The identification of landslide-prone areas is an essential step in landslide hazard assessment and mitigation of landslide-related losses.In this study,we applied two novel deep learning algorithms,the recurrent neur...The identification of landslide-prone areas is an essential step in landslide hazard assessment and mitigation of landslide-related losses.In this study,we applied two novel deep learning algorithms,the recurrent neural network(RNN)and convolutional neural network(CNN),for national-scale landslide susceptibility mapping of Iran.We prepared a dataset comprising 4069 historical landslide locations and 11 conditioning factors(altitude,slope degree,profile curvature,distance to river,aspect,plan curvature,distance to road,distance to fault,rainfall,geology and land-sue)to construct a geospatial database and divided the data into the training and the testing dataset.We then developed RNN and CNN algorithms to generate landslide susceptibility maps of Iran using the training dataset.We calculated the receiver operating characteristic(ROC)curve and used the area under the curve(AUC)for the quantitative evaluation of the landslide susceptibility maps using the testing dataset.Better performance in both the training and testing phases was provided by the RNN algorithm(AUC=0.88)than by the CNN algorithm(AUC=0.85).Finally,we calculated areas of susceptibility for each province and found that 6%and 14%of the land area of Iran is very highly and highly susceptible to future landslide events,respectively,with the highest susceptibility in Chaharmahal and Bakhtiari Province(33.8%).About 31%of cities of Iran are located in areas with high and very high landslide susceptibility.The results of the present study will be useful for the development of landslide hazard mitigation strategies.展开更多
Diabetic nephropathy accounts for the most serious microvascular complication of diabetes mellitus. It is suggested that the prevalence of diabetic nephropathy will continue to increase in future posing a major challe...Diabetic nephropathy accounts for the most serious microvascular complication of diabetes mellitus. It is suggested that the prevalence of diabetic nephropathy will continue to increase in future posing a major challenge to the healthcare system resulting in increased morbidity and mortality. It occurs as a result of interaction between both genetic and environmental factors in individuals with both type 1 and type 2 diabetes. Genetic susceptibility has been proposed as an important factor for the development and progression of diabetic nephropathy, and various research efforts are being executed worldwide to identify the susceptibility gene for diabetic nephropathy. Numerous single nucleotide polymorphisms have been found in various genes giving rise to various gene variants which have been found to play a major role in genetic susceptibility to diabetic nephropathy. The risk of developing diabetic nephropathy is increased several times by inheriting risk alleles at susceptibility loci of various genes like ACE, IL, TNF-α, COL4A1, e NOS, SOD2, APOE, GLUT, etc. The identification of these genetic variants at a biomarker level could thus, allow the detection of those individuals at high risk for diabetic nephropathy which could thus help in the treatment, diagnosis and early prevention of the disease. The present review discusses about the various gene variants found till date to be associated with diabetic nephropathy.展开更多
Biochar is produced from the pyrolysis of carbon-rich plant- and animal-residues under low oxygen and high temperature conditions and has been increasingly used for its positive role in soil compartmentalization throu...Biochar is produced from the pyrolysis of carbon-rich plant- and animal-residues under low oxygen and high temperature conditions and has been increasingly used for its positive role in soil compartmentalization through activities such as carbon sequestration and improving soil quality. Biochar is also considered a unique adsorbent due to its high specific surface area and highly carbonaceous nature. Therefore, soil amendments with small amounts of biochar could result in higher adsorption and, consequently, decrease the bioavailability of contaminants to microbial communities, plants, earthworms, and other organisms in the soil. However, the mechanisms affecting the environmental fate and behavior of organic contaminants, especially pesticides in biochar-amended soil, are not well understood. The purpose of this work is to review the role of biochar in primary processes, such as adsorption–desorption and leaching of pesticides. Biochar has demonstrable effects on the fate and effects of pesticides and has been shown to affect the degradation and bioavailability of pesticides for living organisms. Moreover, some key aspects of agricultural and environmental applications of biochar are highlighted.展开更多
The microstructure and mechanical properties of Inconel 625 alloy fabricated by wire arc additive manufacturing process were evaluated under as-prepared and heat-treated conditions.A dendritic Ni-based solid solution ...The microstructure and mechanical properties of Inconel 625 alloy fabricated by wire arc additive manufacturing process were evaluated under as-prepared and heat-treated conditions.A dendritic Ni-based solid solution phase along with(Nb,Ti)C carbide,Laves,and δ-Ni3Nb secondary phases were developed in the microstructure of the as-prepared alloy.Solution heat treatment led to the dissolution of Laves and Ni3Nb phases.In addition,dendrites were replaced with large columnar grains.Aging heat treatment resulted in the formation of grain boundary M23C6 carbide and nanometric γ''precipitates.Hardness,yield and tensile strengths,as well as elongation of the as-prepared part,were close to those of the cast alloy and its fracture occurred in a transgranular ductile mode.Solution heat treatment improved hardness and yield strength and declined the elongation,but it did not have a considerable impact on the tensile strength.Furthermore,aging heat treatment caused the tensile properties to deteriorate and changed the fracture to a mixture of transgranular ductile and intergranular brittle mode.展开更多
In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The m...In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The mission aims at determining the equation of state of matter at supra-nuclear density, measuring effects of QED, and understanding the dynamics of matter in strong-field gravity. In addition to investigating fundamental physics, eXTP will be a very powerful observatory for astrophysics that will provide observations of unprecedented quality on a variety of galactic and extragalactic objects. In particular, its wide field monitoring capabilities will be highly instrumental to detect the electro-magnetic counterparts of gravitational wave sources.The paper provides a detailed description of:(1) the technological and technical aspects, and the expected performance of the instruments of the scientific payload;(2) the elements and functions of the mission, from the spacecraft to the ground segment.展开更多
Quartz, the second most abundant mineral in the earth's crust, is a gangue mineral in practically every flotation process. Coarse quartz flotation has been a long standing problem in various mineral processing pla...Quartz, the second most abundant mineral in the earth's crust, is a gangue mineral in practically every flotation process. Coarse quartz flotation has been a long standing problem in various mineral processing plants to reduce milling cost and increase valuable mineral recovery. Based on this, the effects of nanobubbles(NBs) and hydrodynamic parameters on coarse quartz particle flotation were systematically investigated. Mechanical flotation experiments were carried out using the 7 cm and 9 cm diameter impellers in order to produce different hydrodynamic conditions. 900–1300 rpm impeller speeds were used for the 7 cm diameter impeller and 554–786 rpm for the 9 cm diameter impeller. The results show that the presence of NBs increased the flotation recovery of à425 + 106 lm quartz by up to 21%. For the7 cm diameter impeller, the maximum flotation recoveries of 86.4% and 98% were obtained in the absence and presence of NBs at Reynolds number(Re) of 81,000 and 66,000, respectively. For the 9 cm diameter impeller, the maximum recoveries of 86.3% and 97.5% were obtained in the absence and presence of NBs at Re of 90,000 and 75,000, respectively. NBs increased the flotation rate constant up to 36%.展开更多
Technical challenges have always been part of underground mining activities,however,some of these challenges grow in complexity as mining occurs in deeper and deeper settings.One such challenge is rock mass stability ...Technical challenges have always been part of underground mining activities,however,some of these challenges grow in complexity as mining occurs in deeper and deeper settings.One such challenge is rock mass stability and the risk of rockburst events.To overcome these challenges,and to limit the risks and impacts of events such as rockbursts,advanced solutions must be developed and best practices implemented.Rockbursts are common in underground mines and substantially threaten the safety of personnel and equipment,and can cause major disruptions in mine development and operations.Rockbursts consist of violent wall rock failures associated with high energy rock projections in response to the instantaneous stress release in rock mass under high strain conditions.Therefore,it is necessary to develop a good understanding of the conditions and mechanisms leading to a rockburst,and to improve risk assessment methods.The capacity to properly estimate the risks of rockburst occurrence is essential in underground operations.However,a limited number of studies have examined and compared yet different empirical methods of rockburst.The current understanding of this important hazard in the mining industry is summarized in this paper to provide the necessary perspective or tools to best assess the risks of rockburst occurrence in deep mines.The various classifications of rockbursts and their mechanisms are discussed.The paper also reviews the current empirical methods of rockburst prediction,which are mostly dependent on geomechanical parameters of the rock such as uniaxial compressive strength of the rock,as well as its tensile strength and elasticity modulus.At the end of this paper,some current achievements and limitations of empirical methods are discussed.展开更多
Rock joints are often subjected to dynamic loads induced by earthquake and blasting during mining and rock cutting. Hence, cyclic shear load can be induced along the joints and it is important to evaluate the shear be...Rock joints are often subjected to dynamic loads induced by earthquake and blasting during mining and rock cutting. Hence, cyclic shear load can be induced along the joints and it is important to evaluate the shear behavior of rock joint under this condition. In the present study, synthetic rock joints were prepared with plaster of Paris(Po P). Regular joints were simulated by keeping regular asperity with asperity angles of 15°-15° and 30°-30°, and irregular rock joints which are closer to natural joints were replicated by keeping the asperity angles of 15°-30° and 15°-45°. The sample size and amplitude of roughness were kept the same for both regular and irregular joints which were 298 mm×298 mm×125 mm and 5 mm, respectively. Shear test was performed on these joints using a large-scale direct shear testing machine by keeping the frequency and amplitude of shear load under constant cyclic condition with different normal stress values. As expected, the shear strength of rock joints increased with the increases in the asperity angle and normal load during the first cycle of shearing or static load. With the increase of the number of shear cycles, the shear strength decreased for all the asperity angles but the rate of reduction was more in case of high asperity angles. Test results indicated that shear strength of irregular joints was higher than that of regular joints at different cycles of shearing at low normal stress. Shearing and degradation of joint asperities on regular joints were the same between loading and unloading, but different for irregular joints. Shear strength and joint degradation were more significant on the slope of asperity with higher angles on the irregular joint until two angles of asperities became equal during the cycle of shearing and it started behaving like regular joints for subsequent cycles.展开更多
With the rapid growth of power systems measurements in terms of size and complexity,discovering statistical patterns for a large variety of real-world applications such as renewable energy prediction,demand response,e...With the rapid growth of power systems measurements in terms of size and complexity,discovering statistical patterns for a large variety of real-world applications such as renewable energy prediction,demand response,energy disaggregation,and state estimation is considered a crucial challenge.In recent years,deep learning has emerged as a novel class of machine learning algorithms that represents power systems data via a large hypothesis space that leads to the state-of-the-art performance compared to most recent data-driven algorithms.This study explores the theoretical advantages of deep representation learning in power systems research.We review deep learning methodologies presented and applied in a wide range of supervised,unsupervised,and semi-supervised applications as well as reinforcement learning tasks.We discuss various settings of problems solved by discriminative deep models including stacked autoencoders and convolutional neural networks as well as generative deep architectures such as deep belief networks and variational autoencoders.The theoretical and experimental analysis of deep neural networks in this study motivates longterm research on optimizing this cutting-edge class of models to achieve significant improvements in the future power systems research.展开更多
As threats of landslide hazards have become gradually more severe in recent decades,studies on landslide prevention and mitigation have attracted widespread attention in relevant domains.A hot research topic has been ...As threats of landslide hazards have become gradually more severe in recent decades,studies on landslide prevention and mitigation have attracted widespread attention in relevant domains.A hot research topic has been the ability to predict landslide susceptibility,which can be used to design schemes of land exploitation and urban development in mountainous areas.In this study,the teaching-learning-based optimization(TLBO)and satin bowerbird optimizer(SBO)algorithms were applied to optimize the adaptive neuro-fuzzy inference system(ANFIS)model for landslide susceptibility mapping.In the study area,152 landslides were identified and randomly divided into two groups as training(70%)and validation(30%)dataset.Additionally,a total of fifteen landslide influencing factors were selected.The relative importance and weights of various influencing factors were determined using the step-wise weight assessment ratio analysis(SWARA)method.Finally,the comprehensive performance of the two models was validated and compared using various indexes,such as the root mean square error(RMSE),processing time,convergence,and area under receiver operating characteristic curves(AUROC).The results demonstrated that the AUROC values of the ANFIS,ANFIS-TLBO and ANFIS-SBO models with the training data were 0.808,0.785 and 0.755,respectively.In terms of the validation dataset,the ANFISSBO model exhibited a higher AUROC value of 0.781,while the AUROC value of the ANFIS-TLBO and ANFIS models were 0.749 and 0.681,respectively.Moreover,the ANFIS-SBO model showed lower RMSE values for the validation dataset,indicating that the SBO algorithm had a better optimization capability.Meanwhile,the processing time and convergence of the ANFIS-SBO model were far superior to those of the ANFIS-TLBO model.Therefore,both the ensemble models proposed in this paper can generate adequate results,and the ANFIS-SBO model is recommended as the more suitable model for landslide susceptibility assessment in the study area considered due to its excellent accuracy and ef展开更多
As the most abundant biopolymer on the earth,cellulose has recently gained significant attention in the development of antibacterial biomaterials.Biodegradability,renewability,strong mechanical properties,tunable aspe...As the most abundant biopolymer on the earth,cellulose has recently gained significant attention in the development of antibacterial biomaterials.Biodegradability,renewability,strong mechanical properties,tunable aspect ratio,and low density offer tremendous possibilities for the use of cellulose in various fields.Owing to the high number of reactive groups(i.e.,hydroxyl groups)on the cellulose surface,it can be readily functionalized with various functional groups,such as aldehydes,carboxylic acids,and amines,leading to diverse properties.In addition,the ease of surface modification of cellulose expands the range of compounds which can be grafted onto its structure,such as proteins,polymers,metal nanoparticles,and antibiotics.There are many studies in which cellulose nano-/microfibrils and nanocrystals are used as a support for antibacterial agents.However,little is known about the relationship between cellulose chemical surface modification and its antibacterial activity or biocompatibility.In this study,we have summarized various techniques for surface modifications of cellulose nanostructures and its derivatives along with their antibacterial and biocompatibility behavior to develop non-leaching and durable antibacterial materials.Despite the high effectiveness of surface-modified cellulosic antibacterial materials,more studies on their mechanism of action,the relationship between their properties and their effectivity,and more in vivo studies are required.展开更多
The diurnal fluctuation in soil temperature may influence soil organic carbon （SOC） mineralization, but there is no consensus on SOC mineralization response to the cyclical fluctuation in soil temperature. A 56-d in...The diurnal fluctuation in soil temperature may influence soil organic carbon （SOC） mineralization, but there is no consensus on SOC mineralization response to the cyclical fluctuation in soil temperature. A 56-d incubation experiment was conducted to investigate the effects of constant and variable temperatures on SOC mineralization. Three soils were collected from the karst region in western Guizhou Province, southwestern China, including a limestone soil under forest, a limestone soil under crops and a yellow soil under crops. According to the World Reference Base （WRB） classification, the two limestone soils were classified as Haplic Luvisols and the yellow soil as a Dystric Luvisol. These soils were incubated at three constant temperatures （15, 20 and 25 ℃） and cyclically fluctuating temperatures （diurnal cycle between 15 and 25 ℃）. The results showed that the 56-d cumulative SOC mineralized （C56） at the fluctuating temperatures was between those at constant 15 and 25 ℃, suggesting that the cumulative SOC mineralization was restricted by temperature range. The SOC mineralization responses to the fluctuating temperatures were different among the three soils, especially in contrast to those at constant 20 ~C. Compared with constant 20 ℃, significant （P 〈 0.05） decreases and increases in C56 value were found in the limestone soil under forest and yellow soil under crops at the fluctuating temperatures, respectively. At the fluctuating temperatures, the forest soil with lower temperature coefficient Q10 （the relative change in SOC mineralization rate as a result of increasing the temperature by 10 ℃） had a significantly （P 〈 0.05） lower SOC mineralization intensity than the two cropland soils. These indicated that differences in temperature pattern （constant or fluctuating） could significantly influence SOC mineralization, and SOC mineralization responses to the fluctuating temperatures might be affected by soil characteristics. Moreover, the warmer temperatures 展开更多
Friction and wear phenomena encountered in mechanical systems with moving components are directly related to efficiency,reliability and life of the system.Hence,minimizing and controlling these phenomena to achieve th...Friction and wear phenomena encountered in mechanical systems with moving components are directly related to efficiency,reliability and life of the system.Hence,minimizing and controlling these phenomena to achieve the desired system performance is crucial.Among the numerous strategies developed for reducing friction and wear,coatings have been successfully utilized in various engineering applications to mitigate tribological problems.One of the benefits of coatings is that they may be fabricated using a variety of materials in several different forms and structures to satisfy the requirements of the operating conditions.Among many types,coatings that are comprised of a combination of materials in the form of a multilayer have been gaining much interest due to the added degree of freedom in tailoring the coating property.In this paper,the properties and development status of multilayer coating systems for tribological applications were reviewed with the aim to gain a better understanding regarding their advantages and limitations.Specifically,focus was given to Ti-based and Cr-based coatings since Ti and Cr were identified as important elements in multilayer coating applications.Emphasis was given to materials,design concepts,mechanical properties,deposition method,and friction and wear characteristics of these types of coatings.展开更多
Seismic ground faulting is the greatest hazard for continuous buried pipelines.Over the years,researchers have attempted to understand pipeline behavior mostly via numerical modeling such as the finite element method....Seismic ground faulting is the greatest hazard for continuous buried pipelines.Over the years,researchers have attempted to understand pipeline behavior mostly via numerical modeling such as the finite element method.The lack of well-documented field case histories of pipeline failure from seismic ground faulting and the cost and complicated facilities needed for full-scale experimental simulation mean that a centrifuge-based method to determine the behavior of pipelines subjected to faulting is best to verify numerical approaches.This paper presents results from three centrifuge tests designed to investigate continuous buried steel pipeline behavior subjected to normal faulting.The experimental setup and procedure are described and the recorded axial and bending strains induced in a pipeline are presented and compared to those obtained via analytical methods.The influence of factors such as faulting offset,burial depth and pipe diameter on the axial and bending strains of pipes and on ground soil failure and pipeline deformation patterns are also investigated.Finally,the tensile rupture of a pipeline due to normal faulting is investigated.展开更多
The dissimilar joining of biodegradable magnesium alloy to pure commercial titanium by rotational friction welding with rotational speeds of 1100,1200 and 1300 r/min for the production of bio-screw was investigated.Th...The dissimilar joining of biodegradable magnesium alloy to pure commercial titanium by rotational friction welding with rotational speeds of 1100,1200 and 1300 r/min for the production of bio-screw was investigated.The metallographic analysis revealed that a good joining was obtained at the Ti/Mg alloy joint.On the magnesium alloy side,various regions such as the weld center zone(WCZ),dynamic recrystallization zone(DRX),thermo-mechanically affected zone(TMAZ)and partially deformed zone(PDZ)were observed.The highest tensile and shear strengths were 173 and 103.2 MPa,respectively at a rotational speed of 1300 r/min.The Ti/Mg alloy dissimilar friction welded joint failed at the vicinity of the intermetallic zone containing Ti3Al phase.The hardness values from the base metal magnesium alloy to the joining point increased mainly due to grain refinement(8.57μm in diameter)and the presence of titanium particles,while the hardness values were constant on the titanium side.It was also found that the corrosion rate of the Ti/Mg alloy joint was higher compared with that of the Ti and Mg alloy from the immersion studies.Additionally,the sample with a rotational speed of 1300 r/min showed better biocompatibility and a cell viability of 98.12%due to better corrosion resistance.展开更多
Cross-linked poly（diallyldimethylammonium chloride） and its derivative copolymers were synthesized and used as phase transfer catalyst in the nucleophilic substitution reaction especially halogen exchange reactions....Cross-linked poly（diallyldimethylammonium chloride） and its derivative copolymers were synthesized and used as phase transfer catalyst in the nucleophilic substitution reaction especially halogen exchange reactions.In addition,the effect of hydrophilic-hydrophobic character of the polymers in the nucleophilic reactions was investigated.展开更多
OBJECTIVE: To evaluate the efficacy of Pistacia atlantica Desf. oleoresin essential oil on peptic ulcer(PU) and its antibacterial effect on metronidazole-resistant Helicobacter pylori, as well as chemi-cal composition...OBJECTIVE: To evaluate the efficacy of Pistacia atlantica Desf. oleoresin essential oil on peptic ulcer(PU) and its antibacterial effect on metronidazole-resistant Helicobacter pylori, as well as chemi-cal composition of the essential oil.METHODS: The essential oil was standardized using gas chromatography mass spectrometry(GC/MS) analysis. Acute toxicity of the essential oil was assessed in animal model. In vitro anti-Helicobacter pylori activity was performed through disc diffusion and minimum inhibitory concentration method. For gastroprotective assay, rats received Pistacia atlantica Desf. essential oil(25, 50 and 100 mg/kg orally) 1 h before induction of ulcer by ethanol.Macroscopic(ulcer index and protection rate) and microscopic examination were performed.RESULTS: The GC/MS analysis of the essential oil led to the identification of twenty constituents andα-pinene is predominant constituent. The essential oil was safe up to 2000 mg/kg. All Helicobacter pylori strains were susceptible to the essential oil and the MIC ranged from 275 to 1100 μg/m L. The ulcer index for treated groups was significantly reduced compared to control(P < 0.001) with EC50 value of 12.32 mg/kg. In microscopic examination, Pistacia atlantica attenuated destruction and necrosis of gastric tissue.CONCLUSION: Current study exhibited protective effect of standardized Pistacia atlantica essential oil against ethanol-induced gastric ulcer and its antibacterial activity on Helicobacter pylori. α-pinene might be the responsible agent.展开更多
Water stress is a major factor that limits agricultural crop production. Silicon(Si) is generally considered as a beneficial element for the growth of higher plants, especially for those grown under stressful environm...Water stress is a major factor that limits agricultural crop production. Silicon(Si) is generally considered as a beneficial element for the growth of higher plants, especially for those grown under stressful environment. This study was conducted to examine the effects of Si on growth and development of strawberry(Fragaria × ananassa ‘Camarosa') under water stress conditions. A factorial experiment, in a completely randomized design, was used to investigate the effects of three irrigation levels and four Si treatments consisting of 0, 5, 10, and 15 mmol·L^(-1) potassium silicate(K_2 SiO_3). The results showed that an increase in the levels of water stress caused a decrease in most of the quantitative characteristics such as specific leaf area, chlorophyll fluorescence, net photosynthesis rate, and stomata conductance; addition of Si significantly increased most of the mentioned factors; water stress increased electrolyte leakage, proline, and water use efficiency(WUE); Si treatment significantly decreased transpiration rate and improved chlorophyll content and WUE. Water stress stimulated mineral nutrient absorption whereas Si application decreased it under water stress. In conclusion, it was found that in most of the investigated factors, 10 mmol·L^(-1) potassium silicate had the best effect on growth and development of strawberry. Besides, Si application had beneficial effects on strawberry plants and the addition of it could alleviate water stress.展开更多
In this study,we developed multiple hybrid machine-learning models to address parameter optimization limitations and enhance the spatial prediction of landslide susceptibility models.We created a geographic informatio...In this study,we developed multiple hybrid machine-learning models to address parameter optimization limitations and enhance the spatial prediction of landslide susceptibility models.We created a geographic information system database,and our analysis results were used to prepare a landslide inventory map containing 359 landslide events identified from Google Earth,aerial photographs,and other validated sources.A support vector regression(SVR)machine-learning model was used to divide the landslide inventory into training(70%)and testing(30%)datasets.The landslide susceptibility map was produced using 14 causative factors.We applied the established gray wolf optimization(GWO)algorithm,bat algorithm(BA),and cuckoo optimization algorithm(COA)to fine-tune the parameters of the SVR model to improve its predictive accuracy.The resultant hybrid models,SVR-GWO,SVR-BA,and SVR-COA,were validated in terms of the area under curve(AUC)and root mean square error(RMSE).The AUC values for the SVR-GWO(0.733),SVR-BA(0.724),and SVR-COA(0.738)models indicate their good prediction rates for landslide susceptibility modeling.SVR-COA had the greatest accuracy,with an RMSE of 0.21687,and SVR-BA had the least accuracy,with an RMSE of 0.23046.The three optimized hybrid models outperformed the SVR model(AUC=0.704,RMSE=0.26689),confirming the ability of metaheuristic algorithms to improve model performance.展开更多
基金the Basic Research Project of the Korea Institute of Geoscience and Mineral Resources(KIGAM)Project of Environmental Business Big Data Platform and Center Construction funded by the Ministry of Science and ICT.
文摘The identification of landslide-prone areas is an essential step in landslide hazard assessment and mitigation of landslide-related losses.In this study,we applied two novel deep learning algorithms,the recurrent neural network(RNN)and convolutional neural network(CNN),for national-scale landslide susceptibility mapping of Iran.We prepared a dataset comprising 4069 historical landslide locations and 11 conditioning factors(altitude,slope degree,profile curvature,distance to river,aspect,plan curvature,distance to road,distance to fault,rainfall,geology and land-sue)to construct a geospatial database and divided the data into the training and the testing dataset.We then developed RNN and CNN algorithms to generate landslide susceptibility maps of Iran using the training dataset.We calculated the receiver operating characteristic(ROC)curve and used the area under the curve(AUC)for the quantitative evaluation of the landslide susceptibility maps using the testing dataset.Better performance in both the training and testing phases was provided by the RNN algorithm(AUC=0.88)than by the CNN algorithm(AUC=0.85).Finally,we calculated areas of susceptibility for each province and found that 6%and 14%of the land area of Iran is very highly and highly susceptible to future landslide events,respectively,with the highest susceptibility in Chaharmahal and Bakhtiari Province(33.8%).About 31%of cities of Iran are located in areas with high and very high landslide susceptibility.The results of the present study will be useful for the development of landslide hazard mitigation strategies.
文摘Diabetic nephropathy accounts for the most serious microvascular complication of diabetes mellitus. It is suggested that the prevalence of diabetic nephropathy will continue to increase in future posing a major challenge to the healthcare system resulting in increased morbidity and mortality. It occurs as a result of interaction between both genetic and environmental factors in individuals with both type 1 and type 2 diabetes. Genetic susceptibility has been proposed as an important factor for the development and progression of diabetic nephropathy, and various research efforts are being executed worldwide to identify the susceptibility gene for diabetic nephropathy. Numerous single nucleotide polymorphisms have been found in various genes giving rise to various gene variants which have been found to play a major role in genetic susceptibility to diabetic nephropathy. The risk of developing diabetic nephropathy is increased several times by inheriting risk alleles at susceptibility loci of various genes like ACE, IL, TNF-α, COL4A1, e NOS, SOD2, APOE, GLUT, etc. The identification of these genetic variants at a biomarker level could thus, allow the detection of those individuals at high risk for diabetic nephropathy which could thus help in the treatment, diagnosis and early prevention of the disease. The present review discusses about the various gene variants found till date to be associated with diabetic nephropathy.
基金supported by the National High Technology R&D Program of China (No. 2013AA065202)Zhejiang Provincial Natural Science Foundation (No. LZ13D010001)+1 种基金the National Natural Science Foundation of China (Nos. 41271489 and 21477112)the Specialized Research Fund for the Doctoral Program of Higher Education (No. 20120101110073)
文摘Biochar is produced from the pyrolysis of carbon-rich plant- and animal-residues under low oxygen and high temperature conditions and has been increasingly used for its positive role in soil compartmentalization through activities such as carbon sequestration and improving soil quality. Biochar is also considered a unique adsorbent due to its high specific surface area and highly carbonaceous nature. Therefore, soil amendments with small amounts of biochar could result in higher adsorption and, consequently, decrease the bioavailability of contaminants to microbial communities, plants, earthworms, and other organisms in the soil. However, the mechanisms affecting the environmental fate and behavior of organic contaminants, especially pesticides in biochar-amended soil, are not well understood. The purpose of this work is to review the role of biochar in primary processes, such as adsorption–desorption and leaching of pesticides. Biochar has demonstrable effects on the fate and effects of pesticides and has been shown to affect the degradation and bioavailability of pesticides for living organisms. Moreover, some key aspects of agricultural and environmental applications of biochar are highlighted.
文摘The microstructure and mechanical properties of Inconel 625 alloy fabricated by wire arc additive manufacturing process were evaluated under as-prepared and heat-treated conditions.A dendritic Ni-based solid solution phase along with(Nb,Ti)C carbide,Laves,and δ-Ni3Nb secondary phases were developed in the microstructure of the as-prepared alloy.Solution heat treatment led to the dissolution of Laves and Ni3Nb phases.In addition,dendrites were replaced with large columnar grains.Aging heat treatment resulted in the formation of grain boundary M23C6 carbide and nanometric γ''precipitates.Hardness,yield and tensile strengths,as well as elongation of the as-prepared part,were close to those of the cast alloy and its fracture occurred in a transgranular ductile mode.Solution heat treatment improved hardness and yield strength and declined the elongation,but it did not have a considerable impact on the tensile strength.Furthermore,aging heat treatment caused the tensile properties to deteriorate and changed the fracture to a mixture of transgranular ductile and intergranular brittle mode.
基金support of the Chinese Academy of Sciences through the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA15020100)support by ASI, under the dedicated eXTP agreements and agreement ASI-INAF (Grant No. 2017-14-H.O.)+3 种基金by INAF and INFN under project REDSOXsupport from the Deutsche Zentrum für Luft- und Raumfahrt, the German Aerospce Center (DLR)support of Science Centre (Grant No. 2013/10/M/ST9/00729)support from MINECO (Grant No. ESP2017-82674-R) and FEDER funds
文摘In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The mission aims at determining the equation of state of matter at supra-nuclear density, measuring effects of QED, and understanding the dynamics of matter in strong-field gravity. In addition to investigating fundamental physics, eXTP will be a very powerful observatory for astrophysics that will provide observations of unprecedented quality on a variety of galactic and extragalactic objects. In particular, its wide field monitoring capabilities will be highly instrumental to detect the electro-magnetic counterparts of gravitational wave sources.The paper provides a detailed description of:(1) the technological and technical aspects, and the expected performance of the instruments of the scientific payload;(2) the elements and functions of the mission, from the spacecraft to the ground segment.
文摘Quartz, the second most abundant mineral in the earth's crust, is a gangue mineral in practically every flotation process. Coarse quartz flotation has been a long standing problem in various mineral processing plants to reduce milling cost and increase valuable mineral recovery. Based on this, the effects of nanobubbles(NBs) and hydrodynamic parameters on coarse quartz particle flotation were systematically investigated. Mechanical flotation experiments were carried out using the 7 cm and 9 cm diameter impellers in order to produce different hydrodynamic conditions. 900–1300 rpm impeller speeds were used for the 7 cm diameter impeller and 554–786 rpm for the 9 cm diameter impeller. The results show that the presence of NBs increased the flotation recovery of à425 + 106 lm quartz by up to 21%. For the7 cm diameter impeller, the maximum flotation recoveries of 86.4% and 98% were obtained in the absence and presence of NBs at Reynolds number(Re) of 81,000 and 66,000, respectively. For the 9 cm diameter impeller, the maximum recoveries of 86.3% and 97.5% were obtained in the absence and presence of NBs at Re of 90,000 and 75,000, respectively. NBs increased the flotation rate constant up to 36%.
基金the funding received by a grant from Natural Sciences and Engineering Research of Canada(NSERC)for this study.
文摘Technical challenges have always been part of underground mining activities,however,some of these challenges grow in complexity as mining occurs in deeper and deeper settings.One such challenge is rock mass stability and the risk of rockburst events.To overcome these challenges,and to limit the risks and impacts of events such as rockbursts,advanced solutions must be developed and best practices implemented.Rockbursts are common in underground mines and substantially threaten the safety of personnel and equipment,and can cause major disruptions in mine development and operations.Rockbursts consist of violent wall rock failures associated with high energy rock projections in response to the instantaneous stress release in rock mass under high strain conditions.Therefore,it is necessary to develop a good understanding of the conditions and mechanisms leading to a rockburst,and to improve risk assessment methods.The capacity to properly estimate the risks of rockburst occurrence is essential in underground operations.However,a limited number of studies have examined and compared yet different empirical methods of rockburst.The current understanding of this important hazard in the mining industry is summarized in this paper to provide the necessary perspective or tools to best assess the risks of rockburst occurrence in deep mines.The various classifications of rockbursts and their mechanisms are discussed.The paper also reviews the current empirical methods of rockburst prediction,which are mostly dependent on geomechanical parameters of the rock such as uniaxial compressive strength of the rock,as well as its tensile strength and elasticity modulus.At the end of this paper,some current achievements and limitations of empirical methods are discussed.
基金the financial support of this research from Indian Institute of Technology Delhi
文摘Rock joints are often subjected to dynamic loads induced by earthquake and blasting during mining and rock cutting. Hence, cyclic shear load can be induced along the joints and it is important to evaluate the shear behavior of rock joint under this condition. In the present study, synthetic rock joints were prepared with plaster of Paris(Po P). Regular joints were simulated by keeping regular asperity with asperity angles of 15°-15° and 30°-30°, and irregular rock joints which are closer to natural joints were replicated by keeping the asperity angles of 15°-30° and 15°-45°. The sample size and amplitude of roughness were kept the same for both regular and irregular joints which were 298 mm×298 mm×125 mm and 5 mm, respectively. Shear test was performed on these joints using a large-scale direct shear testing machine by keeping the frequency and amplitude of shear load under constant cyclic condition with different normal stress values. As expected, the shear strength of rock joints increased with the increases in the asperity angle and normal load during the first cycle of shearing or static load. With the increase of the number of shear cycles, the shear strength decreased for all the asperity angles but the rate of reduction was more in case of high asperity angles. Test results indicated that shear strength of irregular joints was higher than that of regular joints at different cycles of shearing at low normal stress. Shearing and degradation of joint asperities on regular joints were the same between loading and unloading, but different for irregular joints. Shear strength and joint degradation were more significant on the slope of asperity with higher angles on the irregular joint until two angles of asperities became equal during the cycle of shearing and it started behaving like regular joints for subsequent cycles.
基金supported by the Science and Technology Project of State Grid Corporation of China(No.5455HJ180018).
文摘With the rapid growth of power systems measurements in terms of size and complexity,discovering statistical patterns for a large variety of real-world applications such as renewable energy prediction,demand response,energy disaggregation,and state estimation is considered a crucial challenge.In recent years,deep learning has emerged as a novel class of machine learning algorithms that represents power systems data via a large hypothesis space that leads to the state-of-the-art performance compared to most recent data-driven algorithms.This study explores the theoretical advantages of deep representation learning in power systems research.We review deep learning methodologies presented and applied in a wide range of supervised,unsupervised,and semi-supervised applications as well as reinforcement learning tasks.We discuss various settings of problems solved by discriminative deep models including stacked autoencoders and convolutional neural networks as well as generative deep architectures such as deep belief networks and variational autoencoders.The theoretical and experimental analysis of deep neural networks in this study motivates longterm research on optimizing this cutting-edge class of models to achieve significant improvements in the future power systems research.
基金supported by the National Natural Science Foundation of China(Grant Nos.41807192,41790441)Innovation Capability Support Program of Shaanxi(Grant No.2020KJXX-005)Natural Science Basic Research Program of Shaanxi(Grant Nos.2019JLM-7,2019JQ-094)。
文摘As threats of landslide hazards have become gradually more severe in recent decades,studies on landslide prevention and mitigation have attracted widespread attention in relevant domains.A hot research topic has been the ability to predict landslide susceptibility,which can be used to design schemes of land exploitation and urban development in mountainous areas.In this study,the teaching-learning-based optimization(TLBO)and satin bowerbird optimizer(SBO)algorithms were applied to optimize the adaptive neuro-fuzzy inference system(ANFIS)model for landslide susceptibility mapping.In the study area,152 landslides were identified and randomly divided into two groups as training(70%)and validation(30%)dataset.Additionally,a total of fifteen landslide influencing factors were selected.The relative importance and weights of various influencing factors were determined using the step-wise weight assessment ratio analysis(SWARA)method.Finally,the comprehensive performance of the two models was validated and compared using various indexes,such as the root mean square error(RMSE),processing time,convergence,and area under receiver operating characteristic curves(AUROC).The results demonstrated that the AUROC values of the ANFIS,ANFIS-TLBO and ANFIS-SBO models with the training data were 0.808,0.785 and 0.755,respectively.In terms of the validation dataset,the ANFISSBO model exhibited a higher AUROC value of 0.781,while the AUROC value of the ANFIS-TLBO and ANFIS models were 0.749 and 0.681,respectively.Moreover,the ANFIS-SBO model showed lower RMSE values for the validation dataset,indicating that the SBO algorithm had a better optimization capability.Meanwhile,the processing time and convergence of the ANFIS-SBO model were far superior to those of the ANFIS-TLBO model.Therefore,both the ensemble models proposed in this paper can generate adequate results,and the ANFIS-SBO model is recommended as the more suitable model for landslide susceptibility assessment in the study area considered due to its excellent accuracy and ef
基金the Natural Sciences and Engineering Research Council of Canada(NSERC)an NSERC-FPinnovations CRD grant for supporting this researchMcGill University for a MEDA fellowship.
文摘As the most abundant biopolymer on the earth,cellulose has recently gained significant attention in the development of antibacterial biomaterials.Biodegradability,renewability,strong mechanical properties,tunable aspect ratio,and low density offer tremendous possibilities for the use of cellulose in various fields.Owing to the high number of reactive groups(i.e.,hydroxyl groups)on the cellulose surface,it can be readily functionalized with various functional groups,such as aldehydes,carboxylic acids,and amines,leading to diverse properties.In addition,the ease of surface modification of cellulose expands the range of compounds which can be grafted onto its structure,such as proteins,polymers,metal nanoparticles,and antibiotics.There are many studies in which cellulose nano-/microfibrils and nanocrystals are used as a support for antibacterial agents.However,little is known about the relationship between cellulose chemical surface modification and its antibacterial activity or biocompatibility.In this study,we have summarized various techniques for surface modifications of cellulose nanostructures and its derivatives along with their antibacterial and biocompatibility behavior to develop non-leaching and durable antibacterial materials.Despite the high effectiveness of surface-modified cellulosic antibacterial materials,more studies on their mechanism of action,the relationship between their properties and their effectivity,and more in vivo studies are required.
基金supported by the National Natural Science Foundation of China (No. 41301245)the Strategic Priority Research Program of Chinese Academy of Sciences (No. XDA05050506)+1 种基金the Special Program for National Science & Technology Basic Work of China (No. 2014FY110200A13)the Fundamental Research Funds for the Central Universities of China (No. XDJK2013B043)
文摘The diurnal fluctuation in soil temperature may influence soil organic carbon （SOC） mineralization, but there is no consensus on SOC mineralization response to the cyclical fluctuation in soil temperature. A 56-d incubation experiment was conducted to investigate the effects of constant and variable temperatures on SOC mineralization. Three soils were collected from the karst region in western Guizhou Province, southwestern China, including a limestone soil under forest, a limestone soil under crops and a yellow soil under crops. According to the World Reference Base （WRB） classification, the two limestone soils were classified as Haplic Luvisols and the yellow soil as a Dystric Luvisol. These soils were incubated at three constant temperatures （15, 20 and 25 ℃） and cyclically fluctuating temperatures （diurnal cycle between 15 and 25 ℃）. The results showed that the 56-d cumulative SOC mineralized （C56） at the fluctuating temperatures was between those at constant 15 and 25 ℃, suggesting that the cumulative SOC mineralization was restricted by temperature range. The SOC mineralization responses to the fluctuating temperatures were different among the three soils, especially in contrast to those at constant 20 ~C. Compared with constant 20 ℃, significant （P 〈 0.05） decreases and increases in C56 value were found in the limestone soil under forest and yellow soil under crops at the fluctuating temperatures, respectively. At the fluctuating temperatures, the forest soil with lower temperature coefficient Q10 （the relative change in SOC mineralization rate as a result of increasing the temperature by 10 ℃） had a significantly （P 〈 0.05） lower SOC mineralization intensity than the two cropland soils. These indicated that differences in temperature pattern （constant or fluctuating） could significantly influence SOC mineralization, and SOC mineralization responses to the fluctuating temperatures might be affected by soil characteristics. Moreover, the warmer temperatures
文摘Friction and wear phenomena encountered in mechanical systems with moving components are directly related to efficiency,reliability and life of the system.Hence,minimizing and controlling these phenomena to achieve the desired system performance is crucial.Among the numerous strategies developed for reducing friction and wear,coatings have been successfully utilized in various engineering applications to mitigate tribological problems.One of the benefits of coatings is that they may be fabricated using a variety of materials in several different forms and structures to satisfy the requirements of the operating conditions.Among many types,coatings that are comprised of a combination of materials in the form of a multilayer have been gaining much interest due to the added degree of freedom in tailoring the coating property.In this paper,the properties and development status of multilayer coating systems for tribological applications were reviewed with the aim to gain a better understanding regarding their advantages and limitations.Specifically,focus was given to Ti-based and Cr-based coatings since Ti and Cr were identified as important elements in multilayer coating applications.Emphasis was given to materials,design concepts,mechanical properties,deposition method,and friction and wear characteristics of these types of coatings.
基金This work was conducted at the Physical Modeling and Centrifuge Laboratory of the Soil Mechanics and Foundation Engineering Department in the School of Civil Engineering,University of Tehran
文摘Seismic ground faulting is the greatest hazard for continuous buried pipelines.Over the years,researchers have attempted to understand pipeline behavior mostly via numerical modeling such as the finite element method.The lack of well-documented field case histories of pipeline failure from seismic ground faulting and the cost and complicated facilities needed for full-scale experimental simulation mean that a centrifuge-based method to determine the behavior of pipelines subjected to faulting is best to verify numerical approaches.This paper presents results from three centrifuge tests designed to investigate continuous buried steel pipeline behavior subjected to normal faulting.The experimental setup and procedure are described and the recorded axial and bending strains induced in a pipeline are presented and compared to those obtained via analytical methods.The influence of factors such as faulting offset,burial depth and pipe diameter on the axial and bending strains of pipes and on ground soil failure and pipeline deformation patterns are also investigated.Finally,the tensile rupture of a pipeline due to normal faulting is investigated.
文摘The dissimilar joining of biodegradable magnesium alloy to pure commercial titanium by rotational friction welding with rotational speeds of 1100,1200 and 1300 r/min for the production of bio-screw was investigated.The metallographic analysis revealed that a good joining was obtained at the Ti/Mg alloy joint.On the magnesium alloy side,various regions such as the weld center zone(WCZ),dynamic recrystallization zone(DRX),thermo-mechanically affected zone(TMAZ)and partially deformed zone(PDZ)were observed.The highest tensile and shear strengths were 173 and 103.2 MPa,respectively at a rotational speed of 1300 r/min.The Ti/Mg alloy dissimilar friction welded joint failed at the vicinity of the intermetallic zone containing Ti3Al phase.The hardness values from the base metal magnesium alloy to the joining point increased mainly due to grain refinement(8.57μm in diameter)and the presence of titanium particles,while the hardness values were constant on the titanium side.It was also found that the corrosion rate of the Ti/Mg alloy joint was higher compared with that of the Ti and Mg alloy from the immersion studies.Additionally,the sample with a rotational speed of 1300 r/min showed better biocompatibility and a cell viability of 98.12%due to better corrosion resistance.
文摘Cross-linked poly（diallyldimethylammonium chloride） and its derivative copolymers were synthesized and used as phase transfer catalyst in the nucleophilic substitution reaction especially halogen exchange reactions.In addition,the effect of hydrophilic-hydrophobic character of the polymers in the nucleophilic reactions was investigated.
基金Tehran University of Medical Sciences(TUMS,Evaluation of the Effect of P.atlantica on Ethanol-Induced Gastric Ulcer in Rats,No.94018627690)
文摘OBJECTIVE: To evaluate the efficacy of Pistacia atlantica Desf. oleoresin essential oil on peptic ulcer(PU) and its antibacterial effect on metronidazole-resistant Helicobacter pylori, as well as chemi-cal composition of the essential oil.METHODS: The essential oil was standardized using gas chromatography mass spectrometry(GC/MS) analysis. Acute toxicity of the essential oil was assessed in animal model. In vitro anti-Helicobacter pylori activity was performed through disc diffusion and minimum inhibitory concentration method. For gastroprotective assay, rats received Pistacia atlantica Desf. essential oil(25, 50 and 100 mg/kg orally) 1 h before induction of ulcer by ethanol.Macroscopic(ulcer index and protection rate) and microscopic examination were performed.RESULTS: The GC/MS analysis of the essential oil led to the identification of twenty constituents andα-pinene is predominant constituent. The essential oil was safe up to 2000 mg/kg. All Helicobacter pylori strains were susceptible to the essential oil and the MIC ranged from 275 to 1100 μg/m L. The ulcer index for treated groups was significantly reduced compared to control(P < 0.001) with EC50 value of 12.32 mg/kg. In microscopic examination, Pistacia atlantica attenuated destruction and necrosis of gastric tissue.CONCLUSION: Current study exhibited protective effect of standardized Pistacia atlantica essential oil against ethanol-induced gastric ulcer and its antibacterial activity on Helicobacter pylori. α-pinene might be the responsible agent.
文摘Water stress is a major factor that limits agricultural crop production. Silicon(Si) is generally considered as a beneficial element for the growth of higher plants, especially for those grown under stressful environment. This study was conducted to examine the effects of Si on growth and development of strawberry(Fragaria × ananassa ‘Camarosa') under water stress conditions. A factorial experiment, in a completely randomized design, was used to investigate the effects of three irrigation levels and four Si treatments consisting of 0, 5, 10, and 15 mmol·L^(-1) potassium silicate(K_2 SiO_3). The results showed that an increase in the levels of water stress caused a decrease in most of the quantitative characteristics such as specific leaf area, chlorophyll fluorescence, net photosynthesis rate, and stomata conductance; addition of Si significantly increased most of the mentioned factors; water stress increased electrolyte leakage, proline, and water use efficiency(WUE); Si treatment significantly decreased transpiration rate and improved chlorophyll content and WUE. Water stress stimulated mineral nutrient absorption whereas Si application decreased it under water stress. In conclusion, it was found that in most of the investigated factors, 10 mmol·L^(-1) potassium silicate had the best effect on growth and development of strawberry. Besides, Si application had beneficial effects on strawberry plants and the addition of it could alleviate water stress.
基金supported by the Basic Research Project of the Korea Institute of Geoscience and Mineral Resources(KIGAM)Project of Environmental Business Big Data Platform and Center Construction funded by the Ministry of Science and ICT。
文摘In this study,we developed multiple hybrid machine-learning models to address parameter optimization limitations and enhance the spatial prediction of landslide susceptibility models.We created a geographic information system database,and our analysis results were used to prepare a landslide inventory map containing 359 landslide events identified from Google Earth,aerial photographs,and other validated sources.A support vector regression(SVR)machine-learning model was used to divide the landslide inventory into training(70%)and testing(30%)datasets.The landslide susceptibility map was produced using 14 causative factors.We applied the established gray wolf optimization(GWO)algorithm,bat algorithm(BA),and cuckoo optimization algorithm(COA)to fine-tune the parameters of the SVR model to improve its predictive accuracy.The resultant hybrid models,SVR-GWO,SVR-BA,and SVR-COA,were validated in terms of the area under curve(AUC)and root mean square error(RMSE).The AUC values for the SVR-GWO(0.733),SVR-BA(0.724),and SVR-COA(0.738)models indicate their good prediction rates for landslide susceptibility modeling.SVR-COA had the greatest accuracy,with an RMSE of 0.21687,and SVR-BA had the least accuracy,with an RMSE of 0.23046.The three optimized hybrid models outperformed the SVR model(AUC=0.704,RMSE=0.26689),confirming the ability of metaheuristic algorithms to improve model performance.
