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Sample records for led-based flasher system

  1. System Reliability for LED-Based Products

    SciTech Connect

    Davis, J Lynn; Mills, Karmann; Lamvik, Michael; Yaga, Robert; Shepherd, Sarah D; Bittle, James; Baldasaro, Nick; Solano, Eric; Bobashev, Georgiy; Johnson, Cortina; Evans, Amy

    2014-04-07

    Results from accelerated life tests (ALT) on mass-produced commercially available 6” downlights are reported along with results from commercial LEDs. The luminaires capture many of the design features found in modern luminaires. In general, a systems perspective is required to understand the reliability of these devices since LED failure is rare. In contrast, components such as drivers, lenses, and reflector are more likely to impact luminaire reliability than LEDs.

  2. Flasher Powered by Photovoltaic Cells and Ultracapacitors

    NASA Technical Reports Server (NTRS)

    Eichenberg, Dennis J.; Soltis, Richard F.

    2003-01-01

    A unique safety flasher powered by photovoltaic cells and ultracapacitors has been developed. Safety flashers are used wherever there are needs to mark actually or potentially hazardous locations. Examples of such locations include construction sites, highway work sites, and locations of hazardous operations. Heretofore, safety flashers have been powered by batteries, the use of which entails several disadvantages: Batteries must be kept adequately charged, and must not be allowed to become completely discharged. Batteries have rather short cycle lives, and their internal constituents that react chemically to generate electricity deteriorate (and hence power-generating capacities decrease) over time. The performances of batteries are very poor at low temperatures, which often occur in the circumstances in which safety flashers are most needed. The disposal of batteries poses a threat to the environment. The development of the present photovoltaic/ultracapacitor- powered safety flasher, in which the ultracapacitors are used to store energy, overcomes the aforementioned disadvantages of using batteries to store energy. The ultracapacitors in this flasher are electrochemical units that have extremely high volumetric capacitances because they contain large-surface-area electrodes separated by very small gaps. Ultracapacitors have extremely long cycle lives, as compared to batteries; consequently, it will never be necessary to replace the ultracapacitors in the safety flasher. The reliability of the flasher is correspondingly increased, and the life-of-system cost and the adverse environmental effects of the flasher are correspondingly reduced. Moreover, ultracapacitors have excellent low-temperature characteristics, are maintenance-free, and provide consistent performance over time.

  3. Physics with Flashers.

    ERIC Educational Resources Information Center

    Waugh, John; Chapman, Dan

    1983-01-01

    Describes construction of two flashing light sources: an adjustable-rate battery-powered flasher and a neon tube powered by a 60-hertz electrical outlet. Both devices may be used for a variety of activities, including studies of free-falling object, pendulum period variation, and acceleration due to gravity. (JN)

  4. Design of an LED-based compound optical system for a driving beam system.

    PubMed

    Ge, Aiming; Wang, Wei; Du, Zhengqing; Qiu, Peng; Wang, Junwei; Cai, Jinlin; Song, Xiaobo

    2013-04-20

    This paper proposes an LED-based compound optical system, which can be involved in the design of the driving beam system in automotive headlamps with high system efficiency and low power consumption. The compound system can meet the requirements announced in the UNECE regulation "Addendum 111: Regulation No. 112 Revision 2." Also, it is composed of a nonspherical reflector, a compound lens, and a two-dimensional diverging lens. Using a single device of high-brightness LED of merely 7.6 W, the specified illumination requirements for the driving beam can be achieved. As we have expected, on the test screen at a distance of 25 m, the simulation results, as well as the testing results for the prototype, can reach the illuminance distribution requirements, including all specified regions and key points. Moreover, this compound system enjoys the features of high compactness, high energy efficiency, and feasibility of manufacturing. PMID:23669678

  5. Implementation of an LED-based clinical spatial frequency domain imaging system

    NASA Astrophysics Data System (ADS)

    Mazhar, Amaan; Sharif, Seyed A.; Saggese, Steve; Choi, Bernard; Cuccia, David J.; Durkin, Anthony J.

    2012-03-01

    Spatial Frequency Domain Imaging (SFDI) is a non-contact imaging method that uses multiple frequency spatial illumination to generate two dimensional maps of tissue optical properties (absorption and reduced scattering) and chromophore concentrations. We present phantom validation and pilot clinical data of a deployed light-emitting diode (LED) based system. The system employs four LED wavelengths (658 nm, 730 nm, 850 nm, 970 nm) to quantitatively assess tissue health by measurement of common tissue constituents. Phantom validation results and maps of oxyhemoglobin, deoxy-hemoglobin, water content, reduced scattering, and surface topography will be presented for pilot studies assessing burn severity and efficacy of port wine stain treatment.

  6. Optical design and lighting application of an LED-based sports lighting system

    NASA Astrophysics Data System (ADS)

    Boxler, Larry

    2011-10-01

    This paper describes both the optical development of an LED-based sports lighting system and the results of the application of the system to an actual sport field. A traditional sport lighting fixture is generally composed of a single 1500 watt High Intensity Discharge (HID) light source with reflectors used to control the light distribution. The efficacy of the HID light source is equivalent or nearly equivalent to most LED light sources, putting LEDs at a large cost disadvantage in a high light output application such as sports lighting due to the number of LEDs and supporting components required to run an LED system. To assess the feasibility and applicability of LEDs in a sports lighting application, an LED-based sport light has been developed and installed on a small soccer field specified to have an average maintained illuminance level of 30 footcandles. An existing HID sport lighting system was also installed on the same size soccer field adjacent to the LED field with the same average footcandle level for comparison. Results indicate that LEDs can provide equivalent average illumination; however the LED source and system component cost is substantially higher. Despite the high cost, it was found that improved optical control afforded by the optical design used in the system provides a significant improvement in offsite wasted spill light, glare control, and on field uniformity. This could provide an advantage for LED systems.

  7. 21 CFR 886.1300 - Afterimage flasher.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Afterimage flasher. 886.1300 Section 886.1300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1300 Afterimage flasher. (a) Identification....

  8. Fast repetition rate (FRR) flasher

    DOEpatents

    Kolber, Zbigniew; Falkowski, Paul

    1997-02-11

    A fast repetition rate (FRR) flasher suitable for high flash photolysis including kinetic chemical and biological analysis. The flasher includes a power supply, a discharge capacitor operably connected to be charged by the power supply, and a flash lamp for producing a series of flashes in response to discharge of the discharge capacitor. A triggering circuit operably connected to the flash lamp initially ionizes the flash lamp. A current switch is operably connected between the flash lamp and the discharge capacitor. The current switch has at least one insulated gate bipolar transistor for switching current that is operable to initiate a controllable discharge of the discharge capacitor through the flash lamp. Control means connected to the current switch for controlling the rate of discharge of the discharge capacitor thereby to effectively keep the flash lamp in an ionized state between Successive discharges of the discharge capacitor. Advantageously, the control means is operable to discharge the discharge capacitor at a rate greater than 10,000 Hz and even up to a rate greater than about 250,000 Hz.

  9. Fast repetition rate (FRR) flasher

    DOEpatents

    Kolber, Z.; Falkowski, P.

    1997-02-11

    A fast repetition rate (FRR) flasher is described suitable for high flash photolysis including kinetic chemical and biological analysis. The flasher includes a power supply, a discharge capacitor operably connected to be charged by the power supply, and a flash lamp for producing a series of flashes in response to discharge of the discharge capacitor. A triggering circuit operably connected to the flash lamp initially ionizes the flash lamp. A current switch is operably connected between the flash lamp and the discharge capacitor. The current switch has at least one insulated gate bipolar transistor for switching current that is operable to initiate a controllable discharge of the discharge capacitor through the flash lamp. Control means connected to the current switch for controlling the rate of discharge of the discharge capacitor thereby to effectively keep the flash lamp in an ionized state between successive discharges of the discharge capacitor. Advantageously, the control means is operable to discharge the discharge capacitor at a rate greater than 10,000 Hz and even up to a rate greater than about 250,000 Hz. 14 figs.

  10. 21 CFR 886.1300 - Afterimage flasher.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL... afterimage flasher is an AC-powered light that automatically switches on and off to allow performance of an afterimage test in which the patient indicates the positions of afterimages after the light is off....

  11. 21 CFR 886.1300 - Afterimage flasher.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL... afterimage flasher is an AC-powered light that automatically switches on and off to allow performance of an afterimage test in which the patient indicates the positions of afterimages after the light is off....

  12. The Perseus Flasher and satellite glints

    NASA Technical Reports Server (NTRS)

    Schaefer, Bradley E.; Barber, Michael; Brooks, John J.; Deforrest, Allen; Malley, Paul D.

    1987-01-01

    The Perseus Flasher (PF) is claimed to be an astrophysical source which frequently emits bright optical flashes (Katz et al. 1986). These flashes have all been detected by the naked eye, with the exception of one photographed flash for which an accurate position is measured. Notable properties of the PF are its large amplitude (greater than 19 mag), short duration (about 1 s), and frequent occurrence (a flash every 12 hr). Here, evidence is presented that the PF is not an astrophysical source but is merely the observation of glints of reflected sunlight from artificial earth satellites. This conclusion is supported by the following facts: (1) a total of 3400 hr of photographic, video, and CCD observations have detected no flashes in or near the small PF error box, despite the claim of one bright flash every 12 hr; (2) thirteen of the 26 flashes are shown to be nonastrophysical in origin; and (3) both the observational and theoretical glint rates indicate that most, if not all, PF observations are caused by satellite glints.

  13. Non-contact tissue perfusion and oxygenation imaging using a LED based multispectral and a thermal imaging system, first results of clinical intervention studies

    NASA Astrophysics Data System (ADS)

    Klaessens, John H. G. M.; Nelisse, Martin; Verdaasdonk, Rudolf M.; Noordmans, Herke Jan

    2013-03-01

    During clinical interventions objective and quantitative information of the tissue perfusion, oxygenation or temperature can be useful for the surgical strategy. Local (point) measurements give limited information and affected areas can easily be missed, therefore imaging large areas is required. In this study a LED based multispectral imaging system (MSI, 17 different wavelengths 370nm-880nm) and a thermo camera were applied during clinical interventions: tissue flap transplantations (ENT), local anesthetic block and during open brain surgery (epileptic seizure). The images covered an area of 20x20 cm, when doing measurements in an (operating) room, they turned out to be more complicated than laboratory experiments due to light fluctuations, movement of the patient and limited angle of view. By constantly measuring the background light and the use of a white reference, light fluctuations and movement were corrected. Oxygenation concentration images could be calculated and combined with the thermal images. The effectively of local anesthesia of a hand could be predicted in an early stage using the thermal camera and the reperfusion of transplanted skin flap could be imaged. During brain surgery, a temporary hyper-perfused area was witnessed which was probably related to an epileptic attack. A LED based multispectral imaging system combined with thermal imaging provide complementary information on perfusion and oxygenation changes and are promising techniques for real-time diagnostics during clinical interventions.

  14. An LED-Based Gain Monitoring System for the PrimEx Hybrid Calorimeter at Jefferson Lab

    NASA Astrophysics Data System (ADS)

    Underwood, Jarreas

    2003-10-01

    The PrimEx Collaboration is preparing to perform a high precision ( ˜ 1.4%) measurement of the neutral pion decay width through two gamma decay mode. Knowledge of the pion decay width with such high accuracy will provide a stringent test of the fundamental symmetry breaking issue in QCD - the chiral anomaly. The theoretical prediction of the decay width is precise, and the 1.4% level measurement in PrimEx is adequate for this test. Pions will be produced in nuclear targets by the coherent photoproduction in the Coulomb field of a nucleus at small angles (Primakoff effect). The energy and coordinates of the resultant decay photons will be detected in a high resolution HYbrid CALorimeter (HYCAL) which consists of about 1200 lead tungstate crystal scintillators surrounded by ˜ 600 lead glass Cherenkov counters. HYCAL will be furnished with precise ˜ 0.1% gain monitoring system based on blue super-bright light emitting diodes. A 700-channel prototype system has been constructed for the prototype HYCAL-0 calorimeter. This system has been tested for both long-term stability and performance in the CEBAF photon beam. Additionally, fluctuations in the calorimeter high voltages were simulated during the beam test. The results of these tests will be presented. This project is being supported by NSF grants PHY-0079840 and PHY-0072466

  15. Using specific and adaptive arrangement of grid-type pilot in channel estimation for white-lightLED-based OFDM visible light communication system

    NASA Astrophysics Data System (ADS)

    Lin, Wan-Feng; Chow, Chi-Wai; Yeh, Chien-Hung

    2015-03-01

    Orthogonal frequency division multiplexing (OFDM) is a promising candidate for light emitting diode (LED)-based optical wireless communication (OWC); however, precise channel estimation is required for synchronization and equalization. In this work, we study and discover that the channel response of the white-lightLED-based OWC was smooth and stable. Hence we propose and demonstrate using a specific and adaptive arrangement of grid-type pilot scheme to estimate the LED OWC channel response. Experimental results show that our scheme can achieve better transmission performance and with some transmission capacity enhancement when compared with the method using training-symbol scheme (also called block-type pilot scheme).

  16. A Light Flasher and Its Use in the Elementary Mechanics Laboratory

    ERIC Educational Resources Information Center

    Wood, G. Theodore

    1974-01-01

    A light flasher was developed for use with the open-shutter photography technique in elementary-mechanics experiments. Details are given of its design and construction. Five experiments, for the elementary mechanics laboratory, which use flasher units are described. (DT)

  17. High-power white LED-based system incorporating a CCD Offner imaging spectrometer for real-time fluorescence qPCR measurements

    NASA Astrophysics Data System (ADS)

    Alaruri, Sami D.

    2014-12-01

    An optical system for qPCR fluorescence measurements which incorporates high-power white LEDs, PMMA plastic lenses and an Offner multichannel (imaging) CCD-based spectrometer has been developed and validated. The optical system can detect twenty reaction vessels in an asynchronous manner and up to seven different fluorescent dyes (7 plex) at 1 nM dye concentrations in each of the reaction vessels. Furthermore, PCR curves obtained using the optical measurement system for a genomic deoxyribonucleic acid (DNA) template containing HEX and Texas Red fluorescent probes (fluorophores) are discussed. The spectral resolution, dynamic range and repeatability of the measurement system are < 15 nm, > 3 decades and < 1% CV, respectively.

  18. A Simplified, Light Emitting Diode (LED) Based, Modular System to be Used for the Rapid Evaluation of Fruit and Vegetable Quality: Development and Validation on Dye Solutions

    PubMed Central

    Civelli, Raffaele; Giovenzana, Valentina; Beghi, Roberto; Naldi, Ezio; Guidetti, Riccardo; Oberti, Roberto

    2015-01-01

    NIR spectroscopy has proven to be one of the most efficient and ready to transfer tools to monitor product’s quality. Portable VIS/NIR instruments are particularly versatile and suitable for field use to monitor the ripening process or quality parameters. The aim of this work is to develop and evaluate a new simplified optoelectronic system for potential measurements on fruit and vegetables directly in the field. The development, characterization and validation of an operative prototype is discussed. LED technology was chosen for the design, and spectral acquisition at four specific wavelengths (630, 690, 750 and 850 nm) was proposed. Nevertheless, attention was given to the modularity and versatility of the system. Indeed, the possibility to change the light sources module with other wavelengths allows one to adapt the use of the same device for different foreseeable applications and objectives, e.g., ripeness evaluation, detection of particular diseases and disorders, chemical and physical property prediction, shelf life analysis, as well as for different natures of products (berry, leaf or liquid). Validation tests on blue dye water solutions have shown the capability of the system of discriminating low levels of reflectance, with a repeatability characterized by a standard deviation proportional to the measured intensity and in general limited to 2%–4%. PMID:26371002

  19. Testing of a simplified LED based vis/NIR system for rapid ripeness evaluation of white grape (Vitis vinifera L.) for Franciacorta wine.

    PubMed

    Giovenzana, Valentina; Civelli, Raffaele; Beghi, Roberto; Oberti, Roberto; Guidetti, Riccardo

    2015-11-01

    The aim of this work was to test a simplified optical prototype for a rapid estimation of the ripening parameters of white grape for Franciacorta wine directly in field. Spectral acquisition based on reflectance at four wavelengths (630, 690, 750 and 850 nm) was proposed. The integration of a simple processing algorithm in the microcontroller software would allow to visualize real time values of spectral reflectance. Non-destructive analyses were carried out on 95 grape bunches for a total of 475 berries. Samplings were performed weekly during the last ripening stages. Optical measurements were carried out both using the simplified system and a portable commercial vis/NIR spectrophotometer, as reference instrument for performance comparison. Chemometric analyses were performed in order to extract the maximum useful information from optical data. Principal component analysis (PCA) was performed for a preliminary evaluation of the data. Correlations between the optical data matrix and ripening parameters (total soluble solids content, SSC; titratable acidity, TA) were carried out using partial least square (PLS) regression for spectra and using multiple linear regression (MLR) for data from the simplified device. Classification analysis were also performed with the aim of discriminate ripe and unripe samples. PCA, MLR and classification analyses show the effectiveness of the simplified system in separating samples among different sampling dates and in discriminating ripe from unripe samples. Finally, simple equations for SSC and TA prediction were calculated. PMID:26452865

  20. Search for X-rays from the region of the Aries-Perseus flasher

    NASA Technical Reports Server (NTRS)

    Lewin, Walter H. G.; Van Paradijs, Jan; Damen, Eugene; Jansen, Fred; Mccall, Marshall L.

    1987-01-01

    The region containing the Perseus flasher was observed for 5.4 h with the Exosat observatory. Upper limits to a point source with a steady X-ray flux were 2 x 10 to the -12th erg/sq cm s and 6 x 10 to the 12th erg/sq cm s. Upper limits to X-ray flashes of about 1 s duration were 4 x 10 to the 9th erg/sq cm s and 7 x 10 to the -10th erg/sq cm s. In view of the growing number of negative optical observations, it appears that either the optical flashes do not have a celestial origin, or that the flasher has a transient character and turns off for extended periods of time.

  1. LED-based digital diameter measurement

    NASA Astrophysics Data System (ADS)

    Kleuver, Wolfram; Becker, Lothar

    1995-01-01

    This paper presents a new industrial sensor for measuring diameters of extreme thin objects. The system is divided in two parts. The first is the emitter and the second the receiver. It is possible to use this system for the automatic inspection of files and wires in the textile industries and wire works. Another application for the sensor is the control of production of chemical files in an extruder. Furthermore we can measure more than one object in the lightbeam because we get information not only about the dimensions also about the position of the objects in the beam. The innovation in this system is the using of a light emitting diode (LED) as emitter and the realization of a long distance of about two or more meters between the two sensorheads. The results of this development are a special kind of optical layout in the emitter to reduce the loss of intensity and minimize the divergence of the lightbeam. It is not necessary to develop an intensity distribution, which is equal over the complete width of the sensorhead. We can show that we have a better dynamic in the system with this feature. The experiments prove that we get the same resolution as a laserbeamsensor. Furthermore one advantage is the eye-safety.

  2. The Hottest Horizontal-Branch Stars in Omega Centauri: Late Hot Flasher vs. Helium Enrichment

    NASA Technical Reports Server (NTRS)

    Moehler, S.; Dreizler, S.; Lanz, T.; Bono, G.; Sweigart, A V.; Calamida, A.; Monelli, M.; Nonino, M.

    2007-01-01

    UV observations of some massive globular clusters uncovered a significant population of very hot stars below the hot end of the horizontal branch (HB), the so-called blue hook stars. This feature might be explained either by the late hot flasher scenario here stars experience the helium flash while on the white dwarf cooling curve or by the helium-rich sub-population recently postulated to exist in some clusters. Spectroscopic analyses of blue hook stars in omega Cen and NGC 2808 support the late hot flasher scenario, but the stars contain much less helium than expected and the predicted C, N enrichment could not be verified from existing data. We want to determine effective temperatures, surface gravities and abundances of He, C, N in blue hook and canonical extreme horizontal branch (EHB) star candidates. Moderately high resolution spectra of stars at the hot end of the blue horizontal branch in the globular cluster omega Cen were analysed for atmospheric parameters (T(sub eff), log g) and abundances using LTE and Non-LTE model atmospheres. In the temperature range 30,000 K to 50,000 K we find that 37% of our stars are helium-poor (log nHe/nH less than -2), 49% have solar helium abundance within a factor of 3 (-1.5 less than or equal to log nHe/nH less than or equal to -0.5) and 14% are helium rich (log nHe/nH greater than -0.4). We also find carbon enrichment in step with helium enrichment, with a maximum carbon enrichment of 3% by mass. At least 30% of the hottest HB stars in omega Centauri show helium abundances well above the predictions from the helium enrichment scenario (Y = 0.42 corresponding to log nHe/nH approximately equal to -0.74). In addition the most helium-rich stars show strong carbon enrichment as predicted by the late hot flasher scenario. We conclude that the helium-rich HB stars in omega Cen cannot be explained solely by the helium-enrichment scenario invoked to explain the blue main sequence.

  3. LED-based digital hologram reconstruction by compressive sensing

    NASA Astrophysics Data System (ADS)

    Weng, Jiawen; Yang, Chuping; Qin, Yi; Li, Hai

    2015-10-01

    LED-based digital hologram, considered as low-coherence digital hologram, is confined to in-line holography because the interference fringes could be observed only when the angle between the object and reference wave is small enough. So, phase-shifting technique is usually employed. But it is not fit for dynamic analysis for demanding more than one hologram. A numerical reconstruction method based on compressive sensing theory for single LED-based digital hologram is proposed to achieve dynamic analysis. By this method, the out-of-focus twin image and the coherent noise can be inhibited to some extent. The theory is presented in detail, and experimental result on LED-based digital holography with USAF pattern as test target, is performed to demonstrate the feasibility and validity of the method.

  4. Search for X-rays from the region of the Aries-Perseus flasher

    NASA Astrophysics Data System (ADS)

    Lewin, Walter H. G.; van Paradijs, Jan; Damen, Eugene; Jansen, Fred; McCall, Marshall L.; Feldman, P. A.; Tapping, K. F.

    1987-08-01

    The region containing the Perseus flasher (Katz et al., 1986) was observed for 5.4 hr with the EXOSAT observatory. Upper limits (2 σ levels of confidence) to a point source with a steady X-ray flux were 2×10-12erg cm-2s-1 (0.1 - 2 keV) and 6×10-12erg cm-2s-1 (1 - 20 keV). Upper limits (4 σ level of confidence) to X-ray flashes of ≡1 s duration were 4×10-9erg cm-2s-1 (0.1 - 2 keV) and 7×10-10erg cm-2s-1 (1 - 20 keV).

  5. Hybrid power management system and method

    NASA Technical Reports Server (NTRS)

    Eichenberg, Dennis J. (Inventor)

    2007-01-01

    A system and method for hybrid power management. The system includes photovoltaic cells, ultracapacitors, and pulse generators. In one embodiment, the hybrid power management system is used to provide power for a highway safety flasher.

  6. Hybrid Power Management System and Method

    NASA Technical Reports Server (NTRS)

    Eichenberg, Dennis J. (Inventor)

    2008-01-01

    A system and method for hybrid power management. The system includes photovoltaic cells, ultracapacitors, and pulse generators. In one embodiment, the hybrid power management system is used to provide power for a highway safety flasher.

  7. Testing the hot-flasher scenario with asteroseismological tools. First Results

    NASA Astrophysics Data System (ADS)

    Miller Bertolami, M. M.; Córsico, A. H.; Althaus, L. G.

    2010-11-01

    A core helium flash after the departure from the red giant branch (i.e. "hot-flasher scenario") offers one of the most promising explanations for the origin of He-sdO stars. Recently, Miller Bertolami et al. (2008) have shown that many surface properties of H-deficient sdO stars (the He-sdO stars) could be explained through this scenario if chemical diffusion is taken into account. In this context the He-sdO stars formed during a hot-flasher event would transform into H-rich hot-sdB stars (33000-38000 K) as a consequence of diffusion of the remaining H towards the surface of the star. Thus, some hot sdBs might be the descendants of He-sdO stars that have previously burnt most of their H-content and, thus, a very thin H envelope should be expected (10-9 to 10-10 M⊙, see Miller Bertolami et al. 2008 for details). Interestingly enough, the location of these sdB stars in the logg - Teff diagram should overlap with the domain of the rapidly pulsating (p-mode) EC 14026 stars. This fact opens the interesting possibility of employing asteroseismology to investigate the existence of hot-sdB stars characterized by such very thin H envelopes. In this preliminary investigation, we explore the sensitivity of the acoustic pulsation spectrum of EC 14026 stars to the thickness of the H envelope. The pulsation analysis presented in this work was performed with the help of the adiabatic radial and nonradial pulsation code employed by our group in numerous asteroseismological studies of white dwarfs and pre-white dwarfs (see Córsico et al. 2008 and references therein). The stellar models adopted in the present study where extracted from the 0.48150 M⊙ (Z= 0.001) sequence of Miller Bertolami et al. (2008). Given the exploratory nature of this work, in order to analyze the effects of different thicknesses of the H-rich envelope on the pulsation spectrum of sdB stars we have artificially added a H-rich envelope in the outermost layers of our initial model. We have considered four

  8. LED-based near infrared sensor for cancer diagnostics

    NASA Astrophysics Data System (ADS)

    Bogomolov, Andrey; Ageev, Vladimir; Zabarylo, Urszula; Usenov, Iskander; Schulte, Franziska; Kirsanov, Dmitry; Belikova, Valeria; Minet, Olaf; Feliksberger, E.; Meshkovsky, I.; Artyushenko, Viacheslav

    2016-03-01

    Optical spectroscopic technologies are increasingly used for cancer diagnostics. Feasibility of differentiation between malignant and healthy samples of human kidney using Fluorescence, Raman, MIR and NIR spectroscopy has been recently reported . In the present work, a simplification of NIR spectroscopy method has been studied. Traditional high-resolution NIR spectrometry was replaced by an optical sensor based on a set of light-emitting diodes at selected wavelengths as light sources and a photodiode. Two prototypes of the sensor have been developed and tested using 14 in-vitro samples of seven kidney tumor patients. Statistical evaluation of results using principal component analysis and partial least-squares discriminant analysis has been performed. Despite only partial discrimination between tumor and healthy tissue achieved by the presented new technique, the results evidence benefits of LED-based near-infrared sensing used for oncological diagnostics. Publisher's Note: This paper, originally published on 4 March, 2016, was replaced with a corrected/revised version on 7 April, 2016. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance.

  9. Compact LED based LCOS optical engine for mobile projection

    NASA Astrophysics Data System (ADS)

    Zhang, Wenzi; Li, Xiaoyan; Liu, Qinxiao; Yu, Feihong

    2009-11-01

    With the development of high power LED (light emitting diode) technology and color filter LCOS (liquid crystal on silicon) technology, the research on LED based micro optical engine for mobile projection has been a hot topic recently. In this paper one compact LED powered LCOS optical engine design is presented, which is intended to be embedded in cell phone, digital camera, and so on. Compared to DLP (digital light processor) and traditional color sequential LCOS technology, the color filter based LCOS panel is chosen for the compact optical engine, this is because only white LED is needed. To further decrease the size of the optical engine, only one specifically designed plastic free form lens is applied in the illumination part of the optical engine. This free form lens is designed so that it plays the roles of both condenser and integrator, by which the output light of LED is condensed and redistributed, and light illumination of high efficiency, high uniformity and small incident angle on LCOS is acquired. Besides PBS (polarization beam splitter), LCOS, and projection lens, the compact optical engine contains only this piece of free form plastic lens, which can be produced by plastic injection molding. Finally a white LED powered LCOS optical engine with a compact size of less than 6.6 cc can be acquired. With the ray tracing simulation result, the light efficiency analysis shows that the output flux is over 8.5 ANSI lumens and the ANSI uniformity of over 80%.

  10. Economical LED based, real-time, in vivo imaging of murine corneal wound healing.

    PubMed

    Ghoghawala, S Y; Mannis, M J; Murphy, C J; Rosenblatt, M I; Isseroff, R R

    2007-06-01

    An optimal system for monitoring in vivo corneal wound healing is inexpensive, has utility for wounding and imaging, and is able to provide previews before photography. We outline such an imaging system that takes advantage of a consumer digital camera and an LED-based light source for fluorescein excitation. Using FVB/NJ mice, 2mm diameter, circular, axial corneal epithelial defects were created using a crescent blade. The corneal wounds were imaged every four hours until healed using a Nikon Coolpix 5400 camera attached to a Nikon SMZ-10A stereomicroscope, using the illumination from a 16 LED 464nm flashlight. The wound area was calculated, and the linear regressions of the linear phase of wound healing were compared using the F-test. The slopes of the linear regressions for the 6 trials of 4 mice/trial had an average of -52.95microm/h (SEM=0.55microm/h) and were statistically equivalent (p>0.05). The mean of the R(2) values for the linear regressions was 0.9546 (SEM=0.0121). The equivalent linear regressions and R(2)>0.90 suggest that the imaging system could precisely monitor the wound healing of multiple trials and of animals within each trial, respectively. Using a consumer digital camera and LED-based illumination, we have established a system that is economical, is used in both wounding and imaging, is operated by a single person, and is able to provide real-time previews to monitor corneal wound healing precisely. PMID:17445800

  11. Design of LED-based reflector-array module for specific illuminance distribution

    NASA Astrophysics Data System (ADS)

    Chen, Enguo; Yu, Feihong

    2013-02-01

    This paper presents an efficient and practical design method for a LED based reflector-array lighting module. Improving on previous designs, this method could offer higher design freedom to achieve specific illuminance distribution for actual lighting application and deal with the LED light intensity distribution while shortening the design time. The detailed design description of the lighting system is thoroughly investigated. To demonstrate the effectiveness of this method, an ultra-compact reflector-array module, which produces a rectangular illumination area with a large aspect ratio, is specially designed to meet the high-demanding requirements of industrial lighting application. Design results show that most LED emitting energy could be collected into the required lighting region while higher-brightness and better-uniformity are simultaneously available within the focus region. It is expected that this method will have great potential for other lighting applications.

  12. LED-based endoscopic light source for spectral imaging

    NASA Astrophysics Data System (ADS)

    Browning, Craig M.; Mayes, Samuel; Favreau, Peter; Rich, Thomas C.; Leavesley, Silas J.

    2016-03-01

    Colorectal cancer is the United States 3rd leading cancer in death rates.1 The current screening for colorectal cancer is an endoscopic procedure using white light endoscopy (WLE). There are multiple new methods testing to replace WLE, for example narrow band imaging and autofluorescence imaging.2 However, these methods do not meet the need for a higher specificity or sensitivity. The goal for this project is to modify the presently used endoscope light source to house 16 narrow wavelength LEDs for spectral imaging in real time while increasing sensitivity and specificity. The process to do such was to take an Olympus CLK-4 light source, replace the light and electronics with 16 LEDs and new circuitry. This allows control of the power and intensity of the LEDs. This required a larger enclosure to house a bracket system for the solid light guide (lightpipe), three new circuit boards, a power source and National Instruments hardware/software for computer control. The results were a successfully designed retrofit with all the new features. The LED testing resulted in the ability to control each wavelength's intensity. The measured intensity over the voltage range will provide the information needed to couple the camera for imaging. Overall the project was successful; the modifications to the light source added the controllable LEDs. This brings the research one step closer to the main goal of spectral imaging for early detection of colorectal cancer. Future goals will be to connect the camera and test the imaging process.

  13. Optical design of LED-based automotive tail lamps

    NASA Astrophysics Data System (ADS)

    Domhardt, André; Rohlfing, Udo; Klinger, Karsten; Manz, Karl; Kooß, Dieter; Lemmer, Uli

    2007-09-01

    The application of ultra bright monochromatic and white High-Power-LEDs in the range of automotive lighting systems is now state of the art. These LEDs offer new possibilities in optical design and engineering within different fields of automotive lighting, e.g., tail lamps, signal lamps, headlamps and interior lighting. This contribution describes the process of the optical design of an automotive LED tail lamp based on a practical example. We will elaborate the principal geometric approach, the radiometric conditions and the optical design by using standard and advanced mathematical optimization methods. Special attention will be paid to the following topics: efficient light coupling from the LED into the optical device, adaptation of the illuminance and optimization with respect to the requirements from SAE/ECE regulations. It will be shown that the development of LED-lamps requires the complex interaction of several factors. The challenge for the optical designer is to fulfill the technical demands while also considering the appearance of the final product desired by the customer. Further design specifications emerge from the electrical and thermal layout of the lamp.

  14. Investigation of the spectral properties of LED-based MR16s for general illumination

    NASA Astrophysics Data System (ADS)

    Brown, David F.; Nicol, David B.; Payne, Adam; Ferguson, Ian T.

    2004-10-01

    The spectral properties of commercially available LED-based and halogen MR16s were investigated. The measurements taken include TLF (Total Luminous Flux), CCT (Correlated Color Temperature), CRI (Color Rendering Index), angular variation of CCT, and luminous efficacy. The halogen MR16s were used as a baseline for comparison with LED-based MR16s. It is shown at this time that LED-based MR16s are not suitable as a direct replacement for existing alternatives due to high initial cost, low power efficiency, poor CRIs, and undesirable CCTs.

  15. Spectroscopic Analyses of the "Blue Hook" Stars in Omega Centauri: A Test of the Late Hot Flasher Scenario

    NASA Technical Reports Server (NTRS)

    Moehler, S.; Sweigart, Allan V.; Landsman, W. B.; Dreizler, S.; Rabin, Douglas M. (Technical Monitor)

    2002-01-01

    (Omega) Cen contains the largest population of very hot horizontal branch (HB) stars known in a globular cluster. Recent UV observations (Whitney et al. 1998; D'Cruz et al. 2000) show a significant population of hot stars below the zero-age horizontal branch ("blue hook" stars), which cannot be explained by canonical stellar evolution. Stars which suffer unusually large mass loss on the red giant branch and thus experience the helium core flash while descending the white dwarf cooling curve could populate this region. Theory predicts that these "late hot flashers" should show higher temperatures than the hottest canonical HB stars and should have helium- and carbon-rich atmospheres. We obtained and analysed medium resolution spectra of a sample of blue hook stars to derive their atmospheric parameters. The blue hook stars are indeed both hotter (T(sub eff)>35,000 K) and more helium-rich than classical extreme HB stars. In addition we find indications for a large enhancement of the carbon abundance relative to the cluster abundance.

  16. LED-based UV absorption detector with low detection limits for capillary liquid chromatography.

    PubMed

    Sharma, Sonika; Tolley, H Dennis; Farnsworth, Paul B; Lee, Milton L

    2015-01-20

    A 260 nm deep UV LED-based absorption detector with low detection limits was developed and integrated with a small nanoflow pumping system. The detector is small in size (5.2 × 3.0 cm) and weighs only 85 g (without electronics). This detector was specifically designed and optimized for on-column detection to minimize extra-column band broadening. No optical reference was included due to the low drift in the signal. Two ball lenses, one of which was integrated with the LED, were used to increase light throughput through the capillary column. Stray light was minimized by the use of a band-pass filter and an adjustable slit. Signals down to the parts per billion level (nanomolar) were easily detected with a short-term noise level of 4.4 μAU, confirming a low limit of detection and low noise. The detection limit for adenosine-5'-monophosphate was 230 times lower than any previously reported values. Good linearities (3 orders of magnitude) were obtained using sodium anthraquinone-2-sulfonate, adenosine-5'-monophosphate, dl-tryptophan, and phenol. The LC system was demonstrated by performing isocratic separation of phenolic compounds using a monolithic capillary column (16.5 cm × 150 μm i.d.) synthesized from poly(ethylene glycol) diacrylate. PMID:25496031

  17. Non-linearity measurements of solar cells with an LED-based combinatorial flux addition method

    NASA Astrophysics Data System (ADS)

    Hamadani, Behrang H.; Shore, Andrew; Roller, John; Yoon, Howard W.; Campanelli, Mark

    2016-02-01

    We present a light emitting diode (LED)-based system utilizing a combinatorial flux addition method to investigate the non-linear relationship in solar cells between the output current of the cell and the incident irradiance level. The magnitude of the light flux is controlled by the supplied currents to two LEDs (or two sets of them) in a combinatorial fashion. The signals measured from the cell are arranged within a related overdetermined linear system of equations derived from an appropriately chosen Nth degree polynomial representing the relationship between the measured signals and the incident fluxes. The flux values and the polynomial coefficients are then solved for by linear least squares to obtain the best fit. The technique can be applied to any solar cell, under either monochromatic or broadband spectrum. For the unscaled solution, no reference detectors or prior calibrations of the light flux are required. However, if at least one calibrated irradiance value is known, then the entire curve can be scaled to an appropriate spectral responsivity value. Using this technique, a large number of data points can be obtained in a relatively short time scale over a large signal range.

  18. Investigation of the spectral properties of LED-based MR16 bulbs for general illumination

    NASA Astrophysics Data System (ADS)

    Brown, David F.; Nicol, David B.; Ferguson, Ian T.

    2005-11-01

    The spectral properties of commercially available halogen and LED-based MR16s were investigated. The metrics used to characterize the MR16s include the total luminous flux (TLF), correlated color temperature (CCT), color-rendering index (CRI), angular variation of CCT, and luminous efficacy. The halogen MR16s were included as a baseline for comparison with LED-based MR16s. Seven LED-based MR16s were investigated, including three constructed from 5-mm LEDs, and four constructed from high-power devices based on a larger die. It is shown that MR16s constructed from white LEDs are not suitable as a direct replacement for existing alternatives at this time, due to their low power efficiency and poor TLF. MR16s constructed with a single phosphor also have poor CRIs and undesirable CCTs. An MR16 with an extra phosphor in the red region of the spectrum shows improvement in CRI and a lower CCT than the other LED-based MR16s. All of the LED-based MR16s had a variation of CCT that was larger than those of the halogen devices.

  19. Optical design of a high-power LED-based solar simulator

    NASA Astrophysics Data System (ADS)

    Toro-Betancur, Veronica; Velásquez-López, Alejandro; Velásquez, David; Acevedo-Gómez, David

    2016-04-01

    The optical design of a High-Power LED based Solar Simulator was made in order to reach the AM1.5G spectrum standards. An optical model of the light emitted by the LEDs was made and used for spectral intensities calculations and the light intensity uniformity was optimized. A class AAA solar simulator was designed using a hexagonal LED distribution.

  20. High-output LED-based light engine for profile lighting fixtures with high color uniformity using freeform reflectors.

    PubMed

    Gadegaard, Jesper; Jensen, Thøger Kari; Jørgensen, Dennis Thykjær; Kristensen, Peter Kjær; Søndergaard, Thomas; Pedersen, Thomas Garm; Pedersen, Kjeld

    2016-02-20

    In the stage lighting and entertainment market, light engines (LEs) for lighting fixtures are often based on high-intensity discharge (HID) bulbs. Switching to LED-based light engines gives possibilities for fast switching, additive color mixing, a longer lifetime, and potentially, more energy-efficient systems. The lumen output of a single LED is still not sufficient to replace an HID source in high-output profile fixtures, but combining multiple LEDs can create an LE with a similar output, but with added complexity. This paper presents the results of modeling and testing such a light engine. Custom ray-tracing software was used to design a high-output red, green and blue LED-based light engine with twelve CBT-90 LEDs using a dual-reflector principle. The simulated optical system efficiency was 0.626 with a perfect (R=1) reflector coating for light delivered on a target surface through the entire optical system. A profile lighting fixture prototype was created, and provided an output of 6744 lumen and an efficiency of 0.412. The lower efficiency was mainly due to a non-optimal reflector coating, and the optimized design is expected to reach a significantly higher efficiency. PMID:26906589

  1. Cosmic Flasher Reveals All!

    NASA Astrophysics Data System (ADS)

    1998-09-01

    For more information on magnetars and soft gamma-ray repeaters, see the Background Information which includes a "movie" of the flashing magnetar nebula, as seen by the VLA. Astronomers have found evidence for the most powerful magnetic field ever seen in the universe. They found it by observing a long-sought, short-lived "afterglow" of subatomic particles ejected from a magnetar -- a neutron star with a magnetic field billions of times stronger than any on Earth and 100 times stronger than any other previously known in the Universe. The afterglow is believed to be the aftermath of a massive starquake on the neutron star's surface. "And where there's smoke, there's fire, and we've seen the 'smoke' that tells us there's a magnetar out there," says Dale Frail, who used the National Science Foundation's Very Large Array (VLA) radio telescope to make the discovery. "Nature has created a unique laboratory where there are magnetic fields far stronger than anything that can be created here on Earth. As a result, the study of these objects enables us to study the effects of extraordinarily intense magnetic fields on matter," explains Dr. Morris L. Aizenman, Executive Officer in the Division of Astronomy at the National Science Foundation. Frail, an astronomer at the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico, along with Shri Kulkarni and Josh Bloom, astronomers at Caltech, discovered radio emission coming from a strange object 15,000 light-years away in our own Milky Way Galaxy. The radio emission was seen after the object experienced an outburst of gamma-rays and X-rays in late August. "This emission comes from particles ejected at nearly the speed of light from the surface of the neutron star interacting with the extremely powerful magnetic field," said Kulkarni. This is the first time this phenomenon, predicted by theorists, has been seen so clearly from a suspected magnetar. "Magnetars are expected to behave in certain ways. Astronomers have seen one type of their predicted activity previously, and now we've seen a completely different piece of evidence that says this is, in fact, a magnetar. That's exciting." Kulkarni said. The new discovery, the scientists say, will allow them to decipher further details about magnetars and their outbursts. SGR 1900+14 VLA Images of SGR 1900+14, with its short-lived radio emission turned off, left, and on, right. The radio emission comes from the interaction of subatomic particles with the magnetar's powerful magnetic field. The circles indicate the area from within which the X-ray emission of SGR 1900+14 comes. Magnetars were proposed in 1992 as a theoretical explanation for objects that repeatedly emit bursts of gamma-rays. These objects, called "soft gamma-ray repeaters," or SGRs, were identified in 1986. There still are only four of these known. They are believed to be rotating, superdense neutron stars, like pulsars, but with much stronger magnetic fields. Neutron stars are the remains of massive stars that explode as a supernova at the end of their normal lifetime. They are so dense that a thimbleful of neutron-star material would weigh 100 million tons. An ordinary pulsar emits "lighthouse beams" of radio waves that rotate with the star. When the star is oriented so that these beams sweep across the Earth, radio telescopes detect regularly-timed pulses. A magnetar is a neutron star with an extremely strong magnetic field, strong enough to rip atoms apart. In the units used by physicists, the strength of a magnetar's magnetic field is about a million billion Gauss; a refrigerator magnet has a field of about 100 Gauss. This superstrong magnetic field produces effects that distinguish magnetars from other neutron stars. First, the magnetic field is thought to act as a brake, slowing the star's rotation. The earlier discovery of pulsations several seconds apart in three SGRs indicated rotation rates slowed just as predicted by magnetar theory. Next, the magnetic field is predicted to cause "starquakes" in which the solid crust of the neutron star is cracked, releasing energy. That energy is released in two forms -- a burst of gamma-rays and X-rays and an ejection of subatomic particles at nearly the speed of light. The gamma-ray and X-ray burst lasts no more than a few minutes, while the ejected particles, interacting with the star's magnetic field, can produce detectable amounts of radio emission for several days. On August 27, the SGR called 1900+14 underwent a tremendous burst, the likes of which had not been seen since 1979. "For a number of years now, I've been routinely looking toward the region of sky where we thought this thing might be," said Frail, "hoping the magnetar would show itself." It did not disappoint; on September 3, the VLA found a new source of radio emission where one had not previously existed. The source quickly faded from view one week later. The immediate importance of this finding is that it provides a new and independent confirmation of the magnetar model. These impulsive particle "winds," predicted by theory, carry as much energy as the flashes of hard X-ray emission and are important in slowing down the spinning magnetar. This discovery also allows astronomers to pinpoint the exact location of the SGR to allow further study of the magnetar with other powerful telescopes. "Trying to find this source of gamma-rays was like nighttime sailing with a broken lighthouse; now, we're no longer in the dark, and can study the magnetar for years to come," said Bloom. In time, the free-flowing particle wind can inflate a nebula called a plerion. "This 'windbag nebula' can tell us a lot about the outflow of particles and the burst history of the object," Frail said. "In fact, studying this phenomenon can give us information about the magnetar that we can't learn any other way." The VLA is an instrument of the National Radio Astronomy Observatory, a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

  2. Influences of colorful LED emissions on spectrophotometric properties of a LED based white light source

    NASA Astrophysics Data System (ADS)

    Sametoglu, F.; Celikel, O.

    2011-05-01

    A LED based white light source (WLS) is designed and constructed to determine the color characteristics of the samples having specular and diffuse reflectance properties at the standard measurement conditions of 0/45 and d/8. The light source is composed of high power cool white and ultraviolet light emitting diodes (LEDs) which are operable in adjustable current levels. In order to combine the light beams emerging from two LED sources, a 1x2 fiber optic combiner is used. Optical characterizations of the light source designed and influences of several colorful LEDs called Royal-Blue, Blue, Cyan, Green, Amber, Red-Orange and Red on spectrophotometric properties of the light source are investigated.

  3. Colour shift and mechanism investigation on the PMMA diffuser used in LED-based luminaires

    NASA Astrophysics Data System (ADS)

    Lu, Guangjun; van Driel, W. D.; Fan, Xuejun; Yazdan Mehr, M.; Fan, Jiajie; Qian, Cheng; Jansen, K. M. B.; Zhang, G. Q.

    2016-04-01

    PMMA material is widely used in LED-based luminaires due to several advantages such as excellent optical transparency, durability against radiation, surface hardness (scratch free), rigidity and strength and can be completely recycled. However, few studies have been reported on the colour shift and failure mechanisms caused by this type of material. This paper experimentally investigated PMMA materials with different aging conditions. The following conclusions could be drawn. (1) Discolouration was not observed for any sample subjected to aging of 85 °C for 5000 h, or with additional blue light irradiation for 5000 h, or with additional humidity of 85%RH for 5000 h, or even with aging of 100 °C for 3000 h. (2) The specimen subjected to aging of 150 °C for 360 h has a surface discoloration and has a significant wavelength dependent degradation in the transmission spectrum caused by oxidation. The specimen with aging of 100 °C for 3000 h has a less oxidation, although no significant transmission spectrum reduction was observed. (3) Using such aged specimen as a diffuser mounted on a LED-based luminaire, the radiant flux peak intensity in the blue light area has a more severe reduction than that in the yellow light area, which results in a reduction of the radiant flux intensity ratio of blue light to yellow light and hence induces the colour shift to yellow. The colour shift investigated is 0.005, very close to the general failure criterion of 0.007, while the lumen decay is 10.2%, far less than the failure criterion of 30%.

  4. Angularly positioned LED-based spatial-temporal color separation system.

    PubMed

    Lee, Chi-Hung

    2012-08-13

    This study proposes a two-field driving scheme for field sequential color liquid crystal displays (LCDs) without color filters. The proposed scheme is based on angularly positioned color LEDs. In each field, the angular rays of two colors are collimated by a collimation lens, redirected by a light guide, and converged by a cylindrical-lens array to map into corresponding sub-pixel positions to efficiently display color images. The three main advantages of this approach are the elimination of dye color filters, high feasibility using conventional ultra-precision machining processes, and a larger color gamut. PMID:23038551

  5. NO2 measurements in Hong Kong using LED based long path differential optical absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Chan, K. L.; Pöhler, D.; Kuhlmann, G.; Hartl, A.; Platt, U.; Wenig, M. O.

    2012-05-01

    In this study we present the first long term measurements of atmospheric nitrogen dioxide (NO2) using a LED based Long Path Differential Optical Absorption Spectroscopy (LP-DOAS) instrument. This instrument is measuring continuously in Hong Kong since December 2009, first in a setup with a 550 m absorption path and then with a 3820 m path at about 30 m to 50 m above street level. The instrument is using a high power blue light LED with peak intensity at 450 nm coupled into the telescope using a Y-fibre bundle. The LP-DOAS instrument measures NO2 levels in the Kowloon Tong and Mongkok district of Hong Kong and we compare the measurement results to mixing ratios reported by monitoring stations operated by the Hong Kong Environmental Protection Department in that area. Hourly averages of coinciding measurements are in reasonable agreement (R = 0.74). Furthermore, we used the long-term data set to validate the Ozone Monitoring Instrument (OMI) NO2 data product. Monthly averaged LP-DOAS and OMI measurements correlate well (R = 0.84) when comparing the data for the OMI overpass time. We analyzed weekly patterns in both data sets and found that the LP-DOAS detects a clear weekly cycle with a reduction on weekends during rush hour peaks, whereas OMI is not able to observe this weekly cycle due to its fix overpass time (13:30-14:30 LT - local time).

  6. Degradation of Microcellular PET reflective materials used in LED-based products

    NASA Astrophysics Data System (ADS)

    Lu, Guangjun; van Driel, W. D.; Fan, Xuejun; Yazdan Mehr, M.; Fan, Jiajie; Jansen, K. M. B.; Zhang, G. Q.

    2015-11-01

    Microcellular PET is an emerging reflective material used for solid state lighting. This paper experimentally investigated its degradation mechanisms and quantified both lumen decay and color shift effects of LED-based products with this material aged under different conditions. The results show that: (1) A humidity test at 85 °C & 85%RH for 4000 h (or even shorter) can lead to hydrolytic degradation, which causes both the obvious inconsistent decrease of reflectivity and a severe embrittlement; (2) Oxidative degradation occurred at 85 °C for 4000 h can cause a slight reflectance spectrum change, while the additional blue light exposure has little impact; (3) Color shift induced by thermal aging at 85 °C for 4000 h is 0.0001 and lumen efficiency decreased by 1.57%. When Microcellular PET falls off due to the embrittlement during humidity test, the color shift increases to 0.0004 and the lumen efficiency is reduced by 4.47%.

  7. Development of LEDs-based microplate reader for bioanalytical assay measurements

    NASA Astrophysics Data System (ADS)

    Alaruri, Sami D.; Katzlinger, Michael; Schinwald, Bernhard; Kronberger, Georg; Atzler, Joseph

    2013-10-01

    The optical design for an LEDs-based microplate reader that can perform fluorescence intensity (top and bottom), absorbance, luminescence and time-resolved fluorescence measurements is described. The microplate reader is the first microplate reader in the marketplace that incorporates LEDs as excitation light sources. Absorbance measurements over the 0-3.5 optical density range for caffeine solution are presented. Additionally, fluorescence intensity readings collected at 535 and 625 nm from a green and a red RediPlateTM are reported. Furthermore, fluorescence decay lifetime measurements obtained for Eu (europium) and Sm (samarium) standard solutions using 370 nm excitation are presented. The microplate reader detection limits for the fluorescence intensity top, fluorescence intensity bottom, fluorescence polarization and time-resolved fluorescence modes are 1.5 fmol 100 µL-1 fluorescein (384-well plate), 25 fmol 100 µL-1 fluorescein (384-well plate), 5 mP at 10 nM fluorescein (black 384-well plate) and 30 amol 100 µL-1 europium solution (white 384-well plate), respectively.

  8. Accelerated life test for high-power white LED based on spectroradiometric measurement

    NASA Astrophysics Data System (ADS)

    Shen, Haiping; Pan, Jiangen; Feng, Huajun

    2008-03-01

    We implement an accelerated life test for the high-power white LEDs based on spectroradiometric measurement. The luminous flux degradation performances are investigated at both the rated current of 350mA and a higher current of 500mA. The average lifetime of the LEDs is 7057 hours at 350mA and 3508 hours at 500mA. The variations of the color of the white LEDs are studied. The color of the low quality white LEDs changes greatly, while the high quality white LEDs keep their color stable. The degradation performances of the chip and phosphor are studied separately. The quantum efficiency of the phosphor becomes lower from 350mA to 500mA current supply. The LED chip degrades faster than the phosphor during the 500mA high current aging. The luminous flux increase and the peak wavelength shift from 350mA to 500mA current supply are found to be useful lifetime indicating parameters that correlate well to the reliability of the high-power white LEDs.

  9. Advances toward commercialization of a new generation of low cost (O)LED-based dissolved oxygen and bioanalyte monitors

    NASA Astrophysics Data System (ADS)

    Smith, Alex; Cai, Yuankun; Vengasandra, Srikanth; Shinar, Ruth; Shinar, Joseph

    2010-08-01

    Recent advances toward commercialization of a new generation of low-cost LED- and OLED-based monitors for dissolved oxygen (DO), and multiple (bio)analytes such as glucose, lactate, alcohol, and cholesterol are described. The design of the DO monitors, which contain no optical fibers, filters, mirrors, or lens, is significantly simpler and consequently lower-cost than that of commercial LED-based DO monitors. The multiple (bio)analyte monitors are based on a DO monitor and the oxidase enzyme specific to each analyte. The potential advantages and disadvantages of the OLED- vs LED-based monitors is also discussed.

  10. Real-time water and wastewater quality monitoring using LED-based fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Bridgeman, John; Zakharova, Yulia

    2016-04-01

    In recent years there have been a number of attempts to design and introduce into water management tools that are capable of measuring organic and microbial matter in real time and in situ. This is important, as the delivery of safe water to customers, and the discharge of good quality effluent to rivers are primary concerns to water undertakers. A novel, LED-based portable fluorimeter 'Duo Fluor' has been designed and constructed at the University of Birmingham to monitor the quality of (waste)water continuously and in real time, and its performance has been assessed in a range of environments. To be of use across a range of environments, special attention must be paid to two crucially important characteristics of such instruments, i.e. their sensitivity and robustness. Thus, the objectives of this study were: 1. To compare the performance (in terms of their sensitivity and robustness) of the Duo Fluor and two other commercial fluorescence devices in laboratory conditions. 2. To assess the performance of the Duo Fluor in situ, in real time at a 450,000PE WwTW. Initially, the impact of quinine sulphate (QS), a highly fluorescent alkaloid with high quantum fluorescence yield, on peak T fluorescence in environmental waters was examined for the Duo Fluor and two commercially available, chamber-based fluorimeters, (F1) and (F2). The instruments' responses to three scenarios were assessed: 1. Deionised water (DW) spiked with QS (from 0.05 to 0.4 mg/L); 2. Environmental water (pond water, PW) spiked with QS (from 0.05 to 0.4 mg/L); 3. Different water samples from various environmental source. The results show that the facility to amend gain settings and the suitable choice of gain are crucial to obtaining reliable data on both peaks T and C in a wide range of water types. The Duo Fluor offers both of these advantages whilst commercially available instruments currently do not. The Duo Fluor was subsequently fixed at the final effluent (FE) discharge point of a WwTW and FE

  11. Characterization of an LED based photoreactor to degrade 4-chlorophenol in an aqueous medium using coumarin (C-343) sensitized TiO2.

    PubMed

    Ghosh, Jyoti P; Langford, Cooper H; Achari, Gopal

    2008-10-16

    A detailed performance evaluation of a simple high intensity LED based photoreactor exploiting a narrow wavelength range of the LED to match the spectrum of a dye in a photocatalysis system is reported. A dye sensitized (coumarin-343, lambda max = 446 nm) TiO 2 photocatalyst was used for the degradation of 4-chlorophenol (4-CP) in an aqueous medium using the 436 nm LED based photoreactor. The LED reactor performed competitively with a conventional multilamp reactor and sunlight in the degradation of 4-CP. Light intensities entering the reaction vessel were measured by conventional ferrioxalate actinometry. The results can be fitted by approximate first order kinetic behavior in this system. Hydroxyl radicals were detected by spin trapping EPR, and effects of OH radical quenchers on kinetics suggest that the reaction is initiated by these radicals or their equivalents. LEDs operating at competitive intensities offer a number of advantages to the photochemist or the environmental engineer via long life, efficient current to light conversion, narrow bandwidth, forward directed output, and direct current power for remote operation. Matching light source spectrum to chromophore is a key. PMID:18798604

  12. Infrared Targeting System (IRTS) demonstration

    NASA Astrophysics Data System (ADS)

    Ohair, Mark A.; Eucker, Shelly S.; Eucker, Brad A.; Lewis, Tim

    1992-02-01

    The objective of the Infrared Targeting System (IRTS) is to successfully demonstrate the mission performance that can be achieved in manned air-to-ground targeting applications utilizing a synergistic combination of state of the art active/passive infrared sensor and automatic target recognizer (ATR) technologies. The IRTS program is centered around a demonstration FLIR/Laser Radar/ATR (FLASHER). The FLASHER consists of a dual field of view (2 x 2 degree and 6 x 6 degree) second generation FLIR pixel mapped to a CO2 laser radar, with a FLIR ATR processor, a laser radar ATR processor, and a sensor fusion ATR processor. Following construction and laboratory testing of the IRTS, the system will be installed on a test aircraft and demonstrated in flight against realistic tactical, strategic, and special operations scenarios.

  13. Novel blue LED-based handheld fluorometer for detection of terrestrial algae on solid surfaces

    NASA Astrophysics Data System (ADS)

    Brechet, Eric; McStay, Daniel; Wakefield, Rachael D.; Campbell, Ian

    1998-09-01

    The application of an hand-held fluorometer used to monitor algal growth on stone surfaces is reported. The system is based on a modulated ultra-bright blue LED, used to induce chlorophyll-a fluorescence, as well as that of accessory pigments. With the addition of an encoding wheel and when linked to computer this system can produce real time map of the algae population on solid surface. The system has been shown to have a linear response to algal concentration, making it a viable tool for algal monitoring. The hand-held system is relatively immune to ambient light allowing it to be used on-site in various daylight conditions. Results from field and laboratory tests of the system on historically important sites and test samples are presented.

  14. Performance of short-range non-line-of-sight LED-based ultraviolet communication receivers.

    PubMed

    He, Qunfeng; Xu, Zhengyuan; Sadler, Brian M

    2010-06-01

    Utilizing an empirical path loss model proposed in the first paper of a two-part series, the bit error rate performance of short-range non-line-of-sight ultraviolet communication receivers is analyzed. Typical photodetector models and modulation formats are considered. Our results provide semi-analytical prediction of the achievable communication performance as a function of system and channel parameters, and serve as a basis for system design. PMID:20588347

  15. Modulation bandwidth enhancement of white-LED-based visible light communications using electrical equalizations

    NASA Astrophysics Data System (ADS)

    Kwon, D. H.; Yang, S. H.; Han, S. K.

    2015-01-01

    Utilizing the modulation capability of LEDs, there have been many studies about convergence technology to combine illumination and communication. The visible light communication (VLC) system has several advantages such as high security, immunity to RF interference and lower additional cost than comparing to LEDs just for illumination. However, modulation bandwidth of LEDs is not enough for various wireless communication systems. Since the commercial LEDs are designed only for lighting systems; we need an effort to enhance the modulation characteristics of LEDs. When the area of LED is increased, internal junction capacitance of LED is also increased depending on the area of LEDs and then the RC delay time of LED is increased. As a result, the modulation bandwidth of LEDs is limited by large RC delay time. In addition, frequency response of commercial white LED is degraded by the slow response time of the used yellow phosphor. Thus, modulation bandwidth of VLC system is limited to several MHz which is not enough to accommodate high data rate transmission. In this paper, we designed equalization circuit using RLC component for compensating the white LEDs frequency response. Also, we used blue filtering to improve frequency response of white LEDs, which is degraded by yellow phosphorescent component. Power loss by optical filtering and distance is compensated by convex lens. Consequently, we extend the modulation bandwidth of VLC system from 3 MHz to more than 180 MHz, and it allows NRZ-OOK data transmission up to 400 Mbps at 50 cm.

  16. Design and development of LED-based irregular leather area measuring machine

    NASA Astrophysics Data System (ADS)

    Adil, Rehan; Khan, Sarah Jamal

    2012-01-01

    Using optical sensor array, a precision motion control system in a conveyer follows the irregular shaped leather sheet to measure its surface area. In operation, irregular shaped leather sheet passes on conveyer belt and optical sensor array detects the leather sheet edge. In this way outside curvature of the leather sheet is detected and is then feed to the controller to measure its approximate area. Such system can measure irregular shapes, by neglecting rounded corners, ellipses etc. To minimize the error in calculating surface area of irregular curve to the above mentioned system, the motion control system only requires the footprint of the optical sensor to be small and the distance between the sensors is to be minimized. In the proposed technique surface area measurement of irregular shaped leather sheet is done by defining velocity and detecting position of the move. The motion controller takes the information and creates the necessary edge profile on point-to-point bases. As a result irregular shape of leather sheet is mapped and is then feed to the controller to calculate surface area.

  17. Design and development of LED-based irregular leather area measuring machine

    NASA Astrophysics Data System (ADS)

    Adil, Rehan; Khan, Sarah Jamal

    2011-12-01

    Using optical sensor array, a precision motion control system in a conveyer follows the irregular shaped leather sheet to measure its surface area. In operation, irregular shaped leather sheet passes on conveyer belt and optical sensor array detects the leather sheet edge. In this way outside curvature of the leather sheet is detected and is then feed to the controller to measure its approximate area. Such system can measure irregular shapes, by neglecting rounded corners, ellipses etc. To minimize the error in calculating surface area of irregular curve to the above mentioned system, the motion control system only requires the footprint of the optical sensor to be small and the distance between the sensors is to be minimized. In the proposed technique surface area measurement of irregular shaped leather sheet is done by defining velocity and detecting position of the move. The motion controller takes the information and creates the necessary edge profile on point-to-point bases. As a result irregular shape of leather sheet is mapped and is then feed to the controller to calculate surface area.

  18. LED-based nondirectional infrared transceiver for high-speed indoor wireless data communication

    NASA Astrophysics Data System (ADS)

    Chen, George C. K.; New, Wei L.; Yao, Jianping; Venkateswarlu, Ronda

    2001-10-01

    A Line of Sight, non-directed transceiver system was designed and constructed. The transmitter is composed of two types of LEDs and are tilted at 60 degree(s) to achieve uniform light distribution up to 50 degrees across a plane. The receiver is composed of multiple silicon-pin-photodiodes, transimpedance amplifiers, bandpass filter and AGC, and has a half field of view of 60 degree. Software was written to design uniform distribution on a horizontal plane for non-directed line-of-sight system. Experimental testing was conducted in a room with size 3.4m x 5.1m x 2.6m and measured optical power shows close correspondence to the simulated power distribution. Non-return-to zero signal of certain test codes were transmitted at 34 Mbps, and collected signals indicate that the eye is widely open in the eye diagram.

  19. Development of a non-invasive LED based device for adipose tissue thickness measurements in vivo

    NASA Astrophysics Data System (ADS)

    Volceka, K.; Jakovels, D.; Arina, Z.; Zaharans, J.; Kviesis, E.; Strode, A.; Svampe, E.; Ozolina-Moll, L.; Butnere, M. M.

    2012-06-01

    There are a number of techniques for body composition assessment in clinics and in field-surveys, but in all cases the applied methods have advantages and disadvantages. High precision imaging methods are available, though expensive and non-portable, however, the methods devised for the mass population, often suffer from the lack of precision. Therefore, the development of a safe, mobile, non-invasive, optical method that would be easy to perform, precise and low-cost, but also would offer an accurate assessment of subcutaneous adipose tissue (SAT) both in lean and in obese persons is required. Thereof, the diffuse optical spectroscopy is advantageous over the aforementioned techniques. A prototype device using an optical method for measurement of the SAT thickness in vivo has been developed. The probe contained multiple LEDs (660nm) distributed at various distances from the photo-detector which allow different light penetration depths into the subcutaneous tissue. The differences of the reflected light intensities were used to create a non-linear model, and the computed values were compared with the corresponding thicknesses of SAT, assessed by B-mode ultrasonography. The results show that with the optical system used in this study, accurate results of different SAT thicknesses can be obtained, and imply a further potential for development of multispectral optical system to observe changes of SAT thickness as well as to determine the percentage of total body fat.

  20. Single LED-based device to perform widefield fluorescence imaging and photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Grecco, Clovis; Buzzá, Hilde H.; Stringasci, Mirian D.; Andrade, Cintia T.; Vollet-Filho, Jose D.; Pratavieira, Sebastião.; Zanchin, Anderson L.; Tuboy, Aparecida M.; Bagnato, Vanderlei S.

    2015-06-01

    Photodynamic therapy (PDT) is a treatment modality that can be indicated for several cancer types and pre-cancer lesions. One of the main applications of PDT is the treatment of superficial skin lesions such as basal cell carcinoma, Bowen's disease and actinic keratosis. Three elements are necessary in PDT, a photosensitizer (PS); light at specific wavelength to be absorbed by the PS, and molecular oxygen. A typical PS used for skin lesion is protoporphyrin IX (PpIX), which is an intrinsic PS; its production is stimulated by a pro-drug, such as 5-aminolevulinic acid (ALA). Before starting a treatment, it is very important to follow up the PpIX production (to ensure that enough PS was produced prior to a PDT application) and, during a PDT session, to monitor its photodegradation (as it is evidence of the photodynamic effect taking place). The aim of this paper is to present a unique device, LINCE (MMOptics - São Carlos, Brazil), that brings together two probes that can, respectively, allow for fluorescence imaging and work as a light source for PDT treatment. The fluorescence probe of the system is optically based on 400 nm LED (light emitting diodes) arrays that allow observing the fluorescence emission over 450 nm. The PDT illumination probe options are constituted of 630 nm LED arrays for small areas and, for large areas, of both 630 nm and 450 nm LED arrays. Joining both functions at the same device makes PDT treatment simpler, properly monitorable and, hence, more clinically feasible. LINCE has been used in almost 1000 PDT treatments of superficial skin lesions in Brazil, with 88.4% of clearance of superficial BCC.

  1. The Global Light System for the JEM-EUSO detector

    NASA Astrophysics Data System (ADS)

    Wiencke, Lawrence; Adams, James; Christl, Mark; Eser, Johannes; Sarazin, Fred

    The origin of cosmic rays at the 100 EeV scale is unknown. The Extreme Universe Space Observatory on the Japanese Experiment Module (JEM-EUSO) instrument, planned for the International Space Station, will record the optical signatures generated by the interaction of extreme energy cosmic rays in the earth’s atmosphere. To address the measurement challenge posed by the low flux of particles at these energies, a global light system (GLS) of calibrated UV light sources will be deployed around the globe to calibrate the instrument in space. The GLS network will consist of 12 ground stations. Each will have a Xe flasher and 6 will have steered pulsed UV lasers in addition to their flashers. During dark periods, the GLS stations will be activated as the ISS passes overhead to will generate flashes and tracks that will be recorded by JEM-EUSO. This network will be supplemented by an aircraft-based system flown monthly over the open ocean. The GLS will have many applications. For example, the intrinsic brightness of the GLS flashers and lasers can be set to match the equivalent intrinsic brightness of 100 EeV cosmic ray extensive air showers. To test detector triggering and angular resolution, the lasers will be pointed at astrophysical objects of interest that are potential sources of cosmic rays. A ground based prototype GLS station with a flasher and laser will be used to test the TUS detector on the Lomonosov satellite. A prototype of the aircraft based GLS system will be flown under the EUSO-Balloon pathfinder.

  2. Design of high power LED-based UVA emission system and a photosensitive substance for clinical application in corneal radiation

    NASA Astrophysics Data System (ADS)

    Mota, Alessandro D.; Cestari, André M.; de Oliveira, André O.; Oliveira, Anselmo G.; Terruggi, Cristina H. B.; Rossi, Giuliano; Castro, Jarbas C.; Ligabô, João. P. B.; Ortega, Tiago A.; Rosa, Tiago

    2015-09-01

    This work presents an innovative cross-linking procedure to keratoconus treatment, a corneal disease. It includes the development of an ultraviolet controlled emission portable device based on LED source and a new formulation of a photosensitive drug called riboflavin. Thus new formulation improves drug administration by its transepithelial property. The UV reaction with riboflavin in corneal tissue leads to a modification of corneal collagen fibers, turning them more rigid and dense, and consequently restraining the advance of the disease. We present the control procedures to maintain UV output power stable up to 45mw/cm2, the optical architecture that leads to a homogeneous UV spot and the new formulation of Riboflavin.

  3. Long term NO2 measurements in Hong Kong using LED based Long Path Differential Optical Absorption Spectroscopy

    NASA Astrophysics Data System (ADS)

    Chan, K. L.; Pöhler, D.; Kuhlmann, G.; Hartl, A.; Platt, U.; Wenig, M. O.

    2011-11-01

    In this study we present the first long term measurements of atmospheric nitrogen dioxide (NO2) using a LED based Long Path Differential Optical Absorption Spectroscopy (LP-DOAS) instrument. This instrument is measuring continuously in Hong Kong since December 2009, first in a setup with a 550 m absorption path and then with a 3820 m path at about 30 m to 50 m above street level. The instrument is using a high power blue light LED with peak intensity at 450 nm coupled into the telescope using a Y-fibre bundle. The LP-DOAS instrument measures NO2 concentrations in the Kowloon Tong and Mong Kok district of Hong Kong and we compare the measurement results to concentrations reported by monitoring stations operated by the Hong Kong Environmental Protection Department in that area. Hourly averages of coinciding measurements are in reasonable agreement (R = 0.74). Furthermore, we used the long-term data set to validate the Ozone Monitoring Instrument (OMI) NO2 data product. Monthly averaged LP-DOAS and OMI measurements correlate well (R = 0.84) when comparing the data for the OMI overpass time. We analyzed weekly patterns in both data sets and found that the LP-DOAS detects a clear weekly cycle with a reduction on weekends during rush hour peaks, whereas OMI is not able to observe this weekly cycle due to its fix overpass time.

  4. Measurements of atmospheric NO3 radicals in Hefei using LED-based long path differential optical absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Xue, Lu; Min, Qin; Pin-Hua, Xie; Jun, Duan; Wu, Fang; Liu-Yi, Ling; Lan-Lan, Shen; Jian-Guo, Liu; Wen-Qing, Liu

    2016-02-01

    NO3 radicals accumulate during the night, thereby being the most critical night oxidant. Owing to the low concentration and dramatic variation, the detection of atmospheric NO3 radicals is still challenging. In this paper, an LED-based Long Path Differential Optical Absorption Spectroscopy (LPDOAS) instrument is developed for measuring the atmospheric NO3 radicals. This instrument is composed of a Schmidt-Cassegrain telescope, a combined emitting and receiving fiber, and a red LED equipped with a thermostat, and has a center wavelength of 660 nm, covering the NO3 strongest absorption peak (662 nm). The influence of LED temperature fluctuations is discussed. The temperature of the LED lamp with a home-made thermostat is tested, showing a stability of ±0.1 °C. The principle and fitting analyses of LED-LPDOAS are presented. A retrieval example and a time series of NO3 radical concentrations with good continuity for one night are shown. The detection limit of NO3 for 2.6-km optical path is about 10 ppt. Project supported by the “Strategic Priority Research Program” of the Chinese Academy of Sciences (Grant Nos. XDB05040200 and XDB05010500).

  5. Electrically Tunable Valley-Light Emitting Diode (vLED) Based on CVD-Grown Monolayer WS2.

    PubMed

    Yang, Weihuang; Shang, Jingzhi; Wang, Jianpu; Shen, Xiaonan; Cao, Bingchen; Peimyoo, Namphung; Zou, Chenji; Chen, Yu; Wang, Yanlong; Cong, Chunxiao; Huang, Wei; Yu, Ting

    2016-03-01

    Owing to direct band gap and strong spin-orbit coupling, monolayer transition-metal dichalcogenides (TMDs) exhibit rich new physics and great applicable potentials. The remarkable valley contrast and light emission promise such two-dimensional (2D) semiconductors a bright future of valleytronics and light-emitting diodes (LEDs). Though the electroluminescence (EL) has been observed in mechanically exfoliated small flakes of TMDs, considering real applications, a strategy that could offer mass-product and high compatibility is greatly demanded. Large-area and high-quality samples prepared by chemical vapor deposition (CVD) are perfect candidates toward such goal. Here, we report the first demonstration of electrically tunable chiral EL from CVD-grown monolayer WS2 by constructing a p-i-n heterojunction. The chirality contrast of the overall EL reaches as high as 81% and can be effectively modulated by forward current. The success of fabricating valley LEDs based on CVD WS2 opens up many opportunities for developing large-scale production of unconventional 2D optoelectronic devices. PMID:26854533

  6. A blue-LED-based device for selective photocoagulation of superficial abrasions: theoretical modeling and in vivo validation

    NASA Astrophysics Data System (ADS)

    Rossi, Francesca; Pini, Roberto; De Siena, Gaetano; Massi, Daniela; Pavone, Francesco S.; Alfieri, Domenico; Cannarozzo, Giovanni

    2010-02-01

    The blue light (~400 nm) emitted by high power Light Emitting Diodes (LED) is selectively absorbed by the haemoglobin content of blood and then converted into heat. This is the basic concept in setting up a compact, low-cost, and easy-to-handle photohaemostasis device for the treatment of superficial skin abrasions. Its main application is in reducing bleeding from superficial capillary vessels during laser induced aesthetic treatments, such as skin resurfacing, thus reducing the treatment time and improving aesthetic results (reduction of scar formation). In this work we firstly present the preliminary modeling study: a Finite Element Model (FEM) of the LED induced photothermal process was set up, in order to estimate the optimal wavelength and treatment time, by studying the temperature dynamics in the tissue. Then, a compact, handheld illumination device has been designed: commercially available high power LEDs emitting in the blue region were mounted in a suitable and ergonomic case. The prototype was tested in the treatment of dorsal excoriations in rats. Thermal effects were monitored by an infrared thermocamera, experimentally evidencing the modest and confined heating effects and confirming the modeling predictions. Objective observations and histopathological analysis performed in a follow-up study showed no adverse reactions and no thermal damage in the treated areas and surrounding tissues. The device was then used in human patients, in order to stop bleeding during Erbium laser skin resurfacing procedure. By inducing LED-based photocoagulation, the overall treatment time was shortened and scar formation was reduced, thus enhancing esthetic effect of the laser procedure.

  7. A LED-based method for monitoring NAD(P)H and FAD fluorescence in cell cultures and brain slices.

    PubMed

    Rösner, Jörg; Liotta, Agustin; Schmitz, Dietmar; Heinemann, Uwe; Kovács, Richard

    2013-01-30

    Nicotinamide- and flavine-adenine-dinucleotides (NAD(P)H and FADH₂) are electron carriers involved in cellular energy metabolism and in a multitude of enzymatic processes. As reduced NAD(P)H and oxidised FAD molecules are fluorescent, changes in tissue auto-fluorescence provide valuable information on the cellular redox state and energy metabolism. Since fluorescence excitation, by mercury arc lamps (HBO) is inherently coupled to photo-bleaching and photo-toxicity, microfluorimetric monitoring of energy metabolism might benefit from the replacement of HBO lamps by light emitting diodes (LEDs). Here we describe a LED-based custom-built setup for monitoring NAD(P)H and FAD fluorescence at the level of single cells (HEK293) and of brain slices. We compared NAD(P)H bleaching characteristics with two light sources (HBO lamp and LED) as well as sensitivity and signal to noise ratio of three different detector types (multi-pixel photon counter (MPPC), photomultiplier tube (PMT) and photodiode). LED excitation resulted in reduced photo-bleaching at the same fluorescence output in comparison to excitation with the HBO lamp. Transiently increasing LED power resulted in reversible bleaching of NAD(P)H fluorescence. Recovery kinetics were dependent on metabolic substrates indicating coupling of NAD(P)H fluorescence to metabolism. Electrical stimulation of brain slices induced biphasic redox changes, as indicated by NAD(P)H/FAD fluorescence transients. Increasing the gain of PMT and decreasing the LED power resulted in similar sensitivity as obtained with the MPPC and the photodiode, without worsening the signal to noise ratio. In conclusion, replacement of HBO lamp with LED might improve conventional PMT based microfluorimetry of tissue auto-fluorescence. PMID:23142181

  8. Application of a LED-based reflectance sensor for the assessing in situ the lycopene content of tomatoes (Lycopersicon esculentum Mill.)

    NASA Astrophysics Data System (ADS)

    Mignani, Anna G.; Ciaccheri, Leonardo; Mencaglia, Andrea A.; Tuccio, Lorenza; Agati, Giovanni

    2015-05-01

    Nondestructive in situ determination of the antioxidant lycopene of fresh tomato fruits is of large interest for the growers, willing to optimize the harvest time for high quality products. For this, we developed a portable LED-based colorimeter which was able to measure reflectance spectra of whole tomatoes in the 400-750 nm range. The tomato skins from the same samples were then frozen in liquid nitrogen, extracted with an acetone/ethanol/hexane mixture and analyzed by means of a spectrophotometer for their lycopene content. Concentration of lycopene was varying between 70 and 550 mg/Kg fresh weight skin. Partial Least Square regression was used to correlate spectral data to the tomato lycopene content. The multivariate processing of the reflectance data showed that lycopene content could be nicely predicted with a coefficient of determination R2=0.945 and a root mean square error of cross-validation RMSECV=57 mg/Kg skin fresh weight. These results suggest that portable, low-cost and compact LED-based sensors appear to be promising instruments for the nondestructive assessment of tomato lycopene even in the field.

  9. Two-flash method using red and green lasers in a velocity measuring system

    NASA Astrophysics Data System (ADS)

    Li, Zhongke; Li, Fubao; Yue, Kaiduan; Yi, Yaxing

    2008-12-01

    In order to acquire sequence images in PIV measurement system of continuous clashing flow of water, two laser flashers, the red one and the green one, are used in PIV measurement system. After the digital camera is triggered, the two flashers flash in a short interval during the exposure period. The red light and the green light illuminate the same region so that the image records the movements of tracing particles in two colors. Using digital image process technology, two images, the red one and the green one, can be obtained from the original image. Based on the two images, the flow field parameters can be calculated. The method possesses predominant advantages: high speed field can be measured using an ordinary camera and the two images have determinate time labels, so the moving direction of the particles can be determined easily. The main steps of the method include the transition from Bayer matrix to RGB matrix, the pretreatment of the images, the analyzation of the velocity and the arrangement of the results.

  10. 1.6 Gbit/s phosphorescent white LED based VLC transmission using a cascaded pre-equalization circuit and a differential outputs PIN receiver.

    PubMed

    Huang, Xingxing; Wang, Zhixin; Shi, Jianyang; Wang, Yiguang; Chi, Nan

    2015-08-24

    We proposed a cascaded amplitude equalizer used for high speed visible light communications (VLC) system. With the cascaded pre-equalization circuit, the -3dB bandwidth of VLC system can be extended from 17MHz to 366MHz using a commercially available phosphorescent white LED, a blue filter and a differential outputs PIN receiver. The data rate is 1.60Gbit/s exploiting 16QAM-OFDM with 400MHz modulation bandwidth over 1m free-space transmission under pre-forward error correction (pre-FEC) limit of 3.8 × 10(-3). To our knowledge, this is the highest data rate ever achieved by using a commercially available phosphorescent white LED in VLC system. PMID:26368178

  11. Challenges and opportunities in LED based lighting

    NASA Astrophysics Data System (ADS)

    Panahi, Allen

    2013-05-01

    Solid state lighting technology has made great advances over the last decade and has become the technology of choice to displace legacy incandescent and as well as the more efficient fluorescent lights. While efficiencies have been improved and cost of the LEDs has been steadily lowered still many challenges exist in the thermal, electrical, optical, and packaging implementations.

  12. LED-based NDIR natural gas analyzer

    NASA Astrophysics Data System (ADS)

    Fanchenko, Sergey; Baranov, Alexander; Savkin, Alexey; Sleptsov, Vladimir

    2016-03-01

    A new generation of the light-emitting diodes (LEDs) and photodiodes (PDs) was used recently to develop an open path non-dispersive infrared (NDIR) methane analyzer. The first open path detector prototype was constructed using LEDs for measurement and reference channels, accordingly, and first measurements for methane gas have been performed using optical paths of the order of several meters [3]. The natural gas consists of several first alkanes, mainly methane, and it is important to have a possibility of measuring all of them. In the present work we report the results of NDIR measurements for propane-butane mixture and new measurements of methane using LEDs for measurement and reference channels at 2300 and 1700 nm wavelengths, accordingly. The necessity of the double beam scheme is demonstrated and obtained results for methane and propane-butane mixture are compared.

  13. Global Light System for JEM-EUSO

    NASA Technical Reports Server (NTRS)

    Christl, Mark

    2013-01-01

    The Global Light System (GLS) is a network of ground-based Xenon flash lamps and steered UV lasers to validate the key functions of the JEM-EUSO instrument. These functions include triggering efficiency, the accuracy of intrinsic luminosity measurements, and the reconstructed pointing direction accuracy. GLS units will generate benchmark optical signatures in the atmosphere with similar characteristics to the optical signals of cosmic ray EASs. The lasers will generate tracks and the flashers will generate point flashes. But unlike air showers, the number, energy, precise time, direction (lasers) can be specified. JEM-EUSO will reconstruct the pointing directions of the lasers and the energy of the lasers and flash lamps to monitor the detector's triggers, and accuracy of energy and direction reconstruction. 12 GLS units will be deployed at selected sites around the globe. The JEM-EUSO footprint will pass over a GLS unit on average once per (near) moonless night under clear conditions for appropriately selected sites. The 12 units will be supplemented by campaign style measurements with an airborne unit that will be flown over the open ocean at selected altitudes under JEM-EUSO. A GLS prototype in an airplane will support a high-altitude balloon flight in 2014 of a proto-type JEM-EUSO telescope. We will describe the concept and system design and report on the status of prototyping and the selection process for candidates sites.

  14. High-Modulation-Speed LEDs Based on III-Nitride

    NASA Astrophysics Data System (ADS)

    Chen, Hong

    III-nitride InGaN light-emitting diodes (LEDs) enable wide range of applications in solid-state lighting, full-color displays, and high-speed visible-light communication. Conventional InGaN quantum well LEDs grown on polar c-plane substrate suffer from quantum confined Stark effect due to the large internal polarization-related fields, leading to a reduced radiative recombination rate and device efficiency, which limits the performance of InGaN LEDs in high-speed communication applications. To circumvent these negative effects, non-trivial-cavity designs such as flip-chip LEDs, metallic grating coated LEDs are proposed. This oral defense will show the works on the high-modulation-speed LEDs from basic ideas to applications. Fundamental principles such as rate equations for LEDs/laser diodes (LDs), plasmonic effects, Purcell effects will be briefly introduced. For applications, the modal properties of flip-chip LEDs are solved by implementing finite difference method in order to study the modulation response. The emission properties of highly polarized InGaN LEDs coated by metallic gratings are also investigated by finite difference time domain method.

  15. UV-LED-based charge control for LISA

    NASA Astrophysics Data System (ADS)

    Olatunde, Taiwo; Shelley, Ryan; Chilton, Andrew; Ciani, Giacomo; Mueller, Guido; Conklin, John

    2014-03-01

    The test masses inside the LISA gravitational reference sensors (GRS) must maintain almost pure geodesic motion for gravitational waves to be successfully detected. The residual accelerations have to stay below 3fm/s2/rtHz at all frequencies between 0.1 and 3 mHz. One of the well known noise sources is associated with the charges on the test masses which couple to stray electrical potentials and external electro-magnetic fields. The LISA pathfinder (LPF) will use Hg-discharge lamps emitting mostly around 253 nm to discharge the test masses via photoemission in its 2015/16 flight. A future LISA mission launched around 2030 will likely replace the lamps with newer UV-LEDs. UV-LEDs have a lower mass, a better power efficiency, and are smaller than their Hg counterparts. Furthermore, the latest generation produces light at 240 nm, with energy well above the work function of pure gold. I will describe a preliminary design for effective charge control through photoelectric effect by using these LEDs. The effectiveness of this method is verified by taking Quantum Efficiency (QE) measurements which relate the number of electrons emitted to the number of photons incident on the Au test mass surface. This presentation addresses our initial results and future plans which includes implementation and testing in the UF torsion pendulum and space-qualification in a small satellite mission which will launch in the summer of 2014, through a collaboration with Stanford, KACST, and NASA Ames Research Center.

  16. LED based on alternating benzene-furan oligomers.

    PubMed

    Song, Senchuan; Chen, Jianghan; Pan, Wenlong; Song, Hucacan; Shi, Huahong; Mai, Yuliang; Wen, Wu

    2017-01-01

    A series of conjugated-chain compounds which contain two furan units and more than three other aromatic ring units were synthesized by two different methods, their UV-visible absorption coefficient (ε), maximum absorption wavelengths (λa), fluorescence emission wavelengths (λe), stokes shift and quantum yields (Φ) were determined, the relationships between the molecular structures and the effects of spectral behaviors were discussed. Meanwhile, the excitation spectrum and emission spectrum of 2b and 2d in solid and in ethyl acetate were respectively recorded, the thermal stability of 2b and 2d was evaluated, and the fluorescence emission behaviors of two light emitting diodes, fabricated with 2b and 2d as phosphors, were investigated. The results showed that most of target compounds can perform high fluorescence emission ability, compounds 2b and 2d can perform higher thermal stability under 350°C and they are suitable for making light emitting diode as phosphors, the light emitting diodes fabricated with 2b and 2d can show higher fluorescence emission ability. Therefore, those compounds are worthy of further being developed as fluorescent emission materials. PMID:27428602

  17. A quantitative dimming method for LED based on PWM

    NASA Astrophysics Data System (ADS)

    Wang, Jiyong; Mou, Tongsheng; Wang, Jianping; Tian, Xiaoqing

    2012-10-01

    Traditional light sources were required to provide stable and uniform illumination for a living or working environment considering performance of visual function of human being. The requirement was always reasonable until non-visual functions of the ganglion cells in the retina photosensitive layer were found. New generation of lighting technology, however, is emerging based on novel lighting materials such as LED and photobiological effects on human physiology and behavior. To realize dynamic lighting of LED whose intensity and color were adjustable to the need of photobiological effects, a quantitative dimming method based on Pulse Width Modulation (PWM) and light-mixing technology was presented. Beginning with two channels' PWM, this paper demonstrated the determinacy and limitation of PWM dimming for realizing Expected Photometric and Colorimetric Quantities (EPCQ), in accordance with the analysis on geometrical, photometric, colorimetric and electrodynamic constraints. A quantitative model which mapped the EPCQ into duty cycles was finally established. The deduced model suggested that the determinacy was a unique individuality only for two channels' and three channels' PWM, but the limitation was an inevitable commonness for multiple channels'. To examine the model, a light-mixing experiment with two kinds of white LED simulated variations of illuminance and Correlation Color Temperature (CCT) from dawn to midday. Mean deviations between theoretical values and measured values were obtained, which were 15lx and 23K respectively. Result shows that this method can effectively realize the light spectrum which has a specific requirement of EPCQ, and provides a theoretical basis and a practical way for dynamic lighting of LED.

  18. Development of a Tunable LED-Based Colorimetric Source

    PubMed Central

    Brown, Steven W.; Santana, Carlos; Eppeldauer, George P.

    2002-01-01

    A novel, spectrally tunable light-source utilizing light emitting diodes (LEDs) for radiometric, photometric, and colorimetric applications is described. The tunable source can simulate standard sources and can be used as a transfer source to propagate photometric and colorimetric scales from calibrated reference instruments to test artifacts with minimal increase in uncertainty. In this prototype source, 40 LEDs with 10 different spectral distributions were mounted onto an integrating sphere. A voltage-to-current control circuit was designed and implemented, enabling independent control of the current sent to each set of four LEDs. The LEDs have been characterized for stability and dependence on drive current. The prototype source demonstrates the feasibility of development of a spectrally tunable LED source using LEDs with up to 40 different spectral distributions. Simulations demonstrate that such a source would be able to approximate standard light-source distributions over the visible spectral range—from 380 nm to 780 nm—with deviations on the order of 2 %. The tunable LED source can also simulate spectral distributions of special sources such as discharge lamps and display monitors. With this tunable source, a test instrument can be rapidly calibrated against a variety of different source distributions tailored to the anticipated uses of the artifact. Target uncertainties for the calibration of test artifacts are less than 2 % in luminance and 0.002 in chromaticity for any source distribution.

  19. Integrated LED-based luminare for general lighting

    DOEpatents

    Dowling, Kevin J.; Lys, Ihor A.; Roberge, Brian; Williamson, Ryan C.; Roberts, Ron; Datta, Michael; Mollnow, Tomas; Morgan, Frederick M.

    2013-03-05

    Lighting apparatus and methods employing LED light sources are described. The LED light sources are integrated with other components in the form of a luminaire or other general purpose lighting structure. Some of the lighting structures are formed as Parabolic Aluminum Reflector (PAR) luminaires, allowing them to be inserted into conventional sockets. The lighting structures display beneficial operating characteristics, such as efficient operation, high thermal dissipation, high output, and good color mixing.

  20. Integrated LED-based luminaire for general lighting

    DOEpatents

    Dowling, Kevin J.; Lys, Ihor A.; Williamson, Ryan C.; Roberge, Brian; Roberts, Ron; Morgan, Frederick; Datta, Michael Jay; Mollnow, Tomas Jonathan

    2016-08-30

    Lighting apparatus and methods employing LED light sources are described. The LED light sources are integrated with other components in the form of a luminaire or other general purpose lighting structure. Some of the lighting structures are formed as Parabolic Aluminum Reflector (PAR) luminaires, allowing them to be inserted into conventional sockets. The lighting structures display beneficial operating characteristics, such as efficient operation, high thermal dissipation, high output, and good color mixing.

  1. Laser Station Design for the Global Light System for the Planned JEM-EUSO Extreme Universe Observatory

    NASA Astrophysics Data System (ADS)

    Geier, Christine; Burg, Martin; Bigler, Colton; Wiencke, Lawrence

    2014-03-01

    The JEM-EUSO Global Light System (GLS) will provide ground-based calibration and monitoring for the JEM-EUSO detector planned for the International Space Station (ISS). JEM-EUSO will use the atmosphere as a giant calorimeter to measure Ultra High Energy Cosmic Rays (UHECRs). The GLS will include twelve ground stations. All twelve will have calibration xenon flash bulbs and six will have steered lasers. The GLS laser stations will generate optical signatures by creating light tracks across the JEM-EUSO field of view. The lasers and xenon flashers will be used to benchmark the JEM-EUSO instrument during its mission since energy, duration and orientation of those sources can be controlled. In this presentation, we will describe a project to design and build a working prototype of a GLS laser station. In order to meet the specifications set forth in the design requirements, our design incorporates remote operation capability, solar power, and a controlled internal climate. These components are in addition to the laser and calibration system and steering mechanism. All components will be combined in a robust, durable design that can be deployed and operated in remote locations across the globe.

  2. Positioning of ground-based Global Light System stations around the World for the JEM-EUSO mission

    NASA Astrophysics Data System (ADS)

    Norman, Zachary

    2013-04-01

    The astrophysical origins of the Extreme Energy Cosmic Rays (EECRs - E >10^20 eV) remain a matter of debate. Data obtained on EECRs is sparse, due to the very low flux reaching the Earth. The Extreme Universe Space Observatory on board the Japanese Experiment Module (JEM-EUSO) on the International Space Station (ISS) will measure the properties of EECRs by recording the UV light produced by the air showers in Earth's atmosphere from space. At these extremely high energies, there is no way to calibrate the detector and test its operation with man-made accelerators. However, it is possible to induce the detector to see a similar amount of light by using an array of Global Light System (GLS) stations, which will use xenon flashers and lasers. The GLS locations need to be representative of the different climates around the World, because the development of the air showers depends upon the general properties of the atmosphere where it occurs. In this context, a program was developed to predict when a given GLS station is able to fire test shots within the field of view of the JEM-EUSO detector as the ISS flies over. This program takes into account the trajectory of the ISS, the relative positions of the Sun and the Moon, as well as the average cloud cover over the candidate sites.

  3. The Photomultiplier Tube Calibration System of the MicroBooNE Experiment

    SciTech Connect

    Conrad, J.; Jones, B. J.P.; Moss, Z.; Strauss, T.; Toups, M.

    2015-06-03

    We report on the design and construction of a LED-based fiber calibration system for large liquid argon time projection detectors. This system was developed to calibrate the optical systems of the MicroBooNE experiment. As well as detailing the materials and installation procedure, we provide technical drawings and specifications so that the system may be easily replicated in future LArTPC detectors.

  4. Utilization of space technology for terrestrial solar power applications

    NASA Technical Reports Server (NTRS)

    Yasui, R. K.; Patterson, R. E.

    1974-01-01

    A description is given of the evolution of photovoltaic power systems designed and built for terrestrial applications, giving attention to problem areas which are currently impeding the further development of such systems. The rooftop testing of surplus solar panels is considered along with solar powered seismic observatories, solar powered portable radio sets, and design considerations identified from past experience. Present activities discussed are related to a solar powered on-shore beacon flasher system, a solar powered buoy, and a solar powered beacon flasher buoy.

  5. Experimental evaluation of LED-based solar blind NLOS communication links.

    PubMed

    Chen, Gang; Abou-Galala, Feras; Xu, Zhengyuan; Sadler, Brian M

    2008-09-15

    Experimental results are reported demonstrating non-line of sight short-range ultraviolet communication link losses, and performance of photon counting detectors, operating in the solar blind spectrum regime. We employ light emitting diodes with divergent beams, a solar blind filter, and a wide field-of-view detector. Signal and noise statistics are characterized, and receiver performance is demonstrated. The effects of transmitter and receiver elevation angles, separation distance, and path loss are included. PMID:18795043

  6. LED based evanescent wave fiber optic sensor technique to detect Fe+2 concentration

    NASA Astrophysics Data System (ADS)

    Kulkarni, V. K.; Bendigeri, H. H.; Kulkarni, R. M.

    2016-05-01

    In this paper we have reported the development of a very easy and cost effective fiber optic sensor on the basis of evanescent wave absorption technique to detect ferrous Fe+2 using high quality light emitting diode (LED). In this method, unclad portion of the fiber was used as sensing element which is exploited to surrounding media consisting Fe+2 ions. Highly sensitive detector has been used to detect the output power of light guided through unclad optical fiber. Graph revealed that, developed sensor is highly sensitive over the dynamic range of concentration from 0.1ppm to 100ppm

  7. Design and implementation of organic LED-based displays for signage application

    NASA Astrophysics Data System (ADS)

    Sharma, Pratibha; Kwok, Harry

    2006-06-01

    Organic light-emitting diodes (OLEDs) have been utilized successfully for various applications such as microdisplays in cell-phones and digital cameras. However, the application of OLEDs for large area signage displays has not yet been established. This paper presents novel design techniques for implementing OLEDs as light sources for signage application. The designs are examined on the basis of signage uniformity, cost and manufacturing complexity. Advantages and limitations of each design are described. It is determined that a trade-off is required to choose a design for implementation. After evaluation and comparison of the designs, the most optimal design is chosen and implemented. Measurement results with the optimal design are described.

  8. High-power LEDs based on InGaAsP/InP heterostructures

    SciTech Connect

    Rakovics, V.; Imenkov, A. N.; Sherstnev, V. V.; Serebrennikova, O. Yu.; Il’inskaya, N. D.; Yakovlev, Yu. P.

    2014-12-15

    High-power light-emitting diodes (LEDs) with mesa diameters of 100, 200, and 300 μm are developed on the basis of InGaAsP/InP heterostructures. The mesas are close in shape to a truncated cone with a generatrix inclination angle of ∼45° in the vicinity of the active region of the LED, with a ring etched around the mesa serving as a reflector. The emission spectra and directivity patterns of these LEDs are studied in a wide range of current densities and it is shown that radiative recombination is dominant to a current density of ∼5000 A/cm{sup 2}, which makes these structures promising for the development of high-power LEDs. An emission power of ∼14 mW is obtained in the continuous-wave mode (I = 0.2 A, λ = 1.1 μm), and that of 77 mW, in the pulsed mode (I = 2 A, λ = 1.1 μm), which corresponds to external quantum efficiencies of 6.2 and 3.4%, respectively.

  9. Optimization of LED-based non-imaging optics with orthogonal polynomial shapes

    NASA Astrophysics Data System (ADS)

    Brick, Peter; Wiesmann, Christopher

    2012-10-01

    Starting with a seminal paper by Forbes [1], orthogonal polynomials have received considerable interest as descriptors of lens shapes for imaging optics. However, there is little information on the application of orthogonal polynomials in the field of non-imaging optics. Here, we consider fundamental cases related to LED primary and secondary optics. To make it most realistic, we avoid many of the simplifications of non-imaging theory and consider the full complexity of LED optics. In this framework, the benefits of orthogonal polynomial surface description for LED optics are evaluated in comparison to a surface description by widely used monomials.

  10. Final LDRD report :ultraviolet water purification systems for rural environments and mobile applications.

    SciTech Connect

    Banas, Michael Anthony; Crawford, Mary Hagerott; Ruby, Douglas Scott; Ross, Michael P.; Nelson, Jeffrey Scott; Allerman, Andrew Alan; Boucher, Ray

    2005-11-01

    We present the results of a one year LDRD program that has focused on evaluating the use of newly developed deep ultraviolet LEDs in water purification. We describe our development efforts that have produced an LED-based water exposure set-up and enumerate the advances that have been made in deep UV LED performance throughout the project. The results of E. coli inactivation with 270-295 nm LEDs are presented along with an assessment of the potential for applying deep ultraviolet LED-based water purification to mobile point-of-use applications as well as to rural and international environments where the benefits of photovoltaic-powered systems can be realized.

  11. Advanced helmet vision system (AHVS) integrated night vision helmet mounted display (HMD)

    NASA Astrophysics Data System (ADS)

    Ashcraft, Todd W.; Atac, Robert

    2012-06-01

    Gentex Corporation, under contract to Naval Air Systems Command (AIR 4.0T), designed the Advanced Helmet Vision System to provide aircrew with 24-hour, visor-projected binocular night vision and HMD capability. AHVS integrates numerous key technologies, including high brightness Light Emitting Diode (LED)-based digital light engines, advanced lightweight optical materials and manufacturing processes, and innovations in graphics processing software. This paper reviews the current status of miniaturization and integration with the latest two-part Gentex modular helmet, highlights the lessons learned from previous AHVS phases, and discusses plans for qualification and flight testing.

  12. Assessing the Performance of LED-Based Flashlights Available in the Kenyan Off-Grid Lighting Market

    SciTech Connect

    Tracy, Jennifer; Jacobson, Arne; Mills, Evan

    2010-03-02

    Low cost rechargeable flashlights that use LED technology are increasingly available in African markets. While LED technology holds promise to provide affordable, high quality lighting services, the widespread dissemination of low quality products may make it difficult to realize this potential. This study includes performance results for three brands of commonly available LED flashlights that were purchased in Kenya in 2009. The performance of the flashlights was evaluated by testing five units for each of the three brands. The tests included measurements of battery capacity, time required to charge the battery, maximum illuminance at one meter, operation time and lux-hours from a fully charged battery, light distribution, and color rendering. All flashlights tested performed well below the manufacturers? rated specifications; the measured battery capacity was 30-50percent lower than the rated capacity and the time required to fully charge the battery was 6-25percent greater than the rated time requirement. Our analysis further shows that within each brand there is considerable variability in each performance indicator. The five samples within a single brand varied from each other by as much as 22percent for battery capacity measurements, 3.6percent for the number of hours required for a full charge, 23percent for maximum initial lux, 38percent for run time, 11percent for light distribution and by as much as 200percent for color rendering. Results obtained are useful for creating a framework for quality assurance of off-grid LED products and will be valuable for informing consumers, distributors and product manufacturers about product performance.

  13. Surface aspects of discolouration in Bisphenol A Polycarbonate (BPA-PC), used as lens in LED-based products

    NASA Astrophysics Data System (ADS)

    Yazdan Mehr, M.; van Driel, W. D.; Udono, H.; Zhang, G. Q.

    2014-11-01

    The surface-related reactions during discolouration of Bisphenol A Polycarbonate (BPA-PC), used as LED lens plates, under thermal stress are studied. X-ray photoelectron spectroscopy (XPS) has been used to monitor the changes in the surface chemistry of BPA-PC plates over a temperature range of 100-140 °C for a period up to 3000 h. Increasing time under thermal stress is associated with the discolouration, and increase in the yellowing index (YI) of PC plastic lens. The XPS results show that discolouration is associated with oxidation at the surface, finding a significant increase in the signal ratio O1s/C1s in the XPS spectra of degraded specimens. During thermal ageing, the Csbnd H concentration decreases and new oxide features Cdbnd O and Osbnd Cdbnd O form, with the latter being a support for oxidation at the surface being a major reaction during discolouration. Results also show that irradiation with blue light during thermal ageing accelerates the kinetics of discolouration and the increased O1s/C1s ratio in XPS spectra.

  14. Specific LED-based red light photo-stimulation procedures improve overall sperm function and reproductive performance of boar ejaculates

    PubMed Central

    Yeste, Marc; Codony, Francesc; Estrada, Efrén; Lleonart, Miquel; Balasch, Sam; Peña, Alejandro; Bonet, Sergi; Rodríguez-Gil, Joan E.

    2016-01-01

    The present study evaluated the effects of exposing liquid-stored boar semen to different red light LED regimens on sperm quality and reproductive performance. Of all of the tested photo-stimulation procedures, the best pattern consisted of 10 min light, 10 min rest and 10 min of further light (10-10-10 pattern). This pattern induced an intense and transient increase in the majority of motility parameters, without modifying sperm viability and acrosome integrity. While incubating non-photo-stimulated sperm at 37 °C for 90 min decreased all sperm quality parameters, this reduction was prevented when the previously-described light procedure was applied. This effect was concomitant with an increase in the percentage of sperm with high mitochondrial membrane potential. When sperm were subjected to ‘in vitro’ capacitation, photo-stimulation also increased the percentage of sperm with capacitation-like changes in membrane structure. On the other hand, treating commercial semen doses intended for artificial insemination with the 10-10-10 photo-stimulation pattern significantly increased farrowing rates and the number of both total and live-born piglets for parturition. Therefore, our results indicate that a precise photo-stimulation procedure is able to increase the fertilising ability of boar sperm via a mechanism that could be related to mitochondrial function. PMID:26931070

  15. Study of high power white AC-LED based on the structure of composite bridge with SMD packaging

    NASA Astrophysics Data System (ADS)

    Wang, Zhibin; Gu, Yue; Xie, Shasha

    2010-10-01

    In this paper, a method of composite bridge structure packing with self-rectifier in the LED chips is introduced, based on the characteristics of PN junction of the high power LED. About dozens of low-power LED chips are pasted on the PCB boards which having good thermal conductivity in the form of bridge structure, regulating input voltage and current strength to make the LED chips at different bridge arms worked alternately by using of LED PN junction's own characteristics to achieve self-rectification. The copper cooling plates are sandwiched in the PCB boards to achieve for saving resource and improving brightness. During the work time, the LED flashes lights. Because of its feature of continuing light after power properties, the human eyes can not perceive the LED's flashing, their understanding on the light emitting is continuous.

  16. Inexpensive, pocket-sized LED-based fluorometer for undergraduate teaching laboratories and in-the-field chemical detection

    NASA Astrophysics Data System (ADS)

    Tiber, Gage; Basu, Partha; Corcovilos, Theodore A.

    2015-05-01

    Fluorometry is a standard experimental technique for the detection of chemical compounds in solution. Excitation light is absorbed by a sample and then longer-wavelength light is emitted. Typical laboratory fluorometers are large and expensive, making them poorly suited for field work and teaching laboratories. We present a simple battery-powered fluorometer built with off-the-shelf components and a 3D-printed body. The light sources are user-replaceable light emitting diodes (LEDs). Two independent light sources of different wavelengths allow ratiometric measurements of the sample. The detectors are photodiodes with interchangeable dielectric Fabry-Perot stack spectral filters. The light gathering optics are designed using non-imaging optics principles to maximize the amount of detected fluorescence light. We present the design of the device and demonstrate the sensitivity using a molecular detector of Pb2+ ions in solution. The absorption and emission wavelengths of the detector molecule change from 415 nm and 465 nm, resp., in the absence of Pb2+ to 389 nm and 423 nm, resp., in the presence of Pb2+. The estimated sensitivity of the fluorometer with this molecular detector is a few p.p.b.

  17. Assembling and Using an LED-Based Detector to Monitor Absorbance Changes during Acid-Base Titrations

    ERIC Educational Resources Information Center

    Santos, Willy G.; Cavalheiro, E´der T. G.

    2015-01-01

    A simple photometric assembly based in an LED as a light source and a photodiode as a detector is proposed in order to follow the absorbance changes as a function of the titrant volume added during the course of acid-base titrations in the presence of a suitable visual indicator. The simplicity and low cost of the electronic device allow the…

  18. A Light-Emitting Diode- (LED-) Based Absorption Sensor for Simultaneous Detection of Carbon Monoxide and Carbon Dioxide.

    PubMed

    Thurmond, Kyle; Loparo, Zachary; Partridge, William; Vasu, Subith S

    2016-06-01

    A sensor was developed for simultaneous measurements of carbon monoxide (CO) and carbon dioxide (CO2) fluctuations in internal combustion engine exhaust gases. This sensor utilizes low-cost and compact light-emitting diodes (LEDs) that emit in the 3-5 µm wavelength range. An affordable, fast response sensor that can measure these gases has a broad application that can lead to more efficient, fuel-flexible engines and regulation of harmful emissions. Light emission from LEDs is spectrally broader and more spatially divergent when compared to that of lasers, which presented many design challenges. Optical design studies addressed some of the non-ideal characteristics of the LED emissions. Measurements of CO and CO2 were conducted using their fundamental absorption bands centered at 4.7 µm and 4.3 µm, respectively, while a 3.6 µm reference LED was used to account for scattering losses (due to soot, window deposits, etc.) common to the three measurement LEDs. Instrument validation and calibration was performed using a laboratory flow cell and bottled-gas mixtures. The sensor was able to detect CO2 and CO concentration changes as small as 30 ppm and 400 ppm, respectively. Because of the many control and monitor species with infra-red absorption features, which can be measured using the strategy described, this work demonstrates proof of concept for a wider range of fast (250 Hz) and low-cost sensors for gas measurement and process monitoring. PMID:27091903

  19. Measurement of normalized spectral responsivity of digital imaging devices by using a LED-based tunable uniform source.

    PubMed

    Mahmoud, Khaled; Park, Seongchong; Park, Seung-Nam; Lee, Dong-Hoon

    2013-02-20

    We present an instrumentation solution for measurement of normalized spectral responsivity of digital imaging sensors and cameras. The instrument consists of multiple light-emitting diodes (LEDs), a single-grating monochromator, and a small-size integrating sphere. Wavelength tuning is achieved by a proper selection of LED in accordance with the monochromator setting in a range from 380 to 900 nm. High spectral purity with a bandwidth of 5 nm is realized without using double gratings and order-sorting filters. Experimental characteristics and calibration of the instrument are described with the related error and uncertainty sources. The performance is demonstrated by measuring a monochrome charge-coupled device and a trichromatic complementary metal-oxide-semiconductor device. The measurement uncertainty is evaluated to be less than 1% (k=2) except several wavelengths with low LED power. PMID:23434998

  20. LED-based Fourier transform spectroscopy of H218O in the 15,000-16,000 cm-1 range

    NASA Astrophysics Data System (ADS)

    Mikhailenko, S. N.; Serdyukov, V. I.; Sinitsa, L. N.

    2015-05-01

    The spectrum of Н218О has been recorded between 15,000 and 16,000 cm-1 by a Fourier transform spectrometer with spectral resolutions of 0.03 cm-1 and 0.05 cm-1 using high luminance LED light sources and a 60-cm multipath cell with a path length of 1920 and 3480 cm. A high signal-to-noise ratio (S/N=10,000) enabled us to register more than 1500 water vapor lines with intensities 1.0×10-27 to 2.2×10-24 cm/molecule at 296 K. 426 rotational-vibrational levels of the H218O molecule were assigned to eleven vibrational states: (014), (033), (052), (113), (132), (151), (212), (231), (311), (330) and (410). 72 Rotational-vibrational levels of the H217O molecule were assigned to six vibrational states: (014), (033), (113), (212), (311) and (410). An extended set of H218O transitions in the 15,000-16,000 cm-1 range was generated using the obtained energy level list and the results of a variational intensity calculation.

  1. Specific LED-based red light photo-stimulation procedures improve overall sperm function and reproductive performance of boar ejaculates.

    PubMed

    Yeste, Marc; Codony, Francesc; Estrada, Efrén; Lleonart, Miquel; Balasch, Sam; Peña, Alejandro; Bonet, Sergi; Rodríguez-Gil, Joan E

    2016-01-01

    The present study evaluated the effects of exposing liquid-stored boar semen to different red light LED regimens on sperm quality and reproductive performance. Of all of the tested photo-stimulation procedures, the best pattern consisted of 10 min light, 10 min rest and 10 min of further light (10-10-10 pattern). This pattern induced an intense and transient increase in the majority of motility parameters, without modifying sperm viability and acrosome integrity. While incubating non-photo-stimulated sperm at 37 °C for 90 min decreased all sperm quality parameters, this reduction was prevented when the previously-described light procedure was applied. This effect was concomitant with an increase in the percentage of sperm with high mitochondrial membrane potential. When sperm were subjected to 'in vitro' capacitation, photo-stimulation also increased the percentage of sperm with capacitation-like changes in membrane structure. On the other hand, treating commercial semen doses intended for artificial insemination with the 10-10-10 photo-stimulation pattern significantly increased farrowing rates and the number of both total and live-born piglets for parturition. Therefore, our results indicate that a precise photo-stimulation procedure is able to increase the fertilising ability of boar sperm via a mechanism that could be related to mitochondrial function. PMID:26931070

  2. Design and performance of a three-wavelength LED-based total scatter and backscatter integrating nephelometer

    NASA Astrophysics Data System (ADS)

    Müller, T.; Laborde, M.; Kassell, G.; Wiedensohler, A.

    2011-06-01

    Integrating nephelometers are instruments that directly measure a value close to the light scattering coefficient of airborne particles. Different models of nephelometers have been used for decades for monitoring and research applications. Now, a series of nephelometers (Ecotech models M9003, Aurora 1000 and Aurora 3000) with newly designed light sources based on light emitting diodes are available. This article reports on the design of these integrating nephelometers and a comparison of the Aurora 3000 to another commercial instrument (TSI model 3563) that uses an incandescent lamp. Both instruments are three-wavelength, total and backscatter integrating nephelometers. We present a characterization of the new light source design of the Aurora 3000 and provide parameterizations for its angular sensitivity functions. These parameterizations facilitate to correct for measurement artefacts using Mie-theory. Furthermore, correction factors are provided as a function of the Ångström exponent. Comparison measurements against the TSI 3563 with laboratory generated white particles and ambient air are also shown and discussed. Both instruments agree well within the calibration uncertainties and detection limit for total scattering with differences less than 5 %. Differences for backscattering are higher by up to 11 %. Highest differences were found for the longest wavelengths, where the signal to noise ratio is lowest. Differences at the blue and green wavelengths are less than 4 % and 3 %, respectively, for both total and backscattering.

  3. Design and performance of a three-wavelength LED-based total scatter and backscatter integrating nephelometer

    NASA Astrophysics Data System (ADS)

    Müller, T.; Laborde, M.; Kassell, G.; Wiedensohler, A.

    2010-11-01

    Integrating nephelometers are instruments that directly measure a value close to the light scattering coefficient of airborne particles. Different models of nephelometers have been used for decades for monitoring and research applications. Now, a series of nephelometers (Ecotech models M9003, Aurora 1000 and Aurora 3000) with newly designed light sources based on light emitting diodes are available. This article reports on the design of these integrating nephelometers and a comparison of the Aurora 3000 to another commercial instrument (TSI model 3563) that uses an incandescent lamp. Both instruments are three-wavelength, total and backscatter integrating nephelometers. We present a characterization of the new light source design of the Aurora 3000 and provide parameterizations for its angular sensitivity functions. These parameterizations facilitate to correct for measurement artefacts using Mie-theory. Comparison measurements against the TSI 3563 with laboratory generated white particles and ambient air are shown and discussed. Both instruments agree well within the calibration uncertainties and detection limit for total scattering with differences less than 5%. Differences for backscattering are higher by up to 11%. Highest differences were found for the longest wavelengths, where the signal to noise ratio is lowest. Differences at the blue and green wavelengths are less than 4% and 3%, respectively, for both total and backscattering.

  4. Light-emitting diode-based multiwavelength diffuse optical tomography system guided by ultrasound.

    PubMed

    Yuan, Guangqian; Alqasemi, Umar; Chen, Aaron; Yang, Yi; Zhu, Quing

    2014-12-01

    Laser diodes are widely used in diffuse optical tomography (DOT) systems but are typically expensive and fragile, while light-emitting diodes (LEDs) are cheaper and are also available in the near-infrared (NIR) range with adequate output power for imaging deeply seated targets. In this study, we introduce a new low-cost DOT system using LEDs of four wavelengths in the NIR spectrum as light sources. The LEDs were modulated at 20 kHz to avoid ambient light. The LEDs were distributed on a hand-held probe and a printed circuit board was mounted at the back of the probe to separately provide switching and driving current to each LED. Ten optical fibers were used to couple the reflected light to 10 parallel photomultiplier tube detectors. A commercial ultrasound system provided simultaneous images of target location and size to guide the image reconstruction. A frequency-domain (FD) laser-diode-based system with ultrasound guidance was also used to compare the results obtained from those of the LED-based system. Results of absorbers embedded in intralipid and inhomogeneous tissue phantoms have demonstrated that the LED-based system provides a comparable quantification accuracy of targets to the FD system and has the potential to image deep targets such as breast lesions. PMID:25473884

  5. Light-emitting diode-based multiwavelength diffuse optical tomography system guided by ultrasound

    PubMed Central

    Yuan, Guangqian; Alqasemi, Umar; Chen, Aaron; Yang, Yi; Zhu, Quing

    2014-01-01

    Abstract. Laser diodes are widely used in diffuse optical tomography (DOT) systems but are typically expensive and fragile, while light-emitting diodes (LEDs) are cheaper and are also available in the near-infrared (NIR) range with adequate output power for imaging deeply seated targets. In this study, we introduce a new low-cost DOT system using LEDs of four wavelengths in the NIR spectrum as light sources. The LEDs were modulated at 20 kHz to avoid ambient light. The LEDs were distributed on a hand-held probe and a printed circuit board was mounted at the back of the probe to separately provide switching and driving current to each LED. Ten optical fibers were used to couple the reflected light to 10 parallel photomultiplier tube detectors. A commercial ultrasound system provided simultaneous images of target location and size to guide the image reconstruction. A frequency-domain (FD) laser-diode-based system with ultrasound guidance was also used to compare the results obtained from those of the LED-based system. Results of absorbers embedded in intralipid and inhomogeneous tissue phantoms have demonstrated that the LED-based system provides a comparable quantification accuracy of targets to the FD system and has the potential to image deep targets such as breast lesions. PMID:25473884

  6. UV-LED exposure system for low-cost photolithography

    NASA Astrophysics Data System (ADS)

    Yapici, Murat Kaya; Farhat, Ilyas

    2014-03-01

    This paper reports the development of a low-cost, portable, light-emitting diode (LED)-based UV exposure system for photolithography. The major system components include UV-LEDs, microcontroller, digital-to-analog (D/A) converter and LED control circuitry. The UV-LED lithography system is also equipped with a digital user interface (LCD and keypad) and permits accurate electronic control on the exposure time and power. Hence the exposure dose can be varied depending on process requirements. Compared to traditional contact lithography, the UV-LED lithography system is significantly cheaper, simple to construct using off-the shelf components and does not require complex infrastructure to operate. Such reduction in system cost and complexity renders UV-LED lithography as a perfect candidate for micro lithography with large process windows typically suitable for MEMS, microfluidics applications.

  7. Design of new collection systems for multi LED light engines

    NASA Astrophysics Data System (ADS)

    Murat, Hüseyin; Cuypers, Dieter; De Smet, Herbert

    2006-04-01

    LED based projectors have numerous advantages compared to traditional projectors: they are more compact, exhibit a larger color gamut and a longer lifetime, the supply voltage is lower, the absence of ultra violet, infrared radiation and mercury vapour, etc. Furthermore LED's can switch on and off very rapidly (possibility to pulse them) and they have a high dimming ratio that can be used to improve the contrast. However, there is also an important disadvantage: the optical power per unit of etendue (luminance) of an LED is significantly lower than that of e.g. an UHP-lamp. Because of this and the etendue limitation of the projector (small light valve, f-number projection lens), the projected flux on the screen will not be high. Despite this shortcoming, LED's are still very interesting for low power applications because of their superior properties. However we have to collect the available light flux optimally and combine multiple LED's with high luminance within the available system etendue. In this paper we have studied collection optics that collect the LED flux with high optical efficiency and collimation and reshape the spot in a uniform illuminated rectangle with the sizes of the micro display. We have designed 'Gradually Tapered Light Pipes', 'Elliptical Reflectors' and 'Parabolic Reflectors'. Furthermore we have combined many of these LED/collector combinations to get a high luminance illumination engine for LED based projectors.

  8. Camera system for multispectral imaging of documents

    NASA Astrophysics Data System (ADS)

    Christens-Barry, William A.; Boydston, Kenneth; France, Fenella G.; Knox, Keith T.; Easton, Roger L., Jr.; Toth, Michael B.

    2009-02-01

    A spectral imaging system comprising a 39-Mpixel monochrome camera, LED-based narrowband illumination, and acquisition/control software has been designed for investigations of cultural heritage objects. Notable attributes of this system, referred to as EurekaVision, include: streamlined workflow, flexibility, provision of well-structured data and metadata for downstream processing, and illumination that is safer for the artifacts. The system design builds upon experience gained while imaging the Archimedes Palimpsest and has been used in studies of a number of important objects in the LOC collection. This paper describes practical issues that were considered by EurekaVision to address key research questions for the study of fragile and unique cultural objects over a range of spectral bands. The system is intended to capture important digital records for access by researchers, professionals, and the public. The system was first used for spectral imaging of the 1507 world map by Martin Waldseemueller, the first printed map to reference "America." It was also used to image sections of the Carta Marina 1516 map by the same cartographer for comparative purposes. An updated version of the system is now being utilized by the Preservation Research and Testing Division of the Library of Congress.

  9. Visible and infrared multispectral illumination concept based on Galilean collimation systems: IACATS illumination source

    NASA Astrophysics Data System (ADS)

    Ramos Zapata, Gonzalo; Belenguer Dávila, Tomás; Pastor Santos, Carmen; Restrepo Gómez, René; González Alvarado, Concepción; Laguna Hernández, Hugo; Astolfi Carbonell, Antonio; Moreno Raso, Javier; Argelaguet, Heribert; Serrano, Javier

    2010-07-01

    A LED based illumination system in which five Galilean collimation systems have been used is reported on. It is part of a turbulence simulator for the evaluation of on ground telescopes instrumentation developed by INTA (optics) and LIDAX (opto-mechanics) for the IAC called IACATS. The illumination requirements (some visible and infrared lines) allow the use of five different LEDs (red, green, blue and two infrareds). In order to optimize the illumination level of each wavelength, a Galilean collimating optical configuration was constructed for each wavelength channel. The IACATS instrument simulates a scene consisting of a set of different binary stars simulating the required angular separation between them, ant their spectral characteristics. As a result, a visible and infrared multi-spectral illumination system has been integrated as a part of the turbulence simulator, and the features (opto-mechanical) and illumination characteristics are described in the following lines.

  10. A calibration system for Compton polarimetry at e+e- linear colliders

    NASA Astrophysics Data System (ADS)

    Vormwald, B.; List, J.; Vauth, A.

    2016-01-01

    Polarimetry with permille-level precision is essential for future electron-positron linear colliders. Compton polarimeters can reach negligible statistical uncertainties within seconds of measurement time. The dominating systematic uncertainties originate from the response and alignment of the detector which records the Compton scattered electrons. The robust baseline technology for the Compton polarimeters foreseen at future linear colliders is based on an array of gas Cherenkov detectors read out by photomultipliers. In this paper, we will present a calibration method which promises to monitor nonlinearities in the response of such a detector at the level of a few permille. This method has been implemented in an LED-based calibration system which matches the existing prototype detector. The performance of this calibration system is sufficient to control the corresponding contribution to the total uncertainty on the extracted polarisation to better than 0.1%.

  11. Novel approach to characterize and compare the performance of night vision systems in representative illumination conditions

    NASA Astrophysics Data System (ADS)

    Roy, Nathalie; Vallières, Alexandre; St-Germain, Daniel; Potvin, Simon; Dupuis, Michel; Bouchard, Jean-Claude; Villemaire, André; Bérubé, Martin; Breton, Mélanie; Gagné, Guillaume

    2016-05-01

    A novel approach is used to characterize and compare the performance of night vision systems in conditions more representative of night operation in terms of spectral content. Its main advantage compared to standard testing methodologies is that it provides a fast and efficient way for untrained observers to compare night vision system performances with realistic illumination spectra. The testing methodology relies on a custom tumbling-E target and on a new LED-based illumination source that better emulates night sky spectral irradiances from deep overcast starlight to quarter-moon conditions. In this paper, we describe the setup and we demonstrate that the novel approach can be an efficient method to characterize among others night vision goggles (NVG) performances with a small error on the photogenerated electrons compared to the STANAG 4351 procedure.

  12. A compact signal transmitter for UV communication system

    NASA Astrophysics Data System (ADS)

    Wang, Rongyang; Yuan, Yonggang; Li, Chao; Zhang, Yan; Li, Xiangyang

    2011-02-01

    Three LED-based signal transmitting schemes were presented to build the transmitter of UV communication system. Microprogrammed Control Unit (MCU) was taken to generate digital driving signal and to accomplish modulation with Keil C51 development tool. The modulated signal with a certain pulse width was sent to a LED driving circuit. High power 365nm UV LED was adopted according to the trade-off between its scattering coefficient and price. Utilization of high power UV LED improved the integration density of printed circuit board (PCB), which was beneficial to assemble a beam shaping system. The whole transmitter was installed on a four-dimensional optical stage for system adjustments and measurements. The radiant optical power of UV LED was measured. Some issues about the PCB design were also discussed. The MCU output waveforms were demonstrated on an oscilloscope and the UV LED output optical pulse were verified by a Hamamatsu APD module. Different modulation data rates were investigated. Experimental result showed that this signal transmitter for UV communication system could transmit optical signal well and greatly shorten the system development cycle.

  13. Novel inorganic borate host phosphor K2Al2B2O7:Dy3+ for LED based solid state lighting

    NASA Astrophysics Data System (ADS)

    Palaspagar, R. S.; Sonekar, R. P.; Omanwar, S. K.

    2013-06-01

    In the present work we report the preparation and photoluminescence characteristics of Dy3+ doped borate phosphor K2Al2B2O7:Dy3+. The fine polycrystalline powder samples of K2Al2B2O7:Dy3+ has been prepared by a novel combustion technique. This method is based on the exothermic redox reaction involves, metal nitrates and organic fuel (urea). The formation of samples was confirmed by powder XRD technique. The photoluminescence properties of borate phosphors have been investigated on fluorescence spectrometer (F-7000). The PL excitation spectra of K2Al2B2O7:Dy3+ consists of several bands peaking at 241 nm, 297 nm, 324 nm, 350 nm, 364 nm and 387 nm. Since the prominent excitation peaks are above 360nm, the phosphor may useful for solid state lighting application. The emission spectrum monitored at 351 nm excitation consists of blue emission band peaking at 481 nm and yellow emission band peaking at 574nm.

  14. Light extraction efficiency enhancement of GaN-based blue LEDs based on ITO/ InxO ohmic contacts with microstructure formed by annealing in oxygen.

    PubMed

    Luo, Yi; Bai, Yiming; Han, Yanjun; Li, Hongtao; Wang, Lai; Wang, Jian; Sun, Changzheng; Hao, Zhibiao; Xiong, Bing

    2016-05-16

    Indium tin oxide (ITO)/ indium oxide (InxO) double layer structure was adopted as the transparent conduction and light scattering function layer to improve the light extraction efficiency of the GaN-based blue LEDs. The double layer structure was first deposited in one run by electron beam evaporation using ITO and Indium as the source respectively, and then annealed in an oxygen environment. This method can fabricate transparent electrode with microstructure and low specific contact resistivity one time free from lithography and etching, which makes the fabrication process simple and at a ower cost. For the 220 nm ITO/ 170 nm InxO double layer sample annealed at 600°C for 15 min in oxygen, measurement results show that its root mean square of roughness of the surface microstructure can be as high as 85.2 nm which introduces the strongest light scattering. Its light transmittance at 450 nm can maintain 92.4%. At the same time, it can realize lower specific contact resistivity with p-InGaN. Compared with the GaN-based blue LEDs with only 220 nm ITO electrode, the light output power of the LEDs with 220 nm ITO/ 170 nm InxO double layer structure can be increased about 58.8%, and working voltage at 20 mA injection current is decreased about 0.23 V due to the enhanced current spreading capability. The light output power improvement is also theoretically convinced by finite difference time domain simulations. PMID:27409953

  15. High-output LED based on p-n Al(x)Ga(1-x)As(Si) structures of varying composition

    NASA Astrophysics Data System (ADS)

    Bednarskii, V. V.; Gaft, A. E.; Kovalenko, V. F.; Lisovenko, V. D.; Litvin, A. A.

    Factors affecting the emission output of p-n GaAs(Si) structures are investigated. It is found that increasing the p-layer thickness, doping with isovalent indium impurity, and decreasing the GaAs substrate thickness and electron concentration result in increased emission intensity. It is demonstrated that a further increase in the emission power of p-n Al(x)Ga(1-x)As(Si, In) structures (up to 7-8 mW) for a LED current of 100 mA) can be achieved by creating a surface microrelief and applying an antireflection anodic oxide coating to the mesa structures.

  16. LED-Based Fourier Transform Spectroscopy: the HD16O Absorption Spectrum in the Range of 11200-12400 cm-1

    NASA Astrophysics Data System (ADS)

    Sinitsa, L. N.; Serdyukov, V. I.; Polovtseva, E. R.; Shcherbakov, A. P.; Voronin, B. A.; Bykov, A. D.

    2016-03-01

    The vibrational—rotational spectrum of the HD16O molecule is studied within the range of 11200-12400 cm-1. The spectrum is recorded by an IFS-125M Fourier spectrometer with a resolution of 0.05 cm-1. The measurements are performed using a multipass White cell. A light-emitting diode is used as a radiation source. The signal-to-noise ratio was about 104. The centers, intensities, and half-widths of the spectral lines are determined by fitting to the experimental data by the least-squares method. A linelist containing more than 1500 lines is created. The results obtained are compared with the experimental data of other authors.

  17. White LED based on CaAl2Si2O8:Eu2+ Mn2+ phosphor and CdS/ZnS quantum dots

    NASA Astrophysics Data System (ADS)

    Shen, Changyu; Zhong, Chuan; Hou, Qianglong; Li, Ke

    2011-02-01

    Core/shell CdS/ZnS quantum dots (QDs) with the emission wavelength of 610nm, was synthesized by thermal deposition using cadmium oxide and selenium as precursors in a hot lauric acid and hexadecylamine trioctylphosphine oxide hybrid. CaAl2Si2O8:Eu2+ Mn2+ phosphor was synthesized by high-temperature solid state reaction at 1290 °C for 2 hours under the H2 reducing atmosphere, and X-ray powder diffraction analysis confirmed the formation of it. It has two emission bands peaking at 420 nm and 580nm originated from the transition 5d to 4f of Eu2+ and 4T1-6A1 of Mn2+, respectively. Blends of CaAl2Si2O8:Eu2+,Mn2+ phosphor and CdS/ZnS QDs exhibited the prominent spectral evolution with an increasing content of QDs. A hybrid white LED, which combines a blue LED with the blend of CaAl2Si2O8:Eu2+ Mn2+ phosphor and QDs with a weight ratio of 2:1, with the CIE coordinate of (0.3183, 0.3036) and CRI of 85 was obtained.

  18. On the application of CaF2:Eu and SrF2:Eu phosphors in LED based phototherapy lamp

    NASA Astrophysics Data System (ADS)

    Belsare, P. D.; Moharil, S. V.; Joshi, C. P.; Omanwar, S. K.

    2013-06-01

    In the last few years the interest of scientific community has been increased towards solid state lighting based on LEDs because of their superior advantages over the conventional fluorescent lamps. As the GaN based LEDs are easily available efforts of the researchers are now on making the new phosphors which are excitable in the near UV region (360-400nm) for solid state lighting. This paper reports the photoluminescence characteristics of CaF2:Eu and SrF2:Eu phosphor prepared by wet chemical method. The violet emission of these phosphors with near UV excitation can be useful in making a phototherapy lamp based on LEDs for treating various skin diseases like acne vulgaris and hyperbilirubinemia.

  19. Development of a new airborne humidigraph system.

    SciTech Connect

    Pekour, Mikhail S.; Schmid, Beat; Chand, Duli; Hubbe, John M.; Kluzek, Celine D.; Nelson, Danny A.; Tomlinson, Jason M.; Cziczo, Daniel J.

    2012-12-06

    Modeling and measurements of aerosol properties is complicated by the hygroscopic behavior of the aerosols adding significant uncertainty to our best estimates of the direct effect aerosols exert on the radiative balance of the atmosphere. Airborne measurements of aerosol hygroscopicity are particularly challenging but critically needed. This motivated the development of a newly designed system which can measure the dependence of the aerosol light scattering coefficient (σsp) on relative humidity (RH), known as f(RH), in real-time at a rapid rate (<10 s) on an aerial platform. The new system has several advantages over existing systems. It consists of three integrating nephelometers and humidity conditioners for simultaneous measurement of the σsp at three different RHs. The humidity is directly controlled in exchanger cells without significant temperature disturbances and without particle dilution, heating or loss of volatile compounds. The single-wavelength nephelometers are illuminated by LED-based light sources thereby minimizing heating of the sample stream. The flexible design of the RH conditioners, consisting of a number of specially designed exchanger cells (driers or humidifiers), enables us to measure f(RH) under hydration or dehydration conditions (always starting with the aerosol in a known state) with a simple system re-configuration. These exchanger cells have been characterized for losses of particles using latex spheres and laboratory generated ammonium sulfate aerosols. Residence times of 6 - 9 s in the exchangers and subsequent lines is sufficient for most aerosols to attain equilibrium with the new water vapor content. The performance of this system has been assessed aboard DOE’s G-1 research aircraft during test flights over California, Oregon, and Washington.

  20. An Efficient LED System-in-Module for General Lighting Applications

    SciTech Connect

    2008-09-14

    The objective of the project was to realize an LED-based lighting technology platform for general illumination, starting with LED chips, and integrating the necessary technologies to make compact, user-friendly, high-efficiency, energy-saving sources of controlled white (or variable-colored) light. The project is to build the system around the LEDs, and not to work on the LEDs themselves, in order that working products can be introduced soon after the LEDs reach suitable efficiency for mass-production of high-power light sources for general illumination. Because the light sources are intended for general illumination, color must be accurately maintained, requiring feedback control in the electronics. The project objective has been realized and screw base demonstrators, based on the technology developed in the project, have been built.

  1. System requirements. [Space systems

    SciTech Connect

    Austin, R.E.

    1982-06-01

    Requirements of future space systems, including large space systems, that operate beyond the space shuttle are discussed. Typical functions required of propulsion systems in this operational regime include payload placement, retrieval, observation, servicing, space debris control and support to large space systems. These functional requirements are discussed in conjunction with two classes of propulsion systems: (1) primary or orbit transfer vehicle (OTV) and (2) secondary or systems that generally operate within or relatively near an operational base orbit. Three propulsion system types are described in relation to these requirements: cryogenic OTV, teleoperator maneuvering system and a solar electric OTV.

  2. Solar system positioning system

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin I.; Chui, Talso

    2006-01-01

    Power-rich spacecraft envisioned in Prometheus initiative open up possibilities for long-range high-rate communication. A constellation of spacecraft on orbits several A.U. from the Sun, equipped with laser transponders and precise clocks can be configured to measure their mutual distances to within few cm. High on-board power can create substantial non-inertial contribution to the spacecraft trajectory. We propose to alleviate this contribution by employing secondary ranging to a passive daughter spacecraft. Such constellation can form the basis of it navigation system capable of providing position information anywhere in the soIar system with similar accuracy. Apart from obvious Solar System exploration implications, this system can provide robust reference for GPS and its successors.

  3. Systems autonomy

    NASA Technical Reports Server (NTRS)

    Lum, Henry, Jr.

    1988-01-01

    Information on systems autonomy is given in viewgraph form. Information is given on space systems integration, intelligent autonomous systems, automated systems for in-flight mission operations, the Systems Autonomy Demonstration Project on the Space Station Thermal Control System, the architecture of an autonomous intelligent system, artificial intelligence research issues, machine learning, and real-time image processing.

  4. Experimental investigation of analog and digital dimming techniques on photometric performance of an indoor Visible Light Communication (VLC) system

    NASA Astrophysics Data System (ADS)

    Zafar, Fahad; Kalavally, Vineetha; Bakaul, Masuduzzaman; Parthiban, R.

    2015-09-01

    For making commercial implementation of light emitting diode (LED) based visible light communication (VLC) systems feasible, it is necessary to incorporate it with dimming schemes which will provide energy savings, moods and increase the aesthetic value of the places using this technology. There are two general methods which are used to dim LEDs commonly categorized as analog and digital dimming. Incorporating fast data transmission with these techniques is a key challenge in VLC. In this paper, digital and analog dimming for a 10 Mb/s non return to zero on-off keying (NRZ-OOK) based VLC system is experimentally investigated considering both photometric and communicative parameters. A spectrophotometer was used for photometric analysis and a line of sight (LOS) configuration in the presence of ambient light was used for analyzing communication parameters. Based on the experimental results, it was determined that digital dimming scheme is preferable for use in indoor VLC systems requiring high dimming precision and data transmission at lower brightness levels. On the other hand, analog dimming scheme is a cost effective solution for high speed systems where dimming precision is insignificant.

  5. Immune System

    MedlinePlus

    ... How Can I Help a Friend Who Cuts? Immune System KidsHealth > For Teens > Immune System Print A A ... could put us out of commission. What the Immune System Does The immune (pronounced: ih-MYOON) system, which ...

  6. 49 CFR 392.22 - Emergency signals; stopped commercial motor vehicles.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...; stopped commercial motor vehicles. (a) Hazard warning signal flashers. Whenever a commercial motor vehicle... than necessary traffic stops, the driver of the stopped commercial motor vehicle shall immediately activate the vehicular hazard warning signal flashers and continue the flashing until the driver places...

  7. 49 CFR 392.22 - Emergency signals; stopped commercial motor vehicles.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...; stopped commercial motor vehicles. (a) Hazard warning signal flashers. Whenever a commercial motor vehicle... than necessary traffic stops, the driver of the stopped commercial motor vehicle shall immediately activate the vehicular hazard warning signal flashers and continue the flashing until the driver places...

  8. 49 CFR 392.22 - Emergency signals; stopped commercial motor vehicles.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...; stopped commercial motor vehicles. (a) Hazard warning signal flashers. Whenever a commercial motor vehicle... than necessary traffic stops, the driver of the stopped commercial motor vehicle shall immediately activate the vehicular hazard warning signal flashers and continue the flashing until the driver places...

  9. The Effectiveness of School Signs with Flashing Beacons in Reducing Vehicle Speeds. Research Report No. 429.

    ERIC Educational Resources Information Center

    Zegeer, Charles V.

    A detailed study of warning signs with flashers in school zones was conducted by the Kentucky Department of Transportation to determine the signs' effectiveness in reducing the speeds of vehicles during times of pedestrian activity. Field investigations were conducted at all of the 120 flasher locations in Kentucky Highway Districts 6, 7, and 9.…

  10. Design and optimization of a light-emitting diode projection micro-stereolithography three-dimensional manufacturing system.

    PubMed

    Zheng, Xiaoyu; Deotte, Joshua; Alonso, Matthew P; Farquar, George R; Weisgraber, Todd H; Gemberling, Steven; Lee, Howon; Fang, Nicholas; Spadaccini, Christopher M

    2012-12-01

    The rapid manufacture of complex three-dimensional micro-scale components has eluded researchers for decades. Several additive manufacturing options have been limited by either speed or the ability to fabricate true three-dimensional structures. Projection micro-stereolithography (PμSL) is a low cost, high throughput additive fabrication technique capable of generating three-dimensional microstructures in a bottom-up, layer by layer fashion. The PμSL system is reliable and capable of manufacturing a variety of highly complex, three-dimensional structures from micro- to meso-scales with micro-scale architecture and submicron precision. Our PμSL system utilizes a reconfigurable digital mask and a 395 nm light-emitting diode (LED) array to polymerize a liquid monomer in a layer-by-layer manufacturing process. This paper discusses the critical process parameters that influence polymerization depth and structure quality. Experimental characterization and performance of the LED-based PμSL system for fabricating highly complex three-dimensional structures for a large range of applications is presented. PMID:23278017

  11. Systems Thinking (and Systems Doing).

    ERIC Educational Resources Information Center

    Brethower, Dale M.; Dams, Peter-Cornelius

    1999-01-01

    Introduces human performance technology (HPT) by answering the following questions related to: what systems does; practical issues and questions to which systems thinking is relevant; research questions and answers with respect to systems thinking; how HPT practitioners can do systems thinking; systems thinking tools; what is and is not known…

  12. Optical fluence modelling for ultraviolet light emitting diode-based water treatment systems.

    PubMed

    Simons, R; Gabbai, U E; Moram, M A

    2014-12-01

    This work presents a validated optical fluence rate model optimised for ultraviolet light-emitting diodes (UV-LEDs), which allow a very wide range of emission wavelengths and source geometries to be used in water treatment units. The model is based on a Monte Carlo approach, in which an incremental ray-tracing algorithm is used to calculate the local volumetric rate of energy absorption and subsequently convert it to the local fluence rate distribution for an UV-LED water treatment chamber of arbitrary design. The model includes contributions from optical reflections and scattering by treatment chamber walls and from scattering due to particulates and/or microorganisms. The model successfully predicts optical fluence rates in point-of-use water treatment units, as verified using biodosimetry with MS-2 bacteriophage at a UV-LED emission wavelength of 254 nm. The effects of chamber geometry are also modelled effectively and are consistent with the inactivation data for E. coli at 254 nm. The data indicate that this model is suitable for application in the design and optimisation of UV-LED-based water treatment systems. PMID:25222335

  13. The video fluorescent device for diagnostics of cancer of human reproductive system

    NASA Astrophysics Data System (ADS)

    Brysin, Nickolay N.; Linkov, Kirill G.; Stratonnikov, Alexander A.; Savelieva, Tatiana A.; Loschenov, Victor B.

    2008-06-01

    Photodynamic therapy (PDT) is one of the advanced methods of treatment of skin cancer and surfaces of internal organs. The basic advantages of PDT are high efficiency and low cost of treatment. PDT technique is needed for providing fluorescent diagnostics. Laser-based systems are widely applied to the fluorescence excitations for diagnostic because of a narrow spectrum of fluorescence excitation and high density of radiation. Application of laser systems for carrying out fluorescent diagnostics gives the image of a tumor distorted by speckles that does not give an opportunity to obtain full information about the form of a tumor quickly. Besides, these laser excitation systems have complicated structure and high cost. As a base for the development and creation of a video fluorescent device one of commercially produced colposcopes was chosen. It allows to decrease cost of the device, and also has enabled to make modernization for already used colposcopes. A LED-based light source was offered to be used for fluorescence excitation in this work. The maximum in a spectrum of radiation of LEDs corresponds to the general spectral maximum of protoporphyrin IX (PPIX) absorption. Irradiance in the center of a light spot is 31 mW/cm2. The receiving optical system of the fluorescent channel is adjusted at 635 nm where a general spectral maximum of fluorescence PPIX is located. Also the device contains a RGB video channel, a white light source and a USB spectrometer LESA-01-BIOSPEC, for measurement of spectra of fluorescence and diffusion reflections in treatment area. The software is developed for maintenance of the device. Some studies on laboratory animals were made. As a result, areas with the increased concentration of a PPIX were correctly detected. At present, the device is used for diagnostics of cancer of female reproductive system in Research Centre for Obstetrics, Gynecology and Perinatology of the Russian Academy of Medical Sciences (Moscow, Russia).

  14. Instrumentation and automated photometric titration procedure for total acidity determination in red wine employing a multicommuted flow system.

    PubMed

    Garcia, Ausberta Jesus Cabezas; Reis, Boaventura F

    2006-01-01

    An automated procedure for photometric titration of red wine and associated instrumentation is described. The procedure was based on the flow-batch approach implemented employing multicommutation. The photometric detection was carried out using a homemade LED-based photometer. The mixing device, LED, and photodetector were attached to the titration chamber in order to form a compact and small-sized unit. The flow system comprised an automatic injector and three-way solenoid valves, which were controlled by a microcomputer through an electronic interface card. The software, written in Quick BASIC 4.5, was designed with abilities to accomplish all steps of the titration procedure including data acquisition and real-time processing to decide about the course of titration in the following step and so forth, until the titration endpoint was reached. The usefulness of the proposed titration system was demonstrated by analyzing red wine samples. When results were compared with those obtained using the AOAC reference method, no significant difference was observed at the 95% confidence level. A relative standard deviation of ca 2% (n=9) was obtained when processing a typical red wine sample containing 7.3 gl-1 total acidity expressed as tartaric acid. PMID:17671625

  15. Instrumentation and Automated Photometric Titration Procedure for Total Acidity Determination in Red Wine Employing a Multicommuted Flow System

    PubMed Central

    Garcia, Ausberta Jesus Cabezas; Reis, Boaventura F.

    2006-01-01

    An automated procedure for photometric titration of red wine and associated instrumentation is described. The procedure was based on the flow-batch approach implemented employing multicommutation. The photometric detection was carried out using a homemade LED-based photometer. The mixing device, LED, and photodetector were attached to the titration chamber in order to form a compact and small-sized unit. The flow system comprised an automatic injector and three-way solenoid valves, which were controlled by a microcomputer through an electronic interface card. The software, written in Quick BASIC 4.5, was designed with abilities to accomplish all steps of the titration procedure including data acquisition and real-time processing to decide about the course of titration in the following step and so forth, until the titration endpoint was reached. The usefulness of the proposed titration system was demonstrated by analyzing red wine samples. When results were compared with those obtained using the AOAC reference method, no significant difference was observed at the 95% confidence level. A relative standard deviation of ca  2% (n=9 ) was obtained when processing a typical red wine sample containing 7.3 gl -1 total acidity expressed as tartaric acid. PMID:17671625

  16. Energy calibration of a multilayer photon detector

    SciTech Connect

    Johnson, R.A.

    1983-01-01

    The job of energy calibration was broken into three parts: gain normalization of all equivalent elements; determination of the functions for conversion of pulse height to energy; and gain stabilization. It is found that calorimeter experiments are no better than their calibration systems - calibration errors will be the major source of error at high energies. Redundance is found to be necessary - the system should be designed such that every element could be replaced during the life of the experiment. It is found to be important to have enough data taken during calibration runs and during the experiment to be able to sort out where the calibration problems were after the experiment is over. Each layer was normalized independently with electrons, and then the pulse height to energy conversion was determined with photons. The primary method of gain stabilization used the light flasher system. (LEW)

  17. Discovery Systems

    NASA Technical Reports Server (NTRS)

    Pell, Barney

    2003-01-01

    A viewgraph presentation on NASA's Discovery Systems Project is given. The topics of discussion include: 1) NASA's Computing Information and Communications Technology Program; 2) Discovery Systems Program; and 3) Ideas for Information Integration Using the Web.

  18. Crystal Systems.

    ERIC Educational Resources Information Center

    Schomaker, Verner; Lingafelter, E. C.

    1985-01-01

    Discusses characteristics of crystal systems, comparing (in table format) crystal systems with lattice types, number of restrictions, nature of the restrictions, and other lattices that can accidently show the same metrical symmetry. (JN)

  19. Concentrator Systems

    NASA Astrophysics Data System (ADS)

    Luque-Heredia, Ignacio; Luque, Antonio

    2015-10-01

    The following sections are included: * Introduction * The early development of CPV * Concentrator solar cells * Optics for photovoltaic concentrators * Photovoltaic concentration modules * Tracking systems for photovoltaic concentration * High-concentration systems * Rating and performance * Cost considerations * Conclusions * References

  20. Fluid Management System (FMS) fluid systems overview

    NASA Technical Reports Server (NTRS)

    Baird, R. S.

    1990-01-01

    Viewgraphs on fluid management system (FMS) fluid systems overview are presented. Topics addressed include: fluid management system description including system requirements (integrated nitrogen system, integrated water system, and integrated waste gas system) and physical description; and fluid management system evolution.

  1. Systems Engineering

    NASA Technical Reports Server (NTRS)

    Pellerano, Fernando

    2015-01-01

    This short course provides information on what systems engineering is and how the systems engineer guides requirements, interfaces with the discipline leads, and resolves technical issues. There are many system-wide issues that either impact or are impacted by the thermal subsystem. This course will introduce these issues and illustrate them with real life examples.

  2. Linked Systems.

    ERIC Educational Resources Information Center

    Association of Research Libraries, Washington, DC.

    Three papers are compiled here for research library directors: (1) "Background: Open Systems Interconnection," in which David F. Bishop provides fundamental background information to explain the concept of the emerging technology of linked systems and open systems interconnection--i.e., an agreed upon standard set of conventions or rules that,…

  3. LED-based Fourier transform spectroscopy of 16O12C18O and 12C18O2 in the 11,260-11,430 cm-1 range

    NASA Astrophysics Data System (ADS)

    Serdyukov, V. I.; Sinitsa, L. N.; Lugovskoi, A. A.; Borkov, Yu. G.; Tashkun, S. A.; Perevalov, V. I.

    2016-07-01

    The absorption spectrum of the 16O12C18O and 12C18O2 carbon dioxide isotopologues has been recorded in the 11,260- 11,430 cm-1 spectral range using Bruker IFS 125 HR Fourier transform spectrometer with resolution 0.05 cm-1 at temperature 297 K and path length 24 m. The 18O enriched sample of carbon dioxide at total pressure 96.5 mbar was used for these purposes. The spectrometer used LED emitter as a light source. This gave possibility to reach the minimal detectable absorption coefficient αmin~1.4×10-7 cm-1 using 23,328 scans. In the recorded spectrum we have assigned the 00051-00001 band for both 16O12C18O and 12C18O2 isotopologues using the predictions performed within the framework of the method of effective operators. The line positions and intensities of the observed bands are found. The comparison of the observed and predicted line positions and intensities is performed confirming good accuracy of the predictions. The spectroscopic parameters for the observed bands are determined.

  4. High color rendering index white LED based on nano-YAG:Ce3+ phosphor hybrid with CdSe/CdS/ZnS core/shell/shell quantum dots

    NASA Astrophysics Data System (ADS)

    Shen, Changyu; Chu, Jinlei; Qian, Feng; Zou, Xin; Zhong, Chuan; Li, Ke; Jin, Shangzhong

    2012-08-01

    To improve the poor color rendering index (CRI) of YAG:Ce-based white light-emitting diode (LED) due to the lack of red spectral component, core/shell/shell CdSe/CdS/ZnS quantum dots (QDs) were synthesized and blended into nano-YAG:Ce3+ phosphors. Prominent spectral evolution has been achieved by increasing the content of QDs. A white LED combining a blue LED with the blends of nano-YAG phosphors and orange- and red-emission QDs with a weight ratio of 1:1:1 was obtained. This kind of white LED showed excellent white light with luminescent efficiency, color coordinates, CRI and correlated color temperature (CCT) of 82.5 lm/W, (0.3264, 0.3255), 91 and 4580 K, respectively.

  5. Development of an airborne three-channel LED-based broadband cavity enhanced absorption spectrometer: towards an improved understanding of nighttime chemistry of NO3 and N2O5 in northwest Europe

    NASA Astrophysics Data System (ADS)

    Ouyang, Bin

    2015-04-01

    A three-channel cavity-enhanced absorption spectrometer capable of covering a broad UV-vis spectrum range has been developed in Cambridge for deployment on board the UK FAAM BAe-146 atmospheric research aircraft for measuring in situ concentrations of important atmospheric absorbers such as NO3, N2O5, NO2, IO and H2O and also aerosol extinction. So far this instrument has been deployed in two aircraft campaigns (the ROle of Nighttime chemistry in controlling the Oxidative Capacity of the atmOsphere, RONOCO, during July 2010 and January 2011; and the Coordinated Airborne Studies in the Tropics, CAST, during February 2014) with focuses on measuring NO2/NO3/N2O5 (for RONOCO) and IO (for CAST). In this talk, I will start by briefly presenting the working principle, design consideration, sensitivity test as well as intercomparison results of this novel aircraft instrument. I will then move on to present recent results from the analysis of the RONOCO campaign data, to illustrate the spatial and temporal variability of nighttime chemistry processes revealed by the high-resolution NO3 and N2O5 data collected. Significant improvements were made towards a better understanding of the oxidation of reactive VOCs by NO3 and O3 and the contribution of peroxy radicals (HO2 and RO2, of which only HO2 was successfully measured) to NO3 direct losses, and towards determining factors (organics and nitrate components of the aerosol particles, and relative humidity) that greatly influence the rate of N2O5 uptake by aerosol particles as well as directly probing the role of cloud, rain and ice scavenging in removing N2O5, in this typical northwest European environment.

  6. FAST TRACK COMMUNICATION: Intense violet-blue emitting (CaCl2/SiO2) : Eu2+ phosphor powders for applications in UV-LED based phototherapy illuminators

    NASA Astrophysics Data System (ADS)

    Hao, Zhendong; Zhang, Jiahua; Zhang, Xia; Ren, Xinguang; Luo, Yongshi; Lu, Shaozhe; Wang, Xiaojun

    2008-09-01

    An intense violet-blue emitting (CaCl2/SiO2) : Eu2+ phosphor with a composition of 25% CaCl2 and 75% SiO2 is prepared by a solid state reaction. The phosphor emits at 427 nm with a narrow bandwidth of 21 nm. The photoluminescence (PL) intensities and fluorescence lifetimes are studied as a function of Eu2+ concentrations. It is observed that the PL intensity of (CaCl2/SiO2) : Eu2+ can be 30% higher than that of commercial Sr2P2O7 : Eu2+ phosphor under 395 nm excitation. (CaCl2/SiO2) : Eu2+ would be a promising new phosphor for converting near-ultraviolet radiation to violet-blue emission for a novel phototherapy illuminator using a near-ultraviolet (~395 nm) light emitting diode as the excitation source.

  7. Expert systems and fuzzy systems

    SciTech Connect

    Negoita, C.

    1985-01-01

    This book examines the design of the expert computer system and how fuzzy systems can be used to deal with imprecise information. As the author explores the effects of semantic systems on decision support systems, he asserts that the utilization of fuzzy set theory can help an expert system draw from its knowledge base more efficiently and therefore make more accurate and reliable decisions. The book includes realistic status reports in approximate reasoning and knowledge representation that are supported by a ''theory of categories'' mathematical approach. The differences between symbolic and semantic manipulation are outline, and detailed information is given on the actual theory of knowledge-based systems.

  8. System Effectiveness

    SciTech Connect

    Powell, Danny H; Elwood Jr, Robert H

    2011-01-01

    An effective risk assessment system is needed to address the threat posed by an active or passive insider who, acting alone or in collusion, could attempt diversion or theft of nuclear material. It is critical that a nuclear facility conduct a thorough self-assessment of the material protection, control, and accountability (MPC&A) system to evaluate system effectiveness. Self-assessment involves vulnerability analysis and performance testing of the MPC&A system. The process should lead to confirmation that mitigating features of the system effectively minimize the threat, or it could lead to the conclusion that system improvements or upgrades are necessary to achieve acceptable protection against the threat. Analysis of the MPC&A system is necessary to understand the limits and vulnerabilities of the system to internal threats. Self-assessment helps the facility be prepared to respond to internal threats and reduce the risk of theft or diversion of nuclear material. MSET is a self-assessment or inspection tool utilizing probabilistic risk assessment (PRA) methodology to calculate the system effectiveness of a nuclear facility's MPC&A system. MSET analyzes the effectiveness of an MPC&A system based on defined performance metrics for MPC&A functions based on U.S. and international best practices and regulations. A facility's MC&A system can be evaluated at a point in time and reevaluated after upgrades are implemented or after other system changes occur. The total system or specific subareas within the system can be evaluated. Areas of potential performance improvement or system upgrade can be assessed to determine where the most beneficial and cost-effective improvements should be made. Analyses of risk importance factors show that sustainability is essential for optimal performance. The analyses reveal where performance degradation has the greatest detrimental impact on total system risk and where performance improvements have the greatest reduction in system risk

  9. Cryogenic Systems

    NASA Astrophysics Data System (ADS)

    Hosoyama, Kenji

    2002-02-01

    In this lecture we discuss the principle of method of cooling to a very low temperature, i.e. cryogenic. The "gas molecular model" will be introduced to explain the mechanism cooling by the expansion engine and the Joule-Thomson expansion valve. These two expansion processes are normally used in helium refrigeration systems to cool the process gas to cryogenic temperature. The reverse Carnot cycle will be discussed in detail as an ideal refrigeration cycle. First the fundamental process of liquefaction and refrigeration cycles will be discussed, and then the practical helium refrigeration system. The process flow of the system and the key components; -compressor, expander, and heat exchanger- will be discussed. As an example of an actual refrigeration system, we will use the cryogenic system for the KEKB superconducting RF cavity. We will also discuss the liquid helium distribution system, which is very important, especially for the cryogenic systems used in accelerator applications. 1 Principles of Cooling and Fundamental Cooling Cycle 2 Expansion engine, Joule-Thomson expansion, kinetic molecular theory, and enthalpy 3 Liquefaction Systems 4 Refrigeration Systems 5 Practical helium liquefier/refrigeration system 6 Cryogenic System for TRISTAN Superconducting RF Cavity

  10. [Information systems].

    PubMed

    Rodríguez Maniega, José Antonio; Trío Maseda, Reyes

    2005-03-01

    The arrival of victims of the terrorist attacks of 11 March at the hospital put the efficiency of its information systems to the test. To be most efficient, these systems should be simple and directed, above all, to the follow-up of victims and to providing the necessary information to patients and families. A specific and easy to use system is advisable. PMID:15771852

  11. Geothermal systems

    NASA Technical Reports Server (NTRS)

    Mohl, C.

    1978-01-01

    Several tasks of JPL related to geothermal energy are discussed. The major task is the procurement and test and evaluation of a helical screw drive (wellhead unit). A general review of geothermal energy systems is given. The presentation focuses attention on geothermal reservoirs in California, with graphs and charts to support the discussion. Included are discussions on cost analysis, systems maintenance, and a comparison of geothermal and conventional heating and cooling systems.

  12. Systemic darwinism.

    PubMed

    Winther, Rasmus Grønfeldt

    2008-08-19

    Darwin's 19th century evolutionary theory of descent with modification through natural selection opened up a multidimensional and integrative conceptual space for biology. We explore three dimensions of this space: explanatory pattern, levels of selection, and degree of difference among units of the same type. Each dimension is defined by a respective pair of poles: law and narrative explanation, organismic and hierarchical selection, and variational and essentialist thinking. As a consequence of conceptual debates in the 20th century biological sciences, the poles of each pair came to be seen as mutually exclusive opposites. A significant amount of 21st century research focuses on systems (e.g., genomic, cellular, organismic, and ecological/global). Systemic Darwinism is emerging in this context. It follows a "compositional paradigm" according to which complex systems and their hierarchical networks of parts are the focus of biological investigation. Through the investigation of systems, Systemic Darwinism promises to reintegrate each dimension of Darwin's original logical space. Moreover, this ideally and potentially unified theory of biological ontology coordinates and integrates a plurality of mathematical biological theories (e.g., self-organization/structure, cladistics/history, and evolutionary genetics/function). Integrative Systemic Darwinism requires communal articulation from a plurality of perspectives. Although it is more general than these, it draws on previous advances in Systems Theory, Systems Biology, and Hierarchy Theory. Systemic Darwinism would greatly further bioengineering research and would provide a significantly deeper and more critical understanding of biological reality. PMID:18697926

  13. Anticipatory systems as linguistic systems

    NASA Astrophysics Data System (ADS)

    Ekdahl, Bertil

    2000-05-01

    The idea of system is well established although not well defined. What makes up a system depends on the observer. Thinking in terms of systems is only a convenient way to conceptualize organizations, natural or artificial, that show coherent properties. Among all properties, which can be ascribed to systems, one property seems to be more outstanding than others, namely that of being anticipatory. In nature, anticipatory properties are found only in living organizations. In this way it can be said to separate non-living systems from living because there is no indication that any natural phenomenon occurring in systems where there is no indication of life is anticipatory. The characteristic of living systems is that they are exposed to the evolution contrary to causal systems that do not undergo changes due to the influence of the environment. Causal systems are related to the past in such a way that subsequent situations can be calculated from knowledge of past situations. In causal systems the past is the cause of the present and there is no reference to the future as a determining agent, contrary to anticipatory systems where expectations are the cause of the present action. Since anticipatory properties are characteristic of living systems, this property, as all other properties in living systems, is a result of the evolution and can be found in plants as well as in animals. Thus, it is not only tied to consciousness but is found at a more basic level, i.e., in the interplay between genotype and phenotype. Anticipation is part of the genetic language in such a way that appropriate actions, for events in the anticipatory systems environment, are inscribed in the genes. Anticipatory behavior, as a result of the interpretation of the genetic language, has been selected by the evolution. In this paper anticipatory systems are regarded as linguistic systems and I argue that as such anticipation cannot be fragmented but must be holistically studied. This has the

  14. Educational Systems.

    ERIC Educational Resources Information Center

    Archer, Margaret

    1981-01-01

    Presents a general review of research on educational systems, with emphasis on variations in the definition of an educational system, neglected questions, areas of major concern, research needs, traditional and modern stands in the sociology of education, educational politics, and researcher bias. (DB)

  15. Systemic Change.

    ERIC Educational Resources Information Center

    Tosti, Donald T.

    2000-01-01

    Examines three factors contributing to organizational success: use of a systemic model to design and guide the change effort; analysis of interdependencies within the system and of the change potential; and use of communication methods to help ensure that the change will be supported. Presents characteristics of successful change efforts with…

  16. Power system

    DOEpatents

    Hickam, Christopher Dale

    2008-03-18

    A power system includes a prime mover, a transmission, and a fluid coupler having a selectively engageable lockup clutch. The fluid coupler may be drivingly connected between the prime mover and the transmission. Additionally, the power system may include a motor/generator drivingly connected to at least one of the prime mover and the transmission. The power-system may also include power-system controls configured to execute a control method. The control method may include selecting one of a plurality of modes of operation of the power system. Additionally, the control method may include controlling the operating state of the lockup clutch dependent upon the mode of operation selected. The control method may also include controlling the operating state of the motor/generator dependent upon the mode of operation selected.

  17. Processing system

    NASA Technical Reports Server (NTRS)

    Hilland, J. E.

    1983-01-01

    To implement the analysis techniques and to provide end-to-end processing, a system was designed with the following capabilities: receive and catalog data from many sources; organize the data on mass storage for rapid access; edit for reasonableness; create new data sets by sorting on parameter, averaging and merging; provide statistical analysis and display tools; and distribute data on demand. Consideration was given to developing a flexible system that could meet immediate workshop needs and respond to future requirements. System architecture and data set details implemented are discussed.

  18. Electronic system

    DOEpatents

    Robison, G H; Dickson, J F

    1960-11-15

    An electronic system is designed for indicating the occurrence of a plurality of electrically detectable events within predetermined time intervals. The system comprises separate input means electrically associated with the events under observation an electronic channel associated with each input means, including control means and indicating means; timing means adapted to apply a signal from the input means after a predetermined time to the control means to deactivate each of the channels; and means for resetting the system to its initial condition after the observation of each group of events. (D.L.C.)

  19. System identification

    NASA Astrophysics Data System (ADS)

    Juang, Jer-Nan

    Major issues in system identification are summarized and recent advances are reviewed. Modal testing and system identification used in control theory are examined, and the mathematical relationships and conversions of the models appropriate to modal testing and those appropriate to modern control design methods are discussed. The importance of obtaining input and output matrices in modal testing is emphasized, and the changes that may be needed in modal testing procedures to meet the needs of the control system designer are addressed. Directions for future research are considered.

  20. Saturn Systems.

    PubMed

    U Rehman, Habib; McKee, Nida A; McKee, Michael L

    2016-01-15

    Several ring systems (Saturn systems) have been studied using DFT methods that include dispersion effects. Comparison with X-ray structures are made with three systems, and the agreement is quite good. Binding enthalpies and binding free energies in dichloromethane and toluene have been computed. The effect of an encapsulated lithium cation is accessed by comparing C60 @(C6 H4 )10 and [Li@C60 @(C6 H4 )10 ](+). The [Li@C60 ](+) cation is a much better acceptor than C60 which leads to greater donor-acceptor interactions and larger charge transfer from the ring to [Li@C60 ](+). PMID:26096724

  1. Lymph system

    MedlinePlus

    ... the lymph nodes make more infection-fighting white blood cells, which cause the nodes to swell. The swollen nodes are sometimes felt in the neck, under the arms, and groin. The lymph system includes the: Tonsils Adenoids Spleen Thymus

  2. Respiratory system

    NASA Technical Reports Server (NTRS)

    Bartlett, R. G., Jr.

    1973-01-01

    The general anatomy and function of the human respiratory system is summarized. Breathing movements, control of breathing, lung volumes and capacities, mechanical relations, and factors relevant to respiratory support and equipment design are discussed.

  3. [Systemic urticarias].

    PubMed

    Hachulla, E

    2003-05-01

    Systemic urticaria remains a challenge in terms of etiology, investigation and management. Most of cases are urticarial vasculitis consequence of inflammatory injury of capillaries and postcapillary venules in the skin. If hypocomplementemic urticarial vasculitis syndrome is a classical cause, the majority of patients have an underlying systemic disease like systemic lupus erythematosus, Sjögren's syndrome, mixed cryoglobulinemia, Still disease or cancer. Others systemic urticaria have been reported without clearly evidence of vasculitis like in primary or acquired angioedema, hereditary periodic fever syndromes and in some thyroiditis. Diagnosis needs a step to step procedure. Treatment depends the underlying disease. Some patients respond to nonsteroidal antiinflammatory drugs, some other need corticosteroids or immunosuppression. If urticarial vasculitis seems isolated in the absence of chronic obstructive pulmonary disease, antihistamines, nonsteroidal antiinflammatory drugs, colchicine, dapsone or hydroxychloroquine must be first used. PMID:12843810

  4. SAMPLING SYSTEM

    DOEpatents

    Hannaford, B.A.; Rosenberg, R.; Segaser, C.L.; Terry, C.L.

    1961-01-17

    An apparatus is given for the batch sampling of radioactive liquids such as slurries from a system by remote control, while providing shielding for protection of operating personnel from the harmful effects of radiation.

  5. Microelectromechanical Systems

    NASA Technical Reports Server (NTRS)

    Gabriel, Kaigham J.

    1995-01-01

    Micro-electromechanical systems (MEMS) is an enabling technology that merges computation and communication with sensing and actuation to change the way people and machines interact with the physical world. MEMS is a manufacturing technology that will impact widespread applications including: miniature inertial measurement measurement units for competent munitions and personal navigation; distributed unattended sensors; mass data storage devices; miniature analytical instruments; embedded pressure sensors; non-invasive biomedical sensors; fiber-optics components and networks; distributed aerodynamic control; and on-demand structural strength. The long term goal of ARPA's MEMS program is to merge information processing with sensing and actuation to realize new systems and strategies for both perceiving and controlling systems, processes, and the environment. The MEMS program has three major thrusts: advanced devices and processes, system design, and infrastructure.

  6. Recommender systems

    NASA Astrophysics Data System (ADS)

    Lü, Linyuan; Medo, Matúš; Yeung, Chi Ho; Zhang, Yi-Cheng; Zhang, Zi-Ke; Zhou, Tao

    2012-10-01

    The ongoing rapid expansion of the Internet greatly increases the necessity of effective recommender systems for filtering the abundant information. Extensive research for recommender systems is conducted by a broad range of communities including social and computer scientists, physicists, and interdisciplinary researchers. Despite substantial theoretical and practical achievements, unification and comparison of different approaches are lacking, which impedes further advances. In this article, we review recent developments in recommender systems and discuss the major challenges. We compare and evaluate available algorithms and examine their roles in the future developments. In addition to algorithms, physical aspects are described to illustrate macroscopic behavior of recommender systems. Potential impacts and future directions are discussed. We emphasize that recommendation has great scientific depth and combines diverse research fields which makes it interesting for physicists as well as interdisciplinary researchers.

  7. Systems and Components Fuel Delivery System, Water Delivery System, ...

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

    Systems and Components - Fuel Delivery System, Water Delivery System, Derrick Crane System, and Crane System Details - Marshall Space Flight Center, F-1 Engine Static Test Stand, On Route 565 between Huntsville and Decatur, Huntsville, Madison County, AL

  8. Systems Studies

    SciTech Connect

    Graham, R.L.

    1998-03-17

    The Systems Studies Activity had two objectives: (1) to investigate nontechnical barriers to the deployment of biomass production and supply systems and (2) to enhance and extend existing systems models of bioenergy supply and use. For the first objective, the Activity focused on existing bioenergy markets. Four projects were undertaken: a comparative analysis of bioenergy in Sweden and Austria; a one-day workshop on nontechnical barriers jointly supported by the Production Systems Activity; the development and testing of a framework for analyzing barriers and drivers to bioenergy markets; and surveys of wood pellet users in Sweden, Austria and the US. For the second objective, two projects were undertaken. First, the Activity worked with the Integrated BioEnergy Systems (TBS) Activity of TEA Bioenergy Task XIII to enhance the BioEnergy Assessment Model (BEAM). This model is documented in the final report of the IBS Activity. The Systems Studies Activity contributed to enhancing the feedstock portion of the model by developing a coherent set of willow, poplar, and switchgrass production modules relevant to both the US and the UK. The Activity also developed a pretreatment module for switchgrass. Second, the Activity sponsored a three-day workshop on modeling bioenergy systems with the objectives of providing an overview of the types of models used to evaluate bioenergy and promoting communication among bioenergy modelers. There were nine guest speakers addressing different types of models used to evaluate different aspects of bioenergy, ranging from technoeconomic models based on the ASPEN software to linear programming models to develop feedstock supply curves for the US. The papers from this workshop have been submitted to Biomass and Bioenergy and are under editorial review.

  9. Systemic fluoride.

    PubMed

    Sampaio, Fábio Correia; Levy, Steven Marc

    2011-01-01

    There is substantial evidence that fluoride, through different applications and formulas, works to control caries development. The first observations of fluoride's effects on dental caries were linked to fluoride naturally present in the drinking water, and then from controlled water fluoridation programs. Other systemic methods to deliver fluoride were later suggested, including dietary fluoride supplements such as salt and milk. These systemic methods are now being questioned due to the fact that many studies have indicated that fluoride's action relies mainly on its post-eruptive effect from topical contact with the tooth structure. It is known that even the methods of delivering fluoride known as 'systemic' act mainly through a topical effect when they are in contact with the teeth. The effectiveness of water fluoridation in many geographic areas is lower than in previous eras due to the widespread use of other fluoride modalities. Nevertheless, this evidence should not be interpreted as an indication that systemic methods are no longer relevant ways to deliver fluoride on an individual basis or for collective health programs. Caution must be taken to avoid excess ingestion of fluoride when prescribing dietary fluoride supplements for children in order to minimize the risk of dental fluorosis, particularly if there are other relevant sources of fluoride intake - such as drinking water, salt or milk and/or dentifrice. Safe and effective doses of fluoride can be achieved when combining topical and systemic methods. PMID:21701196

  10. Systemic trauma.

    PubMed

    Goldsmith, Rachel E; Martin, Christina Gamache; Smith, Carly Parnitzke

    2014-01-01

    Substantial theoretical, empirical, and clinical work examines trauma as it relates to individual victims and perpetrators. As trauma professionals, it is necessary to acknowledge facets of institutions, cultures, and communities that contribute to trauma and subsequent outcomes. Systemic trauma-contextual features of environments and institutions that give rise to trauma, maintain it, and impact posttraumatic responses-provides a framework for considering the full range of traumatic phenomena. The current issue of the Journal of Trauma & Dissociation is composed of articles that incorporate systemic approaches to trauma. This perspective extends conceptualizations of trauma to consider the influence of environments such as schools and universities, churches and other religious institutions, the military, workplace settings, hospitals, jails, and prisons; agencies and systems such as police, foster care, immigration, federal assistance, disaster management, and the media; conflicts involving war, torture, terrorism, and refugees; dynamics of racism, sexism, discrimination, bullying, and homophobia; and issues pertaining to conceptualizations, measurement, methodology, teaching, and intervention. Although it may be challenging to expand psychological and psychiatric paradigms of trauma, a systemic trauma perspective is necessary on both scientific and ethical grounds. Furthermore, a systemic trauma perspective reflects current approaches in the fields of global health, nursing, social work, and human rights. Empirical investigations and intervention science informed by this paradigm have the potential to advance scientific inquiry, lower the incidence of a broader range of traumatic experiences, and help to alleviate personal and societal suffering. PMID:24617751

  11. Turbine system

    DOEpatents

    McMahan, Kevin Weston; Dillard, Daniel Jackson

    2016-05-03

    A turbine system is disclosed. The turbine system includes a transition duct having an inlet, an outlet, and a passage extending between the inlet and the outlet and defining a longitudinal axis, a radial axis, and a tangential axis. The outlet of the transition duct is offset from the inlet along the longitudinal axis and the tangential axis. The turbine system further includes a turbine section connected to the transition duct. The turbine section includes a plurality of shroud blocks at least partially defining a hot gas path, a plurality of buckets at least partially disposed in the hot gas path, and a plurality of nozzles at least partially disposed in the hot gas path. At least one of a shroud block, a bucket, or a nozzle includes means for withstanding high temperatures.

  12. Memory systems.

    PubMed

    Wolk, David A; Budson, Andrew E

    2010-08-01

    Converging evidence from patient and neuroimaging studies suggests that memory is a collection of abilities that use different neuroanatomic systems. Neurologic injury may impair one or more of these memory systems. Episodic memory allows us to mentally travel back in time and relive an episode of our life. Episodic memory depends on the hippocampus, other medial temporal lobe structures, the limbic system, and the frontal lobes, as well as several other brain regions. Semantic memory provides our general knowledge about the world and is unconnected to any specific episode of our life. Although semantic memory likely involves much of the neocortex, the inferolateral temporal lobes (particularly the left) are most important. Procedural memory enables us to learn cognitive and behavioral skills and algorithms that operate at an automatic, unconscious level. Damage to the basal ganglia, cerebellum, and supplementary motor area often impair procedural memory. PMID:22810510

  13. Computer systems

    NASA Technical Reports Server (NTRS)

    Olsen, Lola

    1992-01-01

    In addition to the discussions, Ocean Climate Data Workshop hosts gave participants an opportunity to hear about, see, and test for themselves some of the latest computer tools now available for those studying climate change and the oceans. Six speakers described computer systems and their functions. The introductory talks were followed by demonstrations to small groups of participants and some opportunities for participants to get hands-on experience. After this familiarization period, attendees were invited to return during the course of the Workshop and have one-on-one discussions and further hands-on experience with these systems. Brief summaries or abstracts of introductory presentations are addressed.

  14. Complex Systems

    PubMed Central

    Goldberger, Ary L.

    2006-01-01

    Physiologic systems in health and disease display an extraordinary range of temporal behaviors and structural patterns that defy understanding based on linear constructs, reductionist strategies, and classical homeostasis. Application of concepts and computational tools derived from the contemporary study of complex systems, including nonlinear dynamics, fractals and “chaos theory,” is having an increasing impact on biology and medicine. This presentation provides a brief overview of an emerging area of biomedical research, including recent applications to cardiopulmonary medicine and chronic obstructive lung disease. PMID:16921107

  15. Lindenmayer Systems

    NASA Astrophysics Data System (ADS)

    Honkala, Juha

    The theory of Lindenmayer systems studies free monoid morphisms, free monoid substitutions and their iterations. In this chapter, we discuss similar ideas in a more general framework. Instead of a free monoid, we consider the free semi-algebra S<Σ*> consisting of polynomials with non-commuting variables in Σ and coefficients in a semiring S and we study the iteration of endomorphisms of S<Σ*>. We allow various modes of iteration and we consider various classes of morphisms. Classical L systems are obtained as special cases by taking S to be the Boolean semiring. Our approach also generalizes the theory of algebraic series in noncommuting variables.

  16. ELECTRONIC SYSTEM

    DOEpatents

    Robison, G.H. et al.

    1960-11-15

    An electronic system is described for indicating the occurrence of a plurality of electrically detectable events within predetermined time intervals. It is comprised of separate input means electrically associated with the events under observation: an electronic channel associated with each input means including control means and indicating means; timing means associated with each of the input means and the control means and adapted to derive a signal from the input means and apply it after a predetermined time to the control means to effect deactivation of each of the channels; and means for resetting the system to its initial condition after observation of each group of events.

  17. Microbiology System

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Technology originating in a NASA-sponsored study of the measurement of microbial growth in zero gravity led to the development of Biomerieux Vitek, Inc.'s VITEK system. VITEK provides a physician with accurate diagnostic information and identifies the most effective medication. Test cards are employed to identify organisms and determine susceptibility to antibiotics. A photo-optical scanner scans the card and monitors changes in the growth of cells contained within the card. There are two configurations - VITEK and VITEK JR as well as VIDAS, a companion system that detects bacteria, viruses, etc. from patient specimens. The company was originally created by McDonnell Douglas, the NASA contractor.

  18. The FLARE™ Intraoperative Near-Infrared Fluorescence Imaging System: A First-in-Human Clinical Trial in Perforator Flap Breast Reconstruction

    PubMed Central

    Lee, Bernard T.; Hutteman, Merlijn; Gioux, Sylvain; Stockdale, Alan; Lin, Samuel J.; Ngo, Long H.; Frangioni, John V.

    2010-01-01

    Background The ability to determine flap perfusion in reconstructive surgery is still primarily based on clinical examination. In this study, we demonstrate the use of an intraoperative, near infrared (NIR) fluorescence imaging system for evaluation of perforator location and flap perfusion. Methods Indocyanine green (ICG) was injected intravenously in six breast cancer patients undergoing a deep inferior epigastric perforator (DIEP) flap breast reconstruction after mastectomy. Three dose levels of ICG were assessed using the Fluorescence-Assisted Resection and Exploration (FLARE™) imaging system. This system uses light emitting diodes (LED) for fluorescence excitation; different from current commercially available systems. In this pilot study, the operating surgeons were blinded to the imaging results. Results Use of the FLARE™ system was successful in all six study subjects with no complications or sequelae. Among the three dose levels, 4 mg per injection resulted in the highest observed contrast-to-background ratio (CBR), signal-to-background ratio, and signal-to-noise ratio. However, due to small sample size, we did not have sufficient power to detect statistical significance for these pairwise comparisons at the multiple-comparison adjusted type-I error of 0.017. Six mg per injection provided a similar CBR, but also a higher residual background signal. Conclusions Based on this pilot study, we conclude that NIR assessment of perforator flap breast reconstruction is feasible with an LED based system, and that a dose of 4 mg of ICG per injection yields the best observed CBR compared to a dose of 2 or 6 mg for assessment of flap perfusion. PMID:21042103

  19. Calibration of a wide-field frequency-domain fluorescence lifetime microscopy system using light emitting diodes as light sources.

    PubMed

    Elder, A D; Frank, J H; Swartling, J; Dai, X; Kaminski, C F

    2006-11-01

    High brightness light emitting diodes are an inexpensive and versatile light source for wide-field frequency-domain fluorescence lifetime imaging microscopy. In this paper a full calibration of an LED based fluorescence lifetime imaging microscopy system is presented for the first time. A radio-frequency generator was used for simultaneous modulation of light emitting diode (LED) intensity and the gain of an intensified charge coupled device (CCD) camera. A homodyne detection scheme was employed to measure the demodulation and phase shift of the emitted fluorescence, from which phase and modulation lifetimes were determined at each image pixel. The system was characterized both in terms of its sensitivity to measure short lifetimes (500 ps to 4 ns), and its capability to distinguish image features with small lifetime differences. Calibration measurements were performed in quenched solutions containing Rhodamine 6G dye and the results compared to several independent measurements performed with other measurement methodologies, including time correlated single photon counting, time gated detection, and acousto optical modulator (AOM) based modulation of excitation sources. Results are presented from measurements and simulations. The effects of limited signal-to-noise ratios, baseline drifts and calibration errors are discussed in detail. The implications of limited modulation bandwidth of high brightness, large area LED devices ( approximately 40 MHz for devices used here) are presented. The results show that phase lifetime measurements are robust down to sub ns levels, whereas modulation lifetimes are prone to errors even at large signal-to-noise ratios. Strategies for optimizing measurement fidelity are discussed. Application of the fluorescence lifetime imaging microscopy system is illustrated with examples from studies of molecular mixing in microfluidic devices and targeted drug delivery research. PMID:17204064

  20. Systems Biology

    SciTech Connect

    Wiley, H S.

    2006-06-01

    The biology revolution over the last 50 years has been driven by the ascendancy of molecular biology. This was enthusiastically embraced by most biologists because it took us into increasingly familiar territory. It took mysterious processes, such as the replication of genetic material and assigned them parts that could be readily understood by the human mind. When we think of ''molecular machines'' as being the underlying basis of life, we are using a paradigm derived from everyday experience. However, the price that we paid was a relentless drive towards reductionism and the attendant balkanization of biology. Now along comes ''systems biology'' that promises us a solution to the problem of ''knowing more and more about less and less''. Unlike molecular biology, systems biology appears to be taking us into unfamiliar intellectual territory, such as statistics, mathematics and computer modeling. Not surprisingly, systems biology has met with widespread skepticism and resistance. Why do we need systems biology anyway and how does this new area of research promise to change the face of biology in the next couple of decades?

  1. System Dynamics

    NASA Astrophysics Data System (ADS)

    Morecroft, John

    System dynamics is an approach for thinking about and simulating situations and organisations of all kinds and sizes by visualising how the elements fit together, interact and change over time. This chapter, written by John Morecroft, describes modern system dynamics which retains the fundamentals developed in the 1950s by Jay W. Forrester of the MIT Sloan School of Management. It looks at feedback loops and time delays that affect system behaviour in a non-linear way, and illustrates how dynamic behaviour depends upon feedback loop structures. It also recognises improvements as part of the ongoing process of managing a situation in order to achieve goals. Significantly it recognises the importance of context, and practitioner skills. Feedback systems thinking views problems and solutions as being intertwined. The main concepts and tools: feedback structure and behaviour, causal loop diagrams, dynamics, are practically illustrated in a wide variety of contexts from a hot water shower through to a symphony orchestra and the practical application of the approach is described through several real examples of its use for strategic planning and evaluation.

  2. Metric System.

    ERIC Educational Resources Information Center

    Del Mod System, Dover, DE.

    This autoinstructional unit deals with the identification of units of measure in the metric system and the construction of relevant conversion tables. Students in middle school or in grade ten, taking a General Science course, can handle this learning activity. It is recommended that high, middle or low level achievers can use the program.…

  3. Irrigation System

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Under contract with Marshall Space Flight Center, Midwest Research Institute compiled a Lubrication Handbook intended as a reference source for designers and manufacturers of aerospace hardware and crews responsible for maintenance of such equipment. Engineers of Lindsay Manufacturing Company learned of this handbook through NASA Tech Briefs and used it for supplemental information in redesigning gear boxes for their center pivot agricultural irrigation system.

  4. Cardiovascular system

    MedlinePlus Videos and Cool Tools

    The cardiovascular system is composed of the heart and the network of arteries, veins, and capillaries that transport blood throughout the body. The ... which they are eliminated. Most of the blood is made up of a watery, protein-laden fluid ...

  5. Auditory system

    NASA Technical Reports Server (NTRS)

    Ades, H. W.

    1973-01-01

    The physical correlations of hearing, i.e. the acoustic stimuli, are reported. The auditory system, consisting of external ear, middle ear, inner ear, organ of Corti, basilar membrane, hair cells, inner hair cells, outer hair cells, innervation of hair cells, and transducer mechanisms, is discussed. Both conductive and sensorineural hearing losses are also examined.

  6. Immune System

    EPA Science Inventory

    A properly functioning immune system is essential to good health. It defends the body against infectious agents and in some cases tumor cells. Individuals with immune deficiencies resulting from genetic defects, diseases (e.g., AIDS, leukemia), or drug therapies are more suscepti...

  7. Systems Science

    ERIC Educational Resources Information Center

    Christakis, Alexander; Hammond, Debora; Jackson, Michael; Laszlo, Alexander; Mitroff, Ian; Snowden, Dave; Troncale, Len; Carr-Chellman, Alison; Spector, J. Michael; Wilson, Brent

    2013-01-01

    Scholars representing the field of systems science were asked to identify what they considered to be the most exciting and imaginative work currently being done in their field, as well as how that work might change our understanding. The scholars included Alexander Christakis, Debora Hammond, Michael Jackson, Alexander Laszlo, Ian Mitroff, Dave…

  8. STAR System.

    ERIC Educational Resources Information Center

    Doverspike, James E.

    The STAR System is a developmental guidance approach to be used with elementary school children in the 5th or 6th grades. Two basic purposes underlie STAR: to increase learning potential and to enhance personal growth and development. STAR refers to 4 basic skills: sensory, thinking, adapting, and revising. Major components of the 4 skills are:…

  9. Autonomous, In-situ Instrumentation for Continuous Measurement of Dissolved Copper and Zinc in Aquatic Systems

    NASA Astrophysics Data System (ADS)

    Chase, Z.; Holm, C. E.; Groshong, H.; Yannasch, H.; Johnson, K.

    2008-12-01

    Quantifying trace metal concentrations in aquatic systems is complicated, costly, and prone to contamination artifacts. Consequently, very little is known about high-frequency temporal variability (hours-to-days) in metal concentrations. Such data can be used to assess the origin, fate and impact of toxic trace metals such as copper and zinc. We have developed autonomous, in-situ instrumentation to measure dissolved copper and zinc concentrations, suitable for deployment on time scales from weeks to a month. Both instruments use the commercially available in-situ nitrate analyzer (YSI 9600) as the base platform. Micro solenoid pumps take in sample and dispense reagent, standard, and blank solutions. Filtration (0.45 μm) and acidification (pH ~1.7) permit a measurement of total dissolved metal. The copper instrument features a custom-made photomultiplier (PMT) based detector and flow-cell. Copper is detected through chemiluminescence of 1-10- phenanthroline. The zinc instrument features a custom-made PMT and LED-based fluorometric detector and flow-cell. Zinc is detected using the fluorescent probe Fluo-Zin3. Averaged over all in-situ estuarine deployments, the copper instrument has a detection limit of 0.8 nM ±0.3 nM, a sample precision of 11% (n=612), and an accuracy of 17% (compared to discrete samples n=27). The instrument is capable of functioning autonomously for 25 days when sampling every hour and calibrating every six hours. Based on bench tests, the zinc instrument has a detection limit of ~2 nM and a sample precision better than 2%. The hardware and analytical approach can be easily modified to detect additional metals by chemiluminescence (e.g. Co, Fe, Mn) and fluorescence (e.g. Al, Cd).

  10. Surveying System

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Sunrise Geodetic Surveys are setting up their equipment for a town survey. Their equipment differs from conventional surveying systems that employ transit rod and chain to measure angles and distances. They are using ISTAC Inc.'s Model 2002 positioning system, which offers fast accurate surveying with exceptional signals from orbiting satellites. The special utility of the ISTAC Model 2002 is that it can provide positioning of the highest accuracy from Navstar PPS signals because it requires no knowledge of secret codes. It operates by comparing the frequency and time phase of a Navstar signal arriving at one ISTAC receiver with the reception of the same set of signals by another receiver. Data is computer processed and translated into three dimensional position data - latitude, longitude and elevation.

  11. Burner systems

    DOEpatents

    Doherty, Brian J.

    1984-07-10

    A burner system particularly useful for downhole deployment includes a tubular combustion chamber unit housed within a tubular coolant jacket assembly. The combustion chamber unit includes a monolithic tube of refractory material whose inner surface defines the combustion zone. A metal reinforcing sleeve surrounds and extends the length of the refractory tube. The inner surface of the coolant jacket assembly and outer surface of the combustion chamber unit are dimensioned so that those surfaces are close to one another in standby condition so that the combustion chamber unit has limited freedom to expand with that expansion being stabilized by the coolant jacket assembly so that compression forces in the refractory tube do not exceed about one-half the safe compressive stress of the material; and the materials of the combustion chamber unit are selected to establish thermal gradient parameters across the combustion chamber unit to maintain the refractory tube in compression during combustion system start up and cool down sequences.

  12. Tychonic System

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    The world system proposed in 1583 by the Danish astronomer Tycho Brahe (1546-1601). Unable to accept the Copernican doctrine that the Earth moves around the Sun, he put forward the view, later disproved by Kepler (1571-1630), that the planets move around the Sun, but the Sun and Moon move around the Earth. The theory explained the observed variations of the phases of Venus, for which the Ptolemai...

  13. Copernican System

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    The heliocentric (i.e. `Sun-centered') theory proposed by the Polish astronomer Nicolaus Copernicus (1473-1543), and published by him in 1543 in his book, De Revolutionibus Orbium Coelestium. In this system Copernicus placed the Sun at the center of the universe and regarded the Earth and the planets as moving around it in circular orbits. Because of his retention of the notion of circular motion...

  14. Gasification system

    DOEpatents

    Haldipur, Gaurang B.; Anderson, Richard G.; Cherish, Peter

    1985-01-01

    A method and system for injecting coal and process fluids into a fluidized bed gasification reactor. Three concentric tubes extend vertically upward into the fluidized bed. Coal particulates in a transport gas are injected through an inner tube, and an oxygen rich mixture of oxygen and steam are injected through an inner annulus about the inner tube. A gaseous medium relatively lean in oxygen content, such as steam, is injected through an annulus surrounding the inner annulus.

  15. Gasification system

    DOEpatents

    Haldipur, Gaurang B.; Anderson, Richard G.; Cherish, Peter

    1983-01-01

    A method and system for injecting coal and process fluids into a fluidized bed gasification reactor. Three concentric tubes extend vertically upward into the fluidized bed. Coal particulates in a transport gas are injected through an inner tube, and an oxygen rich mixture of oxygen and steam are injected through an inner annulus about the inner tube. A gaseous medium relatively lean in oxygen content, such as steam, is injected through an annulus surrounding the inner annulus.

  16. Mine system

    SciTech Connect

    Stoppani, B.R.

    1983-10-04

    A mine system comprises at least one mining machine adapted to haul itself, in a reciprocating manner, along a mineral face, and a control box housing means to control the various electrical elements of the machine(s), the box being located in a mine roadway at one end of the mineral face along which the machine(s) is reciprocating, and the box being electrically connected to a terminal box housed in a body of the machine(s).

  17. Imaging System

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The 1100C Virtual Window is based on technology developed under NASA Small Business Innovation (SBIR) contracts to Ames Research Center. For example, under one contract Dimension Technologies, Inc. developed a large autostereoscopic display for scientific visualization applications. The Virtual Window employs an innovative illumination system to deliver the depth and color of true 3D imaging. Its applications include surgery and Magnetic Resonance Imaging scans, viewing for teleoperated robots, training, and in aviation cockpit displays.

  18. Security system

    DOEpatents

    Baumann, Mark J.; Kuca, Michal; Aragon, Mona L.

    2016-02-02

    A security system includes a structure having a structural surface. The structure is sized to contain an asset therein and configured to provide a forceful breaching delay. The structure has an opening formed therein to permit predetermined access to the asset contained within the structure. The structure includes intrusion detection features within or associated with the structure that are activated in response to at least a partial breach of the structure.

  19. Systemic amyloidosis.

    PubMed

    Wechalekar, Ashutosh D; Gillmore, Julian D; Hawkins, Philip N

    2016-06-25

    Tissue deposition of protein fibrils causes a group of rare diseases called systemic amyloidoses. This Seminar focuses on changes in their epidemiology, the current approach to diagnosis, and advances in treatment. Systemic light chain (AL) amyloidosis is the most common of these conditions, but wild-type transthyretin cardiac amyloidosis (ATTRwt) is increasingly being diagnosed. Typing of amyloid fibrils, a critical determinant of therapy, has improved with the wide availability of laser capture and mass spectrometry from fixed histological tissue sections. Specific and accurate evaluation of cardiac amyloidosis is now possible using cardiac magnetic resonance imaging and cardiac repurposing of bone scintigraphy tracers. Survival in AL amyloidosis has improved markedly as novel chemotherapy agents have become available, but challenges remain in advanced disease. Early diagnosis, a key to better outcomes, still remains elusive. Broadening the amyloid-specific therapeutic landscape to include RNA inhibitors, fibril formation stabilisers and inhibitors, and immunotherapeutic targeting of amyloid deposits holds promise to transform outcomes in systemic amyloidoses. PMID:26719234

  20. Braking system

    DOEpatents

    Norgren, D.U.

    1982-09-23

    A balanced braking system comprising a plurality of braking assemblies located about a member to be braked. Each of the braking assemblies consists of a spring biased piston of a first material fitted into a body of a different material which has a greater contraction upon cooling than the piston material. The piston is provided with a recessed head portion over which is positioned a diaphragm and forming a space therebetween to which is connected a pressurized fluid supply. The diaphragm is controlled by the fluid in the space to contact or withdraw from the member to be braked. A cooling means causes the body within which the piston is fitted to contract more than the piston, producing a tight shrink fit therebetween. The braking system is particularly applicable for selectively braking an arbor of an electron microscope which immobilizes, for example, a vertically adjustable low temperature specimen holder during observation. The system provides balanced braking forces which can be easily removed and re-established with minimal disturbance to arbor location.

  1. Balance System

    NASA Technical Reports Server (NTRS)

    1988-01-01

    TherEx Inc.'s AT-1 Computerized Ataxiameter precisely evaluates posture and balance disturbances that commonly accompany neurological and musculoskeletal disorders. Complete system includes two-strain gauged footplates, signal conditioning circuitry, a computer monitor, printer and a stand-alone tiltable balance platform. AT-1 serves as assessment tool, treatment monitor, and rehabilitation training device. It allows clinician to document quantitatively the outcome of treatment and analyze data over time to develop outcome standards for several classifications of patients. It can evaluate specifically the effects of surgery, drug treatment, physical therapy or prosthetic devices.

  2. Bearing system

    DOEpatents

    Kapich, Davorin D.

    1987-01-01

    A bearing system includes backup bearings for supporting a rotating shaft upon failure of primary bearings. In the preferred embodiment, the backup bearings are rolling element bearings having their rolling elements disposed out of contact with their associated respective inner races during normal functioning of the primary bearings. Displacement detection sensors are provided for detecting displacement of the shaft upon failure of the primary bearings. Upon detection of the failure of the primary bearings, the rolling elements and inner races of the backup bearings are brought into mutual contact by axial displacement of the shaft.

  3. Sterilization System

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Cox Sterile Products, Inc.'s Rapid Heat Transfer Sterilizer employs a heat exchange process that induces rapid air movement; the air becomes the heat transfer medium, maintaining a uniform temperature of 375 degrees Fahrenheit. It features pushbutton controls for three timing cycles for different instrument loads, a six-minute cycle for standard unpackaged instruments, eight minutes for certain specialized dental/medical instruments and 12 minutes for packaged instruments which can then be stored in a drawer in sterile condition. System will stay at 375 degrees all day. Continuous operation is not expensive because of the sterilizer's very low power requirements.

  4. Relaxation System

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Environ Corporation's relaxation system is built around a body lounge, a kind of super easy chair that incorporates sensory devices. Computer controlled enclosure provides filtered ionized air to create a feeling of invigoration, enhanced by mood changing aromas. Occupant is also surrounded by multidimensional audio and the lighting is programmed to change colors, patterns, and intensity periodically. These and other sensory stimulators are designed to provide an environment in which the learning process is stimulated, because research has proven that while an individual is in a deep state of relaxation, the mind is more receptive to new information.

  5. Videobasierte Systeme

    NASA Astrophysics Data System (ADS)

    Knoll, Peter

    Videosensoren spielen für Fahrerassistenz systeme eine zentrale Rolle, da sie die Interpretation visueller Informationen (Objektklassifikation) gezielt unterstützen. Im Heckbereich kann die Video sensorik in der einfachsten Variante die ultraschallbasierte Einparkhilfe bei Einpark- und Rangiervorgängen unterstützen. Beim Nachtsichtsystem NightVision wird das mit Infrarotlicht angestrahlte Umfeld vor dem Fahrzeug mit einer Frontkamera aufgenommen und im Fahrzeugcockpit auf einem Display dem Fahrer angezeigt (s. Nachtsichtsysteme). Andere Fahrerassistenzsysteme verarbeiten die Videosignale und generieren daraus gezielt Informationen, die für eigenständige Funktionen (z. B. Spurverlassenswarner) oder aber als Zusatzinformation für andere Funktionen ausgewertet werden (Sensordatenfusion).

  6. Purification system

    NASA Technical Reports Server (NTRS)

    Flanagan, David T. (Inventor); Gibbons, Randall E. (Inventor)

    1992-01-01

    A system for prolonging the life of a granulated activated charcoal (GAC) water treatment device is disclosed in which an ultraviolet light transparent material is used to constrain water to flow over carbon surfaces. It is configured to receive maximum flux from a UV radiation source for the purpose of preventing microbial proliferation on the carbon surfaces; oxidizing organic contaminants adsorbed from the water onto the carbon surfaces and from biodegradation of adsorbed microbial forms; disinfecting water; and oxidizing organic contaminants in the water.

  7. A transportable system for the in situ recording of color Denisyuk holograms of Greek cultural heritage artifacts in silver halide panchromatic emulsions and an optimized illuminating device for the finished holograms

    NASA Astrophysics Data System (ADS)

    Sarakinos, A.; Lembessis, A.; Zervos, N.

    2013-02-01

    In this paper we will present the Z-Lab transportable color holography system, the HoLoFoS illuminator and results of actual in situ recording of color Denisyuk holograms of artifacts on panchromatic silver halide emulsions. Z-lab and HoLoFoS were developed to meet identified prerequisites of holographic recording of artifacts: a) in situ recording b) a high degree of detail and color reproduction c) a low degree of image distortions. The Z-Lab consists of the Z3RGB camera, its accessories and a mobile darkroom. HoLoFoS is an RGB LED-based lighting device for the display of color holograms. The device is capable of digitally controlled intensity mixing and provides a beam of uniform color cross section. The small footprint and emission characteristics of the device LEDs result in a narrow band, quasi point source at selected wavelengths. A case study in recording and displaying 'Optical Clones' of Greek cultural heritage artifacts with the aforementioned systems will also be presented.

  8. 49 CFR Appendix B to Part 221 - Approved Rear End Marking Devices

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... for or by manufacturers 1. Manufacturer: Star Headlight & Lantern Co., 168 West Main Street, Honeoye Falls, NY 14472. FRA identification Nos. FRA-PLE-STAR-845-F (flasher) and FRA-PLE-STAR-845-C...

  9. 49 CFR Appendix B to Part 221 - Approved Rear End Marking Devices

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... for or by manufacturers 1. Manufacturer: Star Headlight & Lantern Co., 168 West Main Street, Honeoye Falls, NY 14472. FRA identification Nos. FRA-PLE-STAR-845-F (flasher) and FRA-PLE-STAR-845-C...

  10. 49 CFR Appendix B to Part 221 - Approved Rear End Marking Devices

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... for or by manufacturers 1. Manufacturer: Star Headlight & Lantern Co., 168 West Main Street, Honeoye Falls, NY 14472. FRA identification Nos. FRA-PLE-STAR-845-F (flasher) and FRA-PLE-STAR-845-C...

  11. 49 CFR Appendix B to Part 221 - Approved Rear End Marking Devices

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... for or by manufacturers 1. Manufacturer: Star Headlight & Lantern Co., 168 West Main Street, Honeoye Falls, NY 14472. FRA identification Nos. FRA-PLE-STAR-845-F (flasher) and FRA-PLE-STAR-845-C...

  12. 49 CFR Appendix B to Part 221 - Approved Rear End Marking Devices

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... for or by manufacturers 1. Manufacturer: Star Headlight & Lantern Co., 168 West Main Street, Honeoye Falls, NY 14472. FRA identification Nos. FRA-PLE-STAR-845-F (flasher) and FRA-PLE-STAR-845-C...

  13. Development of a microfluidic confocal fluorescence detection system for the hyphenation of nano-LC to on-line biochemical assays

    PubMed Central

    Heus, Ferry; Giera, Martin; de Kloe, Gerdien E.; van Iperen, Dick; Buijs, Joost; Nahar, Tariq T.; Smit, August B.; Lingeman, Henk; de Esch, Iwan J. P.; Niessen, Wilfried M. A.; Irth, Hubertus

    2010-01-01

    One way to profile complex mixtures for receptor affinity is to couple liquid chromatography (LC) on-line to biochemical detection (BCD). A drawback of this hyphenated screening approach is the relatively high consumption of sample, receptor protein and (fluorescently labeled) tracer ligand. Here, we worked toward minimization of sample and reagent consumption, by coupling nano-LC on-line to a light-emitting diode (LED) based capillary confocal fluorescence detection system capable of on-line BCD with low-flow rates. In this fluorescence detection system, a capillary with an extended light path (bubble cell) was used as a detection cell in order to enhance sensitivity. The technology was applied to a fluorescent enhancement bioassay for the acetylcholine binding protein, a structural analog of the extracellular ligand-binding domain of neuronal nicotinic acetylcholine receptors. In the miniaturized setup, the sensitive and low void volume LED-induced confocal fluorescence detection system operated in flow injection analysis mode allowing the measurement of IC50 values, which were comparable with those measured by a conventional plate reader bioassay. The current setup uses 50 nL as injection volume with a carrier flow rate of 400 nL/min. Finally, coupling of the detection system to gradient reversed-phase nano-LC allowed analysis of mixtures in order to identify the bioactive compounds present by injecting 10 nL of each mixture. Electronic supplementary material The online version of this article (doi:10.1007/s00216-010-4210-x) contains supplementary material, which is available to authorized users. PMID:20872136

  14. Dataflow systems

    SciTech Connect

    Cohen, A.T.

    1982-01-01

    Dataflow languages are stream-oriented and functional, and assume a different operating environment. Programs in these languages are functions which define output as a function of input, with each program being a composition of subfunctions. There is no notion of a global store and, hence, there are no assignment statements. Control flow is determined by the availability of data (function arguments) and need not be explicitly specified by the programmer. The use and development of dataflow languages are motivated by three considerations. They represent parallelism naturally, particularly as it occurs in networks and distributed systems. They readily support very high level programming and their modularity and lack of side-effects makes their programs amenable to analysis. The paper briefly discusses their advantages in each of these three areas. 32 references.

  15. Transfer system

    DOEpatents

    Kurosawa, Kanji; Koga, Bunichiro; Ito, Hideki; Kiriyama, Shigeru; Higuchi, Shizuo

    2003-05-20

    A transport system includes a traveling rail (1) which constitutes a transport route and a transport body (3) which is capable of traveling on the traveling rail in the longitudinal direction of the traveling rail. Flexible drive tubes (5) are arranged on the traveling rail in the longitudinal direction of the traveling rail. The transport body includes a traveling wheel (4) which is capable of rolling on the traveling rail and drive wheels (2) which are capable of rolling on the drive tubes upon receiving the rotational drive power generated by pressure of a pressure medium supplied to the drive tubes while depressing the drive tubes. The traveling rail includes a plurality of transport sections and the transport body is capable of receiving a rotational drive force from the drive tubes at every transport sections. If necessary, a transport route changeover switch which changes over the transport route can be provided between the transport sections.

  16. Systems toxicology.

    PubMed

    Hartung, Thomas; van Vliet, Erwin; Jaworska, Joanna; Bonilla, Leo; Skinner, Nigel; Thomas, Russell

    2012-01-01

    The need for a more mechanistic understanding of the ways in which chemicals modulate biological pathways is urgent if we are to identify and better assess safety issues relating to a wide range of substances developed by the pharmaceutical, chemical, agri-bio, and cosmetic industries. Omics technologies provide a valuable opportunity to refine existing methods and provide information for so-called integrated testing strategies via the creation of signatures of toxicity. By mapping these signatures to underlying pathways of toxicity, some of which have been identified by toxicologists over the last few decades, and bringing them together with pathway information determined from biochemistry and molecular biology, a "systems toxicology" approach will enable virtual experiments to be conducted that can improve the prediction of hazard and the assessment of compound toxicity. PMID:22562485

  17. Intelligent Engine Systems: Bearing System

    NASA Technical Reports Server (NTRS)

    Singh, Arnant P.

    2008-01-01

    The overall requirements necessary for sensing bearing distress and the related criteria to select a particular rotating sensor were established during the phase I. The current phase II efforts performed studies to evaluate the Robustness and Durability Enhancement of the rotating sensors, and to design, and develop the Built-in Telemetry System concepts for an aircraft engine differential sump. A generic test vehicle that can test the proposed bearing diagnostic system was designed, developed, and built. The Timken Company, who also assisted with testing the GE concept of using rotating sensors for the differential bearing diagnostics during previous phase, was selected as a subcontractor to assist General Electric (GE) for the design, and procurement of the test vehicle. A purchase order was prepared to define the different sub-tasks, and deliverables for this task. The University of Akron was selected to provide the necessary support for installing, and integrating the test vehicle with their newly designed test facility capable of simulating the operating environment for the planned testing. The planned testing with good and damaged bearings will be on hold pending further continuation of this effort during next phase.

  18. Separation system

    DOEpatents

    Rubin, Leslie S.

    1986-01-01

    A separation system for dewatering radioactive waste materials includes a disposal container, drive structure for receiving the container, and means for releasably attaching the container to the drive structure. Separation structure disposed in the container adjacent the inner surface of the side wall structure retains solids while allowing passage of liquids. Inlet port structure in the container top wall is normally closed by first valve structure that is centrifugally actuated to open the inlet port and discharge port structure at the container periphery receives liquid that passes through the separation structure and is normally closed by second valve structure that is centrifugally actuated to open the discharge ports. The container also includes coupling structure for releasable engagement with the centrifugal drive structure. Centrifugal force produced when the container is driven in rotation by the drive structure opens the valve structures, and radioactive waste material introduced into the container through the open inlet port is dewatered, and the waste is compacted. The ports are automatically closed by the valves when the container drum is not subjected to centrifugal force such that containment effectiveness is enhanced and exposure of personnel to radioactive materials is minimized.

  19. [Systemic sclerosis].

    PubMed

    Tamborrini, Giorgio; Distler, Meike; Distler, Oliver

    2008-05-01

    Systemic sclerosis (SSc) is a severe fibrotic multiorgan connective tissue disease. Vascular abnormalities such as fingertip ulcers and Raynaud's syndrome as well as involvement of organs including the lungs, heart, kidney and the gastrointestinal tract are prominent features of the disease. There are currently no disease modifying drugs available that can modify the course of the disease. In this review we will discuss medications that have been found to be effective in improving specific organ involvement due to SSc. For the treatment of gastroesophageal reflux disease (GERD), proton pump inhibitors are effective agents. In the setting of clinically significant gastrointestinal dysmotility, metoclopramide, erythromycin and octreotide may be beneficial. Small bowel bacterial overgrowth should be treated with oral antibiotics. Angiotensin converting enzyme inhibitors are the first-line agents for acute renal crisis. A variety of treatment options are available for Raynaud's phenomenon and include calcium channel blockers, iloprost (i. v.), losartan, fluoxetine and sildenafil. Fingertip ulcers can be prevented by using the endothelin receptor antagonist bosentan. The therapeutic options for treatment of pulmonary hypertension associated with SSc include bosentan, sildenafil and various prostacyclin analogs (eg, epoprostenol, treprostinil, iloprost). Sitaxentan, ambrisentan and new phosphodiesterase-5 inhibitors could be new options for therapy as well. Therapeutic options for interstitial lung fibrosis include cyclophosphamide, however, clinical effects are mild to moderate. Methotrexate has been used to treat skin fibrosis and can be beneficial when arthritis is present. PMID:18552072

  20. Incinerator system

    SciTech Connect

    Rathmell, R.K.

    1986-10-07

    An incineration system is described which consists of: combustion chamber structure having an inlet, an outlet, and burner structure in the combustion chamber, heat exchanger structure defining a chamber, divider structure between the heat exchanger chamber and the combustion chamber, an array of tubes extending through the heat exchanger chamber to the inlet of the combustion chamber at the divider structure. The heat exchanger chamber has an inlet coupled to the outlet of the combustion chamber for flow of the combustion products discharged from the combustion chamber through the heat exchanger chamber over the tubes in heat exchange relation, and an outlet for discharge of products from the heat exchanger chamber, aspirator sleeve structure secured to the divider structure between the heat exchanger chamber and the combustion chamber. Each aspirator sleeve receives the outlet end of a heat exchanger tube in slip fit relation so that the heat exchanger tubes are free to thermally expand longitudinally within the aspirator sleeves, and means for flowing vapor through the heat exchanger tubes into the combustion chamber at sufficiently high velocity to produce a reduced pressure effect in the aspirator sleeves in the heat exchanger chamber to draw a minor fraction of combustion products through the aspirator sleeves into the combustion chamber for reincineration.

  1. New Systems Produced by Systemic Change

    ERIC Educational Resources Information Center

    Battino, Wendy; Clem, Jo; Caine, Renate N.; Reigeluth, Charles M.; Chapman, Carrie; Flinders, David J.; Malopinsky, Larissa V.

    2006-01-01

    This article presents new systems produced by systemic change. First is Systemic Changes in the Chugach School District by Wendy Battino and Jo Clem. Second is Systemic Changes in Public Schools through Brain-Based Learning by Renate N. Caine. Third is A Vision of an Information-Age Educational System by Charles M. Reigeluth. Fourth is Systemic…

  2. Hybrid flow system integrating a miniaturized optoelectronic detector for on-line dynamic fractionation and fluorometric determination of bioaccessible orthophosphate in soils.

    PubMed

    Fiedoruk, Marta; Cocovi-Solberg, David J; Tymecki, Łukasz; Koncki, Robert; Miró, Manuel

    2015-02-01

    An integrated Sequential Injection (SI)/Flow Injection (FI) system furnished with a miniaturized LED-based fluorometric detector is presented in this work for expedient bioaccessibility tests of orthophosphate in soils. Equipped with a microcolumn of conical shape containing 50 mg of soil, the hybrid flow system was resorted to on-line dynamic leaching and real-time quantification of pools of mobilizable orthophosphate using a bi-directional syringe pump and multiposition valve. The flexibility of the flow manifold was harnessed to explore both bi-directional and uni-directional flow extraction modes with the added degree of freedom of on-line dilution of extracts whenever needed. Bioaccessible orthophosphate was split in three fractions, the so-called NH4Cl fraction containing labile exchangeable phosphates, the alkaline fraction with Fe and Al-bound phosphates and the acidic fraction containing Ca-bound phosphates. The prevailing molybdenum blue photometric detection method is replaced by spectrofluorometric detection based on the ion pair formation between the phosphomolybdate heteropolyacid and rhodamine B with the subsequent quenching of the dye fluorescence. The dedicated optoelectronic detector was integrated in a secondary FI manifold and operated according to the fluorometric paired emitter-detector diode (FPEDD) principle involving two light emitting diodes as fluorescence inductors and one as detector of LED-induced fluorescence. Demonstrated with the analysis of a standard reference material (SRM 2711) and a real agricultural soil, the developed FI/SI fractionation system with FPEDD detection is proven reliable against the standard molybdenum blue method (p>0.05), and useful for investigation of the leaching kinetics of orthophosphate in bioaccessibility tests through in-line recording of the extraction profiles. PMID:25435227

  3. System safety education focused on system management

    NASA Technical Reports Server (NTRS)

    Grose, V. L.

    1971-01-01

    System safety is defined and characteristics of the system are outlined. Some of the principle characteristics include role of humans in hazard analysis, clear language for input and output, system interdependence, self containment, and parallel analysis of elements.

  4. Distinguishing Systemic from Systematic.

    ERIC Educational Resources Information Center

    Carr, Alison A.

    1996-01-01

    Describes the difference between systemic and systematic as they relate to school reform and instructional design. Highlights include a history of systems theory; systems engineering; instructional systems design; systemic versus reductionist thinking; social systems; and systemic change in education, including power relationships. (LRW)

  5. System design description cone penetrometer system

    SciTech Connect

    Seda, R.Y., Westinghouse Hanford

    1996-08-12

    The system design description documents in detail the design of the cone penetrometer system. The systems includes the cone penetrometer physical package, raman spectroscopy package and moisture sensor package. Information pertinent to the system design, development, fabrication and testing is provided.

  6. Systems view of power systems autonomy

    SciTech Connect

    Anderson, J.L.

    1984-08-01

    A space station will involve the formation and sustained operation of an assembly of humans and machines in space for a period of 10-20 years. Technology and mission studies of a permanently manned, evolutionary space station have identified the need for automated and eventually some degree of autonomous systems operation. A space station power system will have a high degree of interaction with other onboard systems which will act as power loads. By examining the evolution of an operational power system from a systems viewpoint through increasing degrees of automation the system and technology requirements are identified for an evolutionary system.

  7. Networked control of microgrid system of systems

    NASA Astrophysics Data System (ADS)

    Mahmoud, Magdi S.; Rahman, Mohamed Saif Ur; AL-Sunni, Fouad M.

    2016-08-01

    The microgrid has made its mark in distributed generation and has attracted widespread research. However, microgrid is a complex system which needs to be viewed from an intelligent system of systems perspective. In this paper, a network control system of systems is designed for the islanded microgrid system consisting of three distributed generation units as three subsystems supplying a load. The controller stabilises the microgrid system in the presence of communication infractions such as packet dropouts and delays. Simulation results are included to elucidate the effectiveness of the proposed control strategy.

  8. Systems design of long-life systems

    NASA Technical Reports Server (NTRS)

    Miles, R. F., Jr.

    1974-01-01

    A long-life system is defined as a system which cannot be life-tested in its operational environment. Another restriction is that preventive maintenance and repair shall be either impossible or economically disadvantageous. Examples of such systems include planetary spacecraft, communication satellites, undersea telephone cables, and nuclear power plants. The questions discussed are related to the implementation of system functions, approaches to determine the required level of system reliability, and aspects of tradeoffs between requirements and reliability.

  9. Female Reproductive System

    MedlinePlus

    ... How Can I Help a Friend Who Cuts? Female Reproductive System KidsHealth > For Teens > Female Reproductive System Print A ... and female reproductive systems. continue What Is the Female Reproductive System? Most species have two sexes: male and female. ...

  10. Multiple System Atrophy

    MedlinePlus

    ... Enhancing Diversity Find People About NINDS NINDS Multiple System Atrophy Information Page Condensed from Multiple System Atrophy ... Trials Organizations Publicaciones en Español What is Multiple System Atrophy? Multiple system atrophy (MSA) is a progressive ...

  11. System of systems modeling and analysis.

    SciTech Connect

    Campbell, James E.; Anderson, Dennis James; Longsine, Dennis E.; Shirah, Donald N.

    2005-01-01

    This report documents the results of an LDRD program entitled 'System of Systems Modeling and Analysis' that was conducted during FY 2003 and FY 2004. Systems that themselves consist of multiple systems (referred to here as System of Systems or SoS) introduce a level of complexity to systems performance analysis and optimization that is not readily addressable by existing capabilities. The objective of the 'System of Systems Modeling and Analysis' project was to develop an integrated modeling and simulation environment that addresses the complex SoS modeling and analysis needs. The approach to meeting this objective involved two key efforts. First, a static analysis approach, called state modeling, has been developed that is useful for analyzing the average performance of systems over defined use conditions. The state modeling capability supports analysis and optimization of multiple systems and multiple performance measures or measures of effectiveness. The second effort involves time simulation which represents every system in the simulation using an encapsulated state model (State Model Object or SMO). The time simulation can analyze any number of systems including cross-platform dependencies and a detailed treatment of the logistics required to support the systems in a defined mission.

  12. System Software Framework for System of Systems Avionics

    NASA Technical Reports Server (NTRS)

    Ferguson, Roscoe C.; Peterson, Benjamin L; Thompson, Hiram C.

    2005-01-01

    Project Constellation implements NASA's vision for space exploration to expand human presence in our solar system. The engineering focus of this project is developing a system of systems architecture. This architecture allows for the incremental development of the overall program. Systems can be built and connected in a "Lego style" manner to generate configurations supporting various mission objectives. The development of the avionics or control systems of such a massive project will result in concurrent engineering. Also, each system will have software and the need to communicate with other (possibly heterogeneous) systems. Fortunately, this design problem has already been solved during the creation and evolution of systems such as the Internet and the Department of Defense's successful effort to standardize distributed simulation (now IEEE 1516). The solution relies on the use of a standard layered software framework and a communication protocol. A standard framework and communication protocol is suggested for the development and maintenance of Project Constellation systems. The ARINC 653 standard is a great start for such a common software framework. This paper proposes a common system software framework that uses the Real Time Publish/Subscribe protocol for framework-to-framework communication to extend ARINC 653. It is highly recommended that such a framework be established before development. This is important for the success of concurrent engineering. The framework provides an infrastructure for general system services and is designed for flexibility to support a spiral development effort.

  13. Intelligent systems technology infrastructure for integrated systems

    NASA Technical Reports Server (NTRS)

    Lum, Henry, Jr.

    1991-01-01

    Significant advances have occurred during the last decade in intelligent systems technologies (a.k.a. knowledge-based systems, KBS) including research, feasibility demonstrations, and technology implementations in operational environments. Evaluation and simulation data obtained to date in real-time operational environments suggest that cost-effective utilization of intelligent systems technologies can be realized for Automated Rendezvous and Capture applications. The successful implementation of these technologies involve a complex system infrastructure integrating the requirements of transportation, vehicle checkout and health management, and communication systems without compromise to systems reliability and performance. The resources that must be invoked to accomplish these tasks include remote ground operations and control, built-in system fault management and control, and intelligent robotics. To ensure long-term evolution and integration of new validated technologies over the lifetime of the vehicle, system interfaces must also be addressed and integrated into the overall system interface requirements. An approach for defining and evaluating the system infrastructures including the testbed currently being used to support the on-going evaluations for the evolutionary Space Station Freedom Data Management System is presented and discussed. Intelligent system technologies discussed include artificial intelligence (real-time replanning and scheduling), high performance computational elements (parallel processors, photonic processors, and neural networks), real-time fault management and control, and system software development tools for rapid prototyping capabilities.

  14. Type-II InAs/GaSb superlattice LEDs: Applications for infrared scene projector systems

    NASA Astrophysics Data System (ADS)

    Norton, Dennis Thomas, Jr.

    Optoelectronic devices operating in the mid-wave (3-5 mum) and long-wave (8-12 mum) infrared (IR) regions of the electromagnetic spectrum are of a great interest for academic and industrial applications. Due to the lack of atmospheric absorption, devices operating within these spectral bands are particularly useful for spectroscopy, imaging, and dynamic scene projection. Advanced IR imaging systems have created an intense need for laboratory-based infrared scene projector (IRSP) systems which can be used for accurate simulation of real-world phenomena occurring in the IR. These IRSP systems allow for reliable, reproducible, safe, and cost-effective calibration of IR detector arrays. The current state-of-the-art technology utilized for the emitter source of IRSP systems is thermal pixel arrays (TPAs) which are based on thin film resistor technology. Thermal pixel array technology has fundamental limitations related to response time and maximum simulated apparent temperature, making them unsuitable for emulation of very hot (> 700 K) and rapidly evolving scenes. Additionally, there exists a need for dual wavelength emitter arrays for IRSP systems dedicated to calibration of dual wavelength detector arrays. This need is currently met by combining the spectral output from two separate IRSP systems. This configuration requires precise alignment of the output from both systems and results in the maximum radiance being limited to approximately half that of the capability of a given emitter array due to the optics used to combine the outputs. The high switching speed inherent to IR light-emitting diodes (LEDs) and the potential for high power output makes them an appealing candidate to replace the thermal pixel arrays used for IRSP systems. To this end, research has been carried out to develop and improve the device performance of IR LEDs based on InAs/GaSb type-II superlattices (T2SLs). A common method employed to achieve high brightness from LEDs is to incorporate

  15. [X-33 Systems

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Lockheed Martin Skunk Works has compiled an Annual Performance Report of the X-33/RLV Program. This report consists of individual reports from all industry team members, as well as NASA team centers. This portion of the report is comprised of a status report of Allied-Signal Aerospace's contribution to the program. The following is a summary of the work reviewed under their portion of the agreement: (1) Communication Systems; (2) Environmental Control Systems- Active Thermal Control System (ATCS), Purge and Vent System, Hydrogen Detection System (HDS), Avionics Bay Inerting System (ABIS), and Flush Air Data System (FADS); (2) Landing Systems; (3) Power Management and Generation Systems; (4) Flight Control Actuation System (FCAS)- Electric Power Control & Distribution System (EPCDS), and Battery Power System (BPS); and (5) Vehicle Management Systems (VMS)- VMS Hardware, VMS Software Development Activities, and System Integration Laboratory (SIL).

  16. Systems engineering and analysis

    SciTech Connect

    Blanchard, B.S.; Fabrycky, W.J.

    1981-01-01

    An introduction to systems is provided and tools for systems analysis are considered, taking into account system definitions and concepts, approaches for bringing systems into being, models in systems analysis, economic analysis techniques, mathematical modeling and optimization, probability and statistics, queuing theory and analysis, and control concepts and techniques. The system design process is discussed along with the design for operational feasibility, systems engineering management, and system design case studies. Attention is given to conceptual design, preliminary system design, detail design and development, system test and evaluation, design for reliability, design for maintainability, design for supportability, design for economic feasibility, communication system design, finite population system design, energy storage system design, and procurement-inventory system design.

  17. Freedom System Text and Graphics System (TAGS)

    NASA Technical Reports Server (NTRS)

    1989-01-01

    The Text and Graphics System (TAGS) is a high-resolution facsimile system that scans text or graphics material and converts the analog SCAN data into serial digital data. This video shows the TAGS in operation.

  18. Language as a System of Systems

    ERIC Educational Resources Information Center

    Mulder, J. W. F.; Hervey, S. G. J.

    1975-01-01

    Based on Mulder's previous classification of all semiotic systems designed to describe the system of discrete features in human languages, this article explores a further subclassification of the genus language into species. (CLK)

  19. Miniaturised medium pressure capillary liquid chromatography system with flexible open platform design using off-the-shelf microfluidic components.

    PubMed

    Li, Yan; Dvořák, Miloš; Nesterenko, Pavel N; Stanley, Roger; Nuchtavorn, Nantana; Krčmová, Lenka Kujovská; Aufartová, Jana; Macka, Mirek

    2015-10-01

    Trends towards portable analytical instrumentation of the last decades have not been equally reflected in developments of portable liquid chromatography (LC) instrumentation for rapid on-site measurements. A miniaturised medium pressure capillary LC (MPLC) system with gradient elution capability has been designed based on a flexible modular microfluidic system using primarily off-the-shelf low cost components to ensure wide accessibility to other analysts. The microfluidic platform was assembled on a breadboard and contained microsyringe pumps and switch valves, complemented with an injection valve and on-capillary detectors, all controlled by a PC. Four miniaturised microsyringe pumps, with 5, 20 and 100 μL syringe volume options, formed the basis of the pumping system. Two pairs of pumps were used for each mobile phase to create gradient elution capability. The two microsyringe pumps in each pairs were linked by two electrically operated microfluidic switching valves and both pairs of pumps were connected through a zero void volume cross-connector, thus providing a low hold-up volume for gradient formation. Sample was injected by a 20 nL nano-LC sampling valve, directly connected to a 18 cm long 100 μm i.d. Chromolith CapRod RP-18 monolithic capillary column. On-capillary LED-based UV-vis photometric detection was conducted through a piece of equal diameter fused silica capillary connected after the column. The performance of the portable LC system was evaluated theoretically and experimentally, including the maximum operating pressure, gradient mixing performance, and the performance of the detectors. The 5 μL microsyringe pump offered the best performance, with typical maximum operating pressures up to 11.4 ± 0.4 MPa (water) and gradient pumping repeatability of between 4 and 9% for gradients between 0.10% s(-1) and 0.33% s(-1). Test analytes of charged and uncharged dyes and pharmaceuticals of varying hydrophobicity showed typical RSD values of 0

  20. Optical system defect propagation in ABCD systems.

    PubMed

    McKinley, W G; Yura, H T; Hanson, S G

    1988-05-01

    We describe how optical system defects (tilt/jitter, decenter, and despace) propagate through an arbitrary paraxial optical system that can be described by an ABCD ray transfer matrix. A pedagogical example is given that demonstrates the effect of alignment errors on a typical optical system. PMID:19745889

  1. Intelligent tutoring systems for systems engineering methodologies

    NASA Technical Reports Server (NTRS)

    Meyer, Richard J.; Toland, Joel; Decker, Louis

    1991-01-01

    The general goal is to provide the technology required to build systems that can provide intelligent tutoring in IDEF (Integrated Computer Aided Manufacturing Definition Method) modeling. The following subject areas are covered: intelligent tutoring systems for systems analysis methodologies; IDEF tutor architecture and components; developing cognitive skills for IDEF modeling; experimental software; and PC based prototype.

  2. System Design of the SWRL Financial System.

    ERIC Educational Resources Information Center

    Ikeda, Masumi

    To produce various management and accounting reports in order to maintain control of SWRL (Southwest Regional Laboratory) operational and financial activities, a computer-based SWRL financial system was developed. The system design is outlined, and various types of system inputs described. The kinds of management and accounting reports generated…

  3. General Systems Theory and Instructional Systems Design.

    ERIC Educational Resources Information Center

    Salisbury, David F.

    1990-01-01

    Describes basic concepts in the field of general systems theory (GST) and identifies commonalities that exist between GST and instructional systems design (ISD). Models and diagrams that depict system elements in ISD are presented, and two matrices that show how GST has been used in ISD literature are included. (11 references) (LRW)

  4. Lighting system with thermal management system

    SciTech Connect

    Arik, Mehmet; Weaver, Stanton Earl; Stecher, Thomas Elliot; Seeley, Charles Erklin; Kuenzler, Glenn Howard; Wolfe, Jr., Charles Franklin; Utturkar, Yogen Vishwas; Sharma, Rajdeep; Prabhakaran, Satish; Icoz, Tunc

    2015-08-25

    Lighting systems having unique configurations are provided. For instance, the lighting system may include a light source, a thermal management system and driver electronics, each contained within a housing structure. The light source is configured to provide illumination visible through an opening in the housing structure. The thermal management system is configured to provide an air flow, such as a unidirectional air flow, through the housing structure in order to cool the light source. The driver electronics are configured to provide power to each of the light source and the thermal management system.

  5. Lighting system with thermal management system

    DOEpatents

    Arik, Mehmet; Weaver, Stanton; Stecher, Thomas; Seeley, Charles; Kuenzler, Glenn; Wolfe, Jr., Charles; Utturkar, Yogen; Sharma, Rajdeep; Prabhakaran, Satish; Icoz, Tunc

    2013-05-07

    Lighting systems having unique configurations are provided. For instance, the lighting system may include a light source, a thermal management system and driver electronics, each contained within a housing structure. The light source is configured to provide illumination visible through an opening in the housing structure. The thermal management system is configured to provide an air flow, such as a unidirectional air flow, through the housing structure in order to cool the light source. The driver electronics are configured to provide power to each of the light source and the thermal management system.

  6. Lighting system with thermal management system

    DOEpatents

    Arik, Mehmet; Weaver, Stanton Earl; Stecher, Thomas Elliot; Seeley, Charles Erklin; Kuenzler, Glenn Howard; Wolfe, Jr., Charles Franklin; Utturkar, Yogen Vishwas; Sharma, Rajdeep; Prabhakaran, Satish; Icoz, Tunc

    2015-02-24

    Lighting systems having unique configurations are provided. For instance, the lighting system may include a light source, a thermal management system and driver electronics, each contained within a housing structure. The light source is configured to provide illumination visible through an opening in the housing structure. The thermal management system is configured to provide an air flow, such as a unidirectional air flow, through the housing structure in order to cool the light source. The driver electronics are configured to provide power to each of the light source and the thermal management system.

  7. DDL system: Design systhesis of digital systems

    NASA Technical Reports Server (NTRS)

    Shiva, S. G.

    1983-01-01

    Digital Systems Design Language was integrated into the CADAT system environment of NASA-MSFC. The major technical aspects of this integration are summarized. Automatic hardware synthesis is now possible starting with a high level description of the system to be synthesized. The DDL system provides a high level design verification capability, thereby minimizing design changes in the later stages of the design cycle. An overview of the DDL system covering the translation, simulation and synthesis capabilities is provided. Two companion documents (the user's and programmer's manuals) are to be consulted for detailed discussions.

  8. Microwave landing system autoland system analysis

    NASA Technical Reports Server (NTRS)

    Feather, J. B.; Craven, B. K.

    1991-01-01

    The objective was to investigate the ability of present day aircraft equipped with automatic flight control systems to fly advanced Microwave Landing Systems (MLS) approaches. The tactical approach used to achieve this objective included reviewing the design and autoland operation of the MD-80 aircraft, simulating the MLS approaches using a batch computer program, and assessing the performance of the autoland system from computer generated data. The results showed changes were required to present Instrument Landing System (ILS) procedures to accommodate the new MLS curved paths. It was also shown that in some cases, changes to the digital flight guidance systems would be required so that an autoland could be performed.

  9. Collaborative Systems Testing

    ERIC Educational Resources Information Center

    Pocatilu, Paul; Ciurea, Cristian

    2009-01-01

    Collaborative systems are widely used today in various activity fields. Their complexity is high and the development involves numerous resources and costs. Testing collaborative systems has a very important role for the systems' success. In this paper we present taxonomy of collaborative systems. The collaborative systems are classified in many…

  10. Energy Systems Design

    NASA Technical Reports Server (NTRS)

    1986-01-01

    PRESTO, a COSMIC program, handles energy system specifications and predicts design efficiency of cogeneration systems. These systems allow a company to use excess energy produced to generate electricity. PRESTO is utilized by the Energy Systems Division of Thermo Electron Corporation in the custom design of cogeneration systems.