A study of a water-reducing agent from cashew nutshell liquid

The water-reducing agent better known as superplasticizer is a recent development. A number of base materials have been used for the development of such water-reducing agents which can act better than ordinary plasticizers in concrete. The sulphonated salts of melamine, napthalene, lignin, hydroxycarboxylic acids and hydroxylated polymers are some typical compounds. Recently cashew nutshell liquid obtained from a natural product waste as a thick black phenolic compound has been converted into a water-reducing agent. This paper describes the results obtained on its effectiveness in influencing the rheological properties of flow, viscosity, particle size distribution, etc, of cement particles in hydrating cements and the water-reducing capabilities in cement mortars and concretes.     

Inactivation of Foodborne Pathogens by NiO/TiO2 Composite Nanofibers: A Novel Biomaterial System

This study presents the fabrication and characterization of novel NiO/TiO₂ composite nanofibers and their antibacterial activity. The utilized NiO/TiO₂ composite nanofibers were prepared by electrospinning of a sol–gel composed of nickel nitrate hexahydrate, titanium isopropoxide and poly(vinyl acetate). The obtained electrospun nanofiberous mat was vacuum dried at 80 °C and then calcined at 600 °C in air for 2 h. The physicochemical properties of the synthesized nanofibers were determined by X-ray diffraction pattern, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, electron probe microanalysis and transmission electron microscopy. The antibacterial activity was tested against four common foodborne pathogenic bacteria viz., Staphylococcus aureus, Escherichia coli, Salmonella typhimurium and Klebsiella pneumoniae by minimum inhibitory concentration (MIC) method taking five different concentrations (5–45 μg/ml). Our investigation reveals that the lowest concentration of NiO/TiO₂ composite solution inhibiting the growth of tested strains was found to be 5 μg/ml. TEM analysis demonstrated that the exposure of the selected microbial strains to the composite nanofibers led to disruption of cell membranes and depressed the activity of some membranous enzymes, which caused bacteria to die eventually. Furthermore, the results illustrate that the combination of NiO and TiO₂ can be synergistic and resulted in superior antimicrobial activity of NiO/TiO₂ composite nanofibers. To sum up, novel NiO/TiO₂ composite nanofibers that possess large surface-to-volume ratio with excellent antimicrobial activity were fabricated that can be used to inhibit the microbial growth associated with food stuff.     

Electron microscopy studies of the thermal stability of gold nanoparticle arrays

A series of monolayer protected gold nanoparticle colloidal solutions have been prepared with average sizes in the 2–15nm range. If a drop of such a colloidal suspension is deposited onto a Si₃N₄ substrate and the solvent allowed to evaporate, the particles have a tendency to self-assemble into monolayer rafts with varying degrees of structural order depending on the initial mono-dispersity of the particles. The thermal stability of these selfassembled gold nanoparticle rafts as a function of particle size, heating method, heating rate and ligand identity have been assessed in this study. In-situ TEM studies show that sub-8nm Au nanoparticles on Si₃N₄ have a tendency to coarsen upon slow heating, whereas those comprised of larger particles exhibit densification. Increasing the heating rate for the smaller particles promoted densification, forcing them to form highly interconnected string-like structures. Finally, rafts of sub-4nm alkanethiol protected Au nanoparticles are shown to sinter spontaneously under ambient conditions at room temperature on the timescale of several months. This unexpected effect may have important implications for the long term structural stability of any device constructed from sub-4nm gold nanoparticles.     

Inactivation of pathogenic Klebsiella pneumoniae by CuO/TiO2 nanofibers: A multifunctional nanomaterial via one-step electrospinning

The fabrication and characterization of one-dimensional CuO/TiO₂ nanofibers with high photocatalytic and antibacterial activities are presented. The CuO/TiO₂ nanofibers were prepared by electrospinning of colloid composed of titanium isopropoxide, poly(vinylpyrroliodine) (PVP) and copper nanoparticles and calcination at 700 °C in air for 1 h. The antibacterial activity was tested using Klebsiella pneumoniae as model organism by calculation of the minimum inhibitory concentration (MIC). The obtained CuO/TiO₂ nanofibers showed prominent photocatalytic activity under visible light to degrade reactive black5 and reactive orange16 dyes in aqueous solutions and effectively catalyze K. pneumoniae inactivation. The decomposition process of the cell wall and cell membrane was directly observed by TEM analysis after the exposure of the K. pneumoniae to the nanofibers. Interestingly, the introduced photocatalyst can be reused with the same photocatalytic activity. Overall, the combination of CuO and TiO₂ can be synergistic and resulted in CuO/TiO₂ composite nanofibers having superior photocatalytic and antimicrobial potential to impede K. pneumoniae growth which causes bacterium to die ultimately.     

Exploring Regional Profile of Drought History- a New Procedure to Characterize and Evaluate Multi-Scaler Drought Indices Under Spatial Poisson Log-Normal Model

Water Resources Management - Drought is recurrently occurring in many parts of the globe. In contrast to other natural hazards, drought has complex climatic characteristics. Several environmental...     

A Unified Decision-Making Technique for Analysing Treatments inPandemicContext

The COVID-19 pandemic has triggered a global humanitarian disaster that has never been seen before. Medical experts, on the other hand, are undecided on the most valuable treatments of therapy because people ill with this infection exhibit a wide range of illness indications at different phases of infection. Further, this project aims to undertake an experimental investigation to determine which treatments for COVID-19 disease is the most effective and preferable. The research analysis is based on vast data gathered from professionals and research journals, making this study a comprehensive reference. To solve this challenging task, the researchers used the HF AHP-TOPSIS Methodology, which is a well-known and highly effective Multi-Criteria Decision Making (MCDM) technique. The technique assesses the many treatment options identified through various research papers and guidelines proposed by various countries, based on the recommendations of medical practitioners and professionals. The review process begins with a ranking of different treatments based on their effectiveness using the HF-AHP approach and then evaluates the results in five different hospitals chosen by the authors as alternatives. We also perform robustness analysis to validate the conclusions of our analysis. As a result, we obtained highly corroborative results that can be used as a reference. The results suggest that convalescent plasma has the greatest rank and priority in terms of effectiveness and demand, implying that convalescent plasma is the most effective treatment for SARS-CoV-2 in our opinion. Peepli also has the lowest priority in the estimation.     

Boosted hydrogen evolution activity from Sr doped ZnO/CNTs nanocomposite as visible light driven photocatalyst

CNTs were decorated onto Sr doped ZnO nanoparticles to construct an efficient photocatalyst via a facile sol-gel method. The as-fabricated Sr doped ZnO/CNTs with recyclability exhibits Sr and CNTs content dependent hydrogen evolution activit under visible light illumination. The Sr doped ZnO/CNTs photocatalyst shows the highest hydrogen evolution rate of 2732.2 μmolh^?1g^?1, which is 33.7 and 2.83 times higher than pure ZnO and Sr doped ZnO photocatalysts, respectively. The improved hydrogen evolution activity of Sr doped ZnO/CNTs is primarily assigned to high surface area, Sr doping and construction of heterojunction, which can extend the light absorption, decrease the optical band gap and improve the charge separation. Moreover, the underlying photocatalytic mechanism is proposed on the basis of Mott-Schottky study and explains the interfacial charge transfer process from ZnO to CNTs and Sr. This work open new strategies to synthesize CNTs based nanocomposite for hydrogen evolution.