Non-intrusive methods for temperature measurements in liquid zones in microgravity environments

Material Science and Life Science experiments in microgravity both have urgent needs of evaluating the temperature distribution within and on the surface of liquid zones. Non intrusive methods are available which measure the IR radiations emitted by the surface. The thermograph systems have a number of advantages since they supply a thermal picture of the surface with sufficient time, space and temperature accuracy. A computerized system has been designed for data acquisition and elaboration and used for ground experiments; the system can also be used for space experiments with some modifications. Non intrusive measurements of bulk temperature in two dimensional liquid flow fields can be made by means of optical methods which detect variations of the index of refraction. A method is proposed which is able to take with the same optical apparatus shadowgraph. Schlieren and differential interferometers pictures. A computerized system is proposed for data acquisition and elaboration.     

The Voyager mission Photopolarimeter Experiment

The Voyager Photopolarimeter Experiment is designed to determine the physical properties of particulate matter in the atmospheres of Jupiter, Saturn, and the Rings of Saturn by measuring the intensity and linear polarization of scattered sunlight at eight wavelengths in the 2350–7500 Å region of the spectrum. The experiment will also provide information on the texture and probable composition of the surfaces of the satellites of Jupiter and Saturn and the properties of the sodium cloud around Io. During the planetary encounters a search for optical evidence of electrical discharges (lightning) and auroral activity will also be conducted.     

An Implementation of the Multidimensional Modified LMS Algorithm

An implementation of the multidimensional modified LMS algorithm is provided from its relationship to a recently developed class of lhyperstable adaptive filters.     

Environment and Radar Operation Simulator

The environment and radar operation simulator (EROS) is a hardware system whose function is to produce realistic synthetic radar backscatter, incorporating both target and clutter. The simulator is electrically connected to a subject radar and responds in real time to the radar's antenna scan angle by producing the correct composite video signal.     

The role of magnetic field shear in solar flares

We present observational results and their physical implications garnered from the deliberations of the FBS Magnetic Shear Study Group on magnetic field shear in relation to flares. The observed character of magnetic shear and its involvement in the buildup and release of flare energy are reviewed and illustrated with emphasis on recent results from the Marshall Space Flight Center vector magnetograph. It is pointed out that the magnetic field in active regions can become sheared by several processes, including shear flow in the photosphere, flux emergence, magnetic reconnection, and flux submergence. Modeling studies of the buildup of stored magnetic energy by shearing are reported which show ample energy storage for flares. Observational evidence is presented that flares are triggered when the field shear reaches a critical degree, in qualitative agreement with some theoretical analyses of sheared force-free fields. Finally, a scenario is outlined for the class of flares resulting from large-scale magnetic shear; the overall instability driving the energy release results from positive feedback between reconnection and eruption of the sheared field.     

Cell morphological, ontogenic, and genetic reactions to 0-g simulation and hyper-g

Organisms use gravity for spatial orientation, and differentiation into species during evolution follows geological processes which are caused by gravity. On the other hand, the task of most organismic functions which have or may have a relation to gravity is to compensate gravity. Furthermore, today it is very obvious that organisms do not disintegrate under the conditions of weightlessness, at least for the currently tested durations. These previous statements indicate a large field of still unknown regulation and adaptation mechanisms. Experiments to simulate weightlessness on the fast clinostat and with hyper-g show a highly developed ability of the genetic chain and of differentiating cells in being autonomous against mechanical stresses caused by outer accelerations. Nevertheless, different strong and slight changes of different tested end points were found. The question remains if the cells react actively or only passively.     

Small Aperture Angle Measurement for Active Echo Location Systems

The problem of bearing estimation for active systems is examined from the point of view of the generalized wideband ambiguity function (GAF). The maximum likelihood (ML) estimator is derived and its local and global properties are discussed. A structure is proposed which searches the three-dimensional ambiguity surface in two stages first, in range-Doppler, and then, in bearing with the goal of reducing search complexity when utilizing highly resolvent waveforms. Comparisons are made between the ML estimators and structures utilizing phase information which generate closed form estimators. The beneficial results of full bandwidth utilization are discussed in terms of both local and global properties of the GAF.     

Type Pi 1–2 magnetic field pulsations

The relationships of type Pi (broadband) pulsations to various other substorm-related phenomena are reviewed. Several of the more popular mechanisms for the origin of Pi activity are discussed in the light of the observations. There is only one mechanism in sight that tentatively accounts for observed characteristics of Pi 1–2 activity at auroral oval and polar cap latitudes and that is the three-dimensional current loop mechanism. If two or more mechanisms are involved in the generation of Pi noise, then it is possible that the garden-hose overstability and/or a drift Alfvén wave mechanism operating in the plasma sheet contribute to the observed pulsations.The common feature of all Pi 1–2 events is not the presence of temporal precipitation pulsations but the presence of an E-region, suggesting that enhanced conductivity and E-region currents are required. Pi activity appears to be closely related to unsteady convection in progress. Pi data promise to provide useful information on convection and field-aligned and ionospheric currents.