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Thermosiphons are circuits in which a flow pattern is driven by buoyancy forces originated from density differences. These equipments are widely applied in industries due to their simplicity and high heat transfer rate. In this paper, a 40.2-mm-inner-diameter and 1-m-high tubular thermosiphon was evaluated at single-phase and multiphase conditions. The experimental unit was set to represent vapor generator systems employed in most industrial applications as an ASTM A192 tube was used at heating section. For single-phase flow, an experimental database regarding temperature and velocity was obtained by thermocouples and particle image velocimetry (PIV), respectively. Natural circulation effects were captured allowing the observation of a preferred path of the flow at the center of the tube. For multiphase flow, liquid-phase velocity was obtained by PIV technique and vapor-phase velocity, diameter, and void fraction were obtained by phase Doppler anemometry (PDA). Results pointed to the establishment of partial boiling regime as bubble presence decelerated liquid velocity. The present study discussed natural convection regime, transition regime that appeared once boiling initiated, and system behavior when subcooled nucleate boiling was established. This represents a robust database regarding phase change and the instabilities that this phenomenon can cause. [ABSTRACT FROM AUTHOR]

Case Description--6 horses were determined to have torsion of a liver lobe at 4 referral institutions over a 21-year period. Clinical Findings--Clinical findings were nonspecific but often included signs of marked inflammation. Two of the 6 horses were examined because of colic, and 2 were assessed because of peritonitis that failed to respond to treatment; the remaining 2 horses were examined because of nonspecific clinical signs that included inappetence, lethargy, and weight loss. The results of laboratory tests were widely variable, and values for liver en-zyme activities were typically within reference limits or only mildly increased. Most affected horses had markedly increased peritoneal nucleated cell counts. Treatment and Outcome--Exploratory laparotomy and resection of the affected liver lobe was performed in 5 horses. Three of those patients survived to discharge. Clinical Relevance--Results suggested that diagnosis of liver lobe torsion in horses may be difficult because clinical signs and results of laboratory testing are nonspecific and variable. Most affected horses had markedly abnormal peritoneal fluid. The prognosis for hepatic lobe torsion can be good, and early surgical correction is expected to improve outcome. [ABSTRACT FROM AUTHOR]