Comparing the Mucoadhesivity and Drug Release Mechanisms of Various Polymer-Containing Propranolol Buccal Tablets

The aims were to compare the mucoadhesivity, controlled release properties, and release mechanisms of several polymeric systems of propranolol buccal tablets and to propose polymer(s) for formulation optimization. Mucoadhesivity differences in the polymer ranking between compacts and tablets were found. Mathematical models that best described the matrices were power law or a combination of the power law and Hopfenberg models. Poly acrylic acid (PAA), carboxymethyl cellulose (CMC), and poly ethylene glycol (PEG) in combination, were identified as suitable polymers for formulation optimization of a multipolymeric propranolol buccal tablet. Artificial neural networks were employed as a confirmatory approach to explicate that the selected polymers, in particular PAA, produced the most significant effect on the mean dissolution time and mucoadhesivity.     

Rheological characterization of long fiber thermoplastics – Effect of temperature,fiber length and weight fraction

Isothermal squeeze flow tests were conducted on E-Glass/polypropylene long fiber thermoplastics (LFT) to obtain the rheological characteristics of the material over a range of squeeze rates (0.5–60 mm/min). A transversely isotropic power-law model has been incorporated to capture the combined effect of shear and extensional flow behavior. Scott’s approach [Bird RB. Useful non-Newtonian models; 1976. p. 13–34] was used to obtain the shear power-law parameters, which were then used to calculate the radial velocity in the r-direction. The continuity equation was used to calculate transverse velocity in the z-direction. Radial and through the thickness velocity profiles were determined to obtain the extensional and the shear strain rates. Finally the extensional and shear viscosities were determined at strain rates calculated. Good agreement between the experimental applied stress and the predicted curves from the model was achieved. Effects of mold separation, mold temperature, and fiber length on viscosity at constant fiber weight fraction were examined. Effect of fiber weight fraction on viscosity at constant fiber length, mold separation and temperature was examined. Results indicate that viscosities decrease with either increase in mold temperature or decrease in fiber length at constant mold separation and fiber weight fraction. Viscosities also decreased with decrease in fiber weight fraction.     

Control characteristics and speed controller design for a highperformance permanent magnet synchronous motor drive

The theory of vector control is applied to the nonlinear model of a permanent magnet synchronous motor to develop a linear model for controller design purposes. The operation and relevant mathematics of a pseudo-derivative feedback controller are presented. Controller designs for three different speeds are then considered, and a comparative evaluation is made on the basis of their large and small-signal behavior. In order to test the large-signal response, the detailed nonlinear model of the machine and a real-time model of the inverter switches are used. Results indicate that a critically damped design done so as to ensure that all control and power signals never saturate gives an extremely poor result. Much better small and large-signal responses are achieved by avoiding this constraint and using Zener diodes instead to limit the commanded input into the inverter. Two designs using this technique are presented, an underdamped design with low speed overshoot and an overdamped design with no speed overshoot. The response of the underdamped design was much quicker than that of the overdamped. However the overdamped design has application when speed overshoot is intolerable     

A computer program to predict the performance of slip energyrecovery induction motor drives

Details are provided, in the form of a flowchart, to permit the reconstruction of a computer program to predict the transient and steady-state performance of slip energy recovery induction motor (IM) drives. Slip energy recovery IM drives are different from most other drives in that the inverter is generally connected only after the machine has reached a predetermined speed. The initial conditions of the inverter are therefore nonzero and difficult to obtain. Three techniques that can be used to calculate the initial conditions are discussed. Theoretical predictions are supported by practical results     

Mega-events as a Response to Poverty Reduction: The 2010 FIFA World Cup and its Urban Development Implications

This paper reflects on the trajectory that urban development associated with the 2010 Fédération Internationale de Football Association (FIFA) World Cup has taken in South Africa. The argument suggests that a unique moment has been lost regarding the ability of the World Cup to serve as a catalyst for urban development. This notion is supported by a digest of the international literature which takes a cautious stance in its assessment of the benefits of mega-events. Hence, this paper posits that it is unlikely that poverty alleviation, as a result of fast-tracking South Africa’s urban development impetus, will constitute a significant outcome of the World Cup. Rather, development benefits in cities are likely to be fairly circumscribed. Legacy, the paper argues, should therefore advance beyond an exclusively pro-poor language. In this regard, vigorous public debate is required to arrive at a national consensus of what kind of legacy the 2010 FIFA World Cup is realistically able to achieve.

Layer-by-layer self-assembled nanostructured phthalocyaninatoiron(II)/SWCNT-poly(m-aminobenzenesulfonic acid) hybrid system on gold surface: Electron transfer dynamics and amplification of H2O2 response

The fabrication of nanostructured platform of poly(m-aminobenzenesulfonic acid) functionalised single-walled carbon nanotubes (SWCNTs-PABS)-iron(II)phthalocyanine nanoparticles (nanoFePc) using layer-by-layer(LBL) self-assembly strategy is described. The substrate build-up, via strong electrostatic interaction, was monitored using atomic force microscopy (AFM) and electrochemical measurements. As the number of bilayers is increased, the electron transfer kinetics of the ferricyaninde/ferrocyanide redox probe is decreased, while the electrochemical reduction of H₂O₂ at a constant concentration is amplified. The amplification of the electrochemical response to H₂O₂ detection suggests that this type of electrode could provide an important nano-architectural sensing platform for the development of a sensor.