Structural dynamics of an iron molybdate catalyst under redox cycling conditions studied with in situ multi edge XAS and XRD.

The structural dynamics and phase transformations of an iron molybdate catalyst with excess molybdenum trioxide (Mo/Fe = 2.0) were studied during redox cycling of the catalyst using in situ multi-edge X-ray absorption spectroscopy (XAS) at the Mo K-edge (transmission mode) and Fe K-edge (fluorescence mode) in combination with X-ray diffraction (XRD). X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) analysis showed that heating under reducing conditions with methanol up to 400 °C produced MoO and FeMoO.

Modeling of temperature profiles in an environmental transmission electron microscope using computational fluid dynamics.

The temperature and velocity field, pressure distribution, and the temperature variation across the sample region inside an environmental transmission electron microscope (ETEM) have been modeled by means of computational fluid dynamics (CFD). Heating the sample area by a furnace type TEM holder gives rise to temperature gradients over the sample area. Three major mechanisms have been identified with respect to heat transfer in the sample area: radiation from the grid, conduction in the grid, and conduction in the gas.

Inactivation of a solid-state detergent protease by hydrogen peroxide vapor and humidity.

An experimental study on solid-state stability of a detergent protease (Savinase) is reported. The inactivation kinetics of technical grade enzyme powder was determined as a function of gas phase H(2)O(2) concentration and humidity by employing a quick assay running over few hours instead of several weeks as typical in industry. The results indicated that enzymes adsorbed significant amounts of moisture and H(2)O(2) during exposure.

Process development of continuous glycerolysis in an immobilized enzyme-packed reactor for industrial monoacylglycerol production.

Continuous and easily operated glycerolysis was studied in different lipase-packed columns to evaluate the most potential process set-ups for industrial monoacylglycerol (MAG) production. Practical design-related issues such as enzyme-filling degree, required reaction time, mass transfer investigations, and capacity and stability of the enzyme were evaluated. A commercially available immobilized Candida antarctica lipase B was used to catalyze the glycerolysis reaction between glycerol and sunflower oil dissolved in a binary tert-butanol: tert-pentanol medium.