• 제목/요약/키워드: RAMA

검색결과 169건 처리시간 0.021초

Improved Modification of the Closed-Loop-Controlled AC-AC Resonant Converter for Induction Heating

  • Dhandapani, Kirubakaran;Sathi, Rama Reddy
    • ETRI Journal
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    • 제31권3호
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    • pp.298-303
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    • 2009
  • A single-switch parallel resonant converter for induction heating is implemented. The circuit consists of an input LC-filter, a bridge rectifier, and a controlled power switch. The switch operates in soft commutation mode and serves as a high frequency generator. The output power is controlled via the switching frequency. A steady state analysis of the converter operation is presented. A closed-loop circuit model is also presented, and the experimental results are compared with the simulation results.

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Techniques for dental implant nanosurface modifications

  • Pachauri, Preeti;Bathala, Lakshmana Rao;Sangur, Rajashekar
    • The Journal of Advanced Prosthodontics
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    • 제6권6호
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    • pp.498-504
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    • 2014
  • PURPOSE. Dental implant has gained clinical success over last decade with the major drawback related to osseointegration as properties of metal (Titanium) are different from human bone. Currently implant procedures include endosseous type of dental implants with nanoscale surface characteristics. The objective of this review article is to summarize the role of nanotopography on titanium dental implant surfaces in order to improve osseointegration and various techniques that can generate nanoscale topographic features to titanium implants. MATERIALS AND METHODS. A systematic electronic search of English language peer reviewed dental literature was performed for articles published between December 1987 to January 2012. Search was conducted in Medline, PubMed and Google scholar supplemented by hand searching of selected journals. 101 articles were assigned to full text analysis. Articles were selected according to inclusion and exclusion criterion. All articles were screened according to inclusion standard. 39 articles were included in the analysis. RESULTS. Out of 39 studies, seven studies demonstrated that bone implant contact increases with increase in surface roughness. Five studies showed comparative evaluation of techniques producing microtopography and nanotopography. Eight studies concluded that osteoblasts preferably adhere to nano structure as compared to smooth surface. Six studies illustrated that nanotopography modify implant surface and their properties. Thirteen studies described techniques to produce nano roughness. CONCLUSION. Modification of dental osseous implants at nanoscale level produced by various techniques can alter biological responses that may improve osseointegration and dental implant procedures.

Evaluation and Identification of Promising Bivoltine Hybrids of Silk-worm, Bombyx mori L., for Tropics

  • Rao, P.Sudhakara;Singh, Ravindra;Kalpana, G.V.;Naik, V.Nishitha;Basavaraja, H.K.;Swamy, G.N.Rama;Datta, R.K.
    • International Journal of Industrial Entomology and Biomaterials
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    • 제3권1호
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    • pp.31-35
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    • 2001
  • Ten newly evolved bivoltine hybrids of silkworm (Bombyx mori L) were evaluated with control hybrid KA${\pm}$NB4D2 during three seasons of a year for their seasonal performance. Analysis of variance and other statistical methods were employed and the performance was observed in respect of 10 quantitative traits. The results showed significant genotype${\pm}$environment interaction with respect to four quantitative characters viz. fecundity, yield/10,000 larvae, filament length and raw silk (%). Environmental effects were significant for nine characters out of ten characters evaluated. A 105${\pm}$J2 and B${\pm}$NB4D2 were considered as highly adaptable hybrids to local conditions with high mean for maximum characters studied and found suitable to rear in all seasons.

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Power Flow Control of a Multi-bus/Three-feeder Distribution System Using Generalized Unified Power Quality Conditioner

  • Mohammed, B.S.;Ibrahim, R.;Perumal, N.;Rao, K.S. Rama
    • Journal of Electrical Engineering and Technology
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    • 제10권1호
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    • pp.8-17
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    • 2015
  • This paper analyses the power flow of a three-feeder/multi-bus distribution system by a custom Generalized Power Quality Conditioner (GUPQC). The GUPQC has been realized by three voltage source converters (VSCs) coupled back-to-back through a common DC-link capacitor on the DC-side. One feeder was controlled by the shunt compensator, whereas each of the other two feeders was controlled by the proposed novel series compensator. The GUPQC has the capability to simultaneously compensate voltage and current quality problems of a multi-bus/three-feeder distribution system. Besides that, the power can be transferred from one feeder to other feeders to compensate for poor power quality problems. Extensive simulation studies were carried out by using MATLAB/SIMULINK software to establish the ability of the GUPQC to improve power quality of the distribution systems under distorted supply voltage conditions.

Self-rated ability to follow instructions for four mental states described in yoga texts

  • Ramachandra, Raghavendra Bhat;Telles, Shirley;Hongasandra, Nagendra Rama Rao
    • 셀메드
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    • 제2권3호
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    • pp.28.1-28.4
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    • 2012
  • There were no studies available measuring the ability to follow instructions for meditation. Hence, the present study was planned to assess the ability to follow instructions for the four mental states viz., cancalata (random thinking), ekagrata (non-meditative concentration), dharana (focused meditation) and dhyana (defocused meditation or effortless meditation) described in yoga texts. Sixty male volunteers with ages ranging from 18 to 31 years (group mean age ${\pm}$ S.D., $22.78{\pm}2.73$) participated in the study. They were assessed using a visual analog scale immediately after each of the four states on four different days. The results showed that following dharana, scores on the visual analog scale were significantly lower compared to those related to cancalata, ekagrata and dhyana. Hence, dharana is the most difficult of the four states.

Multi-objective optimal design of laminate composite shells and stiffened shells

  • Lakshmi, K.;Rama Mohan Rao, A.
    • Structural Engineering and Mechanics
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    • 제43권6호
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    • pp.771-794
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    • 2012
  • This paper presents a multi-objective evolutionary algorithm for combinatorial optimisation and applied for design optimisation of fiber reinforced composite structures. The proposed algorithm closely follows the implementation of Pareto Archive Evolutionary strategy (PAES) proposed in the literature. The modifications suggested include a customized neighbourhood search algorithm in place of mutation operator to improve intensification mechanism and a cross over operator to improve diversification mechanism. Further, an external archive is maintained to collect the historical Pareto optimal solutions. The design constraints are handled in this paper by treating them as additional objectives. Numerical studies have been carried out by solving a hybrid fiber reinforced laminate composite cylindrical shell, stiffened composite cylindrical shell and pressure vessel with varied number of design objectives. The studies presented in this paper clearly indicate that well spread Pareto optimal solutions can be obtained employing the proposed algorithm.

Control of phosphoric acid induced volume change in clays using fly ash

  • Chavali, Rama Vara Prasad;Reddy, P. Hari Prasad
    • Geomechanics and Engineering
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    • 제15권6호
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    • pp.1135-1141
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    • 2018
  • Volume changes of soils induced by inorganic acids cause severe foundation and superstructure failures in industrial buildings. This study aimed to assess the potential of fly ash to control volume changes in soils under acidic environment. Two soils such as black cotton soil predominant with montmorillonite and kaolin clay predominant with kaolinite were used for the present investigation. Both soils exhibited an increase in swelling subjected to phosphoric acid contamination. Ion exchange reactions and mineralogical transformations lead to an increase in swelling and a decrease in compressibility in black cotton soil, whereas phosphate adsorption and mineral dissolution lead to an increase in swelling and compressibility in case of kaolin clay. Different percentages of Class F fly ash obtained from Ramagundam national thermal power station were used for soil treatment. Fly ash treatment leads to significant reduction in swelling and compressibility, which is attributed to the formation of aluminum phosphate cements in the presence of phosphoric acid.