Measuring Complexity in an Aquatic Ecosystem

We apply formal measures of emergence, self-organization, homeostasis, autopoiesis and complexity to an aquatic ecosystem; in particular to the physiochemical component of an Arctic lake. These measures are based on information theory. Variables with an homogeneous distribution have higher values of emergence, while variables with a more heterogeneous distribution have a higher self-organization. Variables with a high complexity reflect a balance between change (emergence) and regularity/order (self-organization). In addition, homeostasis values coincide with the variation of the winter and summer seasons. Autopoiesis values show a higher degree of independence of biological components over their environment. Our approach shows how the ecological dynamics can be described in terms of information.Comment: 6 pages, to be published in Proceedings of the CCBCOL 2013, 2nd Colombian Computational Biology Congress, Springe

Status and Evaluation of Microwave Furnace Capabilities at NASA Glenn Research Center

The microwave (MW) furnace is a HY-Tech Microwave Systems, 2 kW 2.45 GHz Single Mode Microwave Applicator operating in continuous wave (CW) with variable power. It is located in Cleveland, Ohio at NASA Glenn Research Center. Until recently, the furnace capabilities had not been fully realized due to unknown failure that subsequently damaged critical furnace components. Although the causes of the problems were unknown, an assessment of the furnace itself indicated operational failure may have been partially caused by power quality. This report summarizes the status of the MW furnace and evaluates its capabilities in materials processing

Modelling diffuse instabilities in sands under drained conditions

This paper presents a criterion for detecting diffuse (homogeneous) instabilities in granular soils sheared under fully drained conditions. The criterion is based on bifurcation theory and applied to elasto-plasticity by allowing multiple incremental solutions in elasto-plastic soils, physically losing controllability of stress boundary conditions. Drained diffuse instabilities are poorly understood, and are induced by kinematic modes different from those observed in shear bands and liquefaction instabilities. Unlike shear bands, diffuse instabilities occur under fairly homogenous deformation modes and, unlike liquefaction, drained instabilities are not generated by the excess pore pressures. Recent experiments under drained constant shear report sudden homogeneous instabilities in samples of relatively dense and loose sands. The criterion presented in this paper is used in conjunction with an elasto-plasticity model for sands to predict and explain these reported drained instabilities. From a practical standpoint, these developments serve to expand the repertoire of potential instabilities that occur well before failure, and which have been reported in case studies of puzzling slope instability failures under fully drained conditions

Effect of frictional heat dissipation on the loss of soil strength

In the present paper through a shear test on a fully saturated granular medium, simulated by the discrete element method, the effect of the heat produced by friction on the internal pore water pressure is explored. It is found that the dissipated energy is enough to increase the pore pressure and reduce the soil strength. In adiabatic and impermeable conditions the heat builds up quickly inside the shear band, and the softening is more pronounced. It is found as well that for real geological materials, heat conduction is not enough to reduce the pore pressure, and the softening prevails. Nevertheless, it is observed that the hydraulic conduction may mitigate or completely eliminate the temperature growth inside the shear band. This result provides new understanding on the thermodynamic factors involved in the onset of catastrophic landslides

Fabrication of Boron Nitride Fibers by Force Spinning Method

The unique multifunctional properties of boron nitride (BN) nanomaterials are identified as a parameter that would revolutionize electric propulsion in Aeronautics due to the lightweight ceramic with chemical inertness, high strength, high electrical resistivity and high thermal conductivity. Hexagonal BN (h-BN) nanofibers will enable new high-performance fibers that can be used in ceramic or polymer matrix composites, or thin films to provide revolutionary multifunctional ceramics for extreme environments and structures. Polymer derived h-BN materials have been previously demonstrated, providing an avenue to tailor properties of the ceramic end product. This effort also uses forcespinning (FS) technology that produces continuous non-woven nanofibers in a range of diameters depending on the processing parameters with a large production rate of 1 g/min allowing for manufacturing scale production. FTIR, SEM, TGA and XRD were used to characterize the materials in each processing steps

Lightweight, Durable, and Multifunctional Electrical Insulation Material Systems for High Voltage Applications

Newly developed multilayer structures of well-known polymer insulation materials significantly improved dielectric breakdown voltage, VB, or dielectric strength, K, if well-bonded, when compared to those of single material insulations or the commercial SOA systems, such as Teflon-Kapton-Teflon (TKT), at the same overall thickness. To date, the greatest improvement of the new structures from a few candidate materials, including various types of Kapton PIs and PFA or PET as bond layer (BL), was about 61% higher than that of the Kapton PI alone films, 40.1 vs. 24.9 kV, which was translated to 86.3% decrease in insulation thickness, thus significant volume and weight reduction of the final system. However, it was of interest to note that most improvements of the multilayer structures occurred at thicker overall thicknesses, above ~ 0.15 mm. Extensive analyses also showed that K of the multilayer structures increased with (i) decreasing individual layer thickness regardless of material type, (ii) increasing total accumulated thickness of PI or overall PI/BL ratio, and (iii) increasing number of interface or total number of layers, but only above the aforementioned overall thickness limit. Increases in VB of the multilayer structures were directly correlated with damage evolution and failure mode. With further material-design-process optimizations of the multilayer structures, it was expected to achieve other multifunctionalities, such as high partial discharge (PD) resistance, improved durability, EMI shielding, and high thermal dissipation in addition to high dielectric strength. These new structures can be used in various high voltage and high temperature applications, such as future hybrid or all electric aircraft wiring and power transmission as well as many other non-aerospace high power cables, electronic parts and components, printed circuit board, and so forth. The multilayer insulation system can be easily processed and manufactured with various conductor types via calendaring, compression-molding, stamping, laminating, vacuum-bagging and autoclaving, or 3D printing, even for complex 3-D components. Based on their unique structural configurations and potential capabilities, the new insulation system was identified as micro-multilayer multifunctional electrical insulation (MMEI). Patent application of the MMEI concept and current design configurations was filed for a 1-year provisional application (OAI-58834, Serial No.: 62/659,234), pending conversion to a U.S. utility application. This paper presents details of the MMEI structures, their dielectric performance analyses, potential mechanisms, and commercial scaleup feasibility assessment