Responses of vegetation yield to precipitation and reference evapotranspiration in a desert steppe in Inner Mongolia,China

Drought,which restricts the sustainable development of agriculture,ecological health,and social economy,is affected by a variety of factors.It is widely accepted that a single variable cannot fully reflect the characteristics of drought events.Studying precipitation,reference evapotranspiration(ET_(0)),and vegetation yield can derive information to help conserve water resources in grassland ecosystems in arid and semi-arid regions.In this study,the interactions of precipitation,ET_(0),and vegetation yield in Darhan Muminggan Joint Banner(DMJB),a desert steppe in Inner Mongolia Autonomous Region,China were explored using two-dimensional(2D)and three-dimensional(3D)joint distribution models.Three types of Copula functions were applied to quantitatively analyze the joint distribution probability of different combinations of precipitation,ET_(0),and vegetation yield.For the precipitation–ET_(0)dry–wet type,the 2D joint distribution probability with precipitation≤245.69 mm/a or ET_(0)≥959.20 mm/a in DMJB was approximately 0.60,while the joint distribution probability with precipitation≤245.69 mm/a and ET_(0)≥959.20 mm/a was approximately 0.20.Correspondingly,the joint return period that at least one of the two events(precipitation was dry or ET_(0)was wet)occurred was 2 a,and the co-occurrence return period that both events(precipitation was dry and ET_(0)was wet)occurred was 5 a.Under this condition,the interval between dry and wet events would be short,the water supply and demand were unbalanced,and the water demand of vegetation would not be met.In addition,when precipitation remained stable and ET_(0)increased,the 3D joint distribution probability that vegetation yield would decrease due to water shortage in the precipitation–ET_(0)dry–wet years could reach up to 0.60–0.70.In future work,irrigation activities and water allocation criteria need to be implemented to increase vegetation yield and the safety of water resources in the desert steppe of Inner Mongolia.

Ecological-Based Mining:A Coal-Water-Thermal Collaborative Paradigm in Ecologically Fragile Areas in Western China

A substantial reduction in groundwater level,exacerbated by coal mining activities,is intensifying water scarcity in western China’s ecologically fragile coal mining areas.China’s national strategic goal of achieving a carbon peak and carbon neutrality has made eco-friendly mining that prioritizes the protection and efficient use of water resources essential.Based on the resource characteristics of mine water and heat hazards,an intensive coal-water-thermal collaborative co-mining paradigm for the duration of the mining process is proposed.An integrated system for the production,supply,and storage of mining companion resources is achieved through technologies such as roof water inrush prevention and control,hydrothermal quality improvement,and deep-injection geological storage.An active preventive and control system achieved by adjusting the mining technology and a passive system centered on multiobjective drainage and grouting treatment are suggested,in accordance with the original geological characteristics and dynamic process of water inrush.By implementing advanced multi-objective drainage,specifically designed to address the“skylight-type”water inrush mode in the Yulin mining area of Shaanxi Province,a substantial reduction of 50%in water drillings and inflow was achieved,leading to stabilized water conditions that effectively ensure subsequent safe coal mining.An integrated-energy complementary model that incorporates the clean production concept of heat utilization is also proposed.The findings indicate a potential saving of 8419 t of standard coal by using water and air heat as an alternative heating source for the Xiaojihan coalmine,resulting in an impressive energy conservation of 50.2%and a notable 24.2%reduction in carbon emissions.The ultra-deep sustained water injection of 100 m^(3)·h^(-1)in a single well would not rupture the formation or cause water leakage,and 7.87×10^(5)t of mine water could be effectively stored in the Liujiagou Formation,presenting a viable method for mine-water management in the Ordos Basin and providing insights for green and low-carbon mining.

Triaxial mechanical properties and precursors of instability damage in rocks with different laminar dip angles

To investigate the mechanical failure characteristics of volcanic breccia with different bedding dip angles in deep layers,triaxial compression experiments were conducted on specimens taken from volcanic rock layers in the Junggar Basin,Xinjiang.By changing the confining pressure,we compared the mechanical properties,acoustic emission characteristics,and fractal features of the acoustic emission sequence for volcanic breccia with different bedding dip angles.The research results indicate that as the bedding dip angle increases,peak strength,internal friction angle,and cohesion exhibit a“U-shaped”variation pattern.The correlation dimension of the acoustic emission amplitude was calculated using the G-P algorithm,revealing that volcanic breccia exhibits fractal characteristics.Furthermore,a positive correlation between the correlation dimension and the bedding dip angle was observed.When the stress of the test specimen reaches 0.8σ_(c),there is a significant decrease in the fractal dimension,serving as a criterion for predicting the failure of the specimen.By analyzing the changes in fractal dimension at different stress levels,the slope of the fractal dimension△D<-0.5 can be used as a precursor to failure for test specimens with a bedding dip angle of 15°≤β≤45°.Similarly,when the bedding dip angle of the specimen is 0°≤β<15°or 45°<β≤90°,△D<0 can be considered as a precursor to specimen failure.This study provides theoretical references for understanding the failure patterns of volcanic rock.

Mechanical properties and energy evolution law of water bearing sandstone under cyclic

Due to excavation disturbances and the coupled hydro-mechanical effects,deep rock masses experience nonlinear large deformations in the surrounding rock,necessitating an urgent exploration of the rock damage and failure mechanisms from the perspectives of hydro-mechanical coupling and mechanical properties.Therefore,this study conducted uniaxial cyclic loading-unloading tests on sandstone samples with different water contents(0%,0.26%,0.52%,0.78%,and 1.04%)to investigate the microstructural evolution,energy evolution laws,and failure characteristics under varying water contents and cyclic loading conditions.The main conclusions are as follows:(1)Concerning micro-pore structures,as the water content increases,the porosity and maximum pore size of the sandstone first decrease and then increase.At 0%water content,the porosity is 4.82%and the maximum pore size is 31.94μm.At 0.26%water content,both porosity and maximum pore size decrease to 3.03%and 16.15μm,respectively.When the water content reaches 1.04%,the porosity and maximum pore size increase to 14.34%and 45.99μm,respectively.(2)Regarding energy evolution laws,the energy evolution of the specimens during cyclic loading-unloading mainly converts to elastic energy,showing a step-wise increase in energy.Further analysis reveals that the water content has a significant impact on the dissipation energy coefficient of the sandstone.At lower stress levels(<0.4σmax),the water content has a negligible effect,while at higher stress levels(>0.85σmax),an increase in water content leads to increased fluctuations in the dissipation energy coefficient.(3)In terms of failure characteristics,with increasing water content,the failure mode of the specimens shifts from primary crack failure to microcrack failure,corresponding to the energy evolution during cyclic loading-unloading processes.

Effects of Temperature and Liquid Nitrogen(LN2)on Coal’s Mechanical and Acoustic Emission(AE)Properties

Liquid nitrogen has shown excellent performances as a good fracturing medium in the extraction of unconventional natural gas,and its application in coalbed methane extraction is currently a research hotspot.This study focuses on the acoustic emission properties of coal specimens treated utilizing liquid nitrogen with varying initial temperatures in a three-point bending environment.Through examination of the load-displacement curves of the considered coal samples,their mechanical properties are also revealed for different initial temperatures and cycling frequencies.The findings demonstrate a gradual decline in the maximum load capacity of coal rock as the temperature rises.Similarly,when subjected to the same temperature,an escalation in the cycling frequency leads to a reduction in the peak load of coal rock.This suggests that both temperature and cycling frequency exert a notable impact on the fracturing efficacy of liquid nitrogen.Freeze-thaw cycling treatments and exposure to high-temperature conditions can activate preexisting damage in the coal rock,and,accordingly,influence its mechanical properties.In particular,throughout the progressive loading of coal rock samples,the failure mechanisms are predominantly characterized by the occurrence of tensile cracks,succeeded by the development,spread,and fracture of shear fissures.

A depressant for marmatite flotation:Synthesis,characterisation and floatation performance

This study synthesised a zincic salt(ZS)as a depressant for marmatite-galena separation.The effect of ZS on the flotation of marmatite and galena was investigated through micro-flotation tests.88.89%of the galena was recovered and 83.39%of the marmatite was depressed with ZS dosage of 750 mg·L^(−1)at pH=4.The depression mechanism of ZS on marmatite was investigated by a variety of techniques,including adsorption measurements,Fourier transform infrared(FTIR),X-ray photoelectron spectroscopic(XPS)analysis,and time of flight secondary ion mass spectrometry(ToF-SIMS).Results of adsorption tests and FTIR reveal that ZS adsorbed on marmatite surface and impeded the subsequent adsorption of butyl xanthate(BX).The results of XPS and ToF-SIMS indicate that the ZnO_(2)^(3-)released by ZS could be chemisorbed on the marmatite surface and depress marmatite flotation.

Adsorption characteristics of Pb(Ⅱ)ions on sulfidized hemimorphite surface under ammonium sulfate system

In this work,the effect of ammonium sulfate on the adsorption characteristics of low-concentration Pb(Ⅱ)ions on the sulfidized hemimorphite surface was comprehensively investigated.The results showed that ammonium sulfate could increase the maximum recovery of hemimorphite from 69.42%to 88.24%under a low concentration of Pb(Ⅱ)ions.On the hemimorphite surface pretreated with ammonium sulfate,the adsorption of Pb(Ⅱ)ions was enhanced and the main species of Pb adsorbed was changed from Pb―O/OH to PbS.This was due to the larger amount of ZnS providing more effective adsorption sites for Pb components to generate Pb S.Meanwhile,the intensity of ZnS decreased with the formation of PbS,demonstrating that ZnS was covered by PbS which formed later on the mineral surface.It was beneficial for the adsorption of butyl xanthate on the hemimorphite surface to form more hydrophobic substances.As a result,ammonium sulfate played a crucial role in realizing the efficient recovery of hemimorphite.

Strategies for Improving the Effectiveness of Professional Practice for Full-Time Professional Master Degree Postgraduate in Mineral Processing Engineering

In order to gain practical experience and hands-on skills,full-time professional master degree postgraduate in mineral processing engineering should engage in professional practices.Nonetheless,a series of problems,including insufficient time for practice,low management level,inadequate implementation of the double-supervisor system,and poor results of professional practice,has reduced the effectiveness of professional practice.In view of the aforementioned problems and the characteristics of the discipline,this paper proposes several strategies for improving the effectiveness of professional practice for postgraduates in mineral processing engineering.

Effect of ammonium sulfate on the formation of zinc sulfide species on hemimorphite surface and its role in sulfidation flotation

Effectively strengthening the surface sulfidation is essential for recovering hemimorphite by froth flotation.In this work,inductively coupled plasma optical emission spectrometer(ICP-OES)measurements,Visual MINTEQ calculation,X-ray photoelectron spectroscopy(XPS)analysis,time of flight secondary ion mass spectrometry(ToF-SIMS)analysis,and micro-flotation experiments were explored to systematically investigate the effect of ammonium sulfate((NH_(4))_(2)SO_(4))on the formation of zinc sulfide species on hemimorphite surface and its role in sulfidation flotation.The results showed that(NH_(4))_(2)SO_(4)exhibited a positive influence on hemimorphite sulfidation flotation.It was ascribed to the number of zinc components in the form of Zn^(2+)and[Zn(NH_(3))_(i)]^(2+)(i=1–4)increased in the flotation system after hemimorphite treatment with(NH_(4))_(2)SO_(4),which was beneficial to its interaction with sulfur species in solution,resulting in a dense and stable zinc sulfide layer generated on the hemimorphite surface.[Zn(NH_(3))_(i)]^(2+)participated in the sulfidation reaction of hemimorphite as a transition state.In addition the sulfidation reaction of hemimorphite was accelerated by(NH_(4))_(2)SO_(4).Thus,(NH_(4))_(2)SO_(4)presents a vital role in promoting the sulfidation of hemimorphite.

Effect of rain enrichment on soil respiration of Nitraria sphaerocarpa community in a hyperarid area

In order to analyze the effect of rain enrichment on soil respiration rate of a Nitraria sphaerocarpa community, we measured soil respiration rate in bare and vegetated areas in a hyperarid area （Dunhuang） during the growing season. Results show that rain enrichment can increase bare and vegetated soil respiration rates. The more rainfall enrichment, the greater the increment and the longer duration time effect for soil respiration rate. 200% （16 mm） and 300% （24 mm） of rain enrichment can significantly increase bare soil respiration rates by 90% and 106% （P〈0.01）, respectively. By contrast, areas with 100% （8 mm）, 200% （16 mm） and 300% （24 mm） of rain enrichment can significantly increase shrub area respiration rates by 68%, 157% and 205% （P〈0.01）, respectively. The response time of bare and vegetated soil respiration to rainfall enrichment is asynchronous. Response variable of soil respiration in vegetated soil is higher （118%） than in bare soil. There was significant positive correlation between soil respiration rate and soil water content during the growing season （P〈0.01）. For every 1 mm increment of precipitation, soil respiration rate increased by 0.01 and 0.04 pmol/（m2.s）, respectively in vegetated and bare soils.

A Novel Aquila Optimizer Based PV Array Reconfiguration Scheme to Generate Maximum Energy under Partial Shading Condition

This paper develops a real-time PV arrays maximum power harvesting scheme under partial shading condition(PSC)by reconfiguring PV arrays using Aquila optimizer(AO).AO is based on the natural behaviors of Aquila in capturing prey,which can choose the best hunting mechanism ingeniously and quickly by balancing the local exploitation and global exploration via four hunting methods of Aquila:choosing the searching area through high soar with the vertical stoop,exploring in different searching spaces through contour flight with quick glide attack,exploiting in convergence searching space through low flight with slow attack,and swooping through walk and grabbing prey.In general,PV arrays reconfiguration is a problem of discrete optimization,thus a series of discrete operations are adopted in AO to enhance its optimization performance.Simulation results based on 10 cases under PSCs show that the mismatched power loss obtained by AO is the smallest compared with genetic algorithm,particle swarm optimization,ant colony algorithm,grasshopper optimization algorithm,and butterfly optimization algorithm,which reduced by 4.34%against butterfly optimization algorithm.

Metabolic Characterization of the Badagan Constitution in Mongolian Medicine by Ultrahigh-Performance Liquid Chromatography/Quadrupole Time-of-Flight Mass Spectrometry/MS

This study aimed to identify the potential metabolic biomarkers of the Badagan constitution(BC) in Mongolian medicine. Serum samples from the participants with BCs(n = 32) and aggregative constitutions(n = 30) were analyzed by using ultrahigh-performance liquid chromatography/mass spectrometry. Meanwhile, principal component analysis and orthogonal partial least squares discriminant analysis were used to characterize the endogenous metabolites and potential biomarkers, respectively. Fifteen of the 18 biomarkers in six metabolic pathways were significantly upregulated,including phosphatidylserine, sphingolipids, tryptophan, riboflavin and glutathione, and three biomarkers were significantly downregulated,including lysophosphatidylcholine(LysoPC)(18:1), LysoPC(16:1), and lysophosphatidylethanolamine(LysoPE)(22:2). This study also implied that sphingolipid metabolism, glycerophospholipid metabolism, and tryptophan metabolism played important roles in the BC. Therefore, metabolomics may improve the diagnostic efficacy of the BC in terms of the accuracy and comprehensiveness of a diagnosis based on this constitution. This result further reveals the mechanism of the constitution type in Mongolian medicine and provides a reference for the treatment of related diseases.

Low-Carbon Routing Based on Improved Artificial Bee Colony Algorithm for Electric Trackless Rubber-Tyred Vehicles

Trackless rubber-tyerd vehicles are the core equipment for auxiliary transportation in inclined-shaft coal mines,and the rationality of their routes plays the direct impact on operation safety and energy consumption.Rich studies have been done on scheduling rubber-tyerd vehicles driven by diesel oil,however,less works are for electric trackless rubber-tyred vehicles.Furthermore,energy consumption of vehicles gives no consideration on the impact of complex roadway and traffic rules on driving,especially the limited cruising ability of electric trackless rubber-tyred vehichles(TRVs).To address this issue,an energy consumption model of an electric trackless rubber-tyred vehicle is formulated,in which the effects from total mass,speed profiles,slope of roadways,and energy management mode are all considered.Following that,a low-carbon routing model of electric trackless rubber-tyred vehicles is built to minimize the total energy consumption under the constraint of vehicle avoidance,allowable load,and endurance power.As a problem-solver,an improved artificial bee colony algorithm is put forward.More especially,an adaptive neighborhood search is designed to guide employed bees to select appropriate operator in a specific space.In order to assign onlookers to some promising food sources reasonably,their selection probability is adaptively adjusted.For a stagnant food source,a knowledge-driven initialization is developed to generate a feasible substitute.The experimental results on four real-world instances indicate that improved artificial bee colony algorithm(IABC)outperforms other comparative algorithms and the special designs in its three phases effectively avoid premature convergence and speed up convergence.

Evaluating the applicability of the water erosion prediction project(WEPP)model to runoff and soil loss of sandstone reliefs in the Loess Plateau,China

Soil erosion is one of the most serious environmental issues,especially in vulnerable areas such as the Pisha sandstone regions located in the Loess Plateau(China).In these types of reliefs,long-term studies monitoring runoff and soil loss are scarce,and even more considering the efficiency of different soil management techniques applied to reduce land degradation.In this study,seven years(2014-2020)of in-situ measurements of surface runoff and soil loss for different land uses(forestland,shrubland,grassland,farmland,and bare land)in a Pisha Sandstone environment at the Loess Plateau were con-ducted.We applied the Water Erosion Prediction Project(WEPP)model combining the large database with the precipitation regimes.Our results showed that runoff volume coming from observed and simulated data exhibited significant differences among them depending on the different vegetation types.Runoff and soil loss were different among diverse land use types as follows:farmland>grassland>shrubland>forestland.After conducting a calibration,we found satisfactorily simulated surface runoff and sediment yield based on precipitation regimes and land uses at sandstone reliefs.Simulation performance of surface runoff was better than sediment yield.The range of standard error of the model simulation for event and annual values of runoff were 4.71 mm and 12.19 mm,respectively.The standard error for event and annual values of soil loss were 4.19 t/hm^(2)and 21.86 t/hm^(2).In the calibration group,R2 of runoff and soil loss were 0.92 and 0.86 respectively,while Nash-Sutcliffe coefficient(E)reached 0.90 and 0.85,respectively.In the validation group,the R2 for both runoff and soil loss were 0.82 and 0.56,respectively.Nash-Sutcliffe coefficient(E)were 0.77 and 0.54 for the runoff and sediment yield.We concluded that using a detailed monitoring dataset,the WEPP model could accu-rately simulate and predict water erosion in the hillslopes of Pisha sandstone area.

Peak-Shaving of the Oxy-Fuel Power Plant Coupled with Liquid O_(2)Storage

Integrating a high proportion of intermittent renewable energy provides a solution for the higher peak-shaving capacity of coal-fired power plants.Oxy-fuel combustion is one of the most promising carbon reduction technologies for coal-fired power plants.This study has proposed a novel oxy-fuel power plant that is coupled with both liquid O_(2)storage and cold energy recovery systems in order to adapt to the peak-shaving requirements.The liquid O_(2)storage system uses cheap valley electricity to produce liquid O_(2)for a later use in the peak period to enhance the peak-shaving capacity.Meanwhile,the cold energy recovery system has been introduced to recover the physical latent energy during the phase change of liquid O_(2)to increase the power generation in the peak period.Technical economies of three power plants,i.e.a 330 MW(e)oxy-fuel power plant as reference(Case 1),the same power plant coupled with only liquid O_(2)storage system(Case 2),and the same power plant coupled with both liquid O_(2)storage and cold energy recovery systems(Case 3),have been analyzed and compared.Thermodynamic performance analysis indicates that the peaking capacity of Case 3 can reach the range of 106.03 to 294.22 MW(e),and the maximum peak-shaving coefficient can be as high as 2.77.Exergy analysis demonstrates that the gross exergy efficiency of Cases 2 and 3 reaches 32.18%and 33.57%,respectively,in the peak period,which are significantly higher than that of 26.70%in Case 1.Economic analysis shows that through selling the liquid O_(2)and liquid CO_(2),combined with carbon trading,the levelized cost of electricity(LCOE)of the three cases have been greatly reduced,with the lowest one of 30.90 USD/MWh shown in Case 3.For a comprehensive consideration,Case 3 can be considered a future reference of oxy-fuel power plant with the best thermodynamic and economic performance.

Stability Control Method for Hybrid AC-DC Transmission Systems Considering Cross-region Multi-energy Coordination

China has built the largest hybrid AC-DC power systems with the highest voltage levels in the world.How to effectively guarantee the stable operation of the hybrid AC-DC power systems is a critical undertaking and technical demand.In view of the stability problems of hybrid AC-DC transmission systems with a high percentage of wind power,a hybrid AC・DC transmission system's stability control method that considers cross-region multi-energy coordination is established in this paper.Aiming at the uncertainty of a high percentage of wind power,the dynamic inversion method is used as the inner loop for robust control,and the battery energy storage and regenerative electric boiler are used as multiple energy sources to coordinate,and the outer loop robust control is used for uncertainty compensation.The hybrid AC-DC weak-sending terminal system with wind power is analyzed and designed by//-synthesis based on the Hg control,and a stability control method for hybrid AC-DC transmission systems,considering cross-region multi-energy coordination,is established.Simulation results show that the model proposed in this paper can guarantee the robustness of the dynamic inversion method and improves the control performance of AC-DC transmission systems.

Bioresponsive nanogated ensemble based on structure-switchable aptamer directed assembly and disassembly of gold nanoparticles from mesoporous silica supports

By taking advantage of recent advances in aptamer biology and nanotechnology, we developed a general approach for the design and fabrication of bioresponsive controlled delivery systems. It utilized the structure-switchable aptamer directed assembly and disassembly of gold nanoparticles from mesoporous silica supports, which enables the control of cargo release from the inside of the mesoporous nanoparticles specifically in the presence of target molecule.

A novel study of sulfur-absorption via samarium-doped cerium sorbent at high temperature

Sulfides existing in many gas mixtures of high temperature cases have a negative effect on various industrial applications.In this study,we present samarium-doped cerium(SDC) sorbent to remove H2 S at high temperature.Compared with pure CeO2,the SDC sorbent shows excellent ability in sulfur removal because of the positive effect of the doping of Sm.The H2 has a negative influence on sulfidation of the SDC sorbent and significantly shortens the breakthrough time,hence breakthrough sulfur capacity(BSC).The carbon monoxide present in the feed gas has no obvious effect on the sulfur-removal performance,A suitable samarium loading in SDC leads to an optimum interaction between metal oxide species and the surface oxygen vacancies,which results in an optimal adsorbed activity of reduced gas(H2,H2 S) and hence desulphurization performance.In addition,the SDC sorbents have a good regenerated ability by a simple calcination process.