Dimmable electronic ballasts by variable power density modulation technique

Dimming can be accomplished commonly by switching frequency and pulse density modulation techniques and a variable inductor. In this study, a variable power density modulation (VPDM) control technique is proposed for dimming applications. A fluorescent lamp is operated in several states to meet the desired lamp power in a modulation period. The proposed technique has the same advantages of magnetic dimming topologies have. In addition, a unique and flexible control technique can be achieved. A prototype dimmable electronic ballast is built and experiments related to it have been conducted. As a result, a 36WT8 fluorescent lamp can be driven for a desired lamp power from several alternatives without modulating the switching frequency.     

Optimal data collection design in machine learning: the case of the fixed effects generalized least squares panel data model

Machine Learning - This work belongs to the strand of literature that combines machine learning, optimization, and econometrics. The aim is to optimize the data collection process in a specific...     

Symbolic Regression Based Extreme Learning Machine Models for System Identification

Neural Processing Letters - Reproducible machine learning models with less number of parameters and fast optimization are preferred in embedded system design for the applications of artificial...     

Preparation,characterization, and in vitro bioactivity of Bixa orellana extract-impregnated collagen microspheres

Collagen microspheres usually have particle size lesser than 200 µm, which are characteristically free-flowing powders of protein. They can overcome some of the conventional therapy problems and enhance therapeutic efficacy due to their biocompatible and biodegradable nature. Collagen microspheres were prepared using the fish Lates calcarifer scale collagen and were loaded with Bixa orellana plant extract. The Bixa orellana plant extract-loaded collagen microsphere was characterized for its physico-chemical properties using Fourier-transform infrared, Raman spectra, X-ray diffraction, scanning electron microscopy, and particle size analysis, and in vitro plant extract release. This plant extract showed good antimicrobial property against Staphylococcus aureus and Escherichia coli. The in vitro anticancer activity of the prepared material was carried out using MCF-7 cell lines which showed 83.46 % of cell death at 1000 µg/well. Anticancer effect of the prepared material can be enhanced by increasing the concentration of plant extract in the composite.     

Influence of spinning parameters on synthesis of alumina fibres by centrifugal spinning

The present study investigates the synthesis of alumina fibres of 5–15?µm dia. by sol-gel process through centrifugal spinning. Among various spinning parameters such as rpm, viscosity, humidity, chamber temperature etc., effect of rpm and viscosity on quality of spun fibres was examined in order to spin less defective (less shots) fibres. From the rpm vs viscosity experiments, it was concluded that viscosity between 13 and 42?Pa.s with 3000?rpm was favourable for obtaining fibres containing less shots. It was shown that besides viscosity, refractive index and percent weight loss of the aged sol can be used as indicator for determining spinnability of alumina precursor sols. Influence of only preheating and continuous heating of the chamber during spinning were also investigated and it was found that only preheating did not help in producing fibres. Besides this, influence of hot air blower (HAB) aligned in different directions with respect to the spinnerette, on fibre quality was tested. It was observed that the quality of fibres did not change due to change in HAB direction.     

HYDROGEN RESOURCES : CONVERSION OF BLACK LIQUOR TO HYDROGEN RICH GASEOUS PRODUCTS

Two precipitates were obtained from original black liquor by using hydrochloric acid and carbon dioxide. The precipitates were liqufied and gasificated by non-catalytic and catalytic runs at gradually elevated temperatures. The amount of gaseous products increased with increasing temperature and percent of catalyst. The percent of hydrogen in the obtained gas mixture was the highest in potassium carbonate catalytic runs (37 %).     

Morphological and histological structure of the male reproductive system of the water strider Gerris lacustris (Linnaeus 1758) (Gerridae,Heteroptera)

This work presents the male reproductive system morphology and histology of the water strider Gerris lacustris (Linnaeus 1758) (Gerridae, Heteroptera) using light microscopy and scanning electron microscopy. The male reproductive system of G. lacustris comprise of a pair of testes, two vasa deferentia, two seminal vesicles, an ejaculatory duct. There is no bulbus ejaculatorius and the long vas deferantia uniting to form a simple ductus ejaculatorius which is connected to the aedeagus. The testes are white colored and this cylindiric‐shaped structure lies along genital abdominal segment. The testicular follicles have three different development zones (growth zone, maturation zone, differentiation zone). Each testis has two follicles, which are not lined by a common peritoneal sheath and involving many cysts arranged in a progressive order of maturation from the distal to the proximal region; spermiogenesis occurs in mature males, finishing with the organization of sperm bundles. The testes are connected to the seminal vesicles, specialized sperm storage places, by the vas deferentia.     

PEM fuel cell supported distribution static compensator for power quality enhancement in three-phase four-wire distribution system

One of the major problems in electrical power system is the lack of quality of power due to the rapid growth of nonlinear load and unbalanced load utilization in three-phase four-wire distribution system. In this paper, PEM (Proton Exchange Membrane) fuel cell supported four-leg Distribution Static Compensator (DSTATCOM) is modelled to mitigate harmonics, neutral current and load balancing under nonlinear load and unbalanced load conditions in three-phase four-wire distribution system. The instantaneous reactive power (IRP) theory control algorithm is proposed for four-leg DSTATCOM. The Real coded Genetic Algorithm (RGA) optimized Proportional Integral (PI) controller and Adaptive Neuro Fuzzy Inference System (ANFIS) controller are used for regulating the DC link voltage of DSTATCOM. This paper also investigates the performance of ANFIS based DSTATCOM with conventional method. The proposed system is modelled and its performance is analyzed in MATLAB/SIMULINK.