Piezoresistive sensors based on electrospun mats modified by 2D Ti3C2Tx MXene

The preparation methodology and properties of electroconductive, electrospun mats composed of copolyamide 6,10 and Ti3C2Tx are described in this paper. Mats of several compositions were prepared from a solution of n-propanol. The obtained electrospun mats were then tested as piezoresistive sensors. The relative resistance (AR) of the sensor increased with an increase in the Ti3C2Tx content, and materials with relatively higher electrical conductivity displayed noticeably higher sensitivity to applied pressure. The pressure-induced changes in resistivity increased with an increment in the applied force. - 2019 by the authors. Licensee MDPI, Basel, Switzerland.Funding: This publication was supported by Qatar University Collaborative High Impact Grant QUHI-CENG-18/19-1. The findings accomplished here in are solely the responsibility of the authors.Scopu

Electrically conductive electrospun polymeric mats for sensing dispersed vegetable oil impurities inwastewater

This paper addresses the preparation of electrically conductive electrospun mats on a base of styrene-isoprene-styrene copolymer (SIS) and multiwall carbon nanotubes (CNTs) and their application as active sensing elements for the detection of vegetable oil impurities dispersed within water. The most uniform mats without beads were prepared using tetrahydrofuran (THF)/ dimethyl formamide (DMF) 80:20 (v/v) as the solvent and 13 wt. % of SIS. The CNT content was 10 wt. %, which had the most pronounced changes in electrical resistivity upon sorption of the oil component. The sensors were prepared by deposition of the SIS/CNT layer onto gold electrodes through electrospinning and applied for sensing of oil dispersed in water for 50, 100, and 1000 ppm. - 2019 by the authors.This publication was supported by the Qatar University Collaborative Grant QUCG-CAM-19/20-2. The findings achieved herein are solely the responsibility of the authors. The publication of this article was funded by the Qatar National Library.Scopu

Sunlight-Driven Combustion Synthesis of Defective Metal Oxide Nanostructures with Enhanced Photocatalytic Activity

Synthesis of metal oxide nanostructures through combustion routes is a promising technique owing to its simplicity, rapidity, scalability, and cost-effectiveness. Herein, a sunlight-driven combustion approach is developed to synthesize pristine metal oxides and their heterostructures. Sunlight, a sustainable energy source, is used not only to initiate the combustion reaction but also to create oxygen vacancies on the metal oxide surface. ZnO nanostructures are successfully synthesized using this novel approach, and the products exhibit higher photocatalytic activity in the decomposition of methyl orange (MO) than ZnO nanostructures synthesized by the conventional methods. The higher photocatalytic activity is due to the narrower band gap, higher porosity, smaller and more uniform particle size, surface oxygen vacancies, as well as the enhanced exciton dissociation efficiency induced by the sunlight. Porous Fe3O4 nanostructures are also prepared using this environmentally benign method. Surprisingly, few-layer Bi2O3 nanosheets are successfully obtained using the sunlight-driven combustion approach. Moreover, the approach developed here is used to synthesize Bi2O3/ZnO heterostructure exhibiting a structure of few-layer Bi2O3 nanosheets decorated with ZnO nanoparticles. Bi2O3 nanosheets and Bi2O3/ZnO heterostructures synthesized by sunlight-driven combustion route exhibit higher photocatalytic activity than their counterparts synthesized by the conventional solution combustion method. This work illuminates a potential cost-effective method to synthesize defective metal oxide nanostructures at scale. Copyright - 2019 American Chemical Society.This study was supported by University Grants Commission, India, under University with Potential for Excellence (UPE) program at University of Mysore, UGC JRF (Award No. F.19-1/2013(SA-I)), and Deanship of Scientific Research (DSR) at King Fahd University of Petroleum & Minerals (KFUPM) through project no. DF181021.Scopu

A scrutiny of antibacterial activity of pure and iodine doped ZnO thin films synthesized by mSILAR method

Iodine doped zinc oxide (I-ZnO) thin films were synthesized by microwave assisted successive ionic layer adsorption (mSILAR) method. The structural characteristics of pure ZnO and I-ZnO thin films were carried out by powder X-ray diffraction (PXRD) analysis. The potential toxicity of pure and I-ZnO films was examined against gram-positive species like Staphylococcus aureus, Streptococcus haemolyticus and Bacillus cereus as well as gram-negative species like Escherichia coli, Klebsiella pneumonia, Proteus vulgaris, Pseudomonas aeruginosa, Salmonella typhi, Serratia marcescens, Proteus rettigiri and Vibrio cholera by employing disc diffusion method. All the samples exhibited antibacterial activity on the tested organisms. I-ZnO produced maximum activity against both gram-positive and gram-negative species compared with pure ZnO thin film. The gram-positive species were observed to be more resistant to pure and I-ZnO thin films than gram-negative species. The studies revealed an enhancement in antibacterial activity of the I-doped thin films as compared to pure ZnO thin films. - 2019 Author(s).Scopu

Various techniques to enhance distillate output of tubular solar still: A review

The necessity of freshwater is rising due to the expanding residents as well as fast urbanization. Besides, concerning the drinking purpose, clean water represents a very crucial role in several applications like batteries, pharmaceuticals, automobiles and different research and development laboratories. There are many freshwater generation techniques available, but solar distillation is one of the most natural and cheapest methods. Present review paper exhibits the researchers work on the tubular solar still to enhance the distillate output. It covers the working principle and several metrological parameters like the temperature of the water, solar intensity, glass cover temperature etc. Various techniques to improve the distillate output of tubular solar still also included in the present review paper. At last, several future researches works on tubular solar still also included in this review paper. - 2019 Elsevier B.V.Scopu

A comparative review of natural and synthetic biopolymer composite scaffolds

Tissue engineering (TE) and regenerative medicine integrate information and technology from various fields to restore/replace tissues and damaged organs for medical treatments. To achieve this, scaffolds act as delivery vectors or as cellular systems for drugs and cells; thereby, cellular material is able to colonize host cells sufficiently to meet up the requirements of regeneration and repair. This process is multi-stage and requires the development of various components to create the desired neo-tissue or organ. In several current TE strategies, biomaterials are essential components. While several polymers are established for their use as biomaterials, careful consideration of the cellular environment and interactions needed is required in selecting a polymer for a given application. Depending on this, scaffold materials can be of natural or synthetic origin, degradable or nondegradable. In this review, an overview of various natural and synthetic polymers and their possible composite scaffolds with their physicochemical properties including biocompatibility, biodegradability, morphology, mechanical strength, pore size, and porosity are discussed. The scaffolds fabrication techniques and a few commercially available biopolymers are also tabulated.Scopu

Analysis of wear behavior and surface properties of detonation gun-sprayed composite coating of Cr3C2–NiCr–CeO2 on boron steel

The present paper reports the analysis of wear behavior and surface properties of detonation gun-sprayed composite coating of chromium carbide–nichrome–cerium oxide (Cr3C2–NiCr–CeO2) on boron steel. Experiments were performed to have complete understanding of wear rate and volume loss for the worn out surfaces. X-ray diffraction and scanning electron microscopy analysis were used for phase detection and microstructural characterization. Addition of rare earth metal improves the stickiness and avoids corrosion in the coating. Pin on disc test rig was used for the experimental purpose, and wear rate was calculated at three loads (30 N, 60 N and 90 N) in both dry and lubricating conditions. These tests were done for different cycles (to completely understand the wear behavior). From the results, it could be concluded that in lubrication state when the applied load is less, Cr3C2–NiCr+10% CeO2 coated sample shows the better result as compared to Cr3C2–NiCr+5% CeO2 and uncoated samples.Scopu

Experimental investigation on the thermal properties of NiO-nanofluids

Performance parameters and thermal stability of lubricants are highly temperature dependent as it degrades twice for every 10 °C of temperature rise. Generally, the nanofluids have enhanced thermo-physical behavior as long as the nanoparticles are homogeneously dispersed and thermally stable. Therefore, the investigation of thermal characteristics of nanofluids may reveal their suitability in the temperature dependent applications. In the present study, NiO nanocrystalline (72.97 nm) flakes are prepared by sol–gel method and dispersed in SN500 lubricant oil for optimizing the thermal properties. The NiO-nanofluids are formulated by two-step method and their thermal properties are estimated from ambient temperature to 1000 °C. The addition of NiO nanoparticles (0.1 wt%, 0.3 wt.% and 0.5 wt.%) in the lubricant enhances the ability to resist thermal decomposition, which is enriched from 49 °C to 210 °C, 222 °C and 247 °C, respectively.Scopu

Evolution from graphite to graphene elastomer composites

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Cisplatin-Loaded Graphene Oxide/Chitosan/Hydroxyapatite Composite as a Promising Tool for Osteosarcoma-Affected Bone Regeneration

Presently, tissue engineering approaches have been focused toward finding new potential scaffolds with osteoconductivity on bone-disease-affected cells. This work focused on the cisplatin (CDDP)-loaded graphene oxide (GO)/hydroxyapatite (HAP)/chitosan (CS) composite for enhancing the growth of osteoblast cells and prevent the development of osteosarcoma cells. The prepared composites were characterized for the confirmation of composite formation using Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and X-ray diffraction techniques. A flowerlike morphology was observed for the GO/HAP/CS-3/CDDP composite. UV-vis spectroscopy was used to observe the controlled release of CDDP from the GO/HAP/CS-3/CDDP composite, and 67.34% of CDDP was released from the composite over a time period of 10 days. The GO/HAP/CS-3/CDDP nanocomposites showed higher viability in comparison with GO/HAP/CS-3 on MG63 osteoblast-like cells and higher cytotoxicity against cancer cells (A549). The synthesized composite was found to show enhanced proliferative, adhesive, and osteoinductive effects on the alkaline phosphatase activity of osteoblast-like cells. Our results suggested that the CDDP-loaded GO/HAP/CS-3 nanocomposite has an immense prospective as a bone tissue replacement in the bone-cancer-affected tissues.Funding M.R. acknowledges major financial support from the Department of Science and Technology, Science and Engineering Research Board (ref YSS/2015/001532; New Delhi, India) and also acknowledges the DST-PURSE program for the purchase of SEM and FTIR and UPE programs for the purchase of TEM. Notes The authors declare no competing financial interest.Scopu