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Studies on Reduction of Yarn Hairiness by Nozzles in Ring Spinning and Winding by Airflow Simulation
Rengasamy R. S.,Patnaik Asis,Punekar Hemant The Korean Fiber Society 2006 Fibers and polymers Vol.7 No.3
Reduction of yam hairiness by nozzles in ring spinning and winding is a new approach. Simulation of the airflow pattern inside the nozzles provides useful information about actual mechanism of hairiness reduction. The swirling air current inside the nozzles is capable of wrapping the protruding hairs around the yam body, thereby reducing yam hairiness. Since production rate of winding is very high and the process itself increases yarn hairiness any method to reduce the hairiness of yarns at this stage is a novel approach. A CFD (computational fluid dynamics) model has been developed to simulate the airflow pattern inside the nozzles using Fluent 6.1 software. In this study, both S- and Z-type nozzles having an axial angle of 500 and diameter of 2.2 mm were used for simulation studies. To create a swirling effect, four air holes of 0.4 mm diameter are made tangential to the inner walls of the nozzles. S- and Z-twisted yams of 30 tex were spun with and without nozzles and were tested for hairiness, tensile and evenness properties. The total number of hairs equal to or exceeding 3 mm (i.e. the S3 values) for yam spun with nozzle is nearly 49-51 % less than that of ring yams in case of nozzle-ring spinning, and 15 % less in case of nozzle-winding, while both the yarn types show little difference in evenness and tensile properties. Upward airflow gives best results in terms of hairiness reduction for nozzle-ring and nozzle wound yams compared to ring yarns. Yarn passing through the centre of the nozzle shows maximum reduction in S3 values.
Dynamic Friction of Polyester Air-jet Textured Yarns
Rengasamy Raju Seenivasan,Guruprasad Raghavendran,Asis Patnaik The Korean Fiber Society 2005 Fibers and polymers Vol.6 No.2
In this paper, friction of air-jet textured yams is investigated. Using a friction measuring apparatus fabricated inhouse, dynamic friction forces of the yams under yarn-to-metal (YM) and yam-to-yam (YY) rubbing modes are measured. The influence of processing variables of air-jet texturing viz., overfeed, air pressure, dry/wet texturing and normal/core-and-effect texturing on dynamic friction is analysed. The results indicate that friction force increases with increasing rubbing speeds and yam input tension. YM dynamic friction decreases initially and then starts to increase at higher overfeeds. YY dynamic friction increases with increasing overfeed. YM dynamic friction decreases with an increase in air pressure while an opposite trend is observed for YY friction. Wet textured yams have higher friction than dry textured yams. Core wetted coreand-effect textured yams have higher friction than normal textured yams.
Rengasamy, Tamilarasan,Arun, Anand Prabu,Muniswamy, Raajenthiren,Mahendradas, Dharmendira Kumar,Yoo, Chang Kyoo The Society of Chemical Engineers, Japan 2009 Journal of chemical engineering of Japan Vol.42 No.7
<P>This communication presents the effect of five dissolved inorganic salts (sodium chloride, NaCl; calcium chloride, CaCl<SUB>2</SUB>; zinc chloride, ZnCl<SUB>2</SUB>; cadmium chloride, CdCl<SUB>2</SUB>; ammonium chloride, NH<SUB>4</SUB>Cl) on the enthalpy of mixing (<I>H</I><SUP>E</SUP>) of ethyl acetate/benzene binary system at 303.15 K; enthalpy measurements were performed using an isothermal displacement calorimeter with vapor space. The excess enthalpy of mixing of this system is significantly reduced in the presence of NH<SUB>4</SUB>Cl and NaCl; however, changes in the excess enthalpy of mixing were insignificant in the presence of CaCl<SUB>2</SUB>, ZnCl<SUB>2</SUB>, and CdCl<SUB>2</SUB>. The experimental values of <I>H</I><SUP>E</SUP> were fitted into the Redlich–Kister equation, and deviations from the ideal value and binary parameters were calculated. The importance of solute–solvent interactions was demonstrated from the decrease in the excess enthalpy of mixing in the negative direction with an increase in the NaCl concentration.</P>
Stereoselective Synthesis of L-Deoxyaltronojirimycin from L-Serine
Rengasamy, Rajesh,Curtis-Long, Marcus J.,Ryu, Hyung-Won,Oh, Kyeong-Yeol,Park, Ki-Hun Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.7
(2S,3R)-3-Hydroxy-2-(hydroxymethyl)-3,6-dihydro-2H-pyridine 8, an important precursor for the synthesis of polyhydroxylated piperidine azasugars, has been prepared from L-serine. Highly stereoselective nucleophilic addition to amino aldehyde 5 gave the corresponding allylic alcohol 6 which proceeded to give dihydro-2H-piridine 7a via a Grubbs II catalyzed RCM. Stereoselective H-bond directed epoxidation of allylic alcohol led to the oxiranyl alcohol 9 which was easily converted to L-deoxyaltronojirimycin by regioselective ring opening.
Stereoselective Synthesis of L-Deoxyaltronojirimycin from L-Serine
Rajesh Rengasamy,Hyung Won Ryu,Kyeong Yeol Oh,박기훈,Marcus J. Curtis-Long 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.7
(2S,3R)-3-Hydroxy-2-(hydroxymethyl)-3,6-dihydro-2H-pyridine 8, an important precursor for the synthesis of polyhydroxylated piperidine azasugars, has been prepared from L-serine. Highly stereoselective nucleophilic addition to amino aldehyde 5 gave the corresponding allylic alcohol 6 which proceeded to give dihydro-2H-piridine 7a via a Grubbs II catalyzed RCM. Stereoselective H-bond directed epoxidation of allylic alcohol led to the oxiranyl alcohol 9 which was easily converted to L-deoxyaltronojirimycin by regioselective ring opening.
Toxicological Evaluation of Fucoidan from Cladosiphon okamuranus
T. Paul Gideon,R. Rengasamy 한국식품영양과학회 2008 Journal of medicinal food Vol.11 No.4
Fucoidans are sulfated polysaccharides extracted from brown seaweeds. They have a wide spectrum of activity in biological systems. Besides their well-known anticoagulant and anti-thrombotic activity, fucoidans modulate inflammation, possess antiproliferative and anti-adhesive effects on cells, protect cells from viral infection, and interfere with mammalian fertilization. Fucoidans are now used as raw material for development of drugs and are also widely used as a health-promoting food component. However, studies on the toxicity of fucoidans from different brown algae are limited. The present study examined the acute toxicity of varying levels of fucoidan extracted from Okinawa mozuku, a brown alga (Cladosiphon okamuranus), in Wistar rats after oral administration. No significant toxicological changes were induced by fucoidan at a dose of 600 mg/kg of body weight/day. However, with concentrations at and above 1,200 mg/kg of body weight/day, clotting time was significantly prolonged. No other signs of toxicity were observed.
Feeding the extra billions: strategies to improve crops and enhance future food security
Stamm, Petra,Ramamoorthy, Rengasamy,Kumar, Prakash P. The Korean Society of Plant Biotechnology 2011 Plant biotechnology reports Vol.5 No.2
The ability to feed an expanding world population poses one of the greatest challenges to mankind in the future. Accompanying the increased demand for food by the expected nine billion inhabitants of Earth in 2050 will be a continual decrease in arable land area, together with a decline in crop yield due to a variety of stresses. For these formidable challenges to be met, future crops should not only by high-yielding, but also stress-tolerant and disease-resistant. In this review, we highlight the importance of genetic engineering as an indispensable tool to generate just such future crops. We briefly discuss strategies and available tools for biotechnological crop improvement and identify selected examples of candidate genes that may be manipulated so that current biological maxima in yield may be surpassed by comfortable margins. Future prospects and the necessity for basic research aimed at identifying novel target genes are also discussed.
Cho, Jung-Keun,Rengasamy, Rajesh,Curtis-Long, Marcus John,Kim, Jin-Hyo,Lee, Ji-Won,Park, Ki-Hun The Korean Society for Applied Biological Chemistr 2011 Applied Biological Chemistry (Appl Biol Chem) Vol.54 No.6
Azasugars derived from L-alanine and L-serine were screened for inhibitory activity against ${\alpha}$-rhamnosidase. The enantiomers of 1,6-dideoxynojirimycin ($ent$-1,6-dDNJ) (1) and ($2S$,$3R$)-2-(hydroxymethyl)piperidin-3-ol (5) showed highly specific and potent inhibition against ${\alpha}$-rhamnosidase with $K_i$ values of 4.2 and $16.6{\mu}M$, respectively. Structure of the best inhibitor features the same stereochemical configuration as L-rhamnose at C2, C3, and C4 centers. In kinetic studies, both compounds exhibited competitive inhibition behavior. Compound 1 manifested simple reversible slow-binding inhibition with the following kinetic parameters: ${\kappa}_3=1.17nM^{-1}\;min^{-1}$, ${\kappa}_4=5.96{\times}10^{-3}min^{-1}$, and $K_i^{app}$=5.1 mM.
Lipeeka Rout,Prashanth Rengasamy,Basanti Ekka,Aniket Kumar,Priyabrat Dash 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.4
We report the synthesis of TiO2-supported monometallic Ag, Sn and bimetallic AgSn nanoparticle catalysts prepared using sol–gel method via a rational nanoparticle encapsulation route. The samples were thoroughly characterized by ultraviolet-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) with image mapping and Brunauer–Emmett–Teller (BET) surface area analyzer. The supported bimetallic AgSn catalyst had the anatase structure, surface area of 50 m2 /g and 2.6 ± 0.6 nm particle size. The efficiency of the catalysts was evaluated on photodegradation of methylene blue (MB) dye under visible light. The photocatalytic activity of MB was significantly enhanced in the presence of bimetallic AgSn nanoparticles (NPs) as compared to individual metal nanoparticles. Reusability study of the photocatalyst showed that the catalyst can be reused upto 5 runs with minimal loss in activity. Kinetic study revealed that the degradation reaction follows a pseudo first-order pathway.