11 research outputs found

    Static anti-windup compensator design for locally Lipschitz systems under input and output delays

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    This paper proposes a static anti-windup compensator (AWC) design methodology for the locally Lipschitz nonlinear systems, containing time-varying interval delays in input and output of the system in the presence of actuator saturation. Static AWC design is proposed for the systems by considering a delay-range-dependent methodology to consider less conservative delay bounds. The approach has been developed by utilizing an improved Lyapunov-Krasovskii functional, locally Lipschitz nonlinearity property, delay-interval, delay derivative upper bound, local sector condition, L2 gain reduction from exogenous input to exogenous output, improved Wirtinger inequality, additive time-varying delays, and convex optimization algorithms to obtain convex conditions for AWC gain calculations. In contrast to the existing results, the present work considers both input and output delays for the AWC design (along with their combined additive effect) and deals with a more generic locally Lipschitz class of nonlinear systems. The effectiveness of the proposed methodology is demonstrated via simulations for a nonlinear DC servo motor system, possessing multiple time-delays, dynamic nonlinearity and actuator constraints

    Actual and Predicted Evapotranspiration Along with Groundwater Contribution for Wheat Crop

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    This experiment aimed to determine the crop evapotranspiration (ETc), groundwater input in total water used by wheat crop, and to simulate the CROPWAT model to envisage the crop evapotranspiration rate. To estimate on-field ETc and groundwater contribution the combining lysimeter technique was used. The water levels below the soil surface were kept at 1.60, 2.20, and 2.80 m and each water table depth was replicated three times. The experiment was conducted under silt loam (SL) and silty-clay loam (SCL) soil conditions. The climatic parameters and water balance components were recorded accordingly. The on-field ETc was compared with the predicted ETc by CROPWAT model. Under SL soil, the observed ETc was 442, 427, and 401 mm at the water table depth of 1.60, 2.20, and 2.80 m, respectively. The recorded ETc under SCL soil was 419, 402, and 389 mm at the same water table depths, respectively. The ETc reduced with an increase in water level below the surface. The groundwater contribution at 1.60, 2.20 and 2.80 m depth of water level under SL and SCL soil was observed as 50, 41, and 30 % and 43, 34, and 24 %, respectively. The predicted ETc by CROPWAT model for SL and SCL soil conditions was 428.8 and 410.7 mm, respectively. The projected ETc is likely equal to the average ETc observed under lysimeter experiment. Thus, the use of CROPWAT model is recommended to overcome waterlogging and salinity problems and to conserve water resources

    Assessing evapotranspiration rate and sesame (Sesamum indicum) crop water use under different water table depths

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    This research was intended to determine the groundwater contribution in crop water-use of sesame crop under different water tables depths and to assess the accuracy of CROPWAT model to simulate the evapotranspiration. The method of combining Lysimeters was implemented to investigate seasonal groundwater contribution to crop-water use. The climatic conditions under which crop was grown were monitored, water table depths were maintained (at 1.60 m, 2.0 m and 2.40 m) and all water balance components were measured. The crop coefficient (Kc), ET and reference evapotranspiration (ETo) were determined. The obtained results were compared with the outputs of the CROPWAT model. The results reveals that, the average ET of sesame crop under lysimeter experiment was about 450 mm which was slightly increased under increased water table depths. Around 40% of groundwater contribution was recorded in overall crop-water use. The crop coefficient values were exceeded above 1.0 due to high foliage, developed through better canopy cover. The average water use efficiency was observed as 21 kg/m3. The predictions of CROPWAT model were virtually same as observed in the lysimeter experiment. The total ET was predicted as 434 mm, the predicted crop coefficient were ranging from 0.38 to 0.98. The soil moisture balance predicted by the model reveals the same trend of soil moisture balance as observed in the field. The predicted irrigation schedule was also resembling the same trend of irrigation applications as observed under lysimeter experiment. Thus, the utilization of CROPWAT model is durably suggested to be used as management tool to overcome the salinity and waterlogging problems caused by over irrigation events

    Enhanced Energy Storage Performance by Relaxor Highly Entropic (Ba0.2Na0.2K0.2La0.2Bi0.2)TiO3 and (Ba0.2Na0.2K0.2Mg0.2Bi0.2)TiO3 Ferroelectric Ceramics

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    Dielectric ceramic capacitors have attained considerable attention due to their energy storage performance in the field of advanced high/pulsed power capacitors. For such a purpose, configurationally disordered composite material engineering, with the substitution of suitable oxide cations at a single lattice site have demonstrated a strong dielectric relaxor phase with the ability to show high performance capacitive properties. Herein, two prominent high-entropy ceramics systems (Ba0.2Na0.2K0.2A0.2Bi0.2)TiO3, (with A = La and Mg) were fabricated to evaluate their structural, ferroelectric and dielectric properties. XRD patterns and Rietveld refinement of the XRD analysis confirmed the cubic structure Pm3¯m space group of the ceramics. The relative dielectric analysis of Ba0.2Na0.2K0.2La0.2Bi0.2TiO3 (BNKLBT) and Ba0.2Na0.2K0.2Mg0.2Bi0.2TiO3 (BNKMBT) ceramics were demonstrated with relaxor ferroelectric behavior having diffusion coefficients of 1.617 and 1.753, respectively. Moreover, BNKLBT and BNLMBT ceramics presented better stored energy density (1.062 J/cm3 and 0.8855 J/cm3, respectively) and high energy conversion efficiency (80.27% and 82.38%, respectively) at an electric field of 100 kV/cm. The results clearly demonstrate that such high-entropy configured ceramics have the potential to be used in efficient energy storage devices

    Enhanced Energy Storage Performance by Relaxor Highly Entropic (Ba<sub>0.2</sub>Na<sub>0.2</sub>K<sub>0.2</sub>La<sub>0.2</sub>Bi<sub>0.2</sub>)TiO<sub>3</sub> and (Ba<sub>0.2</sub>Na<sub>0.2</sub>K<sub>0.2</sub>Mg<sub>0.2</sub>Bi<sub>0.2</sub>)TiO<sub>3</sub> Ferroelectric Ceramics

    No full text
    Dielectric ceramic capacitors have attained considerable attention due to their energy storage performance in the field of advanced high/pulsed power capacitors. For such a purpose, configurationally disordered composite material engineering, with the substitution of suitable oxide cations at a single lattice site have demonstrated a strong dielectric relaxor phase with the ability to show high performance capacitive properties. Herein, two prominent high-entropy ceramics systems (Ba0.2Na0.2K0.2A0.2Bi0.2)TiO3, (with A = La and Mg) were fabricated to evaluate their structural, ferroelectric and dielectric properties. XRD patterns and Rietveld refinement of the XRD analysis confirmed the cubic structure Pm3¯m space group of the ceramics. The relative dielectric analysis of Ba0.2Na0.2K0.2La0.2Bi0.2TiO3 (BNKLBT) and Ba0.2Na0.2K0.2Mg0.2Bi0.2TiO3 (BNKMBT) ceramics were demonstrated with relaxor ferroelectric behavior having diffusion coefficients of 1.617 and 1.753, respectively. Moreover, BNKLBT and BNLMBT ceramics presented better stored energy density (1.062 J/cm3 and 0.8855 J/cm3, respectively) and high energy conversion efficiency (80.27% and 82.38%, respectively) at an electric field of 100 kV/cm. The results clearly demonstrate that such high-entropy configured ceramics have the potential to be used in efficient energy storage devices

    Single- and Multilayered Perovskite Thin Films for Photovoltaic Applications

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    Organic&ndash;inorganic lead halide perovskites materials have emerged as an innovative candidate in the development of optoelectronic and photovoltaic devices, due to their appealing electrical and optical properties. Herein, mix halide single-layer (~95 nm) and multilayer (average layer ~87 nm) CH3NH3PbIBr2 thinfilms were grown by a one-step spin coating method. In this study, both films maintained their perovskite structure along with the appearance of a pseudo-cubic phase of (200) at 30.16&deg;. Single-layer and multilayer CH3NH3PbIBr2 thinfilms displayed leaky ferroelectric behavior, and multilayered thinfilm showed a leakage current of ~5.06 &times; 10&minus;6 A and resistivity of ~1.60 &times; 106 &Omega;.cm for the applied electric field of 50 kV/cm. However, optical analysis revealed that the absorption peak of multilayered perovskite is sharper than a single layer in the visible region rather than infrared (IR) and near-infrared region (NIR). The band gap of the thinfilms was measured by Tauc plot, giving the values of 2.07 eV and 1.81 eV for single-layer and multilayer thinfilms, respectively. The structural analysis has also been performed by Fourier transform infrared spectroscopy (FTIR). Moreover, the fabricated CH3NH3PbIBr2 as an absorber layer for photoelectric cell demonstrated a power conversion efficiency of 7.87% and fill factor of 72%. Reported electrical, optical and photoelectric efficiency-based results suggest that engineered samples are suitable candidates for utilization in optoelectronic and photovoltaic devices

    Genetic insights into biological mechanisms governing human ovarian ageing

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    Reproductive longevity is essential for fertility and influences healthy ageing in women1,2, but insights into its underlying biological mechanisms and treatments to preserve it are limited. Here we identify 290 genetic determinants of ovarian ageing, assessed using normal variation in age at natural menopause (ANM) in about 200,000 women of European ancestry. These common alleles were associated with clinical extremes of ANM; women in the top 1% of genetic susceptibility have an equivalent risk of premature ovarian insufficiency to those carrying monogenic FMR1 premutations3. The identified loci implicate a broad range of DNA damage response (DDR) processes and include loss-of-function variants in key DDR-associated genes. Integration with experimental models demonstrates that these DDR processes act across the life-course to shape the ovarian reserve and its rate of depletion. Furthermore, we demonstrate that experimental manipulation of DDR pathways highlighted by human genetics increases fertility and extends reproductive life in mice. Causal inference analyses using the identified genetic variants indicate that extending reproductive life in women improves bone health and reduces risk of type 2 diabetes, but increases the risk of hormone-sensitive cancers. These findings provide insight into the mechanisms that govern ovarian ageing, when they act, and how they might be targeted by therapeutic approaches to extend fertility and prevent disease

    Genetic insights into biological mechanisms governing human ovarian ageing.

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    Reproductive longevity is essential for fertility and influences healthy ageing in women &lt;sup&gt;1,2&lt;/sup&gt; , but insights into its underlying biological mechanisms and treatments to preserve it are limited. Here we identify 290 genetic determinants of ovarian ageing, assessed using normal variation in age at natural menopause (ANM) in about 200,000 women of European ancestry. These common alleles were associated with clinical extremes of ANM; women in the top 1% of genetic susceptibility have an equivalent risk of premature ovarian insufficiency to those carrying monogenic FMR1 premutations &lt;sup&gt;3&lt;/sup&gt; . The identified loci implicate a broad range of DNA damage response (DDR) processes and include loss-of-function variants in key DDR-associated genes. Integration with experimental models demonstrates that these DDR processes act across the life-course to shape the ovarian reserve and its rate of depletion. Furthermore, we demonstrate that experimental manipulation of DDR pathways highlighted by human genetics increases fertility and extends reproductive life in mice. Causal inference analyses using the identified genetic variants indicate that extending reproductive life in women improves bone health and reduces risk of type 2 diabetes, but increases the risk of hormone-sensitive cancers. These findings provide insight into the mechanisms that govern ovarian ageing, when they act, and how they might be targeted by therapeutic approaches to extend fertility and prevent disease
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