46 research outputs found

    Human resource: what contribution to flexibility? Case study: A Group of Algerian Company

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    Evaluation is pervasive and it is necessary for everyone to know its need because it has a big impact on the company accordingly it highlights the needs and the decisions taken of the organization. In the current context where the environment is characterized by complexity and uncertainty, companies must adapt and respond quickly to change. Human capital is considered as a resource for the organization, the most important without any doubt. The role of HR is to encourage initiatives to develop the potential sources of flexibility. Thus the assessment remains essential and necessary at the time of the transition of the Algerian economy to a market economy. Our problem is as follows: the human resource is a brake or business flexibility factor? Our study attempts to explore and apply the research tool of Volberd practiced by a group of companies, such as two-dimensional concept of flexibility in order to characterize their flexibility profiles and highlight the contribution of human resources, as a variable flexibility

    Selective Synthesis, Characterization and Kinetics Studies of poly(α-Methyl styrene) induced by Maghnite-Na+ Clay (Algerian MMT)

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    A new and efficient catalyst of Na-Montmorillonite (Na+-MMT) was employed in this paper for α-methylstyrene (AMS) cationic polymerization. Maghnite clay, obtained from Tlemcen Algeria, was investigated to remove heavy metal ion from wastewater. “Maghnite-Na” is a Montmorillonite sheet silicate clay, exchanged with sodium as an efficient catalyst for cationic polymerization of many vinylic and heterocyclic monomers. The various techniques, including 1H-NMR, 13C-NMR, IR, DSC and Ubbelohde viscometer, were used to elucidate structural characteristics and thermal properties of the resulting polymers. The structure compositions of “MMT”, “H+-MMT” and “Na+-MMT” have been developed. It was found that the cationic polymerization of AMS is initiated by Na+-MMT at 0 °C in bulk and in solution. The influences of reaction temperature, solvent, weight ratio of initiator/monomer and reaction time on the yield of monomer and the molecular weight are investigated. The kinetics indicated that the polymerization rate is first order with respect to the monomer concentration. A possible mechanism of this cationic polymerization is discussed based on the results of the 1H-NMR Spectroscopic analysis of these model reactions. A cationic mechanism for the reaction was proposed. From the mechanism studies, it was showed that monomer was inserted into the growing chains

    Methyl Methacrylate and Alpha-Methyl Styrene: New Strategy for Synthesis of Bloc Copolymers for Use in Potential Biomedical Applications Generated by an Ecologic Catalyst Called Maghnite (Algerian MMT)

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    A new model for synthesis of the plastics, block copolymers were prepared from methyl methacrylate (MMA) and alpha-methyl styrene (α-MS) by cationic copolymerization in the presence of a new and efficient catalyst of “Maghnite-Na” at 0 °C in bulk. In this paper, the copolymerization of α-MS and MMA was induced in heterogeneous phase catalyzed by Maghnite-Na was investigated under suitable conditions. The “Maghnite-Na” is a montmorillonite sheet silicate clay, with exchanged sodium cations to produce Na-Montmorillonite (Na+-MMT) obtained from Tlemcen, Algeria, was investigated to remove heavy metal ion from wastewater as an efficient catalyst for cationic polymerization of many vinylic and heterocyclic monomers. The synthesized copolymer were characterized by Nuclear Magnetic Resonance (NMR-1H, NMR-13C), FT-IR spectroscopy, Differential Scanning Calorimetry (DSC), and Gel Permeation Chromatography (GPC) to elucidate structural characteristics and thermal properties of the resulting copolymers. The structure compositions of “MMT”, “H+-MMT” and “Na+-MMT” have been developed. The effect of the MMA/α-MS molar ratio on the rate of copolymerization, the amount of catalyst, temperature and time of copolymerization on yield of copolymers was studied. The yield of copolymerization depends on the amount of Na+-MMT used and the reaction time. The kinetic studies indicated that the polymerization rate is first order with respect to monomer concentration. A possible mechanism of this cationic polymerization is discussed based on the results of the 1H-NMR Spectroscopic analysis of these model reactions. A cationic mechanism for the reaction studies showed that monomer was inserted into the growing chains.

    OPTIMAL LOCATION AND SIZING OF MULTIPLE DISTRIBUTED GENERATORS IN RADIAL DISTRIBUTION NETWORK USING METAHEURISTIC OPTIMIZATION ALGORITHMS

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    . The satisfaction of electricity customers and environmental constraints imposed have made the trend towards renewable energies more essential given its advantages such as reducing power losses and enhancing voltage profiles. This study addresses the optimal sizing and setting of Photovoltaic Distributed Generator (PVDG) connected to Radial Distribution Network (RDN) using various novel optimization algorithms. These algorithms are implemented to minimize the Multi-Objective Function (MOF), which devoted to optimize the Total Active Power Loss (TAPL), the Total Voltage Deviation (TVD), and the overcurrent protection relays (OCRs)’s Total Operation Time (TOT). The effectiveness of the proposed algorithms is validated on the test system standard IEEE 33-bus RDN. In this paper is presented a recent meta-heuristic optimization algorithm of the Slime Mould Algorithm (SMA), where the results reveal its effectiveness and robustness among all the applied optimization algorithms, in identifying the optimal allocation (locate and size) of the PVDG units into RDN for mitigating the power losses, enhance the RDN system's voltage profiles and improve the overcurrent protection system. Accordingly, the SMA approach can be a very favorable algorithm to cope with the optimal PVDG allocation problem

    Optimal design of wind energy generation in electricity distribution network based on technical-economic parameters

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    In order to satisfy electricity customers and avoid some environmental constraints and problems, the transition to renewable energy sources has become increasingly important given their advantages and benefits, such as reducing pollution and improving the reliability of the targeted distribution system. In this paper, several state-of-the-art metaheuristic optimisation algorithms are used to investigate the optimal setting and sizing of wind turbines (WTs) when connected to the electricity distribution network (EDN). The selected algorithms were implemented to optimise and minimise a multi-objective function (MOF) considered as the sum of the techno-economic parameters of total active power loss (TAPL), total voltage deviation (TVD) and investment cost of the WTG (ICWTG) when the daily uncertainties and variations of the load-source powers are taken into account. The effectiveness of the selected algorithms was validated on the two standard test systems IEEE 33-bus and 69-bus. The simulation results in this paper showed the superiority of the Gorilla Troops Optimizer (GTO) algorithm compared to other new metaheuristic optimisation algorithms in terms of providing the best optimised results. Accordingly, the GTO algorithm showed excellent effectiveness and robustness in determining the optimal setting and sizing of the WTG units in EDN. Thus, the daily active power losses were reduced to 1,415 MWh for the first test system and 1,072 MWh for the second test system, while also improving the bus voltage profiles and favouring the investment costs of the installed WTG units, all with daily uncertainties in terms of load demand and WTG power variations

    Synthesis of Poly(N-vinyl-2-pyrrolidone-co-methyl methacrylate) by Maghnite-H+ a Non-toxic Catalyst

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    In the present work poly (N-vinyl-2-pyrrolidone-co-methyl methacrylate) copolymers were prepared successfully and cleanly by a one step process via cationic copolymerization of N-vinyl-2-pyrrolidone (NVP) with methyl methacrylate (MMA), in heterogeneous phase using “Maghnite-H+” (Mag-H+) as catalyst in bulk, Maghnite is a montmorillonite sheet silicate clay exchanged with protons to produce Maghnite-H+. Temperature is varied between 20 and 80 °C. The effects of reaction temperature, amount of Mag-H+ on the yield and the intrinsic viscosity (η) were investigated. A typical reaction product of poly (NVP-co- MMA) was analyzed by infra red spectroscopy (FTIR) and 1H-NMR, 13C-NMR spectroscopy as well as by viscosimetry. © 2014 BCREC UNDIP. All rights reservedReceived: 24th November 2013; Revised: 30th June 2014; Accepted: 8th July 2014How to Cite: Benadda, M., Ferrahi, M.I., Belbachir, M. (2014). Synthesis of Poly(N-vinyl-2-pyrrolidone-co-methyl methacrylate) by Maghnite-H+ a Non-toxic Catalyst. Bulletin of Chemical Reaction Engineering &amp; Catalysis, 9 (3): 201-206. (doi: 10.9767/bcrec.9.3.5743.201-206)Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.3.5743.201-206</p

    A Brief Review on Mathematical Tools Applicable to Quantum Computing for Modelling and Optimization Problems in Engineering

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    Since its emergence, quantum computing has enabled a wide spectrum of new possibilities and advantages, including its efficiency in accelerating computational processes exponentially. This has directed much research towards completely novel ways of solving a wide variety of engineering problems, especially through describing quantum versions of many mathematical tools such as Fourier and Laplace transforms, differential equations, systems of linear equations, and optimization techniques, among others. Exploration and development in this direction will revolutionize the world of engineering. In this manuscript, we review the state of the art of these emerging techniques from the perspective of quantum computer development and performance optimization, with a focus on the most common mathematical tools that support engineering applications. This review focuses on the application of these mathematical tools to quantum computer development and performance improvement/optimization. It also identifies the challenges and limitations related to the exploitation of quantum computing and outlines the main opportunities for future contributions. This review aims at offering a valuable reference for researchers in fields of engineering that are likely to turn to quantum computing for solutions. Doi: 10.28991/ESJ-2023-07-01-020 Full Text: PD

    A New Design of a Wideband Miniature Antenna Array

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    In this work, we present a new configuration of a new miniature microstrip antenna array having a wide frequency band and with a circular polarization. The bandwidth is about 2GHz for a reflection coefficient under -10dB and centered on the ISM ‘Industrial Scientific Medical’ band at 5.8 GHz. To design such array, we have started the design by validating one antenna element at 10 GHz and after that by using the technique of defected ground, we have validated the antenna array in the frequency band [4 GHz -6 GHz] which will permit to miniature the dimensions. The final fabricated antenna array is mounted on an FR4 substrate, the whole area is 102.48 X 31.39 mm2  with a gain of 5dBi at 4GHz
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