Thematic mapper studies band correlation analysis

Spectral data representative of thematic mapper candidate bands 1 and 3 to 7 were obtained by selecting appropriate combinations of bands from the JSC 24 channel multispectral scanner. Of all the bands assigned, only candidate bands 4 (.74 mu to .80 mu) and 5 (.80 mu to .91 mu) showed consistently high intercorrelation from region to region and time to time. This extremely high correlation persisted when looking at the composite data set in a multitemporal, multilocation domain. The GISS investigations lend positive confirmation to the hypothesis, that TM bands 4 and 5 are redundant

Panel loss factors due to gas-pumping at structural joints

High frequency structural damping due to riveted joints associated with gas pumping between overlapping surface

Möbius gyrogroups: A Clifford algebra approach

AbstractUsing the Clifford algebra formalism we study the Möbius gyrogroup of the ball of radius t of the paravector space R⊕V, where V is a finite-dimensional real vector space. We characterize all the gyro-subgroups of the Möbius gyrogroup and we construct left and right factorizations with respect to an arbitrary gyro-subgroup for the paravector ball. The geometric and algebraic properties of the equivalence classes are investigated. We show that the equivalence classes locate in a k-dimensional sphere, where k is the dimension of the gyro-subgroup, and the resulting quotient spaces are again Möbius gyrogroups. With the algebraic structure of the factorizations we study the sections of Möbius fiber bundles inherited by the Möbius projectors

Hexagonal columnar phase in 1,4-trans-polybutadiene: morphology, chain extension, and isothermal phase reversal

Morphol., lamellar thickening, and the transition between the crystal and the hexagonal columnar phase were studied in 1,4-trans-polybutadiene (I) by optical and electron microscopy, time-resolved synchrotron x-ray diffraction, and DSC. I could form several-thousand-.ANG.-thick lamellas of the extended or nearly extended chain type. These could form either by direct growth from the melt or through annealing of thinner chain-folded lamellas, provided they were in the columnar phase. Lamellar thickness increased by several hundred .ANG. in soln.-crystd. mats immediately upon heating above the crystal-columnar transition, which contrasted with some previous reports on single crystals of I. The low-temp. crystal phase reappeared spontaneously on annealing above the temp. of the initial transition to the high-temp. columnar phase. [on SciFinder (R)

Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger

An active thermal control system architecture has been modified to include a regenerative heat exchanger (regenerator) inboard of the radiator. Rather than using a radiator bypass valve a regenerative heat exchanger is placed inboard of the radiators. A regenerator cold side bypass valve is used to set the return temperature. During operation, the regenerator bypass flow is varied, mixing cold radiator return fluid and warm regenerator outlet fluid to maintain the system setpoint. At the lowest heat load for stable operation, the bypass flow is closed off, sending all of the flow through the regenerator. This lowers the radiator inlet temperature well below the system set-point while maintaining full flow through the radiators. By using a regenerator bypass flow control to maintain system setpoint, the required minimum heat load to avoid radiator freezing can be reduced by more than half compared to a radiator bypass system

The role of transient hexagonal phase in crystallization of polymers

Crystn. studies of polyethylene (I) under hydrostatic pressure substantiate the findings by D. C. Bassett et al. that crystn. occurs initially in the hexagonal (h) phase, even within the thermodynamically stable orthorhombic (o) region. Present studies demonstrate that this is, in fact, a necessary condition for crystn., at least in the temp. and pressure range in question; in fact, once a crystal transforms from h to o phase, further growth of crystals stops. Morphol. features show that crystal growth includes both lateral and thickening growth; in the latter case the chains thicken continuously from folded to extended form and beyond. It is the thickness in a crystal which governs the phase inversion from h to o phase. Thickness dependence on phase inversion is explicitly shown in the trans-1,4-polybutadience, where the mobile h phase, similar to I, can exist, even at atm. pressure. [on SciFinder (R)

The role of transient hexagonal phase in crystallization of polymers

Crystn. studies of polyethylene (I) under hydrostatic pressure substantiate the findings by D. C. Bassett et al. that crystn. occurs initially in the hexagonal (h) phase, even within the thermodynamically stable orthorhombic (o) region. Present studies demonstrate that this is, in fact, a necessary condition for crystn., at least in the temp. and pressure range in question; in fact, once a crystal transforms from h to o phase, further growth of crystals stops. Morphol. features show that crystal growth includes both lateral and thickening growth; in the latter case the chains thicken continuously from folded to extended form and beyond. It is the thickness in a crystal which governs the phase inversion from h to o phase. Thickness dependence on phase inversion is explicitly shown in the trans-1,4-polybutadience, where the mobile h phase, similar to I, can exist, even at atm. pressure. [on SciFinder (R)

Molecular coding of information in the nervous system

Evidence has been accumulating in the last ten years to support the existence of a molecular code for the processing of information by the nervous system. The most direct evidence has been provided by the behavioral bioassay approach which has led to the isolation of training - induced and behavior-inducing peptides (mnemones). The most probable role of these peptides is to establish and consolidate the connection sof the neural circuits in which information is stored. Although this coding process is based on the genetically controlled labeling system by which neurons are organized into specific pathways, it must involve a step of non-genetic peptide synthesis.G. UNGAR, Baylor College of Medicine, Houston, Texas

Formation of a Double Diamond Cubic Phase by Thermotropic Liquid Crystalline Self-Assembly of Bundled Bolaamphiphiles

A quaternary amphiphile with swallow-tail side groups displays a new bicontinuous thermotropic cubic phase with symmetry Pn3‾ m and formed by two interpenetrating networks where cylindrical segments are linked by H bonds at tetrahedral junctions. Each network segment contains two bundles, each containing 12 rod-like mesogens, lying along the segment axis. This assembly leads to the first thermotropic structure of the "double diamond" type. A quantitative geometric model is proposed to explain the occurrence of this rare phase