Optimisation of an in-process lineal dielectric sensor for liquid moulding of carbon fibre composites

A dielectric sensor appropriate for process monitoring of carbon fibre composites manufacturing has been optimised and implemented in Resin Transfer Moulding (RTM). The sensor comprises a pair of twisted insulated copper wires and can be adapted to monitor both flow and cure. To simulate the dielectric response of the sensor, an electric field model was developed. The model was coupled with a multi-objective optimisation genetic algorithm to optimise the sensor design. The optimisation showed that increasing wire radius and decreasing coating thickness increases sensor sensitivity. Different sensor designs were implemented and used in a series of RTM trials to validate the technology in industrial conditions. The sensor operated successfully at pressures up to 7 bar and temperatures up to 180°C. A low diameter sensor using copper wire coated with polyimide showed the best response monitoring flow with an accuracy of 95%, whilst also following the cure and identifying vitrificatio

Maternal-neonatal erythrocyte membrane Na+, K+ -ATPase and Mg2+-ATPase activities in relation to the mode of delivery

Free radical production and high catecholamine levels are implicated in the modulation of Na+, K+-ATPase, and Mg2+-ATPase activities. The aim of this study was to investigate the effect of the mode of delivery on the above-mentioned enzyme activities in maternal - neonatal erythrocyte membrane. Women with normal pregnancy (N = 30) were divided into two groups: Group A (N = 16) with normal labor and vaginal delivery, and Group B (N = 14) with scheduled cesarean section; 20 non-pregnant women were the controls. Blood was obtained from controls and mothers, pre- versus post-delivery, and from the umbilical cord (CB). Total antioxidant status (TAS), membrane enzyme activities, and catecholamine blood levels were measured with a commercial kit, spectrophotometrically, and by HPLC methods, respectively. The results showed that: TAS levels, catecholamine, and the membrane enzyme activities were similar in the two groups of mothers pre-delivery, whereas both enzyme activities were lower than those of controls. TAS levels were reduced whereas Na+, K+ -ATPase activities (0.35 ± 0.03 vs. 0.65 ± 0.06 μmol Pi/h × mg protein, P < 0.001), and catecholamine levels were increased post-delivery in mothers of Group A and unaltered in Group B (0.38 ± 0.02 vs. 0.40 ± 0.03 μmol Pi/h × mg protein, P > 0.05), at the same times of study. Mg2+ -ATPase activities remained unaltered in both groups of mothers and newborns. Na+, K+-ATPase activity was similarly lower in the CB of neonates than those of their mothers, pre-delivery. Our results suggest that: (a) during a normal vaginal delivery process, the low TAS and the increased levels of catecholamines may increase Na+, K+-ATPase activity, post-delivery; (b) the low enzyme activities evaluated in mothers pre-delivery may be due to the high estrogen levels and those in newborns due to perinatal immaturity. © Springer-Verlag 2008

The effect of the mode of delivery on the maternal-neonatal erythrocyte membrane acetylcholinesterase activity

Free radical production and high catecholamine levels are implicated with the modulation of acetylcholinesterase (AChE) activity. Objective: To investigate the effect of the mode of delivery on maternal-neonatal erythrocyte membrane AChE activity. Subjects and methods: Some women with normal pregnancy (N = 30) were divided into two groups: group A (N = 16) with normal labour and vaginal delivery and group B (N = 14) with scheduled Cesarean section, twenty non-pregnant women were the controls. Blood was obtained from controls and from mothers pre- vs post-delivery as well as from the umbilical cord (CB). Total antioxidant status (TAS), membrane AChE activities and catecholamine blood levels were measured with a commercial kit, spectrophotometrically and HPLC methods, respectively. Results: TAS and catecholamine levels as well as membrane AChE activities were similar in the two groups of mothers pre-delivery and in controls. TAS levels were reduced whereas AChE activities and catecholamine levels were increased post-delivery in mothers of group A and unaltered in group B at the same times of study. AChE activity was similarly lower in the CB of neonates than those of their mothers pre-delivery. Conclusions: During a normal delivery process, the low TAS, the increased levels of catecholamines and the increased AChE activity, post-delivery, may be due to the increased stress due to the participation of uterus and skeletal muscles as during endurance exercise. The low AChE activity in newborns may be related to perinatal immaturity. © 2008 The Canadian Society of Clinical Chemists