Large Cutouts Research Articles

Predicting canopy and trunk cross-sectional area of silver linden ( Tilia tomentosa) in confined planting cutouts

Urbanized land is characterized by the dominance of paved surfaces. Increasing tree canopy in urbanized areas has been identified as an effective way to reduce stormwater runoff, sequester carbon, improve air and water quality, and otherwise mitigate the environmental impacts and increase the livability of cities. However, attaining sufficient tree canopy in urban areas remains an elusive goal. Site design characteristics such as cutout size may limit urban tree growth and complicate efforts to predict future canopy, especially in highly paved systems such as parking lots. We studied 25 silver lindens ( Tilia tomentosa Moench) grown for 14 years at one site, in pavement cutouts of various sizes. Regression analysis, even on these limited data, indicated a strong relationship between tree size and canopy projection area and unpaved soil surface area, but not soil depth. Cutout size explained 70% of the variability in tree canopy projection area and 77% of the variability in trunk cross-sectional area. The addition of other variables, such as soil bulk density, did not improve the model. Trees growing in parking lot cutouts <5.3 m 2 attained only limited size, regardless of the level of soil compaction. In larger cutouts, however, increases in soil bulk density from 1.1 to 1.5 Mg/m 3 were associated with a 70% reduction in trunk cross-sectional area. In order to create urban sites with a sustainable tree canopy, site design must provide large areas of uncompacted soil for trees and protect this soil from compaction during use. Urban tree growth models that incorporate cutout characteristics are needed to predict future canopy area with confidence.

Multilayered Finite-Difference Method (MFDM) for Modeling of Package and Printed Circuit Board Planes

Power/ground planes in electronic packaging can be a major factor for noise coupling. There can be noise coupling not only in the transversal direction between two planes, but also vertically from one plane pair to another through the apertures and via holes. Due to the large size of the power/ground planes, it is difficult to analyze them using full-wave simulators. It is known that the finite-difference solution of the Helmholtz equation provides a faster approach with comparable accuracy. For multilayered planes and arbitrary geometries with aperture coupling, we present a multilayered finite-difference method (MFDM). It provides an accurate representation of wrap-around currents, which have not been modeled earlier, for large cutouts. Estimation of the influence of such coupling effects are essential especially for a successful design of mixed-signal systems. This method allows to consider realistic structures, which would be prohibitive to simulate using full-wave simulators.

Stochastic Finite Element Buckling Analysis of Laminated Plates With Circular Cutout Under Uniaxial Compression

A generalized stochastic buckling analysis of laminated composite plates, with and without centrally located circular cutouts having random material properties, is presented under uniaxial compressive loading. In this analysis, the layerwise plate model is used to solve both prebuckling and buckling problems. The stochastic analysis is done based on mean centered first-order perturbation technique. The mean buckling strength of composite plates is validated with results available in the literature. It has been observed that the present analysis can predict buckling load accurately even for plates with large cutouts. Micromechanics based approach is used to study the effect of variation in microlevel constituents on the effective macrolevel properties like elastic moduli. Consequently, the effect of uncertainty in these material properties on the buckling strength of the laminated plates is studied. Parametric studies are carried out to see the effect of hole size, layups, and boundary conditions on the mean and variance of plate buckling strength.

Sincerely Dancing: Bill T. Jones's Sleight-of-Hand

On a rainy night in January 2002, I took a train uptown to meet a friend outside Lincoln Center. After a strange autumn, when no performance seemed as compelling as the dramas unfolding on New York City streets, the theatres were suddenly full again and it was with a certain amount of relief that a crowd gathered to see the Bill T. Jones/Arnie Zane Dance Company in concert with the Chamber Music Society. Previews in the Village Voice and the New York Times had been clear about what we would see: after years of anger and politics, wrote one journalist, Jones was reported to be searching [...] for beauty (in Perron 2002:B6; see also Jowitt 2002, and Greskovic 2002). These words became a road map to understanding Jones's new work, repeated in various publications and ostensibly taken at face value. Yet, who would argue that earlier and controversial works like Last Supper at Uncle Tom's Cabin or Still/ Here were not beautiful? Nevertheless, his often-quoted perspective became the reigning lens through which to approach the new material. Arguably the most articulate choreographer of this generation, Jones wields the English language as fiercely as he does dance and gesture. His words have come to us in the countless interviews, lectures, and published writings he has offered over a career spanning 25 years, as well as in his consistent use of text in his performances. Fueled in part by the necessity of response to the critical reaction his work has compelled; in part by his interest and immersion in performance art as distinct from dance; and in part by a unique commitment to grappling with the history of the body and to dancing the discourses of power as they play out in America, Jones talks. And, in each instance, these words constitute an equally significant performance field forJones. Yet, for viewers, they have posed an enormous challenge to move with facility between the familiar and presumedly legible realm of spoken language and the more enigmatic realm of the moving, dancing body. In the case of the Lincoln Center performance, what did we see? The night began with Verbum, a beautiful if banal dance set to Beethoven's String Quartet in F Major, Opus 135. Eight dancers performed idiosyncratic gestures alongside the classic extensions, leaps, and falls of a ballet/modern hybrid. Dressed in silver, they moved through and around a silver set designed by Bjorn Amelan, which consisted of three large cutouts that appeared alternately as portals or ciphers, hearts or women's genitalia. The dancing was lovely, and abstract. There was a renewed engagement with contact improv, a foundational technique forJones from his college

The collapse of composite cylindrical panels with various thickness using finite element analysis

This study compared numerical collapse results of graphite/epoxy cylindrical panels with free vertical edges undergoing axial compression for three different shell theories. Symmetric quasi-isotropic laminates were investigated using solid panels and panels with five different centralized cutouts with three thicknesses. The theories compared in the study were the simplified large displacement moderate rotation (SLR) theory, the Donnell cylindrical shell (modified Donnell) theory, and the classical Donnell theory. The purpose of the study was to determine when large rotations and through-the-thickness shear start to become important in the numerical collapse analysis of cylindrical composite shells. By observing cases where the numerical collapse results for each of the three theories differed noticeably (> 3%), it could be determined when large rotations and through-the-thickness shear were important. The effects of large rotations were noticed in nearly all of the panels with large cutouts (>3% panel area). Large rotations were also found to be important for thicker panels with either no cutout or a small cutout. The effects of through-the-thickness shear were only noticed in the thickest panels with large cutouts.

Solar-powered electrocuting trap for controlling house flies and stable flies (Diptera: Muscidae).

A portable trap was constructed that was visually attractive to house flies, Musca domestica L., and stable flies, Stomoxys calcitrans (L.), outdoors. The trap was made of a white and yellow pyramid placed on top of a white vertical base that had large cutouts in each side. Attracted flies were killed by means of solar-powered electrocuting grids. Three traps killed an average of 1,360 house flies and 1,190 stable flies per day at a manure dump and were effective in attracting flies under both cool (< 23 degrees C) and warm (> 30 degrees C) temperatures. Both species of flies were most attracted to the eastern side of the trap, but house flies preferred yellow in cool mornings and white in warm afternoons. When air temperatures were > 30 degrees C, both house flies and stable flies went into the shaded base of the trap or into tunnels. Most house flies were killed on the pyramidal top of the trap, whereas most stable flies were killed on the vertical base. Opaque fiberglass tunnels with central electrocuting grids were simpler and cheaper, although less effective, for stable flies.

Analysis of the stress-strain state of a shell structure with a large cutout

The finite-element method is applied to analyze the stress-strain state of a composite structure consisting of a shell supported by longitudinal and transverse beams with an internal deck also supported by longitudinal and transverse beams. The analysis reveals the presence of stress concentrations near the cutout, at the application points of concentrated forces, and near the inclined frames.

Experimental collapse determination of cylindrical composite panels with large cutouts under axial load

An experimental program has been carried out to evaluate the effect of large rectangular cutouts on the collapse of cylindrical composite panels. The effects of boundary conditions and residual stresses are considered. Comparisons are made between experimental and finite element results. The finite element analysis was carried out using the STAGS C-1 computer program.

Analysis of a Large Cutout in a Circular Silo Wall

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ANALYSIS OF WING-FUSELAGE STRUCTURE INTERACTION UNDER ASYMMETRIC TORQUE

The present paper solves the arrangement of the wing and fuselage structures with respect to the relative position of the large cutouts in both airframe parts. The finite element method based on displacement field is used for the analysis of wing structure ,while the matrix force method as given by Prof. Argyris is used for the analysis of fuselage structure. A computer program for the combined displacement-force method is constructed. Numerical examples, representing different arrangements are included which illustrate the application of the method to practical problems.The ciculated results are compared with those obtained by measurements.

Modal density of honeycomb plates

Honeycomb plates are much stiffer than uniform plates of similar mass and consequently their modal density is relatively low. This report describes an experimental study of the modal density of uniform honeycomb plates undertaken to verify the theoretical results available in the literature. This work was then extended to determine the effect of a large cut-out in the centre of the honeycomb panel typical of a spacecraft platform. It was confirmed that the area of the panel is the controlling parameter. Finally, the effect of additional masses, inserts and edge stiffeners was studied. A procedure for allowing for these components was developed and confirmed by experiment. When corrections are made for these effects the theory gives a reasonable estimate of the broad band frequency average (500 Hz bandwidths are usually required) modal density of typical spacecraft components such as platforms and side panels.

Stresses around large circular holes in uniform circular cylindrical shells

An experimental and finite element analysis of a uniform cylindrical shell with a large circular cut-out is presented. In this analysis three hole sizes are considered, namely μ = 2.037, 4.084, and 6.344 (where μ = {[12(1 - y2)]1/4/2} × [ a/( Rt)1/2]), for loadings of axial compression, torsion and three point bending. The experimental results are the only ones available for cylindrical shells with large values of μ (except for one graph by Savin (1)†), while for three point bending there is no previously published theoretical or analytical results. Good agreement is found between the calculated and experimental stresses around the holes.

Stability and vibrations of rectangular three-layer plates with large cutouts

Stability and vibrations of rectangular three-layer plates with large cutouts

Investigations on a model dome with arched cut-outs

Summary Experimental investigations on a model dome of varying thickness and with large arched cut-outs around the base are described. These investigations include the determination of strain distributions under the action of uniform and nonuniform conditions of moment and thrust at the base, and the confirmation of an approximate method of analysis developed to predict the structural behaviour.

Structural Analysis and Influence Coefficients for Delta Wings

A method is presented for determining the stresses and de~ formations in delta wings of multispar construction having chord wise ribs and thin cover sheets. The spars need not be parallel, and the cover sheets can have large cutouts. The individual spars may be clamped, simply supported, or free at the root. The method is based on the interaction between the bending stiffnesses of the spars and ribs with effective cover sheet and the torsional stiffness of the cover sheet. The method is well suited to the use of high-speed computing machines.

Stress Analysis of Circular Frames in a Non-tapering Fuselage

SummaryThe problem of the stress analysis of circular fuselage frames has been investigated by a number of authors; the analyses are, necessarily, rather mathematical in nature although in some cases the final results have been presented in extremely practical form. The present paper offers, in non-mathematical language, a short account of the fundamentals of the problem and a brief guide to the more important published literature. It also develops an approximate method for the analysis of frames using Lagrange's method for minimising a function of several inter-dependent variables. This method is shown to be particularly suitable for the analysis of frames with large cut-outs, about which little has previously been published. In addition, the underlying parameters which determine the stress distribution are deduced from the theory, and the deductions are compared with previously published work. In general, agreement is good. The paper is written throughout with a view to being of practical use in the actual stressing of frames. Numerical examples and explanations of mathematical methods are included in Appendices.