Partially isolated four port converter with combined PWM and secondary phase shift control

A partially isolated four-port converter is proposed in this paper for interfacing two renewable sources and a storage device with an isolated load. This converter is capable of achieving high power density because of the effective sharing of devices among the input ports. Combined PWM and secondary phase shift control is employed to have a decoupled power flow management of input and output side ports. PWM control is used at the input side for maximum power tracking of renewable sources and battery power management. At the output side, secondary Phase shift control is used for controlling the output voltage. The adopted secondary phase shift control allows the primary switching legs to be operated with 1800 phase shift which results in reduced current ripple at input ports. The working principle of the converter, its output characteristics and control strategy are discussed. Working of the converter and its control strategy is verified through simulation for different input and output conditions. Further, to validate the simulation results, the experimental results of a 500W prototype are also provided

Oral Hygiene Practices: Ancient Historical Review

The ancient history of the world’s fascination with oral health is a long and illustrious one. Numerous dental epidemiological studies indicate that people are keeping their teeth longer than over before in this century. Neolithic age and prehistoric age people used agents and devices that have evolved, by custom, myth, beliefs and by research, to enable people, withprofessional assistance, to maintain good oral health. The first mentions of teeth and dental hygiene were found in inscriptions from Mesopotamian clay tablets, so called ‘oral hygieneproducts’ including toothpicks, chewing sticks, tooth powders and mouthwashes, dating back to 5,000 years ago. The Egyptians, Mesopotamians’, Greco-Romans, Hindus and Chinese discovered variety of dental treatments and intricate surgical operations. The profession has met the challenge by developing and perfecting a myriad of devices and agents tothwart these pathogenic factors since ages. We certainly eat well, speak well, look fine and ‘smell fresh’–but we also have plaque, gingivitis and dental caries. The reader can determinehow much our ancestors thought, invented and practiced oral hygiene long long ago and which gave raise to later inventions

A survey on power management strategies of hybrid energy systems in microgrid

The power generation through renewable energy resources is increasing vastly, Solar energy and Wind Energy are the most abundantly available renewable energy resources. The growth of small scale distributed grid networks increasing rapidly in the modern power systems and Distributed Generation (DG) plays a predominant role. Microgrid is one among the emerging techniques in power systems. Power Management is mainly required to have control over the real and reactive power of individual DG and for smooth operation, maintaining stability and reliability. This paper presents a survey of the research works already reported focusing on power management of hybrid energy systems such as mainly solar and wind systems in microgrid. Six different approaches have been studied in detail for AC,DC and hybrid AC/DC microgrid

Weaving ‘figured - face flip face - fabric’ using orthogonal weft tapestry weave

The aim of this study is to evolve new compound weave structures by modifying and permuting the existing structures. Basic principles of orthogonal structure and weft tapestry structure have been studied. New ‘Orthogonal Weft Tapestry (OWT)’ weaves are evolved by combining these two weaves and the concepts involved in deriving the new weave have also been developed. The structure of ‘Two in one’ figured fabric available in the field has been analyzed. This fabric is renamed as ‘Figured - Face Flip Face - Fabric (FFFFF)’. Suitability of OWT weave to produce diversified FFFFF has been interpreted. Superimposing the guide graphs for the preparation of weave graph has been worked out using MS Paint to weave this fabric using electronic jacquard. Methodology of making double punching graph for mechanical jacquard weaving is also explored. The feasibilities of weaving these structures are explored using heald-treadle and jacquard shedding devices either separately or in combination. Fabric samples have been developed using mechanical jacquard in handloom. The techno - ergonomics of weaving methods are compared and recorded. It is observed that FFFFF produced with OWT weave has got features like uniqueness in appearance, fascinating utility value, and possibilities of producing exclusive product range

Weaving twill damask fabric using ‘section- scale- stitch’ harnessing

The possibility of weaving figured twill damask using the combination of ‘sectional-scaled- stitched’ (SSS) harnessing systems has been explored. Setting of sectional, pressure harness systems used in jacquard have been studied. The arrangements of weave marks of twill damask using the warp face and weft face twills of 4 threads have been analyzed. The different characteristics of the weave have been identified. The methodology of setting the jacquard harness along with healds has been derived corresponding to the weave analysis. It involves in making the harness / ends in two sections; one section is to increase the figuring capacity by scaling the harness and combining it with other section of simple stitching harnessing of ends. Hence, the new harness methodology has been named as ‘section-scale-stitch’ harnessing. The advantages of new SSS harnessing to weave figured twill damask have been recorded. It is observed that the new harnessing methodology has got the advantages like increased figuring capacity with the given jacquard, less strain on the ends and versatility to produce all range of products of twill damask. It is also found that the new harnessing is suitable to weave figured double cloth using interchanging double equal plain cloth, extra warp and extra weft weaving

HYDROGEOCHEMICAL QUALITY OF GROUNDWATER IN PERUMAL LAKE, KURINJIPADI TALUK, CUDDALORE DISTRICT, TAMILNADU, INDIA

A study was carried out to determine the groundwater quality in parts of Perumal Lake, Kurinjipadi Taluk, Cuddalore district, Tamilnadu. Totally, 12 groundwater samples were collected at different parts of study area and 16 water samples from surface reservoirs (Perumal lake) and analyzed for physicochemical parameters (pH, EC, TDS, TH, Na, K, Ca, Mg and Cl, SO4 , HCO3- , NO3 ) in order to understand the hydro geochemistry of the water. The results of analysis were interpreted with geology and geomorphology of the area and also by various geochemical diagrams such as Piper trilinear plot and USSL classification diagram. Suitability of this water for its utility was verified using Indian standards. The result indicates irrespective of the seasons that only one well is suitable for drinking purpose, with remaining suitable for domestic and irrigation purpose. Further, from the results, it is pointed out that most of the well water falls in Na-Cl type indicating the influence of seawater in these wells which was confirmed by Piper plot. According to SAR (alkali hazard) and specific conductance (Salinity hazard) is plotted in USSL diagram, classification of water for irrigation purpose can be determined. Majority of groundwater samples fall in C3S1 zone indicating high salinity and low sodium hazard, satisfactory for plants having moderate salt tolerance on soils. In surface water most of the samples fall in C2S1 indicates medium salinity and low sodium hazard

Synthesis, antioxidant and antibacterial activities of quinoline incorporated 2,4,5trisubstituted imidazole derivatives

1601-1606A series of quinoline incorporated 2,4,5-trisubstituted imidazole derivatives (4a-h and 5a-f) have been synthesized. The structures of the synthesized compounds have been established by FT-IR, 1H NMR and mass spectral analysis. The prepared compounds have been evaluated for their in vitro antioxidant activity by DPPH method and antibacterial activity against Bacillus subtilis, Escherichia coli, Bacillus megaterium and Salmonella typhi bacterial strains at 500 µg/mL concentration. The compounds 4a, 4e and 4d exhibit good antioxidant activity. Among the synthesized compounds, 4a has shown significant antibacterial activity against all the three tested microorganisms