Geometric control of quadrotors provides a way to control the 3D position and a yaw angle of the ... more Geometric control of quadrotors provides a way to control the 3D position and a yaw angle of the robot with a larger stability region than linearized controllers, but is still singular for some orientations. This singularity exists even if SO(3) is parameterized in a non-singular way such as with unit quaternions. Recent advances using the Hopf Fibration have eliminated these singularities using multiple coordinate charts and switching between them to avoid singularities. We further extend the envelope of geometric control for quadrotors to a system where the propellers can reverse direction and produce negative forces using additional charts. We show that our proposed controller is stable in hovering a robot upright and upside down. We then show how to extend trajectory generation using differentially flat coordinates to optimize trajectories using multiple charts to produce trajectories which can transition between upright and upside down.
Bronchopleural fistula (BPF) is a communication between the pleural space and the bronchial tree,... more Bronchopleural fistula (BPF) is a communication between the pleural space and the bronchial tree, and is associated with significant morbidity and mortality. Treatment options for BPF include surgical closure and medical therapy. In an unstable patient, invasive surgical intervention is not an option. In this article, we report the case of a 61-year-old man who developed pneumothorax with a large BPF after a bronchoscopic resection of a malignant endobronchial lesion. We inserted a piece of 1.5Â 1.5-cm Xeroform dressing to seal the massive air leak with successful closure of the BPF. To our knowledge, this is the first report of successful closure of a massive BPF with Xeroform dressing in an acutely decompensating patient.
the other associating with another sulfur at a terminal carbon. It should be pointed out that ene... more the other associating with another sulfur at a terminal carbon. It should be pointed out that energy transfer would be possible froni the middle dye molecule fluorescing at 510 mk to the terminal dye molecule absorbing at 520 nip. Less photosensitivity is found in the mercaptoethanol complex than in the dimercaptopropanol complex. The phototropism is related to a lightinduced electron transfer which is evidenced by the change of photovoltaic effect and electron spin resonance absorption. This indicates that the two sulfurs interacting with the same dye molecules differ in the capability of charge transfer. The fact that the same conjugated molecules associating with sulfhydryl groups in a different environment show different spectral and photochemical characteristics would be significant for the function of SH groups in energetics of biological systems. Acknowledgments. The author wishes to thank Miss Maria Tavla and Mrs. Frances Pearlmutter for their valuable assistance.
Geometric control of quadrotors provides a way to control the 3D position and a yaw angle of the ... more Geometric control of quadrotors provides a way to control the 3D position and a yaw angle of the robot with a larger stability region than linearized controllers, but is still singular for some orientations. This singularity exists even if SO(3) is parameterized in a non-singular way such as with unit quaternions. Recent advances using the Hopf Fibration have eliminated these singularities using multiple coordinate charts and switching between them to avoid singularities. We further extend the envelope of geometric control for quadrotors to a system where the propellers can reverse direction and produce negative forces using additional charts. We show that our proposed controller is stable in hovering a robot upright and upside down. We then show how to extend trajectory generation using differentially flat coordinates to optimize trajectories using multiple charts to produce trajectories which can transition between upright and upside down.
Bronchopleural fistula (BPF) is a communication between the pleural space and the bronchial tree,... more Bronchopleural fistula (BPF) is a communication between the pleural space and the bronchial tree, and is associated with significant morbidity and mortality. Treatment options for BPF include surgical closure and medical therapy. In an unstable patient, invasive surgical intervention is not an option. In this article, we report the case of a 61-year-old man who developed pneumothorax with a large BPF after a bronchoscopic resection of a malignant endobronchial lesion. We inserted a piece of 1.5Â 1.5-cm Xeroform dressing to seal the massive air leak with successful closure of the BPF. To our knowledge, this is the first report of successful closure of a massive BPF with Xeroform dressing in an acutely decompensating patient.
the other associating with another sulfur at a terminal carbon. It should be pointed out that ene... more the other associating with another sulfur at a terminal carbon. It should be pointed out that energy transfer would be possible froni the middle dye molecule fluorescing at 510 mk to the terminal dye molecule absorbing at 520 nip. Less photosensitivity is found in the mercaptoethanol complex than in the dimercaptopropanol complex. The phototropism is related to a lightinduced electron transfer which is evidenced by the change of photovoltaic effect and electron spin resonance absorption. This indicates that the two sulfurs interacting with the same dye molecules differ in the capability of charge transfer. The fact that the same conjugated molecules associating with sulfhydryl groups in a different environment show different spectral and photochemical characteristics would be significant for the function of SH groups in energetics of biological systems. Acknowledgments. The author wishes to thank Miss Maria Tavla and Mrs. Frances Pearlmutter for their valuable assistance.
Uploads
Papers by Ahmed Zahra