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Cold Flow Calorimeter

This apparatus can measure a rapidly varying heat-transfer coefficient. The cold flow calorimeter is an apparatus for measuring a possibly rapidly varying heat-transfer coefficient on a surface. The cold flow calorimeter includes (1) a small strain gauge bonded to a small, thin steel shim that is placed on the surface of interest and (2) a circuit that controls the electric power supplied to the strain gauge to keep the strain-gauge grid at a constant temperature [e.g., 150 °F (≈66 °C)]. The instantaneous value of the heattransfer coefficient is deduced from the instantaneous power required to maintain the constant temperature. The heat-transfer coefficient measurable by use of this apparatus can range from values characteristic of natural convection to values as large as about 1,000 Btu/(ft·h·°R) [≈1.7 kW/(m·K).

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Electrochemical Systems Generate Ozone and Ozonated Water

The only inputs needed are electric energy and mildly pressurized water. Improved electrochemical systems for generating ozone (in gaseous form and/or dissolved in water) have been invented for use in disinfection and in industrial processes in which the unique, highly oxidizing chemical properties of ozone are needed. More accurately, these systems generate oxygen along with high (relative to prior systems) concentrations of ozone and, optionally, with hydrogen as a byproduct. These systems contain no pumps and very few moving or wearing components, and the only inputs needed to operate these systems are electric energy and water supplied at mild pressure. Moreover, these systems can readily be designed and constructed on any scale (e.g., from research laboratory to industrial) to suit a wide variety of applications.

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Solar Simulator for a Portable Solar-Absorptance Instrument

The principal advantages are portability and accurate normalized AM0 spectrum. A special-purpose solar simulator includes (1) a tungsten lamp that serves as a gray-body radiator with a temperature of 3,200 K and (2) a mosaic of filters such that the filtered lamp output has the same normalized spectral irradiance as that of sunlight outside the atmosphere of the Earth. This solar simulator is intended for use as the illuminator in a portable instrument that measures solar absorptances and total emittances of samples of materials.

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Portable Instrument Detects Very Dilute Airborne Organics

This instrument offers an attractive alternative to GC/MS. A small, lightweight, low-power instrument, denoted a proton-transferreaction/ ion-mobility spectrometer (PTR-IMS) has been developed for detecting airborne organic compounds at concentrations in the sub-parts-per-billion range. Instruments like this one could be used on distant planets (such as Mars) to search for trace organic compounds indicative of life as well as numerous potential terrestrial uses: A few examples include medical applications (e.g., analyzing human breath to detect compounds associated with certain deadly diseases such as lung cancer and cirrhosis of the liver), lawenforcement applications (detecting airborne traces of explosives and drugs), environmental monitoring (detecting airborne pollutants and toxins), and military applications (detecting chemical warfare agents).

Posted in: Briefs, TSP, Physical Sciences

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Quantum Mechanics of Harmonic Oscillator in External Fields

A report presents a theoretical study of a harmonic oscillator in homogeneous or nonhomogeneous externally applied electric and/or gravitational fields. The standard quantum-mechanical formalism for a simple harmonic oscillator, starting with the Hamiltonian and the associated creation and annihilation operators, is modified to incorporate the additional terms representing the external fields. The correspondingly modified solutions of the Schroedinger equation are derived.

Posted in: Briefs, TSP, Physical Sciences

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Effect of Gravitation on Noninteracting Trapped Fermions

A report presents a theoretical study of the thermodynamics of an ultralow-temperature gas of fermions that interact with a gravitational field and with an externally imposed trapping potential but not with each other. The gravitational field is taken to define the z axis and the trapping potential to be of the form (m/2) (ωxx2+ωyy2+ωzz2), where m is the mass of a fermion; x, y, and z are Cartesian coordinates originating at the center of the trap; and the ω values denote effective harmonic- oscillator angular frequencies with respect to motion along the respective coordinate axes. The single-particle energy is found from the solution of the time-dependent Schroedinger equation for a Hamiltonian that includes kinetic energy plus the gravitational and trapping potentials. The equation for the single-particle energy is combined with Fermi statistics to obtain equations for the chemical potential, internal energy, and specific heat of the gas; the number of trapped fermions; and the spatial distribution of fermions at zero temperature. The equations reveal the ways in which the Fermi energy, the specific heat, and the shape of the Fermion cloud are affected by the gravitational field and the anisotropy of the trapping field.

Posted in: Briefs, TSP, Physical Sciences

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New Technique Improves Cirrus Cloud Characterization

Radiometric measurements at submillimeter-wavelength accurately characterize cirrus cloud properties. A new technique for retrieving cirrus properties from radiometric measurements at submillimeter wavelengths has been developed. The technique can accurately measure the amount of ice present in cirrus clouds, determine the median crystal size, and constrain crystal shape. The retrieval algorithm improves upon prior algorithms by also retrieving middle and upper tropospheric water-vapor profiles in concert with cloud properties. This joint-analysis method corrects for retrieval errors introduced by water vapor in and near the cloud.

Posted in: Briefs, TSP, Physical Sciences

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