Comparative Study of PI Controller and PID Controller for Power Quality Improvement

Power factor correction (PFC) is a mandatory functionality of electronic products in the industrial and commercial market in order to mitigate grid harmonics to improve power quality. Since the load characteristics of most PFC applications such as home appliances, battery chargers, switched mode power supplies and other digital products support unidirectional power flow, the general ac - dc boost converter is considered a popular topology. It is one of the low cost, simple methodologies and their performance is well - proven. Maintaining dc - link voltage constantly inside the system in order to feed loads at different power ratings is the main task. Active power filters (APF) is another approach capable of improving grid power quality to control input current with a pure sinusoidal waveform in phase with input voltage. Unlike PFC circuits, the APF is a system in itself which provides compensation of harmonics and reactive power in order to reduce undesirable effects from non-linear loads and uncontrolled passive loads in power systems. The paper introduces a versatile method for mitigating grid power quality using unidirectional ac ? dc boost converter. The additional focus of this paper is to measure the quantity of input current distortions by the unidirectional ac ? dc boost converter used for supplying active power to the load and reactive power. By using this method, the amount of reactive power injected due to input current distortion from an individual converter to the grid should be restricted. This paper presents, control strategy by using dual boost PFC converter. An improved simulation software using MATLAB was developed to study the proposed method to mitigate harmonics in order to improve power quality. Comparative results for power quality improvement by using PI controller and PID controller are observed

Design and Implementation of Wireless Environment Monitoring System

This paper describes the development of a sustainable power source that can supply sufficient power to wireless sensors in remote locations while requiring less maintenance and low costs. The soil energy is utilized by Microbial Fuel Cell. The soil with microorganisms can produce energy when they are attached with two electrodes, one positive and another negative electrode. This leads to flow of electrons contributing to electricity. The electricity is then utilized to Electronic circuit consisting of microcontroller and the humidity and temperature sensors are attached to it to read out the values of temperature and humidity on PC by using ZigBee Transceiver.Â

Performance Evaluation of Kiln for Cashew Nut Shell Carbonization and Liquid.

Abstract Cashew nut shell (CNS) was utilized for carbonization in developed prototype kiln. Prototype kiln was evaluated with direct and indirect methods and characteristics of CNS and CNS char were determined by proximate and ultimate analysis. The maximum CNS temperatures obtained inside the kiln during direct and indirect method were recorded as 452.2℃ and 458.8℃ respectively. Maximum oil percentage, charcoal percentage and ash percentage in direct method were observed as 21.1 per cent, 21.04 per cent and 3.34 per cent respectively whereas 23.8 per cent, 18.3 per cent and 1.27 per cent in indirect method respectively. Hydrogen content in CNS was found about 6 to 7 per cent and nitrogen content in CNS was found about 0.70 to 0.75 per cent. Oxygen content in CNS was observed about 29 to 31 percent. Carbon, hydrogen and nitrogen content of the CNS char were observed in the range of 73 to 76 per cent, 4 to 5 per cent and 1 to 2 per cent respectively. It was found that nitrogen content has increased in CNS char after the carbonization of CNS. Oxygen content in the CNS char gets reduced to 13 to 14 percent, which was comparatively very less than CNS. It was observed that indirect method is more suitable for carbonization than direct method for obtaining higher calorific value char and maximum fixed carbon percentage as found in cashew nut shell char as 60 per cent

Design and development of radio tomographic imaging system

Radio tomographic imaging (RTI) is an emerging imaging technique that utilizes the shadowing losses on links between multiple pairs of wireless nodes within the monitoring area to estimate the attenuation of physical objects. In recent years, RTI has gained huge interest from the researchers in device-free localization (DFL) field due to its ability in generating an image to localize a target within the monitoring area. From the literature studies, researchers are primarily focused on the study of characterizing RSSI attenuation for different purposes such as human presence detection, privacy-preserving localization, indoor and outdoor localization. However, to the best of the authors' knowledge, there is no research conducted in studies the effects of phantoms with different dimensions towards the changes in received signal strength indicator (RSSI) value. Therefore, this paper presents a design and development of the RTI system to study and characterize the behaviour of radio waves propagation when phantoms with different dimensions are present within the monitoring area. An overview of the proposed RTI system, the arrangement of sensor arrays and a few factors that should take into consideration when using the RF sensors such as ground effects, near field and far-field region of an antenna have been discussed in this paper. Also, the details of the experimental design have been explained. Based on the results obtained from the experiments, the RSSI value decreases gradually as the dimension of phantoms with water medium increases. This is because when the diameter of a phantom with water medium increased, the water content inside the phantom also increased. Also, water is a high-attenuating medium and its dielectric constant is 80. Therefore, when the diameter of a phantom with water medium increased, the energy of the EM waves is absorbed and scattered more. This caused the attenuation of EM waves increased and resulted in lower RSSI value

Oxidative Stress in Wild Boars Naturally and Experimentally Infected with Mycobacterium bovis

Reactive oxygen and nitrogen species (ROS-RNS) are important defence substances involved in the immune response against pathogens. An excessive increase in ROS-RNS, however, can damage the organism causing oxidative stress (OS). The organism is able to neutralise OS by the production of antioxidant enzymes (AE); hence, tissue damage is the result of an imbalance between oxidant and antioxidant status. Though some work has been carried out in humans, there is a lack of information about the oxidant/antioxidant status in the presence of tuberculosis (TB) in wild reservoirs. In the Mediterranean Basin, wild boar (Sus scrofa) is the main reservoir of TB. Wild boar showing severe TB have an increased risk to Mycobacterium spp. shedding, leading to pathogen spreading and persistence. If OS is greater in these individuals, oxidant/antioxidant balance in TB-affected boars could be used as a biomarker of disease severity. The present work had a two-fold objective: i) to study the effects of bovine TB on different OS biomarkers (namely superoxide dismutase (SOD), catalasa (CAT), glutathione peroxidase (GPX), glutathione reductase (GR) and thiobarbituric acid reactive substances (TBARS)) in wild boar experimentally challenged with Mycobacterium bovis, and ii) to explore the role of body weight, sex, population and season in explaining the observed variability of OS indicators in two populations of free-ranging wild boar where TB is common. For the first objective, a partial least squares regression (PLSR) approach was used whereas, recursive partitioning with regression tree models (RTM) were applied for the second. A negative relationship between antioxidant enzymes and bovine TB (the more severe lesions, the lower the concentration of antioxidant biomarkers) was observed in experimentally infected animals. The final PLSR model retained the GPX, SOD and GR biomarkers and showed that 17.6% of the observed variability of antioxidant capacity was significantly correlated with the PLSR X's component represented by both disease status and the age of boars. In the samples from free-ranging wild boar, however, the environmental factors were more relevant to the observed variability of the OS biomarkers than the TB itself. For each OS biomarker, each RTM was defined as a maximum by one node due to the population effect. Along the same lines, the ad hoc tree regression on boars from the population with a higher prevalence of severe TB confirmed that disease status was not the main factor explaining the observed variability in OS biomarkers. It was concluded that oxidative damage caused by TB is significant, but can only be detected in the absence of environmental variation in wild boar

Thermal Analysis of Solar Tunnel Dryer and Evaluation for Commercial Mango Leather Drying

A walk-in type semi-cylindrical shaped solar tunnel dryer (10 m x 3.75 m) was designed, developed and evaluated at Dr. B.S. Konakan Krishi Vidyapeeth, Dapoli for thermal analysis. The dryer was evaluated by conducting no-load test at laboratory to study the thermal profile, energy input/output during the winter and summer season. Based on the laboratory experience, a commercial scale solar tunnel dryer was installed and evaluated at M/s Shirodkar Food Products Pvt. Ltd., kudal, District Sindhudurg (MS) for commercial mango leather drying. The dryer was loaded with 250 kg mango pulp per batch by spreading over 210 number of grease-proof aluminium trays (1.2 kg pulp in each tray) in three layers (70 trays in each layer). Drying of mango leather was studied in comparison with open sun drying and electrical oven drying for time saving and energy consumption. The study revealed that the average rise in temperature of drying air was about 18 -22 0C over the ambient air. The average drying period reduced by 28 % over open sun drying method. The average temperature inside the solar dryer was 62+5 0C, and required 10 h for upper layer of trays, 13 h for second layer of trays, and 17 h for third level of trays as compared to 26 h in open sun drying. The operating energy cost of solar tunnel dryer was zero as compared to 102 kWh in electrical oven. Considering drying of 30 batches per season, the payback period of the system was 2.7 years

Study of ocular manifestations in pediatric human immunodeficiency virus according to national acquired immunodeficiency syndrome patients in a tertiary care hospital

Introduction: Ocular involvement in children with HIV AIDS most commonly include allergic conjunctivitis, herpes zoster ophthalmicus,molluscum contagiosum, retinal vasculitis, CMV retinitis and isolated cotton wool spots. Materials and Methods: Non comparative prospective study was conducted at a tertiary care hospital from January 2015 to December 2015. A total of 506 patients of upto 12 years of age, affected with HIV AIDS, attending ART centre of the institute, were thoroughly examined for ocular involvement. Preliminary history which includes blurring of vision , deviation of eyes, night blindness or any other ocular complaints was documented. Detailed ocular examination was done thoroughly. Patient's ART case sheet was also referenced to know about any systemic conditions like tuberculosis, pneumocystis pneumonia, kaposi's sarcoma etc. Patients' most recent CD4 count was also documented. Results: Out of 506 children examined, 140 were found to have ocular involvement (27.6%). Anterior segment findings were found in 14.8% whereas retinal and optic nerve findings were found in 12.45% of patients. Ocular manifestations were also co-related with the CD4 count of the patients which showed that lower CD4 counts is significantly associated with increased ocular involvement. Conclusion: Our study concludes that the most common ocular manifestations in paediatric HIV patients include retinal perivasculitis, allergic conjunctivitis, herpes zoster ophthalmicus and dry eye and also demonstrates that ocular involvement is significantly associated with lower CD4 counts