A new experimental method is developed to investigate the effect of dissolved substances on the evaporation rate of small water droplets suspended in the atmosphere.The laboratory setup is based on converting a genera...A new experimental method is developed to investigate the effect of dissolved substances on the evaporation rate of small water droplets suspended in the atmosphere.The laboratory setup is based on converting a generated droplet jet of complex structure into a directed flow of evaporating droplets falling in a vertical tube.Images of falling droplets captured by a high-speed camera through a window in the vertical channel wall are used to determine the sizes and velocities of individual droplets.The computational modeling of droplet motion and evaporation proved useful at all stages of the experimental work:from selecting the position of the vertical channel to processing the experimental data.It was found that even a 0.1%mass concentration of the dissolved ionic salt KCl has a considerable effect on decreasing the evaporation rate of the droplets.In contrast,a typical fungicide with a mass concentration of 2.5%has only a slight impact on the evaporation rate.The laboratory results enabled the authors to refine the evaporation model of water droplets to account for the presence of dissolved substances.Modified models of this type are expected to be useful in controling crop spraying and also in other potential applications.展开更多
In recent years,rockburst have gained significant attention as a crucial topic in rock engineering.Strain andfault-slip rockburst are two common types that occur frequently and cause substantial damage.The objective o...In recent years,rockburst have gained significant attention as a crucial topic in rock engineering.Strain andfault-slip rockburst are two common types that occur frequently and cause substantial damage.The objective of thisreview is to conduct a comprehensive study on the experiments and failure mechanisms of strain and fault-slip rockburst.Firstly,the article analyzes the evolving trends in experimental research on rockburst in the past decade,highlightingmechanical properties and failure modes as the primary research focuses in understanding rockburst mechanisms.Subsequently,it provides an overview of the experimental techniques and methods employed for studying both types ofrockburst.Then,with a focus on the mechanical properties and failure modes,the article conducts an extensive analysisof the failure mechanisms associated with strain and fault-slip rockburst.By analyzing experimental data and observingthe failure characteristics of samples,it discusses the variations and common features exhibited by these two types ofrockburst under various test conditions.This analysis is of paramount importance in revealing the causes of rockburstformation and development,as well as in predicting rockburst trends and assessing associated risks.Lastly,thelimitations of current rockburst experiments and future research directions are discussed,followed by a comprehensivesummary of the entire article.展开更多
The optimal experimental methods of a multidimensional dynamic programming,a large-scale linear and a complex nonlinear system are presented,which achieve a great step forward in the field of systems science.And excel...The optimal experimental methods of a multidimensional dynamic programming,a large-scale linear and a complex nonlinear system are presented,which achieve a great step forward in the field of systems science.And excellent results are obtained in the applications of complex water resource systems.展开更多
Mixed-variable problems are inevitable in engineering. However, few researches pay attention to discrete variables. This paper proposed a mixed-variable experimental design method (ODCD): first, the design variables w...Mixed-variable problems are inevitable in engineering. However, few researches pay attention to discrete variables. This paper proposed a mixed-variable experimental design method (ODCD): first, the design variables were divided into discrete variables and continuous variables;then, the DVD method was employed for handling discrete variables, the LHD method was applied for continuous variables, and finally, a Columnwise-Pairwise Algorithm was used for the overall optimization of the design matrix. Experimental results demonstrated that the ODCD method outperforms in terms of the sample space coverage performance.展开更多
demand for faster vessels continues to grow,various high speed vessels have been designed and constructed for military,recreational,and passenger use.Planing vessels,specifically engineered for high-speed travel,requi...demand for faster vessels continues to grow,various high speed vessels have been designed and constructed for military,recreational,and passenger use.Planing vessels,specifically engineered for high-speed travel,require optimization to improve their hydrodynamic performance and stability during design.Reducing resistance and improving longitudinal stability are key challenges in the design of high-speed vessels.Various methods are employed to overcome these challenges,with the use of a transverse step being one of the most common approaches.This study explores the effect of changing the angle of the aft-wise step and incorporates these changes into existing analytical formulas,resulting in new formulas specifically for high-speed vessels equipped with aft-wise steps.This research investigates how the angle of the transverse step affects the hydrodynamic performance and longitudinal stability of high-speed vessels.Based on the results,analytical formulas have been developed to calculate the wetted surface parameters of vessels equipped with an aft-wise transverse step.The study used experimental methods to analyze the vessel's behavior with six different aft-wise transverse step angles of 0°,9°,11°,13°,15°,and 17°at three speeds of 8,10,and 12 m/s.In the experimental tests,the hydrodynamic components of resistance,trim angle,and wetted surface of the vessel were measured.Results indicate that creating an angle in the transverse step substantially improves the hydrodynamic components and longitudinal stability of the vessel.At the optimal angle,the resistance and trim angle of the vessel were reduced by 7.8%and 12.8%,respectively,compared to the base vessel.Additionally,the existing analytical methods for calculating the wetted surface area are more accurate than similar methods.展开更多
Nitrogen oxides(NO_(x))and particulate matter(PM)present significant risks to both human health and environmental sustainability.The Integrated Dust Removal and Denitrification Technology(DRDt)offers a more efficient ...Nitrogen oxides(NO_(x))and particulate matter(PM)present significant risks to both human health and environmental sustainability.The Integrated Dust Removal and Denitrification Technology(DRDt)offers a more efficient and cost-effective solution for achieving ultralow industrial flue gas emissions;however,its effectiveness is undermined by low catalyst load rates and poor stability in filter materials.This study addresses these limitations by modifying conventional PTFE filter media(PTFE-Tim)through the incorporation of sodium alginate(SA)and dopamine(DA)as modifiers,resulting in two new filter materials:PTFE-SA-MOF and PTFE-DA-MOF.By optimizing the parameters of an orthogonal experimental design,we identified the ideal preparation conditions for these composite materials.The addition of SA and DA enhanced the bonding between the catalyst(Mn-Cu-MOF)crystal particles and the PTFE fibers through mechanisms such as ion exchange,hydrogen bonding,and adhesion.Consequently,the catalyst loading rate and stability of the DRDt filters were significantly improved.Specifically,the PTFE-SA-MOF and PTFE-DA-MOF filters achieved high catalyst loading rates of 15.97% and 15.86%,these values represent improvements of 2.53 and 2.51 times,while maintaining excellent stability,with mass retention rates of 98.64% and 98.27%,respectively,over the conventional PTFE-Tim filter.展开更多
This study examines the efficacy of Avicennia marina(AM)leaves as an environmentally sustainable biosorbent for the extraction of methylene blue(MB)dye from wastewater.A hybrid approach of Response Surface Methodology...This study examines the efficacy of Avicennia marina(AM)leaves as an environmentally sustainable biosorbent for the extraction of methylene blue(MB)dye from wastewater.A hybrid approach of Response Surface Methodology(RSM)and Artificial Neural Networks(ANN)was implemented to assess,optimize,and forecast biosorption effectiveness across different operating parameters.The experimental design employed a Central Composite Design(CCD)methodology,focusing on critical parameters including pH,initial dye concentration,temperature,and biosorbent dosage.The ideal biosorption parameters were identified as a temperature of 44.3℃,pH 7.1,a biosorbent dosage of 0.3 grams,and an initial dye concentration of 48.4 mg/L,resulting in a maximum removal efficiency of 84.26%.The ANN model exhibited significant prediction accuracy,so confirming its appropriateness for predicting and enhancing intricate biosorption processes.The findings underscore that AM leaves constitute a cost-efficient,plentiful,and ecologically sustainable resource for wastewater treatment purposes.Furthermore,the amalgamation of RSM and ANN shown significant efficacy in process optimization and forecasting.These findings provide significant insights into the advancement of eco-friendly solutions for the treatment of dye-contaminated water.Subsequent study must prioritize the amplification of the procedure for industrial applications,the execution of ongoing system assessments,and the evaluation of the enduring environmental and economic ramifications of utilizing AM leaves as a biosorbent.展开更多
Widespread usage of bump-type foil journal bearing(BFJB) in oil-free microturbomachinery requires accurate predictions of dynamic performance characteristics, although it remains a challenging issue because BFJB refle...Widespread usage of bump-type foil journal bearing(BFJB) in oil-free microturbomachinery requires accurate predictions of dynamic performance characteristics, although it remains a challenging issue because BFJB reflects nonlinear both structurally and aerodynamically.This paper presented a simple experimental method to semi-directly obtain the minimum film thickness and dynamic stiffness of BFJB using the journal orbit. Numerical calculations and simulations are conducted to validate the experimental method. The micro-deformation and interaction of various foils are taken into consideration to improve the model precision. The results from the numerical model regarding the BFJB dynamic characteristics are compared with the experimental results coming from a dedicated test rig, which shows that the experimental results fluctuate obviously and agree not well with the numerical results at the start stage due to the presence of dry friction at that time, nevertheless, they show fantastic agreement as soon as a gas film is gradually generated to separate the shaft from the top foil. Therefore, the proposed experimental method is effective to predict film thickness and dynamic characteristics during the period from the lift-off time to the land-off time. The dynamic characteristics, along with the journal orbits also can be used to rapidly predict the dynamics behavior of rotor-bearing systems.展开更多
Flexible roll forming is a promising manufacturing method for the production of variable cross section products. Considering the large plastic strain in this forming process which is much larger than that of uniform d...Flexible roll forming is a promising manufacturing method for the production of variable cross section products. Considering the large plastic strain in this forming process which is much larger than that of uniform deformation phase of uniaxial tensile test, the widely adopted method of simulating the forming processes with non-supplemented material data from uniaxial tensile test will certainly lead to large error. To reduce this error, the material data is supplemented based on three constitutive models. Then a finite element model of a six passes flexible roll forming process is established based on the supplemented material data and the original material data from the uniaxial tensile test. The flexible roll forming experiment of a B pillar reinforcing plate is carried out to verify the proposed method. Final cross section shapes of the experimental and the simulated results are compared. It is shown that the simulation calculated with supplemented material data based on Swift model agrees well with the experimental results, while the simulation based on original material data could not predict the actual deformation accurately. The results indicate that this material supplement method is reliable and indispensible, and the simulation model can well reflect the real metal forming process. Detailed analysis of the distribution and history of plastic strain at different positions are performed. A new material data supplement method is proposed to tackle the problem which is ignored in other roll forming simulations, and thus the forming process simulation accuracy can be greatly improved.展开更多
In this paper,the effect of water and air fluids on the behavior of a planing catamaran in calm water was studied separately in calm water by using experimental and numerical methods.Experiments were conducted in a to...In this paper,the effect of water and air fluids on the behavior of a planing catamaran in calm water was studied separately in calm water by using experimental and numerical methods.Experiments were conducted in a towing tank over the Froude number range of 0.49–2.9 with two degrees of freedom.The model vessel displacement of 5.3 kg was implemented in experimental tests.Craft behavior was evaluated at the displacements of 5.3,4.6,and 4 kg by using the numerical method.The numerical simulation results for the hull’s resistance force were validated with similar experimental data.The fluid volume model was applied to simulate two-phase flow.The SST k-ωturbulence model was used to investigate the effect of turbulence on the catamaran.The results showed that in the planing mode,the contribution of air to pressure resistance increased by 55%,40%,and 60%at the mentioned displacements,whereas the contribution of air to friction resistance was less than 15%on average.The contribution of the air to the total lift force at the abovementioned displacements exceeded 70%,60%,and 50%in the planing mode but was less than 10%in the displacement mode.At the displacements of 5.3 and 4 kg,the area under the effect of maximum pressure moved around the center of gravity and caused porpoising longitudinal instability at the Froude numbers of 2.9 and 2.4,respectively.However,at the displacement of 4.6 kg,this effect did not occur,and the vessel maintained its stability.展开更多
The laws of influence of different factors have been analyzed in order to enhance the working efficiency and fatigue life of the cleaning element in brush shape of the sugarcane harvester. Based on the principle of or...The laws of influence of different factors have been analyzed in order to enhance the working efficiency and fatigue life of the cleaning element in brush shape of the sugarcane harvester. Based on the principle of orthogonal experiment design, the virtual-orthogonal-experimental analysis for the cleaning element is carried out on the finite element analysis （FEA） software-ANSYS after analyzing the nonlinear structural behavior in the working procedure. The results are analyzed with the overall balancing method, and then the optimal combination is got, which is made up of different levels of different factors. Also the optimal combination of design parameters of the cleaning element received fiom the virtual experimental analysis is conducted an experiment to confirm that the virtual analysis model and results are right, and the effect of factors on the function of the cleaning element is obtained by more analysis and further optimizing.展开更多
Almost all the cellular processes in a living system are controlled by proteins:They regulate gene expression,catalyze chemical reactions,transport small molecules across membranes,and transmit signal across membranes...Almost all the cellular processes in a living system are controlled by proteins:They regulate gene expression,catalyze chemical reactions,transport small molecules across membranes,and transmit signal across membranes.Even,a viral infection is often initiated through virus-host protein interactions.Protein-protein interactions(PPIs)are the physical contacts between two or more proteins and they represent complex biological functions.Nowadays,PPIs have been used to construct PPI networks to study complex pathways for revealing the functions of unknown proteins.Scientists have used PPIs to find the molecular basis of certain diseases and also some potential drug targets.In this review,we will discuss how PPI networks are essential to understand the molecular basis of virus-host relationships and several databases which are dedicated to virus-host interaction studies.Here,we present a short but comprehensive review on PPIs,including the experimental and computational methods of finding PPIs,the databases dedicated to virus-host PPIs,and the associated various applications in protein interaction networks of some lethal viruses with their hosts.展开更多
Objective： The aim of this project was to train highly professional and specialized nursing students from medical colleges to adapt to bedside clinical care by exploring and discussing various methods of injection an...Objective： The aim of this project was to train highly professional and specialized nursing students from medical colleges to adapt to bedside clinical care by exploring and discussing various methods of injection and IV infusion in animal experimentation to hone the core professional nursing competencies. Methods： Two classes from the 2012 senior graduating nursing class were randomly selected by a computer to conduct the diversified practical teaching methods based on animal experimentation. A hospital environment was simulated by requiring students to perform different types of injections and practical IV infusion techniques. A comprehensive evaluation of the core professional competencies, as well as other integrated competencies, was conducted to determine the effectiveness of the teaching methods. Results： Two-sampled, pairwise u-tests were performed between the scores of the experimental （nursing class 2） and control （nursing class 1） groups. These findings showed that the overall test scores were significantly higher in the experimental group compared to the control group and that the average P-values for the competencies in various categories were 〈0.01, which indicated statistically significant results. Conclusions： Based on the data from this project, diversified teaching methods for basic nursing training founded on animal experimentation can help nursing students perfect their core professional competencies and improve their overall professional standing. The introduction of animal experimentation requires further verification, and an increased acknowledgement of its benefits through the widespread dissemination of this information.展开更多
To analyze the spring disturbance torque caused by motionai cable harness in a stabilized platform, the Kirchhoff theory based cable harness model has been previously developed to dynamically simulate the motional cab...To analyze the spring disturbance torque caused by motionai cable harness in a stabilized platform, the Kirchhoff theory based cable harness model has been previously developed to dynamically simulate the motional cable harness. In this paper, this model was validated by comparing the simulation results with the experiment results （ both the spring force and the deformed profile of the motional cable harness）. In the experiment, a special optical measuring instrument based on binocular vision was developed and the motion and deformation of cable harness were measured. A simpli- fied stabilized platform system was constructed, and the absolute value of spring disturbance force during the motion of this simplified frame was obtained by using a force gauge （0. 02 N precision）. The physical parameters of experimental specimen were also measured. The experimental and simulated results showed good agreement. These results should be useful for better motional cable harness layout design and reliable evaluation of the spring disturbance torque.展开更多
This work is an experimental approach based on the method of experimental plans to determine a specific formulation of a resin concrete. In this study, an unsaturated polyester resin （thermosetting resin） was used w...This work is an experimental approach based on the method of experimental plans to determine a specific formulation of a resin concrete. In this study, an unsaturated polyester resin （thermosetting resin） was used with two types of mineral fillers （dune sand and crushed sand）, and with the addition of a marble powder to ensure the continuity of the particle size mixing granular. The lack of the methods for developing this kind of composite materials, had led us to perform an initial experimental approach to define the experimental field, that is to say determine the mass proportions of the various compounds of mixture of our study. In the second approach, we have established and implemented fully experimental plans with three factors namely： factor （1）： sand, factor （2）： resin, factor （3）： marble powder. Test results being the density of polymer concrete and the mechanical resistances. Finally, multi-parameters regression allowed us to determine predictive mathematical models for the different responses of the study. Tests results showed that at three days we got a tensile strength of about 16 MPa with a resin concrete density of 1.9 g/cm3. This shows the advantages of this material.展开更多
In multi-phase flows, the phases can flow and arranged in different spatial configurations in the pipe, which called flow patterns. This type of flow is found in the oil, chemical and nuclear industries. For example, ...In multi-phase flows, the phases can flow and arranged in different spatial configurations in the pipe, which called flow patterns. This type of flow is found in the oil, chemical and nuclear industries. For example, in the production and transport of oil and gas, the identification of the flow patterns are essential for answering those questions which are related to the economic return of the field, such as, measuring the volumetric flow, determining the pressure drop along the flow lines, production management and supervision. In offshore production, these factors are very important. This paper presents a new method for measuring the void fraction in horizontal pipelines, taking the air as gas in water-air two-phase flow. Through acoustic analysis of the frequency response of the pipe, the method gets the parameters to changes in runoff regime, in an experimental arrangement constructed on a small scale. The main advantages are the non-intrusive characteristic and easy to implement. The paper is composed of a qualitative experimental evaluation and transducers （microphone） which are used to analyze variations in the response accompanying variations in void and flow pattern changes. Changes are imposed and controlled by a two-phase flow experimental simulation rig, including a measurement cell constituted of an external casing that can isolate the measurement from the environmental background noise fitted with acoustic pressure transducers radially arranged, and the impact of a monitored excitation mechanism. The signals which captured by the microphones are processed and analyzed by checking their frequency contents changes according to the amount of air in the mixture.展开更多
In this paper, on the basis of experimental data of two kinds of chemical explosions, the piston-pushing model of spherical blast-waves and the second-order Godunov-type scheme of finite difference methods with high i...In this paper, on the basis of experimental data of two kinds of chemical explosions, the piston-pushing model of spherical blast-waves and the second-order Godunov-type scheme of finite difference methods with high identification to discontinuity are used to the numerical reconstruction of part of an actual hemispherical blast-wave flow field by properly adjusting the moving bounary conditions of a piston. This method is simple and reliable. It is suitable to the evaluation of effects of the blast-wave flow field away from the explosion center.展开更多
DOE （design of experiments） is a systematic, rigorous approach to engineering problem-solving that applies principles and techniques at the data collection stage so as to ensure the generation of valid, defensible, ...DOE （design of experiments） is a systematic, rigorous approach to engineering problem-solving that applies principles and techniques at the data collection stage so as to ensure the generation of valid, defensible, and supportable engineering conclusions. This paper presents a comparison of three different experimental designs （full experimental design, fractional design and Taguchi design） aimed at studying the effects of cutting parameters variations on surface finish. The results revealed that the effects obtained by analyzing both fractional and Taguchi designs were comparable to the main effects and two-level interactions obtained by the full factorial design. Thus, we conclude that full factorial design appear to be reliable and more economical since they permit to reduce by a factor the amount of time and effort required to conduct the experimental design without losing valuable information. Thus, we conclude that full factorial design appear to be reliable and more economical and without losing valuable information.展开更多
This paper presents a detailed experimental and numerical study of aerodynamically produced noise which occurs due to turbulent structures created by the cowl cavity and side mirror. Measurements were carried out at V...This paper presents a detailed experimental and numerical study of aerodynamically produced noise which occurs due to turbulent structures created by the cowl cavity and side mirror. Measurements were carried out at Volvo aerodynamical wind tunnel on a Volvo XC60 production model. The configurations considered here are： side mirror On/Off with the cowl cavity open/closed. The results of exterior sound source mapping （with the intensity probe placed in the flow stream） have been compared with the results of the measurements inside the car. The contribution of the cowl area to overall wind noise level is measured in terms of AI% （Articulation Index） inside the compartment. It was shown that increase in AI by 2% could be attributed to the cowl generated wind noise. Transient numerical simulations of the turbulent flow around the car have been performed for all configurations. The results of the simulations show similarity to experimental results and give insight to the flow structures around the car.展开更多
To overcome the shortcomings of the traditional passive ranging technology based on image, such as poor ranging accuracy, low reliability and complex system, a new visual passive ranging method based on re-entrant coa...To overcome the shortcomings of the traditional passive ranging technology based on image, such as poor ranging accuracy, low reliability and complex system, a new visual passive ranging method based on re-entrant coaxial optical path is presented. The target image is obtained using double cameras with coaxial optical path. Since there is imaging optical path difference between the cameras, the images are different. In comparison of the image differences, the target range could be reversed. The principle of the ranging method and the ranging model are described. The relationship among parameters in the ranging process is analyzed quantitatively. Meanwhile,the system composition and technical realization scheme are also presented. Also, the principle of the method is verified by the equivalent experiment. The experimental results show that the design scheme is correct and feasible with good robustness. Generally, the ranging error is less than 10% with good convergence. The optical path is designed in a re-entrant mode to reduce the volume and weight of the system. Through the coaxial design,the visual passive range of the targets with any posture can be obtained in real time. The system can be widely used in electro-optical countermeasure and concealed photoelectric detection.展开更多
基金financially supported by the Russian Science Foundation(project No.24-29-00303:https://rscf.ru/project/24-29-00303/,accessed on 01 July 2025).
文摘A new experimental method is developed to investigate the effect of dissolved substances on the evaporation rate of small water droplets suspended in the atmosphere.The laboratory setup is based on converting a generated droplet jet of complex structure into a directed flow of evaporating droplets falling in a vertical tube.Images of falling droplets captured by a high-speed camera through a window in the vertical channel wall are used to determine the sizes and velocities of individual droplets.The computational modeling of droplet motion and evaporation proved useful at all stages of the experimental work:from selecting the position of the vertical channel to processing the experimental data.It was found that even a 0.1%mass concentration of the dissolved ionic salt KCl has a considerable effect on decreasing the evaporation rate of the droplets.In contrast,a typical fungicide with a mass concentration of 2.5%has only a slight impact on the evaporation rate.The laboratory results enabled the authors to refine the evaporation model of water droplets to account for the presence of dissolved substances.Modified models of this type are expected to be useful in controling crop spraying and also in other potential applications.
基金Project(52227901)supported by the National Natural Science Foundation of ChinaProject(2308085ME153)supported by the Anhui Provincial Natural Science Foundation,China+2 种基金Project(2022AH030088)supported by the University Natural Science Foundation of Anhui Province,ChinaProject(EC2022011)supported by the Foundation of Joint National-Local Engineering Research Centre for Safe and Precise Coal Mining,ChinaProject(GXXT-2022-020)supported by the University Synergy Innovation Program of Anhui Province,China。
文摘In recent years,rockburst have gained significant attention as a crucial topic in rock engineering.Strain andfault-slip rockburst are two common types that occur frequently and cause substantial damage.The objective of thisreview is to conduct a comprehensive study on the experiments and failure mechanisms of strain and fault-slip rockburst.Firstly,the article analyzes the evolving trends in experimental research on rockburst in the past decade,highlightingmechanical properties and failure modes as the primary research focuses in understanding rockburst mechanisms.Subsequently,it provides an overview of the experimental techniques and methods employed for studying both types ofrockburst.Then,with a focus on the mechanical properties and failure modes,the article conducts an extensive analysisof the failure mechanisms associated with strain and fault-slip rockburst.By analyzing experimental data and observingthe failure characteristics of samples,it discusses the variations and common features exhibited by these two types ofrockburst under various test conditions.This analysis is of paramount importance in revealing the causes of rockburstformation and development,as well as in predicting rockburst trends and assessing associated risks.Lastly,thelimitations of current rockburst experiments and future research directions are discussed,followed by a comprehensivesummary of the entire article.
基金supported hy the National Natural Science Foundation of China(Grant No 79400011)the 333 Engineering Foundation of Jhiangsu Province of China.
文摘The optimal experimental methods of a multidimensional dynamic programming,a large-scale linear and a complex nonlinear system are presented,which achieve a great step forward in the field of systems science.And excellent results are obtained in the applications of complex water resource systems.
文摘Mixed-variable problems are inevitable in engineering. However, few researches pay attention to discrete variables. This paper proposed a mixed-variable experimental design method (ODCD): first, the design variables were divided into discrete variables and continuous variables;then, the DVD method was employed for handling discrete variables, the LHD method was applied for continuous variables, and finally, a Columnwise-Pairwise Algorithm was used for the overall optimization of the design matrix. Experimental results demonstrated that the ODCD method outperforms in terms of the sample space coverage performance.
文摘demand for faster vessels continues to grow,various high speed vessels have been designed and constructed for military,recreational,and passenger use.Planing vessels,specifically engineered for high-speed travel,require optimization to improve their hydrodynamic performance and stability during design.Reducing resistance and improving longitudinal stability are key challenges in the design of high-speed vessels.Various methods are employed to overcome these challenges,with the use of a transverse step being one of the most common approaches.This study explores the effect of changing the angle of the aft-wise step and incorporates these changes into existing analytical formulas,resulting in new formulas specifically for high-speed vessels equipped with aft-wise steps.This research investigates how the angle of the transverse step affects the hydrodynamic performance and longitudinal stability of high-speed vessels.Based on the results,analytical formulas have been developed to calculate the wetted surface parameters of vessels equipped with an aft-wise transverse step.The study used experimental methods to analyze the vessel's behavior with six different aft-wise transverse step angles of 0°,9°,11°,13°,15°,and 17°at three speeds of 8,10,and 12 m/s.In the experimental tests,the hydrodynamic components of resistance,trim angle,and wetted surface of the vessel were measured.Results indicate that creating an angle in the transverse step substantially improves the hydrodynamic components and longitudinal stability of the vessel.At the optimal angle,the resistance and trim angle of the vessel were reduced by 7.8%and 12.8%,respectively,compared to the base vessel.Additionally,the existing analytical methods for calculating the wetted surface area are more accurate than similar methods.
基金financially supported by Natural Science Foundation of Anhui Provincial Department of Education(2022AH050337)State Key Laboratory of Safety and Health for Metal Mines(2022-JSKSSYS-04)the Project of National Key Research and Development Program(2022YFC3901405).
文摘Nitrogen oxides(NO_(x))and particulate matter(PM)present significant risks to both human health and environmental sustainability.The Integrated Dust Removal and Denitrification Technology(DRDt)offers a more efficient and cost-effective solution for achieving ultralow industrial flue gas emissions;however,its effectiveness is undermined by low catalyst load rates and poor stability in filter materials.This study addresses these limitations by modifying conventional PTFE filter media(PTFE-Tim)through the incorporation of sodium alginate(SA)and dopamine(DA)as modifiers,resulting in two new filter materials:PTFE-SA-MOF and PTFE-DA-MOF.By optimizing the parameters of an orthogonal experimental design,we identified the ideal preparation conditions for these composite materials.The addition of SA and DA enhanced the bonding between the catalyst(Mn-Cu-MOF)crystal particles and the PTFE fibers through mechanisms such as ion exchange,hydrogen bonding,and adhesion.Consequently,the catalyst loading rate and stability of the DRDt filters were significantly improved.Specifically,the PTFE-SA-MOF and PTFE-DA-MOF filters achieved high catalyst loading rates of 15.97% and 15.86%,these values represent improvements of 2.53 and 2.51 times,while maintaining excellent stability,with mass retention rates of 98.64% and 98.27%,respectively,over the conventional PTFE-Tim filter.
文摘This study examines the efficacy of Avicennia marina(AM)leaves as an environmentally sustainable biosorbent for the extraction of methylene blue(MB)dye from wastewater.A hybrid approach of Response Surface Methodology(RSM)and Artificial Neural Networks(ANN)was implemented to assess,optimize,and forecast biosorption effectiveness across different operating parameters.The experimental design employed a Central Composite Design(CCD)methodology,focusing on critical parameters including pH,initial dye concentration,temperature,and biosorbent dosage.The ideal biosorption parameters were identified as a temperature of 44.3℃,pH 7.1,a biosorbent dosage of 0.3 grams,and an initial dye concentration of 48.4 mg/L,resulting in a maximum removal efficiency of 84.26%.The ANN model exhibited significant prediction accuracy,so confirming its appropriateness for predicting and enhancing intricate biosorption processes.The findings underscore that AM leaves constitute a cost-efficient,plentiful,and ecologically sustainable resource for wastewater treatment purposes.Furthermore,the amalgamation of RSM and ANN shown significant efficacy in process optimization and forecasting.These findings provide significant insights into the advancement of eco-friendly solutions for the treatment of dye-contaminated water.Subsequent study must prioritize the amplification of the procedure for industrial applications,the execution of ongoing system assessments,and the evaluation of the enduring environmental and economic ramifications of utilizing AM leaves as a biosorbent.
基金funded by the Natural Science Foundation of China (No. 51775025, 51205015)China Key Research and Development Plan (No. 2017YFB0102102, 2018YFB0104100)。
文摘Widespread usage of bump-type foil journal bearing(BFJB) in oil-free microturbomachinery requires accurate predictions of dynamic performance characteristics, although it remains a challenging issue because BFJB reflects nonlinear both structurally and aerodynamically.This paper presented a simple experimental method to semi-directly obtain the minimum film thickness and dynamic stiffness of BFJB using the journal orbit. Numerical calculations and simulations are conducted to validate the experimental method. The micro-deformation and interaction of various foils are taken into consideration to improve the model precision. The results from the numerical model regarding the BFJB dynamic characteristics are compared with the experimental results coming from a dedicated test rig, which shows that the experimental results fluctuate obviously and agree not well with the numerical results at the start stage due to the presence of dry friction at that time, nevertheless, they show fantastic agreement as soon as a gas film is gradually generated to separate the shaft from the top foil. Therefore, the proposed experimental method is effective to predict film thickness and dynamic characteristics during the period from the lift-off time to the land-off time. The dynamic characteristics, along with the journal orbits also can be used to rapidly predict the dynamics behavior of rotor-bearing systems.
基金Supported by National Natural Science Foundation of China(Grant Nos.51205004,51475003)Beijing Municipal Natural Science Foundation of China(Grant No.3152010)Beijing Municipal Education Committee Science and Technology Program,China(Grant No.KM201510009004)
文摘Flexible roll forming is a promising manufacturing method for the production of variable cross section products. Considering the large plastic strain in this forming process which is much larger than that of uniform deformation phase of uniaxial tensile test, the widely adopted method of simulating the forming processes with non-supplemented material data from uniaxial tensile test will certainly lead to large error. To reduce this error, the material data is supplemented based on three constitutive models. Then a finite element model of a six passes flexible roll forming process is established based on the supplemented material data and the original material data from the uniaxial tensile test. The flexible roll forming experiment of a B pillar reinforcing plate is carried out to verify the proposed method. Final cross section shapes of the experimental and the simulated results are compared. It is shown that the simulation calculated with supplemented material data based on Swift model agrees well with the experimental results, while the simulation based on original material data could not predict the actual deformation accurately. The results indicate that this material supplement method is reliable and indispensible, and the simulation model can well reflect the real metal forming process. Detailed analysis of the distribution and history of plastic strain at different positions are performed. A new material data supplement method is proposed to tackle the problem which is ignored in other roll forming simulations, and thus the forming process simulation accuracy can be greatly improved.
文摘In this paper,the effect of water and air fluids on the behavior of a planing catamaran in calm water was studied separately in calm water by using experimental and numerical methods.Experiments were conducted in a towing tank over the Froude number range of 0.49–2.9 with two degrees of freedom.The model vessel displacement of 5.3 kg was implemented in experimental tests.Craft behavior was evaluated at the displacements of 5.3,4.6,and 4 kg by using the numerical method.The numerical simulation results for the hull’s resistance force were validated with similar experimental data.The fluid volume model was applied to simulate two-phase flow.The SST k-ωturbulence model was used to investigate the effect of turbulence on the catamaran.The results showed that in the planing mode,the contribution of air to pressure resistance increased by 55%,40%,and 60%at the mentioned displacements,whereas the contribution of air to friction resistance was less than 15%on average.The contribution of the air to the total lift force at the abovementioned displacements exceeded 70%,60%,and 50%in the planing mode but was less than 10%in the displacement mode.At the displacements of 5.3 and 4 kg,the area under the effect of maximum pressure moved around the center of gravity and caused porpoising longitudinal instability at the Froude numbers of 2.9 and 2.4,respectively.However,at the displacement of 4.6 kg,this effect did not occur,and the vessel maintained its stability.
基金This project is supported by National Natural Science Foundation of China(No.50365001).
文摘The laws of influence of different factors have been analyzed in order to enhance the working efficiency and fatigue life of the cleaning element in brush shape of the sugarcane harvester. Based on the principle of orthogonal experiment design, the virtual-orthogonal-experimental analysis for the cleaning element is carried out on the finite element analysis （FEA） software-ANSYS after analyzing the nonlinear structural behavior in the working procedure. The results are analyzed with the overall balancing method, and then the optimal combination is got, which is made up of different levels of different factors. Also the optimal combination of design parameters of the cleaning element received fiom the virtual experimental analysis is conducted an experiment to confirm that the virtual analysis model and results are right, and the effect of factors on the function of the cleaning element is obtained by more analysis and further optimizing.
基金National Natural Science Foundation of China,No.31971180 and No.11474013.
文摘Almost all the cellular processes in a living system are controlled by proteins:They regulate gene expression,catalyze chemical reactions,transport small molecules across membranes,and transmit signal across membranes.Even,a viral infection is often initiated through virus-host protein interactions.Protein-protein interactions(PPIs)are the physical contacts between two or more proteins and they represent complex biological functions.Nowadays,PPIs have been used to construct PPI networks to study complex pathways for revealing the functions of unknown proteins.Scientists have used PPIs to find the molecular basis of certain diseases and also some potential drug targets.In this review,we will discuss how PPI networks are essential to understand the molecular basis of virus-host relationships and several databases which are dedicated to virus-host interaction studies.Here,we present a short but comprehensive review on PPIs,including the experimental and computational methods of finding PPIs,the databases dedicated to virus-host PPIs,and the associated various applications in protein interaction networks of some lethal viruses with their hosts.
基金supported by 2012 Jiangxi Province Higher Education Reform Research Provincial Research Project(No.JXJG-12-29-3)
文摘Objective： The aim of this project was to train highly professional and specialized nursing students from medical colleges to adapt to bedside clinical care by exploring and discussing various methods of injection and IV infusion in animal experimentation to hone the core professional nursing competencies. Methods： Two classes from the 2012 senior graduating nursing class were randomly selected by a computer to conduct the diversified practical teaching methods based on animal experimentation. A hospital environment was simulated by requiring students to perform different types of injections and practical IV infusion techniques. A comprehensive evaluation of the core professional competencies, as well as other integrated competencies, was conducted to determine the effectiveness of the teaching methods. Results： Two-sampled, pairwise u-tests were performed between the scores of the experimental （nursing class 2） and control （nursing class 1） groups. These findings showed that the overall test scores were significantly higher in the experimental group compared to the control group and that the average P-values for the competencies in various categories were 〈0.01, which indicated statistically significant results. Conclusions： Based on the data from this project, diversified teaching methods for basic nursing training founded on animal experimentation can help nursing students perfect their core professional competencies and improve their overall professional standing. The introduction of animal experimentation requires further verification, and an increased acknowledgement of its benefits through the widespread dissemination of this information.
基金Supported by the National Natural Science Foundation of China(50805009)
文摘To analyze the spring disturbance torque caused by motionai cable harness in a stabilized platform, the Kirchhoff theory based cable harness model has been previously developed to dynamically simulate the motional cable harness. In this paper, this model was validated by comparing the simulation results with the experiment results （ both the spring force and the deformed profile of the motional cable harness）. In the experiment, a special optical measuring instrument based on binocular vision was developed and the motion and deformation of cable harness were measured. A simpli- fied stabilized platform system was constructed, and the absolute value of spring disturbance force during the motion of this simplified frame was obtained by using a force gauge （0. 02 N precision）. The physical parameters of experimental specimen were also measured. The experimental and simulated results showed good agreement. These results should be useful for better motional cable harness layout design and reliable evaluation of the spring disturbance torque.
文摘This work is an experimental approach based on the method of experimental plans to determine a specific formulation of a resin concrete. In this study, an unsaturated polyester resin （thermosetting resin） was used with two types of mineral fillers （dune sand and crushed sand）, and with the addition of a marble powder to ensure the continuity of the particle size mixing granular. The lack of the methods for developing this kind of composite materials, had led us to perform an initial experimental approach to define the experimental field, that is to say determine the mass proportions of the various compounds of mixture of our study. In the second approach, we have established and implemented fully experimental plans with three factors namely： factor （1）： sand, factor （2）： resin, factor （3）： marble powder. Test results being the density of polymer concrete and the mechanical resistances. Finally, multi-parameters regression allowed us to determine predictive mathematical models for the different responses of the study. Tests results showed that at three days we got a tensile strength of about 16 MPa with a resin concrete density of 1.9 g/cm3. This shows the advantages of this material.
文摘In multi-phase flows, the phases can flow and arranged in different spatial configurations in the pipe, which called flow patterns. This type of flow is found in the oil, chemical and nuclear industries. For example, in the production and transport of oil and gas, the identification of the flow patterns are essential for answering those questions which are related to the economic return of the field, such as, measuring the volumetric flow, determining the pressure drop along the flow lines, production management and supervision. In offshore production, these factors are very important. This paper presents a new method for measuring the void fraction in horizontal pipelines, taking the air as gas in water-air two-phase flow. Through acoustic analysis of the frequency response of the pipe, the method gets the parameters to changes in runoff regime, in an experimental arrangement constructed on a small scale. The main advantages are the non-intrusive characteristic and easy to implement. The paper is composed of a qualitative experimental evaluation and transducers （microphone） which are used to analyze variations in the response accompanying variations in void and flow pattern changes. Changes are imposed and controlled by a two-phase flow experimental simulation rig, including a measurement cell constituted of an external casing that can isolate the measurement from the environmental background noise fitted with acoustic pressure transducers radially arranged, and the impact of a monitored excitation mechanism. The signals which captured by the microphones are processed and analyzed by checking their frequency contents changes according to the amount of air in the mixture.
文摘In this paper, on the basis of experimental data of two kinds of chemical explosions, the piston-pushing model of spherical blast-waves and the second-order Godunov-type scheme of finite difference methods with high identification to discontinuity are used to the numerical reconstruction of part of an actual hemispherical blast-wave flow field by properly adjusting the moving bounary conditions of a piston. This method is simple and reliable. It is suitable to the evaluation of effects of the blast-wave flow field away from the explosion center.
文摘DOE （design of experiments） is a systematic, rigorous approach to engineering problem-solving that applies principles and techniques at the data collection stage so as to ensure the generation of valid, defensible, and supportable engineering conclusions. This paper presents a comparison of three different experimental designs （full experimental design, fractional design and Taguchi design） aimed at studying the effects of cutting parameters variations on surface finish. The results revealed that the effects obtained by analyzing both fractional and Taguchi designs were comparable to the main effects and two-level interactions obtained by the full factorial design. Thus, we conclude that full factorial design appear to be reliable and more economical since they permit to reduce by a factor the amount of time and effort required to conduct the experimental design without losing valuable information. Thus, we conclude that full factorial design appear to be reliable and more economical and without losing valuable information.
文摘This paper presents a detailed experimental and numerical study of aerodynamically produced noise which occurs due to turbulent structures created by the cowl cavity and side mirror. Measurements were carried out at Volvo aerodynamical wind tunnel on a Volvo XC60 production model. The configurations considered here are： side mirror On/Off with the cowl cavity open/closed. The results of exterior sound source mapping （with the intensity probe placed in the flow stream） have been compared with the results of the measurements inside the car. The contribution of the cowl area to overall wind noise level is measured in terms of AI% （Articulation Index） inside the compartment. It was shown that increase in AI by 2% could be attributed to the cowl generated wind noise. Transient numerical simulations of the turbulent flow around the car have been performed for all configurations. The results of the simulations show similarity to experimental results and give insight to the flow structures around the car.
基金Supported by the National Basic Research Program of China under Grant No 2014CB340102
文摘To overcome the shortcomings of the traditional passive ranging technology based on image, such as poor ranging accuracy, low reliability and complex system, a new visual passive ranging method based on re-entrant coaxial optical path is presented. The target image is obtained using double cameras with coaxial optical path. Since there is imaging optical path difference between the cameras, the images are different. In comparison of the image differences, the target range could be reversed. The principle of the ranging method and the ranging model are described. The relationship among parameters in the ranging process is analyzed quantitatively. Meanwhile,the system composition and technical realization scheme are also presented. Also, the principle of the method is verified by the equivalent experiment. The experimental results show that the design scheme is correct and feasible with good robustness. Generally, the ranging error is less than 10% with good convergence. The optical path is designed in a re-entrant mode to reduce the volume and weight of the system. Through the coaxial design,the visual passive range of the targets with any posture can be obtained in real time. The system can be widely used in electro-optical countermeasure and concealed photoelectric detection.
