Special type of three-phase oscillator using current gain control for amplitude stabilization
The main aim of this work is to demonstrate the use of electronically controlled second-generation current conveyor in providing electronic control to the condition of oscillation (CO) of a new active RC sinusoidal oscillator. Electronic control of the CO, which is independently set and does not affect the oscillation frequency, is enabled by the use of an auxiliary amplitude control loop to regulate the amplitude and...
Variational iteration algorithm-II for solving linear and non-linear ODEs
Variational iteration method is widely used for solving linear and non-linear ODE. In this paper, the variational iteration algorithm-II is constructed and some examples are given to show its simple solution procedure and high accuracy of the obtained results. Key words: Variational iteration method, series solution, ordinary differential equations.
Characterisation of impulse noise effects on space-time block-coded orthogonal frequency division multiplexing (OFDM) signal reception
This correspondence presents the characterisation of impulse noise effects on the space-time block-coded orthogonal-frequency-division-multiplexing (STBC-OFDM) symbol reception, in which the conventional OFDM system is combined with the antenna-diversity/spatial-diversity in order to achieve the high data transmission rates. The weak impulse noise may be combated by the longer OFDM symbol duration, in which the total...
Mapping extensible markup language document with relational database management system
The extensible markup language (XML) is designed for data representation with conciseness, generalization, and usability through the internet, however, this technology requires an appropriate medium for the storage of data. The approach, named XRecursive, is proposed to store and retrieve XML documents using relational database, which is applied to all internal nodes mapped by Schema-oblivious, and all the leaf...
Seasonal variations in groundwater quality: A statistical approach
In this study, a descriptive statistical measure and a partial correlation analysis were applied to groundwater quality data set monitored in pre-monsoon and post-monsoon for three years to investigate seasonal variations of Central Ganga Plain in India. The variables were divided into two categories as “chemical property- HCO3, Cl, SO4, Na, K, Ca, and Mg” and “physical property- electrical...
Design and performance of photovoltaic power system as a renewable energy source for residential in Khartoum
This paper discussed the efficient system of sustainable renewable energy for domestic used and its total cost. The method of this paper was the collection of the basic data of solar radiation, wind speed and other required input data, and then hybrid optimization simulation model was developed using the electric renewable energy software hybridoptimization model of renewable energy (HOMER). Simulation model has...
Generation of surface optical vortices by evanescent Bessel beams
We present that a set of high order Bessel beams when internally reflected at a dielectric/vacuum interface can create distinct evanescent light modes in each of which the intensity distribution is restricted to a sub-wavelength region near the interface outside the dielectric. We believe that this could really facilitate lateral optical manipulation of nano-particles and neutral atoms along the interface....