The hole reaming and side cutting characteristics of offset one-cone bit and conventional one- cone bit were investigated on simulated drilling experimental equipment. The borehole diameter was a little larger than th...The hole reaming and side cutting characteristics of offset one-cone bit and conventional one- cone bit were investigated on simulated drilling experimental equipment. The borehole diameter was a little larger than the bit diameter due to side force. However, the reaming effect was not very apparent, whether drilling with an offset or conventional one-cone bit. The side cutting displacement increased gradually with increasing depth of drilling and side force. The side cutting displacement of offset onecone bits was larger than that of conventional ones under the same conditions of weight-on-bit （WOB）, rotary speed, side force and borehole depth.展开更多
AIM: To determine which modification to a vascular puncture needle results in increased visualization during ultrasound (US)-guided vascular puncture. METHODS: We evaluated US images of a phantom made of degassed gela...AIM: To determine which modification to a vascular puncture needle results in increased visualization during ultrasound (US)-guided vascular puncture. METHODS: We evaluated US images of a phantom made of degassed gelatin and each of the following four modified versions of a commercially available vascular puncture needle (18 G): re-cut needle, dimple needle, rough-surface needle (rough over the sections of needle located 3-6 mm from the tip), and a needle with four side holes (side holes covered by the sheath). An unmodified commercially available puncture needle was used as a control. Five interventional radiologists evaluated image quality according to the following classification grade:?I, invisible; II, poor; III, moderate; IV, good; V, excellent. RESULTS: The highest score for needle visualization was obtained for the needle with four side holes. The re-cut needle scored the same as the control. Multiple comparisons were conducted using overall evaluation scores among the commercially available needle, dimple needle, rough-surface needle (3-6 mm), and the needle with four side holes. A significantly higher score was obtained for the needle with four side holes (P < 0.05/6). CONCLUSION: The needle with four side holes was prominently visualized and gained a significantly higher score (compared with the other needles) in a phantom evaluation.展开更多
文摘The hole reaming and side cutting characteristics of offset one-cone bit and conventional one- cone bit were investigated on simulated drilling experimental equipment. The borehole diameter was a little larger than the bit diameter due to side force. However, the reaming effect was not very apparent, whether drilling with an offset or conventional one-cone bit. The side cutting displacement increased gradually with increasing depth of drilling and side force. The side cutting displacement of offset onecone bits was larger than that of conventional ones under the same conditions of weight-on-bit （WOB）, rotary speed, side force and borehole depth.
文摘AIM: To determine which modification to a vascular puncture needle results in increased visualization during ultrasound (US)-guided vascular puncture. METHODS: We evaluated US images of a phantom made of degassed gelatin and each of the following four modified versions of a commercially available vascular puncture needle (18 G): re-cut needle, dimple needle, rough-surface needle (rough over the sections of needle located 3-6 mm from the tip), and a needle with four side holes (side holes covered by the sheath). An unmodified commercially available puncture needle was used as a control. Five interventional radiologists evaluated image quality according to the following classification grade:?I, invisible; II, poor; III, moderate; IV, good; V, excellent. RESULTS: The highest score for needle visualization was obtained for the needle with four side holes. The re-cut needle scored the same as the control. Multiple comparisons were conducted using overall evaluation scores among the commercially available needle, dimple needle, rough-surface needle (3-6 mm), and the needle with four side holes. A significantly higher score was obtained for the needle with four side holes (P < 0.05/6). CONCLUSION: The needle with four side holes was prominently visualized and gained a significantly higher score (compared with the other needles) in a phantom evaluation.
