Development of dewatering textile materials incorporating slit-pore geometries.

The use of engineering textile materials has emerged as a viable alternative to conventional methods of sludge dewatering in numerous application areas including municipal wastewater, mining, and pulp and paper. Previous studies have focused on the development of empirical ratios between dewatering performance and the porous properties of the textile material, the challenge is that the latter is difficult to characterize using currently available techniques. In this study, a series of dewatering filters were produced using advanced microfabrication techniques to create well-defined slit-pore geometries; a full-factorial design-of-experiments was employed to evaluate the effects of slit-pore dimensions and slit-pore spacing on the cake layer development and overall dewatering performance in constant-rate dewatering tests with municipal digestate that had been pre-treated with a commercial polymer flocculant.

Emulsion/Surface Interactions from Quiescent Quartz Crystal Microbalance Measurements with an Inverted Sensor.

Interactions of three oil-in-water emulsion types with polystyrene-coated quartz crystal microbalance (QCM) sensor surfaces were probed with the QCM cell in both the conventional orientation (i.e., polystyrene surface on the bottom, "looking up") and the inverted orientation (polystyrene on top interior surface of sensor chamber, "looking down").

Weak gelation of hydrophobic guar by albumin in simulated human tear solutions.

This initial study shows that hydrophobic modification of guar polymers used in eye drops forms weak gels with human serum albumin (HSA), suggesting that modified guar may offer advantages for treatment of dry eye diseases that lead to elevated HSA concentrations in tears. Specifically, hydroxypropyl guar samples were oxidized and derivatized with linear alkyl amines to give a series of modified guar polymers (MGuar) bearing hydroxypropyl, N-alkylamide, and carboxyl moieties. MGuar interactions with lysozyme and HSA were measured by binding and rheological methods as functions of the alkyl chain length and the extent of hydrophobic modification.

On formulating ophthalmic emulsions.

The formulation of dilute, transparent ophthalmic emulsions (eye drops) with long shelf lives is a challenge because of the tendency of the emulsion droplets to aggregate, particularly in the presence of the water-soluble polymers typically used in eye drops. While many functions of eye drops, such as lubricity and residence time in the eye, are promoted by high concentrations of high molecular weight water-soluble polymers, emulsified lipids and drugs aggregate in the eye drop bottle if the polymer concentration is above the critical flocculation concentration (CFC). The purpose is to develop a simple approach to predict the CFC for polymers based on information readily available in the literature.