Buckling and vibration of periodic lattice structures

Lattice booms and platforms composed of flexible members or large diameter rings which may be stiffened by cables in order to support membrane-like antennas or reflector surfaces are the main components of some large space structures. The nature of these structures, repetitive geometry with few different members, makes possible relatively simple solutions for buckling and vibration of a certain class of these structures. Each member is represented by a stiffness matrix derived from the exact solution of the beam column equation. This transcendental matrix gives the current member stiffness at any end load or frequency. Using conventional finite element techniques, equilibrium equations can be written involving displacements and rotations of a typical node and its neighbors. The assumptions of a simple trigonometric mode shape is found to satisfy these equations exactly; thus the entire problem is governed by just one 6 x 6 matrix equation involving the amplitude of the displacement and rotation mode shapes. The boundary conditions implied by this solution are simple supported ends for the column type configurations

Chinatown Black Tigers: Black Masculinity and Chinese Heroism in Frank Chin\u27s Gunga Din Highway

Images of ominous villains and asexual heroes in literature and mainstream American culture tend to relegate Asian American men to limited expressions of masculinity. These emasculating images deny Asian American men elements of traditional masculinity, including agency and strength. Many recognize the efforts of Frank Chin, a Chinese American novelist, to confront, expose, and revise such images by relying on a tradition of Chinese heroism. In Gunga Din Highway (1994), however, Chin creates an Asian American masculinity based on elements of both the Chinese heroic tradition and a distinct brand of African American masculinity manifested in the work of Ishmael Reed, an African American novelist and essayist known for his outspoken style.^1 Rather than transforming traditional masculinity to include Asian American manhood, Chin\u27s images of men represent an appropriation of elements from two ethnic sources that Chin uses to underscore those of Asian Americans. While deconstructing the reductive images advocated by the dominant culture, Chin critiques the very black masculinity he adopts. Ultimately he fails to envision modes of masculinity not based on dominance, yet Chin\u27s approach also can be read as the ultimate expression of Asian American individualism

Transfer of preferences on payment

Is the insolvency preference of the Inland Revenue an accessory right and is it tranferred with an assignment of the debt? On what basis is a co-obligant who pays the debt of the other obligants entitled to recover: cession mandate or unjustified enrichment

New England reservoir management

There are no author-identified significant results in this report

Financing of large corporations in 1954

Corporations - Finance

Properties which normal operators share with normal derivations and related operators

Let $S$ and $T$ be (bounded) scalar operators on a Banach space \scr X and let $C(T,S)$ be the map on \scr B(\scr X), the bounded linear operators on \scr X, defined by $C(T,S)(X)=TX-XS$ for $X$ in \scr B(\scr X). This paper was motivated by the question: to what extent does $C(T,S)$ behave like a normal operator on Hilbert space? It will be shown that $C(T,S)$ does share many of the special properties enjoyed by normal operators. For example, it is shown that the range of $C(T,S)$ meets its null space at a positive angle and that $C(T,S)$ is Hermitian if $T$ and $S$ are Hermitian. However, if \scr X is a Hilbert space then $C(T,S)$ is a spectral operator if and only if the spectrum of $T$ and the spectrum of $S$ are both finite

Product line design

We characterize the product line choice and pricing of a monopolist from the upper envelope of net marginal revenue curves to the individual product demand functions. The equilibrium product line constitutes those varieties yielding the highest upper envelope. In a generalized vertical differentiation framework, the equilibrium line is exactly the same as the first-best socially optimal line. These upper envelope and first-best optimal line findings extend to symmetric Cournot oligopoly

Energy spectra of vortex distributions in two-dimensional quantum turbulence

We theoretically explore key concepts of two-dimensional turbulence in a homogeneous compressible superfluid described by a dissipative two-dimensional Gross-Pitaeveskii equation. Such a fluid supports quantized vortices that have a size characterized by the healing length $\xi$. We show that for the divergence-free portion of the superfluid velocity field, the kinetic energy spectrum over wavenumber $k$ may be decomposed into an ultraviolet regime ($k\gg \xi^{-1}$) having a universal $k^{-3}$ scaling arising from the vortex core structure, and an infrared regime ($k\ll\xi^{-1}$) with a spectrum that arises purely from the configuration of the vortices. The Novikov power-law distribution of intervortex distances with exponent -1/3 for vortices of the same sign of circulation leads to an infrared kinetic energy spectrum with a Kolmogorov $k^{-5/3}$ power law, consistent with the existence of an inertial range. The presence of these $k^{-3}$ and $k^{-5/3}$ power laws, together with the constraint of continuity at the smallest configurational scale $k\approx\xi^{-1}$, allows us to derive a new analytical expression for the Kolmogorov constant that we test against a numerical simulation of a forced homogeneous compressible two-dimensional superfluid. The numerical simulation corroborates our analysis of the spectral features of the kinetic energy distribution, once we introduce the concept of a {\em clustered fraction} consisting of the fraction of vortices that have the same sign of circulation as their nearest neighboring vortices. Our analysis presents a new approach to understanding two-dimensional quantum turbulence and interpreting similarities and differences with classical two-dimensional turbulence, and suggests new methods to characterize vortex turbulence in two-dimensional quantum fluids via vortex position and circulation measurements.Comment: 19 pages, 8 figure