Laboratory study of three riverbed soil samples denoted as A, B and C have been carried out by determining the soils Porosity, Hydraulic conductivity, Permeability and also investigating if there are points of converg...Laboratory study of three riverbed soil samples denoted as A, B and C have been carried out by determining the soils Porosity, Hydraulic conductivity, Permeability and also investigating if there are points of convergence between the discharge rate and angle of tilt for the above mentioned samples. The experimental results for Porosity were approximately within 34% - 37%, Hydraulic conductivity was within 3.02 × 10-5 - 9.70 × 10-5 (m/s) and Permeability was within 2.74 × 10-12 - 8.80 × 10-12 (m2). Pressure generally increases as distance of flow increases for θ = 5° - 25° but there was decrease in pressure as distance of flow increases for all three samples when θ = 0°. The points of convergence for the discharge rate ranged from 0.001 × 10-10 - 4.54 × 10-10 (m3/s), while the angle of tilt convergence points ranged from 0.1° to 3.6°. There was increase in discharge rate as angle of tilt increases for all three samples.展开更多
Background: The main function of the endotracheal tube (ETT) cuff is to ensure a tight seal between the tracheal wall and the endotracheal tube to prevent stomach contents from entering the trachea during ventilation ...Background: The main function of the endotracheal tube (ETT) cuff is to ensure a tight seal between the tracheal wall and the endotracheal tube to prevent stomach contents from entering the trachea during ventilation thus preventing aspiration. Whereas excessive inflation of the cuff is associated with complications as a result of impaired blood supply to the trachea mucosa, low inflation pressure puts the patient at risk of aspiration. This study sought to find the accuracy of correctly estimating the cuff pressure and whether experience has effect on the accuracy. Methods: After approval from the Ethics Committee, we observed 199 patients who had general anaesthesia and had been intubated at the Komfo Anokye Teaching Hospital,KumasiGhana. Anaesthesia practitioners were blinded to the study. The endotracheal cuff pressure was measured using a low pressure manometer. The experience of the Anaesthetist was also noted. Results: Only 26% of the cuff pressures measured were within the acceptable range of 20-30 cm H2O. 4.5% of the pressures measured were below the acceptable minimum value of20 cm H2O hence exposing the patient to the risk of aspiration. 68% of the cuff pressures measured were above the maximum pressure of30 cm H2O. Physician anaesthetists were likely to inflate the cuff correctly. They had average inflation pressures of24 cm H2O with minimum and maximum inflation pressures of15 cm H2O and32 cm H2O respectively. Resident physician anaesthetists inflate the endotracheal pressures moderately high, an average of41.64 cm H2O. Nurse anaesthetists and student nurse anaesthetists had a tendency to overinflate the endotracheal cuff above the recommended range of 20-30 cm H2O. Their mean inflating pressures were 64.7 and 68.54 respectively. Conclusion: ETT cuff pressures measured by the low pressure aneroid manometer in patients undergoing general anaesthesia in Komfo Anokye Teaching Hospital are routinely high and are significantly higher when inflated by nurse anaesthetists, student nurse anaesthetists and Anaesthesia residents.展开更多
The actuating mechanism of a manometer is to magnify and transform the small displacement generated by elastic components, and then the pressure value is indicated by the deflection angle of the pointer. The error bet...The actuating mechanism of a manometer is to magnify and transform the small displacement generated by elastic components, and then the pressure value is indicated by the deflection angle of the pointer. The error between the indicated and actual pressure value can be large without giving sufficient consideration to the displacement of the elastic component and the inherent non-linearity of a actuating mechanism in its traditional design. In this paper, in order to increase the accuracy and rationality of transmission, the elastic component and transmission non-linearity is fitted and the mathematical models are constructed based on centre displacement of elastic instru- ment components. An optimum program is compiled by MATIABS. O, the optimal parameters to compensate the non- linear displacement of a crank link in two groups to spring is obtained. The error analysis of the manometer shows that it is an efficient method to reduce the errors caused by the elastic components and the non-liner characteristic of actuating a mechanism through the optimized design.展开更多
文摘Laboratory study of three riverbed soil samples denoted as A, B and C have been carried out by determining the soils Porosity, Hydraulic conductivity, Permeability and also investigating if there are points of convergence between the discharge rate and angle of tilt for the above mentioned samples. The experimental results for Porosity were approximately within 34% - 37%, Hydraulic conductivity was within 3.02 × 10-5 - 9.70 × 10-5 (m/s) and Permeability was within 2.74 × 10-12 - 8.80 × 10-12 (m2). Pressure generally increases as distance of flow increases for θ = 5° - 25° but there was decrease in pressure as distance of flow increases for all three samples when θ = 0°. The points of convergence for the discharge rate ranged from 0.001 × 10-10 - 4.54 × 10-10 (m3/s), while the angle of tilt convergence points ranged from 0.1° to 3.6°. There was increase in discharge rate as angle of tilt increases for all three samples.
文摘Background: The main function of the endotracheal tube (ETT) cuff is to ensure a tight seal between the tracheal wall and the endotracheal tube to prevent stomach contents from entering the trachea during ventilation thus preventing aspiration. Whereas excessive inflation of the cuff is associated with complications as a result of impaired blood supply to the trachea mucosa, low inflation pressure puts the patient at risk of aspiration. This study sought to find the accuracy of correctly estimating the cuff pressure and whether experience has effect on the accuracy. Methods: After approval from the Ethics Committee, we observed 199 patients who had general anaesthesia and had been intubated at the Komfo Anokye Teaching Hospital,KumasiGhana. Anaesthesia practitioners were blinded to the study. The endotracheal cuff pressure was measured using a low pressure manometer. The experience of the Anaesthetist was also noted. Results: Only 26% of the cuff pressures measured were within the acceptable range of 20-30 cm H2O. 4.5% of the pressures measured were below the acceptable minimum value of20 cm H2O hence exposing the patient to the risk of aspiration. 68% of the cuff pressures measured were above the maximum pressure of30 cm H2O. Physician anaesthetists were likely to inflate the cuff correctly. They had average inflation pressures of24 cm H2O with minimum and maximum inflation pressures of15 cm H2O and32 cm H2O respectively. Resident physician anaesthetists inflate the endotracheal pressures moderately high, an average of41.64 cm H2O. Nurse anaesthetists and student nurse anaesthetists had a tendency to overinflate the endotracheal cuff above the recommended range of 20-30 cm H2O. Their mean inflating pressures were 64.7 and 68.54 respectively. Conclusion: ETT cuff pressures measured by the low pressure aneroid manometer in patients undergoing general anaesthesia in Komfo Anokye Teaching Hospital are routinely high and are significantly higher when inflated by nurse anaesthetists, student nurse anaesthetists and Anaesthesia residents.
文摘The actuating mechanism of a manometer is to magnify and transform the small displacement generated by elastic components, and then the pressure value is indicated by the deflection angle of the pointer. The error between the indicated and actual pressure value can be large without giving sufficient consideration to the displacement of the elastic component and the inherent non-linearity of a actuating mechanism in its traditional design. In this paper, in order to increase the accuracy and rationality of transmission, the elastic component and transmission non-linearity is fitted and the mathematical models are constructed based on centre displacement of elastic instru- ment components. An optimum program is compiled by MATIABS. O, the optimal parameters to compensate the non- linear displacement of a crank link in two groups to spring is obtained. The error analysis of the manometer shows that it is an efficient method to reduce the errors caused by the elastic components and the non-liner characteristic of actuating a mechanism through the optimized design.
