Assessment on eco-environmental quality of the Yellow River Basin by considering desertification index

Desertification has had a significant impact on the ecological environment of the Yellow River Basin(YRB)in China.However,previous studies on the evaluation of the ecological environment quality(EEQ)in the YRB have paid limited attention to the indicator of desertification.It is of great significance to incorporate the desertification index into the spatiotemporal assessment of the EEQ in the YRB in order to protect the ecological environment in the region.In this study,based on multi-source remote sensing data from 91 cities in the YRB,this article proposes a desertification remote sensing ecological index(DRSEI)model,which builds upon the traditional Remote Sensing Ecological Index(RSEI)model,to analyze the spatiotemporal changes in the EEQ in the YRB from 2001 to 2021.Furthermore,using the geographic detector(GD),and geographically and temporally weighted regression(GTWR)model,the study assesses the impact of human and natural factors on the EEQ in the YRB.The research findings indicate that:(1)Compared to the traditional RSEI,the improved DRSEI shows a decreasing trend in the evaluation results of the EEQ.Among the 24 cities,the change in DRSEI exceeds 0.05 compared to RSEI,accounting for 26.37%of the YRB.The remaining 67 cities have changes within a range of less than 0.05,accounting for 73.63%of the YRB.(2)The results of the GD for individual and interactive effects reveal that rainfall and elevation have significant individual and interactive effects on the EEQ.Furthermore,after the interaction with natural factors,the explanatory power of human factors gradually increases over time.The spatial heterogeneity results of GTWR demonstrate that rainfall has a strong direct positive impact on the EEQ,accounting for 98.90%of the influence,while temperature exhibits a more pronounced direct inhibitory effect,accounting for 76.92%of the influence.Human activities have a strong negative impact on the EEQ and a weak positive impact.

Torsional vibration suppression and electromechanical coupling characteristics of electric drive system considering misalignment

The torque ripples resulting from external electromagnetic excitation and mechanical internal excitation contribute to significant torsional vibration issues within electromechanical coupling systems.To mitigate these fluctuations,a passive control strategy centered around a multi-stable nonlinear energy sink(MNES)is proposed.First,models for electromagnetic torque,gear nonlinear meshing torque,and misalignment torque are established.Building upon this foundation,an electromechanical coupling dynamic model of the electric drive system is formulated.Sensitivity analysis is conducted to determine the sensitive nodes of each mode and to provide guidance for the installation of the MNES.The structure of the MNES is introduced,and an electromechanical coupling dynamic model with the MNES is established.Based on this model,the influence of the misaligned angle on the electromechanical coupling characteristics is analyzed.In addition,the vibration suppression performance of the MNES is studied under both speed and uniform speed conditions.Finally,experimental testing is conducted to verify the vibration suppression performance of the MNES.The results indicate that misalignment triggers the emergence of its characteristic frequencies and associated sidebands.Meanwhile,the MNES effectively mitigates the torsional vibrations in the coupled system,demonstrating suppression rates of 52.69%in simulations and 63.3%in experiments.

Review of Fault-tolerant Control for Motor Inverter Failure with Operational Quality Considered

In recent years,motor drive systems have garnered increasing attention due to their high efficiency and superior control performance.This is especially apparent in aerospace,marine propulsion,and electric vehicles,where high performance,efficiency,and reliability are crucial.The ability of the drive system to maintain long-term fault-tolerant control(FTC)operation after a failure is essential.The likelihood of inverter failures surpasses that of other components in the drive system,highlighting its critical importance.Long-term FTC operation ensures the system retains its fundamental functions until safe repairs or replacements can be made.The focus of developing a FTC strategy has shifted from basic FTC operations to enhancing the post-fault quality to accommodate the realities of prolonged operation post-failure.This paper primarily investigates FTC strategies for inverter failures in various motor drive systems over the past decade.These strategies are categorized into three types based on post-fault operational quality:rescue,remedy,and reestablishment.The paper discusses each typical control strategy and its research focus,the strengths and weaknesses of various algorithms,and recent advancements in FTC.Finally,this review summarizes effective FTC techniques for inverter failures in motor drive systems and suggests directions for future research.

Research on X-by-Wire Chassis Technology for Intelligent Driving of New Energy Vehicles

As China’s economy develops,new energy technologies and intelligent driving have become a trend in the automobile industry.The development of new energy vehicles has accelerated,with X-by-wire chassis technology becoming the core technology for intelligent driving.This technology includes steer-,brake-,shift-,and throttle-by-wire systems.It is not only the key technology for new energy vehicles but also an important support for promoting their sustainable development.This article presents an in-depth study on X-by-wire chassis technology in new energy vehicles and its basic working principle.

Fusion: It’s Time to Color outside the Lines

There has been some good news, and some bad news in the controlled fusion community recently. The good news is that the Lawrence Livermore National Laboratory (LLNL) has recently produced a burning plasma. It succeeded on several of its shots where ~1.5 - 2 megajoules from its laser (National Ignition Facility, or NIF) has generated ~1.3 - 3 megajoules of fusion products. The highest ratio of fusion energy to laser energy it achieved, defined as its Q, was 1.5 at the time of this writing. While LLNL is sponsored by nuclear stockpile stewardship, this author sees a likely path from their result to fusion for energy for the world, a path using a very different laser and a very different target configuration. The bad news is that the International Tokamak Experimental Reactor (ITER) has continued to stumble on more and more delays and cost overruns, as its capital cost has mushroomed from ~$5 billion to ~ $25 B. This paper argues that the American fusion effort, for energy for the civilian economy, should switch its emphasis not only from magnetic fusion to inertial fusion but should also take much more seriously fusion breeding. Over the next few decades, the world might well be setting up more and more thermal nuclear reactors, and these might need fuel which only fusion breeders can supply. In other words, fusion should begin to color outside the lines.

Driving Range Parametric Analysis of Electric Vehicles Driven by Interior Permanent Magnet Motors Considering Driving Cycles

This paper presents parametric analysis of driving range of electric vehicles driven by V-type interior permanent magnet motors aiming at maximum driving range,i.e.,minimal total energy consumption of the motors over a driving cycle.Influence of design parameters including tooth width,slot depth,split ratio(the ratio of inner diameter to outer diameter of the stator),and V-type magnet angle on the energy consumption of the motors and driving range of electric vehicles over a driving cycle is investigated in detail.The investigation is carried out for two typical driving cycles with different characteristics to represent different conditions:One is high-speed,low-torque cycle-Highway Fuel Economy Test and the other is low-speed,high-torque cycle-Artemis Urban Driving Cycle.It shows that for both driving cycles,the same parameters may have different influence on the energy consumption of the motors,as well as driving range of electric vehicles.

RGS12 represses oral squamous cell carcinoma by driving M1 polarization of tumor-associated macrophages via controlling ciliary MYCBP2/KIF2A signaling

Tumor-associated macrophages(TAMs)play crucial roles in tumor progression and immune responses.However,mechanisms of driving TAMs to antitumor function remain unknown.Here,transcriptome profiling analysis of human oral cancer tissues indicated that regulator of G protein signaling 12(RGS12)regulates pathologic processes and immune-related pathways.Mice with RGS12knockout in macrophages displayed decreased M1 TAMs in oral cancer tissues,and extensive proliferation and invasion of oral cancer cells.RGS12 increased the M1 macrophages with features of increased ciliated cell number and cilia length.Mechanistically,RGS12 associates with and activates MYC binding protein 2(MYCBP2)to degrade the cilia protein kinesin family member 2A(KIF2A)in TAMs.Our results demonstrate that RGS12 is an essential oral cancer biomarker and regulator for immunosuppressive TAMs activation.

Evolutionary Decision-Making and Planning for Autonomous Driving Based on Safe and Rational Exploration and Exploitation

Decision-making and motion planning are extremely important in autonomous driving to ensure safe driving in a real-world environment.This study proposes an online evolutionary decision-making and motion planning framework for autonomous driving based on a hybrid data-and model-driven method.First,a data-driven decision-making module based on deep reinforcement learning(DRL)is developed to pursue a rational driving performance as much as possible.Then,model predictive control(MPC)is employed to execute both longitudinal and lateral motion planning tasks.Multiple constraints are defined according to the vehicle’s physical limit to meet the driving task requirements.Finally,two principles of safety and rationality for the self-evolution of autonomous driving are proposed.A motion envelope is established and embedded into a rational exploration and exploitation scheme,which filters out unreasonable experiences by masking unsafe actions so as to collect high-quality training data for the DRL agent.Experiments with a high-fidelity vehicle model and MATLAB/Simulink co-simulation environment are conducted,and the results show that the proposed online-evolution framework is able to generate safer,more rational,and more efficient driving action in a real-world environment.

Surrounding rock control of gob-side entry driving with narrow coal pillar and roadway side sealing technology in Yangliu Coal Mine

Gob-side entry driving can increase coal recovery ratio, and it is implied in many coal mines. Based on geological condition of 10416 working face tailentry in Yangliu Coal Mine, the surrounding rock deformation characteristics of gob-side entry driving with narrow coal pillar is analysed, reasonable size of coal pillar and reasonable roadway excavation time after mining are achieved. Surrounding rock control technology and effective roadway side sealing technology are proposed and are taken into field practice. The results showed that a safer and more efficient mining of working face can be achieved. In addition, results of this paper also have important theoretical significance and valuable reference for surrounding rock control technology of gob-side entry driving with narrow coal pillar under special geological condition.

Cable-truss supporting system for gob-side entry driving in deep mine and its application

In order to solve the large deformation controlling problem for surrounding rock of gob-side entry driving under common cable anchor support in deep mine, site survey, physical modeling experiment, numerical simulation and field measurement were synthetically used to analyze the deformation and failure characteristics of surrounding rock. Besides, applicability analysis, prestress field distribution characteristics of surrounding rock and the control effect on large deformation of surrounding rock were also further studied for the gob-side entry driving in deep mine using the cable-truss supporting system. The results show that, first, compared with no support and traditional bolt anchor support, roof cable-truss system can effectively restrain the initiation and propagation of tensile cracks in the roof surrounding rock and arc shear cracks in the two sides, moreover, the broken development of surrounding rock, roof separation and extrusion deformation between the two sides of the roadway are all controlled; second, a prestressed belt of trapezoidal shape is generated in the surrounding rock by the cable-truss supporting system, and the prestress field range is wide. Especially, the prestress concentration belt in the shallow surrounding rock can greatly improve the anchoring strength and deformation resisting capability of the rock stratum;third, an optimized support system of ‘‘roof and side anchor net beam, roof cable-truss supporting system and anchor cable of the narrow coal pillar" was put forward, and the support optimization design and field industrial test were conducted for the gob-side entry driving of the working face 5302 in Tangkou Mine, from which a good supporting effect was obtained.

Prediction of ground-borne vibration induced by impact pile driving:numerical approach and experimental validation

Deep foundations are currently used in engineering practice to solve problems caused by weak geotechnical characteristics of the ground.Impact pile driving is an interesting and viable solution from economic and technical points of view.However,it is necessary to ensure that the environmental drawbacks,namely ground-borne vibration,are adequately met.For this purpose,the authors propose an axisymmetric finite element method-perfectly matched layer(FEM-PML)approach,where the nonlinear behavior of the soil is addressed through an equivalent linear methodology.Given the complexity of the problem,an experimental test site was developed and fully characterized.The experimental work comprised in-situ and laboratory soil characterization,as well as the measurement of vibrations induced during pile driving.The comparison between experimental and numerical results demonstrated a very good agreement,from which it can be concluded that the proposed numerical approach is suitable for the prediction of vibrations induced by impact pile driving.The experimental database is available as supplemental data and may be used by other researchers in the validation of their prediction models.

Ground-borne vibrations induced by impact pile driving: experimental assessment and mitigation measures

Impact pile driving is an interesting technique for the construction of deep foundations from a practical and economical point of view.However,the generalization of this technique can be restricted due to the excessive vibration levels that can be generated,which can be especially problematic in residential areas.However,different mitigation measures can be applied to prevent excessive vibration levels inside buildings located near construction sites.To compare its efficiency through a numerical prediction tool,two experimental test sites are first presented and characterized.From the results obtained,it was found that the construction of an open trench near the impact source can be used as an efficient mitigation measure to reduce the maximum vibration levels evaluated in this study.

Failure laws of narrow pillar and asymmetric control technique of gob-side entry driving in island coal face

In allusion to the problems of complex stress distribution in the surrounding rock and deformation failure laws, as well as the difficulty in roadway supporting of the gob-side entry driving in the island coal face, 2107 face in Chengjiao Colliery is researched as an engineering case. Through physical mechanical test of rock, theoretical and numerical simulation analyses of rock, the analysis model of the roadway overlying strata structure was established, and its parameters quantified. To reveal the deformation law of the surrounding rock, the stability of the overlying strata structure was studied before, during and after the roadway driving. According to the field conditions, the stress distribution in coal pillar was quantified, and the surrounding rock deformation feature studied with different widths of the pillars in gob-side entry driving. Finally, the pillar width of 4 m was considered as the most reasonable. The research results show that there is great difference in support conditions among roadway roof, entity coal side and narrow pillar side. Besides, the asymmetric control technique for support of the surrounding rock was proposed. The asymmetric control technique was proved to be reasonable by field monitoring, support by bolt-net, steel ladder and steel wire truss used in narrow pillar side.

Driving pressure in mechanical ventilation:A review

Driving pressure(ΔP)is a core therapeutic component of mechanical ventilation(MV).Varying levels ofΔP have been employed during MV depending on the type of underlying pathology and severity of injury.However,ΔP levels have also been shown to closely impact hard endpoints such as mortality.Considering this,conducting an in-depth review ofΔP as a unique,outcome-impacting therapeutic modality is extremely important.There is a need to understand the subtleties involved in making sureΔP levels are optimized to enhance outcomes and minimize harm.We performed this narrative review to further explore the various uses ofΔP,the different parameters that can affect its use,and how outcomes vary in different patient populations at different pressure levels.To better utilizeΔP in MV-requiring patients,additional large-scale clinical studies are needed.

Stability of coal pillar in gob-side entry driving under unstable overlying strata and its coupling support control technique

Considering the situation that it is difficult to control the stability of narrow coal pillar in gob-side entry driving under unstable overlying strata, the finite difference numerical simulation method was adopted to analyze the inner stress distribution and its evolution regularity, as well as the deformation characteristics of narrow coal pillar in gob-side entry driving, in the whole process from entry driving of last working face to the present working face mining. A new method of narrow coal pillar control based on the triune coupling support technique (TCST), which includes that high-strength prestressed thread steel bolt is used to strain the coal on the goaf side, and that short bolt to control the integrity of global displacement zone in coal pillar on the entry side, and that long grouting cable to fix anchor point to constrain the bed separation between global displacement zone and fixed zone, is thereby generated and applied to the field production. The result indicates that after entry excavating along the gob under unstable overlying strata, the supporting structure left on the gob side of narrow coal pillar is basically invalid to maintain the coal-pillar stability, and the large deformation of the pillar on the gob side is evident. Except for the significant dynamic pressure appearing in the coal mining of last working face and overlying strata stabilizing process, the stress variation inside the coal pillar in other stages are rather steady, however, the stress expansion is obvious and the coal pillar continues to deform. Once the gob-side entry driving is completed, a global displacement zone on the entry side appears in the shallow part of the pillar, whereas, a relatively steady fixed zone staying almost still in gob-side entry driving and present working face mining is found in the deep part of the pillar. The application of TCST can not only avoid the failure of pillar supporting structure, but exert the supporting capacity of the bolting structure left in the pillar of last sublevel entry, thus to jointly maintain the stability of coal pillar.

Stress and deformation analysis of gob-side pre-backfill driving procedure of longwall mining:a case study

At present,non-pillar entry protection in longwall mining is mainly achieved through either the gob-side entry retaining(GER)procedure or the gob-side entry driving(GED)procedure.The GER procedure leads to difficulties in maintaining the roadway in mining both the previous and current panels.A narrow coal pillar about 5-7 m must be left in the GED procedure;therefore,it causes permanent loss of some coal.The gob-side pre-backfill driving(GPD)procedure effectively removes the wasting of coal resources that exists in the GED procedure and finds an alternative way to handle the roadway maintenance problem that exists in the GER procedure.The FLAC^(3D) software was used to numerically investigate the stress and deformation distributions and failure of the rock mass surrounding the previous and current panel roadways during each stage of the GPD procedure which requires"twice excavation and mining".The results show that the stress distribution is slightly asymmetric around the previous panel roadway after the"primary excavation".The stronger and stiffer backfill compared to the coal turned out to be the main bearing body of the previous panel roadway during the"primary mining".The highest vertical stresses of 32.6 and 23.1 MPa,compared to the in-situ stress of 10.5 MPa,appeared in the backfill wall and coal seam,respectively.After the"primary mining",the peak vertical stress under the coal seam at the floor level was slightly higher(18.1 MPa)than that under the backfill(17.8 MPa).After the"secondary excavation",the peak vertical stress under the coal seam at the floor level was slightly lower(18.7 MPa)than that under the backfill(19.8 MPa);the maximum floor heave and maximum roof sag of the current panel roadway were 252.9 and 322.1 mm,respectively.During the"secondary mining",the stress distribution in the rock mass surrounding the current panel roadway was mainly affected by the superposition of the front abutment pressure from the current panel and the side abutment pressure from the previous panel.The floor heave of the current panel roadway reached a maximum of 321.8 mm at 5 m ahead of the working face;the roof sag increased to 828.4 mm at the working face.The peak abutment pressure appeared alternately in the backfill and the coal seam during the whole procedure of"twice excavation and mining"of the GPD procedure.The backfill provided strong bearing capacity during all stages of the GPD procedure and exhibited reliable support for the roadway.The results provide scientific insight for engineering practice of the GPD procedure.

Spatiotemporal patterns and driving factors of soil protection in the wind-water erosion area of Chinese Loess Plateau

As one of typical areas in the world,northern Chinese Loess Plateau experiences serious wind-water erosion,which leads to widespread land degradation.During the past decades,an ecological engineering was implemented to reduce soil erosion and improve soil protection in this area.Thus,it is necessary to recognize the basic characteristics of soil protection for sustainable prevention and wind-water erosion control in the later stage.In this study,national wind erosion survey model and revised universal soil loss equation were used to analyze the spatiotemporal evolution and driving forces of soil protection in the wind-water erosion area of Chinese Loess Plateau during 2000–2020.Results revealed that:(1)during 2000–2020,total amount of soil protection reached up to 15.47×10^(8) t,which was realized mainly through water and soil conservation,accounting for 63.20%of the total;(2)soil protection was improved,with increases in both soil protection amount and soil retention rate.The amounts of wind erosion reduction showed a decrease trend,whereas the retention rate of wind erosion reduction showed an increase trend.Both water erosion reduction amount and retention rate showed increasing trends;and(3)the combined effects of climate change and human activities were responsible for the improvement of soil protection in the wind-water erosion area of Chinese Loess Plateau.The findings revealed the spatiotemporal patterns and driving forces of soil protection,and proposed strategies for future soil protection planning in Chinese Loess Plateau,which might provide valuable references for soil erosion control in other wind-water erosion areas of the world.

Deployment Dynamic Modeling and Driving Schemes for a Ring-Truss Deployable Antenna

Mesh reflector antennas are widely used in space tasks owing to their light weight,high surface accuracy,and large folding ratio.They are stowed during launch and then fully deployed in orbit to form a mesh reflector that transmits signals.Smooth deployment is essential for duty services;therefore,accurate and efficient dynamic modeling and analysis of the deployment process are essential.One major challenge is depicting time-varying resistance of the cable network and capturing the cable-truss coupling behavior during the deployment process.This paper proposes a general dynamic analysis methodology for cable-truss coupling.Considering the topological diversity and geometric nonlinearity,the cable network's equilibrium equation is derived,and an explicit expression of the time-varying tension of the boundary cables,which provides the main resistance in truss deployment,is obtained.The deployment dynamic model is established,which considers the coupling effect between the soft cables and deployable truss.The effects of the antenna's driving modes and parameters on the dynamic deployment performance were investigated.A scaled prototype was manufactured,and the deployment experiment was conducted to verify the accuracy of the proposed modeling method.The proposed methodology is suitable for general cable antennas with arbitrary topologies and parameters,providing theoretical guidance for the dynamic performance evaluation of antenna driving schemes.

Land use change and its driving factors in the ecological function area:A case study in the Hedong Region of the Gansu Province,China

Land use and cover change(LUCC)is important for the provision of ecosystem services.An increasing number of recent studies link LUCC processes to ecosystem services and human well-being at different scales recently.However,the dynamic of land use and its drivers receive insufficient attention within ecological function areas,particularly in quantifying the dynamic roles of climate change and human activities on land use based on a long time series.This study utilizes geospatial analysis and geographical detectors to examine the temporal dynamics of land use patterns and their underlying drivers in the Hedong Region of the Gansu Province from 1990 to 2020.Results indicated that grassland,cropland,and forestland collectively accounted for approximately 99% of the total land area.Cropland initially increased and then decreased after 2000,while grassland decreased with fluctuations.In contrast,forestland and construction land were continuously expanded,with net growth areas of 6235.2 and 455.9 km^(2),respectively.From 1990 to 2020,cropland was converted to grassland,and both of them were converted to forestland as a whole.The expansion of construction land primarily originated from cropland.From 2000 to 2005,land use experienced intensified temporal dynamics and a shift of relatively active zones from the central to the southeastern region.Grain yield,economic factors,and precipitation were the major factors accounting for most land use changes.Climatic impacts on land use changes were stronger before 1995,succeeded by the impact of animal husbandry during 1995-2000,followed by the impacts of grain production and gross domestic product(GDP)after 2000.Moreover,agricultural and pastoral activities,coupled with climate change,exhibited stronger enhancement effects after 2000 through their interaction with population and economic factors.These patterns closely correlated with ecological restoration projects in China since 1999.This study implies the importance of synergy between human activity and climate change for optimizing land use via ecological patterns in the ecological function area.

Landscape ecological risk assessment and its driving factors in the Weihe River basin,China

Weihe River basin is of great significance to analyze the changes of land use pattern and landscape ecological risk and to improve the ecological basis of regional development.Based on land use data of the Weihe River basin in 2000,2010,and 2020,with the support of Aeronautical Reconnaissance Coverage Geographic Information System(ArcGIS),GeoDa,and other technologies,this study analyzed the spatial-temporal characteristics and driving factors of land use pattern and landscape ecological risk.Results showed that land use structure of the Weihe River basin has changed significantly,with the decrease of cropland and the increase of forest land and construction land.In the past 20 a,cropland has decreased by 7347.70 km2,and cropland was mainly converted into forest land,grassland,and construction land.The fragmentation and dispersion of ecological landscape pattern in the Weihe River basin were improved,and land use pattern became more concentrated.Meanwhile,landscape ecological risk of the Weihe River basin has been improved.Severe landscape ecological risk area decreased by 19,177.87 km2,high landscape ecological risk area decreased by 3904.35 km2,and moderate and low landscape ecological risk areas continued to increase.It is worth noting that landscape ecological risks in the upper reaches of the Weihe River basin are still relatively serious,especially in the contiguous areas of high ecological risk,such as Tianshui,Pingliang,Dingxi areas and some areas of Ningxia Hui Autonomous Region.Landscape ecological risk showed obvious spatial dependence,and high ecological risk area was concentrated.Among the driving factors,population density,precipitation,normalized difference vegetation index(NDVI),and their interactions are the most important factors affecting the landscape ecological risk of the Weihe River basin.The findings significantly contribute to our understanding of the ecological dynamics in the Weihe River basin,providing crucial insights for sustainable management in the region.