Bandwidth and frequency agile MIMO antenna for cognitive vehicular communications

A reconfigurable MIMO antenna for heterogeneous vehicular networks is reported in this paper. The frequency and bandwidth characteristics of the MIMO antenna can be reconfigured to meet multi-standard and multi-frequency requirements in automobiles. The antenna element evolved from an edge-chamfered ultra-wideband (UWB) antenna operating from 2.1 to >15 GHz. The bandwidth reconfiguration is achieved through the selection of excitation paths connecting the feed and radiator. The feedline selection is performed using PIN diodes, making the antenna operate in three distinct modes, namely, UWB mode (Mode 1: 2.1–>15 GHz), industrial, scientific and medical/Internet of Things (ISM/IoT) mode (Mode 2: 2.45 GHz), and wireless local area network (WLAN) mode (Mode 3: 5–6 GHz). The feed path corresponding to Mode 2 and Mode 3 is incorporated with a suitable filtering network to shape the frequency response of the antenna based on the user's requirements. Owing to the requirement of cognitive selection of frequency bands, the frequency tunability in Mode 2 is realized using varactor diodes. The varactor-incorporated feed path reconfigures the center frequency between 2.45 and 3.5 GHz. The proposed MIMO antenna offers gain and total efficiency greater than 2.94 dBi and 76%, respectively. The prototype of the 4-port MIMO antenna is being fabricated to test its functionality in real time.     

RES‐loaded pegylated CS NPs: for efficient ocular delivery

The objective of this study is to develop resveratrol (RES) loaded polyethylene glycols (PEGs) modified chitosan (CS) nanoparticles (NPs) by ionic gelation method for the treatment of glaucoma. While increasing the concentration of PEG, the particle size and polydispersity index of the formulations increased. Entrapment efficiency and RES loading (RL) of NPs decreased while increasing PEG concentration. The in vitro release of NPs showed an initial burst release of RES (45%) followed by controlled release. Osmolality of formulations revealed that the prepared NPs were iso‐osmolar with the tear. Ocular tolerance of the NPs was evaluated using hen''s egg test on the chorioallantoic membrane and it showed that the NPs were non‐irritant. RES‐loaded PEG‐modified CS NPs shows an improved corneal permeation compared with RES dispersion. Fluorescein isothiocyanate loaded CS NPs accumulated on the surface of the cornea but the PEG‐modified CS NPs crossed the cornea and reached retinal choroid. RES‐loaded PEG‐modified CS NPs reduced the intra‐ocular pressure (IOP) by 4.3 ± 0.5 mmHg up to 8 h in normotensive rabbits. These results indicate that the developed NPs have efficient delivery of RES to the ocular tissues and reduce the IOP for the treatment of glaucoma.Inspec keywords: conducting polymers, nanoparticles, nanomedicine, drug delivery systems, particle size, nanofabrication, organic compounds, biomembranes, cellular biophysics, eye, vision defects, biological tissuesOther keywords: RES‐loaded pegylated CS NP, efficient ocular delivery, resveratrol loaded polyethylene glycol modified chitosan nanoparticles, ionic gelation method, glaucoma treatment, particle size, polydispersity index, entrapment efficiency, RES loading, PEG concentration, in vitro release, osmolality formulations, ocular tolerance, hen egg testing, chorioallantoic membrane, improved corneal permeation, RES dispersion, fluorescein isothiocyanate loaded CS NP, cornea surface, reached retinal choroid, intraocular pressure, normotensive rabbits, RES delivery, ocular tissues     

Robust numerical scheme for singularly perturbed convection–diffusion parabolic initial–boundary-value problems on equidistributed grids

In this article, we study the numerical solution of singularly perturbed parabolic convection–diffusion problems exhibiting regular boundary layers. To solve these problems, we use the classical upwind finite difference scheme on layer-adapted nonuniform meshes. The nonuniform meshes are obtained by equidistributing a positive monitor function, which depends on the second-order spatial derivative of the singular component of the solution. The truncation error and the stability analysis are obtained. Parameter-uniform error estimates are derived for the numerical solution. Semilinear IBVPs are also solved. Numerical experiments are carried out to support the theoretical results.     

Phyto‐mediated synthesis,biological and catalytic activity studies of gold nanoparticles

In the present study, a phyto‐mediated synthesis of gold nanoparticles (AuNPs) using an isoflavone, Dalspinosin (5,7‐dihydroxy‐6,3′,4′‐trimethoxy isoflavone) isolated from the alcoholic extract of roots of Dalbergia coromandeliana is reported. It is observed that Dalspinosin itself acts both as a reducing and a capping agent in the synthesis of the nanoparticles (NPs). An ultraviolet–visible (UV–Vis) spectral study showed a surface plasmon resonance band at 526 nm confirming the formation of AuNPs. The NPs formed were characterised by UV–Vis spectroscopy, Fourier transform‐infrared spectroscopy, X‐ray diffraction (XRD), high‐resolution transmission electron microscopy (HR‐TEM) with energy‐dispersive x‐ray spectroscopy (EDX) and dynamic light scattering. HR‐TEM analysis showed the synthesised AuNPs were spherical in shape with a size of 7.5 nm. The AuNPs were found to be stable for seven months when tested by in vitro methods showed good antioxidant and anti‐inflammatory activities. They also showed moderate anti‐microbial activities when tested against Gram positive (Staphylococcus aureus and Streptococcus sp), Gram negative bacterial strains (Klebsiella pneumonia and Klebsiella terrigena) and fungal strain (Candida glabrata). The biosynthesised AuNPs showed significant catalytic activity in the reduction of methylene blue with NaBH₄ to leucomethylene blue.Inspec keywords: biomedical materials, catalysis, Fourier transform infrared spectra, gold, light scattering, microorganisms, nanomedicine, nanoparticles, spectrochemical analysis, surface plasmon resonance, transmission electron microscopy, ultraviolet spectra, visible spectra, X‐ray chemical analysis, X‐ray diffractionOther keywords: phyto‐mediated synthesis, biological activity studies, catalytic activity studies, dalspinosin (5,7‐dihydroxy‐6,3′,4′‐trimethoxy isoflavone), alcoholic extract, roots, Dalbergia coromandeliana, ultraviolet‐visible spectral study, surface plasmon resonance band, UV‐Vis spectroscopy, Fourier transform‐infrared spectroscopy, X‐ray diffraction, high‐resolution transmission electron microscopy, EDX analysis, dynamic light scattering, HR‐TEM analysis, antioxidant activities, antiinflammatory activities, antimicrobial activities, Gram positive bacterial strains, Staphylococcus aureus, Streptococcus sp, Gram negative bacterial strains, wavelength 526 nm, size 7.5 nm, time 7 month, Au     

Electronic transport in thermally grown Cr2O3

Electrical conductivity of thermally grown Cr₂O₃ has been measured as a function of temperature and over a range of oxygen partial pressures from that of air to that of the Cr/Cr₂O₃ equilibrium. The conductivity showed p-type behavior over the range of the present investigation. At temperatures above 1000°C, the conductivity values were independent of oxygen partial pressure and indicated intrinsic semiconductor behavior. The mobility of holes, determined by measuring conductivity at fixed compositions (i.e., fixed in Cr_2-O₃), increased with temperature. This behavior can be attributed to hopping-type conduction. For 10^–5, the activation energy for hole hopping was 0.248 eV, and the calculated hole mobilities were 5.4x10^–2 and 2.4x10^–1 V/cm² · s at 500 and 1000°C, respectively. The oxidation kinetics of Cr were determined by measuring the electrical conductivity and electromotive force across the oxide layer at 875°C. The result agreed well with the oxidation data obtained in thermogravimetric tests.     

Oxidation-sulfidation behavior of iron-chromium-nickel alloys

Oxidation-sulfidation studies of Fe-Cr-8Ni alloys with 4, 12, and 22 wt. % Cr were conducted at 750 and 875°C in multicomponent gas mixtures that contained CO, CO₂, CH₄, H₂, and H₂S. The reaction processes resulted in parabolic kinetics. A chromium concentration in the range 0–12 wt. % in the alloy had a negligible effect on the parabolic rate constant; however, the rate constant for the alloy with 22 wt. % Cr was significantly lower. For a given sulfur partial pressure, the oxygen partial pressures required for the formation of a continuous oxide layer in an Fe-22Cr-8Ni alloy were 10² to 10³ times those calculated for Cr-Cr₂O₃ equilibrium at temperatures of 875 and 750° C, respectively.Work supported by the U.S. Energy Research and Development Administration.On visiting appointment from the Academy of Mining and Metallurgy, Cracow, Poland through a fellowship of the International Atomic Energy Agency.     

Preservation, development, and hatching of resting eggs in the freshwater rotifer Brachionus calyciflorus pallas

The resting eggs of Brachionus calyciflorus produced under laboratory by manipulating various environmental conditions were subjected to preservation for long-term storage. Preservation strategies included as storing freshly collected resting eggs, dry resting eggs, and storing at 4°C. Results showed that the resting eggs preserved by drying as they were able to maintain the viability without much variation in the hatchability. The scanning electron micrographs clearly depicted the surface damage as well as change in the shape and surface topography due to the storage. The resting eggs thus stored were traced for their normal embryonic development, during which as many as 11 stages were traced and time taken for each stage of development was observed. Microscopic observations revealed that the first four stages represented the development of embryo and thereafter around 16-18 h extrution of neonate from egg occurred. At 18-19 h of development the characteristic of anterior and posterior spines appeared in the neonate. Just released neonate, after 4-5 h of development reached adult stage. Overall the hatching and embryonic development of the resting eggs preserved by "drying" were normal and hence this method could be adopted for long-term storage.     

Extracting Sentiments by Using Fine-Grained Mining

Wireless Personal Communications - With the rapid development of web, a huge number of reviews about various kinds of products are springing on the Internet. Many users purchase the products...     

Performance of an iron aluminide metal filter in a reducing environment

A laboratory-scale apparatus has been used for unattended, long duration, continuous, flow-through testing of an iron aluminide sintered metal filter under reducing conditions. Two candle specimens were exposed for 1009 to 2251 h to 600 °C gas containing 5% CO, 11% H₂, 12% CO₂, 12% H₂O, 60% N₂, 0.5% H₂S, 2.4 ppmv NaCl, 4.7 ppmv KCl, 26.1 ppmv HCl, and 5530 ppmw ash from a transport reactor operated in gasification mode. A database was established on pressure drop of the as-received and exposed filter as a function of face velocity and temperature. Tests were conducted to investigate the effects of back pulse parameters on filter regenerability. Results are reported on the critical reservoir pressure and pulse duration for maintaining a stable saw-tooth profile of pressure drop across the filter element. Data are obtained to characterize the effect of chemical and thermal aging on tensile strength, fast fracture strength, and microstructure.