Recently we showed how crystallization in microemulsions could lead directly to the most stable polymorph, thereby leapfrogging Ostwald’s rule of stages. Here we consider in more details the crystallization of mefenamic acid from dimethylformamide microemulsions. Crystallization of mefenamic acid from bulk DMF has previously been shown to produce only the metastable Form II irrespective of the ...

effluent from ro (reverse osmosis) systems during recovery gradually becomes concentrated and supersaturated with soluble salts such as calcium carbonate (caco3), calcium sulfate (caso4), barium sulfate (baso4) and silica (sio2). thus we were looking for procedures to prevent precipitation of soluble salts on the membrane surface and decrease membrane permeability. therefore, recovery could be ...

in this investigation we synthesized nax-nanozeolite by hydrothermal crystallization conditions.these nanoparticles were prepared at different conditions in a temperature controlled shaker. thesynthesized zeolites were characterized by instrumental analysis methods, such as x-raydiffraction (xrd), x-ray fluorescence (xrf), scanning electron microscopy (sem) andtransmission electron microscopy (...

We examine the crystallization dynamics of nanoparticles reversibly tethered by DNA hybridization. We show that the crystallization happens readily only in a narrow temperature ‘‘slot’’, and always proceeds via a two-step process, mediated by a highly-connected amorphous intermediate. For lower temperature quenches, the dynamics of unzipping strands in the amorphous state is sufficiently slow t...

Protein crystallization is a major bottleneck in determining tertiary protein structures from genomic sequence data. This paper describes a microfluidic system for screening hundreds of protein crystallization conditions using less than 4 nL of protein solution for each crystallization droplet. The droplets are formed by mixing protein, precipitant, and additive stock solutions in variable rati...

The amorphous-to-microcrystalline phase transition of Ge in Pb/Ge multilayer geometry has been investigated as a function of layer thicknesses with the use of high-temperature x-raydiA'raction techniques. During crystallization, the modulation structure is destroyed and the Pb texture improves. In addition, the crystallization temperature decreases with decreasing amorphous Ge thickness and inc...

Dielectric spectra of the polyester poly(propylene succinate) were measured upon crystallization. For this model aliphatic polyester the alpha and beta relaxations appear simultaneously and are well resolved in the experimental frequency window. During isothermal crystallization, this fact allows one to use the beta relaxation to characterize the crystalline structural development while the alp...

We report that an electron beam focused for high resolution imaging rapidly initiates observable crystallization of amorphous Me-Si-C films. For 200-keV electron irradiation of Nb-Si-C and Zr-Si-C films, crystallization is observed at doses of ~2.8*10 and ~4.7*10 e /nm, respectively. The crystallization process is driven by atomic displacement events, rather than heating from the electron beam ...

The kinetics of the initial stage of crystallization of one-component gas hydrates in aqueous solutions are analyzed. The temporal evolution of the volume of hydrate crystallized and the moles of gas consumed are determined. Expressions are derived for the supersaturation dependence of the hydrate crystallite growth rate and the induction time in hydrate crystallization. These expressions are u...

Amorphous films of the anticonvulsant drug carbamazepine are easily accessible by various methods, while the crystallization into specific polymorphs represents a challenging and time-consuming task. In this work, the crystallization of drop cast carbamazepine at silica surfaces is investigated by atomic force microscopy and both in situ and ex situ grazing incidence X-ray diffraction. The pris...