Experimental Study on Frictional Force and Wear Life of Oilless Sintered-Metal Bearings for the Reliability of the Geared Motor

2006 ◽  
Vol 326-328 ◽  
pp. 585-588
Author(s):  
Se Doo Oh ◽  
Yun Ha Shin ◽  
Young Ze Lee
Keyword(s):  
Electron Microscopy ◽  
Journal Bearing ◽  
The Other ◽  
Metal Powders ◽  
Sintered Metal ◽  
Wear Life ◽  
Before And After ◽  
Oil Flow ◽  
Frictional Forces ◽  
Scanning Electron

Oilless bearings, which are made with metal powders and then impregnated by oils, are widely used in rotating components. The friction coefficients and the oil loss rates of two types of oil-impregnated sintered-metal bearings (porous bearings, oilless bearings, or oilless metals) with varying loads were measured. One is the Cu-based bearing and the other is Fe-based bearing. The frictional forces of the bearings were measured using the journal bearing tester. By measuring the change of weight before and after sliding tests, the oil losses of oilless bearings were surveyed. Also, PV curves, which could be used to predict the life of the oilless bearing, were plotted. By observing the roundness, the cylindericity and the images of scanning electron microscopy of bearings before and after sliding tests, the tribological characteristics of the bearings were evaluated. It was found that Fe-based bearing show lower friction, more oil flow, less wear and longer life than Cu-based bearing.

Tribological Performance of Two Oilless Sintered-Metal Bearings for the Geared Motor in a Refrigerator

2006 ◽  
Vol 321-323 ◽  
pp. 1552-1555
Author(s):  
Se Doo Oh ◽  
Young Ze Lee
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Tribological Performance ◽  
The Other ◽  
Tribological Characteristics ◽  
Sintered Metal ◽  
Before And After ◽  
Frictional Forces ◽  
Scanning Electron

The tribological performances of two types of oilless sintered-metal bearings with varying loads were investigated. One is the Cu-based bearing and the other is Fe-based bearing. The frictional forces of the bearings were measured using the bearing tester. By measuring the change of weight before and after sliding tests, the oil losses of the bearings were surveyed. Also, PV curves, which could be used to predict the life of the oilless bearing, were plotted. By observing the roundness, the cylindericity and the images of scanning electron microscopy of bearings before and after sliding tests, the tribological characteristics of the bearings were evaluated. It was found that Fe-based bearing show lower friction, more oil loss, less wear and longer life than Cu-based bearing.

scholarly journals Redox Mechanism of Azathioprine and Its Interaction with DNA

2021 ◽  
Vol 22 (13) ◽  
pp. 6805
Author(s):  
Mihaela-Cristina Bunea ◽  
Victor-Constantin Diculescu ◽  
Monica Enculescu ◽  
Horia Iovu ◽  
Teodor Adrian Enache
Keyword(s):  
Electron Microscopy ◽  
Mass Spectrometry ◽  
Scanning Electron Microscopy ◽  
Structural Changes ◽  
Differential Pulse ◽  
Immunosuppressive Drug ◽  
Redox Mechanism ◽  
Before And After ◽  
Dna Film ◽  
Scanning Electron

The electrochemical behavior and the interaction of the immunosuppressive drug azathioprine (AZA) with deoxyribonucleic acid (DNA) were investigated using voltammetric techniques, mass spectrometry (MS), and scanning electron microscopy (SEM). The redox mechanism of AZA on glassy carbon (GC) was investigated using cyclic and differential pulse (DP) voltammetry. It was proven that the electroactive center of AZA is the nitro group and its reduction mechanism is a diffusion-controlled process, which occurs in consecutive steps with formation of electroactive products and involves the transfer of electrons and protons. A redox mechanism was proposed and the interaction of AZA with DNA was also investigated. Morphological characterization of the DNA film on the electrode surface before and after interaction with AZA was performed using scanning electron microscopy. An electrochemical DNA biosensor was employed to study the interactions between AZA and DNA with different concentrations, incubation times, and applied potential values. It was shown that the reduction of AZA molecules bound to the DNA layer induces structural changes of the DNA double strands and oxidative damage, which were recognized through the occurrence of the 8-oxo-deoxyguanosine oxidation peak. Mass spectrometry investigation of the DNA film before and after interaction with AZA also demonstrated the formation of AZA adducts with purine bases.

Use of electron microscopy to characterize the surfaces of flocculent and nonflocculent yeast cells

1989 ◽  
Vol 35 (12) ◽  
pp. 1081-1086 ◽  
Author(s):  
Byron F. Johnson ◽  
L. C. Sowden ◽  
Teena Walker ◽  
Bong Y. Yoo ◽  
Gode B. Calleja
Keyword(s):  
Electron Microscopy ◽  
Fission Yeast ◽  
Budding Yeast ◽  
The Other ◽  
Yeast Cells ◽  
Scanning Electron Micrographs ◽  
Soft Or ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Scanning Electron

The surfaces of flocculent and nonflocculent yeast cells have been examined by electron microscopy. Nonextractive preparative procedures for scanning electron microscopy allow comparison in which sharp or softened images of surface details (scars, etc.) are the criteria for relative abundance of flocculum material. Asexually flocculent budding-yeast cells cannot be distinguished from nonflocculent budding-yeast cells in scanning electron micrographs because the scar details of both are well resolved, being hard and sharp. On the other hand, flocculent fission-yeast cells are readily distinguished from nonflocculent cells because fission scars are mostly soft or obscured on flocculent cells, but sharp on nonflocculent cells. Sexually and asexually flocculent fission-yeast cells cannot be distinguished from one another as both are heavily clad in "mucilaginous" or "hairy" coverings. Examination of lightly extracted and heavily extracted flocculent fission-yeast cells by transmission electron microscopy provides micrographs consistent with the scanning electron micrographs.Key words: flocculation, budding yeast, fission yeast, scanning, transmission.

scholarly journals Effect of Surfactant Addition on Bi2Te3 Nanostructures Synthesized by Hydrothermal Method

2017 ◽  
Vol 62 (2) ◽  
pp. 1005-1010 ◽  
Author(s):  
Peyala Dharmaiah ◽  
C.H. Lee ◽  
B. Madavali ◽  
Soon-Jik Hong
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Method ◽  
Figure Of Merit ◽  
Bulk Sample ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coarse Grains ◽  
Scanning Electron ◽  
Nanostructured Sample

AbstractIn the present work, we have prepared Bi2Te3nanostructures with different morphologies such as nano-spherical, nanoplates and nanoflakes obtained using various surfactant additions (EG, PVP, and EDTA) by a hydrothermal method. The shape of the nanoparticles can be controlled by addition of surfactants. The samples were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). It is found that the minority BiOCl phase disappears after maintained pH at 10 with EG as surfactant. SEM bulk microstructure reveals that the sample consists of fine and coarse grains. Temperature dependence of thermoelectric properties of the nanostructured bulk sample was investigated in the range of 300-450K. The presence of nanograins in the bulk sample exhibits a reduction of thermal conductivity and less effect on electrical conductivity. As a result, a figure of merit of the sintered bulk sample reached 0.2 at 400 K. A maximum micro Vickers hardness of 102 Hv was obtained for the nanostructured sample, which was higher than the other reported results.

Synthesis and Film Investigation of Titania

2013 ◽  
Vol 832 ◽  
pp. 128-131
Author(s):  
Sharipah Nadzirah ◽  
Uda Hashim
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Thin Films ◽  
Scanning Electron Microscopy ◽  
Titanium Dioxide ◽  
Sol Gel ◽  
Titanium Butoxide ◽  
Before And After ◽  
Scanning Electron ◽  
Spin Coater

Titania or titanium dioxide (TiO2) thin film has been synthesized via sol-gel method with monoethanolamine (MEA) as a catalyst. The mixing of titanium butoxide as a precursor, ethanol as a solvent and MEA were stirred using magnetic stirrer under ambient temperature [. The TiO2solution prepared then was deposited on SiO2substrates using spin-coater and the coated films were annealed at 600°C. Finally, both before and after annealed TiO2thin films were characterized using Field Emission Scanning Electron Microscopy (FESEM). The obtained results show the different TiO2particles formation before and after annealed.

Problems associated with ageing squid from their statoliths: towards a more structured approach

1994 ◽  
Vol 6 (2) ◽  
pp. 215-222 ◽  
Author(s):  
Marek R. Lipinski ◽  
M. Deon Durholtz
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Regression Analysis ◽  
Light Microscopy ◽  
The Other ◽  
Etching Solution ◽  
Significant Difference ◽  
Structured Approach ◽  
Fish Otoliths ◽  
Scanning Electron

It appears that squid statoliths cannot yet be regarded as accurate an ageing tool as fish otoliths. Statoliths from the same pair, prepared differently for viewing and counting increments, were compared. Increment counts do not imply age in days, because this was not validated. One statolith from each pair was examined by light microscopy (LM) after preparation following a new method. The other was viewed by Scanning Electron microscopy (SEM) with a modified etching solution. Shape of each statolith was similar when compared by multiple regression analysis (11 variables, n=53). There was a weak but significant difference between sexes (statoliths of females were slightly larger). All other differences were insignificant. Microscopic observation and increment counts of increments were successfully carried out for 37 pairs of statoliths. Significant differences between two independent counts were found for the LM method, but no significant differences were found between two independent SEM counts. Counts were significantly different when interpreted by both LM and SEM, probably because of poor resolution in the LM readings and over-resolution (growth layers prominent and numerous) in those read by SEM. Recommendations are made on how ageing studies, based on statoliths, should be structured and the results evaluated.

Pollen morphology of Sabinaria magnifica (Cryosophileae, Coryphoideae, Arecaceae)

Phytotaxa ◽  
2015 ◽  
Vol 207 (1) ◽  
pp. 135 ◽  
Author(s):  
Giovanni Raul Bogota ◽  
Carina Hoorn ◽  
Wim Star ◽  
Rob Langelaan ◽  
Hannah Banks ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Light Microscopy ◽  
Pollen Morphology ◽  
Pollen Grains ◽  
The Other ◽  
Transmission Electron ◽  
Palm Species ◽  
Scanning Electron

Sabinaria magnifica is so far the only known species in the recently discovered tropical palm genus Sabinaria (Arecaceae). Here we present a complete description of the pollen morphology of this palm species based on light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). We also made SEM-based comparisons of Sabinaria with other genera within the tribe Cryosophileae. Pollen grains of Sabinaria magnifica resemble the other genera in the heteropolar, slightly asymmetric monads, and the monosulcate and tectate exine with perforate surface. Nevertheless, there are some clear differences with Thrinax, Chelyocarpus and Cryosophila in terms of aperture and exine. S. magnifica differs from its closest relative, Itaya amicorum, in the exine structure. This study shows that a combination of microscope techniques is essential for the identification of different genera within the Cryosophileae and may also be a necessary when working with other palynologically less distinct palm genera. 

Inclined Substrate Deposition by Evaporation of Magnesium Oxide for Coated Conductors

1999 ◽  
Vol 585 ◽  
Author(s):  
Markus Bauer ◽  
Ralf Metzger ◽  
Robert Semerad ◽  
Paul Berberich ◽  
Helmut Kinder
Keyword(s):  
Electron Microscopy ◽  
Coated Conductors ◽  
The Other ◽  
Buffer Layers ◽  
Columnar Growth ◽  
Initial Momentum ◽  
3D Monte Carlo ◽  
Deposition Direction ◽  
Angle Deposition ◽  
Scanning Electron

AbstractBiaxially textured MgO buffer layers were deposited on metal substrates using “inclined substrate deposition” (ISD). The influence of the substrate inclination angle, deposition rate, and film thickness on the texture is shown. Scanning electron microscopy reveals columnar growth. We developed a growth model to explain the texturing. To test this model we have carried out 3D Monte-Carlo simulations. We find that the preferred orientation arises from mutual shadowing of the columns and directional surface diffusion due to their initial momentum.YBa2Cu3O7 (YBCO) films deposited on the ISD buffer layers are highly textured. The ab-planes of the YBCO are tilted with respect to the surface by typically 25° towards the direction of MgO vapor incidence. Therefore, the critical current density jc is anisotropic with up to 8 × 105 MA/cm2 in one direction and 4 × 105 MA/cm2 in the other. For tape coating the MgO deposition direction can be chosen so that the high jc is along the tape.

Application of UV Irradiation in Removal of Post-etch 193 nm Photoresist

2009 ◽  
Vol 1156 ◽  
Author(s):  
Quoc Toan Le ◽  
Els Kesters ◽  
L Prager ◽  
Marcel Lux ◽  
P Marsik ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Uv Irradiation ◽  
Bond Cleavage ◽  
Chemical Change ◽  
The Other ◽  
Cleaning Efficiency ◽  
Thickness Change ◽  
Methyl Pyrrolidone ◽  
193 Nm ◽  
Scanning Electron

AbstractThis study focused on the effect of UV irradiation on modification of polymethyl methacrylate-based photoresist, and then on wet photoresist (PR) removal of patterned structure (single damascene structure). Three single-wavelength UV sources were considered for PR treatment, with λ = 172, 222, and 283 nm. Modification of blanket PR was characterized using Fourier-transform infrared spectroscopy (FTIR; chemical change), spectroscopic ellipsometry (SE; thickness change), and dissolution in organic solvent (solubility change). While for patterned samples, scanning electron microscopy (SEM) was used for evaluation of cleaning efficiency. In comparison to 172 nm, the PR film irradiated by 222 nm and 283 nm photons resulted in formation of higher concentration in C=C bond. Immersion tests using pure N-methyl pyrrolidone (NMP) at 60 °C for 2 min showed that some improvement in PR removal was only observed for PR films treated by 283 nm UV for short irradiation times. Irradiation by photons at the other two wavelengths did not result in an enhancement of removal efficiency.The PR film treated by 222 nm photons was chosen for further study with O3/H2O vapor at 90°C. Experimental results showed a complete PR and BARC removal for UV-treated PR, which can be explained by C=C bond cleavage by the oxidizer.

Some possibilities of representing microcirculation in human spleen

Biologia ◽  
2009 ◽  
Vol 64 (6) ◽  
Author(s):  
Paulína Gálfiová ◽  
Ivan Varga ◽  
Martin Kopáni ◽  
Peter Michalka ◽  
Jana Michalková ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Confocal Microscopy ◽  
The Other ◽  
Corrosion Casts ◽  
Histochemical Analysis ◽  
Human Spleen ◽  
Scanning Confocal Microscopy ◽  
Scanning Electron

AbstractThe representation of microcirculation can be approached in several ways. One of the possibilities is to represent the endothelium (endothelial or sinus lining cells) and their basement membrane on the basis of detecting the known components and the expression of the surface antigenes by the methods of immuno-, enzyme- or lectino-histochemical analysis, or by staining or impregnation histological methods. The other possibility is the examination of samples by transmission and scanning electron microscopy. For three-dimensional demonstration corrosion casts techniques or laser scanning confocal microscopy can be used. In this paper we describe the survey of immuno-, enzyme- and lectino-histochemical characteristics of selected components of microcirculation and our own results of its demonstration in human spleen.

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