bluuebunny/crossref_metadata_2025 huggingface dataset:
Progressive Failure Analysis and Experiment Research of the Composite Bolted Connection
Authors: Xi Li , Yazhi Li
Published: March 2021

Bolt connection is a common engineering structure. In order to analysis the composite bolted connection, based on continuous damage mechanics method, different failure criteria are established for fiber, matrix and delamination. To improve the efficiency of engineering estimation, this paper proposed the selective parabola algorithm to solve the fracture angle and uses the linear stiffness degradation method to establish the finite element model. Firstly, composite laminates with a hole in the tension stress are analyzed by using the above model, and by comparing the test results with the experimental results, the feasibility of the model is verified. Then, the progressive failure analysis is carried out to study the composite bolted connection. The comparison between the calculation results and the test results shows that the mechanical model proposed in this paper can predict the strength of composite bolted connection under tensile load accurately and also can present the damage evolution process exactly.
Research on Protection Optimization of Distribution Network Containing Distributed Power Generation Based on Sparrow Algorithm
Authors: He Yu-Hua , Luo Yi , Li An-Hao , Wang Teng-Fei , Cheng Zhe , Peng Yan-Hua
Published: March 2021

In recent years, the increasing energy crisis and environmental pollution have brought attention to distributed renewable power generation such as photovoltaics and wind power. However, the integration of distributed power sources puts forward higher requirements for the safety, stability and economic operation of the power system. Traditional protection setting methods face greater difficulties in solving the contradiction between action time and protection selectivity under complex conditions including distributed power generation. In many cases, the setting value is not optimal. With the increase in the penetration rate of distributed power sources and the increasingly complex operation of distribution networks, how to achieve the optimal setting of overall protection performance has become a current research hotspot. For this reason, this paper proposes a new scheme based on the Sparrow algorithm to optimize the online protection of distributed power distribution network protection, which is verified by a calculation example.
A method for geometric tolerance annotation and position adjustment of engineering graphics
Authors: Jiang Youzhi , Liu Fuyun , Wu Qiang , Xu Yunzhan
Published: March 2021

In the field of engineering design, 2d engineering drawing is the core content of machining. Most drawings are datum symbol old mark phenomenon, manually modify the notation and variant design can lead to the emergence of the form tolerance of interference, using CAD software provided by the API interface, combined with the Microsoft visual studio 2012 development platform for secondary development, makes the old national standard in the engineering drawing, form and position tolerances of interference is able to automatically adjust and modify the notation, and meet the international requirements. It can not only shorten the design cycle and improve the drawing efficiency of designers in product production, but also avoid the human error in drawing and ensure the quality of drawing.
Morphology and Efficiency of the Deposition Function in the Deterministic Electrochemical Repairing Method
Authors: Li Dan , Yin Qin , Shen Xinmin , Yuan Jianhu , Zhang Xiaonan
Published: March 2021

Deterministic electrochemical repairing method is effective technique for the rapid fixing of damaged parts in the military equipment, and its critical content is to achieve a steady deposition function. In order to take into consideration both the repairing efficiency and fixing accuracy, three shapes of deposition functions were developed through the square nozzles, the rectangular nozzles and the round nozzles. Meanwhile, for the three kinds of nozzles, each kind had several sizes, which aimed to further improve the scope of application of the deterministic electrochemical repairing method. Furthermore, the deposition functions were detected through measuring the morphology and efficiency of the deposition spots obtained by the deterministic electrochemical repairing system with the varied deposition times of 0.5h, 1.0h, 1.5h and 2.0h, respectively. The experimental results indicated that morphology of the deposition functions were consistent with those theoretical results, and their corresponding efficiency was steady, which were propitious to obtained better repairing efficiency and higher fixing accuracy. The developed effective deposition functions can promote the practical application of deterministic electrochemical repairing method in the precision assurance of military equipment.
Automatic Control System of Hydraulic Tension Pilot Warm Rolling Mill
Authors: Yang Hong , Li Jianping , Sun Tao , Niu Wenyong
Published: March 2021

In order to meet the warm rolling demand and deal with the inefficiency of cold-rolled deformation metals such as high-strength steel, silicon steel and magnesium-nickel alloy, etc., The state key Laboratory of Rolling technology and Automation of Northeastern University(NEU-RAL) designed and manufactured a new pilot warm rolling mill that can achieve heating on line in the rolling process. This paper introduces equipment constitutes, and its main functions and features. The paper also describes its temperature control system, AGC system and ATC system during the warm rolling process in details. Multiple experiments have proven that the pilot warm rolling mill can not only simulate the actual production process to produce the hard-deformed metals, provide innovative technology, but also offer easy to use experimental equipment for steel industry researchers.
Simulation and optimization of a factory automation production line based on Plant Simulation
Authors: Luo Silin , Cen Songqing
Published: March 2021

Model an automated production line in a factory in order to understand and improve the automated production line. The layout and function of this automated production line were simulated on Plant Simulation, and the statistical results were obtained according to the actual situation. According to the results, the shortcomings of the production line were analyzed, an optimization method was proposed, and the results were simulated again by using genetic algorithm for comparison.
Industrial robot trajectory planning based on improved pso algorithm
Authors: Han Shunjie , Shan Xinchao , Fu Jinxin , Xu Weijin , Mi Hongyan
Published: March 2021

A particle swarm optimization (PSO) algorithm which can dynamically adjust learning factors is proposed to solve the problems of low efficiency and unstable operation of traditional industrial robots. The method uses piecewise polynomial interpolation to fit the trajectory, and uses an improved particle swarm algorithm to optimize the trajectory of industrial robots with time as a fitness function. This method effectively combines the piecewise polynomial interpolation function with PSO, avoids the complex process of particle swarm algorithm to construct the adaptation function, and improves the problem that the traditional PSO is more likely to fall into local extreme value in the early stage and convergence speed is slow in the later stage. Through experiments to obtain the motion pose, velocity and acceleration trajectory of each joint of the manipulator, we can know that this method can effectively realize the trajectory optimization of the industrial robot, and ensure the stability of the overall operation while improving the operating efficiency.
RF design studies on a 325 MHz rebuncher cavity for high intensity linear accelerators producing neutrons
Authors: Zhu X. , Marchand C. , Piquet O.
Published: March 2021

Two identical Coupled Cavity Linac type (CCL) rebuncher cavities to be integrated in the Medium Energy Beam Transport line (MEBT) of a high intensity linac Accelerator have been studied for matching a 40-mA proton beam accelerated by a 3 MeV Radio-Frequency Quadrupole (RFQ) to a 13 MeV Drift Tube Linac (DTL). The rebuncher operates at 325 MHz, and is designed for β = 0.080. The rebuncher aperture radius is 20 mm required by transverse beam dynamics. It is a single gap structure operating in the TM_010 mode for providing longitudinal beam focusing. The unloaded quality Q0 and the required input power to achieve an effective voltage of 150 kV are 27253 and 20.5 kW, respectively. In this work, we present the RF design studies for the high power rebuncher resonator, as well as the considerations of the tuning scheme and the coupler design.
Global synthesis for the scaling of soil microbial nitrogen to phosphorus in terrestrial ecosystems
Authors: Wang Zhiqiang , Wang Mingcheng , Yu Kailiang , Hu Huifeng , Yang Yuanhe , Ciais Philippe , Ballantyne Ashley P , Niklas Karl J , Huang Heng , Yao Buqing , Wright S Joseph
Published: March 2021

Nitrogen (N) and phosphorus (P) are associated with the life history of all organisms. Soil microbes play essential roles in nutrient cycling and ecosystem dynamics. As compared to plants, however, our understanding of the soil microbial N versus P scaling relationship remains limited. In this study, we used a comprehensive dataset comprising 2210 observations from 422 sites worldwide to examine microbial C, N, and P concentrations and C:N:P ratios, and to determine the scaling of microbial N versus P in different ecosystems and spatial scales (i.e. soil depths, latitudinal zones, and local sites). The global mean values of microbial C, N, and P concentrations were 721.5 mg kg−1, 84.7 mg kg−1, 37.6 mg kg−1, respectively, whereas C:N, C:P, and N:P ratios were 9.5, 30, and 3.4, respectively. Microbial C, N, and P concentrations varied within and across different ecosystems and spatial scales, but C:N:P ratios varied surprisingly little. The numerical value of the scaling exponent (i.e. the slope of the log-log linear relationship) of microbial N versus P was 0.89 across the entire dataset and for different ecosystems. However, the numerical value of the exponent varied significantly across different spatial scales. Soil total P was the largest contributor to the variation observed in the scaling of microbial N versus P at different local sites. These findings have important implications for predicting soil microbial growth rates and improving our understanding of nutrient cycling in plant-soil-microbe systems.
Research on remote monitoring technology of temperature field in goaf of fully mechanized caving face
Authors: Sun Jing , Zhang Canming
Published: March 2021

In this paper, the test site is the working surface hollowing area of Luling Coal Mine 8, coal seam III 811, and the distributed fiber temperature measurement is carried out. Distributed temperature measuring fibers and beam tubes are arranged in the inlet and return wind lanes of the work surface for continuous monitoring. After analyzing the data such as measuring temperature and gas concentration, the remote monitoring technology of the temperature field in the mining area is expanded. Finally, combined with the self-ignition characteristics of the Luling coal seam and the classification criteria of the “three zones” in the mining area, the range of the self-ignition hazard area of the III 811 mining area is accurately determined. This paper provides theoretical and technical support for the development of targeted fire prevention measures and remote monitoring.
Experimental Study on Spontaneous Combustion Prediction System of No.12 Coal Seam in TongXin Coal Mine
Authors: Cai Zhouquan , Shi Lin
Published: March 2021

To reduce coal spontaneous combustion hazards, establishing accurate and reliable prediction system, with 12# coal seam with TongXin ore as object, using the large platform of coal spontaneous combustion simulation of coal spontaneous combustion process, the oxygen consumption rate, exothermal intensity and other characteristic parameters were analyzed, and based on the method of index gases, temperature programmed experiments, summarizes the characteristics of the temperature and gas change rule. The experimental results show that the oxygen consumption rate and heat release intensity increase with the increase of coal temperature. At 70.1 °C, it reaches the critical temperature of coal; at 132.7 °C, the dry cracking temperature of coal is reached;when the temperature is 244.8 °C, it reaches the growth temperature of coal; when the coal temperature is between 22.9.1-70.1 °C, CO and C2H6/CH4 can be selected as the main index gas of No.12 coal seam in TongXin Mine; when the coal temperature is between 132.7-320.5 °C, CO can be selected as the index gas. Since C2H4 can only be detected when the coal temperature reaches about 85 °C, C2H4 and C2H4/CH4 can be used as auxiliary marker gas.
Integrated energy service business operation model and key issues research and prospects
Authors: Liu Dunnan , Liang Jiahao
Published: March 2021

At the present stage, China is faced with the problems of unreasonable energy consumption structure, difficult coordination of energy utilization and imbalance of energy supply and demand. Under the background of energy Internet, the commercial operation of comprehensive energy services will have a favorable impact on solving the problem of comprehensive utilization of energy in China and stabilizing the balance between energy supply and demand. This paper reviews the current research on the business operation mode of integrated energy service, summarizes the key problems in the business operation process of integrated energy service, and finally draws relevant conclusions based on the above content, and puts forward the improvement of the business operation mode of integrated energy service at the current stage.
Removal of fine particles in coal fired power plant by chemical coagulation
Authors: Zhang Xue-Yan , Xiao Li-Chun , Zhai Xiao-Yu
Published: March 2021

The fine particle dust produced by coal-fired power plants is one of the important sources of air pollutants. Wet electrostatic precipitator (WESP) is one of the effective methods to remove fine particle dust. However, the traditional wet electrostatic precipitator still has low collection efficiency for the superfine particle dust. To improve the collection efficiency and the chemical coagulation method is applied to the wet electrostatic precipitator. Experiments are carried out by varying the chemical coagulation agent type, concentration, surfactant species. The results show that: Adding chemical coagulants can promote the coagulation effect of fine particles, and Xanthan gum (XTG) has the best coagulation effect; the concentration of chemical coagulant also affects the coagulation effect and collection efficiency of dust, the optimal concentration of XTG is 1.0×10−2 g/L; among the surfactants, dodecyl dimethyl benzyl ammonium chloride (1227) has the best effect, and the dust removal efficiency can reach 98.80%. Through experimental exploration, the chemical coagulation method has a good application prospect in wet electrostatic precipitators.
High-throughput sequencing method to study the dynamic changes of microbial communities in second-generation fermented lettuce
Authors: Zhang Yao , Chen Zhidi , Wang Xinyu , Li Qingwen , Gao Xiuzhi , Yi Xinxin , Ma Yumeng
Published: March 2021

Pickle has been loved by consumers since ancient times because of its unique taste, strong flavor, simple process and long shelf life. Complex microbial succession activities promote the fermentation process of pickle. In this paper, high-throughput sequencing methods were used to study the bacterial microbial dynamics of the second-round fermentation lettuce artificially inoculated with Lactobacillus. The results showed that as the fermentation progressed, at the bacterial genus level, Lactobacillus are the dominant genus in the fermentation process. In the late fermentation stage, the dynamic changes of microorganisms tend to be stable. These results provide ideas and new strategies for the development of pickle products using lettuce as the main vegetable raw material.
Study on preparation and treatment of phosphorus removal performance with M/Mg/Al (M=Zn/Co/Cu) hydrotalcites
Authors: Huang Zhiyong , Liu Hongbo , Xu Peiwen
Published: March 2021

A series of M/Mg/Al (M=Zn/Co/Cu) hydrotalcites were synthesized by co-precipitation method. XRD was used to characterize their structure. The results showed that the prepared hydrotalcites samples have typical hydrotalcite structure with high crystalline. The hydrotalcites samples were used as absorbent in the treatment of phosphorus removal of wastewater. Single factor control variable method was used to study the relationship between the conditions such as the type of metal, synthesis condition, preparation method, calcination time, type of absorbent, and the adsorption ability of phosphorus in wastewater. The results showed that Zn/Mg/Al hydrotalcites have better phosphorus removal ability than the Mg/Al, Co/Mg/Al and Cu/Mg/Al hydrotalcites. Zn/Mg/Al hydrotalcites prepared with the metal ratio of Zn/Mg/A=3:1:1, reaction temperature of 75 °C, pH of 11 has the best phosphorus removal effect. After calcained at 300 °C for 4h, the Zn/Mg/Al hydrotalcites has the best phosphorus removal efficiency of 76.6%. Zn/Mg/Al hydrotalcites have much better phosphorus removal efficiency than active carbon.
Research Process on Water Treatment Agent of Boiler for Preventing Metal Corrosion in the Steam-water Cycle
Authors: Zhao Zhijuan , Peng Yunyan , Jin Dong
Published: March 2021

The safe and economical operation of boiler is influenced significantly by the metal corrosion in the steam-water cycle. It is the most common way to add the water treatment agents into the boiler water to prevent metal corrosion. In this paper, the application situation and limitations of the traditional boiler water treatment agents were summarized. Then the research process of the film-forming amines was elaborated. First, the structure and composition of film-forming amines, their properties and the interaction mechanisms with metal materials were described. Second, the industrial application of the film-forming amines was considered. Third, the existing problems of film-forming amines were discussed. Finally the future development of the novel film-forming amines was prospected.
The effect of periodic porous Al on the heat transfer performance of paraffin
Authors: Deng Xing , Liu Fei , Zhang Zhengwen , Zhang Tao
Published: March 2021

In order to enhance the heat transfer performance of paraffin, periodic porous lattice structures was designed by triply periodic minimal surface method and formed by selective laser melting(SLM) technology as the heat conduction enhancer of paraffin. Porous Al/paraffin composite phase change materials(PCM) with were prepared by dipping and a phase change heat storage experiment platform was built to study the effect of periodic porous Al structure on the heat transfer performance of paraffin. The results show that the melting characteristics of the paraffin have been significantly improved with the periodic porous Al structure embedded in. The melting rate is greatly increased, the melting time is shortened by more than 61.7%, and the internal temperature gradient during melting is reduced by 41%.
Compared with rubber and amalgam materials, pure titanium materials have advantages in dental prosthesis development
Authors: Jin Huang
Published: March 2021

Prosthodontics is the most common problem in Chinese dentistry. So far, most dental prosthetics in China are made of rubber and metal fillers. However, the fillings made of these two materials are prone to frequent dental fillings and complex operation process of root canal fillings. Amalgam metal filler is easy to cause safety hazards. It’s also acidic. The effect of amalgam on blood circulation can further lead to a decrease in immunity. In this paper, the application of pure titanium in the oral cavity can reduce the problems caused by rubber and metal materials. At present, the difficulties encountered in the study are obvious burning sensation, severe heavy metal smell and significant pain. Only by solving the existing problems can the development of pure titanium make progress.
Study on the changes of chemical constituents of Pueraria lobata during fermentation
Authors: Li Zhenxing , Shan Xuemei , Song Ying , Gao Yuan
Published: March 2021

At present, Pueraria lobata has become an important raw material in the field of health food and medicine, and research on its processing has gradually increased. As a result, Pueraria lobata fermentation technology has also been further researched and expanded. Based on this, this article discusses the fermentation of Pueraria lobata from a chemical point of view, and discusses in detail the changes of the main constituents as well as the change mechanism, in order to provide references for similar work in the future to improve the quality of the fermentation products of Pueraria lobata.
A ML framework to predict permeability of highly porous media based on PSD
Authors: Yang Haoyu , Ke Yan , Zhang Duo
Published: March 2021

Using machine learning (ML) method to predict permeability of porous media has shown great potential in recent years. A current problem is the lack of effective models to account for highly porous media with dilated pores. This study includes (1) generation of media (porosity = 0.8) via a Boolean process, (2) the pore size distribution (PSD) control by using different groups of homogeneous packed spherical particles (3) PSD data obtainment using the spherical contact distribution model (4) computation of the permeability via LBM simulations, (4) training of artificial neuron network (ANN) and (5) analysis of the model. It is found that the PSD could outperform the previous geometry descriptors as an input of ML framework to deal with highly porous structures with different fractions of dilated pores, however there is still room for precision enhancement.
Screening and Array Optimization of Metal-Oxide-Semiconductor Gas Sensing Materials
Authors: Yang Shu , Gao Shi , Wang Xuefeng , Qian Tingbi
Published: March 2021

Metal-Oxide-Semiconductor(MOS) based gas sensor is considered to be a promising method for harmful gas detection, but the detection usually needs to meet the conditions of excellent selectivity, high responsivity, quick response, low power consumption, low detection concentration limit, etc. To improve the performance of the sensor, materials need to be screened and array need to be optimized. This paper will briefly introduce the research on MOS gas sensing materials screening and array optimization.
Study on Air Quality Monitoring and Numerical Simulation Optimization in Shenyang Metro Station
Authors: Hao Hong , Song Xinyi , Zhang Yidan , Zhang Hailong
Published: March 2021

Air quality monitoring was carried out at the three stations A, B and C of Line 1, Line 2 and Line 9 of Shenyang Subway station. CO2, formaldehyde, TVOC and PM2.5 were selected as pollutants. The results indicate that because the platform floor is far from the ground and there is almost no natural ventilation, the concentration of pollutants is higher than that of the station hall floor. The formaldehyde concentration of the newly built site A exceeded the standard by 37.1%. CFD was used for numerical simulation, and the section with human respiratory height Z=1.5m was selected as a typical section. The cloud map of temperature, velocity and concentration distribution of typical pollutants were analyzed to find out the areas where the concentration of pollutants exceeded the standard and analyze the reasons. The layout of tuyere which can improve the air quality in subway station is proposed, and the simulation and optimization research is carried out.
Optimization Study on Gas Control of Coal Preparation Plant Bunker
Authors: Chen Bin
Published: March 2021

According to Zhao Zhuang coal mine coal preparation plant of coal field, this paper adopt methods of theoretical analysis, monitoring and test research, studied the distribution of gas migration regularity and optimized the structure of coal preparation plant bunker. Adopt the natural ventilation system to replace the original coal power fan system, effectively controlled of the coal gas concentration below 0.5%, and obtained the good effect of gas control, and created the better economic and social benefits. This study is of great significance to the control of coal bunker gas in other mining areas.
Influence of porosity on the fatigue behaviour of welded joints
Authors: Livieri P , Tovo R
Published: March 2021

In this paper, the influence of a single pore on the fatigue behaviour of welded joints has been examined by means of the implicit gradient approach. The pore has been considered a stress raiser that interacts with the weld toe or weld root. As an example, in the case of a cruciform joint with a load-carrying fillet weld, the influence of a single spherical pore is examined. Furthermore, the fatigue behaviour of an aluminium laser welded joint with ellipsoid equivalent pores is considered and a comparison is made with the fatigue strength of an aluminium arc welded joint.
Thermal Insulation Performance Optimization of Hollow Bricks Made up of 3D Printable Rubber-Cement Mortars: Material Properties and FEM-based Modelling
Authors: Sambucci M , Valente M
Published: March 2021

Sustainable construction is attracting more attention lately. It involves the design of eco-friendly building structures, the reduction of energy consumption and waste, the use of renewable and recyclable resources, and the enhancement of low-impact manufacturing methods. This paper addresses some of these sustainability questions, in the context of the use of tire recycled rubber particles as aggregates of cement mortars suitable for Additive Manufacturing (AM) processes. Specifically, the effect of rubber aggregates on physical and thermal properties was investigated, to evaluate the heat-insulating performance of the compounds. The lightweight and non-polar nature of rubber improve the thermal insulation and physical-structural properties of the material, in terms of thermal conductivity, unit weight, and porosity respectively. However, these effects are closely related to the particle size and their adhesion with the cement matrix. In the second part of the manuscript, applicability study of rubber-cement compounds based on the design and finite element method (FEM)-based thermal analysis of innovative hollow bricks is presented. Fractal cavities were investigated as a functional inner architecture to improve the thermal behavior of the component. FEM results show an increase of more than 30% in thermal resistance (RT) for fractal-based brick compared to conventional designs, demonstrating that the holes’ geometric irregularity is a key feature in the thermal flow attenuation.
Automated Shape Adjustment of Interlocking Joints for Structurally Informed Design of Masonry Block Assemblages
Authors: Mousavian Elham , Casapulla Claudia
Published: March 2021

This paper introduces a tool to design structurally informed assemblages of interlocking blocks. First, the static problem of limit analysis is extended to assemblages with openings and a running bond pattern. Then, a method to measure the assemblage infeasibility due to the sliding resistance violation (namely sliding infeasibility) is described. An optimization procedure is finally presented to minimise the measured sliding infeasibility by automatically changing the shape of interlocking joints.
A Digital Logbook as an Interactive Tool to Fulfil Service Companies’ Needs and Requirements in Building Renovations
Authors: Signorini Martina , Spagnolo Sonia Lupica , Dejaco Mario Claudio
Published: March 2021

The lack of an appropriate information management along the life cycle of a construction work is one of the major issues that AEC sector is facing. The collection and exchange of information is already complex for new buildings, but it becomes even more difficult for renovations. Thus, the building logbook could have an essential role in improving the availability and quality of data for several stakeholders involved in the building process. The repository of building-related information, such as energy consumption and production or maintenance operations, is a bilateral tool to connect users and third parties. The aim of the paper is to present the digital logbook developed within BIM4EEB, an ongoing Horizon2020 project that has analysed firstly the needs and requirements necessary for its development and then it has defined its structure in order to be stored and accessed inside the BIM management system.
Effect of algae fuel addition on fuel consumption and thermal efficiency of single cylinder diesel engine
Authors: Sharudin Hazim , Rahim N.A. , Ismail N.I. , Mat Sharzali Che , Abdullah Nik Rosli , Zulkifli N.W.M. , Yusoff M.N.A.M.
Published: March 2021

The objective of this paper is to evaluate the brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE) of algae fuel blended in diesel fuel. Fuel blends of 1% of algae fuel (B1), 2% of algae fuel (B2), 3% of algae fuel (B3) and 4% of algae fuel (B4) to each 100 ml of fuel blend volume were prepared. Each algae-diesel fuel blend was tested on single-cylinder diesel engine by varying the engine loads (0, 2, 4 and 6 Nm) at a constant engine speed of 1500 rpm. Different BTE and BSFC engine performance levels were the measured parameters. Based on the result of the engine performance tests, it can be concluded that B4 blends in diesel fuel produced better BTE with 17% at 4 Nm engine load than diesel fuel. Meanwhile, the BSFC was lower for B4 with 16% compared to diesel fuel at lower engine load.
Performance Evaluation of Titanium Dioxide (TiO2) Nano Cutting Fluids in CNC Turning of Aluminium Alloy (AL319) via Minimum Quantity Lubricant (MQL) Technique
Authors: Zainal Ariffin S. , Redhwan A.A.M. , Arifuddin A. , Aminullah A.R.M. , Azim M.S. , Nughoro W. , Syafiq A.M. , Efendee A.M.
Published: March 2021

Aluminium alloy AL319 is a common alloy that has superior mechanical properties such as hardness and weldability. Nanofluids can be applied to various industrial widely in the aircraft, automotive industry and engineering problems, such as heat exchangers, cooling of electronic equipment, and chemical processes. This research objective focuses on evaluating the performance of Nano cutting fluid mixing titanium dioxide (TiO2) in CNC Turning using material AL319 Aluminium Alloy with MQL technique. The cutting performance is assessed in terms of surface roughness, cutting temperature, and tool wear was investigated. Machining parameters used for spindle speeds of 1000 to 1800 rpm and feed speeds of 0.10 to 0.20 mm / rev are used on CNC turning machines. MQL pressure is constant at 0.5 Mpa, and for parameters of TiO2 Nano liquid with concentrations of three volumes (0.5, 1.0, and 1.5%) was then compared with conventional CNC cutting liquid. Beforehand, TiO2 is diffused in CNC conventional coolant base by using the one-step method. Response surface method (RSM) via Face Centered Design (FCD) was used in designing the experimental use of the variance analysis (ANOVA) to determine which parameters are statistically important. The stability of TiO2 Nano cutting fluid is checked via visual sedimentation. The experiment concluded that the lowest cutting temperature of 28°C and surface roughness of 0.863 μm Ra when TiO2 Nano cutting fluid with 1.5% volume concentration is employed. The TiO2 Nano cutting fluids are recommended in future work to obtain more significant results. The experimental research reveals that the performance of TiO2 Nanofluid in terms of surface roughness, cutting temperature, and tool wear are found to be better compared to dry machining, wet, and MQL machining using conventional cutting fluid. Nanofluids can be considered as the future of heat transfer fluids in various heat transfer applications. They are expected to give better thermal performance than conventional fluids due to the presence of suspended nanoparticles which have high thermal conductivity.
Design optimization of passenger SUV’s crash box and bumper beam by using finite element method
Authors: Nasution Ahmad Yunus , Rejab Mohd Ruzaimi Mat , Ma Quanjin , Firmansyah Mohamad Ardy
Published: March 2021

The accident cases with front crash type occupy the largest data statistics with 7,372 cases. Theoretically, the accident cases which involve passenger cars, kinetic energy is absorbed by the complex system. Some components which are included in the system are crash box and bumper beam. The main purpose of this research is to obtain the absorption of kinetic energy when the accident happened, types of deformation, and optimization in the existing designs of crash box and bumper beam from vehicle unit. Finite element method combines with analytical value are used in the simulation. Whereas, the software used in solid modelling is SolidWork and the numerical analysis used in this research is Abaqus / Explicit. The average reaction force through simulation is obtained by averaging the results of curve plotting, while the average reaction force is obtained through formula analysis by taking material property and dimension data and then inputting it in the calculation. From the simulation, energy absorbed is 9,912 Joule from the whole original structure. The energy absorbed is less than the crash box work which is 14,066 Joule within an error value of 22 %. This is caused by the bending moment which is emerged by bumper beam. Then, optimization is done by increasing lateral lengths of bumper beam with 20 mm, 15 mm and 10 mm, therefore energy absorption increased with 20,362 Joule, 31,886 Joule and 16,348 Joule, respectively.
Methodology to calculate the required number of spare parts in order to ensure the required operability of equipment parks
Authors: Kim B G , Shakir Z N
Published: March 2021

Comprehensive mechanization of work is accompanied by large expenditures for ensuring the serviceability and operability of the machines fleet. There is an almost constant need for spare elements (machines, units, parts) to maintain the required use level of machines and equipment, as well as to perform work on schedule. An algorithm of actions allowed finding a rational level of redundancy for machines and their parts under various operating conditions and constructive improvement of technology. The article showed that the rate of failure is influenced by the natural and climatic factor, the "age" of machines, and other conditions. Optimization of the companies’ repair policy in terms of ensuring the serviceability of equipment is a complex multi-vector problem. The described methodology makes it possible to determine the necessary range and volumes of spare elements for a known fleet of machines at a given load and under the conditions of ensuring the calculated level of reliability and serviceability of the equipment, maintenance, and repair. The application of the proposed method allows optimizing the cost of spare elements while ensuring the established level of reliable operation for machines and technological sets of equipment. Also, it becomes possible to obtain rational solutions for the formation of a warehouses network on different levels to meet the needs of firms with the dispersed operation of machines and mechanisms at a large number of objects.
Imbalance in the hydrotechnical structure of seaspan lift-transition bridge in sea ferry crossing
Authors: Kligunov E S , Pozynich K P
Published: March 2021

The article is devoted to the problem of reliability of functioning of onshore structures of transport systems using the example of railway ferry crossing. A brief assessment of the role ferry crossings at the current stage of the development railway and sea transport was given. The approach to the verification calculation of lifting mechanisms, suspension elements and counterweight devices of the sea span lift-transition road-railway bridge of stage I of the Vanino-Kholmsk ferry complex in the sea port of Kholmsk for the possibility of their use due to an increase in the weight of the span structure after repair was proposed and justified.
Choosing the effective modes of compaction of hard concrete mixtures
Authors: Vasiliev V G
Published: March 2021

In the manufacture of reinforced concrete products and structures, one of the main labor-intensive operations is the compaction of concrete mixtures. All the basic physical and mechanical properties of the molded products, such as density, strength, frost resistance and others, as well as the specified shapes and high-quality surfaces, depend on the quality of mixture compaction. A decrease in the density of a product after compacting concrete mixes by 1% leads to a decrease in the strength of hardened concrete by 5-7%, and when molding products from hard mixtures – up to 13%. The effectiveness of vibration molding of concrete and reinforced concrete products is largely determined by the methods and modes of compacting concrete mixtures in molds. These questions are especially relevant when compacting hard and very hard concrete mixes. The analysis of the existing modes of molding reinforced concrete products from hard concrete mixtures is carried out in this paper. The equipment used for molding reinforced concrete products applies different types of compaction: vibration, shock-vibration and shock. The main parameters of vibroforming machinery are frequency, amplitude and acceleration of the working body, which can be symmetric and asymmetric. The advantages of using asymmetric shock-vibration modes are shown, and a method for creating shock-free asymmetric vibrations is proposed. The results of theoretical and experimental studies are presented, which have shown the high efficiency of compaction of hard concrete mixtures in shock-free asymmetric modes.
Biosynthesis of manganese oxide nanoparticles using Urginea sanguinea and their effects on cytotoxicity and antioxidant activity
Authors: Mahlangeni Nomfundo Thobeka , Moodley Roshila
Published: March 2021

Urginea sanguinea, a detoxifier utilised in African herbal medicine, contains toxic cardiac glycosides that are considered to have anticancer properties. In this study, manganese oxide nanoparticles (MnOxNPs) were synthesised using Urginea sanguinea and its isolates, a homoisoflavone (urgineanin E) and a mixture of bufadienolides (proscillaridin A, scillaren A and 5α-4,5-dihydroscillaren A), and their cytotoxic effects and antioxidant activities were investigated. The presence of absorption peaks between 262 nm and 272 nm using ultraviolet-visible spectroscopy, and Mn-O-Mn vibrations in the infrared spectrum confirmed the formation of MnO
x
NPs. Images from high-resolution transmission electron microscopy and scanning electron microscopy revealed interconnected spheroidal shapes with nanorods for MnO
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NPs (extract), and ultrathin nanosheets assembled as nanoflowers for MnO
x
NPs (urgineanin E) and MnO
x
NPs (bufadienolides). The synthesised nanoparticles were evaluated for their anticancer properties using the MTT assay. The cytotoxic effects of MnOxNPs against A549 and HepG2 cancer cell lines increased with increasing concentration with no significant cytotoxicity towards HEK293 normal cells. MnOxNPs were found to exhibit moderate free radical scavenging activity. This warrants further research into the use of manganese oxide nanoparticles synthesised with medicinal plants and active compounds as anticancer agents.
Bilinear expansion of Schur functions in Schur Q-functions: A fermionic approach
Authors: Harnad J. , Orlov A.
Published: March 2021

An identity is derived expressing Schur functions as sums over products of pairs of SchurQQ-functions, generalizing previously known special cases. This is shown to follow from their representations as vacuum expectation values (VEV’s) of products of either charged or neutral fermionic creation and annihilation operators, Wick’s theorem and a factorization identity for VEV’s of products of two mutually anticommuting sets of neutral fermionic operators.
Scrambled Cantor sets
Authors: Geschke Stefan , Grebík Jan , Miller Benjamin
Published: March 2021

We show that Li–Yorke chaos ensures the existence of a scrambled Cantor set.
Approximate tangents, harmonic measure, and domains with rectifiable boundaries
Authors: Mourgoglou Mihalis
Published: March 2021

Let

Ω
⊂

R

n
+
1

\Omega \subset \mathbb {R}^{n+1}

,

n
≥
1

n \geq 1

, be an open and connected set. Set

T

n

\mathcal {T}_n

to be the set of points

ξ
∈
∂
Ω

\xi \in \partial \Omega

so that there exists an approximate tangent

n
n

-plane for

∂
Ω

\partial \Omega

at

ξ
\xi

and

∂
Ω

\partial \Omega

satisfies the weak lower Ahlfors-David

n
n

-regularity condition at

ξ
\xi

. We first show that

T

n

\mathcal {T}_n

can be covered by a countable union of boundaries of bounded Lipschitz domains. Then, letting

∂
⋆

Ω

\partial ^\star \Omega

be a subset of

T

n

\mathcal {T}_n

where

Ω
\Omega

satisfies an appropriate thickness condition, we prove that

∂
⋆

Ω

\partial ^\star \Omega

can be covered by a countable union of boundaries of bounded Lipschitz domains contained in

Ω
\Omega

. As a corollary we obtain that if

Ω
\Omega

has locally finite perimeter,

∂
Ω

\partial \Omega

is weakly lower Ahlfors-David

n
n

-regular, and the measure-theoretic boundary coincides with the topological boundary of

Ω
\Omega

up to a set of

H

n

\mathcal {H}^n

-measure zero, then

∂
Ω

\partial \Omega

can be covered, up to a set of

H

n

\mathcal {H}^n

-measure zero, by a countable union of boundaries of bounded Lipschitz domains that are contained in

Ω
\Omega

. This implies that in such domains,

H

n

|

∂
Ω

\mathcal {H}^n|_{\partial \Omega }

is absolutely continuous with respect to harmonic measure.
On CW-complexes over groups with periodic cohomology
Authors: Nicholson John
Published: March 2021

If

G
G

has

4
4

-periodic cohomology, then finite D2 complexes over

G
G

are determined up to polarised homotopy by their Euler characteristic if and only if

G
G

has at most two one-dimensional quaternionic representations. We use this to solve Wall’s D2 problem for several infinite families of non-abelian groups and, in these cases, also show that any finite Poincaré

3
3

-complex

X
X

with

G
=

π
1

(
X
)

G=\pi _1(X)

admits a cell structure with a single

3
3

-cell. The proof involves cancellation theorems for

Z

G

\mathbb {Z} G

modules where

G
G

has periodic cohomology.
Osmosensing by WNK Kinases
Authors: Akella Radha , Humphreys John M. , Sekulski Kamil , He Haixia , Durbacz Mateusz , Chakravarthy Srinivas , Liwocha Joanna , Mohammed Zuhair J. , Brautigam Chad A. , Goldsmith Elizabeth J.
Published: March 2021

WNKs (With No Lysine [K])are soluble intracellular protein kinases that directly respond to osmotic stress through dedimerization-induced auto-phosphorylation. Assays demonstrate direct effects of osmotic pressure on autophosphorylation. SAXS (small angle x-ray scattering), SLS (static light scattering), and crystallography demonstrate a dimer to monomer transition and atomic level changes in hydration.
Exploratory polarization facilitates mating partner selection in Saccharomyces cerevisiae
Authors: Clark-Cotton Manuella R. , Henderson Nicholas T. , Pablo Michael , Ghose Debraj , Elston Timothy C. , Lew Daniel J.
Published: March 2021

Budding yeast use pheromones to select a single mating partner in crowded environments. This article shows that cells assemble mobile polarity sites that both sense and secrete pheromone, enabling a search strategy whereby encounters between the polarity sites of partner cells trigger commitment.
A Changing Landscape of Health Opportunity in the United States: Increases in the Strength of Association Between Childhood Socioeconomic Disadvantage and Adult Health Between the 1990s and the 2010s
Authors: Fuller-Rowell Thomas E , Nichols Olivia I , Jokela Markus , Kim Eric S , Yildirim Elif Dede , Ryff Carol D
Published: March 2021

Understanding the changing health consequences of childhood socioeconomic disadvantage (SED) is highly relevant to policy debates on inequality and national and state goals to improve population health. However, changes in the strength of association between childhood SED and adult health over historic time are largely unexamined in the United States. The present study begins to address this knowledge gap. Data were from 2 national samples of adults collected in 1995 (n = 7,108) and 2012 (n = 3,577) as part of the Midlife in the United States study. Three measures of childhood SED (parents’ occupational prestige, childhood poverty exposure, and parents’ education) were combined into an aggregate index and examined separately. The association between childhood SED (aggregate index) and 5 health outcomes (body mass index, waist circumference, chronic conditions, functional limitations, and self-rated health) was stronger in the 2012 sample than the 1995 sample, with the magnitude of associations being approximately twice as large in the more recent sample. Results persisted after adjusting for age, sex, race, marital status, and number of children, and were similar across all 3 measures of childhood SED. The findings suggest that the socioeconomic circumstances of childhood might have become a stronger predictor of adult health in recent decades.
Comprehensive review and evaluation of computational methods for identifying FLT3-internal tandem duplication in acute myeloid leukaemia
Authors: Yuan Danyang , He Xiaoyu , Han Xinyin , Yang Chunyan , Liu Fei , Zhang Shuying , Luan Haijing , Li Ruilin , He Jiayin , Duan Xiaohong , Wang Dongliang , Zhou Qiming , Gao Sujun , Niu Beifang
Published: March 2021

Internal tandem duplication (ITD) of FMS-like tyrosine kinase 3 (FLT3-ITD) constitutes an independent indicator of poor prognosis in acute myeloid leukaemia (AML). AML with FLT3-ITD usually presents with poor treatment outcomes, high recurrence rate and short overall survival. Currently, polymerase chain reaction and capillary electrophoresis are widely adopted for the clinical detection of FLT3-ITD, whereas the length and mutation frequency of ITD are evaluated using fragment analysis. With the development of sequencing technology and the high incidence of FLT3-ITD mutations, a multitude of bioinformatics tools and pipelines have been developed to detect FLT3-ITD using next-generation sequencing data. However, systematic comparison and evaluation of the methods or software have not been performed. In this study, we provided a comprehensive review of the principles, functionality and limitations of the existing methods for detecting FLT3-ITD. We further compared the qualitative and quantitative detection capabilities of six representative tools using simulated and biological data. Our results will provide practical guidance for researchers and clinicians to select the appropriate FLT3-ITD detection tools and highlight the direction of future developments in this field. Availability: A Docker image with several programs pre-installed is available at https://github.com/niu-lab/docker-flt3-itd to facilitate the application of FLT3-ITD detection tools.