Flow and fracture of ice and ice mixtures

Frozen volatiles make up an important volume fraction of the low density moons of the outer solar system. Understanding the tectonic history of the surfaces of these moons, as well as the evolution of their interiors, requires knowledge of the mechanical strength of these icy materials under the appropriate planetary conditions (temperature, hydrostatic pressure, strain rate). Ongoing lab research is being conducted to measure mechanical properties of several different ices under conditions that faithfully reproduce condition both at the moons' surfaces (generally low temperature, to about 100 K, and low pressures) and in the deep interiors (warmer temperatures, pressures to thousands of atmospheres). Recent progress is reported in two different phases of the work: rheology of ices in the NH3-H2O system at temperatures and strain rates lower than ever before explored, with application to the ammonia-rich moons of Saturn and Uranus; and the water ice I yields II phase transformation, which not only applies directly to process deep in the interiors of Ganymede and Callisto, but holds implications for deep terrestrial earthquakes as well

Linguistic Reflection in Java

Reflective systems allow their own structures to be altered from within. Here we are concerned with a style of reflection, called linguistic reflection, which is the ability of a running program to generate new program fragments and to integrate these into its own execution. In particular we describe how this kind of reflection may be provided in the compiler-based, strongly typed object-oriented programming language Java. The advantages of the programming technique include attaining high levels of genericity and accommodating system evolution. These advantages are illustrated by an example taken from persistent programming which shows how linguistic reflection allows functionality (program code) to be generated on demand (Just-In-Time) from a generic specification and integrated into the evolving running program. The technique is evaluated against alternative implementation approaches with respect to efficiency, safety and ease of use.Comment: 25 pages. Source code for examples at http://www-ppg.dcs.st-and.ac.uk/Java/ReflectionExample/ Dynamic compilation package at http://www-ppg.dcs.st-and.ac.uk/Java/DynamicCompilation

Capacitive sensor technology for polyethylene pipe fault detection

This work develops a Finite Element Analysis simulation to determine if capacitive sensors can be used to detect defects in polyethylene gas distribution pipes. Currently, there is no in ground detection system to find the defect. Catastrophic results can occur if gas leaks are present and ignite. Finite Element Analysis (FEA) software will be used to simulate how different shapes and sizes of capacitive sensors affect the electric field, which affect capacitance when the dielectric of a material changes. An optimal electrode size and shape was chosen from these simulations, built, and tested at the Battelle Pipeline Safety Research & Development Program. The sensor was run through multiple tests on a thirteen foot long, six inch diameter polyethylene pipe with a half inch wall thickness where random defects were placed in the pipe. Upon completion of the test, the data was analyzed, and it determined that the capacitive sensor detected all known defects in the polyethylene pipe

Description of immature stages of Philolithus densicollis and Stenomorpha puncticollis with notes on their biology (Coleoptera, Tenebrionidae, Tentyriinae)

Mature larvae of the tribe Asidini are characterized by an unsclerotized body, dorsally concave mandibles with preapical gibbosity and submarginal setose area, granulate cranium, swollen preepipleurum, and huge granulate forelegs with contiguous coxae surrounded by an enlarged sternellum. The pygidial terminus is rounded in Philolithus densicollis (Horn) and bifurcate in Stenomorpha puncticollis (LeConte). First-instar larvae lack granules on cranium and forelegs, have 2 setae on the labrum, possess egg bursters, and are very similar in both species. Eggs are large, averaging 2.5 mm in length in P. densicollis and 3.1 mm in S. puncticollis. Pupae are not known. The two species are sympatric in eastern Washington state. Adults occur in autumn, living only one month. A female deposits about 1 egg per day. Eggs of P. densicollis hatch quickly and the first winter is passed in an early larval stage. Eggs of S. puncticollis apparently overwinter and hatch in early spring. The full life cycle probably takes two years. Cold temperature of the second winter breaks a developmental diapause and leads to adult eclosion the following autumn; S. puncticollis emerges somewhat later than P. densicollis. The prolonged immature phase as a subterranean scavenger is seen as a major adaptation to xeric environments

Creep of ice: Further studies

Detailed studies have been done of ice creep as related to the icy satellites, Ganymede and Callisto. Included were: (1) the flow of high-pressure water ices II, III, and V, and (2) frictional sliding of ice I sub h. Work was also begun on the study of the effects of impurities on the flow of ice. Test results are summarized

A COMPARISON OF DEMANDS FOR MEAT PRODUCTS IN THE PACIFIC RIM REGION

The Rotterdam model is used to obtain estimates of demand parameters for meat products in Taiwan, South Korea, and Japan. Unlike most previous studies of demand systems, the model takes into account simultaneous-equation bias which arises due to the endogeneity of total expenditure. Beef, pork, and chicken are separable from marine products for each Pacific Rim country. However, demand elasticities for beef, pork, and chicken are different among the various Pacific Rim nations. One may not then use the elasticity estimates of a particular country and apply them to other Pacific Rim markets.Demand and Price Analysis,

Modelling sound propagation in the ocean: A normal mode approach using finite elements

© 2019 Australian Acoustical Society Annual Conference, AAS 2018. All rights reserved. Modelling the propagation of sound waves in the ocean is challenging because one must account for spatial variation in properties of the fluid and in the ocean geometry, as well as couple the fluid to a seabed that supports both shear and compressional waves. This article presents a f inite element based approach to obtaining the eigenmodes for an axial uniform ocean waveguide. Once these modes have been computed, an orthogonality relation is used to compute the sound pressure field for ranges of up to 5 km. This approach avoids the traditional heavy computational expenditure associated with the finite element method, at least for a uniform waveguide. Furthermore, the numerical approach properly accounts for the depth dependent properties of the ocean, and couples the ocean to a full elastodynamic representation of the seabed, which supports both shear and compressional waves. This permits the implementation of the physically correct transverse boundary conditions, as well as the addition of a perfectly matched layer to enforce the correct boundary conditions at infinite depth in the seabed

L.—On the Neuroptera collected during the recent expedition of H.M.S. 'Challenger'

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XVI.— Descriptions of two new species of Eugaster (Hetrodidæ) from East Africa

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