Modelling of probability of failure of concrete columns

This paper predicts the probability of failure or short and long columns of square reinforced concrete for deterministic and probabilistic loads. The effect of various parameters; width, length of column, effective length coefficient, percentage of steel, axial load, grade of concrete and random numbers; on the probability of failure of the column is studied. The material, geometric parameters and the load are treated as probabilistic. The results for short columns show that the rate of decrease of probability of failure is a maximum with increase in width, while it increased to a maximum with increase in loads, whereas for long columns the length of column had the predominant effect.     

Synthesis of nanostructured copper hexacyanidoferrate and its application in voltammeteric detection of salbutamol

Nanostructured copper hexacyanidoferrate has been synthesized and characterized using elemental analysis, atomic absorption spectroscopy, thermal and infrared spectral studies. The transmission electron microscopic studies of the synthesized material showed that it consisted of irregular oval and rod shaped particles with a size range 70–100 nm. Nanostructured copper hexacyanidoferrate modified glassy carbon electrode was characterized by cyclic voltammetery and nanostructured copper hexacyanidoferrate–carbon nanotube composite material modified glassy carbon electrode has been used for electrocatalytic oxidation of salbutamol. The electrode modified with composite material was found to reduce the peak potential of oxidation of salbutamol by nearly 90 mV.     

Sequential mixing as effective method in the reduction of percolation threshold of multiwall carbon nanotube in poly(methyl methacrylate)/high‐density poly(ethylene)/MWCNT nanocomposites

This work demonstrates sequential heating protocol to be an effective method in the reduction of percolation threshold of multiwall carbon nanotube (MWCNT) in (70/30 w/w) poly(methyl methacrylate) (PMMA)/high‐density poly(ethylene) (HDPE)/MWCNT nanocomposites. Here, the percolation threshold (P_c) value was reduced to 0.08 wt % of MWCNT, which is the lowest among the ever reported values of P_c for the PMMA system. Moreover, a co‐continuous morphology of the minor HDPE phase was evident throughout the major PMMA phase in a highly asymmetric composition (70/30 w/w) of the blend constituents. The AC conductivity as well as the dielectric permittivity values were increased with increase in loading of MWCNT in the nanocomposites. The detailed analysis of electrical and morphological properties is discussed in depth in the article. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40235.     

Silk proteins for biomedical applications: Bioengineering perspectives

Biomaterials of either natural or synthetic origin are used to fabricate implantable devices, as carriers for bioactive molecules or as substrates to facilitate tissue regeneration. For the design of medical devices it is fundamental to use materials characterized by non-immunogenicity, biocompatibility, slow and/or controllable biodegradability, non-toxicity, and structural integrity. The success of biomaterial-derived biodevices tends to be based on the biomimetic architecture of the materials. Recently, proteins from natural precursors that are essentially structural and functional polymers, have gained popularity as biomaterials. The silks produced by silkworms or spiders are of particular interest as versatile protein polymers. These form the basis for diverse biomedical applications that exploit their unique biochemical nature, biocompatibility and high mechanical strength. This review discusses and summarizes the latest advances in the engineering of silk-based biomaterials, focusing specifically on the fabrication of diverse bio-mimetic structures such as films, hydrogels, scaffolds, nanofibers and nanoparticles; their functionalization and potential for biomedical applications.     

Recovery of copper from a surface altered chalcopyrite contained ball mill spillage through bio-hydrometallurgical route

Bioleaching studies for chalcopyrite contained ball mill spillages are very scarce in the literature. We developed a process flow sheet for the recovery of copper metal from surface activated (600 °C, 15 min) ball mill spillage through bio-hydrometallurgical processing route. Bioleaching of the activated sample using a mixed meso-acidophilic bacterial consortium predominantly A. ferrooxidans strains was found to be effective at a lixiviant flow rate of 1.5 L/h, enabling a maximum 72.36% copper recovery in 20 days. Mineralogical as well as morphological changes over the sample surface were seen to trigger the bioleaching efficiency of meso-acidophiles, thereby contributing towards an enhanced copper recovery from the ball mill spillage. The bio-leach liquor containing 1.84 g/L Cu was purified through solvent extraction using LIX 84I in kerosene prior to the recovery of copper metal by electrowinning. Purity of the copper produced through this process was 99.99%.     

Enhancement of thermal properties of polyacrylonitrile by reinforcement of Mg‐Al layered double hydroxide

The in situ polymerization technique was used for synthesis of polyacrylonitrile nanocomposites (PAN/LDH) by reinforcement of different concentrations of Mg‐Al layered double hydroxide (LDH). Molecular interaction between Mg/Al LDH and PAN matrix was studied by Fourier transform infrared spectroscopy. The morphology of PAN/LDH nanocomposite was investigated by field emission scanning electron microscopy. Energy dispersive spectroscopy of nanocomposites were noticed to establish the elemental composition of the composite. High resolution transmission electron microscopy was used to study the nanostructural distribution of LDH with PAN matrix, whereas crystalline patterns were explained by selected area electron diffraction studies. The thermal properties of nanocomposites were studied by thermo‐gravimetric analysis. It was found that, the thermal property of PAN was substantially enhanced due to strong interfacial adhesion of Mg‐Al‐LDH with PAN matrix. Further, it was noticed that the thermal stability of PAN/LDH nanocomposites were increased with increasing concentration of LDH. POLYM. COMPOS., 36:2140–2144, 2015. © 2014 Society of Plastics Engineer     

Green composites based on high‐density polyethylene and Saccharum spontaneum: Effect of filler content on morphology,thermal, and mechanical properties

Here we report the preparation and characterization of a green composite based on high‐density polyethylene and Kaans grass (Saccharum spontaneum). The composites were prepared by conventional melt‐mixing method, using maximum loading of Kaans grass in powder form (KG‐filler) to achieve acceptable range of required properties. Maleic anhydride grafted polyethylene was used as compatibilizer to achieve effective interaction for improved surface adhesion which was confirmed by FT‐IR spectroscopy. Morphological studies revealed good interaction between the base polymer matrices and the KG‐fillers that improved the mechanical and thermal properties of the composites up to certain (10 phr) KG‐filler loading. Study on water absorption property revealed moderate increase in weight at higher KG‐filler loadings. Thermogravimetric analysis (TGA) and melt flow index (MFI) studies indicated retention of thermal stability and flow property of the HDPE/KG‐filler composite at lower filler loadings. POLYM. COMPOS., 36:2157–2166, 2015. © 2014 Society of Plastics Engineers     

Reduction of percolation threshold of multiwall carbon nanotube (MWCNT) in polystyrene (PS)/low‐density polyethylene (LDPE)/MWCNT nanocomposites: An eco‐friendly approach

In this article, we introduce an eco‐friendly approach to achieve electrical conductivity at sufficiently lower loading of MWCNT in the PS/LDPE/MWCNT nanocomposites through judicious control of temperature during melt blending. The percolation threshold was achieved at 0.21 wt% of MWCNT following this method, which is lower, compared to the result obtained from direct mixing as well as the previously reported data. The morphological analysis revealed a co‐continuous structure of the (70/30, PS/LDPE)/MWCNT nanocomposites in such a high asymmetric composition of blend constituents, which facilitates in the lowering of percolation threshold through selective dispersion of MWCNT in the minor LDPE phase. The electron conduction in the nanocomposites has well been explained in terms of tunneling mechanism, supporting thin coating of polymer over individual CNTs. The morphological, electric and dielectric properties have been well explained in this article. POLYM. COMPOS., 36:1574–1583, 2015. © 2014 Society of Plastics Engineers     

Modulatory Effects of Biosynthesized Gold Nanoparticles Conjugated with Curcumin and Paclitaxel on Tumorigenesis and Metastatic Pathways—In Vitro and In Vivo Studies

Background: Breast cancer is the most common cancer in women globally, and diagnosing it early and finding potential drug candidates against multi-drug resistant metastatic breast cancers provide the possibilities of better treatment and extending life. Methods: The current study aimed to evaluate the synergistic anti-metastatic activity of Curcumin (Cur) and Paclitaxel (Pacli) individually, the combination of Curcumin–Paclitaxel (CP), and also in conjugation with gold nanoparticles (AuNP–Curcumin (Au-C), AuNP–Paclitaxel (Au-P), and AuNP–Curcumin–Paclitaxel (Au-CP)) in various in vitro and in vivo models. Results: The results from combination treatments of CP and Au-CP demonstrated excellent synergistic cytotoxic effects in triple-negative breast cancer cell lines (MDA MB 231 and 4T1) in in vitro and in vivo mouse models. Detailed mechanistic studies were performed that reveal that the anti-cancer effects were associated with the downregulation of the expression of VEGF, CYCLIN-D1, and STAT-3 genes and upregulation of the apoptotic Caspase-9 gene. The group of mice that received CP combination therapy (with and without gold nanoparticles) showed a significant reduction in the size of tumor when compared to the Pacli alone treatment and control groups. Conclusions: Together, the results suggest that the delivery of gold conjugated Au-CP formulations may help in modulating the outcomes of chemotherapy. The present study is well supported with observations from cell-based assays, molecular and histopathological analyses.     

Ternary MOF‑Based Redox Active Sites Enabled 3D‑on‑2D Nanoarchitectured Battery‑Type Electrodes for High‑Energy‑Density Supercapatteries

Designing rationally combined metal-organic frameworks(MOFs)with multifunctional nanogeometries is of significant research interest to enable the electrochemical properties in advanced energy storage devices.Herein,we explored a new class of binderfree dual-layered Ni-Co-Mn-based MOFs(NCM-based MOFs)with three-dimensional(3D)-on-2D nanoarchitectures through a polarityinduced solution-phase method for high-performance supercapatteries.The hierarchical NCM-based MOFs having grown on nickel foam exhibit a battery-type charge storage mechanism with superior areal capacity(1311.4μAh cm^−2 at 5 mA cm^−2),good rate capability(61.8%;811.67μAh cm^−2 at 50 mA cm^−2),and an excellent cycling durability.The superior charge storage properties are ascribed to the synergistic features,higher accessible active sites of dual-layered nanogeometries,and exalted redox chemistry of multi metallic guest species,respectively.The bilayered NCM-based MOFs are further employed as a battery-type electrode for the fabrication of supercapattery paradigm with biomass-derived nitrogen/oxygen doped porous carbon as a negative electrode,which demonstrates excellent capacity of 1.6 mAh cm^−2 along with high energy and power densities of 1.21 mWh cm^−2 and 32.49 mW cm^−2,respectively.Following,the MOF-based supercapattery was further assembled with a renewable solar power harvester to use as a self-charging station for various portable electronic applications.