Experimental identification and characterization of the effects of contaminants in the wheel—rail contact

Author(s):  
S Descartes ◽  
C Desrayaud ◽  
Y Berthier

Previous results have highlighted the presence of a natural third body ranging in thickness from a few micrometres to several dozen micrometres on the rail and wheel. The third body layer, initially composed of particles stemming from the wheels and rails, flows into the contact to accommodate local sliding inside it. The work presented in this paper focuses on the identification of contaminants whose influence on the wheel—rail contact is significant. This influence can be considered as significant if it enters the contact, affects surface properties, modifies the third body layer, and possibly damages or protects the rail. The third body layer can progressively absorb and assimilate solid (ballast stone, sand) and fluid (oil) contaminants existing on rails, and thus reduce their negative consequences on rail lifetime. These phenomena are the result of the exchange of third body flows between the wheel and rail. A high-speed camera was used for this experimental study performed on a real site. The analyses of the dynamic images are coupled with tribological analyses of the surfaces by scanning electron microscopy and X-ray energy dispersive analysis.

2018 ◽  
Vol 7 (2) ◽  
pp. 131-137 ◽  
Author(s):  
Yanuar Hamzah ◽  
Muhammad Mardhiansyah ◽  
Liong Nyuk Firdaus

The objective of this research is to determine the rare earth elements (REEs) from themonazite minerals content of several tin tailing sands (TTS)of ex-tin mining area in Kuala Raya Singkep Island, Indonesia. We used the energy dispersive analysis of  X-ray (EDAX)-scanning electron microscopy (SEM) and x-ray diffraction (XRD) to characterize the contents of the samples. The coupled analytical of XRD with SEM/EDX approach enabled to be used for mineralogical identification on the heavy mineral as a rapid determination approach. The analysis of the samples indicates only the presence of REEs including lanthanum (La), cerium (Ce), and thorium (Th) are consistent with the identification of monazite and minerals in the tailing sand. The results show that the average REEs consist of La at 0.2 .%, Ce at 7.8 %, and Th at 2.0% respectively. It is concluded that monazite minerals in TTS has an economic potential to be developed. These monazite minerals can be used as material for semiconductor devices.   


2014 ◽  
Vol 789 ◽  
pp. 122-129
Author(s):  
Mei Ling Shao ◽  
Qing Yang ◽  
Jing He ◽  
Benjamin S. Hsiao

A novel biomaterial poly (butylene carbonate) (PBC) was used to fabricate aligned nanofibresby electrospinning with a high-speed transfer roller as the receiving device. The morphology of the fibers was evaluated by scanning electron microscopy (SEM). To expand the application of the biomaterial, cold plasma treatment and induced grafting technology were applied to improve its hydrophilicity and biocompatibility. The properties of the fibers, pretreated withhelium and following grafting with gelatin,were evaluated with X-ray photoelectron spectroscopy. The cytotoxicity of the materials to Schwann cells (RSC96) was investigated. Results indicated that aligned nanofibers can be received at high rotation speed.After plasma pretreatment, the activity of the surface was improved significantly and the grafting reaction was successful. SEM observations showed that cells can grow on the fibersurface along the direction of fiberorientation after seeding with RSC96 for 3 and 5 days. Modification of the nanofibersurface with gelatin significantly increased RSC96 attachment and proliferation.


2019 ◽  
Vol 948 ◽  
pp. 279-286
Author(s):  
Anggraeni Kumala Dewi ◽  
Ariswan

These study aims determine the characterization of structure and chemical composition of crystal Sn(Se0.8Te0.2). The growth of crystal Sn(Se0.8Te0.2) is obtained by preparation outcome through Bridgman Technique. Hence, characterized by using the XRD (X-Ray Diffraction) for to determine the crystal structure, SEM (Scanning Electron Microscopy) to determine the surface morphology, and EDAX (Energy Dispersive Analysis of X-ray) to determine the chemical composition. The four samples are characterized results indicate that crystal Sn(Se0.8Te0.2) has orthorhombic structure with the results of the samples I and III have the highest intensity. SEM characterization result for sample I and III indicate that the formation of crystal Sn(Se0.8Te0.2) is characterized by the presence of grains. Based on the results of EDAX, it is known that the crystal Sn(Se0.8Te0.2) contains elements of Sn, Se, and Te with a percentage of the chemical composition of the sample I is Sn = 39.85%, Se = 36.09%, and Te = 2.57 %. Comparison the molarity of the sample I is Sn: Se: Te is 1: 0.90: 0.10.


2015 ◽  
Vol 33 (2) ◽  
pp. 301-305 ◽  
Author(s):  
Girish H. N. ◽  
Basavalingu B. ◽  
Shao G.-Q. ◽  
Sajan C. P. ◽  
S. K. Verma

AbstractGadolinium aluminum perovskite (GdAlO3, GAP) is a promising high temperature ceramic material, known for its wide applications in phosphors. Polycrystalline gadolinium aluminum perovskites were synthesized using a precursor of co-precipitate gel of GdAlO3 by employing hydrothermal supercritical fluid technique under pressure and temperature ranging from 150 to 200 MPa and 600 to 700 °C, respectively. The resulted products of GAP were studied using the characterization techniques, such as powder X-ray diffraction analysis (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDX). The X-ray diffraction pattern matched well with the reported orthorhombic GAP pattern (JCPDS-46-0395).


Author(s):  
R. E. Herfert

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.


Author(s):  
Marc H. Peeters ◽  
Max T. Otten

Over the past decades, the combination of energy-dispersive analysis of X-rays and scanning electron microscopy has proved to be a powerful tool for fast and reliable elemental characterization of a large variety of specimens. The technique has evolved rapidly from a purely qualitative characterization method to a reliable quantitative way of analysis. In the last 5 years, an increasing need for automation is observed, whereby energy-dispersive analysers control the beam and stage movement of the scanning electron microscope in order to collect digital X-ray images and perform unattended point analysis over multiple locations.The Philips High-speed Analysis of X-rays system (PHAX-Scan) makes use of the high performance dual-processor structure of the EDAX PV9900 analyser and the databus structure of the Philips series 500 scanning electron microscope to provide a highly automated, user-friendly and extremely fast microanalysis system. The software that runs on the hardware described above was specifically designed to provide the ultimate attainable speed on the system.


2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Liu Liu ◽  
Decai Gong ◽  
Zhengquan Yao ◽  
Liangjie Xu ◽  
Zhanyun Zhu ◽  
...  

Abstract Historically, sutras played an important role in spreading Buddhist faith and doctrine, and today these remain important records of Buddhist thought and culture. A Mahamayuri Vidyarajni Sutra with polychrome paintings was found inside the cavity on top of the Nanmen Buddhist pagoda, built in the early Tang dynasty (618–627 CE) and located in Anhui Province, China. Textile was found on the preface which is strongly degraded and fragile. Unfortunately, the whole sutra is under severe degradation and is incomplete. Technical analysis based on scientific methods will benefits the conservation of the sutra. Optical microscopy (OM), micro-Raman spectroscopy combined with optical microscope (Raman), scanning electron microscopy in combination with energy dispersive X-ray analysis (SEM–EDS) and Fourier Transform Infrared Spectroscopy (FTIR) were used to characterize the pigment and gilded material, as well as the paper fiber and textile. Pigments such as cinnabar, minium, paratacamite, azurite, lead white were found. Gilded material was identified as gold. A five-heddle warp satin, made of silk, was found as the textile on the preface of the sutra. The sutra’s preface and inner pages were made of paper comprised of bamboo and bark. As a magnificent yet recondite treasure of Buddhism, the sutra was analyzed for a better understanding of the material. A conservation project of the sutra will be scheduled accordingly.


2012 ◽  
Vol 620 ◽  
pp. 314-319
Author(s):  
Nur Amira Mamat Razali ◽  
Fauziah Abdul Aziz ◽  
Saadah Abdul Rahman

Hardwood is wood from angiosperm trees. The characteristic of hardwood include flowers, endosperm within seeds and the production of fruits that contain the seeds. This paper aims to discuss the preparation and characterization of cellulose obtained from hardwood. The hardwood Merbau (Intsia bijuga) was chosen as raw material in this study. Alkaline treatment and delignification methods were used for the preparation of cellulose. Acid hydrolysis was employed to produce cellulose nanocrystal (CNC). The treated and untreated samples were characterized using x-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The final product, from both trated and untreated samples were then compared.


2011 ◽  
Vol 415-417 ◽  
pp. 642-647
Author(s):  
En Zhong Li ◽  
Da Xiang Yang ◽  
Wei Ling Guo ◽  
Hai Dou Wang ◽  
Bin Shi Xu

Ultrafine fibers were electrospun from polyacrylonitrile (PAN)/N,N-dimethyl formamide (DMF) solution as a precursor of carbon nanofibers. The effects of solution concentration, applied voltage and flow rate on preparation and morphologies of electrospun PAN fibers were investigated. Morphologies of the green fibers, stabilized fibers and carbonized fibers were compared by scanning electron microscope (SEM). The diameter of PAN nanofibers is about 450nm and the distribution of diameter is well-proportioned. Characterization of the elements changes of fibers were performed by X-ray photoelectron spectroscopy (XPS).


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