Modeling and simulation of a 3-ф induction motor based on two types of WFA

This paper has been proposed to simulate the transient model of 3-Ф cage rotor induction motor based on winding function approach (WFA). According to this method the motor is assumed to be consist of an electrical circuits on both stator and rotor. The magneto motive forces (MMF) that have been generated by these circuits play a role for coupling them together. Then mutual and self-inductances will be easily computed using WFA. Two types of WFA have been used to build and simulate the model of the induction motor. In the one part type, it’s assumed that the coupling MMF between stator and rotor have a non-sinusoidal shapes according to the actual windings distribution over the motor slots. While in second part type the generated MMF in are assumed to have sinusoidal waveform. The suggested models may be used to simulate the dynamic as well as steady state performance of a faulty and non-faulty motor. A simulation of the suggested models that consists of m-rotor bars and n-stator phases multiple coupled circuit-based has been performed using matlab m.file and the results of the motor current have been proved in its nonlinear way by using WFA

Performance investigation of stand-alone induction generator based on STATCOM for wind power application

Self-Excited induction generators (SEIG) display a low voltage and frequency regulation due to variable applied load and input rotation speed. Current work presents a simulation and performance analysis of a three-phase wind-driven, SEIG connect to a three-phase load. In addition, an investigation of the dynamic operation of the induction generator from starting steady state until no-load operation. It is assumed that the input mechanical power is constant where the rotor of the SEIG rotates at a constant speed. The value of the excitation capacitance which is necessary to the operation of the induction generator also computed to ensure a smooth and self-excitation starting. The output voltage of the generator is adjusted by varying the reactive power injected by STATCOM. A 3-phase IGBT voltage source inverter with a fuel cell input supply is connected as STATCOM which is used to compensate for the reduction in the supply voltage and its frequency due to variation occurred in the applied loads. This work includes introducing a neuro-fuzzyy logic controller to enhance the performance of the SEIG by regulation the generated voltage and frequency The dynamic model of SEIG with STATCOM and loads are implemented using MATLAB/SIMULIN

Pathological Nipple discharge: a comparison between breast ultrasound and mammography

Background:Nipple discharge is a relatively common complaint of females in reproductive age and after menopause. Objectives: The aim of this stud was to compare the radiological findings of mammography and ultrasound in women with pathological nipple discharge of different pathology.  Methods:  mammography and ultrasound was done for a total of 50 patients attending the National center of Early detection of Breast cancer with pathological nipple discharge. Ultrasound guided FNA was performed for all cases, and histopathology was available for eleven case. Results: ultrasound was able to provide clue of possible underlying cause for all pathological nipple discharge whereas mammography was negative in 54%. Ultrasound was more sensitive in diagnosing malignant breast lesions associated with pathological nipple discharge (85.7%) but less specific (88.3%) as compared with mammography which had (71.4%) sensitivity and (90.6%) specificity. Negative predictive value of ultrasound was 97.4% , mammography was 95.1% and of non-bloody nipple discharge was 94%. Conclusion: Ultrasound is essential to complete pathological nipple discharge workup, particularly when mammography is normal, to rule out the possibility of neoplastic changes and to provide clues for nonneoplastic etiology that may guide the management

Deploying Municipal Solid Waste Management 3R-WTE Framework in Saudi Arabia: Challenges and Future

The need for resilience and an agile waste management system in Saudi Arabia is vital to control safely the rapid growth of its municipal solid waste (MSW) with minimal environment toll. Similarly, the domestic energy production in Saudi Arabia is thriving and putting a tremendous pressure on its huge reserves of fossil oil. Waste to energy (WTE) plants provides a golden opportunity for Saudi Arabia; however, both challenges (MSW mitigation and energy production) are usually looked at in isolation. This paper at first explores the potential of expanding the WTE energy production in the eastern province in Saudi Arabia under two scenarios (complete mass burn with and without recycling). Secondly, this study analyzes the effect of 3Rs (reduce, reuse, recycle) practices implementation in a residential camp (11,000 population) to influence the behavior of the camp’s citizens to reduce their average waste (kg/capita). The results of the 3R-WTE framework show a potential may reach 254 Megawatt (MW) of electricity by year 2030. The 3R system implementation in the camp reduced MSW production from 5,625 tons to 3000 tons of household waste every year, which is considered lower than what the surrounding communities to be produced in the same area