Scattering of elastic waves by an elastic sphere

The problem of scattering of plane compressional wave by an elastic sphere embedded in an isotropic elastic medium of different material properties is solved. Approximate formulas are derived for the displacement field, stress tensor, stess intensity factors, far-field amplitudes and the scattering cross section. It is assumed that the wave length is large compared to the radius of the scatterer. Various elastostatic limits are also presented.     

(Cu0.5Tl0.5)(Ba2–yCay)(CaMg)(Cu3–x Znx)O10–δ (y = 0, 1; x = 0, 2, 2.5, 2.8, 3) and (MxTl1–x)(BaCa)(CaMg) Zn3O10–δ (M = Ag,K; x = 0, 0.5) Superconductors for the Studies the role of Spin Density Waves in the Mechanism of High Tc Superconductivity

Journal of Superconductivity and Novel Magnetism - (Cu0.5Tl0.5)(Ba2–yCay)(CaMg)(Cu3–xZnx)O10–δ (y?=?0, 1; x?=?0, 2, 2.5, 2.8, 3) and...     

Polymer-coated CoFe<Subscript>2</Subscript>O<Subscript>4</Subscript> nanoassemblies as biocompatible magnetic nanocarriers for anticancer drug delivery

In this work, we report the preparation of cobalt ferrite nanoparticles (CFNPs) coated with hydrophilic polymers guar gum, gum arabic and poly (methacrylic acid) as magnetic nanocarriers and study their conjugation with doxorubicin for the drug release under applied magnetic field. The effect of polymer coating on structural properties is studied using Fourier transform infrared spectroscopy and powder X-ray diffractometry (XRD). The XRD analysis revealed that the polymer coating on the as-synthesized CFNPs has no influence on their crystallite size and it remains between 18 nm and 19 nm. The characteristic morphology, topography and the evidences of polymer coating over the CFNPs are investigated using scanning electron microscopy, atomic force microscopy and thermogravimetric analysis, respectively. Vibrating sample magnetometry revealed the ferromagnetic nature of uncoated CFNPs with a significant saturation magnetization ～77.2 emu g^?1. The dynamic light scattering measurements are also performed to determine the size of uncoated and coated CFNPs. UV–Visible spectroscopy demonstrated a profound loading (70–75%) of doxorubicin onto the magnetic nanocarriers and the efficient release of drug in the presence of external applied magnetic field. In vitro cytotoxic studies confirmed the cytocompatibility mode of coated CFNPs against Chinese Hamster Ovary and Huh-7 cell line, while 0.2 mg mL^?1 dose of drug-loaded magnetic nanocarriers inhibited the cell viability of Huh-7 up to 60%. These results strongly encourage the utilization of biocompatible magnetic nanocarriers in targeted drug delivery territory.     

Model for MHD viscoelastic nanofluid flow with prominence effects of radiation

Present phenomenon is dedicated to analyze the problem of steady state flow of an incompressible fluid model pertained to as magnetohydrodynamics viscoelastic nanofluid through a permeable plate. Continuity, momentum, energy, and concentration expressions are elaborated to comprehend nature of the fluid flow. Numerical solutions are presented. The arising mathematical problem is governed by interesting parameters which include viscoelastic parameter, magnetic field parameter, nanofluid parameter, radiation parameter, skin friction, Prandtle number, and Sherwood number. Solutions for the dimensionless velocity, temperature, and concentration fields and the corresponding skin friction, Nusselt number, and Sherwood number are determined and canvassed with the help of graphs for the distinct values of pertinent parameters.     

Scattering of elastic P and SV waves by a rigid elliptic cylindrical inclusion

The 2-dimensional problem of scattering of obliquely incident $\text{P}$ and SV waves by an infinite rigid elliptic cylinder embedded in an infinite, isotropic and homogeneous elastic medium is solved. Approximate formulas are derived for the displacement field, stress tensor, far-field amplitudes and the scattering cross section when the wave lengths are large compared to the distance between the two focii of the elliptic cylinder.     

Novel optical photorefractive storage-retrieval system using speckle coding technique in beam-fanning geometry

Abstract

An encoding technique based on speckle random patterns as carrier together with the beam-fanning concept is introduced to realize photo-refractive optical volume holographic memory. The set-up is based on beam-fanning geometry employing a single input beam in a BaTiO₃ crystal. Retrieval of information from this kind of memory system is very sensitive to code matching. Therefore, in the case of multiple storage, the cross-talk is minimized. The preliminary experimental results are presented with their possible applications in increasing the information storage capacity of volume holographic memories, with resultant reduced cross-talk. A dual-channel optical processor has also been realized wherein object information together with its contrast reversed version are obtained at the output channels simultaneously.     

Design criteria for transparent single-wall carbon nanotube thin-film transistors

A study based on two-dimensional percolation theory yielding quantitative parameters for optimum connectivity of transparent single-wall carbon nanotube (SWNT) thin films is reported. Optimum SWNT concentration in the filtrated solution was found to be 0.1 mg/L with a volume of 30 mL. Such parameters lead to SWNT fractions in the films of approximately Phi = 1.8 x 10(-3), much below the metallic percolation threshold, which is found to be approximately PhiC = 5.5 x 10(-3). Therefore, the performance of transparent carbon nanotube thin-film transistors is limited by the metallic SWNTs, even below their percolation threshold. We show how this effect is related to hopping or tunneling between neighboring metallic tubes.     

Cascade DNA Circuits Mediated CRISPR-Cas12a Fluorescent Aptasensor based on Multifunctional Fe3O4@hollow-TiO2@MoS2 Nanochains for Tetracycline Determination

Herein, for the first time, the CRISPR-Cas12a system is combined with aptamer, cascaded dynamic DNA network circuits, and Fe₃O₄@hollow-TiO₂@MoS₂ nanochains (Fe₃O₄@h-TiO₂@MoS₂ NCs) to construct an efficient sensing platform for tetracycline (TC) analysis. In this strategy, specific recognition of the target is transduced and amplified into H1-H2 duplexes containing the specific sequence of Cas12a-crRNA through an aptamer recognition module and the dual amplification dynamic DNA network. Subsequently, the obtained activated Cas12a protein non-specifically cleaves the adjacent reporter gene ssDNA-FAM to dissociate the FAM molecule from the quencher Fe₃O₄@h-TiO₂@MoS₂ NCs, resulting in the recovery of the fluorescence signal and further signal amplification. Particularly, the synthesized multifunctional Fe₃O₄@h-TiO₂@MoS₂ NCs composites also exhibit superb magnetic separability and photocatalytic degradation ability. Under optimal conditions, the aptasensor displays a distinct linear relationship with the logarithm of TC concentration, and the limit of detection is as low as 0.384 pg mL⁻¹. Furthermore, the results of spiked recovery confirm the viability of the proposed aptasensor for TC quantification in real samples. This study extends the application of the CRISPR-Cas12a system in the field of analytical sensing and contributes new insights into the exploration of reliable tools for monitoring and treating hazards in food and environment.     

Deformation-Induced Strengthening Mechanism in a Newly Designed L-40 Tool Steel Manufactured by Laser Powder Bed Fusion

The microstructural and mechanical properties of a newly designed tool steel (L-40), specifically designed to be employed in the laser powder bed fusion (LPBF) technique, were examined. Melt pool boundaries with submicron dendritic structures and about 14% retained austenite phase were evident after printing. The grain orientation after high cooling rate solidification is mostly < 110 >  _α∥ building direction (BD). Then, the heat treatment converted the microstructure into a conventional martensitic phase, reduced the retained austenite to about 1.5%, and increased < 111 >  _α∥BD texture. The heat-treated sample exhibits higher tensile strength (1720 ± 14 MPa) compared to the as-printed sample (1540 ± 26 MPa) along the building direction, mainly due to hardening caused by a lower volume fraction of retained austenite phase and precipitation of carbides. As a consequence of the strength-to-ductility trade-off, the heat-treated sample showed lower elongation (10% ± 2%) than that of the as-printed sample (18% ± 2%). It was observed that transformation-induced plasticity (TRIP) occurs in both the as-printed and heat-treated samples during tensile testing, which dynamically transforms the retained austenite into martensite, leading to improved ductility. The minimum driving force to initiate the displacive phase transformation is about 6000 J/mol, which was achieved during tensile testing. The strength and ductility of LPBF-produced L-40 were compared with the other LPBF-produced tool steels in literature; the data indicate that heat-treated L-40 has an excellent combination of strength and ductility complemented with high printability.