Science.gov

Sample records for study utilizing optical

  1. Determination of feasibility and utility of microscope-integrated optical coherence tomography during ophthalmic surgery: the DISCOVER Study RESCAN Results.

    PubMed

    Ehlers, Justis P; Goshe, Jeff; Dupps, William J; Kaiser, Peter K; Singh, Rishi P; Gans, Richard; Eisengart, Jonathan; Srivastava, Sunil K

    2015-10-01

    Optical coherence tomography (OCT) has transformed the clinical management of a myriad of ophthalmic conditions. Applying OCT to ophthalmic surgery may have implications for surgical decision making and patient outcomes. To assess the feasibility and effect on surgical decision making of a microscope-integrated intraoperative OCT (iOCT) system. Report highlighting the 1-year results (March 2014-February 2015) of the RESCAN 700 portion of the DISCOVER (Determination of Feasibility of Intraoperative Spectral Domain Microscope Combined/Integrated OCT Visualization During En Face Retinal and Ophthalmic Surgery) study, a single-site, multisurgeon, prospective consecutive case series regarding this investigational device. Participants included patients undergoing ophthalmic surgery. Data on clinical characteristics were collected, and iOCT was performed during surgical milestones, as directed by the operating surgeon. A surgeon questionnaire was issued to each surgeon and was completed after each case to evaluate the role of iOCT during surgery and its particular role in select surgical procedures. Percentage of cases with successful acquisition of iOCT (ie, feasibility). Percentage of cases in which iOCT altered surgical decision making (ie, utility). During year 1 of the DISCOVER study, a total of 227 eyes (91 anterior segment cases and 136 posterior segment cases) underwent imaging with the RESCAN 700 system. Successful imaging (eg, the ability to acquire an OCT image of the tissue of interest) was obtained for 224 of 227 eyes (99% [95% CI, 98%-100%]). During lamellar keratoplasty, the iOCT data provided information that altered the surgeon's decision making in 38% of the cases (eg, complete graft apposition when the surgeon believed there was interface fluid). In membrane peeling procedures, iOCT information was discordant with the surgeon's impression of membrane peel completeness in 19% of cases (eg, lack of residual membrane or presence of occult membrane), thus

  2. Focal Plane Alignment Utilizing Optical CMM

    NASA Technical Reports Server (NTRS)

    Liebe, Carl Christian; Meras, Patrick L.; Clark, Gerald J.; Sedaka, Jack J.; Kaluzny, Joel V.; Hirsch, Brian; Decker, Todd A.; Scholtz, Christopher R.

    2012-01-01

    In many applications, an optical detector has to be located relative to mechanical reference points. One solution is to specify stringent requirements on (1) mounting the optical detector relative to the chip carrier, (2) soldering the chip carrier onto the printed circuit board (PCB), and (3) installing the PCB to the mechanical structure of the subsystem. Figure 1 shows a sketch of an optical detector mounted relative to mechanical reference with high positional accuracy. The optical detector is typically a fragile wafer that cannot be physically touched by any measurement tool. An optical coordinate measuring machine (CMM) can be used to position optical detectors relative to mechanical reference points. This approach will eliminate all requirements on positional tolerances. The only requirement is that the PCB is manufactured with oversized holes. An exaggerated sketch of this situation is shown in Figure 2. The sketch shows very loose tolerances on mounting the optical detector in the chip carrier, loose tolerance on soldering the chip carrier to the PCB, and finally large tolerance on where the mounting screws are located. The PCB is held with large screws and oversized holes. The PCB is mounted loosely so it can move freely around. The optical CMM measures the mechanical reference points. Based on these measurements, the required positions of the optical detector corners can be calculated. The optical CMM is commanded to go to the position where one detector corner is supposed to be. This is indicated with the cross-hairs in Figure 2(a). This figure is representative of the image of the optical CMM monitor. Using a suitable tapping tool, the PCB is manually tapped around until the corner of the optical detector is at the crosshairs of the optical CMM. The CMM is commanded to another corner, and the process is repeated a number of times until all corners of the optical detector are within a distance of 10 to 30 microns of the required position. The situation

  3. Space platform utilities distribution study

    NASA Technical Reports Server (NTRS)

    Lefever, A. E.

    1980-01-01

    Generic concepts for the installation of power data and thermal fluid distribution lines on large space platforms were discussed. Connections with central utility subsystem modules and pallet interfaces were also considered. Three system concept study platforms were used as basepoints for the detail development. The tradeoff of high voltage low voltage power distribution and the impact of fiber optics as a data distribution mechanism were analyzed. Thermal expansion and temperature control of utility lines and ducts were considered. Technology developments required for implementation of the generic distribution concepts were identified.

  4. Deflection Sensors Utilizing Optical Multi-Stability

    NASA Astrophysics Data System (ADS)

    Shehadeh, Shadi H.; Cada, Michael; Qasymeh, Montasir; Ma, Yuan

    2010-06-01

    Deflection sensors have attracted significant attention due to their wide application in pressure and temperature measurements in practical systems. Several techniques have been proposed, studied, and tested to realize optical deflection sensor elements, including Mach-Zehnder (MZI), and Fabry-Pérot interferometers. In this work, a novel optical deflection sensor that is comprised of two cascaded optical resonators is proposed and analyzed. The proposed structure is designed to operate in the multi-stable (input to output) regime. As the first resonator is equipped with a movable mirror, which is connected to a diaphragm in order to sense changes in deflection, the second resonator is filled with non-linear material. It is demonstrated that such a structure has a novel memory property, aside from having the ability to yield instant deflection measurements. This novel property is attributed to the non-linear refractive index of the medium of the second resonator. Furthermore, the sensor sensitivity (which is the ratio of the change in the output light intensity to the change in the induced deflection) is enhanced due to the input-output multi-stable behavior of the proposed structure. This device possesses a promising potential for applications in future smart sensors.

  5. A Space-Based Optical Communication System Utilizing Fiber Optics

    DTIC Science & Technology

    1989-11-09

    free-space optical communication systems are not widely recognized. The current generation of spaceborne optical communication systems relies on the...Preliminary experimental results of our breadboard fiber-based coherent optical communication system are also presented.

  6. Compact optical encoder approach utilizing novel diffractive optics design

    NASA Astrophysics Data System (ADS)

    DeVoe, Catherine E.; Horwitz, Bruce A.; Johnson, Eric G.; Fedor, Adam S.

    1998-04-01

    Diffractive optical encoders have quickly established themselves in the marketplace because of their small seize, high accuracy and relaxed alignment tolerances, but current products are still composed of carefully packages, discrete optical and electro-optical components. MicroE and Digital Optics Corporation have been working together on the next generation of these encoders, which replaces all discrete and refractive elements with DOE's and more completely integrates the requisite optical and electro-optical components. In this paper we describe a monolithic source/optics/detector encoder module we have designed and prototyped for a satellite application under a NASA Phase I SBIR contract.

  7. Tribal Utility Feasibility Study

    SciTech Connect

    Engel, R. A.; Zoellick, J. J.

    2007-06-30

    The Schatz Energy Research Center (SERC) assisted the Yurok Tribe in investigating the feasibility of creating a permanent energy services program for the Tribe. The original purpose of the DOE grant that funded this project was to determine the feasibility of creating a full-blown Yurok Tribal electric utility to buy and sell electric power and own and maintain all electric power infrastructure on the Reservation. The original project consultant found this opportunity to be infeasible for the Tribe. When SERC took over as project consultant, we took a different approach. We explored opportunities for the Tribe to develop its own renewable energy resources for use on the Reservation and/or off-Reservation sales as a means of generating revenue for the Tribe. We also looked at ways the Tribe can provide energy services to its members and how to fund such efforts. We identified opportunities for the development of renewable energy resources and energy services on the Yurok Reservation that fall into five basic categories: • Demand-side management – This refers to efforts to reduce energy use through energy efficiency and conservation measures. • Off-grid, facility and household scale renewable energy systems – These systems can provide electricity to individual homes and Tribal facilities in areas of the Reservation that do not currently have access to the electric utility grid. • Village scale, micro-grid renewable energy systems - These are larger scale systems that can provide electricity to interconnected groups of homes and Tribal facilities in areas of the Reservation that do not have access to the conventional electric grid. This will require the development of miniature electric grids to serve these interconnected facilities. • Medium to large scale renewable energy development for sale to the grid – In areas where viable renewable energy resources exist and there is access to the conventional electric utility grid, these resources can be

  8. Advanced Imaging Optics Utilizing Wavefront Coding.

    SciTech Connect

    Scrymgeour, David; Boye, Robert; Adelsberger, Kathleen

    2015-06-01

    Image processing offers a potential to simplify an optical system by shifting some of the imaging burden from lenses to the more cost effective electronics. Wavefront coding using a cubic phase plate combined with image processing can extend the system's depth of focus, reducing many of the focus-related aberrations as well as material related chromatic aberrations. However, the optimal design process and physical limitations of wavefront coding systems with respect to first-order optical parameters and noise are not well documented. We examined image quality of simulated and experimental wavefront coded images before and after reconstruction in the presence of noise. Challenges in the implementation of cubic phase in an optical system are discussed. In particular, we found that limitations must be placed on system noise, aperture, field of view and bandwidth to develop a robust wavefront coded system.

  9. Scheme for Terminal Guidance Utilizing Acousto-Optic Correlator.

    DTIC Science & Technology

    longitudinally extending acousto - optic device as index of refraction variation pattern signals. Real time signals corresponding to the scene actually being viewed...by the vehicle are propagated across the stored signals, and the results of an acousto - optic correlation are utilized to determine X and Y error

  10. Free space optical communications utilizing MEMS adaptive optics correction

    NASA Astrophysics Data System (ADS)

    Thompson, Charles A.; Kartz, Michael W.; Flath, Laurence M.; Wilks, Scott C.; Young, Richard A.; Johnson, Gary W.; Ruggiero, Anthony J.

    2002-12-01

    Free space optical communications (FSO) are beginning to provide attractive alternatives to fiber-based solutions in many situations. Currently, a handful of companies provide fiberless alternatives especially aimed at corporate intranet and sporting event video. These solutions are geared toward solving the 'last mile' connectivity issues. There exists a potential need to extend this pathlength to distances much greater than a 1 km, particularly for government and military applications. For cases of long distance optical propagation, atmospheric turbulence will ultimately limit the maximum achievable data rate. In this paper, we propose a method of improved signal quality through the use of adaptive optics. In particular, we show work in progress toward a high-speed, small footprint Adaptive Optics system for horizontal and slant path laser communications. Such a system relies heavily on recent progress in Micro-Electro-Mechanical Systems (MEMS) deformable mirrors as well as improved communication and computational components.

  11. Free Space Optical Communications Utilizing MEMS Adaptive Optics Correction

    SciTech Connect

    Thompson, C A; Kartz, M W; Flath, L M; Wilks, S C; Young, R A; Johnson, G W; Ruggiero, A J

    2002-07-09

    Free space optical communications (FSO) are beginning to provide attractive alternatives to fiber-based solutions in many situations. Currently, a handful of companies provide fiberless alternatives specifically aimed at corporate intranet and sporting event video applications. These solutions are geared toward solving the ''last mile'' connectivity issues. There exists a potential need to extend this pathlength to distances much greater than a 1 km, particularly for government and military applications. For cases of long distance optical propagation, atmospheric turbulence will ultimately limit the maximum achievable data rate. In this paper, we propose a method to improve signal quality through the use of adaptive optics. In particular, we show work in progress toward a high-speed, small footprint Adaptive Optics system for horizontal and slant path laser communications. Such a system relies heavily on recent progress in Micro-Electro-Mechanical Systems (MEMS) deformable mirrors, as well as improved communication and computational components.

  12. Demonstration of optical interference filters utilizing tunable refractive index layers.

    PubMed

    Poxson, David J; Mont, Frank W; Schubert, Martin F; Kim, Jong Kyu; Cho, Jaehee; Schubert, E Fred

    2010-11-08

    Optical interference filters utilizing tunable refractive index layers are shown to have higher spectral fidelity as compared to conventional filters consisting of non-tunable refractive index layers. To demonstrate this increase in spectral fidelity, we design and compare a variety of optical interference filters employing both tunable and non-tunable refractive index layers. Additionally, a five-layer optical interference filter utilizing tunable refractive index layers is designed and fabricated for use with a Xenon lamp to replicate the Air Mass 0 solar irradiance spectrum and is shown to have excellent spectral fidelity.

  13. Integrated optics technology study

    NASA Technical Reports Server (NTRS)

    Chen, B.

    1982-01-01

    The materials and processes available for the fabrication of single mode integrated electrooptical components are described. Issues included in the study are: (1) host material and orientation, (2) waveguide formation, (3) optical loss mechanisms, (4) wavelength selection, (5) polarization effects and control, (6) laser to integrated optics coupling,(7) fiber optic waveguides to integrated optics coupling, (8) souces, (9) detectors. The best materials, technology and processes for fabrication of integrated optical components for communications and fiber gyro applications are recommended.

  14. Utilization of Infrared Fiber Optic in the Automotive Industry

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S.; Brantley, Lott W. (Technical Monitor)

    2001-01-01

    Fiber optics are finding a place in the automotive industry. Illumination is the primary application today. Soon, however, fiber optics will be used for data communications and sensing applications. Silica fiber optics and plastic fibers are sufficient for illumination and communication applications however, sensing applications involving high temperature measurement and remote gas analysis would benefit from the use of infrared fiber optics. Chalcogonide and heavy metal fluoride glass optical fibers are two good candidates for these applications. Heavy metal fluoride optical fibers are being investigated by NASA for applications requiring transmission in the infrared portion of the electromagnetic spectrum. Zirconium-Barium-Lanthanum-Aluminum-Sodium-Fluoride (ZBLAN) is one such material which has been investigated. This material has a theoretical attenuation coefficient 100 times lower than that of silica and transmits into the mid-IR. However, the measured attenuation coefficient is higher than silica due to impurities and crystallization. Impurities can be taken care of by utilizing cleaner experimental protocol. It has been found that crystallization can be suppressed by processing in reduced gravity. Fibers processed in reduced gravity on the KC135 reduced gravity aircraft were found to be free of crystals while those processed on the ground were found to have crystals. These results will be presented along with plans for producing continuous lengths of ZBLAN optical fiber on board the International Space Station.

  15. Utilization of Infrared Fiber Optic in the Automotive Industry

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S.; Brantley, Lott W. (Technical Monitor)

    2001-01-01

    Fiber optics are finding a place in the automotive industry. Illumination is the primary application today. Soon, however, fiber optics will be used for data communications and sensing applications. Silica fiber optics and plastic fibers are sufficient for illumination and communication applications however, sensing applications involving high temperature measurement and remote gas analysis would benefit from the use of infrared fiber optics. Chalcogonide and heavy metal fluoride glass optical fibers are two good candidates for these applications. Heavy metal fluoride optical fibers are being investigated by NASA for applications requiring transmission in the infrared portion of the electromagnetic spectrum. Zirconium-Barium-Lanthanum-Aluminum-Sodium-Fluoride (ZBLAN) is one such material which has been investigated. This material has a theoretical attenuation coefficient 100 times lower than that of silica and transmits into the mid-IR. However, the measured attenuation coefficient is higher than silica due to impurities and crystallization. Impurities can be taken care of by utilizing cleaner experimental protocol. It has been found that crystallization can be suppressed by processing in reduced gravity. Fibers processed in reduced gravity on the KC135 reduced gravity aircraft were found to be free of crystals while those processed on the ground were found to have crystals. These results will be presented along with plans for producing continuous lengths of ZBLAN optical fiber on board the International Space Station.

  16. Administrative Utility Analysis: Study Summary.

    ERIC Educational Resources Information Center

    Peat, Marwick, Mitchell and Co., San Juan, Puerto Rico.

    This document summarizes the recommendations made as a result of a study on administrative utility analysis and vocational education programs for Puerto Rico. The major recommendation was that the Area of Vocational and Technical Education (AVTE) in the Puerto Rico Department of Education be restructured at the central organizational level, for…

  17. Quantum communication network utilizing quadripartite entangled states of optical field

    SciTech Connect

    Shen Heng; Su Xiaolong; Jia Xiaojun; Xie Changde

    2009-10-15

    We propose two types of quantum dense coding communication networks with optical continuous variables, in which a quadripartite entangled state of the optical field with totally three-party correlations of quadrature amplitudes is utilized. In the networks, the exchange of information between any two participants can be manipulated by one or two of the remaining participants. The channel capacities for a variety of communication protocols are numerically calculated. Due to the fact that the quadripartite entangled states applied in the communication systems have been successfully prepared already in the laboratory, the proposed schemes are experimentally accessible at present.

  18. ELECTRO-OPTIC PROJECTOR STUDY.

    DTIC Science & Technology

    The report describes research and development tasks undertaken in the development of a Pockels Effect electro - optic light valve. Two reflex...lens electron optics are used in different configurations. The electro - optic crystal utilized was KD2PO4 and when operated in a reflex mode provides

  19. Compact carbon monoxide sensor utilizing a confocal optical cavity.

    NASA Technical Reports Server (NTRS)

    Scott, B.; Magyar, J.; Weyant, R.; Hall, J.

    1973-01-01

    The carbon monoxide sensor discussed in this paper utilizes a unique confocal cavity which allows the complete system to be packaged in a small volume suitable for hand-held use. The optical system is the heart of the instrument with equal emphasis placed on the electronics support circuitry, consisting essentially of a thermal infrared pyroelectric detector and lock-in amplifier. The pyroelectric detector offers a major advantage over other thermal detectors, providing a signal-to-noise ratio and detectivity that remain nearly constant over the frequency range from dc to 2000 Hz. Since bias voltage is not required, low frequency noise is not generated in the detector.

  20. Compact carbon monoxide sensor utilizing a confocal optical cavity.

    NASA Technical Reports Server (NTRS)

    Scott, B.; Magyar, J.; Weyant, R.; Hall, J.

    1973-01-01

    The carbon monoxide sensor discussed in this paper utilizes a unique confocal cavity which allows the complete system to be packaged in a small volume suitable for hand-held use. The optical system is the heart of the instrument with equal emphasis placed on the electronics support circuitry, consisting essentially of a thermal infrared pyroelectric detector and lock-in amplifier. The pyroelectric detector offers a major advantage over other thermal detectors, providing a signal-to-noise ratio and detectivity that remain nearly constant over the frequency range from dc to 2000 Hz. Since bias voltage is not required, low frequency noise is not generated in the detector.

  1. Clinical Utility of Optical Coherence Tomography in Glaucoma

    PubMed Central

    Dong, Zachary M.; Wollstein, Gadi; Schuman, Joel S.

    2016-01-01

    Optical coherence tomography (OCT) has established itself as the dominant imaging modality in the management of glaucoma and retinal diseases, providing high-resolution visualization of ocular microstructures and objective quantification of tissue thickness and change. This article reviews the history of OCT imaging with a specific focus on glaucoma. We examine the clinical utility of OCT with respect to diagnosis and progression monitoring, with additional emphasis on advances in OCT technology that continue to facilitate glaucoma research and inform clinical management strategies. PMID:27537415

  2. Utility robotic planning: case studies

    SciTech Connect

    Roman, H.T.; Travato, S.A.; Irving, T.L.; Patnaude, L.G.

    1986-03-01

    Currently, the utility use of robotic devices is most appropriate in nuclear power plants. Four utilities are currently approaching the task of robotic applications. The planning program of each of the utilities is discussed. The following similarities of approach are noted: Plant operating personnel are surveyed for application ideas, and a company task force is established involving these personnel to determine specific application needs and cost-benefit. The state-of-the-art of various robotic devices is evaluated and selected equipment is tested in existing plants. The robotic experience gained from nuclear plant applications is extended to other non-nuclear areas. 2 figures, 1 table.

  3. Utilizing nonlinear optical properties of nanoparticles for imaging and sensing

    NASA Astrophysics Data System (ADS)

    Yust, Brian G.; Razavi, Neema; Pedraza, Francisco; Sardar, Dhiraj K.

    2012-03-01

    Nonlinear optical properties of barium titanate (BaTiO3) nanoparticles are investigated as a function of size and shape. BaTiO3 is an attractive option as a nonlinear material because it can exhibit a high second and third order electronic susceptibility even at the nanoscale. These particles are employed as contrast agents/biomarkers and phase conjugate nanomirrors in imaging, utilizing second harmonic generation for two-photon microscopy and four-wave mixing for three-photon microscopy and scattering reversal image enhancement. Silver is also used to create a shell around the BaTiO3 nanoparticle to see if a core/shell structure enhances any of the nonlinear effects.

  4. Integrated optics technology study

    NASA Technical Reports Server (NTRS)

    Chen, B.; Findakly, T.; Innarella, R.

    1982-01-01

    The status and near term potential of materials and processes available for the fabrication of single mode integrated electro-optical components are discussed. Issues discussed are host material and orientation, waveguide formation, optical loss mechanisms, wavelength selection, polarization effects and control, laser to integrated optics coupling fiber optic waveguides to integrated optics coupling, sources, and detectors. Recommendations of the best materials, technology, and processes for fabrication of integrated optical components for communications and fiber gyro applications are given.

  5. Optical signature utilization of remote sensing of nearshore waters

    SciTech Connect

    Bagheri, S.; Dios, R.A.; Pan, Zhengxiang

    1997-08-01

    Existing satellite sensors lack the spectral capabilities to discriminate phytoplankton pigments in water bodies. New satellite sensors (EOS planned for 1998 and SeaWIFS forthcoming) with narrow bandwidths can provide detailed spectral resolution necessary to distinguish optical properties of nearshore waters provided calibrated seatruth data are available. This will facilitate utility of spaceborne water color sensors for discrimination of bloom forming phytoplankton species and support oceanographic/coastal zone remote sensing missions of NASA, Navy and other agencies. The objective of the research was to develop a library of absorption spectra for the most common phytoplankton found locally within the Hudson/Raritan Estuary. Both culture grown and field samples of phytoplankton were concentrated and analyzed using standard techniques. Chlorophyll-a and phaeopigment concentrations were determined based on spectrometric analysis, producing characteristic absorption spectra. To further refine and discriminate pigment compositions which affect remote color sensing recorded by sensors, spectral derivative and polynomial regression analysis were applied to the absorption spectra. Using these models, it was possible to identify optimum wavelengths characterizing pigment compositions of phytoplankton species in the estuary. Future work will integrate the spectral library into GenIsis--hyperspectral image processing to establish correlation with remotely sensed data.

  6. State Network Utilization Study: Mississippi Educational Television.

    ERIC Educational Resources Information Center

    Wilson, Savan; And Others

    This document is the result of a utilization study of Mississippi Educational Television where 27 target audiences were identified and surveyed. The following information is included: a draft of and updated state network utilization studies; planning and management strategies; a profile of the survey populations; a distance learning survey report;…

  7. PHOTOLYSIS STUDIES UTILIZING RADIOACTIVE TRACERS.

    DTIC Science & Technology

    PHOTOLYSIS, *TRACER STUDIES), (* TRITIATED COMPOUNDS, PHOTOLYSIS), (*GAS CHROMATOGRAPHY, LABELED SUBSTANCES), ALKENES, KETENES, TRITIUM, ATOMIC ENERGY LEVELS, ALKANES, METHANE , ISOTOPES, ETHYLENES, MOLECULAR ORBITALS

  8. Electro-Optical Laser Technology. Curriculum Utilization. Final Report.

    ERIC Educational Resources Information Center

    Nawn, John H.

    This report describes a program to prepare students for employment as laser technicians and laser operators and to ensure that they have the necessary skills required by the industry. The objectives are to prepare a curriculum and syllabus for an associate degree program in Electro-Optical Laser Technology. The 2-year Electro-Optical Laser program…

  9. Optical data processing study

    NASA Technical Reports Server (NTRS)

    Pinson, L. J.

    1976-01-01

    An onboard coherent optical data processing system was designed to handle large information content of imagery at high speeds, reduce redundancy in picture transmission, and detect specific image features. Theoretically derived Fourier transform characteristics for simple but representative two dimensional images served as a basis for predicting expected features of actual target images. Fourier transformation and spatial filtering of coherent optical images was accomplished theoretically and in the laboratory. The effect of various parameters such as optical aperature, incidence angles, the transparency assumption, the thin lens approximation on resolution, and performance of the system are predicted and tested.

  10. Extreme prepulse contrast utilizing cascaded-optical parametric amplification

    SciTech Connect

    Jovanovic, I; Haefner, C; Wattellier, B; Barty, C J

    2006-06-15

    It has been shown recently that an optical parametric chirped-pulse amplifier can be easily reconfigured into a cascaded-optical parametric amplifier (COPA), enabling complete prepulse removal and optical switching with a window defined by the pump pulse duration. We have demonstrated instrument-limited measurement of the COPA prepulse contrast >1.4 x 10{sup 11} using 30-mJ pulses. The COPA technique is applicable to all energy ranges and pulse durations. A convenient millijoule-scale implementation of this technique is presented using a single, large-aspect-ratio quasi-phase-matched nonlinear crystal.

  11. Soot Optical Property Study

    NASA Technical Reports Server (NTRS)

    Aung, K. T.; Hassan, M. I.; Krishnan, S. S.; Lin, K.-C.; Xu, F.; Faeth, G. M.; Urban, D. L. (Technical Monitor); Yuan, Z.-G. (Technical Monitor)

    2001-01-01

    Recent past studies of soot reaction processes in laminar premixed and nonpremixed flames generally have used the intrusive technique of thermophoretic sampling and analysis by transmission electron microscopy (TEM) to observe soot structure and obtain important fundamental information about soot particle properties, such as soot primary particle diameters, the rate of change of soot primary particle diameter as a function of time (or rate of soot surface growth or oxidation), the amount of soot particle reactive surface area per unit volume, the number of primary soot particles per unit volume, and the rate of formation of primary soot particles (or the rate of soot primary particle nucleation). Given the soot volume per unit volume of the flame (or the soot volume fraction), all these properties are readily found from a measurement of the soot primary particle diameter (which usually is nearly a constant for each location within a laminar flame). This approach is not possible within freely propagating flames, however, because soot properties at given positions in such flames vary relatively rapidly as a function of time in the soot formation and oxidation regions compared to the relatively lengthy sampling times needed to accumulate adequate soot samples and to minimize effects of soot collected on the sampling grid as it moves to and from the sampling position through other portions of the flame. Thus, nonintrusive optical methods must be used to find the soot primary particle diameters needed to define the soot surface reaction properties mentioned earlier. Unfortunately, approximate nonintrusive methods used during early studies of soot reaction properties in flames, found from laser scattering and absorption measurements analyzed assuming either Rayleigh scattering or Mie scattering from polydisperse effective soot particles having the same mass of soot as individual soot aggregates, have not been found to be an effective way to estimate the soot surface

  12. Optical adhesive property study

    SciTech Connect

    Sundvold, P.D.

    1996-01-01

    Tests were performed to characterize the mechanical and thermal properties of selected optical adhesives to identify the most likely candidate which could survive the operating environment of the Direct Optical Initiation (DOI) program. The DOI system consists of a high power laser and an optical module used to split the beam into a number of channels to initiate the system. The DOI requirements are for a high shock environment which current military optical systems do not operate. Five candidate adhesives were selected and evaluated using standardized test methods to determine the adhesives` physical properties. EC2216, manufactured by 3M, was selected as the baseline candidate adhesive based on the test results of the physical properties.

  13. Utilizing Data from Cancer Patient & Survivor Studies

    Cancer.gov

    Utilizing Data from Cancer Patient & Survivor Studies and Understanding the Current State of Knowledge and Developing Future Research Priorities, a 2011 workshop sponsored by the Epidemiology and Genomics Research Program.

  14. Utility of Digital Stereo Images for Optic Disc Evaluation

    PubMed Central

    Ying, Gui-shuang; Pearson, Denise J.; Bansal, Mayank; Puri, Manika; Miller, Eydie; Alexander, Judith; Piltz-Seymour, Jody; Nyberg, William; Maguire, Maureen G.; Eledath, Jayan; Sawhney, Harpreet

    2010-01-01

    Purpose. To assess the suitability of digital stereo images for optic disc evaluations in glaucoma. Methods. Stereo color optic disc images in both digital and 35-mm slide film formats were acquired contemporaneously from 29 subjects with various cup-to-disc ratios (range, 0.26–0.76; median, 0.475). Using a grading scale designed to assess image quality, the ease of visualizing optic disc features important for glaucoma diagnosis, and the comparative diameters of the optic disc cup, experienced observers separately compared the primary digital stereo images to each subject's 35-mm slides, to scanned images of the same 35-mm slides, and to grayscale conversions of the digital images. Statistical analysis accounted for multiple gradings and comparisons and also assessed image formats under monoscopic viewing. Results. Overall, the quality of primary digital color images was judged superior to that of 35-mm slides (P < 0.001), including improved stereo (P < 0.001), but the primary digital color images were mostly equivalent to the scanned digitized images of the same slides. Color seemingly added little to grayscale optic disc images, except that peripapillary atrophy was best seen in color (P < 0.0001); both the nerve fiber layer (P < 0.0001) and the paths of blood vessels on the optic disc (P < 0.0001) were best seen in grayscale. The preference for digital over film images was maintained under monoscopic viewing conditions. Conclusions. Digital stereo optic disc images are useful for evaluating the optic disc in glaucoma and allow the application of advanced image processing applications. Grayscale images, by providing luminance distinct from color, may be informative for assessing certain features. PMID:20505199

  15. North Carolina harvest and utilization study, 2002

    Treesearch

    James W. Bentley; Tony G. Johnson

    2006-01-01

    In 2002, a harvest and utilization study was conducted on 108 operations throughout North Carolina. There were 2,926 total trees measured; 1,693, or 58 percent, were softwood, while 1,233, or 42 percent, were hardwood. Results from this study showed that 86 percent of the total softwood volume measured was utilized for a product, and 14 percent was left as logging...

  16. South Carolina harvest and utilization study, 2011

    Treesearch

    Kerry J.W. Dooley; Jason A. Cooper; James W. Bentley

    2015-01-01

    In 2011, a harvest and utilization study was conducted on 80 operations throughout South Carolina. There were 1,974 total trees measured; 1,317 or 67 percent were softwood, while 657 or 33 percent were hardwood. Results from this study showed that 86 percent of the total softwood volume measured was utilized for a product, and 14 percent was left as logging residue....

  17. Georgia harvest and utilization study, 2009

    Treesearch

    James W. Bentley

    2011-01-01

    In 2009, a harvest and utilization study was conducted on 80 operations throughout Georgia. There were 1,981 total trees measured: 1,453 or 73 percent were softwood, while 528 or 27 percent were hardwood. Results from this study showed that 88 percent of the total softwood volume measured was utilized for a product, and 12 percent was left as logging residue. Seventy-...

  18. South Carolina harvest and utilization study, 2006

    Treesearch

    James W. Bentley; Tony G. Johnson

    2008-01-01

    In 2006, a harvest and utilization study was conducted on 99 operations throughout South Carolina. There were 2,904 total trees measured; 1,763 or 61 percent were softwood, while 1,141 or 39 percent were hardwood. Results from this study showed that 87 percent of the total softwood volume measured was utilized for a product, and 13 percent was left as logging residue....

  19. Kentucky harvest and utilization study, 2007

    Treesearch

    Jason A. Cooper; James W. Bentley

    2013-01-01

    In 2007, a harvest and utilization study was conducted on 53 operations in Kentucky. There were 1,310 total trees measured: 263 or 20 percent were softwood, while 1,047 or 80 percent were hardwood. Results from this study showed that 82 percent of the total softwood volume measured was utilized for a product, and 18 percent was left as logging residue. Seventy-two...

  20. North Carolina harvest and utilization study, 2007

    Treesearch

    James W. Bentley; Tony G. Johnson

    2010-01-01

    In 2007, a harvest and utilization study was conducted on 83 operations throughout North Carolina. There were 2,119 total trees measured: 1,323 or 62 percent were softwood, while 796 or 38 percent were hardwood. Results from this study showed that 85 percent of the total softwood volume measured was utilized for a product, and 15 percent was left as logging residue....

  1. Alabama harvest and utilization study, 2008

    Treesearch

    James W. Bentley; Tony G. Johnson

    2008-01-01

    In 2008, a harvest and utilization study was conducted on 80 operations throughout Alabama. There were 2,100 total trees measured; 1,433 or 68 percent were softwood, while 667 or 32 percent were hardwood. Results from this study showed that 88 percent of the total softwood volume measured was utilized for a product, and 12 percent was left as logging residue. Seventy-...

  2. Georgia harvest and utilization study, 2004

    Treesearch

    James W. Bentley; Richard a. Harper

    2006-01-01

    In 2004, a harvest and utilization study was conducted on 96 operations throughout Georgia. There were 2,368 total trees measured, 1,581 or 67 percent were softwood, while 787 or 33 percent were hardwood. Results from this study showed that 86 percent of the total softwood volume measured was utilized for a product, while the other 14 percent was left as logging...

  3. Eastern Texas harvest and utilization study, 2003

    Treesearch

    James W. Bentley; Tony G. Johnson

    2004-01-01

    In 2003, a harvest and utilization study was conducted on 81 operations throughout eastern Texas. There were 2,072 total trees measured, 1,557 or 75 percent were softwood, while 515 or 25 percent were hardwood. Results from this study showed that 87 percent of the total softwood volume measured was utilized for a product, while the other 13 percent was left as logging...

  4. Parallel optical interconnects utilizing VLSI/FLC spatial light modulators

    NASA Astrophysics Data System (ADS)

    Genco, Sheryl M.

    1991-12-01

    Interconnection architectures are a cornerstone of parallel computing systems. However, interconnections can be a bottleneck in conventional computer architectures because of queuing structures that are necessary to handle the traffic through a switch at very high data rates and bandwidths. These issues must find new solutions to advance the state of the art in computing beyond the fundamental limit of silicon logic technology. Today's optoelectronic (OE) technology in particular VLSI/FLC spatial light modulators (SLMs) can provide a unique and innovative solution to these issues. This paper reports on the motivations for the system, describes the major areas of architectural requirements, discusses interconnection topologies and processor element alternatives, and documents an optical arbitration (i.e., control) scheme using `smart' SLMs and optical logic gates. The network topology is given in section 2.1 `Architectural Requirements -- Networks,' but it should be noted that the emphasis is on the optical control scheme (section 2.4) and the system.

  5. [Utilization of optical devices and equipments by students with visual impairment].

    PubMed

    Montilha, Rita de Cássia Ietto; Temporini, Edméa Rita; Nobre, Maria Inês Rubo de Souza; Gasparetto, Maria Elisabete Rodrigues Freire; Kara-José, Newton

    2006-01-01

    To verify perceptions and conduct of students with visual impairment regarding devices and equipment utilized in schooling process. A transversal descriptive study on a population of 12-year-old or older students in schooling process, affected by congenital or acquired visual impairment, inserted in the government teaching system of Campinas during the year 2000. An interview quiz, created based on an exploratory study was applied. A group of 26 students, 46% of them with low vision and 53.8% affected by blindness was obtained. Most of the students were from fundamental teaching courses (65.4%), studying in schools with classrooms provided with devices (73.1%). Among the resources used in reading and writing activities, 94.1% of the students reported they used the Braille system and 81.8% reported that the reading subject was dictated by a colleague. Most of the students with low vision wore glasses (91.7%), and 33.3% utilized a magnifying glass as optical devices. Among the non-optical devices, the most common were the environmental ones, getting closer to the blackboard (75.0%) and to the window (66.7%) for better lighting. It became evident that students with low vision eye-sight made use of devices meant for bearers of blindness, such as applying the Braille system. A reduced number of low vision students making use of optical and non-optical devices applicable to their problems were observed, indicating a probable unawareness of their visual potential and the appropriate devices to improve efficiency.

  6. Utility transforms of optical fields employing deformable mirror.

    PubMed

    Wang, Feiling

    2011-11-15

    Diffraction optical devices of modest degrees of freedom (DOF), such as deformable mirrors, have not been exploited as general-purpose transformers of optical fields. Described in this Letter is a method that guides deformable mirrors to optimal surfaces allowed by the DOF for various desirable outcomes. The method is based on a modal optimization procedure with the help of Walsh functions in controlling the variables of the mirrors, i.e. the actuators. It is shown that a deformable mirror of modest DOF can provide field transformations for arbitrary beam-splitting, formation of ring-shaped beams, and coherent beam combining.

  7. Utilizing Optical Coherence Tomography in the Nondestructive and Noncontact Measurement of Egg Shell Thickness

    PubMed Central

    2014-01-01

    The goal of this study was to measure the thickness of egg shells without any contact and by utilizing a nondestructive method that sends infrared light beam on the egg. We obtain measurement resolutions on the order of 7 μm up to a penetration depth of 1.7 mm from the actual surface of the egg shell. The measurement results we obtained show that optical coherence tomography can be used to accurately determine the egg shell thickness. Scanning the light beam over the surface allows for measuring the egg profile and monitoring the variations of shell thickness. Since this information gives a quantitative value for the uniformity of the egg shell structure, we anticipate that optical coherence tomography may be used in the quantitative evaluation of egg quality in in-line automated inspection systems. PMID:25133208

  8. Utilizing optical coherence tomography in the nondestructive and noncontact measurement of egg shell thickness.

    PubMed

    Sabuncu, Metin; Akdoğan, Mete

    2014-01-01

    The goal of this study was to measure the thickness of egg shells without any contact and by utilizing a nondestructive method that sends infrared light beam on the egg. We obtain measurement resolutions on the order of 7 μm up to a penetration depth of 1.7 mm from the actual surface of the egg shell. The measurement results we obtained show that optical coherence tomography can be used to accurately determine the egg shell thickness. Scanning the light beam over the surface allows for measuring the egg profile and monitoring the variations of shell thickness. Since this information gives a quantitative value for the uniformity of the egg shell structure, we anticipate that optical coherence tomography may be used in the quantitative evaluation of egg quality in in-line automated inspection systems.

  9. West Virginia harvest and utilization study, 2008

    Treesearch

    Jan Wiedenbeck; Shawn. Grushecky

    2014-01-01

    Thirty active harvesting operations were part of a harvest and utilization study conducted in West Virginia in 2008. Data were collected on roundwood product and residue yields obtained from trees of different sizes, species, and qualities. This study was modeled after studies conducted on a regular and frequent basis by the Forest Inventory and Analysis unit in the...

  10. Understanding local forces in electrophoretic ink systems: utilizing optical tweezers to explore electrophoretic display devices

    NASA Astrophysics Data System (ADS)

    Wei, David L.; Dickinson, Mark R.; Smith, N.; Gleeson, Helen F.

    2016-09-01

    Optical tweezers can be used as a valuable tool to characterize electrophoretic display (EPD) systems. EPDs are ubiquitous with e-readers and are becoming a commonplace technology where reflective, low-power displays are required; yet the physics of some features crucial to their operation remains poorly defined. We utilize optical tweezers as a tool to understand the motion of charged ink particles within the devices and show that the response of optically trapped electrophoretic particles can be used to characterize electric fields within these devices. This technique for mapping the force can be compared to simulations of the electric field in our devices, thus demonstrating that the electric field itself is the sole governor of the particle motion in an individual-particle regime. By studying the individual-particle response to the electric field, we can then begin to characterize particle motion in `real' systems with many particles. Combining optical tweezing with particle tracking techniques, we can investigate deviations in many particle systems from the single-particle case.

  11. Surface Plasmon Resonance-Based Fiber Optic Sensors Utilizing Molecular Imprinting

    PubMed Central

    Gupta, Banshi D.; Shrivastav, Anand M.; Usha, Sruthi P.

    2016-01-01

    Molecular imprinting is earning worldwide attention from researchers in the field of sensing and diagnostic applications, due to its properties of inevitable specific affinity for the template molecule. The fabrication of complementary template imprints allows this technique to achieve high selectivity for the analyte to be sensed. Sensors incorporating this technique along with surface plasmon or localized surface plasmon resonance (SPR/LSPR) provide highly sensitive real time detection with quick response times. Unfolding these techniques with optical fiber provide the additional advantages of miniaturized probes with ease of handling, online monitoring and remote sensing. In this review a summary of optical fiber sensors using the combined approaches of molecularly imprinted polymer (MIP) and the SPR/LSPR technique is discussed. An overview of the fundamentals of SPR/LSPR implementation on optical fiber is provided. The review also covers the molecular imprinting technology (MIT) with its elementary study, synthesis procedures and its applications for chemical and biological anlayte detection with different sensing methods. In conclusion, we explore the advantages, challenges and the future perspectives of developing highly sensitive and selective methods for the detection of analytes utilizing MIT with the SPR/LSPR phenomenon on optical fiber platforms. PMID:27589746

  12. Surface Plasmon Resonance-Based Fiber Optic Sensors Utilizing Molecular Imprinting.

    PubMed

    Gupta, Banshi D; Shrivastav, Anand M; Usha, Sruthi P

    2016-08-29

    Molecular imprinting is earning worldwide attention from researchers in the field of sensing and diagnostic applications, due to its properties of inevitable specific affinity for the template molecule. The fabrication of complementary template imprints allows this technique to achieve high selectivity for the analyte to be sensed. Sensors incorporating this technique along with surface plasmon or localized surface plasmon resonance (SPR/LSPR) provide highly sensitive real time detection with quick response times. Unfolding these techniques with optical fiber provide the additional advantages of miniaturized probes with ease of handling, online monitoring and remote sensing. In this review a summary of optical fiber sensors using the combined approaches of molecularly imprinted polymer (MIP) and the SPR/LSPR technique is discussed. An overview of the fundamentals of SPR/LSPR implementation on optical fiber is provided. The review also covers the molecular imprinting technology (MIT) with its elementary study, synthesis procedures and its applications for chemical and biological anlayte detection with different sensing methods. In conclusion, we explore the advantages, challenges and the future perspectives of developing highly sensitive and selective methods for the detection of analytes utilizing MIT with the SPR/LSPR phenomenon on optical fiber platforms.

  13. ELECTRO-OPTIC PROJECTION STUDY.

    DTIC Science & Technology

    light modulation. The light valve tubes used in the study employ an electron beam to develop discrete electric fields through an electro - optic material...Characteristics of two electro - optic materials, potassium dihydrogen phosphate and potassium dideuterium phosphate, were measured in order to optimize the

  14. Secure optical communication system utilizing deformable MEMS mirrors

    NASA Astrophysics Data System (ADS)

    Ziph-Schatzberg, Leah; Bifano, Thomas; Cornelissen, Steven; Stewart, Jason; Bleier, Zvi

    2009-02-01

    An optical communication system suitable for voice, data retrieval from remote sensors and identification is described. The system design allows operation at ranges of several hundred meters. The heart of the system is a modulated MEMS mirror that is electrostatically actuated and changes between a flat reflective state and a corrugated diffractive state. A process for mass producing these mirrors at low cost was developed and is described. The mirror was incorporated as a facet in a hollow retro-reflector, allowing temporal modulation of an interrogating beam and the return of the modulated beam to the interrogator. This system thus consists of a low power, small and light communication node with large (about 60°) angular extent. The system's range and pointing are determined by the interrogator /detector/demodulator (Transceiver) unit. The transceiver is comprised of an optical channel to establish line of sight communication, an interrogating laser at 1550nm, an avalanche photo diode to detect the return signal and electronics to drive the laser and demodulate the detected signal and convert it to an audio signal. A functional prototype system was built using a modified compact optical sight as the transceiver. Voice communication in free space was demonstrated. The design and test of major components and the complete system are discussed.

  15. Optical Disc Utilized As A Data Storage System For Reconnaissance

    NASA Astrophysics Data System (ADS)

    Herzog, Donald G.

    1984-01-01

    Electra-optic and Radar sensing reconnaissance systems have many advantages including remote transmission and image data processing that conventional film camera systems do not have. However, data storage and retrieval that was naturally and easily accomplished with film must now be accommodated by other techniques. The optical disc data storage and retrieval systems offer significant advantage towards fulfilling this need. This paper will provide an overview description of the technology, some of the fundamental alternatives of configuration approach, and some examples of where it may be considered in the reconnaissance system. Silver halide film has been and still is the work horse of the image based reconnaissance field. It will not be replaced in the near future either, but rather a gradual transition to total electronic systems is expected. It is not the intent of this paper to debase film, because in fact it has its advantages. We have learned to optimize its advantages and minimize its disadvantages. However optical disc systems have a definite role to play in the reconnaissance field.

  16. Florida harvest and utilization study, 2008

    Treesearch

    James W. Bentley; Tony G. Johnson

    2009-01-01

    In 2008, a harvest and utilization study was conducted on 82 operationsthroughout Florida. There were 2,114 total trees measured: 1,670 or79 percent were softwood, while 444 or 21 percent were hardwood. Resultsfrom this study showed that 85 percent of the total softwood volumemeasured was...

  17. Virginia harvest and utilization study, 2007

    Treesearch

    James W. Bentley; Tony G. Johnson

    2009-01-01

    In 2007, a harvest and utilization study was conducted on 81 operationsthroughout Virginia. There were 2,016 total trees measured; 1,086 or54 percent were softwood, while 930 or 46 percent were hardwood. Resultsfrom this study showed that 86 percent of the total softwood volumemeasured was...

  18. Liquefaction chemistry and kinetics: Hydrogen utilization studies

    SciTech Connect

    Rothenberger, K.S.; Warzinski, R.P.; Cugini, A.V.

    1995-12-31

    The objectives of this project are to investigate the chemistry and kinetics that occur in the initial stages of coal liquefaction and to determine the effects of hydrogen pressure, catalyst activity, and solvent type on the quantity and quality of the products produced. The project comprises three tasks: (1) preconversion chemistry and kinetics, (2) hydrogen utilization studies, and (3) assessment of kinetic models for liquefaction. The hydrogen utilization studies work will be the main topic of this report. However, the other tasks are briefly described.

  19. Optical study of pulsars

    NASA Astrophysics Data System (ADS)

    Sanwal, Divas

    The Crab Pulsar emits radiation at all wavelengths from radio to extreme γ-rays including the optical. We have performed extremely high time resolution multicolor photometry of the Crab Pulsar at optical wavelengths to constrain the high energy emission models for pulsars. Our observations with 1 microsecond time resolution are a factor of 20 better than the previous best observations. We have completely resolved the peak of the main pulse of the Crab Pulsar in optical passbands. The peaks of the main pulse and the interpulse move smoothly from the rising branch to the falling branch with neither a flat top nor a cusp. We find that the peak of the Crab Pulsar main pulse in the B band arrives 140 microseconds before the peak of the radio pulse. The color of the emission changes across the phase. The maximum variation in the color ratio is about 25%. The bluest color occurs in the bridge region between the main pulse and the interpulse. The Crab Pulsar has faded by 2 +/- 2.8% since the previous observations in 1991 using the same instrument. The statistics of photon arrival times are consistent with atmospheric scintillation causing most of the variations in addition to the mean pulse variations in the shape. However, the autocorrelation function (ACF) of the Crab Pulsar light curve shows extra correlations at very short time scales. We identify two time scales, one at about 20 microseconds and another one at about 1000 microseconds at which we observe a break in the ACF. We conclude that these short timescale correlations are internal to the pulsar. We attribute the extra correlation observed in our data to microstructures. This is the first time evidence for microstructures has been observed outside the radio wavelengths. The upturn in the ACF at short time scales depends on the color. The U band shows about 10% more correlation at short time scales while the R band shows only about 3% change. We have also observed the young X-ray pulsar PSR 0656+14 at optical

  20. Cooperative educational project for optical technicians utilizing amateur telescope making

    NASA Astrophysics Data System (ADS)

    Williamson, Ray

    2004-01-01

    In the modern optical shop, technicians are typically skilled machine operators who work on only one phase of the manufacture for each and every component. The product is designed, specified, methodized, scheduled and integrated by people off the shop floor. Even at the component level, the people inside the shop usually see only one stage of completion. In an effort to make the relevance of their work visible; to demonstrate competence to their peers; to gain appreciation for the work of others; and to give them a meaningful connection with the functions of optical systems, I created "The Telescope Project" for my former employer. I invited those interested to participate in an after-hours, partially subsidized project to build telescopes for themselves. The ground-rules included that we would all make the same design (thus practicing consensus and configuration management); that we would all work on every phase (thus learning from each other); and that we would obtain our parts by random lot at the end (thus making quality assurance a personal issue). In the process the participating technicians learned about optical theory, design, tolerancing, negotiation, scheduling, purchasing, fabrication, coating and assembly. They developed an appreciation for each other's contributions and a broader perspective on the consequences of their actions. In the end, each obtained a high-quality telescope for his or her personal use. Several developed an abiding love for astronomy. The project generated much interest from technicians who didn"t initially choose to participate. In this paper I describe the project in detail.

  1. Atmospheric studies by optical methods

    NASA Astrophysics Data System (ADS)

    Steen, Åke

    The 19th Annual European Meeting on Atmospheric Studies by Optical Methods was held in Kiruna, Sweden, from August 10 to 14. About 120 scientists from thirteen countries contributed talks and posters to eight topical sessions.The annual optical meeting, which was first held in Stockholm in 1972, provides a platform for the exchange of ideas, scientific results, and instrumental information on atmospheric studies collected by optical methods. Although the primary objective is to stimulate high-level scientific discussions, social activities are included in the conference program to expose participants to the host city's local culture, industry, and sights. Participants from all parts of the world are welcome to attend.

  2. Optimization of spectral band utilization in gridless WDM optical network

    NASA Astrophysics Data System (ADS)

    Martins, Indayara B.; Aldaya, Ivan; Perez-Sanchez, G.; Gallion, Philippe

    2014-02-01

    In this paper, the effects of gridless spectrum allocation in Wavelength Division Multiplexed (WDM) optical networks are examined. The advanced modulation formats and multi-rate transmissions of the signals, which are key parameters in the optical system project, are taken into account. The consumed spectrum, as well as the impact of linear and nonlinear impairments on the signal transmission, are compared to WDM network adopting standard grid and gridless ITU. To analyze the influence of these physical effects, some key network design parameters are monitored and evaluated, such as the guard band size, the signal occupied bandwidth, the laser power and the quality of channels. The applied signal modulation formats were On/Off Keying (OOK), Quadrature Phase Shift keying (QPSK), and Dual Polarization State Phase Modulation (DP-QPSK), whereas the transmission rate per wavelength was varied from 10 Gb/s to 100Ghz. The guard band, signal band, and laser power were swept and the resulted Bit Error Rate (BER) was estimated from the eye-diagram. Analytical calculations and simulations are conducted in order to evaluate the impact of the gridless spectrum allocation on both the spectral consumption and the signal quality of transmission (QoT). Results reveal that a gridless transmission system reduces the spectral consumption while offering an acceptable QoT. This work was carried out with both analytical modeling and numerical calculation using the Optisystem as well as Matlab.

  3. Stadium Site Utilization Study. University of Cincinnati.

    ERIC Educational Resources Information Center

    Caudill, Rowlett, and Scott, New York, NY.

    An evaluative study of the University of Cincinnati stadium site shows its potential with relation to the existing campus. Conclusions and recommendations concerning its future utilization are presented, based upon consideration of the following--(1) basic university planning policies, (2) assets and liabilities of the site, (3) the decision to…

  4. Waveguide Studies for Fiber Optics and Optical Signal Processing Applications.

    DTIC Science & Technology

    1980-04-01

    beam expander is shown in Fig. 2 -i. The beam, which is expanded to approximately 100 Wm, can be deflected acousto - optically to make a spectrum analyzer...3 2 . DBR Lasers for Fiber Optics and Optical Signal Processing Sources ......... ................. 4 4. Studies of LiNbO 3...6 Chapter 1. Wave Beam Expansion ....... ............. 9 Chapter 2 . DBR Lasers for Fiber Optics and Optical Signal Processing Sources

  5. A novel nanoarchitecture with optical, solar, medical and biochemical utility

    NASA Astrophysics Data System (ADS)

    Naughton, M. J.; Kempa, K.; Ren, Z. F.

    2009-03-01

    We discuss a nanoscale platform offering widespread utility in nanophotonics, photovoltaics, visual prosthetics, and biological and chemical sensing. As a subwavelength wave-guide architecture, these nanostructures can be used in array form for high efficiency solar cells, as well as in a wide range of nanoscale manipulations of light without deleterious plasmonic effects. They are also being developed as a high electrode-density (10^8/cm^2) retinal implant. Finally, a modification of the basic structure enables the fabrication of a highly sensitive ``nanocavity'' biochemical sensor. We will report on aspects of each application. We also thank the following collaborators: N. Argenti, D. Cai, T.C. Chiles, P. Dhakal, Y. Gao, T. Kirkpatrick, Y.C. Lan, G. McMahon, J.I. Oh, B. Rizal, J. Rybczynski.

  6. Polymer Optical Fiber Sensor and the Prediction of Sensor Response Utilizing Artificial Neural Networks

    NASA Astrophysics Data System (ADS)

    Haroglu, Derya

    characteristics: reproducibility, accuracy, selectivity, aging, and resolution. Artificial neural network (ANN), a mathematical model formed by mimicking the human nervous system, was used to predict the sensor response. Qwiknet (version 2.23) software was used to develop ANNs and according to the results of Qwiknet the prediction performances for training and testing data sets were 75%, and 83.33% respectively. In this dissertation, Chapter 1 describes the worldwide plastic optical fiber (POF) and fiber optic sensor markets, and the existing textile structures used in fiber optic sensing design particularly for the applications of biomedical and structural health monitoring (SHM). Chapter 2 provides a literature review in detail on polymer optical fibers, fiber optic sensors, and occupancy sensing in the passenger seats of automobiles. Chapter 3 includes the research objectives. Chapter 4 presents the response of POF to tensile loading, bending, and cyclic tensile loading with discussion parts. Chapter 5 includes an e-mail based survey to prioritize customer needs in a Quality Function Deployment (QFD) format utilizing Analytic Hierarchy Process (AHP) and survey results. Chapter 6 describes the POF sensor design and the behavior of it under pressure. Chapter 7 provides a data analysis based on the experimental results of Chapter 6. Chapter 8 presents the summary of this study and recommendations for future work.

  7. Studies of Bistable Optical Devices.

    DTIC Science & Technology

    1982-05-15

    a concept to simultaneously process over 2500 parallel bits in a nanosecond, in a linear array. 3. Studies of bistability in new materials and new...Bistable Optical Devices. 25 IV. Bistability in New Materials .... ............ .. 34 A. Saturable Absorber Dyes ... ........... .. 34 A-1. Experimental...large number of resolvable spots. We have investigated.both new materials and new geo- metries for use in bistable optical devices with a view toward

  8. Manufacturing challenges of optical current and voltage sensors for utility applications

    SciTech Connect

    Yakymyshyn, C.P.; Brubaker, M.A.; Johnston, P.M.; Reinbold, C.

    1997-12-01

    Measurement of voltages and currents in power transmission and distribution systems are critical to the electric utility industry for both revenue metering and reliability. Nonconventional instrument transformers based on intensity modulation of optical signals have been reported in the literature for more than 20 years. Recently described devices using passive bulk optical sensor elements include the Electro-Optic Voltage Transducer (EOVT) and Magneto-Optic Current Transducer (MOCT). These technologies offer substantial advantages over conventional instrument transformers in accuracy, optical isolation bandwidth, environmental compatibility, weight and size. This paper describes design and manufacturing issues associated with the EOVT and the Optical Metering Unit (OMU) recently introduced by ABB with field installation results presented for prototype units in the 345 kV and 420 kV voltage classes. The OMU incorporates an EOVT and MOCT to monitor the voltage and current on power transmission lines using a single free-standing device.

  9. Architecture and design of optical path networks utilizing waveband virtual links

    NASA Astrophysics Data System (ADS)

    Ito, Yusaku; Mori, Yojiro; Hasegawa, Hiroshi; Sato, Ken-ichi

    2016-02-01

    We propose a novel optical network architecture that uses waveband virtual links, each of which can carry several optical paths, to directly bridge distant node pairs. Future photonic networks should not only transparently cover extended areas but also expand fiber capacity. However, the traversal of many ROADM nodes impairs the optical signal due to spectrum narrowing. To suppress the degradation, the bandwidth of guard bands needs to be increased, which degrades fiber frequency utilization. Waveband granular switching allows us to apply broader pass-band filtering at ROADMs and to insert sufficient guard bands between wavebands with minimum frequency utilization offset. The scheme resolves the severe spectrum narrowing effect. Moreover, the guard band between optical channels in a waveband can be minimized, which increases the number of paths that can be accommodated per fiber. In the network, wavelength path granular routing is done without utilizing waveband virtual links, and it still suffers from spectrum narrowing. A novel network design algorithm that can bound the spectrum narrowing effect by limiting the number of hops (traversed nodes that need wavelength path level routing) is proposed in this paper. This algorithm dynamically changes the waveband virtual link configuration according to the traffic distribution variation, where optical paths that need many node hops are effectively carried by virtual links. Numerical experiments demonstrate that the number of necessary fibers is reduced by 23% compared with conventional optical path networks.

  10. Performance Analysis of Optical CDMA Systems Utilizing Optical Encoding in Presence of Interference and Receiver Noises

    NASA Astrophysics Data System (ADS)

    Sabbagh, Abbasali Ghorban; Kakhki, Mohammad Molavi

    2011-09-01

    In this paper, performance of incoherent and asynchronous optical CDMA (OCDMA) systems employing “optical encoding” is investigated and the results are compared with the results obtained when the encoding is performed in electrical domain. These investigations are performed for receiver structures that employ a single hard limiter (SHL), a double optical hard limiter (DHL) and also for the structures without a hard limiter (WHL). In addition, “electrical encoding” OCDMA systems using DHL in their receiver structures are investigated. In this work, conventional optical orthogonal codes are used and Gaussian approximation is assumed for the output of APD. Besides interference, other destructive effects such as APD and thermal noises are also taken into account. It is shown that when the number of users N is equal to or greater than pulsed laser's modulation extinction ratio Me , for all receiver structures (SHL, DHL and WHL) “optical encoding” systems are superior to their “electrical encoding” counterparts and this superiority becomes much more apparent in SHL and DHL receivers. We will also show that when N < Me , “optical encoding” WHL systems outperform their “electrical encoding” counterparts. Our results also indicate that the performance of “optical encoding” SHL systems approaches the performance of DHL systems as the transmitted power increases.

  11. Study of optical Laue diffraction

    NASA Astrophysics Data System (ADS)

    Chakravarthy, Giridhar; Allam, Srinivasa Rao; Satyanarayana, S. V. M.; Sharan, Alok

    2014-10-01

    We present the study of the optical diffraction pattern of one and two-dimensional gratings with defects, designed using desktop pc and printed on OHP sheet using laser printer. Gratings so prepared, using novel low cost technique provides good visual aid in teaching. Diffraction pattern of the monochromatic light (632.8nm) from the grating so designed is similar to that of x-ray diffraction pattern of crystal lattice with point defects in one and two-dimensions. Here both optical and x-ray diffractions are Fraunhofer. The information about the crystalline lattice structure and the defect size can be known.

  12. Study of optical Laue diffraction

    SciTech Connect

    Chakravarthy, Giridhar E-mail: aloksharan@email.com; Allam, Srinivasa Rao E-mail: aloksharan@email.com; Satyanarayana, S. V. M. E-mail: aloksharan@email.com; Sharan, Alok E-mail: aloksharan@email.com

    2014-10-15

    We present the study of the optical diffraction pattern of one and two-dimensional gratings with defects, designed using desktop pc and printed on OHP sheet using laser printer. Gratings so prepared, using novel low cost technique provides good visual aid in teaching. Diffraction pattern of the monochromatic light (632.8nm) from the grating so designed is similar to that of x-ray diffraction pattern of crystal lattice with point defects in one and two-dimensions. Here both optical and x-ray diffractions are Fraunhofer. The information about the crystalline lattice structure and the defect size can be known.

  13. A balloon ozone measurement utilizing an optical absorption cell and an ejector air sampler

    NASA Technical Reports Server (NTRS)

    Hilsenrath, E.; Ashenfelter, T. E.

    1976-01-01

    Stratospheric ozone was measured from a balloon utilizing an ultraviolet absorption cell. The ambient air was sampled by means of an aspirator attached to the output end of the optical cell. A nominal ozone distribution was obtained from 16 km to the float altitude of 38 km.

  14. Optical fibre long period grating spectral actuators utilizing ferrofluids as outclading overlayers

    NASA Astrophysics Data System (ADS)

    Konstantaki, M.; Candiani, A.; Pissadakis, S.

    2011-03-01

    Results are presented on the spectral tuning of optical fibre long period gratings utilizing water and oil based ferrofluids as outclading overlayers, under static magnetic field stimulus. Two approaches are adopted for modifying the ambient refractive index at the position of the long period grating. In the first approach, a water based ferrofluid is controllably translated along the length of the grating via a magnetic field. Changes as high as 7.5nm and 6.5dB are monitored in the wavelength and strength, respectively, of the attenuation bands of the grating. The repeatable performance of this device for repetitive forward and backward translation verifies that no ferrofluidic residue is left on the fibre, due to silanization cladding functionalisation. In the second approach, the refractive index of an oil based ferrofluidic overlayer is modified through the magneto-optical effect. For an applied static magnetic field in the order of 400 Gauss the strength of the attenuation band of the grating is modified by more than 10% while its spectral position remains unaffected. Accordingly for the implementation of the last approach, the magnetically induced refractive index changes of ferrofluids of different solution concentrations are studied by employing diffraction efficiency measurements.

  15. Microcapillary electrophoresis chips utilizing controllable micro-lens structures and buried optical fibers for on-line optical detection.

    PubMed

    Hsiung, Suz-Kai; Lee, Chun-Hong; Lee, Gwo-Bin

    2008-05-01

    In this study, a new design of a controllable micro-lens structure capable of the enhancement of LIF detection system has been demonstrated, which can be further integrated with buried optical fibers on a micro-CE chip for sample separation and detection. Two pneumatic side-chambers were placed between a micro-CE channel and an optical fiber channel. The intervals between the side-chamber and the microchannel were used to form two surfaces of the controllable micro-lens structure. Deformations of the two surfaces can be generated after pressurized index-matching fluid was injected into the pneumatic side-chambers. The side-chambers can be deflected as a double convex lens to focus both the excitation light source and the fluorescent emission signal. The profile and the focal length of the micro-lens structure can be actively adjusted by applying different liquid pressures so that biosamples with a low concentration can be detected. Using low-cost polymeric materials such as polydimethylsiloxane, rapid and reliable fabrication techniques involving standard lithography and replication process was employed for the formation of the proposed chip device. Experimental results revealed the controllable micro-lens structure can be successfully deformed as a convex lens to focus the laser light source and the collected fluorescence signal can be enhanced accordingly. The power amplitude of excitation laser light can be enhanced by 5.4-fold. FITC dye and DNA markers were then utilized for micro-CE testing. The results indicated that the signal amplitude could be enhanced 2.5-fold when compared to the case without the activation of the micro-lens. According to the experimental results, the developed device has a great potential to be integrated with other microfluidic devices for further biomedical applications.

  16. Matrix operations utilizing multichannel two-dimensional acousto-optic deflector

    NASA Astrophysics Data System (ADS)

    Barocsi, Attila; Jakab, Laszlo; Richter, Peter I.

    1994-01-01

    A linear scanning light deflector, or Bragg-cell, is a widely utilized acousto-optic (AO) signal processing device. Its application is, however, limited due to its line scanning property. To overcome this deficiency an area (or matrix) scanning deflector can be built by consecutively placing two, orthogonally positioned, linear deflectors. A more sophisticated method, however, is the realization of a `monolithic' area scanning device, or 2-D (XY-) deflector, that contains a single Bragg cell. If each dimension of the cell has several input channels the element can serve as a special optical processor in various applications. In this work a multichannel XY-deflector is examined with special regard to its utilization as a fast optical crossbar switch and matrix processor. An experimental set-up with a 2 * 2 channel cell is also demonstrated.

  17. Case studies in electric utility competition litigation

    SciTech Connect

    Orr, J.A.; Hawks, B.K.

    1994-12-31

    Although electric utilities in the US in many ways operate as highly regulated monopolies, federal and state regulation has not eliminated competition in the electric utility industry. This article describes trends in utility competition litigation as they have evolved in Georgia and other parts of the country.

  18. Multiple Optical Traps with a Single-Beam Optical Tweezer Utilizing Surface Micromachined Planar Curved Grating

    NASA Astrophysics Data System (ADS)

    Kuo, Ju-Nan; Chen, Kuan-Yu

    2010-11-01

    In this paper, we present a single-beam optical tweezer integrated with a planar curved diffraction grating for microbead manipulation. Various curvatures of the surface micromachined planar curved grating are systematically investigated. The planar curved grating was fabricated using multiuser micro-electro-mechanical-system (MEMS) processes (MUMPs). The angular separation and the number of diffracted orders were determined. Experimental results indicate that the diffraction patterns and curvature of the planar curved grating are closely related. As the curvature of the planar curved grating increases, the vertical diffraction angle increases, resulting in the strip patterns of the planar curved grating. A single-beam optical tweezer integrated with a planar curved diffraction grating was developed. We demonstrate a technique for creating multiple optical traps from a single laser beam using the developed planar curved grating. The strip patterns of the planar curved grating that resulted from diffraction were used to trap one row of polystyrene beads.

  19. Nonlinear optical studies of surfaces

    SciTech Connect

    Shen, Y.R.

    1994-07-01

    The possibly of using nonlinear optical processes for surface studies has attracted increasing attention in recent years. Optical second harmonic generation (SHG) and sum frequency generation (SFG), in particular, have been well accepted as viable surface probes. They have many advantages over the conventional techniques. By nature, they are highly surface-specific and has a submonolayer sensitivity. As coherent optical processes, they are capable of in-situ probing of surfaces in hostile environment as well as applicable to all interfaces accessible by light. With ultrafast pump laser pulses, they can be employed to study surface dynamic processes with a subpicosecond time resolution. These advantages have opened the door to many exciting research opportunities in surface science and technology. This paper gives a brief overview of this fast-growing new area of research. Optical SHG from a surface was first studied theoretically and experimentally in the sixties. Even the submonolayer surface sensitivity of the process was noticed fairly early. The success was, however, limited because of difficulties in controlling the experimental conditions. It was not until the early 1980`s that the potential of the process for surface analysis was duly recognized. The first surface study by SHG was actually motivated by the then active search for an understanding of the intriguing surface enhanced Raman scattering (SERS). It had been suspected that the enhancement in SERS mainly came from the local-field enhancement due to local plasmon resonances and pointing rod effect on rough metal surfaces. In our view, Raman scattering is a two-photon process and is therefore a nonlinear optical effect.

  20. Performance improvement of optical RZ-receiver by utilizing an all-optical waveform converter

    NASA Astrophysics Data System (ADS)

    Matsuura, Motoharu; Kishi, Naoto; Miki, Tetsuya

    2005-06-01

    A practical receiver scheme with all-optical waveform conversion is proposed and demonstrated. To mitigate influence of the timing jitter of the received signal, the proposed receiver employs a semiconductor optical amplifier (SOA)-based waveform converter, which can generate signal pulses with a rectangular-like profile. We have evaluated the receiver performances of the conventional and proposed schemes. The receiver sensitivity improvement of 0.7 dB and the phase-margin enlargement of 60 % were simultaneously achieved in comparison with the conventional receiver scheme.

  1. Optical Studies of Active Comets

    NASA Technical Reports Server (NTRS)

    Jewitt, David

    1998-01-01

    This grant was to support optical studies of comets close enough to the sun to be outgassing. The main focus of the observations was drawn to the two extraordinarily bright comets Hyakutake and Hale-Bopp, but other active comets were also studied in detail during the period of funding. Major findings (all fully published) under this grant include: (1) Combined optical and submillimeter observations of the comet/Centaur P/Schwassmann-Wachmann 1 were used to study the nature of mass loss from this object. The submillimeter observations show directly that the optically prominent dust coma is ejected by the sublimation of carbon monoxide. Simultaneous optical-submillimeter observations allowed us to test earlier determinations of the dust mass loss rate. (2) We modelled the rotation of cometary nuclei using time-resolved images of dust jets as the primary constraint. (3) We obtained broad-band optical images of several comets for which we subsequently attempted submillimeter observations, in order to test and update the cometary ephemerides. (4) Broad-band continuum images of a set of weakly active comets and, apparently, inactive asteroids were obtained in BVRI using the University of Hawaii 2.2-m telescope. These images were taken in support of a program to test the paradigm that many near-Earth asteroids might be dead or dormant comets. We measured coma vs. nucleus colors in active comets (finding that coma particle scattering is different from, and cannot be simply related to, nucleus color). We obtained spectroscopic observations of weakly active comets and other small bodies using the HIRES spectrograph on the Keck 10-m telescope. These observation place sensitive limits to outgassing from these bodies, aided by the high (40,000) spectral resolution of HIRES.

  2. Power coupling in multicore optical fiber tapers utilizing out-cladding ferrofluids

    NASA Astrophysics Data System (ADS)

    Tagoudi, Eirini; Milenko, Karolina; Pissadakis, Stavros

    2016-04-01

    Herein we present the experimental implementation of a power coupling device that combines the technology of tapered, multicore microstructured optical fibres (MOFs) with ferrofluidic overlayers. Power coupling between different cores of a tapered, multicore MOF is demonstrated, utilizing magneto-refraction effects induced by magnetic field stimulus into a ferrofluidic outcladding surrounding of the multicore optical fibre taper. By tapering the multicore all-solid MOF to a specific diameter, the excitation of all the adjacent cores through the central one is achieved. Transmission spectra measurements of the individual cores proved that light coupling between fiber cores can be manipulated by magnetic field stimulus. We anticipate that such a type of magneto-tunable power-coupling photonic device can find applications in optical magnetometry, imaging and optical communications.

  3. Microwave vs optical crosslink study

    NASA Technical Reports Server (NTRS)

    Kwong, Paulman W.; Bruno, Ronald C.; Marshalek, Robert G.

    1992-01-01

    The intersatellite links (ISL's) at geostationary orbit is currently a missing link in commercial satellite services. Prior studies have found that potential application of ISL's to domestic, regional, and global satellites will provide more cost-effective services than the non-ISL's systems (i.e., multiple-hop systems). In addition, ISL's can improve and expand the existing satellite services in several aspects. For example, ISL's can conserve the scarce spectrum allocated for fixed satellite services (FSS) by avoiding multiple hopping of the relay stations. ISL's can also conserve prime orbit slot by effectively expanding the geostationary arc. As a result of the coverage extension by using ISL's more users will have direct access to the satellite network, thus providing reduced signal propagation delay and improved signal quality. Given the potential benefits of ISL's system, it is of interest to determine the appropriate implementations for some potential ISL architectures. Summary of the selected ISL network architecture as supplied by NASA are listed. The projected high data rate requirements (greater than 400 Mbps) suggest that high frequency RF or optical implementations are natural approaches. Both RF and optical systems have their own merits and weaknesses which make the choice between them dependent on the specific application. Due to its relatively mature technology base, the implementation risk associated with RF (at least 32 GHz) is lower than that of the optical ISL's. However, the relatively large antenna size required by RF ISL's payload may cause real-estate problems on the host spacecraft. In addition, because of the frequency sharing (for duplex multiple channels communications) within the limited bandwidth allocated, RF ISL's are more susceptible to inter-system and inter-channel interferences. On the other hand, optical ISL's can offer interference-free transmission and compact sized payload. However, the extremely narrow beam widths (on the

  4. Fiber optic gyroscope for automobiles utilizing integrated optical gyrochip and elliptical core polarization-maintaining optical fiber

    NASA Astrophysics Data System (ADS)

    Yuhara, Toshiya; Kumagai, Tatsuya; Iizuka, Hisao; Kajioka, Hiroshi; Mekada, Naoyuki

    1994-03-01

    We have investigated fiber optic gyroscopes that use phase-modulation signal processing for use in automobiles. These gyroscopes use an integrated optical gyrochip and low-cost elliptical-core polarization-maintaining optical fiber. Fiber-to-fiber insertion loss deviation is less than +/- 0.4 dB at a wavelength of 0.83 micrometers over a temperature range of -30 to +80 degree(s)C, while the core dimensions of pigtailed fiber are as small as 4 X 1 micrometers 2. A gyroscope was developed for navigation systems and on board testing is now being performed. A gyroscope for chassis control systems is also being developed.

  5. Phase-shifted Bragg microstructured optical fiber gratings utilizing infiltrated ferrofluids.

    PubMed

    Candiani, Alessandro; Margulis, Walter; Sterner, Carola; Konstantaki, Maria; Pissadakis, Stavros

    2011-07-01

    Results are presented on the efficient spectral manipulation of uniform and chirped Bragg reflectors inscribed in microstructured optical fibers utilizing short lengths of ferrofluids infiltrated in their capillaries. The infiltrated ferrofluidic defects can generate either parasitic reflection notch features in uniform Bragg reflectors of up to 80% visibility and ~0.1 nm spectral shift or tunability of the bandwidth and strength reflection up to 100% when introduced into chirped gratings. Spectra are presented for different spatial positions and optical characteristics of the ferrofluidic section.

  6. A Conceptual Framework for Studying Knowledge Utilization.

    ERIC Educational Resources Information Center

    Paul, Douglas

    This paper, written from an organizational perspective, begins with an examination of the deficiencies of knowledge utilization and educational change literature. It suggests the explication of descriptive and heuristic conceptual dimensions as one approach for facilitating a descriptive perspective of knowldge utilization. The efficacy of three…

  7. Photovoltaic utility/customer interface study

    NASA Astrophysics Data System (ADS)

    Eichler, C. H.; Hayes, T. P.; Matthews, M. M.; Wilraker, V. F.

    1980-12-01

    The technical, economic, and legal and regulatory issues of interconnecting small, privately-owned, on-site photovoltaic generating systems to an electric utility are addressed. Baseline residential, commercial and industrial class photovoltaic systems were developed. Technical issues of concern affecting this interconnection were identified and included fault protection, undervoltage protection, lamp flicker, revenue metering, loss of synchromism, electrical safety, prevention of backfeeding a de-energized utility feeder, effects of on-site generation on utility relaying schemes, effects of power conditioner harmonic distortion on the electric utility, system isolation, electromagnetic interference and site power factor as seen by the utility. Typical interconnection wiring diagrams were developed for interconnecting each class of baseline photovoltaic generating system.

  8. Utilization of purified cellulose in fiber studies.

    PubMed

    Penner, M H; Liaw, E T

    1990-01-01

    Purified cellulose-type fiber products are widely used in experimental nutrition. Their use in a broad spectrum of studies may potentially lead to the acceptance of the misconception that the various commercially available cellulose products are equivalent. In this paper we have attempted to show that this is not the case. The comparative structural data of Table 2 and the compositional data of Olsen et al provide examples which indicate that purified cellulose preparations should not necessarily be considered equivalent. Unfortunately, our current lack of understanding of how fibers are metabolized and how they may affect specific physiological parameters makes it difficult to determine which, if any, of the measurable structural and chemical properties will be of relevance for a given in vivo study. At present, it appears that researchers utilizing/evaluating the consequences of consuming a purified cellulose-type fiber would be prudent to provide at least a limited amount of data on the properties of the cellulose preparation used in their studies. The characterization of the cellulose product may be done by a variety of methods depending on the expertise of the laboratory. The methods and results discussed in this paper provide an example of the type of information which may be obtained from an in vitro characterization of cellulose products.

  9. Fast Switches for Optical Communication Utilizing Optical Kerr or Ellipse Rotation Effect.

    DTIC Science & Technology

    1981-03-01

    LaMacchia, "Optically Induced Refractive Index Changes in BaTiO , .I. Appl. Phys. 41, 5188 (170). SIONTII’ \\’ 1I ’: NliOBATV’ SUN) AND BARIUM SODIUM NIOBAT ...D.L. Staebler, and A.W. Stephens, "Holographic Storage in Doped Barium Sodium Niobate (BaNaNh () )," Appl. Phys. Lett. 18, 307 1971). .. V. ui K.D...POTASSIUM TAINTALATE NIOBATE (KTN) 1. F.S. Chen, "A Laser-Induced lnhomogeneity of Refractive Indices in KTN," J. Appl. Phys. 38, 3418 (1967). 2. D. von

  10. Fringe visibility degeneration utilizing a rotating optical flat for holographic multiplexing purposes.

    PubMed

    Matrisch, Jan; Seela, Johannes; Altmeyer, Stefan

    2016-10-01

    A device concept utilizing a rotating optical flat to degenerate the fringe visibility for simultaneously holographic multiplexing purposes is presented. The device basically consists of a rotating slanted optical flat. The rotation induces a periodically varying phase shift to a transmitting wave, which causes a specific degeneration of the maximum achievable time-average visibility. This property can be used to expose independent gratings simultaneously into one photopolymer film with a single coherent light source. Theoretical investigations of the resulting time-average visibility are carried out and presented in detail. Experimental results are compared to the theoretical findings and discussed. The presented device is capable of decreasing the visibility to the desired degree. Thus, it is well suited for holographic multiplexing purposes. A conceptual setup utilizing the device for holographic angular multiplexing is suggested.

  11. Demonstration of the stabilization technique for nonplanar optical resonant cavities utilizing polarization

    SciTech Connect

    Akagi, T.; Araki, S.; Funahashi, Y.; Honda, Y.; Okugi, T.; Omori, T.; Shimizu, H.; Terunuma, N.; Urakawa, J.; Miyoshi, S.; Takahashi, T. Tanaka, R.; Uesugi, Y.; Yoshitama, H.; Sakaue, K.; Washio, M.

    2015-04-15

    Based on our previously developed scheme to stabilize nonplanar optical resonant cavities utilizing polarization caused by a geometric phase in electromagnetic waves traveling along a twisted path, we report an application of the technique for a cavity installed in the Accelerator Test Facility, a 1.3-GeV electron beam accelerator at KEK, in which photons are generated by laser-Compton scattering. We successfully achieved a power enhancement of 1200 with 1.4% fluctuation, which means that the optical path length of the cavity has been controlled with a precision of 14 pm under an accelerator environment. In addition, polarization switching utilizing a geometric phase of the nonplanar cavity was demonstrated.

  12. A Circumzenithal Arc to Study Optics Concepts with Geometrical Optics

    ERIC Educational Resources Information Center

    Isik, Hakan

    2017-01-01

    This paper describes the formation of a circumzenithal arc for the purpose of teaching light and optics. A circumzenithal arc, an optic formation rarely witnessed by people, is formed in this study using a water-filled cylindrical glass illuminated by sunlight. Sunlight refracted at the top and side surfaces of the glass of water is dispersed into…

  13. Precision short-pulse damage test station utilizing optical parametric chirped-pulse amplification

    SciTech Connect

    Jovanovic, I; Brown, C; Wattellier, B; Nielsen, N; Molander, W; Stuart, B; Pennington, D; Barty, C J

    2004-03-22

    The next generation of high-energy petawatt (HEPW)-class lasers will utilize multilayer dielectric diffraction gratings for pulse compression, due to their high efficiency and high damage threshold for picosecond pulses. The peak power of HEPW lasers will be determined by the aperture and damage threshold of the final dielectric grating in the pulse compressor and final focusing optics. We have developed a short-pulse damage test station for accurate determination of the damage threshold of the optics used on future HEPW lasers. Our damage test station is based on a highly stable, high-beam-quality optical parametric chirped-pulse amplifier (OPCPA) operating at 1053 nm at a repetition rate of 10 Hz. We present the design of our OPCPA system pumped by a commercial Q-switched pump laser and the results of the full system characterization. Initial short-pulse damage experiments in the far field using our system have been performed.

  14. Iron utilization studies in Citrobacter species.

    PubMed

    Khashe, S; Janda, J M

    1996-04-01

    Seventy-one strains of Citrobacter were screened for iron scavenging mechanisms by biologic and chemical assays. Essentially all citrobacteria (70/71) were found to elaborate enterobactin-like siderophores by both biologic and chemical assays, however only c. koseri (C. diversus) was found to produce aerobactin. The concentration of ethylenediamine di(o-hydroxyphenylacetic acid) (EDDA) required to inhibit the growth of individual Citrobacter strains by depleting free iron ranged from 250 micrograms/ml to 100 micrograms/ml. Iron utilization studies of selected citrobacter isolates indicated that hemin and hematin could reverse the effects of iron limitation on growth under iron-stressed conditions (1000 micrograms/ml of EDDA). Two C. koseri strains grown under iron-restricted conditions showed similar changes in their whole cell protein profiles including induction of high molecular mass proteins (72-83 kDa) which may play a role in iron acquisition under iron-stressed conditions. The collective results support an additional virulence-associated mechanism for C. koseri strains which may help explain the greater pathogenic potential this group has for causing serious extraintestinal disease in humans.

  15. The impact of CmapTools utilization towards students' conceptual change on optics topic

    NASA Astrophysics Data System (ADS)

    Rofiuddin, Muhammad Rifqi; Feranie, Selly

    2017-05-01

    Science teachers need to help students identify their prior ideas and modify them based on scientific knowledge. This process is called as conceptual change. One of essential tools to analyze students' conceptual change is by using concept map. Concept Maps are graphical representations of knowledge that are comprised of concepts and the relationships between them. Constructing concept map is implemented by adapting the role of technology to support learning process, as it is suitable with Educational Ministry Regulation No.68 year 2013. Institute for Human and Machine Cognition (IHMC) has developed CmapTools, a client-server software for easily construct and visualize concept maps. This research aims to investigate secondary students' conceptual change after experiencing five-stage conceptual teaching model by utilizing CmapTools in learning Optics. Weak experimental method through one group pretest-posttest design is implemented in this study to collect preliminary and post concept map as qualitative data. Sample was taken purposively of 8th grade students (n= 22) at one of private schools Bandung, West Java. Conceptual change based on comparison of preliminary and post concept map construction is assessed based on rubric of concept map scoring and structure. Results shows significance conceptual change differences at 50.92 % that is elaborated into concept map element such as prepositions and hierarchical level in high category, cross links in medium category and specific examples in low category. All of the results are supported with the students' positive response towards CmapTools utilization that indicates improvement of motivation, interest, and behavior aspect towards Physics lesson.

  16. Utility of AIRS Retrievals for Climate Studies

    NASA Technical Reports Server (NTRS)

    Molnar, Guyla I.; Susskind, Joel

    2007-01-01

    Satellites provide an ideal platform to study the Earth-atmosphere system on practically all spatial and temporal scales. Thus, one may expect that their rapidly growing datasets could provide crucial insights not only for short-term weather processes/predictions but into ongoing and future climate change processes as well. Though Earth-observing satellites have been around for decades, extracting climatically reliable information from their widely varying datasets faces rather formidable challenges. AIRS/AMSU is a state of the art infrared/microwave sounding system that was launched on the EOS Aqua platform on May 4, 2002, and has been providing operational quality measurements since September 2002. In addition to temperature and atmospheric constituent profiles, outgoing longwave radiation and basic cloud parameters are also derived from the AIRS/AMSU observations. However, so far the AIRS products have not been rigorously evaluated and/or validated on a large scale. Here we present preliminary assessments of monthly and 8-day mean AIRS "Version 4.0" retrieved products (available to the public through the DAAC at NASA/GSFC) to assess their utility for climate studies. First we present "consistency checks" by evaluating the time series of means, and "anomalies" (relative to the first 4 full years' worth of AIRS "climate statistics") of several climatically important retrieved parameters. Finally, we also present preliminary results regarding interrelationships of some of these geophysical variables, to assess to what extent they are consistent with the known physics of climate variability/change. In particular, we find at least one observed relationship which contradicts current general circulation climate (GCM) model results: the global water vapor climate feedback which is expected to be strongly positive is deduced to be slightly negative (shades of the "Lindzen effect"?). Though the current AIRS climatology covers only -4.5 years, it will hopefully extend much

  17. A study of optical design and optimization of laser optics

    NASA Astrophysics Data System (ADS)

    Tsai, C.-M.; Fang, Yi-Chin

    2013-09-01

    This paper propose a study of optical design of laser beam shaping optics with aspheric surface and application of genetic algorithm (GA) to find the optimal results. Nd: YAG 355 waveband laser flat-top optical system, this study employed the Light tools LDS (least damped square) and the GA of artificial intelligence optimization method to determine the optimal aspheric coefficient and obtain the optimal solution. This study applied the aspheric lens with GA for the flattening of laser beams using collimated laser beam light, aspheric lenses in order to achieve best results.

  18. Picosecond Optical Studies of Solids.

    NASA Astrophysics Data System (ADS)

    Broomfield, Seth Emlyn

    Available from UMI in association with The British Library. Requires signed TDF. Hot carrier relaxation is studied in the alloy semiconductor Ga_{rm 1-x} Al_{rm x}As by analysis of time-resolved luminescence at 4K. Photoexcited carrier densities in the range 10^{16 } to 10^{18}cm ^{-3} were created by 5ps laser pulses in alloys with x values ranging from 0 to 0.36. Carrier temperature cooling curves are discussed in terms of emission and absorption of non-equilibrium phonons by carriers, intervalley scattering of electrons and alloy disorder effects. Energy relaxation within a band of localised exciton states is studied in Ga_{rm 1 -x}Al_{rm x} As by analysis of time-resolved photoluminescence at 4K with a photoexcited carrier density of 10 ^{14}cm^{-3 }. It is found that the width of the band of localised states increases with the degree of alloy disorder as x ranges from 0 to 0.36. A form for the density of localised states is obtained. The intersite exciton overlap is estimated. Photoluminescence of the semiconductor gallium selenide is measured for carrier densities below 3 times 10^{18}cm ^{-3} at 2K. Biexcitons are identified by analysis of the photoluminescence at high densities. This is confirmed by induced optical absorption experiments. It is shown that biexciton dissociation by interaction with low-energy optical phonons occurs as the lattice temperature is increased. The group velocity of excitonic polaritons is obtained from measurements of the time-of-flight of 5ps optical pulses across a 1mum thick layer of gallium arsenide at 4K. The group velocity has a minimum value of 4 times 10 ^5ms^{-1} at the transverse exciton energy, and has a dependence on photon energy which agrees well with a model describing spatial dispersion of polaritons.

  19. High Performance Optical Coatings Utilizing Tailored Refractive Index Nanoporous Thin Films

    NASA Astrophysics Data System (ADS)

    Poxson, David J.

    Refractive index is perhaps the most important quantity in optics. It is particularly relevant in the field of optical coatings, where the refractive index appears in virtually every optics equation as a figure of merit. Recently it has been demonstrated through control of the deposition angle during oblique-angle electron-beam deposition, nanoporous films of virtually any desired porosity may be accurately deposited. As the porosity of a nanoporous film directly relates to its effective refractive index, the refractive index value of a film may be tailored to any value between that of the bulk material and close to that of air. These two characteristics, namely; (i) tailored-refractive index and (ii) very low-refractive index values close to that of air, offer significant advantages in the design and optical performance in all optical coating applications. In this dissertation we explore optical coating applications whose performance can be greatly enhanced by utilization of a tailored- and low-refractive index nanoporous material system. One such important application is in the design and fabrication of broadband, omnidirectional antireflection (AR) coatings on solar cell devices. To harness the full spectrum of solar energy, Fresnel reflections at the surface of a photovoltaic cell must be reduced as much as possible over the relevant solar wavelength range and over a wide range of incident angles. However, the development of AR coatings embodying omni-directionality over a wide range of wavelengths is challenging. By utilizing the tailored- and low-refractive index properties of the nanoporous material system, in conjunction with a computational genetic algorithm and a predictive quantitative model for the porosity of such nanoporous films, truly optimized AR coatings can be designed and fabricated on solar cells. Here we show that these optimized AR structures demonstrate significant improvement to overall device efficiency. Traditionally, nanoporous films

  20. Surface plasmon resonance based fiber optic detection of chlorine utilizing polyvinylpyrolidone supported zinc oxide thin films.

    PubMed

    Tabassum, Rana; Gupta, Banshi D

    2015-03-21

    A highly sensitive chlorine sensor for an aqueous medium is fabricated using an optical fiber surface plasmon resonance (OFSPR) system. An OFSPR-based chlorine sensor is designed with a multilayer-type platform by zinc oxide (ZnO) and polyvinylpyrollidone (PVP) film morphology manipulations. Among all the methodologies of transduction reported in the field of solid state chemical and biochemical sensing, our attention is focused on the Kretschmann configuration optical fiber sensing technique using the mechanism of surface plasmon resonance. The optical fiber surface plasmon resonance (SPR) chlorine sensor is developed using a multimode optical fiber with the PVP-supported ZnO film deposited over a silver-coated unclad core of the fiber. A spectral interrogation mode of operation is used to characterize the sensor. In an Ag/ZnO/PVP multilayer system, the absorption of chlorine in the vicinity of the sensing region is performed by the PVP layer and the zinc oxide layer enhances the shift in resonance wavelength. It is, experimentally, demonstrated that the SPR wavelength shifts nonlinearly towards the red side of the visible region with an increase in the chlorine concentration in an aqueous medium while the sensitivity of the sensor decreases linearly with an increase in the chlorine concentration. As the proposed sensor utilizes an optical fiber, it possesses the additional advantages of fiber such as less signal degradation, less susceptibility to electromagnetic interference, possibility of remote sensing, probe miniaturization, probe re-usability, online monitoring, small size, light weight and low cost.

  1. Optical fiber temperature sensor utilizing alloyed Zn(x)Cd(1-x)S quantum dots.

    PubMed

    Zhao, Fei; Kim, Jongsung

    2014-08-01

    In this paper, optical fiber temperature sensors have been prepared by using alloyed Zn(x)Cd(1-x)S quantum dots as sensing media. The surface of the optical fiber was silanized to enhance covalent bond between quantum dots and optical fiber. The quantum dots were bonded to the surface of optical fiber and further encapsulated via sol-gel coating using 3-glycidoxypropyl trimethoxysilane (GPTMS) and 3-aminopropyl trimethoxysilane (APTMS) in ethyl alcohol in acidic condition. Quantum dots with green, yellow, and red fluorescence were used. The dependence of photoluminescence (PL) intensity from quantum dots on ambient temperature has been studied. Linear relation between the fluorescent intensity and temperature was obtained from alloyed quantum dots immobilized on the surface of optical fiber. The PL intensity, sensitivity, and thermal stability were increased by the silica encapsulation.

  2. Kauai Island Utility Cooperative energy storage study.

    SciTech Connect

    Akhil, Abbas Ali; Yamane, Mike; Murray, Aaron T.

    2009-06-01

    Sandia National Laboratories performed an assessment of the benefits of energy storage for the Kauai Island Utility Cooperative. This report documents the methodology and results of this study from a generation and production-side benefits perspective only. The KIUC energy storage study focused on the economic impact of using energy storage to shave the system peak, which reduces generator run time and consequently reduces fuel and operation and maintenance (O&M) costs. It was determined that a 16-MWh energy storage system would suit KIUC's needs, taking into account the size of the 13 individual generation units in the KIUC system and a system peak of 78 MW. The analysis shows that an energy storage system substantially reduces the run time of Units D1, D2, D3, and D5 - the four smallest and oldest diesel generators at the Port Allen generating plant. The availability of stored energy also evens the diurnal variability of the remaining generation units during the off- and on-peak periods. However, the net economic benefit is insufficient to justify a load-leveling type of energy storage system at this time. While the presence of storage helps reduce the run time of the smaller and older units, the economic dispatch changes and the largest most efficient unit in the KIUC system, the 27.5-MW steam-injected combustion turbine at Kapaia, is run for extra hours to provide the recharge energy for the storage system. The economic benefits of the storage is significantly reduced because the charging energy for the storage is derived from the same fuel source as the peak generation source it displaces. This situation would be substantially different if there were a renewable energy source available to charge the storage. Especially, if there is a wind generation resource introduced in the KIUC system, there may be a potential of capturing the load-leveling benefits as well as using the storage to dampen the dynamic instability that the wind generation could introduce into

  3. Optically-powered Voltage-supply-device for Effective Utilization of Optical Energy in the Fiber-To-The-Home Network

    NASA Astrophysics Data System (ADS)

    Fukano, Hideki; Shinagawa, Takeshi; Tsuruta, Kenji

    An optically powered device with using InGaAs-Photodiode has been developed. This study aims to harvest light energy (2.8∼500μW) from the FTTH (Fiber To The Home) network and to utilize it for operating remote sensors without external energy sources. First, we designed and evaluated the characteristics of the booster circuit and confirmed that it could boost an input voltage of 0.3 V to 3.0 V. Next, we also evaluated the characteristics of InGaAs photodiode and confirmed that it can output a voltage over 0.3 V at 10-μW input light. We demonstrate that a ready-made sensor can be operated with an input optical power as low as 10 μW.

  4. An improved scheduled traffic model utilizing bandwidth splitting in elastic optical networks

    NASA Astrophysics Data System (ADS)

    Vyas, Upama; Prakash, Shashi

    2016-07-01

    The surge of traffic in today's networks gave birth to elastic optical networking paradigm. In this paper, first we propose to use the scheduled traffic model (STM) in elastic optical networks (EONs) to ensure guaranteed availability of resources to demands which enter into the network with a predetermined start and end times. In optical networks, such demands are referred to as scheduled lightpath demands (SLDs). To increase the amount of bandwidth accepted in network, next we introduce a time aware routing and spectrum assignment (TA-RSA) approach. We observed that provisioning of bulky SLDs has become more challenging in EONs due to enforcement of RSA constraints. To address this challenge, we improve the proposed STM and designed three heuristics for its implementation in EONs. In this work, we collectively refer to these heuristics as bandwidth segmented RSA (BSRSA). The improved STM (iSTM) allows splitting of SLDs in bandwidth dimension by utilizing the knowledge of attributes viz. demand holding time, overlapping in time and bandwidth requested by SLDs. Our numerical results show that BSRSA consistently outperformed over TA-RSA under all distinctive experimental cases that we considered and achieved fairness in serving heterogeneous bandwidth SLDs. The impact of splitting on the number and capacity of transponders at nodes is also gauged. It is observed that ingenious splitting of demands increases the number of resources (on links and nodes) used, and their utilization, leading to an increase in bandwidth accepted in the network.

  5. The DoD Laboratory Utilization Study

    DTIC Science & Technology

    1975-04-28

    ODDR&E view of the Navy laboratories was that: (1) they are well integrated into many of the Navy programs , including fleet support, (2) they possess...an innovative, well structured Tech- nology Base program ; (2) they utilize military personnel in the labora- tories effectively; (3) they specialize...education, an early 4•-,- tour in a Laboratory as a "bench-level" engineer or scientist and usually includes duty in program management as well as

  6. Reconfigurable intensity modulation and direct detection optical transceivers for variable-rate wavelength-division-multiplexing passive optical networks utilizing digital signal processing-based symbol mapper

    NASA Astrophysics Data System (ADS)

    Zhang, Zhiguo; Zhang, Bingbing; Chen, Yanxu; Chen, Xue

    2017-01-01

    Variable-rate intensity modulation and direct detection-based optical transceivers with software-controllable reconfigurability and transmission performance adaptability are experimentally demonstrated, utilizing M-QAM symbol mapping implemented in MATLAB® programs. A frequency division multiplexing-based symbol demapping and wavelength management method is proposed for the symbol demapper and tunable laser management used in colorless optical network unit.

  7. Study of the optical piston

    NASA Astrophysics Data System (ADS)

    Werij, H. G. C.; Haverkort, J. E. M.; Woerdman, J. P.

    1986-05-01

    An experimental and theoretical study of the optical piston, a consequence of the phenomenon of light-induced drift (LID), observed in binary mixtures of Na vapor and a buffer gas, is reported. Good agreement has been found between experiment and existing theory as far as the shape of the Na density profile in the piston is concerned. The piston velocity is anomalously low; this is accounted for by incorporating the effects of adsorption and desorption into the theory. Furthermore, a rate-equation model for LID is introduced which incorporates the fine and hyperfine structure of the level scheme of the Na absorbers; this gives insight into the sublevel velocity distributions and the nonequilibrium part of the total velocity distribution during LID.

  8. Simultaneous chromatic dispersion monitoring and optical modulation format identification utilizing four wave mixing

    NASA Astrophysics Data System (ADS)

    Cui, Sheng; Qiu, Chen; Ke, Changjian; He, Sheng; Liu, Deming

    2015-11-01

    This paper presents a method which is able to monitor the chromatic dispersion (CD) and identify the modulation format (MF) of optical signals simultaneously. This method utilizes the features of the output curve of the highly sensitive all-optical CD monitor based on four wave mixing (FWM). From the symmetric center of the curve CD can be estimated blindly and independently, while from the profile and convergence region of the curve ten commonly used modulation formats can be recognized with simple algorithm based on maximum correlation classifier. This technique does not need any high speed optoelectronics and has no limitation on signal rate. Furthermore it can tolerate large CD distortions and is robust to polarization mode dispersion (PMD) and amplified spontaneous emission (ASE) noise.

  9. Alternative approach for cavitation damage study utilizing repetitive laser pulses

    SciTech Connect

    Ren, Fei; Wang, Jy-An John; Wang, Hong

    2010-01-01

    Cavitation is a common phenomenon in fluid systems that can lead to dramatic degradation of solid materials surface in contact with the cavitating media. Study of cavitation damage has great significance in many engineering fields. Current techniques for cavitation damage study either require large scale equipments or tend to introduce damages from other mechanisms. In this project, we utilized the cavitation phenomenon induced by laser optical breakdown and developed a prototype apparatus for cavitation damage study. In our approach, cavitation was generated by the repetitive pressure waves induced by high-power laser pulses. As proof of principal study, stainless steel and aluminum samples were tested using the novel apparatus. Surface characterization via scanning electron microscopy revealed damages such as indentation and surface pitting, which were similar to those reported in literature using other state-of-the-art techniques. These preliminary results demonstrated the new device was capable of generating cavitation damages and could be used as an alternative method for cavitation damage study.

  10. Optical Frequency Optimization of a High Intensity Laser Power Beaming System Utilizing VMJ Photovoltaic Cells

    NASA Technical Reports Server (NTRS)

    Raible, Daniel E.; Dinca, Dragos; Nayfeh, Taysir H.

    2012-01-01

    An effective form of wireless power transmission (WPT) has been developed to enable extended mission durations, increased coverage and added capabilities for both space and terrestrial applications that may benefit from optically delivered electrical energy. The high intensity laser power beaming (HILPB) system enables long range optical 'refueling" of electric platforms such as micro unmanned aerial vehicles (MUAV), airships, robotic exploration missions and spacecraft platforms. To further advance the HILPB technology, the focus of this investigation is to determine the optimal laser wavelength to be used with the HILPB receiver, which utilizes vertical multi-junction (VMJ) photovoltaic cells. Frequency optimization of the laser system is necessary in order to maximize the conversion efficiency at continuous high intensities, and thus increase the delivered power density of the HILPB system. Initial spectral characterizations of the device performed at the NASA Glenn Research Center (GRC) indicate the approximate range of peak optical-to-electrical conversion efficiencies, but these data sets represent transient conditions under lower levels of illumination. Extending these results to high levels of steady state illumination, with attention given to the compatibility of available commercial off-the-shelf semiconductor laser sources and atmospheric transmission constraints is the primary focus of this paper. Experimental hardware results utilizing high power continuous wave (CW) semiconductor lasers at four different operational frequencies near the indicated band gap of the photovoltaic VMJ cells are presented and discussed. In addition, the highest receiver power density achieved to date is demonstrated using a single photovoltaic VMJ cell, which provided an exceptionally high electrical output of 13.6 W/sq cm at an optical-to-electrical conversion efficiency of 24 percent. These results are very promising and scalable, as a potential 1.0 sq m HILPB receiver of

  11. Free Space Optical Communication Utilizing Mid-Infrared Interband Cascade Laser

    NASA Technical Reports Server (NTRS)

    Soibel, A.; Wright, M.; Farr, W.; Keo, S.; Hill, C.; Yang, R. Q.; Liu, H. C.

    2010-01-01

    A Free Space Optical (FSO) link utilizing mid-IR Interband Cascade lasers has been demonstrated in the 3-5 micron atmospheric transmission window with data rates up to 70 Mb/s and bit-error-rate (BER) less than 10 (exp -8). The performance of the mid-IR FSO link has been compared with the performance of a near-IR link under various fog conditions using an indoor communication testbed. These experiments demonstrated the lower attenuation and scintillation advantages of a mid-IR FSO link through fog than a 1550 nm FSO link.

  12. A novel optical lithography implement utilizing third harmonic generation via metallic tip enhanced near field

    NASA Astrophysics Data System (ADS)

    Zhang, Hui; Zhu, Ning; Mei, Ting; He, Miao; Li, Hao; Chen, Zhenshi

    2017-01-01

    A novel scheme for near-field optical lithography utilizing a metallic tip illuminated by femtosecond laser pulses with proper polarization has been presented. The strongly enhanced near field at the metallic tip offers a localized excitation source for the third harmonic generation in the nonlinear material. The generated third harmonic via excitation of nonlinear photoresist provides good exposure contrast due to the cubic intensity dependence. The spatial resolution of this novel lithography scheme is shown to be better than that of the conventional lithography technique.

  13. Design of a miniature SWIR hyperspectral snapshot imager utilizing multivariate optical elements

    NASA Astrophysics Data System (ADS)

    Priore, Ryan; Dougherty, John; Cohen, Omer; Bikov, Leonid; Hirsh, Itay

    2016-10-01

    CIRTEMO, SCD and Pixelteq have co-developed a miniature short-wave infrared (SWIR) hyperspectral snapshot imager utilizing Multivariate Optical Elements (MOEs). The resultant product may address many of the detection challenges facing multiple markets including commercial, medical, security and defense. This paper highlights the design process of developing MOEs for a targeted application, as well as the technological challenges faced and solutions developed for successful integration of a micro-patterned mosaic array to an InGaAs focal plane array.

  14. Analysis of an all optical de-multiplexer architecture utilizing bevel design for spatially multiplexed optical fiber communication systems

    NASA Astrophysics Data System (ADS)

    Murshid, Syed H.; Finch, Michael F.; Lovell, Gregory L.

    2014-09-01

    Spatial domain multiplexing (SDM) is a system that allows multiple channels of light to traverse a single fiber, utilizing separate spatial regions inside the carrier fiber, thereby applying a new degree of photon freedom for optical fiber communications. These channels follow a helical pattern, the screen projection of which is viewable as concentric rings at the output end of the system. The MIMO nature of the SDM system implies that a typical pin-diode or APD will be unable to distinguish between these channels, as the diode will interpret the combination of the SDM signals from all channels as a single signal. As such, spatial de-multiplexing methods must be introduced to properly detect the SDM based MIMO signals. One such method utilizes a fiber consisting of multiple, concentric, hollow core fibers to route each channel independently and thereby de-mux the signals into separate fibers or detectors. These de-mux fibers consist of hollow core cylindrical structures with beveled edges on one side that gradually taper to route the circular, ring type, output energy patterns into a spot with the highest possible efficiency. This paper analyzes the beveled edge by varying its length and analyzing the total output power for each predetermined length allowing us to simulate ideal bevel length to minimize both system losses as well as total de-mux footprint. OptiBPM simulation engine is employed for these analyses.

  15. Erosive Burning Study Utilizing Ultrasonic Measurement Techniques

    NASA Technical Reports Server (NTRS)

    Furfaro, James A.

    2003-01-01

    A 6-segment subscale motor was developed to generate a range of internal environments from which multiple propellants could be characterized for erosive burning. The motor test bed was designed to provide a high Mach number, high mass flux environment. Propellant regression rates were monitored for each segment utilizing ultrasonic measurement techniques. These data were obtained for three propellants RSRM, ETM- 03, and Castor@ IVA, which span two propellant types, PBAN (polybutadiene acrylonitrile) and HTPB (hydroxyl terminated polybutadiene). The characterization of these propellants indicates a remarkably similar erosive burning response to the induced flow environment. Propellant burnrates for each type had a conventional response with respect to pressure up to a bulk flow velocity threshold. Each propellant, however, had a unique threshold at which it would experience an increase in observed propellant burn rate. Above the observed threshold each propellant again demonstrated a similar enhanced burn rate response corresponding to the local flow environment.

  16. Studies in optical parallel processing. [All optical and electro-optic approaches

    NASA Technical Reports Server (NTRS)

    Lee, S. H.

    1978-01-01

    Threshold and A/D devices for converting a gray scale image into a binary one were investigated for all-optical and opto-electronic approaches to parallel processing. Integrated optical logic circuits (IOC) and optical parallel logic devices (OPA) were studied as an approach to processing optical binary signals. In the IOC logic scheme, a single row of an optical image is coupled into the IOC substrate at a time through an array of optical fibers. Parallel processing is carried out out, on each image element of these rows, in the IOC substrate and the resulting output exits via a second array of optical fibers. The OPAL system for parallel processing which uses a Fabry-Perot interferometer for image thresholding and analog-to-digital conversion, achieves a higher degree of parallel processing than is possible with IOC.

  17. Impact damage detection in filament wound tubes utilizing embedded optical fibers

    NASA Astrophysics Data System (ADS)

    Martin, Anthony R.; Hayes, Simon A.; Fernando, Gerard F.; Hale, Ken F.

    1995-04-01

    Filament wound tubes are currently being used extensively in service because of their superior specific properties and the relatively simple manufacturing technique involved in their properties. However, the reinforcing fibers can suffer from low velocity impact damage (approximately 10 ms-1) during service. Such damage can result in poor post- impact properties which in certain applications can reduce the burst strength below safe working levels. This paper discusses the use of optical fiber sensors, embedded during the filament winding process, to provide information on specified levels of impact damage incurred by the tube during service. The sensors being developed use silica based optical fibers in composites made from E-glass reinforcing fibers and high temperature cure epoxy resins. Various methods of damage detection are being evaluated to select the optimum sensor arrangement. These systems detect changes in the transmission characteristics of the optical fiber. The objective being to produce a working damage detection system which provides sensitive, cheap, accurate and reliable information about the levels of impact damage sustained by the tube. This paper presents initial results from the impact damage detection systems being evaluated for use in filament wound tubes. Issues relating to chemical compatibility between optical fiber sensors and the epoxy resin system were also investigated as part of this study. These results aid selection of the correct optical fiber properties to achieve reliable and sensitive systems. The advantages of using a new profile sensor compared to an optical fiber are also discussed.

  18. Mitigation of time-spatial influence in free-space optical networks utilizing route diversity

    NASA Astrophysics Data System (ADS)

    Libich, J.; Zvanovec, S.; Mudroch, M.

    2012-02-01

    New communication systems are emerging with growing demand on the data traffic. Fiber optics allow us to transfer data of rates higher than hundreds gigabits per second. These systems are usually used for backbone networks, although using of these systems is appearing in last mile connections. Wireless communication systems are still more and more popular owing to fast and cheaper deployment contrary to wire or fiber communication systems. On the other hand, wireless communication systems including free-space optics (FSO) are affected by weather conditions. In order to mitigate these effects, several mitigation techniques were investigated. For instance spatial diversity using more than one transmitter or receiver, auto-tracking of an optical beam, wavelength diversity utilizing radio band links as a backup etc. FSO links may be used in FSO networks to connect several building of a corporation, hospital or university campus. In case of proper network topology, route diversity can contribute to availability enhancement. In this paper, mitigation technique based on the route diversity is presented. Results are compared with hybrid FSO link.

  19. Optical birefringence and molecular orientation of crazed fibres utilizing the phase shifting interferometric technique

    NASA Astrophysics Data System (ADS)

    Sokkar, T. Z. N.; El-Farahaty, K. A.; El-Bakary, M. A.; Omar, E. Z.; Hamza, A. A.

    2017-09-01

    In this article, the features of the phase shifting interferometric technique were utilized to investigate the effect of the presence of crazes in both outer and inner layers on optical birefringence and molecular orientation of polypropylene fibres. The Pluta polarizing interference microscope was used as a phase shifting technique. This method includes adding a stepper motor with a control unit to the micrometer screw of the Pluta microscope. This optical system was calibrated to be used as a phase shifting interferometric technique. The advantage of this technique is that it can detect the crazes in both inner and outer layers of the sample under test. Via this method, the relation between the presence of the crazes (in both inner and outer layers) and the optical molecular orientation of polypropylene (PP) fibres was demonstrated. To clarify the role of this method, the spatial carrier frequency technique was used to show the effect of the presence of the crazes only in the outer layers on the phase distribution values and hence the structural properties of PP fibres.

  20. Optical properties of beam-steering elements utilizing volume holographic gratings

    NASA Astrophysics Data System (ADS)

    Butler, James Jay

    2000-06-01

    An optical beam steering element is a device that is used to control the direction in which a beam of light travels. We have investigated the optical properties of two classes of optical beam steering elements. The first type utilized the polarization dependence of the diffraction efficiency of volume holographic gratings. The second type utilized the fact that the diffraction efficiency of holograms imbibed with a nematic liquid crystal can be controlled by the application of an electric field. In both cases, elements with excellent switching contrasts were fabricated for operation in the visible and near infrared wavelength range including the commonly used telecommunications wavelength of 1.3μm. The holographic recording material that we have used is Polaroid Corporation's DMP-128 photopolymer. This material is porous after exposure and processing, a feature useful in two ways for this work. First, volume gratings with very large refractive index modulations, on the order of 0.2, can be fabricated using this material. Secondly, the pores can be filled with a nematic liquid crystal, resulting in electrically-switchable gratings. In our analysis of polarization-sensitive gratings we have employed several coupled wave theories, each with a different set of approximations. We have found that rigorous coupled wave theory must be used in predicting the diffractive properties of highly modulated volume gratings, where the effects of higher diffraction orders and form birefringence become important. In our analysis of the optical properties of electrically-switchable liquid crystal composite holograms, we have employed a theoretical analysis that treats the birefringent nature of the gratings. The results of Kogelnik theory that neglects the grating anisotropy, a two-wave theory that treats anisotropy, and a formulation of rigorous coupled wave theory that includes anisotropy were compared. We found it was necessary to include the effects of optical anisotropy to

  1. Further Studies on Nonlinear Adaptive Optics,

    DTIC Science & Technology

    1981-04-01

    AD-A9 167 SCIENCE APPLICATIONS INC LA JOLLA CA F/9 20/6 A-A*9 16 FURTHER STUDIES ON NONLINEAR ADAPTIVE OPTICS , 1W _ ASFE APR SI A ELCI. J1 NAGEL. D...FURTHER STUDIES ON NONLINEAR ADAPTIVE OPTICS Apr 8l 7 Submitted to: Director of Physics Air Force Office of Scientific Research ATTN: NP Bldg. 410...1 I STATEMENT OF WORK ...... .. .................... I-I II NONLINEAR ADAPTIVE OPTICS SUMMARY

  2. Market feasibility study of utility battery applications: Penetration of battery energy storage into regulated electric utilities

    SciTech Connect

    Akhil, A.; Kraft, S.; Symons, P.C.

    1997-12-01

    Although recent studies indicate there could be significant opportunities for battery systems in electric utility applications, markets for this and other dispersed energy storage technologies have been slow to develop. Prior analyses had suggested that the slow market development has resulted from reluctance to make the necessary investments on the part of both suppliers and customers. In order to confirm this and other concerns over the utility energy storage market, an assessment has been performed to estimate the potential penetration of batteries into regulated electric utilities. The estimates thus obtained confirm that the possible market for batteries on the utility side of the meter, approximately $280 million annually in 2010, is indeed smaller than indicated by the assessment of potential opportunities had suggested it might be. On the other hand, the estimates for possible market penetration on the customer side of the meter are greater than on the utility-side, particularly in the nearer-term. Of more importance than the numeric results, however, are the comments given by potential customers of utility battery energy storage, and the conclusions regarding ways to increase the attractiveness of utility battery energy storage that result from analyses of these comments.

  3. Specific systems studies of battery energy storage for electric utilities

    SciTech Connect

    Akhil, A.A.; Lachenmeyer, L.; Jabbour, S.J.; Clark, H.K.

    1993-08-01

    Sandia National Laboratories, New Mexico, conducts the Utility Battery Storage Systems Program, which is sponsored by the US Department of Energy`s Office of Energy Management. As a part of this program, four utility-specific systems studies were conducted to identify potential battery energy storage applications within each utility network and estimate the related benefits. This report contains the results of these systems studies.

  4. A study of critical thinking and research utilization among nurses.

    PubMed

    Profetto-McGrath, Joanne; Hesketh, Kathryn L; Lang, Sarah; Estabrooks, Carole A

    2003-04-01

    Previous studies have suggested that critical thinking influences research utilization; however, empirical support for the link between critical thinking dispositions and research utilization is nonexistent. In this article, critical thinking dispositions and research utilization habits are detailed, and the relationship of critical thinking dispositions to research utilization in a sample of 141 nurses working on two acute surgical units and five pediatric units in four tertiary care hospitals are examined. Results indicate a significant positive correlation between the total critical thinking disposition score and overall research utilization. Overall critical thinking disposition correlates significantly with all forms of research utilization, with the exception of symbolic research utilization. These findings indicate a need to foster critical thinking in both nursing education and the work environment.

  5. In-situ health monitoring technique for composite structures utilizing embedded thermal fiber optic sensors

    NASA Astrophysics Data System (ADS)

    Stewart, Anna Kristina

    Health monitoring techniques are necessary for the safety, reliability and longevity of structural components. However, dependable, in-situ, and practical damage detection methods are difficult to develop and implement. In this dissertation, a novel health monitoring technique based on thermography that uses optical fiber thermal sensors to detect damage within a laminated graphite epoxy composite specimen is investigated. The concept follows: when an internal defect exists inside a composite panel and an external heat flux is applied, the defect can hinder the heat from propagating through the panel. Consequently, thermal sensors placed near the defect measure a temperature change when compared to a defect-free panel. Fiber optic sensors are permanently embedded within a structure to allow for direct temperature measurement and an in-situ health monitoring technique. Fiber optic sensors are advantageous primarily due to their multiplexing capabilities. Certain fiber optic technologies permit 1000 point sensors on a single fiber, which in turn reduces the cabling sizes by three orders of magnitude. A comprehensive proof-of-concept study involved five sets of composite samples and a numerical model. The first set validated the concept, the second tested two types of fiber optic sensors, the third provided a thorough study using the superior sensor technology, the fourth provided data to develop a numerical model, and the last set validated the model's findings. The numerical model provided a close approximation to the experimental data, and was used to determine proper sensor placement. The first three sets of specimens used a simulated impact system to induce damage of varying degrees into the samples. The last two sets used artificial damage in the form of Teflon inserts in an effort to quantify the size and location of damage. A flash lamp apparatus rapidly heated the samples while the fiber optic sensors and exterior thermocouples recorded temperature changes

  6. All-optical frequency downconversion technique utilizing a four-wave mixing effect in a single semiconductor optical amplifier for wavelength division multiplexing radio-over-fiber applications.

    PubMed

    Kim, Hyoung-Jun; Song, Jong-In

    2012-03-26

    An all-optical frequency downconversion utilizing a four-wave mixing effect in a single semiconductor optical amplifier (SOA) was experimentally demonstrated for wavelength division multiplexing (WDM) radio-over-fiber (RoF) applications. Two WDM optical radio frequency (RF) signals having 155 Mbps differential phase shift keying (DPSK) data at 28.5 GHz were simultaneously down-converted to two WDM optical intermediate frequency (IF) signals having an IF frequency of 4.5 GHz by mixing with an optical local oscillator (LO) signal having a LO frequency of 24 GHz in the SOA. The bit-error-rate (BER) performance of the RoF up-links with different optical fiber lengths employing all-optical frequency downconversion was investigated. The receiver sensitivity of the RoF up-link with a 6 km single mode fiber and an optical IF signal in an optical double-sideband format was approximately -8.5 dBm and the power penalty for simultaneous frequency downconversion was approximately 0.63 dB. The BER performance showed a strong dependence on the fiber length due to the fiber dispersion. The receiver sensitivity of the RoF up-link with the optical IF signal in the optical single-sideband format was reduced to approximately -17.4 dBm and showed negligible dependence on the fiber length.

  7. A circumzenithal arc to study optics concepts with geometrical optics

    NASA Astrophysics Data System (ADS)

    Isik, Hakan

    2017-05-01

    This paper describes the formation of a circumzenithal arc for the purpose of teaching light and optics. A circumzenithal arc, an optic formation rarely witnessed by people, is formed in this study using a water-filled cylindrical glass illuminated by sunlight. Sunlight refracted at the top and side surfaces of the glass of water is dispersed into its constituent colours. First, multi-colour arcs are observed on paper at the bottom of the glass. Then, a single arc for each colour is observed on the floor when the rays are allowed to propagate to the furthest points from the glass. The change in observations is explained by formulating an equation for the geometry of the situation. The formula relates each point on the first refracting surface for an incoming light ray to a point further from the second refracting surface. Then, a parallel graph is drawn to visualize the superposition of colours to the formation of a single arc. The geometrical optics studies in this paper exemplify the concept of Snell’s law, total internal reflection and dispersion. The duration of the observation on a circumzenithal arc is limited by the altitude of the Sun in the sky. This study depends on the use of astronomy software to track solar altitude. Pedagogical aspects of the study are discussed for inquiry-based teaching and learning of light and optics concepts.

  8. Optical fiber dispersion characterization study

    NASA Technical Reports Server (NTRS)

    Geeslin, A.; Arriad, A.; Riad, S. M.; Padgett, M. E.

    1979-01-01

    The theory, design, and results of optical fiber pulse dispersion measurements are considered. Both the hardware and software required to perform this type of measurement are described. Hardware includes a thermoelectrically cooled injection laser diode source, an 800 GHz gain bandwidth produce avalanche photodiode and an input mode scrambler. Software for a HP 9825 computer includes fast Fourier transform, inverse Fourier transform, and optimal compensation deconvolution. Test set construction details are also included. Test results include data collected on a 1 Km fiber, a 4 Km fiber, a fused spliced, eight 600 meter length fibers concatenated to form 4.8 Km, and up to nine optical connectors.

  9. Paralegal Studies Program. Curriculum Utilization. Final Report.

    ERIC Educational Resources Information Center

    Humphrey, Doris D.

    A program developed a paralegal studies program for Delaware County Community College in the Philadelphia (Pennsylvania) metropolitan area. Activities included gathering of information on paralegal studies as it related to curriculum content; advisory group establishment; curriculum development; training/educational material development; and…

  10. High-pressure optical studies

    SciTech Connect

    Drickamer, H.G.

    1981-01-01

    High pressure experimentation may concern intrinsically high pressure phenomena, or it may be used to gain a better understanding of states or processes at one atmosphere. The latter application is probably more prevelant in condensed matter physics. Under this second rubric one may either use high pressure to perturb various electronic energy levels and from this pressure tuning characterize states or processes, or one can use pressure to change a macroscopic parameter in a controlled way, then measure the effect on some molecular property. In this paper, the pressure tuning aspect is emphasized, with a lesser discussion of macroscopic - molecular relationships. In rare earth chelates the efficiency of 4f-4f emission of the rare earth is controlled by the feeding from the singlet and triplet levels of the organic ligand. These ligand levels can be strongly shifted by pressure. A study of the effect of pressure on the emission efficiency permits one to understand the effect of ligand modification at one atmosphere. Photochromic crystals change color upon irradiation due to occupation of a metastable ground state. In thermochromic crystals, raising the temperature accomplishes the same results. For a group of molecular crystals (anils) at high pressure, the metastable state can be occupied at room temperature. The relative displacement of the energy levels at high pressure also inhibits the optical process. Effects on luminescence intensity are shown to be consistent. In the area of microscopic - molecular relationships, the effect of viscosity and dielectric properties on rates of non-radiative (thermal) and radiative emission, and on peak energy for luminescence is demonstrated. For systems which can emit from either of two excited states depending on the interaction with the environment, the effect of rigidity of the medium on the rate of rearrangement of the excited state is shown.

  11. A rapid excitation-emission matrix fluorometer utilizing supercontinuum white light and acousto-optic tunable filters

    SciTech Connect

    Wang, Wenbo; Wu, Zhenguo; Zhao, Jianhua; Lui, Harvey; Zeng, Haishan

    2016-06-15

    Scanning speed and coupling efficiency of excitation light to optic fibres are two major technical challenges that limit the potential of fluorescence excitation-emission matrix (EEM) spectrometer for on-line applications and in vivo studies. In this paper, a novel EEM system, utilizing a supercontinuum white light source and acousto-optic tunable filters (AOTFs), was introduced and evaluated. The supercontinuum white light, generated by pumping a nonlinear photonic crystal fiber with an 800 nm femtosecond laser, was efficiently coupled into a bifurcated optic fiber bundle. High speed EEM spectral scanning was achieved using AOTFs both for selecting excitation wavelength and scanning emission spectra. Using calibration lamps (neon and mercury argon), wavelength deviations were determined to vary from 0.18 nm to −0.70 nm within the spectral range of 500–850 nm. Spectral bandwidth for filtered excitation light broadened by twofold compared to that measured with monochromatic light between 650 nm and 750 nm. The EEM spectra for methanol solutions of laser dyes were successfully acquired with this rapid fluorometer using an integration time of 5 s.

  12. Retinal damage in chloroquine maculopathy, revealed by high resolution imaging: a case report utilizing adaptive optics scanning laser ophthalmoscopy.

    PubMed

    Bae, Eun Jin; Kim, Kyoung Rae; Tsang, Stephen H; Park, Sung Pyo; Chang, Stanley

    2014-02-01

    A 53-year-old Asian woman was treated with hydroxychloroquine and chloroquine for lupus erythematosus. Within a few years, she noticed circle-shaped shadows in her central vision. Upon examination, the patient's visual acuity was 20 / 25 in both eyes. Humphrey visual field (HVF) testing revealed a central visual defect, and fundoscopy showed a ring-shaped area of parafoveal retinal pigment epithelium depigmentation. Fundus autofluorescence imaging showed a hypofluorescent lesion consistent with bull's eye retinopathy. Adaptive optics scanning laser ophthalmoscope (AO-SLO) revealed patch cone mosaic lesions, in which cones were missing or lost. In addition, the remaining cones consisted of asymmetrical shapes and sizes that varied in brightness. Unlike previous studies employing deformable mirrors for wavefront aberration correction, our AO-SLO approach utilized dual liquid crystal on silicon spatial light modulators. Thus, by using AO-SLO, we were able to create a photographic montage consisting of high quality images. Disrupted cone AO-SLO images were matched with visual field test results and functional deficits were associated with a precise location on the montage, which allowed correlation of histological findings with functional changes determined by HVF. We also investigated whether adaptive optics imaging was more sensitive to anatomical changes compared with spectral-domain optical coherence tomography.

  13. A rapid excitation-emission matrix fluorometer utilizing supercontinuum white light and acousto-optic tunable filters.

    PubMed

    Wang, Wenbo; Wu, Zhenguo; Zhao, Jianhua; Lui, Harvey; Zeng, Haishan

    2016-06-01

    Scanning speed and coupling efficiency of excitation light to optic fibres are two major technical challenges that limit the potential of fluorescence excitation-emission matrix (EEM) spectrometer for on-line applications and in vivo studies. In this paper, a novel EEM system, utilizing a supercontinuum white light source and acousto-optic tunable filters (AOTFs), was introduced and evaluated. The supercontinuum white light, generated by pumping a nonlinear photonic crystal fiber with an 800 nm femtosecond laser, was efficiently coupled into a bifurcated optic fiber bundle. High speed EEM spectral scanning was achieved using AOTFs both for selecting excitation wavelength and scanning emission spectra. Using calibration lamps (neon and mercury argon), wavelength deviations were determined to vary from 0.18 nm to -0.70 nm within the spectral range of 500-850 nm. Spectral bandwidth for filtered excitation light broadened by twofold compared to that measured with monochromatic light between 650 nm and 750 nm. The EEM spectra for methanol solutions of laser dyes were successfully acquired with this rapid fluorometer using an integration time of 5 s.

  14. A fiber optics system for monitoring utilization of ZnO adsorbent beds during desulfurization for logistic fuel cell applications

    NASA Astrophysics Data System (ADS)

    Sujan, Achintya; Yang, Hongyun; Dimick, Paul; Tatarchuk, Bruce J.

    2016-05-01

    An in-situ fiber optic based technique for direct measurement of capacity utilization of ZnO adsorbent beds by monitoring bed color changes during desulfurization for fuel cell systems is presented. Adsorbents composed of bulk metal oxides (ZnO) and supported metal oxides (ZnO/SiO2 and Cusbnd ZnO/SiO2) for H2S removal at 22 °C are examined. Adsorbent bed utilization at breakthrough is determined by the optical sensor as the maximum derivative of area under UV-vis spectrum from 250 to 800 nm observed as a function of service time. Since the response time of the sensor due to bed color change is close to bed breakthrough time, a series of probes along the bed predicts utilization of the portion of bed prior to H2S breakthrough. The efficacy of the optical sensor is evaluated as a function of inlet H2S concentration, H2S flow rate and desulfurization in presence of CO, CO2 and moisture in feed. A 6 mm optical probe is employed to measure utilization of a 3/16 inch ZnO extrudate bed for H2S removal. It is envisioned that with the application of the optical sensor, desulfurization can be carried out at high adsorbent utilization and low operational costs during on-board miniaturized fuel processing for logistic fuel cell power systems.

  15. Passive Fiber Optic Gyro Study.

    DTIC Science & Technology

    1979-10-01

    34. FORWORD The report summarizes the principles of operation of the passive fiber optic gyro. It starts with a discussion of the Sagnac effect and...polarization and the angle of the " fast " axis varied nonlinearly and that the two effects are partially independent. Based on tests with a 200 meter length of

  16. Utilizing laser interference lithography to fabricate hierarchical optical active nanostructures inspired by the blue Morpho butterfly

    NASA Astrophysics Data System (ADS)

    Siddique, Radwanul H.; Faisal, Abrar; Hünig, Ruben; Bartels, Carolin; Wacker, Irene; Lemmer, Uli; Hoelscher, Hendrik

    2014-09-01

    The famous non-iridescent blue of the Morpho butter by is caused by a `Christmas tree' like nanostructure which is a challenge for common fabrication techniques. Here, we introduce a method to fabricate this complex morphology utilizing dual beam interference lithography. We add a reflective coating below the photoresist to create a second interference pattern in vertical direction by exploiting the back reflection from the substrate. This vertical pattern exposes the lamella structure into the photosensitive polymer while the horizontal interference pattern determines the distance of the ridges. The photosensitive polymer is chosen accordingly to create the Christmas tree' like tapered shape. The resulting artificial Morpho replica shows brilliant non-iridescent blue up to an incident angle of 40. Its optical properties are close to the original Morpho structure because the refractive index of the polymer is close to chitin. Moreover, the biomimetic surface is water repellent with a contact angle of 110.

  17. Characterizing the Spatial and Temporal Distribution of Aerosol Optical Thickness Over the Atlantic Basin Utilizing GOES-8 Multispectral Data

    NASA Technical Reports Server (NTRS)

    Fox, Robert; Prins, Elaine Mae; Feltz, Joleen M.

    2001-01-01

    In recent years, modeling and analysis efforts have suggested that the direct and indirect radiative effects of both anthropogenic and natural aerosols play a major role in the radiative balance of the earth and are an important factor in climate change calculations. The direct effects of aerosols on radiation and indirect effects on cloud properties are not well understood at this time. In order to improve the characterization of aerosols within climate models it is important to accurately parameterize aerosol forcing mechanisms at the local, regional, and global scales. This includes gaining information on the spatial and temporal distribution of aerosols, transport regimes and mechanisms, aerosol optical thickness, and size distributions. Although there is an expanding global network of ground measurements of aerosol optical thickness and size distribution at specific locations, satellite data must be utilized to characterize the spatial and temporal extent of aerosols and transport regimes on regional and global scales. This study was part of a collaborative effort to characterize aerosol radiative forcing over the Atlantic basin associated with the following three major aerosol components in this region: urban/sulfate, Saharan dust, and biomass burning. In-situ ground measurements obtained by a network of sun photometers during the Smoke Clouds and Radiation Experiment in Brazil (SCAR-B) and the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) were utilized to develop, calibrate, and validate a Geostationary Operational Environmental Satellite (GOES)-8 aerosol optical thickness (AOT) product. Regional implementation of the GOES-8 AOT product was used to augment point source measurements to gain a better understanding of the spatial and temporal distributions of Atlantic basin aerosols during SCAR-B and TARFOX.

  18. Using geometric algebra to study optical aberrations

    SciTech Connect

    Hanlon, J.; Ziock, H.

    1997-05-01

    This paper uses Geometric Algebra (GA) to study vector aberrations in optical systems with square and round pupils. GA is a new way to produce the classical optical aberration spot diagrams on the Gaussian image plane and surfaces near the Gaussian image plane. Spot diagrams of the third, fifth and seventh order aberrations for square and round pupils are developed to illustrate the theory.

  19. Space Station RT and E Utilization Study

    NASA Technical Reports Server (NTRS)

    Wunsch, P. K.; Anderson, P. H.

    1989-01-01

    Descriptive information on a set of 241 mission concepts was reviewed to establish preliminary Space Station outfitting needs for technology development missions. The missions studied covered the full range of in-space technology development activities envisioned for early Space Station operations and included both pressurized volume and attached payload requirements. Equipment needs were compared with outfitting plans for the life sciences and microgravity user communities, and a number of potential outfitting additions were identified. Outfitting implementation was addressed by selecting a strawman mission complement for each of seven technical themes, by organizing the missions into flight scenarios, and by assessing the associated outfitting buildup for planning impacts.

  20. Optic Aphasia: A Case Study

    PubMed Central

    Lee, Jae-Hong

    2006-01-01

    Optic aphasia is a rare syndrome in which patients are unable to name visually presented objects but have no difficulty in naming those objects on tactile or verbal presentation. We report a 79-year-old man who exhibited anomic aphasia after a left posterior cerebral artery territory infarction. His naming ability was intact on tactile and verbal semantic presentation. The results of the systematic assessment of visual processing of objects and letters indicated that he had optic aphasia with mixed features of visual associative agnosia. Interestingly, although he had difficulty reading Hanja (an ideogram), he could point to Hanja letters on verbal description of their meaning, suggesting that the processes of recognizing objects and Hanja share a common mechanism. PMID:20396529

  1. Outer planets mission television subsystem optics study

    NASA Technical Reports Server (NTRS)

    1972-01-01

    An optics study was performed to establish a candidate optical system design for the proposed NASA Mariner Jupiter/Saturn 77 mission. The study was performed over the 6-month period from January through June 1972. The candidate optical system contains both a wide angle (A) and a narrow angle (B) lens. An additional feature is a transfer mirror mechanism that allows image transfer from the B lens to the vidicon initially used for the A lens. This feature adds an operational redundancy to the optical system in allowing for narrow angle viewing if the narrow angle vidicon were to fail. In this failure mode, photography in the wide angle mode would be discontinued. The structure of the candidate system consists mainly of aluminum with substructures of Invar for athermalization. The total optical system weighs (excluding vidicons) approximately 30 pounds and has overall dimensions of 26.6 by 19.5 by 12.3 inches.

  2. Acousto-Optic Beam Steering Study

    DTIC Science & Technology

    1994-08-01

    8217111 INK $ 1 1 illl iII Ill i, R L-TR-94-121 !1!1Il t 11I1!I!11! ilI, / Final Technical Report August 1994 ACOUSTO - OPTIC BEAM STEERING STUDY Harris...contractual obligations or notices on a specific document require that it be returned. For i ..........I ,, ACOUSTO - OPTIC BEAM STEERING STUDY H. W...4. TITLE AND SUBTITLE 5. FUNDING NUMBERS ACOUSTO - OPTIC BEAM STEERING STUDY C - F30602-91-C-0131 PE - 63215C 6. AUTHOR(S) PR - 1405 TA - 02 H. W

  3. Utilizing a Tower Based System for Optical Sensing of Ecosystem Carbon Fluxes

    NASA Astrophysics Data System (ADS)

    Huemmrich, K. F.; Corp, L. A.; Middleton, E.; Campbell, P. K. E.; Landis, D.; Kustas, W. P.

    2015-12-01

    Optical sampling of spectral reflectance and solar induced fluorescence provide information on the physiological status of vegetation that can be used to infer stress responses and estimates of production. Multiple repeated observations are required to observe the effects of changing environmental conditions on vegetation. This study examines the use of optical signals to determine inputs to a light use efficiency (LUE) model describing productivity of a cornfield where repeated observations of carbon flux, spectral reflectance and fluorescence were collected. Data were collected at the Optimizing Production Inputs for Economic and Environmental Enhancement (OPE3) fields (39.03°N, 76.85°W) at USDA Beltsville Agricultural Research Center. Agricultural Research Service researchers measured CO2 fluxes using eddy covariance methods throughout the growing season. Optical measurements were made from the nearby tower supporting the NASA FUSION sensors. The sensor system consists of two dual channel, upward and downward looking, spectrometers used to simultaneously collect high spectral resolution measurements of reflected and fluoresced light from vegetation canopies at multiple view angles. Estimates of chlorophyll fluorescence, combined with measures of vegetation pigment content and the Photosynthetic Reflectance Index (PRI) derived from the spectral reflectance are compared with CO2 fluxes over diurnal periods for multiple days. The relationships among the different optical measurements indicate that they are providing different types of information on the vegetation and that combinations of these measurements provide improved retrievals of CO2 fluxes than any index alone

  4. Utilization

    NASA Astrophysics Data System (ADS)

    Lu, Guozhi; Zhang, Ting-An; Zhu, Xiaofeng; Liu, Yan; Wang, Yanxiu; Guo, Fangfang; Zhao, Qiuyue; Zheng, Chaozhen

    2014-09-01

    In this study, a calcification-carbonation method is proposed to change the equilibrium structure of red mud produced from the Bayer process. The thermodynamics of both calcification and carbonation processes has been elucidated. In addition, the non-isothermal kinetics involved in the calcification process and the effects of different parameters on the hydrogarnet synthesis and carbonation decomposition are experimentally investigated using pure reagents. The results indicate that through a two-step carbonation treatment of calcified slag by the new method, the mass ratio of alumina to silica ( A/S) of the modified red mud has decreased to 0.44 and the Na2O content drops to 0.12 wt.% at the carbonation temperature of 120°C under the CO2 pressure of 1.2 MPa. The newly modified red mud could be directly used in the cement industry.

  5. Preliminary design of Laser Utilizing Communications Equipment (LUCE) installed on Optical Inter-Orbit Communications Engineering Test Satellite (OICETS)

    NASA Astrophysics Data System (ADS)

    Nakagawa, Keizo; Yamamoto, Akio

    1995-04-01

    The Laser Utilizing Communications Equipment (LUCE) installed on the Optical Inter-orbit Communications Engineering Test Satellite (OICETS) has been developed by NASDA (National Space Development Agency of Japan) in order to perform the inter-satellite optical link experiment with ARTEMIS (Advanced Relay and Technology Mission Satellite) of ESA (European Space Agency). To acquire the acquisition, tracking and pointing technology of an optical link is aimed by this in-orbit experiment. The preliminary design of OICETS including LUCE was finished and its result is reported in this paper.

  6. Lithium-niobate-based integrated optic chip utilizing digital electrode layout for use in a miniature fiber optic rate sensor

    NASA Astrophysics Data System (ADS)

    Ner, Manjeet S.; Groellmann, Peter; Mutter, Gerhard

    1995-09-01

    This paper describes to the best of our knowledge the first implementation of a lithium niobate based 8 bit electroded integrated optic waveguide fiber optic gyro chip referred here as 'Digi- MIOC' (digital-electroded multifunction integrated optic chip, which has been used in a Sagnac effect exploiting microfiber optic rate sensor ((mu) -FORS) developed by LITEF. The paper highlights various features of a Digi-MIOC, such as design philosophy, fabrication aspects, and test procedures to evaluate static and dynamic characteristics of the electro-optic parameters. When used in closed loop operation, the Digi-MIOC forms the key optical component of a (mu) -FORS to aid the required optical-to-electrical signal processing to give linear output for input rates of rotation. Various test results and features of LITEF's (mu) - FORS, such as small size, large rotation rate measurement potential, low drive power, and high reliabliity are also highlighted.

  7. Combining Radar and Optical Data for Forest Disturbance Studies

    NASA Technical Reports Server (NTRS)

    Ranson, K. Jon; Smith, David E. (Technical Monitor)

    2002-01-01

    Disturbance is an important factor in determining the carbon balance and succession of forests. Until the early 1990's researchers have focused on using optical or thermal sensors to detect and map forest disturbances from wild fires, logging or insect outbreaks. As part of a NASA Siberian mapping project, a study evaluated the capability of three different radar sensors (ERS, JERS and Radarsat) and an optical sensor (Landsat 7) to detect fire scars, logging and insect damage in the boreal forest. This paper describes the data sets and techniques used to evaluate the use of remote sensing to detect disturbance in central Siberian forests. Using images from each sensor individually and combined an assessment of the utility of using these sensors was developed. Transformed Divergence analysis and maximum likelihood classification revealed that Landsat data was the single best data type for this purpose. However, the combined use of the three radar and optical sensors did improve the results of discriminating these disturbances.

  8. Transsynaptic retinal degeneration in optic neuropathies: optical coherence tomography study.

    PubMed

    Sriram, Prema; Graham, Stuart L; Wang, Chenyu; Yiannikas, Con; Garrick, Raymond; Klistorner, Alexander

    2012-03-09

    Recently demonstrated neuronal loss in the inner nuclear layer of the retina in multiple sclerosis (MS) and glaucoma raises the question of a primary (possibly immune-mediated) or secondary (transsynaptic) mechanism of retinal damage in these diseases. In the present study we used optical coherence tomography to investigate retrograde retinal transsynaptic degeneration in patients with long-standing and severe loss of ganglion cells due to optic neuropathy. Fifteen eyes of glaucoma patients with visual field defect limited to upper hemifield and 15 eyes of MS patients with previous episode of optic neuritis (ON) and extensive loss of ganglion cells were imaged using spectral-domain optical coherence tomography and compared with two groups of age-matched controls. Combined retinal ganglion cell layer/inner plexiform layer (GCL/IPL) thickness and inner nuclear layer (INL) thickness were analyzed. In the glaucoma group there was a significant (P = 0.0005) reduction of GCL/IPL thickness in the lower (affected) retina compared with normal controls; however INL thickness was not statistically reduced (P = 0.49). In the MS group reduction of GCL/IPL thickness in both hemifields of ON eyes was also significant (P = 0.0001 and P < 0.0001 for inferior and superior retina respectively). However, similar to the glaucomatous eyes, there was no significant reduction of INL thickness in both hemifields (P = 0.25 and P = 0.45). This study demonstrates no significant loss of INL thickness in parts of the retina with long-standing and severe loss of retinal ganglion cells.

  9. The Michigan regulatory incentives study for electric utilities

    SciTech Connect

    Reid, M.W.; Weaver, E.M. )

    1991-06-17

    This is the final report of Phase I of the Michigan Regulatory Incentives Study for Electric Utilities, a three-phase review of Michigan's regulatory system and its effects on resource selection by electric utilities. The goal of Phase I is to identify and analyze financial incentive mechanisms that encourage selection of resources in accord with the principles of integrated resource planning (IRP) or least-cost planning (LCP). Subsequent study phases will involve further analysis of options and possibly a collaborative formal effort to propose regulatory changes. The Phase I analysis proceeded in three steps: (1) identification and review of existing regulatory practices that affect utilities; selection of resources, particularly DSM; (2) preliminary analysis of ten financial mechanisms, and selection of three for further study; (3) detailed analysis of the three mechanisms, including consideration of how they could be implemented in Michigan and financial modeling of their likely impacts on utilities and ratepayers.

  10. Utilization of coincidence criteria in absolute length measurements by optical interferometry in vacuum and air

    NASA Astrophysics Data System (ADS)

    Schödel, R.

    2015-08-01

    Traceability of length measurements to the international system of units (SI) can be realized by using optical interferometry making use of well-known frequencies of monochromatic light sources mentioned in the Mise en Pratique for the realization of the metre. At some national metrology institutes, such as Physikalisch-Technische Bundesanstalt (PTB) in Germany, the absolute length of prismatic bodies (e.g. gauge blocks) is realized by so-called gauge-block interference comparators. At PTB, a number of such imaging phase-stepping interference comparators exist, including specialized vacuum interference comparators, each equipped with three highly stabilized laser light sources. The length of a material measure is expressed as a multiple of each wavelength. The large number of integer interference orders can be extracted by the method of exact fractions in which the coincidence of the lengths resulting from the different wavelengths is utilized as a criterion. The unambiguous extraction of the integer interference orders is an essential prerequisite for correct length measurements. This paper critically discusses coincidence criteria and their validity for three modes of absolute length measurements: 1) measurements under vacuum in which the wavelengths can be identified with the vacuum wavelengths, 2) measurements under air in which the air refractive index is obtained from environmental parameters using an empirical equation, and 3) measurements under air in which the air refractive index is obtained interferometrically by utilizing a vacuum cell placed along the measurement pathway. For case 3), which corresponds to PTB’s Kösters-Comparator for long gauge blocks, the unambiguous determination of integer interference orders related to the air refractive index could be improved by about a factor of ten when an ‘overall dispersion value,’ suggested in this paper, is used as coincidence criterion.

  11. Optical 3D Deformation Measurement Utilizing Non-planar Surface for the Development of an “Intelligent Tire”

    NASA Astrophysics Data System (ADS)

    Matsuzaki, Ryosuke; Hiraoka, Naoki; Todoroki, Akira; Mizutani, Yoshihiro

    Intelligent tires, also known as smart tires, are equipped with sensors to monitor the strain of the interior surface and the rolling radius of tire, and are expected to improve the reliability of tires and tire control systems such as anti-lock braking systems (ABS). However, the high stiffness of an attached sensor like a strain gauge causes sensors to debond from the tire rubber. In the present study, a novel optical method is used for the concurrent monitoring of in-plane strain and out-of-plane displacement (rolling radius) utilizing the non-planar surface of the monitoring object. The optical method enables noncontact measurement of strain distribution. The in-plane strain and out-of-plane displacement are calculated by using image processing with an image of the interior surface of a tire that is taken with a single CCD camera fixed on the wheel rim. This new monitoring system is applied to an aluminum beam and a commercially available radial tire. As a result, the monitoring system provides concurrent measurement of in-plane strain, out-of-plane displacement and tire pressure, and is shown to be an effective monitoring system for intelligent tires.

  12. Utilizing the ratio and the summation of two spectral lines for estimation of optical depth: Focus on thick plasmas

    NASA Astrophysics Data System (ADS)

    Rezaei, Fatemeh; Tavassoli, Seyed Hassan

    2016-11-01

    In this paper, a study is performed on the spectral lines of plasma radiations created from focusing of the Nd:YAG laser on Al standard alloys at atmospheric air pressure. A new theoretical method is presented to investigate the evolution of the optical depth of the plasma based on the radiative transfer equation, in LTE condition. This work relies on the Boltzmann distribution, lines broadening equations, and as well as the self-absorption relation. Then, an experimental set-up is devised to extract some of plasma parameters such as temperature from modified line ratio analysis, electron density from Stark broadening mechanism, line intensities of two spectral lines in the same order of ionization from similar species, and the plasma length from the shadowgraphy section. In this method, the summation and the ratio of two spectral lines are considered for evaluation of the temporal variations of the plasma parameters in a LIBS homogeneous plasma. The main advantage of this method is that it comprises the both of thin and thick laser induced plasmas without straight calculation of self-absorption coefficient. Moreover, the presented model can also be utilized for evaluation the transition of plasma from the thin condition to the thick one. The results illustrated that by measuring the line intensities of two spectral lines at different evolution times, the plasma cooling and the growth of the optical depth can be followed.

  13. Utilization of Optical Coherence Tomography in the Evaluation of Cherry Hemangiomas.

    PubMed

    Aldahan, Adam S; Mlacker, Stephanie; Shah, Vidhi V; Chen, Lucy L; Nouri, Keyvan; Grichnik, James M

    2016-06-01

    Cherry hemangiomas are common vascular proliferative lesions that can be concerning from a cosmetic perspective. Laser therapy is often used to eradicate cherry hemangiomas, but some lesions require multiple treatments or do not resolve at all. The suboptimal response to laser treatment may be due to limitations in penetration depth by vascular lasers such as the pulsed dye laser. Optical coherence tomography is a low-energy, light-based imaging device that can evaluate the depth and extent of vascular lesions such as cherry hemangiomas by allowing visualization of tissue structure and blood vessel architecture, which cannot be appreciated by clinical or dermatoscopic examination alone. We present optical coherence tomography images of a cherry hemangioma to demonstrate the precision and resolution of this imaging modality. Optical coherence tomography provides valuable information that has the potential to predict response to laser therapy without unnecessary attempts. Future prospective studies will determine its value for this purpose.

    J Drugs Dermatol. 2016;15(6):713-714.

  14. A novel beam optics concept in a particle therapy gantry utilizing the advantages of superconducting magnets.

    PubMed

    Gerbershagen, Alexander; Meer, David; Schippers, Jacobus Maarten; Seidel, Mike

    2016-09-01

    A first order design of the beam optics of a superconducting proton therapy gantry beam is presented. The possibilities of superconducting magnets with respect to the beam optics such as strong fields, large apertures and superposition of different multipole fields have been exploited for novel concepts in a gantry. Since various techniques used in existing gantries have been used in our first design steps, some examples of the existing superconducting gantry designs are described and the necessary requirements of such a gantry are explained. The study of a gantry beam optics design is based on superconducting combined function magnets. The simulations have been performed in first order with the conventional beam transport codes. The superposition of strong dipole and quadrupole fields generated by superconducting magnets enables the introduction of locally achromatic bending sections without increasing the gantry size. A rigorous implementation of such beam optics concepts into the proposed gantry design dramatically increases the momentum acceptance compared to gantries with normal conducting magnets. In our design this large acceptance has been exploited by the implementation of a degrader within the gantry and a potential possibility to use the same magnetic field for all energies used in a treatment, so that the superconducting magnets do not have to vary their fields during a treatment. This also enables very fast beam energy changes, which is beneficial for spreading the Bragg peak over the thickness of the tumor. The results show an improvement of its momentum acceptance. Large momentum acceptance in the gantry creates a possibility to implement faster dose application techniques. Copyright © 2016. Published by Elsevier GmbH.

  15. Defining personal utility in genomics: A Delphi study.

    PubMed

    Kohler, J; Turbitt, E; Lewis, K L; Wilfond, B S; Jamal, L; Peay, H L; Biesecker, L G; Biesecker, B B

    2017-02-20

    Individual genome sequencing results are valued by patients in ways distinct from clinical utility. Such outcomes have been described as components of "personal utility," a concept that broadly encompasses patient-endorsed benefits, that is operationally defined as non-clinical outcomes. No empirical delineation of these outcomes has been reported. To address this gap, we administered a Delphi survey to adult participants in a NIH clinical exome study to extract the most highly endorsed outcomes constituting personal utility. Forty research participants responded to a Delphi survey to rate 35 items identified by a systematic literature review of personal utility. Two rounds of ranking resulted in 24 items that represented 14 distinct elements of personal utility. Elements most highly endorsed by participants were: increased self-knowledge, knowledge of "the condition," altruism, and anticipated coping. Our findings represent the first systematic effort to delineate elements of personal utility that may be used to anticipate participant expectation and inform genetic counseling prior to sequencing. The 24 items reported need to be studied further in additional clinical genome sequencing studies to assess generalizability in other populations. Further research will help to understand motivations and to predict the meaning and use of results.

  16. Optical mosaic method for orthogonally crossed gratings by utilizing information about both main periodic directions simultaneously

    NASA Astrophysics Data System (ADS)

    Zhou, Hengyan; Zeng, Lijiang

    2017-02-01

    We present a method to make optical mosaic orthogonally crossed gratings by utilizing information about both main periodic directions simultaneously. The whole mosaic system for orthogonally crossed gratings is set up based on the dual Lloyd's mirror interferometer that fabricates orthogonally crossed gratings through a single exposure. The interference fringes formed by the diffractions of the exposure beams from the exposed grating areas are used as the reference to fine tune the position and attitude of the exposure beams relative to the substrates during consecutive exposures. A procedure to make mosaic for two main periodic directions simultaneously is proposed based on the presupposition that the angle between two sets of main lattice lines is constant during the mosaic. Experimentally we made a 2×1 mosaic crossed grating with a period of 574 nm in (30+30) mm ×35 mm area. The peak-valley errors of the (-1, 0)th- and (0, -1)st-order diffraction wavefronts over the whole mosaic grating area are 0.104λ and 0.163λ, respectively.

  17. Study on multiple-hops performance of MOOC sequences-based optical labels for OPS networks

    NASA Astrophysics Data System (ADS)

    Zhang, Chongfu; Qiu, Kun; Ma, Chunli

    2009-11-01

    In this paper, we utilize a new study method that is under independent case of multiple optical orthogonal codes to derive the probability function of MOOCS-OPS networks, discuss the performance characteristics for a variety of parameters, and compare some characteristics of the system employed by single optical orthogonal code or multiple optical orthogonal codes sequences-based optical labels. The performance of the system is also calculated, and our results verify that the method is effective. Additionally it is found that performance of MOOCS-OPS networks would, negatively, be worsened, compared with single optical orthogonal code-based optical label for optical packet switching (SOOC-OPS); however, MOOCS-OPS networks can greatly enlarge the scalability of optical packet switching networks.

  18. Diagnostic Utility of Systematic Aquaporin-4 Antibodies Determination in the First Event of Immune-Mediated Optic Neuritis.

    PubMed

    Carnero Contentti, Edgar; De Virgiliis, Mariana; Hryb, Javier Pablo; Leguizamon, Felisa; Celso, Julia; Di Pace, José Luis; Perassolo, Mónica

    2016-01-01

    Antibodies against aquaporin-4 (AQP4-ab) have diagnostic and prognostic value. However, little is known to date about their utility in the first event of optic neuritis (ON). To evaluate the utility of systematic AQP4-ab determination in a retrospective cohort of patients with a first onset of ON. All patients (n = 42) were tested for AQP4-ab in the following context: typical ON (TON) and atypical ON (AON). Clinical, radiological and biochemical data were collected; patients with TON vs. AON and AQP4-ab positive vs. negative were compared. The proportion of AQP4-ab seropositive patients was 40% in the TON group vs. 40.9% in the AON group. Visual acuity (VA) at baseline was poor in AON patients (p = 0.02) and these patients were associated with worse VA outcome (p < 0.001) at 6 months compared with TON patients, with a median follow-up of 3.27 ± 1.79 years. Brain MRI with dissemination in space criteria (p < 0.001), spinal cord partial lesions (p < 0.001) and oligoclonal bands (p = 0.02) were associated with the initial stages of TON. VA severity, number of myelitis attacks and ON relapses did not differ significantly between seropositive and seronegative patients. AQP4-ab were detected only in neuromyelitis optica spectrum disorders patients. This study showed a high seropositivity for AQP4-ab in TON patients, suggesting that it could diagnostic utility at the onset of ON. © 2016 S. Karger AG, Basel.

  19. The Realization and Study of Optical Wings

    NASA Astrophysics Data System (ADS)

    Artusio-Glimpse, Alexandra Brae

    Consider the airfoil: a carefully designed structure capable of stable lift in a uniform air flow. It so happens that air pressure and radiation (light) pressure are similar phenomena because each transfer momentum to flow-disturbing objects. This, then, begs the question: does an optical analogue to the airfoil exist? Though an exceedingly small effect, scientists harness radiation pressure in a wide gamut of applications from micromanipulation of single biological particles to the propulsion of large spacecrafts called solar sails. We introduce a cambered, refractive rod that is subjected to optical forces analogous to those seen in aerodynamics, and I call this analogue the optical wing. Flight characteristics of optical wings are determined by wing shape and material in a uniform radiation field. Theory predicts the lift force and axial torque are functions of the wing's angle of attack with stable and unstable orientations. These structures can operate as intensity-dependent, parametrically driven oscillators. In two-dimensions, the wings exhibit bistability when analyzed in an accelerating frame. In three-dimensions, the motion of axially symmetric spinning hemispherical wings is analogous to a spinning top. Experiments on semi-buoyant wings in water found semicylindrically shaped, refractive microparticles traversed a laser beam and rotated to an illumination-dependent stable orientation. Preliminary tests aid in the development of a calibrated force measurement experiment to directly evaluate the optical forces and torque on these samples. A foundational study of the optical wing, this work contributes to future advancements of flight-by-light.

  20. Capacity Utilization Study for Aviation Security Cargo Inspection Queuing System

    SciTech Connect

    Allgood, Glenn O; Olama, Mohammed M; Lake, Joe E; Brumback, Daryl L

    2010-01-01

    In this paper, we conduct performance evaluation study for an aviation security cargo inspection queuing system for material flow and accountability. The queuing model employed in our study is based on discrete-event simulation and processes various types of cargo simultaneously. Onsite measurements are collected in an airport facility to validate the queuing model. The overall performance of the aviation security cargo inspection system is computed, analyzed, and optimized for the different system dynamics. Various performance measures are considered such as system capacity, residual capacity, throughput, capacity utilization, subscribed capacity utilization, resources capacity utilization, subscribed resources capacity utilization, and number of cargo pieces (or pallets) in the different queues. These metrics are performance indicators of the system s ability to service current needs and response capacity to additional requests. We studied and analyzed different scenarios by changing various model parameters such as number of pieces per pallet, number of TSA inspectors and ATS personnel, number of forklifts, number of explosives trace detection (ETD) and explosives detection system (EDS) inspection machines, inspection modality distribution, alarm rate, and cargo closeout time. The increased physical understanding resulting from execution of the queuing model utilizing these vetted performance measures should reduce the overall cost and shipping delays associated with new inspection requirements.

  1. Capacity utilization study for aviation security cargo inspection queuing system

    NASA Astrophysics Data System (ADS)

    Allgood, Glenn O.; Olama, Mohammed M.; Lake, Joe E.; Brumback, Daryl

    2010-04-01

    In this paper, we conduct performance evaluation study for an aviation security cargo inspection queuing system for material flow and accountability. The queuing model employed in our study is based on discrete-event simulation and processes various types of cargo simultaneously. Onsite measurements are collected in an airport facility to validate the queuing model. The overall performance of the aviation security cargo inspection system is computed, analyzed, and optimized for the different system dynamics. Various performance measures are considered such as system capacity, residual capacity, throughput, capacity utilization, subscribed capacity utilization, resources capacity utilization, subscribed resources capacity utilization, and number of cargo pieces (or pallets) in the different queues. These metrics are performance indicators of the system's ability to service current needs and response capacity to additional requests. We studied and analyzed different scenarios by changing various model parameters such as number of pieces per pallet, number of TSA inspectors and ATS personnel, number of forklifts, number of explosives trace detection (ETD) and explosives detection system (EDS) inspection machines, inspection modality distribution, alarm rate, and cargo closeout time. The increased physical understanding resulting from execution of the queuing model utilizing these vetted performance measures should reduce the overall cost and shipping delays associated with new inspection requirements.

  2. Feasibility Study for a Hopi Utility-Scale Wind Project

    SciTech Connect

    Kendrick Lomayestewa

    2011-05-31

    The goal of this project was to investigate the feasibility for the generation of energy from wind and to parallel this work with the development of a tribal utility organization capable of undertaking potential joint ventures in utility businesses and projects on the Hopi reservation. The goal of this project was to investigate the feasibility for the generation of energy from wind and to parallel this work with the development of a tribal utility organization capable of undertaking potential joint ventures in utility businesses and projects on the Hopi reservation. Wind resource assessments were conducted at two study sites on Hopi fee simple lands located south of the city of Winslow. Reports from the study were recently completed and have not been compared to any existing historical wind data nor have they been processed under any wind assessment models to determine the output performance and the project economics of turbines at the wind study sites. Ongoing analysis of the wind data and project modeling will determine the feasibility of a tribal utility-scale wind energy generation.

  3. Nonlinear optical techniques for surface studies. [Monolayers

    SciTech Connect

    Shen, Y.R.

    1981-09-01

    Recent effort in developing nonlinear optical techniques for surface studies is reviewed. Emphasis is on monolayer detection of adsorbed molecules on surfaces. It is shown that surface coherent antiStokes Raman scattering (CARS) with picosecond pulses has the sensitivity of detecting submonolayer of molecules. On the other hand, second harmonic or sum-frequency generation is also sensitive enough to detect molecular monolayers. Surface-enhanced nonlinear optical effects on some rough metal surfaces have been observed. This facilitates the detection of molecular monolayers on such surfaces, and makes the study of molecular adsorption at a liquid-metal interface feasible. Advantages and disadvantages of the nonlinear optical techniques for surface studies are discussed.

  4. Lithium niobate-based integrated optic chip utilizing digital electrode layout for use in a miniature fiber optic rate sensor

    NASA Astrophysics Data System (ADS)

    Ner, Manjeet S.; Kemmler, Manfred W.; Spahlinger, Guenter

    1996-11-01

    This paper describes to the best of our knowledge the first implementation of a Lithium Niobate based 8 bit electroded integrated optic waveguide fiber optic gyro chip referred here to as 'Digi-MIOC', which has been used in a Sagnac effect exploiting micro fiber optic rate sensor ((mu) -FORS) developed by LITEF. The paper highlights various features of a Digi-MIOC, such as design philosophy, fabrication aspects, and test procedures to evaluate static and dynamic characteristics of the electro-optic parameters. As a consequence of this work, it has been possible for LITEF to cost effectively mass produce Digi-MIOCs. When used in closed loop operation, the Digi-MIOC forms the key optical component of a (mu) -FORS to aid the required optical-to- electrical signal processing to give linear output for input rates of rotation. Various test results and features of LITEF's (mu) -FORS, such as small size, large rotation rate measurement potential, low drive power and high reliability are also highlighted.

  5. Structural and Function Correlation of Cone Packing Utilizing Adaptive Optics and Microperimetry

    PubMed Central

    Supriya, Dabir; Shwetha, Mangalesh; Kiran Anupama, Kumar; Kummelil Mathew, Kurian; Berendschot, Tos T. J. M.; Schouten, Jan S. A. G.; Bharamshetter, Roopa; Naresh, Yadav K.; Rohit, Shetty; Hegde, Bharath

    2015-01-01

    Aim. To assess the functional aspects of cone mosaic and correlate cone packing with retinal sensitivity utilizing microperimetry in emmetropes at different eccentricities. Methods. Twenty-four healthy volunteers underwent microperimetry (MAIA Centervue, Italy) and assessment of photoreceptors using adaptive optics retinal camera, rtx1 (Imagine Eyes, Orsay, France), at 2 and 3 degrees from the foveal centre in 4 quadrants: superior, inferior, temporal, and nasal. Data was analyzed using SPSS version 17 (IBM). Spearman's correlation tests were used to establish correlation between mean cone packing density and retinal sensitivity at different quadrants. Results. Thirteen females and 11 males (age range 20–40 years) were included. The cone density was found to be significantly different among all quadrants (temporal = 25786.68/mm2 ± 4367.07/mm2, superior = 23009.35/mm2 ± 5415.81/mm2, nasal = 22838.09/mm2 ± 4166.22/mm2, and inferior = 21097.53/mm2 ± 4235.84/mm2). A statistical significance (P < 0.008) was found between orthogonal meridians, that is, temporal, nasal (48624.77/mm2)> superior, inferior (44106.88/mm2). A drop in retinal sensitivity was observed as the eccentricity increased (P < 0.05). It was also found that as cone packing density decreased retinal sensitivity also decreased (P < 0.05) in all quadrants. This was observed at both 2 and 3 degrees. Conclusion. It is of crucial importance to establish normative variations in cone structure-function correlation. This may help in detection of subtle pathology and its early intervention. PMID:26167509

  6. Health service utilization of heroin abusers: a retrospective cohort study.

    PubMed

    Chen, I-Ming; Huang, Charles Lung-Cheng; Yeh, Bao-Juan; Chien, Yi-Ling

    2015-06-01

    This study aimed to determine the patterns of medical service utilization among heroin users and to identify the factors associated with the frequency of utilization. We conducted a retrospective/prospective cohort study of 789 heroin-using adults in a catchment area, collecting data on their usage of medical care, including inpatient care, emergency visits, and outpatient care, in a 2-year observation period. We interviewed and reviewed the medical records of 789 heroin users in a methadone clinic of a general hospital in a rural area of Taiwan. The demographic data, records of service use, diagnoses, and information on viral infection status from Jan. 1, 2007 to Dec. 31, 2008 were collected. Most patients were middle-aged and unemployed, had a basic educational level, and began their first heroin use in their twenties. The health service utilization of heroin users was mostly for infectious diseases, orthopedic conditions, and gastroenterological disorders mainly due to blood-borne or local infections and traumatic injury. Heroin users utilize fewer outpatient or inpatient services, but more emergency care than the general public. The major correlates of inpatient and emergency service utilization were HIV status and education level. Our findings suggest that integrated outpatient services may help to enhance medical service accessibility and adherence, and also imply the necessity of putting more effort into promoting health management and safe behaviors in heroin users, particularly the lower-educated addicts. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Utilizing optical coherence tomography for CAD/CAM of indirect dental restorations

    NASA Astrophysics Data System (ADS)

    Chityala, Ravishankar; Vidal, Carola; Jones, Robert

    Optical Coherence Tomography (OCT) has seen broad application in dentistry including early carious lesion detection and imaging defects in resin composite restorations. This study investigates expanding the clinical usefulness by investigating methods to use OCT for obtaining three-dimensional (3D) digital impressions, which can be integrated to CAD/CAM manufacturing of indirect restorations. 3D surface topography `before' and `after' a cavity preparation was acquired by an intraoral cross polarization swept source OCT (CP-OCT) system with a Micro-Electro-Mechanical System (MEMS) scanning mirror. Image registration and segmentation methods were used to digitally construct a replacement restoration that modeled the original surface morphology of a hydroxyapatite sample. After high resolution additive manufacturing (e.g. polymer 3D printing) of the replacement restoration, micro-CT imaging was performed to examine the marginal adaptation. This study establishes the protocol for further investigation of integrating OCT with CAD/CAM of indirect dental restorations.

  8. A Space Utilization Study at Gaston College: Methodology and Procedures.

    ERIC Educational Resources Information Center

    Hall, Pam; Clay, Rex

    In fall 1995, North Carolina's Gaston College undertook a study of space utilization at the college's main campus. A local architectural firm was contracted to document the exact usage of space on campus, establish space requirements to meet present circumstances, and identify future needs. To determine current usage, plots of current and original…

  9. Investigation of utilizing a VCSEL diode to work as a tunable optical bandpass filter

    NASA Astrophysics Data System (ADS)

    Chang, Ching-Hung; Huang, Yi-Syuan; Li, Chung-Yi

    2017-04-01

    Tunable optical band-pass filter (TOBPF) composed of a vertical-cavity surface-emitting laser (VCSEL) is proposed for multi-wavelength optical fiber transport systems. Experimental results prove that through properly adjusting VCSEL driving current, one of multiple injected lightwaves can properly flow through the proposed optical filter and others will be attenuated roughly 12 dB. Furthermore, by changing the VCSEL driving current, the pass-band window of the VCSEL-based TOBPF can be shifted to align with different designated injected lightwave and to block the others. By employing the TOBPF in multi-wavelength optical fiber transport systems, proper eye diagrams are experimentally observed for each dedicated optical signal. The proposed scheme is shown to be a practical and flexible component for multi-wavelength optical fiber transport systems.

  10. Design and evaluation of an optical fine-pointing control system for telescopes utilizing a digital star sensor

    NASA Technical Reports Server (NTRS)

    Ostroff, A. J.; Romanczyk, K. C.

    1973-01-01

    One of the most significant problems associated with the development of large orbiting astronomical telescopes is that of maintaining the very precise pointing accuracy required. A proposed solution to this problem utilizes dual-level pointing control. The primary control system maintains the telescope structure attitude stabilized within the field of view to the desired accuracy. In order to demonstrate the feasibility of optically stabilizing the star images to the desired accuracy a regulating system has been designed and evaluated. The control system utilizes a digital star sensor and an optical star image motion compensator, both of which have been developed for this application. These components have been analyzed mathematically, analytical models have been developed, and hardware has been built and tested.

  11. Nonlinear optical studies of organic monolayers

    SciTech Connect

    Shen, Y.R.

    1988-02-01

    Second-order nonlinear optical effects are forbidden in a medium with inversion symmetry, but are necessarily allowed at a surface where the inversion summary is broken. They are often sufficiently strong so that a submonolayer perturbation of the surface can be readily detected. They can therefore be used as effective tools to study monolayers adsorbed at various interfaces. We discuss here a number of recent experiments in which optical second harmonic generation (SHG) and sum-frequency generation (SFG) are employed to probe and characterize organic monolayers. 15 refs., 5 figs.

  12. Ground-source heat pump case studies and utility programs

    SciTech Connect

    Lienau, P.J.; Boyd, T.L.; Rogers, R.L.

    1995-04-01

    Ground-source heat pump systems are one of the promising new energy technologies that has shown rapid increase in usage over the past ten years in the United States. These systems offer substantial benefits to consumers and utilities in energy (kWh) and demand (kW) savings. The purpose of this study was to determine what existing monitored data was available mainly from electric utilities on heat pump performance, energy savings and demand reduction for residential, school and commercial building applications. In order to verify the performance, information was collected for 253 case studies from mainly utilities throughout the United States. The case studies were compiled into a database. The database was organized into general information, system information, ground system information, system performance, and additional information. Information was developed on the status of demand-side management of ground-source heat pump programs for about 60 electric utility and rural electric cooperatives on marketing, incentive programs, barriers to market penetration, number units installed in service area, and benefits.

  13. Tumor functional and molecular imaging utilizing ultrasound and ultrasound-mediated optical techniques.

    PubMed

    Yuan, Baohong; Rychak, Joshua

    2013-02-01

    Tumor functional and molecular imaging has significantly contributed to cancer preclinical research and clinical applications. Among typical imaging modalities, ultrasonic and optical techniques are two commonly used methods; both share several common features such as cost efficiency, absence of ionizing radiation, relatively inexpensive contrast agents, and comparable maximum-imaging depth. Ultrasonic and optical techniques are also complementary in imaging resolution, molecular sensitivity, and imaging space (vascular and extravascular). The marriage between ultrasonic and optical techniques takes advantages of both techniques. This review introduces tumor functional and molecular imaging using microbubble-based ultrasound and ultrasound-mediated optical imaging techniques.

  14. Studying Charged Particle Optics: An Undergraduate Course

    ERIC Educational Resources Information Center

    Ovalle, V.; Otomar, D. R.; Pereira, J. M.; Ferreira, N.; Pinho, R. R.; Santos A. C. F.

    2008-01-01

    This paper describes some computer-based activities to bring the study of charged particle optics to undergraduate students, to be performed as a part of a one-semester accelerator-based experimental course. The computational simulations were carried out using the commercially available SIMION program. The performance parameters, such as the focal…

  15. Studying Charged Particle Optics: An Undergraduate Course

    ERIC Educational Resources Information Center

    Ovalle, V.; Otomar, D. R.; Pereira, J. M.; Ferreira, N.; Pinho, R. R.; Santos A. C. F.

    2008-01-01

    This paper describes some computer-based activities to bring the study of charged particle optics to undergraduate students, to be performed as a part of a one-semester accelerator-based experimental course. The computational simulations were carried out using the commercially available SIMION program. The performance parameters, such as the focal…

  16. Survivable wavelength-division multiplexing passive optical network system with centralized protection routing scheme and efficient wavelength utilization

    NASA Astrophysics Data System (ADS)

    Zhou, Zhao; Xiao, Shilin; Bi, Meihua; Qi, Tao; Li, Pingqing; Hu, Weisheng

    2013-09-01

    A survivable wavelength-division multiplexing passive optical network (WDM-PON) with centralized protection scheme and colorless optical network units is proposed. The sideband channels generated via optical carrier suppression technique are used to carry both the downstream (DS) and the upstream (US) remodulated signals for two neighboring sub-PONs. By employing alternate path routing of sideband channels, the centralized protection scheme can provide reliable protection against any failure in feed fibers, remote node, and distribution fibers. The number of extra fibers is greatly reduced, and efficient utilization of wavelength resource is achieved. The feasibility of the proposed system is verified by 10-Gb/s DS and 1.25-Gb/s US signals over 25-km single-mode fiber transmission in both working and protection modes.

  17. Studies on effective utilization of precipitates from neutralized mine drainage

    SciTech Connect

    Harada, Taneomi

    1995-12-31

    Mine drainage has high acidity and sometimes contains more than the allowable concentration of ionized iron. In such a case, mine drainage is neutralized with calcium carbonate and calcium hydroxide to separate precipitates, such as the iron hydroxide and gypsum generated. Currently, most of these precipitates are not utilized and are accumulated in tailing dams. As a result, the service life of the tailing dams is reduced. This becomes a matter of concern, since securing sites for such dams is difficult. A most effective means of solving this problem would be to promote utilization of these neutralized precipitates. This paper reports on the results of studies on neutralized precipitates produced at the old Matsuo Mine (Iwate Prefecture), which has the largest neutralization treatment facility in Japan. As a result of the studies, the following was proposed regarding application of neutralized precipitates. Utilization as ferrite: mix ferrous hydroxide and ferric hydroxide in water to synthesize magnetite-like ferrite, to be used in the manufacture of magnetic markers for a mobility support system for blind pedestrians, or in producing magnetic fluids for sink-and-float separation of nonmagnetic metals and nonmetals. Utilization as hematite: bake ferric hydroxide to produce hematite, thereby extracting metallic iron for paint pigment as well as for the manufacture of ironware by local industry. Production of aluminum sulfate: precipitate aluminum ions from water and add sulfuric acid to produce aluminum sulfate.

  18. Socioeconomic factors, morbidity and drug utilization--an ecological study.

    PubMed

    Henricson, K; Stenberg, P; Rametsteiner, G; Ranstam, J; Hanson, B S; Melander, A

    1998-07-01

    The aim of the present study was to elucidate the relations between demographic and socioeconomic factors, morbidity and the utilization of major drug groups in an urban Swedish population. The study was performed as an ecological analysis during November 1991 in the 17 different districts of Malmö, the third largest Swedish city (235,000 inhabitants). The material comprised 86,228 ACT-coded drug items which corresponded to 76% of all prescriptions dispensed during the study month. Of these, 43,032, dispensed to patients aged 15-64 years, were analysed in the present work. Age standardized drug utilization was expressed as the number of dispensed Defined Daily Doses per 1000 inhabitants per day. Morbidity was measured in terms of reimbursed days on sick leave. The sociodemographic parameters used were socioeconomic status (SES), employment rate, median income per family, households on social allowance, and ethnicity. For four of the five major pharmacological groups (ATC-groups A, C, J, N and R, i.e. alimentation, circulation, infectious diseases, nervous system and respiration), most pronouncedly group N and least so group R, utilization correlated positively with not only the extent of morbidity but also with an unfavourable socioeconomic situation, high proportion of immigrants, and households on social allowance or with low income and/or with a low employment rate. The utilization of antibiotics (group J), however, instead correlated negatively with these parameters. For all five drug groups, these trends were similar among men and women, albeit with varying strength. In conclusion, socioeconomic factors may have a profound influence on the utilization of several major drug groups. At least in the case of antibiotics, the consequence of this influence is irrational drug use.

  19. Optical alignment procedure utilizing neural networks combined with Shack-Hartmann wavefront sensor

    NASA Astrophysics Data System (ADS)

    Adil, Fatime Zehra; Konukseven, Erhan İlhan; Balkan, Tuna; Adil, Ömer Faruk

    2017-05-01

    In the design of pilot helmets with night vision capability, to not limit or block the sight of the pilot, a transparent visor is used. The reflected image from the coated part of the visor must coincide with the physical human sight image seen through the nonreflecting regions of the visor. This makes the alignment of the visor halves critical. In essence, this is an alignment problem of two optical parts that are assembled together during the manufacturing process. Shack-Hartmann wavefront sensor is commonly used for the determination of the misalignments through wavefront measurements, which are quantified in terms of the Zernike polynomials. Although the Zernike polynomials provide very useful feedback about the misalignments, the corrective actions are basically ad hoc. This stems from the fact that there exists no easy inverse relation between the misalignment measurements and the physical causes of the misalignments. This study aims to construct this inverse relation by making use of the expressive power of the neural networks in such complex relations. For this purpose, a neural network is designed and trained in MATLAB® regarding which types of misalignments result in which wavefront measurements, quantitatively given by Zernike polynomials. This way, manual and iterative alignment processes relying on trial and error will be replaced by the trained guesses of a neural network, so the alignment process is reduced to applying the counter actions based on the misalignment causes. Such a training requires data containing misalignment and measurement sets in fine detail, which is hard to obtain manually on a physical setup. For that reason, the optical setup is completely modeled in Zemax® software, and Zernike polynomials are generated for misalignments applied in small steps. The performance of the neural network is experimented and found promising in the actual physical setup.

  20. MO-F-CAMPUS-T-04: Utilization of Optical Dosimeter for Modulated Spot-Scanning Particle Beam

    SciTech Connect

    Hsi, W; Li, Y; Huang, Z; Sheng, Y; Deng, Y; Zhao, J; Zhao, F; Sun, L; Moyers, M

    2015-06-15

    Purpose: To present the utilization of an optical dosimeter for modulated spot-scanning carbon-ion and proton beams during the acceptance test of Siemens IONTRIS system. Method and Materials: An optical dosimeter using phosphor scintillation was developed to map and interactively analyze the shapes and sizes of spots over 190 energies for ProTom modulated-scanning system. The dose response to proton had been characterized with proper pixel calibration at ProTom system. The dose response was further studied at 0.7 cm depths by uniform 8cm in-diameter fields of 424.89 MeV/u (E290) carbon-ions and 215.18MeV (E282) protons at IONTRIS system. The virtual source axial distances (vSAD) of carbonions and protons of IONTRIS system was investigated by measuring either variations of spot position or field size at five different locations to Isocenter. By measuring lateral profiles of uniform doses with varied thin-thicknesses of chest-board pattern and placing the scintillation plate at near to the distal edge, range variations at different off-axis-distances (rOAD) were examined. Relative accuracy and reproducibility of beam range were measured for three beam ranges with a ramping block at front of scintillation plate. Results: Similar dose response was observed for high energies of carbon ions and protons. Mean vSAD at X and Y axes were 744.1 cm and 807.4cm with deviation of 7.4cm and 7.7cm, respectively. Variation of rOAD was within 0.35 mm over 10cm for both protons and carbon ions. Accuracy of measuring relative distal range using the ramping block was 0.2mm. Measured range over repeated three times for each range were within 0.25mm at same room, and within 1.0mm between four rooms. Conclusions: The optical dosimeter could efficiently measure the virtual source distance. And, to measure small range variation at different off-axial locations, and for the relative beam range between rooms during acceptance test of a modulated spot-scanning particle system.

  1. Boosting workplace stair utilization: a study of incremental reinforcement.

    PubMed

    Schumacher, Joseph E; Utley, Janice; Sutton, Lindsay; Horton, Trudi; Hamer, Trey; You, Zhiying; Klapow, Joshua C

    2013-02-01

    This study was designed to determine whether engagement in stair taking can be increased in a worksite setting through the provision of an employer-sponsored, behavior-based incentive system in which employees (members) accumulate points that can be redeemed for merchandise. ChipRewards implemented stair utilization in one employer as a part of a larger health incentive engagement program. Using an AB (baseline-intervention) design, members (N = 216) were observed for 6 months (6.17.10 to 12.14.10 or 129 weekdays after excluding 52 weekend days) before the intervention (baseline) and after 6 months (1.1.11 to 6.30.11 with the same number of weekdays) of implementation. Members were 84% female, 51% Caucasian, 48% African American, 3% Hispanic, and 45 years average age. The number of total stair transactions for all members for all days monitored increased from 5,070 to 38,900, and the average number of stair transactions per day rose from 39 to 301, representing over a 600% increase. The overall cost of incentives for stair utilization was $3,739.30 or $17.55 per member on average. This study supports that stair usage in the workplace is a viable way to increase physical activity. This study adds to existing research that attempted to increase stair utilization through promotion only by adding a behavioral reinforcement strategy. Finally, this study demonstrates that a physical activity among employees at the worksite can be increased with minimal relative cost.

  2. Comparative study between the reflective optics and lens based system for microwave imaging system on KSTAR

    SciTech Connect

    Lee, W.; Yun, G. S.; Nam, Y.; Hong, I.; Kim, J. B.; Park, H. K.; Tobias, B.; Liang, T.; Domier, C. W.; Luhmann, N. C. Jr.

    2010-10-15

    Recently, two-dimensional microwave imaging diagnostics such as the electron cyclotron emission imaging (ECEI) system and microwave imaging reflectometry (MIR) have been developed to study magnetohydrodynamics instabilities and turbulence in magnetically confined plasmas. These imaging systems utilize large optics to collect passive emission or reflected radiation. The design of this optics can be classified into two different types: reflective or refractive optical systems. For instance, an ECEI/MIR system on the TEXTOR tokamak [Park et al., Rev. Sci. Instrum. 75, 3787 (2004)] employed the reflective optics which consisted of two large mirrors, while the TEXTOR ECEI upgrade [B. Tobias et al., Rev. Sci. Instrum. 80, 093502 (2009)] and systems on DIII-D, ASDEX-U, and KSTAR adopted refractive systems. Each system has advantages and disadvantages in the standing wave problem and optical aberrations. In this paper, a comparative study between the two optical systems has been performed in order to design a MIR system for KSTAR.

  3. Study of Lyndon B. Johnson Space Center utility systems

    NASA Technical Reports Server (NTRS)

    Redding, T. E.; Huber, W. C.

    1977-01-01

    The results of an engineering study of potential energy saving utility system modifications for the NASA Lyndon B. Johnson Space Center are presented. The objective of the study was to define and analyze utility options that would provide facility energy savings in addition to the approximately 25 percent already achieved through an energy loads reduction program. A systems engineering approach was used to determine total system energy and cost savings resulting from each of the ten major options investigated. The results reported include detailed cost analyses and cost comparisons of various options. Cost are projected to the year 2000. Also included are a brief description of a mathematical model used for the analysis and the rationale used for a site survey to select buildings suitable for analysis.

  4. Near-field enhanced optical tweezers utilizing femtosecond-laser nanostructured substrates

    SciTech Connect

    Kotsifaki, D. G. Kandyla, M.; Lagoudakis, P. G.

    2015-11-23

    We present experimental evidence of plasmonic-enhanced optical tweezers, of polystyrene beads in deionized water in the vicinity of metal-coated nanostructures. The optical tweezers operate with a continuous wave near-infrared laser. We employ a Cu/Au bilayer that significantly improves dissipation of heat generated by the trapping laser beam and avoid de-trapping from heat convection currents. We investigate the improvement of the optical trapping force and the effective trapping quality factor, and observe an exponential distance dependence of the trapping force from the nanostructures, indicative of evanescent plasmonic enhancement.

  5. A high pressure optical cell utilizing single crystal cubic zirconia anvil windows

    NASA Astrophysics Data System (ADS)

    Russell, T. P.; Piermarini, G. J.

    1997-04-01

    A high pressure optical cell capable of producing pressures up to 13.2 GPa using gem-cut single crystal cubic zirconia (CZ) anvils was developed. Maximum pressures obtainable were found to depend upon the particular pressure transmitting medium and gasket material employed. The cubic zirconia anvil high pressure cell (CZAC) provides advantages over the diamond anvil cell in optical and infrared spectroscopy while still maintaining a substantial pressure capability. To demonstrate these advantages, microRaman, optical fluorescence, and infrared absorption measurements were made on diamond, ruby, and 1,3,5-trinitrohexahydro-1,3,5-triazine samples, respectively, using the CZAC cell under high pressure conditions.

  6. Near-field enhanced optical tweezers utilizing femtosecond-laser nanostructured substrates

    NASA Astrophysics Data System (ADS)

    Kotsifaki, D. G.; Kandyla, M.; Lagoudakis, P. G.

    2015-11-01

    We present experimental evidence of plasmonic-enhanced optical tweezers, of polystyrene beads in deionized water in the vicinity of metal-coated nanostructures. The optical tweezers operate with a continuous wave near-infrared laser. We employ a Cu/Au bilayer that significantly improves dissipation of heat generated by the trapping laser beam and avoid de-trapping from heat convection currents. We investigate the improvement of the optical trapping force and the effective trapping quality factor, and observe an exponential distance dependence of the trapping force from the nanostructures, indicative of evanescent plasmonic enhancement.

  7. Simultaneous optical and radar observations of meteor head-echoes utilizing SAAMER

    NASA Astrophysics Data System (ADS)

    Michell, R. G.; Janches, D.; Samara, M.; Hormaechea, J. L.; Brunini, C.; Bibbo, I.

    2015-12-01

    We present simultaneous optical and radar observations of meteors observed with the Southern Argentine Agile MEteor Radar (SAAMER). Although such observations were performed in the past using High Power and Large Aperture radars, the focus here is on meteors that produced head echoes that can be detected by a significantly less sensitive but more accessible radar system. An observational campaign was conducted in August of 2011, where an optical imager was operated near the radar site in Rio Grande, Tierra del Fuego, Argentina. Six head echo events out of 150 total detections were identified where simultaneous optical meteors could also be clearly seen within the main radar beam. The location of the meteors derived from the radar interferometry agreed very well with the optical location, verifying the accuracy of the radar interferometry technique. The meteor speeds and origin directions calculated from the radar data were accurate-compared with the optics-for the 2 meteors that had radar signal-to-noise ratios above 2.5. The optical meteors that produced the head echoes had horizontal velocities in the range of 29-91 km/s. These comparisons with optical observations improve the accuracy of the radar detection and analysis techniques, such that, when applied over longer periods of time, will improve the statistics of southern hemisphere meteor observations. Mass estimates were derived using both the optical and radar data and the resulting masses agreed well with each other. All were within an order of magnitude and in most cases, the agreement was within a factor of two.

  8. 160 Gb/s OFDM transmission utilizing an all-optical symbol generator based on PLC

    NASA Astrophysics Data System (ADS)

    Liang, Xiaojun; Qiao, Yaojun; Li, Wei; Mei, Junyao; Qin, Yi

    2009-11-01

    We demonstrate a 160 Gb/s orthogonal frequency division multiplexing (OFDM) system using an all-optical symbol generator based on planar light circuit (PLC) technology. Excellent bit error rate (BER) is observed after long-distance transmission. The proposed symbol generator fundamentally eliminates the processing speed limits introduced by electronics and is suitable for high integration, making it physically realizable to build high-speed all-optical OFDM systems with a large number of subcarriers.

  9. Enterprise utilization of "always on-line" diagnostic study archive.

    PubMed

    McEnery, Kevin W; Suitor, Charles T; Thompson, Stephen K; Shepard, Jeffrey S; Murphy, William A

    2002-01-01

    To meet demands for enterprise image distribution, an "always on-line" image storage archive architecture was implemented before soft copy interpretation. It was presumed that instant availability of historical diagnostic studies would elicit a substantial utilization. Beginning November 1, 2000 an enterprise distribution archive was activated (Stentor, SanFrancisco, CA). As of August 8, 2001, 83,052 studies were available for immediate access without the need for retrieval from long-term archive. Image storage and retrieval logs for the period from June 12, 2001 to August 8, 2001 were analyzed. A total of 41,337 retrieval requests were noted for the 83,052 studies available as August 8, 2001. Computed radiography represented 16.8% of retrieval requests; digital radiography, 16.9%; computed tomography (CT), 44.5%; magnetic resonance (MR), 19.2%; and ultrasonography, 2.6%. A total of 51.5% of study retrievals were for studies less than 72 hours old. Study requests for cases greater than 100 days old represented 9.9% of all accessions, 9.7% of CT accessions, and 15.4% of MR accessions. Utilization of the archive indicates a substantial proportion of study retrievals for studies less than 72 hours after study completion. However, significant interest in historical CT and MR examinations was shown.

  10. Hybrid diversity method utilizing adaptive diversity function for recovering unknown aberrations in an optical system

    NASA Technical Reports Server (NTRS)

    Dean, Bruce H. (Inventor)

    2009-01-01

    A method of recovering unknown aberrations in an optical system includes collecting intensity data produced by the optical system, generating an initial estimate of a phase of the optical system, iteratively performing a phase retrieval on the intensity data to generate a phase estimate using an initial diversity function corresponding to the intensity data, generating a phase map from the phase retrieval phase estimate, decomposing the phase map to generate a decomposition vector, generating an updated diversity function by combining the initial diversity function with the decomposition vector, generating an updated estimate of the phase of the optical system by removing the initial diversity function from the phase map. The method may further include repeating the process beginning with iteratively performing a phase retrieval on the intensity data using the updated estimate of the phase of the optical system in place of the initial estimate of the phase of the optical system, and using the updated diversity function in place of the initial diversity function, until a predetermined convergence is achieved.

  11. Optical spectroscopy in turbid media utilizing an integrating sphere: mitochondrial chromophore analysis during metabolic transitions

    PubMed Central

    Chess, David J.; Billings, Eric; Covian, Raúl; Glancy, Brian; French, Stephanie; Taylor, Joni; de Bari, Heather; Murphy, Elizabeth; Balaban, Robert S.

    2013-01-01

    Recent evidence suggests that the activity of mitochondrial oxidative phosphorylation Complexes (MOPC) is modulated at multiple sites. Herein, a method of optically monitoring electron distribution within and between MOPC is described using a center-mounted sample in an integrating sphere (to minimize scattering effects) with a rapid-scanning spectrometer. The redox-sensitive MOPC absorbances (~465 to 630 nm) were modeled using linear least squares analysis with individual chromophore spectra. Classical mitochondrial activity transitions (e.g., ADP-induced increase in oxygen consumption) were used to characterize this approach. Most notable in these studies was the observation that intermediates of the catalytic cycle of cytochrome oxidase are dynamically modulated with metabolic state. The MOPC redox state, along with measurements of oxygen consumption and mitochondrial membrane potential, was used to evaluate the conductances of different sections of the electron transport chain. This analysis then was applied to mitochondria isolated from rabbit hearts subjected to ischemia-reperfusion (I/R). Surprisingly, I/R resulted in an inhibition of all measured MOPC conductances, suggesting a coordinated down-regulation of mitochondrial activity with this well-established cardiac perturbation. PMID:23665273

  12. Patterns of healthcare utilization by COPD severity: a pilot study.

    PubMed

    Joo, Min J; Lee, Todd A; Bartle, Brian; van de Graaff, William B; Weiss, Kevin B

    2008-01-01

    Global Initiative on Chronic Obstructive Lung Disease (GOLD) guidelines recently removed stage 0, a group with symptoms but without airways obstruction, from their severity staging. However, in practice this group may still be diagnosed and medically managed. The aim of this study was to characterize healthcare utilization patterns of chronic obstructive pulmonary disease (COPD) patients by disease severity, focusing on the possible unique attributes of patients who would have been classified as GOLD stage 0. This is a prospective cohort pilot study performed at the Hines Veterans Administration Hospital. One hundred twenty patients with a diagnosis of COPD were enrolled. The participants completed quality-of-life questionnaires and a pulmonary function test. Healthcare utilization data were obtained 1 year prior and 2 years after the enrollment date. Three disease severity groups were defined based on GOLD criteria for comparison [GOLD stage 1-2 (GS 1-2), GOLD stage 3-4 (GS 3-4), and formerly GOLD stage 0 ("at risk")]. The "at risk" group had an average of 14.4 (SD = 30.5) outpatient visits/year and 0.3 (SD = 0.8) hospitalizations/year, which were higher than the other groups, but this was not statistically significant. Respiratory medications were used by 6 (26%), 30 (59%), and 40 (91%) patients from "at risk" to GS 3-4, respectively. Patients in the "at risk" group had a decrement in health status, significant utilization of healthcare services, and were often receiving medications not consistent with guidelines.

  13. Technology Utilization House Study Report. [For Energy Conservation

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The objectives of Project TECH are: (1) to construct a single family detached dwelling for demonstrating the application of advanced technology and minimizing the requirement for energy and utility services, and (2) to help influence future development in home construction by defining the interaction of integrated energy and water management systems with building configuration and construction materials. Components and methods expected to be cost effective over a 20 year span were studied. Emphasis was placed on the utilization of natural heating and cooling characteristics. Orientation and location of windows, landscaping, natural ventilation, and characteristics of the local climate and microclimate were intended to be used to best advantage. Energy conserving homes are most efficient when design for specific sites, therefore project TECH should not be considered a prototype design suitable for all locations. However, it does provide ideas and analytical methods which can be applied to some degree in all housing.

  14. Optical studies of polar stratospheric clouds

    NASA Astrophysics Data System (ADS)

    Enell, Carl-Fredrik; Gustavsson, Bjorn; Steen, Ake; Brandstrom, Urban; Rydesater, Peter; Johansson, P.; Wagner, T.; Friess, U.; Pfeilsticker, K.; Platt, Ulrich

    1999-12-01

    Polar Stratospheric Clouds (PSC) appear in the polar zones of the Earth in the winter. These clouds are known to cause enhanced chemical ozone destruction. Methods for optical remote-sensing of PSC in use or under development at the Swedish Institute of Space Physics are discussed with respect to their advantages and limitations. Especially multistatic imaging may become a valuable additional tool for PSC studies.

  15. Optical Studies of Semiconductor Quantum Dots

    NASA Astrophysics Data System (ADS)

    Yükselici, H.; Allahverdi, Ç.; Aşıkoğlu, A.; Ünlü, H.; Baysal, A.; Çulha, M.; İnce, R.; İnce, A.; Feeney, M.; Athalin, H.

    Optical absorption (ABS), steady-state photoluminescence (PL), resonant Raman, and photoabsorption (PA) spectroscopies are employed to study quantum-size effects in II-VI semiconductor quantum dots (QDs) grown in glass samples. We observe a size-dependent shift in the energetic position of the first exciton peak and have examined the photoinduced evolution of the differential absorption spectra. The Raman shifts of the phonon modes are employed to monitor stoichiometric changes in the composition of the QDs during growth. Two sets of glass samples were prepared from color filters doped with CdS x Se1 - x and Zn x Cd1 - x Te. We analyze the optical properties of QDs through the ABS, PL, resonant Raman, and PA spectroscopies. The glass samples were prepared from commercially available semiconductor doped filters by a two-step thermal treatment. The average size of QDs is estimated from the energetic position of the first exciton peak in the ABS spectrum. A calculation based on a quantized-state effective mass model in the strong confinement regime predicts that the average radius of QDs in the glass samples ranges from 2.9 to 4.9 nm for CdTe and from 2.2 to 9.3 nm for CdS0. 08Se0. 92. We have also studied the nonlinear optical properties of QDs by reviewing the results of size-dependent photoinduced modulations in the first exciton band of CdTe QDs studied by PA spectroscopy.

  16. Scoping study of integrated resource planning needs in the public utility sector

    SciTech Connect

    Garrick, C J; Garrick, J M; Rue, D R

    1993-06-01

    Integrated resource planning (IRP) is an approach to utility resource planning that integrates the evaluation of supply- and demand-site options for providing energy services at the least cost. Many utilities practice IRP; however, most studies about IRP focus on investor-owned utilities (IOUs). This scoping study investigates the IRP activities and needs of public utilities (not-for-profit utilities, including federal, state, municipal, and cooperative utilities). This study (1) profiles IRP-related characteristics of the public utility sector, (2) articulates the needs of public utilities in understanding and implementing IRP, and (3) identifies strategies to advance IRP principles in public utility planning.

  17. Fundamental Study of Low-Nox Combustion Fly Ash Utilization

    SciTech Connect

    E. M. Suuberg; I. Kuloats; K. Smith; N. Sabanegh; R. H. Hurt; W. D. Lilly; Y. M. Gao

    1997-11-01

    This study is principally concerned with characterizing the organic part of coal combustion fly ashes. High carbon fly ashes are becoming more common as by-products of low-NOx combustion technology, and there is need to learn more about this fraction of the fly ash. The project team consists of two universities, Brown and Princeton, and an electrical utility, New England Power. A sample suite of over forty fly ashes has been gathered from utilities across the United States, and includes ashes from a coals ranging in rank from bituminous to lignite. The characterizations of these ashes include standard tests (LOI, Foam Index), as well as more detailed characterizations of their surface areas, porosity, extractability and adsorption behavior. The ultimate goal is, by better characterizing the material, to enable broadening the range of applications for coal fly ash re-use beyond the current main market as a pozzolanic agent for concretes. The potential for high carbon-content fly ashes to substitute for activated carbons is receiving particular attention. The work performed to date has already revealed how very different the surfaces of different ashes produced by the same utility can be, with respect to polarity of the residual carbon. This can help explain the large variations in acceptability of these ashes as concrete additives.

  18. FUNDAMENTAL STUDY OF LOW-NOx COMBUSTION FLY ASH UTILIZATION

    SciTech Connect

    ERIC M. SUUBERG; ROBERT H. HURT

    1998-10-19

    This study is principally concerned with characterizing the organic part of coal combustion fly ashes. High carbon fly ashes are becoming more common as by-products of low-NOx combustion technology, and there is need to learn more about this fraction of the fly ash. The project team consists of two universities, Brown and Princeton, and an electrical utility, New England Power. A sample suite of over fifty fly ashes has been gathered from utilities across the United States, and includes ashes from a coals ranging in rank from bituminous to lignite. The characterizations of these ashes include standard tests (LOI, Foam Index), as well as more detailed characterizations of their surface areas, porosity, extractability and adsorption behavior. The ultimate goal is, by better characterizing the material, to enable broadening the range of applications for coal fly ash re-use beyond the current main market as a pozzolanic agent for concretes. The potential for high carbon-content fly ashes to substitute for activated carbons is receiving particular attention. The work performed to date has already revealed how very different the surfaces of different ashes produced by the same utility can be, with respect to polarity of the residual carbon. This can help explain the large variations in acceptability of these ashes as concrete additives.

  19. Fundamental Study of Low NOx Combustion Fly Ash Utilization

    SciTech Connect

    E. M. Suubert; I. Kuloats; K. Smith; N. Sabanegh; R.H. Hurt; W. D. Lilly; Y. M. Gao

    1997-05-01

    This study is principally concerned with characterizing the organic part of coal combustion fly ashes. High carbon fly ashes are becoming more common as by-products of low-NOx combustion technology, and there is need to learn more about this fraction of the fly ash. The project team consists of two universities, Brown and Princeton, and an electrical utility, New England Power. A sample suite of over forty fly ashes has been gathered from utilities across the United States, and includes ashes from a coals ranging in rank from bituminous to lignite. The characterizations of these ashes include standard tests (LOI, Foam Index), as well as more detailed characterizations of their surface areas, porosity, extractability and adsorption behavior. The ultimate goal is, by better characterizing the material, to enable broadening the range of applications for coal fly ash re-use beyond the current main market as a pozzolanic agent for concretes. The potential for high carbon-content fly ashes to substitute for activated carbons is receiving particular attention. The work performed to date has already revealed how very different the surfaces of different ashes produced by the same utility can be, with respect to polarity of the residual carbon. This can help explain the large variations in acceptability of these ashes as concrete additives.

  20. Study of optical sound generation and amplification

    NASA Astrophysics Data System (ADS)

    Bass, Henry E.; Shields, F. D.

    1986-11-01

    This project involves three separate tasks, i.e.: (1) generation of low frequency sound from optical pulses; (2) propagation of sound through a gas with an overpopulation of vibrationally excited states; and, (3) optoacoustic studies in liquids. The three tasks, funded by the physics division of ONR, represent a three-pronged study of the generation of sound by the absorption of light and amplification of a propagating sound wave. Generation of low frequency sound from a series of optical pulses involves optimizing the density of pulses to obtain maximum energy at low frequencies. The present effort is devoted to numerical simulation. With present modulation schemes, as much as 50% of the energy appears in the desired fundamental, but predicted harmonic distortion is unacceptable. Amplification of sound propagating through gas with an overpopulation of vibrationally excited states has now been observed in N2/H2,N2/He, and N2/CH4 mixtures. The gas is excited with an electrical discharge. Present efforts are devoted to achieving better agreement between theory and experiment. Optoacoustic pulses have been observed in several alcohols and water. The optoacoustic amplitude has been observed as a function of laser energy, distance from excitation zone to detection region, and optical absorption coefficient.

  1. Utility of optical coherence tomography in the evaluation of monocular visual loss related to retinal ischemia.

    PubMed

    Nolan, Rachel; Narayana, Kannan; Beh, Shin C; Rucker, Janet C; Balcer, Laura J; Galetta, Steven L

    2016-04-01

    We report four patients with monocular visual loss for whom optical coherence tomography (OCT) was helpful in distinguishing the sequelae of retinal artery occlusion from those of primary optic neuropathy. Determinations of the peripapillary retinal nerve fiber layer (RNFL) thickness as well as macular retinal layer thicknesses and architecture were used. The major findings in our patients show that changes in the inner retinal layers (including ganglion cell and inner plexiform layer) with disruption of normal macular architecture supports a diagnosis of retinal artery occlusion. Our results support the use of OCT imaging for patients with monocular visual loss of uncertain etiology; macular imaging as well as peripapillary RNFL thickness measurement can be helpful in differentiating primary retinal disease or ischemia from primary disorders of the optic nerve.

  2. Utilization of solar radiation by polar animals: an optical model for pelts.

    PubMed

    Grojean, R E; Sousa, J A; Henry, M C

    1980-02-01

    A summary of existing passive solar-heat conversion panels provides the basis for a definition of an ideal passive solar-heat converter. Evidence for the existence of a biological greenhouse effect in certain homopolar homeothermic species is reviewed. The thermal and optical properties of homeothermic pelts, in particular those of the polar bear, are described, and a qualitative optical model of the polar bear pelt is proposed. The effectiveness of polar bear and seal pelts as solar-heat converters is discussed, and comparison is made with the ideal converter.

  3. Utilization of solar radiation by polar animals: an optical model for pelts

    SciTech Connect

    Grojean, R.E.; Sousa, J.A.; Henry, M.C.

    1980-02-01

    A summary of existing passive solar-heat conversion panels provides the basis for a definition of an ideal passive solar-heat converter. Evidence for the existence of a biological greenhouse effect in certain homopolar homeothermic species is reviewed. The thermal and optical properties of homeothermic pelts, in particular those of the polar bear, are described, and a qualitative optical model of the polar bear pelt is proposed. The effectiveness of polar bear and seal pelts as solar-heat converters is discussed, and comparison is made with the ideal converter.

  4. Six-dimensional optical storage utilizing wavelength selective, polarization sensitive, and reflectivity graded Bragg reflectors

    NASA Astrophysics Data System (ADS)

    Liu, Shangqing

    2014-09-01

    An optical storage system which stores data in three spacial and three physical dimensions is designed and investigated. Its feasibility has been demonstrated by theoretical derivation and numerical calculation. This system has comprehensive advantages including very large capacity, ultrafast throughputs, relatively simple structure and compatibility with CD and DVD. It's an actually practicable technology. With two-photon absorption writing/erasing and optical coherence tomography reading, its storage capacity is over 32 Tbytes per DVD sized disk, and its reading speed is over 25 Gbits/s with high signal-to-noise ratio of over 76 dB. The larger capacity of over 1 Pbyte per disk is potential.

  5. Study of fiber optic sugar sensor

    NASA Astrophysics Data System (ADS)

    Jayanth Kumar, A.; Gowri, N. M.; Venkateswara Raju, R.; Nirmala, G.; Bellubbi, B. S.; Radha Krishna, T.

    2006-08-01

    Over the last two decades, the fiber optic technology has passed through many analytical stages. Some commercially available fiber optic sensors, though in a small way, are being used for automation in mechanical and industrial environments. They are also used for instrumentation and controls. In the present work, an intensity-modulated intrinsic fiber optic sugar sensor is presented. This type of sensor, with slight modification, can be used for on-line determination of the concentration of sugar content in sugarcane juice in sugar industry. In the present set-up, a plastic fiber made of polymethylmethacrylate is used. A portion of the cladding (1 cm, 2 cm, 3 cm) at the mid-point along the length of the fiber is removed. This portion is immersed in sugar solution of known concentration and refractive index. At one end of the fiber an 850 nm source is used and at the other end a power meter is connected. By varying the concentration of sugar solution, the output power is noted. These studies are made due to the change in refractive index of the fluid. The device was found to be very sensitive which is free from EMI and shock hazards, stable and repeatable and they can be remotely interfaced with a computer to give on-line measurements and thus become useful for application in sugar industries.

  6. Shuttle sortie electro-optical instruments study

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A study to determine the feasibility of adapting existing electro-optical instruments (designed and sucessfully used for ground operations) for use on a shuttle sortie flight and to perform satisfactorily in the space environment is considered. The suitability of these two instruments (a custom made image intensifier camera system and an off-the-shelf secondary electron conduction television camera) to support a barium ion cloud experiment was studied for two different modes of spacelab operation - within the pressurized module and on the pallet.

  7. Fibre optic sensors for heat transfer studies

    NASA Astrophysics Data System (ADS)

    Sinha, Pranay G.

    This thesis describes the design and development of a prototype sensor, based on a miniature optical fiber Fabry-Perot interferometer, for heat transfer studies on model turbomachinery components in transient flow wind tunnels. These sensors overcome a number of difficulties which are often encountered in using conventional electrical thin-film resistance gauges such as in the measurement of rapidly varying heat transfer rates, spatial resolution, electromagnetic interference, calibration and signal processing. The special features of the optical sensor are: (1) short length (less than 5 mm), and therefore embeddable in thin structures of model components; (2) direct measurement of heat flux rates; (3) calorimetric operation with temperature resolution of less than 25 mK over a measurement bandwidth of 100 kHz; (4) capability of measuring heat flux less than 5 kWm(exp -2) with measurement range in excess of 10 MWm(exp -2); (5) temporal response time of less than 10 microseconds; (6) minimal thermal disturbances because models are often made of ceramic materials with thermal properties similar to those of the optical fiber from which sensors are made;(7) possibility of using in models with dissimilar thermal properties to the optical fiber, for example, metals; (8) spatial resolution of less than 5 microns; (9) remote operation; (10) an ability to be multiplexed; and (11) immunity to electromagnetic interference. A detailed discussion of the design considerations for the sensor, system development, evaluation of the sensor performance both in the laboratory and wind tunnel environments is presented in this thesis. The performance of the sensor compared favorably with electrical gauges namely, platinum thin-film resistance thermometers. A 4-sensor multiplexed system has been successfully operated, and is reported in the thesis. A brief discussion is also included to indicate that the same sensor design may be considered for applications in other engineering areas.

  8. Fibre Optic Sensors for Heat Transfer Studies.

    NASA Astrophysics Data System (ADS)

    Sinha, Pranay G.

    Available from UMI in association with The British Library. This thesis describes the design and development of a prototype sensor, based on a miniature optical fibre Fabry-Perot interferometer, for heat transfer studies on model turbomachinery components in transient flow wind tunnels. These sensors overcome a number of difficulties which are often encountered in using conventional electrical thin-film resistance gauges such as in the measurement of rapidly varying heat transfer rates, spatial resolution, electromagnetic interference, calibration and signal processing. The special features of the optical sensor are: (i) short length (<5 mm), and therefore embeddable in thin structures of model components; (ii) direct measurement of heat flux rates; (iii) calorimetric operation with temperature resolution of <25 mK over a measurement bandwidth of 100 kHz: (iv) capability of measuring heat flux <5 kWm^ {-2} with measurement range in excess of 10 MWm^{-2}; (v) temporal response time of <10 mus; (vi) minimal thermal disturbances because models are often made of ceramic materials with thermal properties similar to those of the optical fibre from which sensors are made; (vii) possibility of using in models with dissimilar thermal properties to the optical fibre, for example, metals; (viii) spatial resolution of <5 mu m; (ix) remote operation; (x) an ability to be multiplexed; and (xi) immunity to electromagnetic interference. A detailed discussion of the design considerations for the sensor, system development, evaluation of the sensor performance both in the laboratory and wind tunnel environments is presented in this thesis. The performance of the sensor compared favourably with electrical gauges namely, platinum thin-film resistance thermometers. A 4-sensor multiplexed system has been sucessfully operated, and is reported in the thesis. A brief discussion is also included to indicate that the same sensor design may be considered for applications in other engineering

  9. Feasibility study on utilization of vitrified wastes as radiation sources

    NASA Astrophysics Data System (ADS)

    Makuuchi, K.; Yoshii, F.; Hyakutake, K.

    1995-02-01

    A feasibility study on utilization of vitrified high level waste as radiation source has been carried out. Natural rubber latex was radiation vulcanized with VW to demonstrate the feasibility. The dose rate was 0.1 kGy/hr. As a sensitizer, n-butyl acrylate was added. Negligible small activation of NR latex by neutron from the waste was observed. The residual sensitizer in the irradiated latex and physical properties of film molded from the irradiated latex were the same level with the conventional RVNRL with gamma-rays from Co-60. These results suggested that vitrified high level waste can be used as an industrial radiation source.

  10. Development of the water window imaging X-ray microscope utilizing normal-incidence multilayer optics

    NASA Technical Reports Server (NTRS)

    Hoover, Richard B.; Shealy, David L.; Brinkley, B. R.; Baker, Phillip C.; Barbee, Troy W., Jr.; Walker, Arthur B. C., Jr.

    1991-01-01

    A water-window imaging X-ray telescope configured with normal-incidence multilayer X-ray mirrors has been developed to obtain images with unprecedented spatial resolution and contrast of carbon-based microstructures within living cells. The narrow bandpass response inherent in multilayer X-ray optics is accurately tuned to wavelengths within the water window.

  11. Development of the water window imaging X-ray microscope utilizing normal-incidence multilayer optics

    NASA Technical Reports Server (NTRS)

    Hoover, Richard B.; Shealy, David L.; Brinkley, B. R.; Baker, Phillip C.; Barbee, Troy W., Jr.; Walker, Arthur B. C., Jr.

    1991-01-01

    A water-window imaging X-ray telescope configured with normal-incidence multilayer X-ray mirrors has been developed to obtain images with unprecedented spatial resolution and contrast of carbon-based microstructures within living cells. The narrow bandpass response inherent in multilayer X-ray optics is accurately tuned to wavelengths within the water window.

  12. MultiGbit/s optical LAN utilizing a passive WDM star: toward an experimental prototype

    NASA Astrophysics Data System (ADS)

    Barry, Charles F.; Hickey, Michael J.; Noronha, Ciro A., Jr.; Taranenko, Nina L.; Kazovsky, Leonid G.

    1993-11-01

    STARNET is an optical broadband local area network based on a physical passive star topology intended for backbone applications. Over a single physical network, STARNET offers all users both a moderate-speed packet switched subnetwork and a reconfigurable high- speed (up to 2.5 Gbps) Wavelength Division Multiplexed (WDM) circuit switched subnetwork. Based on these two data transport facilities, several topological and protocol solutions are available to the users. As a result, STARNET supports traffic of widely different speed and continuity characteristics. This paper describes an ongoing experimental effort aimed at the realization of a STARNET prototype network at the Optical Communication Research Laboratory of Stanford University. The prototype nodes are FDDI data rate and format compatible in the packet switched subnetwork and currently use 8B/10B encoded data at a rate of 1.25 Gbps in the circuit switched subnetwork. The STARNET network serves high performance workstations running distributed multimedia applications, including video- conferencing. In this paper, the electronic hardware which interfaces the workstation to the STARNET optics is described. The moderate-speed interface uses an off-the-shelf FDDI-on- copper module to interface to the STARNET optics; a custom high-speed interface module provides fast packet switching (electronic) over the circuit switched (wavelength) subnetwork.

  13. Optics-Based Quantum Information and Sensing Platforms Utilizing the Nitrogen-Vacancy Center in Diamond

    NASA Astrophysics Data System (ADS)

    Gould, Michael

    The nitrogen-vacancy (NV) center is a point defect in the diamond crystal lattice, forming a localized-electron system with unique optical and spin properties. In particular, optical control and read-out of the spin state, combined with long spin coherence times, make it an attractive candidate for both high-sensitivity magnetometry and as a solid-state spin qubit for quantum information processing (QIP). This dissertation documents the design, implementation, and characterization of systems aimed at each of these applications. First, the development of a GaP-on-diamond integrated photonics platform for QIP is presented. This work is motivated in part by the scalability advantages that are inherent to photonic device integration, and more fundamentally by the large potential improvements in performance. Specifically, coupling NV centers to integrated optical resonators should enable orders of magnitude improvement in entanglement generation rate through improved photon collection efficiency. This will be crucial for the development of even small-scale QIP systems, as NV-NV spin entanglement has so far only been demonstrated at rates far below the spin decoherence rate, effectively limiting NV-based QIP to two-qubit systems. Large numbers of integrated optical devices were fabricated, including optical resonators. Passive transmission measurements were performed on hundreds of individual devices, enabling statistical performance metrics and device yields to be extracted for several components. Device-coupled single-photon measurements are also presented, indicating photon collection efficiencies as high as 9%, corresponding to an efficiency-limited entanglement rate far exceeding the best reported spin decoherence rate. These results put the GaP-on-diamond platform in a competitive position relative to other photonic integration efforts for QIP. Next, a magneto-optical microscope for bio-sensing applications is presented. The microscope images photoluminescence

  14. Preliminary Study of Plutonium Utilization in AP1000 Reactor

    NASA Astrophysics Data System (ADS)

    Nailatussaadah; Prastyo, Puguh A.; Waris, Abdul; Kurniadi, Rizal; Pramuditya, Syeilendra

    2017-07-01

    Preliminary study of plutonium utilization in AP1000 reactor has been conducted. This study evaluated the standard of Westinghouse AP1000 reactor and ZrB2 as Integral Fuel Burnable Absorber (IFBA). Different fuel compositions of assembly type were analyze in by using SRAC 2006 code system with JENDL 4.0 nuclear data library. This study aiming to compare the neutronics characteristics of an UO2 and an(U,Pu)O2 assembly designs. Some results of the study show that optimal criticality of the fuel assembly can be accomplished by using 5% enrichment of U-235 for UO2 fuel and 8.75% plutonium fraction for(U,Pu)O2 fuel assembly.

  15. Assembly, Alignment, And Cold Focus Test Methods Utilized On Claes Optics

    NASA Astrophysics Data System (ADS)

    Dawson, Juan C.; Kauer, John F.; Reilly, Charles M.; Steakley, Bruce C.

    1988-04-01

    The CLAES Telescope and Spectrometer were aligned as separate units. The optical interface between the two units is at the intermediate Lyot stop, where close angular and centering tolerances are required, with control by the use of matched machined tooling. In the alignme-L. of the Spectrometer, all optical components were centered to the chief ray using centering targets to align the optical components. The initial assembly was made at room temperature, and tested at 20K. One key reason for this testing is that the refractive indices for ZnS and ZnSe are not known below 90K, and therefore the exact location of the image plane is not known. The tests at 20K established the location of the image plane. A beam of collimated carbon-dioxide laser power illuminates the cryogenically cooled Spectrometer or the CLAES Instrument along the optical axis. The collimation of the beam is adjustable in small increments; the beam is scanned over the edges of the individual detectors creating edge scans that were used to determine where the image plane is located. Given the offset from exact collimation of the input beam, the corrections required to locate the image at the detector plane are computed. To determine "best focus", the inverse of the slopes of the edge-traces are plotted. Data obtained on both sides of best focus is plotted; the curves look like parabolas with upward arms. The minimum of this curve is defined as the location of the image plane. Shims that compensate for the focus errors are cut to the correct thickness, and installed. In addition to setting focus, the cryogenic tests were used to determine stability of the optics over the specified environment, and blur size measurements were performed at operational temperatures.

  16. Role of UCG in maximizing coal utilization: site specific study

    SciTech Connect

    Linn, J. K.; Love, S. L.

    1980-01-01

    The Department of Energy is sponsoring a project to develop a planning scheme for improving the utilization of coal deposits. This prototype study, called Total Economic Coal Utilization (TECU), is being applied to specific coal reserves within the Centralia-Chehalis District of Washington State. A significant aspect of the study is to determine the potential role for in situ gasification in maximizing the energy recovery and use. The results obtained indicate that UCG could be used to realize a sizeable increase in the amount of energy that can be economically recovered from the District. Since UCG technology has not reached the commercialization stage, some significant assumptions had to be made for this study. These are that the in situ process will work reliably and that product gas cleanup will proceed without major problems. However, if these conditions are met, this assessment indicates that in situ coal gasification could increase the extractable energy from Washington's Centralia-Chehalis coal deposits by a substantial amount and that this additional energy could be accessed at reasonable cost.

  17. Guidelines for Planning in Colleges and Universities. Volume 5: Physical Plant Planning, Utilities Studies.

    ERIC Educational Resources Information Center

    Pinnell, Charles; Wacholder, Michael

    The fifth and final volume of a series concerned with higher educational facilities planning expands the discussion of the utilities planning process initiated in the overview of volume one. Three major classes of utilities--energy utilities, service utilities, and communications utilities are studied. Their influences on the overall physical…

  18. Optical design study for NASA's spherical primary optical telescope (SPOT)

    NASA Astrophysics Data System (ADS)

    Howard, Joseph M.

    2004-10-01

    Several of NASA's future space telescopes project teams have chosen or are considering segmented primary mirrors as a part of their architecture. The James Webb Space Telescope (JWST) design employs a 6.5-meter conic primary mirror constructed of 18 hexagonal segments, where each hex is one of three off-axis surface profiles corresponding to its radial distance to the parent mirror axis. Other future mission concepts such as SAFIR (Single Aperture Far-Infra Red) and SUVO (Space Ultra Violet Optical telescope) are considering even larger segmented primary mirrors. The goal of the Spherical Primary Optical Telescope (SPOT) project discussed in this paper is to investigate the option of a spherical primary mirror for such future large aperture NASA missions. Ground-based telescopes such as the Hobby-Eberly have realized this design option, and the current baseline design for ESO's OWL project incorporates a 100-meter segmented spherical primary mirror. While the benefits of fabricating large numbers of identical spherical surface segments are obvious, the optical design for the telescope becomes more complex in order to correct the significant aberration resulting from a spherical primary surface. This paper briefly surveys design approaches of spherical primary telescopes. Image based performance comparisons are made, and examples are presented.

  19. Role of amplified spontaneous emission in optical free-space communication links with optical amplification: impact on isolation and data transmission and utilization for pointing, acquisition, and

    NASA Astrophysics Data System (ADS)

    Winzer, Peter J.; Kalmar, Andras; Leeb, Walter R.

    1999-04-01

    We investigate the role of amplified spontaneous emission (ASE) produced by an optical booster amplifier at the transmitter of free-space optical communication links. In a communication terminal with a single telescope for both transmission and reception, this ASE power has to be taken into account in connection with transmit-to-receive channel isolation, especially since it partly occupies the same state of polarization and the same frequency band as the receive signal. We show that the booster ASE intercepted by the receiver can represent a non-negligible source of background radiation: In a typical optical intersatellite link scenario, the ASE power spectral density generated by the booster amplifier at the transmitter and coupled to the receiver will be on the order of 10-20 W/Hz, which equals the background radiation of the sun. Exploiting these findings for pointing, acquisition, and tracking (PAT) purposes, we describe a patent-pending PAT system doing without beacon lasers and without the need for diverting a part of the data signal for PAT. Utilizing the transmit booster ASE over a bandwidth of e.g. 20 nm at the receiver, a total power of about -46 dBm is available for PAT purposes without extra power consumption at the transmitter and without the need for beacon lAser alignment.

  20. Measurements and properties of ice particles and carbon dioxide bubbles in aqueous mixture utilizing optical techniques

    NASA Astrophysics Data System (ADS)

    Diallo, Amadou O.

    Optical techniques are used to determine the size, shape and many other properties of particles ranging from the micro to a nano-level. These techniques have endless applications. This research is based on a project assigned by a "Vendor" that wants anonymity. The Leica optical microscope and the Dark Field Polarizing Metallurgical Microscope is used to determine the size and count of ice crystals (Vendors products) in multiple time frames. Since the ice temperature influences, its symmetry and the shape is subject to changes at room temperature (300 K) and the atmospheric pressure that is exerted on the ice crystals varies. The ice crystals are in a mixture of water, electrolytes and carbon dioxide with the optical spectroscopy (Qpod2) and Spectra suite, the optical density of the ice crystals is established from the absorbance and transmission measurements. The optical density in this case is also referred to as absorption; it is plotted with respect to a frequency (GHz), wavelength (nm) or Raman shift (1/cm) which shows the light colliding with the ice particles and CO2. Depending on the peaks positions, it is possible to profile the ice crystal sizes using a mean distribution plots. The region of absorbency wavelength expected for the ice is in the visible range; the water molecules in the (UV) Ultra-violet range and the CO2 in the (IR) infrared region. It is also possible to obtain the reflection and transmission output as a percentage change with the wavelengths ranging from 200 to 1100 nm. The refractive index of the ice can be correlated to the density based on the optical acoustic theorem, or Mie Scattering Theory. The viscosity of the ice crystals and the solutions from which the ice crystals are made of as well are recorded with the SV-10 viscometer. The baseline viscosity is used as reference and set lower than that of the ice crystals. The Zeta potential of the particles present in the mixture are approximated by first finding the viscosity of the

  1. Mechanistic and inhibition studies of chorismate-utilizing enzymes.

    PubMed

    Kerbarh, O; Bulloch, E M M; Payne, R J; Sahr, T; Rébeillé, F; Abell, C

    2005-08-01

    The shikimate biosynthetic pathway is utilized in algae, higher plants, bacteria, fungi and apicomplexan parasites; it involves seven enzymatic steps in which phosphoenolpyruvate and erythrose 4-phosphate are converted into chorismate. In Escherichia coli, five chorismate-utilizing enzymes catalyse the synthesis of aromatic compounds such as L-phenylalanine, L-tyrosine, L-tryptophan, folate, ubiquinone and siderophores such as yersiniabactin and enterobactin. As mammals do not possess such a biosynthetic system, the enzymes involved in the pathway have aroused considerable interest as potential targets for the development of antimicrobial drugs and herbicides. As an initiative to investigate the mechanism of some of these enzymes, we showed that the antimicrobial effect of (6S)-6-fluoroshikimate is the result of irreversible inhibition of 4-amino-4-deoxychorismate synthase by 2-fluorochorismate. Based on this study, a catalytic mechanism for this enzyme was proposed, in which the residue Lys-274 is involved in the formation of a covalent intermediate. In another study, Yersinia enterocolitica Irp9, which is involved in the biosynthesis of the siderophore yersiniabactin, was for the first time biochemically characterized and shown to catalyse the formation of salicylate from chorismate via isochorismate as a reaction intermediate. A three-dimensional model for this enzyme was constructed that will guide the search for potent inhibitors of salicylate formation, and hence of bacterial iron uptake.

  2. Evaluation of the uncertainty in an EBT3 film dosimetry system utilizing net optical density.

    PubMed

    Marroquin, Elsa Y León; Herrera González, José A; Camacho López, Miguel A; Barajas, José E Villarreal; García-Garduño, Olivia A

    2016-09-01

    Radiochromic film has become an important tool to verify dose distributions for intensity-modulated radiotherapy (IMRT) and quality assurance (QA) procedures. A new radiochromic film model, EBT3, has recently become available, whose composition and thickness of the sensitive layer are the same as those of previous EBT2 films. However, a matte polyester layer was added to EBT3 to prevent the formation of Newton's rings. Furthermore, the symmetrical design of EBT3 allows the user to eliminate side-orientation dependence. This film and the flatbed scanner, Epson Perfection V750, form a dosimetry system whose intrinsic characteristics were studied in this work. In addition, uncertainties associated with these intrinsic characteristics and the total uncertainty of the dosimetry system were determined. The analysis of the response of the radiochromic film (net optical density) and the fitting of the experimental data to a potential function yielded an uncertainty of 2.6%, 4.3%, and 4.1% for the red, green, and blue channels, respectively. In this work, the dosimetry system presents an uncertainty in resolving the dose of 1.8% for doses greater than 0.8 Gy and less than 6 Gy for red channel. The films irradiated between 0 and 120 Gy show differences in the response when scanned in portrait or landscape mode; less uncertainty was found when using the portrait mode. The response of the film depended on the position on the bed of the scanner, contributing an uncertainty of 2% for the red, 3% for the green, and 4.5% for the blue when placing the film around the center of the bed of scanner. Furthermore, the uniformity and reproducibility radiochromic film and reproducibility of the response of the scanner contribute less than 1% to the overall uncertainty in dose. Finally, the total dose uncertainty was 3.2%, 4.9%, and 5.2% for red, green, and blue channels, respectively. The above uncertainty values were obtained by minimizing the contribution to the total dose uncertainty

  3. Evaluation of the uncertainty in an EBT3 film dosimetry system utilizing net optical density.

    PubMed

    León Marroquin, Elsa Y; Herrera González, José A; Camacho López, Miguel A; Villarreal Barajas, José E; García-Garduño, Olivia A

    2016-09-08

    Radiochromic film has become an important tool to verify dose distributions for intensity-modulated radiotherapy (IMRT) and quality assurance (QA) procedures. A new radiochromic film model, EBT3, has recently become available, whose composition and thickness of the sensitive layer are the same as those of previous EBT2 films. However, a matte polyester layer was added to EBT3 to prevent the formation of Newton's rings. Furthermore, the symmetrical design of EBT3 allows the user to eliminate side-orientation dependence. This film and the flatbed scanner, Epson Perfection V750, form a dosimetry system whose intrinsic characteristics were studied in this work. In addition, uncertainties associated with these intrinsic characteristics and the total uncertainty of the dosimetry system were determined. The analysis of the response of the radiochromic film (net optical density) and the fitting of the experimental data to a potential function yielded an uncertainty of 2.6%, 4.3%, and 4.1% for the red, green, and blue channels, respectively. In this work, the dosimetry system presents an uncertainty in resolving the dose of 1.8% for doses greater than 0.8 Gy and less than 6 Gy for red channel. The films irradiated between 0 and 120 Gy show differences in the response when scanned in portrait or landscape mode; less uncertainty was found when using the portrait mode. The response of the film depended on the position on the bed of the scanner, contributing an uncertainty of 2% for the red, 3% for the green, and 4.5% for the blue when placing the film around the center of the bed of scanner. Furthermore, the uniformity and reproducibility radiochromic film and reproducibility of the response of the scanner contribute less than 1% to the overall uncertainty in dose. Finally, the total dose uncertainty was 3.2%, 4.9%, and 5.2% for red, green, and blue channels, respectively. The above uncertainty values were obtained by mini-mizing the contribution to the total dose uncertainty

  4. Single Mode Optical Waveguide Design Study.

    DTIC Science & Technology

    1981-11-23

    AD-I7g62 CORNING GLASS WORKS NY FIG 20/6 ADA0 21 SINGLE MODE OPTICAL WAVEGUIDE DESIGN STUDY.(U) NOV 81 V A BHAGAVATJLA. D B KECK, R A WESTWIG N00173...Ralph A. Westwig Corning Glass Works ’ 1 / Research and Development-Division Sullivan Park Corning, New York Th document ha bern c -yro vd Spubc rlea...Authors: Venkata A. Bhagavatula Donald B. Keck Ralph A. Westwig Corning Glass Works Research and Development Division Sullivan Park Corning, New York 11

  5. Potential clinical utility of a fibre optic-coupled dosemeter for dose measurements in diagnostic radiology.

    PubMed

    Jones, A Kyle; Hintenlang, David

    2008-01-01

    Many types of dosemeters have been investigated for absorbed dose measurements in diagnostic radiology, including ionisation chambers, metal-oxide semiconductor field-effect transistor dosemeters, thermoluminescent dosemeters, optically stimulated luminescence detectors, film and diodes. Each of the aforementioned dosemeters suffers from a critical limitation, either the need to interrogate, or read, the dosemeter to retrieve dose information or large size to achieve adequate sensitivity. This work presents an evaluation of a fibre optic-coupled dosemeter (FOCD) for use in diagnostic radiology dose measurement. This dosemeter is small, tissue-equivalent and capable of providing true real-time dose information. The FOCD has been evaluated for dose linearity, angular dependence, sensitivity and energy dependence at energies, beam qualities and beam quantities relevant to diagnostic radiology. The FOCD displayed excellent dose linearity and high sensitivity, while exhibiting minimal angular dependence of response. However, the dosemeter does exhibit positive energy dependence, and is subject to attenuation of response when bent.

  6. Flexible optical clock recovery utilizing a multi-function semiconductor fiber laser

    NASA Astrophysics Data System (ADS)

    Feng, H.; Zhao, W.; Xie, X. P.; Qian, F. C.; Wang, W.; Huang, X.; Hu, H.

    2013-08-01

    We demonstrate a multi-function fiber laser based on cross-gain modulation in a semiconductor optical amplifier (SOA). Depending on the input signals, the fiber cavity can emit a continuous wave (CW) laser, mode-locked pulses, or act as a clock recovery device. With an extra CW light overcoming the pattern effect in the clock recovery process, a 10-GHz synchronous clock sequence with <0.1 power fluctuation and <120-fs timing jitter is extracted from the transmission return-to-zero data stream. We further analyze the recovered clock properties as a function of the input signal, and find that the clock recovery system presents good stability over a large range of input signal characteristics. The multi-function fiber laser exhibits the advantages of compact configuration and low cost, which is very convenient and attractive for optical communications and signal processing.

  7. Real-time optical path control method that utilizes multiple support vector machines for traffic prediction

    NASA Astrophysics Data System (ADS)

    Kawase, Hiroshi; Mori, Yojiro; Hasegawa, Hiroshi; Sato, Ken-ichi

    2016-02-01

    An effective solution to the continuous Internet traffic expansion is to offload traffic to lower layers such as the L2 or L1 optical layers. One possible approach is to introduce dynamic optical path operations such as adaptive establishment/tear down according to traffic variation. Path operations cannot be done instantaneously; hence, traffic prediction is essential. Conventional prediction techniques need optimal parameter values to be determined in advance by averaging long-term variations from the past. However, this does not allow adaptation to the ever-changing short-term variations expected to be common in future networks. In this paper, we propose a real-time optical path control method based on a machinelearning technique involving support vector machines (SVMs). A SVM learns the most recent traffic characteristics, and so enables better adaptation to temporal traffic variations than conventional techniques. The difficulty lies in determining how to minimize the time gap between optical path operation and buffer management at the originating points of those paths. The gap makes the required learning data set enormous and the learning process costly. To resolve the problem, we propose the adoption of multiple SVMs running in parallel, trained with non-overlapping subsets of the original data set. The maximum value of the outputs of these SVMs will be the estimated number of necessary paths. Numerical experiments prove that our proposed method outperforms a conventional prediction method, the autoregressive moving average method with optimal parameter values determined by Akaike's information criterion, and reduces the packet-loss ratio by up to 98%.

  8. Energy-efficient utilization of bipolar optical forces in nano-optomechanical cavities.

    PubMed

    Tian, Feng; Zhou, Guangya; Du, Yu; Chau, Fook Siong; Deng, Jie; Tang, Xiaosong; Akkipeddi, Ramam

    2013-07-29

    Nanoscale all-optical circuits driven by optical forces have broad applications in future communication, computation, and sensing systems. Because human society faces huge challenges of energy saving and emission reduction, it is very important to develop energy-efficient nano-optomechanical devices. Due to their high quality (Q) factors, resonance modes of cavities are capable of generating much larger forces than waveguide modes. Here we experimentally demonstrate the use of resonance modes of double-coupled one-dimensional photonic crystal cavities to generate bipolar optical forces. Attractive and repulsive forces of -6.2 nN and 1.9 nN were obtained with respective launching powers of 0.81 mW and 0.87 mW in the waveguide just before cavities. Supported by flexible nanosprings (spring constant 0.166 N/m), one cavity is pulled to (pushed away from) the other cavity by 37.1 nm (11.4 nm). The shifts of the selected resonance modes of the device are mechanically and thermally calibrated with an integrated nanoelectromechanical system actuator and a temperature-controlled testing platform respectively. Based on these experimentally-obtained relations, probe mode shifts due to the optomechanical effect are decoupled from those due to the thermo-optic effect. Actuated by the third-order even pump mode, the optomechanical shift of the second-order even probe mode is found to be about 2.5 times its thermal shift, indicating a highly efficient conversion of light energy to mechanical energy.

  9. A novel elastic optical path network that utilizes bitrate-specific anchored frequency slot arrangement.

    PubMed

    Shen, Zhi-shu; Hasegawa, Hiroshi; Sato, Ken-ichi; Tanaka, Takafumi; Hirano, Akira

    2014-02-10

    We propose a novel elastic optical path network where each specific bitrate signal uses its own dedicated fixed grid and one edge of its frequency grid is anchored at a specific frequency. Numerical evaluations using various bitrate signal patterns and network topologies show that the network proposal can almost match the performance of conventional flexible grid networks, while greatly mitigating the hardware requirements: it allows the use of the tunable filters for the fixed grid systems.

  10. Optical phase modulator utilizing a transparent piezofilm for use with the extrinsic fiber interferometer

    NASA Astrophysics Data System (ADS)

    Sudarshanam, V. S.; Claus, Richard O.

    1993-03-01

    A piezoelectnc polyvinylidene flouride (PVF2) film with transparent indium tin oxide electrode metallization is placed directly in the path of a single mode fiber output, to form an extrinsic optical interferometer. This device can be used concurrently with another extrinsic inteferometer on a fiber directional coupler to generate a carrier phase modulation on which the signal phase shift is superimposed. Experimental results of the induced phase shifting coefficient are presented for two arrangements of the piezofilm differing in their boundary clamping conditions.

  11. Enhancing optical absorption in InP and GaAs utilizing profile etching

    NASA Technical Reports Server (NTRS)

    Bailey, Sheila G.; Fatemi, Navid S.; Landis, Geoffrey A.

    1991-01-01

    The current state of profile etching in GaAs and InP is summarized, including data on novel geometries attainable as a function of etchant temperature, composition, and rate; substrate orientation; carrier concentration; and oxide thickness between substrate and photoresist. V-grooved solar cells were manufactured with both GaAs and InP, and the improved optical absorption was demonstrated. Preferred parameters for various applications are listed and discussed.

  12. SAFENET 2 fiber optic implementation study

    NASA Astrophysics Data System (ADS)

    Townsend, V. W.; Sevinsky, T. P.; Owens, F. J.

    1991-06-01

    The SAFENET II draft Military Handbook, MCCR-0036-DRAFT, establishes requirements and provides guidance for the implementation of a Survivable Adaptable Fiber Optic Network. SAFENET II. The fiber optics communications channel essentially adopts the ANSI Fiber Distributed Data Interface (FDDI) Physical Layer Medium Dependent (PMD) Specification, modified by a requirement for increased transmitter optical output power and decreased minimum receiver optical input power (increased sensitivity) to provide a 21 dB overall optical flux budget between (and including) the equipment fiber optic interface connectors (FOIC). A network of cables, optical bypass switches, and spliced fiber joints is described in the Handbook which permit ring operation through up to 5 bypassed nodes while maintaining a minimum 6 dB link optical power margin.

  13. Utilization of Field Enhancement in Plasmonic Waveguides for Subwavelength Light-Guiding, Polarization Handling, Heating, and Optical Sensing

    PubMed Central

    Dai, Daoxin; Wu, Hao; Zhang, Wei

    2015-01-01

    Plasmonic nanostructures have attracted intensive attention for many applications in recent years because of the field enhancement at the metal/dielectric interface. First, this strong field enhancement makes it possible to break the diffraction limit and enable subwavelength optical waveguiding, which is desired for nanophotonic integrated circuits with ultra-high integration density. Second, the field enhancement in plasmonic nanostructures occurs only for the polarization mode whose electric field is perpendicular to the metal/dielectric interface, and thus the strong birefringence is beneficial for realizing ultra-small polarization-sensitive/selective devices, including polarization beam splitters, and polarizers. Third, plasmonic nanostructures provide an excellent platform of merging electronics and photonics for some applications, e.g., thermal tuning, photo-thermal detection, etc. Finally, the field enhancement at the metal/dielectric interface helps a lot to realize optical sensors with high sensitivity when introducing plasmonic nanostrutures. In this paper, we give a review for recent progresses on the utilization of field enhancement in plasmonic nanostructures for these applications, e.g., waveguiding, polarization handling, heating, as well as optical sensing. PMID:28793600

  14. RS-34 Phoenix (Peacekeeper Post Boost Propulsion System) Utilization Study

    NASA Technical Reports Server (NTRS)

    Esther, Elizabeth A.; Kos, Larry; Burnside, Christopher G.; Bruno, Cy

    2013-01-01

    The Advanced Concepts Office (ACO) at the NASA Marshall Space Flight Center (MSFC) in conjunction with Pratt & Whitney Rocketdyne conducted a study to evaluate potential in-space applications for the Rocketdyne produced RS-34 propulsion system. The existing RS-34 propulsion system is a remaining asset from the de-commissioned United States Air Force Peacekeeper ICBM program, specifically the pressure-fed storable bipropellant Stage IV Post Boost Propulsion System, renamed Phoenix. MSFC gained experience with the RS-34 propulsion system on the successful Ares I-X flight test program flown in October 2009. RS-34 propulsion system components were harvested from stages supplied by the USAF and used on the Ares I-X Roll control system (RoCS). The heritage hardware proved extremely robust and reliable and sparked interest for further utilization on other potential in-space applications. MSFC is working closely with the USAF to obtain RS-34 stages for re-use opportunities. Prior to pursuit of securing the hardware, MSFC commissioned the Advanced Concepts Office to understand the capability and potential applications for the RS-34 Phoenix stage as it benefits NASA, DoD, and commercial industry. As originally designed, the RS-34 Phoenix provided in-space six-degrees-of freedom operational maneuvering to deploy multiple payloads at various orbital locations. The RS-34 Phoenix Utilization Study sought to understand how the unique capabilities of the RS-34 Phoenix and its application to six candidate missions: 1) small satellite delivery (SSD), 2) orbital debris removal (ODR), 3) ISS re-supply, 4) SLS kick stage, 5) manned GEO servicing precursor mission, and an Earth-Moon L-2 Waypoint mission. The small satellite delivery and orbital debris removal missions were found to closely mimic the heritage RS-34 mission. It is believed that this technology will enable a small, low-cost multiple satellite delivery to multiple orbital locations with a single boost. For both the small

  15. RS-34 Phoenix (Peacekeeper Post Boost Propulsion System) Utilization Study

    NASA Technical Reports Server (NTRS)

    Esther, Elizabeth A.; Kos, Larry; Bruno, Cy

    2012-01-01

    The Advanced Concepts Office (ACO) at the NASA Marshall Space Flight Center (MSFC) in conjunction with Pratt & Whitney Rocketdyne conducted a study to evaluate potential in-space applications for the Rocketdyne produced RS-34 propulsion system. The existing RS-34 propulsion system is a remaining asset from the decommissioned United States Air Force Peacekeeper ICBM program; specifically the pressure-fed storable bipropellant Stage IV Post Boost Propulsion System, renamed Phoenix. MSFC gained experience with the RS-34 propulsion system on the successful Ares I-X flight test program flown in October 2009. RS-34 propulsion system components were harvested from stages supplied by the USAF and used on the Ares I-X Roll control system (RoCS). The heritage hardware proved extremely robust and reliable and sparked interest for further utilization on other potential in-space applications. Subsequently, MSFC is working closely with the USAF to obtain all the remaining RS-34 stages for re-use opportunities. Prior to pursuit of securing the hardware, MSFC commissioned the Advanced Concepts Office to understand the capability and potential applications for the RS-34 Phoenix stage as it benefits NASA, DoD, and commercial industry. Originally designed, the RS-34 Phoenix provided in-space six-degrees-of freedom operational maneuvering to deploy multiple payloads at various orbital locations. The RS-34 Phoenix Utilization Study sought to understand how the unique capabilities of the RS-34 Phoenix and its application to six candidate missions: 1) small satellite delivery (SSD), 2) orbital debris removal (ODR), 3) ISS re-supply, 4) SLS kick stage, 5) manned GEO servicing precursor mission, and an Earth-Moon L-2 Waypoint mission. The small satellite delivery and orbital debris removal missions were found to closely mimic the heritage RS-34 mission. It is believed that this technology will enable a small, low-cost multiple satellite delivery to multiple orbital locations with a single

  16. An Optical Study of Ice Grain Boundaries

    NASA Astrophysics Data System (ADS)

    Thomson, Erik S.

    The equilibrium phase geometry and evolution of polycrystals underlies the nature of materials. In particular, grain boundaries dominate the total interfacial area within polycrystalline materials. Our experimental studies are motivated by the importance of the structure, evolution, and thermodynamic behavior of grain boundaries near bulk melting temperatures. Ice is singled out as a material of interest due to its geophysical importance and its advantageous optical properties. An experimental apparatus and light reflection technique is designed to measure grain boundary melting in ice bicrystals, in thermodynamic equilibrium The technique allows continuous monitoring of reflected light intensity from the grain boundary as the temperature and solutal composition are systematically varied. For each sample the individual crystal orientations are also measured. The type and concentration of impurity in the liquid is controlled and the temperature is continuously recorded and controlled over a range near the melting point. An optical model of the interface is developed in order to convert experimental reflection data into a physical measurement of the liquidity of the grain boundary. Solutions are found for reflection and transmission amplitude coefficients for waves propagating from an arbitrarily oriented uniaxial anisotropic material into an isotropic material. This general model is used to determine solutions for three layer, ice/water/ice, systems with crystals of arbitrary orientation, and is broadly applicable to layered materials. Experimental results show thicker grain boundary liquid layers than expected from classical colligative effects. A physically realistic model of intermolecular interactions succeeds in bounding the measurements. These measurements may have important implications for understanding a wide range of effects in polycrystalline materials. Likewise, the experimental techniques and optical theory may be applied to other systems of broad

  17. Optical tweezers for studying taxis in parasites

    NASA Astrophysics Data System (ADS)

    de Thomaz, A. A.; Fontes, A.; Stahl, C. V.; Pozzo, L. Y.; Ayres, D. C.; Almeida, D. B.; Farias, P. M. A.; Santos, B. S.; Santos-Mallet, J.; Gomes, S. A. O.; Giorgio, S.; Feder, D.; Cesar, C. L.

    2011-04-01

    In this work we present a methodology to measure force strengths and directions of living parasites with an optical tweezers setup. These measurements were used to study the parasites chemotaxis in real time. We observed behavior and measured the force of: (i) Leishmania amazonensis in the presence of two glucose gradients; (ii) Trypanosoma cruzi in the vicinity of the digestive system walls, and (iii) Trypanosoma rangeli in the vicinity of salivary glands as a function of distance. Our results clearly show a chemotactic behavior in every case. This methodology can be used to study any type of taxis, such as chemotaxis, osmotaxis, thermotaxis, phototaxis, of any kind of living microorganisms. These studies can help us to understand the microorganism sensory systems and their response function to these gradients.

  18. Multifunctional nanoprobe to enhance the utility of optical based imaging techniques

    PubMed Central

    Jung, Yeongri; Guan, Guangying; Wei, Chen-wei; Reif, Roberto; Gao, Xiaohu; O’Donnell, Matthew

    2012-01-01

    Abstract. Several imaging modalities such as optical coherence tomography, photothermal, photoacoustic and magnetic resonance imaging, are sensitive to different physical properties (i.e. scattering, absorption and magnetic) that can provide contrast within biological tissues. Usually exogenous agents are designed with specific properties to provide contrast for these imaging methods. In nano-biotechnology there is a need to combine several of these properties into a single contrast agent. This multifunctional contrast agent can then be used by various imaging techniques simultaneously or can be used to develop new imaging modalities. We reported and characterized a multifunctional nanoparticle, made from gold nanoshells, which exhibits scattering, photothermal, photoacoustic, and magnetic properties. PMID:22352665

  19. Utilizing the N beam position monitor method for turn-by-turn optics measurements

    NASA Astrophysics Data System (ADS)

    Langner, A.; Benedetti, G.; Carlà, M.; Iriso, U.; Martí, Z.; de Portugal, J. Coello; Tomás, R.

    2016-09-01

    The N beam position monitor method (N -BPM) which was recently developed for the LHC has significantly improved the precision of optics measurements that are based on BPM turn-by-turn data. The main improvement is due to the consideration of correlations for statistical and systematic error sources, as well as increasing the amount of BPM combinations which are used to derive the β -function at one location. We present how this technique can be applied at light sources like ALBA, and compare the results with other methods.

  20. A spectrally tunable microstructured optical fibre Bragg grating utilizing an infiltrated ferrofluid.

    PubMed

    Candiani, A; Konstantaki, M; Margulis, W; Pissadakis, S

    2010-11-22

    The spectral response of a Bragg grating reflector inscribed in a microstructured optical fibre is tuned by employing an infiltrated ferrofluid, while modifying the overlap of the ferrofluidic medium with the grating length. Significant spectral changes in terms of Bragg grating wavelength shift and extinction ratio were obtained under static magnetic field actuation. Spectral measurements revealed non-bidirectional propagation effects dependent upon the relative position between the ferrofluid and the grating. The actuation speed of the device was measured to be of the order of few seconds.

  1. Clinical utility of anterior segment swept-source optical coherence tomography in glaucoma

    PubMed Central

    Angmo, Dewang; Nongpiur, Monisha E.; Sharma, Reetika; Sidhu, Talvir; Sihota, Ramanjit; Dada, Tanuj

    2016-01-01

    Optical coherence tomography (OCT), a noninvasive imaging modality that uses low-coherence light to obtain a high-resolution cross-section of biological structures, has evolved dramatically over the years. The Swept-source OCT (SS-OCT) makes use of a single detector with a rapidly tunable laser as a light source. The Casia SS-1000 OCT is a Fourier-domain, SS-OCT designed specifically for imaging the anterior segment. This system achieves high resolution imaging of 10΅m (Axial) and 30΅m (Transverse) and high speed scanning of 30,000 A-scans per second. With a substantial improvement in scan speed, the anterior chamber angles can be imaged 360 degrees in 128 cross sections (each with 512 A-scans) in about 2.4 seconds. We summarize the clinical applications of anterior segment SS-OCT in Glaucoma. Literature search: We searched PubMed and included Medline using the phrases anterior segment optical coherence tomography in ophthalmology, swept-source OCT, use of AS-OCT in glaucoma, use of swept-source AS-OCT in glaucoma, quantitative assessment of angle, filtering bleb in AS-OCT, comparison of AS-OCT with gonioscopy and comparison of AS-OCT with UBM. Search was made for articles dating 1990 to August 2015. PMID:27013821

  2. Study of bacterial motility using optical tweezers

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Suddhashil

    Bacteria are arguably the simplest of known microorganisms, forming a fundamental part of the world we live in. Many functions they perform are found in scaled-up versions in higher organisms. Among many advanced functions, bacteria possess the ability to move in search for nutrients and favorable growth conditions. Measurement of the dynamical variables associated with bacterial swimming has proven to be difficult due to the lack of an accurate and convenient tool. In the past optical traps have been used for the manipulation of microscopic objects and measurement of minute forces. Herein, I have devised techniques for use of optical traps for direct measurement of the dynamics of bacterial swimming and chemotaxis, shedding light on the propulsion apparatus and sensory systems. A detailed analysis is performed to explore the effects of non-local hydrodynamic interactions on the swimming of single cells. Due to the lack of reliable measurement techniques, experimentalists often use theoretical models to estimate bacterial dynamics, the validity of which are tested. I emphasize the shortcomings of the very popular Resistive Force Theory (RFT) and indicate how the more rigorous Slender Body Theory (SBT) is able to overcome the limitations. In addition the chemotaxis of the marine bacterial strain Vibrio alginolyticus is studied with the revelation of a previously unknown chemotactic mechanism. Direct observations showed that these cells are able to bend their flagella to impart direction changes, which is paramount for an effective search strategy. This interesting find opens several intriguing questions pertaining to chemotaxis.

  3. Studies of Optical Matrix Multiplication and Reconfigurable Optical Interconnect Concepts

    DTIC Science & Technology

    1989-07-01

    at the uttization, of noil incir optica ! P 1 0 (rl ,1 a p~ ol, 1i 0-5-7 TH VTg2,5 an 0j-,d C m xn 5-7 r~onl~na rn S,9 to pertorni tMe fnc trix...conjugator in conjunction rith a 4S . 48 magneto -optic spatial light modulator (SIGHT-MOD SMD4SI from Semetex Corp.), we have denonstrated the basic principle...and Applications Topical Nleetint Jlune 15-1T. 1988 ’-ouih l aL", -a~le. Ne,,ada Optica ! Se, _,of America Laser> and Elec~ro-Optcs Societ\\ of t

  4. Studies on Optical and Electrical Properties of Hafnium Oxide Nanoparticles

    NASA Astrophysics Data System (ADS)

    Jayaraman, Venkatachalam; Sagadevan, Suresh; Sudhakar, Rajesh

    2017-03-01

    In this paper, the synthesis and physico-chemical properties of hafnium oxide nanoparticles (HfO2 NPs) are analyzed and reported. The synthesis was carried out by the precipitation route by using hafnium tetrachloride (HfCl4) as precursor material with potassium hydroxide (KOH) dissolved in Millipore water. In the precipitation technique, the chemical reaction is comparatively simple, low-cost and non-toxic compared to other synthetic methods. The synthesized HfO2 NPs were characterized by using powder x-ray diffraction (PXRD), ultraviolet-visible (UV-Vis) spectroscopy, Raman analysis, and high-resolution transmission electron microscopy (HRTEM). The monoclinic structure of the HfO2 NPs was resolved utilizing x-ray diffraction (XRD). The optical properties were studied from the UV-Vis absorption spectrum. The optical band gap of the HfO2NPs was observed to be 5.1 eV. The Raman spectrum shows the presence of HfO2 NPs. The HRTEM image showed that the HfO2 NPs were of spherical shape with an average particle size of around 28 nm. The energy-dispersive x-ray spectroscopy (EDS) spectrum obviously demonstrated the presence of HfO2 NPs. Analysis and studies on the dielectric properties of the HfO2 NPs such as the dielectric constant, the dielectric loss, and alternating current (AC) conductivity were carried out at varying frequencies and temperatures.

  5. Studies on Optical and Electrical Properties of Hafnium Oxide Nanoparticles

    NASA Astrophysics Data System (ADS)

    Jayaraman, Venkatachalam; Sagadevan, Suresh; Sudhakar, Rajesh

    2017-07-01

    In this paper, the synthesis and physico-chemical properties of hafnium oxide nanoparticles (HfO2 NPs) are analyzed and reported. The synthesis was carried out by the precipitation route by using hafnium tetrachloride (HfCl4) as precursor material with potassium hydroxide (KOH) dissolved in Millipore water. In the precipitation technique, the chemical reaction is comparatively simple, low-cost and non-toxic compared to other synthetic methods. The synthesized HfO2 NPs were characterized by using powder x-ray diffraction (PXRD), ultraviolet-visible (UV-Vis) spectroscopy, Raman analysis, and high-resolution transmission electron microscopy (HRTEM). The monoclinic structure of the HfO2 NPs was resolved utilizing x-ray diffraction (XRD). The optical properties were studied from the UV-Vis absorption spectrum. The optical band gap of the HfO2NPs was observed to be 5.1 eV. The Raman spectrum shows the presence of HfO2 NPs. The HRTEM image showed that the HfO2 NPs were of spherical shape with an average particle size of around 28 nm. The energy-dispersive x-ray spectroscopy (EDS) spectrum obviously demonstrated the presence of HfO2 NPs. Analysis and studies on the dielectric properties of the HfO2 NPs such as the dielectric constant, the dielectric loss, and alternating current (AC) conductivity were carried out at varying frequencies and temperatures.

  6. FEASIBILITY OF MATCHING STUDY PARTICIPANT RESIDENCE WITH SPECIFIC WATER UTILITY TRIHALOMETHANE (THM) DATA IN EPIDEMIOLOGIC STUDIES

    EPA Science Inventory

    Many epidemiologic studies concerning by-products of water disinfection use utility monitoring data to estimate exposure. Use of such data requires linkage of residence location to a specific water utility and associated monitoring data during a given exposure period. The inabil...

  7. FEASIBILITY OF MATCHING STUDY PARTICIPANT RESIDENCE WITH SPECIFIC WATER UTILITY TRIHALOMETHANE (THM) DATA IN EPIDEMIOLOGIC STUDIES

    EPA Science Inventory

    Many epidemiologic studies concerning by-products of water disinfection use utility monitoring data to estimate exposure. Use of such data requires linkage of residence location to a specific water utility and associated monitoring data during a given exposure period. The inabil...

  8. Diode lasers for direct application by utilizing a trepanning optic for remote oscillation welding of aluminum and copper

    NASA Astrophysics Data System (ADS)

    Fritsche, Haro; Müller, Norbert; Ferrario, Fabio; Fetissow, Sebastian; Grohe, Andreas; Hagen, Thomas; Steger, Ronny; Katzemaikat, Tristan; Ashkenasi, David; Gries, Wolfgang

    2017-02-01

    module thanks to its modular design. This paper's experimental results are based on a trepanning optic attached to the laser module. Alltogether the setup approximately fits in a shoe box and weighs less than 20 kg which allows for direct mounting onto a 3D-gantry system. The oscillating weld performance of the 500 W direct diode laser utilizing a novel trepanning optic is discussed for its application to aluminum/aluminum and aluminum/copper joints.

  9. Optical and transport studies of magnetic semiconductors

    NASA Astrophysics Data System (ADS)

    Shen, Shaoping

    In this thesis, various studies of magneto-transport and magneto-optical effects in III-V and II-V magnetic semiconductors are presented. The magneo-transport study involved the investigation of the anomalous Hall effect (AHE) in (Ga,Mn)As epilayers with low Mn concentration, grown in ultra-high vacuum molecular beam epitaxy (UHV MBE) chamber. Experiments were carried out in National High Magnetic Field Laboratory (NHMFL) on a series of samples with same Mn concentrations (x = 1.4%) but with various Be co-doping levels. We observed a sublinear relationship between the transverse resistivity rhoxy and the longitudinal resistivity rhoxx with a scaling factor n = 0.5, which has not been predicted theoretically. We also investigated the magneto-optical and magnetic properties of two quaternary diluted magnetic semiconductor (DMS) alloys, Cd1- x-yMnxCryTe and Cd1-x-yMnxCo yTe grown by the vertical Bridgman method, with a fixed Mn concentration x ˜ 0.37 and, respectively, with concentrations of Cr in the range 0 < y < 0.07 and Co in the range 0 < y < 0.009. The introduction of Cr and Co leads to very different behaviors, including the occurrence of ferromagnetic order in the case of Cd1-x-yMn xCryTe and several interesting optical transitions for Cd1-x-yMn xCoyTe. We discuss the possible origins of these observed behaviors. Last, we focused on DMS based nano-structures. Magnetic circular dichroism (MCD) studies have been carried out on a series of 1.4 nm thick CdSe:Mn nano-ribbons synthesized via colloidal chemical route. MCD spectra have been used for investigating the Zeeman splitting in these one-dimensional (1D) quantum confined diluted magnetic semiconductor nanostructures. In all samples, a strong MCD signal was found at about 2.9 eV due to a large Zeeman splitting of the exciton confined in the nano-ribbon. The Zeeman splitting is a result of strong sp-d exchange interaction between the electronic holes of the nano-ribbons and localized magnetic moment of Mn2

  10. Optical computed tomography utilizing a rotating mirror and Fresnel lenses: operating principles and preliminary results

    NASA Astrophysics Data System (ADS)

    Xu, Y.; Wuu, Cheng-Shie

    2013-02-01

    The performance of a fast optical computed tomography (CT) scanner based on a point laser source, a small area photodiode detector, and two optical-grade Fresnel lenses is evaluated. The OCTOPUS™-10× optical CT scanner (MGS Research Inc., Madison, CT) is an upgrade of the OCTOPUS™ research scanner with improved design for faster motion of the laser beam and faster data acquisition process. The motion of the laser beam in the new configuration is driven by the rotational motion of a scanning mirror. The center of the scanning mirror and the center of the photodiode detector are adjusted to be on the focal points of two coaxial Fresnel lenses. A glass water tank is placed between the two Fresnel lenses to house gel phantoms and matching liquids. The laser beam scans over the water tank in parallel beam geometry for projection data as the scanning mirror rotates at a frequency faster than 0.1 s per circle. Signal sampling is performed independently of the motion of the scanning mirror, to reduce the processing time for the synchronization of the stepper motors and the data acquisition board. An in-house developed reference image normalization mechanism is added to the image reconstruction program to correct the non-uniform light transmitting property of the Fresnel lenses. Technical issues with regard to the new design of the scanner are addressed, including projection data extraction from raw data samples, non-uniform pixel averaging and reference image normalization. To evaluate the dosimetric accuracy of the scanner, the reconstructed images from a 16 MeV, 6 cm × 6 cm electron field irradiation were compared with those from the Eclipse treatment planning system (Varian Corporation, Palo Alto, CA). The spatial resolution of the scanner is demonstrated to be of sub-millimeter accuracy. The effectiveness of the reference normalization method for correcting the non-uniform light transmitting property of the Fresnel lenses is analyzed. A sub-millimeter accuracy of

  11. Thermo optical study of nematic liquid crystal doped with ferrofluid

    NASA Astrophysics Data System (ADS)

    Jessy P., J.; Shalini, M.; Patel, Nainesh; Sarawade, Pradip; Radha, S.

    2017-05-01

    Liquid crystal composite materials with tunable physical properties are of great scientific interest because of optoelectronic and biomedical applications. We report our study of modified optical properties of 5CB Nematic Liquid Crystal (NLC) by doping with ferrofluid at low concentrations of 0.1% by the investigation of thermo optic behaviour. The observed sensitivity of optical response in ferrofluid doped NLC is expected to pave way for several thermo-optic applications.

  12. Utility of optical coherence tomography in a case of bilateral congenital macular coloboma.

    PubMed

    Muñoz de Escalona Rojas, José Enrique; Quereda Castañeda, Aurora; García García, Olga

    2016-09-01

    Macular coloboma is a congenital defect of the retina and choroid in the macular region. It may appear due to an intrauterine inflammation or a developmental abnormality. Familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) is a result of malformation of the renal tubule. Its combination with ocular manifestations may be genetic, specifically in case of claudin-19 (CLDN-19) gene mutations. The combination of FHHNC and ocular manifestations is not always present in these patients. Optical coherence tomography (OCT) helps us diagnose this condition by allowing us to evaluate and confirm the absence of retina layers without histological examination. Although genetic testing is necessary to diagnose mutational alterations of the CLDN-19 gene, in our case, it was not necessary to diagnose the FHHNC patient with macular coloboma, since the diagnosis of ocular damage had been already accurately established by the OCT.

  13. Utility of optical coherence tomography in a case of bilateral congenital macular coloboma

    PubMed Central

    Muñoz de Escalona Rojas, José Enrique; Quereda Castañeda, Aurora; García García, Olga

    2016-01-01

    Macular coloboma is a congenital defect of the retina and choroid in the macular region. It may appear due to an intrauterine inflammation or a developmental abnormality. Familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) is a result of malformation of the renal tubule. Its combination with ocular manifestations may be genetic, specifically in case of claudin-19 (CLDN-19) gene mutations. The combination of FHHNC and ocular manifestations is not always present in these patients. Optical coherence tomography (OCT) helps us diagnose this condition by allowing us to evaluate and confirm the absence of retina layers without histological examination. Although genetic testing is necessary to diagnose mutational alterations of the CLDN-19 gene, in our case, it was not necessary to diagnose the FHHNC patient with macular coloboma, since the diagnosis of ocular damage had been already accurately established by the OCT. PMID:27853022

  14. Video rate passive millimeter-wave imager utilizing optical upconversion with improved size, weight, and power

    NASA Astrophysics Data System (ADS)

    Martin, Richard D.; Shi, Shouyuan; Zhang, Yifei; Wright, Andrew; Yao, Peng; Shreve, Kevin P.; Schuetz, Christopher A.; Dillon, Thomas E.; Mackrides, Daniel G.; Harrity, Charles E.; Prather, Dennis W.

    2015-05-01

    In this presentation we will discuss the performance and limitations of our 220 channel video rate passive millimeter wave imaging system based on a distributed aperture with optical upconversion architecture. We will cover our efforts to reduce the cost, size, weight, and power (CSWaP) requirements of our next generation imager. To this end, we have developed custom integrated circuit silicon-germanium (SiGe) low noise amplifiers that have been designed to efficiently couple with our high performance lithium niobate upconversion modules. We have also developed millimeter wave packaging and components in multilayer liquid crystal polymer (LCP) substrates which greatly improve the manufacturability of the upconversion modules. These structures include antennas, substrate integrated waveguides, filters, and substrates for InP and SiGe mmW amplifiers.

  15. Single step full volumetric reconstruction optical coherence tomography utilizing compressive sensing

    NASA Astrophysics Data System (ADS)

    Chen, Luoyang; Liu, Jiansheng; cheng, Jiangtao; Liu, Haitao; Zhou, Hongwen

    2017-03-01

    3D optical coherence tomography imaging (OCT) combined with compressive sensing (CS) has been proved to be an attractive and effective tool in a variety of fields, such as medicine and biology. To achieve high quality imaging while using as less CS sampling rate as possible is the goal of this approach. Here we present an innovative single step fully 3D CS-OCT volumetric image recovery method, in which 3D OCT volumetric image of the object is compressively sampled via our proposed CS coding strategies in all three dimensions while its sparsity is simultaneously taken into consideration in every direction. The object can be directly recovered as the whole volume reconstruction via our advanced full 3D CS reconstruction algorithm. The numerical simulations of a human retina OCT volumetric image reconstruction by our method demonstrate a PSNR of as high as 38dB at a sampling rate of less than 10%.

  16. On the relative utility of infrared (IR) versus terahertz (THz) for optical sensors

    NASA Astrophysics Data System (ADS)

    Johnson, T. J.; Valentine, N. B.; Gassman, P. L.; Atkinson, D. A.; Sharpe, S. W.; Williams, Steven D.

    2007-09-01

    Pacific Northwest National Laboratory (PNNL) has active programs investigating the optical absorption strengths of several types of molecules including toxic industrial chemicals (TICs), microbiological threats such as bacteria, as well as explosives such as RDX, PETN and TNT. While most of our work has centered on the mid-infrared domain (600 to 6,500 cm-1), more recent work has also included work in the far-infrared, also called the terahertz (THz) region (500 to ~8 cm-1). Using Fourier transform infrared spectroscopy, we have been able to compare the relative, and in some cases absolute, IR/THz cross sections of a number of species in the solid and liquid phases. The relative band strengths of a number of species of interest are discussed in terms of both experimental and computational results.

  17. Physical Characterization of Solid-Liquid Slurries at High Weight Fractions Utilizing Optical and Ultrasonic Methods

    SciTech Connect

    Burgess, Lloyd W.

    2005-06-01

    The goal of this proposed work is to directly address the need for rapid on-line characterization of the physical properties of HLW slurries during all phases of the remediation process, from in-tank characterization of sediments to monitoring of the concentration, particle size, and degree of agglomeration and gelation of slurries during transport. There are three tasks: (1) develop new optical and acoustic scattering measurements to provide the fundamental science needed for successful device development and implementation, (2) develop theories that describe the interrelationship between wave propagation and the physical properties of the slurry, and (3) perform inversions of the theories and compare them with the experimental measurements to non-intrusively characterize slurries.

  18. On the Relative Utility of Infrared (IR) versus Terahertz (THz) for Optical Sensors

    SciTech Connect

    Johnson, Timothy J.; Valentine, Nancy B.; Gassman, Paul L.; Atkinson, David A.; Sharpe, Steven W.; Williams, Stephen D.

    2007-11-30

    Pacific Northwest National Laboratory (PNNL) has active programs investigating the optical absorption strengths of several types of molecules including toxic industrial chemicals (TICs), microbiological threats such as bacteria, as well as explosives such as RDX, PETN and TNT. While most of our work has centered on the mid-infrared domain (600 to 6,500 cm-1), more recent work has also included work in the far-infrared, also called the terahertz (THz) region (500 to ~8 cm-1). Using Fourier transform infrared spectroscopy, we have been able to compare the relative, and in some cases absolute, IR/THz cross sections of a number of species in the solid and liquid phases. The relative band strengths of a number of species of interest are discussed in terms of both experimental and computational results.

  19. Electro-optic testbed utilizing a dynamic range gated Rayleigh beacon for atmospheric turbulence profiling

    NASA Astrophysics Data System (ADS)

    Zuraski, Steven M.; Fiorino, Steven T.; Beecher, Elizabeth A.; Figlewski, Nathan M.; Schmidt, Jason D.; McCrae, Jack E.

    2016-10-01

    The Photometry Analysis and Optical Tracking and Evaluation System (PANOPTES) Quad Axis Telescope is a unique four axis mount Ritchey-Chretien 24 inch telescope capable of tracking objects through the zenith without axes rotation delay (no Dead Zone). This paper describes enhancement components added to the quad axis mount telescope that will enable measurements supporting novel research and field testing focused on `three-dimensional' characterization of turbulent atmospheres, mitigation techniques, and new sensing modalities. These all support research and operational techniques relating to astronomical imaging and electro-optical propagation though the atmosphere, relative to sub-meter class telescopes in humid, continental environments. This effort will use custom designed and commercial off the shelf hardware; sub-system components discussed will include a wavefront sensor system, a co-aligned beam launch system, and a fiber coupled research laser. The wavefront sensing system has the ability to take measurements from a dynamic altitude adjustable laser beacon scattering spot, a key concept that enables rapid turbulence structure parameter measurements over an altitude varied integrated atmospheric volume. The sub-components are integrated with the overall goal of measuring a height-resolved volumetric profile for the atmospheric turbulence structure parameter at the site, and developing mobile techniques for such measurements. The design concept, part selection optimization, baseline component lab testing, and initial field measurements, will be discussed in the main sections of this paper. This project is a collaborative effort between the Air Force Research Labs Sensors Directorate and the Air Force Institute of Technology Center for Directed Energy.

  20. Studies of the Electro-Optic Effect.

    DTIC Science & Technology

    1983-01-01

    electro - optic effect in crystalline solids has been pursued by employing a tight-binding theory for dielectric susceptibilities. The electronic and lattice contributions to the second-order electro - optic susceptibility have been treated separately and the lattice response of a crystal to an external dc electric field has been investigated in a general formalism. The theory has been specifically applied to the compound, tellurium dioxide. In addition, an experimental determination of the electro - optic coefficient, re, in thallium

  1. Clinical utility of reflex studies in assessing cervical radiculopathy.

    PubMed

    Miller, T A; Pardo, R; Yaworski, R

    1999-08-01

    We prospectively studied the diagnostic utility of upper limb segmental reflexes in patients with suspected cervical radiculopathy (CR). Fifty-three patients (29 men and 24 women), referred for electrodiagnostic testing, were positive for at least one of four clinical criteria for CR: abnormal (1) history, (2) motor (myotomal) examination, (3) sensory (dermatomal) examination, and (4) changes in deep tendon reflexes (DTR). All underwent electrodiagnostic assessment, needle electrode examination (NEE), specialized segmental reflexes (heteronymous and Hoffman's reflexes [H reflexes]), and neuroimaging. The clinical diagnosis was supported in all 32 patients who entered the study with two or more clinical signs for CR. Abnormal NEE was found in 90% of subjects with three clinical signs, 59% with two signs, and only 10% of those with one sign. H reflexes demonstrated a sensitivity of 72% and specificity of 85% for detection of CR and were particularly helpful when forming conclusions in the 21 subjects with only one clinical sign for CR. Specialized segmental H-reflex studies of the upper limb were as sensitive and specific as neuroimaging (magnetic resonance imaging). Copyright 1999 John Wiley & Sons, Inc.

  2. Kauai Island Utility Co-op (KIUC) PV integration study.

    SciTech Connect

    Ellis, Abraham; Mousseau, Tom

    2011-08-01

    This report investigates the effects that increased distributed photovoltaic (PV) generation would have on the Kauai Island Utility Co-op (KIUC) system operating requirements. The study focused on determining reserve requirements needed to mitigate the impact of PV variability on system frequency, and the impact on operating costs. Scenarios of 5-MW, 10-MW, and 15-MW nameplate capacity of PV generation plants distributed across the Kauai Island were considered in this study. The analysis required synthesis of the PV solar resource data and modeling of the KIUC system inertia. Based on the results, some findings and conclusions could be drawn, including that the selection of units identified as marginal resources that are used for load following will change; PV penetration will displace energy generated by existing conventional units, thus reducing overall fuel consumption; PV penetration at any deployment level is not likely to reduce system peak load; and increasing PV penetration has little effect on load-following reserves. The study was performed by EnerNex under contract from Sandia National Laboratories with cooperation from KIUC.

  3. [Utilization of spaceflight technology on medicinal plant study].

    PubMed

    Gao, Wen-yuan; Jia, Wei; Xiao, Pei-gen

    2004-07-01

    Utilization of spaceflight technology will benefit the modernization of Traditional Chinese Medicine study. Many countries, such as USA or Russia, have conducted extensive experimental research with plants in the regenerative life-support system in space stations as well as the research on breeding or chromosomal aberration after spaceflight. The space botany is still in its preliminary stage in our country. Research has mainly been focused on breeding under space-environment. In addition, many experiments have been conducted with the spaceflown plants to investigate the growth, development, biochemical and physiological changes, as well as the inheritance and variation. Little has been done with regard to the facility development to contain the spaceflying seeds and no research has been reported on plant growth in spacecrafts. Medicinal plant study has certain characteristics and advantages in our country where small biological vessels are developed for the spaceflown seeds, which are then distinguished to microgravity group and radiation exposed group with analytical instrument. However, research has been carried out in medicinal plant breeding or inheritance. In future research, more effort should be directed to the study of medicinal plants as an important link of a future biological life support system as well as to the health care of astronauts by.

  4. Study of methods for direct optical address of integrated optical circuits

    NASA Technical Reports Server (NTRS)

    Wood, V. E.; Verber, C. M.

    1979-01-01

    Methods for introducing optical information directly, without intervening recording and storage steps, into integrated optical data-processing devices are surveyed. The information is taken to be in the form of a one-dimensional variation of intensity across the beam. Physical phenomena that may be utilized are evaluated, and the most suitable presently known classes of materials for exploitation of each type of interaction are discussed. A variety of possible device configurations are suggested and general principles are outlined whereby many more device types can be generated. A simple experimental device was demonstrated and its operation was analyzed.

  5. Utility of transplantation in studying adipocyte biogenesis and function

    PubMed Central

    Zhang, Yiying

    2009-01-01

    Adipose tissue plays important roles in the regulation of energy homeostasis and metabolism. Two features distinguish adipose tissue from other organs - the ability to greatly expand its mass, via increases in cell size and/or number, and the wide anatomical distribution. While adipose tissue function is greatly affected by adipocyte size and anatomic location, regulations of adipocyte size, number, and body fat distribution are poorly understood. Transplantation of either mature adipose tissue or adipocyte progenitor cells has been used in studying adipocyte function and biogenesis. In this review, we will attempt to summarize methodological considerations for transplantation, including selections of donor material, transplantation site and the length of transplantation study, as well as effects of these factors and vascularization and innervation on the function of transplants. Specific studies are also reviewed to illustrate the utility of adipose tissue transplants in studying adipose tissue function and biogenesis. The focus is on studies in three areas: 1) use of transplants in demonstrating adipose tissue function, such as effects of adipose tissue transplants on metabolism and energy homeostasis of the recipient animals and depot-specific differences in adipose tissue function; 2) use of transplantation to dissect direct or cell-autonomous from indirect or non cell-autonomous effects of leptin signaling and sex on adipocyte size; 3) use of transplantation in the identification of adipocyte progenitor cells and lineage analysis. Finally, future applications of transplantation in studying depot-specific adipocyte biogenesis, and genetic and hormonal effects of sex and age on adipocyte biogenesis and function are discussed. PMID:19733623

  6. A Study of Synchronization Techniques for Optical Communication Systems

    NASA Technical Reports Server (NTRS)

    Gagliardi, R. M.

    1975-01-01

    The study of synchronization techniques and related topics in the design of high data rate, deep space, optical communication systems was reported. Data cover: (1) effects of timing errors in narrow pulsed digital optical systems, (2) accuracy of microwave timing systems operating in low powered optical systems, (3) development of improved tracking systems for the optical channel and determination of their tracking performance, (4) development of usable photodetector mathematical models for application to analysis and performance design in communication receivers, and (5) study application of multi-level block encoding to optical transmission of digital data.

  7. Electric Field Measurements of the Capacitively Coupled Magnetized RF Sheath Utilizing Passive Optical Emission Spectroscopy

    NASA Astrophysics Data System (ADS)

    Martin, Elijah Henry

    A major challenge facing magnetic confinement fusion is the implementation of reliable plasma heating systems. Ion cyclotron resonance heating (ICRH) is a key technique utilized to achieve the ion temperatures necessary for desirable fusion reaction rates. ICRH systems are designed to couple energy into the core plasma ions through a resonant interaction with an electromagnetic wave in the radio frequency range. The interaction of the wave with the scrape off layer plasma establishes an electric field which terminates directly on the plasma facing surfaces and is referred to as the near-field. In order to bridge the gap between the theoretical and actual performance of ICRF antennas, experimental measurement of this electric field is highly desired. However, due to the large amount of power launched by ICRF antennas only non-local measurements have thus far been obtained. The research presented in this dissertation is centered on the development of a non-perturbative diagnostic to locally measure the near-field with high spatial and temporal resolution. The main objective of the research presented in this dissertation is to develop and validate a spectroscopic diagnostic capable of measuring local time periodic electric fields. The development phase of the diagnostic consisted of atomic physics formulation and was carried out in two steps. The first involved the calculation of the electronic structure of the one and two-electron atom utilizing the hydrogenic wave function. The second involved the calculation of the spectral line profile based on the electric dipole connection operator. The validate phase of the diagnostic consisted of implementation of the atomic physics to measure the electric field topology associated with the capacitively coupled magnetized RF sheath using passive OES. The experimental measurements are then compared to a simple one-dimensional analytical model providing the validation of the developed atomic physics.

  8. Optical computed tomography utilizing a rotating mirror and Fresnel lenses: operating principles and preliminary results.

    PubMed

    Xu, Y; Wuu, Cheng-Shie

    2013-02-07

    The performance of a fast optical computed tomography (CT) scanner based on a point laser source, a small area photodiode detector, and two optical-grade Fresnel lenses is evaluated. The OCTOPUS™-10× optical CT scanner (MGS Research Inc., Madison, CT) is an upgrade of the OCTOPUS™ research scanner with improved design for faster motion of the laser beam and faster data acquisition process. The motion of the laser beam in the new configuration is driven by the rotational motion of a scanning mirror. The center of the scanning mirror and the center of the photodiode detector are adjusted to be on the focal points of two coaxial Fresnel lenses. A glass water tank is placed between the two Fresnel lenses to house gel phantoms and matching liquids. The laser beam scans over the water tank in parallel beam geometry for projection data as the scanning mirror rotates at a frequency faster than 0.1 s per circle. Signal sampling is performed independently of the motion of the scanning mirror, to reduce the processing time for the synchronization of the stepper motors and the data acquisition board. An in-house developed reference image normalization mechanism is added to the image reconstruction program to correct the non-uniform light transmitting property of the Fresnel lenses. Technical issues with regard to the new design of the scanner are addressed, including projection data extraction from raw data samples, non-uniform pixel averaging and reference image normalization. To evaluate the dosimetric accuracy of the scanner, the reconstructed images from a 16 MeV, 6 cm × 6 cm electron field irradiation were compared with those from the Eclipse treatment planning system (Varian Corporation, Palo Alto, CA). The spatial resolution of the scanner is demonstrated to be of sub-millimeter accuracy. The effectiveness of the reference normalization method for correcting the non-uniform light transmitting property of the Fresnel lenses is analyzed. A sub

  9. Optimization of training sequence for DFT-spread DMT signal in optical access network with direct detection utilizing DML.

    PubMed

    Li, Fan; Li, Xinying; Yu, Jianjun; Chen, Lin

    2014-09-22

    We experimentally demonstrated the transmission of 79.86-Gb/s discrete-Fourier-transform spread 32 QAM discrete multi-tone (DFT-spread 32 QAM-DMT) signal over 20-km standard single-mode fiber (SSMF) utilizing directly modulated laser (DML). The experimental results show DFT-spread effectively reduces Peak-to-Average Power Ratio (PAPR) of DMT signal, and also well overcomes narrowband interference and high frequencies power attenuation. We compared different types of training sequence (TS) symbols and found that the optimized TS for channel estimation is the symbol with digital BPSK/QPSK modulation format due to its best performance against optical link noise during channel estimation.

  10. Study of Linearization of Optical Polymer Modulators

    DTIC Science & Technology

    2004-02-01

    To improve the Spur Free Dynamic Range of analog electro - optic modulators in the >10 GHz regime, techniques for improving the linearity of these...devices must be developed. This report discusses an investigation into electro - optic directional couplers that use variable coupling in polymer-based

  11. Chiro-optic and nonlinear optical studies of bridged triarylamine heterohelicenes; A DFT study

    NASA Astrophysics Data System (ADS)

    Islam, Nasarul; Pandith, Altaf Hussain

    2017-08-01

    Density Functional Theory at B3PW91/6-311G (d, p) level was employed to analyze the spectral properties and nonlinear optical response of the oxo and thia-bridged triarylamine heterohelicenes. The energy calculations of optimized geometries reveals that the M and P isomeric forms of heterohelicenes of 1, 2, 3 and 4 are enantiomers, while as for 5, 6 and 7 they are atropisomers. The simulated Infrared and Vibrational circular dichroism spectra in the mid-infrared region (1300-1650 cm-1) display peaks, having contribution from out-of-phase stretching of the three fused aromatic rings and contribution from the three Nsbnd C bond stretching. In addition to these peaks M-7 displays peak corresponds to bending of Hsbnd Csbnd H of terminal methoxy group. In this study we have observed the oxo-bridged heterohelicenes displays higher values of hyperpolarizability as compared to thia-bridged heterohelicenes. In case of M-5, M-6 and M-7 the calculation reveals that with increase in electron donating capacity of substituent the hyperpolarizability increase due to decrease in optical band gap. Therefore, the oxo- and thia-bridged heterohelicenes can act as good raw material for nonlinear optical device and their nonlinear optical response can be enhanced by the extension in π-conjugation or addition of electron donating substituents.

  12. Optical Amplifier with Flat-Gain and Wideband Operation Utilizing Highly Concentrated Erbium-Doped Fibers

    NASA Astrophysics Data System (ADS)

    Hamida, B. A.; Cheng, X. S.; Naji, A. W.; Ahmad, H.; Al-Khateeb, W.; Khan, S.; Harun, S. W.

    In this paper, we proposed a flat-gain and wide-band erbium doped fiber amplifier (EDFA) using two chirped fiber Bragg grating (CFBG) in serial configuration for double-pass operation. The amplifier consists of two sections of Erbium-doped fiber (EDF) operating in C-band and L-band respectively. A CFBG is used in each section to reflect the amplified signal back to the active area so that the overall gain spectrum can be enhanced and flattened. It is also observed that the gain of the amplifier produces a relatively higher gain with the Bismuth-based EDF (Bi-EDF) in the first stage compared to that of silica-based EDF (Si-EDF), especially in a longer wavelength region. The small signal gain of more than 19 dB is obtained within a wavelength region from 1545 to 1605 nm by the use of Bi-EDF with a small noise figure penalty. With a Si-EDF, the flat gain spectrum is observed within a wavelength region ranging from 1535 nm to 1605 nm with a gain variation of less than 2 dB at input signal of 0 dBm. This shows that the proposed serial double-pass amplifier may find its broad applications in wavelength division multiplexing long-haul systems as well as local optical networks.

  13. Utilization of optical image data from the Advanced Test Accelerator (ATA)

    SciTech Connect

    Chambers, F.W.; Kallman, J.S.; Slominski, M.E.; Chong, Y.P.; Donnelly, D.; Cornish, J.P.

    1987-01-01

    Extensive use is made of optical diagnostics to obtain information on the 50-MeV, 10-kA, 70-ns pulsed-electron beam produced by the Advanced Test Accelerator (ATA). Light is generated by the beam striking a foil inserted in the beamline or through excitation of the gas when the beamline is filled with air. The emitted light is collected and digitized. Two-dimensional images are recorded by either a gated framing camera or a streak camera. Extraction of relevant beam parameters, such as current density, current, and beam size, requires an understanding of the physics of the light-generation mechanism and an ability to handle and properly exploit a large digital database of image data. We will present a brief overview of the present understanding of the light-generation mechanisms in foil and gas, with emphasis on experimental observations and trends. We will review our data management and analysis techniques and indicate successful approaches for extracting beam parameters.

  14. Utility of an optically-based, micromechanical system for printing collagen fibers

    PubMed Central

    Paten, Jeffrey A.; Tilburey, Graham E.; Molloy, Eileen A.; Zareian, Ramin; Trainor, Christopher V.

    2013-01-01

    Collagen's success as the principal structural element in load-bearing, connective tissue has motivated the development of numerous engineering approaches designed to recapitulate native fibril morphology and strength. It has been shown recently that collagen fibers can be drawn from monomeric solution through a fiber forming buffer (FFB), followed by numerous additional treatments in a complex serial process. However, internal fibril alignment, packing and resultant mechanical behavior of the fibers have not been optimized and remain inferior to native tissue. Further, no system has been developed which permits simultaneous application of molecular crowding, measurement of applied load, and direct observation of polymerization dynamics during fiber printing. The ability to perform well-controlled investigations early in the process of fiber formation, which vary single input parameters (i.e. collagen concentration, crowding agent concentration, draw rate, flow rate, temperature, pH, etc.) should substantially improve fiber morphology and strength. We have thus designed, built, and tested a versatile, in situ, optically-based, micromechanical assay and fiber printing system which permits the correlation of parameter changes with mechanical properties of fibers immediately after deposition into an FFB. We demonstrate the sensitivity of the assay by detecting changes in the fiber mechanics in response to draw rate, collagen type, small changes in the molecular crowding agent concentration and to variations in pH. In addition we found the ability to observe fiber polymerization dynamics leads to intriguing new insights into collagen assembly behavior. PMID:23352045

  15. Mesoscale modeling of optical turbulence (C2n) utilizing a novel physically-based parameterization

    NASA Astrophysics Data System (ADS)

    He, Ping; Basu, Sukanta

    2015-09-01

    In this paper, we propose a novel parameterization for optical turbulence (C2n) simulations in the atmosphere. In this approach, C2n is calculated from the output of atmospheric models using a high-order turbulence closure scheme. An important feature of this parameterization is that, in the free atmosphere (i.e., above the boundary layer), it is consistent with a well-established C2n formulation by Tatarskii. Furthermore, it approaches a Monin-Obukhov similarity-based relationship in the surface layer. To test the performance of the proposed parameterization, we conduct mesoscale modeling and compare the simulated C2n values with those measured during two field campaigns over the Hawaii island. A popular regression-based approach proposed by Trinquet and Vernin (2007) is also used for comparison. The predicted C2n values, obtained from both the physically and statistically-based parameterizations, agree reasonably well with the observational data. However, in the presence of a large-scale atmospheric phenomenon (a breaking mountain wave), the physically-based parameterization outperforms the statistically-based one.

  16. Medical devices utilizing optical fibers for simultaneous power, communications and control

    DOEpatents

    Fitch, Joseph P.; Matthews, Dennis L.; Hagans, Karla G.; Lee, Abraham P.; Krulevitch, Peter; Benett, William J.; Clough, Robert E.; DaSilva, Luiz B.; Celliers, Peter M.

    2003-06-10

    A medical device is constructed in the basic form of a catheter having a distal end for insertion into and manipulation within a body and a proximal end providing for a user to control the manipulation of the distal end within the body. A fiberoptic cable is disposed within the catheter and having a distal end proximate to the distal end of the catheter and a proximal end for external coupling of laser light energy. A laser-light-to-mechanical-power converter is connected to receive light from the distal end of the fiber optic cable and may include a photo-voltaic cell and an electromechanical motor or a heat-sensitive photo-thermal material. An electronic sensor is connected to receive electrical power from said distal end of the fiberoptic cable and is connected to provide signal information about a particular physical environment and communicated externally through the fiberoptic cable to the proximal end thereof. A mechanical sensor is attached to the distal end of the fiberoptic cable and connected to provide light signal information about a particular physical environment and communicated externally through the fiberoptic cable.

  17. Studies of Beam Expansion and Distributed Bragg Reflector Lasers for Fiber Optics and Optical Signal Processing.

    DTIC Science & Technology

    1981-03-03

    block number) Separate studies were performed on beam expansion and on Distributed Bragg Reflector ( DBR ) lasers preliminary to monolithic integration on...Reflector ( DBR ) laser is a light source compatible with monolithic integrated optics. In the DBR laser one or both cleaved endfaces of a typical double...cleave as a laser cavity mirror. The DBR laser can be used as an integrated optics light source for integrated optical circuits. In this report we

  18. A study of high repetition rate pulse generation and all-optical add/drop multiplexing

    NASA Astrophysics Data System (ADS)

    Chen, Hongmin

    Ultra high-speed optical time-division-multiplexed (OTDM) transmission technologies are essential for the construction of ultra high-speed all-optical networks needed in the information era. In this Ph. D thesis dissertation, essential mechanisms associated with ultra high speed OTDM transmission systems, such as, high speed ultra short pulse generation, all optical demultiplexing and all optical add/drop multiplexing, have been studied. Both experimental demonstrations and numerical simulations have been performed. In order to realize high-speed optical TDM systems, high repetition rate, ultra short pulses are needed. A rational harmonic mode-locked ring fiber laser has been used to produce ultrashort pulses, the pulse jitter will be eliminated using a Phase-Locked-Loop (PLL), and the self-pulsation has been suppressed using a semiconductor optical amplifier (SOA). Sub pico-second pulses are very important for all optical sampling in the ultrahigh-speed OTDM transmission system. In this thesis, a two stage compression scheme utilizing the nonlinearity and dispersion of the optical fibers has been constructed and used to compress the gain switched DFB laser pulses. Also a nonlinear optical loop mirror has been constructed to suppress the wings associated with nonlinear compression. Pedestal free, transform-limited pulses with pulse widths in range of 0.2 to 0.4 ps have been generated. LiNbO3 modulators play a very important role in fiber optical communication systems. In this thesis, LiNbO3 modulators have been used to perform high repetition rate pulse generation, all optical demultiplexing and all optical add/drop for the TDM transmission system.

  19. Decontamination trade study for the Light Duty Utility Arm

    SciTech Connect

    Rieck, R.H.

    1994-09-29

    Various methods were evaluated for decontaminating the Light Duty Utility Arm (LDUA). Physical capabilities of each method were compared with the constraints and requirements for the LDUA Decontamination System. Costs were compared and a referred alternative was chosen.

  20. Module greenhouse with high efficiency of transformation of solar energy, utilizing active and passive glass optical rasters

    SciTech Connect

    Korecko, J.; Jirka, V.; Sourek, B.; Cerveny, J.

    2010-10-15

    Since the eighties of the 20th century, various types of linear glass rasters for architectural usage have been developed in the Czech Republic made by the continuous melting technology. The development was focused on two main groups of rasters - active rasters with linear Fresnel lenses in fixed installation and with movable photo-thermal and/or photo-thermal/photo-voltaic absorbers. The second group are passive rasters based on total reflection of rays on an optical prism. During the last years we have been working on their standardization, exact measuring of their optical and thermal-technical characteristics and on creation of a final product that could be applied in solar architecture. With the project supported by the Ministry of Environment of the Czech Republic we were able to build an experimental greenhouse using these active and passive optical glass rasters. The project followed the growing number of technical objectives. The concept of the greenhouse consisted of interdependence construction - structural design of the greenhouse with its technological equipment securing the required temperature and humidity conditions in the interior of the greenhouse. This article aims to show the merits of the proposed scheme and presents the results of the mathematical model in the TRNSYS environment through which we could predict the future energy balance carried out similar works, thus optimizing the investment and operating costs. In this article description of various technology applications for passive and active utilization of solar radiation is presented, as well as some results of short-term and long-term experiments, including evaluation of 1-year operation of the greenhouse from the energy and interior temperature viewpoints. A comparison of the calculated energy flows in the greenhouse to real measured values, for verification of the installed model is also involved. (author)

  1. Utilization of date syrup as a tablet binder, comparative study

    PubMed Central

    Alanazi, Fars Kaed

    2010-01-01

    The aim of this study was to investigate the possibility of using dates syrup as a tablet binder. Dates syrup (40%, 50%, 60% w/w dates syrup:water) was utilized for the granulation of sodium bicarbonate and calcium carbonate as examples for water-soluble and water-insoluble materials; correspondingly. Those two materials represent examples of bulky drugs as well. Starch paste (10% w/w starch in water) and sucrose syrup (50% w/w sucrose in water), the well-known tablet binders, were used in the granulation of the same materials for the sake of comparison. The granulations were evaluated with regard to particle size and particle size distribution, granule strength, bulk density, flowability, moisture content and compression behavior. In addition, tablets prepared and evaluated from these granules. Taste and flavor of the prepared tablet have been tested by seven healthy volunteers. Within the scope of this work, dates syrup showed excellent properties as a tablet binder in comparison to starch paste or sucrose syrup for the granulation of both water-soluble and water-insoluble materials. Also, better flavoring and masking taste have been noticed from an evaluation by human volunteers demonstrating the usefulness of the date syrup as sweetener and flavoring the tablets in addition to its use as binder. PMID:23960724

  2. Turbidity study of solar ponds utilizing seawater as salt source

    SciTech Connect

    Li, Nan; Sun, Wence; Shi, Yufeng; Yin, Fang; Zhang, Caihong

    2010-02-15

    A series of experiments were conducted to study the turbidity reduction in solar ponds utilizing seawater as salt source. The experiment on the turbidity reduction efficiency with chemicals indicates that alum (KAl(SO{sub 4}){sub 2}.12H{sub 2}O) has a better turbidity control property because of its strongly flocculating and also well depressing the growing of algae and bacteria in the seawater. In comparison with bittern and seawater, our experiment shows that the residual brine after desalination can keep limpidity for a long time even without any chemical in it. Experiments were also conducted on the diffusion of turbidity and salinity, which show that the turbidity did not diffuse upwards in the solution. In the experiment on subsidence of soil in the bittern and saline with the same salinity, it was found that soil subsided quite quickly in the pure saline water, but very slowly in the bittern. In this paper we also proposed an economical method to protect the solar pond from the damage of rain. Finally, thermal performance of a solar pond was simulated in the conditions of different turbidities using a thermal diffusion model. (author)

  3. A study on cavity collapse for utilizing green implosion energy

    NASA Astrophysics Data System (ADS)

    Lee, Hyunhee; Gojani, Ardian; Han, Tae-Hee; Yoh, Jack

    2009-06-01

    The mechanical energy generated by laser-induced implosion and the dynamics between non-condensable gas and liquid are studied experimentally and numerically. We have designed a micro implosion piston (MIP) to utilize the energy of implosion for inducing a piston motion. The MIP has the shape of a cone and is filled with liquid at room temperature and a high pressure (˜ 6 bars). Focusing of a high power laser pulse inside the MIP leads to creation of several bubbles that expand and collapse with successive rebounds. The bubble-liquid interaction develops a micro- jet that destroys the symmetry of the bubble. This bubble implosion motion, induced by the pressure gradient across the cavity wall produces high pressures wave within a few nanoseconds. These pressure waves are affected by different conditions such as the distance between the bubble and piston head, the dimension of the MIP, and the pressure at which the MIP is driven. The radius of the bubble is measured by double exposure photography, while pressure histories are measured by hydrophones. We investigate the relationship between the radius of the bubble, the overpressure of the secondary shock wave and the motion of the micro piston, and compare it to numerical simulations. The aim is to reach a state inside the MIP that would cause a sustainable and efficient motion of piston through cavity collapse induced high pressure pulses.

  4. Promising Rapid Access High-Capacity Mass Storage Technique For Diagnostic Information Utilizing Optical Disc

    NASA Astrophysics Data System (ADS)

    Colby, R. L.; Bartuska, A. J.; Herzog, D. G.

    1982-01-01

    The optical disc has become a new technique for mass digital data storage of X-ray images from examinations and films in todays hospitals. Up to 36,000 X-ray images can be stored on one side of a 12-inch disc by melting holes 0.015 mils in size in an ablative material such as tellerium with a laser beam. This unique characteristic makes the disc suitable for storage and retrieval of X-rays in a record and playback system in either a single disc or multiple disc "jukebox" configuration. Doctors, nurses, technicians and other hospital personnel can call up a particular X-ray in less than 0.6 of a second in an on-line single disc system and up to less than 6 seconds in an on-line "jukebox" system. The jukebox is configured to hold up to 100 discs, thus storing 3,600,000 X-rays in hospitals with a bed size of greater than 500. The estimated exposed films on file in those hospitals is 327,400,000 and the estimated annual X-ray exams are 44,300. Thus, a single disc system could be used for an all electronic X-ray scanning system for annual X-ray exams. The jukebox configuration, which has expansion capability for servicing multiple simultaneous user request, can be applied to large archival mass storage. These systems could store the existing exposed films in hospitals with bed size greater than 500 at record and playback data rates of 50 Mb/s with access times of less than 15 seconds.

  5. Proposal for all-optical switchable and tunable ultrawideband monocycle generation utilizing SOA wavelength conversion and time delay

    NASA Astrophysics Data System (ADS)

    Hu, Zhefeng; Xu, Jianhui; Hou, Min

    2017-03-01

    An all-optical ultrawideband monocycle generator based on wavelength conversion in a semiconductor optical amplifier (SOA) and optical tunable delay in an optical delay line (ODL) is proposed and simulated. The system achieves optically switchable in pulse polarity and tunable in both the pulsewidth and radio frequency (RF) spectrum.

  6. An Exploration of the Utility of a Knowledge Utilization Framework to Study the Gap between Reading Disabilities Research and Practice

    ERIC Educational Resources Information Center

    Davidson, Katherine; Nowicki, Elizabeth

    2012-01-01

    This pre-pilot study explored the usefulness of a knowledge utilization framework comprised of Knott and Wildavsky's (1980) seven stages of knowledge use and Stone's (2002) three routes to knowledge use to investigate the gap between reading disabilities research and teachers' self-reported use of that research. Semi-structured interviews of ten…

  7. An Exploration of the Utility of a Knowledge Utilization Framework to Study the Gap between Reading Disabilities Research and Practice

    ERIC Educational Resources Information Center

    Davidson, Katherine; Nowicki, Elizabeth

    2012-01-01

    This pre-pilot study explored the usefulness of a knowledge utilization framework comprised of Knott and Wildavsky's (1980) seven stages of knowledge use and Stone's (2002) three routes to knowledge use to investigate the gap between reading disabilities research and teachers' self-reported use of that research. Semi-structured interviews of ten…

  8. Studies of beam expansion and distributed Bragg reflector lasers for fiber optics and optical signal processing

    NASA Astrophysics Data System (ADS)

    Garmire, E. M.

    1981-03-01

    Separate studies were performed on beam expansion and on distributed Bragg Reflector (DBR) lasers preliminary to monolithic integration on GaAs substrates. These components are proposed for use in optical signal processing, for fiber optic sources and for high brightness lasers.

  9. Optical studies of dynamical processes in disordered materials

    SciTech Connect

    Yen, W.M.

    1990-12-01

    Our research continues to focus on the study of the structure and the dynamic behavior of insulating solids which can be activated optically. We have been particularly interested in the physical processes which produce relaxation and energy transfer in the optical excited states. Our studies have been based principally on optical laser spectroscopic techniques which reveal a more detailed view of the materials of interest and which will ultimately lead to the development of more efficient optoelectronic materials. 13 refs.

  10. A quantitative study of optical mapping surfaces by atomic force microscopy and restriction endonuclease digestion assays.

    PubMed

    Reed, J; Singer, E; Kresbach, G; Schwartz, D C

    1998-05-15

    Many new techniques in biomolecular chemistry and genomic analysis require the immobilization of molecular reagents on specially prepared surfaces. However, the process of molecular fixation often interferes with or precludes the use of standard in vitro biochemical assays. Optical mapping is an emergent technology for genomic analysis which relies on the biochemical activity of DNA fixed to silanized glass surfaces. Optical mapping surfaces have been shown to be compatible with restriction endonucleases and a variety of DNA polymerases. The essential properties of biochemically active surfaces are poorly understood in most of the current technologies which utilize molecular fixation, including optical mapping. The purpose of this study is to use the powerful technique of atomic force microscopy, in combination with informative enzymatic assays, to correlate biochemical activity with microscopic surface structure. The results presented provide meaningful insight into the effect of surface preparation on the biochemical accessibility of surface-bound molecules. Novel analysis which may facilitate the automation of optical mapping is presented.

  11. Surface diffusion studies by optical diffraction techniques

    SciTech Connect

    Xiao, X.D.

    1992-11-01

    The newly developed optical techniques have been combined with either second harmonic (SH) diffraction or linear diffraction off a monolayer adsorbate grating for surface diffusion measurement. Anisotropy of surface diffusion of CO on Ni(l10) was used as a demonstration for the second harmonic dim reaction method. The linear diffraction method, which possesses a much higher sensitivity than the SH diffraction method, was employed to study the effect of adsorbate-adsorbate interaction on CO diffusion on Ni(l10) surface. Results showed that only the short range direct CO-CO orbital overlapping interaction influences CO diffusion but not the long range dipole-dipole and CO-NI-CO interactions. Effects of impurities and defects on surface diffusion were further explored by using linear diffraction method on CO/Ni(110) system. It was found that a few percent S impurity can alter the CO diffusion barrier height to a much higher value through changing the Ni(110) surface. The point defects of Ni(l10) surface seem to speed up CO diffusion significantly. A mechanism with long jumps over multiple lattice distance initiated by CO filled vacancy is proposed to explain the observed defect effect.

  12. Surface diffusion studies by optical diffraction techniques

    SciTech Connect

    Xiao, Xu -Dong

    1992-11-01

    The newly developed optical techniques have been combined with either second harmonic (SH) diffraction or linear diffraction off a monolayer adsorbate grating for surface diffusion measurement. Anisotropy of surface diffusion of CO on Ni(l10) was used as a demonstration for the second harmonic dim reaction method. The linear diffraction method, which possesses a much higher sensitivity than the SH diffraction method, was employed to study the effect of adsorbate-adsorbate interaction on CO diffusion on Ni(l10) surface. Results showed that only the short range direct CO-CO orbital overlapping interaction influences CO diffusion but not the long range dipole-dipole and CO-NI-CO interactions. Effects of impurities and defects on surface diffusion were further explored by using linear diffraction method on CO/Ni(110) system. It was found that a few percent S impurity can alter the CO diffusion barrier height to a much higher value through changing the Ni(110) surface. The point defects of Ni(l10) surface seem to speed up CO diffusion significantly. A mechanism with long jumps over multiple lattice distance initiated by CO filled vacancy is proposed to explain the observed defect effect.

  13. Measurement and modeling of optical performance of wire grids and liquid-crystal displays utilizing grid polarizers.

    PubMed

    Sergan, Tatiana; Lavrentovich, Marina; Kelly, Jack; Gardner, Eric; Hansen, Douglas

    2002-09-01

    We studied the optical performance of a reflective wire-grid polarizer designed for visible light. The polarizer reflects E polarization and transmits H polarization with low losses. The studies of transmission and reflectivity of nonpolarized and polarized light from single grids and stacked grids show that the optical performance of wire-grid polarizers can be adequately described by representing the polarizer as an effective uniaxial medium with anisotropic absorption. The description facilitates the incorporation of the polarizers in modeling procedures widely used in the design of liquid-crystal devices. We present the modeling and measurement results of twisted-nematic devices with wire-grid polarizers serving simultaneously as reflective polarizers, alignment layers, and back electrodes. The application of wire-grid polarizers for reflective liquid-crystal devices provides brightness enhancement, high contrast ratio at wide viewing angles, and elimination of viewing parallax.

  14. Novel optical study and application on iii-nitrides

    NASA Astrophysics Data System (ADS)

    Sun, Guan

    GaN and its heterostuctures have been intensively studied for wide applications. For example, InGaN/GaN quantum wells (QWs) have been used as active materials for light emitting diodes (LEDs) and laser diodes (LDs) from blue to green region while GaN/AlGaN QWs have been used for ultraviolet region. Meanwhile, nitrides are also very important materials for power electronic devices since such materials hold various advantage over competing semiconductor materials such as Si, GaAs, etc. Due to the above reasons, we believe GaN and its heterostructures will play crucial role for optics and electronics devices as silicon does for electronics. Thus, it is worthwhile to explore possibility of achieving different kinds of newapplications on GaN. This dissertation is focused on optical study on GaN based materials, including GaN thin film, InGaN/GaN QWs, InGaN dot-in-a-wire nanostructures, GaN/AlN QWs, etc. More specifically, in Chapter 2, we report efficient broadband terahertz (THz) generated in InGaN/GaN heterostructures due to spontaneous dipole radiation utilizing the strong internal field. Considering the normalized power, InGaN/GaN heterostructure is one of the most efficient materials for broadband THz generation. The correlated behavior between THz and photoluminescence (PL) has also been discussed. In Chapter 3, we present the study of PL upconversion from a free standing GaN and the mechanism has been attributed to phonon-assisted anti-Stokes photoluminescence (ASPL) if photon energy of pump laser is in the tail of absorption edge. The potential of laser cooling based on such phenomena has been explored. In Chapter 4, we have present detailed PL studies on different kind of nitrides materials including InGaN/GaN QWs, GaN/AlN QWs, GaN thin film and BN powders. In Chapter 5, we explore the possibility of nonlinear generation on GaN. A GaN/AlGaN multilayer waveguide has been designed to achieve transverse parametric conversion. The objective of this dissertation is

  15. Pueblo of Laguna Utility Authority Renewable Energy Feasibility Study

    SciTech Connect

    Carolyn Stewart, Red Mountain Tribal Energy

    2008-03-31

    The project, “Renewable Energy Feasibility Study” was designed to expand upon previous work done by the Tribe in evaluating utility formation, generation development opportunities, examining options for creating self-sufficiency in energy matters, and integrating energy management with the Tribe’s economic development goals. The evaluation of project locations and economic analysis, led to a focus primarily on solar projects.

  16. Optical stimulation enables paced electrophysiological studies in embryonic hearts

    PubMed Central

    Wang, Yves T.; Gu, Shi; Ma, Pei; Watanabe, Michiko; Rollins, Andrew M.; Jenkins, Michael W.

    2014-01-01

    Cardiac electrophysiology plays a critical role in the development and function of the heart. Studies of early embryonic electrical activity have lacked a viable point stimulation technique to pace in vitro samples. Here, optical pacing by high-precision infrared stimulation is used to pace excised embryonic hearts, allowing electrophysiological parameters to be quantified during pacing at varying rates with optical mapping. Combined optical pacing and optical mapping enables electrophysiological studies in embryos under more physiological conditions and at varying heart rates, allowing detection of abnormal conduction and comparisons between normal and pathological electrical activity during development in various models. PMID:24761284

  17. Research and development optical deep space antenna sizing study

    NASA Technical Reports Server (NTRS)

    Wonica, D.

    1994-01-01

    Results from this study provide a basis for the selection of an aperture size appropriate for a research and development ground-based receiver for deep space optical communications. Currently achievable or near-term realizable hardware performance capabilities for both a spacecraft optical terminal and a ground terminal were used as input parameters to the analysis. Links were analyzed using OPTI, our optical link analysis program. Near-term planned and current missions were surveyed and categorized by data rate and telecommunications-subsystems prime power consumption. The spacecraft optical-terminal transmitter power was selected by matching these (RF) data rates and prime power requirements and by applying power efficiencies suitable to an optical communications subsystem. The study was baselined on a Mars mission. Results are displayed as required ground aperture size for given spacecraft transmitter aperture size, parametrized by data rate, transmit optical power, and wavelength.

  18. Optical monitoring of spinal cord hemodynamics, a feasibility study

    NASA Astrophysics Data System (ADS)

    Shadgan, Babak; Kwon, Brian K.; Streijger, Femke; Manouchehri, Neda; So, Kitty; Shortt, Katelyn; Cripton, Peter A.; Macnab, Andrew

    2017-02-01

    Background: After an acute traumatic spinal cord injury (SCI), the spinal cord is subjected to ischemia, hypoxia, and increased hydrostatic pressure which exacerbate further secondary damage and neuronal deficit. The purpose of this pilot study was to explore the use of near infrared spectroscopy (NIRS) for non-invasive and real-time monitoring of these changes within the injured spinal cord in an animal model. NIRS is a non-invasive optical technique that utilizes light in the near infrared spectrum to monitor changes in the concentration of tissue chromophores from which alterations in tissues oxygenation and perfusion can be inferred in real time. Methods: A custom-made miniaturized NIRS sensor was developed to monitor spinal cord hemodynamics and oxygenation noninvasively and in real time simultaneously with invasive, intraparenchymal monitoring in a pig model of SCI. The spinal cord around the T10 injury site was instrumented with intraparenchymal probes inserted directly into the spinal cord to measure oxygen pressure, blood flow, and hydrostatic pressure, and the same region of the spinal cord was monitored with the custom-designed extradural NIRS probe. We investigated how well the extradural NIRS probe detected intraparenchymal changes adjacent to the injury site after alterations in systemic blood pressure, global hypoxia, and traumatic injury generated by a weight-drop contusion. Results: The NIRS sensor successfully identified periods of systemic hypoxia, re-ventilation and changes in spinal cord perfusion and oxygenation during alterations of mean arterial pressure and following spinal cord injury. Conclusion: This pilot study indicates that extradural NIRS monitoring of the spinal cord is feasible as a non-invasive optical method to identify changes in spinal cord hemodynamics and oxygenation in real time. Further development of this technique would allow clinicians to monitor real-time physiologic changes within the injured spinal cord during the

  19. Optical study of solar tower power plants

    NASA Astrophysics Data System (ADS)

    Eddhibi, F.; Ben Amara, M.; Balghouthi, M.; Guizani, A.

    2015-04-01

    The central receiver technology for electricity generation consists of concentrating solar radiation coming from the solar tracker field into a central receiver surface located on the top of the tower. The heliostat field is constituted of a big number of reflective mirrors; each heliostat tracks the sun individually and reflects the sunlight to a focal point. Therefore, the heliostat should be positioned with high precision in order to minimize optical losses. In the current work, a mathematical model for the analysis of the optical efficiency of solar tower field power plant is proposed. The impact of the different factors which influence the optical efficiency is analyzed. These parameters are mainly, the shading and blocking losses, the cosine effect, the atmospheric attenuation and the spillage losses. A new method for the calculation of blocking and shadowing efficiency is introduced and validated by open literature.

  20. Study of all-optical sampling using a semiconductor optical amplifier

    NASA Astrophysics Data System (ADS)

    Wu, Chen; Wang, Yongjun; Wang, Lina; Wang, Fu

    2017-03-01

    All-optical sampling is an important research content of all-optical signal processing. In recent years, the application of the semiconductor optical amplifier (SOA) in optical sampling has attracted lots of attention because of its small volume and large nonlinear coefficient. We propose an optical sampling model based on nonlinear polarization rotation effect of the SOA. The proposed scheme has the advantages of high sampling speed and small input pump power, and a transfer curve with good linearity was obtained through simulation. To evaluate the performance of sampling, we analyze the linearity and efficiency of sampling pulse considering the impact of pulse width and analog signal frequency. We achieve the sampling of analog signal to high frequency pulse and exchange the positions of probe light and pump light to study another sampling.

  1. Studies in Confocal Scanning Optical Microscopy

    NASA Astrophysics Data System (ADS)

    Corle, Timothy Richard

    Optical microscopes have been used as measurement tools in many areas of science of the past 300 years. Despite their maturity, there is still active research in the field. In particular the development of confocal scanning optical microscopes (CSOMs) in the 1970's has extended the usefulness of optical microscopes by giving them depth imaging capabilities. In a CSOM a defocused image disappears rather than blurring as it does with a standard microscope. The shallow depth of focus allows structures with a height difference smaller than one wavelength to be imaged independently, and thus quantitative measurements of height can be made. The design and construction of two CSOMs is discussed. The first is a mechanically scanned single pinhole microscope. This instrument was developed as a test bed on which to try out ideas relating to phase contrast imaging. The second is a Nipkow disk based real-time confocal scanning optical microscope (RSOM). These two microscopes were used to investigate the transverse and depth resolution of CSOMs. It is demonstrated that although they do not intrinsically have any better transverse resolution than a standard optical microscope, CSOMs produce a visually sharper image with increased contrast. The depth response of the CSOM is also investigated. A vector theory for the depth response is derived and compared with experimental results. It is shown that previously unexplained asymmetries in the sidelobe structure of this response can be accounted for by aberrations in the microscope objective. Phase contrast images can be generated by periodically defocusing the microscope, either mechanically or electro -optically and detecting a signal at the modulation frequency. A new electro-optic phase contrast microscope is described. The microscope is used to quantitatively measure both the height and width of thin film gratings. The depth response and point spread function of this microscope are also derived. It is shown that the sidelobe

  2. Histopathologic studies of ischemic optic neuropathy.

    PubMed Central

    Knox, D L; Kerrison, J B; Green, W R

    2000-01-01

    PURPOSE: To define the histopathologic features of eyes in which a pathologic diagnosis of ischemic optic neuropathy had been made in the years 1951 through 1998. METHODS: The following data were documented: age of patient, race, sex, source of tissue, cause of death, clinical history, interval from loss of vision to death, enucleation, exenteration, and biopsy. The histopathologic criteria for diagnosis of ischemic optic neuropathy were the presence of localized ischemic edema, cavernous degeneration, or an area of atrophy located superior or inferior in the optic nerve. Cases with history of abrupt loss of vision were combined with reports from the literature to construct a time table of histopathologic features and associated conditions. RESULTS: Ischemic optic neuropathy was present in 193 eyes. There were 88 females and 65 males. The average age was 71.6 years. Ischemic edema without (early) and with (later) gitter macrophages was present in 26 (13.5%). Cavernous degeneration was present in 69 nerves (36%). Mucopolysaccharide (MPS) was present in 37 cavernous lesions 1 month or longer after loss of vision. Cavernous lesions were seen in 3 eyes in which peripapillary retinal nerve fiber layer hemorrhage had been observed prior to death. Atrophic lesions, the most common pattern, were observed in 133 optic nerves (66.8%). More than 1 ischemic lesion was seen in 38 optic nerves (19.7%). Bilateral ischemic lesions were seen in 50 (35.2%) of 142 paired eyes. CONCLUSIONS: Ischemic optic nerve lesions are initially acellular and later show macrophage infiltration. Cavernous lesions with MPS are present 4 weeks or longer after vision loss. The location of MPS posteriorly and along the internal margin suggests that MPS is produced at the edges of lesions. Progressive vision loss in ischemic optic neuropathy may be secondary to compression of intact nerve from ischemic edema and cavernous swelling, or a second ischemic lesion. Images FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5

  3. Propeller aircraft interior noise model utilization study and validation

    NASA Technical Reports Server (NTRS)

    Pope, L. D.

    1984-01-01

    Utilization and validation of a computer program designed for aircraft interior noise prediction is considered. The program, entitled PAIN (an acronym for Propeller Aircraft Interior Noise), permits (in theory) predictions of sound levels inside propeller driven aircraft arising from sidewall transmission. The objective of the work reported was to determine the practicality of making predictions for various airplanes and the extent of the program's capabilities. The ultimate purpose was to discern the quality of predictions for tonal levels inside an aircraft occurring at the propeller blade passage frequency and its harmonics. The effort involved three tasks: (1) program validation through comparisons of predictions with scale-model test results; (2) development of utilization schemes for large (full scale) fuselages; and (3) validation through comparisons of predictions with measurements taken in flight tests on a turboprop aircraft. Findings should enable future users of the program to efficiently undertake and correctly interpret predictions.

  4. Comparative study of the performance of analog fiber optic links versus free-space optical links

    NASA Astrophysics Data System (ADS)

    Refai, Hakki H.; Sluss, James J., Jr.; Refai, Hazem H.; Atiquzzaman, Mohammed

    2006-02-01

    Optical fiber offers many advantages over coaxial cable for the transmission of radio frequency (rf) signals in antenna-remoting applications, as well as cellular networks and cable television (CATV) signal distribution networks. Optical fiber shows significantly less loss, can support signals demanding much higher bandwidth, is immune to electromagnetic interference (EMI), and enables considerable size and weight savings when compared to coaxial cable. Free-space optics (FSO) communications is a technology that uses modulated optical beams to transmit information line of sight through the atmosphere. FSO can be deployed faster and cheaper when compared with optical fiber. Recently, FSO has been investigated by the telecommunications industry and research centers to transport digital signals for civilian "last mile" applications and military applications. We demonstrate the successful transport of modulated rf analog signals over an FSO link and compare key performance measures against a fiber optic link configured in an identical manner. Results of measurements of optical power, transmission response, reflection response, group delay that defines phase distortion, carrier-to-noise ratio (CNR), and dynamic range that defines nonlinear distortion are presented. Results from this comparative study indicate that FSO for rf applications is a suitable replacement for fiber optic transmission links over short distances.

  5. Cold-agglutinin hemolytic diseases, a rheo-optical study.

    PubMed

    Plá, Laura Verónica; Stoltz, Jean François; Valverde, Juana R; Riquelme, Bibiana D

    2008-01-01

    The aim of this study was to analyze the strength of red blood cells agglutination, induced by autoantibodies in patients with Cold-Agglutinin Hemolytic Disease (CAHD), and the hemorheological profile (deformability and osmotic fragility) by the utilization of rheo-optical techniques. The strength of the antigen-antibody reaction was approached by the work required to dissociate mechanically red blood cells agglutinates. It is focused on the evaluation of the qualitative adhesiveness of cell approached by the dissociation kinetics carried out in a Couette flow (erythroaggregameter). The analysis was performed by recording the increase of the reflectivity signal as the agglutinates are dissociated by shear into smaller ones. A total of eight patients aged <54 years with recent diagnostic of CAHD detected by positive Direct Anti-globulin Test (DAT) and very low RBC counts at 20 degrees C, were studied. Two parametric values were interesting: the dimensionless energy parameter and the characteristic dissociation time, which showed good correlation with hematological parameters. In conclusion, the dissociation method provides a powerful tool for estimating the qualitative adhesiveness of red blood cells agglutinated by autoantibodies in patients suffering of cold-agglutinin hemolytic disease and it would be very interesting to evaluate the severity of the disease.

  6. Optical design of a dual-channel two-focal-length system by utilizing azimuth property of PAL structure

    NASA Astrophysics Data System (ADS)

    Xu, Chen; Cheng, Dewen; Wang, Yongtian

    2016-10-01

    An approach to design a dual-channel two-focal-length lens based on the panoramic annular lens (PAL) structure is presented in this paper. The method of establishing the second channel to eliminate the blind area has been explored in some documents, and mostly it is achieved by utilizing the front surface of the PAL block. But in this paper, we modified the PAL block and divided it into two channels according to their different azimuth direction. These two channels have different focal lengths. Thus, by rotating the system around its axis, optical step-zoom effect can be obtained. Finally, a dual-channel system with a radial zoom ratio of 3× is designed, of which the wide-angle channel has a field-of-view (FOV) of 60° (radial) ×60° (azimuthal) and the long focal length channel has a FOV of 20° (radial)×20° (azimuthal). These two channels share the same stop surface, relay lens, and the image sensor. And a thin glass plate with diffractive structure is placed before the image plane to further correct aberration and obtain a common back focal length for the two channels. This system may have applications in many fields, such as surveillance, robot vision, and foveal imaging.

  7. Experimental demonstration of novel source-free ONUs in bidirectional RF up-converted optical OFDM-PON utilizing polarization multiplexing.

    PubMed

    Zhang, Chongfu; Chen, Chen; Feng, Yuan; Qiu, Kun

    2012-03-12

    We propose and experimentally demonstrate a novel cost-effective optical orthogonal frequency-division multiplexing-based passive optical network (OFDM-PON) system, wherein all optical network units (ONUs) are source-free not only in the optical domain but also in the electric domain, by utilizing polarization multiplexing (PolMUX) in the downlink transmission. Two pure optical bands with a frequency interval of 10 GHz and downlink up-converted 10 GHz OFDM signal are carried in two orthogonal states of polarization (SOPs), respectively. 10 GHz radio frequency (RF) source can be generated by a heterodyne of two pure optical bands after polarization beam splitting in each ONU, therefore it can be used to down-convert the downlink OFDM signal and up-convert the uplink OFDM signal. In the whole bidirectional up-converted OFDM-PON system, only one single RF source is employed in the optical line terminal (OLT). Experimental results successfully verify the feasibility of our proposed cost-effective optical OFDM-PON system.

  8. Study of Dynamic Characteristics of Aeroelastic Systems Utilizing Randomdec Signatures

    NASA Technical Reports Server (NTRS)

    Chang, C. S.

    1975-01-01

    The feasibility of utilizing the random decrement method in conjunction with a signature analysis procedure to determine the dynamic characteristics of an aeroelastic system for the purpose of on-line prediction of potential on-set of flutter was examined. Digital computer programs were developed to simulate sampled response signals of a two-mode aeroelastic system. Simulated response data were used to test the random decrement method. A special curve-fit approach was developed for analyzing the resulting signatures. A number of numerical 'experiments' were conducted on the combined processes. The method is capable of determining frequency and damping values accurately from randomdec signatures of carefully selected lengths.

  9. A theoretical study of optical contact of vitreous silica

    NASA Technical Reports Server (NTRS)

    Barber, T. D.

    1972-01-01

    Optical contact has been proposed as a method of bonding quartz parts of the Stanford relativity satellite. The theory of the van der Waals force is outlined and applied to the problem of optical contact. The effect of various contaminations is discussed and a program of experimentation for further study of the problem is presented.

  10. OPTICAL FIBRES Experimental and theoretical study of optical losses in straight and bent Bragg fibres

    NASA Astrophysics Data System (ADS)

    Aleshkina, S. S.; Likhachev, M. E.; Uspenskii, Yurii A.; Bubnov, M. M.

    2010-12-01

    The leakage loss in straight and bent Bragg fibres has been studied experimentally and theoretically using five fibres differing in the core diameter, the number of layers in the Bragg mirror and their refractive indices. Simple analytical formulas have been derived within ray-optics theory which describe leakage and bending losses. The optical loss calculated using these formulas agrees well with our experimental data. Analysis of the theoretical and experimental results enables us to assess the effect of parameters of the waveguiding system on the optical loss in straight and bent fibres.

  11. Open Quantum System Studies of Optical Lattices and Nonlinear Optical Cavities: A Comprehensive Development of Atomtronics

    NASA Astrophysics Data System (ADS)

    Pepino, Ronald A.

    2011-12-01

    A generalized open quantum theory that models the transport properties of bosonic systems is derived from first principles. This theory is shown to correctly describe the long-time behavior of a specific class of non-Markovian system-reservoir interactions. Starting with strongly-interacting bosons in optical lattices, we use this theory to construct a novel, one-to-one analogy with electronic systems, components, and devices. Beginning with the concept of a wire, we demonstrate theoretically the ultracold boson analog of a semiconductor diode, a field-effect transistor, and a bipolar junction transistor. In a manner directly analogous to electronics, we show that it is possible to construct combinatorial logic structures from the fundamental electronic-emulating devices just described. In this sense, our proposal for atomtronic devices is a useful starting point for arrangements with more complex functionality. In addition we show that the behavior of the proposed diode should also be possible utilizing a weakly-interacting, coherent bosonic drive. After demonstrating the formal equivalence between systems comprised of bosons in optical lattices and photons in nonlinear cavity networks, we use the formalism to extend the ideas and concepts developed earlier in ultracold boson systems to nonlinear optical systems. We adapt the open quantum system theory to this new physical environment, and demonstrate theoretically how a few-photon optical diode can be realized in a coupled nonlinear cavity system. An analysis of different practical cavity quantum electrodynamics systems is presented and experimentally-viable candidates are evaluated.

  12. Steerable optical tweezers for ultracold atom studies.

    PubMed

    Roberts, K O; McKellar, T; Fekete, J; Rakonjac, A; Deb, A B; Kjærgaard, N

    2014-04-01

    We report on the implementation of an optical tweezer system for controlled transport of ultracold atoms along a narrow, static confinement channel. The tweezer system is based on high-efficiency acousto-optic deflectors and offers two-dimensional control over beam position. This opens up the possibility for tracking the transport channel when shuttling atomic clouds along it, forestalling atom spilling. Multiple clouds can be tracked independently by time-shared tweezer beams addressing individual sites in the channel. The deflectors are controlled using a multichannel direct digital synthesizer, which receives instructions on a submicrosecond time scale from a field-programmable gate array. Using the tweezer system, we demonstrate sequential binary splitting of an ultracold 87Rb cloud into 2(5) clouds.

  13. Studying the Mechanochemistry of Processive Cytoskeletal Motors With an Optical Trap.

    PubMed

    Belyy, V; Yildiz, A

    2017-01-01

    Cytoskeletal motors utilize the energy stored in ATP to generate linear motion along rigid filaments. Because their enzymatic cycles are tightly coupled to the production of force and forward movement, the optical-trapping technique is uniquely suited for studying their mechanochemical cycle. Here, we discuss the practical aspects of optical trapping in connection with single-motor assays and describe three distinct experimental modes (fixed-trap, force feedback, and square wave) that are typically used to investigate the enzymatic and biophysical properties of cytoskeletal motors. The principal outstanding questions in the field involve motor regulation by cargo adaptor proteins and cargo transport by teams of motors, ensuring that the optical trap's ability to apply precise forces and measure nanometer-scale displacements will remain crucial to the study of intracellular motility in the foreseeable future. © 2017 Elsevier Inc. All rights reserved.

  14. Comparative study of two CPV optical concentrators, using a Fresnel lens as primary optical element

    NASA Astrophysics Data System (ADS)

    El Himer, S.; El-Yahyaoui, S.; Mechaqrane, A.; Ahaitouf, A.

    2017-03-01

    In this work, the performances of two optimized reflective secondary optics elements a CPC (Compound Parabolic Concentrator) and a Cone for use in a CPV concentrator system are studied using ray-tracing simulation for the same primary optical element: a Fresnel lens. These optical elements are compared in terms of concentration, acceptance angle, exit angle and output light distribution. Our results show that the power distribution at the end of the concentrator is more uniform in the case of the cone. The optical efficiency is higher when the secondary element is placed at a distance f + \\frac{\\text{R}}{{\\tan \\text{θ }}} with f the focal length; R the input radius of the secondary optical element and θ the acceptance angle of the secondary optical element. Also, we found that the length and the input radius of each optical element decrease when the Fresnel lens diameter increases but the input radius of the CPC stills the larger. Finally, our calculation show that the CPC is longer than the cone while the Fresnel lens diameter is less than 200 mm and beyond this value both the cone and the CPC mostly present the same length.

  15. Optical storage media data integrity studies

    NASA Technical Reports Server (NTRS)

    Podio, Fernando L.

    1994-01-01

    Optical disk-based information systems are being used in private industry and many Federal Government agencies for on-line and long-term storage of large quantities of data. The storage devices that are part of these systems are designed with powerful, but not unlimited, media error correction capacities. The integrity of data stored on optical disks does not only depend on the life expectancy specifications for the medium. Different factors, including handling and storage conditions, may result in an increase of medium errors in size and frequency. Monitoring the potential data degradation is crucial, especially for long term applications. Efforts are being made by the Association for Information and Image Management Technical Committee C21, Storage Devices and Applications, to specify methods for monitoring and reporting to the user medium errors detected by the storage device while writing, reading or verifying the data stored in that medium. The Computer Systems Laboratory (CSL) of the National Institute of Standard and Technology (NIST) has a leadership role in the development of these standard techniques. In addition, CSL is researching other data integrity issues, including the investigation of error-resilient compression algorithms. NIST has conducted care and handling experiments on optical disk media with the objective of identifying possible causes of degradation. NIST work in data integrity and related standards activities is described.

  16. Low vision goggles: optical design studies

    NASA Astrophysics Data System (ADS)

    Levy, Ofer; Apter, Boris; Efron, Uzi

    2006-08-01

    Low Vision (LV) due to Age Related Macular Degeneration (AMD), Glaucoma or Retinitis Pigmentosa (RP) is a growing problem, which will affect more than 15 million people in the U.S alone in 2010. Low Vision Aid Goggles (LVG) have been under development at Ben-Gurion University and the Holon Institute of Technology. The device is based on a unique Image Transceiver Device (ITD), combining both functions of imaging and Display in a single chip. Using the ITD-based goggles, specifically designed for the visually impaired, our aim is to develop a head-mounted device that will allow the capture of the ambient scenery, perform the necessary image enhancement and processing, and re-direct it to the healthy part of the patient's retina. This design methodology will allow the Goggles to be mobile, multi-task and environmental-adaptive. In this paper we present the optical design considerations of the Goggles, including a preliminary performance analysis. Common vision deficiencies of LV patients are usually divided into two main categories: peripheral vision loss (PVL) and central vision loss (CVL), each requiring different Goggles design. A set of design principles had been defined for each category. Four main optical designs are presented and compared according to the design principles. Each of the designs is presented in two main optical configurations: See-through system and Video imaging system. The use of a full-color ITD-Based Goggles is also discussed.

  17. Optical storage media data integrity studies

    NASA Astrophysics Data System (ADS)

    Podio, Fernando L.

    1994-03-01

    Optical disk-based information systems are being used in private industry and many Federal Government agencies for on-line and long-term storage of large quantities of data. The storage devices that are part of these systems are designed with powerful, but not unlimited, media error correction capacities. The integrity of data stored on optical disks does not only depend on the life expectancy specifications for the medium. Different factors, including handling and storage conditions, may result in an increase of medium errors in size and frequency. Monitoring the potential data degradation is crucial, especially for long term applications. Efforts are being made by the Association for Information and Image Management Technical Committee C21, Storage Devices and Applications, to specify methods for monitoring and reporting to the user medium errors detected by the storage device while writing, reading or verifying the data stored in that medium. The Computer Systems Laboratory (CSL) of the National Institute of Standard and Technology (NIST) has a leadership role in the development of these standard techniques. In addition, CSL is researching other data integrity issues, including the investigation of error-resilient compression algorithms. NIST has conducted care and handling experiments on optical disk media with the objective of identifying possible causes of degradation. NIST work in data integrity and related standards activities is described.

  18. Nonlinear optical studies of inorganic nanoparticles-polymer nanocomposite coatings fabricated by electron beam curing

    NASA Astrophysics Data System (ADS)

    Misra, Nilanjal; Rapolu, Mounika; Venugopal Rao, S.; Varshney, Lalit; Kumar, Virendra

    2016-05-01

    The optical nonlinearity of metal nanoparticles in dielectrics is of special interest because of their high polarizability and ultrafast response that can be utilized in potential device applications. In this study nanocomposite thin films containing in situ generated Ag nanoparticles dispersed in an aliphatic urethane acrylate (AUA) matrix were synthesized using electron beam curing technique, in presence of an optimized concentration of diluent Trimethylolpropanetriacrylate (TMPTA). The metal nanocomposite films were characterized using UV-visible spectrophotometry, transmission electron microscope (TEM) and field emission scanning electron microscope (FE-SEM) techniques. Ag nanoparticle impregnated films demonstrated an absorption peak at ∼420 nm whose intensity increased with increase in the Ag concentration. The optical limiting property of the coatings was tested using a nanosecond Nd-YAG laser operated at third harmonic wavelength of 355 nm. For a 25 ns pulse and 10 Hz cycle, Ag-polymer coatings showed good optical limiting property and the threshold fluence for optical limiting was found to be ∼3.8×10-2 J/cm2 while the transmission decreased to 82%. The nonlinear optical coefficients were also determined using the standard Z-scan technique with picosecond (∼2 ps, 1 kHz) and femtosecond (∼150 fs, 100 MHz) pulses. Open aperture Z-scan data clearly suggested two-photon absorption as the dominant nonlinear absorption mechanism. Our detailed studies suggest these composites are potential candidates for optical limiting applications.

  19. Polarimetric study of the optical anisotropy of polymers

    NASA Astrophysics Data System (ADS)

    Sinyavsky, N.; Korneva, I.

    2017-07-01

    This paper presents the results of an optical anisotropy study of a polymer film and the effect of temperature on birefringence. A method using a polariscope for the quantitative determination of the optical path difference is offered. The research findings are useful to students of physical and engineering specialities studying electromagnetic theory and optics. The described experiments and theoretical approaches are based on prominent aspects of modern optics. This work can be used to teach students the methods of polarimetry, the method of measuring optical anisotropy, and the basics of colorimetry. Students will learn a color description system to demonstrate the interference of polarized light, as well as being able to make a comparison between the numerical simulation and experiment of the interference pattern.

  20. Surface properties of hard protective coatings studied by optical techniques

    NASA Astrophysics Data System (ADS)

    Jaglarz, Janusz; Wolska, N.; Mitura, K.; Duraj, R.; Marszalek, K. W.; El Kouari, Y.

    2016-06-01

    The paper describes optical study of SiC, C and NiC layers deposited on Si substrates by double beam ion sputtering (DBIS) method. The following optical methods: ellipsometry, bidirectional reflection distribution function (BRDF) and total integrated scattering (TIS) studies have been applied. The obtained results allowed us to determine the refractive indices, extinction coefficients and the roughness parameters of DBIS films. Also surface profiles of optical constants determined from scanning ellipsometric measurements have been presented. The power spectral density functions (PSD) of surface roughness for studied samples have been determined. The influence of the deposition technology on film topography has been discussed.

  1. A study of the potential impacts of space utilization

    NASA Technical Reports Server (NTRS)

    Cheston, T. S.; Chafer, C. M.; Chafer, S. B.; Webb, D. C.; Stadd, C. A.

    1979-01-01

    Because the demand for comprehensive impact analysis of space technologies will increase with the use of space shuttles, the academic social sciences/humanities community was surveyed in order to determine their interests in space utilization, to develop a list of current and planned courses, and to generate a preliminary matrix of relevant social sciences. The academic scope/focus of a proposed social science space-related journal was identified including the disciplines which should be represented in the editorial board/reviewer system. The time and funding necessary to develop a self-sustaining journal were assessed. Cost income, general organizational structure, marking/distribution and funding sources were analyzed. Recommendations based on the survey are included.

  2. Characterization and subsequent utilization of microbially solubilized coal: Preliminary studies

    SciTech Connect

    Davison, B.H.; Nicklaus, D.M.; Woodward, C.A.; Lewis, S.N.; Faison, B.D.

    1989-01-01

    The solubilization of low-ranked coals by fungi, such as Paecilomyces and Candida, in defined submerged culture systems has been demonstrated. Current efforts focus on the characterization of the aqueous solubilized coal products and the development of technologies for their subsequent utilization. Solubilized coal products have been fractionated, and preliminary characterizations performed. Differences in product composition have been detected with respect to the organism used in culture duration. Prospects for the conversion of the aerobically-solubilized coal into less-oxidized products have been developed which can remain active and viable in the presence of the aqueous coal product or vanillin, a coal model compound. The results suggest that a methanogenic consortium was able to produce methane and carbon dioxide from the product of coal biosolubilization by Paecilomyces as a sole carbon source. Work continues on the development of cultures able to convert the aqueous coal product and its various fractions into methane or fuel alcohols. 17 refs., 8 figs.

  3. Oxygen utilization rate (OUR) underestimates ocean respiration: A model study

    NASA Astrophysics Data System (ADS)

    Koeve, W.; Kähler, P.

    2016-08-01

    We use a simple 1-D model representing an isolated density surface in the ocean and 3-D global ocean biogeochemical models to evaluate the concept of computing the subsurface oceanic oxygen utilization rate (OUR) from the changes of apparent oxygen utilization (AOU) and water age. The distribution of AOU in the ocean is not only the imprint of respiration in the ocean's interior but is strongly influenced by transport processes and eventually loss at the ocean surface. Since AOU and water age are subject to advection and diffusive mixing, it is only when they are affected both in the same way that OUR represents the correct rate of oxygen consumption. This is the case only when advection prevails or with uniform respiration rates, when the proportions of AOU and age are not changed by transport. In experiments with the 1-D tube model, OUR underestimates respiration when maximum respiration rates occur near the outcrops of isopycnals and overestimates when maxima occur far from the outcrops. Given the distribution of respiration in the ocean, i.e., elevated rates near high-latitude outcrops of isopycnals and low rates below the oligotrophic gyres, underestimates are the rule. Integrating these effects globally in three coupled ocean biogeochemical and circulation models, we find that AOU-over-age based calculations underestimate true model respiration by a factor of 3. Most of this difference is observed in the upper 1000 m of the ocean with the discrepancies increasing toward the surface where OUR underestimates respiration by as much as factor of 4.

  4. Study of bidirectional broadband passive optical network (BPON) using EDFA

    NASA Astrophysics Data System (ADS)

    Almalaq, Yasser

    Optical line terminals (OLTs) and number of optical network units (ONUs) are two main parts of passive optical network (PON). OLT is placed at the central office of the service providers, the ONUs are located near to the end subscribers. When compared with point-to-point design, a PON decreases the number of fiber used and central office components required. Broadband PON (BPON), which is one type of PON, can support high-speed voice, data and video services to subscribers' residential homes and small businesses. In this research, by using erbium doped fiber amplifier (EDFA), the performance of bi-directional BPON is experimented and tested for both downstream and upstream traffic directions. Ethernet PON (E-PON) and gigabit PON (G-PON) are the two other kinds of passive optical network besides BPON. The most beneficial factor of using BPON is it's reduced cost. The cost of the maintenance between the central office and the users' side is suitable because of the use of passive components, such as a splitter in the BPON architecture. In this work, a bidirectional BPON has been analyzed for both downstream and upstream cases by using bit error rate analyzer (BER). BER analyzers test three factors that are the maximum Q factor, minimum bit error rate, and eye height. In other words, parameters such as maximum Q factor, minimum bit error rate, and eye height can be analyzed utilized a BER tester. Passive optical components such as a splitter, optical circulator, and filters have been used in modeling and simulations. A 12th edition Optiwave simulator has been used in order to analyze the bidirectional BPON system. The system has been tested under several conditions such as changing the fiber length, extinction ratio, dispersion, and coding technique. When a long optical fiber above 40km was used, an EDFA was used in order to improve the quality of the signal.

  5. Picosecond Optical Studies of Semiconductor Dynamics

    NASA Astrophysics Data System (ADS)

    McLean, Daniel Garth

    An investigation of the recombination dynamics of a photoexcited electron-hole plasma is reported. The experiment performed is a pump-probe type utilizing time -of-flight delay techniques to extract the time dependence of a relaxing plasma. Polarization techniques are utilized to eliminate background reflection. The pulses utilized are 15 psec in width at (lamda) = 630nm and excitation energy densities vary between 1-5mJ/cm('2). The theory describing the reflectivity change due to the presence of the plasma and to lattice temperature changes is derived. The theory for the recombination dynamics includes the process of Auger recombination, bimolecular recombination, and linear recombination. The predictions made by the theory within its limitations are compared to the data obtained. Analysis shows that the dynamics predicted are accurate for part of the energy range available, however, at the high energies the limitations placed on the theory are violated and the dynamics observed no longer agree with the predictions. The result is that investigations at these energy densities must account for the lattice temperature rise and its secondary effects. Also this work points out the necessity of an accurate description of the pump energy absorption dynamics in order to fully explain the initial conditions required for and accurate description of the relaxation process.

  6. The Utilization of the RCT Telescope for Studies of Blazar Continuum Emission during the GLAST Gamma-Ray Mission

    NASA Astrophysics Data System (ADS)

    Mattox, J. R.; Cominsky, L.; Spear, G.; Carinni, M.; Gelderman, R.; McGruder, C. H.; Guinan, E.; Howell, S.; Davis, D. R.; Everett, M.; Walter, D. K.

    2003-05-01

    The RCT Consortium successfully proposed to refurbish and automate the Kitt Peak 1.3-m telescope, and to operate it as the Robotically Controlled Telescope (RCT). Refurbishment is nearing completion, and observations have begun. The capabilities of the RCT for broad-band optical photometry will be described. A program for systematic optical monitoring of blazars with the RCT is planned. We anticipate that an important utilization of the RCT will be in conjunction with multi-wavelength studies of blazar continuum emission during the operation of NASA's Gamma-ray Large Area Space Telescope (GLAST) satellite, now scheduled for launch in 2006. Refurbishment of the RCT has been made possible by NASA grant NAG58762.

  7. Study on the creep properties of distributed optical fiber sensors

    NASA Astrophysics Data System (ADS)

    Song, Shiwei; Yang, Caiqian; Wu, Zhishen; Zhang, Yufeng; Shen, Sheng

    2010-04-01

    In this paper, based on the distributed optical fiber strain sensing technology of pulse-pre-pump Brillouin Optical Time Domain Analysis (PPP-BOTDA), the creep properties of two types of optical fiber sensors, i.e. single mode optical fiber with jacket (Type-A) and optical fiber with UV resin coating (Type-B), were studied at different load (60g~600g) amplitudes. Experimental results show that there exists some creep for both types in initial loading period and tend to level off with time. But for Type-B, the strain variation is 5% of initial strain, and the stabilization time is about 48h, both of which are obviously smaller than those of Type-A. As a result, it is revealed that Type-B is characterized by a smaller creep, suitable for the long-term monitoring of infrastructures.

  8. Optical and spectroscopic studies on tannery wastes as a possible source of organic semiconductors

    NASA Astrophysics Data System (ADS)

    Nashy, El-Shahat H. A.; Al-Ashkar, Emad; Abdel Moez, A.

    2012-02-01

    Tanning industry produces a large quantity of solid wastes which contain hide proteins in the form of protein shavings containing chromium salts. The chromium wastes are the main concern from an environmental stand point of view, because chrome wastes posses a significant disposal problem. The present work is devoted to investigate the possibility of utilizing these wastes as a source of organic semi-conductors as an alternative method instead of the conventional ones. The chemical characterization of these wastes was determined. In addition, the Horizontal Attenuated Total Reflection (HATR) FT-IR spectroscopic analysis and optical parameters were also carried out for chromated samples. The study showed that the chromated samples had suitable absorbance and transmittance in the wavelength range (500-850 nm). Presence of chromium salt in the collagen samples increases the absorbance which improves the optical properties of the studied samples and leads to decrease the optical energy gap. The obtained optical energy gap gives an impression that the environmentally hazardous chrome shavings wastes can be utilized as a possible source of natural organic semiconductors with direct and indirect energy gap. This work opens the door to use some hazardous wastes in the manufacture of electronic devices such as IR-detectors, solar cells and also as solar cell windows.

  9. Optical and spectroscopic studies on tannery wastes as a possible source of organic semiconductors.

    PubMed

    Nashy, El-Shahat H A; Al-Ashkar, Emad; Moez, A Abdel

    2012-02-01

    Tanning industry produces a large quantity of solid wastes which contain hide proteins in the form of protein shavings containing chromium salts. The chromium wastes are the main concern from an environmental stand point of view, because chrome wastes posses a significant disposal problem. The present work is devoted to investigate the possibility of utilizing these wastes as a source of organic semi-conductors as an alternative method instead of the conventional ones. The chemical characterization of these wastes was determined. In addition, the Horizontal Attenuated Total Reflection (HATR) FT-IR spectroscopic analysis and optical parameters were also carried out for chromated samples. The study showed that the chromated samples had suitable absorbance and transmittance in the wavelength range (500-850 nm). Presence of chromium salt in the collagen samples increases the absorbance which improves the optical properties of the studied samples and leads to decrease the optical energy gap. The obtained optical energy gap gives an impression that the environmentally hazardous chrome shavings wastes can be utilized as a possible source of natural organic semiconductors with direct and indirect energy gap. This work opens the door to use some hazardous wastes in the manufacture of electronic devices such as IR-detectors, solar cells and also as solar cell windows.

  10. Surface plasmon resonance based fiber optic pH sensor utilizing Ag/ITO/Al/hydrogel layers.

    PubMed

    Mishra, Satyendra K; Gupta, Banshi D

    2013-05-07

    The fabrication and characterization of a surface plasmon resonance based pH sensor using coatings of silver, ITO (In2O3:SnO2), aluminium and smart hydrogel layers over an unclad core of an optical fiber have been reported. The silver, aluminium and ITO layers were coated using a thermal evaporation technique, while the hydrogel layer was prepared using a dip-coating method. The sensor works on the principle of detecting changes in the refractive index of the hydrogel layer due to its swelling and shrinkage caused by changes in the pH of the fluid surrounding the hydrogel layer. The sensor utilizes a wavelength interrogation technique and operates in a particular window of low and high pH values. Increasing the pH value of the fluid causes swelling of the hydrogel layer, which decreases its refractive index and results in a shift of the resonance wavelength towards blue in the transmitted spectra. The thicknesses of the ITO and aluminium layers have been optimized to achieve the best performance of the sensor. The ITO layer increases the sensitivity while the aluminium layer increases the detection accuracy of the sensor. The proposed sensor possesses maximum sensitivity in comparison to the sensors reported in the literature. A negligible effect of ambient temperature in the range 25 °C to 45 °C on the performance of the sensor has been observed. The additional advantages of the sensor are short response time, low cost, probe miniaturization, probe re-usability and the capability of remote sensing.

  11. Study on the spectrophotometric detection of free fatty acids in palm oil utilizing enzymatic reactions.

    PubMed

    Azeman, Nur Hidayah; Yusof, Nor Azah; Abdullah, Jaafar; Yunus, Robiah; Hamidon, Mohd Nizar; Hajian, Reza

    2015-07-07

    In this paper, a comprehensive study has been made on the detection of free fatty acids (FFAs) in palm oil via an optical technique based on enzymatic aminolysis reactions. FFAs in crude palm oil (CPO) were converted into fatty hydroxamic acids (FHAs) in a biphasic lipid/aqueous medium in the presence of immobilized lipase. The colored compound formed after complexation between FHA and vanadium (V) ion solution was proportional to the FFA content in the CPO samples and was analyzed using a spectrophotometric method. In order to develop a rapid detection system, the parameters involved in the aminolysis process were studied. The utilization of immobilized lipase as catalyst during the aminolysis process offers simplicity in the product isolation and the possibility of conducting the process under extreme reaction conditions. A good agreement was found between the developed method using immobilized Thermomyces lanuginose lipase as catalyst for the aminolysis process and the Malaysian Palm Oil Board (MPOB) standard titration method (R2 = 0.9453).

  12. School Utilization Study: Availability, Use, and Support of Instructional Media. 1982-83 Final Report.

    ERIC Educational Resources Information Center

    Riccobono, John A.

    This summary of the 1982-83 School Utilization Study updates and extends the results of a 1976-77 study of school utilization of instructional television and examines changes in instructional television availability and use patterns between 1977 and 1983. The study reported surveyed 619 school superintendents, 1,350 principals, and 2,700 teachers…

  13. Comparison of continuous air monitor utilization: A case study

    SciTech Connect

    Rodgers, J.C.; Whicker, J.J.; Voss, J.T.

    1997-08-01

    The Chemical Metallurgy Research (CMR) building has been upgrading to different continuous air monitors (CAMs) over the past several years. During the transition, both the newer and older CAMs were positioned in the rooms for field testing and comparison. On December 19, 1996, an accidental release of plutonium aerosol occurred into a laboratory in the CMR building. The event occurred while the room was unoccupied, and no personnel were exposed from this incident. There were two fixed air samplers (FASs) and three CAMs operating in the room at the time the release occurred, including two of the recently installed Canberra Alpha Sentry CAMs and one older Eberline CAM. The apparent cause of the release was a procedure carried out in the basement involving the replacement of the HEPA filter in the ventilation exhaust of a slot-box in the laboratory. For a short period, the ventilation was disconnected from the slot-box in this room, but not from the chemical hood exhaust on the opposite side of the laboratory. Therefore, a condition was created where backflow could occur out of the slot-box and into the room. Eventually all three CAMs in the room alarmed, and the situation was successfully monitored and brought under control by health physics personnel. Data on CAM performance were logged, and Pu activity collected on CAM and FAS filters were measured. A comparison of the new and old continuous air monitoring programs was performed and many interesting lessons on CAM performance and CAM utilization were learned. Overall, this comparison showed the advantages of remote monitoring, timely spectral information, and concentration measurements resolved in time and space.

  14. Object utilization and object usage: a single-case study.

    PubMed

    Osiurak, François; Aubin, Ghislaine; Allain, Philippe; Jarry, Christophe; Richard, Isabelle; Le Gall, Didier

    2008-01-01

    It has been suggested that both conceptual knowledge and the ability to infer function from structure can support object use. By contrast, we propose that object use requires solely the ability to reason about technical ends. Technical ends (e.g., cutting) are not purposes (e.g., eating), but the technical way to achieve them. This perspective suggests that there is no mutual relationship between technical ends and purposes since the same purpose (e.g., writing) can be achieved thanks to distinct technical ends (graving, tracing), and, inversely, the same technical end (e.g., tracing) can achieve different purposes (making up, writing). Thus, conceptual knowledge might determine which technical end is usually associated with a given purpose. To contribute to the discussion, we described the behaviour of a female patient with left temporal lobe lesions and bilateral frontal lobe lesions following a closed-head injury. Conceptual knowledge was impaired. She encountered difficulties in demonstrating the use of objects in isolation (e.g., using a screwdriver without the screw). The presence of a recipient (e.g., using a screwdriver with the screw) improved her performance. The performance was also normal when asked to perform unusual applications of objects to achieve a goal for which the usually applied object was not provided (e.g., screwing a screw with a knife). Consistent with the theoretical framework supported here, her performance profile suggests an intact ability to reason about technical ends (i.e., utilization), in the presence of a defective ability to determine the usual relationship between technical ends and purposes (i.e., usage).

  15. Case Studies in Bringing Behavioral Science into Use. Studies in the Utilization of Behavioral Science, Volume I.

    ERIC Educational Resources Information Center

    Glock, Charles Y.; And Others

    A collection of articles by behavioral scientists and users of behavioral science covering the problem of utilization is presented in this volume. Articles include "Applied Social Research: Some Conditions Affecting Its Utilization" by Charles Y. Glock; "Two Case Studies of Utilization of the Behavioral Sciences" by Ronald Lippitt; "Case Studies…

  16. Side-illuminating LED luminaires with accurate projection in high uniformity and high optical utilization factor for large-area field illumination.

    PubMed

    Lo, Yi-Chien; Cai, Jhih-You; Tasi, Ming-Shiou; Tasi, Zheng-Yu; Sun, Ching-Cherng

    2014-03-10

    A novel light luminaire is proposed and experimentally analyzed, which accurately projects light into a large rectangular area to achieve uniform illumination and a high optical utilization factor at the target. Side-illuminating luminaires for large-scale illuminated area are typically set with an elevated tilt angle to enlarge the illuminated area. However, the light pattern is bent thereby reducing the uniformity and optical utilization factor at the target. In this paper, we propose an efficient and useful approach with a rotationally symmetric projection lens that is trimmed to adjust the bending effect and to form a rectangular illumination light pattern on the ground. The design concept is demonstrated and verified. Several potential applications such as highly uniform illumination with fitting shapes for sport courts are analyzed and discussed.

  17. Utilization of optimal study design for maternal and fetal sheep propofol pharmacokinetics study: a preliminary study.

    PubMed

    Sherwin, Catherine M T; Ngamprasertwong, Pornswan; Sadhasivam, Senthilkumar; Vinks, Alexander A

    2014-02-01

    Multiple blood samples are generally required for measurement of pharmacokinetic (PK) parameters. D-optimal design is a popular and frequently used approach for determination of sampling time points in order to minimize the number of samples, while optimizing the estimation of PK parameters. Optimal design utilizing ADAPT (v5, BSR, University of Southern California, Los Angeles) developed a sparse sampling strategy to determine measurement of propofol in pregnant sheep. Propofal was administered as supplemental anesthetic agent to inhalation anesthesia to mimic anesthesia for open fetal surgery. In our preliminary study, propofol 3 mg/kg was given as a bolus to the ewe, followed by propofol infusion at rate 450 mcg/kg/min for 60 minutes, then decreased to 75 mcg/kg/min for 90 more minutes and then ceased. A three compartment model described the PK parameters with the fetus assumed as the third compartment. Initially, sampling times were chosen from thirteen time points as previously stated in the literature. Using priori propofol PK estimates, the final 9 sample time points were proposed in an optimal design with a change in infusion rate occurring between 65 and 75 minutes and sampling proposed at 5, 15, 25, 65, 75, 100, 110, 150, and 180 minutes. D-optimal design optimized the number and timing of samplings, which led to a reduction of cost and man power in the study protocol while preserving the ability to estimate propofol PK parameters in the maternal and fetal sheep model. Initial evaluation of samples collected from three sheep using the optimal design strategy confirmed the performance of the design in obtaining effective PK parameter estimates.

  18. Utilization of Optimal Study Design for Maternal and Fetal Sheep Propofol Pharmacokinetics Study: A Preliminary Study

    PubMed Central

    Sherwin, Catherine M. T.; Ngamprasertwong, Pornswan; Sadhasivam, Senthilkumar; Vinks, Alexander A.

    2017-01-01

    Multiple blood samples are generally required for measurement of pharmacokinetic (PK) parameters. D-optimal design is a popular and frequently used approach for determination of sampling time points in order to minimize the number of samples, while optimizing the estimation of PK parameters. Optimal design utilizing ADAPT (v5, BSR, University of Southern California, Los Angeles) developed a sparse sampling strategy to determine measurement of propofol in pregnant sheep. Propofal was administered as supplemental anesthetic agent to inhalation anesthesia to mimic anesthesia for open fetal surgery. In our preliminary study, propofol 3 mg/kg was given as a bolus to the ewe, followed by propofol infusion at rate 450 mcg/kg/min for 60 minutes, then decreased to 75 mcg/kg/min for 90 more minutes and then ceased. A three compartment model described the PK parameters with the fetus assumed as the third compartment. Initially, sampling times were chosen from thirteen time points as previously stated in the literature. Using priori propofol PK estimates, the final 9 sample time points were proposed in an optimal design with a change in infusion rate occurring between 65 and 75 minutes and sampling proposed at 5, 15, 25, 65, 75, 100, 110, 150, and 180 minutes. D-optimal design optimized the number and timing of samplings, which led to a reduction of cost and man power in the study protocol while preserving the ability to estimate propofol PK parameters in the maternal and fetal sheep model. Initial evaluation of samples collected from three sheep using the optimal design strategy confirmed the performance of the design in obtaining effective PK parameter estimates. PMID:24219004

  19. Fast, high-resolution 3D dosimetry utilizing a novel optical-CT scanner incorporating tertiary telecentric collimation

    SciTech Connect

    Sakhalkar, H. S.; Oldham, M.

    2008-01-15

    This study introduces a charge coupled device (CCD) area detector based optical-computed tomography (optical-CT) scanner for comprehensive verification of radiation dose distributions recorded in nonscattering radiochromic dosimeters. Defining characteristics include: (i) a very fast scanning time of {approx}5 min to acquire a complete three-dimensional (3D) dataset, (ii) improved image formation through the use of custom telecentric optics, which ensures accurate projection images and minimizes artifacts from scattered and stray-light sources, and (iii) high resolution (potentially 50 {mu}m) isotropic 3D dose readout. The performance of the CCD scanner for 3D dose readout was evaluated by comparison with independent 3D readout from the single laser beam OCTOPUS-scanner for the same PRESAGE dosimeters. The OCTOPUS scanner was considered the 'gold standard' technique in light of prior studies demonstrating its accuracy. Additional comparisons were made against calculated dose distributions from the ECLIPSE treatment-planning system. Dose readout for the following treatments were investigated: (i) a single rectangular beam irradiation to investigate small field and very steep dose gradient dosimetry away from edge effects, (ii) a 2-field open beam parallel-opposed irradiation to investigate dosimetry along steep dose gradients, and (iii) a 7-field intensity modulated radiation therapy (IMRT) irradiation to investigate dosimetry for complex treatment delivery involving modulation of fluence and for dosimetry along moderate dose gradients. Dose profiles, dose-difference plots, and gamma maps were employed to evaluate quantitative estimates of agreement between independently measured and calculated dose distributions. Results indicated that dose readout from the CCD scanner was in agreement with independent gold-standard readout from the OCTOPUS-scanner as well as the calculated ECLIPSE dose distribution for all treatments, except in regions within a few millimeters of

  20. Fast, high-resolution 3D dosimetry utilizing a novel optical-CT scanner incorporating tertiary telecentric collimation

    PubMed Central

    Sakhalkar, H. S.; Oldham, M.

    2008-01-01

    This study introduces a charge coupled device (CCD) area detector based optical-computed tomography (optical-CT) scanner for comprehensive verification of radiation dose distributions recorded in nonscattering radiochromic dosimeters. Defining characteristics include: (i) a very fast scanning time of ~5 min to acquire a complete three-dimensional (3D) dataset, (ii) improved image formation through the use of custom telecentric optics, which ensures accurate projection images and minimizes artifacts from scattered and stray-light sources, and (iii) high resolution (potentially 50 μm) isotropic 3D dose readout. The performance of the CCD scanner for 3D dose readout was evaluated by comparison with independent 3D readout from the single laser beam OCTOPUS™-scanner for the same PRESAGE™ dosimeters. The OCTOPUS™ scanner was considered the “gold standard” technique in light of prior studies demonstrating its accuracy. Additional comparisons were made against calculated dose distributions from the ECLIPSE treatment-planning system. Dose readout for the following treatments were investigated: (i) a single rectangular beam irradiation to investigate small field and very steep dose gradient dosimetry away from edge effects, (ii) a 2-field open beam parallel-opposed irradiation to investigate dosimetry along steep dose gradients, and (iii) a 7-field intensity modulated radiation therapy (IMRT) irradiation to investigate dosimetry for complex treatment delivery involving modulation of fluence and for dosimetry along moderate dose gradients. Dose profiles, dose-difference plots, and gamma maps were employed to evaluate quantitative estimates of agreement between independently measured and calculated dose distributions. Results indicated that dose readout from the CCD scanner was in agreement with independent gold-standard readout from the OCTOPUS™-scanner as well as the calculated ECLIPSE dose distribution for all treatments, except in regions within a few

  1. Fast, high-resolution 3D dosimetry utilizing a novel optical-CT scanner incorporating tertiary telecentric collimation.

    PubMed

    Sakhalkar, H S; Oldham, M

    2008-01-01

    This study introduces a charge coupled device (CCD) area detector based optical-computed tomography (optical-CT) scanner for comprehensive verification of radiation dose distributions recorded in nonscattering radiochromic dosimeters. Defining characteristics include: (i) a very fast scanning time of approximately 5 min to acquire a complete three-dimensional (3D) dataset, (ii) improved image formation through the use of custom telecentric optics, which ensures accurate projection images and minimizes artifacts from scattered and stray-light sources, and (iii) high resolution (potentially 50 microm) isotropic 3D dose readout. The performance of the CCD scanner for 3D dose readout was evaluated by comparison with independent 3D readout from the single laser beam OCTOPUS-scanner for the same PRESAGE dosimeters. The OCTOPUS scanner was considered the "gold standard" technique in light of prior studies demonstrating its accuracy. Additional comparisons were made against calculated dose distributions from the ECLIPSE treatment-planning system. Dose readout for the following treatments were investigated: (i) a single rectangular beam irradiation to investigate small field and very steep dose gradient dosimetry away from edge effects, (ii) a 2-field open beam parallel-opposed irradiation to investigate dosimetry along steep dose gradients, and (iii) a 7-field intensity modulated radiation therapy (IMRT) irradiation to investigate dosimetry for complex treatment delivery involving modulation of fluence and for dosimetry along moderate dose gradients. Dose profiles, dose-difference plots, and gamma maps were employed to evaluate quantitative estimates of agreement between independently measured and calculated dose distributions. Results indicated that dose readout from the CCD scanner was in agreement with independent gold-standard readout from the OCTOPUS-scanner as well as the calculated ECLIPSE dose distribution for all treatments, except in regions within a few

  2. L-band all-optical gain-clamped EDFA by utilizing C-band backward ASE

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Jin, Yanli; Dou, Qingying; Liu, Yange; Yuan, Shuzhong; Dong, Xiaoyi

    2006-04-01

    By using an optical circulator and C/L-band wavelength division multiplexer to recycle the C-band backward ASE, an L-band gain-clamped erbium-doped fiber amplifier is presented. We have experimentally studied the static gain clamping property of this amplifier. As the ASE feedback attenuation is set to 0, the gain at 1585 nm can be clamped at 18.84 ± 0.26 dB within dynamic range of 25 dB and the critical power reaches about -15.09 dBm. The gain variation and saturated output power at 1585 nm for 0 dB attenuation are 1 dB lower and 2.17 dB higher than those for 30 dB attenuation, which indicates that the L-band EDFA gain can be effectively clamped via the ASE injection technique.

  3. New insights into the coronary artery bifurcation hypothesis-generating concepts utilizing 3-dimensional optical frequency domain imaging.

    PubMed

    Farooq, Vasim; Serruys, Patrick W; Heo, Jung Ho; Gogas, Bill D; Okamura, Takayuki; Gomez-Lara, Josep; Brugaletta, Salvatore; Garcìa-Garcìa, Hector M; van Geuns, Robert Jan

    2011-08-01

    Coronary artery bifurcations are a common challenging lesion subset accounting for approximately 10% to 20% of all percutaneous coronary interventions. The provisional T-stenting approach is generally recommended as the first-line management of most lesions. Carina shift is suggested to be the predominant mechanism of side-branch pinching during provisional T-stenting and has been indirectly inferred from bench work and other intravascular imaging modalities. Offline 3-dimensional (3D) reconstructions of patients studied in the first-in-man trial of the high-frequency (160 frames/s) Terumo optical frequency domain imaging system were undertaken using volume-rendering software. Through a series of 3D reconstructions, several novel hypothesis-generating concepts are presented.

  4. Design Issues in Qualitative Research: The Case of Knowledge Utilization Studies.

    ERIC Educational Resources Information Center

    Yin, Robert K.; Gwaltney, Margaret K.

    The purpose of this review was to examine research designs in studying knowledge utilization. The results are based on 32 studies of knowledge utilization, and the report describes the various types of research designs and their strengths and weaknesses. Survey research methods are appropriate for dealing with either of two aspects of a…

  5. Structural, optical and nonlinear optical studies of AZO thin film prepared by SILAR method for electro-optic applications

    NASA Astrophysics Data System (ADS)

    Edison, D. Joseph; Nirmala, W.; Kumar, K. Deva Arun; Valanarasu, S.; Ganesh, V.; Shkir, Mohd.; AlFaify, S.

    2017-10-01

    Aluminium doped (i.e. 3 at%) zinc oxide (AZO) thin films were prepared by simple successive ionic layer adsorption and reaction (SILAR) method with different dipping cycles. The structural and surface morphology of AZO thin films were studied by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The optical parameters such as, transmittance, band gap, refractive index, extinction coefficient, dielectric constant and nonlinear optical properties of AZO films were investigated. XRD pattern revealed the formation of hexagonal phase ZnO and the intensity of the film was found to increase with increasing dipping cycle. The crystallite size was found to be in the range of 29-37 nm. Scanning Electron Microscope (SEM) images show the presence of small sized grains, revealing that the smoothest surface was obtained at all the films. The EDAX spectrum of AZO conforms the presence of Zn, O and Al. The optical transmittance in the visible region is high 87% and the band gap value is 3.23 eV. The optical transmittance is decreased with respect to dipping cycles. The room temperature PL studies revealed that the AZO films prepared at (30 cycles) has good film quality with lesser defect density. The third order nonlinear optical parameters were also studied using Z-scan technique to know the applications of deposited films in nonlinear devices. The third order nonlinear susceptibility value is found to be 1.69 × 10-7, 3.34 × 10-8, 1.33 × 10-7and 2.52 × 10-7 for AZO films deposited after 15, 20, 25 and 30 dipping cycles.

  6. Comparative Study of Optical and RF Communication Systems for a Mars Mission - Part II. Unified Value Metrics

    NASA Technical Reports Server (NTRS)

    Hemmati, H.; Layland, J.; Lesh, J.; Wilson, K.; Sue, M.; Rascoe, D.; Lansing, F.; Wilhelm, M.; Harcke, L.; Chen, C.; Feria, Y.

    1997-01-01

    In this Par-II report of the Advanced Communications Benefits study, two critical metrics for comparing the benefits of utilizing X-band, Ka-band and Optical frequencies for supporting generic classes of Martian exploration missions have been evaluated.

  7. Design and analysis study of a spacecraft optical transceiver package

    NASA Technical Reports Server (NTRS)

    Lambert, S. G.

    1985-01-01

    A detailed system level design of an Optical Transceiver Package (OPTRANSPAC) for a deep space vehicle whose mission is outer planet exploration is developed. In addition to the terminal design, this study provides estimates of the dynamic environments to be encountered by the transceiver throughout its mission life. Optical communication link analysis, optical thin lens design, electronic functional design and mechanical layout and packaging are employed in the terminal design. Results of the study describe an Optical Transceiver Package capable of communicating to an Earth Orbiting Relay Station at a distance of 10 Astronomical Units (AU) and data rates up to 100 KBPS. The transceiver is also capable of receiving 1 KBPS of command data from the Earth Relay. The physical dimensions of the terminal are contained within a 3.5' x 1.5' x 2.0' envelope and the transceiver weight and power are estimated at 52.2 Kg (115 pounds) and 57 watts, respectively.

  8. Applied study of optical interconnection link in computer cluster

    NASA Astrophysics Data System (ADS)

    Zhou, Ge; Tian, Jindong; Zhang, Nan; Jing, Wencai; Li, Haifeng

    2000-10-01

    In this paper, some study results to apply fiber link to a computer cluster are presented. The research is based on a ring network topology for a cluster system, which is connected by gigabit/s virtual parallel optical fiber link (VPOFLink) and its driver is for Linux Operating System, the transmission protocol of VPOFLink is compliant with Ethernet standard. We have studied the effect of different types of motherboard on transmission rate of the VPOFLink, and have analyzed the influence of optical interconnection network topology and computer networks protocol on the performance of this optical interconnection computer cluster. The round-trip transmission bandwidth of the VPOFLink have been tested, and the factors that limit transmission bandwidth, such as modes of forwarding data packets in the optical interconnection ring networks, and the size of the link buffer etc., are investigated.

  9. Three-parameter optical studies in Scottish coastal waters

    NASA Astrophysics Data System (ADS)

    McKee, David; Cunningham, Alex; Jones, Ken

    1997-02-01

    A new submersible optical instrument has been constructed which allows chlorophyll fluorescence, attenuation and wide- angle scattering measurements to be made simultaneously at he same point in a body of water. The instrument sues a single xenon flashlamp as the light source, and incorporates its own power supply and microprocessor based data logging system. It has ben cross-calibrated against commercial single-parameter instruments using a range of non-algal particles and phytoplankton cultures. The equipment has been deployed at sea in the Firth of Clyde and Loch Linnhe, where is has been used to study seasonal variability in optical water column structure. Results will be presented to illustrate how ambiguity in the interpretation of measurements of a single optical parameter can be alleviated by measuring several parameters simultaneously. Comparative studies of differences in winter and spring relationships between optical variable shave also ben carried out.

  10. STUDY OF DOSHIC INVOLVEMENT IN APASMARA (EPILEPSY) AND ITS UTILITY

    PubMed Central

    Venkataraghavan, S.; Rajagopalan, V.; Srinivasan, Kanchana

    1987-01-01

    68 cases of epilepsy are studied here for assessing the doshic dominance to understand prognosis with a view to supplement the treatment with some doshahara compounds or drugs. Most of the cases studied or vata or pitta dominant cases, thereby, requiring vatahara or pittahara treatment. PMID:22557563

  11. Study of Optical Properties on Fractal Aggregation Using the GMM Method by Different Cluster Parameters

    NASA Astrophysics Data System (ADS)

    Chang, Kuo-En; Lin, Tang-Huang; Lien, Wei-Hung

    2015-04-01

    Anthropogenic pollutants or smoke from biomass burning contribute significantly to global particle aggregation emissions, yet their aggregate formation and resulting ensemble optical properties are poorly understood and parameterized in climate models. Particle aggregation refers to formation of clusters in a colloidal suspension. In clustering algorithms, many parameters, such as fractal dimension, number of monomers, radius of monomer, and refractive index real part and image part, will alter the geometries and characteristics of the fractal aggregation and change ensemble optical properties further. The cluster-cluster aggregation algorithm (CCA) is used to specify the geometries of soot and haze particles. In addition, the Generalized Multi-particle Mie (GMM) method is utilized to compute the Mie solution from a single particle to the multi particle case. This computer code for the calculation of the scattering by an aggregate of spheres in a fixed orientation and the experimental data have been made publicly available. This study for the model inputs of optical determination of the monomer radius, the number of monomers per cluster, and the fractal dimension is presented. The main aim in this study is to analyze and contrast several parameters of cluster aggregation aforementioned which demonstrate significant differences of optical properties using the GMM method finally. Keywords: optical properties, fractal aggregation, GMM, CCA

  12. Feasibility Study of Optically Transparent Microstrip Patch Antenna

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Lee, Richard Q.

    1997-01-01

    The paper presents a feasibility study on optically transparent patch antennas with microstrip line and probe feeds. The two antennas operate at 2.3 GHz and 19.5 GHz respectively. They are constructed from a thin sheet of clear polyester with an AgHT-8 optically transparent conductive coating. The experimental results show good radiation patterns and input impedance match. The antennas have potential applications in mobile wireless communications.

  13. Feasibility Study of Optically Transparent Microstrip Patch Antenna

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Lee, Richard Q.

    1997-01-01

    The paper presents a feasibility study on optically transparent patch antennas with microstrip line and probe feeds. The two antennas operate at 2.3 GHz and 19.5 GHz respectively. They are constructed from a thin sheet of clear polyester with an AgHT-8 optically transparent conductive coating. The experimental results show good radiation patterns and input impedance match. The antennas have potential applications in mobile wireless communications.

  14. Femtosecond studies of Coulomb explosion utilizing covariance mapping

    NASA Astrophysics Data System (ADS)

    Card, Dennis Alan

    2000-10-01

    The studies presented herein elucidate details of the Coulomb explosion event initiated through the interaction of molecular clusters with an intense femtosecond laser beam (>=1 PW/cm2). Clusters studied include ammonia, titanium-hydrocarbon, pyridine, and 7-azaindole. Covariance analysis is presented as a general technique to study the dynamical processes in clusters and to discern whether the fragmentation channels are competitive. Positive covariance determinations identify concerted processes such as the concomitant explosion of protonated cluster ions of asymmetrical size. Anti- covariance mapping is exploited to distinguish competitive reaction channels such as the production of highly charged nitrogen atoms formed at the expense of the protonated members of a cluster ion ensemble. This technique is exemplified in each cluster system studied. Kinetic energy analyses, from experiment and simulation, are presented to fully understand the Coulomb explosion event. A cutoff study strongly suggests that a Coulomb explosion create ions with two different energies, a direct result of an incomplete Coulomb explosion. A peak analysis implies a strong mass-to-charge dependence on the KER. Taken together, the two studies suggest a duality in the elastic and inelastic contributions to the energy released in a Coulomb explosion. Finally, backward-ejected ions were found capable of arriving before the ion expelled without energy from a Coulomb explosion. Gradient, clustering, and microchannel plate studies confirm the chaotic nature of the Coulomb explosion and the effect clusters have on the event. Backward-ejected protons are found to impact the repeller and eject adsorbed protons from the surface. Moreover, delayed fragmentation is suggested by proton time-of-flights. A cluster study demonstrates the need for clusters at low intensities. Conceptually, the dynamic charge resonance enhanced ionization (CREI) model explains these results of heterocyclic Coulomb explosion

  15. Fiber optic hydrogen gas sensor utilizing surface plasmon resonance and native defects of zinc oxide by palladium

    NASA Astrophysics Data System (ADS)

    Tabassum, Rana; Gupta, Banshi D.

    2016-01-01

    We present an experimental study on a surface plasmon resonance (SPR) based fiber optic hydrogen gas sensor employing a palladium doped zinc oxide nanocomposite (ZnO(1-x)Pd x , 0 ≤ x ≤ 0.85) layer over the silver coated unclad core of the fiber. Palladium doped zinc oxide nanocomposites (ZnO(1-x)Pd x ) are prepared by a chemical route for different composition ratios and their structural, morphological and hydrogen sensing properties are investigated experimentally. The sensing principle involves the absorption of hydrogen gas by ZnO(1-x)Pd x , altering its dielectric function. The change in the dielectric constant is analyzed in terms of the red shift of the resonance wavelength in the visible region of the electromagnetic spectrum. To check the sensing capability of sensing probes fabricated with varying composition ratio (x) of nanocomposite, the SPR curves are recorded typically for 0% H2 and 4% H2 in N2 atmosphere for each fabricated probe. On changing the concentration of hydrogen gas from 0% to 4%, the red shift in the SPR spectrum confirms the change in dielectric constant of ZnO(1-x)Pd x on exposure to hydrogen gas. It is noted that the shift in the SPR spectrum increases monotonically up to a certain fraction of Pd in zinc oxide, beyond which it starts decreasing. SEM images and the photoluminescence (PL) spectra reveal that Pd dopant atoms substitutionally incorporated into the ZnO lattice profoundly affect its defect levels; this is responsible for the optimal composition of ZnO(1-x)Pd x to sense the hydrogen gas. The sensor is highly selective to hydrogen gas and possesses high sensitivity. Since optical fiber sensing technology is employed along with the SPR technique, the present sensor is capable of remote sensing and online monitoring of hydrogen gas.

  16. The utility of genome-wide association studies in hepatology.

    PubMed

    Karlsen, Tom H; Melum, Espen; Franke, Andre

    2010-05-01

    Over the last 4 years, more than 450 genome-wide association studies (GWAS) have been successfully performed in a variety of human traits, of which approximately 2% relates to the field of hepatology. Whereas the many robust susceptibility gene findings have provided insight into fundamental physiological aspects of the phenotypes that have been studied, the widespread application has also revealed important limitations of the GWAS design. This review aims to systematically summarize both the strengths and the weaknesses of GWAS, as well as underscore important experiences made in model diseases outside the field of hepatology. By reviewing the GWAS performed in hepatology so far on this broader background, extensions and guidelines for the rational application of the study design in hepatology are proposed.

  17. A Study of Research Utilization Processes in British Agriculture.

    ERIC Educational Resources Information Center

    Bruce, R.L.

    This study, done in England and Wales, was a first step in developing a model or set of models for describing processes by which agricultural research findings are put into practice. It was decided that the model should be based on actual instances of transmission and use of research. Models by the author and by others were used in developing…

  18. Emergency Department Utilization by Older Adults: a Descriptive Study

    PubMed Central

    Latham, Lesley P.; Ackroyd-Stolarz, Stacy

    2014-01-01

    Background Emergency Departments (EDs) are playing an increasingly important role in the care of older adults. Characterizing ED usage will facilitate the planning for care delivery more suited to the complex health needs of this population. Methods In this retrospective cross-sectional study, administrative and clinical data were extracted from four study sites. Visits for patients aged 65 years or older were characterized using standard descriptive statistics. Results We analyzed 34,454 ED visits by older adults, accounting for 21.8% of the total ED visits for our study time period. Overall, 74.2% of patient visits were triaged as urgent or emergent. Almost half (49.8%) of visits involved diagnostic imaging, 62.1% involved lab work, and 30.8% involved consultation with hospital services. The most common ED diagnoses were symptom- or injury-related (25.0%, 17.1%. respectively). Length of stay increased with age group (Mann-Whitney U; p < .0001), as did the proportion of visits involving diagnostic testing and consultation (χ2; p < .0001). Approximately 20% of older adults in our study population were admitted to hospital following their ED visit. Conclusions Older adults have distinct patterns of ED use. ED resource use intensity increases with age. These patterns may be used to target future interventions involving alternative care for older adults. PMID:25452824

  19. Study of optical design of three-dimensional digital ophthalmoscopes.

    PubMed

    Fang, Yi-Chin; Yen, Chih-Ta; Chu, Chin-Hsien

    2015-10-01

    This study primarily involves using optical zoom structures to design a three-dimensional (3D) human-eye optical sensory system with infrared and visible light. According to experimental data on two-dimensional (2D) and 3D images, human-eye recognition of 3D images is substantially higher (approximately 13.182%) than that of 2D images. Thus, 3D images are more effective than 2D images when they are used at work or in high-recognition devices. In the optical system design, infrared and visible light wavebands were incorporated as light sources to perform simulations. The results can be used to facilitate the design of optical systems suitable for 3D digital ophthalmoscopes.

  20. Optics Studies of the LHC Beam Transfer Line TI8

    SciTech Connect

    J. Wenninger; G. Arduini; B. Goddard; D. Jacquet; V. Kain; M. Lamont; V. Mertens; J.A. Uythoven; Y.-C. Chao

    2005-05-16

    The optics of the newly commissioned LHC beam transfer line TI 8 was studied with beam trajectories, dispersion and profile measurements. Steering magnet response measurements were used to analyze the quality of the steering magnets and of the beam position monitors. A simultaneous fit of the quadrupole strengths was used to search for setting or calibration errors. Residual coupling between the planes was evaluated using high statistics samples of trajectories. Initial conditions for the optics at the entrance of the transfer line were reconstructed from beam profile measurements with Optical Transition Radiation monitors. The paper presents the various analysis methods and their errors. The expected emittance growth arising from optical mismatch into the LHC is evaluated.

  1. A novel Silicon Photomultiplier with bulk integrated quench resistors: utilization in optical detection and tracking applications for particle physics

    NASA Astrophysics Data System (ADS)

    Petrovics, Stefan; Andricek, Ladislav; Diehl, Inge; Hansen, Karsten; Jendrysik, Christian; Krueger, Katja; Lehmann, Raik; Ninkovic, Jelena; Reckleben, Christian; Richter, Rainer; Schaller, Gerhard; Schopper, Florian; Sefkow, Felix

    2017-02-01

    Silicon Photomultipliers (SiPMs) are a promising candidate for replacing conventional photomultiplier tubes (PMTs) in many applications, thanks to ongoing developments and advances in their technology. Conventional SiPMs are generally an array of avalanche photo diodes, operated in Geiger mode and read out in parallel, thus leading to the necessity of a high ohmic quenching resistor. This resistor enables passive quenching and is usually located on top of the array, limiting the fill factor of the device. In this paper, a novel detector concept with a bulk integrated quenching resistor will be recapped. In addition, due to other advantages of this novel detector design, a new concept, in which these devices will be utilized as tracking detectors for particle physics applications will be introduced, as well as first simulation studies and experimental measurements of this new approach.

  2. Methods for measuring utilization of mental health services in two epidemiologic studies

    PubMed Central

    NOVINS, DOUGLAS K.; BEALS, JANETTE; CROY, CALVIN; MANSON, SPERO M.

    2015-01-01

    Objectives of Study Psychiatric epidemiologic studies often include two or more sets of questions regarding service utilization, but the agreement across these different questions and the factors associated with their endorsement have not been examined. The objectives of this study were to describe the agreement of different sets of mental health service utilization questions that were included in the American Indian Service Utilization Psychiatric Epidemiology Risk and Protective Factors Project (AI-SUPERPFP), and compare the results to similar questions included in the baseline National Comorbidity Survey (NCS). Methods Responses to service utilization questions by 2878 AI-SUPERPFP and 5877 NCS participants were examined by calculating estimates of service use and agreement (κ) across the different sets of questions. Logistic regression models were developed to identify factors associated with endorsement of specific sets of questions. Results In both studies, estimates of mental health service utilization varied across the different sets of questions. Agreement across the different question sets was marginal to good (κ = 0.27–0.69). Characteristics of identified service users varied across the question sets. Limitations Neither survey included data to examine the validity of participant responses to service utilization questions. Recommendations for Further Research Question wording and placement appear to impact estimates of service utilization in psychiatric epidemiologic studies. Given the importance of these estimates for policy-making, further research into the validity of survey responses as well as impacts of question wording and context on rates of service utilization is warranted. PMID:18767205

  3. Corrosion and degradation studies utilizing X-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Hixson, Holly Gwyndolen

    1997-08-01

    This dissertation involves studies of corrosion behavior at the surface of various metal samples, as well as the degradation of wool fibers obtained from the Star-Spangled Banner. Molybdenum metal and iron-zinc alloys were examined under corrosive conditions, and the degradation of the wool fibers was studied. The behavior of a polished molybdenum metal surface upon exposure to both aerated and deaerated water and 1.0 M NaCl solution was studied by X-ray Photoelectron Spectroscopy (XPS). Exposure to deaerated water and NaCl failed to produce oxidation of the metal surfaces, but exposing the polished metal surface to aerated water produced significant oxidation. Metal surfaces cleaned by argon-ion etching were found to be inert to oxidation by aerated water. The etching process also appears to passivate the metal surface. The behavior of molybdenum metal in 0.5 M Hsb2SOsb4 treated at various potentials has been studied using core and valence band XPS. The study indicates that Mosp{IV} and Mosp{VI} (including possibly Mosp{V} in some cases) were formed as the potential of the system was increased within the active range of molybdenum. The corrosive behavior of iron-zinc alloys that have been electroplated on plain steel in both aerated and deaerated quadruply-distilled water has been studied using XPS. Several different iron-zinc alloys were electroplated for comparative purposes: an iron-rich alloy, a zinc-rich alloy, and an alloy of similar iron and zinc composition. Treatment in aerated water produces oxidation for the iron-rich and similar composition alloys, but the oxide is reduced for the zinc-rich alloy. Degradation of the fibers in the original Star-Spangled Banner has been monitored using XPS and Scanning Electron Microscopy (SEM). Comparison of white and red wool fibers and linen fibers from the flag with new, mechanically-abraded, and chemically-treated white, red, and linen fibers, respectively, was performed in an attempt to determine the fibers' levels

  4. Comparing Utility Scores in Common Spinal Radiculopathies: Results of a Prospective Valuation Study

    PubMed Central

    Nayak, Nikhil R.; Stephen, James H.; Abdullah, Kalil G.; Stein, Sherman C.; Malhotra, Neil R.

    2015-01-01

    Study Design Prospective observational study. Objective To determine whether preference-based health utility scores for common spinal radiculopathies vary by specific spinal level. Methods We employed a standard gamble study using the general public to calculate individual preference-based quality of life for four common radiculopathies: C6, C7, L5, and S1. We compared utility scores obtained for each level of radiculopathy with analysis of variance and t test. Multivariable regression was used to test the effects of the covariates age, sex, and years of education. We also reviewed the literature for publications reporting EuroQol-5 Dimensions (EQ-5D) scores for patients with radiculopathy. Results Two hundred participants were included in the study. Average utility for the four spinal levels fell within a narrow range (0.748 to 0.796). There were no statistically significant differences between lumbar and cervical radiculopathies, nor were there significant differences among the different spinal levels (F = 0.0850, p = 0.086). Age and sex had no significant effect on utility scores. There was a significant correlation between years of education and utility values for S1 radiculopathy (p = 0.037). On review of the literature, no study separated utility values by specific spinal level. EQ-5D utilities for both cervical and lumbar radiculopathy were considerably lower than the results of our study. Conclusions Utility values associated with the most common levels of cervical and lumbar radiculopathy do not significantly differ from each other, validating the current practice of grouping utility by spinal segment rather than by specific root levels. The discrepancy in average utility values between our study and the EQ-5D highlights the need to be mindful of the underlying instruments used when assessing outcomes studies from different sources. PMID:27099818

  5. Utilization of remote sensing in Alaska permafrost studies

    NASA Technical Reports Server (NTRS)

    Hall, D. K.

    1981-01-01

    Permafrost related features such as: aufeis, tundra, thaw lakes and subsurface ice features were studied. LANDSAT imagery was used to measure the extent and distribution of aufeis in Arctic Slope rivers over a period of 7 years. Interannual extent of large aufeis fields was found to vary significantly. Digital LANDSAT data were used to study the short term effects of a tundra fire which burned a 48 sq km area in northwestern Alaska. Vegetation regrowth was inferred from Landsat spectral reflectance increases and compared to in-situ measurements. Aircraft SAR (Synethic Aperture Radar) imagery was used in conjunction with LANDSAT imagery used in conjunction with LANDSAT imagery to qualitatively determine depth categories for thaw lakes in northern Alaska.

  6. Smarter candidate selection--utilizing microdosing in exploratory clinical studies.

    PubMed

    Buchan, P

    2007-01-01

    Microdosing offers a faster and potentially less expensive approach to obtaining human in vivo PK data in early clinical drug development. It encompasses the use of pharmacologically inactive doses of test drug in the low microgram range along with ultrasensitive assay methods (PET, AMS) to assess human exposure in order to extrapolate the PK of higher, clinically more relevant doses, assuming linear PK. This strategy allows early evaluation of systemic clearance, oral bioavailability as well as sources of intersubject variability and questions of specific metabolite formation. It does take advantage of reduced regulatory requirements of preclinical safety studies, bulk drug synthesis (CMC requirements) and easier formulation options, e.g., as part of an exploratory IND; however, this is counterbalanced by a need to synthesize radiolabeled test compound and the development of a sophisticated analytical method. Ongoing studies will determine the predictability of human PK using Microdosing methods.

  7. The utilization of Computer Mediated Communication for case study collaboration.

    PubMed

    Gwozdek, Anne E; Klausner, Christine P; Kerschbaum, Wendy E

    2008-01-01

    Computer Mediated Communication (CMC) can be used as an effective tool for student communication and collaboration. First-year, first-semester dental hygiene students self-selected groups to develop dental hygiene process of care treatment plans, written reports, and oral case presentations based on assigned clinical cases. In consultation with the University of Michigan (UM) Digital Media Commons Collaborative Technologies Teams, CMC options were identified. Two chat rooms were established within the UM's Course Management System (CTools) to provide opportunities for synchronous (simultaneous, real-time) communication. One course blog site and 8 case blog sites were developed to provide students and instructors with electronic asynchronous (nonsimultaneous) communication formats. The purpose of this study was to evaluate the effectiveness of these technologies during group case study projects. CMC has the potential to provide an effective means of collaboration and communication when the technologies align with the purpose of the project and compliment the dynamics of student groups.

  8. ATHENA: system studies and optics accommodation

    NASA Astrophysics Data System (ADS)

    Ayre, M.; Bavdaz, M.; Ferreira, I.; Wille, E.; Fransen, S.; Stefanescu, A.; Linder, M.

    2016-07-01

    ATHENA is currently in Phase A, with a view to adoption upon a successful Mission Adoption Review in 2019/2020. After a brief presentation of the reference spacecraft (SC) design, this paper will focus on the functional and environmental requirements, the thermo-mechanical design and the Assembly, Integration, Verification & Test (AIVT) considerations related to housing the Silicon Pore Optics (SPO) Mirror Modules (MM) in the very large Mirror Assembly Module (MAM). Initially functional requirements on the MM accommodation are presented, with the Effective Area and Half Energy Width (HEW) requirements leading to a MAM comprising (depending on final mirror size selected) between 700-1000 MMs, co-aligned with exquisite accuracy to provide a common focus. A preliminary HEW budget allocated across the main error-contributors is presented, and this is then used as a reference to derive subsequent requirements and engineering considerations, including: The procedures and technologies for MM-integration into the Mirror Structure (MS) to achieve the required alignment accuracies in a timely manner; stiffness requirements and handling scheme required to constrain deformation under gravity during x-ray testing; temperature control to constrain thermo-elastic deformation during flight; and the role of the Instrument Switching Mechanism (ISM) in constraining HEW and Effective Area errors. Next, we present the key environmental requirements of the MMs, and the need to minimise shock-loading of the MMs is stressed. Methods to achieve this Ø are presented, including: Selection of a large clamp-band launch vehicle interface (LV I/F); lengthening of the shock-path from the LV I/F to the MAM I/F; modal-tuning of the MAM to act as a low-pass filter during launch shock events; use of low-shock HDRMs for the MAM; and the possibility to deploy a passive vibration solution at the LV I/F to reduce loads.

  9. Thermo - optical studies of nematic liquid crystal elastomer

    NASA Astrophysics Data System (ADS)

    Gharde, Rita A.; Mani, Santosh A.; Lal, Suman; Tripathi, S. K.; Khosla, Samriti

    2014-10-01

    The influences of structural parameter on thermo - optical properties of Nematic Liquid Crystal Elastomer (NLCE) were studied using Differential Scanning Calorimetry (DSC), Fourier Transform Infrared (FTIR) Spectroscopy and Polarizing Microscopy Studies (PMS). Dielectric Measurement was also performed in addition to these measurements. The NLCE used in the present study were synthesized, has a unique coupling between anisotropic order of Liquid crystal component and elasticity of polymer network. The investigations were performed as function of temperature during heating and cooling processes. The study revealed the correlation of thermo - optical behavior of NLCE with the crosslinking agent and temperature.

  10. Comparative study of optic disc measurement by Copernicus optical coherence tomography and Heidelberg retinal tomography.

    PubMed

    Yang, Qing-Song; Yu, Ya-Jie; Li, Shu-Ning; Liu, Juan; Hao, Ying-Juan

    2012-08-01

    Copernicus optical coherence tomography (SOCT) is a new, ultra high-speed and high-resolution instrument available for clinical evaluation of optic nerve. The purpose of the study was to compare the agreements between SOCT and Heidelberg retinal tomography (HRT). A total of 44 healthy normal volunteers were recruited in this study. One eye in each subject was selected randomly. Agreement between SOCT and HRT-3 in measuring optic disc area was assessed using Bland-Altman plots. Relationships between measurements of optic nerve head parameter obtained by SOCT and HRT-3 were assessed by Pearson correlation. There was no significant difference in the average cup area (0.306 vs. 0.355 mm, P = 0.766), cup volume (0.158 vs. 0.130 mm, P = 0.106) and cup/disc ration (0.394 vs. 0.349 mm, P = 0.576) measured by the two instruments. However, other optic disc parameters from SOCT were significantly lower compared with HRT-3. The Bland-Altman plot revealed good agreement of cup area and cup volume measured by SOCT and HRT-3. Bad agreement of disc area, rim area, rim volume and cup/disc ratio were found between SOCT and HRT-3. The highest correlations between the two instruments were observed for cup area (r(2) = 0.783, P = 0.000) and cup/disc ratio (r(2) = 0.669, P = 0.000), whereas the lowest correlation was observed for disc area (r(2) = 0.100, P = 0.037), rim area (r(2) = 0.275, P = 0.000), cup volume (r(2) = 0.005, P = 0.391) and rim volume (r(2) = 0.021, P = 0.346). There were poor agreements between SOCT and HRT-3 for measurement of optic nerve parameters except cup area and cup volume. Measurement results of the two instruments are not interchangeable.

  11. Microbiologic Methods Utilized in the MAL-ED Cohort Study

    PubMed Central

    Houpt, Eric; Gratz, Jean; Kosek, Margaret; Zaidi, Anita K. M.; Qureshi, Shahida; Kang, Gagandeep; Babji, Sudhir; Mason, Carl; Bodhidatta, Ladaporn; Samie, Amidou; Bessong, Pascal; Barrett, Leah; Lima, Aldo; Havt, Alexandre; Haque, Rashidul; Mondal, Dinesh; Taniuchi, Mami; Stroup, Suzanne; McGrath, Monica; Lang, Dennis

    2014-01-01

    A central hypothesis of The Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED) study is that enteropathogens contribute to growth faltering. To examine this question, the MAL-ED network of investigators set out to achieve 3 goals: (1) develop harmonized protocols to test for a diverse range of enteropathogens, (2) provide quality-assured and comparable results from 8 global sites, and (3) achieve maximum laboratory throughput and minimum cost. This paper describes the rationale for the microbiologic assays chosen and methodologies used to accomplish the 3 goals. PMID:25305291

  12. A comparative study of ex vivo skin optical clearing using two-photon microscopy.

    PubMed

    Sdobnov, Anton; Darvin, Maxim E; Lademann, Juergen; Tuchin, Valery

    2017-09-01

    Multiphoton tomography (MPT) is a prospective tool for imaging the skin structure. Aiming to increase the probing depth, a comparative ex vivo study of optical clearing of porcine ear skin was performed by using two optical clearing agents (OCAs), i.e., glycerol and iohexol (Omnipaque(TM) ) at different concentrations, which exhibit different osmotic properties. The results show that a topical application of glycerol or Omnipaque(TM) solutions onto the skin for 60 min significantly improved the depth and contrast of the MPT signals. By utilizing 40%, 60% and 100% glycerol, and 60% and 100% Omnipaque(TM) it was demonstrated that both agents improve autofluorescence and SHG (second harmonic generation) signals from the skin. At the applied concentrations and agent time exposure, glycerol is more effective than Omnipaque(TM) . However, tissue shrinkage and cell morphology changes were found for highly concentrated glycerol solutions. Omnipaque(TM) , on the contrary, increases the safety and has no or minimal tissue shrinkage during the optical clearing process. Moreover Omnipaque(TM) allows for robust multimodal optical/X-ray imaging with automatically matched optically cleared and X-ray contrasted tissue volumes. These findings make Omnipaque(TM) more prospective than glycerol for some particular application. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. A study of the optical transmission properties of the polymer HPG

    NASA Astrophysics Data System (ADS)

    Wilkinson, Sonja Renae

    2000-09-01

    Hydroxypropyl Guar (HPG) is a polymer used extensively in the petroleum industry for fracturing oil and gas wells. Understanding the transmission of electromagnetic (EM) radiation in these fluids plays an essential role in the design, development, and improvement of optical sensing devices used to monitor and characterize these polymers. This investigation has resulted in the first comprehensive study of the transmission characteristics of HPG in the visible and near-infrared regions of the electromagnetic spectrum. Optical density data was collected for HPG fluids of various concentrations. Mixtures containing silica flour, a fluid loss additive, were also examined. Based upon optical transmission theory, a method was developed to determine the validity of calculating extinction coefficients at various fluid concentrations throughout the visible and near-infrared region of the spectrum. These coefficients were used to model the depth of penetration of EM radiation into HPG fluids. Calibration methods for optical density and concentration were also evaluated throughout the visible and near-infrared regions. Key results indicate that the best overall penetration into HPG fluids with no silica flour added occurs at wavelengths centered around 865 nm. In the case of fluids containing silica flour, the best penetration occurs at wavelengths centered around 1078 nm. These results, all with many others presented in this dissertation, will be of great utility in the design and development of in situ optical sensors for the characterization of HPG.

  14. Utility of an Equine Clinical Skills Course: A Pilot Study.

    PubMed

    Christensen, Bruce W; Danielson, Jared A

    Recent publications have revealed inadequacies in the veterinary training of future equine practitioners. To help address this problem, a 2-week Equine Clinical Skills course was designed and implemented to provide fourth-year veterinary students with opportunities to have hands-on experience with common equine clinical skills using live animals and cadavers. Alumni and employers of alumni were surveyed to determine whether or not students participating in the course were more competent performing clinical skills during their first year post-graduation than those who had not participated in the course. Students who participated in the course were also surveyed before and after completing the course to determine whether or not their self-assessed skills improved during the course. Alumni who had taken the course rated their ability to perform the clinical skills more highly than alumni who had not taken the course. Similarly, students participating in the course indicated that they were significantly more able to perform the clinical skills after the course than when it began. Employers did not indicate a difference between the clinical skills of those who had taken the course and those who had not. Because this study involved a limited number of respondents from one institution, further studies should be conducted to replicate these findings and determine their generalizability.

  15. A study of the threshold method utilizing raingage data

    NASA Technical Reports Server (NTRS)

    Short, David A.; Wolff, David B.; Rosenfeld, Daniel; Atlas, David

    1993-01-01

    The threshold method for estimation of area-average rain rate relies on determination of the fractional area where rain rate exceeds a preset level of intensity. Previous studies have shown that the optimal threshold level depends on the climatological rain-rate distribution (RRD). It has also been noted, however, that the climatological RRD may be composed of an aggregate of distributions, one for each of several distinctly different synoptic conditions, each having its own optimal threshold. In this study, the impact of RRD variations on the threshold method is shown in an analysis of 1-min rainrate data from a network of tipping-bucket gauges in Darwin, Australia. Data are analyzed for two distinct regimes: the premonsoon environment, having isolated intense thunderstorms, and the active monsoon rains, having organized convective cell clusters that generate large areas of stratiform rain. It is found that a threshold of 10 mm/h results in the same threshold coefficient for both regimes, suggesting an alternative definition of optimal threshold as that which is least sensitive to distribution variations. The observed behavior of the threshold coefficient is well simulated by assumption of lognormal distributions with different scale parameters and same shape parameters.

  16. Case Studies of Water Utility Climate Change Vulnerability Assessment [External Review Draft Report

    EPA Science Inventory

    This report presents a series of case studies describing the approaches taken by four water utilities in the United States to assess their vulnerability to climate change. The report is not intended to be a comprehensive listing of assessment approaches or utilities conducting v...

  17. 75 FR 51806 - Climate Change Vulnerability Assessment: Four Case Studies of Water Utility Practices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-23

    ...-0701] Climate Change Vulnerability Assessment: Four Case Studies of Water Utility Practices AGENCY...-day public comment period for the draft document titled, ``Climate Change Vulnerability Assessment... utilities to assess their vulnerability to future climate change. The report is intended to illustrate the...

  18. Microbiologic methods utilized in the MAL-ED cohort study.

    PubMed

    Houpt, Eric; Gratz, Jean; Kosek, Margaret; Zaidi, Anita K M; Qureshi, Shahida; Kang, Gagandeep; Babji, Sudhir; Mason, Carl; Bodhidatta, Ladaporn; Samie, Amidou; Bessong, Pascal; Barrett, Leah; Lima, Aldo; Havt, Alexandre; Haque, Rashidul; Mondal, Dinesh; Taniuchi, Mami; Stroup, Suzanne; McGrath, Monica; Lang, Dennis

    2014-11-01

    A central hypothesis of The Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED) study is that enteropathogens contribute to growth faltering. To examine this question, the MAL-ED network of investigators set out to achieve 3 goals: (1) develop harmonized protocols to test for a diverse range of enteropathogens, (2) provide quality-assured and comparable results from 8 global sites, and (3) achieve maximum laboratory throughput and minimum cost. This paper describes the rationale for the microbiologic assays chosen and methodologies used to accomplish the 3 goals. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  19. Amino acid utilization by Chlamydomonas reinhardtii: specific study of histidine.

    PubMed

    Hellio, Claire; Veron, Benoit; Le Gal, Yves

    2004-03-01

    Phytoplankton live in fluctuating environments where many factors such as grazing pressure, sinking, light availability, nutrient uptake and turnover influence the distribution of phytoplankton in time and space. The purpose of this study was to investigate if under conditions of depletion of inorganic nitrogen, as recorded in summer in naturals waters, phytoplanktonic species have the capability of using organic nitrogen sources, including free or combined amino acids, in addition to inorganic nitrogen. The study has focussed on histidine, the degradation of which yielding potentially three nitrogen atoms for each molecule of histidine. Chlamydomonas reinhardtii (CCAP 11/32A) was cultivated axenically with two different sources of nitrogen (histidine and/or ammonium). In the presence of histidine as sole source of nitrogen, cell growth was comparable to that observed with the same concentration of nitrogen in ammonium form. In the presence of both histidine and ammonium, histidine degradation was observed only when the concentration of ammonium was depleted. Under these conditions, the first two enzymes of histidine degradation pathway, histidase (EC 4.3.1.3) and urocanase (EC 4.2.1.49) were produced and were co-ordinately regulated. Histidase activity was also controlled by succinate and glutamate as carbon sources. Histidase was purified 1018-fold and partially characterized. The molecular weight of the native enzyme was estimated to 152.4 kDa corresponding to four subunits of 38.1 kDa. The enzyme did not exhibit classical Michaelis-Menten kinetics but showed a relationship between the rate of catalysis (V) and the concentration of substrate (S), characteristic of negative allosteric behavior. A Hill coefficient of 4 was measured for histidine concentrations higher than 20.5 mM.

  20. (Energy related studies utilizing K-feldspar thermochronology)

    SciTech Connect

    Not Available

    1992-01-01

    In our second year of current funding cycle, we have investigated the Ar diffusion properties and microstructures of K-feldspars and the application of domain theory to natural K-feldspars. We completed a combined TEM and argon diffusion study of the effect of laboratory heat treatment on the microstructure and kinetic properties of K-feldspar. We conclude in companion papers that, with one minor exception, no observable change in the diffusion behavior occurs during laboratory extraction procedures until significant fusion occurs at about 1100{degrees}C. The effect that is observed involves a correlation between the homogenization of cryptoperthite lamelle and the apparent increase in retentivity of about 5% of the argon in the K-feldspar under study. We can explain this effect of both as an artifact of the experiment or the loss of a diffusion boundary. Experiments are being considered to resolve this question. Refinements have been made to our experimental protocol that appears that greatly enhance the retrieval of multi-activation energies from K-feldspars. We have applied the multi-domain model to a variety of natural environments (Valles Caldera, Red River fault, Appalachian basin) with some surprising results. Detailed {sup 40}Ar/{sup 39} Ar coverage of the Red River shear zone, thought to be responsible for the accommodation of a significant fraction of the Indo-Asian convergence, strongly suggests that our technique can precisely date both the termination of ductile strike-slip motion and the initiation of normal faulting. Work has continued on improving our numerical codes for calculating thermal histories and the development of computer based graphing tools has significantly increased our productivity.

  1. Utilization of group theory in studies of molecular clusters

    NASA Astrophysics Data System (ADS)

    Ocak, Mahir E.

    The structure of the molecular symmetry group of molecular clusters was analyzed and it is shown that the molecular symmetry group of a molecular cluster can be written as direct products and semidirect products of its subgroups. Symmetry adaptation of basis functions in direct product groups and semidirect product groups was considered in general and the sequential symmetry adaptation procedure which is already known for direct product groups was extended to the case of semidirect product groups. By using the sequential symmetry adaptation procedure a new method for calculating the VRT spectra of molecular clusters which is named as Monomer Basis Representation (MBR) method is developed. In the MBR method, calculations starts with a single monomer with the purpose of obtaining an optimized basis for that monomer as a linear combination of some primitive basis functions. Then, an optimized basis for each identical monomer is generated from the optimized basis of this monomer. By using the optimized bases of the monomers, a basis is generated generated for the solution of the full problem, and the VRT spectra of the cluster is obtained by using this basis. Since an optimized basis is used for each monomer which has a much smaller size than the primitive basis from which the optimized bases are generated, the MBR method leads to an exponential optimization in the size of the basis that is required for the calculations. Application of the MBR method has been illustrated by calculating the VRT spectra of water dimer by using the SAPT-5st potential surface of Groenenboom et al. The rest of the calculations are in good agreement with both the original calculations of Groenenboom et al. and also with the experimental results. Comparing the size of the optimized basis with the size of the primitive basis, it can be said that the method works efficiently. Because of its efficiency, the MBR method can be used for studies of clusters bigger than dimers. Thus, MBR method can

  2. Potential utility of optogenetics in the study of depression

    PubMed Central

    Lobo, Mary Kay; Nestler, Eric J.; Covington, Herbert E.

    2013-01-01

    Novel antidepressants are needed to enhance the health and quality of life of the hundreds-of-millions of depressed individuals worldwide who remain inadequately treated with today’s approaches. In reality, no new class of antidepressant medication has been introduced in over 50 years. This insufficiency of current drug treatments is evident to those eager to pursue invasive experimental options like that of deep brain stimulation (DBS). Encouragingly, human brain imaging studies and animal work implicate strong relationships between depressive symptoms and patterns of brain activity, which are now open to more empirical assessments using optogenetics. Recent advances in optogenetics permit control over specific subtypes of neurons, or their afferent or efferent projections, and can greatly further our understanding of the neural mechanisms involved in depression and the mechanism of action of DBS and perhaps chemical antidepressants. Here, we discuss how optogenetic tools are being used to answer a broad range of molecular, cellular, and circuit-level questions pertaining to depression which, up until now, have been resistant to other experimental approaches. The emergence of optogenetic technology, when combined with the best-validated animal models of depression, will dramatically increase knowledge about the basic neurobiology of depression as well as facilitate the development of more effective antidepressant treatments. PMID:22322104

  3. Utilization of Optical Remote Sensing Data and GIS Tools for Regional Landslide Hazard Analysis Using an Artificial Neural Network Model

    NASA Astrophysics Data System (ADS)

    Biswajeet, Pradhan; Saro, Lee

    The aim of this study is to evaluate landslide hazard analysis at Selangor area, Malaysia using optical remote sensing data and a Geographic Information System (GIS). Landslide locations were identified in the study area from interpretation of aerial photographs and field surveys. Topographical, geological data and satellite images were collected, processed and constructed into a spatial database using GIS and image processing. A total of 10 landslide occurrence factors that were selected including topographic slope, topographic aspect, topographic curvature and distance from drainage; lithology and distance from lineament; land cover from TM satellite images; the vegetation index value from Landsat satellite images; precipitation data. These factors were analyzed using an advanced artificial neural network model to generate the landslide hazard map. Each factor's weight was determined by the back-propagation training method. Then the landslide hazard indices were calculated using the trained back-propagation weights, and finally the landslide hazard map was generated using GIS tools. Landslide locations were used to verify results of the landslide hazard map and the verification results showed 82.92% accuracy. The verification results showed sufficient agreement between the presumptive hazard map and the existing data on landslide areas.

  4. A Preliminary Study of Psychiatric, Familial, and Medical Characteristics of High Utilizing Sickle Cell Disease Patients

    PubMed Central

    Carroll, C. Patrick; Haywood, Carlton; Hoot, Michelle R.; Lanzkron, Sophie

    2012-01-01

    Objectives To identify demographic, medical, and psychosocial characteristics that distinguished sickle cell disease patients who were frequent utilizers of urgent or emergent care resources from low-utilizing patients. Methods Patients at a large urban comprehensive sickle cell disease treatment center were recruited from clinic or during urgent care visits. Participants who were high utilizers, defined as having more than 4 acute or emergency care visits in the prior 12 months, were compared to patients with more typical utilization patterns on lifetime complications of SCD, family background, psychiatric history, occupational function, coping, depressive symptoms, and personality. Results High utilizers were nearly a decade younger on average; despite this they had a similar lifetime history of SCD complications. High utilizing patients' parents appeared to have greater educational achievement overall. High utilizers reported a nearly three-fold greater prevalence of psychiatric illness in family members than low utilizers. On other measures; including coping strategies, social support, and personality; the two groups were comparable. Discussion The study strengthens emerging evidence that disease severity, familial factors related to greater parental education, and psychiatric illness are important factors in high care utilization in patients with sickle cell disease. PMID:23246997

  5. Optical studies of changes in bone mineral density

    NASA Astrophysics Data System (ADS)

    Ugryumova, Nadya; Matcher, Stephen J.; Attenburrow, Don P.

    2003-07-01

    The ability to measure changes in bone-mineral-density (BMD) in-vivo has potential applications in monitoring stress-induced bone remodelling in, for example, competition race horses. In this study we have begun to investigate the potential of optical techniques to monitor such changes via changes in bone optical scattering. Using integrating spheres, we have investigated the optical properties of bone samples taken from the leg of the horse. Since our samples have stable characteristics over the time, we are able to use a single integrating-sphere technique. Diffuse reflection and transmission coefficients have been measured over the wavelength range 520 to 960 nm. Measurements were made on samples immersed in formic acid solution for different lengths of time; this was to investigate the effect of reduction in BMD on the optical properties. The experimental results and a Monte-Carlo based inversion method were used to extract the absorption coefficient and unmodified scattering coefficient of the samples. After full demineralisation scattering coefficient fell by a factor 4. This shows that the calcium-content in bone influences its optical properties considerably. Our experiments confirm the possibility of using optical techniques to determine changes in the BMD of samples.

  6. Performance Study of optical Modulator based on electrooptic effect

    NASA Astrophysics Data System (ADS)

    Palodiya, V.; Raghuwanshi, S. K.

    2016-08-01

    In this paper, we have studied and derive performance parameter of highly integrated Lithium Niobate optical modulator. This is a chirp free modulator having low switching voltage and large bandwidth. For an external modulator in which travelling-wave electrodes length L imposed the modulating switching voltage, the product of Vπ and L is fixed for a given electro optic material Lithium Niobate. We investigate to achieve a low Vπ by both magnitude of the electro-optic coefficient for a wide variety of electro-optic materials. A Sellmeier equation for the extraordinary index of congruent lithium niobate is derived. For phase-matching, predictions are accmate for temperature between room temperature 250°C and wavelength ranging from 0.4 to 5µm. The Sellmeier equations predict more accmately refractive indices at long wavelengths. Theoretical result is confirmed by simulated results. We have analysed the various parameters such as switching voltage, device performance index, time constant, transmittance, cut-off frequency, 3-dB bandwidth, power absorption coefficient and transmission bit rate of Lithium Niobate optical Modulator based on electro -optic effect.

  7. Comparative study of optical fiber cure-monitoring methods

    NASA Astrophysics Data System (ADS)

    Crosby, Peter A.; Powell, Graham R.; Fernando, Gerard F.; Waters, David N.; France, Chris M.; Spooncer, Ronald C.

    1997-06-01

    This paper reports on a comparative study undertaken for different types of optical fiber sensor developed to monitor the cure of an epoxy resin system. The optical fiber sensors used to monitor the cure process were based on transmission spectroscopy, evanescent wave spectroscopy and refractive index monitoring. The transmission sensor was prepared by aligning two optical fibers within a specially prepared sleeve with a gap between the optical fiber end-faces. During cure, resin from the specimen flowed into the gap between the optical fibers allowing transmission spectra of the resin to be obtained. The evanescent wave sensor was prepared by stripping the cladding from a high refractive index core optical fiber. The prepared sensor was embedded in the sample and attenuated total reflectance spectra recorded from the resin/core boundary. Refractive index monitoring was undertaken using a high refractive index core optical fiber which had a small portion of its cladding removed. The prepared sensor was embedded in the resin specimen and light from a single wavelength source was launched into the fiber. Changes in the guiding characteristics of the sensor due to refractive index changes at the resin/core boundary were used to monitor the progress of the cure reaction. The transmission and evanescent wave spectroscopy sensors were used to follow changes in characteristic near-infrared absorption bands of the resin over the range 1450 - 1700 nm during the cure reaction. Consequently these techniques required tunable wavelength sources covering specific wavelength ranges. However, the refractive index based sensor used a single wavelength source. Therefore the equipment costs for this type of sensor were considerably less. Additionally, the refractive index sensor did not require a single wavelength source at any particular wavelength and could be applied to any spectral region in which the optical fiber would transmit light. The advantages and disadvantages of these

  8. Climate@Home: Utilizing Citizen Science for Climate Studies

    NASA Astrophysics Data System (ADS)

    Liu, K.; Yang, C.; Li, Z.; Sun, M.; Li, J.; Xu, C.

    2013-12-01

    Climate change has become a serious and urgent issue in the past decades (Stern N. 2007). It will influence many domains such as agriculture, economy, ecosystem, and others. To help scientists to simulate the climate change, NASA conducted a project, Climate@Home, to develop a cyberinfrastructure for running the modelE climate model. ModelE contains over 500 variables and needs many days to finish a 10 year analysis task. If scientists need to run 300 tasks, it may need about 3 years to complete the task using a single machine. As an exploratory study, an infrastructure was constructed to recruit citizen volunteers for harvesting computing resources from citizens based on the citizen science mechanism. However, there are challenges in order to build the infrastructure: 1) modelE is a Linux based model but volunteers may have different operating system platforms such as Windows, Apple OSX etc (Anderson et al. 2006); 2) modelE has big downloading file and generates big results file, how to download and upload files efficiently? 3) currently the task schedule uses first-come-fist-get mechanism, how to schedule task efficiently? We address these challenges with several designs: 1) virtual machines are used to package the modelE, an operating system and configured running environments; 2) Building FTPS based on users' spatiotemporal information for data downloading and uploading; 3) crafting the schedule system to grant tasks based on the volunteers spatiotemporal information and computing conditions such as CPU, memory and bandwidth. Key words: Volunteer Computing, Climate Change, Spatiotemporal, References: 1. Anderson, D. P., Christensen, C., & Allen, B. (2006, November). Designing a runtime system for volunteer computing. In SC 2006 Conference, Proceedings of the ACM/IEEE (pp. 33-33). IEEE. 2. Stern, N. N. H. (Ed.). (2007). The economics of climate change: the Stern review. Cambridge University Press.

  9. Optical Communications Study for the Next Generation Space Telescope

    NASA Technical Reports Server (NTRS)

    Ceniceros, Juan M.

    2000-01-01

    The Next Generation Space Telescope (NGST), part of NASA's Origins program, is a follow on to the Hubble Space Telescope expected to provide timely new science along with answering fundamental questions. NGST is a large diameter, infrared optimized telescope with imaging and spectrographic detectors which will be used to help study the origin of galaxies. Due to the large data NGST will collect, Goddard Space Flight Center has considered the use of optical communications for data downlink. The Optical Communications Group at the Jet Propulsion Laboratory has performed a study on optical communications systems for NGST. The objective of the study was to evaluate the benefits gained through the use of optical communication technologies. Studies were performed for each of four proposed NGST orbits. The orbits considered were an elliptical orbit about the semi stable second Lagrangian point, a 1 by 3 AU elliptic orbit around the sun, a 1 AU drift orbit, and a 1 AU drift orbit at a 15 degree incline to the ecliptic plane. An appropriate optical communications system was determined for each orbit. Systems were evaluated in terms of mass, power consumption, size, and cost for each of the four proposed orbits.

  10. Nonlinear optical studies of relaxation in semiconductor microstructures

    NASA Astrophysics Data System (ADS)

    Remillard, Jeffrey Thomas

    1990-11-01

    Exposing a semiconductor to optical radiation near the fundamental band gap results in the creation of populations or elementary excitations including electrons, holes, and excitons, and also results in the creation of a superposition state between the ground and excited state of the solid. The relaxation of optically generated excitons and carriers in semiconductor microstructures was studied using four wave mixing (FWM) spectroscopy. The systems studied include CdSSe microcrystallite doped glasses and GaA/AlGaAs multiple quantum well structures (MQWS). First, the nonlinear optical response of simple two level systems is examined in order to provide insight into the types of line shapes expected from semiconductors. It is shown that the line shape is strongly dependent on how the system is coupled to the reservoir and the consequences of coupling to a reservoir are examined in a FWM measurement made in atomic sodium. The first semiconductor system studied is CdSSe microcrystallite doped glass. This system is shown to have a very slow component to the nonlinear response which has an optical intensity dependence and temperature dependence which suggests that the FWM response in these materials is trap mediated. Room temperature FWM measurements in GaAs MQWS enables the measurement of the carrier recombination time and the ambipolar diffusion coefficient. Using the technique of correlated optical fields, a slow component to the nonlinear response was measured showing an interference profile which suggests a possible shift of the exciton resonance due to the optically generated carriers. At low temperatures, measurements of the exciton line shape and relaxation time were made and evidence for exciton spectral diffusion was found. The low temperature line shapes can be qualitatively reproduced using Modified Optical Bloch equations which include the effects of spectral diffusion.

  11. Crystalline perfection, optical and dielectric studies on L-histidine nitrate: A nonlinear optical material

    NASA Astrophysics Data System (ADS)

    Riscob, B.; Kushwaha, S. K.; Shakir, Mohd.; Nagarajan, K.; Maurya, K. K.; Haranath, D.; Roy, S. D. D.; Bhagavannarayana, G.

    2011-12-01

    Single crystals of L-histidine nitrate (LHN), a recently investigated nonlinear optical material, were grown by conventional solution technique. Crystal structure and vibrational modes of the grown crystals were confirmed by powder X-ray diffractometry and FT-Raman spectrometry, respectively. Crystalline perfection of the grown crystals was evaluated by employing an in-house developed high-resolution X-ray diffractometer (HRXRD) and it was found that the grown crystals were free from structural grain boundaries and the perfection was reasonably good. However, HRXRD could reveal the fact that the crystals contain predominantly the interstitial point defects. The birefringence was measured over a range of wavelength between 5480 and 5630 Å and it was found that its value is nearly constant and 10 times higher than that of KDP. The optical band gap was found to be ∼3.73 eV. The photoluminescence excitation and emission spectra for single crystals were recorded. The SHG efficiencies of LHN samples of different particle sizes were measured by the Kurtz and Perry technique and they removed the ambiguity in the values reported differently in the literature. Dielectric properties were studied as a function of temperature over a wide range of frequency. The optical and dielectric studies along with the crystalline perfection reveal that the LHN crystal could be a good candidate for nonlinear optical devices.

  12. An optical study of four regional lakes in upstate New York

    NASA Astrophysics Data System (ADS)

    Kalenak, David S.

    2011-12-01

    The biotic and abiotic factors that determine the optical properties of inland waters include phytoplankton, detrital, and minerogenic suspended particles, and chromophoric dissolved organic matter. Bio-optical models utilize the spectral response (absorption and scattering) of these constituents to identify and estimate mass concentration. This combined with optical remote sensing can significantly enhance real-time monitoring capability. Modern instrumentation has advanced this effort by allowing the measurement of optical properties in situ. However, in situ methods are limited by uncertainties in measurement practices, and analytical models have not been extensively tested in freshwater systems. My research first assesses closure between laboratory and field measurements of the particle absorption coefficient. Difficulty arises in measuring dilute particle suspensions in vivo and concentration methods are necessary. The recommended procedure of filtering particles onto glass-fiber filters subjects the particle substrate to a diffuse light field, creating pathlength amplification that must be corrected for. Using four lakes as test cases, correction estimates were found to be different than previously reported values. Unlike earlier investigations, estimates were shown to be related to particle composition and possibly source (i.e. lake) dependent. Next, I examine semi-analytical algorithms to estimate bulk optical properties through the subsurface remote sensing reflectance ratio. Verified against in situ data, uncertainty in the bidirectional f parameter made closure difficult. Solutions are shown to be very sensitive to the spectral shape of the backscattering coefficient (bbp ). Established algorithms produced erratic outcomes across all four systems, even when bbp was customized to each lake. Transpectral artifacts are also addressed. This study suggests better parameterizations of f and bbp are needed before semi-analytical algorithms can be readily

  13. A Feasibility Study on Generation of Acoustic Waves Utilizing Evanescent Light

    NASA Astrophysics Data System (ADS)

    Matsuya, I.; Matozaki, K.; Kosugi, A.; Ihara, I.

    2014-06-01

    A new approach of generating acoustic waves utilizing evanescent light is presented. The evanescent light is a non-propagating electromagnetic wave that exhibits exponential decay with distance from the surface at which the total internal reflection of light is formed. In this research, the evanescent light during total internal reflection at prism surface is utilized for generating acoustic waves in aluminium and the feasibility for ultrasonic measurements is discussed. Pulsed Nd:YAG laser with 0.36 J/cm2 power density is used and the incident angle during the total internal reflection is arranged to be 69.0° for generating the evanescent light. It has been demonstrated that the amplitude of the acoustic waves by means of evanescent light is about 1/14 as large as the one generated by the conventional pulsed laser. This reveals the possibility of using a laser ultrasonic technique with near-field optics.

  14. Transition in Dental Treatment Utilization in Jammu And Kashmir, India - A 10 Year Retrospective Study

    PubMed Central

    Batra, Manu; Ishrat, A.

    2016-01-01

    Background: Utilization of health services is the actual attendance by the members of the public at health care facilities to receive care. Utilization, serves as an important tool for oral health policy decision-making. The aim of the present study was to retrospectively gauge and assess the utilization pattern of the dental treatments which was given in hospital for last 10 years. Materials and Methods: This retrospective infirmary based study was carried out at Sheri Kashmir Institute of Medical Sciences (SKIMS), Srinagar, Jammu and Kashmir, India. The yearly outpatient department (OPD) records for the utilization of specific dental treatment of a total of 103963 patients were assessed retrospectively from 2014 to 2003. Trend analysis was used to assess the trend of utilization of each speciality with best fitted linear trend lines. Results: The pattern of new patients has also shown a constant rise during the study period except for 2008 and 2009. The utilization of oral surgery speciality has shown a tremendous fall from 2003 to 2014 whereas the number of patients coming to periodontics and conservative dentistry has shown an increasing pattern. Conclusion: Utilization of oral health care has long been used as an indicator of oral health related behaviour of a population. In the present study it can be conclude that the outlook of the population under study has changed from blood and vulcanite dentistry outlook and is moving towards restorative dentistry. . PMID:28804675

  15. NASA's Orbital Debris Optical and IR Ground-based Observing Program: Utilizing the MCAT, UKIRT, and Magellan Telescopes

    NASA Astrophysics Data System (ADS)

    Lederer, S.; Cowardin, H.; Buckalew, B.; Frith, J.; Hickson, P.; Pace, L.; Matney, M.; Anz-Meador, P.; Seitzer, P.; Stansbery, E.; Glesne, T.

    2016-09-01

    Characterizing debris in Earth-orbit has become increasingly important as the growing population of debris poses greater threats to active satellites each year. Currently, the Joint Space Operations is tracking > 23,000 objects ranging in size from 1-meter and larger in Geosychronous orbits (GEO) to 10-cm and larger at low-Earth orbits (LEO). Model estimates suggest that there are hundreds of thousands of pieces of spacecraft debris larger than 10 cm currently in orbit around the Earth. With such a small fraction of the total population being tracked, and new break-ups occurring from LEO to GEO, new assets, techniques, and approaches for characterizing this debris are needed. With this in mind, NASA's Orbital Debris Program Office has actively tasked a suite of telescopes around the world. In 2015, the newly-built 1.3m optical Meter Class Autonomous Telescope (MCAT) came on-line on Ascension Island and is now being commissioned. MCAT is designed to track Earth-orbiting objects above 200km, conduct surveys at GEO, and work with a co-located Raven-class commercial-off-the-shelf system, a 0.4m telescope with a field-of-view similar to MCAT's and research-grade instrumentation designed to complement MCAT. The 3.8m infrared UKIRT telescope on Mauna Kea, Hawaii has been heavily tasked to collect data on individual targets and in survey modes to study both the general GEO population and a break-up event. Data collected include photometry and spectroscopy in the near-Infrared (0.85 - 2.5μm) and the mid-infrared (8-16μm). Finally, the 6.5-m Baade Magellan telescope at Las Campanas Observatory in Chile was used to collect optical photometric survey data in October 2015 of two GEO Titan transtage breakups, focusing on locations of possible debris concentrations as indicated by the NASA standard break-up model.

  16. NASA's Orbital Debris Optical and IR Ground-Based Observing Program Utilizing the MCAT, UKIRT, and Magellan Telescopes

    NASA Technical Reports Server (NTRS)

    Lederer, Susan; Cowardin, H. M.; Buckalew, B.; Frith, J.; Hickson, P.; Pace, L.; Matney, M.; Anz-Meador, P.; Seitzer, P.; Stansbery, E.; hide

    2016-01-01

    Characterizing debris in Earth-orbit has become increasingly important as the population growth rises steadily, posing greater and greater threats to active satellites with each passing year. Currently, the Joint Space Operations is tracking over 23,000 pieces of debris, ranging in size from 1-meter and larger in geosychronous orbits (GEO) to 10-cm and larger at low-Earth orbits (LEO). Model estimates suggest that there may be more than 500,000 pieces of spacecraft debris larger than 1 cm currently in orbit around the Earth. With such a small fraction of the total population being tracked, and new break-ups occurring in LEO, GEO, and Geo Transfer Orbits, new assets, techniques, and approaches for characterizing this debris are needed. With this in mind, NASA's Orbital Debris Program Office has actively tasked a suite of telescopes around the world. In 2015, the newly-built 1.3m optical Meter Class Autonomous Telescope (MCAT) came on-line on Ascension Island in the South Atlantic Ocean and is currently in its commissioning phase. MCAT is designed to track Earth-orbiting objects above 200km, conduct surveys at GEO, and work in tandem with a newly-installed Raven-class commercial-off-the-shelf system, a 0.4-meter telescope co-located on Ascension with a field-of-view similar to MCAT's and research-grade instrumentation designed to complement MCAT for observations taken either simultaneously or in tandem. The 3.8m infrared UKIRT telescope on Mauna Kea, Hawaii, has been heavily tasked throughout 2015 and into 2016, collecting data on individual targets as well as in survey modes to study both the general GEO population as well as an individual break-up event of a BRIZ-M Rocket body that occurred in January 2016. Data collected include photometry and spectroscopy in the near-Infrared (0.85-2.5 m) and the mid-infrared (8-16 m). Finally, the 6.5-m Baade Magellan telescope at Las Campanas Observatory in Chile was used to collect optical photometric survey data in October

  17. Surface plasmon resonance based fiber optic trichloroacetic acid sensor utilizing layer of silver nanoparticles and chitosan doped hydrogel

    NASA Astrophysics Data System (ADS)

    Semwal, Vivek; Shrivastav, Anand M.; Gupta, Banshi D.

    2017-02-01

    In this study, we report a silver nanoparticles/chitosan doped hydrogel-based fiber optic sensor for the detection of trichloroacetic acid (TCA). The sensor is based on the combined phenomenon of localized and propagating surface plasmons. The sensing relies on the interaction of TCA with silver nanoparticles (AgNP) which results in the electron transfer between the negative group of TCA and positive amino group of AgNP stabilizer (chitosan). This alters the mechanical properties/refractive index of the AgNP embedded hydrogel matrix as well as the refractive index of the AgNP. The change in refractive index of both in turn changes the effective refractive index of the nanocomposite hydrogel layer which can be determined using the Maxwell-Garnet Theory. Four stage optimization of the probe fabrication parameters is performed to obtain the best performance of the sensing probe. The sensor operates in the TCA concentration range 0-120 μm which is harmful for the humans and environment. The shift in peak extinction wavelength observed for the same TCA concentration range is 42 nm. The sensor has the linearity range for the TCA concentration range of 40-100 μm. The sensor possesses high sensitivity, selectivity and numerous other advantages such as ease of handling, quick response, modest cost and capability of online monitoring and remote sensing.

  18. Surface plasmon resonance based fiber optic trichloroacetic acid sensor utilizing layer of silver nanoparticles and chitosan doped hydrogel.

    PubMed

    Semwal, Vivek; Shrivastav, Anand M; Gupta, Banshi D

    2017-02-10

    In this study, we report a silver nanoparticles/chitosan doped hydrogel-based fiber optic sensor for the detection of trichloroacetic acid (TCA). The sensor is based on the combined phenomenon of localized and propagating surface plasmons. The sensing relies on the interaction of TCA with silver nanoparticles (AgNP) which results in the electron transfer between the negative group of TCA and positive amino group of AgNP stabilizer (chitosan). This alters the mechanical properties/refractive index of the AgNP embedded hydrogel matrix as well as the refractive index of the AgNP. The change in refractive index of both in turn changes the effective refractive index of the nanocomposite hydrogel layer which can be determined using the Maxwell-Garnet Theory. Four stage optimization of the probe fabrication parameters is performed to obtain the best performance of the sensing probe. The sensor operates in the TCA concentration range 0-120 μm which is harmful for the humans and environment. The shift in peak extinction wavelength observed for the same TCA concentration range is 42 nm. The sensor has the linearity range for the TCA concentration range of 40-100 μm. The sensor possesses high sensitivity, selectivity and numerous other advantages such as ease of handling, quick response, modest cost and capability of online monitoring and remote sensing.

  19. A Feasibility Study on Data Distribution on Optical Media.

    ERIC Educational Resources Information Center

    Campbell (Bonnie) & Associates, Toronto (Ontario).

    This feasibility study assesses the potential of optical technology in the development of accessible bibliographic and location data networks both in Canada and within the international MARC (Machine-Readable Cataloging) network. The study is divided into four parts: (1) a market survey of cataloging and interlibrary loan librarians to determine…

  20. Research Studies on Advanced Optical Module/Head Designs for Optical Data Storage

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Preprints are presented from the recent 1992 Optical Data Storage meeting in San Jose. The papers are divided into the following topical areas: Magneto-optical media (Modeling/design and fabrication/characterization/testing); Optical heads (holographic optical elements); and Optical heads (integrated optics). Some representative titles are as follow: Diffraction analysis and evaluation of several focus and track error detection schemes for magneto-optical disk systems; Proposal for massively parallel data storage system; Transfer function characteristics of super resolving systems; Modeling and measurement of a micro-optic beam deflector; Oxidation processes in magneto-optic and related materials; and A modal analysis of lamellar diffraction gratings in conical mountings.

  1. Optical topographic studies of adults and neonates

    NASA Astrophysics Data System (ADS)

    Nissila, Ilkka T.; Kotilahti, Kalle; Noponen, Tommi E.; Huotilainen, Minna; Naatanen, Risto; Katila, Toivo E.

    2003-07-01

    We used a four-channel intensity-modulated near-infrared spectroscopy device to study the hemodynamic responses due to brain activation in adults and neonates. The stimuli included finger tapping, tickling of the heel, and auditory stimuli. The subjects included two adults and ten neonates of age between 0.5 and 4 days. A block paradigm was used in the studies, and responses were successfully obtained from both subject groups.

  2. Defect studies of optical materials using near-field scanning optical microscopy and spectroscopy

    SciTech Connect

    Yan, M; McWhirter, J; Huser, T; Siekhaus, W

    2001-01-01

    Defects and impurities are generally the key material properties that govern the quality and useful lifetime of optical components. Progress in materials synthesis has advanced so that today, for high power laser applications such as the National Ignition Facility (NIF), laser induced damage is typically initiated at the site of sub-micron defects. For example, in laser glass and non-linear optical crystals such as KDP, bulk damage occurs when sub-micron metal inclusion particles absorb laser energy, leading to local heating and eventually material breakdown. It is clear that continued progress in optical materials synthesis is inextricably connected with the need for a detailed understanding of the morphology and composition of the sub-micron damage nucleation sites and the associated damage mechanisms. In this project, we have developed near-field scanning optical microscopy (NSOM) as a tool to optically characterize materials at a spatial resolution of about one order of magnitude better than conventional optical microscopy. Optical microscopy was the first and thus best understood microscopy, and a large number of contrast and spectroscopy techniques have been developed over the years. NSOM is the logical continuation of optical microscopy to the nanometer scale. NSOM combines scanning probe and optical fiber technologies, and simultaneously provides optical (e.g., spectroscopic properties) and topographic information with typically about 50 nm resolution. This project has resulted in the development of two NSOM instruments, which have been used to perform research on the characterization of surface and sub-surface defects in optical materials developed for NIF projects, including fused silica lenses and windows, KDP crystals and color-separation gratings. This research was directly addressed to laser-induced damage in optical materials, which is initiated by a local variation in optical properties at the sub-micron scale. The work was focused on the detection

  3. First-principles study of optical excitations in alphaquartz

    SciTech Connect

    Chang, Eric K.; Rohlfing, Michael; Louie, Steven G.

    1999-06-15

    The properties of silicon dioxide have been studied extensively over the years. However, there still remain major unanswered questions regarding the nature of the optical spectrum and the role of excitonic effects in this technologically important material. In this work, we present an ab initio study of the optical absorption spectrum of alpha-quartz, using a newly developed first-principles method which includes self-energy and electron-hole interaction effects. The quasiparticle band structure is computed within the GW approximation to obtain a quantitative description of the single-particle excitations. The Bethe-Salpeter equation for the electron-hole excitations is solved to obtain the optical spectrum and to understand the spatial extent and physical properties of the excitons. The theoretical absorption spectrum is found to be in excellent agreement with the measured spectrum. We show that excitonic effects are crucial in the frequency range up to 5 eV above the absorption threshold.

  4. Climate Change Vulnerability Assessments: Four Case Studies of Water Utility Practices (2011 Final)

    EPA Science Inventory

    EPA is releasing the final report titled, Climate Change Vulnerability Assessments: Four Case Studies of Water Utility Practices. This report was prepared by the National Center for Environmental Assessment's Global Climate Research Staff in the Office of Research and Developmen...

  5. Research Studies on Advanced Optical Module/Head Designs for Optical Disk Recording Devices

    NASA Technical Reports Server (NTRS)

    Burke, James J.; Seery, Bernard D.

    1993-01-01

    The Annual Report of the Optical Data Storage Center of the University of Arizona is presented. Summary reports on continuing projects are presented. Research areas include: magneto-optic media, optical heads, and signal processing.

  6. Research studies on advanced optical module/head designs for optical devices

    NASA Technical Reports Server (NTRS)

    Burke, James J.

    1991-01-01

    A summary is presented of research in optical data storage materials and of research at the center. The first section contains summary reports under the general headings of: (1) Magnetooptic media: modeling, design, fabrication, characterization, and testing; (2) Optical heads: holographic optical elements; and (3) Optical heads: integrated optics. The second section consist of a proposal entitled, Signal Processing Techniques for Optical Data Storage. And section three presents various publications prepared by the center.

  7. Horizontal and vertical optic disc rotation. The Beijing Eye Study.

    PubMed

    Fan, Yuan Yuan; Jonas, Jost B; Wang, Ya Xing; Chen, Chang Xi; Wei, Wen Bin

    2017-01-01

    To measure the optic disc rotation around the vertical and horizontal disc axis and to evaluate associations with general and ocular parameters. Population-based study. In the Beijing Eye Study, 3468 participants (mean age:64.6±9.8 years; range:50-93 years) underwent an ophthalmological examination which included spectral-domain optical coherence tomography (OCT) with enhanced depth imaging. Using the OCT images, we determined the amount of the rotation of the optic disc (defined as Bruch´s membrane opening (BMO)) around the vertical axis and horizontal axis. Optic disc rotation measurements were available for 3037 (87.6%) individuals. In multivariate analysis, larger optic disc rotation around the vertical axis (range:-4.90° to 41.0°) was associated (regression coefficient r:0.27) with high axial myopia (axial length ≥26.5 mm) (P<0.001;standardized regression coefficient beta beta:0.09), longer disc-fovea distance (P = 0.001;beta:0.09) and wider parapapillary beta/gamma zone (P<0.001;beta0.12). Larger optic disc rotation around the horizontal axis (range:-7.10° to 26.4°) was associated (r:0.32) with high axial myopia (P = 0.001;beta:0.08), larger optic disc-fovea angle (P<0.001;beta:0.13), thinner superior nasal retinal nerve fiber layer (RNFL) thickness (P<0.001;beta:-0.19) and thicker inferior nasal RNFL thickness (P<0.001;beta:0.17). Vertical optic disc rotation was associated with highly myopic axial elongation, increased disc-fovea distance and development or enlargement of parapapillary, Bruch´s membrane free, gamma zone, while macular Bruch´s membrane length is not affected. Horizontal optic disc rotation was associated with inferior dislocation of the fovea, in addition to a thinner superior nasal RNFL and thicker inferior nasal RNFL. The latter association may be taken into account in the interpretation of RNFL thickness profiles.

  8. Feasibility of utilizing Cherenkov Telescope Array gamma-ray telescopes as free-space optical communication ground stations.

    PubMed

    Carrasco-Casado, Alberto; Vilera, Mariafernanda; Vergaz, Ricardo; Cabrero, Juan Francisco

    2013-04-10

    The signals that will be received on Earth from deep-space probes in future implementations of free-space optical communication will be extremely weak, and new ground stations will have to be developed in order to support these links. This paper addresses the feasibility of using the technology developed in the gamma-ray telescopes that will make up the Cherenkov Telescope Array (CTA) observatory in the implementation of a new kind of ground station. Among the main advantages that these telescopes provide are the much larger apertures needed to overcome the power limitation that ground-based gamma-ray astronomy and optical communication both have. Also, the large number of big telescopes that will be built for CTA will make it possible to reduce costs by economy-scale production, enabling optical communications in the large telescopes that will be needed for future deep-space links.

  9. Electrically switchable polymer liquid crystal and polymer birefringent flake in fluid host systems and optical devices utilizing same

    DOEpatents

    Marshall, Kenneth L.; Kosc, Tanya Z.; Jacobs, Stephen D.; Faris, Sadeg M.; Li, Le

    2003-12-16

    Flakes or platelets of polymer liquid crystals (PLC) or other birefringent polymers (BP) suspended in a fluid host medium constitute a system that can function as the active element in an electrically switchable optical device when the suspension is either contained between a pair of rigid substrates bearing transparent conductive coatings or dispersed as microcapsules within the body of a flexible host polymer. Optical properties of these flake materials include large effective optical path length, different polarization states and high angular sensitivity in their selective reflection or birefringence. The flakes or platelets of these devices need only a 3-20.degree. rotation about the normal to the cell surface to achieve switching characteristics obtainable with prior devices using particle rotation or translation.

  10. The Michigan regulatory incentives study for electric utilities. Phase 1, Final report

    SciTech Connect

    Reid, M.W.; Weaver, E.M.

    1991-06-17

    This is the final report of Phase I of the Michigan Regulatory Incentives Study for Electric Utilities, a three-phase review of Michigan`s regulatory system and its effects on resource selection by electric utilities. The goal of Phase I is to identify and analyze financial incentive mechanisms that encourage selection of resources in accord with the principles of integrated resource planning (IRP) or least-cost planning (LCP). Subsequent study phases will involve further analysis of options and possibly a collaborative formal effort to propose regulatory changes. The Phase I analysis proceeded in three steps: (1) identification and review of existing regulatory practices that affect utilities; selection of resources, particularly DSM; (2) preliminary analysis of ten financial mechanisms, and selection of three for further study; (3) detailed analysis of the three mechanisms, including consideration of how they could be implemented in Michigan and financial modeling of their likely impacts on utilities and ratepayers.

  11. Study of nonlinear magneto-optic effects in BBO

    NASA Astrophysics Data System (ADS)

    Soubusta, Jan; Černoch, Antonín.; Hamrle, Jaroslav; Peřina, Jan; Postava, Kamil

    2016-12-01

    Nonlinear crystals are typically used when interaction of different frequencies of light is requested. In classical optics these nonlinear phenomena are used for second-harmonic generation, sum-frequency generation, optical parametric amplification and many other effects. In quantum optics, dealing with optical interaction on the level of individual photons, the most prominent process is spontaneous parametric down-conversion (SPDC),1 where the crystal is pumped by intensive laser light and the crystal can mediate the splitting of a pump photon to a photon pair. The two generated photons are typically called signal and idler. Influence of magnetic field on these nonlinear processes was not thoroughly tested yet. This topic deserves intensive study both from theoretical and experimental point of view, because the magnetic field can decrease the symmetry of the nonlinear crystal and so it may allow to use new types of phase-matching conditions. We started to test the SPDC process in BBO crystals. Nonlinear magneto-optic tensor of this material is not known and we can hardly predict it. According to our first theoretical derivations the efficiency of the nonlinear processes has to oscillate when rotating the magnetic-field orientation.

  12. Experimental study of optical storage characteristics of photochromic material: pyrrylfulgide

    NASA Astrophysics Data System (ADS)

    Lei, Ming; Yao, Baoli; Chen, Yi; Han, Yong; Wang, Congmin; Wang, Yingli; Menke, Neimule; Chen, Guofu; Fan, Meigong

    2003-04-01

    Optical data storage is a frontier in the information science. Currently, there are mainly two kinds of storage materials, i.e., thermal-optic and photonic materials. The storage methods are divided into serial and parallel modes. In the market, the mature technique is CD-RW, which uses the thermal-optic material and serial method. The storage density of the CD-RW is restricted by the size of material particles, the conduction of heat, etc. Besides, the recording speed is seriously limited by the process of heating. Photonic materials and parallel method will be the trend in the optical data storage. Because it is based on the photon reaction on the molecule scale, the storage density and speed will be greatly increased. In this paper, a new kind of organic photochromic material -- pyrrylfulgide was studied. A parallel optical data storage system was established. Using the pyrrylfulgide/PMMA film as a recording medium, micro-images and binary digital information could be recorded, readout and erased in this parallel system. The recorded information on the film can be kept for at least 8 months in dark at room temperature. So far, the storage density is 3 x 107 bit/cm2.

  13. Statistical Studies of Ground-Based Optical Lightning Signatures

    NASA Astrophysics Data System (ADS)

    Hunt, C. R.; Nemzek, R. J.; Suszcynsky, D. M.

    2005-12-01

    Most extensive optical studies of lightning have been conducted from orbit, and the statistics of events collected from earth are relatively poorly documented. The time signatures of optical power measured in the presence of clouds are inevitably affected by scattering,which can distort the signatures by extending and delaying the amplitude profile in time. We have deployed two all-sky photodiode detectors, one in New Mexico and one in Oklahoma, which are gathering data alongside electric field change monitors as part of the LANL EDOTX Great Plains Array. Preliminary results show that the photodiode is sensitive to approximately 50% or more of RF events detected at ranges of up to 30 km, and still has some sensitivity at ranges in excess of 60 km (distances determined by the EDOTX field-change array). The shapes of events within this range were assessed, with focus on rise time, width, peak power, and their correlation to corresponding electric field signatures, and these are being compared with published on-orbit and ground-based data. Initial findings suggest a mean characteristic width (ratio of total detected optical energy to peak power) of 291 +/- 12 microseconds and a mean delay between the RF signal peak and optical peak of 121 +/- 17 microseconds. These values fall between prior ground-based measurements of direct return stroke emissions, and scattering-dominated on-orbit measurements. This work will promote better understanding of the correspondence between radio and optical measurements of lightning.

  14. Utilization of optical tracking to validate a software-driven isocentric approach to robotic couch movements for proton radiotherapy

    SciTech Connect

    Hsi, Wen C. E-mail: Wenchien.hsi@sphic.org.cn; Zeidan, Omar A.; Law, Aaron; Schreuder, Andreas N.

    2014-08-15

    Purpose: An optical tracking and positioning system (OTPS) was developed to validate the software-driven isocentric (SDI) approach to control the six-degrees-of-freedom movement of a robotic couch. Methods: The SDI approach to movements rotating around a predefined isocenter, referred to as a GeoIso, instead of a mechanical pivot point was developed by the robot automation industry. With robotic couch-sag corrections for weight load in a traditional SDI approach, movements could be accurately executed for a GeoIso located within a 500 mm cubic volume on the couch for treatments. The accuracy of SDI movement was investigated using the OTPS. The GeoIso was assumed to align with the proton beam isocenter (RadIso) for gantry at the reference angle. However, the misalignment between GeoIso and RadIso was quantitatively investigated by measuring the displacements at various couch angles for a target placed at the RadIso at an initial couch angle. When circular target displacements occur on a plane, a relative isocenter shift (RIS) correction could be applied in the SDI movement to minimize target displacements. Target displacements at a fixed gantry angle without and with RIS correction were measured for 12 robotic couches. Target displacements for various gantry angles were performed on three couches in gantry rooms to study the gantry-induced RadIso shift. The RIS correction can also be applied for the RadIso shift. A new SDI approach incorporating the RIS correction with the couch sag is described in this study. In parallel, the accuracy of SDI translation movements for various weight loads of patients on the couch was investigated during positioning of patients for proton prostate treatments. Results: For a fixed gantry angle, measured target displacements without RIS correction for couch rotations in the horizontal plane varied from 4 to 20 mm. However, measured displacements perpendicular to couch rotation plane were about 2 mm for all couches. Extracted

  15. An optically detectable CO2 sensor utilizing polyethylenimine and starch functionalized InGaN/GaN multiple quantum wells

    NASA Astrophysics Data System (ADS)

    Chen, Y. C.; Shih, H. Y.; Chen, J. Y.; Tan, W. J.; Chen, Y. F.

    2013-07-01

    An optically detectable gas sensor based on the high surface sensitivity of functionalized polyethylenimine/starch In0.15Ga0.85N/GaN strained semiconductor multiple quantum wells (MQWs) has been developed. Due to the excellent piezoelectricity of the MQWs, the change of surface charges caused by chemical interaction can introduce a strain and induce an internal field. In turn, it tilts the energy levels of the MQWs and modifies the optical properties. Through the measurement of the changes in photoluminescence as well as Raman scattering spectra under different concentrations of carbon dioxide gas, we demonstrate the feasibility and high sensitivity of the sensors derived from our methodology.

  16. Neutron depth profiling study of lithium niobate optical waveguides

    NASA Astrophysics Data System (ADS)

    Kolářova, P.; Vacík, J.; Špirková-Hradilová, J.; Červená, J.

    1998-05-01

    The relation between optical properties and the structure of proton exchanged and annealed proton exchanged optical waveguides in lithium niobate was studied using the mode spectroscopy and neutron depth profiling methods. We have found a close correlation between the lithium depletion and the depth profile of the extraordinary refractive index. The form of the observed dependence between Li depletion and refractive index depends on the fabrication procedure by which the waveguide was prepared but it is highly reproducible for specimens prepared by the same procedure.

  17. Optical tweezers force measurements to study parasites chemotaxis

    NASA Astrophysics Data System (ADS)

    de Thomaz, A. A.; Pozzo, L. Y.; Fontes, A.; Almeida, D. B.; Stahl, C. V.; Santos-Mallet, J. R.; Gomes, S. A. O.; Feder, D.; Ayres, D. C.; Giorgio, S.; Cesar, C. L.

    2009-07-01

    In this work, we propose a methodology to study microorganisms chemotaxis in real time using an Optical Tweezers system. Optical Tweezers allowed real time measurements of the force vectors, strength and direction, of living parasites under chemical or other kinds of gradients. This seems to be the ideal tool to perform observations of taxis response of cells and microorganisms with high sensitivity to capture instantaneous responses to a given stimulus. Forces involved in the movement of unicellular parasites are very small, in the femto-pico-Newton range, about the same order of magnitude of the forces generated in an Optical Tweezers. We applied this methodology to investigate the Leishmania amazonensis (L. amazonensis) and Trypanossoma cruzi (T. cruzi) under distinct situations.

  18. Peculiarities of RBC aggregation studied by double trap optical tweezers

    NASA Astrophysics Data System (ADS)

    Khokhlova, Maria D.; Lyubin, Evgeny V.; Zhdanov, Alexander G.; Rykova, Sofia Yu.; Krasnova, Tatyana N.; Sokolova, Irina A.; Fedyanin, Andrey A.

    2010-04-01

    Aggregation peculiarities of red blood cells (RBCs) in autologous plasma are studied using double trap optical tweezers technique. The positions of RBCs are controlled with submicrometer accuracy by two optical traps formed by strongly focused laser beams (λ=1064 nm). Quantitative measurements of interaction forces between RBCs in pair aggregates are performed. Depending on the RBCs aggregation force, four different end-points of disaggregation induced by optical trap movement are revealed. Analysis of experimental force dependence on the distance between two RBCs during disaggregation is in a good agreement with the model of ring-shaped interaction surfaces of RBCs in pair aggregate. Aggregation velocities measured are shown to be strongly different for healthy and pathologic (System Lupus Erythematosis - SLE) blood samples.

  19. Numerical simulation studies for optical properties of biomaterials

    NASA Astrophysics Data System (ADS)

    Krasnikov, I.; Seteikin, A.

    2016-11-01

    Biophotonics involves understanding how light interacts with biological matter, from molecules and cells, to tissues and even whole organisms. Light can be used to probe biomolecular events, such as gene expression and protein-protein interaction, with impressively high sensitivity and specificity. The spatial and temporal distribution of biochemical constituents can also be visualized with light and, thus, the corresponding physiological dynamics in living cells, tissues, and organisms in real time. Computer-based Monte Carlo (MC) models of light transport in turbid media take a different approach. In this paper, the optical and structural properties of biomaterials discussed. We explain the numerical simulationmethod used for studying the optical properties of biomaterials. Applications of the Monte-Carlo method in photodynamic therapy, skin tissue optics, and bioimaging described.

  20. Optical studies of high-temperature superconducting cuprates

    NASA Astrophysics Data System (ADS)

    Tajima, Setsuko

    2016-09-01

    The optical studies of high-temperature superconducting cuprates (HTSC) are reviewed. From the doping dependence of room temperature spectra, a dramatic change of the electronic state from a Mott (charge transfer) insulator to a Fermi liquid has been revealed. Additionally, the unusual 2D nature of the electronic state has been found. The temperature dependence of the optical spectra provided a rich source of information on the pseudogap, superconducting gap, Josephson plasmon, transverse Josephson plasma mode and precursory superconductivity. Among these issues, Josephson plasmons and transverse Josephson plasma mode were experimentally discovered by optical measurements, and thus are unique to HTSC. The effect of the spin/charge stripe order is also unique to HTSC, reflecting the conducting nature of the stripe order in this system. The pair-breaking due to the stripe order seems stronger in the out-of-plane direction than in the in-plane one.

  1. Study of optical shuttering action in supramolecular hydrogen bonded nematogens

    NASA Astrophysics Data System (ADS)

    Kavitha, C.; Pongali Sathya Prabu, N.; Madhu Mohan, M. L. N.

    2012-11-01

    Supramolecular hydrogen bonded mesogens are formed between p-n-undecyloxy benzoic acid (11BAO) and p-n-alkyl benzoic acids (nBA, where n = 2-8). The isolated mesogens are characterized by distinct techniques in order to appreciate the optical, thermal, electrical, and dielectric properties. The optical tilt angle measurement is studied for all the members of this homologous series and is found to concur with the mean field theory predicted value. An interesting factor to notice is the observation of optical shuttering action in nematic phase of the entire series which privilege these materials to be used as light modulators. Dielectric measurements were carried out and the dispersion curves were discussed in terms of relaxation frequency and activation energies.

  2. Quasi-Optic Study of Dielectric Radomes and Lenses.

    DTIC Science & Technology

    2014-09-26

    34 , - .- ----" .:i -. * -- ; MICROWAVE RESEARCH INS flT’IE POLY-MPI- 1444-85 AUGUST 1985 " QUASI-OPTIC STUDY OF DIELECTRIC RADOMES AND LENSES In FINAL...New York A Microwave Research Institute N/A Route 110, Farmingdale, New York 11735 II. CONTROLLING OFFICE NAME AND ADDRESS 12. REPORT DATE August 1985

  3. The Zoom Lens: A Case Study in Geometrical Optics.

    ERIC Educational Resources Information Center

    Cheville, Alan; Scepanovic, Misa

    2002-01-01

    Introduces a case study on a motion picture company considering the purchase of a newly developed zoom lens in which students act as the engineers designing the zoom lens based on the criteria of company's specifications. Focuses on geometrical optics. Includes teaching notes and classroom management strategies. (YDS)

  4. Studies of optical ringing in seawater

    NASA Astrophysics Data System (ADS)

    Gilbert, Gary D.; North, Mark H.

    1994-10-01

    A Monte Carlo model is used to examine the effect of water turbidity on the temporal storage of photons. Multiple scattering can store light in increasing scattering orders. It is hypothesized that this light will be present in a LIDAR gate when signal photons return from a distant target and will generally exceed the backscatter predicted by single scatter models. A photon's mean survival time in a turbid medium is the product of the medium's absorption coefficient at the photon's wavelength times the speed of light in the medium. For very clear ocean water this is about 190 nanoseconds. The model considers an unbounded body of water illuminated by light from a pulsed laser beam. An irradiance receiver collocated with the laser transmitter is the detector. Storage is studied as the absorption and scattering constituents of the water are incrementally varied in multiples of those found in clearest sea water. Single scatter albedos ranged from about 0.2 to 0.85 to span naturally occurring conditions. Results for this geometry show multiply scattered light surpassing singly scattered light returns for paths of the order of a volume attenuation length or less.

  5. Leadership skills for the California electric utility industry: A qualitative study

    NASA Astrophysics Data System (ADS)

    Hubbell, Michael

    The purpose of this qualitative study was to determine the skills and knowledge necessary for leaders in the California electric utility industry in 2020. With rapid industry changes, skills to effectively lead and stay competitive are undetermined. Leaders must manage an increasingly hostile social and political environment, incorporate new technology, and deal with an aging workforce and infrastructure. Methodology. This study utilized a qualitative case study design to determine the factors that influence the skills leaders will require in 2020. It incorporated the perspectives of current electric utility leaders while looking with a future lens. Findings. Interviews were conducted with transmission and distribution (T&D) directors at 3 investor-owned public electric utilities headquartered in California. The questions followed an open-ended format to gather responses as perceived by electric utility leaders for each research question category: overall skills, aging workforce, regulation, technology, and leading younger generations. The research resulted in 18 major themes: 5 for overall skills, 3 for aging workforce, 4 for regulation, 3 for technology, and 3 for leading younger generations. Conclusions. The study identified leadership skills including the ability to embrace, leverage, and stay current with technology; understand and provide a clear vision for the future; increase creativity; manage the next set of workers; motivate during a time of great change; prepare for knowledge transfer and change in workforce culture; manage regulatory expectations; expand potential utility opportunities; leverage "big data"; allow worker collaboration; and understand what drives younger generations. Recommendations. California-based electric utility leaders can remain effective by implementing key strategies identified herein. Further research could examine perspectives of additional utility leaders who lead in organizational units outside of T&D, expand the research to

  6. Unique Search and Track Procedures Utilizing the Ground-based Electro-Optical Deep Space Surveillance (GEODSS) Worldwide Sites

    DTIC Science & Technology

    2011-09-01

    to affect the success rate of finding lost objects using the GEODSS Optical Sensors. Figure 1. Vela-5A/B satellites in clean room in...author or source of a work, even if it is in the public domain, is still required to avoid plagiarism . Source: http://heasarc.gsfc.nasa.gov/docs/vela5b

  7. Husbands' involvement in delivery care utilization in rural Bangladesh: A qualitative study

    PubMed Central

    2012-01-01

    Background A primary cause of high maternal mortality in Bangladesh is lack of access to professional delivery care. Examining the role of the family, particularly the husband, during pregnancy and childbirth is important to understanding women's access to and utilization of professional maternal health services that can prevent maternal mortality. This qualitative study examines husbands' involvement during childbirth and professional delivery care utilization in a rural sub-district of Netrokona district, Bangladesh. Methods Using purposive sampling, ten households utilizing a skilled attendant during the birth of the youngest child were selected and matched with ten households utilizing an untrained traditional birth attendant, or dhatri. Households were selected based on a set of inclusion criteria, such as approximate household income, ethnicity, and distance to the nearest hospital. Twenty semi-structured interviews were conducted in Bangla with husbands in these households in June 2010. Interviews were transcribed, translated into English, and analyzed using NVivo 9.0. Results By purposefully selecting households that differed on the type of provider utilized during delivery, common themes--high costs, poor transportation, and long distances to health facilities--were eliminated as sufficient barriers to the utilization of professional delivery care. Divergent themes, namely husbands' social support and perceived social norms, were identified as underlying factors associated with delivery care utilization. We found that husbands whose wives utilized professional delivery care provided emotional, instrumental and informational support to their wives during delivery and believed that medical intervention was necessary. By contrast, husbands whose wives utilized an untrained dhatri at home were uninvolved during delivery and believed childbirth should take place at home according to local traditions. Conclusions This study provides novel evidence about male

  8. Antihypertensive medicines utilization: A decade-long nationwide study of octogenarians, nonagenarians and centenarians.

    PubMed

    Narayan, Sujita W; Nishtala, Prasad S

    2017-07-01

    Gaining an insight into the utilization of antihypertensive medicines against a background of evolving hypertension treatment guidelines that might not be relevant to the oldest old is important. The aim of the present study was to characterize the overall trends in the utilization of antihypertensive medicines in the oldest old by therapeutic class and chemical type, stratified by age and sex over a decade. Antihypertensive medicines utilization was examined using the therapeutic and chemical groups based on the World Health Organization Collaborating Center for Drug Statistics Mythology's Anatomical Therapeutic Chemical classification system for all individuals aged ≥80 years. Regression and repeated cross-sectional analyses was carried out, and defined daily dose was used to describe the utilization per thousand older people per day. Utilization of antihypertensive medicines increased over the decade from 187.28 in 2005 to 205.01 defined daily dose per thousand older people per day in 2014, and shifted from mainly diuretics to angiotensin-converting enzyme inhibitors. Interestingly, with the exception of diuretics, utilization of all medicines decreased gradually with increasing age. Single products use increased by 1.48-fold in 2014 compared with 2005, and for fixed-dose combinations the increase was 1.41-fold for the same period. The increased utilization of angiotensin-converting enzyme inhibitors is consistent with recommendations from cardiovascular guidelines formulated from large randomized control trials that often exclude the oldest old. Interestingly, the utilization of beta-blockers decreased and diuretics increased in centenarians. The utilization of calcium channel blockers and angiotensin-converting enzyme inhibitors across the study period increased in all age categories. Geriatr Gerontol Int 2017; 17: 1109-1117. © 2016 Japan Geriatrics Society.

  9. Assessment of Social Media Utilization and Study Habit of Students of Tertiary Institutions in Katsina State

    ERIC Educational Resources Information Center

    Olutola, Adekunle Thomas; Olatoye, Olufunke Omotoke; Olatoye, Rafiu Ademola

    2016-01-01

    This study investigated assessment of social media utilization and study habits of students of tertiary institutions in Katsina State. The descriptive survey design was adopted for this study. Three hundred and eighty-one (381) students' of tertiary institutions in Katsina State were randomly selected for the study. Researchers'-designed…

  10. Optical manipulation and microfluidics for studies of single cell dynamics

    NASA Astrophysics Data System (ADS)

    Eriksson, E.; Scrimgeour, J.; Granéli, A.; Ramser, K.; Wellander, R.; Enger, J.; Hanstorp, D.; Goksör, M.

    2007-08-01

    Most research on optical manipulation aims towards investigation and development of the system itself. In this paper we show how optical manipulation, imaging and microfluidics can be combined for investigations of single cells. Microfluidic systems have been fabricated and are used, in combination with optical tweezers, to enable environmental changes for single cells. The environment within the microfluidic system has been modelled to ensure control of the process. Three biological model systems have been studied with different combinations of optical manipulation, imaging techniques and microfluidics. In Saccharomyces cerevisiae, environmentally induced size modulations and spatial localization of proteins have been studied to elucidate various signalling pathways. In a similar manner the oxygenation cycle of single red blood cells was triggered and mapped using Raman spectroscopy. In the third experiment the forces between the endoplasmic reticulum and chloroplasts were studied in Pisum sativum and Arabidopsis thaliana. By combining different techniques we make advanced biological research possible, revealing information on a cellular level that is impossible to obtain with traditional techniques.

  11. Study of optical properties and proteoglycan content of tendons by polarization sensitive optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Yang, Ying; Rupani, Asha; Bagnaninchi, Pierre; Wimpenny, Ian; Weightman, Alan

    2012-08-01

    The highly orientated collagen fibers in tendons play a critical role for transferring tensile stress, and they demonstrate birefringent optical properties. However, the influence that proteoglycans (PGs) have on the optical properties of tendons is yet to be fully elucidated. PGs are the essential components of the tendon extracellular matrix; the changes in their quantities and compositions have been associated with tendinopathies. In this study, polarization sensitive optical coherence tomography (PS-OCT) has been used to reveal the relationship between PG content/location and birefringence properties of tendons. Fresh chicken tendons were imaged at regular intervals by PS-OCT and polarization light microscopy during the extraction of PGs, using guanidine hydrochloride (GuHCl). Complementary time-lapsed images taken from the two modalities mutually demonstrated that the extraction of PGs disturbed the local organization of collagen bundles. This corresponded with a decrease in birefringence and associated banding pattern observed by PS-OCT. Furthermore, this study revealed there was a higher concentration of PGs in the outer sheath region than in the fascicles, and therefore the change in birefringence was reduced when extraction was performed on unsheathed tendons. The results provide new insights of tendon structure and the role of PGs on the structural stability of tendons, which also demonstrates the great potential for using PS-OCT as a diagnostic tool to examine tendon pathology.

  12. CCD-camera-based diffuse optical tomography to study ischemic stroke in preclinical rat models

    NASA Astrophysics Data System (ADS)

    Lin, Zi-Jing; Niu, Haijing; Liu, Yueming; Su, Jianzhong; Liu, Hanli

    2011-02-01

    Stroke, due to ischemia or hemorrhage, is the neurological deficit of cerebrovasculature and is the third leading cause of death in the United States. More than 80 percent of stroke patients are ischemic stroke due to blockage of artery in the brain by thrombosis or arterial embolism. Hence, development of an imaging technique to image or monitor the cerebral ischemia and effect of anti-stoke therapy is more than necessary. Near infrared (NIR) optical tomographic technique has a great potential to be utilized as a non-invasive image tool (due to its low cost and portability) to image the embedded abnormal tissue, such as a dysfunctional area caused by ischemia. Moreover, NIR tomographic techniques have been successively demonstrated in the studies of cerebro-vascular hemodynamics and brain injury. As compared to a fiberbased diffuse optical tomographic system, a CCD-camera-based system is more suitable for pre-clinical animal studies due to its simpler setup and lower cost. In this study, we have utilized the CCD-camera-based technique to image the embedded inclusions based on tissue-phantom experimental data. Then, we are able to obtain good reconstructed images by two recently developed algorithms: (1) depth compensation algorithm (DCA) and (2) globally convergent method (GCM). In this study, we will demonstrate the volumetric tomographic reconstructed results taken from tissuephantom; the latter has a great potential to determine and monitor the effect of anti-stroke therapies.

  13. A cross-sectional analytic study of postpartum health care service utilization in the Philippines.

    PubMed

    Yamashita, Tadashi; Suplido, Sherri Ann; Ladines-Llave, Cecilia; Tanaka, Yuko; Senba, Naomi; Matsuo, Hiroya

    2014-01-01

    The maternal mortality ratio in the Philippines remains high; thus, it will be difficult to achieve the Millennium Development Goals 5 by 2015. Approximately two-thirds of all maternal deaths occur during the postpartum period. Therefore, we conducted the present study to examine the current state of postpartum health care service utilization in the Philippines, and identify challenges to accessing postpartum care. A questionnaire and knowledge test were distributed to postpartum women in the Philippines. The questionnaire collected demographical characteristics and information about their utilization of health care services during pregnancy and the postpartum period. The knowledge test consisted of 11 questions regarding 6 topics related to possible physical and mental symptoms after delivery. Sixty-four questionnaires and knowledge tests were analyzed. The mean time of first postpartum health care visit was 5.1 ± 5.2 days after delivery. Postpartum utilization of health care services was significantly correlated with delivery location (P<0.01). Women who delivered at home had a lower rate of postpartum health care service utilization than women who delivered at medical facilities. The majority of participants scored low on the knowledge test. We found inadequate postpartum health care service utilization, especially for women who delivered at home. Our results also suggest that postpartum women lack knowledge about postpartum health concerns. In the Philippines, Barangay health workers may play a role in educating postpartum women regarding health care service utilization to improve their knowledge of possible concerns and their overall utilization of health care services.

  14. Health care utilization in patients with gout: a prospective multicenter cohort study.

    PubMed

    Singh, Jasvinder A; Bharat, Aseem; Khanna, Dinesh; Aquino-Beaton, Cleopatra; Persselin, Jay E; Duffy, Erin; Elashoff, David; Khanna, Puja P

    2017-05-31

    All published studies of health care utilization in gout have been cross-sectional to date, and most used a patient-reported diagnosis of gout. Our objective was to assess health care utilization and its predictors in patients with physician-confirmed gout in a prospective cohort study. In a multi-center prospective cohort study of U.S. veterans with rheumatologist-confirmed gout (N = 186; two centers), we assessed patient self-reported overall and gout-specific health care utilization with the Gout Assessment Questionnaire (GAQ) every 3-months for a 9-month period. Comparisons were made using the student's t test or the chi-square, Wilcoxon rank sum test or Fisher exact test, as appropriate. Mixed effects Poisson regression was used to assess potential correlates of gout-related health care utilization. Mean age was 64.6 years, 98% were men, 13% Hispanic or Latino, 32% were African-American, 6% did not graduate high school, mean serum urate was 8.3 and mean Deyo-Charlson score was 3.1. During the past year, mean gout-related visits were as follows: rheumatologist, 1.5; primary care physician, 2 visits; ≥1 inpatient visits, 7%; ≥1 ER visits, 26%; and urgent care/walk-in visit, 33%. In longitudinal analyses, African-American race and gout flares in the last 3 months were associated with significantly higher rate ratio of gout-related outpatient visits. African-American race and lack of college education were associated with significantly higher rate ratio for gout-related urgent visits and overnight stays. African-American race and recent gout flares were associated with higher outpatient utilization and African-American race and no college education with higher urgent or inpatient utilization. Future studies should examine whether modifiable predictors of utilization can be targeted to reduce healthcare utilization in patients with gout.

  15. Financial Analysis of Incentive Mechanisms to Promote Energy Efficiency: Case Study of a Prototypical Southwest Utility

    SciTech Connect

    Cappers, Peter; Goldman, Charles; Chait, Michele; Edgar, George; Schlegel, Jeff; Shirley, Wayne

    2009-03-04

    Many state regulatory commissions and policymakers want utilities to aggressively pursue energy efficiency as a strategy to mitigate demand and energy growth, diversify the resource mix, and provide an alternative to building new, costly generation. However, as the National Action Plan for Energy Efficiency (NAPEE 2007) points out, many utilities continue to shy away from aggressively expanding their energy efficiency efforts when their shareholder's fundamental financial interests are placed at risk by doing so. Thus, there is increased interest in developing effective ratemaking and policy approaches that address utility disincentives to pursue energy efficiency or lack of incentives for more aggressive energy efficiency efforts. New regulatory initiatives to promote increased utility energy efficiency efforts also affect the interests of consumers. Ratepayers and their advocates are concerned with issues of fairness, impacts on rates, and total consumer costs. From the perspective of energy efficiency advocates, the quid pro quo for utility shareholder incentives is the obligation to acquire all, or nearly all, achievable cost-effective energy efficiency. A key issue for state regulators and policymakers is how to maximize the cost-effective energy efficiency savings attained while achieving an equitable sharing of benefits, costs and risks among the various stakeholders. In this study, we modeled a prototypical vertically-integrated electric investor-owned utility in the southwestern US that is considering implementing several energy efficiency portfolios. We analyze the impact of these energy efficiency portfolios on utility shareholders and ratepayers as well as the incremental effect on each party when lost fixed cost recovery and/or utility shareholder incentive mechanisms are implemented. A primary goal of our quantitative modeling is to provide regulators and policymakers with an analytic framework and tools that assess the financial impacts of

  16. A study of neutron and gamma radiation effects on transmission of various types of glasses, optical coatings, cemented optics and fiber

    NASA Astrophysics Data System (ADS)

    Javed Akhtar, S. M.; Ashraf, Mohammad; Khan, Shaukat Hameed

    2007-08-01

    A study of radiation effects on various types of glasses, dielectric optical coatings, cemented optics and fiber was undertaken with a view to select them for extreme radiation environments. Samples were exposed to different radiation doses in the Pakistan Research Reactor-I (PARR-I) for neutron and Cobalt 60 source for gamma irradiation. Transmissions were measured before and after irradiation. The dielectric coatings were subjected to additional tests (adhesion, abrasion and humidity, etc.) as per MIL-M-13508C and MIL-C-675C. All 15 glasses studied showed varying amounts of transmission loss as expected, with negligible degradation for three types. Recovery of transmissions with time/ageing was also studied, with more or less complete recovery with temperature annealing. A faster bleaching of darkened/brown glasses was achieved by using UV lamps or UV laser. The dielectric coatings (HR, AR) and one of the two commercial optical cements showed excellent resistance to neutrons and gamma radiations, and could be good candidates for the fabrication and utilization of optical components in extreme radiation environments. The data allowed several Chinese glasses to be studied for the first time.

  17. Optical closure study on light-absorbing aerosols

    NASA Astrophysics Data System (ADS)

    Petzold, Andreas; Bundke, Ulrich; Freedman, Andrew; Onasch, Timothy B.; Massoli, Paola; Andrews, Elizabeth; Hallar, Anna G.

    2014-05-01

    The in situ measurement of atmospheric aerosol optical properties is an important component of quantifying climate change. In particular, the in-situ measurement of the aerosol single-scattering albedo (SSA), which is the ratio of aerosol scattering to aerosol extinction, is identified as a key challenge in atmospheric sciences and climate change research. Ideally, the complete set of aerosol optical properties is measured through optical closure studies which simultaneous measure aerosol extinction, scattering and absorption coefficients. The recent development of new optical instruments have made real-time in situ optical closure studies attainable, however, many of these instruments are state-of-the-art but not practical for routine monitoring. In our studies we deployed a suit of well-established and recently developed instruments including the cavity attenuated phase shift (CAPS) method for aerosol light extinction, multi-angle absorption photometer (MAAP) and particle soot absorption photometer (PSAP) for aerosol light absorption, and an integrating nephelometer (NEPH) for aerosol light scattering measurements. From these directly measured optical properties we calculated light absorption from extinction minus scattering (difference method), light extinction from scattering plus absorption, and aerosol single-scattering albedo from combinations CAPS + MAAP, NEPH + PSAP, NEPH + MAAP, CAPS + NEPH. Closure studies were conducted for laboratory-generated aerosols composed of various mixtures of black carbon (Regal 400R pigment black, Cabot Corp.) and ammonium sulphate, urban aerosol (Billerica, MA), and background aerosol (Storm Peak Lab.). Key questions addressed in our closure studies are: (1) how well can we measure aerosol light absorption by various methods, and (2) how well can we measure the aerosol single-scattering albedo by various instrument combinations? In particular we investigated (3) whether the combination of a CAPS and NEPH provides a reasonable

  18. Optical trapping studies of acto-myosin motor proteins

    NASA Astrophysics Data System (ADS)

    Farrow, Rachel E.; Rosenthal, Peter B.; Mashanov, Gregory I.; Holder, Anthony A.; Molloy, Justin E.

    2007-09-01

    Optical tweezers have been used extensively to measure the mechanical properties of individual biological molecules. Over the past 10-15 years optical trapping studies have revealed important information about the way in which motor proteins convert chemical energy to mechanical work. This paper focuses on studies of the acto-myosin motor system that is responsible for muscle contraction and a host of other cellular motilities. Myosin works by binding to filamentous actin, pulling and then releasing. Each cycle of interaction produces a few nanometres movement and a few piconewtons force. Individual interactions can be observed directly by holding an individual actin filament between two optically trapped microspheres and positioning it in the immediate vicinity of a single myosin motor. When the chemical fuel (adenosine triphosphate or ATP) is present the myosin undergoes repeated cycles of interaction with the actin filament producing square-wave like displacements and forces. Analysis of optical trapping data sets enables the size and timing of the molecular motions to be deduced.

  19. Non-linear optical studies of adsorbates: Spectroscopy and dynamics

    SciTech Connect

    Zhu, Xiangdong.

    1989-08-01

    In the first part of this thesis, we have established a systematic procedure to apply the surface optical second-harmonic generation (SHG) technique to study surface dynamics of adsorbates. In particular, we have developed a novel technique for studies of molecular surface diffusions. In this technique, the laser-induced desorption with two interfering laser beams is used to produce a monolayer grating of adsorbates. The monolayer grating is detected with diffractions of optical SHG. By monitoring the first-order second-harmonic diffraction, we can follow the time evolution of the grating modulation from which we are able to deduce the diffusion constant of the adsorbates on the surface. We have successfully applied this technique to investigate the surface diffusion of CO on Ni(111). The unique advantages of this novel technique will enable us to readily study anisotropy of a surface diffusion with variable grating orientation, and to investigate diffusion processes of a large dynamic range with variable grating spacings. In the second part of this work, we demonstrate that optical infrared-visible sum-frequency generation (SFG) from surfaces can be used as a viable surface vibrational spectroscopic technique. We have successfully recorded the first vibrational spectrum of a monolayer of adsorbates using optical infrared-visible SFG. The qualitative and quantitative correlation of optical SFG with infrared absorption and Raman scattering spectroscopies are examined and experimentally demonstrated. We have further investigated the possibility to use transient infrared-visible SFG to probe vibrational transients and ultrafast relaxations on surfaces. 146 refs.

  20. Structural and optical studies on selected web spinning spider silks.

    PubMed

    Karthikeyani, R; Divya, A; Mathavan, T; Asath, R Mohamed; Benial, A Milton Franklin; Muthuchelian, K

    2017-01-05

    This study investigates the structural and optical properties in the cribellate silk of the sheet web spider Stegodyphus sarasinorum Karsch (Eresidae) and the combined dragline, viscid silk of the orb-web spiders Argiope pulchella Thorell (Araneidae) and Nephila pilipes Fabricius (Nephilidae). X-ray diffraction (XRD), Fourier transform infra-red (FTIR), Ultraviolet-visible (UV-Vis) and fluorescence spectroscopic techniques were used to study these three spider silk species. X-ray diffraction data are consistent with the amorphous polymer network which is arising from the interaction of larger side chain amino acid contributions due to the poly-glycine rich sequences known to be present in the proteins of cribellate silk. The same amorphous polymer networks have been determined from the combined dragline and viscid silk of orb-web spiders. From FTIR spectra the results demonstrate that, cribellate silk of Stegodyphus sarasinorum, combined dragline viscid silk of Argiope pulchella and Nephila pilipes spider silks are showing protein peaks in the amide I, II and III regions. Further they proved that the functional groups present in the protein moieties are attributed to α-helical and side chain amino acid contributions. The optical properties of the obtained spider silks such as extinction coefficients, refractive index, real and imaginary dielectric constants and optical conductance were studied extensively from UV-Vis analysis. The important fluorescent amino acid tyrosine is present in the protein folding was investigated by using fluorescence spectroscopy. This research would explore the protein moieties present in the spider silks which were found to be associated with α-helix and side chain amino acid contributions than with β-sheet secondary structure and also the optical relationship between the three different spider silks are investigated. Successful spectroscopic knowledge of the internal protein structure and optical properties of the spider silks could

  1. Structural and optical studies on selected web spinning spider silks

    NASA Astrophysics Data System (ADS)

    Karthikeyani, R.; Divya, A.; Mathavan, T.; Asath, R. Mohamed; Benial, A. Milton Franklin; Muthuchelian, K.

    2017-01-01

    This study investigates the structural and optical properties in the cribellate silk of the sheet web spider Stegodyphus sarasinorum Karsch (Eresidae) and the combined dragline, viscid silk of the orb-web spiders Argiope pulchella Thorell (Araneidae) and Nephila pilipes Fabricius (Nephilidae). X-ray diffraction (XRD), Fourier transform infra-red (FTIR), Ultraviolet-visible (UV-Vis) and fluorescence spectroscopic techniques were used to study these three spider silk species. X-ray diffraction data are consistent with the amorphous polymer network which is arising from the interaction of larger side chain amino acid contributions due to the poly-glycine rich sequences known to be present in the proteins of cribellate silk. The same amorphous polymer networks have been determined from the combined dragline and viscid silk of orb-web spiders. From FTIR spectra the results demonstrate that, cribellate silk of Stegodyphus sarasinorum, combined dragline viscid silk of Argiope pulchella and Nephila pilipes spider silks are showing protein peaks in the amide I, II and III regions. Further they proved that the functional groups present in the protein moieties are attributed to α-helical and side chain amino acid contributions. The optical properties of the obtained spider silks such as extinction coefficients, refractive index, real and imaginary dielectric constants and optical conductance were studied extensively from UV-Vis analysis. The important fluorescent amino acid tyrosine is present in the protein folding was investigated by using fluorescence spectroscopy. This research would explore the protein moieties present in the spider silks which were found to be associated with α-helix and side chain amino acid contributions than with β-sheet secondary structure and also the optical relationship between the three different spider silks are investigated. Successful spectroscopic knowledge of the internal protein structure and optical properties of the spider silks could

  2. Electric-field sensors utilizing coupling between a D-fiber and an electro-optic polymer slab.

    PubMed

    Chadderdon, Spencer; Gibson, Richard; Selfridge, Richard H; Schultz, Stephen M; Wang, Wen C; Forber, Richard; Luo, Jingdong; Jen, Alex K-Y

    2011-07-10

    This paper provides a detailed analysis of electric field sensing using a slab-coupled optical fiber sensor (SCOS). This analysis explains that the best material for the slab waveguide is an inorganic material because of the low RF permittivity combined with the high electro-optic coefficient. The paper also describes the fabrication and testing of a SCOS using an AJL chromophore in amorphous polycarbonate. The high uniform polymer slab waveguide is fabricated using a hot embossing process to create a slab with a thickness of 50 μm. The fabricated polymer SCOS was characterized to have a resonance slope of ΔP/Δλ=6.83E5 W/m and a resonance shift of Δλ/E=1.47E-16 m(2)/V.

  3. A Study of Thermal Analyses and Fundamental Combustion Characteristics for Thermal Utility with Biomass Volatile Matter

    NASA Astrophysics Data System (ADS)

    Ida, Tamio; Namba, Kunihiko; Sano, Hiroshi

    Based on un-use biomass utilities, Carbonized technology is noticed as material utilities and solid fuel. Therefore, this technology is tackling by national project as large-scale utilities. But, this technology is dehydrated volatiles matter during carbonized from biomass. Especially, Woody tar into one of volatile matter has vicious handling to get into trouble in carbonized equipment. In this study, we propose to get fundamental knowledge for effective thermal utility through thermal decompositions and fundamental combustion properties on experimental results. Woody tar has high caloric value (approximately 30MJ/kg) and high carbon ration. On the other hand, a woody vinegar liquid has thermal decomposition property close to water property with heat absorption as evaporation latent heat of water. In fundamental combustion experimental result, a woody tar has fl ammable combustion and surface combustion. Especially, a total combustion and ignition time properties has hyperbola relation to environment temperatures in furnace.

  4. Nonlinear Optical Studies of Relaxation in Semiconductor Microstructures.

    NASA Astrophysics Data System (ADS)

    Remillard, Jeffrey Thomas

    The purpose of this research is to study the relaxation of optically generated excitons and carriers in semiconductor microstructures using four wave mixing (FWM) spectroscopy. The systems studied include CdSSe microcrystallite doped glasses and GaAs/AlGaAs multiple quantum well structures (MQWS). Exposing a semiconductor to optical radiation near the fundamental band gap results in the creation of populations of elementary excitations including electrons, holes, and excitons, and also results in the creation of a superposition state between the ground and excited state of the solid. The work in this dissertation examines the relaxation of the populations of elementary excitations and the relaxation of the coherence between the ground and excited state using four wave mixing spectroscopy. First, the nonlinear optical response of simple two level systems is examined in order to provide insight into the types of line shapes expected from semiconductors. It is shown that the line shape is strongly dependent on how the system is coupled to the reservoir and the consequences of coupling to a reservoir are examined in a FWM measurement made in atomic sodium. The first semiconductor system studied is CdSSe microcrystallite doped glass. This system is shown to have a very slow component to the nonlinear response which has a optical intensity dependence and temperature dependence which suggests that the FWM response in these materials is trap mediated. Room temperature FWM measurements in GaAs MQWS enables the measurement of the carrier recombination time and the ambipolar diffusion coefficient. Using the technique of correlated optical fields, a slow component to the nonlinear response was measured showing an interference profile which suggests a possible shift of the exciton resonance due to the optically generated carriers. At low temperatures (2-20 K), measurements of the exciton line shape and relaxation time were made and evidence for exciton spectral diffusion was

  5. 7x 40 Gb/s base-rate RZ all-optical broadcasting utilizing an electroabsorption modulator.

    PubMed

    Xu, L; Chi, N; Yvind, K; Christiansen, L; Oxenløwe, L; Mørk, J; Jeppesen, P; Hanberg, J

    2004-02-09

    We experimentally demonstrate all-optical broadcasting through simultaneous 7 x 40 Gb/s base-rate wavelength conversion in RZ format based on cross absorption modulation in an electroabsorption modulator. In this experiment the original intensity-modulated information is successfully duplicated onto seven wavelengths that comply with the ITU-T proposal. The advantages of the proposed wavelength conversion scheme are also discussed.

  6. Synthesis & Studies of New Non-Destructive Read-Out Materials for Optical Storage and Optical Switches

    DTIC Science & Technology

    2005-12-31

    studied This organic storage system, consists of two different molecular components chemically bonded to each other, a polar photochromic fulgimide...and an oxazine dye, to form a composite molecule that retains the photochromic and spectroscopic properties of each individual molecular component yet...15. NUMBER OF PAGES Optical Storage media, Non-destructive readout materials, 20 3D optical storage, Photochromic composite molecule, Optical 16

  7. Clinical study of bladder diseases using optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Zagainova, Elena; Gladkova, Natalia D.; Strelzova, O.; Sumin, A.; Gelikonov, Grigory V.; Feldchtein, Felix I.; Iksanov, Rashid R.

    2000-11-01

    Optical Coherence Tomography (OCT), a new optical bioimaging technique was used to evaluate the state of mucosa in the urinary bladder. The state of mucosa of the bladder was evaluated in patients with prostatic adenoma (11 male patients) during the course of prostatectomy operation via a resection cytoscope. An OCT probe was inserted into the biopsy channel of a cystoscope. The sites to be imaged by OCT were determined visually and, after OCT study, underwent excisional biopsy and subsequent histological examination. Children (9 girls) were examined during diagnostic cystoscopy. Our analysis of diagnostic capabilities of OCT in urology relies on the comparison of OCT information on normal and morphologically altered tissues. OCT is able to provide objective data concerning the structure of mucosa of the bladder due to the difference in optical properties of different layers in tissue. The epithelium and the layers of connective tissue, both in norm and pathology, are clearly visualized in the tomograms. Our OCT study of healthy mucosa of the urinary bladder has demonstrated that the epithelium appears in the tomograms as an upper highly backscattering layer. An underlying optically less transparent layer, much greater in size than the previous one, corresponds to the connective tissue of the mucosa. Inside this layer, elongated poorly backscattering formations with clear contours are seen; they do not alter the longitudinal structure of the submucosal layer. These formations are blood vessels. Optical patterns characteristic of chronic inflammation are obtained. They correspond, as confirmed histologically, to liquid accumulation, cellular infiltration of mucosal layers, hypervascularization, and fibrosis. OCT information on proliferative processes, such as papillomatosis of the urinary bladder and squamous cell carcinoma, is analyzed. It is shown that OCT can reliably reveal edema of the mucous membrane of the bladder and identify the character of appearing

  8. Optical digital microscopy for cyto- and hematological studies in vitro

    NASA Astrophysics Data System (ADS)

    Ganilova, Yu. A.; Dolmashkin, A. A.; Doubrovski, V. A.; Yanina, I. Yu.; Tuchin, V. V.

    2013-08-01

    The dependence of the spatial resolution and field of view of an optical microscope equipped with a CCD camera on the objective magnification has been experimentally investigated. Measurement of these characteristics has shown that a spatial resolution of 20-25 px/μm at a field of view of about 110 μm is quite realistic; this resolution is acceptable for a detailed study of the processes occurring in cell. It is proposed to expand the dynamic range of digital camera by measuring and approximating its light characteristics with subsequent plotting of the corresponding calibration curve. The biological objects of study were human adipose tissue cells, as well as erythrocytes and their immune complexes in human blood; both objects have been investigated in vitro. Application of optical digital microscopy for solving specific problems of cytology and hematology can be useful in both biomedical studies in experiments with objects of nonbiological origin.

  9. Imaging studies for diagnosing Graves' orbitopathy and dysthyroid optic neuropathy.

    PubMed

    Gonçalves, Allan C Pieroni; Gebrim, Eloísa M M S; Monteiro, Mário L R

    2012-11-01

    Although the diagnosis of Graves' orbitopathy is primarily made clinically based on laboratory tests indicative of thyroid dysfunction and autoimmunity, imaging studies, such as computed tomography, magnetic resonance imaging, ultrasound and color Doppler imaging, play an important role both in the diagnosis and follow-up after clinical or surgical treatment of the disease. Imaging studies can be used to evaluate morphological abnormalities of the orbital structures during the diagnostic workup when a differential diagnosis versus other orbital diseases is needed. Imaging may also be useful to distinguish the inflammatory early stage from the inactive stage of the disease. Finally, imaging studies can be of great help in identifying patients prone to develop dysthyroid optic neuropathy and therefore enabling the timely diagnosis and treatment of the condition, avoiding permanent visual loss. In this paper, we review the imaging modalities that aid in the diagnosis and management of Graves' orbitopathy, with special emphasis on the diagnosis of optic nerve dysfunction in this condition.

  10. A case-comparison study of automatic document classification utilizing both serial and parallel approaches

    NASA Astrophysics Data System (ADS)

    Wilges, B.; Bastos, R. C.; Mateus, G. P.; Dantas, M. A. R.

    2014-10-01

    A well-known problem faced by any organization nowadays is the high volume of data that is available and the required process to transform this volume into differential information. In this study, a case-comparison study of automatic document classification (ADC) approach is presented, utilizing both serial and parallel paradigms. The serial approach was implemented by adopting the RapidMiner software tool, which is recognized as the worldleading open-source system for data mining. On the other hand, considering the MapReduce programming model, the Hadoop software environment has been used. The main goal of this case-comparison study is to exploit differences between these two paradigms, especially when large volumes of data such as Web text documents are utilized to build a category database. In the literature, many studies point out that distributed processing in unstructured documents have been yielding efficient results in utilizing Hadoop. Results from our research indicate a threshold to such efficiency.

  11. A comparative study of optical concentrators for visible light communications

    NASA Astrophysics Data System (ADS)

    Mulyawan, Rahmat; Gomez, Ariel; Chun, Hyunchae; Rajbhandari, Sujan; Manousiadis, Pavlos P.; Vithanage, Dimali A.; Faulkner, Grahame; Turnbull, Graham A.; Samuel, Ifor D. W.; Collins, Stephen; O'Brien, Dominic

    2017-01-01

    Given the imminent radio frequency spectrum crunch, Visible Light Communication (VLC) is being proposed as an alternative wireless technology allowing for scalable connectivity to potentially millions of mobile and Internet-of- Things (IoT) devices. A VLC system uses a photo-detector (PD) receiver that converts the optically modulated light from a light source into a modulated electrical signal. The corresponding receiver electrical bandwidth is typically inversely proportional to the PD active area. Consequently, to construct a high-speed VLC link, the PD active area is often substantially reduced and an optical concentrator is used to enhance the receiver collection area. However, to achieve high concentrating factor, the link field-of-view (FOV) needs to be narrow due to the étendue conservation in linear passive optical systems. This paper studies a Fluorescent Concentrator (FC) that breaks this étendue conservation. The FC is not only based on reflective and refractive principles but also makes use of fluorescence process. A comparison between the FC and conventional optical concentrators, namely Compound Parabolic Concentrator (CPC) is also investigated. The trade-off between received signal strength and incoming link angle is demonstrated over 60° coverage. Experimental results show that performance degradation as the link angle increases using FC-based receivers is significantly lower than for conventional CPC.

  12. Physical, Optical absorption and EPR studies on fluoro- bismuthate glasses

    NASA Astrophysics Data System (ADS)

    Srinivasu, Ch; Samee, M. A.; Edukondalu, A.; Laxmi Kanth, C.; Rahman, Syed

    2015-02-01

    Glasses of the xLiF-(50-x)Li2O-20SrO-30Bi2O3 system, with 0 <= x <= 20 mole % were studied by EPR and Optical measurements. The changes in both density and molar volume indicate structural modifications occur due to addition of LiF. The glass transition temperatures are observed to decrease with an increase in LiF content in the compositions. The local structure around Cu2+ ions has been examined by means of electron paramagnetic resonance and optical absorption measurements. It is observed that the spin-Hamiltonian parameters calculated from the EPR spectra are influenced by the glass composition. The Cu2+ ions are in well-defined axial sites but subjected to small distortion leading to the broadening of the spectra. The spin-Hamiltonian parameter values indicate that the ground state of Cu2+ is and the site symmetry around Cu2+ ions is tetragonally distorted octahedral. The optical absorption spectra exhibited a broad band corresponding to the d-d transition bands of Cu2+ ion. By correlating EPR and optical absorption data, the bond parameters are evaluated.

  13. Study on a new type optic-electric transformer

    NASA Astrophysics Data System (ADS)

    Li, Weikai; Zheng, Shengxuan

    2006-02-01

    This paper presents an optic-electronic voltage transformer insulated by SF6, Which is applied in 500KV (line voltage) power system. The voltage sensor is based on converse piezoelectric effect in a quartz crystal. High voltage is exerted on the quartz crystal after being divided by cylinder capacitor divider, piezoelectric deformation is sensed by elliptical-core dual-mode fiber around the surface of cylindrical crystal, the differential phase shift of light wave is recovered by means of two spatial modes (LP01 mode and even LP11 mode) transmitted in the optical fiber and interrogated by low-coherence interferometer. Except for capacitor divider, quartz crystal, it is a whole optical fiber scheme, no separated optical devices, such as: collimators, polarizer and wave plates; Thus the cost of sensor is reduced, accuracy is advanced, and it is convenient for production in scale. Finally, the paper offers a design scheme for the voltage transformers' system and insulator, studies the performance of voltage transformer and provides a theory gist for the application of high voltage transformer.

  14. Self-Reported Utilization of Eye Care among Latinos: The Los Angeles Latino Eye Study (LALES)

    PubMed Central

    Morales, Leo S.; Varma, Rohit; Paz, Sylvia H.; Lai, Mei Ying; Mazhar, Kashif; Andersen, Ronald M.; Azen, Stanley P.

    2009-01-01

    Purpose To identify the prevalence and determinants of self-reported eye care utilization in Latinos. Design Population-based ocular epidemiological study in Latinos age 40+ living in La Puente, California. Participants 5,455 participants. Methods Univariate, multivariable and stepwise logistic regression analyses were conducted to identify predisposing, enabling and need variables associated with self-reported eye care utilization. Main Outcome Measures Prevalence of self-reported utilization: eye care visit, having had a dilated examination in the past 12 months, ever having had a dilated examination, and odds ratios for factors associated with self-reported utilization. Results Overall, 36% of participants reported an eye care visit and 19% reported having a dilated examination in the past year. Fifty-seven percent reported ever having had a dilated eye examination. Greater eye care utilization was associated with older age, female gender, bilingual language proficiency (English and Spanish), more education, having health insurance, having a usual place for care, having a regular provider of care, greater number of co-morbidities, visual impairment, and lower vision-specific quality of life scores. Conclusions Increasing utilization and access to eye care for Latinos should be a priority because visual impairment has significant impacts on well-being and mortality. PMID:20018380

  15. Impact of Atrial Fibrillation on Healthcare Utilization in the Community: The Atherosclerosis Risk in Communities Study

    PubMed Central

    Bengtson, Lindsay G. S.; Lutsey, Pamela L.; Loehr, Laura R.; Kucharska‐Newton, Anna; Chen, Lin Y.; Chamberlain, Alanna M.; Wruck, Lisa M.; Duval, Sue; Stearns, Sally C.; Alonso, Alvaro

    2014-01-01

    Background Atrial fibrillation (AF) is associated with increased risk of hospitalization. Little is known about the impact of AF on utilization of noninpatient health care or about sex or race differences in AF‐related utilization. We examined rates of inpatient and outpatient utilization by AF status in the Atherosclerosis Risk in Communities study. Methods and Results Participants with incident AF enrolled in fee‐for‐service Medicare for at least 12 continuous months between 1991 and 2009 (n=932) were matched on age, sex, race and field center with up to 3 participants without AF (n=2729). Healthcare utilization was ascertained from Medicare claims and classified by primary International Classification of Diseases, ninth revision code. The average annual numbers of days hospitalized were 13.2 (95% CI 11.6 to 15.0) and 2.8 (95% CI 2.5 to 3.1) for those with and without AF, respectively. The corresponding numbers of annual outpatient claims were 53.3 (95% CI 50.5 to 56.3) and 22.9 (95% CI 22.1 to 23.8) for those with and without AF, respectively. Most utilization among AF patients was attributable to non‐AF conditions. The adjusted rate ratio for annual days hospitalized for other cardiovascular disease–related reasons was 4.58 (95% CI: 3.41 to 6.16) for those with AF versus those without AF. The association between AF and healthcare utilization was similar among men and women and among white and black participants. Conclusions Participants with AF had considerably greater healthcare utilization, and the difference in utilization for other cardiovascular disease–related reasons was substantial. In addition to rate or rhythm treatment, AF management should focus on the accompanying cardiovascular comorbidities. PMID:25359400

  16. Optical and spectroscopic study of erbium doped calcium borotellurite glasses

    NASA Astrophysics Data System (ADS)

    Gomes, J. F.; Lima, A. M. O.; Sandrini, M.; Medina, A. N.; Steimacher, A.; Pedrochi, F.; Barboza, M. J.

    2017-04-01

    In this study, 10CaF2 - (29.9-0.4x)CaO - (60-0.6x)B2O3 - xTeO2 - 0,1Er2O3 (x = 10, 16, 22, 30 and 50 mol %) glasses were synthesized, and their optical and spectroscopic properties were investigated. X-ray diffraction, density, glass transition temperature (Tg), crystallization temperature (Tx), refraction index, luminescence, radiative lifetime and optical absorption measurements were carried out. Molar volume (Vm), thermal stability (Tx-Tg), electronic polarizability (αm), optical bang gap energy (Eg) and Judd-Ofelt (JO) parameters Ωt (2,4,6) were also calculated. The results are discussed in terms of tellurium oxide content. The increase of TeO2 in the glasses composition increases density, refractive index and electronic polarizability. The optical band gap energy decreases varying from 3.37 to 2.71 eV for the glasses with 10 and 50 mol% of TeO2, respectively. The optical absorption coefficient spectra show characteristic bands of Er3+ ions. Furthermore, these spectra in NIR region show a decrease of hydroxyl groups as a function of TeO2 addition. Luminescence intensity and radiative lifetimes at 1530 nm show an increasing with the TeO2 content. The JO parameters of Er:CaBTeX glasses follow the trend Ω2 > Ω4 > Ω6 and the quality factor values (Ω4/Ω6) were between 1.37 and 3.07. By comparing the measured lifetime with the calculated radiative decay time, quantum efficiency was calculated. The luminescence emission intensity at 1530 nm decreases with the increase of temperature. The lifetime values show a slight trend to decrease with the temperature increase, from 300 to 420 K, for all the samples.

  17. Differentiation of glaucomatous optic discs with different appearances using optic disc topography parameters: The Glaucoma Stereo Analysis Study

    PubMed Central

    Tanito, Masaki; Nitta, Koji; Katai, Maki; Kitaoka, Yasushi; Yokoyama, Yu; Omodaka, Kazuko; Nakazawa, Toru

    2017-01-01

    The Glaucoma Stereo Analysis Study (GSAS) is a multicenter collaborative study of the characteristics of glaucomatous optic disc morphology using a stereo fundus camera. Using GSAS dataset, the formulas for predicting different glaucomatous optic disc appearances were established. The GSAS dataset containing three-dimensionally-analyzed optic disc topographic parameters from 187 eyes with primary open-angle glaucoma was assessed with discrimination analyses to obtain formulas predictive of glaucomatous optic disc appearances: focal ischemic (FI); generalized enlargement (GE), myopic glaucomatous (MY), and senile sclerotic (SS). Using 38 optic disc parameters-substituted discrimination analyses with a stepwise forward-selection method, six parameters (temporal and nasal rim-disc ratios, mean cup depth, height variation contour, disc tilt angle, and rim decentering absolute) were selected into the formulas. The area under the receiver operating characteristic curves for predicting the four disc types with established formulas were 0.88, 0.91, 0.93, and 0.86 for FI, MY, SS, and GE, respectively. Age, visual acuity, refractive error, glaucoma (normal or high-tension glaucoma), and baseline intraocular pressure differed significantly among the four optic disc types, suggesting the appearances represent different clinical glaucoma phenotypes. Using six optic disc topographic parameters obtained by stereo fundus camera, the GSAS classification formulas predicted and quantified each component of different optic disc appearances in each eye and provided a novel parameter to describe glaucomatous optic disc characteristics. PMID:28178303

  18. Using optical tweezers to study mechanical properties of collagen

    NASA Astrophysics Data System (ADS)

    Rezaei, Naghmeh; Downing, Benjamin P. B.; Wieczorek, Andrew; Chan, Clara K. Y.; Welch, Robert Lindsay; Forde, Nancy R.

    2011-08-01

    The mechanical response of biological molecules at the microscopic level contributes significantly to their function. Optical tweezers are instruments that enable scientists to study mechanical properties at microscopic levels. They are based on a highly focused laser beam that creates a trap for microscopic objects such as dielectric spheres, viruses, bacteria, living cells and organelles, and then manipulates them by applying forces in the picoNewton range (a range that is biologically relevant). In this work, mechanical properties of single collagen molecules are studied using optical tweezers. We discuss the challenges of stretching single collagen proteins, whose length is much less than the size of the microspheres used as manipulation handles, and show how instrumental design and biochemistry can be used to overcome these challenges.

  19. Comparison of three optical methods to study erythrocyte aggregation.

    PubMed

    Zhao, H; Wang, X; Stoltz, J F

    1999-01-01

    The aim of this work was to evaluate three optical methods designed to determine erythrocyte aggregation: Erythroaggregometer (EA; Regulest, France), Laser-assisted Optical Rotational Cell Analyzer (LORCA; Mechatronics, Netherlands) and Fully Automatic Erythrocyte Aggregometer (FAEA; Myrenne, GmbH, Germany). Blood samples were taken from fifty donors (26 males and 24 females). The aggregation of normal red blood cell (RBC) and RBCs suspended in three normo- and hyperaggregating suspending media was studied. The results revealed some significant correlations between parameters measured by these instruments, in particular, between the indexes of aggregation of EA and LORCA. Further, RBC aggregation of multiple myeloma patients was also studied and a hyper erythrocyte aggregation state was found by EA and LORCA.

  20. Spatially selective photocoagulation of biological tissues: feasibility study utilizing cryogen spray cooling

    SciTech Connect

    Anvari, B. |; Tanenbaum, B.S.; Milner, T.E.; Tang, K.; Liaw, L.; Kalafus, K.; Kimel, S.; Nelson, J.S.

    1996-07-01

    Successful laser treatment of selected dermatoses such as hemangiomas requires thermally induced damage to blood vessels while protecting the epidermis. We present and test a procedure in a rabbit liver tissue model that utilizes cryogen spray cooling during continuous Nd:YAG laser irradiation to induce deep photocoagulation necrosis while protecting superficial tissues from thermal injury. Gross and histologic observations are consistent with calculated thicknesses of protected and photocoagulated tissues and demonstrate the feasibility of inducing spatially selective photocoagulation when cryogen spray cooling is used in conjunction with laser irradiation. This procedure may be useful in the thermal treatment of some pathological conditions for which it is desired that deep photocoagulation be induced while protecting superficial tissues. {copyright} {ital 1996 Optical Society of America.}

  1. Modulation of retinal image vasculature analysis to extend utility and provide secondary value from optical coherence tomography imaging

    PubMed Central

    Cameron, James R.; Ballerini, Lucia; Langan, Clare; Warren, Claire; Denholm, Nicholas; Smart, Katie; MacGillivray, Thomas J.

    2016-01-01

    Abstract. Retinal image analysis is emerging as a key source of biomarkers of chronic systemic conditions affecting the cardiovascular system and brain. The rapid development and increasing diversity of commercial retinal imaging systems present a challenge to image analysis software providers. In addition, clinicians are looking to extract maximum value from the clinical imaging taking place. We describe how existing and well-established retinal vasculature segmentation and measurement software for fundus camera images has been modulated to analyze scanning laser ophthalmoscope retinal images generated by the dual-modality Heidelberg SPECTRALIS® instrument, which also features optical coherence tomography. PMID:27175375

  2. Ultra-Wideband Optical Modulation Spectrometer (OMS) Development: Study of the Optical Setup of a Wide-Band Optical Modulation Spectrometer

    NASA Technical Reports Server (NTRS)

    Tolls, Volker; Stringfellow, Guy (Technical Monitor)

    2001-01-01

    The purpose of this study is to advance the design of the optical setup for a wide-band Optical Modulation Spectrometer (OMS) for use with astronomical heterodyne receiver systems. This report describes the progress of this investigation achieved from March until December 2001.

  3. Optical properties of particles in planetary atmospheres - Laboratory studies

    NASA Technical Reports Server (NTRS)

    Williams, D.

    1974-01-01

    The laboratory techniques employed for the determination of optical constants are discussed briefly. The values obtained for the real n and imaginary k parts of the refractive indices of water, ice, and liquid ammonia are presented graphically. Work currently in progress on solid ammonia and on sulphuric acid is discussed. Other approaches to studies of the properties of aerosols in planetary atmospheres are presented briefly.

  4. Optical properties of particles in planetary atmospheres - Laboratory studies

    NASA Technical Reports Server (NTRS)

    Williams, D.

    1974-01-01

    The laboratory techniques employed for the determination of optical constants are discussed briefly. The values obtained for the real n and imaginary k parts of the refractive indices of water, ice, and liquid ammonia are presented graphically. Work currently in progress on solid ammonia and on sulphuric acid is discussed. Other approaches to studies of the properties of aerosols in planetary atmospheres are presented briefly.

  5. Dental optical tomography with upconversion nanoparticles—a feasibility study

    NASA Astrophysics Data System (ADS)

    Long, Feixiao; Intes, Xavier

    2017-06-01

    Upconversion nanoparticles (UCNPs) have the unique ability to emit multiple colors upon excitation by near-infrared (NIR) light. Herein, we investigate the potential use of UCNPs as contrast agents for dental optical tomography, with a focus on monitoring the status of fillings after dental restoration. The potential of performing tomographic imaging using UCNP emission of visible or NIR light is established. This in silico and ex vivo study paves the way toward employing UCNPs as theranostic agents for dental applications.

  6. The study of plant tissue by optical coherent microscopy method

    NASA Astrophysics Data System (ADS)

    Chirskaya, V. V.; Margaryants, N. B.; Zhukova, E. V.

    2016-08-01

    The article presents the results of application of the optical coherent microscopy technique using a high-resolution automatic Linnik interference microscope to study the structure of plant tissues exemplified by surface periderm layers of a tuberous nightshade (solánum tuberosum) bulb. The results of 3D visualization of the structure of the sample under examination are provided. Scanning depth was 32 µm, with axial and lateral resolution of the device 1 µm.

  7. Study of Photochromic Materials for Use in Optical Signal Processing.

    DTIC Science & Technology

    1987-11-01

    LDFP 07 C6 11. TITLE (kIclude Security Classification) STUDY OF PHOTOCHROMIC MATERIALS FOR USE IN OPZfCAL SIGNAL PROCESSING 12. PERSONAL AUTHOR(S) Dr...the feasibility of using photochromic materials for programmable spatial filters and optical data storage/ applications. Write and erase times...Mercuay Dithizonate 35 V. General Experimental Behavior of Photochromic Materials 39 VI. Kinetics of the Relaxation Reaction 44 VII. Dependence of the

  8. Optical, Electrochemical and Thermal Studies of Conjugated Polymers Synthesized by Eutectic Melt Reaction.

    PubMed

    Bathula, Chinna; Buruga, Kezia; Kang, Youngjong; Khazi, Imtiyaz Ahmed M

    2017-05-01

    This paper reports on the synthesis of a novel donor-acceptor conjugated polymers, P1 and P2 by solvent free eutectic melt polymerization reaction. Triisopropylsilylethynyl(TIPS) substituted benzo[1,2-b:4,5-b']dithiophene(BDT) is used as donor, thienithiophene(TT) and thienopyrroledione(TPD) are utilized as acceptors for demonstrating eutectic polymerization. The most important fact in the solvent-free reaction between solid reactants actually proceeds through bulk liquid phases. Such liquid phases are possible due to the formation of eutectics between the reactants and product(s) and any evolution of heat. Naphthalene is explored in this reaction for forming eutectics with the reactants, resulting in desired polymers. Thermal stability, optical and electrochemical properties of these polymers were determined. Optical band gaps of the polymers were found to be 1.58 and 1.65 eV. Electrochemical studies by cyclic voltametry experiment revealed HOMO and LUMO energy levels to be -5.22, -5.60 eV, and -3.76, -4.16 eV, respectively. The polymers were thermally stable up to 285-400 °C. Thermal, optical and electrochemical studies indicated these materials to be promising candidates in organic electronic applications.

  9. Surface Response of Brominated Carbon Media on Laser and Thermal Excitation: Optical and Thermal Analysis Study

    NASA Astrophysics Data System (ADS)

    Multian, Volodymyr V.; Kinzerskyi, Fillip E.; Vakaliuk, Anna V.; Grishchenko, Liudmyla M.; Diyuk, Vitaliy E.; Boldyrieva, Olga Yu.; Kozhanov, Vadim O.; Mischanchuk, Oleksandr V.; Lisnyak, Vladyslav V.; Gayvoronsky, Volodymyr Ya.

    2017-02-01

    The present study is objected to develop an analytical remote optical diagnostics of the functionalized carbons surface. Carbon composites with up to 1 mmol g-1 of irreversibly adsorbed bromine were produced by the room temperature plasma treatment of an activated carbon fabric (ACF) derived from polyacrylonitrile textile. The brominated ACF (BrACF) was studied by elastic optical scattering indicatrix analysis at wavelength 532 nm. The obtained data were interpreted within results of the thermogravimetric analysis, X-ray photoelectron spectroscopy and temperature programmed desorption mass spectrometry. The bromination dramatically reduces the microporosity producing practically non-porous material, while the incorporated into the micropores bromine induces the dielectric and structural impact on surface polarizability and conductivity due to the charging effect. We have found that the elastic optical scattering in proper solid angles in the forward and the backward hemispheres is sensitive to the kind of the bromine bonding, e.g., physical adsorption or chemisorption, and the bromination level, respectively, that can be utilized for the express remote fabrication control of the nanoscale carbons with given interfaces.

  10. Studies of beam expansion and distributed Bragg reflector lasers for fiber optics and optical signal processing. Interim report

    SciTech Connect

    Garmire, E.M.

    1981-03-03

    Separate studies were performed on beam expansion and on Distributed Bragg Reflector (DBR) lasers preliminary to monolithic integration on GaAs substrates. These components are proposed for use in optical signal processing, for fiber optic sources and for high-brightness lasers.

  11. Sensitivity control of optical fiber biosensors utilizing turnaround point long period gratings with self-assembled polymer coatings

    NASA Astrophysics Data System (ADS)

    Gifford, Erika; Wang, Z.; Ramachandran, S.; Heflin, J. R.

    2007-09-01

    Ionic self-assembled multilayers (ISAMs) adsorbed on long period fiber gratings (LPGs) can serve as an inexpensive, robust, portable, biosensor platform. The ISAM technique is a layer-by-layer deposition technique that creates thin films on the nanoscale level. The combination of ISAMs with LPGs yields exceptional sensitivity of the optical fiber transmission spectrum. We have shown theoretically that the resonant wavelength shift for a thin-film coated LPG can be caused by the variation of the film's refractive index and/or the variation of the thickness of the film. We have experimentally demonstrated that the deposition of nm-thick ISAM films on LPGs induces shifts in the resonant wavelength of > 1.6 nm per nm of thin film. It has also been shown that the sensitivity of the LPG to the thickness of the ISAM film increases with increased film thickness. We have further demonstrated that ISAM-coated LPGs can function effectively as biosensors by using the biotin-streptavidin system and by using the Bacillus anthracis (Anthrax) antibody- PA (Protective Antigen) system. Experiments have been successfully performed in both air and solution, which illustrates the versatility of the biosensor. The results confirm that ISAM-LPGs yield a reusable, thermally-stable, and robust platform for designing and building efficient optical biosensors.

  12. All-optical single-sideband frequency upconversion utilizing the XPM effect in an SOA-MZI.

    PubMed

    Kim, Doo-Ho; Lee, Joo-Young; Choi, Hyung-June; Song, Jong-In

    2016-09-05

    An all-optical single sideband (OSSB) frequency upconverter based on the cross-phase modulation (XPM) effect is proposed and experimentally demonstrated to overcome the power fading problem caused by the chromatic dispersion of fiber in radio-over-fiber systems. The OSSB frequency upconverter consists of an arrayed waveguide grating (AWG) and a semiconductor optical amplifier Mach-Zehnder interferometer (SOA-MZI) and does not require an extra delay line used for phase noise compensation. The generated OSSB radio frequency (RF) signal transmitted over single-mode fibers up to 20 km shows a flat electrical RF power response as a function of the fiber length. The upconverted electrical RF signal at 48 GHz shows negligible degradation of the phase noise even without an extra delay line. The measured phase noise of the upconverted RF signal (48 GHz) is -74.72 dBc/Hz at an offset frequency of 10 kHz. The spurious free dynamic range (SFDR) measured by a two-tone test to estimate the linearity of the OSSB frequency upconverter is 72.5 dB·Hz2/3.

  13. Method of hybrid multiplexing for fiber-optic Fabry-Perot sensors utilizing frequency-shifted interferometry.

    PubMed

    Ou, Yiwen; Zhou, Ciming; Zheng, Angui; Cheng, Chunfu; Fan, Dian; Yin, Jiadi; Tian, Hui; Li, Mengmeng; Lu, Ying

    2014-12-10

    Experimental and theoretical research on hybrid multiplexing for fiber-optic Fabry-Perot (F-P) sensors based on frequency-shifted interferometry is presented. Four F-P sensors multiplexed in a hybrid configuration were experimentally investigated. The location of each multiplexed sensor was retrieved by performing the fast Fourier transform, and the reflection spectrum of each sensor was also obtained in spite of the spectral overlap, which was consistent with the results measured by an optical spectrum analyzer. With theoretical modeling, the maximum sensor number of a two-channel hybrid multiplexing system reaches 26 with crosstalk of less than -50  dB and a maximum frequency-domain signal-to-noise ratio (SNR) of ∼25  dB, when the source power is 2 mW and the sensor separation is optimal, i.e., 40 m. And the sensor number is almost twice that multiplexed by a serial system under the same conditions. An SNR improvement of 3.9 dB can be achieved by using a Hamming window in a noise-free system compared with a Hanning window. In addition, we applied the experimental multiplexing system to a strain sensing test. The cavity lengths and cavity-length shifts of the four F-P sensors were demodulated, which was consistent with the actual situation. It provides a new feasible method to multiplex F-P sensors at large scale.

  14. Wavelength-preserving polarization-insensitive all-optical 3R regenerator based on self- and cross-phase modulation and offset filtering utilizing Raman amplification

    NASA Astrophysics Data System (ADS)

    Chung, Sung Han

    Optical regeneration has the potential to significantly increase the reach of long-haul transmission systems. In this thesis, wavelength-preserving polarization-insensitive all-optical 3R regeneration is investigated and demonstrated for 10 and 40 Gb/s signals. The all-optical regenerator utilizes a self-pulsating laser for clock recovery, cross-phase modulation (XPM) based spectral broadening in a highly nonlinear fiber (HNLF) and offset filtering for retiming, and self-phase modulation based spectral broadening in a HNLF and offset filtering for reshaping. Raman amplification is used to increase the XPM-based spectral broadening and thus allow a design that meets the tradeoffs involved in simultaneously achieving good retiming and reshaping performance. The regenerator is shown to reduce amplitude noise and timing jitter while not causing a BER penalty. To fully validate the regeneration scheme, the cascadability is demonstrated using a recirculating loop. For a 10 Gb/s signal, with a regenerator spacing of 240 km, a return-to-zero, on-off-keyed (RZ-OOK) signal was transmitted over 18,000 km (75 loops) with a power penalty of 1.6 dB at a BER of 10 -9 compared to the back-to-back case. For a 40 Gb/s signal, with a regenerator spacing of 80 km, a RZ-OOK signal was transmitted over 8,000 km (100 loops) with a power penalty of 1.2 dB. In addition, all-optical 3R regeneration is demonstrated using a multimode quantum-dot Fabry Perot laser with ultra-low timing jitter.

  15. [A preliminary study on data mining techniques for utilizing the breast ultrasound database].

    PubMed

    Peng, Yulan; Zhang, Heqing; Jing, Jigang; Ma, Buyun; Lu, Xiao; Tang, Chong; Nie, Shan; Liu, Ying; Qin, Yuzhou; Luo, Yan

    2010-08-01

    Based on the breast ultrasound database of West China Hospital from January 1, 2002 to December 31, 2007, a study of data mining techniques for utilizing the diagnostic information of breast ultrasound and breast pathology was carried out. An innovative computerized retrieval system was invented. With the visual user interface of the system, the data of benignancy or malignancy diagnosed by ultrasound and pathologic examination, and the data on the diagnostic correlation of ultrasound and pathology were obtained, respectively. The qualities of data mining were 99. 98%-100%. By means of the retrieval system, the users can secure numerous data from the breast ultrasound database rapidly and accurately; so it contributes to the rational utilization of information from medical database for serving various medical studies. This method may also be helpful for doctors to utilize ultrasound database in other fields.

  16. Microscopic Studies of Quantum Phase Transitions in Optical Lattices

    NASA Astrophysics Data System (ADS)

    Bakr, Waseem S.

    2011-12-01

    In this thesis, I report on experiments that microscopically probe quantum phase transitions of ultracold atoms in optical lattices. We have developed a "quantum gas microscope" that allowed, for the first time, optical imaging and manipulation of single atoms in a quantum-degenerate gas on individual sites of an optical lattice. This system acts as a quantum simulator of strongly correlated materials, which are currently the subject of intense research because of the technological potential of high--T c superconductors and spintronic materials. We have used our microscope to study the superfluid to Mott insulator transition in bosons and a magnetic quantum phase transition in a spin system. In our microscopic study of the superfluid-insulator transition, we have characterized the on-site number statistics in a space- and time-resolved manner. We observed Mott insulators with fidelities as high as 99%, corresponding to entropies of 0.06kB per particle. We also measured local quantum dynamics and directly imaged the shell structure of the Mott insulator. I report on the first quantum magnetism experiments in optical lattices. We have realized a quantum Ising chain in a magnetic field, and observed a quantum phase transition between a paramagnet and antiferromagnet. We achieved strong spin interactions by encoding spins in excitations of a Mott insulator in a tilted lattice. We detected the transition by measuring the total magnetization of the system across the transition using in-situ measurements as well as the Neel ordering in the antiferromagnetic state using noise-correlation techniques. We characterized the dynamics of domain formation in the system. The spin mapping introduced opens up a new path to realizing more exotic states in optical lattices including spin liquids and quantum valence bond solids. As our system sizes become larger, simulating their physics on classical computers will require exponentially larger resources because of entanglement build

  17. Optical tweezers studies of transcription by eukaryotic RNA polymerases.

    PubMed

    Lisica, Ana; Grill, Stephan W

    2017-02-21

    Transcription is the first step in the expression of genetic information and it is carried out by large macromolecular enzymes called RNA polymerases. Transcription has been studied for many years and with a myriad of experimental techniques, ranging from bulk studies to high-resolution transcript sequencing. In this review, we emphasise the advantages of using single-molecule techniques, particularly optical tweezers, to study transcription dynamics. We give an overview of the latest results in the single-molecule transcription field, focusing on transcription by eukaryotic RNA polymerases. Finally, we evaluate recent quantitative models that describe the biophysics of RNA polymerase translocation and backtracking dynamics.

  18. Tractography of the optic radiation: a repeatability and reproducibility study.

    PubMed

    Dayan, Michael; Kreutzer, Sylvia; Clark, Chris A

    2015-04-01

    Our main objective was to evaluate the repeatability and reproducibility of optic radiation (OR) reconstruction from diffusion MRI (dMRI) data. 14 adults were scanned twice with the same 60-direction dMRI sequence. Peaks in the diffusion profile were estimated with the single tensor (ST), Q-ball (QSH) and persistent angular structure (PAS) methods. Segmentation of the OR was performed by two experimenters with probabilistic tractography based on a manually drawn region-of-interest (ROI) protocol typically employed for OR segmentation, with both standard and extended sets of ROIs. The repeatability and reproducibility were assessed by calculating the intra-class correlation coefficient (ICC) of intra- and inter-rater experiments, respectively. ICCs were calculated for commonly used dMRI metrics (FA, MD, AD, RD) and anatomical dimensions of the optic radiation (distance from Meyer's loop to the temporal pole, ML-TP), as well as the Dice similarity coefficient (DSC) between the raters' OR segmentation. Bland-Altman plots were also calculated to investigate bias and variability in the reproducibility measurements. The OR was successfully reconstructed in all subjects by both raters. The ICC was found to be in the good to excellent range for both repeatability and reproducibility of the dMRI metrics, DSC and ML-TP distance. The Bland-Altman plots did not show any apparent systematic bias for any quantities. Overall, higher ICC values were found for the multi-fiber methods, QSH and PAS, and for the standard set of ROIs. Considering the good to excellent repeatability and reproducibility of all the quantities investigated, these findings support the use of multi-fiber OR reconstruction with a limited number of manually drawn ROIs in clinical applications utilizing either OR microstructure characterization or OR dimensions, as is the case in neurosurgical planning for temporal lobectomy.

  19. An analytical study of thermal invariance of polymeric nanolayer gradient index optical components

    NASA Astrophysics Data System (ADS)

    Fein, Howard; Ponting, Michael

    2016-05-01

    Specially formulated Gradient-Index polymeric optical materials offer capabilities not possible in conventional GRIN or homogenous optics. A novel technology that enables large scale processing of nanolayered polymer films into real, performance-enhancing lenses and other optical components for Defense-related optical systems is currently being employed. Polymeric nanoLayer GRIN materials (LGRIN) offer the ability to design and fabricate optics with custom gradient refractive index profiles in optical components up to 90 mm in diameter and approaching 5 cm thick. High performance achromatic singlet lenses were designed using specially developed ZEMAX design tools and exceptionally high quality lenses were fabricated from the LGRIN materials. Optical performance of LGRIN optics is shown to be significantly better than with conventional monolithic optics while also significantly reducing optical system mass, volume, and optical element count. Understanding the thermal behavior of such optical components is essential to their operational capability. An experimental study of the effects of elevated operational environments to validate the feasibility of deploying LGRIN optics into real-world operational environments was carried out. Interferometric and physical measurements of structure and optical performance of LGRIN lenses was completed over a 30° - 50°C temperature range. It is shown that nanolayered LGRIN optics and components exhibit no significant variation in optical performance with temperature as compared with commercial, homogenous acrylic optics in the designed operational thermal range.

  20. Optical clearing of paper studied by optical coherence tomography: Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Kirillin, Mikhail; Priezzhev, Alexander V.; Hast, Jukka; Myllylä, Risto

    2006-02-01

    The problem of fast investigation of the structural properties of paper samples is of great interest nowadays. The existing methods for structural imaging of paper require long time for obtaining the final result or need changing the structure of the studied sample. One of modem high-promising non-invasive techniques for faster examination of paper structure is optical coherence tomography (OCT), based on the principles of low-coherence interferometry of light backscattered from the investigated object. In present paper we simulate OCT signals from different paper samples with planar and non-planar geometry of air-fiber boundaries implementing Monte Carlo method. OCT provides quality images of in-depth scanning for optically transparent low-scattering objects, however for high-scattering media the maximal scanning depth is quite small. In order to increase the scanning depth for such media different clearing agents are used. We consider ethanol, 1-pentanol, glycerol and benzyl alcohol as such agents applied to a paper sample. Obtained results show, that all agents under consideration provide better visualization of rear border of the studied sample, which is very important for precise paper thickness measurement. However, the agents, showing the best results for rear border visualization provide worse visualization of the inner structure of the sample.

  1. [Effectiveness of magnetotherapy in optic nerve atrophy. A preliminary study].

    PubMed

    Zobina, L V; Orlovskaia, L S; Sokov, S L; Sabaeva, G F; Kondé, L A; Iakovlev, A A

    1990-01-01

    Magnetotherapy effects on visual functions (vision acuity and field), on retinal bioelectric activity, on conductive vision system, and on intraocular circulation were studied in 88 patients (160 eyes) with optic nerve atrophy. A Soviet Polyus-1 low-frequency magnetotherapy apparatus was employed with magnetic induction of about 10 mT, exposure 7-10 min, 10-15 sessions per course. Vision acuity of patients with its low (below 0.04 diopters) values improved in 50 percent of cases. The number of patients with vision acuity of 0.2 diopters has increased from 46 before treatment to 75. Magnetotherapy improved ocular hemodynamics in patients with optic nerve atrophy, it reduced the time of stimulation conduction along the vision routes and stimulated the retinal ganglia cells. The maximal effect was achieved after 10 magnetotherapy sessions. A repeated course carried out in 6-8 months promoted a stabilization of the process.

  2. Structural and optical studies of CuO nanostructures

    SciTech Connect

    Chand, Prakash Gaur, Anurag Kumar, Ashavani

    2014-04-24

    In the present study, copper oxide (CuO) nanostructures have been synthesized at 140 °C for different aging periods, 1, 24, 48 and 96 hrs by hydrothermal method to investigate their effects on structural and optical properties. The X-ray diffractometer (XRD) pattern indicates the pure phase formation of CuO and the particle size, calculated from XRD data, has been found to be increasing from 21 to 36 nm for the samples synthesized at different aging periods. Field emission scanning electron microscope (FESEM) analysis also shows that the average diameter and length of these rectangular nano flakes increases with increasing the aging periods. Moreover Raman spectrums also confirm the phase formation of CuO. The optical band gaps calculated through UV-visible spectroscopy are found to be decreasing from 2.92 to 2.69 eV with increase in aging periods, 1 to 96 hrs, respectively.

  3. Optical and Hygroscopic Studies of Aerosols In Simulated Planetary Atmospheres

    NASA Astrophysics Data System (ADS)

    Hasenkopf, Christa A.

    2011-08-01

    Basic characteristics of the early Earth climate, the only known environment in the Universe in which life has been known to emerge and thrive, remain a mystery. In particular, little is understood about the Earth's atmosphere 2.8 billion years ago. From climate models and laboratory studies, it is postulated that an organic haze, much like that found on Saturn's largest moon Titan, covered the early Earth. This haze, generated from photolysis of carbon dioxide (CO2) and methane (CH4), may have had profound climatic consequences. Climate models of the early Earth that include this haze have had to rely upon optical properties of a Titan laboratory analog. Titan haze, though thought to be similar, is formed from a different combination of precursor gases and by different energy sources than early Earth haze. This thesis examines the direct and indirect radiative effects of aerosol on early Earth climate by studying the optical and hygroscopic properties of a laboratory analog. A Titan analog is studied for comparison and to better understand spacecraft-retrieved haze chemical and optical properties from Titan. The properties of the laboratory analogs, generated in a flowing reactor cell with a continuum ultraviolet (UV) light source, were primarily measured using cavity ringdown aerosol extinction spectroscopy and UV-visible (UV-Vis) transmission spectroscopy. We find that the optical properties of our early Earth analog are significantly different than those of the Titan analog from Khare et al. (1984). In both the UV and visible, when modeled as fractals, particles with the optical properties of the early Earth analog have approximately 30% larger extinction efficiencies than particles with Khare et al. (1984) values. This result implies our early Earth haze analog would provide a more efficient UV shield and have a stronger antigreenhouse effect than the Khare et al. (1984) Titan analog. Our Titan analog has significantly smaller imaginary refractive index values

  4. Study of surfaces using near infrared optical fiber spectrometry

    NASA Technical Reports Server (NTRS)

    Workman, G. L.; Arendale, W. A.; Hughes, C.

    1995-01-01

    The measurement and control of cleanliness for critical surfaces during manufacturing and in service provides a unique challenge for fulfillment of environmentally benign operations. Of particular interest has been work performed in maintaining quality in the production of bondline surfaces in propulsion systems and the identification of possible contaminants. This work requires an in-depth study of the possible sources of contamination, methodologies to identify contaminants, discrimination between contaminants and chemical species caused by environment, and the effect of particular contaminants on the bondline integrity of the critical surfaces. This presentation will provide an introduction to the use of optical fiber spectrometry in a nondestructive measurement system for process monitoring and how it can be used to help clarify issues concerning surface chemistry. Correlation of the Near Infrared (NIR) spectroscopic results with Optical Stimulated Electron Emission (OSEE) and ellipsometry will also be presented.

  5. Acousto-optics studied in polaritonic photonic crystals

    NASA Astrophysics Data System (ADS)

    Singh, Mahi R.; Racknor, C.

    2010-10-01

    We have studied the acousto-optic effect on the photon transmission and the spontaneous emission in polaritonic photonic crystal. We have considered that photonic crystals are fabricated from polaritonic materials such as GaP, MgO, LiNbO3 , and LiTaO3 . A two-level quantum dot is doped in a polaritonic crystal to study the decay rate of the spontaneous emission. The decay rate of quantum dots, band structure, and photon transmission coefficient have been calculated. It is found that band-gap width and the decay rate of quantum dots depends strongly on the high-frequency dielectric constant of the polaritonic crystals while the photonic band edges vary inversely by the ratio of longitudinal- to transverse-optical phonon energies. The spontaneous decay rate of the quantum dot can be controlled by the external strain field. This finding is significant because it is well known that the spontaneous emission is source of undesirable noise in different types of electronic and optical devices. Finally, we have also found the system can be switched from transmitting state to reflecting state by applying an external strain field. These are distinct and interesting results and can be used to fabricate new types of photonic couplers and fibers which in turn can be used to fabricate all photonic switches.

  6. Synthesis and quantum chemical studies of metalloorganics for electro-optical studies

    NASA Astrophysics Data System (ADS)

    Deepthi, S.; Jha, A.; Kumar, Ch. Ravi Shankar

    2017-07-01

    The dynamic nature of molecular materials are functional due to their nonlinear optical properties. Nonlinearity arising due to intermolecular interactions as self assembling phenomena between organic and metallic nanoparticles is of interest. The insight of this phenomena is attributed both by experimental and quantum chemical studies. Vibration studies performed by FTIR reveal intermolecular bonding forming metalloorganic POMZ with PAA and zinc oxide. These wave numbers were in agreement with theoretical studies performed by Gaussian 03v software package with B3LYP/6-31G basis set. Nonlinear optical properties such as energy difference, dipole moment, electronegativity, electrophylicity index and polarizability were attributed for electrical and optical properties of the material.

  7. Methods in pharmacoepidemiology: a review of statistical analyses and data reporting in pediatric drug utilization studies.

    PubMed

    Sequi, Marco; Campi, Rita; Clavenna, Antonio; Bonati, Maurizio

    2013-03-01

    To evaluate the quality of data reporting and statistical methods performed in drug utilization studies in the pediatric population. Drug utilization studies evaluating all drug prescriptions to children and adolescents published between January 1994 and December 2011 were retrieved and analyzed. For each study, information on measures of exposure/consumption, the covariates considered, descriptive and inferential analyses, statistical tests, and methods of data reporting was extracted. An overall quality score was created for each study using a 12-item checklist that took into account the presence of outcome measures, covariates of measures, descriptive measures, statistical tests, and graphical representation. A total of 22 studies were reviewed and analyzed. Of these, 20 studies reported at least one descriptive measure. The mean was the most commonly used measure (18 studies), but only five of these also reported the standard deviation. Statistical analyses were performed in 12 studies, with the chi-square test being the most commonly performed test. Graphs were presented in 14 papers. Sixteen papers reported the number of drug prescriptions and/or packages, and ten reported the prevalence of the drug prescription. The mean quality score was 8 (median 9). Only seven of the 22 studies received a score of ≥10, while four studies received a score of <6. Our findings document that only a few of the studies reviewed applied statistical methods and reported data in a satisfactory manner. We therefore conclude that the methodology of drug utilization studies needs to be improved.

  8. A Cross-Sectional Analytic Study of Postpartum Health Care Service Utilization in the Philippines

    PubMed Central

    Yamashita, Tadashi; Suplido, Sherri Ann; Ladines-Llave, Cecilia; Tanaka, Yuko; Senba, Naomi; Matsuo, Hiroya

    2014-01-01

    Background The maternal mortality ratio in the Philippines remains high; thus, it will be difficult to achieve the Millennium Development Goals 5 by 2015. Approximately two-thirds of all maternal deaths occur during the postpartum period. Therefore, we conducted the present study to examine the current state of postpartum health care service utilization in the Philippines, and identify challenges to accessing postpartum care. Methods A questionnaire and knowledge test were distributed to postpartum women in the Philippines. The questionnaire collected demographical characteristics and information about their utilization of health care services during pregnancy and the postpartum period. The knowledge test consisted of 11 questions regarding 6 topics related to possible physical and mental symptoms after delivery. Sixty-four questionnaires and knowledge tests were analyzed. Results The mean time of first postpartum health care visit was 5.1±5.2 days after delivery. Postpartum utilization of health care services was significantly correlated with delivery location (P<0.01). Women who delivered at home had a lower rate of postpartum health care service utilization than women who delivered at medical facilities. The majority of participants scored low on the knowledge test. Conclusion We found inadequate postpartum health care service utilization, especially for women who delivered at home. Our results also suggest that postpartum women lack knowledge about postpartum health concerns. In the Philippines, Barangay health workers may play a role in educating postpartum women regarding health care service utilization to improve their knowledge of possible concerns and their overall utilization of health care services. PMID:24465626

  9. Second- and third-order optical studies of 4-Bromoanilinium hydrogen phthalate single crystal for nonlinear optical device applications

    NASA Astrophysics Data System (ADS)

    Vivek, P.; Murugakoothan, P.

    2014-06-01

    A new organic NLO material 4-Bromoanilinium hydrogen phthalate was grown by slow evaporation technique. The solubility and metastable zone width were determined. The crystal belongs to monoclinic system with space group C2. Optical transmittance spectrum confirms the wide optical window. Absorption coefficient and band gap were calculated from transmittance. The thermal stability, laser-induced surface damage threshold and mechanical behaviour were analysed. The particle size-dependent second harmonic generation efficiency was evaluated by Kurtz-Perry powder method and existence of phase matching. The third-order optical study was measured by Z-scan studies. The dispersion of birefringence behaviour was studied.

  10. Using search engine query data to track pharmaceutical utilization: a study of statins.

    PubMed

    Schuster, Nathaniel M; Rogers, Mary A M; McMahon, Laurence F

    2010-08-01

    To examine temporal and geographic associations between Google queries for health information and healthcare utilization benchmarks. Retrospective longitudinal study. Using Google Trends and Google Insights for Search data, the search terms Lipitor (atorvastatin calcium; Pfizer, Ann Arbor, MI) and simvastatin were evaluated for change over time and for association with Lipitor revenues. The relationship between query data and community-based resource use per Medicare beneficiary was assessed for 35 US metropolitan areas. Google queries for Lipitor significantly decreased from January 2004 through June 2009 and queries for simvastatin significantly increased (P <.001 for both), particularly after Lipitor came off patent (P <.001 for change in slope). The mean number of Google queries for Lipitor correlated (r = 0.98) with the percentage change in Lipitor global revenues from 2004 to 2008 (P <.001). Query preference for Lipitor over simvastatin was positively associated (r = 0.40) with a community's use of Medicare services. For every 1% increase in utilization of Medicare services in a community, there was a 0.2-unit increase in the ratio of Lipitor queries to simvastatin queries in that community (P = .02). Specific search engine queries for medical information correlate with pharmaceutical revenue and with overall healthcare utilization in a community. This suggests that search query data can track community-wide characteristics in healthcare utilization and have the potential for informing payers and policy makers regarding trends in utilization.

  11. A critical period of brain development: studies of cerebral glucose utilization with PET.

    PubMed

    Chugani, H T

    1998-01-01

    Studies with positron emission tomography indicate that the human brain undergoes a period of postnatal maturation that is much more protracted than previously suspected. In the newborn, the highest degree of glucose metabolism (representative of functional activity) is in primary sensory and motor cortex, cingulate cortex, thalamus, brain stem, cerebellar vermis, and hippocampal region. At 2 to 3 months of age, glucose utilization increases in the parietal, temporal, and primary visual cortex; basal ganglia; and cerebellar hemispheres. Between 6 and 12 months, glucose utilization increases in frontal cortex. These metabolic changes correspond to the emergence of various behaviors during the first year of life. The measurement of absolute rates of glucose utilization during development indicates that the cerebral cortex undergoes a dynamic course of metabolic maturation that persists until ages 16-18 years. Initially, there is a rise in the rates of glucose utilization from birth until about age 4 years, at which time the child's cerebral cortex uses over twice as much glucose as that of adults. From age 4 to 10 years, these very high rates of glucose consumption are maintained, and only after then is there a gradual decline of glucose metabolic rates to reach adult values by age 16-18 years. Correlations between glucose utilization rates and synaptogenesis are discussed, and the argument is made that these findings have important implications with respect to human brain plasticity following injury as well as to "critical periods" of maximal learning capacity.

  12. Socioeconomic position as a determinant of maternal healthcare utilization: a population-based study in Namibia.

    PubMed

    Rashid, Mamunur; Antai, Diddy

    2014-01-01

    Improving maternal health is one of the eight Millennium Development Goals (MDGs) aimed at improving maternal healthcare and reducing maternal mortality. The utilization of maternal health services is influenced by several factors that need to be better understood. The objective of this study was to estimate the role of socio-economic position as a determinant of the utilization of maternal health care in Namibia. Data were collected from the Namibia Demographic and Health Survey in 2006-2007, based on survey responses from 9,804 female respondents aged 15-49 years. Multivariate logistic regression analysis was performed accounting for socio-economic factors associated with the use of maternal health care services. The results from both bivariate and multivariate analyses confirmed the importance of education, wealth index, place of residence and marital status in explaining the utilization of maternal health care services. Wealth index was the only consistently significant predictor of all indicators of maternal health services; with other factors being significantly associated with one or more of the indicators. Women's age and occupation showed inconclusive results in relation to access to maternal health care services. Several socio-economic factors significantly influence the three indicators of maternal health services utilization. Effective interventions need to take these factors into consideration and to explore means that increase maternal health service utilization especially among lowly educated and poor women in rural areas.

  13. Radiation or chemoradiation: initial utility study of selected therapy for local advanced stadium cervical cancer

    NASA Astrophysics Data System (ADS)

    Pramitasari, D. A.; Gondhowiardjo, S.; Nuranna, L.

    2017-08-01

    This study aimed to compare radiation only or chemo radiation treatment of local advanced cervical cancers by examining the initial response of tumors and acute side effects. An initial assessment employed value based medicine (VBM) by obtaining utility values for both types of therapy. The incidences of acute lower gastrointestinal, genitourinary, and hematology side effects in patients undergoing chemoradiation did not differ significantly from those undergoing radiation alone. Utility values for patients who underwent radiation alone were higher compared to those who underwent chemoradiation. It was concluded that the complete response of patients who underwent chemoradiation did not differ significantly from those who underwent radiation alone.

  14. Biomarker Utility Analysis Using an Exposure-PBPK/PD Model: A Carbaryl Case Study

    EPA Science Inventory

    There are two common biomarkers: markers of exposure and markers of health effects. The strength of the correlation between exposure or effect and a biomarker measurement determines the utility of a biomarker for assessing exposures or risks. In the current study, a linked expo...

  15. Climate Change Vulnerability Assessments: Four Case Studies of Water Utility Practices (2011 Final)

    EPA Science Inventory

    EPA has released the final report titled, Climate Change Vulnerability Assessments: Four Case Studies of Water Utility Practices. This report was prepared by the National Center for Environmental Assessment's Global Climate Research Staff in the Office of Research and D...

  16. Biomarker Utility Analysis Using an Exposure-PBPK/PD Model: A Carbaryl Case Study

    EPA Science Inventory

    There are two common biomarkers: markers of exposure and markers of health effects. The strength of the correlation between exposure or effect and a biomarker measurement determines the utility of a biomarker for assessing exposures or risks. In the current study, a linked expo...

  17. Creating Critical Conversations: Investigating the Utility of Socratic Dialogues in Elementary Social Studies Methods

    ERIC Educational Resources Information Center

    Buchanan, Lisa Brown

    2012-01-01

    This article explores the utility of Socratic dialogues in the elementary social studies methods course. Findings include preservice teachers' behaviors during dialogues, perceived strengths and challenges of using Socratic dialogues in teacher education, and the impact on student learning. Challenges and apprehensions encountered by the teacher…

  18. The Utilization of Retention Strategies at Church-Related Colleges: A Longitudinal Study

    ERIC Educational Resources Information Center

    Vander Schee, Brian Anthony

    2008-01-01

    Implementing effective student retention strategies is important for all institutions of higher education. This is especially true for smaller, private colleges as resources for higher education are stretched and the dependence on tuition revenue to maintain fiscal viability increases. This longitudinal study focuses on the utilization of…

  19. Climate Change Vulnerability Assessments: Four Case Studies of Water Utility Practices (2011 Final)

    EPA Science Inventory

    EPA has released the final report titled, Climate Change Vulnerability Assessments: Four Case Studies of Water Utility Practices. This report was prepared by the National Center for Environmental Assessment's Global Climate Research Staff in the Office of Research and D...

  20. Study of the Validity and Reliability of a Self-Efficacy Scale of Teaching Material Utilization

    ERIC Educational Resources Information Center

    Korkmaz, Ozgen

    2011-01-01

    The main purpose of this study is to develop a scale in order to detect the level of pre-service teachers' utilization from teaching materials based on their perception of self-efficacy. The sample group is composed of 439 students for the first application and 215 students for the second. In order to detect the validity of the scale, exploratory…