Grassland-type ecosystem stability in China differs under the influence of drought and wet events

Ecological stability is a core issue in ecological research and holds significant implications forhumanity. The increased frequency and intensity of drought and wet climate events resulting from climatechange pose a major threat to global ecological stability. Variations in stability among different ecosystemshave been confirmed, but it remains unclear whether there are differences in stability within the sameterrestrial vegetation ecosystem under the influence of climate events in different directions and intensities.China's grassland ecosystem includes most grassland types and is a good choice for studying this issue.This study used the Standardized Precipitation Evapotranspiration Index-12 (SPEI-12) to identify thedirections and intensities of different types of climate events, and based on Normalized DifferenceVegetation Index (NDVI), calculated the resistance and resilience of different grassland types for 30consecutive years from 1990 to 2019 (resistance and resilience are important indicators to measurestability). Based on a traditional regression model, standardized methods were integrated to analyze theimpacts of the intensity and duration of drought and wet events on vegetation stability. The resultsshowed that meadow steppe exhibited the highest stability, while alpine steppe and desert steppe had thelowest overall stability. The stability of typical steppe, alpine meadow, temperate meadow was at anintermediate level. Regarding the impact of the duration and intensity of climate events on vegetationecosystem stability for the same grassland type, the resilience of desert steppe during drought was mainlyaffected by the duration. In contrast, the impact of intensity was not significant. However, alpine steppewas mainly affected by intensity in wet environments, and duration had no significant impact. Ourconclusions can provide decision support for the future grassland ecosystem governance.

Diversity of Arbuscular Mycorrhizal Fungi Associated with Six Rice Cultivars in Italian Agricultural Ecosystem Managed with Alternate Wetting and Drying

Alternate wetting and drying(AWD)system,in which water has been reduced by approximately 35%with an increased occurrence of beneficial arbuscular mycorrhizal(AM)symbiosis and no negative impact on rice yield,was proposed to utilize water and nutrients more sustainable.In this study,we selected six rice cultivars(Centauro,Loto,Selenio,Vialone nano,JSendra and Puntal)grown under AWD conditions,and investigated their responsiveness to AM colonization and how they select diverse AM taxa.In order to investigate root-associated AM fungus communities,molecular cloning-Sanger sequencing on small subunit rDNA data were obtained from five out of the six rice cultivars and compared with Next Generation Sequencing(NGS)data,which were previously obtained in Vialone nano.The results showed that all the cultivars were responsive to AM colonization with the development of AM symbiotic structures,even if with differences in the colonization and arbuscule abundance in the root systems.We identified 16 virtual taxa(VT)in the soil compartment and 7 VT in the root apparatus.We emphasized that the NGS analysis gives additional value to the results thanks to a more in-depth reading of the less represented AM fungus taxa.

Asymmetric Drying and Wetting Trends in Eastern and Western China

As an important factor that directly affects agricultural production, the social economy, and policy implementation,observed changes in dry/wet conditions have become a matter of widespread concern. However, previous research has mainly focused on the long-term linear changes of dry/wet conditions, while the detection and evolution of the non-linear trends related to dry/wet changes have received less attention. The non-linear trends of the annual aridity index, obtained by the Ensemble Empirical Mode Decomposition(EEMD) method, reveal that changes in dry/wet conditions in China are asymmetric and can be characterized by contrasting features in both time and space in China. Spatially, most areas in western China have experienced transitions from drying to wetting, while opposite changes have occurred in most areas of eastern China. Temporally, the transitions occurred earlier in western China compared to eastern China. Research into the asymmetric spatial characteristics of dry/wet conditions compensates for the inadequacies of previous studies, which focused solely on temporal evolution;at the same time, it remedies the inadequacies of traditional research on linear trends over centennial timescales. Analyzing the non-linear trend also provides for a more comprehensive understanding of the drying/wetting changes in China.

Hydrogen inhibition effect of chitosan and sodium phosphate on ZK60 waste dust in a wet dust removal system:A feasible way to control hydrogen explosion

Wet dust removal systems used to control dust in the polishing or grinding process of Mg alloy products are frequently associated with potential hydrogen explosion caused by magnesium-water reaction.For purpose of avoiding hydrogen explosion risks,we try to use a combination of chitosan(CS)and sodium phosphate(SP)to inhibit the hydrogen evolution reaction between magnesium alloy waste dust and water.The hydrogen evolution curves and chemical kinetics modeling for ten different mixing ratios demonstrate that 0.4wt%CS+0.1wt%SP yields the best inhibition efficiency with hydrogen generation rate of almost zero.SEM and EDS analyses indicate that this composite inhibitor can create a uniform,smooth,tight protective film over the surface of the alloy dust particles.FTIR and XRD analysis of the chemical composition of the surface film show that this protective film contains CS and SP chemically adsorbed on the surface of ZK60 but no detectable Mg(OH)_(2),suggesting that magnesium-water reaction was totally blocked.Our new method offers a thorough solution to hydrogen explosion by inhibiting the hydrogen generation of magnesium alloy waste dust in a wet dust removal system.

Wetting alternating with partial drying during grain filling increases lysine biosynthesis in inferior rice grain

Lysine content is a criterion of the nutritional quality of rice.Understanding the process of lysine biosynthesis in early-flowering superior grain(SG)and late-flowering inferior grain(IG)of rice would advance breeding and cultivation to improve nutritional quality.However,little information is available on differences in lysine anabolism between SG and IG and the underlying mechanism,and whether and how irrigation regimes affect lysine anabolism in these grains.A japonica rice cultivar was grown in the field and two irrigation regimes,continuous flooding(CF)and wetting alternating with partial drying(WAPD),were imposed from heading to the mature stage.Lysine content and activities of key enzymes of lysine biosynthesis,and levels of brassinosteroids(BRs)were lower in the IG than in the SG at the early grainfilling stage but higher at middle and late grain-filling stages.WAPD increased activities of these key enzymes,BR levels,and contents of lysine and total amino acids in IG,but not SG relative to CF.Application of 2,4-epibrassinolide to rice panicles in CF during early grain filling reproduced the effects of WAPD,but neither treatment altered the activities of enzymes responsible for lysine catabolism in either SG or IG.WAPD and elevated BR levels during grain filling increased lysine biosynthesis in IG.Improvement in lysine biosynthesis in rice should focus on IG.

Preparation of PrFe_(x)Co_(1-x)O_(3)/Mt catalyst and study on degradation of 2-hydroxybenzoic acid wastewater by catalytic wet peroxide oxidation

In this study,the perovskite nanocomposite PrFe_(x)Co_(1-x)O_(3)(Pr(S))was successfully synthesized by the sol-gel method;PrFe_(x)Co_(1-x)O_(3)/Al-pillared montmorillonite(Pr(S)/Mt)catalysts were prepared by impregnation(D)method and solid-melting(G)method,respectively,with Pr(S)as the active component and Al-pillared montmorillonite as the carrier.The catalysts were applied to treat the 2-hydroxybenzoic acid(2-HA)-simulated wastewater by catalytic wet peroxide oxidation(CWPO)technique,and the chemical oxygen demand(COD)removal rate and the 2-HA degradation rate were used as indicators to evaluate the catalytic performance.The results of the experiment indicated that the solid-melting method was more conducive to preparing the catalyst when the Co/Fe molar ratio of 7:3 and the optimal structural properties of the catalysts were achieved.The influence of operating parameters,including reaction temperature,catalyst dosage,H_(2)O_(2)dosage,pH,and initial 2-HA concentration,were optimized for the degradation of 2-HA by CWPO.The results showed that 97.64%of 2-HA degradation and 75.23%of COD removal rate were achieved under more suitable experimental conditions.In addition,after the catalyst was used five times,the degradation rate of 2-HA could still reach 76.93%,which implied the high stability and reusability of the catalyst.The high catalytic activity of the catalyst was due to the doping of Co into PrFeO_(3),which could promote the generation of HO·,and the high stability could be attributed to the loading of Pr(S)onto Al-Mt,which reduced the leaching of reactive metals.The study of reaction mechanism and kinetics showed that the whole degradation process conformed to the pseudo-firstorder kinetic equation,and the Langmuir-Hinshelwood method was applied to demonstrate that catalysis was dominant in the degradation process.

Characteristics and Mechanisms of Persistent Wet–Cold Events with Different Cold-air Paths in South China

We investigate the characteristics and mechanisms of persistent wet–cold events(PWCEs)with different types of coldair paths.Results show that the cumulative single-station frequency of the PWCEs in the western part of South China is higher than that in the eastern part.The pattern of single-station frequency of the PWCEs are“Yangtze River(YR)uniform”and“east–west inverse”.The YR uniform pattern is the dominant mode,so we focus on this pattern.The cold-air paths for PWCEs of the YR uniform pattern are divided into three types—namely,the west,northwest and north types—among which the west type accounts for the largest proportion.The differences in atmospheric circulation of the PWCEs under the three types of paths are obvious.The thermal inversion layer in the lower troposphere is favorable for precipitation during the PWCEs.The positive water vapor budget for the three types of PWCEs mainly appears at the southern boundary.

Extended wet sieving method for determination of complete particle size distribution of general soils

The traditional standard wet sieving method uses steel sieves with aperture?0.063 mm and can only determine the particle size distribution(PSD)of gravel and sand in general soil.This paper extends the traditional method and presents an extended wet sieving method.The extended method uses both the steel sieves and the nylon filter cloth sieves.The apertures of the cloth sieves are smaller than 0.063 mm and equal 0.048 mm,0.038 mm,0.014 mm,0.012 mm,0.0063 mm,0.004 mm,0.003 mm,0.002 mm,and 0.001 mm,respectively.The extended method uses five steps to separate the general soil into many material sub-groups of gravel,sand,silt and clay with known particle size ranges.The complete PSD of the general soil is then calculated from the dry masses of the individual material sub-groups.The extended method is demonstrated with a general soil of completely decomposed granite(CDG)in Hong Kong,China.The silt and clay materials with different particle size ranges are further examined,checked and verified using stereomicroscopic observation,physical and chemical property tests.The results further confirm the correctness of the extended wet sieving method.

Reservoir quality evaluation of the Narimba Formation in Bass Basin,Australia:Implications from petrophysical analysis,sedimentological features,capillary pressure and wetting fluid saturation

The evaluation of reservoir quality was accomplished on the Late Paleocene to Early Eocene Narimba Formation in Bass Basin,Australia.This study involved combination methods such as petrophysical analysis,petrography and sedimentological studies,reservoir quality and fluid flow units from derivative parameters,and capillary pressure and wetting fluid saturation relationship.Textural and diagenetic features are affecting the reservoir quality.Cementation,compaction,and presence of clay minerals such as kaolinite are found to reduce the quality while dissolution and secondary porosity are noticed to improve it.It is believed that the Narimba Formation is a potential reservoir with a wide range of porosity and permeability.Porosity ranges from 3.1%to 25.4%with a mean of 15.84%,while permeability ranges between 0.01 mD and 510 mD,with a mean of 31.05 mD.Based on the heterogenous lithology,the formation has been categorized into five groups based on permeability variations.Group I showed an excellent to good quality reservoir with coarse grains.The impacts of both textural and diagenetic features improve the reservoir and producing higher reservoir quality index(RQI)and flow zone indicators(FZI)as well as mostly mega pores.The non-wetting fluid migration has the higher possibility to flow in the formation while displacement pressure recorded as zero.Group II showed a fair quality reservoir with lower petrophysical properties in macro pores.The irreducible water saturation is increasing while the textural and digenetic properties are still enhancing the reservoir quality.Group III reflects lower quality reservoir with mostly macro pores and higher displacement pressure.It may indicate smaller grain size and increasing amount of cement and clay minerals.Group IV,and V are interpreted as a poor-quality reservoir that has lower RQI and FZI.The textural and digenetic features are negatively affecting the reservoir and are leading to smaller pore size and pore throat radii(r35)values to be within the range of macro,meso-,micro-,and nano pores.The capillary displacement pressure curves of the three groups show increases reaching the maximum value of 400 psia in group V.Agreement with the classification of permeability,r35 values,and pore type can be used in identifying the quality of reservoir.

Utility of real-time 3D visualization system in the early stage of phacoemulsification training

●AIM:To determine the teaching effects of a real-time three dimensional(3D)visualization system in the operating room for early-stage phacoemulsification training.●METHODS:A total of 10 ophthalmology residents of the first-year postgraduate were included.All the residents were novices to cataract surgery.Real-time cataract surgical observations were performed using a custom-built 3D visualization system.The training lasted 4wk(32h)in all.A modified International Council of Ophthalmology’s Ophthalmology Surgical Competency Assessment Rubric(ICO-OSCAR)containing 4 specific steps of cataract surgery was applied.The self-assessment(self)and expert-assessment(expert)were performed through the microsurgical attempts in the wet lab for each participant.●RESULTS:Compared with pre-training assessments(self 3.2±0.8,expert 2.5±0.6),the overall mean scores of posttraining(self 5.2±0.4,expert 4.7±0.6)were significantly improved after real-time observation training of 3D visualization system(P<0.05).Scores of 4 surgical items were significantly improved both self and expert assessment after training(P<0.05).●CONCLUSION:The 3D observation training provides novice ophthalmic residents with a better understanding of intraocular microsurgical techniques.It is a useful tool to improve teaching efficiency of surgical education.

Preparation of Regenerated Silk Fibroin Hybrid Fibers with Hydrogen Peroxide Sensing Properties by Wet Spinning

Silk is widely used in the production of high-quality textiles.At the same time,the amount of silk textiles no longer in use and discarded is increasing,resulting in significant waste and pollution.This issue is of great concern in many countries where silk is used.Hydrogen peroxide as a naturally occurring compound is an important indicator of detection in both biology and the environment.This study aims to develop a composite fiber with hydrogen peroxide-sensing properties using discarded silk materials.To achieve this goal,firstly,polydopamine(PDA)was used to encapsulate the ZnFe_(2)O_(4) NPs to achieve the improvement of dispersion,and then regenerated silk fibroin(RSF)and PDA@ZnFe_(2)O_(4)/RSF hybrid fibers are prepared by wet spinning.Research has shown that PDA@ZnFe_(2)O_(4)/RSF demonstrates exceptional sensitivity,selectivity,and stability in detecting hydrogen peroxide,while maintaining high mechanical strength.Furthermore,the complete hybridization of PDA@ZnFe_(2)O_(4) with silk fibroin not only results in the combination of the durability of silk fibroin and PDA@ZnFe_(2)O_(4)’s rigidity,ensuring a reliable service life,but also makes PDA@ZnFe_(2)O_(4)/RSF exhibit excellent catalytic activity and biocompatibility.Therefore,the composite fiber exhibits exceptional mechanical properties and reliable hydrogen peroxide sensing capabilities,making it a promising material for biological and medical applications.

Subconjunctival hemorrhage after wet cupping therapy: a case report

Introduction:Cupping therapy is an integrative and complementary medicine therapy that practiced worldwide by several civilizations for thousands of years.Cupping therapy is reported to be a relatively safe practice especially if performed by qualified therapists.Subconjunctival hemorrhage(SCH)is a common cause of eye redness and can be classified into traumatic and spontaneous.Case presentation:This case report discussed an adverse event related to wet cupping therapy.The patient developed SCH one day after performing cupping therapy.He was completely recovered after 2 weeks.This case report should increase the knowledge of cupping therapists regarding increasing safety of patient when performing wet cupping therapy on specific body parts especially,head,neck and cervical areas.Furthermore,it highlighted the importance of conducting research regarding the mechanical and physiological effects of cupping therapy.Conclusion:Adverse events related to cupping therapy should be reported with every patient.Cupping therapists should be aware of this possible mild adverse event.To the best of our knowledge,this is the first published adult case of SCH related to wet cupping therapy session.More studies are critically needed for evaluation of cupping therapy effects and adverse events especially when performed on head and neck.

Tropospheric Wet Refractivity Tomography Based on the BeiDou Satellite System

This paper presents a novel approach for assessing the precision of the wet refractivity field using BDS （BeiDou navigation satellite system） simulations only,GPS,and BDS＋GPS for the Shenzhen and Hongkong GNSS network.The simulations are carried out by adding artificial noise to a real observation dataset.Instead of using the δ and σ parameters computed from slant wet delay,as in previous studies,we employ the Bias and RMS parameters,computed from the tomography results of total voxels,in order to obtain a more direct and comprehensive evaluation of the precision of the refractivity field determination.The results show that：（1） the precision of tropospheric wet refractivity estimated using BDS alone （only 9 satellites used） is basically comparable to that of GPS; （2） BDS＋GPS （as of current operation） may not be able to significantly improve the data＇s spatial density for the application of refractivity tomography; and （3） any slight increase in the precision of refractivity tomography,particularly in the lower atmosphere,bears great significance for any applications dependent on the Chinese operational meteorological service.

Fault Tree Analysis of Dust Suppression Mechanism in a Spray System with Wetting Agent

By using the fault tree analysis in reliability theory as the systematical analysis approach, the dust suppression mechanism in a spray system with wetting agent is shown in a logic tree and some graphical models. From these diagrams, all factors related to the spray system and their cause and effect relationship can be seen clearly. Based on the built logic tree, several mathematical models and new ideas for expressing the dust suppressing efficiency in the spray system are put forward. The significance of all factors related to the efficiency of suppressing dust is qualitatively described. Furthermore, the new concepts, such as, the effective reaction time between dust particle and droplet, the expansion phenomenon of laden dust droplet, the functions of volatile and the relative size distribution efficiency of wetting agent are presented. All this richenes the existing mechanism of dust abatement by spraying wetting agent. At last, several problems that need to be further investigated are also suggested in the paper.

Reactive wetting behaviors of Sn/Cu systems: A molecular dynamics study

Influences of temperature and Sn-Cu droplet's composition on reactive wettings of Cu(100), Cu(110), and Cu(111) surfaces were analyzed, by using molecular dynamics(MD) calculations. As a result, the spreading on Cu(110)(Cu(100)) has the fastest(slowest) wetting kinetics. A higher temperature or a diluter Cu content in the Sn-Cu alloy droplet results in a higher wettability. Moreover, this work has addressed a theory for positioning the interface separating the liquidus and solidus alloys in the spreading film to confirm the hypothesis that the reactive wetting will come to the end when the interface saturates with the temperature-dependent solidus weight fraction of Cu.

DEM modeling of high shear wet granulation of a simple system

High shear wet granulation(HSWG) is one of the most poorly understood processes with known difficulties in optimization and scale up. The purpose of the current study is to develop a DEM model which can be applied under dynamic process conditions with high predictive capacity to improve process insight. The DEM model is used to predict agglomeration as a function of impeller speed and liquid addition rate in a high shear wet granulator. The DEM model tracks dynamic formation and breakage of liquid bridges between particles as liquid binder in the system is added, and corrects for the change in material properties as a function of the binder content.

Latest developments for dry and wet dedusting systems for converter steel making

Environmental requirements world wide and in the P.R.of China in particular have increased and authorities are increasing the pressure on steelmakers to comply with always more stringent limits and standards. Modern converter steel making goes along with the innovation and new developments not only for the primary converter process itself but even more for the dedusting technologies.This paper describes the benefits and latest development of advanced off gas cleaning and recovery systems based on dry type cleaning with electrostatic precipitation and wet type gas cleaning based on wet scrubbers.Modern converter dedusting is based on suppressed combustion systems in order to reduce off gas amounts and to be able to use the gas for gas recovery.The dry type primary off gas treatment system based on electrostatic precipitator technology is the most advanced environmental solution available for converter steel making.Dry dedusting has been introduced in China successfully with a significant contribution by Siemens VAI being the market leader for converter dry dedusting systems.Siemens VAI has introduced several design improvements over the last years such as CFD modeling of flow conditions in evaporation cooler,design of chains for dust conveyors,design of ESP inlet,design and thickness of discharge electrodes and operation in energy saving mode.Additionally the DDS process has been successfully implemented in China for the De-P process.The gas recovery system for DDS has been optimized over the years with high quality equipment and integrated automation and control systems.Wet type dedusting for converter gas is a well proven technology for many years and is still widely used due to the simplicity of the process and the lower investment costs.SVAI has continuously improved it's wet dedusting technologies to provide highly energy efficient systems which can achieve lowest levels of clean gas dust while still maintaining a moderate water and energy consumption with simplified process control and standardized process control packages.Main design and process improvements include expansion joints for connection of scrubber to cooling stack,new type of droplet separator,advanced hood pressure control package,ID fan washing system,ID fan speed control system etc.The focus for wet type gas recovery systems is still on maximum safety and reliability.SVAI has also successfully improved the technological packages for converter gas recovery for wet type dedusting systems.The comparison between the two system shows the advantages of dry dedusting mainly being the lowest clean gas dust content, lower operating costs,easier handling for recycling of residuals and no need for a water treatment plants.Wet type dedusting has it's main advantages in the simple process and operation of the system,the flexible layout solutions inside the steel shop as well as generally lower investment costs.An overview on the numerous reference installations for dry- and wet type dedusting systems in China as well as world wide is given.

Dynamic optimization oriented modeling and nonlinear model predictive control of the wet limestone FGD system

Nonlinear model predictive control(NMPC)scheme is an effective method of multi-objective optimization control in complex industrial systems.In this paper,a NMPC scheme for the wet limestone flue gas desulphurization(WFGD)system is proposed which provides a more flexible framework of optimal control and decision-making compared with PID scheme.At first,a mathematical model of the FGD process is deduced which is suitable for NMPC structure.To equipoise the model’s accuracy and conciseness,the wet limestone FGD system is separated into several modules.Based on the conservation laws,a model with reasonable simplification is developed to describe dynamics of different modules for the purpose of controller design.Then,by addressing economic objectives directly into the NMPC scheme,the NMPC controller can minimize economic cost and track the set-point simultaneously.The accuracy of model is validated by the field data of a 1000 MW thermal power plant in Henan Province,China.The simulation results show that the NMPC strategy improves the economic performance and ensures the emission requirement at the same time.In the meantime,the control scheme satisfies the multiobjective control requirements under complex operation conditions(e.g.,boiler load fluctuation and set point variation).The mathematical model and NMPC structure provides the basic work for the future development of advanced optimized control algorithms in the wet limestone FGD systems.

Mechanism of wet shotcrete interacting with rock in support systems

In order to have a good understanding of the behavior of wet shotcrete as a support element interacting with the rock mass,mechanism of wet shotcrete interacting with rock in support systems was analyzed through theoretical,numerical study and analytical analysis.A new model of distribution of rock stress state after wet shotcrete was applied,which includes shotcrete layer,composite layer,strengthening layer,plastic layer and elastic layer,and a full illustration of the rock mass stress state was given after shotcrete interacting with rock mass.At the same time,numerical analysis with FLAC gives a stress distribution along the monitor line,respectively,at the sidewall and roof of the tunnel.The displacement obviously decreases with the depth of rock,the tangential stress for tunnel supported by shotcrete is lower than that without shotcrete,and radial stress for tunnel supported by shotcrete is higher than that without shotcrete.It has been demonstrated by AIRY'S stress function,which gives a reasonable solution.Finally,the application of wet shotcrete in Jinfeng Gold Mine shows that the displacement of tunnel decreases obviously in sidewall and roof.

Development of underwater wet welding experimental and divers training system

Compared to traditional welding methods, the underwater wet welding is special with many different characteristics due to the unique aqueous environment. It is conducted completely under water by divers and unique welding technology is required in the special operation environment. The operating levels of the divers are the key factor to acquire high quality welded joints. In this paper, an underwater wet welding experimental and divers training system is developed to serve divers training and conducting welding experiments. The system consists of life support system, signals real-time monitoring system and communicating system, etc. An underwater butt welding experiment based on welding electrodes is conducted, and the system works well. It proves that the system can guarantee divers welding safely and successfully and high quality weld seam is expected to be acquired.