On the output of acoustical sources

Contents: (1) a theoretical basis for local power calculation; (2) source radiation in the presence of a half-plane; (3) radiation from a line source near an edge at which a Kutta condition holds; (4) radiation by a point source above a plane independence boundary; and (5) power output of a point source in a uniform flow

A note on sound radiation into a uniformly flowing fluid

Sound radiation generated by mechanical or vibratory source arrangements and, in some instances of planar or piston types, encompasses all magnitudes of the wavelength or frequency as well as disposition of the observation site. The comparative increase in average total radiated power from infinitesimally small or point sources of periodic strength, on passing from rest to steady rectilinear motion, depends only on Mach number in the noncompact case; and a formally analogous rise in output is linked, to the presence of a steady parallel flow past a rigid plane wall in which a compact circular piston executes normal oscillations. The perspective of effects connected with such a background is flow is widened by regard for an elongated or strip piston, which prototype permits a straightforward and general analysis

Numerical nonlinear inelastic analysis of stiffened shells of revolution. Volume 2: User's manual for STARS-2P digital computer program

The information necessary for application of the STARS-2P (shell theory automated for rotational structures-2(plasticity)) program is presented. This addition to the STARS system of programs retains the basic fractures characteristic of the system. For vol. 1, see N75-27419

Numerical nonlinear inelastic analysis of stiffened shells of revolution. Volume 1: Theory manual for STARS-2P digital computer program

The theoretical analysis background for the STARS-2P nonlinear inelastic program is discussed. The theory involved is amenable for the analysis of large deflection inelastic behavior in axisymmetric shells of revolution subjected to axisymmetric loadings. The analysis is capable of considering such effects as those involved in nonproportional and cyclic loading conditions. The following are also discussed: orthotropic nonlinear kinematic hardening theory; shell wall cross sections and discrete ring stiffeners; the coupled axisymmetric large deflection elasto-plastic torsion problem; and the provision for the inelastic treatment of smeared stiffeners, isogrid, and waffle wall constructions

Evolving macro-actions for planning

Domain re-engineering through macro-actions (i.e. macros) provides one potential avenue for research into learning for planning. However, most existing work learns macros that are reusable plan fragments and so observable from planner behaviours online or plan characteristics offline. Also, there are learning methods that learn macros from domain analysis. Nevertheless, most of these methods explore restricted macro spaces and exploit specific features of planners or domains. But, the learning examples, especially that are used to acquire previous experiences, might not cover many aspects of the system, or might not always reflect that better choices have been made during the search. Moreover, any specific properties are not likely to be common with many planners or domains. This paper presents an offline evolutionary method that learns macros for arbitrary planners and domains. Our method explores a wider macro space and learns macros that are somehow not observable from the examples. Our method also represents a generalised macro learning framework as it does not discover or utilise any specific structural properties of planners or domains

Properties of developmental gene regulatory networks

The modular components, or subcircuits, of developmental gene regulatory networks (GRNs) execute specific developmental functions, such as the specification of cell identity. We survey examples of such subcircuits and relate their structures to corresponding developmental functions. These relations transcend organisms and genes, as illustrated by the similar structures of the subcircuits controlling the specification of the mesectoderm in the Drosophila embryo and the endomesoderm in the sea urchin, even though the respective subcircuits are composed of nonorthologous regulatory genes

Finite element analysis of structures in the plastic range

Finite element analysis of structures in plastic rang

Sectors May Use Multiple Technologies Simultaneously - The Rectangular Choice-of-Technology Model with Binding Factor Constraints

We develop the rectangular choice-of-technology model with factor constraints, or RCOT, for analysis of the economy of a single region, or of multiple regions in the context of a model of the world economy. RCOT allows for one or more sectors to operate more than one technology simultaneously, using the relatively lowest-cost one first and adding another if and when the preceding one encounters a binding factor constraint. The model is motivated by the evident fact that oil wells and mineral deposits of different qualities may be exploited simultaneously, as may the use of both primary and recycled sources for the same materials. RCOT generalizes Carter’s choice-of-technology model, which allowed one of two choices to all sectors, for up to q choices and adds the factor constraints that allow several alternatives to operate simultaneously. The Appendix gives a numerical example.

Sectors May Use Multiple Technologies Simultaneously: The Rectangular Choice-of-Technology Model with Binding Factor Constraints (Revised)

We develop the rectangular choice-of-technology model with factor constraints, or RCOT, a linear programming input-output model for analysis of the economy of a single region. It allows for one or more sectors to operate more than one technology simultaneously, with the relatively lowest-cost one supplemented by others if it encounters a binding factor constraint. The RCOT model solves for sector outputs, goods prices that are set by the highest-cost technologies in use, and scarcity rents that correspond to binding factor constraints experienced by the lower-cost technologies. The model is motivated by the fact that mineral deposits of different qualities may be exploited simultaneously, as may primary and recycled sources for the same materials or irrigated and rainfed techniques for producing the same crop. RCOT generalizes Carter’s square choice-of-technology model, in particular adding the factor constraints that allow several alternatives to operate simultaneously. The Appendix gives a numerical example.

Human Ecology: Industrial Ecology

Industrial Ecology aims to inform decision making about the environmental impacts of industrial production processes by tracking and analyzing resource use and flows of industrial products, consumer products and wastes. Quantifying the patterns of use of materials and energy in different societies is one area of research in Industrial Ecology. An extensive literature is devoted in particular to Material Flow Analysis (MFA), the collection of data describing the flows of specific materials from sources to sinks within some portion of the global industrial system. Industrial Ecologists are also concerned with the system-wide environmental impacts associated with products. Design for the Environment involves the design or redesign of specific products so as to reduce their impacts, while Life Cycle Analysis (LCA) quantifies resource use and emissions per unit of product from material extraction to the eventual disposal of the product. The LCA community has created a significant body of best-practice methods and shared data and increasingly incorporates their analyses within input-output models of entire economies to capture that portion of the impact that would otherwise be overlooked. Input-output models, often incorporating both MFA and LCA data, analyze the effects on the environment of alternative consumption and production decisions. Industrial Ecology makes use of this array of top-down and bottom-up approaches, all of which are grounded in its origins in the ecology of the industrial system.