Motivated by the requirement for pinpoint landing in futureMarsmissions, we consider the problemofminimumfuel powered terminal descent to a prescribed landing site. The first-order necessary conditions are derived and interpreted for a point-mass model with throttle and thrust angle control and for rigid-bodymodel with throttle and angular velocity control, clarifying the characteristics of the...

Introduction: Due to its simplicity, fast response and high reliability, ion chamber detectors are one of the most suitable dosimetry instruments for X and gamma rays. The dosimeter    of photon beams, which used in radiotherapy centers, requires high accuracy and should pass requirements of IEC 60731 standards. About 80 percent of the IEC 60731 standard tests such as stabil...

In this paper a new process is presented for improving efficiency of cyclone de-dusting systems. The cyclone is coupled with a specially designed cylindrical chamber which includes a rotating tube inside it with air impinging nuzzles, drilled on the peripheral surface of the tube. The nuzzles help in pushing and throwing the particles to the outer radius distances during downward flow of du...

Clinically in both the congenital and the acquired ocular disease, there is an acute focal chorioretinitis having its active onset of recurrence between ages 11 and 40 years old. Lesions may be single, variable in size, and are usually posterior to the equator. There is exudation into the vitreous and flare and cells in the anterior chamber. Vitreous may detach from the retina, with hemispheric...