Article
Engineering, Aerospace
Deming Zhao, Zhisheng Cheng, Weiwei Zhang, Jinsheng Cui, He Wang
Summary: This paper presents a detailed thermal simulation analysis of the drilling process for icy soil in the lunar polar region. A multi-level particle size simulation model with a thermal sieve was developed to evaluate the temperature changes. The results show that the thermal conductivity of the sieve ranges from 100 to 400 W/m, and the addition of the thermal sieve significantly reduces the calculation time by 86%.
Article
Energy & Fuels
Armin Okati, Mohammad Reza Khani, Babak Shokri, Eliseu Monteiro, Abel Rouboa
Summary: The study focused on developing a computational model for evaluating the plasma gasification process of polychlorinated biphenyl wastes based on Gibbs free energy minimization. The results were satisfactory and validated by literature data. Various parameters such as temperature, equivalence ratio, steam-to-waste ratio, and carbon dioxide-to-waste ratio were found to significantly affect the production of syngas components.
Article
Thermodynamics
E. Inkeri, T. Tynjala, M. Nikku
Summary: Combining a heat pump with thermal energy storage is an efficient way to utilize variable renewable energy. This paper introduces a novel integration method for simultaneous consumption and charging of thermal energy storage using phase change materials. The concept is demonstrated in domestic hot water systems.
APPLIED THERMAL ENGINEERING
(2022)
Article
Engineering, Chemical
Haitao Lu, Jiajing Pan, Yu Gu, Junyi Xiao, Xiaofeng Hu, Long Tan, Mingli Lv
Summary: The powder deposition behavior and substrate surface evolution of the YSZ-NiCoCrAlY thermal barrier coating system were explored using a metal-ceramic bilayer powder deposition model. The results showed that the softening degree of NiCoCrAlY particles and YSZ particles differed, and their respective properties influenced the overall temperature and equivalent stress of the coating. The metal bond-layer served to protect the substrate and reduce the impact of the ceramic top-layer.
Article
Construction & Building Technology
Shu Jiang, Jun Li
Summary: A 3D numerical model was developed to analyze heat transfer and fluid motion characteristics in the quilt microclimate. Thirteen quilt configurations were constructed, and their impact on body heat loss was investigated. The findings provide insights into the heat transfer of bedding and can be used to assess the thermal performance of infant bedding.
BUILDING AND ENVIRONMENT
(2023)
Article
Computer Science, Interdisciplinary Applications
Christian Busse, Ilya Tsivilskiy, Joerg Hildebrand, Jean Pierre Bergmann
Summary: A customized code using OpenFOAM software was developed to simulate an inductively coupled plasma torch, effectively coupling magnetic field analysis and plasma numerical simulation. The validation results were obtained and compared with literature data, showing good agreement with commercial CFD codes.
COMPUTERS & FLUIDS
(2021)
Article
Thermodynamics
Guihua Fang, Pengbo Sun, Maosen Zhao, Wentao Zhang
Summary: This study prepared a series of paraffin-based ternary composite phase-change materials by combining paraffin with expanded graphite and nano-copper. The results showed that the addition of nano-copper significantly improved the thermal conductivity, heat storage and release rate of the composite materials. After 200 cycles, the phase-change temperature and storage capacity of the composite materials remained stable. Therefore, these composite phase-change materials are suitable for passive solar heating.
APPLIED THERMAL ENGINEERING
(2022)
Article
Spectroscopy
O. Gazeli, C. Lazarou, G. Niu, C. Anastassiou, G. E. Georghiou, J. Franzke
Summary: The study investigated a specific type of micro-tube plasma, known as the Flexible Micro Tube Plasma (F mu TP), experimentally and numerically for the first time. The creation, propagation mechanisms, and properties of ionization waves inside the microtube were examined during positive and negative half cycles of a microsecond square wave voltage. A 2D numerical model was developed and compared with optical emission spectroscopy, showing good agreement. The different propagation mechanisms during positive and negative half cycles affected the accumulation of charges, induced electric field, and speed of the ionization waves.
SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY
(2021)
Article
Engineering, Aerospace
M. Magarotto, S. Di Fede, N. Souhair, S. Andrews, F. Ponti
Summary: This work presents a numerical suite for cathodeless plasma thrusters, utilizing a Global Model, 3D-VIRTUS code, Starfish, and SPIS to estimate the propulsive performance and validate them against thrust measurements.
Article
Materials Science, Multidisciplinary
Guoliang Qin, Chao Feng, Hong Ma
Summary: Tandem TIG welding extends the existence time of liquid metal through thermal and mechanical control effects, preventing premature solidification and efficiently suppressing weld appearance defects.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Thermodynamics
Lu Qiu, Ahmed Kateb Jumaah Al-Nussairi, Azher M. Abed, Yaser Mohamed Hasan, Zuhair I. Al Mashhadani, Rahman S. Zabibah, Ayat Hussein Adhab, Emad Salaam Abood, As'ad Alizadeh, Roozbeh Sabetvand, Maboud Hekmatifar
Summary: This paper investigates the heat transfer capability of refrigerants inside a nanochannel using molecular dynamics simulation. By changing the heat flux and thermal conductivity, the thermal performance of different samples is examined. The results show that hydrocracked oil exhibits better thermal behavior and the addition of hybrid nanoparticles improves the thermal performance of the oil sample.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Article
Multidisciplinary Sciences
Dazhi Wang, Zeshan Abbas, Liangkun Lu, Xiangyu Zhao, Pengfei Xu, Kuipeng Zhao, Penghe Yin, Junsheng Liang
Summary: This paper presents a novel simulation work based on phase field method to explore the influence of various parameters on the stability and resolution of CE-Jet morphologies. Experimental validation is conducted to verify the optimized parameters for producing stable CE-Jet morphology.
SCIENTIFIC REPORTS
(2022)
Article
Astronomy & Astrophysics
S. A. Markovskii, Bernard J. Vasquez
Summary: This study investigates the elevated power peaks in magnetic spectra of solar wind at 1 au through statistical analysis and nonlinear numerical simulations. It is found that these peaks are mainly caused by thermal-ion instabilities and are only observed when the intensity of ambient turbulence is low. Furthermore, high intensity turbulence can suppress or obscure the instability, leading to a reduction in its saturation level.
ASTROPHYSICAL JOURNAL
(2022)
Article
Thermodynamics
He Liu, You Tian, Sohrab Alex Mofid, Shanshan Li, Junjie Zhou, Mengyao Hu, Bjorn Petter Jelle, Tao Gao, Xuehong Wu, Zengyao Li
Summary: Hollow silica nanosphere packings can suppress heat conduction significantly through voids, small interparticle contact areas, and nanosized pores, showing potential in energy-efficient building applications. Developing a numerical model considering geometric parameters can effectively reduce the thermal conductivity of HSNSPs.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Engineering, Chemical
Xiaoyu Zhang, Zishen Liu, Manabu Tanaka, Takayuki Watanabe
Summary: This study investigated the fabrication process of amorphous silicon nanoparticles by induction thermal plasma through experiments and numerical simulations. It was found that introducing additional quenching gas as counter-flow to the plasma tail flame enhanced the quenching effect, with the quenching rate increasing with the flow rate of the quenching gas. The results also showed that the amount of amorphous silicon increased with the injection of quenching gas, attributing to the improved preparation of small nanoparticles.
CHEMICAL ENGINEERING SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Yohei Abe, Takahiro Fujimoto, Mitsuyoshi Nakatani, Hisaya Komen, Masaya Shigeta, Manabu Tanaka
Summary: X-ray observation revealed welding phenomena during submerged arc welding, including droplet transfer, weld pool, and molten flux. Droplet transfer mode is spray transfer, and slag solidifies covering the surface of the weld pool.
SCIENCE AND TECHNOLOGY OF WELDING AND JOINING
(2021)
Article
Thermodynamics
Hisaya Komen, Masaya Shigeta, Manabu Tanaka, Yohei Abe, Takahiro Fujimoto, Mitsuyoshi Nakatani, Anthony B. Murphy
Summary: A two-dimensional axisymmetric heat source distribution was obtained through grid-based simulation, coupled with a particle method to verify the mechanisms of slag and weld pool formation and the thermal effects. The study revealed that the transport of molten metal and heat distribution in the weld pool significantly affect the quality of welding.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Chemistry, Physical
Y. Hirayama, M. Shigeta, Z. Liu, N. Yodoshi, A. Hosokawa, K. Takagi
Summary: By controlling the cooling rate using the low-oxygen induction thermal plasma process, both stable and metastable phases of anisotropic Nd-Fe ultrafine particles can be selectively prepared, with narrow particle size distribution and good crystallinity. The alloy powders obtained exhibit anisotropy and can be aligned by external magnetic field, paving the way for a new-generation anisotropic permanent magnet.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Multidisciplinary
Masaya Shigeta, Yusuke Hirayama, Emanuele Ghedini
Summary: This paper computationally investigates the effects of quenching on silicon nanoparticle growth processes and size distributions, revealing that in a highly supersaturated state, a significant portion of vapor atoms rapidly convert to nanoparticles and higher cooling rates result in smaller sizes and standard deviations.
Article
Chemistry, Physical
Kwangjae Park, Yusuke Hirayama, Masaya Shigeta, Zheng Liu, Makoto Kobashi, Kenta Takagi
Summary: This study successfully prepared a hard magnetic Sm-Co alloy nanopowder using the low oxygen-induction thermal plasma (LO-ITP) process, achieving spherical particles with an average diameter of 61 nm. The discovery of core/shell particles with a Co-core/Sm-Co-shell structure provides insights for improving magnetic properties. The results suggest potential strategies for enhancing the magnetic properties of Sm-Co alloy nanopowder.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Engineering, Chemical
Xiaoyu Zhang, Kentaro Yamano, Ririko Hayashida, Manabu Tanaka, Takayuki Watanabe
Summary: In this study, carbon coated silicon nanoparticles were prepared using induction thermal plasma, and the effect of methane injection methods was investigated. It was found that when the methane injection position was near the plasma torch, SiC, a byproduct that limits the battery capacity, was formed. By adjusting the methane injection position, the properties of the synthesized carbon coatings, including the sp(2) ratio and H content, could be controlled. These findings are important for the synthesis of carbon coated silicon nanoparticles and the design of high energy density lithium-ion batteries.
JOURNAL OF CHEMICAL ENGINEERING OF JAPAN
(2022)
Article
Chemistry, Physical
Y. Hirayama, M. Shigeta, K. Takagi, K. Ozaki
Summary: The composition of Ni-Cu alloy nanopowder prepared by a thermal plasma process was investigated. The experimental and computational studies showed that the nanoparticles in the powder have a homogeneous composition, but the composition distribution of the powder varies spatially.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Inorganic & Nuclear
Yiran Wang, Xiaoyu Zhang, Byeong-Il Min, Manabu Tanaka, Takayuki Watanabe
Summary: The synthesis of amorphous Li3BO3 was successfully conducted using induction thermal plasma, and the formation mechanism was systematically investigated. Various characterization techniques were employed to understand the morphology and chemical composition of the products. It was found that higher O2 and quenching gas flow rates resulted in a higher degree of amorphous Li3BO3, but also increased the possibility of by-product formation.
JOURNAL OF SOLID STATE CHEMISTRY
(2023)
Review
Physics, Applied
Masaya Shigeta
Summary: This article reviews and discusses the recent progresses of studies with the concept of Computational plasma fluid mechanics, emphasizing the importance of studying thermal plasma processes as comprehensive fluid systems. The computational simulations have successfully captured hydrodynamic instabilities, flow dynamics, and complex behaviors in thermal plasma-nonionized gas coexisting systems and molten metal during arc welding. The study highlights the indispensability of the viewpoint and approaches of fluid mechanics and plasma physics, and suggests that computational study will play an increasingly important role in providing new insights.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Physical
Yiran Wang, Byeong-Il Min, Manabu Tanaka, Takayuki Watanabe
Summary: Induction thermal plasma has been widely used for the synthesis of amorphous nanoparticles. In this study, amorphous Li4GeO4 nanoparticles were successfully synthesized by adjusting the Li/Ge molar ratio and quenching gas flow rate in the induction thermal plasma. The product morphology and chemical composition were characterized using transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. The formation mechanism was investigated based on experimental results and thermodynamic analysis. The results showed that an enhanced amorphous degree of Li4GeO4 nanoparticles could be achieved by controlling the Ge content and quenching rate.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Kenta Iida, Hisaya Komen, Masaya Shigeta, Manabu Tanaka
Summary: Droplet ejections from a molten tungsten electrode during AC TIG welding were observed using high-speed video, and the potential welding conditions and timings were investigated. The surface temperature of the electrode was also measured. A crater formed on the electrode surface, and droplet ejections occurred when the tip of the ridge growing from the crater separated. A series of droplet ejections occurred within a time scale of approximately 0.4 ms. The study showed that the high temperature of the electrode surface was the common factor for droplet ejections, and surface tension was the dominant force for changing the electrode shape.
Article
Engineering, Manufacturing
Muneyoshi Iyota, Tomoki Matsuda, Tomokazu Sano, Masaya Shigeta, Takahisa Shobu, Hirokatsu Yumoto, Takahisa Koyama, Hiroshi Yamazaki, Yasunori Senba, Haruhiko Ohashi, Shunji Goto, Ichiro Inoue, Yujiro Hayashi, Kenji Tamasaku, Taito Osaka, Jumpei Yamada, Makina Yabashi
Summary: Aluminum alloys are used to reduce the weight of automobile bodies. Controlling the state of intermetallic compounds during resistance spot welding (RSW) between steel and aluminum alloys is important. This study discusses the convection behavior of molten aluminum alloy during RSW and observes three types of convection as well as a correlation between convection behavior and the shape of the molten zone.
JOURNAL OF MANUFACTURING PROCESSES
(2023)
Article
Multidisciplinary Sciences
Kenta Iida, Hisaya Komen, Masaya Shigeta, Manabu Tanaka
Summary: A unique mechanism of splashing from a tungsten-based anode during arc discharge was discovered. The splashing occurred when a liquid metal column broke off after a local concavity formed on the molten anode surface. Blue-violet luminescence emitted by cerium ions from additives in the anode was observed before the formation of the concavity. The surface temperature exceeded the boiling point of the additives at the time of splashing.
SCIENTIFIC REPORTS
(2023)
Article
Multidisciplinary Sciences
Tomokazu Sano, Tomoki Matsuda, Akio Hirose, Mitsuru Ohata, Tomoyuki Terai, Tomoyuki Kakeshita, Yuichi Inubushi, Takahiro Sato, Kohei Miyanishi, Makina Yabashi, Tadashi Togashi, Kensuke Tono, Osami Sakata, Yoshinori Tange, Kazuto Arakawa, Yusuke Ito, Takuo Okuchi, Tomoko Sato, Toshimori Sekine, Tsutomu Mashimo, Nobuhiko Nakanii, Yusuke Seto, Masaya Shigeta, Takahisa Shobu, Yuji Sano, Tomonao Hosokai, Takeshi Matsuoka, Toshinori Yabuuchi, Kazuo A. Tanaka, Norimasa Ozaki, Ryosuke Kodama
Summary: This study reports the ultrafast lattice behaviour in iron shocked by a femtosecond laser pulse, revealing unique characteristics compared to conventional shock waves. The researchers found that the initial compression state caused by the femtosecond laser-driven shock wave is the same as that caused by conventional shock waves. They also experimentally observed the temporal deviation of peaks of stress and strain waves, as well as the existence of a plastic wave peak between them, which has not been predicted theoretically.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Multidisciplinary
Kazumasa Oshima, Hiromichi Kondo, Eriko Konishi, Tsuyoshi Yamamoto, Yoshifumi Tsuge, Takayuki Watanabe, Masahiro Kishida
Summary: The study investigated the effective removal of As(iii) from wastewater by catalytic oxidation to As(v) and precipitation with Fe(iii) ions. The combination of Pt/SiO2 catalyst and Fe(iii) precipitant improved the removal efficiency of As(iii) by functioning as both oxidation and precipitation sites.
