In a case of cephalothoracopagus, the umbilical artery (UA) was observed with color Doppler method, and the findings were compared with the hemodynamics of 46 normal fetuses. The patient was a 25-year-old primigravida who had appeared for routine prenatal visits since her 6th week of pregnancy. At a later time, the patient was examined after an interval of 4 weeks. Although an ultrasonography was also conducted, unfortunately, any findings of cephalothoracopagus were not detected. In the 25th week of gestation, we hospitalized her for marked polyhydramnios (amniotic fluid index: 280 mm), at which time an ultrasound examination revealed cephalothoracopagus. In the UA, the Vmax was 30.3 cm/s (normal fetus at 25–28 weeks: 33.5 ± 3.9 cm/s). The UA hemodynamics fell below the normal range. At 26 weeks, the UA Vmax was 56.5 cm/sec, a level which significantly exceeded the normal range. The patient underwent a cesarean section at 27 weeks of gestation; the indication was fetal distress. This is caused by the condition in which the fetal heart beats decreases to 90 beats per minute 3 times during a 10-min period as measured on the cardiotocograms. She delivered a 1,392-gram female with an Apgar score of 2 points (respiratory 1 point and heart rate 1 point). The infant was a cephalothoracopagus, with one head, two hearts, four upper limbs, and four lower limbs. The neonate died from circulatory failure 56 min after birth.
The ladle treatment of liquid steel is mainly responsible for the steel cleanliness, since it generates as well as eliminates most of the oxide inclusions. Today, the combination of computational fluid dynamics and population balance modeling makes the numerical simulation of this complex three‐phase reactor possible. First, the comprehensive three‐dimensional turbulent multiphase flow model is developed to study the behavior of argon bubbles in liquid steel based on the geometry and operating conditions corresponding to the real industrial process. This simulation is validated by comparing the calculated mixing time with the experimental value predicted from ladle sampling. Then, the balanced equation for a population of oxide inclusions with aggregation mechanism is coupled with the hydrodynamic modeling. To obtain the solution of this equation two approaches are used: the classes method (CM) and the quadrature method of moments (QMOM). The simulation results show the equivalence of these methods and their respective advantages are presented.
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