Programmable Hierarchical Kirigami

Kirigami—the Japanese art of cutting paper—has recently inspired the design of highly stretchable and morphable mechanical metamaterials that can be easily realized by embedding an array of cuts into a sheet. This study focuses on thin plastic sheets perforated with a hierarchical pattern of cuts arranged to form an array of hinged squares. It is shown that by tuning the geometric parameters of this hierarchy as well as thickness and material response of the sheets not only a variety of different buckling‐induced 3D deformation patterns can be triggered, but also the stress–strain response of the surface can be effectively programmed. Finally, it is shown that when multiple hierarchical patterns are brought together to create one combined heterogeneous surface, the mechanical response can be further tuned and information can be encrypted into and read out via the applied mechanical deformation.     

Book Reviews

When design and technology are too widely separated in the architectural curriculum, the informing knowledge of technology is not engaged as a design issue. As an outcast to the creative design process, architectural technology itself becomes outmoded: It is not thought about and developed as a partner to the expression of architecture. Design becomes disengaged from the means of making architecture and disconnected from the world and its informing environmental insights.

Lack of knowledge of technology and environment is evident in the negative and in some cases disastrous impact of buildings—some held up as design exemplars—on both the natural and human environment. To bridge the gaps that exist in the architectural curriculum, educators must establish sustaining linkages between design inspiration and technological and environmental knowledge. Technology here does not mean the mechanistic icons and artifacts of current construction techniques. It is best defined as knowledge gained in the making, the accumulated insights into architecture learned from the experience of its processes and its place. If there is agreement on this conception, only modest changes are needed to integrate design, technology, and environment throughout the curriculum.     

Cray X-MP: the birth of a supercomputer

The authors' experience in designing and manufacturing the Cray X-MP supercomputer is described. The X-MP is a multiprocessor design built on the basic architecture of the Cray-1 and incorporates the 16-gate emitter-coupled logic gate arrays used in the Cray-2 project. The goal was a two-processor machine compatible with the Cray-1 but with performance 1.5 to 2 times better. The authors examine the architectural considerations. They discuss the use of electronic design rules and CAD (computer-aided design); the packaging, interconnections, and cooling; and assembly and testing     

Cyclopropenoid fatty acid content and fatty acid composition of crude oils from twenty-five varieties of cottonseed

The cyclopropenoid acid content of oils extracted from 22 commercial varieties and 3 botanical species of cottonseed have been determined. The malvalic acid content determined by HBr titration varied from a low of 0.56% to a high of 1.17%. Iodine values of the oils ranged from 96.8 to 111.6 No definite correlation could be established between iodine value and malvalic acid content. Equations for regression lines for the major acids have been calculated from plots of fatty acid composition vs. iodine value. The high degree or correlation suggests that for commercial oils the fatty acid composition can be estimated from the iodine value. Oils of the 3 experimental types of different species showed wide variations in fatty acid composition and represented many of the maximum and minimum values reported. So. Utiliz. Res. Dev. Div., ARS, USDA. ARS, USDA.