High Frequency Electronically Tunable Floating Memristor Emulators employing VDGA and Grounded Capacitor

This paper introduces novel electronically tunable floating and grounded memristor emulator circuits using voltage differencing gain amplifier and one capacitor. The decremental and incremental memristor emulators have been suggested for both floating as well as grounded type configurations. Decremental to incremental and incremental to decremental configurations of memristor emulators can be easily obtained. The fingerprint of memristor is the pinched hysteresis loops that are maintained for the significant range of frequencies from 5 kHz to 1 MHz. The proposed memristor emulator sustains its range of frequency for both grounded and floating configurations. The simulations have been done in Eldo simulation tool of Mentor Graphics using TSMC 0.18 µm complementary metal-oxide semiconductor (CMOS) technology parameters. The proposed electronically tunable memristor emulators are used to realize analog filters in view of performance verification.

     

Experimental investigation of particle migration in suspension flow through bifurcating microchannels

Experimental measurements of velocity and concentration profiles were carried out to study transport of non‐colloidal suspension in bifurcating micro channels for both diverging and converging flow conditions using a combination of mirco‐particle image velocimetry and particle tracking velocimetry techniques. Migration of particles across the streamline was observed and symmetric velocity and concentration profile in the inlet branch becomes asymmetric in the daughter branches. Further migration of particles toward the center of the channel in the outlet branch make the profiles again symmetric. The evolution of velocity and concentration profiles was observed to be different in the symmetric and asymmetric bifurcation channels. The comparison of the streamlines for the fluid and the particles showed significant deviation near the bifurcation region. This may explain why there is unequal flow and particle partitioning during flow of suspension in asymmetric bifurcating channels as reported in many previous studies. © 2018 American Institute of Chemical Engineers AIChE J, 64: 2293–2307, 2018     

Development,In Vitro and In Vivo Evaluation of pH Responsive β-CD-Comethacrylic Acid-Crosslinked Polymeric Microparticulate System for Solubility Enhancement of Rosuvastatin Calcium

Current research work was conducted for enhancing solubility of rosuvastatin calcium. A highly stable, biocompatible, and nontoxic β-cyclodextrin-g-poly(methacrylic acid) graft polymeric network was developed. Formulations proved entrapment efficacy (%) in between 82.30?±?0.25 and 89.00?±?0.25 and gel fraction between 90.34?±?1.012 and 95.25?±?1.331. Formulation HM2 had shown optimum swelling and drug release, i.e., 85.74% at pH 6.8. The best-fit model was first-order kinetics with anomalous diffusion as release mechanism. Likewise, solubility enhancement, i.e., 9.59-folds was determined at pH 6.8. It was concluded that hydrogel microparticles are the promising tools for improving solubility and bioavailability of hydrophobic drugs.     

Built-up battened columns under lateral cyclic loading

Built-up members with battens designed for typical 2–2.5% of axial load may not behave satisfactorily in the presence of lateral seismic loads. Analytical evaluation of double-channel battened cantilever members designed as per the current practice, and subjected to constant axial compressive load and gradually increasing lateral load showed that the members failed to reach their expected flexural capacity due to lateral instability. The design of members was modified by changing the configuration of battens in the expected plastic-hinge region, i.e., reducing the spacing of battens in end panel by half, and designing battens for a shear demand due to moment capacity of section. The members with battens designed for moment capacity could able to reach the expected flexural strength. Five half-scale test specimens of battened members designed as per the current practice and improved design method were subjected to axial load and gradually increasing cyclic load. The specimens designed as per improved design method showed excellent performance in terms of lateral strength, lateral stiffness, moment rotation characteristics and energy dissipation capacity.     

Low temperature coefficient and low line sensitivity subthreshold curvature-compensated voltage reference

A high-order curvature-compensated subthreshold voltage reference is proposed in this paper. The proposed curvature-compensated voltage reference consists of two supply-independent first-order voltage references and a curvature compensation circuit. The supply-independent first-order voltage reference uses a negative feedback loop which improves the line sensitivity and eliminates the demand of operational amplifier, whereas the curvature compensation circuit provides high-order temperature-compensated output reference voltage. The proposed curvature-compensated voltage reference provides an output reference voltage of 118.54 mV with a temperature coefficient of 21.5 ppm/°C over a wide temperature range of −60°C to 120°C . The power supply rejection ratio and line sensitivity are observed as −68.64 dB (for the frequency range of 1 Hz to 100 Hz) and 0.035%/V (for the supply voltage varies from 0.85 V to 2.5 V), respectively. The values of output noise at the frequencies of 1 kHz and 10 kHz without using any capacitive filter are obtained as 179.13 nV/ √ Hz and 123.87 nV/ √ Hz , respectively.     

New grounded and floating memristor emulators using OTA and CDBA

In this paper, grounded and floating decremental/incremental memristor emulators have been proposed by using an operational transconductance amplifier (OTA), current differencing buffered amplifier (CDBA), and a grounded capacitor. The proposed memristor emulators are simpler in design over most of the realizations of memristor emulators available in the literature. The proposed configurations of grounded and floating decremental memristor emulators can be easily converted into grounded and floating incremental memristor emulators. The pinched hysteresis loops obtained from proposed memristor emulators are maintained up to 1-MHz frequency in both decremental and incremental configurations. Simulation results have been obtained using a Mentor Graphics Eldo simulation tool in 0.18-μm complementary metal-oxide semiconductor (CMOS) technology parameters. Analog filters have also been designed to verify the performance of proposed grounded and floating memristor emulators.     

Evaluation of physiological and biochemical responses of two rice (Oryza sativa L.) cultivars to ambient air pollution using open top chambers at a rural site in India

Air pollutant concentrations are rising in India, causing potential threats to crop production. As air pollutants are known to interfere with physiological processes, this study was conducted to assess the relative responses of physiological and biochemical characteristics of two cultivars of rice (Oryza sativa L. cv. Saurabh 950 and NDR 97) leading to variable yield responses. Twelve hour monitoring of ambient concentrations of SO₂, NO₂ and O₃ in filtered chambers (FCs), non-filtered chambers (NFCs) and open plots (OPs) showed that O₃ was the main pollutant at the experimental site. Ozone concentrations often exceeded 40 ppb during anthesis but not during the vegetative growth period. Photosynthetic rate (Ps), stomatal conductance (g_s) and Fv/Fm ratio, superoxide dismutase (SOD) and peroxidase (POD) activities and photosynthetic pigments, ascorbic acid, total phenolics and protein contents were assessed at different developmental stages and yield of grains were quantified. Lipid peroxidation, SOD and POD activities, ascorbic acid and total phenolics were higher, whereas Ps, g_s, Fv/Fm ratio and contents of protein and photosynthetic pigment were lower in plants of NFCs as compared to FCs. Yield decreased significantly in both cultivars grown in NFCs. NDR 97 showed less reductions in physiological characteristics, photosynthetic pigments and protein, but a greater increase in the antioxidative defense system as compared to Saurabh 950. Yield reduction was higher in NDR 97 than in Saurabh 950. This suggested that NDR 97 utilized more photosynthate in maintaining the metabolic machinery against O₃ stress leading to lower translocation of photosynthate to reproductive parts. The study concluded that under natural field conditions, physiological and biochemical responses of plants varied with pollutant concentrations leading to different translocation strategies in plants, modifying their yield responses. NDR 97, a fast growing and high yielding cultivar was more sensitive than slow growing Saurabh 950.     

LIBS-an efficient approach for the determination of Cr in industrial wastewater

In the present paper, LIB spectra of different water samples having varying concentration of Cr (certified reference material, CRM) have been recorded by using liquid jet (fabricated in our laboratory) configuration. Calibration curves for different atomic lines of Cr are compared and it is found that calibration curve for Cr II (283.5 nm) atomic line is the best in terms of the Limit of detection (LOD) which is found to be 30 ppm. This calibration curve has been used for quantification of Cr in wastewater collected from Cr-electroplating industry where the concentration of Cr is found to be 1500 ppm. Its removal can be planned by biological system, which is in progress.     

Evaluation of equilibrium constants for deprotonation and lactonisation of α-D-isosaccharinic acid

A great deal of disagreement exists in the literature regarding the intrinsic deprotonation and lactonisation constants of α-D-isosaccharinic acid (ISA). Based on a combination of nuclear magnetic resonance and interpretations using the specific ion interaction theory (SIT) of extensive experimental Ca(ISA)₂(cr) solubility data involving α-D-isosaccharinic acid, the reliable value of log₁₀ K° for [HISA(aq) ISA^? + H⁺] is ?3.27 ± 0.01 and for [HISA(aq) ISL(α-D-isosaccharinate-1,4-lactone)(aq) + H₂O] is 0.49 ± 0.09. These data also provide log₁₀ K° of ?3.76 ± 0.09 for the reaction [ISL(aq) + H₂O ISA^? + H⁺] and ?3.88 ± 0.09 for the composite reaction [HISA(aq) + ISL(aq) ISA^? + H⁺]. Reinterpretation of extensive Ca(ISA)₂(cr) solubility data using the SIT activity coefficient model provides log₁₀ K° of ?6.40 ± 0.09 for [Ca(ISA)₂(cr) Ca²⁺ + 2(ISA)^?] and of 1.70 ± 0.09 for [Ca²⁺ + ISA^? CaISA⁺] which are consistent with all of the available values.