Magneto Optical Properties of FeB<Subscript>x</Subscript>Fe<Subscript>2−x</Subscript>O<Subscript>4</Subscript> Nanoparticles

In this study, FeB_xFe_2?xO₄ nanoparticles (NPs) were synthesized by the polyol method. The M–H hysteresis curves exhibit superparamagnetic characteristics that are both coercivity and remanent magnetization values are negligible. The particle size dependent Langevin function was applied to calculate the magnetic particle dimensions around 9 nm. The measured magnetic moments of NPs are in range of (1.52–2.2) µ_B and almost half or less with respect to 4 µ_B of bulk Fe ferrite. Magnetic anisotropy was specified as uniaxial and calculated effective anisotropy constants (K _eff ) are between 43.3 × 10⁴ and 19.4 × 10⁴ emu/g. The UV–Vis diffuse reflectance spectroscopy and Kubelka–Munk theory were used to determine the optical properties. The estimated optical band gap values (2.15–2.48 eV) of FeB_xFe_2?xO₄ NPs are bigger with respect to reported values (1.88–2.12 eV) for Fe₃O₄ NPs in the literature. The bigger E _g values are mainly attributed to B concentration and partly to quantum confinement effect.     

Multi-response optimization of thermophysiological comfort properties of polyester filament woven fabrics

Microfilament woven fabrics are used in many products such as sportswear, rainclothes, windproof clothes, sleeping bags and surgical gowns and for these products, thermophysiological comfort properties are of prime importance. In this study, it is intended to investigate the effects of filament linear density and weft sett on thermophysiological comfort properties. Also, an optimization model was developed to determine the optimum filament linear density and weft sett for the best response variables of air permeability, water vapour permeability and thermal resistance. Four different weft sett and five different filament linear densities were applied in weft direction with three different weave types. In doing so, 60 woven fabric samples were produced. According to ANOVA results and experimental observations, it is observed that, the effect of filament linear density on air and water vapour permeability was minor on microfilament range, whereas the differences between conventional filament and microfilament sample groups are considerable. Also, higher weft sett causes decreasing of air and water vapour permeability. On the other hand, there is no obvious consistent trend for thermal resistance of samples with different filament linear density and weft sett.     

Triethanolamine Assisted Hydrothermal Synthesis of Superparamagnetic Co3O4 Nanoparticles and Their Characterizations

We present, for the first time, on a facile route for the fabrication of highly crystalline Co₃O₄ nanoparticles using trietanolamine (TEA) assisted hydrothermal synthesis route and single precursor. Synthesized material has been evaluated for its structural, morphological and magnetic properties using x-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM) techniques. The material has been identified as highly crystalline Co₃O₄, with superparamagnetic character due to size confinement. Estimated particle size from SEM is about 10 nm, which is close to the magnetic domain size (estimated from VSM as 8.4 ± 1.7 nm) and the crystallite size (estimated from XRD as 11 pm 4 nm), which reveal nearly single crystalline character of Co₃O₄ nanoparticles. The suggested route is facile, which provides a good size control over the nanoparticles, and can be used for the fabrication of other ceramic materials.     

Solvothermal Synthesis of SrFe12O19 Hexaferrites: Without Calcinations

In this study, the effect of temperature on the hydrothermal synthesis of single-phase SrFe₁₂O₁₉ hexaferrite (SrM) was investigated. For this synthesis, annealing or calcination process was applied. The Fe/Ba molar ratio was taken as 8:1. In this study, single-phase SrM NPs were synthesized via hydrothermal method. XRD patterns showed the presence of the hard (SrM) phase in the samples treated at 200 and 220 ^°C. Besides, formation of hexagonal plate-like samples was observed in SEM micrographs. Despite the low magnetization and coercive field values, the presence of the SrM phase was also shown in magnetization measurements. A reduced magnetization was explained by the existence of SrCO₃ and Fe₂O₃ phases, and a high shape anisotropy is probably the reason of low coercivity.     

CoFe2O4–Pd (0) Nanocomposite: Magnetically Recyclable Catalyst

This study reports on the fabrication and characterization of magnetically recyclable catalysts of CoFe₂O₄–Pd (0) nanocomposite as highly effective catalysts for reduction reactions (hydrogenation reactions) in liquid phase. The CoFe₂O₄ nanoparticles were prepared by a sonochemical method, and the reduction of Pd²⁺ was accomplished with polyethylene glycol 400 (PEG-400). The formation of CoFe₂O₄–Pd (0) magnetically recyclable catalysts (MRCs) was confirmed by X-ray diffraction, Fourier transform infrared spectroscopy, and inductively coupled plasma. Vibrating sample magnetometer showed the ferromagnetic property of the product. The crystallite size (16 ± 4 nm) obtained from XRD was consistent with the particle size (15 ± 5 nm) from TEM. Thus, formed CoFe₂O₄–Pd (0) MRCs showed a very high activity in reduction reactions of 4-nitroaniline and 1,3-dinitrobenzene in liquid phase. Magnetic character of this system allowed recovery and multiple uses without significant loss of its catalytic activity. Graphical Abstract

?Preparation steps for fabricating CoFe₂O₄–Pd (0) MRCs     

Diphallus with urethral duplication: a rare case

We report on a case of glandular diphallus with incomplete urethral duplication associated with rotation anomaly in the right kidney, and a bifid pelvis and an ectopic ureteral orifice in the left kidney. The bladder was single with good sphincter control. At operation, the hipoplasic glans was resected and the urethra which opened into this glans anastomosed alongside the other urethra. Diphallus and incomplete urethral duplication are discussed.     

Sliding window adaptive fast QR and QR-lattice algorithms

Sliding window formulations of the fast QR and fast QR-lattice algorithms are presented. The derivations are based on the partial triangularization of raw data matrices. Three methods for window downdating are discussed: the method of plane hyperbolic rotations, the Chambers' method, and the LINPACK algorithm. A numerically ill-conditioned stationary signal and a speech signal are used in finite wordlength simulations of the full QR (nonfast), fast QR, and QR-lattice algorithms. All algorithms are observed to be numerically stable over billions of iterations for double-precision mantissas (53 bits), but as the number of bits is decreased in the mantissa, the algorithms exhibit divergent behavior. Hence, practically, the algorithms can de regarded as numerically stable for long wordlengths     

Complex degree of coherence for partially coherent general beams in atmospheric turbulence

With the use of the general beam formulation, the modulus of the complex degree of coherence for partially coherent cosh-Gaussian, cos-Gaussian, Gaussian, annular and higher-order Gaussian optical beams is evaluated in atmospheric turbulence. For different propagation lengths in horizontal atmospheric links, the moduli of the complex degree of coherence at the source and receiver planes are examined when reference points are taken on the receiver axis and off-axis. In the on-axis case, it is observed that in propagation, the moduli of the complex degree of coherence are symmetrical and look like the intensity profile of the related coherent beam propagating in a turbulent atmosphere. For all the beams considered, the moduli of the complex degree of coherence profiles turn into Gaussian shapes beyond certain propagation lengths. In the off-axis case, the moduli of complex degree of coherence patterns become drifted at the earlier propagation lengths. Among the beams investigated, the cos-Gaussian beam is found to be almost independent of the changes in the source partial coherence parameter, and the annular beam seems to be affected the most against the variations of the source partial coherence parameter.     

Acid Functionalized Multiwall Carbon Nanotube/Magnetite (MWCNT)-COOH/Fe3O4 Hybrid: Synthesis, Characterization and Conductivity Evaluation

A functionalized multiwall carbon nanotube (MWCNT)–COOH/Fe₃O₄ hybrid was fabricated by co-precipitation method. Fe₃O₄ nanoparticles were stably attached to the surface of carboxyl groups (COOH). The presence of Fe₃O₄ nanoparticles and their surface conjugation to MWCNT have been confirmed by XRD, TEM and FT-IR techniques. Magnetic evaluation revealed a superparamagnetic character of the hybrid and therefore the attached Fe₃O₄ nanoparticles. The crystallite size (9 ± 3 nm), particle size (9 ± 2 nm) and magnetic domain size estimated for Fe₃O₄ are consistent with each other, which reveal the single crystalline character of the nanoparticles. Electrical conductivity and dielectric behavior have also been characterized by utilizing impedance spectroscopy up to 3 MHz for an isotherm line varying from 293 to 393 K by 10 K steps. Electrical characteristics and its complex dielectric approaches might be elucidated with the existence of a conventional tunneling conduction mechanism of temperature-independency. The AC conductivity of MWCNT–COOH/Fe₃O₄ hybrid could also be a consequence of the estimations of the universal dynamic response.