bluuebunny/crossref_metadata_2025 huggingface dataset:
Time-Dependent Ginzburg-Landau Simulation of Critical Current Density Including z-axis Anisotropy
Authors: Yonezuka Rina , Hamada Yusei , Kamiji Kazunori , Otabe Edmund Soji , Mawatari Yasunori , Matsuno Tetsuya
Published: April 2021

In this study, the three-dimensional time-dependent Ginzburg-Landau equations were numerically solved to visualize the motion of the flux lines in a superconductor under a transverse magnetic field. Pins were inserted into a superconducting rectangular parallelepiped, and the magnetic field dependence of the normalized critical current density Jc
was calculated. Anisotropy yZ of different magnitudes was introduced along the direction of the magnetic field (z-axis). Different pin shapes and orientations were also considered: columnar pins aligned parallel to the direction of either the magnetic field or the current flow, spherical pins, and a planar pin in the field-current plane. For the columnar pins aligned parallel to the field (along the flux lines), J
c showed almost no dependence on yZ. Additionally, a peak in the Jc -B c
urve for this pin geometry was observed at normalized magnetic field, B= 0.4 for all considered yz. In contrast, J
c was dependent on yZ for the columnar pins aligned parallel to the current flow (perpendicular to the flux lines) and the spherical pins. At low magnetic fields (B= 0.1), J
c increased with increasing yZ in both these cases. In the case of the planar pin, J
c showed no dependence on yZ. In conclusion, when a pin was inserted parallel to the normalized magnetic field B, Jc
did not decrease even when the z-axis anisotropy yZ was large.
The Characteristics and Optimal Implementation of Mating Disruption in Managing Pest Insect Population
Authors: Fitri I R , Bakhtiar T , Hanum F , Kusnanto A
Published: April 2021

Conventional pesticide application is the most common method in dealing with pests. However, the application of conventional pesticide has a considerable drawback to the environment and the agricultural sector in the long run. Therefore, a more environmentally friendly pest control method is needed. Mating disruption is one of the alternative methods available. This paper discusses the characteristics and the optimal implementation of a mating disruption using optimal control approach. A generic insect life cycle model is examined and modified to add mating disruption as a dynamic control method. 4th order Runge-Kutta method and forward-backwards sweep method was used to numerically solve the control problem. An illustrative comparison between the implementation of constant control and dynamic control was also given for a variety of scenarios. From the simulations, it was found that mating disruption generates a large amount of benefit when it is fully effective. When it has imperfect effectiveness in disrupting the mating process, mating disruption will generate significantly less benefit. The optimal control approach reduces the application cost significantly while still preserving the benefit.
Differential Game of Pursuit Time Satisfy the Geometric Constraints in l
2 Space
Authors: Waziri Usman , Ibragimov Gafurjan , Usman Abdullahi , Babura Babangida Ibrahim , Adebayo Salaudeed A.
Published: April 2021

In the present article, we present a differential game of pursuit problem with the case of geometric constraint in the Hilbert space l
2. The game is given by system of 2-infinite systems of first order ordinary differential equations (ODEs). Geometric constraint are imposed on the control functions of players. The game is began from a given point z
0 called the initial position. It is given another point z
1 in the space l
2. The Pursuer targeting to bring the state of the system from z
0 to z
1 where an equation to find a guaranteed pursuit time is obtained while that of the Evader action is opposite. The game is assumed to be completed if z(t) = z
1 at some time t. Moreover, a control problem is studied and then extended to the differential game of pursuit where the strategy for the Pursuer is constructed explicitly.
Deriving the Community Readiness Index in Facing the Industrial Revolution 4.0 in Indonesia
Authors: Nurmawiya  , Kurniawan R
Published: April 2021

The demographic dividend that is being experienced by Indonesia is an opportunity to increase the economic growth rate. At the same time, Indonesia has enrolled in the revolution era of industry 4.0, which can provide benefits and boost the Indonesian economy. However, this can negatively impact if the community is not ready, such as increased unemployment due to disruption and job automation. This study examines how ready the Indonesian people are to face the industry 4.0 related to education and the use of information and communication technology (ICT) by forming an index utilizing the factor analysis and then grouping districts based on the index formed. The data used comes from the National Socio-Economic Survey (SUSENAS) 2018 by the Statistics Indonesia (BPS). The results show that there are differences in community readiness based on the groupings formed. This research also shows that in general, Papua and East Nusa Tenggara are not ready to face this era. Therefore, policies are necessitated following each region’s conditions to improve education and ICT, especially Papua and East Nusa Tenggara, which require more attention.
Development of Automated Flight Data Collection System for Air Transportation Statistics
Authors: Panuntun Satria Bagus , Pramana Setia
Published: April 2021

Data and information regarding air transportation is very crucial for all aspects, such as economy, people mobility and tourism. Currently, the Air Transportation Statistics is based on administrative data of different institutions. it is necessary to have a new data source regarding air transportation activities that can be used as an alternative reference for air transportation data which is faster and more granular. This research aims to study a new approach to produce air transportation statistics, especially air transportation statistics in Indonesia from big data that can be used as comparative or as complementary data for official air transportation statistics. This research using a website scraping method from a site that provides monitoring and tracking services for all flights in the world. The flight data was collected daily from the 15 busiest airports in Indonesia for both departure and arrival flights using the API provided by the website. The Scrapy module in the Python programming language is implemented. The data was collected daily from March 15, 2020, to August 31, 2020. The results of the flight data set contain information about the flight code, aircraft code, airline name, departure airport, departure city, arrival airport, arrival city, date/time of departure and arrival, and flight status. The result shows that it is feasible to use big data as a comparative or as a complementary of official statistics, especially in air transportation statistics. By using the web scraping technique, the indicator that usually requires more time and cost can be done in real-time and less cost. This new approach is expected to improve the quality of official air transportation statistics.
Clusterwise Regression Model for Statistical Downscaling to predict Daily Rainfall using Gamma Distribution
Authors: Muthia Nadhira F , Soleh Agus M , Djuraidah Anik
Published: April 2021

This study presents the development of clusterwise regression with gamma distribution and normal distribution. This clusterwise regression model is expected to be a solution for high variance data in order to minimize the error rate in modeling. The first study is simulation of clusterwise regression with gamma distribution and normal-gamma mixture. This simulation is divided into two-cluster and three-cluster simulations with gamma distribution, normal distribution, and mixed normal-gamma distribution with different parameters. The application of clusterwise regression was carried out at four rain stations in West Java, including Bandung, Bogor, Citeko, and Jatiwangi rain stations by first doing variable reduction using principal component analysis.
Analysis of Credit Bank Distribution with Seemingly Unrelated Regression Method on Panel Data
Authors: Jannah W , Sulvianti I D , Indahwati  , Silvianti P , Kurnia A
Published: April 2021

One of the bank’s business activities that most impactful for economic growth is credit distribution that is affected by independent variables including Thirds Party Funds, bank’s performance (CAR and LDR), credit interest rates, NPL, and external variables such as BI Certificate, BI Rate, and exchange rates. Panel data regression is used to analyze the impact of those variables. The type of this research data is combined features of both cross-section and time-series obtained from SPI. The study is aimed to see variables that affect credit distributions at the commercial banks between January 2016 until December 2019. Among the common error structures, there are individual correlations known as contemporaneous correlations. This case can be resolved by seemingly unrelated regression analysis. The result showed that Third Party Funds and LDR have significantly impacted the credit distribution of all types of commercial banks with a goodness of fit measure is 99.909%. Moreover, all variables studied were impact the credit distribution of the Joint Venture Bank and the Regional Development Bank.
Analysis of Residential Property Price Index (RPPI) Using Multi Input Transfer Function
Authors: Chirsty Y , Novita M , Soemartojo S M
Published: April 2021

Residential property or home is one of the basic human needs as a shelter, to be able to continue to live. As the population in Indonesia increases, express the need for residential property will also increase. The movement of residential property prices in Indonesia can be observed from the Residential Property Price Index (RPPI) issued by Bank Indonesia. Residential property prices can be influenced by several factors. For example in economic, the movement of RPPI can be influenced by several factors such as inflation, Composite Stock Price Index (RPPI) and loan interest rates. Forecasting the RPPI can be done with times series modeling. Modeling RPPI using three influencing variables requires a multivariate time series model. The multi-input transfer function model is a multivariate model that can be used in modeling RPPI. In the multi-input transfer function model there is an output series (y

t
) which is the RPPI which is estimated to be influenced by several input series (x

jt
), which are inflation, IHSG and loan interest rates. Based on the model obtained in this study, it can be seen that the prediction of RPPI at the t-time is influenced by the amount of inflation in the previous two months until previous five months, influence by loan interest rates without delay so that it is influenced by the t-time until previous three months, influenced by the IHSG at t-time until previous four months, and also influenced by itself at one month before to four months before.
Performance of SMOTE in a random forest and naive Bayes classifier for imbalanced Hepatitis-B vaccination status
Authors: Putri V M , Masjkur M , Suhaeni C
Published: April 2021

The alternative approach to predict the classification of HB vaccination status is using a machine learning approach such as random forest and naive Bayes classifier. However, for imbalanced classification, the algorithms are biased towards the majority class. To increase the accurate prediction of the classifier, we consider the Synthetic Minority Oversampling Technique (SMOTE) to have more balanced data. The purpose of this study was to compare the performance of SMOTE in the random forest and naive Bayes classifier for imbalanced Hepatitis-B vaccination data. The study used the National Socio-Economic Survey data in 2017 for Aceh province with 2264 cases and 14 variables. The results show that the application of SMOTE in the random forest and naive Bayes classifier improves the accuracy of identification of Hepatitis-B non-vaccination status by 30.08% and 26.09%, respectively, compared to non-SMOTE. Random forest with SMOTE is the best model for classification HB vaccination status. The most important factors that influence the Hepatitis-B vaccination status of Aceh province are the mother’s last education, mother’s occupation, father’s occupation, father’s previous education, and the number of health facilities.
Preparing a Big Data Utilization Communication Strategy
Authors: Faris M , Pramana S
Published: April 2021

Covid-19 pandemic has brought lot of changes to the world, including data production. In this pandemic situation, conducting surveys and censuses in conventional way becomes too risky. However, the community’s need for data is even greater as the public indeed has a great interest in monitoring the development of the social and economic conditions affected by Covid-19. Big Data becomes an alternative data source in meeting this need because it can provide a variety of data that we can process into very useful information quickly. The big data utilization for all fields as well as to inform the policy-making becomes very important nowadays. However, to make clear understanding and well public acceptance on the output of big data utilization needs effective communication strategy. There are five concepts to deliver excellent communication on statistics particularly to promote big data, namely extracting and describing insights from the pool of available statistics, market segmentation, forms of communication, channels of communication, and statistical description. This article proposes effective communication strategy to increase public acceptance and awareness on big data through different communication channels by targeting different characteristics of audiences.
Mach number effect on droplet phase angular distribution behind a nozzle under near-wall liquid film outflow with co-current gas flow into vacuum
Authors: Vyazov Y N , Prikhodko V G , Yarygin I V
Published: April 2021

The paper is devoted to experimental study of near-wall ethanol film outflow with high-velocity co-current air flow from sonic and supersonic nozzles into vacuum. Using the developed measurement techniques (droplet phase flow structure visualization, deposition of droplets on paper substrates, spectrophotometry method), the effect of the nozzle Mach number on angular distribution of droplet phase in the central and the peripheral flow regions behind the nozzle exit is established.
Thermal effect on the film of a solution with a volatile component
Authors: Borodina K A , Tatosov A V
Published: April 2021

Interfacial convection is a widespread phenomenon occurring in various fields of technology, including chemical technology. Marangoni convection is of greatest interest in the case of thin liquid films. Phase transitions significantly affect the convective flow by changing the surface tension coefficient. In this work, we study the behavior of a thin film of a binary homogeneous solution when it is heated. A change in the temperature of the free surface together with the escape of the volatile component leads to two opposite effects in the direction of the surface tension gradient. The necessity of taking into account the motion of the volatile component over the solution surface is substantiated, analytical estimates and solutions are obtained.
Comparison of emission concentrations during the combustion of a double hydrate propane-methane at different temperatures in a muffle furnace
Authors: Morozov V S
Published: April 2021

In recent years, more and more attention in the world has been paid to the development of environmentally friendly technology for combustion gas hydrates. In this work, experimental studies of the combustion of a propane-methane double gas hydrate at different temperatures in a muffle furnace of 650 °C and 950 °C were performed. The increase in temperature in the muffle furnace allowed to reduce harmful emissions and reduce fuel loss. With increasing temperature, the CO concentration decreases by 2.2-2.5 times, CO2 from 7-8% to 3-4% and NOX changes by 1.2–1.5 times, which is associated with an increase in the reaction rate. Emissions of NOX gases during combustion of coal-water suspensions are many times higher than the obtained values of NOX concentrations of methane-propane gas hydrates.
Numerical study of the processes of co-combustion of pulverized coal and gas fuel based on nonstationary methods of turbulence modeling
Authors: Kuznetsov V , Dekterev A , Minakov A
Published: April 2021

In this work, a numerical study of the combustion of pulverized coal in a gas flame is carried out on the basis of the proposed mathematical model of combustion processes, using a nonstationary method for modeling turbulence, complex heat transfer and a reduced mechanism for chemical kinetics. The calculation results show acceptable agreement with the experimental data on the main characteristics of the flame, make it possible to qualitatively correctly determine the structure of the dust and gas flow and derive such parameters as the gas composition, the temperature of particles and gas, the degree of carbon burnout, etc.
Simulation of liquid-steam critical flow from a pipe filled with granular layer
Authors: Khramtsov D P , Nekrasov D A , Moshin A A
Published: April 2021

Based on the method of smoothed particles hydrodynamics a computational model of the critical flow of a vapor-liquid mixture from a pipe with a granular backfill has been developed. The dependence of critical mass flow rate from linear dimensions of the work area, the diameter of the grain filling and pipe length was determined. Numerical results were compared with available experimental data and numerical calculation demonstrates consistency with experimental data. Numerical data on the intensity of vaporization by the cross section of a pipe filled with granular backfill at initial values of the mass fraction of steam from 0.05 to 0.2 were obtained. The non-linearity of the vaporization rate during the mixture moving along the pipe with a decrease in intensity when moving along the length of the pipe is shown.
Features of flow and heat transfer near a pair of circular cylinders
Authors: Seroshtanov V V , Vlasov A S , Suchok V V , Zhidkov N A
Published: April 2021

Synchronous flow and heat transfer study of in a single-phase medium is one of the important engineering and thermophysical problems. To solve this problem, the simultaneous use of PIV and gradient heatmetry is proposed. The investigated model is a pair of heated circular cylinders. Constant cylinders’ surface temperature is ensured by heating with saturated steam. The studies were carried out at various Reynolds numbers and inert-tube distance S, ranging from 0.5d to 4d. The use of gradient heatmetry made it possible to estimate the heat flux pulsations at the second cylinder and then, to compare them with the instantaneous velocity fields obtained using the PIV. The distributions of the heat flux and heat transfer coefficient over the cylinder surface were obtained for the range of Reynolds numbers from 4,8 to 48 × 103. The results are consistent with the data of other authors and show the prospects for the proposed methodology. Moreover, the results on the heat transfer augmentation the same models and in the same modes are presented.
Heat transfer enhancement when boiling on finned surfaces
Authors: Vladimirov V Yu , Chinnov E A
Published: April 2021

In this work, we studied the effect of radial surface finning and hydrophobic fluoropolymer coating of finned surfaces on the intensity of heat transfer at boiling. Two samples were used: 16 fins and 32 fins. At first, experiments were carried out without a hydrophobic coating. After that, the samples were covered with a layer of fluoropolymer and a series of experiments were carried out. During these experiments, the state of the fluoropolymer coating was analyzed. Experiments on a sample with 16 fins showed that deposition of fluoropolymer leads to significant intensification of heat transfer. For the sample with 32 fins, the opposite effect was observed: hydrophobization negatively affected the efficiency of heat transfer. Maximal enhancement of heat transfer, in comparison with finely finned and smooth surfaces, was achieved on a surface with large fins coated with fluoropolymer.
Computational study of enhanced oil recovery from a porous medium using nanosuspension
Authors: Guzei D V , Ivanova S V , Platonov D V , Pryazhnikov A I
Published: April 2021

The paper presents the results of direct numerical simulations of the process of oil displacement by nanosuspension with SiO2 particles from two-dimensional micromodels of a porous medium with different values of permeability. In the calculations, the experimentally measured values of the interfacial tension coefficient and the contact angle of wetting were used. The calculations were performed for pure water and a suspension of silicon oxide nanoparticles with a mass concentration of 1%. The computational study was performed using the VOF method. The influence of the displacement fluid flow rate, nanoparticle concentration and core permeability on the efficiency of oil displacement by nanosuspension was studied. As a result of the work, it was shown that the use of nanosuspensions makes it possible to increase the oil recovery factor. It is shown that with an increase in the mass concentration of particles, the value of the oil recovery factor increases.
Simulation of cuttings removal processes in the horizontal well
Authors: Zhigarev V A , Pryazhnikov M I , Matveev A V , Guzei D V , Shebelev A V
Published: April 2021

The paper presents the results of a numerical simulation of the process of cleaning the annulus of a horizontal well. The effect of the cuttings particle size on the efficiency of cuttings removal from the annulus of the well was studied. The geometry of a real well was used as the calculation model. Cutting particles with sizes from 2 to 5 mm were considered in the numerical study. Velocity profiles of the solid phase (cuttings particles) in annular channels were obtained in the course of conducted numerical simulation.
Heat transfer at a single drop impingement on liquid–vapor–solid triple contact line
Authors: Gigola T G , Cheverda V V , Karchevsky A L , Kabov O A
Published: April 2021

In the current study an experimental investigation of heat transfer at a single drop impingement on liquid-vapor-solid contact line of a liquid layer located on a heated substrate has been performed. The heated thin foil technique is used for experimentation. The interaction dynamics of a drop with a contact line is considered with the help of high-speed visualization and infrared thermography. The obtained experimental data will be processed by solving inversed Cauchy problem for the non-stationary heat transfer equation. The effects of the drop impingement height on the heat flux in the region of the contact line will be determined in the further steps of research.
Minimum and maximum size of levitating water droplets above the surface of a heated liquid layer
Authors: Zaitsev D V , Shatekova A I , Pukhovoy M V
Published: April 2021

This work is devoted to the phenomenon of levitation of liquid microdroplets above hot liquid interfaces. The droplets levitate due to air-vapour upward flow from the liquid surface and grow in time due to condensation. It was found that the diameter of droplets linearly increases with time. The maximum possible and minimum possible droplet sizes were measured depending on the substrate temperature.
Experimental study of the effect of electric discharge on carbon fiber
Authors: Zakirov J U , Kayumov R R , Khazeev K I
Published: April 2021

The results of experimental studies of the effect of an electric discharge on carbon fiber in the discharge voltage range U = 0.2 - 1300 V and at a current I = 0.03 - 1.8 A, at atmospheric pressure are presented. Some features of the combustion of an electric discharge with liquid electrodes are revealed. Some features of the effect of an electric discharge on carbon fiber have been established.
Comparison of initial pressure distributions in shock wave simulation of optical breakdown on surface
Authors: Sattarov A G , Sochnev A V , Ziganshin B R
Published: April 2021

In this work we investigated the velocity of propagation of a shock wave after optical breakdown on the surface, depending on various initial pressure distributions which are simulated in Ansys Fluent. When setting of the shock wave energy of the order of 10 … 20% of the laser pulse energy, results are in satisfactory agreement with experiments. An analysis of the experimental data showed an effect when the velocities of shock waves propagation are comparable but energies of laser pulses differ by two orders of magnitude between each other, which leads to significant deviations from the theory of a point explosion.
Numerical study of the effect of gravitational sedimentation of large particles on the propagation of a shock wave from a homogeneous gas into a polydisperse gas suspension
Authors: Tukmakov D A , Tukmakova N A
Published: April 2021

The effect of the nonuniform concentration of one of the fractions of a two-fraction gas-suspension on the parameters of a shock wave moving from pure gas to a gas-suspension is numerically studied. The motion of a direct shock wave in a two-fraction gas suspension was simulated. The finely dispersed fraction of the gas-suspension had a uniform initial mass content, while larger particles had a nonuniform initial mass content along the y coordinate. It was revealed that in the case of a uniform concentration of all fractions, the shock wave in the channel propagates at a lower speed. It was also found that a nonuniform concentration of the larger particles fraction along the y coordinate affects the spatial distribution of the gas velocity.
Features of a gas discharge with a liquid electrolyte cathode in an extended discharge gap
Authors: Tazmeev K K , Tazmeev A K
Published: April 2021

A gas discharge in an extended gap between a liquid electrolyte cathode and a copper anode was studied experimentally. The discharge was obtained in an open air atmosphere at a distance of 2-18 cm between the electrodes. It was revealed that there are combustion modes with a homogeneous and inhomogeneous plasma column. The electrical properties of the discharge in these two combustion modes were studied. The electric field strength in the plasma column was determined by varying the length of the discharge gap.
Synthesis of semiconductor nanostructures in an argon arc
Authors: Timerkaev B. A. , Kaleeva A. A. , Petrova O. A. , Suleymanov R. M. , Sorokina A. R. , Ibragimov I. S. , Saifutdinov A. I.
Published: April 2021

In this paper, the synthesis of semiconductor spherical nanostructures is carried out by the plasma-chemical method. The sizes of the obtained nanospheres range from 100 nm to 1 mm. These structures are open on one side, have thin walls with a thickness of several nanometers, which end with “tentacles” with a diameter of several nanometers. Since the synthesis involved three elements of the fourth group of the periodic table (germanium, silicon, carbon), it has not yet been possible to determine the crystal structure of the obtained samples. All three elements are present on the surface of the sample in atomic percentages Ge-2.5%, Si-8%, C-55%. In addition to these elements, oxygen is also present in the spectrum.
Production of silicon coatings by plasma-arc method
Authors: Kaleeva A.A. , Timerkaev B.A. , Petrova O.A. , Shamsutdinov R.S. , Dautov I.G , Mastygin A.V.
Published: April 2021

Silicon coatings consisting of micro and nanopores were obtained by plasma-arc method. An experimental setup was assembled for the synthesis of nanostructures. A number of experiments on the synthesis of silicon nanostructures with changes in parameters such as current, voltage, and pressure in a vacuum chamber were carried out. In the experiments, a molybdenum cathode was used as a substrate for the deposition of silicon nanostructures. Atomic silicon evaporated from the anode. The experiments were carried out in an argon medium at a pressure of about 500 Torus. The current in the experiments is about 8 A, and the voltage is within 80 V. The resulting coatings with silicon nanostructures will increase the active surface area by several tens of times.
In search of optimal mode of plasma polishing of surface of agricultural machinery parts when using a discharge with liquid cathode
Authors: Tazmeev B K , Tsybulevsky V V , Tazmeev G K
Published: April 2021

The process of plasma polishing using a gas discharge with liquid electrolyte cathode was studied. The search for optimal modes was carried out by the method of multi-dimensional experiment. The heat flux density and interelectrode distance were considered as the main factors.
The influence of a supersonic flow of gas at glow discharge
Authors: Shamsutdinov R S , Timerkaev B A
Published: April 2021

Experiments have been carried out to study the effect of a supersonic gas flow on a transverse glow discharge in the case when the supersonic gas outflow enters the region of Faraday dark space, i.e. the positive column ends before reaching the supersonic jet. And also in the case when the supersonic outflow of gas falls into the region of the positive column. It is established that the organization of the supersonic flow changes the glow pattern of the glow discharge, creating a spatial inhomogeneity in the interelectrode space.
Features of the process of laser welding of cast iron with steel
Authors: Zvezdin V V , Rakhimov R R , Khisamutdinov R M , Portnov S M , Saubanov R R
Published: April 2021

The article presents the results of research on laser welding of cast iron with steel on a robotic laser technological complex. A system of technical vision for precision focusing of laser radiation on the joint of welded elements is presented, which provides control of the movement of the laser beam along the welded joint and adjustment of the radiation power, depending on the temperature of the joint. The welding process is carried out in a protective atmosphere of inert gases. Rough guidance of the beam is carried out by the robotic complex until the point “start of welding” falls into the field of view of the technical vision system, which is built into the process head. Precision positioning of the beam focus on the seam is provided by turning the focusing lens to a certain angle by a piezo actuator. The results of metallographic studies of the welded seam of cast iron and steel are presented.
Development of a Thermographic Vibratory Test Bench for Predictive Maintenance in Asynchronous Motors
Authors: Vilchez K , Perez E , Coaquira C , Hernandez J , Carmona J
Published: April 2021

The predictive philosophy contributes to improving productivity, reducing system failures and reducing unplanned downtime in a non-invasive way to the machine, for which the test bench is based on the German standard VDI2221, using mathematical models to select the materials and the design of the final prototype. The development of the project consists of applying vibration analysis, thermographic analysis and the quality of energy in which each measurement and the correlation that exist between them is shown; in addition, the inverse Fourier transform was used to demonstrate the amplitude and frequency ranges according to the theoretical equation proposed in the Matlab program, it can also be seen the higher order vibrations of 22.1 is located at the same critical point of the SP7 measurement with a temperature of 34.6 ° C and an emissivity of 0.95, likewise the Power quality measurements are within the allowable limits according to ISO 50001; On the other hand, this analysis made it possible to determine the existence of a positive linear correlation between thermography and vibration analyzes with a correlation coefficient equal to 0.828.
Wear Mechanism and Failure Analysis of A High-speed Train Hydraulic Damper Using CFD Approach
Authors: Wang Wenlin , Huang Bao , Zhou Zirong , Du Jianming
Published: April 2021

To evaluate wear-induced hydraulic damper failures, wear mechanism of a Chinese CRH train hydraulic damper by invaded dust and sand particles under vibration conditions is firstly analysed, CFD modelling of the working chamber of the damper is then carried out and fluid dynamics analysis of the damper under different vibration speed input conditions is performed. The CFD results demonstrate that under wear conditions both the fluid discharge speed and produced pressure would drop significantly, the maximum fluid discharge speed and pressure are far smaller than that under non-wear conditions, the damping force would have a maximum decrease of 62.3%. The wear mechanism, CFD model established and analysis results obtained in this study can be used for further railway hydraulic damper evaluation and optimal designs.
A Multi-error Measurement Method for Workpiece of Vertical Machine Tool
Authors: Wang Xiaoming , Wan Daowen , Liu Yongmeng , Wang Dawei , Cao Zifei , Wang Junfeng , Sun Chuanzhi , Zhou Dong , Chen Xue , Ma Hongliang
Published: April 2021

This paper proposes a method of multi-error separation for online monitoring of machine tool workpieces based on a single sensor with three rotation. Firstly, the multiple error sources what include roundness error, spindle radial rotation error and eccentric error are identified in the measured data of the sensor. Then, a multi-error separation model is established based on error sources. And the accurate separation of each error is realized through theoretical derivation. At the same time, an experimental system is set up to further verify the effectiveness and accuracy of the model.
Design of the New Locking Mechanism of Lock-iron Deflection Type and Dynamic Simulation
Authors: Yan-fu SUN , Jian-yu ZHU , Sheng-Jie CI
Published: April 2021

Rotary rigid locking mechanism It has the characteristics of reliable function, simple structure and it can shoot more powerful cartridge. Hence, it is universally utilized in the gun family which was developed independently by China. At present, the research level of rifle weapon locking mechanism structure has been significantly improved, but the research on dynamics simulation is still relatively few. To improve the research on the dynamics of the locking mechanism. Established the 3D model based on UG and selected locking block as the research object, established the dynamics differential equation of the locking mechanism through the dynamics analysis and make simulation on the model by using the ADAMS. The results show that the locking mechanism can be completed the unlock within 0.5 minute and lock within 1 minute, the motion characteristics of the recoil and reentry proved that the locking mechanism is coordinated, and the locking is reliable and went well. Dynamics differential equation of the locking mechanism of lock-iron deflection type provides a certain theoretical basis for the design of the automatic weapon locking mechanism.
A Health Monitoring Method of Machine Tool Spindle Based on Multi-domain Analysis and Convolutional Neural Network
Authors: Wang Xiaoming , Wan Daowen , Liu Yongmeng , Wang Dawei , Cao Zifei , Wang Junfeng , Sun Chuanzhi , Zhou Dong , Chen Xue , Ma Hongliang
Published: April 2021

This paper presents a method for monitoring machine tool spindle health based on multi-domain analysis and convolutional neural network. By extracting the characteristics of data from time domain, frequency domain and time frequency domain, the data information is fully excavated automatically. Meanwhile, Convolutional neural network is used to realize fault diagnosis and classification. As a result, the fault classification results reveal high accuracy by datasheet. It proves that the method in this paper which has strong practicability and application value.
Mechanical Displacement for 3D Printers’ Parts Using FEM as Inverse Engineering Method in Honduras
Authors: Luis Ordoñez Avila Jose , Elena Perdomo Maria , Yanire Rivas Bejarano Mildred , Luis Ordoñez Fernández Jose
Published: April 2021

Plastics industry is growing day by day; the new techniques generated by the fourth industrial revolution, such as additive manufacturing (AM) or better known as 3D printing, make the design and production of plastic products available to all. The aim of this research aims to explore the application of reverse engineering in improving the mechanical displacement in AM. The method used in this paper was the finite element analysis (FEM) applying it to different 3D printing parameters with a grid infill. Then the multiple line regression (MLR) was implemented to determine parameters relation. Finally, the simplex method to improve the parameters to decrease the mechanical displacement in AM. Reverse engineering process for parts that use 0.2 as shell wall and 25% of grid infill can have acceptable mechanical performance to be used in different applications.
Nonlinear Responds of Lamb Waves in Plate Structure with Micro-Crack Using Frequency-Mixing Technique
Authors: Zhan Zaifu , Wang Fuping , Zheng Yang , Wang Zhe , Huang Songling , Li Xincheng , Wang Shen
Published: April 2021

Lamb waves have huge potential in non-destructive testing. Its nonlinear responses provide a promising method to detect micro-cracks. This work mainly analyses nonlinear responses of two Lamb waves with different frequencies in plate structure with micro-cracks. The interaction between ultrasound and two types of cracks with different lengths, widths, angles and number was performed using finite element simulations. From the results, it is shown that frequency-mixing technique is sensitive to the micro-cracks. Also, different parameters of cracks have different relationships with sum-frequency harmonic amplitudes. These relationships provide basic support for quantitative evaluation of cracks.
Research on a Passenger Aircraft Flight Control System Gain Scheduler Design
Authors: Guo Wei
Published: April 2021

This paper employs the mathematical model of a passenger aircraft for the purpose of designing longitudinal flight control law to satisfy handling qualities assessment. Aircraft Rate Command Attitude Hold (RCAH) controllers are designed at the specific equilibrium points in the flight envelope by means of a state space pole placement design procedure. The handling qualities assessment of the aircraft is presented, based on which the gain scheduler is designed. The existing criteria are employed to assess the handling qualities of the aircraft augmented by the gain scheduler, including the Control Anticipation Parameter (CAP) and Neal and Smith. The augmented aircraft performs satisfactorily and meets the requirement of handling qualities.
Simulations and Ground Experiments of Interior Noise for Space Station Module
Authors: Yang Jiang , Feng Gousong , Wang Dong , Zhang Jungang , Li Xinming , Liu Chuang
Published: April 2021

China Space Station (CSS) module is currently under construction. Considering astronauts will be working and living on orbit for several months, a comfortable acoustic environment in manned space station must be provided. This paper investigates the interior noise effects for CSS using two typical vibro-acoustic analysis methods, that is, coupled finite element/finite element method (FE/FEM) and statistical energy analysis (SEA) method. The simulation models are validated through ground experiments by the noise test for space station simulation module. The combination of the above two methods can well predict the acoustic levels for both low and high frequencies. A ground experiment scheme for interior noise of space station module is also proposed on the basis of its noise characteristics. Sound power equivalent method is utilized to simulate a single noise source and multi-input multi-output (MIMO) closed-loop control method is employed for multiple noise sources. It is shown that the sound field simulation results are in perfect agreement with the simulation requirements of noise sources.
Modelling and Experimental Validation of the Dynamic Damping Characteristics of A High-speed Train Hydraulic Damper
Authors: Fan Youquan , Zhu Shan , Wu Yongming , Wang Wenlin
Published: April 2021

Aiming to understand the effects of damper parameter on vehicle system dynamics in the context of railway vehicle system design, a full parametric damper model, which includes the complete valve system dynamics, the dynamic force equilibrium equation, the flow continuity equation, the flow losses model and the comprehensive stiffness model, is established in this work. Both numerical simulation using the established damper model and bench test of dynamic performance of the damper are carried out, the comparison shows that the maximum relative error between simulation and bench test is only 2.6%, in addition, the rates of asymmetry are near and both small. Therefore, the simulation result agrees well with the test result, the established full parameter damper model is validated, the model would be accurate in predicting damper parameter effects in further high-speed train dynamics research and vehicle design.
Thermal Performance of Vapour Chamber in Different Tilting Configurations for Battery Liquid Cooling System
Authors: Li Weiping , Li Longjian , Cui Wenzhi , Guo Mengting
Published: April 2021

Vapour chamber is a planar heat pipe and has been widely used in the thermal management of electronic device. In this work, a grooved aluminium vapour chamber was presented with a one-through cooling plate to develop a simplified and practicable battery liquid cooling system. The impact of filling ratio and tilting configuration on the thermal performance of vapour chamber was experimentally investigated. The results showed that the thermal resistance of the vapour chamber increased gradually with the increase in filling ratio, and there was a deterioration of the heat transfer in tilting configuration. However, the vapour chamber at 20% filling ratio had a better performance at positive tilting angle configuration compared with that at negative tilting angle configuration. Moreover, the temperature distribution of the heating surface is fairly uniform with the application of the vapour chamber. Despite the temperature rise of the cooling water in the cooling plate up to 3.8ºC, the minimum temperature difference of the heating surface could be kept within 1 ºC and the minimum thermal resistance could be kept within 0.075ºC/W. The results indicate that the temperature difference of the heating surface can be suppressed through the heat and mass transport of phases inside the vapour chamber.
Numerical and Experimental Analysis of Subsonic and Transonic Base Pressure
Authors: Xiaobing Wang , Binhua He , Hong Zhang , Zhongliang Zhao , Yuping Li , Jianzhong Chen
Published: April 2021

Base drag of space vehicles with large, truncated base usually forms a considerable component of overall drag. The base drag is usually difficult to be accurately predicted due to the intrinsic complexity of base flow. The subsonic and transonic base pressure characteristics were studied by large scale wind tunnel test and Reynolds-Averaged Navier-Stokes/Large Eddy Simulation (RANS/LES) hybrid numerical simulation. The test results show that interferences of both tail sting and ventral blade varies evidently with Mach numbers. The RANS/LES hybrid method was proved to be effective as the calculated time-average base pressure and base drag agree well with wind tunnel test, and detailed flow structures were successfully captured. The base flow pattern is complicated in sub- and transonic regime that either single support scheme is not sufficient to obtain an accurate measurement of base drag. Various support schemes and high precision numerical method are recommended in similar studies.
Experimental Investigations of the Flow through Slotted Wall in Transonic Wind Tunnel*
Authors: GUANGYUAN LIU , DAWEI LIU , QIUTING GUO
Published: April 2021

Experimental study of the flow through slotted wall was conducted in 0.6m transonic and supersonic wind tunnel. Transverse flow properties, such as flow angle, pressure, velocity components were measured using travelling probe, and distributions of Mach number, total pressure recovery were acquired for both empty tunnel and airfoil model cases. Shear layer thickness was calculated based on test results. Results showed that, transverse velocity from shear layer through slot into plenum chamber is approximately linear, and wall shear layer thickness was up to 3 to 4 times slot widths on slot center plane, and homogeneous boundary conditions were inaccurate.
Geotechnical Characterization and Applications of Riyadh Metro Tunnel Boring Machine Excavated Material (TBMEM)
Authors: Alnuaim Ahmed
Published: April 2021

The Riyadh city is witnessing one of the most significant infrastructure projects in its history. The 22.5 billion dollars and 180 km in total length Riyadh Metro project will be constructed using different tunnelling methods: 10 m diameter tunnel boring machine (TBM), cut and cover, and new Austrian tunnelling method (NATM). About 35 km will be constructed using 10 m diameter TBMs, which will produce approximately 2.8 million cubic meters of TBM excavated material (TBMEM). Transferring such an amount of material will cause a severe impact on the environment and traffic as it required many trucks to transport the material to a remote site. The comprehensive geotechnical characterization profile of the material was prepared in order to understand the performance of the material and identify the areas in which the material can be utilized. In addition, this paper will explore the potential of using TBMEM after being treated and mix with clean sand to enhance its geotechnical characteristics. Several potential areas to utilize the TBMEM will be presented. Furthermore, the project will investigate the applicability of TBMEM to be used as backfill material and to what extent the treatment should go to achieve a mixture that meets the standard requirements.
Installation of a heavy king pile using driving guidance
Authors: Beuße Jannik , Grabe Jürgen
Published: April 2021

Combined walls are built out of heavy king piles and lighter sheet piles to protect site jumps up to 30 m of quay walls. Few recommendations exist on how to install the king piles so that the sheet piles can absorb the deformations coming from the location slippage of the king piles. As such the installation process of king piles needs to be regulated. By measuring the installation process on a construction field in Rostock in Germany, the dynamical influence on the king pile’s position at the end was investigated. For that purpose, a large king pile with a length of about 30 m was equipped with acceleration, strain and inclination sensors. The driving guide and the installation machine were equipped with acceleration sensors as well. The data was saved with a frame rate of 200 kHz. Next to these analogical sensors the hole driving process is visually recorded by a high-speed camera and a drone. The movement of the king pile during driving derived from the measurement data and compared with the numerical video analyses. The influence of the driving guide was then analysed. Further, the end position of the king pile was measured with an inclinometer.