bluuebunny/crossref_metadata_2025 huggingface dataset:
Microcomputer Energy Saving Control System for Electric Vehicles Under Artificial Intelligence
Authors: Nie Yongtao , Dong Cui
Published: May 2021

Faced with the problem of dwindling oil resources and increasingly strict automobile exhaust emission standards, the advantages of pure electric vehicles in energy saving and emission reduction have become more and more prominent compared with traditional fuel vehicles. However, in view of the current development scale of the pure electric vehicle market, there are still many deficiencies in the aspects of power density, cycle service life and replacement cost. This paper mainly studies the microcomputer energy saving control system of electric vehicle under the background of artificial intelligence. In this paper, the STM32F103 series chip is used as the main control chip of the battery energy management system. Then according to the requirements of the subject of each module circuit design, forming a complete battery energy management system circuit design. In this paper, the designed electric vehicle energy management system has been tested. The test results show that the electric vehicle battery energy management system has perfect function, sTable operation, and can realize the energy management of electric vehicle battery pack. It can accurately predict the state of charge of electric vehicle lithium battery, and effectively improve the battery performance of electric vehicle lithium battery, and achieve the effect of energy saving.
Cooperative Operation Mechanism of Multi-Energy Microgrids Based on Nash Bargaining Method
Authors: Shuai Xuanyue , Wang Xiuli , Guo Hui , Ma Zhicheng
Published: May 2021

With the increasing openness of the electricity sales side of the electricity market, different stakeholders can improve economic benefits through cooperative operation. Aiming at a type of multi-energy microgrid with electricity-heat coupling, this paper proposes a multi-microgrid operating mechanism based on cooperative game. Taking the operating cost of each microgrid’s transaction with the distribution network as the breaking point of the negotiation, the Nash bargaining method is used to solve the electric energy transaction volume and revenue transfer between each microgrid, so that the operating cost of each microgrid reaches the Pareto optimal. The total operating cost of all microgrids is minimized. Taking into account the non-convexity of Nash bargaining solution, the bargaining equilibrium problem is converted into two sub-problems and solved with the Yalmip-Ipopt tool. Finally, we proves the effectiveness of the method proposed in this paper by simulation, and provides a reference scheme for the cooperative operation mechanism of multiple microgrids.
East Transbaikal zeolite production: Potential and integrated Ecological safety
Authors: Razmakhnin KK
Published: May 2021

The author discusses resource potential of zeolite-bearing rocks in East Transbaikal with regard to geoecological safety of mining and processing. The role of climate in the environmental impact of zeolite production is identified. Potential activities aimed to reduce anthropogenic load on the environment are proposed.
Experimental investigation of shock pulses in the piston–bit system in interaction with rock mass
Authors: Efimov VP , Gorodilov LV
Published: May 2021

The paper presents a measurement procedure for accelerations generated in the piston–bit system in interaction with rock mass. The acceleration oscillograms are analyzed. The quantitative estimates of shock pulses are discussed with regard to their influence on fracture performance.
Stress–strain analysis of crack-weakened piecewise uniform rock blocks
Authors: Krasnovskii AA
Published: May 2021

The author undertakes the stress–strain analysis of a crack-weakened piecewise homogenous rock block. The relations for estimating stresses and displacements at the whole boundary of the rock block, at the edges of the crack, at the line of continuation of the crack and at the interfaces between the layers of rocks with different properties inside the block are presented. The numerical algorithm is constructed. The research findings prove the complex structure of the stress–strain state and the dependence of the solution on many input parameters.
Limit load in the problem on penetration of wedge-shaped tool in anisotropic medium
Authors: Chanyshev AI , Abdulin IM
Published: May 2021

The mathematical model of plastic deformation in an initially anisotropic medium assumes that principal directions of strain in elasticity remain principal directions of strain in plasticity and fracture as well. The modeling considers penetration of a bit represented by a cylindrical tool with a wedge-shaped tip. The maximal penetration depth of the bit is calculated at the preset initial rate of penetration. The influence of the anisotropy of the medium and the bit parameters on the bit penetration depth is studied.
Efficiency of modified concrete in lining in underground structures
Authors: Arystan ID , Nemova NA , Baizbaev MB , Mataev AK
Published: May 2021

The authors discus an efficient concrete technology toward highest advance rates in tunneling in unstable rocks at minimized labor input.
New Materials Based on Polytetrafluoroethylene and Modified Filling Materials in Mining Industry
Authors: Isakova TA , Petrova PN
Published: May 2021

Investigation into properties of polymer composite materials based on polytetrafluoroethylene and natural zeolites modified with F-42 and F-2M fluoroplastics is proposed in the present paper. It is shown that different zeolite modification techniques govern performance of composites. In the mechanical activation process a small amount of F-2M bearing filler improves Young’s modulus and relative tensile elongation of composites under rupture by 20-50%. Introduction of F-2M modified filler in amount of 5% by weight provides 380-fold increase in durability as compared to polytetrafluoroethylene. F-42 fluoroplastic used as a modifier of zeolite enables to gain 2-2.75-fold lower plastic yield of composites. The present research findings make it possible to consider the composites as promising materials in the mining industry.
Selection of turbulence model in ventilation modeling for blind stopes
Authors: Kolesov EV , Nakaryakov EV
Published: May 2021

The authors present the results of mathematical modeling of working area ventilation in a blond stope using the methods of computational aerodynamic and different turbulence models. The analytical model is verified by comparing the model and in situ data.
Mechanochemical brown coal destructuring to produce humic species
Authors: Moskalenko TV , Mikheev VA , Vorsina EV
Published: May 2021

The research data on the mechanical destruction of brown coal in the presence of an oxidizing agent are reported in the present paper. The study object is brown coal specimens with high (more than 30%) and low (less than 10%) initial contents of humic acids. The mechanochemical oxidation efficiency was evaluated by a change in the inorganic component content and in the yield of humic acids as the organic component in the ash composition. Hydrochloric acid solutions of 1-5% concentration were used as an oxidizing agent. Oxidation was considered and carried out as a raw material pretreatment with its subsequent processing to produce humic species, mechanical activation was introduced into the flowsheet for brown coal processing in view to foster interaction between solid particles and the reagent. The data obtained indicate the effectiveness of this process in terms of both increasing the yield of humic acids, and reducing the ash content in the prepared coal.
Improvement of a hot water producing system in a chili sauce
Authors: Phayom Warachit , Bamrungcharoen Jakkaphan
Published: May 2021

In Udon Thani Province (Thailand), Mahachai Food is a small-sized food processor that manufactures and distributes chili sauce to the local market. The manufacturer is faced with various problems in its production facility. A significant problem was in its hot water system. The system required workers to transfer hot water by buckets. Also, its energy costs were quite high. Thus, this research aims to upgrade the manufacturer’s hot water production system. In doing so, the investigator designed vessels and LPG stoves that preheated the water by solar flat plate collectors and implemented a water transfer system using a pipe system. The results are as follows: 1) Water transfer required only one-third of the original time. This reduced the need for workers from four persons to just one. It also helped increase safety in the workplace since the potential of human exposure to hot water was greatly reduced. 2) The efficiency of the hot water producing system was increased. 3) The cost of energy-producing hot water was reduced.
Thermal performance of heat pump dryer using R32 as refrigerant.
Authors: Ponwapee P. , Somsila P. , Teeboonma U. , Namkhat A. , Pumchumpol S.
Published: May 2021

The objective of this research was to study the performance of heat pump dryer using refrigerant R32 and ginger was selected as testing material. The experiments were conducted under conditions; drying temperature of 45, 50, and 55 °C and air velocity of 1.0, 1.5 and 2.0 ms-1. Drying rate, the specific moisture extraction rate, the specific energy consumption, and the coefficient of performance of heat pump were tested. The results revealed that the increment of drying temperature or air velocity resulted in increment of drying rate, power of heat pump dryer, and specific moisture extraction rate whilst specific energy consumption decreased. Additionally, it was revealed that drying temperature or air velocity did not affect the coefficient of performance of the heat pump.
Analyzing esterification kinetics of model bio-oil with ethanol catalyzed by a green catalyst
Authors: Prasertpong Prapaporn , Tippayawong Nakorn
Published: May 2021

Fast pyrolysis of biomass is a potential method for the production of bio-oils as a renewable liquid fuel. Bio-oils contain a large number of organic compounds, particularly carboxylic acids, which cause corrosiveness and instability that are troublesome for storage and for the transportation of fuel. Upgrading is an important process to transform bio-oils into high-quality biofuels. Contained organic acids are treated with alcohol to convert them into esters by esterification which may be considered as a good intermediate bio-oil upgrading method. This work presents a kinetic study for 12-tungstosilicic acid (a type of heteropoly acid, HPA) catalyzed esterification of a model bio-oil with ethanol. The main compound of the agro-residue-derived bio-oil was illustrated by oleic acid. The kinetic study was investigated under the molar ratio between ethanol to oleic acid of 9.11:1 and catalyst loading of 10 wt% condition with the varied reaction temperature in the range of 35-75°C. The result showed that a pseudo-first-order was suitable to represent the kinetic model for esterification of the model bio-oil. By fitting between the experimental results and kinetic model, the activation energy (Ea) and the pre-exponential factor (A) were found to be 31.5 kJ/mol and 432 min−1, respectively. This comparatively low activation energy equated to other catalytic esterification proved that the HPA catalyst (12-tungstosilicic acid) considered here was an assured green catalyst for esterification in the bio-oil upgrading process.
Design and fabrication of a solar-dish concentrator with 2-axis solar tracking system
Authors: Savangvong Pongnarin , Silpsakoolsook Banterng , Kwankoameng Sutapat
Published: May 2021

This paper presents an economical parabolic solar collector including design analysis, fabrication, and testing of the solar concentrator with a dual-axis solar tracking system. The design goals of the solar dish are high concentrating temperature and power density but low weight and cost. To achieve a high-efficiency dish, minimizing loss is important therefore the design focuses on high reflectability, low heat absorption with an optimum dish profile. The dish is a parabolic shape with two layers of different materials. Three reflector materials, an emergency blanket, PET-Mirror, and Mirror are introduced on the top layer as the solar reflectance. The second layer, fiberglass that is lightweight, easy to shape up in various features, and cheap, is used as a dish structure. The dish is installed with a 2-axis solar tracking system and supported by a steel column. The ¼ inch copper tube is coiled as a receiver. The receiver is placed at the focal point of the solar dish. To evaluate the heat at the focal point, water is pumped through the receiver coil to absorb the heat from the focal point. The heat output of the solar dish is calculated from the temperature difference of the water inlet and outlet of the receiver coil. The temperature at the focal point was presented along with the heat power output, and solar dish efficiency.
A comparative study of equivalent circuit models for a Li-ion battery pack of an electric Tuk-Tuk
Authors: Rajchapanupat Natcha , Poramapojana Poowanart
Published: May 2021

This paper presents developments and validations of Lithium Nickel Manganese Cobalt Oxide (NMC) battery cell and battery pack models. A 7.4 kWh NMC battery pack is installed on an electric Tuk-Tuk equipped with a 3 kW motor. The battery pack is configured of four cells connected in parallel and 20 sets of the four cells connected in series. Based on the first-order and the second-order equivalent circuit models, battery cell and battery pack models are developed in Matlab/Simulink environment. For parameter identifications of the cell model, pulse discharge tests are performed at room temperature with 10% State of Charge (SOC) interval. The lumped heat capacitance method is applied to the battery models. The battery cell model is validated with SOC, cell center temperatures and terminal voltage using the experimental data of constant current discharge tests. With the battery pack configuration, the battery cell model is scaled up to match the battery pack voltage and its capacity. The dynamics of the battery pack models are validated with the vehicle testing data using the no-load, wide-open throttle and real road tests. The simulation results show good agreement with the test data. Using the developed battery models, vehicle performance and its energy consumption can be improved by optimizing battery cell and pack configurations.
A fuzzy controller for two energy storage management system in electric bicycle
Authors: Pera P. , Masomtob M. , Intano W. , Kaewpradap A.
Published: May 2021

This paper presents an energy management system for an electric bicycle that runs in local community in Thailand. Fuzzy logic technique is applied in this system to control supercapacitor and battery management according to the demand of load power. The load of the electric bicycle depends on speed of each driving cycle. Mamdani-based fuzzy logic controller is selected to control the ratio of output between supercapacitor and lead acid battery. Fuzzy logic controller aims to reduce battery usage during peak current occured from the electric bicycle and passes speed bump in order to extend the lead acid battery life time.
Fuzzy-based potential field collision avoidance technique for unmanned surface vehicles
Authors: Tanakitkorn Kantapon
Published: May 2021

Collision avoidance is a crucial part of the autonomous operation of an unmanned surface vehicle (USV), especially in a dynamic environment. This work presents a fuzzy-based potential field algorithm for collision prevention when a USV encounters an obstacle, either moving or static. Two types of repulsive potential functions are employed. The Gaussian repulsive potential is applied to repel the own ship (OS) away from the target ship (TS). On the other hand, the vortex potential function is used to smoothly deviate the heading of the OS towards the side that quickly resolves the collision. The fuzzy membership functions and rules are imposed to classify the encounter condition and apply the appropriate potential functions accordingly. Head-on and crossing encounter scenarios are simulated to demonstrate the performance of the proposed algorithm. The simulation results have shown that, when the collision is detected, the algorithm is effective in generating the vector field that directs the OS away from the collision path. Once the collision is resolved, the algorithm lets the OS continue the original course.
Parametric study of composite wing box for high altitude platform using finite element analysis
Authors: Thaiprayoon Nontawat , Chalernphon Kittigorn , Somtua Chompunut , Aroonjarattham Panya
Published: May 2021

This paper aims to evaluate the degree and the number of pile stack between five and six ribs wing box that created from the Eppler 397 Airfoil (e397-il) model. The model was varied three numbers of pile stack and six degrees of angle of pile stack to find the best result for the composite material to construct the High-Altitude Platform (HAP). The thickness of pile was fixed at 0.234 mm. The structure of wing box has the safety of factor 5.7 and receive load 3,052 N. The model was analysed by ABAQUS software to compute the vertical-static such as Tsai-Hill and skin defection that did not exceed 1 for Tsai-hill and 2 mm for skin defection. The results were shown that the wing box had six ribs model with the angle of pile stack as [+45/-45/90/90/0/90/90/-45/+45] was the best model in this research. It had Tsai-Hill 0.030 and skin defection 0.348 mm. The model had more ribs and number of pile stack increase the strength of wing box and the degree of pile stack between the outer and the adjacent layer should be a perpendicular direction.
Study of 3D printing for forming spoke of non-pneumatic tire using finite element method
Authors: Suvanjumrat Chakrit , Rugsaj Ravivat
Published: May 2021

Over the last decade, non-pneumatic tire (NPT) was developed by replacing air in traditional pneumatic tire with polyurethane (PU) spoke. However, there are some limitations in building complex shape of spokes. Recently, the 3D printing technique has been used to form complex part of real products. Consequently, it can use to build the complex spoke of NPT. This research aimed to study the possibility of using 3D printing technique to build the complex shape of spoke for NPT. This can be done by studying the mechanical properties of 3D printing material suitable for NPT’s spoke. The PU filament was printed into tensile specimens to carry out the stress-strain relationship by using universal testing machine. The finite element (FE) model of NPT was then created using mechanical parameters of the tension result. The vertical stiffness testing on the NPT model was analyzed. The NPT performance to support the vertical load of real NPT and FE model with original material was carried out to compare with the 3D printing model. Furthermore, the advantage and disadvantage including limitation of using 3D printing technique to manufacture the NPT spoke were discussed.
Effect of Al2O3 nanoparticle additives on the performance characteristics of rough journal bearings
Authors: Gunnuang Waleephan , Aiumbhornsin Chatchai , Wongsa-Ngam Jittraporn , Mongkolwongrojn Mongkol
Published: May 2021

This paper investigates the influence of Al2O3 nanoparticle additives on static and dynamic characteristics of water-lubricated rough journal bearings under thermo-hydrodynamic lubrication (THL). The time-dependent modified Reynolds equation and the approximated adiabatic energy equation have been formulated and solved numerically with boundary conditions and initial conditions. The results are presented for dimensionless maximum film pressure, dimensionless maximum film temperature, dimensionless minimum film thickness, eccentricity ratio, attitude angle, dimensionless friction force, spring constants, damping coefficients and mass parameters for both journal bearings with transverse roughness patterns and with longitudinal roughness patterns under a dimensionless load of 7. The results show that journal bearings with Al2O3 nanoparticle additives tend to significantly increase load carrying capacity and minimum film thickness by decreasing both the eccentricity ratio and temperature rise for longitudinal roughness patterns. For journal bearings with longitudinal roughness patterns and lubricated with Al2O3 nanoparticle additives, the stability region tends to increase.
Comparison of two different surface for rolling airless tire by finite element method
Authors: Suvanjumrat Chakrit , Rugsaj Ravivat , Phromjan Juthanee
Published: May 2021

Drum testing was carried out to determine rolling tire performance. The finite element method was used to model the drum testing instead. In order to yield accurate results, the generalized Maxwell’s viscoelastic material model with hyperelastic material model was employed to simulate the drum testing on the airless tire. However, it consumed a lot of simulation time because of the contact surface between tire and drum was difficult to compute by using a finite element method. The finite element model of rolling an airless tire on a flat surface was developed. The contact patch and spoke deformation were carried out to investigate the surface effects. The spoke deformation of rolling an airless tire on a flat surface was found to be in accord with the curvature surface of the drum. The flat surface showed little difference in the contact area against the drum. Particularly, it was found that the analysis time of rolling an airless tire on a flat surface was less than the drum 10.13 times.
Development of a herbal cream mixer with a homogenizer-stirrer and circulating water cooling system
Authors: Suttibak Suntorn , Deesapa Kamonrat , Saengmanee Chayarnon , Chuntanapum Athika
Published: May 2021

This paper presents a study on the development of a herbal cream mixer with a homogenizer-stirrer and circulating water cooling system. The machine is designed to address problems in the production of herbal creams and lotions by the entrepreneurs of the Thangrak Company Limited, Chiang Yuen Sub district, Muang District, Udon Thani, Thailand. It has a capacity of around 100 liters and employs a circulating water-cooling system. The homogenizer uses a 3-horsepower electric motor to control the rotation speed of the stirring head, which in turn controls the mixer speed. The level of the machine is adjusted using an electric hoist. Cream was produced in 80 liter batches. Mixer speed was tested at four levels: 30 Hz (1,800 rpm), 35 Hz (2,100 rpm), 40 Hz (2,400 rpm) and 45 Hz (2,700 rpm). The total time of each run was approximately 30 minutes. The results showed that a temperature reduction of the ingredients from an initial temperature of around 70°C down to approximately 33°C. The process took around 1 hour and 30 minutes. From the experimental results, it was found that the product made at 1,800 rpm had a lower viscosity of around 78.4 Pa.s. The cream of this batch was not as homogenized as it should have been. However, tests at 2,100, 2,400, and 2,700 rpm produced a creamy material with increased viscosities of 94.3, 94.8 and 96.7 Pa.s, respectively. The herbal cream products made in the developed mixer with homogenizer-stirrer and a circulating water-cooling system were homogenous. They compared favorably with herbal cream products sold in the market. The designed mixer produced a cream product that is more homogenous, while the products now available on the market have separated cream and are not as well homogenized.
Numerical study on bending response of auxetic 2D-lattice plates
Authors: Suttakul Pana , Fongsamootr Thongchai
Published: May 2021

In this study, the bending response of 2D-lattice plates having auxetic unit cells is determined by using the homogenization method based on equivalent strain energy. The auxetic unit cells in this study are different topologies of re-entrant hexagonal unit cells. In the homogenization method, the effective out-of-plane elastic properties of an auxetic 2D-lattice plate are obtained from the strain energy values of its unit cell under different curvature modes, determined by the finite element method. In the analysis, the auxetic unit cells are considered as frames whose struts are modeled as Euler beams. The effective elastic properties, i.e., the effective bending moduli, Poisson’s ratios, and shear modulus, are described as the bending response of a 2D-lattice plate subjected to out-of-plane bending. In the validation, the effective elastic properties of some auxetic 2D-lattice plates obtained from their unit cells by the homogenization method are numerically compared with those obtained from direct structural analysis of the plates. Besides, the obtained results show how the bending response of the auxetic 2D-lattice plates can be adjusted by varying their unit-cell geometries, especially the internal cell angle.
Effect of carbon content on microstructure and mechanical properties of sintered Fe-Mo-Mn-C alloys
Authors: Wanalerkngam A. , Boonmee S. , Krataitong R. , Morakotjinda M. , Pongsak W. , Tosangthum N. , Tongsri R.
Published: May 2021

Sintered Fe-Mo-Mn-C alloys were produced by sintering of mixtures of pre-alloyed Fe-0.5Mo-0.15Mn powder and varied carbon amounts (0.30-1.20 wt.% with 0.15% increments) followed by slow cooling in furnace. Microstructures and mechanical properties of the sintered alloys varied with added carbon content. With up to 0.75 wt.% carbon additions, the sintered alloys exhibited polygonal ferrite plus non-cooperative eutectoid decomposition products. With 0.90 wt.% carbon addition, the whole microstructure of the sintered alloy mainly consisted of non-cooperative eutectoid decomposition products. With 1.05 and 1.20 wt.% carbon additions, the microstructures of the sintered alloys consisted of large grain boundary carbides and mixed non-cooperative and cooperative eutectoid decomposition products within grains. Tensile strength showed the maximum value in the sintered alloy with 1.05 wt.% carbon addition. Elongation values decreased sharply with increasing carbon contents of up to 0.60 wt.%, beyond which the values were constant.
FEM model of protection bullet helmet made from composite material.
Authors: Promma R. , Phongphinittana E. , Nimdum P.
Published: May 2021

Damage evolution, mechanical behaviour, energy absorbtion, back-face deformation (BFD) and the perforation performance of Kevlar epoxy woven composite with and without foam (PU foam) were examined for various impact energies based on the drop weight test. The Kevlar woven composite induces different damage and deformation depending on its hybrid patterns. The Kevlar composite with PU foam decreases significantly, and the BFD of shell composite and transform locally deformation become a global nature. In addition, damage type - as fibres break - is primary dominant for Kevlar composite without PU foam. However, the role major damage as delamination, significantly appear for Kevlar composite with PU foam. In order to investigate the damage mechanism, energy absorbtion and BFD, FEM simulation were also performed. The FEM simulation is in very good agreement with the drop weight test. Finally, the FEM study showed that PU foam is able to decrease significantly, the BFD of composite shell, and the contact force on the skull, during ballistic impact.
The study on the characterization of sintered hot forging and austenite stainless steels
Authors: Eiumtadanai Sittipong , Mahathanabodee Sithipong , Tongsri Ruangdaj , Vetayanugul Bhanu , Sumate  , Poomiapiradee
Published: May 2021

The powder metallurgical (PM) process, consisting of compaction and sintering, is commonly used to produce sintered structural parts applied in various industrial fields. Sintered parts always have porosity due to limited materials transport by solid-state diffusion from powder particles to voids between them. Sintered specimens with low porosity show superior mechanical properties. Hot forging is one of processes for enhancing density of sintered parts. This process was applied to sintered austenitic stainless steels ( 303L, 304L, 310L and 316L). The hot-forged specimens showed increased density. This led to remarkable increase of hardness (up to 5 times). Due to the hot working nature of the process, microscopic changes in the hot-forged specimens during the process were examined. It was found that grain size and volume fraction of twins were significantly deceased.
Sintered Fe-Mo-Mn-Si-C alloys
Authors: Nakornkaew P. , Patcharawit T. , Wila P. , Morakotjinda M. , Yotkaew T. , Tosangthum N. , Tongsri R.
Published: May 2021

Sintered Fe-Mo-Mn-Si-C alloys were produced by alloying silicon and carbon elements to pre-alloyed Fe-0.5Mo-0.15Mn powder via sintering of mixtures of pre-alloyed powder and varied silicon carbide amounts (0.5-4.0 wt.% with 0.5 increment). The sintered alloys were cooled in a sintering furnace. Microstructures and mechanical properties of the sintered alloys were altered depending on added silicon carbide content. With up to 2.0 wt.% silicon carbide additions, the sintered alloys exhibited polygonal ferrite plus eutectoid decomposition products, showing non-cooperative ferrite and carbide growth mode. With silicon carbide contents of ≥ 2.5 wt.%, the sintered alloys exhibited microstructural feature similar to that of a ductile iron, i.e., a common feature consisted of a black particle enveloped with ferrite and pearlite. Tensile strengths of the sintered alloys increased but elongation values decreased with increasing added silicon carbide content. The sintered alloys produced by 3.5 and 4.0 wt.% silicon carbide showed high strengths and considerably good elongation values.
Sintered Fe-Ni-Si-C alloys
Authors: Kaewkam Tiwat , Kansuwan Panya , Ohtake Naoto , Wila Pongsak , Krataithong Rungtip , Tosangthum Nattaya , Yotkaew Thanyaporn , Tongsri Ruangdaj
Published: May 2021

The aim of this research is to explore the effect of nickel content on microstructural development and mechanical properties of sintered Fe-Ni-Si-C alloys. The sintered alloys were prepared from powder mixtures of pre-alloyed Fe-Ni-based powders (nickel contents varied as 0.45, 0.90, 1.80, and 4.00 wt.%) and fixed 4 wt.% silicon carbide powder by using a powder metallurgical process. Sintering was performed in a vacuum furnace at 1250°C for 45 minutes and slow cooling in the furnace. Microstructures of sintered alloys varied with nickel contents. Nickel showed a strong influence on promoting bainitic ferrite/martensite-austenite (BF/M-A) structure formation. Retained austenite in BF/M-A structure was found to increase with increasing nickel content. Tensile properties (strength and elongation value) of sintered alloys increased with increasing nickel content.
Phase transformation and mechanical properties of sintered Fe-Mo-Si-C-(Cu) alloys
Authors: Morakotjinda Monnapas , Ruangchai Kittikhun , Vetayanugul Bhanu , Krataitong Rungtip , Tosangthum Nattaya , Wiengmoon Amporn , Tongsri Ruangdaj
Published: May 2021

Sintered Fe-Mo-Si-C alloys, prepared from pre-alloyed Fe-0.85Mo powder, fixed 4wt. % silicon carbide powder and varied graphite powder contents, showed microstructures similar to those of ductile cast irons, i.e., the microstructural feature consisted of a black particle enveloped with matrix consisting of ferrite halo and pearlite. The varied added-graphite content caused morphological change from black nodular to black vermicular particles. With increasing added-graphite content resulted in the decrease of black nodular/vermicular particle fraction, the increase of pearlite fraction and the slight change of ferrite fraction. The black nodular particles were either graphite or Fe-Mo-Si-C/graphite core-shell particles whereas black vermicular particles were totally composed of carbon. With 2 wt.% copper addition, the morphologies of black nodular and vermicular particles in sintered Fe-Mo-Si-C-Cu alloys were not affected, but one component of the matrix changed from pearlite to duplex structure consisting of bainitic ferrite (BF) and martensite-austenite (M-A) constituent. The change of matrix component from pearlite to duplex BF/M-A structure led to drops of ultimate tensile strengths and elongation values but small effects on yield strengths and hardness values. No benefits of tensile properties were gained from the duplex structure due to coarse BF/M-A size.
Evaluation of conventional invasive measurements and examination of non-invasive measurement technique on human body core temperature
Authors: Yoshida Atsumasa , Kamon Rinzo , Naka Takuma , Chigusa Narihisa , Kinoshita Shinichi , Kawabata Takashi
Published: May 2021

It is important in many cases to measure and monitor, human body core temperatures, to prevent the likes of heat stroke and hypothermia. Measuring core body temperatures is also important for example, in relation to the basal body temperatures of women, and for improving the quality of life for vulnerable people such as infants, and those with cervical spine injuries. In doing so, thermal environmental changes can be monitored. However, todays conventional measuring method is apparently invasive because a temperature sensor has to be inserted into the body, from the outside. Characteristics of the body parts measured were considered by the subject experiments. There was a difference in core temperatures, depending on the measurement body parts, and it was found that the temperature decreased in the order of rectum, sublingual, and tympanic during normal times. It was confirmed that the tympanic temperature showed the most significant increase in core temperature, with running and the sublingual temperature the best in responsiveness. As a non-invasive core temperature measurement method, the basic characteristics were examined by the heat transfer experiment for the dual-heat-flux method. Thus, it was clarified that adequate temperature accuracy can be guaranteed if appropriate materials, thicknesses, and sizes are selected and the adiabatic condition for the peripheral part is fulfilled.
Numerical simulation of tooth extraction socket: alveolar bone regeneration
Authors: Furukawa Rintaro , Nagayama Katsuya , Matsuo Masato
Published: May 2021

Recently, regenerative medicine has received attention owing to the progress of an aging society. Regenerative dentistry, such as bone regenerative therapy and implant treatment to regain bone loss as a result of active periodontal disease, is actively performed. The alveolar bone is a functional bone that supports teeth and buffers occlusal pressure. In the implant treatment, the implant is inserted into the tooth after it has been extracted. After the implant is inserted, the alveolar bone will regenerate over about three months and the implant will be fixed in place. During this process of alveolar bone regeneration, there have been problems with the implant and alveolar bone not bonding. This work was contributed to dental regenerative medicine by building a simulation model of alveolar bone regeneration. After tooth extraction is performed, the alveolar bone regenerates by chemically converting calcium (Ca) secreted from the newly formed blood vessels into hydroxyapatite, which is the main component of bone. Thus, its internal structure and external shape are mechanically affected around the bone. The main purpose of this study is to establish a mathematical model, introduced as the Ca transport model that is secreted from the newly formed blood vessels, and mechanical factor model expressed as bone remodeling for analyzing and predicting the interaction of angiogenesis and bone regeneration. As a result, we were able to obtain a good agreement between the qualitative features of the experimental images and the simulation results.
Numerical simulation of skin formation: epidermal stem cells and undulation of the basal layer
Authors: Oba Shu , Nagayama Katsuya
Published: May 2021

The basal layer at the base of the epidermis produces new epidermal cells once a week and plays an important role in skin formation. Interestingly, the basal layer undulates, and the amplitude of this undulation is dependent on age or disease. However, the mechanisms driving this phenomenon have not been well studied. This work simulated the skin formation process using an original method to understand the mechanism of the undulation formation in the basal layer. The basal layer has cells with both short and long cell cycles, but only the former has been examined in previous studies. Accordingly, we more accurately simulated the skin formation process by including cells with a long cell cycle and observed undulation of the basal layer. Based on our findings, we propose that the basal layer undulates due to the interaction between two types of basal layer cells.
Experimental investigation on durian thorns
Authors: Phungsara Bundit , Phongphinittana Ekkarin , Jearanaisilawong Petch
Published: May 2021

Durian is a fruit that has a round shape with thorny shell. When a durian is ripe and falling down from a tall branch to the ground, its thorn help absorb shock from an impact with the ground and lessen the damage to its soft internal flesh. This research aims to investigate the structure of durian thorn and its mechanical properties. Among varieties of durian cultivars, Monthong durian is selected as a representative variety because of its popularity and availability. Thorns and components of durian peels are harvested from a ripened durian and stored in vacuum refrigerated bags. Modulus of Elasticity of each component is measured by performing uniaxial tensile tests on coupon samples. The results show the gradients of modulus of elasticity at various points on the durian peels. The experimental results can be used as inputs for finite element simulations of durian thorns for further analysis.
Design of opener shape for improving gimbal tongue shift on y-axis
Authors: Klayaubol Warut , Pimsarn Monsak
Published: May 2021

There are four necessary components for testing read-write efficiency of Slider, which are [1] Slider electrical testing machine [2] Fixture, a tool for holding Slider while testing [3] Slider to read and write data in hard disk drive and [4] Opener, a mechanism to open a fixture for loading and unloading Slider. The opener should open a fixture only in x direction but it appears that the opener drives a fixture in both x and y directions which results in misalignment of Slider in a fixture. A poor Slider alignment definitely affects a read-write efficiency of Slider. Therefore, this article will show a study of opener shape that relates to fixture behaviour and also a comparison of four designs of opener-arm angle (15 degrees, -15 degrees, -30 degrees and -40 degrees) by using Finite Element Analysis (FEA). Result shows -40 degrees opener is the best one that can open the fixture only in y direction and meets the design requirement.
Computational study of the flow field characteristics of the radial-swirl burners for a small gas turbine
Authors: Soontornpasatch Tosaporn
Published: May 2021

The aim of this study is to investigate the flow field characteristics of the radial-swirl burner which is developed for a small gas turbine. To create a stable flame during the combustion process, the burner has to create a reversal flow area or a recirculation flow. Without this zone, the combustion process cannot be created. Therefore, the characteristics of the flow field in the burner is very critical. The current study applied two types of the radial-swirl burner. One has a straight-type vane and the other has a nozzle-type vane. The flow angle of both types are varied from 40°, 50° and 60°. The mass flow rate of air is varied from 1.0 to 1.8 kg/min. The commercial computational fluid dynamic program, ANSYS FLUENT is also used. The results of the simulation are discussed in this paper.
Effect of audio pre-processing technique for neural network on lung sound classification
Authors: Chaiyot Krittaya , Plermkamon Supattra , Radpukdee Thana
Published: May 2021

In this paper, we intended to study the effect of two audio pre-processing methods to multilayer feedforward network performance on lung sound classification problem. The first one is Mel Frequency Cepstral Coefficients (MFCC) and the second is the MFCC supplement with Linear Discriminant Analysis (LDA). Datasets applied in this study came from Kaggle Respiratory Sound Database, which is the largest resource for machine learning. As a result, MFCC supplement with LDA has both good performance and significant improvement than conventional MFCC.
Structural analysis of three-dimensional finite element model to design multifunction wheelchair for patients
Authors: Keangin P. , Chawengwanicha P. , Wimala N. , Nakbanpotkul T.
Published: May 2021

The disabled and patients, especially hemiplegia and paraplegia cases and elder need to use a wheelchair for movement and admitted to the hospital or stay at home. The problem of using wheelchairs for patients and the elder is due to their different shapes. There is only a standard type of wheelchair in a hospital, therefore could not respond to differences in shape and usability. The ability of a wheelchair that does not provide enough facilities will result in the service as being ineffective in achieving and will make patients feel uncomfortable. The basis of the strength analysis, as well as stress distribution of the device structure design, is still minimal due to computer program limitations. A comprehensive understanding of the fundamentals of strength analysis will support the recommendation to design of wheelchair to handle patient for appropriate use in each situation. This research aim provides strength analysis to design the multifunction wheelchair. The multifunction wheelchair is designed to be turned into a bed, height-adjustable to use in a situation where a standard wheelchair could not be achieved due to the height is not enough and arm rest’s width adjustable for the convenience of patients with different body shapes. The detail regarding concept design and strength analysis of main components are solved by the finite element method (FEM) with a three-dimensional model. The results obtained from the simulation solution are examined and compared with the analytical solution. It is found that the highest maximum stress value does not exceed the yield strength of the material. The obtained results can be helpful in determining the basis for the guideline of wheelchair design and develop medical instruments situation by using principles of engineering.
LTV-FIR command prefiltering for vibration reduction of a flexure-jointed X-Y motion stage with payload variation
Authors: Kuresangsai P. , Cole M. O. T.
Published: May 2021

This paper investigates the application of a linear-time-varying (LTV) command prefilter for vibration reduction in motion control of LTV systems. A model-based time-varying prefilter function is constructed that can be convolved with arbitrary command input signals to achieve residual vibration cancellation in a finite time. The prefilter is implemented on an experimental X-Y micro-positioning stage with a low-compliance flexure-jointed mechanism. Model coefficients within the LTV prefilter realization are varied in real-time according to measured platform position. As the dynamic model is also dependent on platform payload, a method is introduced to compensate for changes of payload mass based on the interpolation of model coefficients for extremum values. The results reveal that residual vibration can be cancelled effectively with settling time reduced from over 2 seconds to less than 0.4 seconds. Rapid point-to-point maneuvers over large travel distances, and with different known values of payload mass, can be achieved with high accuracy.
Penetration-force estimation approach for a flexure-jointed micro-injection mechanism with Lorentz force actuation
Authors: Sura A. , Kuresangsai P. , Cole M. O. T. , Wongratanaphisan T. , Puangmali P.
Published: May 2021

This paper presents a novel linear-motion compliant mechanism with Lorentz force actuation and integrated force-sensing capability for automated cell micro-injection. A model-based force estimation approach is introduced such that no force sensor is required. Model identification is undertaken by applying a sinusoidal actuation signal while the mechanism contacts with objects of known stiffness. Displacement data is then used to calculate model coefficients via a least-squares optimization. By using an observer-based state estimation scheme with actuation and displacement signals as inputs, force sensing accuracy within 70 μN RMS error could be achieved within a sensing range of 0 - 5 mN. This sensing capability confirms the suitability of the system for penetration force measurement in certain cases of cell micro-injection.
Orbital control for cube satellites
Authors: Thidrasamee Chayada , Wanichanon Thanapat
Published: May 2021

Today’s space technology is continuously developing so that sending satellites into space is not difficult anymore. Besides, satellites have emerged as powerful platforms for telecommunication, survey, and traffic information. For example, many countries have started to develop their satellites. Due to its compact size and uncomplicated system, a cube satellite is suitable as a starting point for the study and development of space technology. This research investigates the stability of a cube satellite with a small size, weighing less than 1 ton and orbiting in a Low-Earth Orbit (LEO) by using the Fundamental Equations of Constrained Motion (FECM) and Sliding-Mode Controller (SMC). The proposed controller guarantees motions of the satellite under the constraint that the satellite has to orbit in a circular trajectory in a Low-Earth Orbit (LEO) and able to handle unexpected changes. The MATLAB program was used to gather data from the numerical simulation. The result from the motion of the analyzing process is rather a remarkable outcome. It may help us to understand the satellite’s movement in a circular orbit with less and adjustable errors. This finding, while preliminary, suggests that we can cope with changes very well particularly the external high-frequency noise. Also, the values of the acceptable errors can be determined by adjusting the control parameters in the proposed controller.
Automatic precision docking for autonomous mobile robot in hospital logistics - case-study: battery charging
Authors: Vongbunyong S , Thamrongaphichartkul K , Worrasittichai N , Takutruea A
Published: May 2021

Autonomous Mobile Robots (AMRs) plays a vital role in various logistic applications, especially in the health industry. Precise localization is required for automated navigation of the robot throughout the operations. Docking is one of the key processes that the robot moves and physically attaches to the station. Higher precision in position and orientation is required for this process to ensure the secured connection. This article presents an implementation of precise docking maker technique for localization of the robot. The robot is equipped with affordable Lidar sensor while a geometrical marker is on the docking station. The proposed method should help the robot achieve better than ±20 mm error and 0.05rad error in position and orientation.