Genetic Algorithm Based Control System Design of a Self-Excited Induction Generator

This paper presents an application of the genetic algorithm (GA) for optimizing controller gains of the Self-Excited Induction Generator (SEIG) driven by the Wind Energy Conversion Scheme (WECS). The proposed genetic algorithm is introduced to adapt the integral gains of the conventional controllers of the active and reactive control loop of the system under study, where GA calculates the optimum value for the gains of the variables based on the best dynamic performance and a domain search of the integral gains. The proposed genetic algorithm is used to regulate the terminal voltage or reactive power control, by adjusting the self excitation, and to control the mechanical input power or active power control by adapting the blade angle of WECS, in order to adjust the stator frequency. The GA is used for optimizing these gains, for an active and reactive power loop, by solving the related optimization problem. The simulation results show a better dynamic performance using the GA than using the conventional PI controller for active and reactive control

Neurospora tetraspora D. Garcia, Stchigel & Guarro (= Gelasinospora tetrasperma Dowding) as a first record to Egypt

An interesting isolate of homothallic, ascosporic filamentous fungus having 4-spored asci, was recovered once from a non-rhizosphere soil sample collected from a grapevine plantation in the village of El-Khawaled, Sahel-Saleem city, Assiut. It was isolated on DYM agar plate at 25°C in June 2008. The isolate was identified phenotypically and genotypically as Neurospora tetraspora (= Gelasinospora tetrasperma) and was deposited in the culture collection of Assiut University Mycological Centre as AUMC no. 6784 and ITS gene sequence of the strain was deposited at the National Center for Biotechnology Information (NCBI) and assigned a GenBank accession number JQ425383. N. tetraspora is being recorded in the current work for the first time in Egypt. By this addition, the genus is now known in Egypt by four species. A key is provided for the four species. DOI: http://dx.doi.org/10.5281/zenodo.116560

Izrada i značajke tankih polikristaliničnih hetero-spojeva n-Cd0.9Zn0.1S/p-CuGa0.3In0.7Se2

CuGa0.3In0.7Se2 polycrystalline thin films were prepared by thermal evaporation under vacuum of about 10-4Pa, with a deposition rate of about 200 nm/min. The selenization of these films at 723 K improves their properties. The activation energy as well as the optical energy gap of the investigated samples decreased with annealing and selenization. Polycrystalline thin film n-Cd0.9Zn0.1S/p-CuGa0.3In0.7Se2 heterojunctions were fabricated and the current density - voltage and capacitance - voltage characteristics of the junction were studied. The heterojunctions were exposed to light, and under illumination of 1000 mWcm-2, the open circuit voltage was 580 mV, the short circuit current density 4.8 mAcm-2, the fill factor 0.682 and the electrical conversion efficiency was 1.898% for cells of active area of 1 cm2.Tanke polikristalinične slojeve CuGa0.3In0.7Se2 pripremali smo naparavanjem u vakuumu oko 10−4 Pa, brzinom polaganja oko 200 nm/min. Seleniranje tih slojeva na 723 K poboljšava im svojstva. Aktivacijska energija i optički energijski procijep smanjuju se opuštanjem i seleniranjem. Pripremali smo i polikristalinične tankoslojne hetero-spojeve n-Cd0.9Zn0.1S/p-CuGa0.3In0.7Se2 i proučavali njihova značajke: gustoća struje – napon i kapacitet – napon. Ćelije ploštine 1 cm2 heterospojeva osvijetlili smo svjetlošću jakosti 1000 mW/cm2 i izmjerili napon otvorenog kruga od 580 mV, gustoću struje kratkog spoja 4.8 mAcm−2 , faktor punjenja 0.682 i učinkovitost pretvorbe 1.898%

Power System Stabilizer Driven by an Adaptive Fuzzy Set for Better Dynamic Performance

This paper presents a novel application of a fuzzy logic controller (FLC) driven by an adaptive fuzzy set (AFS) for a power system stabilizer (PSS).The proposed FLC, driven by AFS, is compared with a classical FLC, driven by a fixed fuzzy set (FFS). Both FLC algorithms use the speed error and its rate of change as input vectors. A single generator equipped with FLC-PSS and connected to an infinite bus bar through double transmission lines is considered. Both FLCs, using AFS and FFS, are simulated and tested when the system is subjected to different step changes in the reference value. The simulation results of the proposed FLC, using the adaptive fuzzy set, give a better dynamic response of the overall system by improving the damping coefficient and decreasing the rise time and settling time compared with classical FLC using FFS. The proposed FLC using AFS also reduces the computational time of the FLC as the number of rules is reduced.

Co-Production of Cellulase and Xylanase Enzymes By Thermophilic Bacillus subtilis 276NS

Co-production of thermostable extracellular cellulase and xylanase was investigated using bacterial soil isolate. To evaluate the effect of culture conditions on the c-oproduction of both enzymes by Bacillus subtilis 276NS (GenBank accession number JF801740), a Plackett-Burman fractional factorial design was applied. Among the tested variables, yeast extract, sucrose and incubation time were the most significant variables increased cellulase and xylanase productions. Both of xylan and CMC (Carboxymethyl Cellulose) induced the xylanse enzyme production. A near-optimum medium formulation was obtained which increased the cellulase and xylanase enzymes 5.7- and 1.08 –fold higher than the yield obtained with the basal medium, respectively. Thereafter, the response surface methodology was adopted to acquire the best process conditions among the selected variables (xylan, CMC and Yeast Extract (YE)) required for improving xylanase yield. The optimal combinations of the major medium constituents for xylanase production evaluated using non-linear optimization algorithm of EXCEL-solver, was as follows (g/L): D-sucrose, 10; xylan, 10.367, CMC, 10.535; (NH4)2SO4, 1.0; YE, 1.71; Tween-80, 0.4 and FeSO4, 0.25 mg/L, at pH 8.0, temperature 35◦C and incubation time 24h under shaking. The predicted optimum thermostable xylanase activity was 360 U/ml, which was around 4-times the activity with the basal medium