Concepts and analysis for precision segmented reflector and feed support structures

Several issues surrounding the design of a large (20-meter diameter) Precision Segmented Reflector are investigated. The concerns include development of a reflector support truss geometry that will permit deployment into the required doubly-curved shape without significant member strains. For deployable and erectable reflector support trusses, the reduction of structural redundancy was analyzed to achieve reduced weight and complexity for the designs. The stiffness and accuracy of such reduced member trusses, however, were found to be affected to a degree that is unexpected. The Precision Segmented Reflector designs were developed with performance requirements that represent the Reflector application. A novel deployable sunshade concept was developed, and a detailed parametric study of various feed support structural concepts was performed. The results of the detailed study reveal what may be the most desirable feed support structure geometry for Precision Segmented Reflector/Large Deployable Reflector applications

On panel flutter and divergence of infinitely long unstiffened and ring-stiffened thin-walled circular cylinders

A preliminary theoretical investigation of the panel flutter and divergence of infinitely long, unstiffened and ring-stiffened thin-walled circular cylinders is described. Linearized unsteady potential-flow theory is utilized in conjunction with Donnell's cylinder theory to obtain equilibrium equations for panel flutter. Where necessary, a simplified version of Flugge's cylinder theory is used to obtain greater accuracy. By applying Nyquist diagram techniques, analytical criteria for the location of stability boundaries are derived. A limited number of computed results are presented

Harvesting Memory, Preserving Home: A Cookbook of the Painted Turtle Farm/Cosechando Memoria, Preservando el Hogar: Un Libro de Cocina de la Granja de la Tortuga Pintada

About this Project In the fall of 2018, 14 of the families and 32 students from two first-year seminars, Crossing Borders: Immigration, Identity, and Development and Immigrant Stories, worked together to create this cookbook. Families submitted their favorite dishes and then invited students to their homes to demonstrate the preparation. As they cooked and ate together, students recorded the steps to make the recipe and listened as connections between food, memory, family, migration, traditions, and religion emerged. Harvesting Memory, Preserving Home: A Cookbook of the Painted Turtle Farm is the product of this undertaking. In it, we offer the collection of recipes as well as a short story from each family, bring meaning to the food we eat, the places life brings us, and the memories we share. Sobre este Projecto En el otoño de 2018, 12 de las familias y 32 estudiantes de dos clases, Cruzando Fronteras: Immigración, Identidad, y Desarrollo y Las Historias Immigrantes trabajaron juntos para cear este libro de cocina. Las familias escogieron platos con una importancia o una memoria especial para preparar en sus casas con los estudiantes. Durante el proceso de concinar y comer juntos, los estudiantes anotaron los pasos para preparar la receta. Ellos escucharon las conexiones entre la comida, la memoria, la familia, la migración, las tradiciones, y la religión. Cosechando Memoria, Preservando el Hogar: Un Libro de Cocina de la Granja de la Tortuga Pintada es el fruto de este proyecto. Ofrecemos la collección de recetas además de una historia breve de cada familia, para dar significado a los alimentos que comemos, los lugares donde la vida nos trae, y las memorias que nos compartimos

NACA Technical Notes

Report presenting a flutter analysis for rectangular wings of very low aspect ratio with a constant thickness, which used slender-body aerodynamic theory and thin-plate theory. The results show that the variation of flutter speed and mode shape with aspect ratio. Approximation of the chordwise deflection shape by use of parabolic or cubic curves yields flutter speeds in fair agreement with those of the "exact" theory for a ratio of chord to semispan less than 3 with the cubic approximation giving almost exact results

NACA Technical Notes

Note presenting a theoretical investigation of the panel flutter and divergence of infinitely long, unstiffened and ring-stiffened thin-walled circular cylinders. Linearized unsteady potential-flow theory is utilized in conjunction with Donnell's cylinder theory to obtain equilibrium equations for panel flutter

NACA Technical Reports

"A preliminary theoretical investigation of the panel flutter and divergence of infinitely long, unstiffened and ring-stiffened thin-walled circular cylinders is described. Linearized unsteady potential-flow theory is utilized in conjunction with Donnell's cylinder theory to obtain equilibrium equations for panel flutter. Where necessary, a simplified version of Flugge's cylinder theory is used to obtain greater accuracy. By applying Nyquist diagram techniques, analytical criteria for the location of stability boundaries are derived. A limited number of computed results are presented" (p. 475)