European display scene

NASA Astrophysics Data System (ADS)

Bartlett, Christopher T.

2000-08-01

The manufacture of Flat Panel Displays (FPDs) is dominated by Far Eastern sources, particularly in Active Matrix Liquid Crystal Displays (AMLCD) and Plasma. The United States has a very powerful capability in micro-displays. It is not well known that Europe has a very active research capability which has lead to many innovations in display technology. In addition there is a capability in display manufacturing of organic technologies as well as the licensed build of Japanese or Korean designs. Finally, Europe has a display systems capability in military products which is world class.

New ASTM Standards for Nondestructive Testing of Aerospace Composites

NASA Technical Reports Server (NTRS)

Waller, Jess M.; Saulsberry, Regor L.

2010-01-01

Problem: Lack of consensus standards containing procedural detail for NDE of polymer matrix composite materials: I. Flat panel composites. II. Composite components with more complex geometries a) Pressure vessels: 1) composite overwrapped pressure vessels (COPVs). 2) composite pressure vessels (CPVs). III. Sandwich core constructions. Metal and brittle matrix composites are a possible subject of future effort.

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.

Matrix formalism of electromagnetic wave propagation through multiple layers in the near-field region: application to the flat panel display.

PubMed

Lee, C Y; Lee, D E; Hong, Y K; Shim, J H; Jeong, C K; Joo, J; Zang, D S; Shim, M G; Lee, J J; Cha, J K; Yang, H G

2003-04-01

We have developed an electromagnetic (EM) wave propagation theory through a single layer and multiple layers in the near-field and far-field regions, and have constructed a matrix formalism in terms of the boundary conditions of the EM waves. From the shielding efficiency (SE) against EM radiation in the near-field region calculated by using the matrix formalism, we propose that the effect of multiple layers yields enhanced shielding capability compared to a single layer with the same total thickness in conducting layers as the multiple layers. We compare the intensities of an EM wave propagating through glass coated with conducting indium tin oxide (ITO) on one side and on both sides, applying it to the electromagnetic interference (EMI) shielding filter in a flat panel display such as a plasma display panel (PDP). From the measured intensities of EMI noise generated by a PDP loaded with ITO coated glass samples, the two-side coated glass shows a lower intensity of EMI noise compared to the one-side coated glass. The result confirms the enhancement of the SE due to the effect of multiple layers, as expected in the matrix formalism of EM wave propagation in the near-field region. In the far-field region, the two-side coated glass with ITO in multiple layers has a higher SE than the one-side coated glass with ITO, when the total thickness of ITO in both cases is the same.

Flat-panel electronic displays: a triumph of physics, chemistry and engineering

PubMed Central

Hilsum, Cyril

2010-01-01

This paper describes the history and science behind the development of modern flat-panel displays, and assesses future trends. Electronic displays are an important feature of modern life. For many years the cathode ray tube, an engineering marvel, was universal, but its shape was cumbersome and its operating voltage too high. The need for a flat-panel display, working at a low voltage, became imperative, and much research has been applied to this need. Any versatile flat-panel display will exploit an electro-optical effect, a transparent conductor and an addressing system to deliver data locally. The first need is to convert an electrical signal into a visible change. Two methods are available, the first giving emission of light, the second modulating ambient illumination. The most useful light-emitting media are semiconductors, historically exploiting III–V or II–VI compounds, but more recently organic or polymer semiconductors. Another possible effect uses gas plasma discharges. The modulating, or subtractive, effects that have been studied include liquid crystals, electrophoresis, electrowetting and electrochromism. A transparent conductor makes it possible to apply a voltage to an extended area while observing the results. The design is a compromise, since the free electrons that carry current also absorb light. The first materials used were metals, but some semiconductors, when heavily doped, give a better balance, with high transmission for a low resistance. Delivering data unambiguously to a million or so picture elements across the display area is no easy task. The preferred solution is an amorphous silicon thin-film transistor deposited at each cross-point in an X–Y matrix. Success in these endeavours has led to many applications for flat-panel displays, including television, flexible displays, electronic paper, electronic books and advertising signs. PMID:20123746

Flat-panel electronic displays: a triumph of physics, chemistry and engineering.

PubMed

Hilsum, Cyril

2010-03-13

This paper describes the history and science behind the development of modern flat-panel displays, and assesses future trends. Electronic displays are an important feature of modern life. For many years the cathode ray tube, an engineering marvel, was universal, but its shape was cumbersome and its operating voltage too high. The need for a flat-panel display, working at a low voltage, became imperative, and much research has been applied to this need. Any versatile flat-panel display will exploit an electro-optical effect, a transparent conductor and an addressing system to deliver data locally. The first need is to convert an electrical signal into a visible change. Two methods are available, the first giving emission of light, the second modulating ambient illumination. The most useful light-emitting media are semiconductors, historically exploiting III-V or II-VI compounds, but more recently organic or polymer semiconductors. Another possible effect uses gas plasma discharges. The modulating, or subtractive, effects that have been studied include liquid crystals, electrophoresis, electrowetting and electrochromism. A transparent conductor makes it possible to apply a voltage to an extended area while observing the results. The design is a compromise, since the free electrons that carry current also absorb light. The first materials used were metals, but some semiconductors, when heavily doped, give a better balance, with high transmission for a low resistance. Delivering data unambiguously to a million or so picture elements across the display area is no easy task. The preferred solution is an amorphous silicon thin-film transistor deposited at each cross-point in an X-Y matrix. Success in these endeavours has led to many applications for flat-panel displays, including television, flexible displays, electronic paper, electronic books and advertising signs.

Flutter of Hybrid Laminated Flat Panels with Simply Supported Edges in Supersonic Flow

NASA Astrophysics Data System (ADS)

Barai, A.; Durvasula, S.

1994-01-01

Flutter of hybrid laminated flat panels in supersonic flow is studied by using first order shear deformation theory in conjunction with the assumed mode method. Both the quasi-static approximation and piston theory are used for aerodynamic force calculations at supersonic speeds. The flutter stability boundaries are determined by using the frequency coalescence criterion with the quasi-static approximation and Movchan-Krumhaar's criterion with the piston theory aerodynamics. Numerical calculations are presented for hybrid laminates consisting of graphite, Kevlar and glass fibres in an epoxy matrix. The effects of hybridization, shear deformation, ply orientation and aspect ratio are studied. The critical dynamic pressure parameter of a hybrid laminate lies between the values for laminates made with all plies of higher stiffness and with all plies of lower stiffness, respectively. The role of aerodynamic damping is found to be particularly important in determining the aeroelastic stability boundaries of laminated composite panels. Shear flexibility reduces the critical dynamic pressure parameter, but the reduction is insignificant for thin panels.

Amorphous silicon thin film transistor active-matrix organic light-emitting diode displays fabricated on flexible substrates

NASA Astrophysics Data System (ADS)

Nichols, Jonathan A.

Organic light-emitting diode (OLED) displays are of immense interest because they have several advantages over liquid crystal displays, the current dominant flat panel display technology. OLED displays are emissive and therefore are brighter, have a larger viewing angle, and do not require backlights and filters, allowing thinner, lighter, and more power efficient displays. The goal of this work was to advance the state-of-the-art in active-matrix OLED display technology. First, hydrogenated amorphous silicon (a-Si:H) thin film transistor (TFT) active-matrix OLED pixels and arrays were designed and fabricated on glass substrates. The devices operated at low voltages and demonstrated that lower performance TFTs could be utilized in active-matrix OLED displays, possibly allowing lower cost processing and the use of polymeric substrates. Attempts at designing more control into the display at the pixel level were also made. Bistable (one bit gray scale) active-matrix OLED pixels and arrays were designed and fabricated. Such pixels could be used in novel applications and eventually help reduce the bandwidth requirements in high-resolution and large-area displays. Finally, a-Si:H TFT active-matrix OLED pixels and arrays were fabricated on a polymeric substrate. Displays fabricated on a polymeric substrates would be lightweight; flexible, more rugged, and potentially less expensive to fabricate. Many of the difficulties associated with fabricating active-matrix backplanes on flexible substrates were studied and addressed.

A Laboratory-Based Course in Display Technology

ERIC Educational Resources Information Center

Sarik, J.; Akinwande, A. I.; Kymissis, I.

2011-01-01

A laboratory-based class in flat-panel display technology is presented. The course introduces fundamental concepts of display systems and reinforces these concepts through the fabrication of three display devices--an inorganic electroluminescent seven-segment display, a dot-matrix organic light-emitting diode (OLED) display, and a dot-matrix…

Projection display technologies for the new millennium

NASA Astrophysics Data System (ADS)

Kahn, Frederic J.

2000-04-01

Although analog CRTs continue to enable most of the world's electronic projection displays such as US consumer rear projection televisions, discrete pixel (digital) active matrix LCD and DLP reflective mirror array projectors have rapidly created large nonconsumer markets--primarily for business. Recent advances in image quality, compactness and cost effectiveness of digital projectors have the potential to revolutionize major consumer and entertainment markets as well. Digital penetration of the mainstream consumer projection TV market will begin in the hear 2000. By 2005 digital projection HDTVs could take the major share of the consumer HDTV projection market. Digital projection is expected to dominate both the consumer HDTV and the cinema market by 2010, resulting in potential shipments for all projection markets exceeding 10 M units per year. Digital projection is improving at a rate 10X faster than analog CRT projectors and 5X faster than PDP flat panels. Continued rapid improvement of digital projection is expected due to its relative immaturity and due to the wide diversity of technological improvements being pursued. Key technology enablers are the imaging panels, light sources and micro-optics. Market shares of single panel projectors, MEMs panels, LCOS panels and low T p-Si TFT LCD panel variants are expected to increase.

Display technologies; Proceedings of the Meeting, National Chiao Tung Univ., Hsinchu, Taiwan, Dec. 17, 18, 1992

NASA Astrophysics Data System (ADS)

Chen, Shu-Hsia; Wu, Shin-Tson

1992-10-01

A broad range of interdisciplinary subjects related to display technologies is addressed, with emphasis on high-definition displays, CRTs, projection displays, materials for display application, flat-panel displays, display modeling, and polymer-dispersed liquid crystals. Particular attention is given to a CRT approach to high-definition television display, a superhigh-resolution electron gun for color display CRT, a review of active-matrix liquid-crystal displays, color design for LCD parameters in projection and direct-view applications, annealing effects on ZnS:TbF3 electroluminescent devices prepared by RF sputtering, polycrystalline silicon thin film transistors with low-temperature gate dielectrics, refractive index dispersions of liquid crystals, a new rapid-response polymer-dispersed liquid-crystal material, and improved liquid crystals for active-matrix displays using high-tilt-orientation layers. (No individual items are abstracted in this volume)

Method of fabrication of display pixels driven by silicon thin film transistors

DOEpatents

Carey, Paul G.; Smith, Patrick M.

1999-01-01

Display pixels driven by silicon thin film transistors are fabricated on plastic substrates for use in active matrix displays, such as flat panel displays. The process for forming the pixels involves a prior method for forming individual silicon thin film transistors on low-temperature plastic substrates. Low-temperature substrates are generally considered as being incapable of withstanding sustained processing temperatures greater than about 200.degree. C. The pixel formation process results in a complete pixel and active matrix pixel array. A pixel (or picture element) in an active matrix display consists of a silicon thin film transistor (TFT) and a large electrode, which may control a liquid crystal light valve, an emissive material (such as a light emitting diode or LED), or some other light emitting or attenuating material. The pixels can be connected in arrays wherein rows of pixels contain common gate electrodes and columns of pixels contain common drain electrodes. The source electrode of each pixel TFT is connected to its pixel electrode, and is electrically isolated from every other circuit element in the pixel array.

Testing of DLR C/C-SiC for HIFiRE 8 Scramjet Combustor

NASA Technical Reports Server (NTRS)

Glass, David E.; Capriotti, Diego P.; Reimer, Thomas; Kutemeyer, Marius; Smart, Michael

2013-01-01

Ceramic Matrix Composites (CMCs) have been proposed for 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 C/C and a C/C-SiC material system fabricated by DLR (Stuttgart, Germany) are being considered for use in a passively cooled combustor design for HIFiRE 8, a joint Australia / AFRL hypersonic flight program, expected to fly at Mach 7 for approximately 30 sec, at a dynamic pressure of 55 kPa. Flat panels of the DLR C/C and the C/C-SiC were tested in the NASA Langley Direct Connect Rig (DCR) at Mach 5 and Mach 6 enthalpy for several minutes. 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 in some of the tests to increase the surface temperature of the C/C-SiC panel for approximately 350degF. The final C/C-SiC panel was tested for 3 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.

[Investigation of the accurate measurement of the basic imaging properties for the digital radiographic system based on flat panel detector].

PubMed

Katayama, R; Sakai, S; Sakaguchi, T; Maeda, T; Takada, K; Hayabuchi, N; Morishita, J

2008-07-20

PURPOSE/AIM OF THE EXHIBIT: The purpose of this exhibit is: 1. To explain "resampling", an image data processing, performed by the digital radiographic system based on flat panel detector (FPD). 2. To show the influence of "resampling" on the basic imaging properties. 3. To present accurate measurement methods of the basic imaging properties of the FPD system. 1. The relationship between the matrix sizes of the output image and the image data acquired on FPD that automatically changes depending on a selected image size (FOV). 2. The explanation of the image data processing of "resampling". 3. The evaluation results of the basic imaging properties of the FPD system using two types of DICOM image to which "resampling" was performed: characteristic curves, presampled MTFs, noise power spectra, detective quantum efficiencies. CONCLUSION/SUMMARY: The major points of the exhibit are as follows: 1. The influence of "resampling" should not be disregarded in the evaluation of the basic imaging properties of the flat panel detector system. 2. It is necessary for the basic imaging properties to be measured by using DICOM image to which no "resampling" is performed.

Scintillator high-gain avalanche rushing photoconductor active-matrix flat panel imager: Zero-spatial frequency x-ray imaging properties of the solid-state SHARP sensor structure

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

Wronski, M.; Zhao, W.; Tanioka, K.

Purpose: The authors are investigating the feasibility of a new type of solid-state x-ray imaging sensor with programmable avalanche gain: scintillator high-gain avalanche rushing photoconductor active matrix flat panel imager (SHARP-AMFPI). The purpose of the present work is to investigate the inherent x-ray detection properties of SHARP and demonstrate its wide dynamic range through programmable gain. Methods: A distributed resistive layer (DRL) was developed to maintain stable avalanche gain operation in a solid-state HARP. The signal and noise properties of the HARP-DRL for optical photon detection were investigated as a function of avalanche gain both theoretically and experimentally, and themore » results were compared with HARP tube (with electron beam readout) used in previous investigations of zero spatial frequency performance of SHARP. For this new investigation, a solid-state SHARP x-ray image sensor was formed by direct optical coupling of the HARP-DRL with a structured cesium iodide (CsI) scintillator. The x-ray sensitivity of this sensor was measured as a function of avalanche gain and the results were compared with the sensitivity of HARP-DRL measured optically. The dynamic range of HARP-DRL with variable avalanche gain was investigated for the entire exposure range encountered in radiography/fluoroscopy (R/F) applications. Results: The signal from HARP-DRL as a function of electric field showed stable avalanche gain, and the noise associated with the avalanche process agrees well with theory and previous measurements from a HARP tube. This result indicates that when coupled with CsI for x-ray detection, the additional noise associated with avalanche gain in HARP-DRL is negligible. The x-ray sensitivity measurements using the SHARP sensor produced identical avalanche gain dependence on electric field as the optical measurements with HARP-DRL. Adjusting the avalanche multiplication gain in HARP-DRL enabled a very wide dynamic range which encompassed all clinically relevant medical x-ray exposures. Conclusions: This work demonstrates that the HARP-DRL sensor enables the practical implementation of a SHARP solid-state x-ray sensor capable of quantum noise limited operation throughout the entire range of clinically relevant x-ray exposures. This is an important step toward the realization of a SHARP-AMFPI x-ray flat-panel imager.« less

Thin glass substrates for mobile applications

NASA Astrophysics Data System (ADS)

Mauch, Reiner H.; Wegener, Holger; Kruse, Anke; Hildebrand, Norbert

2000-10-01

Flat panel displays play an important role as the visual interface for today's electronic devices (Notebook computers, PDA's, pagers, mobile phones, etc.). Liquid Crystal Display's are dominating the market. While for higher resolution displays active matrix displays like Thin Film Transistor LCD's are used, portable devices are mainly using Super Twisted Nematic (STN) displays. Based on the application, STN displays for mobile applications require thinner glass substrates with improved surface quality at a lower cost. The requirements and trends for STN glass substrates are identified and discussed. Different glass manufacturing processes are used today for the manufacture of these substrates. Advantages and disadvantages of the different glass substrate types are presented and discussed.

75 FR 51286 - Certain Flat Panel Digital Televisions and Components Thereof; Notice of Investigation

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-19

... INTERNATIONAL TRADE COMMISSION [Inv. No. 337-TA-733] Certain Flat Panel Digital Televisions and... importation, and the sale within the United States after importation of certain flat panel digital televisions... after importation of certain flat panel digital televisions and components thereof that infringe one or...

Use and imaging performance of CMOS flat panel imager with LiF/ZnS(Ag) and Gadox scintillation screens for neutron radiography

NASA Astrophysics Data System (ADS)

Cha, B. K.; kim, J. Y.; Kim, T. J.; Sim, C.; Cho, G.; Lee, D. H.; Seo, C.-W.; Jeon, S.; Huh, Y.

2011-01-01

In digital neutron radiography system, a thermal neutron imaging detector based on neutron-sensitive scintillating screens with CMOS(complementary metal oxide semiconductor) flat panel imager is introduced for non-destructive testing (NDT) application. Recently, large area CMOS APS (active-pixel sensor) in conjunction with scintillation films has been widely used in many digital X-ray imaging applications. Instead of typical imaging detectors such as image plates, cooled-CCD cameras and amorphous silicon flat panel detectors in combination with scintillation screens, we tried to apply a scintillator-based CMOS APS to neutron imaging detection systems for high resolution neutron radiography. In this work, two major Gd2O2S:Tb and 6LiF/ZnS:Ag scintillation screens with various thickness were fabricated by a screen printing method. These neutron converter screens consist of a dispersion of Gd2O2S:Tb and 6LiF/ZnS:Ag scintillating particles in acrylic binder. These scintillating screens coupled-CMOS flat panel imager with 25x50mm2 active area and 48μm pixel pitch was used for neutron radiography. Thermal neutron flux with 6x106n/cm2/s was utilized at the NRF facility of HANARO in KAERI. The neutron imaging characterization of the used detector was investigated in terms of relative light output, linearity and spatial resolution in detail. The experimental results of scintillating screen-based CMOS flat panel detectors demonstrate possibility of high sensitive and high spatial resolution imaging in neutron radiography system.

A reduced-order integral formulation to account for the finite size effect of isotropic square panels using the transfer matrix method.

PubMed

Bonfiglio, Paolo; Pompoli, Francesco; Lionti, Riccardo

2016-04-01

The transfer matrix method is a well-established prediction tool for the simulation of sound transmission loss and the sound absorption coefficient of flat multilayer systems. Much research has been dedicated to enhancing the accuracy of the method by introducing a finite size effect of the structure to be simulated. The aim of this paper is to present a reduced-order integral formulation to predict radiation efficiency and radiation impedance for a panel with equal lateral dimensions. The results are presented and discussed for different materials in terms of radiation efficiency, sound transmission loss, and the sound absorption coefficient. Finally, the application of the proposed methodology for rectangular multilayer systems is also investigated and validated against experimental data.

75 FR 51285 - In the Matter of Certain Flat Panel Digital Televisions and Components Thereof; Notice of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-19

... INTERNATIONAL TRADE COMMISSION [Inv. No. 337-TA-733] In the Matter of Certain Flat Panel Digital... importation, and the sale within the United States after importation of certain flat panel digital televisions... sale within the United States after importation of certain flat panel digital televisions and...

An Analysis of Nondestructive Evaluation Techniques for Polymer Matrix Composite Sandwich Materials

NASA Technical Reports Server (NTRS)

Cosgriff, Laura M.; Roberts, Gary D.; Binienda, Wieslaw K.; Zheng, Diahua; Averbeck, Timothy; Roth, Donald J.; Jeanneau, Philippe

2006-01-01

Structural sandwich materials composed of triaxially braided polymer matrix composite material face sheets sandwiching a foam core are being utilized for applications including aerospace components and recreational equipment. Since full scale components are being made from these sandwich materials, it is necessary to develop proper inspection practices for their manufacture and in-field use. Specifically, nondestructive evaluation (NDE) techniques need to be investigated for analysis of components made from these materials. Hockey blades made from sandwich materials and a flat sandwich sample were examined with multiple NDE techniques including thermographic, radiographic, and shearographic methods to investigate damage induced in the blades and flat panel components. Hockey blades used during actual play and a flat polymer matrix composite sandwich sample with damage inserted into the foam core were investigated with each technique. NDE images from the samples were presented and discussed. Structural elements within each blade were observed with radiographic imaging. Damaged regions and some structural elements of the hockey blades were identified with thermographic imaging. Structural elements, damaged regions, and other material variations were detected in the hockey blades with shearography. Each technique s advantages and disadvantages were considered in making recommendations for inspection of components made from these types of materials.

Image quality and radiation dose on digital chest imaging: comparison of amorphous silicon and amorphous selenium flat-panel systems.

PubMed

Bacher, Klaus; Smeets, Peter; Vereecken, Ludo; De Hauwere, An; Duyck, Philippe; De Man, Robert; Verstraete, Koenraad; Thierens, Hubert

2006-09-01

The aim of this study was to compare the image quality and radiation dose in chest imaging using an amorphous silicon flat-panel detector system and an amorphous selenium flat-panel detector system. In addition, the low-contrast performance of both systems with standard and low radiation doses was compared. In two groups of 100 patients each, digital chest radiographs were acquired with either an amorphous silicon or an amorphous selenium flat-panel system. The effective dose of the examination was measured using thermoluminescent dosimeters placed in an anthropomorphic Rando phantom. The image quality of the digital chest radiographs was assessed by five experienced radiologists using the European Guidelines on Quality Criteria for Diagnostic Radiographic Images. In addition, a contrast-detail phantom study was set up to assess the low-contrast performance of both systems at different radiation dose levels. Differences between the two groups were tested for significance using the two-tailed Mann-Whitney test. The amorphous silicon flat-panel system allowed an important and significant reduction in effective dose in comparison with the amorphous selenium flat-panel system (p < 0.0001) for both the posteroanterior and lateral views. In addition, clinical image quality analysis showed that the dose reduction was not detrimental to image quality. Compared with the amorphous selenium flat-panel detector system, the amorphous silicon flat-panel detector system performed significantly better in the low-contrast phantom study, with phantom entrance dose values of up to 135 muGy. Chest radiographs can be acquired with a significantly lower patient radiation dose using an amorphous silicon flat-panel system than using an amorphous selenium flat-panel system, thereby producing images that are equal or even superior in quality to those of the amorphous selenium flat-panel detector system.

Flat-panel video resolution LED display system

NASA Astrophysics Data System (ADS)

Wareberg, P. G.; Kennedy, D. I.

The system consists of a 128 x 128 element X-Y addressable LED array fabricated from green-emitting gallium phosphide. The LED array is interfaced with a 128 x 128 matrix TV camera. Associated electronics provides for seven levels of grey scale above zero with a grey scale ratio of square root of 2. Picture elements are on 0.008 inch centers resulting in a resolution of 125 lines-per-inch and a display area of approximately 1 sq. in. The LED array concept lends itself to modular construction, permitting assembly of a flat panel screen of any desired size from 1 x 1 inch building blocks without loss of resolution. A wide range of prospective aerospace applications exist extending from helmet-mounted systems involving small dedicated arrays to multimode cockpit displays constructed as modular screens. High-resolution LED arrays are already used as CRT replacements in military film-marking reconnaissance applications.

Applications of AMLCDs in U.S. military cockpits

NASA Astrophysics Data System (ADS)

Michaels, Robert A.; Desjardins, Daniel D.; Daniels, Reginald; Hopper, Darrel G.

1996-05-01

Active matrix liquid crystal displays have become the flat panel technology of choice for new cockpits as well as for retrofits of existing ones. Systems such as F-22, F-18, F-16, and C-141 have already begun extensive development efforts over the last few years. More recently, JPATS, AH-64, P-3, KC-135, T-45, and T-38 have announced plans to use AMLCDs also. Because of the advantages that AMLCDs have to offer, the list of platforms that will implement them will continue to grow over the next several years. The Displays Branch in Wright Laboratory is continually analyzing current as well as potential programs. An update on this analysis program is presented.

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.

Solid-state flat panel imager with avalanche amorphous selenium

NASA Astrophysics Data System (ADS)

Scheuermann, James R.; Howansky, Adrian; Goldan, Amir H.; Tousignant, Olivier; Levéille, Sébastien; Tanioka, K.; Zhao, Wei

2016-03-01

Active matrix flat panel imagers (AMFPI) have become the dominant detector technology for digital radiography and fluoroscopy. For low dose imaging, electronic noise from the amorphous silicon thin film transistor (TFT) array degrades imaging performance. We have fabricated the first prototype solid-state AMFPI using a uniform layer of avalanche amorphous selenium (a-Se) photoconductor to amplify the signal to eliminate the effect of electronic noise. We have previously developed a large area solid-state avalanche a-Se sensor structure referred to as High Gain Avalanche Rushing Photoconductor (HARP) capable of achieving gains of 75. In this work we successfully deposited this HARP structure onto a 24 x 30 cm2 TFT array with a pixel pitch of 85 μm. An electric field (ESe) up to 105 Vμm-1 was applied across the a-Se layer without breakdown. Using the HARP layer as a direct detector, an X-ray avalanche gain of 15 +/- 3 was achieved at ESe = 105 Vμm-1. In indirect mode with a 150 μm thick structured CsI scintillator, an optical gain of 76 +/- 5 was measured at ESe = 105 Vμm-1. Image quality at low dose increases with the avalanche gain until the electronic noise is overcome at a constant exposure level of 0.76 mR. We demonstrate the success of a solid-state HARP X-ray imager as well as the largest active area HARP sensor to date.

Systematic development of input-quantum-limited fluoroscopic imagers based on active-matrix flat-panel technology

NASA Astrophysics Data System (ADS)

Antonuk, Larry E.; Zhao, Qihua; Su, Zhong; Yamamoto, Jin; El-Mohri, Youcef; Li, Yixin; Wang, Yi; Sawant, Amit R.

2004-05-01

The development of fluoroscopic imagers exhibiting performance that is primarily limited by the noise of the incident x-ray quanta, even at very low exposures, remains a highly desirable objective for active matrix flat-panel technology. Previous theoretical and empirical studies have indicated that promising strategies to acheiving this goal include the development of array designs incorporating improved optical collection fill factors, pixel-level amplifiers, or very high-gain photoconductors. Our group is pursuing all three strategies and this paper describes progress toward the systematic development of array designs involving the last approach. The research involved the iterative fabrication and evaluation of a series of prototype imagers incorporating a promising high-gain photoconductive material, mercuric iodide (HgI2). Over many cycles of photoconductor deposition and array evaluation, improvements ina variety of properties have been observed and remaining fundamental challenges have become apparent. For example, process compatibility between the deposited HgI2 and the arrays have been greatly improved, while preserving efficient, prompt signal extraction. As a result, x-ray sensitivities within a factor of two of the nominal limit associated with the single-crystal form of HgI2 have been observed at relatively low electric fields (~0.1 to 0.6 V/μm), for some iterations. In addition, for a number of iterations, performance targets for dark current stability and range of linearity have been met or exceeded. However, spotting of the array, due to localized chemical reactions, is still a concern. Moreover, the dark current, uniformity of pixel response, and degree of charge trapping, though markedly improved for some iterations, require further optimization. Furthermore, achieving the desired performance for all properties simultaneously remains an important goal. In this paper, a broad overview of the progress of the research will be presented, remaining challenges in the development of this photoconductive material will be outlined, and prospects for further improvement will be discussed.

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.

Predictive value of flat-panel CT for haemorrhagic transformations in patients with acute stroke treated with thrombectomy.

PubMed

Rouchaud, Aymeric; Pistocchi, Silvia; Blanc, Raphaël; Engrand, Nicolas; Bartolini, Bruno; Piotin, Michel

2014-03-01

Haemorrhagic transformations are pejorative for patients with acute ischaemic stroke (AIS). We estimated flat-panel CT performances to detect brain parenchymal hyperdense lesions immediately after mechanical thrombectomy directly on the angiography table in patients with AIS, and its ability to predict haemorrhagic transformation. We also evaluated an easy-reading protocol for post-procedure flat-panel CT evaluation by clinicians to enable them to determine the potential risk of haemorrhage. Two neuroradiologists retrospectively reviewed post-procedural flat-panel CT and 24 h follow-up imaging. We evaluated hyperdense lesions on flat-panel CT to predict the occurrence of haemorrhagic transformation within 24 h detected with conventional imaging. Of 63 patients, 60.3% presented post-procedural parenchymal hyperdensity and 54.0% had haemorrhagic transformation. Significantly more patients with hyperdense lesions on post-thrombectomy flat-panel CT presented haemorrhagic transformation (84.2% vs 8.0%; p<0.0001). No significant haemorrhagic transformations were detected for patients without parenchymal hyperdensity. Sensitivity and specificity of hyperdense lesions on flat-panel CT for the prediction of haemorrhagic transformation were 94.1% (80.3-99.3%) and 79.3% (60.3-92.0%), respectively. The positive and negative predictive values for the occurrence of haemorrhage were 84.2% (68.8-94.0%) and 92.0% (74.0-99.0%), respectively. For significant parenchymal haemorrhage type 2, sensitivity and negative predictive values were 100%. We observed good homogeneity between the different readers. Hyperdensity on post-procedural flat-panel CT was associated with a tendency for higher risk of death and lower risk of good clinical outcome. Flat-panel CT appears to be a good tool to detect brain parenchymal hyperdensities after mechanical thrombectomy in patients with AIS and to predict haemorrhagic transformation.

Recommendations resulting from the SPDS Community-Wide Workshop

NASA Technical Reports Server (NTRS)

1993-01-01

The Data Systems Panel identified three critical functionalities of a Space Physics Data System (SPDS): the delivery of self-documenting data, the existence of a matrix of translators between various standard formats (IDFS, CDF, netCDF, HDF, TENNIS, UCLA flat file, and FITS), and a network-based capability for browsing and examining inventory records for the system's data holdings. The recommendations resulting from the workshop include the philosophy, funding, and objectives of a SPDS. Access to quality data is seen as the most important objective by the Policy Panel, with curation and information about the data being integral parts of any accessible data set. The Data Issues Panel concluded that the SPDS can supply encouragement, guidelines, and ultimately provide a mechanism for financial support for data archiving, restoration, and curation. The Software Panel of the SPDS focused on defining the requirements and priorities for SPDS to support common data analysis and data visualization tools and packages.

The effects of long-duration space exposure on the mechanical properties of some carbon-reinforced resin matrix composites

NASA Technical Reports Server (NTRS)

Vyhnal, Richard F.

1993-01-01

Long Duration Exposure Facility (LDEF) Experiment A0175 involved the non-instrumented exposure of seven carbon-fiber reinforced resin-matrix advanced composite panels contained in two trays - A7 and A1. These two trays were located, respectively, on the leading and trailing faces of LDEF, obliquely oriented to the RAM (Row 9) and WAKE (Row 3) directions. The identity and location of the seven panels, which consisted of six flat laminates of the following material systems are shown: carbon/epoxy (T300/934), carbon/bismaleimide (T300/F178), and carbon/polyimide (C6000/LARC-160 and C6000/PMR-15), plus one bonded honeycomb sandwich panel (T300/934 face sheets and Nomex core) patterned after the Space Shuttle payload bay door construction. These material systems were selected to represent a range of then-available matrix resins which, by virtue of their differing polymer chemistry, could conceivably exhibit differing susceptibility to the low-earth orbit (LEO) environment. The principal exposure conditions of the LDEF environment at these tray locations are shown. Noteworthy to some of the observations discussed is the four-orders-of magnitude difference in the atomic oxygen (AO) fluence, which made a shallow incidence angle (approximately 22 deg) to Tray A7, while Tray A1 on the trailing face was essentially shielded from AO exposure. This evaluation focused on determining the individual and relative suitability of a variety of resin-matrix composite systems for long-term space structural applications. This was accomplished primarily by measuring and comparing a range of engineering mechanical properties on over 300 test coupons sectioned from the flight panels and from identical control panels, and tested at ambient and elevated temperatures. This testing was supported by limited physical characterization, involving visual examination of flight panel surface features, measurements of weight loss and warpage, and examination for changes in internal integrity (micro cracking, delamination) by ultrasonic c-scan and polished cross-sections.

Flat Panel Displays for Medical Monitoring Systems

DTIC Science & Technology

2001-10-25

filter prevents light from passing (figure 2). FLAT PANEL DISPLAYS FOR MEDICAL MONITORING SYSTEMS A. Cebrián, J. Millet , I. García Department of...The touch screen is placed over the flat panel display as a filter (figure 10) and allows user interfaces based in direct finger touch (figure 11

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...

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...

Field emitter displays for future avionics applications

NASA Astrophysics Data System (ADS)

Jones, Susan K.; Jones, Gary W.; Zimmerman, Steven M.; Blazejewski, Edward R.

1995-06-01

Field emitter array-based display technology offers CRT-like characteristics in a thin flat-panel display with many potential applications for vehicle-mounted, crew workstation, and helmet-mounted displays, as well as many other military and commercial applications. In addition to thinness, high brightness, wide viewing angle, wide temperature range, and low weight, field emitter array displays also offer potential advantages such as row-at-a-time matrix addressability and the ability to be segmented.

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.

Piezoceramic Actuator Placement for Acoustic Control of Panels

NASA Technical Reports Server (NTRS)

Bevan, Jeffrey S.; Turner, Travis L. (Technical Monitor)

2001-01-01

Optimum placement of multiple traditional piezoceramic actuators is determined for active structural acoustic control of flat panels. The structural acoustic response is determined using acoustic radiation filters and structural surface vibration characteristics. Linear Quadratic Regulator (LQR) control is utilized to determine the optimum state feedback gain for active structural acoustic control. The optimum actuator location is determined by minimizing the structural acoustic radiated noise using a modified genetic algorithm. Experimental tests are conducted and compared to analytical results. Anisotropic piezoceramic actuators exhibits enhanced performance when compared to traditional isotropic piezoceramic actuators. As a result of the inherent isotropy, these advanced actuators develop strain along the principal material axis. The orientation of anisotropic actuators is investigated on the effect of structural vibration and acoustic control of curved and flat panels. A fully coupled shallow shell finite element formulation is developed to include anisotropic piezoceramic actuators for shell structures.

Piezoceramic Actuator Placement for Acoustic Control of Panels

NASA Technical Reports Server (NTRS)

Bevan, Jeffrey S.

2000-01-01

Optimum placement of multiple traditional piezoceramic actuators is determined for active structural acoustic control of flat panels. The structural acoustic response is determined using acoustic radiation filters and structural surface vibration characteristics. Linear Quadratic Regulator (LQR) control is utilized to determine the optimum state feedback gain for active structural acoustic control. The optimum actuator location is determined by minimizing the structural acoustic radiated noise using a modified genetic algorithm. Experimental tests are conducted and compared to analytical results. Anisotropic piezoceramic actuators exhibit enhanced performance when compared to traditional isotropic piezoceramic actuators. As a result of the inherent isotropy, these advanced actuators develop strain along the principal material axis. The orientation of anisotropic actuators is investigated on the effect of structural vibration and acoustic control of curved and flat panels. A fully coupled shallow shell finite element formulation is developed to include anisotropic piezoceramic actuators for shell structures.

Evaluation of a metal artifacts reduction algorithm applied to postinterventional flat panel detector CT imaging.

PubMed

Stidd, D A; Theessen, H; Deng, Y; Li, Y; Scholz, B; Rohkohl, C; Jhaveri, M D; Moftakhar, R; Chen, M; Lopes, D K

2014-01-01

Flat panel detector CT images are degraded by streak artifacts caused by radiodense implanted materials such as coils or clips. A new metal artifacts reduction prototype algorithm has been used to minimize these artifacts. The application of this new metal artifacts reduction algorithm was evaluated for flat panel detector CT imaging performed in a routine clinical setting. Flat panel detector CT images were obtained from 59 patients immediately following cerebral endovascular procedures or as surveillance imaging for cerebral endovascular or surgical procedures previously performed. The images were independently evaluated by 7 physicians for metal artifacts reduction on a 3-point scale at 2 locations: immediately adjacent to the metallic implant and 3 cm away from it. The number of visible vessels before and after metal artifacts reduction correction was also evaluated within a 3-cm radius around the metallic implant. The metal artifacts reduction algorithm was applied to the 59 flat panel detector CT datasets without complications. The metal artifacts in the reduction-corrected flat panel detector CT images were significantly reduced in the area immediately adjacent to the implanted metal object (P = .05) and in the area 3 cm away from the metal object (P = .03). The average number of visible vessel segments increased from 4.07 to 5.29 (P = .1235) after application of the metal artifacts reduction algorithm to the flat panel detector CT images. Metal artifacts reduction is an effective method to improve flat panel detector CT images degraded by metal artifacts. Metal artifacts are significantly decreased by the metal artifacts reduction algorithm, and there was a trend toward increased vessel-segment visualization. © 2014 by American Journal of Neuroradiology.

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.

Stationary Digital Tomosynthesis System for Early Detection of Breast Tumors

DTIC Science & Technology

2011-05-01

selenium flat panel detector. Proc. SPIE 2005. 5745: p. 529-540 4. Kopans, D.B., Breast Imaging. 2 ed. 1997, New York Lippincott Williams and...same. 2005. 8. M. Bissonnette, et al. Digital breast tomosynthesis using an amorphous selenium flat panel detector. in Medical Imaging 2005...tomosynthesis system with selenium based flat panel detector. Proc of SPIE, Physics of Medical Imaging, 2005. 5745. 12

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%.

Performance comparison of an active matrix flat panel imager, computed radiography system, and a screen-film system at four standard radiation qualities.

PubMed

Monnin, P; Gutierrez, D; Bulling, S; Lepori, D; Valley, J F; Verdun, F R

2005-02-01

Four standard radiation qualities (from RQA 3 to RQA 9) were used to compare the imaging performance of a computed radiography (CR) system (general purpose and high resolution phosphor plates of a Kodak CR 9000 system), a selenium-based direct flat panel detector (Kodak Direct View DR 9000), and a conventional screen-film system (Kodak T-MAT L/RA film with a 3M Trimax Regular screen of speed 400) in conventional radiography. Reference exposure levels were chosen according to the manufacturer's recommendations to be representative of clinical practice (exposure index of 1700 for digital systems and a film optical density of 1.4). With the exception of the RQA 3 beam quality, the exposure levels needed to produce a mean digital signal of 1700 were higher than those needed to obtain a mean film optical density of 1.4. In spite of intense developments in the field of digital detectors, screen-film systems are still very efficient detectors for most of the beam qualities used in radiology. An important outcome of this study is the behavior of the detective quantum efficiency of the digital radiography (DR) system as a function of beam energy. The practice of users to increase beam energy when switching from a screen-film system to a CR system, in order to improve the compromise between patient dose and image quality, might not be appropriate when switching from screen-film to selenium-based DR systems.

The effect of oblique angle of sound incidence, realistic edge conditions, curvature and in-plane panel stresses on the noise reduction characteristics of general aviation type panels

NASA Technical Reports Server (NTRS)

Grosveld, F.; Lameris, J.; Dunn, D.

1979-01-01

Experiments and a theoretical analysis were conducted to predict the noise reduction of inclined and curved panels. These predictions are compared to the experimental results with reasonable agreement between theory and experiment for panels under an oblique angle of sound incidence. Theoretical as well as experimental results indicate a big increase in noise reduction when a flat test panel is curved. Further curving the panel slightly decreases the noise reduction. Riveted flat panels are shown to give a higher noise reduction in the stiffness-controlled frequency region, while bonded panels are superior in this region when the test panel is curved. Experimentally measured noise reduction characteristics of flat aluminum panels with uniaxial in-plane stresses are presented and discussed. These test results indicate an important improvement in the noise reduction of these panels in the frequency range below the fundamental panel/cavity frequency.

Performance of Emcore Third Generation CPV Modules in the Low Latitude Marine Environment of Hawaii

NASA Astrophysics Data System (ADS)

Hoffman, Richard; Buie, Damien; King, David; Glesne, Thomas

2011-12-01

Emcore third generation concentrating photovoltaic (CPV) modules were evaluated in the low latitude location of Kihei, Hawaii. For comparison, the best available monocrystalline silicon flat panel modules were included in both dual-axis tracked and fixed mount configurations. The daily DC uncorrected efficiency value for the CPV modules averaged over the six-month performance period was 25.9% compared to 16% to 17% for the flat panels. Higher daily energy was obtained from CPV modules than tracked flat panels when daily direct solar insolation was greater than 5 kWh/m2 and more than fixed mount flat panel when direct insolation was greater than 3 kWh/m2. The module energy conversion performance was demonstrated to be predictable using a parametric model developed by Sandia National Laboratory. Soiling accumulation on module entrance surface was surprisingly rapid in the local environment. Measured energy loss rate due to soiling were two to six times larger for CPV compared to flat panel losses.

Testing and analysis of flat and curved panels with multiple cracks

DOT National Transportation Integrated Search

1994-08-01

An experimental and analytical investigation of multiple cracking in various types of test specimens is described in this paper. The testing phase is comprised of a flat unstiffened panel series and curved stiffened and unstiffened panel series. The ...

Flat panel ferroelectric electron emission display system

DOEpatents

Sampayan, Stephen E.; Orvis, William J.; Caporaso, George J.; Wieskamp, Ted F.

1996-01-01

A device which can produce a bright, raster scanned or non-raster scanned image from a flat panel. Unlike many flat panel technologies, this device does not require ambient light or auxiliary illumination for viewing the image. Rather, this device relies on electrons emitted from a ferroelectric emitter impinging on a phosphor. This device takes advantage of a new electron emitter technology which emits electrons with significant kinetic energy and beam current density.

Modelling the drying of three-dimensional pulp moulded structures. Part II, Drying data obtained from flat panels using virgin and recycled paper fibre

Treesearch

John F. Hunt; Margit Tamasy-Bano; Heike Nyist

1999-01-01

A three-dimensional structural panel, called FPL Spaceboard, was developed at the USDA Forest Products Laboratory. Spaceboard panels have been formed using a variety of fibrous materials using either a wet- or dry-forming process. Geometrically, the panel departs from the traditional two-dimensional flat panel by integrally forming an array of perpendicular ribs and...

Self-aligned top-gate amorphous indium zinc oxide thin-film transistors exceeding low-temperature poly-Si transistor performance.

PubMed

Park, Jae Chul; Lee, Ho-Nyeon; Im, Seongil

2013-08-14

Thin-film transistor (TFT) is a key component of active-matrix flat-panel displays (AMFPDs). These days, the low-temperature poly silicon (LTPS) TFTs are to match with advanced AMFPDs such as the active matrix organic light-emitting diode (AMOLED) display, because of their high mobility for fast pixel switching. However, the manufacturing process of LTPS TFT is quite complicated, costly, and scale-limited. Amorphous oxide semiconductor (AOS) TFT technology is another candidate, which is as simple as that of conventioanl amorphous (a)-Si TFTs in fabrication but provides much superior device performances to those of a-Si TFTs. Hence, various AOSs have been compared with LTPS for active channel layer of the advanced TFTs, but have always been found to be relatively inferior to LTPS. In the present work, we clear the persistent inferiority, innovating the device performaces of a-IZO TFT by adopting a self-aligned coplanar top-gate structure and modifying the surface of a-IZO material. Herein, we demonstrate a high-performance simple-processed a-IZO TFT with mobility of ∼157 cm(2) V(-1) s(-1), SS of ∼190 mV dec(-1), and good bias/photostabilities, which overall surpass the performances of high-cost LTPS TFTs.

Micro-valve pump light valve display

DOEpatents

Yeechun Lee.

1993-01-19

A flat panel display incorporates a plurality of micro-pump light valves (MLV's) to form pixels for recreating an image. Each MLV consists of a dielectric drop sandwiched between substrates, at least one of which is transparent, a holding electrode for maintaining the drop outside a viewing area, and a switching electrode from accelerating the drop from a location within the holding electrode to a location within the viewing area. The sustrates may further define non-wetting surface areas to create potential energy barriers to assist in controlling movement of the drop. The forces acting on the drop are quadratic in nature to provide a nonlinear response for increased image contrast. A crossed electrode structure can be used to activate the pixels whereby a large flat panel display is formed without active driver components at each pixel.

Micro-valve pump light valve display

DOEpatents

Lee, Yee-Chun

1993-01-01

A flat panel display incorporates a plurality of micro-pump light valves (MLV's) to form pixels for recreating an image. Each MLV consists of a dielectric drop sandwiched between substrates, at least one of which is transparent, a holding electrode for maintaining the drop outside a viewing area, and a switching electrode from accelerating the drop from a location within the holding electrode to a location within the viewing area. The sustrates may further define non-wetting surface areas to create potential energy barriers to assist in controlling movement of the drop. The forces acting on the drop are quadratic in nature to provide a nonlinear response for increased image contrast. A crossed electrode structure can be used to activate the pixels whereby a large flat panel display is formed without active driver components at each pixel.

Radiation dose reduction in chest radiography using a flat-panel amorphous silicon detector.

PubMed

Hosch, W P; Fink, C; Radeleff, B; kampschulte a, A; Kauffmann, G W; Hansmann, J

2002-10-01

The aim of this study was to evaluate the image quality and the potential for radiation dose reduction with a digital flat-panel amorphous silicon detector radiography system. Using flat-panel technology, radiographs of an anthropomorphic thorax phantom were taken with a range of technical parameters (125kV, 200mA and 5, 4, 3.2, 2, 1, 0.5, and 0.25mAs) which were equivalent to a radiation dose of 332, 263, 209, 127, 58.7, 29, and 14 microGy, respectively. These images were compared to radiographs obtained by a conventional film-screen radiography system at 125kV, 200mA and 5mAs (equivalent to 252 microGy) which served as reference. Three observers evaluated independently the visibility of simulated rounded lesions and anatomical structures, comparing printed films from the flat-panel amorphous silicon detector and conventional x-ray system films. With flat-panel technology, the visibility of rounded lesions and normal anatomical structures at 5, 4, and 3.2mAs was superior compared to the conventional film-screen radiography system. (P< or =0.0001). At 2mAs, improvement was only marginal (P=0.19). At 1.0, 0.5 and 0.25mAs, the visibility of simulated rounded lesions was worse (P< or =0.004). Comparing fine lung parenchymal structures, the flat-panel amorphous silicon detector showed improvement for all exposure levels down to 2mAs and equality at 1mAs. Compared to a conventional x-ray film system, the flat-panel amorphous silicon detector demonstrated improved image quality and the possibility for a reduction of the radiation dose by 50% without loss in image quality.

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...

Flat panel ferroelectric electron emission display system

DOEpatents

Sampayan, S.E.; Orvis, W.J.; Caporaso, G.J.; Wieskamp, T.F.

1996-04-16

A device is disclosed which can produce a bright, raster scanned or non-raster scanned image from a flat panel. Unlike many flat panel technologies, this device does not require ambient light or auxiliary illumination for viewing the image. Rather, this device relies on electrons emitted from a ferroelectric emitter impinging on a phosphor. This device takes advantage of a new electron emitter technology which emits electrons with significant kinetic energy and beam current density. 6 figs.

A novel thin-film transistor with step gate-overlapped lightly doped drain and raised source/drain design

NASA Astrophysics Data System (ADS)

Chien, Feng-Tso; Chen, Jian-Liang; Chen, Chien-Ming; Chen, Chii-Wen; Cheng, Ching-Hwa; Chiu, Hsien-Chin

2017-11-01

In this paper, a novel step gate-overlapped lightly doped drain (GOLDD) with raised source/drain (RSD) structure (SGORSD) is proposed for TFT electronic device application. The new SGORSD structure could obtain a low electric field at channel near the drain side owing to a step GOLDD design. Compared to the conventional device, the SGORSD TFT exhibits a better kink effect and higher breakdown performance due to the reduced drain electric field (D-EF). In addition, the leakage current also can be suppressed. Moreover, the device stability, such as the threshold voltage shift and drain current degradation under a high gate bias, is improved by the design of SGORSD structure. Therefore, this novel step GOLDD structure can be a promising design to be used in active-matrix flat panel electronics.

Mobile display technologies: Past developments, present technologies, and future opportunities

NASA Astrophysics Data System (ADS)

Ohshima, Hiroyuki

2014-01-01

It has been thirty years since the first active matrix (AM) flat panel display (FPD) was industrialized for portable televisions (TVs) in 1984. The AM FPD has become a dominant electronic display technology widely used from mobile displays to large TVs. The development of AM FPDs for mobile displays has significantly changed our lives by enabling new applications, such as notebook personal computers (PCs), smartphones and tablet PCs. In the future, the role of mobile displays will become even more important, since mobile displays are the live interface for the world of mobile communications in the era of ubiquitous networks. Various developments are being conducted to improve visual performance, reduce power consumption and add new functionality. At the same time, innovative display concepts and novel manufacturing technologies are being investigated to create new values.

Microgap flat panel display

DOEpatents

Wuest, C.R.

1998-12-08

A microgap flat panel display is disclosed which includes a thin gas-filled display tube that utilizes switched X-Y ``pixel`` strips to trigger electron avalanches and activate a phosphor at a given location on a display screen. The panel utilizes the principal of electron multiplication in a gas subjected to a high electric field to provide sufficient electron current to activate standard luminescent phosphors located on an anode. The X-Y conductive strips of a few micron widths may for example, be deposited on opposite sides of a thin insulating substrate, or on one side of the adjacent substrates and function as a cathode. The X-Y strips are separated from the anode by a gap filled with a suitable gas. Electrical bias is selectively switched onto X and Y strips to activate a ``pixel`` in the region where these strips overlap. A small amount of a long-lived radioisotope is used to initiate an electron avalanche in the overlap region when bias is applied. The avalanche travels through the gas filled gap and activates a luminescent phosphor of a selected color. The bias is adjusted to give a proportional electron multiplication to control brightness for given pixel. 6 figs.

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

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.

Driver-Array Based Flat-Panel Loudspeakers: Theoretical Background and Design Guidelines

NASA Astrophysics Data System (ADS)

Anderson, David Allan

This thesis relates to the simulation and design of flat-panel loudspeakers using moving-coil driver elements. A brief history of the industry is given, including a collection of products and patents from 1925 until the present, an overview of research papers, and a discussion of current products available. The mechanics of bending flat panels are developed with respect to localized driving forces, both in the frequency domain and the time domain as an impulse response. These simulations are compared to measurements on prototype panels. Additional resonant elements influence the behavior of the system: an optional ported rear enclosure and the resonant characteristics of the drivers. The governing equations for these systems are derived and solutions are implemented using equivalent mechanical circuits and numerical methods. The idea of using driver arrays to independently actuate modes of the panel is discussed at length with respect to modal addressability, modal spillover, and experimental validation. The numerical approach to determining the optimal driver placement for a given set of modes is derived and experimentally validated. An investigation of the acoustic behavior of flat panel loudspeakers is presented, using mechanical simulation results to predict the acoustic radiation. The simulations are compared to measurements and found to accurately predict important mechanical and acoustical behaviors. It is demonstrated that a driver array, with the proper biasing, is capable of creating a flat panel loudspeaker which acts more like a piston than a "diffuse radiator" flat panel loudspeaker. The techniques of "Modal Crossover Networks" are introduced, which use multi-band filters to bias the driver array differently for different frequency bands, optimized for audio reproduction. The question of how many drivers are necessary for a modal crossover network is addressed and found to be dependent on the estimated quality factor (Q) of the panel material and edge conditions.

Testing and analysis of flat and curved panels with multiple cracks

NASA Technical Reports Server (NTRS)

Broek, David; Jeong, David Y.; Thomson, Douglas

1994-01-01

An experimental and analytical investigation of multiple cracking in various types of test specimens is described in this paper. The testing phase is comprised of a flat unstiffened panel series and curved stiffened and unstiffened panel series. The test specimens contained various configurations for initial damage. Static loading was applied to these specimens until ultimate failure, while loads and crack propagation were recorded. This data provides the basis for developing and validating methodologies for predicting linkup of multiple cracks, progression to failure, and overall residual strength. The results from twelve flat coupon and ten full scale curved panel tests are presented. In addition, an engineering analysis procedure was developed to predict multiple crack linkup. Reasonable agreement was found between predictions and actual test results for linkup and residual strength for both flat and curved panels. The results indicate that an engineering analysis approach has the potential to quantitatively assess the effect of multiple cracks in the arrest capability of an aircraft fuselage structure.

Direct-reading design charts for 75S-T6 aluminum-alloy flat compression panels having longitudinal extruded Z-section stiffeners

NASA Technical Reports Server (NTRS)

Hickman, William A; Dow, Norris F

1951-01-01

Direct-reading design charts are presented for 75S-T6 aluminum-alloy flat compression panels having longitudinal extruded Z-section stiffeners. These charts, which cover a wide range of proportions, make possible the direct determination of the stress and all panel dimensions required to carry a given intensity of loading with a given skin thickness and effective length of panel.

Investigations of a flat-panel detector for quality assurance measurements in ion beam therapy.

PubMed

Hartmann, Bernadette; Telsemeyer, Julia; Huber, Lucas; Ackermann, Benjamin; Jäkel, Oliver; Martišíková, Mária

2012-01-07

Increased accuracy in radiation delivery to a patient provided by scanning particle beams leads to high demands on quality assurance (QA). To meet the requirements, an extensive quality assurance programme has been implemented at the Heidelberg Ion Beam Therapy Center. Currently, high-resolution radiographic films are used for beam spot position measurements and homogeneity measurements for scanned fields. However, given that using this film type is time and equipment demanding, considerations have been made to replace the radiographic films in QA by another appropriate device. In this study, the suitability of the flat-panel detector RID 256 L based on amorphous silicon was investigated as an alternative method. The currently used radiographic films were taken as a reference. Investigations were carried out for proton and carbon ion beams. The detectors were irradiated simultaneously to allow for a direct comparison. The beam parameters (e.g. energy, focus, position) currently used in the daily QA procedures were applied. Evaluation of the measurements was performed using newly implemented automatic routines. The results for the flat-panel detector were compared to the standard radiographic films. Additionally, a field with intentionally decreased homogeneity was applied to test the detector's sensitivities toward possible incorrect scan parameters. For the beam position analyses, the flat-panel detector results showed good agreement with radiographic films. For both detector types, deviations between measured and planned spot distances were found to be below 1% (1 mm). In homogeneously irradiated fields, the flat-panel detector showed a better dose response homogeneity than the currently used radiographic film. Furthermore, the flat-panel detector is sensitive to field irregularities. The flat-panel detector was found to be an adequate replacement for the radiographic film in QA measurements. In addition, it saves time and equipment because no post-exposure treatment and no developer and darkroom facilities are needed.

Consideration of technologies for head-down displays

NASA Astrophysics Data System (ADS)

Bartlett, Christopher T.

1998-09-01

The market for military avionics head down displays for which Active Matrix Liquid Crystal Displays (AMLCD) has been specified is both well established and substantial. Typical major programs such as F-22, V-22 and Joint Strike Fighter (JSF) amount to over 15,000 displays. Nevertheless there is an insecurity about the situation because of the dependency upon Japanese and Korean manufacturers and the vagaries of the commercial market. The U.S. has only 7% of the world's manufacturing capability in AMLCD and is seeking alternative technologies to regain a hold in this lucrative business. The U.S. military manufacturers of AMLCD are capable, but can never achieve the benefits of scale that Commercial Off The Shelf (COTS) equipment can offer. In addition to the commercial and political concerns, there are still performance issues related to AMLCD and there is a view that emissive displays in particular can offer advantages over AMLCD. However, it is beneficial to be able to tailor display sizes and there are doubts about the ability of current flat panel technologies to achieve custom, or indeed large area panels either economically, or reliably. It is in this arena that projection displays may be the optimum solution.

Comprehensive review on the development of high mobility in oxide thin film transistors

NASA Astrophysics Data System (ADS)

Choi, Jun Young; Lee, Sang Yeol

2017-11-01

Oxide materials are one of the most advanced key technology in the thin film transistors (TFTs) for the high-end of device applications. Amorphous oxide semiconductors (AOSs) have leading technique for flat panel display (FPD), active matrix organic light emitting display (AMOLED) and active matrix liquid crystal display (AMLCD) due to their excellent electrical characteristics, such as field effect mobility ( μ FE ), subthreshold swing (S.S) and threshold voltage ( V th ). Covalent semiconductor like amorphous silicon (a-Si) is attributed to the anti-bonding and bonding states of Si hybridized orbitals. However, AOSs have not grain boundary and excellent performances originated from the unique characteristics of AOS which is the direct orbital overlap between s orbitals of neighboring metal cations. High mobility oxide TFTs have gained attractive attention during the last few years and today in display industries. It is progressively developed to increase the mobility either by exploring various oxide semiconductors or by adopting new TFT structures. Mobility of oxide thin film transistor has been rapidly increased from single digit to higher than 100 cm2/V·s in a decade. In this review, we discuss on the comprehensive review on the mobility of oxide TFTs in a decade and propose bandgap engineering and novel structure to enhance the electrical characteristics of oxide TFTs.

Amorphous Silicon: Flexible Backplane and Display Application

NASA Astrophysics Data System (ADS)

Sarma, Kalluri R.

Advances in the science and technology of hydrogenated amorphous silicon (a-Si:H, also referred to as a-Si) and the associated devices including thin-film transistors (TFT) during the past three decades have had a profound impact on the development and commercialization of major applications such as thin-film solar cells, digital image scanners and X-ray imagers and active matrix liquid crystal displays (AMLCDs). Particularly, during approximately the past 15 years, a-Si TFT-based flat panel AMLCDs have been a huge commercial success. a-Si TFT-LCD has enabled the note book PCs, and is now rapidly replacing the venerable CRT in the desktop monitor and home TV applications. a-Si TFT-LCD is now the dominant technology in use for applications ranging from small displays such as in mobile phones to large displays such as in home TV, as well-specialized applications such as industrial and avionics displays.

Clinical comparative study with a large-area amorphous silicon flat-panel detector: image quality and visibility of anatomic structures on chest radiography.

PubMed

Fink, Christian; Hallscheidt, Peter J; Noeldge, Gerd; Kampschulte, Annette; Radeleff, Boris; Hosch, Waldemar P; Kauffmann, Günter W; Hansmann, Jochen

2002-02-01

The objective of this study was to compare clinical chest radiographs of a large-area, flat-panel digital radiography system and a conventional film-screen radiography system. The comparison was based on an observer preference study of image quality and visibility of anatomic structures. Routine follow-up chest radiographs were obtained from 100 consecutive oncology patients using a large-area, amorphous silicon flat-panel detector digital radiography system (dose equivalent to a 400-speed film system). Hard-copy images were compared with previous examinations of the same individuals taken on a conventional film-screen system (200-speed). Patients were excluded if changes in the chest anatomy were detected or if the time interval between the examinations exceeded 1 year. Observer preference was evaluated for the image quality and the visibility of 15 anatomic structures using a five-point scale. Dose measurements with a chest phantom showed a dose reduction of approximately 50% with the digital radiography system compared with the film-screen radiography system. The image quality and the visibility of all but one anatomic structure of the images obtained with the digital flat-panel detector system were rated significantly superior (p < or = 0.0003) to those obtained with the conventional film-screen radiography system. The image quality and visibility of anatomic structures on the images obtained by the flat-panel detector system were perceived as equal or superior to the images from conventional film-screen chest radiography. This was true even though the radiation dose was reduced approximately 50% with the digital flat-panel detector system.

Performance comparison of flat static and adjustable angle solar panels for sunny weather

NASA Astrophysics Data System (ADS)

Chua, Yaw Long; Yong, Yoon Kuang

2017-04-01

Nowadays solar panels are commonly used to collect sunlight so that it could convert solar energy into electrical energy. The power generated by the solar panels depends on the amount of sunlight collected on the solar panels. This paper presents a study that was carried out to study how changing the angle of the solar panels will impact the amount of electrical energy collected after conversion and the efficiencies of the solar panels. In this paper, the solar panels were placed at 30°, 35° and 40° angles throughout different days. The energy collected is then compared with energy collected by a flat static solar panel. It turns out that the solar panels with 40° angle performed best among the other angle solar panels.

Some sound transmission loss characteristics of typical general aviation structural materials

NASA Technical Reports Server (NTRS)

Roskam, J.; Van Dam, C.; Grosveld, F.; Durenberger, D.

1978-01-01

Experimentally measured sound transmission loss characteristics of flat aluminum panels with and without damping and stiffness treatment are presented and discussed. The effect of pressurization on sound transmission loss of flat aluminum panels is shown to be significant.

Color quality management in advanced flat panel display engines

NASA Astrophysics Data System (ADS)

Lebowsky, Fritz; Neugebauer, Charles F.; Marnatti, David M.

2003-01-01

During recent years color reproduction systems for consumer needs have experienced various difficulties. In particular, flat panels and printers could not reach a satisfactory color match. The RGB image stored on an Internet server of a retailer did not show the desired colors on a consumer display device or printer device. STMicroelectronics addresses this important color reproduction issue inside their advanced display engines using novel algorithms targeted for low cost consumer flat panels. Using a new and genuine RGB color space transformation, which combines a gamma correction Look-Up-Table, tetrahedrization, and linear interpolation, we satisfy market demands.

Alternatives to flat panel displays in vehicle turrets

NASA Astrophysics Data System (ADS)

Nicholson, Gail

2011-06-01

Space is a premium in vehicle turrets. Reducing the footprint of displays inside turrets frees up space for the warfighter. Traditional military ruggedized flat panel displays cannot reside flush with the curved turret wall and consumes more space than their advertized size. The lack of turret space also makes balancing human factors difficult. To better meet the Warfighter needs, alternatives and incremental upgrades to the flat panel displays in turrets were compiled. Each alternative technology was assessed against the constraints of a turret. Benefits, issues, and predictions to implementation are summarized. Viable alternatives are being developed into suitable options.

Optimization of reading conditions for flat panel displays.

PubMed

Thomas, J A; Chakrabarti, K; Kaczmarek, R V; Maslennikov, A; Mitchell, C A; Romanyukha, A

2006-06-01

Task Group 18 (TG 18) of the American Association of Physicists in Medicine has developed guidelines for Assessment of Display Performance for Medical Imaging Systems. In this document, a method for determination of the maximum room lighting for displays is suggested. It is based on luminance measurements of a black target displayed on each display device at different room illuminance levels. Linear extrapolation of the above luminance measurements vs. room illuminance allows one to determine diffuse and specular reflection coefficients. TG 18 guidelines have established recommended maximum room lighting. It is based on the characterization of the display by its minimum and maximum luminance and the description of room by diffuse and specular coefficients. We carried out these luminance measurements for three selected displays to determine their optimum viewing conditions: one cathode ray tube and two flat panels. We found some problems with the application of the TG 18 guidelines to optimize viewing conditions for IBM T221 flat panels. Introduction of the requirement for minimum room illuminance allows a more accurate determination of the optimal viewing conditions (maximum and minimum room illuminance) for IBM flat panels. It also addresses the possible loss of contrast in medical images on flat panel displays because of the effect of nonlinearity in the dependence of luminance on room illuminance at low room lighting.

Technical advances of interventional fluoroscopy and flat panel image receptor.

PubMed

Lin, Pei-Jan Paul

2008-11-01

In the past decade, various radiation reducing devices and control circuits have been implemented on fluoroscopic imaging equipment. Because of the potential for lengthy fluoroscopic procedures in interventional cardiovascular angiography, these devices and control circuits have been developed for the cardiac catheterization laboratories and interventional angiography suites. Additionally, fluoroscopic systems equipped with image intensifiers have benefited from technological advances in x-ray tube, x-ray generator, and spectral shaping filter technologies. The high heat capacity x-ray tube, the medium frequency inverter generator with high performance switching capability, and the patient dose reduction spectral shaping filter had already been implemented on the image intensified fluoroscopy systems. These three underlying technologies together with the automatic dose rate and image quality (ADRIQ) control logic allow patients undergoing cardiovascular angiography procedures to benefit from "lower patient dose" with "high image quality." While photoconductor (or phosphor plate) x-ray detectors and signal capture thin film transistor (TFT) and charge coupled device (CCD) arrays are analog in nature, the advent of the flat panel image receptor allowed for fluoroscopy procedures to become more streamlined. With the analog-to-digital converter built into the data lines, the flat panel image receptor appears to become a digital device. While the transition from image intensified fluoroscopy systems to flat panel image receptor fluoroscopy systems is part of the on-going "digitization of imaging," the value of a flat panel image receptor may have to be evaluated with respect to patient dose, image quality, and clinical application capabilities. The advantage of flat panel image receptors has yet to be fully explored. For instance, the flat panel image receptor has its disadvantages as compared to the image intensifiers; the cost of the equipment is probably the most obvious. On the other hand, due to its wide dynamic range and linearity, lowering of patient dose beyond current practice could be achieved through the calibration process of the flat panel input dose rate being set to, for example, one half or less of current values. In this article various radiation saving devices and control circuits are briefly described. This includes various types of fluoroscopic systems designed to strive for reduction of patient exposure with the application of spectral shaping filters. The main thrust is to understand the ADRIQ control logic, through equipment testing, as it relates to clinical applications, and to show how this ADRIQ control logic "ties" those three technological advancements together to provide low radiation dose to the patient with high quality fluoroscopic images. Finally, rotational angiography with computed tomography (CT) and three dimensional (3-D) images utilizing flat panel technology will be reviewed as they pertain to diagnostic imaging in cardiovascular disease.

Voltage Drop Compensation Method for Active Matrix Organic Light Emitting Diode Displays

NASA Astrophysics Data System (ADS)

Choi, Sang-moo; Ryu, Do-hyung; Kim, Keum-nam; Choi, Jae-beom; Kim, Byung-hee; Berkeley, Brian

2011-03-01

In this paper, the conventional voltage drop compensation methods are reviewed and the novel design and driving scheme, the advanced power de-coupled (aPDC) driving method, is proposed to effectively compensate the voltage IR drop of active matrix light emitting diode (AMOLED) displays. The advanced PDC driving scheme can be applied to general AMOLED pixel circuits that have been developed with only minor modification or without requiring modification in pixel circuit. A 14-in. AMOLED panel with the aPDC driving scheme was fabricated. Long range uniformity (LRU) of the 14-in. AMOLED panel was improved from 43% without the aPDC driving scheme, to over 87% at the same brightness by using the scheme and the layout complexity of the panel with new design scheme is less than that of the panel with the conventional design scheme.

Buckling coefficients for simply supported and camped flat, rectangular sandwich panels under edgewise compression

Treesearch

Edward W. Kuenzi; Charles B. Norris; Paul M. Jenkinson

1964-01-01

“This report presents curves of coefficients and formulas for use in calculating the buckling of flat panels of sandwich construction under edgewise compressive loads. The curves were derived for sandwich panels having one facing of either of two orthotropic materials, the other facing of an isotropic material; both facings of orthotropic material; both facings of...

Requirements for AMLCDs in U.S. military applications

NASA Astrophysics Data System (ADS)

Hopper, Darrel G.; Desjardins, Daniel D.

1995-06-01

Flat panel displays are fast becoming a significant source of more defense for less money. Military instruments have begun to use color active matrix liquid crystal displays (AMLCDs). This is the beginning of a significant transition from electromechanical, CRT. dichroic LCD, and electroluminescent display designs to the AMLCD designs. We have the opportunity with this new technology to establish common products capable of meeting user requirements for sunlight-readable, color and grayscale capable, high-sharpness high-pixel count, flat panel displays for military applications. The Wright Laboratory is leading the development of recommended best practice, draft guidance standard, and performance specifications for this new generation, the flat panel cockpit display generation, of display modules based on requirements for U.S. military aircraft and ground combat human system interfaces. These requirements are similar in many regards to those in both the civil aviation and automotive industries; accordingly, commonality with these civil applications is incorporated where possible, against the requirements for military combat applications. The performance requirement may be achieved by two approaches: militarization of displays made to low requirements of a large volume civil products manufacturer like Sharp or integration of displays made to high requirements by a niche market commercial vendor, like Optical Imaging Systems, Litton Systems Limited, ImageQuest Inc., and Planar Advanced Inc. teamed with Xerox PARC and Standish Industries. [Note that the niche market companies listed are commercial off-the shelf vendors, albeit for high requirement low volume customers.] Given that the performance specifications can be met for a particular military product by either approach, the choice is based on life cycle cost and a thin analysis based on initial costs alone is not acceptable as it ignores the fact that military product life cycles and procurements are 20-60 years compared to 1.5 years for civil products. Thus far there is no convincing evidence that the large volume commercial product approach for combat systems will meet the combat performance specification or be cheaper from a life cycle cost perspective. National and economic security requirements require some military/avionic-grade AMLCD production domestically (i.e. in the U.S. and/or Canada). Examples of AMLCD demand and performance requirements in U.S. military systems are provided.

Fabrication And Evaluation Of Sic/Sic Tubes With Various Fiber Architectures

NASA Technical Reports Server (NTRS)

Yun, H. M.; DiCarlo, J. A.; Fox, D. S.

2003-01-01

SiC/SiC composites are excellent material candidates for high temperature applications where the performance requirements are high strength, high creep-rupture resistance, high environmental durability, and high thermal conductivity. In the past, the NASA UEET program has demonstrated fabrication of high-performance SiC/SiC flat panels reinforced by Sylramic-iBN SiC fibers. Currently NASA UEET is scaling up this SiC/SiC system by fabrication of more complex shaped components using the same fiber type. This paper reports the effects of various fiber architectures on the processing, mechanical, and durability behavior of small-diameter 0.5" ID SiC/SiC tubes, which are potential sub-elements for leading edges and cooling channels in turbine vanes and blades. Nine different fiber architectures were utilized for construction of seamless tube preforms, from simple 2D jelly-rolling to complex braiding, pin-weaving, filament-winding and 3D orthogonal weaving with approximately 5% fibers in the thru-thickness direction. Using the BN interphase and Sic matrix processing steps established for the flat panels, SiC/SiC tubes were fabricated with wall thicknesses of approximately 60 mils and total fiber fractions of approximately 35%. The "D" split ring tests for hoop tensile properties, micro-structural examinations for relationship between fiber architecture formation and matrix infiltration, and the low-pressure burner rig tests for the high temperature durability under thru-thickness thermal gradient were conducted. The better matrix infiltration and higher hoop strength were achieved using the tri-axial braided and the three-float pin woven SiC/SiC tubes. In general, it needs not only higher hoop direction fibers but also axial direction fibers for the higher hoop strength and the better infiltration, respectively. These results are analyzed to offer general guidelines for selecting fiber pre-form architectures and SiC/SiC processes that maximize tube hoop strength, thru-thickness thermal conductivity, and burner-rig durability under a high thermal gradient.

Flat-panel cone-beam CT: a novel imaging technology for image-guided procedures

NASA Astrophysics Data System (ADS)

Siewerdsen, Jeffrey H.; Jaffray, David A.; Edmundson, Gregory K.; Sanders, W. P.; Wong, John W.; Martinez, Alvaro A.

2001-05-01

The use of flat-panel imagers for cone-beam CT signals the emergence of an attractive technology for volumetric imaging. Recent investigations demonstrate volume images with high spatial resolution and soft-tissue visibility and point to a number of logistical characteristics (e.g., open geometry, volume acquisition in a single rotation about the patient, and separation of the imaging and patient support structures) that are attractive to a broad spectrum of applications. Considering application to image-guided (IG) procedures - specifically IG therapies - this paper examines the performance of flat-panel cone-beam CT in relation to numerous constraints and requirements, including time (i.e., speed of image acquisition), dose, and field-of-view. The imaging and guidance performance of a prototype flat panel cone-beam CT system is investigated through the construction of procedure-specific tasks that test the influence of image artifacts (e.g., x-ray scatter and beam-hardening) and volumetric imaging performance (e.g., 3D spatial resolution, noise, and contrast) - taking two specific examples in IG brachytherapy and IG vertebroplasty. For IG brachytherapy, a procedure-specific task is constructed which tests the performance of flat-panel cone-beam CT in measuring the volumetric distribution of Pd-103 permanent implant seeds in relation to neighboring bone and soft-tissue structures in a pelvis phantom. For IG interventional procedures, a procedure-specific task is constructed in the context of vertebroplasty performed on a cadaverized ovine spine, demonstrating the volumetric image quality in pre-, intra-, and post-therapeutic images of the region of interest and testing the performance of the system in measuring the volumetric distribution of bone cement (PMMA) relative to surrounding spinal anatomy. Each of these tasks highlights numerous promising and challenging aspects of flat-panel cone-beam CT applied to IG procedures.

Comparison of hand laid-up tape and filament wound composite cylinders and panels with and without impact damage

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.; Lopez, Osvaldo F.

1991-01-01

Experimentally determined axial compressive failure loads, strains and failure modes of composite flat panels and cylinders are presented. A comparison of two types of filament wound flat graphite-epoxy panels indicates that the winding pattern can influence structural response. A comparison of hand laid-up tape and filament wound composite cylinders indicates that fabrication method may not significantly influence the failure mode or average failure strain of thick-walled (radius-to-thickness ratio less than 15) graphite-epoxy cylinders. The interaction of manufacturing-induced features (fiber cross-overs) and low-speed impact damage for graphite-epoxy specimens is also presented. Filament would flat panels with many fiber cross-overs exhibited lower failure strains than filament wound panels without fiber cross-overs for all impact speeds examined. Graphite-thermoplastic cylinders exhibited a significantly different failure mode from the graphite-epoxy cylinders.

High-performance flat-panel solar thermoelectric generators with high thermal concentration

NASA Astrophysics Data System (ADS)

Kraemer, Daniel; Poudel, Bed; Feng, Hsien-Ping; Caylor, J. Christopher; Yu, Bo; Yan, Xiao; Ma, Yi; Wang, Xiaowei; Wang, Dezhi; Muto, Andrew; McEnaney, Kenneth; Chiesa, Matteo; Ren, Zhifeng; Chen, Gang

2011-07-01

The conversion of sunlight into electricity has been dominated by photovoltaic and solar thermal power generation. Photovoltaic cells are deployed widely, mostly as flat panels, whereas solar thermal electricity generation relying on optical concentrators and mechanical heat engines is only seen in large-scale power plants. Here we demonstrate a promising flat-panel solar thermal to electric power conversion technology based on the Seebeck effect and high thermal concentration, thus enabling wider applications. The developed solar thermoelectric generators (STEGs) achieved a peak efficiency of 4.6% under AM1.5G (1 kW m-2) conditions. The efficiency is 7-8 times higher than the previously reported best value for a flat-panel STEG, and is enabled by the use of high-performance nanostructured thermoelectric materials and spectrally-selective solar absorbers in an innovative design that exploits high thermal concentration in an evacuated environment. Our work opens up a promising new approach which has the potential to achieve cost-effective conversion of solar energy into electricity.

The x-ray light valve: a low-cost, digital radiographic imaging system-spatial resolution

NASA Astrophysics Data System (ADS)

MacDougall, Robert D.; Koprinarov, Ivaylo; Webster, Christie A.; Rowlands, J. A.

2007-03-01

In recent years, new x-ray radiographic systems based on large area flat panel technology have revolutionized our capability to produce digital x-ray radiographic images. However, these active matrix flat panel imagers (AMFPIs) are extraordinarily expensive compared to the systems they are replacing. Thus there is a need for a low cost digital imaging system for general applications in radiology. Different approaches have been considered to make lower cost, integrated x-ray imaging devices for digital radiography, including: scanned projection x-ray, an integrated approach based on computed radiography technology and optically demagnified x-ray screen/CCD systems. These approaches suffer from either high cost or high mechanical complexity and do not have the image quality of AMFPIs. We have identified a new approach - the X-ray Light Valve (XLV). The XLV has the potential to achieve the immediate readout in an integrated system with image quality comparable to AMFPIs. The XLV concept combines three well-established and hence lowcost technologies: an amorphous selenium (a-Se) layer to convert x-rays to image charge, a liquid crystal (LC) cell as an analog display, and an optical scanner for image digitization. Here we investigate the spatial resolution possible with XLV systems. Both a-Se and LC cells have both been shown separately to have inherently very high spatial resolution. Due to the close electrostatic coupling in the XLV, it can be expected that the spatial resolution of this system will also be very high. A prototype XLV was made and a typical office scanner was used for image digitization. The Modulation Transfer Function was measured and the limiting factor was seen to be the optical scanner. However, even with this limitation the XLV system is able to meet or exceed the resolution requirements for chest radiography.

Experimental flat-panel high-spatial-resolution volume CT of the temporal bone.

PubMed

Gupta, Rajiv; Bartling, Soenke H; Basu, Samit K; Ross, William R; Becker, Hartmut; Pfoh, Armin; Brady, Thomas; Curtin, Hugh D

2004-09-01

A CT scanner employing a digital flat-panel detector is capable of very high spatial resolution as compared with a multi-section CT (MSCT) scanner. Our purpose was to determine how well a prototypical volume CT (VCT) scanner with a flat-panel detector system defines fine structures in temporal bone. Four partially manipulated temporal-bone specimens were imaged by use of a prototypical cone-beam VCT scanner with a flat-panel detector system at an isometric resolution of 150 microm at the isocenter. These specimens were also depicted by state-of-the-art multisection CT (MSCT). Forty-two structures imaged by both scanners were qualitatively assessed and rated, and scores assigned to VCT findings were compared with those of MSCT. Qualitative assessment of anatomic structures, lesions, cochlear implants, and middle-ear hearing aids indicated that image quality was significantly better with VCT (P < .001). Structures near the spatial-resolution limit of MSCT (e.g., bony covering of the tympanic segment of the facial canal, the incudo-stapedial joint, the proximal vestibular aqueduct, the interscalar septum, and the modiolus) had higher contrast and less partial-volume effect with VCT. The flat-panel prototype provides better definition of fine osseous structures of temporal bone than that of currently available MSCT scanners. This study provides impetus for further research in increasing spatial resolution beyond that offered by the current state-of-the-art scanners.

Experimental Approach on the Behavior of Composite Laminated Shell under Transverse Impact Loading

NASA Astrophysics Data System (ADS)

Kim, Y. N.; Im, K. H.; Lee, K. S.; Cho, Y. J.; Kim, S. H.; Yang, I. Y.

2005-04-01

Composites are to be considered for many structural applications structural weight. These materials have high strength-to-weight and stiffness-to-weight ratios. However, they are susceptible to impact loading because they are laminar systems with weak interfaces. Matrix cracking and delamination are the most common damage mechanisms of low velocity impact and are dependent on each other. This paper is to study the behavior of composite shell under transverse impact loading. In this study, carbon-epoxy composite laminates with various curvatures was used. Low velocity impact tests were performed using a drop weight testing machine. The 100mm×100mm shells were clamped in order to produce a central circular area (φ=80mm). An hemispherical impactor (m=0.1kg and φ=10mm) was used and the tests were done with velocities ranging from 2.8 to 4.8 m/s. The real curve force/time was registered in order to obtain the maximum contact force and contact time. And then, we know that contact force and delamination area of flat-plate is higher than cylindrical shell panel in the same kinetic energy level, and flat-plate is easily penetrated than cylindrical shell panel. And contact force, deflection and delamination area decrease as the curvature increase.

Musculoskeletal imaging with a prototype photon-counting detector.

PubMed

Gruber, M; Homolka, P; Chmeissani, M; Uffmann, M; Pretterklieber, M; Kainberger, F

2012-01-01

To test a digital imaging X-ray device based on the direct capture of X-ray photons with pixel detectors, which are coupled with photon-counting readout electronics. The chip consists of a matrix of 256 × 256 pixels with a pixel pitch of 55 μm. A monolithic image of 11.2 cm × 7 cm was obtained by the consecutive displacement approach. Images of embalmed anatomical specimens of eight human hands were obtained at four different dose levels (skin dose 2.4, 6, 12, 25 μGy) with the new detector, as well as with a flat-panel detector. The overall rating scores for the evaluated anatomical regions ranged from 5.23 at the lowest dose level, 6.32 at approximately 6 μGy, 6.70 at 12 μGy, to 6.99 at the highest dose level with the photon-counting system. The corresponding rating scores for the flat-panel detector were 3.84, 5.39, 6.64, and 7.34. When images obtained at the same dose were compared, the new system outperformed the conventional DR system at the two lowest dose levels. At the higher dose levels, there were no significant differences between the two systems. The photon-counting detector has great potential to obtain musculoskeletal images of excellent quality at very low dose levels.

Toward Scintillator High-Gain Avalanche Rushing Photoconductor Active Matrix Flat Panel Imager (SHARP-AMFPI): Initial fabrication and characterization.

PubMed

Scheuermann, James R; Howansky, Adrian; Hansroul, Marc; Léveillé, Sébastien; Tanioka, Kenkichi; Zhao, Wei

2018-02-01

We present the first prototype Scintillator High-Gain Avalanche Rushing Photoconductor Active Matrix Flat Panel Imager (SHARP-AMFPI). This detector includes a layer of avalanche amorphous Selenium (a-Se) (HARP) as the photoconductor in an indirect detector to amplify the signal and reduce the effects of electronic noise to obtain quantum noise-limited images for low-dose applications. It is the first time avalanche a-Se has been used in a solid-state imaging device and poses as a possible solution to eliminate the effects of electronic noise, which is crucial for low-dose imaging performance of AMFPI. We successfully deposited a solid-state HARP structure onto a 24 × 30 cm 2 array of thin-film transistors (TFT array) with a pixel pitch of 85 μm. The HARP layer consists of 16 μm of a-Se with a hole-blocking and electron-blocking layer to prevent charge injection from the high-voltage bias and pixel electrodes, respectively. An electric field (E S e ) up to 105 V μm -1 was applied across the a-Se layer without breakdown. A 150 μm thick-structured CsI:Tl scintillator was used to form SHARP-AMFPI. The x-ray imaging performance is characterized using a 30 kVp Mo/Mo beam. We evaluate the spatial resolution, noise power, and detective quantum efficiency at zero frequency of the system with and without avalanche gain. The results are analyzed using cascaded linear system model (CLSM). An avalanche gain of 76 ± 5 was measured at E S e = 105 V μm -1 . We demonstrate that avalanche gain can amplify the signal to overcome electronic noise. As avalanche gain is increased, image quality improves for a constant (0.76 mR) exposure until electronic noise is overcome. Our system is currently limited by poor optical transparency of our high-voltage electrode and long integrating time which results in dark current noise. These two effects cause high-spatial frequency noise to dominate imaging performance. We demonstrate the feasibility of a solid-state HARP x-ray imager and have fabricated the largest active area HARP sensor to date. Procedures to reduce secondary quantum and dark noise are outlined. Future work will improve optical coupling and charge transport which will allow for frequency DQE and temporal metrics to be obtained. © 2017 American Association of Physicists in Medicine.

75 FR 42783 - Notice of Receipt of Complaint; Solicitation of Comments Relating to the Public Interest

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-22

... Re Certain Flat Panel Digital Televisions and Components Thereof''; the Commission is soliciting... importation of certain flat panel digital televisions and components thereof. The complaint names as..., competitive conditions in the United States economy, the production of like or directly competitive articles...

76 FR 4578 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Adoption of Control...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-26

... Wood Paneling Coatings AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule. SUMMARY... (RACT) for sources covered by EPA's Control Techniques Guidelines (CTG) for flat wood paneling coatings. These amendments will reduce emissions of volatile organic compound (VOC) from flat wood coating...

Repair techniques for celion/LARC-160 graphite/polyimide composite structures

NASA Technical Reports Server (NTRS)

Jones, J. S.; Graves, S. R.

1984-01-01

The large stiffness-to-weight and strength-to-weight ratios of graphite composite in combination with the 600 F structural capability of the polyimide matrix can reduce the total structure/TPS weight of reusable space vehicles by 20-30 percent. It is inevitable that with planned usage of GR/PI structural components, damage will occur either in the form of intrinsic flaw growth or mechanical damage. Research and development programs were initiated to develop repair processes and techniques specific to Celion/LARC-160 GR/PI structure with emphasis on highly loaded and lightly loaded compression critical structures for factory type repair. Repair processes include cocure and secondary bonding techniques applied under vacuum plus positive autoclave pressure. Viable repair designs and processes are discussed for flat laminates, honeycomb sandwich panels, and hat-stiffened skin-stringer panels. The repair methodology was verified through structural element compression tests at room temperature and 315 C (600 F).

Supersonic Panel Flutter Test Results for Flat Fiber-Glass Sandwich Panels with Foamed Cores

NASA Technical Reports Server (NTRS)

Tuovila, W. J.; Presnell, John G., Jr.

1961-01-01

Flutter tests have been made on flat panels having a 1/4 inch-thick plastic-foam core covered with thin fiber-glass laminates. The testing was done in the Langley Unitary Plan wind tunnel at Mach numbers from 1.76 t o 2.87. The flutter boundary for these panels was found to be near the flutter boundary of thin metal panels when compared on the basis of an equivalent panel stiffness. The results also demonstrated that the depth of the cavity behind the panel has a pronounced influence on flutter. Changing the cavity depth from 1 1/2 inches to 1/2 inch reduced the dynamic pressure at start of flutter by 40 percent. No flutter was obtained when the spacers on the back of the panel were against the bottom of the cavity.

Recommendations for the performance rating of flat plate terrestrial photovoltaic solar panels

NASA Technical Reports Server (NTRS)

Treble, F. C.

1976-01-01

A review of recommendations for standardizing the performance rating of flat plate terrestrial solar panels is given to develop an international standard code of practice for performance rating. Required data to characterize the performance of a solar panel are listed. Other items discussed are: (1) basic measurement procedures; (2) performance measurement in natural sunlight and simulated sunlight; (3) standard solar cells; (4) the normal incidence method; (5) global method and (6) definition of peak power.

Colorimetric characterization models based on colorimetric characteristics evaluation for active matrix organic light emitting diode panels.

PubMed

Gong, Rui; Xu, Haisong; Tong, Qingfen

2012-10-20

The colorimetric characterization of active matrix organic light emitting diode (AMOLED) panels suffers from their poor channel independence. Based on the colorimetric characteristics evaluation of channel independence and chromaticity constancy, an accurate colorimetric characterization method, namely, the polynomial compensation model (PC model) considering channel interactions was proposed for AMOLED panels. In this model, polynomial expressions are employed to calculate the relationship between the prediction errors of XYZ tristimulus values and the digital inputs to compensate the XYZ prediction errors of the conventional piecewise linear interpolation assuming the variable chromaticity coordinates (PLVC) model. The experimental results indicated that the proposed PC model outperformed other typical characterization models for the two tested AMOLED smart-phone displays and for the professional liquid crystal display monitor as well.

Flat panel display test and evaluation: procedures, standards, and facilities

NASA Astrophysics Data System (ADS)

Jackson, Timothy W.; Daniels, Reginald; Hopper, Darrel G.

1997-07-01

This paper addresses flat panel display test and evaluation via a discussion of procedures, standards and facilities. Procedures need to be carefully developed and documented to ensure that test accomplished in separate laboratories produce comparable results. The tests themselves must not be a source of inconsistency in test results when such comparisons are made in the course of procurements or new technology prototype evaluations. Standards are necessary to expedite the transition of the new display technologies into applications and to lower the costs of custom parts applied across disparate applications. The flat panel display industry is in the course of ascertaining and formulating such standards as they are of value to designers, manufacturers, marketers and users of civil and military products and equipment. Additionally, in order to inform the DoD and industry, the test and evaluation facilities of the Air Force Research Laboratory Displays Branch are described. These facilities are available to support procurements involving flat panel displays and to examine new technology prototypes. Finally, other government display testing facilities within the Navy and the Army are described.

High-performance flat-panel solar thermoelectric generators with high thermal concentration.

PubMed

Kraemer, Daniel; Poudel, Bed; Feng, Hsien-Ping; Caylor, J Christopher; Yu, Bo; Yan, Xiao; Ma, Yi; Wang, Xiaowei; Wang, Dezhi; Muto, Andrew; McEnaney, Kenneth; Chiesa, Matteo; Ren, Zhifeng; Chen, Gang

2011-05-01

The conversion of sunlight into electricity has been dominated by photovoltaic and solar thermal power generation. Photovoltaic cells are deployed widely, mostly as flat panels, whereas solar thermal electricity generation relying on optical concentrators and mechanical heat engines is only seen in large-scale power plants. Here we demonstrate a promising flat-panel solar thermal to electric power conversion technology based on the Seebeck effect and high thermal concentration, thus enabling wider applications. The developed solar thermoelectric generators (STEGs) achieved a peak efficiency of 4.6% under AM1.5G (1 kW m(-2)) conditions. The efficiency is 7-8 times higher than the previously reported best value for a flat-panel STEG, and is enabled by the use of high-performance nanostructured thermoelectric materials and spectrally-selective solar absorbers in an innovative design that exploits high thermal concentration in an evacuated environment. Our work opens up a promising new approach which has the potential to achieve cost-effective conversion of solar energy into electricity. © 2011 Macmillan Publishers Limited. All rights reserved

Effect of Boundary Conditions on the Back Face Deformations of Flat UHMWPE Panels

DTIC Science & Technology

2014-12-01

Zhang [2] carried out a numerical study of the effects of clamping type and clamping pressure on the ballistic performance of woven Kevlar , and found...effects of composite size were also studied. Singletary [5] studied the effects of boundary conditions and panel sizes on V50 for Kevlar KM2 fabric. The...on the BFD in flat UHMWPE panels. UHMWPE possesses high tenacity and high strength compared to Kevlar , as a result of which it is the material of

TOPICAL REVIEW: Electronic portal imaging devices: a review and historical perspective of contemporary technologies and research

NASA Astrophysics Data System (ADS)

Antonuk, Larry E.

2002-03-01

A review of electronic portal imaging devices (EPIDs) used in external beam, megavoltage radiation therapy is presented. The review consists of a brief introduction to the definition, role and clinical significance of portal imaging, along with a discussion of radiotherapy film systems and the motivations for EPIDs. This is followed by a summary of the challenges and constraints inherent to portal imaging along with a concise, historical review of the technologies that have been explored and developed. The paper then examines, in greater depth, the two first-generation technologies that have found widespread clinical use starting from the late 1980s. This is followed by a broad overview of the physics, operation, properties and advantages of active matrix, flat-panel, megavoltage imagers, presently being commercially introduced to clinical environments or expected to be introduced in the future. Finally, a survey of contemporary research efforts focused on improving portal imaging performance by addressing various weaknesses in existing commercial systems is presented.

Configuration and Sizing of a Test Fixture for Panels Under Combined Loads

NASA Technical Reports Server (NTRS)

Lovejoy, Andrew E.

2006-01-01

Future air and space structures are expected to utilize composite panels that are subjected to combined mechanical loads, such as bi-axial compression/tension, shear and pressure. Therefore, the ability to accurately predict the buckling and strength failures of such panels is important. While computational analysis can provide tremendous insight into panel response, experimental results are necessary to verify predicted performances of these panels to judge the accuracy of computational methods. However, application of combined loads is an extremely difficult task due to the complex test fixtures and set-up required. Presented herein is a comparison of several test set-ups capable of testing panels under combined loads. Configurations compared include a D-box, a segmented cylinder and a single panel set-up. The study primarily focuses on the preliminary sizing of a single panel test configuration capable of testing flat panels under combined in-plane mechanical loads. This single panel set-up appears to be best suited to the testing of both strength critical and buckling critical panels. Required actuator loads and strokes are provided for various square, flat panels.

Determination of washout performance of various monochrome displays under simulated flight ambient and solar lighting conditions

NASA Technical Reports Server (NTRS)

Batson, Vernon M.; Robertson, James B.; Parrish, Russell V.

1990-01-01

The aircraft cockpit ambient lighting simulation system (ACALSS) has been developed to study display readability and associated pilot/vehicle performance effects in a part-task simulator cockpit. In the study reported here, the ACALSS was used to determine the illumination levels at which subjects lose the ability to maintain aircraft states when using three display technologies as display media for primary flight displays: a standard monochrome EL (electroluminescent) flat-panel, a laboratory-class monochrome CRT, and an enhanced-brightness EL flat-panel. The multivariate statistical technique of modified profile analysis was used to test for performance differences between display devices as functions of illumination levels. The standard monochrome EL flat-panel display began to washout after the 2500 foot-candle level of illumination. The monochrome CRT began to washout after the 5500 foot-candle level of illumination. No performance decrements by increased illumination up to the 12,000 foot-candle level were found for the enhanced-brightness EL flat-panel display. What was not anticipated was that half the subjects would subjectively prefer the CRT over the enhanced-brightness EL, even though their performance errors would have indicated the opposite.

A generalized reconstruction framework for unconventional PET systems

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

Mathews, Aswin John, E-mail: amathews@wustl.edu; Li, Ke; O’Sullivan, Joseph A.

2015-08-15

Purpose: Quantitative estimation of the radionuclide activity concentration in positron emission tomography (PET) requires precise modeling of PET physics. The authors are focused on designing unconventional PET geometries for specific applications. This work reports the creation of a generalized reconstruction framework, capable of reconstructing tomographic PET data for systems that use right cuboidal detector elements positioned at arbitrary geometry using a regular Cartesian grid of image voxels. Methods: The authors report on a variety of design choices and optimization for the creation of the generalized framework. The image reconstruction algorithm is maximum likelihood-expectation–maximization. System geometry can be specified using amore » simple script. Given the geometry, a symmetry seeking algorithm finds existing symmetry in the geometry with respect to the image grid to improve the memory usage/speed. Normalization is approached from a geometry independent perspective. The system matrix is computed using the Siddon’s algorithm and subcrystal approach. The program is parallelized through open multiprocessing and message passing interface libraries. A wide variety of systems can be modeled using the framework. This is made possible by modeling the underlying physics and data correction, while generalizing the geometry dependent features. Results: Application of the framework for three novel PET systems, each designed for a specific application, is presented to demonstrate the robustness of the framework in modeling PET systems of unconventional geometry. Three PET systems of unconventional geometry are studied. (1) Virtual-pinhole half-ring insert integrated into Biograph-40: although the insert device improves image quality over conventional whole-body scanner, the image quality varies depending on the position of the insert and the object. (2) Virtual-pinhole flat-panel insert integrated into Biograph-40: preliminary results from an investigation into a modular flat-panel insert are presented. (3) Plant PET system: a reconfigurable PET system for imaging plants, with resolution of greater than 3.3 mm, is shown. Using the automated symmetry seeking algorithm, the authors achieved a compression ratio of the storage and memory requirement by a factor of approximately 50 for the half-ring and flat-panel systems. For plant PET system, the compression ratio is approximately five. The ratio depends on the level of symmetry that exists in different geometries. Conclusions: This work brings the field closer to arbitrary geometry reconstruction. A generalized reconstruction framework can be used to validate multiple hypotheses and the effort required to investigate each system is reduced. Memory usage/speed can be improved with certain optimizations.« less

A generalized reconstruction framework for unconventional PET systems.

PubMed

Mathews, Aswin John; Li, Ke; Komarov, Sergey; Wang, Qiang; Ravindranath, Bosky; O'Sullivan, Joseph A; Tai, Yuan-Chuan

2015-08-01

Quantitative estimation of the radionuclide activity concentration in positron emission tomography (PET) requires precise modeling of PET physics. The authors are focused on designing unconventional PET geometries for specific applications. This work reports the creation of a generalized reconstruction framework, capable of reconstructing tomographic PET data for systems that use right cuboidal detector elements positioned at arbitrary geometry using a regular Cartesian grid of image voxels. The authors report on a variety of design choices and optimization for the creation of the generalized framework. The image reconstruction algorithm is maximum likelihood-expectation-maximization. System geometry can be specified using a simple script. Given the geometry, a symmetry seeking algorithm finds existing symmetry in the geometry with respect to the image grid to improve the memory usage/speed. Normalization is approached from a geometry independent perspective. The system matrix is computed using the Siddon's algorithm and subcrystal approach. The program is parallelized through open multiprocessing and message passing interface libraries. A wide variety of systems can be modeled using the framework. This is made possible by modeling the underlying physics and data correction, while generalizing the geometry dependent features. Application of the framework for three novel PET systems, each designed for a specific application, is presented to demonstrate the robustness of the framework in modeling PET systems of unconventional geometry. Three PET systems of unconventional geometry are studied. (1) Virtual-pinhole half-ring insert integrated into Biograph-40: although the insert device improves image quality over conventional whole-body scanner, the image quality varies depending on the position of the insert and the object. (2) Virtual-pinhole flat-panel insert integrated into Biograph-40: preliminary results from an investigation into a modular flat-panel insert are presented. (3) Plant PET system: a reconfigurable PET system for imaging plants, with resolution of greater than 3.3 mm, is shown. Using the automated symmetry seeking algorithm, the authors achieved a compression ratio of the storage and memory requirement by a factor of approximately 50 for the half-ring and flat-panel systems. For plant PET system, the compression ratio is approximately five. The ratio depends on the level of symmetry that exists in different geometries. This work brings the field closer to arbitrary geometry reconstruction. A generalized reconstruction framework can be used to validate multiple hypotheses and the effort required to investigate each system is reduced. Memory usage/speed can be improved with certain optimizations.

A generalized reconstruction framework for unconventional PET systems

PubMed Central

Mathews, Aswin John; Li, Ke; Komarov, Sergey; Wang, Qiang; Ravindranath, Bosky; O’Sullivan, Joseph A.; Tai, Yuan-Chuan

2015-01-01

Purpose: Quantitative estimation of the radionuclide activity concentration in positron emission tomography (PET) requires precise modeling of PET physics. The authors are focused on designing unconventional PET geometries for specific applications. This work reports the creation of a generalized reconstruction framework, capable of reconstructing tomographic PET data for systems that use right cuboidal detector elements positioned at arbitrary geometry using a regular Cartesian grid of image voxels. Methods: The authors report on a variety of design choices and optimization for the creation of the generalized framework. The image reconstruction algorithm is maximum likelihood-expectation–maximization. System geometry can be specified using a simple script. Given the geometry, a symmetry seeking algorithm finds existing symmetry in the geometry with respect to the image grid to improve the memory usage/speed. Normalization is approached from a geometry independent perspective. The system matrix is computed using the Siddon’s algorithm and subcrystal approach. The program is parallelized through open multiprocessing and message passing interface libraries. A wide variety of systems can be modeled using the framework. This is made possible by modeling the underlying physics and data correction, while generalizing the geometry dependent features. Results: Application of the framework for three novel PET systems, each designed for a specific application, is presented to demonstrate the robustness of the framework in modeling PET systems of unconventional geometry. Three PET systems of unconventional geometry are studied. (1) Virtual-pinhole half-ring insert integrated into Biograph-40: although the insert device improves image quality over conventional whole-body scanner, the image quality varies depending on the position of the insert and the object. (2) Virtual-pinhole flat-panel insert integrated into Biograph-40: preliminary results from an investigation into a modular flat-panel insert are presented. (3) Plant PET system: a reconfigurable PET system for imaging plants, with resolution of greater than 3.3 mm, is shown. Using the automated symmetry seeking algorithm, the authors achieved a compression ratio of the storage and memory requirement by a factor of approximately 50 for the half-ring and flat-panel systems. For plant PET system, the compression ratio is approximately five. The ratio depends on the level of symmetry that exists in different geometries. Conclusions: This work brings the field closer to arbitrary geometry reconstruction. A generalized reconstruction framework can be used to validate multiple hypotheses and the effort required to investigate each system is reduced. Memory usage/speed can be improved with certain optimizations. PMID:26233187

Prediction of the niche effect for single flat panels with or without attached sound absorbing materials.

PubMed

Sgard, Franck; Atalla, Noureddine; Nélisse, Hugues

2015-01-01

The sound transmission loss (STL) of a test sample measured in sound transmission facilities is affected by the opening in which it is located. This is called the niche effect. This paper uses a modal approach to study the STL of a rectangular plate with or without an attached porous material located inside a box-shaped niche. The porous material is modeled as a limp equivalent fluid. The proposed model is validated by comparison with finite element/boundary element computations. Using a condensation of the pressure fields in the niche, the niche effect is interpreted in terms of a modification of the modal blocked pressure fields acting on the panel induced by the front cavity and by a modification of the radiation efficiency of the panel modes due to the presence of the back cavity. The modal approach is then used to investigate the impact of (1) the presence of a porous material attached to the panel on the niche effect and (2) the niche effect on the assessment of the porous material insertion loss. A simplified model for the porous material based on a transfer matrix approach is also proposed to predict the STL of the system and its validity is discussed.

Evaluation of viewing experiences induced by curved 3D display

NASA Astrophysics Data System (ADS)

Mun, Sungchul; Park, Min-Chul; Yano, Sumio

2015-05-01

As advanced display technology has been developed, much attention has been given to flexible panels. On top of that, with the momentum of the 3D era, stereoscopic 3D technique has been combined with the curved displays. However, despite the increased needs for 3D function in the curved displays, comparisons between curved and flat panel displays with 3D views have rarely been tested. Most of the previous studies have investigated their basic ergonomic aspects such as viewing posture and distance with only 2D views. It has generally been known that curved displays are more effective in enhancing involvement in specific content stories because field of views and distance from the eyes of viewers to both edges of the screen are more natural in curved displays than in flat panel ones. For flat panel displays, ocular torsions may occur when viewers try to move their eyes from the center to the edges of the screen to continuously capture rapidly moving 3D objects. This is due in part to differences in viewing distances from the center of the screen to eyes of viewers and from the edges of the screen to the eyes. Thus, this study compared S3D viewing experiences induced by a curved display with those of a flat panel display by evaluating significant subjective and objective measures.

Experimental Investigation at Mach Number 3.0 of the Effects of Thermal Stress and Buckling on the Flutter of Four-Bay Aluminum Alloy Panels with Length-Width Ratios of 10

NASA Technical Reports Server (NTRS)

Dixon, Sidney C.; Griffith, George E.; Bohon, Herman L.

1961-01-01

Skin-stiffener aluminum alloy panels consisting of four bays, each bay having a length-width ratio of 10, were tested at a Mach number of 3.0 at dynamic pressures ranging from 1,500 psf to 5,000 psf and at stagnation temperatures from 300 F to 655 F. The panels were restrained by the supporting structure in such a manner that partial thermal expansion of the skins could occur in both the longitudinal and lateral directions. A boundary faired through the experimental flutter points consisted of a flat-panel portion, a buckled-panel portion, and a transition point at the intersection of the two boundaries. In the region where a panel must be flat when flutter occurs, an increase in panel skin temperature (or midplane compressive stress) makes the panel more susceptible to flutter. In the region where a panel must be buckled when flutter occurs, the flutter trend is reversed. This reversal in trend is attributed to the panel postbuckling behavior.

U.S. Army Aeromedical Research Laboratory Annual Progress Report, Calendar Year 1999

DTIC Science & Technology

2000-03-01

has continued basic flat panel research with the intent of transitioning the approach to applied, in-flight examination of flat panel technology...Department of Psychology was executed in CY99 for cooperative investigation of hierarchically ordered information in intelligent multifunction displays...1999 Instructional courses on fatigue management were given at the Aviation Precommand Course, the Aviation Psychology Course, the Flight Surgeon’s

Diffractive flat panel solar concentrators of a novel design.

PubMed

de Jong, Ties M; de Boer, Dick K G; Bastiaansen, Cees W M

2016-07-11

A novel design for a flat panel solar concentrator is presented which is based on a light guide with a grating applied on top that diffracts light into total internal reflection. By combining geometrical and diffractive optics the geometrical concentration ratio is optimized according to the principles of nonimaging optics, while the thickness of the device is minimized due to the use of total internal reflection.

Nonlinear bulging factor based on R-curve data

NASA Technical Reports Server (NTRS)

Jeong, David Y.; Tong, Pin

1994-01-01

In this paper, a nonlinear bulging factor is derived using a strain energy approach combined with dimensional analysis. The functional form of the bulging factor contains an empirical constant that is determined using R-curve data from unstiffened flat and curved panel tests. The determination of this empirical constant is based on the assumption that the R-curve is the same for both flat and curved panels.

Monte Carlo simulation of a quantum noise limited Čerenkov detector based on air-spaced light guiding taper for megavoltage x-ray imaging

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

Teymurazyan, A.; Rowlands, J. A.; Thunder Bay Regional Research Institute

2014-04-15

Purpose: Electronic Portal Imaging Devices (EPIDs) have been widely used in radiation therapy and are still needed on linear accelerators (Linacs) equipped with kilovoltage cone beam CT (kV-CBCT) or MRI systems. Our aim is to develop a new high quantum efficiency (QE) Čerenkov Portal Imaging Device (CPID) that is quantum noise limited at dose levels corresponding to a single Linac pulse. Methods: Recently a new concept of CPID for MV x-ray imaging in radiation therapy was introduced. It relies on Čerenkov effect for x-ray detection. The proposed design consisted of a matrix of optical fibers aligned with the incident x-raysmore » and coupled to an active matrix flat panel imager (AMFPI) for image readout. A weakness of such design is that too few Čerenkov light photons reach the AMFPI for each incident x-ray and an AMFPI with an avalanche gain is required in order to overcome the readout noise for portal imaging application. In this work the authors propose to replace the optical fibers in the CPID with light guides without a cladding layer that are suspended in air. The air between the light guides takes on the role of the cladding layer found in a regular optical fiber. Since air has a significantly lower refractive index (∼1 versus 1.38 in a typical cladding layer), a much superior light collection efficiency is achieved. Results: A Monte Carlo simulation of the new design has been conducted to investigate its feasibility. Detector quantities such as quantum efficiency (QE), spatial resolution (MTF), and frequency dependent detective quantum efficiency (DQE) have been evaluated. The detector signal and the quantum noise have been compared to the readout noise. Conclusions: Our studies show that the modified new CPID has a QE and DQE more than an order of magnitude greater than that of current clinical systems and yet a spatial resolution similar to that of current low-QE flat-panel based EPIDs. Furthermore it was demonstrated that the new CPID does not require an avalanche gain in the AMFPI and is quantum noise limited at dose levels corresponding to a single Linac pulse.« less

The features of self-assembling organic bilayers important to the formation of anisotropic inorganic materials in microgravity conditions

NASA Technical Reports Server (NTRS)

Talham, Daniel R.; Adair, James H.

2005-01-01

Materials with directional properties are opening new horizons in a variety of applications including chemistry, electronics, and optics. Structural, optical, and electrical properties can be greatly augmented by the fabrication of composite materials with anisotropic microstructures or with anisotropic particles uniformly dispersed in an isotropic matrix. Examples include structural composites, magnetic and optical recording media, photographic film, certain metal and ceramic alloys, and display technologies including flat panel displays. The new applications and the need for model particles in scientific investigations are rapidly out-distancing the ability to synthesize anisotropic particles with specific chemistries and narrowly distributed physical characteristics (e.g. size distribution, shape, and aspect ratio).

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.

Using a flat-panel detector in high resolution cone beam CT for dental imaging.

PubMed

Baba, R; Ueda, K; Okabe, M

2004-09-01

Cone beam CT (CBCT) requires a two-dimensional X-ray detector. In the several CBCT systems developed for dental imaging, detection has been by the combination of an X-ray image intensifier and charge-coupled device (CCD) camera. In this paper, we propose a new CBCT system in which the detector is of the flat-panel type and evaluate its performance in dental imaging. We developed a prototype CBCT that has a flat-panel-type detector. The detector consists of a CsI scintillator screen and a photosensor array. First, the flat panel detector and image intensifier detector were compared in terms of the signal-to-noise ratio (SNR) of projected images. We then used these data and a theoretical formula to evaluate noise in reconstructed images. Second, reconstructed images of a bar pattern phantom were obtained as a way of evaluating the spatial resolution. Then, reconstructed images of a skull phantom were obtained. The SNR of the developed system was 1.6 times as high as that of a system with an image intensifier detector of equal detector pitch. The system was capable of resolving a 0.35 mm pattern and its field of view almost completely encompassed that of an image intensifier detector which is used in dentomaxillofacial imaging. The fine spatial resolution of the detector led to images in which the structural details of a skull phantom were clearly visible. The system's isotropically fine resolution will lead to improved precision in dental diagnosis and surgery. The next stage of our research will be the development of a flat panel detector system with a high frame acquisition rate.

Projection display technology for avionics applications

NASA Astrophysics Data System (ADS)

Kalmanash, Michael H.; Tompkins, Richard D.

2000-08-01

Avionics displays often require custom image sources tailored to demanding program needs. Flat panel devices are attractive for cockpit installations, however recent history has shown that it is not possible to sustain a business manufacturing custom flat panels in small volume specialty runs. As the number of suppliers willing to undertake this effort shrinks, avionics programs unable to utilize commercial-off-the-shelf (COTS) flat panels are placed in serious jeopardy. Rear projection technology offers a new paradigm, enabling compact systems to be tailored to specific platform needs while using a complement of COTS components. Projection displays enable improved performance, lower cost and shorter development cycles based on inter-program commonality and the wide use of commercial components. This paper reviews the promise and challenges of projection technology and provides an overview of Kaiser Electronics' efforts in developing advanced avionics displays using this approach.

5-inch-size liquid crystal flat panel display evaluation test by flight simulator

NASA Astrophysics Data System (ADS)

Kawahara, Hiroyasu; Watanabe, Akira; Wakairo, Kaoru; Udagawa, Tomoyuki; Kurihara, Yoichiro

An evaluation test is conducted on the function, performance, and display format of a 5x5 inch flat panel display (FPD) in a flight simulator. The FPD utilizes a color liquid crystal panel that is compact and lightweight and has excellent visibility. The simulator evaluation test is carried out in sequence with the conventional takeoff and landing to altitude, and then conversion to STOL procedures for flight path and subsequent approach and landing. It is shown that the liquid crystal display could be employed as a satisfactory indicator for aircraft instrumentation.

Evaluation of a 15-inch widescreen OLED with sunlight-readable resistive touch panel

NASA Astrophysics Data System (ADS)

Hufnagel, Bruce D.; Tchon, Joseph L.; Bahadur, Birendra

2012-06-01

A commercially available 15-inch active-matrix organic light-emitting diode (AMOLED) television was modified to include a sunlight-readable resistive touch panel for technical evaluation with regard to a variety of rugged military and aerospace applications. By removing the circular polarizer (CP) from the AMOLED and relying on the touch panel's CP, the authors were able to minimize change in display luminance while adding touch capability and reducing reflectance.

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.

Calculated and measured stresses in simple panels subject to intense random acoustic loading including the near noise field of a turbojet engine

NASA Technical Reports Server (NTRS)

Lassiter, Leslie W; Hess, Robert W

1958-01-01

Flat 2024-t3 aluminum panels measuring 11 inches by 13 inches were tested in the near noise fields of a 4-inch air jet and turbojet engine. The stresses which were developed in the panels are compared with those calculated by generalized harmonic analysis. The calculated and measured stresses were found to be in good agreement. In order to make the stress calculations, supplementary data relating to the transfer characteristics, damping, and static response of flat and curved panels under periodic loading are necessary and were determined experimentally. In addition, an appendix containing detailed data on the near pressure field of the turbojet engine is included.

76 FR 38992 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Update to Materials...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-05

... Definitions 5/24/10 12/28/10, 75 FR 81555... Addition of four new definitions: Exterior panels, interior panels, flat wood panel coating, and tileboard. See Part III of the IBR document. * * * * * * Part E...

Low-cost modular array-field designs for flat-panel and concentrator photovoltaic systems

NASA Astrophysics Data System (ADS)

Post, H. N.; Carmichael, D. C.; Alexander, G.; Castle, J. A.

1982-09-01

Described are the design and development of low-cost, modular array fields for flat-panel and concentrator photovoltaic (PV) systems. The objective of the work was to reduce substantially the cost of the array-field Balance-of-System (BOS) subsystems and site-specific design costs as compared to previous PV installations. These subsystems include site preparation, foundations, support structures, electrical writing, grounding, lightning protection, electromagnetic interference considerations, and controls. To reduce these BOS and design costs, standardized modular (building-block) designs for flat-panel and concentrator array fields have been developed that are fully integrated and optimized for lowest life-cycle costs. Using drawings and specifications now available, these building-block designs can be used in multiples to install various size array fields. The developed designs are immediately applicable (1982) and reduce the array-field BOS costs to a fraction of previous costs.

A novel heuristic for optimization aggregate production problem: Evidence from flat panel display in Malaysia

NASA Astrophysics Data System (ADS)

Al-Kuhali, K.; Hussain M., I.; Zain Z., M.; Mullenix, P.

2015-05-01

Aim: This paper contribute to the flat panel display industry it terms of aggregate production planning. Methodology: For the minimization cost of total production of LCD manufacturing, a linear programming was applied. The decision variables are general production costs, additional cost incurred for overtime production, additional cost incurred for subcontracting, inventory carrying cost, backorder costs and adjustments for changes incurred within labour levels. Model has been developed considering a manufacturer having several product types, which the maximum types are N, along a total time period of T. Results: Industrial case study based on Malaysia is presented to test and to validate the developed linear programming model for aggregate production planning. Conclusion: The model development is fit under stable environment conditions. Overall it can be recommended to adapt the proven linear programming model to production planning of Malaysian flat panel display industry.

Enhanced solution velocity between dark and light areas with horizontal tubes and triangular prism baffles to improve microalgal growth in a flat-panel photo-bioreactor.

PubMed

Yang, Zongbo; Cheng, Jun; Xu, Xiaodan; Zhou, Junhu; Cen, Kefa

2016-07-01

Novel horizontal tubes and triangular prism (HTTP) baffles that generate flow vortices were developed to increase solution velocity between dark and light areas and thus improve microalgal growth in a flat-panel photo-bioreactor. Solution velocity, mass-transfer coefficient, and mixing time were measured with a particle-imaging velocimeter, dissolved oxygen probes, and pH probes. The solution mass-transfer coefficient increased by 30% and mixing time decreased by 21% when the HTTP baffles were used. The solution velocity between dark and light areas increased from ∼0.9cm/s to ∼3.5cm/s, resulting in a decreased dark-light cycle period to one-fourth. This enhanced flashing light effect with the HTTP baffles dramatically increased microalgae biomass yield by 70% in the flat-panel photo-bioreactor. Copyright © 2016 Elsevier Ltd. All rights reserved.

Flat panel display using Ti-Cr-Al-O thin film

DOEpatents

Jankowski, Alan F.; Schmid, Anthony P.

2002-01-01

Thin films of Ti--Cr--Al--O are used as a resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O.sub.2. Resistivity values from 10.sup.4 to 10.sup.10 Ohm-cm have been measured for Ti--Cr--Al--O film <1 .mu.m thick. The film resistivity can be discretely selected through control of the target composition and the deposition parameters. The application of Ti--Cr--Al--O as a thin film resistor has been found to be thermodynamically stable, unlike other metal-oxide films. The Ti--Cr--Al--O film can be used as a vertical or lateral resistor, for example, as a layer beneath a field emission cathode in a flat panel display; or used to control surface emissivity, for example, as a coating on an insulating material such as vertical wall supports in flat panel displays.

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.

A study of the structural-acoustic response and interior noise levels of fuselage structures

NASA Technical Reports Server (NTRS)

Koval, L. R.

1978-01-01

Models of both flat and curved fuselage panels were tested for their sound transmission characteristics. The effect of external air flow on transmission loss was simulated in a subsonic wind-tunnel. By numerically evaluating the known equations for field-incidence transmission loss of single-walled panels in a computer program, a comparison of the theory with the test results was made. As a further extension to aircraft fuselage simulation, equations for the field-incidence transmission loss of a double-walled panel were derived. Flow is shown to provide a small increase in transmission loss for a flat panel. Curvature is shown to increase transmission loss for low frequencies, while also providing a sharp decrease in transmission loss at the ring frequency of the cylindrical panel. The field-incidence transmission loss of a double-walled panel was found to be approximately twice that for a single-walled panel, with the addition of dips in the transmission loss at the air gap resonances and at the critical frequency of the internal panel.

Advanced composites structural concepts and materials technologies for primary aircraft structures. Structural response and failure analysis: ISPAN modules users manual

NASA Technical Reports Server (NTRS)

Hairr, John W.; Huang, Jui-Ten; Ingram, J. Edward; Shah, Bharat M.

1992-01-01

The ISPAN Program (Interactive Stiffened Panel Analysis) is an interactive design tool that is intended to provide a means of performing simple and self contained preliminary analysis of aircraft primary structures made of composite materials. The program combines a series of modules with the finite element code DIAL as its backbone. Four ISPAN Modules were developed and are documented. These include: (1) flat stiffened panel; (2) curved stiffened panel; (3) flat tubular panel; and (4) curved geodesic panel. Users are instructed to input geometric and material properties, load information and types of analysis (linear, bifurcation buckling, or post-buckling) interactively. The program utilizing this information will generate finite element mesh and perform analysis. The output in the form of summary tables of stress or margins of safety, contour plots of loads or stress, and deflected shape plots may be generalized and used to evaluate specific design.

Age-forming aluminum panels

NASA Technical Reports Server (NTRS)

Baxter, G. I.

1976-01-01

Contoured-stiffened 63 by 337 inch 2124 aluminum alloy panels are machined in-the-flat to make integral, tapered T-capped stringers, parallel with longitudinal centerline. Aging fixture, which includes net contour formers made from lofted contour templates, has eggcrate-like structure for use in forming and checking panels.

A true minimally invasive approach for cochlear implantation: high accuracy in cranial base navigation through flat-panel-based volume computed tomography.

PubMed

Majdani, Omid; Bartling, Soenke H; Leinung, Martin; Stöver, Timo; Lenarz, Minoo; Dullin, Christian; Lenarz, Thomas

2008-02-01

High-precision intraoperative navigation using high-resolution flat-panel volume computed tomography makes feasible the possibility of minimally invasive cochlear implant surgery, including cochleostomy. Conventional cochlear implant surgery is typically performed via mastoidectomy with facial recess to identify and avoid damage to vital anatomic landmarks. To accomplish this procedure via a minimally invasive approach--without performing mastoidectomy--in a precise fashion, image-guided technology is necessary. With such an approach, surgical time and expertise may be reduced, and hearing preservation may be improved. Flat-panel volume computed tomography was used to scan 4 human temporal bones. A drilling channel was planned preoperatively from the mastoid surface to the round window niche, providing a margin of safety to all functional important structures (e.g., facial nerve, chorda tympani, incus). Postoperatively, computed tomographic imaging and conventional surgical exploration of the drilled route to the cochlea were performed. All 4 specimens showed a cochleostomy located at the scala tympani anterior inferior to the round window. The chorda tympani was damaged in 1 specimen--this was preoperatively planned as a narrow facial recess was encountered. Using flat-panel volume computed tomography for image-guided surgical navigation, we were able to perform minimally invasive cochlear implant surgery defined as a narrow, single-channel mastoidotomy with cochleostomy. Although this finding is preliminary, it is technologically achievable.

[The future of bedside chest radiography: Comparative study of mobile flat-panels and needle-image plate storage phosphor systems].

PubMed

Bremicker, K; Gosch, D; Kahn, T; Borte, G

2015-11-01

Chest radiography is the most common diagnostic modality in intensive care units with new mobile flat-panels gaining more attention and availability in addition to the already used storage phosphor plates. Comparison of the image quality of mobile flat-panels and needle-image plate storage phosphor system in terms of bedside chest radiography. Retrospective analysis of 84 bedside chest radiographs of 42 intensive care patients (20 women, 22 men, average age: 65 years). All images were acquired during daily routine. For each patient, two images were analyzed, one from each system mentioned above. Two blinded radiologists evaluated the image quality based on ten criteria (e.g., diaphragm, heart contour, tracheal bifurcation, thoracic spine, lung structure, consolidations, foreign material, and overall impression) using a 5-point visibility scale (1 = excellent, 5 = not usable). There was no significant difference between the image quality of the two systems (p < 0.05). Overall some anatomical structures such as the diaphragm, heart, pulmonary consolidations and foreign material were considered of higher diagnostic quality compared to others, e.g., tracheal bifurcation and thoracic spine. Mobile flat-panels achieve an image quality which is as good as those of needle-image plate storage phosphor systems. In addition, they allow immediate evaluation of the image quality but in return are much more expensive in terms of purchase and maintenance.

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.

Effects of Tangential Edge Constraints on the Postbuckling Behavior of Flat and Curved Panels Subjected to Thermal and Mechanical Loads

NASA Technical Reports Server (NTRS)

Lin, W.; Librescu, L.; Nemeth, M. P.; Starnes, J. H. , Jr.

1994-01-01

A parametric study of the effects of tangential edge constraints on the postbuckling response of flat and shallow curved panels subjected to thermal and mechanical loads is presented. The mechanical loads investigated are uniform compressive edge loads and transverse lateral pressure. The temperature fields considered are associated with spatially nonuniform heating over the panels, and a linear through-the-thickness temperature gradient. The structural model is based on a higher-order transverse-shear-deformation theory of shallow shells that incorporates the effects of geometric nonlinearities, initial geometric imperfections, and tangential edge motion constraints. Results are presented for three-layer sandwich panels made from transversely isotropic materials. Simply supported panels are considered in which the tangential motion of the unloaded edges is either unrestrained, partially restrained, or fully restrained. These results focus on the effects of the tangential edge restraint on the postbuckling response. The results of this study indicate that tangentially restraining the edges of a curved panel can make the panel insensitive to initial geometric imperfections in some cases.

Collation of quarterly reports on air flat plate collectors

NASA Technical Reports Server (NTRS)

1977-01-01

The solar 2 air flat plate collectors are described. The development and fabrication of a prototype air flat plate collector subsystem containing 320 square feet of collector area are described. Three instrumented panels were completely assembled with glazing and insulation. Manufacture of the last seven prototype collectors was completed in October 1977.

Large area x-ray detectors for cargo radiography

NASA Astrophysics Data System (ADS)

Bueno, C.; Albagli, D.; Bendahan, J.; Castleberry, D.; Gordon, C.; Hopkins, F.; Ross, W.

2007-04-01

Large area x-ray detectors based on phosphors coupled to flat panel amorphous silicon diode technology offer significant advances for cargo radiologic imaging. Flat panel area detectors provide large object coverage offering high throughput inspections to meet the high flow rate of container commerce. These detectors provide excellent spatial resolution when needed, and enhanced SNR through low noise electronics. If the resolution is reduced through pixel binning, further advances in SNR are achievable. Extended exposure imaging and frame averaging enables improved x-ray penetration of ultra-thick objects, or "select-your-own" contrast sensitivity at a rate many times faster than LDAs. The areal coverage of flat panel technology provides inherent volumetric imaging with the appropriate scanning methods. Flat panel area detectors have flexible designs in terms of electronic control, scintillator selection, pixel pitch, and frame rates. Their cost is becoming more competitive as production ramps up for the healthcare, nondestructive testing (NDT), and homeland protection industries. Typically used medical and industrial polycrystalline phosphor materials such as Gd2O2S:Tb (GOS) can be applied to megavolt applications if the phosphor layer is sufficiently thick to enhance x-ray absorption, and if a metal radiator is used to augment the quantum detection efficiency and reduce x-ray scatter. Phosphor layers ranging from 0.2-mm to 1-mm can be "sandwiched" between amorphous silicon flat panel diode arrays and metal radiators. Metal plates consisting of W, Pb or Cu, with thicknesses ranging from 0.25-mm to well over 1-mm can be used by covering the entire area of the phosphor plate. In some combinations of high density metal and phosphor layers, the metal plate provides an intensification of 25% in signal due to electron emission from the plate and subsequent excitation within the phosphor material. This further improves the SNR of the system.

A high performance porous flat-plate solar collector

NASA Technical Reports Server (NTRS)

Lansing, F. L.; Clarke, V.; Reynolds, R.

1979-01-01

A solar collector employing a porous matrix as a solar absorber and heat exchanger is presented and its application in solar air heaters is discussed. The collector is composed of a metallic matrix with a porous surface which acts as a large set of cavity radiators; cold air flows through the matrix plate and exchanges heat with the thermally stratified layers of the matrix. A steady-state thermal analysis of the collector is used to determine collector temperature distributions for the cases of an opaque surface matrix with total absorption of solar energy at the surface, and a diathermanous matrix with successive solar energy absorption at each depth. The theoretical performance of the porous flat plate collector is shown to exceed greatly that of a solid flat plate collector using air as the working medium for any given set of operational conditions. An experimental collector constructed using commercially available, low cost steel wool as the matrix has been found to have thermal efficiencies from 73 to 86%.

Qualification test results for DOE solar photovoltaic flat panel procurement - PRDA 38

NASA Technical Reports Server (NTRS)

Griffith, J. S.

1980-01-01

Twelve types of prototypes modules for the DOE Photovoltaic Flat Panel Procurement (PRDA 38) were subjected to qualification tests at the Jet Propulsion Laboratory according to a new specification. Environmental exposures were carried out separately and included temperature cycling, humidity, wind simulation, and hail. The most serious problems discovered were reduced insulation resistance to ground and ground continuity of the metal frames, electrical degradation, erratic power readings, and delamination. The electrical and physical characteristics of the newly received modules are also given.

Attenuated phase-shift mask (PSM) blanks for flat panel display

NASA Astrophysics Data System (ADS)

Kageyama, Kagehiro; Mochizuki, Satoru; Yamakawa, Hiroyuki; Uchida, Shigeru

2015-10-01

The fine pattern exposure techniques are required for Flat Panel display applications as smart phone, tablet PC recently. The attenuated phase shift masks (PSM) are being used for ArF and KrF photomask lithography technique for high end pattern Semiconductor applications. We developed CrOx based large size PSM blanks that has good uniformity on optical characteristics for FPD applications. We report the basic optical characteristics and uniformity, stability data of large sized CrOx PSM blanks.

16. VIEW OF THE STATIONARY OPERATING ENGINEER CONTROL PANEL INSTALLATION. ...

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

16. VIEW OF THE STATIONARY OPERATING ENGINEER CONTROL PANEL INSTALLATION. THE PANEL CONTROLS AIR-HANDLING EQUIPMENT AND AIR PRESSURE WITHIN THE BUILDING. (10/6/69) - Rocky Flats Plant, Plutonium Manufacturing Facility, North-central section of Plant, just south of Building 776/777, Golden, Jefferson County, CO

Modeling Microalgae Productivity in Industrial-Scale Vertical Flat Panel Photobioreactors.

PubMed

Endres, Christian H; Roth, Arne; Brück, Thomas B

2018-05-01

Potentially achievable biomass yields are a decisive performance indicator for the economic viability of mass cultivation of microalgae. In this study, a computer model has been developed and applied to estimate the productivity of microalgae for large-scale outdoor cultivation in vertical flat panel photobioreactors. Algae growth is determined based on simulations of the reactor temperature and light distribution. Site-specific weather and irradiation data are used for annual yield estimations in six climate zones. Shading and reflections between opposing panels and between panels and the ground are dynamically computed based on the reactor geometry and the position of the sun. The results indicate that thin panels (≤0.05 m) are best suited for the assumed cell density of 2 g L -1 and that reactor panels should face in north-south direction. Panel spacings of 0.4-0.75 m at a panel height of 1 m appear most suitable for commercial applications. Under these preconditions, yields of around 10 kg m -2 a -1 are possible for most locations in the U.S. Only in hot climates significantly lower yields have to be expected, as extreme reactor temperatures limit overall productivity.

A semiempirical linear model of indirect, flat-panel x-ray detectors.

PubMed

Huang, Shih-Ying; Yang, Kai; Abbey, Craig K; Boone, John M

2012-04-01

It is important to understand signal and noise transfer in the indirect, flat-panel x-ray detector when developing and optimizing imaging systems. For optimization where simulating images is necessary, this study introduces a semiempirical model to simulate projection images with user-defined x-ray fluence interaction. The signal and noise transfer in the indirect, flat-panel x-ray detectors is characterized by statistics consistent with energy-integration of x-ray photons. For an incident x-ray spectrum, x-ray photons are attenuated and absorbed in the x-ray scintillator to produce light photons, which are coupled to photodiodes for signal readout. The signal mean and variance are linearly related to the energy-integrated x-ray spectrum by empirically determined factors. With the known first- and second-order statistics, images can be simulated by incorporating multipixel signal statistics and the modulation transfer function of the imaging system. To estimate the semiempirical input to this model, 500 projection images (using an indirect, flat-panel x-ray detector in the breast CT system) were acquired with 50-100 kilovolt (kV) x-ray spectra filtered with 0.1-mm tin (Sn), 0.2-mm copper (Cu), 1.5-mm aluminum (Al), or 0.05-mm silver (Ag). The signal mean and variance of each detector element and the noise power spectra (NPS) were calculated and incorporated into this model for accuracy. Additionally, the modulation transfer function of the detector system was physically measured and incorporated in the image simulation steps. For validation purposes, simulated and measured projection images of air scans were compared using 40 kV∕0.1-mm Sn, 65 kV∕0.2-mm Cu, 85 kV∕1.5-mm Al, and 95 kV∕0.05-mm Ag. The linear relationship between the measured signal statistics and the energy-integrated x-ray spectrum was confirmed and incorporated into the model. The signal mean and variance factors were linearly related to kV for each filter material (r(2) of signal mean to kV: 0.91, 0.93, 0.86, and 0.99 for 0.1-mm Sn, 0.2-mm Cu, 1.5-mm Al, and 0.05-mm Ag, respectively; r(2) of signal variance to kV: 0.99 for all four filters). The comparison of the signal and noise (mean, variance, and NPS) between the simulated and measured air scan images suggested that this model was reasonable in predicting accurate signal statistics of air scan images using absolute percent error. Overall, the model was found to be accurate in estimating signal statistics and spatial correlation between the detector elements of the images acquired with indirect, flat-panel x-ray detectors. The semiempirical linear model of the indirect, flat-panel x-ray detectors was described and validated with images of air scans. The model was found to be a useful tool in understanding the signal and noise transfer within indirect, flat-panel x-ray detector systems.

Countering Beam Divergence Effects with Focused Segmented Scintillators for High DQE Megavoltage Active Matrix Imagers

PubMed Central

Liu, Langechuan; Antonuk, Larry E; Zhao, Qihua; El-Mohri, Youcef; Jiang, Hao

2012-01-01

The imaging performance of active matrix flat-panel imagers designed for megavoltage imaging (MV AMFPIs) is severely constrained by relatively low x-ray detection efficiency, which leads to a detective quantum efficiency (DQE) of only ~1%. Previous theoretical and empirical studies by our group have demonstrated the potential for addressing this constraint through utilization of thick, two-dimensional, segmented scintillators with optically isolated crystals. However, this strategy is constrained by degradation of high-frequency DQE resulting from spatial resolution loss at locations away from the central beam axis due to oblique incidence of radiation. To address this challenge, segmented scintillators constructed so that the crystals are individually focused toward the radiation source are proposed and theoretically investigated. The study was performed using Monte Carlo simulations of radiation transport to examine the modulation transfer function and DQE of focused segmented scintillators with thicknesses ranging from 5 to 60 mm. The results demonstrate that, independent of scintillator thickness, the introduction of focusing largely restores spatial resolution and DQE performance otherwise lost in thick, unfocused segmented scintillators. For the case of a 60 mm thick BGO scintillator and at a location 20 cm off the central beam axis, use of focusing improves DQE by up to a factor of ~130 at non-zero spatial frequencies. The results also indicate relatively robust tolerance of such scintillators to positional displacements, of up to 10 cm in the source-to-detector direction and 2 cm in the lateral direction, from their optimal focusing position, which could potentially enhance practical clinical use of focused segmented scintillators in MV AMFPIs. PMID:22854009

Far-IR transparency and dynamic infrared signature control with novel conducting polymer systems

NASA Astrophysics Data System (ADS)

Chandrasekhar, Prasanna; Dooley, T. J.

1995-09-01

Materials which possess transparency, coupled with active controllability of this transparency in the infrared (IR), are today an increasingly important requirement, for varied applications. These applications include windows for IR sensors, IR-region flat panel displays used in camouflage as well as in communication and sight through night-vision goggles, coatings with dynamically controllable IR-emissivity, and thermal conservation coatings. Among stringent requirements for these applications are large dynamic ranges (color contrast), 'multi-color' or broad-band characteristics, extended cyclability, long memory retention, matrix addressability, small area fabricability, low power consumption, and environmental stability. Among materials possessing the requirements for variation of IR signature, conducting polymers (CPs) appear to be the only materials with dynamic, actively controllable signature and acceptable dynamic range. Conventional CPs such as poly(alkyl thiophene), poly(pyrrole) or poly(aniline) show very limited dynamic range, especially in the far-IR, while also showing poor transparency. We have developed a number of novel CP systems ('system' implying the CP, the selected dopant, the synthesis method, and the electrolyte) with very wide dynamic range (up to 90% in both important IR regions, 3 - 5 (mu) and 8 - 12 (mu) ), high cyclability (to 105 cycles with less than 10% optical degradation), nearly indefinite optical memory retention, matrix addressability of multi-pixel displays, very wide operating temperature and excellent environmental stability, low charge capacity, and processability into areas from less than 1 mm2 to more than 100 cm2. The criteria used to design and arrive at these CP systems, together with representative IR signature data, are presented in this paper.

An investigation of signal performance enhancements achieved through innovative pixel design across several generations of indirect detection, active matrix, flat-panel arrays

PubMed Central

Antonuk, Larry E.; Zhao, Qihua; El-Mohri, Youcef; Du, Hong; Wang, Yi; Street, Robert A.; Ho, Jackson; Weisfield, Richard; Yao, William

2009-01-01

Active matrix flat-panel imager (AMFPI) technology is being employed for an increasing variety of imaging applications. An important element in the adoption of this technology has been significant ongoing improvements in optical signal collection achieved through innovations in indirect detection array pixel design. Such improvements have a particularly beneficial effect on performance in applications involving low exposures and∕or high spatial frequencies, where detective quantum efficiency is strongly reduced due to the relatively high level of additive electronic noise compared to signal levels of AMFPI devices. In this article, an examination of various signal properties, as determined through measurements and calculations related to novel array designs, is reported in the context of the evolution of AMFPI pixel design. For these studies, dark, optical, and radiation signal measurements were performed on prototype imagers incorporating a variety of increasingly sophisticated array designs, with pixel pitches ranging from 75 to 127 μm. For each design, detailed measurements of fundamental pixel-level properties conducted under radiographic and fluoroscopic operating conditions are reported and the results are compared. A series of 127 μm pitch arrays employing discrete photodiodes culminated in a novel design providing an optical fill factor of ∼80% (thereby assuring improved x-ray sensitivity), and demonstrating low dark current, very low charge trapping and charge release, and a large range of linear signal response. In two of the designs having 75 and 90 μm pitches, a novel continuous photodiode structure was found to provide fill factors that approach the theoretical maximum of 100%. Both sets of novel designs achieved large fill factors by employing architectures in which some, or all of the photodiode structure was elevated above the plane of the pixel addressing transistor. Generally, enhancement of the fill factor in either discrete or continuous photodiode arrays was observed to result in no degradation in MTF due to charge sharing between pixels. While the continuous designs exhibited relatively high levels of charge trapping and release, as well as shorter ranges of linearity, it is possible that these behaviors can be addressed through further refinements to pixel design. Both the continuous and the most recent discrete photodiode designs accommodate more sophisticated pixel circuitry than is present on conventional AMFPIs – such as a pixel clamp circuit, which is demonstrated to limit signal saturation under conditions corresponding to high exposures. It is anticipated that photodiode structures such as the ones reported in this study will enable the development of even more complex pixel circuitry, such as pixel-level amplifiers, that will lead to further significant improvements in imager performance. PMID:19673228

High-performance 4x4-inch AMLCD for avionic applications

NASA Astrophysics Data System (ADS)

Syroid, Daniel D.; Hansen, Glenn A.; Boling, Ed

1996-05-01

There is a need for high performance flat panel displays to replace and upgrade the electromechanical flight indicators and CRT based displays used in the cockpits of many older aircraft that are in active service today. The need for replacement of these older generation instruments is well known in the industry and was discussed in a previous paper by Duane Grave of Rockwell Collins. Furthermore, because of the limited activity in new aircraft development today, the need to upgrade existing aircraft avionics is accelerating. Many of the electromechanical instruments currently provide flight indications to the pilot and include horizontal situation (HSI) and attitude director indicators (ADI). These instruments are used on both military and commercial aircraft. The indicators are typically housed in a 5ATI case that slides into a 5 inch square opening in the cockpit. Image Quest has developed a 4 by 4 inch active area, flight quality, high resolution, full color, high luminance, wide temperature range display module based on active matrix liquid crystal display (AMLCD) technology that has excellent contrast in full sunlight. The display module is well suited for use in electronic instruments to replace or upgrade the electro-mechanical 5ATI flight indicators. THe AMLCD based display offers greatly improved display format flexibility, operating reliability and display contrast in all ambient lighting conditions as well as significant short and long term cost of ownership advantages.

A novel technique for ventriculoperitoneal shunting by flat panel detector CT-guided real-time fluoroscopy

PubMed Central

Kobayashi, Shinya; Ishikawa, Tatsuya; Mutoh, Tatsushi; Hikichi, Kentaro; Suzuki, Akifumi

2012-01-01

Background: Surgical placement of a ventriculoperitoneal shunt (VPS) is the main strategy to manage hydrocephalus. However, the failure rate associated with placement of ventricular catheters remains high. Methods: A hybrid operating room, equipped with a flat-panel detector digital subtraction angiography system containing C-arm cone-beam computed tomography (CB-CT) imaging, has recently been developed and utilized to assist neurosurgical procedures. We have developed a novel technique using intraoperative fluoroscopy and a C-arm CB-CT system to facilitate accurate placement of a VPS. Results: Using this novel technique, 39 consecutive ventricular catheters were placed accurately, and no ventricular catheter failures were experienced during the follow-up period. Only two patients experienced obstruction of the VPS, both of which occurred in the extracranial portion of the shunt system. Conclusion: Surgical placement of a VPS assisted by flat panel detector CT-guided real-time fluoroscopy enabled accurate placement of ventricular catheters and was associated with a decreased need for shunt revision. PMID:23226605

Image reconstruction in cone-beam CT with a spherical detector using the BPF algorithm

NASA Astrophysics Data System (ADS)

Zuo, Nianming; Zou, Yu; Jiang, Tianzi; Pan, Xiaochuan

2006-03-01

Both flat-panel detectors and cylindrical detectors have been used in CT systems for data acquisition. The cylindrical detector generally offers a sampling of a transverse image plane more uniformly than does a flat-panel detector. However, in the longitudinal dimension, the cylindrical and flat-panel detectors offer similar sampling of the image space. In this work, we investigate a detector of spherical shape, which can yield uniform sampling of the 3D image space because the solid angle subtended by each individual detector bin remains unchanged. We have extended the backprojection-filtration (BPF) algorithm, which we have developed previously for cone-beam CT, to reconstruct images in cone-beam CT with a spherical detector. We also conduct computer-simulation studies to validate the extended BPF algorithm. Quantitative results in these numerical studies indicate that accurate images can be obtained from data acquired with a spherical detector by use of our extended BPF cone-beam algorithms.

Fabrication of Electrophoretic Display Driven by Membrane Switch Array

NASA Astrophysics Data System (ADS)

Senda, Kazuo; Usui, Hiroaki

2010-04-01

Electrophoretic devices (EPDs) and organic light-emitting diodes (OLEDs) have potential application in a large-area flexible displays, such as digital signage. For this purpose, a new backplane is capable of driving a large unit is required instead of thin-film transistors. In this paper we describe the fabrication of a membrane switch array suitable for driving large-scale flat-panel displays. An array of membrane switches was prepared using flexible printed circuit (FPC) technology of polyimide films, by combining low-temperature processes of lamination and copper electroplating methods. An array of 256 matrix switches with a pixel size of 7 mm2 was prepared to drive the EPD front panel. The switches were driven at a voltage of about 40 V and a frequency of 10 Hz. The operation characteristics agreed well with the result of the theoretical calculation. The calculation also suggested that driving voltage can be lowered by increasing pixel size. The contact resistance of the membrane switch was as low as 0.2 Ω, which implies the wide applicability of this device for driving a variety of elements.

PANDA2: Program for Minimum Weight Design of Stiffened, Composite, Locally Buckled Panels

DTIC Science & Technology

1986-09-01

a flat panel or a panel that spans less than about 45 degrees of circumference. However, in PANDA2 complete cylindrical shells can be treated by the...compression and that corresponding to maximum in-plane shear. It is usually best to treat complete cylindrical shells in this way rather than try to set up a...to treat panels, not complete cylindrical shells. Therefore, it is best applied to panels. In PANDA2 the curved edges of a cylindrical panel lie in

A panel method study of vortex sheets with special emphasis on sheets of axisymmetric geometry. M.S. Thesis

NASA Technical Reports Server (NTRS)

Sugioka, I.; Widnall, S. E.

1985-01-01

The self induced evolution of a vortex sheet was simulated by modeling the sheet using an integration of discrete elements of vorticity. Replacing small sections of a vortex sheet by flat panels of constant vorticity is found to reproduce more accurately the initial conditions for the Lagrangian simulation technique than replacement by point vortices. The flat panel method for the vortex sheet was then extended to model axisymmetric vortex sheets. The local and far field velocities induced by the axisymmetric panels were obtained using matched asymptotic analysis, and some of the uncertainties involved in other models of the axisymmetric vortex sheet have been eliminated. One important result of this analysis is the determination of the proper choice of core size for a circular vortex filament which may replace a section of an axisymmetric vortex sheet. Roll-up of both two dimensional and axisymmetric vortex sheets was computed using the panel methods developed in the report.

Multiple-Flat-Panel System Displays Multidimensional Data

NASA Technical Reports Server (NTRS)

Gundo, Daniel; Levit, Creon; Henze, Christopher; Sandstrom, Timothy; Ellsworth, David; Green, Bryan; Joly, Arthur

2006-01-01

The NASA Ames hyperwall is a display system designed to facilitate the visualization of sets of multivariate and multidimensional data like those generated in complex engineering and scientific computations. The hyperwall includes a 77 matrix of computer-driven flat-panel video display units, each presenting an image of 1,280 1,024 pixels. The term hyperwall reflects the fact that this system is a more capable successor to prior computer-driven multiple-flat-panel display systems known by names that include the generic term powerwall and the trade names PowerWall and Powerwall. Each of the 49 flat-panel displays is driven by a rack-mounted, dual-central-processing- unit, workstation-class personal computer equipped with a hig-hperformance graphical-display circuit card and with a hard-disk drive having a storage capacity of 100 GB. Each such computer is a slave node in a master/ slave computing/data-communication system (see Figure 1). The computer that acts as the master node is similar to the slave-node computers, except that it runs the master portion of the system software and is equipped with a keyboard and mouse for control by a human operator. The system utilizes commercially available master/slave software along with custom software that enables the human controller to interact simultaneously with any number of selected slave nodes. In a powerwall, a single rendering task is spread across multiple processors and then the multiple outputs are tiled into one seamless super-display. It must be noted that the hyperwall concept subsumes the powerwall concept in that a single scene could be rendered as a mosaic image on the hyperwall. However, the hyperwall offers a wider set of capabilities to serve a different purpose: The hyperwall concept is one of (1) simultaneously displaying multiple different but related images, and (2) providing means for composing and controlling such sets of images. In place of elaborate software or hardware crossbar switches, the hyperwall concept substitutes reliance on the human visual system for integration, synthesis, and discrimination of patterns in complex and high-dimensional data spaces represented by the multiple displayed images. The variety of multidimensional data sets that can be displayed on the hyperwall is practically unlimited. For example, Figure 2 shows a hyperwall display of surface pressures and streamlines from a computational simulation of airflow about an aerospacecraft at various Mach numbers and angles of attack. In this display, Mach numbers increase from left to right and angles of attack increase from bottom to top. That is, all images in the same column represent simulations at the same Mach number, while all images in the same row represent simulations at the same angle of attack. The same viewing transformations and the same mapping from surface pressure to colors were used in generating all the images.

Monte Carlo simulation of a novel water-equivalent electronic portal imaging device using plastic scintillating fibers.

PubMed

Teymurazyan, A; Pang, G

2012-03-01

Most electronic portal imaging devices (EPIDs) developed so far use a thin Cu plate/phosphor screen to convert x-ray energies into light photons, while maintaining a high spatial resolution. This results in a low x-ray absorption and thus a low quantum efficiency (QE) of approximately 2-4% for megavoltage (MV) x-rays. A significant increase of QE is desirable for applications such as MV cone-beam computed tomography (MV-CBCT). Furthermore, the Cu plate/phosphor screen contains high atomic number (high-Z) materials, resulting in an undesirable over-response to low energy x-rays (due to photoelectric effect) as well as high energy x-rays (due to pair production) when used for dosimetric verification. Our goal is to develop a new MV x-ray detector that has a high QE and uses low-Z materials to overcome the obstacles faced by current MV x-ray imaging technologies. A new high QE and low-Z EPID is proposed. It consists of a matrix of plastic scintillating fibers embedded in a water-equivalent medium and coupled to an optically sensitive 2D active matrix flat panel imager (AMFPI) for image readout. It differs from the previous approach that uses segmented crystalline scintillators made of higher density and higher atomic number materials to detect MV x-rays. The plastic scintillating fibers are focused toward the x-ray source to avoid image blurring due to oblique incidence of off-axis x-rays. When MV x-rays interact with the scintillating fibers in the detector, scintillation light will be produced. The light photons produced in a fiber core and emitted within the acceptance angle of the fiber will be guided toward the AMFPI by total internal reflection. A Monte Carlo simulation has been used to investigate imaging and dosimetric characteristics of the proposed detector under irradiation of MV x-rays. Properties, such as detection efficiency, modulation transfer function, detective quantum efficiency (DQE), energy dependence of detector response, and water-equivalence of dose response have been investigated. It has been found that the zero frequency DQE of the proposed detector can be up to 37% at 6 MV. The detector, also, is water-equivalent with a relatively uniform response to different energy x-rays as compared to current EPIDs. The results of our simulations show that, using plastic scintillating fibers, it is possible to construct a water-equivalent EPID that has a better energy response and a higher detection efficiency than current flat panel based EPIDs.

Advanced manufacturing development of a composite empennage component for L-1011 aircraft

NASA Technical Reports Server (NTRS)

1978-01-01

Work continued toward the development of tooling and processing concepts required for a cocured hat/skin cover assembly. A plan was developed and implemented to develop the process for using preimpregnated T300/5208 with a resin content of 34 + or - 2 percent by weight. Use of this material results in a simplified laminating process because removal by bleeding or prebleeding is no longer required. The approach to this task basically consists of fabricating and testing flat laminated panels and simulated structural panels to verify known processing techniques relative to end-laminate quality. The flat panels were used to determine air bleeding arrangement and required cure cycle. Single and multihat-stiffened panels were fabricated using the established air bleeding arrangement and cure cycle with the resulting cured parts yielding excellent correlation of ply thickness with all surfaces clear of porosity and voids.

Use of Glass Reinforced Concrete (GRC) as a substrate for photovoltaic modules

NASA Technical Reports Server (NTRS)

Eirls, J. L.

1980-01-01

A substrate for flat plate photovoltaic solar panel arrays using a glass fiber reinforced concrete (GRC) material was developed. The installed cost of this GRC panel is 30% less than the cost goal of the Near Term Low-Cost Flat Plate Photovoltaic Solar Array Program. The 4 ft by 8 ft panel is fabricated from readily available inexpensive materials, weighs a nominal 190 lbs., has exceptionally good strength and durability properties (rigid and resists weathering), is amenable to mass production and is easily installed on simple mountings. Solar cells are encapsulated in ethylene/vinyl acetate with Tedlar backing and Korad cover film. The laminates are attached to the GRC substrate with acrylic transfer tape and edge sealed with silicone RTV adhesive.

Hoop Tensile Characterization Of SiC/SiC Cylinders Fabricated From 2D Fabric

NASA Technical Reports Server (NTRS)

Verrilli, Michael J.; Yun, HeeMann; DiCarlo, James A.; Barnett, Terry R.

2002-01-01

Tensile stress-strain properties in the hoop direction were obtained for 100-mm diameter SiC/SiC cylinders using ring specimens machined from the cylinder ends. The cylinders were fabricated from 2D balanced fabric with several material variants, including wall thickness (6, 8, and 12 plies), Sic fiber type (Sylramic, Sylramic-iBN, Hi-Nicalon, and Hi-Nicalon S), fiber sizing type, and matrix type (full CVI Sic, and partial CVI plus melt-infiltrated SiC-Si). Fiber ply splices existed in the all the hoops. Tensile hoop measurements were made at room temperature and 1200 C using hydrostatic ring test facilities. The hoop results are compared with in-plane data measured on flat panels using same material variants, but containing no splices.

Postbuckling analysis of shear deformable composite flat panels taking into account geometrical imperfections

NASA Technical Reports Server (NTRS)

Librescu, L.; Stein, M.

1990-01-01

The effects of initial geometrical imperfections on the postbuckling response of flat laminated composite panels to uniaxial and biaxial compressive loading are investigated analytically. The derivation of the mathematical model on the basis of first-order transverse shear deformation theory is outlined, and numerical results for perfect and imperfect, single-layer and three-layer square plates with free-free, clamped-clamped, or free-clamped edges are presented in graphs and briefly characterized. The present approach is shown to be more accurate than analyses based on the classical Kirchhoff plate model.

Examination of optimal upgrade timing and best value: DoD acquisition of commercial vs. military custom flat panel displays

NASA Astrophysics Data System (ADS)

Lippitz, Michael J.

1999-08-01

This paper proposes a framework for quantitatively balancing the costs, benefits, and risks of alternate upgrade strategies, with Department of Defense (DoD) acquisition of flat panel display as an example. A key issue in DoD Acquisition Reform is the rapid product turnover in commercial markets and the difficulties DoD has traditionally faced in adopting these advances in a timely manner. This paper aims to clarify when commercial technology represents 'best value' to DoD.

Flat panel displays in the helmet-mounted display

NASA Astrophysics Data System (ADS)

Bartlett, Christopher T.; Freeman, Jonathan P.

2002-08-01

The Helmet Mounted Display has been in development for over 25 years and with few exceptions those systems in service have incorporated a miniature Cathode Ray Tube as the display source. The exceptions have been the use of Light Emitting Diodes in Helmet Sighting displays. The argument for Flat Panel Displays has been well rehearsed and this paper provides a summary of the available technologies but with a rationale for a decision to use Reflective Liquid Crystal devices. The Paper then describes sources of illumination and derives the luminance required from that source.

Active control of panel vibrations induced by boundary-layer flow

NASA Technical Reports Server (NTRS)

Chow, Pao-Liu

1991-01-01

Some problems in active control of panel vibration excited by a boundary layer flow over a flat plate are studied. In the first phase of the study, the optimal control problem of vibrating elastic panel induced by a fluid dynamical loading was studied. For a simply supported rectangular plate, the vibration control problem can be analyzed by a modal analysis. The control objective is to minimize the total cost functional, which is the sum of a vibrational energy and the control cost. By means of the modal expansion, the dynamical equation for the plate and the cost functional are reduced to a system of ordinary differential equations and the cost functions for the modes. For the linear elastic plate, the modes become uncoupled. The control of each modal amplitude reduces to the so-called linear regulator problem in control theory. Such problems can then be solved by the method of adjoint state. The optimality system of equations was solved numerically by a shooting method. The results are summarized.

Display Techniques for Advanced Crew Stations (DTACS). Phase 1. Display Techniques Study.

DTIC Science & Technology

1984-03-01

26 3.1.3 Off Screen Displays .. ................... 27 3.1.4 Flat Panel Displays. .. ................. 27 3.2 FORMAT REQUIREMENTS...Head-Up Display ....... .................... ... 96 4.5.2 Display Panel .... ................. 98 4.5.3 RGB Calligraphic Display ................ 99...117 3.4 VOICE WARNING/RESPONSE TECHNOLOGY .............. . i.117 5.5 TOUCH PANEL TECHNOLOGY ..... ................ ... 118 5.6

Evaluating the warping of laminated particleboard panels

Treesearch

Zhiyong Cai

2004-01-01

Laminated wood composites have been used widely in the secondary manufacturing processes in the wood panel industries. Warping, which is defined as the out-of-plane deformation of an initially flat panel, is a longstanding problem associated with the use of laminated wood composites. The mechanism of warping is still not fully understood. A new two- dimensional warping...

Nanoparticle Filtration in a RTM Processed Epoxy/Carbon Fiber Composite

NASA Technical Reports Server (NTRS)

Miller, Sandi G.; Micham, Logan; Copa, Christine C.; Criss, James M., Jr.; Mintz, Eric A.

2011-01-01

Several epoxy matrix composite panels were fabricated by resin transfer molding (RTM) E862/W resin onto a triaxially braided carbon fiber pre-form. Nanoparticles including carbon nanofiber, synthetic clay, and functionalized graphite were dispersed in the E862 matrix, and the extent of particle filtration during processing was characterized. Nanoparticle dispersion in the resin flashing on both the inlet and outlet edges of the panel was compared by TEM. Variation in physical properties such as Tg and moisture absorption throughout the panel were also characterized. All nanoparticle filled panels showed a decrease in Tg along the resin flow path across the panel, indicating nanoparticle filtration, however there was little change in moisture absorption. This works illustrates the need to obtain good nano-particle dispersion in the matrix resin to prevent particle agglomeration and hence particle filtration in the resultant polymer matrix composites (PMC).

Deformation behavior of welded steel sandwich panels under quasi-static loading

DOT National Transportation Integrated Search

2011-03-01

This report describes engineering studies that were conducted to examine the deformation behavior of flat, welded steel sandwich panels under two quasi-static loading conditions: (1) uniaxial compression; and (2) bending with an indenter. Testing and...

29. INTERIOR VIEW TO THE NORTHEAST OF CONTROL PANEL AND ...

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

29. INTERIOR VIEW TO THE NORTHEAST OF CONTROL PANEL AND VIEWING WINDOW IN ROOM 105, THE CONTROL ROOM. - Nevada Test Site, Pluto Facility, Disassembly Building, Area 26, Wahmonie Flats, Cane Spring Road, Mercury, Nye County, NV

Evaluation of imaging quality for flat-panel detector based low dose C-arm CT system

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

Seo, Chang-Woo; Cha, Bo Kyung; Jeon, Sungchae

The image quality associated with the extent of the angle of gantry rotation, the number of projection views, and the dose of X-ray radiation was investigated in flat-panel detector (FPD) based C-arm cone-beam computed tomography (CBCT) system for medical applications. A prototype CBCT system for the projection acquisition used the X-ray tube (A-132, Varian inc.) having rhenium-tungsten molybdenum target and flat panel a-Si X-ray detector (PaxScan 4030CB, Varian inc.) having a 397 x 298 mm active area with 388 μm pixel pitch and 1024 x 768 pixels in 2 by 2 binning mode. The performance comparison of X-ray imaging qualitymore » was carried out using the Feldkamp, Davis, and Kress (FDK) reconstruction algorithm between different conditions of projection acquisition. In this work, head-and-dental (75 kVp/20 mA) and chest (90 kVp/25 mA) phantoms were used to evaluate the image quality. The 361 (30 fps x 12 s) projection data during 360 deg. gantry rotation with 1 deg. interval for the 3D reconstruction were acquired. Parke weighting function were applied to handle redundant data and improve the reconstructed image quality in a mobile C-arm system with limited rotation angles. The reconstructed 3D images were investigated for comparison of qualitative image quality in terms of scan protocols (projection views, rotation angles and exposure dose). Furthermore, the performance evaluation in image quality will be investigated regarding X-ray dose and limited projection data for a FPD based mobile C-arm CBCT system. (authors)« less

Radiation dose reduction using a CdZnTe-based computed tomography system: Comparison to flat-panel detectors

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

Le, Huy Q.; Ducote, Justin L.; Molloi, Sabee

2010-03-15

Purpose: Although x-ray projection mammography has been very effective in early detection of breast cancer, its utility is reduced in the detection of small lesions that are occult or in dense breasts. One drawback is that the inherent superposition of parenchymal structures makes visualization of small lesions difficult. Breast computed tomography using flat-panel detectors has been developed to address this limitation by producing three-dimensional data while at the same time providing more comfort to the patients by eliminating breast compression. Flat panels are charge integrating detectors and therefore lack energy resolution capability. Recent advances in solid state semiconductor x-ray detectormore » materials and associated electronics allow the investigation of x-ray imaging systems that use a photon counting and energy discriminating detector, which is the subject of this article. Methods: A small field-of-view computed tomography (CT) system that uses CdZnTe (CZT) photon counting detector was compared to one that uses a flat-panel detector for different imaging tasks in breast imaging. The benefits afforded by the CZT detector in the energy weighting modes were investigated. Two types of energy weighting methods were studied: Projection based and image based. Simulation and phantom studies were performed with a 2.5 cm polymethyl methacrylate (PMMA) cylinder filled with iodine and calcium contrast objects. Simulation was also performed on a 10 cm breast specimen. Results: The contrast-to-noise ratio improvements as compared to flat-panel detectors were 1.30 and 1.28 (projection based) and 1.35 and 1.25 (image based) for iodine over PMMA and hydroxylapatite over PMMA, respectively. Corresponding simulation values were 1.81 and 1.48 (projection based) and 1.85 and 1.48 (image based). Dose reductions using the CZT detector were 52.05% and 49.45% for iodine and hydroxyapatite imaging, respectively. Image-based weighting was also found to have the least beam hardening effect. Conclusions: The results showed that a CT system using an energy resolving detector reduces the dose to the patient while maintaining image quality for various breast imaging tasks.« less

A semi active telescope for the French PRONAOS submillimetric mission

NASA Astrophysics Data System (ADS)

Duran, M.; Luquet, P.; Buisson, F.; Cousin, B.

1991-09-01

The basic design of the different units constituting the full CFRP telescope for the PRONAOS submillimetric mission is described. The alignment technique is discussed, and results of optical performance measurements are presented. The instrumentation comprising the telescope consists of a reference CFRP box made of two floor sandwich panels distanced by a frame of flat sandwich panels. It provides all the mechanical interfaces internal to the telescope as well as all those needed with the gondola. The secondary structure is also made from CFRP beams organized in a framework which provides the fixations for the thermal protection panels and which ends in an electroactuated aperture door. The PRONAOS telescope's deployed configuration is illustrated. The adequacy of the semiactive mirror concept to meet very low areal mass while obtaining ultimate surface accuracy in the submillimeter wavelength domain is demonstrated.

Visual and ocular effects from the use of flat-panel displays.

PubMed

Porcar, Esteban; Pons, Alvaro M; Lorente, Amalia

2016-01-01

To evaluate the prevalence of eye symptoms in a non-presbyopic population of video display unit (VDU) users with flat-panel displays. One hundred and sixteen VDU users with flat-panel display from an urban population participated in the study; their ages ranging from 20 to 34y. There were 60 females and 56 males. An eye examination to rule out the presence of significant uncorrected refractive errors, general binocular dysfunctions and eye conditions was carried out. In order to determine and quantify the type and nature of eye symptoms, participants were asked to answer written questionnaire and the results were grouped by gender, age and number of hours a day spent using a VDU. Seventy-two percent of participants reported eye symptoms related to VDU use. Eye symptoms from moderate-to-severe were found in 23% of participants. The main symptom was moderate-to-severe tired eyes (14%); followed by sensitivity to bright lights (12%), blurred vision at far distances (10%), eyestrain or dry eye or irritated or burning eyes (9%), difficulty in refocusing from one distance to another or headache (8%) and blurred vision at near or intermediate distances (<4%). Eye symptoms were greater among females (P=0.005) and increased with VDU use, markedly above 6h spent using a VDU in a typical day (P=0.01). Significant eye symptoms relate to VDU use often occur and should not be underestimated. The increasing use of electronic devices with flat-panel display should prompt users to take appropriate measures to prevent or to relieve the eye symptoms arising from their use.

Technical Note: A Feasibility Study of Using the Flat Panel Detector on Linac for the kV X-ray Generator Test.

PubMed

Cai, Bin; Dolly, Steven; Kamal, Gregory; Yaddanapudi, Sridhar; Sun, Baozhou; Goddu, S Murty; Mutic, Sasa; Li, Hua

2018-04-28

To investigate the feasibility of using kV flat panel detector on linac for consistency evaluations of kV X-ray generator performance. An in-house designed aluminum (Al) array phantom with six 9×9 cm 2 square regions having various thickness was proposed and used in this study. Through XML script-driven image acquisition, kV images with various acquisition settings were obtained using the kV flat panel detector. Utilizing pre-established baseline curves, the consistency of X-ray tube output characteristics including tube voltage accuracy, exposure accuracy and exposure linearity were assessed through image quality assessment metrics including ROI mean intensity, ROI standard deviation (SD) and noise power spectrums (NPS). The robustness of this method was tested on two linacs for a three-month period. With the proposed method, tube voltage accuracy can be verified through conscience check with a 2% tolerance and 2 kVp intervals for forty different kVp settings. The exposure accuracy can be tested with a 4% consistency tolerance for three mAs settings over forty kVp settings. The exposure linearity tested with three mAs settings achieved a coefficient of variation (CV) of 0.1. We proposed a novel approach that uses the kV flat panel detector available on linac for X-ray generator test. This approach eliminates the inefficiencies and variability associated with using third party QA detectors while enabling an automated process. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Draft standard for color AMLCDs in U.S. military aircraft

NASA Astrophysics Data System (ADS)

Hopper, Darrel G.; Dolezal, William K.; Schur, Keith; Liccione, John W.

1994-06-01

Flight instruments have begun to use color active liquid crystal displays (AMLCDs), signaling the beginning of a significant transition from electromechanical and cathode ray tube display designs to AMLCD designs. We have the opportunity with this new technology to establish common products capable of meeting user requirements for sunlight-readable, color and gray scale-capable, high-pixel-count, flat-panel displays for weapon systems. The Wright Laboratory is leading the development of standard and specification documentation for this new generation of display modules based on requirements for U.S. military aircraft. These requirements are similar in many ways to those of both the civil aviation and automotive industries. Accordingly, commonality with these applications is incorporated, where possible, along with the requirements for all military combat applications. Industry and government organizations are involved in this process through workshops and draft review processes. Military procurement specifications for combat system applications may use this information as a source of recommended best practice for this new generation of digital flat panel displays. The draft standard will be revised based upon continuing feedback by early 1995.

Deformation behavior of welded steel sandwich panels under quasi-static loading

DOT National Transportation Integrated Search

2011-03-16

This paper summarizes basic research (i.e., testing and analysis) : conducted to examine the deformation behavior of flat-welded : steel sandwich panels under two types of quasi-static loading: : (1) uniaxial compression; and (2) bending through an i...

Design and image-quality performance of high resolution CMOS-based X-ray imaging detectors for digital mammography

NASA Astrophysics Data System (ADS)

Cha, B. K.; Kim, J. Y.; Kim, Y. J.; Yun, S.; Cho, G.; Kim, H. K.; Seo, C.-W.; Jeon, S.; Huh, Y.

2012-04-01

In digital X-ray imaging systems, X-ray imaging detectors based on scintillating screens with electronic devices such as charge-coupled devices (CCDs), thin-film transistors (TFT), complementary metal oxide semiconductor (CMOS) flat panel imagers have been introduced for general radiography, dental, mammography and non-destructive testing (NDT) applications. Recently, a large-area CMOS active-pixel sensor (APS) in combination with scintillation films has been widely used in a variety of digital X-ray imaging applications. We employed a scintillator-based CMOS APS image sensor for high-resolution mammography. In this work, both powder-type Gd2O2S:Tb and a columnar structured CsI:Tl scintillation screens with various thicknesses were fabricated and used as materials to convert X-ray into visible light. These scintillating screens were directly coupled to a CMOS flat panel imager with a 25 × 50 mm2 active area and a 48 μm pixel pitch for high spatial resolution acquisition. We used a W/Al mammographic X-ray source with a 30 kVp energy condition. The imaging characterization of the X-ray detector was measured and analyzed in terms of linearity in incident X-ray dose, modulation transfer function (MTF), noise-power spectrum (NPS) and detective quantum efficiency (DQE).

Cervical soft tissue imaging using a mobile CBCT scanner with a flat panel detector in comparison with corresponding CT and MRI data sets.

PubMed

Heiland, Max; Pohlenz, Philipp; Blessmann, Marco; Habermann, Christian R; Oesterhelweg, Lars; Begemann, Philipp C; Schmidgunst, Christian; Blake, Felix A S; Püschel, Klaus; Schmelzle, Rainer; Schulze, Dirk

2007-12-01

The aim of this study was to evaluate soft tissue image quality of a mobile cone-beam computed tomography (CBCT) scanner with an integrated flat-panel detector. Eight fresh human cadavers were used in this study. For evaluation of soft tissue visualization, CBCT data sets and corresponding computed tomography (CT) and magnetic resonance imaging (MRI) data sets were acquired. Evaluation was performed with the help of 10 defined cervical anatomical structures. The statistical analysis of the scoring results of 3 examiners revealed the CBCT images to be of inferior quality regarding the visualization of most of the predefined structures. Visualization without a significant difference was found regarding the demarcation of the vertebral bodies and the pyramidal cartilages, the arteriosclerosis of the carotids (compared with CT), and the laryngeal skeleton (compared with MRI). Regarding arteriosclerosis of the carotids compared with MRI, CBCT proved to be superior. The integration of a flat-panel detector improves soft tissue visualization using a mobile CBCT scanner.

Pictorial Review of Digital Radiography Artifacts.

PubMed

Walz-Flannigan, Alisa I; Brossoit, Kimberly J; Magnuson, Dayne J; Schueler, Beth A

2018-01-01

Visual familiarity with the variety of digital radiographic artifacts is needed to identify, resolve, or prevent image artifacts from creating issues with patient imaging. Because the mechanism for image creation is different between flat-panel detectors and computed radiography, the causes and appearances of some artifacts can be unique to these different modalities. Examples are provided of artifacts that were found on clinical images or during quality control testing with flat-panel detectors. The examples are meant to serve as learning tools for future identification and troubleshooting of artifacts and as a reminder for steps that can be taken for prevention. The examples of artifacts provided are classified according to their causal connection in the imaging chain, including an equipment defect as a result of an accident or mishandling, debris or gain calibration flaws, a problematic acquisition technique, signal transmission failures, and image processing issues. Specific artifacts include those that are due to flat-panel detector drops, backscatter, debris in the x-ray field during calibration, detector saturation or underexposure, or collimation detection errors, as well as a variety of artifacts that are processing induced. © RSNA, 2018.

Transmission type flat-panel X-ray source using ZnO nanowire field emitters

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

Chen, Daokun; Song, Xiaomeng; Zhang, Zhipeng

2015-12-14

A transmission type flat-panel X-ray source in diode structure was fabricated. Large-scale patterned ZnO nanowires grown on a glass substrate by thermal oxidation were utilized as field emitters, and tungsten thin film coated on silica glass was used as the transmission anode. Uniform distribution of X-ray generation was achieved, which benefited from the uniform electron emission from ZnO nanowires. Self-ballasting effect induced by the intrinsic resistance of ZnO nanowire and decreasing of screening effect caused by patterned emitters account for the uniform emission. Characteristic X-ray peaks of W-L lines and bremsstrahlung X-rays have been observed under anode voltages at amore » range of 18–20 kV, the latter of which were the dominant X-ray signals. High-resolution X-ray images with spatial resolution less than 25 μm were obtained by the flat-panel X-ray source. The high resolution was attributed to the small divergence angle of the emitted X-rays from the transmission X-ray source.« less

A swept wing panel in a low speed flexible walled test section

NASA Technical Reports Server (NTRS)

Goodyer, M. J.

1987-01-01

The testing of two-dimensional airfoil sections in adaptive wall tunnels is relatively widespread and has become routine at all speeds up to transonic. In contrast, the experience with the three-dimensional testing of swept panels in adaptive wall test sections is very limited, except for some activity in the 1940's at NPL, London. The current interest in testing swept wing panels led to the work covered by this report, which describes the design of an adaptive-wall swept-wing test section for a low speed wind tunnel and gives test results for a wing panel swept at 40 deg. The test section has rigid flat sidewalls supporting the panel, and features flexible top and bottom wall with ribs swept at the same angle as the wing. When streamlined, the walls form waves swept at the same angle as the wing. The C sub L (-) curve for the swept wing, determined from its pressure distributions taken with the walls streamlined, compare well with reference data which was taken on the same model, unswept, in a test section deep enough to avoid wall interference.

2. VIEW OF THE EXPERIMENT CONTROL PANEL IN 1970. THE ...

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

2. VIEW OF THE EXPERIMENT CONTROL PANEL IN 1970. THE NUCLEAR SAFETY GROUP CONDUCTED ABOUT 1,700 CRITICAL MASS EXPERIMENTS USING URANIUM AND PLUTONIUM IN SOLUTIONS (900 TESTS), COMPACTED POWDER (300), AND METALLIC FORMS (500). ALL 1,700 CRITICALITY ASSEMBLIES WERE CONTROLLED FROM THIS PANEL. - Rocky Flats Plant, Critical Mass Laboratory, Intersection of Central Avenue & 86 Drive, Golden, Jefferson County, CO

Phase I Contaminant Transport Parameters for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 97: Yucca Flat/Climax Mine, Nevada Test Site, Nye County, Nevada, Revision 0

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

John McCord

2007-09-01

This report documents transport data and data analyses for Yucca Flat/Climax Mine CAU 97. The purpose of the data compilation and related analyses is to provide the primary reference to support parameterization of the Yucca Flat/Climax Mine CAU transport model. Specific task objectives were as follows: • Identify and compile currently available transport parameter data and supporting information that may be relevant to the Yucca Flat/Climax Mine CAU. • Assess the level of quality of the data and associated documentation. • Analyze the data to derive expected values and estimates of the associated uncertainty and variability. The scope of thismore » document includes the compilation and assessment of data and information relevant to transport parameters for the Yucca Flat/Climax Mine CAU subsurface within the context of unclassified source-term contamination. Data types of interest include mineralogy, aqueous chemistry, matrix and effective porosity, dispersivity, matrix diffusion, matrix and fracture sorption, and colloid-facilitated transport parameters.« less

Designing, Modeling, Constructing, and Testing a Flat Panel Speaker and Sound Diffuser for a Simulator

NASA Technical Reports Server (NTRS)

Dillon, Christina

2013-01-01

The goal of this project was to design, model, build, and test a flat panel speaker and frame for a spherical dome structure being made into a simulator. The simulator will be a test bed for evaluating an immersive environment for human interfaces. This project focused on the loud speakers and a sound diffuser for the dome. The rest of the team worked on an Ambisonics 3D sound system, video projection system, and multi-direction treadmill to create the most realistic scene possible. The main programs utilized in this project, were Pro-E and COMSOL. Pro-E was used for creating detailed figures for the fabrication of a frame that held a flat panel loud speaker. The loud speaker was made from a thin sheet of Plexiglas and 4 acoustic exciters. COMSOL, a multiphysics finite analysis simulator, was used to model and evaluate all stages of the loud speaker, frame, and sound diffuser. Acoustical testing measurements were utilized to create polar plots from the working prototype which were then compared to the COMSOL simulations to select the optimal design for the dome. The final goal of the project was to install the flat panel loud speaker design in addition to a sound diffuser on to the wall of the dome. After running tests in COMSOL on various speaker configurations, including a warped Plexiglas version, the optimal speaker design included a flat piece of Plexiglas with a rounded frame to match the curvature of the dome. Eight of these loud speakers will be mounted into an inch and a half of high performance acoustic insulation, or Thinsulate, that will cover the inside of the dome. The following technical paper discusses these projects and explains the engineering processes used, knowledge gained, and the projected future goals of this project

Multiple-Panel Cylindrical Solar Concentrator

NASA Technical Reports Server (NTRS)

Brown, E. M.

1983-01-01

Trough composed of many panels concentrates Sun's energy on solar cells, even when trough is not pointed directly at Sun. Tolerates deviation as great as 5 degrees from direction of sun. For terrestrial applications, multiple-flat-plate design offers potential cost reduction and ease of fabrication.

F‐GHG Emissions Reduction Efforts: FY2015 Supplier Profiles

EPA Pesticide Factsheets

The Supplier Profiles outlined in this document detail the efforts of large‐area flat panel suppliers to reduce their F‐GHG emissions in manufacturing facilities that make today’s large‐area panels used for products such as TVs and computer monitors.

F‐GHG Emissions Reduction Efforts: FY2016 Supplier Profiles

EPA Pesticide Factsheets

The Supplier Profiles outlined in this document detail the efforts of large‐area flat panel suppliers to reduce their F‐GHG emissions in manufacturing facilities that make today’s large‐area panels used for products such as TVs and computer monitors.

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.

Cell-mediated fibre recruitment drives extracellular matrix mechanosensing in engineered fibrillar microenvironments

NASA Astrophysics Data System (ADS)

Baker, Brendon M.; Trappmann, Britta; Wang, William Y.; Sakar, Mahmut S.; Kim, Iris L.; Shenoy, Vivek B.; Burdick, Jason A.; Chen, Christopher S.

2015-12-01

To investigate how cells sense stiffness in settings structurally similar to native extracellular matrices, we designed a synthetic fibrous material with tunable mechanics and user-defined architecture. In contrast to flat hydrogel surfaces, these fibrous materials recapitulated cell-matrix interactions observed with collagen matrices including stellate cell morphologies, cell-mediated realignment of fibres, and bulk contraction of the material. Increasing the stiffness of flat hydrogel surfaces induced mesenchymal stem cell spreading and proliferation; however, increasing fibre stiffness instead suppressed spreading and proliferation for certain network architectures. Lower fibre stiffness permitted active cellular forces to recruit nearby fibres, dynamically increasing ligand density at the cell surface and promoting the formation of focal adhesions and related signalling. These studies demonstrate a departure from the well-described relationship between material stiffness and spreading established with hydrogel surfaces, and introduce fibre recruitment as a previously undescribed mechanism by which cells probe and respond to mechanics in fibrillar matrices.

Amorphous silicon thin-film transistor active-matrix for reflective cholesteric liquid crystal displays

NASA Astrophysics Data System (ADS)

Nahm, Jeong-Yeop

Reflective cholesteric liquid crystal displays (Ch-LCDs) have advantages, such as, high brightness, low power consumption, and wide viewing angle, since they do not need any polarizer, color filter, and backlight. Furthermore, due to their bistability Ch-LCDs can retain their images virtually forever without additional power consumption. But conventional passive-matrix addressing of Ch-LCDs allows only a slow image updating speed. Active-matrix addressing should allow fast image updating or video-rate operation. However, because the threshold voltage of cholesteric, liquid crystal is high (>20V), the switching devices for active-matrix addressing should satisfy required characteristics even under high bias conditions. In order to investigate the applicability of hydrogenated amorphous silicon thin film transistors (a-Si:H TFTs) for the switching devices of active-matrix (AM) Ch-LCDs, the characteristics of conventional and gate offset high voltage a-Si:H TTFs were examined under high bias conditions. And it was concluded that high OFF-current of conventional a-Si:H TFTs and low ON-current of gate offset high voltage a-Si:H TFTs were main problems for reflective AM Ch-LCD applications. In order to improve the TFT characteristics under high bias conditions, we propose two new a-Si:H TFT structures called gate planarized (GP) and buried field plate (BFP) high voltage a-Si:H TFTs. Firstly, in the GP a-Si:H TFTs, we used a thick spin-coated benzocyclobutene (BCB) layer beneath a thin hydrogenated amorphous silicon nitride (a-SiNx:H) layer for gate insulator. The GP a-Si:H TFT showed normal TFT characteristic up to VGS = VDS = ˜100 V without any device failure. But TFT ON-current of GP a-Si:H TFT was reduced due to the introduction of the thick low dielectric BCB layer. Secondly, in the BFP a-Si:H TFT, an offset region and a buried field plate were introduced between the drain/source and gate electrodes to reduce the electric field in the pinch-off region. For this BFP a-Si:H TFT, a low OFF-current (1.04 pA) and a high ON/OFF-current ratio (5.68 x 106) up to VGS = VDS = ˜30 V were obtained. Based on our a-Si:H TFTs studies, we designed an a-Si:H TFT active-matrix panel and fabricated the AM Ch-LCDs either by optimizing a-Si:H TFT processing or adopting the GP a-Si:H TFT technology. The fabricated a-Si:H TFT active-matrix panels can be operated at the voltage of 50 and 60V, applied to the data and gate lines, respectively. With the a-Si:H TFT active-matrix panels, the AM Ch-LCDs were fabricated and operated with the frame rate of 60 Hz and the maximum contrast ratio of ˜30.

16. Detail of original wainscot in the dining room. The ...

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

16. Detail of original wainscot in the dining room. The wainscot panels are flat (not beveled) and are painted along the edge to simulate a raised (beveled) panel. Credit GADA/MRM. - Stroud Building, 31-33 North Central Avenue, Phoenix, Maricopa County, AZ

Chemically amplified i-line positive resist for next-generation flat panel display

NASA Astrophysics Data System (ADS)

Lee, Hsing-Chieh; Lu, Ying-Hao; Huang, Shin-Yih; Lan, Wei-Jen; Hanabata, Makoto

2017-03-01

Traditional diazonaphthoquinone (DNQ) positive photoresists are widely used for TFT-LCD array process. Current LTPS technology has more than 600ppi resolution is required for small or middle-sized TFT liquid crystal display panels. One of the ways to enhance resolution is to apply i-line single exposure system instead of traditional g/h/ibroadband exposure system. We have been developing i-line chemically amplified photoresist ECA 200 series for the next generation flat panel display (FPD). ECA 200 consists of three components: a phenol resin, a photo acid generator and dissolution enhancer. We applied two different types of dissolution enhancers with two different kinds of protected groups to our resist materials. As a result, we achieved higher sensitivity, higher resolution, less footing of the resist profile and reduced standing wave effect compared with traditional DNQ photoresists. In addition, we have found further property of photoresist that does not need post exposure bake (PEB) process. This resist has a great advantage at most of current panel plants without PEB process.

Effect of boundary conditions and panel geometry on the response of laminated panels subjected to transverse pressure loads

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.

1993-01-01

The behavior of thin laminated flat and curved panels subjected to transverse pressure and inplane loads is considered. The effects of panel geometry, boundary conditions and laminate stacking sequence on the response of panels subjected to transverse pressure loads up to 12.4 N/sq cm is presented. The response of thin laminated panels is evaluated analytically and selected results are compared with test data. A parametric study of the deformation and strain responses of panels with radius of curvature ranging from 20 to 305 cm is presented. The combination of inplane tensile and pressure loads is also considered.

Evaluation of viewing experiences induced by a curved three-dimensional display

NASA Astrophysics Data System (ADS)

Mun, Sungchul; Park, Min-Chul; Yano, Sumio

2015-10-01

Despite an increased need for three-dimensional (3-D) functionality in curved displays, comparisons pertinent to human factors between curved and flat panel 3-D displays have rarely been tested. This study compared stereoscopic 3-D viewing experiences induced by a curved display with those of a flat panel display by evaluating subjective and objective measures. Twenty-four participants took part in the experiments and viewed 3-D content with two different displays (flat and curved 3-D display) within a counterbalanced and within-subject design. For the 30-min viewing condition, a paired t-test showed significantly reduced P300 amplitudes, which were caused by engagement rather than cognitive fatigue, in the curved 3-D viewing condition compared to the flat 3-D viewing condition at P3 and P4. No significant differences in P300 amplitudes were observed for 60-min viewing. Subjective ratings of realness and engagement were also significantly higher in the curved 3-D viewing condition than in the flat 3-D viewing condition for 30-min viewing. Our findings support that curved 3-D displays can be effective for enhancing engagement among viewers based on specific viewing times and environments.

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.

Design, development, manufacture, testing, and delivery of devices for connection of solar cell panel circuitry to flat conductor cable solar cell array harness

NASA Technical Reports Server (NTRS)

Dillard, P. A.; Waddington, D.

1971-01-01

The technology status and problem areas which exist for the application of flat conductor cabling to solar cell arrays are summarized. Details covering the design, connector manufacture, and prototype test results are also summarized.

Simultaneous Detection of Metalloprotease Activities in Complex Biological Samples Using the PrAMA (Proteolytic Activity Matrix Assay) Method.

PubMed

Conrad, Catharina; Miller, Miles A; Bartsch, Jörg W; Schlomann, Uwe; Lauffenburger, Douglas A

2017-01-01

Proteolytic Activity Matrix Analysis (PrAMA) is a method for simultaneously determining the activities of specific Matrix Metalloproteinases (MMPs) and A Disintegrin and Metalloproteinases (ADAMs) in complex biological samples. In mixtures of unknown proteases, PrAMA infers selective metalloproteinase activities by using a panel of moderately specific FRET-based polypeptide protease substrates in parallel, typically monitored by a plate-reader in a 96-well format. Fluorescence measurements are then quantitatively compared to a standard table of catalytic efficiencies measured from purified mixtures of individual metalloproteinases and FRET substrates. Computational inference of specific activities is performed with an easily used Matlab program, which is provided herein. Thus, we describe PrAMA as a combined experimental and mathematical approach to determine real-time metalloproteinase activities, which has previously been applied to live-cell cultures, cellular lysates, cell culture supernatants, and body fluids from patients.

Structural parameters that influence the noise reduction characteristics of typical general aviation materials

NASA Technical Reports Server (NTRS)

Roskam, J.; Grosveld, F.

1980-01-01

Effect of panel curvature and oblique angle of sound incidence on noise reduction characteristics of an aluminum panel are experimentally investigated. Panel curvature results show significant increase in stiffness with comparable decrease of sound transmission through the panel in the frequency region below the panel/cavity resonance frequency. Noise reduction data have been achieved for aluminum panels with clamped, bonded and riveted edge conditions. These edge conditions are shown to influence noise reduction characteristics of aluminum panels. Experimentally measured noise reduction characteristics of flat aluminum panels with uniaxial and biaxial in-plane stresses are presented and discussed. Results indicate important improvement in noise reduction of these panels in the frequency range below the fundamental panel/cavity resonance frequency.

Extra-oral dental radiography for disaster victims using a flat panel X-ray detector and a hand-held X-ray generator.

PubMed

Ohtani, M; Oshima, T; Mimasaka, S

2017-12-01

Forensic odontologists commonly incise the skin for post-mortem dental examinations when it is difficult to open the victim's mouth. However, it is prohibited by law to incise dead bodies without permission in Japan. Therefore, we attempted using extra-oral dental radiography, using a digital X-ray equipment with rechargeable batteries, to overcome this restriction. A phantom was placed in the prone position on a table, and three plain dental radiographs were used per case: "lateral oblique radiographs" for left and right posterior teeth and a "contact radiograph" for anterior teeth were taken using a flat panel X-ray detector and a hand-held X-ray generator. The resolving power of the images was measured by a resolution test chart, and the scattered X-ray dose was measured using an ionization chamber-type survey meter. The resolving power of the flat panel X-ray detector was 3.0 lp/mm, which was less than that of intra-oral dental methods, but the three extra-oral plain dental radiographs provided the overall dental information from outside of the mouth, and this approach was less time-consuming. In addition, the higher dose of scattered X-rays was laterally distributed, but the dose per case was much less than that of intra-oral dental radiographs. Extra-oral plain dental radiography can be used for disaster victim identification by dental methods even when it is difficult to open the mouth. Portable and rechargeable devices, such as a flat panel X-ray detector and a hand-held X-ray generator, are convenient to bring and use anywhere, even at a disaster scene lacking electricity and water.

Portal imaging with flat-panel detector and CCD camera

NASA Astrophysics Data System (ADS)

Roehrig, Hans; Tang, Chuankun; Cheng, Chee-Wai; Dallas, William J.

1997-07-01

This paper provides a comparison of imaging parameters of two portal imaging systems at 6 MV: a flat panel detector and a CCD-camera based portal imaging system. Measurements were made of the signal and noise and consequently of signal-to-noise per pixel as a function of the exposure. Both systems have a linear response with respect to exposure, and the noise is proportional to the square-root of the exposure, indicating photon-noise limitation. The flat-panel detector has a signal- to-noise ratio, which is higher than that observed wit the CCD-camera based portal imaging system. This is expected because most portal imaging systems using optical coupling with a lens exhibit severe quantum-sinks. The paper also presents data on the screen's photon gain (the number of light-photons per interacting x-ray photon), as well as on the magnitude of the Swank-noise, (which describes fluctuation in the screen's photon gain). Images of a Las Vegas-type aluminum contrast detail phantom, located at the ISO-Center, were generated at an exposure of 1 MU. The CCD-camera based system permits detection of aluminum-holes of 0.01194 cm diameter and 0.228 mm depth while the flat-panel detector permits detection of aluminum holes of 0.01194 cm diameter and 0.1626 mm depth, indicating a better signal-to-noise ratio. Rank order filtering was applied to the raw images from the CCD-based system in order to remove the direct hits. These are camera responses to scattered x-ray photons which interact directly with the CCD of the CCD-camera and generate 'salt and pepper type noise,' which interferes severely with attempts to determine accurate estimates of the image noise.

Effect of monitor display on detection of approximal caries lesions in digital radiographs.

PubMed

Isidor, S; Faaborg-Andersen, M; Hintze, H; Kirkevang, L-L; Frydenberg, M; Haiter-Neto, F; Wenzel, A

2009-12-01

The aim was to compare the accuracy of five flat panel monitors for detection of approximal caries lesions. Five flat panel monitors, Mermaid Ventura (15 inch, colour flat panel, 1024 x 768, 32 bit, analogue), Olórin VistaLine (19 inch, colour, 1280 x 1024, 32 bit, digital), Samsung SyncMaster 203B (20 inch, colour, 1024 x 768, 32 bit, analogue), Totoku ME251i (21 inch, greyscale, 1400 x 1024, 32 bit, digital) and Eizo FlexScan MX190 (19 inch, colour, 1280 x 1024, 32 bit, digital), were assessed. 160 approximal surfaces of human teeth were examined with a storage phosphor plate system (Digora FMX, Soredex) and assessed by seven observers for the presence of caries lesions. Microscopy of the teeth served as validation for the presence/absence of a lesion. The sensitivities varied between observers (range 7-25%) but the variation between the monitors was not large. The Samsung monitor obtained a significantly higher sensitivity than the Mermaid and Olórin monitors (P<0.02) and a lower specificity than the Eizo and Totoku monitors (P<0.05). There were no significant differences between any other monitors. The percentage of correct scores was highest for the Eizo monitor and significantly higher than for the Mermaid and Olórin monitors (P<0.03). There was no clear relationship between the diagnostic accuracy and the resolution or price of the monitor. The Eizo monitor was associated with the overall highest percentage of correct scores. The standard analogue flat panel monitor, Samsung, had higher sensitivity and lower specificity than some of the other monitors, but did not differ in overall accuracy for detection of carious lesions.

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.

Test and Analysis of Foam Impacting a 6x6 Inch RCC Flat Panel

NASA Technical Reports Server (NTRS)

Lessard, Wendy B.

2006-01-01

This report presents the testing and analyses of a foam projectile impacting onto thirteen 6x6 inch flat panels at a 90 degrees incidence angle. The panels tested in this investigation were fabricated of Reinforced-Carbon-Carbon material and were used to aid in the validation of an existing material model, MAT58. The computational analyses were performed using LS-DYNA, which is a physics-based, nonlinear, transient, finite element code used for analyzing material responses subjected to high impact forces and other dynamic conditions. The test results were used to validate LS-DYNA predictions and to determine the threshold of damage generated by the MAT58 cumulative damage material model. The threshold of damage parameter represents any external or internal visible RCC damage detectable by nondestructive evaluation techniques.

Acousto-ultrasonic decay in metal matrix composite panels

NASA Technical Reports Server (NTRS)

Kautz, Harold E.

1995-01-01

Acousto-ultrasonic (A-U) decay rates (UD) were measured in metal matrix composite (MMC) panels. The MMC panels had fiber architectures and cross-sectional thicknesses corresponding to those designed for aerospace turbine engine structures. The wavelength-to-thickness ratio produced by the combination of experimental frequency setting conditions and specimen geometry was found to be a key parameter for identifying optimum conditions for UD measurements. The ratio was shown to be a useful rule of thumb when applied to ceramic matrix composites (CMC)s and monolithic thermo-plastics.

High resolution micro-CT of low attenuating organic materials using large area photon-counting detector

NASA Astrophysics Data System (ADS)

Kumpová, I.; Vavřík, D.; Fíla, T.; Koudelka, P.; Jandejsek, I.; Jakůbek, J.; Kytýř, D.; Zlámal, P.; Vopálenský, M.; Gantar, A.

2016-02-01

To overcome certain limitations of contemporary materials used for bone tissue engineering, such as inflammatory response after implantation, a whole new class of materials based on polysaccharide compounds is being developed. Here, nanoparticulate bioactive glass reinforced gelan-gum (GG-BAG) has recently been proposed for the production of bone scaffolds. This material offers promising biocompatibility properties, including bioactivity and biodegradability, with the possibility of producing scaffolds with directly controlled microgeometry. However, to utilize such a scaffold with application-optimized properties, large sets of complex numerical simulations using the real microgeometry of the material have to be carried out during the development process. Because the GG-BAG is a material with intrinsically very low attenuation to X-rays, its radiographical imaging, including tomographical scanning and reconstructions, with resolution required by numerical simulations might be a very challenging task. In this paper, we present a study on X-ray imaging of GG-BAG samples. High-resolution volumetric images of investigated specimens were generated on the basis of micro-CT measurements using a large area flat-panel detector and a large area photon-counting detector. The photon-counting detector was composed of a 010× 1 matrix of Timepix edgeless silicon pixelated detectors with tiling based on overlaying rows (i.e. assembled so that no gap is present between individual rows of detectors). We compare the results from both detectors with the scanning electron microscopy on selected slices in transversal plane. It has been shown that the photon counting detector can provide approx. 3× better resolution of the details in low-attenuating materials than the integrating flat panel detectors. We demonstrate that employment of a large area photon counting detector is a good choice for imaging of low attenuating materials with the resolution sufficient for numerical simulations.

Flat band in disorder-driven non-Hermitian Weyl semimetals

NASA Astrophysics Data System (ADS)

Zyuzin, A. A.; Zyuzin, A. Yu.

2018-01-01

We study the interplay of disorder and band-structure topology in a Weyl semimetal with a tilted conical spectrum around the Weyl points. The spectrum of particles is given by the eigenvalues of a non-Hermitian matrix, which contains contributions from a Weyl Hamiltonian and complex self-energy due to electron elastic scattering on disorder. We find that the tilt-induced matrix structure of the self-energy gives rise to either a flat band or a nodal line segment at the interface of the electron and hole pockets in the bulk band structure of type-II Weyl semimetals depending on the Weyl cone inclination. For the tilt in a single direction in momentum space, each Weyl point expands into a flat band lying on the plane, which is transverse to the direction of the tilt. The spectrum of the flat band is fully imaginary and is separated from the in-plane dispersive part of the spectrum by the "exceptional nodal ring" where the matrix of the Green's function in momentum-frequency space is defective. The tilt in two directions might shrink a flat band into a nodal line segment with "exceptional edge points." We discuss the connection to the non-Hermitian topological theory.

Thermostructural Properties Of Sic/Sic Panels With 2.5d And 3d Fiber Architectures

NASA Technical Reports Server (NTRS)

Yun, H. M.; DeCarlo, J. A.; Bhatt, R. H.; Jaskowiak, M. H.

2005-01-01

CMC hot-section components in advanced engines for power and propulsion will typically require high cracking strength, high ultimate strength and strain, high creep- rupture resistance, and high thermal conductivity in all directions. In the past, NASA has demonstrated fabrication of a variety of SiC/SiC flat panels and round tubes with various 2D fiber architectures using the high-modulus high-performance Sylramic-iBN Sic fiber and Sic-based matrices derived by CVI, MI, and/or PIP processes. The thermo- mechanical properties of these CMC have shown state-of-the-art performance, but primarily in the in-plane directions. Currently NASA is extending the thermostructural capability of these SiC/SiC systems in the thru-thickness direction by using various 2.5D and 3D fiber architectures. NASA is also using specially designed fabrication steps to optimize the properties of the BN-based interphase and Sic-based matrices. In this study, Sylramic-iBN/SiC panels with 2D plain weave, 2.5D satin weave, 2.5D ply-to-ply interlock weave, and 3D angle interlock fiber architectures, all woven at AITI, were fabricated using matrix densification routes previously established between NASA and GEPSC for CVI-MI processes and between NASA and Starfire-Systems for PIP processes. Introduction of the 2.5 D fiber architecture along with an improved matrix process was found to increase inter-laminar tensile strength from 1.5 -2 to 3 - 4 ksi and thru-thickness thermal conductivity from 15-20 to 30-35 BTU/ft.hr.F with minimal reduction in in-plane strength and creep-rupture properties. Such improvements should reduce thermal stresses and increase the thermostructural operating envelope for SiC/SiC engine components. These results are analyzed to offer general guidelines for selecting fiber architectures and constituent processes for high-performance SiC/SiC engine components.

Percutaneous foot joint needle placement using a C-arm flat-panel detector CT.

PubMed

Wiewiorski, Martin; Takes, Martin Thanh Long; Valderrabano, Victor; Jacob, Augustinus Ludwig

2012-03-01

Image guidance is valuable for diagnostic injections in foot orthopaedics. Flat-detector computed tomography (FD-CT) was implemented using a C-arm, and the system was tested for needle guidance in foot joint injections. FD-CT-guided joint infiltration was performed in 6 patients referred from the orthopaedic department for diagnostic foot injections. All interventions were performed utilising a flat-panel fluoroscopy system utilising specialised image guidance and planning software. Successful infiltration was defined by localisation of contrast media depot in the targeted joint. The pre- and post-interventional numeric analogue scale (NAS) pain score was assessed. All injections were technically successful. Contrast media deposit was documented in all targeted joints. Significant relief of symptoms was noted by all 6 participants. FD-CT-guided joint infiltration is a feasible method for diagnostic infiltration of midfoot and hindfoot joints. The FD-CT approach may become an alternative to commonly used 2D-fluoroscopically guidance.

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.

Study of noise reduction characteristics of multilayered panels and dual pane windows with Helmholtz resonators

NASA Technical Reports Server (NTRS)

Navaneethan, R.

1981-01-01

The experimental noise attenuation characteristics of flat, general aviation type, multilayered panels are discussed. Experimental results of stiffened panels, damping tape, honeycomb materials and sound absorption materials are presented. Single degree of freedom theoretical models were developed for sandwich type panels with both shear resistant and non-shear resistant core material. The concept of Helmholtz resonators used in conjunction with dual panel windows in increasing the noise reduction around a small range of frequency was tested. It is concluded that the stiffening of the panels either by stiffeners or by sandwich construction increases the low frequency noise reduction.

Tow-Steered Panels With Holes Subjected to Compression or Shear Loads

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.; Tatting, Brian F.; Guerdal, Zafer

2005-01-01

Tailoring composite laminates to vary the fiber orientations within a fiber layer of a laminate to address non-uniform stress states and provide structural advantages such as the alteration of principal load paths has potential application to future low-cost, light-weight structures for commercial transport aircraft. Evaluation of this approach requires the determination of the effectiveness of stiffness tailoring through the use of curvilinear fiber paths in flat panels including the reduction of stress concentrations around the holes and the increase in load carrying capability. Panels were designed through the use of an optimization code using a genetic algorithm and fabricated using a tow-steering approach. Manufacturing limitations, such as the radius of curvature of tows the machine could support, avoidance of wrinkling of fibers and minimization of gaps between fibers were considered in the design process. Variable stiffness tow-steered panels constructed with curvilinear fiber paths were fabricated so that the design methodology could be verified through experimentation. Finite element analysis where each element s stacking sequence was accurately defined is used to verify the behavior predicted based on the design code. Experiments on variable stiffness flat panels with central circular holes were conducted with the panels loaded in axial compression or shear. Tape and tow-steered panels are used to demonstrate the buckling, post-buckling and failure behavior of elastically tailored panels. The experimental results presented establish the buckling performance improvements attainable by elastic tailoring of composite laminates.

Scaling the Non-linear Impact Response of Flat and Curved Composite Panels

NASA Technical Reports Server (NTRS)

Ambur, Damodar R.; Chunchu, Prasad B.; Rose, Cheryl A.; Feraboli, Paolo; Jackson, Wade C.

2005-01-01

The application of scaling laws to thin flat and curved composite panels exhibiting nonlinear response when subjected to low-velocity transverse impact is investigated. Previous research has shown that the elastic impact response of structural configurations exhibiting geometrically linear response can be effectively scaled. In the present paper, a preliminary experimental study is presented to assess the applicability of the scaling laws to structural configurations exhibiting geometrically nonlinear deformations. The effect of damage on the scalability of the structural response characteristics, and the effect of scale on damage development are also investigated. Damage is evaluated using conventional methods including C-scan, specimen de-plying and visual inspection of the impacted panels. Coefficient of restitution and normalized contact duration are also used to assess the extent of damage. The results confirm the validity of the scaling parameters for elastic impacts. However, for the panels considered in the study, the extent and manifestation of damage do not scale according to the scaling laws. Furthermore, the results indicate that even though the damage does not scale, the overall panel response characteristics, as indicated by contact force profiles, do scale for some levels of damage.

Solving bezel reliability and CRT obsolescence

NASA Astrophysics Data System (ADS)

Schwartz, Richard J.; Bowen, Arlen R.; Knowles, Terry

2003-09-01

Scientific Research Corporation designed a Smart Multi-Function Color Display with Positive Pilot Feedback under the funding of an U. S. Navy Small Business Innovative Research program. The Smart Multi-Function Color Display can replace the obsolete monochrome Cathode Ray Tube display currently on the T-45C aircraft built by Boeing. The design utilizes a flat panel color Active Matrix Liquid Crystal Display and TexZec's patented Touch Thru Metal bezel technology providing both visual and biomechanical feedback to the pilot in a form, fit, and function replacement to the current T-45C display. Use of an existing color AMLCD, requires the least adaptation to fill the requirements of this application, thereby minimizing risk associated with developing a new display technology and maximizing the investment in improved user interface technology. The improved user interface uses TexZec's Touch Thru Metal technology to eliminate all of the moving parts that traditionally have limited Mean-Time-Between-Failure. The touch detection circuit consists of Commercial-Off-The-Shelf components, creating touch detection circuitry, which is simple and durable. This technology provides robust switch activation and a high level of environmental immunity, both mechanical and electrical. Replacement of all the T-45C multi-function displays with this design will improve the Mean-Time-Between-Failure and drastically reduce display life cycle costs. The design methodology described in this paper can be adapted to any new or replacement display.

In vitro growth of flat aragonite crystals between the layers of the insoluble organic matrix of the abalone Haliotis laevigata

NASA Astrophysics Data System (ADS)

Gries, Katharina I.; Heinemann, Fabian; Rosenauer, Andreas; Fritz, Monika

2012-11-01

Nacre of abalone shells consists of aragonite platelets and organic material, the so-called organic matrix. During the growth process of the shell the aragonite platelets grow into a scaffold formed by the organic matrix. In this work we tried to mimic this growth process by placing a piece of the insoluble organic matrix (which is a part of the organic matrix) of the abalone Haliotis laevigata in a crystallization device which was flowed through by CaCl2 and NaHCO3 solutions. Using this setup amongst others flat aragonite crystals grow on the insoluble organic matrix. When investigating these crystals in a transmission electron microscope it is possible to recognize similarities to the structure of nacre, like the formation of mineral bridges and growth between layers of the insoluble organic matrix. These similarities are presented in this paper.

A compact high resolution flat panel PET detector based on the new 4-side buttable MPPC for biomedical applications.

PubMed

Wang, Qiang; Wen, Jie; Ravindranath, Bosky; O'Sullivan, Andrew W; Catherall, David; Li, Ke; Wei, Shouyi; Komarov, Sergey; Tai, Yuan-Chuan

2015-09-11

Compact high-resolution panel detectors using virtual pinhole (VP) PET geometry can be inserted into existing clinical or pre-clinical PET systems to improve regional spatial resolution and sensitivity. Here we describe a compact panel PET detector built using the new Though Silicon Via (TSV) multi-pixel photon counters (MPPC) detector. This insert provides high spatial resolution and good timing performance for multiple bio-medical applications. Because the TSV MPPC design eliminates wire bonding and has a package dimension which is very close to the MPPC's active area, it is 4-side buttable. The custom designed MPPC array (based on Hamamatsu S12641-PA-50(x)) used in the prototype is composed of 4 × 4 TSV-MPPC cells with a 4.46 mm pitch in both directions. The detector module has 16 × 16 lutetium yttrium oxyorthosilicate (LYSO) crystal array, with each crystal measuring 0.92 × 0.92 × 3 mm 3 with 1.0 mm pitch. The outer diameter of the detector block is 16.8 × 16.8 mm 2 . Thirty-two such blocks will be arranged in a 4 × 8 array with 1 mm gaps to form a panel detector with detection area around 7 cm × 14 cm in the full-size detector. The flood histogram acquired with Ge-68 source showed excellent crystal separation capability with all 256 crystals clearly resolved. The detector module's mean, standard deviation, minimum (best) and maximum (worst) energy resolution were 10.19%, +/-0.68%, 8.36% and 13.45% FWHM, respectively. The measured coincidence time resolution between the block detector and a fast reference detector (around 200 ps single photon timing resolution) was 0.95 ns. When tested with Siemens Cardinal electronics the performance of the detector blocks remain consistent. These results demonstrate that the TSV-MPPC is a promising photon sensor for use in a flat panel PET insert composed of many high resolution compact detector modules.

Imperfection and Thickness Measurement of Panels Using a Coordinate Measurement Machine

NASA Technical Reports Server (NTRS)

Thornburgh, Robert P.

2006-01-01

This paper summarizes the methodology used to measure imperfection and thickness variation for flat and curved panels using a Coordinate Measurement Machine (CMM) and the software program MeasPanel. The objective is to provide a reference document so that someone with a basic understanding of CMM operation can measure a panel with minimal training. Detailed information about both the measurement system setup and computer software is provided. Information is also provided about the format of the raw data, as well as how it is post-processed for use in finite-element analysis.

19. VIEW OF THE PLATING BATHS AND CONTROL PANELS. GOLD ...

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

19. VIEW OF THE PLATING BATHS AND CONTROL PANELS. GOLD AND SILVER WERE AMONG THE MATERIALS PLATED ONTO PARTS MADE OF COPPER, STAINLESS STEEL AND STEEL. (11/15/89) - Rocky Flats Plant, Non-Nuclear Production Facility, South of Cottonwood Avenue, west of Seventh Avenue & east of Building 460, Golden, Jefferson County, CO

Comparison of Wood Composite Properties Using Cantilever-Beam Bending

Treesearch

Houjiang Zhang; John F. Hunt; Lujing Zhou

2015-01-01

Wood-based composite panels generally are first tested out-of-plane in the primarypanel directionfollowed by the cross panel direction, but rarely edgewise. While most applications use wood-based composites in the flat-wise orientation and only need the out-of-plane properties, there are construction configurations where edgewise properties are needed for improved...

Evaluation of damping loss factor of flat laminates by sound transmission

NASA Astrophysics Data System (ADS)

Parrinello, A.; Ghiringhelli, G. L.

2018-06-01

A novel approach to investigate and evaluate the damping loss factor of a planar multilayered structure is presented. A statistical analysis reveals the connection between the damping properties of the structure and the transmission of sound through the thickness of its laterally infinite counterpart. The obtained expression for the panel loss factor involves all the derivatives of the transmission and reflection coefficients of the layered structure with respect each layer damping. The properties of the fluid for which the sound transmission is evaluated are chosen to fulfil the hypotheses on the basis of the statistical formulation. A transfer matrix approach is used to compute the required transmission and reflection coefficients, making it possible to deal with structures having arbitrary stratifications of different layers and also granting high efficiency in a wide frequency range. Comparison with alternative formulations and measurements demonstrates the effectiveness of the proposed methodology.

The Features of Self-Assembling Organic Bilayers Important to the Formation of Anisotropic Inorganic Materials in Microgravity Conditions

NASA Technical Reports Server (NTRS)

Talham, Daniel R.; Adair, James H.

1999-01-01

There is a growing need for inorganic anisotropic particles in a variety of materials science applications. Structural, optical, and electrical properties can be greatly augmented by the fabrication of composite materials with anisotropic microstructures or with anisotropic particles uniformly dispersed in an isotropic matrix. Examples include structural composites, magnetic and optical recording media, photographic film, certain metal and ceramic alloys, and display technologies including flat panel displays. While considerable progress has been made toward developing an understanding of the synthesis of powders composed of monodispersed, spherical particles, these efforts have not been transferred to the synthesis of anisotropic nanoparticles. The major objective of the program is to develop a fundamental understanding of the growth of anisotropic particles at organic templates, with emphasis on the chemical and structural aspects of layered organic assemblies that contribute to the formation of anisotropic inorganic particles.

Recent results concerning the stability of viscoelastic shear deformable plates under compressive edge loading

NASA Technical Reports Server (NTRS)

Librescu, L.; Chandiramani, N. K.

1989-01-01

Some recent results obtained by the authors are summarized concerning the stability of transversely isotropic flat panels whose materials exhibit a viscoelastic behavior and whose edges are subjected to in-plane biaxial compressive loads. Two transversely isotropic type materials, largely used in advanced technology, are considered: (1) the pyrolytic-graphite type, used in the thermal protection of aerospace vehicles, and (2) the type corresponding to unidirectional fiber-reinforced composites. In the former case, the planes of isotropy are parallel at each point to the midplane of the plate. In the latter case, they are normal to the fiber directions. The micromechanical relations developed by Aboudi (1984, 1986, 1987) are considered in conjunction with the correspondence principle of linear viscoelastic theory in order to predict the macroscopic viscoelastic properties of a material composed of uniaxial elastic fibers embedded in a linear viscoelastic matrix.

Active origami by 4D printing

NASA Astrophysics Data System (ADS)

Ge, Qi; Dunn, Conner K.; Qi, H. Jerry; Dunn, Martin L.

2014-09-01

Recent advances in three dimensional (3D) printing technology that allow multiple materials to be printed within each layer enable the creation of materials and components with precisely controlled heterogeneous microstructures. In addition, active materials, such as shape memory polymers, can be printed to create an active microstructure within a solid. These active materials can subsequently be activated in a controlled manner to change the shape or configuration of the solid in response to an environmental stimulus. This has been termed 4D printing, with the 4th dimension being the time-dependent shape change after the printing. In this paper, we advance the 4D printing concept to the design and fabrication of active origami, where a flat sheet automatically folds into a complicated 3D component. Here we print active composites with shape memory polymer fibers precisely printed in an elastomeric matrix and use them as intelligent active hinges to enable origami folding patterns. We develop a theoretical model to provide guidance in selecting design parameters such as fiber dimensions, hinge length, and programming strains and temperature. Using the model, we design and fabricate several active origami components that assemble from flat polymer sheets, including a box, a pyramid, and two origami airplanes. In addition, we directly print a 3D box with active composite hinges and program it to assume a temporary flat shape that subsequently recovers to the 3D box shape on demand.

Volumetric soft tissue brain imaging on xCAT, a mobile flat-panel x-ray CT system

NASA Astrophysics Data System (ADS)

Zbijewski, Wojciech; Stayman, J. Webster

2009-02-01

We discuss the ongoing development of soft-tissue imaging capabilities on xCAT, a highly portable, flat-panel based cone-beam X-ray CT platform. By providing the ability to rapidly detect intra-cranial bleeds and other symptoms of stroke directly at the patient's bedside, our new system can potentially significantly improve the management of neurological emergency and intensive care patients. The paper reports on the design of our system, as well as on the methods used to combat artifacts due to scatter, non-linear detector response and scintillator glare. Images of cadaveric head samples are also presented and compared with conventional CT scans.

Transparent Solar Concentrator for Flat Panel Display

NASA Astrophysics Data System (ADS)

Yeh, Chia-Hung; Chang, Fuh-Yu; Young, Hong-Tsu; Hsieh, Tsung-Yen; Chang, Chia-Hsiung

2012-06-01

A new concept of the transparent solar concentrator for flat panel display is experimentally demonstrated without adversely affecting the visual effects. The solar concentrator is based on a solar light-guide plate with micro prisms, not only increasing the absorption area of solar energy but also enhancing the conversion efficiency. The incident light is guided by the designed solar light-guide plate according to the total internal reflection (TIR), and converted into electrical power by photovoltaic solar cells. The designed transparent solar concentrator was made and measured with high transparency, namely 94.8%. The developed solar energy system for display can store energy and supply the bias voltage to light on two light-emitting diodes (LEDs) successfully.

Development of a real-time digital radiography system using a scintillator-type flat-panel detector

NASA Astrophysics Data System (ADS)

Ikeda, Shigeyuki; Suzuki, Katsumi; Ishikawa, Ken; Okajima, Kenichi

2001-06-01

In order to study the advantage and remaining problems of FPD (flat panel detector) for clinical use by the real-time DR (digital radiography) system, we developed a prototype system using a scintillator type FPD and which was compared with previous I.I.-CCD type real-time DR. We replaced the X- ray detector of DR-2000X from I.I.-4M (4 million pixels)-CCD camera to the scintillator type dynamic FPD(7' X 9', 127 micrometers ), which can take both radiographic and fluoroscopic images. We obtained the images of head and stomach phantoms, and discussed about the image quality with medical doctors.

General aviation aircraft interior noise problem: Some suggested solutions

NASA Technical Reports Server (NTRS)

Roskam, J.; Navaneethan, R.

1984-01-01

Laboratory investigation of sound transmission through panels and the use of modern data analysis techniques applied to actual aircraft is used to determine methods to reduce general aviation interior noise. The experimental noise reduction characteristics of stiffened flat and curved panels with damping treatment are discussed. The experimental results of double-wall panels used in the general aviation industry are given. The effects of skin panel material, fiberglass insulation and trim panel material on the noise reduction characteristics of double-wall panels are investigated. With few modifications, the classical sound transmission theory can be used to design the interior noise control treatment of aircraft. Acoustic intensity and analysis procedures are included.

Pentacene-based organic thin film transistors, integrated circuits, and active matrix displays on polymeric substrates

NASA Astrophysics Data System (ADS)

Sheraw, Christopher Duncan

2003-10-01

Organic thin film transistors are attractive candidates for a variety of low cost, large area commercial electronics including smart cards, RF identification tags, and flat panel displays. Of particular interest are high performance organic thin film transistors (TFTs) that can be fabricated on flexible polymeric substrates allowing low-cost, lightweight, rugged electronics such as flexible active matrix displays. This thesis reports pentacene organic thin film transistors fabricated on flexible polymeric substrates with record performance, the fastest photolithographically patterned organic TFT integrated circuits on polymeric substrates reported to date, and the fabrication of the organic TFT backplanes used to build the first organic TFT-driven active matrix liquid crystal display (AMLCD), also the first AMLCD on a flexible substrate, ever reported. In addition, the first investigation of functionalized pentacene derivatives used as the active layer in organic thin film transistors is reported. A low temperature (<110°C) process technology was developed allowing the fabrication of high performance organic TFTs, integrated circuits, and large TFT arrays on flexible polymeric substrates. This process includes the development of a novel water-based photolithographic active layer patterning process using polyvinyl alcohol that allows the patterning of organic semiconductor materials for elimination of active layer leakage current without causing device degradation. The small molecule aromatic hydrocarbon pentacene was used as the active layer material to fabricate organic TFTs on the polymeric material polyethylene naphthalate with field-effect mobility as large as 2.1 cm2/V-s and on/off current ratio of 108. These are the best values reported for organic TFTs on polymeric substrates and comparable to organic TFTs on rigid substrates. Analog and digital integrated circuits were also fabricated on polymeric substrates using pentacene TFTs with propagation delay as low as 38 musec and clocked digital circuits that operated at 1.1 kHz. These are the fastest photolithographically patterned organic TFT circuits on polymeric substrates reported to date. Finally, 16 x 16 pentacene TFT pixel arrays were fabricated on polymeric substrates and integrated with polymer dispersed liquid crystal to build an AMLCD. The pixel arrays showed good optical response to changing data signals when standard quarter-VGA display waveforms were applied. This result marks the first organic TFT-driven active matrix liquid crystal display ever reported as well as the first active matrix liquid crystal display on a flexible polymeric substrate. Lastly, functionalized pentacene derivatives were used as the active layer in organic thin film transistor materials. Functional groups were added to the pentacene molecule to influence the molecular ordering so that the amount of pi-orbital overlap would be increased allowing the potential for improved field-effect mobility. The functionalization of these materials also improves solubility allowing for the possibility of solution-processed devices and increased oxidative stability. Organic thin film transistors were fabricated using five different functionalized pentacene active layers. Devices based on the pentacene derivative triisopropylsilyl pentacene were found to have the best performance with field-effect mobility as large as 0.4 cm 2/V-s.

AAPM/RSNA physics tutorial for residents: physics of flat-panel fluoroscopy systems: Survey of modern fluoroscopy imaging: flat-panel detectors versus image intensifiers and more.

PubMed

Nickoloff, Edward Lee

2011-01-01

This article reviews the design and operation of both flat-panel detector (FPD) and image intensifier fluoroscopy systems. The different components of each imaging chain and their functions are explained and compared. FPD systems have multiple advantages such as a smaller size, extended dynamic range, no spatial distortion, and greater stability. However, FPD systems typically have the same spatial resolution for all fields of view (FOVs) and are prone to ghosting. Image intensifier systems have better spatial resolution with the use of smaller FOVs (magnification modes) and tend to be less expensive. However, the spatial resolution of image intensifier systems is limited by the television system to which they are coupled. Moreover, image intensifier systems are degraded by glare, vignetting, spatial distortions, and defocusing effects. FPD systems do not have these problems. Some recent innovations to fluoroscopy systems include automated filtration, pulsed fluoroscopy, automatic positioning, dose-area product meters, and improved automatic dose rate control programs. Operator-selectable features may affect both the patient radiation dose and image quality; these selectable features include dose level setting, the FOV employed, fluoroscopic pulse rates, geometric factors, display software settings, and methods to reduce the imaging time. © RSNA, 2011.

Metallic artifacts from internal scaphoid fracture fixation screws: comparison between C-arm flat-panel, cone-beam, and multidetector computed tomography.

PubMed

Finkenstaedt, Tim; Morsbach, Fabian; Calcagni, Maurizio; Vich, Magdalena; Pfirrmann, Christian W A; Alkadhi, Hatem; Runge, Val M; Andreisek, Gustav; Guggenberger, Roman

2014-08-01

The aim of this study was to compare image quality and extent of artifacts from scaphoid fracture fixation screws using different computed tomography (CT) modalities and radiation dose protocols. Imaging of 6 cadaveric wrists with artificial scaphoid fractures and different fixation screws was performed in 2 screw positions (45° and 90° orientation in relation to the x/y-axis) using multidetector CT (MDCT) and 2 flat-panel CT modalities, C-arm flat-panel CT (FPCT) and cone-beam CT (CBCT), the latter 2 with low and standard radiation dose protocols. Mean cartilage attenuation and metal artifact-induced absolute Hounsfield unit changes (= artifact extent) were measured. Two independent radiologists evaluated different image quality criteria using a 5-point Likert-scale. Interreader agreements (Cohen κ) were calculated. Mean absolute Hounsfield unit changes and quality ratings were compared using Friedman and Wilcoxon signed-rank tests. Artifact extent was significantly smaller for MDCT and standard-dose FPCT compared with CBCT low- and standard-dose acquisitions (all P < 0.05). No significant differences in artifact extent among different screw types and scanning positions were noted (P > 0.05). Both MDCT and FPCT standard-dose protocols showed equal ratings for screw bone interface, fracture line, and trabecular bone evaluation (P = 0.06, 0.2, and 0.2, respectively) and performed significantly better than FPCT low- and CBCT low- and standard-dose acquisitions (all P < 0.05). Good interreader agreement was found for image quality comparisons (Cohen κ = 0.76-0.78). Both MDCT and FPCT standard-dose acquisition showed comparatively less metal-induced artifacts and better overall image quality compared with FPCT low-dose and both CBCT acquisitions. Flat-panel CT may provide sufficient image quality to serve as a versatile CT alternative for postoperative imaging of internally fixated wrist fractures.

78 FR 36791 - Hardwood Plywood From China; Institution of Antidumping and Countervailing Duty Investigations...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-19

... and decorative plywood. ``Hardwood and decorative plywood is a flat panel composed of an assembly of two or more layers or plies of wood veneers in combination with a core. The veneers, along with the... plywood panel must have face and back veneers which are composed of one or more species of hardwoods...

Properties of flat-pressed wood plastic composites containing fire retardants

Treesearch

Nadir Ayrilmis; Jan. T. Benthien; Heiko Thoemen; Robert H. White

2011-01-01

This study investigated physical, mechanical, and fire properties of the flat-pressed wood plastic composites (WPCs) incorporated with various fire retardants (FRs) [5 or 15% by weight (wt)] at 50 wt % of the wood flour (WF). The WPC panels were made from dry-blended WF, polypropylene (PP) with maleic anhydride grafted PP (2 wt %), and FR powder formulations using a...

High bit rate mass data storage device

NASA Technical Reports Server (NTRS)

1973-01-01

The HDDR-II mass data storage system consists of a Leach MTR 7114 recorder reproducer, a wire wrapped, integrated circuit flat plane and necessary power supplies for the flat plane. These units, with interconnecting cables and control panel are enclosed in a common housing mounted on casters. The electronics used in the HDDR-II double density decoding and encoding techniques are described.

Military display market: third comprehensive edition

NASA Astrophysics Data System (ADS)

Desjardins, Daniel D.; Hopper, Darrel G.

2002-08-01

Defense displays comprise a niche market whose continually high performance requirements drive technology. The military displays market is being characterized to ascertain opportunities for synergy across platforms, and needs for new technology. All weapons systems are included. Some 382,585 displays are either now in use or planned in DoD weapon systems over the next 15 years, comprising displays designed into direct-view, projection-view, and virtual- image-view applications. This defense niche market is further fractured into 1163 micro-niche markets by the some 403 program offices who make decisions independently of one another. By comparison, a consumer electronics product has volumes of tens-of-millions of units for a single fixed design. Some 81% of defense displays are ruggedized versions of consumer-market driven designs. Some 19% of defense displays, especially in avionics cockpits and combat crewstations, are custom designs to gain the additional performance available in the technology base but not available in consumer-market-driven designs. Defense display sizes range from 13.6 to 4543 mm. More than half of defense displays are now based on some form of flat panel display technology, especially thin-film-transistor active matrix liquid crystal display (TFT AMLCD); the cathode ray tube (CRT) is still widely used but continuing to drop rapidly in defense market share.

Large-Area High-Performance Flexible Pressure Sensor with Carbon Nanotube Active Matrix for Electronic Skin.

PubMed

Nela, Luca; Tang, Jianshi; Cao, Qing; Tulevski, George; Han, Shu-Jen

2018-03-14

Artificial "electronic skin" is of great interest for mimicking the functionality of human skin, such as tactile pressure sensing. Several important performance metrics include mechanical flexibility, operation voltage, sensitivity, and accuracy, as well as response speed. In this Letter, we demonstrate a large-area high-performance flexible pressure sensor built on an active matrix of 16 × 16 carbon nanotube thin-film transistors (CNT TFTs). Made from highly purified solution tubes, the active matrix exhibits superior flexible TFT performance with high mobility and large current density, along with a high device yield of nearly 99% over 4 inch sample area. The fully integrated flexible pressure sensor operates within a small voltage range of 3 V and shows superb performance featuring high spatial resolution of 4 mm, faster response than human skin (<30 ms), and excellent accuracy in sensing complex objects on both flat and curved surfaces. This work may pave the road for future integration of high-performance electronic skin in smart robotics and prosthetic solutions.

Plastic substrates for active matrix liquid crystal display incapable of withstanding processing temperature of over 200 C and method of fabrication

DOEpatents

Carey, P.G.; Smith, P.M.; Havens, J.H.; Jones, P.

1999-01-05

Bright-polarizer-free, active-matrix liquid crystal displays (AMLCDs) are formed on plastic substrates. The primary components of the display are a pixel circuit fabricated on one plastic substrate, an intervening liquid-crystal material, and a counter electrode on a second plastic substrate. The-pixel circuit contains one or more thin-film transistors (TFTs) and either a transparent or reflective pixel electrode manufactured at sufficiently low temperatures to avoid damage to the plastic substrate. Fabrication of the TFTs can be carried out at temperatures less than 100 C. The liquid crystal material is a commercially made nematic curvilinear aligned phase (NCAP) film. The counter electrode is comprised of a plastic substrate coated with a transparent conductor, such as indium-doped tin oxide (ITO). By coupling the active matrix with NCAP, a high-information content can be provided in a bright, fully plastic package. Applications include any low cost portable electronics containing flat displays where ruggedization of the display is desired. 12 figs.

Plastic substrates for active matrix liquid crystal display incapable of withstanding processing temperature of over 200.degree. C and method of fabrication

DOEpatents

Carey, Paul G.; Smith, Patrick M.; Havens, John; Jones, Phil

1999-01-01

Bright-polarizer-free, active-matrix liquid crystal displays (AMLCDs) are formed on plastic substrates. The primary components of the display are a pixel circuit fabricated on one plastic substrate, an intervening liquid-crystal material, and a counter electrode on a second plastic substrate. The-pixel circuit contains one or more thin-film transistors (TFTs) and either a transparent or reflective pixel electrode manufactured at sufficiently low temperatures to avoid damage to the plastic substrate. Fabrication of the TFTs can be carried out at temperatures less than 100.degree. C. The liquid crystal material is a commercially made nematic curvilinear aligned phase (NCAP) film. The counter electrode is comprised of a plastic substrate coated with a transparent conductor, such as indium-doped tin oxide (ITO). By coupling the active matrix with NCAP, a high-information content can be provided in a bright, fully plastic package. Applications include any low cost portable electronics containing flat displays where ruggedization of the display is desired.

Spartan Auxiliary Mount Panel (SPAM): A Metal Matrix Composite Honeycomb Panel for Space Flight Use

NASA Technical Reports Server (NTRS)

Segal, Kenneth N.; Stevens, Edward J.

1998-01-01

This presentation focus on the use of metal matrix composite (MMC) material option in spaceflight hardware applications. It addresses the important questions and issues such as: what is SPAM; why the use of MMC; design requirements and flexibility; qualification testing; and flight concerns.

Eigenvalue computations with the QUAD4 consistent-mass matrix

NASA Technical Reports Server (NTRS)

Butler, Thomas A.

1990-01-01

The NASTRAN user has the option of using either a lumped-mass matrix or a consistent- (coupled-) mass matrix with the QUAD4 shell finite element. At the Sixteenth NASTRAN Users' Colloquium (1988), Melvyn Marcus and associates of the David Taylor Research Center summarized a study comparing the results of the QUAD4 element with results of other NASTRAN shell elements for a cylindrical-shell modal analysis. Results of this study, in which both the lumped-and consistent-mass matrix formulations were used, implied that the consistent-mass matrix yielded poor results. In an effort to further evaluate the consistent-mass matrix, a study was performed using both a cylindrical-shell geometry and a flat-plate geometry. Modal parameters were extracted for several modes for both geometries leading to some significant conclusions. First, there do not appear to be any fundamental errors associated with the consistent-mass matrix. However, its accuracy is quite different for the two different geometries studied. The consistent-mass matrix yields better results for the flat-plate geometry and the lumped-mass matrix seems to be the better choice for cylindrical-shell geometries.

Design, fabrication and delivery of a miniature Cassegrainian concentrator solar array system

NASA Technical Reports Server (NTRS)

Kruer, Mark A.

1987-01-01

The optical design of the miniature Cassegrainian concentrator (MCC) element was improved for both offpoint and onpoint power capability. The cell stack design has shown no losses under the high short term thermal stresses imposed by component level test and is projected to be capable of greater than five years thermal cycle life in low Earth orbit. The structural design met all requirements for stiffness and flatness and requires adjustable inserts for fine tuning of the GFRP structure to meet flatness goals. The completed, fully populated small and large MCC panels deliverable under this contract perform electrically as expected. A solid acceptance inspection program to guarantee quality of all purchased parts, and continued manufacturing process improvements will make the MCC design a viable low cost alternative to standard flat panel technology. Minor improvements to the cell stack design of the MCC element can make significant improvements in both the performance and manufacturability of the MCC system.

Effect of polymer type on characterization and filtration performances of multi-walled carbon nanotubes (MWCNT)-COOH-based polymeric mixed matrix membranes.

PubMed

Sengur-Tasdemir, Reyhan; Mokkapati, Venkata R S S; Koseoglu-Imer, Derya Y; Koyuncu, Ismail

2018-05-01

Multi-walled carbon nanotubes (MWCNTs) can be used for the fabrication of mixed matrix polymeric membranes that can enhance filtration perfomances of the membranes by modifying membrane surface properties. In this study, detailed characterization and filtration performances of MWCNTs functionalized with COOH group, blended into polymeric flat-sheet membranes were investigated using different polymer types. Morphological characterization was carried out using atomic force microscopy, scanning electron microscopy and contact angle measurements. For filtration performance tests, protein, dextran, E. coli suspension, Xanthan Gum and real activated sludge solutions were used. Experimental data and analyses revealed that Polyethersulfone (PES) + MWCNT-COOH mixed matrix membranes have superior performance abilities compared to other tested membranes.

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.

Shear buckling analysis of a hat-stiffened panel

NASA Technical Reports Server (NTRS)

Ko, William L.; Jackson, Raymond H.

1994-01-01

A buckling analysis was performed on a hat-stiffened panel subjected to shear loading. Both local buckling and global buckling were analyzed. The global shear buckling load was found to be several times higher than the local shear buckling load. The classical shear buckling theory for a flat plate was found to be useful in predicting the local shear buckling load of the hat-stiffened panel, and the predicted local shear buckling loads thus obtained compare favorably with the results of finite element analysis.

Multiwall thermal protection system

NASA Technical Reports Server (NTRS)

Jackson, L. R. (Inventor)

1982-01-01

Multiwall insulating sandwich panels are provided for thermal protection of hypervelocity vehicles and other enclosures. In one embodiment, the multiwall panels are formed of alternate layers of dimpled and flat metal (titanium alloy) foil sheets and beaded scarfed edge seals to provide enclosure thermal protection up to 1000 F. An additional embodiment employs an intermediate fibrous insulation for the sandwich panel to provide thermal protection up to 2000 F. A third embodiment employs a silicide coated columbium waffle as the outer panel skin and fibrous layered intermediate protection for thermal environment protection up to 2500 F. The use of multiple panels on an enclosure facilitate repair and refurbishment of the thermal protection system due to the simple support provided by the tab and clip attachment for the panels.

Method of forming a spacer for field emission flat panel displays

DOEpatents

Bernhardt, A.F.; Contolini, R.J.

1997-08-19

Spacers are disclosed for applications such as field emission flat panel displays and vacuum microelectronics, and which involves the application of aerogel/xerogel technology to the formation of the spacer. In a preferred approach the method uses a mold and mold release agent wherein the gel precursor is a liquid which can be applied to the mold filling holes which expose the substrate (either the baseplate or the faceplate). A release agent is applied to the mold prior to precursor application to ease removal of the mold after formation of the dielectric spacer. The shrinkage of the gel during solvent extraction also improves mold removal. The final spacer material is a good dielectric, such as silica, secured to the substrate. 3 figs.

Arthroscopic knee surgery using the advanced flat panel high-resolution color head-mounted display

NASA Astrophysics Data System (ADS)

Nelson, Scott A.; Jones, D. E. Casey; St. Pierre, Patrick; Sampson, James B.

1997-06-01

The first ever deployed arthroscopic knee surgeries have been performed using a high resolution color head-mounted display (HMD) developed under the DARPA Advanced Flat Panel HMD program. THese procedures and several fixed hospital procedures have allowed both the system designers and surgeons to gain new insight into the use of a HMD for medical procedures in both community and combat support hospitals scenarios. The surgeons demonstrated and reported improved head-body orientation and awareness while using the HMD and reported several advantages and disadvantages of the HMD as compared to traditional CRT monitor viewing of the arthroscopic video images. The surgeries, the surgeon's comments, and a human factors overview of HMDs for Army surgical applications are discussed here.

Method of forming a spacer for field emission flat panel displays

DOEpatents

Bernhardt, Anthony F.; Contolini, Robert J.

1997-01-01

Spacers for applications such as field emission flat panel displays and vacuum microelectronics, and which involves the application of aerogel/xerogel technology to the formation of the spacer. In a preferred approach the method uses a mold and mold release agent wherein the gel precursor is a liquid which can be applied to the mold filling holes which expose the substrate (either the baseplate or the faceplate). A release agent is applied to the mold prior to precursor application to ease removal of the mold after formation of the dielectric spacer. The shrinkage of the gel during solvent extraction also improves mold removal. The final spacer material is a good dielectric, such as silica, secured to the substrate.

Recent progress in low-voltage cathodoluminescent materials: synthesis, improvement and emission properties.

PubMed

Li, Guogang; Lin, Jun

2014-01-01

Nowadays there are several technologies used for flat panel displays (FPDs) and the development of FPDs with enhanced energy efficiency and improved display quality is strongly required. Field emission displays (FEDs) have been considered as one of the most promising next generation flat panel display technologies due to their excellent display performance and low energy consumption. For the development of FEDs, phosphors are irreplaceable components. In the past decade, the study of highly efficient low-voltage cathodoluminescent materials, namely FED phosphors, has become the focus of enhancing energy efficiency and realizing high-quality displays. This review summaries the recent progress in the chemical synthesis and improvement of novel, rare-earth and transition metal ions activated inorganic cathodoluminescent materials in powder and thin film forms. The discussion is focused on the modification of morphology, size, surface, composition and conductivity of phosphors and the corresponding effects on their cathodoluminescent properties. Special emphases are given to the selection of host and luminescent centers, the adjustment of emission colors through doping concentration optimization, energy transfer and mono- or co-doping activator ions, the improvement of chromaticity, color stability and color gamut as well as the saturation behavior and the degradation behavior of phosphors under the excitation of a low-voltage electron beam. Finally, the research prospects and future directions of FED phosphors are discussed with recommendations to facilitate the further study of new and highly efficient low-voltage cathodoluminescent materials.

Threshold-Voltage-Shift Compensation and Suppression Method Using Hydrogenated Amorphous Silicon Thin-Film Transistors for Large Active Matrix Organic Light-Emitting Diode Displays

NASA Astrophysics Data System (ADS)

Oh, Kyonghwan; Kwon, Oh-Kyong

2012-03-01

A threshold-voltage-shift compensation and suppression method for active matrix organic light-emitting diode (AMOLED) displays fabricated using a hydrogenated amorphous silicon thin-film transistor (TFT) backplane is proposed. The proposed method compensates for the threshold voltage variation of TFTs due to different threshold voltage shifts during emission time and extends the lifetime of the AMOLED panel. Measurement results show that the error range of emission current is from -1.1 to +1.7% when the threshold voltage of TFTs varies from 1.2 to 3.0 V.

Effect of stiffness characteristics on the response of composite grid-stiffened structures

NASA Technical Reports Server (NTRS)

Ambur, Damodar R.; Rehfield, Lawrence W.

1991-01-01

A study of the effect of stiffness discontinuities and structural parameters on the response of continuous-filament grid-stiffened flat panels is presented. The buckling load degradation due to manufacturing-introduced stiffener discontinuities associated with a filament cut-and-add approach at the stiffener intersections is investigated. The degradation of buckling resistance in isogrid flat panels subjected to uni-axial compression and combined axial compression and shear loading conditions and induced damage is quantified using FEM. The combined loading case is the most critical one. Nonsolid stiffener cross sections, such as a foam-filled blade or hat with a 0-deg dominant cap, result in grid-stiffened structures that are structurally very efficient for wing and fuselage applications. The results of a study of the ability of grid-stiffened structural concepts to enhance the effective Poisson's ratio of a panel are presented. Grid-stiffened concepts create a highly effective Poisson's ratio, which can produce large camber deformations for certain elastic tailoring applications.

TRMM Solar Array Panels

NASA Technical Reports Server (NTRS)

1998-01-01

This final report presents conclusions/recommendations concerning the TRMM Solar Array; deliverable list and schedule summary; waivers and deviations; as-shipped performance data, including flight panel verification matrix, panel output detail, shadow test summary, humidity test summary, reverse bias test panel; and finally, quality assurance summary.

Fabric panel clean change-out frame

DOEpatents

Brown, Ronald M.

1995-01-31

A fabric panel clean change-out frame, for use on a containment structure having rigid walls, is formed of a compression frame and a closure panel. The frame is formed of elongated spacers, each carrying a plurality of closely spaced flat springs, and each having a hooked lip extending on the side of the spring facing the spacer. The closure panel is includes a perimeter frame formed of flexible, wedge-shaped frame members that are receivable under the springs to deflect the hooked lips. A groove on the flexible frame members engages the hooked lips and locks the frame members in place under the springs. A flexible fabric panel is connected to the flexible frame members and closes its center.

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.

Effects of fire retardants on physical, mechanical, and fire properties of flat-pressed WPCs

Treesearch

Nadir Ayrilmis; Jan T. Benthien; Heiko Thoemen; Robert H. White

2012-01-01

Physical, mechanical, and fire properties of the flat-pressed wood plastic composites (WPCs) incorporated with various fire retardants (10% by weight) at different levels of wood flour (WF) content, 40, 50, or 60 wt%, were investigated. The WPC panels were made from dry-blended WF, polypropylene (PP), and fire retardant (FR) powders with maleic anhydride-grafted PP (2...

78 FR 16250 - Hardwood and Decorative Plywood From the People's Republic of China: Amended Preliminary...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-14

... plywood. Hardwood and decorative plywood is a flat panel composed of an assembly of two or more layers or plies of wood veneers in combination with a core. The veneers, along with the core, are glued or otherwise bonded together to form a finished product. A hardwood and decorative plywood panel must have face...

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.

Development of 4-Sides Buttable CdTe-ASIC Hybrid Module for X-ray Flat Panel Detector

NASA Astrophysics Data System (ADS)

Tamaki, Mitsuru; Mito, Yoshio; Shuto, Yasuhiro; Kiyuna, Tatsuya; Yamamoto, Masaya; Sagae, Kenichi; Kina, Tooru; Koizumi, Tatsuhiro; Ohno, Ryoichi

2009-08-01

A 4-sides buttable CdTe-ASIC hybrid module suitable for use in an X-ray flat panel detector (FPD) has been developed by applying through silicon via (TSV) technology to the readout ASIC. The ASIC has 128 times 256 channels of charge integration type readout circuitry and an area of 12.9 mm times 25.7 mm. The CdTe sensor of 1 mm thickness, having the same area and pixel of 100 mum pitch, was fabricated from the Cl-doped CdTe single crystal grown by traveling heater method (THM). Then the CdTe pixel sensor was hybridized with the ASIC using the bump-bonding technology. The basic performance of this 4-sides buttable module was evaluated by taking X-ray images, and it was compared with that of a commercially available indirect type CsI(Tl) FPD. A prototype CdTe FPD was made by assembling 9 pieces of the 4-sides buttable modules into 3 times 3 arrays in which the neighboring modules were mounted on the interface board. The FPD covers an active area of 77 mm times 39 mm. The results showed the great potential of this 4-sides buttable module for the new real time X-ray FPD with high spatial resolution.

Dynamics Impact Tolerance of Shuttle RCC Leading Edge Panels Using LS-DYNA

NASA Technical Reports Server (NTRS)

Fasanella, Edwin L.; Jackson, Karen E.; Lyle, Karen H.; Jones, Lisa E.; Hardy, Robin C.; Spellman, Regina L.; Carney, Kelly S.; Melis, Matthew E.; Stockwell, Alan E.

2005-01-01

This paper describes a research program conducted to enable accurate prediction of the impact tolerance of the shuttle Orbiter leading-edge wing panels using physics-based codes such as LS-DYNA, a nonlinear, explicit transient dynamic finite element code. The shuttle leading-edge panels are constructed of Reinforced-Carbon-Carbon (RCC) composite material, which is used because of its thermal properties to protect the shuttle during reentry into the Earth's atmosphere. Accurate predictions of impact damage from insulating foam and other debris strikes that occur during launch required materials characterization of expected debris, including strain-rate effects. First, analytical models of individual foam and RCC materials were validated. Next, analytical models of foam cylinders impacting 6- in. x 6-in. RCC flat plates were developed and validated. LS-DYNA pre-test models of the RCC flat plate specimens established the impact velocity of the test for three damage levels: no-detectable damage, non-destructive evaluation (NDE) detectable damage, or visible damage such as a through crack or hole. Finally, the threshold of impact damage for RCC on representative Orbiter wing panels was predicted for both a small through crack and for NDE-detectable damage.

Dynamic Impact Tolerance of Shuttle RCC Leading Edge Panels using LS-DYNA

NASA Technical Reports Server (NTRS)

Fasanella, Edwin; Jackson, Karen E.; Lyle, Karen H.; Jones, Lisa E.; Hardy, Robin C.; Spellman, Regina L.; Carney, Kelly S.; Melis, Matthew E.; Stockwell, Alan E.

2008-01-01

This paper describes a research program conducted to enable accurate prediction of the impact tolerance of the shuttle Orbiter leading-edge wing panels using 'physics-based- codes such as LS-DYNA, a nonlinear, explicit transient dynamic finite element code. The shuttle leading-edge panels are constructed of Reinforced-Carbon-Carbon (RCC) composite material, which issued because of its thermal properties to protect the shuttle during re-entry into the Earth's atmosphere. Accurate predictions of impact damage from insulating foam and other debris strikes that occur during launch required materials characterization of expected debris, including strain-rate effects. First, analytical models of individual foam and RCC materials were validated. Next, analytical models of individual foam cylinders impacting 6-in. x 6-in. RCC flat plates were developed and validated. LS-DYNA pre-test models of the RCC flat plate specimens established the impact velocity of the test for three damage levels: no-detectable damage, non-destructive evaluation (NDE) detectable damage, or visible damage such as a through crack or hole. Finally, the threshold of impact damage for RCC on representative Orbiter wing panels was predicted for both a small through crack and for NDE-detectable damage.

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.

Micromachined edge illuminated optically transparent automotive light guide panels

NASA Astrophysics Data System (ADS)

Ronny, Rahima Afrose; Knopf, George K.; Bordatchev, Evgueni; Tauhiduzzaman, Mohammed; Nikumb, Suwas

2012-03-01

Edge-lit backlighting has been used extensively for a variety of small and medium-sized liquid crystal displays (LCDs). The shape, density and spatial distribution pattern of the micro-optical elements imprinted on the surface of the flat light-guide panel (LGP) are often "optimized" to improve the overall brightness and luminance uniformity. A similar concept can be used to develop interior convenience lighting panels and exterior tail lamps for automotive applications. However, costly diffusive sheeting and brightness enhancement films are not be considered for these applications because absolute luminance uniformity and the minimization of Moiré fringe effects are not significant factors in assessing quality of automotive lighting. A new design concept that involves micromilling cylindrical micro-optical elements on optically transparent plastic substrates is described in this paper. The variable parameter that controls illumination over the active regions of the panel is the depth of the individual cylindrical micro-optical elements. LightTools™ is the optical simulation tool used to explore how changing the micro-optical element depth can alter the local and global luminance. Numerical simulation and microfabrication experiments are performed on several (100mmx100mmx6mm) polymethylmethacrylate (PMMA) test samples in order to verify the illumination behavior.

Structural efficiency study of composite wing rib structures

NASA Technical Reports Server (NTRS)

Swanson, Gary D.; Gurdal, Zafer; Starnes, James H., Jr.

1988-01-01

A series of short stiffened panel designs which may be applied to a preliminary design assessment of an aircraft wing rib is presented. The computer program PASCO is used as the primary design and analysis tool to assess the structural efficiency and geometry of a tailored corrugated panel, a corrugated panel with a continuous laminate, a hat stiffened panel, a blade stiffened panel, and an unstiffened flat plate. To correct some of the shortcomings in the PASCO analysis when shear is present, a two step iterative process using the computer program VICON is used. The loadings considered include combinations of axial compression, shear, and lateral pressure. The loading ranges considered are broad enough such that the designs presented may be applied to other stiffened panel applications. An assessment is made of laminate variations, increased spacing, and nonoptimum geometric variations, including a beaded panel, on the design of the panels.

DQE and system optimization for indirect-detection flat-panel imagers in diagnostic radiology

NASA Astrophysics Data System (ADS)

Siewerdsen, Jeffrey H.; Antonuk, Larry E.

1998-07-01

The performance of indirect-detection flat-panel imagers incorporating CsI:Tl x-ray converters is examined through calculation of the detective quantum efficiency (DQE) under conditions of chest radiography, fluoroscopy, and mammography. Calculations are based upon a cascaded systems model which has demonstrated excellent agreement with empirical signal, noise- power spectra, and DQE results. For each application, the DQE is calculated as a function of spatial-frequency and CsI:Tl thickness. A preliminary investigation into the optimization of flat-panel imaging systems is described, wherein the x-ray converter thickness which provides optimal DQE for a given imaging task is estimated. For each application, a number of example tasks involving detection of an object of variable size and contrast against a noisy background are considered. The method described is fairly general and can be extended to account for a variety of imaging tasks. For the specific examples considered, the preliminary results estimate optimal CsI:Tl thicknesses of approximately 450 micrometer (approximately 200 mg/cm2), approximately 320 micrometer (approximately 140 mg/cm2), and approximately 200 micrometer (approximately 90 mg/cm2) for chest radiography, fluoroscopy, and mammography, respectively. These results are expected to depend upon the imaging task as well as upon the quality of available CsI:Tl, and future improvements in scintillator fabrication could result in increased optimal thickness and DQE.

Performance of mobile digital X-ray fluoroscopy using a novel flat panel detector for intraoperative use.

PubMed

Jeong, Chang-Won; Ryu, Jong-Hyun; Joo, Su-Chong; Jun, Hong-Young; Heo, Dong-Woon; Lee, Jinseok; Kim, Kyong-Woo; Yoon, Kwon-Ha

2015-01-01

Technologies employing digital X-ray devices are developed for mobile settings. To develop a mobile digital X-ray fluoroscopy (MDF) for intraoperative guidance, using a novel flat panel detector to focus on diagnostics in outpatient clinics, operating and emergency rooms. An MDF for small-scale field diagnostics was configured using an X-ray source and a novel flat panel detector. The imager enabled frame rates reaching 30 fps in full resolution fluoroscopy with maximal running time of 5 minutes. Signal-to-noise (SNR), contrast-to-noise (CNR), and spatial resolution were analyzed. Stray radiation, exposure radiation dose, and effective absorption dose were measured for patients. The system was suitable for small-scale field diagnostics. SNR and CNR were 62.4 and 72.0. Performance at 10% of MTF was 9.6 lp/mm (53 μ m) in the no binned mode. Stray radiation at 100 cm and 150 cm from the source was below 0.2 μ Gy and 0.1 μ Gy. Exposure radiation in radiography and fluoroscopy (5 min) was 10.2 μ Gy and 82.6 mGy. The effective doses during 5-min-long fluoroscopy were 0.26 mSv (wrist), 0.28 mSv (elbow), 0.29 mSv (ankle), and 0.31 mSv (knee). The proposed MDF is suitable for imaging in operating rooms.

An iterative algorithm for soft tissue reconstruction from truncated flat panel projections

NASA Astrophysics Data System (ADS)

Langan, D.; Claus, B.; Edic, P.; Vaillant, R.; De Man, B.; Basu, S.; Iatrou, M.

2006-03-01

The capabilities of flat panel interventional x-ray systems continue to expand, enabling a broader array of medical applications to be performed in a minimally invasive manner. Although CT is providing pre-operative 3D information, there is a need for 3D imaging of low contrast soft tissue during interventions in a number of areas including neurology, cardiac electro-physiology, and oncology. Unlike CT systems, interventional angiographic x-ray systems provide real-time large field of view 2D imaging, patient access, and flexible gantry positioning enabling interventional procedures. However, relative to CT, these C-arm flat panel systems have additional technical challenges in 3D soft tissue imaging including slower rotation speed, gantry vibration, reduced lateral patient field of view (FOV), and increased scatter. The reduced patient FOV often results in significant data truncation. Reconstruction of truncated (incomplete) data is known an "interior problem", and it is mathematically impossible to obtain an exact reconstruction. Nevertheless, it is an important problem in 3D imaging on a C-arm to address the need to generate a 3D reconstruction representative of the object being imaged with minimal artifacts. In this work we investigate the application of an iterative Maximum Likelihood Transmission (MLTR) algorithm to truncated data. We also consider truncated data with limited views for cardiac imaging where the views are gated by the electrocardiogram(ECG) to combat motion artifacts.

Single-cell computational analysis of light harvesting in a flat-panel photo-bioreactor.

PubMed

Loomba, Varun; Huber, Gregor; von Lieres, Eric

2018-01-01

Flat-panel photo-bioreactors (PBRs) are customarily applied for investigating growth of microalgae. Optimal design and operation of such reactors is still a challenge due to complex non-linear combinations of various impact factors, particularly hydrodynamics, light irradiation, and cell metabolism. A detailed analysis of single-cell light reception can lead to novel insights into the complex interactions of light exposure and algae movement in the reactor. The combined impacts of hydrodynamics and light irradiation on algae cultivation in a flat-panel PBR were studied by tracing the light exposure of individual cells over time. Hydrodynamics and turbulent mixing in this air-sparged bioreactor were simulated using the Eulerian approach for the liquid phase and a slip model for the gas phase velocity profiles. The liquid velocity was then used for tracing single cells and their light exposure, using light intensity profiles obtained from solving the radiative transfer equation at different wavelengths. The residence times of algae cells in defined dark and light zones of the PBR were statistically analyzed for different algal concentrations and sparging rates. The results indicate poor mixing caused by the reactor design which can be only partially improved by increased sparging rates. The results provide important information for optimizing algal biomass productivity by improving bioreactor design and operation and can further be utilized for an in-depth analysis of algal growth by using advanced models of cell metabolism.

Development of a single-phase thermosiphon for cold collection and storage of radiative cooling

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

Zhao, Dongliang; Martini, Christine Elizabeth; Jiang, Siyu

A single-phase thermosiphon is developed for cold collection and storage of radiative cooling. Compared to the conventional nocturnal radiative cooling systems that use an electric pump to drive the heat transfer fluid, the proposed single-phase thermosiphon uses the buoyancy force to drive heat transfer fluid. This solution does not require electricity, therefore improving the net gain of the radiative cooling system. A single-phase thermosiphon was built, which consists of a flat panel, a cold collection tank, a water return tube, and a water distribution tank. Considering that outdoor radiative cooling flux is constantly changing (i.e. uncontrollable), an indoor testing facilitymore » was developed to provide a controllable cooling flux (comparable to a radiative cooling flux of 100 W/m2) for the evaluation of thermosiphon performance. The testing apparatus is a chilled aluminum flat plate that has a controlled air gap separation relative to the flat panel surface of the thermosiphon to emulate radiative cooling. With an average of 105 W/m2 cooling flux, the 18 liters of water in the thermosiphon was cooled to an average temperature of 12.5 degrees C from an initial temperature of 22.2 degrees C in 2 h, with a cold collection efficiency of 96.8%. The results obtained have demonstrated the feasibility of using a single-phase thermosiphon for cold collection and storage of radiative cooling. Additionally, the effects of the thermosiphon operation conditions, such as tilt angle of the flat panel, initial water temperature, and cooling energy flux, on the performance have been experimentally investigated. Modular design of the single-phase thermosiphon gives flexibility for its scalability. A radiative cooling system with multiple thermosiphon modules is expected to play an important role in cooling buildings and power plant condensers.« less

Preliminary design review package on air flat plate collector for solar heating and cooling system

NASA Technical Reports Server (NTRS)

1977-01-01

Guidelines to be used in the development and fabrication of a prototype air flat plate collector subsystem containing 320 square feet (10-4 ft x 8 ft panels) of collector area are presented. Topics discussed include: (1) verification plan; (2) thermal analysis; (3) safety hazard analysis; (4) drawing list; (5) special handling, installation and maintenance tools; (6) structural analysis; and (7) selected drawings.

A passive cooling system proposal for multifunction and high-power displays

NASA Astrophysics Data System (ADS)

Tari, Ilker

2013-03-01

Flat panel displays are conventionally cooled by internal natural convection, which constrains the possible rate of heat transfer from the panel. On one hand, during the last few years, the power consumption and the related cooling requirement for 1080p displays have decreased mostly due to energy savings by the switch to LED backlighting and more efficient electronics. However, on the other hand, the required cooling rate recently started to increase with new directions in the industry such as 3D displays, and ultra-high-resolution displays (recent 4K announcements and planned introduction of 8K). In addition to these trends in display technology itself, there is also a trend to integrate consumer entertainment products into displays with the ultimate goal of designing a multifunction device replacing the TV, the media player, the PC, the game console and the sound system. Considering the increasing power requirement for higher fidelity in video processing, these multifunction devices tend to generate very high heat fluxes, which are impossible to dissipate with internal natural convection. In order to overcome this obstacle, instead of active cooling with forced convection that comes with drawbacks of noise, additional power consumption, and reduced reliability, a passive cooling system relying on external natural convection and radiation is proposed here. The proposed cooling system consists of a heat spreader flat heat pipe and aluminum plate-finned heat sink with anodized surfaces. For this system, the possible maximum heat dissipation rates from the standard size panels (in 26-70 inch range) are estimated by using our recently obtained heat transfer correlations for the natural convection from aluminum plate-finned heat sinks together with the surface-to-surface radiation. With the use of the proposed passive cooling system, the possibility of dissipating very high heat rates is demonstrated, hinting a promising green alternative to active cooling.

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.

Broadly tunable thin-film intereference coatings: active thin films for telecom applications

NASA Astrophysics Data System (ADS)

Domash, Lawrence H.; Ma, Eugene Y.; Lourie, Mark T.; Sharfin, Wayne F.; Wagner, Matthias

2003-06-01

Thin film interference coatings (TFIC) are the most widely used optical technology for telecom filtering, but until recently no tunable versions have been known except for mechanically rotated filters. We describe a new approach to broadly tunable TFIC components based on the thermo-optic properties of semiconductor thin films with large thermo-optic coefficients 3.6X10[-4]/K. The technology is based on amorphous silicon thin films deposited by plasma-enhanced chemical vapor deposition (PECVD), a process adapted for telecom applications from its origins in the flat-panel display and solar cell industries. Unlike MEMS devices, tunable TFIC can be designed as sophisticated multi-cavity, multi-layer optical designs. Applications include flat-top passband filters for add-drop multiplexing, tunable dispersion compensators, tunable gain equalizers and variable optical attenuators. Extremely compact tunable devices may be integrated into modules such as optical channel monitors, tunable lasers, gain-equalized amplifiers, and tunable detectors.

OLED study for military applications

NASA Astrophysics Data System (ADS)

Barre, F.; Chiquard, A.; Faure, S.; Landais, L.; Patry, P.

2005-07-01

The presentation deals with some applications of OLED displays in military optronic systems, which are scheduled by SAGEM DS (Defence and Security). SAGEM DS, one of the largest group in the defence and security market, is currently investigating OLED Technologies for military programs. This technology is close from being chosen for optronic equipment such as future infantry night vision goggles, rifle-sight, or, more generally, vision enhancement systems. Most of those applications requires micro-display with an active matrix size below 1". Some others, such as, for instance, ruggedized flat displays do have a need for higher active matrix size (1,5" to 15"). SAGEM DS takes advantages of this flat, high luminance and emissive technology in highly integrated systems. In any case, many requirements have to be fulfilled: ultra-low power consumption, wide viewing angle, good pixel to pixel uniformity, and satisfactory behaviour in extreme environmental conditions.... Accurate measurements have been achieved at SAGEM DS on some micro display OLEDs and will be detailed: luminance (over 2000 cd/m2 achieved), area uniformity and pixel to pixel uniformity, robustness at low and high temperature (-40°C to +60°C), lifetime. These results, which refer to military requirements, provide a valuable feedback representative of the state of the art OLED performances.

TFT-Directed Electroplating of RGB Luminescent Films without a Vacuum or Mask toward a Full-Color AMOLED Pixel Matrix.

PubMed

Wang, Rong; Zhang, Donglian; Xiong, You; Zhou, Xuehong; Liu, Cao; Chen, Weifeng; Wu, Weijing; Zhou, Lei; Xu, Miao; Wang, Lei; Liu, Linlin; Peng, Junbiao; Ma, Yuguang; Cao, Yong

2018-05-30

The thin-film transistor (TFT) driving circuit is a separate electronic component embedded within the panel itself to switch the current for each pixel in active-matrix organic light-emitting diode displays. We reported a TFT-directed dye electroplating method to fabricate pixels; this would be a new method to deposit films on prepatterned electrode for organic full-color display, where TFT driving circuit provide a switching current signal to drive and direct dye depositing on selected RGB pixels. A prototype patterned color pixel matrix was achieved, as high-quality light-emitting films with uniform morphology, pure RGB chromaticity, and stable output.

A compact high resolution flat panel PET detector based on the new 4-side buttable MPPC for biomedical applications

PubMed Central

Wang, Qiang; Wen, Jie; Ravindranath, Bosky; O’Sullivan, Andrew W.; Catherall, David; Li, Ke; Wei, Shouyi; Komarov, Sergey; Tai, Yuan-Chuan

2015-01-01

Compact high-resolution panel detectors using virtual pinhole (VP) PET geometry can be inserted into existing clinical or pre-clinical PET systems to improve regional spatial resolution and sensitivity. Here we describe a compact panel PET detector built using the new Though Silicon Via (TSV) multi-pixel photon counters (MPPC) detector. This insert provides high spatial resolution and good timing performance for multiple bio-medical applications. Because the TSV MPPC design eliminates wire bonding and has a package dimension which is very close to the MPPC’s active area, it is 4-side buttable. The custom designed MPPC array (based on Hamamatsu S12641-PA-50(x)) used in the prototype is composed of 4 × 4 TSV-MPPC cells with a 4.46 mm pitch in both directions. The detector module has 16 × 16 lutetium yttrium oxyorthosilicate (LYSO) crystal array, with each crystal measuring 0.92 × 0.92 × 3 mm3 with 1.0 mm pitch. The outer diameter of the detector block is 16.8 × 16.8 mm2. Thirty-two such blocks will be arranged in a 4 × 8 array with 1 mm gaps to form a panel detector with detection area around 7 cm × 14 cm in the full-size detector. The flood histogram acquired with Ge-68 source showed excellent crystal separation capability with all 256 crystals clearly resolved. The detector module’s mean, standard deviation, minimum (best) and maximum (worst) energy resolution were 10.19%, +/−0.68%, 8.36% and 13.45% FWHM, respectively. The measured coincidence time resolution between the block detector and a fast reference detector (around 200 ps single photon timing resolution) was 0.95 ns. When tested with Siemens Cardinal electronics the performance of the detector blocks remain consistent. These results demonstrate that the TSV-MPPC is a promising photon sensor for use in a flat panel PET insert composed of many high resolution compact detector modules. PMID:26085702

Probing the smearing effect by a pointlike graviton in the plane-wave matrix model

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

Lee, Bum-Hoon; Nam, Siyoung; Shin, Hyeonjoon

2010-08-15

We investigate the interaction between a flat membrane and pointlike graviton in the plane-wave matrix model. The one-loop effective potential in the large-distance limit is computed and is shown to be of r{sup -3} type where r is the distance between two objects. This type of interaction has been interpreted as the one incorporating the smearing effect due to the configuration of a flat membrane in a plane-wave background. Our results support this interpretation and provide more evidence about it.

Explicit formulation of an anisotropic Allman/DKT 3-node thin triangular flat shell elements

NASA Astrophysics Data System (ADS)

Ertas, A.; Krafcik, J. T.; Ekwaro-Osire, S.

A simple, explicit formulation of the stiffness matrix for an anisotropic, 3-node, thin triangular, flat shell element in global coordinates is presented. An Allman triangle is used for membrane stiffness. The membrane stiffness matrix is explicitly derived by applying an Allman transformation to a Felippa 6-node linear strain triangle (LST). Bending stiffness is incorporated by the use of a discrete Kirchhoff triangle (DKT) bending triangle. Stiffness terms resulting from anisotropic membrane-bending coupling are included by integrating, in area coordinates, membrane and bending strain-displacement matrices.

Purging of multilayer insulation by gas diffusion

NASA Technical Reports Server (NTRS)

Sumner, I. E.; Spuckler, C. M.

1976-01-01

An experimental investigation was conducted to determine the time required to purge a multilayer insulation (MLI) panel with gaseous helium by means of gas diffusion to obtain a condensable (nitrogen) gas concentration of less than 1 percent within the panel. Two flat, rectangular MLI panel configurations, one incorporating a butt joint, were tested. The insulation panels consisted of 15 double-aluminized Mylar radiation shields separated by double silk net spacers. The test results indicated that the rate which the condensable gas concentration at the edge or at the butt joint of an MLI panel was reduced was a significant factor in the total time required to reduce the condensable gas concentration within the panel to less than 1 percent. The experimental data agreed well with analytical predictions made by using a simple, one-dimensional gas diffusion model in which the boundary conditions at the edge of the MLI panel were time dependent.

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.

Flat-panel detector, CCD cameras, and electron-beam-tube-based video for use in portal imaging

NASA Astrophysics Data System (ADS)

Roehrig, Hans; Tang, Chuankun; Cheng, Chee-Way; Dallas, William J.

1998-07-01

This paper provides a comparison of some imaging parameters of four portal imaging systems at 6 MV: a flat panel detector, two CCD cameras and an electron beam tube based video camera. Measurements were made of signal and noise and consequently of signal-to-noise per pixel as a function of the exposure. All systems have a linear response with respect to exposure, and with the exception of the electron beam tube based video camera, the noise is proportional to the square-root of the exposure, indicating photon-noise limitation. The flat-panel detector has a signal-to-noise ratio, which is higher than that observed with both CCD-Cameras or with the electron beam tube based video camera. This is expected because most portal imaging systems using optical coupling with a lens exhibit severe quantum-sinks. The measurements of signal-and noise were complemented by images of a Las Vegas-type aluminum contrast detail phantom, located at the ISO-Center. These images were generated at an exposure of 1 MU. The flat-panel detector permits detection of Aluminum holes of 1.2 mm diameter and 1.6 mm depth, indicating the best signal-to-noise ratio. The CCD-cameras rank second and third in signal-to- noise ratio, permitting detection of Aluminum-holes of 1.2 mm diameter and 2.2 mm depth (CCD_1) and of 1.2 mm diameter and 3.2 mm depth (CCD_2) respectively, while the electron beam tube based video camera permits detection of only a hole of 1.2 mm diameter and 4.6 mm depth. Rank Order Filtering was applied to the raw images from the CCD-based systems in order to remove the direct hits. These are camera responses to scattered x-ray photons which interact directly with the CCD of the CCD-Camera and generate 'Salt and Pepper type noise,' which interferes severely with attempts to determine accurate estimates of the image noise. The paper also presents data on the metal-phosphor's photon gain (the number of light-photons per interacting x-ray photon).

TU-E-217BCD-06: Cone Beam Breast CT with a High Resolution Flat Panel Detector-Improvement of Calcification Visibility.

PubMed

Shen, Y; Zhong, Y; Lai, C; Wang, T; Shaw, C

2012-06-01

To investigate the advantage of a high resolution flat panel detector for improving the visibility of microcalcifications (MCs) in cone beam breast CT Methods: A paraffin cylinder was used to simulate a 100% adipose breast. Calcium carbonate grains, ranging from 125-140 μm to 224 - 250 μm in size, were used to simulate the MCs. Groups of 25 same size MCs were embedded at the phantom center. The phantom was scanned with a bench-top CBCT system at various exposure levels. A 75μm pitch flat panel detector (Dexela 2923, Perkin Elmer) with 500μm thick CsI scintillator plate was used as the high resolution detector. A 194 μm pitch detector (Paxscan 4030CB, Varian Medical Systems) was used for reference. 300 projection images were acquired over 360° and reconstructed. The images were reviewed by 6 readers. The MC visibility was quantified as the fraction of visible MCs and averaged for comparison. The visibility was plotted as a function of the estimated dose level for various MC sizes and detectors. The MTFs and DQEs were measured and compared. For imaging small (200 μm and smaller) MCs, the visibility achieved with the 75μm pitch detector was found to be significantly higher than those achieved with the 194μm pitch detector. For imaging larger MCs, there was little advantage in using the 75μm pitch detector. Using the 75μm pitch detector, MCs as small as 180 μm could be imaged to achieve a visibility of 78% with an isocenter tissue dose of ∼20 mGys versus 62% achieved with the 194 μm pitch detector at the same dose level. It was found that a high pitch flat panel detector had the advantages of extending its imaging capability to higher frequencies thus helping improve the visibility when used to image small MCs. This work was supported in part by grants CA104759, CA13852 and CA124585 from NIH-NCI, a grant EB00117 from NIH-NIBIB, and a subcontract from NIST-ATP. © 2012 American Association of Physicists in Medicine.

Flexible AMOLED backplane using pentacene TFT

NASA Astrophysics Data System (ADS)

Song, Chung Kun; Ryu, Gi Seong

2005-01-01

In this paper we fabricated a panel consisting of an array of organic TFTs (OTFT) and organic LEDs (OLED) in order to demonstrate the possible application of OTFTs to flexible active matrix OLED (AMOLED). The panel was composed of 64×64 pixels on 4 inch size PET substrate in which each pixel had one OTFT integrated with one green OLED. The panel successfully demonstrated to display some letters and pictures by emitting green light with luminance of 20 cd/m2 at 6 V, which was controlled by the gate voltage of OTFT. In addition we also developed fabrication processes for pentacene TFT with PVP gate on PET substrate. The OTFTs produced the maximum mobility of 1.2 cm2/V"sec and on/off current ratio of 2×106.

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.

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.

Thermal Analysis of Antenna Structures. Part 2: Panel Temperature Distribution

NASA Technical Reports Server (NTRS)

Schonfeld, D.; Lansing, F. L.

1983-01-01

This article is the second in a series that analyzes the temperature distribution in microwave antennas. An analytical solution in a series form is obtained for the temperature distribution in a flat plate analogous to an antenna surface panel under arbitrary temperature and boundary conditions. The solution includes the effects of radiation and air convection from the plate. Good agreement is obtained between the numerical and analytical solutions.

Sunlight readable avionics displays

NASA Astrophysics Data System (ADS)

Visinski, Joseph R.

1998-09-01

The theme of the Cockpit Displays V Conference of 'Custom versus Consumer -- Grade Displays in Defense Applications' reflects the Raytheon Systems Company field emission display (FED) development effort. Raytheon chose to license commercial FED technology and subsequently participate in a commercial industry 'FED Alliance' to insert this technology into commercial and avionics defense applications. The unaffordability of custom military displays makes them an unfeasible choice to build a business upon. The major differences between consumer FEDs and those adapted for military/avionics installations are: (1) high brightness for sunlight visibility; (2) extended environmental range; (3) high resolution; (4) wider dimming range for sunlight to NVIS operation; (5) extended gray scales; (6) lifetime product support well beyond two year consumer market life. The transition to defense applications is further being accomplished via industry/government partnerships as the DARPA Technology Reinvestment Project (TRP) and BAA 97-31. FEDs combine cathode ray tube (CRT) and matrix addressed flat panel display technology, parts, manufacturing, and test equipment, plus open systems interfaces into a new display.

Vibrations and structureborne noise in space station

NASA Technical Reports Server (NTRS)

Vaicaitis, R.; Lyrintzis, C. S.; Bofilios, D. A.

1987-01-01

Analytical models were developed to predict vibrations and structureborne noise generation of cylindrical and rectangular acoustic enclosures. These models are then used to determine structural vibration levels and interior noise to random point input forces. The guidelines developed could provide preliminary information on acoustical and vibrational environments in space station habitability modules under orbital operations. The structural models include single wall monocoque shell, double wall shell, stiffened orthotropic shell, descretely stiffened flat panels, and a coupled system composed of a cantilever beam structure and a stiffened sidewall. Aluminum and fiber reinforced composite materials are considered for single and double wall shells. The end caps of the cylindrical enclosures are modeled either as single or double wall circular plates. Sound generation in the interior space is calculated by coupling the structural vibrations to the acoustic field in the enclosure. Modal methods and transfer matrix techniques are used to obtain structural vibrations. Parametric studies are performed to determine the sensitivity of interior noise environment to changes in input, geometric and structural conditions.

New process for alleviation of membrane fouling of modified hybrid MBR system for advanced domestic wastewater treatment.

PubMed

Shuo, Liu; Baozhen, Wang; Hongjun, Han; Yanping, Liu

2008-01-01

A pilot-scale hybrid membrane bioreactor using a submerged flat panel membrane was designed and applied for advanced treatment of domestic wastewater. The new process adapted to the hybrid membrane bioreactor exhibits substantial decrease in membrane fouling and much easier cleaning. In this study, the new process configurations including the addition of anoxic/anaerobic zones, the package of synthetic fibrous fabric carrier for biofilm attached growth, activated sludge recycling and modified dosage of polished diatomite with high activity and multi-functions were investigated to select the optimal operational parameters for the hybrid membrane bioreactor system. The carrier package in the aerobic zone contributed 3.65 g/L (maximum) of fixed biomass to the system, thus reducing the suspended biomass, and has decreased the membrane cleaning cycle remarkably. The operation performance at the sludge recycle rate 0, 100%, 200% and 300% showed that, the trans-membrane pressure of flat panel membrane declined sharply with the increase of sludge recycling rate within a certain range, and 200% was decided to be optimal for in the membrane bioreactor system. EPS concentration in each sludge recycling rate was 135 mg/L, 92 mg/L, 68 mg/L and 55 mg/L respectively. The addition of anoxic and anaerobic zones degraded some large molecular organic compounds, which facilitated the biodegradation and removal of organic substances in aerobic zone. The modified dosage of polished diatomite has played a major important role for both preventing of membrane from fouling and its much easier cleaning when it formed. Copyright (c) IWA Publishing 2008.

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.

Technical trends of large-size photomasks for flat panel displays

NASA Astrophysics Data System (ADS)

Yoshida, Koichiro

2017-06-01

Currently, flat panel displays (FPDs) are one of the main parts for information technology devices and sets. From 1990's to 2000's, liquid crystal displays (LCDs) and plasma displays had been mainstream FPDs. In the middle of 2000's, demand of plasma displays declined and organic light emitting diodes (OLEDs) newly came into FPD market. And today, major technology of FPDs are LCDs and OLEDs. Especially for mobile devices, the penetration of OLEDs is remarkable. In FPDs panel production, photolithography is the key technology as same as LSI. Photomasks for FPDs are used not only as original master of circuit pattern, but also as a tool to form other functional structures of FPDs. Photomasks for FPDs are called as "Large Size Photomasks(LSPMs)", since the remarkable feature is " Size" which reaches over 1- meter square and over 100kg. In this report, we discuss three LSPMs technical topics with FPDs technical transition and trend. The first topics is upsizing of LSPMs, the second is the challenge for higher resolution patterning, and the last is "Multi-Tone Mask" for "Half -Tone Exposure".

Flat or curved thin optical display panel

DOEpatents

Veligdan, J.T.

1995-01-10

An optical panel includes a plurality of waveguides stacked together, with each waveguide having a first end and an opposite second end. The first ends collectively define a first face, and the second ends collectively define a second face of the panel. The second face is disposed at an acute face angle relative to the waveguides to provide a panel which is relatively thin compared to the height of the second face. In an exemplary embodiment for use in a projection TV, the first face is substantially smaller in height than the second face and receives a TV image, with the second face defining a screen for viewing the image enlarged. 7 figures.

Low-frequency noise reduction of lightweight airframe structures

NASA Technical Reports Server (NTRS)

Getline, G. L.

1976-01-01

The results of an experimental study to determine the noise attenuation characteristics of aircraft type fuselage structural panels were presented. Of particular interest was noise attenuation at low frequencies, below the fundamental resonances of the panels. All panels were flightweight structures for transport type aircraft in the 34,050 to 45,400 kg (75,000 to 100,000 pounds) gross weight range. Test data include the results of vibration and acoustic transmission loss tests on seven types of isotropic and orthotropically stiffened, flat and curved panels. The results show that stiffness controlled acoustically integrated structures can provide very high noise reductions at low frequencies without significantly affecting their high frequency noise reduction capabilities.

Non-uniformity calibration for MWIR polarization imagery obtained with integrated microgrid polarimeters

NASA Astrophysics Data System (ADS)

Liu, Hai-Zheng; Shi, Ze-Lin; Feng, Bin; Hui, Bin; Zhao, Yao-Hong

2016-03-01

Integrating microgrid polarimeters on focal plane array (FPA) of an infrared detector causes non-uniformity of polarization response. In order to reduce the effect of polarization non-uniformity, this paper constructs an experimental setup for capturing raw flat-field images and proposes a procedure for acquiring non-uniform calibration (NUC) matrix and calibrating raw polarization images. The proposed procedure takes the incident radiation as a polarization vector and offers a calibration matrix for each pixel. Both our matrix calibration and two-point calibration are applied to our mid-wavelength infrared (MWIR) polarization imaging system with integrated microgrid polarimeters. Compared with two point calibration, our matrix calibration reduces non-uniformity by 30 40% under condition of flat-field data test with polarization. The ourdoor scene observation experiment indicates that our calibration can effectively reduce polarization non-uniformity and improve the image quality of our MWIR polarization imaging system.

Deployable Crew Quarters

NASA Technical Reports Server (NTRS)

Izenson, Michael G.; Chen, Weibo

2008-01-01

The deployable crew quarters (DCQ) have been designed for the International Space Station (ISS). Each DCQ would be a relatively inexpensive, deployable boxlike structure that is designed to fit in a rack bay. It is to be occupied by one crewmember to provide privacy and sleeping functions for the crew. A DCQ comprises mostly hard panels, made of a lightweight honeycomb or matrix/fiber material, attached to each other by cloth hinges. Both faces of each panel are covered with a layer of Nomex cloth and noise-suppression material to provide noise isolation from ISS. On Earth, the unit is folded flat and attached to a rigid pallet for transport to the ISS. On the ISS, crewmembers unfold the unit and install it in place, attaching it to ISS structural members by use of soft cords (which also help to isolate noise and vibration). A few hard pieces of equipment (principally, a ventilator and a smoke detector) are shipped separately and installed in the DCQ unit by use of a system of holes, slots, and quarter-turn fasteners. Full-scale tests showed that the time required to install a DCQ unit amounts to tens of minutes. The basic DCQ design could be adapted to terrestrial applications to satisfy requirements for rapid deployable emergency shelters that would be lightweight, portable, and quickly erected. The Temporary Early Sleep Station (TeSS) currently on-orbit is a spin-off of the DCQ.

Advances in infrastructure support for flat panel display manufacturing

NASA Astrophysics Data System (ADS)

Bardsley, James N.; Ciesinski, Michael F.; Pinnel, M. Robert

1997-07-01

The success of the US display industry, both in providing high-performance displays for the US Department of Defense at reasonable cost and in capturing a significant share of the global civilian market, depends on maintaining technological leadership and on building efficient manufacturing capabilities. The US Display Consortium (USDC) was set up in 1993 by the US Government and private industry to guide the development of the infrastructure needed to support the manufacturing of flat panel displays. This mainly involves the supply of equipment and materials, but also includes the formation of partnerships and the training of a skilled labor force. Examples are given of successful development projects, some involving USDC participation, others through independent efforts of its member companies. These examples show that US-based companies can achieve leadership positions in this young and rapidly growing global market.

Carbon Nanotube Thin Film Transistors for Flat Panel Display Application.

PubMed

Liang, Xuelei; Xia, Jiye; Dong, Guodong; Tian, Boyuan; Peng, Lianmao

2016-12-01

Carbon nanotubes (CNTs) are promising materials for both high performance transistors for high speed computing and thin film transistors for macroelectronics, which can provide more functions at low cost. Among macroelectronics applications, carbon nanotube thin film transistors (CNT-TFT) are expected to be used soon for backplanes in flat panel displays (FPDs) due to their superior performance. In this paper, we review the challenges of CNT-TFT technology for FPD applications. The device performance of state-of-the-art CNT-TFTs are compared with the requirements of TFTs for FPDs. Compatibility of the fabrication processes of CNT-TFTs and current TFT technologies are critically examined. Though CNT-TFT technology is not yet ready for backplane production line of FPDs, the challenges can be overcome by close collaboration between research institutes and FPD manufacturers in the short term.

Can Integrated Micro-Optical Concentrator Technology Revolutionize Flat-Plate Photovoltaic Solar Energy Harvesting?

NASA Astrophysics Data System (ADS)

Haney, Michael W.

2015-12-01

The economies-of-scale and enhanced performance of integrated micro-technologies have repeatedly delivered disruptive market impact. Examples range from microelectronics to displays to lighting. However, integrated micro-scale technologies have yet to be applied in a transformational way to solar photovoltaic panels. The recently announced Micro-scale Optimized Solar-cell Arrays with Integrated Concentration (MOSAIC) program aims to create a new paradigm in solar photovoltaic panel technology based on the incorporation of micro-concentrating photo-voltaic (μ-CPV) cells. As depicted in Figure 1, MOSAIC will integrate arrays of micro-optical concentrating elements and micro-scale PV elements to achieve the same aggregated collection area and high conversion efficiency of a conventional (i.e., macro-scale) CPV approach, but with the low profile and mass, and hopefully cost, of a conventional non-concentrated PV panel. The reduced size and weight, and enhanced wiring complexity, of the MOSAIC approach provide the opportunity to access the high-performance/low-cost region between the conventional CPV and flat-plate (1-sun) PV domains shown in Figure 2. Accessing this portion of the graph in Figure 2 will expand the geographic and market reach of flat-plate PV. This talk reviews the motivation and goals for the MOSAIC program. The diversity of the technical approaches to micro-concentration, embedded solar tracking, and hybrid direct/diffuse solar resource collection found in the MOSAIC portfolio of projects will also be highlighted.

Theoretical and Monte Carlo optimization of a stacked three-layer flat-panel x-ray imager for applications in multi-spectral diagnostic medical imaging

NASA Astrophysics Data System (ADS)

Lopez Maurino, Sebastian; Badano, Aldo; Cunningham, Ian A.; Karim, Karim S.

2016-03-01

We propose a new design of a stacked three-layer flat-panel x-ray detector for dual-energy (DE) imaging. Each layer consists of its own scintillator of individual thickness and an underlying thin-film-transistor-based flat-panel. Three images are obtained simultaneously in the detector during the same x-ray exposure, thereby eliminating any motion artifacts. The detector operation is two-fold: a conventional radiography image can be obtained by combining all three layers' images, while a DE subtraction image can be obtained from the front and back layers' images, where the middle layer acts as a mid-filter that helps achieve spectral separation. We proceed to optimize the detector parameters for two sample imaging tasks that could particularly benefit from this new detector by obtaining the best possible signal to noise ratio per root entrance exposure using well-established theoretical models adapted to fit our new design. These results are compared to a conventional DE temporal subtraction detector and a single-shot DE subtraction detector with a copper mid-filter, both of which underwent the same theoretical optimization. The findings are then validated using advanced Monte Carlo simulations for all optimized detector setups. Given the performance expected from initial results and the recent decrease in price for digital x-ray detectors, the simplicity of the three-layer stacked imager approach appears promising to usher in a new generation of multi-spectral digital x-ray diagnostics.

High-quality 3D correction of ring and radiant artifacts in flat panel detector-based cone beam volume CT imaging

NASA Astrophysics Data System (ADS)

Abu Anas, Emran Mohammad; Kim, Jae Gon; Lee, Soo Yeol; Kamrul Hasan, Md

2011-10-01

The use of an x-ray flat panel detector is increasingly becoming popular in 3D cone beam volume CT machines. Due to the deficient semiconductor array manufacturing process, the cone beam projection data are often corrupted by different types of abnormalities, which cause severe ring and radiant artifacts in a cone beam reconstruction image, and as a result, the diagnostic image quality is degraded. In this paper, a novel technique is presented for the correction of error in the 2D cone beam projections due to abnormalities often observed in 2D x-ray flat panel detectors. Template images are derived from the responses of the detector pixels using their statistical properties and then an effective non-causal derivative-based detection algorithm in 2D space is presented for the detection of defective and mis-calibrated detector elements separately. An image inpainting-based 3D correction scheme is proposed for the estimation of responses of defective detector elements, and the responses of the mis-calibrated detector elements are corrected using the normalization technique. For real-time implementation, a simplification of the proposed off-line method is also suggested. Finally, the proposed algorithms are tested using different real cone beam volume CT images and the experimental results demonstrate that the proposed methods can effectively remove ring and radiant artifacts from cone beam volume CT images compared to other reported techniques in the literature.

Metal artifact reduction for flat panel detector intravenous CT angiography in patients with intracranial metallic implants after endovascular and surgical treatment

PubMed Central

Pjontek, Rastislav; Önenköprülü, Belgin; Scholz, Bernhard; Kyriakou, Yiannis; Schubert, Gerrit A; Othman, Ahmed; Wiesmann, Martin; Brockmann, Marc A

2016-01-01

Background Flat panel detector CT angiography with intravenous contrast agent injection (IV CTA) allows high-resolution imaging of cerebrovascular structures. Artifacts caused by metallic implants like platinum coils or clips lead to degradation of image quality and are a significant problem. Objective To evaluate the influence of a prototype metal artifact reduction (MAR) algorithm on image quality in patients with intracranial metallic implants. Methods Flat panel detector CT after intravenous application of 80 mL contrast agent was performed with an angiography system (Artis zee; Siemens, Forchheim, Germany) using a 20 s rotation protocol (200° rotation angle, 20 s acquisition time, 496 projections). The data before and after MAR of 26 patients with a total of 34 implants (coils, clips, stents) were independently evaluated by two blinded neuroradiologists. Results MAR improved the assessability of the brain parenchyma and small vessels (diameter <1 mm) in the neighborhood of metallic implants and at a distance of 6 cm (p<0.001 each, Wilcoxon test). Furthermore, MAR significantly improved the assessability of parent vessel patency and potential aneurysm remnants (p<0.005 each, McNemar test). MAR, however, did not improve assessability of stented vessels. Conclusions When an intravenous contrast protocol is used, MAR significantly ameliorates the assessability of brain parenchyma, vessels, and treated aneurysms in patients with intracranial coils or clips. PMID:26346458

Flat panel detectors--closing the (digital) gap in chest and skeletal radiology.

PubMed

Reiff, K J

1999-08-01

In the radiological department today the majority of all X-ray procedures on chest and skeletal radiography is performed with classical film-screen-systems. Using digital luminescence radiography (DLR or CR, which stands for Computed Radiography) as a technique has shown a way to replace this 100-year-old procedure of doing general radiography work by acquiring the X-rays digitally via phosphor screens, but this approach has faced criticism from lots of radiologists world wide and therefore has not been widely accepted except in the intensive care environment. A new technology is now rising based on the use of so called flat panel X-ray (FD) detectors. Semi-conducting material detects the X-rays in digital form directly and creates an instantaneous image for display, distribution and diagnosis. This ability combined with a large field of view and compared to existing methods--excellent detective quantum efficiency represents a revolutionary step for chest and skeletal radiography and will put basic X-ray-work back into the focus of radiological solutions. This paper will explain the basic technology of flat panel detectors, possible system solutions based on this new technology, aspects of the user interface influencing the system utilization and versatility as well as the possibility to redefine the patient examination process for chest and skeletal radiography. Furthermore the author discusses limitations for the first released systems, upgrades for the installed base and possible scenarios for the future, e.g. fluoroscopy or angiography application.

Investigation of the effect of tablet surface area/volume on drug release from hydroxypropylmethylcellulose controlled-release matrix tablets.

PubMed

Reynolds, Thomas D; Mitchell, Shawn A; Balwinski, Karen M

2002-04-01

The purpose of this study was to investigate the influence of tablet surface area/volume (SA/Vol) on drug release from controlled-release matrix tablets containing hydroxypropylmethylcellulose (HPMC). Soluble drugs (promethazine HCl, diphenhydramine HCl, and propranolol HCl) were utilized in this study to give predominantly diffusion-controlled release. Drug release from HPMC matrix tablets with similar values of SA/Vol was comparable within the same tablet shape (i.e., flat-faced round tablets) and among different shapes (i.e., oval, round concave, flat-faced beveled-edge, and flat-faced round tablets). Tablets having the same surface area but different SA/Vol values did not result in similar drug release; tablets with larger SA/Vol values hadfaster release profiles. Utility of SA/Vol to affect drug release was demonstrated by changing drug doses, and altering tablet shape to adjust SA/Vol. When SA/Vol was held constant, similar release profiles were obtained with f2 metric values greater than 70. Thus, surface area/volume is one of the key variables in controlling drug release from HPMC matrix tablets. Proper use of this variable has practical application by formulators who may need to duplicate drug release profiles from tablets of different sizes and different shapes.

Initial steps toward the realization of large area arrays of single photon counting pixels based on polycrystalline silicon TFTs

NASA Astrophysics Data System (ADS)

Liang, Albert K.; Koniczek, Martin; Antonuk, Larry E.; El-Mohri, Youcef; Zhao, Qihua; Jiang, Hao; Street, Robert A.; Lu, Jeng Ping

2014-03-01

The thin-film semiconductor processing methods that enabled creation of inexpensive liquid crystal displays based on amorphous silicon transistors for cell phones and televisions, as well as desktop, laptop and mobile computers, also facilitated the development of devices that have become ubiquitous in medical x-ray imaging environments. These devices, called active matrix flat-panel imagers (AMFPIs), measure the integrated signal generated by incident X rays and offer detection areas as large as ~43×43 cm2. In recent years, there has been growing interest in medical x-ray imagers that record information from X ray photons on an individual basis. However, such photon counting devices have generally been based on crystalline silicon, a material not inherently suited to the cost-effective manufacture of monolithic devices of a size comparable to that of AMFPIs. Motivated by these considerations, we have developed an initial set of small area prototype arrays using thin-film processing methods and polycrystalline silicon transistors. These prototypes were developed in the spirit of exploring the possibility of creating large area arrays offering single photon counting capabilities and, to our knowledge, are the first photon counting arrays fabricated using thin film techniques. In this paper, the architecture of the prototype pixels is presented and considerations that influenced the design of the pixel circuits, including amplifier noise, TFT performance variations, and minimum feature size, are discussed.

Purging of a multilayer insulation with dacron tuft spacer by gas diffusion

NASA Technical Reports Server (NTRS)

Sumner, I. E.; Fisk, W. J.

1976-01-01

The time and purge gas usage required to purge a multilayer insulation (MLI) panel with gaseous helium by means of gas diffusion to obtain a condensable gas (nitrogen) concentration of less than 1 percent within the panel are stipulated. Two different, flat, rectangular MLI panels, one incorporating a butt joint, were constructed of of 11 double-aluminized Mylar (DAM) radiation shields separated by Dacron tuft spacers. The DAM/Dacron tuft concept is known commercially as Superfloc. The nitrogen gas concentration as a function of time within the MLI panel could be adequately predicted by using a simple, one dimensional gas diffusion model in which the boundary conditions at the edge of the MLI panel were time dependent. The time and purge gas usage required to achieve 1 percent nitrogen gas concentration within the MLI panel varied from 208 to 86 minutes and 34.1 to 56.5 MLI panel purge volumes, respectively, for gaseous helium purge rates from 10 to 40 MLI panel volumes per hour.

Thermo-elastoviscoplastic snapthrough behavior of cylindrical panels

NASA Technical Reports Server (NTRS)

Song, Y.; Simitses, G. J.

1992-01-01

The thermo-elastoviscoplastic snapthrough behavior of simply supported cylindrical panels is investigated. The analysis is based on nonlinear kinematic relations and nonlinear rate-dependent unified constitutive equations which include both Bodner-Partom's and Walker's material models. A finite element approach is employed to predict the inelastic buckling behavior. Numerical examples are given to demonstrate the effects of several parameters which include the temperature, thickness and flatness of the panel. Comparisons of buckling responses between Bodner-Partom's model and Walker's model are given. The creep buckling behavior, as an example of time-dependent inelastic deformation, is also presented.

Nondestructive evaluation and characterization of damage and repair to continuous-fiber ceramic composite panels.

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

Sun, J. G.; Petrak, D. R.; Pillai, T. A. K.

1998-04-01

Continuous fiber ceramic matrix composites are currently being developed for a variety of high-temperature applications. Because of the high costs of making these components, minor damage incurred during manufacturing or operation must be rewired in order to extend the life of the components. In this study, five ceramic-grade Nicalon{trademark} fiber/SiNC-matrix composite panels were intentionally damaged with a pendulum-type impactor during an impact test. The damaged panels were then repaired at Dow Corning Corporation. Three nondestructive evaluation (NDE) methods were used to study the characteristics of the panels after the damage and again after the panels were repaired. The NDE methodsmore » were X-ray radiography, infrared thermal imaging, and air-coupled ultrasound. The results showed that the impact test induced various types of damage in the panels. The NDE data that were obtained by the three NDE methods were correlated with each other.« less

In-Plane Cracking Behavior and Ultimate Strength for 2D Woven and Braided Melt-Infiltrated SiC/SiC Composites Tensile Loaded in Off-Axis Fiber Directions

NASA Technical Reports Server (NTRS)

Morscher, Gregory N.; Yun, Hee Mann; DiCarlo, James A.

2007-01-01

The tensile mechanical properties of ceramic matrix composites (CMC) in directions off the primary axes of the reinforcing fibers are important for architectural design of CMC components that are subjected to multi-axial stress states. In this study, 2D-woven melt-infiltrated (MI) SiC/SiC composite panels with balanced fiber content in the 0 degree and 90 degree directions were tensile loaded in-plane in the 0 degree direction and at 45 degree to this direction. In addition, a 2D triaxially-braided MI composite panel with balanced fiber content in the plus or minus 67 degree bias directions and reduced fiber content in the axial direction was tensile loaded perpendicular to the axial direction tows (i.e., 23 degrees from the bias fibers). Stress-strain behavior, acoustic emission, and optical microscopy were used to quantify stress-dependent matrix cracking and ultimate strength in the panels. It was observed that both off-axis loaded panels displayed higher composite onset stresses for through-thickness matrix cracking than the 2D-woven 0/90 panels loaded in the primary 0 degree direction. These improvements for off-axis cracking strength can in part be attributed to higher effective fiber fractions in the loading direction, which in turn reduces internal stresses on critical matrix flaws for a given composite stress. Also for the 0/90 panel loaded in the 45 degree direction, an improved distribution of matrix flaws existed due to the absence of fiber tows perpendicular to the loading direction. In addition, for the +67/0/-67 braided panel, the axial tows perpendicular to the loading direction were not only low in volume fraction, but were also were well separated from one another. Both off-axis oriented panels also showed relatively good ultimate tensile strength when compared to other off-axis oriented composites in the literature, both on an absolute strength basis as well as when normalized by the average fiber strength within the composites. Initial implications are discussed for constituent and architecture design to improve the directional cracking of SiC/SiC CMC components with MI matrices.

Solar hot water system installed at Las Vegas, Nevada

NASA Technical Reports Server (NTRS)

1981-01-01

A solar energy hot water system installed in a motor inn at Las Vegas, Nevada is described. The inn is a three story building with a flat roof for installation of the solar panels. The system consists of 1,200 square feet of liquid flat plate collectors, a 2,500 gallon insulated vertical steel storage tank, two heat exchangers, and pumps and controls. The system was designed to supply approximately 74 percent of the total hot water load.

Nondestructive evaluation of ceramic and metal matrix composites for NASA's HITEMP and enabling propulsion materials programs

NASA Technical Reports Server (NTRS)

Generazio, Edward R.

1992-01-01

In a preliminary study, ultrasonic, x-ray opaque, and fluorescent dye penetrants techniques were used to evaluate and characterize ceramic and metal matrix composites. Techniques are highlighted for identifying porosity, fiber alignment, fiber uniformity, matrix cracks, fiber fractures, unbonds or disbonds between laminae, and fiber-to-matrix bond variations. The nondestructive evaluations (NDE) were performed during processing and after thermomechanical testing. Specific examples are given for Si3N4/SiC (SCS-6 fiber), FeCrAlY/Al2O3 fibers, Ti-15-3/SiC (SCS-6 fiber) materials, and Si3N4/SiC (SCS-6 fiber) actively cooled panel components. Results of this study indicate that the choice of the NDE tools to be used can be optimized to yield a faithful and accurate evaluation of advanced composites.

Effect of soiling in CPV systems

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

Vivar, M.; Herrero, R.; Anton, I.

2010-07-15

The effect of soiling in flat PV modules has been already studied, causing a reduction of the electrical output of 4% on average. For CPV's, as far as soiling produces light scattering at the optical collector surface, the scattered rays should be definitively lost because they cannot be focused onto the receivers again. While the theoretical study becomes difficult because soiling is variable at different sites, it becomes easier to begin the monitoring of the real field performance of concentrators and then raise the following question: how much does the soiling affect to PV concentrators in comparison with flat panels?'more » The answers allow to predict the PV concentrator electrical performance and to establish a pattern of cleaning frequency. Some experiments have been conducted at the IES-UPM and CSES-ANU sites, consisting in linear reflective concentration systems, a point focus refractive concentrator and a flat module. All the systems have been measured when soiled and then after cleaning, achieving different increases of I{sub SC}. In general, results show that CPV systems are more sensitive to soiling than flat panels, accumulating losses in I{sub SC} of about 14% on average in three different tests conducted at IES-UPM and CSES-ANU test sites in Madrid (Spain) and Canberra (Australia). Some concentrators can reach losses up to 26% when the system is soiled for 4 months of exposure. (author)« less

SU-C-304-05: Use of Local Noise Power Spectrum and Wavelets in Comprehensive EPID Quality Assurance

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

Lee, S; Gopal, A; Yan, G

2015-06-15

Purpose: As EPIDs are increasingly used for IMRT QA and real-time treatment verification, comprehensive quality assurance (QA) of EPIDs becomes critical. Current QA with phantoms such as the Las Vegas and PIPSpro™ can fail in the early detection of EPID artifacts. Beyond image quality assessment, we propose a quantitative methodology using local noise power spectrum (NPS) to characterize image noise and wavelet transform to identify bad pixels and inter-subpanel flat-fielding artifacts. Methods: A total of 93 image sets including bar-pattern images and open exposure images were collected from four iViewGT a-Si EPID systems over three years. Quantitative metrics such asmore » modulation transform function (MTF), NPS and detective quantum efficiency (DQE) were computed for each image set. Local 2D NPS was calculated for each subpanel. A 1D NPS was obtained by radial averaging the 2D NPS and fitted to a power-law function. R-square and slope of the linear regression analysis were used for panel performance assessment. Haar wavelet transformation was employed to identify pixel defects and non-uniform gain correction across subpanels. Results: Overall image quality was assessed with DQE based on empirically derived area under curve (AUC) thresholds. Using linear regression analysis of 1D NPS, panels with acceptable flat fielding were indicated by r-square between 0.8 and 1, and slopes of −0.4 to −0.7. However, for panels requiring flat fielding recalibration, r-square values less than 0.8 and slopes from +0.2 to −0.4 were observed. The wavelet transform successfully identified pixel defects and inter-subpanel flat fielding artifacts. Standard QA with the Las Vegas and PIPSpro phantoms failed to detect these artifacts. Conclusion: The proposed QA methodology is promising for the early detection of imaging and dosimetric artifacts of EPIDs. Local NPS can accurately characterize the noise level within each subpanel, while the wavelet transforms can detect bad pixels and inter-subpanel flat fielding artifacts.« less

ARC-1976-AC76-0965

NASA Image and Video Library

1976-06-11

Artist: Rick Guidice Space Colonization - Bernal Sphere - The residential area is in the central sphere. Farming regions are in the 'tires.' Mirrors reflect sunlight into the habitat and farms. The large flat panels radiate away extra heat into space, and panels of solar cells provide electricity. Factories and docks for spaceships are at either end of the long central tube. (NOTE: art printed in Book 'Space Colony - Frontier of the 21st Century by Franklyn M. Branley)

Metal matrix composite structural panel construction

NASA Technical Reports Server (NTRS)

Mcwithey, R. R.; Royster, D. M. (Inventor); Bales, T. T.

1983-01-01

Lightweight capped honeycomb stiffeners for use in fabricating metal or metal/matrix exterior structural panels on aerospace type vehicles and the process for fabricating same are disclosed. The stiffener stringers are formed in sheets, cut to the desired width and length and brazed in spaced relationship to a skin with the honeycomb material serving directly as the required lightweight stiffeners and not requiring separate metal encasement for the exposed honeycomb cells.

RADIANCE PROCESS EVALUATION FOR PARTICLE REMOVAL

EPA Science Inventory

The microelectronics industry (wafer, flat panel displays, photomasks, and storage media) is transitioning to higher device densities and larger substrate formats. These changes will challenge standard cleaning methods and will require significant increases to the fabricator inf...

NIST display colorimeter calibration facility

NASA Astrophysics Data System (ADS)

Brown, Steven W.; Ohno, Yoshihiro

2003-07-01

A facility has been developed at the National Institute of Standards and Technology (NIST) to provide calibration services for color-measuring instruments to address the need for improving and certifying the measurement uncertainties of this type of instrument. While NIST has active programs in photometry, flat panel display metrology, and color and appearance measurements, these are the first services offered by NIST tailored to color-measuring instruments for displays. An overview of the facility, the calibration approach, and associated uncertainties are presented. Details of a new tunable colorimetric source and the development of new transfer standard instruments are discussed.

Multigrid Equation Solvers for Large Scale Nonlinear Finite Element Simulations

DTIC Science & Technology

1999-01-01

purpose of the second partitioning phase , on each SMP, is to minimize the communication within the SMP; even if a multi - threaded matrix vector product...8.7 Comparison of model with experimental data for send phase of matrix vector product on ne grid...140 8.4 Matrix vector product phase times : : : : : : : : : : : : : : : : : : : : : : : 145 9.1 Flat and

Driving platform for OLED lighting investigations

NASA Astrophysics Data System (ADS)

Vogel, Uwe; Elgner, Andreas; Kreye, Daniel; Amelung, Jörg; Scholles, Michael

2006-08-01

OLED technology may be excellently suitable for lighting applications by combining high efficiency, cost effective manufacturing and the use of low cost materials. Certain issues remain to be solved so far, including OLED brightness, color, lifetime, large area uniformity and encapsulation. Another aspect, that might be capable in addressing some of the mentioned issues, is OLED lighting electrical driving. We report on the design of a driving platform for OLED lighting test panels or substrates. It is intended for being a test environment for lighting substrates as well as demonstration/presentation environment. It is based on a 128-channel passive-matrix driver/controller ASIC OC2. Its key component is an MSP430-compatible 16-bit micro-controller core including embedded Flash memory (program), EEPROM (parameter), and RAM (data memory). A significant feature of the device is an electronic approach for improving the lifetime/uniformity behavior of connected OLED. The embedded micro-controller is the key to the high versatility of OC2, since by firmware modification it can be adapted to various applications and conditions. Here its application for an OLED lighting driving platform is presented. Major features of this platform are PC-control mode (via USB interface), stand-alone mode (no external control necessary, just power supply), on-board OLED panel parameter storage, flat geometry of OLED lighting panel carrier (board), AC and DC driving regimes, adjustable reverse voltage, dedicated user SW (PC/Windows-based), sub-tile patterning and single sub-tile control, combination of multiple channels for increasing driving current. This publication contains results of the project "High Brightness OLEDs for ICT & Next Generation Lighting Applications" (OLLA), funded by the European Commission.

Concepts for improving the damage tolerance of composite compression panels. [aircraft structures

NASA Technical Reports Server (NTRS)

Rhodes, M. D.; Williams, J. G.

1984-01-01

The residual strength of specimens with damage and the sensitivity to damage while subjected to an applied inplane compression load were determined for flatplate specimens and blade-stiffened panels. The results suggest that matrix materials that fail by delamination have the lowest damage tolerance capability. Alternate matrix materials or laminates which are transversely reinforced suppress the delamination mode of failure and change the failure mode to transverse shear crippling which occurs at a higher strain value. Several damage-tolerant blade-stiffened panel design concepts are evaluated. Structural efficiency studies conducted show only small mass penalties may result from incorporating these damage-tolerant features in panel design. The implication of test results on the design of aircraft structures was examined with respect to FAR requirements.

Modeling of trim panels in the energy finite element analysis

NASA Astrophysics Data System (ADS)

Moravaeji, Seyed-Javid

Modeling a trim panel is divided into finding the power exchange through two different paths: (i) the connection of the outer and inner panels (ii) through the layers directly. The vibrational power exchanged through the mounts is modeled as the connection of two parallel plates connected via a beam. Wave matrices representing plates and beams are derived separately; then a matrix method is proposed to solve for the wave amplitudes and hence the vibrational power exchange between the plates accordingly. A closed form formula for the case of connection of two identical plates is derived. For the power transmission loss directly through the layers, first transfer matrices representing layers made of different materials is considered. New matrices for a porous layer are derived. A method of finding the layered structure transfer matrix is proposed. It is concluded that in general a single isotropic layer cannot replace a structure accurately. Finally, on the basis of an equivalent transfer matrix, an optimization process for is proposed to replace the panel by a suitable set of layers.

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

Scheuermann, J; Howansky, A; Goldan, A

Purpose: We present the first active matrix flat panel imager (AMFPI) capable of producing x-ray quantum noise limited images at low doses by overcoming the electronic noise through signal amplification by photoconductive avalanche gain (gav). The indirect detector fabricated uses an optical sensing layer of amorphous selenium (a-Se) known as High-Gain Avalanche Rushing Photoconductor (HARP). The detector design is called Scintillator HARP (SHARP)-AMFPI. This is the first image sensor to utilize solid-state HARP technology. Methods: The detector’s electronic readout is a 24 × 30 cm{sup 2} array of thin film transistors (TFT) with a pixel pitch of 85 µm. Themore » HARP structure consists of a 15 µm layer of a-Se isolated from the high voltage (HV) and signal electrode by a 2 µm thick hole blocking layer and electron blocking layer, respectively, to reduce dark current. A 150 µm thick structured CsI scintillator with reflective backing and a fiber optic faceplate (FOP) was coupled to the semi-transparent HV bias electrode of the HARP structure. Images were acquired using a 30 kVp Mo/Mo spectrum typically used in mammography. Results: Optical sensitivity measurements demonstrate that gav = 76 ± 5 can be achieved over the entire active area of the detector. At a constant dose to the detector of 6.67 µGy, image quality increases with gav until the effective electronic noise is negligible. Quantum noise limited images can be obtained with doses as low as 0.18 µGy. Conclusion: We demonstrate the feasibility of utilizing avalanche gain to overcome electronic noise. The indirect detector fabricated is the first solid-state imaging sensor to use HARP, and the largest active area HARP sensor to date. Our future work is to improve charge transport within the HARP structure and utilize a transparent HV electrode.« less

Noise performance limits of advanced x-ray imagers employing poly-Si-based active pixel architectures

NASA Astrophysics Data System (ADS)

Koniczek, Martin; El-Mohri, Youcef; Antonuk, Larry E.; Liang, Albert; Zhao, Qihua; Jiang, Hao

2011-03-01

A decade after the clinical introduction of active matrix, flat-panel imagers (AMFPIs), the performance of this technology continues to be limited by the relatively large additive electronic noise of these systems - resulting in significant loss of detective quantum efficiency (DQE) under conditions of low exposure or high spatial frequencies. An increasingly promising approach for overcoming such limitations involves the incorporation of in-pixel amplification circuits, referred to as active pixel architectures (AP) - based on low-temperature polycrystalline silicon (poly-Si) thin-film transistors (TFTs). In this study, a methodology for theoretically examining the limiting noise and DQE performance of circuits employing 1-stage in-pixel amplification is presented. This methodology involves sophisticated SPICE circuit simulations along with cascaded systems modeling. In these simulations, a device model based on the RPI poly-Si TFT model is used with additional controlled current sources corresponding to thermal and flicker (1/f) noise. From measurements of transfer and output characteristics (as well as current noise densities) performed upon individual, representative, poly-Si TFTs test devices, model parameters suitable for these simulations are extracted. The input stimuli and operating-point-dependent scaling of the current sources are derived from the measured current noise densities (for flicker noise), or from fundamental equations (for thermal noise). Noise parameters obtained from the simulations, along with other parametric information, is input to a cascaded systems model of an AP imager design to provide estimates of DQE performance. In this paper, this method of combining circuit simulations and cascaded systems analysis to predict the lower limits on additive noise (and upper limits on DQE) for large area AP imagers with signal levels representative of those generated at fluoroscopic exposures is described, and initial results are reported.

NASTRAN DMAP Fuzzy Structures Analysis: Summary of Research

NASA Technical Reports Server (NTRS)

Sparrow, Victor W.

2001-01-01

The main proposed tasks of Cooperative Agreement NCC1-382 were: (1) developing MSC/NASTRAN DMAP language scripts to implement the Soize fuzzy structures approach for modeling the dynamics of complex structures; (2) benchmarking the results of the new code to those for a cantilevered beam in the literature; and (3) testing and validating the new code by comparing the fuzzy structures results to NASA Langley experimental and conventional finite element results for two model test structures representative of aircraft fuselage sidewall construction: (A) a small aluminum test panel (SLP, single longeron panel) with a single longitudinal stringer attached with bolts; and (B) a 47 by 72 inch flat aluminum fuselage panel (AFP, aluminum fuselage panel) including six longitudinal stringers and four frame stiffeners attached with rivets.

Finite Element Analysis of the Random Response Suppression of Composite Panels at Elevated Temperatures using Shape Memory Alloy Fibers

NASA Technical Reports Server (NTRS)

Turner, Travis L.; Zhong, Z. W.; Mei, Chuh

1994-01-01

A feasibility study on the use of shape memory alloys (SMA) for suppression of the random response of composite panels due to acoustic loads at elevated temperatures is presented. The constitutive relations for a composite lamina with embedded SMA fibers are developed. The finite element governing equations and the solution procedures for a composite plate subjected to combined acoustic and thermal loads are presented. Solutions include: 1) Critical buckling temperature; 2) Flat panel random response; 3) Thermal postbuckling deflection; 4) Random response of a thermally buckled panel. The preliminary results demonstrate that the SMA fibers can completely eliminate the thermal postbuckling deflection and significantly reduce the random response at elevated temperatures.

Indirect-detection single-photon-counting x-ray detector for breast tomosynthesis

NASA Astrophysics Data System (ADS)

Jiang, Hao; Kaercher, Joerg; Durst, Roger

2016-03-01

X-ray mammography is a crucial screening tool for early identification of breast cancer. However, the overlap of anatomical features present in projection images often complicates the task of correctly identifying suspicious masses. As a result, there has been increasing interest in acquisition of volumetric information through digital breast tomosynthesis (DBT) which, compared to mammography, offers the advantage of depth information. Since DBT requires acquisition of many projection images, it is desirable that the noise in each projection image be dominated by the statistical noise of the incident x-ray quanta and not by the additive noise of the imaging system (referred to as quantum-limited imaging) and that the cumulative dose be as low as possible (e.g., no more than for a mammogram). Unfortunately, the electronic noise (~2000 electrons) present in current DBT systems based on active matrix, flat-panel imagers (AMFPIs) is still relatively high compared with modest x-ray gain of the a-Se and CsI:Tl x-ray converters often used. To overcome the modest signal-to-noise ratio (SNR) limitations of current DBT systems, we have developed a large-area x-ray imaging detector with the combination of an extremely low noise (~20 electrons) active-pixel CMOS and a specially designed high resolution scintillator. The high sensitivity and low noise of such system provides better SNR by at least an order of magnitude than current state-of-art AMFPI systems and enables x-ray indirect-detection single photon counting (SPC) at mammographic energies with the potential of dose reduction.

Development of CFRP mirrors for space telescopes

NASA Astrophysics Data System (ADS)

Utsunomiya, Shin; Kamiya, Tomohiro; Shimizu, Ryuzo

2013-09-01

CFRP (Caron fiber reinforced plastics) have superior properties of high specific elasticity and low thermal expansion for satellite telescope structures. However, difficulties to achieve required surface accuracy and to ensure stability in orbit have discouraged CFRP application as main mirrors. We have developed ultra-light weight and high precision CFRP mirrors of sandwich structures composed of CFRP skins and CFRP cores using a replica technique. Shape accuracy of the demonstrated mirrors of 150 mm in diameter was 0.8 μm RMS (Root Mean Square) and surface roughness was 5 nm RMS as fabricated. Further optimization of fabrication process conditions to improve surface accuracy was studied using flat sandwich panels. Then surface accuracy of the flat CFRP sandwich panels of 150 mm square was improved to flatness of 0.2 μm RMS with surface roughness of 6 nm RMS. The surface accuracy vs. size of trial models indicated high possibility of fabrication of over 1m size mirrors with surface accuracy of 1μm. Feasibility of CFRP mirrors for low temperature applications was examined for JASMINE project as an example. Stability of surface accuracy of CFRP mirrors against temperature and moisture was discussed.

Promoting Cartilage Stem Cell Activity to Improve Recovery from Joint Fracture

DTIC Science & Technology

2012-09-01

were obtained after slaughter from a local abattoir (Bud’s Custom Meats , Riverside, IA). Osteochondral explants were prepared by manually sawing an...from the superficial 1/3 or lower 2/3 of the matrix were plated in 150-mm culture dishes and incubated for 10 days. A custom-fabricated device was...Richardson’s stain. The dishes were scanned on a flat bed scanner (300 dpi) and the number of colonies and colony diameters were measured using

Automated array assembly

NASA Technical Reports Server (NTRS)

Daiello, R. V.

1977-01-01

A general technology assessment and manufacturing cost analysis was presented. A near-term (1982) factory design is described, and the results of an experimental production study for the large-scale production of flat-panel silicon and solar-cell arrays are detailed.

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.

31. INTERIOR VIEW TO THE SOUTHWEST OF A THIRD CONTROL ...

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

31. INTERIOR VIEW TO THE SOUTHWEST OF A THIRD CONTROL PANEL IN ROOM 105, THE CONTROL ROOM. - Nevada Test Site, Pluto Facility, Disassembly Building, Area 26, Wahmonie Flats, Cane Spring Road, Mercury, Nye County, NV

30. INTERIOR VIEW TO THE WEST OF A SECOND CONTROL ...

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

30. INTERIOR VIEW TO THE WEST OF A SECOND CONTROL PANEL IN ROOM 105, THE CONTROL ROOM. - Nevada Test Site, Pluto Facility, Disassembly Building, Area 26, Wahmonie Flats, Cane Spring Road, Mercury, Nye County, NV

Impact and Penetration of Thin Aluminum 2024 Flat Panels at Oblique Angles of Incidence

NASA Technical Reports Server (NTRS)

Ruggeri, Charles R.; Revilock, Duane M.; Pereira, J. Michael; Emmerling, William; Queitzsch, Gilbert K., Jr.

2015-01-01

The U.S. Federal Aviation Administration (FAA) and the National Aeronautics and Space Administration (NASA) are actively involved in improving the predictive capabilities of transient finite element computational methods for application to safety issues involving unintended impacts on aircraft and aircraft engine structures. One aspect of this work involves the development of an improved deformation and failure model for metallic materials, known as the Tabulated Johnson-Cook model, or MAT224, which has been implemented in the LS-DYNA commercial transient finite element analysis code (LSTC Corp., Livermore, CA) (Ref. 1). In this model the yield stress is a function of strain, strain rate and temperature and the plastic failure strain is a function of the state of stress, temperature and strain rate. The failure criterion is based on the accumulation of plastic strain in an element. The model also incorporates a regularization scheme to account for the dependency of plastic failure strain on mesh size. For a given material the model requires a significant amount of testing to determine the yield stress and failure strain as a function of the three-dimensional state of stress, strain rate and temperature. In addition, experiments are required to validate the model. Currently the model has been developed for Aluminum 2024 and validated against a series of ballistic impact tests on flat plates of various thicknesses (Refs. 1 to 3). Full development of the model for Titanium 6Al-4V is being completed, and mechanical testing for Inconel 718 has begun. The validation testing for the models involves ballistic impact tests using cylindrical projectiles impacting flat plates at a normal incidence (Ref. 2). By varying the thickness of the plates, different stress states and resulting failure modes are induced, providing a range of conditions over which the model can be validated. The objective of the study reported here was to provide experimental data to evaluate the model under more extreme conditions, using a projectile with a more complex shape and sharp contacts, impacting flat panels at oblique angles of incidence.

On-demand stereoscopic 3D displays for avionic and military applications

NASA Astrophysics Data System (ADS)

Sarma, Kalluri; Lu, Kanghua; Larson, Brent; Schmidt, John; Cupero, Frank

2010-04-01

High speed AM LCD flat panels are evaluated for use in Field Sequential Stereoscopic (FSS) 3D displays for military and avionic applications. A 120 Hz AM LCD is used in field-sequential mode for constructing eyewear-based as well as autostereoscopic 3D display demonstrators for test and evaluation. The COTS eyewear-based system uses shutter glasses to control left-eye/right-eye images. The autostereoscopic system uses a custom backlight to generate illuminating pupils for left and right eyes. It is driven in synchronization with the images on the LCD. Both displays provide 3D effect in full-color and full-resolution in the AM LCD flat panel. We have realized luminance greater than 200 fL in 3D mode with the autostereoscopic system for sunlight readability. The characterization results and performance attributes of both systems are described.

A Rotatable Quality Control Phantom for Evaluating the Performance of Flat Panel Detectors in Imaging Moving Objects.

PubMed

Haga, Yoshihiro; Chida, Koichi; Inaba, Yohei; Kaga, Yuji; Meguro, Taiichiro; Zuguchi, Masayuki

2016-02-01

As the use of diagnostic X-ray equipment with flat panel detectors (FPDs) has increased, so has the importance of proper management of FPD systems. To ensure quality control (QC) of FPD system, an easy method for evaluating FPD imaging performance for both stationary and moving objects is required. Until now, simple rotatable QC phantoms have not been available for the easy evaluation of the performance (spatial resolution and dynamic range) of FPD in imaging moving objects. We developed a QC phantom for this purpose. It consists of three thicknesses of copper and a rotatable test pattern of piano wires of various diameters. Initial tests confirmed its stable performance. Our moving phantom is very useful for QC of FPD images of moving objects because it enables visual evaluation of image performance (spatial resolution and dynamic range) easily.

Monitoring of experimental rat lung transplants by high-resolution flat-panel volumetric computer tomography (fpVCT).

PubMed

Greschus, Susanne; Kuchenbuch, Tim; Plötz, Christian; Obert, Martin; Traupe, Horst; Padberg, Winfried; Grau, Veronika; Hirschburger, Markus

2009-01-01

Noninvasive assessment of experimental lung transplants with high resolution would be favorable to exclude technical failure and to follow up graft outcome in the living animal. Here we describe a flat-panel Volumetric Computed Tomography (fpVCT) technique using a prototype scanner. Lung transplantation was performed in allogeneic as well as in corresponding syngeneic rat strain combinations. At different time points post-transplantation, fpVCT was performed. Lung transplants can be visualized in the living rat with high-spatial resolution. FpVCT allows a detailed analysis of the lung and the bronchi. Infiltrates developing during rejection episodes can be diagnosed and follow-up studies can easily be performed. With fpVCT it is possible to control the technical success of the surgical procedure. Graft rejection can be visualized individually in the living animal noninvasively, which is highly advantageous for studying the pathogenesis of chronic rejection or to monitor new therapies.

Process for producing Ti-Cr-Al-O thin film resistors

DOEpatents

Jankowski, Alan F.; Schmid, Anthony P.

2001-01-01

Thin films of Ti-Cr-Al-O are used as a resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O.sub.2. Resistivity values from 10.sup.4 to 10.sup.10 Ohm-cm have been measured for Ti-Cr-Al-O film <1 .mu.m thick. The film resistivity can be discretely selected through control of the target composition and the deposition parameters. The application of Ti-Cr-Al-O as a thin film resistor has been found to be thermodynamically stable, unlike other metal-oxide films. The Ti-Cr-Al-O film can be used as a vertical or lateral resistor, for example, as a layer beneath a field emission cathode in a flat panel display; or used to control surface emissivity, for example, as a coating on an insulating material such as vertical wall supports in flat panel displays.

TI--CR--AL--O thin film resistors

DOEpatents

Jankowski, Alan F.; Schmid, Anthony P.

2000-01-01

Thin films of Ti--Cr--Al--O are used as a resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O.sub.2. Resistivity values from 10.sup.4 to 10.sup.10 Ohm-cm have been measured for Ti--Cr--Al--O film <1 .mu.m thick. The film resistivity can be discretely selected through control of the target composition and the deposition parameters. The application of Ti--Cr--Al--O as a thin film resistor has been found to be thermodynamically stable, unlike other metal-oxide films. The Ti--Cr--Al--O film can be used as a vertical or lateral resistor, for example, as a layer beneath a field emission cathode in a flat panel display; or used to control surface emissivity, for example, as a coating on an insulating material such as vertical wall supports in flat panel displays.

A large flat panel multifunction display for military and space applications

NASA Astrophysics Data System (ADS)

Pruitt, James S.

1992-09-01

A flat panel multifunction display (MFD) that offers the size and reliability benefits of liquid crystal display technology while achieving near-CRT display quality is presented. Display generation algorithms that provide exceptional display quality are being implemented in custom VLSI components to minimize MFD size. A high-performance processor converts user-specified display lists to graphics commands used by these components, resulting in high-speed updates of two-dimensional and three-dimensional images. The MFD uses the MIL-STD-1553B data bus for compatibility with virtually all avionics systems. The MFD can generate displays directly from display lists received from the MIL-STD-1553B bus. Complex formats can be stored in the MFD and displayed using parameters from the data bus. The MFD also accepts direct video input and performs special processing on this input to enhance image quality.

Development of flat-plate solar collectors for the heating and cooling of buildings

NASA Technical Reports Server (NTRS)

Ramsey, J. W.; Borzoni, J. T.; Holland, T. H.

1975-01-01

The relevant design parameters in the fabrication of a solar collector for heating liquids were examined. The objective was to design, fabricate, and test a low-cost, flat-plate solar collector with high collection efficiency, high durability, and requiring little maintenance. Computer-aided math models of the heat transfer processes in the collector assisted in the design. The preferred physical design parameters were determined from a heat transfer standpoint and the absorber panel configuration, the surface treatment of the absorber panel, the type and thickness of insulation, and the number, spacing and material of the covers were defined. Variations of this configuration were identified, prototypes built, and performance tests performed using a solar simulator. Simulated operation of the baseline collector configuration was combined with insolation data for a number of locations and compared with a predicted load to determine the degree of solar utilization.

Recent advances in flexible low power cholesteric LCDs

NASA Astrophysics Data System (ADS)

Khan, Asad; Shiyanovskaya, Irina; Montbach, Erica; Schneider, Tod; Nicholson, Forrest; Miller, Nick; Marhefka, Duane; Ernst, Todd; Doane, J. W.

2006-05-01

Bistable reflective cholesteric displays are a liquid crystal display technology developed to fill a market need for very low power displays. Their unique look, high reflectivity, bistability, and simple structure make them an ideal flat panel display choice for handheld or other portable devices where small lightweight batteries with long lifetimes are important. Applications ranging from low resolution large signs to ultra high resolution electronic books can utilize cholesteric displays to not only benefit from the numerous features, but also create enabling features that other flat panel display technologies cannot. Flexible displays are the focus of attention of numerous research groups and corporations worldwide. Cholesteric displays have been demonstrated to be highly amenable to flexible substrates. This paper will review recent advances in flexible cholesteric displays including both phase separation and emulsification approaches to encapsulation. Both approaches provide unique benefits to various aspects of manufacturability, processes, flexibility, and conformability.

Enhancement in lipid content of Chlorella sp. MJ 11/11 from the spent medium of thermophilic biohydrogen production process.

PubMed

Ghosh, Supratim; Roy, Shantonu; Das, Debabrata

2017-01-01

The present study investigates the effect of spent media of acetogenic dark fermentation for mixotrophic algal cultivation for biodiesel production. Mixotrophic growth conditions were optimized in culture flask (250mL) using Chlorella sp. MJ 11/11. Maximum lipid accumulation (58% w/w) was observed under light intensity, pH, nitrate and phosphate concentration of 100μmolm -2 s -1 , 7, 2.7mM and 1.8mM, respectively. Air lift (1.4L) and flat panel (1.4L) reactors were considered for algal cultivation. Air lift showed significant improvement in biomass and lipid production as compared to flat panel reactor. The results could help in development of sustainable technology involving acetogenic hydrogen production integrated with sequential mitigation of spent media by algal cultivation for improved energy recovery. Copyright © 2016 Elsevier Ltd. All rights reserved.

Study of noise reduction characteristics of double-wall panels

NASA Technical Reports Server (NTRS)

Navaneethan, R.; Quayle, B.; Stevenson, S.; Graham, M.

1983-01-01

The noise reduction characteristics of general aviation type, flat, double-wall structures were investigated. The experimental study was carried out on 20-by-20 inch panels with an exposed area of 18 by 18 inches. A frequency range from 20 to 5000 Hz was covered. The experimental results, in general, follow the expected trends. At low frequencies the double-wall structures are no better than the single-wall structures. However, for depths normally used in the general aviation industry, the double-wall panels are very attractive. The graphite-spoxy skin panels have higher noise reduction at very low frequencies ( 100 Hz) than the Kevlar skin panels. But the aluminum panels have higher noise reduction in the high frequency region, due to their greater mass. Use of fiberglass insulation is not effective in the low frequency region, and at times it is even negative. But the insulation is effective in the high-frequency region. The theoretical model for predicting the transmission loss of these multilayered panels is also discussed.

Study of noise reduction characteristics of double-wall panels

NASA Astrophysics Data System (ADS)

Navaneethan, R.; Quayle, B.; Stevenson, S.; Graham, M.

1983-05-01

The noise reduction characteristics of general aviation type, flat, double-wall structures were investigated. The experimental study was carried out on 20-by-20 inch panels with an exposed area of 18 by 18 inches. A frequency range from 20 to 5000 Hz was covered. The experimental results, in general, follow the expected trends. At low frequencies the double-wall structures are no better than the single-wall structures. However, for depths normally used in the general aviation industry, the double-wall panels are very attractive. The graphite-spoxy skin panels have higher noise reduction at very low frequencies ( 100 Hz) than the Kevlar skin panels. But the aluminum panels have higher noise reduction in the high frequency region, due to their greater mass. Use of fiberglass insulation is not effective in the low frequency region, and at times it is even negative. But the insulation is effective in the high-frequency region. The theoretical model for predicting the transmission loss of these multilayered panels is also discussed.

Design and Manufacture of Elastically Tailored Tow Placed Plates

NASA Technical Reports Server (NTRS)

Tatting, Brain F.; Guerdal, Zafer; Jegley, Dawn (Technical Monitor)

2002-01-01

Elastic stiffness tailoring of laminated composite panels by allowing the fibers to curve within the plane of the laminate is a relatively novel design concept that has been demonstrated to be both beneficial and practical. In particular, for structures with highly non-uniform stress states, such as the case of a flat panel with a central hole subjected to in-plane loading, the concept is likely to provide substantial improvements in load carrying capability. The objective of the present study is to determine the effectiveness of stiffness tailoring through the use of curvilinear fibers to reduce stress concentrations around the hole and improve the load carrying capability of panels with holes. In this study software was created that translates standard finite element models with traditional laminate definitions into ones that possess stacking sequences with curvilinear fiber paths that are directly manufacturable using an advanced tow placement machine. Preliminary designs for the manufacturing and testing phase were determined through rudimentary design studies for flat plates without holes under axial compression. These candidate designs were then analyzed using finite element models that accurately reflect the test conditions and geometries in order to select final designs for testing. A total of six large panels, measuring three feet by six feet, each of which are used to produce four specimens with or without holes, were fabricated and delivered to NASA for machining and testing.

Advanced composites structural concepts and materials technologies for primary aircraft structures: Structural response and failure analysis

NASA Technical Reports Server (NTRS)

Dorris, William J.; Hairr, John W.; Huang, Jui-Tien; Ingram, J. Edward; Shah, Bharat M.

1992-01-01

Non-linear analysis methods were adapted and incorporated in a finite element based DIAL code. These methods are necessary to evaluate the global response of a stiffened structure under combined in-plane and out-of-plane loading. These methods include the Arc Length method and target point analysis procedure. A new interface material model was implemented that can model elastic-plastic behavior of the bond adhesive. Direct application of this method is in skin/stiffener interface failure assessment. Addition of the AML (angle minus longitudinal or load) failure procedure and Hasin's failure criteria provides added capability in the failure predictions. Interactive Stiffened Panel Analysis modules were developed as interactive pre-and post-processors. Each module provides the means of performing self-initiated finite elements based analysis of primary structures such as a flat or curved stiffened panel; a corrugated flat sandwich panel; and a curved geodesic fuselage panel. This module brings finite element analysis into the design of composite structures without the requirement for the user to know much about the techniques and procedures needed to actually perform a finite element analysis from scratch. An interactive finite element code was developed to predict bolted joint strength considering material and geometrical non-linearity. The developed method conducts an ultimate strength failure analysis using a set of material degradation models.

Development of tailorable advanced blanket insulation for advanced space transportation systems

NASA Technical Reports Server (NTRS)

Calamito, Dominic P.

1987-01-01

Two items of Tailorable Advanced Blanket Insulation (TABI) for Advanced Space Transportation Systems were produced. The first consisted of flat panels made from integrally woven, 3-D fluted core having parallel fabric faces and connecting ribs of Nicalon silicon carbide yarns. The triangular cross section of the flutes were filled with mandrels of processed Q-Fiber Felt. Forty panels were prepared with only minimal problems, mostly resulting from the unavailability of insulation with the proper density. Rigidizing the fluted fabric prior to inserting the insulation reduced the production time. The procedures for producing the fabric, insulation mandrels, and TABI panels are described. The second item was an effort to determine the feasibility of producing contoured TABI shapes from gores cut from flat, insulated fluted core panels. Two gores of integrally woven fluted core and single ply fabric (ICAS) were insulated and joined into a large spherical shape employing a tadpole insulator at the mating edges. The fluted core segment of each ICAS consisted of an Astroquartz face fabric and Nicalon face and rib fabrics, while the single ply fabric segment was Nicalon. Further development will be required. The success of fabricating this assembly indicates that this concept may be feasible for certain types of space insulation requirements. The procedures developed for weaving the ICAS, joining the gores, and coating certain areas of the fabrics are presented.

Safety-related requirements for photovoltaic modules and arrays. Final report

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

Levins, A.

1984-03-01

Underwriters Laboratories has conducted a study to identify and develop safety requirements for photovoltaic module and panel designs and configurations for residential, intermediate, and large scale applications. Concepts for safety systems, where each system is a collection of subsystems which together address the total anticipated hazard situation, are described. Descriptions of hardware, and system usefulness and viability are included. This discussion of safety systems recognizes that there is little history on which to base the expected safety related performance of a photovoltaic system. A comparison of these systems, as against the provisions of the 1984 National Electrical Code covering photovoltaicmore » systems is made. A discussion of the UL investigation of the photovoltaic module evaluated to the provisions of the Proposed UL Standard for Flat-Plate Photovoltaic Modules and Panels is included. Grounding systems, their basis and nature, and the advantages and disadvantages of each are described. The meaning of frame grounding, circuit grounding, and the type of circuit ground are covered. The development of the Standard for Flat-Plate Photovoltaic Modules and Panels has continued, and with both industry comment and a product submittal and listing, the Standard has been refined to a viable document allowing an objective safety review of photovoltaic modules and panels. How this document, and other UL documents would cover investigations of certain other photovoltaic system components is described.« less

Development of Surfaces Optically Suitable for Flat Solar Panels. [using a reflectometer which separately evaluates spectral and diffuse reflectivities of surfaces

NASA Technical Reports Server (NTRS)

1979-01-01

A reflectometer which can separately evaluate the spectral and diffuse reflectivities of surfaces is described. A phase locked detection system for the reflectometer is also described. A selective coating on aluminum potentially useful for flat plate solar collector applications is presented. The coating is composed of strongly bound copper oxide (divalent) and is formed by an etching process performed on an aluminum alloy with high copper content. Fabrication costs are expected to be small due to the one stop fabrication process. A number of conclusions gathered from the literature as to the required optical properties of flat plate solar collectors are discussed.

Urothelial dysplasia and other flat lesions of the urinary bladder: clinicopathologic and molecular features.

PubMed

Hodges, Kurt B; Lopez-Beltran, Antonio; Davidson, Darrell D; Montironi, Rodolfo; Cheng, Liang

2010-02-01

The 2004 World Health Organization classification system for urothelial neoplasia classifies flat-related preneoplastic lesions as urothelial hyperplasia (flat and papillary), reactive urothelial atypia, urothelial atypia of unknown significance, urothelial dysplasia (low-grade intraurothelial neoplasia), and urothelial carcinoma in situ (high-grade intraurothelial neoplasia). Each lesion is defined with precise nomenclature and strict morphologic criteria. In many cases, morphologic features alone suffice for diagnosis. Other cases may require a panel of immunohistochemical antibodies consisting of cytokeratin 20, p53, and CD44 for diagnosis. Recent molecular studies have provided further insight into the premalignant potential of these urothelial lesions. Herein, we present a review of flat urothelial lesions of the urinary bladder as defined by the 2004 World Health Organization classification with focus on the clinicopathologic, immunohistochemical, and molecular features. Copyright 2010 Elsevier Inc. All rights reserved.

Symptomatic accommodative and binocular dysfunctions from the use of flat-panel displays

PubMed Central

Porcar, Esteban; Montalt, Juan Carlos; Pons, Álvaro M.; España-Gregori, Enrique

2018-01-01

AIM To determine the presence of symptomatic accommodative and non-strabismic binocular dysfunctions (ANSBD) in a non-presbyopic population of video display unit (VDU) users with flat-panel displays. METHODS One hundred and one VDU users, aged between 20 to 34y, initially participated in the study. This study excluded contact-lens wearers and subjects who had undergone refractive surgery or had any systemic or ocular disease. First, subjects were asked about the type and nature of eye symptoms they experienced during VDU use. Then, a thorough eye examination excluded those subjects with a significant uncorrected refractive error or other problem, such as ocular motility disorders, vertical deviation, strabismus and eye diseases. Finally, the remaining participants underwent an exhaustive assessment of their accommodative and binocular vision status. RESULTS Eighty-nine VDU users (46 females and 43 males) were included in this study. They used flat-panel displays for an average of 5±1.9h a day. Twenty subjects presented ANSBD (22.5%). Convergence excess was the most frequent non-strabismic binocular dysfunction (9 subjects), followed by fusional vergence dysfunction (3 subjects) and convergence insufficiency (2 subjects). Within the accommodative dysfunctions, accommodative excess was the most common (4 subjects), followed by accommodative insufficiency (2 subjects). Moderate to severe eye symptoms were found in 13 subjects with ANSBD. CONCLUSION Significant eye symptoms in VDU users with accommodative and/or non-strabismic binocular dysfunctions often occur and should not be underestimated; therefore, an appropriate evaluation of accommodative and binocular vision status is more important for this population. PMID:29600186

Metal artifact reduction for flat panel detector intravenous CT angiography in patients with intracranial metallic implants after endovascular and surgical treatment.

PubMed

Pjontek, Rastislav; Önenköprülü, Belgin; Scholz, Bernhard; Kyriakou, Yiannis; Schubert, Gerrit A; Nikoubashman, Omid; Othman, Ahmed; Wiesmann, Martin; Brockmann, Marc A

2016-08-01

Flat panel detector CT angiography with intravenous contrast agent injection (IV CTA) allows high-resolution imaging of cerebrovascular structures. Artifacts caused by metallic implants like platinum coils or clips lead to degradation of image quality and are a significant problem. To evaluate the influence of a prototype metal artifact reduction (MAR) algorithm on image quality in patients with intracranial metallic implants. Flat panel detector CT after intravenous application of 80 mL contrast agent was performed with an angiography system (Artis zee; Siemens, Forchheim, Germany) using a 20 s rotation protocol (200° rotation angle, 20 s acquisition time, 496 projections). The data before and after MAR of 26 patients with a total of 34 implants (coils, clips, stents) were independently evaluated by two blinded neuroradiologists. MAR improved the assessability of the brain parenchyma and small vessels (diameter <1 mm) in the neighborhood of metallic implants and at a distance of 6 cm (p<0.001 each, Wilcoxon test). Furthermore, MAR significantly improved the assessability of parent vessel patency and potential aneurysm remnants (p<0.005 each, McNemar test). MAR, however, did not improve assessability of stented vessels. When an intravenous contrast protocol is used, MAR significantly ameliorates the assessability of brain parenchyma, vessels, and treated aneurysms in patients with intracranial coils or clips. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Residual Strength Analyses of Monolithic Structures

NASA Technical Reports Server (NTRS)

Forth, Scott (Technical Monitor); Ambur, Damodar R. (Technical Monitor); Seshadri, B. R.; Tiwari, S. N.

2003-01-01

Finite-element fracture simulation methodology predicts the residual strength of damaged aircraft structures. The methodology uses the critical crack-tip-opening-angle (CTOA) fracture criterion to characterize the fracture behavior of the material. The CTOA fracture criterion assumes that stable crack growth occurs when the crack-tip angle reaches a constant critical value. The use of the CTOA criterion requires an elastic- plastic, finite-element analysis. The critical CTOA value is determined by simulating fracture behavior in laboratory specimens, such as a compact specimen, to obtain the angle that best fits the observed test behavior. The critical CTOA value appears to be independent of loading, crack length, and in-plane dimensions. However, it is a function of material thickness and local crack-front constraint. Modeling the local constraint requires either a three-dimensional analysis or a two-dimensional analysis with an approximation to account for the constraint effects. In recent times as the aircraft industry is leaning towards monolithic structures with the intention of reducing part count and manufacturing cost, there has been a consistent effort at NASA Langley to extend critical CTOA based numerical methodology in the analysis of integrally-stiffened panels.In this regard, a series of fracture tests were conducted on both flat and curved aluminum alloy integrally-stiffened panels. These flat panels were subjected to uniaxial tension and during the test, applied load-crack extension, out-of-plane displacements and local deformations around the crack tip region were measured. Compact and middle-crack tension specimens were tested to determine the critical angle (wc) using three-dimensional code (ZIP3D) and the plane-strain core height (hJ using two-dimensional code (STAGS). These values were then used in the STAGS analysis to predict the fracture behavior of the integrally-stiffened panels. The analyses modeled stable tearing, buckling, and crack branching at the integral stiffener using different values of critical CTOA for different material thicknesses and orientation. Comparisons were made between measured and predicted load-crack extension, out-of-plane displacements and local deformations around the crack tip region. Simultaneously, three-dimensional capabilities to model crack branching and to monitor stable crack growth of multiple cracks in a large thick integrally-stiffened flat panels were implemented in three-dimensional finite element code (ZIP3D) and tested by analyzing the integrally-stiffened panels tested at Alcoa. The residual strength of the panels predicted from STAGS and ZP3D code compared very well with experimental data. In recent times, STAGS software has been updated with new features and now one can have combinations of solid and shell elements in the residual strength analysis of integrally-stiffened panels.

Postbuckling behavior of graphite-epoxy panels

NASA Technical Reports Server (NTRS)

Starnes, J. H., Jr.; Dickson, J. N.; Rouse, M.

1984-01-01

Structurally efficient fuselage panels are often designed to allow buckling to occur at applied loads below ultimate. Interest in applying graphite-epoxy materials to fuselage primary structure led to several studies of the post-buckling behavior of graphite-epoxy structural components. Studies of the postbuckling behavior of flat and curved, unstiffened and stiffened graphite-epoxy panels loaded in compression and shear were summarized. The response and failure characteristics of specimens studied experimentally were described, and analytical and experimental results were compared. The specimens tested in the studies described were fabricated from commercially available 0.005-inch-thick unidirectional graphite-fiber tapes preimpregnated with 350 F cure thermosetting epoxy resins.

Construction and characterization of spherical Si solar cells combined with SiC electric power inverter

NASA Astrophysics Data System (ADS)

Oku, Takeo; Matsumoto, Taisuke; Hiramatsu, Kouichi; Yasuda, Masashi; Shimono, Akio; Takeda, Yoshikazu; Murozono, Mikio

2015-02-01

Spherical silicon (Si) photovoltaic solar cell systems combined with an electric power inverter using silicon carbide (SiC) field-effect transistor (FET) were constructed and characterized, which were compared with an ordinary Si-based converter. The SiC-FET devices were introduced in the direct current-alternating current (DC-AC) converter, which was connected with the solar panels. The spherical Si solar cells were used as the power sources, and the spherical Si panels are lighter and more flexible compared with the ordinary flat Si solar panels. Conversion efficiencies of the spherical Si solar cells were improved by using the SiC-FET.

Fabrication and characteristics of high-performance and high-stability aluminum-doped zinc oxide thin-film transistors

NASA Astrophysics Data System (ADS)

Shan, Dongfang; Han, Dedong; Huang, Fuqing; Tian, Yu; Zhang, Suoming; Qi, Lin; Cong, Yingying; Zhang, Shengdong; Zhang, Xing; Wang, Yi

2014-01-01

Fully transparent aluminum-doped zinc oxide (AZO) thin-film transistors (TFTs) were successfully fabricated on glass substrates at room temperature. Superior properties, such as a high saturation mobility of 59.3 cm2 V-1 s-1, a positive threshold voltage of 1.3 V, a steep subthreshold swing of 122.9 mV/dec, an off-state current on the order of 10-12 A, and an on/off ratio of 2.7 × 108, were obtained. The electrical properties of the AZO TFTs were successively studied within a period of six months. Small property degenerations could be observed from the test results obtained within the study period, which proved the high-performance and high-stability characteristics of AZO TFTs. Furthermore, hysteresis loop scanning of AZO TFTs was performed, and a small hysteresis could be detected in the scanning curves, which suggested the superior properties of a dielectric and a channel-insulator interface. Lastly, we succeeded in manufacturing an organic LED (OLED) flat panel display panel driven by AZO TFTs and obtained an excellent display effect from it. We believe that AZO TFTs are a promising candidate successor to Si-based TFTs in next-generation flat panel displays.

Compact flat-panel gas-gap heat switch operating at 295 K

NASA Astrophysics Data System (ADS)

Krielaart, M. A. R.; Vermeer, C. H.; Vanapalli, S.

2015-11-01

Heat switches are devices that can change from a thermally conducting (on-) state to an insulating (off-) state whenever the need arises. They enable adaptive thermal management strategies in which cooling rates are altered either spatially or temporally, leading to a substantial reduction in the energy and mass budget of a large range of systems. State-of-the-art heat switches are only rarely employed in thermal system architectures, since they are rather bulky and have a limited thermal performance (expressed as the heat transfer ratio between the on- and off-state heat conductance). Using selective laser melting additive manufacturing technology, also known as 3D printing, we developed a compact flat-panel gas-gap heat switch that offers superior thermal performance, is simpler and more economic to produce and assemble, contains no moving parts, and is more reliable because it lacks welded joints. The manufactured rectangular panel heat switch has frontal device dimensions of 10 cm by 10 cm, thickness of 3.2 mm and weighs just 121 g. An off heat conductance of 0.2 W/K and on-off heat conductance ratio of 38 is observed at 295 K.

Investigation of time-resolved proton radiography using x-ray flat-panel imaging system

NASA Astrophysics Data System (ADS)

Jee, K.-W.; Zhang, R.; Bentefour, E. H.; Doolan, P. J.; Cascio, E.; Sharp, G.; Flanz, J.; Lu, H.-M.

2017-03-01

Proton beam therapy benefits from the Bragg peak and delivers highly conformal dose distributions. However, the location of the end-of-range is subject to uncertainties related to the accuracy of the relative proton stopping power estimates and thereby the water-equivalent path length (WEPL) along the beam. To remedy the range uncertainty, an in vivo measurement of the WEPL through the patient, i.e. a proton-range radiograph, is highly desirable. Towards that goal, we have explored a novel method of proton radiography based on the time-resolved dose measured by a flat panel imager (FPI). A 226 MeV pencil beam and a custom-designed range modulator wheel (MW) were used to create a time-varying broad beam. The proton imaging technique used exploits this time dependency by looking at the dose rate at the imager as a function of time. This dose rate function (DRF) has a unique time-varying dose pattern at each depth of penetration. A relatively slow rotation of the MW (0.2 revolutions per second) and a fast image acquisition (30 frames per second, ~33 ms sampling) provided a sufficient temporal resolution for each DRF. Along with the high output of the CsI:Tl scintillator, imaging with pixel binning (2  ×  2) generated high signal-to-noise data at a very low radiation dose (~0.1 cGy). Proton radiographs of a head phantom and a Gammex CT calibration phantom were taken with various configurations. The results of the phantom measurements show that the FPI can generate low noise and high spatial resolution proton radiographs. The WEPL values of the CT tissue surrogate inserts show that the measured relative stopping powers are accurate to ~2%. The panel did not show any noticeable radiation damage after the accumulative dose of approximately 3831 cGy. In summary, we have successfully demonstrated a highly practical method of generating proton radiography using an x-ray flat panel imager.

Investigation of time-resolved proton radiography using x-ray flat-panel imaging system.

PubMed

Jee, K-W; Zhang, R; Bentefour, E H; Doolan, P J; Cascio, E; Sharp, G; Flanz, J; Lu, H-M

2017-03-07

Proton beam therapy benefits from the Bragg peak and delivers highly conformal dose distributions. However, the location of the end-of-range is subject to uncertainties related to the accuracy of the relative proton stopping power estimates and thereby the water-equivalent path length (WEPL) along the beam. To remedy the range uncertainty, an in vivo measurement of the WEPL through the patient, i.e. a proton-range radiograph, is highly desirable. Towards that goal, we have explored a novel method of proton radiography based on the time-resolved dose measured by a flat panel imager (FPI). A 226 MeV pencil beam and a custom-designed range modulator wheel (MW) were used to create a time-varying broad beam. The proton imaging technique used exploits this time dependency by looking at the dose rate at the imager as a function of time. This dose rate function (DRF) has a unique time-varying dose pattern at each depth of penetration. A relatively slow rotation of the MW (0.2 revolutions per second) and a fast image acquisition (30 frames per second, ~33 ms sampling) provided a sufficient temporal resolution for each DRF. Along with the high output of the CsI:Tl scintillator, imaging with pixel binning (2  ×  2) generated high signal-to-noise data at a very low radiation dose (~0.1 cGy). Proton radiographs of a head phantom and a Gammex CT calibration phantom were taken with various configurations. The results of the phantom measurements show that the FPI can generate low noise and high spatial resolution proton radiographs. The WEPL values of the CT tissue surrogate inserts show that the measured relative stopping powers are accurate to ~2%. The panel did not show any noticeable radiation damage after the accumulative dose of approximately 3831 cGy. In summary, we have successfully demonstrated a highly practical method of generating proton radiography using an x-ray flat panel imager.

Field-Sensitive Materials for Optical Applications

NASA Technical Reports Server (NTRS)

Choi, Sang H.; Little, Mark

2002-01-01

The purpose of investigation is to develop the fundamental materials and fabrication technology for field-controlled spectrally active optics that are essential for industry, NASA, and DOD (Department of Defense) applications such as: membrane optics, filters for LIDARs (Light Detection and Ranging), windows for sensors and probes, telescopes, spectroscopes, cameras, light valves, light switches, flat-panel displays, etc. The proposed idea is based on the quantum-dots (QD) array or thin-film of field-sensitive Stark and Zeeman materials and the bound excitonic state of organic crystals that will offer optical adaptability and reconfigurability. Major tasks are the development of concept demonstration article and test data of field-controlled spectrally smart active optics (FCSAO) for optical multi-functional capabilities on a selected spectral range.

The Apple IIc.

ERIC Educational Resources Information Center

Freiberger, Paul

1984-01-01

Description of the portable Apple IIc includes its flat panel display; a new microprocessor, the 65CO2; its new design language; layout; documentation, including interactive tutorials; software support; and cost. Apple IIc's competitors and its new printer, the Scribe, are also discussed. (MBR)

Guide to Air Cleaners in the Home

MedlinePlus

... In-duct Particle Removal Flat or panel air filters Pleated or extended surface filters In-duct Gaseous Pollutant Removal In-duct Pollutant ... can remove particles from the air — mechanical air filters and electronic air cleaners. Mechanical air filters remove ...

76 FR 71922 - Revisions to the California State Implementation Plan, Placer County Air Pollution Control...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-21

... from coatings and strippers used on wood products, wood paneling, and miscellaneous metal parts and...: PCAPCD Rule 236 (Wood Products and Coating Operations), PCAPCD Rule 238 (Factory Coating of Flat Wood...

Fog water collection and reforestation at mountain locations in a western Mediterranean basin region

NASA Astrophysics Data System (ADS)

Valiente, Ja; Estrela, Mj; Corell, D.; Fuentes, D.; Valdecantos, A.

2010-07-01

Previous studies carried out by the authors have shown the potential of fog water collection at several mountain locations in the Valencia region (western Mediterranean basin). This coastal region features typical conditions for a dry Mediterranean climate characterized by a pluviometric regime ranging from 400 to 600 mm with a strong annual dependence. Dry conditions together with land degradation that frequently results after recurrent fires occurred in the past make a difficult self-recovery for native forest vegetation so that some kind of human intervention is always recommended. In plots reforested with Mediterranean woody species, periods of more than 120 days without significant precipitation (>5 mm) result in mortality rates above 80% during the first summer in the field. The good potential of fog-water collection at certain mountain locations is considered in this study as an easily available water resource for the reforestation of remote areas where native vegetation cannot be reestablished by itself. A large flat panel made of UV-resistant HD-polyethylene monofilament mesh was deployed at a mountain location for bulk fog water harvesting. Water was stored in high-capacity tanks for the whole length of the experimental campaign and small timely water pulses localized deep in the planting holes were conducted during the summer dry periods. Survival rates and seedling performance of two forest tree species, Pinus pinaster and Quercus ilex, were quantified and correlated to irrigation pulses in a reforestation plot that took an area of about 2500 m2 and contained 620 1-year-old plants. Before and concurrently to the flat panel deployment, a passive omnidirectional fog-water collector of cylindrical shape was set in the area in combination to other environmental instruments such as a rain gauge, a wind direction and velocity sensor and a temperature and humidity probe. Proper orientation of the large flat panel was possible once the direction of local winds was matched up to fog occurrence and fog water yields. Additionally, a simple methodology was also found to transform fog water yields from the cylindrical collector into cumulative large flat-panel collector water catches by using wind sensor data. The method found allows an estimation of bulk fog-water catches at any single station of our fog collection network and the use of that information in future potential applications.

A hybrid finite element-transfer matrix model for vibroacoustic systems with flat and homogeneous acoustic treatments.

PubMed

Alimonti, Luca; Atalla, Noureddine; Berry, Alain; Sgard, Franck

2015-02-01

Practical vibroacoustic systems involve passive acoustic treatments consisting of highly dissipative media such as poroelastic materials. The numerical modeling of such systems at low to mid frequencies typically relies on substructuring methodologies based on finite element models. Namely, the master subsystems (i.e., structural and acoustic domains) are described by a finite set of uncoupled modes, whereas condensation procedures are typically preferred for the acoustic treatments. However, although accurate, such methodology is computationally expensive when real life applications are considered. A potential reduction of the computational burden could be obtained by approximating the effect of the acoustic treatment on the master subsystems without introducing physical degrees of freedom. To do that, the treatment has to be assumed homogeneous, flat, and of infinite lateral extent. Under these hypotheses, simple analytical tools like the transfer matrix method can be employed. In this paper, a hybrid finite element-transfer matrix methodology is proposed. The impact of the limiting assumptions inherent within the analytical framework are assessed for the case of plate-cavity systems involving flat and homogeneous acoustic treatments. The results prove that the hybrid model can capture the qualitative behavior of the vibroacoustic system while reducing the computational effort.

Development of a prototype flexible radiator system

NASA Technical Reports Server (NTRS)

Hixon, C. W.

1979-01-01

The radiator is a roll-up flexible panel with the transport fluid manifolds located at the ends of the 27 foot length. A total of fifty Teflon flow tubes are sandwiched between the layers of silver wire mesh and sealed in the Teflon film. The transport fluid flows from an inlet manifold through 25 panel flow tubes to the end of the radiator panel into a manifold which directs the fluid into the other 25 flow tubes on its return to the base of the radiator. Deployment/retraction of the flexible radiator panel is by low pressure inflation tubes (one along each side of the panel) which incorporate a flat spring. The spring supplies the retraction force to wind the radiator panel on a drum when the pressure in the inflation tubes is relieved. Room ambient deployment tests of the radiator panel were conducted to verify the inflation tube spring deployment, and retraction capability. The panel underwent a thermal vacuum, solar spectrum exposure test. After approximately 100 hours of solar exposure, post-test inspection revealed no structural or optical properties degraded.

Aerothermoelastic response analysis for C/SiC panel of ceramic matrix composite shingle thermal protection system

NASA Astrophysics Data System (ADS)

Huo, Lin; Cheng, Xing-Hua; Yang, Tao

2015-05-01

This paper presents a study of aerothermoelastic response of a C/SiC panel, which is a primary structure for ceramic matrix composite shingle thermal protection system for hypersonic vehicles. It is based on a three dimensional thermal protection shingle panel on a quasi-waverider vehicle model. Firstly, the Thin Shock Layer and piston theory are adopted to compute the aerodynamic pressure of rigid body and deformable body, and a series of engineering methods are used to compute the aerodynamic heating. Then an aerothermoelastic loosely-coupled time marching strategy and self-adapting aerodynamic heating time step are developed to analyze the aerothermoelastic response of the panel, with an aerodynamic heating and temperature field coupling parameter selection method being adopted to increase the efficiency. Finally, a few revealing conclusions are reached by analyzing how coupling at different degrees influences the quasi-static aerothermoelastic response of the panel and how aerodynamic pressure of rigid body time step influences the quasi-static aerothermoelastic response on a glide trajectory.

Progressive Failure Studies of Stiffened Panels Subjected to Shear Loading

NASA Technical Reports Server (NTRS)

Ambur, Damodar R.; Jaunky, Navin; Hilburger, Mark W.; Bushnell, Dennis M. (Technical Monitor)

2002-01-01

Experimental and analytical results are presented for progressive failure of stiffened composite panels with and without a notch and subjected to in plane shear loading well into their postbuckling regime. Initial geometric imperfections are included in the finite element models. Ply damage modes such as matrix cracking, fiber-matrix shear, and fiber failure are modeled by degrading the material properties. Experimental results from the test include strain field data from video image correlation in three dimensions in addition to other strain and displacement measurements. Results from nonlinear finite element analyses are compared with experimental data. Good agreement between experimental data and numerical results are observed for the stitched stiffened composite panels studied.

Artist: Rick Guidice Space Colonization - Bernal Sphere - The residential area is in the central

NASA Technical Reports Server (NTRS)

1976-01-01

Artist: Rick Guidice Space Colonization - Bernal Sphere - The residential area is in the central sphere. Farming regions are in the 'tires.' Mirrors reflect sunlight into the habitat and farms. The large flat panels radiate away extra heat into space, and panels of solar cells provide electricity. Factories and docks for spaceships are at either end of the long central tube. (NOTE: art printed in Book 'Space Colony - Frontier of the 21st Century by Franklyn M. Branley)

Early Detection of Amyloid Plaque in Alzheimer’s Disease via X-Ray Phase CT

DTIC Science & Technology

2014-06-01

normal, pathologic and Alzheimer’s brains, in which the amyloid precursor protein (APP) will be included as a reference. Toward this goal, we have made...in x-ray flat panel imagers and the artifact removal using a wavelet -analysis-based algorithm” Med. Phys., 28(3): 812-25, 2001. 4. X Wu and H Liu...panel imagers and the artifact removal using a wavelet -analysis-based algorithm” Med. Phys., 28(3): 812-25, 2001 12. Tang X, Hsieh J, Nilsen RA

Experimental transient and permanent deformation studies of steel-sphere-impacted or explosively-impulsed aluminum panels

NASA Technical Reports Server (NTRS)

Witmer, E. A.; Merlis, F.; Rodal, J. J. A.; Stagliano, T. R.

1977-01-01

The sheet explosive loading technique (SELT) was employed to obtain elastic-plastic, large deflection 3-d transient and/or permanent strain data on simple well defined structural specimens and materials: initially-flat 6061-T651 aluminum panels with all four sides ideally clamped via integral construction. The SELT loading technique was chosen since it is both convenient and provides "forcing function information" of small uncertainty. These data will be useful for evaluating pertinent 3-d structural response prediction methods.

A survey of new technology for cockpit application to 1990's transport aircraft simulators

NASA Technical Reports Server (NTRS)

Holt, A. P., Jr.; Noneaker, D. O.; Walthour, L.

1980-01-01

Two problems were investigated: inter-equipment data transfer, both on board the aircraft and between air and ground; and crew equipment communication via the cockpit displays and controls. Inter-equipment data transfer is discussed in terms of data bus and data link requirements. Crew equipment communication is discussed regarding the availability of CRT display systems for use in research simulators to represent flat panel displays of the future, and of software controllable touch panels.

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.

Experimental Evaluation of Tuned Chamber Core Panels for Payload Fairing Noise Control

NASA Technical Reports Server (NTRS)

Schiller, Noah H.; Allen, Albert R.; Herlan, Jonathan W.; Rosenthal, Bruce N.

2015-01-01

Analytical models have been developed to predict the sound absorption and sound transmission loss of tuned chamber core panels. The panels are constructed of two facesheets sandwiching a corrugated core. When ports are introduced through one facesheet, the long chambers within the core can be used as an array of low-frequency acoustic resonators. To evaluate the accuracy of the analytical models, absorption and sound transmission loss tests were performed on flat panels. Measurements show that the acoustic resonators embedded in the panels improve both the absorption and transmission loss of the sandwich structure at frequencies near the natural frequency of the resonators. Analytical predictions for absorption closely match measured data. However, transmission loss predictions miss important features observed in the measurements. This suggests that higher-fidelity analytical or numerical models will be needed to supplement transmission loss predictions in the future.

APPLIED ORIGAMI. Origami of thick panels.

PubMed

Chen, Yan; Peng, Rui; You, Zhong

2015-07-24

Origami patterns, including the rigid origami patterns in which flat inflexible sheets are joined by creases, are primarily created for zero-thickness sheets. In order to apply them to fold structures such as roofs, solar panels, and space mirrors, for which thickness cannot be disregarded, various methods have been suggested. However, they generally involve adding materials to or offsetting panels away from the idealized sheet without altering the kinematic model used to simulate folding. We develop a comprehensive kinematic synthesis for rigid origami of thick panels that differs from the existing kinematic model but is capable of reproducing motions identical to that of zero-thickness origami. The approach, proven to be effective for typical origami, can be readily applied to fold real engineering structures. Copyright © 2015, American Association for the Advancement of Science.

Flat or curved thin optical display panel

DOEpatents

Veligdan, James T.

1995-01-10

An optical panel 10 includes a plurality of waveguides 12 stacked together, with each waveguide 12 having a first end 12a and an opposite second end 12b. The first ends 12a collectively define a first face 16, and the second ends 12b collectively define a second face 18 of the panel 10. The second face 18 is disposed at an acute face angle relative to the waveguides 12 to provide a panel 10 which is relatively thin compared to the height of the second face. In an exemplary embodiment for use in a projection TV, the first face 16 is substantially smaller in height than the second face 18 and receives a TV image, with the second face 18 defining a screen for viewing the image enlarged.

Neah Bay Antenna Connectivity Tests and Analysis: November 19, 2001

NASA Technical Reports Server (NTRS)

Ivancic, William D.; Stewart, David; Edgein, Ken; Pansera, Vincent; Bell, Terry; Shell, Dan; Miller, Cecil

2002-01-01

The purpose of these tests was to determine the connectivity range and associated data rates for connection between the flat panel antennas on the Federal Building and the dipole and L-3 tracking antennas on the Neah Bay.

Experience in designing and using a flat structure in a multi-project research organization

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

Kurstedt, H.A. Jr.; Gardner, E.J.; Hindman, T.B. Jr.

1990-01-01

In early 1986, the organization of the Management Systems Laboratories (MSL) was changed from a standard matrix to a flat organization. The flat organization contributed more negative influences on the organization and its goals than positive ones. One year later, the flat organization was changed to a standard hierarchy and most negative influences were overcome. Before, during, and after the flat organization, MSL saw significant growth in funding and in its resource needs. This paper is an account of an experience with a type of flat organization, why we changed to that organization, what worked and what didn't, why wemore » changed away from that organization, what we learned from the experience, and what we would recommend for research organizations considering flat organizations. The authors include the founder and director of MSL, a senior manager during the experience who informally served as historian, and a manager in the organization that sponsored much of MSL's research during MSL's experience with a flat organization. 1 fig.« less

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.

Progressive Failure Studies of Composite Panels with and without Cutouts

NASA Technical Reports Server (NTRS)

Jaunky, Navin; Ambur, Damodar R.; Davila, Carlos G.; Hilburger, Mark; Bushnell, Dennis M. (Technical Monitor)

2001-01-01

Progressive failure analyses results are presented for composite panels with and without a cutout and subjected to in-plane shear loading and compression loading well into their postbuckling regime. Ply damage modes such as matrix cracking, fiber-matrix shear, and fiber failure are modeled by degrading the material properties. Results from finite element analyses are compared with experimental data. Good agreement between experimental data and numerical results are observed for most structural configurations when initial geometric imperfections are appropriately modeled.

Progressive Failure Studies of Composite Panels With and Without Cutouts

NASA Technical Reports Server (NTRS)

Ambur, Damodar R.; Jaunky, Navin; Davila, Carlos G.; Hilburger, Mark

2001-01-01

Progressive failure analyses results are presented for composite panels with and without a cutout and are subjected to in-plane shear loading and compression loading well into their post-buckling regime. Ply damage modes such as matrix cracking, fiber-matrix shear, and fiber failure are modeled by degrading the material properties. Results from finite element analyses are compared with experimental data. Good agreement between experimental data and numerical results are observed for most structural configurations when initial geometric imperfections are appropriately modeled.

Advanced and tendencies in the development of display technologies

NASA Astrophysics Data System (ADS)

Kompanets, I. N.

2006-06-01

Advances and key display applications are discussed. Computer, compact mobile, TV and collective large screen displays are mentioned. Flat panel displays step on CRT devices to leave them behind in 2007. Materials, active matricies and applications of bright radiative field emission and organic LED displays are developing successively and pressing other technologies to be used in photo-cameras, cellular phones, auto-cars and avionics. Progress in flexible screens can substantially extend the display design and application soon. 3D display systems are under intensive development, and laser is an important unit in some vaiants of holographic and volumetric 3D displays. Value forecast of different display markets is presented.

Subsonic panel method for designing wing surfaces from pressure distribution

NASA Technical Reports Server (NTRS)

Bristow, D. R.; Hawk, J. D.

1983-01-01

An iterative method has been developed for designing wing section contours corresponding to a prescribed subcritical distribution of pressure. The calculations are initialized by using a surface panel method to analyze a baseline wing or wing-fuselage configuration. A first-order expansion to the baseline panel method equations is then used to calculate a matrix containing the partial derivative of potential at each control point with respect to each unknown geometry parameter. In every iteration cycle, the matrix is used both to calculate the geometry perturbation and to analyze the perturbed geometry. The distribution of potential on the perturbed geometry is established by simple linear extrapolation from the baseline solution. The extrapolated potential is converted to pressure by Bernoulli's equation. Not only is the accuracy of the approach good for very large perturbations, but the computing cost of each complete iteration cycle is substantially less than one analysis solution by a conventional panel method.

Research on propagation properties of controllable hollow flat-topped beams in turbulent atmosphere based on ABCD matrix

NASA Astrophysics Data System (ADS)

Liu, Huilong; Lü, Yanfei; Zhang, Jing; Xia, Jing; Pu, Xiaoyun; Dong, Yuan; Li, Shutao; Fu, Xihong; Zhang, Angfeng; Wang, Changjia; Tan, Yong; Zhang, Xihe

2015-01-01

This paper studies the propagation properties of controllable hollow flat-topped beams (CHFBs) in turbulent atmosphere based on ABCD matrix, sets up a propagation model and obtains an analytical expression for the propagation. With the help of numerical simulation, the propagation properties of CHFBs in different parameters are studied. Results indicate that in turbulent atmosphere, with the increase of propagation distance, the darkness of CHFBs gradually annihilate, and eventually evolve into Gaussian beams. Compared with the propagation properties in free space, the turbulent atmosphere enhances the diffraction effect of CHFBs and reduces the propagation distance for CHFBs to evolve into Gaussian beams. In strong turbulence atmospheric propagation, Airy disk phenomenon will disappear. The study on the propagation properties of CHFBs in turbulence atmosphere by using ABCD matrix is simple and convenient. This method can also be applied to study the propagation properties of other hollow laser beams in turbulent atmosphere.

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.

Recent advances and product enhancements in reflective cholesteric displays

NASA Astrophysics Data System (ADS)

Khan, Asad; Schneider, Tod; Miller, Nick; Marhefka, Duane; Ernst, Todd; Nicholson, Forrest; Doane, Joseph W.

2005-04-01

Bistable reflective cholesteric displays are a liquid crystal display technology developed to fill a market need for very low power displays on a low-cost, high resolution passive matrix. Their unique look, high reflectivity, bistability, and simple structure make them an ideal flat panel display choice for handheld or other portable devices where small lightweight batteries with long lifetimes are important. We discuss recent advances in cholesteric display technology at Kent Displays such as progress towards single layer black and white displays, standard products, lower cost display modules, and various interface options for cholesteric display applications. It will be shown that inclusion of radio frequency (rf) control options and serial peripheral interface (spi) can greatly enhance the cholesteric display module market penetration by enabling quick integration into end devices. Finally, some discussion will be on the progress of the development of flexible reflective cholesteric displays. These flexible displays can dramatically change industrial design methods by enabling curved surfaces with displays integrated in them. Additional discussion in the paper will include applications of various display modes including signs, hand held instrumentation, and the electronic book and reader.

High temperature resin matrix composites for aerospace structures

NASA Technical Reports Server (NTRS)

Davis, J. G., Jr.

1980-01-01

Accomplishments and the outlook for graphite-polyimide composite structures are briefly outlined. Laminates, skin-stiffened and honeycomb sandwich panels, chopped fiber moldings, and structural components were fabricated with Celion/LARC-160 and Celion/PMR-15 composite materials. Interlaminar shear and flexure strength data obtained on as-fabricated specimens and specimens that were exposed for 125 hours at 589 K indicate that epoxy sized and polyimide sized Celion graphite fibers exhibit essentially the same behavior in a PMR-15 matrix composite. Analyses and tests of graphite-polyimide compression and shear panels indicate that utilization in moderately loaded applications offers the potential for achieving a 30 to 50 percent reduction in structural mass compared to conventional aluminum panels. Data on effects of moisture, temperature, thermal cycling, and shuttle fluids on mechanical properties indicate that both LARC-160 and PMR-15 are suitable matrix materials for a graphite-polyimide aft body flap. No technical road blocks to building a graphite-polyimide composite aft body flap are identified.

Simulated hail impact testing of photovoltaic solar panels

NASA Technical Reports Server (NTRS)

Moore, D.; Wilson, A.; Ross, R.

1978-01-01

Techniques used to simulate and study the effect of hail on photovoltaic solar panels are described. Simulated hail stones (frozen ice spheres projected at terminal velocity) or steel balls were applied by air guns, gravity drop, or static loading. Tests with simulated hail and steel balls yielded different results. The impact strength of 10 commercially available flat-plate photovoltaic modules was tested. It was found that none of the six panel designs incorporating clear potting silicone material as the outermost layer remained undamaged by 1-in. simulated hailstones, while a photovoltaic module equipped with a 0.188-in.-thick acrylic cover sheet would be able to withstand the impact of a 2-in.-diameter hailstone.

Exploration of maximum count rate capabilities for large-area photon counting arrays based on polycrystalline silicon thin-film transistors

NASA Astrophysics Data System (ADS)

Liang, Albert K.; Koniczek, Martin; Antonuk, Larry E.; El-Mohri, Youcef; Zhao, Qihua

2016-03-01

Pixelated photon counting detectors with energy discrimination capabilities are of increasing clinical interest for x-ray imaging. Such detectors, presently in clinical use for mammography and under development for breast tomosynthesis and spectral CT, usually employ in-pixel circuits based on crystalline silicon - a semiconductor material that is generally not well-suited for economic manufacture of large-area devices. One interesting alternative semiconductor is polycrystalline silicon (poly-Si), a thin-film technology capable of creating very large-area, monolithic devices. Similar to crystalline silicon, poly-Si allows implementation of the type of fast, complex, in-pixel circuitry required for photon counting - operating at processing speeds that are not possible with amorphous silicon (the material currently used for large-area, active matrix, flat-panel imagers). The pixel circuits of two-dimensional photon counting arrays are generally comprised of four stages: amplifier, comparator, clock generator and counter. The analog front-end (in particular, the amplifier) strongly influences performance and is therefore of interest to study. In this paper, the relationship between incident and output count rate of the analog front-end is explored under diagnostic imaging conditions for a promising poly-Si based design. The input to the amplifier is modeled in the time domain assuming a realistic input x-ray spectrum. Simulations of circuits based on poly-Si thin-film transistors are used to determine the resulting output count rate as a function of input count rate, energy discrimination threshold and operating conditions.

Low dose digital X-ray imaging with avalanche amorphous selenium

NASA Astrophysics Data System (ADS)

Scheuermann, James R.; Goldan, Amir H.; Tousignant, Olivier; Léveillé, Sébastien; Zhao, Wei

2015-03-01

Active Matrix Flat Panel Imagers (AMFPI) based on an array of thin film transistors (TFT) have become the dominant technology for digital x-ray imaging. In low dose applications, the performance of both direct and indirect conversion detectors are limited by the electronic noise associated with the TFT array. New concepts of direct and indirect detectors have been proposed using avalanche amorphous selenium (a-Se), referred to as high gain avalanche rushing photoconductor (HARP). The indirect detector utilizes a planar layer of HARP to detect light from an x-ray scintillator and amplify the photogenerated charge. The direct detector utilizes separate interaction (non-avalanche) and amplification (avalanche) regions within the a-Se to achieve depth-independent signal gain. Both detectors require the development of large area, solid state HARP. We have previously reported the first avalanche gain in a-Se with deposition techniques scalable to large area detectors. The goal of the present work is to demonstrate the feasibility of large area HARP fabrication in an a-Se deposition facility established for commercial large area AMFPI. We also examine the effect of alternative pixel electrode materials on avalanche gain. The results show that avalanche gain > 50 is achievable in the HARP layers developed in large area coaters, which is sufficient to achieve x-ray quantum noise limited performance down to a single x-ray photon per pixel. Both chromium (Cr) and indium tin oxide (ITO) have been successfully tested as pixel electrodes.

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.

Combination of CT scanning and fluoroscopy imaging on a flat-panel CT scanner

NASA Astrophysics Data System (ADS)

Grasruck, M.; Gupta, R.; Reichardt, B.; Suess, Ch.; Schmidt, B.; Stierstorfer, K.; Popescu, S.; Brady, T.; Flohr, T.

2006-03-01

We developed and evaluated a prototype flat-panel detector based Volume CT (fpVCT) scanner. The fpVCT scanner consists of a Varian 4030CB a-Si flat-panel detector mounted in a multi slice CT-gantry (Siemens Medical Solutions). It provides a 25 cm field of view with 18 cm z-coverage at the isocenter. In addition to the standard tomographic scanning, fpVCT allows two new scan modes: (1) fluoroscopic imaging from any arbitrary rotation angle, and (2) continuous, time-resolved tomographic scanning of a dynamically changing viewing volume. Fluoroscopic imaging is feasible by modifying the standard CT gantry so that the imaging chain can be oriented along any user-selected rotation angle. Scanning with a stationary gantry, after it has been oriented, is equivalent to a conventional fluoroscopic examination. This scan mode enables combined use of high-resolution tomography and real-time fluoroscopy with a clinically usable field of view in the z direction. The second scan mode allows continuous observation of a timeevolving process such as perfusion. The gantry can be continuously rotated for up to 80 sec, with the rotation time ranging from 3 to 20 sec, to gather projection images of a dynamic process. The projection data, that provides a temporal log of the viewing volume, is then converted into multiple image stacks that capture the temporal evolution of a dynamic process. Studies using phantoms, ex vivo specimens, and live animals have confirmed that these new scanning modes are clinically usable and offer a unique view of the anatomy and physiology that heretofore has not been feasible using static CT scanning. At the current level of image quality and temporal resolution, several clinical applications such a dynamic angiography, tumor enhancement pattern and vascularity studies, organ perfusion, and interventional applications are in reach.

Radiation exposure to operating staff during rotational flat-panel angiography and C-arm cone beam computed tomography (CT) applications.

PubMed

Schulz, Boris; Heidenreich, Ralf; Heidenreich, Monika; Eichler, Katrin; Thalhammer, Axel; Naeem, Naguib Nagy Naguib; Vogl, Thomas Josef; Zangos, Stefan

2012-12-01

To evaluate the radiation exposure for operating personnel associated with rotational flat-panel angiography and C-arm cone beam CT. Using a dedicated angiography-suite, 2D and 3D examinations of the liver were performed on a phantom to generate scattered radiation. Exposure was measured with a dosimeter at predefined heights (eye, thyroid, breast, gonads and knee) at the physician's location. Analysis included 3D procedures with a field of view (FOV) of 24 cm × 18 cm (8s/rotation, 20s/rotation and 5s/2 rotations), and 47 cm×18 cm (16s/2 rotations) and standard 2D angiography (10s, FOV 24 cm×18 cm). Measurements showed the highest radiation dose at the eye and thyroid level. In comparison to 2D-DSA (3.9 μSv eye-exposure), the 3D procedures caused an increased radiation exposure both in standard FOV (8s/rotation: 28.0 μSv, 20s/rotation: 79.3 μSv, 5s/2 rotations: 32.5 μSv) and large FOV (37.6 μSv). Proportional distributions were measured for the residual heights. With the use of lead glass, irradiation of the eye lens was reduced to 0.2 μSv (2D DSA) and 10.6 μSv (3D technique with 20s/rotation). Rotational flat-panel angiography and C-arm cone beam applications significantly increase radiation exposure to the attending operator in comparison to 2D angiography. Our study indicates that the physician should wear protective devices and leave the examination room when performing 3D examinations. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

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

Zhang, R; Jee, K; Sharp, G

Purpose: Proton radiography, which images the patients with the same type of particles that they are to be treated with, is a promising approach for image guidance and range uncertainties reduction. This study aimed to realize quality proton radiography by measuring dose rate functions (DRF) in time domain using a single flat panel and retrieve water equivalent path length (WEPL) from them. Methods: An amorphous silicon flat panel (PaxScan™ 4030CB, Varian Medical Systems, Inc., Palo Alto, CA) was placed behind phantoms to measure DRFs from a proton beam modulated by the modulator wheel. To retrieve WEPL and RSP, calibration modelsmore » based on the intensity of DRFs only, root mean square (RMS) of DRFs only and the intensity weighted RMS were tested. The quality of obtained WEPL images (in terms of spatial resolution and level of details) and the accuracy of WEPL were compared. Results: RSPs for most of the Gammex phantom inserts were retrieved within ± 1% errors by calibration models based on the RMS and intensity weighted RMS. The mean percentage error for all inserts was reduced from 1.08% to 0.75% by matching intensity in the calibration model. In specific cases such as the insert with a titanium rod, the calibration model based on RMS only fails while the that based on intensity weighted RMS is still valid. The quality of retrieved WEPL images were significantly improved for calibration models including intensity matching. Conclusion: For the first time, a flat panel, which is readily available in the beamline for image guidance, was tested to acquire quality proton radiography with WEPL accurately retrieved from it. This technique is promising to be applied for image-guided proton therapy as well as patient specific RSP determination to reduce uncertainties of beam ranges.« less

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.

Performance of an anisotropic Allman/DKT 3-node thin triangular flat shell element

NASA Astrophysics Data System (ADS)

Ertas, A.; Krafcik, J. T.; Ekwaro-Osire, S.

1992-05-01

A simple, explicit formulation of the stiffness matrix for an anisotropic, 3-node, thin triangular flat shell element in global coordinates is presented. An Allman triangle (AT) is used for membrane stiffness. The membrane stiffness matrix is explicitly derived by applying an Allman transformation to a Felippa 6-node linear strain triangle (LST). Bending stiffness is incorporated by the use of a discrete Kirchhoff triangle (DKT) bending element. Stiffness terms resulting from anisotropic membrane-bending coupling are included by integrating, in area coordinates, the membrane and bending strain-displacement matrices. Using the aforementioned approach, the objective of this study is to develop and test the performance of a practical 3-node flat shell element that could be used in plate problems with unsymmetrically stacked composite laminates. The performance of the latter element is tested on plates of varying aspect ratios. The developed 3-node shell element should simplify the programming task and have the potential of reducing the computational time.

48 CFR 1523.7001 - Policy.

Code of Federal Regulations, 2010 CFR

2010-10-01

... ENVIRONMENTAL, CONSERVATION, OCCUPATIONAL SAFETY, AND DRUG-FREE WORKPLACE Energy-Efficient Computer Equipment 1523.7001 Policy. (a) The “Energy Star” Executive Order (E.O. 12845) applies to the following equipment... (CRT or Flat-panel LCD). (b) “Energy Star” requirements do not apply to the following equipment: (1...

48 CFR 1523.7001 - Policy.

Code of Federal Regulations, 2011 CFR

2011-10-01

... ENVIRONMENTAL, CONSERVATION, OCCUPATIONAL SAFETY, AND DRUG-FREE WORKPLACE Energy-Efficient Computer Equipment 1523.7001 Policy. (a) The “Energy Star” Executive Order (E.O. 12845) applies to the following equipment... (CRT or Flat-panel LCD). (b) “Energy Star” requirements do not apply to the following equipment: (1...

48 CFR 1523.7001 - Policy.

Code of Federal Regulations, 2012 CFR

2012-10-01

... ENVIRONMENTAL, CONSERVATION, OCCUPATIONAL SAFETY, AND DRUG-FREE WORKPLACE Energy-Efficient Computer Equipment 1523.7001 Policy. (a) The “Energy Star” Executive Order (E.O. 12845) applies to the following equipment... (CRT or Flat-panel LCD). (b) “Energy Star” requirements do not apply to the following equipment: (1...

Monitors.

ERIC Educational Resources Information Center

Powell, David

1984-01-01

Provides guidelines for selecting a monitor to suit specific applications, explains the process by which graphics images are produced on a CRT monitor, and describes four types of flat-panel displays being used in the newest lap-sized portable computers. A comparison chart provides prices and specifications for over 80 monitors. (MBR)

76 FR 45296 - In the Matter of Certain Flat Panel Display Devices, and Products Containing the Same; Notice of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-28

...-Hsin Road 2, Hsinchu Science Park, Hsinchu 30078, Taiwan. AU Optronics Corporation America, 1525... facts to be as alleged in the complaint and this notice and to enter an initial determination and a...

Are New Image Quality Figures of Merit Needed for Flat Panel Displays?

DTIC Science & Technology

1998-06-01

American National Standard for Human Factors Engineering of Visual Display Terminal Workstations in 1988 have adopted the MTFA as the standard...References American National Standard for Human Factors Engineering of Visual Display Terminal Workstations (ANSI/HFS 100-1988). 1988. Santa Monica

Review of flat panel display programs and defense applications

NASA Astrophysics Data System (ADS)

Gnade, Bruce; Schulze, Raymond; Henderson, Girardeau L.; Hopper, Darrel G.

1997-07-01

Flat panel display research has comprised a substantial portion of the national investment in new technology for economic and national security for the past nine years. These investments have ben made principally via several Defense Advanced Research Projects Agency (DARPA) programs, known collectively as the continuing High Definition Systems Program, and the Office of the Secretary of Defense Production Act Title III Program. Using input from the Army, Navy, and Air Force to focus research and identify insertion opportunities, DARPA and the Title III Program Office have made investments to develop the national technology base and manufacturing infrastructure necessary to meet the twin challenge of providing affordable displays in current systems and enabling the DoD strategy of winning future conflicts by getting more information to all participants during the battle. These research programs are reviewed and opportunities for applications are described. Future technology development, transfer, and transition requirements are identified. Strategy and vision are documented to assist the identification of areas meriting further consideration.

Application of flat panel OLED display technology for the point-of-care detection of circulating cancer biomarkers

PubMed Central

Katchman, Benjamin A.; Smith, Joseph T.; Obahiagbon, Uwadiae; Kesiraju, Sailaja; Lee, Yong-Kyun; O’Brien, Barry; Kaftanoglu, Korhan; Blain Christen, Jennifer; Anderson, Karen S.

2016-01-01

Point-of-care molecular diagnostics can provide efficient and cost-effective medical care, and they have the potential to fundamentally change our approach to global health. However, most existing approaches are not scalable to include multiple biomarkers. As a solution, we have combined commercial flat panel OLED display technology with protein microarray technology to enable high-density fluorescent, programmable, multiplexed biorecognition in a compact and disposable configuration with clinical-level sensitivity. Our approach leverages advances in commercial display technology to reduce pre-functionalized biosensor substrate costs to pennies per cm2. Here, we demonstrate quantitative detection of IgG antibodies to multiple viral antigens in patient serum samples with detection limits for human IgG in the 10 pg/mL range. We also demonstrate multiplexed detection of antibodies to the HPV16 proteins E2, E6, and E7, which are circulating biomarkers for cervical as well as head and neck cancers. PMID:27374875

Strain Behavior of Concrete Panels Subjected to Different Nose Shapes of Projectile Impact

PubMed Central

Lee, Sangkyu; Kim, Gyuyong; Kim, Hongseop; Son, Minjae; Choe, Gyeongcheol; Nam, Jeongsoo

2018-01-01

This study evaluates the fracture properties and rear-face strain distribution of nonreinforced and hooked steel fiber-reinforced concrete panels penetrated by projectiles of three different nose shapes: sharp, hemispherical, and flat. The sharp projectile nose resulted in a deeper penetration because of the concentration of the impact force. Conversely, the flat projectile nose resulted in shallower penetrations. The penetration based on different projectile nose shapes is directly related to the impact force transmitted to the rear face. Scabbing can be more accurately predicted by the tensile strain on the rear face of concrete due to the projectile nose shape. The tensile strain on the rear face of the concrete was reduced by the hooked steel fiber reinforcement because the hooked steel fiber absorbed some of the impact stress transmitted to the rear face of the concrete. Consequently, the strain behavior on the rear face of concrete according to the projectile nose shape was confirmed. PMID:29522479

Application of flat panel OLED display technology for the point-of-care detection of circulating cancer biomarkers.

PubMed

Katchman, Benjamin A; Smith, Joseph T; Obahiagbon, Uwadiae; Kesiraju, Sailaja; Lee, Yong-Kyun; O'Brien, Barry; Kaftanoglu, Korhan; Blain Christen, Jennifer; Anderson, Karen S

2016-07-04

Point-of-care molecular diagnostics can provide efficient and cost-effective medical care, and they have the potential to fundamentally change our approach to global health. However, most existing approaches are not scalable to include multiple biomarkers. As a solution, we have combined commercial flat panel OLED display technology with protein microarray technology to enable high-density fluorescent, programmable, multiplexed biorecognition in a compact and disposable configuration with clinical-level sensitivity. Our approach leverages advances in commercial display technology to reduce pre-functionalized biosensor substrate costs to pennies per cm(2). Here, we demonstrate quantitative detection of IgG antibodies to multiple viral antigens in patient serum samples with detection limits for human IgG in the 10 pg/mL range. We also demonstrate multiplexed detection of antibodies to the HPV16 proteins E2, E6, and E7, which are circulating biomarkers for cervical as well as head and neck cancers.

Strain Behavior of Concrete Panels Subjected to Different Nose Shapes of Projectile Impact.

PubMed

Lee, Sangkyu; Kim, Gyuyong; Kim, Hongseop; Son, Minjae; Choe, Gyeongcheol; Nam, Jeongsoo

2018-03-09

This study evaluates the fracture properties and rear-face strain distribution of nonreinforced and hooked steel fiber-reinforced concrete panels penetrated by projectiles of three different nose shapes: sharp, hemispherical, and flat. The sharp projectile nose resulted in a deeper penetration because of the concentration of the impact force. Conversely, the flat projectile nose resulted in shallower penetrations. The penetration based on different projectile nose shapes is directly related to the impact force transmitted to the rear face. Scabbing can be more accurately predicted by the tensile strain on the rear face of concrete due to the projectile nose shape. The tensile strain on the rear face of the concrete was reduced by the hooked steel fiber reinforcement because the hooked steel fiber absorbed some of the impact stress transmitted to the rear face of the concrete. Consequently, the strain behavior on the rear face of concrete according to the projectile nose shape was confirmed.

[Comparison of noise characteristics of direct and indirect conversion flat panel detectors].

PubMed

Murai, Masami; Kishimoto, Kenji; Tanaka, Katsuhisa; Oota, Kenji; Ienaga, Akinori

2010-11-20

Flat-panel detector (FPD) digital radiography systems have direct and indirect conversion systems, and the 2 conversion systems provide different imaging performances. We measured some imaging performances [input-output characteristic, presampled modulation transfer function (presampled MTF), noise power spectrum (NPS)] of direct and indirect FPD systems. Moreover, some image samples of the NPSs were visually evaluated by the pair comparison method. As a result, the presampled MTF of the direct FPD system was substantially higher than that of the indirect FPD system. The NPS of the direct FPD system had a high value for all spatial frequencies. In contrast, the NPS of the indirect FPD system had a lower value as the frequency became higher. The results of visual evaluations showed the same tendency as that found for NPSs. We elucidated the cause of the difference in NPSs in a simulation study, and we determined that the cause of the difference in the noise components of the direct and indirect FPD systems was closely related to the presampled MTF.

Image degradation by glare in radiologic display devices

NASA Astrophysics Data System (ADS)

Badano, Aldo; Flynn, Michael J.

1997-05-01

No electronic devices are currently available that can display digital radiographs without loss of visual information compared to traditional transilluminated film. Light scattering within the glass faceplate of cathode-ray tube (CRT) devices causes excessive glare that reduces image contrast. This glare, along with ambient light reflection, has been recognized as a significant limitation for radiologic applications. Efforts to control the effect of glare and ambient light reflection in CRTs include the use of absorptive glass and thin film coatings. In the near future, flat panel displays (FPD) with thin emissive structures should provide very low glare, high performance devices. We have used an optical Monte Carlo simulation to evaluate the effect of glare on image quality for typical CRT and flat panel display devices. The trade-off between display brightness and image contrast is described. For CRT systems, achieving good glare ratio requires a reduction of brightness to 30-40 percent of the maximum potential brightness. For FPD systems, similar glare performance can be achieved while maintaining 80 percent of the maximum potential brightness.

Advantages and difficulties of implementation of flat-panel multimedia monitoring system in a surgical MRI suite

NASA Astrophysics Data System (ADS)

Deckard, Michael; Ratib, Osman M.; Rubino, Gregory

2002-05-01

Our project was to design and implement a ceiling-mounted multi monitor display unit for use in a high-field MRI surgical suite. The system is designed to simultaneously display images/data from four different digital and/or analog sources with: minimal interference from the adjacent high magnetic field, minimal signal-to-noise/artifact contribution to the MRI images and compliance with codes and regulations for the sterile neuro-surgical environment. Provisions were also made to accommodate the importing and exporting of video information via PACS and remote processing/display for clinical and education uses. Commercial fiber optic receivers/transmitters were implemented along with supporting video processing and distribution equipment to solve the video communication problem. A new generation of high-resolution color flat panel displays was selected for the project. A custom-made monitor mount and in-suite electronics enclosure was designed and constructed at UCLA. Difficulties with implementing an isolated AC power system are discussed and a work-around solution presented.

Lung imaging of laboratory rodents in vivo

NASA Astrophysics Data System (ADS)

Cody, Dianna D.; Cavanaugh, Dawn; Price, Roger E.; Rivera, Belinda; Gladish, Gregory; Travis, Elizabeth

2004-10-01

We have been acquiring respiratory-gated micro-CT images of live mice and rats for over a year with our General Electric (formerly Enhanced Vision Systems) hybrid scanner. This technique is especially well suited for the lung due to the inherent high tissue contrast. Our current studies focus on the assessment of lung tumors and their response to experimental agents, and the assessment of lung damage due to chemotherapy agents. We have recently installed a custom-built dual flat-panel cone-beam CT scanner with the ability to scan laboratory animals that vary in size from mice to large dogs. A breath-hold technique is used in place of respiratory gating on this scanner. The objective of this pilot study was to converge on scan acquisition parameters and optimize the visualization of lung damage in a mouse model of fibrosis. Example images from both the micro-CT scanner and the flat-panel CT scanner will be presented, as well as preliminary data describing spatial resolution, low contrast resolution, and radiation dose parameters.

High-energy X-ray diffraction using the Pixium 4700 flat-panel detector.

PubMed

Daniels, J E; Drakopoulos, M

2009-07-01

The Pixium 4700 detector represents a significant step forward in detector technology for high-energy X-ray diffraction. The detector design is based on digital flat-panel technology, combining an amorphous Si panel with a CsI scintillator. The detector has a useful pixel array of 1910 x 2480 pixels with a pixel size of 154 microm x 154 microm, and thus it covers an effective area of 294 mm x 379 mm. Designed for medical imaging, the detector has good efficiency at high X-ray energies. Furthermore, it is capable of acquiring sequences of images at 7.5 frames per second in full image mode, and up to 60 frames per second in binned region of interest modes. Here, the basic properties of this detector applied to high-energy X-ray diffraction are presented. Quantitative comparisons with a widespread high-energy detector, the MAR345 image plate scanner, are shown. Other properties of the Pixium 4700 detector, including a narrow point-spread function and distortion-free image, allows for the acquisition of high-quality diffraction data at high X-ray energies. In addition, high frame rates and shutterless operation open new experimental possibilities. Also provided are the necessary data for the correction of images collected using the Pixium 4700 for diffraction purposes.

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.

1. VIEW OF A PORTION OF THE HYDRIDE PROCESSING LABORATORY. ...

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

1. VIEW OF A PORTION OF THE HYDRIDE PROCESSING LABORATORY. OPERATIONS IN THE GLOVE BOX IN THE BACKGROUND OF THE PHOTOGRAPH INCLUDED HYDRIDING OF PLUTONIUM AND HYDRIDE SEPARATION. IN THE FOREGROUND, THE VACUUM MONITOR CONTROL PANEL MEASURED TEMPERATURES WITHIN THE GLOVEBOX. THE CENTER CONTROL PANEL REGULATED THE FURNACE INSIDE THE GLOVE BOX USED IN THE HYDRIDING PROCESSES. THIS EQUIPMENT WAS ESSENTIAL TO THE HYDRIDING PROCESS, AS WELL AS OTHER GLOVE BOX OPERATIONS. - Rocky Flats Plant, Plutonium Laboratory, North-central section of industrial area at 79 Drive, Golden, Jefferson County, CO

Ceramic Matrix Composite Characterization Under a Combustion and Loading Environment

DTIC Science & Technology

2009-03-01

work showed that the material is sensitive in fatigue to center holes above 84% UTS. Barth Boyer did fatigue and creep testing double edge notched...panel obtained for this test was also used in previous AFIT thesis work by Boyer . It is a 12 in x 12 in panel consisting of an eight harness satin...weave with a [0°/90°] fiber orientation. The panel number is 4569-2. The panel properties obtained by Boyer are in Table 3. 17 Table 3

Moving zone Marangoni drying of wet objects using naturally evaporated solvent vapor

DOEpatents

Britten, Jerald A.

1997-01-01

A surface tension gradient driven flow (a Marangoni flow) is used to remove the thin film of water remaining on the surface of an object following rinsing. The process passively introduces by natural evaporation and diffusion of minute amounts of alcohol (or other suitable material) vapor in the immediate vicinity of a continuously refreshed meniscus of deionized water or another aqueous-based, nonsurfactant rinsing agent. Used in conjunction with cleaning, developing or wet etching application, rinsing coupled with Marangoni drying provides a single-step process for 1) cleaning, developing or etching, 2) rinsing, and 3) drying objects such as flat substrates or coatings on flat substrates without necessarily using heat, forced air flow, contact wiping, centrifugation or large amounts of flammable solvents. This process is useful in one-step cleaning and drying of large flat optical substrates, one-step developing/rinsing and drying or etching/rinsing/drying of large flat patterned substrates and flat panel displays during lithographic processing, and room-temperature rinsing/drying of other large parts, sheets or continuous rolls of material.

Moving zone Marangoni drying of wet objects using naturally evaporated solvent vapor

DOEpatents

Britten, J.A.

1997-08-26

A surface tension gradient driven flow (a Marangoni flow) is used to remove the thin film of water remaining on the surface of an object following rinsing. The process passively introduces by natural evaporation and diffusion of minute amounts of alcohol (or other suitable material) vapor in the immediate vicinity of a continuously refreshed meniscus of deionized water or another aqueous-based, nonsurfactant rinsing agent. Used in conjunction with cleaning, developing or wet etching application, rinsing coupled with Marangoni drying provides a single-step process for (1) cleaning, developing or etching, (2) rinsing, and (3) drying objects such as flat substrates or coatings on flat substrates without necessarily using heat, forced air flow, contact wiping, centrifugation or large amounts of flammable solvents. This process is useful in one-step cleaning and drying of large flat optical substrates, one-step developing/rinsing and drying or etching/rinsing/drying of large flat patterned substrates and flat panel displays during lithographic processing, and room-temperature rinsing/drying of other large parts, sheets or continuous rolls of material. 5 figs.

76 FR 63657 - Certain Flat Panel Display Devices, and Products Containing the Same; Notice of Commission...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-13

... the same by reason of infringement of various claims of United States Patent Nos. 6,281,955; 7,697,093... Mobility LLC of Atlanta, Georgia; Best Buy Stores, L.P. of Richfield, Minnesota; BestBuy.com , LLC of Eden...

75 FR 70692 - TUV Rheinland PTL, LLC; Application for Recognition

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-18

... was current at the time OSHA prepared this notice. UL 1703 Flat-Plate Photovoltaic Modules and Panels... for photovoltaic products, and a leading test organization for photovoltaic technology. Arizona State University (ASU) established the organization in 1992, as the Photovoltaic Testing Laboratory (PTL). The...

77 FR 75617 - 36(b)(1) Arms Sales Notification

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-21

... transmittal, policy justification, and Sensitivity of Technology. Dated: December 18, 2012. Aaron Siegel... Processor Cabinets, 2 Video Wall Screen and Projector Systems, 46 Flat Panel Displays, and 2 Distributed Video Systems), 2 ship sets AN/SPQ-15 Digital Video Distribution Systems, 2 ship sets Operational...

Designing low cost LED display for the billboard

NASA Astrophysics Data System (ADS)

Hong, Yi-Jian; Uang, Chii-Maw; Wang, Ping-Chieh; Ho, Zu-Sheng

2011-10-01

With quickly advance of the computer, microelectronics and photonics technologies, LED display panel becomes a new electronic advertising media. It can be used to show any information whatever characters or graphics. Most LED display panels are built of many Light-Emitting Diodes arranged in a matrix form. The display has many advantages such as low power, low cost, long life and high definition. Because the display panel is asked to show rich color, the LED display panel's driving system becomes very complex. The design methodology of LED display panel's driver becomes more and more important to meet the market requirements. Cost is always the most important issue in public market domain. In this paper, we report a design methodology of LED display panel's driver based on the microprocessor control unit (MCU) system and LED display controller IC, HT1632C, to control three colors, RGB, color LED display panel and the modular panel size is 24*16 in matrix form. The HT1632C is a memory mapping LED display controller, it can be used on many applications, such as digital clock, thermometer, counter, voltmeter or other instrumentation readouts. Three pieces of HT1632C are used to drive a 24*16 RGB LED display panel, in our design case. Each HT163C chip is used to control one of the R, G and B color. As the drive mode is driven in DC mode, the RGB display panel can create and totally of seven colors under the control of MCU. The MCU generates the control signal to drive HT1632C. In this study, the software design methodology is adopted with dynamic display principle. When the scan frequency is 60Hz, LED display panel will get the clear picture and be able to display seven colors.

Design and analysis of grid stiffened fuselage panel with curved stiffeners

NASA Astrophysics Data System (ADS)

Hemanth, Bharath; Babu, N. C. Mahendra; Shivakumar, H. G.; Srikari, S.

2018-04-01

Designing and analyzing grid stiffened panel to understand the effect of stiffeners on stiffness of the panel is crucial in designing grid stiffened cylinder for fuselage application. Traditionally only straight stiffeners were used due to limited manufacturing capabilities and in recent years GSS with curved stiffeners have become a reality. The present work is on flat grid stiffened panel and the focus is to realize the change in stiffness by converting straight stiffeners in an isogrid panel to curved stiffeners. An isogrid stiffened panel is identified from literature for which experimental results were available and was considered for replacing straight stiffeners with curved stiffeners. Defining and designing the curve for curved stiffeners which can be used to replace straight stiffeners in isogrid pattern is crucial. FE model of the grid stiffened fuselage panel with isogrid pattern identified from the literature for which experimental data was available was developed and evaluated for stiffness. For the same panel, curved grid pattern to enhance stiffness of the panel was designed following existing design procedure. FE model of the grid stiffened fuselage panel with designed curved stiffeners was developed and evaluated for stiffness. It is established that the stiffness of panel can be increased by minimum of 2.82% to maximum of 11.93% by using curved stiffeners of particular curvature as a replacement for straight stiffeners in isogrid pattern with a slight mass penalty.

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).

A research program to reduce interior noise in general aviation airplanes. Influence of depressurization and damping material on the noise reduction characteristics of flat and curved stiffened panels

NASA Technical Reports Server (NTRS)

Navaneethan, R.; Streeter, B.; Koontz, S.; Roskam, J.

1981-01-01

Some 20 x 20 aluminum panels were studied in a frequency range from 20 Hz to 5000 Hz. The noise sources used were a swept sine wave generator and a random noise generator. The effect of noise source was found to be negligible. Increasing the pressure differential across the panel gave better noise reduction below the fundamental resonance frequency due to an increase in stiffness. The largest increase occurred in the first 1 psi pressure differential. The curved, stiffened panel exhibited similar behavior, but with a lower increase of low frequency noise reduction. Depressurization on these panels resulted in decreased noise reduction at higher frequencies. The effect of damping tapes on the overall noise reduction values of the test specimens was small away from the resonance frequency. In the mass-law region, a slight and proportional improvement in noise reduction was observed by adding damping material. Adding sound absorbtion material to a panel with damping material beneficially increased noise reduction at high frequencies.

Patterns of Expression in the Matrix Proteins Responsible for Nucleation and Growth of Aragonite Crystals in Flat Pearls of Pinctada fucata

PubMed Central

Xiang, Liang; Su, Jingtan; Zheng, Guilan; Liang, Jian; Zhang, Guiyou; Wang, Hongzhong; Xie, Liping; Zhang, Rongqing

2013-01-01

The initial growth of the nacreous layer is crucial for comprehending the formation of nacreous aragonite. A flat pearl method in the presence of the inner-shell film was conducted to evaluate the role of matrix proteins in the initial stages of nacre biomineralization in vivo. We examined the crystals deposited on a substrate and the expression patterns of the matrix proteins in the mantle facing the substrate. In this study, the aragonite crystals nucleated on the surface at 5 days in the inner-shell film system. In the film-free system, the calcite crystals nucleated at 5 days, a new organic film covered the calcite, and the aragonite nucleated at 10 days. This meant that the nacre lamellae appeared in the inner-shell film system 5 days earlier than that in the film-free system, timing that was consistent with the maximum level of matrix proteins during the first 20 days. In addition, matrix proteins (Nacrein, MSI60, N19, N16 and Pif80) had similar expression patterns in controlling the sequential morphologies of the nacre growth in the inner-film system, while these proteins in the film-free system also had similar patterns of expression. These results suggest that matrix proteins regulate aragonite nucleation and growth with the inner-shell film in vivo. PMID:23776687

A Natural Language for AdS/CFT Correlators

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

Fitzpatrick, A.Liam; /Boston U.; Kaplan, Jared

2012-02-14

We provide dramatic evidence that 'Mellin space' is the natural home for correlation functions in CFTs with weakly coupled bulk duals. In Mellin space, CFT correlators have poles corresponding to an OPE decomposition into 'left' and 'right' sub-correlators, in direct analogy with the factorization channels of scattering amplitudes. In the regime where these correlators can be computed by tree level Witten diagrams in AdS, we derive an explicit formula for the residues of Mellin amplitudes at the corresponding factorization poles, and we use the conformal Casimir to show that these amplitudes obey algebraic finite difference equations. By analyzing the recursivemore » structure of our factorization formula we obtain simple diagrammatic rules for the construction of Mellin amplitudes corresponding to tree-level Witten diagrams in any bulk scalar theory. We prove the diagrammatic rules using our finite difference equations. Finally, we show that our factorization formula and our diagrammatic rules morph into the flat space S-Matrix of the bulk theory, reproducing the usual Feynman rules, when we take the flat space limit of AdS/CFT. Throughout we emphasize a deep analogy with the properties of flat space scattering amplitudes in momentum space, which suggests that the Mellin amplitude may provide a holographic definition of the flat space S-Matrix.« less

Nanoparticle Phosphors Manufactured Using the Bicontinuous Cubic Phase Process

DTIC Science & Technology

1997-11-18

due to the recent interest in developing emissive 13 flat panel displays, e.g. full-color low-voltage field eminer displays (FEDs), large area plasma...it was determined that the nanoparticles were 5 monocrystalline with a zinc-blende cubic lattice. 6 7 Example 2 - Photoluminescence studies 8

Push/Push Fastener

NASA Technical Reports Server (NTRS)

Jackson, Steven A.

1996-01-01

Modified version of Nylatch (or equivalent) commerical quick-connect/quick-disconnect fastener for joining flat panels. Fastener tightened by pushing on knob on one side and loosened by pushing on knob on other side. Push/push operation of fastener advantageous in cold or otherwise hostile environments where gloves worn, in underwater operations, or if person handicapped.

77 FR 23130 - Revisions to the California State Implementation Plan, Northern Sierra and Sacramento...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-18

... taking direct final action to approve revisions to the Northern Sierra Air Quality Management District (NSAQMD) and Sacramento Metropolitan Air Quality Management District (SMAQMD) portions of the California...) Northern Sierra Air Quality Management District. (i) Flexible Package Printing, Flat Wood Paneling Coatings...

Development, testing, and certification of life sciences engineering solar collector

NASA Technical Reports Server (NTRS)

Caudle, J. M.

1978-01-01

Results are presented for the development of an air flat plate collector for use with solar heating, combined heating and cooling, and hot water systems. The contract was for final development, testing, and certification of the collector, and for delivery of a 320 square feet collector panel.

Cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS flat panel detector: Visibility of simulated microcalcifications

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

Shen, Youtao; Zhong, Yuncheng; Lai, Chao-Jen

2013-10-15

Purpose: To measure and investigate the improvement of microcalcification (MC) visibility in cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS/CsI flat panel detector (Dexela 2923, Perkin Elmer).Methods: Aluminum wires and calcium carbonate grains of various sizes were embedded in a paraffin cylinder to simulate imaging of calcifications in a breast. Phantoms were imaged with a benchtop experimental cone beam CT system at various exposure levels. In addition to the Dexela detector, a high pitch (50 μm), thin (150 μm) scintillator CMOS/CsI flat panel detector (C7921CA-09, Hamamatsu Corporation, Hamamatsu City, Japan) and a widelymore » used low pitch (194 μm), thick (600 μm) scintillator aSi/CsI flat panel detector (PaxScan 4030CB, Varian Medical Systems) were also used in scanning for comparison. The images were independently reviewed by six readers (imaging physicists). The MC visibility was quantified as the fraction of visible MCs and measured as a function of the estimated mean glandular dose (MGD) level for various MC sizes and detectors. The modulation transfer functions (MTFs) and detective quantum efficiencies (DQEs) were also measured and compared for the three detectors used.Results: The authors have demonstrated that the use of a high pitch (75 μm) CMOS detector coupled with a thick (500 μm) CsI scintillator helped make the smaller 150–160, 160–180, and 180–200 μm MC groups more visible at MGDs up to 10.8, 9, and 10.8 mGy, respectively. It also made the larger 200–212 and 212–224 μm MC groups more visible at MGDs up to 7.2 mGy. No performance improvement was observed for 224–250 μm or larger size groups. With the higher spatial resolution of the Dexela detector based system, the apparent dimensions and shapes of MCs were more accurately rendered. The results show that with the aforementioned detector, a 73% visibility could be achieved in imaging 160–180 μm MCs as compared to 28% visibility achieved by the low pitch (194 μm) aSi/CsI flat panel detector. The measurements confirm that the Hamamatsu detector has the highest MTF, followed by the Dexel detector, and then the Varian detector. However, the Dexela detector, with its thick (500 μm) CsI scintillator and low noise level, has the highest DQE at all frequencies, followed by the Varian detector, and then the Hamamatsu detector. The findings on the MC visibility correlated well with the differences in MTFs, noise power spectra, and DQEs measured for these three detectors.Conclusions: The authors have demonstrated that the use of the CMOS type Dexela detector with its high pitch (75 μm) and thick (500 μm) CsI scintillator could help improve the MC visibility. However, the improvement depended on the exposure level and the MC size. For imaging larger MCs or scanning at high exposure levels, there was little advantage in using the Dexela detector as compared to the aSi type Varian detector. These findings correlate well with the higher measured DQEs of the Dexela detector, especially at higher frequencies.« less

Cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS flat panel detector: Visibility of simulated microcalcifications

PubMed Central

Shen, Youtao; Zhong, Yuncheng; Lai, Chao-Jen; Wang, Tianpeng; Shaw, Chris C.

2013-01-01

Purpose: To measure and investigate the improvement of microcalcification (MC) visibility in cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS/CsI flat panel detector (Dexela 2923, Perkin Elmer). Methods: Aluminum wires and calcium carbonate grains of various sizes were embedded in a paraffin cylinder to simulate imaging of calcifications in a breast. Phantoms were imaged with a benchtop experimental cone beam CT system at various exposure levels. In addition to the Dexela detector, a high pitch (50 μm), thin (150 μm) scintillator CMOS/CsI flat panel detector (C7921CA-09, Hamamatsu Corporation, Hamamatsu City, Japan) and a widely used low pitch (194 μm), thick (600 μm) scintillator aSi/CsI flat panel detector (PaxScan 4030CB, Varian Medical Systems) were also used in scanning for comparison. The images were independently reviewed by six readers (imaging physicists). The MC visibility was quantified as the fraction of visible MCs and measured as a function of the estimated mean glandular dose (MGD) level for various MC sizes and detectors. The modulation transfer functions (MTFs) and detective quantum efficiencies (DQEs) were also measured and compared for the three detectors used. Results: The authors have demonstrated that the use of a high pitch (75 μm) CMOS detector coupled with a thick (500 μm) CsI scintillator helped make the smaller 150–160, 160–180, and 180–200 μm MC groups more visible at MGDs up to 10.8, 9, and 10.8 mGy, respectively. It also made the larger 200–212 and 212–224 μm MC groups more visible at MGDs up to 7.2 mGy. No performance improvement was observed for 224–250 μm or larger size groups. With the higher spatial resolution of the Dexela detector based system, the apparent dimensions and shapes of MCs were more accurately rendered. The results show that with the aforementioned detector, a 73% visibility could be achieved in imaging 160–180 μm MCs as compared to 28% visibility achieved by the low pitch (194 μm) aSi/CsI flat panel detector. The measurements confirm that the Hamamatsu detector has the highest MTF, followed by the Dexel detector, and then the Varian detector. However, the Dexela detector, with its thick (500 μm) CsI scintillator and low noise level, has the highest DQE at all frequencies, followed by the Varian detector, and then the Hamamatsu detector. The findings on the MC visibility correlated well with the differences in MTFs, noise power spectra, and DQEs measured for these three detectors. Conclusions: The authors have demonstrated that the use of the CMOS type Dexela detector with its high pitch (75 μm) and thick (500 μm) CsI scintillator could help improve the MC visibility. However, the improvement depended on the exposure level and the MC size. For imaging larger MCs or scanning at high exposure levels, there was little advantage in using the Dexela detector as compared to the aSi type Varian detector. These findings correlate well with the higher measured DQEs of the Dexela detector, especially at higher frequencies. PMID:24089917

Cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS flat panel detector: visibility of simulated microcalcifications.

PubMed

Shen, Youtao; Zhong, Yuncheng; Lai, Chao-Jen; Wang, Tianpeng; Shaw, Chris C

2013-10-01

To measure and investigate the improvement of microcalcification (MC) visibility in cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS/CsI flat panel detector (Dexela 2923, Perkin Elmer). Aluminum wires and calcium carbonate grains of various sizes were embedded in a paraffin cylinder to simulate imaging of calcifications in a breast. Phantoms were imaged with a benchtop experimental cone beam CT system at various exposure levels. In addition to the Dexela detector, a high pitch (50 μm), thin (150 μm) scintillator CMOS/CsI flat panel detector (C7921CA-09, Hamamatsu Corporation, Hamamatsu City, Japan) and a widely used low pitch (194 μm), thick (600 μm) scintillator aSi/CsI flat panel detector (PaxScan 4030CB, Varian Medical Systems) were also used in scanning for comparison. The images were independently reviewed by six readers (imaging physicists). The MC visibility was quantified as the fraction of visible MCs and measured as a function of the estimated mean glandular dose (MGD) level for various MC sizes and detectors. The modulation transfer functions (MTFs) and detective quantum efficiencies (DQEs) were also measured and compared for the three detectors used. The authors have demonstrated that the use of a high pitch (75 μm) CMOS detector coupled with a thick (500 μm) CsI scintillator helped make the smaller 150-160, 160-180, and 180-200 μm MC groups more visible at MGDs up to 10.8, 9, and 10.8 mGy, respectively. It also made the larger 200-212 and 212-224 μm MC groups more visible at MGDs up to 7.2 mGy. No performance improvement was observed for 224-250 μm or larger size groups. With the higher spatial resolution of the Dexela detector based system, the apparent dimensions and shapes of MCs were more accurately rendered. The results show that with the aforementioned detector, a 73% visibility could be achieved in imaging 160-180 μm MCs as compared to 28% visibility achieved by the low pitch (194 μm) aSi/CsI flat panel detector. The measurements confirm that the Hamamatsu detector has the highest MTF, followed by the Dexel detector, and then the Varian detector. However, the Dexela detector, with its thick (500 μm) CsI scintillator and low noise level, has the highest DQE at all frequencies, followed by the Varian detector, and then the Hamamatsu detector. The findings on the MC visibility correlated well with the differences in MTFs, noise power spectra, and DQEs measured for these three detectors. The authors have demonstrated that the use of the CMOS type Dexela detector with its high pitch (75 μm) and thick (500 μm) CsI scintillator could help improve the MC visibility. However, the improvement depended on the exposure level and the MC size. For imaging larger MCs or scanning at high exposure levels, there was little advantage in using the Dexela detector as compared to the aSi type Varian detector. These findings correlate well with the higher measured DQEs of the Dexela detector, especially at higher frequencies.

Assessment of a hybrid finite element-transfer matrix model for flat structures with homogeneous acoustic treatments.

PubMed

Alimonti, Luca; Atalla, Noureddine; Berry, Alain; Sgard, Franck

2014-05-01

Modeling complex vibroacoustic systems including poroelastic materials using finite element based methods can be unfeasible for practical applications. For this reason, analytical approaches such as the transfer matrix method are often preferred to obtain a quick estimation of the vibroacoustic parameters. However, the strong assumptions inherent within the transfer matrix method lead to a lack of accuracy in the description of the geometry of the system. As a result, the transfer matrix method is inherently limited to the high frequency range. Nowadays, hybrid substructuring procedures have become quite popular. Indeed, different modeling techniques are typically sought to describe complex vibroacoustic systems over the widest possible frequency range. As a result, the flexibility and accuracy of the finite element method and the efficiency of the transfer matrix method could be coupled in a hybrid technique to obtain a reduction of the computational burden. In this work, a hybrid methodology is proposed. The performances of the method in predicting the vibroacoutic indicators of flat structures with attached homogeneous acoustic treatments are assessed. The results prove that, under certain conditions, the hybrid model allows for a reduction of the computational effort while preserving enough accuracy with respect to the full finite element solution.

Thermographic imaging for high-temperature composite materials: A defect detection study

NASA Technical Reports Server (NTRS)

Roth, Don J.; Bodis, James R.; Bishop, Chip

1995-01-01

The ability of a thermographic imaging technique for detecting flat-bottom hole defects of various diameters and depths was evaluated in four composite systems (two types of ceramic matrix composites, one metal matrix composite, and one polymer matrix composite) of interest as high-temperature structural materials. The holes ranged from 1 to 13 mm in diameter and 0.1 to 2.5 mm in depth in samples approximately 2-3 mm thick. The thermographic imaging system utilized a scanning mirror optical system and infrared (IR) focusing lens in conjunction with a mercury cadmium telluride infrared detector element to obtain high resolution infrared images. High intensity flash lamps located on the same side as the infrared camera were used to heat the samples. After heating, up to 30 images were sequentially acquired at 70-150 msec intervals. Limits of detectability based on depth and diameter of the flat-bottom holes were defined for each composite material. Ultrasonic and radiographic images of the samples were obtained and compared with the thermographic images.

Flat Urothelial Lesions With Atypia: Interobserver Concordance and Added Value of Immunohistochemical Profiling.

PubMed

Lawless, Margaret E; Tretiakova, Maria S; True, Lawrence D; Vakar-Lopez, Funda

2018-03-01

Distinguishing urothelial carcinoma in situ (CIS) from other flat lesions of the urinary bladder with cytologic atypia is critically important for the management of patients with bladder neoplasia. However, there is high interpathologist variability in making these distinctions. The aim of this study is to assess interobserver agreement between general and specialized genitourinary pathologists, and to compare these diagnoses with those rendered after an immunohistochemical panel is performed. We hypothesized that addition of a set of immunohistochemical stains would reduce the number of cases classified within intermediate categories of atypia of uncertain significance and low-grade dysplasia. Two genitourinary pathologists independently assessed haematoxylin and eosin (H&E)-stained sections of 127 bladder biopsies from each of the 4 International Society of Urological Pathology/World Health Organization categories of flat lesions diagnosed by general pathologists. A subset of biopsies from 49 patients was reassessed after staining with a 3-antibody panel (CD44, CK20, and p53) and the results were correlated with patient follow-up. Based on these immunohistochemistry (IHC) stains, 26 cases (53.1%) were recategorized. Of most clinical importance, 5 of 27 cases (18.5%) originally diagnosed as either atypia of uncertain significance or low-grade dysplasia were recategorized as CIS, and recurrent disease was identified on subsequent biopsies. None of the 10 cases diagnosed as CIS based on H&E stains were recategorized. This triad of IHC stains can improve the precision of pathologic diagnosis of histologically atypical urothelial lesions of flat bladder mucosa. We recommend that pathologists apply this set of IHC stains to such lesions they find problematic based on H&E stains.

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.

Effects of Blank Curvature and Tool Conditions on the Spring Back of Thin Sheet Panel Formed through Local Embossing and Edge L-Bending

NASA Astrophysics Data System (ADS)

Park, Keecheol; Park, Jongyoun; Nam, Jaebok

2011-08-01

Due to the application of thinner sheet steels, the stamped panels in the forming process, generally, are severely distorted. The wavy shape of embossed panel finally converted to residual stress embedded in the panel at final forming (edge L-bending) and it is known as the cause of twisting and oil canning of spring backed panel. Another important source of stamped shape deviation is the curvature of blank. The effects of blank curvature on the shape defects (panel curvature and twisting) after stamping were investigated from defective panel analysis, model experiment and stamping simulation. And the effect of tool conditions (BHF and bead height change) on spring backed shape of real TV bottom chassis were studied. The initial curvature of blank was remained in the flat area of stamped panels as width directional curvature. It converted from length direction curvature of blank. The curvature of initial blank reduced the wavy shape after local emboss forming, but twisting after edge L-bending was increased at large blank curvature cases. The effects of emboss forming conditions, the forming heights and blank holding force were studied and it was found that the wavy shape of stamped sheet was rapidly changed although the forming conditions altered very small amount.

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.

Extraction and Inhibition of Enzymatic Activity of Botulinum Neurotoxins/A1, /A2, and /A3 by a Panel of Monoclonal Anti-BoNT/A Antibodies

DTIC Science & Technology

2009-04-01

triplicate and results were averaged. MS Detection A master mix was created consisting of 9 parts matrix solution (alpha-cyano-4-hydroxy cinnamic acid ...thus, do not inhibit the catalytic activity. Another feature of BoNT/A is that it exhibits genetic and amino acid variance within the toxin type, or...less amino acid variance [23] and this variance has been reported to affect binding of the toxin to anti-BoNT/A mAbs [24]. For these reasons, it is

A novel scatter-matrix eigenvalues-based total variation (SMETV) regularization for medical image restoration

NASA Astrophysics Data System (ADS)

Huang, Zhenghua; Zhang, Tianxu; Deng, Lihua; Fang, Hao; Li, Qian

2015-12-01

Total variation(TV) based on regularization has been proven as a popular and effective model for image restoration, because of its ability of edge preserved. However, as the TV favors a piece-wise constant solution, the processing results in the flat regions of the image are easily produced "staircase effects", and the amplitude of the edges will be underestimated; the underlying cause of the problem is that the regularization parameter can not be changeable with spatial local information of image. In this paper, we propose a novel Scatter-matrix eigenvalues-based TV(SMETV) regularization with image blind restoration algorithm for deblurring medical images. The spatial information in different image regions is incorporated into regularization by using the edge indicator called difference eigenvalue to distinguish edges from flat areas. The proposed algorithm can effectively reduce the noise in flat regions as well as preserve the edge and detailed information. Moreover, it becomes more robust with the change of the regularization parameter. Extensive experiments demonstrate that the proposed approach produces results superior to most methods in both visual image quality and quantitative measures.

An Approximate Solution to the Plastic Indentation of Circular Sandwich Panels

NASA Astrophysics Data System (ADS)

Xie, Z.

2018-05-01

The plastic indentation response of circular sandwich panels loaded by the flat end of a cylinder is investigated employing a velocity field model. Using the principles of virtual velocities and minimum work, an expression for the indenter load in relation to the indenter displacement and displacement field of the deformed face sheet is derived. The analytical solutions obtained are in good agreement with those found by simulations using the ABAQUS code. The radial tensile strain of the deformed face sheet and the ratio of energy absorption rate of the core to that of the face sheet are discussed.

Verification and Demonstration for Transition of Nonhexavalent Chromium, Low-Volatile Organic Compound (VOC) Alternative Technologies to Replace DOD-P-15328 Wash Primer for Multimetal Applications

DTIC Science & Technology

2017-09-28

DTL-53030 at 1008 h Aluminum panels were run out to 1008 h of exposure in ASTM B117 testing. The results obtained can be seen in Table 13. At 1008...were scraped with a 2-inch flat blade putty knife after rating to unveil any previously unseen corrosion or delamination issues between the coating and...CRS primed with MIL-DTL-53022 after 80 cycles Although success is established at 40 cycles, the aluminum test panels were also run out to 80 cycles

Development and demonstration of manufacturing processes for fabricating graphite/LARC 160 polyimide structural elements

NASA Technical Reports Server (NTRS)

Frost, R. K.; Jones, J. S.; Dynes, P. J.; Wykes, D. H.

1981-01-01

The development and demonstration of manufacturing technologies for the structural application of Celion graphite/LARC-160 polyimide composite material is discussed. Process development and fabrication of demonstration components are discussed. Process development included establishing quality assurance of the basic composite material and processing, nondestructive inspection of fabricated components, developing processes for specific structural forms, and qualification of processes through mechanical testing. Demonstration components were fabricated. The demonstration components consisted of flat laminates, skin/stringer panels, honeycomb panels, chopped fiber compression moldings, and a technology demonstrator segment (TDS) representative of the space shuttle aft body flap.

76 FR 4534 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Adoption of Control...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-26

... interior panels, exterior siding, and tileboard. A typical flat wood coating facility applies stains and..., Volatile Organic Compounds from Specific Processes. This action affects facilities that apply stains and... these emission limits: lb VOC per gallon material (grams Surface coatings, inks, or adhesives applied to...

21 CFR Appendix B to Subpart B of... - Scope of Product Coverage

Code of Federal Regulations, 2010 CFR

2010-04-01

... Transducer ITX—Transducer, Ultrasonic, Diagnostic Diagnostic X-Ray Imaging Devices (except mammographic x-ray systems): RA 892.1600 Angiographic X-Ray System IZI—System, X-Ray, Angiographic RA 892.1650 Image-Intensified Fluoroscopic X-Ray System MQB—Solid State X-Ray Imager (Flat Panel/Digital Imager) JAA—System, X...

21 CFR Appendix B to Subpart B of... - Scope of Product Coverage

Code of Federal Regulations, 2011 CFR

2011-04-01

... Transducer ITX—Transducer, Ultrasonic, Diagnostic Diagnostic X-Ray Imaging Devices (except mammographic x-ray systems): RA 892.1600 Angiographic X-Ray System IZI—System, X-Ray, Angiographic RA 892.1650 Image-Intensified Fluoroscopic X-Ray System MQB—Solid State X-Ray Imager (Flat Panel/Digital Imager) JAA—System, X...

Transparent, conducting films based on metal/dielectric photonic band gaps

NASA Astrophysics Data System (ADS)

Bloemer, Mark J.; Scalora, Michael; D'Aguanno, G.; Bowden, Charles M.; Baglio, Salvatore; Sibilia, Concita; Centini, Marco; Bertolotti, Mario

1999-07-01

A transparent conductor has been developed based on 1D metal/dielectric photonic band gap structures. Laminated metal/dielectric filters containing 100 nm of silver have been fabricated with > 50% transmittance. Applications for transparent, conducting films include antennas embedded in windshields, electrodes on flat panel displays, electromagnetic shielding, and solar window panes.

75 FR 21197 - Approval and Promulgation of Implementation Plans; Implementation Plan Revision; State of New Jersey

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-23

...; asphalt pavement production plants; CTGs published in 2006: flat wood paneling, flexible packaging... new provisions that New Jersey designed to minimize emissions when a tank goes through a ``roof... approve them. Section 16.11 Asphalt Pavement Production Plants The New Jersey amendments to section 16.11...

Nondestructive test of regenerative chambers

NASA Technical Reports Server (NTRS)

Malone, G. A.; Stauffis, R.; Wood, R.

1972-01-01

Flat panels simulating internally cooled regenerative thrust chamber walls were fabricated by electroforming, brazing and diffusion bonding to evaluate the feasibility of nondestructive evaluation techniques to detect bonds of various strength integrities. Ultrasonics, holography, and acoustic emission were investigated and found to yield useful and informative data regarding the presence of bond defects in these structures.

The exact solution of shear-lag problems in flat panels and box beams assumed rigid in the transverse direction

NASA Technical Reports Server (NTRS)

Hildebrand, Francis B

1943-01-01

A mathematical procedure is herein developed for obtaining exact solutions of shear-lag problems in flat panels and box beams: the method is based on the assumption that the amount of stretching of the sheets in the direction perpendicular to the direction of essential normal stresses is negligible. Explicit solutions, including the treatment of cut-outs, are given for several cases and numerical results are presented in graphic and tabular form. The general theory is presented in a from which further solutions can be readily obtained. The extension of the theory to cover certain cases of non-uniform cross section is indicated. Although the solutions are obtained in terms of infinite series, the present developments differ from those previously given in that, in practical cases, the series usually converge so rapidly that sufficient accuracy is afforded by a small number of terms. Comparisons are made in several cases between the present results and the corresponding solutions obtained by approximate procedures devised by Reissner and by Kuhn and Chiarito.

Effect of gradual transition of substrate on performance of flat-panel air-cathode microbial fuel cells to treat domestic wastewater.

PubMed

Park, Younghyun; Park, Seonghwan; Nguyen, Van Khanh; Kim, Jung Rae; Kim, Hong Suck; Kim, Byung Goon; Yu, Jaecheul; Lee, Taeho

2017-02-01

In order to confirm the effects of the low conductivity and biodegradability of wastewater, flat-panel air-cathode microbial fuel cells (FA-MFCs) were operated by supplying substrates with different volume ratios of domestic wastewater mixed with an artificial medium: the artificial medium only, 25% wastewater, 50% wastewater, 75% wastewater, 100% of wastewater with 500mg-COD/L by adding acetate, and raw domestic wastewater (230mg-COD/L). With the increase of wastewater ratio, the maximum power density and organic removal efficiency decreased from 187 to 60W/m 3 and 51.5 to 37.4%, respectively, but the Coulombic efficiency was maintained in the range of 18.0-18.9%. The FA-MFCs could maintain their low internal resistances and overcome the decreasing conductivity. The acetate concentration was more important than the total organics for power production. This study suggests that the FA-MFC configuration has great applicability for practical applications when supplied by domestic wastewater with low conductivity and biodegradability. Copyright © 2016 Elsevier Ltd. All rights reserved.

Performance evaluation of a retrofit digital detector-based mammography system.

PubMed

Marshall, Nicholas W; van Ongeval, Chantal; Bosmans, Hilde

2016-02-01

A retrofit flat panel detector was integrated with a GE DMR+ analog mammography system and characterized using detective quantum efficiency (DQE). Technical system performance was evaluated using the European Guidelines protocol, followed by a limited evaluation of clinical image quality for 20 cases using image quality criteria in the European Guidelines. Optimal anode/filter selections were established using signal difference-to-noise ratio measurements. Only small differences in peak DQE were seen between the three anode/filter settings, with an average value of 0.53. For poly(methyl methacrylate) (PMMA) thicknesses above 60 mm, the Rh/Rh setting was the optimal anode/filter setting. The system required a mean glandular dose of 0.54 mGy at 30 kV Rh/Rh to reach the Acceptable gold thickness limit for 0.1 mm details. Imaging performance of the retrofit unit with the GE DMR+ is notably better than of powder based computed radiography systems and is comparable to current flat panel FFDM systems. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Imaging of the midpalatal suture in a porcine model: flat-panel volume computed tomography compared with multislice computed tomography.

PubMed

Hahn, Wolfram; Fricke-Zech, Susanne; Fialka-Fricke, Julia; Dullin, Christian; Zapf, Antonia; Gruber, Rudolf; Sennhenn-kirchner, Sabine; Kubein-Meesenburg, Dietmar; Sadat-Khonsari, Reza

2009-09-01

An investigation was conducted to compare the image quality of prototype flat-panel volume computed tomography (fpVCT) and multislice computed tomography (MSCT) of suture structures. Bone samples were taken from the midpalatal suture of 5 young (16 weeks) and 5 old (200 weeks) Sus scrofa domestica and fixed in formalin solution. An fpVCT prototype and an MSCT were used to obtain images of the specimens. The facial reformations were assessed by 4 observers using a 1 (excellent) to 5 (poor) rating scale for the weighted criteria visualization of the suture structure. A linear mixed model was used for statistical analysis. Results with P < .05 were considered to be statistically significant. The visualization of the suture of young specimens was significantly better than that of older animals (P < .001). The visualization of the suture with fpVCT was significantly better than that with MSCT (P < .001). Compared with MSCT, fpVCT produces superior results in the visualization of the midpalatal suture in a Sus scrofa domestica model.

Development of CT and 3D-CT Using Flat Panel Detector Based Real-Time Digital Radiography System

NASA Astrophysics Data System (ADS)

Ravindran, V. R.; Sreelakshmi, C.; Vibin, Vibin

2008-09-01

The application of Digital Radiography in the Nondestructive Evaluation (NDE) of space vehicle components is a recent development in India. A Real-time DR system based on amorphous silicon Flat Panel Detector has been developed for the NDE of solid rocket motors at Rocket Propellant Plant of VSSC in a few years back. The technique has been successfully established for the nondestructive evaluation of solid rocket motors. The DR images recorded for a few solid rocket specimens are presented in the paper. The Real-time DR system is capable of generating sufficient digital X-ray image data with object rotation for the CT image reconstruction. In this paper the indigenous development of CT imaging based on the Realtime DR system for solid rocket motor is presented. Studies are also carried out to generate 3D-CT image from a set of adjacent CT images of the rocket motor. The capability of revealing the spatial location and characterisation of defect is demonstrated by the CT and 3D-CT images generated.

A novel high resolution, high sensitivity SPECT detector for molecular imaging of cardiovascular diseases

NASA Astrophysics Data System (ADS)

Cusanno, F.; Argentieri, A.; Baiocchi, M.; Colilli, S.; Cisbani, E.; De Vincentis, G.; Fratoni, R.; Garibaldi, F.; Giuliani, F.; Gricia, M.; Lucentini, M.; Magliozzi, M. L.; Majewski, S.; Marano, G.; Musico, P.; Musumeci, M.; Santavenere, F.; Torrioli, S.; Tsui, B. M. W.; Vitelli, L.; Wang, Y.

2010-05-01

Cardiovascular diseases are the most common cause of death in western countries. Understanding the rupture of vulnerable atherosclerotic plaques and monitoring the effect of innovative therapies of heart failure is of fundamental importance. A flexible, high resolution, high sensitivity detector system for molecular imaging with radionuclides on small animal models has been designed for this aim. A prototype has been built using tungsten pinhole and LaBr3(Ce) scintillator coupled to Hamamatsu Flat Panel PMTs. Compact individual-channel readout has been designed, built and tested. Measurements with phantoms as well as pilot studies on mice have been performed, the results show that the myocardial perfusion in mice can be determined with sufficient precision. The detector will be improved replacing the Hamamatsu Flat Panel with Silicon Photomultipliers (SiPMs) to allow integration of the system with MRI scanners. Application of LaBr3(Ce) scintillator coupled to photosensor with high photon detection efficiency and excellent energy resolution will allow dual-label imaging to monitor simultaneously the cardiac perfusion and the molecular targets under investigation during the heart therapy.

Sharpening of field emitter tips using high-energy ions

DOEpatents

Musket, Ronald G.

1999-11-30

A process for sharpening arrays of field emitter tips of field emission cathodes, such as found in field-emission, flat-panel video displays. The process uses sputtering by high-energy (more than 30 keV) ions incident along or near the longitudinal axis of the field emitter to sharpen the emitter with a taper from the tip or top of the emitter down to the shank of the emitter. The process is particularly applicable to sharpening tips of emitters having cylindrical or similar (e.g., pyramidal) symmetry. The process will sharpen tips down to radii of less than 12 nm with an included angle of about 20 degrees. Because the ions are incident along or near the longitudinal axis of each emitter, the tips of gated arrays can be sharpened by high-energy ion beams rastered over the arrays using standard ion implantation equipment. While the process is particularly applicable for sharpening of arrays of field emitters in field-emission flat-panel displays, it can be effectively utilized in the fabrication of other vacuum microelectronic devices that rely on field emission of electrons.

Development of CT and 3D-CT Using Flat Panel Detector Based Real-Time Digital Radiography System

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

Ravindran, V. R.; Sreelakshmi, C.; Vibin

2008-09-26

The application of Digital Radiography in the Nondestructive Evaluation (NDE) of space vehicle components is a recent development in India. A Real-time DR system based on amorphous silicon Flat Panel Detector has been developed for the NDE of solid rocket motors at Rocket Propellant Plant of VSSC in a few years back. The technique has been successfully established for the nondestructive evaluation of solid rocket motors. The DR images recorded for a few solid rocket specimens are presented in the paper. The Real-time DR system is capable of generating sufficient digital X-ray image data with object rotation for the CTmore » image reconstruction. In this paper the indigenous development of CT imaging based on the Realtime DR system for solid rocket motor is presented. Studies are also carried out to generate 3D-CT image from a set of adjacent CT images of the rocket motor. The capability of revealing the spatial location and characterisation of defect is demonstrated by the CT and 3D-CT images generated.« less

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

NASA Technical Reports Server (NTRS)

Wooley, J. H.

1974-01-01

Fairing panels were fabricated to evaluate the fabrication characteristics and flight service performance of PRD-49 (Kevlar-49) a composite reinforcing material and to compare it with the fiberglass which is currently in use. Panel configurations were selected to evaluate the PRD-49 with two resin matrix materials in sandwich and solid laminate construction. Left and right hand versions of these configurations were installed on L-1011's which will accumulate approximately 3000 flight hours per year per aircraft. The direct substitution of PRD-49 for fiberglass produced a twenty-six percent weight reduction on the panel configurations. Examination of these panels revealed that there was no visible difference between the PRD-49 and adjacent fiberglass panels.

Analytical prediction of moisture absorption/desorption in resin matrix composites exposed to aircraft environments

NASA Technical Reports Server (NTRS)

Unnam, J.; Tenney, D. R.

1977-01-01

The moisture absorption/desorption behavior of resin matrix composites was mathematically modeled by classical diffusion theory using an effective diffusion coefficient. Good agreement was found between calculated moisture content and published data for T300/5208 graphite fiber reinforced epoxy matrix composite. Weather Bureau data for Langley Air Force Base and Norfolk, Va., were used to calculate the amount of moisture a T300/5208 composite panel would contain if exposed outdoors. Results obtained by using average monthly weather data for several high aircraft usage locations around the world suggest that, except for desert areas, geographical locations should have only minimal effect on the moisture absorption level reached in composites. Solar radiation data together with cloud and wind information were included in the analysis to estimate an effective temperature of the composite panel during ground exposure.

Issues on Fabrication and Evaluation of SiC/SiC Tubes With Various Fiber Architectures

NASA Technical Reports Server (NTRS)

Yun, H. M.; DiCarlo, J. A.; Fox, D. S.

2004-01-01

SiC/SiC engine components, high-modulus Sylramic-iBN SiC fiber tows were used to form nine different tubular architectural preforms with 13 mm (0.5 in.) inner diameter and lengths of approx. 75 and 230 mm (approx. 3 and approx, 9 in.). The thin-walled preforms were then coated with a BN interphase and densified with a hybrid SiC matrix using nearly the same process steps previously established for slurry-cast melt-infiltrated Sylramic-iBN/BN/SiC flat panels. The as-fabricated CMC tubes were microstructurally evaluated and tested for tensile hoop and flexural behavior, and some of the tubes were also tested in a low-pressure burner rig test with a high thru-thickness thermal gradient. To date, four general tube scale-up issues have been identified: greater CVI deposits on outer wall than inner wall; increased ply thickness and reduced fiber fraction; poor test standards for accurately determining the hoop strength of a small-diameter tube; and poor hoop strength for architectures with seams or ply ends. The underlying mechanisms and possible methods for their minimization are discussed.

X-ray light valve (XLV): a novel detectors' technology for digital mammography

NASA Astrophysics Data System (ADS)

Marcovici, Sorin; Sukhovatkin, Vlad; Oakham, Peter

2014-03-01

A novel method, based on X-ray Light Valve (XLV) technology, is proposed for making good image quality yet inexpensive flat panel detectors for digital mammography. The digital mammography markets, particularly in the developing countries, demand quality machines at substantially lower prices than the ones available today. Continuous pressure is applied on x-ray detectors' manufacturers to reduce the flat panel detectors' prices. XLV presents a unique opportunity to achieve the needed price - performance characteristics for direct conversion, x-ray detectors. The XLV based detectors combine the proven, superior, spatial resolution of a-Se with the simplicity and low cost of liquid crystals and optical scanning. The x-ray quanta absorbed by a 200 μm a-Se produce electron - hole pairs that move under an electric field to the top and bottom of a-Se layer. This 2D charge distribution creates at the interface with the liquid crystals a continuous (analog) charge image corresponding to the impinging radiation's information. Under the influence of local electrical charges next to them, the liquid crystals twist proportionally to the charges and vary their light reflectivity. A scanning light source illuminates the liquid crystals while an associated, pixilated photo-detector, having a 42 μm pixel size, captures the light reflected by the liquid crystals and converts it in16 bit words that are transmitted to the machine for image processing and display. The paper will describe a novel XLV, 25 cm x 30 cm, flat panel detector structure and its underlying physics as well as its preliminary performance measured on several engineering prototypes. In particular, the paper will present the results of measuring XLV detectors' DQE, MTF, dynamic range, low contrast resolution and dynamic behavior. Finally, the paper will introduce the new, low cost, XLV detector based, digital mammography machine under development at XLV Diagnostics Inc.

Biomarkers of hepatic fibrosis, fibrogenesis and genetic pre-disposition pending between fiction and reality

PubMed Central

Gressner, OA; Weiskirchen, R; Gressner, AM

2007-01-01

Abstract Fibrosis is a frequent, life-threatening complication of most chronic liver diseases. Despite major achievements in the understanding of its pathogenesis, the translation of this knowledge into clinical practice is still limited. In particular, non-invasive and reliable (serum-) biomarkers indicating the activity of fibrogenesis are scarce. Class I biomarkers are defined as serum components having a direct relation to the mechanism of fibrogenesis, either as secreted matrix-related components of activated hepatic stellate cells and fibroblasts or as mediators of extracellular matrix (ECM) synthesis or turnover. They reflect primarily the activity of the fibrogenic process. Many of them, however, proved to be disappointing with regard to sensitivity and speci-ficity. Up to now hyaluronan turned out to be the relative best type I serum marker. Class II biomarkers comprise in general rather simple standard laboratory tests, which are grouped into panels. They fulfil most criteria for detection and staging of fibrosis and to a lesser extent grading of fibrogenic activity. More than 20 scores are currently available, among which Fibrotest™ is the most popular one. However, the diagnostic use of many of these scores is still limited and standardization of the assays is only partially realized. Combining of panel markers in sequential algorithms might increase their diagnostic validity. The translation of genetic pre-disposition biomarkers into clinical practice has not yet started, but some polymorphisms indicate a link to progression and outcome of fibrogenesis. Parallel to serum markers non-invasive physical techniques, for example, transient elastography, are developed, which can be combined with serum tests and profiling of serum proteins and glycans. PMID:17979881

Nonlinear acoustics and honeycomb materials

NASA Astrophysics Data System (ADS)

Thompson, D. O.

2012-05-01

The scope of research activity that Bruce Thompson embraced was very large. In this talk three different research topics that the author shared with Bruce are reviewed. They represent Bruce's introduction to NDE and include nonlinear acoustics, nondestructive measurements of adhesive bond strengths in honeycomb panels, and studies of flexural wave dispersion in honeycomb materials. In the first of these, four harmonics of a 30 Mhz finite amplitude wave were measured for both fused silica and aluminum single crystals with varying lengths and amounts of cold work using a capacity microphone with heterodyne receiver with a flat frequency response from 30 to 250 Mhz. The results for fused silica with no dislocation structure could be described by a model due to Fubini, originally developed for gases, that depends upon only the second and third order elastic constants and not the fourth and higher order constants. The same was not true for the aluminum with dislocation structures. These results raised some questions about models for harmonic generation in materials with dislocations. In the second topic, experiments were made to determine the adhesive bond strengths of honeycomb panels using the vibrational response of the panels (Chladni figures). The results showed that both the damping characteristics of panel vibrations as a whole and velocity of propagation of elastic waves that travel along the surface and sample the bondline can be correlated with destructively determined bond strengths. Finally, the phase velocity of flexural waves traveling along a 1-inch honeycomb sandwich panel was determined from 170 Hz to 50 Khz, ranging from 2.2×104 cm/sec at the low end to 1.18×105 cm/sec at 40 Khz. The dispersion arises from the finite thickness of the panel and agreed with the results of continuum models for the honeycomb. Above 40 Khz, this was not the case. The paper concludes with a tribute to Bruce for his many wonderful contributions and lessons beyond his technical legacy for all of us.

Densification of a-IGZO with low-temperature annealing for flexible electronics applications

NASA Astrophysics Data System (ADS)

Troughton, J. G.; Downs, P.; Price, R.; Atkinson, D.

2017-01-01

Amorphous InGaZnO (a-IGZO) thin-film transistors are a leading contender for active channel materials in next generation flat panel displays and flexible electronics. Improved electronic functionality has been linked to the increased density of a-IGZO, and while much work has looked at high-temperature processes, studies at temperatures compatible with flexible substrates are needed. Here, compositional and structural analyses show that short term, low-temperature annealing (<6 h) can increase the density of sputtered a-IGZO by up to 5.6% for temperatures below 300 °C, which is expected to improve the transistor performance, while annealing for longer times leads to a subsequent decrease in density due to oxygen absorption.

Optimization of Elastically Tailored Tow-Placed Plates with Holes

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.; Tatting, Brian F.; Guerdal, Zafer

2003-01-01

Elastic stiffness tailoring of laminated composite panels by allowing the fibers to curve within the plane of the laminate is a design concept that has been demonstrated to be both beneficial and practical. The objective of the present paper is to demonstrate the effectiveness of stiffness tailoring through the use of curvilinear fibers to reduce stress concentrations around the hole and improve the load carrying capability of panels. Preliminary panel designs that are to be manufactured and tested were determined through design studies for flat plates without holes under axial compression using an optimization program. These candidate designs were then analyzed with finite element models that accurately reflect the test conditions and geometries in order to decide upon the final designs for manufacture and testing. An advanced tow-placement machine is used to manufacture the test panels with varying fiber orientation angles. A total of six large panels measuring three feet by six feet, each of which is used to produce four specimens with or without holes, are fabricated. The panels were machined into specimens with holes and tested at NASA Langley Research Center. Buckling response and failure of panels without holes and with two different hole dimensions are presented. Buckling and failure loads of tow-steered specimens are significantly greater than the buckling and failure loads of traditional straight-fiber specimens.

Optimization of Blended Wing Body Composite Panels Using Both NASTRAN and Genetic Algorithm

NASA Technical Reports Server (NTRS)

Lovejoy, Andrew E.

2006-01-01

The blended wing body (BWB) is a concept that has been investigated for improving the performance of transport aircraft. A trade study was conducted by evaluating four regions from a BWB design characterized by three fuselage bays and a 400,000 lb. gross take-off weight (GTW). This report describes the structural optimization of these regions via computational analysis and compares them to the baseline designs of the same construction. The identified regions were simplified for use in the optimization. The regions were represented by flat panels having appropriate classical boundary conditions and uniform force resultants along the panel edges. Panel-edge tractions and internal pressure values applied during the study were those determined by nonlinear NASTRAN analyses. Only one load case was considered in the optimization analysis for each panel region. Optimization was accomplished using both NASTRAN solution 200 and Genetic Algorithm (GA), with constraints imposed on stress, buckling, and minimum thicknesses. The NASTRAN optimization analyses often resulted in infeasible solutions due to violation of the constraints, whereas the GA enforced satisfaction of the constraints and, therefore, always ensured a feasible solution. However, both optimization methods encountered difficulties when the number of design variables was increased. In general, the optimized panels weighed less than the comparable baseline panels.

Luminance uniformity compensation for OLED panels based on FPGA

NASA Astrophysics Data System (ADS)

Ou, Peng; Yang, Gang; Jiang, Quan; Yu, Jun-Sheng; Wu, Qi-Peng; Shang, Fu-Hai; Yin, Wei; Wang, Jun; Zhong, Jian; Luo, Kai-Jun

2009-09-01

Aiming at the problem of luminance uniformity for organic lighting-emitting diode (OLED) panels, a new brightness calculating method based on bilinear interpolation is proposed. The irradiance time of each pixel reaching the same luminance is figured out by Matlab. Adopting the 64×32-pixel, single color and passive matrix OLED panel as adjusting luminance uniformity panel, a new circuit compensating scheme based on FPGA is designed. VHDL is used to make each pixel’s irradiance time in one frame period written in program. The irradiance brightness is controlled by changing its irradiance time, and finally, luminance compensation of the panel is realized. The simulation result indicates that the design is reasonable.

[Development, physiology, and cell activity of bone].

PubMed

de Baat, P; Heijboer, M P; de Baat, C

2005-07-01

Bones are of crucial importance for the human body, providing skeletal support, serving as a home for the formation of haematopoietic cells, and reservoiring calcium and phosphate. Long bones develop by endochondral ossification. Flat bones develop by intramembranous ossification. Bone tissue contains hydroxyapatite and various extracellular proteins, producing bone matrix. Two biological mechanisms, determining the strength of bone, are modelling and remodelling. Modelling can change bone shape and size through bone formation by osteoblasts at some sites and through bone destruction by osteoclasts at other sites. Remodelling is bone turnover, also performed by osteoclasts and osteoblasts. The processes of modelling and remodelling are induced by mechanical loads, predominantly muscle loads. Osteoblasts develop from mesenchymal stem cells. Many stimulating factors are known to activate the differentiation. Mature osteoblasts synthesize bone matrix and may further differentiate into osteocytes. Osteocytes maintain structural bone integrity and allow bone to adapt to any mechanical and chemical stimulus. Osteoclasts derive from haematopoietic stem cells. A number of transcription and growth factors have been identified essential for osteoclast differentiation and function. Finally, there is a complex interaction between osteoblasts and osteoclasts. Bone destruction starts by attachment of osteoclasts to the bone surface. Following this, osteoclasts undergo specific morphological changes. The process of bone destruction starts by acid dissolution of hydroxyapatite. After that osteoclasts start to destruct the organic matrix.

Impact behavior of basalt/epoxy composite: Comparison between flat and twill fabric

NASA Astrophysics Data System (ADS)

Papa, I.; Ricciardi, M. R.; Antonucci, V.; Langella, A.; Lopresto, V.

2018-05-01

Two types of basalt fibre reinforced epoxy laminates were realized by overlapping flat and twill woven basalt fabrics by resin infusion. Rectangular specimens, cut from the panels were impacted at penetration and at increasing energy values, to investigate the damage onset and propagation. A non-destructive technique, Ultrasound testing (UT), was adopted to investigate the internal damage. Despite the difficulties to obtain information by UT method due to the high amount of signal absorbed, the technique, properly calibrated, proved to be very useful in providing information about the presence, the shape and the extent of the delaminations. The results were compared at the aim to investigate the effect of the fiber architecture (textile). The experimental results indicate a similar impact behavior between basalt flat and twill composites but in the case of the twill a minor delaminated area was detected, even if a higher absorbed energy was recorded

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.

Iodine 125 Imaging in Mice Using NaI(Tl)/Flat Panel PMT Integral Assembly

NASA Astrophysics Data System (ADS)

Cinti, M. N.; Majewski, S.; Williams, M. B.; Bachmann, C.; Cominelli, F.; Kundu, B. K.; Stolin, A.; Popov, V.; Welch, B. L.; De Vincentis, G.; Bennati, P.; Betti, M.; Ridolfi, S.; Pani, R.

2007-06-01

Radiolabeled agents that bind to specific receptors have shown great promise in diagnosing and characterizing tumor cell biology. In vivo imaging of gene transcription and protein expression represents an other area of interest. The radioisotope I is commercially available as a label for molecular probes and utilized by researchers in small animal studies. We propose an advanced imaging detector based on planar NaI(T1) integral assembly with a Hamamatsu Flat Panel Photomultiplier (MA-PMT) representing one of the best trade-offs between spatial resolution and detection efficiency. We characterized the imaging performances of this planar detector, in comparison with a gamma camera based on a pixellated scintillator. We also tested the in-vivo image capability by acquiring images of mice as a part of a study of inflammatory bowel disease (IBD). In this study, four 25g mice with an IBD-like phenotype (SAMP1/YitFc) were injected with 375, 125, 60 and 30 muCi of I-labelled antibody against mucosal vascular addressin cell adhesion molecule (MAdCAM-1), which is up-regulated in the presence of inflammation. Two mice without bowel inflammation were injected with 150 and 60 muCi of the labeled anti-MAdCAM-1 antibody as controls. To better evaluate the performances of the integral assembly detector, we also acquired mice images with a dual modality (X and Gamma Ray) camera dedicated for small animal imaging. The results coming from this new detector are considerable: images of SAMP1/YitFc injected with 30 muCi activity show inflammation throughout the intestinal tract, with the disease very well defined at two hours post-injection.

Dual-gate photo thin-film transistor: a “smart” pixel for high- resolution and low-dose X-ray imaging

NASA Astrophysics Data System (ADS)

Wang, Kai; Ou, Hai; Chen, Jun

2015-06-01

Since its emergence a decade ago, amorphous silicon flat panel X-ray detector has established itself as a ubiquitous platform for an array of digital radiography modalities. The fundamental building block of a flat panel detector is called a pixel. In all current pixel architectures, sensing, storage, and readout are unanimously kept separate, inevitably compromising resolution by increasing pixel size. To address this issue, we hereby propose a “smart” pixel architecture where the aforementioned three components are combined in a single dual-gate photo thin-film transistor (TFT). In other words, the dual-gate photo TFT itself functions as a sensor, a storage capacitor, and a switch concurrently. Additionally, by harnessing the amplification effect of such a thin-film transistor, we for the first time created a single-transistor active pixel sensor. The proof-of-concept device had a W/L ratio of 250μm/20μm and was fabricated using a simple five-mask photolithography process, where a 130nm transparent ITO was used as the top photo gate, and a 200nm amorphous silicon as the absorbing channel layer. The preliminary results demonstrated that the photocurrent had been increased by four orders of magnitude due to light-induced threshold voltage shift in the sub-threshold region. The device sensitivity could be simply tuned by photo gate bias to specifically target low-level light detection. The dependence of threshold voltage on light illumination indicated that a dynamic range of at least 80dB could be achieved. The "smart" pixel technology holds tremendous promise for developing high-resolution and low-dose X-ray imaging and may potentially lower the cancer risk imposed by radiation, especially among paediatric patients.

Potential of a New Lunar Surface Radiator Concept for Hot Lunar Thermal Environments

NASA Technical Reports Server (NTRS)

Ochoa, Dustin A.; Vogel, Matthew R.; Trevino, Luis A.; Stephan, Ryan A.

2008-01-01

The optimum radiator configuration in hot lunar thermal environments is one in which the radiator is parallel to the ground and has no view to the hot lunar surface. However, typical spacecraft configurations have limited real estate available for top-mounted radiators, resulting in a desire to use the spacecraft s vertically oriented sides. Vertically oriented, flat panel radiators will have a large view factor to the lunar surface, and thus will be subjected to significant incident lunar infrared heat. Consequently, radiator fluid temperatures will need to exceed approx.325 K (assuming standard spacecraft radiator optical properties) in order to provide positive heat rejection at lunar noon. Such temperatures are too high for crewed spacecraft applications in which a heat pump is to be avoided. A recent study of vertically oriented radiator configurations subjected to lunar noon thermal environments led to the discovery of a novel radiator concept that yielded positive heat rejection at lower fluid temperatures. This radiator configuration, called the Upright Lunar Terrain Radiator Assembly (ULTRA), has exhibited superior performance to all previously analyzed concepts in terms of heat rejection in the lunar noon thermal environment. A key benefit of the ULTRA is the absence of louvers or other moving parts and its simple geometry. Analysis of the ULTRA for a lunar extravehicular activity (EVA) portable life support system (PLSS) is shown to provide moderate heat rejection, on average, at all solar incident angles assuming an average radiator temperature of 294 K, whereas prior concepts exhibited insignificant heat rejection or heat absorption at higher incident angles. The performance of the ULTRA for a lunar lander is also discussed and compared to the performance of a vertically oriented, flat panel radiator at various lunar latitudes.

Design of two-way reversible bending actuator based on a shape memory alloy/shape memory polymer composite

NASA Astrophysics Data System (ADS)

Taya, Minoru; Liang, Yuanchang; Namli, Onur C.; Tamagawa, Hirohisa; Howie, Tucker

2013-10-01

The design of a reversible bending actuator based on a SMA/SMP composite is presented. The SMA/SMP composite is made of SMA NiTi wires with a bent ‘U’-shape in the austenite phase embedded in an epoxy SMP matrix which has a memorized flat shape. The bending motion is caused by heating the composite above TAf to activate the NiTi recovery. Upon cooling, the softening from the austenite to R-phase transformation results in a relaxation of the composite towards its original flat shape. In the three-point bending measurement the composite was able to exhibit a reversible deflection of 1.3 mm on a support with a 10 mm span. In addition, a material model for predicting the composite’s deflection is presented and predicts the experimental results reasonably well. The model also estimates the in-plane internal force and the degree of the SMA phase transformation.

Innovative Ballasted Flat Roof Solar PV Racking System

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

Peek, Richard T.

2014-12-15

The objective of this project was to reduce the cost of racking for PV solar on flat commercial rooftops. Cost reductions would come from both labor savings and material savings related to the installation process. The rack would need to accommodate the majority of modules available on the market. Cascade Engineering has a long history of converting traditional metal type applications over to plastic. Injection molding of plastics have numerous advantages including selection of resin for the application, placing the material exactly where it is needed, designing in features that will speed up the installation process, and weight reduction ofmore » the array. A plastic rack would need to meet the requirements of UL2703, Mounting systems, mounting devices, clamping/retention devices, and ground lugs for use with flat-plate photovoltaic modules and panels. Comparing original data to the end of project racking design, racking material costs were reduced 50% and labor costs reduced 64%. The racking product accommodates all 60 and 72 cell panels on the market, meets UL2703 requirements, contributes only 1.3 pounds per square foot of weight to the array, requires little ballast to secure the array, automatically grounds the module when the module is secured, stacks/nests well for shipping/fewer lifts to the roof, provides integrated wire routing, allows water to drain on the roof, and accommodates various seismic roof connections. Project goals were achieved as noted in the original funding application.« less

Design and construction of a photobioreactor for hydrogen production, including status in the field.

PubMed

Skjånes, Kari; Andersen, Uno; Heidorn, Thorsten; Borgvang, Stig A

Several species of microalgae and phototrophic bacteria are able to produce hydrogen under certain conditions. A range of different photobioreactor systems have been used by different research groups for lab-scale hydrogen production experiments, and some few attempts have been made to upscale the hydrogen production process. Even though a photobioreactor system for hydrogen production does require special construction properties (e.g., hydrogen tight, mixing by other means than bubbling with air), only very few attempts have been made to design photobioreactors specifically for the purpose of hydrogen production. We have constructed a flat panel photobioreactor system that can be used in two modes: either for the cultivation of phototrophic microorganisms (upright and bubbling) or for the production of hydrogen or other anaerobic products (mixing by "rocking motion"). Special emphasis has been taken to avoid any hydrogen leakages, both by means of constructional and material choices. The flat plate photobioreactor system is controlled by a custom-built control system that can log and control temperature, pH, and optical density and additionally log the amount of produced gas and dissolved oxygen concentration. This paper summarizes the status in the field of photobioreactors for hydrogen production and describes in detail the design and construction of a purpose-built flat panel photobioreactor system, optimized for hydrogen production in terms of structural functionality, durability, performance, and selection of materials. The motivations for the choices made during the design process and advantages/disadvantages of previous designs are discussed.

Acoustic fatigue and sound transmission characteristics of a ram composite panel design

NASA Technical Reports Server (NTRS)

Cockburn, J. A.; Chang, K. Y.; Kao, G. C.

1972-01-01

An experimental study to determine the acoustic fatigue characteristics of a flat multi-layered structural panel is described. The test panel represented a proposed design for the outer skin of a research application module to be housed within the space shuttle orbiter vehicle. The test specimen was mounted in one wall of the Wyle 100,000 cu ft reverberation room and exposed to a broadband acoustic environment having an overall level of 145 db. The test panel was exposed to nine separate applications of the acoustic environment, each application consisting of 250 seconds duration. Upon completion of the ninth test run, the specimen was exposed to a simulated micrometeoroid impact near the panel center. One additional test run of 250 seconds duration was then performed to complete the overall simulation of 50 flight missions. The experimental results show that no significant fatigue damage occurred until the test specimen was exposed to a simulated micrometeoroid impact. The intermediate foam layer forming the core of the test specimen suffered considerable damage due to this impact, causing a marked variation in the dynamic characteristics of the overall test panel. During the final application of the acoustic environment, the strain and acceleration response spectra showed considerable variation from those spectra obtained prior to impact of the panel. Fatigue damage from acoustic loading however, was limited to partial de-bonding around the edges of the composite panel.

Properties Of Carbon/Carbon and Carbon/Phenolic Composites

NASA Technical Reports Server (NTRS)

Mathis, John R.; Canfield, A. R.

1993-01-01

Report presents data on physical properties of carbon-fiber-reinforced carbon-matrix and phenolic-matrix composite materials. Based on tests conducted on panels, cylinders, blocks, and formed parts. Data used by designers to analyze thermal-response and stress levels and develop structural systems ensuring high reliability at minimum weight.

Out-of-autoclave manufacturing of a stiffened thermoplastic carbon fibre PEEK panel

NASA Astrophysics Data System (ADS)

Flanagan, M.; Goggins, J.; Doyle, A.; Weafer, B.; Ward, M.; Bizeul, M.; Canavan, R.; O'Bradaigh, C.; Doyle, K.; Harrison, N.

2017-10-01

Out-of-Autoclave manufacturing methods, specifically Automated Tape Placement (ATP) and induction welding, used in the fabrication of a stiffened thermoplastic demonstrator panel, are presented in this study. The demonstrator panel consists of two stiffeners induction welded to a flat skin, to form a typical load bearing aerospace sub-component. The skin of the panel is manufactured from uni-directional Carbon Fibre (CF) Polyetheretherkeytone (PEEK) using laser assisted Automated Tape Placement (ATP) and the stiffeners are press formed from woven CF-PEEK. The stiffeners are fusion bonded to the skin using a continuous induction welding process. A susceptor material is used at the interface to ensure the required heating is concentrated at the weldline. Microscopy was used to examine the manufactured coupons for defects. Destructive testing was carried out to evaluate the strength of the overall assembly. The work shows that assemblies manufactured using continuous induction welding and ATP are suitable for load bearing aerospace applications.

Lightweight sidewalls for aircraft interior noise control

NASA Technical Reports Server (NTRS)

May, D. N.; Plotkin, K. J.; Selden, R. G.; Sharp, B. H.

1985-01-01

A theoretical and experimental study was performed to devise lightweight sidewalls for turboprop aircraft. Seven concepts for new sidewalls were analyzed and tested for noise reduction using flat panels of 1.2 m x 1.8 m (4 ft x 6 ft), some of which were aircraft-type constructions and some of which were simpler, easier-to-construct panels to test the functioning of an acoustic principle. Aircraft-application sidewalls were then conceived for each of the seven concepts, and were subjectively evaluated for their ability to meet aircraft nonacoustic design requirements. As a result of the above, the following sidewall concepts were recommended for further investigation: a sidewall in which the interior cavity is vented to ceiling and underfloor areas; sidewalls with wall-mounted resonators, one having a conventional trim panel and one a limp one; and a sidewall with a stiff outer wall and a limp trim panel. These sidewalls appear to promise lower weights than conventional sidewalls adjusted to meet similar acoustic requirements, and further development may prove them to be practical.

W-Band Transmission MeasurementS and X-Band Dielectric Properties Measurements for a Radome Material Sample

NASA Technical Reports Server (NTRS)

Cravey, Robin L.; Tiemsin, Pacita I.

1997-01-01

This paper describes measurements which were performed on a sample of radome material in the Electromagnetic Properties Measurements Laboratory (EPML). The purpose of the measurements described in this paper was to determine the one-way transmission loss through the flat panel of radome material for a frequency range of 84 to 94 GHz, for varying incidence angles. The panel, which was manufactured by Norton Performance Plastics Corporation, was provided to the EPML by TRW. The size of the panel is 40 in x 36 in x 0.422 in and consists of a foam material with one side coated with a smooth white coating (this side will be referred to as the front side). The dielectric properties of the foam material from the inside of the panel were also determined at X-band (8.2-12.4 GHz). The W-band free space measurements are presented first, followed by the X-band dielectric properties measurements.

Symmetric waterbomb origami.

PubMed

Chen, Yan; Feng, Huijuan; Ma, Jiayao; Peng, Rui; You, Zhong

2016-06-01

The traditional waterbomb origami, produced from a pattern consisting of a series of vertices where six creases meet, is one of the most widely used origami patterns. From a rigid origami viewpoint, it generally has multiple degrees of freedom, but when the pattern is folded symmetrically, the mobility reduces to one. This paper presents a thorough kinematic investigation on symmetric folding of the waterbomb pattern. It has been found that the pattern can have two folding paths under certain circumstance. Moreover, the pattern can be used to fold thick panels. Not only do the additional constraints imposed to fold the thick panels lead to single degree of freedom folding, but the folding process is also kinematically equivalent to the origami of zero-thickness sheets. The findings pave the way for the pattern being readily used to fold deployable structures ranging from flat roofs to large solar panels.

BUCLASP 2: A computer program for instability analysis of biaxially loaded composite stiffened panels and other structures

NASA Technical Reports Server (NTRS)

Tripp, L. L.; Tamekuni, M.; Viswanathan, A. V.

1973-01-01

The use of the computer program BUCLASP2 is described. The program is intended for linear instability analyses of structures such as unidirectionally stiffened panels. Any structure that has a constant cross section in one direction, that may be idealized as an assemblage of beam elements and laminated flat and curved plant strip elements can be analyzed. The loadings considered are combinations of axial compressive loads and in-plane transverse loads. The two parallel ends of the panel must be simply supported and arbitrary elastic boundary conditions may be imposed along any one or both external longitudinal side. This manual consists of instructions for use of the program with sample problems, including input and output information. The theoretical basis of BUCLASP2 and correlations of calculated results with known solutions, are presented.

40 CFR 52.1167 - EPA-approved Massachusetts State regulations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... coating, wood product surface coating, and flat wood paneling surface coating. 310 CMR 7.04(2) U Fossil... for smoke density instrument removal for certain facilities. 310 CMR 7.04(4)(a) U Fossil Fuel... facilities in that district can apply to burn fossil fuel with an ash content in excess of 9 pct bydry weight...

Getting Artsy with the Alphabet

ERIC Educational Resources Information Center

Gainer, Ruth Straus

2005-01-01

In this article, the author discusses the combined artistry of third, fourth, and fifth graders as they illuminate a formerly dark corner of their school's entry plaza with a sparkling mosaic mural. The students worked in small groups to form the letters of the alphabet on 12" x 15" (30.5 x 38 cm) panels of cement board decorated with flat-backed…

Investigation on the Acoustic Absorption of Flexible Micro-Perforated Panel with Ultra-Micro Perforations

NASA Astrophysics Data System (ADS)

Li, Guoxin; Tang, Xiaoning; Zhang, Xiaoxiao; Qian, Y. J.; Kong, Deyi

2017-11-01

Flexible micro-perforated panel has unique advantages in noise reduction due to its good flexibility compared with traditional rigid micro-perforated panel. In this paper, flexible micro-perforated panel was prepared by computer numerical control (CNC) milling machine. Three kinds of plastics including polyvinylchloride (PVC), polyethylene terephthalate (PET), and polyimide (PI) were taken as the matrix materials to prepare flexible micro-perforated panel. It has been found that flexible micro-perforated panel made of PET possessing good porosity and proper density, elastic modulus and poisson ratio exhibited the best acoustic absorption properties. The effects of various structural parameters including perforation diameter, perforation ratio, thickness and air gap have also been investigated, which would be helpful to the optimization of acoustic absorption properties.

Stokes parameters of phase-locked partially coherent flat-topped array laser beams propagating through turbulent atmosphere

NASA Astrophysics Data System (ADS)

Golmohammady, Sh; Ghafary, B.

2016-06-01

In this study, generalized Stokes parameters of a phase-locked partially coherent flat-topped array beam based on the extended Huygens-Fresnel principle and the unified theory of coherence and polarization have been reported. Analytical formulas for 2  ×  2 cross-spectral density matrix elements, and consequently Stokes parameters of a phase-locked partially coherent flat-topped array beam propagating through the turbulent atmosphere have been formulated. Effects of many physical attributes such as wavelength, turbulence strength, flatness order and other source parameters on the Stokes parameters, and therefore spectral degree of polarization upon propagation have been studied thoroughly. The behaviour of the spectral degree of coherence of a delineated beam for different source conditions has been investigated. It can be shown that four generalized Stokes parameters increase by raising the flatness order at the same propagation distance. Increasing the number of beams leads to a decrease in the Stokes parameters to zero slowly. The results are of utmost importance for optical communications.

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.

Finite-element nonlinear transient response computer programs PLATE 1 and CIVM-PLATE 1 for the analysis of panels subjected to impulse or impact loads

NASA Technical Reports Server (NTRS)

Spilker, R. L.; Witmer, E. A.; French, S. E.; Rodal, J. J. A.

1980-01-01

Two computer programs are described for predicting the transient large deflection elastic viscoplastic responses of thin single layer, initially flat unstiffened or integrally stiffened, Kirchhoff-Lov ductile metal panels. The PLATE 1 program pertains to structural responses produced by prescribed externally applied transient loading or prescribed initial velocity distributions. The collision imparted velocity method PLATE 1 program concerns structural responses produced by impact of an idealized nondeformable fragment. Finite elements are used to represent the structure in both programs. Strain hardening and strain rate effects of initially isotropic material are considered.

Hypervelocity Impact (HVI). Volume 2; WLE Small-Scale Fiberglass Panel Flat Multi-Layer Targets A-1, A-2, and B-1

NASA Technical Reports Server (NTRS)

Gorman, Michael R.; Ziola, Steven M.

2007-01-01

During 2003 and 2004, the Johnson Space Center's White Sands Testing Facility in Las Cruces, New Mexico conducted hypervelocity impact tests on the space shuttle wing leading edge. Hypervelocity impact tests were conducted to determine if Micro-Meteoroid/Orbital Debris impacts could be reliably detected and located using simple passive ultrasonic methods. The objective of Targets A-1, A-2, and B-2 was to study hypervelocity impacts through multi-layered panels simulating Whipple shields on spacecraft. Impact damage was detected using lightweight, low power instrumentation capable of being used in flight.

Hypervelocity Impact (HVI). Volume 4; WLE Small-Scale Fiberglass Panel Flat Target C-2

NASA Technical Reports Server (NTRS)

Gorman, Michael R.; Ziola, Steven M.

2007-01-01

During 2003 and 2004, the Johnson Space Center's White Sands Testing Facility in Las Cruces, New Mexico conducted hypervelocity impact tests on the space shuttle wing leading edge. Hypervelocity impact tests were conducted to determine if Micro-Meteoroid/Orbital Debris impacts could be reliably detected and located using simple passive ultrasonic methods. The objective of Target C-2 was to study impacts through the reinforced carboncarbon (RCC) panels of the Wing Leading Edge. Fiberglass was used in place of RCC in the initial tests. Impact damage was detected using lightweight, low power instrumentation capable of being used in flight.