Assessing the performance of intumescent coatings using bench‐scaled cone calorimeter and finite difference simulations

A method was developed to assess the heat insulation performance of intumescent coatings. The method consists of temperature measurements using the bench‐scaled experimental set‐up of a cone calorimeter and finite difference simulation to calculate the effective thermal conductivity dependent on time/temperature. This simulation procedure was also adapted to the small scale test furnace, in which the standard time–temperature curve is applied to a larger sample and thus which provides results relevant for approval. Investigations on temperature and calculated effective thermal conduction were performed on intumescent coatings in both experimental set‐ups using various coating thicknesses. The results correspond to each other as well as showing the limits of transferability between both fire tests. It is shown that bench‐scaled cone calorimeter tests are a valuable tool for assessing and predicting the performance of intumescent coatings in larger tests relevant for approval. The correlation fails for processes at surface temperatures above 750°C, which are not reached in the cone calorimeter, but are attained in the small scale furnace set‐up. Copyright © 2006 John Wiley & Sons, Ltd.     

Relative Protein Efficiency Ratios for Wheat-Based Breakfast Cereals

Male weanling rats were subjected to standard 28-day PER trials following the outline by the AOAC (1984) except that the diets contained 8.5% protein (N × 6.25) as one of six wheat-based breakfast cereals, white flour, whole wheat flour or casein. One of the cereals was an extrusion puffed product, three were flaked and toasted cereals and two were extruded cereals. Of the two extruded cereals, one was lightly toasted and the other was more heavily toasted. Relative PER (R-PER) was lowest for the puffed cereal (- 15.3) and highest for the extruded-lightly toasted cereal (69.9). R-PER for the flaked cereals ranged from 1.7 to 16.3; the other extruded cereal had a R-PER of 2.8 and each of the two flours had a R-PER of 42.9.     

Orientation in uniaxially stretched plasticized atactic polystyrene

Summary Fourier transform infrared spectroscopy and birefringence measurements have been used to study the changes in molecular orientation which occur on drawing of plasticized as compared to pure polystyrene (PS) at a temperature T=Tg+Cte. No influence of plasticizers on orientation can be detected whatever the interactions between small molecules and PS chains are. Comparison with previous results obtained on PS-poly(vinylmethyl ether) compatible blends confirms the importance of the macromolecular nature of the second component to enhance the friction coefficient leading to higher level of chain orientation.     

High-speed, polyimide-based semi-insulating planar buried heterostructures

We describe planar buried heterostructure lasers which have low capacitance (lpF), large bandwidth (19GHz), high power (>20mW/facet) and high temperature operation (100°C). These lasers are very suitable for long-distance, highspeed digital and analogue signal transmission.