Microstructure and properties of silicon alloyed compacted graphite irons (CGI)

The microstructure, tensile properties and hardness of 25 mm thick compacted graphite iron samples alloyed with 3,01, 3,22, 3,61, 3,97 and 4,29 wt. % Si were analyzed in this paper. It was found that Si promotes and strengthens ferrite. Metallic matrix of compacted graphite iron sample alloyed with 3,01 wt. % Si consisted of 98,1 % ferrite and 1,9 % pearlite. Fully ferritic metallic matrix was obtained in compacted graphite iron samples alloyed with 3,22, 3,61, 3,97 and 4,29 wt. % Si. Nodularity varied from 8 to 13 %. Yield strength increased from 246 to 447 N/mm2, tensile strength increased from 318 to 496 N/mm2, hardness increased from 160 to 227 HBW, and elongation decreased from 3,6 to 1,6 % with an increase in Si content from 3,01 to 4,29 wt. %. Analyzed Si alloyed compacted graphite iron samples have a very uniform hardness and higher ratio Rp02/Rp02 than conventional ferritic, ferritic-pearlitic and pearlitic compacted graphite iron grades

Structuring white rice with gellan gum reduces the glycemic response in healthy humans

White rice has a high glycemic index and its consumption has been linked to an increased risk of developing type-2 diabetes mellitus, increased diabetes associated complications and obesity. In recent in vitro studies we have shown that addition of food hydrocolloids, such as low acyl gellan gum (LAGG), when cooking white rice potentially modifies starch digestion kinetics. The impact in vivo remains to be investigated. We aimed to determine the effect of adding LAGG to white rice on postprandial glycemic, gastrointestinal and appetitive responses in humans. Following LAGG in vitro characterisation, 12 healthy adults participated in a randomised, controlled, crossover study. They consumed isoenergetic meals of jasmine white rice (232 kcal) cooked with (Rice + LAGG) and without (Rice control) 3% w/dry rice w LAGG. Blood glucose, intragastric meal appearance, meal volume and appetite were assessed serially for 2 hours. The incremental area under the curve over two hours (iAUC2h) for blood glucose for the Rice + LAGG meal (93±16 mmol/L·min) was significantly lower than that for the Rice control meal (160±18 mmol/L·min), P = 0.0007. Blood glucose rose postprandially to a peak at T=30 minutes, with the Rice control meal peak (7.3 ± 0.2 mmol/L) significantly higher than that for the Rice + LAGG meal (6.5 ± 0.2 mmol/L), P < 0.01. MRI images showed that for Rice + LAGG there were multiple rice boluses persisting intragastrically throughout the digestion time. There were no significant differences in appetite between meals. The addition of LAGG to the cooking process was effective in reducing postprandial blood glucose responses in healthy humans. If confirmed, this could potentially provide a simple and relatively inexpensive intervention to reduce the post prandial glycemic response to white rice

"Race" and biomedical research: An educational perspective

4 page(s

The properties of silicon alloyed ferritic ductile irons

In this paper the influence of silicon content of 3,1 to 5,4 wt. % on the tensile properties, hardness and impact energy of ferritic ductile iron was analysed. It was found that silicon strengthens the ferrite, resulting in an increase in yield strength and tensile strength with increasing silicon content up to 4,22 wt. %. Elongation and impact energy decreases and the hardness increases with increasing silicon content. Since ferritic ductile irons alloyed and strengthened by silicon have a higher Rp_0,2/R_m ratio and a higher elongation than conventional ferritic, ferritic/pearlitic and pearlitic ductile irons at the same level of tensile strength, we can expect an increased demand for these materials in applications where high resistance to impact load and low temperature impact properties are not required

Philosophy of medicine - Darwinian medicine - an evolutionary perspective on health and disease

3 page(s