Patch Shape Research Articles

An artificial neural network model for multi-flexoelectric actuation of Plates

ABSTRACT Flexoelectric effect can be used to design actuators to control engineering structures including beams, plates, and shells. Multiple flexoelectric actuators method has the advantage of less stress concentration and better control effect, but the mode-dependent optimal actuator locations could influence the flexoelectric actuation effect significantly. In this work, a neural network model is established to study the optimal combinations of multiple flexoelectric actuators on a rectangular plate. In the physical model, an atomic force microscope (AFM) probe was employed to generate an electric field gradient in the flexoelectric patch, so that flexoelectric control force and moment can be obtained. Multiple flexoelectric actuators on the plate was considered. Case studies showed that the flexoelectricity induced stress mainly concentrate near the probe, the size and shape of the flexoelectric patch have limited effect on the actuation, hence, only the actuator positions were choosing as the input of the ANN model. Using the prediction of the neural network model, the driving effect of a large number of actuators at different positions can be quickly obtained, and the optimal position of the actuator can be analyzed more accurately.

Temporal dynamics of satellite-derived vegetation pattern and growth in an arid inland river basin, Tibetan Plateau

Exploring alpine vegetation dynamics and its driving factors help to predict changes in hydrothermal circulations at high elevations in the future. Currently, there is a lack of systematic research on this topic in the permafrost regions at a basin scale. Spatiotemporal variations of vegetation pattern and growth estimated from satellite remote sensing images at a 30 m spatial resolution on the Google Earth Engine cloud platform were investigated in the Shule River headwater region from 2000 to 2021. The results showed shrinking trends in alpine grassland (AG) and wetland (AW) area, while an expanding trend in alpine desert (AD) area. AD moved to lower altitudes and occupied AG and AW area, possibly owing to mountain permafrost degradation and extreme precipitation. Vegetation patches became fragmented and complex, reflected by increases in patch number and shape index. Vegetation growth, as approximated by the normalized difference vegetation index (NDVI), increased significantly in 42 % of the vegetated area ( p < 0.05), particularly in river valleys. In addition, NDVI was negatively correlated with solar radiation over 30 % of the vegetated area ( p < 0.05). At the regional scale, vegetation NDVI was positively correlated with root-zone soil moisture and grazing intensity ( p < 0.05). The findings suggested that AG and AW at their upper limit of distribution were vulnerable to soil erosion, and the inter-annual variation of vegetation growth was affected by soil moisture and grazing. Moreover, future climate warming may cause alpine vegetation decline by increasing active layer thickness in the absence of adequate precipitation supply. • Alpine desert mainly invades downward into alpine wetland. • Vegetation patches tend to be fragmented. • NDVI increases significantly in alpine desert. • A negative correlation between NDVI and solar radiation is observed. • Regional vegetation NDVI positively correlates with grazing intensity.

3D mesh transformer: A hierarchical neural network with local shape tokens

Self-attention networks have revolutionized Natural Language Processing (NLP) and are making impressive strides in image analysis tasks such as image classification and object detection. Inspired by this success, we specifically design a novel self-attention mechanism between local shapes and build a shape Transformer. We split the 3D mesh model into shape patches, which we call shape tokens, and provide polynomial fitting representations of these patches as input to the shape Transformer. The shape token encodes local geometric information and resembles the token (word) status in NLP. The simplification of the mesh model provides a hierarchical multiresolution structure, which allows us to realize the feature learning of a multilayer Transformer. We set high-level features formed by the shape Transformer as visual tokens and propose a vector-type self-attention mechanism to construct a 3D visual Transformer. Finally, we realized a hierarchical network structure based on local shape tokens and high-level visual tokens. Experiments show that our fusion network of 3D shape Transformer with explicit local shape context augmentation and 3D visual Transformer with multi-level structural feature learning achieves excellent performance on shape classification and part segmentation tasks.

Use of combined CZM and XFEM techniques for the patch shape performance analysis on the behavior of a 2024-T3 aluminum structure reinforced with a composite patch

The presence of a geometric discontinuity such as a crack or a notch can cause the failure of a structure during its use. Under various mechanical or thermal stresses, a high concentration of stresses can take place at the level of these discontinuities, which in most cases will lead to the total failure of the structure. The service life of these structures can be improved with the use of the repair technique by bonding a composite patch. This technique is of significant interest in several fields, especially with the use of composite materials. This technique is widely used in aeronautics and ensures a long life of damaged structures. Current research aims to optimize the shape size and fiber's nature of this composite patch in order to ensure good load transfer by reducing the stresses in the damaged area. In this work, a finite element method is used to analysis the effect of the shape of the patch on the global response of a 2024-T3 aluminum structure in the presence of a central circular notch. The composite patch is of the carbon/epoxy type bonded through an A-140 Adekit type adhesive on the damaged part of the plate. The analysis consists in determining the force-displacement curves of the repaired structure by using the combination of the two techniques, XFEM for the damage of the aluminum plate 2024-T3 by the automatic creation of the crack and CZM for the analysis of the adhesive debonding. The analysis takes into account the damage in the plate and in the adhesive. However, for the composite patch, and since there will be no damage, we have just analyzed the effect of its shape and essentially the shape of its edges on the load transfer and consequently on the resistance of the structure under loading in tension. Two main patch shapes have been highlighted, namely the square and circular shape. The results show clearly that the shape of the patch’s edges has an impact on the stresses reduction in the plate and subsequently ensures good resistance in terms of force-displacement curve and consequently delays the peeling of the adhesive.

Benchmarking the Planar Honeycomb Code

We improve the planar honeycomb code by describing boundaries that need no additional physical connectivity, and by optimizing the shape of the qubit patch. We then benchmark the code using Monte Carlo sampling to estimate logical error rates and derive metrics including thresholds, lambdas, and teraquop qubit counts. We determine that the planar honeycomb code can create a logical qubit with one-in-a-trillion logical error rates using 7000 physical qubits at a 0.1% gate-level error rate (or 900 physical qubits given native two-qubit parity measurements). Our results cement the honeycomb code as a promising candidate for two-dimensional qubit architectures with sparse connectivity.

Urban Forest Locations and Patch Characteristics Regulate PM2.5 Mitigation Capacity

Atmospheric pollution caused by fine particulate matter (PM2.5) seriously damages human health. Urban forests have the ecological function of purifying the atmosphere, which can effectively reduce the ambient PM2.5 concentration. This paper analyzed the ability of different forest types to mitigate PM2.5 pollution and explored the effects of forest quality and morphological parameters on PM2.5 concentration on the forest patch level. The results concluded that the PM2.5 concentration of the Landscape and Relaxation Forest (LF) was significantly lower than that of the Roadside Forest (RF) and Affiliated Forest (AF) due to the environmental quality of their location. The effective distance of LF on PM2.5 reduction was 80 m, which was significantly higher than RF and AF. The Normalized Difference Vegetation Index (NDVI), which indicated forest growth status, was the most effective parameter for improving the urban forest PM2.5 mitigation ability. The concentration of PM2.5 decreased linearly with the increase in NDVI. The area and perimeter of the forest patches had a significant nonlinear negative correlation with PM2.5 concentration. In addition, the more irregular the shape of the forest patch, the lower the PM2.5 concentration of the forest. Moreover, the simpler shape of RF and AF helped to alleviate PM2.5 pollution. The round shape of AF more efficiently reduced PM2.5 concentration. Our study demonstrated that the surrounding environment, forest growth status, and patch forms determined the PM2.5 reduction capacity of an urban forest. The corresponding management and adjustment methods should be implemented in future urban forest management.

Substrate geometry effect on the strength of repaired plates: Combined XFEM and CZM approach

Aluminum alloys are commonly used in aeronautical applications because of their specific strength and improved corrosion resistance. These structures, during their service, are exposed to various loading cycles, eventually leading to failure at the loci of geometric discontinuities. Repairing by metal or composite patch bonding is widespread to extend the structures’ life by limiting stress concentrations and delaying crack initiation. This work consists of a numerical study, validated by experimental test data, to assess the effect of a central circular notch in an aluminum plate, either reinforced or not by an adhesively bonded composite patch, on the global tensile response of the structure. The constitutive law of the aluminum and adhesive is assumed nonlinear and follows Von Mises equivalent stress flow theory with a hardening variable in incremental form. Damage initiation in the aluminum alloy is modeled by the XFEM (eXtended Finite Element Method), using the maximum principal stress criterion (MAXPS) for damage initiation prediction. Damage evolution is based on the energy approach. The adhesive layer was modeled by CZM (Cohesive Zone Model). A good agreement was found between the experimental results of the tensile curves of the repaired and unrepaired plates with those resulting from numerical modeling. Once the numerical model was validated, several parameters werenumerically studied, namely the shape of the composite patch, the size of the notch, the nature of the adhesive and repair mode by single and double patch, to reduce maximum stress of the damaged area and provide maximum repair efficiency.

Generalisation of the linear theory of rolling contact to a single double-elliptic contact region and its application to solve non-Hertzian contact problems using extended FASTSIM

Most contact models addressing the solution of the tangential problem assume an elliptical shape of the contact patch which is derived from the Hertz theory. In particular, the linear theory of rolling contact developed by Kalker is based on this assumption. However, it is well known that in many practical cases the shape of the contact region formed between the rail and a railway wheel can be far from elliptic. Recently, the Simple Double-Elliptic Contact (SDEC) shape has been proposed as an approximation of a wide variety of non-elliptic patches. In this paper, a formulation of the linear theory of rolling contact for a SDEC shape is proposed. The coefficients of the original linear theory for elliptic patches are maintained and four new coefficients are introduced to consider the effect of non-ellipticity. The coefficients of the theory are derived numerically using software CONTACT. Then, an extension of FASTSIM for a SDEC region is introduced and the obtained creep force curves under various conditions are compared to existing formulations of FASTSIM, using results from software CONTACT as a reference. The comparisons show that the proposed model is as fast as FASTSIM and provides more accurate solutions than existing versions of FASTSIM.

Landscape and Stand Characteristics Influence on the Bird Assemblage in Nothofagus antarctica Forests of Tierra del Fuego

Different variables operate simultaneously at different spatial scales, influencing community composition and species distribution. This knowledge could improve management and conservation practices in managed menaced forests. The objective of this work was to determine the influence of landscape and stand variables on the bird assemblage of the managed Nothofagus antarctica forest of Tierra del Fuego (Argentina). We used data from bird point counts (three or four censuses during middle summer of two consecutive years) located at 48 sites distributed at four ranches. At each site, we extracted landscape variables with Fragstat software from the forest patches, the cover classes, and the whole landscape. We also evaluated local stand characteristics, such as forest structure, ground cover, and food availability, including understory plant cover usually consumed by birds and available arthropods. Data were evaluated by detrended and canonical correspondence analyses. We found that landscape configuration (e.g., forest patch shape) and local stand variables (e.g., canopy cover) influenced bird assemblage more than landscape composition. Moreover, bird functional groups responded differently to different spatial scale variables (e.g., forest specialist species were associated with forest structure, but species that use low strata to nest and feed were associated with landscape configuration variables), demonstrating the importance of using multiple spatial scales to better understand bird species requirements. The combination of practices that promote some local characteristics (e.g., high canopy cover) and more complex landscape configurations could simultaneously favor different bird species groups and improve the effectiveness of management and conservation strategies.

Landscape Metrics Explain the Ecological Susceptibility of Terrestrial Ecosystems

This study examines the effects of the change in the shape of landscape patches, known as landscape structure, on ecological susceptibility, which is defined using the object-oriented method. The aim is to determine whether ecological susceptibility is influenced by the shape of the landscape patches in the southern basin of the Caspian Sea. The multivariate linear regression approach is applied to discover the extent to which the mean, median, and weighted average of the landscape structure metrics can explain the total variations of the ecological susceptibility. To determine the optimal models, an intermodel comparison is conducted using the Akaike information criterion. Sensitivity and uncertainty analyses were performed to determine how sensitive ecological susceptibility is to changes in the variables of the models and how they behave under varying conditions. The models (0.64≥r2≥0.27, p ≤ 0.05) indicate that the landscape structure metrics can be applied to predict ecological susceptibility. Examining the mean, median, and weighted average of the landscape metrics in estimating ecological susceptibility also reveals that the models made by the mean and median values have less uncertainty than those developed by the weighted average. The results show that the regularity or irregularity in the shape of the landscape patches and the degree of contiguity of the land use/land cover patches can significantly affect ecological susceptibility. Closed deciduous broad-leaf forest patches, closed mixed forest patches, and open mixed forest patches can be considered crucial land use/land covers to estimate ecological susceptibility.

Health Risk Assessment and Influencing Factors Analysis of High Temperatures on Negative Emotions

The emotional health of urban residents has been seriously threatened by frequent and normalized heat waves. This study constructed the VI-level assessment standard for emotional health risk using data from satellite images, meteorological sites, questionnaire surveys, and statistical yearbooks to assess the effect of high temperatures on negative emotions in Hangzhou. The results showed that the morphological changes of urban high-temperature areas were aggregated from a cross-shape to a large patch shape, then dispersed into cracked patch shapes. Additionally, the health risk of daytime negative emotions peaked at the VI-level from 1984 to 2020, and the influence level of the typical period risk increased by 1–2 levels compared with the daytime. Additionally, driven by urban spatial structure policies, the risk pattern of emotional health expanded outward from a single center into multiple centers. The emotional health risk level rose and then descended in urban centers, and the innovation industries drove the variation tendency of hot spots. Furthermore, high educational background, employment, and couples living together were critical variables that could alleviate the emotional health risk to the middle-aged and elderly population. This study aimed to optimize the urban spatial structure and alleviate residents’ emotional health hazards for healthy urban planning.

Structure‐from‐motion photogrammetry demonstrates that fine‐scale seascape heterogeneity is essential in shaping mesophotic fish assemblages

AbstractBenthic components of tropical mesophotic coral ecosystems (MCEs) are home to diverse fish assemblages, but the effect of multiscale spatial benthic characteristics on MCE fish is not well understood. To investigate the influence of fine‐scale benthic seascape structure and broad‐scale environmental characteristics on MCE fish, we surveyed fish assemblages in Seychelles at 30, 60 and 120 m depth using submersible video transects. Spatial pattern metrics from seascape ecology were applied to quantify fine‐scale benthic seascape composition, configuration and terrain morphology from structure‐from‐motion photogrammetry and multibeam echosounder bathymetry and to explore seascape–fish associations. Hierarchical clustering using fish abundance and biomass data identified four distinct assemblages separated by the depth and geographic location, but also significantly influenced by variations in fine‐scale seascape structure. Results further revealed variable responses of assemblage characteristics (fish biomass, abundance, trophic group richness, Shannon diversity) to seascape heterogeneity at different depths. Sites with steep slopes and high terrain complexity hosted higher fish abundance and biomass, with shallower fish assemblages (30–60 m) positively associated with aggregated patch mixtures of coral, rubble, sediment and macroalgae with variable patch shapes. Deeper fish assemblages (120 m) were positively associated with relief and structural complexity and local variability in the substratum and benthic cover. Our study demonstrates the potential of spatial pattern metrics quantifying benthic composition, configuration and terrain structure to delineate mesophotic fish–habitat associations. Furthermore, incorporating a finer‐scale perspective proved valuable to explain the compositional patterns of MCE fish assemblages. As developments in marine surveying and monitoring of MCEs continue, we suggest that future studies incorporating spatial pattern metrics with multiscale remotely sensed data can provide insights will that are both ecologically meaningful to fish and operationally relevant to conservation strategies.

Assessing the fast non-Hertzian methods for wheel-rail rolling contact integrated in the vehicle dynamics simulation

An accurate and high-efficiency contact model is essential for vehicle-track dynamic simulation and wear prediction. The paper attempts to assess the influence of different contact models on the offline and online simulation, as well as wear depth distribution. Taking CONTACT as the reference model, the computational accuracies of contact model combinations (i.e. Hertz + FASTSIM, Kik–Piotrowski (KP) + FASTSIM, modified Kik–Piotrowski (MKP) + FASTSIM and MKP + FaStrip) are evaluated. Typical wheel-rail contact cases and two dynamic simulation cases (track irregularity and curve track) have been studied. Results show that MKP + FaStrip achieves the best computational accuracy in calculating the typical wheel-rail contact situation, besides, the yaw angle has a significant influence on the contact patch shape and pressure distribution, especially when the wheel flange contacts with a rail corner. With regard to the vehicle passing the track with the lateral irregularity, both KP + FASTSIM and MKP + FaStrip models can achieve relatively good agreement on dynamic results and wear prediction with CONTACT. In terms of the curve track, MKP + FaStrip has better accuracy on dynamic results and wear due to a larger yaw angle.

Spatial-temporal characteristics of cultivated land use eco-efficiency under carbon constraints and its relationship with landscape pattern dynamics

With China’s rapid urbanization and socioeconomic development, cultivated land has been experiencing continuous reduction, spatial shift, and ecological degradation in the past few decades, coupled with the decreasing and aging agricultural labor force, thus improving cultivated land utilization efficiency while minimizing associated environmental impacts is one of the major challenges facing China. This study first establishes an index system to access the eco-efficiency of cultivated land use (EECLU) considering both carbon sequestration and carbon emissions, next, employs the Super-SBM model to evaluate the spatial–temporal characteristics of EECLU, then, uses landscape metrics to describe landscape pattern dynamics of cultivated land, and finally conducts panel data analysis to investigate the relationship between landscape pattern changes and the EECLU variations. This framework was applied to Jiangsu Province, a major grain-producing area with a developed economy. The results showed that the average EECLU of the counties in rural Jiangsu from 2000 to 2020 slightly decreased, most counties were in the medium–low efficiency range (0.6–0.8), and Southern Jiangsu generally has the lowest EECLU values while Central Jiangsu has the highest. The total area and the average patch sizes of cultivated land have significantly positive impacts on EECLU, while the shape complexity and patch fragmentation have significantly negative impacts on EECLU. Therefore, comprehensive low-carbon strategies and better management and technology in the agricultural sector are needed to further improve EECLU. On the premise of protecting the total area of cultivated land, larger and more aggregated land patches should be promoted in the land consolidation process, and the cultivated land targeted for occupation or compensation should be able to simplify the overall shape of cultivated land patches.

Reconfigurable monopole antenna with polarization and pattern diversity

A planar monopole antenna capable of reconfiguring both the polarization and radiation pattern is presented for MIMO systems. A star shape patch is used as the radiator. Four PIN diodes are inserted to control the polarization and radiation pattern. The antenna can operate over two frequency bands. A prototype antenna is designed and fabricated for radiation at 5.5 GHz and 8.4 GHz. The first switching state provides left-hand circular polarization (LHCP) in the first band with the main beam at ϕ = +60° and right-hand circular polarization (RHCP) at 8.4 GHz at ϕ = +140°. For the second switching state, the sense of polarizations changes with the main beam at ϕ = +120° and + 40°, respectively. Measured results show that overlapped bandwidths are obtained from 5.17 to 5.85 GHz at lower band and 8.35 to 8.49 GHz at upper band for both the first and second switching states. For the third switching state, it generates an omnidirectional radiation pattern with linear polarization (LP) over 3.78–5.87 GHz. The antenna possesses the measured peak gain values of 0.65 dBi at lower band and 1.15 dBi at upper band for first and second switching states and an average gain value of 1.1 dBi is obtained for the third switching state. The overall size of the prototype is 24 mm × 23.5 mm on a 1.6 mm thick FR4 substrate. The CP band positions, as well as beam tilt, are tunable. Design guidelines are provided. The demerit of the proposed antenna is that it has achieved lower gain values at dual bands.

Circularly Polarized UWB Antenna with Question Mark Shaped Patch for GPR Applications

A novel Circularly Polarized (CP) Ultra Wideband (UWB) antenna for Ground Penetrating Radar (GPR) applications is presented and discussed in this paper. The proposed antenna is constructed by a question mark shaped radiating patch and a truncated ground plane. A prototype of the designed antenna is fabricated on the FR4-substrate with an overall volume of 0.7λ0×0.793λ0×0.035λ0 at 7 GHz. The simulated results show that the designed antenna has an Impedance Bandwidth (IBW) ranging from 3.14 GHz to 11.88 GHz (116.38%). The CP feature is analyzed and discussed confirming that the antenna maintains a CP radiation characteristic in a broadband with a 3-dB Axial Ratio Bandwidth (ARBW) ranging from 4.13 GHz to 9.28 GHz (76.81%). The measurements were done by utilizing a well calibrated R&amp;S®ZNB Vector Network Analyzer indicating that the fabricated prototype has an IBW nearly ranging from 3.47 GHz to 12.11GHz (110.91%). The results are favorable that ensure the usefulness of this antenna for GPR applications.

Evolution of Ecological Patterns of Poyang Lake Wetland Landscape over the Last One Hundred Years Based on Historical Topographic Maps and Landsat Images

Ecological pattern evolution of Poyang Lake wetland, the largest freshwater lake in China, is critical for regional ecological protection and sustainable development of migratory bird habitats; however, this information is still not fully explored. In this study, we quantitatively reconstructed the spatial distribution and landscape ecological pattern of Poyang Lake wetlands in three periods in the past 100 years based on the military topographic map in the 1930s and the Landsat satellite remote sensing image data in 1979 and 2021. Further, use the Fragstats software to analyze the ecological pattern index of wetland reconstruction results. The results show that the wetland area in the Poyang Lake region has experienced a continuous reduction process over the past 100 years, and it decreased from 3857 km2 in the 1930s to 3673 km2 in the 1970s, and then to 3624 km2 in the 2020s. The current wetland area has decreased by about 6.04% compared with the 1930s. The general trend of changes in the spatial pattern of Poyang Lake wetlands is that the surface water decreases and the open land increases. Nevertheless, the trend has certain spatial differences as a large area of wetlands disappeared in the southwest and west of Poyang Lake and the areas with enlarged wetland density values mainly appeared in the northeastern and northern parts of the study area. The NP (number of patches) in the wetlands of Poyang Lake over the past 100 years showed a downward trend during the 1930s–1970s, and an increasing trend during the 1970s–2010s. Due to the increases of constructed wetlands, the number and density of patches also increased, and PD (patch density) reached a maximum value of 0.142 in 2020s. The LPI (largest patch index) has shown a gradual downward trend in the past 100 years. Compared with the 1930s, the wetlands in 2020s dropped by about 26.64%, and the wetlands further showed a trend of fragmentation. The AI index, which indicates the concentration of wetland patches, reached the maximum value in 2020s, but the LSI (landscape shape index) showed a downward trend in general, indicating that the shape of wetland patches has been simplified over the past 100 years. The research results can provide basic data and decision-making basis for Poyang Lake wetland protection, construction of migratory bird reserve and regional sustainable development.

Magnetic Resonance Imaging Characteristic Evaluation of Dexmedetomidine on Neurocognitive Dysfunction in Elderly Patients with Colorectal Tumors after Laparoscopic Operation.

In order to investigate the effects of Dexmedetomidine (DEX) on postoperative anesthesia recovery time and consciousness function in elderly patients with laparoscopic colorectal tumors, 40 patients (20 in the control group and 20 in the DEX group) were selected. The DEX group was intravenously pumped at a rate of 0.8 μg/kg/h for 10 min and then continuously pumped at a rate of 0.3 μg/kg/h until 40 min before the end of the operation. The two groups were given the same amount of normal saline, with the same way of anesthesia. The results showed that the visual analog scale (VAS) score of pain in the two groups decreased signally. Compared with the control group, the inflammatory factors tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and macrophage inflammatory protein (MIP-2) in the DEX group were remarkably decreased at T1 and T2 stages, with a considerable difference (P < 0.05). One month after the auxiliary diagnosis of colorectal tumor, no clear nodular, irregular shape patches, or patchy diffuse limited points were found, which indicated that the whole tumor had been removed. In summary, DEX could improve postoperative cognitive function in elderly patients who underwent the laparoscopic radical resection of colon cancer, and its mechanism was related to the reduction of inflammatory factors. Therefore, the anesthesia intervention with DEX during the operation had a positive significance for tumor resection.

Optimization of geographical space of ecosystem service areas and land-use planning, Iran.

This study provides a framework for optimizing ecosystem service zones based on landscape patterns. Ecosystem service zoning is a tool for making more informed land-use decisions and integrating ecosystem services into land development strategies. Accordingly, a meta-heuristic algorithm (simulated annealing-genetic hybrid) was applied to optimize zones of three ecosystem services, including aesthetic value, recreation value, and noise pollution reduction service. The goal was to select ecosystem service zones in terms of area, percentage of landscape, shape, and number of patches in two land-use types, including the built-up and green cover. The results indicated that optimum zones based on green infrastructure comprised more extent and average suitability than human infrastructure. The western and southern parts of the target area showed the highest values of ecosystem services for the two land-use classes. The convergence curve of the objective functions indicated the good performance of the employed algorithm in optimizing ecosystem service zones. Overall, the results indicated that optimizing ecosystem service zones based on landscape patterns improved the land-use management framework in the study area. Moreover, the used algorithm allowed for integrating different parameters into ecosystem services zone configurations.

Towards the understanding of wheel-rail flange squeal: In-situ experiment and genuine 3D profile-enhanced transient modelling

Wheel-rail squeal noise during train turning has been a tricky problem influencing passengers and nearby residents. The tonal curve squeal that mainly occurs at the inner rail has been extensively studied, while the broadband flange squeal that takes place at the outer rail that can be equally annoying is seldom mentioned and hardly investigated. This paper presents a study aiming at understanding the mechanism of wheel-rail flange squeal from phenomenon to the underlying source. The study systematically demonstrates the connection between the observed wheel-rail flange squeal noise and contact force, with measurements taken from a series of well-controlled in-situ experiments on an operating metro line, and numerical simulations. An integrated transient model consisting of three submodels on train dynamics, rail dynamics, and wheel-rail contact incorporating genuine 3D surface irregularities is developed specifically for flange squeal analysis. The developed model can reproduce the characteristics of flange squeal and correlates wheel-rail contact force with the flange squeal noise with satisfactory performance. Features of flange squeal under four-speed levels corresponding to in-situ experiments are reappeared from global dynamics to local contact status. An explanation of the generation mechanism of flange squeal is proposed by measurement observation and confirmed through the proposed model with multiple influencing key factors, including train speed, contact position, shape of contact patch, contact creepages, and wheel and rail irregularities. The present study is expected to establish a footstone for the mechanism comprehension of flange squeal and inspire further research in this area.