Search

Satellite-derived Land Surface Temperature (LST) plays an important role in research on natural energy balance and water cycle. Considering the tradeoff between spatial and temporal resolutions, accurate fine-resolution LST must be obtained through the use of LST downscaling (DLST) technology. Various methods have been proposed for DLST at fine resolutions (e.g., 10 m) and small scales. However, the scale effect of these methods, which is inherent to DLST processes at different extents, has rarely been addressed, thus limiting their application. In this study, a modified daily 10 m resolution DLST method based on Google Earth Engine, called mDTSG, is proposed in order to reduce the scale effect at fine spatial resolutions. The proposed method introduces a convolution-based moving window into the DLST process for the fusion of different remote sensing data. The performance of the modified method is compared with the original method in six regions characterized by various extents and landscape heterogeneity. The results show that the scale effect is significant in the DLST process at fine resolutions across extents ranging from 100 km2 to 22,500 km2. Compared with the original method, mDTSG can effectively reduce the LST value differences between tile edges, especially when considering large extents (>22,500 km2) with an average R 2 improvement of 33.75%. The average M A E is 1.63 °C, and the average R M S E is 2.3 °C in the mDTSG results, when compared with independent remote sensing products across the six regions. A comparison with in situ observations also shows promising results, with an M A E of 2.03 °C and an R M S E of 2.63 °C. These findings highlight the robustness and scalability of the mDTSG method, making it a valuable tool for fine-resolution LST applications in diverse and extensive landscapes. [ABSTRACT FROM AUTHOR]

In the modified formula for the cubic law, the roughness correction coefficient C serves as a parameter that indicates the characteristics of the roughness of a rock's surface. In this study, surface data for natural rock samples were acquired through high-precision 3D scanning and combined with publicly accessible CT scan data on rough rock fractures to generate spatial coordinates. The roughness correction coefficient C was calculated and analyzed using both formulaic and numerical methods. The analysis revealed significant effects of scale on the roughness correction coefficient for rock fractures within a size range of 5 to 10 cm (determined based on the actual sample size), with tensile fractures demonstrating greater variations compared to shear fractures. When calculating the roughness correction coefficient on the same fracture surface in different directions, significant directional effects were observed. Furthermore, elliptical fitting demonstrated favorable results. The conclusion drawn was that the roughness correction coefficient for fracture surfaces can be represented effectively using a tensor form, thereby simplifying the expression of directionality. Calculating and analyzing the fractal dimension of a rough surface further confirmed the existence of effects of size on roughness. [ABSTRACT FROM AUTHOR]

The objective of this research is to explore the scale effect on the mechanical properties of sheet‐based triply periodic minimal surface (TPMS) uniform lattice structures fabricated with PLA (polylactic acid) under quasi‐static loading conditions. The scale dependency was evaluated by two additional breakdown categories, namely, wall thickness effect and unit cell size effect. Deformation mechanisms and failure modes as well as mechanical properties including stiffness, yield strength, first peak stress, and energy absorption based on the categories of wall thickness, unit cell size, and scale were evaluated experimentally. The assessment of the scale effect involved considering the combined influence of wall thickness and unit cell size. In addition, numerical analysis was also performed to investigate the stress distributions and compare with the experimental results for certain geometries. Ultimately, the relation between the normalized mechanical properties and relative density is evaluated and categorized, which can be used as an indication for future design practices. Highlights: Scale, wall thickness, and unit cell size effect of lattice structures were studied.Relative density played a significant role in determining mechanical properties.Unit cell size to wall thickness ratio is critical for different failure mechanisms.Normalized mechanical properties were evaluated for the future design. [ABSTRACT FROM AUTHOR]

Nonpoint source (NPS) pollution has emerged as the predominant water environment issue confronting plateau lakes in central Yunnan. Quantitative analysis of the impact of NPS pollution on water quality constitutes the key to preventing and controlling water pollution. However, currently, there is a dearth of research on identifying NPS pollution risks and exploring their relationship with water quality based on the Minimum Cumulative Resistance (MCR) model in the plateau lake basins of central Yunnan. Particularly, studies on the spatial heterogeneity of the impact of NPS pollution on water quality from a multi-scale perspective are scarce. Therefore, this study focuses on three typical lake basins in the Central Yunnan Plateau–Fuxian Lake, Xingyun Lake, and Qilu Lake (the Three Lakes). Utilizing the MCR model to identify NPS pollution risks, the study analyzes seven different scales, including sub-basins, riparian buffer zones (100 m, 300 m, 500 m, 700 m, and 1,000 m) and lakeshore zones, to reveal the multi-scale effects of NPS pollution on water quality through correlation analysis. The results indicate that: (1) Over 60% of the areas in the Three Lakes Basin are at high or extremely high risk, mainly concentrated in flat terrain and around inflow rivers; (2) The area of NPS pollution from paddy field source landscape (PFSL) is greater than that from construction land source landscape (CLSL), and the high-risk areas of NPS pollution are also larger for PFSL compared to CLSL; (3) The mean resistance values of PFSL and CLSL show a significant negative correlation with monthly mean values of water quality indexes (NH3-N, TP, CODCr), with the 1,000 m riparian buffer zone scale showing the greatest correlation with most water quality indexes, especially NH3-N; (4) The correlation between the mean resistance value of CLSL and the monthly mean values of water quality indexes is significantly higher than that of PFSL, indicating a greater impact of CLSL on water quality compared to PFSL. In summary, PFSL and CLSL are the primary sources of NPS pollution in the Three Lakes Basins. The 1,000 m riparian buffer zone scale is the most sensitive to the impact of NPS pollution on water quality. This study provides scientific references for landscape pattern optimization and precise control of NPS pollution risks in the Central Yunnan Plateau lake basins and offers a new research perspective for exploring multi-scale effects of NPS pollution on water quality. [ABSTRACT FROM AUTHOR]

Urban forests are expected to mitigate the urban heat island (UHI) effect in megacities. The mechanism and factors influencing the cooling effect of urban forest have been extensively discussed; however, the spatial scale effect of cooling heterogeneity of the urban forest is still uncertain. Based on Landsat 8/9 OLI/TIRS imagery, the relationship between land surface temperature (LST) and the spatial patterns of forest vegetation in Beijing, Shanghai, and Tianjin was investigated at different spatial scales, including patch level, rural–urban gradient, and multiple spatial extents. The results indicated that the cooling effect of forest vegetation is stronger than that of grassland. The combination of the three indicators—Area, Normalized Difference Vegetation Index (NDVI), and the percentage of neighboring greenspace (NGP)—can largely explain the differences in cooling intensity between forest vegetation patches. The results suggest that the cooling effect of forest vegetation was affected by air humidity, and the cooling intensity of forest vegetation is stronger in coastal cities than in inland cities. In dry cities, the impact of the patch area on the cooling intensity of forest patches is greater than the NDVI, while the opposite is true in humid coastal cities. The LST variations in the urban–rural gradient can largely be explained by the landscape composition. This study proposes to apply larger spatial extents (e.g., 450 m × 450 m grid in this study) to investigate the relationship between landscape configuration metrics (e.g., Aggregation and Cohesion in this study) and the LST; and to use smaller spatial extents (e.g., 90 m × 90 m grid in this study) to reveal the relationship between area and shape related metrics. This study extends our scientific understanding of scaling effects to the relationship between landscape metrics and the LST. [ABSTRACT FROM AUTHOR]

To address the challenges posed by the living environment and promote sustainable development, the Chinese government implemented a new environmental protection law in 2015. Based on the provincial panel data of 30 provinces, autonomous regions, and municipalities in China from 2010 to 2019, the spatial Durbin model is used to investigate the impact of environmental regulation on the employment effect of high-tech industries, and the spatial effect decomposition is used to further clarify the specific impact of environmental regulation on the employment of high-tech industries. The research finds that: Firstly, at the present stage, environmental regulation in China remains at a relatively low level. The employment generation effect of environmental regulation on high-tech industries is insufficient to offset the employment loss effect. Strengthening environmental regulation in the short term is unfavorable for employment in high-tech industries. Secondly, adjacent regions adopt a strategy of competitive differential environmental regulation between governments. The local government relaxes environmental regulation to increase employment, while the neighboring government strengthens environmental regulation to promote industrial upgrading. This approach benefits local employment in high-tech industries in the short term but hinders the sustainable development of high-tech industries. Thirdly, environmental regulation exhibits significant negative spatial spillover effects. Strengthening local environmental regulation will suppress the growth of high-tech industry employment in neighboring areas, and the spatial spillover effect of environmental regulation is primarily influenced by geographic location. [ABSTRACT FROM AUTHOR]

A thorough exploration of Ecosystem Services (ESs) and their intricate interactions across time and space is a prerequisite for the sustainable management of multiple ESs. This study aimed to systematically evaluate the ESs of the middle reaches of the Yangtze River Urban Agglomeration (MRYRUA) across multiple spatial and temporal scales, thereby enhancing ecosystem management and informed scientific decision-making. Specifically, this study employed the InVEST model, hot spot analysis, a geographically weighted regression model, and self-organizing feature mapping combined with K-means clustering to systematically quantify the spatiotemporal characteristics, trade-offs, synergies, and ecosystem service clusters of habitat quality (HQ), water yield (WY), carbon storage (CS), soil conservation (SC), and landscape aesthetics (LA) at grid and county scales from 2000 to 2020. The results revealed the following: (1) There was significant spatial heterogeneity among various ESs, with an overall spatial pattern exhibiting layered and interwoven variations. (2) Trade-offs predominantly characterized the relationships among ESs in the MRYRUA, with the absolute values of correlation coefficients mostly reaching their nadir in 2010. The interaction strengths between HQ and CS, and between CS and SC, increased with scale, while the relationships and strengths between LA and other ESs were less affected by scale changes. (3) At the grid scale, five types of ecosystem service bundles (ESBs) were identified, whereas at the district scale, four types of ESBs were delineated, including three common types: the WY–LA synergy bundle, Ecological transition bundle, and Key synergetic bundle, and three distinct types: the HQ–CS synergy bundle, Integrated ecological bundle, and Key synergetic bundle. The transitions of these ESBs over the 20 year period generally exhibited fluctuating evolutionary characteristics, with more pronounced fluctuations as the scale expanded. The results improve our comprehension of how ESs are related across various scales and provide theoretical and scientific references for multi-scale sustainable ecosystem zoning management and ecological environment governance. [ABSTRACT FROM AUTHOR]

Accurate spatial distribution of carbon dioxide (CO2) emissions is essential information needed to peaking emissions and achieving carbon neutral in China. The aim of this study was to map CO2 emissions with high spatial resolution at provincial scale and then explore the scale effect on mapping results. As an example, the spatiotemporal pattern and factors influencing CO2 emissions were examined in Guizhou Province in Western China. With the proposed method, a reasonable spatial distribution of CO2 emissions with high spatial resolution was obtained, which had relatively accurate information on spatial details. The optimal resolution of CO2 emissions at the provincial scale under high spatial resolution was approximately 90 m and 1260 m. More detailed grid data can better reflect the spatial variability of CO2 emissions. Emissions of CO2 were spatially heterogeneous in Guizhou, with high emissions in centers of big cities that gradually spread and decreased from city centers. From 2009 to 2019, the spatial distribution of CO2 emissions developed from agglomeration to dispersion. Areas of high carbon emissions decreased, those of medium carbon emissions increased, and many areas changed from no emissions to carbon emissions. Industrial land had the highest emissions, followed by commercial and transportation lands. Over 10 years, changes occurred in the relation between interregional economic level of Guizhou and CO2 emissions, with the relation changing from linear into an inverted U-shaped relation. The effect of industrial structure on CO2 emissions decreased, and the linear increase between CO2 emissions and the urban scale became more evident. The results of this study will contribute to accurate monitoring and management of carbon emissions in Guizhou, as well as provide support to formulate policies related to controls on carbon emissions in different regions. [ABSTRACT FROM AUTHOR]

Abstract Accurate spatial distribution of carbon dioxide (CO2) emissions is essential information needed to peaking emissions and achieving carbon neutral in China. The aim of this study was to map CO2 emissions with high spatial resolution at provincial scale and then explore the scale effect on mapping results. As an example, the spatiotemporal pattern and factors influencing CO2 emissions were examined in Guizhou Province in Western China. With the proposed method, a reasonable spatial distribution of CO2 emissions with high spatial resolution was obtained, which had relatively accurate information on spatial details. The optimal resolution of CO2 emissions at the provincial scale under high spatial resolution was approximately 90 m and 1260 m. More detailed grid data can better reflect the spatial variability of CO2 emissions. Emissions of CO2 were spatially heterogeneous in Guizhou, with high emissions in centers of big cities that gradually spread and decreased from city centers. From 2009 to 2019, the spatial distribution of CO2 emissions developed from agglomeration to dispersion. Areas of high carbon emissions decreased, those of medium carbon emissions increased, and many areas changed from no emissions to carbon emissions. Industrial land had the highest emissions, followed by commercial and transportation lands. Over 10 years, changes occurred in the relation between interregional economic level of Guizhou and CO2 emissions, with the relation changing from linear into an inverted U-shaped relation. The effect of industrial structure on CO2 emissions decreased, and the linear increase between CO2 emissions and the urban scale became more evident. The results of this study will contribute to accurate monitoring and management of carbon emissions in Guizhou, as well as provide support to formulate policies related to controls on carbon emissions in different regions.

The technology of pantograph sinking in the cavity is generally adopted in the new generation of high-speed trains in China for aerodynamic noise reduction in this region. This study takes a high-speed train with a 4-car formation and a pantograph as the research object and compares the aerodynamic acoustic performance of two scale models, 1/8 and 1/1, using large eddy simulation and Ffowcs Williams–Hawkings integral equation. It is found that there is no direct scale similarity between their aeroacoustic performance. The 1/1 model airflow is separated at the leading edge of the panhead and reattached to the panhead, and its vortex shedding Strouhal number (St) is 0.17. However, the 1/8 model airflow is separated directly at the leading edge of the panhead, and its St is 0.13. The cavity's vortex shedding frequency is in agreement with that calculated by the Rooster empirical formula. The two scale models exhibit some similar characteristics in distribution of sound source energy, but the energy distribution of the 1/8 model is more concentrated in the middle and lower regions. The contribution rates of their middle and lower regions to the radiated noise in the two models are 27.3% and 87.2%, respectively. The peak frequencies of the radiated noise from the 1/1 model are 307 and 571 Hz. The 307 Hz is consistent with the frequency of panhead vortex shedding, and the 571 Hz is more likely to be the result of the superposition of various components. In contrast, the peak frequencies of the radiated noise from the 1/8 scale model are 280 and 1970 Hz. The 280 Hz comes from the shear layer oscillation between the cavity and the bottom frame, and the 1970 Hz is close to the frequency at which the panhead vortex sheds. This shows that the scaled model results need to be corrected before applying to the full-scale model. [ABSTRACT FROM AUTHOR]

[Objective] Carbon capture, utilization, and storage (CCUS) technology is a core tool for reducing emissions and carbon output in coal-fired power plants and is considered key to achieving the carbon neutrality goals. However, in China, the economic returns on investment in CCUS are low, the overall benefits are uncertain and difficult to measure, and CCUS is still in the demonstration phase. Accurately forecasting the benefits of CCUS investment is of critical scientific significance for clarifying technological pathways, optimizing resource allocation, and promoting its commercialization. [Methods] This study took coal-fired power plants as the research subject and employed the system dynamics method to predict the comprehensive benefits of CCUS investment in Chinese coal-fired power plants from four dimensions: economic development, electric energy, environmental emission reduction, and social security. [Results] (1) The study found that after coal-fired power plants were equipped with CCUS technology, the comprehensive benefits of CCUS investment experienced a change from low-level stagnation to fluctuating increases, and then rapid growth. (2) Driven by technological progress and economies of scale, the benefits of CCUS investment have significantly increased. Technological progress has improved capture efficiency and reduced costs, while economies of scale have enhanced economic, environmental, and social benefits through increased installed capacity and improved carbon reduction efficiency, greatly improving overall investment returns.(3) Government subsidies, carbon taxes, and carbon trading prices all significantly enhance the benefits of CCUS investment. Among them, the carbon trading mechanism has the most notable impact on economic benefits and environmental reduction, while the carbon taxes,by increasing power generation costs, not only indirectly motivates enterprises to implement CCUS technology upgrades but also further improves overall investment efficiency. [Conclusion] In the process of commercial deployment and comprehensive benefit improvement of CCUS, the cost reduction brought by the iteration and scale of CCUS itself plays a core role. Compared with policy support measures such as subsidies, the carbon market trading mechanism plays a greater incentive role in the development of CCUS. Based on this, China should strengthen CCUS technology research, promote the inclusion of CCUS projects in the carbon trading mechanism as soon as possible, and formulate a moderate subsidy incentive policy for CCUS to increase the benefits of CCUS investment and help achieve the carbon neutrality goals.

Abstract The technology of pantograph sinking in the cavity is generally adopted in the new generation of high-speed trains in China for aerodynamic noise reduction in this region. This study takes a high-speed train with a 4-car formation and a pantograph as the research object and compares the aerodynamic acoustic performance of two scale models, 1/8 and 1/1, using large eddy simulation and Ffowcs Williams–Hawkings integral equation. It is found that there is no direct scale similarity between their aeroacoustic performance. The 1/1 model airflow is separated at the leading edge of the panhead and reattached to the panhead, and its vortex shedding Strouhal number (St) is 0.17. However, the 1/8 model airflow is separated directly at the leading edge of the panhead, and its St is 0.13. The cavity’s vortex shedding frequency is in agreement with that calculated by the Rooster empirical formula. The two scale models exhibit some similar characteristics in distribution of sound source energy, but the energy distribution of the 1/8 model is more concentrated in the middle and lower regions. The contribution rates of their middle and lower regions to the radiated noise in the two models are 27.3% and 87.2%, respectively. The peak frequencies of the radiated noise from the 1/1 model are 307 and 571 Hz. The 307 Hz is consistent with the frequency of panhead vortex shedding, and the 571 Hz is more likely to be the result of the superposition of various components. In contrast, the peak frequencies of the radiated noise from the 1/8 scale model are 280 and 1970 Hz. The 280 Hz comes from the shear layer oscillation between the cavity and the bottom frame, and the 1970 Hz is close to the frequency at which the panhead vortex sheds. This shows that the scaled model results need to be corrected before applying to the full-scale model.

Abstract Having an accurate understanding of the scale effect of surface morphology characteristics is crucial to examining the mechanical behavior of rock structural plane. At present, the quantification and sampling methods of surface morphology show diversity, which is the potential reason for the inconsistent research conclusions on scale effect. Firstly, based on mathematical statistics and correlation analysis, the most representative parameter is proposed from hundreds of morphological parameters. Then, the previous scale effect sampling methods are analyzed. In order to ensure that the selected samples are representative, a novel sampling method, considering all morphological information, is proposed. By means of the novel quantification and sampling methods, the size effect characteristics are systematically analyzed. Under the conditions of different rock types, shear directions and sampling locations, etc., discontinuity roughness does not change significantly with sampling scale. As sampling scale increases, the distribution range of representative samples is gradually concentrated, the total amount decreases, and the proportion increases. However, the distribution of representative samples on the initial structural plane does not show obvious regularity. These findings would provide theoretical support for the deformation control and stability analysis of rock mass in engineering.

Many existing efforts have taken advantage of large-scale spatial-temporal data to partition cities via constructed human interaction networks. However, few studies focus on communities emerging between adjacent cities in big urban agglomerations, which we call “cross-city” communities. In this study, we introduce a novel framework to detect cross-city communities in urban agglomerations under different scales leveraging a large number of fine-grained mobile signaling data aiming to break the original administrative boundaries. Taking the Pearl River Delta (PRD) urban agglomeration in China as study area, we investigate the existence of potential communities at three scales, i.e. city-group level, city level and sub-city level. The partition results are expected to benefit transportation planning, urban zoning and administrative boundary re-delineation. The results from our study highlight the necessity of considering cross-city communities and their scale effects when examining urban spatial interactions.

This paper presents an investigation of the scale effect on the flow around a propeller using the CFD method. The differences in the numerical setup and the results obtained for the characteristics of an open water propeller are described and analysed in this paper. Moreover, the paper also highlight and analyse the scale effect on differences in flow around the propeller, such as the pressure fields in the cross section, the distributions of the skin friction coefficient and limiting streamlines on the propeller blade, the vortices in the wake of the propeller, and the velocity fields. The differences in the flow around the propeller are more clearly seen when it works under heavy loading conditions, an important finding that can support designers in improving propeller performance, investigating cavitations, etc. at the full scale. The reference propeller used in this study is the benchmark propeller PPTC VP 1304.

Heterogeneous karst surfaces exerted scaling effects whereby specific runoff decrease with increasing area. The existing RUSLE-L equations are limited by the default implicit assumption that the surface-runoff intensity is constant at any slope length. The objective of this study was to modify the L-equation by establishing the functional relationship between surface-runoff intensity and karst slope length, and to evaluate its predictive capability at different resolution DEMs. Transfer grid layers were generated based on the area rate of surface karstification and considered the runoff transmission percentage at the exposed karst fractures or conduits to be zero. Using the multiple flow direction algorithm united with the transfer grid (MFDTG), the flow accumulation of each grid cell was simulated to estimate the average surface-runoff intensity over different slope lengths. The effectiveness of MFDTG algorithm was validated by runoff plot data in Southwestern China. The simulated results in a typical peak-cluster depression basin with an area rate of surface karstification of 6.5% showed that the relationship between surface-runoff intensity and slope length was a negative power function. Estimated by the proposed modified L-equation ((alx(b+1)/22.13)m), the L-factor averages of the study basin ranged from 0.35 to 0.41 at 1, 5, 25 and 90 m resolutions respectively. This study indicated that the modified L-equation enables an improved prediction of the much smaller L-factor and the use of any resolution DEMs on karst landscapes. Particular attention should be given to the variation of surface-runoff intensity with slope length when predicting L-factor on hillslopes with runoff scale effect.

In this paper, the development of a 3D adaptive probabilistic explicit cracking model for concrete is reported. The contribution offered herein consists in a new adaptive mesh strategy designed to optimize the use of interface elements in probabilistic explicit cracking models. The proposed adaptive mesh procedure is markedly different from other strategies found in the literature, since it takes into account possible influences on the redistribution of stresses after cracking and can also be applied to purely deterministic cracking models. The process of obtaining the most appropriate adaptive mesh procedure involved the development and evaluation of three different adaptivity strategies. Two of these adaptivity strategies were shown to be inappropriate due to issues related to stress redistribution after cracking. The validation results demonstrate that the developed adaptive probabilistic model is capable of predicting the scale effect at a level similar to that experimentally observed, considering the tensile failure of plain concrete specimens. The results also show that different softening levels can be obtained. The proposed adaptive mesh strategy proved to be advantageous, being able to promote significant reductions in the simulation time in comparison with the classical strategy commonly used in probabilistic explicit cracking models. [ABSTRACT FROM AUTHOR]

[Objective] The aims of this study are to explore the scale effect in the process of runoff and sediment movement on the slope, to clarify the scale effect influence mechanism of runoff and sediment movement in the hilly and gully region of the Loess Plateau, so as to provide scientific support for the study of runoff and sediment transfer mechanism and the comprehensive management of runoff and sediment in the Yellow River Basin. [Methods] Based on the runoff and sediment data of four runoff fields in Zizhou runoff test station of the Yellow River, the scale transfer effect of runoff and sediment yield on slope was revealed by comparing and analyzing the runoff and sediment yield processes of different slope lengths under rainfall events. The concept of scale transfer efficiency was proposed to characterize the runoff and sediment transfer relationship between the upper and lower levels, and to further explore the influencing factors on runoff and sediment transfer efficiency. [Results] (1) The characteristics of different rainfall types had different effects on the runoff and sediment yield on the slope. The rainfall duration mainly affected the runoff and sediment yield on the slope, and the average rainfall intensity mainly affected the starting time of runoff and sediment yield on the slope. (2) Under the event of rainfall, the runoff transfer of different slope lengths was an ideal equilibrium transfer mechanism, and with the increase of slope length, the transfer capacity of runoff showed a decreasing trend. Under the condition of 40~60m slope length, the transfer of sediment was a non- equilibrium transfer process. With the increase of slope length, the transfer capacity of sediment increased first and then decreased. (3) The influencing factors on flow-sediment transfer efficiency on different scale slopes were different. Runoff depth, average rainfall intensity and surface soil moisture content after rain were the main factors affecting the transfer efficiency of flow-sediment scale. [Conclusion] The runoff and sediment yield capacity of the slope in the loess hilly and gully region is affected by rainfall characteristics and slope length. There is a significant scale effect of damage or gain in the transmission of runoff and sediment along the way. The efficiency of water and sediment transport is regulated by multiple factors such as rainfall intensity, runoff and soil moisture. [ABSTRACT FROM AUTHOR]

Many existing efforts have taken advantage of large-scale spatial-temporal data to partition cities via constructed human interaction networks. However, few studies focus on communities emerging between adjacent cities in big urban agglomerations, which we call "cross-city" communities. In this study, we introduce a novel framework to detect cross-city communities in urban agglomerations under different scales leveraging a large number of fine-grained mobile signaling data aiming to break the original administrative boundaries. Taking the Pearl River Delta (PRD) urban agglomeration in China as study area, we investigate the existence of potential communities at three scales, i.e. city-group level, city level and sub-city level. The partition results are expected to benefit transportation planning, urban zoning and administrative boundary re-delineation. The results from our study highlight the necessity of considering cross-city communities and their scale effects when examining urban spatial interactions. [ABSTRACT FROM AUTHOR]

Preventing eutrophication requires a deep understanding of nutrient sources and migration processes. The Guanshan River in the Danjiangkou Reservoir was selected as a typical agricultural basin. River water, sediment, and soil samples were collected to determine nitrogen (N) and phosphorus (P) contents and forms. Multivariate statistical analysis, buffer analysis, and extreme gradient boosting regression (XGBoost) were used to investigate the nutrient sources, the sources' scale effects, and migration. The results showed that the exogenous sources of river nutrients were fertilizer (provided phosphate (PO4-P) and ammonium (NH4-N)), domestic wastewater (provided nitrate (NO3-N) and organic nitrogen), and natural soil and rock leaching (provided PO4-P and organic phosphorus). Fertilization within 300–1200 m and domestic wastewater discharge within 150 m of the river affected the contents of the river nutrients significantly (with R ranging between 0.40 and 0.73, p ≤ 0.01). The sediment was the N source and P sink of the overlying water. With NH4-N/PO4-P compound fertilization, the NO3-N and calcium-bound phosphorus (Ca-P) exhibited co-enrichment. Appropriately increasing NH4-N application could stimulate P biological uptake, thus inhibiting P emigration from agricultural soil under N-limited states. In conclusion, this study effectively recognized river nutrient sources and their scale impacts and also explored more effective fertilization strategies, which are beneficial for the optimized management of agricultural activities. [ABSTRACT FROM AUTHOR]

Thinning is a crucial approach to the near-natural conversion of plantations, contributing to the sustainability of forest management. However, over a rotation, the effects of thinning on tree growth, structure, and species diversity, as well as their scale-dependent outcomes, remain unclear. Ten years after conducting individual tree thinning in a Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) monoculture in southwest China, we analyzed the thinning effects within the influence zone (r = 0–2.5 m) centered around stumps and center trees. The results indicate that (1) individual tree thinning did not significantly promote the increment of diameter at breast height, volume, and biomass of Chinese fir. The four nearest Chinese fir around stumps and center trees were in a state of random distribution, high mixing, and dominance; (2) individual tree thinning significantly promoted the formation of species abundance and richness at r = 2–2.5 m. With increased scale, more species were found, leading to increased stability in diameter and species distribution. Linear and nonlinear relationships between diameter classes, mingling, and dominance became more stable; (3) later-coming populations within both modes exhibited a common characteristic of random distribution, high mixing, and disadvantage at each scale, but with significant differences in species composition (kj = 0.22–0.61). These results suggest that individual tree thinning has limited impacts on the growth and structure of retained trees in Chinese fir plantations but significantly enhances the formation of species diversity, demonstrating scale effects. This underscores the feasibility of individual tree thinning in the near-natural conversion of plantations. [ABSTRACT FROM AUTHOR]

Topographic scale characteristics contain valuable information for interpreting landform structures, which is crucial for understanding the spatial differentiation of landforms across large areas. However, the absence of parameters that specifically describe the topographic scale characteristics hinders the quantitative representation of regional topography from the perspective of spatial scales. In this study, false-color composite images were generated using normalized topographic relief data, showing a type of scale-oriented terrain pattern. Subsequent analysis indicated a direct correlation between the luminance of the patterns and the normalized topographic relief. Additionally, a linear correlation exists between the color of the patterns and the change rate in normalized topographic relief. Based on the analysis results, the issue of characterizing topographic scale effects was transformed into a problem of interpreting terrain patterns. The introduction of two parameters, flux and curl of topographic field, allowed for the interpretation of the terrain patterns. The assessment indicated that the calculated values of topographic field flux are equivalent to the luminance of the terrain patterns and the variations in the topographic field curl correspond with the spatial differentiation of colors in the terrain patterns. This study introduced a new approach to analyzing topographic scale characteristics, providing a pathway for quantitatively describing scale effects and automatically classifying landforms at a regional scale. Through exploratory analysis on artificially constructed simple DEMs and verification in four typical geomorphological regions of real terrain, it was shown that the terrain pattern method has better intuitiveness than the scale signature approach. It can reflect the scale characteristics of terrain in continuous space. Compared to the MTPCC image, the terrain parameters derived from the terrain pattern method further quantitatively describe the scale effects of the terrain. [ABSTRACT FROM AUTHOR]

Understanding the scale effect of relationships among ecosystem services (ESs) and the factors influencing these relationships, is vital for sustainable management of ESs. Previous research has focused less on multiple scale units, and the driving mechanisms behind ESs interactions remain unclear. Therefore, in this study, we assessed the spatial distribution of water yield (WY), water purification (WP), and soil conservation (SC) across four spatial scales (3 km × 3 km grid, 5 km × 5 km grid, sub-watershed, and county scales) in the Lishui River Basin of China during 2020. Using the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model, geographical weighted regression, and Pearson correlation analysis, we examined tradeoffs and synergies among these ESs at various scales. Additionally, we employed a geographic detector to analyze the reactions and scale effects among these tradeoffs/synergies and social-ecological factors. Our findings revealed the following: (1) Significant spatial heterogeneity in ESs was observed in the basin. The WY decreased from west (2511.65 mm) to east (890.06 mm), with high WP values concentrated in the eastern part, and high SC values (8.30 × 105 t/hm2) found in densely forested and grassland areas surrounding water bodies. Forested and cultivated lands were key contributors to ESs in the basin. (2) Across the four investigated scales, tradeoffs or synergies between the same ESs becoming more pronounced as the scale increased. Notably, most ES relationships displayed their strongest synergies at the county scale, with certain spatial areas demonstrating change in interaction directions. (3) The explanatory power of single- or double-factor interactions increased with scale. ESs interactions were found to be closely linked to climatic factors, as well as topographic features (including slope gradient and elevation), with precipitation exhibiting relatively high explanatory power. The interaction of natural and social factors significantly outweighed the combined interaction of dual social factors. This indicated that socio-ecological factors, especially climate and topography, jointly influenced the intensity and direction of ES tradeoffs/synergies. Scale effects arose from the “peak cutting and valley filling” phenomenon during scale transitions. These insights hold significant value for guiding hierarchical management strategies for regional ESs and informing decisions regarding resource allocation.

Nonpoint source (NPS) pollution has emerged as the predominant water environment issue confronting plateau lakes in central Yunnan. Quantitative analysis of the impact of NPS pollution on water quality constitutes the key to preventing and controlling water pollution. However, currently, there is a dearth of research on identifying NPS pollution risks and exploring their relationship with water quality based on the Minimum Cumulative Resistance (MCR) model in the plateau lake basins of central Yunnan. Particularly, studies on the spatial heterogeneity of the impact of NPS pollution on water quality from a multi-scale perspective are scarce. Therefore, this study focuses on three typical lake basins in the Central Yunnan Plateau–Fuxian Lake, Xingyun Lake, and Qilu Lake (the Three Lakes). Utilizing the MCR model to identify NPS pollution risks, the study analyzes seven different scales, including sub-basins, riparian buffer zones (100 m, 300 m, 500 m, 700 m, and 1,000 m) and lakeshore zones, to reveal the multi-scale effects of NPS pollution on water quality through correlation analysis. The results indicate that: (1) Over 60% of the areas in the Three Lakes Basin are at high or extremely high risk, mainly concentrated in flat terrain and around inflow rivers; (2) The area of NPS pollution from paddy field source landscape (PFSL) is greater than that from construction land source landscape (CLSL), and the high-risk areas of NPS pollution are also larger for PFSL compared to CLSL; (3) The mean resistance values of PFSL and CLSL show a significant negative correlation with monthly mean values of water quality indexes (NH3-N, TP, CODCr), with the 1,000 m riparian buffer zone scale showing the greatest correlation with most water quality indexes, especially NH3-N; (4) The correlation between the mean resistance value of CLSL and the monthly mean values of water quality indexes is significantly higher than that of PFSL, indicating a greater impact of CLSL on water quality compared to PFSL. In summary, PFSL and CLSL are the primary sources of NPS pollution in the Three Lakes Basins. The 1,000 m riparian buffer zone scale is the most sensitive to the impact of NPS pollution on water quality. This study provides scientific references for landscape pattern optimization and precise control of NPS pollution risks in the Central Yunnan Plateau lake basins and offers a new research perspective for exploring multi-scale effects of NPS pollution on water quality.

An improved understanding of tunnel fire dynamics is crucial for fire and life safety. This work highlights the significance of Computational Fluid Dynamics (CFD) techniques in addressing the interaction between tunnel fires and rainfall. The discrete phase model based on the Lagrangian approach is applied to simulate raindrops, while the species transport model is used to simulate fuel combustion. A numerical model is established to investigate the impact of rainfall on tunnel fires, and the correctness of the model is verified by comparing the results to model-scale tunnel experiments. Results show that the raindrops increase the local pressure in the rainfall area, creating a pressure difference between the rainfall tunnel portal and the no-rain portal, which leads to longitudinal airflow inside the tunnel. This rain-induced airflow prevents smoke from moving toward the rainfall tunnel portal and decreases the smoke height near the no-rainfall portal. Correlations between the local increased pressure, induced-airflow velocity, and rainfall parameters are proposed. Besides, the model is scaled up to full-size, and real-scale tunnel fires under the influence of rainfall are evaluated. Findings draw attention to tunnel fire dynamics under extreme weather conditions for improved fire safety and evacuation strategies.

Since the large-scale oil exploration and development in the 1960 s, the Yellow River Delta (YRD) has undergone rapid industrialization and urbanization. Concurrently, the regional landscape ecological structure has experienced significant changes, and the degree of landscape fragmentation has increased. Therefore, a comprehensive assessment of the spatiotemporal dynamics and formation mechanisms of landscape fragmentation is crucial for the protection and restoration of natural ecosystem in the YRD. This study constructs an evaluation index system for landscape fragmentation in the YRD from three perspectives: quantitative characteristics, shape features, and spatial distribution. By combining inflection point analysis, landscape area loss index, and geostatistical models, the optimal spatial scale of landscape fragmentation from 2000 to 2020 is determined. Additionally, the study analyzes the spatiotemporal changes in landscape fragmentation and employs the optimal parameters-based geographical detector (OPGD) model to reveal the formation mechanisms of spatial heterogeneity in landscape fragmentation. The study findings are as follows: (1) The optimal spatial resolution for analyzing landscape fragmentation in the YRD was 80 m, and the extent was 880 m. (2) Between 2000 and 2020, landscape fragmentation in the YRD increased, with the highest level recorded in 2020. Highly fragmented areas, particularly inland regions, expanded remarkably, whereas coastal areas experienced lower fragmentation levels. (3) Distance to rivers and ditch density were the primary factors affecting landscape fragmentation, followed by land-use type and average land gross domestic product. The influence of natural factors was relatively minimal. The interaction between factors had a greater influence on landscape fragmentation compared to individual factors. The distance to rivers and land-use type exhibited the most substantial enhancement effects following interaction with other factors. This study provides valuable insights into the spatiotemporal dynamics and mechanisms of landscape fragmentation in the YRD, providing valuable guidance for the sustainable management and ecological restoration of the region and other similar ecologically sensitive areas.

With rapid urbanization, the conflicts between economic development and environmental protection have become increasingly complex and exhibit multiscale characteristics. Constructing a green space ecological network (EN) is an effective approach to alleviate urban ecological issues and maintain regional ecological security. However, traditional EN research often focuses on a single scale, neglecting multiscale nesting and collaborative optimization of landscape elements, particularly the importance of spatial granularity. To address this deficiency, this study proposed a multiobjective, multiscale nested green space EN framework for Chengdu, China. Using landscape pattern index fitting functions, morphological spatial pattern analysis, the connectivity index, circuit theory, hydrological analysis model, scale nesting, and hierarchical transmission theories, a multiscale coupled synergistic and hierarchical optimization regional green space ecological security pattern (ESP) was developed. Analysis of the derived results revealed the following. ① With increasing granularity, the landscape pattern indices showed overall increasing, overall decreasing, and overall fluctuating trends. The optimal granularity threshold for large, medium, and small scales was 9, 6, and 3 m, respectively. ② Overall, 92, 66, and 88 ecological sources; 403, 278, and 321 ecological corridors; 72, 77, and 47 pinch points; 96, 94, and 88 barriers; and 182, 120, and 87 ecological nodes were identified in the city, central city, and old city areas, respectively. ③ The ENs demonstrated reasonable hierarchical nesting characteristics, essential for interscale material and energy circulation. There were 9 overlapping ecological sources with total area of 18.34 km2 and 47 overlapping corridors with total length of 53.37 km. These overlapping areas were key regions for ensuring stability in the overall regional ESP and continuity in biological processes, and should be given priority protection. In addition, there were also 19 overlapping pinch points, 12 overlapping barriers, and 4 ecological nodes that accounted for 26.39 %, 24.68 %, and 40.43 % of the total pinch points; 12.50 %, 12.77 %, and 13.64 % of the total barriers; and 2.20 %, 3.33 %, and 4.60 % of the total ecological nodes in the city area, central city area, and old city area, respectively. The high overlap of ecological strategic points across scales indicated cross-scale continuity of biological processes. ④ Enhancing the habitat quality of land types such as forest land, green spaces, grassland, and water bodies is crucial for restoration of ecological corridors and strategic points. Constructing a multiscale hierarchical linkage framework and formulating cross-scale pattern optimization and coordination schemes can effectively address ecological issues. The multiscale nested and synergistic green space ESP, constructed from the “source–corridor–strategic-point–network” framework, enhances the connectivity of regional landscape elements, increases energy flow efficiency, and strengthens spatial stability. The results provide methodological support for strategic policymaking focused on ecological spatial governance of an urban ecological protection at multiple levels.

In karst regions, water scarcity often challenges vegetation’s carbon balance. While carbon and water use efficiencies (CUE and WUE) are crucial metrics, traditional assessments lack a comprehensive evaluation of their combined impact. This study bridged this gap by introducing carbon–water compound use efficiency (COM) and investigating its key drivers in the Yunnan-Guizhou Plateau using exploratory spatial analyses to identify the scale effect of spatial divergence of COM, and then explored the driving forces of COM from natural and human factors at optimal scale using the optimal parameter geo-detector (OPGD) and geographically weighted regression (GWR) model. The findings revealed that (1) Between 2000 and 2018, the mean CUE in the Yunnan-Guizhou Plateau karst regions exceeded that of non-karst areas, while the mean WUE and COM were lower in the karst areas compared to non-karst areas. (2) except for CUE, the WUE and COM tended to increase, and the change rates were greater in the karst areas; (3) NDVI dominated the spatial divergence of COM, showed a shift from a negative correlation in the eastern to a positive correlation in the western of the study area. These findings shed light on the unique dynamics of CUE and WUE in karst landscapes, providing valuable insights for targeted ecological restoration projects and promoting a sustainable balance between carbon and water resources.

The displacement efficiency and residual oil saturation are the most important characteristics determining the recoverable volumes of oil and the waterflooding efficiency. The main data about these parameters are provided by laboratory core studies. Specialized field tests make it possible to evaluate the same characteristics in-situ, directly on a well, thus excluding the influence of scale effect and impact of core sampling and preparation.This paper presents the results of a field study to evaluate the displacement efficiency and residual oil saturation on a well draining terrigenous Devonian formations on one of the areas of the Romashkinskoye field. The results are compared with generalized dependencies based on core data. Significant influence of the scale effect (the effect of sweep multiplicity) on the estimated parameter values was noted, which indicates the need to supplement laboratory experiments with specialized field studies.

Urban vitality is an essential reference for formulating urban planning and urban development policies, while the Modifiable Areal Unit Problem (MAUP) is a crucial issue that affects the accurate assessment of urban vitality and the understanding of its driving factors. Currently, MAUP in urban vitality studies has not received sufficient attention, and there are limited investigations on whether MAUP significantly affects the spatial autocorrelation of urban vitality. Moreover, existing studies have mainly focused on the impact of individual factors on urban vitality, with minor consideration of the interactions between factors and their effects on urban vitality at different spatial scales. This study takes the Pearl River Delta Core (PRDC) region as the research area. It used the Optimal Parameters-based Geographic Detector (OPGD) model and spatial autocorrelation to analyze the impact of the MAUP on urban vitality and its Built Environment (BE) factors. The results indicated that (1) the five types of BE driving factors, including work, living, rest, traffic, and Points of Interest (POI) diversity, were spatially sensitive and exhibited scale threshold effects. (2) The zoning schemes demonstrated the ability to alter the explanatory power (q-value) of driving factors and their trends. The spatial granularity and aggregation level of the grid-based zoning scheme, NPP-VIIRS nighttime light zoning scheme, and land surface temperature zoning scheme exhibited a logarithmic relationship, where spatial autocorrelation levels decreased with increasing aggregation level. (3) Compared to single-factor effects, the interactive effects of BE factors exhibited a higher q-value for urban vitality. Additionally, the q-values for factor interactions were more stable in multiple spatial scales than those q-values for individual factors. This study provides decision-making references for urban planners and policymakers to accurately assess urban vitality and find balanced, improved paths to enhance it.

This paper aims to show the scale effects of vertical maneuvering derivatives for an underwater vehicle using computational fluid dynamics (CFD). The model scale and full-scale benchmark DARPA suboff hull forms were used in numerical vertical planar motion mechanism simulations to achieve this aim. The heave forces, pitch moments, and Euler coefficients are calculated together with the linear vertical maneuvering derivatives by implementing the Fourier series expansion approach. The results show that the coupled added mass terms are significantly influenced by the scale effects, whereas the impact of scale effects on the decoupled added mass and coupled and decoupled damping terms is negligible. Considering that the effects of the coupled added mass on the vertical maneuvering characteristics are almost negligible, the vertical maneuvering of a submarine is slightly influenced by the scale effects.

ABSTRACTFine-scale population estimation (FPE) is crucial for urban management. After training, the bottom-up FPE models can be applied independently of census data. However, given the lack of real fine-scale population data, the existing bottom-up methods typically apply models trained on coarse-grained census data to FPE directly, causing estimation bias induced by scale effects. Traffic analysis zones (TAZs) balance geo-semantics and fine granularity, but their potential as population analysis units has not been fully exploited. Hence, we developed a weakly-supervised TAZ-scale bottom-up population estimation method (WSTP). Specifically, to mitigate scale effects, the weakly-supervised training procedure involves fine-scale feature input, model prediction, spatial aggregation, and coarse-scale supervision is designed to ensure that WSTP consistently focuses on FPE throughout the training and prediction phases. To enable weakly-supervised training using census data, we treated TAZs as graph nodes and designed a Spatial Aggregation Layer to aggregate TAZ-scale population predictions into communities. Given the diverse distribution patterns across age groups, we decomposed the FPE task by age groups. The experiments showed that WSTP significantly outperformed the baselines with R2 values of 0.821 and 0.785 at the community and TAZ scales, respectively, indicating that WSTP can mitigate scale effects and produce high-resolution, accurate population data.

ABSTRACTLaser powder bed fusion (LPBF) of multi-scaled structures is a prominent direction pursued by innovative designs and engineering applications. However, understanding the impact of scale effect on the effectiveness of actual structures is a pressing challenge. This work investigates the influence of structure scale on surface morphology and mechanical property by fabricating tensile samples with gauge diameters ranging from 0.2 mm to 5.0 mm. For the hatching scanning strategy, the surface roughness drastically reduces by ∼51% as the diameter increases. This appears to be the coupling results of heat accumulation, molten pool morphology at the end of single-track, overlap between multi-tracks within a layer, and successive rotational buildup between layers. Moreover, decreasing the diameter substantially reduces the tensile strength. Fortunately, a hatching-contour scanning strategy is proposed to eliminate the scale effect of surface morphology and strength. These efforts provide essential guidance for the broader application of multi-scaled structures.

The crack resistance of concrete structures with low reinforcement ratios requires a broader examination. It is particularly important in the case of foundations working in changing subsoil conditions. Unfavorable phenomena occurring in the subsoil (e.g., ground subsidence, landslips, non-uniform settlement) can lead to unexpected cracking. Therefore, it is necessary to check the effectiveness of the low reinforcement provided. As there are limited studies on lightly reinforced concrete structures, we performed our own experimental investigation and numerical calculations. In the beams analyzed, the reinforcement ratio varied from 0.05% to 0.20%. It was found that crack resistance in concrete members depends on the reinforcement ratio and steel bar distribution. A comprehensive method was proposed for estimating the crack resistance of lightly reinforced concrete members in which both the reinforcement ratio and the reinforcement dispersion ratio were taken into account. Furthermore, the method considered the size effect and the fracture properties of concrete. The proposed method provides the basis for extrapolation of the test results obtained for small elements and conclusions for members with large cross-sections, such as foundations, which frequently use lightly reinforced concrete. [ABSTRACT FROM AUTHOR]

The Yangtze River Basin serves as an essential ecological shelter in China, yet it has encountered escalating aquatic ecological challenges. Exploring the spatial–temporal changes and the trade-off–synergy relationships of water-related ecosystem services (WESs) is necessary for formulating management and planning policies targeting the sustainable development of watersheds. In this study, the InVEST model is utilized to evaluate the spatial–temporal variations in water yield (WY), water purification (WP), and soil conservation (SC) in the Yangtze River Basin using remote-sensed data from 2001 to 2021. The spatial overlay method and a correlation analysis were adopted to reveal the trade-off–synergy relationship among the three WESs. Additionally, we performed a comparative analysis across the grid and sub-basin scales. The results showed that the multi-year average WY, WP, and SC were 536.10 mm, 1.32 kg/ha, and 250.08 t/ha, representing increasing rates of 4.74 mm/a, −0.001 kg/ha/a, and 1.88 t/ha/a, respectively. Moreover, the trade-off–synergy relationships of WESs exhibited spatial variability; specifically, the WY-WP, WP-SC, and WY-SC pairs demonstrated reduced synergy magnitude over time. The WES interactions were stable across the scales of interest, while synergy strength showed noticeable variability. The findings may contribute to the sustainable development of the Yangtze River Basin and enhance the comprehensive management of WESs. [ABSTRACT FROM AUTHOR]

In order to study the scale effect in wave-structure interactions and the role that structure-related parameters (tension T or bending stiffness EI) plays, riser model tests under regular waves were conducted using the model with multiple geometric scales (1:15, 1:12 and 1:9) in a wave basin. The riser model used is a novel structural design combing the outer polyvinyl chloride pipe with the core steel rod which could be simplified as a cantilever beam. Different initial tension T acting on the riser are tested by adjusting the slotted weight. The results show that the amplitude varies in a cubic fashion with the distance from the fixed end. In addition, the influence of the wave period and top tension T on the amplitude are investigated, which ultimately leads to a dimensionless number π1 = KCd·TL²/EI where KC is the classical Keulegan-Carpenter number (KC), EI shows the bending stiffness of the riser model and L gives the pipe length. With the KC number revised to take the distance from the fixed end into the calculation, this parameter provides a good measure in estimating the amplitudes of the riser vibrations induced by the waves. [ABSTRACT FROM AUTHOR]

Grasping the interrelationship between the supply and demand of ecosystem services (ESs) and spatial scale characteristics is the foundation for effective ecological zoning management, which helps to realize a win–win situation for both ecological protection and economic development. This paper focuses on the following three real problems: mismatch in ES supply and demand evaluation, mechanical and subjective delineation of ecological zoning, and rough management strategies, and constructs a multi-scale ecological zoning management framework for the "comprehensive evaluation of supply and demand, ecological zoning, and enhancement of human well-being". This study integrates the InVEST model, SOM, Z-score quadrant matching, and coordination degree method, and applies them to the ecological management zoning of Hangzhou. The results show that (1) the spatial differentiation of ESs in Hangzhou is significant. The spatial pattern of the five types of ES supply varies at the county scale and the grid scale on which ES demand is concentrated and is consistent at different scales. (2) ES supply–demand matching in Hangzhou is at the basic coordination and can be divided into four modes including HH, LH, LL, and HL at both the county and grid scales. On the small scale, the proportion of mismatches declines slightly, but the severity rises. (3) ES supply is divided into four categories as follows: the food production bundle, the carbon storage bundle, the ESs balancing bundle, and the ESs depleting bundle, and clarifies the priority of ES management. (4) Construct an ecological management practice path, delineates 6 ecological management zones at the county scale and 19 secondary management zones at the grid scale. Targeted measures are proposed in terms of supply–demand adjustment strategies, ecological management strategies, and key implementation areas. This study helps to incorporate the interaction between the supply and demand of ESs into the planning framework and provides decision-making support for refined ecological management. [ABSTRACT FROM AUTHOR]

Economic agglomeration has played a key function in China's economic transformation. Meanwhile, structural adjustment and external pressure to reduce carbon emission necessitate a deeper investigation into its relationship with carbon productivity. This paper measures economic agglomeration and carbon productivity of 281 cities in China in 2003–2017. With the purpose of exploring the spatial effect of economic agglomeration on carbon productivity, a spatial Durbin model is constructed. In addition, the mediation effect model is also adopted for examining the transmission mechanism of economic scale and technological progress on economic agglomeration as well as carbon productivity. A heterogeneity test is also carried out to uncover the varying effects of economic agglomeration on carbon productivity. The empirical results suggest that economic agglomeration raises carbon productivity not only in the local cities but also in the neighbouring ones. The impact of economic agglomeration on carbon productivity becomes more potent as the level of economic agglomeration increases. For cities with low level of economic agglomeration, the effect is mainly achieved through the expansion of economic scale, but for cities with high level of economic agglomeration, the effect is mainly achieved through technological progress. Therefore, we suggest encouraging carbon productivity improvement through technology effect in cities with high economic agglomeration level, while enhancing carbon productivity through scale effect in cities with low economic agglomeration level. [ABSTRACT FROM AUTHOR]

At present, titanium alloy/carbon fiber reinforced polymer (TA1/CFRP) laminates, representing the latest fourth generation of fiber metal laminates (FMLs), are predominantly applied in the field of aerospace. The miniaturization of traditional FMLs in thickness or plane size to the micron level for the study of structural properties of ultra-thin laminates will further expand the application of FMLs in the field of micro-devices. Given that carbon nanotubes have a strengthening mechanism in polymers. However, most existing studies have focused on the effect of carbon nanotubes on the properties of macro-scale FMLs, while the enhancement mechanism of the interfacial and mechanical properties of ultra-thin micro-scale FMLs has not been studied, leaving the mechanism still unclear. Based on this, this paper explores the interfacial deformation mode, damage fracture and performance enhancement mechanism of the ultra-thin TA1/CFRP laminates by comparing the parameters of tensile strength and elongation under quasi-static conditions and different process parameters of multi-walled carbon nanotubes content, test temperature, geometry size and grain size. Meanwhile, the correlation law between high-speed tension and quasi-static tension is determined, a 29.3 % increase in tensile strength as the strain rate rises from 0.001 s−1 to 100 s−1, yielding the basic deformation law of ultra-thin FMLs.

Accurately identifying the optimal spatial scales of effect analysis of influencing factors on water quality is crucial for effective water environment management. To address this, we propose a framework that consists of mix scale division (watersheds, riparian buffers, and circular buffers), and conduct a case study in the Yuanjiang River Basin (YJRB). Scale effects and non-linear impacts of various influencing factors on water quality were identified. The case study results revealed the variations of these water quality indicators were predominated by different influencing factors at various sales, such as by slope (SL) at the scale of riparian buffer (w) = 500 m and circular buffer (r) = 15 km (with a contribution percentage of 16.6 %), mean annual temperature (TE) at the watershed scale (23.4 %), annual precipitation (PR) at the scale of w = watershed and r = 15 km etc. The percentage of cultivated land (CL) > 28 % at the scale (w = 500 m, r = 50 km) will lead to increase in total phosphorus (TP) and SL > 26° at the scale (w = 500 m, r = 15 km) will lead to increase in pondus hydrogenii (pH). While, POP > 30 person per unit area at the scale (w = 100 m, r = 1 km), SL > 24° at the scale (w = 500 m, r = 15 km), NDVI > 0.48 at the scale (w = 500 m, r = 5 km) and PR > 1300 mm at the scale (w = watershed, r = 15 km) will lead to decrease in ammonia nitrogen (NH3-N), total nitrogen (TN), electrical conductivity (EC) and turbidity (NTU) respectively. Results indicated that the precision can be improved by regulating influencing factors within scale effects and considering the non-linear effects of factors on water quality.

Amidst swift socioeconomic progress, urbanization is intensifying, necessitating robust methodologies for environmental quality monitoring. Landscape Ecological Risk (LER) has emerged as a pivotal tool in this context. Extensive research has focused on the land utilization rates within watersheds, scrutinizing them through the lens of land use/land cover (LULC) dynamics. This study delves into the LULC attributes of the Bosten Lake Basin (BLB) across three temporal snapshots: 2000, 2010, and 2020. Grasslands and bare ground made up the vast majority area of the BLB. Selected twelve landscape pattern indices, analyzed their response curves with respect to grain size, determined the optimal grain size to be 150 m, and analysed its optimum amplitude of 10 km × 10 km on the basis of the semi-variance function, thus determined the optimal scale for analyzing the landscape pattern. Exploring scale effect facilitates a nuanced examination of the landscape patterns and land use efficacy within BLB. From 2000 to 2020, the landscape pattern showed less fragmented, less aggregated, and more spatially heterogeneous. The landscape ecological risk index model has been constructed for the investigation of the LER change characteristics of the BLB. Lowest-risk zones and lower-risk zones of LER predominate in BLB. In 2000, 2010 and 2020 the combined lower and lowest risk zones represent 62.02 %, 59.37 % and 58.44 % of the catchment area respectively. Finally, analyzed the spatial autocorrelation variation characteristics of LER. The global Moran' I index of BLB for the three periods from 2000 to 2020 exceeded 0.7. This study establishes theoretical and practical foundation for future multi-scale landscape ecological risk studies in eco-fragile regions.

This paper investigates possibilities of reducing production inefficiency using same input vector. Firms mostly suffer technical inefficiency in their production. Producers are found to operate below the frontier. Hence, empirical measures of production efficiencies are necessary to determine the inefficiency level, magnitude of inefficiency reduction, and gains that could be obtained by improving performance in the sector. The study used secondary data collected from Food and Agriculture Organization (FAO) and the National Bureau of Statistics (NBS) database. The dataset covers the period 1960-2021. Variables extracted included agricultural GDP (kg), fertiliser usage (kg), agricultural labour(man-days), and number of tractors (No). The data were subjected to a unit root test for stationarity, and a stochastic frontier production/ Cost function model were applied to determine technical inefficiency of variables in the model. The result of unit root shows that series are integrated of the first order I (1). AIC criteria indicate an optimal lag length of two years, while the Unrestricted Co-integration Trace and Maximum Eigenvalue test show strong evidence of long-run relationship amongst variables. The parameters of Stochastic Frontier Production Function estimated were positively consistent with the study’s a priori expectation for such variables as fertiliser (0.2634), labour (0.3159), land (0.1846), and tractor (0. 1587). Output-oriented technical efficiency is 0.7802 (78%) and 22% is technically inefficient. A decreasing returns to scale value of (0.9226) with a scale effect of 0.9226. The sector is 58% economically efficient with cost savings of 42% and 75% allocative efficiency. This study concludes that Nigeria’s agriculture suffers from production inefficiencies and this inefficiency can be reduced by using the same input levels.

The joint roughness coefficient (JRC), introduced in Barton (1973) represented a new method in rock mechanics and rock engineering to deal with problems related to joint roughness and shear strength estimation. It has the advantages of its simple form, easy estimation, and explicit consideration of scale effects, which make it the most widely accepted parameter for roughness quantification since it was proposed. As a result, JRC has attracted the attention of many scholars who have developed JRC-related methods in many areas, such as geological engineering, multidisciplinary geosciences, mining mineral processing, civil engineering, environmental engineering, and water resources. Because of such a developing trend, an overview of JRC is presented here to provide a clear perspective on the concepts, methods, applications, and trends related to its extensions. This review mainly introduces the origin and connotation of JRC, JRC-related roughness measurement, JRC estimation methods, JRC-based roughness characteristics investigation, JRC-based rock joint property description, JRC's influence on rock mass properties, and JRC-based rock engineering applications. Moreover, the representativeness of the joint samples and the determination of the sampling interval for rock joint roughness measurements are discussed. In the future, the existing JRC-related methods will likely be further improved and extended in rock engineering.

Satellite-derived Land Surface Temperature (LST) plays an important role in research on natural energy balance and water cycle. Considering the tradeoff between spatial and temporal resolutions, accurate fine-resolution LST must be obtained through the use of LST downscaling (DLST) technology. Various methods have been proposed for DLST at fine resolutions (e.g., 10 m) and small scales. However, the scale effect of these methods, which is inherent to DLST processes at different extents, has rarely been addressed, thus limiting their application. In this study, a modified daily 10 m resolution DLST method based on Google Earth Engine, called mDTSG, is proposed in order to reduce the scale effect at fine spatial resolutions. The proposed method introduces a convolution-based moving window into the DLST process for the fusion of different remote sensing data. The performance of the modified method is compared with the original method in six regions characterized by various extents and landscape heterogeneity. The results show that the scale effect is significant in the DLST process at fine resolutions across extents ranging from 100 km2 to 22,500 km2. Compared with the original method, mDTSG can effectively reduce the LST value differences between tile edges, especially when considering large extents (>22,500 km2) with an average R2 improvement of 33.75%. The average MAE is 1.63 °C, and the average RMSE is 2.3 °C in the mDTSG results, when compared with independent remote sensing products across the six regions. A comparison with in situ observations also shows promising results, with an MAE of 2.03 °C and an RMSE of 2.63 °C. These findings highlight the robustness and scalability of the mDTSG method, making it a valuable tool for fine-resolution LST applications in diverse and extensive landscapes.

In the modified formula for the cubic law, the roughness correction coefficient C serves as a parameter that indicates the characteristics of the roughness of a rock’s surface. In this study, surface data for natural rock samples were acquired through high-precision 3D scanning and combined with publicly accessible CT scan data on rough rock fractures to generate spatial coordinates. The roughness correction coefficient C was calculated and analyzed using both formulaic and numerical methods. The analysis revealed significant effects of scale on the roughness correction coefficient for rock fractures within a size range of 5 to 10 cm (determined based on the actual sample size), with tensile fractures demonstrating greater variations compared to shear fractures. When calculating the roughness correction coefficient on the same fracture surface in different directions, significant directional effects were observed. Furthermore, elliptical fitting demonstrated favorable results. The conclusion drawn was that the roughness correction coefficient for fracture surfaces can be represented effectively using a tensor form, thereby simplifying the expression of directionality. Calculating and analyzing the fractal dimension of a rough surface further confirmed the existence of effects of size on roughness.

Slant range geometry plays a crucial role in interpreting synthetic aperture radar (SAR) observations, especially in converting line-of-sight (LOS) surface deformations to actual vertical subsidence. This paper proposes a new conversion model to retrieve vertical settlements of the embankment slopes using the geometrical parameters of the dam and the SAR sensor. The simulation results highlight the impact of slope foreshortening and heading direction of the satellite on deformation retrieval. Various SAR data with different resolutions and bands are used to analyze the model's performance, revealing a high conformity of the model with practical conversion parameters exceeding 80% for TerraSAR-X and Cosmo-SkyMed data. [ABSTRACT FROM AUTHOR]

In the present study, the added resistance, heave, and pitch of the KRISO Container Ship (KCS) in waves, at both model scale and full scale, are predicted numerically in regular head waves, for four wavelengths and three wave heights. The ISIS-CFD viscous flow solver, implemented in the Fidelity Fine Marine software provided by CADENCE, was employed for the numerical simulations. The spatial discretization was based on the finite volume method using an unstructured grid. The unsteady Reynolds-averaged Navier–Stokes (RANS) equations were solved numerically, with the turbulence modeled by shear stress transport (k-ω) (SST). The free-surface capturing was based on the volume-of-fluid method. The computed solutions were validated through comparisons with towing test data available in the public domain. To predict the uncertainties in the numerical solution, a systematic grid convergence study based on the Richardson extrapolation method was performed for a single wave case on three different grid resolutions. Specific attention was given to the free-surface and wake flow in the propeller plane. The purpose was to compare the numerical results from the model- and full-scale tests to examine the scale's effect on the ship's performance in regular head waves. The comparison between the model scale and full scale showed obvious differences, less accentuated for the free-surface topology and clearly observed in terms of boundary layer formation in the propeller's vicinity. [ABSTRACT FROM AUTHOR]

Rural tourism serves as a crucial means for fostering rural economic prosperity and inheriting rural culture. The assessment of the quality of rural tourism development and the identification of disparities in rural tourism development among regions have become focal points in current research. This paper utilizes tourism big data to establish a system for evaluating rural tourism popularity and proposes a method for identifying rural tourism hotspots. The study explores the spatiotemporal evolution characteristics and formation mechanisms of the cold and hot patterns of rural tourism in China during two periods (pre-pandemic and post-pandemic) and on two spatial scales (provincial and municipal levels). The research findings indicate that (1) the annual variation in rural tourism popularity exhibits a fluctuating upward trend, with significant seasonal variations on a monthly basis. (2) The spatial pattern of rural tourism popularity changes with the scale effect. At the provincial level, hotspot areas form an east–west dual-core pattern, while at the municipal level, hotspot areas demonstrate an evolution from a three-core to a four-core pattern. In the post-pandemic era, rural tourism popularity in the northwest and southwest regions is experiencing a counter-trend growth. (3) At different spatiotemporal scales, influencing factors and their impact intensities vary. At the provincial level, road density and reception capacity consistently play dominant roles, and per capita disposable income significantly influences early-stage popularity enhancement. At the municipal level, resident population and tourism resources influence are the dominant factors, and the influence of air quality and regional media attention gradually strengthens. This article provides a new perspective on quantitative research in rural tourism, offering significant guidance for the rational allocation of resources in rural tourism, regional tourism collaboration, and the sustainable development of rural tourism in the post-pandemic era. [ABSTRACT FROM AUTHOR]