Energy Dispersive X-ray Micro Research Articles

Characterization of a Careya Arborea Bast Fiber as Potential Reinforcement for Light Weight Polymer Biodegradable Composites

ABSTRACT In the current work, the experiments on Careya Arborea (CA) fiber have been carried out for physio-chemical properties, thermal properties, and other characteristics. The chemical composition of CA fiber has been identified with rich content of cellulose (71.17%), lignin (14.95%), hemicellulose (27.86%), small amount of wax (0.18%) and ash (0.78%). CA fiber crystallinity index of 85.05% with crystalline size 7.40 nm is seen from XRD analysis. The surface morphology and roughness of the CA fiber have been investigated using scanning electronic microscopy and found an average diameter of 28 nm, Atomic force microscopy (AFM) with an average surface roughness of 33.458 nm and Energy dispersive X-ray micro analyzer to confirm the element configuration. Thermal properties of CA fiber were also measured by Thermogravimetry analysis and Differential scanning calorimeter analysis. The results showed the thermal stability of upto 248°C and degradation temperature of 385°C which is suitable for polymer composite fabrication. The chemical functional groups available in CA fiber were identified by FTIR. The density of the CA fiber was 1140 kg/m3 which is lower than the existing fibers and exhibited respectable tensile properties. The results were compared with latest natural fibers to discern the versatility in various applications such as aerospace, automotive and automobile industries.

Energy-dispersive X-ray micro Laue diffraction on a bent gold nanowire.

This article reports on energy-dispersive micro Laue (µLaue) diffraction of an individual gold nanowire that was mechanically deformed in three-point bending geometry using an atomic force microscope. The nanowire deformation was investigated by scanning the focused polychromatic X-ray beam along the nanowire and recording µLaue diffraction patterns using an energy-sensitive pnCCD detector that permits measurement of the angular positions of the Laue spots and the energies of the diffracted X-rays simultaneously. The plastic deformation of the nanowire was shown by a bending of up to 3.0 ± 0.1°, a torsion of up to 0.3 ± 0.1° and a maximum deformation depth of 80 ± 5 nm close to the position where the mechanical load was applied. In addition, extended Laue spots in the vicinity of one of the clamping points indicated the storage of geometrically necessary dislocations with a density of 7.5 × 1013 m-2. While µLaue diffraction with a non-energy-sensitive detector only gives access to the deviatoric strain, the energy sensitivity of the employed pnCCD offers absolute strain measurements with a resolution of 1%. Here, the residual strain after complete unloading of the nanowire amounted to maximum tensile and compressive strains of the order of +1.2 and -3%, which is comparable to the actual resolution limit. The combination of white-beam µLaue diffraction using an energy-sensitive pixel detector with nano-mechanical testing opens up new possibilities for the study of mechanical behavior at the nanoscale.

Study on characterization of Furcraea foetida new natural fiber as composite reinforcement for lightweight applications

The exploration of new natural fibers in the field of polymer composites can contribute to increase the invention of natural reinforcements and expand their use in possible applications. In the present work, the physico-chemical, thermal, tensile and morphological properties of Furcraea foetida (FF) fiber are presented for the first time. Chemical analysis results shows that FF has relatively higher cellulose (68.35%) with lower hemicelluloses (11.46%) and lignin (12.32%). Structural analysis of FF was conducted by Fourier transform infrared and 13C (CP-MAS) nuclear magnetic resonance spectroscopy. X-ray diffraction (XRD) analysis evidenced that FF has crystallinity index of 52.6% with crystalline size of 28.36nmThe surface morphology of FF was investigated by scanning electron microscopy (SEM), energy dispersive X-ray micro analyzer (EDX) and atomic force microscopy (AFM). The thermogravimetric analysis (TGA) reveals thermal constancy of the fiber upto 320.5°C with the kinetic activation energy of 66.64kJ/mol, which can be used as reinforcements in thermoplastic green composite whose working temperatures is below 300°C. The FF results were compared with those of other natural fibers, and indicated as a suitable alternative source for composite manufacture.

Investigation on Machinability and Damping Properties of Nickel–Phosphorus Coated Boring bar

Chatter or self-excited vibration during machining process is always a serious problem which reduces intended dimensional accuracy. This investigation is mainly about reducing induced vibration through the electroless coating of nickel–phosphorus (Ni–P) on high carbon steel (EN 31) boring bar. The high carbon steel (EN31) substrate has been electroless coated with nickel–phosphorus at varying pH values (4, 5 and 6), and the damping effect of pH values on material deposition has been investigated. The coated substrate was subjected to heat treatment process and the influence of pH values and heat treatment process on structural stabilities of the coated specimens were analyzed using impact hammer test, and scanning electron microscope, energy-dispersive X-ray micro analysis and X-ray diffraction technique were used to study the structural changes in the Ni–P-coated boring bars. The pH values and heat treatment processes were found to play a significant role in improving the damping properties of the boring bars. The boring bar coated at 4 pH values resulted in better deposition of nickel and phosphorous over the substrate and offered better damping properties to the substrate. The heat treatment process on the coated specimen was found to render a crystalline structure to the substrate, thus offering improved damping proprieties to the materials.

Photocatalytic degradation of chloramphenicol and tartrazine using Ag/TiO2 nanoparticles

Photocatalytic degradation of chloramphenicol (CAP) and tartrazine (TAZ) was studied in the aqueous suspensions of silver-modified TiO2 (Ag/TiO2) nanoparticles under ultraviolet (UV) light irradiation. Ag/TiO2 nanoparticles were prepared with chemical reduction method and characterized by X-ray diffraction (XRD), scanning electron micrographs (SEM), energy dispersive X-ray micro analysis (EDX), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS) techniques. XPS measurement indicates that Ag mainly exists in the Ag0 state on the TiO2 nanoparticles surface. The effects of the operational parameters, such as silver concentration, photocatalyst loading, initial substrate concentration, light intensity, and calcination temperature were evaluated. It was found that the photocatalytic efficiency of TiO2 nanoparticles for the degradation of CAP and TAZ can be significantly improved by depositing an optimum amount of Ag nanoparticles. By comparing the removal efficiency of CAP and TAZ at the similar conditions, it was observed that the photodegradation rate of TAZ was faster than that of CAP. Total organic carbon (TOC) removal was measured at optimum conditions to quantify the mineralization of the pollutants. Above 84 and 89% mineralization of CAP and TAZ was observed using 120 min irradiation.

Granulation of Fe–Al–Ce trimetal hydroxide as a fluoride adsorbent using the extrusion method

Iron–aluminum–cerium hydroxide (Fe–Al–Ce), which has high fluoride (F) adsorption capacity, was granulated via extrusion with cross-linked poly (vinyl alcohol) (PVA) as the binder. The optimum granulation conditions for acquiring an adsorbent with a high F adsorption capacity and compression strength were: binder/Fe–Al–Ce powder ratio, 1.4; average cylinder diameter of granules, 1.6mm; and drying temperature, 65°C. The granulated Fe–Al–Ce (GFAC) exhibited a Langmuir maximum adsorption capacity of 51.3mgg−1 at pH 7.0±0.2. The GFAC in columns exhibited an accumulated F adsorption capacity of 5.7mgg−1 and 3.2mgg−1 at the breakthrough point (1.0mgFl−1) for treatment of F-spiked tap water (pH 7.8±0.2) and F-bearing groundwater (pH 8.2±0.2), respectively, which is several times higher than most reported F adsorbents under the same conditions. Energy dispersive X-ray micro analysis (EDX) showed that F was distributed evenly in the cross-section of the used GAFC, suggesting that most active sites inside the GFAC were available for F removal. A regeneration method using NaAlO2 solution to desorb F from the used GFAC was developed, permitting the GFAC to keep over 60% of its F adsorption capacity even after four adsorption–regeneration cycles. The results demonstrated that GFAC was superior in F adsorption performance to conventional adsorbents such as activated alumina.

Thermal analysis of kidney stones and their characterization

Thermal decomposition and structural characterization of three human kidney stones (KS1–KS3) extracted from patients of Eastern Bohemia have been carried out using X-ray powder diffraction systems (XRD), scanning electron microscope with energy dispersive X-ray micro analyser (SEM-EDX) and differential thermal analysis (DTA). The samples KS1 and KS2 solely consisted of calcium oxalate monohydrate (a.k.a. whewellite, CaC2O4·H2O). The third sample, KS3, was formed from calcium oxalate dihydrate (weddellite, CaC2O4·2H2O), calcium oxalate monohydrate, and hydroxyapatite (HA, Ca10(PO4)6(OH)2). Thermal measurements were carried out in the range between room temperature and 1,230 °C. XRD analysis was utilized to investigate the change of phases at 800 and 1,230 °C.

Catalytic performance and kinetics of Au/γ-Al 2O 3 catalysts for low-temperature combustion of light alcohols

Au/γ-Al 2O 3 catalysts were prepared by deposition-precipitation method for the catalytic combustion of low concentration alcohol streams (methanol, ethanol, iso-propanol and n-propanol). The catalysts were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffractometry (XRD) and energy dispersive X-ray micro analysis (EDS) techniques. The XPS results showed that there was only Au 0 on the surface of catalysts. The XRD patterns showed that Au was presumably highly dispersed over γ-Al 2O 3. The temperatures for complete conversion of methanol, ethanol, iso-propanol and n-propanol with concentration of 2.0 g/m 3 were 60, 155, 170 and 137 ?, respectively, but they were completely mineralized into CO 2 and H 2O at 60, 220, 260 and 217 ? respectively over the optimized catalyst. The activity of the catalyst was stable in 130 h. The kinetics for the catalytic methanol elimination followed quasi-first order reaction expressed as r=0.652 8 c 0+0.084 2. The value of apparent activation energy is 54.7 kJ/mol in the range of reaction temperature.

Photovalorisation of pentafluorobenzoic acid with platinum doped TiO 2

Pt-doped TiO 2 has been prepared and characterized by various surface analytical methods such as BET surface area, scanning electron micrographs (SEM), X-ray diffraction (XRD), energy dispersive X-ray micro analysis (EDX) and diffuse reflectance spectroscopy (DRS). Photodefluoridation of pentafluorobenzoic acid (PFBA) to fluoride ions has been carried out using TiO 2 and Platinum doped TiO 2 with UV-C (200–300 nm) light. The defluoridation was monitored by the ionometer with fluoride ion selective electrode. Photodeposition of 1.5% Platinum on the surface of TiO 2 enhances its photoactivity in pentafluorobenzoic acid defluoridation. In order to optimize the working conditions, effects of pH and initial PFBA concentration were analyzed. Addition of inorganic oxidizing species KIO 4, H 2O 2, (NH 4)S 2O 8 and KBrO 3 strongly influenced the photocatalytic defluoridation of PFBA. The significant enhancement in the Pt-TiO 2 photoactivity under UV irradiation can be ascribed to the platinum deposits, acting as electron traps on the Pt-TiO 2 surface. The fluoride ions formed during photodefluoridation can be used for the production of CaF 2.

Nano-Ag particles doped TiO 2 for efficient photodegradation of Direct azo dyes

Silver nanoparticles doped TiO 2 has been prepared and characterised by surface analytical methods such as BET surface area, scanning electron micrographs (SEM), X-ray diffraction (XRD), energy dispersive X-ray micro analysis (EDX), electron spin resonance (ESR) and diffuse reflectance spectroscopy (DRS). We have investigated the photocatalytic degradation of two Direct diazo dyes, Direct red 23 (DR 23) and Direct blue 53 (DB 53) in the aqueous suspensions of TiO 2 and Ag deposited TiO 2 nanoparticles under UV-A light irradiation in order to evaluate the various effects of silver deposition on the photocatalytic activity of TiO 2. The presence of silver in TiO 2 was found to enhance the photodegradation of DR 23 and DB 53. The higher activity of silver doped TiO 2 is due to the enhancement of electron–hole separation by the electron trapping of silver particles.

Surface characterization of artificial corrosion layers on copper alloy reference materials

This paper describes the surface characterization of artificial patina layers on five different copper alloys. The chemical composition of the examined bronzes covers the major families of archaeological copper alloys from antiquity until the Roman period. The patina layers of the five samples were formed under identical conditions by electrochemical means. Light microscopy, scanning electron microscopy with energy dispersive X-ray micro analysis (SEM–EDX) and Fourier transform infrared spectroscopy (FTIR) were used to describe the main properties of the patina layers. The results were interpreted and classified according to an existing corrosion model for copper alloys.

Sideroelastosis of pulmonary vessels after welder dust exposure

Sideroelastosis pulmonum was first described by Ceelen (1931) and Gellerstedt (1939), mentioning an idiopathic type, but also vascular alterations in chronic pulmonary congestion. We analysed the question wether secondary sideroelastosis can be demonstrated also in lungs after previous welder dust exposure. Lung samples of 43 patients and deceased with various exposure periods to welder dust were investigated. On each sample, light microscopical, scan electron microscopical and energy dispersive x-ray micro analyses (EDX) were performed. In six samples (14%) vascular alterations in the area of denaturated elastic fibres with siderophilic "impregnation" were seen, corresponding to the features described by von Ceelen and Gellerstedt. Giant cell or granulomatous reactions, however, were present only in exceptional cases. This phenomenon was seen mostly in cases of marked local siderin deposits and reactive fibrosis. Using EDX, a number of metals characteristic for welder dust (Al, Ti, Cr, Ni) as well as iron were found in siderophages. No other metal than iron was detected in siderophilic elastic fibres using EDX. Causal pathogenetically, a correlation between increased iron uptake connected with welding particles and sideroelastosis of the vessel walls has to be established. However, in formal pathogenesis, other factors such as local perfusion disturbances due to fibrotic processes after exposure to harmful substances must be taken into consideration.

Mammalian Tuft (Brush) Cells and Chloride Cells of Other Vertebrates Share a Similar Structure and Cytochemical Reactivities.

The function of the tuft (brush) cells is still obscure. From the morphological similarities between tuft cells and chloride cells in the fish gill, which secrete or absorb NaCl, it was hypothesized that mammalian tuft cells may share functional roles similar to chloride cells. To test this hypothesis, the following points were studied on rat tuft cells. 1) The ultrastructural changes of bile duct tuft cells after secretin stimulation showed a moderate increase of basolateral membrane infoldings and a decrease of tubulovesicles in the apical cytoplasm. 2) The ultrastructural changes of tuft cells in the gastric groove of the rats on a high NaCl diet for 4 weeks, which were directly exposed to a high NaCl diet, and showed a marked shortening of microvilli and an appearance of numerous large vacuoles in the cytoplasm. 3) Cytochemical demonstrations of chloride and sodium ions were analyzed by energy-dispersive X-ray micro analysis (EDX). Massive reaction products of chloride were found in the apical cytoplasm of some tuft cells of fasting rats 5 min after secretin stimulation, but they were virtually absent in the tuft cells without stimulation. Reaction products of sodium were predominantly found along the basolateral membranes of tuft cells 5 min after secretin stimulation, but they were absent along those of tuft cells without stimulation. 4) Immunohistochemical demonstration of Na+/K+-ATPase, which is highly reactive in chloride cells of the fish gill, was positive in the tuft cell cytoplasm. These findings indicate that the mammalian tuft cells have properties similar to chloride cells in other vertebrates. By monitoring the electrolyte concentration with their long microvilli, tuft cells may regulate concentrations of electrolytes, probably NaHCO3, in the secretory fluid of hollow organs.

微粉炭燃焼フライアッシュ中の炭素分の性状

Fly ashes E and G those discharged from a same pulverized coal combustion boiler were classified into two components, such as smaller fly ash particle under 38, a m and larger fly ash particle above 125 μm. The carbon cotained in both components were separated from fly ash by using the Ultrasonic Oil Agglomeration method. Properties of separated carbons were investigated by applying the X-ray diffraction, SEM (Scanning Electron Microscope), EDX (Energy Dispersive X-Ray Micro Analyzer) and TGA (Thermogravimetric Analysis). Following results are obtained.(1) The carbon remains in the larger fly ash as the unburned char, and that cotained in smaller fly ash are carbon black and rock carbon.(2) Significant differences of the carbon contents and their properties between the fly ashes E and G are found. The carbon content in smaller components of fly ash G is fairly greater than that in smaller components of fly ash E, although the coal G shows a good combustibility.These observations of the properties of carbon containing in fly ash present significant informations on the for rational operation and control in the process of pulverized coal combustion process.

Comparative analysis of synthetic polymers using combinations of three analytical methods

The use of three analytical techniques for forensic investigation of synthetic polymers is described. These techniques are: pyrolysis infrared spectrometry (PyIR), pyrolysis gas chromatography (PyGC) and energy dispersive X-ray micro probe analysis (EPMA). Whereas the first two methods have been described previously, the microanalytical procedure is new. It may be used in combination with one of the other two techniques for the discrimination between polymer samples.

INVESTIGATION INTO THE CAUSES OF PREMATURE CORROSION OF PRE-FABRICATED STEEL FACTORY BUILDING

Premature corrosion of steel roof panels of a prefabricated factory building was reported just two months’ after installation. In order to find out the causes of this corrosion, physical investigation of the affected roof was carried out and samples of the panels and relevant information were collected. Laboratory tests were carried out on the samples using light optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray micro analysis (EDX) and tensile tests. Test results show that the steel roof was constructed from painted as well as Al-Zn coated steel sheet, conforming to ASTM A 792M Grade 340 and ASTM A 792M-A150. Analysis of other results suggests that the rusts were superficial in nature and they did not start from the steel sheet of the roof panels. Based on the superficial nature of the rust spots, their morphology, chemical analysis etc., it is believed that rust spots were caused by the corrosion of steel swarfs that deposited on the roof panels. The swarfs originated from drilling, cutting and riveting operations during installation. Proper cleaning of the roof immediately after installation could have avoided the problem. Importance of awareness about the danger of improper cleaning and regular maintenance of roof panels after installation is discussed.Keywords: Premature corrosion; galvanized; steel debris; roof panel; superficial.DOI: 10.3329/jme.v40i2.5349Journal of Mechanical Engineering, Vol. ME 40, No. 2, December 2009 90-94