Investigation on Physicomechanical,Thermal, and Morphological of Dipodal Silane-Modified Walnut Shell Powder-Filled Polyurethane Green Composites and Their Application for Removal of Heavy Metal Ions from Water

Dipodal silane-modified walnut shell powder polyurethane green composites have been prepared with different weight fractions of walnut shell powder viz., 0, 3, 6, and 10?wt% with surface-modified dipodal silane. The properties of dipodal silane-modified walnut shell powder-filled polyurethane green composites was investigated by tensile testing, Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The polyurethane/dipodal silane-modified walnut shell powder has been fabricated based on 3-aminopropyltriethoxysilane and γ-glycidoxypropyl trimethoxysilane. The green composites were analyzed by ultraviolet–visible in two different water solutions with Ni²⁺ and Pd²⁺ ions concentrations.     

The anisotropic R-criterion for crack initiation

The anisotropic nature of mixed modes I-II crack tip plastic core region and crack initiation is investigated in this study using an angled crack plate problem under various loading conditions. Hill’s anisotropic yield criterion along with singular elastic stress field at the crack tip is employed to obtain the non-dimensional variable-radius crack tip plastic core region. In addition, the R-criterion for crack initiation proposed by the authors for isotropic materials is also extended to include anisotropy. The effect of Hill’s anisotropic constants on the shape and size of the crack tip plastic core region and crack initiation angle is presented for both plane stress and plane strain conditions at the crack tip. The study shows a significant effect of anisotropy on the crack tip core region and crack initiation angle and calls for further development of anisotropic crack initiation theory.     

Determination of ultra trace levels of copper in food samples by a highly sensitive adsorptive stripping voltammetric method

A new method is presented, for the determination of copper, based on adsorptive stripping voltammetry of the complex of copper with thiosemicarbazide at a hanging mercury drop electrode (HMDE). The most suitable operating conditions and parameters, such as pH, accumulation potential, deposition time, ligand concentration and scan rate, were selected. The calibration graph for copper (II) was linear over the concentration range 0.01–90.0 ng/ml; the detection limit of the method was 0.007 ng/ml. The interferences of some common ions were studied and the method was found suitable for the determination of copper (II) in rice, tea, tomato, blood and water samples. Moreover, with the use of the proposed method, there is a considerable improvement in the detection limit, the linear dynamic range and the deposition time, compared with the methods other than adsorptive stripping voltammetry for the determination of copper.     

The Influence of Crysnanoclay Addition on Mechanical and Thermal Properties of Thermoplastic Polyurethane Elastomeric with Polycarbonate Nanocomposites

A series of crysnanoclay-loaded thermoplastic polyurethane (TPU) elastomer/polycarbonate (PC) nanocomposites have been prepared using twin screw extruders. The physicomechanical properties such as tensile behaviors, flexural properties and impact strength of the composites have been reported. Significant improvement in tensile modulus and flexural modulus were noticed for nanocomposites. The thermal characteristics of nanocomposites have been determined by thermogravimetric analysis (TGA) techniques. Thermal degradation kinetic parameters such as energy of activation (E_a) have been calculated from TGA thermograms for the nanocomposites using three mathematical models namely; Coats–Redfern, Horowitz – Metzger and Broido's methods and the results are compared. The effect of crysnanoclay on the storage modulus (E′), loss modulus (E″), and damping factor (tan δ) as a function of temperature have been measured by dynamic mechanical analysis (DMA). The storage moduli of nanocomposites have been increased after incorporating crysnanoclay in polymer matrix.     

HSA loaded with CoFe2 O4 /MNPs as a high‐efficiency carrier for epirubicin anticancer drug delivery

Drug delivery is one of the most important challenges in the domain of health. Non‐toxic and biocompatible carriers are provided by human serum albumin nano‐capsule (HSA/NC) for drug delivery applications. In this study, HSA, with high loadings of drug‐modified cobalt ferrite (CoFe₂ O₄) magnetic nanoparticle (CoFe₂ O₄ /MNPs) was fabricated for epirubicin anticancer drug delivery. In the initial step, CoFe₂ O₄ /MNPs was synthesised via co‐precipitation technique and characterised by X‐ray powder diffraction, vibrating sample magnetometry, energy dispersive X‐ray analysis, scanning electron microscopy and map analysis. Furthermore, CoFe₂ O₄ /MNPs and epirubicin were loaded into HSA/NC and utilised as a novel system against breast cancer cell line (MCF‐7). IC₅₀ for free epirubicin, unloaded CoFe₂ O₄ /MNPs/HSA/NC, CoFe₂ O₄ /MNPs and epirubicin‐loaded CoFe₂ O₄ /MNPs/HSA/NC were 7.7, 2400, 840 and 430 μg/ml, respectively. The results obtained revealed high cytotoxicity effect of epirubicin‐loaded CoFe₂ O₄ /MNPs on breast cancer cell line.Inspec keywords: drug delivery systems, biomedical materials, nanoparticles, cobalt compounds, ferrites, nanomedicine, proteins, molecular biophysics, drugs, magnetic particles, nanomagnetics, nanofabrication, precipitation (physical chemistry), X‐ray diffraction, X‐ray chemical analysis, scanning electron microscopy, cancer, cellular biophysics, toxicology, magnetic hysteresisOther keywords: HSA, high‐efficiency carrier, epirubicin anticancer drug delivery, human serum albumin nanocapsule, drug‐modified cobalt ferrite magnetic nanoparticle, coprecipitation technique, X‐ray powder diffraction, vibrating sample magnetometry, energy dispersive X‐ray analysis, scanning electron microscopy, map analysis, breast cancer cell line, cytotoxicity effect, CoFe₂ O₄      

Secrecy performance analysis of single-input multiple-output generalized-<Emphasis Type="Italic">K</Emphasis> fading channels

In this paper, the transmission of confidential messages through single-input multiple-output (SIMO) independent and identically generalized-K (K_G) fading channels is considered, where the eavesdropper overhears the transmission from the transmitter to the receiver. Both the receiver and the eavesdropper are equipped with multiple antennas, and both active and passive eavesdroppings are considered where the channel state information of the eavesdropper’s channel is or is not available at the transmitter. The secrecy performance of SIMO K_G systems is investigated. Analytical expressions for secrecy outage probability and average secrecy capacity of SIMO systems are derived via two different methods, in which K_G distribution is approximated by the Gamma and mixture Gamma distributions, respectively. Numerical results are presented and verified via the Monte-Carlo simulation.     

Effect of Build Height on Temperature Evolution and Thermally Induced Residual Stresses in Plasma Arc Additively Manufactured Stainless Steel

Metallurgical and Materials Transactions A - Plasma arc additive manufacturing (PAM) is receiving an increasing attention because of its efficiency of dimensional size and cost, as compared to...     

Laser consecutive pulse heating and phase change: Influence of spatial distribution of laser pulse intensity on melting

Laser consecutive pulse heating of solid surface and the influence of the laser pulse parameter on the melting and mushy zone formation in the irradiated region are investigated. The laser pulse parameter (β) defines the spatial distribution of the laser pulse power at the irradiated surface; in which case, β = 0 represents the Gaussian profile while β = 1 corresponds to the ring type of laser power distribution with the peak intensity away from the center (symmetry axis). β is set in such a way that the energy content in each pulse with different β values becomes the same. The control volume approach is used when modeling the heating and phase change processes. The laser pulse parameter is selected to alter the laser power intensity distribution across the irradiated surface while modifying the location and magnitude of the laser peak power intensity at the irradiated surface. It is found that the laser pulse parameter alters the sizes of the melting and mushy zones in the surface region.     

Automated Visual Surveillance in Realistic Scenarios

In this article, we present Knight, an automated surveillance system deployed in a variety of real-world scenarios ranging from railway security to law enforcement. We also discuss the challenges of developing surveillance systems, present some solutions implemented in Knight that overcome these challenges, and evaluate Knight's performance in unconstrained environments     

Preparation and Characterization of Carvacrol Loaded Polyhydroxybutyrate Nanoparticles by Nanoprecipitation and Dialysis Methods

In this investigation, preparation of carvacrol loaded polyhydroxybutyrate (PHB) nanoparticles was performed by nanoprecipitation and dialysis methods. PHB particles were obtained by nanoprecipitation method without and with low concentration of Tween 80 or pluronic as surfactant. Nano‐ and micro‐sized particles were formed with trimodal distribution and large aggregates. Size and distribution of nanoparticles were decreased when concentration of Tween 80 was increased to 1% (v/v) in water as polar phase. PHB nanoparticles had narrow size (157 nm) with monomodal distribution. Nanoparticles, which were prepared by dialysis method had 140 nm in diameter with monomodal distribution. Carvacrol was used as a lipophilic drug and entrapped in optimized nanoparticles formulation by nanoprecipitation and dialysis methods. Entrapment efficacy was 21% and 11%, respectively. Morphology of PHB nanoparticles was spherical. The results of kinetic release study showed that carvacrol was released for at least 3 days. Release kinetic parameters showed a simple Fickian diffusion behavior for both formulations. Carvacrol loaded PHB nanoparticles had good dispersion into the agar medium and antimicrobial activity against Escherichia coli. This study describes the 1st work on loading of carvacrol into the PHB nanoparticles by nanoprecipitation and dialysis methods.