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Your search keyword '"Hokamoto, Kazuyuki"' showing total 153 results
Start Over Author "Hokamoto, Kazuyuki" Publication Type Academic Journals
153 results on '"Hokamoto, Kazuyuki"'

29. Explosive Welding of Aluminum and Cast Iron for Potential Transportation and Structural Applications.

Author

Sherpa, Bir Bahadur, Yu, Minghong, Inao, Daisuke, Tanaka, Shigeru, and Hokamoto, Kazuyuki

Subjects
EXPLOSIVE welding, ALUMINUM castings, IRON founding, DISSIMILAR welding, CAST-iron, LIGHTWEIGHT materials, FRACTURE strength
Abstract

This study explores the feasibility of explosive welding to join dissimilar materials: aluminum (JIS A1050‐H24) and two cast iron types (JIS G 5501 and JIS G 5502), which are challenging to weld due to the presence of graphite in the cast iron. Further, the impact of explosive thickness (28, 38, and 47 mm) on weld quality is investigated, considering microstructure and mechanical behavior. Increasing explosive thickness correlates with a thicker local melted zone. Remarkably, in investigations, a novel morphology that diverges from conventional patterns is observed. The weld interface of explosively bonded materials exhibits anchor formation, a unique interlocking structure. These anchors play a significant role in establishing a robust mechanism between bonded surfaces. JIS A1050‐H24 shows minimal hardness variation, while cast iron exhibits significant variations with increased explosive thickness. Tensile shear tests showcase robust clad plate strength, with fractures primarily in JIS A1050‐H24 regions instead of at the interface. The highest tensile shear strength is achieved with an explosive thickness of 38 mm. Overall, explosive welding of aluminum with cast iron creates a strong, durable, and lightweight material with enhanced performance characteristics, making it promising for diverse industrial applications due to its outstanding properties. [ABSTRACT FROM AUTHOR]

Published
2024
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37. Hypervelocity impact phenomena of LPSO-magnesium alloys

Author

Nishida Masahiro, Kodama Fumiya, Hayashi Koichi, Akahoshi Yasuhiro, Hokamoto Kazuyuki, and Kawamura Yoshihito

Subjects
Physics, QC1-999
Abstract

Hypervelocity impact phenomena of long period stacking ordered type magnesium alloys (LPSO-Mg) plates were examined at the impact velocities of 4 km/s and 6 km/s. Ejecta veil and external bubble of debris of LPSO-Mg were darker than those of aluminum alloy A6061-T6. The size of external bubble of debris of LPSO-Mg was slightly smaller than that of A6061-T6. The velocity reduction of LPSOMg was slightly larger than that of A6061-T6. However, the scatter area of projectile and targets were not determined by electron probe micro-analyzer.

Published
2018
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42. Improving the Efficiency and Antioxidant Activity of Essential Oil Extraction from Abies sachalinensis by Underwater Shockwave Pretreatment for the Construction of Low-Energy and Sustainable Essential Oil Extraction System.

Author

Kawai, Hideaki, Kuraya, Eisuke, Touyama, Akiko, Higa, Osamu, Tokeshi, Kazuki, Tsujikawa, Yoshie, Hokamoto, Kazuyuki, and Itoh, Shigeru

Subjects
ESSENTIAL oils, SHOCK waves, FIR, SUSTAINABLE construction, SUSTAINABLE development, NITROGEN dioxide
Abstract

Essential oils (EOs) from Abies sachalinensis (Sakhalin fir), a conifer species found in Sakhalin Island and Hokkaido in Japan, effectively remove nitrogen dioxide and possess antifungal activity. EOs also exert a relaxing effect and enhance air quality. Underwater shock waves generate instantaneous high pressure that ruptures cell walls, enhancing the performance of steam distillation and oil extraction. In this study, we aimed to increase the yield and quality of A. sachalinensis extracts using shockwaves. Leaves and branches were subjected to shockwave pretreatment or left untreated before EO extraction by steam distillation. EO yield of untreated dried leaves was 2.4 g/kg of dry leaf weight (DW). Upon application of a 3.0 kV, 3.6 kJ shockwave, the yield increased with the number of shockwave cycles. After ten cycles, yield increased 13.6-fold. Pretreatment with shockwaves for 10 cycles resulted in approximately 6- and 13-fold reductions in total energy consumption relative to fresh and dried leaves, respectively. Antioxidant activity increased more than 30-fold in shockwave-pretreated leaves than in untreated dried leaves after 10 cycles. This novel process can significantly reduce the energy used for EO extraction in steam distillation, thereby contributing to the development of a sustainable, low-energy EO production system. [ABSTRACT FROM AUTHOR]

Published
2022
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50. Mechanical Properties of Explosion-Welded Titanium/Duplex Stainless Steel under Different Energetic Conditions.

Author

Wang, Kang, Kuroda, Masatoshi, Chen, Xiang, Hokamoto, Kazuyuki, Li, Xiaojie, Zeng, Xiangyu, Nie, Senlin, and Wang, Yuanyuan

Subjects
DUPLEX stainless steel, MECHANICAL behavior of materials, TITANIUM, EXPLOSIVE welding, VICKERS hardness, IRON & steel plates
Abstract

In this study, the energy deposited at the welding interface was controlled by changing the stand-off between the flyer and base plates. Pure titanium (TP 270C) and duplex stainless steel (SUS 821L1) were welded under 5- and 15-mm stand-offs, respectively. When the stand-off was 5 mm, the average wavelength and average amplitude of the welding interface were 271 and 61 μm, respectively; at 15 mm stand-off, the average wavelength and average amplitude of the welding interface were 690 and 192 μm, respectively. The differences between the two welding conditions were compared using a tensile test, fracture analysis, a 90° bending test, Vickers hardness, and nanoindentation related to the mechanical properties of materials. The experimental results indicated that the sample with a 5-mm stand-off had better mechanical properties. [ABSTRACT FROM AUTHOR]

Published
2022
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