Eddy Current Thickness Measurement of the Zink Layer on Galvanized Steel Wires

By resolving Maxwell’s Equations for the case of a long coil encircling a galvanized wire (fig.l), we can calculate the normalized impedance diagram. Later, during the experiments, we will directly use this diagram to find the thickness of the zinc layer. Before resolving Maxwell’s Equations, a few words about the normalized impedance diagram in general. Figure 2 shows the normalized impedance diagram for the simple case of a long coil encircling a wire made out of a homogeneous conductive material of permeability µr and with a fill factor equal to one. A fill factor, η=a2/c2 (fig. 3), equal to one, means that there is no air between the coil and the wire. The x axis represents the normalized resistance (1) (Rp−Re)/ωLe, where Rp is the real component of the impedance Zp of the coil when there is a part inside the coil, Re and ωLe are respectively the real and the imaginary components of Ze when the coil is empty

Consequences of cervical pessary for subsequent pregnancy : follow-up of randomized clinical trial (ProTWIN)

Funding Information: B.W.M. is supported by a NHMRC Investigator grant (GNT1176437). B.W.M. reports consultancy for ObsEva and has received research funding from Guerbet, Ferring and Merck. The original ProTWIN trial was funded by ZonMW grant 200310004. We did not receive any funding for this follow‐up research.Peer reviewedPublisher PD

Eddy Current Thickness Measurement of the Zink Layer on Galvanized Steel Wires

By resolving Maxwell’s Equations for the case of a long coil encircling a galvanized wire (fig.l), we can calculate the normalized impedance diagram. Later, during the experiments, we will directly use this diagram to find the thickness of the zinc layer. Before resolving Maxwell’s Equations, a few words about the normalized impedance diagram in general. Figure 2 shows the normalized impedance diagram for the simple case of a long coil encircling a wire made out of a homogeneous conductive material of permeability µr and with a fill factor equal to one. A fill factor, η=a2/c2 (fig. 3), equal to one, means that there is no air between the coil and the wire. The x axis represents the normalized resistance (1) (Rp−Re)/ωLe, where Rp is the real component of the impedance Zp of the coil when there is a part inside the coil, Re and ωLe are respectively the real and the imaginary components of Ze when the coil is empty.</p

Consequences of cervical pessary for subsequent pregnancy: follow-up of randomized clinical trial (ProTWIN)

Objective: To evaluate the effect of cervical pessary, as a strategy to prevent preterm birth (PTB), on the outcome of subsequent pregnancy and maternal quality of life 4 years after the index twin pregnancy. Methods: Between 2009 and 2012, the ProTWIN trial randomized women with a multiple pregnancy to pessary use vs standard care for the prevention of PTB. The trial showed no benefit in unselected women with a twin pregnancy, but showed a 60% reduction in poor perinatal outcomes in favor of the pessary group in the subgroup of women with a mid-trimester short cervix (cervical length < 38 mm). All women were invited to participate in a follow-up study 4 years after their participation in the ProTWIN trial. In this follow-up study, maternal quality of life was assessed using the EQ-5D-3L questionnaire and women were asked separate questions about subsequent pregnancies. Results were compared between women who were randomized to the pessary vs the control group in the ProTWIN trial by calculating relative risk (RR) and 95% CI. Subgroup analysis was performed for women with a mid-trimester short cervix (cervical length < 38 mm). Results: Of the 813 women included in the ProTWIN trial, 408 (50.2%) participated in this follow-up study, comprising 228 randomized to the pessary group and 180 to the control group in the original trial. The median interval between participation in the ProTWIN trial and participation in this follow-up study was 4.1 (interquartile range (IQR), 3.9–7.1) years. Ninety-eight (24.0%) participants tried to conceive after their participation in the ProTWIN trial. Of those, 22 (22.4%) women did not have a subsequent pregnancy (no difference between pessary and control groups), seven (7.1%) women had at least one miscarriage but no live birth, and 67 (68.4%) women had at least one live birth (35 in the pessary vs 32 in the control group; RR, 0.93 (95% CI, 0.8–1.07)). In two women, the pregnancy outcome was unknown. Preterm delivery (< 37 weeks of gestation) of the first live birth occurred in three women in the pessary vs one woman in the control group (all singleton; RR, 2.57 (95% CI, 0.28–23.44)). No differences were found between the pessary and control groups in the subgroup of women with mid-trimester short cervix, but the numbers analyzed were small. The median health state index score was 0.95 (IQR, 0.82–0.95), with no difference between the pessary and control groups. Conclusion: Our findings suggest that there are no long-term effects of pessary use on the outcome of subsequent pregnancies and maternal quality of life. Data on obstetric outcome were limited due to the small numbers