NOPR Collection:

Candle: A light into the past

Sun, 01 Jul 2001 00:00:00 GMT

Title: Candle: A light into the past Authors: Wisniak, Jaime Abstract: The historical development of the candle is a fascinating subject because it reflects the parallel development of chemical industry, the understanding of physical and chemical phenomena, and the ingenuity of the human being. Today, the burning of a candle is already being studied under microgravity conditions. A semicircular blue flame is found to result under microgravity, in sharp contrast to an oblong two coloured flame observed under gravity of the earth. Page(s): 319-326

Immobilisation of α-L-rhamnosidase of Aspergillus terreus on bagasse particles based matrix

Sun, 01 Jul 2001 00:00:00 GMT

Title: Immobilisation of α-L-rhamnosidase of Aspergillus terreus on bagasse particles based matrix Authors: Yadav, Sarita; Yadav, K D S Abstract: α-L-rhamnosidase from Aspergillus terreus has been immobilised on bagasse particles based matrix. K_m, pH and temperature optima of the immobilized enzyme using narigin as the substrate have been found to be 0.24 mM, 4.0 and 55°C respectively. The corresponding values for the same enzyme in the solution phase are 0.16 mM, 4.0 and 55°C respectively. The immobilized preparation of α-L-rhamnosidase hydrolyses naringin present in Citrus sinansis juice indicating its applicability in the debittering of citrus fruit juices. Page(s): 314-318

A numerical solution to enzyme emulsion liquid membrane reactor model for sequential bienzymatic reaction

Sun, 01 Jul 2001 00:00:00 GMT

Title: A numerical solution to enzyme emulsion liquid membrane reactor model for sequential bienzymatic reaction Authors: Pal, Parimal; Datta, Siddhartha; Bhattacharya, Pinaki Abstract: Dynamic mathematical models of liquid membrane-immobilized multienzyme reaction systems involve a large number of algebraic, ordinary and nonlinear partial differential equations with different types of boundary conditions. Solutions of such model equations are often difficult and stand in the way of realistic modeling efforts in this field. In the present study, attempt has been made to numerically solve such model equations for a liquid membrane-immobilized sequential bienzymatic reaction system through development of a software (MEMBSOL). In the solution process, partial differential equations have been converted into ordinary differential equations by using a finite difference technique in which the spatial derivatives have been discretized while leaving the temporal derivatives unconverted. Through mathematical manipulations, use of fictitious points at the boundaries has been eliminated thereby making the solution-approach a general-purpose one. To integrate the differential equations, Runge-Kutta-Fehlberg method has been applied. An automatic step-size adjustment mechanism has been incorporated in the integration process to produce results with a reasonably desired level of accuracy. In the present computations, numerical solutions with 0.1 percent relative error have been obtained. Page(s): 307-313

Synthesis of polymethylmethacrylate by using triphenybis-muthoniumylide : Kinetics & mechanism

Sun, 01 Jul 2001 00:00:00 GMT

Title: Synthesis of polymethylmethacrylate by using triphenybis-muthoniumylide : Kinetics & mechanism Authors: Bajpai, Radha; Srivastava, A K Abstract: The polymerization of methylmethacrylate initiated by triphenyl- bismuthonium 1,2,3,4-tetraphenylcyclopentadienylide in benzene follows ideal radical kinetics. The activation energy (E_a) and k² _p/k_t values were 76 KJ mol^-1 and 1.06×10^-1 L mol^-1s^-1, respectively. The scanning electron microscopy and qualitative analysis shows that the little amount of bismuth has trapped in polymer matrix. The presence of 6 hyperfine lines in E.S.R. spectrum indicate that the system follows free radical polymerization and the initiation is brought about by phenyl radical. Page(s): 301-306