This REU summer project dealt mainly with analyzing data and determining the periods of certain types of pulsating variable stars called RR Lyraes and Cepheids. Pulsating variables periodically change in brightness over a certain amount of time for reasons having to do with the internal structure of the star itself. Dr. Horace Smith has been studying such variables in our neighboring galaxy, th...

In this paper we consider new solutions for pulsating strings. For this purpose we use the idea of the generalized ansatz for folded and circular strings in hep-th/0311004. We find the solutions to the resulting Neumann-Rosochatius integralbe system and the corrections to the energy. To do that we use the approach developed by Minahan in hep-th/0209047 and find that the corrections are quite di...

Pulsating stars have given important information in classical astronomy and are still an active research field, e.g. asteroseismology or helioseismology. By studying the rich oscillation stellar spectra, optical astronomy makes predictions for the stellar equations of state (EOS), the evolutionary age of the stars, and in the case of Cepheids one can make exact predictions for the distance of t...

We present the results of a nonadiabatic, linear stability analysis of models of very low-mass stars (VLMSs) and brown dwarfs (BDs) during the deuterium burning phase in the center. We find unstable fundamental modes with periods varying between ∼5 hr for a 0.1 M⊙ star and ∼1 hr for a 0.02 M⊙ BD. The growth time of the instability decreases with decreasing mass and remains well below the deuter...

Recent observations at the magnetopause and of the high-latitude ionosphere, suggest that the cusp may be pulsed in nature. Specifically ground-based observations in the dayside auroral oval reveal transient optical features accompanied by bursts of enhanced plasma flow. Also, recent interpretation has shown cusp satellite data to be consistent with a burst of enhanced reconnection. In this pap...

Based on the Lifshitz theory we show that the illumination of one (Si) plate in the three-layer systems Au–ethanol–Si, Si–ethanol–Si and α-Al2O3–ethanol– Si with laser pulses can change the Casimir attraction to Casimir repulsion and vice versa. The proposed effect opens novel opportunities in nanotechnology to actuate the periodic movement in electroand optomechanical micromachines based entir...

nowadays the use of the switched reluctance motors (srms) has been considerably increased in various home and industrial applications. despite of many advantages of this type of motors, such as simple structure, low cost, and high reliability, the main disadvantage of them is the generation of high torque pulsation. this paper presents a novel method to optimize a typical srm such that the torq...

background: reusing orthodontic mini-screws would reduce treatment cost and lead to more use of mini-screws and improvement of orthodontic treatments. this study has assessed the effects of reprocessing and reusing the titanium mini-screws on their maximum insertion, removal and fracture torque (ft). materials and methods: in this experimental study, 20 titanium mini-screws (1.6-mm × 8-mm) were...

Spacely Sprockets (a pseudonym) specializes in the manufacture of aerospace products. The corporate mission of Spacely Sprockets is simply “client success”, which drives the expectation that every product must work the first time, every time. Spacely Sprockets relies on accurate application of torque when tightening mechanical fasteners during the manufacturing process. Torque is a twisting for...

Some ?weeks ago, a Constable came into hospital with the above ailment. The tumour was well defined, as large as a cricket ball, and situated above the umbilicus. I desired Sub-Assistant Surgeon Soorjee Narain Singh, at that time in charge of the dispensary, to diagnose and report upon the case, lie decided that it was a foecal tumour, lying upon the aorta, and pointed out with great clearness ...