An improved mathematical model to describe the decarburization process in basic oxygen furnaces for steelmaking is presented in this work. This model takes into account those factors or parameters that determine the b...An improved mathematical model to describe the decarburization process in basic oxygen furnaces for steelmaking is presented in this work. This model takes into account those factors or parameters that determine the bath-oxygen impact area, such as the cavity depth, the lance height, the number of nozzles and the nozzles diameter. In the thermal issue, the model includes the targeted carbon content and temperature. The model is numerically solved, and is validated using reported data plant. The oxygen flow rate and the lance height are varied in the numerical simulations to study their effect on the carbon content and decarburization rate.展开更多
Background: Oxygen is a commonly used drug in modern medical care. It has biochemical actions, safe dosage ranges, adverse physiologic effects and can be toxic at high doses and prolonged use. As a drug, it needs a fo...Background: Oxygen is a commonly used drug in modern medical care. It has biochemical actions, safe dosage ranges, adverse physiologic effects and can be toxic at high doses and prolonged use. As a drug, it needs a formal prescription prior to administration. The prescription needs to meet certain basic minimums for appropriateness and safety. Objectives: The aim of the study was to assess the standards of prescriptions for oxygen therapy amongst admitted medical patients at the Dr. George Mukhari Academic Hospital. Materials and Methods: It was a cross-sectional study of 159 acutely ill medical admissions who received supplemental oxygen. The medication charts of patients on oxygen were audited;with regards to the availability and/or adequacy of the prescription for oxygen. Results: Of the one hundred and fifty nine patients on oxygen only 43 (27%) had an actual prescription for oxygen written. The target oxygen saturation was specified in 19 (44%) cases. The device for oxygen delivery was specified in 21 (49%) patients and just over half of the patients (56%) had flow rates indicated on their charts. Conclusion: The practice of oxygen administration in our medical wards was sub-optimal. The audit highlights the need for education and training in acute oxygen therapy.展开更多
Thirty patients in coma state underwent dynamic SPECT with 133Xe, a validated technique for the quantitation of CBF by SPECT, using a new brain dedicated tomograph: CERTO-96. CMRO2 was computed by multiplying the mean...Thirty patients in coma state underwent dynamic SPECT with 133Xe, a validated technique for the quantitation of CBF by SPECT, using a new brain dedicated tomograph: CERTO-96. CMRO2 was computed by multiplying the mean CBF by AVDO2 according to the Fick’s principle. The mean values of CBF, AVDO2 and CMRO2 in patients with good outcome were significantly different from those with worse outcome. On the basis of the best "discriminant threshold", CBF and AVDO2 demonstrated an intermediate accuracy in separating the two groups, while CMRO2 showed a satisfactory accuracy.展开更多
文摘An improved mathematical model to describe the decarburization process in basic oxygen furnaces for steelmaking is presented in this work. This model takes into account those factors or parameters that determine the bath-oxygen impact area, such as the cavity depth, the lance height, the number of nozzles and the nozzles diameter. In the thermal issue, the model includes the targeted carbon content and temperature. The model is numerically solved, and is validated using reported data plant. The oxygen flow rate and the lance height are varied in the numerical simulations to study their effect on the carbon content and decarburization rate.
文摘Background: Oxygen is a commonly used drug in modern medical care. It has biochemical actions, safe dosage ranges, adverse physiologic effects and can be toxic at high doses and prolonged use. As a drug, it needs a formal prescription prior to administration. The prescription needs to meet certain basic minimums for appropriateness and safety. Objectives: The aim of the study was to assess the standards of prescriptions for oxygen therapy amongst admitted medical patients at the Dr. George Mukhari Academic Hospital. Materials and Methods: It was a cross-sectional study of 159 acutely ill medical admissions who received supplemental oxygen. The medication charts of patients on oxygen were audited;with regards to the availability and/or adequacy of the prescription for oxygen. Results: Of the one hundred and fifty nine patients on oxygen only 43 (27%) had an actual prescription for oxygen written. The target oxygen saturation was specified in 19 (44%) cases. The device for oxygen delivery was specified in 21 (49%) patients and just over half of the patients (56%) had flow rates indicated on their charts. Conclusion: The practice of oxygen administration in our medical wards was sub-optimal. The audit highlights the need for education and training in acute oxygen therapy.
文摘Thirty patients in coma state underwent dynamic SPECT with 133Xe, a validated technique for the quantitation of CBF by SPECT, using a new brain dedicated tomograph: CERTO-96. CMRO2 was computed by multiplying the mean CBF by AVDO2 according to the Fick’s principle. The mean values of CBF, AVDO2 and CMRO2 in patients with good outcome were significantly different from those with worse outcome. On the basis of the best "discriminant threshold", CBF and AVDO2 demonstrated an intermediate accuracy in separating the two groups, while CMRO2 showed a satisfactory accuracy.
