Composite sandwich lattice structure

A lattice type structural panel is described. The panel utilizes the unidirectional character of filamentary epoxy impregnated composites. The panels are stiff lightweight structures for use in constructing space satellites and the like

Constructing space-filling curves of compact connected manifolds

AbstractLet M be a compact connected (topological) manifold of finite- or infinite-dimension n. Let 0 ⩽ r ⩽ 1 be arbitrary but fixed. We construct in this paper a space-filling curve f from [0,1] onto M, under which M is the image of a compact set A of Hausdorff dimension r. Moreover, the restriction of f to A is one-to-one over the image of a dense subset provided that 0 ⩽ r ⩽ log|2n/log(2n + 2). The proof is based on the special case where M is the Hilbert cube [0,1]ω

The Disciplines of Geography: Constructing Space in the Ancient World

This article serves as introduction to a special double issue of the journal, comprised of seven articles that center on the theme of space and place in the ancient world. The essays examine the ways in which borders, frontiers, and the lands beyond them were created, defined, and maintained in the ancient world. They consider such themes within the context of the Old Assyrian period, the Hittite empire, and the Neo-Assyrian empire, as well as within the broader scope of Biblical texts and the Graeco-Roman world. As we only see evidence of a documented, physical, and thus fixed map in the later stages of Mesopotamian history, the ancient world primarily conceived of space through mental maps rather than physical ones. Thus, while the societies of the ancient Near East integrated knowledge gained by actual contact with distant lands into their world view, it was also informed by the literary conceptions of those same spaces. These mental maps were unsurprisingly prone to shifting over time, changing as the social conceptions of the world itself, its border and frontiers, the lands that lay beyond them and how those places might be defined, also changed. These papers question the intersection of concrete and fantastical, or real and imagined, that existed in both the ancient and pre-modern world, where distant locations become elaborately embroidered by fantastical constructions, despite the concrete connections of travel, trade, and even military enterprise

Caregiver Engagement in Religious Urban Elementary Schools

This article examines how school leaders in a religious school serving traditionally marginalized students improve their school communities through constructing space for caregiver engagement. This study suggests how counter-narratives of critical care can inform social justice leadership in schools. The results, from a case study of a Catholic urban elementary school that uses innovative and effective strategies to engage caregivers, show that educational leaders create spaces for engaging caregivers by developing relationships with them and systematically reducing barriers to their participation in the school community. Analyzing these results through the critical care theory lens illuminates how these spaces value diverse forms of social and cultural capital are strengthened by alliances with nontraditional support structures. This research contributes to our evolving understanding of caregiver engagement by presenting a textured analysis of a case study as viewed through a critical care conceptual framework

Emergent spacetime from modular motives

The program of constructing spacetime geometry from string theoretic modular forms is extended to Calabi-Yau varieties of dimensions two, three, and four, as well as higher rank motives. Modular forms on the worldsheet can be constructed from the geometry of spacetime by computing the L-functions associated to omega motives of Calabi-Yau varieties, generated by their holomorphic $n-$forms via Galois representations. The modular forms that emerge from the omega motive and other motives of the intermediate cohomology are related to characters of the underlying rational conformal field theory. The converse problem of constructing space from string theory proceeds in the class of diagonal theories by determining the motives associated to modular forms in the category of motives with complex multiplication. The emerging picture indicates that the L-function can be interpreted as a map from the geometric category of motives to the category of conformal field theories on the worldsheet.Comment: 40 page

Cyclic division algebras: a tool for space-time coding

Multiple antennas at both the transmitter and receiver ends of a wireless digital transmission channel may increase both data rate and reliability. Reliable high rate transmission over such channels can only be achieved through Space–Time coding. Rank and determinant code design criteria have been proposed to enhance diversity and coding gain. The special case of full-diversity criterion requires that the difference of any two distinct codewords has full rank. Extensive work has been done on Space–Time coding, aiming at finding fully diverse codes with high rate. Division algebras have been proposed as a new tool for constructing Space–Time codes, since they are non-commutative algebras that naturally yield linear fully diverse codes. Their algebraic properties can thus be further exploited to improve the design of good codes. The aim of this work is to provide a tutorial introduction to the algebraic tools involved in the design of codes based on cyclic division algebras. The different design criteria involved will be illustrated, including the constellation shaping, the information lossless property, the non-vanishing determinant property, and the diversity multiplexing trade-off. The final target is to give the complete mathematical background underlying the construction of the Golden code and the other Perfect Space–Time block codes

Constructing Space and Framing the Beholder: Problems and Solutions in Gustave Caillebotte’s Compositions

This project investigates Gustave Caillebotte\u27s techniques of constructing and arranging space. Previous scholarship has examined the artist\u27s works in light of external, social, and historic evidence, therefore, my account will provide a detailed formal analysis of the works considering the role of the intended viewer. In looking closely Young Man Playing the Piano, Man at his Bath, and Pont de l’Europe, I argue that the viewpoint assigned to the beholder projects an irreconcilable vision of modernity. Caillebotte utilizes elements of representational painting--viewpoints, the illusion of time, the arrangement of people within space, and the built structures that describe space--in order to involve the viewer in an interaction that corresponds to the represented space