Vaughn College of Aeronautics and Technology

About: Vaughn College of Aeronautics and Technology is a education organization based out in New York, New York, United States. It is known for research contribution in the topics: Gravitational microlensing & Planetary system. The organization has 727 authors who have published 708 publications receiving 14082 citations. The organization is also known as: College of Aeronautics.

Chattering-free trending law for discrete-time sliding mode control

Abstract: As the trending law of discrete-time sliding mode control is in different forms and difficult to avoid chattering,a general form of it is proposed,and the reaching condition without chattering is given with the academic proof,which provides a theory basis in general for the design and research of the chattering-free trending law for the discrete-time sliding mode control.As to the uncertain system that satisfies matching condition,the method to infer the convergent region of the switch function and the minimal value of it without chattering are provided.The classical exponential trending law is improved as a case of using the reaching condition without chattering based on its general form,which shows the effectiveness of the proposed method.

Engineering with Polymeric Materials

Abstract: Summary The rapid expansion of plastics and other polymeric materials into the general consumer market over the last few years is now being followed by an increasing use of these materials in more severe engineering applications. It is becoming necessary therefore for engineers to develop a familiarity with these materials commensurate with that which they already have for more conventional engineering materials. In many ways the physical properties of polymeric materials are highly complex and their description and relation to structure present real problems. This article presents, in a simple way, some of the background to our current level of understanding of the relation between structure and mechanical properties; gives some examples of how polymeric materials are being used; and discusses some of the problems of designing in these materials, which present a real challenge to both the physicist and the engineer.

Deformation Equations for Non-Circular Cylinders

Abstract: As far as is known, no explicit solution exists in the literature for the displacement equations in u, v and w , for a uniform cylinder of arbitrary cross section subjected to a lateral pressure loading. However, the advent of Ref. 1 now makes available an admirable treatise devoted entirely to the analysis of thin elastic shells. The equations developed in this reference apply only to linear problems, i.e. the displacements are assumed to be small in comparison with the thickness of the shell, but they are general enough to include all shells of arbitrary curvature. Unfortunately the generality of these equations inhibits their immediate use to cylindrical shell problems, and it is the purpose of this note to present the essential features of the theory for non-circular cylinders.

MOA 2011-BLG-028Lb: a Neptune-mass Microlensing Planet in the Galactic Bulge

Abstract: We present the discovery of a Neptune-mass planet orbiting a 0.8 +- 0.3 M_Sun star in the Galactic bulge. The planet manifested itself during the microlensing event MOA 2011-BLG-028/OGLE-2011-BLG-0203 as a low-mass companion to the lens star. The analysis of the light curve provides the measurement of the mass ratio: (1.2 +- 0.2) x 10^-4, which indicates the mass of the planet to be 12-60 Earth masses. The lensing system is located at 7.3 +- 0.7 kpc away from the Earth near the direction to Baade's Window. The projected separation of the planet, at the time of the microlensing event, was 3.1-5.2 AU. Although the "microlens parallax" effect is not detected in the light curve of this event, preventing the actual mass measurement, the uncertainties of mass and distance estimation are narrowed by the measurement of the source star proper motion on the OGLE-III images spanning eight years, and by the low amount of blended light seen, proving that the host star cannot be too bright and massive. We also discuss the inclusion of undetected parallax and orbital motion effects into the models, and their influence onto the final physical parameters estimates.