Issue Date
1995-11Keywords
ModularityParallel Processing
Distributed Processing
Symmetrical Processing
Multi-mission Concept
Total Mission Concept
Ground System Process Control
Metadata
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Copyright © International Foundation for TelemeteringCollection Information
Proceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection.Abstract
Embedded parallel processing provides unique advantages over sequential and symmetrical processing architectures. During the past decade, the architecture of ground control systems has evolved from utilizing sequential embedded processors to modular parallel, distributed, and/or symmetrical processing. The concept of utilizing embedded parallel processing exhibits key features such as modularity, flexibility, scalability, host independence, non-contention of host resources, and no requirement for an operating system. These key features provide the performance, reliability and efficiency while at the same time lowering costs. Proper utilization of embedded parallel processing on a host computer can provide fault tolerance and can greatly reduce the costs and the requirement of utilizing high-end workstations to perform the same level of real-time processing and computationally intensive tasks.Sponsors
International Foundation for TelemeteringISSN
0884-51230074-9079
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Showing items related by title, author, creator and subject.
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Simulation of pecan processing for evaluation of process alternativesShoup, W. David; Lakhani, Muhammad Bashir, 1960- (The University of Arizona., 1997)A number of alternatives were considered to keep pecan processing economically competitive and sustainable. The industry needed a low risk evaluation technique for testing new high capital plant configurations. A simulation model was developed using the AweSimTM simulation system to form the model structure and framework. The Visual SLAMTM and Visual BASIC programming languages were used to build a network model that provided a mathematical-logical representation of the system. The model mathematically expresses all sub-processes including moisture conditioning, pasteurizing, cracking, shelling, sizing, manual and electronic sorting, resizing, resorting, and packaging. The pecan process simulation model consists of 24 RESOURCES, 353 ACTIVITIES, 48 AWAIT/QUEUE and FREE nodes, 83 BATCH and UNBATCH nodes, 79 ASSIGN nodes, 20 COLCT nodes, 39 GOON nodes, 10 other miscellaneous nodes and a graphic user interface (GUI). The model provides information on equipment utilization, delays, queues and bottlenecks for each process in the system. It also predicts total pecan cracked and total pecan packed, including details of production for each size class i.e. halves; large; medium; small; midget; fine; granule; and oil stock. The model was validated quantitatively by comparing output with actual production figures and qualitatively by plant management. Five options of process alternatives were simulated using the pecan simulation model. The first alternative (including 3 options) was a management proposed configuration for dual electronic sorting of pecan halves to reduce the shell pieces and ensure a lighter color product. Two options were found not viable as they required major capital investments and plant reconfiguration. The third option for dual sorting was found to be a viable process alternative with minor labor additions.
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Processing High Purity Zirconium Diboride Ultra-High Temperature Ceramics: Small-to-Large Scale ProcessingCorral, Erica L.; Pham, David; Corral, Erica L.; Muralidharan, Krishna; Loy, Doug; Manga, Venkateswara R. (The University of Arizona., 2016)Next generation aerospace vehicles require thermal protection system (TPS) materials that are capable of withstanding the extreme aerothermal environment during hypersonic flight (>Mach 5 [>1700 m/s]). Ultra-high temperature ceramics (UHTC) such as zirconium diboride (ZrB₂) are candidate TPS materials due to their high-temperature thermal and mechanical properties and are often the basis for advanced composites for enhanced oxidation resistance. However, ZrB₂ matrix impurities in the form of boron trioxide (B₂O₃) and zirconium dioxide (ZrO₂) limit the high-temperature capabilities. Electric based sintering techniques, such as spark plasma sintering (SPS), that use joule heating have become the preferred densification method to process advanced ceramics due to its ability to produce high density parts with reduced densification times and limit grain growth. This study focuses on a combined experimental and thermodynamic assisted processing approach to enhance powder purity through a carbo- and borocarbo-thermal reduction of oxides using carbon (C) and boron carbide (B₄C). The amount of oxides on the powder surface are measured, the amount of additive required to remove oxides is calculated, and processing conditions (temperature, pressure, environment) are controlled to promote favorable thermodynamic reactions both during thermal processing in a tube furnace and SPS. Untreated ZrB₂ contains 0.18 wt%O after SPS. Additions of 0.75 wt%C is found to reduce powder surface oxides to 0.12 wt%O. A preliminary Zr-C-O computational thermodynamic model shows limited efficiency of carbon additions to completely remove oxygen due to the solubility of oxygen in zirconium carbide (ZrC) forming a zirconium oxycarbide (ZrCₓOᵧ). Scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM) with atomic scale elemental spectroscopy shows reduced oxygen content with amorphous Zr-B oxides and discreet ZrO₂ particle impurities in the microstructure. Processing ZrB₂ with minimal additions of B₄C (0.25 wt%) produces high purity parts after SPS with only 0.06 wt%O. STEM identifies unique “trash collector” oxides composed of manufacturer powder impurities of calcium, silver, and yttrium. A preliminary Zr-B-C-O thermodynamic model is used to show the potential reaction paths using B₄C that promotes oxide removal to produce high-purity ZrB₂ with fine grains (3.3 𝜇m) and superior mechanical properties (flexural strength of 660MPa) than the current state-of-the-art ZrB₂ ceramics. Due to the desirable properties produced using SPS, there is growing interest to advance processing techniques from lab-scale (20 mm discs) to large-scale (>100 mm). The advancement of SPS technologies has been stunted due to the limited power and load delivery of lab-scale furnaces. We use a large scale direct current sintering furnace (DCS) to address the challenges of producing industrially relevant sized parts. However, current-assisted sintering techniques, like SPS and DCS, are highly dependent on tooling resistances and the electrical conductivity of the sample, which influences the part uniformity through localized heating spots that are strongly dependent on the current flow path. We develop a coupled thermal-electrical finite element analysis model to investigate the development and effects of tooling and current density manipulation on an electrical conductor (ZrB₂) and an electrical insulator, silicon nitride (Si₃N₄), at the steady-state where material properties, temperature gradients and current/voltage input are constant. The model is built based on experimentally measured temperature gradients in the tooling for 20 mm discs and validated by producing 30 mm discs with similar temperature gradients and grain size uniformity across the part. The model aids in developing tooling to manipulate localize current density in specific regions to produce uniform 100 mm discs of ZrB₂ and Si₃N₄.
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A process design study for a raw sugar crystallization processRuiz Gecosala, Rinly (The University of Arizona., 1979)