A stable and accurate control-volume technique based on integrated radial basis function networks for fluid-flow problems

Radial basis function networks (RBFNs) have been widely used in solving partial differential equations as they are able to provide fast convergence. Integrated RBFNs have the ability to avoid the problem of reduced convergence-rate caused by differentiation. This paper is concerned with the use of integrated RBFNs in the context of control-volume discretisations for the simulation of fluid-flow problems. Special attention is given to (i) the development of a stable high-order upwind scheme for the convection term and (ii) the development of a local high-order approximation scheme for the diffusion term. Benchmark problems including the lid-driven triangular-cavity flow are employed to validate the present technique. Accurate results at high values of the Reynolds number are obtained using relatively-coarse grids

Transformational Solar Array Option I Final Report

This report summarizes the work performed under NASA contract NNC16CA19C from May 2, 2017 through April 2, 2018. This work is directed toward meeting the goals of the associated NASA NRA and, of course, the requirements of the contract. In brief, the goals are: (1) Over 47% beginning of life cell efficiency at 5 AU and -125 C (2) Over 32% end of life efficiency at the blanket level at 50 W m-2, -125 C and 4E15 1 MeV e cm-2 (3) Over 8 W kg-1 at EOL for the entire array including structure, deployment, and pointing mechanisms using beginning of life performance. (4) A stowed packaging density of greater than 66 kW m-3 (5) An ability to survive launch and numerous deploy retract cycles without degradation (6) An output higher than 300 V (7) An ability to operate in a plasma generated by xenon thrusters, typically 1E8 cm-3 ions with an average energy of 2 eV (8) A design compatible with electrostatic and magnetic cleanliness (9) Record breaking inverted metamorphic (IMM) 6 junction solar cells (10) IMM solar cells that have no anomalous flat spot behavior at low irradiance and low temperature (11) A mock-up production line for the low-cost manufacture of spacecraft blanket arrays. The Option I phase of the project continued efforts, started in the base-phase, to eliminate or reduce to very low levels the flat spots that reduce power to an unacceptable value in a significant percentage of cells and to reduce outgassing contamination of the concentrators to acceptable levels. Option I adds tasks to increase the efficiency of IMM cells from those produced in the Base Phase, to eliminate delamination of the coatings that were present in previous versions of the concentrator mirrors, to evaluate pressure sensitive adhesive as a method of fixing solar cell assemblies to blankets, to design a magnetically clean brake for ROSA, to test the robustness of a sample blanket in deploy and retract, to test for the adequate performance of a blanket in vibration and thermal environments, and to define the capital equipment needed to optimize production of the Transformational Array. 5 Work for this Final Report showed that the greatest likely improvement in the solar cells would be by emphasizing the effort for the IMM4 solar cells and stopping work on other IMM cells. For this phase, the solar cell work was primarily on the IMM4 cells with little work on IMM5 and none on IMM6 cells

MEMS Gyroscopes for Consumers and Industrial Applications

none2mixedAntonello, Riccardo; Oboe, RobertoAntonello, Riccardo; Oboe, Robert

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 187

This supplement to Aerospace Medicine and Biology lists 247 reports, articles and other documents announced during November 1978 in Scientific and Technical Aerospace Reports (STAR) or in International Aerospace Abstracts (IAA). In its subject coverage, Aerospace Medicine and Biology concentrates on the biological, physiological, psychological, and environmental effects to which man is subjected during and following simulated or actual flight in the earth's atmosphere or in interplanetary space. References describing similar effects of biological organisms of lower order are also included. Emphasis is placed on applied research, but reference to fundamental studies and theoretical principles related to experimental development also qualify for inclusion. Each entry in the bibliography consists of a bibliographic citation accompanied in most cases by an abstract

Quantitative Endothelial Cell Monolayer Impedance Sensing and Analysis

The electrical analysis of the biological material has been in existence since the turn of last century. A novel application of this technology to cellular monolayers was implemented by Giaever and Keese 20 years ago with their Electrical Cell-Substrate Impedance Sensing (ECIS) system. The capabilities of a real-time system for endothelial impedance measurement are of immense importance. The endothelium is typically the body’s first contact with stimuli and its reaction to medical conditions of inflammation, disease, and body response are of great significance to understanding the physiology of numerous conditions ranging from heart, lung, and renal disease, to intestinal diseases. It is the purpose of this Master’s thesis to analyze and optimize the ECIS system for making quantitative measurements of endothelial monolayer impedance, and accurately applying the results to a thoroughly reviewed analysis package in order to produce accurate cellular resistance parameters. The optimization of data acquisition (DAQ) is accomplished by systematic noise recognition, examination, and minimization; a task that has previously been unexplored in any studies using the ECIS system. Harmonic, 60 Hz, and Gaussian noise sources were well documented in unfiltered data and successfully minimized in the DAQ. Analog to digital (A/D) noise was found to be the lower limit of reducible noise and was properly documented and considered in analysis. Contamination of the electrode arrays from manufacturing processes and proper electrical connection were also found to be of concern to the proper functioning of the system. Analysis of the optimized acquired data was performed in the LabVIEW programming environment, as it offered a more flexible software package than that provided by the current commercially available ECIS system. The optimized system was applied to a further look into hand arm-vibration syndrome (HAVS) and it was concluded that the acceleration exposure dose, incorrectly calculated from the international standards, did not elicit an acute endothelial inflammation response by our measurements. The cumulative result of this study is that the ECIS system has been optimized and various unresolved sources of error were corrected for a more accurate real-time measurement of the endothelial monolayer barrier function in response to stimuli

High-Throughput, Continuous Nanopatterning Technologies for Display and Energy Applications.

The motivation of this work is to enable continuous patterning of nanostructures on flexible substrates to push nanoscale lithography to an entirely new level with drastically increased throughput. The Roll-to-Roll Nanoimprint Lithography (R2RNIL) technology presented in this work retains the high-resolution feature capabilities of traditional NIL, but with an increase in throughput by at least one or two orders of magnitude. We demonstrated large-area (4” wide) continuous imprinting of nanogratings by using a newly developed apparatus capable of roll-to-roll imprinting on flexible substrates (R2RNIL) and roll-to-plate imprinting on rigid substrates (R2PNIL). In addition, analytical models were developed to predict the residual layer thickness in dynamic R2RNIL. As a potential application, high-performance metal wire-grid polarizers have also been fabricated utilizing R2RNIL. Another research focus involved Direct Metal Imprinting (DMI) to create discrete nano-scale metal gratings. DMI uses a polymer cushion layer between a thin metal layer and a hard substrate, which enables room-temperature nanoimprinting of the metal by overcoming troublesome hard-to-hard surface contact issues while preserving the Si mold. We also introduced a novel nanofabrication technique, Dynamic Nano-Inscribing (DNI) for creating truly continuous nanograting patterns by using the sharp edge of a tilted Si mold on a variety of metals or polymer materials, creating linewidths down to 50 nm at extremely high speeds (~100 mm/sec) under ambient conditions. Additionally, a new nanograting fabrication method, Localized Dynamic Wrinkling (LDW) has been developed. LDW enables the continuous formation of micro/nano-scale gratings by simply sliding a flat edge of a cleaved Si wafer over the metal film. LDW shares the same basic principle as the buckling (wrinkling) phenomenon but the moving edge of the tilted Si wafer exerts stress on a metal coated polymer and sequentially generates localized winkles in the metal film in a dynamic fashion. The period in LDW can be controlled by several processing parameters and shows good agreement with a theoretical model. Finally, we developed a Dynamic Nano-Cutting (DNC) process using high-frequency indentations on a moving substrate to sequentially create nanograting patterns. DNC provides perfectly straight lines with real-time period modulation, which is difficult to achieve by other nanomanufacturing techniques.Ph.D.Mechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/76015/1/happyash_1.pd

Research and Technology

Langley Research Center is engaged in the basic an applied research necessary for the advancement of aeronautics and space flight, generating advanced concepts for the accomplishment of related national goals, and provding research advice, technological support, and assistance to other NASA installations, other government agencies, and industry. Highlights of major accomplishments and applications are presented

High-power, ultralow-mass solar arrays: FY-77 solar arrays technology readiness assessment report, volume 2

Development efforts are reported in detail for: (1) a lightweight solar array system for solar electric propulsion; (2) a high efficiency thin silicon solar cell; (3) conceptual design of 200 W/kg solar arrays; (4) fluorocarbon encapsulation for silicon solar cell array; and (5) technology assessment of concentrator solar arrays

Aerial Vehicles

This book contains 35 chapters written by experts in developing techniques for making aerial vehicles more intelligent, more reliable, more flexible in use, and safer in operation.It will also serve as an inspiration for further improvement of the design and application of aeral vehicles. The advanced techniques and research described here may also be applicable to other high-tech areas such as robotics, avionics, vetronics, and space