In a continuing study under way at North Carolina State University, a cohort of students took five chemical engineering courses taught by the same instructor in five consecutive semesters. This report examines gender differences in the students' academic performance, persistence in chemical engineering, and attitudes toward their education and themselves. The women in the study on average entered chemical engineering with credentials equal to or better than those of the men, but exhibited an erosion relative to the men in both academic performance and confidence as they progressed through the curriculum. Possible causes of the observed disparities are suggested and remedial measures are proposed.

No abstract

Amorphous Al2O3 thin films were grown on Si(100) and glass substrates by low-pressure metalorganic chemical vapor deposition using aluminum acetylacetonate and water vapor as source materials. Water vapor played an important role in the oxidation process and produced carbon-free, pure Al2O3 films. The deposition temperature could be lowered to 230 °C. The films were characterized by means of x-ray diffraction, x-ray photoelectron spectroscopy, Auger electron spectroscopy, Rutherford backscattering spectrometry, and ellipsometry.

No abstract

An investigation of the mass and heat transfer equations describing radial and axial profiles for tubular reactors in laminar and plug flow is reported. Reactor conditions evaluated were isothermal, constant wall temperature, and adiabatic. Both diffusion and nondiffusion were considered. The reaction investigated was the demethylation of toluene in the presence of hydrogen.It was found that diffusion plays only a minor role in laminar flow for the conditions investigated. It was also found that isothermal and constant wall temperature reactor operation affected the temperature and concentration profiles very little when r / R was less than 0.6.In recent years, considerable research has been carried out in the analyses of tubular reactors considering both the radial velocity and temperature distributions. Much of this work has been applied to first-order reactions in order to simplify the analysis ( 3 , 4, 6, 8 ) ; however, the approach has been extended to photochemical reactions by Schecter*and Wissler (10) and to the treatment of a reversible homogeneous reaction (A 2 B ) by Rothenberg and Smith (9). Few, if any, commercially important reactions have been treated by these techniques. The demethylation of toluene was chosen as an example of a non firstorder reaction of considerable industrial significance. It was desired to calculate concentration and temperature profiles rigorously under several methods of reactor operation: isothermal, constant wall temperature, and adiabatic. It was hoped that these results would suggest the optimum method of reactor operation for this reaction. THEORETICAL DEVELOPMENTThe partial differential equation resulting from an energy balance for tube flow with chemical reaction is as follows:where M is defined by the velocity profile as( 2 ) In an analogous manner, a mass transfer equation is derived in which diffusion is only considered in the radial direction:R" The usual simplifying assumption of plug flow reduces Equations ( 1 ) and (3) torespectively. Equations (1) and ( 3 ) and the simplified Eqwtions ( 4 ) and (5) were solved by finite-difference techniques by using a Burroughs B5500 digital computer. Conversion of the partial differential equations to finite-difference equations was carried out by the method outlined by Jensen and Jeffreys ( 5 ) . Equation (1)