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81.
V.M. Bhatnagar J.C. David J.M. Vergnaud O. Riveros-Ravelo H. Dieu 《Journal of Analytical and Applied Pyrolysis》1984,6(1):81-93
The pyrolysis of a clear fire-retardant coating was studied by using several analytical techniques, such as flash pyrolysis, thermogravimetry (TGA) and differential scanning calorimetry (DSC). The gaseous products were identified using gas chromatography-mass spectrometry (GC-MS). The coating consisted of a polyurethane film with or without chlorinated alkanes, which, when exposed to a flame, produced intumescence. The main ingredients of the coating were tenth-second butyrate and hexamethylene diisocyanate (Desmodur N) for polytrethane and Chlorowax 70 as the fire-retarding component. Pyrolysis was carried out in an inert medium. The pyrograms for polyurethane, Chlarowax and Chlorowax-polyurethane mixtures were obtained at 400, 600 and 800dgC. Some principal gaseous products resulting from the pyrolysis were identified by GC-MS. Other experiments were conducted using DSC under argon, and TGA with temperature programming. The pyrolysis began at 260°C for the Chlorowax-polyurethane system and at higher temperatures for polyurethane. Pyrolysis was also conducted using TGA under isothermal conditions and at selected temperatures. 相似文献
82.
A rapid and accurate electrometric method for the determination of potassium ferricyanide solutions has been investigated. It consists in titrating ferricyanide solutions potentiometrically against standard AgNO3, using a silver indicator electrode in conjunction with a saturated calomel electrode connected by a KNO3 bridge. Either of the reagents may be used as the titrant. A marked change in e.m.f is observed at thc end-point corresponding to the formation and precipitation of Ag3[Fe(CN)6]. The curves have a regular form, a pronounced maximum in dE/dV occurs at the end-point and the results are very accurate and reproducible. The reaction, though simple, affords a quantitative method for the determination of ferricyanide or silver. The effect of neutral salts and ethanol on the accuracy of the end-point has been studied. 相似文献
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85.
The Ramanujan Journal - We develop a calculus that gives an elementary approach to enumerate partition-like objects using an infinite number-theoretic matrix. We call this matrix the... 相似文献
86.
Shaheen Sultana Sushma Talegaonkar Gaurav Mittal Aseem Bhatnagar Farhan J. Ahmad 《Chromatographia》2010,72(3-4):321-326
Spectrophotometric and LC methods have been developed and validated for the analysis of alendronate sodium in tablet dosage forms. Methods were based on reaction of the primary amino group of alendronate with ninhydrin reagent in methanolic solution of sodium bicarbonate. The condensed product exhibited UV absorption maximum at 569 nm whereas neither the reagents nor the analyte had any UV absorption. A Box-Behnken statistical design was employed to study the effect of independent variables, ninhydrin (X 1 ), NaHCO3 (X 2 ) and drug concentration (X 3 ) on dependent variable, absorption via spectrophotometer. From the point prediction tool of design software, it was observed that ninhydrin (0.26%) and NaHCO3 (0.048 mol L?1) produced maximum absorption. These optimized parameters were then selected for method validation. The methods obeyed Beer’s law over a selected concentration range with good correlation co-efficient (>0.99). The limit of detection and limit of quantification were 4.5 and 13.75 μg mL?1 by spectroscopy, and 87 and 263 ng mL?1 by LC, respectively. Accuracy, precision and % recovery were satisfactory for the proposed method. The method was highly feasible and reproducible for determination of alendronate sodium in bulk powder and pharmaceutical dosage form. 相似文献
87.
Patel Akash Pravinkumar Bhatnagar Divyang kumar Rajendran Senthil Prabhu Sethuramalingam 《Journal of Thermal Analysis and Calorimetry》2022,147(1):675-684
Journal of Thermal Analysis and Calorimetry - Due to the low performance observed during natural convection with fluids such as air and water, nanofluid research was carried out to analyse them for... 相似文献
88.
An environment friendly method for the synthesis of 2-oxo/thioxooctahydroquinazolin-5-one derivatives has been devised using Ceric ammonium nitrate (CAN) as catalyst and polyethylene glycol (PEG) as solvent. The cytotoxic effect of these compounds was studied on U87 human glioma cells, compounds 4c, 4d and 4e are found to exhibit excellent activity at a concentration as low as 0.06 μg/ml. 相似文献
89.
Polyethylene glycol (PEG) was found to be an inexpensive non-toxic and effective medium for the one-pot synthesis of N-substituted decahydroacridine-1,8-diones in the presence of ceric ammonium nitrate (CAN) as the catalyst in high yields. Also, the solvent system can be recovered and reused; making this protocol economically and potentially viable. 相似文献
90.
The synthesis of 2,4,6-tris(di-tetrahydrofurfuroxy)phosphinyl-s-triazine (2) was achieved by the reaction of cyanuric chloride with tris(tetrahydrofurfuryl)-phosphite (1) or with sodium bis(tetrahydrofurfuryl)phosphite (5). 2 on treatment with anhydrous ammonia yielded ammonium salt of 2,4-diamino-6-tetrahydro-furfuroxy-phosphinyl-s-striazine (3), which on methylolation yielded (4). The reaction of 2 and 4 with cellulose powder under different experimental
conditions was carried out and they were found to exhibit promising fire-retardant properties. 相似文献