Papers by Keyword: Microscopy

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Authors: George D. Quinn
Abstract: The evolution of the science of fractography of brittle materials initially was driven by failure analysis problems. Early analyses focused on general patterns of fracture and how they correlated to the loading conditions. Many early documents are simply descriptive, but the curiosity of some key scientists and engineers was aroused. Scientific or engineering explanations for the observed patterns gradually were developed. Advances in microscopy and flaw based theories of strength and fracture mechanics led to dramatic advances in the state of the art of fractographic analysis of brittle materials. Introduction: This author was drawn backwards in time as he researched the current state of the art of fractographic analysis of brittle materials for his fractography guide book.[ ] Others have written about how the fractographic analysis of metals evolved (e.g., [ , , , ]), but there is no analogue for ceramics and glasses. The key scientists, engineers, and analysts who contributed to our field are shown in Fig. 1. Other work done by industry workers who were unable or loathe to publish is now lost, inaccessible, forgotten, or even discarded. It is the goal of this paper to review the key publications and mark the noteworthy advances in the field. Some deem fractography as the study of fracture surfaces, but this author takes a broader view. Fractography is the means and methods for characterizing fractured specimens or components and, for example, a simple examination of the fragments and how they fit together to study the overall breakage pattern is a genuine fractographic analysis.
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Authors: Guo Liang Huang, Zhong Hua Dong, Cheng Deng, Shu Kuan Xu, Jiang Zhu, Xiao Yong Yang, Guo Fan Jin
Abstract: Microscopy is an important tool in biology and medicine, but it is often limited to optical imaging structures with high numerical aperture(NA) with a short working distance(wd), for example NA = 0.6 and wd <1 mm are usual. The common microscope objective is inadequate for imaging of living cells in culture as an optical imaging structure with both high numerical aperture and long working distance is required. In this study, a novel optical design has been developed to meet the long working distance and high resolution power imaging of living cells in a vessel with a high culture solution thickness, where cells need to be developed in about 48 hours or a week. The developed optical design was characterized by an ultra-long working distance (wd >13.5 mm) and high numerical aperture (NA = 0.7). This optical imaging system is not only good for the subcellular imaging of free-floating cells in culture, but also for the imaging of cells attached at a surface of vessel.
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Authors: Adrian Catalin Pavalache, Gabriel Marius Dumitru, Elena Manuela Stanciu, Raúl López, Mihai Vasile, Dan Petre
Abstract: The use of laser cladding (LC) technology for the improvement of surface properties in various mechanical design applications has given rise to the development of application-oriented composites. The present paper furnishes relevant notes on an experimental approach to the design optimization of experiments regarding WC-Co based layers obtained by laser cladding. The current paper emphasizes the influence of parameter variation on the characteristics of the deposited layer and reports the manner in which the heat input and the laser power density influence the microstructure.
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Authors: Ricardo Marques Barreiros, Simone Simões Amaral, Carlos Alberto Oliveira de Matos, Alex Siqueira Costa
Abstract: This work aims to contribute with information about the structural wood anatomical description Calophyllum brasiliense Camb.. The study was conducted in an area of 1350 m2, with spacing 4.0 m x 2.5 m, in the Paraná State, Brazil. Five specimens of C. brasiliense, with 13 years of age, were collected. For the macro and microscopic anatomical analyses were obtained disks to 0%, 25% and 50% of the commercial height of the trunk. The anatomical structure of wood of C. brasiliense, from pure plantation, was similar to existing literature for native forests. The results showed that the cultivation of trees of Guanandi, from pure plantation, can be a sustainable alternative in obtaining building material.
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Authors: Kamil Ďurana, Robert Černý
Abstract: Optical microscopy presents an extension of standard methods for pore space description. In this paper two examples of application in materials and mechanical engineering are introduced. The porosity and pore size distribution of two types of AAC are measured. In the second example the thermally induced cracks of cement fiber composite are visually detected and mathematically described. The technology of sample preparation, measurement technique and digital image processing is described, while advantages and disadvantages are discussed.
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Authors: Z.N. Ismarrubie, Han Lin Goh, S. Masuri, Hanafiah Yussof
Abstract: Mimosa Pudica (also known as Pokok Semalu) is an action plant with unique biological cell mechanism that has great potential to be explored for next generation biomechatronics devices. The motion principle of each petiole movement occurs by an organ of motion, called pulvinus. The behavior analysis of the Mimosa Pudica plant main pulvinus and petiole against external stimulations has been investigated. The response of the plant cell was observed by optical and scanning electron microscopes (SEM). External stimulation tests on Mimosa Pudica plant such as mechanical, electrical and light stimulations were conducted. Optical microscopy and SEM observations revealed the existence of red cells in the tertiary pulvinus. Mechanical stimulation results had shown a response time of approximately 2 seconds and a recovery time of 10 to 12 minutes for the leaves and 20 minutes for the petiole. Bending force of the petiole of Mimosa Pudica was also measured. The torque generated by the bending of petiole was found to increase exponentially as the pulvinus diameter increased. A torque of 30.91 g mm was generated from the bending of a petiole with 1.5 mm pulvinus diameter. The lifting potential of the Mimosa Pudica was tested using loadings with increments of 0.42 gram. The plant responded to electrical stimulation of 1.3 Ampere and displayed side effect. The light sensitivity region of Mimosa Pudica was obtained through light stimulation using a full spectrum daylight bulb, and ranges from 50 to 300 lux. Signal transmission to neighbouring structures was observed when the leaf was stimulated with threatening stimulus, with the signal speed achieving 0.8 cm/s. Movement mechanism of Mimosa Pudica is believed to be triggered by signal through receptor cells. It was found that the torque generated during petiole lifting is relatively higher than that during petiole bending.
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Authors: Qing Qing Liu, Ya Li Peng, Fei Hu
Abstract: To meet the needs of consumers desiring for weight-loss food, investigation on phase characteristics of milk protein-konjac glucomannan multicomponent systems with κ-carrageenan was carried out to simulate healthy ice cream product. Methods of rheology, light scattering and microscopy were used to examine the mechanism underlying the transformation of phase behavior. Addition of κ-carrageenan (0%) evidently showed extensive phase separation that casein micelles concentrated into an irregular discrete phase. A high degree of emulsification of spherical micelle droplets occurring in the continuous serum phase prevented bulk phase separation when the κ-carrageenan concentration increased (0.025%, 0.05%). The analysis of rheological characteristics revealed that multicomponent systems with higher κ-carrageenan concentration were more viscous and showed higher thixotropy behavior due to intense interactions between κ-carrageenan and casein micelles. Frequency independence of G and G was also greatly enhanced as concentration of κ-carrageenan increased. Moreover, differences of size distribution evidenced the structure formation of systems in presence of κ-carrageenan. The joint effects of κ-carrageenan helix aggregation and the interaction between casein micelles and κ-carrageenan were contributed to phase behavior transformation.
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Authors: Suejit Pechprasarn, Pakapron Pimonsakonwong, Prakaikan Kulikhandan, Phitsini Suvarnaphaet, Weeratouch Pongruengkiat, Phimonkhae Suksan, Naphat Albutt
Abstract: Microscope add-on toolkits for smartphone and tablet have become more widely available in the market. Although, these are sufficient to meet the demand and requirements of standard users, e.g. educational usage, these devices, in fact, do not meet the medical and biological requirements where fluorescence imaging plays a crucial role. In this paper, we introduce our innovative design in compact fluorescence microscope for smartphone and tablet. The device enables users to take fluorescent images at several excitation wavelengths using compact sources and filters.
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Authors: Lenka Klakurková, Eduard Hégr, Ladislav Čelko, Tomáš Podrábský, Martin Juliš, Michaela Remešová, Jiří Švejcar
Abstract: Hard anodized layers were produced by two different manufacturers on the same type of aluminium alloy on a vacuum pump part of complex shape. The sulphuric acid/water solution was used to produce alumina layers, which were subsequently sealed in demineralized water. A comparative analysis based on metallographic methodology, with the aim to control the stability of alumina formation process and to identify its defects, was performed by means of light and scanning electron microscopy, surface profilometry and microhardness measurements. To determine the thickness of alumina layers, the image analysis was also used.
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