This paper concentrates on the impacts of distributed generation (DG) placement on the radial distribution system. Distributed generation is a term that refers to the generation of energy close to the point of consumption, in order to improve the performance of the electricity grid. It is a well proven fact that if the DGs units are placed in the right place in the distribution system and operating at optimal size, it will help in reducing the line losses and improving the voltage profile and as a consequence the reliability, stability and efficiency of the electrical system are preserved. In this paper, three types of DG units are considered and both Moth-flame optimization (MFO) and Grasshopper optimization (GOA) are applied to find the optimal DG sizing for a typical radial distribution system (IEEE-85 bus radial distribution test systems). The required location of the DG unit bus is selected using the index vector method (IVM) and the voltage stability index (VSI). The obtained results show that the two algorithms produce very same values. The best result in loss reduction and minimum bus voltage is attained for the DG unit at a power factor of 0.93 when compared to other DG types. However, this requires a large DG versus the other types.

In this study, workability and mechanical properties of fluid High-performance concrete containing metal fibers have been investigated experimentally and numerically. A total of 13 mixtures investigated using a response surface (RSM) method. The input variables in the mixtures are the superplasticizer (SP) and metal fibers (MF) percentages. The percentage in SP takes as extreme levels 1.80% and 2.4%. The metal fibers quantity in the concrete ranging from 23 kg/m3 to 37 kg/m3. The slump flow was used to evaluate the rheological properties of mixture at fresh state. For the mechanical characterization, compressive and flexural strength tests were used in the hardened state. The obtained results show that the metal fibers reduce the workability of HPFC mixtures and improve their mechanical properties, especially the ductility. The slump flow (spreading) diameter of all mixtures varied between 400 mm and 580 mm, indicating a good deformability and mobility. Compressive and flexural strength ranged from 82 to 97 MPa and 4.5 to 7.53 MPa, respectively. The ductility was conferred on the HPFRFC composites, while the brittle failure is replaced by a ductile failure. Moreover, the numerical results show that HPFRFC can be produced based on optimized application of superplasticizer and metal fiber content. The optimization results indicate that with 30 Kg/m3 fibers and 2.4% superplasticizer, the maximum 28-day compressive and flexural strength are obtained, while meeting EFNARC workability indicators. This study proved that it is possible to suitably produce a dense and workable HPFRFC that are much thinner, slenderer, lighter, more durable and low cost-effective for practical application..

In this work, two surfactants derived from cetyltrimethylammonium bromide (CTAB) were synthesized by telomerization reaction: N-hexadecyl, N-methyl, N-(1,1 dimethyl) ethoxy amin and zinc di- cetyltrimethylammonium. The first one is a surfactant with a linear hydrocarbon chain C16H33, the second one is a nanocomposite with two linear C16H33 chains. The latter was prepared in distilled water as solvent and zinc dioxide at 50°C. The characterization of these two telomeres was obtained by nuclear magnetic resonance (1H NMR) and differential scanning calorimetry (DSC).

This model allows evaluating the speed of streamers as a function of distances covered and the nature of the insulating materials. Indeed, a database was created from a laboratory model, to train different neuronal methods for predicting the evolution of streamers on the polymers surface which presents an interesting tool for estimating the propagation phenomena.