Liver resections are demanding operations which can have life threatening complications although they are performed by experienced liver surgeons. Recently new technologies are applied in the field of liver surgery, h...Liver resections are demanding operations which can have life threatening complications although they are performed by experienced liver surgeons. Recently new technologies are applied in the field of liver surgery, having one goal: safer and easier liver operations. The aim of this article is to address the issue of bloodless liver resection using radiofrequency energy. Radionics, Cool-tipTM System and Tissue Link are some of the devices which are using radiofrequency energy. All information included in this article, refers to these devices in which we have personal experience in our unit of liver surgery. These devices take advantage of its unique combination of radiofrequency current and internal electrode cooling to perform sealing of the small vessels and biliary radicals. Dissection is also feasible with the cool-tip probe. For the purposes of this study patient sex, age, type of disease and type of surgical procedure in association with the duration of parenchymal transection, blood loss, length of hospital stay, morbidity and mortality were analyzed. Cool-tip RF device may provide a unique, simple and rather safe method of bloodless liver resections if used properly. It is indicated mostly in cirrhotic patients with challenging hepatectomies (segment Ⅷ, central resections). The total operative time is eliminated and the average blood loss is significantly decreased. It is important to note that this technique should not be applied near the hilum or the vena cava to avoid damage of these structures.展开更多
Transcritical film cooling was investigated by numerical study in a methane cooled methane/oxygen rocket engine.The respective time-averaged Navier-Stokes equations have been solved for the compressible steady three-d...Transcritical film cooling was investigated by numerical study in a methane cooled methane/oxygen rocket engine.The respective time-averaged Navier-Stokes equations have been solved for the compressible steady three-dimensional(3-D) flow.The flow field computations were performed using the semi-implicit method for pressure linked equation(SIMPLE) algorithm on several blocks of nonuniform collocated grid.The calculation was conducted over a pressure range of 202 650.0 Pa to 1.2×107 Pa and a temperature range of 120.0 K to 3 568.0 K.Twenty-nine different cases were simulated to calculate the impact of different factors.The results show that mass flow rate,length,diameter,number and diffused or convergence of film jet channel,injection angle and jet array arrangements have great impact on transcritical film cooling effectiveness.Furthermore,shape of the jet holes and jet and crossflow turbulence also affect the wall temperature distribution.Two rows of film arranged in different axial angles and staggered arrangement were proposed as new liquid film arrangement.Different radial angles have impact on the film cooling effectiveness in two row-jets cooled cases.The case of in-line and staggered arrangement are almost the same in the region before the second row of jets,but a staggered arrangement has a higher film cooling effectiveness from the second row of jets.展开更多
文摘Liver resections are demanding operations which can have life threatening complications although they are performed by experienced liver surgeons. Recently new technologies are applied in the field of liver surgery, having one goal: safer and easier liver operations. The aim of this article is to address the issue of bloodless liver resection using radiofrequency energy. Radionics, Cool-tipTM System and Tissue Link are some of the devices which are using radiofrequency energy. All information included in this article, refers to these devices in which we have personal experience in our unit of liver surgery. These devices take advantage of its unique combination of radiofrequency current and internal electrode cooling to perform sealing of the small vessels and biliary radicals. Dissection is also feasible with the cool-tip probe. For the purposes of this study patient sex, age, type of disease and type of surgical procedure in association with the duration of parenchymal transection, blood loss, length of hospital stay, morbidity and mortality were analyzed. Cool-tip RF device may provide a unique, simple and rather safe method of bloodless liver resections if used properly. It is indicated mostly in cirrhotic patients with challenging hepatectomies (segment Ⅷ, central resections). The total operative time is eliminated and the average blood loss is significantly decreased. It is important to note that this technique should not be applied near the hilum or the vena cava to avoid damage of these structures.
文摘Transcritical film cooling was investigated by numerical study in a methane cooled methane/oxygen rocket engine.The respective time-averaged Navier-Stokes equations have been solved for the compressible steady three-dimensional(3-D) flow.The flow field computations were performed using the semi-implicit method for pressure linked equation(SIMPLE) algorithm on several blocks of nonuniform collocated grid.The calculation was conducted over a pressure range of 202 650.0 Pa to 1.2×107 Pa and a temperature range of 120.0 K to 3 568.0 K.Twenty-nine different cases were simulated to calculate the impact of different factors.The results show that mass flow rate,length,diameter,number and diffused or convergence of film jet channel,injection angle and jet array arrangements have great impact on transcritical film cooling effectiveness.Furthermore,shape of the jet holes and jet and crossflow turbulence also affect the wall temperature distribution.Two rows of film arranged in different axial angles and staggered arrangement were proposed as new liquid film arrangement.Different radial angles have impact on the film cooling effectiveness in two row-jets cooled cases.The case of in-line and staggered arrangement are almost the same in the region before the second row of jets,but a staggered arrangement has a higher film cooling effectiveness from the second row of jets.
