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Singapore, Singapore

Yadav G.N.B.,Singapore Polytechnic | Narasamma N.L.,Indian Institute of Technology Madras
IEEE Transactions on Power Electronics | Year: 2014

A novel active soft switched phase-shifted full-bridge (PSFB) dc-dc converter is presented in this paper. An auxiliary circuit is added to the pulse width modulation counterpart to achieve the soft switching. The proposed circuit achieves soft switching for both main and auxiliary switches, without increasing the main device current/voltage rating. The auxiliary circuit is gated appropriately in order to achieve zero voltage switching for lagging leg. Tapping in the primary winding of power transformer is added for the purpose of commutation. The proposed circuit is capable of operating at elevated switching frequencies of several hundreds of kilohertz in a range of line and load variations. Steady-state analysis and evaluation of losses for the proposed circuit is presented. Analytical models valid for steady state and dynamic performance are proposed. A 350-W, 100-kHz active soft switched PSFB dc-dc converter prototype is implemented. The proposed analytical models are validated experimentally on 350-W prototype. Experimental results verifying steady state and dynamic models are presented. © 1986-2012 IEEE. Source


Leong J.,Singapore Polytechnic | Leong J.,Massey University | Morel P.C.H.,Massey University | Purchas R.W.,Massey University | Wilkinson B.H.P.,Massey University
Meat Science | Year: 2010

Garlic essential oil (GEO) added directly to pork mince or to the diet of pigs was evaluated for its effectiveness in masking undesirable mutton flavour. Pork was from 31 female pigs (Duroc × (Large White × Landrace)) grown on diets containing either animal-plus-plant products (AP diet) or plant products only (P diet) with four levels of GEO: 0, 0.55, 1.44 and 1.84 g/kg feed and 0, 0.55, 1.44 and 2.15 g/kg feed in the AP and P diet, respectively. Garlic flavour increased and mutton flavour decreased in pork from pigs that consumed more than about 150 g and 220 g of GEO in P and AP diets, respectively over the 57-day feeding period. The garlic flavour was stronger and the mutton flavour less intense for pork from pigs on the P diet. When GEO was added to pork mince at 125 ppm, it significantly reduced mutton flavour. © 2009 Elsevier Ltd. All rights reserved. Source


Pok K.-Y.,11 Health | Lai Y.-L.,11 Health | Sng J.,Singapore Polytechnic | Ng L.-C.,11 Health
Vector-Borne and Zoonotic Diseases | Year: 2010

Early and accurate diagnosis of dengue is imperative for disease surveillance, which helps in the control of dengue in endemic countries. In this study, we evaluated the performance of three commercially available dengue nonstructural 1 (NS1) antigen assays (Bio-Rad Platelia™ Dengue NS1 Antigen ELISA, PanBio Dengue Early ELISA, and Bio-Rad Dengue NS1 Antigen Strip test) and compared them with reverse-transcription polymerase chain reaction (RT-PCR) and other commercially available serological assays for the diagnosis of dengue. The analysis showed RT-PCR to be the most sensitive and specific (100%) diagnostic method during the first 3 days of fever. The overall sensitivity of dengue NS1 antigen assays within the same period was 81.7%, indicating their potential role as a cost-effective and convenient alternative method to RT-PCR for the diagnosis of dengue fever in a primary healthcare setting. However, reduced sensitivity in detecting secondary dengue infections was one of the drawbacks of dengue NS1 antigen assays. Nonetheless, it remains a useful assay for the early detection of dengue and hence could play an important role in routine surveillance efforts to control dengue outbreaks in Singapore. © Copyright 2010, Mary Ann Liebert, Inc. 2010. Source


Patent
Agency For Science, Ngee Ann Polytechnic, Temasek Polytechnic and Singapore Polytechnic | Date: 2013-05-20

A surface on a polymeric film having an array of patterned structures, wherein the array of patterned structures influences fluid flow of the surface and causes reduced attachment of a biological material.


Loh X.J.,Institute of Materials Research and Engineering of Singapore | Ong S.J.,Singapore Polytechnic | Tung Y.T.,Singapore Polytechnic | Choo H.T.,Singapore Polytechnic
Macromolecular Bioscience | Year: 2013

The synthesis and gene transfection efficiency of a series of novel amphiphilic triblock copolymers with two hydrophilic poly(2-(dimethylamino)ethyl methacrylate) (DMAEMA) blocks flanking a central hydrophobic poly[(R)-3-hydroxybutyrate] (PHB) block is reported. These copolymers have significantly lower toxicity compared to the polyethyleneimine (PEI) and PDMAEMA homopolymer. Unexpectedly, the incorporation of PHB significantly improves the gene transfection efficiency as compared to PEI or PDMAEMA homopolymers. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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