Faculty Profiles - TSUKIYAMA Yosuke

Papers - TSUKIYAMA Yosuke

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Elucidation of frictional properties between rubber and flooring using a laser microscope with wide field of view

Isami Nitta, Takuto Masuda, Yosuke Tsukiyama

Tribology International 174 107775 - 107775 2022.10

Mechanical behaviour of porous metals fabricated by low-power selective laser melting

Isami NITTA, Ryota TAKAHASHI, Yosuke TSUKIYAMA

Journal of Advanced Mechanical Design, Systems, and Manufacturing 16 ( 5 ) JAMDSM0047 - JAMDSM0047 2022

Vibration insensitive single-shot interferometry using a wide-field laser microscope Reviewed

Isami Nitta, Yosuke Tsukiyama

Precision Engineering 2021.10

Realization of A Novel Morphing Surface using Additive Manufacturing and its Active Control in Friction

Motoyuki Murashima, Yusuke Imaizumi, Masato Kawaguchi, Noritsugu Umehara, Takayuki Tokoroyama, Toshiyuki Saito, Masayuki Takeshima, Yosuke Tsukiyama, Isami Nitta

Journal of Tribology 1 - 29 2021.2

Publishing type：Research paper (scientific journal) Publisher：ASME International

<title>Abstract</title>
As the need for higher efficiency of engineering components increases, so does the demand for functional surfaces. While various tribosurfaces (e.g., texturing and coatings) have been developed, many researches are aimed at static functionality. On the other hand, due to a wide range of environmental adaptability and active control, active-morphing surfaces can be highly efficient and robust. In this paper, we demonstrate a novel morphing surface and its realization using additive manufacturing (AM). By using a diaphragm structure, morphing performance is achieved even if a hard resin material is used. When air pressure is applied to the backside of the diaphragm, it changes to a convex shape, and vice versa. The concept requires a complex structure for arranging airflow and a solid morphing system. The AM is one great technique to create such complex structure. As a result of actual manufacturing, the created morphing structure realizes a large morphing of 600 µm or more. In addition, the shape changes reversibly depending on the air pressure. The surface also exhibits very interesting tribological characteristics. The surface shows a friction coefficient of 0.5-1.7 with a convexity, and then decreases to about 0.3 with a concavity. A real-contact area measurement reveals that the novel property occurs due to change in the real-contact area depending on surface morphology. In conclusion, the present paper provides a new concept of a novel morphing tribosurface, which selectively performs as a low-friction or break-like surface, created using AM.

DOI： 10.1115/1.4050269

Effect of power adhesion on the friction and wear of rubber rollers Invited

Yosuke Tsukiyama, Isami Nitta

TJTS2018 15 - 16 2018.11

Single-shot measurement of 3D surface profiles using wide field view laser microscope

Isami Nitta, Takuya Sato, Yosuke Tsukiyama

ICPE2018 2018.11

Influence of Paper Lint on Friction and Wear of Rubber Rollers

Yosuke Tsukiyama, Isami Nitta

ISPS/MIPE2018 2018.8

Visualization of contact patterns of thermal printhead for indirect thermal transfer printing Reviewed

Toshiki Irii, Masaya Kou, Yousuke Tsukiyama, Isami Nitta, Tomoko Wauke, Hirotoshi Terao

Journal of Advanced Mechanical Design, Systems, and Manufacturing 12 ( 2 ) JAMDSM0048 2018.5

A novel single shot interferometry with a wide field of view by reference plates coated with various metals Reviewed

Yuta Ohara, Yosuke Tsukiyama, Isami Nitta

Precision Engineering 52 345 - 355 2018.4

Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier Inc.

A laser microscope with a wide field of view developed in our previous study allowed us to observe the whole surface of a cylinder in a very short time. In that study, resolution of the laser microscope in the depth direction was sacrificed to obtain a wide field of view. To overcome this shortcoming and achieve nano-level measurement of 3-dimensional profiles of various objects, we have introduced two-beam interferometry to the wide field of view laser microscope. To achieve a high contrast interference fringe pattern, a glass reference plate was coated with a thin Cr film or other pure metals. The interference fringe pattern was distorted from sinusoidal wave into a sawtooth-like waveform. The distortion of the interference fringe pattern appeared to correspond to the inclination of the specimen surface measured. This shows the possibility of realizing a novel single shot interferometry method capable of determining the surface profile from only one image of the interference fringe pattern without using the phase shift method. The type of distortion of intensity distribution was different for each metal. The mechanisms by which the intensity distribution of the interference fringes changed to sawtooth pattern are discussed from both a Fourier-transform analysis and an electromagnetic approach.

DOI： 10.1016/j.precisioneng.2018.01.015

Laser microscope interferometer with wide field of view

Isami Nitta, Yosuke Tsukiyama

Toraibarojisuto/Journal of Japanese Society of Tribologists 63 ( 4 ) 276 - 279 2018

Proposal of lightweight and low starting torque slide bearing with looped carbon fibers brush Reviewed

Takuya SHITAKA, Motoyuki MURASHIMA, Noritsugu UMEHARA, Yosuke TSUKIYAMA, Isami NITTA, Hiroyuki KOUSAKA, Xingrui DENG

Transactions of the Japan Society of Mechanical Engineers 83 ( 854 ) 17-00252 - 00252-17-00252 2017.10

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Mechanical Engineers

<p>This paper addresses a novel lightweight and low starting torque bearing with looped carbon fiber brush (LCFB). LCFB simulates bristle of living being. Moreover, the static friction coefficient is nearly equal to the kinetic friction coefficient. By applying LCFB to a slide bearings, where a shaft is supported by multiple LCFBs, it is realized low starting torque bearings as well as lightness compared to conventional ball bearings. In this paper, we manufacture prototype LCFB slide bearings. With the bearings, we compare friction torque between LCFB slide bearings, slide bearings and deep groove ball bearings. As results, the ratio of starting torque to regular torque of LCFB slide bearing is from 0.93 to 1.07 which is smaller than that of the slide bearing. When micro-spline shaft is used as a mating material of LCFB slide bearing, the torque reduces because of decrease of real contact area between LCFB and mating materials. In addition, since LCFB utilize elastic deformation of fibers, LCFB slide bearings are not endurable in heavy radial load as high as load rating of ball bearing. Therefore, we define the load capacity of LCFB slide bearing from buckling load of a carbon fiber bundle to avoid overload state. We propose the load capacity as a design guideline of LCFB slide bearings.</p>

DOI： 10.1299/transjsme.17-00252

Laser micro texturing for high friction surface

Yosuke Tsukiyama, Honda Masanori, Tsuyoshi Kakiuchi, Yusuke Aida, Isami Nitta

ICOA2017 (International Conference on Optoacoustics) 2017.5

One-shot measurement of surface profile using wide field view laser microscope

Isami Nitta, Hirotoshi Watanabe, Yosuke Tsukiyama

ICOA2017 (International Conference on Optoacoustics) 2017.5

Frictional Property and Real Contact Area of Contaminated Rubber Rollers for Paper Feed

Yosuke Tsukiyama, Yohei Sato, Keisuke Kato, Isami Nitta

ICMDT2017 (The 7th International Conference on Manufacturing, Machine Design and Tribology) 220 2017.4

Proposal of new polyaxial locking mechanism of osteosynthesis plate

Hiroya Toyosaki, Yosuke Tsukiyama, Isami Nitta

ICMDT2017 (The 7th International Conference on Manufacturing, Machine Design and Tribology) 255 2017.4

A novel measurement method of real contact area of floor materials using ultra-high transparent rubber

Takuto Masuda, Yosuke Tsukiyama, Isami Nitta

ICMDT2017 (The 7th International Conference on Manufacturing, Machine Design and Tribology) 88 2017.4

広視野レーザ顕微鏡による円筒内外面とカムの全周観察 Reviewed

新田勇, 福島直幸, 江渕倫太郎, 月山陽介

精密工学会誌 82 ( 11 ) 976 - 982 2016.11

Contact thermal resistance of densely-packed VACNTs and deformation mechanics of CNTs

Yosuke Tsukiyama, Takumi Kawasaki, Isami Nitta, Wataru Norimatsu, Michiko Kusunoki

International Conference on Diamond and Carbon Materials 2016.9

Evaluation of transformed layer hardness of DLC coating after friction test Reviewed

Nor Azmmi Masripan, Yosuke Tsukiyama, Kenji Ohara, Noritsugu Umehara, Hiroyuki Kousaka, Takayuki Tokoroyama, Shigeru Inami, Koji Zushi, Masahito Fujita

Jurnal Teknologi 78 ( 10-3 ) 43 - 47 2016

Language：English Publishing type：Research paper (scientific journal) Publisher：Penerbit UTM Press

Diamond-like carbon (DLC) provide very excellence performance in term of friction coefficient and wear resistance under boundary lubrication. the nano characteristic of the transformed layer has not been studied in terms of its hardness which is believed to have a significant effect in the tribological performance. This study presented the scratch test of the DLC transformed layer was obtained from the AFM scratch test that governs the friction behavior of DLC. As a result, the hardness of the DLC transformed layer depends on the oil temperature, where the sliding interface of DLC softened during the friction test due to graphitization process.

DOI： 10.11113/jt.v78.9761

Fundamental study of acoustic leakage through a gap between gasket and flange surface Reviewed

Shuichi Sakamoto, Takanari Azami, Isami Nitta, Yosuke Tsukiyama

JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING 10 ( 4 ) JAMDSM0067 2016

Language：English Publishing type：Research paper (scientific journal) Publisher：JAPAN SOC MECHANICAL ENGINEERS

In this study, we theoretically and experimentally explore the acoustic leak of an entire acoustic system as well as the various gap occurring between a gasket and flange. We conducted the first-ever fundamental research related to sound transmission loss through a narrow gap between a gasket and flange. In the experiments, we constructed pipeline elements, including the gap and the leakage path, in the impedance measurement tube. In the theoretical analysis, we replaced the fluid path, including the gap, with acoustic elements that comprise an electrical equivalent circuit. We then conducted the analysis using the transfer matrix method. To calculate the attenuation of sound waves propagating through the gap, we considered friction in association with viscosity, primarily in the boundary layers of the inner wall, to derive the characteristic impedance and propagation constant. The trends between the calculated and the actual experimental values for transmission loss in the entire acoustic system coincided enough with regard to a large gap size range between 0.01 and 0.2 mm. Furthermore, the transmission loss linearly increased with the decreasing logarithm of gap for the calculated regions. Furthermore, the theoretical analysis and experimental results show agreement for incline gap conditions between the gasket and flange. The maximum gap also greatly affects the acoustic transmission loss for the inclined gaps. This was confirmed both by the experimental and the calculated values. We consider that these results provide fundamental acoustic knowledge specific to the narrow gap between the gasket and flange in an acoustic system.

DOI： 10.1299/jamdsm.2016jamdsm0067

Frictional characteristics of clamp surfaces of aneurysm clips finished by laser processing Reviewed

Isami Nitta, Yosuke Tsukiyama, Satoshi Nomura, Noboru Takatsu

JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING 10 ( 2 ) JAMDSM0026 2016

Language：English Publishing type：Research paper (scientific journal) Publisher：JAPAN SOC MECHANICAL ENGINEERS

An aneurysm clip is a medical instrument that is used intraoperatively to clip a ruptured cerebral aneurysm and reduce the risk of rebleeding. To prevent the clips from slipping off the aneurysm neck, it is very important to maintain a constant clamp force. A high frictional coefficient of the clip blades will also help prevent slippage between the clip blades and the blood vessel. In this study, to raise the frictional coefficients of the clip blades, we used a laser processing machine to produce clamp surfaces of the aneurysm clips with micro-dimples or micro-grooves. The static and dynamic frictional characteristics of the clamp surfaces made in this way were examined. The grooved surfaces with a width of 30 mu m and a groove pitch of 40 mu m showed the highest frictional coefficient. However, the dimpled surfaces with a shallow depth of 1 mu m showed lower frictional coefficients than existing aneurysm clips.

DOI： 10.1299/jamdsm.2016jamdsm0026

Nanoscale measurement of whole cylinder surface using a laser microscope with a wide field of view Reviewed

TSUKIYAMA Yosuke, FUKUSHIMA Naoyuki, NITTA Isami

Journal of the Japan Society for Precision Engineering 81 ( 7 ) 699 - 704 2015.7

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japan Society for Precision Engineering

In a previous study, we developed a new method for observation of the whole cylindrical surface in a very short time,using a laser microscope with a wide field of view. When cylindrical specimens were rotated by a motor-driven rotary table, the focused laser light was scanned along a generatrix of the cylinder surface. Thus, the whole cylinder surface could be observed easily even over a very short time. As the obtained image was a developed view of the cylinder surface, it was easy to measure the distance between any two points on the cylindrical surface. In this study, we acquired interference images of the whole cylinder surface with the aid of a reference plane. As a result, fringe patterns over the whole cylinder surface could be obtained. From image processing of the fringe patterns, we calculated the nanoscale surface profile of the cylinder.

DOI： 10.2493/jjspe.81.699

Relationship Between Friction Force and Real Contact Area Observed by Laser Microscope with Wide Field of View

Yosuke Tsukiyama, Naoya Fukuda, Takuto Masuda, Isami Nitta

ICMDT2015 (The 6th International Conference on Manufacturing, Machine Design and Tribology) 70 - 71 2015.4

Effect of laser micro texturing on the frictional properties of Ti material

Yusuke Aida, Masanori Honda, Tsuyoshi Kakiuchi, Yosuke Tsukiyama, Isami Nitta

ICMDT2015 (The 6th International Conference on Manufacturing, Machine Design and Tribology) 294 - 295 2015.4

Nanoscale Measurement of Whole Cylinder Surface using a Wide Field-of-View Laser Interferometer

Isami Nitta, Yosuke Tsukiyama, Shunsuke Sakuma

ICMDT2015 (The 6th International Conference on Manufacturing, Machine Design and Tribology) 426 - 427 2015.4

Evaluation of transformed layer of DLC coating after friction test using Atomic Force Microscopy (AFM) Reviewed

N. A. B. Masripan, Y. Tsukiyama, K. Ohara, N. Umehara, H. Kousaka, T. Tokoroyama, S. Inami, K. Zushi, M. Fujita

PROCEEDINGS OF MALAYSIAN INTERNATIONAL TRIBOLOGY CONFERENCE 2015 32 - 33 2015

Language：English Publishing type：Research paper (international conference proceedings) Publisher：MALAYSIAN TRIBOLOGY SOC-MYTRIBOS

Diamond-like carbons (DLC) with hardness of 47.1 GPa were coated on SUJ2 rollers, and their tribological properties were investigated after friction test under boundary lubrication conditions in an additive-free mineral-based oil at different testing oil temperatures of 24, 80 and 160 degrees C. From the results of the Raman analyses and Spectroscopy ellipsometry, we found that the structure changed of DLC at the topmost of sliding surface and their thickness will measured using AFM. It is found that the transformed layer increased with increases of testing oil temperature.

Prologue to the Special Issue on "Up-and-Coming Tribologists"

TSUKIYAMA Yosuke

JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS 60 ( 2 ) 90 - 90 2015

Measurement of real contact area on thermal print head using a laser microscope with a wide field of view Reviewed

Isami Nitta, Yosuke Tsukiyama, Tsuyoshi Tsukada, Hirotoshi Terao

TRIBOLOGY INTERNATIONAL 79 162 - 173 2014.11

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI LTD

In a dye-sublimation printer, a thermal print head presses and heats a dye-based ribbon to diffuse ink dyes to the desired positions into the receiving layer of paper. The print quality will deteriorate if the contact condition between the thermal print head and the paper is insufficient. Thus, it is necessary to analyze the contact condition for finer printing. Direct observation of the contact area with an optical microscope is effective to clarify the contact conditions of the thermal print head. However, conventional optical microscopes take too much time to observe the whole apparent contact area, because their fields of view are not sufficiently wide. Previously, we developed a laser microscope with a wide field of view and applied this laser microscope to observe the whole apparent contact area of rubber elements. In this study, we examined the contact conditions between the thermal print head and the paper. In general, when we observe the contact area of two solid surfaces, one is restricted to a transparent material such as a glass plate. Instead of the thermal print head, a glass head of the same shape as an existing thermal print head was pressed on the paper and observed through the glass head. This allowed us to clearly determine the contact situations of the interface and measure the contact widths and distributions of real contact area. In this method, it was confirmed that the contact width and the real contact area changed in accordance with the type of paper used, steps of the printing process, and density of color printing. (C) 2014 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.triboint.2014.06.005

鉄道車両用レーザ三次元座標測定システムのデータ接続手法の開発 Reviewed

月山陽介, 菅野明宏, 新田勇, 大川永, 鈴木正毅, 久保田遼, 西脇正, 磯部光一

精密工学会誌 80 ( 7 ) 675 - 681 2014.7

Nanoscale measurement of whole cylinder surface with laser microscope with wide field of view

Isami Nitta, Yosuke Tsukiyama, Naoyuki Fukushima

ICPE2014 (15th International Conference on Precision Engineering) 830 - 835 2014.7

Evaluation of sealing characteristics of copper gasket using laser microscope with wide field of view Reviewed

NITTA Isami, MATSUZAKI Yoshio, TSUKIYAMA Yosuke, HORITA Motoshi, SAKAMOTO Shuichi

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A 80 ( 814 ) DSM0173 - DSM0173 2014.6

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Mechanical Engineers

To quantitatively predict leakage rates through gasket/flange interface, it is important to observe contact conditions at seal surfaces because the leakage path consists of the non-contact portions between the flange and gasket surfaces. The contact surfaces of the flanges were finished by lathe turning. In this study, we observed real contact area on gasket surfaces using a laser microscope with a wide field of view. The observations indicated that the leakage paths on the gasket surfaces were in the radial direction perpendicular to a lathe-turned groove and the circumferential direction along the groove. As the closing loads increased, the leakage paths in the radial direction disappeared and only the leakage path in the circumferential direction remained. The critical contact pressure where the leakage paths in the radial direction disappear was determined from the observation of the contact surface of the gasket. Over the critical contact pressure, the leakage rates obtained from the experiments showed good agreement with the calculated values under the assumption of laminar flow along the turned groove. Under the critical contact pressure, the recalculated values considered the leakage paths in both the radial and circumferential directions approached the experimental values.

DOI： 10.1299/transjsme.2014dsm0173

レーザスポット走査型干渉計の開発－小型レンズ金型の形状計測－ Reviewed

本合邦彦, 月山陽介, 鈴木天, 新田勇

精密工学会誌 80 ( 3 ) 302 - 307 2014.3

Evaluation of tribological properties of pick up roller measured using a laser microscope with a wide field of view Reviewed

Isami Nitta, Yosuke Tsukiyama, Tsuyoshi Tsukada, Hirotoshi Terao

TRIBOLOGY INTERNATIONAL 67 182 - 190 2013.11

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI LTD

Analysis of contact conditions between rubber rollers and printing paper is important for stable paper feeding operation. Direct observation of apparent contact area is necessary to understand contact conditions, such as distributions of real contact area and micro-slips. However, conventional optical microscopy takes too long to observe the whole apparent contact area because the field-of-view is too narrow. We developed a wide field-of-view laser microscope, and applied it to determine the distributions of real contact area of rubber rollers against glass plates. Critical torques at which micro-slips of the rubber rollers occurred were proportional to total real contact area. (C) 2013 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.triboint.2013.07.014

Thorough Observation of Real Contact Area of Copper Gaskets Using a Laser Microscope With a Wide Field of View Reviewed

Isami Nitta, Yoshio Matsuzaki, Yosuke Tsukiyama, Motoshi Horita, Shuichi Sakamoto

JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME 135 ( 4 ) 041103-1 - 041103-7 2013.10

Language：English Publishing type：Research paper (scientific journal) Publisher：ASME

To quantitatively predict the leakage rates of static metal seals, it is important to observe the real contact area at seal surfaces because the leakage path consists of the noncontact portions between the flange and gasket surfaces. In a previous study, we observed the real contact situation using a thin polymer film 1 mu m in thickness. In the present study, we observed the real contact area on gasket surfaces using a laser microscope with a wide field of view. With this method, observation time over the whole gasket surface could be greatly reduced compared with conventional methods. The observations indicated that the leakage paths on the gasket surfaces were in the radial direction perpendicular to a lathe-turned groove and the circumferential direction along the groove. As the closing loads increased, the leakage paths in the radial direction disappeared and only the leakage path in the circumferential direction remained. When the closing loads increased further, the widths of the leakage paths at both the inside and outside on the gasket surface became narrower. The critical contact pressure where the leakage paths in the radial direction disappear was determined from the observation of the contact surface of the gasket. The leakage rates obtained from the experiments showed good agreement with the calculated values under the assumption of laminar flow along the turned groove over the critical contact pressure.

DOI： 10.1115/1.4024781

Observation of the real contact area of carbon nanotube film

Yosuke Tsukiyama, Naoya Fukuda, Isami Nitta, Wataru Norimatsu, Michiko Kusunoki

World Tribology Congress 2013 2013.9

Observation of Spherical Surfaces using a Laser Microscope with Wide Field of View

Isami Nitta, Yosuke Tsukiyama, Takuya Watanabe, Naoyuki Fukushima

World Tribology Congress 2013 2013.9

Measurement of surface profile of precision molds using a newly developed scanning laser interferometer

Kunihiko Hongo, Hiraku Suzuki, Yosuke Tsukiyama, Isami Nitta

ICMDT2013 (The 5th International Conference on Manufacturing, Machine Design and Tribology) 207 2013.5

Contact Behavior of Vertically Aligned Carbon Nanotube film

Yosuke Tsukiyama, Naoya Fukuda, Isami Nitta, Wataru Norimatsu, Michiko Kusunoki, Noritsugu Umehara

ICMDT2013 (The 5th International Conference on Manufacturing, Machine Design and Tribology) 152 2013.5

Observation of Spherical Heart-Valve Prosthesis using a Laser Microscope with Wide Field of View

Isami Nitta, Yosuke Tsukiyama, Naoyuki Fukushima, Takuya Watanabe

ICMDT2013 (The 5th International Conference on Manufacturing, Machine Design and Tribology) 64 2013.5

Effect of texturing on friction properties of CNx coating layer under oil lubrication with imitation wear debris Reviewed

Takayuki Tokoroyama, Tomoyo Kaneko, Yosuke Tsukiyama, Noritsugu Umehara, Tetsuya Sato, Tadashi Suzuki

Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C 79 ( 806 ) 3895 - 3903 2013

Language：Japanese Publishing type：Research paper (scientific journal)

Frequent contacts between bearing balls or needles and its guide generate friction heat, and it is not demanded because oil viscosity becomes low, then oil film thickness decreases. In such case, direct contact between mating surfaces occurs in the real contact area. To prevent wear by direct contacts, high wear proof and low friction coefficient of hard carbon coating is demanded. However, in the case of wear particles which are generated from hard carbon coating, the particles become wear promotion elements of bearing surfaces. Therefore, a surface shape modification is important to eliminate wear particles from contact area. In this paper, we prepared CNx (Carbon Nitride) coating deposited on surface with texturing to reduce friction coefficient by wear particles which were lied between mating surfaces. Friction tests were carried out at mixed and boundary lubrication condition with VG100 oil. We applied glass beads as imitation wear particles. In the boundary lubrication condition, the CNx coated surface showed friction coefficient of 0.058 in only VG100 lubrication. On the other hand, the friction coefficient was approximately 0.12 without CNx coating in VG100 lubrication. In the case of friction test with glass beads, it was clarified that 40 μm width and 20 μm depth texturing with 32 lines showed lowest friction coefficient when the specimen slid against counter material. © 2013 The Japan Society of Mechanical Engineers.

DOI： 10.1299/kikaic.79.3895

Clarification of hysteresis mechanism in the indentation of the high-densed carbon nanotube film Reviewed

Masaharu Wakayama, Yosuke Tsukiyama, Takayuki Tokoroyama, Hiroyuki Kousaka, Noritsugu Umehara

Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C 79 ( 801 ) 1821 - 1826 2013

Language：Japanese Publishing type：Research paper (scientific journal)

The Carbon Nanotubes have been reported to show hysteresis curves by Nano-indentation tests. To clarify the mechanism of this hysteresis, we conducted Nano-indentation tests to CNT films by using two diamond tips with different curvature radii. The AFM Nano-indentation was to perform penetration of diamond tip into CNT film, which means generation of friction force between diamond tip aspect and CNT tubes aspect. On the other hand, in the case of using spherical diamond tip by which cyclic Nano-indentation tests were conducted, the load-displacement curves became similar to those of carbonaceous coatings. This means that cyclic indentation for CNT made it like continues material. However, after several cyclic Nano-indentation tests to same position, the CNT specimen still showed hysteresis curve. These results indicated that hysteresis of CNT by Nano-indentation was related to friction between CNT tubes each other. © 2013 The Japan Society of Mechanical Engineers.

DOI： 10.1299/kikaic.79.1821

Characteristics of the transformed layer of DLC after friction testing under boundary lubrication in additive-free mineral based oil

Nor Azmmi Bin Masripan, Yosuke Tsukiyama, Kenji Ohara, Noritsugu Umehara, Hiroyuki Kousaka, Takayuki Tokoroyama, Shigeru Inami, Koji Zushi

5th World Tribology Congress, WTC 2013 1 646 - 649 2013

Evaluation of Sealing Characteristics of High-Performance Gasket Using a Laser Microscope with Wide Field of View

Yoshio Matsuzaki, Isami Nitta, Yosuke Tsukiyama

17th ISC (International Sealing Conference) 329 - 338 2012.9

Effects of Paper Debris on Micro-Slip Characteristics of Rubber Rollers

Isami Nitta, Tsuyoshi Tsukada, Yosuke Tsukiyama

ITC Hiroshima 2011 2011.11

The Influence of Interlayer for Frictional Property and Adhesion of IBAD CNx Coating Reviewed

Masaharu WAKAYAMA, Yosuke TSUKIYAMA, Takayuki TOKOROYAMA, Hiroyuki KOUSAKA, Noritsugu UMEHARA, Mei WANG, Takaomi TOIHARA

Transactions of the Japan Society of Mechanical Engineers. C 77 ( 781 ) 3502 - 3510 2011.9

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Mechanical Engineers

The carbonaceous hard coating such as Diamond-Like Carbon is one of the materials to prevent surface damage. It was reported that Carbon Nitride (CNx) coating showed superlow friction coefficient when it slid against a Si<sub>3</sub>N<sub>4</sub> ball in N<sub>2</sub> environment. In the case of applying CNx coating for industrial fields, it is necessary to improve adhesion between CNx coating and substrate. In this study, we clarify the effect of interlayer to improve adhesion of CNx coating to WC substrate. 4 different kinds of interlayer materials were prepared. From the scratching test results, adhesion of using CrN and no interlayer was smallest. On the other hand, SiN, CN and DLC interlayers showed high adhesion. From the finite element analysis, interlayer thickness and Young's modulus did not affect to improve adhesion between CNx coating and WC substrate.

DOI： 10.1299/kikaic.77.3502

Review on Japanese-German-US Cooperation on Laser-Ablation Propulsion Reviewed

Stefan Scharring, John E. Sinko, Stephanie Karg, Hans-Albert Eckel, Hans-Peter Roeser, Akihiro Sasoh, Naoya Ogita, Noritsugu Umehara, Yosuke Tsukiyama

BEAMED ENERGY PROPULSION: SEVENTH INTERNATIONAL SYMPOSIUM 1402 47 - 61 2011

Language：English Publishing type：Research paper (international conference proceedings) Publisher：AMER INST PHYSICS

We report on an international cooperation between Nagoya University (NU), Japan and DLR Stuttgart, Germany on scaling issues in laser ablative propulsion. Lessons learned from collaborative work in the laboratory will be summarized with respect to the comparability of experimental methods and corresponding standardization issues. With the background of previous experimental research at the University of Alabama in Huntsville (UAH), experimental work with CO2 lasers in a moderate (NU) and high (DLR) pulse energy range on laser ablation of POM is presented. Profilometry results of target surfaces are compared with fluence distributions from beam propagation modeling. Ablation from flat targets is reported with respect to energy and area scaling and compared with results from ablative propulsion employing parabolic nozzles.

DOI： 10.1063/1.3657015

Nanowear Characteristics of Carbon Nanotube Film Made by Surface Decomposition of SiC Reviewed

Yosuke Tsukiyama, Noritsugu Umehara, Michiko Kusunoki

JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING 4 ( 1 ) 373 - 382 2010

Language：English Publishing type：Research paper (scientific journal) Publisher：JAPAN SOC MECHANICAL ENGINEERS

This paper shows the wear characteristics of carbon nanotube films made by surface decomposition of SiC. By this method, one can obtain remarkably high density of CNTs with well vertical alignment. For the purpose of measuring the wear characteristics of CNT films with submicrometer thickness, we carried out nanoscratch and nanoindentation tests by using an atomic force microscope (AFM). And we used 2 kinds of AFM cantilever tips with tip radii of about 20 nm and 150 nm. The experimental results showed wear behaviors of CNT films dependent on CNT length and normal load. And CNT films were worn gradually as the number of wear cycles increased. The effect of CNT length on wear of CNT films appeared as different behaviors of CNT films under normal load. That was originated from bending stiffness of each CNTs with different length as measured by nanoindentation. Shorter-CNT films had less wear because of higher deformation resistance than longer ones. Under the normal load, the SCD tip penetrated to several tens of nanometers in depth, but the CNT films showed only wear depth on the order of angstrom for each scratch cycle. Thus we confirmed that CNT films have both strength and flexibility, which reflects remarkable mechanical properties of CNTs. These results are important for machine designs using CNT films as friction materials.

DOI： 10.1299/jamdsm.4.373

Critical Fluences And Modeling Of CO2 Laser Ablation Of Polyoxymethylene From Vaporization To The Plasma Regime Reviewed

John E. Sinko, Claude R. Phipps, Yosuke Tsukiyama, Naoya Ogita, Akihiro Sasoh, Noritsugu Umehara, Don A. Gregory

BEAMED ENERGY PROPULSION 1230 395 - + 2010

Language：English Publishing type：Research paper (international conference proceedings) Publisher：AMER INST PHYSICS

A CO2 laser was operated at pulse energies up to 10 J to ablate polyoxymethylene targets in air and vacuum conditions. Critical effects predicted by ablation models are discussed in relation to the experimental data, including specifically the threshold fluences for vaporization and critical plasma formation, and the fluence at which the optimal momentum coupling coefficient is found. Finally, we discuss a new approach for modeling polymers at long wavelengths, including a connection formula that links the vaporization and plasma regimes for laser ablation propulsion.

CO2 Laser Ablation Propulsion Area Scaling With Polyoxymethylene Propellant Reviewed

John E. Sinko, Katsuhiro Ichihashi, Yosuke Tsukiyama, Naoya Ogita, Takeharu Sakai, Noritsugu Umehara, Akihiro Sasoh

BEAMED ENERGY PROPULSION 1230 207 - + 2010

Language：English Publishing type：Research paper (international conference proceedings) Publisher：AMER INST PHYSICS

The topic of area scaling is of great importance in the laser propulsion field, including applications to removal of space debris and to selection of size ranges for laser propulsion craft in air or vacuum conditions. To address this issue experimentally, a CO2 laser operating at up to 10 J was used to irradiate targets. Experiments were conducted in air and vacuum conditions over a range of areas from about 0.05-5 cm(2) to ablate flat polyoxymethylene targets at several fluences. Theoretical effects affecting area scaling, such as rarefaction waves, thermal diffusion, and diffraction, are discussed in terms of the experimental results. Surface profilometry was used to characterize the ablation samples. A CFD model is used to facilitate analysis, and key results are compared between experimental and model considerations. The dependence of key laser propulsion parameters, including the momentum coupling coefficient and specific impulse, are calculated based on experimental data, and results are compared to existing literature data.

Evaluation of mechanical properties of the superficial layer of CNx with ultra low friction in N2 gas Reviewed

Norihiro Kimura, Yosuke Tsukiyama, Takayuki Tokoroyama, Noritsugu Umehara

Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C 76 ( 772 ) 3794 - 3799 2010

Language：Japanese Publishing type：Research paper (international conference proceedings) Publisher：Japan Society of Mechanical Engineers

Carbon nitride (CNx) coating is one of the carbonaceous materials, which was reported to show superlow friction coefficient (μ&lt
0.009) in Nitrogen environment. Therefore CNx coating is a promising material of solid lubricant for sliding interfaces to reduce friction. The superlow friction appeared after running in process of several hundreds of friction cycles and its mechanism has not been completely clarified yet. It was proposed that the soft thin layer generated on CNx coating after running-in process contributed to the superlow friction. However, the mechanical properties of the superficial layer of CNx coating such as hardness and Young's modulus have not been experimentally shown because of its small thickness estimated to be 10 nm or less. So we carried out in-depth measurements of mechanical properties of the thin layer on CNx film by nanoscratching test using an atomic force microscope. Then the existence of thin, soft layer on the top of CNx coating after running-in process was experimentally shown.

DOI： 10.1299/kikaic.76.3794

CO2 Laser Ablation Area Scaling And Redeposition On Flat Polyoxymethylene Targets Reviewed

John E. Sinko, Stefan Scharring, Yosuke Tsukiyama, Katsuhiro Ichihashi, Naoya Ogita, Akihiro Sasoh, Noritsugu Umehara, Hans-Albert Eckel, Hans-Peter Roeser

INTERNATIONAL SYMPOSIUM ON HIGH POWER LASER ABLATION 2010 1278 538 - + 2010

Language：English Publishing type：Research paper (international conference proceedings) Publisher：AMER INST PHYSICS

One of the remaining unknown subjects of laser propulsion involves whether special benefits or challenges exist for applying laser ablation propulsion to targets with particularly large or small spot areas. This subject is of high importance for a wide range of topics ranging from laser removal of space debris to micropropulsion for laser propulsion vehicles. Analysis is complex since different ablation phenomena are dominant between atmosphere and vacuum conditions. Progress has also been impeded by the difficulty of setting control parameters (particularly fluence) constant while the spot area is adjusted. It is also usually difficult for one group to address small- and large-area effects using a single high-power laser system. Recent collaborative experiments on laser ablation area scaling at several institutions, using 100-J class and 10-J class CO2 lasers, have advanced the understanding of laser propulsion area scaling. The spot area-dependence of laser propulsion parameters has been investigated over an area range covering approximately 0.05-50 cm(2) at low fluence of about 0.6 J/cm(2). The experiments were conducted well below the threshold for plasma formation, and provide an estimate of the ablation threshold for CO2 laser ablation of POM.

T1602-2-4 Measurement of Shearing Stress of the Topmost Layer of Carbon Nitride Coating by AFM

TSUKIYAMA Yosuke, KIMURA Norihiro, TOKOROYAMA Takayuki, UMEHARA Noritsugu

The proceedings of the JSME annual meeting 2010 231 - 232 2010

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Carbon nitride (CNx) coating is one of the carbonaceous materials, which was reported to show superlow friction coefficient (μ<0.009) in Nitrogen environment. Therefore CNx coating is a promising material of solid lubricant for sliding interfaces to reduce friction. The superlow friction appeared after running in process of several hundreds of friction cycles and its mechanism has not been completely clarified yet. It was proposed that the soft thin layer generated on CNx coating after running-in process contributed to the superlow friction. However, the shearing strength of the superficial layer of CNx coating has not been experimentally shown because of its small thickness estimated to be 10 nm or less. So we carried out in-depth measurements of the friction force of CNx film against a cantilever tip by nanoscratching test using an atomic force microscope. Then the existence of thin, low-shear layer on the top of CNx coating after running-in process was experimentally shown.

DOI： 10.1299/jsmemecjo.2010.8.0_231

Strength at the Interface of CNT Films Made by Surface Decomposition of SiC（共著） Reviewed

Yosuke Tsukiyama, Noritsugu Umehara, Michiko Kusunoki

Tribology Online 3 ( 7 ) 352 - 355 2008.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Tribologists

Adherence of carbon nanotube film made by surface decomposition of SiC was studied. For this purpose we carried out scratch tests in nano- and microscale. By microscratch test, it was found that adherence at the interface was higher for CNT films with shorter CNTs and CNTs were not broken at the middle but removed from the interface. To clarify the dominant force (shear force or moment of force) which caused different adherence, we also carried out nanoscratch test by using AFM. In nanoscratch, AFM tip made of diamond coated silicon applied shear force to CNT films from lateral direction. And there was no significant change of adherence by lateral force (shear force at the interface). We conclude that bending-induced moment of force is dominant on the interface strength of CNT films.

DOI： 10.2474/trol.3.352

Precision blanking of thin sheet metals with the help of chemical etching Reviewed

K. Hirota, Y. Tsukiyama, T. Yasuumi

JOURNAL OF MATERIALS PROCESSING TECHNOLOGY 201 ( 1-3 ) 209 - 213 2008.5

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE SA

It is difficult to separate small parts precisely from thin sheet metals by press blanking. This study describes a countermeasure to the problem by combining press forming and chemical etching. A 0.1 mm beryllium copper sheet was indented along a cut profile and subjected to etching, resulting in separation of the part surrounded by the indented line. Etching time to complete separation was considerably reduced compared with the ordinary etching process. Shape of indented portion also affected the etching time. Two indenting methods were tested in combination with two masking methods. SEM observation showed that every test condition provided a good cut edge having a smooth and fracture-free surface although some thickness reduction or dissolution of the cut edge occurred depending on masking methods. (C) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jmatprotec.2007.11.135

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