Energy-dispersive X-ray Spectroscopy for the Quantitative Analysis of Pyrite Thin Specimens

To explore ways to improve the accuracy of quantitative analysis of samples in the micrometer to nanometer range of magnitudes,we adopted analytical transmission electron microscopy(AEM/EDS)for qualitative and quantitative analysis of pyrite materials.Additionally,the k factor of pyrite is calculated experimentally.To develop an appropriate non-standard quantitative analysis model for pyrite materials,the experimentally calculated k factor is compared with that estimated from the non-standard quantitative analytical model of the instrument software.The experimental findings demonstrate that the EDS attached to a TEM can be employed for precise quantitative analysis of micro-and nanoscale regions of pyrite materials.Furthermore,it serves as a reference for improving the results of the EDS quantitative analysis of other sulfides.

Energy Dispersive X-Ray Spectroscopy of the Sohnari Member of Laki Formation from Southern Indus Basin of Pakistan

This study determines the geochemical and depositional environment analysis of the sediments of the Sohnari Member of the Laki Formation, Northern Kirthar Fold Belt of Pakistan. The Energy-Dispersive-X-Ray Spectroscopy (EDS) technique is used for the detection of major elements and the effects of shifting depositional climatic conditions of six representative samples which were acquired from the Sohnari Member of the Laki Formation at Lakhra area, Sindh, Pakistan. The sedimentological studies clarify that the sediments the Sonahri Member are relatively immature and most migrated in clastic mode. The availability of Silica shows that the Member was formed due to biochemical precipitation and detrital mode and was deposited at a fast rate of sediment deposition under the fluvio-deltaic depositional system. This is also deduced that the rapid rate of sediment deposition might be created a reducing atmosphere and allowing for the mineralization of sulphur.

Gap States of ZnO Thin Films by New Methods:Optical Spectroscopy,Optical Conductivity and Optical Dispersion Energy

The optical reflectance and transmittance spectra in the wavelength range of 300-2500 nm are used to compute the absorption coefficient of zinc oxide films annealed at different post-annealing temperatures 400, 500 and 600°C.The values of the cross point between the curves of the real and imaginary parts of the optical conductivity ɑ_1 and ɑ_1 with energy axis of films exhibit values that correspond to optical gaps and are about 3.25-3.3 eV. The maxima of peaks in plots dR/dλ and dT/dλ versus wavelength of films exhibit optical gaps at about 3.12-3.25 eV.The values of the fundamental indirect band gap obtained from the Tauc model are at about 3.14-3.2 eV. It can be seen that films annealed at 600°C have the minimum indirect optical band gap at about 3.15 eV. The films annealed at 600°C have Urbach＇s energy minimum of 1.38 eV and hence have minimum disorder. The dispersion energy d of films annealed at 500°C has the minimum value of 43 eV.

Possible Relevance of the Allende Meteorite Conditions in Prebiotic Chemistry: An Insight into the Chondrules and Organic Compounds

The study of the mineral and organic content of the Allende meteorite is important for our understanding of the molecular evolution of the universe as well as the ancient Earth. Previous studies have characterized the magnetic minerals present in ordinary and carbonaceous chondrites, providing information on the evolution of magnetic fields. The interaction of organic compounds with magnetic minerals is a possible source of chemical diversity, which is crucial for molecular evolution. Carbon compounds in meteorites are of great scientific interest for a variety of reasons, such as their relevance to the origins of chirality in living organisms. This study presents the characterization of organic and mineral compounds in the Allende meteorite. The structural and physicochemical characterization of the Allende meteorite was accomplished through light microscopy, powder X-ray diffraction with complementary Rietveld refinement, Raman and infrared spectroscopy, mass spectrometry, scanning electron microscopy, and atomic force microscopy using magnetic signal methods to determine the complex structure and the interaction of organic compounds with magnetic Ni-Fe minerals. The presence of Liesegang-like patterns of chondrules in fragments of the Allende structure may also be relevant to understanding how the meteorite was formed. Other observations include the presence of magnetic materials and nanorod-like solids with relatively similar sizes as well as the heterogeneous distribution of carbon in chondrules. Signals observed in the Raman and infrared spectra resemble organic compounds such as carbon nanotubes and peptide-like molecules that have been previously reported in other meteorites, making the Mexican Allende meteorite a feasible sample for the study of the early Earth and exoplanetary bodies.

Process mineralogy and characteristic associations of iron and phosphorus-based minerals on oolitic hematite

The chemical compositions,mineralogical characteristics,as well as dissemination of iron-and phosphorus-based minerals were studied for the E’xi oolitic hematite from western Hubei Province in China by using chemical analysis,optical microscope,electron probe micro-analyzer(EPMA)and energy dispersive spectroscopy(EDS).It is found that this kind of oolitic hematite ore contains 47.71%TFe,10.96%SiO_2,as well as 0.874%P,with hematite as the dominant Fe-bearing minerals,and quartz,chamosite,illite and cellophane as main gangue minerals.The microscope examination showed that the ore has an oolitic structure,with some ooids principally formed by a series of concentric layers of hematite collophanite around nucleus that is hematite in the association with collophanite.Based on the EPMA and EDS analysis,it can be known that some ooids are primarily composed of hematite and collophanite.The separation can be achieved through fine grinding for those collophanite laminae with a higher P content.However,the dissemination of two minerals at the interface will result in the difficulty in effective separation.Besides,some ooids are made of chamosite with some nucleus formed of quartz,which is principally finely disseminated with hematite.In view of the close association and dissemination of iron-and phosphorus-based minerals in the ooids,it is found that the process of stage-grindings and stage-separations can be adopted to effectively increase the iron recovery and decrease the P content in the concentrate to some extent.

New approaches to characterizing urban air particles in central London

Atmospheric particles in central London during July 1996 have been apportioned to sources by two complimentary techniques: (1) morphological characteristics, determined using high power light microscopy; (2) chemical composition determined by energy dispersive spectroscopy. During the study period, the majority of particles were found to be either biological in origin, or from vehicle related combustion processes. Trends in the latter group of particles are explored further. Numbers of particles per cubic metre were determined at an hourly resolution over a period of six days, and were found to be significantly correlated with other traffic pollutants such as benzene and 1,3 butadiene, although there is no relationship with mass of PM10 as measured by a nearby UK Government monitoring station. We suggest in this paper that numbers of particles from car exhausts are more representative of traffic pollution than current estimates which use monitoring by mass.

Analysis of precipitation in a Cu-Cr-Zr alloy

Precipites in Cu-0.42%Cr-0.21%Zr alloy were analyzed by using scanning electron microscope （SEM）, energy dispersive X-ray spectroscopy （EDXS） and transmission electron microscope （TEM）. After the solid solution was performed at 980℃ for 2 h, water-quenched and aged at 450℃ for 20 h, the precipite had a bimodal distribution of precipitate size. The coarse precipitates are pure Cr and Cu5Zr, the dispersed fine precipitate is CrCu2（Zr, Mg） and pure Cr ranging from 1 to 50 nm. The coarse phases formed during solidification and were left undissolved during solid solution. The fine precipitates are the hardening precipitates that form due to decomposition of the supersaturated solid solution during aging.

Mechanism research on arsenic removal from arsenopyrite ore during a sintering process

The mechanism of arsenic removal during a sintering process was investigated through experiments with a sintering pot and arsenic-bearing iron ore containing arsenopyrite; the corresponding chemical properties of the sinter were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray diffraction (XRD), and scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). The experimental results revealed that the reaction of arsenic removal is mainly related to the oxygen atmosphere and temperature. During the sintering process, arsenic could be removed in the ignition layer, the sinter layer, and the combustion zone. A portion of FeAsS reacted with excess oxygen to generate FeAsO4, and the rest of the FeAsS reacted with oxygen to generate As2O3(g) and SO2(g). A portion of As2O3(g) mixed with Al2O3or CaO, which resulted in the formation of arsenates such as AlAsO4and Ca3(AsO4)2, leading to arsenic residues in sintering products. The FeAsS component in the blending ore was difficult to decompose in the preliminary heating zone, the dry zone, or the bottom layer because of the relatively low temperatures; however, As2O3(g) that originated from the high-temperature zone could react with metal oxides, resulting in the formation of arsenate residues. © 2017, University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg.

Determination of Water Diffusion Coefficients and Dynamics in Adhesive/Carbon Fiber Reinforced Epoxy Resin Composite Joints

To determinate the water diffusion coefficients and dynamics in adhesive/carben fiber reinforced epoxy resin composite joints, energy dispersive X-ray spectroscopy analysis（EDX） is used to establish the content change of oxy- gen in the adhesive in adhesive/carbon fther reinforced epoxy resin composite joints. As water is made up of oxygen and hydrogen, the water diffusion coefficients and dynamics in adhesive/carben fiber reinforced epoxy resin composite joints can be obtained from the change in the content of oxygen in the adhesive during humidity aging, via EDX analy-sis. The authors have calculated the water diffusion coefficients and dynamics in the adhesive/carbon fiber reinforced epoxy resin composite joints with the aid of beth energy dispersive X-ray spectroscopy and elemental analysis. The de- termined results with EDX analysis are almost the same as those determined with elemental analysis and the results al- so show that the durability of the adhesive/carbon fther reinforced epoxy resin composite joints subjected to silane cou- pling agent treatment is better than those subjected to sand paper burnishing treatment and chemical oxidation treat- ment.

Impact of open dumping of municipal solid waste on soil properties in mountainous region

This paper presents the effect of open dumping of municipal solid waste(MSW) on soil characteristics in the mountainous region of Himachal Pradesh, India. The solid waste of dumpsite contains various complex characteristics with organic fractions of the highest proportions. As leachate percolates into the soil, it migrates contaminants into the soil and affects soil stability and strength. The study includes the geotechnical investigation of dump soil characteristics and its comparison with the natural soil samples taken from outside the proximity of dumpsites. The geochemical analysis of dumpsite soil samples was also carried out by scanning electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDS).Visual inspection revealed that the MSW consists of high fraction of organics, followed by paper. The soil samples were collected from five trial pits in the dumpsites at depths of 0.5 m, 1 m and 1.5 m. Then the collected soil samples were subjected to specific gravity test, grain size analysis, Atterberg’s limit test,compaction test, direct shear test, California bearing ratio(CBR) test and permeability analysis. The study indicated that the dumpsite soils from four study regions show decreasing trends in the values of maximum dry density(MDD), specific gravity, cohesion and CBR, and increasing permeability as compared to the natural soil. The results show that the geotechnical properties of the soils at all four study locations have been severely hampered due to contamination induced by open dumping of waste.

Effect of liner and porcelain application on zirconia surface structure and composition

The purpose of this study was to determine if there is an effect of liner and porcelain application （layering and pressing techniques） on the surface of yttria-stabilized tetragonal zirconia polycrystals （Y-TZP）, which were exposed to permutations of liner, layered porcelain, and pressed porcelain. Scanning electron microscope （SEM）/energy dispersive spectroscope （EDS） was used to identify changes in composition and microstructure after removing liner and porcelain with hydrofluoric acid. Simulated aging was also conducted to determine the effect of liner and porcelain on low-temperature degradation. The control group had a typical equiaxed grain structure, referred to as unaffected. When covered with liner or porcelain, some areas changed in structure and composition and were termed affected. The frequency of affected sbructure decreased when liner was covered with either layered porcelain or pressed porcelain. There were statistical differences （P〈0.05） in the composition between affected and unaffected for zirconium （layered porcelain with liner： affected = 60% （0.8%） （m/m）, unaffected = 69% （4%）, layered porcelain without liner： affected = 59% （3%）, unaffected = 65% （3%）） and oxygen （layered porcelain with liner： affected = 35% （2%）, unaffected = 26% （4%）, layered porcelain without liner： affected = 35% （3%）, unaffected = 30% （2%））. However, there were statistical differences （P〈0.05） in the composition for zirconium and oxygen of the aged layered porcelain without liner only. The liner should not be used before porcelain application, especially when using the layering technique for zirconia restorations. Furthermore, pressing should be considered the technique of choice over layering.

Highly efficient and stable electrooxidation of methanol and ethanol on 3D Pt catalyst by thermal decomposition of In2O3 nanoshells

In this paper In2O3nanoshells have been synthesized via a facile hydrothermal approach. The nanoshells can be completely cracked into pony-size nanocubes by annealing, which are then used as a support of Pt catalyst for methanol and ethanol electrocatalytic oxidation. The prepared In2O3and supported Pt catalysts (Pt/In2O3) were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), field effect scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry and electrochemical impedance spectroscopy (EIS) were carried out, indicating the excellent catalytic performance for alcohol electrooxidation can be achieved on Pt/In2O3nanocatalysts due to the multiple active sites, high conductivity and a mass of microchannels and micropores for reactant diffusions arising from 3D frame structures compared with that on the Pt/C catalysts. © 2016 Science Press

Environmental boundary and formation mechanism of different types of H2S corrosion products on pipeline steel

To establish an adequate thermodynamic model for the mechanism of formation of hydrogen sulfide (H2S) corrosion products, theoretical and experimental studies were combined in this work. The corrosion products of API X60 pipeline steel formed under different H2S corrosion conditions were analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. A thermodynamic model was developed to clarify the environmental boundaries for the formation and transformation of different products. Presumably, a dividing line with a negative slope existed between mackinawite and pyrrhotite. Using experimental data presented in this study combined with previously published results, we validated the model to predict the formation of mackinawite and pyrrhotite on the basis of the laws of thermodynamics. The established relationship is expected to support the investigation of the H2S corrosion mechanism in the oil and gas industry. © 2017, University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg.

Palaeodiet of Miocene Producers and Depositional Environments:Inferences from the First Evidence of Microcoprolites from India

This paper reviews research on coprolites from India,providing the first evidence of microcoprolites from the early Miocene(Aquitanian)Khari Nadi Formation sedimentary succession,exposed about 1.5 km northeast of the village of Kotada,Kachchh(Kutch)District,Gujarat State,western India.Morphometric and size comparisons(in a statistical framework)with known coprolites from the Mesozoic-Cenozoic successions of India(including those recorded herein)and globally suggest that fishes were the likely producers of the Kotada coprolites.Scanning electron microscopy confirms the presence of fish dental remains within the coprolites,while both Scanning Electron Microscopy(SEM)and Energy Dispersive X-ray Spectroscopy(EDS)reveal the phosphatic nature of the microscopic coprolite specimens(recorded herein)hinting that the producer(s)were predominantly carnivorous(ichthyophagous)in their diet.Furthermore,X-Ray Fluorescence(XRF)analysis of the host and associated lithologies allows us to deduce that the Kotada coprolites were deposited in a shallow marine environment,with possible aerial exposure of the host lithology occurring at some point after deposition.To the best of our knowledge,the present report is the first record of microscopic fish coprolites from India,as well as being the first from the Aquitanian of India and the oldest Neogene record from India.

Performance of engineered cementitious composite containing stone slurry powder waste

Most of the materials used in engineered cementitious composite are fine in size to achieve ductile nature.Stone slurry powder(SSP)is an inert material obtained from stone industries as by-product which may cause hazardous impact on environment.In this research work,partial replacement of silica sand(SS)and fine sand(FS)by SSP with different contents(25%and 50%each)for making engineered cementitious composite has been explored.The performance was evaluated on the basis of strength,tensile strain,mid span deflection capacity,ultra-sonic pulse velocity and microstructure.Mechanical strength was found to be increased at 25%SSP in both replacements;whereas,strength decreased slightly at 50%replacement.Tensile strain,mid span deflection and quality of concrete were enhanced with increase in SSP content.Using SSP formed denser cementitious composite can help to save the natural resources and contribute in making green cementitious composite.

X-Ray and Mössbauer Study of Magnetic Black Sand from Mayotte Island

Natural magnetic black sands are known from several sites often located in areas of volcanic origin. Their elemental and mineral composition provides information on the geology of their territory and depends on several factors occurred during their formation. A sample of black sand was collected on the seashore of the island of Mayotte in the Indian Ocean and its magnetic part was investigated by means of energy dispersive X-ray spectroscopy (EDS), powder X-ray diffraction (XRD), and MÖssbauer spectroscopy at room temperature. The mineral composition is dominantly magnetite, in good agreement with samples collected in other sites of volcanic origin. Contrary to pure magnetite, a relevant fraction of Ti was detected by EDS. The 16% Ti and 1% Mn content increase the magnetite lattice parameter to 8.4312 (25) Å. The broadening of XRD lines pointed towards a significant degree of disorder. This was confirmed by MÖssbauer spectroscopy and is attributed to the presence of Ti replacing Fe in the magnetite lattice. The presence of Ti modifies the local magnetic field on the Fe sites, leading to a broader and more complex MÖssbauer transmission spectrum with respect to the one of pure magnetite. To study the effect of temperature, samples were heated for 12 hours to 600°C and 800°C in argon and to 1000°C in air. Annealing in argon did not improve the crystallinity while annealing in air caused a complete decomposition of magnetite into hematite and pseudobrookite.

Mossbauer,X-Ray and Magnetic Studies of Black Sand from the Italian Mediterranean Sea

The study of natural magnetic sands is instrumental to investigate the geological aspects of their formation and of the origin of their territory. In particular, Mossbauer spectroscopy provides unique information on their iron content and on the oxidation state of iron in their mineral composition. The Italian coast on the Mediterranean Sea near Rome is known for the presence of highly magnetic black sands of volcanic origin. A study of the room temperature Mossbauer spectrum, powder X-ray diffraction, energy dispersive X-ray spectroscopy, and magnetic measurements of a sample of black magnetic sand collected on the seashore of the town of Ladispoli is performed. This study reveals magnetite as main constituent with iron in both tetrahedral and octahedral sites. Minor constituents are the iron minerals hematite and ilmenite, the iron containing minerals diopsite, gossular, and allanite, as well as ubiquitous sanidine, quartz, and calcite.

FePO4-coated Li[Li0.2Ni0.13Co0.13Mn0.54]O2 with improved cycling performance as cathode material for Li-ion batteries

Li[Li0.2Ni0.13Coo.13Mn0.54]O2 cathode materials were synthesized by carbonate-based co-precipitation method, and then, its surface was coated by thin layers of FePO4. The prepared samples were characterized by X-ray diffraction （XRD）, field emission scanning electron micro- scope （FESEM）, energy-dispersive spectroscopy （EDS）, and transmission electron microscopy （TEM）. The XRD and TEM results suggest that both the pristine and the coated materials have a hexagonal layered structure, and the FePO4 coating layer does not make any major change in the crystal structure. The FePO4-coated sample exhibits both improved initial discharge capacity and columbic efficiency compared to the pristine one. More significantly, the FePO4 coating layer has a much positive influence on the cycling perfor- mance. The FePO4-coated sample exhibits capacity reten- tion of 82 % after 100 cycles at 0.5℃ between 2.0 and 4.8 V, while only 28 % for the pristine one at the same charge-discharge condition. The electrochemical impe- dance spectroscopy （EIS） results indicate that this improved cycling performance could be ascribed to the presence of FePO4 on the surface of Li[Li0.2Ni0.13Co0.13Mno.54102 par- ticle, which helps to protect the cathode from chemical attacks by HF and thus suppresses the large increase in charge transfer resistance.

Integration of GaN thin films with silicon substrates by fusion bonding and laser lift-off

GaN thin films grown on sapphire substrates by metalorganic chemical vapor deposition （MOCVD） are successfully bonded and transferred onto Si receptor substrates using fusion bonding and laser lift-off （LLO） technique. GaN/Al2O3 structures are joined to Si substrates by pressure bonding Ti/Au coated GaN surface onto Ti/Au coated Si receptor substrates at the temperature of 400℃. KrF excimer laser with 400-mJ/cm^2 energy density, 248-nm wavelength, and 30-ns pulse width is used to irradiate the wafer through the transparent sapphire substrates and separate GaN films from sapphire. Cross-section scanning electron microscopy （SEM） combined with energy dispersive X-ray spectrometer （EDS） measurements show that Au/Si solid solution is formed during bonding process. Atomic force microscopy （AFM） and photoluminescence （PL） measurements show that the qualities of GaN films on Si substrates degrade little after substrates transfer.

Study on the laser treatment of electroless Ni-P-SiC composite coatings

Effect of the laser treatment on electroless Ni-P-SiC composite coatings was investigated. The microscopic structure, surface morphology, ingredient, and performance of the Ni-P-SiC composite coatings were synthetically analyzed by the use of X-ray diffraction apparatus, scanning electron microscope, energy distribution spectrometer, micro-hardness tester, wear tester and so on. It was found that the composite coatings did make crystalloblastic transformation after laser heating. Structural analysis confirmed that some new types of phase Ni2Si or Ni3Si compound would emerge in the Ni-P-SiC coatings after laser treatment. The micro-hardness measurement results showed that when the laser power was 450 W with scanning speed of 0.5 m/min, the hardness of the coating was superior to the coating obtained by the conventional furnace heating, and wear resistance of the composite coating after laser treating could also improve.