Modified method for transformer magnetizing characteristic computation and point-on-wave control switching for inrush current mitigation

This paper proposes a new model for the low-frequency transient analysis of a transformer, with a modified equation for calculation of the flux-current characteristic representing the saturation inductance of the transformer. The model is based on the V-I (voltage-current) no-load curves and uses the no-load reactive power losses. To validate the model, it was used to simulate the no-load magnetizing current in steady-state condition, as well as the transient inrush current at network frequency. Evaluation was done both by comparing the simulation results obtained with the proposed model and those available in the relevant literature, and by practical measurements. The experimental results presented in this paper were obtained via a laboratory setup and a data acquisition system based on the dSPACE board 1104. Moreover, a control switching to mitigate the transient inrush current in a transformer was developed and applied experimentally in the laboratory and also in the simulations. This control strategy was performed by taking into account the residual flux at the opening instant of the related circuit breaker. A comparative study was carried out showing the validity of the proposed model and the mitigation technique.     

Comparative Study of Fatty Acid Composition,Total Phenolics,and Antioxidant Capacity in Rapeseed Mutant Lines

There is limited variability within rapeseed germplasm in Morocco. Induced mutation was recently used to generate novel genetic variability and develop mutant lines combining desirable traits. In this context, nine promising advanced rapeseed M₂ mutant lines and the wild-type variety “INRA-CZH2” were evaluated for their seed oil content, fatty acid composition, total phenolic content (TPC), and free-radical scavenging activity (FRSA) by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) methods. The results showed significant variability among all mutants in seed oil content (38.14–42.04%) and fatty acids (SAFA = 5.49–10.99%, MUFA = 50.33–71.62%, PUFA = 22.89–8.68%). The mutant H2M-5 exhibited the highest fraction of MUFA and the lowest proportion of SAFA and PUFA, while the mutant H2M-4 showed the highest SAFA and PUFA amounts and the lowest MUFA level. TPC varied from 2.16 to 4.35 mg GAE/100 g. The highest amount was found in the mutant H2M-1, which is about twice that of other mutants and the wild-type variety. FRSA differed significantly among the samples, and the variations observed for DPPH and ABTS methods were 40.5–59.28% and 40.31–59.86%, respectively. FRSA was positively correlated to TPC in the sampled oils (r = 0.801 and 0.802, P < 0.01). This is the first report emphasizing the biochemical potential of rapeseed varieties and novel mutants in Morocco. H2M-1, H2M-4, and H2M-5 were proposed for the Rapeseed National Breeding Program, as they showed higher levels in some biochemical traits of interest.     

Zinc-Blende MnTe Under Pressure: Structural,Mechanical, and Optical Properties from Ab Initio Calculation

We present first-principles studies of structural, mechanical, and optical properties of zinc blende MnTe using the pseudopotential plane-wave method within the local density approximation. The effect of hydrostatic pressure on investigated properties has been examined and discussed. At zero pressure, our results are found to agree reasonably well with those reported in the literature. The generalized elastic stability criteria showed that the material of interest is mechanically stable in all the studied pressure ranges. Applied pressure is found to shift all optical spectra under consideration, giving new optical parameters.     

Electrochemical polymerization and in situ FTIRS study of conducting polymers obtained from o-aminobenzoic with aniline at platinum electrodes

The electrochemical copolymerization of o-aminobenzoic acid with aniline (ANI) was carried out on platinum electrodes in perchloric acid aqueous medium by cyclic scanning of the potential. Electrochemical homopolymerization of o-aminobenzoic acid was also done. Experimental results showed that the polymers are formed in all cases and the presence of aniline promoted markedly the growth of the rate of copolymerization.The obtained polymer films have been characterized by cyclic voltammetry and in situ Fourier transform infrared (FTIR) spectroscopy. The mechanism of the electrochemical polymerization reaction has been discussed.     

钢-混凝土粘结预测的人工神经网络模型

提出人工神经网络模型来模拟传统的带肋钢筋和混凝土之间的粘结性能,目的是预测钢筋从混凝土混合物中拔出的极限荷载(第一神经网络模型)或抗压强度(第二神经网络)以及根据RILEM试验设计的不同钢筋直径的拔出极限荷载。采用112个带肋钢筋(直径为10mm、12mm)以及三种不同混凝土配合比的拔出试验结果数据库,对神经网络模型进行训练。根据反向传播算法,进行多层感知器训练。第一个模型(ANN-6)有6个输入:钢筋直径、水灰比、砂石比、级配、水泥种类和混凝土龄期。第二个模型(ANN-2)有2个输入:钢筋直径、混凝土抗压强度,两个模型的输出均为极限拔出荷载。研究结果显示:所采用的模型预测精度高、误差低、具有鲁棒性。从鲁棒性方面,第一个模型(ANN-6)比第二个模型(ANN-2)更精确。将混凝土的成分作为输入参数,而不是混凝土的强度,对于带肋钢筋-混凝土界面的局部现象更具代表性。     

Nitrogen-vacancy-assisted magnetometry of paramagnetic centers in an individual diamond nanocrystal

Semiconductor nanoparticles host a number of paramagnetic point defects and impurities, many of them adjacent to the surface, whose response to external stimuli could help probe the complex dynamics of the particle and its local, nanoscale environment. Here, we use optically detected magnetic resonance in a nitrogen-vacancy (NV) center within an individual diamond nanocrystal to investigate the composition and spin dynamics of the particle-hosted spin bath. For the present sample, a ～45 nm diamond crystal, NV-assisted dark-spin spectroscopy reveals the presence of nitrogen donors and a second, yet-unidentified class of paramagnetic centers. Both groups share a common spin lifetime considerably shorter than that observed for the NV spin, suggesting some form of spatial clustering, possibly on the nanoparticle surface. Using double spin resonance and dynamical decoupling, we also demonstrate control of the combined NV center-spin bath dynamics and attain NV coherence lifetimes comparable to those reported for bulk, Type Ib samples. Extensions based on the experiments presented herein hold promise for applications in nanoscale magnetic sensing, biomedical labeling, and imaging.     

Efficient traces’ collection mechanisms for passive testing of Web Services

Web Services are a novel approach for business-to-business interactions. Their management, especially fault and performance management, is becoming necessary for their success and emergence. Nowadays, this management is platform-dependent and does not allow third parties to be involved. In this paper, we consider management of Web Services by passive testing where the tester itself is a Web Service. We propose different architectures for observation of simple and composite Web Services. We also study a set of online traces collection mechanisms and discuss their performances in terms of required CPU/RAM resources and introduced network overhead. These performances are then maximized by selecting best locations of observers. Observation considers both functional and non-functional (QoS) properties of Web Services. The paper presents also our experiments using different observation architectures and traces collection mechanisms while observing a simple and a composite Web Service.