Designing power system stabilizer for multimachine power system using neuro-fuzzy algorithm

This paper describes a design procedure for a fuzzy logic based power system stabilizer (FLPSS) and adaptive neuro-fuzzy inference system (ANFIS) and investigates their robustness for a multi-machine power system. Speed deviation of a machine and its derivative are chosen as the input signals to the FLPSS. A four-machine and a two-area power system is used as the case study. Computer simulations for the test system subjected to transient disturbances i.e. a three phase fault, were carried out and the results showed that the proposed controller is able to prove its effectiveness and improve the system damping when compared to a conventional lead-lag based power system stabilizer controller

A Ka-Band Horn Antenna Excited With Parasitic Dielectric Resonator Antenna

A pyramidal horn antenna excited with parasitic dielectric resonator (DR) antenna for use at Ka-band frequencies is proposed

An Efficient Parallel Quarter-sweep Point Iterative Algorithm for Solving Poisson Equation on SMP Parallel Computer

A new point iterative algorithm which uses the quarter-sweep approach was shown to be much faster than the full-and half- sweep point iterative algorithms for solving two dimensional Poison equation (Othman el at. 1998». However, the last two algorithms were found to be suitable for parallel implementation (Evans 1984) and Ali el at. (1997». In this paper, the parallel implementation of the new algorithm with the chessboard (CB) strategy on Symmetry Multi Processors (SMP) parallel computer was presented. The experimental results of a test problem were compared with the later two parallel algorithms

A novel Multi-permittivity Cylindrical Dielectric Resonator Antenna for Wideband Applications

In this paper, a novel multi-permittivity cylindrical dielectric resonator antenna for wideband application is presented. The multi-permittivity cylinder is formed by combining two different permittivity material sectors in such a way that each sector (with constant permittivity) is 90 degree apart. A direct microstrip line coupling terminated with T-stub at the open end is used to excite the multi-permittivity cylindrical dielectric resonator. The angular position of the multi sector dielectric resonator with respect to the longitudinal axis of the microstrip line and length of the additional strip at the open end of the feeding circuit is key parameters for wideband operation of the antenna. By optimizing all parameters of the proposed antenna, wideband impedance bandwidth of 56% (12.1 GHz - 21.65 GHz) is achieved. The average gain of the antenna throughout the bandwidth is 5.9 dB with good radiation properties in both E-plane and H-plane. A well matched simulation and experimental results show that the antenna is suitable for wideband applications

Optimization of copper for the improvement of in vitro plant tissue growth of Solanum nigrum

Here was investigated the incorporation of copper in MS medium on growth, and metabolic activities of Solanum nigrum callus. Copper up to 75 µM increased the growth, and thereafter a decline was observed. No considerable alteration in MDA, H2O2, bound phenolics, flavonoids, ascorbate, and copper content was observed with the existence of 25 µM copper, then levels of these parameters were raised with rising copper concentrations. Similarly, 25 µM copper didn't induce a considerable change in lipoxygenase, superoxide dismutase, catalase, peroxidase, phenylalanine ammonia lyase, and polyphenol oxidase activities, however, high levels stimulated these enzymes. Copper at 25 µM didn’t considerably reduce amino acids and soluble proteins, whereas higher concentrations reduced these parameters. Copper treatments reduced the soluble carbohydrates accumulation; only 75 µM enhanced this accumulation. Copper at 25 µM significantly increased the potassium accumulation, whereas higher concentrations reduced this accumulation. From these results, it might be contemplated the optimum effect concerning copper. DOI: http://dx.doi.org/10.5281/zenodo.284864

Design Minkowski Shaped Patch Antenna with Rectangular Parasitic Patch Elements for 5.8 GHz Applications

Abstract—This paper presents the parametric study on the Minkowski shaped antenna with the rectangular parasitic patch elements. This patch antenna consists four parts – patch, feed line, ground plane and parasitic elements. The rectangular parasitic patch elements are located at the bottom of the Minkowski shaped patch. The parametric study of different patch sizes (Design 2A, Design 2B, Design 2C, Design 2D and Design 2E) is presented in this paper. The antenna parameters studied in this paper are resonant frequencies, return loss at the resonant frequency, bandwidth and realized gain. The target frequency of this antenna is 5.80 GHz for Worldwide Interoperability for Microwave Access (WiMAX) application. It shows the return loss of – 24.477 dB, bandwidth of 254 MHz (5.676 GHz to 5.930 GHz) and a gain of 2.351 dB. Index Terms—Minkowski; patch antenna; gain; return loss; bandwidt

The Preventive Effects of Urtica dioica ‎Extract and Nanoparticle on Oxidative Stress ‎and Lipid Profile in Hyperlipidemic Male ‎Rats

Cardiovascular diseases are the major factor in human premature death and disability and they are becoming more common worldwide. Individual atherosclerosis risk factors such obesity, hypertension, hyperlipidemia, diabetes, and smoking all lead to an increase in oxidative stress. As a result, oxidative stress is thought to be a major factor in the development of atherosclerosis. Heart disease risk factors that have been well-documented include elevated blood lipid levels. Significant gaps in the treatment of CVDs still exist, in addition to making healthy lifestyle changes and using lipid-lowering medications as part of primary CVD prevention and therapy regimens. Natural extracts are a rich source of biomolecules that can be used as complex reagents for the biogenic synthesis of silver nanoparticles as well as antioxidant medicines or dietary supplements. The current study estimates the anti-oxidant and protective activity of Urica dioica 200mg/kg extract water and ethanol with its silver nanoparticles 15mg/kg on lipid profile in induced hyperlipidemia rats feeding on high fat diet then evaluate lipid profile and MDA, SOD and GSH of the serum after 40 days, also characterization of AgNPs done by UV-Vis absorption, FTIR, XRD and SEM. The result demonstrates that the successful synthesis of NPs and Urtica dioica has a favorable impact on lipid profile and can function as a good antioxidant that can be employed as a protective agent against rising lipids and oxidative stress. However, further research studies need to investigate the safety and activity of different dose of AgNPS of Urtica dioica

Pregnancy outcome after one previous caesarean section at a tertiary university teaching hospital in Tanzania

The aim of this study was to assess outcome of pregnancy in women with one previous caesarean section at Muhimbili National Hospital in Dar es Salaam, Tanzania. A cross sectional descriptive study was conducted at Muhimbili National Hospital (MNH) from 13th September 2006-2nd February 2007. All women with one previous caesarean section coming for delivery at MNH in that period were identified. Data on medical history, socio-demographic and obstetric characteristics, decision on mode of delivery, and pregnancy outcomes were collected. There were 3285 deliveries during the study period, out of which 365 (11%) women had one previous caesarean section. Almost half (48%) of the women with one previous caesarean section attended antenatal care in the dispensaries and health centres. Trial of scar was decided in 80 (21.9%) women. A total of 278 women had the decision for repeat caesarean section made on admission whereby 180 (64.4%) were for emergency caesarean section and 98 (35.6%) were for elective caesarean section. A total 52 women delivered vaginally, 44 after trial of the scar and eight among women decided for emergency repeat caesarean section on admission. The incidence of uterine rupture was 2% and perinatal mortality ratio was 55 per 1000 live birth. In conclusion, a significant proportion of women delivering at MNH had one previous caesarean section among which few underwent trial of scar. Half of the women attended antenatal care in the dispensaries and health centres. Women with previous caesarean section should be encouraged to attend hospitals providing comprehensive emergency obstetric care. The quality of intrapartum monitoring should be audited to improve maternal and newborn outcome