Microwave-Assisted High-Energy Ball Milling Synthesis of SBT Nano-Ceramics

Abstract

Non-stoichiometric Sr_0.8Bi_2.15Ta₂O₉ (SBT) ferroelectric nano-ceramic powder was obtained by using high-energy ball milling technique. Calcination and sintering of the obtained SBT nano-powder were optimized at 700?°C for 30?min and 1000?°C for 30?min, respectively in a microwave furnace. XRD study confirmed single-phase orthorhombic structure of SBT ceramics. FESEM micrographs of calcined powder showed particles with size ranging from 60 to 170?nm. High value of ε_r and tanδ at higher temperature is attributed to space charges in the ceramics. Fatigue-free nature up to 10⁹ switching cycles along with high R_sq ～1.98 makes the SBT system suitable for NVFRAM applications.     

Temporal evolution of white light emission from CdSe quantum dots

A study of white light emission from magic sized CdSe quantum dots is reported. Quantum dots were synthesized using a hot solution method and exhibited strong white light with a quantum yield in the range of 10-30%. The emission of white light was attributed to photoluminescence (PL) from both excitons and surface states. The wavelength and intensity of the PL from both excitons and surface states were found to depend upon the particle size, reaction time, reaction temperature and precursor ratio.     

Earthquake vibration control of structures using hybrid mass liquid damper

A tuned liquid damper (TLD) is a passive vibration control device consisting of a rigid tank filled with water that relies on the sloshing of water inside it to dissipate energy. In a standard TLD configuration the TLD is connected rigidly to the top of the building structure. Earlier research has shown that the TLD is more effective when its base acceleration amplitude is larger, as it dissipates more energy through increased sloshing. This characteristic has been utilized to design this alternate TLD configuration. In this alternate TLD configuration, the TLD is rigidly attached to a secondary mass that is attached to the primary structure through a spring system. This alternate configuration is, thus, defined as a hybrid mass liquid damper (HMLD). For particular values of the secondary spring’s flexibility, the motion of the secondary structure is in phase with that of the primary structure and the TLD base is subjected to a large amplitude acceleration that increases its effectiveness. It should be noted that when the secondary spring is rigid, the alternate and standard TLD configurations are identical for very small values of the secondary mass. It is seen that, for a given structure with HMLD there exists an optimum value of the secondary spring’s stiffness for which the HMLD effectiveness is maximum. An optimally designed HMLD configuration is shown to be more effective as a control device than the standard TLD configuration for both harmonic and broad-band earthquake motions.     

Preparation of nano-sized ABi2Nb2O9 (A?=?Ca2+, Sr2+, Ba2+) ferroelectric ceramics by soluble Nb(V) tartarate precursor and their dielectric characteristics after sintering

ABi₂Nb₂O₉ (A = Ca²⁺, Sr²⁺, Ba²⁺) were prepared by using an aqueous solution method from the mixture of water-soluble M-EDTA (M = Ca²⁺, Sr²⁺, Ba²⁺), Bi-EDTA, Nb-tartarate and TEA as the starting materials. A black fluffy mass resulted on heating the solution mixture at ∼200 °C. X-ray powder diffraction (XRD) showed that a single phase with the layered perovskite structure was formed after calcining the black fluffy mass at 600 °C. No intermediate phase was found during heat treatment at and above 600 °C. The particle size obtained from TEM lay between 20 and 30 nm. Structural electron microscopy (SEM) revealed that the average grain size after sintering at 900 °C for 4 h ranges from 1.2 to 1.67 μm with a relative compact density of ≥90%. A comparative study on dielectric constant and corresponding tangent loss were carried out at 1 kHz, 100 kHz, 1 MHz, and 5 MHz from which the Curie temperature (T _c) was found to be at 935, 450, and 170 °C with peak dielectric constants at 930, 595, and 545, respectively, for CBN (CaBi₂Nb₂O₉), SBN (SrBi₂Nb₂O₉), and BBN (BaBi₂Nb₂O₉) measured at frequency 100 kHz with very low tangent loss.     

Green Synthesis of Endolichenic Fungi Functionalized Silver Nanoparticles: The Role in Antimicrobial,Anti-Cancer,and Mosquitocidal Activities

Green nanotechnology is currently a very crucial and indispensable technology for handling diverse problems regarding the living planet. The concoction of reactive oxygen species (ROS) and biologically synthesized silver nanoparticles (AgNPs) has opened new insights in cancer therapy. The current investigation caters to the concept of the involvement of a novel eco-friendly avenue to produce AgNPs employing the wild endolichenic fungus Talaromyces funiculosus. The synthesized Talaromyces funiculosus–AgNPs were evaluated with the aid of UV visible spectroscopy, dynamic light scattering (DLS), Fourier infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The synthesized Talaromyces funiculosus–AgNPs (TF-AgNPs) exhibited hemo-compatibility as evidenced by a hemolytic assay. Further, they were evaluated for their efficacy against foodborne pathogens Staphylococcus aureus, Streptococcus faecalis, Listeria innocua, and Micrococcus luteus and nosocomial Pseudomonas aeruginosa, Escherichia coli, Vibrio cholerae, and Bacillus subtilis bacterial strains. The synthesized TF-AgNPs displayed cytotoxicity in a dose-dependent manner against MDA-MB-231 breast carcinoma cells and eventually condensed the chromatin material observed through the Hoechst 33342 stain. Subsequent analysis using flow cytometry and fluorescence microscopy provided the inference of a possible role of intracellular ROS (OH⁻, O⁻, H₂O₂, and O₂⁻) radicals in the destruction of mitochondria, DNA machinery, the nucleus, and overall damage of the cellular machinery of breast cancerous cells. The combined effect of predation by the cyclopoid copepod Mesocyclops aspericornis and TF-AgNPS for the larval management of dengue vectors were provided. A promising larval control was evident after the conjunction of both predatory organisms and bio-fabricated nanoparticles. Thus, this study provides a novel, cost-effective, extracellular approach of TF-AgNPs production with hemo-compatible, antioxidant, and antimicrobial efficacy against both human and foodborne pathogens with cytotoxicity (dose dependent) towards MDA-MB-231 breast carcinoma.     

Exergetic optimization of solar water collectors using computational intelligence techniques

Clean Technologies and Environmental Policy - This article proposes a model to determine the optimal performance and design conditions for a flat plate solar water collector. The model uses the...     

Peracetic acid bleaching of banana fibre: Process optimisation

Banana is an important commercially available natural fibre, suitable for making coarse yarns. It has also potential for making fine home and apparel textiles after requisite chemical intervention or blending with other fine fibres. For making such products, chemical processing, namely bleaching, coloration and finishing, play an important role. Bleaching of fibre is generally carried out in highly alkaline condition and at high temperature of 85°C using hydrogen peroxide to achieve whiteness index of > 70 with about 25% loss in tensile strength. To achieve a similar whiteness index, while addressing strength loss, a fibre friendly low-temperature low-alkali based peracetic acid (PAA) bleaching of banana fibre has been proposed in the present article. Important bleaching process parameters, namely PAA concentration (10–30 g/L), time (60–180 min) and temperature (60–80°C), have been varied for optimisation of the bleaching process. Banana fibre bleaching using PAA concentration of 20 g/L at 70°C for 2 h can produce fibre with whiteness index of > 70, which is suitable for subsequent coloration. The PAA bleached banana fibre can retain 84% of its bundle strength and 95.6% of its weight. Physical (strength, fineness), chemical (attenuated total reflectance Fourier-transform infrared [ATR-FTIR], energy dispersive X-ray spectroscopy [EDX]), optical (colour) and morphological (scanning electron microscopy [SEM]) properties of banana fibres before and after bleaching were evaluated to study the efficacy of the process.     

Design and Investigation of Split Gate Dielectric Modulated JLFET for Detection of Biological Molecule Using TCAD Simulation

Silicon - Here, a split gate insulator-controlled Junction less FET also known as SG-DM-JLFET is investigated and proposed to recognize biomolecules such as uricase, biotin, or aminopropyl-...     

An Ensemble Based Approach for Sentiment Classification in Asian Regional Language

In today’s digital world, millions of individuals are linked to one another via the Internet and social media. This opens up new avenues for information exchange with others. Sentiment analysis (SA) has gotten a lot of attention during the last decade. We analyse the challenges of Sentiment Analysis (SA) in one of the Asian regional languages known as Marathi in this study by providing a benchmark setup in which we first produced an annotated dataset composed of Marathi text acquired from microblogging websites such as Twitter. We also choose domain experts to manually annotate Marathi microblogging posts with positive, negative, and neutral polarity. In addition, to show the efficient use of the annotated dataset, an ensemble-based model for sentiment analysis was created. In contrast to others machine learning classifier, we achieved better performance in terms of accuracy for ensemble classifier with 10-fold cross-validation (cv), outcomes as 97.77%, f-score is 97.89%.     

Host-Assisted Delivery of a Model Drug to Genomic DNA: Key Information from Ultrafast Spectroscopy and in silico Study

Drug delivery to a target without adverse effects is one of the major criteria for clinical use. Herein, we have made an attempt to explore the delivery efficacy of SDS surfactant in a monomer and micellar stage during the delivery of the model drug, Toluidine Blue (TB) from the micellar cavity to DNA. Molecular recognition of pre-micellar SDS encapsulated TB with DNA occurs at a rate constant of k₁ ∼652 s⁻¹. However, no significant release of encapsulated TB at micellar concentration was observed within the experimental time frame. This originated from the higher binding affinity of TB towards the nano-cavity of SDS at micellar concentration which does not allow the delivery of TB from the nano-cavity of SDS micelles to DNA. Thus, molecular recognition controls the extent of DNA recognition by TB which in turn modulates the rate of delivery of TB from SDS in a concentration-dependent manner.