Panel acoustic contribution analysis.

PubMed

Wu, Sean F; Natarajan, Logesh Kumar

2013-02-01

Formulations are derived to analyze the relative panel acoustic contributions of a vibrating structure. The essence of this analysis is to correlate the acoustic power flow from each panel to the radiated acoustic pressure at any field point. The acoustic power is obtained by integrating the normal component of the surface acoustic intensity, which is the product of the surface acoustic pressure and normal surface velocity reconstructed by using the Helmholtz equation least squares based nearfield acoustical holography, over each panel. The significance of this methodology is that it enables one to analyze and rank relative acoustic contributions of individual panels of a complex vibrating structure to acoustic radiation anywhere in the field based on a single set of the acoustic pressures measured in the near field. Moreover, this approach is valid for both interior and exterior regions. Examples of using this method to analyze and rank the relative acoustic contributions of a scaled vehicle cabin are demonstrated.

Mechanical and thermal buckling analysis of rectangular sandwich panels under different edge conditions

NASA Technical Reports Server (NTRS)

Ko, William L.

1994-01-01

The combined load (mechanical or thermal load) buckling equations were established for orthotropic rectangular sandwich panels under four different edge conditions by using the Rayleigh-Ritz method of minimizing the total potential energy of a structural system. Two-dimensional buckling interaction curves and three-dimensional buckling interaction surfaces were constructed for high-temperature honeycomb-core sandwich panels supported under four different edge conditions. The interaction surfaces provide overall comparison of the panel buckling strengths and the domains of symmetrical and antisymmetrical buckling associated with the different edge conditions. In addition, thermal buckling curves of these sandwich panels are presented. The thermal buckling conditions for the cases with and without thermal moments were found to be identical for the small deformation theory.

Laser Ablation Cleaning of Self-Reacting Friction Stir Weld Seam Surfaces: A Preliminary Evaluation

NASA Technical Reports Server (NTRS)

Nunes, A. C., Jr.; Russell, C. K.; Brooke, S. A.; Parry, Q.; Lowrey, N. M.

2014-01-01

Anodized aluminum panels were cleaned by three lasers at three separate sites with a view to determining whether more economical laser cleaning might supplant current manual cleaning methods for preparation of surfaces to be welded by the self-reacting friction stir process. Uncleaned panels yielded welds exhibiting residual oxide defect (ROD) and failing at very low stresses along the trace of the weld seam. Manually cleaned panels yielded welds without ROD; these welds failed at nominal stress levels along an angled fracture surface not following the weld seam trace. Laser cleaned panels yielded welds failing at intermediate stress levels. The inadequacy of the laser cleaning processes leaves questions: Was the anodized aluminum test too stringent to represent actual cleaning requirements? Were the wrong laser cleaning techniques/parameters used for the study? Is the laser cleaning mechanism inadequate for effective preweld surface cleaning?

Linear Strength Vortex Panel Method for NACA 4412 Airfoil

NASA Astrophysics Data System (ADS)

Liu, Han

2018-03-01

The objective of this article is to formulate numerical models for two-dimensional potential flow over the NACA 4412 Airfoil using linear vortex panel methods. By satisfying the no penetration boundary condition and Kutta condition, the circulation density on each boundary points (end point of every panel) are obtained and according to which, surface pressure distribution and lift coefficients of the airfoil are predicted and validated by Xfoil, an interactive program for the design and analysis of airfoil. The sensitivity of results to the number of panels is also investigated in the end, which shows that the results are sensitive to the number of panels when panel number ranges from 10 to 160. With the increasing panel number (N>160), the results become relatively insensitive to it.

Dynamic Data Driven Methods for Self-aware Aerospace Vehicles

DTIC Science & Technology

2015-04-08

structural response model that incorporates multiple degradation or failure modes including damaged panel strength (BVID, thru- hole ), damaged panel...stiffness (BVID, thru- hole ), loose fastener, fretted fastener hole , and disbonded surface. • A new data-driven approach for the online updating of the flight...between the first and second plies. The panels were reinforced around the boarders of the panel with through holes to simulate mounting the wing skins to

Method for high-accuracy reflectance measurements in the 2.5-microm region.

PubMed

Richter, Rudolf; Müller, Andreas

2003-02-20

Reflectance measurement with spectroradiometers in the solar wavelength region (0.4-2.5 microm) are frequently conducted in the laboratory or in the field to characterize surface materials of artificial and natural targets. The spectral surface reflectance is calculated as the ratio of the signals obtained over the target surface and a reference panel, yielding a relative reflectance value. If the reflectance of the reference panel is known, the absolute target reflectance can be computed. This standard measurement technique assumes that the signal at the radiometer is due completely to reflected target and reference radiation. However, for field measurements in the 2.4-2.5-microm region with the Sun as the illumination source, the emitted thermal radiation is not a negligible part of the signal even at ambient temperatures, because the atmospheric transmittance, and thus the solar illumination level, is small in the atmospheric absorption regions. A new method is proposed that calculates reflectance values in the 2.4-2.5-microm region while it accounts for the reference panel reflectance and the emitted radiation. This technique needs instruments with noise-equivalent radiances of 2 orders of magnitude below currently commercially available instruments and requires measurement of the surface temperatures of target and reference. If the reference panel reflectance and temperature effects are neglected, the standard method yields reflectance errors up to 0.08 and 0.15 units for 7- and 2-nm bandwidth instruments, respectively. For the new method the corresponding errors can be reduced to approximately 0.01 units for the surface temperature range of 20-35 degrees C.

An advanced panel method for analysis of arbitrary configurations in unsteady subsonic flow

NASA Technical Reports Server (NTRS)

Dusto, A. R.; Epton, M. A.

1980-01-01

An advanced method is presented for solving the linear integral equations for subsonic unsteady flow in three dimensions. The method is applicable to flows about arbitrary, nonplanar boundary surfaces undergoing small amplitude harmonic oscillations about their steady mean locations. The problem is formulated with a wake model wherein unsteady vorticity can be convected by the steady mean component of flow. The geometric location of the unsteady source and doublet distributions can be located on the actual surfaces of thick bodies in their steady mean locations. The method is an outgrowth of a recently developed steady flow panel method and employs the linear source and quadratic doublet splines of that method.

Connecting node and method for constructing a connecting node

NASA Technical Reports Server (NTRS)

Johnson, Christopher J. (Inventor); Raboin, Jasen L. (Inventor); Spexarth, Gary R. (Inventor)

2011-01-01

A connecting node comprises a polyhedral structure comprising a plurality of panels joined together at its side edges to form a spherical approximation, wherein at least one of the plurality of panels comprises a faceted surface being constructed with a passage for integrating with one of a plurality of elements comprising a docking port, a hatch, and a window that is attached to the connecting node. A method for manufacturing a connecting node comprises the steps of providing a plurality of panels, connecting the plurality of panels to form a spherical approximation, wherein each edge of each panel of the plurality is joined to another edge of another panel, and constructing at least one of the plurality of panels to include a passage for integrating at least one of a plurality of elements that may be attached to the connecting node.

Development of Guidelines for In-Situ Repair of SLS-Class Composite Flight Hardware

NASA Technical Reports Server (NTRS)

Weber, Thomas P., Jr.; Cox, Sarah B.

2018-01-01

The purpose of composite repair development at KSC (John F. Kennedy Space Center) is to provide support to the CTE (Composite Technology for Exploration) project. This is a multi-space center effort with the goal of developing bonded joint technology for SLS (Space Launch System) -scale composite hardware. At KSC, effective and efficient repair processes need to be developed to allow for any potential damage to composite components during transport or launch preparation. The focus of the composite repair development internship during the spring of 2018 was on the documentation of repair processes and requirements for process controls based on techniques developed through hands-on work with composite test panels. Three composite test panels were fabricated for the purpose of repair and surface preparation testing. The first panel included a bonded doubler and was fabricated to be damaged and repaired. The second and third panels were both fabricated to be cut into lap-shear samples to test the strength of bond of different surface preparation techniques. Additionally, jointed composite test panels were impacted at MSFC (Marshall Space Flight Center) and analyzed for damage patterns. The observations after the impact tests guided the repair procedure at KSC to focus on three repair methods. With a finalized repair plan in place, future work will include the strength testing of different surface preparation techniques, demonstration of repair methods, and repair of jointed composite test panels being impacted at MSFC.

Mechanical and thermal buckling analysis of sandwich panels under different edge conditions

NASA Technical Reports Server (NTRS)

Ko, William L.

1993-01-01

By using the Rayleigh-Ritz method of minimizing the total potential energy of a structural system, combined load (mechanical or thermal load) buckling equations are established for orthotropic rectangular sandwich panels supported under four different edge conditions. Two-dimensional buckling interaction curves and three dimensional buckling interaction surfaces are constructed for high-temperature honeycomb-core sandwich panels supported under four different edge conditions. The interaction surfaces provide easy comparison of the panel buckling strengths and the domains of symmetrical and antisymmetrical buckling associated with the different edge conditions. Thermal buckling curves of the sandwich panels also are presented. The thermal buckling conditions for the cases with and without thermal moments were found to be identical for the small deformation theory. In sandwich panels, the effect of transverse shear is quite large, and by neglecting the transverse shear effect, the buckling loads could be overpredicted considerably. Clamping of the edges could greatly increase buckling strength more in compression than in shear.

Aerodynamic influence coefficient method using singularity splines

NASA Technical Reports Server (NTRS)

Mercer, J. E.; Weber, J. A.; Lesferd, E. P.

1974-01-01

A numerical lifting surface formulation, including computed results for planar wing cases is presented. This formulation, referred to as the vortex spline scheme, combines the adaptability to complex shapes offered by paneling schemes with the smoothness and accuracy of loading function methods. The formulation employes a continuous distribution of singularity strength over a set of panels on a paneled wing. The basic distributions are independent, and each satisfied all the continuity conditions required of the final solution. These distributions are overlapped both spanwise and chordwise. Boundary conditions are satisfied in a least square error sense over the surface using a finite summing technique to approximate the integral. The current formulation uses the elementary horseshoe vortex as the basic singularity and is therefore restricted to linearized potential flow. As part of the study, a non planar development was considered, but the numerical evaluation of the lifting surface concept was restricted to planar configurations. Also, a second order sideslip analysis based on an asymptotic expansion was investigated using the singularity spline formulation.

Probabilistic Thermal Analysis During Mars Reconnaissance Orbiter Aerobraking

NASA Technical Reports Server (NTRS)

Dec, John A.

2007-01-01

A method for performing a probabilistic thermal analysis during aerobraking has been developed. The analysis is performed on the Mars Reconnaissance Orbiter solar array during aerobraking. The methodology makes use of a response surface model derived from a more complex finite element thermal model of the solar array. The response surface is a quadratic equation which calculates the peak temperature for a given orbit drag pass at a specific location on the solar panel. Five different response surface equations are used, one of which predicts the overall maximum solar panel temperature, and the remaining four predict the temperatures of the solar panel thermal sensors. The variables used to define the response surface can be characterized as either environmental, material property, or modeling variables. Response surface variables are statistically varied in a Monte Carlo simulation. The Monte Carlo simulation produces mean temperatures and 3 sigma bounds as well as the probability of exceeding the designated flight allowable temperature for a given orbit. Response surface temperature predictions are compared with the Mars Reconnaissance Orbiter flight temperature data.

A vectorization of the Hess McDonnell Douglas potential flow program NUED for the STAR-100 computer

NASA Technical Reports Server (NTRS)

Boney, L. R.; Smith, R. E., Jr.

1979-01-01

The computer program NUED for analyzing potential flow about arbitrary three dimensional lifting bodies using the panel method was modified to use vector operations and run on the STAR-100 computer. A high speed of computation and ability to approximate the body surface with a large number of panels are characteristics of NUEDV. The new program shows that vector operations can be readily implemented in programs of this type to increase the computational speed on the STAR-100 computer. The virtual memory architecture of the STAR-100 facilitates the use of large numbers of panels to approximate the body surface.

Aerodynamic influence coefficient method using singularity splines.

NASA Technical Reports Server (NTRS)

Mercer, J. E.; Weber, J. A.; Lesferd, E. P.

1973-01-01

A new numerical formulation with computed results, is presented. This formulation combines the adaptability to complex shapes offered by paneling schemes with the smoothness and accuracy of the loading function methods. The formulation employs a continuous distribution of singularity strength over a set of panels on a paneled wing. The basic distributions are independent, and each satisfies all of the continuity conditions required of the final solution. These distributions are overlapped both spanwise and chordwise (termed 'spline'). Boundary conditions are satisfied in a least square error sense over the surface using a finite summing technique to approximate the integral.

Energy transmission through a double-wall curved stiffened panel using Green's theorem

NASA Astrophysics Data System (ADS)

Ghosh, Subha; Bhattacharya, Partha

2015-04-01

It is a common practice in aerospace and automobile industries to use double wall panels as fuselage skins or in window panels to improve acoustic insulation. However, the scientific community is yet to develop a reliable prediction method for a suitable vibro-acoustic model for sound transmission through a curved double-wall panel. In this quest, the present work tries to delve into the modeling of energy transmission through a double-wall curved panel. Subsequently the radiation of sound power into the free field from the curved panel in the low to mid frequency range is also studied. In the developed model to simulate a stiffened aircraft fuselage configuration, the outer wall is provided with longitudinal stiffeners. A modal expansion theory based on Green's theorem is implemented to model the energy transmission through an acoustically coupled double-wall curved panel. An elemental radiator approach is implemented to calculate the radiated energy from the curved surface in to the free field. The developed model is first validated with various numerical models available. It has been observed in the present study that the radius of curvature of the surface has a prominent effect on the behavior of radiated sound power into the free field. Effect of the thickness of the air gap between the two curved surfaces on the sound power radiation has also been noted.

A general panel method for the analysis and design of arbitrary configurations in incompressible flows. [boundary value problem

NASA Technical Reports Server (NTRS)

Johnson, F. T.

1980-01-01

A method for solving the linear integral equations of incompressible potential flow in three dimensions is presented. Both analysis (Neumann) and design (Dirichlet) boundary conditions are treated in a unified approach to the general flow problem. The method is an influence coefficient scheme which employs source and doublet panels as boundary surfaces. Curved panels possessing singularity strengths, which vary as polynomials are used, and all influence coefficients are derived in closed form. These and other features combine to produce an efficient scheme which is not only versatile but eminently suited to the practical realities of a user-oriented environment. A wide variety of numerical results demonstrating the method is presented.

Improvements to the missile aerodynamic prediction code DEMON3

NASA Technical Reports Server (NTRS)

Dillenius, Marnix F. E.; Johnson, David L.; Lesieutre, Daniel J.

1992-01-01

The computer program DEMON3 was developed for the aerodynamic analysis of nonconventional supersonic configurations comprising a body with noncircular cross section and up to two wing or fin sections. Within a wing or fin section, the lifting surfaces may be cruciform, triform, planar, or low profile layouts; the planforms of the lifting surfaces allow for breaks in sweep. The body and fin sections are modeled by triplet and constant u-velocity panels, respectively, accounting for mutual body-fin interference. Fin thickness effects are included for the use of supersonic planar source panels. One of the unique features of DEMON3 is the modeling of high angle of attack vortical effects associated with the lifting surfaces and the body. In addition, shock expansion and Newtonian pressure calculation methods can be optionally engaged. These two dimensional nonlinear methods are augmented by aerodynamic interference determined from the linear panel methods. Depending on the geometric details of the body, the DEMON3 program can be used to analyze nonconventional configurations at angles of attack up to 25 degrees for Mach numbers from 1.1 to 6. Calculative results and comparisons with experimental data demonstrate the capabilities of DEMON3. Limitations and deficiencies are listed.

Thermal stability tests of CFRP sandwich panels for far infrared astronomy

NASA Technical Reports Server (NTRS)

Hoffmann, W. F.; Helwig, G.; Scheulen, D.

1986-01-01

An account is given of fabrication methods and low temperature figure tests for CFRP sandwich panels, in order to ascertain their applicability to ultralightweight 3-m aperture primary mirrors for balloon-borne sub-mm and far-IF telescopes that must maintain a 1-2 micron rms surface figure accuracy at -40 to -50 C. Optical figure measurements on the first two of a series of four 0.5-m test panels, replicated to a spherical surface, show a radius-of-curvature change and astigmatism down to -60 C; this approximately follows the composite's theoretical predictions and implies that material and process control is excellent, so that the large scale changes observed can be compensated for.

Validation of Methods to Predict Vibration of a Panel in the Near Field of a Hot Supersonic Rocket Plume

NASA Technical Reports Server (NTRS)

Bremner, P. G.; Blelloch, P. A.; Hutchings, A.; Shah, P.; Streett, C. L.; Larsen, C. E.

2011-01-01

This paper describes the measurement and analysis of surface fluctuating pressure level (FPL) data and vibration data from a plume impingement aero-acoustic and vibration (PIAAV) test to validate NASA s physics-based modeling methods for prediction of panel vibration in the near field of a hot supersonic rocket plume. For this test - reported more fully in a companion paper by Osterholt & Knox at 26th Aerospace Testing Seminar, 2011 - the flexible panel was located 2.4 nozzle diameters from the plume centerline and 4.3 nozzle diameters downstream from the nozzle exit. The FPL loading is analyzed in terms of its auto spectrum, its cross spectrum, its spatial correlation parameters and its statistical properties. The panel vibration data is used to estimate the in-situ damping under plume FPL loading conditions and to validate both finite element analysis (FEA) and statistical energy analysis (SEA) methods for prediction of panel response. An assessment is also made of the effects of non-linearity in the panel elasticity.

Solution of plane cascade flow using improved surface singularity methods. [application of panel method to internal aerodynamics

NASA Technical Reports Server (NTRS)

Mcfarland, E. R.

1981-01-01

A solution method was developed for calculating compressible inviscid flow through a linear cascade of arbitrary blade shapes. The method uses advanced surface singularity formulations which were adapted from those in current external flow analyses. The resulting solution technique provides a fast flexible calculation for flows through turbomachinery blade rows. The solution method and some examples of the method's capabilities are presented.

Imaging and Information Processing of Pitting-Corroded Aluminum Alloy Panels with Surface Metrology Methods

DTIC Science & Technology

2014-12-23

positioned outside the sealed chamber by passing extension cables through the bulkhead in the chamber. Temperature and relative humidity were acquired at...inside the chamber was varied in temperature and humidity to promote corrosion. Panels 1-3 were removed 133, 209 and 286 hours from the experiment...indicated that, the nucleated pits, as those general non- visible ones in Panel 1, usually took regular morphological forms, such as hemi-spherical, near

A method for the reduction of aerodynamic drag of road vehicles

NASA Technical Reports Server (NTRS)

Pamadi, Bandu N.; Taylor, Larry W.; Leary, Terrance O.

1990-01-01

A method is proposed for the reduction of the aerodynamic drag of bluff bodies, particularly for application to road transport vehicles. This technique consists of installation of panels on the forward surface of the vehicle facing the airstream. With the help of road tests, it was demonstrated that the attachment of proposed panels can reduce aerodynamic drag of road vehicles and result in significant fuel cost savings and conservation of energy resources.

An improved panel method for the solution of three-dimensional leading-edge vortex flows. Volume 1: Theory document

NASA Technical Reports Server (NTRS)

Johnson, F. T.; Lu, P.; Tinoco, E. N.

1980-01-01

An improved panel method for the solution of three dimensional flow and wing and wing-body combinations with leading edge vortex separation is presented. The method employs a three dimensional inviscid flow model in which the configuration, the rolled-up vortex sheets, and the wake are represented by quadratic doublet distributions. The strength of the singularity distribution as well as shape and position of the vortex spirals are computed in an iterative fashion starting with an assumed initial sheet geometry. The method calculates forces and moments as well as detail surface pressure distributions. Improvements include the implementation of improved panel numerics for the purpose of elimination the highly nonlinear effects of ring vortices around double panel edges, and the development of a least squares procedure for damping vortex sheet geometry update instabilities. A complete description of the method is included. A variety of cases generated by the computer program implementing the method are presented which verify the mathematical assumptions of the method and which compare computed results with experimental data to verify the underlying physical assumptions made by the method.

Active control of sound radiation from a vibrating rectangular panel by sound sources and vibration inputs - An experimental comparison

NASA Technical Reports Server (NTRS)

Fuller, C. R.; Hansen, C. H.; Snyder, S. D.

1991-01-01

Active control of sound radiation from a rectangular panel by two different methods has been experimentally studied and compared. In the first method a single control force applied directly to the structure is used with a single error microphone located in the radiated acoustic field. Global attenuation of radiated sound was observed to occur by two main mechanisms. For 'on-resonance' excitation, the control force had the effect of increasing the total panel input impedance presented to the nosie source, thus reducing all radiated sound. For 'off-resonance' excitation, the control force tends not significantly to modify the panel total response amplitude but rather to restructure the relative phases of the modes leading to a more complex vibration pattern and a decrease in radiation efficiency. For acoustic control, the second method, the number of acoustic sources required for global reduction was seen to increase with panel modal order. The mechanism in this case was that the acoustic sources tended to create an inverse pressure distribution at the panel surface and thus 'unload' the panel by reducing the panel radiation impedance. In general, control by structural inputs appears more effective than control by acoustic sources for structurally radiated noise.

Computer prediction of large reflector antenna radiation properties

NASA Technical Reports Server (NTRS)

Botula, A.

1980-01-01

A FORTRAN program for calculating reflector antenna radiation patterns was rewritten and extended to include reflectors composed of a number of panels. These individual panels must be analytic surfaces. The theoretical foundation for the program is as follows: Geometrical optics techniques are used to trace rays from a feed antenna to the reflector surface and back to a mathematical plane just in front of the reflector. The resulting tangential electric field distribution, assumed to be the only source of forward radiation, is integrated numerically to calculate the radiation pattern for a desired set of angles. When the reflector is composed of more than one panel, each panel is treated as a separated antenna, the ray-tracing procedure and integration being repeated for each panel. The results of the individual aperture plane integrations are stored and summed to yield the relative electric field strength over the angles of interest. An example and several test cases are included to demonstrate the use of the program and verify the new method of computation.

A spectral measurement method for determining white OLED average junction temperatures

NASA Astrophysics Data System (ADS)

Zhu, Yiting; Narendran, Nadarajah

2016-09-01

The objective of this study was to investigate an indirect method of measuring the average junction temperature of a white organic light-emitting diode (OLED) based on temperature sensitivity differences in the radiant power emitted by individual emitter materials (i.e., "blue," "green," and "red"). The measured spectral power distributions (SPDs) of the white OLED as a function of temperature showed amplitude decrease as a function of temperature in the different spectral bands, red, green, and blue. Analyzed data showed a good linear correlation between the integrated radiance for each spectral band and the OLED panel temperature, measured at a reference point on the back surface of the panel. The integrated radiance ratio of the spectral band green compared to red, (G/R), correlates linearly with panel temperature. Assuming that the panel reference point temperature is proportional to the average junction temperature of the OLED panel, the G/R ratio can be used for estimating the average junction temperature of an OLED panel.

PMARC_12 - PANEL METHOD AMES RESEARCH CENTER, VERSION 12

NASA Technical Reports Server (NTRS)

Ashby, D. L.

1994-01-01

Panel method computer programs are software tools of moderate cost used for solving a wide range of engineering problems. The panel code PMARC_12 (Panel Method Ames Research Center, version 12) can compute the potential flow field around complex three-dimensional bodies such as complete aircraft models. PMARC_12 is a well-documented, highly structured code with an open architecture that facilitates modifications and the addition of new features. Adjustable arrays are used throughout the code, with dimensioning controlled by a set of parameter statements contained in an include file; thus, the size of the code (i.e. the number of panels that it can handle) can be changed very quickly. This allows the user to tailor PMARC_12 to specific problems and computer hardware constraints. In addition, PMARC_12 can be configured (through one of the parameter statements in the include file) so that the code's iterative matrix solver is run entirely in RAM, rather than reading a large matrix from disk at each iteration. This significantly increases the execution speed of the code, but it requires a large amount of RAM memory. PMARC_12 contains several advanced features, including internal flow modeling, a time-stepping wake model for simulating either steady or unsteady (including oscillatory) motions, a Trefftz plane induced drag computation, off-body and on-body streamline computations, and computation of boundary layer parameters using a two-dimensional integral boundary layer method along surface streamlines. In a panel method, the surface of the body over which the flow field is to be computed is represented by a set of panels. Singularities are distributed on the panels to perturb the flow field around the body surfaces. PMARC_12 uses constant strength source and doublet distributions over each panel, thus making it a low order panel method. Higher order panel methods allow the singularity strength to vary linearly or quadratically across each panel. Experience has shown that low order panel methods can provide nearly the same accuracy as higher order methods over a wide range of cases with significantly reduced computation times; hence, the low order formulation was adopted for PMARC_12. The flow problem is solved by modeling the body as a closed surface dividing space into two regions: the region external to the surface in which an unknown velocity potential exists representing the flow field of interest, and the region internal to the surface in which a known velocity potential (representing a fictitious flow) is prescribed as a boundary condition. Both velocity potentials are required to satisfy Laplace's equation. A surface integral equation for the unknown potential external to the surface can be written by applying Green's Theorem to the external region. Using the internal potential and zero flow through the surface as boundary conditions, the unknown potential external to the surface can be solved for. When the internal flow option, which allows the analysis of closed ducts, wind tunnels, and similar internal flow problems, is selected, the geometry is modeled such that the flow field of interest is inside the geometry and the fictitious flow is outside the geometry. Items such as wings, struts, or aircraft models can be included in the internal flow problem. The time-stepping wake model gives PMARC_12 the ability to model both steady and unsteady flow problems. The wake is convected downstream from the wake-separation line by the local velocity field. With each time step, a new row of wake panels is added to the wake at the wake-separation line. Time stepping can start from time t=0 (no initial wake) or from time t=t0 (an initial wake is specified). A wide range of motions can be prescribed, including constant rates of translation, constant rate of rotation about an arbitrary axis, oscillatory translation, and oscillatory rotation about any of the three coordinate axes. Investigators interested in a visual representation of the phenomenon they are studying with PMARC_12 may want to consider obtaining the program GVS (ARC-13361), the General Visualization System. GVS is a Silicon Graphics IRIS program which was created for the purpose of supporting the scientific visualization needs of PMARC_12. GVS is available separately from COSMIC. PMARC_12 is written in standard FORTRAN 77, with the exception of the NAMELIST extension used for input. This makes the code fairly machine independent. A compiler which supports the NAMELIST extension is required. The amount of free disk space and RAM memory required for PMARC_12 will vary depending on how the code is dimensioned using the parameter statements in the include file. The recommended minimum requirements are 20Mb of free disk space and 4Mb of RAM. PMARC_12 has been successfully implemented on a Macintosh II running System 6.0.7 or 7.0 (using MPW/Language Systems Fortran 3.0), a Sun SLC running SunOS 4.1.1, an HP 720 running HP-UX 8.07, an SGI IRIS running IRIX 4.0 (it will not run under IRIX 3.x.x without modifications), an IBM RS/6000 running AIX, a DECstation 3100 running ULTRIX, and a CRAY-YMP running UNICOS 6.0 or later. Due to its memory requirements, this program does not readily lend itself to implementation on MS-DOS based machines. The standard distribution medium for PMARC_12 is a set of three 3.5 inch 800K Macintosh format diskettes and one 3.5 inch 1.44Mb Macintosh format diskette which contains an electronic copy of the documentation in MS Word 5.0 format for the Macintosh. Alternate distribution media and formats are available upon request, but these will not include the electronic version of the document. No executables are included on the distribution media. This program is an update to PMARC version 11, which was released in 1989. PMARC_12 was released in 1993. It is available only for use by United States citizens.

Thermostructural Behavior of a Hypersonic Aircraft Sandwich Panel Subjected to Heating on One Side

NASA Technical Reports Server (NTRS)

Ko, William L.

1997-01-01

Thermostructural analysis was performed on a heated titanium honeycomb-core sandwich panel. The sandwich panel was supported at its four edges with spar-like substructures that acted as heat sinks, which are generally not considered in the classical analysis. One side of the panel was heated to high temperature to simulate aerodynamic heating during hypersonic flight. Two types of surface heating were considered: (1) flat-temperature profile, which ignores the effect of edge heat sinks, and (2) dome-shaped-temperature profile, which approximates the actual surface temperature distribution associated with the existence of edge heat sinks. The finite-element method was used to calculate the deformation field and thermal stress distributions in the face sheets and core of the sandwich panel. The detailed thermal stress distributions in the sandwich panel are presented, and critical stress regions are identified. The study shows how the magnitudes of those critical stresses and their locations change with different heating and edge conditions. This technical report presents comprehensive, three-dimensional graphical displays of thermal stress distributions in every part of a titanium honeycomb-core sandwich panel subjected to hypersonic heating on one side. The plots offer quick visualization of the structural response of the panel and are very useful for hot structures designers to identify the critical stress regions.

NASA Langley developments in response calculations needed for failure and life prediction

NASA Technical Reports Server (NTRS)

Housner, Jerrold M.

1993-01-01

NASA Langley developments in response calculations needed for failure and life predictions are discussed. Topics covered include: structural failure analysis in concurrent engineering; accuracy of independent regional modeling demonstrated on classical example; functional interface method accurately joins incompatible finite element models; interface method for insertion of local detail modeling extended to curve pressurized fuselage window panel; interface concept for joining structural regions; motivation for coupled 2D-3D analysis; compression panel with discontinuous stiffener coupled 2D-3D model and axial surface strains at the middle of the hat stiffener; use of adaptive refinement with multiple methods; adaptive mesh refinement; and studies on quantity effect of bow-type initial imperfections on reliability of stiffened panels.

An intelligent system for real time automatic defect inspection on specular coated surfaces

NASA Astrophysics Data System (ADS)

Li, Jinhua; Parker, Johné M.; Hou, Zhen

2005-07-01

Product visual inspection is still performed manually or semi automatically in most industries from simple ceramic tile grading to complex automotive body panel paint defect and surface quality inspection. Moreover, specular surfaces present additional challenge to conventional vision systems due to specular reflections, which may mask the true location of objects and lead to incorrect measurements. There are some sophisticated visual inspection methods developed in recent years. Unfortunately, most of them are highly computational. Systems built on those methods are either inapplicable or very costly to achieve real time inspection. In this paper, we describe an integrated low-cost intelligent system developed to automatically capture, extract, and segment defects on specular surfaces with uniform color coatings. The system inspects and locates regular surface defects with lateral dimensions as small as a millimeter. The proposed system is implemented on a group of smart cameras using its on-board processing ability to achieve real time inspection. The experimental results on real test panels demonstrate the effectiveness and robustness of proposed system.

Influence of extractives on bonding properties of white and southern red oak

Treesearch

Mon-Lin Kuo; Daniel DiCarlo; Chung-Yun Hse

1984-01-01

White and southern red oak veneer were subjected to four methods of drying followed by five surface treatments. The four drying methods were mill drying at 350°F, laboratory drying at 350 and 212°F, and air drying. The five surface treatments were no treatment, surface scraping, soaking and dipping in 1% NaOH aqueous solution, and water extraction. Plywood panels were...

Development of the triplet singularity for the analysis of wings and bodies in supersonic flow

NASA Technical Reports Server (NTRS)

Woodward, F. A.

1981-01-01

A supersonic triplet singularity was developed which eliminates internal waves generated by panels having supersonic edges. The triplet is a linear combination of source and vortex distributions which gives directional properties to the perturbation flow field surrounding the panel. The theoretical development of the triplet singularity is described together with its application to the calculation of surface pressures on wings and bodies. Examples are presented comparing the results of the new method with other supersonic methods and with experimental data.

Method and apparatus for manufacturing high-accuracy radio telescope reflector panels

NASA Astrophysics Data System (ADS)

Bosma, Marinus B.

1998-07-01

This article covers the manufacturing of aluminum reflector panels for submillimeter radio astronomy. The first part involves the general construction and application of a machine custom designed and built to do this. The second is a discussion of the software and execution of method to actually produce the reflectors for the Smithsonian Astrophysical Observatories Submillimeter Array (SMA). The reflective surface of each panel is contoured both radially and circularly by oscillating a platen supporting the panel about a fixed axis relative to a tool which is fixed during platen oscillation. The tool is repositionable between oscillations along an x axis to achieve the radial contour and along a z axis to achieve the desired parabolic or spherical contour. Contrary to the normal contouring of such a surface with a 5- axis CNC machine, tool positioning along either axis is independent of tool location along the other axis, simplifying the machine structure as well as its computerized operation. A unique hinge is provided to restrain the platen in a radial direction while allowing floating action of the platen on an air cushion during its oscillation. These techniques and the equipment are documented in U.S. Patent No. 5477602.

Steady and unsteady aerodynamic forces from the SOUSSA surface-panel method for a fighter wing with tip missile and comparison with experiment and PANAIR

NASA Technical Reports Server (NTRS)

Cunningham, Herbert J.

1987-01-01

The body surface-panel method SOUSSA is applied to calculate steady and unsteady lift and pitching moment coefficients on a thin fighter-type wing model with and without a tip-mounted missile. Comparisons are presented with experimental results and with PANAIR and PANAIR-related calculations for Mach numbers from 0.6 to 0.9. In general the SOUSSA program, the experiments, and the PANAIR (and related) programs give lift and pitching-moment results which agree at least fairly well, except for the unsteady clean-wing experimental moment and the unsteady moment on the wing tip body calculated by a PANAIR-predecessor program at a Mach number of 0.8.

Method for producing micro heat panels

NASA Technical Reports Server (NTRS)

Camarda, Charles J. (Inventor); Peterson, George P. (Inventor); Rummler, Donald R. (Inventor)

1997-01-01

Flat or curved micro heat pipe panels are fabricated by arranging essentially parallel filaments in the shape of the desired panel. The configuration of the filaments corresponds to the desired configuration of the tubes that will constitute the heat pipes. A thermally conductive material is then deposited on and around the filaments to fill in the desired shape of the panel. The filaments are then removed, leaving tubular passageways of the desired configuration and surface texture in the material. The tubes are then filled with a working fluid and sealed. Composite micro heat pipe laminates are formed by layering individual micro heat pipe panels and bonding them to each other to form a single structure. The layering sequence of the micro heat pipe panels can be tailored to transport heat preferentially in specific directions as desired for a particular application.

Micro Dot Patterning on the Light Guide Panel Using Powder Blasting

PubMed Central

Jang, Ho Su; Cho, Myeong Woo; Park, Dong Sam

2008-01-01

This study is to develop a micromachining technology for a light guide panel(LGP) mold, whereby micro dot patterns are formed on a LGP surface by a single injection process instead of existing screen printing processes. The micro powder blasting technique is applied to form micro dot patterns on the LGP mold surface. The optimal conditions for masking, laminating, exposure, and developing processes to form the micro dot patterns are first experimentally investigated. A LGP mold with masked micro patterns is then machined using the micro powder blasting method and the machinability of the micro dot patterns is verified. A prototype LGP is test- injected using the developed LGP mold and a shape analysis of the patterns and performance testing of the injected LGP are carried out. As an additional approach, matte finishing, a special surface treatment method, is applied to the mold surface to improve the light diffusion characteristics, uniformity and brightness of the LGP. The results of this study show that the applied powder blasting method can be successfully used to manufacture LGPs with micro patterns by just single injection using the developed mold and thereby replace existing screen printing methods. PMID:27879740

The directivity of the sound radiation from panels and openings.

PubMed

Davy, John L

2009-06-01

This paper presents a method for calculating the directivity of the radiation of sound from a panel or opening, whose vibration is forced by the incidence of sound from the other side. The directivity of the radiation depends on the angular distribution of the incident sound energy in the room or duct in whose wall or end the panel or opening occurs. The angular distribution of the incident sound energy is predicted using a model which depends on the sound absorption coefficient of the room or duct surfaces. If the sound source is situated in the room or duct, the sound absorption coefficient model is used in conjunction with a model for the directivity of the sound source. For angles of radiation approaching 90 degrees to the normal to the panel or opening, the effect of the diffraction by the panel or opening, or by the finite baffle in which the panel or opening is mounted, is included. A simple empirical model is developed to predict the diffraction of sound into the shadow zone when the angle of radiation is greater than 90 degrees to the normal to the panel or opening. The method is compared with published experimental results.

Implementing and testing a panel-based method for modeling acoustic scattering from CFD input

NASA Astrophysics Data System (ADS)

Swift, S. Hales

Exposure of sailors to high levels of noise in the aircraft carrier deck environment is a problem that has serious human and economic consequences. A variety of approaches to quieting exhausting jets from high-performance aircraft are undergoing development. However, testing of noise abatement solutions at full-scale may be prohibitively costly when many possible nozzle treatments are under consideration. A relatively efficient and accurate means of predicting the noise levels resulting from engine-quieting technologies at personnel locations is needed. This is complicated by the need to model both the direct and the scattered sound field in order to determine the resultant spectrum and levels. While the direct sound field may be obtained using CFD plus surface integral methods such as the Ffowcs-Williams Hawkings method, the scattered sound field is complicated by its dependence on the geometry of the scattering surface--the aircraft carrier deck, aircraft control surfaces and other nearby structures. In this work, a time-domain boundary element method, or TD-BEM, (sometimes referred to in terms of source panels) is proposed and developed that takes advantage of and offers beneficial effects for the substantial planar components of the aircraft carrier deck environment and uses pressure gradients as its input. This method is applied to and compared with analytical results for planar surfaces, corners and spherical surfaces using an analytic point source as input. The method can also accept input from CFD data on an acoustic data surface by using the G1A pressure gradient formulation to obtain pressure gradients on the surface from the flow variables contained on the acoustic data surface. The method is also applied to a planar scattering surface characteristic of an aircraft carrier flight deck with an acoustic data surface from a supersonic jet large eddy simulation, or LES, as input to the scattering model. In this way, the process for modeling the complete sound field (assuming the availability of an acoustic data surface from a time-realized numerical simulation of the jet flow field) is outlined for a realistic group of source location, scattering surface location and observer locations. The method was able to successfully model planar cases, corners and spheres with a level of error that is low enough for some engineering purposes. Significant benefits were realized for fully planar surfaces including high parallelizability and avoidance of interaction between portions of the paneled boundary. When the jet large eddy simulation case was considered the method was able to capture a substantial portion of the spectrum including the peak frequency region and a majority of the spectral energy with good fidelity.

A two-dimensional iterative panel method and boundary layer model for bio-inspired multi-body wings

NASA Astrophysics Data System (ADS)

Blower, Christopher J.; Dhruv, Akash; Wickenheiser, Adam M.

2014-03-01

The increased use of Unmanned Aerial Vehicles (UAVs) has created a continuous demand for improved flight capabilities and range of use. During the last decade, engineers have turned to bio-inspiration for new and innovative flow control methods for gust alleviation, maneuverability, and stability improvement using morphing aircraft wings. The bio-inspired wing design considered in this study mimics the flow manipulation techniques performed by birds to extend the operating envelope of UAVs through the installation of an array of feather-like panels across the airfoil's upper and lower surfaces while replacing the trailing edge flap. Each flap has the ability to deflect into both the airfoil and the inbound airflow using hinge points with a single degree-of-freedom, situated at 20%, 40%, 60% and 80% of the chord. The installation of the surface flaps offers configurations that enable advantageous maneuvers while alleviating gust disturbances. Due to the number of possible permutations available for the flap configurations, an iterative constant-strength doublet/source panel method has been developed with an integrated boundary layer model to calculate the pressure distribution and viscous drag over the wing's surface. As a result, the lift, drag and moment coefficients for each airfoil configuration can be calculated. The flight coefficients of this numerical method are validated using experimental data from a low speed suction wind tunnel operating at a Reynolds Number 300,000. This method enables the aerodynamic assessment of a morphing wing profile to be performed accurately and efficiently in comparison to Computational Fluid Dynamics methods and experiments as discussed herein.

Surface properties of thermally treated composite wood panels

NASA Astrophysics Data System (ADS)

Croitoru, Catalin; Spirchez, Cosmin; Lunguleasa, Aurel; Cristea, Daniel; Roata, Ionut Claudiu; Pop, Mihai Alin; Bedo, Tibor; Stanciu, Elena Manuela; Pascu, Alexandru

2018-04-01

Composite finger-jointed spruce and oak wood panels have been thermally treated under standard pressure and oxygen content conditions at two different temperatures, 180 °C and respectively 200 °C for short time periods (3 and 5 h). Due to the thermally-aided chemical restructuration of the wood components, a decrease in water uptake and volumetric swelling values with up to 45% for spruce and 35% for oak have been registered, comparing to the reference samples. In relation to water resistance, a 15% increase of the dispersive component of the surface energy has been registered for the thermal-treated spruce panels, which impedes water spreading on the surface. The thermal-treated wood presents superior resistance to accelerated UV exposure and subsequently, with up to 10% higher Brinell hardness values than reference wood. The proposed thermal treatment improves the durability of the finger-jointed wood through a more economically and environmental friendly method than traditional impregnation, with minimal degradative impact on the structural components of wood.

Updated Panel-Method Computer Program

NASA Technical Reports Server (NTRS)

Ashby, Dale L.

1995-01-01

Panel code PMARC_12 (Panel Method Ames Research Center, version 12) computes potential-flow fields around complex three-dimensional bodies such as complete aircraft models. Contains several advanced features, including internal mathematical modeling of flow, time-stepping wake model for simulating either steady or unsteady motions, capability for Trefftz computation of drag induced by plane, and capability for computation of off-body and on-body streamlines, and capability of computation of boundary-layer parameters by use of two-dimensional integral boundary-layer method along surface streamlines. Investigators interested in visual representations of phenomena, may want to consider obtaining program GVS (ARC-13361), General visualization System. GVS is Silicon Graphics IRIS program created to support scientific-visualization needs of PMARC_12. GVS available separately from COSMIC. PMARC_12 written in standard FORTRAN 77, with exception of NAMELIST extension used for input.

24 CFR 3280.406 - Air chamber test method for certification and qualification of formaldehyde emission levels.

Code of Federal Regulations, 2010 CFR

2010-04-01

... particleboard is produced or surface-finished, whichever is later, the panels must be dead-stacked or air-tight... with the Standard Test Method for Determining Formaldehyde Levels from Wood Products Under Defined Test...

Predicting aerodynamic characteristics of vortical flows on three-dimensional configurations using a surface-singularity panel method

NASA Technical Reports Server (NTRS)

Maskew, B.

1983-01-01

A general low-order surface-singularity panel method is used to predict the aerodynamic characteristics of a problem where a wing-tip vortex from one wing closely interacts with an aft mounted wing in a low Reynolds Number flow; i.e., 125,000. Nonlinear effects due to wake roll-up and the influence of the wings on the vortex path are included in the calculation by using a coupled iterative wake relaxation scheme. The interaction also affects the wing pressures and boundary layer characteristics: these effects are also considered using coupled integral boundary layer codes and preliminary calculations using free vortex sheet separation modelling are included. Calculated results are compared with water tunnel experimental data with generally remarkably good agreement.

Method for applying photographic resists to otherwise incompatible substrates

NASA Technical Reports Server (NTRS)

Fuhr, W. (Inventor)

1981-01-01

A method for applying photographic resists to otherwise incompatible substrates, such as a baking enamel paint surface, is described wherein the uncured enamel paint surface is coated with a non-curing lacquer which is, in turn, coated with a partially cured lacquer. The non-curing lacquer adheres to the enamel and a photo resist material satisfactorily adheres to the partially cured lacquer. Once normal photo etching techniques are employed the lacquer coats can be easily removed from the enamel leaving the photo etched image. In the case of edge lighted instrument panels, a coat of uncured enamel is placed over the cured enamel followed by the lacquer coats and the photo resists which is exposed and developed. Once the etched uncured enamel is cured, the lacquer coats are removed leaving an etched panel.

Study on a novel panel support concept for radio telescopes with active surface

NASA Astrophysics Data System (ADS)

Yang, Dehua; Zhou, Guohua; Okoh, Daniel; Li, Guoping; Cheng, Jingquan

2010-07-01

Generally, panels of radio telescopes are mainly shaped in trapezoid and each is supported/positioned by four adjustors beneath its vertexes. Such configuration of panel supporting system is essentially hyper-static, and the panel is overconstrained from a kinematic point of view. When the panel is to be adjusted and/or actuated, it will suffer stress from its adjusters and hence its shape is to be distorted. This situation is not desirable for high precision panels, such as glass based panels especially used for sub-millimeter and shorter wavelength telescopes with active optics/active panel technology. This paper began with a general overview of panel patterns and panel supports of existing radio telescopes. Thereby, we proposed a preferable master-slave active surface concept for triangular and/or hexagonal panel pattern. In addition, we carry out panel error sensitivity analysis for all the 6 degrees of freedom (DOF) of a panel to identify what DOFs are most sensitive for an active surface. And afterwards, based on the error sensitivity analysis, we suggested an innovative parallel-series concept hexapod well fitted for an active panel to correct for all of its 6 rigid errors. A demonstration active surface using the master-slave concept and the hexapod manifested a great save in cost, where only 486 precision actuators are needed for 438 panels, which is 37% of those actuators needed by classic segmented mirror active optics. Further, we put forward a swaying-arm based design concept for the related connecting joints between panels, which ensures that all the panels attached on to it free from over-constraints when they are positioned and/or actuated. Principle and performance of the swaying-arm connecting mechanism are elaborated before a practical cablemesh based prototype active surface is presented with comprehensive finite element analysis and simulation.

Prediction of light aircraft interior sound pressure level using the room equation

NASA Technical Reports Server (NTRS)

Atwal, M.; Bernhard, R.

1984-01-01

The room equation is investigated for predicting interior sound level. The method makes use of an acoustic power balance, by equating net power flow into the cabin volume to power dissipated within the cabin using the room equation. The sound power level transmitted through the panels was calculated by multiplying the measured space averaged transmitted intensity for each panel by its surface area. The sound pressure level was obtained by summing the mean square sound pressures radiated from each panel. The data obtained supported the room equation model in predicting the cabin interior sound pressure level.

On the balancing of structural and acoustic performance of a sandwich panel based on topology, property, and size optimization

NASA Astrophysics Data System (ADS)

Cameron, Christopher J.; Lind Nordgren, Eleonora; Wennhage, Per; Göransson, Peter

2014-06-01

Balancing structural and acoustic performance of a multi-layered sandwich panel is a formidable undertaking. Frequently the gains achieved in terms of reduced weight, still meeting the structural design requirements, are lost by the changes necessary to regain acceptable acoustic performance. To alleviate this, a design method for a multifunctional load bearing vehicle body panel is proposed which attempts to achieve a balance between structural and acoustic performance. The approach is based on numerical modelling of the structural and acoustic behaviour in a combined topology, size, and property optimization in order to achieve a three dimensional optimal distribution of structural and acoustic foam materials within the bounding surfaces of a sandwich panel. In particular the effects of the coupling between one of the bounding surface face sheets and acoustic foam are examined for its impact on both the structural and acoustic overall performance of the panel. The results suggest a potential in introducing an air gap between the acoustic foam parts and one of the face sheets, provided that the structural design constraints are met without prejudicing the layout of the different foam types.

METHODS OF TREATMENT OF COMPLEX SURFACES ON METAL CUTTING MACHINES (CHAPTERS 1 AND 12),

DTIC Science & Technology

FORGING, MOLDINGS, MANDRELS, MARINE PROPELLERS, AERIAL PROPELLERS, TURBINE BLADES, ABRASIVES, IMPELLERS, AIRCRAFT PANELS, METAL PLATES, CAMS, ELECTROEROSIVE MACHINING, CHEMICAL MILLING, MAGNETOSTRICTIVE ELEMENTS, USSR.

Surface Sampling-Based Decontamination Studies and Protocol for Determining Sporicidal Efficacy of Gaseous Fumigants on Military-Relevant Surfaces

DTIC Science & Technology

2008-09-01

related scenarios related to US armed forces around the world . In the civilian setting, complete decontamination is the only accepted criteria before a...observation, a door for sample introduction, and four ports on the front panel for sensor placement. All glass surfaces were covered when used with CD gas...1999, 281, 1735-1745. 9. AOAC International Method 966.04; Official Methods of Analisis , 21’t ed.; Chapter 6: AOAC International: Gaithersburg, MD

Shin-Etsu super-high-flat substrate for FPD panel photomask

NASA Astrophysics Data System (ADS)

Ishitsuka, Youkou; Harada, Daijitsu; Watabe, Atsushi; Takeuchi, Masaki

2017-07-01

Recently, high-resolution exposure machine has been developed for production of high-definition (HD) panels, and higher-flat photomask substrates for FPD is being expected for panel makers to produce HD panels. In this presentation, we introduce about Shin-Etsu's advanced technique of producing super-high-flat photomask substrates. Shin-Etsu has developed surface polishing and planarization technology with No.1-quality-IC photomask substrates. Our most advanced IC photomask substrates have gained the highest estimation and appreciation from our customers because of their surface quality (non-defect surface without sub-0.1um size defects) and ultimate flatness (sub-0.1um order having achieved). By scaling up those IC photomask substrate technologies and developing unique large-size processing technologies, we have achieved creating high-flat large substrates, even G10-photomask size as well as regular G6-G8 photomask size. The core technology is that the surface shape of the substrate is completely controlled by the unique method. For example, we can regularly produce a substrate with its flatness of triple 5ums; front side flatness, back side flatness and total thickness variation are all less than 5μm. Furthermore, we are able to supply a substrate with its flatness of triple 3ums for G6-photomask size advanced grade, believed to be needed in near future.

Submerged combustion melting processes for producing glass and similar materials, and systems for carrying out such processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Charbonneau, Mark William

Processes of controlling submerged combustion melters, and systems for carrying out the methods. One process includes feeding vitrifiable material into a melter vessel, the melter vessel including a fluid-cooled refractory panel in its floor, ceiling, and/or sidewall, and heating the vitrifiable material with a burner directing combustion products into the melting zone under a level of the molten material in the zone. Burners impart turbulence to the molten material in the melting zone. The fluid-cooled refractory panel is cooled, forming a modified panel having a frozen or highly viscous material layer on a surface of the panel facing the moltenmore » material, and a sensor senses temperature of the modified panel using a protected thermocouple positioned in the modified panel shielded from direct contact with turbulent molten material. Processes include controlling the melter using the temperature of the modified panel. Other processes and systems are presented.« less

21 CFR 660.3 - Reference panel.

Code of Federal Regulations, 2012 CFR

2012-04-01

... ADDITIONAL STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Antibody to Hepatitis B Surface Antigen § 660.3 Reference panel. A Reference Hepatitis B Surface Antigen Panel shall be obtained from the Center... shall be used for determining the potency and specificity of Antibody to Hepatitis B Surface Antigen...

21 CFR 660.3 - Reference panel.

Code of Federal Regulations, 2013 CFR

2013-04-01

... ADDITIONAL STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Antibody to Hepatitis B Surface Antigen § 660.3 Reference panel. A Reference Hepatitis B Surface Antigen Panel shall be obtained from the Center... shall be used for determining the potency and specificity of Antibody to Hepatitis B Surface Antigen...

21 CFR 660.3 - Reference panel.

Code of Federal Regulations, 2011 CFR

2011-04-01

... STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Antibody to Hepatitis B Surface Antigen § 660.3 Reference panel. A Reference Hepatitis B Surface Antigen Panel shall be obtained from the Center for... used for determining the potency and specificity of Antibody to Hepatitis B Surface Antigen. [40 FR...

21 CFR 660.3 - Reference panel.

Code of Federal Regulations, 2014 CFR

2014-04-01

... ADDITIONAL STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Antibody to Hepatitis B Surface Antigen § 660.3 Reference panel. A Reference Hepatitis B Surface Antigen Panel shall be obtained from the Center... shall be used for determining the potency and specificity of Antibody to Hepatitis B Surface Antigen...

21 CFR 660.3 - Reference panel.

Code of Federal Regulations, 2010 CFR

2010-04-01

... ADDITIONAL STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Antibody to Hepatitis B Surface Antigen § 660.3 Reference panel. A Reference Hepatitis B Surface Antigen Panel shall be obtained from the Center... shall be used for determining the potency and specificity of Antibody to Hepatitis B Surface Antigen...

Frame Shift/warp Compensation for the ARID Robot System

NASA Technical Reports Server (NTRS)

Latino, Carl D.

1991-01-01

The Automatic Radiator Inspection Device (ARID) is a system aimed at automating the tedious task of inspecting orbiter radiator panels. The ARID must have the ability to aim a camera accurately at the desired inspection points, which are in the order of 13,000. The ideal inspection points are known; however, the panel may be relocated due to inaccurate parking and warpage. A method of determining the mathematical description of a translated as well as a warped surface by accurate measurement of only a few points on this surface is developed here. The method uses a linear warp model whose effect is superimposed on the rigid body translation. Due to the angles involved, small angle approximations are possible, which greatly reduces the computational complexity. Given an accurate linear warp model, all the desired translation and warp parameters can be obtained by knowledge of the ideal locations of four fiducial points and the corresponding measurements of these points on the actual radiator surface. The method uses three of the fiducials to define a plane and the fourth to define the warp. Given this information, it is possible to determine a transformation that will enable the ARID system to translate any desired inspection point on the ideal surface to its corresponding value on the actual surface.

Panel regressions to estimate low-flow response to rainfall variability in ungaged basins

USGS Publications Warehouse

Bassiouni, Maoya; Vogel, Richard M.; Archfield, Stacey A.

2016-01-01

Multicollinearity and omitted-variable bias are major limitations to developing multiple linear regression models to estimate streamflow characteristics in ungaged areas and varying rainfall conditions. Panel regression is used to overcome limitations of traditional regression methods, and obtain reliable model coefficients, in particular to understand the elasticity of streamflow to rainfall. Using annual rainfall and selected basin characteristics at 86 gaged streams in the Hawaiian Islands, regional regression models for three stream classes were developed to estimate the annual low-flow duration discharges. Three panel-regression structures (random effects, fixed effects, and pooled) were compared to traditional regression methods, in which space is substituted for time. Results indicated that panel regression generally was able to reproduce the temporal behavior of streamflow and reduce the standard errors of model coefficients compared to traditional regression, even for models in which the unobserved heterogeneity between streams is significant and the variance inflation factor for rainfall is much greater than 10. This is because both spatial and temporal variability were better characterized in panel regression. In a case study, regional rainfall elasticities estimated from panel regressions were applied to ungaged basins on Maui, using available rainfall projections to estimate plausible changes in surface-water availability and usable stream habitat for native species. The presented panel-regression framework is shown to offer benefits over existing traditional hydrologic regression methods for developing robust regional relations to investigate streamflow response in a changing climate.

Panel regressions to estimate low-flow response to rainfall variability in ungaged basins

NASA Astrophysics Data System (ADS)

Bassiouni, Maoya; Vogel, Richard M.; Archfield, Stacey A.

2016-12-01

Multicollinearity and omitted-variable bias are major limitations to developing multiple linear regression models to estimate streamflow characteristics in ungaged areas and varying rainfall conditions. Panel regression is used to overcome limitations of traditional regression methods, and obtain reliable model coefficients, in particular to understand the elasticity of streamflow to rainfall. Using annual rainfall and selected basin characteristics at 86 gaged streams in the Hawaiian Islands, regional regression models for three stream classes were developed to estimate the annual low-flow duration discharges. Three panel-regression structures (random effects, fixed effects, and pooled) were compared to traditional regression methods, in which space is substituted for time. Results indicated that panel regression generally was able to reproduce the temporal behavior of streamflow and reduce the standard errors of model coefficients compared to traditional regression, even for models in which the unobserved heterogeneity between streams is significant and the variance inflation factor for rainfall is much greater than 10. This is because both spatial and temporal variability were better characterized in panel regression. In a case study, regional rainfall elasticities estimated from panel regressions were applied to ungaged basins on Maui, using available rainfall projections to estimate plausible changes in surface-water availability and usable stream habitat for native species. The presented panel-regression framework is shown to offer benefits over existing traditional hydrologic regression methods for developing robust regional relations to investigate streamflow response in a changing climate.

The prediction of pressure distributions on an arrow-wing configuration including the effect of camber, twist, and a wing fin

NASA Technical Reports Server (NTRS)

Bobbitt, P. J.; Manro, M. E.; Kulfan, R. M.

1980-01-01

Wind tunnel tests of an arrow wing body configuration consisting of flat, twisted, and cambered twisted wings were conducted at Mach numbers from 0.40 to 2.50 to provide an experimental data base for comparison with theoretical methods. A variety of leading and trailing edge control surface deflections were included in these tests, and in addition, the cambered twisted wing was tested with an outboard vertical fin to determine its effect on wing and control surface loads. Theory experiment comparisons show that current state of the art linear and nonlinear attached flow methods were adequate at small angles of attack typical of cruise conditions. The incremental effects of outboard fin, wing twist, and wing camber are most accurately predicted by the advanced panel method PANAIR. Results of the advanced panel separated flow method, obtained with an early version of the program, show promise that accurate detailed pressure predictions may soon be possible for an aeroelasticity deformed wing at high angles of attack.

Sound-proof Sandwich Panel Design via Metamaterial Concept

NASA Astrophysics Data System (ADS)

Sui, Ni

Sandwich panels consisting of hollow core cells and two face-sheets bonded on both sides have been widely used as lightweight and strong structures in practical engineering applications, but with poor acoustic performance especially at low frequency regime. Basic sound-proof methods for the sandwich panel design are spontaneously categorized as sound insulation and sound absorption. Motivated by metamaterial concept, this dissertation presents two sandwich panel designs without sacrificing weight or size penalty: A lightweight yet sound-proof honeycomb acoustic metamateiral can be used as core material for honeycomb sandwich panels to block sound and break the mass law to realize minimum sound transmission; the other sandwich panel design is based on coupled Helmholtz resonators and can achieve perfect sound absorption without sound reflection. Based on the honeycomb sandwich panel, the mechanical properties of the honeycomb core structure were studied first. By incorporating a thin membrane on top of each honeycomb core, the traditional honeycomb core turns into honeycomb acoustic metamaterial. The basic theory for such kind of membrane-type acoustic metamaterial is demonstrated by a lumped model with infinite periodic oscillator system, and the negative dynamic effective mass density for clamped membrane is analyzed under the membrane resonance condition. Evanescent wave mode caused by negative dynamic effective mass density and impedance methods are utilized to interpret the physical phenomenon of honeycomb acoustic metamaterials at resonance. The honeycomb metamaterials can extraordinarily improve low-frequency sound transmission loss below the first resonant frequency of the membrane. The property of the membrane, the tension of the membrane and the numbers of attached membranes can impact the sound transmission loss, which are observed by numerical simulations and validated by experiments. The sandwich panel which incorporates the honeycomb metamateiral as the core material maintains the mechanical property and yields a sound transmission loss that is consistently greater than 50 dB at low frequencies. Furthermore, the absorption property of the proposed honeycomb sandwich panel was experimentally studied. The honeycomb sandwich panel shows an excellent sound absorbing performance at high frequencies by using reinforced glass fiber without adding too much mass. The effect of the panel size and the stiffness of the grid-like frame effect of the honeycomb sandwich structures on sound transmission are discussed lastly. For the second sound-proof sandwich panel design, each unit cell of the sandwich panel is replaced by a Helmholtz resonator by perforating a small hole on the top face sheet. A perfect sound absorber sandwich panel with coupled Helmholtz resonators is proposed by two types: single identical Helmholtz resonator in each unit cell and dual Helmholtz resonators with different orifices, arranged in each cell arranged periodically. The soundproof sandwich panel is modelled as a panel embedded in rigid panel and assumed as a semiinfinite space with hard boundary condition. The net/mutual impedance model is first proposed and derived by solving Kirchhoff-Helmholtz integral by using the Green's function. The thermal-viscous energy dissipation at the thermal boundary layer dominates the total energy consumed. Two types of perfect sound absorber sandwich panel are designed in the last part. Two theoretical methods: the average energy and the equivalent surface impedance method are used to predict sound absorption performance. The geometry for perfect sound absorber sandwich panel at a target frequency can be obtained when the all the Helmholtz resonators are at resonance and the surface impedance of the sandwich panel matches the air impedance. The bandwidth for the identical sandwich panel mainly depends on the neck radius. The absorptive property of the dual Helmholtz resonators type of sandwich panel is studied by investigating the coupling effects between HRs. The theoretical results can be verified by numerical simulations through finite element method. The absorption bandwidth can be tuned by incorporating more HRs in each unit cell. Both sound-proof sandwich panel designs possess extraordinary acoustic performance for noise reduction at low frequency range with sub-wavelength structures. The sound absorber panel design can also achieve broadband sound attenuation at low frequencies.

Silica powders for powder evacuated thermal insulating panel and method

DOEpatents

Harris, Michael T.; Basaran, Osman A.; Kollie, Thomas G.; Weaver, Fred J.

1996-01-01

A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm.sup.3 and an external surface area in the range of about 90 to 600 m.sup.2/ g is described. The silica powders are prepared by reacting a tetraakyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders.

Silica powders for powder evacuated thermal insulating panel and method

DOEpatents

Harris, Michael T.; Basaran, Osman A.; Kollie, Thomas G.; Weaver, Fred J.

1994-01-01

A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm.sup.3 and an external surface area in the range of about 90 to 600 m.sup.2 /g is described. The silica powders are prepared by reacting a tetraakyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders.

Silica powders for powder evacuated thermal insulating panel and method

DOEpatents

Harris, Michael T.; Basaran, Osman A.; Kollie, Thomas G.; Weaver, Fred J.

1995-01-01

A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm.sup.3 and an external surface area in the range of about 90 to 600 m.sup.2/ g is described. The silica powders are prepared by reacting a tetraakyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders.

Silica powders for powder evacuated thermal insulating panel and method

DOEpatents

Harris, M.T.; Basaran, O.A.; Kollie, T.G.; Weaver, F.J.

1996-01-02

A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm{sup 3} and an external surface area in the range of about 90 to 600 m{sup 2}/g is described. The silica powders are prepared by reacting a tetraalkyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders. 2 figs.

Effect of various fire retardants on surface roughness of plywood

Treesearch

Nadir Ayrilmis; Suleyman Korkut; Ercan Tanritanir; Jerrold E. Winandy; Salim Hiziroglu

2006-01-01

In this study the surface roughness of plywood treated with various fire retardants was investigated. Commercially manufactured veneer of Akaba wood (Tetraberlinia bifoliolata) was treated with borax, boric acid, monoammonium phosphate and diammonium phosphate, then experimental plywood panels were made from these veneer sheets. A stylus method was employed to evaluate...

Flow cytometry immunophenotyping in integrated diagnostics of patients with newly diagnosed cytopenia: one tube 10-color 14-antibody screening panel and 3-tube extensive panel for detection of MDS-related features.

PubMed

Porwit, A; Rajab, A

2015-05-01

Acute leukemia, myelodysplastic syndromes (MDS), myeloproliferative neoplasms and lymphomas are the most prevalent diagnoses in adults presenting with new onset cytopenia. Here, we describe two 10-color panels of surface markers (screening and comprehensive panel) applied at the Flow Cytometry Laboratory, University Health Network, Toronto, ON, Canada. A 10-color flow cytometry is applied using the stain-lyse-wash sample preparation method. In patients with <10% blasts and no clear involvement by hematological malignancy based on cytomorphological evaluation of bone marrow (BM) smear, the recently published one-tube 10-color 14-antibody screening panel is applied. This panel allows detection of major B- and T-cell abnormalities, enumeration of cells in blast region (CD45 dim), and gives insight into myeloid BM compartment, including calculation of four-parameter score for MDS-related abnormalities. In patients who present with ≥10 - <20% blasts in blood or BM smears, a comprehensive three-tube panel of surface markers is used up front. The analysis is focused on the detection of abnormal antigen expression patterns not seen in normal/reactive BM, according to the guidelines developed by International/European LeukemiaNet Working Group for Flow Cytometry in MDS. In patients with ≥20% blasts, an additional tube is added to allow the detection of cytoplasmic markers necessary to diagnose mixed phenotype acute leukemia. © 2015 John Wiley & Sons Ltd.

USSAERO computer program development, versions B and C

NASA Technical Reports Server (NTRS)

Woodward, F. A.

1980-01-01

Versions B and C of the unified subsonic and supersonic aerodynamic analysis program, USSAERO, are described. Version B incorporates a new symmetrical singularity method to provide improved surface pressure distributions on wings in subsonic flow. Version C extends the range of application of the program to include the analysis of multiple engine nacelles or finned external stores. In addition, nonlinear compressibility effects in high subsonic and supersonic flows are approximated using a correction based on the local Mach number at panel control points. Several examples are presented comparing the results of these programs with other panel methods and experimental data.

Panel positioning error and support mechanism for a 30-m THz radio telescope

NASA Astrophysics Data System (ADS)

Yang, De-Hua; Okoh, Daniel; Zhou, Guo-Hua; Li, Ai-Hua; Li, Guo-Ping; Cheng, Jing-Quan

2011-06-01

A 30-m TeraHertz (THz) radio telescope is proposed to operate at 200 μm with an active primary surface. This paper presents sensitivity analysis of active surface panel positioning errors with optical performance in terms of the Strehl ratio. Based on Ruze's surface error theory and using a Monte Carlo simulation, the effects of six rigid panel positioning errors, such as piston, tip, tilt, radial, azimuthal and twist displacements, were directly derived. The optical performance of the telescope was then evaluated using the standard Strehl ratio. We graphically illustrated the various panel error effects by presenting simulations of complete ensembles of full reflector surface errors for the six different rigid panel positioning errors. Study of the panel error sensitivity analysis revealed that the piston error and tilt/tip errors are dominant while the other rigid errors are much less important. Furthermore, as indicated by the results, we conceived of an alternative Master-Slave Concept-based (MSC-based) active surface by implementating a special Series-Parallel Concept-based (SPC-based) hexapod as the active panel support mechanism. A new 30-m active reflector based on the two concepts was demonstrated to achieve correction for all the six rigid panel positioning errors in an economically feasible way.

Laminar flow control SPF/08 feasibility demonstration

NASA Astrophysics Data System (ADS)

Ecklund, R. C.; Williams, N. R.

1981-10-01

The feasibility of applying superplastic forming/diffusion bonding (SPF/DB) technology to laminar flow control (LFC) system concepts was demonstrated. Procedures were developed to produce smooth, flat titanium panels, using thin -0.016 inch sheets, meeting LFC surface smoothness requirements. Two large panels 28 x 28 inches were fabricated as final demonstration articles. The first was flat on the top and bottom sides demonstrating the capability of the tooling and the forming and diffusion bonding procedures to produce flat, defect free surfaces. The second panel was configurated for LFC porous panel treatment by forming channels with dimpled projections on the top side. The projections were machined away leaving holes extending into the panel. A perforated titanium sheet was adhesively bonded over this surface to complete the LFC demonstration panel. The final surface was considered flat enough to meet LFC requirements for a jet transport aircraft in cruising flight.

Formulation of an improved smeared stiffener theory for buckling analysis of grid-stiffened composite panels

NASA Technical Reports Server (NTRS)

Jaunky, Navin; Knight, Norman F., Jr.; Ambur, Damodar R.

1995-01-01

A smeared stiffener theory for stiffened panels is presented that includes skin-stiffener interaction effects. The neutral surface profile of the skin-stiffener combination is developed analytically using the minimum potential energy principle and statics conditions. The skin-stiffener interaction is accounted for by computing the stiffness due to the stiffener and the skin in the skin-stiffener region about the neutral axis at the stiffener. Buckling load results for axially stiffened, orthogrid, and general grid-stiffened panels are obtained using the smeared stiffness combined with a Rayleigh-Ritz method and are compared with results from detailed finite element analyses.

Material development for laminar flow control wing panels

NASA Technical Reports Server (NTRS)

Meade, L. E.

1977-01-01

The absence of suitable porous materials or techniques for the economic perforation of surface materials has previously restricted the design of laminar flow control (LFC) wing panels to a consideration of mechanically slotted LFC surfaces. A description is presented of a program which has been conducted to exploit recent advances in materials and manufacturing technology for the fabrication of reliable porous or perforated LFC surface panels compatible with the requirements of subsonic transport aircraft. Attention is given to LFC design criteria, surface materials, surface concepts, the use of microporous composites, perforated composites, and perforated metal. The described program was successful in that fabrication processes were developed for producing predictable perforated panels both of composite and of metal.

An experimental investigation devoted to determine heat transfer characteristics in a radiant ceiling heating system

NASA Astrophysics Data System (ADS)

Koca, Aliihsan; Acikgoz, Ozgen; Çebi, Alican; Çetin, Gürsel; Dalkilic, Ahmet Selim; Wongwises, Somchai

2018-02-01

Investigations on heated ceiling method can be considered as a new research area in comparison to the common wall heating-cooling and cooled ceiling methods. In this work, heat transfer characteristics of a heated radiant ceiling system was investigated experimentally. There were different configurations for a single room design in order to determine the convective and radiative heat transfer rates. Almost all details on the arrangement of the test chamber, hydraulic circuit and radiant panels, the measurement equipment and experimental method including uncertainty analysis were revealed in detail indicating specific international standards. Total heat transfer amount from the panels were calculated as the sum of radiation to the unheated surfaces, convection to the air, and conduction heat loss from the backside of the panels. Integral expression of the view factors was calculated by means of the numerical evaluations using Matlab code. By means of this experimental chamber, the radiative, convective and total heat-transfer coefficient values along with the heat flux values provided from the ceiling to the unheated surrounding surfaces have been calculated. Moreover, the details of 28 different experimental case study measurements from the experimental chamber including the convective, radiative and total heat flux, and heat output results are given in a Table for other researchers to validate their theoretical models and empirical correlations.

Novel Composites for Wing and Fuselage Applications: Speedy Nonlinear Analysis of Postbuckled Panels in Shear (SNAPPS)

NASA Technical Reports Server (NTRS)

Sharp, Dave; Sobel, Larry

1997-01-01

A simple and rapid analysis method, consisting of a number of modular, 'strength-of-materials-type' models, is presented for predicting the nonlinear response and stiffener separation of postbuckled, flat, composite, shear panels. The analysis determines the maximum principal tensile stress in the skin surface layer under to toe. Failure is said to occur when this stress reaches the mean transverse tensile strength of the layer. The analysis methodology consists of a number of closed-form equations that can easily be used in a 'hand analysis. For expediency, they have been programmed into a preliminary design code called SNAPPS (Speedy Nonlinear Analysis of Postbuckled Panels in Shear), which rapidly predicts postbuckling response of the panel for each value of the applied shear load. SNAPPS response and failure predictions were found to agree well with test results for three panels with widely different geometries, laminates and stiffnesses. Design guidelines are given for increasing the load-carrying capacity of stiffened, composite shear panels.

Effects of post heat-treatment on surface characteristics and adhesive bonding performance of medium density fiberboard

Treesearch

Nadir Ayrilimis; Jerrold E. Winandy

2009-01-01

A series of commercially manufactured medium density fiberboard (MDF) panels were exposed to a post-manufacture heat-treatment at various temperatures and durations using a hot press and just enough pressure to ensure firm contact between the panel and the press platens. Post-manufacture heat-treatment improved surface roughness of the exterior MDF panels. Panels...

Cone calorimeter testing of foam core sandwich panels treated with intumescent paper underneath the veneer (FRV)

Treesearch

Mark A. Dietenberger; Ali Shalbafan; Johannes Welling

2017-01-01

Surfaces of novel foam core sandwich panels were adhered with intumescent fire‐retardant paper underneath the veneers (FRV) to improve their flammability properties. The panels were evaluated by means of cone calorimeter test (ASTM E 1354). Variables tested were different surface layer treatments, adhesives used for veneering, surface layer thicknesses, and processing...

Prediction of the optimum surface orientation angles to achieve maximum solar radiation using Particle Swarm Optimization in Sabha City Libya

NASA Astrophysics Data System (ADS)

Mansour, F. A.; Nizam, M.; Anwar, M.

2017-02-01

This research aims to predict the optimum surface orientation angles in solar panel installation to achieve maximum solar radiation. Incident solar radiation is calculated using koronakis mathematical model. Particle Swarm Optimization (PSO) is used as computational method to find optimum angle orientation for solar panel installation in order to get maximum solar radiation. A series of simulation has been carried out to calculate solar radiation based on monthly, seasonally, semi-yearly and yearly period. South-facing was calculated also as comparison of proposed method. South-facing considers azimuth of 0°. Proposed method attains higher incident predictions than South-facing that recorded 2511.03 kWh/m2for monthly. It were about 2486.49 kWh/m2, 2482.13 kWh/m2and 2367.68 kWh/m2 for seasonally, semi-yearly and yearly. South-facing predicted approximately 2496.89 kWh/m2, 2472.40 kWh/m2, 2468.96 kWh/m2, 2356.09 kWh/m2for monthly, seasonally, semi-yearly and yearly periods respectively. Semi-yearly is the best choice because it needs twice adjustments of solar panel in a year. Yet it considers inefficient to adjust solar panel position in every season or monthly with no significant solar radiation increase than semi-yearly and solar tracking device still considers costly in solar energy system. PSO was able to predict accurately with simple concept, easy and computationally efficient. It has been proven by finding the best fitness faster.

Panel Flutter Emulation Using a Few Concentrated Forces

NASA Astrophysics Data System (ADS)

Dhital, Kailash; Han, Jae-Hung

2018-04-01

The objective of this paper is to study the feasibility of panel flutter emulation using a few concentrated forces. The concentrated forces are considered to be equivalent to aerodynamic forces. The equivalence is carried out using surface spline method and principle of virtual work. The structural modeling of the plate is based on the classical plate theory and the aerodynamic modeling is based on the piston theory. The present approach differs from the linear panel flutter analysis in scheming the modal aerodynamics forces with unchanged structural properties. The solutions for the flutter problem are obtained numerically using the standard eigenvalue procedure. A few concentrated forces were considered with an optimization effort to decide their optimal locations. The optimization process is based on minimizing the error between the flutter bounds from emulated and linear flutter analysis method. The emulated flutter results for the square plate of four different boundary conditions using six concentrated forces are obtained with minimal error to the reference value. The results demonstrated the workability and viability of using concentrated forces in emulating real panel flutter. In addition, the paper includes the parametric studies of linear panel flutter whose proper literatures are not available.

Objective and Subjective Evaluation of Reflecting and Diffusing Surfaces in Auditoria

NASA Astrophysics Data System (ADS)

Cox, Trevor John

Available from UMI in association with The British Library. Requires signed TDF. The performance of reflectors and diffusers used in auditoria have been evaluated both objectively and subjectively. Two accurate systems have been developed to measure the scattering from surfaces via the cross correlation function. These have been used to measure the scattering from plane panels, curved panels and quadratic residue diffusers (QRDs). The scattering measurements have been used to test theoretical prediction methods based on the Helmholtz-Kirchhoff integral equation. Accurate prediction methods were found for all surfaces tested. The limitations of the more approximate methods have been defined. The assumptions behind Schroeder's design of the QRD have been tested and the local reacting admittance assumption found to be valid over a wide frequency range. It was found that the QRD only produces uniform scattering at low frequencies. For an on-axis source the scattering from a curved panel was as good as from a QRD. For an oblique source the QRD produced much more uniform scattering than the curved panel. The subjective measurements evaluated the smallest perceivable change in the early sound field, the part most influenced by reflectors and diffusers. A natural sounding simulation of a concert hall field within an anechoic chamber was used. Standard objective parameters were reasonable values when compared to values found in real halls and subjective preference measurements. A difference limen was measured for early lateral energy fraction (.048 +/-.005); inter aural cross correlation (.075 +/-.008); clarity index (.67 +/-.13 dB); and centre time (8.6 +/- 1.6 ms). It was found that: (i) when changes are made to diffusers and reflectors, changes in spatial impression will usually be larger than those in clarity; and (ii) acousticians can gain most by paying attention to lateral sound in auditoria. It was also found that: (i) diffuse reflections in the early sound field are not perceived differently from specular reflections; and (ii) the initial time delay gap is not significant to listener preference.

An unsteady lifting surface method for single rotation propellers

NASA Technical Reports Server (NTRS)

Williams, Marc H.

1990-01-01

The mathematical formulation of a lifting surface method for evaluating the steady and unsteady loads induced on single rotation propellers by blade vibration and inflow distortion is described. The scheme is based on 3-D linearized compressible aerodynamics and presumes that all disturbances are simple harmonic in time. This approximation leads to a direct linear integral relation between the normal velocity on the blade (which is determined from the blade geometry and motion) and the distribution of pressure difference across the blade. This linear relation is discretized by breaking the blade up into subareas (panels) on which the pressure difference is treated as approximately constant, and constraining the normal velocity at one (control) point on each panel. The piece-wise constant loads can then be determined by Gaussian elimination. The resulting blade loads can be used in performance, stability and forced response predictions for the rotor. Mathematical and numerical aspects of the method are examined. A selection of results obtained from the method is presented. The appendices include various details of the derivation that were felt to be secondary to the main development in Section 1.

A Numerical Study on the Effect of Facesheet-Core Disbonds on the Buckling Load of Curved Honeycomb Sandwich Panels

NASA Technical Reports Server (NTRS)

Pineda, Evan J.; Myers, David E.; Bednarcyk, Brett A.; Krivanek, Thomas M.

2015-01-01

A numerical study on the effect of facesheet-core disbonds on the post-buckling response of curved honeycomb sandwich panels is presented herein. This work was conducted as part of the development of a damage tolerance approach for the next-generation Space Launch System heavy lift vehicle payload fairing. As such, the study utilized full-scale fairing barrel segments as the structure of interest. The panels were composed of carbon fiber reinforced polymer facesheets and aluminum honeycomb core. The panels were analyzed numerically using the finite element method. Facesheet and core nodes in a predetermined circular region were detached to simulate a disbond induced via low-speed impact between the outer mold line facesheet and honeycomb core. Surface-to-surface contact in the disbonded region was invoked to prevent interpenetration of the facesheet and core elements. The diameter of this disbonded region was varied and the effect of the size of the disbond on the post-buckling response was observed. A significant change in the slope of the edge load-deflection response was used to determine the onset of global buckling and corresponding buckling load.

An imaging-based photometric and colorimetric measurement method for characterizing OLED panels for lighting applications

NASA Astrophysics Data System (ADS)

Zhu, Yiting; Narendran, Nadarajah; Tan, Jianchuan; Mou, Xi

2014-09-01

The organic light-emitting diode (OLED) has demonstrated its novelty in displays and certain lighting applications. Similar to white light-emitting diode (LED) technology, it also holds the promise of saving energy. Even though the luminous efficacy values of OLED products have been steadily growing, their longevity is still not well understood. Furthermore, currently there is no industry standard for photometric and colorimetric testing, short and long term, of OLEDs. Each OLED manufacturer tests its OLED panels under different electrical and thermal conditions using different measurement methods. In this study, an imaging-based photometric and colorimetric measurement method for OLED panels was investigated. Unlike an LED that can be considered as a point source, the OLED is a large form area source. Therefore, for an area source to satisfy lighting application needs, it is important that it maintains uniform light level and color properties across the emitting surface of the panel over a long period. This study intended to develop a measurement procedure that can be used to test long-term photometric and colorimetric properties of OLED panels. The objective was to better understand how test parameters such as drive current or luminance and temperature affect the degradation rate. In addition, this study investigated whether data interpolation could allow for determination of degradation and lifetime, L70, at application conditions based on the degradation rates measured at different operating conditions.

76 FR 13567 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Adoption of Control...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-14

... Flat Wood Paneling Surface Coating Processes AGENCY: Environmental Protection Agency (EPA). ACTION... sources covered by EPA's Control Techniques Guidelines (CTG) standards for flat wood paneling surface... Protection (PADEP) submitted to EPA a SIP revision concerning the adoption of the CTG for flat wood paneling...

Thin film concentrator panel development

NASA Technical Reports Server (NTRS)

Zimmerman, D. K.

1982-01-01

The development and testing of a rigid panel concept that utilizes a thin film reflective surface for application to a low-cost point-focusing solar concentrator is discussed. It is shown that a thin film reflective surface is acceptable for use on solar concentrators, including 1500 F applications. Additionally, it is shown that a formed steel sheet substrate is a good choice for concentrator panels. The panel has good optical properties, acceptable forming tolerances, environmentally resistant substrate and stiffeners, and adaptability to low to mass production rates. Computer simulations of the concentrator optics were run using the selected reflector panel design. Experimentally determined values for reflector surface specularity and reflectivity along with dimensional data were used in the analysis. The simulations provided intercept factor and net energy into the aperture as a function of aperture size for different surface errors and pointing errors. Point source and Sun source optical tests were also performed.

Study of the tactile perception of bathroom tissues: Comparison between the sensory evaluation by a handfeel panel and a tribo-acoustic artificial finger.

PubMed

Thieulin, C; Pailler-Mattei, C; Vargiolu, R; Lancelot, S; Zahouani, H

2017-02-01

Tactile perception is one of the sensorial modes most stimulated by our daily environment. In particular, perceived softness is an important parameter for judging the sensory quality of surfaces and fabrics. Unfortunately, its assessment greatly depends on the tactile sense of each person, which in turn depends on many factors. Currently, the predominant method for evaluating the tactile perception of fabrics is the human handfeel panel. This qualitative approach does not permit the quantitative measure of touch feel perception. In this study, we present a new artificial finger device to investigate the tactile sensing of ten bathroom tissues. It enables simultaneously measuring the friction and vibrations caused when sliding an artificial finger on the surface of the tissue. The comparison between the results obtained with the artificial finger and the tactile perception evaluated using a handfeel panel showed that the artificial finger is able to separate the two parts of the tactile perception of bathroom tissues: softness and surface texture (velvetiness). The statistical analysis suggests that there is a good correlation between the vibrations measured with the artificial finger and the softness evaluated by the panel. It then shows that the friction measured by the artificial finger is related to the surface texture of a bathroom tissue. The ability of the artificial finger to mimic human touch is demonstrated. Finally, a Principal Component Analysis orders the signatures of the tactile perception of the bathroom tissues in four different groups. Copyright © 2016. Published by Elsevier B.V.

PMARC - PANEL METHOD AMES RESEARCH CENTER

NASA Technical Reports Server (NTRS)

Ashby, D. L.

1994-01-01

Panel methods are moderate cost tools for solving a wide range of engineering problems. PMARC (Panel Method Ames Research Center) is a potential flow panel code that numerically predicts flow fields around complex three-dimensional geometries. PMARC's predecessor was a panel code named VSAERO which was developed for NASA by Analytical Methods, Inc. PMARC is a new program with many additional subroutines and a well-documented code suitable for powered-lift aerodynamic predictions. The program's open architecture facilitates modifications or additions of new features. Another improvement is the adjustable size code which allows for an optimum match between the computer hardware available to the user and the size of the problem being solved. PMARC can be resized (the maximum number of panels can be changed) in a matter of minutes. Several other state-of-the-art PMARC features include internal flow modeling for ducts and wind tunnel test sections, simple jet plume modeling essential for the analysis and design of powered-lift aircraft, and a time-stepping wake model which allows the study of both steady and unsteady motions. PMARC is a low-order panel method, which means the singularities are distributed with constant strength over each panel. In many cases low-order methods can provide nearly the same accuracy as higher order methods (where the singularities are allowed to vary linearly or quadratically over each panel). Low-order methods have the advantage of a shorter computation time and do not require exact matching between panels. The flow problem is solved by assuming that the body is at rest in a moving flow field. The body is modeled as a closed surface which divides space into two regions -- one region contains the flow field of interest and the other contains a fictitious flow. External flow problems, such as a wing in a uniform stream, have the external region as the flow field of interest and the internal flow as the fictitious flow. This arrangement is reversed for internal flow problems where the internal region contains the flow field of interest and the external flow field is fictitious. In either case it is assumed that the velocity potentials in both regions satisfy Laplace's equation. PMARC has extensive geometry modeling capabilities for handling complex, three-dimensional surfaces. As with all panel methods, the geometry must be modeled by a set of panels. For convenience, the geometry is usually subdivided into several pieces and modeled with sets of panels called patches. A patch may be folded over on itself so that opposing sides of the patch form a common line. For example, wings are normally modeled with a folded patch to form the trailing edge of the wing. PMARC also has the capability to automatically generate a closing tip patch. In the case of a wing, a tip patch could be generated to close off the wing's third side. PMARC has a simple jet model for simulating a jet plume in a crossflow. The jet plume shape, trajectory, and entrainment velocities are computed using the Adler/Baron jet in crossflow code. This information is then passed back to PMARC. The wake model in PMARC is a time-stepping wake model. The wake is convected downstream from the wake separation line by the local velocity flowfield. With each time step, a new row of wake panels is added to the wake at the wake separation line. PMARC also allows an initial wake to be specified if desired, or, as a third option, no wakes need be modeled. The effective presentation of results for aerodynamics problems requires the generation of report-quality graphics. PMAPP (ARC-12751), the Panel Method Aerodynamic Plotting Program, (Sterling Software), was written for scientists at NASA's Ames Research Center to plot the aerodynamic analysis results (flow data) from PMARC. PMAPP is an interactive, color-capable graphics program for the DEC VAX or MicroVAX running VMS. It was designed to work with a variety of terminal types and hardcopy devices. PMAPP is available separately from COSMIC. PMARC was written in standard FORTRAN77 using adjustable size arrays throughout the code. Redimensioning PMARC will change the amount of disk space and memory the code requires to be able to run; however, due to its memory requirements, this program does not readily lend itself to implementation on MS-DOS based machines. The program was implemented on an Apple Macintosh (using 2.5 MB of memory) and tested on a VAX/VMS computer. The program is available on a 3.5 inch Macintosh format diskette (standard media) or in VAX BACKUP format on TK50 tape cartridge or 9-track magnetic tape. PMARC was developed in 1989.

PROGRAM VSAERO: A computer program for calculating the non-linear aerodynamic characteristics of arbitrary configurations: User's manual

NASA Technical Reports Server (NTRS)

Maskew, B.

1982-01-01

VSAERO is a computer program used to predict the nonlinear aerodynamic characteristics of arbitrary three-dimensional configurations in subsonic flow. Nonlinear effects of vortex separation and vortex surface interaction are treated in an iterative wake-shape calculation procedure, while the effects of viscosity are treated in an iterative loop coupling potential-flow and integral boundary-layer calculations. The program employs a surface singularity panel method using quadrilateral panels on which doublet and source singularities are distributed in a piecewise constant form. This user's manual provides a brief overview of the mathematical model, instructions for configuration modeling and a description of the input and output data. A listing of a sample case is included.

Damage detection in sandwich composite materials using laser vibrometry in conjunction with nonlinear system identification

NASA Astrophysics Data System (ADS)

Underwood, Sara; Koester, David; Adams, Douglas E.

2009-03-01

Fiberglass sandwich panels are tested to study a vibration-based method for locating damage in composite materials. This method does not rely on a direct comparison of the natural frequencies, mode shapes, or residues in the forced vibration response data. Specifically, a nonlinear system identification based method for damage detection is sought that reduces the sensitivity of damage detection results to changes in vibration measurements due to variations in boundary conditions, environmental conditions, and material properties of the panel. Damage mechanisms considered include a disbond between the core and face sheet and a crack within the core. A panel is excited by a skewed piezoelectric actuator over a broad frequency range while a three-dimensional scanning laser vibrometer measures the surface velocity of the panel along three orthogonal axes. The forced frequency response data measured using the scanning laser vibrometer at multiple excitation amplitudes is processed to identify areas of the panel that exhibit significant nonlinear response characteristics. It is demonstrated that these localized nonlinearities in the panel coincide with the damaged areas of the composite material. Because changes in the measured frequency response functions due to nonlinear distortions associated with the damage can be identified without comparing the vibration data to a reference (baseline) signature of the undamaged material, this vibration technique for damage detection in composite materials exhibits less sensitivity to variations in the underlying linear characteristics than traditional methods. It is also demonstrated that the damage at a given location can be classified as either due to a disbond or core crack because these two types of damage produce difference signatures when comparing the multi-amplitude frequency response functions.

Experimental investigations on active cooling thermal protection structure of hydrocarbon-fueled scramjet combustor in arc heated facility

NASA Astrophysics Data System (ADS)

Jianqiang, Tu; Jinlong, Peng; Xianning, Yang; Lianzhong, Chen

2016-10-01

The active cooling thermal protection technology is the efficient method to resolve the long-duration work and reusable problems of hydrocarbon-fueled scramjet combustor, where worst thermo-mechanical loads occur. The fuel is passed through coolant channels adjacent to the heated surfaces to absorb heat from the heating exchanger panels, prior to injection into the combustor. The heating exchanger both cooled down the wall temperature of the combustor wall and heats and cracks the hydrocarbon fuel inside the panel to permit an easier combustion and satisfying combustion efficiency. The subscale active cooling metallic panels, with dimensions of 100×100 mm and different coolant channel sizes, have been tested under typical combustion thermal environment produced by arc heated Turbulent Flow Duct (TFD). The heat exchange ability of different coolant channel sizes has been obtained. The big-scale active cooling metallic panel, with dimensions of 100 × 750 mm and the coolant channel sizes of better heating exchange performance, has been made and tested in the big-scale arc heated TFD facility. The test results show that the local superheated ablation is easy to happen for the cooling fuel assigned asymmetrically in the bigscale active cooling metallic panel, and the cooling fuel rate can reduce 8%˜10% after spraying the Thermal Barrier Coating (TBC) in the heating surface.

Beeswax as phase change material to improve solar panel’s performance

NASA Astrophysics Data System (ADS)

Thaib, R.; Rizal, S.; Riza, M.; Mahlia, T. M. I.; Rizal, T. A.

2018-02-01

One of the main obstacles faced during the operation of photovoltaic (PV) panels was overheating due to excessive solar radiation and high ambient temperatures. In this research, investigates the use of beeswax phase change materials (PCM) to maintain the temperature of the panels close to ambient. Solar panels used in this study has 839 mm length, 537 mm wide, and 50 mm thick, with maximum output power at 50 W. During the study, there were two solar panels was evaluated, one without phase change material while the other one was using beeswax phase change material. Solar panels were mounted at 15° slope. Variables observed was the temperature of solar panel’s surface, output voltage and current that produced by PV panels, wind speed around solar panels, and solar radiation. The observation was started at 07:00 am and ended at 06:00 pm. The research shows that maximum temperature of solar panels surface without phase change material is ranging between 46-49 °C, and electrical efficiency is about 7.2-8.8%. Meanwhile, for solar panels with beeswax phase change material, the maximum temperature solar panels surface is relatively low ranging between 33-34 °C, and its electrical efficiency seems to increase about 9.1-9.3%.

Ultrasonic assessment of additive manufactured Ti-6Al-4V

NASA Astrophysics Data System (ADS)

Schehl, Norman; Kramb, Vicki; Dierken, Josiah; Aldrin, John; Schwalbach, Edwin; John, Reji

2018-04-01

Additive Manufacturing (AM) processes offer the potential for manufacturing cost savings and rapid insertion into service through production of near net shape components for complicated structures. Use of these parts in high reliability applications such as those in the aerospace industry will require nondestructive characterization methods to ensure post-process material quality in as-built condition. Ultrasonic methods can be used for this quality verification. Depending on the application, the service life of AM components can be sensitive to the part surface condition. The surface roughness and layered structure inherent to the electron-beam powder-bed fusion process necessitates new approaches to evaluate subsurface material integrity in its presence. Experimental methods and data analytics may improve the evaluation of as-built additively manufactured materials. This paper discusses the assessment of additively manufactured EBM Ti-6Al-4V panels using ultrasonic methods and the data analytics applied to evaluate material integrity. The assessment was done as an exploratory study as the discontinuities of interest in these test samples were not known when the measurements were performed. Water immersion ultrasonic techniques, including pulse-echo and through transmission with 10 MHz focused transducers, were used to explore the material integrity of as-built plates. Subsequent destructive mechanical tests of specimens extracted from the plates provided fracture locations indicating critical flaws. To further understand the effect of surface-roughness, an evaluation of ultrasonic response in the presence of as-built surfaces and with the surface removed was performed. The assessment of additive manufactured EBM Ti-6Al-4V panels with ultrasonic techniques indicated that ultrasonic energy was attenuated by the as-built surface roughness. In addition, feature detection was shown to be sensitive to experimental ultrasonic parameters and flaw morphology.

Pulsed thermography detection of water and hydraulic oil intrusion in the honeycomb sandwich structure composite

NASA Astrophysics Data System (ADS)

Zhao, Shi-bin; Zhang, Cun-lin; Wu, Nai-ming

2011-08-01

Water and hydraulic oil intrusion inside honeycomb sandwich Structure Composite during service has been linked to in-flight failure in some aircraft. There is an ongoing effort to develop nondestructive testing methods to detect the presence of water and hydraulic oil within the sandwich panels. Pulsed thermography(PT) represents an attractive approach in that it is sensitive to the change of thermal properties. Using a flash lamp PT, testing can be applied directly to the surface of the panel. The viability of PT is demonstrated through laboratory imaging of both water and hydraulic oil within sandwich panels. The detection of water and hydraulic oil intrusion using a one-sided flash lamp PT is presented. It is shown that simple detection, as well as spatial localization of water and hydraulic oil within sandwich panels, and assign the quantity of water and hydraulic oil is possible.

Development and testing of Parabolic Dish Concentrator No. 1

NASA Technical Reports Server (NTRS)

Dennison, E. W.; Thostesen, T. O.

1984-01-01

Parabolic Dish Concentrator No. 1 (PDC-1) is a 12-m-diameter prototype concentrator with low life-cycle costs for use with thermal-to-electric energy conversion devices. The concentrator assembly features panels made of a resin transfer molded balsa core/fiberglass sandwich with plastic reflective film as the reflective surface and a ribbed framework to hold the panels in place. The concentrator assembly tracks in azimuth and elevation on a base frame riding on a circular track. It is shown that the panels do not exhibit the proper parabolic contour. However, thermal gradients were discovered in the panels with daily temperature changes. The PDC-1 has sufficient optical quality to operate satisfactorily in a dish-electric system. The PDC-1 development provides the impetus for creating innovative optical testing methods and valuable information for use in designing and fabricating concentrators of future dish-electric systems.

Optical panel system including stackable waveguides

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeSanto, Leonard; Veligdan, James T.

An optical panel system including stackable waveguides is provided. The optical panel system displays a projected light image and comprises a plurality of planar optical waveguides in a stacked state. The optical panel system further comprises a support system that aligns and supports the waveguides in the stacked state. In one embodiment, the support system comprises at least one rod, wherein each waveguide contains at least one hole, and wherein each rod is positioned through a corresponding hole in each waveguide. In another embodiment, the support system comprises at least two opposing edge structures having the waveguides positioned therebetween, whereinmore » each opposing edge structure contains a mating surface, wherein opposite edges of each waveguide contain mating surfaces which are complementary to the mating surfaces of the opposing edge structures, and wherein each mating surface of the opposing edge structures engages a corresponding complementary mating surface of the opposite edges of each waveguide.« less

Optical panel system including stackable waveguides

DOEpatents

DeSanto, Leonard; Veligdan, James T.

2007-03-06

An optical panel system including stackable waveguides is provided. The optical panel system displays a projected light image and comprises a plurality of planar optical waveguides in a stacked state. The optical panel system further comprises a support system that aligns and supports the waveguides in the stacked state. In one embodiment, the support system comprises at least one rod, wherein each waveguide contains at least one hole, and wherein each rod is positioned through a corresponding hole in each waveguide. In another embodiment, the support system comprises at least two opposing edge structures having the waveguides positioned therebetween, wherein each opposing edge structure contains a mating surface, wherein opposite edges of each waveguide contain mating surfaces which are complementary to the mating surfaces of the opposing edge structures, and wherein each mating surface of the opposing edge structures engages a corresponding complementary mating surface of the opposite edges of each waveguide.

Prediction of submarine scattered noise by the acoustic analogy

NASA Astrophysics Data System (ADS)

Testa, C.; Greco, L.

2018-07-01

The prediction of the noise scattered by a submarine subject to the propeller tonal noise is here addressed through a non-standard frequency-domain formulation that extends the use of the acoustic analogy to scattering problems. A boundary element method yields the scattered pressure upon the hull surface by the solution of a boundary integral equation, whereas the noise radiated in the fluid domain is evaluated by the corresponding boundary integral representation. Propeller-induced incident pressure field on the scatterer is detected by combining an unsteady three-dimensional panel method with the Bernoulli equation. For each frequency of interest, numerical results concern with sound pressure levels upon the hull and in the flowfield. The validity of the results is established by a comparison with a time-marching hydrodynamic panel method that solves propeller and hull jointly. Within the framework of potential-flow hydrodynamics, it is found out that the scattering formulation herein proposed is appropriate to successfully capture noise magnitude and directivity both on the hull surface and in the flowfield, yielding a computationally efficient solution procedure that may be useful in preliminary design/multidisciplinary optimization applications.

Initial development of high-accuracy CFRP panel for DATE5 antenna

NASA Astrophysics Data System (ADS)

Qian, Yuan; Lou, Zheng; Hao, Xufeng; Zhu, Jing; Cheng, Jingquan; Wang, Hairen; Zuo, Yingxi; Yang, Ji

2016-07-01

DATE5 antenna, which is a 5m telescope for terahertz exploration, will be sited at Dome A, Antarctica. It is necessary to keep high surface accuracy of the primary reflector panels so that high observing efficiency can be achieved. In antenna field, carbon fiber reinforced composite (CFRP) sandwich panels are widely used as these panels are light in weight, high in strength, low in thermal expansion, and cheap in mass fabrication. In DATE5 project, CFRP panels are important panel candidates. In the design study phase, a CFRP prototype panel of 1-meter size is initially developed for the verification purpose. This paper introduces the material arrangement in the sandwich panel, measured performance of this testing sandwich structure samples, and together with the panel forming process. For anti-icing in the South Pole region, a special CFRP heating film is embedded in the front skin of sandwich panel. The properties of some types of basic building materials are tested. Base on the results, the deformation of prototype panel with different sandwich structures and skin layers are simulated and a best structural concept is selected. The panel mold used is a high accuracy one with a surface rms error of 1.4 μm. Prototype panels are replicated from the mold. Room temperature curing resin is used to reduce the thermal deformation in the resin transfer process. In the curing, vacuum negative pressure technology is also used to increase the volume content of carbon fiber. After the measurement of the three coordinate measure machine (CMM), a prototype CFRP panel of 5.1 μm rms surface error is developed initially.

Full-Scale Evaluation of DuraDeck (registered trademark) and MegaDeck (trademark) Matting Systems

DTIC Science & Technology

2013-07-01

plates studded with threaded bolts were placed ERDC/GSL TR-13-27 10 underneath two pre-drilled corners of the panel. The plates were positioned so...metal plates studded with threaded ERDC/GSL TR-13-27 4 Figure 1. DuraDeck® mat panel, top surface. Figure 2. DuraDeck® mat panel, bottom surface...ERDC/GSL TR-13-27 5 bolts , as shown in Figure 3, underneath the mat corners and then installing special connector nuts from the top surface

Flow analysis for the nacelle of an advanced ducted propeller at high angle-of-attack and at cruise with boundary layer control

NASA Technical Reports Server (NTRS)

Hwang, D. P.; Boldman, D. R.; Hughes, C. E.

1994-01-01

An axisymmetric panel code and a three dimensional Navier-Stokes code (used as an inviscid Euler code) were verified for low speed, high angle of attack flow conditions. A three dimensional Navier-Stokes code (used as an inviscid code), and an axisymmetric Navier-Stokes code (used as both viscous and inviscid code) were also assessed for high Mach number cruise conditions. The boundary layer calculations were made by using the results from the panel code or Euler calculation. The panel method can predict the internal surface pressure distributions very well if no shock exists. However, only Euler and Navier-Stokes calculations can provide a good prediction of the surface static pressure distribution including the pressure rise across the shock. Because of the high CPU time required for a three dimensional Navier-Stokes calculation, only the axisymmetric Navier-Stokes calculation was considered at cruise conditions. The use of suction and tangential blowing boundary layer control to eliminate the flow separation on the internal surface was demonstrated for low free stream Mach number and high angle of attack cases. The calculation also shows that transition from laminar flow to turbulent flow on the external cowl surface can be delayed by using suction boundary layer control at cruise flow conditions. The results were compared with experimental data where possible.

Combinatorial materials research applied to the development of new surface coatings VII: An automated system for adhesion testing

NASA Astrophysics Data System (ADS)

Chisholm, Bret J.; Webster, Dean C.; Bennett, James C.; Berry, Missy; Christianson, David; Kim, Jongsoo; Mayo, Bret; Gubbins, Nathan

2007-07-01

An automated, high-throughput adhesion workflow that enables pseudobarnacle adhesion and coating/substrate adhesion to be measured on coating patches arranged in an array format on 4×8in.2 panels was developed. The adhesion workflow consists of the following process steps: (1) application of an adhesive to the coating array; (2) insertion of panels into a clamping device; (3) insertion of aluminum studs into the clamping device and onto coating surfaces, aligned with the adhesive; (4) curing of the adhesive; and (5) automated removal of the aluminum studs. Validation experiments comparing data generated using the automated, high-throughput workflow to data obtained using conventional, manual methods showed that the automated system allows for accurate ranking of relative coating adhesion performance.

Experimental Design for the Evaluation of Detection Techniques of Hidden Corrosion Beneath the Thermal Protective System of the Space Shuttle Orbiter

NASA Technical Reports Server (NTRS)

Kemmerer, Catherine C.; Jacoby, Joseph A.; Lomness, Janice K.; Hintze, Paul E.; Russell, Richard W.

2007-01-01

The detection of corrosion beneath Space Shuttle Orbiter thermal protective system is traditionally accomplished by removing the Reusable Surface Insulation tiles and performing a visual inspection of the aluminum substrate and corrosion protection system. This process is time consuming and has the potential to damage high cost tiles. To evaluate non-intrusive NDE methods, a Proof of Concept (PoC) experiment was designed and test panels were manufactured. The objective of the test plan was three-fold: establish the ability to detect corrosion hidden from view by tiles; determine the key factor affecting detectability; roughly quantify the detection threshold. The plan consisted of artificially inducing dimensionally controlled corrosion spots in two panels and rebonding tile over the spots to model the thermal protective system of the orbiter. The corrosion spot diameter ranged from 0.100" to 0.600" inches and the depth ranged from 0.003" to 0.020". One panel consisted of a complete factorial array of corrosion spots with and without tile coverage. The second panel consisted of randomized factorial points replicated and hidden by tile. Conventional methods such as ultrasonics, infrared, eddy current and microwave methods have shortcomings. Ultrasonics and IR cannot sufficiently penetrate the tiles, while eddy current and microwaves have inadequate resolution. As such, the panels were interrogated using Backscatter Radiography and Terahertz Imaging. The terahertz system successfully detected artificially induced corrosion spots under orbiter tile and functional testing is in-work in preparation for implementation.

Rivited panel surface measurement using photogrammetry

NASA Technical Reports Server (NTRS)

Merrick, W. D.; Lobb, V. B.; Lansing, F. L.; Stoller, F. W.

1986-01-01

Two riveted antenna panels on rings number 3 and 9 were removed from the 34m antenna at DSS-15, fixed in the leveled position and the surface was photographed indoors. The results from this pilot photogrammetric demonstration and diagnostics of panel surface contours, are presented. The photogrammetric network for each panel incorporated eight photographs, two from each of four camera stations and observed over 200 targets. The accuracy (1 sigma) of the XYZ coordinates for the error ellipsoids was + or - 0.013 mm (0.0005 inch). This level of precision relative to the object size corresponds roughly to 1 part in 250,000 which is superior to conventional dial sweep-arm template techniques by at least a factor of 4.

Self-diagnosis of damage in fibrous composites using electrical resistance measurements

NASA Astrophysics Data System (ADS)

Kang, Ji Ho; Paty, Spandana; Kim, Ran Y.; Tandon, G. P.

2006-03-01

The objective of this research was to develop a practical integrated approach using extracted features from electrical resistance measurements and coupled electromechanical models of damage, for in situ damage detection and sensing in carbon fiber reinforced plastic (CFRP) composite structures. To achieve this objective, we introduced specific known damage (in terms of type, size, and location) into CFRP laminates and established quantitative relationships with the electrical resistance measurements. For processing of numerous measurement data, an autonomous data acquisition system was devised. We also established a specimen preparation procedure and a method for electrode setup. Coupon and panel CFRP laminate specimens with several known damage were tested and post-processed with the measurement data. Coupon specimens with various sizes of artificial delaminations obtained by inserting Teflon film were manufactured and the resistance was measured. The measurement results showed that increase of delamination size led to increase of resistance implying that it is possible to sense the existence and size of delamination. Encouraged by the results of coupon specimens, we implemented the measurement system on panel specimens. Three different quasi-isotropic panels were designed and manufactured: a panel with artificial delamination by inserting Teflon film at the midplane, a panel with artificial delamination by inserting Teflon film between the second and third plies from the surface, and an undamaged panel. The first two panels were designed to determine the feasibility of detecting delamination using the developed measurement system. The third panel had no damage at first, and then three different sizes of holes were drilled at a chosen location. Panels were prepared using the established procedures with six electrode connections on each side making a total of twenty-four electrode connections for a panel. All possible pairs of electrodes were scanned and the resistance was measured for each pair. The measurement results showed the possibility of the established measurement system for an in-situ damage detection method for CFRP composite structures.

Post-Buckling Analysis of Curved Honeycomb Sandwich Panels Containing Interfacial Disbonds

NASA Technical Reports Server (NTRS)

Pineda, Evan J.; Bednarcyk, Brett A.; Krivanek, Thomas K.

2016-01-01

A numerical study on the effect of facesheet-core disbonds on the post-buckling response of curved honeycomb sandwich panels is presented herein. This work was conducted as part of the development of a damage tolerance plan for the next-generation Space Launch System heavy lift launch vehicle payload fairing. As such, the study utilized full-scale fairing barrel segments as the structure of interest. The panels were composed of carbon fiber reinforced polymer facesheets and aluminum honeycomb core. The panels were analyzed numerically using the finite element method incorporating geometric nonlinearity. In a predetermined circular region, facesheet and core nodes were detached to simulate a disbond, between the outer mold line facesheet and honeycomb core, induced via low-speed impact. Surface-to-surface contact in the disbonded region was invoked to prevent interpenetration of the facesheet and core elements and obtain realistic stresses in the core. The diameter of this disbonded region was varied and the effect of the size of the disbond on the post-buckling response was observed. Significant changes in the slope of the edge load-deflection response were used to determine the onset of global buckling and corresponding buckling load. Finally, several studies were conducted to determine the sensitivity of the numerical predictions to refinement in the finite element mesh.

Report of the panel on the land surface: Process of change, section 5

NASA Technical Reports Server (NTRS)

Adams, John B.; Barron, Eric E.; Bloom, Arthur A.; Breed, Carol; Dohrenwend, J.; Evans, Diane L.; Farr, Thomas T.; Gillespie, Allan R.; Isaks, B. L.; Williams, Richard S.

1991-01-01

The panel defined three main areas of study that are central to the Solid Earth Science (SES) program: climate interactions with the Earth's surface, tectonism as it affects the Earth's surface and climate, and human activities that modify the Earth's surface. Four foci of research are envisioned: process studies with an emphasis on modern processes in transitional areas; integrated studies with an emphasis on long term continental climate change; climate-tectonic interactions; and studies of human activities that modify the Earth's surface, with an emphasis on soil degradation. The panel concluded that there is a clear requirement for global coverage by high resolution stereoscopic images and a pressing need for global topographic data in support of studies of the land surface.

Coating and curing apparatus and methods

DOEpatents

Brophy, Brenor L; Maghsoodi, Sina; Neyman, Patrick J; Gonsalves, Peter R; Hirsch, Jeffrey G; Yang, Yu S

2015-02-24

Disclosed are coating apparatus including flow coating and roll-coating that may be used for uniform sol-gel coating of substrates such as glass, solar panels, windows or part of an electronic display. Also disclosed are methods for substrate preparation, flow coating and roll coating. Lastly systems and methods for skin curing sol-gel coatings deposited onto the surface of glass substrates using a high temperature air-knife are disclosed.

The distribution of deformation in parallel fault-related folds with migrating axial surfaces: comparison between fault-propagation and fault-bend folding

NASA Astrophysics Data System (ADS)

Salvini, Francesco; Storti, Fabrizio

2001-01-01

In fault-related folds that form by axial surface migration, rocks undergo deformation as they pass through axial surfaces. The distribution and intensity of deformation in these structures has been impacted by the history of axial surface migration. Upon fold initiation, unique dip panels develop, each with a characteristic deformation intensity, depending on their history. During fold growth, rocks that pass through axial surfaces are transported between dip panels and accumulate additional deformation. By tracking the pattern of axial surface migration in model folds, we predict the distribution of relative deformation intensity in simple-step, parallel fault-bend and fault-propagation anticlines. In both cases the deformation is partitioned into unique domains we call deformation panels. For a given rheology of the folded multilayer, deformation intensity will be homogeneously distributed in each deformation panel. Fold limbs are always deformed. The flat crests of fault-propagation anticlines are always undeformed. Two asymmetric deformation panels develop in fault-propagation folds above ramp angles exceeding 29°. For lower ramp angles, an additional, more intensely-deformed panel develops at the transition between the crest and the forelimb. Deformation in the flat crests of fault-bend anticlines occurs when fault displacement exceeds the length of the footwall ramp, but is never found immediately hinterland of the crest to forelimb transition. In environments dominated by brittle deformation, our models may serve as a first-order approximation of the distribution of fractures in fault-related folds.

Beam-tracing model for predicting sound fields in rooms with multilayer bounding surfaces

NASA Astrophysics Data System (ADS)

Wareing, Andrew; Hodgson, Murray

2005-10-01

This paper presents the development of a wave-based room-prediction model for predicting steady-state sound fields in empty rooms with specularly reflecting, multilayer surfaces. A triangular beam-tracing model with phase, and a transfer-matrix approach to model the surfaces, were involved. Room surfaces were modeled as multilayers of fluid, solid, or porous materials. Biot theory was used in the transfer-matrix formulation of the porous layer. The new model consisted of the transfer-matrix model integrated into the beam-tracing algorithm. The transfer-matrix model was validated by comparing predictions with those by theory, and with experiment. The test surfaces were a glass plate, double drywall panels, double steel panels, a carpeted floor, and a suspended-acoustical ceiling. The beam-tracing model was validated in the cases of three idealized room configurations-a small office, a corridor, and a small industrial workroom-with simple boundary conditions. The number of beams, the reflection order, and the frequency resolution required to obtain accurate results were investigated. Beam-tracing predictions were compared with those by a method-of-images model with phase. The model will be used to study sound fields in rooms with local- or extended-reaction multilayer surfaces.

Surface Resistance of Jute Fibre/Polylactic Acid Biocomposite to Wet Heat

NASA Astrophysics Data System (ADS)

Zandvliet, Clio; Bandyopadhyay, N. R.; Ray, Dipa

2016-04-01

Jute fibre/polylactic acid (PLA) composite is of special interest because both resin and reinforcement come from renewable resources. Thus, it could be a more eco-friendly alternative to glass fibre composite [1] and to conventional wood-based panels made with phenol-formaldehyde resin which present many drawbacks for the workers and the environment [2]. Yet the water affinity of the natural fibres, the susceptibility of PLA towards hydrolysis and the low glass transition of the PLA raise a question about the surface resistance of such composites to wet heat in service condition for a furniture application [3]. In this work, the surface resistance of PLA/jute composite alone and with two different varnishes are investigated in regard to an interior application following the standard test method in accordance to BS EN 18721:2009: "Furniture: assessment of surface resistance to wet heat". It is compared to two common wood based panels, plywood and hardboard. After test, the composite material surface is found to be more affected than plywood and hardboard, but it becomes resistant to wet heat when a layer of biosourced varnish or petrol-based polyurethane varnish are applied on the surface.

Evaluation of lunar regolith geopolymer binder as a radioactive shielding material for space exploration applications

NASA Astrophysics Data System (ADS)

Montes, Carlos; Broussard, Kaylin; Gongre, Matthew; Simicevic, Neven; Mejia, Johanna; Tham, Jessica; Allouche, Erez; Davis, Gabrielle

2015-09-01

Future manned missions to the moon will require the ability to build structures using the moon's natural resources. The geopolymer binder described in this paper (Lunamer) is a construction material that consists of up to 98% lunar regolith, drastically reducing the amount of material that must be carried from Earth in the event of lunar construction. This material could be used to fabricate structural panels and interlocking blocks that have radiation shielding and thermal insulation characteristics. These panels and blocks could be used to construct living quarters and storage facilities on the lunar surface, or as shielding panels to be installed on crafts launched from the moon surface to deep-space destinations. Lunamer specimens were manufactured in the laboratory and compressive strength results of up to 16 MPa when cast with conventional methods and 37 MPa when cast using uniaxial pressing were obtained. Simulation results have shown that the mechanical and chemical properties of Lunamer allow for adequate radiation shielding for a crew inside the lunar living quarters without additional requirements.

New concept in brazing metallic honeycomb panels

NASA Technical Reports Server (NTRS)

Carter, P. D.; Layton, R. E.; Stratton, F. W.

1973-01-01

Aluminum oxide coating provides surface which will not be wetted by brazing alloy and which stops metallic diffusion welding of tooling materials to part being produced. This method eliminates loss of tooling materials and parts from braze wetting and allows fall-apart disassembly of tooling after brazing.

Hypervelocity Impact Testing of IM7/977-3 with Micro-Sized Particles

NASA Technical Reports Server (NTRS)

Smith, J. G.; Jegley, D. C.; Siochi, E. J.; Wells, B. K.

2010-01-01

Ground-based hypervelocity imapct testing was conducted on IM7/977-3 quasi-isotropic flat panels at normal incidence using micron-sized particles (i.e. less than or equal to 100 microns) of soda lime glass and olivine. Testing was performed at room temperature (RT) and 175 C with results from the 175 C test compared to those obtained at RT. Between 10 and 30 particles with velocities ranging from 5 to 13 km/s impacted each panel surface for each test temperature. Panels were ultrasonically scanned prior to and after impact testing to assess internal damage. Post-impact analysis included microscopic examination of the surface, determination of particle speed and location, and photomicroscopy for microcrack assessment. Internal damage was observed by ultrasonic inspection on panels impacted at 175 C, whereas damage for the RT impacted panels was confined to surface divets/craters as determined by microscopic analysis.

Robust superhydrophobic surface on Al substrate with durability, corrosion resistance and ice-phobicity

PubMed Central

Wang, Guoyong; Liu, Shuai; Wei, Sufeng; Liu, Yan; Lian, Jianshe; Jiang, Qing

2016-01-01

Practical application of superhydrophobic surfaces is limited by the fragility of nanoscale asperities. Combining chemical etching and anodization, microscale pits and nanoscale pores, instead of the micro and nano protrusions on traditional superhydrophobic surfaces mimicking Lutos leaves, were fabricated on commercially pure aluminum surfaces. After modified by FDTS, the surfaces were superhydrophobic and self-cleaning. The ultrahigh hardness and electrochemical stability of Al2O3 coating endowed the surface excellent mechanical durability and good corrosion resistance. Because the method is scalable, it may find practical application on body panels of automobiles and aircrafts and so on. PMID:26853810

PAN AIR: A Computer Program for Predicting Subsonic or Supersonic Linear Potential Flows About Arbitrary Configurations Using a Higher Order Panel Method. Volume 1; Theory Document (Version 1.1)

NASA Technical Reports Server (NTRS)

Magnus, Alfred E.; Epton, Michael A.

1981-01-01

An outline of the derivation of the differential equation governing linear subsonic and supersonic potential flow is given. The use of Green's Theorem to obtain an integral equation over the boundary surface is discussed. The engineering techniques incorporated in the PAN AIR (Panel Aerodynamics) program (a discretization method which solves the integral equation for arbitrary first order boundary conditions) are then discussed in detail. Items discussed include the construction of the compressibility transformations, splining techniques, imposition of the boundary conditions, influence coefficient computation (including the concept of the finite part of an integral), computation of pressure coefficients, and computation of forces and moments.

Development of technology for the fabrication of reliable laminar flow control panels on subsonic transports

NASA Technical Reports Server (NTRS)

1976-01-01

The feasibility of using porous composite materials (Kevlar, Doweave, and Leno Weave) as lightweight, efficient laminar flow control (LFC) surface materials is compared to the metallic 319L stainless Dynapore surfaces and electron beam drilled composite surfaces. Areas investigated include: (1) selection of the LFC-suitable surface materials, structural materials, and fabrication techniques for the LFC aircraft skins; (2) aerodynamic static air flow test results in terms of pressure drop through the LFC panel and the corresponding effective porosity; (3) structural design definition and analyses of the panels, and (4) contamination effects on static drop and effective porosity. Conclusions are presented and discussed.

Analysis and Design of the NASA Langley Cryogenic Pressure Box

NASA Technical Reports Server (NTRS)

Glass, David E.; Stevens, Jonathan C.; Vause, R. Frank; Winn, Peter M.; Maguire, James F.; Driscoll, Glenn C.; Blackburn, Charles L.; Mason, Brian H.

1999-01-01

A cryogenic pressure box was designed and fabricated for use at NASA Langley Research Center (LaRC) to subject 72 in. x 60 in. curved panels to cryogenic temperatures and biaxial tensile loads. The cryogenic pressure box is capable of testing curved panels down to -423 F (20K) with 54 psig maximum pressure on the concave side, and elevated temperatures and atmospheric pressure on the convex surface. The internal surface of the panel is cooled by high pressure helium as that is cooled to -423 F by liquid helium heat exchangers. An array of twelve independently controlled fans circulate the high pressure gaseous helium to provide uniform cooling on the panel surface. The load introduction structure, consisting of four stainless steel load plates and numerous fingers attaching the load plates to the test panel, is designed to introduce loads into the test panel that represent stresses that will he observed in the actual tank structure. The load plates are trace cooled with liquid nitrogen to reduce thermal gradients that may result in bending the load plates, and thus additional stresses in the test panel. The design of the cryogenic systems, load introduction structure, and control system are discussed in this report.

Toxicity of chromated copper arsenate (CCA)-treated wood to non-target marine fouling communities in Langstone Harbour, Portsmouth, UK.

PubMed

Brown, C J; Eaton, R A

2001-04-01

The effect of the anti-marine-borer timber preservative chromated copper arsenate (CCA) (a pressure impregnated solution of copper, chromium and arsenic compounds) on non-target marine fouling animals was investigated during a subtidal exposure trial. Panels of Scots pine treated to target retentions of 12, 24 and 48 kg CCA per m-3 of wood, plus untreated controls were submerged at a coastal site on the south coast of the UK for 6, 12 and 18 months. After each exposure period the fouling communities that formed on the surface of panels were assessed both qualitatively and quantitatively. Community structure was similar on panels treated to the three CCA loadings, but was significantly different from community structure on untreated panels. The total number of species (species richness) was similar on all panels, although the number of individual organisms attached to the surface of panels was significantly higher on CCA-treated panels than on untreated panels. k-dominance curves revealed that the difference in numbers of individuals between CCA-treated and untreated panels was caused by higher numbers of the dominant species (Elminius modestus, Hydroides ezoensis, and Electra pilosa) on CCA-treated panels. Other species were present in similar numbers on panels of all treatments. Results indicate that there are no detrimental toxic effects to epibiota caused by the presence of CCA preservative within the matrix of the wood at any of the treatment levels. Differences in community structure between CCA-treated and untreated panels may be due to enhanced larval settlement on CCA-treated timber by some species as a result of modifications to the surface properties of the timber by the CCA preservative.

A conceptual design study of point focusing thin-film solar concentrators

NASA Technical Reports Server (NTRS)

1981-01-01

Candidates for reflector panel design concepts, including materials and configurations, were identified. The large list of candidates was screened and reduced to the five most promising ones. Cost and technical factors were used in making the final choices for the panel conceptual design, which was a stiffened steel skin substrate with a bonded, acrylic overcoated, aluminized polyester film reflective surface. Computer simulations were run for the concentrator optics using the selected panel design, and experimentally determined specularity and reflectivity values. Intercept factor curves and energy to the aperture curves were produced. These curves indicate that surface errors of 2 mrad (milliradians) or less would be required to capture the desired energy for a Brayton cycle 816 C case. Two test panels were fabricated to demonstrate manufacturability and optically tested for surface error. Surface errors in the range of 1.75 mrad and 2.2 mrad were measured.

Development of an optical inspection platform for surface defect detection in touch panel glass

NASA Astrophysics Data System (ADS)

Chang, Ming; Chen, Bo-Cheng; Gabayno, Jacque Lynn; Chen, Ming-Fu

2016-04-01

An optical inspection platform combining parallel image processing with high resolution opto-mechanical module was developed for defect inspection of touch panel glass. Dark field images were acquired using a 12288-pixel line CCD camera with 3.5 µm per pixel resolution and 12 kHz line rate. Key features of the glass surface were analyzed by parallel image processing on combined CPU and GPU platforms. Defect inspection of touch panel glass, which provided 386 megapixel image data per sample, was completed in roughly 5 seconds. High detection rate of surface scratches on the touch panel glass was realized with minimum defects size of about 10 µm after inspection. The implementation of a custom illumination source significantly improved the scattering efficiency on the surface, therefore enhancing the contrast in the acquired images and overall performance of the inspection system.

Evaluation of the constant pressure panel method (CPM) for unsteady air loads prediction

NASA Technical Reports Server (NTRS)

Appa, Kari; Smith, Michael J. C.

1988-01-01

This paper evaluates the capability of the constant pressure panel method (CPM) code to predict unsteady aerodynamic pressures, lift and moment distributions, and generalized forces for general wing-body configurations in supersonic flow. Stability derivatives are computed and correlated for the X-29 and an Oblique Wing Research Aircraft, and a flutter analysis is carried out for a wing wind tunnel test example. Most results are shown to correlate well with test or published data. Although the emphasis of this paper is on evaluation, an improvement in the CPM code's handling of intersecting lifting surfaces is briefly discussed. An attractive feature of the CPM code is that it shares the basic data requirements and computational arrangements of the doublet lattice method. A unified code to predict unsteady subsonic or supersonic airloads is therefore possible.

Coating and curing apparatus and methods

DOEpatents

Brophy, Brenor L.; Gonsalves, Peter R.; Maghsoodi, Sina; Colson, Thomas E.; Yang, Yu S.; Abrams, Ze'ev R.

2016-04-19

Disclosed is a coating apparatus including flow coating and roll-coating that may be used for uniform sol-gel coating of substrates such as glass, solar panels, windows or part of an electronic display. Also disclosed are methods for substrate preparation, flow coating and roll coating. Lastly, systems and methods for curing sol-gel coatings deposited onto the surface of glass substrates using high temperature air-knives, infrared emitters and direct heat applicators are disclosed.

Experimental study of surface pattern effects on the propulsive performance and wake of a bio-inspired pitching panel

NASA Astrophysics Data System (ADS)

King, Justin; Kumar, Rajeev; Green, Melissa

2016-11-01

Force measurements and stereoscopic particle image velocimetry (PIV) were used to characterize the propulsive performance and wake structure of rigid, bio-inspired trapezoidal pitching panels. In the literature, it has been demonstrated that quantities such as thrust coefficient and propulsive efficiency are affected by changes in the surface characteristics of a pitching panel or foil. More specifically, the variation of surface pattern produces significant changes in wake structure and dynamics, especially in the distribution of vorticity in the wake. Force measurements and PIV data were collected for multiple surface patterns chosen to mimic fish surface morphology over a Strouhal number range of 0.17 to 0.56. Performance quantities are compared with the three-dimensional vortex wake structure for both the patterned and smooth panels to determine the nature and magnitude of surface pattern effects in terms of thrust produced, drag reduced, and wake vortices reshaped and reorganized. This work was supported by the Office of Naval Research under ONR Award No. N00014-14-1-0418.

Low-Melt Poly(Amic Acids) and Polyimides and Their Uses

NASA Technical Reports Server (NTRS)

Parrish, Clyde F. (Inventor); Jolley, Scott T. (Inventor); Gibson, Tracy L. (Inventor); Williams, Martha K. (Inventor); Parks, Steven L. (Inventor)

2014-01-01

Provided are low-melt polyimides and poly(amic acids) (PAAs) for use in repair of electrical wire insulation, flat or ribbon wire harnesses, and flat surfaces comprised of high-performance polymers such as inflatables or solar panels applications. Also provided are methods and devices for repair of electrical insulation.

Low-Melt Poly(amic Acids) and Polyimides and Their Uses

NASA Technical Reports Server (NTRS)

Jolley, Scott T. (Inventor); Gibson, Tracy L. (Inventor); Williams, Martha K. (Inventor); Parrish, Clyde F. (Inventor); Parks, Steven L. (Inventor)

2015-01-01

Provided are low-melt polyimides and poly(amic acids) (PAAs) for use in repair of electrical wire insulation, flat or ribbon wire harnesses, and flat surfaces comprised of high-performance polymers such as inflatables or solar panels applications. Also provided are methods and devices for repair of electrical insulation.

Thermal stress analysis of reusable surface insulation for shuttle

NASA Technical Reports Server (NTRS)

Ojalvo, I. U.; Levy, A.; Austin, F.

1974-01-01

An iterative procedure for accurately determining tile stresses associated with static mechanical and thermally induced internal loads is presented. The necessary conditions for convergence of the method are derived. An user-oriented computer program based upon the present method of analysis was developed. The program is capable of analyzing multi-tiled panels and determining the associated stresses. Typical numerical results from this computer program are presented.

Aerodynamic analysis of three advanced configurations using the TranAir full-potential code

NASA Technical Reports Server (NTRS)

Madson, M. D.; Carmichael, R. L.; Mendoza, J. P.

1989-01-01

Computational results are presented for three advanced configurations: the F-16A with wing tip missiles and under wing fuel tanks, the Oblique Wing Research Aircraft, and an Advanced Turboprop research model. These results were generated by the latest version of the TranAir full potential code, which solves for transonic flow over complex configurations. TranAir embeds a surface paneled geometry definition in a uniform rectangular flow field grid, thus avoiding the use of surface conforming grids, and decoupling the grid generation process from the definition of the configuration. The new version of the code locally refines the uniform grid near the surface of the geometry, based on local panel size and/or user input. This method distributes the flow field grid points much more efficiently than the previous version of the code, which solved for a grid that was uniform everywhere in the flow field. TranAir results are presented for the three configurations and are compared with wind tunnel data.

Transducer senses displacements of panels subjected to vibration

NASA Technical Reports Server (NTRS)

Pea, R. O.

1965-01-01

Inductive vibration sensor measures the surface displacement of nonferrous metal panels subjected to vibration or flutter. This transducer does not make any physical contact with the test panel when measuring.

Viscous-Inviscid Methods in Unsteady Aerodynamic Analysis of Bio-Inspired Morphing Wings

NASA Astrophysics Data System (ADS)

Dhruv, Akash V.

Flight has been one of the greatest realizations of human imagination, revolutionizing communication and transportation over the years. This has greatly influenced the growth of technology itself, enabling researchers to communicate and share their ideas more effectively, extending the human potential to create more sophisticated systems. While the end product of a sophisticated technology makes our lives easier, its development process presents an array of challenges in itself. In last decade, scientists and engineers have turned towards bio-inspiration to design more efficient and robust aerodynamic systems to enhance the ability of Unmanned Aerial Vehicles (UAVs) to be operated in cluttered environments, where tight maneuverability and controllability are necessary. Effective use of UAVs in domestic airspace will mark the beginning of a new age in communication and transportation. The design of such complex systems necessitates the need for faster and more effective tools to perform preliminary investigations in design, thereby streamlining the design process. This thesis explores the implementation of numerical panel methods for aerodynamic analysis of bio-inspired morphing wings. Numerical panel methods have been one of the earliest forms of computational methods for aerodynamic analysis to be developed. Although the early editions of this method performed only inviscid analysis, the algorithm has matured over the years as a result of contributions made by prominent aerodynamicists. The method discussed in this thesis is influenced by recent advancements in panel methods and incorporates both viscous and inviscid analysis of multi-flap wings. The surface calculation of aerodynamic coefficients makes this method less computationally expensive than traditional Computational Fluid Dynamics (CFD) solvers available, and thus is effective when both speed and accuracy are desired. The morphing wing design, which consists of sequential feather-like flaps installed over the upper and lower surfaces of a standard airfoil, proves to be an effective alternative to standard control surfaces by increasing the flight capability of bird-scale UAVs. The results obtained for this wing design under various flight and flap configurations provide insight into its aerodynamic behavior, which enhance the maneuverability and controllability. The overall method acts as an important tool to create an aerodynamic database to develop a distributed control system for autonomous operation of the multi-flap morphing wing, supporting the use of viscous-inviscid methods as a tool in rapid aerodynamic analysis.

Characterization of structural response to hypersonic boundary-layer transition

DOE PAGES

Riley, Zachary B.; Deshmukh, Rohit; Miller, Brent A.; ...

2016-05-24

The inherent relationship between boundary-layer stability, aerodynamic heating, and surface conditions makes the potential for interaction between the structural response and boundary-layer transition an important and challenging area of study in high-speed flows. This paper phenomenologically explores this interaction using a fundamental two-dimensional aerothermoelastic model under the assumption of an aluminum panel with simple supports. Specifically, an existing model is extended to examine the impact of transition onset location, transition length, and transitional overshoot in heat flux and fluctuating pressure on the structural response of surface panels. Transitional flow conditions are found to yield significantly increased thermal gradients, and theymore » can result in higher maximum panel temperatures compared to turbulent flow. Results indicate that overshoot in heat flux and fluctuating pressure reduces the flutter onset time and increases the strain energy accumulated in the panel. Furthermore, overshoot occurring near the midchord can yield average temperatures and peak displacements exceeding those experienced by the panel subject to turbulent flow. Lastly, these results suggest that fully turbulent flow does not always conservatively predict the thermo-structural response of surface panels.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anggoro, Didi Dwi, E-mail: anggorophd@gmail.com; Kristiana, Nunung, E-mail: nuna.c631@gmail.com

Ballistic protection equipment, such as a bulletproof vest, is a soldier’s most important means of preserving life and survivability in extreme combat conditions. The bulletproof vests are designed to protect the user’s chest from injury without disturbing the ability to perform his duties. Aromatic polyamide or aramid fibers known under the trade name Kevlar, Trawon and so is synthetic fiber materials commonly used in the manufacture of bulletproof vests. This synthetic fibers have high tensile strength and ductility. Kevlar is expensive and imported material. In this study, will introduce local natural raw materials, ramie fiber (Boehmeria nivea) which is cheapermore » and environmentally friendly. It has enough tenacity and tensile strength as a bulletproof vest. This experiment uses two panels, there are Panel A as front surface of Panel B. Panel A is a combination of ramie and epoxide matrix, while panel B is only ramie. From several variations of experimental combinations between Panel A and Panel B, optimal combination obtained with 16 layers of panel A and 31-34 layers of panel B which is able to protect againts cal. 7.65 mm × 17 mm (.32 ACP) bullet fired through pistol .32 Pindad from a distance of 20 meters. Panel with a size of 20 cm × 20 cm has a total thickness between 12,922 to13,745 mm and a total weight between 506,26 to 520,926gram. Scanning electron microscopy (SEM) observations indicated that the porosity and surface area of the ramie fiber is smooth, fiber surfaces showed topography with micropores. SEM also showed well-arranged structure of fibers bonding. Energy Dispersive X-ray (EDX) analysis indicated 100 % carbon contents in ramie fiber. Test result indicates that panel from composite ramie-epoxide can reach the level 1of International Standard of NIJ - 010104. Compared to panel from polyester fiber, the panel from composite ramie-epoxide (0,50-0,52 kg) is lighter weight than panel polyester fiber (1,642 kg)« less

Combination of natural fiber Boehmeria nivea (ramie) with matrix epoxide for bullet proof vest body armor

NASA Astrophysics Data System (ADS)

Anggoro, Didi Dwi; Kristiana, Nunung

2015-12-01

Ballistic protection equipment, such as a bulletproof vest, is a soldier's most important means of preserving life and survivability in extreme combat conditions. The bulletproof vests are designed to protect the user's chest from injury without disturbing the ability to perform his duties. Aromatic polyamide or aramid fibers known under the trade name Kevlar, Trawon and so is synthetic fiber materials commonly used in the manufacture of bulletproof vests. This synthetic fibers have high tensile strength and ductility. Kevlar is expensive and imported material. In this study, will introduce local natural raw materials, ramie fiber (Boehmeria nivea) which is cheaper and environmentally friendly. It has enough tenacity and tensile strength as a bulletproof vest. This experiment uses two panels, there are Panel A as front surface of Panel B. Panel A is a combination of ramie and epoxide matrix, while panel B is only ramie. From several variations of experimental combinations between Panel A and Panel B, optimal combination obtained with 16 layers of panel A and 31-34 layers of panel B which is able to protect againts cal. 7.65 mm × 17 mm (.32 ACP) bullet fired through pistol .32 Pindad from a distance of 20 meters. Panel with a size of 20 cm × 20 cm has a total thickness between 12,922 to13,745 mm and a total weight between 506,26 to 520,926gram. Scanning electron microscopy (SEM) observations indicated that the porosity and surface area of the ramie fiber is smooth, fiber surfaces showed topography with micropores. SEM also showed well-arranged structure of fibers bonding. Energy Dispersive X-ray (EDX) analysis indicated 100 % carbon contents in ramie fiber. Test result indicates that panel from composite ramie-epoxide can reach the level 1of International Standard of NIJ - 010104. Compared to panel from polyester fiber, the panel from composite ramie-epoxide (0,50-0,52 kg) is lighter weight than panel polyester fiber (1,642 kg).

Prediction of non-cavitation propeller noise in time domain

NASA Astrophysics Data System (ADS)

Ye, Jin-Ming; Xiong, Ying; Xiao, Chang-Run; Bi, Yi

2011-09-01

The blade frequency noise of non-cavitation propeller in a uniform flow is analyzed in time domain. The unsteady loading (dipole source) on the blade surface is calculated by a potential-based surface panel method. Then the time-dependent pressure data is used as the input for Ffowcs Williams-Hawkings formulation to predict the acoustics pressure. The integration of noise source is performed over the true blade surface rather than the nothickness blade surface, and the effect of hub can be considered. The noise characteristics of the non-cavitation propeller and the numerical discretization forms are discussed.

Time-Domain Method for Computing Forces and Moments Acting on Three Dimensional Surface-Piercing Ship Hulls with Forward Speed.

DTIC Science & Technology

1980-09-01

where 4BD represents the instantaneous effect of the body, while OFS represents the free surface disturbance generated by the body over all previous...acceleration boundary condition. This deter- mines the time-derivative of the body-induced component of the flow, 4BD (as well as OBD through integration...panel with uniform density ei acting over a surface of area Ai is replaced by a single point source with strength s i(t) - A i(a i(t n ) + (t-t n ) G( td

Elevated-Temperature Tests Under Static and Aerodynamic Conditions on Honeycomb-Core Sandwich Panels

NASA Technical Reports Server (NTRS)

Groen, Joseph M.; Johnson, Aldie E., Jr.

1959-01-01

Stainless-steel honeycomb-core sandwich panels which differed primarily in skin thicknesses were tested at elevated temperatures under static and aerodynamic conditions. The results of these tests were evaluated to determine the insulating effectiveness and structural integrity of the panels. The static radiant-heating tests were performed in front of a quartz-tube radiant heater at panel skin temperatures up to 1,5000 F. The aerodynamic tests were made in a Mach 1.4 heated blowdown wind tunnel. The tunnel temperature was augmented by additional heat supplied by a radiant heater which raised the panel surface temperature above 8000 F during air flow. Static radiant-heating tests of 2 minutes duration showed that all the panels protected the load-carrying structure about equally well. Thin-skin panels showed an advantage for this short-time test over thick-skin panels from a standpoint of weight against insulation. Permanent inelastic strains in the form of local buckles over each cell of the honeycomb core caused an increase in surface roughness. During the aero- dynamic tests all of the panels survived with little or no damage, and panel flutter did not occur.

Prediction of the thermal environment and thermal response of simple panels exposed to radiant heat

NASA Technical Reports Server (NTRS)

Turner, Travis L.; Ash, Robert L.

1989-01-01

A method of predicting the radiant heat flux distribution produced by a bank of tubular quartz heaters was applied to a radiant system consisting of a single unreflected lamp irradiating a flat metallic incident surface. In this manner, the method was experimentally verified for various radiant system parameter settings and used as a source of input for a finite element thermal analysis. Two finite element thermal analyses were applied to a thermal system consisting of a thin metallic panel exposed to radiant surface heating. A two-dimensional steady-state finite element thermal analysis algorithm, based on Galerkin's Method of Weighted Residuals (GFE), was formulated specifically for this problem and was used in comparison to the thermal analyzers of the Engineering Analysis Language (EAL). Both analyses allow conduction, convection, and radiation boundary conditions. Differences in the respective finite element formulation are discussed in terms of their accuracy and resulting comparison discrepancies. The thermal analyses are shown to perform well for the comparisons presented here with some important precautions about the various boundary condition models. A description of the experiment, corresponding analytical modeling, and resulting comparisons are presented.

Flight service evaluation of Kevlar-49/epoxy composite panels in wide-bodied commercial transport aircraft

NASA Technical Reports Server (NTRS)

Stone, R. H.

1975-01-01

Kevlar-49 fairing panels were inspected and found to be performing satisfactorily after two years flight service on an Eastern and an Air Canada L-1011. Six panels are on each aircraft including sandwich and solid laminate wing-body panels, and 300 F service aft engine fairings. Some of the panels were removed from the aircraft to permit inspection of inner surfaces and fastener hole conditions. Minor defects such as surface cracks due to impact damage, small delaminated areas, elongation and fraying of fastener holes, were noted. None of these defects were considered serious enough to warrant corrective action in the opinion of airline personnel. The defects are typical for the most part of defects noted on similar fiberglass parts.

Study of the application of superplastically formed and diffusion bonded (SPF/DB) titanium structure to laminar flow control (LFC) wing design

NASA Technical Reports Server (NTRS)

Mcquilkin, F. T.

1979-01-01

Eighteen design concepts for a LFC wing cover, using various SPF/DB approaches, were developed. After evaluation of producibility, compatibility with LFC requirements, structural efficiency and fatigue requirements, three candidates were selected for fabrication of demonstration panels. Included were both sandwich and stiffened semi-sandwich panels with slotted and perforated surfaces. Subsequent to the evaluation of the three demonstration panels, one concept was selected for fabrication of a 0.3 x 1.0 meter (12 x 42 inch) feasibility panel. It was a stiffened, semi-sandwich panel with a slotted surface, designed to meet the requirements of the upper wing cover at the maximum wing bending moment of the baseline configuration.

Aerothermal Test of Thermal Protection Systems for X-33 Reusable Launch Vehicle

NASA Technical Reports Server (NTRS)

Sawyer, James Wayne; Hodge, Jefferson; Moore, Brad; Snyder, Kevin

1999-01-01

An array of metallic Thermal Protection System (TPS) panels developed for the windward surface of the X-33 vehicle was tested in the 8-Foot High Temperature Tunnel at the NASA Langley Research Center. These tests were the first aerothermal tests of an X-33 TPS array and the test results will be used to validate the TPS for the X-33 flight program. Specifically, the tests evaluated the structural and thermal performance of the TPS, the effectiveness of the high temperature seals between adjacent panels and the durability of the TPS under realistic aerothermal flight conditions. The effect of varying panel-to-panel step heights, intentional damage to the seals between adjacent panels, and the use of secondary seals were also investigated during the test program. The metallic TPS developed for the windward surface of the X-33, the blanket TPS developed to protect the leeward surfaces of the X-33, and the test program in the 8-Foot High Temperature Tunnel are presented and discussed.

Heat exchanger panel

NASA Technical Reports Server (NTRS)

Warburton, Robert E. (Inventor); Cuva, William J. (Inventor)

2005-01-01

The present invention relates to a heat exchanger panel which has broad utility in high temperature environments. The heat exchanger panel has a first panel, a second panel, and at least one fluid containment device positioned intermediate the first and second panels. At least one of the first panel and the second panel have at least one feature on an interior surface to accommodate the at least one fluid containment device. In a preferred embodiment, each of the first and second panels is formed from a high conductivity, high temperature composite material. Also, in a preferred embodiment, the first and second panels are joined together by one or more composite fasteners.

Characterizing the reflectivity of handheld display devices.

PubMed

Liu, Peter; Badano, Aldo

2014-08-01

With increased use of handheld and tablet display devices for viewing medical images, methods for consistently measuring reflectivity of the devices are needed. In this note, the authors report on the characterization of diffuse reflections for handheld display devices including mobile phones and tablets using methods recommended by the American Association of Physicists in Medicine Task Group 18 (TG18). The authors modified the diffuse reflectance coefficient measurement method outlined in the TG18 report. The authors measured seven handheld display devices (two phones and five tablets) and three workstation displays. The device was attached to a black panel with Velcro. To study the effect of the back surface on the diffuse reflectance coefficient, the authors created Styrofoam masks with different size square openings and placed it in front of the device. Overall, for each display device, measurements of illuminance and reflected luminance on the display screen were taken. The authors measured with no mask, with masks of varying size, and with display-size masks, and calculated the corresponding diffuse reflectance coefficient. For all handhelds, the diffuse reflectance coefficient measured with no back panel were lower than measurements performed with a mask. The authors found an overall increase in reflectivity as the size of the mask decreases. For workstations displays, diffuse reflectance coefficients were higher when no back panel was used, and higher than with masks. In all cases, as luminance increased, illuminance increased, but not at the same rate. Since the size of handheld displays is smaller than that of workstation devices, the TG18 method suffers from a dependency on illumination condition. The authors show that the diffuse reflection coefficients can vary depending on the nature of the back surface of the illuminating box. The variability in the diffuse coefficient can be as large as 20% depending on the size of the mask. For all measurements, both luminance and illuminance increased as the size of the display window decreased. The TG18 method does not account for this variability. The authors conclude that the method requires a definitive description of the back panel used in the light source setup. The methods described in the TG18 document may need to be improved to provide consistent comparisons of desktop monitors, phones, and tablets.

Application of water flowing PVC pipe and EPS foam bead as insulation for wall panel

NASA Astrophysics Data System (ADS)

Ali, Umi Nadiah; Nor, Norazman Mohamad; Yusuf, Mohammed Alias; Othman, Maidiana; Yahya, Muhamad Azani

2018-02-01

Malaysia located in tropical climate which have a typical temperature range between 21 °C to 36 °C. Due to this, air-conditioning system for buildings become a necessity to provide comfort to occupants. In order to reduce the energy consumption of the air-conditioning system, the transmission of heat from outdoor to indoor space should be kept as minimum as possible. This article discuss about a technology to resist heat transfer through concrete wall panel using a hybrid method. In this research, PVC pipe was embedded at the center of concrete wall panel while the EPS foam beads were added about 1% of the cement content in the concrete mix forming the outer layer of the wall panel. Water is regulated in the PVC pipe from the rainwater harvesting system. The aim of this study is to minimize heat transfer from the external environment into the building. Internal building temperature which indicated in BS EN ISO 7730 or ASHRAE Standard 55 where the comfort indoor thermal is below 25°C during the daytime. Study observed that the internal surface temperature of heat resistance wall panel is up to 3°C lower than control wall panel. Therefore, we can conclude that application of heat resistance wall panel can lead to lower interior building temperature.

Controlled study of mold growth and cleaning procedure on treated and untreated wet gypsum wallboard in an indoor environment.

PubMed

Krause, Michael; Geer, William; Swenson, Lonie; Fallah, Payam; Robbins, Coreen

2006-08-01

The basis for some common gypsum wallboard mold remediation practices was examined. The bottom inch of several gypsum wallboard panels was immersed in bottled drinking water; some panels were coated and others were untreated. The panels were examined and tested for a period of 8 weeks. This study investigated: (a) whether mold growth, detectable visually or with tape lift samples, occurs within 1 week on wet gypsum wallboard; (b) the types, timing, and extent of mold growth on wet gypsum wallboard; (c) whether mold growth is present on gypsum wallboard surfaces 6 inches from visible mold growth; (d) whether some commonly used surface treatments affect the timing of occurrence and rate of mold growth; and (e) if moldy but dried gypsum wallboard can be cleaned with simple methods and then sealed with common surface treatments so that residual mold particles are undetectable with typical surface sampling techniques. Mold growth was not detected visually or with tape lift samples after 1 week on any of the wallboard panels, regardless of treatment, well beyond the 24-48 hours often mentioned as the incubation period. Growth was detected at 2 weeks on untreated gypsum. Penicillium, Cladosporium, and Acremonium were early colonizers of untreated panels. Aspergillus, Epicoccum, Alternaria, and Ulocladium appeared later. Stachybotrys was not found. Mold growth was not detected more than 6 inches beyond the margin of visible mold growth, suggesting that recommendations to remove gypsum wallboard more than 1 foot beyond visible mold are excessive. The surface treatments resulted in delayed mold growth and reduced the area of mold growth compared with untreated gypsum wallboard. Results showed that simple cleaning of moldy gypsum wallboard was possible to the extent that mold particles beyond "normal trapping" were not found on tape lift samples. Thus, cleaning is an option in some situations where removal is not feasible or desirable. In cases where conditions are not similar to those of this study, or where large areas may be affected, a sample area could be cleaned and tested to verify that the cleaning technique is sufficient to reduce levels to background or normal trapping. These results are generally in agreement with laboratory studies of mold growth on, and cleaning of, gypsum wallboard.

21 CFR 660.43 - Potency test.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 7 2013-04-01 2013-04-01 false Potency test. 660.43 Section 660.43 Food and Drugs... STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Hepatitis B Surface Antigen § 660.43 Potency test... antibody in the appropriate sera of the reference panel by all test methods recommended by the manufacturer...

Study of advanced composite structural design concepts for an arrow wing supersonic cruise configuration

NASA Technical Reports Server (NTRS)

Turner, M. J.; Grande, D. L.

1978-01-01

Based on estimated graphite and boron fiber properties, allowable stresses and strains were established for advanced composite materials. Stiffened panel and conventional sandwich panel concepts were designed and analyzed, using graphite/polyimide and boron/polyimide materials. The conventional sandwich panel was elected as the structural concept for the modified wing structure. Upper and lower surface panels of the arrow wing structure were then redesigned, using high strength graphite/polyimide sandwich panels, retaining the titanium spars and ribs from the prior study. The ATLAS integrated analysis and design system was used for stress analysis and automated resizing of surface panels. Flutter analysis of the hybrid structure showed a significant decrease in flutter speed relative to the titanium wing design. The flutter speed was increased to that of the titanium design by selective increase in laminate thickness and by using graphite fibers with properties intermediate between high strength and high modulus values.

A Community Terrain-Following Ocean Modeling System (ROMS)

DTIC Science & Technology

2015-09-30

funded NOPP project titled: Toward the Development of a Coupled COAMPS-ROMS Ensemble Kalman filter and adjoint with a focus on the Indian Ocean and the...surface temperature and surface salinity daily averages for 31-Jan-2014. Similarly, Figure 3 shows the sea surface height averaged solution for 31-Jan... temperature (upper panel; Celsius) and surface salinity (lower panel) for 31-Jan-2014. The refined solution for the Hudson Canyon grid is overlaid on

Fabrication of hydrophobic compressed oil palm trunk surface by sol-gel process

NASA Astrophysics Data System (ADS)

Muzakir, Syafiqah; Salim, Nurjannah; Huda Abu Bakar, Nurul; Roslan, Rasidi; Sin, Lim Wan; Hashim, Rokiah

2018-04-01

Improvement of the robustness of hydrophobic surfaces is crucial to achieving commercial applications of these surfaces in such various areas as self-cleaning, water repellency and corrosion resistance. Compressed oil palm trunk (OPT) panel is one of potential product which can be used as panelling and indoor furniture application. By adding hydrophobic properties to compressed oil palm trunk panel might increase the application of compressed oil palm trunk especially for outdoor application. In this study, fabrication is using the sol-gel technique. Sol-gel was prepared by adding ethanol with Hexadecyl Trimethyl Ammonium Bromide (CTAB) solution with Tetraethyl Orthosilicate (TEOS) with surface modification of chlorotrimethylsilane (CTMS). The surface with hydrophobic coating was undergone surface analysis with contact angle machine with the aid of software SCA 20 and the determined of the morphology of surface with scanning electron microscope (SEM). The produced compressed oil palm trunk surfaces exhibited promising hydrophobic properties with a contact angle of 104° and the relatively better mechanical robustness.

In-Situ Wave Observations in the High Resolution Air-Sea Interaction DRI

DTIC Science & Technology

2008-09-30

Program ( CDIP ) Harvest buoy located in 204 m depth off Point Conception. The initial sea surface is assumed Gaussian and homogeneous, with spectral...of simulated sea surface elevation. Right panels: corresponding observed frequency-directional wave spectra (source: CDIP ). Upper panels: Typical

Test results for electron beam charging of flexible insulators and composites. [solar array substrates, honeycomb panels, and thin dielectric films

NASA Technical Reports Server (NTRS)

Staskus, J. V.; Berkopec, F. D.

1979-01-01

Flexible solar-array substrates, graphite-fiber/epoxy - aluminum honeycomb panels, and thin dielectric films were exposed to monoenergetic electron beams ranging in energy from 2 to 20 keV in the Lewis Research Center's geomagnetic-substorm-environment simulation facility to determine surface potentials, dc currents, and surface discharges. The four solar-array substrate samples consisted of Kapton sheet reinforced with fabrics of woven glass or carbon fibers. They represented different construction techniques that might be used to reduce the charge accumulation on the array back surface. Five honeycomb-panel samples were tested, two of which were representative of Voyager antenna materials and had either conductive or nonconductive painted surfaces. A third sample was of Navstar solar-array substrate material. The other two samples were of materials proposed for use on Intelsat V. All the honeycomb-panel samples had graphite-fiber/epoxy composite face sheets. The thin dielectric films were 2.54-micrometer-thick Mylar and 7.62-micrometer-thick Kapton.

A study on metallic thermal protection system panel for Reusable Launch Vehicle

NASA Astrophysics Data System (ADS)

Caogen, Yao; Hongjun, Lü; Zhonghua, Jia; Xinchao, Jia; Yan, Lu; Haigang, Li

2008-07-01

A Ni-based superalloy honeycomb thermal protection system (TPS) panel has been fabricated. And a curved Ni-based superalloy honeycomb sandwich has also been fabricated. The preliminary thermal insulation results of a fabricated Ni-based superalloy honeycomb TPS panel (the areal density of this panel is 6.7 kg /m2 and total height is 32 mm) indicate that the maximum temperature of the lower surfaces of the panel is lower than 150∘ C when the temperature of outer surface is held at 650∘ C for 30 min. The flatwise tensile strength and compressive properties of a fabricated Ni-based superalloy honeycomb sandwich coupon was studied at room temperature. A multilayered coating has been developed on the surface of the superalloy honeycomb TPS panel for environmental protection and thermal control. The oxidation weight-change results show that the weight change of the Ni-based superalloy honeycomb sandwich with the oxidation resistant coating is extremely small at 1100∘ C in air for 10 h. The emittance layer of the multilayered coating imparts an emittance in excess of 0.85 during exposure at 850∘ C, which was at least 14% greater than that of the substrate with oxidation resistant alone.

Anti-reflective coating for visible light using a silver nanodisc metasurface with a refractive index of less than 1.0

NASA Astrophysics Data System (ADS)

Yasuda, Hideki; Matsuno, Ryo; Koito, Naoki; Hosoda, Hidemasa; Tani, Takeharu; Naya, Masayuki

2017-12-01

Suppression of visible-light reflection from material surfaces is an important technology for many applications such as flat-panel displays, camera lenses, and solar panels. In this study, we developed an anti-reflective coating design based on a silver nanodisc metasurface. The effective refractive index of a 10-nm-thick monolayer of silver nanodiscs was less than 1.0, which enabled strong suppression of reflection from the underlying substrate. The nanodisc structure was easy to fabricate using a conventional roll-to-roll wet-coating method. The anti-reflective structure was fabricated over a large area.

Precision hole punching on composite fiber reinforced polymer panels

NASA Astrophysics Data System (ADS)

Abdullah, A. B.; Zain, M. S. M.; Chan, H. Y.; Samad, Z.

2017-12-01

Structural materials, such as composite panels, can only be assembled, and in most cases through the use of fasteners, which are fitted into the drilled holes. However, drilling is costly and time consuming, thus affecting productivity. This research aims to develop an alternative method to drilling. In this paper, the precision of the holes was measured and the effects of the die clearance to the areas around the holes were evaluated. Measurement and evaluation were performed based on the profile of the holes constructed using Alicona IFM, a 3D surface measurement technique. Results showed that punching is a potential alternative to drilling but still requires improvements.

A three dimensional unsteady iterative panel method with vortex particle wakes and boundary layer model for bio-inspired multi-body wings

NASA Astrophysics Data System (ADS)

Dhruv, Akash; Blower, Christopher; Wickenheiser, Adam M.

2015-03-01

The ability of UAVs to operate in complex and hostile environments makes them useful in military and civil operations concerning surveillance and reconnaissance. However, limitations in size of UAVs and communication delays prohibit their operation close to the ground and in cluttered environments, which increase risks associated with turbulence and wind gusts that cause trajectory deviations and potential loss of the vehicle. In the last decade, scientists and engineers have turned towards bio-inspiration to solve these issues by developing innovative flow control methods that offer better stability, controllability, and maneuverability. This paper presents an aerodynamic load solver for bio-inspired wings that consist of an array of feather-like flaps installed across the upper and lower surfaces in both the chord- and span-wise directions, mimicking the feathers of an avian wing. Each flap has the ability to rotate into both the wing body and the inbound airflow, generating complex flap configurations unobtainable by traditional wings that offer improved aerodynamic stability against gusting flows and turbulence. The solver discussed is an unsteady three-dimensional iterative doublet panel method with vortex particle wakes. This panel method models the wake-body interactions between multiple flaps effectively without the need to define specific wake geometries, thereby eliminating the need to manually model the wake for each configuration. To incorporate viscous flow characteristics, an iterative boundary layer theory is employed, modeling laminar, transitional and turbulent regions over the wing's surfaces, in addition to flow separation and reattachment locations. This technique enables the boundary layer to influence the wake strength and geometry both within the wing and aft of the trailing edge. The results obtained from this solver are validated using experimental data from a low-speed suction wind tunnel operating at Reynolds Number 300,000. This method enables fast and accurate assessment of aerodynamic loads for initial design of complex wing configurations compared to other methods available.

Quantum dots coupled ZnO nanowire-array panels and their photocatalytic activities.

PubMed

Liao, Yulong; Que, Wenxiu; Zhang, Jin; Zhong, Peng; Yuan, Yuan; Qiu, Xinku; Shen, Fengyu

2013-02-01

Fabrication and characterization of a heterojunction structured by CdS quantum dots@ZnO nanowire-array panels were presented. Firstly, ZnO nanowire-array panels were prepared by using a chemical bath deposition approach where wurtzite ZnO nanowires with a diameter of about 100 nm and 3 microm in length grew perpendicularly to glass substrate. Secondly, CdS quantum dots were deposited onto the surface of the ZnO nanowire-arrays by using successive ion layer absorption and reaction method, and the CdS shell/ZnO core heterojunction were thus obtained. Field emission scanning electron microscopy and transmission electron microscope were employed to characterize the morphological properties of the as-obtained CdS quantum dots@ZnO nanowire-array panels. X-ray diffraction was adopted to characterize the crystalline properties of the as-obtained CdS quantum dots@ZnO nanowire-array panels. Methyl orange was taken as a model compound to confirm the photocatalytic activities of the CdS shell/ZnO core heterojunction. Results indicate that CdS with narrow band gap not only acts as a visible-light sensitizer but also is responsible for an effective charge separation.

Heart Rhythm Monitoring in the Constellation Lunar and Launch/Landing EVA Suit: Recommendations from an Expert Panel

NASA Technical Reports Server (NTRS)

Scheuring, Richard A.; Hamilton, D.; Jones, J. A.; Alexander, D.

2008-01-01

Currently there are several physiological monitoring requirements for Extravehicular Activity (EVA) in the Human-Systems Interface Requirements (HSIR) document, including continuous heart rhythm monitoring. However, it is not known whether heart rhythm monitoring in the lunar surface space suit is a necessary capability for lunar surface operations or in launch/landing suit the event of a cabin depressurization enroute to or from the moon. Methods: Current US astronaut corps demographic information was provided to an expert panel of cardiovascular medicine experts, including specialists in electrophysiology, exercise physiology, interventional cardiology and arrhythmia. This information included averages for male/female age, body mass index (BMI), blood pressure, cholesterol, inflammatory markers, echocardiogram, ranges for coronary artery calcium (CAC) scores for long duration astronauts, and ranges for heart rate (HR) and metabolic (MET) rates obtained during microgravity and lunar EVA. Results: The panel determined that no uncontrolled hazard was likely to occur in the suit during lunar surface or contingency microgravity ops that would require ECG monitoring in the highly screened US astronaut population. However having the capability for rhythm monitoring inside the vehicle (IVA) was considered critical to manage an astronaut in distress. Discussion: Heart rate (HR) monitoring alone allows effective monitoring of astronaut health and function. Consequently, electrocardiographic (ECG) monitoring capability as a clinical tool is not essential in the lunar or launch/landing space suit. However, the panel considered that rhythm monitoring could be useful in certain clinical situations, it was not considered required for safe operations. Also, lunar vehicles should be required to have ECG monitoring capability with a minimum of 5-lead ECG (derived 12- lead) for IVA medical assessments.

Development of Electrostatically Clean Solar Array Panels

NASA Technical Reports Server (NTRS)

Stern, Theodore G.

2000-01-01

Certain missions require Electrostatically Clean Solar Array (ECSA) panels to establish a favorable environment for the operation of sensitive scientific instruments. The objective of this program was to demonstrate the feasibility of an ECSA panel that minimizes panel surface potential below 100mV in LEO and GEO charged particle environments, prevents exposure of solar cell voltage and panel insulating surfaces to the ambient environment, and provides an equipotential, grounded structure surrounding the entire panel. An ECSA panel design was developed that uses a Front Side Aperture-Shield (FSA) that covers all inter-cell areas with a single graphite composite laminate, composite edge clips for connecting the FSA to the panel substrate, and built-in tabs that interconnect the FSA to conductive coated coverglasses using a conductive adhesive. Analysis indicated the ability of the design to meet the ECSA requirements. Qualification coupons and a 0.5m x 0.5m prototype panel were fabricated and tested for photovoltaic performance and electrical grounding before and after exposure to acoustic and thermal cycling environments. The results show the feasibility of achieving electrostatic cleanliness with a small penalty in mass, photovoltaic performance and cost, with a design is structurally robust and compatible with a wide range of current solar panel technologies.

Factors Influencing the Accuracy of Aerodynamic Hinge-Moment Prediction

DTIC Science & Technology

1978-08-01

condition on the aft lifting surfaces and flaps. A new modeling technique for trailing-edge wake analysis using a potential- flow program based on the...control surface as depicLed in figure 21.. Three different models are used to simulate the flow on the wing, the flap, and the gaps. In the first two panel...ized sense, similar to that implemented in the FLEXSTAB program. The modeling of the wake on the side-edge gaps differs in the first two panel models

Material migration studies with an ITER first wall panel proxy on EAST

NASA Astrophysics Data System (ADS)

Ding, R.; Pitts, R. A.; Borodin, D.; Carpentier, S.; Ding, F.; Gong, X. Z.; Guo, H. Y.; Kirschner, A.; Kocan, M.; Li, J. G.; Luo, G.-N.; Mao, H. M.; Qian, J. P.; Stangeby, P. C.; Wampler, W. R.; Wang, H. Q.; Wang, W. Z.

2015-02-01

The ITER beryllium (Be) first wall (FW) panels are shaped to protect leading edges between neighbouring panels arising from assembly tolerances. This departure from a perfectly cylindrical surface automatically leads to magnetically shadowed regions where eroded Be can be re-deposited, together with co-deposition of tritium fuel. To provide a benchmark for a series of erosion/re-deposition simulation studies performed for the ITER FW panels, dedicated experiments have been performed on the EAST tokamak using a specially designed, instrumented test limiter acting as a proxy for the FW panel geometry. Carbon coated molybdenum plates forming the limiter front surface were exposed to the outer midplane boundary plasma of helium discharges using the new Material and Plasma Evaluation System (MAPES). Net erosion and deposition patterns are estimated using ion beam analysis to measure the carbon layer thickness variation across the surface after exposure. The highest erosion of about 0.8 µm is found near the midplane, where the surface is closest to the plasma separatrix. No net deposition above the measurement detection limit was found on the proxy wall element, even in shadowed regions. The measured 2D surface erosion distribution has been modelled with the 3D Monte Carlo code ERO, using the local plasma parameter measurements together with a diffusive transport assumption. Excellent agreement between the experimentally observed net erosion and the modelled erosion profile has been obtained.

Automatic detection method for mura defects on display film surface using modified Weber's law

NASA Astrophysics Data System (ADS)

Kim, Myung-Muk; Lee, Seung-Ho

2014-07-01

We propose a method that automatically detects mura defects on display film surfaces using a modified version of Weber's law. The proposed method detects mura defects regardless of their properties and shapes by identifying regions perceived by human vision as mura using the brightness of pixel and image distribution ratio of mura in an image histogram. The proposed detection method comprises five stages. In the first stage, the display film surface image is acquired and a gray-level shift performed. In the second and third stages, the image histogram is acquired and analyzed, respectively. In the fourth stage, the mura range is acquired. This is followed by postprocessing in the fifth stage. Evaluations of the proposed method conducted using 200 display film mura image samples indicate a maximum detection rate of ˜95.5%. Further, the results of application of the Semu index for luminance mura in flat panel display (FPD) image quality inspection indicate that the proposed method is more reliable than a popular conventional method.

Simulation of Surface Pressure Induced by Vortex/Body Interaction

NASA Astrophysics Data System (ADS)

He, M.; Islam, M.; Veitch, B.; Bose, N.; Colbourne, M. B.; Liu, P.

When a strong vortical wake impacts a structure, the pressure on the impacted surface sees large variations in its amplitude. This pressure fluctuation is one of the main sources causing severe structural vibration and hydrodynamic noise. Economical and effective prediction methods of the fluctuating pressure are required by engineers in many fields. This paper presents a wake impingement model (WIM) that has been incorporated into a panel method code, Propella, and its applications in simulations of a podded propeller wake impacting on a strut. Simulated strut surface pressure distributions and variations are compared with experimental data in terms of time-averaged components and phase-averaged components. The pressure comparisons show that the calculated results are in a good agreement with experimental data.

A Surface Panel Method for the Hydrodynamic Analysis of Ducted Propellers

DTIC Science & Technology

1987-01-01

Flow About Arbitrary Three-Dimensional Lifting Bodies," Technical Report MDC J5679-01, McDonnell Douglas Corp., Oct. 197. 32 Van Manen , J. D...to that developed by Van Houten (4] for use with his vortex of a control point is less than the radius of the true surface. lattice ducted propeller...Boswell, R. J. and Miller, M. L., "Unsteady Propeller Load- erlands, 1983. ing-Measurement, Correlation, with Theory and Parametric 4 Van Houten, R

Selective coating for solar panels. [using black chrome and black nickel

NASA Technical Reports Server (NTRS)

Mcdonald, G. E. (Inventor)

1977-01-01

The energy absorbing properties of solar heating panels are improved by depositing a black chrome coating of controlled thickness on a specially prepared surface of a metal substrate. The surface is prepared by depositing a dull nickel on the substrate, and the black chrome is plated on this low emittance surface to a thickness between 0.5 micron and 2.5 microns.

76 FR 31856 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Adoption of Control...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-02

... Flat Wood Paneling Surface Coating Processes AGENCY: Environmental Protection Agency (EPA). ACTION... by EPA's Control Techniques Guidelines (CTG) standards for flat wood paneling surface coating processes. EPA is approving this revision concerning the adoption of the EPA CTG requirements for flat wood...

Investigation to advance prediction techniques of the low-speed aerodynamics of V/STOL aircraft

NASA Technical Reports Server (NTRS)

Maskew, B.; Strash, D.; Nathman, J.; Dvorak, F. A.

1985-01-01

A computer program, VSAERO, has been applied to a number of V/STOL configurations with a view to advancing prediction techniques for the low-speed aerodynamic characteristics. The program couples a low-order panel method with surface streamline calculation and integral boundary layer procedures. The panel method--which uses piecewise constant source and doublet panels-includes an iterative procedure for wake shape and models boundary layer displacement effect using the source transpiration technique. Certain improvements to a basic vortex tube jet model were installed in the code prior to evaluation. Very promising results were obtained for surface pressures near a jet issuing at 90 deg from a flat plate. A solid core model was used in the initial part of the jet with a simple entrainment model. Preliminary representation of the downstream separation zone significantly improve the correlation. The program accurately predicted the pressure distribution inside the inlet on the Grumman 698-411 design at a range of flight conditions. Furthermore, coupled viscous/potential flow calculations gave very close correlation with experimentally determined operational boundaries dictated by the onset of separation inside the inlet. Experimentally observed degradation of these operational boundaries between nacelle-alone tests and tests on the full configuration were also indicated by the calculation. Application of the program to the General Dynamics STOL fighter design were equally encouraging. Very close agreement was observed between experiment and calculation for the effects of power on pressure distribution, lift and lift curve slope.

Decontamination Efficacy of Three Commercial-Off-The-Shelf (COTS) Sporicidal Disinfectants on Medium-Sized Panels Contaminated with Surrogate Spores of Bacillus anthracis

PubMed Central

Sabol, Jonathan P.

2014-01-01

In the event of a wide area release and contamination of a biological agent in an outdoor environment and to building exteriors, decontamination is likely to consume the Nation’s remediation capacity, requiring years to cleanup, and leading to incalculable economic losses. This is in part due to scant body of efficacy data on surface areas larger than those studied in a typical laboratory (5×10-cm), resulting in low confidence for operational considerations in sampling and quantitative measurements of prospective technologies recruited in effective cleanup and restoration response. In addition to well-documented fumigation-based cleanup efforts, agencies responsible for mitigation of contaminated sites are exploring alternative methods for decontamination including combinations of disposal of contaminated items, source reduction by vacuuming, mechanical scrubbing, and low-technology alternatives such as pH-adjusted bleach pressure wash. If proven effective, a pressure wash-based removal of Bacillus anthracis spores from building surfaces with readily available equipment will significantly increase the readiness of Federal agencies to meet the daunting challenge of restoration and cleanup effort following a wide-area biological release. In this inter-agency study, the efficacy of commercial-of-the-shelf sporicidal disinfectants applied using backpack sprayers was evaluated in decontamination of spores on the surfaces of medium-sized (∼1.2 m2) panels of steel, pressure-treated (PT) lumber, and brick veneer. Of the three disinfectants, pH-amended bleach, Peridox, and CASCAD evaluated; CASCAD was found to be the most effective in decontamination of spores from all three panel surface types. PMID:24940605

Recent developments in rotary-wing aerodynamic theory

NASA Technical Reports Server (NTRS)

Johnson, W.

1986-01-01

Current progress in the computational analysis of rotary-wing flowfields is surveyed, and some typical results are presented in graphs. Topics examined include potential theory, rotating coordinate systems, lifting-surface theory (moving singularity, fixed wing, and rotary wing), panel methods (surface singularity representations, integral equations, and compressible flows), transonic theory (the small-disturbance equation), wake analysis (hovering rotor-wake models and transonic blade-vortex interaction), limitations on computational aerodynamics, and viscous-flow methods (dynamic-stall theories and lifting-line theory). It is suggested that the present algorithms and advanced computers make it possible to begin working toward the ultimate goal of turbulent Navier-Stokes calculations for an entire rotorcraft.

Integration of a supersonic unsteady aerodynamic code into the NASA FASTEX system

NASA Technical Reports Server (NTRS)

Appa, Kari; Smith, Michael J. C.

1987-01-01

A supersonic unsteady aerodynamic loads prediction method based on the constant pressure method was integrated into the NASA FASTEX system. The updated FASTEX code can be employed for aeroelastic analyses in subsonic and supersonic flow regimes. A brief description of the supersonic constant pressure panel method, as applied to lifting surfaces and body configurations, is followed by a documentation of updates required to incorporate this method in the FASTEX code. Test cases showing correlations of predicted pressure distributions, flutter solutions, and stability derivatives with available data are reported.

Efficiency of geometric designs of flexible solar panels: mathematical simulation

NASA Astrophysics Data System (ADS)

Marciniak, Malgorzata; Hassebo, Yasser; Enriquez-Torres, Delfino; Serey-Roman, Maria Ignacia

2017-09-01

The purpose of this study is to analyze various surfaces of flexible solar panels and compare them to the traditional at panels mathematically. We evaluated the efficiency based on the integral formulas that involve flux. We performed calculations for flat panels with different positions, a cylindrical panel, conical panels with various opening angles and segments of a spherical panel. Our results indicate that the best efficiency per unit area belongs to particular segments of spherically-shaped panels. In addition, we calculated the optimal opening angle of a cone-shaped panel that maximizes the annual accumulation of the sun radiation per unit area. The considered shapes are presented below with a suggestion for connections of the cells.

Reducing the maladaptive attractiveness of solar panels to polarotactic insects.

PubMed

Horváth, Gábor; Blahó, Miklós; Egri, Adám; Kriska, György; Seres, István; Robertson, Bruce

2010-12-01

Human-made objects (e.g., buildings with glass surfaces) can reflect horizontally polarized light so strongly that they appear to aquatic insects to be bodies of water. Insects that lay eggs in water are especially attracted to such structures because these insects use horizontal polarization of light off bodies of water to find egg-laying sites. Thus, these sources of polarized light can become ecological traps associated with reproductive failure and mortality in organisms that are attracted to them and by extension with rapid population declines or collapse. Solar panels are a new source of polarized light pollution. Using imaging polarimetry, we measured the reflection-polarization characteristics of different solar panels and in multiple-choice experiments in the field we tested their attractiveness to mayflies, caddis flies, dolichopodids, and tabanids. At the Brewster angle, solar panels polarized reflected light almost completely (degree of polarization d ≈ 100%) and substantially exceeded typical polarization values for water (d ≈ 30-70%). Mayflies (Ephemeroptera), stoneflies (Trichoptera), dolichopodid dipterans, and tabanid flies (Tabanidae) were the most attracted to solar panels and exhibited oviposition behavior above solar panels more often than above surfaces with lower degrees of polarization (including water), but in general they avoided solar cells with nonpolarizing white borders and white grates. The highly and horizontally polarizing surfaces that had nonpolarizing, white cell borders were 10- to 26-fold less attractive to insects than the same panels without white partitions. Although solar panels can act as ecological traps, fragmenting their solar-active area does lessen their attractiveness to polarotactic insects. The design of solar panels and collectors and their placement relative to aquatic habitats will likely affect populations of aquatic insects that use polarized light as a behavioral cue. © 2010 Society for Conservation Biology.

Rubber-Modified Epoxy and Glass Laminates for Application to Naval Ship Structures.

DTIC Science & Technology

1983-09-01

more information. Two generic carboxy terminated butadiene acrylonitrile ( CTBN )-modified epoxy/glass cloth material systems have been characterized...versus Normal Impact Energy of 7781-Z6040/Fl55 .......... .................... 8 4 - Front Surface of CTBN -Modified Epoxy GRP Panel After 60 Impacts at...15 6 - Back Surface of CTBN -Modified Epoxy GRP Panel After 60 Impacts at 206 Foot-Pounds ..... .................. ... 16 7 - Back Surface of

Convective and global stability analysis of a Mach 5.8 boundary layer grazing a compliant surface

NASA Astrophysics Data System (ADS)

Dettenrieder, Fabian; Bodony, Daniel

2016-11-01

Boundary layer transition on high-speed vehicles is expected to be affected by unsteady surface compliance. The stability properties of a Mach 5.8 zero-pressure-gradient laminar boundary layer grazing a nominally-flat thermo-mechanically compliant panel is considered. The linearized compressible Navier-Stokes equations describe small amplitude disturbances in the fluid while the panel deformations are described by the Kirchhoff-Love plate equation and its thermal state by the transient heat equation. Compatibility conditions that couple disturbances in the fluid to those in the solid yield simple algebraic and robin boundary conditions for the velocity and thermal states, respectively. A local convective stability analysis shows that the panel can modify both the first and second Mack modes when, for metallic-like panels, the panel thickness exceeds the lengthscale δ99 Rex- 0 . 5 . A global stability analysis, which permits finite panel lengths with clamped-clamped boundary conditions, shows a rich eigenvalue spectrum with several branches. Unstable modes are found with streamwise-growing panel deformations leading to Mach wave-type radiation. Stable global modes are also found and have distinctly different panel modes but similar radiation patterns. Air Force Office of Scientific Research.

Program VSAERO theory document: A computer program for calculating nonlinear aerodynamic characteristics of arbitrary configurations

NASA Technical Reports Server (NTRS)

Maskew, Brian

1987-01-01

The VSAERO low order panel method formulation is described for the calculation of subsonic aerodynamic characteristics of general configurations. The method is based on piecewise constant doublet and source singularities. Two forms of the internal Dirichlet boundary condition are discussed and the source distribution is determined by the external Neumann boundary condition. A number of basic test cases are examined. Calculations are compared with higher order solutions for a number of cases. It is demonstrated that for comparable density of control points where the boundary conditions are satisfied, the low order method gives comparable accuracy to the higher order solutions. It is also shown that problems associated with some earlier low order panel methods, e.g., leakage in internal flows and junctions and also poor trailing edge solutions, do not appear for the present method. Further, the application of the Kutta conditions is extremely simple; no extra equation or trailing edge velocity point is required. The method has very low computing costs and this has made it practical for application to nonlinear problems requiring iterative solutions for wake shape and surface boundary layer effects.

Theoretical investigation of flutter of two-dimensional flat panels with one surface exposed to supersonic potential flow

NASA Technical Reports Server (NTRS)

Nelson, Herbert C; Cunningham, Herbert J

1956-01-01

A Rayleigh type analysis involving chosen modes of the panel as degrees of freedom is used to treat the flutter of a two-dimensional flat panel supported at its leading and trailing edges and subjected to a middle-plane tensile force. The panel has a supersonic stream passing over its upper surface and still air below. The aerodynamic forces due to the supersonic stream are obtained from the theory for linearized two-dimensional unsteady flow and the forces due to the still air are obtained from acoustical theory. In order to study the effect of increasing the number of modes in the analysis, two and then four modes are employed. The modes used are the first four natural modes of the panel in a vacuum with no tensile force acting. The analysis includes these variables: Mach number, structural damping, tensile force, density of the still air, and edge fixity (clamped and pinned). For certain combinations of these variables, stability boundaries are obtained which can be used to determine the panel thickness required to prevent flutter for any panel material and altitude.

Packaging, deployment, and panel design concepts for a truss-stiffened 7-panel precision deployable reflector with feed boom

NASA Technical Reports Server (NTRS)

Heard, Walter L., Jr.; Collins, Timothy J.; Dyess, James W.; Kenner, Scott; Bush, Harold G.

1993-01-01

A concept is presented for achieving a remotely deployable truss-stiffened reflector consisting of seven integrated sandwich panels that form the reflective surface, and an integrated feed boom. The concept has potential for meeting aperture size and surface precision requirements for some high-frequency microwave remote sensing applications. The packaged reflector/feed boom configuration is a self-contained unit that can be conveniently attached to a spacecraft bus. The package has a cylindrical envelope compatible with typical launch vehicle shrouds. Dynamic behavior of a deployed configuration having a 216-inch focal length and consisting of 80-inch-diameter, two-inch-thick panels is examined through finite-element analysis. Results show that the feed boom and spacecraft bus can have a large impact on the fundamental frequency of the deployed configuration. Two candidate rib-stiffened sandwich panel configurations for this application are described, and analytical results for panel mass and stiffness are presented. Results show that the addition of only a few rib stiffeners, if sufficiently deep, can efficiently improve sandwich panel stiffness.

Bayesian-based estimation of acoustic surface impedance: Finite difference frequency domain approach.

PubMed

Bockman, Alexander; Fackler, Cameron; Xiang, Ning

2015-04-01

Acoustic performance for an interior requires an accurate description of the boundary materials' surface acoustic impedance. Analytical methods may be applied to a small class of test geometries, but inverse numerical methods provide greater flexibility. The parameter estimation problem requires minimizing prediction vice observed acoustic field pressure. The Bayesian-network sampling approach presented here mitigates other methods' susceptibility to noise inherent to the experiment, model, and numerics. A geometry agnostic method is developed here and its parameter estimation performance is demonstrated for an air-backed micro-perforated panel in an impedance tube. Good agreement is found with predictions from the ISO standard two-microphone, impedance-tube method, and a theoretical model for the material. Data by-products exclusive to a Bayesian approach are analyzed to assess sensitivity of the method to nuisance parameters.

Re-design and fabrication of titanium multi-wall Thermal Protection System (TPS) test panels

NASA Technical Reports Server (NTRS)

Blair, W.; Meaney, J. E., Jr.; Rosenthal, H. A.

1984-01-01

The Titanium Multi-wall Thermal Protection System (TIPS) panel was re-designed to incorporate Ti-6-2-4-2 outer sheets for the hot surface, ninety degree side closures for ease of construction and through panel fastness for ease of panel removal. Thermal and structural tests were performed to verify the design. Twenty-five panels were fabricated and delivered to NASA for evaluation at Langley Research Center and Johnson Space Center.

Structural tests and development of a laminar flow control wing surface composite chordwise joint

NASA Technical Reports Server (NTRS)

Lineberger, L. B.

1984-01-01

The dramatic increases in fuel costs and the potential for periods of limited fuel availability provided the impetus to explore technologies to reduce transport aircraft fuel consumption. NASA sponsored the Aircraft Energy Efficiency (ACEE) program beginning in 1976 to develop technologies to improve fuel efficiency. The Lockheed-Georgia Company accomplished under NAS1-16235 Laminar-Flow-Control (LFC) Wing Panel Structural Design and Development (WSSD); design, manufacturing, and testing activities. An in-depth preliminary design of the baseline 1993 LFC wing was accomplished. A surface panel using the Lockheed graphite/epoxy integrated LFC wing box structural concept was designed. The concept was shown by analysis to be structurally efficient and cost effective. Critical details of the surface and surface joint was demonstrated by fabricating and testing complex, concept selection specimens. The Lockheed-Georgia Company accomplishments, Development of LFC Wind Surface Composite Structures (WSCS), are documented. Tests were conducted on two CV2 panels to verify the static tension and fatigue strength of LFC wing surface chordwise joints.

Research on Storm-Tide Disaster Losses in China Using a New Grey Relational Analysis Model with the Dispersion of Panel Data

PubMed Central

Yin, Kedong; Zhang, Ya; Li, Xuemei

2017-01-01

Owing to the difference of the sequences’ orders and the surface structure in the current panel grey relational models, research results will not be unique. In addition, individual measurement of indicators and objects and the subjectivity of combined weight would significantly weaken the effective information of panel data and reduce the reliability and accuracy of research results. Therefore, we propose the concept and calculation method of dispersion of panel data, establish the grey relational model based on dispersion of panel data (DPGRA), and prove that DPGRA exhibits the effective properties of uniqueness, symmetry, and normality. To demonstrate its applicability, the proposed DPGRA model is used to research on storm-tide disaster losses in China’s coastal areas. Comparing research results of three models, which are DPGRA, Euclidean distance grey relational model, and grey grid relational model, it was shown that DPGRA is more effective, feasible, and stable. It is indicated that DPGRA can entirely utilize the effective information of panel data; what’s more, it can not only handle the non-uniqueness of the grey relational model’s results but also improve the reliability and accuracy of research results. The research results are of great significance for coastal areas to focus on monitoring storm–tide disasters hazards, strengthen the protection measures of natural disasters, and improve the ability of disaster prevention and reduction. PMID:29104262

Research on Storm-Tide Disaster Losses in China Using a New Grey Relational Analysis Model with the Dispersion of Panel Data.

PubMed

Yin, Kedong; Zhang, Ya; Li, Xuemei

2017-11-01

Owing to the difference of the sequences' orders and the surface structure in the current panel grey relational models, research results will not be unique. In addition, individual measurement of indicators and objects and the subjectivity of combined weight would significantly weaken the effective information of panel data and reduce the reliability and accuracy of research results. Therefore, we propose the concept and calculation method of dispersion of panel data, establish the grey relational model based on dispersion of panel data (DPGRA), and prove that DPGRA exhibits the effective properties of uniqueness, symmetry, and normality. To demonstrate its applicability, the proposed DPGRA model is used to research on storm-tide disaster losses in China's coastal areas. Comparing research results of three models, which are DPGRA, Euclidean distance grey relational model, and grey grid relational model, it was shown that DPGRA is more effective, feasible, and stable. It is indicated that DPGRA can entirely utilize the effective information of panel data; what's more, it can not only handle the non-uniqueness of the grey relational model's results but also improve the reliability and accuracy of research results. The research results are of great significance for coastal areas to focus on monitoring storm-tide disasters hazards, strengthen the protection measures of natural disasters, and improve the ability of disaster prevention and reduction.

Predicting vibratory stresses from aero-acoustic loads

NASA Astrophysics Data System (ADS)

Shaw, Matthew D.

Sonic fatigue has been a concern of jet aircraft engineers for many years. As engines become more powerful, structures become more lightly damped and complex, and materials become lighter, stiffer, and more complicated, the need to understand and predict structural response to aeroacoustic loads becomes more important. Despite decades of research, vibration in panels caused by random pressure loads, such as those found in a supersonic jet, is still difficult to predict. The work in this research improves on current prediction methods in several ways, in particular for the structural response due to wall pressures induced by supersonic turbulent flows. First, solutions are calculated using time-domain input pressure loads that include shock cells and their interaction with turbulent flow. The solutions include both mean (static) and oscillatory components. Second, the time series of stresses are required for many fatigue assessment counting algorithms. To do this, a method is developed to compute time-dependent solutions in the frequency domain. The method is first applied to a single-degree-of-freedom system. The equations of motion are derived and solved in both the frequency domain and the time domain. The pressure input is a random (broadband) signal representative of jet flow. The method is then applied to a simply-supported beam vibrating in flexure using a line of pressure inputs computed with computational fluid dynamics (CFD). A modal summation approach is used to compute structural response. The coupling between the pressure field and the structure, through the joint acceptance, is reviewed and discussed for its application to more complicated structures. Results from the new method and from a direct time domain method are compared for method verification. Because the match is good and the new frequency domain method is faster computationally, it is chosen for use in a more complicated structure. The vibration of a two-dimensional panel loaded by jet nozzle discharge flow is addressed. The surface pressures calculated at Pratt and Whitney using viscous and compressible CFD are analyzed and compared to surface pressure measurements made at the United Technologies Research Center (UTRC). A structural finite element model is constructed to represent a flexible panel also used in the UTRC setup. The mode shapes, resonance frequencies, modal loss factors, and surface pressures are input into the solution method. Displacement time series and power spectral densities are computed and compared to measurement and show good agreement. The concept of joint acceptance is further addressed for two-dimensional plates excited by supersonic jet flow. Static and alternating stresses in the panel are also computed, and the most highly stressed modes are identified. The surface pressures are further analyzed in the wavenumber domain for insight into the physics of sonic fatigue. Most of the energy in the wall pressure wavenumber-frequency spectrum at subsonic speeds is in turbulent structures near the convective wavenumber. In supersonic flow, however, the shock region dominates the spectrum at low frequencies, but convective behavior is still dominant at higher frequencies. When the forcing function wavenumber energy overlaps the modal wavenumbers, the acceptance of energy by the structure from the flow field is greatest. The wavenumber analysis suggests a means of designing structures to minimize overlap of excitation and structural wavenumber peaks to minimize vibration and sonic fatigue.

Material migration studies with an ITER first wall panel proxy on EAST

DOE PAGES

Ding, R.; Pitts, R. A.; Borodin, D.; ...

2015-01-23

The ITER beryllium (Be) first wall (FW) panels are shaped to protect leading edges between neighbouring panels arising from assembly tolerances. This departure from a perfectly cylindrical surface automatically leads to magnetically shadowed regions where eroded Be can be re-deposited, together with co-deposition of tritium fuel. To provide a benchmark for a series of erosion/re-deposition simulation studies performed for the ITER FW panels, dedicated experiments have been performed on the EAST tokamak using a specially designed, instrumented test limiter acting as a proxy for the FW panel geometry. Carbon coated molybdenum plates forming the limiter front surface were exposed tomore » the outer midplane boundary plasma of helium discharges using the new Material and Plasma Evaluation System (MAPES). Net erosion and deposition patterns are estimated using ion beam analysis to measure the carbon layer thickness variation across the surface after exposure. The highest erosion of about 0.8 µm is found near the midplane, where the surface is closest to the plasma separatrix. No net deposition above the measurement detection limit was found on the proxy wall element, even in shadowed regions. The measured 2D surface erosion distribution has been modelled with the 3D Monte Carlo code ERO, using the local plasma parameter measurements together with a diffusive transport assumption. In conclusion, excellent agreement between the experimentally observed net erosion and the modelled erosion profile has been obtained.« less

Solar panel thermal cycling testing by solar simulation and infrared radiation methods

NASA Technical Reports Server (NTRS)

Nuss, H. E.

1980-01-01

For the solar panels of the European Space Agency (ESA) satellites OTS/MAROTS and ECS/MARECS the thermal cycling tests were performed by using solar simulation methods. The performance data of two different solar simulators used and the thermal test results are described. The solar simulation thermal cycling tests for the ECS/MARECS solar panels were carried out with the aid of a rotatable multipanel test rig by which simultaneous testing of three solar panels was possible. As an alternative thermal test method, the capability of an infrared radiation method was studied and infrared simulation tests for the ultralight panel and the INTELSAT 5 solar panels were performed. The setup and the characteristics of the infrared radiation unit using a quartz lamp array of approx. 15 sq and LN2-cooled shutter and the thermal test results are presented. The irradiation uniformity, the solar panel temperature distribution, temperature changing rates for both test methods are compared. Results indicate the infrared simulation is an effective solar panel thermal testing method.

Hypersonic panel flutter in a rarefied atmosphere

NASA Technical Reports Server (NTRS)

Resende, Hugo B.

1993-01-01

Panel flutter is a form of dynamic aeroelastic instability resulting from the interaction between motion of an aircraft structural panel and the aerodynamic loads exerted on that panel by air flowing past one of the faces. It differs from lifting surface flutter in the sense that it is not usually catastrophic, the panel's motion being limited by nonlinear membrane stresses produced by the transverse displacement. Above some critical airflow condition, the linear instability grows to a limit cycle . The present investigation studies panel flutter in an aerodynamic regime known as 'free molecule flow', wherein intermolecular collisions can be neglected and loads are caused by interactions between individual molecules and the bounding surface. After collision with the panel, molecules may be reflected specularly or reemitted in diffuse fashion. Two parameters characterize this process: the 'momentum accommodation coefficient', which is the fraction of the specularly reflected molecules; and the ratio between the panel temperature and that of the free airstream. This model is relevant to the case of hypersonic flight vehicles traveling at very high altitudes and especially for panels oriented parallel to the airstream or in the vehicle's lee. Under these conditions the aerodynamic shear stress turns out to be considerably larger than the surface pressures, and shear effects must be included in the model. This is accomplished by means of distributed longitudinal and bending loads. The former can cause the panel to buckle. In the example of a simply-supported panel, it turns out that the second mode of free vibration tends to dominate the flutter solution, which is carried out by a Galerkin analysis. Several parametric studies are presented. They include the effects of (1) temperature ratio; (2) momentum accommodation coefficient; (3) spring parameters, which are associated with how the panel is connected to adjacent structures; (4) a parameter which relates compressive end load to its value which would cause classical column buckling; (5) a parameter proportional to the pressure differential between the front and back faces; and (6) initial curvature. The research is completed by an investigation into the possibility of accounting for molecular collisions, which proves to be infeasible given the speeds of current mainframe supercomputers.

Electrodeposition Painting of Metal Substrates: Pinholing in Surface Films,

DTIC Science & Technology

1978-08-01

a bright surface and rubbed clean with a moist cloth to remove the fine dust of metal adhering to the surface, dried, degrea.ed and desmutted by...rubbing with mineral turpentine . This procedure conforms to Australian Standards AS 1580 (May 1975), ‘Pretreatment of Metal Test Panels’. 2.3...deposition, the panels were carefully washed with clean water to remove loosely adhering excess paint which resulted solely from contact of the panel with

Time-domain hybrid method for simulating large amplitude motions of ships advancing in waves

NASA Astrophysics Data System (ADS)

Liu, Shukui; Papanikolaou, Apostolos D.

2011-03-01

Typical results obtained by a newly developed, nonlinear time domain hybrid method for simulating large amplitude motions of ships advancing with constant forward speed in waves are presented. The method is hybrid in the way of combining a time-domain transient Green function method and a Rankine source method. The present approach employs a simple double integration algorithm with respect to time to simulate the free-surface boundary condition. During the simulation, the diffraction and radiation forces are computed by pressure integration over the mean wetted surface, whereas the incident wave and hydrostatic restoring forces/moments are calculated on the instantaneously wetted surface of the hull. Typical numerical results of application of the method to the seakeeping performance of a standard containership, namely the ITTC S175, are herein presented. Comparisons have been made between the results from the present method, the frequency domain 3D panel method (NEWDRIFT) of NTUA-SDL and available experimental data and good agreement has been observed for all studied cases between the results of the present method and comparable other data.

Structural and thermal testing of lightweight reflector panels

NASA Technical Reports Server (NTRS)

Mcgregor, J.; Helms, R.; Hill, T.

1992-01-01

The paper describes the test facility developed for testing large lightweight reflective panels with very accurate and stable surfaces, such as the mirror panels of composite construction developed for the NASA's Precision Segmented Reflector (PSR). Special attention is given to the panel construction and the special problems posed by the characteristics of these panels; the design of the Optical/Thermal Vacuum test facility for structural and thermal testing, developed at the U.S. AFPL; and the testing procedure. The results of the PSR panel test program to date are presented. The test data showed that the analytical approaches used for the panel design and for the prediction of the on-orbit panel behavior were adequate.

Structural and Acoustic Numerical Modeling of a Curved Composite Honeycomb Panel

NASA Technical Reports Server (NTRS)

Grosveld, Ferdinand W.; Buehrle, Ralph D.; Robinson, Jay H.

2001-01-01

The finite and boundary element modeling of the curved section of a composite honeycomb aircraft fuselage sidewall was validated for both structural response and acoustic radiation. The curved panel was modeled in the pre-processor MSC/PATRAN. Geometry models of the curved panel were constructed based on the physical dimensions of the test article. Material properties were obtained from the panel manufacturer. Finite element models were developed to predict the modal parameters for free and supported panel boundary conditions up to a frequency of 600 Hz. Free boundary conditions were simulated by providing soft foam support under the four comers of the panel or by suspending the panel from elastic bands. Supported boundary conditions were obtained by clamping the panel between plastic tubing seated in grooves along the perimeter of a stiff and heavy frame. The frame was installed in the transmission loss window of the Structural Acoustic Loads and Transmission (SALT) facility at NASA Langley Research Center. The structural response of the curved panel due to point force excitation was predicted using MSC/NASTRAN and the radiated sound was computed with COMET/Acoustics. The predictions were compared with the results from experimental modal surveys and forced response tests on the fuselage panel. The finite element models were refined and updated to provide optimum comparison with the measured modal data. Excellent agreement was obtained between the numerical and experimental modal data for the free as well as for the supported boundary conditions. Frequency response functions (FRF) were computed relating the input force excitation at one panel location to the surface acceleration response at five panel locations. Frequency response functions were measured at the same locations on the test specimen and were compared with the calculated FRF values. Good agreement was obtained for the real and imaginary parts of the transfer functions when modal participation was allowed up to 3000 Hz. The validated finite element model was used to predict the surface velocities due to the point force excitation. Good agreement was obtained between the spatial characteristics of the predicted and measured surface velocities. The measured velocity data were input into the acoustic boundary element code to compute the sound radiated by the panel. The predicted sound pressure levels in the far-field of the panel agreed well with the sound pressure levels measured at the same location.

Test and Analyses of a Composite Multi-Bay Fuselage Panel Under Uni-Axial Compression

NASA Technical Reports Server (NTRS)

Li, Jian; Baker, Donald J.

2004-01-01

A composite panel containing three stringers and two frames cut from a vacuum-assisted resin transfer molded (VaRTM) stitched fuselage article was tested under uni-axial compression loading. The stringers and frames divided the panel into six bays with two columns of three bays each along the compressive loading direction. The two frames were supported at the ends with pins to restrict the out-of-plane translation. The free edges of the panel were constrained by knife-edges. The panel was modeled with shell finite elements and analyzed with ABAQUS nonlinear solver. The nonlinear predictions were compared with the test results in out-of-plane displacements, back-to-back surface strains on stringer flanges and back-to-back surface strains at the centers of the skin-bays. The analysis predictions were in good agreement with the test data up to post-buckling.

Numerical simulation of wind loads on solar panels

NASA Astrophysics Data System (ADS)

Su, Kao-Chun; Chung, Kung-Ming; Hsu, Shu-Tsung

2018-05-01

Solar panels mounted on the roof of a building or ground are often vulnerable to strong wind loads. This study aims to investigate wind loads on solar panels using computational fluid dynamic (CFD). The results show good agreement with wind tunnel data, e.g. the streamwise distribution of mean surface pressure coefficient of a solar panel. Wind uplift for solar panels with four aspect ratios is evaluated. The effect of inclined angle and clearance (or height) of a solar panel is addressed. It is found that wind uplift of a solar panel increases when there is an increase in inclined angle and the clearance above ground shows an opposite effect.

Thermal and structural tests of a hydrogen cooled panel

NASA Technical Reports Server (NTRS)

Richard, C. E.; Duncan, J. D.; Gellersen, E. W.; Demogenes, C.

1972-01-01

An experimental evaluation of the thermal and structural performance of a hydrogen-cooled panel is presented. The panel, which was of brazed Inconel 625 and Inconel 718 construction, was designed for a heat flux of 100 BTU per second-foot squared and an external surface pressure of 100 psi.

75 FR 81555 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Allegheny County's...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-28

... Techniques Guidelines for Large Appliance and Metal Furniture; Flat Wood Paneling; Paper, Film, and Foil... appliance and metal furniture; flat wood paneling; and paper, film, and foil surface coating processes. In... Control Techniques Guidelines for Large Appliance and Metal Furniture; Flat Wood Paneling; Paper, Film...

A higher order panel method for linearized supersonic flow

NASA Technical Reports Server (NTRS)

Ehlers, F. E.; Epton, M. A.; Johnson, F. T.; Magnus, A. E.; Rubbert, P. E.

1979-01-01

The basic integral equations of linearized supersonic theory for an advanced supersonic panel method are derived. Methods using only linear varying source strength over each panel or only quadratic doublet strength over each panel gave good agreement with analytic solutions over cones and zero thickness cambered wings. For three dimensional bodies and wings of general shape, combined source and doublet panels with interior boundary conditions to eliminate the internal perturbations lead to a stable method providing good agreement experiment. A panel system with all edges contiguous resulted from dividing the basic four point non-planar panel into eight triangular subpanels, and the doublet strength was made continuous at all edges by a quadratic distribution over each subpanel. Superinclined panels were developed and tested on s simple nacelle and on an airplane model having engine inlets, with excellent results.

Vibration and stress analysis of soft-bonded shuttle insulation tiles. Modal analysis with compact widely space stringers

NASA Technical Reports Server (NTRS)

Ojalvo, I. U.; Austin, F.; Levy, A.

1974-01-01

An efficient iterative procedure is described for the vibration and modal stress analysis of reusable surface insulation (RSI) of multi-tiled space shuttle panels. The method, which is quite general, is rapidly convergent and highly useful for this application. A user-oriented computer program based upon this procedure and titled RESIST (REusable Surface Insulation Stresses) has been prepared for the analysis of compact, widely spaced, stringer-stiffened panels. RESIST, which uses finite element methods, obtains three dimensional tile stresses in the isolator, arrestor (if any) and RSI materials. Two dimensional stresses are obtained in the tile coating and the stringer-stiffened primary structure plate. A special feature of the program is that all the usual detailed finite element grid data is generated internally from a minimum of input data. The program can accommodate tile idealizations with up to 850 nodes (2550 degrees-of-freedom) and primary structure idealizations with a maximum of 10,000 degrees-of-freedom. The primary structure vibration capability is achieved through the development of a new rapid eigenvalue program named ALARM (Automatic LArge Reduction of Matrices to tridiagonal form).

Exact analytical formulae for linearly distributed vortex and source sheets in uence computation in 2D vortex methods

NASA Astrophysics Data System (ADS)

Kuzmina, K. S.; Marchevsky, I. K.; Ryatina, E. P.

2017-11-01

We consider the methodology of numerical schemes development for two-dimensional vortex method. We describe two different approaches to deriving integral equation for unknown vortex sheet intensity. We simulate the velocity of the surface line of an airfoil as the influence of attached vortex and source sheets. We consider a polygonal approximation of the airfoil and assume intensity distributions of free and attached vortex sheets and attached source sheet to be approximated with piecewise constant or piecewise linear (continuous or discontinuous) functions. We describe several specific numerical schemes that provide different accuracy and have a different computational cost. The study shows that a Galerkin-type approach to solving boundary integral equation requires computing several integrals and double integrals over the panels. We obtain exact analytical formulae for all the necessary integrals, which makes it possible to raise significantly the accuracy of vortex sheet intensity computation and improve the quality of velocity and vorticity field representation, especially in proximity to the surface line of the airfoil. All the formulae are written down in the invariant form and depend only on the geometric relationship between the positions of the beginnings and ends of the panels.

Laser Surface Preparation of Epoxy Composites for Secondary Bonding: Optimization of Ablation Depth

NASA Technical Reports Server (NTRS)

Palmieri, Frank L.; Hopkins, John; Wohl, Christopher J.; Lin, Yi; Connell, John W.; Belcher, Marcus A.; Blohowiak, Kay Y.

2015-01-01

Surface preparation has been identified as one of the most critical aspects of attaining predictable and reliable adhesive bonds. Energetic processes such as laser ablation or plasma treatment are amenable to automation and are easily monitored and adjusted for controlled surface preparation. A laser ablation process was developed to accurately remove a targeted depth of resin, approximately 0.1 to 20 micrometers, from a carbon fiber reinforced epoxy composite surface while simultaneously changing surface chemistry and creating micro-roughness. This work demonstrates the application of this process to prepare composite surfaces for bonding without exposing or damaging fibers on the surface. Composite panels were prepared in an autoclave and had a resin layer approximately 10 micrometers thick above the fiber reinforcement. These composite panels were laser surface treated using several conditions, fabricated into bonded panels and hygrothermally aged. Bond performance of aged, experimental specimens was compared with grit blast surface treated specimens using a modified double cantilever beam test that enabled accelerated saturation of the specimen with water. Comparison of bonded specimens will be used to determine how ablation depth may affect average fracture energies and failure modes.

Thermal Protection System with Staggered Joints

NASA Technical Reports Server (NTRS)

Simon, Xavier D. (Inventor); Robinson, Michael J. (Inventor); Andrews, Thomas L. (Inventor)

2014-01-01

The thermal protection system disclosed herein is suitable for use with a spacecraft such as a reentry module or vehicle, where the spacecraft has a convex surface to be protected. An embodiment of the thermal protection system includes a plurality of heat resistant panels, each having an outer surface configured for exposure to atmosphere, an inner surface opposite the outer surface and configured for attachment to the convex surface of the spacecraft, and a joint edge defined between the outer surface and the inner surface. The joint edges of adjacent ones of the heat resistant panels are configured to mate with each other to form staggered joints that run between the peak of the convex surface and the base section of the convex surface.

Static and aerothermal tests of a superalloy honeycomb prepackaged thermal protection system

NASA Technical Reports Server (NTRS)

Gorton, Mark P.; Shideler, John L.; Webb, Granville L.

1993-01-01

A reusable metallic thermal protection system has been developed for vehicles with maximum surface temperatures of up to 2000 F. An array of two 12- by 12-in. panels was subjected to radiant heating tests that simulated Space Shuttle entry temperature and pressure histories. Results indicate that this thermal protection system, with a mass of 2.201 lbm/ft(exp 2), can successfully prevent typical aluminum primary structure of an entry vehicle like the Space Shuttle from exceeding temperatures greater than 350 F at a location on the vehicle where the maximum surface temperature is 1900 F. A flat array of 20 panels was exposed to aerothermal flow conditions, at a Mach number of 6.75. The panels were installed in a worst-case orientation with the gaps between panels parallel to the flow. Results from the aerothermal tests indicated that convective heating occurred from hot gas flow in the gaps between the panels. Proposed design changes to prevent gap heating occurred from hot gas flow in the gaps between the panels. Proposed design changes to prevent gap heating include orienting panels so that gaps are not parallel to the flow and using a packaged, compressible gap-filler material between panels to block hot gas flow in the gaps.

Enhancing Convective Heat Transfer over a Surrogate Photovoltaic Panel

NASA Astrophysics Data System (ADS)

Fouladi, Fama

This research is particularly focused on studying heat transfer enhancement of a photovoltaic (PV) panel by putting an obstacle at the panel's windward edge. The heat transfer enhancement is performed by disturbing the airflow over the surface and increasing the heat and momentum transfer. Different objects such as triangular, square, rectangular, and discrete rectangular ribs and partial grids were applied at the leading edge of a surrogate PV panel and flow and the heat transfer of the panel are investigated experimentally. This approach was selected to expand understanding of effect of these different objects on the flow and turbulence structures over a flat surface by analyzing the flow comprehensively. It is observed that, a transverse object at the plate's leading edge would cause some flow blockage in the streamwise direction, but at the same time creates some velocity in the normal and cross stream directions. In addition to that, the obstacle generates some turbulence over the surface which persists for a long downstream distance. Also, among all studied objects, discrete rectangular ribs demonstrate the highest heat transfer rate enhancement (maximum Nu/Nu0 of 1.5). However, ribs with larger gap ratios are observed to be more effective at enhancing the heat transfer augmentation at closer distances to the rib, while at larger downstream distances from the rib, discrete ribs with smaller gap ratios are more effective. Furthermore, this work attempted to recognize the most influential flow parameters on the heat transfer enhancement of the surface. It is seen that the flow structure over a surface downstream of an object (flow separation-reattachment behaviour) has a significant effect on the heat transfer enhancement trend. Also, turbulence intensities are the most dominant parameters in enhancing the heat transfer rate from the surface; however, flow velocity (mostly normal velocity) is also an important factor.

Contact Angle of Drops Measured on Nontransparent Surfaces and Capillary Flow Visualized

NASA Technical Reports Server (NTRS)

Chao, David F.; Zhang, Nengli

2003-01-01

The spreading of a liquid on a solid surface is important for various practical processes, and contact-angle measurements provide an elegant method to characterize the interfacial properties of the liquid with the solid substrates. The complex physical processes occurring when a liquid contacts a solid play an important role in determining the performance of chemical processes and materials. Applications for these processes are in printing, coating, gluing, textile dyeing, and adhesives and in the pharmaceutical industry, biomedical research, adhesives, flat panel display manufacturing, surfactant chemistry, and thermal engineering.

CFD Simulations for Arc-Jet Panel Testing Capability Development Using Semi-Elliptical Nozzles

NASA Technical Reports Server (NTRS)

Gokcen, Tahir; Balboni, John A.; Hartman, G. Joseph

2016-01-01

This paper reports computational simulations in support of arc-jet panel testing capability development using semi-elliptical nozzles in a high enthalpy arc-jet facility at NASA Ames Research Center. Two different semi-elliptical nozzle configurations are proposed for testing panel test articles. Computational fluid dynamics simulations are performed to provide estimates of achievable panel surface conditions and useful test area for each configuration. The present analysis comprises three-dimensional simulations of the nonequilibrium flowfields in the semi-elliptical nozzles, test box and flowfield over the panel test articles. Computations show that useful test areas for the proposed two nozzle options are 20.32 centimeters by 20.32 centimeters (8 inches by 8 inches) and 43.18 centimeters by 43.18 centimeters (17 inches by 17 inches). Estimated values of the maximum cold-wall heat flux and surface pressure are 155 watts per centimeters squared and 39 kilopascals for the smaller panel test option, and 44 watts per centimeters squared and 7 kilopascals for the larger panel test option. Other important properties of the predicted flowfields are presented, and factors that limit the useful test area in the semi-free jet test configuration are discussed.

Comparisons of predicted steady-state levels in rooms with extended- and local-reaction bounding surfaces

NASA Astrophysics Data System (ADS)

Hodgson, Murray; Wareing, Andrew

2008-01-01

A combined beam-tracing and transfer-matrix model for predicting steady-state sound-pressure levels in rooms with multilayer bounding surfaces was used to compare the effect of extended- and local-reaction surfaces, and the accuracy of the local-reaction approximation. Three rooms—an office, a corridor and a workshop—with one or more multilayer test surfaces were considered. The test surfaces were a single-glass panel, a double-drywall panel, a carpeted floor, a suspended-acoustical ceiling, a double-steel panel, and glass fibre on a hard backing. Each test surface was modeled as of extended or of local reaction. Sound-pressure levels were predicted and compared to determine the significance of the surface-reaction assumption. The main conclusions were that the difference between modeling a room surface as of extended or of local reaction is not significant when the surface is a single plate or a single layer of material (solid or porous) with a hard backing. The difference is significant when the surface consists of multilayers of solid or porous material and includes a layer of fluid with a large thickness relative to the other layers. The results are partially explained by considering the surface-reflection coefficients at the first-reflection angles.

Surface Acoustic Wave Vibration Sensors for Measuring Aircraft Flutter

NASA Technical Reports Server (NTRS)

Wilson, William C.; Moore, Jason P.; Juarez, Peter D.

2016-01-01

Under NASA's Advanced Air Vehicles Program the Advanced Air Transport Technology (AATT) Project is investigating flutter effects on aeroelastic wings. To support that work a new method for measuring vibrations due to flutter has been developed. The method employs low power Surface Acoustic Wave (SAW) sensors. To demonstrate the ability of the SAW sensor to detect flutter vibrations the sensors were attached to a Carbon fiber-reinforced polymer (CFRP) composite panel which was vibrated at six frequencies from 1Hz to 50Hz. The SAW data was compared to accelerometer data and was found to resemble sine waves and match each other closely. The SAW module design and results from the tests are presented here.

Axial compression behaviour of reinforced wallettes fabricated using wood-wool cement panel

NASA Astrophysics Data System (ADS)

Noh, M. S. Md; Kamarudin, A. F.; Mokhatar, S. N.; Jaudin, A. R.; Ahmad, Z.; Ibrahim, A.; Muhamad, A. A.

2018-04-01

Wood-wool cement composite panel (WWCP) is one of wood based composite material that produced in a stable panel form and suitable to be used as building wall system to replace non-ecofriendly material such as brick and other masonry element. Heavy construction material such as brick requires more manpower and consume a lot of time to build the wall panel. WWCP is a lightweight material with a density range from 300 kg/m3 to 500 kg/m3 and also capable to support an imposed load from the building. This study reported on the axial compression behaviour of prefabricated reinforced wallettes constructed with wood-wool cement panel. A total of six specimens were fabricated using two layers of cross laminated WWCP bonded with normal mortar paste (Portland cement) at a mix ratio of 1:3 (cement : sand). As part of lifting mechanism, the wallettes were equipped with three steel reinforcement (T12) that embedded inside the core of wallettes. Three replicates of wallettes specimens with dimension 600 mm width and 600 mm length were fabricated without surface plaster and with 16 mm thickness of surface plaster. The wallettes were tested under axial compression load after 28 days of fabrication until failure. The result indicated that, the application of surface plaster significantly increases the loading capacity about 35 % and different orientation of the panels improve the bonding strength of the wall.

PAN AIR: A computer program for predicting subsonic or supersonic linear potential flows about arbitrary configurations using a higher order panel method. Volume 2: User's manual (version 3.0)

NASA Technical Reports Server (NTRS)

Sidwell, Kenneth W.; Baruah, Pranab K.; Bussoletti, John E.; Medan, Richard T.; Conner, R. S.; Purdon, David J.

1990-01-01

A comprehensive description of user problem definition for the PAN AIR (Panel Aerodynamics) system is given. PAN AIR solves the 3-D linear integral equations of subsonic and supersonic flow. Influence coefficient methods are used which employ source and doublet panels as boundary surfaces. Both analysis and design boundary conditions can be used. This User's Manual describes the information needed to use the PAN AIR system. The structure and organization of PAN AIR are described, including the job control and module execution control languages for execution of the program system. The engineering input data are described, including the mathematical and physical modeling requirements. Version 3.0 strictly applies only to PAN AIR version 3.0. The major revisions include: (1) inputs and guidelines for the new FDP module (which calculates streamlines and offbody points); (2) nine new class 1 and class 2 boundary conditions to cover commonly used modeling practices, in particular the vorticity matching Kutta condition; (3) use of the CRAY solid state Storage Device (SSD); and (4) incorporation of errata and typo's together with additional explanation and guidelines.

Highly stretchable, transparent ionic touch panel

NASA Astrophysics Data System (ADS)

Kim, Chong-Chan; Lee, Hyun-Hee; Oh, Kyu Hwan; Sun, Jeong-Yun

2016-08-01

Because human-computer interactions are increasingly important, touch panels may require stretchability and biocompatibility in order to allow integration with the human body. However, most touch panels have been developed based on stiff and brittle electrodes. We demonstrate an ionic touch panel based on a polyacrylamide hydrogel containing lithium chloride salts. The panel is soft and stretchable, so it can sustain a large deformation. The panel can freely transmit light information because the hydrogel is transparent, with 98% transmittance for visible light. A surface-capacitive touch system was adopted to sense a touched position. The panel can be operated under more than 1000% areal strain without sacrificing its functionalities. Epidermal touch panel use on skin was demonstrated by writing words, playing a piano, and playing games.

TranAir: A full-potential, solution-adaptive, rectangular grid code for predicting subsonic, transonic, and supersonic flows about arbitrary configurations. Theory document

NASA Technical Reports Server (NTRS)

Johnson, F. T.; Samant, S. S.; Bieterman, M. B.; Melvin, R. G.; Young, D. P.; Bussoletti, J. E.; Hilmes, C. L.

1992-01-01

A new computer program, called TranAir, for analyzing complex configurations in transonic flow (with subsonic or supersonic freestream) was developed. This program provides accurate and efficient simulations of nonlinear aerodynamic flows about arbitrary geometries with the ease and flexibility of a typical panel method program. The numerical method implemented in TranAir is described. The method solves the full potential equation subject to a set of general boundary conditions and can handle regions with differing total pressure and temperature. The boundary value problem is discretized using the finite element method on a locally refined rectangular grid. The grid is automatically constructed by the code and is superimposed on the boundary described by networks of panels; thus no surface fitted grid generation is required. The nonlinear discrete system arising from the finite element method is solved using a preconditioned Krylov subspace method embedded in an inexact Newton method. The solution is obtained on a sequence of successively refined grids which are either constructed adaptively based on estimated solution errors or are predetermined based on user inputs. Many results obtained by using TranAir to analyze aerodynamic configurations are presented.

Development Report for the 10 KW Sound Attenuation Program (Preproduction ’F’ Kit).

DTIC Science & Technology

1981-12-02

3.2 Panel Design The panels were to be constructed from solid aluminum sheet metal on all ex- ; terior surfaces and acoustic fiberglass or mineral ... wool bill overlayed with a synthetic film and encapsulated with perforated aluminum on the interior sur- faces. Per design, the acoustic panels on the

Decontamination Efficacy of Three Commercial Off-the-Shelf Sporicidal Agents on Medium-Sized Panels Contaminated with Surrogates of Bacillus anthracis

DTIC Science & Technology

2012-04-01

chlorine dioxide (CD) or vapor hydrogen peroxide ( VHP ). A wide-area release and contamination of building exteriors and the outdoors would likely...from the panels. Depending on the surface composition and the decontamination technology tested, viable spore recovery from the panels varied after

Wing Leading Edge Debris Analysis

NASA Technical Reports Server (NTRS)

Shah, Sandeep; Jerman, Gregory

2004-01-01

This is a slide presentation showing the Left Wing Leading Edge (WLE) heat damage observations: Heavy "slag" deposits on select RCC panels. Eroded and knife-edged RCC rib sections. Excessive overheating and slumping of carrier panel tiles. Missing or molten attachment bolts but intact bushing. Deposit mainly on "inside" RCC panel. Deposit on some fractured RCC surface

46 CFR 120.330 - Distribution panels and switchboards.

Code of Federal Regulations, 2010 CFR

2010-10-01

... INSTALLATION Power Sources and Distribution Systems § 120.330 Distribution panels and switchboards. (a) Each... vessel's wiring, must not have electrically unshielded or uninsulated surfaces. (k) Switchboards and...

Development of the technology for the fabrication of reliable laminar from control panels

NASA Technical Reports Server (NTRS)

Meade, L. E.; Kays, A. O.; Ferrill, R. S.; Young, H. R.

1977-01-01

Materials were assessed and fabrication techniques were developed for use in the manufacture of wing surface materials compatible with the application of both aluminum alloys and nonmetallic composites. The concepts investigated included perforations and slots in the metallic test panels and microporosity and perforations in the composite test panels. Perforations were produced in the metallic test panels by the electron beam process and slots were developed by controlled gaps between the metal sheets. Microporosity was produced in the composite test panels by the resin bleed process, and perforations were produced by the fugitive fiber technique. Each of these concepts was fabricated into test panels, and air flow tests were conducted on the panels.

Offset truss hex solar concentrator

NASA Technical Reports Server (NTRS)

White, John E. (Inventor); Sturgis, James D. (Inventor); Erikson, Raymond J. (Inventor); Waligroski, Gregg A. (Inventor); Scott, Michael A. (Inventor)

1991-01-01

A solar energy concentrator system comprises an offset reflector structure made up of a plurality of solar energy reflector panel sections interconnected with one another to form a piecewise approximation of a portion of a (parabolic) surface of revolution rotated about a prescribed focal axis. Each panel section is comprised of a plurality of reflector facets whose reflective surfaces effectively focus reflected light to preselected surface portions of the interior sidewall of a cylindrically shaped solar energy receiver. The longitudinal axis of the receiver is tilted at an acute angle with respect to the optical axis such that the distribution of focussed solar energy over the interior surface of the solar engine is optimized for dynamic solar energy conversion. Each reflector panel section comprises a flat, hexagonally shaped truss support framework and a plurality of beam members interconnecting diametrically opposed corners of the hexagonal framework recessed within which a plurality of (spherically) contoured reflector facets is disposed. The depth of the framework and the beam members is greater than the thickness of a reflector facet such that a reflector facet may be tilted (for controlling the effective focus of its reflected light through the receiver aperture) without protruding from the panel section.

Etude des defauts apparaissant dans les amenagements interieurs des avions d'affaires

NASA Astrophysics Data System (ADS)

Charette, Emilie

The evolution of the aeronautic industry led to the development of new materials for these high performance applications. Among other examples, composite sandwich structures are increasingly used for interior body panels of business airplanes. These structures are assembled and fixed to the fuselage using metallic inserts bonded inside the sandwich panels with an epoxy resin adhesive. A thin film of wood veneer covers the visible side of interior furniture in order to bring sophistication and esthetic to the interior design. However, due to multiple factors, surface defects frequently appear on the veneered side of the panel where inserts are located. Moreover the defects tend to appear months after the airplane delivery causing costly reparations. The sources of defects can be mechanical ( deformation due to an excessive tightening), chemical (shrinkage of the epoxy adhesive) or the result of hygrothermal exposition. It is therefore important to understand the source of such surface defects and ultimately prevent or control their appearance. The present thesis deals with defects from chemical and hygrothermal sources appearing on the composite panels used on the interior body of business jets after aging. The main objective was to identify and quantify phenomena causing the defects on the interior panels of business planes. This research project is the first part of a project sponsored by CRIAQ and NSERC. The interaction of several materials can lead to various phenomena causing the apparition of surface defects. The project was thus divided into three parts in order to study an increasingly complex problem. the first study deals with the characterization of the different constitutive materials taken separately. This first part focused on thermal, rheological and mechanical aspects of epoxy adhesives. It was shown that the two adhesives used have different mechanical properties and cure kinetic reactions. In addition, the mechanical properties of sandwich composites panels were studied. The second study focused on the analysis of hygrothermal influence on the adhesive and the composite sandwich panels taken separately. Humidity and temperature can have an important effect on the constitutive materials, it is therefore important to know their influence. Finally, the third part deals with the influence of hygrothermal aging on a structure combining all the different materials. Sample panels including fixing zones (insert and resin) were made at the industrial partner's facility according to the industrial procedure. Subsequently, the samples have undergone an accelerated aging. By using deflectometry system, changes in local curvatures with respect to the aging conditions were observed. A correlation between the material characterization results, the aging effects and the surface defect gravity was performed to evaluate the sources and the occurrence of defects. Recommendations have also been made to ensure the project continuity. This project, carried out in an industrial context with the collaboration of Centre de Recherche Industrielle du Quebec ( CRIQ), 3M Canada and the Chaire de recherche sur les composites hautes performances (CCHP) of the department of mechanical engineering of Ecole Polytechnique de Montreal, highlights the importance of the choice of methods and materials in the manufacturing of composite structures.

Evaluation of Ultra High Molecular Weight (UHMW) Polyethylene Panels for Aircraft Arresting Systems

DTIC Science & Technology

2009-08-01

cables. When concrete or asphalt is used directly under the cables, the pavement surface becomes heavily damaged during a short period of time...the sealant and panels, and improving the performance of the asphalt and concrete mixtures adjacent to the panels. DISCLAIMER: The contents of...panels on Runway 34 at Elmendorf AFB.....................22 Figure 25. Some damage to the asphalt mixture adjacent to the concrete strip on Runway 34

A method for the dynamic and thermal stress analysis of space shuttle surface insulation

NASA Technical Reports Server (NTRS)

Ojalvo, I. U.; Levy, A.; Austin, F.

1975-01-01

The thermal protection system of the space shuttle consists of thousands of separate insulation tiles bonded to the orbiter's surface through a soft strain-isolation layer. The individual tiles are relatively thick and possess nonuniform properties. Therefore, each is idealized by finite-element assemblages containing up to 2500 degrees of freedom. Since the tiles affixed to a given structural panel will, in general, interact with one another, application of the standard direct-stiffness method would require equation systems involving excessive numbers of unknowns. This paper presents a method which overcomes this problem through an efficient iterative procedure which requires treatment of only a single tile at any given time. Results of associated static, dynamic, and thermal stress analyses and sufficient conditions for convergence of the iterative solution method are given.

Solar shutter arrangement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fulkerson, P.L.

1988-02-02

In a structure having a roof with a skylight including a glass panel which transmits solar energy, a shutter arrangement supported on the roof is described comprising an insulative flat one-piece solid shutter in the form of a panel selectively and linearly slidable on tracks which conceal the side edges thereof from a position blocking transmittal of solar energy through the glass panel of the skylight into an area within the structure to a position permitting transmittal of solar energy through the glass panel of the skylight into the area within the structure. The skylight presents a space between themore » glass panel and the selectively and linearly slidable insulative flat one-piece solid shutter, where the latter serves as the selective inner wall of the space contiguous with the area within the structure and the glass panel serves as the fixed outer wall of the space, where temperature responsive means is disposed within the space and in direct engagement with the inner surface of the glass panel, where the temperature responsive means is a black thermocouple operating a motor in a driving relationship with the insulative flat one-piece solid shutter. The insulative flat one-piece solid shutter is supported by a cable secured to a rotatable shaft controlled by the motor, where bi-directional movement of the rotatable shaft achieves raising and lowering of the insulative flat one-piece solid shutter to each of the solar energy blocking and transmittal positions, and where the insulative flat one-piece solid shutter includes a reflective surface facing the skylight and a decorative surface facing the area within the structure.« less

Single-strain-gage force/stiffness buckling prediction techniques on a hat-stiffened panel

NASA Technical Reports Server (NTRS)

Hudson, Larry D.; Thompson, Randolph C.

1991-01-01

Predicting the buckling characteristics of a test panel is necessary to ensure panel integrity during a test program. A single-strain-gage buckling prediction method was developed on a hat-stiffened, monolithic titanium buckling panel. The method is an adaptation of the original force/stiffness method which requires back-to-back gages. The single-gage method was developed because the test panel did not have back-to-back gages. The method was used to predict buckling loads and temperatures under various heating and loading conditions. The results correlated well with a finite element buckling analysis. The single-gage force/stiffness method was a valid real-time and post-test buckling prediction technique.

Retrieval of reflections from ambient noise using illumination diagnosis

NASA Astrophysics Data System (ADS)

Vidal, C. Almagro; Draganov, D.; van der Neut, J.; Drijkoningen, G.; Wapenaar, K.

2014-09-01

Seismic interferometry (SI) enables the retrieval of virtual sources at the location of receivers. In the case of passive SI, no active sources are used for the retrieval of the reflection response of the subsurface, but ambient-noise recordings only. The resulting retrieved response is determined by the illumination characteristics of the recorded ambient noise. Characteristics like geometrical distribution and signature of the noise sources, together with the complexity of the medium and the length of the noise records, determine the quality of the retrieved virtual-shot events. To retrieve body wave reflections, one needs to correlate body-wave noise. A source of such noise might be regional seismicity. In regions with notable human presence, the dominant noise sources are generally located at or close to the surface. In the latter case, the noise will be dominated by surface waves and consequently also the retrieved virtual common-source panels will contain dominant retrieved surface waves, drowning out possible retrieved reflections. In order to retrieve reflection events, suppression of the surface waves becomes the most important pre-processing goal. Because of the reasons mentioned above, we propose a fast method to evaluate the illumination characteristics of ambient noise using the correlation results from ambient-noise records. The method is based on the analysis of the so-called source function of the retrieved virtual-shot panel, and evaluates the apparent slowness of arrivals in the correlation results that pass through the position of the virtual source and at zero time. The results of the diagnosis are used to suppress the retrieval of surface waves and therefore to improve the quality of the retrieved reflection response. We explain the approach using modelled data from transient and continuous noise sources and an example from a passive field data set recorded at Annerveen, Northern Netherlands.

An efficient user-oriented method for calculating compressible flow in an about three-dimensional inlets. [panel method

NASA Technical Reports Server (NTRS)

Hess, J. L.; Mack, D. P.; Stockman, N. O.

1979-01-01

A panel method is used to calculate incompressible flow about arbitrary three-dimensional inlets with or without centerbodies for four fundamental flow conditions: unit onset flows parallel to each of the coordinate axes plus static operation. The computing time is scarcely longer than for a single solution. A linear superposition of these solutions quite rigorously gives incompressible flow about the inlet for any angle of attack, angle of yaw, and mass flow rate. Compressibility is accounted for by applying a well-proven correction to the incompressible flow. Since the computing times for the combination and the compressibility correction are small, flows at a large number of inlet operating conditions are obtained rather cheaply. Geometric input is aided by an automatic generating program. A number of graphical output features are provided to aid the user, including surface streamline tracing and automatic generation of curves of curves of constant pressure, Mach number, and flow inclination at selected inlet cross sections. The inlet method and use of the program are described. Illustrative results are presented.

Aerothermal and aeroelastic response prediction of aerospace structures in high-speed flows using direct numerical simulation

NASA Astrophysics Data System (ADS)

Ostoich, Christopher Mark

Future high-speed air vehicles will be lightweight, flexible, and reusable. Ve- hicles fitting this description are subject to severe thermal and fluid dynamic loading from multiple sources such as aerothermal heating, propulsion sys- tem exhaust, and high dynamic pressures. The combination of low-margin design requirements and extreme environmental conditions emphasizes the occurrence of fluid-thermal-structural coupling. Numerous attempts to field such vehicles have been unsuccessful over the past half-century due par- tially to the inability of traditional design and analysis practices to predict the structural response in this flight regime. In this thesis, a high-fidelity computational approach is used to examine the fluid-structural response of aerospace structures in high-speed flows. The method is applied to two cases: one involving a fluid-thermal interaction problem in a hypersonic flow and the other a fluid-structure interaction study involving a turbulent boundary layer and a compliant panel. The coupled fluid-thermal investigation features a nominally rigid alu- minum spherical dome fixed to a ceramic panel holder placed in a Mach 6.59 laminar boundary layer. The problem was originally studied by Glass and Hunt in a 1988 wind tunnel experiment in the NASA Langley 8-Foot High Temperature Tunnel and is motivated by thermally bowed body panels designed for the National Aerospace Plane. In this work, the compressible Navier-Stokes equations for a thermally perfect gas and the transient heat equation in the structure are solved simultaneously using two high-fidelity solvers coupled at the solid-fluid interface. Predicted surface heat fluxes are within 10% of the measured values in the dome interior with greater differ- ences found near the dome edges where uncertainties concerning the exper- imental model's construction likely influence the thermal dynamics. On the flat panel holder, the local surface heat fluxes approach those on the wind- ward dome face due to a dome-induced horseshoe vortex scouring the panel's surface. Comparisons with reduced-order models of heat transfer indicate that they perform with varying levels of accuracy around some portions of the geometry while completely failing to predict significant heat loads in re- gions where the dome-influenced flow impacts the ceramic panel. Cumulative effects of flow-thermal coupling at later simulation times on the reduction of panel drag and surface heat transfer are quantified. The second fluid-structure study investigates the interaction between a thin metallic panel and a Mach 2.25 turbulent boundary layer with an ini- tial momentum thickness Reynolds number of 1200. A transient, non-linear, large deformation, 3D finite element solver is developed to compute the dynamic response of the panel. The solver is coupled at the fluid-structure interface with the compressible Navier-Stokes solver, the latter of which is used for a direct numerical simulation of the turbulent boundary layer. In this approach, no simplifying assumptions regarding the structural solution or turbulence modeling are made in order to get detailed solution data. It is found that the thin panel state evolves into a flutter type response char- acterized by high-amplitude, high-frequency oscillations into the flow. The oscillating panel disturbs the supersonic flow by introducing compression waves, modifying the turbulence, and generating fluctuations in the power exiting the top of the flow domain. The work in this thesis serves as a step forward in structural response prediction in high-speed flows. The results demonstrate the ability of high- fidelity numerical approaches to serve as a guide for reduced-order model improvement and as well as provide accurate and detailed solution data in scenarios where experimental approaches are difficult or impossible.

Improving diaper design to address incontinence associated dermatitis

PubMed Central

2010-01-01

Background Incontinence associated dermatitis (IAD) is an inflammatory skin disease mainly triggered by prolonged skin contact with urine, feces but also liberal detergent use when cleansing the skin. To minimize the epidermal barrier challenge we optimized the design of adult incontinence briefs. In the fluid absorption area we interposed a special type of acidic, curled-type of cellulose between the top sheet in contact with the skin and the absorption core beneath containing the polyacrylate superabsorber. The intention was to minimize disturbance of the already weak acid mantle of aged skin. We also employed air-permeable side panels to minimize skin occlusion and swelling of the stratum corneum. Methods The surface pH of diapers was measured after repeated wetting with a urine substitute fluid at the level of the top sheet. Occlusive effects and hydration of the stratum corneum were measured after a 4 hour application of different side panel materials by corneometry on human volunteers. Finally, we evaluated skin symptoms in 12 patients with preexisting IAD for 21 days following the institutional switch to the optimized diaper design. Local skin care protocols remained in place unchanged. Results The improved design created a surface pH of 4.6 which was stable even after repeated wetting throughout a 5 hour period. The "standard design" briefs had values of 7.1, which is alkaline compared to the acidic surface of normal skin. Side panels made from non-woven material with an air-permeability of more than 1200 l/m2/s avoided excessive hydration of the stratum corneum when compared to the commonly employed air-impermeable plastic films. Resolution of pre-existing IAD skin lesions was noted in 8 out of 12 patients after the switch to the optimized brief design. Conclusions An improved design of adult-type briefs can create an acidic pH on the surface and breathable side panels avoid over-hydration of the stratum corneum and occlusion. This may support the epidermal barrier function and may help to reduce the occurrence of IAD. PMID:21092161

Hybrid Magnetic Shielding

NASA Astrophysics Data System (ADS)

Royal, Kevin; Crawford, Christopher; Mullins, Andrew; Porter, Greg; Blanton, Hunter; Johnstone, Connor; Kistler, Ben; Olivera, Daniela

2017-09-01

The search for the electric dipole moment of the neutron requires the ambient magnetic field to be on the pT scale which is accomplished with large magnetic shielding rooms. These rooms are fitted with large mu-metal sheets to allow for passive cancellation of background magnetic fields. Active shielding technology cannot uniformly cancel background magnetic fields. These issues can be remedied by combining the methods into a hybrid system. The design used is composed of panels that have an active layer of cancellation between two sheets of mu-metal. The panels form a cube and draw in magnetic fields perpendicular to the surface which can then be reduced using active shielding. This work is supported by the Department of Energy under Contract DE-SC0008107.

Optical residual stress measurement in TFT-LCD panels

NASA Astrophysics Data System (ADS)

Wang, Wei-Chung; Sung, Po-Chi

2017-06-01

The residual stress of the glass substrate might be one of causes to produce the non-uniform light distribution defect, i.e. Mura, in thin film transistor-liquid crystal display (TFT-LCD) panels. Glass is a birefringent material with very low birefringence. Furthermore, the thinner and thinner thickness request from the market makes the traditional photoelasticity almost impossible to measure the residual stresses produced in thin glass plates. Recently, a low-level stress measurement method called transmissivity extremities theory of photoelasticity (TEToP) was successfully developed to measure the residual stress in glass plate. Besides, to measure the stress of the glass plate in the TFT-LCD panel whose rear surface may has different kinds of coatings, an advanced reflection photoelasticity was also developed. In this paper, three commercially available glass plates with 0.33mm nominal thickness and three glass circular disks with different coatings were inspected to verify the feasibility of the TEToP and the advanced reflection photoelasticity, respectively.

Fabrication and Testing of Carbon Fiber, Graphite-Epoxy Panels for Submillimeter Telescope Use

NASA Astrophysics Data System (ADS)

Rieger, H.; Helwig, G.; Parks, R. E.; Ulich, B. L.

1983-12-01

An experimental carbon-fiber, graphite-epoxy, aluminum Flexcore sandwich panel roughly 1-m square was made by Dornier System, Friedrichshafen, West Germany. The panel was a pre-prototype of the panels to be used in the dish of the 10-m diameter Sub-Millimeter Telescope, a joint project of the Max-Planck-Institute fur Radioastronomie, Bonn, West Germany, and Steward Observatory, the University of Arizona in Tucson. This paper outlines the fabrication process for the panel and indicates the surface accuracy of the panel replication process. To predict the behavior of the panel under various environmental loads, the panel was modeled structurally using anisotropic elements for the core material. Results of this analysis along with experimental verification of these predictions are also given.

Residual Silicone Detection. [external tank and solid rocket booster surfaces

NASA Technical Reports Server (NTRS)

Smith, T.

1980-01-01

Both photoelectron emission and ellipsometry proved successful in detecting silicone contamination on unpainted and epoxy painted metal surfaces such as those of the external tank and the solid rocket booster. Great success was achieved using photoelectron emission (PEE). Panels were deliberately contaminated to controlled levels and then mapped with PEE to reveal the areas and levels that were contaminated. The panels were then tested with regard to adhesive properties. Tapes were bonded over the contaminated and uncontaminated regions and the peel force was measured, or the contaminated panels were bonded (with CPR 483 foam) to uncontaminated panels and made into lap shear specimens. Other panels were bonded and made into wedge specimens for hydrothermal stress endurance tests. Strong adhesion resulted if the PEE signal fell within an acceptance window, but was poor outside the acceptance window. A prototype instrument is being prepared which can automatically be scanned over the external liquid hydrogen tank and identify those regions that are contaminated and will cause bond degradation.

Analysis of AC and DC Lighting Systems with 150-Watt Peak Solar Panel in Denpasar Based on NASA Data

NASA Astrophysics Data System (ADS)

Narottama, A. A. N. M.; Amerta Yasa, K.; Suwardana, I. W.; Sapteka, A. A. N. G.; Priambodo, P. S.

2018-01-01

Solar energy on the Earth’s surface has different magnitudes on every longitude and latitude. National Aeronautics and Space Administration (NASA) provides surface meteorology and solar energy database which can be accessed openly online. This database delivers information about Monthly Averaged Insolation Incident On A Horizontal Surface, Monthly Averaged Insolation Incident On A Horizontal Surface At Indicated GMT Times and also data about Equivalent Number Of No-Sun Or Black Days for any latitude and longitude. Therefore, we investigate the lighting systems with 150-Watt peak solar panel in Denpasar City, the capital province of Bali. Based on NASA data, we analyse the received wattage by a unit of 150-Watt peak solar panel in Denpasar City and the sustainability of 150-Watt peak solar panel to supply energy for 432-Watt hour/day AC and 360-Watt hour/day DC lighting systems using 1.2 kWh battery. The result shows that the maximum received wattage by a unit of 150-Watt peak solar panel is 0.76 kW/day in October. We concluded that the 1.2 kWh installed battery has higher capacity than the battery capacity needed in March, the month with highest no-sun days, for both AC and DC lighting systems. We calculate that the installed battery can be used to store the sustainable energy from sun needed by AC and DC lighting system for about 2.78 days and 3.51 days, consecutively.

Cryogenic performance of slotted brazed Rene 41 honeycomb panels

NASA Technical Reports Server (NTRS)

Hepler, A. K.; Swegle, A. R.

1982-01-01

Two brazed Rene 41 honeycomb panels that would incorporate a frame element were designed, fabricated and tested. The panels were representative of the lower surface of an advanced space transportation vehicle. The first panel was a two span panel supported by a center frame and on edges parallel to it. The second panel was a two span panel supported by a center frame and on edges parallel to it. The second panel was a three span panel supported on two frames and on edges parallel to the frames. Each panel had its outer skin slotted to reduce the thermal stresses of the panel skins. The first panel was tested under simulated boost conditions that included liquid hydrogen exposure of the frame and inner skin and radiant heat to 478K on the outer skins. The first panel was tested to investigate the effect of thermal stresses in skins and core caused by the panel being restrained by a cold integral frame and to observe the effects of frost formation and possible liquid air development in and around outer skin slots.

Modeling of Sensor Placement Strategy for Shape Sensing and Structural Health Monitoring of a Wing-Shaped Sandwich Panel Using Inverse Finite Element Method.

PubMed

Kefal, Adnan; Yildiz, Mehmet

2017-11-30

This paper investigated the effect of sensor density and alignment for three-dimensional shape sensing of an airplane-wing-shaped thick panel subjected to three different loading conditions, i.e., bending, torsion, and membrane loads. For shape sensing analysis of the panel, the Inverse Finite Element Method (iFEM) was used together with the Refined Zigzag Theory (RZT), in order to enable accurate predictions for transverse deflection and through-the-thickness variation of interfacial displacements. In this study, the iFEM-RZT algorithm is implemented by utilizing a novel three-node C°-continuous inverse-shell element, known as i3-RZT. The discrete strain data is generated numerically through performing a high-fidelity finite element analysis on the wing-shaped panel. This numerical strain data represents experimental strain readings obtained from surface patched strain gauges or embedded fiber Bragg grating (FBG) sensors. Three different sensor placement configurations with varying density and alignment of strain data were examined and their corresponding displacement contours were compared with those of reference solutions. The results indicate that a sparse distribution of FBG sensors (uniaxial strain measurements), aligned in only the longitudinal direction, is sufficient for predicting accurate full-field membrane and bending responses (deformed shapes) of the panel, including a true zigzag representation of interfacial displacements. On the other hand, a sparse deployment of strain rosettes (triaxial strain measurements) is essentially enough to produce torsion shapes that are as accurate as those of predicted by a dense sensor placement configuration. Hence, the potential applicability and practical aspects of i3-RZT/iFEM methodology is proven for three-dimensional shape-sensing of future aerospace structures.

Nano and Microparticle-Enhanced Immunosensor Approaches for the Detection of Cancer Biomarker Proteins

NASA Astrophysics Data System (ADS)

Mani, Vigneshwaran

Accurate, sensitive, point-of-care multiplexed protein measurements are critical for early disease detection and monitoring, impacting biomarker and drug discovery, and personalized medicine. Significant application involves monitoring panels of proteins in the blood that are biomarkers for diagnosing cancer. However, measurements of biomarker panels in blood or other bodily fluids have been slow to integrate into current practice of cancer diagnostics partly due to the lack of technically simple, low-cost, sensitive, point-of-care multiplexed measurement devices, as well as the lack of rigorously validated protein panels. The present thesis in part addresses these limitations by the development of electrochemical and surface plasmon resonance (SPR) immunosensors utilizing 1mum superparamagnetic labels for accurate detection of prostate cancer biomarker proteins in patient serum samples. Electrochemical discrete immunosensors featuring nanostructured surface with densely packed 5 nm glutathione-coated gold nanoparticles coupled with multi-enzyme magnetic particle (MP) labels enabled measurement of prostate specific antigen (PSA) with a detection limit (DL) of 0.5 pg mL-1 in undiluted serum. Such low DLs are attributed to high surface area, conductivity of nanostructured surface, and multi-enzyme signal amplification. DLs are further improved by utilizing MP bioconjugated with more than 100,000 antibody labels to offline capture proteins from the serum sample matrix, minimizing nonspecific binding of interfering proteins on sensor surface before detection. This approach provided an unprecedented 10 fg DL mL-1 for PSA in undiluted serum using a flow SPR biosensor. Finally electrochemical microfluidic immunoarrays featuring nanostructured surface and offline protein capture by multi-label MPs enabled multiplexed detection of prostate cancer biomarkers PSA and interleukin-6 (IL-6). These approaches provided up to 1000-fold lower DLs compared to commercial bead based assays. The high sensitivity of these approaches will allow monitoring of biomarker levels in diseases states where proteins are in sub pg mL -1 concentrations that are normally challenging to detect using traditional methods such as enzyme linked immunosorbent assays (ELISA). Further emphases will be on SPR-based fundamental studies on binding affinity enhancement of MP conjugates to protein surfaces. In addition, this thesis describes the assembly of glucose/O2 enzymatic biofuel cells for power generation utilizing layer-by-layer films of osmium redox polymers and enzymes. Towards the end, the present thesis describes a simple, low-cost and accurate paper-based electrochemical device fabrication methods and its applications towards monitoring genotoxic activities in the environmental samples.

Description of Panel Method Code ANTARES

NASA Technical Reports Server (NTRS)

Ulbrich, Norbert; George, Mike (Technical Monitor)

2000-01-01

Panel method code ANTARES was developed to compute wall interference corrections in a rectangular wind tunnel. The code uses point doublets to represent blockage effects and line doublets to represent lifting effects of a wind tunnel model. Subsonic compressibility effects are modeled by applying the Prandtl-Glauert transformation. The closed wall, open jet, or perforated wall boundary condition may be assigned to a wall panel centroid. The tunnel walls can be represented by using up to 8000 panels. The accuracy of panel method code ANTARES was successfully investigated by comparing solutions for the closed wall and open jet boundary condition with corresponding Method of Images solutions. Fourier transform solutions of a two-dimensional wind tunnel flow field were used to check the application of the perforated wall boundary condition. Studies showed that the accuracy of panel method code ANTARES can be improved by increasing the total number of wall panels in the circumferential direction. It was also shown that the accuracy decreases with increasing free-stream Mach number of the wind tunnel flow field.

The development of composite materials for spacecraft precision reflector panels

NASA Technical Reports Server (NTRS)

Tompkins, Stephen S.; Bowles, David E.; Funk, Joan G.; Towell, Timothy W.; Lavoie, J. A.

1990-01-01

One of the critical technology needs for large precision reflectors required for future astrophysics and optical communications is in the area of structural materials. Therefore, a major area of the Precision Segmented Reflector Program at NASA is to develop lightweight composite reflector panels with durable, space environmentally stable materials which maintain both surface figure and required surface accuracy necessary for space telescope applications. Results from the materials research and development program at NASA Langley Research Center are discussed. Advanced materials that meet the reflector panel requirements are identified. Thermal, mechanical and durability properties of candidate materials after exposure to simulated space environments are compared to the baseline material.

Evaluation of three thermal protection systems in a hypersonic high-heating-rate environment induced by an elevon deflected 30 deg

NASA Technical Reports Server (NTRS)

Taylor, A. H.; Jackson, L. R.; Weinstein, I.

1977-01-01

Three thermal protection systems proposed for a hypersonic research airplane were subjected to high heating rates in the Langley 8 foot, high temperature structures tunnel. Metallic heat sink (Lockalloy), reusable surface insulation, and insulator-ablator materials were each tested under similar conditions. The specimens were tested for a 10 second exposure on the windward side of an elevon deflected 30 deg. The metallic heat sink panel exhibited no damage; whereas the reusable surface insulation tiles were debonded from the panel and the insulator-ablator panel eroded through its thickness, thus exposing the aluminum structure to the Mach 7 environment.

The Effect of Boundary Support and Reflector Dimensions on Inflatable Parabolic Antenna Performance

NASA Technical Reports Server (NTRS)

Coleman, Michael J.; Baginski, Frank; Romanofsky, Robert R.

2011-01-01

For parabolic antennas with sufficient surface accuracy, more power can be radiated with a larger aperture size. This paper explores the performance of antennas of various size and reflector depth. The particular focus is on a large inflatable elastic antenna reflector that is supported about its perimeter by a set of elastic tendons and is subjected to a constant hydrostatic pressure. The surface accuracy of the antenna is measured by an RMS calculation, while the reflector phase error component of the efficiency is determined by computing the power density at boresight. In the analysis, the calculation of antenna efficiency is not based on the Ruze Equation. Hence, no assumption regarding the distribution of the reflector surface distortions is presumed. The reflector surface is modeled as an isotropic elastic membrane using a linear stress-strain constitutive relation. Three types of antenna reflector construction are considered: one molded to an ideal parabolic form and two different flat panel design patterns. The flat panel surfaces are constructed by seaming together panels in a manner that the desired parabolic shape is approximately attained after pressurization. Numerical solutions of the model problem are calculated under a variety of conditions in order to estimate the accuracy and efficiency of these antenna systems. In the case of the flat panel constructions, several different cutting patterns are analyzed in order to determine an optimal cutting strategy.

Numerical optimization techniques for bound circulation distribution for minimum induced drag of Nonplanar wings: Computer program documentation

NASA Technical Reports Server (NTRS)

Kuhlman, J. M.; Ku, T. J.

1981-01-01

A two dimensional advanced panel far-field potential flow model of the undistorted, interacting wakes of multiple lifting surfaces was developed which allows the determination of the spanwise bound circulation distribution required for minimum induced drag. This model was implemented in a FORTRAN computer program, the use of which is documented in this report. The nonplanar wakes are broken up into variable sized, flat panels, as chosen by the user. The wake vortex sheet strength is assumed to vary linearly over each of these panels, resulting in a quadratic variation of bound circulation. Panels are infinite in the streamwise direction. The theory is briefly summarized herein; sample results are given for multiple, nonplanar, lifting surfaces, and the use of the computer program is detailed in the appendixes.

Thermal-Structural Evaluation of TD Ni-20Cr Thermal Protection System Panels

NASA Technical Reports Server (NTRS)

Eidinoff, H. L.; Rose, L.

1974-01-01

The results of a thermal-structural test program to verify the performance of a metallic/radiative Thermal Protection System (TPS) under reentry conditions are presented. This TPS panel is suitable for multiple reentry, high L/D space vehicles, such as the NASA space shuttle, having surface temperatures up to 1200 C (2200 F). The TPS panel tested consists of a corrugation-stiffened, beaded-skin TD Ni-20Cr metallic heat shield backed by a flexible fibrous quartz and radiative shield insulative system. Test conditions simulated the critical heating and aerodynamic pressure environments expected during 100 repeated missions of a reentry vehicle. Temperatures were measured during each reentry cycle; heat-shield flatness surveys to measure permanent set of the metallic components were made every 10 cycles. The TPS panel, in spite of localized surface failures, performed its designated function.

The DoE method as an efficient tool for modeling the behavior of monocrystalline Si-PV module

NASA Astrophysics Data System (ADS)

Kessaissia, Fatma Zohra; Zegaoui, Abdallah; Boutoubat, Mohamed; Allouache, Hadj; Aillerie, Michel; Charles, Jean-Pierre

2018-05-01

The objective of this paper is to apply the Design of Experiments (DoE) method to study and to obtain a predictive model of any marketed monocrystalline photovoltaic (mc-PV) module. This technique allows us to have a mathematical model that represents the predicted responses depending upon input factors and experimental data. Therefore, the DoE model for characterization and modeling of mc-PV module behavior can be obtained by just performing a set of experimental trials. The DoE model of the mc-PV panel evaluates the predictive maximum power, as a function of irradiation and temperature in a bounded domain of study for inputs. For the mc-PV panel, the predictive model for both one level and two levels were developed taking into account both influences of the main effect and the interactive effects on the considered factors. The DoE method is then implemented by developing a code under Matlab software. The code allows us to simulate, characterize, and validate the predictive model of the mc-PV panel. The calculated results were compared to the experimental data, errors were estimated, and an accurate validation of the predictive models was evaluated by the surface response. Finally, we conclude that the predictive models reproduce the experimental trials and are defined within a good accuracy.

F-16XL Wing Pressure Distributions and Shock Fence Results from Mach 1.4 to Mach 2.0

NASA Technical Reports Server (NTRS)

Landers, Stephen F.; Saltzman, John A.; Bjarke, Lisa J.

1997-01-01

Chordwise pressure distributions were obtained in-flight on the upper and lower surfaces of the F-16XL ship 2 aircraft wing between Mach 1.4 and Mach 2.0. This experiment was conducted to determine the location of shock waves which could compromise or invalidate a follow-on test of a large chord laminar flow control suction panel. On the upper surface, the canopy closure shock crossed an area which would be covered by a proposed laminar flow suction panel. At the laminar flow experiment design Mach number of 1.9, 91 percent of the suction panel area would be forward of the shock. At Mach 1.4, that value reduces to 65 percent. On the lower surface, a shock from the inlet diverter would impinge on the proposed suction panel leading edge. A chordwise plate mounted vertically to deflect shock waves, called a shock fence, was installed between the inlet diverter and the leading edge. This plate was effective in reducing the pressure gradients caused by the inlet shock system.

Thermal Performance of Precast Concrete Sandwich Panel (PCSP) Design for Sustainable Built Environment

NASA Astrophysics Data System (ADS)

Ern, Peniel Ang Soon; Ling, Lim Mei; Kasim, Narimah; Hamid, Zuhairi Abd; Masrom, Md Asrul Nasid Bin

2017-10-01

Malaysia’s awareness of performance criteria in construction industry towards a sustainable built environment with the use of precast concrete sandwich panel (PCSP) system is applied in the building’s wall to study the structural behaviour. However, very limited studies are conducted on the thermal insulation of exterior and interior panels in PCSP design. In hot countries such as Malaysia, proper designs of panel are important to obtain better thermal insulation for building. This study is based on thermal performance of precast concrete sandwich panel design for sustainable built environment in Malaysia. In this research, three full specimens, which are control specimen (C), foamed concrete (FC) panels and concrete panels with added palm oil fuel ash (FC+ POFA), where FC and FC+POFA sandwiched with gypsum board (G) were produced to investigate their thermal performance. Temperature difference of exterior and interior surface of specimen was used as indicators of thermal-insulating performance of PCSP design. Heat transfer test by halogen lamp was carried out on three specimens where the exterior surface of specimens was exposed to the halogen lamp. The temperature reading of exterior and interior surface for three specimens were recorded with the help of thermocouple. Other factors also studied the workability, compressive strength and axial compressive strength of the specimens. This study has shown that FC + POFA specimen has the strength nearer to normal specimen (C + FC specimen). Meanwhile, the heat transfer results show that the FC+POFA has better thermal insulation performance compared to C and FC specimens with the highest temperature difference, 3.4°C compared to other specimens. The results from this research are useful to be implemented in construction due to its benefits such as reduction of energy consumption in air-conditioning, reduction of construction periods and eco-friendly materials.

Surface properties-vehicle interaction

NASA Astrophysics Data System (ADS)

Huft, D. L.; Her, I.; Agrawal, S. K.; Zimmer, R. A.; Bester, C. J.

Several topics related to the surface properties of aircraft runways are discussed. The South Dakota profilometer; development of a data acquisition method for noncontact pavement macrotexture measurement; the traction of an aircraft tire on grooved and porous asphaltic concrete; holes in the pavements; the effect of pavement type and condition on the fuel consumption of vehicles; the traction loss of a suspended tire on a sinusoidal road; the effect of vehicle and driver characteristics on the psychological evaluation of road roughness; the correlation of subjective panel ratings of pavement ride quality with profilometer-derived measures of pavement roughness; a microprocessor-based noncontact distance measuring control system, and, the representation of pavement surface topography in predicting runoff depths and hydroplaning potential are discussed.

Determination of the Fracture Parameters in a Stiffened Composite Panel

NASA Technical Reports Server (NTRS)

Lin, Chung-Yi

2000-01-01

A modified J-integral, namely the equivalent domain integral, is derived for a three-dimensional anisotropic cracked solid to evaluate the stress intensity factor along the crack front using the finite element method. Based on the equivalent domain integral method with auxiliary fields, an interaction integral is also derived to extract the second fracture parameter, the T-stress, from the finite element results. The auxiliary fields are the two-dimensional plane strain solutions of monoclinic materials with the plane of symmetry at x(sub 3) = 0 under point loads applied at the crack tip. These solutions are expressed in a compact form based on the Stroh formalism. Both integrals can be implemented into a single numerical procedure to determine the distributions of stress intensity factor and T-stress components, T11, T13, and thus T33, along a three-dimensional crack front. The effects of plate thickness and crack length on the variation of the stress intensity factor and T-stresses through the thickness are investigated in detail for through-thickness center-cracked plates (isotropic and orthotropic) and orthotropic stiffened panels under pure mode-I loading conditions. For all the cases studied, T11 remains negative. For plates with the same dimensions, a larger size of crack yields larger magnitude of the normalized stress intensity factor and normalized T-stresses. The results in orthotropic stiffened panels exhibit an opposite trend in general. As expected, for the thicker panels, the fracture parameters evaluated through the thickness, except the region near the free surfaces, approach two-dimensional plane strain solutions. In summary, the numerical methods presented in this research demonstrate their high computational effectiveness and good numerical accuracy in extracting these fracture parameters from the finite element results in three-dimensional cracked solids.

Low-cost fabrication and direct bond installation of flat, single-curvature and compound-curvature ablative heat shield panels

NASA Technical Reports Server (NTRS)

Norwood, L. B.

1972-01-01

Procedures for low cost fabrication and direct bond installation of flat, single curved, and compound curvature ablative heat shields on a DC-3 aircraft are discussed. The panel sizes and attachment locations are identified. In addition to the bonding of the four contoured panels, two flat panels were bonded to the nearly flat, lower surface of the center wing section. The detailed requirements and objectives of the investigation are described.

Method of improving field emission characteristics of diamond thin films

DOEpatents

Krauss, A.R.; Gruen, D.M.

1999-05-11

A method of preparing diamond thin films with improved field emission properties is disclosed. The method includes preparing a diamond thin film on a substrate, such as Mo, W, Si and Ni. An atmosphere of hydrogen (molecular or atomic) can be provided above the already deposited film to form absorbed hydrogen to reduce the work function and enhance field emission properties of the diamond film. In addition, hydrogen can be absorbed on intergranular surfaces to enhance electrical conductivity of the diamond film. The treated diamond film can be part of a microtip array in a flat panel display. 3 figs.

Method of improving field emission characteristics of diamond thin films

DOEpatents

Krauss, Alan R.; Gruen, Dieter M.

1999-01-01

A method of preparing diamond thin films with improved field emission properties. The method includes preparing a diamond thin film on a substrate, such as Mo, W, Si and Ni. An atmosphere of hydrogen (molecular or atomic) can be provided above the already deposited film to form absorbed hydrogen to reduce the work function and enhance field emission properties of the diamond film. In addition, hydrogen can be absorbed on intergranular surfaces to enhance electrical conductivity of the diamond film. The treated diamond film can be part of a microtip array in a flat panel display.

Bonded and Stitched Composite Structure

NASA Technical Reports Server (NTRS)

Zalewski, Bart F. (Inventor); Dial, William B. (Inventor)

2014-01-01

A method of forming a composite structure can include providing a plurality of composite panels of material, each composite panel having a plurality of holes extending through the panel. An adhesive layer is applied to each composite panel and a adjoining layer is applied over the adhesive layer. The method also includes stitching the composite panels, adhesive layer, and adjoining layer together by passing a length of a flexible connecting element into the plurality of holes in the composite panels of material. At least the adhesive layer is cured to bond the composite panels together and thereby form the composite structure.

Coordinate metrology of a primary surface composite panel from the Large Millimeter Telescope

NASA Astrophysics Data System (ADS)

Gale, David M.; Lucero Álvarez, Maribel; Cabrera Cuevas, Lizeth; Leon-Huerta, Andrea; Arizmendi Reyes, Edgar; Icasio Hernández, Octavio; Castro Santos, David; Hernández Ríos, Emilio; Tecuapetla Sosa, Esteban; Tzile Torres, Carlos; Viliesid Alonso, Miguel

2016-07-01

The Large Millimeter Telescope (LMT) is a single-dish fully-steerable radio telescope presently operating with a 32.5 m parabolic primary reflector, in the process of extension to 50 m. The project is managed by the Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE) in México, and the University of Massachusetts Amherst, USA. A laminated surface panel from the LMT primary reflector has been subjected to a surface measurement assay at Mexico's National Metrology Center (CENAM). Data obtained using a coordinate measuring machine and laser tracker owned by CENAM is compared with measurements using an identical model laser tracker and the photogrammetry technique, the latter systems owned and operated by the LMT. All measurements were performed within the controlled metrology environment at CENAM. The measurement exercise is intended to prepare the groundwork for converting this spare surface panel into a calibrated work-piece. The establishment of a calibrated work-piece provides quality assurance for metrology through measurement traceability. It also simplifies the evaluation of measurement uncertainty for coordinate metrology procedures used by the LMT project during reflector surface qualification.

Paradigm Diagnostics Salmonella Indicator Broth (PDX-SIB) for detection of Salmonella on selected environmental surfaces.

PubMed

Olstein, Alan; Griffith, Leena; Feirtag, Joellen; Pearson, Nicole

2013-01-01

The Paradigm Diagnostics Salmonella Indicator Broth (PDX-SIB) is intended as a single-step selective enrichment indicator broth to be used as a simple screening test for the presence of Salmonella spp. in environmental samples. This method permits the end user to avoid multistep sample processing to identify presumptively positive samples, as exemplified by standard U.S. reference methods. PDX-SIB permits the outgrowth of Salmonella while inhibiting the growth of competitive Gram-negative and -positive microflora. Growth of Salmonella-positive cultures results in a visual color change of the medium from purple to yellow when the sample is grown at 37 +/- 1 degree C. Performance of PDX-SIB has been evaluated in five different categories: inclusivity-exclusivity, methods comparison, ruggedness, lot-to-lot variability, and shelf stability. The inclusivity panel included 100 different Salmonella serovars, 98 of which were SIB-positive during the 30 to 48 h incubation period. The exclusivity panel included 33 different non-Salmonella microorganisms, 31 of which were SIB-negative during the incubation period. Methods comparison studies included four different surfaces: S. Newport on plastic, S. Anatum on sealed concrete, S. Abaetetuba on ceramic tile, and S. Typhimurium in the presence of 1 log excess of Citrobacter freundii. Results of the methods comparison studies demonstrated no statistical difference between the SIB method and the U.S. Food and Drug Administration-Bacteriological Analytical Manual reference method, as measured by the Mantel-Haenszel Chi-square test. Ruggedness studies demonstrated little variation in test results when SIB incubation temperatures were varied over a 34-40 degrees C range. Lot-to-lot consistency results suggest no detectable differences in manufactured goods using two reference Salmonella serovars and one non-Salmonella microorganism.

Brushless Cleaning of Solar Panels and Windows

NASA Technical Reports Server (NTRS)

Schneider, H. W.

1982-01-01

Machine proposed for cleaning solar panels and reflectors uses multiple vortexes of air, solvent, and water to remove dust and dirt. Uses no brushes that might abrade solar surfaces and thereby reduce efficiency. Machine can be readily automated and can be used on curved surfaces such as aparbolic reflectors as well as on flat ones. Cleaning fluids are recycled, so that large quantities of water and solvent are not needed.

Coupled Electro-Magneto-Mechanical-Acoustic Analysis Method Developed by Using 2D Finite Element Method for Flat Panel Speaker Driven by Magnetostrictive-Material-Based Actuator

NASA Astrophysics Data System (ADS)

Yoo, Byungjin; Hirata, Katsuhiro; Oonishi, Atsurou

In this study, a coupled analysis method for flat panel speakers driven by giant magnetostrictive material (GMM) based actuator was developed. The sound field produced by a flat panel speaker that is driven by a GMM actuator depends on the vibration of the flat panel, this vibration is a result of magnetostriction property of the GMM. In this case, to predict the sound pressure level (SPL) in the audio-frequency range, it is necessary to take into account not only the magnetostriction property of the GMM but also the effect of eddy current and the vibration characteristics of the actuator and the flat panel. In this paper, a coupled electromagnetic-structural-acoustic analysis method is presented; this method was developed by using the finite element method (FEM). This analysis method is used to predict the performance of a flat panel speaker in the audio-frequency range. The validity of the analysis method is verified by comparing with the measurement results of a prototype speaker.

An optimal design of wind turbine and ship structure based on neuro-response surface method

NASA Astrophysics Data System (ADS)

Lee, Jae-Chul; Shin, Sung-Chul; Kim, Soo-Young

2015-07-01

The geometry of engineering systems affects their performances. For this reason, the shape of engineering systems needs to be optimized in the initial design stage. However, engineering system design problems consist of multi-objective optimization and the performance analysis using commercial code or numerical analysis is generally time-consuming. To solve these problems, many engineers perform the optimization using the approximation model (response surface). The Response Surface Method (RSM) is generally used to predict the system performance in engineering research field, but RSM presents some prediction errors for highly nonlinear systems. The major objective of this research is to establish an optimal design method for multi-objective problems and confirm its applicability. The proposed process is composed of three parts: definition of geometry, generation of response surface, and optimization process. To reduce the time for performance analysis and minimize the prediction errors, the approximation model is generated using the Backpropagation Artificial Neural Network (BPANN) which is considered as Neuro-Response Surface Method (NRSM). The optimization is done for the generated response surface by non-dominated sorting genetic algorithm-II (NSGA-II). Through case studies of marine system and ship structure (substructure of floating offshore wind turbine considering hydrodynamics performances and bulk carrier bottom stiffened panels considering structure performance), we have confirmed the applicability of the proposed method for multi-objective side constraint optimization problems.

The development of a closed-loop flight controller with panel method integration for gust alleviation using biomimetic feathers on aircraft wings

NASA Astrophysics Data System (ADS)

Blower, Christopher J.; Lee, Woody; Wickenheiser, Adam M.

2012-04-01

This paper presents the development of a biomimetic closed-loop flight controller that integrates gust alleviation and flight control into a single distributed system. Modern flight controllers predominantly rely on and respond to perturbations in the global states, resulting in rotation or displacement of the entire aircraft prior to the response. This bio-inspired gust alleviation system (GAS) employs active deflection of electromechanical feathers that react to changes in the airflow, i.e. the local states. The GAS design is a skeletal wing structure with a network of featherlike panels installed on the wing's surfaces, creating the airfoil profile and replacing the trailing-edge flaps. In this study, a dynamic model of the GAS-integrated wing is simulated to compute gust-induced disturbances. The system implements continuous adjustment to flap orientation to perform corrective responses to inbound gusts. MATLAB simulations, using a closed-loop LQR integrated with a 2D adaptive panel method, allow analysis of the morphing structure's aerodynamic data. Non-linear and linear dynamic models of the GAS are compared to a traditional single control surface baseline wing. The feedback loops synthesized rely on inertial changes in the global states; however, variations in number and location of feather actuation are compared. The bio-inspired system's distributed control effort allows the flight controller to interchange between the single and dual trailing edge flap profiles, thereby offering an improved efficiency to gust response in comparison to the traditional wing configuration. The introduction of aero-braking during continuous gusting flows offers a 25% reduction in x-velocity deviation; other flight parameters can be reduced in magnitude and deviation through control weighting optimization. Consequently, the GAS demonstrates enhancements to maneuverability and stability in turbulent intensive environments.

Micro Dot Patterning on the Light Guide Panel Using Powder Blasting.

PubMed

Jang, Ho Su; Cho, Myeong Woo; Park, Dong Sam

2008-02-08

This study is to develop a micromachining technology for a light guidepanel(LGP) mold, whereby micro dot patterns are formed on a LGP surface by a singleinjection process instead of existing screen printing processes. The micro powder blastingtechnique is applied to form micro dot patterns on the LGP mold surface. The optimalconditions for masking, laminating, exposure, and developing processes to form the microdot patterns are first experimentally investigated. A LGP mold with masked micro patternsis then machined using the micro powder blasting method and the machinability of themicro dot patterns is verified. A prototype LGP is test- injected using the developed LGPmold and a shape analysis of the patterns and performance testing of the injected LGP arecarried out. As an additional approach, matte finishing, a special surface treatment method,is applied to the mold surface to improve the light diffusion characteristics, uniformity andbrightness of the LGP. The results of this study show that the applied powder blastingmethod can be successfully used to manufacture LGPs with micro patterns by just singleinjection using the developed mold and thereby replace existing screen printing methods.

A lifting surface computer code with jet-in-crossflow interference effects. Volume 1: Theoretical description

NASA Technical Reports Server (NTRS)

Furlong, K. L.; Fearn, R. L.

1983-01-01

A method is proposed to combine a numerical description of a jet in a crossflow with a lifting surface panel code to calculate the jet/aerodynamic-surface interference effects on a V/STOL aircraft. An iterative technique is suggested that starts with a model for the properties of a jet/flat plate configuration and modifies these properties based on the flow field calculated for the configuration of interest. The method would estimate the pressures, forces, and moments on an aircraft out of ground effect. A first-order approximation to the method suggested is developed and applied to two simple configurations. The first-order approximation is a noniterative precedure which does not allow for interactions between multiple jets in a crossflow and also does not account for the influence of lifting surfaces on the jet properties. The jet/flat plate model utilized in the examples presented is restricted to a uniform round jet injected perpendicularly into a uniform crossflow for a range of jet-to-crossflow velocity ratios from three to ten.

Space and surface power for the space exploration initiative: Results from project outreach

NASA Technical Reports Server (NTRS)

Shipbaugh, C.; Solomon, K.; Gonzales, D.; Juncosa, M.; Bauer, T.; Salter, R.

1991-01-01

The analysis and evaluations of the Space and Surface Power panel, one of eight panels created by RAND to screen and analyze submissions to the Space Exploration Initiative (SEI) Outreach Program, is documented. In addition to managing and evaluating the responses, or submissions, to this public outreach program, RAND conducted its own analysis and evaluation relevent to SEI mission concepts, systems, and technologies. The Power panel screened and analyzed submissions for which a substantial portion of the concepts involved power generation sources, transmission, distribution, thermal management, and handling of power (including conditioning, conversion, packaging, and enhancements in system components). A background discussion of the areas the Power panel covered and the issues the reviewers considered pertinent to the analysis of power submissions are presented. An overview of each of the highest-ranked submissions and then a discussion of these submissions is presented. The results of the analysis is presented.

Supersonic pressure measurements and comparison of theory to experiment for an arrow-wing configuration

NASA Technical Reports Server (NTRS)

Manro, M. E.

1976-01-01

A wind tunnel test of an arrow-wing-body configuration consisting of flat and twisted wings, as well as leading- and trailing-edge control surface deflections, was conducted at Mach numbers from 1.54 to 2.50 to provide an experimental pressure data base for comparison with theoretical methods. Theory-to-experiment comparisons of detailed pressure distributions were made using a state-of-the-art inviscid flow, constant-pressure-panel method. Emphasis was on conditions under which this theory is valid for both flat and twisted wings.

B-ALL minimal residual disease flow cytometry: an application of a novel method for optimization of a single-tube model.

PubMed

Shaver, Aaron C; Greig, Bruce W; Mosse, Claudio A; Seegmiller, Adam C

2015-05-01

Optimizing a clinical flow cytometry panel can be a subjective process dependent on experience. We develop a quantitative method to make this process more rigorous and apply it to B lymphoblastic leukemia/lymphoma (B-ALL) minimal residual disease (MRD) testing. We retrospectively analyzed our existing three-tube, seven-color B-ALL MRD panel and used our novel method to develop an optimized one-tube, eight-color panel, which was tested prospectively. The optimized one-tube, eight-color panel resulted in greater efficiency of time and resources with no loss in diagnostic power. Constructing a flow cytometry panel using a rigorous, objective, quantitative method permits optimization and avoids problems of interdependence and redundancy in a large, multiantigen panel. Copyright© by the American Society for Clinical Pathology.

Composite materials for precision space reflector panels

NASA Technical Reports Server (NTRS)

Tompkins, Stephen S.; Funk, Joan G.; Bowles, David E.; Towell, Timothy W.; Connell, John W.

1992-01-01

One of the critical technology needs of large precision reflectors for future astrophysical and optical communications satellites lies in the area of structural materials. Results from a materials research and development program at NASA Langley Research Center to provide materials for these reflector applications are discussed. Advanced materials that meet the reflector panel requirements are identified, and thermal, mechanical and durability properties of candidate materials after exposure to simulated space environments are compared. A parabolic, graphite-phenolic honeycomb composite panel having a surface accuracy of 70.8 microinches rms and an areal weight of 1.17 lbm/sq ft was fabricated with T50/ERL1962 facesheets, a PAEI thermoplastic surface film, and Al and SiO(x) coatings.

77 FR 8328 - Open Meeting of the Taxpayer Advocacy Panel Face-to-Face Service Methods Project Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-14

... Face-to-Face Service Methods Project Committee AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Notice of meeting. SUMMARY: An open meeting of the Taxpayer Advocacy Panel Face-to-Face Service Methods... Panel Face-to-Face Service Methods Project Committee will be held Tuesday, March 13, 2012, at 2 p.m...

High Density Methane Storage in Nanoporous Carbon

NASA Astrophysics Data System (ADS)

Rash, Tyler; Dohnke, Elmar; Soo, Yuchoong; Maland, Brett; Doynov, Plamen; Lin, Yuyi; Pfeifer, Peter; Mriglobal Collaboration; All-Craft Team

2014-03-01

Development of low-pressure, high-capacity adsorbent based storage technology for natural gas (NG) as fuel for advanced transportation (flat-panel tank for NG vehicles) is necessary in order to address the temperature, pressure, weight, and volume constraints present in conventional storage methods (CNG & LNG.) Subcritical nitrogen adsorption experiments show that our nanoporous carbon hosts extended narrow channels which generate a high surface area and strong Van der Waals forces capable of increasing the density of NG into a high-density fluid. This improvement in storage density over compressed natural gas without an adsorbent occurs at ambient temperature and pressures ranging from 0-260 bar (3600 psi.) The temperature, pressure, and storage capacity of a 40 L flat-panel adsorbed NG tank filled with 20 kg of nanoporous carbon will be featured.

Characterisation of CFRP surface contamination by laser induced fluorescence

NASA Astrophysics Data System (ADS)

Malinowski, Pawel H.; Sawczak, Miroslaw; Wandowski, Tomasz; Ostachowicz, Wieslaw M.; Cenian, Adam

2014-03-01

The application of Carbon Fibre Reinforced Polymers (CFRP) in aeronautics has been increasing. The CFRP elements are joint using rivets and adhesive bonding. The reliability of the bonding limits the use of adhesive bonding for primary aircraft structures, therefore it is important to assess the bond quality. The performance of adhesive bonds depends on the physico-chemical properties of the adhered surfaces. This research is focused on characterization of surfaces before bonding. In-situ examination of large surface materials, determine the group of methods that are preferred. The analytical methods should be non-destructive, enabling large surface analysis in relatively short time. In this work a spectroscopic method was tested that can be potentially applied for surface analysis. Four cases of surface condition were investigated that can be encountered either in the manufacturing process or during aircraft service. The first case is related to contamination of CFRP surface with hydraulic fluid. This fluid reacts with water forming a phosphoric acid that can etch the CFRP. Second considered case was related to silicone-based release agent contamination. These agents are used during the moulding process of composite panels. Third case involved moisture content in CFRP. Moisture content lowers the adhesion quality and leads to reduced performance of CFRP resulting in reduced performance of the adhesive bond. The last case concentrated on heat damage of CFRP. It was shown that laser induced fluorescence method can be useful for non-destructive evaluation of CFRP surface and some of the investigated contaminants can be easily detected.

Determination of the Shear Stress Distribution in a Laminate from the Applied Shear Resultant--A Simplified Shear Solution

NASA Technical Reports Server (NTRS)

Bednarcyk, Brett A.; Aboudi, Jacob; Yarrington, Phillip W.

2007-01-01

The simplified shear solution method is presented for approximating the through-thickness shear stress distribution within a composite laminate based on laminated beam theory. The method does not consider the solution of a particular boundary value problem, rather it requires only knowledge of the global shear loading, geometry, and material properties of the laminate or panel. It is thus analogous to lamination theory in that ply level stresses can be efficiently determined from global load resultants (as determined, for instance, by finite element analysis) at a given location in a structure and used to evaluate the margin of safety on a ply by ply basis. The simplified shear solution stress distribution is zero at free surfaces, continuous at ply boundaries, and integrates to the applied shear load. Comparisons to existing theories are made for a variety of laminates, and design examples are provided illustrating the use of the method for determining through-thickness shear stress margins in several types of composite panels and in the context of a finite element structural analysis.

The measurement of the transmission loss of single leaf walls and panels by an impulse method

NASA Astrophysics Data System (ADS)

Balilah, Y. A.; Gibbs, B. M.

1988-06-01

The standard methods of measurement and rating of sound insulation of panels and walls are generally time-consuming and require expensive and often bulky equipment. In addition, the methods establish only that there has been failure to comply with insulation requirements without indicating the mode of failure. An impulse technique is proposed for the measurement of walls and partitions in situ. The method requires the digital capture of a short duration signal generated by a loudspeaker, and the isolation of the direct component from other reflected and scattered components by time-of-flight methods and windowing. The signal, when transferred from the time to frequency domain by means of fast Fourier transforms, can yield the sound insulation of a partition expressed as a transfer function. Experimental problems in the use of this technique, including those resulting from sphericity of the incident wave front and concentric bending excitation of the partition, are identified and methods proposed for their elimination. Most of the results presented are of single leaf panels subjected to sound at normal incidence, although some measurements were undertaken at oblique incidence. The range of surface densities considered was 7-500 kg/m 2, the highest value corresponding to a brick and plaster wall of thickness 285 mm. Measurement is compared with theoretical prediction, at one-third octave intervals in a frequency range of 100-5000 Hz, or as a continuous function of frequency with a typical resolution of 12·5 Hz. The dynamic range of the measurement equipment sets an upper limit to the measurable transmission loss. For the equipment eventually employed this was represented by a random incidence value of 50 dB.

Rotor blade construction for circulation control aircraft

NASA Technical Reports Server (NTRS)

Carter, Sr., Donald R. (Inventor); Sedlak, Matthew (Inventor); Krauss, Timothy A. (Inventor)

1986-01-01

A circulation control aircraft rotor blade having a spanwise Coanda surface 16 and a plurality of spanwise extending flexible composite material panels 18 cooperating with the surface to define slots for the discharge of compressed air from within the blade with each panel having first flexure means 60 associated with screw adjustments 36 for establishing a slot opening preload and second flexure means 62 associated with screw adjustments 38 for establishing a slot maximum opening.

Toward a laminar-flow-control transport

NASA Technical Reports Server (NTRS)

Sturgeon, R. F.

1978-01-01

Analyses were conducted to define a practical design for an advanced technology laminar flow control (LRC) transport for initial passenger operation in the early 1990's. Mission requirements, appropriate design criteria, and level of technology for the study aircraft were defined. The characteristics of the selected configuration were established, aircraft and LFC subsystems compatible with the mission requirements were defined, and the aircraft was evaluated in terms of fuel efficiency. A wing design integrating the LFC ducting and metering system into advanced composite wing structure was developed, manufacturing procedures for the surface panel design were established, and environmental and structural testing of surface panel components were conducted. Test results revealed a requirement for relatively minor changes in the manufacturing procedures employed, but have shown the general compatibility of both the selected design and the use of composite materials with the requirements of LFC wing surface panels.

Measuring Humidity in Sealed Glass Encasements

NASA Technical Reports Server (NTRS)

West, James W.; Burkett, Cecil G.; Levine, Joel S.

2005-01-01

A technique has been devised for measuring the relative humidity levels in the protective helium/water vapor atmosphere in which the Declaration of Independence, the United States Constitution, and the Bill of Rights are encased behind glass panels on display at the National Archives in Washington, DC. The technique is noninvasive: it does not involve penetrating the encasements (thereby risking contamination or damage to the priceless documents) to acquire samples of the atmosphere. The technique could also be applied to similar glass encasements used to protect and display important documents and other precious objects in museums. The basic principle of the technique is straightforward: An encasement is maintained at its normal display or operating temperature (e.g., room temperature) while a portion of its glass front panel is chilled (see Figure 1) until condensed water droplets become visible on the inside of the panel. The relative humidity of the enclosed atmosphere can then be determined as a known function of the dew point, the temperature below which the droplets condense. Notwithstanding the straightforwardness of the basic principle, careful attention to detail is necessary to enable accurate determination of the dew point. In the initial application, the affected portion of the glass panel was cooled by contact with an aluminum plate that was cooled by a thermoelectric module, the exhaust heat of which was dissipated by a heat sink cooled by a fan. A thermocouple was used to measure the interior temperature of the aluminum plate, and six other thermocouples were used to measure the temperatures at six locations on the cooled outer surface of the glass panel (see Figure 2). Thermal grease was applied to the aluminum plate and the thermocouples to ensure close thermal contact. Power was supplied to the thermoelectric module in small increments, based on previous laboratory tests. A small flashlight and a magnifying glass were used to look for water droplets condensing on the inner surface of the glass. The temperature readings of the thermocouples were taken during cool-down and upon observing condensation. In determining the dew point, it was necessary to make a correction for the differences between the temperatures measured on the chilled outer surface of the glass and the temperature of the inner surface, where the condensation took place. The correction was derived from a laboratory test on a measurement setup that was nearly identical, except that the dew location on the inner surface was also instrumented with a thermocouple. The test showed that the temperature at the dew location on the inner surface of the glass panel was 0.9 C above the temperature determined from the measurements on the chilled outer surface of the panel.

Accurate Simulation of MPPT Methods Performance When Applied to Commercial Photovoltaic Panels

PubMed Central

2015-01-01

A new, simple, and quick-calculation methodology to obtain a solar panel model, based on the manufacturers' datasheet, to perform MPPT simulations, is described. The method takes into account variations on the ambient conditions (sun irradiation and solar cells temperature) and allows fast MPPT methods comparison or their performance prediction when applied to a particular solar panel. The feasibility of the described methodology is checked with four different MPPT methods applied to a commercial solar panel, within a day, and under realistic ambient conditions. PMID:25874262

Accurate simulation of MPPT methods performance when applied to commercial photovoltaic panels.

PubMed

Cubas, Javier; Pindado, Santiago; Sanz-Andrés, Ángel

2015-01-01

A new, simple, and quick-calculation methodology to obtain a solar panel model, based on the manufacturers' datasheet, to perform MPPT simulations, is described. The method takes into account variations on the ambient conditions (sun irradiation and solar cells temperature) and allows fast MPPT methods comparison or their performance prediction when applied to a particular solar panel. The feasibility of the described methodology is checked with four different MPPT methods applied to a commercial solar panel, within a day, and under realistic ambient conditions.

Solar panel cleaning robot

NASA Astrophysics Data System (ADS)

Nalladhimmu, Pavan Kumar Reddy; Priyadarshini, S.

2018-04-01

As the demand of electricity is increasing, there is need to using the renewable sources to produce the energy at present of power shortage, the use of solar energy could be beneficial to great extent and easy to get the maximum efficiency. There is an urgent in improving the efficiency of solar power generation. Current solar panels setups take a major power loss when unwanted obstructions cover the surface of the panels. To make solar energy more efficiency of solar array systems must be maximized efficiency evaluation of PV panels, that has been discussed with particular attention to the presence of dust on the efficiency of the PV panels have been highlighted. This paper gives the how the solar panel cleaning system works and designing of the cleaning system.

Vacuum-free, maskless patterning of Ni electrodes by laser reductive sintering of NiO nanoparticle ink and its application to transparent conductors.

PubMed

Lee, Daeho; Paeng, Dongwoo; Park, Hee K; Grigoropoulos, Costas P

2014-10-28

We introduce a method for direct patterning of Ni electrodes through selective laser direct writing (LDW) of NiO nanoparticle (NP) ink. High-resolution Ni patterns are generated from NiO NP thin films by a vacuum-free, lithography-free, and solution-processable route. In particular, a continuous wave laser is used for the LDW reductive sintering of the metal oxide under ambient conditions with the aid of reducing agents in the ink solvent. Thin (∼ 40 nm) Ni electrodes of glossy metallic surfaces with smooth morphology and excellent edge definition can be fabricated. By applying this method, we demonstrate a high transmittance (>87%), electrically conducting panel for a touch screen panel application. The resistivity of the Ni electrode is less than an order of magnitude higher compared to that of the bulk Ni. Mechanical bending test, tape-pull test, and ultrasonic bath test confirm the robust adhesion of the electrodes on glass and polymer substrates.

Electromagnetic panel deployment and retraction using the geomagnetic field in LEO satellite missions

NASA Astrophysics Data System (ADS)

Inamori, Takaya; Sugawara, Yoshiki; Satou, Yasutaka

2015-12-01

Increasingly, spacecraft are installed with large-area structures that are extended and deployed post-launch. These extensible structures have been applied in several missions for power generation, thermal radiation, and solar propulsion. Here, we propose a deployment and retraction method using the electromagnetic force generated when the geomagnetic field interacts with electric current flowing on extensible panels. The panels are installed on a satellite in low Earth orbit. Specifically, electrical wires placed on the extensible panels generate magnetic moments, which interfere with the geomagnetic field. The resulting repulsive and retraction forces enable panel deployment and retraction. In the proposed method, a satellite realizes structural deployment using simple electrical wires. Furthermore, the satellite can achieve not only deployment but also retraction for avoiding damage from space debris and for agile attitude maneuvers. Moreover, because the proposed method realizes quasi-static deployment and the retraction of panels by electromagnetic forces, low impulsive force is exerted on fragile panels. The electrical wires can also be used to detect the panel deployment and retraction and generate a large magnetic moment for attitude control. The proposed method was assessed in numerical simulations based on multibody dynamics. Simulation results shows that a small cubic satellite with a wire current of 25 AT deployed 4 panels (20 cm × 20 cm) in 500 s and retracted 4 panels in 100 s.

Toward development of a surface-enhanced Raman scattering (SERS)-based cancer diagnostic immunoassay panel.

PubMed

Granger, Jennifer H; Granger, Michael C; Firpo, Matthew A; Mulvihill, Sean J; Porter, Marc D

2013-01-21

Proteomic analyses of readily obtained human fluids (e.g., serum, urine, and saliva) indicate that the diagnosis of complex diseases will be enhanced by the simultaneous measurement of multiple biomarkers from such samples. This paper describes the development of a nanoparticle-based multiplexed platform that has the potential for simultaneous read-out of large numbers of biomolecules. For this purpose, we have chosen pancreatic adenocarcinoma (PA) as a test bed for diagnosis and prognosis. PA is a devastating form of cancer in which an estimated 86% of diagnoses resulted in death in the United States in 2010. The high mortality rate is due, in part, to the asymptomatic development of the disease and the dearth of sensitive diagnostics available for early detection. One promising route lies in the development of a serum biomarker panel that can generate a signature unique to early stage PA. We describe the design and development of a proof-of-concept PA biomarker immunoassay array coupled with surface-enhanced Raman scattering (SERS) as a sensitive readout method.

Integrated modeling analysis of a novel hexapod and its application in active surface

NASA Astrophysics Data System (ADS)

Yang, Dehua; Zago, Lorenzo; Li, Hui; Lambert, Gregory; Zhou, Guohua; Li, Guoping

2011-09-01

This paper presents the concept and integrated modeling analysis of a novel mechanism, a 3-CPS/RPPS hexapod, for supporting segmented reflectors for radio telescopes and eventually segmented mirrors of optical telescopes. The concept comprises a novel type of hexapod with an original organization of actuators hence degrees of freedom, based on a swaying arm based design concept. Afterwards, with specially designed connecting joints between panels/segments, an iso-static master-slave active surface concept can be achieved for any triangular and/or hexagonal panel/segment pattern. The integrated modeling comprises all the multifold sizing and performance aspects which must be evaluated concurrently in order to optimize and validate the design and the configuration. In particular, comprehensive investigation of kinematic behavior, dynamic analysis, wave-front error and sensitivity analysis are carried out, where, frequently used tools like MATLAB/SimMechanics, CALFEM and ANSYS are used. Especially, we introduce the finite element method as a competent approach for analyses of the multi-degree of freedom mechanism. Some experimental verifications already performed validating single aspects of the integrated concept are also presented with the results obtained.

77 FR 40411 - Open Meeting of the Taxpayer Advocacy Panel Face-to-Face Service Methods Project Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-09

... Face-to-Face Service Methods Project Committee AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Notice of meeting. SUMMARY: An open meeting of the Taxpayer Advocacy Panel Face-to-Face Service Methods... Act, 5 U.S.C. App. (1988) that a meeting of the Taxpayer Advocacy Panel Face-to-Face Service Methods...

77 FR 37101 - Open Meeting of the Taxpayer Advocacy Panel Face-to-Face Service Methods Project Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-20

... Face-to-Face Service Methods Project Committee AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Notice of meeting. SUMMARY: An open meeting of the Taxpayer Advocacy Panel Face-to-Face Service Methods... Act, 5 U.S.C. App. (1988) that a meeting of the Taxpayer Advocacy Panel Face-to-Face Service Methods...

77 FR 21157 - Open Meeting of the Taxpayer Advocacy Panel Face-to-Face Service Methods Project Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-09

... Face-to-Face Service Methods Project Committee AGENCY: Internal Revenue Service (IRS) Treasury. ACTION: Notice of meeting. SUMMARY: An open meeting of the Taxpayer Advocacy Panel Face-to-Face Service Methods... Act, 5 U.S.C. App. (1988) that a meeting of the Taxpayer Advocacy Panel Face-to-Face Service Methods...

DC current distribution mapping system of the solar panels using a HTS-SQUID gradiometer

NASA Astrophysics Data System (ADS)

Miyazaki, Shingo; Kasuya, Syohei; Mawardi Saari, Mohd; Sakai, Kenji; Kiwa, Toshihiko; Tsukamoto, Akira; Adachi, Seiji; Tanabe, Keiichi; Tsukada, Keiji

2014-05-01

Solar panels are expected to play a major role as a source of sustainable energy. In order to evaluate solar panels, non-destructive tests, such as defect inspections and response property evaluations, are necessary. We developed a DC current distribution mapping system of the solar panels using a High Critical Temperature Superconductor Superconducting Quantum Interference Device (HTS-SQUID) gradiometer with ramp edge type Josephson junctions. Two independent components of the magnetic fields perpendicular to the panel surface (∂Bz/∂x, ∂Bz/∂y) were detected. The direct current of the solar panel is visualized by calculating the composition of the two signal components, the phase angle, and mapping the DC current vector. The developed system can evaluate the uniformity of DC current distributions precisely and may be applicable for defect detection of solar panels.

Method and apparatus for an inflatable shell

NASA Technical Reports Server (NTRS)

Johnson, Christopher J. (Inventor)

2012-01-01

A method of assembling an inflatable shell of a structure comprises folding a plurality of shell sections about a set of fold lines and integrating the plurality of shell sections together with one another to form the shell. In another embodiment, an inflatable shell comprises a plurality of shell sections, each shell section having two pairs of fold lines for folding into stowage comprising a first gore section having a plurality of first gore panels layered and collectively folded about at a first set of fold lines. Each layer of the first gore panels and second gore panels are configured such that, once the first gore panel and second gore panel are attached to one another at the respective side edges of each panel, the lines of attachment forming a second set of fold lines for the shell section. A system and method for fabricating gore panels is also disclosed.

Development of beryllium honeycomb sandwich composite for structural and other related applications

NASA Technical Reports Server (NTRS)

Vogan, J. W.; Grant, L. A.

1972-01-01

The feasibility of fabricating large beryllium honeycomb panels was demonstrated. Both flat and curved sandwich structures were manufactured using practical, braze bonding techniques. The processes developed prove that metallurgically assembled beryllium honeycomb panels show decided potential where rigid, lightweight structures are required. Three panels, each 10 square feet in surface area, were fabricated, and radiographically inspected to determine integrity. This examination revealed a 97 percent braze in the final panel. It is believed that ceramic dies for forming and brazing would facilitate the fabrication techniques for higher production rates. Ceramic dies would yield a lower thermal gradient in the panel during the braze cycle. This would eliminate the small amount of face sheet wrinkling present in the panels. Hot forming the various panel components demonstrated efficient manufacturing techniques for scaling up and producing large numbers of hot formed beryllium components and panels. The beryllium honeycomb panel demonstrated very good vibrational loading characteristics under test with desirable damping characteristics.

The Influence of Projectile Trajectory Angle on the Simulated Impact Response of a Shuttle Leading Edge Wing Panel

NASA Technical Reports Server (NTRS)

Spellman, Regina L.; Jones, Lisa E.; Lyle, Karen H.; Jackson, Karen E.; Fasanella, Edwin L.

2005-01-01

In support of recommendations by the Columbia Accident Investigation Board, a team has been studying the effect of debris impacting the reinforced carbon-carbon panels of the shuttle leading edge. The objective of this study was to examine the effect of varying parameters of the debris trajectory on the damage tolerance. Impacts at the upper and lower surface and the apex of the leading edge were examined. For each location, trajectory variances included both the alpha and beta directions. The results of the analysis indicated in all cases the beta sweep decreased the amount of damage to the panel. The increases in alpha resulted in a significant increase in damage to the RCC panel. In particular, for the lower surface, where the alpha can increase by 10 degrees, there was a nearly 40% increase in the impulse. As a result, it is recommended that for future analyses, a 10 degree offset in alpha from the nominal trajectory is included for impacts on the lower surface. It is also recommended to assume a straight aft, or zero beta, trajectory for a more conservative analysis.

76 FR 18534 - Pacific Fishery Management Council; Public Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-04

.... SUMMARY: The review panel (Panel) for assessment methods for data-poor species will hold a work session that is open to the public. DATES: The Review of Assessment Methods for Data-Poor Species will be held... Panel will adjourn on Friday, April 29, 2011. ADDRESSES: The Review of Assessment Methods for Data-Poor...

77 FR 55525 - Open Meeting of the Taxpayer Advocacy Panel Face-to-Face Service Methods Project Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-10

... Face-to-Face Service Methods Project Committee AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Notice of meeting. SUMMARY: An open meeting of the Taxpayer Advocacy Panel Face-to-Face Service Methods Project Committee will be conducted. The Taxpayer Advocacy Panel is soliciting public comments, ideas, and...

17. DETAIL OF CONTROL PANEL FOR FILTER #9: CONTROL SWITCHES ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

17. DETAIL OF CONTROL PANEL FOR FILTER #9: CONTROL SWITCHES CONTROL BY PERCENTAGE OF VALVE OPENINGS INFLUENT, EFFLUENT, DRAINAGE, BACKWASH AND SURFACE WASH. - F. E. Weymouth Filtration Plant, 700 North Moreno Avenue, La Verne, Los Angeles County, CA

Uncertainties in predicting solar panel power output

NASA Technical Reports Server (NTRS)

Anspaugh, B.

1974-01-01

The problem of calculating solar panel power output at launch and during a space mission is considered. The major sources of uncertainty and error in predicting the post launch electrical performance of the panel are considered. A general discussion of error analysis is given. Examples of uncertainty calculations are included. A general method of calculating the effect on the panel of various degrading environments is presented, with references supplied for specific methods. A technique for sizing a solar panel for a required mission power profile is developed.

Efficacy of Fluon conditioning for capturing cerambycid beetles in different trap designs and rersistence on panel traps over time

Treesearch

Elizabeth E. Graham; Therese M. Poland

2012-01-01

Fluon PTFE is a fluoropolymer dispersion applied as a surface conditioner to cross-vane panel traps to enhance trap efficiency for cerambycid beetles. We describe the results of three experiments to further optimize cerambycid traps of different designs and to test the effect of Fluon over time. We tested Fluon with Lindgren funnel and panel traps fitted with either...

Gas filled panel insulation

DOEpatents

Griffith, Brent T.; Arasteh, Dariush K.; Selkowitz, Stephen E.

1993-01-01

A structural or flexible highly insulative panel which may be translucent, is formed from multi-layer polymeric material in the form of an envelope surrounding a baffle. The baffle is designed so as to minimize heat transfer across the panel, by using material which forms substantially closed spaces to suppress convection of the low conductivity gas fill. At least a portion of the baffle carries a low emissivity surface for suppression of infrared radiation.

An indicative method for determination of the most hazardous changes in slopes of the subsidence basins in underground coal mining area in Ostrava (Czech Republic).

PubMed

Marschalko, Marian; Yilmaz, Isik; Křístková, Veronika; Fuka, Matěj; Kubečka, Karel; Bouchal, Tomáš

2013-01-01

Considering growing population and decreasing mineral resource reserves, the issue of undermining has been and shall remain very topical. This study aims to identify the mutual connections between mined out panels of a deposit and the final manifestations on the ground surface related to deep black coal mining. On the grounds of the identified connections, the study describes a method to simplify a common evaluation of undermined areas according to building site categories. Within the study, a demarcation of the areas was conducted in two localities in Czech Republic influenced by the effects of undermining in the Upper-Silesian Basin. In the allotment of the CSM Mine, an area unsuitable for founding structures was defined from the centre of the worked out workings to the distance of 175 m from the panel's edge, for which the corresponding break angle is 78.3°. Similarly, in the allotment of the Paskov Mine, an area unsuitable for founding structures was determined to the distance of 500 m from the panel's edge, for which the corresponding break angle is 50.2°. This demarcation may be implemented prior to deposit mining being aware of several physical-mechanical parameters of rocks in the deposit's overburden. Having mined out a particular section of a deposit, it is recommended to verify the values of break angle using the method described herein. The study may be applied as a relatively fast and effective method to evaluate future land use for planning.

Optical characterization of display screens by speckle-contrast measurements

NASA Astrophysics Data System (ADS)

Pozo, Antonio M.; Castro, José J.; Rubiño, Manuel

2012-10-01

In recent years, the flat-panel display (FPD) technology has undergone great development. Currently, FPDs are present in many devices. A significant element in FPD manufacturing is the display front surface. Manufacturers sell FPDs with different types of front surface which can be matte (also called anti-glare) or glossy screens. Users who prefer glossy screens consider images shown in these types of displays to have more vivid colours compared with matte-screen displays. However, external light sources may cause unpleasant reflections on the glossy screens. These reflections can be reduced by a matte treatment in the front surface of FPDs. In this work, we present a method to characterize the front surface of FPDs using laser speckle patterns. We characterized three FPDs: a Samsung XL2370 LCD monitor of 23" with matte screen, a Toshiba Satellite A100 laptop of 15.4" with glossy screen, and a Papyre electronic book reader. The results show great differences in speckle contrast values for the three screens characterized and, therefore, this work shows the feasibility of this method for characterizing and comparing FPDs which have different types of front surfaces.

Computation of wind tunnel wall effects for complex models using a low-order panel method

NASA Technical Reports Server (NTRS)

Ashby, Dale L.; Harris, Scott H.

1994-01-01

A technique for determining wind tunnel wall effects for complex models using the low-order, three dimensional panel method PMARC (Panel Method Ames Research Center) has been developed. Initial validation of the technique was performed using lift-coefficient data in the linear lift range from tests of a large-scale STOVL fighter model in the National Full-Scale Aerodynamics Complex (NFAC) facility. The data from these tests served as an ideal database for validating the technique because the same model was tested in two wind tunnel test sections with widely different dimensions. The lift-coefficient data obtained for the same model configuration in the two test sections were different, indicating a significant influence of the presence of the tunnel walls and mounting hardware on the lift coefficient in at least one of the two test sections. The wind tunnel wall effects were computed using PMARC and then subtracted from the measured data to yield corrected lift-coefficient versus angle-of-attack curves. The corrected lift-coefficient curves from the two wind tunnel test sections matched very well. Detailed pressure distributions computed by PMARC on the wing lower surface helped identify the source of large strut interference effects in one of the wind tunnel test sections. Extension of the technique to analysis of wind tunnel wall effects on the lift coefficient in the nonlinear lift range and on drag coefficient will require the addition of boundary-layer and separated-flow models to PMARC.

Cross-Beam Laser Joining of AA 6111 to Galvanized Steel in a Coach Peel Configuration

NASA Astrophysics Data System (ADS)

Yang, Guang; Mohammadpour, Masoud; Yazdian, Nima; Ma, Junjie; Carlson, Blair; Wang, Hui-Ping; Kovacevic, Radovan

2017-06-01

Cross-beam laser joining of aluminum alloy 6111 to hot-dip galvanized steel in the coach-peel configuration was investigated with the addition of AA 4047 filler wire. The filler material was not only brazed onto the galvanized steel but also partially fusion-welded with the aluminum panel. Through adjusting the laser power to 3.4 kW, a desirable wetting and spreading of filler wire on both panel surfaces could be achieved, and the thickness of intermetallic layer in the middle section of the interface between the weld bead and steel was less than 2 μm. To better understand the solid/liquid interfacial reaction at the brazing interface, two rotary Gaussian heat source models were introduced to simulate the temperature distribution in the molten pool by using the finite element method. Joint properties were examined in terms of microstructure and mechanical properties. During the tensile test, the fracture of coupons took place at the aluminum side rather than along the interface between the intermetallic layer and steel panel. No failure occurred during the three-point bending test.

Combined distributed and concentrated transducer network for failure indication

NASA Astrophysics Data System (ADS)

Ostachowicz, Wieslaw; Wandowski, Tomasz; Malinowski, Pawel

2010-03-01

In this paper algorithm for discontinuities localisation in thin panels made of aluminium alloy is presented. Mentioned algorithm uses Lamb wave propagation methods for discontinuities localisation. Elastic waves were generated and received using piezoelectric transducers. They were arranged in concentrated arrays distributed on the specimen surface. In this way almost whole specimen could be monitored using this combined distributed-concentrated transducer network. Excited elastic waves propagate and reflect from panel boundaries and discontinuities existing in the panel. Wave reflection were registered through the piezoelectric transducers and used in signal processing algorithm. Proposed processing algorithm consists of two parts: signal filtering and extraction of obstacles location. The first part was used in order to enhance signals by removing noise from them. Second part allowed to extract features connected with wave reflections from discontinuities. Extracted features damage influence maps were a basis to create damage influence maps. Damage maps indicated intensity of elastic wave reflections which corresponds to obstacles coordinates. Described signal processing algorithms were implemented in the MATLAB environment. It should be underlined that in this work results based only on experimental signals were presented.

Weight optimal design of lateral wing upper covers made of composite materials

NASA Astrophysics Data System (ADS)

Barkanov, Evgeny; Eglītis, Edgars; Almeida, Filipe; Bowering, Mark C.; Watson, Glenn

2016-09-01

The present investigation is devoted to the development of a new optimal design of lateral wing upper covers made of advanced composite materials, with special emphasis on closer conformity of the developed finite element analysis and operational requirements for aircraft wing panels. In the first stage, 24 weight optimization problems based on linear buckling analysis were solved for the laminated composite panels with three types of stiffener, two stiffener pitches and four load levels, taking into account manufacturing, reparability and damage tolerance requirements. In the second stage, a composite panel with the best weight/design performance from the previous study was verified by nonlinear buckling analysis and optimization to investigate the effect of shear and fuel pressure on the performance of stiffened panels, and their behaviour under skin post-buckling. Three rib-bay laminated composite panels with T-, I- and HAT-stiffeners were modelled with ANSYS, NASTRAN and ABAQUS finite element codes to study their buckling behaviour as a function of skin and stiffener lay-ups, stiffener height, stiffener top and root width. Owing to the large dimension of numerical problems to be solved, an optimization methodology was developed employing the method of experimental design and response surface technique. Optimal results obtained in terms of cross-sectional areas were verified successfully using ANSYS and ABAQUS shared-node models and a NASTRAN rigid-linked model, and were used later to estimate the weight of the Advanced Low Cost Aircraft Structures (ALCAS) lateral wing upper cover.

PERFORMANCE EVALUATION OF A SUSTAINABLE AND ENERGY EFFICIENT RE-ROOFING TECHNOLOGY USING FIELD-TEST DATA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biswas, Kaushik; Miller, William A; Childs, Phillip W

2011-01-01

Three test attics were constructed to evaluate a new sustainable method of re-roofing utilizing photo-voltaic (PV) laminates, metal roofing panels, and PCM heat sink in the Envelope Systems Research Apparatus (ESRA) facility in the ORNL campus. Figure 1 is a picture of the three attic roofs located adjacent to each other. The leftmost roof is the conventional shingle roof, followed by the metal panel roof incorporating the cool-roof coating, and third from left is the roof with the PCM. On the PCM roof, the PV panels are seen as well; they're labelled from left-to-right as panels 5, 6 and 7.more » The metal panel roof consists of three metal panels with the cool-roof coating; in further discussion this is referred to as the infrared reflective (IRR) metal roof. The IRR metal panels reflect the incoming solar radiation and then quickly re-emit the remaining absorbed portion, thereby reducing the solar heat gain of the attic. Surface reflectance of the panels were measured using a Solar Spectrum Reflectometer. In the 0.35-2.0 {mu}m wavelength interval, which accounts for more than 94% of the solar energy, the IRR panels have an average reflectance of 0.303. In the infrared portion of the spectrum, the IRR panel reflectance is 0.633. The PCM roof consists of a layer of macro-encapsulated bio-based PCM at the bottom, followed by a 2-cm thick layer of dense fiberglass insulation with a reflective surface on top, and metal panels with pre-installed PV laminates on top. The PCM has a melting point of 29 C (84.2 F) and total enthalpy between 180 and 190 J/g. The PCM was macro-packaged in between two layers of heavy-duty plastic foil forming arrays of PCM cells. Two air cavities, between PCM cells and above the fiberglass insulation, helped the over-the-deck natural air ventilation. It is anticipated that during summer, this extra ventilation will help in reducing the attic-generated cooling loads. The extra ventilation, in conjunction with the PCM heat sink, are used to minimize thermal stresses due to the PV laminates on sunny days. In PV laminates sunlight is converted into electricity and heat simultaneous. In case of building integrated applications, a relatively high solar absorption of amorphous silicon laminates can be utilized during the winter for solar heating purposes with PCM providing necessary heat storage capacity. However, PV laminates may also generate increased building cooling loads during the summer months. Therefore, in this project, the PCM heat sink was to minimize summer heat gains as well. The PCM-fibreglass-PV assembly and the IRR metal panels are capable of being installed directly on top of existing shingle roofs during re-roofing, precluding the need for recycling or disposal of waste materials. The PV laminates installed on the PCM attic are PVL-144 models from Uni-Solar. Each laminate contains 22 triple junction amorphous silicon solar cells connected in series. The silicon cells are of dimensions 356 mm x 239 mm (14-in. x 9.4-in.). The PVL-144 laminate is encapsulated in durable ETFE (poly-ethylene-co-tetrafluoroethylene) high light-transmissive polymer. Table 1 lists the power, voltage and current ratings of the PVL-144 panel.« less

Modal analysis and dynamic stresses for acoustically excited shuttle insulation tiles

NASA Technical Reports Server (NTRS)

Ojalvo, I. U.; Ogilvie, P. L.

1975-01-01

Improvements and extensions to the RESIST computer program developed for determining the normalized modal stress response of shuttle insulation tiles are described. The new version of RESIST can accommodate primary structure panels with closed-cell stringers, in addition to the capability for treating open-cell stringers. In addition, the present version of RESIST numerically solves vibration problems several times faster than its predecessor. A new digital computer program, titled ARREST (Acoustic Response of Reusable Shuttle Tiles) is also described. Starting with modal information contained on output tapes from RESIST computer runs, ARREST determines RMS stresses, deflections and accelerations of shuttle panels with reusable surface insulation tiles. Both programs are applicable to stringer stiffened structural panels with or without reusable surface insulation titles.

Photovoltaic module mounting system

DOEpatents

Miros, Robert H. J.; Mittan, Margaret Birmingham; Seery, Martin N; Holland, Rodney H

2012-09-18

A solar array mounting system having unique installation, load distribution, and grounding features, and which is adaptable for mounting solar panels having no external frame. The solar array mounting system includes flexible, pedestal-style feet and structural links connected in a grid formation on the mounting surface. The photovoltaic modules are secured in place via the use of attachment clamps that grip the edge of the typically glass substrate. The panel mounting clamps are then held in place by tilt brackets and/or mid-link brackets that provide fixation for the clamps and align the solar panels at a tilt to the horizontal mounting surface. The tilt brackets are held in place atop the flexible feet and connected link members thus creating a complete mounting structure.

Photovoltaic module mounting system

DOEpatents

Miros, Robert H. J. [Fairfax, CA; Mittan, Margaret Birmingham [Oakland, CA; Seery, Martin N [San Rafael, CA; Holland, Rodney H [Novato, CA

2012-04-17

A solar array mounting system having unique installation, load distribution, and grounding features, and which is adaptable for mounting solar panels having no external frame. The solar array mounting system includes flexible, pedestal-style feet and structural links connected in a grid formation on the mounting surface. The photovoltaic modules are secured in place via the use of attachment clamps that grip the edge of the typically glass substrate. The panel mounting clamps are then held in place by tilt brackets and/or mid-link brackets that provide fixation for the clamps and align the solar panels at a tilt to the horizontal mounting surface. The tilt brackets are held in place atop the flexible feet and connected link members thus creating a complete mounting structure.

Integrated analysis on static/dynamic aeroelasticity of curved panels based on a modified local piston theory

NASA Astrophysics Data System (ADS)

Yang, Zhichun; Zhou, Jian; Gu, Yingsong

2014-10-01

A flow field modified local piston theory, which is applied to the integrated analysis on static/dynamic aeroelastic behaviors of curved panels, is proposed in this paper. The local flow field parameters used in the modification are obtained by CFD technique which has the advantage to simulate the steady flow field accurately. This flow field modified local piston theory for aerodynamic loading is applied to the analysis of static aeroelastic deformation and flutter stabilities of curved panels in hypersonic flow. In addition, comparisons are made between results obtained by using the present method and curvature modified method. It shows that when the curvature of the curved panel is relatively small, the static aeroelastic deformations and flutter stability boundaries obtained by these two methods have little difference, while for curved panels with larger curvatures, the static aeroelastic deformation obtained by the present method is larger and the flutter stability boundary is smaller compared with those obtained by the curvature modified method, and the discrepancy increases with the increasing of curvature of panels. Therefore, the existing curvature modified method is non-conservative compared to the proposed flow field modified method based on the consideration of hypersonic flight vehicle safety, and the proposed flow field modified local piston theory for curved panels enlarges the application range of piston theory.

Solutions to Kuessner's integral equation in unsteady flow using local basis functions

NASA Technical Reports Server (NTRS)

Fromme, J. A.; Halstead, D. W.

1975-01-01

The computational procedure and numerical results are presented for a new method to solve Kuessner's integral equation in the case of subsonic compressible flow about harmonically oscillating planar surfaces with controls. Kuessner's equation is a linear transformation from pressure to normalwash. The unknown pressure is expanded in terms of prescribed basis functions and the unknown basis function coefficients are determined in the usual manner by satisfying the given normalwash distribution either collocationally or in the complex least squares sense. The present method of solution differs from previous ones in that the basis functions are defined in a continuous fashion over a relatively small portion of the aerodynamic surface and are zero elsewhere. This method, termed the local basis function method, combines the smoothness and accuracy of distribution methods with the simplicity and versatility of panel methods. Predictions by the local basis function method for unsteady flow are shown to be in excellent agreement with other methods. Also, potential improvements to the present method and extensions to more general classes of solutions are discussed.

Prediction of forces and moments for hypersonic flight vehicle control effectors

NASA Technical Reports Server (NTRS)

Maughmer, Mark D.; Long, Lyle N.; Guilmette, Neal; Pagano, Peter

1993-01-01

This research project includes three distinct phases. For completeness, all three phases of the work are briefly described in this report. The goal was to develop methods of predicting flight control forces and moments for hypersonic vehicles which could be used in a preliminary design environment. The first phase included a preliminary assessment of subsonic/supersonic panel methods and hypersonic local flow inclination methods for such predictions. While these findings clearly indicated the usefulness of such methods for conceptual design activities, deficiencies exist in some areas. Thus, a second phase of research was conducted in which a better understanding was sought for the reasons behind the successes and failures of the methods considered, particularly for the cases at hypersonic Mach numbers. This second phase involved using computational fluid dynamics methods to examine the flow fields in detail. Through these detailed predictions, the deficiencies in the simple surface inclination methods were determined. In the third phase of this work, an improvement to the surface inclination methods was developed. This used a novel method for including viscous effects by modifying the geometry to include the viscous/shock layer.

Deterministic and reliability based optimization of integrated thermal protection system composite panel using adaptive sampling techniques

NASA Astrophysics Data System (ADS)

Ravishankar, Bharani

Conventional space vehicles have thermal protection systems (TPS) that provide protection to an underlying structure that carries the flight loads. In an attempt to save weight, there is interest in an integrated TPS (ITPS) that combines the structural function and the TPS function. This has weight saving potential, but complicates the design of the ITPS that now has both thermal and structural failure modes. The main objectives of this dissertation was to optimally design the ITPS subjected to thermal and mechanical loads through deterministic and reliability based optimization. The optimization of the ITPS structure requires computationally expensive finite element analyses of 3D ITPS (solid) model. To reduce the computational expenses involved in the structural analysis, finite element based homogenization method was employed, homogenizing the 3D ITPS model to a 2D orthotropic plate. However it was found that homogenization was applicable only for panels that are much larger than the characteristic dimensions of the repeating unit cell in the ITPS panel. Hence a single unit cell was used for the optimization process to reduce the computational cost. Deterministic and probabilistic optimization of the ITPS panel required evaluation of failure constraints at various design points. This further demands computationally expensive finite element analyses which was replaced by efficient, low fidelity surrogate models. In an optimization process, it is important to represent the constraints accurately to find the optimum design. Instead of building global surrogate models using large number of designs, the computational resources were directed towards target regions near constraint boundaries for accurate representation of constraints using adaptive sampling strategies. Efficient Global Reliability Analyses (EGRA) facilitates sequentially sampling of design points around the region of interest in the design space. EGRA was applied to the response surface construction of the failure constraints in the deterministic and reliability based optimization of the ITPS panel. It was shown that using adaptive sampling, the number of designs required to find the optimum were reduced drastically, while improving the accuracy. System reliability of ITPS was estimated using Monte Carlo Simulation (MCS) based method. Separable Monte Carlo method was employed that allowed separable sampling of the random variables to predict the probability of failure accurately. The reliability analysis considered uncertainties in the geometry, material properties, loading conditions of the panel and error in finite element modeling. These uncertainties further increased the computational cost of MCS techniques which was also reduced by employing surrogate models. In order to estimate the error in the probability of failure estimate, bootstrapping method was applied. This research work thus demonstrates optimization of the ITPS composite panel with multiple failure modes and large number of uncertainties using adaptive sampling techniques.

Dual-band infrared (DBIR) imaging inspections of Boeing 737 and KC-135 aircraft panels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Del Grande, N.K.; Dolan, K.W.; Durbin, P.F.

1993-08-27

We apply dual-band infrared (DBIR) imaging as a dynamic thermal tomography tool for wide area inspection of a Boeing 737 aircraft, and several Boeing KC-135 aircraft panels. Our analyses are discussed in this report. After flash-heating the aircraft skin, we record synchronized DBIR images every 40 ms, from onset to 8 seconds after the heat flash. We analyze selective DBIR image ratios which enhance surface temperature contrast and remove surface-emissivity clutter (from dirt, dents, tape, markings, ink, sealants, uneven paint, paint stripper, exposed metal and roughness variations). The Boeing 737 and KC-135 aircraft fuselage panels have varying percent thickness lossesmore » from corrosion. We established the correlation of percent thickness loss with surface temperature rise (above ambient) for a partially corroded F-18 wing box structure and several aluminum reference panels. Based on this correlation, lap splice temperatures rise 1{degrees}C per 24 {plus_minus} 5 % material loss at 0.4 s after the heat flash. We show tables, charts and temperature maps of typical lap splice material losses for the riveted (and bonded) Boeing 737, and the riveted (but unbonded) Boeing KC-135. We map the fuselage composite thermal inertia, based on the (inverse) slope of the surface temperature versus inverse square root of time. Composite thermal inertia maps characterize shallow skin defects within the lap splice at early times (<0.3 s) and deeper skin defects within the lap splice at late times (>0.4 s). Late time composite thermal inertia maps depict where corrosion-related thickness losses occur. Lap splice sites on a typical Boeing KC-135 panel with low composite thermal inertia values had high skin-thickness losses from corrosion.« less

Abrasion behavior of aluminum and composite skin coupons, stiffened skins and stiffened panels representative of transport airplane structures

NASA Technical Reports Server (NTRS)

Jackson, K. E.

1985-01-01

A three-phase investigation was conducted to compare the friction and wear response of aluminum and graphite-epoxy composite materials when subjected to loading conditions similar to those experienced by the skin panels on the underside of a transport airplane during an emergency belly landing on a runway surface. The first phase involved a laboratory test which used a standard belt sander to provide the sliding abrasive surface. Small skin-coupon test specimens were abraded over a range of pressures and velocities to determine the effects of these variables on the coefficient of friction and wear rate. The second phase involved abrading I-beam stiffened skins on actual runway surface over the same range of pressures and velocities used in the first phase. In the third phase, large stiffened panels which most closely resembled transport fuelage skin construction were abraded on a runway surface. This report presents results from each phase of the investigation and shows comparisons between the friction and wear behavior of the aluminum and graphite-epoxy composite materials.

High-accuracy optical extensometer based on coordinate transform in two-dimensional digital image correlation

NASA Astrophysics Data System (ADS)

Lv, Zeqian; Xu, Xiaohai; Yan, Tianhao; Cai, Yulong; Su, Yong; Zhang, Qingchuan

2018-01-01

In the measurement of plate specimens, traditional two-dimensional (2D) digital image correlation (DIC) is challenged by two aspects: (1) the slant optical axis (misalignment of the optical camera axis and the object surface) and (2) out-of-plane motions (including translations and rotations) of the specimens. There are measurement errors in the results measured by 2D DIC, especially when the out-of-plane motions are big enough. To solve this problem, a novel compensation method has been proposed to correct the unsatisfactory results. The proposed compensation method consists of three main parts: 1) a pre-calibration step is used to determine the intrinsic parameters and lens distortions; 2) a compensation panel (a rigid panel with several markers located at known positions) is mounted to the specimen to track the specimen's motion so that the relative coordinate transformation between the compensation panel and the 2D DIC setup can be calculated using the coordinate transform algorithm; 3) three-dimensional world coordinates of measuring points on the specimen can be reconstructed via the coordinate transform algorithm and used to calculate deformations. Simulations have been carried out to validate the proposed compensation method. Results come out that when the extensometer length is 400 pixels, the strain accuracy reaches 10 με no matter out-of-plane translations (less than 1/200 of the object distance) nor out-of-plane rotations (rotation angle less than 5°) occur. The proposed compensation method leads to good results even when the out-of-plane translation reaches several percents of the object distance or the out-of-plane rotation angle reaches tens of degrees. The proposed compensation method has been applied in tensile experiments to obtain high-accuracy results as well.

Environmental aging and degradation of multiwalled carbon nanotube reinforced polypropylene

EPA Science Inventory

The degradation of polypropylene (PP) and PP-multiwalled carbon nanotube (PP-MWCNT) panels during environmental weathering resulted in an increased degree of crystallinity, making them brittle, and creating surface cracks. The degradation led to a breakdown of the panels and incr...

LWH and ACH Helmet Hardware Study

DTIC Science & Technology

2015-11-30

initial attempts to perform impact tests using screws mounted in Kevlar composite panels resulted in little damage to the screws, but a lot of...stiffer and stronger than Kevlar panels, does not plastically deform (and therefore Figure 11. Typical ductile fracture surface resulting from a

40 CFR 211.203 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... entering the ear. This includes devices of which hearing protection may not be the primary function, but... -carrying case. (u) Primary Panel. The surface that is considered to be the front surface or that surface...

40 CFR 211.203 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... entering the ear. This includes devices of which hearing protection may not be the primary function, but... -carrying case. (u) Primary Panel. The surface that is considered to be the front surface or that surface...

40 CFR 211.203 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... entering the ear. This includes devices of which hearing protection may not be the primary function, but... -carrying case. (u) Primary Panel. The surface that is considered to be the front surface or that surface...

Studying the Issues in Laser Joining of Lightweight Materials in a Coach-Peel Joint Configuration

NASA Astrophysics Data System (ADS)

Yang, Guang

In the automotive industry, aluminum alloys have been widely used and partially replaced the conventional steel structures in order to decrease the weight of a car and improve its fuel efficiency. This Thesis focuses on the development of laser joining of light-weight materials, such as aluminum alloys and high-strength galvanized steels. Among different joint types, the coach-peel configuration is of a specific design that requires a heat source capable of heating up a large surface area of the joint. Coach-peel joints applied on the visible exterior of a car require a smooth transition from the weld surface to the panel surface and low surface roughness without any need for post-processing. Although these joints are used as non-load-bearing components, a desirable strength of the weld is also needed. A fusion-brazing process using a dual-beam laser allows the automotive components such as the roof and side member panels to be joined in a coach-peel configuration with a high surface quality as well as an acceptable strength of the weld. To improve the weld surface quality, processing parameters such as laser beam configuration, laser-wire position, and shielding gas parameters were optimized for joining of aluminum alloy to aluminum alloy. Laser power was optimized for dual-beam laser joining of aluminum alloy to galvanized steel at high speed. The feasibility of joining as-received panels with lubricant was also explored. The identification of strain hardening models of aluminum alloys was conducted for the mechanical finite element analysis of the joint. Control of the molten pool solidification through the selection of laser beam configuration is one approach to improve joint quality. Laser joining of aluminum alloy AA 6111-T4 coach peel panels with the addition of AA 4047 filler wire was investigated using three configurations of laser beam: a single beam, dual beams in-line with the weld bead, and dual beams aligned perpendicular to the weld bead (herein referred to as cross-beam). To compare the three joining processes, the transient heat distribution, cooling rates, and solidification rates were analyzed by three-dimensional finite element models using ANSYS. Microstructure evolution, tensile strength, fracture mechanisms, and surface roughness of joints were investigated accordingly. To improve the weld surface quality of aluminum joints, the laser-wire position and the gas parameters were optimized. Visualization of the gas flow by a CCD camera revealed the effects of nozzle shape, flow rate, inclination angle of the gas tube, nozzle position, and gas compositions (argon and helium) on the weld surface quality. The suppression of plasma plume and the effects of oxidation on the molten pool were illustrated in detail. With an optimized set of processing parameters, the weld surface roughness (Ra) of approximately 1 microm can be achieved. The feasibility of fabricating the aluminum alloy panel joint in the as-received condition, i.e., with stamping lubricant, by using the cross-beam laser was investigated. Two commercial mineral oils, Bonderite L-FM MP-404 and Ferrocote 61 MAL HCL, were applied onto clean panels prior to joining in order to simulate the conditions of the production environment. The formation and growth of hydrogen bubbles inside the molten pool, the stability of welding process, and the possible energy absorption capability of the porous weld were explained. Besides joining of similar materials, cross-beam laser was applied to join aluminum alloy 6111 to hot-dip galvanized steel in the coach-peel configuration. The filler material was not only brazed onto the galvanized steel but also partially fusion-welded with the aluminum panel. Through adjusting the laser power to 3.4 kW, a desirable wetting and spreading of filler wire on both panel surfaces could be achieved, and the thickness of intermetallic layer in the middle section of the interface between the weld bead and steel was less than 2 microm. To better understand the solid/liquid interfacial reaction at the brazing interface, two rotary Gaussian heat source models were introduced to simulate the temperature distribution in the molten pool by using the finite element method. Joint properties were examined in terms of microstructure and mechanical properties. Simulation of the mechanical response of a coach-peel joint is instructive for improvement of the joining process. The effective true stress-strain curve of fusion-brazed AA 4047 was difficult to obtain experimentally. Therefore, the von Mises isotropic flow function of the weld bead was inversely derived by image-based finite element analysis. Through iterative correction, the predicted tensile response of the coach-peel joint matched well with the experiment. The von Mises fracture stresses at the fusion zone boundary and the brazing interface were identified, respectively.

Mechanically durable carbon nanotube-composite hierarchical structures with superhydrophobicity, self-cleaning, and low-drag.

PubMed

Jung, Yong Chae; Bhushan, Bharat

2009-12-22

Superhydrophobic surfaces with high contact angle and low contact angle hysteresis exhibit a self-cleaning effect and low drag for fluid flow. The lotus (Nelumbo nucifera) leaf is one of the examples found in nature for superhydrophobic surfaces. For the development of superhydrophobic surfaces, which is important for various applications such as glass windows, solar panels, and microchannels, materials and fabrication methods need to be explored to provide mechanically durable surfaces. It is necessary to perform durability studies on these surfaces. Carbon nanotube (CNT), composite structures which would lead to superhydrophobicity, self-cleaning, and low-drag, were prepared using a spray method. As a benchmark, structured surfaces with lotus wax were also prepared to compare with the durability of CNT composite structures. To compare the durability of the various fabricated surfaces, waterfall/jet tests were conducted to determine the loss of superhydrophobicity by changing the flow time and pressure conditions. Wear and friction studies were also performed using an atomic force microscope (AFM) and a ball-on-flat tribometer. The changes in the morphology of the structured surfaces were examined by AFM and optical imaging. We find that superhydrophobic CNT composite structures showed good mechanical durability, superior to the structured surfaces with lotus wax, and may be suitable for real world applications.

Gas filled panel insulation

DOEpatents

Griffith, B.T.; Arasteh, D.K.; Selkowitz, S.E.

1993-12-14

A structural or flexible highly insulative panel which may be translucent, is formed from multi-layer polymeric material in the form of an envelope surrounding a baffle. The baffle is designed so as to minimize heat transfer across the panel, by using material which forms substantially closed spaces to suppress convection of the low conductivity gas fill. At least a portion of the baffle carries a low emissivity surface for suppression of infrared radiation. 18 figures.

Low cost fabrication of ablative heat shields

NASA Technical Reports Server (NTRS)

Cecka, A. M.; Schofield, W. C.

1972-01-01

A material and process study was performed using subscale panels in an attempt to reduce the cost of fabricating ablative heat shield panels. Although no improvements were made in the material formulation, a significant improvement was obtained in the processing methods compared to those employed in the previous work. The principal feature of the new method is the press filling and curing of the ablation material in a single step with the bonding and curing of the face sheet. This method was chosen to replace the hand troweling and autoclave curing procedure used previously. Double-curvature panels of the same size as the flat panels were fabricated to investigate fabrication problems. It was determined that the same materials and processes used for flat panels can be used to produce the curved panels. A design with severe curvatures consisting of radii of 24 x 48 inches was employed for evaluation. Ten low-density and ten high-density panels were fabricated. With the exception of difficulties related to short run non-optimum tooling, excellent panel filling and density uniformity were obtained.

Automotive body panel containing thermally exfoliated graphite oxide

NASA Technical Reports Server (NTRS)

Aksay, Ilhan A. (Inventor); Abdala, Ahmed (Inventor); Prud'Homme, Robert K. (Inventor); Adamson, Douglas (Inventor)

2011-01-01

An automotive body panel containing a polymer composite formed of at least one polymer and a modified graphite oxide material, which is a thermally exfoliated graphite oxide with a surface area of from about 300 m.sup.2/g to 2600 m.sup.2/g.

Radiative, actively cooled panel tests results

NASA Technical Reports Server (NTRS)

Shore, C. P.; Nowak, R. J.; Sharpe, E. L.

1978-01-01

The radiative, actively cooled panel designed to withstand a uniform incident heat flux of 136 kW/sq m to a 444 K surface temperature was evaluated. The test program consisted of preliminary static thermal mechanical loading and aerothermal flow tests. Test results are briefly discussed.

Thermal control system. [removing waste heat from industrial process spacecraft

NASA Technical Reports Server (NTRS)

Hewitt, D. R. (Inventor)

1983-01-01

The temperature of an exothermic process plant carried aboard an Earth orbiting spacecraft is regulated using a number of curved radiator panels accurately positioned in a circular arrangement to form an open receptacle. A module containing the process is insertable into the receptacle. Heat exchangers having broad exterior surfaces extending axially above the circumference of the module fit within arcuate spacings between adjacent radiator panels. Banks of variable conductance heat pipes partially embedded within and thermally coupled to the radiator panels extend across the spacings and are thermally coupled to broad exterior surfaces of the heat exchangers by flanges. Temperature sensors monitor the temperature of process fluid flowing from the module through the heat exchanges. Thermal conduction between the heat exchangers and the radiator panels is regulated by heating a control fluid within the heat pipes to vary the effective thermal length of the heat pipes in inverse proportion to changes in the temperature of the process fluid.

Solar Powered Automobile Interior Climate Control System

NASA Technical Reports Server (NTRS)

Howard, Richard T. (Inventor)

2003-01-01

There is provided a climate control system for a parked vehicle that includes a solar panel, thermostatic switch, fans, and thermoelectric coolers. The solar panel can serve as the sole source of electricity for the system. The system affords convenient installation and removal by including solar panels that are removably attached to the exterior of a vehicle. A connecting wire electrically connects the solar panels to a housing that is removably mounted to a partially opened window on the vehicle. The thermostatic switch, fans, and thermoelectric coolers are included within the housing. The thermostatic switch alternates the direction of the current flow through the thermoelectric coolers to selectively heat or cool the interior of the vehicle. The interior surface of the thermoelectric coolers are in contact with interior heat sinks that have air circulated across them by an interior fan. Similarly, the exterior surface of the thermoelectric coolers are in contact with exterior heat sinks that have air circulated across them by an exterior fan.

Geometric and boundary element method simulations of acoustic reflections from rough, finite, or non-planar surfaces

NASA Astrophysics Data System (ADS)

Rathsam, Jonathan

This dissertation seeks to advance the current state of computer-based sound field simulations for room acoustics. The first part of the dissertation assesses the reliability of geometric sound-field simulations, which are approximate in nature. The second part of the dissertation uses the rigorous boundary element method (BEM) to learn more about reflections from finite reflectors: planar and non-planar. Acoustical designers commonly use geometric simulations to predict sound fields quickly. Geometric simulation of reflections from rough surfaces is still under refinement. The first project in this dissertation investigates the scattering coefficient, which quantifies the degree of diffuse reflection from rough surfaces. The main result is that predicted reverberation time varies inversely with scattering coefficient if the sound field is nondiffuse. Additional results include a flow chart that enables acoustical designers to gauge how sensitive predicted results are to their choice of scattering coefficient. Geometric acoustics is a high-frequency approximation to wave acoustics. At low frequencies, more pronounced wave phenomena cause deviations between real-world values and geometric predictions. Acoustical designers encounter the limits of geometric acoustics in particular when simulating the low frequency response from finite suspended reflector panels. This dissertation uses the rigorous BEM to develop an improved low-frequency radiation model for smooth, finite reflectors. The improved low frequency model is suggested in two forms for implementation in geometric models. Although BEM simulations require more computation time than geometric simulations, BEM results are highly accurate. The final section of this dissertation uses the BEM to investigate the sound field around non-planar reflectors. The author has added convex edges rounded away from the source side of finite, smooth reflectors to minimize coloration of reflections caused by interference from boundary waves. Although the coloration could not be fully eliminated, the convex edge increases the sound energy reflected into previously nonspecular zones. This excess reflected energy is marginally audible using a standard of 20 dB below direct sound energy. The convex-edged panel is recommended for use when designers want to extend reflected energy spatially beyond the specular reflection zone of a planar panel.

The method of neutron imaging as a tool for the study of the dynamics of water movement in wet aramid-based ballistic body armour panels

NASA Astrophysics Data System (ADS)

Reifler, Felix A.; Lehmann, Eberhard H.; Frei, Gabriel; May, Hans; Rossi, René

2006-07-01

A new non-destructive method based on neutron imaging (neutron radiography) to determine the exact water content in aramid-based soft body armour panels is presented. While investigating the ballistic resistance of aramid-based body armour panels under a wet condition, it is important to precisely determine their water content and its chronological development. Using the presented method, the influence of water amount and location on impact testing as well as its time dependence was shown. In the ballistic panels used, spreading of water strongly depended on the kind of quilting. Very fast water migration could be observed when the panels were held vertically. Some first results regarding the water distribution in wet panels immediately after the impact are presented. On the basis of the presented results, requirements for a standard for testing the performance of ballistic panels in the wet state are deduced.

Building Energy Storage Panel Based on Paraffin/Expanded Perlite: Preparation and Thermal Performance Study.

PubMed

Kong, Xiangfei; Zhong, Yuliang; Rong, Xian; Min, Chunhua; Qi, Chengying

2016-01-25

This study is focused on the preparation and performance of a building energy storage panel (BESP). The BESP was fabricated through a mold pressing method based on phase change material particle (PCMP), which was prepared in two steps: vacuum absorption and surface film coating. Firstly, phase change material (PCM) was incorporated into expanded perlite (EP) through a vacuum absorption method to obtain composite PCM; secondly, the composite PCM was immersed into the mixture of colloidal silica and organic acrylate, and then it was taken out and dried naturally. A series of experiments, including differential scanning calorimeter (DSC), scanning electron microscope (SEM), best matching test, and durability test, have been conducted to characterize and analyze the thermophysical property and reliability of PCMP. Additionally, the thermal performance of BESP was studied through a dynamic thermal property test. The results have showed that: (1) the surface film coating procedure can effectively solve the leakage problem of composite phase change material prepared by vacuum impregnation; (2) the optimum adsorption ratio for paraffin and EP was 52.5:47.5 in mass fraction, and the PCMP has good thermal properties, stability, and durability; and (3) in the process of dynamic thermal performance test, BESP have low temperature variation, significant temperature lagging, and large heat storage ability, which indicated the potential of BESP in the application of building energy efficiency.

Building Energy Storage Panel Based on Paraffin/Expanded Perlite: Preparation and Thermal Performance Study

PubMed Central

Kong, Xiangfei; Zhong, Yuliang; Rong, Xian; Min, Chunhua; Qi, Chengying

2016-01-01

This study is focused on the preparation and performance of a building energy storage panel (BESP). The BESP was fabricated through a mold pressing method based on phase change material particle (PCMP), which was prepared in two steps: vacuum absorption and surface film coating. Firstly, phase change material (PCM) was incorporated into expanded perlite (EP) through a vacuum absorption method to obtain composite PCM; secondly, the composite PCM was immersed into the mixture of colloidal silica and organic acrylate, and then it was taken out and dried naturally. A series of experiments, including differential scanning calorimeter (DSC), scanning electron microscope (SEM), best matching test, and durability test, have been conducted to characterize and analyze the thermophysical property and reliability of PCMP. Additionally, the thermal performance of BESP was studied through a dynamic thermal property test. The results have showed that: (1) the surface film coating procedure can effectively solve the leakage problem of composite phase change material prepared by vacuum impregnation; (2) the optimum adsorption ratio for paraffin and EP was 52.5:47.5 in mass fraction, and the PCMP has good thermal properties, stability, and durability; and (3) in the process of dynamic thermal performance test, BESP have low temperature variation, significant temperature lagging, and large heat storage ability, which indicated the potential of BESP in the application of building energy efficiency. PMID:28787870

Characterization of Dust on Solar Devices in Southern Nevada =

NASA Astrophysics Data System (ADS)

Sylva, Jason R.

Dust can impact the efficiency of solar energy collection devices, and in some arid environments, dust can reduce solar energy efficiency up to 30%. Reducing the impact of dust is therefore critical in the expansion of solar technology throughout regions where solar energy is utilized. Characterization of suspended and settled particulate matter can assist in developing strategies for dust mitigation. With the characterization of suspended and settled particulate in remote, rural, and urban environments, more informed decisions can be made regarding the selection of coating material on solar panels as well as developing cleaning and maintenance procedures. Particulate matter that deposits on a solar surface can potentially interact with solar radiation, precipitation, or even directly with the surface material itself. These interactions could lead to the formation of coatings that reduce/block radiation and/or degrade the integrity of the surface. When you extrapolate these possibilities to a larger scale preliminary characterization of dust will play a vital role when planning the construction of a solar energy facility. A variety of sampling techniques were employed to obtain particulate matter for characterization. These included direct collection of particulates from solar surfaces: via vacuum and wipe sample collection on panels, tacky dot adhesive slides and plain slides that were exposed at different intervals, desert vugs that are natural particulate collectors, as well as high volume air sampling for collection of suspended particulates. High volume air sampling was performed using glass fiber filters and 2 micron stainless steel screens. Direct collection of settled particulates was performed by sampling from solar surfaces, vugs, and by collection on exposed glass surfaces. Collection onto glass surfaces was achieved by setting up a plain microscope slide, tacky dot slides, and panes of glass. The sampling methodology allowed for the collection of samples for analyses using various analytical methods that included Raman microspectroscopy, pyrolysis gas chromatography mass spectrometry, ion chromatography and inductively coupled plasma mass spectrometry. These various methods allow for identification of organic and inorganic components as well the mineral distribution of suspended and settled particulate material. None None None None None

Development of fire-resistant wood structural panels

NASA Technical Reports Server (NTRS)

Vaughan, T. W.; Etzold, R.

1977-01-01

Structural panels made with Xylok 210 resin as the binder had a burn-through resistance at least equal to the structural panels made with Kerimid 500. Therefore, because of its comparative ease of handling, Xylok 210 was selected as the resin binder to provide the baseline panel for the study of a means of improving the flame-spread resistance of the structural panels. The final resin-filler system consisted of Xylok 210 binder with the addition of ammonium oxalate and ammonium phosphate to the strands of the surface layers, using 24% of each salt based upon the air-dry weight of the strands. This system resulted in a panel with a flame-spread code of about 60, a Class 2 classification. A standard phenolic based structural panel had a flame-spread greater than 200 for laboratory prepared panels. The burn-through tests indicated an average burn-through time of 588 seconds for the specimens made with the final system. This compares to an average burn-through time of 287 seconds for the standard phenolic base structural specimen. One full-size panel was made with the final system.

Automatic Defect Detection for TFT-LCD Array Process Using Quasiconformal Kernel Support Vector Data Description

PubMed Central

Liu, Yi-Hung; Chen, Yan-Jen

2011-01-01

Defect detection has been considered an efficient way to increase the yield rate of panels in thin film transistor liquid crystal display (TFT-LCD) manufacturing. In this study we focus on the array process since it is the first and key process in TFT-LCD manufacturing. Various defects occur in the array process, and some of them could cause great damage to the LCD panels. Thus, how to design a method that can robustly detect defects from the images captured from the surface of LCD panels has become crucial. Previously, support vector data description (SVDD) has been successfully applied to LCD defect detection. However, its generalization performance is limited. In this paper, we propose a novel one-class machine learning method, called quasiconformal kernel SVDD (QK-SVDD) to address this issue. The QK-SVDD can significantly improve generalization performance of the traditional SVDD by introducing the quasiconformal transformation into a predefined kernel. Experimental results, carried out on real LCD images provided by an LCD manufacturer in Taiwan, indicate that the proposed QK-SVDD not only obtains a high defect detection rate of 96%, but also greatly improves generalization performance of SVDD. The improvement has shown to be over 30%. In addition, results also show that the QK-SVDD defect detector is able to accomplish the task of defect detection on an LCD image within 60 ms. PMID:22016625

Automatic defect detection for TFT-LCD array process using quasiconformal kernel support vector data description.

PubMed

Liu, Yi-Hung; Chen, Yan-Jen

2011-01-01

Defect detection has been considered an efficient way to increase the yield rate of panels in thin film transistor liquid crystal display (TFT-LCD) manufacturing. In this study we focus on the array process since it is the first and key process in TFT-LCD manufacturing. Various defects occur in the array process, and some of them could cause great damage to the LCD panels. Thus, how to design a method that can robustly detect defects from the images captured from the surface of LCD panels has become crucial. Previously, support vector data description (SVDD) has been successfully applied to LCD defect detection. However, its generalization performance is limited. In this paper, we propose a novel one-class machine learning method, called quasiconformal kernel SVDD (QK-SVDD) to address this issue. The QK-SVDD can significantly improve generalization performance of the traditional SVDD by introducing the quasiconformal transformation into a predefined kernel. Experimental results, carried out on real LCD images provided by an LCD manufacturer in Taiwan, indicate that the proposed QK-SVDD not only obtains a high defect detection rate of 96%, but also greatly improves generalization performance of SVDD. The improvement has shown to be over 30%. In addition, results also show that the QK-SVDD defect detector is able to accomplish the task of defect detection on an LCD image within 60 ms.

Design and fabrication of a stringer stiffened discrete-tube actively cooled panel for a hypersonic aircraft

NASA Technical Reports Server (NTRS)

Anthony, F. M.; Halenbrook, R. G.

1981-01-01

A 0.61 x 1.22 m (2 x 4 ft) test panel was fabricated and delivered to the Langley Research Center for assessment of the thermal and structural features of the optimized panel design. The panel concept incorporated an aluminum alloy surface panel actively cooled by a network of discrete, parallel, redundant, counterflow passage interconnected with appropriate manifolding, and assembled by adhesive bonding. The cooled skin was stiffened with a mechanically fastened conventional substructure of stringers and frames. A 40 water/60 glycol solution was the coolant. Low pressure leak testing, radiography, holography and infrared scanning were applied at various stages of fabrication to assess integrity and uniformity. By nondestructively inspecting selected specimens which were subsequently tested to destruction, it was possible to refine inspection standards as applied to this cooled panel design.

Integration of LIDAR Data Into a Municipal GIS to Study Solar Radiation

NASA Astrophysics Data System (ADS)

Africani, P.; Bitelli, G.; Lambertini, A.; Minghetti, A.; Paselli, E.

2013-04-01

Identifying the right roofs to install solar panels inside a urban area is crucial for both private citizens and the whole local population. The aim is not easy because a lot of consideration must be made: insolation, orientation of the surface, size of the surface, shading due to topography, shading due to taller buildings next the surface, shading due to taller vegetation and other possible problems typical of urban areas like the presence of chimneys. Accuracy of data related to the analyzed surfaces is indeed fundamental, and also the detail of geometric models used to represent buildings and their roofs. The complexity that these roofs can reach is elevated. This work uses LiDAR data to obtain, with a semi-automatic technique, the full geometry of each roof part complementing the pre-existing building data in the municipal cartography. With this data is possible to evaluate the placement of solar panels on roofs of a whole city analyzing the solar potential of each building in detail. Other traditional techniques, like photogrammetry, need strong manual editing effort in order to identify slopes and insert vector on surfaces at the right height. Regarding LiDAR data, in order to perform accurate modelling, it is necessary to obtain an high density point cloud. The method proposed can also be used as a fast and linear workflow process for an area where LiDAR data are available and a municipal cartography already exist: LiDAR data can be furthermore successfully used to cross-check errors in pre-existent digital cartography that can remain otherwise hidden.

Text Line Detection from Rectangle Traffic Panels of Natural Scene

NASA Astrophysics Data System (ADS)

Wang, Shiyuan; Huang, Linlin; Hu, Jian

2018-01-01

Traffic sign detection and recognition is very important for Intelligent Transportation. Among traffic signs, traffic panel contains rich information. However, due to low resolution and blur in the rectangular traffic panel, it is difficult to extract the character and symbols. In this paper, we propose a coarse-to-fine method to detect the Chinese character on traffic panels from natural scenes. Given a traffic panel Color Quantization is applied to extract candidate regions of Chinese characters. Second, a multi-stage filter based on learning is applied to discard the non-character regions. Third, we aggregate the characters for text lines by Distance Metric Learning method. Experimental results on real traffic images from Baidu Street View demonstrate the effectiveness of the proposed method.

Study of advanced composite structural design concepts for an arrow wing supersonic cruise configuration, task 3

NASA Technical Reports Server (NTRS)

1978-01-01

A structural design study was conducted to assess the relative merits of structural concepts using advanced composite materials for an advanced supersonic aircraft cruising at Mach 2.7. The configuration and structural arrangement developed during Task I and II of the study, was used as the baseline configuration. Allowable stresses and strains were established for boron and advanced graphite fibers based on projected fiber properties available in the next decade. Structural concepts were designed and analyzed using graphite polyimide and boron polyimide, applied to stiffened panels and conventional sandwich panels. The conventional sandwich panels were selected as the structural concept to be used on the wing structure. The upper and lower surface panels of the Task I arrow wing were redesigned using high-strength graphite polyimide sandwich panels over the titanium spars and ribs. The ATLAS computer system was used as the basis for stress analysis and resizing the surface panels using the loads from the Task II study, without adjustment for change in aeroelastic deformation. The flutter analysis indicated a decrease in the flutter speed compared to the baseline titanium wing design. The flutter analysis indicated a decrease in the flutter speed compared to the baseline titanium wing design. The flutter speed was increased to that of the titanium wing, with a weight penalty less than that of the metallic airplane.

Development of Surfaces Optically Suitable for Flat Solar Panels

NASA Technical Reports Server (NTRS)

Desmet, D.; Jason, A.; Parr, A.

1977-01-01

Innovations in reflectometry techniques are described; and the development of an absorbing selective coating is discussed along with details of surface properties. Conclusions as to the parameterization desired for practical applications of selective surfaces are provided.

Modeling and simulation of the solar concentrator in photovoltaic systems through the application of a new BRDF function model

NASA Astrophysics Data System (ADS)

Plachta, Kamil

2016-04-01

The paper presents a new algorithm that uses a combination of two models of BRDF functions: Torrance-Sparrow model and HTSG model. The knowledge of technical parameters of a surface is especially useful in the construction of the solar concentrator. The concentrator directs the reflected solar radiation on the surface of photovoltaic panels, increasing the amount of incident radiance. The software applying algorithm allows to calculate surface parameters of the solar concentrator. Performed simulation showing the share of diffuse component and directional component in reflected stream for surfaces made from particular materials. The impact of share of each component in reflected stream on the efficiency of the solar concentrator and photovoltaic surface has also been described. Subsequently, simulation change the value of voltage, current and power output of monocrystalline photovoltaic panels installed in a solar concentrator system has been made for selected surface of materials solar concentrator.

Solar concentrator panel and gore testing in the JPL 25-foot space simulator

NASA Technical Reports Server (NTRS)

Dennison, E. W.; Argoud, M. J.

1981-01-01

The optical imaging characteristics of parabolic solar concentrator panels (or gores) have been measured using the optical beam of the JPL 25-foot space simulator. The simulator optical beam has been characterized, and the virtual source position and size have been determined. These data were used to define the optical test geometry. The point source image size and focal length have been determined for several panels. A flux distribution of a typical solar concentrator has been estimated from these data. Aperture photographs of the panels were used to determine the magnitude and characteristics of the reflecting surface errors. This measurement technique has proven to be highly successful at determining the optical characteristics of solar concentrator panels.

Domain decomposition and matching for time-domain analysis of motions of ships advancing in head sea

NASA Astrophysics Data System (ADS)

Tang, Kai; Zhu, Ren-chuan; Miao, Guo-ping; Fan, Ju

2014-08-01

A domain decomposition and matching method in the time-domain is outlined for simulating the motions of ships advancing in waves. The flow field is decomposed into inner and outer domains by an imaginary control surface, and the Rankine source method is applied to the inner domain while the transient Green function method is used in the outer domain. Two initial boundary value problems are matched on the control surface. The corresponding numerical codes are developed, and the added masses, wave exciting forces and ship motions advancing in head sea for Series 60 ship and S175 containership, are presented and verified. A good agreement has been obtained when the numerical results are compared with the experimental data and other references. It shows that the present method is more efficient because of the panel discretization only in the inner domain during the numerical calculation, and good numerical stability is proved to avoid divergence problem regarding ships with flare.

A new fabrication method for precision antenna reflectors for space flight and ground test

NASA Technical Reports Server (NTRS)

Sharp, G. Richard; Wanhainen, Joyce S.; Ketelsen, Dean A.

1991-01-01

Communications satellites are using increasingly higher frequencies that require increasingly precise antenna reflectors for use in space. Traditional industry fabrication methods for space antenna reflectors employ successive modeling techniques using high- and low-temperature molds for reflector face sheets and then a final fit-up of the completed honeycomb sandwich panel antenna reflector to a master pattern. However, as new missions are planned at much higher frequencies, greater accuracies will be necessary than are achievable using these present methods. A new approach for the fabrication of ground-test solid-surface antenna reflectors is to build a rigid support structure with an easy-to-machine surface. This surface is subsequently machined to the desired reflector contour and coated with a radio-frequency-reflective surface. This method was used to fabricate a 2.7-m-diameter ground-test antenna reflector to an accuracy of better than 0.013 mm (0.0005 in.) rms. A similar reflector for use on spacecraft would be constructed in a similar manner but with space-qualified materials. The design, analysis, and fabrication of the 2.7-m-diameter precision antenna reflector for antenna ground tests and the extension of this technology to precision, space-based antenna reflectors are described.

Synchronized parameter optimization of the double freeform lenses illumination system used for the CF-LCoS pico-projectors

NASA Astrophysics Data System (ADS)

Chen, Enguo; Liu, Peng; Yu, Feihong

2012-10-01

A novel synchronized optimization method of multiple freeform surfaces is proposed and applied to double lenses illumination system design of CF-LCoS pico-projectors. Based on Snell's law and the energy conservation law, a series of first-order partial differential equations are derived for the multiple freeform surfaces of the initial system. By assigning the light deflection angle to each freeform surface, multiple surfaces can be obtained simultaneously by solving the corresponding equations, meanwhile the restricted angle on CF-LCoS is guaranteed. In order to improve the spatial uniformity, the multi-surfaces are synchronously optimized by using simplex algorithm for an extended LED source. Design example shows that the double lenses based illumination system, which employs a single 2 mm×2 mm LED chip and a CF-LCoS panel with a diagonal of 0.59 inches satisfies the needs of pico-projector. Moreover, analytical result indicates that the design method represents substantial improvement and practical significance over traditional CF-LCoS projection system, which could offer outstanding performance with both portability and low cost. The synchronized optimization design method could not only realize collimating and uniform illumination, but also could be introduced to other specific light conditions.

Evaluation of a Highly Anticlastic Panel with Tow Overlaps

NASA Technical Reports Server (NTRS)

Wu, K. Chauncey; Gurdal, Zafer

2007-01-01

A rectangular, variable-stiffness panel with tow overlaps was manufactured using an advanced tow placement machine. The cured panel had large anticlastic imperfections, with measured amplitudes of over two times the average panel thickness. These imperfections were not due to the overall steered-fiber layup or the tow overlaps, but instead resulted from local asymmetries in the laminate that were caused by a manufacturing oversight. In the nominal panel layup, fiber angles vary linearly from 60 degrees on the panel axial centerline to 30 degrees on the parallel edges. A geometrically nonlinear analysis was performed with a -280 degree Fahrenheit thermal load to simulate the postcure cooldown to room temperature. The predicted geometric imperfections correlated well with the measured panel shape. Unique structural test fixtures were then developed which greatly reduced these imperfections, but they also caused prestresses in the panel. Surface imperfections measured after the panel was installed in the test fixtures were used with nonlinear finite element analyses to predict these fixturing-induced prestresses. These prestresses were also included in structural analyses of panel end compression to failure, and the analytical results compared well with test data when both geometric and material nonlinearities were included.

Fire Resistance of Large-Scale Cross-Laminated Timber Panels

NASA Astrophysics Data System (ADS)

Henek, Vladan; Venkrbec, Václav; Novotný, Miloslav

2017-12-01

Wooden structures are increasingly being used in the construction of residential buildings. A common and often published reason to avoid wooden structures is their insufficient fire resistance, which reduces bearing capacity. For this reason, composite sandwich structures began to be designed to eliminate this drawback, as well as others. Recently, however, the trend is for a return to the original, wood-only variant and a search is underway for new technical means of improving the properties of such structures. Many timber structure technologies are known, but structures made from cross-laminated timber (CLT) panels have been used very often in recent years. CLT panels, also known as X-LAM, are currently gaining popularity in Europe. In the case of CLT panels composed of several layers of boards, they can be said to offer a certain advantage in that after the surface layer of a board has burnt and the subsurface layer has dried, oxygen is not drawn to the unburned wood for further combustion and thus the burning process ceases. CLT panels do not need to be specially modified or coated with fire resistant materials, although they are usually lined with gypsum-fibre fire resistant boards due to guidelines set out in the relevant standards. This paper presents a new method for the assessment of load-bearing perimeter walls fabricated from CLT panels without the use of an inner fire-retardant lining to ensure fire resistance at the level required by European standards (i.e. those harmonized for the Czech construction industry). The calculations were verified through laboratory tests which show that better parameters can be achieved during the classification of structures from the fire resistance point of view. The aim of the article is to utilize the results of assessment and testing by an accredited laboratory in order to demonstrate the possibilities of using CLT panels for the construction of multistorey as well as multi-purpose buildings in the Czech Republic.

Sizing and Pointing of Solar Panels and for Solar Thermal Applications

Atmospheric Science Data Center

2014-09-25

... on horizontal surface (kWh/m2/day) Amount of electromagnetic energy (solar radiation) incident on the surface of the earth. ... on horizontal surface (kWh/m2/day) Amount of electromagnetic energy (solar radiation) incident on the surface of the earth ...

Development of laminar flow control wing surface porous structure

NASA Technical Reports Server (NTRS)

Klotzsche, M.; Pearce, W.; Anderson, C.; Thelander, J.; Boronow, W.; Gallimore, F.; Brown, W.; Matsuo, T.; Christensen, J.; Primavera, G.

1984-01-01

It was concluded that the chordwise air collection method, which actually combines chordwise and spanwise air collection, is the best of the designs conceived up to this time for full chord laminar flow control (LFC). Its shallower ducting improved structural efficiency of the main wing box resulting in a reduction in wing weight, and it provided continuous support of the chordwise panel joints, better matching of suction and clearing airflow requirements, and simplified duct to suction source minifolding. Laminar flow control on both the upper and lower surfaces was previously reduced to LFC suction on the upper surface only, back to 85 percent chord. The study concludes that, in addition to reduced wing area and other practical advantages, this system would be lighter because of the increase in effective structural wing thickness.

Experimental Design for a Macrofoam Swab Study Relating the Recovery Efficiency and False Negative Rate to Low Concentrations of Two Bacillus anthracis Surrogates on Four Surface Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piepel, Gregory F.; Hutchison, Janine R.

2014-04-16

This report describes the experimental design for a laboratory study to quantify the recovery efficiencies and false negative rates of a validated, macrofoam swab sampling method for low concentrations of Bacillus anthracis Sterne (BAS) and Bacillus atrophaeus (BG) spores on four surface materials (stainless steel, glass, vinyl tile, plastic light cover panel). Two analytical methods (plating/counting and polymerase chain reaction) will be used. Only one previous study has investigated false negative as a function of affecting test factors. The surrogates BAS and BG have not been tested together in the same study previously. Hence, this study will provide for completingmore » gaps in the available information on the performance of macrofoam swab sampling at low concentrations.« less

Experimental Design for a Macrofoam-Swab Study Relating the Recovery Efficiency and False Negative Rate to Low Concentrations of Two Bacillus anthracis Surrogates on Four Surface Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piepel, Gregory F.; Hutchison, Janine R.

This report describes the experimental design for a laboratory study to quantify the recovery efficiencies and false negative rates of a validated, macrofoam-swab sampling method for low concentrations of Bacillus anthracis Sterne (BAS) and Bacillus atrophaeus (BG) spores on four surface materials (stainless steel, glass, vinyl tile, plastic light cover panel). Two analytical methods (culture and polymerase chain reaction) will be used. Only one previous study has investigated how the false negative rate depends on test factors. The surrogates BAS and BG have not been tested together in the same study previously. Hence, this study will provide for completing gapsmore » in the available information on the performance of macrofoam-swab sampling at low concentrations.« less

Results of the "Komplast" experiment on the long-term exposure of materials specimens on the ISS surface

NASA Astrophysics Data System (ADS)

Shumov, Andrey; Novikov, Lev

The "Komplast" materials experiment was designed by the Khrunichev State Research and Production Space Center together with Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University and other Russian scientific institutes, and has been carried out since 1998. The aim of the experiment is to study the complex effects of space factors on specimens of various materials. Eight “Komplast” panels fitted with material specimens equipped UV-sensors and temperature sensors were located on the International Space Station (ISS) Functional Cargo Block (FGB) module exterior surface. The panels were sent into orbit with the FGB when it launched on November 20, 1998. Two of these panels were subsequently returned to Earth by Space Shuttle Discovery after 12 years of LEO exposure. The uniqueness of the "Komplast" experiment determined by long duration of open space exposure, which is much longer than in other similar experiments. For example LDEF: 1984-1990, HEEI (Space Station "Mir"): 1996-1997, MISSE-1, -2 (ISS): 1,5-2 years. In this work reveals laboratory research results of some materials specimens, which had been exposed on “Komplast” panels. A distinctive feature of this research was additional irradiation of specimens by atomic oxygen and electrons with energies of ~ 1-8 MeV in laboratory. In the interpretation of the experiment results was taken into account the specimens exposure temperature conditions on the ISS exterior surface and the conditions of their sunlit, defined by the above-mentioned sensors readings. Lot of attention was paid to the investigation of rubber materials specimens. The deformation, mechanical and relaxation characteristics were defined for the specimens. Also were investigations the seals-ability of model rubber seals after the long-term outer exposure. It was determined conservation volumetric deformation and relaxation characteristics of the exposed specimens and the localization of structural changes in the thin surface layer of the exposed materials on surfaces in direct contact with the open space. Was investigated the elemental and molecular composition of the panel surface contaminations, which were caused by evaporation of components of the specimens of rubber materials. The data on the change in the strength of adhesive joints of different pairs of materials during their long-term operation in the space environment was obtained. Characteristics of the exposed specimens were compared with the control specimens, which were kept in laboratory conditions. According to the research of carbon plastic specimens with epoxy resin obtained experimental data on the stability of the macro and micro structure of carbon plastic, as well as a change in the strength characteristics after exposure. We obtain estimates of the influence of space factors on the carbon plastics structure and properties. By optical and electron microscopy were investigated craters on the surface of polished metal specimens and panels created by micrometeoroids and space debris impacts, as well as low-speed particles bonded to the surface. The elemental composition of substance in the craters and low-speed particles was determined, which enables to identify the origin of particles. The results obtained in the "Komplast" experiment allow giving a forecast changes in the properties of materials at their long-term operation in the ISS orbit. Are currently under exposure the remaining six panels "Komplast" on the surface of the FGB. Return and their detailed studying is considered in plans for further work.

Manufacture of a four-sheet complex component from different titanium alloys by superplastic forming

NASA Astrophysics Data System (ADS)

Allazadeh, M. R.; Zuelli, N.

2017-10-01

A superplastic forming (SPF) technology process was deployed to form a complex component with eight-pocket from a four-sheet sandwich panel sheetstock. Six sheetstock packs were composed of two core sheets made of Ti-6Al-4V or Ti-5Al-4Cr-4Mo-2Sn-2Zr titanium alloy and two skin sheets made of Ti-6Al-4V or Ti-6Al-2Sn-4Zr-2Mo titanium alloy in three different combinations. The sheets were welded with two subsequent welding patterns over the core and skin sheets to meet the required component's details. The applied welding methods were intermittent and continuous resistance seam welding for bonding the core sheets to each other and the skin sheets over the core panel, respectively. The final component configuration was predicted based on the die drawings and finite element method (FEM) simulations for the sandwich panels. An SPF system set-up with two inlet gas pipe feeding facilitated the trials to deliver two pressure-time load cycles acting simultaneously which were extracted from FEM analysis for specific forming temperature and strain rate. The SPF pressure-time cycles were optimized via GOM scanning and visually inspecting some sections of the packs in order to assess the levels of core panel formation during the inflation process of the sheetstock. Two sets of GOM scan results were compared via GOM software to inspect the surface and internal features of the inflated multisheet packs. The results highlighted the capability of the tested SPF process to form complex components from a flat multisheet pack made of different titanium alloys.

Foil Panel Mirrors for Nonimaging Applications

NASA Technical Reports Server (NTRS)

Kuyper, D. J.; Castillo, A. A.

1984-01-01

Large durable, lightweight mirrors made by bonding thick aluminum foil to honeycomb panels or other rigid, flat backings. Mirrors suitable for use as infrared shields, telescope doors, solar-furnance doors, advertising displays, or other reflectors that require low thermal emissivity and high specularity but do not require precise surface figure necessary for imaging.

Predictions of thermal buckling strengths of hypersonic aircraft sandwich panels using minimum potential energy and finite element methods

NASA Technical Reports Server (NTRS)

Ko, William L.

1995-01-01

Thermal buckling characteristics of hypersonic aircraft sandwich panels of various aspect ratios were investigated. The panel is fastened at its four edges to the substructures under four different edge conditions and is subjected to uniform temperature loading. Minimum potential energy theory and finite element methods were used to calculate the panel buckling temperatures. The two methods gave fairly close buckling temperatures. However, the finite element method gave slightly lower buckling temperatures than those given by the minimum potential energy theory. The reasons for this slight discrepancy in eigensolutions are discussed in detail. In addition, the effect of eigenshifting on the eigenvalue convergence rate is discussed.

Airborne sound transmission loss characteristics of wood-frame construction

NASA Astrophysics Data System (ADS)

Rudder, F. F., Jr.

1985-03-01

This report summarizes the available data on the airborne sound transmission loss properties of wood-frame construction and evaluates the methods for predicting the airborne sound transmission loss. The first part of the report comprises a summary of sound transmission loss data for wood-frame interior walls and floor-ceiling construction. Data bases describing the sound transmission loss characteristics of other building components, such as windows and doors, are discussed. The second part of the report presents the prediction of the sound transmission loss of wood-frame construction. Appropriate calculation methods are described both for single-panel and for double-panel construction with sound absorption material in the cavity. With available methods, single-panel construction and double-panel construction with the panels connected by studs may be adequately characterized. Technical appendices are included that summarize laboratory measurements, compare measurement with theory, describe details of the prediction methods, and present sound transmission loss data for common building materials.

Detecting photovoltaic solar panels using hyperspectral imagery and estimating solar power production

NASA Astrophysics Data System (ADS)

Czirjak, Daniel

2017-04-01

Remote sensing platforms have consistently demonstrated the ability to detect, and in some cases identify, specific targets of interest, and photovoltaic solar panels are shown to have a unique spectral signature that is consistent across multiple manufacturers and construction methods. Solar panels are proven to be detectable in hyperspectral imagery using common statistical target detection methods such as the adaptive cosine estimator, and false alarms can be mitigated through the use of a spectral verification process that eliminates pixels that do not have the key spectral features of photovoltaic solar panel reflectance spectrum. The normalized solar panel index is described and is a key component in the false-alarm mitigation process. After spectral verification, these solar panel arrays are confirmed on openly available literal imagery and can be measured using numerous open-source algorithms and tools. The measurements allow for the assessment of overall solar power generation capacity using an equation that accounts for solar insolation, the area of solar panels, and the efficiency of the solar panels conversion of solar energy to power. Using a known location with readily available information, the methods outlined in this paper estimate the power generation capabilities within 6% of the rated power.

Numerical Simulation of Thermal Performance of Glass-Fibre-Reinforced Polymer

NASA Astrophysics Data System (ADS)

Zhao, Yuchao; Jiang, Xu; Zhang, Qilin; Wang, Qi

2017-10-01

Glass-Fibre-Reinforced Polymer (GFRP), as a developing construction material, has a rapidly increasing application in civil engineering especially bridge engineering area these years, mainly used as decorating materials and reinforcing bars for now. Compared with traditional construction material, these kinds of composite material have obvious advantages such as high strength, low density, resistance to corrosion and ease of processing. There are different processing methods to form members, such as pultrusion and resin transfer moulding (RTM) methods, which process into desired shape directly through raw material; meanwhile, GFRP, as a polymer composite, possesses several particular physical and mechanical properties, and the thermal property is one of them. The matrix material, polymer, performs special after heated and endue these composite material a potential hot processing property, but also a poor fire resistance. This paper focuses on thermal performance of GFRP as panels and corresponding researches are conducted. First, dynamic thermomechanical analysis (DMA) experiment is conducted to obtain the glass transition temperature (Tg) of the object GFRP, and the curve of bending elastic modulus with temperature is calculated according to the experimental data. Then compute and estimate the values of other various thermal parameters through DMA experiment and other literatures, and conduct numerical simulation under two condition respectively: (1) the heat transfer process of GFRP panel in which the panel would be heated directly on the surface above Tg, and the hot processing under this temperature field; (2) physical and mechanical performance of GFRP panel under fire condition. Condition (1) is mainly used to guide the development of high temperature processing equipment, and condition (2) indicates that GFRP’s performance under fire is unsatisfactory, measures must be taken when being adopted. Since composite materials’ properties differ from each other and their high temperature parameters can’t be obtained through common methods, some parameters are estimated, the simulation is to guide the actual high temperature experiment, and the parameters will also be adjusted by then.

Inspection of the Space Shuttle External Tank SOFI Using Near-Field and Focused Millimeter Wave Nondestructive Testing Techniques

NASA Technical Reports Server (NTRS)

Kharkovsky, S.; Hepburn, F.; Walker, J.; Zoughi, R.

2005-01-01

The Space Shuttle Columbia's catastrophic failure has been attributed to a piece of external tank SOFI (Spray On Foam Insulation) striking the left wing of the orbiter causing significant damage to some of the reinforced carbon/carbon leading edge wing panels. Subsequently, several nondestructive testing (NDT) techniques have been considered for inspecting the external tank. One such method involves using millimeter waves which have been shown to easily penetrate through the foam and provide high resolution images of its interior structures. This paper presents the results of inspecting three different SOFI covered panels by reflectometers at millimeter wave frequencies, specifically at 100 GHz. Each panel was fitted with various embedded anomalies/inserts representing voids and unbonds of diferent shapes, sizes and locations within each panel. In conjunction with these reJqectome&rs, radiators including a focused lens antenna and a small horn antenna were used. The focused lens antenna provided for a footprint diameter of approximately 1.25 cm (0.5") at 25.4 cm (10") away from the lens surface. The horn antenna was primarily operated in its near-field for obtaining relatively high resolution images. These images were produced using 2 0 scanning mechanisms. Discussions of the difference between the capabilities of these two types of antennas (radiators) for the purpose of inspecting the SOFI as it relates to the produced images are also presented.

Sound transmission through a poroelastic layered panel

NASA Astrophysics Data System (ADS)

Nagler, Loris; Rong, Ping; Schanz, Martin; von Estorff, Otto

2014-04-01

Multi-layered panels are often used to improve the acoustics in cars, airplanes, rooms, etc. For such an application these panels include porous and/or fibrous layers. The proposed numerical method is an approach to simulate the acoustical behavior of such multi-layered panels. The model assumes plate-like structures and, hence, combines plate theories for the different layers. The poroelastic layer is modelled with a recently developed plate theory. This theory uses a series expansion in thickness direction with subsequent analytical integration in this direction to reduce the three dimensions to two. The same idea is used to model either air gaps or fibrous layers. The latter are modeled as equivalent fluid and can be handled like an air gap, i.e., a kind of `air plate' is used. The coupling of the layers is done by using the series expansion to express the continuity conditions on the surfaces of the plates. The final system is solved with finite elements, where domain decomposition techniques in combination with preconditioned iterative solvers are applied to solve the final system of equations. In a large frequency range, the comparison with measurements shows very good agreement. From the numerical solution process it can be concluded that different preconditioners for the different layers are necessary. A reuse of the Krylov subspace of the iterative solvers pays if several excitations have to be computed but not that much in the loop over the frequencies.

Use of Internet panels to conduct surveys.

PubMed

Hays, Ron D; Liu, Honghu; Kapteyn, Arie

2015-09-01

The use of Internet panels to collect survey data is increasing because it is cost-effective, enables access to large and diverse samples quickly, takes less time than traditional methods to obtain data for analysis, and the standardization of the data collection process makes studies easy to replicate. A variety of probability-based panels have been created, including Telepanel/CentERpanel, Knowledge Networks (now GFK KnowledgePanel), the American Life Panel, the Longitudinal Internet Studies for the Social Sciences panel, and the Understanding America Study panel. Despite the advantage of having a known denominator (sampling frame), the probability-based Internet panels often have low recruitment participation rates, and some have argued that there is little practical difference between opting out of a probability sample and opting into a nonprobability (convenience) Internet panel. This article provides an overview of both probability-based and convenience panels, discussing potential benefits and cautions for each method, and summarizing the approaches used to weight panel respondents in order to better represent the underlying population. Challenges of using Internet panel data are discussed, including false answers, careless responses, giving the same answer repeatedly, getting multiple surveys from the same respondent, and panelists being members of multiple panels. More is to be learned about Internet panels generally and about Web-based data collection, as well as how to evaluate data collected using mobile devices and social-media platforms.

The development of optimal lightweight truss-core sandwich panels

NASA Astrophysics Data System (ADS)

Langhorst, Benjamin Robert

Sandwich structures effectively provide lightweight stiffness and strength by sandwiching a low-density core between stiff face sheets. The performance of lightweight truss-core sandwich panels is enhanced through the design of novel truss arrangements and the development of methods by which the panels may be optimized. An introduction to sandwich panels is presented along with an overview of previous research of truss-core sandwich panels. Three alternative truss arrangements are developed and their corresponding advantages, disadvantages, and optimization routines are discussed. Finally, performance is investigated by theoretical and numerical methods, and it is shown that the relative structural efficiency of alternative truss cores varies with panel weight and load-carrying capacity. Discrete truss core sandwich panels can be designed to serve bending applications more efficiently than traditional pyramidal truss arrangements at low panel weights and load capacities. Additionally, discrete-truss cores permit the design of heterogeneous cores, which feature unit cells that vary in geometry throughout the panel according to the internal loads present at each unit cell's location. A discrete-truss core panel may be selectively strengthened to more efficiently support bending loads. Future research is proposed and additional areas for lightweight sandwich panel development are explained.

Development of a Pressure Box to Evaluate Reusable-Launch-Vehicle Cryogenic-Tank Panels

NASA Technical Reports Server (NTRS)

Ambur, Damodar R.; Sikora, Joseph; Maguire, James F.; Winn, Peter M.

1996-01-01

A cryogenic pressure-box test machine has been designed and is being developed to test full-scale reusable-launch-vehicle cryogenic-tank panels. This machine is equipped with an internal pressurization system, a cryogenic cooling system, and a heating system to simulate the mechanical and thermal loading conditions that are representative of a reusable-launch-vehicle mission profile. The cryogenic cooling system uses liquid helium and liquid nitrogen to simulate liquid hydrogen and liquid oxygen tank internal temperatures. A quartz lamp heating system is used for heating the external surface of the test panels to simulate cryogenic-tank external surface temperatures during re-entry of the launch vehicle. The pressurization system uses gaseous helium and is designed to be controlled independently of the cooling system. The tensile loads in the axial direction of the test panel are simulated by means of hydraulic actuators and a load control system. The hoop loads in the test panel are reacted by load-calibrated turnbuckles attached to the skin and frame elements of the test panel. The load distribution in the skin and frames can be adjusted to correspond to the tank structure by using these turnbuckles. The seal between the test panel and the cryogenic pressure box is made from a reinforced Teflon material which can withstand pressures greater than 52 psig at cryogenic temperatures. Analytical results and tests on prototype test components indicate that most of the cryogenic-tank loading conditions that occur in flight can be simulated in the cryogenic pressure-box test machine.

Forced sound transmission through a finite-sized single leaf panel subject to a point source excitation.

PubMed

Wang, Chong

2018-03-01

In the case of a point source in front of a panel, the wavefront of the incident wave is spherical. This paper discusses spherical sound waves transmitting through a finite sized panel. The forced sound transmission performance that predominates in the frequency range below the coincidence frequency is the focus. Given the point source located along the centerline of the panel, forced sound transmission coefficient is derived through introducing the sound radiation impedance for spherical incident waves. It is found that in addition to the panel mass, forced sound transmission loss also depends on the distance from the source to the panel as determined by the radiation impedance. Unlike the case of plane incident waves, sound transmission performance of a finite sized panel does not necessarily converge to that of an infinite panel, especially when the source is away from the panel. For practical applications, the normal incidence sound transmission loss expression of plane incident waves can be used if the distance between the source and panel d and the panel surface area S satisfy d/S>0.5. When d/S ≈0.1, the diffuse field sound transmission loss expression may be a good approximation. An empirical expression for d/S=0  is also given.

Environmental Performance of North American Wood Panel Manufacturing

Treesearch

R. Bergman; D. Kaestner; A. Taylor

2015-01-01

Manufacturing building products such as wood panels has environmental impacts, including contributions to climate change. This paper is a compilation of four studies quantifying these impacts using the life-cycle assessment (LCA) method on five wood-based panel products made in North America during 2012. LCA is an internationally accepted and standardized method for...

Life cycle impacts of North American wood panel Manufacturing

Treesearch

Richard Bergman; D. Kaestner; A. M. Taylor

2016-01-01

Manufacturing building products such as wood panels impacts the environment, including contributing to climate change. This study is a compilation of four studies quantifying these impacts using the life cycle assessment (LCA) method on five wood-based panel products made in North America during 2012. LCA is an internationally accepted and standardized method for...

Seasonal control skylight glazing panel with passive solar energy switching

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, J.V.

1983-10-25

A substantially transparent one-piece glazing panel is provided for generally horizontal mounting in a skylight. The panel is comprised of an repeated pattern of two alternating and contiguous linear optical elements; a first optical element being an upstanding generally right-triangular linear prism, and the second optical element being an upward-facing plano-cylindrical lens in which the planar surface is reflectively opaque and is generally in the same plane as the base of the triangular prism.

Mathematical simulation of efficiency of various shapes of solar panels for NASA geostationary satellites

NASA Astrophysics Data System (ADS)

Pandya, Raaghav; Raja, Hammad; Enriquez-Torres, Delfino; Serey-Roman, Maria Ignacia; Hassebo, Yasser; Marciniak, Małgorzata

2018-02-01

The purpose of this research is to analyze mathematically cylindrical shapes of flexible solar panels and compare their efficiency to the flat panels. The efficiency is defined to be the flux density, which is the ratio of the mathematical flux and the surface area. In addition we describe the trajectory of the Sun at specific locations: the North Pole, The Equator and a geostationary satellite above the Equator. The calculations were performed with software: Maple, Mathematica, and MATLAB.

Calculation of vortex lift effect for cambered wings by the suction analogy

NASA Technical Reports Server (NTRS)

Lan, C. E.; Chang, J. F.

1981-01-01

An improved version of Woodward's chord plane aerodynamic panel method for subsonic and supersonic flow is developed for cambered wings exhibiting edge separated vortex flow, including those with leading edge vortex flaps. The exact relation between leading edge thrust and suction force in potential flow is derived. Instead of assuming the rotated suction force to be normal to wing surface at the leading edge, new orientation for the rotated suction force is determined through consideration of the momentum principle. The supersonic suction analogy method is improved by using an effective angle of attack defined through a semi-empirical method. Comparisons of predicted results with available data in subsonic and supersonic flow are presented.

A Discontinuous Galerkin Method for Parabolic Problems with Modified hp-Finite Element Approximation Technique

NASA Technical Reports Server (NTRS)

Kaneko, Hideaki; Bey, Kim S.; Hou, Gene J. W.

2004-01-01

A recent paper is generalized to a case where the spatial region is taken in R(sup 3). The region is assumed to be a thin body, such as a panel on the wing or fuselage of an aerospace vehicle. The traditional h- as well as hp-finite element methods are applied to the surface defined in the x - y variables, while, through the thickness, the technique of the p-element is employed. Time and spatial discretization scheme based upon an assumption of certain weak singularity of double vertical line u(sub t) double vertical line 2, is used to derive an optimal a priori error estimate for the current method.

EPA/NASA/USAF Depainting Effort Concludes

NASA Technical Reports Server (NTRS)

Finckenor, Miria M.; Clark-Ingram, Marceia

2000-01-01

The final report contains strip rate data from all of the methods, lessons learned during processing, metallurgical evaluations of the panels, and summaries of corrosion and hydrogen embrittlement studies. Any changes in surface roughness, fatigue and tensile properties, and crack detectability are noted in the report. No process was singled out above the others, as companies should consider equipment and operational costs when complying with the Aerospace NESHAP (National Emission Standards for Hazardous Air Pollutants) and new OSHA (Occupational Safety and Health Administration) regulations.

Dispersion of Lamb waves in a honeycomb composite sandwich panel.

PubMed

Baid, Harsh; Schaal, Christoph; Samajder, Himadri; Mal, Ajit

2015-02-01

Composite materials are increasingly being used in advanced aircraft and aerospace structures. Despite their many advantages, composites are often susceptible to hidden damages that may occur during manufacturing and/or service of the structure. Therefore, safe operation of composite structures requires careful monitoring of the initiation and growth of such defects. Ultrasonic methods using guided waves offer a reliable and cost effective method for defects monitoring in advanced structures due to their long propagation range and their sensitivity to defects in their propagation path. In this paper, some of the useful properties of guided Lamb type waves are investigated, using analytical, numerical and experimental methods, in an effort to provide the knowledge base required for the development of viable structural health monitoring systems for composite structures. The laboratory experiments involve a pitch-catch method in which a pair of movable transducers is placed on the outside surface of the structure for generating and recording the wave signals. The specific cases considered include an aluminum plate, a woven composite laminate and an aluminum honeycomb sandwich panel. The agreement between experimental, numerical and theoretical results are shown to be excellent in certain frequency ranges, providing a guidance for the design of effective inspection systems. Copyright © 2014 Elsevier B.V. All rights reserved.

A first-order Green's function approach to supersonic oscillatory flow: A mixed analytic and numeric treatment

NASA Technical Reports Server (NTRS)

Freedman, M. I.; Sipcic, S.; Tseng, K.

1985-01-01

A frequency domain Green's Function Method for unsteady supersonic potential flow around complex aircraft configurations is presented. The focus is on the supersonic range wherein the linear potential flow assumption is valid. In this range the effects of the nonlinear terms in the unsteady supersonic compressible velocity potential equation are negligible and therefore these terms will be omitted. The Green's function method is employed in order to convert the potential flow differential equation into an integral one. This integral equation is then discretized, through standard finite element technique, to yield a linear algebraic system of equations relating the unknown potential to its prescribed co-normalwash (boundary condition) on the surface of the aircraft. The arbitrary complex aircraft configuration (e.g., finite-thickness wing, wing-body-tail) is discretized into hyperboloidal (twisted quadrilateral) panels. The potential and co-normalwash are assumed to vary linearly within each panel. The long range goal is to develop a comprehensive theory for unsteady supersonic potential aerodynamic which is capable of yielding accurate results even in the low supersonic (i.e., high transonic) range.

Boundary Layer Flow Control with a One Atmosphere Uniform Glow Discharge Surface Plasma

NASA Technical Reports Server (NTRS)

Roth, J. Reece; Sherman, Daniel M.; Wilkinson, Stephen P.

1998-01-01

Low speed wind tunnel data have been acquired for planar panels covered by a uniform, glow-discharge surface plasma in atmospheric pressure air known as the One Atmosphere Uniform Glow Discharge Plasma (OAUGDP). Streamwise and spanwise arrays of flush, plasma-generating surface electrodes have been studied in laminar, transitional, and fully turbulent boundary layer flow. Plasma between symmetric streamwise electrode strips caused large increases in panel drag, whereas asymmetric spanwise electrode configurations produced a significant thrust. Smoke wire flow visualization and mean velocity diagnostics show the primary cause of the phenomena to be a combination of mass transport and vortical structures induced by strong paraelectric ElectroHydroDynamic (EHD) body forces on the flow.

Adhesive particle shielding

DOEpatents

Klebanoff, Leonard Elliott [Dublin, CA; Rader, Daniel John [Albuquerque, NM; Walton, Christopher [Berkeley, CA; Folta, James [Livermore, CA

2009-01-06

An efficient device for capturing fast moving particles has an adhesive particle shield that includes (i) a mounting panel and (ii) a film that is attached to the mounting panel wherein the outer surface of the film has an adhesive coating disposed thereon to capture particles contacting the outer surface. The shield can be employed to maintain a substantially particle free environment such as in photolithographic systems having critical surfaces, such as wafers, masks, and optics and in the tools used to make these components, that are sensitive to particle contamination. The shield can be portable to be positioned in hard-to-reach areas of a photolithography machine. The adhesive particle shield can incorporate cooling means to attract particles via the thermophoresis effect.

Algorithm applying a modified BRDF function in Λ-ridge concentrator of solar radiation

NASA Astrophysics Data System (ADS)

Plachta, Kamil

2015-05-01

This paper presents an algorithm that uses the modified BRDF function. It allows the calculation of the parameters of Λ-ridge concentrator system. The concentrator directs reflected solar radiation on photovoltaic surface, increasing its efficiency. The efficiency of the concentrator depends on the surface characteristics of the material which it is made of, the angle of the photovoltaic panel and the resolution of the tracking system. It shows a method of modeling the surface by using the BRDF function and describes its basic parameters, e.g. roughness and the components of the reflected stream. A cost calculation of chosen models with presented in this article BRDF function modification has been made. The author's own simulation program allows to choose the appropriate material for construction of a Λ-ridge concentrator, generate micro surface of the material, and simulate the shape and components of the reflected stream.

Comparisons of the Maxwell and CLL Gas/Surface Interaction Models Using DSMC

NASA Technical Reports Server (NTRS)

Hedahl, Marc O.

1995-01-01

Two contrasting models of gas-surface interactions are studied using the Direct Simulation Monte Carlo (DSMC) method. The DSMC calculations examine differences in predictions of aerodynamic forces and heat transfer between the Maxwell and Cercignani-Lampis-Lord (CLL) models for flat plate configurations at freestream conditions corresponding to a 140 km orbit around Venus. The size of the flat plate is that of one of the solar panels on the Magellan spacecraft, and the freestream conditions are one of those experienced during aerobraking maneuvers. Results are presented for both a single flat plate and a two-plate configuration as a function of angle of attack and gas-surface accommodation coefficients. The two plate system is not representative of the Magellan geometry, but is studied to explore possible experiments that might be used to differentiate between the two gas surface interaction models.

New modeling method and mechanism analyses for active control of interior noise in an irregular enclosure using piezoelectric actuators.

PubMed

Geng, Hou C; Rao, Zhu S; Han, Zu S

2003-03-01

A new modeling method is developed in this paper for the active minimization of noise within a three-dimensional irregular enclosure using distributed lead zirconate titanate piezoelectric (PZT) actuators, and the control mechanisms for irregular enclosure are analyzed. The irregular enclosure is modeled with four rigid walls and two simply supported flexible panels, and PZT actuators are bound to one of the flexible panels. The process of the new modeling method is as follows. First, the modal coupling method is used to establish the motion equations, which contain important coefficients such as modal masses and modal coupling coefficients, etc., of acoustic-structural-piezoelectric coupling system. Then, the acoustic modes and the modal masses of irregular enclosure are calculated by numerical methods. Last, the modal coupling coefficients in motion equations are calculated according to the numerical results of the acoustic modes of irregular enclosure and the modes of two panels. The validity of this modeling method is verified by a regular hexahedron enclosure. Two cost functions are applied to this model. With the two cost functions, good results are obtained in minimizing the sound-pressure level (SPL) within irregular enclosure according to numerical investigations. By comparing the results obtained under controlled and uncontrolled states, the control mechanisms of the system are discussed. It is found that the control mechanisms vary with disturbance frequencies. At most disturbance frequencies, the SPL within enclosure is reduced by restructuring the modes of two panels simultaneously. When the disturbance frequency comes close to one of the natural frequencies of panel a, the dominant mode of panel a is suppressed, while the modes of panel b are reconstructed. While the disturbance frequency is near one of the natural frequencies of panel b, the modes of two panels are restructured at the same time.

Test and analysis of a stitched RFI graphite-epoxy panel with a fuel access door

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.; Waters, W. Allen, Jr.

1994-01-01

A stitched RFI graphite-epoxy panel with a fuel access door was analyzed using a finite element analysis and loaded to failure in compression. The panel was initially 56-inches long and 36.75-inches wide and the oval access door was 18-inches long and 15-inches wide. The panel was impact damaged with impact energy of 100 ft-lb prior to compressive loading; however, no impact damage was detectable visually or by A-scan. The panel carried a failure load of 695,000 Ib and global failure strain of .00494 in/in. Analysis indicated the panel would fail due to collapse at a load of 688,100 Ib. The test data indicate that the maximum strain in a region near the access door was .0096 in/in and analysis indicates a local surface strain of .010 in/in at the panel's failure load. The panel did not fail through the impact damage, but instead failed through bolt holes for attachment of the access door in a region of high strain.

Solar absorption surface panel

DOEpatents

Santala, Teuvo J.

1978-01-01

A composite metal of aluminum and nickel is used to form an economical solar absorption surface for a collector plate wherein an intermetallic compound of the aluminum and nickel provides a surface morphology with high absorptance and relatively low infrared emittance along with good durability.

Increasing the efficiency of solar thermal panels

NASA Astrophysics Data System (ADS)

Dobrnjac, M.; Latinović, T.; Dobrnjac, S.; Živković, P.

2016-08-01

The popularity of solar heating systems is increasing for several reasons. These systems are reliable, adaptable and pollution-free, because the renewable solar energy is used. There are many variants of solar systems in the market mainly constructed with copper pipes and absorbers with different quality of absorption surface. Taking into account the advantages and disadvantages of existing solutions, in order to increase efficiency and improve the design of solar panel, the innovative solution has been done. This new solar panel presents connection of an attractive design and the use of constructive appropriate materials with special geometric shapes. Hydraulic and thermotechnical tests that have been performed on this panel showed high hydraulic and structural stability. Further development of the solar panel will be done in the future in order to improve some noticed disadvantages.

Panel 1: A pulsating red giant star and a compact, hot white dwarf star orbit each other.

NASA Technical Reports Server (NTRS)

2002-01-01

Panel 1: A pulsating red giant star and a compact, hot white dwarf star orbit each other. Panel 2: The red giant sheds much of its outer layers in a stellar wind. The white dwarf helps concentrate the wind along a thin equatorial plane. The white dwarf accretes some of this escaping gas forming a disk around the itself. Panel 3: When enough gas accumulates on the white dwarf's surface it explodes as a nova outburst. Most of the hot gas forms a pair of expanding bubbles above and below the equatorial disk. Panel 4: A few thousand years after the bubbles expand into space, the white dwarf goes through another nova outburst and makes another pair of bubbles, which form a distinctive hourglass shape.

Fuel containment, lightning protection and damage tolerance in large composite primary aircraft structures

NASA Technical Reports Server (NTRS)

Griffin, Charles F.; James, Arthur M.

1985-01-01

The damage-tolerance characteristics of high strain-to-failure graphite fibers and toughened resins were evaluated. Test results show that conventional fuel tank sealing techniques are applicable to composite structures. Techniques were developed to prevent fuel leaks due to low-energy impact damage. For wing panels subjected to swept stroke lightning strikes, a surface protection of graphite/aluminum wire fabric and a fastener treatment proved effective in eliminating internal sparking and reducing structural damage. The technology features developed were incorporated and demonstrated in a test panel designed to meet the strength, stiffness, and damage tolerance requirements of a large commercial transport aircraft. The panel test results exceeded design requirements for all test conditions. Wing surfaces constructed with composites offer large weight savings if design allowable strains for compression can be increased from current levels.

Vibration Response Predictions for Heavy Panel Mounted Components from Panel Acreage Environment Specifications

NASA Technical Reports Server (NTRS)

Harrison, Phillip; Frady, Greg; Duvall, Lowery; Fulcher, Clay; LaVerde, Bruce

2010-01-01

The development of new launch vehicles in the Aerospace industry often relies on response measurements taken from previously developed vehicles during various stages of liftoff and ascent, and from wind tunnel models. These measurements include sound pressure levels, dynamic pressures in turbulent boundary layers and accelerations. Rigorous statistical scaling methods are applied to the data to derive new environments and estimate the performance of new skin panel structures. Scaling methods have proven to be reliable, particularly for designs similar to the vehicles used as the basis for scaling, and especially in regions of smooth acreage without exterior protuberances or heavy components mounted to the panel. To account for response attenuation of a panel-mounted component due to its apparent mass at higher frequencies, the vibroacoustics engineer often reduces the acreage vibration according to a weight ratio first suggested by Barrett. The accuracy of the reduction is reduced with increased weight of the panel-mounted component, and does not account for low-frequency amplification of the component/panel response as a system. A method is proposed that combines acreage vibration from scaling methods with finite element analysis to account for the frequency-dependent dynamics of heavy panel-mounted components. Since the acreage and mass-loaded skins respond to the same dynamic input pressure, such pressure may be eliminated in favor of a frequency-dependent scaling function applied to the acreage vibration to predict the mass-loaded panel response. The scaling function replaces the Barrett weight ratio, and contains all of the dynamic character of the loaded and unloaded skin panels. The solution simplifies for spatially uncorrelated and fully correlated input pressures. Since the prediction uses finite element models of the loaded and unloaded skins, a rich suite of response data are available to the design engineer, including interface forces, stress and strain, as well as acceleration and displacement. An extension of the method is also developed to incorporate the effect of a local protuberance near a heavy component. Acreage environments from traditional scaling methods with and without protuberance effects serve as the basis for the extension. Authors:

Analysis of the Effect of Surface Modification on Polyimide Composites Coated with Erosion Resistant Materials

NASA Technical Reports Server (NTRS)

Ndalama, Tchinga; Hirschfeld, Deidre; Sutter, James K. (Technical Monitor)

2003-01-01

The aim of this research is to enhance performance of composite coatings through modification of graphite-reinforced polyimide composite surfaces prior to metal bond coat/ hard topcoat application for use in the erosive and/or oxidative environments of advanced engines. Graphite reinforced polyimide composites, PMR-15 and PMR-II-50, formed by sheet molding and pre-pregging will be surface treated, overlaid with a bond coat and then coated with WC-Co. The surface treatment will include cleaning, RF plasma or ultraviolet light- ozone etching, and deposition of SiO(x) groups. These surface treatments will be studied in order to investigate and improve adhesion and oxidation resistance. The following panels were provided by NASA-Glenn Research Center(NASA-GRC): Eight compression molded PMR-II-50; 6 x 6 x 0.125 in. Two vacuum-bagged PMR-II-50; 12 x 12 x 0.125 in. Eight compression molded PMR-15; 6 x 6 x 0.125 in. One vacuum-bagged PMR-15; 12 x 12 x 0.125 in. All panels were made using a 12 x 12 in. T650-35 8HS (3K-tow) graphite fabric. A diamond-wafering blade, with deionized water as a cutting fluid, was used to cut PMR-II-50 and PMR-15 panels into 1 x 1 in. pieces for surface tests. The panel edges exhibiting delamination were used for the preliminary surface preparation tests as these would be unsuitable for strength and erosion testing. PMR-15 neat resin samples were also provided by NASA GRC. Surface profiles of the as-received samples were determined using a Dektak III Surface profile measuring system. Two samples of compression molded PMR-II-50 and PMR-15, vacuum-bagged PMR-II-50 and PMR-15 were randomly chosen for surface profile measurement according to ANSI/ASME B46.1. Prior to each measurement, the samples were blasted with compressed air to remove any artifacts. Five 10 mm-long scans were made on each sample. The short and long wavelength cutoff filter values were set at 100 and 1000 m, diamond stylus radius was 12.5 microns. Table 1 is a summary of the arithmetic average roughness (Ra) and waviness (Wa) for the composite surfaces.

Moderately reverberant learning ultrasonic pinch panel.

PubMed

Nikolovski, Jean-Pierre

2013-10-01

Tactile sensing is widely used in human-computer interfaces. However, mechanical integration of touch technologies is often perceived as difficult by engineers because it often limits the freedom of style or form factor requested by designers. Recent work in active ultrasonic touch technologies has made it possible to transform thin glass plates, metallic sheets, or plastic shells into interactive surfaces. The method is based on a learning process of touch-induced, amplitude-disturbed diffraction patterns. This paper proposes, first, an evolution in the design with multiple dipole transducers that improves touch sensitivity or maximum panel size by a factor of ten, and improves robustness and usability in moderately reverberant panels, and second, defines a set of acoustic variables in the signal processing for the evaluation of sensitivity and radiating features. For proof of concept purposes, the design and process are applied to 3.2- and 6-mm-thick glass plates with variable damping conditions. Transducers are bonded to only one short side of the rectangular substrates. Measurements show that the highly sensitive free lateral sides are perfectly adapted for pinch-touch and pinch-slide interactions. The advantage of relative versus absolute touch disturbance measurement is discussed, together with tolerance to abutting contaminants.

Thermal neutron shield and method of manufacture

DOEpatents

Metzger, Bert Clayton; Brindza, Paul Daniel

2014-03-04

A thermal neutron shield comprising boron shielding panels with a high percentage of the element Boron. The panel is least 46% Boron by weight which maximizes the effectiveness of the shielding against thermal neutrons. The accompanying method discloses the manufacture of boron shielding panels which includes enriching the pre-cursor mixture with varying grit sizes of Boron Carbide.

Concealed hinge permits flush mounting of doors and hatches

NASA Technical Reports Server (NTRS)

Holman, E. V.

1966-01-01

Hinge assembly permits flush mounting of doors and hatches of considerable thickness so that the axis of instant rotation, produced by the hinge, lies outside the panel surface and beyond the perimeter adjacent to the hinge. In operation, motion of the assembly is initially parallel, changing to angular after clearing the panel perimeter.

Automatic Color Sorting System for Hardwood Edge-Glued Panel Parts

Treesearch

Richard W. Conners; D.Earl Kline; Philip A. Araman

1996-01-01

The color sorting of edge-glued panel parts is becoming more important in the manufacture of hardwood products. Consumers, while admiring the natural appearance of hardwoods, do not like excessive color variation across product surfaces. Color uniformity is particularly important today because of the popularity of lightly stained products. Unfortunately, color sorting...

F-16XL Ship #2 wing glove close-up, laser cut holes, with dime for scale

NASA Technical Reports Server (NTRS)

1995-01-01

This June 1995 photograph of a test panel similiar to the one attached to the surface of an F-16XL research aircraft's left wing at NASA's Dryden Flight Research Center, Edwards, California, shows the size of the more than 10 million laser-cut holes in the panel, called a glove, as compared with a dime. Below the titanium panel into which holes are cut is a suction system linked to a compressor. During research flights with the modified, delta-winged F-16XL, the suction system pulled a small part of the boundary layer of air through the glove's porous surface to expand the extent of smooth (laminar) flow. Researchers believe that laminar flow conditions can reduce aerodynamic drag (friction) and contribute to reduced operating costs by improving fuel consumption and lowering aircraft weight. This Supersonic Laminar Flow Control (SLFC) experiment represents a collaborative effort between NASA and aerospace industry (specifically Boeing, Rockwell, and McDonnell Douglas), with Boeing assembling the panel and McDonnell Douglas designing the suction system.

A visual analytical approach to rock art panel condition assessment

NASA Astrophysics Data System (ADS)

Vogt, Brandon J.

Rock art is a term for pecked, scratched, or painted symbols found on rock surfaces, most typically joint faces called rock art panels. Because rock art exists on rock at the atmosphere interface, it is highly susceptible to the destructive processes of weathering. Thus, rock weathering scientists, including those that study both natural and cultural surfaces, play a key role towards understanding rock art longevity. The mapping of weathering forms on rock art panels serves as a basis from which to assess overall panel instability. This work examines fissures, case hardened surfaces, crumbly disintegration, and lichen. Knowledge of instability, as measured through these and other weathering forms, provides integral information to land managers and archaeological conservators required to prioritize panels for remedial action. The work is divided into five chapters, three of which are going to be submitted as a peer-reviewed journal manuscript. The second chapter, written as a manuscript for International Newsletter on Rock Art, describes a specific set of criteria that lead to the development of a mapping tool for weathering forms, called 'mapping weathering forms in three dimensions' (MapWeF). The third chapter, written as a manuscript for Remote Sensing of Environment, presents the methodology used to develop MapWeF. The chapter incorporates terrestrial laser scanning, a geographic information system (GIS), geovisualization, image analysis, and exploratory spatial data analysis (ESDA) to identify, map, and quantify weathering features known to cause instability on rock art panels. The methodology implemented in the third chapter satisfies the criteria described in Chapter Two. In the fourth chapter, prepared as a manuscript for Geomorphology, MapWeF is applied to a site management case study, focusing on a region---southeastern Colorado---with notoriously weak and endangered sandstone rock art panels. The final conclusions chapter describes contributions of the work to GIScience and rock weathering, and discusses how MapWeF, as a diagnostic tool, fits into a larger national vision by linking existing rock art stability characterizations to cultural resource management-related conservation action.

Application of Differential InSAR to Mining

NASA Astrophysics Data System (ADS)

Eneva, M.; Baker, E.; Xu, H.

2001-12-01

In a NASA funded project we are applying differential InSAR to measure surface deformation associated with mining at depth. Surface displacement can be caused by rockbursts associated with mine collapse or mining-induced stress released on nearby tectonic features. The latter type of rockbursts are similar to tectonic earthquakes, but generally occur at shallower depths than non-induced events of similar size. Thus significant co-seismic surface changes may accompany them. In addition, subsidence of a more gradual type may result from ongoing soft-rock (e.g., coal, potash, salt) mining. While such subsidence can accidentally occur above abandoned mines, it is most often planned as part of the ongoing ore extraction, especially in so-called long-wall mining. Predicting the amount and spatial extent of this subsidence is an aspect of mining engineering. It is important to compare these predictions with measurements of the actual deformation. Although mines use leveling and GPS measurements to monitor subsidence, these are generally performed with much smaller frequency (e.g., annually) and lower spatial resolution than repeat-pass differential InSAR can provide. We are using ERS-1/2 raw SAR data provided by ESA and Eurimage, and the Gamma software for their processing. At present we are focused on the processing and modeling of data from two representative sites. By the end of the project we will have analyzed several more sites of subsidence and M>4.5 rockbursts. As an example of mining subsidence, we are currently analyzing data from the site of a coal mine in Colorado (USA), operating in a relatively flat and arid area. Numerous adjacent long-wall panels of extraction are used, some exceeding 5 km in length. A 600 to 750-m length of panel may be extracted per month, with a maximum subsidence of 1.5 to 1.8 m expected over each panel. The surface deformation can be monitored especially well during the summers of 1995 and 1996, when nine good-quality ERS-1/2 SAR scenes were gathered. Two of these scenes form a tandem pair to be used for topography. We are also making use of a 30-m DEM from USGS, maps of extraction panels, leveling data and microearthquake locations. As an example of rockbursts, we are presently analyzing ERS-2 SAR data from the site of a M5.1 rockburst that occurred on April 22, 1999, in the gold fields of Welkom, South Africa. The event was induced on a fault transecting the mine and had a normal mechanism. Only two good-quality SAR scenes are available from this site, spanning about a year including the event. Thus the topography effect cannot be removed using interferometry. However, since flat surface and urban environment characterize this site, a clear fringe pattern is observed, apparently associated with the rockburst. This pattern suggests up to 9-cm subsidence. Its center is within 5 km from the seismically determined event location. Thus this rockburst represents an example of the capabilities of InSAR to provide ground truth locations for moderate shallow earthquakes. To model the seismic source, we are using the RNGCHN software (Feigl and Dupré, 1999) based on analytic solutions for a homogeneous half-space. In order to model deformation in realistically complex crust, including layered structure and lateral heterogeneities, we are also developing a 3D finite-difference method of estimating deformation in a volume due to displacement on a fault surface. This method will be also used for the modeling of mining subsidence.

Direct metal transfer printing on flexible substrate for fabricating optics functional devices

NASA Astrophysics Data System (ADS)

Jiang, Yingjie; Zhou, Xiaohong; Zhang, Feng; Shi, Zhenwu; Chen, Linsen; Peng, Changsi

2015-11-01

New functional materials and devices based on metal patterns can be widely used in many new and expanding industries,such as flat panel displays, alternative energy,sensors and so on. In this paper, we introduce a new transfer printing method for fabricating metal optics functional devices. This method can directly transfer a metal pattern from a polyethylene terephthalate (PET)supported UV or polydimethylsiloxane (PDMS) pattern to another PET substrate. Purely taking advantage of the anaerobic UV curing adhesive (a-UV) on PET substrate, metal film can be easily peeled off from micro/nano-structured surface. As a result, metal film on the protrusion can be selectively transferred onto the target substrate, to make it the metal functional surface. But which on the bottom can not be transferred. This method provides low cost fabrication of metal thin film devices by avoiding high cost lithography process. Compared with conventional approach, this method can get more smooth rough edges and has wider tolerance range for the original master mold. Future developments and potential applications of this metal transfer method will be addressed.

Analyzing panel acoustic contributions toward the sound field inside the passenger compartment of a full-size automobile.

PubMed

Wu, Sean F; Moondra, Manmohan; Beniwal, Ravi

2015-04-01

The Helmholtz equation least squares (HELS)-based nearfield acoustical holography (NAH) is utilized to analyze panel acoustic contributions toward the acoustic field inside the interior region of an automobile. Specifically, the acoustic power flows from individual panels are reconstructed, and relative contributions to sound pressure level and spectrum at any point of interest are calculated. Results demonstrate that by correlating the acoustic power flows from individual panels to the field acoustic pressure, one can correctly locate the panel allowing the most acoustic energy transmission into the vehicle interior. The panel on which the surface acoustic pressure amplitude is the highest should not be used as indicative of the panel responsible for the sound field in the vehicle passenger compartment. Another significant advantage of this HELS-based NAH is that measurements of the input data only need to be taken once by using a conformal array of microphones in the near field, and ranking of panel acoustic contributions to any field point can be readily performed. The transfer functions between individual panels of any vibrating structure to the acoustic pressure anywhere in space are calculated not measured, thus significantly reducing the time and effort involved in panel acoustic contributions analyses.

Heart Rhythm Monitoring in the Constellation Lunar and Launch/Landing EVA Suit: Recommendations from an Expert Panel

NASA Technical Reports Server (NTRS)

Scheuring, Richard A.; Hamilton, Doug; Jones, Jeffrey A.; Alexander, David

2009-01-01

There are currently several physiological monitoring requirements for EVA in the Human-Systems Interface Requirements (HSIR) document. There are questions as to whether the capability to monitor heart rhythm in the lunar surface space suit is a necessary capability for lunar surface operations. Similarly, there are questions as to whether the capability to monitor heart rhythm during a cabin depressurization scenario in the launch/landing space suit is necessary. This presentation seeks to inform space medicine personnel of recommendations made by an expert panel of cardiovascular medicine specialists regarding in-suit ECG heart rhythm monitoring requirements during lunar surface operations. After a review of demographic information and clinical cases and panel discussion, the panel recommended that ECG monitoring capability as a clinical tool was not essential in the lunar space suit; ECG monitoring was not essential in the launch/landing space suit for contingency scenarios; the current hear rate monitoring capability requirement for both launch/landing and lunar space suits should be maintained; lunar vehicles should be required to have ECG monitoring capability with a minimum of 5-lead ECG for IVA medical assessments; and, exercise stress testing for astronaut selection and retention should be changed from the current 85% maximum heart rate limit to maximal, exhaustive 'symptom-limited' testing to maximize diagnostic utility as a screening tool for evaluating the functional capacity of astronauts and their cardiovascular health.

Ultra-low-density genotype panels for breed assignment of Angus and Hereford cattle.

PubMed

Judge, M M; Kelleher, M M; Kearney, J F; Sleator, R D; Berry, D P

2017-06-01

Angus and Hereford beef is marketed internationally for apparent superior meat quality attributes; DNA-based breed authenticity could be a useful instrument to ensure consumer confidence on premium meat products. The objective of this study was to develop an ultra-low-density genotype panel to accurately quantify the Angus and Hereford breed proportion in biological samples. Medium-density genotypes (13 306 single nucleotide polymorphisms (SNPs)) were available on 54 703 commercial and 4042 purebred animals. The breed proportion of the commercial animals was generated from the medium-density genotypes and this estimate was regarded as the gold-standard breed composition. Ten genotype panels (100 to 1000 SNPs) were developed from the medium-density genotypes; five methods were used to identify the most informative SNPs and these included the Delta statistic, the fixation (F st) statistic and an index of both. Breed assignment analyses were undertaken for each breed, panel density and SNP selection method separately with a programme to infer population structure using the entire 13 306 SNP panel (representing the gold-standard measure). Breed assignment was undertaken for all commercial animals (n=54 703), animals deemed to contain some proportion of Angus based on pedigree (n=5740) and animals deemed to contain some proportion of Hereford based on pedigree (n=5187). The predicted breed proportion of all animals from the lower density panels was then compared with the gold-standard breed prediction. Panel density, SNP selection method and breed all had a significant effect on the correlation of predicted and actual breed proportion. Regardless of breed, the Index method of SNP selection numerically (but not significantly) outperformed all other selection methods in accuracy (i.e. correlation and root mean square of prediction) when panel density was ⩾300 SNPs. The correlation between actual and predicted breed proportion increased as panel density increased. Using 300 SNPs (selected using the global index method), the correlation between predicted and actual breed proportion was 0.993 and 0.995 in the Angus and Hereford validation populations, respectively. When SNP panels optimised for breed prediction in one population were used to predict the breed proportion of a separate population, the correlation between predicted and actual breed proportion was 0.034 and 0.044 weaker in the Hereford and Angus populations, respectively (using the 300 SNP panel). It is necessary to include at least 300 to 400 SNPs (per breed) on genotype panels to accurately predict breed proportion from biological samples.

A Co-Precursor Approach Coupled with a Supercritical Modification Method for Constructing Highly Transparent and Superhydrophobic Polymethylsilsesquioxane Aerogels.

PubMed

Lei, Chaoshuai; Li, Junning; Sun, Chencheng; Yang, Hailong; Xia, Tao; Hu, Zijun; Zhang, Yue

2018-03-30

Polymethylsilsesquioxane (PMSQ) aerogels obtained from methyltrimethoxysilane (MTMS) are well-known high-performance porous materials. Highly transparent and hydrophobic PMSQ aerogel would play an important role in transparent vacuum insulation panels. Herein, the co-precursor approach and supercritical modification method were developed to prepare the PMSQ aerogels with high transparency and superhydrophobicity. Firstly, benefiting from the introduction of tetramethoxysilane (TMOS) in the precursor, the pore structure became more uniform and the particle size was decreased. As the TMOS content increased, the light transmittance increased gradually from 54.0% to 81.2%, whereas the contact angle of water droplet decreased from 141° to 99.9°, ascribed to the increase of hydroxyl groups on the skeleton surface. Hence, the supercritical modification method utilizing hexamethyldisilazane was also introduced to enhance the hydrophobic methyl groups on the aerogel's surface. As a result, the obtained aerogels revealed superhydrophobicity with a contact angle of 155°. Meanwhile, the developed surface modification method did not lead to any significant changes in the pore structure resulting in the superhydrophobic aerogel with a high transparency of 77.2%. The proposed co-precursor approach and supercritical modification method provide a new horizon in the fabrication of highly transparent and superhydrophobic PMSQ aerogels.

Test/semi-empirical analysis of a carbon/epoxy fabric stiffened panel

NASA Technical Reports Server (NTRS)

Spier, E. E.; Anderson, J. A.

1990-01-01

The purpose of this work-in-progress is to present a semi-empirical analysis method developed to predict the buckling and crippling loads of carbon/epoxy fabric blade stiffened panels in compression. This is a hand analysis method comprised of well known, accepted techniques, logical engineering judgements, and experimental data that results in conservative solutions. In order to verify this method, a stiffened panel was fabricated and tested. Both the best and analysis results are presented.

A new multi-domain method based on an analytical control surface for linear and second-order mean drift wave loads on floating bodies

NASA Astrophysics Data System (ADS)

Liang, Hui; Chen, Xiaobo

2017-10-01

A novel multi-domain method based on an analytical control surface is proposed by combining the use of free-surface Green function and Rankine source function. A cylindrical control surface is introduced to subdivide the fluid domain into external and internal domains. Unlike the traditional domain decomposition strategy or multi-block method, the control surface here is not panelized, on which the velocity potential and normal velocity components are analytically expressed as a series of base functions composed of Laguerre function in vertical coordinate and Fourier series in the circumference. Free-surface Green function is applied in the external domain, and the boundary integral equation is constructed on the control surface in the sense of Galerkin collocation via integrating test functions orthogonal to base functions over the control surface. The external solution gives rise to the so-called Dirichlet-to-Neumann [DN2] and Neumann-to-Dirichlet [ND2] relations on the control surface. Irregular frequencies, which are only dependent on the radius of the control surface, are present in the external solution, and they are removed by extending the boundary integral equation to the interior free surface (circular disc) on which the null normal derivative of potential is imposed, and the dipole distribution is expressed as Fourier-Bessel expansion on the disc. In the internal domain, where the Rankine source function is adopted, new boundary integral equations are formulated. The point collocation is imposed over the body surface and free surface, while the collocation of the Galerkin type is applied on the control surface. The present method is valid in the computation of both linear and second-order mean drift wave loads. Furthermore, the second-order mean drift force based on the middle-field formulation can be calculated analytically by using the coefficients of the Fourier-Laguerre expansion.

Flat Surface Damage Detection System (FSDDS)

NASA Technical Reports Server (NTRS)

Williams, Martha; Lewis, Mark; Gibson, Tracy; Lane, John; Medelius, Pedro; Snyder, Sarah; Ciarlariello, Dan; Parks, Steve; Carrejo, Danny; Rojdev, Kristina

2013-01-01

The Flat Surface Damage Detection system (FSDDS} is a sensory system that is capable of detecting impact damages to surfaces utilizing a novel sensor system. This system will provide the ability to monitor the integrity of an inflatable habitat during in situ system health monitoring. The system consists of three main custom designed subsystems: the multi-layer sensing panel, the embedded monitoring system, and the graphical user interface (GUI). The GUI LABVIEW software uses a custom developed damage detection algorithm to determine the damage location based on the sequence of broken sensing lines. It estimates the damage size, the maximum depth, and plots the damage location on a graph. Successfully demonstrated as a stand alone technology during 2011 D-RATS. Software modification also allowed for communication with HDU avionics crew display which was demonstrated remotely (KSC to JSC} during 2012 integration testing. Integrated FSDDS system and stand alone multi-panel systems were demonstrated remotely and at JSC, Mission Operations Test using Space Network Research Federation (SNRF} network in 2012. FY13, FSDDS multi-panel integration with JSC and SNRF network Technology can allow for integration with other complementary damage detection systems.

On Laminar to Turbulent Transition of Arc-Jet Flow in the NASA Ames Panel Test Facility

NASA Technical Reports Server (NTRS)

Gokcen, Tahir; Alunni, Antonella I.

2012-01-01

This paper provides experimental evidence and supporting computational analysis to characterize the laminar to turbulent flow transition in a high enthalpy arc-jet facility at NASA Ames Research Center. The arc-jet test data obtained in the 20 MW Panel Test Facility include measurements of surface pressure and heat flux on a water-cooled calibration plate, and measurements of surface temperature on a reaction-cured glass coated tile plate. Computational fluid dynamics simulations are performed to characterize the arc-jet test environment and estimate its parameters consistent with the facility and calibration measurements. The present analysis comprises simulations of the nonequilibrium flowfield in the facility nozzle, test box, and flowfield over test articles. Both laminar and turbulent simulations are performed, and the computed results are compared with the experimental measurements, including Stanton number dependence on Reynolds number. Comparisons of computed and measured surface heat fluxes (and temperatures), along with the accompanying analysis, confirm that that the boundary layer in the Panel Test Facility flow is transitional at certain archeater conditions.

Experimental results on plasma interactions with large surfaces at high voltages

NASA Technical Reports Server (NTRS)

Grier, N. T.

1980-01-01

Multikilowatt power levels for future payloads can be more efficiently generated using solar arrays operating in the kilovolt range. This implies that large areas of the array at high operating voltages will be exposed to the space plasma environment. The resulting interactions of these high voltage surfaces with space plasma environments can seriously impact the performance of the satellite system. The plasma-surface interaction phenomena were studied in tests performed in two separate vacuum chambers, a 4.6 m diameter by 19.2 long chamber and a 20 m diameter by 27.4 m long chamber. The generated plasma density was approximately 1x10 to the 4th power/cu cm. Ten solar array panels, each with areas of 1400 sq cm were used in the tests. Nine of the solar panels were tested as a composite unit in the form of a 3x3 solar panel matrix. The results from all the tests confirmed small sample tests results: insulators were found to enhance the plasma coupling current for high positive bias and arcing was found to occur at high negative bias.

Computer prediction of three-dimensional potential flow fields in which aircraft propellers operate. M.S. Thesis

NASA Technical Reports Server (NTRS)

Jumper, S. J.

1982-01-01

A computer program was developed to calculate the three dimensional, steady, incompressible, inviscid, irrotational flow field at the propeller plane (propeller removed) located upstream of an arbitrary airframe geometry. The program uses a horseshoe vortex of known strength to model the wing. All other airframe surfaces are modeled by a network source panels of unknown strength which is exposed to a uniform free stream and the wing-induced velocity field. By satisfying boundary conditions on each panel (the Neumann problem), relaxed boundary conditions being used on certain panels to simulate inlet inflow, the source strengths are determined. From the known source and wing vortex strengths, the resulting velocity fields on the airframe surface and at the propeller plane are obtained. All program equations are derived in detail, and a brief description of the program structure is presented. A user's manual which fully documents the program is cited. Computer predictions of the flow on the surface of a sphere and at a propeller plane upstream of the sphere are compared with the exact mathematical solutions. Agreement is good, and correct program operation is verified.

Improvement of illumination uniformity for LED flat panel light by using micro-secondary lens array.

PubMed

Lee, Hsiao-Wen; Lin, Bor-Shyh

2012-11-05

LED flat panel light is an innovative lighting product in recent years. However, current flat panel light products still contain some drawbacks, such as narrow lighting areas and hot spots. In this study, a micro-secondary lens array technique was proposed and applied for the design of the light guide surface to improve the illumination uniformity. By using the micro-secondary lens array, the candela distribution of the LED flat panel light can be adjusted to similar to batwing distribution to improve the illumination uniformity. The experimental results show that the enhancement of the floor illumination uniformity is about 61%, and that of the wall illumination uniformity is about 20.5%.

Robust estimation procedure in panel data model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shariff, Nurul Sima Mohamad; Hamzah, Nor Aishah

2014-06-19

The panel data modeling has received a great attention in econometric research recently. This is due to the availability of data sources and the interest to study cross sections of individuals observed over time. However, the problems may arise in modeling the panel in the presence of cross sectional dependence and outliers. Even though there are few methods that take into consideration the presence of cross sectional dependence in the panel, the methods may provide inconsistent parameter estimates and inferences when outliers occur in the panel. As such, an alternative method that is robust to outliers and cross sectional dependencemore » is introduced in this paper. The properties and construction of the confidence interval for the parameter estimates are also considered in this paper. The robustness of the procedure is investigated and comparisons are made to the existing method via simulation studies. Our results have shown that robust approach is able to produce an accurate and reliable parameter estimates under the condition considered.« less

Experimental study of efficiency of solar panel by phase change material cooling

NASA Astrophysics Data System (ADS)

Wei, Nicholas Tan Jian; Nan, Wong Jian; Guiping, Cheng

2017-07-01

The dependence of efficiency of photovoltaic panels on their temperature during operation is a major concern for developers and users. In this paper, a phase change material (PCM) cooling system was designed for a 60W mono-crystalline solar panel. Tealights candle was selected as the cooling medium. The solar irradiance was recorded using Kipp & Zonen CMP3 pyranometer and Meteon data logger. Temperature distribution on the surface of solar panel, output voltage and output current of solar panel were measured. The average irradiance throughout data collection was found to be 705W/m2 and highest irradiance was 1100 W/m2. The average solar panel temperature was 43.6°C and a maximum temperature of 53°C was at the center of solar panel. Results showed that average power output and efficiency of the solar panel were 44.4W and 15%, respectively. It was found that the higher the solar irradiance, the lower the efficiency of solar panel and the higher the temperature and power output of solar panel. This is due to the fact that high irradiance results in high power input and high solar panel temperature. But high PV panel temperature reduces its power output. Therefore, the increase of power input outweighs that of power output, which leads to the decrease of efficiency of solar panel with the increase of solar irradiance. Compared with solar panel without cooling, the power output and efficiency of solar panel did not increase with PCM cooling. It indicates that Tealights candle as PCM cooling is not efficient in improving the efficiency of solar panel in this study.

Variable-intercept panel model for deformation zoning of a super-high arch dam.

PubMed

Shi, Zhongwen; Gu, Chongshi; Qin, Dong

2016-01-01

This study determines dam deformation similarity indexes based on an analysis of deformation zoning features and panel data clustering theory, with comprehensive consideration to the actual deformation law of super-high arch dams and the spatial-temporal features of dam deformation. Measurement methods of these indexes are studied. Based on the established deformation similarity criteria, the principle used to determine the number of dam deformation zones is constructed through entropy weight method. This study proposes the deformation zoning method for super-high arch dams and the implementation steps, analyzes the effect of special influencing factors of different dam zones on the deformation, introduces dummy variables that represent the special effect of dam deformation, and establishes a variable-intercept panel model for deformation zoning of super-high arch dams. Based on different patterns of the special effect in the variable-intercept panel model, two panel analysis models were established to monitor fixed and random effects of dam deformation. Hausman test method of model selection and model effectiveness assessment method are discussed. Finally, the effectiveness of established models is verified through a case study.

Building with stress-skin panels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bliss, S.

1983-10-01

A promising new technique for constructing homes that employs stress-skin panels is described. In this method, the insulation, drywall, and sheathing are hung in a single panel. The panels are made in 4 x 8 ft. and up and are either laminated or foamed in place. Both processes require strict manufacturing controls.

Parametric analysis of swept-wing geometry with sheared wing tips

NASA Technical Reports Server (NTRS)

Fremaux, C. M.; Vijgen, P. M. H. W.; Van Dam, C. P.

1990-01-01

A computational parameter study is presented of potential reductions in induced drag and increases in lateral-directional stability due to sheared wing tips attached to an untwisted wing of moderate sweep and aspect ratio. Sheared tips are swept and tapered wing-tip devices mounted in the plane of the wing. The induced-drag results are obtained using an inviscid, incompressible surface-panel method that models the nonlinear effects due to the deflected and rolled-up wake behind the lifting surface. The induced-drag results with planar sheared tips are compared to straight-tapered tip extensions and nonplanar winglet geometries. The lateral-directional static-stability characteristics of the wing with sheared tips are estimated using a quasi-vortex-lattice method. For certain combinations of sheared-tip sweep and taper, both the induced efficiency of the wing and the relevant static-stability derivatives are predicted to increase compared to the wing with a straight-tapered tip modification.

Comparison of real-time PCR methods for the detection of Naegleria fowleri in surface water and sediment.

PubMed

Streby, Ashleigh; Mull, Bonnie J; Levy, Karen; Hill, Vincent R

2015-05-01

Naegleria fowleri is a thermophilic free-living ameba found in freshwater environments worldwide. It is the cause of a rare but potentially fatal disease in humans known as primary amebic meningoencephalitis. Established N. fowleri detection methods rely on conventional culture techniques and morphological examination followed by molecular testing. Multiple alternative real-time PCR assays have been published for rapid detection of Naegleria spp. and N. fowleri. Foursuch assays were evaluated for the detection of N. fowleri from surface water and sediment. The assays were compared for thermodynamic stability, analytical sensitivity and specificity, detection limits, humic acid inhibition effects, and performance with seeded environmental matrices. Twenty-one ameba isolates were included in the DNA panel used for analytical sensitivity and specificity analyses. N. fowleri genotypes I and III were used for method performance testing. Two of the real-time PCR assays were determined to yield similar performance data for specificity and sensitivity for detecting N. fowleri in environmental matrices.

Comparison of real-time PCR methods for the detection of Naegleria fowleri in surface water and sediment

PubMed Central

Streby, Ashleigh; Mull, Bonnie J.; Levy, Karen

2015-01-01

Naegleria fowleri is a thermophilic free-living ameba found in freshwater environments worldwide. It is the cause of a rare but potentially fatal disease in humans known as primary amebic meningoencephalitis. Established N. fowleri detection methods rely on conventional culture techniques and morphological examination followed by molecular testing. Multiple alternative real-time PCR assays have been published for rapid detection of Naegleria spp. and N. fowleri. Four such assays were evaluated for the detection of N. fowleri from surface water and sediment. The assays were compared for thermodynamic stability, analytical sensitivity and specificity, detection limits, humic acid inhibition effects, and performance with seeded environmental matrices. Twenty-one ameba isolates were included in the DNA panel used for analytical sensitivity and specificity analyses. N. fowleri genotypes I and III were used for method performance testing. Two of the real-time PCR assays were determined to yield similar performance data for specificity and sensitivity for detecting N. fowleri in environmental matrices. PMID:25855343

Inverse design of a proper number, shapes, sizes, and locations of coolant flow passages

NASA Technical Reports Server (NTRS)

Dulikravich, George S.

1992-01-01

During the past several years we have developed an inverse method that allows a thermal cooling system designer to determine proper sizes, shapes, and locations of coolant passages (holes) in, say, an internally cooled turbine blade, a scram jet strut, a rocket chamber wall, etc. Using this method the designer can enforce a desired heat flux distribution on the hot outer surface of the object, while simultaneously enforcing desired temperature distributions on the same hot outer surface as well as on the cooled interior surfaces of each of the coolant passages. This constitutes an over-specified problem which is solved by allowing the number, sizes, locations and shapes of the holes to adjust iteratively until the final internally cooled configuration satisfies the over-specified surface thermal conditions and the governing equation for the steady temperature field. The problem is solved by minimizing an error function expressing the difference between the specified and the computed hot surface heat fluxes. The temperature field analysis was performed using our highly accurate boundary integral element code with linearly varying temperature along straight surface panels. Examples of the inverse design applied to internally cooled turbine blades and scram jet struts (coated and non-coated) having circular and non-circular coolant flow passages will be shown.

An evaluation of random analysis methods for the determination of panel damping

NASA Technical Reports Server (NTRS)

Bhat, W. V.; Wilby, J. F.

1972-01-01

An analysis is made of steady-state and non-steady-state methods for the measurement of panel damping. Particular emphasis is placed on the use of random process techniques in conjunction with digital data reduction methods. The steady-state methods considered use the response power spectral density, response autocorrelation, excitation-response crosspower spectral density, or single-sided Fourier transform (SSFT) of the response autocorrelation function. Non-steady-state methods are associated mainly with the use of rapid frequency sweep excitation. Problems associated with the practical application of each method are evaluated with specific reference to the case of a panel exposed to a turbulent airflow, and two methods, the power spectral density and the single-sided Fourier transform methods, are selected as being the most suitable. These two methods are demonstrated experimentally, and it is shown that the power spectral density method is satisfactory under most conditions, provided that appropriate corrections are applied to account for filter bandwidth and background noise errors. Thus, the response power spectral density method is recommended for the measurement of the damping of panels exposed to a moving airflow.

Mechanical Strength and Broadband Transparency Improvement of Glass Wafers via Surface Nanostructures.

PubMed

Kumar, Amarendra; Kashyap, Kunal; Hou, Max T; Yeh, J Andrew

2016-06-17

In this study, we mechanically strengthened a borosilicate glass wafer by doubling its bending strength and simultaneously enhancing its transparency using surface nanostructures for different applications including sensors, displays and panels. A fabrication method that combines dry and wet etching is used for surface nanostructure fabrication. Specifically, we improved the bending strength of plain borosilicate glass by 96% using these surface nanostructures on both sides. Besides bending strength improvement, a limited optical transmittance enhancement of 3% was also observed in the visible light wavelength region (400-800 nm). Both strength and transparency were improved by using surface nanostructures of 500 nm depth on both sides of the borosilicate glass without affecting its bulk properties or the glass manufacturing process. Moreover, we observed comparatively smaller fragments during the breaking of the nanostructured glass, which is indicative of strengthening. The range for the nanostructure depth is defined for different applications with which improvements of the strength and transparency of borosilicate glass substrate are obtained.

Mechanical Strength and Broadband Transparency Improvement of Glass Wafers via Surface Nanostructures

PubMed Central

Kumar, Amarendra; Kashyap, Kunal; Hou, Max T.; Yeh, J. Andrew

2016-01-01

In this study, we mechanically strengthened a borosilicate glass wafer by doubling its bending strength and simultaneously enhancing its transparency using surface nanostructures for different applications including sensors, displays and panels. A fabrication method that combines dry and wet etching is used for surface nanostructure fabrication. Specifically, we improved the bending strength of plain borosilicate glass by 96% using these surface nanostructures on both sides. Besides bending strength improvement, a limited optical transmittance enhancement of 3% was also observed in the visible light wavelength region (400–800 nm). Both strength and transparency were improved by using surface nanostructures of 500 nm depth on both sides of the borosilicate glass without affecting its bulk properties or the glass manufacturing process. Moreover, we observed comparatively smaller fragments during the breaking of the nanostructured glass, which is indicative of strengthening. The range for the nanostructure depth is defined for different applications with which improvements of the strength and transparency of borosilicate glass substrate are obtained. PMID:27322276

49 CFR 571.219 - Standard No. 219; Windshield zone intrusion.

Code of Federal Regulations, 2010 CFR

2010-10-01

... contact with the windshield, shall penetrate the protected zone template, affixed according to S6, to a... simultaneously contacts the inner surface of the windshield glazing and the surface of the instrument panel... surface of the windshield. (c) The locus of lines forming a 45° angle with the outer surface of the...

Light extraction block with curved surface

DOEpatents

Levermore, Peter; Krall, Emory; Silvernail, Jeffrey; Rajan, Kamala; Brown, Julia J.

2016-03-22

Light extraction blocks, and OLED lighting panels using light extraction blocks, are described, in which the light extraction blocks include various curved shapes that provide improved light extraction properties compared to parallel emissive surface, and a thinner form factor and better light extraction than a hemisphere. Lighting systems described herein may include a light source with an OLED panel. A light extraction block with a three-dimensional light emitting surface may be optically coupled to the light source. The three-dimensional light emitting surface of the block may includes a substantially curved surface, with further characteristics related to the curvature of the surface at given points. A first radius of curvature corresponding to a maximum principal curvature k.sub.1 at a point p on the substantially curved surface may be greater than a maximum height of the light extraction block. A maximum height of the light extraction block may be less than 50% of a maximum width of the light extraction block. Surfaces with cross sections made up of line segments and inflection points may also be fit to approximated curves for calculating the radius of curvature.

Development of Statistical Process Control Methodology for an Environmentally Compliant Surface Cleaning Process in a Bonding Laboratory

NASA Technical Reports Server (NTRS)

Hutchens, Dale E.; Doan, Patrick A.; Boothe, Richard E.

1997-01-01

Bonding labs at both MSFC and the northern Utah production plant prepare bond test specimens which simulate or witness the production of NASA's Reusable Solid Rocket Motor (RSRM). The current process for preparing the bonding surfaces employs 1,1,1-trichloroethane vapor degreasing, which simulates the current RSRM process. Government regulations (e.g., the 1990 Amendments to the Clean Air Act) have mandated a production phase-out of a number of ozone depleting compounds (ODC) including 1,1,1-trichloroethane. In order to comply with these regulations, the RSRM Program is qualifying a spray-in-air (SIA) precision cleaning process using Brulin 1990, an aqueous blend of surfactants. Accordingly, surface preparation prior to bonding process simulation test specimens must reflect the new production cleaning process. The Bonding Lab Statistical Process Control (SPC) program monitors the progress of the lab and its capabilities, as well as certifies the bonding technicians, by periodically preparing D6AC steel tensile adhesion panels with EA-91 3NA epoxy adhesive using a standardized process. SPC methods are then used to ensure the process is statistically in control, thus producing reliable data for bonding studies, and identify any problems which might develop. Since the specimen cleaning process is being changed, new SPC limits must be established. This report summarizes side-by-side testing of D6AC steel tensile adhesion witness panels and tapered double cantilevered beams (TDCBs) using both the current baseline vapor degreasing process and a lab-scale spray-in-air process. A Proceco 26 inches Typhoon dishwasher cleaned both tensile adhesion witness panels and TDCBs in a process which simulates the new production process. The tests were performed six times during 1995, subsequent statistical analysis of the data established new upper control limits (UCL) and lower control limits (LCL). The data also demonstrated that the new process was equivalent to the vapor degreasing process.

Evaluation of the operation efficiency of solar panels in winter

NASA Astrophysics Data System (ADS)

Burakova, A. D.; Burakova, L. N.; Anisimov, I. A.; Burakova, O. D.

2017-06-01

The article deals with the issue of increasing the comfort and safety of life in cities by applying an alternative energy source for power supply of transport infrastructure facilities. Due to the peculiarity of the Russian Federation territory location, most cities are characterized by a long winter period, which makes it necessary to consider the features of using solar panels under these conditions. It has been established that the efficiency of solar panels depends on their type and location, the presence of snow cover on their surface, and the ambient air temperature. It has been revealed that flexible solar panels have some advantages that determine their ability to be used for power supply of transport infrastructure facilities. In the paper, the optimum angle of inclination of rigid solar panels in the winter period of the year is determined.

Citywide Impacts of Cool Roof and Rooftop Solar Photovoltaic Deployment on Near-Surface Air Temperature and Cooling Energy Demand

NASA Astrophysics Data System (ADS)

Salamanca, F.; Georgescu, M.; Mahalov, A.; Moustaoui, M.; Martilli, A.

2016-10-01

Assessment of mitigation strategies that combat global warming, urban heat islands (UHIs), and urban energy demand can be crucial for urban planners and energy providers, especially for hot, semi-arid urban environments where summertime cooling demands are excessive. Within this context, summertime regional impacts of cool roof and rooftop solar photovoltaic deployment on near-surface air temperature and cooling energy demand are examined for the two major USA cities of Arizona: Phoenix and Tucson. A detailed physics-based parametrization of solar photovoltaic panels is developed and implemented in a multilayer building energy model that is fully coupled to the Weather Research and Forecasting mesoscale numerical model. We conduct a suite of sensitivity experiments (with different coverage rates of cool roof and rooftop solar photovoltaic deployment) for a 10-day clear-sky extreme heat period over the Phoenix and Tucson metropolitan areas at high spatial resolution (1-km horizontal grid spacing). Results show that deployment of cool roofs and rooftop solar photovoltaic panels reduce near-surface air temperature across the diurnal cycle and decrease daily citywide cooling energy demand. During the day, cool roofs are more effective at cooling than rooftop solar photovoltaic systems, but during the night, solar panels are more efficient at reducing the UHI effect. For the maximum coverage rate deployment, cool roofs reduced daily citywide cooling energy demand by 13-14 %, while rooftop solar photovoltaic panels by 8-11 % (without considering the additional savings derived from their electricity production). The results presented here demonstrate that deployment of both roofing technologies have multiple benefits for the urban environment, while solar photovoltaic panels add additional value because they reduce the dependence on fossil fuel consumption for electricity generation.

The Characteristics of Fatigue Damage in the Fuselage Riveted Lap Splice Joint

NASA Technical Reports Server (NTRS)

Piascik, Robert S.; Willard, Scott A.

1997-01-01

An extensive data base has been developed to form the physical basis for new analytical methodology to predict the onset of widespread fatigue damage in the fuselage lap splice joint. The results of detailed destructive examinations have been cataloged to describe the physical nature of MSD in the lap splice joint. ne catalog includes a detailed description, e.g., crack initiation, growth rates, size, location, and fracture morphology, of fatigue damage in the fuselage lap splice joint structure. Detailed examinations were conducted on a lap splice joint panel removed from a full scale fuselage test article after completing a 60,000 cycle pressure test. The panel contained a four bay region that exhibited visible outer skin cracks and regions of crack link-up along the upper rivet row. Destructive examinations revealed undetected fatigue damage in the outer skin, inner skin, and tear strap regions. Outer skin fatigue cracks were found to initiate by fretting damage along the faying surface. The cracks grew along the faying surface to a length equivalent to two to three skin thicknesses before penetrating the outboard surface of the outer skin. Analysis of fracture surface marker bands produced during full scale testing revealed that all upper rivet row fatigue cracks contained in a dim bay region grow at similar rates; this important result suggests that fracture mechanics based methods can be used to predict the growth of outer skin fatigue cracks in lap splice structure. Results are presented showing the affects of MSD and out-of-plane pressure loads on outer skin crack link-up.

Minimizing the RMS surface distortions from gravity loadings of the 34-m HA-DEC antenna for deep space missions

NASA Technical Reports Server (NTRS)

Katow, S. M.

1979-01-01

The computer analysis of the 34-m HA-DEC antenna by the IDEAS program provided the rms distortions of the surface panels support points for full gravity loadings in the three directions of the basic coordinate system of the computer model. The rms distortions for the gravity vector not in line with any of the three basic directions were solved and contour plotted starting from three surface panels setting declination angle. By inspections of the plots, it was concluded that the setting or rigging angle of -15 degrees declination minimized the rms distortions for sky coverage of plus or minus 22 declination angles to 10 degrees of ground mask.

Semi-transparent solar energy thermal storage device

DOEpatents

McClelland, John F.

1986-04-08

A visually transmitting solar energy absorbing thermal storage module includes a thermal storage liquid containment chamber defined by an interior solar absorber panel, an exterior transparent panel having a heat mirror surface substantially covering the exterior surface thereof and associated top, bottom and side walls. Evaporation of the thermal storage liquid is controlled by a low vapor pressure liquid layer that floats on and seals the top surface of the liquid. Porous filter plugs are placed in filler holes of the module. An algicide and a chelating compound are added to the liquid to control biological and chemical activity while retaining visual clarity. A plurality of modules may be supported in stacked relation by a support frame to form a thermal storage wall structure.

Semi-transparent solar energy thermal storage device

DOEpatents

McClelland, John F.

1985-06-18

A visually transmitting solar energy absorbing thermal storage module includes a thermal storage liquid containment chamber defined by an interior solar absorber panel, an exterior transparent panel having a heat mirror surface substantially covering the exterior surface thereof and associated top, bottom and side walls, Evaporation of the thermal storage liquid is controlled by a low vapor pressure liquid layer that floats on and seals the top surface of the liquid. Porous filter plugs are placed in filler holes of the module. An algicide and a chelating compound are added to the liquid to control biological and chemical activity while retaining visual clarity. A plurality of modules may be supported in stacked relation by a support frame to form a thermal storage wall structure.

Recent Advancements in the Numerical Simulation of Surface Irradiance for Solar Energy Applications: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Yu; Sengupta, Manajit; Deline, Chris

This paper briefly reviews the National Renewable Energy Laboratory's recent efforts on developing all-sky solar irradiance models for solar energy applications. The Fast All-sky Radiation Model for Solar applications (FARMS) utilizes the simulation of clear-sky transmittance and reflectance and a parameterization of cloud transmittance and reflectance to rapidly compute broadband irradiances on horizontal surfaces. FARMS delivers accuracy that is comparable to the two-stream approximation, but it is approximately 1,000 times faster. A FARMS-Narrowband Irradiance over Tilted surfaces (FARMS-NIT) has been developed to compute spectral irradiances on photovoltaic (PV) panels in 2002 wavelength bands. Further, FARMS-NIT has been extended for bifacialmore » PV panels.« less

The development and evaluation of advanced Kevlar sandwich structure for application to rotorcraft airframes

NASA Astrophysics Data System (ADS)

Minguet, Pierre; Llorente, Steven; Fay, Russell

1991-05-01

The results of an evaluation of DuPont Kevlar-based material systems in sandwich structure designed for rotorcraft primary airframe structure are presented in this report. The focus of this work has been to evaluate the durability and compression strength of thin-gage Kevlar sandwich panels and investigate means of improvement. It was found that sandwich panels made with Kevlar 149 fibers can be as strong as Kevlar 49 structures but have reduced compression stiffness properties at typical operating strain levels. Thermal cycling was found to affect permeability but not strength in thin facesheet sandwich structure. Any increased permeability can be prevented with the use of an interleaf or surfacing plies. The surfacing plies investigated also had a beneficial effect on sandwich strength due to their stabilizing effect on the facesheet in compression. Finally, a previously developed model was used to analyze the residual strength of a sandwich panel after impact damage.

Design and fabrication of a super alloy thermal protection system

NASA Technical Reports Server (NTRS)

Varisco, A.; Wolter, W.; Bell, P.

1978-01-01

A lightweight metallic TPS was designed, and two test articles were fabricated, one from Haynes 188 and one from Rene 41. A baseline TPS concept, selected at the beginning of the program, consisted of a Haynes 25 corrugation-stiffened beaded skin surface panel, a specially designed support system, and an insulation system. By optimizing the structure for the design loads and by chem-milling to remove material not needed, the mass of the baseline surface panel was reduced 25%, and the mass of the support structure was reduced 50%. The insulation system mass was reduced 40% by using two types of insulation, each suited to its temperature range, and by eliminating a foul bag which encapsulated the baseline insulation system. These reductions resulted in an overall 35% reduction in mass of the Haynes 188 panel from the baseline Haynes 25 design. Similar reductions were achieved with the Rene 41 system.

Architectural Panels

NASA Technical Reports Server (NTRS)

1985-01-01

Alliance Wall Corporation's Whyteboard, a porcelain enamel on steel panels wall board, owes its color stability to a KIAC engineering background study to identify potential technologies and manufacturers of equipment which could be used to detect surface flaws. One result of the data base search was the purchase of a spectrocolorimeter which enables the company to control some 250 standard colors, and match special colors.

Portable apparatus for surface evaluation of furniture panels

Treesearch

B. G. Heebink

1963-01-01

In 1959, a new technique was devised at the Forest Products Laboratory that provided a means of examining, evaluating, and recording the show- through pattern (often called telegraphing) of panels made with particle board cores. Although the technique was devised as a working tool to evaluate show-through characteristics of particle board cores, it can be used equally...

Effect of surface fouling on the output of PV panels

NASA Astrophysics Data System (ADS)

Zhang, Zele

2018-04-01

Surface fouling on the photovoltaic system caused by the output of a certain impact, therefore, it is very important to explore the effect of fouling on its contribution. Through the use of photovoltaic panels to collect Baoding area under different weather output data, and the collected data for comparative analysis, obtained under different environments on the impact of its contribution. It is concluded that the output of the photovoltaic cells will decrease, and the power drop rate will stabilize after three or four days. The effect of fouling on the fog haze and low temperature is more obvious.

High temperature, high intensity solar array. [for Venus Radar Mapper mission

NASA Technical Reports Server (NTRS)

Smith, B. S.; Brooks, G. R.; Pinkerton, R.

1985-01-01

The solar array for the Venus Radar Mapper mission will operate in the high temperature, high intensity conditions of a low Venus orbit environment. To fulfill the performance requirements in this environment at minimum cost and mass while maximizing power density and packing factor on the panel surface, several features were introduced into the design. These features included the use of optical surface reflectors (OSR's) to reduce the operating temperature; new adhesives for conductive bonding of OSR's to avoid electrostatic discharges; custom-designed large area cells and novel shunt diode circuit and panel power harness configurations.

Energy and Process Optimization Assessment at U.S. Army Installation in Germany: Keiserslautern Army Depot, Piermasens Army Depot, Katterbach Kaserne, Storck Barracks in Illesheim, and U.S. Army Garrison Wiesbaden Schools

DTIC Science & Technology

2007-09-01

Solution Paint the ceiling white with paint suitable for mineral wool surfaces. Also a white surface material is possible—this would keep fibers...from the mineral wool from being carried into the indoor air by air movement. 4.2.19.3 Savings No saving can be indicated; the lights in the...concrete panels be- tween reinforced concrete columns. The concrete panels are covered from the outside with about 4 cm of mineral wool , 2 cm ventilated

Development of Surfaces Optically Suitable for Flat Solar Panels

NASA Technical Reports Server (NTRS)

Desmet, D.; Jason, A.

1978-01-01

Three areas of research in the development of flat solar panels are described. (1) A reflectometer which can separately evaluate the spectral and diffuse reflectivities of surfaces was developed. The reflectometer has a phase locked detection system. (2) A coating composed of strongly bound copper oxide that is formed by an etching process performed on an aluminum alloy with high copper content was also developed. Because of this one step fabrication process, fabrication costs are expected to be small. (3) A literature search was conducted and conclusions on the required optical properties of flat plate solar collectors are presented.

Sound transmission through triple-panel structures lined with poroelastic materials

NASA Astrophysics Data System (ADS)

Liu, Yu

2015-03-01

In this paper, previous theories on the prediction of sound transmission loss for a double-panel structure lined with poroelastic materials are extended to address the problem of a triple-panel structure. Six typical configurations are considered for a triple-panel structure based on the method of coupling the porous layers to the facing panels which determines critically the sound insulation performance of the system. The transfer matrix method is employed to solve the system by applying appropriate types of boundary conditions for these configurations. The transmission loss of the triple-panel structures in a diffuse sound field is calculated as a function of frequency and compared with that of corresponding double-panel structures. Generally, the triple-panel structure with poroelastic linings has superior acoustic performance to the double-panel counterpart, remarkably in the mid-high frequency range and possibly at low frequencies, by selecting appropriate configurations in which those with two air gaps in the structure exhibit the best overall performance over the entire frequency range. The poroelastic lining significantly lowers the cut-on frequency above which the triple-panel structure exhibits noticeably higher transmission loss. Compared with a double-panel structure, the wider range of system parameters for a triple-panel structure due to the additional partition provides more design space for tuning the sound insulation performance. Despite the increased structural complexity, the triple-panel structure lined with poroelastic materials has the obvious advantages in sound transmission loss while without the penalties in weight and volume, and is hence a promising replacement for the widely used double-panel sandwich structure.

Enhancements of Tow-Steering Design Techniques: Design of Rectangular Panel Under Combined Loads

NASA Technical Reports Server (NTRS)

Tatting, Brian F.; Setoodeh, Shahriar; Gurdal, Zafer

2005-01-01

An extension to existing design tools that utilize tow-steering is presented which is used to investigate the use of elastic tailoring for a flat panel with a central hole under combined loads of compression and shear. The elastic tailoring is characterized by tow-steering within individual lamina as well as a novel approach based on selective reinforcement, which attempts to minimize compliance through the use of Cellular Automata design concepts. The selective reinforcement designs lack any consideration of manufacturing constraints, so a new tow-steered path definition was developed to translate the prototype selective reinforcement designs into manufacturable plies. The minimum weight design of a flat panel under combined loading was based on a model provided by NASA-Langley personnel and analyzed by STAGS within the OLGA design environment. Baseline designs using traditional straight fiber plies were generated, as well as tow-steered designs which incorporated parallel, tow-drop, and overlap plies within the laminate. These results indicated that the overlap method provided the best improvement with regards to weight and performance as compared to traditional constant stiffness monocoque panels, though the laminates did not measure up to similar designs from the literature using sandwich and isogrid constructions. Further design studies were conducted using various numbers of the selective reinforcement plies at the core and outer surface of the laminate. None of these configurations exhibited notable advantages with regard to weight or buckling performance. This was due to the fact that the minimization of the compliance tended to direct the major stresses toward the center of the panel, which decreased the ability of the structure to withstand loads leading to instability.

Large Coded Aperture Mask for Spaceflight Hard X-ray Images

NASA Technical Reports Server (NTRS)

Vigneau, Danielle N.; Robinson, David W.

2002-01-01

The 2.6 square meter coded aperture mask is a vital part of the Burst Alert Telescope on the Swift mission. A random, but known pattern of more than 50,000 lead tiles, each 5 mm square, was bonded to a large honeycomb panel which projects a shadow on the detector array during a gamma ray burst. A two-year development process was necessary to explore ideas, apply techniques, and finalize procedures to meet the strict requirements for the coded aperture mask. Challenges included finding a honeycomb substrate with minimal gamma ray attenuation, selecting an adhesive with adequate bond strength to hold the tiles in place but soft enough to allow the tiles to expand and contract without distorting the panel under large temperature gradients, and eliminating excess adhesive from all untiled areas. The largest challenge was to find an efficient way to bond the > 50,000 lead tiles to the panel with positional tolerances measured in microns. In order to generate the desired bondline, adhesive was applied and allowed to cure to each tile. The pre-cured tiles were located in a tool to maintain positional accuracy, wet adhesive was applied to the panel, and it was lowered to the tile surface with synchronized actuators. Using this procedure, the entire tile pattern was transferred to the large honeycomb panel in a single bond. The pressure for the bond was achieved by enclosing the entire system in a vacuum bag. Thermal vacuum and acoustic tests validated this approach. This paper discusses the methods, materials, and techniques used to fabricate this very large and unique coded aperture mask for the Swift mission.

Heat Rejection Concepts for Lunar Fission Surface Power Applications

NASA Technical Reports Server (NTRS)

Siamidis, John

2006-01-01

This paper describes potential heat rejection design concepts for lunar surface Brayton power conversion systems. Brayton conversion systems are currently under study by NASA for surface power applications. Surface reactors may be used for the moon to power human outposts enabling extended stays and closed loop life support. The Brayton Heat Rejection System (HRS) must dissipate waste heat generated by the power conversion system due to inefficiencies in the thermal-to-electric conversion process. Space Brayton conversion system designs tend to optimize at efficiencies of about 20 to 25 percent with radiator temperatures in the 400 K to 600 K range. A notional HRS was developed for a 100 kWe-class Brayton power system that uses a pumped water heat transport loop coupled to a water heat pipe radiator. The radiator panels employ a tube and fin construction consisting of regularly-spaced circular heat pipes contained within two composite facesheets. The water heat pipes interface to the coolant through curved sections partially contained within the cooling loop. The paper evaluates various design parameters including radiator panel orientation, coolant flow path, and facesheet thickness. Parameters were varied to compare design options on the basis of H2O pump pressure rise and required power, heat pipe unit power and radial flux, radiator area, radiator panel areal mass, and overall HRS mass.

Micromilled optical elements for edge-lit illumination panels

NASA Astrophysics Data System (ADS)

Ronny, Rahima Afrose; Knopf, George K.; Bordatchev, Evgueni; Nikumb, Suwas

2013-04-01

Edge-lit light guide panels (LGPs) with micropatterned surfaces represent a new technology for developing small- and medium-sized illumination sources for application such as automotive, residential lighting, and advertising displays. The shape, density, and spatial distribution of the micro-optical structures (MOSs) imprinted on the transparent LGP must be selected to achieve high brightness and uniform luminance over the active surface. We examine how round-tip cylindrical MOSs fabricated by precision micromilling can be used to create patterned surfaces on low-cost transparent polymethyl-methacrylate substrates for high-intensity illumination applications. The impact of varying the number, pitch, spatial distribution, and depth of the optical microstructures on lighting performance is initially investigated using LightTools™ simulation software. To illustrate the microfabrication process, several 100×100×6 mm3 LGP prototypes are constructed and tested. The prototypes include an "optimized" array of MOSs that exhibit near-uniform illumination (approximately 89%) across its active light-emitting surface. Although the average illumination was 7.3% less than the value predicted from numerical simulation, it demonstrates how LGPs can be created using micromilling operations. Customized MOS arrays with a bright rectangular pattern near the center of the panel and a sequence of MOSs that illuminate a predefined logo are also presented.

Affect of Air Leakage into a Thermal-Vacuum Chamber on Helium Refrigeration Heat Load

NASA Technical Reports Server (NTRS)

Garcia, Sam; Meagher, Daniel; Linza, Robert; Saheli, Fariborz; Vargas, Gerardo; Lauterbach, John; Reis, Carl; Ganni, Venkatarao (Rao); Homan, Jonathan

2008-01-01

NASA s Johnson Space Center (JSC) Building 32 houses two large thermal-vacuum chambers (Chamber A and Chamber B). Within these chambers are liquid nitrogen shrouds to provide a thermal environment and helium panels which operate at 20K to provide cryopumping. Some amount of air leakage into the chambers during tests is inevitable. This causes "air fouling" of the helium panel surfaces due to the components of the air that adhere to the panels. The air fouling causes the emittance of the helium panels to increase during tests. The increase in helium panel emittance increases the heat load on the helium refrigerator that supplies the 20K helium for those panels. Planning for thermal-vacuum tests should account for this increase to make sure that the helium refrigerator capacity will not be exceeded over the duration of a test. During a recent test conducted in Chamber B a known-size air leak was introduced to the chamber. Emittance change of the helium panels and the affect on the helium refrigerator was characterized. A description of the test and the results will be presented.

Color Image of Phoenix Lander on Mars Surface

NASA Image and Video Library

2008-05-27

This is an enhanced-color image from Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment HiRISE camera. It shows the NASA Mars Phoenix lander with its solar panels deployed on the Mars surface

21 CFR 660.4 - Potency test.

Code of Federal Regulations, 2012 CFR

2012-04-01

... STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Antibody to Hepatitis B Surface Antigen § 660.4 Potency test. To be satisfactory for release, each filling of Antibody to Hepatitis B Surface Antigen shall be tested against the Reference Hepatitis B Surface Antigen Panel and shall be sufficiently potent...

21 CFR 660.4 - Potency test.

Code of Federal Regulations, 2011 CFR

2011-04-01

... STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Antibody to Hepatitis B Surface Antigen § 660.4 Potency test. To be satisfactory for release, each filling of Antibody to Hepatitis B Surface Antigen shall be tested against the Reference Hepatitis B Surface Antigen Panel and shall be sufficiently potent...

21 CFR 660.4 - Potency test.

Code of Federal Regulations, 2014 CFR

2014-04-01

... STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Antibody to Hepatitis B Surface Antigen § 660.4 Potency test. To be satisfactory for release, each filling of Antibody to Hepatitis B Surface Antigen shall be tested against the Reference Hepatitis B Surface Antigen Panel and shall be sufficiently potent...

21 CFR 660.4 - Potency test.

Code of Federal Regulations, 2010 CFR

2010-04-01

... STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Antibody to Hepatitis B Surface Antigen § 660.4 Potency test. To be satisfactory for release, each filling of Antibody to Hepatitis B Surface Antigen shall be tested against the Reference Hepatitis B Surface Antigen Panel and shall be sufficiently potent...

Vortex lattice prediction of subsonic aerodynamics of hypersonic vehicle concepts

NASA Technical Reports Server (NTRS)

Pittman, J. L.; Dillon, J. L.

1977-01-01

The vortex lattice method introduced by Lamar and Gloss (1975) was applied to the prediction of subsonic aerodynamic characteristics of hypersonic body-wing configurations. The reliability of the method was assessed through comparison of the calculated and observed aerodynamic performances of two National Hypersonic Flight Research Facility craft at Mach 0.2. The investigation indicated that a vortex lattice model involving 120 or more panel elements can give good results for the lift and induced drag coefficients of the craft, as well as for the pitching moment at angles of attack below 10 to 15 deg. Automated processes for calculating the local slopes of mean-camber surfaces may also render the method suitable for use in preliminary design phases.

Thermal and Mechanical Buckling Analysis of Hypersonic Aircraft Hat-Stiffened Panels With Varying Face Sheet Geometry and Fiber Orientation

NASA Technical Reports Server (NTRS)

Ko, William L.

1996-01-01

Mechanical and thermal buckling behavior of monolithic and metal-matrix composite hat-stiffened panels were investigated. The panels have three types of face-sheet geometry: Flat face sheet, microdented face sheet, and microbulged face sheet. The metal-matrix composite panels have three types of face-sheet layups, each of which is combined with various types of hat composite layups. Finite-element method was used in the eigenvalue extractions for both mechanical and thermal buckling. The thermal buckling analysis required both eigenvalue and material property iterations. Graphical methods of the dual iterations are shown. The mechanical and thermal buckling strengths of the hat-stiffened panels with different face-sheet geometry are compared. It was found that by just microdenting or microbulging of the face sheet, the axial, shear, and thermal buckling strengths of both types of hat-stiffened panels could be enhanced considerably. This effect is more conspicuous for the monolithic panels. For the metal-matrix composite panels, the effect of fiber orientations on the panel buckling strengths was investigated in great detail, and various composite layup combinations offering, high panel buckling strengths are presented. The axial buckling strength of the metal-matrix panel was sensitive to the change of hat fiber orientation. However, the lateral, shear, and thermal buckling strengths were insensitive to the change of hat fiber orientation.

Behavior of Frame-Stiffened Composite Panels with Damage

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.

2013-01-01

NASA, the Air Force Research Laboratory and The Boeing Company have worked to develop new low-cost, light-weight composite structures for aircraft. A Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept has been developed which offers advantages over traditional metallic structures. In this concept, a stitched carbon-epoxy material system has been developed with the potential for reducing the weight and cost of transport aircraft structure by eliminating fasteners, thereby reducing part count and labor. Stitching and the use of thin skins with rod-stiffeners to move loading away from the morevulnerable outer surface produces a structurally efficient, damage tolerant design. This study focuses on the behavior of PRSEUS panels loaded in the frame direction and subjected to severe damage in the form of a severed central frame in a three-frame panel. Experimental results for a pristine two-frame panel and analytical predictions for pristine two-frame and three-frame panels as well as damaged three-frame panels are described.

Optimization of composite sandwich cover panels subjected to compressive loadings

NASA Technical Reports Server (NTRS)

Cruz, Juan R.

1991-01-01

An analysis and design method is presented for the design of composite sandwich cover panels that includes transverse shear effects and damage tolerance considerations. This method is incorporated into an optimization program called SANDOP (SANDwich OPtimization). SANDOP is used in the present study to design optimized composite sandwich cover panels for transport aircraft wing applications as a demonstration of its capabilities. The results of this design study indicate that optimized composite sandwich cover panels have approximately the same structural efficiency as stiffened composite cover panels designed to identical constraints. Results indicate that inplane stiffness requirements have a large effect on the weight of these composite sandwich cover panels at higher load levels. Increasing the maximum allowable strain and the upper percentage limit of the 0 degree and plus or minus 45 degree plies can yield significant weight savings. The results show that the structural efficiency of these optimized composite sandwich cover panels is relatively insensitive to changes in core density.

Ascertainment bias from imputation methods evaluation in wheat.

PubMed

Brandariz, Sofía P; González Reymúndez, Agustín; Lado, Bettina; Malosetti, Marcos; Garcia, Antonio Augusto Franco; Quincke, Martín; von Zitzewitz, Jarislav; Castro, Marina; Matus, Iván; Del Pozo, Alejandro; Castro, Ariel J; Gutiérrez, Lucía

2016-10-04

Whole-genome genotyping techniques like Genotyping-by-sequencing (GBS) are being used for genetic studies such as Genome-Wide Association (GWAS) and Genomewide Selection (GS), where different strategies for imputation have been developed. Nevertheless, imputation error may lead to poor performance (i.e. smaller power or higher false positive rate) when complete data is not required as it is for GWAS, and each marker is taken at a time. The aim of this study was to compare the performance of GWAS analysis for Quantitative Trait Loci (QTL) of major and minor effect using different imputation methods when no reference panel is available in a wheat GBS panel. In this study, we compared the power and false positive rate of dissecting quantitative traits for imputed and not-imputed marker score matrices in: (1) a complete molecular marker barley panel array, and (2) a GBS wheat panel with missing data. We found that there is an ascertainment bias in imputation method comparisons. Simulating over a complete matrix and creating missing data at random proved that imputation methods have a poorer performance. Furthermore, we found that when QTL were simulated with imputed data, the imputation methods performed better than the not-imputed ones. On the other hand, when QTL were simulated with not-imputed data, the not-imputed method and one of the imputation methods performed better for dissecting quantitative traits. Moreover, larger differences between imputation methods were detected for QTL of major effect than QTL of minor effect. We also compared the different marker score matrices for GWAS analysis in a real wheat phenotype dataset, and we found minimal differences indicating that imputation did not improve the GWAS performance when a reference panel was not available. Poorer performance was found in GWAS analysis when an imputed marker score matrix was used, no reference panel is available, in a wheat GBS panel.

Correcting Thermal Deformations in an Active Composite Reflector

NASA Technical Reports Server (NTRS)

Bradford, Samuel C.; Agnes, Gregory S.; Wilkie, William K.

2011-01-01

Large, high-precision composite reflectors for future space missions are costly to manufacture, and heavy. An active composite reflector capable of adjusting shape in situ to maintain required tolerances can be lighter and cheaper to manufacture. An active composite reflector testbed was developed that uses an array of piezoelectric composite actuators embedded in the back face sheet of a 0.8-m reflector panel. Each individually addressable actuator can be commanded from 500 to +1,500 V, and the flatness of the panel can be controlled to tolerances of 100 nm. Measuring the surface flatness at this resolution required the use of a speckle holography interferometer system in the Precision Environmental Test Enclosure (PETE) at JPL. The existing testbed combines the PETE for test environment stability, the speckle holography system for measuring out-of-plane deformations, the active panel including an array of individually addressable actuators, a FLIR thermal camera to measure thermal profiles across the reflector, and a heat source. Use of an array of flat piezoelectric actuators to correct thermal deformations is a promising new application for these actuators, as is the use of this actuator technology for surface flatness and wavefront control. An isogrid of these actuators is moving one step closer to a fully active face sheet, with the significant advantage of ease in manufacturing. No extensive rib structure or other actuation backing structure is required, as these actuators can be applied directly to an easy-to-manufacture flat surface. Any mission with a surface flatness requirement for a panel or reflector structure could adopt this actuator array concept to create lighter structures and enable improved performance on orbit. The thermal environment on orbit tends to include variations in temperature during shadowing or changes in angle. Because of this, a purely passive system is not an effective way to maintain flatness at the scale of microns over several meters. This technology is specifically referring to correcting thermal deformations of a large, flat structure to a specified tolerance. However, the underlying concept (an array of actuators on the back face of a panel for correcting the flatness of the front face) could be extended to many applications, including energy harvesting, changing the wavefront of an optical system, and correcting the flatness of an array of segmented deployable panels.

Spectroscopic characterization of sixteenth century panel painting references using Raman, surface-enhanced Raman spectroscopy and helium-Raman system for in situ analysis of Ibero-American Colonial paintings

NASA Astrophysics Data System (ADS)

García-Bucio, María Angélica; Casanova-González, Edgar; Ruvalcaba-Sil, José Luis; Arroyo-Lemus, Elsa; Mitrani-Viggiano, Alejandro

2016-12-01

Colonial panel paintings constitute an essential part of Latin-American cultural heritage. Their study is vital for understanding the manufacturing process, including its evolution in history, as well as its authorship, dating and other information significant to art history and conservation purposes. Raman spectroscopy supplies a non-destructive characterization tool, which can be implemented for in situ analysis, via portable equipment. Specific methodologies must be developed, comprising the elaboration of reference panel paintings using techniques and materials similar to those of the analysed period, as well as the determination of the best analysis conditions for different pigments and ground preparations. In order to do so, Raman spectroscopy at 532, 785 and 1064 nm, surface-enhanced Raman spectroscopy (SERS) and a helium-Raman system were applied to a panel painting reference, in combination with X-ray fluorescence analysis. We were able to establish the analysis conditions for a number of sixteenth century pigments and dyes, and other relevant components of panel paintings from this period, 1064 nm Raman and SERS being the most successful. The acquired spectra contain valuable specific information for their identification and they conform a very useful database that can be applied to the analysis of Ibero-American Colonial paintings. This article is part of the themed issue "Raman spectroscopy in art and archaeology".

Solar Concentrator Advanced Development Program

NASA Technical Reports Server (NTRS)

Knasel, Don; Ehresman, Derik

1989-01-01

The Solar Concentrator Advanced Development Project has successfully designed, fabricated, and tested a full scale prototypical solar dynamic concentrator for space station applications. A Truss Hexagonal Panel reflector was selected as a viable solar concentrator concept to be used for space station applications. This concentrator utilizes a modular design approach and is flexible in attainable flux profiles and assembly techniques. The detailed design of the concentrator, which included structural, thermal and optical analysis, identified the feasibility of the design and specific technologies that were required to fabricate it. The needed surface accuracy of the reflectors surface was found to be very tight, within 5 mrad RMS slope error, and results in very close tolerances for fabrication. To meet the design requirements, a modular structure composed of hexagonal panels was used. The panels, made up of graphite epoxy box beams provided the strength, stiffness and dimensional stability needed. All initial project requirements were met or exceeded by hardware demonstration. Initial testing of structural repeatability of a seven panel portion of the concentrator was followed by assembly and testing of the full nineteen panel structure. The testing, which consisted of theodolite and optical measurements over an assembly-disassembly-reassembly cycle, demonstrated that the concentrator maintained the as-built contour and optical characteristics. The facet development effort within the project, which included developing the vapor deposited reflective facet, produced a viable design with demonstrated optical characteristics that are within the project goals.

Buckling analysis and test correlation of hat stiffened panels for hypersonic vehicles

NASA Technical Reports Server (NTRS)

Percy, Wendy C.; Fields, Roger A.

1990-01-01

The paper discusses the design, analysis, and test of hat stiffened panels subjected to a variety of thermal and mechanical load conditions. The panels were designed using data from structural optimization computer codes and finite element analysis. Test methods included the grid shadow moire method and a single gage force stiffness method. The agreement between the test data and analysis provides confidence in the methods that are currently being used to design structures for hypersonic vehicles. The agreement also indicates that post buckled strength may potentially be used to reduce the vehicle weight.

Recommendations for numerical solution of reinforced-panel and fuselage-ring problems

NASA Technical Reports Server (NTRS)

Hoff, N J; Libby, Paul A

1949-01-01

Procedures are recommended for solving the equations of equilibrium of reinforced panels and isolated fuselage rings as represented by the external loads and the operations table established according to Southwell's method. From the solution of these equations the stress distribution can be easily determined. The method of systematic relaxations, the matrix-calculus method, and several other methods applicable in special cases are discussed. Definite recommendations are made for obtaining the solution of reinforced-panel problems which are generally designated as shear lag problems. The procedures recommended are demonstrated in the analysis of a number of panels. In the case of fuselage rings it is not possible to make definite recommendations for the solution of the equilibrium equations for all rings and loadings. However, suggestions based on the latest experience are made and demonstrated on several rings.

A Flexible and Accurate Genotype Imputation Method for the Next Generation of Genome-Wide Association Studies

PubMed Central

Howie, Bryan N.; Donnelly, Peter; Marchini, Jonathan

2009-01-01

Genotype imputation methods are now being widely used in the analysis of genome-wide association studies. Most imputation analyses to date have used the HapMap as a reference dataset, but new reference panels (such as controls genotyped on multiple SNP chips and densely typed samples from the 1,000 Genomes Project) will soon allow a broader range of SNPs to be imputed with higher accuracy, thereby increasing power. We describe a genotype imputation method (IMPUTE version 2) that is designed to address the challenges presented by these new datasets. The main innovation of our approach is a flexible modelling framework that increases accuracy and combines information across multiple reference panels while remaining computationally feasible. We find that IMPUTE v2 attains higher accuracy than other methods when the HapMap provides the sole reference panel, but that the size of the panel constrains the improvements that can be made. We also find that imputation accuracy can be greatly enhanced by expanding the reference panel to contain thousands of chromosomes and that IMPUTE v2 outperforms other methods in this setting at both rare and common SNPs, with overall error rates that are 15%–20% lower than those of the closest competing method. One particularly challenging aspect of next-generation association studies is to integrate information across multiple reference panels genotyped on different sets of SNPs; we show that our approach to this problem has practical advantages over other suggested solutions. PMID:19543373

Open Circuit Resonant (SansEC) Sensor Technology for Lightning Mitigation and Damage Detection and Diagnosis for Composite Aircraft Applications

NASA Technical Reports Server (NTRS)

Szatkowski, George N.; Dudley, Kenneth L.; Smith, Laura J.; Wang, Chuantong; Ticatch, Larry A.

2014-01-01

Traditional methods to protect composite aircraft from lightning strike damage rely on a conductive layer embedded on or within the surface of the aircraft composite skin. This method is effective at preventing major direct effect damage and minimizes indirect effects to aircraft systems from lightning strike attachment, but provides no additional benefit for the added parasitic weight from the conductive layer. When a known lightning strike occurs, the points of attachment and detachment on the aircraft surface are visually inspected and checked for damage by maintenance personnel to ensure continued safe flight operations. A new multi-functional lightning strike protection (LSP) method has been developed to provide aircraft lightning strike protection, damage detection and diagnosis for composite aircraft surfaces. The method incorporates a SansEC sensor array on the aircraft exterior surfaces forming a "Smart skin" surface for aircraft lightning zones certified to withstand strikes up to 100 kiloamperes peak current. SansEC sensors are open-circuit devices comprised of conductive trace spiral patterns sans (without) electrical connections. The SansEC sensor is an electromagnetic resonator having specific resonant parameters (frequency, amplitude, bandwidth & phase) which when electromagnetically coupled with a composite substrate will indicate the electrical impedance of the composite through a change in its resonant response. Any measureable shift in the resonant characteristics can be an indication of damage to the composite caused by a lightning strike or from other means. The SansEC sensor method is intended to diagnose damage for both in-situ health monitoring or ground inspections. In this paper, the theoretical mathematical framework is established for the use of open circuit sensors to perform damage detection and diagnosis on carbon fiber composites. Both computational and experimental analyses were conducted to validate this new method and system for aircraft composite damage detection and diagnosis. Experimental test results on seeded fault damage coupons and computational modeling simulation results are presented. This paper also presents the shielding effectiveness along with the lightning direct effect test results from several different SansEC LSP and baseline protected and unprotected carbon fiber reinforced polymer (CFRP) test panels struck at 40 and 100 kiloamperes following a universal common practice test procedure to enable damage comparisons between SansEC LSP configurations and common practice copper mesh LSP approaches. The SansEC test panels were mounted in a LSP test bed during the lightning test. Electrical, mechanical and thermal parameters were measured during lightning attachment and are presented with post test nondestructive inspection comparisons. The paper provides correlational results between the SansEC sensors computed electric field distribution and the location of the lightning attachment on the sensor trace and visual observations showing the SansEC sensor's affinity for dispersing the lightning attachment.

Environmental Panels as a Proxy for Nursing Facility Patients With Methicillin-Resistant Staphylococcus Aure and Vancomycin-Resistant Enterococcus Colonization.

PubMed

Cassone, Marco; Mantey, Julia; Perri, Mary Beth; Gibson, Kristen; Lansing, Bonnie; McNamara, Sara; Patel, Payal K; Cheng, Vincent C C; Walters, Maroya S; Stone, Nimalie D; Zervos, Marcus J; Mody, Lona

2018-05-02

Most nursing facilities (NFs) lack methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) surveillance programs due to limited resources and high costs. We investigated the utility of environmental screening of high-touch surfaces in patient rooms as a way to circumvent these challenges. We compared MRSA and VRE culture data from high-touch surfaces in patients' rooms (14450 samples from 6 NFs) and ranked each site's performance in predicting patient colonization (7413 samples). The best-performing sites were included in a MRSA- and a VRE-specific panel that functioned as a proxy for patient colonization. Molecular typing was performed to confirm available concordant patient-environment pairs. We identified and validated a MRSA panel that consisted of the bed controls, nurse call button, bed rail, and TV remote control. The VRE panel included the toilet seat, bed controls, bed rail, TV remote control, and top of the side table. Panel colonization data tracked patient colonization. Negative predictive values were 89%-92% for MRSA and 82%-84% for VRE. Molecular typing confirmed a strong clonal type relationship in available concordant patient-environment pairs (98% for MRSA, 91% for VRE), pointing to common epidemiological patterns for environmental and patient isolates. Environmental panels used as a proxy for patient colonization and incorporated into facility surveillance protocols can guide decolonization strategies, improve awareness of MRSA and VRE burden, and inform efforts to reduce transmission. Targeted environmental screening may be a viable surveillance strategy for MRSA and VRE detection in NFs.

Testing of DLR C/C-SiC and C/C for HIFiRE 8 Scramjet Combustor

NASA Technical Reports Server (NTRS)

Glass, David E.; Capriotti, Diego P.; Reimer, Thomas; Kutemeyer, Marius; Smart, Michael K.

2014-01-01

Ceramic Matrix Composites (CMCs) have been proposed for use as lightweight hot structures in scramjet combustors. Previous studies have calculated significant weight savings by utilizing CMCs (active and passive) versus actively cooled metallic scramjet structures. Both a carbon/carbon (C/C) and a carbon/carbon-silicon carbide (C/C-SiC) material fabricated by DLR (Stuttgart, Germany) are being considered for use in a passively cooled combustor design for Hypersonic International Flight Research Experimentation (HIFiRE) 8, a joint Australia / Air Force Research Laboratory hypersonic flight program, expected to fly at Mach 7 for approximately 30 sec, at a dynamic pressure of 55 kilopascals. Flat panels of the DLR C/C and C/C-SiC materials were installed downstream of a hydrogen-fueled, dual-mode scramjet combustor and tested for several minutes at conditions simulating flight at Mach 5 and Mach 6. Gaseous hydrogen fuel was used to fuel the scramjet combustor. The test panels were instrumented with embedded Type K and Type S thermocouples. Zirconia felt insulation was used during some of the tests to reduce heat loss from the back surface and thus increase the heated surface temperature of the C/C-SiC panel approximately 177 C (350 F). The final C/C-SiC panel was tested for three cycles totaling over 135 sec at Mach 6 enthalpy. Slightly more erosion was observed on the C/C panel than the C/C-SiC panels, but both material systems demonstrated acceptable recession performance for the HIFiRE 8 flight.

Direction and Integration of Experimental Ground Test Capabilities and Computational Methods

NASA Technical Reports Server (NTRS)

Dunn, Steven C.

2016-01-01

This paper groups and summarizes the salient points and findings from two AIAA conference panels targeted at defining the direction, with associated key issues and recommendations, for the integration of experimental ground testing and computational methods. Each panel session utilized rapporteurs to capture comments from both the panel members and the audience. Additionally, a virtual panel of several experts were consulted between the two sessions and their comments were also captured. The information is organized into three time-based groupings, as well as by subject area. These panel sessions were designed to provide guidance to both researchers/developers and experimental/computational service providers in defining the future of ground testing, which will be inextricably integrated with the advancement of computational tools.

Analysis of stresses in finite anisotropic panels with centrally located cutouts

NASA Technical Reports Server (NTRS)

Britt, Vicki O.

1992-01-01

A method for analyzing biaxial- and shear-loaded anisotropic rectangular panels with centrally located circular and elliptical cutouts is presented in the present paper. The method is based on Lekhnitskii's complex variable equations of plane elastostatics combined with a boundary collocation method and a Laurent series approximation. Results are presented for anisotropic panels with elliptical cutouts and subjected to combined shear and compression loading. The effects on the stress field of panel aspect ratio, anisotropy, cutout size, and cutout orientation are addressed. Angle-ply laminates, unidirectional off-axis laminates, and ((+ or - 45/0/90)(sub 3))s, ((+ or - 45/0(sub 2))(sub 3))s, and ((+ or - 45/90(sub 2))(sub 3))s laminates are examined.

Analysis of hourly crash likelihood using unbalanced panel data mixed logit model and real-time driving environmental big data.

PubMed

Chen, Feng; Chen, Suren; Ma, Xiaoxiang

2018-06-01

Driving environment, including road surface conditions and traffic states, often changes over time and influences crash probability considerably. It becomes stretched for traditional crash frequency models developed in large temporal scales to capture the time-varying characteristics of these factors, which may cause substantial loss of critical driving environmental information on crash prediction. Crash prediction models with refined temporal data (hourly records) are developed to characterize the time-varying nature of these contributing factors. Unbalanced panel data mixed logit models are developed to analyze hourly crash likelihood of highway segments. The refined temporal driving environmental data, including road surface and traffic condition, obtained from the Road Weather Information System (RWIS), are incorporated into the models. Model estimation results indicate that the traffic speed, traffic volume, curvature and chemically wet road surface indicator are better modeled as random parameters. The estimation results of the mixed logit models based on unbalanced panel data show that there are a number of factors related to crash likelihood on I-25. Specifically, weekend indicator, November indicator, low speed limit and long remaining service life of rutting indicator are found to increase crash likelihood, while 5-am indicator and number of merging ramps per lane per mile are found to decrease crash likelihood. The study underscores and confirms the unique and significant impacts on crash imposed by the real-time weather, road surface, and traffic conditions. With the unbalanced panel data structure, the rich information from real-time driving environmental big data can be well incorporated. Copyright © 2018 National Safety Council and Elsevier Ltd. All rights reserved.

Impact damage in aircraft composite sandwich panels

NASA Astrophysics Data System (ADS)

Mordasky, Matthew D.

An experimental study was conducted to develop an improved understanding of the damage caused by runway debris and environmental threats on aircraft structures. The velocities of impacts for stationary aircraft and aircraft under landing and takeoff speeds was investigated. The impact damage by concrete, asphalt, aluminum, hail and rubber sphere projectiles was explored in detail. Additionally, a kinetic energy and momentum experimental study was performed to look at the nature of the impacts in more detail. A method for recording the contact force history of the impact by an instrumented projectile was developed and tested. The sandwich composite investigated was an IM7-8552 unidirectional prepreg adhered to a NOMEXRTM core with an FM300K film adhesive. Impact experiments were conducted with a gas gun built in-house specifically for delivering projectiles to a sandwich composite target in this specic velocity regime (10--140 m/s). The effect on the impact damage by the projectile was investigated by ultrasonic C-scan, high speed camera and scanning electron and optical microscopy. Ultrasonic C-scans revealed the full extent of damage caused by each projectile, while the high speed camera enabled precise projectile velocity measurements that were used for striking velocity, kinetic energy and momentum analyses. Scanning electron and optical images revealed specific features of the panel failure and manufacturing artifacts within the lamina and honeycomb core. The damage of the panels by different projectiles was found to have a similar damage area for equivalent energy levels, except for rubber which had a damage area that increased greatly with striking velocity. Further investigation was taken by kinetic energy and momentum based comparisons of 19 mm diameter stainless steel sphere projectiles in order to examine the dominating damage mechanisms. The sandwich targets were struck by acrylic, aluminum, alumina, stainless steel and tungsten carbide spheres of the same geometry (19mm diameter) and surface finish. A peak absorbed energy for perforation of 34.5J was identied regardless of the projectile density. The effect of composite panel manufacturing methods on the impact damage and energy absorption of the panel was also investigated. Specifically, damage related to pre-cured facesheets is compared to the co-cured facesheets used throughout the study.

Out-coupling membrane for large-size organic light-emitting panels with high efficiency and improved uniformity

NASA Astrophysics Data System (ADS)

Ding, Lei; Wang, Lu-Wei; Zhou, Lei; Zhang, Fang-hui

2016-12-01

An out-coupling membrane embedded with a scattering film of SiO2 spheres and polyethylene terephthalate (PET) plastic was successfully developed for 150 × 150 mm2 green OLEDs. Comparing with a reference OLED panel, an approximately 1-fold enhancement in the forward emission was obtained with an out-coupling membrane adhered to the surface of the external glass substrate of the panel. Moreover, it was verified that the emission color at different viewing angles can be stabilized without apparent spectral distortion. Particularly, the uniformity of the large-area OLEDs was greatly improved. Theoretical calculation clarified that the improved performance of the lighting panels is primarily attributed to the effect of particle scattering.

Charts for the minimum-weight design of 24s-t aluminum-alloy flat compression panels with longitudinal z-section stiffeners

NASA Technical Reports Server (NTRS)

Schuette, Evan H

1945-01-01

Design charts are developed for 24s-t aluminum-alloy flat compression panels with longitudinal z-section stiffeners. These charts make possible the design of the lightest panels of this type for a wide range of design requirements. Examples of the use of the charts are given and it is pointed out on the basis of these examples that, over a wide range of design conditions, the maintenance of buckle-free surfaces does not conflict with the achievement of high structural efficiency. The achievement of the maximum possible structural efficiency with 24s-t aluminum-alloy panels, however, requires closer stiffener spacings than those now in common use.

Reliability of clinical guideline development using mail-only versus in-person expert panels.

PubMed

Washington, Donna L; Bernstein, Steven J; Kahan, James P; Leape, Lucian L; Kamberg, Caren J; Shekelle, Paul G

2003-12-01

Clinical practice guidelines quickly become outdated. One reason they might not be updated as often as needed is the expense of collecting expert judgment regarding the evidence. The RAND-UCLA Appropriateness Method is one commonly used method for collecting expert opinion. We tested whether a less expensive, mail-only process could substitute for the standard in-person process normally used. We performed a 4-way replication of the appropriateness panel process for coronary revascularization and hysterectomy, conducting 3 panels using the conventional in-person method and 1 panel entirely by mail. All indications were classified as inappropriate or not (to evaluate overuse), and coronary revascularization indications were classified as necessary or not (to evaluate underuse). Kappa statistics were calculated for the comparison in ratings from the 2 methods. Agreement beyond chance between the 2 panel methods ranged from moderate to substantial. The kappa statistic to detect overuse was 0.57 for coronary revascularization and 0.70 for hysterectomy. The kappa statistic to detect coronary revascularization underuse was 0.76. There were no cases in which coronary revascularization was considered inappropriate by 1 method, but necessary or appropriate by the other. Three of 636 (0.5%) hysterectomy cases were categorized as inappropriate by 1 method but appropriate by the other. The reproducibility of the overuse and underuse assessments from the mail-only compared with the conventional in-person conduct of expert panels in this application was similar to the underlying reproducibility of the process. This suggests a potential role for updating guidelines using an expert judgment process conducted entirely through the mail.

Design and fabrication of Rene 41 advanced structural panels. [their performance under axial compression, shear, and bending loads

NASA Technical Reports Server (NTRS)

Greene, B. E.; Northrup, R. F.

1975-01-01

The efficiency was investigated of curved elements in the design of lightweight structural panels under combined loads of axial compression, inplane shear, and bending. The application is described of technology generated in the initial aluminum program to the design and fabrication of Rene 41 panels for subsequent performance tests at elevated temperature. Optimum designs for two panel configurations are presented. The designs are applicable to hypersonic airplane wing structure, and are designed specifically for testing at elevated temperature in the hypersonic wing test structure located at the NASA Flight Research Center. Fabrication methods developed to produce the Rene panels are described, and test results of smaller structural element specimens are presented to verify the design and fabrication methods used. Predicted strengths of the panels under several proposed elevated temperature test load conditions are presented.

NASA Workshop on future directions in surface modeling and grid generation

NASA Technical Reports Server (NTRS)

Vandalsem, W. R.; Smith, R. E.; Choo, Y. K.; Birckelbaw, L. D.; Vogel, A. A.

1992-01-01

Given here is a summary of the paper sessions and panel discussions of the NASA Workshop on Future Directions in Surface Modeling and Grid Generation held a NASA Ames Research Center, Moffett Field, California, December 5-7, 1989. The purpose was to assess U.S. capabilities in surface modeling and grid generation and take steps to improve the focus and pace of these disciplines within NASA. The organization of the workshop centered around overviews from NASA centers and expert presentations from U.S. corporations and universities. Small discussion groups were held and summarized by group leaders. Brief overviews and a panel discussion by representatives from the DoD were held, and a NASA-only session concluded the meeting. In the NASA Program Planning Session summary there are five recommended steps for NASA to take to improve the development and application of surface modeling and grid generation.

Optical characterization of display screens by speckle patterns

NASA Astrophysics Data System (ADS)

Pozo, Antonio M.; Castro, José J.; Rubiño, Manuel

2013-10-01

In recent years, flat-panel display (FPD) technology has undergone great development, and now FPDs appear in many devices. A significant element in FPD manufacturing is the display front surface. Manufacturers sell FPDs with different types of front surfaces, which can be matte (also called anti-glare) or glossy screens. Users who prefer glossy screens consider these displays to show more vivid colors compared with matte-screen displays. However, on the glossy screens, external light sources may cause unpleasant reflections that can be reduced by a matte treatment in the front surface. In this work, we present a method to characterize FPD screens using laser-speckle patterns. We characterize three FPDs: a Samsung XL2370 LCD monitor of 23 in. with matte screen, a Toshiba Satellite A100 LCD laptop of 15.4 in. with glossy screen, and a Grammata Papyre 6.1 electronic book reader of 6 in. with ePaper screen (E-ink technology). The results show great differences in speckle-contrast values for the three screens characterized and, therefore, this work shows the feasibility of this method for characterizing and comparing FPDs that have different types of front surfaces.

Validation of Vehicle Panel/Equipment Response from Diffuse Acoustic Field Excitation Using Spatially Correlated Transfer Function Approach

NASA Technical Reports Server (NTRS)

Smith, Andrew; LaVerde, Bruce; Fulcher, Clay; Hunt, Ron

2012-01-01

An approach for predicting the vibration, strain, and force responses of a flight-like vehicle panel assembly to acoustic pressures is presented. Important validation for the approach is provided by comparison to ground test measurements in a reverberant chamber. The test article and the corresponding analytical model were assembled in several configurations to demonstrate the suitability of the approach for response predictions when the vehicle panel is integrated with equipment. Critical choices in the analysis necessary for convergence of the predicted and measured responses are illustrated through sensitivity studies. The methodology includes representation of spatial correlation of the pressure field over the panel surface. Therefore, it is possible to demonstrate the effects of hydrodynamic coincidence in the response. The sensitivity to pressure patch density clearly illustrates the onset of coincidence effects on the panel response predictions.

Method for making an aluminum or copper substrate panel for selective absorption of solar energy

NASA Technical Reports Server (NTRS)

Roberts, M. L.; Sharpe, M. H.; Krupnick, A. C. (Inventor)

1978-01-01

A panel is described for selectively absorbing solar energy comprising an aluminum substrate. A zinc layer was covered by a layer of nickel and an outer layer of solar energy absorbing nickel oxide or a copper substrate with a nickel layer. A layer of solar energy absorbing nickel oxide distal from the copper substrate was included. A method for making these panels is disclosed.

Solar-Array Substrate From Glass-Reinforced Concrete

NASA Technical Reports Server (NTRS)

Eirls, J. L.

1985-01-01

Design elminiates glass superstrate and associated metal framing. Panel has two trapezoidal stiffening ribs for structural support. Strategic placement of ribs with embedded support tubes (standard PVC tubing) minimizes bending moments and resulting stresses produced by installation and windloads. Glass-reinforced concrete panel has smooth flat surface suitable for solar substrate and includes structural bracing for rigidity and design adaptable to mass production.

Applications of random forest feature selection for fine-scale genetic population assignment.

PubMed

Sylvester, Emma V A; Bentzen, Paul; Bradbury, Ian R; Clément, Marie; Pearce, Jon; Horne, John; Beiko, Robert G

2018-02-01

Genetic population assignment used to inform wildlife management and conservation efforts requires panels of highly informative genetic markers and sensitive assignment tests. We explored the utility of machine-learning algorithms (random forest, regularized random forest and guided regularized random forest) compared with F ST ranking for selection of single nucleotide polymorphisms (SNP) for fine-scale population assignment. We applied these methods to an unpublished SNP data set for Atlantic salmon ( Salmo salar ) and a published SNP data set for Alaskan Chinook salmon ( Oncorhynchus tshawytscha ). In each species, we identified the minimum panel size required to obtain a self-assignment accuracy of at least 90% using each method to create panels of 50-700 markers Panels of SNPs identified using random forest-based methods performed up to 7.8 and 11.2 percentage points better than F ST -selected panels of similar size for the Atlantic salmon and Chinook salmon data, respectively. Self-assignment accuracy ≥90% was obtained with panels of 670 and 384 SNPs for each data set, respectively, a level of accuracy never reached for these species using F ST -selected panels. Our results demonstrate a role for machine-learning approaches in marker selection across large genomic data sets to improve assignment for management and conservation of exploited populations.

Characteristics of Indium Tin Oxide (ITO) Nanoparticles Recovered by Lift-off Method from TFT-LCD Panel Scraps.

PubMed

Choi, Dongchul; Hong, Sung-Jei; Son, Yongkeun

2014-11-27

In this study, indium-tin-oxide (ITO) nanoparticles were simply recovered from the thin film transistor-liquid crystal display (TFT-LCD) panel scraps by means of lift-off method. This can be done by dissolving color filter (CF) layer which is located between ITO layer and glass substrate. In this way the ITO layer was easily lifted off the glass substrate of the panel scrap without panel crushing. Over 90% of the ITO on the TFT-LCD panel was recovered by using this method. After separating, the ITO was obtained as particle form and their characteristics were investigated. The recovered product appeared as aggregates of particles less than 100 nm in size. The weight ratio of In/Sn is very close to 91/9. XRD analysis showed that the ITO nanoparticles have well crystallized structures with (222) preferred orientation even after recovery. The method described in this paper could be applied to the industrial recovery business for large size LCD scraps from TV easily without crushing the glass substrate.

Characteristics of Indium Tin Oxide (ITO) Nanoparticles Recovered by Lift-off Method from TFT-LCD Panel Scraps

PubMed Central

Choi, Dongchul; Hong, Sung-Jei; Son, Yongkeun

2014-01-01

In this study, indium-tin-oxide (ITO) nanoparticles were simply recovered from the thin film transistor-liquid crystal display (TFT-LCD) panel scraps by means of lift-off method. This can be done by dissolving color filter (CF) layer which is located between ITO layer and glass substrate. In this way the ITO layer was easily lifted off the glass substrate of the panel scrap without panel crushing. Over 90% of the ITO on the TFT-LCD panel was recovered by using this method. After separating, the ITO was obtained as particle form and their characteristics were investigated. The recovered product appeared as aggregates of particles less than 100 nm in size. The weight ratio of In/Sn is very close to 91/9. XRD analysis showed that the ITO nanoparticles have well crystallized structures with (222) preferred orientation even after recovery. The method described in this paper could be applied to the industrial recovery business for large size LCD scraps from TV easily without crushing the glass substrate. PMID:28788267

Experimental measurements of a prototype high-concentration Fresnel lens and sun-tracking method for photovoltaic panel's efficiency enhancement

NASA Astrophysics Data System (ADS)

Rajaee, Meraj; Ghorashi, Seyed Mohamad Bagher

2015-08-01

Concentrator photovoltaic modules are a promising technology for highly efficient solar energy conversion. This system presents several advantages due to additional degrees of freedom that has been provided by the spectral separation such as cost and mass reduction, increase in the incident solar flux on PV cells and performances. This paper has proposed a unique photovoltaic solar cell system that consists of semi-Fresnel lens convergent structure and a novel two axis sun tracking module to enhance the efficiency of solar cell by using less cell area and energy losses. The grooves of this lens are calculated according to the refraction and convergent angles of the light easy for perpendicular incidence angle. The update time interval during tracking causes misalignment of the lens' optical axis versus the sunrays. Then an inventive sun-tracking method is introduced to adjust the module so that the incident rays are always perpendicular to the module's surface. As a result, all rays will be refracted with the predetermined angles. This way the focus area is reduced and smaller cells can be used. We also mentioned different module connections in order to provide compensation method during losses, for networks and power systems. Experimental results show that using semi-Fresnel lens, along with the sun-tracking method increases the efficiency of PV panel.

A reductionist approach to extract robust molecular markers from microarray data series - Isolating markers to track osseointegration.

PubMed

Barik, Anwesha; Banerjee, Satarupa; Dhara, Santanu; Chakravorty, Nishant

2017-04-01

Complexities in the full genome expression studies hinder the extraction of tracker genes to analyze the course of biological events. In this study, we demonstrate the applications of supervised machine learning methods to reduce the irrelevance in microarray data series and thereby extract robust molecular markers to track biological processes. The methodology has been illustrated by analyzing whole genome expression studies on bone-implant integration (ossointegration). Being a biological process, osseointegration is known to leave a trail of genetic footprint during the course. In spite of existence of enormous amount of raw data in public repositories, researchers still do not have access to a panel of genes that can definitively track osseointegration. The results from our study revealed panels comprising of matrix metalloproteinases and collagen genes were able to track osseointegration on implant surfaces (MMP9 and COL1A2 on micro-textured; MMP12 and COL6A3 on superimposed nano-textured surfaces) with 100% classification accuracy, specificity and sensitivity. Further, our analysis showed the importance of the progression of the duration in establishment of the mechanical connection at bone-implant surface. The findings from this study are expected to be useful to researchers investigating osseointegration of novel implant materials especially at the early stage. The methodology demonstrated can be easily adapted by scientists in different fields to analyze large databases for other biological processes. Copyright © 2017 Elsevier Inc. All rights reserved.

Surface Science at the Solid Liquid Interface

DTIC Science & Technology

1993-10-06

prominent experimental avenue, developed originally by Hubbard et al,_ involves emersing monocrystalline elec- As for metal surfaces in ultrahigh vacuum...reliable means of both preparing and dosateizn ordered monocrystalline metal surfaces in UHV has led to ing appropriate molecular components of...surface atoms in place of bottom panel of Fig. 2, equal intensity contours are shown 23 underlying surface atoms, the compression is 24/23 - I in the

Nano-cone optical fiber array sensors for MiRNA profiling

NASA Astrophysics Data System (ADS)

Wang, Yunshan; Senapati, Satyajyoti; Stoddart, Paul; Howard, Scott; Chang, Hsueh-Chia

2013-09-01

Up/down regulation of microRNA panels has been correlated to cardiovascular diseases and cancer. Frequent miRNA profiling at home can hence allow early cancer diagnosis and home-use chronic disease monitoring, thus reducing both mortality rate and healthcare cost. However, lifetime of miRNAs is less than 1 hour without preservation and their concentrations range from pM to mM. Despite rapid progress in the last decade, modern nucleic acid analysis methods still do not allow personalized miRNA profiling---Real-time PCR and DNA micro-array both require elaborate miRNA preservation steps and expensive equipment and nano pore sensors cannot selectively quantify a large panel with a large dynamic range. We report a novel and low-cost optical fiber sensing platform, which has the potential to profile a panel of miRNA with simple LED light sources and detectors. The individual tips of an optical imaging fiber bundle (mm in diameter with 7000 fiber cores) were etched into cones with 10 nm radius of curvature and coated with Au. FRET (Forster Resonant Energy Transfer) hairpin oligo probes, with the loop complementary to a specific miRNA that can release the hairpin, were functionalized onto the conic tips. Exciting light in the optical fiber waveguide is optimally coupled to surface plasmonics on the gold surface, which then converges to the conic tips with two orders of magnitude enhancement in intensity. Unlike nanoparticle plasmonics, tip plasmonics can be excited over a large band width and hence the plasmonic enhanced fluorescence signal of the FRET reporter is also focused towards the tip--- and is further enhanced with the periodic resonant grid of the fiber array which gives rise to pronounced standing wave interference patterns. Multiplexing is realized by functionalizing different probes onto one fiber bundle using a photoactivation process.

Nanostructured refractory thin films for solar applications

NASA Astrophysics Data System (ADS)

Ollier, E.; Dunoyer, N.; Dellea, O.; Szambolics, H.

2014-08-01

Selective solar absorbers are key elements of all solar thermal systems. Solar thermal panels and Concentrated Solar Power (CSP) systems aim respectively at producing heat and electricity. In both cases, a surface receives the solar radiation and is designed to have the highest optical absorption (lowest optical reflectivity) of the solar radiation in the visible wavelength range where the solar intensity is the highest. It also has a low emissivity in the infrared (IR) range in order to avoid radiative thermal losses. Current solutions in the state of the art usually consist in deposited interferential thin films or in cermets [1]. Structured surfaces have been proposed and have been simulated because they are supposed to be more efficient when the solar radiation is not normal to the receiving surface and because they could potentially be fabricated with refractory materials able to sustain high operating temperatures. This work presents a new method to fabricate micro/nanostructured surfaces on molybdenum (refractory metal with a melting temperature of 2623°C). This method now allows obtaining a refractory selective surface with an excellent optical selectivity and a very high absorption in the visible range. This high absorption performance was obtained by achieving a double structuration at micro and nano scales thanks to an innovative process flow.

Solar panel truss mounting systems and methods

DOEpatents

Al-Haddad, Tristan Farris; Cavieres, Andres; Gentry, Russell; Goodman, Joseph; Nolan, Wade; Pitelka, Taylor; Rahimzadeh, Keyan; Brooks, Bradley; Lohr, Joshua; Crooks, Ryan; Porges, Jamie; Rubin, Daniel

2015-10-20

An exemplary embodiment of the present invention provides a solar panel truss mounting system comprising a base and a truss assembly coupled to the base. The truss assembly comprises a first panel rail mount, second panel rail mount parallel to the first panel rail mount, base rail mount parallel to the first and second panel rail mounts, and a plurality of support members. A first portion of the plurality of support members extends between the first and second panel rail mounts. A second portion of the plurality of support members extends between the first panel rail mount and the base rail mount. A third portion of the plurality of support members extends between the second panel rail mount and the base rail mount. The system can further comprise a plurality of connectors for coupling a plurality of photovoltaic solar panels to the truss assembly.

Solar panel truss mounting systems and methods

DOEpatents

Al-Haddad, Tristan Farris; Cavieres, Andres; Gentry, Russell; Goodman, Joseph; Nolan, Wade; Pitelka, Taylor; Rahimzadeh, Keyan; Brooks, Bradley; Lohr, Joshua; Crooks, Ryan; Porges, Jamie; Rubin, Daniel

2016-06-28

An exemplary embodiment of the present invention provides a solar panel truss mounting system comprising a base and a truss assembly coupled to the base. The truss assembly comprises a first panel rail mount, second panel rail mount parallel to the first panel rail mount, base rail mount parallel to the first and second panel rail mounts, and a plurality of support members. A first portion of the plurality of support members extends between the first and second panel rail mounts. A second portion of the plurality of support members extends between the first panel rail mount and the base rail mount. A third portion of the plurality of support members extends between the second panel rail mount and the base rail mount. The system can further comprise a plurality of connectors for coupling a plurality of photovoltaic solar panels to the truss assembly.

Orbiter radiator panel solar focusing test

NASA Technical Reports Server (NTRS)

Howell, H. R.; Rankin, J. G.

1983-01-01

Test data are presented which define the area around the Orbiter radiator panels for which the solar reflections are concentrated to one-sun or more. The concave shape of the panels and their specular silver/Teflon coating causes focusing of the reflected solar energy which could have adverse heating effects on equipment or astronaut extravehicular activity (EVA) in the vicinity of the radiator panels. A room ambient test method was utilized with a one-tenth scale model of the radiator panels.

Integral freeform illumination lens design of LED based pico-projector.

PubMed

Zhao, Shuang; Wang, Kai; Chen, Fei; Qin, Zong; Liu, Sheng

2013-05-01

In this paper, an illumination lens design for a LED-based pico-projector is presented. Different from the traditional illumination systems composed by lens group, the integral illumination lens consists of a total internal reflector (TIR) and a freeform surface. TIR acts as collimation lens and its top surface formed by a freeform surface reshapes the nonuniform circular light pattern generated by TIR to be rectangular and uniform. Diameter and height of the lens are 16 and 10 mm, respectively. An optimization method to deal with the problem of extended light source is also presented in detail in this paper. According to the simulation results of the final optimized lens, 77% (neglecting the effect of polarization) of the power of light source is collected on liquid crystal on silicon panel with a 16∶9 ratio and illumination uniformity achieves 92%.

A novel solution for LED wall lamp design and simulation

NASA Astrophysics Data System (ADS)

Ge, Rui; Hong, Weibin; Li, Kuangqi; Liang, Pengxiang; Zhao, Fuli

2014-11-01

The model of the wall washer lamp and the practical illumination application have been established with a new design of the lens to meet the uniform illumination demand for wall washer lamp based on the Lambertian light sources. Our secondary optical design of freeform surface lens to LED wall washer lamp based on the conservation law of energy and Snell's law can improve the lighting effects as a uniform illumination. With the relationship between the surface of the lens and the surface of the target, a great number of discrete points of the freeform profile curve were obtained through the iterative method. After importing the data into our modeling program, the optical entity was obtained. Finally, to verify the feasibility of the algorithm, the model was simulated by specialized software, with both the LED Lambertian point source and LED panel source model.

Size Effects in Impact Damage of Composite Sandwich Panels

NASA Technical Reports Server (NTRS)

Dobyns, Alan; Jackson, Wade

2003-01-01

Panel size has a large effect on the impact response and resultant damage level of honeycomb sandwich panels. It has been observed during impact testing that panels of the same design but different panel sizes will show large differences in damage when impacted with the same impact energy. To study this effect, a test program was conducted with instrumented impact testing of three different sizes of sandwich panels to obtain data on panel response and residual damage. In concert with the test program. a closed form analysis method was developed that incorporates the effects of damage on the impact response. This analysis method will predict both the impact response and the residual damage of a simply-supported sandwich panel impacted at any position on the panel. The damage is incorporated by the use of an experimental load-indentation curve obtained for the face-sheet/honeycomb and indentor combination under study. This curve inherently includes the damage response and can be obtained quasi-statically from a rigidly-backed specimen or a specimen with any support conditions. Good correlation has been obtained between the test data and the analysis results for the maximum force and residual indentation. The predictions can be improved by using a dynamic indentation curve. Analyses have also been done using the MSC/DYTRAN finite element code.

Prediction of vortex shedding from circular and noncircular bodies in supersonic flow

NASA Technical Reports Server (NTRS)

Mendenhall, M. R.; Perkins, S. C., Jr.

1984-01-01

An engineering prediction method and associated computer code NOZVTX to predict nose vortex shedding from circular and noncircular bodies in supersonic flow at angles of attack and roll are presented. The body is represented by either a supersonic panel method for noncircular cross sections or line sources and doublets for circular cross sections, and the lee side vortex wake is modeled by discrete vortices in crossflow planes. The three-dimensional steady flow problem is reduced to a two-dimensional, unsteady, separated flow problem for solution. Comparison of measured and predicted surface pressure distributions, flow field surveys, and aerodynamic characteristics is presented for bodies with circular and noncircular cross-sectional shapes.

Field testing and evaluation of a demonstration timber bridge.

DOT National Transportation Integrated Search

2012-02-01

Asphalt wearing surfaces are commonly used on timber bridges with transverse glued-laminated deck panel systems to help protect the timber components. However, poor performance of these asphalt wearing surfaces in the past has resulted in repeated re...

Solid-perforated panel layout optimization by topology optimization based on unified transfer matrix.

PubMed

Kim, Yoon Jae; Kim, Yoon Young

2010-10-01

This paper presents a numerical method for the optimization of the sequencing of solid panels, perforated panels and air gaps and their respective thickness for maximizing sound transmission loss and/or absorption. For the optimization, a method based on the topology optimization formulation is proposed. It is difficult to employ only the commonly-used material interpolation technique because the involved layers exhibit fundamentally different acoustic behavior. Thus, an optimization method formulation using a so-called unified transfer matrix is newly proposed. The key idea is to form elements of the transfer matrix such that interpolated elements by the layer design variables can be those of air, perforated and solid panel layers. The problem related to the interpolation is addressed and bench mark-type problems such as sound transmission or absorption maximization problems are solved to check the efficiency of the developed method.

PAN AIR: A computer program for predicting subsonic or supersonic linear potential flows about arbitrary configurations using a higher order panel method. Volume 1: Theory document (version 3.0)

NASA Technical Reports Server (NTRS)

Epton, Michael A.; Magnus, Alfred E.

1990-01-01

An outline of the derivation of the differential equation governing linear subsonic and supersonic potential flow is given. The use of Green's Theorem to obtain an integral equation over the boundary surface is discussed. The engineering techniques incorporated in the Panel Aerodynamics (PAN AIR) program (a discretization method which solves the integral equation for arbitrary first order boundary conditions) are then discussed in detail. Items discussed include the construction of the compressibility transformation, splining techniques, imposition of the boundary conditions, influence coefficient computation (including the concept of the finite part of an integral), computation of pressure coefficients, and computation of forces and moments. Principal revisions to version 3.0 are the following: (1) appendices H and K more fully describe the Aerodynamic Influence Coefficient (AIC) construction; (2) appendix L now provides a complete description of the AIC solution process; (3) appendix P is new and discusses the theory for the new FDP module (which calculates streamlines and offbody points); and (4) numerous small corrections and revisions reflecting the MAG module rewrite.

Line Scanning Thermography for Rapid Nondestructive Inspection of Large Scale Composites

NASA Astrophysics Data System (ADS)

Chung, S.; Ley, O.; Godinez, V.; Bandos, B.

2011-06-01

As next generation structures are utilizing larger amounts of composite materials, a rigorous and reliable method is needed to inspect these structures in order to prevent catastrophic failure and extend service life. Current inspection methods, such as ultrasonic, generally require extended down time and man hours as they are typically carried out via point-by-point measurements. A novel Line Scanning Thermography (LST) System has been developed for the non-contact, large-scale field inspection of composite structures with faster scanning times than conventional thermography systems. LST is a patented dynamic thermography technique where the heat source and thermal camera move in tandem, which allows the continuous scan of long surfaces without the loss of resolution. The current system can inspect an area of 10 in2 per 1 second, and has a resolution of 0.05×0.03 in2. Advanced data gathering protocols have been implemented for near-real time damage visualization and post-analysis algorithms for damage interpretation. The system has been used to successfully detect defects (delamination, dry areas) in fiber-reinforced composite sandwich panels for Navy applications, as well as impact damage in composite missile cases and armor ceramic panels.

Improved Aerodynamic Analysis for Hybrid Wing Body Conceptual Design Optimization

NASA Technical Reports Server (NTRS)

Gern, Frank H.

2012-01-01

This paper provides an overview of ongoing efforts to develop, evaluate, and validate different tools for improved aerodynamic modeling and systems analysis of Hybrid Wing Body (HWB) aircraft configurations. Results are being presented for the evaluation of different aerodynamic tools including panel methods, enhanced panel methods with viscous drag prediction, and computational fluid dynamics. Emphasis is placed on proper prediction of aerodynamic loads for structural sizing as well as viscous drag prediction to develop drag polars for HWB conceptual design optimization. Data from transonic wind tunnel tests at the Arnold Engineering Development Center s 16-Foot Transonic Tunnel was used as a reference data set in order to evaluate the accuracy of the aerodynamic tools. Triangularized surface data and Vehicle Sketch Pad (VSP) models of an X-48B 2% scale wind tunnel model were used to generate input and model files for the different analysis tools. In support of ongoing HWB scaling studies within the NASA Environmentally Responsible Aviation (ERA) program, an improved finite element based structural analysis and weight estimation tool for HWB center bodies is currently under development. Aerodynamic results from these analyses are used to provide additional aerodynamic validation data.

Low noise wing slat system with rigid cove-filled slat

NASA Technical Reports Server (NTRS)

Shmilovich, Arvin (Inventor); Yadlin, Yoram (Inventor)

2013-01-01

Concepts and technologies described herein provide for a low noise aircraft wing slat system. According to one aspect of the disclosure provided herein, a cove-filled wing slat is used in conjunction with a moveable panel rotatably attached to the wing slat to provide a high lift system. The moveable panel rotates upward against the rear surface of the slat during deployment of the slat, and rotates downward to bridge a gap width between the stowed slat and the lower wing surface, completing the continuous outer mold line shape of the wing, when the cove-filled slat is retracted to the stowed position.

KSC-2013-4176

NASA Image and Video Library

2013-11-19

CAPE CANAVERAL, Fla. -- At Launch Pad 39B at NASA’s Kennedy Space Center in Florida, all of the old crawler track panels have been removed from the surface and construction workers are repairing the concrete surface and catacomb roof below. New crawler track panels will be installed. Launch Pad 39B is being refurbished to support NASA’s Space Launch System and other launch vehicles. The Ground Systems Development and Operations, or GSDO, Program office at Kennedy is leading the center’s transformation to safely handle a variety of rockets and spacecraft. For more information about GSDO, visit: http://go.nasa.gov/groundsystems. Photo credit: NASA/Kim Shiflett

KSC-2013-4174

NASA Image and Video Library

2013-11-19

CAPE CANAVERAL, Fla. -- At Launch Pad 39B at NASA’s Kennedy Space Center in Florida, all of the old crawler track panels have been removed from the surface and construction workers are repairing the concrete surface and catacomb roof below. New crawler track panels will be installed. Launch Pad 39B is being refurbished to support NASA’s Space Launch System and other launch vehicles. The Ground Systems Development and Operations, or GSDO, Program office at Kennedy is leading the center’s transformation to safely handle a variety of rockets and spacecraft. For more information about GSDO, visit: http://go.nasa.gov/groundsystems. Photo credit: NASA/Kim Shiflett