The filling construction of permeable geosynthetic tubes is considered.First,an analytical approach is developed to determine the internal pressure,tension and shape of the cross section of a geosynthetic tube based o...The filling construction of permeable geosynthetic tubes is considered.First,an analytical approach is developed to determine the internal pressure,tension and shape of the cross section of a geosynthetic tube based on its volume.An analytical solution for the drainage rate of the tube is then derived.The course of the filling construction is divided into several time intervals and the volume of the tube after each interval is obtained from the equilibrium of flow calculated from the drainage rate and filling rate.The validity of our analytical approach is tested by comparing our results with previously published experimental result.The results of this comparison indicate that our method is applicable for simulating the filling construction of permeable geosynthetic tubes.展开更多
AIM: To investigate whether illness severity has an impact on gastric residual volume (GRV) in medical critically ill patients. METHODS: Medical intensive care unit (ICU) patients requiring nasogastric feeding were en...AIM: To investigate whether illness severity has an impact on gastric residual volume (GRV) in medical critically ill patients. METHODS: Medical intensive care unit (ICU) patients requiring nasogastric feeding were enrolled. Sequential Organ Failure Assessment (SOFA) score was assessed immediately preceding the start of the study. Acute Physiology and Chronic Health Evaluation (APACHE) Ⅱ scores were recorded on the first, fourth, seventh, and fourteenth day of the study period. GRV was measured every 4 h during enteral feeding. The relationship be-tween mean daily GRV and SOFA scores and the correlation between mean daily GRV and mean APACHE Ⅱ score of all patients were evaluated and compared. RESULTS: Of the 61 patients, 43 patients were survivors and 18 patients were non-survivors. The mean daily GRV increased as SOFA scores increased (P < 0.001, analysis of variance). Mean APACHE Ⅱ scores of all patients correlated with mean daily GRV (P = 0.011, Pearson correlation) during the study period. Patients with decreasing GRV in the first 2 d had better survival than patients without decreasing GRV (P = 0.017, log rank test). CONCLUSION: GRV is higher in more severely ill medical ICU patients. Patients with decreasing GRV had lower ICU mortality than patients without decreasing GRV.展开更多
The vent tube is commonly used for the water hammer protection in the hydropower tailrace system. In transient processes, with air entering and exiting the vent tube, one sees complex hydraulic phenomena, which threat...The vent tube is commonly used for the water hammer protection in the hydropower tailrace system. In transient processes, with air entering and exiting the vent tube, one sees complex hydraulic phenomena, which threaten the station＇s safe operation. It is necessary to investigate the transient mechanisms in the tailrace system with vent tube. In this paper, a 3-D, two-phase numerical model of a vent tube on the connection of the tailrace tunnel and the diversion tunnel, is developed based on the FLUENT with the volume of fluid（VOF） algorithm to investigate the transient air-water flow patterns and the complex hydraulic phenomena in the vent tube of the tailrace system. A 1-D and 3-D unidirectional adjacent coupling（1-D-3-D-UAC） approach with a linear interpolation method is adopted to adjust the timesteps between the 1-D model and the 3-D model on the tunnel inlet and outlet boundaries through the user defined function（UDF）, to transmit the data from the 1-D model to the 3-D model. The model is verified by comparing the results obtained by using the 1-D model alone and from the experiments in literature. The transient flow processes under the full load rejection consist of four stages： the water level dropping stage, the air entering stage, the air pocket collapsing stage, and the air exiting stage. Detailed hydraulic phenomena in the air pocket collapsing process are also discussed.展开更多
基金Project (No. KYJD09036) supported by the Fundamental Research Funds for the Central Universities,China
文摘The filling construction of permeable geosynthetic tubes is considered.First,an analytical approach is developed to determine the internal pressure,tension and shape of the cross section of a geosynthetic tube based on its volume.An analytical solution for the drainage rate of the tube is then derived.The course of the filling construction is divided into several time intervals and the volume of the tube after each interval is obtained from the equilibrium of flow calculated from the drainage rate and filling rate.The validity of our analytical approach is tested by comparing our results with previously published experimental result.The results of this comparison indicate that our method is applicable for simulating the filling construction of permeable geosynthetic tubes.
基金Supported by Kaohsiung Veterans General Hospital, Grant No.VGHKS 94-082
文摘AIM: To investigate whether illness severity has an impact on gastric residual volume (GRV) in medical critically ill patients. METHODS: Medical intensive care unit (ICU) patients requiring nasogastric feeding were enrolled. Sequential Organ Failure Assessment (SOFA) score was assessed immediately preceding the start of the study. Acute Physiology and Chronic Health Evaluation (APACHE) Ⅱ scores were recorded on the first, fourth, seventh, and fourteenth day of the study period. GRV was measured every 4 h during enteral feeding. The relationship be-tween mean daily GRV and SOFA scores and the correlation between mean daily GRV and mean APACHE Ⅱ score of all patients were evaluated and compared. RESULTS: Of the 61 patients, 43 patients were survivors and 18 patients were non-survivors. The mean daily GRV increased as SOFA scores increased (P < 0.001, analysis of variance). Mean APACHE Ⅱ scores of all patients correlated with mean daily GRV (P = 0.011, Pearson correlation) during the study period. Patients with decreasing GRV in the first 2 d had better survival than patients without decreasing GRV (P = 0.017, log rank test). CONCLUSION: GRV is higher in more severely ill medical ICU patients. Patients with decreasing GRV had lower ICU mortality than patients without decreasing GRV.
基金Project supported by the National Key R&D Program of China(Grant No.2016YFC0401810)the Research Project of Science and Technology Commission of Shanghai Munici-pality(Grant No.16DZ1202205)and the Fundamental Research Funds for the Central Universities(Grant No.2016B10814)
文摘The vent tube is commonly used for the water hammer protection in the hydropower tailrace system. In transient processes, with air entering and exiting the vent tube, one sees complex hydraulic phenomena, which threaten the station＇s safe operation. It is necessary to investigate the transient mechanisms in the tailrace system with vent tube. In this paper, a 3-D, two-phase numerical model of a vent tube on the connection of the tailrace tunnel and the diversion tunnel, is developed based on the FLUENT with the volume of fluid（VOF） algorithm to investigate the transient air-water flow patterns and the complex hydraulic phenomena in the vent tube of the tailrace system. A 1-D and 3-D unidirectional adjacent coupling（1-D-3-D-UAC） approach with a linear interpolation method is adopted to adjust the timesteps between the 1-D model and the 3-D model on the tunnel inlet and outlet boundaries through the user defined function（UDF）, to transmit the data from the 1-D model to the 3-D model. The model is verified by comparing the results obtained by using the 1-D model alone and from the experiments in literature. The transient flow processes under the full load rejection consist of four stages： the water level dropping stage, the air entering stage, the air pocket collapsing stage, and the air exiting stage. Detailed hydraulic phenomena in the air pocket collapsing process are also discussed.
