The effect of monomolecular surface films on the microwave brightness temperature of the sea surface

Abstract

Airborne microwave radiometer measurements at 1·43 and 2·65 GHz over a sea surface covered with a monomolecular oleyl alcohol surface film and over adjacent slick sea surfaces are presented. The measurements show that at 2·65 GHz the brightness temperature T _B is not affected by the slick, while at 1·43 GHz it drops from 93 K to a minimum value of almost O K. This implies that at 1·43 GHz the emissivity of the slick-covered sea surface is extremely small, similar to a metallic layer, and that this resonant-type phenomenon is confined to a narrow frequency band of width δ?/ ?<0·6.

The theoretical implications of these experimental findings are discussed in the framework of the Debye relaxation theory of polar liquids. It is conjectured that a thin layer of water molecules polarized by the surface film gives rise to an anomalous dispersion, which causes the large decrease in brightness temperature at 1·43 GHz.

The modulus of the relative dielectric constant ε? is estimated to be ≥ 5·2 × 10^?4 and the thickness of the emitting layer ≤1·9 × 10^?4 m for 1·43 GHz. Furthermore, the film-induced surface activation energy is calculated to be 9·18 × 10^?21 J. These values seem reasonable in the light of the theories on the physicochemical structure of surface layers.     

The System Zirconia-Scandia

The system zirconia-scandia was investigated using X-ray diffraction analysis, differential thermal analysis, metallographic analysis, and melting point studies. Results reveal the monoclinic α₁ phase (0 to 2 mol% Sc₂O₃), the tetragonal α₂'phase (5 to 8% Sc₂O₃), the rhombohedral β phase (9 to 13% Sc₂O₃), the rhombohedral γ phase (15 to 23% Sc₂O₃), the rhombohedral δ phase (24 to 40% Sc₂O₃), and the cubic % phase (77.5 to 100% Sc₂O₃). The monoclinic α₁ phase and the tetragonal α₂'phase were found to transform to the tetragonal α₂ phase over a wide temperature range depending on composition. The β, γ, and α phases transformed to a cubic phase at temperatures of %600^%, 1100^%, and 1300^%C, respectively. A maximum melting point of %2870^%C was found at %10% Sc₂O₃ and a eutectic at %2400^%C at 55% Sc₂O₃.     

Dielectric Properties of Sintered Yttrium Oxide

Relaxation phenomena were observed in sintered Y₂O₃ at frequencies from 10⁻³ to 10⁵ Hz at 150°, 200°, 255°, 306°, and 357°C. The observed dispersion is predicted approximately by a theory requiring exponential decay of the polarization. The theory describing the larger lower-frequency relaxation should be based on an interfacial mechanism with an inter-granular region of higher conductivity. Electrode effects cannot be ruled out, however, on the basis of the present work. The most probable basis for the theory describing the smaller higher-frequency relaxation is defect-dipole polarization.     

The Svstern Zirconia-Hafnia

The ZrO₂-HfO₂ system was investigated by metallo-graphic, X-ray diffraction, and microprobe analysis using are-melted samples which had been annealed and quenched. The monoclinic-tetragonal inversion was investigated by DTA and high-temperature X-ray diffraction analysis. Results reveal that zirconia and hafnia are completely miscible in all proportions in the binary system. Within experimental error, the melting points of the compositions lie roughly on a straight line connecting the melting points of oxides. There is a continuous increase in the monoclinic-tetragonal inversion temperature as the composition moves from ZrO₂ to HfO₂. The lattice parameters of the monoclinic phase follow smooth curves which have a negative deviation from Vegard's law.     

A remote sensing study of a surface ship wake

Abstract

The turbulent wake of the USNS Hayes, a twin hulled ship, was imaged simultaneously by a thermal infrared scanner, an X-band coherent microwave radar and a 35 mm strip camera mounted in an NRL RP-3A aircraft. Thermal surface effects and centimetre-scale surface roughness characteristics were determined for both natural ship wakes and those treated with oleyl alcohol, an organic material which produced a monomolecular film on the surface of the turbulent wake. Extensive hydrographic, oceanographic and meteorological data were obtained during the surface wake study. The turbulent motions and the presence of the monomolecular film at the wake surface strongly influenced the centimetre-scale roughness. This influence appeared as a significant reduction in the microwave backscatter from the wake compared to the ambient surface. The persistence of this reduction in backscattered power increased when the film was present. Various computer codes were employed to analyse the digitized IR video data. They generated temperature contour plots and temperature profiles across the wake at various locations behind the ship. These computer plots along with the original 70 mm photographic representation of the data and the corresponding water temperature data indicated that all the wakes were significantly cooler than the surrounding ambient surface water. The thermal signatures of the wakes treated with the surface film were more persistent than the natural wakes and the coo! surface was maintained over a broader cross section of the treated wakes. These observations can be explained on the basis of changes in water surface properties, the ship wake hydrodynamics, wind stress considerations and surface film physics.     

PERFORMANCE CHARACTERISTICS AND FATTY ACID COMPOSITION OF PIGS FED A DIET WITH DOCOSAHEXAENOIC ACID

Market hogs were fed a ration from 22–42 days prior that contained the omega-3 fatty acid docosahexaenoic acid (DHA) supplemented at 0, 0.125 and 0.250 kg/pig in the form of the microalgae , Schizochythrum sp. There were no differences (P>0.05) between the average daily gain, feed consumption, or feed efficiency of the controls and those that received a DHA supplementation. Of the 21 fatty acids analyzed, the concentration of only five were affected by DHA supplementation. Muscles from the ham, loin, and shoulder of pigs that received 0.250 kg of DHA contained more eicosapentaenoate, docosahexaenoate, and docosapentaenoate n-6 and n-3 than either the controls or those that received 0.125 kg. Supplementation of DHA in the ration at 0.125 kg caused an elevation of docosapentaenoate n-6 and docosahexaenoate. These data suggest that addition of DHA to the diet can elevate the amount of this omega-3 fatty acid in pork with potential health benefits to consumers.     

The supplier view

The major suppliers of goods and services to the dairy industry are identified. The commercial relationships arising in each sector of supply are considered and comparisons are made between monopolistic and competitive sources. Consideration is given to the scope of suppliers' responsibilities in terms of design, development and collaborative ventures.     

New Finishes for Terylene and Terylene Blend Fabrics

Problems arising from the hydrophobic nature of Terylene (ICI) are discussed, viz. the generation of a static charge and consequent soiling. The first successful attempt to overcome these problems by modifying the fibre surface was a treatment with sodium polyglycollate, but this process was unsuitable for commercial use. A new finishing agent, Permalose T, which confers antistatic and improved anti–soiling properties was therefore developed, and its effect confirmed by wearer trials. The finish obtained has excellent durability, and its application to various Terylene and Terylene blend fabrics is described.