Modelling and Simulation of Doubly-Fed Induction Generator Connected with Wind Turbine

This work presents the modelling of DFIG (Doubly-Fed Induction Machine) using active and reactive power transfer model and the controlling strategy of DFIG using multivariable control method. This paper also represents the free acceleration characteristics of the machine. Real/Reactive powers are used in the matrix as state variables. Multi -loop control scheme is used for the control. The controller part uses six compensators. The matrix method used this paper increased the robustness of the machine as power waveforms are independent of d-q reference variable. The simulation of modelling and controlling is done using MATLAB/SIMULINK and the waveforms are plotted

Evaluation of residence time on nitrogen oxides removal in non-thermal plasma reactor

Non-thermal plasma (NTP) has been introduced over the last few years as a promising after- treatment system for nitrogen oxides and particulate matter removal from diesel exhaust. NTP technology has not been commercialised as yet, due to its high rate of energy consumption. Therefore, it is important to seek out new methods to improve NTP performance. Residence time is a crucial parameter in engine exhaust emissions treatment. In this paper, different electrode shapes are analysed and the corresponding residence time and NOx removal efficiency are studied. An axisymmetric laminar model is used for obtaining residence time distribution numerically using FLUENT software. If the mean residence time in a NTP plasma reactor increases, there will be a corresponding increase in the reaction time and consequently the pollutant removal efficiency increases. Three different screw thread electrodes and a rod electrode are examined. The results show the advantage of screw thread electrodes in comparison with the rod electrode. Furthermore,between the screw thread electrodes, the electrode with the thread width of 1 mm has the highest NOx removal due to higher residence time and a greater number of micro-discharges. The results show that the residence time of the screw thread electrode with a thread width of 1 mm is 21% more than for the rod electrode

Studies on Compact Discharge Plasma Source for NOX Treatment in Engine Exhaust

This paper proposes a compact electric discharge plasma source for controlling NOX emission in diesel engine exhaust. An automobile ignition coil was used to generate the high voltage pulse using flyback topology. This design is aimed at retrofitting the existing catalytic converters with pulse assisted cleaning technique. In this paper we bring out a relative comparison of discharge plasma and plasma-adsorbent process at different gas flow rates. Activated alumina was used as adsorbent. The main emphasis is laid on the development of a compact pulse source from a DC supply for the removal of NOX from the filtered diesel engine exhaust

Studies on NOX Removal From Diesel Engine Exhaust Using Duct-Type DBD Reactor

With ever more stringent NOX emissions, it is necessary to examine removal of nitrogen oxide from diesel engine exhaust. This paper describes the study of NOX reduction from 5.9-kW stationary diesel engine exhaust under nanosecond pulse energization. Two plasma reactors characterized by dielectric barrier discharge has been designed, built, and evaluated. One of the reactor designs include nine numbers of electrodes kept in parallel, and the exhaust was allowed to pass axially, whereas the second reactor consists of nine parallel electrodes and the exhaust was allowed to pass radially. The reactors were individually tested for the treatment of nitrogen oxides for gas flow rate of 2, 5, and 10 L/min. Both the reactors have been individually tested, and results show an appreciable removal of NOX with equal discharge volume. From the results, it was found that both the reactors were an efficient NOX removal. With consumption of only 36 J/L, the reactors had shown a considerable 45% DeNO(X) efficiency

Portable HVAC and Pulsed Plasma Sources for Control of NOX in Diesel Engine Exhaust

In this paper studies were carried out on two compact electric discharge plasma sources for controlling nitrogen oxides (NOX) emission in diesel engine exhaust. The plasma sources consist of an old television flyback transformer to generate high frequency high voltage ac (HVAC) and an automobile ignition coil to generate the high voltage pulses (HV Pulse). The compact plasma sources are aimed at retrofitting the existing catalytic converters with electric discharge assisted cleaning technique. To enhance NOX removal efficiency cascaded plasma-adsorbent technique has been used. Studies were reported at different flow rates and load conditions of the diesel engine

Cascaded Cross Flow DBD-Adsorbent Technique for NOX Abatement in Diesel Engine Exhaust

In this paper, a different type of cross flow dielectric barrier discharge (DBD) reactor was designed and tested. Here the gas flow is perpendicular to the barrier discharge electrode. Discharge plasma was utilized to oxidize NO contained in the exhaust gas to NO2 and subsequent NO2 removal can be improved using an adsorbent system. A detailed study of DeNO(X) in a stationary diesel engine exhaust was carried out using pulsed electrical discharges/adsorbent processes. Activated alumina (Al2O3) and MS-13x were used as adsorbents at room temperature. The main emphasis is laid on the removal of NOX from the filtered diesel engine exhaust. In filtered exhaust environment, the cross flow reactor along with adsorbent exhibits a superior performance with regard to NOX removal when compared to that with axial flow of gas. In this paper we bring out a relative comparison of discharge plasma and plasma-adsorbent process at various gas flow rates, ranging from 2 l/min to 25 l/min. The discharge plasma-adsorbent assisted barrier discharge reactor has shown promising results in NOX removal at high flow rates

Dielectric Barrier Discharge Cascaded with Red Mud Waste to Enhance NOX Removal from Diesel Engine Exhaust

Red mud is a waste by-product generated during the processing of bauxite, the most common ore of aluminium. With the presence of ferric oxide, high surface area, resistance to poisoning and low cost, red mud made itself a good alternative to the existing commercial automobile catalyst. The cascading of dielectric barrier discharge plasma with red mud improved the NOX removal from diesel engine exhaust significantly. The DeNO(X) efficiency with discharge plasma was 74% and that with red mud was 31%. The efficiency increased to 92% when plasma was cascaded with red mud catalyst operating at a temperature of 400 degrees C. The NOX removal was dominated by NO2 removal. The studies were conducted at different temperatures and the results were discussed

NO(X) abatement from filtered diesel engine exhaust using battery-powered high-voltage pulse power supply

The dielectric barrier discharg

Predictors of over-the-counter medication: A cross-sectional Indian study

Context: The determinants of over-the-counter (OTC) medication need to be understood to design adequate drug information policies. Aim: To determine the prevalence and predictors of OTC medication among the adult population of Berhampur town in Odisha, India. Settings and Design: It was a prospective, cross-sectional, observational study carried out in the private retail pharmacy on a convenience sample of 880 adults over a period of 6 months at Berhampur, Odisha, India. Materials and Methods: Medication use behavior was explored using a data collection form that had three parts. The first part captured data on the sociodemographic characteristics of drug consumers. The second and third part collected data on drug history and attitude toward the available health-care facility, respectively. Statistical Analysis: Descriptive statistics was used to represent the prevalence of OTC medication. Odds ratio and 95% confidence intervals (CIs) were used to determine the predictors of OTC medication. Results: The overall prevalence of OTC medication use was 18.72% (95% CI: 15.34–47.16%). Younger age, male gender, lower income, and poor lifestyle were the predictors of OTC medication. Perception of poor accessibility to health care, the presence of chronic diseases and having a symptom count of more than two significantly increased the likelihood of OTC medication (P < 0.05). Conclusions: Sociodemographic profile, drug history, and attitude toward health-care availability in the locality can predict OTC medication behavior. Interventions aimed at changing the perceptions of the public regarding accessibility, affordability of the health care is likely to influence OTC medication behavior and make it safer