Permanent and Dynamic Behaviours of Self-excited Induction Generator In balanced mode

Due to its various advantages over the synchronous generator, the induction machine (IM) can be used as a generator in remote and rural areas. It be haves as a generator when its rotor is driven above its asynchronous speed. The required reactive power is provided by a local capacitors bank connected to the stator of the IM. Both permanent and transient modes of the self excited induction generator (SEIG) are studied. In both cases (loaded and no-loaded), the evolution of the output voltage for different values of the excitation capacitor and speed is presented. We analyze also, the influence of the capacitors and speed values on start-up of the SEIG. A comparison between laboratory tests and simulation results is done, that demonstrate the effectiveness of the proposed modelDue to its various advantages over the synchronous generator, the induction machine (IM) can be used as a generator in remote and rural areas. It be haves as a generator when its rotor is driven above its asynchronous speed. The required reactive power is provided by a local capacitors bank connected to the stator of the IM. Both permanent and transient modes of the self excited induction generator (SEIG) are studied. In both cases (loaded and no-loaded), the evolution of the output voltage for different values of the excitation capacitor and speed is presented. We analyze also, the influence of the capacitors and speed values on start-up of the SEIG. A comparison between laboratory tests and simulation results is done, that demonstrate the effectiveness of the proposed model

Layered LiNi0.5Co0.5O2 cathode materials grown by soft-chemistry via various solution methods

[Abstract] The lithiated nickel–cobalt oxide LiNi0.5Co0.5O2 used as cathode material was grown at low-temperature using different aqueous solution methods. The wet chemistry involved the mixture of metal salts (acetates or nitrates) with various carboxylic acid-based aqueous solutions. Physicochemical and electrochemical properties of LiNi0.5Co0.5O2 products calcined at 400–600°C were extensively investigated. The four methods used involved complexing agents such as either citric, oxalic, aminoacetic (glycine), or succinic acid in aqueous medium which functioned as a fuel, decomposed the metal complexes at low temperature, and yielded the free impurity LiNi0.5Co0.5O2 compounds. Thermal (TG–DTA) analyses and XRD data show that powders grown with a layered structure ( space group) have been obtained at temperatures below 400°C by the acidification reaction of the aqueous solutions. The local structure of synthesized products was characterized by Fourier transform infrared (FTIR) spectroscopy. The electrochemical properties of the synthesized products were evaluated in rechargeable Li cells using a non-aqueous organic electrolyte (1 M LiClO4 in propylene carbonate, PC). The LiNi0.5Co0.5O2 positive electrodes fired at 600°C exhibited good cycling behavior

Removal Efficiency of Textile Dyes from Aqueous Solutions Using Calcined Waste of Eggshells as Eco-friendly Adsorbent: Kinetic and Thermodynamic Studies

This research investigates the removal of textile dyes (Rhodamine B and Alizarin Red S) from aqueous solution by a low-cost adsorbent prepared from eggshell waste. Batch adsorption experiments were conducted in order to determine the effect of different parameters such as pH, dye concentration, contact time, adsorbent dosage, particle size, and temperature. The best correlation was found by Langmuir model, and the maximum adsorption capacity was 175.58 mg g–1 for Rhodamine B and 156.56 mg g–1 for Alizarin Red S. Thermodynamic studies showed that the adsorption of Rhodamine B and Alizarin Red S were feasible, spontaneous, and exothermic in nature. Regeneration study conducted to test the reusability (five cycles) and comparison of adsorption capacities of Rhodamine B and Alizarin Red S showed that calcined eggshell adsorbent could potentially be used for the removal of dyes from aqueous solutions. This work is licensed under a Creative Commons Attribution 4.0 International License

Fractional Supersymmetry As a Matrix Model

Using parafermionic field theoretical methods, the fundamentals of 2d fractional supersymmetry ${\bf Q}^{K} =P$ are set up. Known difficulties induced by methods based on the $U_{q}(sl(2))$ quantum group representations and non commutative geometry are overpassed in the parafermionic approach. Moreover we find that fractional supersymmetric algebras are naturally realized as matrix models. The K=3 case is studied in details. Links between 2d $({1\over 3},0)$ and $(({1\over 3}^{2}),0)$ fractional supersymmetries and N=2 U(1) and N=4 su(2) standard supersymmetries respectively are exhibited. Field theoretical models describing the self couplings of the matter multiplets $(0^{2},({1\over 3})^{2},({2\over 3})^{2})$ and $(0^{4},({1\over 3})^{4},({2\over 3})^{4})$ are given.Comment: Latex,no figure,17page

NC Effective Gauge Model for Multilayer FQH States

We develop an effective field model for describing FQH states with rational filling factors that are not of Laughlin type. These kinds of systems, which concern single layer hierarchical states and multilayer ones, were observed experimentally; but have not yet a satisfactory non commutative effective field description like in the case of Susskind model. Using $D$ brane analysis and fiber bundle techniques, we first classify such states in terms of representations characterized, amongst others, by the filling factor of the layers; but also by proper subgroups of the underlying $U(n)$ gauge symmetry. Multilayer states in the lowest Landau level are interpreted in terms of systems of $D2$ branes; but hierarchical ones are realized as Fiber bundles on $D2$ which we construct explicitly. In this picture, Jain and Haldane series are recovered as special cases and have a remarkable interpretation in terms of Fiber bundles with specific intersection matrices. We also derive the general NC commutative effective field and matrix models for FQH states, extending Susskind theory, and give the general expression of the rational filling factors as well as their non abelian gauge symmetries.Comment: 54 pages 11 figures, LaTe

Empirical investigation to explore potential gains from the amalgamation of Phase Changing Materials (PCMs) and wood shavings

The reduction of gained heat, heat peak shifting and the mitigation of air temperature fluctuations are some desirable properties that are sought after in any thermal insulation system. It cannot be overstated that these factors, in addition to others, govern the performance of such systems thus their effect on indoor ambient conditions. The effect of such systems extends also to Heating, Ventilation and Air-conditioning (HVAC) systems that are set up to operate optimally in certain conditions. Where literature shows that PCMs and natural materials such as wood-shavings can provide efficient passive insulation for buildings, it is evident that such approaches utilise methods that are of a degree of intricacy which requires specialist knowledge and complex techniques, such as micro-encapsulation for instance. With technical and economic aspects in mind, an amalgam of PCM and wood-shavings has been created for the purpose of being utilised as a feasible thermal insulation. The amalgamation was performed in the simplest of methods, through submerging the wood shavings in PCM. An experimental procedure was devised to test the thermal performance of the amalgam and compare this to the performance of the same un-amalgamated materials. Comparative analysis revealed that no significant thermal gains would be expected from such amalgamation. However, significant reduction in the total weight of the insulation system would be achieved that, in this case, shown to be up to 20.94%. Thus, further reducing possible strains on structural elements due to the application of insulation on buildings. This can be especially beneficial in vernacular architectural approaches where considerably large amounts and thicknesses of insulations are used. In addition, cost reduction could be attained as wood shavings are significantly cheaper compared to the cost of PCMs

Triticum durum var KEBIR

L'objectif de cette recherche est d'étudier l'effet de la salinité du sol par différents niveaux de NaCl (0, 10, 15 g/L) sur certaines propriétés morphologiques et physiologiques du blé dur Triticum durum var KEBIR au stade de la croissance, et la possibilité de le réduire en appliquant une phytohormone la kinétine avec des concentrations (10, 20, 30 mg/L) par pulvérisation foliaire.Les résultats obtenus des propriétés morphologiques montrent que la longueur de la tige et la surface foliaire augmentent proportionnellement avec le degré de la salinité âpres pulvérisation de la kinétine. Concernant les propriétés physiologiques, l'application de cette hormone sur les plantes stressées induit une augmentation proportionnelle de la teneur en chlorophylle (a) et (b) avec la concentration de sel utilisée.Une augmentation de la teneur en proline est observée dans les plantes traitées ou non par l'hormone la kinétine. Mots cles: Salinité- Triticum durum var KEBIR- Phytohormones- Kinétine - Pulvérisation foliaire. The aim of this work is to study the effect of soil salinity using different levels of NaCl (0, 10, 15 g/L) on some morphological and physiological properties of durum wheat Triticum durum var KEBIR in the stage of growth. The possibility to reduce salinity it by one of the phytohormones: kinetin with concentrations of (10, 20, 30 mg/L) through the foliar spray is also studied. The results of morphological properties show that the stem length and the leaf area increase proportionally with the degree of salinity after spraying kinetin. Concerning the physiological properties, the application of this hormone in plants under stress induced a proportional increase in chlorophyll (a) and (b) with the concentration of used salt. Similarly, an increase of proline content is observed in the plants treated or not treated by kinetin.Keywords: Salinity- Triticum durum var KEBIR- Phytohormones- Kinetin- Foliar spray

1-phenyl-5-mercapto-1,2,3,4-tétrazole (PMT) : un nouvel inhibiteur de corrosion de l'alliage Cu-Zn efficace à très faible concentration

L'inhibition de la corrosion de l'alliage Cu-Zn (70/30) en milieu H2SO4 0.1 M par des composés organiques de type “tétrazole" a été étudiée en utilisant les méthodes gravimétrique et électrochimique. Les résultats obtenus montrent que le 1-phényl-5-mercapto-1,2,3,4-tétrazole (PMT) est le meilleur inhibiteur de la série tétrazole étudiée. L'efficacité inhibitrice du PMT croît avec sa concentration et atteint 93 % dès 10-6 M et 99 % à 10-3 M. L'effet de la température (20–90 °C) sur le comportement de Cu-Zn dans H2SO4 0,1 M seul et avec addition de 10-4 M de PMT a été étudié et les énergies d'activation correspondantes ont été déterminées