Precise interferometric surface profiling of silicon wafer using sampling window and wavelength tuning

Journal of Mechanical Science and Technology - Phase-shifting fringe analysis using wavelength tuning has been widely applied to interferometric surface measurements of optical flats. However, when...     

Semantic Fire Segmentation Model Based on Convolutional Neural Network for Outdoor Image

Fire Technology - In this paper, we proposed a semantic fire image segmentation method using a convolutional neural network. The simple but powerful method proposed is middle skip connection...     

Molecular dynamics and inverse micromechanical study of thermoelastic properties of epoxy/POSS nanocomposites

Journal of Mechanical Science and Technology - A molecular dynamics simulation study was conducted to identify the contributions of polyoligosilsesquioxane (POSS) nanoparticles to the thermoelastic...     

Effect of nozzle temperature on the emission rate of ultrafine particles during 3D printing

Ultrafine particles and other hazardous materials are emitted during 3D printing, but the effect of temperature on such particles has not been studied systematically. The aim of this study was to evaluate the effect of temperature on the emission rate of particulate matter during fused deposition modeling (FDM) three-dimensional (3D) printing using different filament types. The number concentration of particles was measured with direct-reading instruments in an exposure chamber at various temperatures while using four filament materials during 3D printing. The temperature was increased from 185 to 290°C in 15°C increments, while incorporating the manufacturer-recommended operating conditions. The emission rate increased gradually as the temperature increased for all filament types, and temperature was the key factor affecting the emission rate after filament type. For all filaments, at the lowest operating temperature, the emission rate was 10⁷-10⁹ particles/min, whereas the emission rate at the highest temperature was about 10¹¹ particles/min, that is, 100-10 000 times higher than the emission rate at the lowest temperature. To reduce particle emissions from 3D printing, we recommend printing at the lowest temperature possible or using low-emission materials.     

Special issue on video and imaging systems for critical engineering applications [SI 1096]

Multimedia Tools and Applications -     

Synthesis of biodiesel from an oil fraction separated from food waste leachate

Biodiesel was produced from an oil fraction separated from food waste leachate, using a batch reactor system, to evaluate its potential as a renewable energy source for the first time. In order to reduce the free fatty acid content of the leachate oil fraction, three different acid catalysts, H₂SO₄, zeolite and Amberlyst-15, were used in the pretreatment process. The residual oil fraction after pretreatment was further treated over KOH as a base catalyst to produce a fatty acid methyl ester (FAME). The FAME content in the product was analyzed using GC/MS. A large number of different FAMEs were detected, which is characteristic of the food-waste-derived raw material used in this study. The FAME content of the product was highest when pretreated over Amberlyst-15, followed by trans-esterification. Additional refining and process optimization would be expected to further increase the FAME content. Therefore, it was concluded that the production of biodiesel from the oil fraction separated from food waste leachate is promising.     

Design of a Series Elastic Tendon Actuator Based on Gait Analysis for a Walking Assistance Exosuit

International Journal of Control, Automation and Systems - Exosuits are wearable robots that enhance a person’s muscular strength from outside the body. Many exosuits use tendon actuators...     

Flow Oscillations and Meniscus Fluctuations in a Funnel-Type Water Mold Model

Transient flows in a funnel-type continuous casting process model were studied experimentally to investigate the flow oscillations inside the mold and the meniscus fluctuations. A full-scale water model was used with dimensions of 2000 mm (length) × 1350 mm (width) × 100 mm (thickness). Particle image velocimetry (PIV) was employed to measure the flow oscillations. To minimize high shear flow errors near the submerged entry nozzle (SEN) exit, the window deformation technique was adopted. The meniscus levels were extracted by edge-detection image processing. Three types of SEN and two funnel thicknesses (180 mm and 220 mm) were tested to examine the flow characteristics under five flow rates (10, 20, 30, 40, and 50 m³/h). The vortex generation mechanism inside the mold was analyzed across the various mold conditions studied.     

CNT/PEDOT core/shell nanostructures as a counter electrode for dye-sensitized solar cells

CNT/PEDOT nanostructures composed of carbon nanotube (CNT) cores and poly(3,4-ethylenedioxythiophene) (PEDOT) shells were synthesized by chemical oxidative polymerization of 3,4-ethylenedioxythiophene (EDOT) using FeCl₃ and dodecylbenzene sulfonic acid (DBSA) as the oxidant and surfactant, respectively. The resulting CNT/PEDOT nanostructures had a PEDOT layer thickness of 2–5 nm that exhibited not only higher polymerization yield but also enhanced thermal stability and electrical conductivity relative to pure PEDOT. N-Methyl-2-pyrrolidone (NMP)-based CNT/PEDOT paste containing polyvinylidene fluoride (PVDF) as a binder was painted directly onto fluorine-doped tin oxide (FTO) glass for use as a counter electrode (CE) material in dye-sensitized solar cells (DSSCs). While DSSCs made of pure CNT and PEDOT CE exhibited power conversion efficiencies of ～3.88% and 4.32% under standard AM 1.5 sunlight illumination, respectively, the cell efficiency was enhanced to ～4.62% with the CNT/PEDOT CE. This enhancement was due to the improved fill factor of the CNT/PEDOT-based DSSC realized by the increased electrical conductivity of the CNT/PEDOT composite.     

Numerical Assessment for the Behavior of the Pleistocene Marine Foundations due to Construction of the 1st Phase Island of Kansai International Airport

A series of elasto-viscoplastic finite element analyses is performed to assess the stress and deformation of the Pleistocene marine foundation due to construction of the 1st phase island of Kansai International Airport in Osaka Bay. Attention is paid to the modeling of permeability for Pleistocene sand gravel layers considering the sedimentation environment because the performance of excess pore water pressure is strongly dependent on the extent of distribution as well as the change of thickness of those permeable sand gravel layers. The concept of “mass permeability” is introduced to model the actual process of dissipation of excess pore water pressure in the field. The mechanism for the propagation of excess pore water pressure is also discussed. Special attention is given to the modeling of the compressibility of the highly structured Pleistocene clay layers, exhibiting already significant visco-plastic deformations even in the quasi-overconsolidated effective stress range. The present numerical analyses are found to describe the large and long-term settlement together with the slow dissipation of excess pore water pressure in the Pleistocene clay and sand gravel layers that actually has taken place in the field. A detailed comparison of the distribution of excess pore water pressure and the differential compression for the individual Pleistocene clay layers shows that the calculated performance can well describe the actual behavior of the Pleistocene deposits due to the construction of the 1st phase island of Kansai International Airport.