Rugged Terrain Research Articles

The Geysers Is a Unique Geothermal Resource Presenting Equally Unique Challenges to Drillers

_ For drillers, The Geysers is a unique sort of hell. It is one of the only places on Earth where a shallow well can reach a highly fractured reservoir so hot that it only produces steam. That steam powers 18 power plants generating 835 MW of electricity, making this 45-square-mile area the world’s most prolific geothermal power producer. High drilling costs there also stand out. Drilling a well requires 60 days or so and generates a lot of damaged drill bits and drillpipe. The drilling rigs have the size and power of modern onshore rigs, but a close look reveals there’s no topdrive. Below the rig floor there is a rotary table, known as a Kelly drive because it can spin drilling pipe without being in the line of fire of the steam flowing out when running slotted casing into the steam-production zone. When they get to that zone, they switch from drilling fluid and mud to injecting a high-pressure stream of air because of the enormous fluid losses anticipated when they reach that highly fractured level. A drill bit that lasts 500 ft in this harsh, highly fractured rock has had a long run. And the rugged terrain—mountains to a Texan but hills to a Californian—makes this a hard place to move a rig. “The Geysers is its own animal, for sure,” said Sam Noynaert, a Texas A&M professor who was a key member of a team of drilling experts and scientists that drilled a well in The Geysers to test if faster drilling methods from the oil business could work there. The two upper sections went pretty well, considering. As they went deeper, they repeatedly had to deal with severe fluid losses. Still, they had shaved nearly 6 days off the average drilling time. But when they reached the highly fractured steam-producing payzone and their drilling method changed to air drilling, things got worse with drill bits failing after runs as short as 21 ft. As a Geysers drilling paper presented at the Stanford Geothermal Workshop earlier this year delicately put it: “The air section proved to be more challenging.” The Blob The Geysers has a long history. The heat source is “a large blob of silica-rich magma (which) forced its way through Earth’s crust beneath the Coast Range,” according to the description of an image from NASA. That flow about 1.3 million years ago from deep within the earth heated the overburden, making the rock brittle and prone to fracturing. Over time, water seeped into those hot fissures, creating hot springs that were awed by Native Americans and later attracted tourists to a nearby resort hotel. By the 1960s drillers were tapping the steam in those payzones for commercial power generation, which peaked at 2,000 MW in 1987. It declined from there as steam production depleted the reservoir. Eventually, the output was stabilized at its current level by injecting water from sewage-treatment plants into the production zone.

Spatiotemporal Variability of Soil Erosion in the Pisha Sandstone Region: Influences of Precipitation and Vegetation

The Pisha sandstone area, situated in the upper and middle reaches of the Yellow River in China, is characterized by severe soil and water erosion, making it one of the most critical regions on the Loess Plateau. The rugged terrain and exposed bedrock complicate management efforts for this area, posing challenges for accurate forecasting using soil erosion models. Through an analysis of terrain, vegetation, and precipitation impacts on soil erosion, this study offers theoretical support for predicting soil erosion within the exposed Pisha sandstone area of the Loess Plateau. This has substantial implications for guiding water and soil conservation measures in this region. Focusing on China’s exposed sandstone area within the Geqiugou watershed, temporal and spatial changes in vegetation cover and land use from 1990 to 2020 were analyzed. The result shows that, from 1990 to 2020, the grassland area has exhibited a consistent downward trend, with successive reductions of 64.86% to 59.46%. The area of low vegetation cover witnessed a significant decline of 59.29% in 2020 compared to that in 1990. The moderate erosion area decreased from 84.52 to 57.17 km2. The significant reduction in soil and water loss can be attributed to the expansion of forest and grassland areas, with the implementation of the Grain for Green project serving as a key policy driver for facilitating this expansion. This study provided a good example of combining rainfall with vegetation coverage to fast estimation soil erosion. A mathematical relationship between the vegetation rainfall coupling index (RV) and soil erosion was established with strong fitting effects, enabling estimation of the soil erosion volume under varying slope conditions within Pisha sandstone areas. The main focus of future soil and water conservation in the Pisha sandstone area should be on effectively managing the channel slope and minimizing exposed bedrock areas through a combination of slope cutting, the application of anticorrosive materials, and the implementation of artificial vegetation planting.

Accelerated construction and geometry control of cable-stayed bridge: cable crane method

Mountainous regions with rugged terrain, steep valleys and restricted access to roads and rivers present distinctive challenges for segmented erection of cable-stayed bridges (CSBs). In recent years, the cable crane method (CCM) has emerged as an innovative solution for CSB construction to address the difficulties associated with vertically lifting and horizontally delivering girder segments in such challenging environments. However, integrating the CCM with a CSB introduces a coupling effect, significantly complicating the control of bridge geometry. In this work, the accelerated construction and geometry control for CSBs employing the CCM in mountainous regions were systematically studied. The characteristics of 1521 bridges in mountainous regions were investigated, followed by a numerical analysis of geometry control and field measurements of as-built geometries, forces and ambient conditions during construction. Critical techniques for CSB construction using the CCM are also clarified. The mechanical behaviour of a bridge during construction was comprehensively evaluated to improve geometry control. The numerical results were validated through field measurements, offering valuable insights for future CSB practices using the novel CCM.

A linkage-type self-adaptive deformable tracked mechanism based on the six-bar mechanism

Abstract. In order to design a self-adaptive tracked mechanism that can passively adjust according to the height of different obstacles to improve its obstacle-crossing performance, this paper proposes a linkage-type self-adaptive deformable tracked mechanism. The mechanism based on the planar six-bar mechanism is proposed, and its motion modes and obstacle-crossing capabilities are analyzed. Firstly, based on the characteristics of self-adaptive deformation and the planar six-bar mechanism, a deformable single-degree-of-freedom (DOF) multi-loop mechanism is designed by limiting the DOF and adjusting the link lengths, and subsequently, a linkage-type self-adaptive deformable tracked mechanism module is designed according to the multi-loop mechanism. Secondly, the movement characteristics of the deformable tracked mechanism module are analyzed, and it is obtained that the tracked mechanism has two modes of movement: forward and reverse. These modes include deformable tracked-type obstacle crossing and rocker-arm-type obstacle crossing, respectively. Additionally, it is also obtained that this mechanism is capable of climbing up and descending down slopes. Finally, a prototype model is designed for experimental verification to verify the correctness of the theoretical analysis of the linkage-type self-adaptive deformable tracked mechanism and the feasibility of the obstacle-crossing modes. The results indicate that the linkage-type self-adaptive deformable tracked mechanism is capable of various obstacle-crossing modes, including both forward and reverse movements. These modes encompass the traditional tracked type, the deformable tracked type, and the rocker-arm type, as well as the ability to climb up and descend down slopes. This type of mechanism demonstrates excellent terrain adaptability and is capable of overcoming obstacles, allowing it to traverse some soft and rugged terrain. Consequently, it holds certain application potential.

The surface downward longwave radiation of the CMIP6 HighResMIP in East Asia offline corrected by the three-dimensional sub-grid terrain longwave radiative effect scheme

Abstract Terrain significantly regulates surface downward longwave radiation (SDLR). The CMIP6 HighResMIP models without the three-dimensional sub-grid terrain longwave radiative effects (3DSTLRE) produce large SDLR biases over complex terrains. This study applies the 3DSTLRE scheme to correct the SDLR simulated by these models in East Asia and assesses the correction’s effectiveness. Results indicate that the CMIP6 HighResMIP models without the 3DSTLRE clearly underestimate the SDLR over the rugged terrains and the underestimation increases with the sub-grid terrain complexity. The offline correction of 3DSTLRE can evidently improve the SDLR simulations in different seasons, and the improvements increase with the sub-grid terrain complexity. The most significant improvements are observed over the Himalayas, the Tibetan Plateau, the Tianshan Mountains, and the Hengduan Mountains. The relative root mean square error of SDLR simulations over the areas with the most complex sub-grid terrains can be decreased by ∼40% due to the offline correction of 3DSTLRE. Considering the 3DSTLRE may be an efficient way to improve the simulations of the SDLR and surface energy balance over the regions with complex sub-grid terrains.

Lightning Casualties of Vulnerable Caterpillar Fungus Collectors on the Qinghai–Tibetan Plateau

Abstract Lightning has killed and injured many people in recent years in the Qinghai–Tibetan Plateau area of China when they were collecting a rare product used for medical applications. The fungus that grows on dead caterpillars at high altitudes in this region demands a high price when sold, so it attracts collectors that unfortunately become at risk from lightning during this process. A total of 12 lightning-related events during 2004–22 resulted in 29 deaths and 53 injuries. All cases occurred at high elevations in rugged terrain with no available lightning-safe structures or vehicles. The fungus collection occurred during the daytime hours in late spring and early summer, which is also when lightning is frequent. Maps of lightning for the cases and information gained from the Chinese-language reports are summarized. It is apparent that this is a unique high-risk, high-reward occupation that is similar in terms of exposure to other situations around the world that result in lightning deaths and injuries. Significance Statement Lightning deaths and injuries often occur when people push the limits of safety due to occupational or recreational demands. Most of these decisions are on short time scales such as while tending agricultural fields, working on roofs, running a competitive race, or walking home from school when a thunderstorm is approaching. In the scenario presented here, groups of people with few income alternatives spend weeks or months in mountainous regions where lightning is common, but safety is elusive. This situation is an unusual version of high lightning risk occurring while pursuing a high reward.

Tracking Small Animals in Complex Landscapes: AComparison of Localisation Workflows for Automated Radio Telemetry Systems.

Automated radio telemetry systems (ARTS) have the potential to revolutionise our understanding of animal movement by providing a near-continuous record of individual locations in the wild. However, localisation errors in ARTS data can be very high, especially in natural landscapes with complex vegetation structure and topography. This curtails the research questions that may be addressed with this technology. We set up an ARTS grid in a valley with heterogeneous vegetation cover in the Colombian high Andes and applied an analytical pipeline to test the effectiveness of localisation methods. We performed calibration trials to simulate animal movement in high- or low-flight, or walking on the ground, and compared workflows with varying decisions related to signal cleaning, selection, smoothing, and interpretation, along with four multilateration approaches. We also quantified the influence of spatial features on the system's accuracy. Results showed large variation in localisation error, ranging between 0.4-43.4 m and 474-1929 m, depending on the localisation method used. We found that the selection of higher radio signal strengths and data smoothing based on the temporal autocorrelation are useful tools to improve accuracy. Moreover, terrain ruggedness, height of movement, vegetation type, and the location of animals inside or outside the grid area influence localisation error. In the case of our study system, thousands of location points were successfully estimated for two high-altitude hummingbird species that previously lacked movement data. Our case study on hummingbirds suggests ARTS grids can be used to estimate small animals' home ranges, associations with vegetation types, and seasonality in occurrence. We present a comparative localisation pipeline, highlighting the variety of possible decisions while processing radio signal data. Overall, this study provides guidance to improve the resolution of location estimates, broadening the application of this tracking technology in the study of the spatial ecology of wild populations.

Landslide susceptibility assessment along highways (SH-12 and NH-717A) in Darjeeling Himalayas

Landslides are the utmost damaging natural along with anthropogenic hazards which cause huge damage to assets and human lives in hilly environments all over the world. The key aim of this study is to explore landslide susceptibility (LS) maps along highways (SH-12 and NH-717A) in the Darjeeling Himalayas, India. Four data-driven bivariate statistical models (BSMs) were used to develop LS maps based on geospatial techniques. A total of 90 (100%) polygons with different size of landslide locations were identified to develop landslide inventory/distribution (LI/LD) map by incorporating Google Earth and satellite imageries, and filed investigation through the global positioning system (GPS). The LI/LD map is distributed into testing 30% (27 landslide locations), and training 70% (63 landslide locations) of the models. Eighteen landslide causative factors (LCFs) were selected to develop LS maps. Multicollinearity analysis showed that there is no collinearity problem in the LCFs. The receiver operating characteristics (ROC) curve and frequency ratio (FR) value techniques were applied for validation. The relative importance of each LCF for each model has been measured using Jack-knife test. The LS maps were divided into six landslide susceptibility zones (LSZs). The ROC curve showed the accuracy of the LSZ maps is 93.50% for FR, 85.90% for evidential belief functions (EBFs), 81.80% for fuzzy membership (FM) using FR, and 77.20% for FM using cosine amplitude (CA) approaches respectively. Among all models, the FR model showed the highest percentage of accuracy for LS assessment and prediction. The FR values of six LSZs rise from very low to very high LSZs which indicate a positive correlation between LSZs and FR values. The results of Jack-knife test showed that terrain ruggedness index (TRI) factor has the highest relative importance for all models in LSZ mappings. The study findings will help to the planner, and policymakers for spatial planning, implement slope management strategies, land use management in mountainous environments.

The Impact of Government Data Accessibility on Cross-Regional Venture Capital Investments

This study examines the association between government data accessibility and venture capital (VC)'s cross-regional investments. Exploiting the staggered establishment of government data open platforms (GDOPs) across different cities in China as a positive shock to government data accessibility, we find that this policy significantly increases cross-regional VC investments in treatment cities relative to others. Furthermore, the positive impact is achieved through the reduction of information asymmetry, as the establishment of GDOPs attracts VC investments from greater geographical distances. Additionally, we find a more pronounced positive effect of GDOPs on promoting cross-regional VC investments in regions with higher terrain ruggedness and lower fiscal transparency. Overall, this study demonstrates that the government's informatization and transparency initiatives can positively influence financial markets by enhancing the cross-regional flow of financial capital.

Vegetation cover, topography, and low-traffic roads influence Sonoran desert tortoise (Gopherus morafkai) movement and habitat selection

BackgroundAnthropogenic activities occurring throughout the Sonoran Desert are replacing and fragmenting habitat and reducing landscape connectivity for the Sonoran desert tortoise (Gopherus morafkai). Understanding how the structure of the landscape influences tortoise habitat use and movement can help develop strategies for mitigating the impacts of these landscape alterations, which are conservation actions needed to support the species’ long-term persistence. However, how natural and anthropogenic features influence fine-scale habitat use and movement of Sonoran desert tortoises remains unclear.MethodsThe goals of this study were to (1) understand how characteristics of the landscape shape tortoise habitat use and movement in order to (2) identify factors that may reduce habitat use or threaten landscape connectivity for the species by discouraging or restricting movement. We collected GPS telemetry data from 17 adult tortoises tracked for two summer monsoon seasons, when tortoises are most active, in a U.S. National Monument along the international border between Arizona, USA and Sonora, Mexico. We used Hidden Markov Models (HMMs) to assign GPS locations to an encamped or a moving state. We used the moving state data in integrated Step Selection Analyses (iSSA) to examine how range-resident Sonoran desert tortoises select habitat and respond to landscape features while moving.ResultsTortoises selected to move through areas of intermediate vegetation cover and terrain ruggedness and avoided areas far from desert washes and close to low-traffic roads. Tortoises increased their speed when approaching or crossing low-traffic roads but showed no detectable response to a highway.ConclusionBare earth or high vegetation cover, flat or extremely rugged terrain, areas far from desert washes, and low-traffic roads may discourage or restrict tortoise movement. Therefore, preventing the development of roads, activities that degrade washes, and activities that thin, remove, or greatly increase vegetation cover may encourage tortoise habitat use and movement within those habitats.

Resource selection of den sites for bobcats (Lynx rufus) in the Northern Great Plains, United States

Abstract Dens play a crucial role in the survival of young and can ultimately affect population dynamics for felid carnivores. However, little is known about Bobcat (Lynx rufus) den site selection. Therefore, this study aimed to identify environmental correlates of Bobcat den sites in the Black Hills, South Dakota, United States. Our objectives for this study were to compare environmental characteristics of Bobcat dens to random sites at coarse (3.14 ha) and local (0.05 ha) spatial scales. Female bobcats were radio-collared (n = 35) and dens (n = 27) were located using ground telemetry. Bobcats selected for high horizontal cover and terrain ruggedness at the coarse scale, as well as high horizontal cover at the local scale, which could provide concealment from predators. In less rugged areas land management practices that promote increased tree and shrub habitat as horizontal cover may provide habitat for Bobcat dens and ensure the survival of this ecologically and culturally important species.

Mortality Risk Factors in Appalachian Burn Patients: A 13-Year Retrospective Study.

Introduction Burn injuries pose a significant public health challenge globally, with Appalachia facing unique obstacles due to its rugged terrain, economic disparities, and limited access to healthcare. Understanding mortality risk factors specific to Appalachian burn patients is crucial for optimizing treatment approaches in this underserved population. Materials and methods A retrospective analysis of burn patient data from Cabell Huntington Hospital's burn intensive care unit (BICU) over 13 years was conducted. Patient recordswere reviewed, and demographic and clinical variables were analyzed using descriptive statistics and logistic regression models. Results Among 1,104 Appalachian burn patients treated at Cabell Huntington Hospital's BICU between January 2010 and June 2023, advanced age, larger total body surface area (TBSA) burned, inhalation injuries, chronic obstructive pulmonary disease (COPD), and third-degree burns were significant predictors of mortality. Advanced age (p < 0.001, OR: 1.07), larger TBSA burned (p < 0.001, OR: 1.1), inhalation injuries (p < 0.001, OR: 8.34), COPD (p < 0.001, OR: 2.64), and third-degree burns (p < 0.001, OR: 6.45) were significant predictors of mortality. Gender, smoking history, diabetes mellitus (DM), and body mass index did not significantly differ between survivors and deceased patients. Discussion/conclusion Our findings underscore the importance of tailored interventions for Appalachian burn patients. Advanced age, pre-existing comorbidities, and burn severity significantly impact mortality risk, emphasizing the need for comprehensive care strategies. Specialized burn centers play a critical role in managing complex burn injuries in underserved regions. Addressing mortality risk factors identified in this study is essential for optimizing burn care outcomes in Appalachia. Tailored interventions and collaborative efforts are needed to improve survival rates and promote health equity for burn patients in underserved regions. Future research should explore additional factors influencing burn outcomes and assess disparities in access to specialized care services.

Can wild urban woodlands be integrated into urban green infrastructure? Insights from urbanites and new urbanites in Chongqing, China

Wild urban woodlands (WUWs) are a novel category of urban forests and have been established as vital sources of diverse ecosystem services for local residents. Despite their potential to mitigate green gentrification, WUWs are often neglected in urban planning. Assessing whether different groups of residents accept WUWs as a part of urban green spaces and determining their preferred WUW type are critical for cities lacking green space supply. Therefore, a collection of photographs of 15 WUW patches was employed in this study to explore the preferences and attitudes of urbanites (n = 200) and new urbanites (i.e., individuals who have undergone a transition from rural to urban residency due to urban expansion; n = 206) toward five prevalent WUW categories and examine their perspectives on the future transformation of these WUWs. Accordingly, the following study results were obtained. (1) New urbanites exhibited greater support for integrating WUWs into urban green infrastructure compared to urbanites, primarily due to the limited supply of green spaces in their residential surroundings. (2) The one-way ANOVA shows significant differences in WUW preference scores between new urbanites and urbanites. Urbanites strongly preferred WUWs situated within stream corridors and the least for WUWs in urban villages. Conversely, new urbanites preferred WUWs on agricultural lands and found WUWs on industrial lands the least appealing. (3) Most participants expressed a desire to witness the planned transformation of WUWs. New urbanites preferred additional spaces for leisure activities, whereas urbanites hoped to witness visual improvements in the WUWs. (4) Multifactor ANOVA shows rural background significantly affects preferences scores. Spearman correlation indicates terrain ruggedness and surrounding construction intensity relate to preference. These findings underscore the substantial potential of WUWs in the urban greening in China. They contribute to urban managers' understanding of the diverse needs of the two urban resident groups regarding WUWs, thereby fostering equity in green space planning.

Application of fallout radionuclide—137Cs for estimating soil erosion in steep hillslopes with diverse land use of North-western Indian Himalayas

Hilly and mountainous regions are significantly impacted by soil erosion, primarily due to rainfall-runoff processes occurring on the hillslope scale. Assessing soil erosion is crucial for quantifying the loss of soil carbon and nutrients, which diminishes the potential of soil ecosystem services and is critical for mitigating the impacts of climate change on food security. However, the Himalayan landscape poses serious challenges for assessing soil erosion due to its steep and rugged terrain, which hinders the use of conventional and modelling methods. The fallout radionuclide—137Cs has been extensively utilized as an environmental marker for investigating soil redistribution processes. Despite its potential, there is a notable lack of 137Cs-based soil erosion studies in the Himalayan region. In this context, we assessed the applicability of the fallout radionuclide—137Cs method in quantifying soil erosion rates and identifying erosion hotspots on two hillslopes of the Higher Himalayas. On the hillslope scale, we observed that soil erosion rates vary based on slope gradient and land use/land cover. Forested areas exhibited the lowest soil erosion rates compared to cultivated areas, while flat hillslope positions experienced lower erosion rates than steeper positions. The average net erosion rate for the Harsil hillslope varied among different hillslope positions, ranging from – 2.9 to – 15.6 t ha−1 yr−1. Similarly, in the Gangnani hillslope, the net erosion rates varied across different positions, ranging from – 5.6 to – 39 t ha−1 yr−1. Our findings confirm that the middle and lower hillslope positions are the most critical source areas with higher soil erosion rates, while hillslope positions with forest cover demonstrate the lowest erosion rates, identified as helpful in controlling soil erosion. The study has demonstrated the applicability of FRN as a soil erosion measurement method in the complex, rugged, and steep terrain of the Himalayas, highlighting the need for targeted conservation efforts to mitigate soil erosion and preserve ecosystem integrity.

Land degradation vulnerability mapping using geospatial techniques: a case study of Nandakini River basin, NW Himalaya, India

ABSTRACT Land degradation is a significant global environmental issue, and its prevention has become a serious concern of the twenty-first century, particularly in the context of anthropogenic impact and climate change. It is crucial to map and assess the grade of land degradation to determine vulnerable areas. The Indian Himalayan region faces heightened risks with its steep terrain, active tectonics, heavy precipitation, and human interventions. This study focuses on the Nandakini Watershed. Employing AHP technique, the study calculates the Land Degradation Vulnerability Index (LDVI) using slope, terrain ruggedness, rainfall, temperature, LULC, soil depth, and organic carbon content. The results indicate that the upper region is highly vulnerable, and a higher slope influences the runoff in the area, followed by factors like NDVI and rainfall, collectively contributing to 62% of the overall index. In this context, the upstream regions of the watershed display a high LDVI, while most of the area falls within the low LDVI category. This indicates that approximately 2.10% of the study area is highly susceptible to soil erosion. RUSLE-based estimates have been used to further validate the LDVI result. The integrated LDVI offers a valuable tool for prioritising soil conservation and disaster mitigation.

Morphometry of the Mt Manengouba volcano: Insights into tephrostratigraphy of Eboga maars (South West Cameroon)

The GIS-based geomorphological and morphometric approaches were combined with field- and tephrostratigraphic analyses to reconstruct the history of the Mt Manengouba volcano including the Eboga maars in the southwestern part of the Cameroon Volcanic Line (CVL). The elevation, slope, relative relief, topographic position and terrain ruggedness indexes from the Digital Elevation Model (DEM, 12.5 m) were determined to constrain two main geomorphic units corresponding to the Elengoum and Eboga nested stratovolcanoes which were affected by differential erosional processes. The studied grain size, shape, vesicularity, structure, degree of lithification, sorting, thickness, grading patterns, sedimentary features, spatial distribution revealed three tephrostratigraphic units: U1 (U1-1, lithic and juvenile; U1-2 dominantly juvenile), U2 (U2-1 ash- and juvenile rich-deposits; U2-2, juvenile-scoria with few lithic) and U3 (scoria cone deposits). The total volume of ∼0.199 km3 of tephra deposits ranges the Eboga maars volcanoes within the small-volume monogenetic types. These results revealed dry/wet phreatomagmatism and strombolian activity as a contribution to the seven phases-eruptive history of the Mt Manengouba volcano: the pre-Manengouba; emplacement of Elengoum stratovolcano; collapse of Elengoum summit and formation of Elengoum caldera; emplacement of Eboga stratovolcano; the collapse of Eboga summit and formation of Eboga caldera; a phreatomagmatic phase and emplacement of Female and Male maars ending with an explosive stage associated with the formation of scoria and parasitic cones.

Working space planning for wheeled robot overturning stability

Abstract Mobile manipulators have been widely used in the field of building construction. Typical features of construction robots include crossing various rugged terrains in construction sites, carrying heavy payloads, and performing tasks in a large workspace, which may lead to unstable posture or overturning. The tipping of the mobile manipulator, especially when carrying a payload, will cause danger to the surrounding environment and staff, leading to the termination of the task. The purpose of this study is to establish a real-time tipping prediction system, which can be used to avoid tipping of mobile manipulators. By employing the CAD model of the robot and parameters such as the center of gravity and direction, we can ascertain and assess the instability of the robot and the overturning algorithm, thus providing early warning and averting any potential danger.

Identifying long-term burned forests in the rugged terrain of Southwest China:A novel method based on remote sensing and ecological mechanisms

Burned forests were detected using remote sensing techniques. Yet, identifying long-term burned forests in the mountains, especially at a large spatial extent, remains a great challenge due to a lack of long-term high-resolution remote sensing data or the unsatisfactory performance of the moderate-resolution remotely sensed data in complex mountain landscapes. Efficient, robust, and cost-effective methods are urgently called for. In this study, we developed a novel method combining remote sensing and ecological mechanisms (short for RSEM-M) with a paired-pixel approach to identify the long-term burned forests in Southwest China, where the terrain is rugged. In mapping burned forests in 2010, the overall accuracy, producer accuracy, user accuracy, Kappa coefficient, and field validation accuracy were 92.27 %, 95.86 %, 88.36 %, 0.85, and 81.16 %, respectively. Compared to the standard procedure and FireCCI51 and MCD64A1 fire products, the RSEM-M shows higher accuracy and consistency in identifying burned forests of different sizes, with fewer invalid pixels, better spatial continuity, and more accurate boundary delineation. Then, using the RSEM-M, we mapped burned forests in Southwest China from 2002 to 2017. The cumulative areas were 37.69 × 104 ha. The RSEM-M improved the efficiency and accuracy of long-term burned forest identifications in mountainous landscapes at a large spatial extent.

A composite motion control method for quadruped robots in trot gait

This work aims to address the issues of instability in trot gait walking and poor terrain adaptability in rugged environments under conventional control strategies for quadruped robots by proposing a novel composite control strategy. During the support phase, a separated force-position mixing control method is employed, utilizing gravity-compensated PD (Proportional Derivative) control at the lateral swing and knee joints while employing position control at the hip joint. During the swing phase, VMC (Virtual Model Control) is used to construct three sets of virtual spring-damper components, guiding the foot to move along a predetermined trajectory and converting virtual forces into joint torques for the swinging leg. At the body, IMU (Inertial Measurement Unit) feedback data combined with PI (Proportional Integral) control is used to adjust leg length and maintain the robot’s posture stability. Finally, the proposed separated force-position hybrid control method is theoretically validated using the Lyapunov stability criterion, and simulation tests on flat and rugged terrains under the quadruped robot’s composite control method are conducted using MATLAB/Simulink, comparing it with the VMC and position control methods. The findings indicate that the composite control strategy leads to smaller changes in the attitude angles and reduced impact forces at the feet during the quadruped robot’s walk on flat ground while also demonstrating strong adaptability to rugged terrains.

Landslide Risk Assessments through Multicriteria Analysis

Natural risks comprise a whole range of disasters and dangers, requiring comprehensive management through advanced assessment, forecasting, and warning systems. Our specific focus is on landslides in difficult terrains. The evaluation of landslide risks employs sophisticated multicriteria models, such as the weighted sum GIS approach, which integrates qualitative parameters. Despite the challenges posed by the rugged terrain in Northern Algeria, it is paradoxically home to a dense population attracted by valuable hydro-agricultural resources. The goal of our research is to study landslide risks in these areas, particularly in the Mila region, with the aim of constructing a mathematical model that integrates both hazard and vulnerability considerations. This complex process identifies threats and their determining factors, including geomorphology and socio-economic conditions. We developed two algorithms, the analytic hierarchy process (AHP) and the fuzzy analytic hierarchy process (FAHP), to prioritize criteria and sub-criteria by assigning weights to them, aiming to find the optimal solution. By integrating multi-source data, including satellite images and in situ measurements, into a GIS and applying the two algorithms, we successfully generated landslide susceptibility maps. The FAHP method demonstrated a higher capacity to manage uncertainty and specialist assessment errors. Finally, a comparison between the developed risk map and the observed risk inventory map revealed a strong correlation between the thematic datasets.