellent mechanical properties, and ease of machinability, Aluminum 6061 (Al6061) is rendered a popular choice in many industries. Achieving a desired surface finish is crucial for the performance and longevity of machined components. This study aimed to compare the predictive performance of the artificial neural network (ANN) model versus the response surface methodology (RSM) in the prediction of surface roughness in the turning process of Al6061. ANN performed better than RSM in the prediction of surface roughness (A20 index 0.93 and 0.86 for ANN and RSM models respectively). MAPE and sMAPE were also found to be lower in the ANN model compared with the RSM model (8.06 versus 9.69, and 0.039 versus 0.047 respectively) indicating that the ANN model had a better predictive performance compared with the RSM model. Both ANN and RSM models showed that cutting speed and feed rate were the most important determinants of surface roughness in the turning process of Al6061 in other words to achieve a smoother surface during the turning process of Al6061 high cutting speed and low feed rate should be used. The findings of this study reflect the potential utility of ANN in the prediction and subsequently optimizing cutting parameters to achieve a smoother surface.

Jiahui Pu, Nan Jiang, Yulan Zhang et al.

Abstract Returning straw to the field is an effective method for optimizing the soil phosphorus (P) availability, in which bacteria play an important role. However, the effects of various straw incorporation strategies on P transformation between different soil P pools remain unclear. In this study, variations in soil P fractions, phosphatase activities and the abundance of phosphatase genes (phoD, phoX and phoC) as well as a P‐solubilizing gene (pqqC) at DNA (total) and cDNA (transcribed) levels were analysed in three straw incorporation treatments, including chopped straw (StrawD), straw compost (Compost) and straw‐derived biochar (Biochar), and control (no straw, CK). Compared with the CK, the moderately labile inorganic P (NaOH I‐Pi) content significantly decreased and the non‐available P (Residual P) content significantly increased in the StrawD treatment. At the same time, phosphodiesterase (PD) activity and the transcribed phoC and phoX genes as well as total pqqC gene abundance significantly increased in the StrawD treatment, suggesting that the input of chopped straw stimulated P transformations from both organic and inorganic P pools. In addition, the stable Pi (NaOH II‐Pi) content and total pqqC gene abundance in the Biochar treatment were significantly higher than that in the CK, indicating that the input of biochar increased the NaOH II‐Pi that could release available P by Pi‐solubilizing bacteria. In comparison to the CK, the Compost input significantly decreased one labile Pi (resin‐Pi) only. However, its P fractions were significantly different from that of CK, Biochar and StrawD treatments, suggesting that the effects of compost input on P should not be ignored. In conclusion, chopped straw input increased soil P transformation but not available P, biochar input may promote inorganic P transformation, and compost input has a latent effect on P transformation. The study provided a comprehensive understanding of straw incorporation strategies for regulating soil P availability.

Marat R. Safiullin, Aliya A. Gataullina, Leonid A. Elshin

The exhaustion of the traditional raw material export model, which results in a growing dependence of the core economic industries on imported goods and components, makes it increasingly relevant to develop tools for finding promising areas of import substitution. The paper proposes a methodology for assessing imported commodity groups to identify the priority areas for import substitution in a region. The theoretical framework of the study includes comparative and competitive advantage theories, as well as the concepts of production concentration, clusters, and industrial complexes. The research methods of economic-statistical, structural analyses and clustering were applied. The statistical data were retrieved from the Federal Customs Service of the Russian Federation, the Federal State Statistics Service (Rosstat), and the Unified Interdepartmental Statistical Information System (EMISS). The proposed methodology was tested using the case of imports and exports in the Republic of Tatarstan in 2013–2021. We identified four key commodity clusters for import substitution, which account for more than 40 % of the region’s current imports, these are 1) the important localized import-dependent commodity groups a) having potential for import substitution in the region (tools, petroleum products), b) promising for import substitution in the RF (equipment and mechanical devices, furniture), as well as 2) the important non-specific import-dependent commodities a) having potential for import substitution (paints, electrical machines), and b) promising for import substitution (milk, clothing). The largest producers of the Republic of Tatarstan were identified for each cluster. Matrix modeling showed that some commodity groups are positioned in the area of the region’s low specialization, low localization and share of imports, which are typically grouped into three additional clusters that do not require enhanced policy on import substitution: growing import-dependent goods (grain, etc.), goods requiring no particular attention (silk, wool, etc.), and significant import-dependent goods (essential oils, etc.). The research findings can be used by regional ministries and departments when making strategic decisions on import substitution.

Songbai Zhu, Jian Dai, Guolai Yang et al.

In real life, only partial information of samples is available everywhere, this makes Incomplete multi-view clustering (IMVC) becomes a significant research topic to handle data loss situations. Recently, several methods leverage the anchor strategy by selecting fixed anchors to handle the challenging large-scale IMVC. However, all of them ignore the guidance of prior information hidden in the bipartite graph. Therefore, we propose a novel Anchor Pseudo-supervise Large-scale Incomplete Multi-view Clustering (AP-LIMC) method by introducing a prior indicator matrix as a pseudo-supervise anchor learning paradigm. Specifically, the prior indicator matrix is first introduced to control the distribution of anchors in each cluster. Then, an anchor pseudo-supervise learning framework is designed to generate high-quality anchors and a unified bipartite graph with prior indicator supervision. In addition, we design an optimized process with linear computational and extensive experiments on multiple public datasets with recent advances to validate the effectiveness, superiority, and efficiency. For example, on the Stl10 dataset, the performance of the proposed AP-LIMC improved by 23.95%,15.71%,27.39%, and 18.24% in terms of four evaluation metrics, respectively.

Naufal Rospriandana, Paul J. Burke, Amalia Suryani et al.

Abstract Background Hydropower is a mature energy technology and one that could play a more important role in providing clean and reliable energy. In small-scale contexts, hydropower is useful for providing electricity access, balancing intermittent resources, and as a potential source of energy storage. This paper provides a comprehensive exploration of the development of the small hydropower (SHP) sector in Indonesia, the world’s fourth most populous country. Methods Two research methods were employed: secondary data analysis through a desk review of relevant literature and primary data collection through site visits and expert and stakeholder interviews. Two case studies of micro-hydro applications in community-based rural electrification were analyzed. The paper explores how SHP projects were initiated, lessons learned, and policy recommendations of relevance to further development of distributed small-scale renewable energy in Indonesia. Results The sector commenced during the Dutch Era and now centers on both community-based rural electrification projects and commercial schemes under the independent power producer (IPP) approach. Since the late 1980s, initiatives to implement SHP for rural electrification have flourished through various programs. Key regulatory, economic, and technical barriers include inconsistent and unclear supporting regulations, especially regarding electricity prices; artificially low retail electricity prices; capital and borrowing constraints; advantages provided to fossil fuels; limited technical experience and capabilities of project developers and project sponsors; risks from floods, earthquakes, and landslides; constraints on supporting infrastructure; and limited grid links. The most successful and sustainable SHP projects are ones that provide local economic benefits and for which local communities are empowered with ownership and have responsibility for maintenance. Conclusions SHP will remain small from a macro perspective but could still play a key role in further improving energy access and equity in remote areas. Key initiatives to facilitate this development could include local-level capacity building and project participation and the adequate pricing of negative externalities from fossil fuel projects. Indonesia’s long experience with SHP carries lessons for other developing countries.

Xiaodong Gao, Nana He, Ruhao Jia et al.

Abstract China's Loess Plateau (LOP) contains around 22% of all the world's apple trees, mainly on smallholdings run by farmers. However, business‐as‐usual (BAU) intensification has reduced the ecological resilience of orchards. Agroforestry is considered to be an important method of realizing sustainable intensification of agroecosystems. However, the design of practical agroforestry systems in drylands remains poorly researched. We hypothesized that crop density is a key factor in designing dryland apple tree‐based agroforestry systems. We carried out an experiment in apple orchards in the semiarid LOP, where the bioenergy crop canola (Brassica napus L.) was intercropped at low, medium, and high densities with row spacings of 25, 50, and 100 cm, respectively, to study its effects on water, carbon, and production. We found that intercropping of canola at different densities clearly decreased soil water content (SWC) in the top 60 cm soil layer at all sampling locations, reduced midday leaf water potential (Ψm) and leaf water content (LWC), and caused apple trees to produce more fine roots at greater depths. However, intercropping did not affect SWC in soil layers below 60 cm. The SWC profiles, Ψm and LWC, progressively recovered over the mulching period. Introduction of canola also significantly (p < 0.05) increased SOC content in the surface layer, an effect less visible in deeper layers, and increased the quality of apple fruit to varying degrees while not affecting apple yield measurably. Overall, higher intercropping density does not lead to severer water deficit but have better carbon sequestration benefit than lower density, and therefore seems more appropriate in our study site. Our findings provide solid evidence that agroforestry helps achieve sustainable intensification of dryland orchards.

Dong-fang Li, Zhao-hui Mao

Based on the theory of elastic fracture and using direct modeling method, a numerical model was developed for solving the composite stress intensity factor of semi-elliptical cracks on exchanger outer walls with inclined angles. The model exchanger had an outer diameter of φ50 mm, inner diameter of φ44 mm and length of 300 mm. The values of crack plane inclination β (0°, 10°, 20°, 30°, 40° and 45°), crack depth a (0.5 mm, 0.75 mm, 1 mm and 1.25 mm), and crack shape ratio a/b (0.4, 0.5, 0.55, 0.6, 0.7, 0.8, 0.9 and 1.0) were obtained and 3D surface crack model was established. The results were significance for the evaluation of the remaining life of exchanger components.

Chilenye Nwapi, Chinwe Ezeigbo, Oluwakemi Oke

J. Ayllón, V. Miguel, A. Martínez-Martínez

Heat assisted-forming processes are essential for Ti6Al4V sheet metal forming due to the poor formability of this alloy at room temperature. Although there exist works on the stress-strain response at high temperature, there is a lack of data in the literature on the yield criteria. The present paper presents an efficient experimental methodology to determine significant stress states at high temperature. Both plane strain data and compressive anisotropy values at high temperature allowed obtaining a more complete definition of the mechanical behavior of the Ti6Al4V, being the novel contribution of this research. Yield loci up to 900 °C were built according to different yield criteria that are fitted to the experimental data. Thus, Barlat1989 and CPB2006 were selected as the most suitable yield criteria to predict Ti6Al4V behavior. These criteria were extended to contemplate the anisotropy evolution under a wide range of working conditions. The formulated extended criteria for the entire range of conditions were close to the equivalent traditional ones applied to only a particular condition, which demonstrates the advanced made in the comprehensive modeling of Ti6Al4V alloy for all conditions applied in forming industries.