scholarly journals Microstructural Analysis of Wool Fibers by SEM Images of Their Cross-Sections Etched by Alkali Treatment

2009 ◽  
Vol 65 (9) ◽  
pp. 246-251 ◽  
Author(s):  
Michiko Okada ◽  
Yoshiharu Kimura ◽  
Kyohei Joko
2017 ◽  
Vol 51 ◽  
pp. 274-280
Author(s):  
A. D. Potemkin ◽  
Yu. S. Mamontov ◽  
N. S. Gamova

Study of selected specimens of Gymnomitrion collected by D. G. Long in Yunnan, China, revealed a new species, G. fissum Mamontov et Potemkin, sp. nov., with a fissured leaf surface. Comparison of SEM images of the leaf surface and leaf cross sections shows that the leaf surface of G. fissum is different from that of other known species with a superficially similar leaf surface, i. e. Mylia taylorii, M. verrucosa s. l. and Trabacellula tumidula. It has fissures around the cell lumen rather than grids and perforations. Outer cell walls of Gymnomitrion fissum are much thicker than in Mylia taylorii, M. verrucosa s. l. and Trabacellula tumidula, and their outer layers tend to be partly or completely caducous. G. fissum is related to the group of species assigned to the former genus Apomarsupella.


Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2523
Author(s):  
Franciszek Pawlak ◽  
Miguel Aldas ◽  
Francisco Parres ◽  
Juan López-Martínez ◽  
Marina Patricia Arrieta

Poly(lactic acid) (PLA) was plasticized with maleinized linseed oil (MLO) and further reinforced with sheep wool fibers recovered from the dairy industry. The wool fibers were firstly functionalized with 1 and 2.5 phr of tris(2-methoxyethoxy)(vinyl) (TVS) silane coupling agent and were further used in 1, 5, and 10 phr to reinforce the PLA/MLO matrix. Then, the composite materials were processed by extrusion, followed by injection-molding processes. The mechanical, thermal, microstructural, and surface properties were assessed. While the addition of untreated wool fibers to the plasticized PLA/MLO matrix caused a general decrease in the mechanical properties, the TVS treatment was able to slightly compensate for such mechanical losses. Additionally, a shift in cold crystallization and a decrease in the degree of crystallization were observed due to the fiber silane modification. The microstructural analysis confirmed enhanced interaction between silane-modified fibers and the polymeric matrix. The inclusion of the fiber into the PLA/MLO matrix made the obtained material more hydrophobic, while the yellowish color of the material increased with the fiber content.


1997 ◽  
Vol 480 ◽  
Author(s):  
Helen L. Humiston

AbstractThe complex materials systems in VLSI devices require specialized preparation techniques for TEM microstructural analysis. For this purpose, it is desirable to obtain electron transparency in all material layers from the oxides used in dielectrics to refractory metals such as tungsten. The primary advantage of dimpling these materials is that ideal specimens are obtained for low angle ion milling. By dimpling both sides of the cross section with a padded flatting tool, a thicker specimen of 130μm at the outer rim of the 3mm disc is produced that narrows to the 125nm thickness fringes in the center. These samples do not require a copper support grid, thereby allowing for a lower milling angle of 2.5 degrees on both sides of the specimen. This technique provides a cross section that is electron transparent in all layers without the loss of oxides due to differential thinning rates of various materials at higher milling angles.It is generally thought that precision thinning through a submicron feature is not possible on the dimpler. However, a simple step-by-step procedure for this technique will be demonstrated and discussed.


2000 ◽  
Vol 8 (2) ◽  
pp. 36-39
Author(s):  
Clive Chandler

Control of layer thickness is critically important in the manufacture of semiconductor devices. Cross-sectioning exposes device structures for direct examination but conventional sample preparation procedures are difficult, time consuming, and grossly destructive. Cross sections created by focused ion beam (FIB) milling are easier, faster, and less destructive but have not offered the clear layer delineation provided by etching in the conventional sample preparation process. A new gas etch capability (Delineation Etch™ from FEI Company) offers results that are equivalent to conventional wet-etch preparations in a fraction of the time from a single, automated system in the fab without destroying the wafer. The new etch process also has application in milling high-aspect-ratio holes to create contacts to buried metal layers, and in deprocessing devices to reveal silicon and polysilicon structures.


2018 ◽  
Vol 778 ◽  
pp. 28-32
Author(s):  
Muhammad Shahzad ◽  
Tanveer Manzoor ◽  
Qanita Tayyaba ◽  
Ammad Hussain Qureshi

Presented results report the findings of a case study carried out to determine the possible factors that lead to the twisting of tail rotor shaft. The structural materials of the shaft was evaluated in terms of microstructural analysis and mechanical properties to rule out any material fault. The SEM images showed that the localized fractures at twist ends occurred without any significant plastic deformation. Moreover, there was no evidence of fatigue. Such behavior suggests that twist occurred under impact / high strain rate loading. Such loading conditions are not possible during the event to ground hitting. The Ansys simulation confirmed that the observed twisting can increase the stress at localized point in excess of UTS and cause fracture.


2019 ◽  
Vol 13 (3) ◽  
pp. 234-240
Author(s):  
Elnaz Moslehifard ◽  
Mahmood Robati Anaraki ◽  
Saeed Shirkavand

Background. The current study evaluated the compressive, flexural and impact strengths of heat-cured acrylic resins reinforced by TiO2 nanoparticles (NPs). Methods. TiO2 NPs were provided and characterized using scanning electron microscopy (SEM) to determine their morphology and crystalline structure. For three mechanical tests, 12 acrylic resin groups (n=9), totaling 108 specimens, were prepared using a special mold for each test, with TiO2 nanoparticle contents of 0, 0.5, 1 or 2 wt% in different groups. After curing, the compressive, flexural and impact strengths of the specimens were examined according to ISO 1567. Results. In the SEM and XRD study of TiO2 NPs, anatase was identified as the major crystalline phase followed by rutile (average particle size: 20.4 nm). SEM images showed that the nanocomposite with 1 wt% NPs had a more homogenized blend. 1 wt% TiO2 nanocomposite exhibited a higher, but non-significant, impact strength compared to the controls. ANOVA showed significant differences in the impact and flexural strengths between nanocomposites with various contents of TiO2 NPs. Conclusion. The nanocomposite with 1 wt% TiO2 NPs exhibited fewer micro-pores and micro-cracks in the SEM cross-sections. A non-significant increase was also observed in the impact strength with TiO2 NPs at 1 wt%. Further increase in TiO2 NPs decreased both the impact and flexural strengths. The compressive strength of the heat-cured acrylic resin was not affected by the incorporation of NPs.


2016 ◽  
Vol 61 (2) ◽  
pp. 1129-1134 ◽  
Author(s):  
J. Krawczyk

Abstract The microstructure of as-cast cored turbine blades roots, made of the single-crystal CMSX-4 nickel-based superalloy was investigated. Analysed blades were obtained by directional solidification technique in the industrial ALD Bridgman induction furnace. The investigations of the microstructure of blades roots were performed using SEM and X-ray techniques including diffraction topography with the use of Auleytner method. Characteristic shapes of dendrites with various arrangement were observed on the SEM images taken from the cross-sections, made transversely to the main blades axis. The differences in quality of the structure in particular areas of blades roots were revealed. Based on the results, the influence of cooling bores on blades root structure was analysed and the changes in the distribution and geometry of cooling bores were proposed.


2011 ◽  
Vol 332-334 ◽  
pp. 1077-1081
Author(s):  
Hong Ling Yi ◽  
Wei Shan Wang ◽  
Heng Lin ◽  
Wei Guang Gong ◽  
Ting Wei ◽  
...  

In this paper, a new type of LLDPE/nano CaCO3 composite based artificial turf yarns with good tensile property and UV resistance is introduced. The effect of nano CaCO3content on tensile properties shows that the tensile force reached the maximum value when the CaCO3 content is about 7wt%, and the elongation at break gets to the highest point at 10wt%. After 3000h UV accelerated aging, the nano-CaCO3 and LLDPE based artificial turf fiber yarns has tensile strength retention about 87%, and the elongation at break is higher than LLDPE. DSC results shows that with the increase of nano-CaCO3 content, the crystallization temperature gradually increased, and the crystallinity degree declined. SEM images of cross sections of monofilament fibers show that nano CaCO3 had a good dispersion in monofilament fiber matrix. These reasons give rise to the improved mechanical properties of turf yarns.


2017 ◽  
Vol 751 ◽  
pp. 563-569
Author(s):  
Oratai Jongprateep ◽  
Napamas Jaroonvechatam ◽  
Supicha Stienkijumpai ◽  
Sicha Kaewsuwan ◽  
Thanawat Meesak

High porosity in porous concretes contributes to benefits in terms of lightweight, high water permeability, and superior insulation properties in the concretes. Nevertheless, excessive porosity can lead to diminished compressive strength. This study, therefore, aimed at fabricating porous concretes with porosity and compressive strength in the range suitable for practical applications. Since addition of aluminium powder is a well-known technique for porosity production, this study also assessed effects of aluminium addition on properties of porous concretes. Relationships among concentrations of aluminium, porosity, and compressive strength of the specimens were examined. Microstructural analysis from scanning electron microscope (SEM) images and compressive strength testing according to ASTM C109 revealed that the specimens with 0.15 wt% Al demonstrated porosity and compressive strength were in an acceptable range. Additionally, porosity production and specimen strengthening were discussed with respect to chemical compositions.


2013 ◽  
Vol 49 (3) ◽  
pp. 271-277 ◽  
Author(s):  
A. Cosovic ◽  
V. Cosovic ◽  
T. Zák ◽  
B. David ◽  
N. Talijan

Nanosize NiFe2O4 was prepared by template method and precipitation process using same starting materials. The use of soluble starch in both synthesis routes was investigated. The amount of the used precipitating agent (Na2CO3) for the precipitation approach was selected according to two adopted scenarios based on theoretical and average yield of possible side reaction expressed by the degree of substitution (DS). The results of SEM microstructural analysis of the prepared Niferrite powders demonstrate evident influence of the applied preparation method whereas high-magnification FE-SEM images show very similar fine-grained structures characterized by different size of particles. According to the results of XRD analysis, the obtained ferrite powders exhibit only slight differences in phase composition with calculated crystallite size for template sample dXRD = 36 nm and for the both precipitation route samples dXRD = 21 nm. Additional sample characterization using 57Fe M?ssbauer spectroscopy supports the findings of the microstructural and XRD analysis. The ?clearest? spectrum was obtained for the template sample while the strongest influence of nanocrystalline component was observed for the sample prepared with maximal amount of precipitation agent (DS=3). The room temperature magnetic hysteresis loops, recorded using vibrating sample magnetometer (VSM), are very similar and exhibit characteristic shape with values of magnetic properties within expected range for this type of material.


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