bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation on continuous FAME production using rotor reactor with bumpy number variation under theoretical methanol to oil molar ratio condition
Authors: Thaiyasuit Prachasanti , Khiowthong Wuttisan , Seehanam Wirapan 
Published: May 2021

Abstract
Continuous methyl ester production process from waste cooking oil (WCO) was studied by using a transesterification process at room temperature. The aim of this research was to investigate the optimized production conditions and specific energy consumption (SEW*h/kg of neat biodiesel) of the bumpy surface rotor reactor. There are 6.9%, 13.8%, and 27.6% of area fractions (AF) respectively. The reaction was under the condition being theoretical methanol to oil molar ratio and the reactor volume was 0.5L. At 2,000-4,000rpm of rotor speed, 1.0-1.5%w/w of KOH and 1.132-5.110L/min of precursor flow rate are used. It was found that the highest FAME content (fatty acid methyl ester in neat biodiesel, %) being 98.6%. It was achieved by using AF 27.6% rotor reactor under experimental conditions including 3,000rpm, 1.50%w/w of KOH and 2.027L/min of precursor flow rate. In addition, this condition gave SEC of 12.5W*h/kg. It was lower than that of orifice hydrodynamic cavitation reactor, power ultrasonic reactor, and mechanical stirring reactor around 93.2%, 95.0%, and 97.5% respectively. The properties of produced FAME met both EN 14214 and ASTM D 6751 standards.
Design for crash safety of electric heavy quadricycle structure
Authors: Kongwat Suphanut , Jaroenjittakam Suchanet , Chaianan Siravit , Atchariyauthen Intuch , Jongpradist Pattaramon 
Published: May 2021

Abstract
An electric small four-wheeler, categorized by the European Union as L7e so-called heavy quadricycle or microcar, is one of the solutions to eco-friendly and sustainable mobility for personal transport. Nonetheless, quadricycles typically do not offer the equivalent passive safety as larger passenger car models, in case of accidents, owing to the lack of energy absorption in the vehicle’s structure. This paper presents a proposed heavy quadricycle structure using plain weave carbon fibre-reinforced polymer in the passenger cell and aluminium alloy 6061-T6 in the crumple zone. The behaviors of electric heavy quadricycles under impact are simulated in accordance with the test guidelines of European New Car Assessment Programme using a non-linear finite element analysis via LS-DYNA to examine structural crashworthiness and characteristics. A full-frontal crash with a rigid wall at 30 km/h to 50 km/h shows that the front crush box, longerons and subframes in the crumple zone can efficiently absorb energy from a frontal crash up to 54.8%. The maximum damage in the structure occurs at the joints of the A-pillars and side beams to the front panel. Whilst the occupant safety space is safe under side collision by a 1350-kg moving deformable barrier at 50 km/h speed. However, the quadricycle tends to experience overturns from a side crash due to the vehicle’s lightweight and high center of gravity. Finally, suggestions for crashworthiness improvements to the composite passenger cell are provided based on the attained damage mechanism under a crash.
Analysis of aluminum front bumper beam for heavy quadricycles under impact loading
Authors: Phanmueang Kiadtikun , Jongpradist Pattaramon , Ruangjirakit Kitchanon 
Published: May 2021

Abstract
A heavy quadricycle is a small four-wheeled vehicle suitable for urban mobility owing to its compact, lightweight and energy-efficient advantages. However, such small vehicles have a comparatively short crumple zone leading to a higher risk of occupant injury in case of frontal collision. In this paper, the structural performance and energy absorption of aluminum alloy AA6063-T6 thin-walled front bumper beams for heavy quadricycles are studied. Mechanical characteristics of the beams with simple cross-sectional profiles, i.e., square, rectangle and double-cell rectangle as well as a commercially available bumper beam of a heavy quadricycle under cylindrical-rod impact loading are investigated through finite element analysis using LS-DYNA. A parametric study is also performed to examine the effects of open and closed sections, different cross-sectional shapes and various fillet radii on impact responses of the bumper beam including energy absorption, specific energy absorption, peak force, and crush force efficiency. The results show that although section profiles with sharp corners possess higher energy absorption, a larger fillet radius could mitigate the unfavourable peak force from impact up to 40%. The partition plate of the double-cell rectangle section induces a much higher peak force compared to others. In addition, when comparing an open-section beam with closed-section beams, it is found that an open-cell hat-shape model with fillet radius of 8 mm is the most efficient design. The crush force efficiency and peak force of the section are 32% higher and 17% lower, respectively, when compared to the closed-cell section with fillet radius of 8 mm.
Investigation of power transfer efficiency: utilizing different coil designs in wireless charging of electric vehicles
Authors: Thein M. E. , Charoensuk J. , Masomtob M. , Onreabroy W. , Kaewpradap A. 
Published: May 2021

Abstract
EV battery can be wirelessly charged by inductive coupling method between two electromagnetic couplers. In this study, the transmitter and receiver coils are designed. The effect of the number of turns for transmitter and receiver coils are studied. The results show that efficiency is decreased with the reduction of turns for both coils. Next, the spacing between each turn of coils is analyzed by 1mm of increasing for each simulation and the increased efficiency is only 2.6% for every 1mm spacing. Then, the power transfer efficiency is investigated for different coil designs. The efficiency can be improved with the proper consideration of air gap length, operation frequency, suitable coil designs and coil properties. Five coil designs such as circular, rectangular, double-D, double-D quadrature (DDQ) and bipolar designs are selected. The best design for maximum power transfer efficiency is DDQ design but the structure is complex since more wires are used in this design. The air-gap length between two coils is selected as 120mm and frequency is 85 kHz in this study.
Influence of axial force and characteristics of axial force affecting on total knee replacement constraint test
Authors: Musikul Tanapat , Kitkamthorn Usanee , Mitsomwang Pusit , Sindhupakorn Bura , Borrisutthekul Rattana 
Published: May 2021

Abstract
The result of testing for determination of Total Knee Replacement (TKR) Constraint (ASTM F1223) is necessary for surgeons for matching the knee prosthesis with the different degrees of severities of knee osteoarthritis patients. In the knee replacement constraint test, the axial compressive load and translation displacement are the control and the adjusting variables. The magnitude of axial compressive load during testing is affected by the slope of knee bearing surface. According to ASTM 1223 standard, the axial compressive load is not clarifyingly mentioned. Namely, it should be equal 710 N during testing or only in state of initiation. It may lead to testers to perform the test into different two modes which consequently in possibly different constraint result. Therefore, the objective of this research is to clarify the differences in test results when applying two axial compressive load characteristics during testing. The six-axis testing machine (Prosim Universal Joint Simulator) was used to determine the anterior posterior constraint (AP) of fix bearing posterior sacrifice (FB PS) system. Bovine serum was directly applied to the bearing surfaces as a lubricant. An initial axial compressive load 710 N was used. Two axial compressive load characteristics during testing, 1) keeping the axial force at given value as mentioned during testing (load-controlled testing) and 2) with allowing the change in axial compressive load during testing (displacement-controlled test), were used. From the results, the AP load resistance hysteresis loop patterns obtained by both testing modes were similar. The magnitude in forward direction load resistance is higher, while the backward AP load resistance showed the lower, in case of displacement control mode. It resulted in span between AP load resistance was larger. Moreover, the higher constraint in case of displacement control was indicated. Thus, if the test modes are not mentioned in test result, the surgeons will be possibly choosing the wrong TKR for their patient.
Stress analysis in upper fillet and rail-end bolt hole at rail joint
Authors: Le SaiKham , Wongsa-Ngam Jittraporn 
Published: May 2021

Abstract
Rail joint between two adjacent rail ends in the transportation of railway track structure is one of the weakest components leading to defects and failures. In this study, the rail joint components such as rail, joint bars, bolts, and sleeper are modelled by 3D Abaqus/CAE software and Finite-element method are used to investigate stress distribution in rail under static wheel load condition. The wheel load positions and bolt-hole locations vary as a parametric study. The results show that the critical stress occurs at the upper fillet rail end and at the edge of the rail-end bolt hole (1st hole from the rail end). The wheel load position affects stress only in case of the rail-end bolt hole located at 80 mm from the end. In addition, overall trends for the effect of rail-end bolt hole positions are similar in which the stress decreases when the distance from rail end to the rail-end bolt hole increases. Taken together, these findings suggest stress distribution is the basic information that helps understand the failure mechanism.
Line tracking control of royal Thai air force nursing mobile robot using visual feedback
Authors: Moudpoklang Jeerasak , Pedchote Chamnan 
Published: May 2021

Abstract
The specific objective of this study was to design a Royal Thai Air Force (RTAF) nursing robot, so-called Thadloom, to assist medical personnel in delivering food, medical supplies and communicating remotely with patients during the COVID-19 pandemic. This study also seeks to develop many identical mobile robots to be used in concerned places, such as hospitals or clinics, to reduce the risk of infection to medical personnel when entering the controlled area COVID-19-patients. This paper presents the design and implementation of real-time vision systems for the RTAF nursing robots when used in the controlled area of COVID-19-patients, with a capacity of delivering food and medical supplies automatically. The robots were able to follow lines on the floor using visual feedback. A contour tracing algorithm was implemented for line identification and position estimation. Linear segments with parabolic blends were used for the robot’s trajectory planning. The robot can track a line on the floor effectively by employing a PID controller. This experimental result showed that the developed vision-based state estimation and the designed PID controller. It was also found that it received a good satisfaction towards the accuracy of the position within 3.5 centimeters, i.e., The distance from the center of the robot to the center of the line.
Numerical investigation of air flow in a vertically paddy bed dryer using computational fluid dynamics
Authors: Chaiworapuek Weerachai , Chuenboonma Nuttakorn , Thungthong Teerapat , Munprom Ratiporn , Sae-tan Sudathip , Onwimol Damrongvudhi 
Published: May 2021

Abstract
This research focuses on the numerical investigation of air flow in a vertically paddy bed dryer using computational fluid dynamics - CFD. In this study, the Tubtim Chumphae paddy and perforated plates were assumed to be porous media and their properties were characterized experimentally in a 0.05 m × 0.05 m × 1 m duct. In this paper, the obtained porosity and permeability were applied to a numerical model, the air flow through a 100 kg paddy, stored in a vertical bed dryer. The results from the simulation and experiment agreed well with each other via the calibration process. The pressure drop across the dryer was found to increase when the inlet velocity gained from 0.025 to 0.1 m/s with an increment of 0.025 m/s. In this study, the results showed that air flow was controlled past the paddy with the deviation of less than 2.82% to achieve a high rice quality after the drying process. Because this drying technique used low temperature air and had low energy consumption, therefore, it is found to be one of the promising techniques and truly benefits the farmer in the future.
Energy management of precooling process for green cabbages
Authors: Naemsai Thanwit , Niyomvas Banyat , Jareanjit Jaruwat 
Published: May 2021

Abstract
Cold storage is one of the most widely used and effective processes to preserve shelf-life harvested agricultural products during long periods. Research to date has not yet determined the energy management of pre-cooling methods of green cabbage. This study seeks to investigate the cooling performance of the cold storage, keeping green cabbages with good quality and to report different pre-cooling strategies. The cold storage specifications included 15 HP compressor with a voltage of 380 V, a temperature range of -50 to 50°C, and R22 refrigerant. The mass of green cabbage was examined with three values of 30, 40, and 50 kg. Moreover, the pre-cooling strategies of the green cabbages were divided into four scenarios including the parallel pattern in the front zone, staggered pattern in the front zone, parallel pattern in the back zone, and staggered pattern in the back zone. The experimental results revealed that the coefficient of performance (henceforth COP) was significantly affected by the mass of the cabbage and cooling zone of the cold storage. While the pattern in case of 30 kg cabbage precooling had a slight effect on cooling performance due to the lower density arrangement and heat extraction. The highest COP appeared at the 30 kg cabbage precooling with the strategy of staggered pattern in the front zone. The COP value was 2.61.
Numerical study of performance augmentation of a vertical coil and shell heat exchanger using high frequency ultrasonic waves
Authors: Chaiworapuek Weerachai , Chungprempree Jirameth , Pukrushpan Jaytawee , Khaothong Kunthakorn 
Published: May 2021

Abstract
This research focuses on the performance augmentation of a coil and shell heat exchanger using high frequency ultrasonic waves by the commercial computational fluid dynamics program FLUENT. The model was validated both heat transfer and ultrasound propagation with the results from other researchers. Then, the simulation of the flow and heat transfer enhancement in the heat exchanger under 1.7 MHz ultrasound. Four ultrasonic transducers were installed at the corners of the shell at the middle height of the coil. The ultrasound from transducers was emitted to induce the vortex flow in the shell with the angle of 0, 15, and 30 degrees with the horizontal line. The results show that the high frequency ultrasound is applicable for heat transfer enhancement of a shell and coil heat exchanger. Therefore, the obtained results can be used to innovate an ultrasonic coil and shell heat exchanger in the future.
Effect of sodium hydroxide solution concentration on liquid entrainment in a steam boiler
Authors: Trinuruk Piyatida , Meekaew Somjate , Thong-in Ratchayothin , Satsananun Nut , Laklaem Thanapol 
Published: May 2021

Abstract
Liquid entrainment or carryover is a phenomenon that liquid droplets are carried out from a boiler or steam drum during steam generation. The droplets may convey some dissolved solids and cause damage to steam equipment such as scaling deposits in valves and steam piping and erosion of turbine blades. The appearance of dissolved solids in boiler water mainly comes from the internal water treatment process by dosing some chemical substances into the boiler in order to prevent corrosion and scale formation. Trisodium phosphate (Na3PO4) is one of chemical substances commonly added during boiler operation to control the pH of boiler water. However, it can cause the occurrence of sodium hydroxide (NaOH) solution which results in the increase of total dissolved solid (TDS) concentration in boiler water. Therefore, this study is aimed to develop a test section in order to investigate the parameters affected by liquid entrainment in the boiler. The experiment is performed in ambient conditions under an air-water system. Three variable factors are taken into consideration, including the concentration of NaOH solution, the height of the water level in the test tank, and the gas superficial velocity which represents the flow velocity of steam during steam generation. The results show that the increase of the gas superficial velocity and the water level height in the tank resulted in the enhancement of the entrainment rate. The increase of the water level height played an important role on the liquid entrainment. The increase of NaOH concentration directly impacted the existing film bubbles and the longer stability of foam bubbles at the water surface which resulted in a higher entrainment rate. Therefore, TDS control was one of the most important factors which could be incorporated with the appropriate height of the water level and the consistency rate of steam generation in order to minimize the liquid entrainment.
Understanding the adsorption behavior of small molecule in MoS2 device based on first-principles calculations
Authors: Jiang Wenfeng , Chen Kaifei , Wang Jiawei , Geng Di , Lu Nianduan , Li Ling 
Published: May 2021

Abstract
Although layered MoS2 has been proposed as a potential candidate for gas detection devices due to high surface-to-volume ratio, high sensitivity, and selectivity, the adsorption behavior of small molecules is still ambiguous. Here, we performed the first-principles calculations to investigate the adsorption behavior of small molecules on layered MoS2 surface, and the effects of defects and environment are considered. Our results reveal that NO and NO2 can be chemically adsorbed on defective monolayer MoS2, which is attributed to the forming of covalent bonds. And the forming of covalent bonds can lead to an increase in adsorption energies. Whereas, gas molecules can only be physically adsorbed on perfect MoS2. Meanwhile, as compared with adsorption behavior of NH3, NO, and NO2 on clean MoS2, the environmental gases (CO2, N2, and H2O) may result in an increase in adsorption strength of NH3, NO, and NO2 on MoS2 surface.
Effect of ball-milling process in combination with the addition of carbide microparticles on the microstructure and wear resistance of a Co–Cr–W alloy prepared by powder metallurgy method
Authors: Wang S Y , Hou X Y , Wang L , Zhang H Y , Zhang W B , Xia Y P , Sun Y , Zhou Y Z 
Published: May 2021

Abstract
Co–Cr–W alloys were widely used in the inlet exhaust valve of aeroengine. However, the traditional manufacturing process of Co–Cr–W alloys can not meet the demand for higher comprehensive performance, and an optimum method needs to be developed. Herein, a Co–Cr–W alloy reinforced by exogenous carbides was prepared by the powder metallurgy method. Effect of ball-milling time on the microstructure and wear resistance of the alloy was investigated, and the formation mechanisms of the reinforcing phases were discussed. Results showed that with prolonging the ball-milling time, the uniformity of the reinforcing phases was improved, grain refinement was achieved, the hardness increased, a suitable bonding interface was formed between the matrix and reinforcing phases, and better wear resistance was thus achieved. However, when the ball-milling time increased from 60 h to 70 h, local segregation of the reinforcing phases occurred, the hardness decreased from 64 HRC to 60 HRC, and the friction coefficient increased from 0.53 to 0.58. Based on our experimental results, we proposed two formation mechanisms of the reinforcing phases (carbides): In-situ precipitation from the matrix and in situ autogenic reaction between the elements of the matrix and the added carbides (WC and Cr3C2 particles). Both mechanisms contributed to the formation of M23C6 and M6C carbides. Our results underscore the importance of added reinforcing phases and help to optimize the ball-milling process in preparing the Co–Cr–W alloys.
The effects of sintering temperature on the mechanical properties and toughening mechanisms of carbon fibre-reinforced HfB2-SiC composites
Authors: Chen Yaxi 
Published: May 2021

Abstract
HfB2-SiC composites were fabricated by the introduction of carbon fibres to meet the mechanical requirements, and hot pressing was the sintering route. Experiments were carried out to study the effects of the sintering temperature on the mechanical properties and microstructure of HfB2-SiC composites with 15 vol% carbon fibres. In this study, the straight carbon fibres became curved during the pressing process, and the reasons were discussed. The mechanical results showed that curved fibres enhanced the fracture properties when the composites were sintered at temperatures below 1900 °C , and the toughening mechanisms, interfacial debonding, crack bridging and pull-out from the matrix were valid. When fibres are employed to improve the fracture toughness of other ceramics, bent fibres might be a common phenomenon, and this paper can provide important guidance to other researchers.
Daily Associations Between Positive Emotion and Obesity-Related Behaviors and Their Interconnections Within Adolescent–Caregiver Dyads
Authors: Cummings Caroline , Lansing Amy Hughes 
Published: May 2021

AbstractBackground Greater overall positive emotion has been linked with increased physical activity and overeating. High approach positive emotions (HAPEs), a subtype of positive emotion, are theorized to facilitate this goal-driven behavior. However, the day-to-day associations of HAPE and physical activity and overeating, including both at the individual level and within caregiver–adolescent dyads, remain unknown.Purpose We examined the independent and dyadic associations between HAPE (positive emotions that occur pregoal and motivate individuals toward approaching/acting upon that motive) and obesity-related behaviors, including physical activity and overeating, in adolescents and their primary caregivers.Methods Adolescents (N = 47) aged 11–17 and their caregivers completed demographic questions and a 7-day diary at the end of each day about daily emotion, and physical activity and overeating behaviors.Results For adolescents and their caregivers, increased day-to-day fluctuations in HAPE and greater average HAPE was associated with increases in their own daily physical activity levels. Greater average caregiver HAPE was also associated with increased overeating in caregivers. When examining interdependency within dyads, greater average caregiver HAPE was associated with greater adolescent overeating behavior.Conclusions There is evidence that HAPE is related to obesity-related health promoting behaviors and health risk behaviors in adolescence and adulthood. Future studies should further explore mechanisms underlying these associations, including within the family system.