OPTICAL ASSESSMENT OF CORN OIL DETERIORATION DURING FRYING

The ultraviolet (UV), visible and near-infrared (NIR) absorption changes in corn oil were measured during processes simulating deep fat frying. Corn oil, maintained at 185C, was exposed to various treatments with nitrogen, air, water injection, air with water injection, and steam. Autoxidation due to a combination of air and high temperature in the simulated frying trials caused visible absorption changes between 400 and 580 nm as the oil deteriorated similar to those observed in potato frying experiments. These absorption changes were found to be associated with changes in an ultraviolet absorption band with a maximum near 270 nm. Second-derivative calibration equations developed at various visible and NIR absorption wavelengths successfully predicted the percentage of total polar materials (%TPM) which accumulated in the corn oil during simulated trials of autoxidation (R values from 0.93 to 0.98). Using spectral data from repetitive potato frying experiments, the predicted %TPM calculated with these equations correlated well with kinematic viscosity measurements (R values from 086 to 0.97).     

Calcium Segregation to a Magnesium Oxide (100) Surface

The segregation of calcium to a (100) cleavage surface of an MgO crystal, with bulk calcium concentration of 200 ppm was measured in situ at T =900° to 1450°C in ultrahigh vacuum, using Auger and low-energy ion-scattering spectroscopies. A measured heat of segregation of approximately -50.3 kJ/mol (-12 kcal/mol) is in favorable agreement with a value of -58.7 kJ/mol (-14 kcal/mol) determined using solute strain energy and surface free energy criteria. The equilibrium value for the calcium segregation between 950° and 1000°C is estimated to correspond to a 20% occupation of the surface cation sites.     

Effects of Oxygen Partial Pressure on the Oxidation of Silicon Carbide

The rate of oxidation of silicon carbide was studied at different partial pressures of oxygen. The diffusion rate constant was found to vary with the logarithm of the partial pressure of oxygen according to the theory of oxidation of thin films as proposed by Engell and Hauffe. An alternative explanation based on the change of free energy with surface coverage was also found to fit the data.     

Stress Relief Mechanisms in Magnesia- and Yttria-Stabilized Zirconia

Stabilized zirconias exhibit pronounced photoelastic effects when viewed with transmitted polarized light. Thin sections reveal stress concentrations around pores and inclusions and at grain boundaries. The yield point of these materials, at some high temperature, is exceeded and plastic deformation tends to relieve these stress concentrations. The microhardness measurements of magnesia-stabilized zirconia indicate both solution hardening and solute segregation and help to explain the physical behavior of this system as the amount of MgO is varied.     

Energy Consumption in Water Blanching

The energy consumption of a tubular water blancher and a water blancher with screw conveyor were measured as a basis for suggesting energy conserving modifications. The former required 0.54 MJ/kg and the latter 0.91 MJ/kg, indicating the importance of complete steam condensation. A pilot scale experiment with a water blancher heated with heat exchange and by steam injection confirmed the energy savings potential of heating with an exchanger to minimize escape of steam rather than by steam injection.     

Stress Measurement in Circular Cylinders

A general procedure is presented whereby all the internal stresses in a glass cylinder can be calculated from birefringence observations. The method applies to circular cylinders, either rods or tubes, where the stress distribution may be any arbitrary function of the radial coordinate and where the observation path is far enough from the ends of the cylinder so that end effects are negligible. The method is applied to an oil-tempered solid glass rod and the calculated stress is compared with that expected from a constant cooling rate.     

EFFECT OF LANE-CLOSURE SIGNALS UPON DRIVER DECISION MAKING AND TRAFFIC FLOW.

APPLIED A DECISION-THEORETIC MODEL TO DRIVER BEHAVIOR ON AN URBAN EXPRESSWAY. THE MODEL PERMITS INFERENTIAL MEASUREMENT OF RESPONSIVENESS VS. CONFUSION AND RISK TAKING PREDISPOSITION. THESE VARIABLES AND 2 DIRECT MEASURES (RISK TAKING AND HAZARD) WERE MEASURED IN A FIELD STUDY OF FORCED MERGING FROM A BLOCKED LANE. RESULTANT INDEXES WERE COMPARED UNDER 2 EXPERIMENTALLY MANIPULATED METHODS OF LANE CLOSURE: SIGNAL CLOSURE (SC) AND CONVENTIONAL CLOSURE (CC). THE SC METHOD, WHICH PROVIDES EARLIER WARNING OF THE CLOSURE, WAS SUPERIOR TO CC IN TERMS OF LOWER HAZARD AND GREATER RESPONSIVENESS VS. CONFUSION. THERE WERE ALSO IMPROVEMENTS IN SEVERAL TRAFFIC FLOW CHARACTERISTICS. (PsycINFO Database Record (c) 2010 APA, all rights reserved)