Anurag Roy; Sasireka Velusamy; Tapas K. Mallick; Senthilarasu Sundaram
Abstract
Domestic food waste chicken eggshells can produce naturally abundant protein-based eggshell membranes (ESMs), which is used as a less-explored source of sulphur to synthesize hexagonal CdS nanoparticles (NPs) under 365 nm (UVA) light irradiation. The perspective of CdS NPs synthesis in the way of UVA ...
Read More
Domestic food waste chicken eggshells can produce naturally abundant protein-based eggshell membranes (ESMs), which is used as a less-explored source of sulphur to synthesize hexagonal CdS nanoparticles (NPs) under 365 nm (UVA) light irradiation. The perspective of CdS NPs synthesis in the way of UVA light irradiation soakage technique using ESM is distinctive compare to other traditional methods. Various physicochemical methods were employed to validate the formation of CdS NP using ESM assisted process. The obtained NPs exhibit an average particle size of ~5 nm as obtained from the transmission electron microscopy study. The capability of the synthesized CdS NPs was further explored in the catalysis reaction for the decomposition of KMnO4, considered as toxic Mn VII (violet) ion source at room temperature. The degradation results as monitored by UV-Vis spectrophotometry analysis confirms the CdS NPs exhibit excellent catalytic activity towards the reduction of KMnO4, toxic Mn VII (violet) ion to MnO2 as non-toxic Mn IV (brownish yellow) ion in aqueous solution (pH 7.0) at room temperature by 50 min. The KMnO4 decomposition reaction follows a pseudo-first-order reaction having the rate constant value of 1.9 x 10 -2 min -1 . This study encourages the potential use of natural waste materials for wastewater treatment.
Ragini Singh;Sanjay Singh
Abstract
Nanomaterials (NMs) have found extensive commercial use in industries, healthcare and household applications however, their ecotoxicological effects remain elusive. Since, microbial communities play beneficial role in ecosystem like element cycling, bioremediation, nitrogen fixation, etc., effect of ...
Read More
Nanomaterials (NMs) have found extensive commercial use in industries, healthcare and household applications however, their ecotoxicological effects remain elusive. Since, microbial communities play beneficial role in ecosystem like element cycling, bioremediation, nitrogen fixation, etc., effect of NMs over beneficial microbe’s physiology and viability remains to be studied in detail. Some beneficial microbe communities are severely affected by the release of NMs in the environment. Deinococcus radiodurans is known for its tolerance to oxidative stress caused due to irradiation. In this study, we have used metal, metal oxides, quantum dots (QDs) and carbon based NMs to assess their effect on the cell viability, uptake and ROS generation in D. radiodurans cells. The present study demonstrates in real-time by flow cytometry the internalization of different metal, metal oxide, QDs and carbon based NMs in D. radiodurans. Results show that all the tested NMs are significantly internalized in to the bacterial cells however, carbon based NMs exhibited highest internalization. Toxicity studies revealed that AgNPs exhibited maximum toxicity and reactive oxygen species (ROS) generation followed by QDs, CuO NPs and GO but, AuNPs and TiO2 NPs shows no toxic response in bacterial cells. The oxidative stress and uptake studies will provide insight about the mechanism of oxidative stress tolerance of D. radiodurans.
Yuliya Li; Svetlana Barannikova; Lev Zuev
Abstract
The aim of this contribution was to study the localization of the plastic deformation of bi-metal based on a low-carbon steel A 283 Grade C and austenitic stainless steel 301 AISI. The images of the localized zone plastic deformation upon the uniaxial tension have been obtained with using digital image ...
Read More
The aim of this contribution was to study the localization of the plastic deformation of bi-metal based on a low-carbon steel A 283 Grade C and austenitic stainless steel 301 AISI. The images of the localized zone plastic deformation upon the uniaxial tension have been obtained with using digital image correlation method (DIC). The stress-strain curves are found to show all the plastic flow stages: yield plateau, linear and parabolic work hardening stages and the prefracture stage would occur for the respective values of the exponent from the Ludwik-Holomon equation. The main parameters of plastic flow localization at various stages of the deformation hardening have been determined in bi-metal.
Thomas Qureishy; Yue Zhao; Yan Xu
Abstract
Magneto-optical imaging of YBa2Cu3O7-δ films with high critical current density, synthesized by a cost-effective metal organic decomposition technique reveals inhomogeneous flux penetration in the specimens in the form of thin parallel lines. The origin of such a stripy pattern and its dependence ...
Read More
Magneto-optical imaging of YBa2Cu3O7-δ films with high critical current density, synthesized by a cost-effective metal organic decomposition technique reveals inhomogeneous flux penetration in the specimens in the form of thin parallel lines. The origin of such a stripy pattern and its dependence on the sample preparation conditions and state of substrate is discussed. The stripes reflect accumulation of planar defects forming parallel lines of reduced in-plane critical current density, jc, perpendicular to planar defects and enhanced jc parallel to them. Such channel-like reduction and corresponding enhancement of jc is especially expressed in a sample deposited on vicinal substrate, which, as a consequence, demonstrates global temperature-dependent in-plane anisotropy with an anisotropy ratio up to 2.4. The directional enhancement of critical current density due to planar defects could be beneficial for practical use of superconducting films.
Mete Bakir; Iwona Jasiuk
Abstract
Covetics are a novel class of metal-carbon nanomaterials. The covetics are fabricated using a conventional induction furnace wherein an electric current is applied into an activated carbon infused molten metal medium. In situ generated arc discharge induces a chemical conversion reaction where the amorphous ...
Read More
Covetics are a novel class of metal-carbon nanomaterials. The covetics are fabricated using a conventional induction furnace wherein an electric current is applied into an activated carbon infused molten metal medium. In situ generated arc discharge induces a chemical conversion reaction where the amorphous carbon attains a crystalline structure and forms covalent bonding with host metal matrix. Such fabrication approach also promotes higher carbon solubility in the molten metal than that in traditional metal-carbon alloys. Nanoscale structure analyses revealed single-phase carbon-metal lattice morphologies in the covetics. The covetics have also been shown to possess improved thermos-physical properties as compared to their parent metals. We herein present a review of the literature on the covetics. First, we introduce the covetic materials, and then provide a brief overview on metal-carbon nanocomposites. Then, we summarize experimental results on covetics. Finally, we discuss characterization challenges and future directions in the covetics research.
Jai Prakash; A. Tripathi; G. B. V. S. Lakshmi; V. Rigato; Jalaj Tripathi; D. K. Avasthi
Abstract
Thin metal films of Ag (~10 nm) deposited on spin coated PVC film on quartz substrate, were irradiated with 150 keV Ar ions at fluences varying from 5×10 15 to 5×10 16 ions/cm 2 and characterized with Rutherford backscattering spectrometry (RBS), atomic force microscopy (AFM), scanning electron ...
Read More
Thin metal films of Ag (~10 nm) deposited on spin coated PVC film on quartz substrate, were irradiated with 150 keV Ar ions at fluences varying from 5×10 15 to 5×10 16 ions/cm 2 and characterized with Rutherford backscattering spectrometry (RBS), atomic force microscopy (AFM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) techniques. RBS spectra show sputtering of the Ag film. As a result of ion irradiation, isolated Ag nanoparticles are formed on the surface. The size and size distribution of Ag nanoparticles are found to be dependent on ion fluence. Contact angle measurements were carried out to study the hydrophilic nature of the surface at varying fluences. Results are explained in the framework of sputtering from the surface due to dense collision cascade resulting from Ar ion and Ag/PVC film interaction.
Jai Prakash; A. Tripathi; J.C. Pivin; Jalaj Tripathi; A.K. Chawla; Ramesh Chandra; S.S. Kim; K. Asokan; D.K. Avasthi
Abstract
The present work envisages synthesis of magnetic nanocomposites by ion beam mixing technique using swift heavy ion irradiation of Ni-Teflon bilayer system and its magnetic characterizations. The nanocomposite is characterized by Rutherford backscattering spectrometry (RBS), transmission electron microscopy ...
Read More
The present work envisages synthesis of magnetic nanocomposites by ion beam mixing technique using swift heavy ion irradiation of Ni-Teflon bilayer system and its magnetic characterizations. The nanocomposite is characterized by Rutherford backscattering spectrometry (RBS), transmission electron microscopy (TEM), scanning probe microscopy (SPM) and superconducting quantum interference device (SQUID) magnetometer. Cross-sectional TEM and magnetic force microscopy (MFM) results confirm the formation of nanocomposite. Magnetic characterizations reveal that nanocomposite exhibits ferromagnetic behavior with an increase in the coercivity, which is attributed to the formation of Ni nanoparticles. The coercivity of the nanocomposite is found to be 112 Oe at room temperature which is two orders of magnitude larger than that of the bulk Ni (0.87 Oe).