scholarly journals Effect of Square Texture on Tribological Properties of Nano-SiO2/POB-PTFE Composites

2022 ◽  
Vol 2160 (1) ◽  
pp. 012013
Author(s):  
Dongya Yang ◽  
Wei Xue ◽  
Xinwen Xiong ◽  
Weitao Li ◽  
Rongtuo Sun ◽  
...  
Keyword(s):  
Contact Surface ◽  
Optical Microscope ◽  
Transfer Film ◽  
Stirling Engine ◽  
In Situ Observation ◽  
Laser Marking ◽  
Seal Design ◽  
Observation Methods ◽  
Smooth Contact ◽  
Ptfe Composites

Abstract In order to study the seal design problem of piston rings in Stirling engine, on the basis of filling PTFE with Nano-SiO2 and POB and preparing the GCr15 contact surface with square texture by HM20-I laser marking machine, experiments were carried out on LSR-2M wear tester by indirect weighing and in-situ observation methods. Optical microscope (OM) and scanning electron microscope (SEM) were used to observe the evolution of Nano-SiO2/POB-PTFE composites’ transfer film on contact surface. The results showed that the square texture would shorten the running-in and transitionary periods of the composites’ tribological process, accelerate into the stationary period. The formation process of the composites’ transfer film on the square textured contact surface was also different from smooth contact surface. Although the square texture would increase wear rate, its ability to store wear debris is more conducive to the formation of reliable, uniform and continuous transfer film with a same friction direction. Obviously, reasonable design of surface texture can effectively improve the wear resistance of sealing parts made of filling modified PTFE composites, thus providing theoretical guidance for the seal design of Stirling engine piston ring.

scholarly journals In-situ observation of graphene using an optical microscope

2021 ◽  
Vol 6 ◽  
pp. 100138
Author(s):  
Mikihiro Kato ◽  
Sujun Guan ◽  
Xinwei Zhao
Keyword(s):  
Optical Microscope ◽  
In Situ Observation

Tribological Properties of Polyoxymethylene Composites Against Aluminum

2003 ◽  
Vol 125 (3) ◽  
pp. 661-669 ◽  
Author(s):  
Masaya Kurokawa ◽  
Yoshitaka Uchiyama ◽  
Tomoaki Iwai ◽  
Susumu Nagai
Keyword(s):  
Wear Rate ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
High Surface ◽  
Surface Hardness ◽  
Disk Surface ◽  
Optical Microscope ◽  
Transfer Film ◽  
The Other ◽  
The Coefficient Of Friction

Tribological properties of several kinds of polyoxymethylene (POM) composites were evaluated for the purpose of developing a polymeric tribomaterial especially suited for mating with aluminum parts having low surface hardness. POM composites containing small amounts of silicon carbide (SiC), POM/SiC; those containing a small amount of calcium octacosanonoate besides SiC, POM/SiC/Ca-OCA; and the one blended with 24 wt % of polytetrafluoroethylene, POM/PTFE(24); were injection-molded into pin specimens and their tribological properties were tested by means of a pin-on-disk type wear apparatus using an aluminum (A5056) mating disk in comparison with a 303 stainless steel (SUS303) disk. Evaluation was focused on observation of the sliding surfaces of the pin specimens and the mating disks by a scanning electron microscope and an optical microscope together with the measurement of surface roughness. In the case of mating against a SUS303 disk having high surface hardness, all pin specimens did not roughen the disk surfaces even after long time of rubbing. Only POM/PTFE(24) composite obviously made a transfer film on the disk surface, while the other composites made an extremely thin one on it. POM/SiC(0.1)/Ca-OCA(1) composite, containing SiC 0.1 wt. % and Ca-OCA 1 wt. %, was found to show the lowest coefficient of friction and the lowest wear rate forming extremely thin transfer film on the mating disk. On the other hand, against an A5056 disk which has lower surface hardness than that of SUS303 disk, unfilled POM and POM composites except POM/SiC(0.1)/Ca-OCA(1) composite roughened the disk surfaces. However, the sliding surface of the A5056 disk rubbed with POM/SiC(0.1)/Ca-OCA(1) composite was significantly smoother and that of the pin specimen was also quite smooth in comparison with other pin specimens. Further, when each POM composite was rubbed against the A5056 disk, formation of transfer film was not obvious on the disk surfaces. For POM/SiC(0.1)/Ca-OCA(1) composite, the wear rate was the lowest of all POM composites, and the coefficient of friction was as low level as 60 percent of that of unfilled POM, but slightly higher than that of POM/PTFE(24) composite. For POM/SiC(0.1)/Ca-OCA(1) composite, the nucleating effect of SiC and Ca-OCA, which accelerated the crystallization of POM during its injection molding to form a matrix containing fine spherulites, must have resulted in increasing the toughness of the matrix and lowering the wear rate. Also, the lubricant effect of Ca-OCA should have lowered the coefficient of friction of the same matrix for rubbing against aluminum mating disk. POM/SiC(0.1)/Ca-OCA(1) composite was concluded as an excellent tribomaterial for mating with aluminum parts.

Characteristics of the Transfer Film and Tribological Properties of Oxide/PTFE Composites

2013 ◽  
Vol 631-632 ◽  
pp. 172-175 ◽  
Author(s):  
Ting Xie ◽  
Zheng Hua Zhou ◽  
Zhen Xing Xu ◽  
Jian Wei Yu ◽  
Ming Hua Jiao
Keyword(s):  
Adhesion Strength ◽  
Tribological Properties ◽  
Interfacial Adhesion ◽  
Measured Data ◽  
Transfer Film ◽  
Micro Hardness ◽  
Transfer Films ◽  
Ptfe Composites ◽  
Interfacial Adhesion Strength ◽  
Better Than

The formed transfer film on the counterpart surface and tribological properties of PTFE composites filled with Al2O3 or SiO2 were investigated in this paper. The results indicated that under the same friction conditions, the friction coefficients of SiO2/PTFE and Al2O3/PTFE are very close to each other, but the wear resistance of SiO2/PTFE is superior to that of Al2O3/PTFE. According to the measured data, the micro-hardness and elastic modulus of the transfer film for SiO2/PTFE are much better than those of Al2O3/PTFE. In addition, the interfacial adhesion strength between the transfer film of SiO2/PTFE and the counterface is higher. It can be proved that the mechanical properties of transfer films for PTFE composites vary with different fillers and the friction transfer film with better adhesion strength and mechanical property is useful to improve the tribological properties of the composite.

Investigation of Laser Marking Technology with the Image Mask of Liquid Crystal Display

2010 ◽  
Vol 43 ◽  
pp. 633-636 ◽  
Author(s):  
Fei Chen ◽  
Zhao Yang Zhang ◽  
Yao Min Wang
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystal Display ◽  
Optical Microscope ◽  
Light Transmittance ◽  
Light Modulation ◽  
Laser Marking ◽  
Modulation Function ◽  
Nanosecond Pulsed Laser ◽  
Process System ◽  
Image Mask

In the laser marking process system, a liquid crystal display (LCD) was used as the image mask, which can display dynamically and flexibly the various images by the programmable control. A nanosecond pulsed laser (1064nm) was applied to investigate the characteristic of laser photolithography fabrication technology. The light modulation function of LCD mask was firstly discussed by theory. By observing the graphics morphology with a high-powered optical microscope, it was found that the graphics of laser marking with LCD mask shows that its edges were not ablated but its line inside was ablated. According to analysis, the reasons of this phenomenon are due to the opaque lattice effect and the high light transmittance of black pixel. Results showed that the light modulation function of LCD mask was decided by adjusting the light transmittance with controlling the pixel voltage and a complete graphics was ablated in the range of 0.6J/cm2 ~ 0.8J/cm2.

scholarly journals Enhancing In Situ Observation with the SCI Design (Shadowing–Conversations–Interview to the Double) to Capture the Cognitive Underpinnings of Action

M n gement ◽  
2020 ◽  
Vol 23 (3) ◽  
pp. 28-44
Author(s):  
Christelle Théron
Keyword(s):  
In Situ Observation ◽  
Situated Action ◽  
Observation Methods ◽  
Double Technique

In situ observation methods have essentially been mobilized to study actors’ doings, but they have also been mobilized (through studies in the stream of situated action) to study cognition in these same organizational actors. The existing methodological designs have helped to enhance our knowledge of certain cognitive underpinnings, but they carry two limits: (1) they are deployed following a stacking logic, that is, by triangulation, which is more about compensating for the weaknesses of the component methods than uniting their strengths, and which has the pitfall of capturing cognition and action separately; and (2) they cannot capture all the situated and structuring facets of the cognitive underpinnings of action. Here we propose to overcome these barriers with the SCI design: S for shadowing, C for conversions, and I for an interview borrowing on the ‘interview to the double’ technique. This design is built in a synergy-guided effort that hinges on tightly meshing these three techniques together at fieldwork deployment. This articulation makes it possible to capture action and cognition together and to surface both the situated and structuring facets of cognition underpinning action. The SCI design is easy enough to deploy in fieldwork across a whole range of research settings.

Microscopic Observations of SOFC Anodes Under Operation With Hydrocarbon Fuels

2004 ◽  
Author(s):  
Tatsuya Kawada ◽  
Keiji Yashiro ◽  
Tomoaki Taura ◽  
Kenichiro Takeda ◽  
Atsushi Kaimai ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Carbon Deposition ◽  
Optical Microscope ◽  
Open Circuit ◽  
In Situ Observation ◽  
Nickel Surface ◽  
Operation Condition ◽  
Grid Electrode ◽  
Laser Raman

Carbon deposition on a SOFC anode was investigated under direct hydrocarbon fueling condition. Microscopic behaviors were observed with a newly designed sample holder that enabled in-situ observation of an electrode in operation under controlled atmosphere at elevated temperatures. The preferential carbon deposition site, the structure of the deposited carbon, and the chemical or electrochemical re-oxidation processes were investigated with an optical microscope combined with a laser Raman microscope. Color and morphology change of the electrode surface was recorded with a CCD camera, and the deposited materials were identified with a laser Raman microscope. A nickel micro grid was used as a model electrode of a well-defined microstructure. When the cell was kept at an open circuit condition in methane, carbon started to deposit on the surface of Ni grid electrode. The deposition of carbon was clearly observed as the change in the reflection on the nickel surface by optical microscope as well as by the appearance of the specific peak at ∼ 1560 cm−1 in Raman spectroscopy. The deposited carbon was in the form of graphite on the nickel grid electrode. The carbon coverage on the surface was not uniform but varied from grain to grain. When a certain anodic overpotential (e.g. 200 mV) was applied to the electrode, the carbon disappeared gradually from the edge of the electrode i.e. from the electrode/electrolyte boundary where oxygen was supplied electrochemically. It is the first in-situ observation of the electrochemical carbon oxidation in a real operation condition.

Adhesive Gripping Elements in a Construction of Gripping Heads

2015 ◽  
Vol 772 ◽  
pp. 339-343
Author(s):  
Marcel Horák ◽  
František Novotný
Keyword(s):  
Contact Surface ◽  
Carrying Capacity ◽  
Smooth Contact ◽  
Contact Surfaces ◽  
Plastic Products

The paper describes possibilities to use industrially adhesive gripping elements in automatized handling processes especially for flat objects but also for objects slightly dissected according to height (e.g. sheets of glass, plastics, metals, plastic products etc.) which have dry, relatively clean, and smooth contact surfaces. It begins by analyzing results obtained in the field of designing combined vacuum-adhesive gripping elements, and the exclusively adhesive (passive) ones being suitable for technologically difficult handling conditions, e.g. in vacuum, as well. Furthermore, problems of the maximum carrying capacity of individual gripping elements being arranged parallel on a frame of a multi-element gripping head. A new concept of a compensation module of the gripping element position is presented as well, namely in relation to the head frame and to the handling object contact surface dissected according to height.

scholarly journals Very Low Nucleation Rates of Glucose Isomerase Crystals under Microgravity in the International Space Station

Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 90
Author(s):  
Yoshihisa Suzuki ◽  
Takahisa Fujiwara ◽  
Katsuo Tsukamoto ◽  
Seijiro Fukuyama ◽  
Taro Shimaoka ◽  
...  
Keyword(s):  
International Space Station ◽  
Growth Rates ◽  
Space Station ◽  
Glucose Isomerase ◽  
Optical Microscope ◽  
In Situ Observation ◽  
International Space ◽  
High Supersaturation ◽  
Very High

In situ observation of the nucleation and growth of glucose isomerase (GI) crystals under microgravity was conducted using an optical microscope during the first flight of the Advanced Nano Step project undertaken in the International Space Station (ISS). Very low apparent nucleation rates (J’) of GI crystals in the solution and on the substrate of the growth container were confirmed compared with those on the ground. In particular, J’ of GI crystals in the solution were a few times lower than that on the substrate. The growth rates (R) of the {101} faces of GI crystals on the substrate and the apparent growth rates (R’) in the solution were measured. The very low nucleation rates allowed us to successfully measure R at a very high supersaturation region (up to ln(C/Ce) = 6), at which R cannot be measured on the ground.

3-D EBIC Technique using FIB and EB Double Beam System

2005 ◽  
Author(s):  
Eiji Yoshida ◽  
Tomohiro Tanaka ◽  
Taro Oyamada ◽  
Tohru Koyama ◽  
Junko Komori ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Three Dimensional ◽  
Optical Microscope ◽  
Laser Marking ◽  
Diffusion Structure ◽  
Double Beam ◽  
Marking Technique ◽  
Electron Beam Induced Current ◽  
A Site

Abstract We propose visualizing techniques of a diffusion layer using an electron beam induced current (EBIC) for a site-specific cross-section formed by focused ion beam (FIB) treatment. Moreover, we present a three-dimensional (3-D) EBIC technique using a double beam (FIB & EB) system to understand the diffusion structure. This 3-D application of the EBIC technique is very useful for delineating PN junctions and pointing out implant defects in ULSI devices. Furthermore, we applied the EBIC technique to backside circuit editing with FIB. The end-point of the silicon trench etching can be easily decided by observing the plane EBIC images. Highly reliable backside circuit editing becomes possible together with a DUV laser marking technique using an IR-optical microscope system.

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