Dynamics Modeling and Simulation for Moving-mass Reentry Vehicle
With respect to hypersonic re-entry vehicle, by applying the Newton-Euler's method, the six-degrees of freedom(6-DOF) dynamical equations of moving mass for a re-entry vehicle are derived and the control mechanism is analyzed according to the dynamical equations. Under the environment of Matlab, the 6-DOF trajectory simulation is presented based on the dynamical equations considering the earth's rotation and non-spherosomes factors, the cross-range and down-range of the impact point cause by lateral movement of the moving masses are computed by simulation and the results validate the feasibility of moving mass control.
Modeling of Mars Entry Vehicles with an Internal Sole-moving-mass Actuator
This paper investigates the deployment of an internal sole-moving-mass actuator in Mars entry vehicles. Given the extreme environment of Mars atmosphere, moving mass control has gained plenty of advantages in efficiency, cost and reliability over aerodynamic flap and thruster-based control. First, a model of moving-mass dynamics is derived using Kane’s Method based on the proposed moving mass configuration. In such a multi-body system, the interactions between the moving mass and the vehicle are focused on during the modeling procedure. Then, several key parameters of the moving mass configuration are determined through analysis. Finally, the manipulation characteristics are verified to ensure the capability of mission accomplishment. Simulation results indicate the applicability and effectiveness of the proposed sole-moving-mass actuator.
Comparison of a Radiometric Procedure with Conventional Methods for Identification of Neisseria
A radiometric procedure was compared with the conventional cystine tryptic agar (CTA) sugar fermentation method for identification of Neisseria species. Four different ATCC cultures of Neisseria were identified by both procedures with identical results. The only difference noted was that the radiometric procedure required 3 h for completion, whereas the conventional CTA sugar method required overnight incubation. The radiometric procedure was also compared with the fluorescent antibody (FA) and CTA methods for identification of Neisseria gonorrhoeae. The organisms examined were gram-negative, oxidase-positive diplococci isolated from 49 clinical specimens sent to the laboratory for bacteriological analysis. Results obtained by both CTA and FA procedures were comparable. However, the radioisotope method appeared to be superior to the other two methods in that only one isolate identified as positive by both the CTA and FA methods was not identified radiometrically, whereas four isolates positive by the radiometric method were not identified by the other two procedures. Thus, a total of seven more positive identifications were made radiometrically than by either of the two other methods. All positive identifications were confirmed by a reference laboratory. These results indicate that the radiometric procedure is more rapid and reliable as compared with both the CTA and direct FA methods and, thus, may serve as a valuable addition to the methodology available for diagnostic microbiology.