A study on the effects of the axial gap between stator and rotor upon the stage performance and flow field of a single axial flow turbine stage is presented in this paper. Three axial gaps were tested, which were achieved by moving the stator vane in the axial direction while keeping the disk cavity constant. The effect of the axial gap was investigated at two different conditions, that is design and off-design conditions. The unsteady three-dimensional flow field was analyzed by time-accurate RANS (Reynolds-Averaged Navier-Stokes) simulations. The simulation results were compared with the experiments, in which total pressure and the time-averaged flow field upstream and downstream of the rotor were obtained by five-hole probe measurements. The effect of the axial gap was confirmed in the endwall regions, and obtained relatively at off-design condition. The turbine stage efficiency was improved almost linearly by reducing the axial gap at the off-design condition.

Our new method not only avoids the risk of radiation exposure, but also allows for simple observation of sclerosant range of access, determination of the dosage for each lesion, and accurate administration of therapy to target lesions. This method will contribute to further advances in sclerotherapy, given that it allows administration of sclerosant and visual confirmation of optimal injection dosage, speed, and movement of sclerosant after injection. The authors have indicated no significant interest with commercial supporters.

Hemangioma of the skull is a benign solitary tumor, often found in the frontal or parietal area. A hemangioma lesion typically involves the outer table rather than the inner, but its complete removal at the diploe level is difficult. Full-thickness resection at the calvaria is often needed to ensure a free margin, but it will leave a bony defect that requires reconstruction. Although curettage and covering of the lesion with alloplastic material are a simple treatment option for hemangioma of the skull, it does not always prevent recurrence. Hence, complete resection is needed. As our technical strategies for reconstruction, we organize a split calvarial bone graft if a defect is near the frontal sinus and calcium phosphate cement if it is somewhat far from the sinus.

No abstract

Three patients with moyamoya disease who had undergone bypass surgery at which bilateral encephaloduro-arterio-synangiosis (EDAS) anastomoses were created were studied with three-dimensional spiral CT angiography (3D-CTA). In one patient, magnetic resonance angiography (MRA) clearly visualized the bilateral EDAS, and 3D-CTA also visualized these anastomoses in detail with extreme clarity. In the other two patients, MRA did not clearly demonstrate the right EDAS anastomosis, but 3D-CTA visualized both side surgical collaterals clearly. External carotid angiography confirmed these findings. 3D-CTA might have great value in the evaluation of surgical bypass patency and, in following the disease progression.