Modeling of Hydrogen Jet Diffusion Flames (On the Direct Influence of Molecular Viscoty

It was believed that the increase of molecular viscosity due to high temperature raises the dissipation rate of turbulence in low-turbulent regions in a combustion field. Hence, the objective of the present study was to verify this both experimentally and theoretically. Experiments were carried out on jet diffusion flames of hydrogen, and then, a numerical simulation was conducted for the experimental results. In the simulation, the κ-ε two-equation model was used as a turbulence model and a new source term was added to the κ-equation to represent the dissipation rate of turbulence kinetic energy due to molecular viscosity. The calculated results agree well with the experimental ones. It was found that the new source term suppresses turbulence in low turbulent regions situated around the nozzle exit and the periphery of jets, and changes the condition in the whole combustion field greatly. The present work suggested that consideration of the viscous effect is important in the modeling of turbulent combustion fields.・rights：日本機械学会・rights：本文データは学協会の許諾に基づきCiNiiから複製したものである・relation：isVersionOf：http://ci.nii.ac.jp/naid/110002494156

The Local Reaction Rate in Round-Jet Diffusion Flames

A combustion model for turbulent diffusion flames is estimated frequently through the comparison of the simulated result with the experimental one. Usually, profiles of time-averaged concentration and temperature are used in that comparison, because the local reaction rate cannot be directly measured. However, since their profiles are also influenced largely by transport phenomena, it is difficult to estimate the combustion model properly with this method. Therefore, it is desirable to calculate the local reaction rate from experimental results and compare it with the simulated one. In the present study, from this point of view, the local reaction rate was tried to obtain by numerical calculation using measured values for a hydrogen jet diffusion flame. Then, it was suggested through the comparison of the obtained result with the simulated one that the method proposed here can provide reliable values for the local reaction rate.・rights：日本機械学会・rights：本文データは学協会の許諾に基づきCiNiiから複製したものである・relation：isVersionOf：http://ci.nii.ac.jp/naid/110002981414

Two-stage hepatectomy aiming for the development of intrahepatic venous collaterals for multiple colorectal liver metastases

Abstract Background Aggressive hepatectomy with venous resection has a higher risk of postoperative liver failure (POLF) than hepatectomy without venous reconstruction; however, venous reconstruction is technically demanding. We performed a novel two-stage hepatectomy (TSH) without venous reconstruction in a patient with bilobar multiple colorectal liver metastases located near the caval confluence, waiting for the development of intrahepatic venous collaterals between procedures. Case presentation A 60-year-old man was referred to our hospital with sigmoid colon cancer accompanied by intraabdominal abscess and two synchronous liver metastases. One of the liver tumors (tumor 1) was located in segment 8 near the caval confluence and was attached to both the right hepatic vein (RHV) and middle hepatic vein (MHV). The other tumor (tumor 2) in the left lobe invaded the umbilical portion of the portal vein. Both liver metastases decreased in size after four cycles of panitumumab/5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX) therapy. Radical liver resection was planned because tumor 1 had not invaded the MHV. However, three-dimensional volumetric software showed that the non-congested volume of the future liver remnant was estimated at 354 ml, which corresponded to 26.3% of the total liver volume. TSH was scheduled to avoid POLF. We first performed limited resection of segment 8 with resection of the RHV root. After the first hepatectomy, the development of intrahepatic venous collaterals between the RHV and MHV was seen on computed tomography and magnetic resonance imaging. The estimated non-congested future liver remnant was 1242 ml, 78.5% of the total liver volume. Therefore, the patient underwent left hemihepatectomy 58 days after the first hepatectomy. We saw no adhesions around the porta hepatis, and the left hepatic artery and left branch of the portal vein were safely exposed and divided. Intraoperative Doppler ultrasonography revealed intrahepatic venous collaterals arising from RHV to MHV. The patient’s postoperative course was uneventful, and he underwent eight cycles of panitumumab/FOLFOX therapy for 5 months after the second hepatectomy. Conclusions Our TSH strategy helped avoid POLF by waiting for the development of intrahepatic venous collaterals