The Expected Growth of Population in the United States

Author Institution: Scripps Foundation for Research in Population Problems, Miami University, Oxford, Ohi

Crash-Fire Protection System for T-56 Turbopropeller Engine Using Water as Cooling and Inerting Agent

A crash-fire protection system to suppress the ignition of crash-spilled fuel that may be ingested by a T-56 turbopropeller engine is described. This system includes means for rapidly extinguishing the combustor flame and means for cooling and inerting with water the hot engine parts likely to ignite engine-ingested fuel. Combustion-chamber flames were extinguished in 0.07 second at the engine fuel manifold. Hot engine parts were inerted and cooled by 52 pounds of water discharged at ten engine stations. Performance trials of the crash-fire prevention system were conducted by bringing the engine up to takeoff temperature, stopping the normal fuel flow to the engine, starting the water discharge, and then spraying fuel into the engine to simulate crash-ingested fuel. No fires occurred during these trials, although fuel was sprayed into the engine from 0.3 second to 15 minutes after actuating the crash-fire protection system

Electron Self-Trapping in Ge\u3csub\u3e2\u3c/sub\u3e Se\u3csub\u3e3\u3c/sub\u3e and Its Role in Ag and Sn Incorporation

We present a set of density functional theory (DFT) calculations on the electronic structure of Ag and Sn in Ge2 Se3 in a periodic model. We show that electron self-trapping is a persistent feature in the presence of many defects. Ag and Sn autoionize upon entering Ge2 Se3 becoming Ag+ and Sn2+ , respectively, and the freed electrons self trap at the lowest energy site. Both Ag and Sn can substitute for Ge, and we present formation energies as a function of Fermi level that show that Sn can substantially alter the incorporation of Ag into the Ge2Se3 network

Horizontal transfer of methoprene in Tribolium castaneum

Aerosol applications of reduced risk insecticides such as pyrethrins, pyrethroids, and insect growth regulators are becoming more commonly used to manage stored-product insects in food facilities. However, these applications have a limited ability to penetrate into hidden refugia, where the majority of the pest population is located. Horizontal transfer of insecticides could occur as individuals directly treated or exposed to treated surfaces move into hidden refugia and encounter untreated individuals. In this series of studies, the potential for horizontal transfer of methoprene from treated Tribolium castaneum , the red flour beetle, to untreated individuals was evaluated. Adding larvae, pupae, or adults treated with methoprene to flour patches with untreated T. castaneum larvae, resulted in increased pupa and adult deformities and higher numbers of dead focal individuals, which suggests the potential for this mechanism. The transfer mechanism might be flour substrate contamination, transfer during contact of individuals, and/or cannibalism of individuals exposed to insecticides. Experiments focused on isolating the impact of contact and cannibalism on horizontal transfer did not detect a significant increase in mortality. Experiments focused on flour substrate contamination resulted in decreased adult emergence as well as lower survival, and higher rates of deformities. These findings suggest that substrate contamination is the more likely mechanism for horizontal transfer, and although horizontal transfer can occur, the impact of this process on populations needs further evaluation. Keywords: Red flour beetle, Tribolium castaneum, Methoprene, Horizontal transfe

Physiology

Contains reports on three research projects

The Presence of Flour Affects the Efficacy of Aerosolized Insecticides used to Treat the Red Flour Beetle, Tribolium castaneum

Experiments were conducted in tightly sealed pilot scale warehouses to assess the efficacy of common aerosolized insecticides on all life stages of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) when exposed in dishes containing 0 to 2 g of wheat flour either under pallets or out in the open. Petri dishes containing 0, 0.1, 1, or 2 g of flour were prepared with 25 eggs, 3rd instars, pupae, or adults and then immediately treated with aerosolized solvent, Pyrethrins, or esfenvalerate. Twenty-four h after insecticide exposure, the dishes were brought to the laboratory and placed in a growth chamber and held for a 3 day moribund (knockdown) assessment and a 21 day mortality assessment. Mortality in untreated controls was generally less than 10%, with the exception of the 21 day counts of adults and eggs. Solvent-treated replications followed similar trends, except that additional mortality was observed in exposed larvae and pupae. In the insecticide-treated dishes, mortality of T. castaneum provisioned with flour generally showed a linear decrease with increasing flour deposits. Regardless of life stage, mortality did not exceed 60% when individuals were exposed in petri dishes containing 2 g of flour. Exposure location also made a significant difference in observed mortality. While mortality never exceeded 75% in dishes positioned under pallets, there was never less than 80% mortality in dishes exposed in the open. Although there was a perceptible increase in mortality with esfenvalerate compared to Pyrethrins, these differences were considerably less than the variation observed among flour deposits. The study suggests that sanitation and preparation prior to aerosol insecticide treatments were more important than choice of a particular insecticide

Chronicles of Oklahoma

Article describes the journey and works of James Otto Lewis, an official artist who joined the commissioners of the Bureau of Indian Affairs to councils and treaty signings and documented the events. His collection of portraits of tribe chiefs is included

Physiology

Contains reports on four research projects

Report of the Advisory Committee in Seismology

The Advisory Committee in Seismology has pleasure in reporting the continued progress of its study of California earth movements during the year 1924-1925 without essential change of plan. A considerable amount of geologic work in the study of fault zones has been done during the year in the Mojave Desert and in Death Valley, the system of primary triangulation for the detection and measurement of horizontal displacements has progressed rapidly and effectively, and the development of suitable instruments for determining the two horizontal components of local earth movements has progressed to completion. Ground for a new laboratory has been purchased by the California Institute of Technology and the construction of the central station laboratory building upon it has been begun. The laboratory is expected to be occupied by Mr. H. O. Wood, Research Associate in Seismology, and his associates, about January 1, 1926. It is hoped that additional stations will also be occupied before the close of the present calendar year (1925), and that actual work in what has been happily termed the seismologic triangulation of California will be successfully inaugurated