118 research outputs found

    Semi-decentralized Strategies in Structural Vibration Control

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    In this work, the main ideas involved in the design of overlapping and multi-overlapping controllers via the Inclusion Principle are discussed and illustrated in the context of the Structural Vibration Control of tall buildings under seismic excitation. A detailed theoretical background on the Inclusion Principle and the design of overlapping controllers is provided. Overlapping and multi-overlapping LQR controllers are designed for a simplified five-story building model. Numerical simulations are conducted to asses the performance of the proposed semi-decentralized controllers with positive results

    Evaluation of Inter-Specific Hybrid of P. atlantica and P. vera L. cv. ‘Badami - Riz-e-Zarand’ as Pistachio rootstock to Salinity Stress According to Some Growth Indices and Eco-physiological and Biochemical Parameters

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    In order to evaluate the inter-specific hybrid of P. atlantica Desf. and P. vera L. cv. ‘Badami- Riz-e- Zarand’ to salinity stress, a factorial experiment was conducted based on completely randomized design with 0, 60 and 120 mM of salinity levels of sodium chloride, calcium chloride and magnesium chloride (3:2:1) with four replications on ‘Qazvini’, ‘Badami-Riz-e-Zarand’ and inter-specific of P. atlantica Ч P. vera cv. ‘Badami-Rize-Zarand’ rootstocks of pistachio. The results showed that salinity has increased proline content of leaves. Chlorophyll index, relative water content of leaf, leaf area, shoot and root fresh and dry weight, stem diameter and number of leaves were decreased by increasing salinity. Rootstocks responded differently to salinity, so that the most reduction in chlorophyll index, leaf area and leaf number were observed in ‘Badami-Riz-e-Zarand’ rootstock and the least reduction was observed in the hybrid

    Mathematical modeling, analysis, and control of hybrid dynamical systems

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    EditorialPeng Shi, Hamid Reza Karimi, Rongni Yang, and Xiaojie S

    Effect of the Wild Eggplant Rootstock (Solanum torvum) on the Drought Tolerance of Tomato Based on the Growth Indecies and Physiological Parameters

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    Introduction Drought stress in tomatoes reduces fruit quality and yield, also fall leaves and cause of blossom rot. It has been reported that drought stress reduces cell division and causes the stomata to close, followed by a decrease in the flow of carbon dioxide to the mesophyll cells of the leaf. Several methods have been proposed to overcome the drought stress in tomato plants, which can be mentioned the use of drought tolerance genotypes, genetic engineering to identify drought resistant genes and transfer them to sensitive plants, as well as the use of tolerancet rootstocks. It has reported that type of rootstock can effected on tolerance of tomato plants to drought stress. For this reason, the present study was conducted to investigate the effect of wild eggplant rootstock on the drought tolerance of two tomato cultivars.   Material and Methods In order to find the effect of the wild eggplant rootstock on the tolerance of two tomato cultivars, a factorial experiment was conducted as completely randomized design with two factors. Factors were included irrigation period three levels of 3 (control), 6 and 9-day and grafting combination at 6 levels involved non-grafted Dafnis, non-grafted Isabella, self-grafted Dafnis, self grafting Isabella, Isabella grafted on wild eggplant rootstock (S. torvum), and Dafnis grafted on wild eggplant rootstock. The plants were exposed to drought for 54 days. At the end of experiment growth and physiological parmeters including leaf specific, plant height dry weight of shoot as well as photosynthesis parameters, RWC and plant nutrients were measured. The amount of leaf proline was measured according to Paquin and Lichasur methodusing a spectrophotometer at a wavelength of 515 nm. The phenolic compounds of the leaves were measured at a wavelength of 725 nm using a spectrophotometer (Isfendiyaroglu and Zeker, 2002). Also, the membrane stability index (ion leakage percentage) was measured according to Lutts et al.'s method (Lutts et al., 1996).   Results and Discussion The results showed that with increasing irrigation period decreased the most of vegetative parameters, photosynthesis pigments, and mineral nutrients, so that, the highest value was showed at the 3-day irrigation period and the lowest value was at the 9-day irrigation period. Shoot weight decrese is probably due to morphological changes in plant roots, which is a plant response to drought stress. The results also showed that the interaction of irrigation period and grafted combination on some vegetative and ecophysiological parameters was significant. The lowest dry weight of shoot was observed at 9-day of irrigation period in plants of Dafnis grafted on torvum rootstock., Tthe highest dry weight root volume, leaf potassium and phosphorous concentration were at the 3-day irrigation period in self-grafted Dafnis plants.The results also showed that the amount of phenolic compounds in plants of Isabella grafted on torvum rootstock was the highest in 9 days irrigation period which may be due to the rootstock effect on the synthesis of these compounds in the scion. According to the results, the concentration of leaf magnesium in non-grafted plants increased with the increase of the irrigation cycle from 3 days to 9 days, althougth no significant difference was observed between self-grafted and non-grafted plants. In the 9-day irrigation period, the highest concentration of leaf magnesium was observed to non-grafted Daphnis plants, which was significantly different from other grafting combinations compounds except Daphnis self-grafted plants.   Conclusion The results of the present study showed that drought stress had the greatest effect on dry matter, and the amount of photosynthetic indices and pigments in tomato plants. Based on the results of the present study, it was found that the most of the reduce vegetative and physiological parameters was observed in Daphnis cultivar grafted on the thorum rootstock, were significantly reduced compared to self-grafted or non-grafted plants, which it was due to the dwarfing effects of this rootstock or grafting incompatibility. According to the results of the present study, it can be postulated that in drought stress Isabella cultivars grafted on the wild eggplant rootstock had more growh than other combination grafting. Hence it proposed more studies in this case

    LMI-based design of distributed energy-dissipation systems for vibration control of large multi-story structures

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    In this paper, we present an advanced computational procedure that allows obtaining distributed energy-dissipation systems for large multi-story structures. The proposed methodology is based on a decentralized velocity-feedback energy-to-componentwise-peak (ECWP) controller design approach and can be formulated as a linear matrix inequality (LMI) optimization problem with structure constraints. To demonstrate the effectiveness of the proposed design methodology, a passive damping system is computed for the seismic protection of a 20-story building equipped with a complete set of interstory viscous dampers. The high-performance characteristics of the obtained passive ECWP control system are clearly evidenced by the numerical simulation results. Also, the computational effectiveness of the proposed design procedure is confirmed by the low computation time of the associated LMI optimization problem.Peer ReviewedPostprint (published version

    The effect of substrate clamping on the paraelectric to antiferroelectric phase transition in Nd-doped BiFeO₃ thin films

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    Thin films were deposited on Pt/Ti/SiO₂/Si substrates using pulsed laser deposition from a target with a composition (Bi₀.₈₂₅Nd₀.₁₇₅Fe₀.₉₇Ti₀.₀₃O₃) with 5 mol% excess Bi₂O₃ within the antiferroelectric (AFE) region of the NdFeO₃-BiFeO₃ phase diagram. However, Raman spectroscopy and transmission electron microscopy (TEM) revealed that films consisted of a mosaic microstructure in which (AFE), ferroelectric (FE) and paraelectric (PE) phases coexisted. Variation in the spatial distribution of Nd is typically greater in bulk ceramics than in thin films and therefore, the absence of single phase AFE cannot be attributed to local changes in composition. Instead, it is proposed that clamping due to mismatch in thermal expansion coefficient with the substrate suppresses the large volume change associated with the PE-FE and PE-AFE transition in bulk and its absence in the thin film prevents an avalanche-like transition throughout grains, which in bulk sustains single phase AFE, irrespective of local deviations in the Nd concentration

    Modification of immobilized titanium dioxide nanostructures by argon plasma for photocatalytic removal of organic dyes

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    The aim of this study was to modify surface properties of immobilized rutile TiO 2 using Argon cold plasma treatment and to evaluate the performance of the catalyst in photocatalytic elimination of synthetic dyes in UV/TiO 2 /H 2 O 2 process. The surface-modified TiO 2 was characterized by XRD, EDX, SEM, UV-DRS and XPS analyses. Response surface methodology was adopted to achieve high catalyst efficiency by evaluating the effect of two main independent cold plasma treatment parameters (exposure time and pressure) on surface modification of the catalyst. The increase of the plasma operation pressure led to higher decolorization percentage, while the increase of plasma exposure time decreased the decolorization efficiency. RSM methodology predicted optimum plasma treatment conditions to be 0.78 Torr and 21 min of exposure time, which resulted in decolorization of 10 mg/L solution of the malachite green solution by 94.94 in 30 min. The plasma treatment decreased the oxygen to titanium ratio and caused oxygen vacancy on the surface of the catalyst, resulting in the superior performance of the plasma-treated catalyst. Pseudo first-order kinetic rate constant for the plasma-treated catalyst was 4.28 and 2.03 times higher than the rate constant for the non-treated photocatalyst in decolorization of aqueous solutions of malachite green and crystal violet, respectively. © 2019 by the authors

    Induction and aggravation of atrioventricular valve regurgitation in the course of chronic right ventricular apical pacing

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    Aims Valvular regurgitation, especially on the right side of the heart, is a common finding even in patients without endocardial pacing leads. The severity of valvular regurgitation can change after permanent pacemaker (PPM) implantation. Ventricular pacing has been shown to cause ventricular dysfunction. The purpose of this study was to evaluate the mid-term effects of right ventricular (RV) apical pacing on atrioventricular (AV) valvular regurgitation in patients with a normal left ventricular function before PPM implantation. Methods and results Patients who required dual-chamber pacemakers due to a high-degree AV block were enrolled in the study. Initial echocardiography was performed before PPM implantation and re-evaluation by echocardiography was performed every 24 months thereafter. A total of 125 patients (61 male; mean age: 66.57 ± 6.45 years) were included in the study, and 115 pacemaker-dependent patients were followed up (mean ± SD; 4.08 ± 0.8 years). Echocardiography demonstrated mild tricuspid regurgitation (TR) and mitral regurgitation (MR) in 70 (60.1) and 34 (29.6) patients before PPM implantation, respectively. Moderate TR and MR were detected in 10 (8.7) and 1 (0.9) patients, respectively. Thirty-six (31.6) patients showed moderate-to-severe TR at long-term follow-up, compared with the 10 (8.7) patients, who had the same degree of TR before RV apical pacing (P< 0.001). Mild and moderate MR were detected in 54 (47) and 8 (7) patients after PPM implantation on the last echocardiography(P< 0.001). Baseline systolic pulmonary artery pressure (PAP) was 29.24 ± 8.45 mmHg, which increased to 36 ± 11 mmHg on the last echocardiography (P< 0.001). Conclusion Considering the haemodynamic effects at mid-term follow-up, left ventricular dysfunction is rare in patients with RV apical pacing and normal baseline left ventricular function. Right ventricular apical pacing is associated with a significant increase in the prevalence and severity of TR and MR. © The Author 2011
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