Search results for: continuous electron diffraction tomography

Authors: K. Abbas, R. Ahmad, I. A. Khan, S. Saleem, U. Ikhlaq

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Nitriding of p-type Si samples by pulsed DC glow discharge is carried out for different Ar concentrations (30% to 90%) in nitrogen-argon plasma whereas the other parameters like pressure (2 mbar), treatment time (4 hr) and power (175 W) are kept constant. The phase identification, crystal structure, crystallinity, chemical composition, surface morphology and topography of the nitrided layer are studied using X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR), optical microscopy (OM), scanning electron microscopy (SEM) and atomic force microscopy (AFM) respectively. The XRD patterns reveal the development of different diffraction planes of Si₃N₄ confirming the formation of polycrystalline layer. FTIR spectrum confirms the formation of bond between Si and N. Results reveal that addition of Ar into N₂ plasma plays an important role to enhance the production of active species which facilitate the nitrogen diffusion.

Keywords: crystallinity, glow discharge, nitriding, sputtering

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Authors: Darlington Ashiegbu, Herman Johannes Potgieter

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The increasing utilization of Zinc Oxide (ZnO) as a better alternative to TiO₂ has been attributed to its wide bandgap (3.37eV), lower production cost, ability to absorb over a larger range of the UV-spectrum and higher efficiency in some cases. ZnO nanoparticles were synthesized via sol-gel process and calcined at 400ᵒC, 500ᵒC, and 650ᵒC. The as-synthesized nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and Brunauer–Emmett–Teller (BET) surface area measurement. Scanning electron micrograph revealed pseudo-spherical and rod-like morphologies and a high rate of agglomeration for the sample calcined at 650ᵒC, Brunnauer Emmett Teller (BET) surface area measurement was highest in the sample calcined at 500ᵒC, energy dispersive X-ray spectroscopy (EDS) results confirmed the purity of the samples as only Zn and O₂ were detected and X-ray diffraction (XRD) results revealed crystalline hexagonal wurtzite structure of the ZnO nanoparticles. All three samples were utilized in the degradation of ethylbenzene, and a UV-Vis spectrophotometer was utilized in monitoring degradation of ethylbenzene. The sample calcined at 500ᵒC had the highest surface area for reaction, lowest agglomeration and the highest photocatalytic activity in the degradation of ethylbenzene. This revealed temperature as a very important factor in improved and higher photocatalytic activity.

Keywords: ethylbenzene, pseudo-spherical, sol-gel, zinc oxide

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Authors: Santanu Pakhira, Chandan Mazumdar, R. Ranganathan, Maxim Avdeev

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Magnetically frustrated systems are of great interest and one of the most adorable topics for the researcher of condensed matter physics, due to their various interesting properties, viz. ground state degeneracy, finite entropy at zero temperature, lowering of ordering temperature, etc. Ternary intermetallics with the composition RE₂TX₃ (RE = rare-earth element, T= d electron transition metal and X= p electron element) crystallize in hexagonal AlB₂ type crystal structure (space group P6/mmm). In a hexagonal crystal structure with the antiferromagnetic interaction between the moments, the center moment is geometrically frustrated. Magnetic frustration along with disorder arrangements of non-magnetic ions are the building blocks for metastable spin-glass ground state formation for most of the compounds of this stoichiometry. The newly synthesized compound Er₂NiSi₃ compound forms in single phase in AlB₂ type structure with space group P6/mmm. The compound orders antiferromagnetically below 5.4 K and spin freezing of the frustrated magnetic moments occurs below 3 K for the compound. The compound shows magnetic relaxation behavior and magnetic memory effect below its freezing temperature. Neutron diffraction patterns for temperatures below the spin freezing temperature have been analyzed using FULLPROF software package. Diffuse magnetic scattering at low temperatures yields spin glass state formation for the compound.

Keywords: antiferromagnetism, magnetic frustration, spin-glass, neutron diffraction

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Authors: L. Gyansah, Yanfang Shen, Jiqiang Wang, Tianying Xiong

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SiCₚ/ pure Al composites with different SiC fractions (20 wt %, 30 wt %, and 40 wt %) were precisely cold sprayed, followed by hot axial-compression tests at deformation temperatures of 473 K to 673 K, leading to failure of specimens through routine crack propagation in their multiphase. The plastic deformation behaviour with respect to the SiCₚ contents and the deformation temperatures were studied at strain rate 1s-1.As-sprayed and post-failure specimens were analyzed by X-ray computed tomography (XCT), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Quasi-static thermomechanical testing results revealed that compressive strength (UTS = 228 MPa and 30.4 %) was the highest in the composites that was thermomechanically compressed at 473 K compared to those of the as-sprayed, while the as-sprayed exhibited a compressive strength of 182.8 MPa related to the increment in SiC fraction. Strength—plasticity synergy was promoted by dynamic recrystallization (DRX) through strengthening and refinement of the grains. The DRX degree depends relevantly on retainment of the uniformly ultrafine SiCₚ particulates, the pinning effects of the interfaces promoted by the ultrafine grain structures (UFG), and the higher deformation temperature. Reconstructed X-ray computed tomography data revealed different crack propagation mechanisms. A single-plane shear crack with multi-laminates fracture morphology yields relatively through the as-sprayed and as-deformed at 473 K deposits, while a multiphase plane shear cracks preeminently existed in high temperature deformed deposits resulting in multiphase-interface delaminations. Three pertinent strengthening mechanisms, videlicet, SiCp dispersed strengthening, refined grain strengthening, and dislocation strengthening, existed in the gradient microstructure, and their detailed contributions to the thermomechanical properties were discussed.

Keywords: cold spraying, hot deformation, deformation temperature, thermomechancal properties, SiC/Al composite

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Authors: Mohamed Khedr, Ahmed Farghali, Waleed El Rouby, Abdelrhman Hamdeldeen

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Pure CeO2, Sm and Gd doped CeO2 were successfully prepared via hydrothermal method. The effect of hydrothermal temperature, reaction time and precursors were investigated. The prepared nanoparticles were characterized using X-ray diffraction (XRD), FT-Raman Spectroscopy, transmission electron microscope (TEM) and field emission scanning electron microscope (FESEM). The prepared pure and doped CeO2 nanoparticles were used as photo-catalyst for the degradation of Methylene blue (MB) dye under UV light irradiation. The results showed that Gd doped CeO2 nano-particles have the best catalytic degradation effect for MB under UV irradiation. The degradation pathways of MB were followed using liquid chromatography (LC/MS) and it was found that Gd doped CeO2 was able to oxidize MB dye with a complete mineralization of carbon, nitrogen and sulfur heteroatoms into CO2, NH4+, NO3- and SO42-.

Keywords: CeO2, doped CeO2, photocatalysis, methylene blue

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Authors: Jorge Martinez-Garcia, Ingrid Stelzner, Joerg Stelzner, Damian Gwerder, Philipp Schuetz

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Tree-ring analysis is an important part of the quality assessment and the dating of (archaeological) wood samples. It provides quantitative data about the whole anatomical ring structure, which can be used, for example, to measure the impact of the fluctuating environment on the tree growth, for the dendrochronological analysis of archaeological wooden artefacts and to estimate the wood mechanical properties. Despite advances in computer vision and edge recognition algorithms, detection and counting of annual rings are still limited to 2D datasets and performed in most cases manually, which is a time consuming, tedious task and depends strongly on the operator’s experience. This work presents an image processing approach to detect the whole 3D tree-ring structure directly from X-ray computed tomography imaging data. The approach relies on a modified Canny edge detection algorithm, which captures fully connected tree-ring edges throughout the measured image stack and is validated on X-ray computed tomography data taken from six wood species.

Keywords: ring recognition, edge detection, X-ray computed tomography, dendrochronology

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Authors: Rinlee Butch M. Cervera, Princess Stephanie P. Llanos

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Lithium iron phosphate (LiFePO₄) is a potential cathode material for lithium-ion batteries due to its promising characteristics. In this study, pure LiFePO₄ (LFP) and carbon-coated nanograined LiFePO₄ (LFP-C) is synthesized and characterized for its microstructural properties. X-ray diffraction patterns of the synthesized samples can be indexed to an orthorhombic LFP structure with about 63 nm crystallite size as calculated by using Scherrer’s equation. Agglomerated particles that range from 200 nm to 300 nm are observed from scanning electron microscopy images. Transmission electron microscopy images confirm the crystalline structure of LFP and coating of amorphous carbon layer. Elemental mapping using energy dispersive spectroscopy analysis revealed the homogeneous dispersion of the compositional elements. In addition, galvanostatic charge and discharge measurements were investigated for the cathode performance of the synthesized LFP and LFP-C samples. The results showed that the carbon-coated sample demonstrated the highest capacity of about 140 mAhg^-1 as compared to non-coated and micrograined sized commercial LFP.

Keywords: ceramics, energy storage, electrochemical measurements, transmission electron microscope

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Authors: C. Fornacelli, P. Colomban, E. Mugnaioli, I. Memmi Turbanti

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When semiconductor particles are reduced in scale to nanometer dimension, their optical and electro-optical properties strongly differ from those of bulk crystals of the same composition. Since sampling is often not allowed concerning cultural heritage artefacts, the potentialities of two non-invasive techniques, such as Raman and Fiber Optic Reflectance Spectroscopy (FORS), have been investigated and the results of the analysis on some original glasses of different colours (from yellow to orange and deep red) and periods (from the second decade of the 20th century to present days) are reported in the present study. In order to evaluate the potentialities of the application of non-invasive techniques to the investigation of the structure and distribution of nanoparticles dispersed in a glass matrix, Scanning Electron Microscopy (SEM) and energy-disperse spectroscopy (EDS) mapping, together with Transmission Electron Microscopy (TEM) and Electron Diffraction Tomography (EDT) have also been used. Raman spectroscopy allows a fast and non-destructive measure of the quantum dots composition and size, thanks to the evaluation of the frequencies and the broadening/asymmetry of the LO phonons bands, respectively, though the important role of the compressive strain arising from the glass matrix and the possible diffusion of zinc from the matrix to the nanocrystals should be taken into account when considering the optical-phonons frequency values. The incorporation of Zn has been assumed by an upward shifting of the LO band related to the most abundant anion (S or Se), while the role of the surface phonons as well as the confinement-induced scattering by phonons with a non-zero wavevectors on the Raman peaks broadening has been verified. The optical band gap varies from 2.42 eV (pure CdS) to 1.70 eV (CdSe). For the compositional range between 0.5≤x≤0.2, the presence of two absorption edges has been related to the contribution of both pure CdS and the CdSxSe1-x solid solution; this particular feature is probably due to the presence of unaltered cubic zinc blende structures of CdS that is not taking part to the formation of the solid solution occurring only between hexagonal CdS and CdSe. Moreover, the band edge tailing originating from the disorder due to the formation of weak bonds and characterized by the Urbach edge energy has been studied and, together with the FWHM of the Raman signal, has been assumed as a good parameter to evaluate the degree of topological disorder. SEM-EDS mapping showed a peculiar distribution of the major constituents of the glass matrix (fluxes and stabilizers), especially concerning those samples where a layered structure has been assumed thanks to the spectroscopic study. Finally, TEM-EDS and EDT were used to get high-resolution information about nanocrystals (NCs) and heterogeneous glass layers. The presence of ZnO NCs (< 4 nm) dispersed in the matrix has been verified for most of the samples, while, for those samples where a disorder due to a more complex distribution of the size and/or composition of the NCs has been assumed, the TEM clearly verified most of the assumption made by the spectroscopic techniques.

Keywords: CdSxSe1-x, EDT, glass, spectroscopy, TEM-EDS

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Authors: Rashad Al-Gaashani, Muataz A. Atieh

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In this study, the effect of preparation temperature, namely room temperature (RT), 40, 60, and 85°C, on producing of high-quality graphene oxide (GO) has been investigated. GO samples have been prepared by chemical oxidation of graphite via a safe improved chemical technique using a blend of two deferent acids: sulphuric acid (H₂SO₄) and phosphoric acid (H₃PO₄) with volume ratio 4:1, respectively. potassium permanganate (KMnO₄) and hydrogen peroxide (H₂O₂) were applied as oxidizing agents. In this work, sodium nitrate (NaNO₃) was excluded, so the emission of hazardous explosive gases such as NO₂ and N₂O₂ was shunned. Ice and oil baths were used to carefully control the temperature. Several characterization instruments including X-Ray diffraction, transmission electron microscopy, scanning electron microscopy, electron dispersive spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and UV-vis spectroscopy were used to study and compare the synthesized samples. The results indicated that GO can be prepared at RT with graphite oxide, and the purity of GO increased with rising of the solvent temperature. Optical properties of GO samples were studied using UV-vis absorption spectra.

Keywords: chemical method, graphite, graphene oxide, optical properties

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Authors: Raphaelle Guillou, Matthieu Le Saux, Jean-Christophe Brachet, Thomas Guilbert, Elodie Rouesne, Denis Menut, Caroline Toffolon-Masclet, Dominique Thiaudiere

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In some hypothetical accidental situations, such as during a Loss Of Coolant Accident (LOCA) in pressurized water reactors, fuel cladding tubes made of zirconium alloys can be exposed for a few minutes to steam at High Temperature (HT up to 1200°C) before being cooled and then quenched in water. Under LOCA-like conditions, the cladding undergoes a number of metallurgical changes (phase transformations, oxygen diffusion and growth of an oxide layer...) and is consequently submitted to internal stresses whose state evolves during the transient. These stresses can have an effect on the oxide structure and the oxidation kinetics of the material. They evolve during cooling, owing to differences between the thermal expansion coefficients of the various phases and phase transformations of the metal and the oxide. These stresses may result in the failure of the cladding during quenching, once the material is embrittled by oxidation. In order to progress in the evaluation of these internal stresses, X-ray diffraction experiments were performed in-situ under synchrotron radiation during HT oxidation and subsequent cooling on Zircaloy-4 sheet samples. First, structural evolutions, such as phase transformations, have been studied as a function of temperature for both the oxide layer and the metallic substrate. Then, internal stresses generated within the material oxidized at temperatures between 700 and 900°C have been evaluated thanks to the 2θ diffraction peak position shift measured during the in-situ experiments. Electron backscatter diffraction (EBSD) analysis was performed on the samples after cooling in order to characterize their crystallographic texture. Furthermore, macroscopic strains induced by oxidation in the conditions investigated during the in-situ X-ray diffraction experiments were measured in-situ in a dilatometer.

Keywords: APRP, stains measurements, synchrotron diffraction, zirconium allows

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Authors: Ashwani Kumar Aggarwal

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NIR Light is non-ionizing and can pass easily through living tissues such as breast without any harmful effects. Therefore, use of NIR light for imaging the biological tissue and to quantify its optical properties is a good choice over other invasive methods. Optical tomography involves two steps. One is the forward problem and the other is the reconstruction problem. The forward problem consists of finding the measurements of transmitted light through the tissue from source to detector, given the spatial distribution of absorption and scattering properties. The second step is the reconstruction problem. In X-ray tomography, there is standard method for reconstruction called filtered back projection method or the algebraic reconstruction methods. But this method cannot be applied as such, in optical tomography due to highly scattering nature of biological tissue. A hybrid algorithm for reconstruction has been implemented in this work which takes into account the highly scattered path taken by photons while back projecting the forward data obtained during Monte Carlo simulation. The reconstructed image suffers from blurring due to point spread function. This blurred reconstructed image has been enhanced using a digital filter which is optimal in mean square sense.

Keywords: least-squares optimization, filtering, tomography, laser interaction, light scattering

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Authors: Ogunniran Kehinde Olurotimi, Adekoya Joseph, Ehi-Eromosele Cyril, Mehdi Shihab, Mesubi Adediran, Tadigoppula Narender

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Nicotinic acid hydrazide and 2,4-dihydoxylbenzaldehyde were condensed at 20°C to form an acylhydrazone (H3L) with ONO coordination pattern. The structure of the acylhydrazone was elucidated by using CHN analyzer, ESI mass spectrometry, IR, 1H NMR, 13C NMR and 2D NMR such as COSY and HSQC. Thereafter, five novel metal complexes [Mn(II), Fe(II), Pt(II) Zn(II) and Pd(II)] of the hydrazone ligand were synthesized and their structural characterization were achieved by several physicochemical methods, namely elemental analysis, electronic spectra, infrared, EPR, molar conductivity and powder X-ray diffraction studies. Structural geometries of some of the compounds were supported by using Hyper Chem-8 program for the molecular mechanics and semi-empirical calculations. The stability energy (E) and electron potentials (eV) for the frontier molecules were calculated by using PM3 method. An octahedral geometry was suggested for both Pd(II) and Zn(II) complexes while both Mn(II) and Fe(II) complexes conformed with tetrahedral pyramidal. However, Pt(II) complex agreed with tetrahedral geometry. In vitro antitubercular activity study of the ligand and the metal complexes were evaluated against Mycobacterium tuberculosis, H37Rv, by using micro-diluted method. The results obtained revealed that (PtL1) (MIC = 0.56 µg/mL), (ZnL1) (MIC = 0.61 µg/mL), (MnL1) (MIC = 0.71 µg/mL) and (FeL1) (MIC = 0.82 µg/mL), exhibited a significant activity when compared with first line drugs such as isoniazid (INH) (MIC = 0.9 µg/mL). H3L1 exhibited lesser antitubercular activity with MIC value of 1.02 µg/mL. However, the metal complexes displayed higher cytoxicity but were found to be non-significant different (P ˂ 0.05) to isoniazid drug.

Keywords: hydrazones, electron spin resonance, thermogravimetric, powder X-ray diffraction, antitubercular agents

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Authors: Noureddine Benharkat, Abdelkader Chouaih, Nourdine Boukabcha

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A thiourea derivative compound was synthesized and subjected to structural analysis using single-crystal X-ray diffraction (XRD). The crystallographic data unveiled its crystallization in the P21/c space group within the monoclinic system. Examination of the dihedral angles indicated a notable non-planar structure. To support and interpret these resulats, density functional theory (DFT) calculations were conducted utilizing the B3LYP functional along with a 6–311 G (d, p) basis set. Additionally, to assess the contribution of intermolecular interactions, Hirshfeld surface analysis and 2D fingerprint plots were employed. Various types of interactions, whether weak intramolecular or intermolecular, within a molecule can significantly impact its stability. The distinctive signature of non-covalent interactions can be detected solely through electron density analysis. The NCI-RDG analysis was employed to investigate both repulsive and attractive van der Waals interactions while also calculating the energies associated with intermolecular interactions and their characteristics. Additionally, a molecular docking study was studied to explain the structure-activity relationship, revealing that the title compound exhibited an affinity energy of -6.8 kcal/mol when docked with B-DNA (1BNA).

Keywords: computational chemistry, density functional theory, crystallography, molecular docking, molecular structure, powder x-ray diffraction, single crystal x-ray diffraction

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Authors: A. Maruf Aytekin

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We present our approach on using continuous delivery pattern for release management. One of the key practices of agile and lean teams is the continuous delivery of new features to stakeholders. The main benefits of this approach lie in the ability to release new applications rapidly which has real strategic impact on the competitive advantage of an organization. Organizations that successfully implement Continuous Delivery have the ability to evolve rapidly to support innovation, provide stable and reliable software in more efficient ways, decrease the amount of resources need for maintenance, and lower the software delivery time and costs. One of the objectives of this paper is to elaborate a case study where IT division of Central Securities Depository Institution (MKK) of Turkey apply Continuous Delivery pattern to improve release management process.

Keywords: automation, continuous delivery, deployment, release management

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Authors: Aswin Kumar Krishnan, Yat Choy Wong, Reiza Mukhlis, Zipeng Zhang, Arul Arulrajah

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The continuous increase in vehicle uptake escalates the number of rubber tyre waste which need to be managed to avoid landfilling and stockpiling. The present research focused on the sustainable use of rubber crumbs in clay roof tiles. The properties of roof tiles composed of clay, rubber crumbs, NaOH, and Na₂SiO₃ with a 10% alkaline activator were studied. Tile samples were fabricated by heating the compacted mixtures at 50°C for 72 hours, followed by a higher heating temperature of 200°C for 24 hours. The effect of rubber crumbs aggregates as a substitution for the raw clay materials was investigated by varying their concentration from 0% to 2.5%. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses have been conducted to study the phases and microstructures of the samples. It was found that the optimum rubber crumbs concentration was at 0.5% and 1%, while cracks and larger porosity were found at higher crumbs concentrations. Water absorption and compressive strength test results demonstrated that rubber crumbs and clay satisfied the standard requirement for the roof tiles.

Keywords: rubber crumbs, clay, roof tiles, alkaline activators

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Authors: Anju Joshi, C. N. Tharamani

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Diabetes is one of the leading cause of death at present and remains an important concern as the prevalence of the disease is increasing at an alarming rate. Therefore, it is crucial to diagnose the accurate levels of glucose for developing an efficient therapeutic for diabetes. Due to the availability of convenient and compact self-testing, continuous monitoring of glucose is feasible nowadays. Enzyme based electrochemical sensing of glucose is quite popular because of its high selectivity but suffers from drawbacks like complicated purification and immobilization procedures, denaturation, high cost, and low sensitivity due to indirect electron transfer. Hence, designing a robust enzyme free platform using transition metal oxides remains crucial for the efficient and sensitive determination of glucose. In the present work, manganese doped nickel oxide nanoparticles (Mn-NiO) has been synthesized onto the surface of multiwalled carbon nanotubes using a simple microwave assisted approach for non-enzymatic electrochemical sensing of glucose. The morphology and structure of the synthesized nanostructures were characterized using scanning electron microscopy (SEM) and X-Ray diffraction (XRD). We demonstrate that the synthesized nanostructures show enormous potential for electrocatalytic oxidation of glucose with high sensitivity and selectivity. Cyclic voltammetry and square wave voltammetry studies suggest superior sensitivity and selectivity of Mn-NiO decorated carbon nanotubes towards the non-enzymatic determination of glucose. A linear response between the peak current and the concentration of glucose has been found to be in the concentration range of 0.01 μM- 10000 μM which suggests the potential efficacy of Mn-NiO decorated carbon nanotubes for sensitive determination of glucose.

Keywords: diabetes, glucose, Mn-NiO decorated carbon nanotubes, non-enzymatic

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Authors: N. Ammouchi

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We have studied the effect of milling time on the structural and hyperfine properties of Ni45Al45Fe10 compound elaborated by mechanical alloying. The elaboration was performed by using the planetary ball mill at different milling times. The as milled powders were characterized by X-ray diffraction (XRD) and Mӧssbauer spectroscopy. From XRD diffraction spectra, we show that the β NiAl(Fe) was completely formed after 24 h of milling time. When the milling time increases, the lattice parameter increases, whereas the grain size decreases to a few nanometres and the mean level of microstrains increases. The analysis of Mӧssbauer spectra indicates that, in addition to a ferromagnetic phase, α-Fe, a paramagnetic disordered phase Ni Al (Fe) solid solution is observed after 2h and only this phase is present after 12h.

Keywords: NiAlFe, nanostructured powders, X-ray diffraction, Mӧssbauer spectroscopy

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Authors: Andrei Bejan, Luminita Marin, Dalila Belei

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Phenothiazine with electron-rich nitrogen and sulfur heteroatoms has a high electron-donating ability which promotes a good conjugation and therefore low band-gap with consequences upon charge carrier mobility improving and shifting of light emission in visible domain. Moreover, its non-planar butterfly conformation inhibits molecular aggregation and thus preserves quite well the fluorescence quantum yield in solid state compared to solution. Therefore phenothiazine and its derivatives are promising hole transport materials for use in organic electronic and optoelectronic devices as light emitting diodes, photovoltaic cells, integrated circuit sensors or driving circuits for large area display devices. The objective of this paper was to obtain a series of new phenothiazine derivatives by introduction of different electron withdrawing substituents as formyl, carboxyl and cyanoacryl units in order to create a push pull system which has potential to improve the electronic and optical properties. Bromine atom was used as electrono-donor moiety to extend furthermore the existing conjugation. The understudy compounds were structural characterized by FTIR and 1H-NMR spectroscopy and single crystal X-ray diffraction. Besides, the single crystal X-ray diffraction brought information regarding the supramolecular architecture of the compounds. Photophysical properties were monitored by UV-vis and photoluminescence spectroscopy, while the electrochemical behavior was established by cyclic voltammetry. The absorption maxima of the studied compounds vary in a large range (322-455 nm), reflecting the different electronic delocalization degree, depending by the substituent nature. In a similar manner, the emission spectra reveal different color of emitted light, a red shift being evident for the groups with higher electron withdrawing ability. The emitted light is pure and saturated for the compounds containing strong withdrawing formyl or cyanoacryl units and reach the highest quantum yield of 71% for the compound containing bromine and cyanoacrilic units. Electrochemical study show reversible oxidative and reduction processes for all the compounds and a close correlation of the HOMO-LUMO band gap with substituent nature. All these findings suggest the obtained compounds as promising materials for optoelectronic devices.

Keywords: electrochemical properties, phenothiazine derivatives, photoluminescence, quantum yield

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Authors: Bing–Jing Zhao, Chang-Kui Liu, Hong Wang, Min Hu

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Electron beam rapid manufacturing (EBRM) or Selective laser melting is an additive manufacturing process that uses 3D CAD data as a digital information source and energy in the form of a high-power laser beam or electron beam to create three-dimensional metal parts by fusing fine metallic powders together.Object:The present study was conducted to evaluate the mechanical properties ,the phase transformation,the corrosivity and the biocompatibility of Ti-6Al-4V by EBRM,SLM and forging technique.Method: Ti-6Al-4V alloy standard test pieces were manufactured by EBRM, SLM and forging technique according to AMS4999,GB/T228 and ISO 10993.The mechanical properties were analyzed by universal test machine. The phase transformation was analyzed by X-ray diffraction and scanning electron microscopy. The corrosivity was analyzed by electrochemical method. The biocompatibility was analyzed by co-culturing with mesenchymal stem cell and analyzed by scanning electron microscopy (SEM) and alkaline phosphatase assay (ALP) to evaluate cell adhesion and differentiation, respectively. Results: The mechanical properties, the phase transformation, the corrosivity and the biocompatibility of Ti-6Al-4V by EBRM、SLM were similar to forging and meet the mechanical property requirements of AMS4999 standard. a­phase microstructure for the EBM production contrast to the a’­phase microstructure of the SLM product. Mesenchymal stem cell adhesion and differentiation were well. Conclusion: The property of the Ti-6Al-4V alloy manufactured by EBRM and SLM technique can meet the medical standard from this study. But some further study should be proceeded in order to applying well in clinical practice.

Keywords: 3D printing, Electron Beam Rapid Manufacturing (EBRM), Selective Laser Melting (SLM), Computer Aided Design (CAD)

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Authors: M. Y. Lee, S. H. Park, S. M. Yu, H. S. Jo, C. G. Song

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Photoacoustic imaging is the imaging technology that combines the optical imaging with ultrasound. It also provides the high contrast and resolution due to optical and ultrasound imaging, respectively. For these reasons, many studies take experiment in order to apply this method for many diagnoses. We developed the real-time photoacoustic tomography (PAT) system using linear-ultrasound transducer. In this study, we conduct the experiment using swine and detect the blood of carotid artery and femoral artery. We measured the blood of femoral and carotid artery of swine and reconstructed the image using 950nm due to the HbO₂ absorption coefficient. The photoacoustic image is overlaid with ultrasound image in order to match the position. In blood of artery, major composition of blood is HbO₂. In this result, we can measure the blood of artery.

Keywords: photoacoustic tomography, swine artery, carotid artery, femoral artery

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Authors: I. Filikhin, B. Vlahovic

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We focus on a novel type of detection based on electron tunneling properties of double nanoscale structures in semiconductor materials. Semiconductor heterostructures as quantum wells (QWs), quantum dots (QDs), and quantum rings (QRs) may have energy level structure of several hundred of electron confinement states. The single electron spectra of the double quantum objects (DQW, DQD, and DQR) were studied in our previous works with relation to the electron localization and tunneling between the objects. The wave function of electron may be localized in one of the QDs or be delocalized when it is spread over the whole system. The localizing-delocalizing tunneling occurs when an electron transition between both states is possible. The tunneling properties of spectra differ strongly for “regular” and “chaotic” systems. We have shown that a small violation of the geometry drastically affects localization of electron. In particular, such violations lead to the elimination of the delocalized states of the system. The same symmetry violation effect happens if electrical or magnetic fields are applied. These phenomena could be used to propose a new type of detection based on the high sensitivity of charge transport between double nanostructures and small violations of the shapes. It may have significant technological implications.

Keywords: double quantum dots, single electron levels, tunneling, electron localizations

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Authors: Gabriel K. Nzulu, Lina Rostorm, Hans Högberg, Jun Liu, per Eklund, Lars Hultman, Martin Magnuson

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Altered and gangue quartz in hydrothermal veins from the Kubi Gold deposit in Dunkwa on Offin in the central region of Ghana are investigated for possible Au associated pathfinder minerals and to provide understanding and increase the knowledge of the mineral hosting and alteration processes in quartz. X-ray diffraction, air annealing furnace, differential scanning calorimetry, energy dispersive X-ray spectroscopy, and transmission electron microscopy have been applied on different quartz types outcropping from surface and bed rocks at the Kubi Gold Mining to reveal the material properties at different temperatures. From the diffraction results of the fresh and annealed quartz samples, we find that the samples contain pathfinder and the impurity minerals FeS₂, biotite, TiO₂, and magnetite. These minerals, under oxidation process between 574-1400 °C temperatures experienced hematite alterations and a transformation from α-quartz to β-quartz and further to cristobalite as observed from the calorimetry scans for hydrothermally exposed materials. The energy dispersive spectroscopy revealed elemental species of Fe, S, Mg, K, Al, Ti, Na, Si, O, and Ca contained in the samples and these are attributed to the impurity phase minerals observed in the diffraction. The findings also suggest that during the hydrothermal flow regime, impurity minerals and metals can be trapped by voids and faults. Under favorable temperature conditions the trapped minerals can be altered to change color at different depositional stages by oxidation and reduction processes leading to hematite alteration which is a useful pathfinder in mineral exploration.

Keywords: quartz, hydrothermal, minerals, hematite, x-ray diffraction, crystal-structure, defects

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Authors: Marzieh Joda, Narges Fallah, Neda Afsham

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Graphite-supported two different of morphology α and β -Ni (OH)₂ electrodes were prepared by electrochemical deposition at appropriate potentials with regard to Ni (II)/Ni (III) redox couple under alkaline and acidic conditions, respectively, for selective oxidation of ammonia to nitrogen in the direct electro-oxidation process. Cyclic voltammetry (CV) of the electrolyte containing NH₃ indicated mediation of electron transfer by Ni (OH)₂ and the electrode surface was analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectrometer (RS), and X-ray photoelectron spectroscopy (XPS). Results of surface characterization indicated the presence of α polymorphs which is the stable phase of Ni (OH)₂ /Graphite. Cyclic voltammograms gave information on the nature of electron transfer between nitrogen species and working electrode and revealed that the potential has depended on both nature ammonia oxidation and that of concentration. The mechanism of selective ammonia conversion to nitrogen and byproducts, namely NO₂- and NO₃- was established by Cyclic voltammograms and current efficiency. The removal efficiency and selective conversion of ammonia (0.1 M KNO₃ + 0.01 M Ni(NO₃)₂, pH 11, 250°C) on Nickel Oxide-hydroxide /Graphite was determined based on potential controlled experiments.

Keywords: Electro deposition, Nickel oxide-hydroxide, Nitrogen selectivity, Ammonia oxidation

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Authors: Naresh Radaliyagoda, Nigel M. Jennett, Rong Lan, David Parfitt

Abstract:

A series of length scale engineered multilayer material with temperature robust mechanical properties has been suggested. A range of polycrystalline copper sub-layers with the thickness varying from 1 to 25μm and buried in between two nickel layers was produced using electrodeposition dual bath technique. The structure of the multilayers was characterized using Electron Backscatter Diffraction and Scanning Electron Microscope. The interface effect on the hardness and elastic modulus was tested using Nano-indentation. Results of the grain size and layer thickness measurements, and indentation hardness have been compared. It is found that there is a combined length scale effect that improves mechanical properties in Ni/Cu multilayer structures.

Keywords: nano-indentation, size effect, multilayers, electrodeposition

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Authors: Goban Kumar Panneer Selvam

Abstract:

In past years, there is lots of death caused due to harmful gases. So its very important to monitor harmful gases for human safety, and semiconductor material play important role in producing effective gas sensors.A novel solvothermal synthesis method based on sol-gel processing was prepared to deposit tin oxide thin films on glass substrate at high temperature for gas sensing application. The structure and morphology of tin oxide were analyzed by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The SEM analysis of how spheres shape in tin oxide nanoparticles. The structure characterization of tin oxide studied by X-ray diffraction shows 8.95 nm (calculated by sheers equation). The UV visible spectroscopy indicated a maximum absorption band shown at 390 nm. Further dope tin oxide with selected metals to attain maximum sensitivity using dip coating technique with different immersion and sensing characterization are measured.

Keywords: tin oxide, gas sensor, chlorine free, sensitivity, crystalline size

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Authors: Mazouz Halima, Belghachi Abdrahmane

Abstract:

Effects of electron irradiation-induced deep level defects have been studied on both n/p and p/n indium phosphide solar cells with very thin emitters. The simulation results show that n/p structure offers a somewhat better short circuit current but the p/n structure offers improved circuit voltage, not only before electron irradiation, but also after 1MeV electron irradiation with 5.1015 fluence. The simulation also shows that n/p solar cell structure is more resistant than that of p/n structure.

Keywords: InP solar cell, p/n and n/p structure, electron irradiation, output parameters

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Authors: G. Çelik Gül, F. Kurtuluş

Abstract:

Rare earths containing complex metal oxides have drawn much attention due to physical, chemical and optical properties which make them feasible in so many areas such as non-linear optical materials and ion exchanger. We have researched a systematic study to obtain rare earth containing zirconium molybdate compound, characterization, investigation of crystal system and calculation of unit cell parameters.  After a successful synthesis of Nd₂Zr₃(MoO₄)₉ which is a member of rare earth metal containing complex oxides family, X-ray diffraction (XRD), High Score Plus/Rietveld refinement analysis, and Fourier Transform Infrared Spectroscopy (FTIR) were completed to determine the crystal structure. Morphological properties and elemental composition were determined by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. Thermal properties were observed via Thermogravimetric-differential thermal analysis (TG/DTA).

Keywords: Nd₂Zr₃(MoO₄)₉, powder x-ray diffraction, solid state synthesis, zirconium molybdates

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Authors: M. P. Joshi, F. Deganello, L. F. Liotta, V. La Parola, G. Pantaleo

Abstract:

For the first time, commercial iron nitrate was replaced by rust wastes, as a source of Iron for the preparation of LaFeO₃ powders by solution combustion synthesis (SCS). A detailed comparison with a reference powder obtained by SCS, starting from a commercial iron nitrate, was also performed. Several techniques such as X-ray diffraction combined with Rietveld refinement, mass plasma atomic emission spectroscopy, nitrogen adsorption measurements, temperature programmed reduction, X-ray photoelectron spectroscopy, Fourier transform analysis and scanning electron microscopy were used for the characterization of the rust wastes as well as of the perovskite powders. The performance of this ecofriendly material was evaluated by testing the activity and selectivity in the propylene oxidation, in order to use it for the benefit of the environment. Characterization and performance results clearly evidenced limitations and peculiarities of this new approach.

Keywords: perovskite type catalysts, solution combustion synthesis, X-ray diffraction, rust wastes

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Authors: Raana Babadi Fathipour

Abstract:

Hydrogels are three-dimensional structures formed by the interweaving of polymeric materials, possessing the remarkable ability to imbibe copious amounts of water. Numerous methodologies have been devised for examining and understanding the properties of these synthesized gels. Amongst them, spectroscopic techniques such as ultraviolet/visible (UV/Vis) and Fourier-transform infrared (FTIR) spectroscopy offer a glimpse into molecular and atomic aspects. Additionally, diffraction methods like X-ray diffraction (XRD) enable one to measure crystallinity within the gel's structure, while microscopy tools encompassing scanning electron microscopy (SEM) and transmission electron microscopy (TEM) provide insights into surface texture and morphology. Furthermore, rheology serves as an invaluable tool for unraveling the viscoelastic behavior inherent in hydrogels—a parameter crucial not only to numerous industries, including pharmaceuticals, cosmetics, food processing, agriculture and water treatment, but also pivotal to related fields of research. Likewise, the ultimate configuration of the product is contingent upon its characterization at a microscopic scale in order to comprehend the intricacies of the hydrogel network's structure and interaction dynamics in response to external forces. Within this present scrutiny, our attention has been devoted to unraveling the intricate rheological tendencies exhibited by materials founded on synthetic, natural, and semi-synthetic hydrogels. We also explore their practical utilization within various facets of everyday life from an industrial perspective.

Keywords: rheology, hydrogels characterization, viscoelastic behavior, application

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Authors: Yong-Cin Chen, Meng-Jiy Wang

Abstract:

This study reports to prepare cuprous oxide (Cu2O) particles with different dimension and shape for evaluating the antibacterial applications. In the preparation of Cu2O, the surfactant, cetyltrimethylammonium bromide (CTAB), was used as templates to modulate the size of the prepared Cu2O particles. Furthermore, ammonia water was used for adjusting the pH environment that four different shapes of particles including cubic, spherical, octahedral, and star-like Cu2O were synthesized. The physical characteristics of Cu2O particles were evaluated by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), UV/VIS spectrophotometer, and zeta potential meter/particle size analyzer (ZetaPALS). The resistance to bacteria was investigated against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) by applying the synthesized Cu2O particles that the qualitative analyses were facilitated by measuring the inhibition zone on Agar plate.

Keywords: copper oxide, cupric oxide, nanoparticles, antibacetrial

Procedia PDF Downloads 493