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the paper deals with the case when particles are evenly distributed in ravines, using the equilibrium coefficient to update the particle velocity. the method of optimizing a swarm of particles in the case of a \"ravine\" is one of the most effective approaches for multi-extremal optimization. however, in the existing methods of optimizing the swarm of particles with the \"ravine\" methods, the number of particles around the ravine is very different from each other, which makes it difficult to find high-quality algorithms in all the ravines. thus, the computational resources are distributed in the ravines in a more balanced way.

Since lots of underground and slope excavation works were conducted during the urbanization process, an increasing number of sites in ravines around a city have been used to stockpile a large amount of excavated soils. This brings a huge challenge for researchers and managers in the risk evaluation and mitigation of potential dangers of these man-made construction waste landfills. This paper describes a recently large landslide of the construction waste landfill, which occurred at a site of Guangming new district in Shenzhen, China, on December 20, 2015. This catastrophic landslide caused the death of 69 persons and 8 persons are still missing. In this paper, this landslide was numerically simulated and analyzed. In spite of neither high-intensity rainfall nor antecedent rainfall, a slope of this landfill with a relative height of 111 m sided and caused about 2.34 million cubic meters of the soils to travel over a gentle terrain more than 1.2 km. This means that the landslide mobility index (H/L = 0.092) is much lower than a general designed value and the values in most other cases. A depth-integrated continuum method and a MacCormack-TVD finite difference algorithm are adopted, in this paper, to numerically simulate the dynamic process of this large landslide. It is found that a Coulomb friction model with consideration of the pore water pressure effects can well reproduce the main characteristics of the dynamic process of this landslide. Sensitivity analysis has demonstrated that the high pore water pressure in the soils plays a significant role in its mobility and is a key factor to the severity of this landslide.

The Trondheim and Gauldal areas in Mid-Norway are characterized by thick marine deposits from the ice age and deglaciation period. The following glacio-isostatic rebound has led to river incisions in the valleys and extensive landsliding and ravine erosion. This study is based on data from an upgraded Quaternary geological map of this region for the areas below the highest sea level after the last ice age, with a focus on landslide scars and ravines. The study has a multidisciplinary approach, which is important in order to get a good regional geological understanding of the ground conditions and the landscape development. This means that geological, geomorphological, geotechnical, geophysical and hydrogeological data are used. The study area is divided into six parts, based on natural topographical divisions and the distribution of landslide scars and ravines. Factors influencing the development of sensitive clay and the triggering of landslides are described for each area; these include sediment distribution, thicknesses and stratigraphy, bedrock topography, the degree of leaching of clay, groundwater conditions, the number, size and shape of landslides, and the distribution of rivers, streams and ravines. The study shows that the size, behaviour and erosional potential of the main river or stream influence the landscape development to a high degree. The erosional basis, stratigraphy and presence of bedrock are essential for leaching and the development of quick clay.

This research investigates geohazards and preventative countermeasures for Lanzhou City, China. To investigate the factors related to the development of geohazards in Lanzhou, the regional geological conditions around Lanzhou were investigated. The geomorphology of the region is comprised of a loess landform underlying quaternary loess deposits. A large number of faults induced by strong neotectonic movements are present in the area. Therefore, earthquakes frequently occur around Lanzhou. Earthquakes cause numerous rock falls and landslides, with landslide masses found scattered on the upper middle level of the area’s mountains. When intense rainfall occurs, a lot of loose deposits are brought together along steep gullies, forming debris flows; hence, a disaster chain of earthquake–landslide–debris flow is formed. To evaluate the georisks around Lanzhou, the Analytic Hierarchy Process (AHP) was employed to assess geohazards. The spatial distribution of the evaluated georisk levels was mapped using a Geographic Information System (GIS). Based on the assessed results, about 55% of the urban area and 44% of Gaolan County have high or very high-risk levels. The ratio of relatively high disaster risk levels is up to 31% of the total area. To mitigate these geohazards, both strategic decision making and technical countermeasures should be implemented.

The urban ravines of Moyobamba, despite being considered natural spaces, are fundamental spaces for citizen participation, related to a sociocultural issue of local identity, social interaction and community welfare. Despite this, their current state has been affected, which could lead to a negative perception of the uses of these spaces. Therefore, this research analyzes the articulation of the cultural ecosystem services (CES) of the ravines and their level of conservation and through a mixed method, combining quantitative and qualitative approach, through semi-structured interviews to residents and experts on the subject of conservation of the ravines and the perception of their valuation was evaluated, in addition, through direct observation and documentary review, the analysis of their current physical state was made. It was found that the residents who live near the ravines or make use of them, value these spaces for a sense of relevance, promoting social interaction that offer opportunities for ecotourism and recreational activities. However, it was identified that the physical condition presents moderate and severe environmental deterioration, which has reduced the influx of visitors and the quality of the residents' experience. The results show that the ravines should be preserved for their ecological, cultural and social condition. The loss of spatial quality limits activities and reduces the positive impact of community participation. It is recommended that public conservation policies be strengthened to increase public awareness to ensure the valuation of these ecosystems and the legacy for future generations.

The loess hilly and gully areas have broken terrain, vertical and horizontal ravines and fragile ecological environments. Improving the resilience of the regional ecological space is conducive to improving the quality of the local ecological environment. With the ecological space of the Yanhe River Basin selected as the research object, this paper constructs a research framework of \"network identification topology-resilience evaluation-spatial optimization\" and uses morphological spatial pattern analysis (MSPA) and the minimum cumulative resistance model (MCR) to identify ecological spatial networks. Based on circuit theory, the ecological pinch point is identified, the ecological spatial network is optimized, and scenario simulation is performed. Through complex network theory and related indicators, the ecological spatial resilience of the basin is evaluated, and the hierarchical optimization strategy of the ecological space is confirmed. According to the ecological function of the source area and the results of the resilience evaluation, the boundaries of the protected control area, guidance development area, remediation area, and maintenance and improvement area of the basin are delineated. The importance of ecological source and corridor protection is classified, and corresponding protection strategies are proposed. The research results can provide theoretical support and practical guidance for the territorial spatial planning and ecological space construction of the Yanhe River Basin and provide a reference for the ecological restoration, resource development and environmental governance of the Yanhe River Basin.

Aim Geodiversity underpins biodiversity, but the contribution of specific geofeatures or landforms has rarely been explored. In this study, we use multiple vascular plant species diversity measures on alpha, beta and gamma levels to explore the linkage between biodiversity and co‐located landforms (e.g. gullies, dunes and lake shores). We hypothesize that biodiversity will be positively related to geodiversity, which is founded on distinct landforms. Additionally, we propose that different landforms will sustain different amounts of biodiversity and that high alpha and gamma diversity values are related to landform‐driven moisture availability whereas high beta diversity relates especially to landform‐specific microtopographic variation. Location Rokua UNESCO Global Geopark area, Finland. Taxon Vascular plants. Methods We compare vascular plant species richness measures, Shannon's and Simpson's diversity indices, rarity‐weighted richness and local contribution to beta diversity at altogether three levels of biodiversity (alpha, beta and gamma) for different landforms. Landform information is compiled from aerial photos, spatial data layers and targeted field surveys. We compare results to control habitat (i.e. sites without any distinct landforms) within the study area. Results Vascular plant diversity was higher on landforms than in control habitat. There was also notable variation between species diversity of different landforms. Moisture‐rich gullies and river shores were especially diverse at all three levels, whereas aapa mires hosted most unique species composition (highest beta diversity). Beta diversity patterns were rather comparable with alpha and gamma diversity patterns, which contradict our hypothesis. Main conclusions This study quantitatively established a strong connection between terrestrial plant communities and multiple landforms. Our results highlighted the landform‐controlled variation in soil moisture, microclimate and microtopography in enhancing plant species diversity. Based on the results, we promote the inclusion of landform‐based geodiversity information in conservation management and in further biogeographical studies.

Silver lime is a thermophilic, calciphile species that thrives in xero-mesophilic forest communities. The westernmost edge of its natural distribution is Zrinska Gora Mountain in central Croatia, where it is found in almost all types of forest vegetation, albeit with varying frequencies. Its ecological optimum is in specific ravines and grooves, where it forms the mesophilic, relict broad-leaved ravine forest community Polysticho setiferi-Tilietum tomentosae. This research was conducted on two levels. Firstly, the communities of Zrinska Gora were analyzed as the westernmost edge of the natural distribution. Secondly, the ecology of the Tilia tomentosa communities in the western part of its distribution (Croatia, Bosnia and Herzegovina, Hungary, and Serbia) was observed. Analysis of Ellenberg-type indicator values for 74 communities from the western Balkans revealed a slight trend of decreasing thermophilicity and increasing acidophilicity toward the western edge of the distribution area. Silver lime peripheral populations on Zrinska Gora develop under unique ecological conditions. The soil reaction of all communities falls below the lower limit of the optimal range for its development, and the relict association experiences lower temperature values compared to the other communities. All in all, the results of this study provide insights into the adaptability of silver lime to climate change.

The catalyst microstructure significantly impacts the corresponding hydrodesulfurization (HDS) performance. In this study, the carbon sponge (CMF) derived from melamine foam was used as support to prepare a series of pre-sulfurized CoMoS/CMF catalysts with different Co/Mo molar ratios using hydrothermal synthesis. The characterization results from SEM, TEM, XRD, and N 2 physisorption revealed that all catalysts exhibit the three-dimensional porous (3DP) structure, where the metal sulfides with uneven ravines coated the CMF framework. The optimized Co 2.0 MoS/CMF catalyst achieved 99.2% thiophene conversion at 1 MPa and 360 °C during HDS test. The interconnected pores facilitated the reactant/product diffusion in the catalyst. Moreover, the highly dispersed MoS 2 provided abundant active sites, leading to enhanced HDS activity. This study demonstrates the promise of CMF support for developing pre-sulfurized catalysts with enhanced HDS activity. Graphical Abstract