Recent researches focused on developing robust blast load mitigation systems due to the threats of terrorist attacks.One of the main embraced strategies is the structural systems that use mitigation techniques.They ar...Recent researches focused on developing robust blast load mitigation systems due to the threats of terrorist attacks.One of the main embraced strategies is the structural systems that use mitigation techniques.They are developed from a combination of structural elements and described herein as conventional systems.Among the promising techniques is that redirect the waves propagation through hollow tubes.The blast wave propagation through tubes provides an efficient system since it combines many blast wave phenomena,such as reflection,diffraction,and interaction.In this research,a novel blast load mitigation system,employed as a protection fence,is developed using a technique similar to the technique of the bent tube in manipulating the shock-wave.The relative performance of the novel system to the conventional system is evaluated based on mitigation percent criteria.Performances of both systems are calculated through numerical simulation.The proposed novel system proved to satisfy high performance in mitigating the generated blast waves from charges weight up to 500 kg TNT at relatively small standoff distances(5 m and 8 m).It mitigates at least 94%of the blast waves,which means that only 6%of that blast impulse is considered as the applied load on the targeted structure.展开更多
Rechargeable alkali metal-sulfur(M-S)batteries,including Li/Na/K-S chemistries,have the potential to utilize abundant and low-cost sulfur cathodes yet offer high theoretical energy densities.However,their practical el...Rechargeable alkali metal-sulfur(M-S)batteries,including Li/Na/K-S chemistries,have the potential to utilize abundant and low-cost sulfur cathodes yet offer high theoretical energy densities.However,their practical electrochemical performance is fundamentally limited by the polysulfide shuttle effect.This challenge is particularly exacerbated in Na-S and K-S systems owing to larger metal-ion radii,weaker solvation energies,slower redox kinetics,and greater electrolyte-electrode incompatibilities compared to Li-S batteries.This review presents a comparative analysis of interface engineering strategies designed to suppress the shuttle effect across these three systems.Following a summary of sulfur cathode properties and reaction mechanisms,we systematically examine the origins of polysulfide shuttling.Our analysis progresses from functional separator design and interlayer enhancements to the implementation of solid-state electrolytes for root-cause inhibition.By evaluating interface engineering research specific to Na-S and K-S batteries,we elucidate both shared principles and unique challenges inherent to alkali M-S systems.Finally,we propose multifaceted solutions to achieve shuttlefree operation and enhance overall battery performance,thereby establishing a foundation for future advancements.展开更多
This study examined the role of green energy development in mitigating climate change and fostering sustainable development in Central Asia including Kazakhstan,Uzbekistan,Kyrgyzstan,Tajikistan,and Turkmenistan.The re...This study examined the role of green energy development in mitigating climate change and fostering sustainable development in Central Asia including Kazakhstan,Uzbekistan,Kyrgyzstan,Tajikistan,and Turkmenistan.The region has substantial untapped potential in solar energy,wind energy,hydropower energy,as well as biomass and bioenergy,positioning it strategically for renewable energy deployment.The result demonstrated that integrating renewable energy can reduce greenhouse gas emissions,improve air quality,enhance energy security,and support rural development.Case studies from Kazakhstan,Uzbekistan,Kyrgyzstan,and Tajikistan showed measurable environmental and economic benefits.However,the large-scale use of renewable energy still faces numerous barriers,including outdated infrastructure,fragmented regulatory frameworks,limited investment,and shortages of technical expertise.Overcoming these obstacles requires institutional reform,stronger regional cooperation,and increasing engagement from international financial institutions and private investors.Modernizing grids,deploying storage systems,and investing in education,research,and innovation are critical for building human capacity in renewable energy sector.Accelerating the renewable energy transition is essential for Central Asia to meet climate goals,enhance environmental resilience,and ensure long-term socioeconomic development through innovation,investment,and regional collaboration.展开更多
In the present study,researchers examined a solar off-grid-connected photovoltaic system for a family house in the city of Baghdad.The design was created with the help of the“How to Design PV Program”and the“Renewa...In the present study,researchers examined a solar off-grid-connected photovoltaic system for a family house in the city of Baghdad.The design was created with the help of the“How to Design PV Program”and the“Renewable Energy Investment Calculator(REICAL)”software(Version 1.1).In Iraq,the national grid provides around 71%of the overall electricity demand,though this drops to nearly 50%during extremely hot and cold months,where the supply alternates between four hours on and four hours off.During the off periods,power is generated by local generators at high costs.To promote the adoption of photovoltaic solar systems among Iraqi citizens through loans,three options for meeting 100% of electricity needs have been proposed:an on-grid solution,a hybrid system that supplies 24 h,and an off-grid solution for a 24-h supply.The 12-h off-grid system(hybrid)is both economical and efficient for delivering electricity.Findings reveal that,over 20 years,the system’s output will amount to 141,176.71 kWh,with a payback period of 5.85 years and a performance ratio of 86.2%.Investment outcome data showed a net present value of $6445,and the profitability index was 6.16,indicating the project’s profitability.Additionally,the system could result in a net reduction of CO_(2) emissions totaling 132,810.24 kg.展开更多
An experimental study on mitigation of greenhouse gas (CH4, N2O and NO) emission has been conducted in a typical cropping system of Southeast China for 4 years. By simultaneous measurement, the CH4, N2O and NO emissio...An experimental study on mitigation of greenhouse gas (CH4, N2O and NO) emission has been conducted in a typical cropping system of Southeast China for 4 years. By simultaneous measurement, the CH4, N2O and NO emission fluxes from rice-wheat rotation fields, effects of fertilization, water management, temperature and soil moisture were investigated. Temperature, fertilization and water status were found to be the key factors to regulate CH4, N2O and NO emis-sions. Based on the experimental results, some agricultural measures were recommended as techni-cal options to mitigate greenhouse gas emissions from rice-wheat rotation ecosystems. These miti-gation measures are reducing mineral N input, coupling organic manure with chemical fertilizers, applying fertilizers which release available N slowly during periods with intensive plant activity, and applying dry fermented organic manure and well management of water and fertilizer. Key words Mitigation options - Emission - Greenhouse gases - Ecosystems This study was supported by projects “ Experimental and Modeling Study on N2O Emission from the Rice-Wheat Rotation Fields of Southeast China” and “ Experimental and Modeling Study on NO Emission from Croplands” , which were granted by the National Natural Science Foundation of China, the State Key Fundamental Research Project “ Predicting the Future (20–50 years) Trend of Environmental Change in China”, and the project of Chinese Academy of Sciences “ Theory and Methodology on Air Pollution Prediction”.Thanks are due to Professor Zhang Wen, Dr. Bai Jianhui, Mr. Gong Yanbang, Mrs. Luo Dongmei and Mr. Liu Guangren from the Institute of Atmospheric Physics, Chinese Academy of Sciences for their help in experiments.展开更多
Taking the complex mechanical systems as the research project,a theoretical multi-degree-of-freedom(MDOF)model was established.Based on the vibration characteristics analysis of this system,a novel method of vibration...Taking the complex mechanical systems as the research project,a theoretical multi-degree-of-freedom(MDOF)model was established.Based on the vibration characteristics analysis of this system,a novel method of vibration mitigation was proposed,which can be applied to most of the complex mechanical systems.Through this method,limited grounding stiffness was made use of and added to certain degree of freedom(DOF)discretely.Thus,the root-meansquare(RMS)of the systems amplitude can be reduced to ideal level.The MATLAB code based on this method was attached,which was tested on the theoretical model.Consider that complex mechanical systems are nonlinear and uncertain,theoretically the optimal solution of vibration mitigation is inaccessible.However,this method can always provide a relatively effective solution.展开更多
Atmospheric turbulence（AT） induced crosstalk can significantly impair the performance of a free-space optical（FSO）communication link using orbital angular momentum（OAM） multiplexing.In this paper,we propose a mu...Atmospheric turbulence（AT） induced crosstalk can significantly impair the performance of a free-space optical（FSO）communication link using orbital angular momentum（OAM） multiplexing.In this paper,we propose a multiple-user detection（MUD） turbulence mitigation scheme in an OAM-multiplexed FSO communication link.First,we present a MUD equivalent communication model for an OAM-multiplexed FSO communication link under AT.In the equivalent model,each input bit stream represents one user＇s information.The deformed OAM spatial modes caused by AT,instead of the pure OAM spatial modes,are used as information carriers,and the overlapping between the deformed OAM spatial modes are computed as the correlation coefficients between the users.Then,we present a turbulence mitigation scheme based on MUD idea to enhance AT tolerance of the OAM-multiplexed FSO communication link.In the proposed scheme,the crosstalk caused by AT is used as a useful component to deduce users＇ information.The numerical results show that the performance of the OAM-multiplexed communication link has greatly improved by the proposed scheme.When the turbulence strength C_n^2 is 1 × 10^（-15） m^（-2/3）,the transmission distance is 1000 m and the channel signal-to-noise ratio（SNR）is 26 dB,the bit-error-rate（BER） performance of four spatial multiplexed OAM modes l_m = ＋ 1,＋2,＋3,＋4 are all close to 10-5,and there is a 2-3 fold increase in the BER performance in comparison with those results without the proposed scheme.In addition,the proposed scheme is more effective for an OAM-multiplexed FSO communication link with a larger OAM mode topological charge interval.The proposed scheme is a promising direction for compensating the interference caused by AT in the OAM-multiplexed FSO communication link.展开更多
In order to meet the demands for high transmission rates and high service quality in broadband wireless communication systems, orthogonal frequency division multiplexing （OFDM） has been adopted in some standards. Ho...In order to meet the demands for high transmission rates and high service quality in broadband wireless communication systems, orthogonal frequency division multiplexing （OFDM） has been adopted in some standards. However, the inter-block interference （IBI） and inter-carrier interference （ICI） in an OFDM system affect the performance. To mitigate IBI and ICI, some pre-processing approaches have been proposed based on full channel state information （CSI）, which improved the system performance. A pre-processing filter based on partial CSI at the transmitter is designed and investigated. The filter coefficient is given by the optimization processing, the symbol error rate （SER） is tested, and the computation complexity of the proposed scheme is analyzed. Computer simulation results show that the proposed pre-processing filter can effectively mitigate IBI and ICI and the performance can be improved. Compared with pre-processing approaches at the transmitter based on full CSI, the proposed scheme has high spectral efficiency, limited CSI feedback and low computation complexity.展开更多
In Orthogonal Frequency Division Multiple Access (OFDMA) systems, such as Long Term Evolution (LTE) and so on, the resources used by each user are orthogonal, and the OFDMA systems performances are mainly affected by ...In Orthogonal Frequency Division Multiple Access (OFDMA) systems, such as Long Term Evolution (LTE) and so on, the resources used by each user are orthogonal, and the OFDMA systems performances are mainly affected by the inter-cell interference. Therefore, the inter-cell interference mitigation technology becomes a hotspot. The objective of interference mitigation technologies used in OFDMA systems are to increase cell-edge throughput and average cell throughput. In this paper, the Resource Block Planning (BRBP) based scheme is proposed to mitigate the inter-cell interference and improve the cell-edge throughput. Comparison between the simulation results of BRBP and Round Robin (RR) illustrates that the enhanced performance of BRBP.展开更多
The Smart Grid is an enhancement of the traditional grid system and employs new technologies and sophisticated communication techniques for electrical power transmission and distribution. The Smart Grid’s communicati...The Smart Grid is an enhancement of the traditional grid system and employs new technologies and sophisticated communication techniques for electrical power transmission and distribution. The Smart Grid’s communication network shares information about status of its several integrated IEDs (Intelligent Electronic Devices). However, the IEDs connected throughout the Smart Grid, open opportunities for attackers to interfere with the communications and utilities resources or take clients’ private data. This development has introduced new cyber-security challenges for the Smart Grid and is a very concerning issue because of emerging cyber-threats and security incidents that have occurred recently all over the world. The purpose of this research is to detect and mitigate Distributed Denial of Service [DDoS] with application to the Electrical Smart Grid System by deploying an optimized Stealthwatch Secure Network analytics tool. In this paper, the DDoS attack in the Smart Grid communication networks was modeled using Stealthwatch tool. The simulated network consisted of Secure Network Analytic tools virtual machines (VMs), electrical Grid network communication topology, attackers and Target VMs. Finally, the experiments and simulations were performed, and the research results showed that Stealthwatch analytic tool is very effective in detecting and mitigating DDoS attacks in the Smart Grid System without causing any blackout or shutdown of any internal systems as compared to other tools such as GNS3, NeSSi2, NISST Framework, OMNeT++, INET Framework, ReaSE, NS2, NS3, M5 Simulator, OPNET, PLC & TIA Portal management Software which do not have the capability to do so. Also, using Stealthwatch tool to create a security baseline for Smart Grid environment, contributes to risk mitigation and sound security hygiene.展开更多
An interference mitigation for acquisition method,based on both energy center and spectrum symmetry detection,has been proposed as a possible solution to the problem of signal acquisition susceptibility to continuous-...An interference mitigation for acquisition method,based on both energy center and spectrum symmetry detection,has been proposed as a possible solution to the problem of signal acquisition susceptibility to continuous-wave interference(CWI)in unified carrier telemetry,tracking,and command(TT&C)systems.With subcarrier modulation index as a priori condition,the existence of CWI is determined by comparing the energy center with the symmetric center.In the presence of interference,the interference frequency point is assumed and culled;sequentially,the spectral symmetry is used to verify whether the signal acquisition is realized.Theoretical analysis,simulations,and experimental results demonstrate that the method can realize the acquisition of the main carrier target signal with an interference-to-signal ratio of 31 dB,which represents an improvement over the existing continuous-wave interference mitigation for acquisition methods.展开更多
Forest carbon monitoring and reporting are critical for informing global climate change assessment. The regional estimates of forest carbon attached greater attention, to assess the role of forest in carbon mitigation...Forest carbon monitoring and reporting are critical for informing global climate change assessment. The regional estimates of forest carbon attached greater attention, to assess the role of forest in carbon mitigation. Here using field inventory, we examined the carbon sink and mitigation potential of monospecific Deodar forest in the Kumrat valley, of Hindu Kush Himalaya, Region of Pakistan, at a different elevation. The elevation of monospecific Deodar forest ranges from 2300 to 2700 m (a.s.l). We divided the forest into three elevation classes (that is 2300 - 2400 m (EI) 2400 - 2500 m (EII) and 2500 - 2700 m (EIII) a.s.l respectively). In each elevation class, we laid out 09 sample plots (33*33 m2) for measuring carbon values in living tree biomass (LT), soil (SC), litter, dead wood, cone (LDWC) and understory vegetation (USV). Our results showed that the carbon density at EI was 432.37 ± 277.96 Mg·C-1, while the carbon density at EII and EIII was 668.35 ± 323.94 and 1016.79 ± 542.99 Mg·C-1 respectively. Our finding revealed that the carbon mitigation potential of the forest increases with increasing elevation. Among the different elevation classes, EIII stored significantly higher carbon due to the dominance of mature, old age, larger trees, and the minimum anthropogenic disturbance, whereas EI stored statistically lower carbon because of maximum anthropogenic disturbance, which resulted in the removal of mature and over-mature trees. Furthermore, our correlation analysis between tree height and carbon stock and basal area and LT carbon, underlines that the basal area is the stronger predictor of LT carbon estimation than height. Overall our results highlight that deodar forest stored 716.94 ± 462.06 Mg?C·ha-1. However, the rehabilitation, preservation and sustainable management of disturb forest located at a lower elevation could considerably improve carbon mitigation potential.展开更多
In this paper, we report the observation and characterisation of a systematic error in the implementation of <em>U</em><sub>3</sub> gates in the IBM quantum computers. By measuring the effect o...In this paper, we report the observation and characterisation of a systematic error in the implementation of <em>U</em><sub>3</sub> gates in the IBM quantum computers. By measuring the effect of this gate for various rotation angles the error appears as an over-rotation, whose magnitude does not correlate with IBM’s cited errors calculated using Clifford randomized benchmarking. We propose a simple mitigation procedure to limit the effects of this error. We show that using a simple mitigation strategy one can obtain improved results in the observed value for the CHSH inequality, measured in a cloud-based quantum computer. This work highlights the utility of simple mitigation strategies for short-depth quantum circuits.展开更多
In this contribution, we use a coupled air quality modelling system (AQM) as a tool to design and develop an air quality plan in Madrid. AQM has allowed us to obtain a preliminary evaluation of the effect of mitigatio...In this contribution, we use a coupled air quality modelling system (AQM) as a tool to design and develop an air quality plan in Madrid. AQM has allowed us to obtain a preliminary evaluation of the effect of mitigation measures over regional and local air quality levels. To achieve these goals, we have prepared a sophisticated AQM, coupling the meteorological model WRF, the emission model AEMM, and the photochemical model CMAQ. AQM was evaluated using the whole modelling year 2010 working with high horizontal resolution, 3 km for the region of Madrid and 1km for urban metropolitan area of Madrid. Two different analyses have been realized: a source apportionment exercise following a zero-out methodology to obtain the contribution to the air quality levels of the different emission sector;and an evaluation of the main mitigation measures considered in the air quality plan using sensitivity analysis. The air quality plan was focused on the improvement of NO<sub>2</sub> levels and AQM analyzed the effect of the mitigation measures during ten episodes of 2011 where NO<sub>2</sub> or O<sub>3</sub> levels were the highest of the year;so we analyzed the effect of the mitigation plan in worst conditions. Results provided by the AQM system show that it accomplishes the European Directive modelling uncertainty requirements and the mean absolute gross error for 1-h maximum daily NO<sub>2</sub> is 31% over locations with higher levels of this atmospheric pollutant;the road traffic is the main contributor to the air quality levels providing a 81% for NO<sub>2</sub>, 67% for CO and 46% for PM<sub>10</sub>;measures defined in the plan achieve to reduce up to 11 μgm<sup>-3</sup> NO<sub>2</sub> levels offering highest reductions over urban areas with traffic influence.展开更多
Due to space constraints in mountainous areas,twin tunnels are sometimes constructed very close to each other or even overlap.This proximity challenges the structural stability of tunnels built with the drill-and-blas...Due to space constraints in mountainous areas,twin tunnels are sometimes constructed very close to each other or even overlap.This proximity challenges the structural stability of tunnels built with the drill-and-blast method,as the short propagation distance amplifies blasting vibrations.A case of blasting damage is reported in this paper,where concrete cracks crossed construction joints in the twin-arch lining.To identify the causes of these cracks and develop effective vibration mitigation measures,field monitoring and numerical analysis were conducted.Specifically,a restart method was used to simulate the second peak particle velocity(PPV)of MS3 delays occurring 50 ms after the MS1 delays.The study found that the dynamic tensile stress in the tunnel induced by the blast wave has a linear relationship with the of the product of the concrete wave impedance and the PPV.A blast vibration velocity exceeding 23.3 cm/s resulted in tensile stress in the lining surpassing the ultimate tensile strength of C30 concrete,leading to tensile cracking on the blast-facing arch of the constructed tunnel.To control excessive vi-bration velocity,a mitigation trench was implemented to reduce blast wave impact.The trench,approximately 15 m in length,50 cm in width,and 450 cm in height,effectively lowered vibration ve-locities,achieving an average reduction rate of 52%according to numerical analysis.A key innovation of this study is the on-site implementation and validation of the trench's effectiveness in mitigating vi-brations.A feasible trench construction configuration was proposed to overcome the limitations of a single trench in fully controlling vibrations.To further enhance protection,zoned blasting and an auxiliary rock pillar,80 cm in width,were incorporated to reinforce the mid-wall.This study introduces novel strategies for vibration protection in tunnel blasting,offering innovative solutions to address blasting-induced vibrations and effectively minimize their impact,thereby enhancing safety and struc-tural stability.展开更多
In the past 80 years, Louisiana has lost over one million acres in land, affecting plants and crustaceans that live in these environments. The first objective of this research was to determine the relationship between...In the past 80 years, Louisiana has lost over one million acres in land, affecting plants and crustaceans that live in these environments. The first objective of this research was to determine the relationship between diffused oxygen in water and time with the behavioral and physiological health of Callinectes sapidus (blue crab) and Procambarus clarkii (crawfish). After 24 hours, manual dexterity, or the amount of time it takes for a crustacean to flip itself over increased under hypoxic conditions. Hemolymph was extracted and tested for lactate, glucose, and protein. Crawfish were also exposed to this same procedure. An additional crawfish study comparing Spartina plants to assimilate oxygen for aeration compared to mechanical aeration was conducted. The hypoxic groups for all three studies at the 0.05 level had a significantly greater manual dexterity time and greater amounts of lactate and glucose. The protein was significantly higher in hypoxia-exposed crawfish. Time and aeration affect the health of crustaceans, and plants were shown to effectively provide normoxic oxygen levels at a similar level as mechanical aeration. These studies support the importance of marsh grasses for the coast and crustacean viability.展开更多
As centers of human activity,cities concentrate populations,resources,and wealth in limited areas.According to the United Nations,55%of the global population now lives in urban areas[1].Moreover,the World Economic Fo...As centers of human activity,cities concentrate populations,resources,and wealth in limited areas.According to the United Nations,55%of the global population now lives in urban areas[1].Moreover,the World Economic Forum’s“Global Risks Report 2023”[2]highlights natural disasters as a major threat to sustainable development,especially for densely populated cities.展开更多
Effective wildland fire management requires real-time access to comprehensive and distilled information from different data sources.The Digital Twin technology becomes a promising tool in optimizing the processes of w...Effective wildland fire management requires real-time access to comprehensive and distilled information from different data sources.The Digital Twin technology becomes a promising tool in optimizing the processes of wildfire pre-vention,monitoring,disaster response,and post-fire recovery.This review examines the potential utility of Digital Twin in wildfire management and aims to inspire further exploration and experimentation by researchers and practitioners in the fields of environment,forestry,fire ecology,and firefighting services.By creating virtual replicas of wildfire in the physical world,a Digital Twin platform facilitates data integration from multiple sources,such as remote sensing,weather forecast-ing,and ground-based sensors,providing a holistic view of emergency response and decision-making.Furthermore,Digital Twin can support simulation-based training and scenario testing for prescribed fire planning and firefighting to improve preparedness and response to evacuation and rescue.Successful applications of Digital Twin in wildfire management require horizontal collaboration among researchers,practitioners,and stakeholders,as well as enhanced resource sharing and data exchange.This review seeks a deeper understanding of future wildland fire management from a technological perspective and inspiration of future research and implementation.Further research should focus on refining and validating Digital Twin models and the integration into existing fire management operations,and then demonstrating them in real wildland fires.展开更多
This paper reviews the development and achievement in the field of satellite system for natural disaster mitigation abroad,analyzes the development trend of the system.The author also makes his views and suggestions o...This paper reviews the development and achievement in the field of satellite system for natural disaster mitigation abroad,analyzes the development trend of the system.The author also makes his views and suggestions on establishing China’s satellite system for natural disaster mitigation here.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
文摘Recent researches focused on developing robust blast load mitigation systems due to the threats of terrorist attacks.One of the main embraced strategies is the structural systems that use mitigation techniques.They are developed from a combination of structural elements and described herein as conventional systems.Among the promising techniques is that redirect the waves propagation through hollow tubes.The blast wave propagation through tubes provides an efficient system since it combines many blast wave phenomena,such as reflection,diffraction,and interaction.In this research,a novel blast load mitigation system,employed as a protection fence,is developed using a technique similar to the technique of the bent tube in manipulating the shock-wave.The relative performance of the novel system to the conventional system is evaluated based on mitigation percent criteria.Performances of both systems are calculated through numerical simulation.The proposed novel system proved to satisfy high performance in mitigating the generated blast waves from charges weight up to 500 kg TNT at relatively small standoff distances(5 m and 8 m).It mitigates at least 94%of the blast waves,which means that only 6%of that blast impulse is considered as the applied load on the targeted structure.
基金supported by the National Natural Science Foundation of China(52371131)the 10th Youth Talent Lifting Project of the China Association for Science and Technology.
文摘Rechargeable alkali metal-sulfur(M-S)batteries,including Li/Na/K-S chemistries,have the potential to utilize abundant and low-cost sulfur cathodes yet offer high theoretical energy densities.However,their practical electrochemical performance is fundamentally limited by the polysulfide shuttle effect.This challenge is particularly exacerbated in Na-S and K-S systems owing to larger metal-ion radii,weaker solvation energies,slower redox kinetics,and greater electrolyte-electrode incompatibilities compared to Li-S batteries.This review presents a comparative analysis of interface engineering strategies designed to suppress the shuttle effect across these three systems.Following a summary of sulfur cathode properties and reaction mechanisms,we systematically examine the origins of polysulfide shuttling.Our analysis progresses from functional separator design and interlayer enhancements to the implementation of solid-state electrolytes for root-cause inhibition.By evaluating interface engineering research specific to Na-S and K-S batteries,we elucidate both shared principles and unique challenges inherent to alkali M-S systems.Finally,we propose multifaceted solutions to achieve shuttlefree operation and enhance overall battery performance,thereby establishing a foundation for future advancements.
文摘This study examined the role of green energy development in mitigating climate change and fostering sustainable development in Central Asia including Kazakhstan,Uzbekistan,Kyrgyzstan,Tajikistan,and Turkmenistan.The region has substantial untapped potential in solar energy,wind energy,hydropower energy,as well as biomass and bioenergy,positioning it strategically for renewable energy deployment.The result demonstrated that integrating renewable energy can reduce greenhouse gas emissions,improve air quality,enhance energy security,and support rural development.Case studies from Kazakhstan,Uzbekistan,Kyrgyzstan,and Tajikistan showed measurable environmental and economic benefits.However,the large-scale use of renewable energy still faces numerous barriers,including outdated infrastructure,fragmented regulatory frameworks,limited investment,and shortages of technical expertise.Overcoming these obstacles requires institutional reform,stronger regional cooperation,and increasing engagement from international financial institutions and private investors.Modernizing grids,deploying storage systems,and investing in education,research,and innovation are critical for building human capacity in renewable energy sector.Accelerating the renewable energy transition is essential for Central Asia to meet climate goals,enhance environmental resilience,and ensure long-term socioeconomic development through innovation,investment,and regional collaboration.
文摘In the present study,researchers examined a solar off-grid-connected photovoltaic system for a family house in the city of Baghdad.The design was created with the help of the“How to Design PV Program”and the“Renewable Energy Investment Calculator(REICAL)”software(Version 1.1).In Iraq,the national grid provides around 71%of the overall electricity demand,though this drops to nearly 50%during extremely hot and cold months,where the supply alternates between four hours on and four hours off.During the off periods,power is generated by local generators at high costs.To promote the adoption of photovoltaic solar systems among Iraqi citizens through loans,three options for meeting 100% of electricity needs have been proposed:an on-grid solution,a hybrid system that supplies 24 h,and an off-grid solution for a 24-h supply.The 12-h off-grid system(hybrid)is both economical and efficient for delivering electricity.Findings reveal that,over 20 years,the system’s output will amount to 141,176.71 kWh,with a payback period of 5.85 years and a performance ratio of 86.2%.Investment outcome data showed a net present value of $6445,and the profitability index was 6.16,indicating the project’s profitability.Additionally,the system could result in a net reduction of CO_(2) emissions totaling 132,810.24 kg.
文摘An experimental study on mitigation of greenhouse gas (CH4, N2O and NO) emission has been conducted in a typical cropping system of Southeast China for 4 years. By simultaneous measurement, the CH4, N2O and NO emission fluxes from rice-wheat rotation fields, effects of fertilization, water management, temperature and soil moisture were investigated. Temperature, fertilization and water status were found to be the key factors to regulate CH4, N2O and NO emis-sions. Based on the experimental results, some agricultural measures were recommended as techni-cal options to mitigate greenhouse gas emissions from rice-wheat rotation ecosystems. These miti-gation measures are reducing mineral N input, coupling organic manure with chemical fertilizers, applying fertilizers which release available N slowly during periods with intensive plant activity, and applying dry fermented organic manure and well management of water and fertilizer. Key words Mitigation options - Emission - Greenhouse gases - Ecosystems This study was supported by projects “ Experimental and Modeling Study on N2O Emission from the Rice-Wheat Rotation Fields of Southeast China” and “ Experimental and Modeling Study on NO Emission from Croplands” , which were granted by the National Natural Science Foundation of China, the State Key Fundamental Research Project “ Predicting the Future (20–50 years) Trend of Environmental Change in China”, and the project of Chinese Academy of Sciences “ Theory and Methodology on Air Pollution Prediction”.Thanks are due to Professor Zhang Wen, Dr. Bai Jianhui, Mr. Gong Yanbang, Mrs. Luo Dongmei and Mr. Liu Guangren from the Institute of Atmospheric Physics, Chinese Academy of Sciences for their help in experiments.
文摘Taking the complex mechanical systems as the research project,a theoretical multi-degree-of-freedom(MDOF)model was established.Based on the vibration characteristics analysis of this system,a novel method of vibration mitigation was proposed,which can be applied to most of the complex mechanical systems.Through this method,limited grounding stiffness was made use of and added to certain degree of freedom(DOF)discretely.Thus,the root-meansquare(RMS)of the systems amplitude can be reduced to ideal level.The MATLAB code based on this method was attached,which was tested on the theoretical model.Consider that complex mechanical systems are nonlinear and uncertain,theoretically the optimal solution of vibration mitigation is inaccessible.However,this method can always provide a relatively effective solution.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61271238 and 61475075)the Open Research Fund of Key Lab of Broadband Wireless Communication and Sensor Network Technology,Ministry of Education,China(Grant No.NYKL2015011)+1 种基金the Postgraduate Innovation Research Plan of Jiangsu Province,China(Grant No.CXZZ13_0489)the University Natural Science Foundation of Jiangsu Province,China(Grant No.16KJB510037)
文摘Atmospheric turbulence（AT） induced crosstalk can significantly impair the performance of a free-space optical（FSO）communication link using orbital angular momentum（OAM） multiplexing.In this paper,we propose a multiple-user detection（MUD） turbulence mitigation scheme in an OAM-multiplexed FSO communication link.First,we present a MUD equivalent communication model for an OAM-multiplexed FSO communication link under AT.In the equivalent model,each input bit stream represents one user＇s information.The deformed OAM spatial modes caused by AT,instead of the pure OAM spatial modes,are used as information carriers,and the overlapping between the deformed OAM spatial modes are computed as the correlation coefficients between the users.Then,we present a turbulence mitigation scheme based on MUD idea to enhance AT tolerance of the OAM-multiplexed FSO communication link.In the proposed scheme,the crosstalk caused by AT is used as a useful component to deduce users＇ information.The numerical results show that the performance of the OAM-multiplexed communication link has greatly improved by the proposed scheme.When the turbulence strength C_n^2 is 1 × 10^（-15） m^（-2/3）,the transmission distance is 1000 m and the channel signal-to-noise ratio（SNR）is 26 dB,the bit-error-rate（BER） performance of four spatial multiplexed OAM modes l_m = ＋ 1,＋2,＋3,＋4 are all close to 10-5,and there is a 2-3 fold increase in the BER performance in comparison with those results without the proposed scheme.In addition,the proposed scheme is more effective for an OAM-multiplexed FSO communication link with a larger OAM mode topological charge interval.The proposed scheme is a promising direction for compensating the interference caused by AT in the OAM-multiplexed FSO communication link.
基金supported by the National Natural Science Foundation of China(60902045)the National High-Tech Research and Developmeent Program of China(863 Program)(2011AA01A105)
文摘In order to meet the demands for high transmission rates and high service quality in broadband wireless communication systems, orthogonal frequency division multiplexing （OFDM） has been adopted in some standards. However, the inter-block interference （IBI） and inter-carrier interference （ICI） in an OFDM system affect the performance. To mitigate IBI and ICI, some pre-processing approaches have been proposed based on full channel state information （CSI）, which improved the system performance. A pre-processing filter based on partial CSI at the transmitter is designed and investigated. The filter coefficient is given by the optimization processing, the symbol error rate （SER） is tested, and the computation complexity of the proposed scheme is analyzed. Computer simulation results show that the proposed pre-processing filter can effectively mitigate IBI and ICI and the performance can be improved. Compared with pre-processing approaches at the transmitter based on full CSI, the proposed scheme has high spectral efficiency, limited CSI feedback and low computation complexity.
文摘In Orthogonal Frequency Division Multiple Access (OFDMA) systems, such as Long Term Evolution (LTE) and so on, the resources used by each user are orthogonal, and the OFDMA systems performances are mainly affected by the inter-cell interference. Therefore, the inter-cell interference mitigation technology becomes a hotspot. The objective of interference mitigation technologies used in OFDMA systems are to increase cell-edge throughput and average cell throughput. In this paper, the Resource Block Planning (BRBP) based scheme is proposed to mitigate the inter-cell interference and improve the cell-edge throughput. Comparison between the simulation results of BRBP and Round Robin (RR) illustrates that the enhanced performance of BRBP.
文摘The Smart Grid is an enhancement of the traditional grid system and employs new technologies and sophisticated communication techniques for electrical power transmission and distribution. The Smart Grid’s communication network shares information about status of its several integrated IEDs (Intelligent Electronic Devices). However, the IEDs connected throughout the Smart Grid, open opportunities for attackers to interfere with the communications and utilities resources or take clients’ private data. This development has introduced new cyber-security challenges for the Smart Grid and is a very concerning issue because of emerging cyber-threats and security incidents that have occurred recently all over the world. The purpose of this research is to detect and mitigate Distributed Denial of Service [DDoS] with application to the Electrical Smart Grid System by deploying an optimized Stealthwatch Secure Network analytics tool. In this paper, the DDoS attack in the Smart Grid communication networks was modeled using Stealthwatch tool. The simulated network consisted of Secure Network Analytic tools virtual machines (VMs), electrical Grid network communication topology, attackers and Target VMs. Finally, the experiments and simulations were performed, and the research results showed that Stealthwatch analytic tool is very effective in detecting and mitigating DDoS attacks in the Smart Grid System without causing any blackout or shutdown of any internal systems as compared to other tools such as GNS3, NeSSi2, NISST Framework, OMNeT++, INET Framework, ReaSE, NS2, NS3, M5 Simulator, OPNET, PLC & TIA Portal management Software which do not have the capability to do so. Also, using Stealthwatch tool to create a security baseline for Smart Grid environment, contributes to risk mitigation and sound security hygiene.
基金Supported by the National Natural Science Foundation of China(61401026)
文摘An interference mitigation for acquisition method,based on both energy center and spectrum symmetry detection,has been proposed as a possible solution to the problem of signal acquisition susceptibility to continuous-wave interference(CWI)in unified carrier telemetry,tracking,and command(TT&C)systems.With subcarrier modulation index as a priori condition,the existence of CWI is determined by comparing the energy center with the symmetric center.In the presence of interference,the interference frequency point is assumed and culled;sequentially,the spectral symmetry is used to verify whether the signal acquisition is realized.Theoretical analysis,simulations,and experimental results demonstrate that the method can realize the acquisition of the main carrier target signal with an interference-to-signal ratio of 31 dB,which represents an improvement over the existing continuous-wave interference mitigation for acquisition methods.
文摘Forest carbon monitoring and reporting are critical for informing global climate change assessment. The regional estimates of forest carbon attached greater attention, to assess the role of forest in carbon mitigation. Here using field inventory, we examined the carbon sink and mitigation potential of monospecific Deodar forest in the Kumrat valley, of Hindu Kush Himalaya, Region of Pakistan, at a different elevation. The elevation of monospecific Deodar forest ranges from 2300 to 2700 m (a.s.l). We divided the forest into three elevation classes (that is 2300 - 2400 m (EI) 2400 - 2500 m (EII) and 2500 - 2700 m (EIII) a.s.l respectively). In each elevation class, we laid out 09 sample plots (33*33 m2) for measuring carbon values in living tree biomass (LT), soil (SC), litter, dead wood, cone (LDWC) and understory vegetation (USV). Our results showed that the carbon density at EI was 432.37 ± 277.96 Mg·C-1, while the carbon density at EII and EIII was 668.35 ± 323.94 and 1016.79 ± 542.99 Mg·C-1 respectively. Our finding revealed that the carbon mitigation potential of the forest increases with increasing elevation. Among the different elevation classes, EIII stored significantly higher carbon due to the dominance of mature, old age, larger trees, and the minimum anthropogenic disturbance, whereas EI stored statistically lower carbon because of maximum anthropogenic disturbance, which resulted in the removal of mature and over-mature trees. Furthermore, our correlation analysis between tree height and carbon stock and basal area and LT carbon, underlines that the basal area is the stronger predictor of LT carbon estimation than height. Overall our results highlight that deodar forest stored 716.94 ± 462.06 Mg?C·ha-1. However, the rehabilitation, preservation and sustainable management of disturb forest located at a lower elevation could considerably improve carbon mitigation potential.
文摘In this paper, we report the observation and characterisation of a systematic error in the implementation of <em>U</em><sub>3</sub> gates in the IBM quantum computers. By measuring the effect of this gate for various rotation angles the error appears as an over-rotation, whose magnitude does not correlate with IBM’s cited errors calculated using Clifford randomized benchmarking. We propose a simple mitigation procedure to limit the effects of this error. We show that using a simple mitigation strategy one can obtain improved results in the observed value for the CHSH inequality, measured in a cloud-based quantum computer. This work highlights the utility of simple mitigation strategies for short-depth quantum circuits.
文摘In this contribution, we use a coupled air quality modelling system (AQM) as a tool to design and develop an air quality plan in Madrid. AQM has allowed us to obtain a preliminary evaluation of the effect of mitigation measures over regional and local air quality levels. To achieve these goals, we have prepared a sophisticated AQM, coupling the meteorological model WRF, the emission model AEMM, and the photochemical model CMAQ. AQM was evaluated using the whole modelling year 2010 working with high horizontal resolution, 3 km for the region of Madrid and 1km for urban metropolitan area of Madrid. Two different analyses have been realized: a source apportionment exercise following a zero-out methodology to obtain the contribution to the air quality levels of the different emission sector;and an evaluation of the main mitigation measures considered in the air quality plan using sensitivity analysis. The air quality plan was focused on the improvement of NO<sub>2</sub> levels and AQM analyzed the effect of the mitigation measures during ten episodes of 2011 where NO<sub>2</sub> or O<sub>3</sub> levels were the highest of the year;so we analyzed the effect of the mitigation plan in worst conditions. Results provided by the AQM system show that it accomplishes the European Directive modelling uncertainty requirements and the mean absolute gross error for 1-h maximum daily NO<sub>2</sub> is 31% over locations with higher levels of this atmospheric pollutant;the road traffic is the main contributor to the air quality levels providing a 81% for NO<sub>2</sub>, 67% for CO and 46% for PM<sub>10</sub>;measures defined in the plan achieve to reduce up to 11 μgm<sup>-3</sup> NO<sub>2</sub> levels offering highest reductions over urban areas with traffic influence.
基金supported by the Shenzhen Stability Support Plan(Grant No.20231122095154003)National Natural Science Foundation of China(Grant Nos.51978671 and 52378425)Guizhou Provincial Department of Transportation Science and Technology Program(Grant No.2023-122-003)。
文摘Due to space constraints in mountainous areas,twin tunnels are sometimes constructed very close to each other or even overlap.This proximity challenges the structural stability of tunnels built with the drill-and-blast method,as the short propagation distance amplifies blasting vibrations.A case of blasting damage is reported in this paper,where concrete cracks crossed construction joints in the twin-arch lining.To identify the causes of these cracks and develop effective vibration mitigation measures,field monitoring and numerical analysis were conducted.Specifically,a restart method was used to simulate the second peak particle velocity(PPV)of MS3 delays occurring 50 ms after the MS1 delays.The study found that the dynamic tensile stress in the tunnel induced by the blast wave has a linear relationship with the of the product of the concrete wave impedance and the PPV.A blast vibration velocity exceeding 23.3 cm/s resulted in tensile stress in the lining surpassing the ultimate tensile strength of C30 concrete,leading to tensile cracking on the blast-facing arch of the constructed tunnel.To control excessive vi-bration velocity,a mitigation trench was implemented to reduce blast wave impact.The trench,approximately 15 m in length,50 cm in width,and 450 cm in height,effectively lowered vibration ve-locities,achieving an average reduction rate of 52%according to numerical analysis.A key innovation of this study is the on-site implementation and validation of the trench's effectiveness in mitigating vi-brations.A feasible trench construction configuration was proposed to overcome the limitations of a single trench in fully controlling vibrations.To further enhance protection,zoned blasting and an auxiliary rock pillar,80 cm in width,were incorporated to reinforce the mid-wall.This study introduces novel strategies for vibration protection in tunnel blasting,offering innovative solutions to address blasting-induced vibrations and effectively minimize their impact,thereby enhancing safety and struc-tural stability.
文摘In the past 80 years, Louisiana has lost over one million acres in land, affecting plants and crustaceans that live in these environments. The first objective of this research was to determine the relationship between diffused oxygen in water and time with the behavioral and physiological health of Callinectes sapidus (blue crab) and Procambarus clarkii (crawfish). After 24 hours, manual dexterity, or the amount of time it takes for a crustacean to flip itself over increased under hypoxic conditions. Hemolymph was extracted and tested for lactate, glucose, and protein. Crawfish were also exposed to this same procedure. An additional crawfish study comparing Spartina plants to assimilate oxygen for aeration compared to mechanical aeration was conducted. The hypoxic groups for all three studies at the 0.05 level had a significantly greater manual dexterity time and greater amounts of lactate and glucose. The protein was significantly higher in hypoxia-exposed crawfish. Time and aeration affect the health of crustaceans, and plants were shown to effectively provide normoxic oxygen levels at a similar level as mechanical aeration. These studies support the importance of marsh grasses for the coast and crustacean viability.
基金the Ministry of Science and Technology National Key Research and Development Program(2023YFC3805000)the National Natural Science Foundation of China(52025083 and 52208501)the Shanghai Science and Technology Innovation Action Plan(22dz1201400).
文摘As centers of human activity,cities concentrate populations,resources,and wealth in limited areas.According to the United Nations,55%of the global population now lives in urban areas[1].Moreover,the World Economic Forum’s“Global Risks Report 2023”[2]highlights natural disasters as a major threat to sustainable development,especially for densely populated cities.
基金funded by the National Natural Science Foundation of China(NSFC No.52322610)Hong Kong Research Grants Council Theme-based Research Scheme(T22-505/19-N).
文摘Effective wildland fire management requires real-time access to comprehensive and distilled information from different data sources.The Digital Twin technology becomes a promising tool in optimizing the processes of wildfire pre-vention,monitoring,disaster response,and post-fire recovery.This review examines the potential utility of Digital Twin in wildfire management and aims to inspire further exploration and experimentation by researchers and practitioners in the fields of environment,forestry,fire ecology,and firefighting services.By creating virtual replicas of wildfire in the physical world,a Digital Twin platform facilitates data integration from multiple sources,such as remote sensing,weather forecast-ing,and ground-based sensors,providing a holistic view of emergency response and decision-making.Furthermore,Digital Twin can support simulation-based training and scenario testing for prescribed fire planning and firefighting to improve preparedness and response to evacuation and rescue.Successful applications of Digital Twin in wildfire management require horizontal collaboration among researchers,practitioners,and stakeholders,as well as enhanced resource sharing and data exchange.This review seeks a deeper understanding of future wildland fire management from a technological perspective and inspiration of future research and implementation.Further research should focus on refining and validating Digital Twin models and the integration into existing fire management operations,and then demonstrating them in real wildland fires.
文摘This paper reviews the development and achievement in the field of satellite system for natural disaster mitigation abroad,analyzes the development trend of the system.The author also makes his views and suggestions on establishing China’s satellite system for natural disaster mitigation here.
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.
