http://hdl.handle.net/123456789/192 CCR Sun, 19 Apr 2026 00:39:09 GMT 2026-04-19T00:39:09Z http://hdl.handle.net/1/94 Title: Synthesis and Kinetic Studies of Rigid Polyurethane Foam Based on Modiied Castor Oil Authors: Vashisht, Urvashi; Kaushal, Jyotsna Abstract: Castor oil based diethanolamine modiied rigid polyurethane (PU) foam formation and its reaction rate kinetics have been studied during the present work. Physico-chemical properties of the synthesized base polyol such as acid value, hydroxyl value and viscosity have been measured. Rigid (PU) foam processing parameters such as mixing time, cream time, gel time, rise time and tack free time were measured at temperature 220C and 70% humidity. Rigid foam kinetic investigations with different catalysts such as triethylene diamine (TEDA), diethyl methylamine (DEMA), triethylamine (TEA) and cocadimethylamine (CDMA) at different concentration were studied using foam-processing parameters. The properties such as density, water absorption, compression strength and dimensional stability have also been measured. There are other many systems of polyurethanes like elastomers adhesives etc. which can be prepared from natural resources based, which are easily available in our country. Tue, 25 Feb 2014 00:00:00 GMT http://hdl.handle.net/1/94 2014-02-25T00:00:00Z http://hdl.handle.net/1/93 Title: Preparation and Deposition of Hydroxyapatite on Biomaterials by Sol-Gel Technique-A Review Authors: kaur, Sarbjit; Bala, Niraj; Khosla, Charu Abstract: Hydroxyapatite Ca10(PO4)6 (OH)2(HAP) is an important inorganic biomaterial which has attracted the attention of researchers in recent years. Due to its chemical and structural similarity with the mineral phase of bone and teeth, it is widely used for hard tissues repair. Amongst various methods, sol–gel technique has achieved more popularity recently due to synthesis of ceramics powders. The sol–gel process is easily applicable to surface coating as it allows the preparation of high-quality HA thin ilms on metal substrates. It has been observed from the studies that the protective atmosphere during sintering process accomplished after sol-gel coating produces good uniformity of coating material which signiicantly leads to a reduction in the porosity of the coating ilm. In another study it was revealed that mechanical properties of commercial HAP can be signiicantly improved by adding P2O5and Na2CO3 without altering its biocompatibility. It has been found from the extensive literature review that homogeneous and crack-free coatings were obtained on biocompatible substrate implant at higher sintering temperatures. The particle size of the HAP powder increases with the increase of the sintering time and sintering temperature. In this paper a review of the studies done for the preparation and deposition of HAP powder with the sol-gel technique has been detailed. Tue, 25 Feb 2014 00:00:00 GMT http://hdl.handle.net/1/93 2014-02-25T00:00:00Z http://hdl.handle.net/1/92 Title: Potassium as a Marker in Air Particulate Matter After Crop Residue Burning Events in Patiala, India Authors: Singh, Nirankar; Mittal, Susheel; Singh, Rishipal; Agarwal, Ravinder; Awasthi, Amit; Gupta, Prabhat K Abstract: Variations in the concentration levels of suspended particulate matter (SPM) and the particulate associated potassium (K) levels were studied in ambient air of Patiala during 2006-2007 at selected urban and rural locations. Samples of SPM were collected and analyzed for the K concentration using lame photometry. The monthly average of SPM levels ranged between 100±30-446±94 µgm-3 at the urban site and 111±22-491±173 µgm-3 at the rural site. An increase in SPM levels was observed during the crop residue burning (CRB) periods at the rural as well as urban area site. At the urban area site, monthly average K concentration varied between 3.3±0.58 µgm -3 to 12.74±4.82 µgm-3 while levels varied between 3.42±1.33 µgm -3 to 31.81±14.19 µgm-3 at the rural site. Peak K concentration (31.81±14.19 µgm ) was obtained at rural area site during October 2007. The study revealed that the concentration of K and SPM was signiicantly higher at rural area site as compared to the urban area site during CRB months. Tue, 25 Feb 2014 00:00:00 GMT http://hdl.handle.net/1/92 2014-02-25T00:00:00Z http://hdl.handle.net/1/91 Title: Synthesis and Characterization of Cobalt Nitrate Hexahydrat Co(No3)2.6H2O Doped Polyaniline Composite Authors: Kumari, Kiran; Ali, Vazid; Gupta, Rajesh; Lakshmi, G.B.V.S.; Zulfequar, M. Abstract: Polyaniline is synthesized via chemical oxidation polymerization and then doped by chemically with Cobalt nitrate hexahydrate Co(No3)2.6H2O at different concentrations such as 4, 8, 12, 16, 20 and 30 % (w/w). The effect of dopant in polyaniline is studied by UV-Visible spectroscopy, XRD, Fourier transform infrared (FTIR), SEM and I-V characteristics method. It has been found from UV-Visible study that optical parameters changed as absorption coeficient (α) and extinction coeficient (k) show signiicant changes after doping. Both direct and indirect band gaps are appeared in the doped samples, which decrease with increase in doping. DC conductivity is studied at temperature 298.15 K. DC conductivity increases with the increase in concentration of dopant. It has been also observed from FTIR study that there are structural changes in polyaniline on the addition of dopant and signiicant observations noticed: when polyaniline doped at 30 % dopant concentration. Tue, 25 Feb 2014 00:00:00 GMT http://hdl.handle.net/1/91 2014-02-25T00:00:00Z