Improved magneto-electric response in Na0.5Bi0.5TiO3–MnFe2O4 composites

Magneto-electric composites comprising Na_0.5Bi_0.5TiO₃ (NBT) and MnFe₂O₄ (MFO) were fabricated using their fine powders obtained via sol–gel method. X-ray diffraction and scanning electron microscopy results confirmed the single-phase formation of NBT and MFO and the composite nature when these were mixed and sintered at appropriate temperatures. The dielectric constant (ε_r) and dielectric loss (D) decreased with increase in frequency (40–110 MHz). Room temperature magnetization measurements established these composites to be soft magnetic. Further, the nature of these composites were established to be magneto-electric at 300 K. The highest ME response of 0.19 % was observed in 30NBT–70MFO composite. The ME coefficient (α) was 240 mV/cm Oe for the same composition. The present study demonstrated the effectiveness of NBT/MFO as a lead-free multiferroic composite and provides an alternative for environment-friendly ME device applications.     

Assessment of MetOp-A Advanced Very High Resolution Radiometer (AVHRR) short-wave infrared channel measurements using Infrared Atmospheric Sounding Interferometer (IASI) observations and line-by-line radiative transfer model simulations

MetOp-A satellite-based hyper-spectral Infrared Atmospheric Sounding Interferometer (IASI) observations are used to evaluate the accuracy of the broadband short-wave infrared (SWIR) atmospheric window channel (channel 3B) centred at 3.74 μm of the Advanced Very High Resolution Radiometer (AVHRR) carried on the same platform. To complement the partial spectral coverage of IASI, line-by-line radiative transfer model (LBLRTM)-simulated IASI spectra are used. The comparisons result in significant negative AVHRR minus IASI bias in radiance (～–0.04 mW m^–2 sr^–1 cm^–1) with scene temperature dependency in which the absolute value of the bias linearly increases with increasing temperature. It is demonstrated that the negative bias and the scene temperature dependency of the bias are the results of significant absorption in the portion of AVHRR spectral band not seen by IASI, leading to the conclusion that MetOp-A AVHRR channel 3B is not purely an ‘atmospheric window’ channel.     

Plant Pollen Grains: A Move Towards Green Drug and Vaccine Delivery Systems

Pollen grains and plant spores have emerged as innovative biomaterials for various applications such as drug/vaccine delivery, cata-lyst support, and the remova...     

Boron phosphide films prepared by co-evaporation technique: Synthesis and characterization

We report the physical and electronic properties of BP films of 1:1, 1:1.15 and 1.25:1 stoichiometry prepared by co-evaporating B and P onto glass and Si (100) substrates. Compositional information was obtained from X-ray photoelectron spectroscopy measurements. Optical studies indicated allowed indirect transition at  2.08 eV. The room temperature photoluminescence peak at  2.01 eV was due to band gap transitions which shifted to higher energy value when recorded at lower temperature. Fourier transformed infrared (FTIR) spectra were dominated by the characteristic peak of the B–P located at  810 cm^− 1 which could be identified as arising due to transverse optical vibration mode (k  0) while the shoulder at  850 cm^− 1 may be due to longitudinal optical (k  0) vibration mode. Other characteristic peaks for B–O, P–O and B–H vibration modes were also present in the FTIR spectra. Characteristic Raman peaks for BP located at  415 cm^− 1 and 806 cm^− 1 were observed in these films.     

Effect of different raw materials on the microwave dielectric properties of Ba2Ti9O20 ceramics

Dibarium nona titanate (Ba₂Ti₉O₂₀) dielectric ceramics have been prepared through solid-state route using raw materials of different origin. The dielectric resonator properties are studied in the microwave frequency region. The impurities in the raw materials drastically affect the microwave dielectric properties of Ba₂Ti₉O₂₀. Presence of TiO₂, which deteriorates the temperature coefficient of resonant frequency can be identified clearly by XRD in the range 40–45° of 2.     

Entropy generation analysis on forced and free convection flow in a vertical porous channel with aligned magnetic field and Navier slip

The entropy generation rate in a vertical porous channel with injection and suction walls and a uniform magnetic field provided at an angle $\xi$ to the flow direction is studied using an analytical perturbation technique in the presence of Navier slip and buoyancy force. The momentum and energy equations were solved for exemplary values of fluid convection's physical characteristics. Important parameters' impacts on adequate numbers are graphically portrayed and conveyed.