Underwater Thruster Saturation Detection and Prevention Considering Battery Voltage Sag

ABSTRACT This paper reports on the development of a control module that detects and effectively prevents thruster saturation for an autonomous underwater vehicle (AUV). A model has been developed to approximate the maximum available thrust, per thruster, as a function of the battery voltage sag. A thruster would be considered to be in saturation if its reference input exceeds its particular output limit. This ratio can be expressed as a scalar value, which can be used to adjust the reference thrust vector that is fed to the thruster control system. This approach can minimize the total error vector in the vehicle kinematics

Simple excision and closure of a distal limb of loop colostomy prolapse by stapler device

Stomal prolapse is one of the common complications in transverse colostomy and can be managed conservatively in most cases; however, laparotomy and reconstruction of the stoma may sometimes be required, especially in case of irreducible colostomy prolapse. We have reported a simple local repair with reconstruction of the loop colostomy. We herein report a new more simple technique to avoid laparotomy and allow excision of the irreducible colostomy prolapse and complete closure of the distal limb of loop colostomy when no decompression is required in the distal limb of the stoma. In this procedure, the number of stapler and the time with blood loss for the operation can be saved

Measurement of tau polarization in e+ e- annihilation at sqrt{s}=58 GeV

The polarization of tau leptons in the reaction e+ e- --> tau+ tau- has been measured using a e+e- collider, TRISTAN, at the center-of-mass energy of 58 GeV. From the kinematical distributions of daughter particles in tau --> e nu nu-bar, mu nu nu-bar, rho nu or pi(K) nu decays, the average polarization of tau- and its forward-backward asymmetry have been evaluated to be 0.012 +- 0.058 and 0.029 +- 0.057, respectively.Comment: 18 pages, 5 figure

Development and validation of a low dose simulator for computed tomography

To develop and validate software for facilitating observer studies on the effect of radiation exposure on the diagnostic value of computed tomography (CT). A low dose simulator was developed which adds noise to the raw CT data. For validation two phantoms were used: a cylindrical test object and an anthropomorphic phantom. Images of both were acquired at different dose levels by changing the tube current of the acquisition (500 mA to 20 mA in five steps). Additionally, low dose simulations were performed from 500 mA downwards to 20 mA in the same steps. Noise was measured within the cylindrical test object and in the anthropomorphic phantom. Finally, noise power spectra (NPS) were measured in water. The low dose simulator yielded similar image quality compared with actual low dose acquisitions. Mean difference in noise over all comparisons between actual and simulated images was 5.7 +/- 4.6% for the cylindrical test object and 3.3 +/- 2.6% for the anthropomorphic phantom. NPS measurements showed that the general shape and intensity are similar. The developed low dose simulator creates images that accurately represent the image quality of acquisitions at lower dose levels and is suitable for application in clinical studies.Radiolog