Energy Dispersive X-ray Spectroscopy Studies Research Articles

Enhanced multiferroic properties in (1–y)BiFeO3–yNi0.50Cu0.05Zn0.45Fe2O4 composites

Multiferroic composites (1–y)BiFeO3–yNi0.50Cu0.05Zn0.45Fe2O4 (y=0.0, 0.1, 0.2, 0.3 and 0.4) are synthesized by the standard solid state reaction method. The X-ray diffraction analysis affirms the formation of both the component phases and also reveals that there is no chemical reaction between them. From the energy-dispersive X-ray spectroscopy study it is observed that the percentage of the elements in the component phases is well consistent with the nominal composition of the composites. Field Emission Scanning Electron Microscopy analysis shows almost homogeneous mixture of the two phases. The real part of the initial permeability increases (up to 67%) and the loss decreases with the ferrite content in the composites which is important in application point of view. Dielectric constant (ε′), loss tangent and AC conductivity are measured as a function of frequency at room temperature. The highest ε′ is obtained for 0.6BiFeO3–0.4Ni0.50Cu0.05Zn0.45Fe2O4 composite. The dielectric dispersion at lower frequency (<105Hz) is due to the interfacial polarization. The complex impedance spectroscopy is used to correlate between the electrical properties of the studied samples with their microstructures. Two semicircular arcs corresponding to both grain and grain boundary contribution to electrical properties have been observed in all the studied samples. The maximum magnetoelectric voltage coefficient is found to be ∼38mVcm−1Oe−1 for the composite with 80% ferroelectric+20% ferrite phases. The present composite might be a promising candidate as multiferroic materials showing effective electric and magnetic properties.

Adsorptive removal of cobalt ions on raw and alkali-treated lemon peels

Batch-wise biosorption of Co(II) from aqueous cobalt nitrate solution of different concentrations has been carried out on raw and NaOH-treated lemon peels. They were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, thermogravimetric analysis and Brunauer–Emmett–Teller surface area analysis. The influence of biosorbent dose, pH, contact time and temperature on the adsorption process has been studied. Maximum adsorption was observed at pH 6. The equilibrium adsorption on raw and NaOH-treated lemon peels was achieved in 150 and 210 min, the maximum adsorption capacity being 20.83 and 35.71 mg/g, respectively. Energy-dispersive X-ray spectroscopy and desorption study confirmed that the mechanism of adsorption is ion exchange. The Langmuir isotherm and pseudosecond-order kinetic model gave the best fit for the adsorption of Co(II). The desorption was found to be more than 96 % using 0.1 N HCl, and the adsorbent could be reused three times with intermediate alkaline regeneration stage. Experiments to establish the effect of competing metal ions on biosorption capacity were also performed. Thus, NaOH-treated lemon peels have shown the potential as a good biosorbent for treating industrial wastewater at low cobalt concentration.

AlN/SiO2/Si3N4/Si(100)-Based CMOS Compatible Surface Acoustic Wave Filter With −12.8-dB Minimum Insertion Loss

A CMOS compatible AlN/SiO2/Si3N4/Si(100) surface acoustic wave (SAW) device has been fabricated and will be compared with standard AlN/SiO2-based devices. The presented filter demonstrates high potential for CMOS integrated high-frequency SAW devices. The filter insertion loss could be improved to −12.8 dB. The device exhibits high crosstalk suppression of −50 dB on a standard Si-substrate (10 $\Omega $ cm). X-ray diffraction, (scanning) transmission electron microscopy, and energy dispersive X-ray spectroscopy studies correlate the signal quality with $c$ -axis orientation of aluminum nitride films on interdigitated transducer finger electrodes. Finite-element method simulations are in good agreement with the electric measurements and show typical Rayleigh particle displacement.

Model free Multiple Heating Rate Degradation Kinetic Studies of Modified Celluloses

The present paper depicts about the synthesis of cellulose ethyl ammonium thiophosphate (CEASP) and its metal complexes with Cd, Mo and Ce. CEASP and its metal complexes have been characterized by infrared (IR), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDXS) studies. The surface morphology of samples has been premeditated by means of scanning electron microscopy (SEM). The thermal studies of samples have been carried out at multiple heating rates 2, 5, 10 and 20 °C min -1 from ambient to 700 °C in nitrogen atmosphere. Non- isothermal model free kinetic methods have been used to calculate activation energy of samples i.e. Friedman, Ozawa-Flynn-Wall (O-F-W) and modified Coats- Redfern. The activation energy of samples lie in range 72-282 kJ mol -1 . Thermal study shows that initial degradation temperature of CEASP and its metal complexes decreases and there is abrupt increase in char yield of synthesized samples as compared to pure cellulose. These and other related information suggest that such type of derivatisation could be proved a good flame retardant for cellulose.

Indium Antimonide Nanoparticles Synthesized using Inert Gas Condensation Technique.

ABSTRACTNanoparticles (NPs) of Indium Antimonide (InSb) were synthesized using a vapor phase synthesis technique known as Inert Gas Condensation. NPs were directly deposited, at room temperature and under high vacuum, on glass cover slides, TEM grid, 1 inch-square (111) p-type Silicon wafer and Sodium Chloride substrates. XRD study revealed the crystalline behavior of these NPs exhibiting a cubic symmetry with preferred growth direction of (111). The average grain size of the NPs obtained using XRD results and the Debye-Scherrer formula was 25.62 nm. TEM studies showed a bimodal distribution of NPs with average NPs size of 13.70 and 33.20 nm. These values are consistent with the value obtained using XRD. 1:1 composition ratio of In:Sb was confirmed by the Energy Dispersive X-Ray Spectroscopy studies. The band gap of the NPs obtained using Fourier Transform Infrared (FTIR) spectroscopy was 0.413 eV at 300 K, which indicates quantum confinement in the band structure of these NPs.

High performance nanostructured Cr-WS&lt;SUB align="right"&gt;2 solid lubricant coatings prepared on mechanically textured substrates

Cr-WS2 nanocomposite solid lubricant coatings were prepared on mechanically textured stainless steel substrates. Micron-sized dimples of approximately 10-12 µm depth and 100 × 80 µm2 area with uniform dimple spacing of 300 µm were created on the substrates using a knurling tool. Substrate surface texturing improved the tribological properties of Cr-WS2 nanocomposite coatings significantly. Cr-WS2 nanocomposite coatings prepared on textured steel substrates exhibited a friction coefficient of 0.1 after 28,800 cycles compared to coatings prepared on non-textured substrates which exhibited a friction coefficient of 0.45. The dimpled regions acted as solid lubricant reservoirs and also helped in trapping wear debris. The retention of solid lubricant material in the dimpled region was confirmed using field emission scanning electron microscopy and energy dispersive X-ray spectroscopy studies.

Formation of Ag/Al Screen-Printing Contacts on B Emitters

In this study, the contact formation process of Al containing Ag screen-printing pastes to BBr3-based B emitters on Si is investigated. Therefore, a detailed scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy study of top-view and cross-sectional samples was conducted. The possible influence of a SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> :H antireflection coating was considered by comparing contacts with and without a SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> :H layer. To analyze the role of the glass frit in the paste, the contact formation of pastes without glass was examined. The results indicate that the Ag/Al contact spots grow below the Si surface/SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> :H layer. The glass frit is only indispensable for etching the antireflection layer-it is not needed for melting the metal in the screen-printing paste. The realized experiments lead to a phenomenological model for the contact formation process of Al containing screen-printing pastes to boron emitters.

Fabrication of a Superhydrophobic Al2O3 Surface Using Picosecond Laser Pulses

Ultrashort pulse laser (USPL) machining/structuring is a promising technique to create a micropattern on a material surface with very low distortion to the peripheral area or high precession. Thin sheets of alumina (Al2O3) are micromachined with ultraviolet laser pulses of 6.7 ps, to create a superhydrophobic surface by single-step processing. USPL patterned micropillars and microholes have been fabricated with a range of pulses varying from 100 to 1200 pulses/unit area. The impact of the number of pulses/unit area with respect to the geometry and static contact angle measurements has been studied. The surface is free from cracks, and the melting effect is well-pronounced for the blind microhole structures. An energy dispersive X-ray spectroscopy study revealed a marginal change in the elemental composition of the laser-patterned surface. The results show that the geometry of the laser-machined pattern plays a major role in changing the wetting properties rather than the chemical changes induced on the surface. The micropillars exhibited a consistent superhydrophobic surface with a static contact angle measurement of 150° ± 3°.

Local material composite sintered systems for fluoride removal

The article elaborates the development of gravity-based water filtration systems capable of removing fluoride using natural organic material. In this study, the precipitation and dissolution reaction occurring in suspension of hydroxyapatite (HAP) as addition of fluoride were investigated under well-defined condition. This process is set to occur in a quasi-static gravity-based water filter system. This system is a (pond sand, organic material (gaur seed powder, neem, sesame sawdust, and Ayurvedic waste), water, and HAP mixture) composite ceramic. This article illustrates these ceramic material systems manufactured using distinct permutations of pond sand and organic materials. HAP is introduced into the composite mix of pond sand and organic materials to manufacture some of the sintered ceramic filtration material systems tested here. The fluoride removal efficiency of these variant systems is discussed. The energy dispersive X-ray spectroscopy studies of the ceramics provided the mineral content within the system variants. At high temperatures beyond 600°C, the sintered hydroxyapatite is observed to have a microstructural transformation from amorphous to crystalline. The surface properties of these sintered as well as raw materials used in the production of the ceramic composite are also investigated. A mathematical multivariate regression model is derived providing a relationship between the effectiveness of the water filtration systems as a function of the raw material composition and properties. The Ayurvedic waste material was found to be a good substitute for HAP for fluoride removal. The proposed treatment system is appropriate and suitable approach for fluoride removal in rural areas, because of its simplicity and easy operation and handling. Since Ayurvedic and organic waste materials are easily available at low cost, the proposed method is very suitable for the people living in low-income rural areas of developing countries like India.

Bio-nanogate controlled enzymatic reaction for virus sensing.

The objective of this study was to develop an aptamer-based bifunctional bio-nanogate, which could selectively respond to target molecules, and control enzymatic reaction for electrochemical measurements. It was successfully applied for sensitive, selective, rapid, quantitative, and label-free detection of avian influenza viruses (AIV) H5N1. A nanoporous gold film with pore size of ~20 nm was prepared by a metallic corrosion method, and the purity was checked by energy-dispersive X-ray spectroscopy (EDS) study. To improve the performance of the bio-nanogate biosensor, its main analytical parameters were studied and optimized. We demonstrated that the developed bio-nanogate was capable of controlling enzymatic reaction for AIV H5N1 sensing within 1h with a detection limit of 2(-9)HAU (hemagglutination units). The enzymatic reaction was able to cause significant current change due to the presence of target AIV. A linear relationship was found in the virus titer range of 2(-10)-2(2)HAU. No interference was observed from non-target AIV subtypes such as H1N1, H2N2, H4N8 and H7N2. The developed approach could be adopted for sensing of other viruses.

Polyethylene glycol-assisted growth of Cu2SnS3 promising absorbers for thin film solar cell applications

In this paper, we report, for the first time, the results of the polyethylene glycol- (PEG) assisted preparation and characterization of high-quality and well-crystallized Cu2SnS3 (CTS) thin films obtained using sol–gel spin-coating method and a subsequent annealing in a sulphur atmosphere. Structural, morphological, compositional, electrical and optical investigations were carried out. The X-ray diffraction patterns of the samples proved the polycrystalline nature and preferred crystallization of the films. No peak referring to other binary or ternary phases were detected in the patterns. The intensity of the preferred orientation and crystallite size of the films increased with increasing PEG content. This trend yielded an improvement in photo-transient currents of the PEG-assisted growth of CTS films. The scanning electron microscopy images revealed that the CTS films have continuous, dense and agglomeration-like morphology. Through energy dispersive X-ray spectroscopy studies, it has been deduced that the samples consist of Cu, Sn and S of which atomic percentages were consistent with Cu/Sn and S/metal initial ratios. The agglomerated morphology of the samples has been attributed to increasing PEG content. A remarkable enhancement was observed in photo-transient currents of p-n junction of the produced films along with increasing PEG content. Through resistivity-temperature measurements, three impurity level electrical activation energy values for each film were found. Optical band gap values of the films were estimated via absorbance-wavelength behaviours and decreased with increasing PEG content. It has been revealed that PEG-assisted growth of CTS thin films is a promising way to improve its photovoltaic characteristics.

Immobilization of glucose oxidase on graphene and cobalt phthalocyanine composite and its application for the determination of glucose

We described a simple and facile chemical reduction strategy for the preparation of graphene (GR)-cobalt phthalocyanine (CoPc) composite and explored it for the enzymatic determination of glucose. CoPc is an active mediator and electrocatalysts for the immobilization of GOx and determination of glucose. However, it is not stable on the electrode surface and also suffers from lack of conductivity. Here, we have employed GR as the suitable support to stabilize CoPc through simple chemical reduction method and the resulting composite has been used for the glucose biosensor application. Scanning electron microscopy, X-ray diffraction and Energy-dispersive X-ray spectroscopy studies confirmed the successful formation of composite. Direct electron transfer of glucose oxidase (GOx) was observed with well defined redox peaks at the formal potential of −0.44V. The amount of electroactive GOx (Г) and electron transfer rate constant (ks) were calculated to be 3.77×10−10molcm−2 and 3.57s−1, respectively. The fabricated amperometric biosensor detects glucose in wide linear concentration range from 10μM to 14.8mM with high sensitivity of 5.09μAmM−1cm−2. The sensor offered very low detection limit (LOD) of 1.6μM. In addition, practical feasibility of the sensor has been explored in screen printing carbon electrode with accurate determination of glucose present in human blood serum and urine samples. Furthermore, the sensor exhibited appreciable stability, repeatability and reproducibility results.

Surface morphology and optical properties of PVA/PbS nanoparticles

PVA capped lead sulfide (PbS) nanoparticles were successfully synthesized by the simple wet chemical method. The synthesized product has been characterized by powder X-ray diffraction (XRD), UV–vis spectrophotometry, FTIR spectroscopy, scanning electron microscopy (SEM), transmission electron Microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and photoluminescence studies. The size of the PVA capped PbS nanoparticles was determined From XRD and it is found that the size of the particles of the order of 42–5nm. FTIR and EDX analyses are used to identify the presence of organic molecules and elements in the synthesized PbS nanoparticles. Significant “blue-shift” from bulk material was observed on the PbS nanoparticles using UV–vis spectra.A 10-fold increase in photoluminescence intensity is reached at 4g PVA addition.

Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy Studies on Processed Tooth Graft Material by Vacuum-ultrasonic Acceleration.

Purpose:The current gold standard for clinical jawbone formation involves autogenous bone as a graft material. In addition, demineralized dentin can be an effective graft material. Although demineralized dentin readily induces heterotopic bone formation, conventional decalcification takes three to five days, so, immediate bone grafting after extraction is impossible. This study evaluated the effect of vacuum ultrasonic power on the demineralization and processing of autogenous tooth material and documented the clinical results of rapidly processed autogenous demineralized dentin (ADD) in an alveolar defects patient.Methods:The method involves the demineralization of extracted teeth with detached soft tissues and pulp in 0.6 N HCl for 90 minutes using a heat controlled vacuum-ultrasonic accelerator. The characteristics of processed teeth were evaluated by scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Bone grafting using ADD was performed for narrow ridges augmentation in the mandibular area.Results:The new processing method was completed within two hours regardless of form (powder or block). EDS and SEM uniformly demineralized autotooth biomaterial. After six months, bone remodeling was observed in augmented sites and histological examination showed that ADD particles were well united with new bone. No unusual complications were encountered.Conclusion:This study demonstrates the possibility of preparing autogenous tooth graft materials within two hours, allowing immediate one-day grafting after extraction.

Highly stable and sensitive amperometric sensor for the determination of trace level hydrazine at cross linked pectin stabilized gold nanoparticles decorated graphene nanosheets

Herein, we have described a simple electrochemical method for the deposition of the calcium ions cross linked pectin film (CCLP) along with gold nanoparticles (GNPs) on the graphene (GR) modified glassy carbon electrode (GCE) and applied for the determination of hydrazine. The formation of composite film was confirmed by cyclic voltammetry, scanning electron microscopy, Energy-Dispersive X-ray spectroscopy and X-ray diffraction studies. The GR/CCLP-GNPs/GCE film exhibited significantly enhanced electro catalytic ability towards oxidation of hydrazine. The kinetic parameters such as electron transfer coefficient (α) and diffusion coefficient (Do) for the hydrazine oxidation were determined as 0.46 and 2.91×10−6 cm2 s−1, respectively. Two linear ranges were observed in the amperometric determination of hydrazine: (1) 10–600nM with sensitivity of 47.6 nAnM−1cm−2 and (2) 0.6–197.4μM with sensitivity of 1.786μAμM−1cm−2. The sensor is able to detect trace level of hydrazine in nanomolar range with very low deletion limit (LOD) of 1.6nM. This is the lowest LOD achieved compare to all the reported electrochemical amperometric sensors so far. In addition, the sensor is able to detect hydrazine even in the presence of 500 folds excess quantity of interfering ions present in the water and biological liquid. The practicality of the proposed sensor has been demonstrated in water and urine samples. Other advantages of the sensor are repeatability, reproducibility and stability.

Green synthesis of silver and gold nanoparticles using Zingiber officinale root extract and antibacterial activity of silver nanoparticles against food pathogens.

In the present study, we synthesized silver and gold nanoparticles with a particle size of 10-20nm, using Zingiber officinale root extract as a reducing and capping agent. Chloroauric acid (HAuCl4) and silver nitrate (AgNO3) were mixed with Z. officinale root extract for the production of silver (AgNPs) and gold nanoparticles (AuNPs). The surface plasmon absorbance spectra of AgNPs and AuNPs were observed at 436-531nm, respectively. Optimum nanoparticle production was achieved at pH 8 and 9, 1mM metal ion, a reaction temperature 50°C and reaction time of 150-180min for AgNPs and AuNPs, respectively. An energy-dispersive X-ray spectroscopy (SEM-EDS) study provides proof for the purity of AgNPs and AuNPs. Transmission electron microscopy images show the diameter of well-dispersed AgNPs (10-20nm) and AuNPs (5-20nm). The nanocrystalline phase of Ag and Au with FCC crystal structures have been confirmed by X-ray diffraction analysis. Fourier transform infrared spectroscopy analysis shows the respective peaks for the potential biomolecules in the ginger rhizome extract, which are responsible for the reduction in metal ions and synthesized AgNPs and AuNPs. In addition, the synthesized AgNPs showed a moderate antibacterial activity against bacterial food pathogens.

Influence of atomic oxygen exposure on surface resistivity of silicon doped polyimide affecting spacecraft charging

In the present research work, the vulnerability of silicon doped polyimide by atomic oxygen present in LEO (lower earth orbit) of space was investigated. AO-exposure of a fluence of 5.4 × 1018 atoms cm−2 significantly changed the surface resistivity properties of polyimide which is a prime factor governing spacecraft surface charging problem. This amount of fluence affected surface morphology and eroded the surface thickness as observed by SEM (scanning electron microscopy), laser beam imaging and surface profilometer study. This much exposure also increased the oxygen and silicon content on the surface as observed by XPS (X-ray photoelectron spectroscopy) and EDX (Energy-dispersive X-ray spectroscopy) study.

Reversible in situ precipitation: a flow-through approach for coating macroporous supports with metal hydroxides

In this study we report on the production of metal-hydroxide-coated macroporous polymers (MHCMPs), which mainly involves a polyacrylamide backbone coated with iron–aluminium double hydroxides. The coating process is fast, occurs using relatively mild reagents at room temperature, and can be repeated multiple times, thus making it a very simple and flexible process. Electron microscopy and energy dispersive X-ray spectroscopy studies showed that metal hydroxide coating occurred throughout the polymer backbone. It was shown that the mass of metal hydroxides incorporated in the MHCMPs could be adjusted by varying the initial salt solution concentration or the number of cycles in the process. Under the studied conditions, on a polymer backbone of mass 25 mg, we observed a maximum metal hydroxide mass incorporation of 18 mg for the MHCMPs produced at 6 cycles by using 0.4 M iron and aluminium salt solution. Nitrogen adsorption isotherms indicated that the surface area of the MHCMPs increased linearly with the increase in the mass of metal hydroxides incorporated. The polymer backbone with no mass incorporated showed a BET surface area of 18 m2 g−1 and the MHCMPs with maximum mass incorporation under the studied conditions showed a BET surface area of 63 m2 g−1. MHCMPs with varying mass incorporations were applied for arsenic (As(III)) adsorption and showed a high As(III) removal, indicating that they can serve as potential adsorbents. In addition, MHCMPs incorporated with other metal hydroxides were also produced and characterized to show that this method is applicable for coating these as well.

Electrochemical characterization of Ni-Co and Ni-Co-Fe for oxidation of methyl alcohol fuel with high energetic catalytic surface

Non Pt based metals and alloys as electrode materials for methyl alcohol fuel cells have been investigated with an aim of finding high electrocatalytic surface property for the faster electrode reactions. Electrodes were fabricated by electrodeposition on pure Al foil, from an electrolyte of Ni, Co, Fe salts. The optimum condition of electrodeposition were found out by a series of experiments, varying the chemistry of the electrolyte, pH value, temperature, current and cell potential. Polarization study of the coated Ni-Co or Ni-Co-Fe alloy on pure Al was found to exhibit high exchange current density, indicating an improved electro catalytic surface with faster charge- discharge reactions at anode and cathode and low overvoltage. Electrochemical impedance studies on coated and uncoated surface clearly showed that the polarization resistance and impedance were decreased by Ni-Co or N-Co-Fe coating. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and atomic absorption spectroscopy (AAS) studies confirmed the presence of alloying elements and constituents of the alloy. The morphology of the deposits from scanning electron microscope (SEM) images indicated that the electrode surface was a three dimensional space which increased the effective surface area for the electrode reactions to take place.

Hydrothermal synthesis of wurtzite Zn1−xNixS mesoporous nanospheres: With blue–green emissions and ferromagnetic Curie point above room temperature

Wurtzite Zn1−xNixS (x=0.00, 0.01, 0.02, 0.03, 0.04 and 0.05) mesoporous nanospheres were successfully synthesized via a versatile hydrothermal method with the assistance of ethylenediamine (EN). The as synthesized nanospheres were uniform, mono-dispersed with a spherical shape. Microstructure investigations revealed that these nanospheres were mesoporous clusters of Zn1−xNixS nanoparticles with the size around 5nm. X-ray Diffraction, X-ray photoelectron spectroscopy, and Energy-dispersive X-ray spectroscopy studies confirmed that the Ni ions substituted into ZnS host lattice without altering the crystal structure. The Fourier-transform infrared spectra confirmed the coupling between the EN molecules and ZnS. The absorption edge in the diffuse reflection spectra shifted towards lower wavelength with increasing Ni concentration, indicating an expansion in the band gap energy that is estimated to be in the range of 3.53–3.60eV. The photoluminescence spectra of the doped and un-doped samples contained a broad emission band covering the range of 350–650nm. Room temperature magnetization studies indicated that the undoped ZnS nanospheres yielded only diamagnetism, whereas the doped samples exhibited ferromagnetism that can be attributed to the Ni2+ dopants. The temperature dependence of magnetization revealed that the Zn1−xNixS nanospheres have Curie point above room temperature. The intrinsic ferromagnetism and ferromagnetic Curie point above room temperature promise a great deal of potential applications in spintronic devices for Zn1−xNixS nanospheres.