Tube System Transport Research Articles

Eruption constraints on tube‐fed planetary lava flows

We examine the role of pressure and gravity as driving forces in planetary lava tubes for Newtonian and power law rheologies. The tubes are assumed to have been filled with lava that was emplaced in constant diameter circular tubes in the laminar flow regime and had constant density, heat capacity, thermal conductivity, and viscosity. Our model provides relationships between tube dimensions, driving forces, and effusion rates and rheology parameters. In general, the pressure term in the driving force dominates for very small slopes, but the gravity term eclipses the pressure term as the slope increases. Applying the model to Alba Patera tube flows suggests effusion rates somewhere between 2 and 105 m3/s and viscosities between 102 and 106 Pa s, with tighter constraints (2 to 4 orders of magnitude) for specific tube sizes and travel times. These effusion rate results are lower and the viscosity ranges are higher than those found in previous studies. This allows eruptions that are closer in style to terrestrial basaltic eruptions, although the flows are still considerably larger in scale than the Hawaiian tube flows. We find that very low lava viscosities are not essential for Alba Patera lava tubes and that tube formation may be a better indicator of the steadiness of the eruption and the presence of low slopes than it is of low viscosities (e.g., 102 Pa s). In addition, this analysis suggests that the tube systems on the steep flanks of Olympus Mons are fundamentally different from those at Alba Patera. The Olympus Mons flows could not have roofed over, been continuously full, or maintained a continuous lava tube transport system in the assumed full, steady, and fully developed conditions.

Robotics-an efficient tool for laboratory automation

As part of a major upgrading of the Dyckerhoff AG, Amoneburg cement plant, Germany, a fully automated quality control and quality assurance system has been installed. The laboratory automation system is the robotics-based QCX/Robolab system. At the production laboratory, samples from nine automatic sampling points are brought by a pneumatic tube transport system to the industrial robot and distributed to sample preparation and analytical equipment. The robot-controlled analysis activity comprises X-ray fluorescence, X-ray diffraction, particle size distribution, and color measurement. The results are used for automatic process control applications. A number of manually operated analytical devices are connected to the system, allowing automatic analysis-data collection for activities like quality test of incoming and outgoing products, environmental protection, etc. Via a network, all analytical and associated production data from the production control system are automatically transferred to the central plant data management system.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The effect of bypass flows on heteroepitaxial growth of ZnS on GaP

A secondary gas flow, introduced between source and substrate, has been used in the growth of highly ordered ZnS layers on GaP substrates in a vapour phase open tube transport system. There is a critical ratio of total flow to carrier flow of about three, at which there is a sudden increase in growth rate. Flow visulisation experiments which elucidate this phenomena are described. It is shown that the effect is largely due to diffusion mechanisms, although turbulence in the region of the source material is involved to a lesser extent.

EFFECT OF PNEUMATIC TUBE TRANSPORT SYSTEM ON THE VALIDITY OF DETERMINATIONS IN BLOOD CHEMISTRY.

EFFECT OF PNEUMATIC TUBE TRANSPORT SYSTEM ON THE VALIDITY OF DETERMINATIONS IN BLOOD CHEMISTRY.