Development and validation of a general purpose linearization program for rigid aircraft models

A FORTRAN program that provides the user with a powerful and flexible tool for the linearization of aircraft models is discussed. The program LINEAR numerically determines a linear systems model using nonlinear equations of motion and a user-supplied, nonlinear aerodynamic model. The system model determined by LINEAR consists of matrices for both the state and observation equations. The program has been designed to allow easy selection and definition of the state, control, and observation variables to be used in a particular model. Also, included in the report is a comparison of linear and nonlinear models for a high performance aircraft

Kinetics of the exchange reaction between two oxidation states of cerium

The radioactive cerium exchange reaction was employed to study the electron transfer reaction in perchloric acid between ceriurm (III) and cerium (IV). In particular, the study was carried out to extend previous investigations, to elucidate further, if possible, the nature of the ionic species that exist in perchloric acid solution, and to examine the various factors determining the rate of exchange

Ion mobilities in fused salts

The transport numbers of the chloride ion in the pure molten alkaline earth chlorides have been determined. A modified Stokes\u27 law was applied to the motion of the individual ions. Application of the assumptions made in invoking this law gave a qualitative estimate as to the degree of association in MgCl 2, CaCl2, SrCl2, BaCl2, ZnCl2, and PbCl2 • Several trends were observed which were consistent with the chemical properties of the salts studied

Transport numbers and ion mobilities in the fused salt KCl-PbCl2

Values of ionic transport numbers and ionic mobilities were determined for the fused system KCl-PbCl2. Cation transport numbers of 0.24 (525°C) and 0.78 (850°C) were found for PbCl2 and KCl, respectively. In each mixture studied t- deviated positively and both t+ and t++ deviated negatively from linearity when plotted against equivalent fraction. The initial very rapid depression of total equivalent conductance from that of pure KCl, caused by addition of small amounts of PbCl2, was found to be due to the depression of the ionic conductance of K+ rather than complexing between Pb++ and Cl- as had been previously supposed. Values of 0 were comp~red with those in the system LiCl-PbCl2, calculated from available literature data

Complex metal halides in fused alkali nitrates

The results of this investigation have provided additional information by chemical methods of the extent of association in fused salts. Association effects observed in solubility and rate studies in fused alkali nitrate are shown to be consistent with the assumption that complex ions such as those existing in aqueous solutions are formed between metal ions and halide ions. In addition, the rate studies suggest a mechanism for a reaction involving dichromate and nitrate ions in a fused alkali nitrate solvent

Ionic mobilities in selected fused salt systems

Transport numbers were determined in the pure fused salts, LiNO3, NaNO3, KNO3, and AgNO3 by measuring the volume changes of the material in the electrode compartments which took place during electrolysis of the melt. Transport numbers in the two binary fused salt systems AgNO3-NaNO3 and AgNO3- KNO3 were determined by measuring the volume changes accompanying electrolysis and the concentration changes accompanying electrolysis

Surface tensions of some binary fused salt systems

The surface tensions of eight pure fused salts and nine binary mixtures were measured by the maximum bubble pressure method. Surface tension showed essentially linear variation with temperature in all cases

Results of the August 1977 Soviet and American meterological rocketsonde intercomparison held at Wallops Island, Virginia

A coordinated program of rocketsonde investigations along about 60 deg E and 70 deg W between the United States and U.S.S.R. is discussed. The rocketsonde instruments used by the U.S. and U.S.S.R. were compared and the results are presented. The U.S. Super Loki Datasonde and the U.S.S.R. M100B rocketsonde are discussed. Results indicate that the U.S/U.S.S.R. rocketsonde measurement agreement improved since the 1973 intercomparisons. It was learned that the mean of the differences of the temperatures compare to within 6 C at about 60 km and to within 2 C near 50 km. Wind measurements were also found to agree

Study of effects of fuel properties in turbine-powered business aircraft

Increased interest in research and technology concerning aviation turbine fuels and their properties was prompted by recent changes in the supply and demand situation of these fuels. The most obvious change is the rapid increase in fuel price. For commercial airplanes, fuel costs now approach 50 percent of the direct operating costs. In addition, there were occasional local supply disruptions and gradual shifts in delivered values of certain fuel properties. Dwindling petroleum reserves and the politically sensitive nature of the major world suppliers make the continuation of these trends likely. A summary of the principal findings, and conclusions are presented. Much of the material, especially the tables and graphs, is considered in greater detail later. The economic analysis and examination of operational considerations are described. Because some of the assumptions on which the economic analysis is founded are not easily verified, the sensitivity of the analysis to alternates for these assumptions is examined. The data base on which the analyses are founded is defined in a set of appendices

Giant Electroresistance in Ferroelectric Tunnel Junctions

The interplay between the electron transport in metal/ferroelectric/metal junctions with ultrathin ferroelectric barriers and the polarization state of a barrier is investigated. Using a model which takes into account screening of polarization charges in metallic electrodes and direct quantum tunneling across a ferroelectric barrier we calculate the change in the tunneling conductance associated with the polarization switching. We find the conductance change of a few orders of magnitude for metallic electrodes with significantly different screening lengths. This giant electroresistance effect is the consequence of a different potential profile seen by transport electrons for the two opposite polarization orientations.Comment: 4 page