Search Results (24,070)

The hybridization of additive manufacturing (AM) with conventional manufacturing processes in tooling applications allows the customization of the tool. Examples include weight reduction, improving the vibration-dampening properties, or directing the coolant to the critical zones through intricate conformal cooling channels aimed at extending the tool life. In this regard, metallurgical challenges like the need for a post-processing heat treatment in the AM segment to meet the thermal and mechanical properties requirements persist. Heat treatment can destroy the dimensional accuracy of the pre-manufactured heat-treated wrought segment, on which the AM part is built. In the case of dissimilar joints, heat treatment may further impact the interface properties through the ease of diffusional reactions at elevated temperatures or buildup of residual stresses at the interface due to coefficient of thermal expansion (CTE) mismatch. In this communication, we report on the laser powder bed fusion (L-PBF) processing of MAR 60, a weldable carbon-free maraging powder, to manufacture a hybrid tool holder for general turning applications, comprising a wrought segment in 25CrMo4 low-alloy carbon-bearing tool steel. After L-PBF process optimization and manipulation, as-built (AB) MAR 60 steel was characterized with a hardness and tensile strength of ~450 HV (44–45 HRC) and >1400 MPa, respectively, matching those of pre-manufactured wrought 25CrMo4 (i.e., 42–45 HRC and 1400 MPa). The interface was defect-free with strong metallurgical bonding, showing slight microstructural and hardness variations, with a thickness of less than 400 µm. The matching strength and high Charpy V-notch impact energy (i.e., >40 J) of AB MAR 60 eliminate the necessity of any post-manufacturing heat treatment in the hybrid tool. Full article

Carbon fiber-reinforced epoxy composites, known for their high specific stiffness, specific strength, and toughness are one of the primary materials used for composite nozzles in aerospace industries. The high temperature vibration behaviors of the composite nozzles, especially those that withstand internal pressures, are key to affecting their dynamic response and even failure during the service. This study investigates the changes in frequencies and the vibrational modes of the carbon fiber reinforced epoxy nozzles, focusing on a three-dimensional (3D) orthogonal woven composite, with high internal temperatures from 25 °C to 300 °C and non-uniform internal pressures, up to 5.4 MPa. By considering the temperature-sensitive parameters, including Young’s modulus, thermal conductivity, and thermal expansion coefficients, which are derived from a self-built representative volume element (RVE), the intrinsic frequencies and vibrational modes in composite nozzles were examined. Findings reveal that 2 nodal diameter (ND) and 3ND modes are influenced by $E_{xx}$ and $E_{yy}$ while bending and torsion modes are predominantly affected by shear modulus. Temperature and internal pressure exhibit opposite effects on the modal frequencies. When the inner wall temperature rises from 25 °C to 300 °C, 2ND and 3ND frequencies decrease by an average of 30.39%, while bending and torsion frequencies decline by an average of 54.80%, primarily attributed to the decline modulus. Modal shifts were observed at ~150 °C, where the bending mode shifts to the 1st-order mode. More importantly, introducing non-uniform internal pressures induces the increase in nozzle stiffening in the xy-plane, leading to an apparent increase in the average 2ND and 3ND frequencies by 17.89% and 7.96%, while negligible changes in the bending and torsional frequencies. The temperature where the modal shifts were reduced to ~50 °C. The research performed in this work offers crucial insights for assessing the vibration life and safety design of hypersonic flight vehicles exposed to high-temperature thermal vibrations. Full article

China’s rapid economic growth has increased tensions between production, living, and ecological spaces (PLES), making sustainable land-use planning difficult. Therefore, PLES evolution and processes are a focus of current research. Remote sensing data with land-use transition matrices, centroid migration, standard deviation ellipses, spatial autocorrelation, and geographic detectors were used to study the dynamics of PLES in Hunan Province from 1990 to 2020, elucidate its mechanisms and main influencing factors, and provide a comprehensive understanding of its evolutionary characteristics. The main conclusions of our analysis are as follows: (1) Ecological space was the dominant land-use type, while production space increased, putting strain on natural areas. (2) Living space increased by 40.73% over three decades, mostly comprising manufacturing space, highlighting urban expansion. (3) Despite land-use changes, Loudi City’s PLES centroid remained central. (4) Standard deviation ellipses showed spatial shrinkage with directional stability, implying enhanced land usage within borders rather than outward growth. (5) The geographic detector analysis showed that the GDP, population density, slope, and elevation influenced these spatial changes. Economic prosperity drove urban expansion, but the slope and elevation limited development to accessible locations. These findings provide policymakers with essential information for balancing urbanization and ecological preservation and provide a case study for sustainable PLES design in rapidly developing regions. Full article

Open-pit mining often exposes weak rock layers, the strength of which significantly affects the stability of slopes. If these rock layers are also prone to disintegration and expansion, cyclic rainfall can exacerbate instability. Rainfall-induced changes in the seepage field also indirectly threaten the stability of slopes. Therefore, investigating the characteristics of mudstone limestone and the impact of the seepage field on slope instability under different wet–dry cycles is of great significance for the safe mining of open-pit mines. This paper takes the mudstone limestone slope of a certain open-pit mine in the southwest as the starting point and conducts experiments on saturated density, water absorption rate, permeability coefficient, compressive strength, and variable angle shear strength. Combined with scanning electron microscopy and phase analysis of X-ray diffraction analysis, the macroscopic and microscopic characteristics of the samples are comprehensively analyzed. FLAC3D software is used to explore the changes in the seepage field and the mechanism of instability. Our research found that for the preparation of mudstone limestone samples, a particle size of less than 1 mm and a drying temperature of 50 °C are optimal, with specific values for initial natural and saturated density, and natural water content. As the number of wet–dry cycles increases, the saturated density of mudstone limestone increases; the water absorption rate first rises sharply and then rises slowly; the permeability coefficient first rises sharply and then stabilizes, finally dropping sharply; the compressive and shear strength decreases slowly, and the internal friction angle changes little; frequent cycles also lead to mudification and seepage filtration. At the microscopic level, pores become larger and more regular, and the distribution is more concentrated; changes in mineral content weaken the strength. Combined with numerical simulation, the changes in the seepage field at the bottom of the slope exceed those at the slope surface and top, the transient saturated area expands, and the overall and local slope stability coefficients gradually decrease. During the third cycle, the local stability is lower than the overall stability, and the landslide trend shifts. In conclusion, wet–dry cycles change the pores and mineral content, affecting the physical and mechanical properties, leading to the deterioration of the transient saturated area, a decrease in matrix suction, and an increase in surface gravity, eventually causing slope instability. Full article

This study investigated the thermophysical properties of TWIP steel with respect to grain size. The coefficient of thermal expansion (β) of TWIP steel was approximately 22.4 × 10⁻⁶ °C⁻¹, and this value was hardly affected by the grain size. Therefore the density of TWIP steel was also unaffected by grain size within the tested range. The β in TWIP steel was higher than that of plain carbon steels (13–15 × 10⁻⁶ °C⁻¹) such as interstitial free (IF) steel and low-carbon steel, and stainless steels (18–21 × 10⁻⁶ °C⁻¹) such as X10NiCrMoTiB1515 steel and 18Cr-9Ni-2.95Cu-0.58Nb-0.1C steel. The specific heat capacity (c_p) increased with temperature because the major factor affecting c_p is the lattice vibrations. As the temperature increases, atomic vibrations become more active, allowing the material to store more thermal energy. Meanwhile, c_p slightly increased with increasing grain size since grain boundaries can suppress lattice vibrations and reduce the material’s ability to store thermal energy. The thermal conductivity (k) in TWIP steel gradually increased with temperature, consistent with the behavior observed in other high-alloy metals. k slightly increased with grain size, especially at lower temperatures, due to the increased grain boundary scattering of free electrons and phonons. This trend aligns with the Kapitza resistance model. While TWIP steel with refined grains exhibited higher yield and tensile strengths, this came with a decrease in total elongation and k. Thus, optimizing grain size to enhance both mechanical and thermal properties presents a challenge. The k in TWIP steel was substantially lower compared with that of plain carbon steels such as AISI 4340 steel, especially at low temperatures, due to its higher alloy content. At room temperature, the k of TWIP steels and plain carbon steels were approximately 13 W/m°C and 45 W/m°C, respectively. However, in higher temperature ranges where face centered cubic structures are predominant, the difference in k of the two steels became less pronounced. At 800 °C, for example, TWIP and plain carbon steels exhibited k values of approximately 24 W/m°C and 29 W/m°C, respectively. Full article

The rapid expansion of data has made global access easier, but it also demands increasing amounts of energy for data storage and processing. In response, neuromorphic electronics, inspired by the functionality of biological neurons and synapses, have emerged as a growing area of research. These devices enable in-memory computing, helping to overcome the “von Neumann bottleneck”, a limitation caused by the separation of memory and processing units in traditional von Neumann architecture. By leveraging multi-bit non-volatility, biologically inspired features, and Ohm’s law, synaptic devices show great potential for reducing energy consumption in multiplication and accumulation operations. Within the various non-volatile memory technologies available, flash memory stands out as a highly competitive option for storing large volumes of data. This review highlights recent advancements in neuromorphic computing that utilize NOR, AND, and NAND flash memory. This review also delves into the array architecture, operational methods, and electrical properties of NOR, AND, and NAND flash memory, emphasizing its application in different neural network designs. By providing a detailed overview of flash memory-based neuromorphic computing, this review offers valuable insights into optimizing its use across diverse applications. Full article

The expansion of the use of artificial intelligence (AI) across different stages of production and distribution in journalism is opening a debate on its applications within newsrooms and in business models. This research studies how different media outlets, media groups and institutions are beginning to create internal regulations for the use of AI, both from a technical and an ethical perspective. To do so, an international sample (N = 45) of editorial stylebooks and internal self-regulatory guidelines published between 2023 and early 2025 have been compiled—all links are openly available here—and put through a process of content analysis. The results indicate that the self-regulatory guidelines emerge from an individual initiative of the media themselves, with a focus on limiting the use of generative AI, particularly in text creation. The guidelines emphasize ethical commitments such as transparency, content verification, and respect for data and copyright while underlining the importance of human oversight. Key objectives include avoiding bias, ensuring information quality, and strengthening audience trust. Despite progress, regulation remains in its early stages and requires continuous adaptation to keep pace with technological advancements. Full article

This study proposes a novel cyclic stress path with simultaneous axial and confining stress and conducts triaxial testing on raw coal over various cycle periods. The analysis of bias stress–strain curves, deformation parameters, and energy indexes elucidated the mechanical and energy evolution patterns of coals under novel stress routes. The three deformation parameters can well reflect the deformation characteristics of the specimens. The last few cycles saw an increase in Poisson’s ratio and irreversible deformation, indicating that the coal samples were likely to crack. Specimens are more prone to instability and destruction due to increased expansion under high frequency loading. To explore the energy evolution, the energy percentage and damping ratio are added to the previously mentioned basic energy indexes. Faster cyclic period reduces specimen microstructure stability, increases mineral particle misalignment friction, and raises dissipated energy percentage and damping ratio. $D_S$ and $D_d$ based on deformation parameters and cumulative dissipated energy, respectively, can characterize the coal’s three damage stages of “deceleration–stabilization–acceleration”. Both damage variables accumulate faster in the acceleration damage stage due to cyclic period acceleration. Full article

As an important gateway for China’s foreign exchanges, the border areas of Guangxi face irrational land use issues that impact local ecology, the economy, national security, and international relations. With global attention on climate change, “carbon peaking”, “carbon neutrality”, and ecosystem carbon storage, this study focuses on the border area, using natural resource, socio-economic, and transportation factors. Through the PLUS and In VEST models, it predicts carbon storage under multiple scenarios. (1) The results show that from 2000 to 2020, forest land, water bodies, and other land types decreased, while construction land and cropland increased. Land use changes accelerated over time, with significant urban expansion into cropland and forest areas, reflecting rapid socio-economic development. (2) For 2030, the following projections were made: Under natural development, construction land expands significantly, forest land declines, and urbanization spreads outward. Under urban development, construction land grows fastest, forest and grassland decline sharply, and infrastructure reduces other land types. Under sustainable development, reductions in forest and grassland are mitigated, construction land grows moderately, and water bodies remain stable, achieving a balance between humans and nature. (3) Compared to 2020, ecosystem carbon storage declines across scenarios. Annual decreases are 513,223.13 tons (natural), 5,469,327.95 tons (urban), and 500,214.24 tons (sustainable). Sustainable development is crucial for achieving “dual carbon” goals. This study emphasizes ecological priority, strict cropland protection, and controlled construction land, offering sustainable land management strategies to ensure rational land use and border security. Full article

Desert encroachment significantly threatens the living and activity space of humanity, and undertaking human-directed vegetation restoration is one of the effective ways to prevent desert expansion. In the process of desert vegetation restoration, counting the number of tree saplings for rapidly assessing the survival rate of vegetation (such as Haloxylon ammodendron) is a critical task within the restoration process. However, traditional ground-based statistical methods are resource-intensive and time-consuming. This paper proposed a novel unsupervised fine segmentation framework driven by Grounding DINO prompt generation and optimization segment anything model, termed GDPGO-SAM, designed for the segmentation of desert vegetation from UAV-derived remote sensing imagery, thereby facilitating the rapid inventory of tree saplings counts. The framework combines the Grounding DINO object detector and the pre-trained visual model SAM, employing a task-prior-based prompt optimization mechanism to effectively capture the innate features of desert vegetation. This method achieves zero-sample instance segmentation of desert vegetation with an overall accuracy (OA) of 96.56%, a mean Intersection over Union (mIoU) of 81.50%, and a kappa coefficient (kappa) of 0.782, successfully overcoming the limitations of traditional supervised models that rely on passive memorization rather than true recognition. This research significantly enhances the precision of vegetation extraction and canopy depiction, providing strong support for the management of desert vegetation restoration and combating desert expansion. Full article

Renewable energy sources must be scheduled to manage power flow and load demand. Photovoltaic power generation is usually connected to power distribution networks and is not designed to add significant amounts of production in the event of increased electricity demand. Therefore, it is necessary to increase the generated capacity (i.e., hosting capacity) to meet the expansion in demand. This paper discussed two topics; the first is how to create an energy management strategy (EMS) for a hybrid micro-grid containing photovoltaic (PV) and battery energy storage system (BESS). A model was created within the MATLAB program through which the charging and discharging process of the BESS was managed, and the energy source was through PV. The model is connected to the leading network, where the m.file is linked to the model to control variable settings. This was carried out by using a logical–numerical modeling method. The second topic discussed how to evaluate hosting capacity (HC) without causing the network to collapse. This was achieved by choosing the best location and size for the PV. This study relied on the use of two algorithms, particle swarm optimization (PSO) and Harris hawks optimization (HHO). The fast decoupled load Flow (FDPF) method was adopted in the network analysis and finally the results of the two algorithms were compared. Full article

This research aims to identify effective strategies for reducing greenhouse gas emissions from agricultural waste. It employs a quantitative research approach using an advanced model, the Path Analysis—Generalized Method of Moments Based on a Nearest-Neighbor with Observed Variable Model (Path-GMM-Nearest-Neighbor Model). This model incorporates white noise and addresses gaps in previous models, ensuring minimal forecasting errors. The findings highlight the need for the government to implement the most suitable policy scenario to achieve sustained reductions in agricultural waste over the next two decades (2025–2044). Additionally, we found that the Path-GMM-Nearest-Neighbor Model demonstrated the highest performance, exhibiting the lowest Mean Absolute Percentage Error (MAPE) and Root Mean Squared Error (RMSE). Following in performance, in descending order, were the GM-ARIMA Model, Fuzzy Model, BP Model, ANN Model, and Regression Model. The optimal indices identified are green technology and biomass energy. Implementing these indices in national administration is projected to reduce agricultural waste growth to a rate of only 50.58% (2044/2025) while continuously decreasing greenhouse gas emissions, with an expansion rate limited to 43.68% (2044/2025). These measures ensure that emissions remain below Thailand’s carrying capacity threshold of 1560 Gg CO₂e. Thus, adopting this strategy as a national policy will enable Thailand to sustainably advance toward a green economy in the future. Full article

Addressing the urban–rural income disparity and fostering coordinated urban–rural development pose critical challenges for China in pursuit of its common prosperity strategy during its new phase of development. Regional integration emerges as a pivotal policy tool, which is extensively utilized to facilitate regional development coordination and significantly contributing to overall regional economic growth. This study delves into whether the implementation of regional integration policies generates a common prosperity effect, thereby reducing the disparity in income levels between urban and rural regions. Utilizing city-level panel data spanning from 2000 to 2019 within the Yangtze River Delta region, we treat the expansion of regional integration as a quasi-natural experiment and employ a time-varying Difference-in-Differences model to identify the integration’s common prosperity effect. Furthermore, we leverage mediation effect models to unravel the mechanisms through which integration influences the urban–rural divide in income. Our findings reveal that the expansion of integrated regions contributes to narrowing the urban–rural income gap with these results remaining robust across multiple tests. Urbanization and marketization are pivotal mechanisms driving the reduction in the urban–rural income disparity in integrated regions. Additionally, heterogeneity analysis uncovers significant spatial and temporal variations in the urban–rural income gap narrowing effect of integration expansion. Specifically, over time, the effect transitions from a significant negative impact to an insignificant positive one, while spatially, significant negative effects are observed in Jiangsu and Zhejiang provinces, contrasting with insignificant positive effects in Anhui province. This study offers fresh perspectives on the nexus between regional integration and the urban–rural income disparity, laying a scientific groundwork to evaluate the impacts of urban agglomeration integration and optimize policies aimed at fostering regional integration and coordinated urban–rural development. Full article

Dam construction facilitates the colonization of non-native fish species by altering the hydrological environment and increasing nutrient concentrations, while usually declining the richness of native fish species. The invasion of non-native fish species in subtropical reservoirs has become widespread in China; thus, research on the introduction of non-native fish species and their relationship with the environment remains urgently needed. In this study, we seasonally investigated fish communities across four reservoirs with different ages and nutrient levels in Fujian, China, examining the dominance, catch per unit effort (CPUE), and their relationships with environmental factors for native and non-native fish species. Two of the four reservoirs are 65 years old and the other two are six years old. We sampled a total of twenty-eight fish species, including six non-native species, and we found that each reservoir had non-native species, which became dominant species or important species in fish assemblage. However, the dominance and abundance of non-native species were higher in two high-nutrient-level reservoirs compared to the other two reservoirs. Both the native and non-native species’ CPUEs were positively correlated with total nitrogen concentrations and negatively correlated with water transparency. The CPUE of non-native fish species significantly increased with water depth. The CPUE of non-native species in old reservoirs was significantly lower than that in the young reservoirs. Our results suggested that a higher total nitrogen concentration and lower water depth promoted the population expansion of non-native species in subtropical reservoirs, and lower nutrient levels reduced the abundance of non-native species in those older reservoirs. Full article

This article reconsiders literature’s capacity to express and evoke spiritual experiences by turning to William James’s The Varieties of Religious Experience, especially his discussion of mysticism and his suggestion that poetry can bring about such states. James’s ideas are especially promising given recent developments in postsecular and postcritical scholarship that problematize a religious/secular divide and call into question a hermeneutics of suspicion. Bringing James into conversation with Paul Ricoeur, I aim to show how receptivity to spiritual experiences in literature might generate expansive models of both poetics and hermeneutics. To pursue these possibilities, my study analyzes three examples of Victorian lyric poems that probe the edges of wonder: Thomas Hardy’s “The Darkling Thrush”, Gerard Manley Hopkins’s “Nondum” and Dollie Radford’s “A Dream of ‘Dreams’”. These case studies strategically select work by writers of various belief or unbelief positions, highlighting the dynamism of the late nineteenth-century moment from which James’s writings emerged. I argue that this poetry facilitates a re-imagination of hope, beyond a faith/doubt dichotomy, as well as a re-framing of revelation, from proclamation to invitation. Building on insights from both James and Ricoeur, my discussion concludes by making the case for cultivating an interpretive disposition that does not guard against but opens toward poetry’s latent potential to take readers by surprise. Full article