The effect of pressure on transformation temperatures and some physical parameters of Fe–32Mn–6Si–3Cr shape memory alloy

An experimental investigation of the effect of pressure on shape memory behavior of Fe–32%Mn–6%Si–3%Cr alloy was undertaken. There are significant differences in the Gibbs free energy, dislocation density and transformation temperatures of the alloy due to applied pressure.     

Poly(crotonic acid-co-2-acrylamido-2-methyl-1-propanesulfonic acid)-metal complexes with copper(II), cobalt(II), and nickel(II): Synthesis, characterization and antimicrobial activity

Poly(crotonic acid-co-2-acrylamido-2-methyl-1-propanesulfonic acid) [P(CrA-co-AMPS)] (44.22:55.78) copolymer was prepared in N,N-dimethylformamide solution using the benzoyl peroxide (Bz₂O₂) as initiator. Cu(II), Ni(II) and Co(II) chelates of the copolymer were prepared and the formation constants of each complex were determined by the mole-ratio method using UV-vis spectroscopy. UV-vis studies showed that the complex formation tendency increased in the followed order: Cu(II) > Ni(II) > Co(II). The copolymer and its metal chelates were characterized by FTIR, TGA, X-ray diffraction and SEM analysis. Also, in vitro antimicrobial activity of the polymers were tested on various bacteria, and yeast.     

The temperature-dependent phase diagrams of the spin-3/2 Ising model on a FM/AFM two-layer lattice with a crystal field

The temperature-dependent phase diagrams of the spin-3/2 Ising model on a two-layer Bethe lattice with ferromagnetic (FM)/antiferromagnetic (AFM) intra-layer and either FM or AFM type inter-layer interactions are investigated under a constant magnetic field (H) and in the presence of a crystal field (D) by using exact recursion equations in a pairwise approach for coordination numbers q=3,4 and 6, in detail. In the light of the ground-state (GS) phase diagrams, the temperature-dependent phase diagrams of the model are obtained by studying the thermal variations of the order parameters, response functions and free energy. Then, they are illustrated on the (kT/J₁,J₃/J₁) and (kT/J₁,J₂/J₁) planes for the given system parameters. It is observed that the system exhibits first- and second-order phase transitions for all q values, and hence, in some cases, tricritical points. The existence of critical-end points and that of isolated points are also observed. The re-entrant behavior owes its presence to the two Néel temperatures, T_N, that are present for all q.     

A theory of high frequency vibrations of piezoelectric cyrstal bars

This paper presents a higher order, linear theory of piezoelectric crystal bars as in the same spirit as that of Mindlin. First, a power series representation in aerial coordinates is employed for both the mechanical displacement and electric potential fields. Next, with the help of a variational theorem deduced from Hamilton's principle, together with these series, the theory is established consistently. A hierarchy of 1-dimensional approximate equations of motion, charge equations of electrostatics, initial and boundary conditions, strain-displacement and electric field-electric potential relations, and macroscopic constitutive equations constitutes the theory, and it governs all the types of motions of piezoelectric crystal bars of uniform cross-section. Further, special cases of interest are pointed out. The solutions of the initial mixed boundary-value problems defined by this theory are proven to be unique.     

X-ray structure of {[μ-N,N′-Bis(salicylidene)-1, 3-propane-diamine] (dimethylformamide) zinc(II)} dibromo cadmium(ii)

The title compound, forms crystals which are the orthorhombic system, space group P2 ₁2₁2₁, with unit cell dimensions a = 10.3928(12) Å, b = 14.6298(13) Å, c = 15.9514(11) Å, V = 2425.3(4) ų. The cell contains four molecules. The structure is a heteronuclear dimeric complex with Zn^II and Cd^II ions. The coordination around the Zn^II ion is distorted square–pyramid and the Cd^II ion is distorted tetrahedral coordination. The Zn·sCd distance is 3.3594(7) Å.     

Medialization Laryngoplasty With Gore-Tex: An Animal Study

Vocal cord paralysis is a disease that can cause voice disability and aspiration problems. Expanded polytetrafluoroethylene (ePTFE; Gore-Tex) has been widely used in cardiovascular and plastic surgery; however, its biocompatibility and safety have not been established precisely in the larynx. In this study, the biocompatibility and safety of ePTFE used in vocal cord medialization in the rabbit larynx were assessed. Type 1 thyroplasty with Gore-Tex was performed on one side of the larynx in eight rabbits. A sham procedure was applied on the contralateral side of their larynx. The rabbits were sacrificed after 6 months, and macroscopic and microscopic evaluations and comparisons were performed. No significant inflammatory response to Gore-Tex or displacement of the implant was seen. There was only a tiny fibrotic capsule surrounding the material in each specimen. Intense eosinophilic cell infiltration was seen surrounding one rabbit specimen. Gore-Tex seems to be a biocompatible, stable, and reversible material that can be safely used in laryngeal framework surgery.     

Deconvolution of continuous internal bremsstrahlung spectra of 32P, 85Kr and 143Pr

An efficient method of deconvolution of the internal bremsstrahlung (IB) spectra accompanying the β‐decay in ³²P, ⁸⁵Kr and ¹⁴³Pr is presented. Experimental data is taken from the literature. The usual experimental values are folded with the response matrix of the detector system, and the Gold iteration technique is employed to deconvolve the detector response function for the continuous IB photon spectra. The response function of the detector is calculated using the peak to total ratio and the energy resolution of the detector. The results of the deconvolved IB spectra along with the theoretical calculations are presented. Copyright © 2007 John Wiley & Sons, Ltd.     

On positive solutions of a reciprocal difference equation with minimum

In this paper we consider positive solutions of the following difference equation $$x_{n + 1} = \min \left\{ {\frac{A}{{x_n }},\frac{B}{{x_{n - 2} }}} \right\}, A, B > 0.$$ We prove that every positive solution is eventually periodic. Also, we present here some results concerning positive solutions of the difference equation $$x_{n + 1} = \min \left\{ {\frac{A}{{x_n x_{n - 1} ...x_{n - k} }},\frac{B}{{x_{n - (k + 2)} ...x_{n - (2k + 2)} }}} \right\}, A, B > 0.$$      

Crystal structure of [2,6-bis(3,5-dimethyl-N-pyrazolyl)pyridine]-(azido)(chloro)copper(II).

In the title compound, the coordination around the Cu atom is a distorted square-pyramid involving three N atoms from the ligand and one N atom from the azido group at the basal plane. The Cl atom is located at the apical position. The Cu atom is 0.32(5)A above the basal plane. There are three intramolecular and four weak intermolecular hydrogen bonds in the structure. IR spectra confirm the asymmetric N3 stretching vibrations of the terminal azide group.