From Orbit to Ocean—Fixing Southeast Asia’s Remote-Sensing Blind Spots

Improving maritime domain awareness (MDA) in Southeast Asia is critical not only for regional states but for the national-security interests of the United States. MDA in the coming decades will be dominated by cheaper, more-efficient remote-sensing tools, and the United States and other outside parties should shift toward introducing partners to the booming private-sector offerings in remote sensing

Energy Storage Capacity Of Reversible Liquid‐phase Diels Alder Reaction Between Maleic Anhydride And 2‐methyl Furan

Calorimetry was used to determine the heat of reaction and equilibrium constant at 318 K for the reaction between maleic anhydride (A) and 2‐methyl furan (B). The values were −60 kJ/gmol and 614 cm3/gmol, respectively. The motivation for this work was to find a single phase‐reacting system that could be used to store solar energy. Thus, the energy storage capacity was calculated for a mixture of A and B, both initially at 7 kmol/m3, in dioxane. The maximum apparent heat capacity of 7.37 J/cm3·K occurred at 334 K. This maximum value is 76% higher than the heat capacity of pure water. Copyright © 1983 American Institute of Chemical Engineer

Vapor-Liquid Equilibrium Data For The NH3-H2O System And Its Description With A Modified Cubic Equation Of State

New pressure-temperature-overall composition vapor-liquid equilibrium (VLE) data are reported for the ammonia-water system at five temperatures between 20 and 140 °C and up to 500 pela. These data have been converted to T-P-x data, and vapor-phase compositions have been calculated by means of a Rediich-Kwong equation of state modified to Include Peneloux\u27s volume translation and a density-dependent mixing rule. In order to achieve agreement of calculated vapor-phase compositions with previous literature results, H was necessary to use different kij values In the vapor and liquid phases. © 1991, American Chemical Society. All rights reserved

Reliability Testing of AlGaN/GaN HEMTs Under Multiple Stressors

We performed an experiment on AlGaN/GaN HEMTs with high voltage and high power as stressors. We found that devices tested under high power generally degraded more than those tested under high voltage. In particular, the high-voltage-tested devices did not degrade significantly as suggested by some papers in the literature. The same papers in the literature also suggest that high voltages cause cracks and pits. However, the high-voltage-tested devices in this study do not exhibit cracks or pits in TEM images, while the high-power-tested devices exhibit pits

Numerical framework for transcritical real-fluid reacting flow simulations using the flamelet progress variable approach

An extension to the classical FPV model is developed for transcritical real-fluid combustion simulations in the context of finite volume, fully compressible, explicit solvers. A double-flux model is developed for transcritical flows to eliminate the spurious pressure oscillations. A hybrid scheme with entropy-stable flux correction is formulated to robustly represent large density ratios. The thermodynamics for ideal-gas values is modeled by a linearized specific heat ratio model. Parameters needed for the cubic EoS are pre-tabulated for the evaluation of departure functions and a quadratic expression is used to recover the attraction parameter. The novelty of the proposed approach lies in the ability to account for pressure and temperature variations from the baseline table. Cryogenic LOX/GH2 mixing and reacting cases are performed to demonstrate the capability of the proposed approach in multidimensional simulations. The proposed combustion model and numerical schemes are directly applicable for LES simulations of real applications under transcritical conditions.Comment: 55th AIAA Aerospace Sciences Meeting, Dallas, T

Product Distributions In The CO2-NH3-H2O System From Liquid Conductivity Measurements

The objective of this work was to illustrate how liquid conductivity measurements could be used to provide information about the extent of ionization and the amounts of the various ionic products that are formed in the liquid phase in the CO2-NH3-H2O system. To accomplish this, pressures and liquid-phase conductivities for the CO2-NH3-H2O system were measured at 25 °C and over a range of pressures and concentrations. In order to acquire the desired information from bulk conductivity measurements, calibration curves were established from measurements with several potassium salts. These curves, in conjunction with the experimental conductivity, allowed the (approximate) determination of both the concentration of the NH4+ ion and the distribution of CO2 between singly and doubly charged ions. Comparison to the predictions of two existing models for the CO2-NH3-H2O system showed that these models underpredicted the concentration of the ammonium ion. This suggests that correct predictions of the vapor-phase compositions and pressures by a solution model do not guarantee that the description of the liquid phase is correct. © 1992, American Chemical Society. All rights reserved