X-ray Difraction Research Articles

Features of Magnetocaloric Effect in Er(Co-Fe)2 Laves Phases

<p>In this work the results of measurements of heat capacity (C<sub>P</sub>) and magnetocaloric effect (MCE) in Er(Co<sub>1-</sub><sub>х</sub>Fe<sub>х</sub>)<sub>2</sub> system in the concentration range 0.07 ≤ x ≤ 0.80 are presented. Phase composition was controlled by X-ray difraction analysis. Heat capacity was measured in the temperature range 77-320 K. MCE has been studied within the temperature range 5-670 K in magnetic fields up to 70 kOe. It was found that Fe concentration increase caused the table-like (plateau) MCE temperature dependence for both magnetic entropy change date and direct ∆T-effect measurements independently on Fe concentration. The possible reasons of such behavior are discussed.</p>

Effect of gold nanoparticles in broadband near-infrared emission of Pr3+ doped B2O3–PbO–Bi2O3–GeO2 glass

B2O3–PbO–Bi2O3–GeO2 glass doped with Pr3+ was synthesized and implanted with Au+ using energy of 300keV and fluence of 1 × 1016cm−2. Annealing at moderate temperature, below the glass transition temperature, induced nucleation and growth of gold nanoparticles confirmed by the corresponding absorption band in the visible range and by transmission electron microscopy. The average size of the gold nanoparticles was about 2.8nm. The annealing also induced the crystallization of a nanometer thick layer at the implanted surface of the sample due to the defects created by ion implantation. Structural and optical properties of the samples were characterized by X-Ray difraction, Raman spectroscopy, thermal analysis and absorption and luminescence spectroscopy. Broadband infrared emission was observed under 488nm excitation covering a wide region of the optical telecommunication window (1.3μm–1.7μm). The intensity of this band was enhanced after thermal annealing, probably due to the local field effect of gold nanoparticles. From the optical absorption measurements, Judd–Ofelt theory was applied to evaluate the phenomenological intensity parameters Ωλ (λ=2, 4 and 6) and radiative properties like transitions probabilities, radiative lifetimes, branching ratio and stimulated emission cross-section. The large stimulated emission cross section and broadband effective bandwidth indicate that Pr3+ doped B2O3–PbO–Bi2O3–GeO2 glass containing gold nanoparticles is promising for use in optical amplification.

Recycled Alumina Production from the Anodizing Industry to Tubulation Coating of Petroleum Craking

The anodizing of aluminum is a common technique used to produce decorative and protective high quality film. This process results in significant volume of industrial sludge containing considerable amounts of colloidal aluminum hydroxide, which is a problem in the disposal of these industrial wastes due to the environmental impact. This paper aims at the treatment of theses residues, which were heat-treated at the temperatures of 200°C, 1000°C and 1400°C. After each treatment, the residues were put to the X-Ray Difraction and the X-ray Fluorescence analysis. In evaluating these results, it was found a gradual increase of the percentage of alumina at 1400°C to achieve 93%. With the acquisition of ceramic mass with a high content of alumina, the objective being to make a refractory to coat the petroleum refining pipes, thereby solving an environmental problem from the aluminum industry, presenting an alternative to the petroleum industry. These residues were compacted and immersed in land and sea petroleum for 30 days, after this period its mechanical properties were analyzed to study its response to the contact with the petroleum, where it was found that these remained kept.

Synthesis And Characterization of N-((6-methylpyridin-2-yl)carbamothioyl)thiophene-2-carboxamide and Its Co(II), Ni(II) and Cu(II) Complexes: Calculating of Molecular Orbitals, Antioxidant and Antitumor Activities

N-((6-methylpyridin-2-yl)carbamothioyl)thiophene-2-carboxamide, C 12 H 11 N 3 OS 2 (HL)and its Co(II), Ni(II) and Cu(II) complexes (ML 2 type) have been synthesized and characterized by elemental analysis, FT-IR , 1 H-NMR and HR-MS methods. In addition, HL was characterized by single crystal X-ray difraction method. The HL crystallizes in the monoclinic crystal system with P 1 2 1 / c 1 space group, Z =4, a=7.2326(8) A, b=18.3492(16) A, c=9.7724(9) A. The [ML 2 ] complex structures were optimized using B97D/TZVP level. Molecular orbitals of HL ligand was calculated at the same level. Antioxidant activity of the complexes were measured by using the DPPH and ABTS assays. Anticancer activity of the complex were studied MTT assay in MCF-7 breast cancer cells.

X-RD, SEM, FT-IR, DSC Studies of Polymer Blend Films of PMMA and PEO

Poly (methylmetacrylate)-Poly(ethylene oxide) (PMMA-PEO) polymers blend films were prepared using the solution casting method. The polymer thin films were characterized by X-ray difraction (XRD), Scanning Electron Microscopy (SEM), FTIR and differential scanning calorimetry (DSC) technique. The amorphous or crystalline nature of polymers has been confirmed by XRD analysis. The PMMA surface morphology shows rough surface and micro pore structure. Appearance of rough surface in SEM micrograph of pure PEO was suggested several crystalline domains. The surface morphology changes severely when PEO added to PMMA polymer, which shows the development of surface morphology from smooth to rough with increasing of PEO concentration in PMMA. FT-IR data shows that some of the bands found to be shifted and intensities of some of the bands are decreased and some are disappeared with the addition of PEO to PMMA when compared to pure PMMA and PEO, which suggests the coordination/ interaction between PMMA and PEO matrixes. DSC results showed that the melting temperatures (Tm) of PMMA and PEO blend decreases when compared to pure PEO, PMMA.

Fe-V-B ESASLI ALAŞIMLA YÜZEYİ SERTLEŞTİRİLMİŞ AISI 1020 ÇELİĞİNİN ÖZELLİKLERİ

In this study, Fe-V-B based hardfacing layer produced on AISI 1020 steel surface and analyzed by TIG welding technique. Ferrous vanadium, ferrous boron and armco iron prepared in Fe 10 V 5 B 5 , Fe 12 V 5 B 3 and Fe 14 V 5 B compositions were used for surface alloying treatment. Morphological properties, phase analysis and hardness measurement of hardfacing layers analyzed with optical microscope and scanning electron microscope, x-ray diffraction and vickes indentation, respectively. 2-3 mm thickness is observed from morphological investigation in Fe-V-B based hardfacing layer. Alloyed layers indicate good quality thick coating and porosity free of hardfacing. X-ray difraction analysis showed that the alloyed layers include FeV, Fe2B, VB ve Fe. It was shown that surface alloyed layer has composite structure including steel matrix and well distributed boride phases. The hardness of matrix of the alloyed layer and steels' un-coated layer are 205 HV 0,1 ve 150 HV 0,1 , respectively.

Study of photochromic silver-containing quartz-like glass using X-ray diffraction methods

Photochromic quartz-like glassess obtained by sintering plates of porous glass, which were successively impregnated with an aqueous solution of silver nitrates with or without the presence of sensitizers (copper or cerium nitrates) and halides (NH4Cl, KBr, KI) are studied using the methods of X-ray difraction and small-angle X-ray scattering (SAXS). It is shown that the main crystalline phases in the composition of lightsensitive regions formed in quartz-like glass are AgBr and KBr in the form of nanodimensional crystals with a size of 100–130 A. The sizes of the scattering regions according to the data of small-angle scattering are amount to 250–300 A. The temperatures of melting and crystallization of light-sensitive phases are determined from the temperature dependences of the SAXS intensity.

Carbonic anhydrase inhibitors: Synthesis, characterization and inhibition activities of furan sulfonylhydrazones against carbonic anhydrase I (hCA I)

The methane sulfonic acide hydrazide (1) was used to obtain furan sulfonylhydrazones; 2-acetylfuranmethanesulfonylhydrazone (2), 2-furaldehydemethanesulfonylhydrazone (3), 5-nitro-2-furaldehydemethanesulfonylhydrazone (4). The structures of furan sulfonylhydrazones were determined by using elemental analysis, FT-IR, 1H NMR, 13C NMR and UV–vis methods. The structure of 5-nitro-2-furaldehydemethanesulfonylhydrazone (4) was also supported with X-ray difraction method and found that compound 4 was crystallized in triclinic, space group P1¯. In order to gain insight into the structure of the compounds, we performed computational studies by using 6–311G(d,p) basic set in which B3LYP correlation function was implemented. The geometry of the sulfonylhydrazones were optimized at DFT method with Gaussian 09 program package and the global reactivity descriptors were also calculated by this basic set. The enzyme inhibition activities of the sulfonylhydrazones were investigated on carbonic anhydrase I (hCA I) isoenzyme and their activity parameters (Km, IC50 and Ki) were calculated by spectrophotometric method. And also, their inhibitor effects were also investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. Inhibition results show that compound 4 containing electron withdrawing group (NO2) has higher inhibition effect on hCA I isoenzyme than other's.

Synthesis of Mesoporous Silica Particles with Fibrous Morphology via Self-Assembly Process in Microemulsion System

In this research, several precursors were chosen to solve the drawbacks of using toxic and expensive chemicals in the synthesis of fibrous mesoporous silica particle via self-assembly process in microemulsion system. The synthesis of this emerging material normally is realized by using toxic cetylpyridinium bromide (CPB) as common structure directing agent in conjunction with combined cyclohexane and n-pentanol as expensive solvent and co-solvent, respectively. Less toxic cetyltrimethylammonium bromide (CTAB) can be the replacement for CPB but the use of this surfactant may drastically reduce the surface area of the resulting product. Herein, we report that the use of CTAB with combined toluene and n-butanol as affordable solvents can be used to synthesize fibrous mesoporous silica particle with high surface area. The material was well characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), N2 adsorption/ desorption, X-ray difraction (XRD)and thermal gravimetry (TG). This material might be applied in potential applications such as catalysis, drug delivery and adsorption. Moreover, it can be used as a hard-template for fabricating another novel fibrous materials.

A facile preparation method for synthesis of silica sulfuric acid/poly(o‐methoxyaniline) core–shell nanocomposite

A new nanocomposite of poly(o‐methoxyaniline) (POMA) is introduced by overlayer formation of POMA on silica. The key appealing feature of the synthesis is the role of silica sulfuric acid (SSA) both as solid acid dopant and template in overlayer self‐assembly of POMA on silica surface. Hereon siloxide group (Si―O−) of silica surface is replaced with dopant anion of SSA (≡Si―O―SO3−), which leads to formation of a overlayer of POMA on the silica surface. The composite particles are spherical in the nanoscale range of 50 nm without application of any external template (no‐template synthesis). Nanocomposite was fully characterized by various instrumentation methods: Fourier transform infrared (FT‐IR), ultraviolet–visible (UV–vis), thermogravimetric analysis (TGA), diffrential thermal analysis (DTA), elemental analysis (CHNS), energy dispersive X‐ray (EDX), X‐ray photoelectron spectroscopy (XPS) and X‐ray difraction (XRD). Based on XPS and CHNS results, it is demonstrated that the doping level of POMA is as high as 50% and for the first time the ratio of 4:2:2 is obtained for ―NH― (amine): ―HN.+― (polarons): HN+― (bipolarons), respectively. In fact, bipolarons may also coexist with polarons with a 1:1 ratio of them. Moreover, the synthesis benefits from the perspective of green chemistry which is preparation under solid‐state (solvent‐free) condition. Copyright © 2015 John Wiley & Sons, Ltd.

A new hybrid electrochromic material: vanadium oxide/ eriochrome black T

In this work, we describe the synthesis of a new hybrid material, which is consists of the eriochrome black T (sodium 1-[(1-hydroxynaphthcalen-2-yl-hydrazinylidene]-6-nitro-2- naphthol-4-sulfonate) and vanadium pentoxide xerogel using a melting sonoquenching technique. This hybrid material was apply in electrochromic electrodes. The hybrid material was characterized by X-ray difraction, FT-IR, AFM and spectroelectrochemically. The hybrid presented good reversibility and cyclability during 50 cycles studied, electrochromic efficiencies were about 50 cm2 C−1 (375 nm and 400 nm) and the ΔOD at 375 nm and 400 nm were 0.236 and 0.159 respectively wavelenghts. The response times were 0.7 to 3.3 s for 375 nm and 0.7 to 2.0 s for 400 nm. The hybrid is a potential material to be used in electrochromic applications.

Nanostructured D022-Mn3Ga with high coercivity

The microstructural and magnetic properties of Mn3Ga alloys with D022 phase have been investigated. Mn3Ga alloys with a nearly pure D022 phase were obtained via a heat treatment of ground arc-melted ingot powders with a cubic structure. X-ray difraction results show the formation of D022 after annealing the as-prepared ingot at 673 K for different annealing time intervals. It was found that the annealed samples are magnetically hard with a high HC of 11 kOe and a saturation magnetization of 20 emu g−1 at 300 K. Microstructure studies on the annealed powders showed the presence of small grains with size below 30 nm.

Silver Nanoparticles in TiO<sub>2</sub> Coatings for Potential Antimicrobial Coatings

This research aims to determine the effect of silver nanoparticles concentrations as antimicrobial coatings when doped to TiO2 coatings. The TiO2 coatings were prepared by sol–gel method initiating Titanium Isopropoxide–Propanol mixture as a precursor solution. The silver nanoparticles (40 nm) were then doped to the coating after sintering at 500°C. Two concentrations of silver nanoparticles, (50 ppm and 1000 ppm), were prepared for comparison in this study. Microstructure and crystalline phase of coatings were evaluated using Scanning Electron Microscope (SEM) and Glancing Angle X-Ray Difraction (GAXRD) technique. The antibacterial test was according to McFarland standard for detecting E.Coli, S.Aerues, fungas and Methicillin-Resistant Staphylococcus Aureus (MRSA). Results show that only coatings with the concentrations of 1000 ppm of silver nanoparticle function as antimicrobial coatings.

Application of Design of Experiments to the Alkaline Treatment in Mordenite Zeolite: Influence on Si/Al Ratio

This paper presents the application of Design of Experiments (DOE) to an alkaline treatment in mordenite zeolite, in order to identify the optimum settings of the variables (temperature and concentration of NaOH) that promote greater desilication. Samples of commercial mordenite with Si / Al ratio = 9 have been treated with aqueuos NaOH solution of various concentration (0,1;0,5;1,0) and temperature (30,50,70°C). Statistical analysis was carried out based on a 22 factorial design with center point replicates. Seven experiments were executed and the data of Si/Al ratio obtained. The resulting samples were characterized by x-ray difraction (XRD) and energy dispersive x-ray (EDX), to identify the structures and crystalline phases, and to determine the percentages of silicon and aluminum, respectively. In all samples, a decrease in the Si / Al ratio was observed, keeping the crystalline structure. The treatment was most effective, especially, at high temperature and NaOH concentration (experiment 4). DOE was shown to be a powerful techinique for the study of the variables, allowing determining which variables and value ranges have more influence on response, enabling optimization.

Dielectric properties of spark plasma sintered AlN/SiC composite ceramics

In this study, we have investigated how the dielectric loss tangent and permittivity of AlN ceramics are affected by factors such as powder mixing methods, milling time, sintering temperature, and the addition of a second conductive phase. All ceramic samples were prepared by spark plasma sintering (SPS) under a pressure of 30 MPa. AlN composite ceramics sintered with 30wt%–40wt% SiC at 1600°C for 5 min exhibited the best dielectric loss tangent, which is greater than 0.3. In addition to AlN and β-SiC, the samples also contained 2H-SiC and Fe5Si3, as detected by X-ray difraction (XRD). The relative densities of the sintered ceramics were higher than 93%. Experimental results indicate that nano-SiC has a strong capability of absorbing electromagnetic waves. The dielectric constant and dielectric loss of AlN-SiC ceramics with the same content of SiC decreased as the frequency of electromagnetic waves increased from 1 kHz to 1 MHz.

Thermal processes in the systems with Li-battery cathode materials and LiPF6 -based organic solutions

Thermodynamic instability of positive electrodes (cathodes) in Li-ion batteries in humid air and battery solutions results in capacity fading and batteries degradation, especially at elevated temperatures. In this work, we studied thermal interactions between cathode materials Li2MnO3, xLi2MnO3.(1 − x)Li(MnNiCo)O2,LiNi0.33Mn0.33Co0.33O2, LiNi0.4Mn0.4Co0.2O2, LiNi0.8Co0.15Al0.05O2 LiMn1.5Ni0.5O4, LiMn(or Fe)PO4, and battery solutions containing ethylene carbonate (EC) or propylene carbonate (PC), dimethyl carbonate (DMC) or ethylmethyl carbonate (EMC) and LiPF6 salt in the temperature range of 40–400 °C. It was found that these materials are stable chemically and well performing in LiPF6-based solutions up to 60 °C. The thermal decomposition of the electrolyte solutions starts >180 °C. The macro-structural transformations of cathode materials upon exothermic reactions were studied by transmission electron microscopy (TEM), X-ray difraction (XRD) and Raman spectroscopy. Differential scanning calorimetry (DSC) studies have shown that the exothermic reactions in the temperature range of 60–140 °C lead to partial decomposition of both the cathode material and electrolyte solution. The systems thus formed consisted of partially decomposed solutions and partially chemically delithiated cathode materials covered by reactions products. Thermal reactions terminate and this system reaches equilibrium at about 120 °C. It remains stable up to the beginning of the solution decomposition at about 180 °C. The increased content of surface Li2CO3 is found to significantly affect the thermal processes at high temperature range due to extensive exothermic decomposition at low temperatures.

PEMANFAATAN SERAT SELULOSA ECENG GONDOK (Eichhornia Crassipes) SEBAGAI BAHAN BAKU PEMBUATAN KERTAS: ISOLASI DAN KARAKTERISASI

Water hyacinth (Eichhornia crassipes) is an aquatic weeds and as water pollution which can be reduced by using its celloluse fiber as raw material for paper production. In this work, the cellulose fiber which produced from water hyacinth stems by chemical pulping method was isolated and characterized. The operating conditions for produced the highest yield of water hyacinth’s fiber by variation of NaOH concentration and cooking time were also investigated. Dry hyacinth stems on liquor/crop ratio was 7:1 (mL/g) and mixed with 1-5% (w/v) NaOH then degested in an autoclave (120 0C; 14,5 Psi) for 5, 10, 15, 30, 60 and 120 min. The operating condition which highest yield production was mixed with newspapers fiber with ratio 1:1, 2:1, 3:1 and 4:1. The NaClO 5.25% (v/v) was added into the mixture as bleaching agent, then pressed and dried as a paper. The highest water hyacinth fiber yield was obtained about 32.31% (2.5% w/v NaOH for 15 min). When mixed with newspaper fiber at loading ratio 2:1, the highest yield and density were obtained about 37.27% and 0.567 g/cm3, respectively. Base on observation by Scanning Electron Microscope (SEM), the diameter of water hyacinth’s fiber is 80-166 nm and waste newspaper fiber is ± 56 μm. In addition, in the presence of newspaper fiber in the product was increased the characteristic peaks of paper around 5.66% (cellulose I) and 8.26% (cellulose II) base on X-Ray Difraction (XRD) result. Keywords: Eichhornia crassipes, chemical pulping, autoclave, kertas

Synthesis, characterization, EDX, thermal, antioxidant, antibacterial, topographical, and gas adsorption studies of supramolecular tetraammoniumplatinate

Reaction of K2PtCl4 with N-alkyl-N-benzyl-N,N-dimethyl ammonium chloride (n = 8, 10, 12 and 14 for alkyl) yielded supramolecular bis(benzyldimethylalkylazaniumyl) tetrachloroplatinumdiuide (metallobenzalkonium8 (MBK8), MBK10, MBK12, MBK14) characterized with spectroscopic and energy dispersive X-ray techniques. X-ray difraction powder analysis was performed which confirmed the crystalline nature of the compound. UV/Vis study performed in dimethylformamide, dimethylsulphoxide (DMSO)/H2O, and DMSO/phosphate buffers under physiological conditions show stability of the supramolecular units, with [PtCl4]2−. Zeta potential with particle size distribution of MBK8 obtained with DLS-confirmed agglomeration of the coordinate units. Thermal analysis by differential scattering calorimetric showed an effect of alkyl chain on their heat retention. For MBK8, topographical analysis and specific surface area were investigated with atomic force microscopy and nitrogen adsorption method, illustrating an outstanding alignment in arrays of ionic units, and an extent of apparent cross-sectional areas, respectively. Antioxidant and antibacterial activities were determined with 1–2,5-diphenyl-2-picrylhydrazyl-scavenging effect and Gram-positive and Gram-negative bacteria, respectively. The compounds exhibited activities for both scavenging and bacteria.

Nonisothermal kinetics analysis of the dehydration of ziprasidone hydrochloride monohydrate by thermogravimetry

In the current work the kinetics of dehydration of ziprasidone hydrochloride monohydrate was studied by nonisothermal thermogravimetry. Ziprasidone hydrochloride monohydrate was heated from 30 to 150° with a heating rate of 5° per min under nitrogen gas atmosphere and weight loss data were collected. Powder X-ray difraction was used to characterize the solid before and after dehydration. The well accepted Coats-Redfern model fitting approach was applied to the thermogravimetry data for the kinetic analysis. Thirteen solid state reaction models were studied; among them one-dimensional diffusion model was found to be the best fit model for this reaction with an excellent correlation 0.9994. The Arrhenius parameters, activation energy, and pre-exponential factor were determined, the values were found to be 28 k.cal/mol and 9.53×1013 sec−1, respectively.

Effects of Different Heat Treatment Conditions on Fatigue Behavior of AA7075 Alloy

AbstractIn this study, the effect of different heat treatment processes applied to AA7075 alloys on the fatigue behavior was examined. The processes applied to AA7075 aluminum included annealing (O), high temperature pre-precipitating (HTPP), artificial aging (T6), retrogression and re-aging (RRA). The annealing heat treatment was performed for 2 hours at 500°C and samples were cooled in the furnace. In the artificial aging (T6) process, after the samples were solution treated for 2 hours at 500°C, they were quenched at room temperature and aged for 24 hours at 120°C. In the retrogression and re-aging process, samples were solution treated for 1 hour at 220°C after the T6 process and then re-aged for 24 hours at 120°C. In the high temperature pre-precipitating, pre-precipitates were formed for 30 minutes at 450°C and then, it was aged for 24 hours at 120°C. All samples were characterized through the scanning electron microscope (SEM + EDS), hardness measurements and X-ray difraction (XRD) techniques. At the end of experimental studies, SEM and EDS examinations XRD results revealed that η (MgZn2) phase formed in the microstructure following the HTTP, RRA and T6 heat treatment processes. As a result of the fatigue tests, the highest fatigue strength was measured in samples treated with artificial aging (T6), the lowest fatigue strength was measured in the annealed (O) samples.