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11.
Surfaces with antibacterial and antistatic functionalities are one of the new demands of todays' industry. Therefore, a facile method for the preparation of multifunctional polyaniline/copper/TiO2 (PANI/Cu/TiO2) ternary nanocomposite based on in situ polymerization is presented. This nanocomposite was characterized through the different techniques and was utilized for induction of antibacterial and antistatic properties in polyurethane coatings. Measurement of the conductivity of PANI/Cu/TiO2 ternary nanocomposite indicated higher electrical conductivity of this nanocomposite compared to pure PANI. The antibacterial activity of the modified polyurethane coatings was tested against Gram-positive and Gram-negative bacteria which led to remarkable reduction in bacterial growth. Besides, it was observed that polyurethane coating with 2 wt % content of ternary nanocomposite has a surface electrical resistance equal 4 × 108 Ω/sq which acquires surface electrical resistance of standard antistatic coatings. The final coatings were also characterized in terms of thermal and mechanical properties to investigate the effect of the ternary nanocomposite on improvement of these properties. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48825. 相似文献
12.
Alireza TABARSA Nima LATIFI Abdolreza OSOULI Younes BAGHERI 《Frontiers of Structural and Civil Engineering》2021,15(2):520-536
This study aims to improve the unconfined compressive strength of soils using additives as well as by predicting the strength behavior of stabilized soils using two artificial-intelligence-based models. The soils used in this study are stabilized using various combinations of cement, lime, and rice husk ash. To predict the results of unconfined compressive strength tests conducted on soils, a comprehensive laboratory dataset comprising 137 soil specimens treated with different combinations of cement, lime, and rice husk ash is used. Two artificial-intelligence-based models including artificial neural networks and support vector machines are used comparatively to predict the strength characteristics of soils treated with cement, lime, and rice husk ash under different conditions. The suggested models predicted the unconfined compressive strength of soils accurately and can be introduced as reliable predictive models in geotechnical engineering. This study demonstrates the better performance of support vector machines in predicting the strength of the investigated soils compared with artificial neural networks. The type of kernel function used in support vector machine models contributed positively to the performance of the proposed models. Moreover, based on sensitivity analysis results, it is discovered that cement and lime contents impose more prominent effects on the unconfined compressive strength values of the investigated soils compared with the other parameters. 相似文献
13.
Maryam Samimifar Ali Massumi Abdolreza S. Moghadam 《The Structural Design of Tall and Special Buildings》2020,29(9)
To overcome complexities and shortcomings of previous studies, a new method is proposed to derive an equivalent linear model for predicting seismic hysteretic energy demand of bilinear single degree of freedom (SDOF) models. A new displacement spectrum is defined, which represents hysteretic energy. It is found that by increasing initial period and damping of a nonlinear system in the correct proportion and defining a linear model with these characteristics, the new developed displacement can be achieved. Error minimization is applied through an algorithm to find the optimum equivalent period corresponding to an equivalent damping utilizing two sets of far‐field and near‐field earthquakes. To analyze the effects of stiffness degradation, the proposed algorithm has been implemented on modified Clough hysteretic model as well. Comparing the results, effects of stiffness degradation on the ratio of equivalent to initial period is evident in the short period range, while with increasing initial period, the effect can almost be neglected at higher values of ductility. Nonlinear regression analysis is carried out to provide the equations for predicting equivalent linear parameters as a function of ductility. Despite the previous predictive equations, the proposed model is independent of earthquake characteristics and response‐related parameters, which has increased efficiency as well as simplicity. 相似文献
14.
Mohammad Rezanejad Abdolreza Sheikholeslami Jafar Adabi Mohammadreza Valinejad 《International Journal of Electronics》2016,103(5):868-877
This article proposes a new structure of voltage multiplier for portable pulsed power applications. In this configuration, which is based on capacitor-diode voltage multiplier, the capacitors are charged by low AC input voltage and discharge through the load in series during pulse generation mode. The proposed topology is achieved by integrating of solid-state switches with conventional voltage multiplier, which can increase the low input voltage step by step and generate high-voltage high-frequency pulsed power across the load. After some discussion, simulations and experimental results are provided to verify the effectiveness of the proposed topology. 相似文献
15.
Applied high-frequency(HF)switching devicescan cause electromagnetic interferences(EMI)in pow-er electronic converter.It is necessary for an electro-magnetic compatibility(EMC)design to prospect andconsider its possible EMI levels.AC motor drive systems i… 相似文献
16.
Javad Ahmadi Ali Khaki-Sedigh Abdolreza Ohadi 《International journal of control》2013,86(9):1380-1400
In this article, a new methodology for robust actuator weighting in the control allocation (CA) problem of input redundant feedback systems is addressed. The methodology is based on the control structural properties of the plant which were previously used for control configuration selection. Robust performance (RP) measures including H ∞ norm and structured singular value of the closed-loop system are used in this article. The capability of the approach is proven with application to lateral dynamics control of the vehicle over-actuated with front and rear steering systems. Employing the RP measures, it is concluded that the vehicle feedback control with front steering angles gives superior RP properties in comparison with the feedback loop of the rear steering angles. Based on these results, the penalty weightings in the cost function of the CA unit are determined. Simulation results based on nonlinear seven degrees of freedom vehicle handling model show that the selection of penalty weightings in the CA unit based on the RP properties of the control inputs (front and rear steering angles) improves the RP of the closed-loop. 相似文献
17.
George E. Klinzing Abdolreza Zaltash Craig A. Myler 《Particulate Science and Technology》1987,5(1):95-104
Two new probes for measuring particle velocity and flowrate based on the elctrostatic field nature of a pneumatic transport system are Introduced. The first probe is based on the current of charged particles inducing a current in a coil placed perpendicular to the flow. The magnitude of the current induced appears to be related to the amount of charged particles passing through the coil and the velocity of the particles. The second probe utilizes fluctuations in the electrostatic field which are picked up by two probes placed a fixed distance along the axis of the flow. The signals from these two probes are identical in waveform but of set in time; therefore, the particle velocity can be obtained by cross-correlation techniques. Both probes are non-intrusive and realtively inexpensive. 相似文献
18.
The seismic motion response of a cantilever retaining wall with cohesive and cohesionless backfill materials was evaluated using fully dynamic analysis based on finite difference method. The dynamic analysis was validated based on experimental test results and then compared to analytical and empirical correlations based on Newmark sliding block method. Seven different earthquake events and the backfills with low to high levels of cohesion were considered. Nonlinear regression analyses were carried out to provide correlations between free-field peak ground acceleration (PGA) and maximum relative displacement of the retaining wall. These results were compared to results from empirical and analytical methods. Furthermore, fragility analyses were conducted to determine the probability of damage to the retaining wall for different free-field PGAs and backfill cohesions. It is demonstrated to what extent a small amount of cohesion in backfill material can influence displacement of the retaining wall and probability of damage in seismic conditions. 相似文献
19.
H. Aghajani Derazkola Abdolreza Simchi 《Science & Technology of Welding & Joining》2018,23(3):209-218
In the present work, the feasibility of friction stir welding (FSW) of poly(methyl methacrylate) sheets was studied experimentally and theoretically by employing thermomechanical simulations. The effect of processing parameters including tool plunge depth, tilt angle, tool rotational speed (w), and transverse velocity (v) was investigated to determine suitable conditions to attain sound and defect-free joints. It is shown that a low tool plunge depth of 0.2?mm and a tilt angle of 2° provide suitable material flow to gain sound joints. By controlling the heat input into stir zone by increasing the tool rotational speed and decreasing linear velocity, the formation of defects can be minimised. Mechanical examinations in both longitudinal (LS) and transverse (TS) directions indicate that the highest joint strength of 57?MPa (for LS) and 42?MPa (for TS) are obtained at processing conditions of w?=?25?mm?min?1 and v?=?1600?rev?min?1. The measured tensile strengths are 81 and 60% of the base polymer, respectively. 相似文献
20.
Distributed hydrological models should pass through a careful calibration procedure backed by sensitivity, uncertainty and
predictive analysis before they are utilized as a decision making aid in watershed management and scenario studies. This paper
examines whether the uncertainty of the parameters of the spatially distributed hydrologic model WetSpa causes significant
uncertainty in the model predictions. The WetSpa model is applied to the Torysa river basin, a rather large catchment located
in Slovakia. Parameter estimation, sensitivity and predictive analysis of the model parameters are performed using a model-independent
parameter estimator, PEST. It is found that the correction factor for measured evaporation data has the highest relative sensitivity.
Parameter uncertainty and predictive analysis give an insight of a proper parameter set and parameter uncertainty intervals
and prove that the parameter uncertainty of the model does not result in a significant level of predictive uncertainty. 相似文献