BACKGROUND Ultrasonic devices are widely used in many surgical fields,including hepatectomy;however,the negative effects of tissue pad degradation of ultrasonic devices,including those in liver surgery,remain unknown....BACKGROUND Ultrasonic devices are widely used in many surgical fields,including hepatectomy;however,the negative effects of tissue pad degradation of ultrasonic devices,including those in liver surgery,remain unknown.The Harmonic®1100(H-1100)scalpel has advanced heat control technology than previous models,such as the Harmonic®HD1000i(H-HD1000i).We hypothesized that,because of its advanced temperature-control technology,the H-1100 scalpel would show less tissue pad degradation,resulting in superior sealing performance,compared to that with the H-HD1000i scalpel.AIM To elucidate ultrasonic device tissue pad degradation effects on instrument temperature and sealing performance using ex vivo porcine liver/vessel models.METHODS Two different harmonic scalpels were used and compared:A newer model,the H-1100 scalpel,and an older model,the H-HD1000i scalpel.Using ex vivo porcine livers,each instrument was activated until the liver parenchyma was dissected.The device temperature(passive jaw temperature)was measured after every 10 consecutive activations,until 300 transections of the porcine liver were performed.Tissue pad degradation was evaluated after 300 activations.Sealing performance was evaluated using excised porcine carotid vessels;vessel sealing speed and frequency of vessel burst pressure below 700 mmHg were determined after 300 transections of porcine liver parenchyma.RESULTS The temperature of the H-HD1000i scalpel was approximately 10℃higher than that of the H-1100 scalpel,and gradually increased as the number of activations increased.The median passive jaw temperature of the H-HD1000i scalpel was significantly higher than that of the H-1100 scalpel(73.4℃vs 65.1℃;P<0.001).After 300 transections of porcine liver parenchyma,less tissue pad degradation was observed with the H-1100 scalpel than with the H-HD1000i scalpel(0.08 mm vs 0.51 mm).The H-1100 scalpel demonstrated faster vessel-sealing speed(4.9 sec.vs 5.1 sec.)and less frequent vessel burst pressure<700 mmHg(0%vs 40%)after 300 activations than the H-HD1000i scalpel;however,the difference did not reach statistical significance(P=0.21 and P=0.09,respectively).CONCLUSION In an ex vivo porcine hepatectomy model,the H-1100 scalpel shows lower passive jaw temperature and maintains its sealing performance by avoiding tissue pad degradation compared to that with the H-HD1000i.展开更多
Non-contacting finger seals represent an advanced non-contacting and compliant seal in gas turbine sealing technology.This paper proposes a new structure of noncontacting finger seals with double interlocking pads.The...Non-contacting finger seals represent an advanced non-contacting and compliant seal in gas turbine sealing technology.This paper proposes a new structure of noncontacting finger seals with double interlocking pads.The numerical analysis model based on the thermo-fluid-structure coupling method for the new type finger seal was established.The influence of working conditions on leakage of the seal was studied and compared with the single padded non-contacting finger seal.The results show that the interface between the bottom of the finger pad and rotor surface is the main leakage path that forms the gas film with obvious variations of pressure and flow velocity.Under high temperature and high pressure operating conditions,the hydrodynamic effect of the gas film is enhanced,and lifting force is significantly improved.The deformation of fingers is composed of elastic deformation and thermal deformation.At room temperature,the deformation of fingers is mainly elastic deformation and points to the center of the rotor,which reduces the gas film clearance.The deformation of fingers at high temperature and high pressure creates a circumferentially convergent gap between the bottom of the pad and the rotor,which is beneficial to improve the loading capacity and to reduce leakage of the seal.Compared with the typical single padded noncontacting finger seal,the double interlocking padded finger seal proposed in this paper reduces the leakage factor by about 37%,which provides an advanced seal concept with the potential to improve sealing performance under high temperature and high pressure working conditions.展开更多
文摘BACKGROUND Ultrasonic devices are widely used in many surgical fields,including hepatectomy;however,the negative effects of tissue pad degradation of ultrasonic devices,including those in liver surgery,remain unknown.The Harmonic®1100(H-1100)scalpel has advanced heat control technology than previous models,such as the Harmonic®HD1000i(H-HD1000i).We hypothesized that,because of its advanced temperature-control technology,the H-1100 scalpel would show less tissue pad degradation,resulting in superior sealing performance,compared to that with the H-HD1000i scalpel.AIM To elucidate ultrasonic device tissue pad degradation effects on instrument temperature and sealing performance using ex vivo porcine liver/vessel models.METHODS Two different harmonic scalpels were used and compared:A newer model,the H-1100 scalpel,and an older model,the H-HD1000i scalpel.Using ex vivo porcine livers,each instrument was activated until the liver parenchyma was dissected.The device temperature(passive jaw temperature)was measured after every 10 consecutive activations,until 300 transections of the porcine liver were performed.Tissue pad degradation was evaluated after 300 activations.Sealing performance was evaluated using excised porcine carotid vessels;vessel sealing speed and frequency of vessel burst pressure below 700 mmHg were determined after 300 transections of porcine liver parenchyma.RESULTS The temperature of the H-HD1000i scalpel was approximately 10℃higher than that of the H-1100 scalpel,and gradually increased as the number of activations increased.The median passive jaw temperature of the H-HD1000i scalpel was significantly higher than that of the H-1100 scalpel(73.4℃vs 65.1℃;P<0.001).After 300 transections of porcine liver parenchyma,less tissue pad degradation was observed with the H-1100 scalpel than with the H-HD1000i scalpel(0.08 mm vs 0.51 mm).The H-1100 scalpel demonstrated faster vessel-sealing speed(4.9 sec.vs 5.1 sec.)and less frequent vessel burst pressure<700 mmHg(0%vs 40%)after 300 activations than the H-HD1000i scalpel;however,the difference did not reach statistical significance(P=0.21 and P=0.09,respectively).CONCLUSION In an ex vivo porcine hepatectomy model,the H-1100 scalpel shows lower passive jaw temperature and maintains its sealing performance by avoiding tissue pad degradation compared to that with the H-HD1000i.
文摘Non-contacting finger seals represent an advanced non-contacting and compliant seal in gas turbine sealing technology.This paper proposes a new structure of noncontacting finger seals with double interlocking pads.The numerical analysis model based on the thermo-fluid-structure coupling method for the new type finger seal was established.The influence of working conditions on leakage of the seal was studied and compared with the single padded non-contacting finger seal.The results show that the interface between the bottom of the finger pad and rotor surface is the main leakage path that forms the gas film with obvious variations of pressure and flow velocity.Under high temperature and high pressure operating conditions,the hydrodynamic effect of the gas film is enhanced,and lifting force is significantly improved.The deformation of fingers is composed of elastic deformation and thermal deformation.At room temperature,the deformation of fingers is mainly elastic deformation and points to the center of the rotor,which reduces the gas film clearance.The deformation of fingers at high temperature and high pressure creates a circumferentially convergent gap between the bottom of the pad and the rotor,which is beneficial to improve the loading capacity and to reduce leakage of the seal.Compared with the typical single padded noncontacting finger seal,the double interlocking padded finger seal proposed in this paper reduces the leakage factor by about 37%,which provides an advanced seal concept with the potential to improve sealing performance under high temperature and high pressure working conditions.
