A numerical model based on measured fictive temperature distributions is explored to evaluate the residual stress fields of CO_(2)laser-annealed mitigated fused silica damage sites.The proposed model extracts the resi...A numerical model based on measured fictive temperature distributions is explored to evaluate the residual stress fields of CO_(2)laser-annealed mitigated fused silica damage sites.The proposed model extracts the residual strain from the differences in thermoelastic contraction of fused silica with different fictive temperatures from the initial frozen-in temperatures to ambient temperature.The residual stress fields of mitigated damage sites for the CO_(2)laser-annealed case are obtained by a finite element analysis of equilibrium equations and constitutive equations.The simulated results indicate that the proposed model can accurately evaluate the residual stress fields of laser-annealed mitigated damage sites with a complex thermal history.The calculated maximum hoop stress is in good agreement with the reported experimental result.The estimated optical retardance profiles from the calculated radial and hoop stress fields are consistent with the photoelastic measurements.These results provide sufficient evidence to demonstrate the suitability of the proposed model for describing the residual stresses of mitigated fused silica damage sites after CO_(2)laser annealing.展开更多
As Egyptian oil and gas downstream information technology has grown digitally over the past decade, security breaches against these digitally connected systems have also increased. These cyber security threats could h...As Egyptian oil and gas downstream information technology has grown digitally over the past decade, security breaches against these digitally connected systems have also increased. These cyber security threats could have devastating effects on the operations and reputation of these companies. Preventing such cyberattacks is crucial. Especially, with the significance of the Egyptian oil and gas downstream sector to the local economy and the fact that many of these connected systems are sometimes managed remotely. This paper examines the value of the ISO 27001 standard in mitigating the effect of cyber threat and seeks to inspire decision-makers to the importance of the proactive measures to strengthen their organization’s cybersecurity posture and protect information critical assets. The study stresses the importance of improving the local educational system to bridge the gap between supply and demand for cybersecurity specialists by implementing a structured approach that emphasizes behavior modification to get a high return on investment in cybersecurity awareness.展开更多
Background:Forest based climate mitigation emerged as a key component of the Paris Agreement,and thus re-quires robust science to reduce uncertainties related to such strategies.The aim of this study was to assess and...Background:Forest based climate mitigation emerged as a key component of the Paris Agreement,and thus re-quires robust science to reduce uncertainties related to such strategies.The aim of this study was to assess and compare the cumulative effects on carbon dynamics of forest management and climate change on boreal and northern temperate forest sector in eastern Canada for the 2020–2100 period.Methods:We used the spatially explicit forest landscape model LANDIS-II and its extension Forest Carbon Suc-cession,in conjunction with the Carbon Budget Model for Harvested Wood Products framework.We simulated the dynamics of forest composition and carbon flows from forest ecosystems to wood products and their substitution effect on markets under increasing climate forcing,according to a tonne-year approach.Simulations were con-ducted for a series of forest management scenarios based on realistic practices principally by clearcut in the boreal territory and continuous-cover forestry in the northern temperate one.These scenarios included:i)a business-as-usual scenario(BaU),representing the current management strategy,ii)increased harvesting by 6.3%to 13.9%,iii)increased conservation(i.e.reduced harvesting by 11.1%to 49.8%),iiii)and a scenario representing the natural evolution of the forest landscape(i.e.without any management activity).Results:Our study revealed that increasing harvesting levels had contrasting effects on the mitigation potential in northern temperate(enhance net sequestration)and boreal forest sector(enhance net emissions)in comparison to the BaU from 2040 onwards,regardless of the future climate.Carbon storage in wood products and the substi-tution effect were not sufficient to offset carbon emissions from ecosystems.Moreover,climate change had a strong impact on the capacity of both landscapes to act as carbon sinks.Northern temperate landscapes became a net source of carbon over time due to their greater vulnerability to climate change than boreal landscapes.Conclusions:Our study highlights the need to consider the initial landscape characteristics in simulations to maximize the mitigation potential of alternative forest management strategies.The optimal management solution can be very different according to the characteristics of forest ecosystems.This opens the possibility of optimizing management for specific forest stands,with the objective of maximizing the mitigation potential of a given landscape.展开更多
Background:Heat stress is a significant problem in the poultry industry,causing a severe economic loss due to its detrimental effects on chickens’health and performance.Dried plum(DP)is a good source of minerals,vita...Background:Heat stress is a significant problem in the poultry industry,causing a severe economic loss due to its detrimental effects on chickens’health and performance.Dried plum(DP)is a good source of minerals,vitamins,antioxidants,and phenolic compounds.Studies have suggested that DP has several health benefits,such as maintaining the body’s redox system,immune status,and calcium hemostasis.Based on the health benefits of DP,we hypothesized that the dietary supplementation of DP would alleviate the detrimental effects of heat stress on broiler chickens.Results:To test the hypothesis,day-old broiler chicks(n=72)were randomly allocated to three treatment groups(n=24/group):no heat stress(NHS),heat stress(HS),and heat stress with dried plum(HS+DP),and reared under standard conditions.The inclusion of 2.5%DP in the feed of the HS+DP group was made during the treatment period,while birds in other groups were provided with a standard finisher diet.After 21 days,birds in the HS and HS+DP groups were exposed to cyclic heat stress conditions(33℃ for 8 h during daytime)for 3 weeks,while those in the NHS group were reared under normal conditions(22-24℃).Weekly body weight and feed intake were recorded to calculate the average daily gain(ADG),average daily feed intake(ADFI),and feed conversion ratio(FCR).Heat stress significantly decreased the final body weight,ADG,ADFI,and increased FCR compared to the NHS group,whereas dietary supplementation of DP significantly improved these growth performance parameters compared to the HS group.Furthermore,supplementation of DP significantly increased the expression of heat shock protein-related genes(HSF1,HSF3,HSP70,and HSP90),antioxidant-related genes(SOD1,SOD2,GPX1,GPX3,PRDX1,and TXN),tight junction-related genes(CLDN1,and OCLN),and immune-related genes(IL4,MUC2)in the ileum as compared to the HS group.The microbiota analysis showed significant enrichment of Bacillales,Christensenellaceae,Bacillaceae,Peptostreptococcaceae,and Anaerotruncus in heat-stressed birds supplemented with DP as compared to the HS group.Further,DP supplementation also significantly increased the concentration of acetate,propionate,and total VFA in the cecal digesta of the HS+DP group as compared to the HS group.Conclusion:These findings suggest that DP supplementation effectively improved the growth performances and gut health parameters in the heat-stressed birds.Thus,dried plum can be a potential feed supplement to mitigate heat stress in broiler chickens.展开更多
In soil biota,higher and enduring concentration of heavy metals like cadmium(Cd)is hazardous and associated with great loss in growth,yield,and quality parameters of most of the crop plants.Recently,in-situ applicatio...In soil biota,higher and enduring concentration of heavy metals like cadmium(Cd)is hazardous and associated with great loss in growth,yield,and quality parameters of most of the crop plants.Recently,in-situ applications of eco-friendly stabilizing agents in the form of organic modifications have been utilized to mitigate the adverse effects of Cd-toxicity.This controlled experiment was laid down to appraise the imprints of various applied organic amendments namely poultry manure(PM),farmyard manure(FYM),and sugarcane press mud(PS)to immobilize Cd in polluted soil.Moreover,phytoavailability of Cd in wheat was also accessed under an alkaline environment.Results revealed that the addition of FYM(5–10 ton ha^(-1))in Cd-contaminated soil significantly increased germination rate,leaf chlorophyll content,plant height,spike length,biological and grain yield amongst all applied organic amendments.Moreover,the addition of FYM(5–10 ton ha^(-1))also reduced the phytoavailability of Cd by 73–85%in the roots,57–83%in the shoots,and 81–90%in grains of wheat crop.Thus,it is affirmed that incorporation of FYM(5–10 ton ha^(-1))performed better to enhance wheat growth and yield by remediating Cd.Thus,the application of FYM(5–10 ton ha^(-1))reduced the toxicity induced by Cd to plants by declining its uptake and translocation as compared to all other applied organic amendments to immobilize Cd under sandy alkaline polluted soil.展开更多
Three-dimensional(3 D)TCAD simulations demonstrate that reducing the distance between the well boundary and N-channel metal-oxide semiconductor(NMOS)transistor or P-channel metal-oxide semiconductor(PMOS)transistor ca...Three-dimensional(3 D)TCAD simulations demonstrate that reducing the distance between the well boundary and N-channel metal-oxide semiconductor(NMOS)transistor or P-channel metal-oxide semiconductor(PMOS)transistor can mitigate the cross section of single event upset(SEU)in 14-nm complementary metal-oxide semiconductor(CMOS)bulk Fin FET technology.The competition of charge collection between well boundary and sensitive nodes,the enhanced restoring currents and the change of bipolar effect are responsible for the decrease of SEU cross section.Unlike dualinterlock cell(DICE)design,this approach is more effective under heavy ion irradiation of higher LET,in the presence of enough taps to ensure the rapid recovery of well potential.Besides,the feasibility of this method and its effectiveness with feature size scaling down are discussed.展开更多
With the surge of human population, the need for transportation of goods and people also concomitantly increases, resulting in urban air pollution through emission from motorized traffic especially in developing count...With the surge of human population, the need for transportation of goods and people also concomitantly increases, resulting in urban air pollution through emission from motorized traffic especially in developing countries. The extent of environmental pollution in an urban setting is significantly influenced by the pollutants of vehicular fuel combustion. Many effective measures are required in cities to sequester carbon thereby helping to reduce automobile pollution. Roadside greeneries can serve as ecological elements which reduce the concentration of pollutants from vehicular emissions by their direct involvement in absorbing vehicular emitted carbon. In this context, in this study an attempt has been taken to assess contribution of roadside greeneries in absorbing vehicular carbon dioxide emission. A case study has been conducted on arterial roads of mega city Dhaka to quantify the vehicular carbon emission and correlate it with roadside trees to absorb the emitted carbon dioxide. It is noted that in Dhaka city, carbon dioxide is accounted for more than ninety percent of air pollution. To achieve our goals, two busiest arterial roads (namely Mirpur Road and Rokeya Shoroni Road) were taken into account to quantify vehicular carbon emission as well as assess carbon absorption by roadside greeneries. Carbon absorption by different sizes of trees has been quantified using the amount of woody biomass. In addition, absorption by grass-shrubs-herbs has been quantified by the area they cover. The results thus obtained show that indeed the road with more side greeneries absorbs more vehicular emitted carbon dioxide. It is therefore evident that plantation of more roadside trees is an effective measure of reducing air pollution and consequently turning a city to become healthier and more suitable for living.展开更多
Within the agricultural sector,animal production contributes to 14.5%of global anthropogenic greenhouse gas emissions and produces around 37%of global CH_(4) emissions,mainly due to ruminal fermentation in ruminants.O...Within the agricultural sector,animal production contributes to 14.5%of global anthropogenic greenhouse gas emissions and produces around 37%of global CH_(4) emissions,mainly due to ruminal fermentation in ruminants.Over 90%of CH_(4) is synthesized by methanogens in the rumen during carbohydrate fermentation.According to different substrates,methanogenesis pathways can be divided into four categories:(1)hydrogenotrophic pathway;(2)acetoclastic pathway;(3)methyl dismutation pathway;and(4)methylreducing pathway.Based on the principle of biochemical reactions in the methanogenesis pathways,this paper reviews the latest publications on CH_(4) decreases in ruminants and described three nutritional strategies in terms of dietary nutrient manipulation(feeding management,feed composition,forage quality and lipids),microbial manipulation(ionophore,defaunation,methanogen inhibitors and probiotics),and chemical manipulation(nitrate,organic acids,plant secondary metabolites and phlorotannins,or halides in seaweeds).For each mitigation strategy,the review discusses effectiveness for decreasing CH_(4) emissions,application prescription,and feed safety based on results from in vitro and in vivo studies.This review summarizes different nutritional strategies to mitigate CH_(4) emissions and proposed comprehensive approaches for future feeding interventions and applications in the livestock industry.展开更多
With the surge of demand for instant high power in miniaturized electronic and mechanical systems,supercapacitors(SCs)are considered as one of the viable candidates to fulfill the requirements.Thus,long-term resilienc...With the surge of demand for instant high power in miniaturized electronic and mechanical systems,supercapacitors(SCs)are considered as one of the viable candidates to fulfill the requirements.Thus,long-term resilience and superior energy density associated with self-discharge in SCs are obviously critical,but securing electrode materials,which can meet both benefits of SCs and persist charged potential for a comparatively prolonged duration,are still elusive.Herein,hierarchically refined nickel-sulfide heterostructure(CuO-NS)on CuO(CO)scaffold is achieved through optimized film formation,exhibiting a threefold improvement in the essential electrochemical characteristics and outstanding capacitance retention(∼5%loss).Self-discharge behavior and its mechanism are systematically investigated via morphological control and nanostructural evolution.Furthermore,significant mitigation of self-discharge owing to an increase in surface area and refined nanostructure is displayed.Remarkably,CuO-NS2(20 cycle overcoating)based SC can retain over 60%of the charged potential for a complete voltage holding and a self-discharge test for 16 h.An appealing demonstration of wireless power transmission in burst mode is demonstrated for secure digital(SD)card data writing,powered by SCs,which substantiates that it can be readily leveraged in power management systems.This enables us to realize one of the envisioned applications soon.展开更多
Background The red macroalgae Asparagopsis is an effective methanogenesis inhibitor due to the presence of halogenated methane(CH_(4))analogues,primarily bromoform(CHBr_(3)).This study aimed to investigate the degrada...Background The red macroalgae Asparagopsis is an effective methanogenesis inhibitor due to the presence of halogenated methane(CH_(4))analogues,primarily bromoform(CHBr_(3)).This study aimed to investigate the degradation process of CHBr3 from A taxiformis in the rumen and whether this process is diet-dependent.An in vitro batch culture system was used according to a 2×2 factorial design,assessing two A taxiformis inclusion rates[0(CTL)and 2%DM diet(AT)]and two diets[high-concentrate(HC)and high-forage diet(HF)].Incubations lasted for 72 h and samples of headspace and fermentation liquid were taken at 0,0.5,1,3,6,8,12,16,24,48 and 72 h to assess the pattern of degradation of CHBr_(3) into dibromomethane(CH_(2)Br_(2))and fermentation parameters.Additionally,an in vitro experiment with pure cultures of seven methanogens strains(Methanobrevibacter smithii,Methanobrevibacter ruminantium,Methanosphaera stadtmanae,Methanosarcina barkeri,Methanobrevibacter millerae,Methanorhermobacter wolfei and Methanobacterium mobile)was conducted to test the effects of increasing concentrations of CHBr3(0.4,2,10and 50μmol/L).Results The addition of AT significantly decreased CH_(4) production(P=0.002)and the acetate:propionate ratio(P=0.003)during a 72-h incubation.The concentrations of CHBr_(3) showed a rapid decrease with nearly 90%degraded within the first 3 h of incubation.On the contrary,CH_(2)Br_(2) concentration quickly increased during the first 6 h and then gradually decreased towards the end of the incubation.Neither CHBr_(3) degradation nor CH_(2)Br_(2) synthesis were affected by the type of diet used as substrate,suggesting that the fermentation rate is not a driving factor involved in CHBr_(3)degradation.The in vitro culture of methanogens showed a dose-response effect of CHBr3 by inhibiting the growth of M.smithii,M.ruminantium,M.stadtmanae,M.barkeri,M.millerae,M.wolfei,and M.mobile.Conclusions The present work demonstrated that CHBr_(3) from A.taxiformis is quickly degraded to CH_(2)Br_(2)in the rumen and that the fermentation rate promoted by different diets is not a driving factor involved in CHBr_(3)degradation.展开更多
In recent years,explosion shock wave has been considered as a signature injury of the current military conflicts.Although strong shock wave is lethal to the human body,weak shock wave can cause many more lasting conse...In recent years,explosion shock wave has been considered as a signature injury of the current military conflicts.Although strong shock wave is lethal to the human body,weak shock wave can cause many more lasting consequences.To investigate the protection ability and characteristics of flexible materials and structures under weak shock wave loading,the blast wave produced by TNT explosive is loaded on the polyurethane foam with the density of 200.0 kg/m3(F-200)and 400.0 kg/m3(F-400),polyurea with the density of 1100.0 kg/m^(3)(P-1100)and structures composed of the two materials,which are intended for individual protection.Experimental results indicate that the shock wave is attenuated to weak pressure disturbance after interacting with the flexible materials which are not damaged.The shock wave protective capability of single-layer materials is dependent on their thickness,density and microscopic characteristics.The overpressure,maximum pressure rise rate and impulse of transmitted wave decrease exponentially with increase in sample thickness.For the same thickness,F-400 provides better protective capability than F-200 while P-1100 shows the best protective capability among the three materials.In this study,as the materials are not destroyed,F-200 with a thickness more than10.0 mm,F-400 with a thickness more than 4.0 mm,and P-1100 with a thickness more than 1.0 mm can attenuate the overpressure amplitude more than 90.0%.Further,multi-layer flexible composites are designed.Different layer layouts of designed structures and layer thickness of the single-layer materials can affect the protective performance.Within the research range,the structure in which polyurea is placed on the impact side shows the optimal shock wave protective performance,and the thicknesses of polyurea and polyurethane foam are 1.0 mm and 4.0 mm respectively.The overpressure attenuation rate reached maximum value of 93.3%and impulse attenuation capacity of this structure are better than those of single-layer polyurea and polyurethane foam with higher areal density.展开更多
An in-house code,CONTHAC-3D,was developed to calculate and analyze thermal-hydraulic phenomena in containments during severe accidents.CONTHAC-3D is a three-dimensional computational fluid dynamics code that can be ap...An in-house code,CONTHAC-3D,was developed to calculate and analyze thermal-hydraulic phenomena in containments during severe accidents.CONTHAC-3D is a three-dimensional computational fluid dynamics code that can be applied to predict gas flow,diffusion,and steam condensation in a containment during a severe hypothetical accident,as well as to obtain an estimate of the local hydrogen concentration in various zones of the containment.CONTHAC-3D was developed using multiple models to simulate the features of the proprietary systems and equipment of HPR1000 and ACP100,such as the passive cooling system,passive autocatalytic recombiners and the passive air cooling system.To validate CONTHAC-3D,a GX6 test was performed at the Battelle Model Containment facility.The hydrogen concentration and temperature monitored by the GX6 test are accurately predicted by CONTHAC-3D.Subsequently,the hydrogen distribution in the HPR1000 containment during a severe accident was studied.The results show that the hydrogen removal rates calculated using CONTHAC-3D for different types of PARs agree well with the theoretical values,with an error of less than 1%.As the accident progresses,the hydrogen concentration in the lower compartment becomes higher than that in the large space,which implies that the lower compartment has a higher hydrogen risk than the dome and large space at a later stage of the accident.The amount of hydrogen removed by the PARs placed on the floor of the compartment is small;therefore,raising the installation height of these recombiners appropriately is recommended.However,we do not recommend installing all autocatalytic recombiners at high positions.The study findings in regard to the hydrogen distribution in the HPR1000 containment indicate that CONTHAC-3D can be applied to the study of hydrogen risk containment.展开更多
This paper provides a comprehensive overview on coastal protection and hazard mitigation by mangroves.Previous stud-ies have made great strides to understand the mechanisms and influencing factors of mangroves’protec...This paper provides a comprehensive overview on coastal protection and hazard mitigation by mangroves.Previous stud-ies have made great strides to understand the mechanisms and influencing factors of mangroves’protection function,including wave energy dissipation,storm surge damping,tsunami mitigation,adjustment to sea level rise and wind speed reduction,which are sys-tematically summarized in this study.Moreover,the study analyzes the extensive physical models,based on indoor flume experi-ments and numerical models,that consider the interaction between mangroves and hydrodynamics,to help our understanding of mangrove-hydrodynamic interactions.Additionally,quantitative approaches for valuing coastal protection services provided by man-groves,including index-based and process-resolving approaches,are introduced in detail.Finally,we point out the limitations of previous studies,indicating that efforts are still required for obtaining more long-term field observations during extreme weather events,to create more real mangrove models for physical experiments,and to develop numerical models that consider the flexible properties of mangroves to better predict wave propagation in mangroves having complex morphology and structures.展开更多
The phenomenology involved in severe accidents in nuclear reactors is highly complex.Currently,integrated analysis programs used for severe accident analysis heavily rely on custom empirical parameters,which introduce...The phenomenology involved in severe accidents in nuclear reactors is highly complex.Currently,integrated analysis programs used for severe accident analysis heavily rely on custom empirical parameters,which introduce considerable uncertainty.Therefore,in recent years,the field of severe accidents has shifted its focus toward applying uncertainty analysis methods to quantify uncertainty in safety assessment programs,known as“best estimate plus uncertainty(BEPU).”This approach aids in enhancing our comprehension of these programs and their further development and improvement.This study concentrates on a third-generation pressurized water reactor equipped with advanced active and passive mitigation strategies.Through an Integrated Severe Accident Analysis Program(ISAA),numerical modeling and uncertainty analysis were conducted on severe accidents resulting from large break loss of coolant accidents.Seventeen uncertainty parameters of the ISAA program were meticulously screened.Using Wilks'formula,the developed uncertainty program code,SAUP,was employed to carry out Latin hypercube sampling,while ISAA was employed to execute batch calculations.Statistical analysis was then conducted on two figures of merit,namely hydrogen generation and the release of fission products within the pressure vessel.Uncertainty calculations revealed that hydrogen production and the fraction of fission product released exhibited a normal distribution,ranging from 182.784 to 330.664 kg and from 15.6 to 84.3%,respectively.The ratio of hydrogen production to reactor thermal power fell within the range of 0.0578–0.105.A sensitivity analysis was performed for uncertain input parameters,revealing significant correlations between the failure temperature of the cladding oxide layer,maximum melt flow rate,size of the particulate debris,and porosity of the debris with both hydrogen generation and the release of fission products.展开更多
Wheel polygonal wear can immensely worsen wheel/rail interactions and vibration performances of the train and track,and ultimately,lead to the shortening of service life of railway components.At present,wheel/rail med...Wheel polygonal wear can immensely worsen wheel/rail interactions and vibration performances of the train and track,and ultimately,lead to the shortening of service life of railway components.At present,wheel/rail medium-or high-frequency frictional interactions are perceived as an essential reason of the high-order polygonal wear of railway wheels,which are potentially resulted by the flexible deformations of the train/track system or other external excitations.In this work,the effect of wheel/rail flexibility on polygonal wear evolution of heavy-haul locomotive wheels is explored with aid of the long-term wheel polygonal wear evolution simulations,in which different flexible modeling of the heavy-haul wheel/rail coupled system is implemented.Further,the mitigation measures for the polygonal wear of heavy-haul locomotive wheels are discussed.The results point out that the evolution of polygonal wear of heavy-haul locomotive wheels can be veritably simulated with consideration of the flexible effect of both wheelset and rails.Execution of mixed-line operation of heavy-haul trains and application of multicut wheel re-profiling can effectively reduce the development of wheel polygonal wear.This research can provide a deep-going understanding of polygonal wear evolution mechanism of heavy-haul locomotive wheels and its mitigation measures.展开更多
To improve the anti-jamming and interference mitigation ability of the UAV-aided communication systems, this paper investigates the channel selection optimization problem in face of both internal mutual interference a...To improve the anti-jamming and interference mitigation ability of the UAV-aided communication systems, this paper investigates the channel selection optimization problem in face of both internal mutual interference and external malicious jamming. A cooperative anti-jamming and interference mitigation method based on local altruistic is proposed to optimize UAVs’ channel selection. Specifically, a Stackelberg game is modeled to formulate the confrontation relationship between UAVs and the jammer. A local altruistic game is modeled with each UAV considering the utilities of both itself and other UAVs. A distributed cooperative anti-jamming and interference mitigation algorithm is proposed to obtain the Stackelberg equilibrium. Finally, the convergence of the proposed algorithm and the impact of the transmission power on the system loss value are analyzed, and the anti-jamming performance of the proposed algorithm can be improved by around 64% compared with the existing algorithms.展开更多
The misfolding and aggregation ofα-synuclein(α-syn)is closely associated with Parkinson’s disease(PD).Here,chiral dimanganese trioxide(Mn_(2)O_(3))nanoparticles(NPs)were prepared for PD treatment enhanced by a noni...The misfolding and aggregation ofα-synuclein(α-syn)is closely associated with Parkinson’s disease(PD).Here,chiral dimanganese trioxide(Mn_(2)O_(3))nanoparticles(NPs)were prepared for PD treatment enhanced by a noninvasive electromagnetic field(MF).The affinity constants of D-NPs towardα-syn monomer(mono)orα-syn fibril were 3.5 times or 5.2 times higher,respectively,than those of L-NPs,and the mechanical force generated by NPs under a MF further promoted the interaction between NPs andα-syn to amplify the difference between L-NPs and D-NPs.As the synergy effect of the preferentially affinity ability and MF-induced mechanical forces,D-NPs exhibited a better inhibitory efficiency onα-syn fibrillization than L-NPs.Furthermore,after differentially cellular uptake of L-/D-NPs via the caveolin-mediated pathway,as reactive oxygen species(ROS)-scavengers,D-NPs possess higher efficiency in decreasing intracellular ROS level than L-NPs to provide higher cytoprotective efficiency to neuron cells.In vivo data showed that after treatment with D-NPs under a MF for 60 days,α-syn concentration in the cerebrospinal fluid of PD mice decreased 81%,while dopamine level in the brain of PD mice increased 2.3-fold.These findings indicated the potential of utilizing the synergic interplay of chiral NPs and MF for treating disease and opened a new path to explore the nanoscale chirality for regulating the biological effect.展开更多
Cloud computing plays a significant role in modern information technology, providing organizations with numerous benefits, including flexibility, scalability, and cost-efficiency. However, it has become essential for ...Cloud computing plays a significant role in modern information technology, providing organizations with numerous benefits, including flexibility, scalability, and cost-efficiency. However, it has become essential for organizations to ensure the security of their applications, data, and cloud-based networks to use cloud services effectively. This systematic literature review aims to determine the latest information regarding cloud computing security, with a specific emphasis on threats and mitigation strategies. Additionally, it highlights some common threats related to cloud computing security, such as distributed denial-of-service (DDoS) attacks, account hijacking, malware attacks, and data breaches. This research also explores some mitigation strategies, including security awareness training, vulnerability management, security information and event management (SIEM), identity and access management (IAM), and encryption techniques. It discusses emerging trends in cloud security, such as integrating artificial intelligence (AI) and machine learning (ML), serverless computing, and containerization, as well as the effectiveness of the shared responsibility model and its related challenges. The importance of user awareness and the impact of emerging technologies on cloud security have also been discussed in detail to mitigate security risks. A literature review of previous research and scholarly articles has also been conducted to provide insights regarding cloud computing security. It shows the need for continuous research and innovation to address emerging threats and maintain a security-conscious culture in the company.展开更多
This article signals the use of Artificial Intelligence (AI) in information security where its merits, downsides as well as unanticipated negative outcomes are noted. It considers AI based models that can strengthen o...This article signals the use of Artificial Intelligence (AI) in information security where its merits, downsides as well as unanticipated negative outcomes are noted. It considers AI based models that can strengthen or undermine infrastructural functions and organize the networks. In addition, the essay delves into AI’s role in Cyber security software development and the need for AI-resilient strategies that could anticipate and thwart AI-created vulnerabilities. The document also touched on the socioeconomic ramifications of the emergence of AI in Cyber security as well. Looking into AI and security literature, the report outlines benefits including made threat detection precision, extended security ops efficiency, and preventive security tasks. At the same time, it emphasizes the positive side of AI, but it also shows potential limitations such as data bias, lack of interpretability, ethical concerns, and security flaws. The work similarly focuses on the characterized of misuse and sophisticated cyberattacks. The research suggests ways to diminish AI-generating maleficence which comprise ethical AI development, robust safety measures and constant audits and updates. With regard to the AI application in Cyber security, there are both pros and cons in terms of socio-economic issues, for example, job displacement, economic growth and the change in the required workforce skills.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.62275235).
文摘A numerical model based on measured fictive temperature distributions is explored to evaluate the residual stress fields of CO_(2)laser-annealed mitigated fused silica damage sites.The proposed model extracts the residual strain from the differences in thermoelastic contraction of fused silica with different fictive temperatures from the initial frozen-in temperatures to ambient temperature.The residual stress fields of mitigated damage sites for the CO_(2)laser-annealed case are obtained by a finite element analysis of equilibrium equations and constitutive equations.The simulated results indicate that the proposed model can accurately evaluate the residual stress fields of laser-annealed mitigated damage sites with a complex thermal history.The calculated maximum hoop stress is in good agreement with the reported experimental result.The estimated optical retardance profiles from the calculated radial and hoop stress fields are consistent with the photoelastic measurements.These results provide sufficient evidence to demonstrate the suitability of the proposed model for describing the residual stresses of mitigated fused silica damage sites after CO_(2)laser annealing.
文摘As Egyptian oil and gas downstream information technology has grown digitally over the past decade, security breaches against these digitally connected systems have also increased. These cyber security threats could have devastating effects on the operations and reputation of these companies. Preventing such cyberattacks is crucial. Especially, with the significance of the Egyptian oil and gas downstream sector to the local economy and the fact that many of these connected systems are sometimes managed remotely. This paper examines the value of the ISO 27001 standard in mitigating the effect of cyber threat and seeks to inspire decision-makers to the importance of the proactive measures to strengthen their organization’s cybersecurity posture and protect information critical assets. The study stresses the importance of improving the local educational system to bridge the gap between supply and demand for cybersecurity specialists by implementing a structured approach that emphasizes behavior modification to get a high return on investment in cybersecurity awareness.
基金supported by grants from National Natural Science Foundation of China[81520108001,81700043]the 973 Key Scheme of China[2015CB553406]+2 种基金Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(2014,W Lu)Guangzhou Department of Education for Innovative Team[13C08]Guangdong Natural Science Foundation[2016A030313593]
基金This study was funded by the Quebec Ministry of Forests,Wildlife,and Parks(contrats de service de recherche forestier 142332156-2018-A and 142332174-E:PI:E.Thiffault)by the Natural Science and Engineering Research Council through a Discovery Grant to E.Thiffault(grant number RGPIN-2018-05755).
文摘Background:Forest based climate mitigation emerged as a key component of the Paris Agreement,and thus re-quires robust science to reduce uncertainties related to such strategies.The aim of this study was to assess and compare the cumulative effects on carbon dynamics of forest management and climate change on boreal and northern temperate forest sector in eastern Canada for the 2020–2100 period.Methods:We used the spatially explicit forest landscape model LANDIS-II and its extension Forest Carbon Suc-cession,in conjunction with the Carbon Budget Model for Harvested Wood Products framework.We simulated the dynamics of forest composition and carbon flows from forest ecosystems to wood products and their substitution effect on markets under increasing climate forcing,according to a tonne-year approach.Simulations were con-ducted for a series of forest management scenarios based on realistic practices principally by clearcut in the boreal territory and continuous-cover forestry in the northern temperate one.These scenarios included:i)a business-as-usual scenario(BaU),representing the current management strategy,ii)increased harvesting by 6.3%to 13.9%,iii)increased conservation(i.e.reduced harvesting by 11.1%to 49.8%),iiii)and a scenario representing the natural evolution of the forest landscape(i.e.without any management activity).Results:Our study revealed that increasing harvesting levels had contrasting effects on the mitigation potential in northern temperate(enhance net sequestration)and boreal forest sector(enhance net emissions)in comparison to the BaU from 2040 onwards,regardless of the future climate.Carbon storage in wood products and the substi-tution effect were not sufficient to offset carbon emissions from ecosystems.Moreover,climate change had a strong impact on the capacity of both landscapes to act as carbon sinks.Northern temperate landscapes became a net source of carbon over time due to their greater vulnerability to climate change than boreal landscapes.Conclusions:Our study highlights the need to consider the initial landscape characteristics in simulations to maximize the mitigation potential of alternative forest management strategies.The optimal management solution can be very different according to the characteristics of forest ecosystems.This opens the possibility of optimizing management for specific forest stands,with the objective of maximizing the mitigation potential of a given landscape.
基金This work was supported by a Start-up grant from CTAHR University of Hawaii at Manoa,and USDA Multistate(2052R)to B.M.Apart from providing funds,these organizations were not involved in any experimental procedure and manuscript preparation.
文摘Background:Heat stress is a significant problem in the poultry industry,causing a severe economic loss due to its detrimental effects on chickens’health and performance.Dried plum(DP)is a good source of minerals,vitamins,antioxidants,and phenolic compounds.Studies have suggested that DP has several health benefits,such as maintaining the body’s redox system,immune status,and calcium hemostasis.Based on the health benefits of DP,we hypothesized that the dietary supplementation of DP would alleviate the detrimental effects of heat stress on broiler chickens.Results:To test the hypothesis,day-old broiler chicks(n=72)were randomly allocated to three treatment groups(n=24/group):no heat stress(NHS),heat stress(HS),and heat stress with dried plum(HS+DP),and reared under standard conditions.The inclusion of 2.5%DP in the feed of the HS+DP group was made during the treatment period,while birds in other groups were provided with a standard finisher diet.After 21 days,birds in the HS and HS+DP groups were exposed to cyclic heat stress conditions(33℃ for 8 h during daytime)for 3 weeks,while those in the NHS group were reared under normal conditions(22-24℃).Weekly body weight and feed intake were recorded to calculate the average daily gain(ADG),average daily feed intake(ADFI),and feed conversion ratio(FCR).Heat stress significantly decreased the final body weight,ADG,ADFI,and increased FCR compared to the NHS group,whereas dietary supplementation of DP significantly improved these growth performance parameters compared to the HS group.Furthermore,supplementation of DP significantly increased the expression of heat shock protein-related genes(HSF1,HSF3,HSP70,and HSP90),antioxidant-related genes(SOD1,SOD2,GPX1,GPX3,PRDX1,and TXN),tight junction-related genes(CLDN1,and OCLN),and immune-related genes(IL4,MUC2)in the ileum as compared to the HS group.The microbiota analysis showed significant enrichment of Bacillales,Christensenellaceae,Bacillaceae,Peptostreptococcaceae,and Anaerotruncus in heat-stressed birds supplemented with DP as compared to the HS group.Further,DP supplementation also significantly increased the concentration of acetate,propionate,and total VFA in the cecal digesta of the HS+DP group as compared to the HS group.Conclusion:These findings suggest that DP supplementation effectively improved the growth performances and gut health parameters in the heat-stressed birds.Thus,dried plum can be a potential feed supplement to mitigate heat stress in broiler chickens.
基金funded by the Researchers Supporting Project No.(RSP-2021/390),King Saud University,Riyadh,Saudi Arabia.
文摘In soil biota,higher and enduring concentration of heavy metals like cadmium(Cd)is hazardous and associated with great loss in growth,yield,and quality parameters of most of the crop plants.Recently,in-situ applications of eco-friendly stabilizing agents in the form of organic modifications have been utilized to mitigate the adverse effects of Cd-toxicity.This controlled experiment was laid down to appraise the imprints of various applied organic amendments namely poultry manure(PM),farmyard manure(FYM),and sugarcane press mud(PS)to immobilize Cd in polluted soil.Moreover,phytoavailability of Cd in wheat was also accessed under an alkaline environment.Results revealed that the addition of FYM(5–10 ton ha^(-1))in Cd-contaminated soil significantly increased germination rate,leaf chlorophyll content,plant height,spike length,biological and grain yield amongst all applied organic amendments.Moreover,the addition of FYM(5–10 ton ha^(-1))also reduced the phytoavailability of Cd by 73–85%in the roots,57–83%in the shoots,and 81–90%in grains of wheat crop.Thus,it is affirmed that incorporation of FYM(5–10 ton ha^(-1))performed better to enhance wheat growth and yield by remediating Cd.Thus,the application of FYM(5–10 ton ha^(-1))reduced the toxicity induced by Cd to plants by declining its uptake and translocation as compared to all other applied organic amendments to immobilize Cd under sandy alkaline polluted soil.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12035019,11690041,and 62004221)。
文摘Three-dimensional(3 D)TCAD simulations demonstrate that reducing the distance between the well boundary and N-channel metal-oxide semiconductor(NMOS)transistor or P-channel metal-oxide semiconductor(PMOS)transistor can mitigate the cross section of single event upset(SEU)in 14-nm complementary metal-oxide semiconductor(CMOS)bulk Fin FET technology.The competition of charge collection between well boundary and sensitive nodes,the enhanced restoring currents and the change of bipolar effect are responsible for the decrease of SEU cross section.Unlike dualinterlock cell(DICE)design,this approach is more effective under heavy ion irradiation of higher LET,in the presence of enough taps to ensure the rapid recovery of well potential.Besides,the feasibility of this method and its effectiveness with feature size scaling down are discussed.
文摘With the surge of human population, the need for transportation of goods and people also concomitantly increases, resulting in urban air pollution through emission from motorized traffic especially in developing countries. The extent of environmental pollution in an urban setting is significantly influenced by the pollutants of vehicular fuel combustion. Many effective measures are required in cities to sequester carbon thereby helping to reduce automobile pollution. Roadside greeneries can serve as ecological elements which reduce the concentration of pollutants from vehicular emissions by their direct involvement in absorbing vehicular emitted carbon. In this context, in this study an attempt has been taken to assess contribution of roadside greeneries in absorbing vehicular carbon dioxide emission. A case study has been conducted on arterial roads of mega city Dhaka to quantify the vehicular carbon emission and correlate it with roadside trees to absorb the emitted carbon dioxide. It is noted that in Dhaka city, carbon dioxide is accounted for more than ninety percent of air pollution. To achieve our goals, two busiest arterial roads (namely Mirpur Road and Rokeya Shoroni Road) were taken into account to quantify vehicular carbon emission as well as assess carbon absorption by roadside greeneries. Carbon absorption by different sizes of trees has been quantified using the amount of woody biomass. In addition, absorption by grass-shrubs-herbs has been quantified by the area they cover. The results thus obtained show that indeed the road with more side greeneries absorbs more vehicular emitted carbon dioxide. It is therefore evident that plantation of more roadside trees is an effective measure of reducing air pollution and consequently turning a city to become healthier and more suitable for living.
基金funded by National Key R&D Program of China(2022YFA1304201)National Natural Science Foundation of China(32102573).
文摘Within the agricultural sector,animal production contributes to 14.5%of global anthropogenic greenhouse gas emissions and produces around 37%of global CH_(4) emissions,mainly due to ruminal fermentation in ruminants.Over 90%of CH_(4) is synthesized by methanogens in the rumen during carbohydrate fermentation.According to different substrates,methanogenesis pathways can be divided into four categories:(1)hydrogenotrophic pathway;(2)acetoclastic pathway;(3)methyl dismutation pathway;and(4)methylreducing pathway.Based on the principle of biochemical reactions in the methanogenesis pathways,this paper reviews the latest publications on CH_(4) decreases in ruminants and described three nutritional strategies in terms of dietary nutrient manipulation(feeding management,feed composition,forage quality and lipids),microbial manipulation(ionophore,defaunation,methanogen inhibitors and probiotics),and chemical manipulation(nitrate,organic acids,plant secondary metabolites and phlorotannins,or halides in seaweeds).For each mitigation strategy,the review discusses effectiveness for decreasing CH_(4) emissions,application prescription,and feed safety based on results from in vitro and in vivo studies.This review summarizes different nutritional strategies to mitigate CH_(4) emissions and proposed comprehensive approaches for future feeding interventions and applications in the livestock industry.
基金supported by the Incheon National University Research Grant in 2022,Incheon,Republic of Korea.
文摘With the surge of demand for instant high power in miniaturized electronic and mechanical systems,supercapacitors(SCs)are considered as one of the viable candidates to fulfill the requirements.Thus,long-term resilience and superior energy density associated with self-discharge in SCs are obviously critical,but securing electrode materials,which can meet both benefits of SCs and persist charged potential for a comparatively prolonged duration,are still elusive.Herein,hierarchically refined nickel-sulfide heterostructure(CuO-NS)on CuO(CO)scaffold is achieved through optimized film formation,exhibiting a threefold improvement in the essential electrochemical characteristics and outstanding capacitance retention(∼5%loss).Self-discharge behavior and its mechanism are systematically investigated via morphological control and nanostructural evolution.Furthermore,significant mitigation of self-discharge owing to an increase in surface area and refined nanostructure is displayed.Remarkably,CuO-NS2(20 cycle overcoating)based SC can retain over 60%of the charged potential for a complete voltage holding and a self-discharge test for 16 h.An appealing demonstration of wireless power transmission in burst mode is demonstrated for secure digital(SD)card data writing,powered by SCs,which substantiates that it can be readily leveraged in power management systems.This enables us to realize one of the envisioned applications soon.
基金funded by Blue Ocean Barns.AB has a Ramón y Cajal research contract(RYC2019-027764-I)funded by the Spanish State Research Agency(AEI)。
文摘Background The red macroalgae Asparagopsis is an effective methanogenesis inhibitor due to the presence of halogenated methane(CH_(4))analogues,primarily bromoform(CHBr_(3)).This study aimed to investigate the degradation process of CHBr3 from A taxiformis in the rumen and whether this process is diet-dependent.An in vitro batch culture system was used according to a 2×2 factorial design,assessing two A taxiformis inclusion rates[0(CTL)and 2%DM diet(AT)]and two diets[high-concentrate(HC)and high-forage diet(HF)].Incubations lasted for 72 h and samples of headspace and fermentation liquid were taken at 0,0.5,1,3,6,8,12,16,24,48 and 72 h to assess the pattern of degradation of CHBr_(3) into dibromomethane(CH_(2)Br_(2))and fermentation parameters.Additionally,an in vitro experiment with pure cultures of seven methanogens strains(Methanobrevibacter smithii,Methanobrevibacter ruminantium,Methanosphaera stadtmanae,Methanosarcina barkeri,Methanobrevibacter millerae,Methanorhermobacter wolfei and Methanobacterium mobile)was conducted to test the effects of increasing concentrations of CHBr3(0.4,2,10and 50μmol/L).Results The addition of AT significantly decreased CH_(4) production(P=0.002)and the acetate:propionate ratio(P=0.003)during a 72-h incubation.The concentrations of CHBr_(3) showed a rapid decrease with nearly 90%degraded within the first 3 h of incubation.On the contrary,CH_(2)Br_(2) concentration quickly increased during the first 6 h and then gradually decreased towards the end of the incubation.Neither CHBr_(3) degradation nor CH_(2)Br_(2) synthesis were affected by the type of diet used as substrate,suggesting that the fermentation rate is not a driving factor involved in CHBr_(3)degradation.The in vitro culture of methanogens showed a dose-response effect of CHBr3 by inhibiting the growth of M.smithii,M.ruminantium,M.stadtmanae,M.barkeri,M.millerae,M.wolfei,and M.mobile.Conclusions The present work demonstrated that CHBr_(3) from A.taxiformis is quickly degraded to CH_(2)Br_(2)in the rumen and that the fermentation rate promoted by different diets is not a driving factor involved in CHBr_(3)degradation.
基金supported by the National Natural Science Foundation of China(Grant Nos.12221002,12102233)。
文摘In recent years,explosion shock wave has been considered as a signature injury of the current military conflicts.Although strong shock wave is lethal to the human body,weak shock wave can cause many more lasting consequences.To investigate the protection ability and characteristics of flexible materials and structures under weak shock wave loading,the blast wave produced by TNT explosive is loaded on the polyurethane foam with the density of 200.0 kg/m3(F-200)and 400.0 kg/m3(F-400),polyurea with the density of 1100.0 kg/m^(3)(P-1100)and structures composed of the two materials,which are intended for individual protection.Experimental results indicate that the shock wave is attenuated to weak pressure disturbance after interacting with the flexible materials which are not damaged.The shock wave protective capability of single-layer materials is dependent on their thickness,density and microscopic characteristics.The overpressure,maximum pressure rise rate and impulse of transmitted wave decrease exponentially with increase in sample thickness.For the same thickness,F-400 provides better protective capability than F-200 while P-1100 shows the best protective capability among the three materials.In this study,as the materials are not destroyed,F-200 with a thickness more than10.0 mm,F-400 with a thickness more than 4.0 mm,and P-1100 with a thickness more than 1.0 mm can attenuate the overpressure amplitude more than 90.0%.Further,multi-layer flexible composites are designed.Different layer layouts of designed structures and layer thickness of the single-layer materials can affect the protective performance.Within the research range,the structure in which polyurea is placed on the impact side shows the optimal shock wave protective performance,and the thicknesses of polyurea and polyurethane foam are 1.0 mm and 4.0 mm respectively.The overpressure attenuation rate reached maximum value of 93.3%and impulse attenuation capacity of this structure are better than those of single-layer polyurea and polyurethane foam with higher areal density.
文摘An in-house code,CONTHAC-3D,was developed to calculate and analyze thermal-hydraulic phenomena in containments during severe accidents.CONTHAC-3D is a three-dimensional computational fluid dynamics code that can be applied to predict gas flow,diffusion,and steam condensation in a containment during a severe hypothetical accident,as well as to obtain an estimate of the local hydrogen concentration in various zones of the containment.CONTHAC-3D was developed using multiple models to simulate the features of the proprietary systems and equipment of HPR1000 and ACP100,such as the passive cooling system,passive autocatalytic recombiners and the passive air cooling system.To validate CONTHAC-3D,a GX6 test was performed at the Battelle Model Containment facility.The hydrogen concentration and temperature monitored by the GX6 test are accurately predicted by CONTHAC-3D.Subsequently,the hydrogen distribution in the HPR1000 containment during a severe accident was studied.The results show that the hydrogen removal rates calculated using CONTHAC-3D for different types of PARs agree well with the theoretical values,with an error of less than 1%.As the accident progresses,the hydrogen concentration in the lower compartment becomes higher than that in the large space,which implies that the lower compartment has a higher hydrogen risk than the dome and large space at a later stage of the accident.The amount of hydrogen removed by the PARs placed on the floor of the compartment is small;therefore,raising the installation height of these recombiners appropriately is recommended.However,we do not recommend installing all autocatalytic recombiners at high positions.The study findings in regard to the hydrogen distribution in the HPR1000 containment indicate that CONTHAC-3D can be applied to the study of hydrogen risk containment.
基金funded by the National Key R&D Program of China(No.2023YFC3007900)the Young Scientists Fund of the National Natural Science Foundation of China(No.42106204)+2 种基金the Jiangsu Basic Research Program(Natural Science Foundation)(No.BK20220082)the National Natural Science Foundation of China(No.52271271)the Major Science&Technology Projects of the Ministry of Water Resources(No.SKS-2022025).
文摘This paper provides a comprehensive overview on coastal protection and hazard mitigation by mangroves.Previous stud-ies have made great strides to understand the mechanisms and influencing factors of mangroves’protection function,including wave energy dissipation,storm surge damping,tsunami mitigation,adjustment to sea level rise and wind speed reduction,which are sys-tematically summarized in this study.Moreover,the study analyzes the extensive physical models,based on indoor flume experi-ments and numerical models,that consider the interaction between mangroves and hydrodynamics,to help our understanding of mangrove-hydrodynamic interactions.Additionally,quantitative approaches for valuing coastal protection services provided by man-groves,including index-based and process-resolving approaches,are introduced in detail.Finally,we point out the limitations of previous studies,indicating that efforts are still required for obtaining more long-term field observations during extreme weather events,to create more real mangrove models for physical experiments,and to develop numerical models that consider the flexible properties of mangroves to better predict wave propagation in mangroves having complex morphology and structures.
基金This work was supported financially by the National Natural Science Foundation of China(No.12375176).
文摘The phenomenology involved in severe accidents in nuclear reactors is highly complex.Currently,integrated analysis programs used for severe accident analysis heavily rely on custom empirical parameters,which introduce considerable uncertainty.Therefore,in recent years,the field of severe accidents has shifted its focus toward applying uncertainty analysis methods to quantify uncertainty in safety assessment programs,known as“best estimate plus uncertainty(BEPU).”This approach aids in enhancing our comprehension of these programs and their further development and improvement.This study concentrates on a third-generation pressurized water reactor equipped with advanced active and passive mitigation strategies.Through an Integrated Severe Accident Analysis Program(ISAA),numerical modeling and uncertainty analysis were conducted on severe accidents resulting from large break loss of coolant accidents.Seventeen uncertainty parameters of the ISAA program were meticulously screened.Using Wilks'formula,the developed uncertainty program code,SAUP,was employed to carry out Latin hypercube sampling,while ISAA was employed to execute batch calculations.Statistical analysis was then conducted on two figures of merit,namely hydrogen generation and the release of fission products within the pressure vessel.Uncertainty calculations revealed that hydrogen production and the fraction of fission product released exhibited a normal distribution,ranging from 182.784 to 330.664 kg and from 15.6 to 84.3%,respectively.The ratio of hydrogen production to reactor thermal power fell within the range of 0.0578–0.105.A sensitivity analysis was performed for uncertain input parameters,revealing significant correlations between the failure temperature of the cladding oxide layer,maximum melt flow rate,size of the particulate debris,and porosity of the debris with both hydrogen generation and the release of fission products.
基金Supported by National Natural Science Foundation of China(Grant Nos.U2268210,52302474,52072249).
文摘Wheel polygonal wear can immensely worsen wheel/rail interactions and vibration performances of the train and track,and ultimately,lead to the shortening of service life of railway components.At present,wheel/rail medium-or high-frequency frictional interactions are perceived as an essential reason of the high-order polygonal wear of railway wheels,which are potentially resulted by the flexible deformations of the train/track system or other external excitations.In this work,the effect of wheel/rail flexibility on polygonal wear evolution of heavy-haul locomotive wheels is explored with aid of the long-term wheel polygonal wear evolution simulations,in which different flexible modeling of the heavy-haul wheel/rail coupled system is implemented.Further,the mitigation measures for the polygonal wear of heavy-haul locomotive wheels are discussed.The results point out that the evolution of polygonal wear of heavy-haul locomotive wheels can be veritably simulated with consideration of the flexible effect of both wheelset and rails.Execution of mixed-line operation of heavy-haul trains and application of multicut wheel re-profiling can effectively reduce the development of wheel polygonal wear.This research can provide a deep-going understanding of polygonal wear evolution mechanism of heavy-haul locomotive wheels and its mitigation measures.
基金supported in part by the National Natural Science Foundation of China (No.62271253,61901523,62001381)Fundamental Research Funds for the Central Universities (No.NS2023018)+2 种基金the National Aerospace Science Foundation of China under Grant 2023Z021052002the open research fund of National Mobile Communications Research Laboratory,Southeast University (No.2023D09)Postgraduate Research & Practice Innovation Program of NUAA (No.xcxjh20220402)。
文摘To improve the anti-jamming and interference mitigation ability of the UAV-aided communication systems, this paper investigates the channel selection optimization problem in face of both internal mutual interference and external malicious jamming. A cooperative anti-jamming and interference mitigation method based on local altruistic is proposed to optimize UAVs’ channel selection. Specifically, a Stackelberg game is modeled to formulate the confrontation relationship between UAVs and the jammer. A local altruistic game is modeled with each UAV considering the utilities of both itself and other UAVs. A distributed cooperative anti-jamming and interference mitigation algorithm is proposed to obtain the Stackelberg equilibrium. Finally, the convergence of the proposed algorithm and the impact of the transmission power on the system loss value are analyzed, and the anti-jamming performance of the proposed algorithm can be improved by around 64% compared with the existing algorithms.
基金supported by the National Natural Science Foundation of China (32071400,51902136)
文摘The misfolding and aggregation ofα-synuclein(α-syn)is closely associated with Parkinson’s disease(PD).Here,chiral dimanganese trioxide(Mn_(2)O_(3))nanoparticles(NPs)were prepared for PD treatment enhanced by a noninvasive electromagnetic field(MF).The affinity constants of D-NPs towardα-syn monomer(mono)orα-syn fibril were 3.5 times or 5.2 times higher,respectively,than those of L-NPs,and the mechanical force generated by NPs under a MF further promoted the interaction between NPs andα-syn to amplify the difference between L-NPs and D-NPs.As the synergy effect of the preferentially affinity ability and MF-induced mechanical forces,D-NPs exhibited a better inhibitory efficiency onα-syn fibrillization than L-NPs.Furthermore,after differentially cellular uptake of L-/D-NPs via the caveolin-mediated pathway,as reactive oxygen species(ROS)-scavengers,D-NPs possess higher efficiency in decreasing intracellular ROS level than L-NPs to provide higher cytoprotective efficiency to neuron cells.In vivo data showed that after treatment with D-NPs under a MF for 60 days,α-syn concentration in the cerebrospinal fluid of PD mice decreased 81%,while dopamine level in the brain of PD mice increased 2.3-fold.These findings indicated the potential of utilizing the synergic interplay of chiral NPs and MF for treating disease and opened a new path to explore the nanoscale chirality for regulating the biological effect.
文摘Cloud computing plays a significant role in modern information technology, providing organizations with numerous benefits, including flexibility, scalability, and cost-efficiency. However, it has become essential for organizations to ensure the security of their applications, data, and cloud-based networks to use cloud services effectively. This systematic literature review aims to determine the latest information regarding cloud computing security, with a specific emphasis on threats and mitigation strategies. Additionally, it highlights some common threats related to cloud computing security, such as distributed denial-of-service (DDoS) attacks, account hijacking, malware attacks, and data breaches. This research also explores some mitigation strategies, including security awareness training, vulnerability management, security information and event management (SIEM), identity and access management (IAM), and encryption techniques. It discusses emerging trends in cloud security, such as integrating artificial intelligence (AI) and machine learning (ML), serverless computing, and containerization, as well as the effectiveness of the shared responsibility model and its related challenges. The importance of user awareness and the impact of emerging technologies on cloud security have also been discussed in detail to mitigate security risks. A literature review of previous research and scholarly articles has also been conducted to provide insights regarding cloud computing security. It shows the need for continuous research and innovation to address emerging threats and maintain a security-conscious culture in the company.
文摘This article signals the use of Artificial Intelligence (AI) in information security where its merits, downsides as well as unanticipated negative outcomes are noted. It considers AI based models that can strengthen or undermine infrastructural functions and organize the networks. In addition, the essay delves into AI’s role in Cyber security software development and the need for AI-resilient strategies that could anticipate and thwart AI-created vulnerabilities. The document also touched on the socioeconomic ramifications of the emergence of AI in Cyber security as well. Looking into AI and security literature, the report outlines benefits including made threat detection precision, extended security ops efficiency, and preventive security tasks. At the same time, it emphasizes the positive side of AI, but it also shows potential limitations such as data bias, lack of interpretability, ethical concerns, and security flaws. The work similarly focuses on the characterized of misuse and sophisticated cyberattacks. The research suggests ways to diminish AI-generating maleficence which comprise ethical AI development, robust safety measures and constant audits and updates. With regard to the AI application in Cyber security, there are both pros and cons in terms of socio-economic issues, for example, job displacement, economic growth and the change in the required workforce skills.