Advanced oxidation processes have been widely studied for organic pollutants treatment in water,but the degradation performance of radical-dominated pathway was severely inhibited by the side reactions between the ani...Advanced oxidation processes have been widely studied for organic pollutants treatment in water,but the degradation performance of radical-dominated pathway was severely inhibited by the side reactions between the anions and radicals,especially in high salinity conditions.Here,a singlet oxygen(^(1)O_(2))-dominated non-radical process was developed for organic pollutants degradation in high salinity wastewater,with layered crednerite(CuMnO_(2))as catalysts and peroxymonosulfate(PMS)as oxidant.Based on the experiments and density functional theory calculations,^(1)O_(2)was the dominating reactive species and the constructed Cu-O-Mn with electron-deficient Mn captured electron from PMS promoting the generation of^(1)O_(2).The rapid degradation of bisphenol A(BPA)was achieved by CuMnO_(2)/PMS system,which was 5-fold and 21-fold higher than that in Mn_(2)O_(3)/PMS system and Cu_(2)O/PMS system.The CuMnO_(2)/PMS system shown prominent BPA removal performance under high salinity conditions,prominent PMS utilization efficiency,outstanding total organic carbon removal rate,wide range of applicable pH and good stability.This work unveiled that the^(1)O_(2)-dominated non-radical process of CuMnO_(2)/PMS system overcame the inhibitory effect of anions in high salinity conditions,which provided a promising technique to remove organic pollutants from high saline wastewater.展开更多
The accurate analysis of the seismic response of isolated structures requires incorporation of the flexibility of supporting soil. However, it is often customary to idealize the soil as rigid during the analysis of su...The accurate analysis of the seismic response of isolated structures requires incorporation of the flexibility of supporting soil. However, it is often customary to idealize the soil as rigid during the analysis of such structures. In this paper, seismic response time history analyses of base-isolated buildings modelled as linear single degree-of-freedom （SDOF） and multi degree-of-freedom （MDOF） systems with linear and nonlinear base models considering and ignoring the flexibility of supporting soil are conducted. The flexibility of supporting soil is modelled through a lumped parameter model consisting of swaying and rocking spring-dashpots. In the analysis, a large number of parametric studies for different earthquake excitations with three different peak ground acceleration （PGA） levels, different natural periods of the building models, and different shear wave velocities in the soil are considered. For the isolation system, laminated rubber bearings （LRBs） as well as high damping rubber bearings （HDRBs） are used. Responses of the isolated buildings with and without SSI are compared under different ground motions leading to the following conclusions： （1） soil flexibility may considerably influence the stiff superstructure response and may only slightly influence the response of the flexible structures; （2） the use of HDRBs for the isolation system induces higher structural peak responses with SSI compared to the system with LRBs; （3） although the peak response is affected by the incorporation of soil flexibility, it appears insensitive to the variation of shear wave velocity in the soil; （4） the response amplifications of the SDOF system become closer to unit with the increase in the natural period of the building, indicating an inverse relationship between SSI effects and natural periods for all the considered ground motions, base isolations and shear wave velocities; （5） the incorporation of SSI increases the number of significant cycles of large amplitude accelerati展开更多
With an extensive range of distinctive features at nano meter-scale thicknesses,two-dimensional(2D)materials drawn the attention of the scientific community.Despite tremendous advancements in exploratory research on 2...With an extensive range of distinctive features at nano meter-scale thicknesses,two-dimensional(2D)materials drawn the attention of the scientific community.Despite tremendous advancements in exploratory research on 2D materials,knowledge of 2D electrical transport and carrier dynamics still in its infancy.Thus,here we highlighted the electrical characteristics of 2D materials with electronic band structure,electronic transport,dielectric constant,carriers mobility.The atomic thinness of 2D materials makes substantially scaled field-effect transistors(FETs)with reduced short-channel effects conceivable,even though strong carrier mobility required for high performance,low-voltage device operations.We also discussed here about factors affecting 2D materials which easily enhanced the activity of those materials for various applications.Presently,Those 2D materials used in state-of-the-art electrical and optoelectronic devices because of the extensive nature of their electronic band structure.2D materials offer unprecedented freedom for the design of novel p-n junction device topologies in contrast to conventional bulk semiconductors.We also,describe the numerous 2D p-n junctions,such as homo junction and hetero junction including mixed dimensional junctions.Finally,we talked about the problems and potential for the future.展开更多
Here,we report the synthesis of hard carbon materials(RH) made from natural rice husk through a single pyrolysis process and their application as an anode in sodium-ion batteries.The studies show that the electrochemi...Here,we report the synthesis of hard carbon materials(RH) made from natural rice husk through a single pyrolysis process and their application as an anode in sodium-ion batteries.The studies show that the electrochemical properties of RHs are affected by the treatment temperatures,which determine the materials morphology,in particular,their degree of graphitization and extent of continuous channels(nanovoids).The latter are accessible to sodium ions and significantly contribute to charge storage capacity of the produced anodes.The RHs obtained at 1600 °C deliver the highest reversible capacity of276 mAh g^(-1) mainly due to insertion of sodium ions into the nanovoids.This work deepens the basic understanding of the influence of the carbonization temperature on the sodium storage mechanism.展开更多
Despite the planned installation and operations of the traditional IEEE 802.11 networks,they still experience degraded performance due to the number of inefficiencies.One of the main reasons is the received signal str...Despite the planned installation and operations of the traditional IEEE 802.11 networks,they still experience degraded performance due to the number of inefficiencies.One of the main reasons is the received signal strength indicator(RSSI)association problem,in which the user remains connected to the access point(AP)unless the RSSI becomes too weak.In this paper,we propose a multi-criterion association(WiMA)scheme based on software defined networking(SDN)in Wi-Fi networks.An association solution based on multi-criterion such as AP load,RSSI,and channel occupancy is proposed to satisfy the quality of service(QoS).SDNhaving an overall view of the network takes the association and reassociation decisions making the handoffs smooth in throughput performance.To implementWiMA extensive simulations runs are carried out on Mininet-NS3-Wi-Fi network simulator.The performance evaluation shows that the WiMA significantly reduces the average number of retransmissions by 5%–30%and enhances the throughput by 20%–50%,hence maintaining user fairness and accommodating more wireless devices and traffic load in the network,when compared to traditional client-driven(CD)approach and state of the art Wi-Balance approach.展开更多
In this study,the effects of soluble readily biodegradable COD(sCOD)and particulate slowly biodegradable COD(pCOD)on anammox process were investigated.The results of the longterm experiment indicated that a low sCOD/N...In this study,the effects of soluble readily biodegradable COD(sCOD)and particulate slowly biodegradable COD(pCOD)on anammox process were investigated.The results of the longterm experiment indicated that a low sCOD/N ratio of 0.5 could accelerate the anammox and denitrification activity,to reach as high as 84.9%±2.8%TN removal efficiency.Partial denitrification-anammox(PDN/anammox)and denitrification were proposed as the major pathways for nitrogen removal,accounting for 91.3% and 8.7% of the TN removal,respectively.Anammox bacteria could remain active with high abundance of anammox genes to maintain its dominance.Candidatus Kuenenia and Thauera were the predominant genera in the presence of organic matter.Compared with sCOD,batch experiments showed that the introduction of pCOD had a negative effect on nitrogen removal.The contribution of denitrification to nitrogen removal decreased from approximately 14%to 3% with increasing percentage of pCOD.In addition,the analysis result of the process data using an optimized ASM1 model indicated that high percentage of pCOD resulted in serious N_(2)O emission(the peak value up to 0.25mg N/L),whichwas likely due to limited mass diffusion and insufficient available carbon sources for denitrification.However,a high sCOD/N ratio was beneficial for alleviating N_(2)O accumulation.展开更多
Understanding the relationship between the properties and performance of black titanium dioxide with core-shell structure(CSBT)for environmental remediation is crucial for improving its prospects in practical applicat...Understanding the relationship between the properties and performance of black titanium dioxide with core-shell structure(CSBT)for environmental remediation is crucial for improving its prospects in practical applications.In this study,CSBT was synthesized using a glycerol-assisted sol-gel approach.The effect of different water-to-glycerol ratios(W:G=1:0,9:1,2:1,and 1:1)on the semiconducting and physicochemical properties of CSBT was investigated.The effectiveness of CSBT in removing phenolic compounds(PHCs)from real agro-industrial wastewater was studied.The CSBT synthesized with a W:G ratio of 9:1 has optimized properties for enhanced removal of PHCs.It has a distinct coreshell structure and an appropriate amount of Ti3+cations(11.18%),which play a crucial role in enhancing the performance of CSBT.When exposed to visible light,the CSBT performed better:48.30%of PHCs were removed after 180 min,compared to only 21.95%for TiO_(2) without core-shell structure.The CSBT consumed only 45.5235 kWh/m^(3) of electrical energy per order of magnitude and cost$2.4127 per unit volume of treated agro-industrial wastewater.Under the conditions tested,the CSBT demonstrated exceptional stability and reusability.The CSBT showed promising results in the treatment of phenols-containing agro-industrial wastewater.展开更多
There are an increasing number of Narrow Band IoT devices being manufactured as the technology behind them develops quickly.The high co‐channel interference and signal attenuation seen in edge Narrow Band IoT devices...There are an increasing number of Narrow Band IoT devices being manufactured as the technology behind them develops quickly.The high co‐channel interference and signal attenuation seen in edge Narrow Band IoT devices make it challenging to guarantee the service quality of these devices.To maximise the data rate fairness of Narrow Band IoT devices,a multi‐dimensional indoor localisation model is devised,consisting of transmission power,data scheduling,and time slot scheduling,based on a network model that employs non‐orthogonal multiple access via a relay.Based on this network model,the optimisation goal of Narrow Band IoT device data rate ratio fairness is first established by the authors,while taking into account the Narrow Band IoT network:The multidimensional indoor localisation optimisation model of equipment tends to minimize data rate,energy constraints and EH relay energy and data buffer constraints,data scheduling and time slot scheduling.As a result,each Narrow Band IoT device's data rate needs are met while the network's overall performance is optimised.We investigate the model's potential for convex optimisation and offer an algorithm for optimising the distribution of multiple resources using the KKT criterion.The current work primarily considers the NOMA Narrow Band IoT network under a single EH relay.However,the growth of Narrow Band IoT devices also leads to a rise in co‐channel interference,which impacts NOMA's performance enhancement.Through simulation,the proposed approach is successfully shown.These improvements have boosted the network's energy efficiency by 44.1%,data rate proportional fairness by 11.9%,and spectrum efficiency by 55.4%.展开更多
This paper analyses the issue of accelerated start-up of a marine steam turbine,which is an important problem because the start-up of a steam machine involves the combustion of fuel that is not transformed into useful...This paper analyses the issue of accelerated start-up of a marine steam turbine,which is an important problem because the start-up of a steam machine involves the combustion of fuel that is not transformed into useful energy.To find novel technologies that offer improvements in this aspect is essential due to restrictions on reducing ship emissions.Thus,the shorter the start-up time,the better for the environment and economy.High-pressure(HP)part of the turbine originally located on the Queen Elizabeth II unit was analysed.Advanced numerical calculations by thermal fluid-solid-interaction(Thermal FSI)were carried out.A series of simulations were performed for the accelerated start-up with controlled steam injection.A description of the chosen calculation methodology and the results obtained by simulation are included in this paper.The stress occurring during the accelerated start-up are approximately 40 MPa higher than those during the reference start-up.The relative elongations between the rotor and the hull during accelerated start-up reach a maximum value of 0.89 mm(0.83 mm for ultra-fast start-up).Reducing the steam turbine start-up time by 75%results in a 36.7 tons reduction in fuel consumption for start-up,resulting in an annual savings of 5372 USD.In conclusion,the concept proposed by the authors is safe,less expensive and does not affect the life of the turbine.In addition,results and applications from Siemens prove that additional injection of cooling steam is possible.展开更多
Solid oxide fuel cells based on doped cefia electrolytes offer operating temperatures of -600℃. During recent years much atten- tion was aimed at successful powder preparation with high sinter activity and high condu...Solid oxide fuel cells based on doped cefia electrolytes offer operating temperatures of -600℃. During recent years much atten- tion was aimed at successful powder preparation with high sinter activity and high conductivity. The properties of ceria electrolyte are very sensitive to impurities introduced during powder and electrolyte fabrication. One of the most successful and commercially available processes for the production of clean powders is based on the addition of several percent metallic cations that will react with impurities and segregate into the triple points of grain boundaries. In this work the results obtained from doping of CGO20 by 2% Ca and prepared by different routes were presented. The way of introducing Ca seemed to play an important role.展开更多
Starting from the classical centrifugal compressor, cone shaped in meridional cross section, two modifications are considered on the basis of results from 2D and 3D flow models. The first modification is the change of...Starting from the classical centrifugal compressor, cone shaped in meridional cross section, two modifications are considered on the basis of results from 2D and 3D flow models. The first modification is the change of the meridional cross section to hyperbolically shaped channel. The second modification, proposed on the basis of 2D axisymmetric solution, concerns the shape of blading. On the strength of this solution the blades are formed as 3D shaped blades, coinciding with the recent tendency in 3D designs. Two aims were considered for the change of meridional compressor shape. The first was to remove the separation zone which appears as the flow turns from axial to radial direction. The second aim is to uniformize the flow at exit of impeller. These two goals were considered within the frame of 2D axisymmetric model. Replacing the cone shaped compressor by a hyperbolically shaped one, the separation at the corner was removed. The disc and shroud shape of the compressor was chosen in the way which satisfies the condition of most uniform flow at the compressor exit. The uniformity of exit flow from the rotor can be considered as the factor which influences the performance of the diffuser following the rotor. In the 2D model a family of stream surfaces of S1 type is given in order to find S2 surfaces which may be identified with the midblade surfaces of compressor blading. A computation of 3D type has been performed in order to establish the relations between 2D and 3D models in the calculation of flow parameters. In the presented example the 2D model appears as the inverse model which leads to 3D shape of blading whereas the 3D model has been used for the direct solution. In the presented example the confrontation of two models, 2D and 3D, leads to a better understanding of the application of these models to the design procedure.展开更多
Electromagnetic simulation and electronic design automation(EDA)play an important role in the design of 5G antennas and radio chips.The simulation challenges include electromagnetic effects and long simulation time an...Electromagnetic simulation and electronic design automation(EDA)play an important role in the design of 5G antennas and radio chips.The simulation challenges include electromagnetic effects and long simulation time and this paper focuses on simulation software based on finite-element method(FEM).The state-of-the-art EDA software using novel computational techniques based on FEM can not only accelerate numerical analysis,but also enable optimization,sensitivity analysis and interactive design tuning based on rigorous electromagnetic model of a device.Several new techniques that help to mitigate the most challenging issues related to FEM based simulation are highlighted.In particular,methods for fast frequency sweep,mesh morphing and surrogate models for efficient optimization and manual design tuning are briefly described,and their efficiency is illustrated on examples involving a 5G multiple-input multiple-output(MIMO)antenna and filter.It is demonstrated that these new computational techniques enable significant reduction of time needed for design closure with the acceleration rates as large as tens or even over one hundred.展开更多
Ordered titanium dioxide nanotubes （TiOaNTs） modified with indium tin oxide （ITO） films were obtained via magnetron sputtering, in which ITO plate was used as a target, onto the as-anodized titania support followe...Ordered titanium dioxide nanotubes （TiOaNTs） modified with indium tin oxide （ITO） films were obtained via magnetron sputtering, in which ITO plate was used as a target, onto the as-anodized titania support followed by the calcination process. The morphology of fabricated material with deposited oxide was investigated using scanning electron microscopy. Raman and UV-Vis spectroscopies were utilized to characterize crystalline phase and optical properties of prepared samples, whereas X-ray photoelectron spectroscopy allowed determining the binding energy of present elements. In the case of titanium, three various oxidation states were identified and also the presence of indium and tin was confirmed. The electrochemical test carried out when the sample was exposed to light allows for selection of the most photoactive material. The highest photocurrent was registered when only 5-nm ITO layer was sputtered, and it equals 256 and 133 μA cm^-2 for the electrode material immersed in 0.5 M KOH and K2SO4 electrolytes, respectively, that is accordingly 3.5 and 4.4 times higher than the one observed for pristine titania. Furthermore, ITO-modified titania exhibits excellent photostability upon prolonged illumination that is of key importance for possible application in light-driven processes.展开更多
Low-head hydraulic turbines are the subjects to individual approach of design. This comes from the fact that hydrological conditions are not of a standard character. Therefore, the design method of the hydraulic turbi...Low-head hydraulic turbines are the subjects to individual approach of design. This comes from the fact that hydrological conditions are not of a standard character. Therefore, the design method of the hydraulic turbine stage has a great importance for those who may be interested in such an investment. As a first task in a design procedure the guide vane is considered. The proposed method is based on the solution of the inverse problem within the flame of 2D model. By the inverse problem authors mean a design of the blade shapes for given flow conditions. In the paper analytical solution for the simple cylindrical shape of a guide vane is presented. For the more realistic cases numerical solutions according to the axis-symmetrical model of the flow are also presented. The influence of such parameters as the inclination of trailing edge, the blockage factor due to blade thickness, the influence of loss due to dissipation are shown for the chosen simple geometrical example.展开更多
Agricultural waste is a still untapped source of materials that can,in case of proper utilization,significantly improve the sustainability of polymers and their composites.In this work,polymer composites based on isot...Agricultural waste is a still untapped source of materials that can,in case of proper utilization,significantly improve the sustainability of polymers and their composites.In this work,polymer composites based on isotactic polypropylene were produced incorporating ground sunflower husk in the amount of 10 wt%and 20 wt%.The work’s main objective is to evaluate how preliminary fractioning of this agricultural waste filler affects the thermomechanical properties,microstructure and surface topology of polypropylene-based injection molded composites.The composites were analyzed for mechanical properties(tensile,impact strength and hardness),thermomechanical properties(Vicat softening point VST,heat deflection temperature HDT,and dynamic thermomechanical analysis DMTA)with reference to morphological changes evaluated using scanning electron microscopy(SEM).The quality of the produced composites was assessed on the basis of the analysis of the surface topology of the injected composites.It has been shown that the larger particle size of used filler has a direct impact on increasing composite stiffness in the room and elevated temperature.Moreover,a relationship was demonstrated between the size of the filler and the deterioration of the tensile strength in the case of composites with a higher content of filler.The results show that the addition of sunflower husk as a particle-shaped waste filler is an effective method to increase sustainability of polypropylene-based green composites with beneficial thermomechanical properties and to reduce the residue of sunflower husk from industrial oil production.展开更多
The increasing use of the Internet with vehicles has made travel more convenient.However,hackers can attack intelligent vehicles through various technical loopholes,resulting in a range of security issues.Due to these...The increasing use of the Internet with vehicles has made travel more convenient.However,hackers can attack intelligent vehicles through various technical loopholes,resulting in a range of security issues.Due to these security issues,the safety protection technology of the in-vehicle system has become a focus of research.Using the advanced autoencoder network and recurrent neural network in deep learning,we investigated the intrusion detection system based on the in-vehicle system.We combined two algorithms to realize the efficient learning of the vehicle’s boundary behavior and the detection of intrusive behavior.In order to verify the accuracy and efficiency of the proposed model,it was evaluated using real vehicle data.The experimental results show that the combination of the two technologies can effectively and accurately identify abnormal boundary behavior.The parameters of the model are self-iteratively updated using the time-based back propagation algorithm.We verified that the model proposed in this study can reach a nearly 96%accurate detection rate.展开更多
Experimental and numerical investigation of heat transfer and fluid flow were conducted for classic heat exchanger elements (flat plate with fin-tubes in-line, staggered and with vortex generators) and corrugated-undu...Experimental and numerical investigation of heat transfer and fluid flow were conducted for classic heat exchanger elements (flat plate with fin-tubes in-line, staggered and with vortex generators) and corrugated-undulated ducts under transitional and weakly turbulent conditions.The dependence of average heat transfer and pressure drop on Reynolds number and geometrical parameters was investigated. Distributions of local heat transfer coefficient were obtained by using liquid crystal thermography and surface-averaged values were computed. Three-dimensional numerical simulations were conducted by a finite-volume method using a low-Reynolds number k-e model under the assumption of fully developed flow. Computed flow fields provided otherwise inaccessible information on the flow patterns and the mechanisms of heat transfer enhancement.展开更多
The effects of two different external carbon sources （acetate and ethanol） and electron acceptors （dissolved oxygen, nitrate, and nitrite） were investigated under aerobic and anoxic conditions with non-acclimated ...The effects of two different external carbon sources （acetate and ethanol） and electron acceptors （dissolved oxygen, nitrate, and nitrite） were investigated under aerobic and anoxic conditions with non-acclimated process bi- omass from a full-scale biological nutrient removal-activated sludge system. When acetate was added as an external carbon source, phosphate release was observed even in the presence of electron acceptors. The release rates were 1.7, 7.8, and 3.5 mg P/（g MLVSS.h） （MLVSS： mixed liquor volatile suspended solids）, respectively, for dissolved oxygen, nitrate, and nitrite. In the case of ethanol, no phosphate release was observed in the presence of electron acceptors. Results of the experiments with nitrite showed that approximately 25 mg NO2-N/L of nitrite inhibited anoxic phosphorus uptake regardless of the concentration of the tested external carbon sources. Furthermore, higher deni- trification rates were obtained with acetate （1.4 and 0.8 mg N/（g MLVSS.h）） compared to ethanol （1.1 and 0.7 mg N/ （g MLVSS.h）） for both anoxic electron acceptors （nitrate and nitrite）.展开更多
This paper presents an approach to design proportional-integral-derivative controllers for inductionmachines usingmeasurements.Most controlmethods developed for induc-tion machines are generally based on mathematical ...This paper presents an approach to design proportional-integral-derivative controllers for inductionmachines usingmeasurements.Most controlmethods developed for induc-tion machines are generally based on mathematical models.Due to complex dynamics of induction machines,identified models are often unable to perfectly describe their behaviour.Thus,the system performance will be limited by the quality of the identified model.Hence,developing control methods that do not require the availability of system model is advantageous.Here,we propose an approach that uses the frequency response data to directly design controllers.The main idea here is to find controller parameters so that the closed-loop frequency response fits a desired frequency response.Its main advantage is that errors associated with the modelling process are avoided.Moreover,the control design process does not depend on the order and complexity of the plant.A practical application to induction machines illustrates the efficacy of the proposed approach.展开更多
基金supported by the Open Fund of Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling (No.2020B121201003)the National Natural Science Foundation of China (Nos.21876099,22106088,and 22276110)+1 种基金the Key Research&Developmental Program of Shandong Province (No.2021CXGC011202)the Fundamental Research Funds of Shandong University (No.zy202102)。
文摘Advanced oxidation processes have been widely studied for organic pollutants treatment in water,but the degradation performance of radical-dominated pathway was severely inhibited by the side reactions between the anions and radicals,especially in high salinity conditions.Here,a singlet oxygen(^(1)O_(2))-dominated non-radical process was developed for organic pollutants degradation in high salinity wastewater,with layered crednerite(CuMnO_(2))as catalysts and peroxymonosulfate(PMS)as oxidant.Based on the experiments and density functional theory calculations,^(1)O_(2)was the dominating reactive species and the constructed Cu-O-Mn with electron-deficient Mn captured electron from PMS promoting the generation of^(1)O_(2).The rapid degradation of bisphenol A(BPA)was achieved by CuMnO_(2)/PMS system,which was 5-fold and 21-fold higher than that in Mn_(2)O_(3)/PMS system and Cu_(2)O/PMS system.The CuMnO_(2)/PMS system shown prominent BPA removal performance under high salinity conditions,prominent PMS utilization efficiency,outstanding total organic carbon removal rate,wide range of applicable pH and good stability.This work unveiled that the^(1)O_(2)-dominated non-radical process of CuMnO_(2)/PMS system overcame the inhibitory effect of anions in high salinity conditions,which provided a promising technique to remove organic pollutants from high saline wastewater.
文摘The accurate analysis of the seismic response of isolated structures requires incorporation of the flexibility of supporting soil. However, it is often customary to idealize the soil as rigid during the analysis of such structures. In this paper, seismic response time history analyses of base-isolated buildings modelled as linear single degree-of-freedom （SDOF） and multi degree-of-freedom （MDOF） systems with linear and nonlinear base models considering and ignoring the flexibility of supporting soil are conducted. The flexibility of supporting soil is modelled through a lumped parameter model consisting of swaying and rocking spring-dashpots. In the analysis, a large number of parametric studies for different earthquake excitations with three different peak ground acceleration （PGA） levels, different natural periods of the building models, and different shear wave velocities in the soil are considered. For the isolation system, laminated rubber bearings （LRBs） as well as high damping rubber bearings （HDRBs） are used. Responses of the isolated buildings with and without SSI are compared under different ground motions leading to the following conclusions： （1） soil flexibility may considerably influence the stiff superstructure response and may only slightly influence the response of the flexible structures; （2） the use of HDRBs for the isolation system induces higher structural peak responses with SSI compared to the system with LRBs; （3） although the peak response is affected by the incorporation of soil flexibility, it appears insensitive to the variation of shear wave velocity in the soil; （4） the response amplifications of the SDOF system become closer to unit with the increase in the natural period of the building, indicating an inverse relationship between SSI effects and natural periods for all the considered ground motions, base isolations and shear wave velocities; （5） the incorporation of SSI increases the number of significant cycles of large amplitude accelerati
文摘With an extensive range of distinctive features at nano meter-scale thicknesses,two-dimensional(2D)materials drawn the attention of the scientific community.Despite tremendous advancements in exploratory research on 2D materials,knowledge of 2D electrical transport and carrier dynamics still in its infancy.Thus,here we highlighted the electrical characteristics of 2D materials with electronic band structure,electronic transport,dielectric constant,carriers mobility.The atomic thinness of 2D materials makes substantially scaled field-effect transistors(FETs)with reduced short-channel effects conceivable,even though strong carrier mobility required for high performance,low-voltage device operations.We also discussed here about factors affecting 2D materials which easily enhanced the activity of those materials for various applications.Presently,Those 2D materials used in state-of-the-art electrical and optoelectronic devices because of the extensive nature of their electronic band structure.2D materials offer unprecedented freedom for the design of novel p-n junction device topologies in contrast to conventional bulk semiconductors.We also,describe the numerous 2D p-n junctions,such as homo junction and hetero junction including mixed dimensional junctions.Finally,we talked about the problems and potential for the future.
基金the COST Association and COST Action CA15107 "MultiFunctional Nano-Carbon Composite Materials Network (MultiComp)" for the financial supportRoyal Society via the Newton Fund for an Advanced Newton Fellowship at Queen Mary University of London which triggered this collaboration
文摘Here,we report the synthesis of hard carbon materials(RH) made from natural rice husk through a single pyrolysis process and their application as an anode in sodium-ion batteries.The studies show that the electrochemical properties of RHs are affected by the treatment temperatures,which determine the materials morphology,in particular,their degree of graphitization and extent of continuous channels(nanovoids).The latter are accessible to sodium ions and significantly contribute to charge storage capacity of the produced anodes.The RHs obtained at 1600 °C deliver the highest reversible capacity of276 mAh g^(-1) mainly due to insertion of sodium ions into the nanovoids.This work deepens the basic understanding of the influence of the carbonization temperature on the sodium storage mechanism.
基金supported by the“Human Resources Program in Energy Technology”of the Korea Institute of Energy Technology Evaluation and Planning(KETEP),granted financial resources from the Ministry of Trade,Industry&Energy,Republic of Korea(No.20204010600090).
文摘Despite the planned installation and operations of the traditional IEEE 802.11 networks,they still experience degraded performance due to the number of inefficiencies.One of the main reasons is the received signal strength indicator(RSSI)association problem,in which the user remains connected to the access point(AP)unless the RSSI becomes too weak.In this paper,we propose a multi-criterion association(WiMA)scheme based on software defined networking(SDN)in Wi-Fi networks.An association solution based on multi-criterion such as AP load,RSSI,and channel occupancy is proposed to satisfy the quality of service(QoS).SDNhaving an overall view of the network takes the association and reassociation decisions making the handoffs smooth in throughput performance.To implementWiMA extensive simulations runs are carried out on Mininet-NS3-Wi-Fi network simulator.The performance evaluation shows that the WiMA significantly reduces the average number of retransmissions by 5%–30%and enhances the throughput by 20%–50%,hence maintaining user fairness and accommodating more wireless devices and traffic load in the network,when compared to traditional client-driven(CD)approach and state of the art Wi-Balance approach.
基金supported by the National Science Foundation of China (Nos. 51978487 and 51678424)National Key Research and Development Program of China (No. 2019YFC1906402)the National Science Centre (No. 2017/26/D/ST8/00967)
文摘In this study,the effects of soluble readily biodegradable COD(sCOD)and particulate slowly biodegradable COD(pCOD)on anammox process were investigated.The results of the longterm experiment indicated that a low sCOD/N ratio of 0.5 could accelerate the anammox and denitrification activity,to reach as high as 84.9%±2.8%TN removal efficiency.Partial denitrification-anammox(PDN/anammox)and denitrification were proposed as the major pathways for nitrogen removal,accounting for 91.3% and 8.7% of the TN removal,respectively.Anammox bacteria could remain active with high abundance of anammox genes to maintain its dominance.Candidatus Kuenenia and Thauera were the predominant genera in the presence of organic matter.Compared with sCOD,batch experiments showed that the introduction of pCOD had a negative effect on nitrogen removal.The contribution of denitrification to nitrogen removal decreased from approximately 14%to 3% with increasing percentage of pCOD.In addition,the analysis result of the process data using an optimized ASM1 model indicated that high percentage of pCOD resulted in serious N_(2)O emission(the peak value up to 0.25mg N/L),whichwas likely due to limited mass diffusion and insufficient available carbon sources for denitrification.However,a high sCOD/N ratio was beneficial for alleviating N_(2)O accumulation.
基金funding from Researchers Supporting Project number(RSP2023R399),King Saud University,Riyadh,Saudi Arabia。
文摘Understanding the relationship between the properties and performance of black titanium dioxide with core-shell structure(CSBT)for environmental remediation is crucial for improving its prospects in practical applications.In this study,CSBT was synthesized using a glycerol-assisted sol-gel approach.The effect of different water-to-glycerol ratios(W:G=1:0,9:1,2:1,and 1:1)on the semiconducting and physicochemical properties of CSBT was investigated.The effectiveness of CSBT in removing phenolic compounds(PHCs)from real agro-industrial wastewater was studied.The CSBT synthesized with a W:G ratio of 9:1 has optimized properties for enhanced removal of PHCs.It has a distinct coreshell structure and an appropriate amount of Ti3+cations(11.18%),which play a crucial role in enhancing the performance of CSBT.When exposed to visible light,the CSBT performed better:48.30%of PHCs were removed after 180 min,compared to only 21.95%for TiO_(2) without core-shell structure.The CSBT consumed only 45.5235 kWh/m^(3) of electrical energy per order of magnitude and cost$2.4127 per unit volume of treated agro-industrial wastewater.Under the conditions tested,the CSBT demonstrated exceptional stability and reusability.The CSBT showed promising results in the treatment of phenols-containing agro-industrial wastewater.
文摘There are an increasing number of Narrow Band IoT devices being manufactured as the technology behind them develops quickly.The high co‐channel interference and signal attenuation seen in edge Narrow Band IoT devices make it challenging to guarantee the service quality of these devices.To maximise the data rate fairness of Narrow Band IoT devices,a multi‐dimensional indoor localisation model is devised,consisting of transmission power,data scheduling,and time slot scheduling,based on a network model that employs non‐orthogonal multiple access via a relay.Based on this network model,the optimisation goal of Narrow Band IoT device data rate ratio fairness is first established by the authors,while taking into account the Narrow Band IoT network:The multidimensional indoor localisation optimisation model of equipment tends to minimize data rate,energy constraints and EH relay energy and data buffer constraints,data scheduling and time slot scheduling.As a result,each Narrow Band IoT device's data rate needs are met while the network's overall performance is optimised.We investigate the model's potential for convex optimisation and offer an algorithm for optimising the distribution of multiple resources using the KKT criterion.The current work primarily considers the NOMA Narrow Band IoT network under a single EH relay.However,the growth of Narrow Band IoT devices also leads to a rise in co‐channel interference,which impacts NOMA's performance enhancement.Through simulation,the proposed approach is successfully shown.These improvements have boosted the network's energy efficiency by 44.1%,data rate proportional fairness by 11.9%,and spectrum efficiency by 55.4%.
文摘This paper analyses the issue of accelerated start-up of a marine steam turbine,which is an important problem because the start-up of a steam machine involves the combustion of fuel that is not transformed into useful energy.To find novel technologies that offer improvements in this aspect is essential due to restrictions on reducing ship emissions.Thus,the shorter the start-up time,the better for the environment and economy.High-pressure(HP)part of the turbine originally located on the Queen Elizabeth II unit was analysed.Advanced numerical calculations by thermal fluid-solid-interaction(Thermal FSI)were carried out.A series of simulations were performed for the accelerated start-up with controlled steam injection.A description of the chosen calculation methodology and the results obtained by simulation are included in this paper.The stress occurring during the accelerated start-up are approximately 40 MPa higher than those during the reference start-up.The relative elongations between the rotor and the hull during accelerated start-up reach a maximum value of 0.89 mm(0.83 mm for ultra-fast start-up).Reducing the steam turbine start-up time by 75%results in a 36.7 tons reduction in fuel consumption for start-up,resulting in an annual savings of 5372 USD.In conclusion,the concept proposed by the authors is safe,less expensive and does not affect the life of the turbine.In addition,results and applications from Siemens prove that additional injection of cooling steam is possible.
文摘Solid oxide fuel cells based on doped cefia electrolytes offer operating temperatures of -600℃. During recent years much atten- tion was aimed at successful powder preparation with high sinter activity and high conductivity. The properties of ceria electrolyte are very sensitive to impurities introduced during powder and electrolyte fabrication. One of the most successful and commercially available processes for the production of clean powders is based on the addition of several percent metallic cations that will react with impurities and segregate into the triple points of grain boundaries. In this work the results obtained from doping of CGO20 by 2% Ca and prepared by different routes were presented. The way of introducing Ca seemed to play an important role.
文摘Starting from the classical centrifugal compressor, cone shaped in meridional cross section, two modifications are considered on the basis of results from 2D and 3D flow models. The first modification is the change of the meridional cross section to hyperbolically shaped channel. The second modification, proposed on the basis of 2D axisymmetric solution, concerns the shape of blading. On the strength of this solution the blades are formed as 3D shaped blades, coinciding with the recent tendency in 3D designs. Two aims were considered for the change of meridional compressor shape. The first was to remove the separation zone which appears as the flow turns from axial to radial direction. The second aim is to uniformize the flow at exit of impeller. These two goals were considered within the frame of 2D axisymmetric model. Replacing the cone shaped compressor by a hyperbolically shaped one, the separation at the corner was removed. The disc and shroud shape of the compressor was chosen in the way which satisfies the condition of most uniform flow at the compressor exit. The uniformity of exit flow from the rotor can be considered as the factor which influences the performance of the diffuser following the rotor. In the 2D model a family of stream surfaces of S1 type is given in order to find S2 surfaces which may be identified with the midblade surfaces of compressor blading. A computation of 3D type has been performed in order to establish the relations between 2D and 3D models in the calculation of flow parameters. In the presented example the 2D model appears as the inverse model which leads to 3D shape of blading whereas the 3D model has been used for the direct solution. In the presented example the confrontation of two models, 2D and 3D, leads to a better understanding of the application of these models to the design procedure.
基金the Electromagnetic Design of Flexible Sensors Project under Grant No.POIR.04.04.00-00-1DC3/16-00,which is carried out within the Team-Tech Program of the Foundation for Polish Science co-financed by the European Union under the European Regional Development Fund,Smart Growth Operational Program 2014-2020.
文摘Electromagnetic simulation and electronic design automation(EDA)play an important role in the design of 5G antennas and radio chips.The simulation challenges include electromagnetic effects and long simulation time and this paper focuses on simulation software based on finite-element method(FEM).The state-of-the-art EDA software using novel computational techniques based on FEM can not only accelerate numerical analysis,but also enable optimization,sensitivity analysis and interactive design tuning based on rigorous electromagnetic model of a device.Several new techniques that help to mitigate the most challenging issues related to FEM based simulation are highlighted.In particular,methods for fast frequency sweep,mesh morphing and surrogate models for efficient optimization and manual design tuning are briefly described,and their efficiency is illustrated on examples involving a 5G multiple-input multiple-output(MIMO)antenna and filter.It is demonstrated that these new computational techniques enable significant reduction of time needed for design closure with the acceleration rates as large as tens or even over one hundred.
基金financially supported by the Polish National Science Centre:Grant No.2012/07/D/ST5/02269supported by the Foundation for Polish Science (FNP)+1 种基金the financial support from Polish National Science Centre under Grant No.2015/17/D/ ST5/02571the financial support from Polish National Science Centre under Grant No.2016/23/N/ST5/02071
文摘Ordered titanium dioxide nanotubes （TiOaNTs） modified with indium tin oxide （ITO） films were obtained via magnetron sputtering, in which ITO plate was used as a target, onto the as-anodized titania support followed by the calcination process. The morphology of fabricated material with deposited oxide was investigated using scanning electron microscopy. Raman and UV-Vis spectroscopies were utilized to characterize crystalline phase and optical properties of prepared samples, whereas X-ray photoelectron spectroscopy allowed determining the binding energy of present elements. In the case of titanium, three various oxidation states were identified and also the presence of indium and tin was confirmed. The electrochemical test carried out when the sample was exposed to light allows for selection of the most photoactive material. The highest photocurrent was registered when only 5-nm ITO layer was sputtered, and it equals 256 and 133 μA cm^-2 for the electrode material immersed in 0.5 M KOH and K2SO4 electrolytes, respectively, that is accordingly 3.5 and 4.4 times higher than the one observed for pristine titania. Furthermore, ITO-modified titania exhibits excellent photostability upon prolonged illumination that is of key importance for possible application in light-driven processes.
文摘Low-head hydraulic turbines are the subjects to individual approach of design. This comes from the fact that hydrological conditions are not of a standard character. Therefore, the design method of the hydraulic turbine stage has a great importance for those who may be interested in such an investment. As a first task in a design procedure the guide vane is considered. The proposed method is based on the solution of the inverse problem within the flame of 2D model. By the inverse problem authors mean a design of the blade shapes for given flow conditions. In the paper analytical solution for the simple cylindrical shape of a guide vane is presented. For the more realistic cases numerical solutions according to the axis-symmetrical model of the flow are also presented. The influence of such parameters as the inclination of trailing edge, the blockage factor due to blade thickness, the influence of loss due to dissipation are shown for the chosen simple geometrical example.
基金The results presented in this paper were partially funded with grants for education allocated by the Ministry of Science and Higher Education in Poland executed under the subject of No.02/25/SBAD/4630.
文摘Agricultural waste is a still untapped source of materials that can,in case of proper utilization,significantly improve the sustainability of polymers and their composites.In this work,polymer composites based on isotactic polypropylene were produced incorporating ground sunflower husk in the amount of 10 wt%and 20 wt%.The work’s main objective is to evaluate how preliminary fractioning of this agricultural waste filler affects the thermomechanical properties,microstructure and surface topology of polypropylene-based injection molded composites.The composites were analyzed for mechanical properties(tensile,impact strength and hardness),thermomechanical properties(Vicat softening point VST,heat deflection temperature HDT,and dynamic thermomechanical analysis DMTA)with reference to morphological changes evaluated using scanning electron microscopy(SEM).The quality of the produced composites was assessed on the basis of the analysis of the surface topology of the injected composites.It has been shown that the larger particle size of used filler has a direct impact on increasing composite stiffness in the room and elevated temperature.Moreover,a relationship was demonstrated between the size of the filler and the deterioration of the tensile strength in the case of composites with a higher content of filler.The results show that the addition of sunflower husk as a particle-shaped waste filler is an effective method to increase sustainability of polypropylene-based green composites with beneficial thermomechanical properties and to reduce the residue of sunflower husk from industrial oil production.
基金This work was supported by Research on the Influences of Network Security Threat Intelligence on Sichuan Government and Enterprises and the Development Countermeasure(Project ID 2018ZR0220)Research on Key Technologies of Network Security Protection in Intelligent Vehicle Based on(Project ID 2018JY0510)+3 种基金the Research on Abnormal Behavior Detection Technology of Automotive CAN Bus Based on Information Entropy(Project ID 2018Z105)the Research on the Training Mechanism of Driverless Network Safety Talents for Sichuan Auto Industry Based on Industry-University Synergy(Project ID 18RKX0667),Research and implementation of traffic cooperative perception and traffic signal optimization of main road(Project ID 2018YF0500707SN)Research and implementation of intelligent traffic control and monitoring system(Project ID 2019YGG0201)Remote upgrade system of intelligent vehicle software(Project ID 2018GZDZX0011).
文摘The increasing use of the Internet with vehicles has made travel more convenient.However,hackers can attack intelligent vehicles through various technical loopholes,resulting in a range of security issues.Due to these security issues,the safety protection technology of the in-vehicle system has become a focus of research.Using the advanced autoencoder network and recurrent neural network in deep learning,we investigated the intrusion detection system based on the in-vehicle system.We combined two algorithms to realize the efficient learning of the vehicle’s boundary behavior and the detection of intrusive behavior.In order to verify the accuracy and efficiency of the proposed model,it was evaluated using real vehicle data.The experimental results show that the combination of the two technologies can effectively and accurately identify abnormal boundary behavior.The parameters of the model are self-iteratively updated using the time-based back propagation algorithm.We verified that the model proposed in this study can reach a nearly 96%accurate detection rate.
文摘Experimental and numerical investigation of heat transfer and fluid flow were conducted for classic heat exchanger elements (flat plate with fin-tubes in-line, staggered and with vortex generators) and corrugated-undulated ducts under transitional and weakly turbulent conditions.The dependence of average heat transfer and pressure drop on Reynolds number and geometrical parameters was investigated. Distributions of local heat transfer coefficient were obtained by using liquid crystal thermography and surface-averaged values were computed. Three-dimensional numerical simulations were conducted by a finite-volume method using a low-Reynolds number k-e model under the assumption of fully developed flow. Computed flow fields provided otherwise inaccessible information on the flow patterns and the mechanisms of heat transfer enhancement.
基金Project supported by the European Regional Development Fund within the Framework of the Innovative Economy Operational Program 2007-2013(No.UDA-POIG.01.03.01-22-140/09-04)the CARbon BALAncing for Nutrient Control in Wastewater Treatment(CARBALA)(No.PIRSES-GA-2011-295176)the National Water Pollution Control and Management of Science and Technology in China(No.2015ZX07218001)
文摘The effects of two different external carbon sources （acetate and ethanol） and electron acceptors （dissolved oxygen, nitrate, and nitrite） were investigated under aerobic and anoxic conditions with non-acclimated process bi- omass from a full-scale biological nutrient removal-activated sludge system. When acetate was added as an external carbon source, phosphate release was observed even in the presence of electron acceptors. The release rates were 1.7, 7.8, and 3.5 mg P/（g MLVSS.h） （MLVSS： mixed liquor volatile suspended solids）, respectively, for dissolved oxygen, nitrate, and nitrite. In the case of ethanol, no phosphate release was observed in the presence of electron acceptors. Results of the experiments with nitrite showed that approximately 25 mg NO2-N/L of nitrite inhibited anoxic phosphorus uptake regardless of the concentration of the tested external carbon sources. Furthermore, higher deni- trification rates were obtained with acetate （1.4 and 0.8 mg N/（g MLVSS.h）） compared to ethanol （1.1 and 0.7 mg N/ （g MLVSS.h）） for both anoxic electron acceptors （nitrate and nitrite）.
基金NPRP grant NPRP09-1153-2-450 from the Qatar National Research Fund(a member of Qatar Foundation).
文摘This paper presents an approach to design proportional-integral-derivative controllers for inductionmachines usingmeasurements.Most controlmethods developed for induc-tion machines are generally based on mathematical models.Due to complex dynamics of induction machines,identified models are often unable to perfectly describe their behaviour.Thus,the system performance will be limited by the quality of the identified model.Hence,developing control methods that do not require the availability of system model is advantageous.Here,we propose an approach that uses the frequency response data to directly design controllers.The main idea here is to find controller parameters so that the closed-loop frequency response fits a desired frequency response.Its main advantage is that errors associated with the modelling process are avoided.Moreover,the control design process does not depend on the order and complexity of the plant.A practical application to induction machines illustrates the efficacy of the proposed approach.
