Flood disasters can have a serious impact on people's production and lives, and can cause hugelosses in lives and property security. Based on multi-source remote sensing data, this study establisheddecision tree c...Flood disasters can have a serious impact on people's production and lives, and can cause hugelosses in lives and property security. Based on multi-source remote sensing data, this study establisheddecision tree classification rules through multi-source and multi-temporal feature fusion, classified groundobjects before the disaster and extracted flood information in the disaster area based on optical imagesduring the disaster, so as to achieve rapid acquisition of the disaster situation of each disaster bearing object.In the case of Qianliang Lake, which suffered from flooding in 2020, the results show that decision treeclassification algorithms based on multi-temporal features can effectively integrate multi-temporal and multispectralinformation to overcome the shortcomings of single-temporal image classification and achieveground-truth object classification.展开更多
In this paper,the Multi-Temporal Interferometric Synthetic Aperture Radar(MT-InSAR)technology is adopted to monitor the Line of Sight(LOS)displacement of Fushun West Opencast Coal Mine(FWOCM)and its surrounding areas ...In this paper,the Multi-Temporal Interferometric Synthetic Aperture Radar(MT-InSAR)technology is adopted to monitor the Line of Sight(LOS)displacement of Fushun West Opencast Coal Mine(FWOCM)and its surrounding areas in northeast China using Sentinel-1 Synthetic Aperture Radar(SAR)images acquired from 2018 to 2022.The spatial-temporal evolution of urban subsidence and the south-slope landslide are both analyzed in detail.Comparison with ground measurements and cross-correlation analysis via cross wavelet transform with monthly precipitation data are also conducted,to analyze the influence factors of displacements in FWOCM.The monitoring results show that a subsidence basin appeared in the urban area near the eastern part of the north slope in 2018,with settlement center located at the intersection of E3000 and fault F1.The Qian Tai Shan(QTS)landslide on the south slope,which experienced rapid sliding during 2014 to 2016,presents seasonal deceleration and acceleration with precipitation,with the maximum displacement in vicinity of the Liushan paleochannel.The results of this paper have fully taken in account for the complications of large topographic relief,geological conditions,spatial distribution and temporal evolution characteristics of surface displacements in opencast mining area.The wide range and long time series dynamic monitoring of opencast mine are of great significance to ensure mine safety production and geological disaster prevention in the investigated mining area.展开更多
Creation of a spectral signature reflectance data, which aids in the identification of the crops is important in determining size and location crop fields. Therefore, we developed a spectral signature reflectance for ...Creation of a spectral signature reflectance data, which aids in the identification of the crops is important in determining size and location crop fields. Therefore, we developed a spectral signature reflectance for the vegetative stage of the green gram (Vigna. radiata L.) over 5 years (2020, 2018, 2017, 2015, and 2013) for agroecological zone IV and V in Kenya. The years chosen were those whose satellite resolution data was available for the vegetative stage of crop growth in the short rain season (October, November, December (OND)). We used Landsat 8 OLI satellite imagery in this study. Cropping pattern data for the study area were evaluated by calculating the Top of Atmosphere reflectance. Farms geo-referencing, along with field data collection, was undertaken to extract Top of Atmosphere reflectance for bands 2, 3, 4 and 7. We also carried a spectral similarity assessment on the various cropping patterns. The spectral reflectance ranged from 0.07696 - 0.09632, 0.07466 - 0.09467, 0.0704047 - 0.12188,0.19822 - 0.24387, 0.19269 - 0.26900, and 0.11354 - 0.20815 for bands 2, 3, 4, 5, 6, and 7 for green gram, respectively. The results showed a dissimilarity among the various cropping patterns. The lowest dissimilarity index was 0.027 for the maize (Zea mays L.) bean (Phaseolus vulgaris) versus the maize-pigeon pea (Cajanus cajan) crop, while the highest dissimilarity index was 0.443 for the maize bean versus the maize bean and cowpea cropping patterns. High crop dissimilarities experienced across the cropping pattern through these spectral reflectance values confirm that the green gram was potentially identifiable. The results can be used in crop type identification in agroecological lower midland zone IV and V for mung bean management. This study therefore suggests that use of reflectance data in remote sensing of agricultural ecosystems would aid in planning, management, and crop allocation to different ecozones.展开更多
In this study,the effects of different salinity gradients and addition of compatible solutes on anaerobic treated effluent water qualities,sludge characteristics and microbial communities were investigated.The increas...In this study,the effects of different salinity gradients and addition of compatible solutes on anaerobic treated effluent water qualities,sludge characteristics and microbial communities were investigated.The increase in salinity resulted in a decrease in particle size of the granular sludge,which was concentrated in the range of 0.5-1.0 mm.The content of EPS(extracellular polymeric substances)in the granular sludge gradually increased with increasing salinity and the addition of betaine(a typical compatible solute).Meanwhile,the microbial community structure was significantly affected by salinity,with high salinity reducing the diversity of bacteria.At higher salinity,Patescibacteria and Proteobacteria gradually became the dominant phylum,with relative abundance increasing to 13.53%and 12.16%at 20 g/L salinity.Desulfobacterota and its subordinate Desulfovibrio,which secrete EPS in large quantities,dominated significantly after betaine addition.Their relative abundance reached 13.65%and 7.86%at phylum level and genus level.The effect of these changes on the treated effluent was shown as the average chemical oxygen demand(COD)removal rate decreased from 82.10%to 79.71%,78.01%,68.51%and 64.55%when the salinity gradually increased from 2 g/L to 6,10,16 and 20 g/L.At the salinity of 20 g/L,average COD removal increased to 71.65%by the addition of 2 mmol/L betaine.The gradient elevated salinity and the exogenous addition of betaine played an important role in achieving stability of the anaerobic system in a highly saline environment,which provided a feasible strategy for anaerobic treatment of organic saline wastewater.展开更多
Objective To investigate whether 2,3,5,4'-tetrahydroxystilbene-2-O-β-glucoside(TSG)ameliorated polycystic ovary syndrome(PCOS)-like characteristics by inhibiting inflammation.Methods PCOS models were established ...Objective To investigate whether 2,3,5,4'-tetrahydroxystilbene-2-O-β-glucoside(TSG)ameliorated polycystic ovary syndrome(PCOS)-like characteristics by inhibiting inflammation.Methods PCOS models were established by injecting subcutaneously with dehydroepiandrosterone into female Sprague-Dawley rats,followed by receiving intraperitoneal injection of TSG.The granular cells(GCs)KGN were transfected with small interfering RNAs(si-NC and si-CYP19A1).The cells were preincubated with lipopolysaccharide(LPS)and then treated with or without TSG.The estrous cycle was monitored using vaginal exfoliated cells.The morphology of ovarian follicles was analyzed by H&E staining.ELISA was used to analyze estradiol(E2),testosterone(T),follicle stimulating hormone(FSH),luteinizing hormone(LH),IL-6,TNF-α,AGEs,CRP and Omentin-1 levels in serum.Immunohistochemistry was performed to analyze PCNA and CYP19A1 expressions in the GCs of ovaries.Tunel staining was executed to detect the apoptosis of GCs.Quantitative polymerase chain reaction(qPCR)and Western blot were implemented to measure the expression of CYP19A1 in the ovaries and transfected cells.qPCR was used to analyze the expression of IL-6 and TNF-αin the transfected cells treated with LPS and TSG.Results The estrous cycles were restored in TSG group.Compared with model group,the sinus follicles were reduced and corpus luteums were increased in TSG group.TSG group showed increased E2,and decreased T and LH,compared with model group.Pro-inflammatory factors(IL-6,TNF-α,CRP and AGEs)were decreased,and anti-inflammatory factor(Omentin-1)was increased in TSG group compared with those in model group.TSG could partially inhibit decrease of PNCA-positive GCs and increase of Tunel-positive GCs caused by PCOS.The CYP19A1 expression of GCs in TSG group was upregulated compared with model group.The expressions of IL-6 and TNFαin si-CYP19A1 cells were increased compared with si-NC cells.Compared with cells(si-NC and si-CYP19A1)treated without LPS,the expressions of IL-6 and TNF-αcells were increased,and the expression of CYP19A1 was downregulated in LPS-preincubated cells.Compared with cells treated with LPS,the expression of IL-6 and TNF-αwere decreased,and the expression of CYP19A1 was increased in cells treated with LPS and TSG.Compared with si-NC cells treated with LPS and TSG,the expressions of IL-6 and TNF-αcells were increased in the si-CYP19A1 cells treated with LPS and TSG.Conclusion TSG could alleviate PCOS-like characteristics by increasing the expression of CYP19A1 in GCs to inhibit inflammatory response.展开更多
The two universes multi-granularity fuzzy rough set model is an effective tool for handling uncertainty problems between two domains with the help of binary fuzzy relations. This article applies the idea of neighborho...The two universes multi-granularity fuzzy rough set model is an effective tool for handling uncertainty problems between two domains with the help of binary fuzzy relations. This article applies the idea of neighborhood rough sets to two universes multi-granularity fuzzy rough sets, and discusses the two-universes multi-granularity neighborhood fuzzy rough set model. Firstly, the upper and lower approximation operators are defined in the two universes multi-granularity neighborhood fuzzy rough set model. Secondly, the properties of the upper and lower approximation operators are discussed. Finally, the properties of the two universes multi-granularity neighborhood fuzzy rough set model are verified through case studies.展开更多
The pandemic SARS-CoV-2 has become an undying virus to spread a sustainable disease named COVID-19 for upcoming few years.Mortality rates are rising rapidly as approved drugs are not yet available.Isolation from the i...The pandemic SARS-CoV-2 has become an undying virus to spread a sustainable disease named COVID-19 for upcoming few years.Mortality rates are rising rapidly as approved drugs are not yet available.Isolation from the infected person or community is the preferred choice to protect our health.Since humans are the only carriers,it might be possible to control the positive rate if the infected population or host carriers are isolated from each other.Isolation alone may not be a proper solution.These are the resolutions of previous research work carried out on COVID-19 throughout the world.The present scenario of the world and public health is knocking hard with a big question of critical uncertainty of COVID-19 because of its imprecise database as per daily positive cases recorded all over the world and in India as well.In this research work,we have pre-sented an optimal control model for COVID-19 using granular differentiability based on fuzzy dynamical systems.In the first step,we created a fuzzy Susceptible-Exposed-Infected-Asymptomatic-Hospitalized-Recovered-Death(SEIAHRD)model for COVID-19,analyzed it using granular differentiability,and reported disease dynamics for time-independent disease control parameters.In the second step,we upgraded the fuzzy dynamical system and granular differentiability model related to time-dependent disease control parameters as an optimal control problem invader.Theoretical studies have been validated with some practical data from the epidemic COVID-19 related to the Indian perspective during first wave and early second wave.展开更多
When a vehicle moves over a flexible pavement structure,it generates loading and unloading cycles that produce recoverable(resilient)and permanent(plastic)deformations in the granular base and subbase layers,which are...When a vehicle moves over a flexible pavement structure,it generates loading and unloading cycles that produce recoverable(resilient)and permanent(plastic)deformations in the granular base and subbase layers,which are made of unbound granular materials(UGMs).The primary parameter used to evaluate the resilient response of UGMs in pavements is the resilient modulus(MR).The MR is widely used in calculating stress-strain states for flexible pavement design and as a control parameter during the construction process.It is also employed to understand the progression of distresses,such as fatigue cracking and rutting.The main objective of this study was to conduct a literature review on the resilient behavior of UGMs.This manuscript presents and describes the MR and the factors that influence it.It also outlines the evolution of the mathematical equations most commonly used to estimate and predict this physical parameter.Conclusions and recommendations for future research are provided at the end of the article.Despite the large amount of research done on the subject,the resilient behavior of UGM has not yet been fully understood.This is since these materials are highly heterogeneous and show nonlinear-anisotropic behavior under different cyclic loading paths and water contents.Likewise,these materials undergo different behaviors depending on their macro and microscopic properties(gradation,density,porosity,texture,mineralogy,particle geometry and orientation,temperature,among others).On the other hand,the main limitation of the mathematical equations is that their parameters are difficult to determine experimentally and are not constants of the material(they are state variables that can change with multiple factors).Additionally,these equations do not consider the boundary conditions to which UGM in pavements are exposed.Moreover,they are obtained from repeated load triaxial(RLT)tests,which cannot simulate the three cyclic stress components(vertical,horizontal,and shear)to which UGMs are subjected in a pavement.In recent years,there has been an increase in studies evaluating the use of recycled aggregates and the effect of temperature(particularly at subzero temperatures),but more research is still needed to reach definitive conclusions.展开更多
Based on the energy dissipation caused by consolidation deformation of the porous media under external force and migration of the internal suspended substances,a coupled multiphase-substance flow(CMF)model was establi...Based on the energy dissipation caused by consolidation deformation of the porous media under external force and migration of the internal suspended substances,a coupled multiphase-substance flow(CMF)model was established.This model introduced the new concepts,such as particle temperature and particle entropy,to describe energy dissipation at meso-level.This model used a potential energy density function and migration coefficients to establish the corresponding connection between the dissipative force and dissipative flow.This viewpoint unifies the deformation,seepage,and suspended substance migration of geotechnical materials under the framework of granular thermodynamics.It can reflect the evolution of effective stress in the solid matrix of multi-components in a particle-reorganized state,and considers the temperature driving effect.The proposed CMF model is validated using the experimental results under coupled migration of heavy metal ions(HMs)and suspended particles(SPs).The calculation results demonstrated that the CMF model can describe the flow process under the conditions of arbitrary changes in different suspended substance types,injection concentrations,and injection velocities.展开更多
The dynamics of fluid and non-buoyant particles in a librating horizontal annulus is studied experimentally.In the absence of librations,the granular material forms a cylindrical layer near the outer boundary of the a...The dynamics of fluid and non-buoyant particles in a librating horizontal annulus is studied experimentally.In the absence of librations,the granular material forms a cylindrical layer near the outer boundary of the annulus and undergoes rigid-body rotation with the fluid and the annulus.It is demonstrated that the librational liquefaction of the granular material results in pattern formation.This self-organization process stems from the excitation of inertial modes induced by the oscillatory motion of liquefied granular material under the influence of the gravitational force.The inertial wave induces vortical fluid flow which entrains particles from rest and forms eroded areas that are equidistant from each other along the axis of rotation.Theoretical analysis and experiments demonstrate that a liquefied layer of granular material oscillates with a radian frequency equal to the angular velocity of the annulus and interacts with the inertial wave it excites.The new phenomenon of libration-induced pattern formation is of practical interest as it can be used to control multiphase flows and mass transfer in rotating containers in a variety of industrial processes.展开更多
In the deep geological disposal repository of high-level radioactive waste,buffer/backfill materials typically consist of compacted bentonite block and granular bentonite.As these materials undergo a long-term hydrati...In the deep geological disposal repository of high-level radioactive waste,buffer/backfill materials typically consist of compacted bentonite block and granular bentonite.As these materials undergo a long-term hydration,it is anticipated that the two forms of bentonite materials(i.e.compacted bentonite powder(CBP)and granular bentonite(GB))are expected to exhibit differing hydro-mechanical behaviors due to the differences in their structures.This work aims to investigate the differences in swelling pressure and compressibility through a series of swelling pressure tests,compression tests and mercury intrusion porosimetry(MIP)tests.The experimental results demonstrated that swelling pressure curves of the CBP specimens showed higher first peak values and more pronounced collapse than those of the GB specimens at a given dry density,regardless of vapor-water hydration or liquid-water hydration.The final swelling pressures of the two materials were similar at the same dry density,suggesting an independent correlation between swelling pressure and dry density.At the high suction range,the compression curves exhibited an obvious bi-linear pattern for the CBP specimens and a significant nonlinearity for the GB specimens.Meanwhile,the CBP specimens presented higher pre-consolidation pressures and larger compression indices than the GB specimens at a given suction.As suction decreased,the compression curves of the two materials gradually approached each other and their differences were reduced accordingly.After reaching saturation,a good consistency between them was observed whether for final swelling pressure or compressibility.Pore structure analysis revealed that the two materials both presented an initially double structure,and their differences were primarily manifested at the macrostructural level.Eventually,the differences in swelling pressure or compression curves of the two materials were well interpreted by combining microstructural evolutions.展开更多
Bridge pier failures from granular flow impacts are common.Installing defense piles upstream is an effective mitigation strategy,yet their protective mechanisms and standardized design guidelines are unclear.This stud...Bridge pier failures from granular flow impacts are common.Installing defense piles upstream is an effective mitigation strategy,yet their protective mechanisms and standardized design guidelines are unclear.This study employed 3D discrete element method to analyze the influence of defense pile size and placement on its performance across 219 scenarios,providing a detailed examination of their protective mechanisms.Results show that optimizing these factors can reduce the maximum impact force on bridge piers by up to 94%.In terms of size,a critical height threshold is identified,beyond which increasing pile height does not enhance protection.This threshold depends on the movement height of granular particles at the slope base.Protection effectiveness varies with pile size:when H≤0.05 h(H is the height of defense piles,h is the height of bridge),protection marginally improves with increasing height and diameter;for 0.05 h<H<0.15 h,protection strongly correlates with both parameters;for H≥0.15 h,diameter becomes the dominant factor.In terms of placement,an optimal longitudinal distance exists between the defense pile and the bridge pier.The larger the diameter,the greater the optimal longitudinal distance.However,the transverse distance is inversely related to protection effectiveness.Mechanistic analysis shows that defense piles are more effective at redirecting particles to prevent direct collisions with the pier(contributing 100%impact energy reduction before the non-dimensional travel time t*=7.01 and 63%–100%afterward)than at reducing particle velocity.This study provides insights into the protective mechanisms of defense piles and informs strategies for optimizing bridge pier protection in granular flow-prone regions.展开更多
Granular composite(GC)hydrogels have attracted considerable interest in biomedical applications due to their versatile printability and exceptional mechanical properties.However,the lack of comprehensive design guidel...Granular composite(GC)hydrogels have attracted considerable interest in biomedical applications due to their versatile printability and exceptional mechanical properties.However,the lack of comprehensive design guidelines has limited their optimal engineering,as the factors influencing their mechanical performance and printability remain largely unexamined.In this study,we developed GC hydrogels by integrating microgels with interstitial matrices of photocrosslinkable gelatin methacrylate(GelMA).We utilized confocal microscopy and nanoindentation analyses to investigate the spatial distribution and mechanical behavior of these hydrogels.Our findings indicate that the mechanical and rheological properties of GC hydrogels can be precisely tailored by adjusting the volume fraction and size of the microgels.Furthermore,hydrogen bonds were identified as significant contributors to compressive performance,although they had minimal effect on cyclic mechanical behavior.Compared to bulk GelMA hydrogels,GC hydrogels demonstrated enhanced printability and remarkable superelasticity.As a proof of concept,we illustrated their dual printability in embedded printing to create prosthetic liver models for preoperative planning.This study provides valuable insights into the design and optimization of GC hydrogels for advanced biomedical applications.展开更多
Red anaerobic ammonia oxidation (Anammox) granular sludge (AnGS) has been reported insuccessfully operating Anammox systems, and its color is associated with sludge activity.However, in long-term operating systems, An...Red anaerobic ammonia oxidation (Anammox) granular sludge (AnGS) has been reported insuccessfully operating Anammox systems, and its color is associated with sludge activity.However, in long-term operating systems, AnGS exhibits different sensory colors, physicalstructures, community structures, and denitrification performance, but the relationship betweenthem has not yet been elucidated.The AnGS of the Anammox system, which has beenin operation for more than a decade, can be divided into twomain categories: red and white.The specific Anammox activity (SAA) in conventional red AnGS increased continuously asthe particle size increased from <0.51 mm to 6.02 ± 0.84 mm. The SAA of white AnGS wereslightly lower than those of red AnGS with similarly-size granules but significantly higherthan AnGS with smaller red granules. Compared with red AnGS, the extracellular polymericsubstances of white AnGS were significantly reduced,mainly due to the higher intracellulariron content, resulting in lower heme c concentration. Thus, heme c may prove not to bean evaluative tool for measuring Anammox activity. Red and white AnGS, whether throughself-aggregation or adsorption by hydroxyl apatite and other carriers, will face the fate ofinternal voids during particle size growth. White AnGS exhibited amore complex microbialcommunity than red AnGS. Candidatus Brocadia was abundant in red AnGS and the abundanceincreased with increasing granule size. Candidatus Kuenenia and Candidatus Jetteniamade significant contributions to denitrification in white AnGS. This study provides a newperspective on particle selection for anammox engineering applications.展开更多
Granular sludges can resist the toxicity inhibition of medium-chain fatty acids(MCFAs)and enhance the chain elongation(CE)process.However,the granulation process is time-consuming and requires a suitable facilitating ...Granular sludges can resist the toxicity inhibition of medium-chain fatty acids(MCFAs)and enhance the chain elongation(CE)process.However,the granulation process is time-consuming and requires a suitable facilitating granulation mean.This study proposed two continuous fed Expanded Granular Sludge Bed bioreactors,one with electric field(EF)and one without,to demonstrate the promotion of sludge granulation by EF and the enhancement of MCFAs production efficiency by the anaerobic granular sludge(An GS).Through more than 50 days of operation,the EF was demonstrated to be able to promote the granulation,and the formed An GS enhanced MCFAs yield by 36%.Besides,mechanism analysis indicated that the EF promoted microbial aggregation and extracellular polymeric substances(EPS)synthesis,which enabled An GS to form more easily.Besides,An GS formed with EF improved extracellular electron transfer capacity and microbial function activity,which also contributed to the production of more MCFAs.Overall,this study provides a method to facilitate An GS granulation and revealed the underlying mechanisms,and offers important support for the diverse applications of An GS in other bioresources recovery bioprocesses.展开更多
Particle shape and local breakage significantly affect the deformation characteristics of crushable granular materials.However,in the existing constitutive model research,there is less introduction of particle shape o...Particle shape and local breakage significantly affect the deformation characteristics of crushable granular materials.However,in the existing constitutive model research,there is less introduction of particle shape on particle breakage.A quantitative parameter for the three-dimensional particle shape(Average spherical modulus G_(M))is proposed in this study.Combined with G_(M),the triaxial compression test of granular materials with different particle shapes was carried out,and the particle size distribution before and after the test was determined.The results indicate that the local damage mechanism governs the macroscopic deformation behavior of granular materials,as influenced by the particle gradation of the samples before and after the triaxial compression test.Based on these findings,a binary medium model with a friction element weakening factor is proposed.This model incorporates the effects of particle shape and breakage behavior,significantly enhancing its calculation accuracy.Experimental results demonstrate that the model effectively predicts the deformation of crushable granular materials,accounting for particle shape.展开更多
This work established a quantitative method to access the shear stability of aerobic granular sludge(AGS)and validated its feasibility by using the mature AGS from a pilot-scale(50 tons/day)membrane bioreactor(MBR)for...This work established a quantitative method to access the shear stability of aerobic granular sludge(AGS)and validated its feasibility by using the mature AGS from a pilot-scale(50 tons/day)membrane bioreactor(MBR)for treating real municipal wastewater.The results showed that the changing rate( S)of the peak area(S)of granule size distribution(GSD)exhibited an exponential relationship(R^(2)≥0.76)with the shear time(y=a−b·c^(x)),which was a suitable indicative index to reflect the shear stability of different AGS samples.The limiting granule size(LGS)was defined and proposed to characterize the equilibrium size for AGS after being sheared for a period of time,whose value in terms of Dv50 showed high correlation(R^(2)=0.92)with the parameter a.The free Ca^(2+)(28.44-34.21 mg/L)in the influent specifically interacted with polysaccharides(PS)in the granule’s extracellular polymeric substance(EPS)as a nucleation site,thereby inducing the formation of Ca precipitation to enhance its Young’s modulus,while Ca^(2+) primarily interacted with PS in soluble metabolic product(SMP)during the initial granulation process.Furthermore,the Young’s modulus significantly affected the parameter a related to shear stability(R^(2)=0.99).Since the parameter a was more closely related(R^(2)=1.00)to S than that of the parameter b or c,the excellent correlation(R^(2)=0.99)between the parameter a and the wet density further verified the feasibility of this method.展开更多
Using traditional particle tracking velocimetry based on optical flow for measuring areas with large velocity gradient changes may cause oversmoothing,resulting in significant measurement errors.To address this proble...Using traditional particle tracking velocimetry based on optical flow for measuring areas with large velocity gradient changes may cause oversmoothing,resulting in significant measurement errors.To address this problem,the traditional particle tracking velocimetry method based on an optical flow was improved.The level set segmentation algorithm was used to obtain the boundary contour of the region with large velocity gradient changes,and the non-uniform flow field was divided into regions according to the boundary contour to obtain sub-regions with uniform velocity distribution.The particle tracking velocimetry method based on optical flow was used to measure the granular flow velocity in each sub-region,thus avoiding the problem of granular flow distribution.The simulation results show that the measurement accuracy of this method is approximately 10%higher than that of traditional methods.The method was applied to a velocity measurement experiment on dense granular flow in silos,and the velocity distribution of the granular flow was obtained,verifying the practicality of the method in granular flow fields.展开更多
Coriolis effects,encompassing the dilative,compressive,and deflective manifestations,constitute pivotal considerations in the centrifugal modelling of high-speed granular run-out processes.Notably,under the deflective...Coriolis effects,encompassing the dilative,compressive,and deflective manifestations,constitute pivotal considerations in the centrifugal modelling of high-speed granular run-out processes.Notably,under the deflective Coriolis condition,the velocity component parallel to the rotational axis exerts no influence on the magnitude of Coriolis acceleration.This circumstance implies a potential mitigation of the Coriolis force's deflective impact.Regrettably,extant investigations predominantly emphasize the dilative and compressive Coriolis effects,largely neglecting the pragmatic import of the deflective Coriolis condition.In pursuit of this gap,a series of discrete element method(DEM)simulations have been conducted to scrutinize the feasibility of centrifugal modelling for dry granular run-out processes under deflective Coriolis conditions.The findings concerning the deflective Coriolis effect reveal a consistent rise in the run-out distance by 2%–16%,a modest increase in bulk flow velocity of under 4%,and a slight elevation in average flow depth by no more than 25%.These alterations display smaller dependence on the specific testing conditions due to the granular flow undergoing dual deflections in opposing directions.This underscores the significance and utility of the deflective Coriolis condition.Notably,the anticipated reduction in error in predicting the final run-out distance is substantial,potentially reaching a 150%improvement compared to predictions made under the dilative and compressive Coriolis conditions.Therefore,the deflective Coriolis condition is advised when the final run-out distance of the granular flow is the main concern.To mitigate the impact of Coriolis acceleration,a greater initial height of the granular column is recommended,with a height/width ratio exceeding 1,as the basal friction of the granular material plays a crucial role in mitigating the deflective Coriolis effect.For more transverse-uniform flow properties,the width of the granular column should be as large as possible.展开更多
[Objectives]To explore the mechanism of action of Tongxieyaofang ultrafine granular powder in treating visceral hypersensitivity in rats with diarrhea-predominant irritable bowel syndrome(IBS-D)based on enteric glial ...[Objectives]To explore the mechanism of action of Tongxieyaofang ultrafine granular powder in treating visceral hypersensitivity in rats with diarrhea-predominant irritable bowel syndrome(IBS-D)based on enteric glial cells(EGCs).[Methods]Eighty-four healthy male Wistar rats of SPF grade were selected and randomly assigned to seven groups,each comprising 12 rats:a normal control group,a model control group,a traditional Tongxieyaofang granular powder group(4.060 g/kg),three Tongxieyaofang ultrafine granular powder groups at low,medium,and high doses(1.015,2.030,and 4.060 g/kg of raw drug,respectively),and a pinaverium bromide group(0.018 g/kg).With the exception of the normal control group,all other groups were subjected to an IBS-D visceral hypersensitivity sensitivity model in rats developed by the chronic water avoidance stress method.Three days post modeling,the rats received continuous oral gavage administration for 8 d.Following the treatment period,serum and colon tissue samples were collected from each group.The BDNF level in the serum was quantified using ELISA.Additionally,the protein expression levels of GFAP,BDNF,and TrkB in colon tissues were assessed via Western blot assay.[Results]Compared to the normal control group,the serum BDNF levels in the model control group were significantly elevated(P<0.01).In contrast,each treatment group exhibited a significant reduction in serum BDNF levels relative to the model control group(P<0.01).Furthermore,the protein expression levels of GFAP,BDNF,and TrkB in colon tissue were significantly higher in the model control group compared to the normal control group(P<0.05,P<0.01).Conversely,these protein expressions were significantly decreased in each treatment group compared to the model control group(P<0.05,P<0.01).[Conclusions]Tongxieyaofang ultrafine granular powder effectively alleviates visceral sensitivity in IBS-D rats and inhibits the activation of EGCs,speculating that its mechanism of action involves the suppression of abnormal EGC activation.展开更多
文摘Flood disasters can have a serious impact on people's production and lives, and can cause hugelosses in lives and property security. Based on multi-source remote sensing data, this study establisheddecision tree classification rules through multi-source and multi-temporal feature fusion, classified groundobjects before the disaster and extracted flood information in the disaster area based on optical imagesduring the disaster, so as to achieve rapid acquisition of the disaster situation of each disaster bearing object.In the case of Qianliang Lake, which suffered from flooding in 2020, the results show that decision treeclassification algorithms based on multi-temporal features can effectively integrate multi-temporal and multispectralinformation to overcome the shortcomings of single-temporal image classification and achieveground-truth object classification.
基金supported by the Natural Science Foundation of China[grant number 42071453]the geological hazard investigation project of Liaoning Province[grant number 2022020700179]the Fund of National Key Laboratory of Science and Technology on Remote Sensing Information and imagery Analysis,Beijing Research Institute of Uranium Geology[grant number 6142A01210407].
文摘In this paper,the Multi-Temporal Interferometric Synthetic Aperture Radar(MT-InSAR)technology is adopted to monitor the Line of Sight(LOS)displacement of Fushun West Opencast Coal Mine(FWOCM)and its surrounding areas in northeast China using Sentinel-1 Synthetic Aperture Radar(SAR)images acquired from 2018 to 2022.The spatial-temporal evolution of urban subsidence and the south-slope landslide are both analyzed in detail.Comparison with ground measurements and cross-correlation analysis via cross wavelet transform with monthly precipitation data are also conducted,to analyze the influence factors of displacements in FWOCM.The monitoring results show that a subsidence basin appeared in the urban area near the eastern part of the north slope in 2018,with settlement center located at the intersection of E3000 and fault F1.The Qian Tai Shan(QTS)landslide on the south slope,which experienced rapid sliding during 2014 to 2016,presents seasonal deceleration and acceleration with precipitation,with the maximum displacement in vicinity of the Liushan paleochannel.The results of this paper have fully taken in account for the complications of large topographic relief,geological conditions,spatial distribution and temporal evolution characteristics of surface displacements in opencast mining area.The wide range and long time series dynamic monitoring of opencast mine are of great significance to ensure mine safety production and geological disaster prevention in the investigated mining area.
文摘Creation of a spectral signature reflectance data, which aids in the identification of the crops is important in determining size and location crop fields. Therefore, we developed a spectral signature reflectance for the vegetative stage of the green gram (Vigna. radiata L.) over 5 years (2020, 2018, 2017, 2015, and 2013) for agroecological zone IV and V in Kenya. The years chosen were those whose satellite resolution data was available for the vegetative stage of crop growth in the short rain season (October, November, December (OND)). We used Landsat 8 OLI satellite imagery in this study. Cropping pattern data for the study area were evaluated by calculating the Top of Atmosphere reflectance. Farms geo-referencing, along with field data collection, was undertaken to extract Top of Atmosphere reflectance for bands 2, 3, 4 and 7. We also carried a spectral similarity assessment on the various cropping patterns. The spectral reflectance ranged from 0.07696 - 0.09632, 0.07466 - 0.09467, 0.0704047 - 0.12188,0.19822 - 0.24387, 0.19269 - 0.26900, and 0.11354 - 0.20815 for bands 2, 3, 4, 5, 6, and 7 for green gram, respectively. The results showed a dissimilarity among the various cropping patterns. The lowest dissimilarity index was 0.027 for the maize (Zea mays L.) bean (Phaseolus vulgaris) versus the maize-pigeon pea (Cajanus cajan) crop, while the highest dissimilarity index was 0.443 for the maize bean versus the maize bean and cowpea cropping patterns. High crop dissimilarities experienced across the cropping pattern through these spectral reflectance values confirm that the green gram was potentially identifiable. The results can be used in crop type identification in agroecological lower midland zone IV and V for mung bean management. This study therefore suggests that use of reflectance data in remote sensing of agricultural ecosystems would aid in planning, management, and crop allocation to different ecozones.
基金supported by the Guangdong Special Support ProgramProject(No.2021JC060580)the Foshan Innovation Team Project(No.2130218003140).
文摘In this study,the effects of different salinity gradients and addition of compatible solutes on anaerobic treated effluent water qualities,sludge characteristics and microbial communities were investigated.The increase in salinity resulted in a decrease in particle size of the granular sludge,which was concentrated in the range of 0.5-1.0 mm.The content of EPS(extracellular polymeric substances)in the granular sludge gradually increased with increasing salinity and the addition of betaine(a typical compatible solute).Meanwhile,the microbial community structure was significantly affected by salinity,with high salinity reducing the diversity of bacteria.At higher salinity,Patescibacteria and Proteobacteria gradually became the dominant phylum,with relative abundance increasing to 13.53%and 12.16%at 20 g/L salinity.Desulfobacterota and its subordinate Desulfovibrio,which secrete EPS in large quantities,dominated significantly after betaine addition.Their relative abundance reached 13.65%and 7.86%at phylum level and genus level.The effect of these changes on the treated effluent was shown as the average chemical oxygen demand(COD)removal rate decreased from 82.10%to 79.71%,78.01%,68.51%and 64.55%when the salinity gradually increased from 2 g/L to 6,10,16 and 20 g/L.At the salinity of 20 g/L,average COD removal increased to 71.65%by the addition of 2 mmol/L betaine.The gradient elevated salinity and the exogenous addition of betaine played an important role in achieving stability of the anaerobic system in a highly saline environment,which provided a feasible strategy for anaerobic treatment of organic saline wastewater.
文摘Objective To investigate whether 2,3,5,4'-tetrahydroxystilbene-2-O-β-glucoside(TSG)ameliorated polycystic ovary syndrome(PCOS)-like characteristics by inhibiting inflammation.Methods PCOS models were established by injecting subcutaneously with dehydroepiandrosterone into female Sprague-Dawley rats,followed by receiving intraperitoneal injection of TSG.The granular cells(GCs)KGN were transfected with small interfering RNAs(si-NC and si-CYP19A1).The cells were preincubated with lipopolysaccharide(LPS)and then treated with or without TSG.The estrous cycle was monitored using vaginal exfoliated cells.The morphology of ovarian follicles was analyzed by H&E staining.ELISA was used to analyze estradiol(E2),testosterone(T),follicle stimulating hormone(FSH),luteinizing hormone(LH),IL-6,TNF-α,AGEs,CRP and Omentin-1 levels in serum.Immunohistochemistry was performed to analyze PCNA and CYP19A1 expressions in the GCs of ovaries.Tunel staining was executed to detect the apoptosis of GCs.Quantitative polymerase chain reaction(qPCR)and Western blot were implemented to measure the expression of CYP19A1 in the ovaries and transfected cells.qPCR was used to analyze the expression of IL-6 and TNF-αin the transfected cells treated with LPS and TSG.Results The estrous cycles were restored in TSG group.Compared with model group,the sinus follicles were reduced and corpus luteums were increased in TSG group.TSG group showed increased E2,and decreased T and LH,compared with model group.Pro-inflammatory factors(IL-6,TNF-α,CRP and AGEs)were decreased,and anti-inflammatory factor(Omentin-1)was increased in TSG group compared with those in model group.TSG could partially inhibit decrease of PNCA-positive GCs and increase of Tunel-positive GCs caused by PCOS.The CYP19A1 expression of GCs in TSG group was upregulated compared with model group.The expressions of IL-6 and TNFαin si-CYP19A1 cells were increased compared with si-NC cells.Compared with cells(si-NC and si-CYP19A1)treated without LPS,the expressions of IL-6 and TNF-αcells were increased,and the expression of CYP19A1 was downregulated in LPS-preincubated cells.Compared with cells treated with LPS,the expression of IL-6 and TNF-αwere decreased,and the expression of CYP19A1 was increased in cells treated with LPS and TSG.Compared with si-NC cells treated with LPS and TSG,the expressions of IL-6 and TNF-αcells were increased in the si-CYP19A1 cells treated with LPS and TSG.Conclusion TSG could alleviate PCOS-like characteristics by increasing the expression of CYP19A1 in GCs to inhibit inflammatory response.
文摘The two universes multi-granularity fuzzy rough set model is an effective tool for handling uncertainty problems between two domains with the help of binary fuzzy relations. This article applies the idea of neighborhood rough sets to two universes multi-granularity fuzzy rough sets, and discusses the two-universes multi-granularity neighborhood fuzzy rough set model. Firstly, the upper and lower approximation operators are defined in the two universes multi-granularity neighborhood fuzzy rough set model. Secondly, the properties of the upper and lower approximation operators are discussed. Finally, the properties of the two universes multi-granularity neighborhood fuzzy rough set model are verified through case studies.
文摘The pandemic SARS-CoV-2 has become an undying virus to spread a sustainable disease named COVID-19 for upcoming few years.Mortality rates are rising rapidly as approved drugs are not yet available.Isolation from the infected person or community is the preferred choice to protect our health.Since humans are the only carriers,it might be possible to control the positive rate if the infected population or host carriers are isolated from each other.Isolation alone may not be a proper solution.These are the resolutions of previous research work carried out on COVID-19 throughout the world.The present scenario of the world and public health is knocking hard with a big question of critical uncertainty of COVID-19 because of its imprecise database as per daily positive cases recorded all over the world and in India as well.In this research work,we have pre-sented an optimal control model for COVID-19 using granular differentiability based on fuzzy dynamical systems.In the first step,we created a fuzzy Susceptible-Exposed-Infected-Asymptomatic-Hospitalized-Recovered-Death(SEIAHRD)model for COVID-19,analyzed it using granular differentiability,and reported disease dynamics for time-independent disease control parameters.In the second step,we upgraded the fuzzy dynamical system and granular differentiability model related to time-dependent disease control parameters as an optimal control problem invader.Theoretical studies have been validated with some practical data from the epidemic COVID-19 related to the Indian perspective during first wave and early second wave.
文摘When a vehicle moves over a flexible pavement structure,it generates loading and unloading cycles that produce recoverable(resilient)and permanent(plastic)deformations in the granular base and subbase layers,which are made of unbound granular materials(UGMs).The primary parameter used to evaluate the resilient response of UGMs in pavements is the resilient modulus(MR).The MR is widely used in calculating stress-strain states for flexible pavement design and as a control parameter during the construction process.It is also employed to understand the progression of distresses,such as fatigue cracking and rutting.The main objective of this study was to conduct a literature review on the resilient behavior of UGMs.This manuscript presents and describes the MR and the factors that influence it.It also outlines the evolution of the mathematical equations most commonly used to estimate and predict this physical parameter.Conclusions and recommendations for future research are provided at the end of the article.Despite the large amount of research done on the subject,the resilient behavior of UGM has not yet been fully understood.This is since these materials are highly heterogeneous and show nonlinear-anisotropic behavior under different cyclic loading paths and water contents.Likewise,these materials undergo different behaviors depending on their macro and microscopic properties(gradation,density,porosity,texture,mineralogy,particle geometry and orientation,temperature,among others).On the other hand,the main limitation of the mathematical equations is that their parameters are difficult to determine experimentally and are not constants of the material(they are state variables that can change with multiple factors).Additionally,these equations do not consider the boundary conditions to which UGM in pavements are exposed.Moreover,they are obtained from repeated load triaxial(RLT)tests,which cannot simulate the three cyclic stress components(vertical,horizontal,and shear)to which UGMs are subjected in a pavement.In recent years,there has been an increase in studies evaluating the use of recycled aggregates and the effect of temperature(particularly at subzero temperatures),but more research is still needed to reach definitive conclusions.
基金supported by the National Natural Science Foundation of China(Grant Nos.52378321 and 52079003).
文摘Based on the energy dissipation caused by consolidation deformation of the porous media under external force and migration of the internal suspended substances,a coupled multiphase-substance flow(CMF)model was established.This model introduced the new concepts,such as particle temperature and particle entropy,to describe energy dissipation at meso-level.This model used a potential energy density function and migration coefficients to establish the corresponding connection between the dissipative force and dissipative flow.This viewpoint unifies the deformation,seepage,and suspended substance migration of geotechnical materials under the framework of granular thermodynamics.It can reflect the evolution of effective stress in the solid matrix of multi-components in a particle-reorganized state,and considers the temperature driving effect.The proposed CMF model is validated using the experimental results under coupled migration of heavy metal ions(HMs)and suspended particles(SPs).The calculation results demonstrated that the CMF model can describe the flow process under the conditions of arbitrary changes in different suspended substance types,injection concentrations,and injection velocities.
基金funded by the Ministry of Education of the Russian Federation within the framework of a state assignment,number 1023032300071-6-2.3.1.
文摘The dynamics of fluid and non-buoyant particles in a librating horizontal annulus is studied experimentally.In the absence of librations,the granular material forms a cylindrical layer near the outer boundary of the annulus and undergoes rigid-body rotation with the fluid and the annulus.It is demonstrated that the librational liquefaction of the granular material results in pattern formation.This self-organization process stems from the excitation of inertial modes induced by the oscillatory motion of liquefied granular material under the influence of the gravitational force.The inertial wave induces vortical fluid flow which entrains particles from rest and forms eroded areas that are equidistant from each other along the axis of rotation.Theoretical analysis and experiments demonstrate that a liquefied layer of granular material oscillates with a radian frequency equal to the angular velocity of the annulus and interacts with the inertial wave it excites.The new phenomenon of libration-induced pattern formation is of practical interest as it can be used to control multiphase flows and mass transfer in rotating containers in a variety of industrial processes.
基金funded by the National Natural Science Foundation of China(Grant Nos.42207227)the Natural Science Foundation of Hunan Province,China(Grant No.2022JJ40586)The authors also thank the China Postdoctoral Science Foundation(Grant Nos.2022M722428).
文摘In the deep geological disposal repository of high-level radioactive waste,buffer/backfill materials typically consist of compacted bentonite block and granular bentonite.As these materials undergo a long-term hydration,it is anticipated that the two forms of bentonite materials(i.e.compacted bentonite powder(CBP)and granular bentonite(GB))are expected to exhibit differing hydro-mechanical behaviors due to the differences in their structures.This work aims to investigate the differences in swelling pressure and compressibility through a series of swelling pressure tests,compression tests and mercury intrusion porosimetry(MIP)tests.The experimental results demonstrated that swelling pressure curves of the CBP specimens showed higher first peak values and more pronounced collapse than those of the GB specimens at a given dry density,regardless of vapor-water hydration or liquid-water hydration.The final swelling pressures of the two materials were similar at the same dry density,suggesting an independent correlation between swelling pressure and dry density.At the high suction range,the compression curves exhibited an obvious bi-linear pattern for the CBP specimens and a significant nonlinearity for the GB specimens.Meanwhile,the CBP specimens presented higher pre-consolidation pressures and larger compression indices than the GB specimens at a given suction.As suction decreased,the compression curves of the two materials gradually approached each other and their differences were reduced accordingly.After reaching saturation,a good consistency between them was observed whether for final swelling pressure or compressibility.Pore structure analysis revealed that the two materials both presented an initially double structure,and their differences were primarily manifested at the macrostructural level.Eventually,the differences in swelling pressure or compression curves of the two materials were well interpreted by combining microstructural evolutions.
基金supported by the National Natural Science Foundation of China(Grant numbers 41977233)。
文摘Bridge pier failures from granular flow impacts are common.Installing defense piles upstream is an effective mitigation strategy,yet their protective mechanisms and standardized design guidelines are unclear.This study employed 3D discrete element method to analyze the influence of defense pile size and placement on its performance across 219 scenarios,providing a detailed examination of their protective mechanisms.Results show that optimizing these factors can reduce the maximum impact force on bridge piers by up to 94%.In terms of size,a critical height threshold is identified,beyond which increasing pile height does not enhance protection.This threshold depends on the movement height of granular particles at the slope base.Protection effectiveness varies with pile size:when H≤0.05 h(H is the height of defense piles,h is the height of bridge),protection marginally improves with increasing height and diameter;for 0.05 h<H<0.15 h,protection strongly correlates with both parameters;for H≥0.15 h,diameter becomes the dominant factor.In terms of placement,an optimal longitudinal distance exists between the defense pile and the bridge pier.The larger the diameter,the greater the optimal longitudinal distance.However,the transverse distance is inversely related to protection effectiveness.Mechanistic analysis shows that defense piles are more effective at redirecting particles to prevent direct collisions with the pier(contributing 100%impact energy reduction before the non-dimensional travel time t*=7.01 and 63%–100%afterward)than at reducing particle velocity.This study provides insights into the protective mechanisms of defense piles and informs strategies for optimizing bridge pier protection in granular flow-prone regions.
基金support from the National Natural Science Foundation of China(Nos.U21A20394 and 52305314)the Beijing Natural Science Foundation(Nos.7252285 and L246001)the National Key Research and Development Program of China(No.2023YFB4605800)。
文摘Granular composite(GC)hydrogels have attracted considerable interest in biomedical applications due to their versatile printability and exceptional mechanical properties.However,the lack of comprehensive design guidelines has limited their optimal engineering,as the factors influencing their mechanical performance and printability remain largely unexamined.In this study,we developed GC hydrogels by integrating microgels with interstitial matrices of photocrosslinkable gelatin methacrylate(GelMA).We utilized confocal microscopy and nanoindentation analyses to investigate the spatial distribution and mechanical behavior of these hydrogels.Our findings indicate that the mechanical and rheological properties of GC hydrogels can be precisely tailored by adjusting the volume fraction and size of the microgels.Furthermore,hydrogen bonds were identified as significant contributors to compressive performance,although they had minimal effect on cyclic mechanical behavior.Compared to bulk GelMA hydrogels,GC hydrogels demonstrated enhanced printability and remarkable superelasticity.As a proof of concept,we illustrated their dual printability in embedded printing to create prosthetic liver models for preoperative planning.This study provides valuable insights into the design and optimization of GC hydrogels for advanced biomedical applications.
基金supported by the National Key Research and Development Programme of China(No.2023YFC3206903)the Natural Science Foundation of China(No.51938010)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX23_1717).
文摘Red anaerobic ammonia oxidation (Anammox) granular sludge (AnGS) has been reported insuccessfully operating Anammox systems, and its color is associated with sludge activity.However, in long-term operating systems, AnGS exhibits different sensory colors, physicalstructures, community structures, and denitrification performance, but the relationship betweenthem has not yet been elucidated.The AnGS of the Anammox system, which has beenin operation for more than a decade, can be divided into twomain categories: red and white.The specific Anammox activity (SAA) in conventional red AnGS increased continuously asthe particle size increased from <0.51 mm to 6.02 ± 0.84 mm. The SAA of white AnGS wereslightly lower than those of red AnGS with similarly-size granules but significantly higherthan AnGS with smaller red granules. Compared with red AnGS, the extracellular polymericsubstances of white AnGS were significantly reduced,mainly due to the higher intracellulariron content, resulting in lower heme c concentration. Thus, heme c may prove not to bean evaluative tool for measuring Anammox activity. Red and white AnGS, whether throughself-aggregation or adsorption by hydroxyl apatite and other carriers, will face the fate ofinternal voids during particle size growth. White AnGS exhibited amore complex microbialcommunity than red AnGS. Candidatus Brocadia was abundant in red AnGS and the abundanceincreased with increasing granule size. Candidatus Kuenenia and Candidatus Jetteniamade significant contributions to denitrification in white AnGS. This study provides a newperspective on particle selection for anammox engineering applications.
基金supported by the Natural Science Foundation of Heilongjiang Province(No.LH2023E051)Open Project of State Key Laboratory of Urban Water Resource and Environment(No.HC202241)Young Scientist Studio of Harbin Institute of Technology。
文摘Granular sludges can resist the toxicity inhibition of medium-chain fatty acids(MCFAs)and enhance the chain elongation(CE)process.However,the granulation process is time-consuming and requires a suitable facilitating granulation mean.This study proposed two continuous fed Expanded Granular Sludge Bed bioreactors,one with electric field(EF)and one without,to demonstrate the promotion of sludge granulation by EF and the enhancement of MCFAs production efficiency by the anaerobic granular sludge(An GS).Through more than 50 days of operation,the EF was demonstrated to be able to promote the granulation,and the formed An GS enhanced MCFAs yield by 36%.Besides,mechanism analysis indicated that the EF promoted microbial aggregation and extracellular polymeric substances(EPS)synthesis,which enabled An GS to form more easily.Besides,An GS formed with EF improved extracellular electron transfer capacity and microbial function activity,which also contributed to the production of more MCFAs.Overall,this study provides a method to facilitate An GS granulation and revealed the underlying mechanisms,and offers important support for the diverse applications of An GS in other bioresources recovery bioprocesses.
基金the National Natural Science Foundation of China(Grant No.12372376)the Scientific Innovation Practice Project of Postgraduates of Chang’an University(300103724017)。
文摘Particle shape and local breakage significantly affect the deformation characteristics of crushable granular materials.However,in the existing constitutive model research,there is less introduction of particle shape on particle breakage.A quantitative parameter for the three-dimensional particle shape(Average spherical modulus G_(M))is proposed in this study.Combined with G_(M),the triaxial compression test of granular materials with different particle shapes was carried out,and the particle size distribution before and after the test was determined.The results indicate that the local damage mechanism governs the macroscopic deformation behavior of granular materials,as influenced by the particle gradation of the samples before and after the triaxial compression test.Based on these findings,a binary medium model with a friction element weakening factor is proposed.This model incorporates the effects of particle shape and breakage behavior,significantly enhancing its calculation accuracy.Experimental results demonstrate that the model effectively predicts the deformation of crushable granular materials,accounting for particle shape.
基金supported by the Key Technologies Research and Development Program of Guangzhou (No.2023B03J1284)Guangdong Yuehai Water Investment Co.,Ltd. (No.CC80-QT01-2020-0010).
文摘This work established a quantitative method to access the shear stability of aerobic granular sludge(AGS)and validated its feasibility by using the mature AGS from a pilot-scale(50 tons/day)membrane bioreactor(MBR)for treating real municipal wastewater.The results showed that the changing rate( S)of the peak area(S)of granule size distribution(GSD)exhibited an exponential relationship(R^(2)≥0.76)with the shear time(y=a−b·c^(x)),which was a suitable indicative index to reflect the shear stability of different AGS samples.The limiting granule size(LGS)was defined and proposed to characterize the equilibrium size for AGS after being sheared for a period of time,whose value in terms of Dv50 showed high correlation(R^(2)=0.92)with the parameter a.The free Ca^(2+)(28.44-34.21 mg/L)in the influent specifically interacted with polysaccharides(PS)in the granule’s extracellular polymeric substance(EPS)as a nucleation site,thereby inducing the formation of Ca precipitation to enhance its Young’s modulus,while Ca^(2+) primarily interacted with PS in soluble metabolic product(SMP)during the initial granulation process.Furthermore,the Young’s modulus significantly affected the parameter a related to shear stability(R^(2)=0.99).Since the parameter a was more closely related(R^(2)=1.00)to S than that of the parameter b or c,the excellent correlation(R^(2)=0.99)between the parameter a and the wet density further verified the feasibility of this method.
文摘Using traditional particle tracking velocimetry based on optical flow for measuring areas with large velocity gradient changes may cause oversmoothing,resulting in significant measurement errors.To address this problem,the traditional particle tracking velocimetry method based on an optical flow was improved.The level set segmentation algorithm was used to obtain the boundary contour of the region with large velocity gradient changes,and the non-uniform flow field was divided into regions according to the boundary contour to obtain sub-regions with uniform velocity distribution.The particle tracking velocimetry method based on optical flow was used to measure the granular flow velocity in each sub-region,thus avoiding the problem of granular flow distribution.The simulation results show that the measurement accuracy of this method is approximately 10%higher than that of traditional methods.The method was applied to a velocity measurement experiment on dense granular flow in silos,and the velocity distribution of the granular flow was obtained,verifying the practicality of the method in granular flow fields.
基金supported by the National Natural Science Foundation of China(Grant Nos.42120104008 and 42307214)the Postdoctoral Fellowship Program of CPSF(Grant No.GZB20230620).
文摘Coriolis effects,encompassing the dilative,compressive,and deflective manifestations,constitute pivotal considerations in the centrifugal modelling of high-speed granular run-out processes.Notably,under the deflective Coriolis condition,the velocity component parallel to the rotational axis exerts no influence on the magnitude of Coriolis acceleration.This circumstance implies a potential mitigation of the Coriolis force's deflective impact.Regrettably,extant investigations predominantly emphasize the dilative and compressive Coriolis effects,largely neglecting the pragmatic import of the deflective Coriolis condition.In pursuit of this gap,a series of discrete element method(DEM)simulations have been conducted to scrutinize the feasibility of centrifugal modelling for dry granular run-out processes under deflective Coriolis conditions.The findings concerning the deflective Coriolis effect reveal a consistent rise in the run-out distance by 2%–16%,a modest increase in bulk flow velocity of under 4%,and a slight elevation in average flow depth by no more than 25%.These alterations display smaller dependence on the specific testing conditions due to the granular flow undergoing dual deflections in opposing directions.This underscores the significance and utility of the deflective Coriolis condition.Notably,the anticipated reduction in error in predicting the final run-out distance is substantial,potentially reaching a 150%improvement compared to predictions made under the dilative and compressive Coriolis conditions.Therefore,the deflective Coriolis condition is advised when the final run-out distance of the granular flow is the main concern.To mitigate the impact of Coriolis acceleration,a greater initial height of the granular column is recommended,with a height/width ratio exceeding 1,as the basal friction of the granular material plays a crucial role in mitigating the deflective Coriolis effect.For more transverse-uniform flow properties,the width of the granular column should be as large as possible.
基金Supported by Science and Technology Plan Project of Zhongshan City(2022B1126).
文摘[Objectives]To explore the mechanism of action of Tongxieyaofang ultrafine granular powder in treating visceral hypersensitivity in rats with diarrhea-predominant irritable bowel syndrome(IBS-D)based on enteric glial cells(EGCs).[Methods]Eighty-four healthy male Wistar rats of SPF grade were selected and randomly assigned to seven groups,each comprising 12 rats:a normal control group,a model control group,a traditional Tongxieyaofang granular powder group(4.060 g/kg),three Tongxieyaofang ultrafine granular powder groups at low,medium,and high doses(1.015,2.030,and 4.060 g/kg of raw drug,respectively),and a pinaverium bromide group(0.018 g/kg).With the exception of the normal control group,all other groups were subjected to an IBS-D visceral hypersensitivity sensitivity model in rats developed by the chronic water avoidance stress method.Three days post modeling,the rats received continuous oral gavage administration for 8 d.Following the treatment period,serum and colon tissue samples were collected from each group.The BDNF level in the serum was quantified using ELISA.Additionally,the protein expression levels of GFAP,BDNF,and TrkB in colon tissues were assessed via Western blot assay.[Results]Compared to the normal control group,the serum BDNF levels in the model control group were significantly elevated(P<0.01).In contrast,each treatment group exhibited a significant reduction in serum BDNF levels relative to the model control group(P<0.01).Furthermore,the protein expression levels of GFAP,BDNF,and TrkB in colon tissue were significantly higher in the model control group compared to the normal control group(P<0.05,P<0.01).Conversely,these protein expressions were significantly decreased in each treatment group compared to the model control group(P<0.05,P<0.01).[Conclusions]Tongxieyaofang ultrafine granular powder effectively alleviates visceral sensitivity in IBS-D rats and inhibits the activation of EGCs,speculating that its mechanism of action involves the suppression of abnormal EGC activation.
