Nesting (process)

Abstract: Incubation is an energetically demanding process for parents, in part because of the thermodynamic costs of maintaining egg temperature. One might predict that aspects of nest construction—in particular, the thermodynamic properties of the nesting material and the degree to which the nest provides shelter from the wind—would have important effects on thermodynamic costs. However, little is known about the relative importance of those factors. Here, we investigate egg cooling rates in several commonly used nesting materials and in various wind speeds and examine the effect on those rates of wetting the materials. Nesting materials differ greatly in their insulating properties; feather down is the best insulator, and grass the worst. When the materials are wet, eggs cool much more rapidly, differences between materials tend to diminish, and down becomes the worst insulator. Hence, there may be significant selection pressure to choose particular nesting materials, but materials may be better or wors...

Abstract: In this paper, a genetic and heuristic approach is proposed for the nesting of multiple two-dimensional (2-D) shaped parts in multiple 2-D shaped sheets with the aim of minimizing the wastage of the sheet material. The paper proposes a new method of representing the sheet and part geometries in discrete form to arrange the parts on the sheet quickly, irrespective of the complexity in the geometry of the sheets and parts. The proposed heuristic approach considers the sheets and parts in a sequential manner and arranges the parts on the sheets using the bottom-left strategy. The genetic algorithm generates the best sequence of the sheets and parts for nesting the parts on multiple sheets, utilizing the sheet material optimally. The effectiveness of the proposed approach is shown by comparing the results obtained with the present approach to those obtained with the approaches proposed by Jakobs (Eur J Oper Res, 88 (1996) 165), Ramesh Babu and Ramesh Babu (Int J Prod Res, 37(7) 1999 1625), and Jain and Chang (Engng Comput, 14 (1998) 206). The generic nature of the present approach is illustrated by considering a variety of parts, ranging from a simple rectangular shape to a highly irregular shape, in different combinations with or without grain orientation constraint, apart from nesting of multiple irregular shaped parts in multiple sheets of complex geometry.

Abstract: A module comprised of a plurality of light emitting diode ("LED") lamps or other light emitting devices and a metal nesting frame with flexible joints between each row of LED bus bars is described. The flexible joint between the rows of LED bus bars allows the module to be assembled flat, which eases its manufacture. After the LED lamps or other light emitting devices have been mounted on the nesting frame, the flexible joints allow the module to be formed to fit within or on a complex three dimensional space. After forming, the metal nesting frame is still rigid enough to support the finished module in the desired shape.