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This study investigates the stability response of pin ended complex angle sections subjected to axial compression. Eight different lipped angle sections (including plain and various stiffened) are considered. The thickness of the sections is adjusted such that the cross-sectional area of all sections is same. Based on the 'signature curve' obtained from preliminary finite strip analysis using CUFSM, height of the columns is considered to be 1m to ensure that flexural-torsional buckling mode governs their failure. Thereafter, linear and nonlinear finite element buckling analyses are carried out with the help of ABAQUS to determine the primary elastic buckling mode and column strengths, respectively. Nominal column strengths are quantified as per AISI S100-16 and are compared with the corresponding numerical column strengths obtained from finite element analysis. A good agreement between the numerical and nominal column strengths is noted. The findings of this numerical study indicate the superior performance of stiffened CFS angle sections over the plain angle section. [ABSTRACT FROM AUTHOR]

The codoped Bi1-xLaxFe1-yNiyO3 (x = 0.0, 0.1; y = 0.0, 0.05) samples are processed by solid-state reaction route in order to study structural, dielectric and ferroelectric properties. X-ray diffraction patterns of La/Ni doped samples have been performed using the rhombohedral (R3c) symmetry. Raman scattering measurement infers nine Raman active phonon modes. The substitution of Ni ion at Fe-site in BiFeO3 essentially changes the modes position i.e. all the modes are observed to shift at lower wave number. Frequency variation of the dielectric constant (ε') and dielectric loss (tanδ) has been investigated. It decreases with increasing frequency of the applied alternating field and become constant at high frequencies signifies substantial role of interfacial polarization. The remnant polarization and coercive field for BLFO, BFNO, BLFNO are 0.08, 0.03, 0.64 μC/cm2 and 0.24, 0.22, 0.25 kV/cm, respectively. La/Ni ion doping in BFO has successfully enhanced the polarization. [ABSTRACT FROM AUTHOR]

We present the results on atomic and lattice structure of the polycrystalline spinel ferrites system Co1-x TixFe2O4 (x = 0.0, 0.25, 0.50) synthesized by following the conventional solid-state reaction route. The observed X-ray diffraction (XRD) data confirms that all the prepared samples are indexed in cubic crystal structure (space group Fd3m). Diffraction pattern showed TiO2 phase due to presence of Ti+4 ions. Four Raman active phonon modes are observed for CoFe2O4 sample existing around 295, 462, 585, 689, cm-1 as Eg, T2g(2), T2g(3), and A1g, respectively. With 25 % Ti ion doping, the peak T2g(3) disappears, while to that T2g(1) emerges. This is an indication of presence of TiO2 phase in Co0.75Ti0.25Fe2O4 and Co0.5Ti0.5Fe2O4 ceramics. [ABSTRACT FROM AUTHOR]

The codoped Bi1-xLaxFe1-yNiyO3 (x = 0.0, 0.1; y = 0.0, 0.05) samples are processed by solid-state reaction route in order to study structural, dielectric and ferroelectric properties. X-ray diffraction patterns of La/Ni doped samples have been performed using the rhombohedral (R3c) symmetry. Raman scattering measurement infers nine Raman active phonon modes. The substitution of Ni ion at Fe-site in BiFeO3 essentially changes the modes position i.e. all the modes are observed to shift at lower wave number. Frequency variation of the dielectric constant (ε') and dielectric loss (tanδ) has been investigated. It decreases with increasing frequency of the applied alternating field and become constant at high frequencies signifies substantial role of interfacial polarization. The remnant polarization and coercive field for BLFO, BFNO, BLFNO are 0.08, 0.03, 0.64 μC/cm2 and 0.24, 0.22, 0.25 kV/cm, respectively. La/Ni ion doping in BFO has successfully enhanced the polarization. [ABSTRACT FROM AUTHOR]

In this work, Sn doped NiO nanoparticles were synthesized by co-precipitation route to explore the impact of doping on lattice structure, dielectric constant and magnetization. X-ray diffraction analysis confirmed cubic (Fd-3m) structure of Sn doped NiO. Average crystallite size decreases from 78.2 nm (Ni0.95Sn0.05O) to 64.23 nm (Ni0.8Sn0.2O). Scanning electron microscopy images confirm that nanocrystals have agglomerated spherical morphology. The Raman spectrum exhibits a strong, broad peak at 410 cm-1 and is attributed to the Ni-O stretching mode and doped samples show a blue shift. The dielectric constants at about 1 Hz are measured to be about 1.795, 1.030, 0.442, and 0.302 × 103 for Ni1-xSnxO (x = 0.05, 0.1, 0.15, 0.2), respectively. The dielectric constant in nanoparticles of doped Ni1-xSnxO is three orders of magnitude higher as compared to pure NiO ceramics. The nature of magnetization - applied field (M-H) infers paramagnetic behaviour for Sn doped NiO nanoparticles. [ABSTRACT FROM AUTHOR]

Samples of transition metal (TM) doped Zn0.94Mn0.01TM0.05O (TM = Co, Ni, Cu) nanocrystalline were successfully prepared by sol gel auto combustion method. X-ray diffraction pattern infers that Zn0.94Mn0.01TM0.05O (TM = Co, Ni, Cu) samples are in single phase with hexagonal wurtzite structure (P63mc space group). Raman spectroscopy of all the studied samples reveals four vibrational phonon modes corresponding to ZnO centered at 331, 380, 410, and 438 cm-1, that are assigned to the E2 (H)-E2(L), A1(TO), E1(TO), and E1(LO) modes, respectively. The UV transmission spectroscopes of all the samples are investigated to calculate band gap. It was found that the band gap of Zn0.94Mn0.06O was increased from 3.19 to 3.25eV by doping 5% transition metal oxide. [ABSTRACT FROM AUTHOR]

The composites of (1-x) La0.67Ba0.33MnO3 (LBMO) + xBaTiO3 (BTO) (x = 0, 0.25 and 1.0) were synthesized by conventional solid-state reaction method. Rietveld refinement was employed to characterize the structural information of the prepared ceramics. The result of the Rietveld refinement of X-ray powder diffraction of La0.67Ba0.33MnO3 and BaTiO3 shows that these compounds crystallize in rhombohedral (R3c) and tetragonal (P4mm), respectively. The structural parameters and the reliability factors for the LBMO-BTO composite ceramics were successfully determined by the Rietveld refinement. At room temperature, Raman active phonon modes predicted by the group theory were observed only in BaTiO3 and composite sample. Pure LBMO does not show any Raman active Phonon mode at room temperature. [ABSTRACT FROM AUTHOR]

A series of Cr doped Mn-Zn ferrites with compositional formula Mn0.5Zn0.5-xCrxFe2O4 (x = 0, 0.3, 0.5) were prepared by solid-state reaction route. X-ray diffraction (XRD) analysis reveals that the samples prepared are polycrystalline cubic spinel in structure (Fd3m) with some secondary phase of α-Fe2O3. Slight variation in the lattice parameter of Cr doped Mn0.5Zn0.5Fe2O4 has been observed due to difference in ionic radii of cations. Small shift in Raman modes towards higher wave number has been observed. Further the line width decreases with the doping ions. A giant dielectric constant ~104 is observed for parent Mn0.5Zn0.5Fe2O4 which is found to decrease with increase in Cr2+ doping. Low dielectric loss is observed for Mn0.5Zn0.5Fe2O4 and improves with Cr2+ doping at Zn2+ site. [ABSTRACT FROM AUTHOR]

Transition metal Cu2+ doped Mg-Zn ferrite [Mg0.5Zn0.5-xCuxFe2O4 (0.0 ≤ x ≤ 0.5)] were prepared by sol gel auto combustion (SGAC) method to probe the structural, vibrational and electrical properties. X-ray diffraction (XRD) pattern reveals a single-phase cubic spinel structure without the presence of any secondary phase corresponding to other structure. The average particle size of the parent Mg0.5Zn0.5Fe2O4 is found to be ~29.8nm and is found to increase with Cu2+ doping. Progressive reduction in lattice parameter of Mg0.5Zn0.5Fe2O4 has been observed due to difference in ionic radii of cations with improved Cu doping. Spinel cubic structure is further confirmed by Raman spectroscopy. Small shift in Raman modes towards higher wave number has been observed in doped Mg-Zn ferrites. The permittivity and dielectric loss decreases at lower doping and increases at higher order doping of Cu2+. [ABSTRACT FROM AUTHOR]

A series of Ni-Zn ferrite with compositional formula Ni1-xZnxFe2O4 (0.0 ≤ x ≤ 0.5) were prepared by solid-state reaction route. The influence of the Zn content on the structural and dielectric properties of NiFe2O4 was investigated using X-ray powder diffraction (XRD), Raman spectroscopy and dielectric measurements. XRD analysis reveals that the samples are polycrystalline single-phase cubic spinel in structure excluding the presence of any secondary phase corresponding to any structure. Slight variation in the lattice parameter of Zn doped NiFe2O4 has been observed due to difference in ionic radii of cations. Raman analysis reveals the doublet like nature of A1g mode for all synthesized samples. Small shift in Raman modes and increment in the line width has been observed with the doping ions. Furthermore, room temperature dielectric properties of all the prepared samples have been reported. It is observed that for each sample the dielectric constant decreases with an increase of frequency and becomes constant at higher frequencies. [ABSTRACT FROM AUTHOR]