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.

Life enhancement of fatigue-aged fastener holes using the cold expansion process

Abstract: This paper examines the benefits of cold expanding fastener holes at various stages of the fatigue life in a 2024-T351 low-load transfer joint. The specimens were pre-cycled to 25, 50 and 7...

Study on Failure Simulation and Fatigue Life Prediction of BGA Solder Joint Under Random Vibration

Abstract: Aiming at the problem of BGA solder joint failure under random vibration, random vibration simulation and fatigue life prediction were studied, and the results were verified by experiments. Firstly, the three-dimensional finite element model of the solder joint was established by ANSYS software. The vibration characteristics of the model were obtained by analyzing the first five modes. Then the random vibration simulation analysis was performed. It was found that the solder joint had 3 extremely vulnerable areas. After that, the fatigue life of the solder joint was estimated to be 601mins using the empirical formula and three-band technique. Finally, a random vibration test was conducted. The test results show that there are 3 failure modes in the solder joint, which are consistent with the simulation analysis results; and the fatigue lifetime of the solder joint is 697mins, which means the accuracy of the fatigue life prediction is 86.2%.

Thermotropic Liquid-Crystalline and Light-Emitting Properties of Bis(4-aalkoxyphenyl) Viologen Bis(triflimide) Salts

Abstract: A series of bis(4-alkoxyphenyl) viologen bis(triflimide) salts with alkoxy chains of different lengths were synthesized by the metathesis reaction of respective bis(4-alkoxyphenyl) viologen dichloride salts, which were in turn prepared from the reaction of Zincke salt with the corresponding 4-n-alkoxyanilines, with lithium triflimide in methanol. Their chemical structures were characterized by 1H and 13C nuclear magnetic resonance spectra and elemental analysis. Their thermotropic liquid-crystalline (LC) properties were examined by differential scanning calorimetry, polarizing optical microscopy, and variable temperature X-ray diffraction. Salts with short length alkoxy chains had crystal-to-liquid transitions. Salts of intermediate length alkoxy chains showed both crystal-to-smectic A (SmA) transitions, Tms, and SmA-to-isotropic transitions, Tis. Those with longer length of alkoxy chains had relatively low Tms at which they formed the SmA phases that persisted up to the decomposition at high temperatures. As expected, all of them had excellent thermal stabilities in the temperature range of 330-370 °C. Their light-emitting properties in methanol were also included.

Chiral and orientationally ordered fluid mesophases formed by oxadiazole bisaniline based achiral bent mesogens

Abstract: Development of new liquid crystalline materials exhibiting interesting properties and phases continues to be an enabling enterprise in the forward march of their successful display and non-display ...