The acidity constants of some synthesized protonated pyrazolo quinazoline compounds were determined potentiometrically at ionic strength of 0.1 M in DMF: water (60:40 v/v) system at different temperatures (298.15 K to 318.15 K). The pKa values have been found to increase with increasing electron-donating nature of substitutions. Some thermodynamics parameters such as enthalpy (ΔH°), Gibb’s free...

Microfluidic devices are a promising new tool for studying and optimizing (bio)chemical reactions and analyses. Many (bio)chemical reactions require accurate temperature control, such as for example thermocycling for PCR. Here, a new integrated temperature control system for microfluidic devices is presented, using chemical and physical processes to locally regulate temperature. In demonstratio...

An efficient reaction cascade delivering a series of pyrrolo[1,2-a]quinolines bearing phosphonate or phosphine oxide moieties is presented. This sequence exploits the in situ transformation of propargylic alcohols into transient allenes by means of a strategic [2,3]-sigmatropic rearrangement followed by trapping of the resulting allenes by an adjacent pyrrole ring. Furthermore, the initial smal...

The paper deals with adaptive control of a continuous stirred tank reactor (CSTR). A nonlinear model of the process is approximated by a continuous-time external linear model. The parameters of the CT external linear model of the process are estimated using a corresponding delta model. The control system with two feedback controllers is considered. The controller design is based on the polynomi...

This work describes an eeort to model the radio-frequency curing of epoxy adhesives in bonding of composites. We present a model based on the three-dimensional heat equation which includes nonlinear heat generating terms. A constructive proof of existence and uniqueness of solutions to our governing equations is given, providing a framework for the development of a computational method. Further...

The paper deals with an application of robust static output feedback control to an exothermic continuous-time stirred tank reactor with parametric uncertainties and multiple steady states. The problem of robust controller design is converted to solution of linear matrix inequalities and a computationally simple non-iterative algorithm is presented. The possibility to use robust static output fe...

The catalytic decomposition process in the initial stage of carbon nanotube ~CNT! growth is investigated for the system of acetylene (C2H2) on the Fe~001! surface through first-principles electronic structure calculation. In its most stable configuration, the C-C bond of C2H2 is lying on the hollow site along the @110# direction of the Fe~001! surface. The formation of the CH fragments accompan...

This work reports the adsorption of strontium from aqueous solutions onto PAN/zeolite composite. The strontium adsorption on the composite adsorbent was studied as a function of initial strontium concentration, pH of the solution, contact time and temperature. Adsorption isotherms like Langmuir, Freundlich, Dubinin-Radushkevich (D-R) and Temkin were used to analyze the equilibrium data at the d...

Assignments based on dynamic simulation of a batch reactor and a semi-batch reactor in which exothermic reactions are conducted, are used to teach students the various aspects of process safety. The students can observe temperature runaway taking place because of incidents, such as overcharging, cooling water failure, pipe blockage and excessive initial heating. They can derive various strategi...

Three water-soluble N-alkyl ammonium resorcinarene chlorides decorated with terminal hydroxyl groups at the lower rims were synthesized and characterized. The receptors were decorated at the upper rim with either terminal hydroxyl, rigid cyclohexyl, or flexible benzyl groups. The binding affinities of these receptors toward three viologen derivatives, two of which possess an acetylmethyl group ...