Aerodynamic characteristics of a tandem wing configuration of a Mach number of 0.30

An investigation was conducted to determine the aerodynamic characteristics of a tandem wing configuration. The configuration had a low forward mounted sweptback wing and a high rear mounted sweptforward wing jointed at the wing tip by an end plate. The investigation was conducted at a Mach number of 0.30 at angles of attack up to 20 deg. A comparison of the experimentally determined drag due to lift characteristics with theoretical estimates is also included

Effect of wing pivot location on longitudinal aerodynamic characteristics of a variable sweep wing having an M planform

Wing pivot location effect on longitudinal aerodynamic characteristics of variable sweep wing having M planfor

Non-analytic curvature contributions to solvation free energies: influence of drying

We investigate the solvation of a hard spherical cavity, of radius $R$, immersed in a fluid for which the interparticle forces are short ranged. For thermodynamic states lying close to the liquid binodal, where the chemical potential deviation $\delta \mu\equiv \mu - \mu_{co}(T)$ is very small and positive, complete wetting by gas (drying) occurs and two regimes of interfacial behavior can be identified. These are characterized by the length scale $R_c=2 \gamma_{gl}^\infty/(\Delta \rho \delta \mu)$, where $\gamma_{gl}^\infty$ is the planar gas-liquid surface tension and $\Delta \rho$ is the difference in coexisting densities at temperature $T$. For $R>R_c$, the interfacial free energy and the density profile of the fluid near the hard wall can be expanded in powers of the curvature $R^{-1}$, in keeping with the analysis of Stillinger and Cotter, J. Chem. Phys. {\bf 55}, 3449 (1971). In the other regime, $R<R_c$, the interfacial free energy and its derivatives acquire terms depending on $\ln R$. Since $R_c^{-1}$ can be made arbitrarily small this implies non-analytic behavior, as $R^{-1}\to 0$, of the work of formation of a hard spherical cavity and of the Gibbs adsorption and the fluid density at contact with the wall. Our analysis, which is based on an effective interfacial Hamiltonian combined with exact statistical mechanical sum rules, is confirmed fully by the results of microscopic density functional calculations for a square-well fluid.Comment: 17 pages, 3 figures; accepted for publication in J. Chem. Phy

GREEK LYRIC IMAGERY: PROBLEMS OF INTERPRETATION

1. Introduction Any study of the imagery in ancient Greek lyric poetry is faced with a number of problems ranging from difficult to insurmountable. These problems arise mainly from the fragmented state of both the lyric texts themselves and the ancient responses to the imagery preserved for us in the testimonia. However, this state of the primary material should not deter us from attempting controlled analysis of this important aspect of ancient Greek poetry (as it is of all poetry). Latacz has identified an uncertainty, an open-endedness in studies on Greek lyric. "Wir arbeiten also im Grunde mit Hypothesen" (1986:39). There is a natural reluctance to offer lyric theory. "Wie frtihgriechische Lyrik konstituiert und als System strukturiert ist, wie sie im Einzelfall entsteht, wie sie 'funktioniert' hat, wodurch und wie sie wirken wollte und gewirkt hat-, diese (synchroniese) Analyse hat die Lyrikforschung bisher allenfalls ansatzweise in den Blick genommen; eine Poetik der frtihgriechischen Lyrik (ebenso iibrigens wie des Epos) steht noch aus" (1986:42). In spite of these obstacles, interpretation is required, even if it is to be characterised by "legitimer Subjektivitat" (1986:37). Although it is impossible to recreate the impact of the imagery on the contemporary (or "target") Greek audiences, a first, tentative step can be taken towards the formulation of some kind of theory of reception by analysing the way in which the ancient writers represented in the surviving testimonia dealt with images in the lyric (i.e. melic) poetry of ancient Greece

THE CLASSICAL ASSOCIATION OF SOUTH AFRICA: FEBRUARY 1983 – JANUARY 1985

Previous articles on the history of the Classical Association of South Africa, based on archival material, covered the period from 1908 to 1983.  The present instalment takes this history to the beginning of 1985

THE CLASSICAL ASSOCIATION OF SOUTH AFRICA: FEBRUARY 1981 – JANUARY 1983

This article continues the history of the Classical Association of South Africa as recorded in the archives of the Association.Since the publication of the previous accounts, an important study has appeared, which reconstructs some of the political, social and cultural contexts in which the activities of the Association, as reflected in my archival reports, were imbedded. I refer to Michael Lambert’s book, The Classics and South African Identities (2011). Lambert’s work now adds flesh on to the bare bones of the archival material

The Classical Association of South Africa : February 1983 – January 1985

Abstract: Please refer to full text to view abstrac

Yellow Dwarf, a virus disease of Onions, and its control

Yellow dwarf of onions is a transmissible virus disease, of the mosaic group. The virus overwinters in the infected onion bulbs and in volunteer onion plants that live over winter in the fields. It probably is neither seed nor soil borne. Yellow dwarf symptoms are characterized by yellowing and crinkling of the leaves, which become more or less flat and droop over in the advanced stages. Flower stalks of infected mother on ion plants become yellow, twist, and curl and are shorter than normal plants. Masking of yellow dwarf symptoms occurs quite commonly in infected onion plants, and these plants are a source of inoculum for infecting healthy plants; bulbs from the plants masking symptoms when regrown produce infected plants that show disease symptoms. Plants grown from infected onion sets and those that become infected early in the growing season produce under-developed bulbs of little commercial value. Onion plants having masked infection throughout their growth period produce apparently normal plants and yields. Infected mother onion plants produce normal seed, but the seed yield is about 30 percent less than from healthy plants. Yellow Dwarf is transmissible by artificial inoculation and insect vectors. By artificial inoculations the incubation period is usually about 10 days. Onion bulbs hypodermically inoculated with juice extracted from the fleshy and dry scale leaves of infected onion bulbs failed to show infection. Inoculations made during retarded growth periods either fail to infect the plants or the symptoms are not manifested during the current growth period. Signs of the disease appear when the bulbs of such infected plants are regrown. The virus extracted from yellow dwarf infected onion leaves that mask the symptoms is infective. Yellow dwarf virus was transmitted under controlled conditions by the bean aphid (Aphis rumiscis Linn.), corn leaf aphid (Aphis maidis Fitch.), and the apple grain aphid (Rhopalosiphum prunifoliae Fitch). The yellow dwarf virus was inactivated when the viriferous juice was stored in vitro at 29° C. for a period of 112 hours. When infected onion leaves were stored in the open, at 29° C. for 100 hours, juice extracted from the leaves was non-infective. The infectivity of the virus was only slightly retarded when viriferous juice was heated 10 minutes at 70° C. At 75° C. for 10 minutes, 55 percent of the original virulence of the virus was lost. At 80° C. for 10 minutes, the virus was inactivated. With 10-minute exposures the critical thermal point for the yellow dwarf virus lies between 75 and 80° C. Exposures as low as -14° C. for 6 hours failed to inactivate yellow dwarf virus. Inoculations with dilutions of 1-10,240 and above failed to infect any of the onion plants. Yellow dwarf virus inoculated into Chinese sacred lily (Narcissus tazetta L.) bulbs, Jonquil (Narcissus jonquilla L.) bulbs and shallots (Allium sativum L.) visibly infected 60, 30 and 90 percent of the plants, respectively. Inoculations with other plant viruses, including mosaic of Chinese sacred lily (Narcissus tazetta L.) and Jonquil (Narcissus jonquilla L.) failed to infect onion plants. Only one (Riverside Sweet Spanish) of thirty-six onion varieties tested seemed to be markedly resistant. The combined effect of indexing all growing stocks of onion bulbs, producing the planting stock of bulbs in areas free from yellow dwarf and roguing out the infected volunteer onions in the fields reduced the percentage of yellow dwarf infection in the district from 40 percent in 1928 to a trace in 1933 and 1934

ASPECTS OF THE ANCIENT GREEK SYMPOSION

Introduction For the duration of its history in the period when Greece was still a predominantly oral culture, deep into the 4th century BC, the symposion was one of the most important places where citizens, young and old, were prepared for their civic roles in the city-state. At the same time it provided the context in which poetry, as one of the media in the educational process, was created, communicated and preserved. Its religious-philosophical character and its secure and frank environment provided a context conducive to intellectual debate, friendly and genial association, and the uninhibited enjoyment of sensual pleasures