No abstract

An elevator rope for high-rise building is forcibly excited by the displacement of the building caused by earthquakes and wind forces. In high-rise building, the elevator rope may resonate with the natural frequency of the building; hence, effective solution to reduce the rope displacement is demanded. In this paper, a method to suppress the transverse vibration of elevator rope using vertical vibration of counterweight is proposed. Rope lateral vibration is controlled by fluctuating rope tension using up-and-down motion of this counterweight. Finite difference analyses of rope vibration with counterweight are performed to verify the validity of this method. Experiments involving forced vibration of a rope whose length is constant are performed. In the experiments, guide bar is used to suppress the rotation motion of the rope. As a result, rope sway is reduced to about 1/2, when the cage is stopped. The optimal natural frequency of vertical vibration of counterweight is about 2 times of the natural frequency of the rope lateral vibration.

No prospective, randomized study has been conducted to date in Japan comparing the use of warfarin and rivaroxaban for preventing thrombotic and bleeding events in the perioperative period of catheter ablation CA for atrial brillation AF. This was a prospective, open-label randomized study assessing the safety and ef cacy of warfarin and rivaroxaban in the perioperative period of CA for AF. Thrombotic events including silent cerebral lesion SCL detected by magnetic resonance imaging MRI , bleeding events, and coagulation test results were assessed in correlation with interrupted warfarin or rivaroxaban in the perioperative period of CA for AF. Finally, thirty-six patients 18 men ; aged 65 9.4 years who underwent CA for AF were prospectively enrolled. No instance of symptomatic cerebral infarction occurred, but 12 of 36 patients 33.3 showed new SCLs during the postprocedural cerebral MRI examination 8/21 in the rivaroxaban group and 4/15 in the warfarin group ; P 0.47. The duration of hospitalization was signi cantly shorter in the rivaroxaban group than in the warfarin group 6 vs. 8 days ; P 0.0135. The incidence of minor bleeding was signicantly lower in the rivaroxaban group than in the warfarin group 0 vs. 26.6 ; P 0.078. D-dimer concentration was signi cantly higher in the SCL group than in the no-SCL group P 0.024 under warfarin, while the values of protein S P 0.017 and prothrombin time P 0.018 were signi cantly lower in the SCL group than in the no-SCL group under rivaroxaban. Rivaroxaban usage in CA is safer than warfarin usage with respect to the incidence of minor bleeding. In patients receiving rivaroxaban therapy, a lower protein S level may be correlated with the incidence of SCL in CA.