SUMMARYDirect methanol fuel cells have the potential to power future microelectronic and portable electronic devices because of their high energy density. One of the major obstacles that currently prevent the widespread applications of direct methanol fuel cells is the methanol crossover through the polymer-electrolyte membrane. Methanol crossover is closely related to several factors including membrane structure and morphology, membrane thickness, and fuel cell operating conditions such as temperature, pressure, and methanol feed concentration. This work presents a comprehensive overview of the state-ofthe-art technology for the most important factors, affecting methanol crossover in direct methanol fuel cells. In addition, the current and future directions of the research and development activities, aiming to reduce the methanol crossover are reviewed and discussed in order to improve the performance of direct methanol fuel cells.

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The current study was designed to develop a topical gel formulation for improved skin penetration of lornoxicam (LOR) for enhancement of its analgesic activity. Moreover, the effect of different penetration enhancers on LOR was studied. The LOR gel formulations were prepared by using hydroxylpropyl methylcellulose (HPMC) and carbopol. The carbopol gels in presence of propylene glycol (PG) and ethanol were developed. The formulated gels were characterized for pH, viscosity, and LOR release using Franz diffusion cells. Also, in vitro skin permeation of LOR was conducted. The effect of hydroxypropyl β-cyclodextrin (HP β-CD), beta-cyclodextrin (β-CD), Tween 80, and oleic acid on LOR permeation was evaluated. The optimized LOR gel formulation (LORF8) showed the highest flux (14.31 μg/cm2/h) with ER of 18.34 when compared to LORF3. Incorporation of PG and HP β-CD in gel formulation (LORF8) enhanced the permeation of LOR significantly. It was observed that LORF3 and LORF8 show similar analgesic activity compared to marketed LOR injection (Xefo). This work shows that LOR can be formulated into carbopol gel in presence of PG and HP β-CD and may be promising in enhancing permeation.

A mathematical model for the evaporation of micro- and nano-sized solution droplets is developed. This model is used to predict whether the particles produced by spray drying and pyrolysis are fully filled or hollow. The model includes the non-continuum effects on the droplet evaporation. This is achieved by combining an interpolation formula based on the numerical solution of the Boltzmann equation for the transition regime with the continuum based governing equations. Results show that the non-continuum effects can be significant for the evaporation of submicron and nano-sized droplets in atmospheric pressures. Correlations for the final particle size and its wall thickness in terms of reactor temperature and pressure and the initial solution concentration are developed. The predictions are in good agreement with experiments performed on the submicron zirconia particles, prepared by spray pyrolysis.