An internal ballistic model of electromagnetic railgun based on PFN coupled with multi-physical field and experimental validation

To accelerate the practicality of electromagnetic railguns,it is necessary to use a combination of threedimensional numerical simulation and experiments to study the mechanism of bore damage.In this paper,a three-dimensional numerical model of the augmented railgun with four parallel unconventional rails is introduced to simulate the internal ballistic process and realize the multi-physics field coupling calculation of the rail gun,and a test experiment of a medium-caliber electromagnetic launcher powered by pulse formation network(PFN)is carried out.Various test methods such as spectrometer,fiber grating and high-speed camera are used to test several parameters such as muzzle initial velocity,transient magnetic field strength and stress-strain of rail.Combining the simulation results and experimental data,the damage condition of the contact surface is analyzed.

Adaptive Robust Servo Control for Vertical Electric Stabilization System of Tank and Experimental Validation

A tracking stability control problem for the vertical electric stabilization system of moving tank based on adaptive robust servo control is addressed.This paper mainly focuses on two types of possibly fast timevarying but bounded uncertainty within the vertical electric stabilization system:model parameter uncertainty and uncertain nonlinearity.First,the vertical electric stabilization system is constructed as an uncertain nonlinear dynamic system that can reflect the practical mechanics transfer process of the system.Second,the dynamical equation in the form of state space is established by designing the angular tracking error.Third,the comprehensive parameter of system uncertainty is designed to estimate the most conservative effects of uncertainty.Finally,an adaptive robust servo control which can effectively handle the combined effects of complex nonlinearity and uncertainty is proposed.The feasibility of the proposed control strategy under the practical physical condition is validated through the tests on the experimental platform.This paper pioneers the introduction of the internal nonlinearity and uncertainty of the vertical electric stabilization system into the settlement of the tracking stability control problem,and validates the advanced servo control strategy through experiment for the first time.

Prediction of ground-borne vibration induced by impact pile driving:numerical approach and experimental validation

Deep foundations are currently used in engineering practice to solve problems caused by weak geotechnical characteristics of the ground.Impact pile driving is an interesting and viable solution from economic and technical points of view.However,it is necessary to ensure that the environmental drawbacks,namely ground-borne vibration,are adequately met.For this purpose,the authors propose an axisymmetric finite element method-perfectly matched layer(FEM-PML)approach,where the nonlinear behavior of the soil is addressed through an equivalent linear methodology.Given the complexity of the problem,an experimental test site was developed and fully characterized.The experimental work comprised in-situ and laboratory soil characterization,as well as the measurement of vibrations induced during pile driving.The comparison between experimental and numerical results demonstrated a very good agreement,from which it can be concluded that the proposed numerical approach is suitable for the prediction of vibrations induced by impact pile driving.The experimental database is available as supplemental data and may be used by other researchers in the validation of their prediction models.

A Train-Bridge Dynamic Interaction Analysis Method and Its Experimental Validation

The train-bridge dynamic interaction problem began with the development of railway technology, and requires an evaluation method for bridge design in order to ensure the safety and stability of the bridge and the running train. This problem is studied using theoretical analysis, numerical simulation, and experimental study. In the train-bridge dynamic interaction system proposed in this paper, the train vehicle model is established by the rigid-body dynamics method, the bridge model is established by the finite element method, and the wheel/rail vertical and lateral interaction are simulated by the corresponding assumption and the Kalker linear creep theory, respectively. Track irregularity, structure deformation, wind load, collision load, structural damage, foundation scouring, and earthquake action are regarded as the excitation for the system. The train-bridge dynamic interaction system is solved by inter-history iteration. A case study of the dynamic response of a CRH380BL high-speed train running through a standard-design bridge in China is discussed. The dynamic responses of the vehicle and of the bridge subsystems are obtained for speeds ranging from 200 km-b-1 to 400 km.h-1, and the vibration mechanism are analyzed.

Experimental validation method of elastic thin rod model for simulating the motional cable harness

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.

Therapeutic Mechanism of Kai Xin San on Alzheimer's Disease Based on Network Pharmacology and Experimental Validation

Objective: To explore the specific pharmacological molecular mechanisms of Kai Xin San(KXS)on treating Alzheimer’s disease(AD) based on network pharmacology and experimental validation. Methods:The chemical compounds of KXS and their corresponding targets were screened using the Encyclopedia of Traditional Chinese Medicine(ETCM) database. AD-related target proteins were obtained from MalaCards database and DisGeNET databases. Key compounds and targets were identified from the compound-targetdisease network and protein-protein interaction(PPI) network analysis. Functional enrichment analysis predicted the potential key signaling pathways involved in the treatment of AD with KXS. The binding affinities between key ingredients and targets were further verified using molecular docking. Finally, the predicted key signaling pathway was validated experimentally. Positioning navigation and space search experiments were conducted to evaluate the cognitive improvement effect of KXS on AD rats. Western blot was used to further examine and investigate the expression of the key target proteins related to the predicted pathway. Results: In total, 38active compounds and 469 corresponding targets of KXS were screened, and 264 target proteins associated with AD were identified. The compound-target-disease and PPI networks identified key active ingredients and protein targets. Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway analysis suggested a potential effect of KXS in the treatment of AD via the amyloid beta(Aβ)-glycogen synthase kinase-3 beta(GSK3β)-Tau pathway. Molecular docking revealed a high binding affinity between the key ingredients and targets. In vivo,KXS treatment significantly improved cognitive deficits in AD rats induced by Aβ1-42, decreased the levels of Aβ, p-GSK3β, p-Tau and cyclin-dependent kinase 5, and increased the expressions of protein phosphatase 1alpha(PP1A) and PP2A(P<0.05 or P<0.01). Conclusion: KXS exerted neuroprotective effects by regulating the Aβ-GSK3β-Tau signaling pathway, which provides novel insights into the therapeutic mechanism of KXS and a feasible pharmacological strategy for the treatment of AD.

Network pharmacology and experimental validation of Maxing Shigan decoction in the treatment of influenza virus-inducedferroptosis

Influenza is an acute viral respiratory infection that has caused high morbidity and mortality worldwide.Influenza A virus(IAV)has been found to activate multiple programmed cell death pathways,including ferroptosis.Ferroptosis is a novel form of programmed cell death in which the accumulation of intracellular iron promotes lipid peroxidation,leading to cell death.However,little is known about how influenza viruses induce ferroptosis in the host cells.In this study,based on network pharmacology,we predicted the mechanism of action of Maxing Shigan decoction(MXSGD)in IAV-induced ferroptosis,and found that this process was related to biological processes,cellular components,molecular function and multiple signaling pathways,where the hypoxia inducible factor-1(HIF-1)signaling pathway plays a significant role.Subsequently,we constructed the mouse lung epithelial(MLE-12)cell model by IAV-infected in vitro cell experiments,and revealed that IAV infection induced cellular ferroptosis that was characterized by mitochondrial damage,increased reactive oxygen species(ROS)release,increased total iron and iron ion contents,decreased expression of ferroptosis marker gene recombinant glutathione peroxidase 4(GPX4),increased expression of acyl-CoA synthetase long chain family member 4(ACSL4),and enhanced activation of hypoxia inducible factor-1α(HIF-1α),induced nitric oxide synthase(iNOS)and vascular endothelial growth factor(VEGF)in the HIF-1 signaling pathway.Treatment with MXSGD effectively reduced intracellular viral load,while reducing ROS,total iron and ferrous ion contents,repairing mitochondrial results and inhibiting the expression of cellular ferroptosis and the HIF-1 signaling pathway.Finally,based on animal experiments,it was found that MXSGD effectively alleviated pulmonary congestion,edema and inflammation in IAV-infected mice,and inhibited the expression of ferroptosis-related protein and the HIF-1 signaling pathway in lung tissues.

Potential-dependent insights into the origin of high ammonia yield rate on copper surface via nitrate reduction:A computational and experimental study

Focusing on revealing the origin of high ammonia yield rate on Cu via nitrate reduction(NO3RR),we herein applied constant potential method via grand-canonical density functional theory(GC-DFT)with implicit continuum solvation model to predict the reaction energetics of NO3RR on pure copper surface in alkaline media.The potential-dependent mechanism on the most prevailing Cu(111)and the minor(100)and(110)facets were established,in consideration of NO_(2)_(−),NO,NH_(3),NH_(2)OH,N_(2),and N_(2)O as the main products.The computational results show that the major Cu(111)is the ideal surface to produce ammonia with the highest onset potential at 0.06 V(until−0.37 V)and the highest optimal potential at−0.31 V for ammonia production without kinetic obstacles in activation energies at critical steps.For other minor facets,the secondary Cu(100)shows activity to ammonia from−0.03 to−0.54 V with the ideal potential at−0.50 V,which requires larger overpotential to overcome kinetic activation energy barriers.The least Cu(110)possesses the longest potential range for ammonia yield from−0.27 to−1.12 V due to the higher adsorption coverage of nitrate,but also with higher tendency to generate di-nitrogen species.Experimental evaluations on commercial Cu/C electrocatalyst validated the accuracy of our proposed mechanism.The most influential(111)surface with highest percentage in electrocatalyst determined the trend of ammonia production.In specific,the onset potential of ammonia production at 0.1 V and emergence of yield rate peak at−0.3 V in experiments precisely located in the predicted potentials on Cu(111).Four critical factors for the high ammonia yield and selectivity on Cu surface via NO3RR are summarized,including high NO3RR activity towards ammonia on the dominant Cu(111)facet,more possibilities to produce ammonia along different pathways on each facet,excellent ability for HER inhibition and suitable surface size to suppress di-nitrogen species formation at high nitrate coverage.Overall,our work provides comprehensive potential-dependent insights into the reaction details of NO3RR to ammonia,which can serve as references for the future development of NO3RR electrocatalysts,achieving higher activity and selectivity by maximizing these characteristics of copper-based materials.

Potential application of Nardostachyos Radix et Rhizoma-Rhubarb for the treatment of diabetic kidney disease based on network pharmacology and cell culture experimental verification

BACKGROUND Diabetic kidney disease(DKD)is one of the serious complications of diabetes mellitus,and the existing treatments cannot meet the needs of today's patients.Traditional Chinese medicine has been validated for its efficacy in DKD after many years of clinical application.However,the specific mechanism by which it works is still unclear.Elucidating the molecular mechanism of the Nardostachyos Radix et Rhizoma-rhubarb drug pair(NRDP)for the treatment of DKD will provide a new way of thinking for the research and development of new drugs.AIM To investigate the mechanism of the NRDP in DKD by network pharmacology combined with molecular docking,and then verify the initial findings by in vitro experiments.METHODS The Traditional Chinese Medicine Systems Pharmacology(TCMSP)database was used to screen active ingredient targets of NRDP.Targets for DKD were obtained based on the Genecards,OMIM,and TTD databases.The VENNY 2.1 database was used to obtain DKD and NRDP intersection targets and their Venn diagram,and Cytoscape 3.9.0 was used to build a"drug-component-target-disease"network.The String database was used to construct protein interaction networks.Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analysis and Gene Ontology analysis were performed based on the DAVID database.After selecting the targets and the active ingredients,Autodock software was used to perform molecular docking.In experimental validation using renal tubular epithelial cells(TCMK-1),we used the Cell Counting Kit-8 assay to detect the effect of NRDP on cell viability,with glucose solution used to mimic a hyperglycemic environment.Flow cytometry was used to detect the cell cycle progression and apoptosis.Western blot was used to detect the protein expression of STAT3,p-STAT3,BAX,BCL-2,Caspase9,and Caspase3.RESULTS A total of 10 active ingredients and 85 targets with 111 disease-related signaling pathways were obtained for NRDP.Enrichment analysis of KEGG pathways was performed to determine advanced glycation end products(AGEs)-receptor for AGEs(RAGE)signaling as the core pathway.Molecular docking showed good binding between each active ingredient and its core targets.In vitro experiments showed that NRDP inhibited the viability of TCMK-1 cells,blocked cell cycle progression in the G0/G1 phase,and reduced apoptosis in a concentrationdependent manner.Based on the results of Western blot analysis,NRDP differentially downregulated p-STAT3,BAX,Caspase3,and Caspase9 protein levels(P<0.01 or P<0.05).In addition,BAX/BCL-2 and p-STAT3/STAT3 ratios were reduced,while BCL-2 and STAT3 protein expression was upregulated(P<0.01).CONCLUSION NRDP may upregulate BCL-2 and STAT3 protein expression,and downregulate BAX,Caspase3,and Caspase9 protein expression,thus activating the AGE-RAGE signaling pathway,inhibiting the vitality of TCMK-1 cells,reducing their apoptosis.and arresting them in the G0/G1 phase to protect them from damage by high glucose.

A study of miRNAs targets prediction and experimental validation

microRNAs(miRNAs)are 20–24 nucleotide(nt)RNAs that regulate eukaryotic gene expression post-transcriptionally by the degradation or translational inhibition of their target messenger RNAs(mRNAs).To identify miRNA target genes will help a lot by understanding their biological functions.Sophisticated computational approaches for miRNA target prediction,and effective biological techniques for validating these targets now play a central role in elucidating their functions.Owing to the imperfect complementarity of animal miRNAs with their targets,it is difficult to judge the accuracy of the prediction.Complexity of regulation by miRNA-mediated targets at protein and mRNAs levels has made it more challenging to identify the targets.To date,only a few miRNAs targets are confirmed.In this article,we review the methods of miRNA target prediction and the experimental validation for their corresponding mRNA targets in animals.

Dynamic simulation and experimental validation of a two-phase closed thermosyphon for geothermal application

The heat transfer perfonmance of a vertical two-phase closed thermosyphon(TPCT)used in a geothermal heat pump was experimentally investigated.The TPCT is a verticalplain steel pipe with inner diameter of 114 mm and bored 368 m deep underground.Carbon dioxide(CO_(2))is used as working fluid.In the TPCT there is no condensation section.CO_(2)is condensed by the evaporator pf the heat pump,flows into the head of the TPCT and nuns down as a falling film along the inner wall of the pipe.For the heat transfer simulation in the TPCT,a quasi-dynamic model in which the mass transfer between the liquid and vapor phases as well as the conduction heat transfer from the surrounding soil towards the pipe is treated dynamically.However the film flow modeling is based on the Nusselt theory of frilm condenssation.The compauison of the experimental data with the numerical simulation is presented and discussed.

Research Progress in Digging and Validation of miRNA Target Genes Using Experimental Methods

MicroRNAs （miRNAs） are a group of regulatory RNAs that regulate gene expression post-transcriptionally by the degradation or translational inhibition of their target messenger RNAs （mRNAs）. Regulation is accomplished when the 22-25 nucleotide miRNAs bind to complementary sequences in the 3＇-untranslated regions （UTR）. One barrier to miRNA research is to find target genes. Although computational target predictions have shed light on important aspects of microRNA target recognition, questions remain concerning the rates of false positives. In addition, we do not completely understand how microRNAs can recognize and regulate their targets. As such, experimental positive predictions and allow for an unbiased stu ap dy proaches are required, which can reflect in vivo processes, eliminating false of microRNA target recognition. In this review, we summarized experimental approaches that have been described for the identification and validation of mRNA targets associated with specific miRNAs.

FE SIMULATION AND EXPERIMENTAL VALIDATION OF POWDER MIXED EDM PROCESS FOR ESTIMATING THE TEMPERATURE DISTRIBUTION AND VOLUME REMOVED IN SINGLE CRATER

This study reports the results of a finite element simulation of powder mixed electric discharge machining process for H11 Hot Die steel material using relevant boundary conditions and reasonable assumptions.The crater shape was developed using simulated temperature profiles to estimate the volume removed in a single crater.The temperature distribution on the workpiece was used to predict the cooling rate and calculate the stresses generated due to thermal loading.Subsequently,the simulation results were experimentally validated by physically measuring the crater shape and volume.From the results it was concluded that about 25%of heat is transmitted to the workpiece during machining at the process conditions used in the experiment.The microscopic pictures showed bigger craters with increase in current.The machined surface showed overlapping craters with surface cracks suggesting a high cooling rate.

Experimental Study of a Modified Icaro Solar Dryer: The Case of Coffee Drying

Food losses in the developing country are thought to be 50% of the fruits and vegetables grown and 25% of harvested food grain. Food preservation can reduce wastage of a harvest surplus, allow storage for food shortages, and in some cases facilitate export to high-value markets. Drying is one of the oldest methods of food preservation. Drying makes produce lighter, smaller, and less likely to spoil and helps to minimize the moisture content in coffee beans as high moisture content during storage is certain to ruin the taste and appearance of coffee. This work presents the results of an experimental study of forced convection drying of coffee cherries in a modified Icaro solar dryer. The study aims to validate the numerical models developed for further research. The experimental tests envisaged also aim to determine the mass loss curves of the product by fixing or calculating its initial mass (1 kg), its initial water content (70%), the ambient temperature, the drying airflow (0.02 m3.s-1 to 0.09 m3.s-1) and the exchange coefficients. The influence of these aerothermal parameters on the drying time of a most commercialized coffee variety (Robusta) was studied. Finally, the results revealed an increase in the efficiency of the heat transfer air and a reduction in the water content of the coffee cherry from 70% to 9.87%, after 30.2 hours.

The BOUT Project; Validation and Benchmark of BOUT Code and Experimental Diagnostic Tools for Fusion Boundary Turbulence

A boundary plasma turbulence code BOUT is presented. The preliminary encour- aging results have been obtained when comparing with probe measurements for a typical Ohmic discharge in HT-7 tokamak. The validation and benchmark of BOUT code and experimental diagnostic tools for fusion boundary plasma turbulence is proposed.

Analysis of the cracks formation on surface of extruded magnesium rod based on numerical modeling and experimental verification

To reduce the surface cracks of extrusion rod for AZ31 magnesium caused by nonhomogeneous metal flow in extrusion process, 3D computer finite element （FE） simulations of extruding a wrought magnesium alloy AZ31 into rods have been performed and the results have been verified in extrusion experiments under identical conditions. The tendency to generate the dead zone is decreased by employing the die angle 60° at the cone-shaped die comparing with the die angle 180°. The surface additional tensile stresses of the rod at the die exit are decreased greatly so that the surface cracks caused are avoided by using the die angle 60°. The extrusion die with die angle 180° would increase the higher temperature rise and possibility of crack formation on the rod surface that caused by die angle 60° and temperature rise decrease tensile strength of the AZ31 rod. The experimental results show that die angle 180° could cause continuous cracks on the surface of the extruded rod. The extrusion force required is reduced approximately 15 ton by employing the die angle 60°. Theoretical results obtained by the DeformTM-3D simulation agreed well with the experiments. The obtained results provide the fundamental and also practical guidelines for the design and correction of dies to produce magnesium rod with good surface quality.

Hover performance estimation and validation of battery powered vertical takeoff and landing aircraft

Battery powered vertical takeoff and landing(VTOL) aircraft attracts more and more interests from public, while limited hover endurance hinders many prospective applications. Based on the weight models of battery, motor and electronic speed controller, the power consumption model of propeller and the constant power discharge model of battery, an efficient method to estimate the hover endurance of battery powered VTOL aircraft was presented. In order to understand the mechanism of performance improvement, the impacts of propulsion system parameters on hover endurance were analyzed by simulations, including the motor power density, the battery capacity, specific energy and Peukert coefficient. Ground experiment platform was established and validation experiments were carried out, the results of which showed a well agreement with the simulations. The estimation method and the analysis results could be used for optimization design and hover performance evaluation of battery powered VTOL aircraft.

Prediction of the mechanisms of liver injury of Epimedii Folium by network pharmacology and validation in HepaRG Cells

Objective:EpimediiFolium(EF),a traditional Chinese medicinal material,has the effect of tonifying kidney Yang,strengthening bones and treating rheumatism.However,its clinical applications are limited by its drug-induced liver injury(DILI)effects and the underlying mechanisms have not been elucidated.Methods:Active EF compounds were obtained from the TCMSP database and their targets predicted in Targetnet.Next,DILI-targets were obtained from CTD,Genecards and Digsee databases.Protein-protein interactions of EF DILI-targets were determined using STRING and hub targets identified via topological analyses.Then,hub targets were subjected to GO and KEGG pathway enrichment analyses.Finally,HepaRG cells were used for further validation of molecular mechanisms.Results:Fifty seven active compounds and 164 targets that interacted with these active compounds were identified with Sagittatoside A,icariside I,and Icariin being the best active compounds.Enrichment analysis revealed the PI3K/Akt and NF-kB signaling pathways to be markedly enriched.Molecular docking revealed that Sagittatoside A,icariside I and Icariin had good binding activities to RAC1,PTGS2,and NOS3.Validation analysis in HepaRG cells revealed that Epimedium flavonoids upregulated RAC1,PTGS2 and NOS3 levels.Conclusion:Our findings show that EF induces oxidative stress,inflammation,and apoptosis via PI3K/Akt and NF-kB signaling pathways,and provides a basis for more in-depth studies on EF-induced DILI.

Mathematical Model and Experiment Validation of Fluid Torque by Shear Stress under Influence of Fluid Temperature in Hydro-viscous Clutch

The current design of hydro-viscous clutch（HVC） in tracked vehicle fan transmission mainly focuses on high-speed and high power. However, the fluid torque under the influence of fluid temperature can not be predicted accurately by conventional mathematical model or experimental research. In order to validate the fluid torque of HVC by taking the viscosity-temperature characteristic of fluid into account, the test rig is designed. The outlet oil temperature is measured and fitted with different rotation speed, oil film thickness, oil flow rate, and inlet oil temperature. Meanwhile, the film torque can be obtained. Based on Navier-Stokes equations and the continuity equation, the mathematical model of fluid torque is proposed in cylindrical coordinate. Iterative method is employed to solve the equations. The radial and tangential speed distribution, radial pressure distribution and theoretical flow rate are determined and analyzed. The models of equivalent radius and fluid torque of friction pairs are introduced. The experimental and theoretical results indicate that tangential speed distribution is mainly determined by the relative rotating speed between the friction plate and the separator disc. However, the radial speed distribution and pressure distribution are dominated by pressure difference at the lower rotating speed. The oil film fills the clearance and the film torque increases with increasing rotating speed. However, when the speed reaches a certain value, the centrifugal force will play an important role on the fluid distribution. The pressure is negative at the outer radius when inlet flow rate is less than theoretical flow, so the film starts to shrink which decreases the film torque sharply. The theoretical fluid torque has good agreement with the experimental data. This research proposes a new fluid torque mathematical model which may predict the film torque under the influence of temperature more accurately.

Understanding the alkyl effect of geminal dinitropropyl ester energetic plasticizers on hydroxyl terminated polybutadiene(HTPB):Simultaneous tuning on low temperature behavior and processability

Geminal dinitropropyl ester plasticizers(DNPEPs) possess excellent energetic performances which provide good potentials as insensitive plasticizer. In this study, we design and synthesize DNPEPs with different alkane chain parts, and systematically investigate their structure-property relationships.Results show that DNPEPs have impact sensitivities all higher than 25.2 J, thermal decomposition temperatures all higher than 254 ℃, and glass transition temperatures(T_(g)) lower than-90 ℃.Furthermore, the effects of DNPEPs as plasticizer are studied on hydroxyl terminated polybutadiene(HTPB) in detail, including the viscosity, glass transition temperatures and others. It is noteworthy that 2,2-dinitropropyl nonanoate(DNPNc) among these DNPEPs exhibits the most expected simultaneous tuning effects on both viscosity and T_(g) of HTPB systems, providing favorable potentials to replace the conventional plastizers as dioctyl sebacate(DOS) in the HTPB based propellants and explosives.