Science.gov

Sample records for study utilizing optical

  1. Study of Utilizing Static Photoelastic Effect in Integrated Optical Devices

    NASA Astrophysics Data System (ADS)

    Tang, Zhi-Cheng

    Channel waveguides have been produced in LiNbO _3, LiTaO_3, BaTiO_3, and BSTN ferroelectric crystals by depositing thick SiO_2 films at an elevated temperature and patterning them by combination of reactive ion etching and wet etching. Propagation losses of 0.8 dB/cm and 0.9 dB/cm for TE- and TM- polarization, respectively, were achieved for LiNbO_3 at 0.633 μm wavelength, while insertion losses of 8.4 dB and 3.3 dB for TE- and TM-polarization, respectively, were obtained for a waveguide in z-cut BSTN of 5 mm in length at 1.3 mu m wavelength. Electrooptic modulations have been demonstrated for LiNbO_3 using coplanar electrodes and for BSTN using both coplanar and vertical electrodes. Tunable guided-wave TErightarrow TM mode converters with 98% efficiency have been obtained using a periodic, strain inducing SiO _2 film on a zinc indiffused LiTaO _3 waveguide. The conversion is highly wavelength selective, with a spectral width of 9 nm in a device with interactive length of 5.4 mm. Thermal and electro-optic tuning of the center wavelength were demonstrated. A polarization -independent electrooptically tunable wavelength filter using passive polarization splitters and strain-induced polarization mode couplers in LiTaO_3 has also been realized. Tuning of the center wavelength from 655 nm to 692 nm was demonstrated. An optical bandwidth (FWHM) of 11 nm and a tuning rate of 0.4 nm/v were obtained.

  2. Theoretical Study of Surface Plasmon Resonance-based Fiber Optic Sensor Utilizing Cobalt and Nickel Films

    NASA Astrophysics Data System (ADS)

    Shukla, Sarika; Sharma, Navneet K.; Sajal, Vivek

    2016-06-01

    A surface plasmon resonance (SPR) based fiber optic sensor with cobalt (Co) and nickel (Ni) layers (one layer at a time) is theoretically analyzed. The sensitivity of sensor increases linearly with increase in refractive index of sensing medium for all thicknesses of Co and Ni layers. Besides it, SPR sensor with Co layer has been shown to demonstrate higher sensitivity than that of Ni layer. The usage of Co in place of noble metals (such as gold and silver) curtails the cost of SPR sensor. Optimized thicknesses of Co and Ni layers are found to be 80 nm and 60 nm, respectively.

  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. 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

  5. Fiber optic transmissions in electrical utility applications

    NASA Astrophysics Data System (ADS)

    Lamarche, Louis

    2000-12-01

    The application of optic and photonic technology in electric networks in many cases is subject to constraints that differ from telecommunication or commercial applications. Starting by an overview of the quality of service (QoS) needed, in the first part of this paper we summarise some issues that confronted Hydro-Quebec in applying fibre optic technologies to its network. We explore by presenting lab and field trials some issues related to optical ground wires (OPGW) design and network architecture. We present temperature, vibration, ageing and short circuit current effects. We submit the results and analysis of a first field trial of and OC-48 link over a 265 km OPGW line, PMD measurements and an overview of the final design that is being implemented presently using Raman amplification. In the last section of the paper, we will discuss shortly of non-conventional photonic based technologies, local and distributed sensors and optical phenomenon that are used or have been discovered in utilities optical networks.

  6. 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.

  7. Naturalistic Study of Evaluation Utilization.

    ERIC Educational Resources Information Center

    Alkin, Marvin C.

    1980-01-01

    Case studies of educational program evaluations demonstrate that utilization of evaluative information occurs; however, its forms and the forces influencing utilization are complex. Naturalistic methods were used to study utilization. (See RIE: ED 174 666). (Available from: Jossey-Bass, Inc., 433 California St., San Francisco, CA 94104, single…

  8. 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

  9. Optical temperature sensor utilizing birefringent crystals

    NASA Technical Reports Server (NTRS)

    Quick, William H. (Inventor); James, Kenneth A. (Inventor); Strahan, Virgil H. (Inventor)

    1980-01-01

    A temperature sensor comprising an optical transducer member having an array of birefringent crystals. The length and, accordingly, the sensitivity to temperature change of successive birefringent crystals varies according to a particular relationship. The transducer is interconnected with a fiber optic transmission and detecting system. Respective optical output signals that are transmitted from the birefringent crystals via the fiber optic transmission system are detected and decoded so as to correspond to digits of a numbering system, whereby an accurate digital representation of temperature can ultimately be provided.

  10. 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.

  11. 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.

  12. Optical fiber networks boost utilities` power to thrive

    SciTech Connect

    McDonald, M.; Boxer, M.

    1997-07-01

    Recent legislative and regulatory initiatives have propelled the electric power industry onto the information superhighway. Utility companies are not only becoming large users of the information superhighway, but they also are building the physical network to carry the traffic. Some utilities are implementing fiber-optic projects that match or even exceed the size, scope and capabilities of networks installed by telecommunications firms and cable-television companies. Current optical-fiber deployments range from hundreds or thousands of route miles planned or installed by large utilities-such as Entergy and The Southern Company-to networks of just a few route miles envisioned by many smaller municipalities.

  13. Toward Nanometer-Scale Optical Photolithography: Utilizing the Near-Field of Bowtie Optical Nanoantennas

    PubMed Central

    Sundaramurthy, Arvind; Kino, Gordon S.; Schuck, P. James; Conley, Nicholas R.; Fromm, David P.; Moerner, W. E.

    2006-01-01

    Optically resonant metallic bowtie nanoantennas are utilized as fabrication tools for the first time, resulting in the production of polymer resist nanostructures <30 nm in diameter at record low incident multiphoton energy densities. The nanofabrication is accomplished via nonlinear photopolymerization, which is initiated by the enhanced, confined optical fields surrounding the nanoantenna. The position, size, and shape of the resist nanostructures directly correlate with rigorous finite-difference time-domain computations of the field distribution, providing a nanometer-scale measurement of the actual field confinement offered by single optical nanoantennas. In addition, the size of the photoresist regions yields strong upper bounds on photoacid diffusion and resist resolution in SU-8, demonstrating a technique that can be generalized to the study of many current and yet-to-be-developed photoresist systems. PMID:16522022

  14. 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…

  15. Development and utilization of optical low coherence reflectometry for the study of multiple scattering in randomly distributed solid-liquid suspensions

    NASA Astrophysics Data System (ADS)

    Randall, Summer Lockerbie

    The investigation of Optical Low Coherence Reflectometry (OLCR) for evaluation of highly scattering suspensions involves a balance between the observation of real systems and theoretical development. The main focus of this work was the development and utilization of OLCR to investigate highly scattering solid-liquid suspensions over a wide range of particle sizes, using monodispersed, bimodal, and polydispersed polystyrene nanosphere suspensions and Department of Energy (DOE) waste surrogates. The results were the first experimental demonstration that coherent optical backscattering from media with randomly distributed spherical nanoparticles is dominated by Mie resonances. Industrial process samples of various sizes and dispersity were also measured to expand the applicability of OLCR to a wide range of process needs. Current research has focused on the deconvolution of sample parameters from the tailing decay profiles of highly scattering matrices. Significant progress has been made on data analysis methods for monodispersed and more complex compositions of polystyrene suspensions and these methods have been applied to HLW surrogate suspensions and several industrial models. The research described within this dissertation has implications for measurement needs on basic science, industrial, and national laboratory levels. The scope of this research includes advancements in both fundamental understanding of multiple scattering through analysis of model systems and in development and application of the technology to current measurement needs within industry.

  16. 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.

  17. 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.

  18. Fiber fault location utilizing traffic signal in optical network.

    PubMed

    Zhao, Tong; Wang, Anbang; Wang, Yuncai; Zhang, Mingjiang; Chang, Xiaoming; Xiong, Lijuan; Hao, Yi

    2013-10-01

    We propose and experimentally demonstrate a method for fault location in optical communication network. This method utilizes the traffic signal transmitted across the network as probe signal, and then locates the fault by correlation technique. Compared with conventional techniques, our method has a simple structure and low operation expenditure, because no additional device is used, such as light source, modulator and signal generator. The correlation detection in this method overcomes the tradeoff between spatial resolution and measurement range in pulse ranging technique. Moreover, signal extraction process can improve the location result considerably. Experimental results show that we achieve a spatial resolution of 8 cm and detection range of over 23 km with -8-dBm mean launched power in optical network based on synchronous digital hierarchy protocols. PMID:24104308

  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. Clinical Utility of Optical Coherence Tomography in Glaucoma.

    PubMed

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

    2016-07-01

    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

  1. Development of on-fiber optical sensors utilizing chromogenic materials

    NASA Astrophysics Data System (ADS)

    Yuan, Jianming; El-Sherif, Mahmoud A.

    1999-01-01

    On-fiber optical sensors, designed with chromogenic materials used as the fiber modified cladding, were developed for sensing environmental conditions. The design was based on the previously developed on-fiber devices. It is known that the light propagation characteristics in optical fibers are strongly influenced by the refractive index of the cladding materials. Thus, the idea of the on- fiber devices is based on replacing the passive optical fiber cladding with active or sensitive materials. For example, temperature sensors can be developed by replacing the fiber clad material with thermochromic materials. In this paper, segmented polyurethane-diacetylene copolymer (SPU), was selected as the thermochromic material for temperature sensors applications. This material has unique chromogenic properties as well as the required mechanical behaviors. During UV exposure and heat treatment, the color of the SPU copolymer varies with its refractive index. The boundary condition between core and cladding changes due to the change of the refractive index of the modified cladding material. The method used for the sensor development presented involves three steps: (a) removing the fiber jacket and cladding from a small region, (b) coating the chromogenic materials onto the modified region, and (c) integrating the optical fiber sensor components. The experimental set-up was established to detect the changes of the output signal based on the temperature variations. For the sensor evaluation, real-time measurements were performed under different heating-cooling cycles. Abrupt irreversible changes of the sensor output power were detected during the first heating-cooling cycle. At the same time, color changes of the SPU copolymer were observed in the modified region of the optical fiber. For the next heating-cooling cycles, however, the observed changes were almost completely reversible. This result demonstrates that a low-temperature sensor can be built by utilizing the

  2. TWRS LDUA utilization study report

    SciTech Connect

    Rieck, R.H.

    1994-09-01

    Tank Waste Remediation Systems functional requirements were reviewed. The Light Duty Utility Arm capabilities were considered as a means to support completion of these functional requirements. The recommendation is made to continue to develop the LDUA, integrating TWRS functional needs into the design to better support completion of TWRS mission needs.

  3. 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.

  4. 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;…

  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. Utility energy storage applications studies

    SciTech Connect

    Schoenung, S.M.; Burns, C.

    1996-09-01

    The values of benefits and costs have been estimated for applying energy storage to three situations on the Niagara Mohawk Power Corporation system. One situation is a valuable industrial customer requiring high quality, reliable power. The second situation is the need for reliable power at the end of a radial distribution feeder. The third situation is a case of thermal overload on a transmission line to a growing load in an environmentally sensitive location. The first case requires a small storage system (30 MJ); the second and third require relatively large systems (250 and 550 MWh, respectively). A variety of energy storage technologies was considered for each case. This paper presents the benefit/cost results for the technologies considered for each case. The technologies compared in this study are superconducting magnetics energy storage, batteries, flywheels, capacitors, compressed air energy storage, compressed air in vessels, and pumped hydro storage.

  7. 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

  8. 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.

  9. 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.

  10. The Economic Utility of Foreign Language Study.

    ERIC Educational Resources Information Center

    Grosse, Christine Uber; Tuman, Walter Vladimir; Critz, Mary Anne

    1998-01-01

    A study measured the economic utility of language study for 84 graduate students in international management by comparing their reasons for language study with several major economic indicators, including corporate job opportunities. The study, though limited in scope, yields insights into the real and perceived costs and benefits of language…

  11. 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…

  12. 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.

  13. 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.

  14. 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

  15. AIDS COST AND SERVICE UTILIZATION STUDY (ACSUS)

    EPA Science Inventory

    The AIDS Cost and Services Utilization Survey (ACSUS) was a longitudinal study of persons with HIV-related disease. In a combination of personal interviews and abstraction of medical and billing records spanning an 18-month period, information was collected on more than 1,900 HIV...

  16. HIV COST AND SERVICES UTILIZATION STUDY (HCSUS)

    EPA Science Inventory

    The HIV Cost and Services Utilization Study (HCSUS) is the first major research effort to collect information on a nationally representative sample of people in care for HIV infection. HCSUS is funded through a cooperative agreement between the Agency for Health Care Policy Resea...

  17. 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…

  18. 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.

  19. 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

  20. Ultrastable reference frequency distribution utilizing a fiber optic link

    NASA Technical Reports Server (NTRS)

    Calhoun, Malcolm; Kuhnle, Paul

    1993-01-01

    The Frequency Standards Laboratory at the Jet Propulsion Laboratory (JPL) is responsible for the generation and distribution of ultra-stable reference frequency in NASA's Deep Space Network (DSN). Certain assemblies and components of the Radio Science and VLBI systems are located in the cones of tracking antennas hundreds of meters from the Frequency and Timing Subsystem's frequency standards. The very stringent requirements of these users challenge the performance of state-of-the-art frequency sources as well as the associated signal distribution system. The reference frequency distribution system described is designed around a low temperature coefficient of delay (TCD) optical fiber. On-site measurements of the fiber optic link alone indicate 100 MHz phase noise performance on the order of -120 dBc at 1 Hz from the carrier and Allan deviation on the order of parts in 10(exp 16) at 1000 seconds averaging time. The measured phase noise and stability of the link indicate that the performance characteristics of the hydrogen maser frequency standards are not degraded by the distribution system. Thus, optical fibers and electro-optic devices as distribution media appear to be a viable alternative to the classical coaxial cable distribution systems.

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

    PubMed

    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

  2. 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.

  3. 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.

  4. Study on communications costs for Columbus utilization

    NASA Astrophysics Data System (ADS)

    Nielsen, Svend Moller; Sorensen, Nicolaj

    1988-09-01

    On the basis of a hypothetical communications scenario established for cost calculations, the expected communications costs for Columbus utilization in the year 1995 and onwards to the year 2025, are estimated to provide initial considerations for a charging policy in relation to potential Columbus users. A hypothetical sample of five European countries is established, and current telecommunications tariffs for the data, voice, and video communications required for the Columbus utilization in and between these five countries and the USA are identified. Technological, political, and commercial development trends are analyzed as to their likely influences on future telecommunications tariff development. Communications costs for the study period are estimated, assuming telecommunications administrations to be providers of service and considering estimated equipment and operations costs. Alternative communications solutions are indicated.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Nonlinear optical studies of surfaces

    NASA Astrophysics Data System (ADS)

    Shen, Y. R.

    1994-07-01

    The possibility 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.

  12. 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.

  13. External electro-optic sampling utilizing a poled polymer asymmetric Fabry Perot cavity as an electro-optical probe tip

    NASA Astrophysics Data System (ADS)

    Chen, Kaixin; Zhang, Hongbo; Zhang, Daming; Yang, Han; Yi, Maobin

    2002-09-01

    External electro-optic sampling utilizing a poled polymer asymmetry Fabry-Perot cavity as electro-optic probe tip has been demonstrated. Electro-optical polymer spin coated on the high-reflectivity mirror (HRM) was corona poled. Thus, an asymmetric F-P cavity was formed based on the different reflectivity of the polymer and HRM and it converted the phase modulation that originates from electro-optic effect of the poled polymer to amplitude modulation, so only one laser beam is needed in this system. The principle of the sampling was analyzed by multiple reflection and index ellipsoid methods. A 1.2 GHz microwave signal propagating on coplanar waveguide transmission line was sampled, and the voltage sensitivity about 0.5 mV/ Hz was obtained.

  14. 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.

  15. 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

  16. All-optical frequency upconversion of a quasi optical single sideband signal utilizing a nonlinear semiconductor optical amplifier for radio-over-fiber applications.

    PubMed

    Park, Minho; Song, Jong-In

    2011-11-21

    An all-optical frequency upconversion technique using a quasi optical single sideband (q-OSSB) signal in a nonlinear semiconductor optical amplifier (NSOA) for radio-over-fiber applications is proposed and experimentally demonstrated. An optical radio frequency signal (f(RF) = 37.5 GHz) in the form of a q-OSSB signal is generated by mixing an optical intermediate frequency (IF) signal (f(IF) = 2.5 GHz) with an optical local oscillator signal (f(LO) = 35 GHz) utilizing coherent population oscillation and cross gain modulation effects in an NSOA. The phase noise, conversion efficiency, spurious free dynamic range (SFDR), and transmission characteristics of the q-OSSB signal are investigated. PMID:22109476

  17. 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…

  18. 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.

  19. 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.

  20. Microwave-Photonic Frequency Multiplication Utilizing Optical Four-Wave Mixing and Fiber Bragg Gratings

    NASA Astrophysics Data System (ADS)

    Wiberg, Andreas; Pérez-Millán, Pere; Andrés, Miguel V.; Hedekvist, Per Olof

    2006-01-01

    A novel technique for optical multiplication of a millimeter-wave carrier is presented. It utilizes optical four-wave mixing (FWM) in a highly nonlinear fiber (HNLF) and the filtering properties of matched fiber Bragg gratings (FBGs). The technique includes a sixfold electrical frequency multiplication in the optical domain. In this experiment, the multiplicator is driven electronically at 6.67 GHz, and the created millimeter wave has a frequency of 40 GHz. The generated carrier has a linewidth lower than 3 Hz and a carrier to noise ratio exceeding 50 dB. Furthermore, successful data transmission over the optical fiber of 2.5 Gb/s on the generated millimeter-wave carrier was performed.

  1. Optical tweezers to study viruses.

    PubMed

    Arias-Gonzalez, J Ricardo

    2013-01-01

    A virus is a complex molecular machine that propagates by channeling its genetic information from cell to cell. Unlike macroscopic engines, it operates in a nanoscopic world under continuous thermal agitation. Viruses have developed efficient passive and active strategies to pack and release nucleic acids. Some aspects of the dynamic behavior of viruses and their substrates can be studied using structural and biochemical techniques. Recently, physical techniques have been applied to dynamic studies of viruses in which their intrinsic mechanical activity can be measured directly. Optical tweezers are a technology that can be used to measure the force, torque and strain produced by molecular motors, as a function of time and at the single-molecule level. Thanks to this technique, some bacteriophages are now known to be powerful nanomachines; they exert force in the piconewton range and their motors work in a highly coordinated fashion for packaging the viral nucleic acid genome. Nucleic acids, whose elasticity and condensation behavior are inherently coupled to the viral packaging mechanisms, are also amenable to examination with optical tweezers. In this chapter, we provide a comprehensive analysis of this laser-based tool, its combination with imaging methods and its application to the study of viruses and viral molecules. PMID:23737055

  2. 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.

  3. 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. PMID:21725475

  4. 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

  5. Optical Telescope Design Study Results

    NASA Astrophysics Data System (ADS)

    Livas, J.; Sankar, S.

    2015-05-01

    We report on the results of a study conducted from Nov 2012-Apr 2013 to develop a telescope design for a space-based gravitational wave detector. The telescope is needed for efficient power delivery but since it is directly in the beam path, the design is driven by the requirements for the overall displacement sensitivity of the gravitational wave observatory. Two requirements in particular, optical pathlength stability and scattered light performance, are beyond the usual specifications for good image quality encountered in traditional telescopic systems. An important element of the study was to tap industrial expertise to develop an optimized design that can be reliably manufactured. Key engineering and design trade-offs and the sometimes surprising results will be presented.

  6. Magneto-optical and photoemission studies of ultrathin wedges

    SciTech Connect

    Bader, S.D.; Li, Dongqi

    1995-12-01

    Magnetic phase transitions of Fe wedges grown epitaxially on Cu(100) are detected via the surface magneto-optical Kerr effect and used to construct a phase diagram for face centered Fe. Also, the confinement of Cu sp- and d-quantum-well states is studied for Cu/Co(wedge)/Cu(100) utilizing undulator-based photoemission experiments.

  7. 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.

  8. 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.

  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. Study on comprehensive utilization of secondary resources

    SciTech Connect

    Lihua, G.; Ruilu, L.

    1995-12-31

    In light of the properties on process mineralogy of the old tailings in a certain copper mine in the People`s Republic of China, a new process of combined reagent and stepwise flotation is applied in which the flotation of copper sulfides is followed by the flotation of copper oxides. Recoveries of copper and associated gold and silver have been greatly increased. The tailings obtained were subjected to the gravitational separation-magnetic separation process to recover iron minerals. Tailings from iron separation are taken as fillers and sent to the pit underground. Thus, the secondary resources are comprehensively utilized.

  11. Development of an imaging modality utilizing 2D optical signals during an EPI-fluorescent optical mapping experiment

    NASA Astrophysics Data System (ADS)

    Prior, Phillip; Roth, Bradley J.

    2009-05-01

    Optical mapping is a commonly used technique to visualize the electrical activity in the heart. Recently, several groups have attempted to use the signals acquired in optical mapping to image the transmembrane potential in the heart, which would be particularly advantageous when studying the effects of defibrillation-type shocks throughout the wall of the heart. Our work presents an alternative imaging method that makes use of data obtained using multiple wavelengths and therefore multiple optical decay constants. A modified form of the diffusion equation Green's function for a semi-infinite slab of tissue is derived and used to relate the detected optical signals to the source of emission photons. Images using the optical signals are reconstructed using Gaussian quadrature and matrix inversion. Our results show that images can be obtained for source terms located below the tissue surface. Furthermore, we demonstrate that our reconstruction method's susceptibility to noise can be alleviated using sophisticated matrix inverse techniques, such as singular value decomposition. Sources that rapidly decay with depth or are highly localized in the image plane require more sophisticated techniques (e.g., regularization methods) to image the electrical activity in the heart. The work presented here demonstrates the feasibility of a new imaging technique of cardiac electrical activity using optical mapping.

  12. 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.

  13. Blood optical clearing studied by optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Zhernovaya, Olga; Tuchin, Valery V.; Leahy, Martin J.

    2013-02-01

    The main limitation of optical imaging techniques for studying biological tissues is light scattering leading to decreasing of transmittance, which lowers the imaging quality. In this case, an immersion method for optical clearing of biological tissues can provide a possible solution to this problem, because the application of biocompatible clearing agents can reduce light scattering. Optical clearing represents a promising approach to increasing the imaging depth for various techniques, for example, various spectroscopy and fluorescent methods, and optical coherence tomography (OCT). We investigate the improvement of light penetration depth in blood after application of polyethylene glycol, polypropylene glycol, propylene glycol, and hemoglobin solutions using an OCT system. Influence of clearing agents on light transport in tissues and blood was also investigated in the mouse tail vein.

  14. 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. PMID:25936046

  15. 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.

  16. 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.

  17. 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.

  18. An adaptive optics approach for laser beam correction in turbulence utilizing a modified plenoptic camera

    NASA Astrophysics Data System (ADS)

    Ko, Jonathan; Wu, Chensheng; Davis, Christopher C.

    2015-09-01

    Adaptive optics has been widely used in the field of astronomy to correct for atmospheric turbulence while viewing images of celestial bodies. The slightly distorted incoming wavefronts are typically sensed with a Shack-Hartmann sensor and then corrected with a deformable mirror. Although this approach has proven to be effective for astronomical purposes, a new approach must be developed when correcting for the deep turbulence experienced in ground to ground based optical systems. We propose the use of a modified plenoptic camera as a wavefront sensor capable of accurately representing an incoming wavefront that has been significantly distorted by strong turbulence conditions (C2n <10-13 m- 2/3). An intelligent correction algorithm can then be developed to reconstruct the perturbed wavefront and use this information to drive a deformable mirror capable of correcting the major distortions. After the large distortions have been corrected, a secondary mode utilizing more traditional adaptive optics algorithms can take over to fine tune the wavefront correction. This two-stage algorithm can find use in free space optical communication systems, in directed energy applications, as well as for image correction purposes.

  19. Sequentially timed all-optical mapping photography (STAMP) utilizing spectral filtering.

    PubMed

    Suzuki, Takakazu; Isa, Fumihiro; Fujii, Leo; Hirosawa, Kenichi; Nakagawa, Keiichi; Goda, Keisuke; Sakuma, Ichiro; Kannari, Fumihiko

    2015-11-16

    We propose and experimentally demonstrate a new method called SF-STAMP for sequentially timed all-optical mapping photography (STAMP) that utilizes spectral filtering. SF-STAMP is composed of a diffractive optical element (DOE), a band-pass filter, and two Fourier transform lenses. Using a linearly frequency-chirped pulse and converting the wavelength to the time axis, we realize single-shot ultrafast burst imaging. As an experimental demonstration of SF-STAMP, we monitor the dynamics of a laser ablation using a linearly frequency-chirped broadband pulse (>100 nm) that is temporally stretched up to ~40 ps. This imaging method is expected to be effective for investigating ultrafast dynamics in a diverse range of fields, such as photochemistry, plasma physics, and fluidics. PMID:26698529

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. Environmental Radiation Studies Utilizing RadNet

    NASA Astrophysics Data System (ADS)

    Jackson, Steven

    2010-03-01

    RadNet is an Environmental Protection Agency (EPA) managed environmental radiation and air quality monitoring station that has been recently installed on the Angelo State University campus. RadNet cycles air through a filter which collects particulate matter for an examination of alpha and beta activities of contained material. This project includes defining dominant alpha and beta emitters in the local environment, conducting a correlation study involving the effect of weather and wind direction on filter activity, physical interpretation of air quality index (AQI), and the use of X-ray fluorescence to verify radon decay progeny in the local environment.

  5. 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.

  6. Crystal optical studies of lithium tetraborate

    NASA Astrophysics Data System (ADS)

    Kushnir, O. S.; Burak, Y. V.; Bevz, O. A.; Polovinko, I. I.

    1999-10-01

    Using the HAUP-type universal polarimeter and the Senarmont technique, detailed crystal optical studies of Li2B4O7, lithium tetraborate, are carried out. It is shown that the optical indicatrix rotation and the optical activity are absent from the crystal, in accordance with symmetry considerations. Measurements of optical birefringence reveal the existence of a regular staircase-like temperature behaviour in the whole range under investigation (290-480 K), a hysteresis character of the birefringence under cycling temperature and a pronounced thermooptical memory effect. The origins of the above phenomena are analysed, in particular the possible influence of the pyroelectric effect and systematic errors of the optical equipment. A conclusion is drawn that the main features of the birefringence are well explained by an incommensurately modulated super-structure which is at present a matter of debate. The peculiarities of the optical properties of lithium tetraborate are compared with those of incommensurate crystals known from the literature.

  7. Methanol optic neuropathy: a histopathological study.

    PubMed

    Sharpe, J A; Hostovsky, M; Bilbao, J M; Rewcastle, N B

    1982-10-01

    The histopathologic effects of methanol on the optic nerve were studied in four patients. Circumscribed myelin damage occurred behind the lamina cribrosa in each nerve. Axons were preserved. Demyelination also occurred in cerebral hemispheric white matter in one patient. This selective myelinoclastic effect of methanol metabolism is probably caused by histotoxic anoxia in watershed areas of the cerebral and distal optic nerve circulations. Juxtabulbar demyelination may cause optic disk edema in methanol poisoning by compressive obstruction of orthograde axoplasmic flow. Visual loss may be due to disruption of saltatory conduction. Retrolaminar demyelinating optic neuropathy is an early morphologic correlate of visual loss in methanol intoxication. PMID:6889696

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. Nonlinear Optical Studies of Bacteriorhodopsin

    NASA Astrophysics Data System (ADS)

    Rao, D. V. G. L. N.; Aranda, F. J.; Chen, Z.; Akkara, J. A.; Kaplan, D. L.; Nakashima, M.

    We report interesting results on nonlinear optics at low powers in bacteriorhodopsin films with applications in all-optical switching and modulation. Chemically stabilized films of bacteriorhodopsin in a polymer matrix for which the lifetime of the excited M state is 3 to 4 orders of magnitude longer than that of water solutions of wild-type bR were used in these experiments. Due to the sensitivity of the films, very small powers of order microwatts are required for optical phase conjugation. The influence of the fast photochemical M to B transition induced by blue light on the saturation intensity, phase conjugate intensity and switching time was established. We also report our measurements of the intensity dependence of the self-focusing and self-defocusing properties of wild-type bR in water solution using the Z-scan technique with low power cw lasers at two wavelengths on either side of the absorption band. Our measurements indicate that the sign of the nonlinearity depends on the wavelength and the magnitude depends on the fluence of the incident laser beam. The observed self-focusing and defocusing is not due to the intrinsic electronic nonlinearity. The observations can be explained in terms of the Kramers-Kronig dispersion relation that relates the real and imaginary parts of the complex index of refraction.

  13. Optical characterization in laser damage studies

    NASA Astrophysics Data System (ADS)

    Commandré, Mireille; Natoli, Jean Yves; Gallais, Laurent; Wagner, Frank; Amra, Claude

    2007-01-01

    The development of high power lasers and optical micro-components requires optical characterization techniques for studying behavior of optical materials under illumination, laser damage phenomena and ageing. More usual optical characterization tools are based on measurements of absorption, scattering and luminescence; they are non destructive evaluation techniques. It is important to combine several tools which allow getting complementary information. Optical tools can be used in damage initiation studies or to characterize properties of damaged areas. Because defects involved in laser damage initiation are sub-micrometer sized, both high spatial resolution and high sensitivity are required to detect defects as small as possible. Furthermore optical tools have to be implemented in damage set-up and at the same wavelength for a detailed analysis of damage mechanisms. We present an overview of recent developments in the field of optical characterization in connection with laser damage. Especially, a high resolution photothermal deflection microscopy has been coupled with a damage set-up to detect nano-absorbing precursors of damage and to study their behavior under irradiation. Thus model defects such as gold inclusions of various sizes have been followed through irradiation and results are compared with numerical simulations. Optical characterization allows to get determining information if several techniques are associated with numerical simulations.

  14. 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.

  15. RETROSPECTIVE EPIDEMIOLOGICAL STUDY OF DISEASE ASSOCIATED WITH WASTEWATER UTILIZATION

    EPA Science Inventory

    A retrospective epidemiological study was carried out on the association between enteric disease incidence and wastewater utilization in 79 kibbutzim (cooperative agricultural settlements) in Israel having a population of 32,672. Medical records on disease incidence were collecte...

  16. 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. PMID:22453476

  17. Fourier-domain optical coherence tomography: recent advances toward clinical utility

    PubMed Central

    Bouma, Brett E; Yun, Seok-Hyun; Vakoc, Benjamin J; Suter, Melissa J; Tearney, Guillermo J

    2009-01-01

    With the advent of Fourier-domain techniques, optical coherence tomography (OCT) has advanced from high-resolution ‘point’ imaging over small fields-of-view to comprehensive microscopic imaging over three-dimensional volumes that are comparable to the dimensions of luminal internal organs. This advance has required the development of new lasers, improved spectrometers, minimally invasive catheters and endoscopes, and novel optical and signal processing strategies. In recent cardiovascular, ophthalmic, and gastrointestinal clinical studies, the capabilities of Fourier-domain OCT have enabled a new paradigm for diagnostic screening of large tissue areas, which addresses the shortcomings of existing technologies and focal biopsy. PMID:19264475

  18. NMR and optical studies of piezoelectric polymers

    SciTech Connect

    Schmidt, V.H.; Tuthill, G.F.

    1993-01-01

    Progress is reported in several areas dealing with piezoelectric (electroactive) polymers (mostly vinylidene fluoride, trifluoroethylene, copolymers, PVF[sub 2]) and liquid crystals. Optical studies, neutron scattering, NMR, thermal, theory and modeling were done.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. 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. PMID:27370436

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Limitations to the performance of nonlinear optical processes utilizing atomic vapors

    SciTech Connect

    Kauranen, M.O.

    1992-01-01

    Performance characteristics of nonlinear wave-mixing processes that utilize atomic vapors as the nonlinear medium are investigated experimentally and theoretically for the case of optical phase conjugation and for the process of noise control of optical beams. A theory of the polarization properties of phase conjugation by two-photon-resonant four-wave mixing is developed. The theory includes the effects of saturation of the two-photon transition by the pump waves. For the case of an S [yields] S two photon transition, the vector character of the phase conjugation process is found to be degraded by the transfer of population from the ground state to the two-photon-excited state and by the Stark shift of two-photon resonance frequency. The case of circular and counterrotating polarizations is predicted to lead to perfect polarization conjugation for any value of total pump intensity as long as the intensities of the two pump waves are equal. The predictions of the theory are tested using the 3S [yields] 4S two-photon transition of sodium. The polarization-conjugation property of the interaction is limited to a phase-conjugate reflectivity of the order of 1% by the grating-washout effects. The interaction of a weak probe wave with a strong degenerate pump wave in a one-photon-resonant atomic vapor is found to give rise to increased fluctuations in the intensity of the probe wave as measured with a spectrum analyzer. The increased fluctuations result from the large two-beam-coupling gain experienced by the vacuum sidebands of the probe wave. This mechanism limits the amount of quantum-noise reduction that can be achieved by schemes utilizing four-wave-mixing in atomic vapors.

  7. Nonlinear optical studies of a novel pyrazoline

    NASA Astrophysics Data System (ADS)

    Janardhana, K.; Ravindrachary, V.; Kumar, P. C. Rajesh; Umesh, G.; Manjunatha, K. B.; Ismayil

    2012-06-01

    A novel pyrazoline, 3-(phenyl)-5-(4-hydroxyphenyl)-1-(2, 4-dinitrophenyl)-2-pyrazoline (PHDP) was synthesized using standard method and its chemical structure was confirmed using FTIR studies. The linear and non linear optical properties of the compound were studied using UV-Vis and Z-scan techniques. UV-Vis spectrum shows that the compound is transparent in the visible region and absorption in the UV region. The z-scan study shows that the compound possesses third and higher order optical nonlinearity. The calculated optical absorption cross sections indicate that the operating nonlinear mechanism is reverse saturable absorption type. The real part of the third-order nonlinear optical susceptibility χ3 was estimated and the closed aperture data shows that PHDP possess negative nonlinearity.

  8. 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.

  9. 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

  10. Novel finding of optic nerve central T2 hypointensity utilizing 3 Tesla MR imaging.

    PubMed

    Riascos, Roy; Heymann, John C; Hakimelahi, Reza; Hasan, Khader; Sargsyan, Ashot; Barr, Yael R; Tom, James; Alperin, Noam; Kramer, Larry A

    2015-04-01

    We sought to report a central T2 hypointensity within the optic nerve on 3 T MRI studies obtained as part of the NASA Flight Medicine Visual Impairment Intracranial Pressure Protocol that had not been described previously. Twenty-one astronauts, who had undergone MRI of both orbits with direct coronal T2 sequences between 2010 and 2012, were retrospectively included. Two of the astronauts did not have previous exposure to microgravity at the time of their scans. A central T2 hypointensity was observed in 100% of both right and left eyes. It was completely visualized throughout the nerve course in 15 right eyes (71.4%) and in 19 left eyes (90.5%).We describe a new finding seen in all study participants: a central T2 hypointensity in the epicenter of the optic nerve. We speculate that this T2 hypointensity may represent flow voids caused by the central retinal vessels. PMID:25923682

  11. Novel finding of optic nerve central T2 hypointensity utilizing 3 Tesla MR imaging

    PubMed Central

    Heymann, John C; Hakimelahi, Reza; Hasan, Khader; Sargsyan, Ashot; Barr, Yael R; Tom, James; Alperin, Noam; Kramer, Larry A

    2015-01-01

    We sought to report a central T2 hypointensity within the optic nerve on 3 T MRI studies obtained as part of the NASA Flight Medicine Visual Impairment Intracranial Pressure Protocol that had not been described previously. Twenty-one astronauts, who had undergone MRI of both orbits with direct coronal T2 sequences between 2010 and 2012, were retrospectively included. Two of the astronauts did not have previous exposure to microgravity at the time of their scans. A central T2 hypointensity was observed in 100% of both right and left eyes. It was completely visualized throughout the nerve course in 15 right eyes (71.4%) and in 19 left eyes (90.5%).We describe a new finding seen in all study participants: a central T2 hypointensity in the epicenter of the optic nerve. We speculate that this T2 hypointensity may represent flow voids caused by the central retinal vessels. PMID:25923682

  12. Advances in optical imaging for pharmacological studies

    PubMed Central

    Arranz, Alicia; Ripoll, Jorge

    2015-01-01

    Imaging approaches are an essential tool for following up over time representative parameters of in vivo models, providing useful information in pharmacological studies. Main advantages of optical imaging approaches compared to other imaging methods are their safety, straight-forward use and cost-effectiveness. A main drawback, however, is having to deal with the presence of high scattering and high absorption in living tissues. Depending on how these issues are addressed, three different modalities can be differentiated: planar imaging (including fluorescence and bioluminescence in vivo imaging), optical tomography, and optoacoustic approaches. In this review we describe the latest advances in optical in vivo imaging with pharmacological applications, with special focus on the development of new optical imaging probes in order to overcome the strong absorption introduced by different tissue components, especially hemoglobin, and the development of multimodal imaging systems in order to overcome the resolution limitations imposed by scattering. PMID:26441646

  13. 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.

  14. 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.

  15. 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.

  16. Optical manipulation for single-cell studies.

    PubMed

    Ramser, Kerstin; Hanstorp, Dag

    2010-04-01

    In the last decade optical manipulation has evolved from a field of interest for physicists to a versatile tool widely used within life sciences. This has been made possible in particular due to the development of a large variety of imaging techniques that allow detailed information to be gained from investigations of single cells. The use of multiple optical traps has high potential within single-cell analysis since parallel measurements provide good statistics. Multifunctional optical tweezers are, for instance, used to study cell heterogeneity in an ensemble, and force measurements are used to investigate the mechanical properties of individual cells. Investigations of molecular motors and forces on the single-molecule level have led to discoveries that would have been difficult to make with other techniques. Optical manipulation has prospects within the field of cell signalling and tissue engineering. When combined with microfluidic systems the chemical environment of cells can be precisely controlled. Hence the influence of pH, salt concentration, drugs and temperature can be investigated in real time. Fast advancing technical developments of automated and user-friendly optical manipulation tools and cross-disciplinary collaboration will contribute to the routinely use of optical manipulation techniques within the life sciences. PMID:19718682

  17. 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.

  18. 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.

  19. 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.

  20. 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. PMID:27272077

  1. STS/Spacelab payload utilization planning study: Executive summary

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The planning process recommended to meet the orbital flight requirements for the Space Transportation System and payload development, procurement, operations, and support leading to authorization and funding of STS and payload project activities is described. The rationale and rp primary products of STS utilization planning are summarized along with the implementation of the system. Major recommendations of the study are included.

  2. Hospital utilization after a telemonitoring program: a pilot study.

    PubMed

    White-Williams, Cynthia; Unruh, Lynn; Ward, Kendall

    2015-01-01

    The long-term effects of remote monitoring on hospital utilization and health care costs are understudied in home health care. The researchers performed a retrospective study, in a hospital-based home health care agency, to consider the effects of remote monitoring in 326 patients with heart failure 90 days after discharge from services. While statistical significance was not noted, clinical significance suggests that there was a decreased hospital utilization rate and decreased average cost per hospitalization in the remote monitoring group. PMID:25517540

  3. 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.

  4. 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.

  5. 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…

  6. Nonlinear optical studies of polymer interfaces

    SciTech Connect

    Shen, Y.R. |

    1993-11-01

    Second-order nonlinear optical processes can be used as effective surface probes. They can provide some unique opportunities for studies of polymer interfaces. Here the author describes two examples to illustrate the potential of the techniques. One is on the formation of metal/polymer interfaces. The other is on the alignment of liquid crystal films by mechanically rubbed polymer surfaces.

  7. Study of optimum methods of optical communication

    NASA Technical Reports Server (NTRS)

    Harger, R. O.

    1972-01-01

    Optimum methods of optical communication accounting for the effects of the turbulent atmosphere and quantum mechanics, both by the semi-classical method and the full-fledged quantum theoretical model are described. A concerted effort to apply the techniques of communication theory to the novel problems of optical communication by a careful study of realistic models and their statistical descriptions, the finding of appropriate optimum structures and the calculation of their performance and, insofar as possible, comparing them to conventional and other suboptimal systems are discussed. In this unified way the bounds on performance and the structure of optimum communication systems for transmission of information, imaging, tracking, and estimation can be determined for optical channels.

  8. An all-optical frequency up-converter utilizing four-wave mixing in a semiconductor optical amplifier for sub-carrier multiplexed radio-over-fiber applications.

    PubMed

    Kim, Hyoung-Jun; Song, Jong-In; Song, Ho-Jin

    2007-03-19

    A novel all-optical frequency up-converter utilizing four-wave mixing (FWM) in a semiconductor optical amplifier (SOA) was proposed and experimentally demonstrated. The frequency up-converter converted an optical intermediate frequency (IF) signal (f(IF) = 2.5 GHz) to an optical radio frequency (RF) signal (f(RF) = 35 and 40 GHz) through mixing with an optical local oscillator (LO) signal (f(LO) = 37.5 GHz). The up-converter showed positive conversion efficiency of 5.77 dB for the optical IF power of -22 dBm and the optical LO power of -13 dBm. This scheme showed broad bandwidths with respect to both LO and IF frequencies. The up-converter showed a phase noise of -84.5 dBc/Hz for the LO frequency of 37.5 GHz (f(LO)) and the offset frequency of 10 kHz after the frequency up-conversion. PMID:19532579

  9. [Study on mercury re-emissions during fly ash utilization].

    PubMed

    Meng, Yang; Wang, Shu-Xiao

    2012-09-01

    The amount of fly ash produced during coal combustion is around 400 million tons per year in China. About 65%-68% of fly ash is used in building material production, road construction, architecture and agriculture. Some of these utilization processes include high temperature procedures, which may lead to mercury re-emissions. In this study, experiments were designed to simulate the key process in cement production and steam-cured brick production. A temperature programmed desorption (TPD) method was used to study the mercury transformation in the major utilization processes. Mercury re-emission during the fly ash utilization in China was estimated based on the experimental results. It was found that mercury existed as HgCl2 (Hg2 Cl2), HgS and HgO in the fly ash. During the cement production process, more than 98% of the mercury in fly ash was re-emitted. In the steam-curing brick manufacturing process, the average mercury re-emission percentage was about 28%, which was dominated by the percentage of HgCl2 (Hg2 Cl2). It is estimated that the mercury re-emission during the fly ash utilization have increased from 4.07 t in 2002 to 9.18 t in 2008, of which cement industry contributes about 96.6%. PMID:23243850

  10. Lasers and space optical systems study

    NASA Astrophysics Data System (ADS)

    Giuliano, Concetto; Annaballi, Angela L.

    1998-01-01

    The Air Force and other government organizations have considered the application of space-based lasers since the early 1970s. Recent studies have identified the enormous potential of lasers and optical systems in space to support the Full-Spectrum Dominance envisioned by the Joint Chiefs of Staff in ``Joint Vision 2010.'' The Air Force Research Laboratory has undertaken the LAsers and S_pace O_ptical S_ystems (LASSOS) Study to examine in detail how space lasers and optics (defined as any laser system based in space or any terrestrial-based laser whose beam transits space) could best be used to satisfy this critical need. This twelve-month study will identify promising technology concepts for space laser/optic systems, develop system concepts based on these technologies with special emphasis on systems capable of performing multiple missions, assess how well these systems can accomplish operational tasks in a quantitative manner, and design technology development roadmaps for selected concepts. Since work on the study had commenced only days before the publication deadline, this manuscript is necessarily limited to a description of the background, motivation, and organization of the study. The ``Concept Definition'' phase of the study is scheduled to be completed by the time of the STAIF conference. By that time, study participants will have identified key concepts that best satisfy criteria for timely and cost-effective augmentation of combat capability. A final report, which will be made available to authorized recipients, will be written after completion of the study in August 1998.

  11. Study on the improvement of overall optical image quality via digital image processing

    NASA Astrophysics Data System (ADS)

    Tsai, Cheng-Mu; Fang, Yi Chin; Lin, Yu Chin

    2008-12-01

    This paper studies the effects of improving overall optical image quality via Digital Image Processing (DIP) and compares the promoted optical image with the non-processed optical image. Seen from the optical system, the improvement of image quality has a great influence on chromatic aberration and monochromatic aberration. However, overall image capture systems-such as cellphones and digital cameras-include not only the basic optical system but also many other factors, such as the electronic circuit system, transducer system, and so forth, whose quality can directly affect the image quality of the whole picture. Therefore, in this thesis Digital Image Processing technology is utilized to improve the overall image. It is shown via experiments that system modulation transfer function (MTF) based on the proposed DIP technology and applied to a comparatively bad optical system can be comparable to, even possibly superior to, the system MTF derived from a good optical system.

  12. 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.

  13. 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.

  14. Stability studies of Solar Optical Telescope dynamics

    NASA Technical Reports Server (NTRS)

    Gullapalli, Sarma N.; Pal, Parimal K.; Ruthven, Gregory P.

    1987-01-01

    The Solar Optical Telescope (SOT) is designed to operate as an attached payload mounted on the Instrument Pointing System (IPS) in the cargo bay of the Shuttle Orbiter. Pointing and control of SOT is accomplished by an active Articulated Primary Mirror (APM), an active Tertiary Mirror (TM), an elaborate set of optical sensors, electromechanical actuators and programmable controllers. The structural interactions of this complex control system are significant factors in the stability of the SOT. The preliminary stability study results of the SOT dynamical system are presented. Structural transfer functions obtained from the NASTRAN model of the structure were used. These studies apply to a single degree of freedom (elevation). Fully integrated model studies will be conducted in the future.

  15. 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. PMID:12105703

  16. 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.

  17. Utilizing nonlinear optical microscopy to investigate the development of early cancer in nude mice in vivo

    NASA Astrophysics Data System (ADS)

    Wang, Chun-Chin; Li, Feng-Chieh; Lin, Sung-Jan; Lo, Wen; Dong, Chen-Yuan

    2007-07-01

    In this investigation, we used in vivo nonlinear optical microscopy to image normal and carcinogen DMBA treated skin tissues of nude mice. We acquired two-photon autofluroescence and second harmonic generation (SHG) images of the skin tissue, and applied the ASI (Autofluorescence versus SHG Index) to the resulting image. This allows us to visualize and quantify the interaction between mouse skin cells and the surrounding connective tissue. We found that as the imaging depth increases, ASI has a different distribution in the normal and the treated skin tissues. Since the DMBA treated skin eventually became squamous cell carcinoma (SCC), our results show that the physiological changes to mouse skin en route to become cancer can be effectively tracked by multiphoton microscopy. We envision this approach to be effective in studying tumor biology and tumor treatment procedures.

  18. Utilization of Mueller matrix formalism to obtain optical targets depolarization and polarization properties

    NASA Astrophysics Data System (ADS)

    Le Roy-Brehonnet, F.; Le Jeune, B.

    Polarization is an important property of several physical phenomena such as Rayleigh and Raman ( High intensity Raman Interactions: A. Penzkofer, A. Lauberteau, and W. Kaiser, Progress in Quantum Electronics, 6) (1982) scattering ( Multi-photon Scattering Molecular Spectroscopy, S. Kielich, Progress in Optics, E. Wolf(ed.) North-Holland, Amsterdam) (1983) or fluorescence ( Principles of Fluorescence Spectroscopy, J.R. Lakowicz, Plenum Press) (1986) for example, but also for laser spectral lines ( Laser Lines in Atomic Species, C. S. Willett, Progress in Quantum Electronics, 1) (1969). So, the polarimetric aspect for the propagation in media, such as fibres (Recent progress in fibre optics, G. Cancellieri, F. Chiaraluce, Progress in Quantum Electronics, 18) (1994), the atmosphere and the sea ( Light Scattering by Small Particles (Dover, New York, 1981), must be considered. Following general considerations on the different polarimetric formalisms(Chapter I), this paper first presents a review of present theoretical works on the exploitation of the Mueller matrix (Chapter II). This is followed by original studies of our own, concerning the possibility of extracting polarizing and depolarizing properties of a target characterized by a Mueller matrix (Chapter III). We then study the depolarization effects induced by targets in the Poincare´space (Chapter IV). This depolarization is induced by multiple reflections on rough surfaces or due to partial volume scattering. We have developed an algorithm, based on the knowledge of experimental noise, to classify experimental Mueller matrices according to their polarimetric characteristics. The laser imaging set-up used is described and the method (such as dichroic and birefringent ferrofluid samples) and surfaces (such as sand and other natural targets, dielectric or metallic rough targets).

  19. 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.

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

    PubMed

    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

    2010-10-01

    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. PMID:21033960

  1. Tumor Functional and Molecular Imaging Utilizing Ultrasound and Ultrasound-Mediated Optical Techniques

    PubMed Central

    Yuan, Baohong; Rychak, Joshua

    2014-01-01

    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. PMID:23219728

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Controlling and utilizing optical forces at the nanoscale with plasmonic antennas

    NASA Astrophysics Data System (ADS)

    Lovera, Andrea; Martin, Olivier J. F.

    2011-10-01

    Plasmonic dipole antennas are powerful optical devices for many applications since they combine a high field enhancement with outstanding tunability of their resonance frequency. The field enhancement, which is mainly localized inside the nanogap between both arms, is strong enough to generate attractive forces for trapping extremely small objects flowing nearby. Furthermore it dramatically enhances their Raman scattering cross-section generating SERS emission. In this publication, we demonstrate how plasmonic antennas provide unique means for bringing analyte directly into hotspots by merely controlling the optical force generated by the plasmon resonance. This technique is very suitable for immobilizing objects smaller that the diffraction limit and requires a very little power density. In this work, 20nm gold nanoparticles functionalized with Rhodamine 6G are trapped in the gap of nanoantennas fabricated with e-beam lithography on glass substrate. The entire system is integrated into a microfluidic chip with valves and pumps for driving the analyte. The field enhancement is generated by a near-IR laser (λ=808nm) that provides the trapping energy. It is focused on the sample through a total internal reflection (TIRF) objective in dark field configuration with a white light source. The scattered light is collected through the same objective and the spectrum of one single antenna spectrum is recorded and analyzed every second. A trapping event is characterized by a sudden red-shift of the antenna resonance. This way, it is possible to detect the trapping of extremely small objects. The SERS signal produced by a trapped analyte can then be studied by switching from the white light source to a second laser for Raman spectroscopy, while keeping the trapping laser on. The trapping and detection limit of this approach will be discussed in detail.

  7. Magneto-optic studies of magnetic oxides

    NASA Astrophysics Data System (ADS)

    Gehring, Gillian A.; Alshammari, Marzook S.; Score, David S.; Neal, James R.; Mokhtari, Abbas; Fox, A. Mark

    2012-10-01

    A brief review of the use of magneto-optic methods to study magnetic oxides is given. A simple method to obtain the magnetic circular dichroism (MCD) of a thin film on a transparent substrate is described. The method takes full account of multiple reflections in the film and substrate. Examples of the magneto-optic spectra of Co-doped ZnO, Fe3O4, and GdMnO3 are given. The Maxwell-Garnett method is used to describe the effects of metallic cobalt inclusions in Co:ZnO samples, and the change of the MCD spectra of Fe3O4 at the Verwey temperature is discussed. Data showing different MCD signals at different energies is presented for GdMnO3.

  8. Low-coherence interferometric sensor system utilizing an integrated optics configuration

    NASA Astrophysics Data System (ADS)

    Plissi, M. V.; Rogers, A. J.; Brassington, D. J.; Wilson, M. G. F.

    1995-08-01

    The implementation of a twin Mach-Zehnder reference interferometer in an integrated optics substrate is described. From measurements of the fringe visibilities, an identification of the fringe order is attempted as a way to provide an absolute sensor for any parameter capable of modifying the difference in path length between two interfering optical paths.

  9. 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.

  10. Online Photolytic Optical Gating of Caged Fluorophores in Capillary Zone Electrophoresis Utilizing an Ultraviolet-Light Emitting Diode

    PubMed Central

    Gallagher, Elyssia S.; Comi, Troy J.; Braun, Kevin L.; Aspinwall, Craig A.

    2013-01-01

    Photolytic optical gating (POG) facilitates rapid, on-line and highly sensitive analyses, though POG utilizes UV lasers for sample injection. We present a lower-cost, more portable alternative, employing an ultraviolet (UV)-LED array to inject caged fluorescent dyes via photolysis. Utilizing the UV-LED array, labeled amino acids were injected with nanomolar limits of detection (270 ± 30 nM and 250 ± 30 nM for arginine and citrulline, respectively). When normalized for the difference in light intensity, the UV-LED array provides comparable sensitivity to POG utilizing UV lasers. Additionally, the UV-LED array yielded sufficient beam quality and stability to facilitate coupling with Hadamard transformation, resulting in increased sensitivity. This work shows, for the first time, the use of a UV-LED for online POG with comparable sensitivity to conventional laser sources but for lower cost. PMID:22911376

  11. The utility of body size indices derived from optical plankton counter data for the characterization of marine zooplankton assemblages

    NASA Astrophysics Data System (ADS)

    Krupica, Karla L.; Sprules, W. Gary; Herman, Alex W.

    2012-03-01

    To evaluate the utility of size-based indices derived from an Optical Plankton Counter (OPC) through detection of spatial and temporal trends in zooplankton biomass, zooplankton size data were collected with an OPC across the Scotian Shelf region of the northwest Atlantic Ocean in April and October of 1997, 1998, and 1999. Eight size-based indices were computed - three simple size metrics (arithmetic mean, geometric mean, coefficient of variation) and metrics derived from the Normalized Biomass Size Spectrum (NBSS; X- and Y-coordinates and curvature of a fitted quadratic function) and the Pareto distribution (Y-intercept and slope). Results indicate that the simple size indices and those derived from the Pareto distribution consistently accounted for the greatest portion of annual variation in zooplankton biomass whereas indices derived from the NBSS accounted only for some secondary patterns. Simple indices also accounted for the greatest portion of spatial variance in zooplankton biomass whereas the NBSS and Pareto accounted for secondary patterns. Patterns in zooplankton communities based on these indices reflected broad taxonomic trends and were related to independent observations on atmospheric and hydrographic conditions in the study area. Size-based zooplankton data from continuous survey instruments can provide powerful adjuncts to both freshwater and marine aquatic monitoring.

  12. A novel approach to all-optical wavelength conversion by utilizing a reflective semiconductor optical amplifier in a co-propagation scheme

    NASA Astrophysics Data System (ADS)

    Guo, L. Q.; Connelly, M. J.

    2008-09-01

    Nonlinear optical gain modulation in an InGaAsP/InP bulk reflective semiconductor optical amplifier (RSOA) is studied. The differences of the optical properties between RSOAs and conventional SOAs are initially investigated. All-optical wavelength conversion based on nonlinear gain modulation in RSOAs is demonstrated at a bit rate of 2.488 Gbit/s. It is shown that a bit-error-rate of <10-9 can be achieved and an extinction ratio of >9 dB can be obtained at a bit rate of 2.488 Gbit/s with a 231-1 non-return-to-zero (NRZ) pseudorandom bit sequence (PRBS). In comparison with conventional SOAs, wavelength conversion by RSOAs shows much improved performances in high-speed all-optical wavelength conversions.

  13. Guided care: cost and utilization outcomes in a pilot study.

    PubMed

    Sylvia, Martha L; Griswold, Michael; Dunbar, Linda; Boyd, Cynthia M; Park, Margaret; Boult, Chad

    2008-02-01

    Guided Care (GC) is an enhancement to primary care that incorporates the operative principles of disease management and chronic care innovations. In a 6-month quasi-experimental study, we compared the cost and utilization patterns of patients assigned to GC and Usual Care (UC). The setting was a community-based general internal medicine practice. The participants were patients of 4 general internists. They were older, chronically ill, community-dwelling patients, members of a capitated health plan, and identified as high risk. Using the Adjusted Clinical Groups Predictive Model (ACG-PM), we identified those at highest risk of future health care utilization. We selected the 75 highest-risk older patients of 2 internists at a primary care practice to receive GC and the 75 highest-risk older patients of 2 other internists in the same practice to receive UC. Insurance data were used to describe the groups' demographics, chronic conditions, insurance expenditures, and utilization. Among our results, at baseline, the GC (all targeted patients) and UC groups were similar in demographics and prevalence of chronic conditions, but the GC group had a higher mean ACG-PM risk score (0.34 vs. 0.20, p < 0.0001). During the following 6 months, the GC group had lower unadjusted mean insurance expenditures, hospital admissions, hospital days, and emergency department visits (p > 0.05). There were larger differences in insurance expenditures between the GC and UC groups at lower risk levels (at ACG-PM = 0.10, mean difference = $4340; at ACG-PM = 0.6, mean difference = $1304). Thirty-one of the 75 patients assigned to receive GC actually enrolled in the intervention. These results suggest that GC may reduce insurance expenditures for high-risk older adults. If these results are confirmed in larger, randomized studies, GC may help to increase the efficiency of health care for the aging American population. PMID:18279112

  14. 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.

  15. 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.

  16. Theoretical and experimental study of fiber-optic fluorescence immunosensors

    NASA Astrophysics Data System (ADS)

    Cao, He

    This dissertation investigates the optical detection of antigens (in this case, food pathogens such as Salmonella) with fiber-optic immunosensors. The major techniques used for this optical detection include: (1)Linking the antigens to some physical tracers that can be optically detected; (2)Collecting and transmitting the optical signal to an optical detector. From an optical point of view, the problem is a nonimaging-optics problem to collect a fluorescent signal from an extended Lambertian source and deliver it to an optical detection system with maximum energy transfer and distinct wavelength separation. A raytrace model of the optical detection system was used for numerical simulations to analyze and optimize the optical design. The result leads to an improvement of the optical detection. Related physical problems such as magnetic focusing effect, fluorescence detection, and wavelength separation have also been studied in detail. With the adoption of a single-step immunomagnetic assay, experimental studies have been conducted for the detection of Salmonella, with a dual- fiber optical probe and tapered tubular waveguide probes. The test results have shown that the detection system gives detection limit of approximately 106 CFU/ml with dual-fiber optical probes, and 105 CFU/ml with improved tubular waveguide probes. The system developed for this research project is designed as a cost-effective portable instrument that may be used for field-testing. Rapid and on-site detection, low cost instrumentation and a reusable optical probe have been emphasized throughout the study.

  17. An affordable optically stimulated luminescent dosimeter reader utilizing multiple excitation wavelengths.

    PubMed

    Kearfott, Kimberlee J; West, W Geoffrey

    2015-10-01

    A lower-cost optically stimulated luminescence (OSL) reader with increased flexibility for pursuing laboratory research into OSL theory and application was designed and constructed. This was achieved by using off-the-shelf optical components and higher-power light emitting diodes. The resulting reader includes more wavelengths of excitation light than current commercial readers, as well as the ability to swap out filters and other components during an experiment. PMID:26142807

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. The Architecture and Utility of SeaBASS: the SeaWiFS Bio-optical Archive and Storage System

    NASA Astrophysics Data System (ADS)

    Werdell, P.; Bailey, S. W.; Fargion, G.; McClain, C.

    2001-12-01

    The accumulation and evaluation of in situ data is a critical aspect of both satellite ocean color sensor validation and algorithm development. NASA's Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and Sensor Intercomparison and Merger for Biological and Oceanic Studies (SIMBIOS) Projects designed the SeaWiFS Bio-optical Archive and Storage System (SeaBASS) to be a local repository of radiometric, phytoplankton pigment, and other oceanographic and atmospheric data, collected using well-defined and consistent measurement protocols. These data have been used by the SIMBIOS Project to validate SeaWiFS, Ocean Color and Temperature Scanner (OCTS), and Modular Optoelectronic Scanner (MOS) data products, to develop and evaluate bio-optical algorithms used to generate such products, for data merger studies, and to characterize the calibration history and stability of the field instruments used to build validation data sets. Data archived in SeaBASS were collected using a number of instrument packages on a variety of different platforms. The archive consists of an organized directory structure where physical data files and documentation are stored and a relational database system for managing and controlling these data and metadata. A series of World Wide Web-based search engines provide the user community direct access to data files, metadata, and geophysical data products. Additionally, other online utilities are available for generating maps and plots of data archived in SeaBASS. Historically, to protect the publication rights of contributors' data and to limit user-support to active participants, access to SeaBASS has been limited to contributing researchers and to members of the SIMBIOS and other NASA-affiliated Science Teams. As of August 2001, however, data collected prior to December 31, 1999 are available to the public at large. These data are available online and via the National Oceanographic Data Center. This report elaborates on the architecture of SeaBASS and

  6. In vivo optical interferometric imaging of human skin utilizing monochromatic light source.

    PubMed

    Osawa, Kentaro; Minemura, Hiroyuki; Anzai, Yumiko; Tomita, Daisuke; Shimanaka, Tetsuya; Suzuki, Tomokazu; Iida, Hiroki; Matsuura, Naoya; Katagiri, Chika; Yamashita, Toyonobu; Hara, Yusuke; Watanabe, Koichi

    2016-07-01

    We have demonstrated tomographic imaging of in vivo human skin with an optical interferometric imaging technique using a monochromatic light source. The axial resolution of this method is determined by the center wavelength and the NA of the objective and is irrelevant to the bandwidth of the light source in contrast to optical coherence tomography. Our imaging system is constructed with low-priced and small-sized compact disk optical pickup components, a laser diode, a high NA objective, and a voice coil actuator. In spite of its low cost and small size, our imaging system can visualize the structure of human skin as clearly as a commercial reflectance confocal microscope. PMID:27409189

  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. 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. PMID:20216852

  9. Coherent anti-Stokes Raman spectroscopy utilizing phase mismatched cascaded quadratic optical interactions in nonlinear crystals

    PubMed Central

    Petrov, Georgi I.; Zhi, Miaochan; Yakovlev, Vladislav V.

    2013-01-01

    We experimentally investigated the nonlinear optical interaction between the instantaneous four-wave mixing and the cascaded quadratic frequency conversion in commonly used nonlinear optical KTP and LiNbO3 with the aim of a possible background suppression of the non-resonant background in coherent anti-Stokes Raman scattering. The possibility of background-free heterodyne coherent anti-Stokes Raman scattering microspectroscopy is investigated at the interface formed by a liquid (isopropyl alcohol) and a nonlinear crystal (LiNbO3). PMID:24514791

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Case study: Automated utilities damage assessment (AUDA) system

    SciTech Connect

    Salavani, R.; Laventure, G.C.; Smith, M.D.

    1994-12-31

    A demonstration program of an automated utility damage assessment system (AUDA) at a United States Air Force facility (USAF) is described. The AUDA is designed to assess damage, in an efficient manner, to military equipment or utilities, such as electrical equipment, potable and waste water, HVAC systems, petroleum, oil and lubricants, and natural gas.

  15. 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

  16. Optical Studies of Defects in Aluminum Oxide.

    NASA Astrophysics Data System (ADS)

    James, Floyd Jasper

    Defects in aluminum oxide single crystals were studied using optical absorption, photoluminescence, and thermally stimulated luminescence. The primary defect in Al(,2)O(,3) is the oxygen vacancy. A vacancy trapping 2 electrons, the F center, absorbs at 6.0 eV, and the F('+) center, trapping 1 electron, absorbs at 4.8 eV, 5.4 eV, and possibly 6.1 eV. Neutron bombardment produces F and F('+) centers, while electron bombardment or treatment by growth in a reducing atmosphere makes predominantly F centers. Isochronal and isothermal anneals of neutron-irradiated material show no discrete stages in the annealing of the oxygen vacancy, as monitored by the decrease in optical absorption of the F center, and so no activation energy for the process could be determined. Photoluminescence studies of neutron-irradiated, additively colored, electron irradiated, and growth colored crystals shows the mainly the 6.0 eV - 3.0 eV F center absorption-emission pair, while bombarded samples show reduced F emission, and also F('+) emissions, including the dominant 4.8 - 3.2 eV peak. By using computer controlled excitation and analyzing monochromators, luminescence peak detection was improved, and several new absorption-emission pairs were found. Thermally stimulated luminescence (TSL) was conducted from 77 K to room temperature on growth-colored and non growth-colored samples, using ultraviolet light as the exciting agent. The common 260 K TSL peak is largest at 6.0 eV in exciting wavelength, and shows emission similar to that of the F center. This was not seen in a crystal not containing F centers. Also, a peak at 230 K can be produced in growth-colored crystals by bleaching at about 200 K.

  17. 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.

  18. Three-dimensional display utilizing a diffractive optical element and an active matrix liquid crystal display

    NASA Astrophysics Data System (ADS)

    Nordin, Gregory P.; Jones, Michael W.; Kulick, Jeffrey H.; Lindquist, Robert G.; Kowel, Stephen T.

    1996-12-01

    We describe the design, construction, and performance of the first real-time autostereoscopic 3D display based on the partial pixel 3D display architecture. The primary optical components of the 3D display are an active-matrix liquid crystal display and a diffractive optical element (DOE). The display operates at video frame rates and is driven with a conventional VGA signal. 3D animations with horizontal motion parallax are readily viewable as sets of stereo images. Formation of the virtual viewing slits by diffraction from the partial pixel apertures is experimentally verified. The measured contrast and perceived brightness of the display are excellent, but there are minor flaws in image quality due to secondary images. The source of these images and how they may be eliminated is discussed. The effects of manufacturing-related systematic errors in the DOE are also analyzed.

  19. 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.

  20. 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 have been manufactured with both GaAs and InP, and the improved optical absorption demonstrated. Preferred parameters for various applications are listed and discussed.

  1. 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%.

  2. 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.

  3. 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)

  4. The Utility of Outcome Studies in Plastic Surgery

    PubMed Central

    Sinno, Hani; Dionisopoulos, Tassos; Slavin, Sumner A.; Ibrahim, Ahmed M. S.; Chung, Kevin C.

    2014-01-01

    Summary: Outcome studies help provide the evidence-based science rationalizing treatment end results that factor the experience of patients and the impact on society. They improve the recognition of the shortcoming in clinical practice and provide the foundation for the development of gold standard care. With such evidence, health care practitioners can develop evidence-based justification for treatments and offer patients with superior informed consent for their treatment options. Furthermore, health care and insurance agencies can recognize improved cost-benefit options in the purpose of disease prevention and alleviation of its impact on the patient and society. Health care outcomes are ultimately measured by the treatment of disease, the reduction of symptoms, the normalization of laboratory results and physical measures, saving a life, and patient satisfaction. In this review, we outline the tools available to measure outcomes in plastic surgery and subsequently allow the objective measurements of plastic surgical conditions. Six major outcome categories are discussed: (1) functional measures; (2) preference-based measures and utility outcome scores; (3) patient satisfaction; (4) health outcomes and time; (5) other tools: patient-reported outcome measurement information system, BREAST-Q, and Tracking Operations and Outcomes for Plastic Surgeons; and (6) cost-effectiveness analysis. We use breast hypertrophy requiring breast reduction as an example throughout this review as a representative plastic surgical condition with multiple treatments available. PMID:25426372

  5. 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.

  6. Simplified architecture for photonic analog-to-digital conversion, utilizing an array of optical modulators

    NASA Astrophysics Data System (ADS)

    Gevorgyan, Hayk; Khilo, Anatol

    2016-03-01

    In this work a novel photonic sampled and electronically quantized analog-to-digital converter (ADC) system is introduced. High overall sampling rate and relaxed analog bandwidth requirements for photodetectors and electronic quantizers are attained by multichannel architecture. The proposed scheme, with a dedicated electro-optic modulator for each of the channels, is much simpler and has a perspective to outreach the performance of a similar time- wavelength demultiplexed photonic ADC. Absolute optical power isolation between the channels completely eliminates the issue of channel crosstalk, resulting in increased power efficiency of the system. Owing to small number of wavelength demultiplexers less wavelength alignment is required, which reduces the complexity of both photonic and electronic subsystems. Due to the significance of having compact, on-chip photonic ADCs, the analysis of integration of proposed system on a silicon platform is performed. The availability of high performance devices in various Si platforms, such as low loss Si waveguides, microring resonator filters, modulators, photodetectors, necessary for building the system, proves that the photonic ADC is well suited for integration on a silicon chip. For integrated version of proposed architecture Si microring resonator modulators are suitable. They are compact, and can have shorter total length of diode phase shifters as compared to Mach-Zehnder modulators, used in time-wavelength demultiplexed photonic ADCs. To achieve large modulation depth and lower nonlinear distortions, the choice of optimum optical bandwidth of microring modulator is analyzed. Finally, the nonlinearity analysis of ring modulators is performed and the influence of nonlinearities on the ADC performance is discussed.

  7. Study on optical measurement conditions for noninvasive blood glucose sensing

    NASA Astrophysics Data System (ADS)

    Xu, Kexin; Chen, Wenliang; Jiang, Jingying; Qiu, Qingjun

    2004-05-01

    Utilizing Near-infrared Spectroscopy for non-invasive glucose concentration sensing has been a focusing topic in biomedical optics applications. In this paper study on measuring conditions of spectroscopy on human body is carried out and a series of experiments on glucose concentration sensing are conducted. First, Monte Carlo method is applied to simulate and calculate photons" penetration depth within skin tissues at 1600 nm. The simulation results indicate that applying our designed optical probe, the detected photons can penetrate epidermis of the palm and meet the glucose sensing requirements within the dermis. Second, we analyze the influence of the measured position variations and the contact pressure between the optical fiber probe and the measured position on the measured spectrum during spectroscopic measurement of a human body. And, a measurement conditions reproduction system is introduced to enhance the measurement repeatability. Furthermore, through a series of transmittance experiments on glucose aqueous solutions sensing from simple to complex we found that though some absorption variation information of glucose can be obtained from measurements using NIR spectroscopy, while under the same measuring conditions and with the same modeling method, choices toward measured components reduce when complication degree of components increases, and this causes a decreased prediction accuracy. Finally, OGTT experiments were performed, and a PLS (Partial Least Square) mathematical model for a single experiment was built. We can easily get a prediction expressed as RMSEP (Root Mean Square Error of Prediction) with a value of 0.5-0.8mmol/dl. But the model"s extended application and reliability need more investigation.

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

    NASA Astrophysics Data System (ADS)

    Jung, Yeongri; Guan, Guangying; Wei, Chen-Wei; Reif, Roberto; Gao, Xiaohu; O'Donnell, Matthew; Wang, Ruikang K.

    2012-01-01

    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.

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

    PubMed

    Jung, Yeongri; Guan, Guangying; Wei, Chen-Wei; Reif, Roberto; Gao, Xiaohu; O'Donnell, Matthew; Wang, Ruikang K

    2012-01-01

    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

  10. Utilization of artificial neural networks in the diagnosis of optic nerve diseases.

    PubMed

    Kara, Sadik; Güven, Ayşegül; Oner, Ayşe Oztürk

    2006-04-01

    This research is concentrated on the diagnosis of optic nerve disease through the analysis of pattern electroretinography (PERG) signals with the help of artificial neural network (ANN). Multilayer feed forward ANN trained with a Levenberg Marquart (LM) backpropagation algorithm was implemented. The designed classification structure has about 96.4% sensitivity, 90.4% specifity and positive prediction is calculated to be 94.2%. The end results are classified as healthy and diseased. Testing results were found to be compliant with the expected results that are derived from the physician's direct diagnosis. The end benefit would be to assist the physician to make the final decision without hesitation. PMID:16488775

  11. 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.

  12. Transport and optical studies on individual nanostructures

    NASA Astrophysics Data System (ADS)

    Gu, Qian

    Nanotechnology is considered a very important scientific discipline. It probably will offer tremendous growth opportunities to many industries. Numerous nanostructures showing interesting and practical properties have been synthesized. In order to fully understand and assemble these nanostructures into useful "nano-machines", investigations on individual nanostructures are needed. This thesis will present electron transport studies on individual organic molecules, a new method of fabricating asymmetric junctions to contact individual nanostructures, and synthesis, electrical and optical characterizations on single vanadium dioxide nanobeams. Chapter 1 serves as a brief introduction to the progress and challenges in nanotechnology. Chapter 2 first introduces single charge tunneling theory, and then discusses in detail the fabrication of single molecule transistors. Finally, this chapter presents a novel electrodeposition-based method to fabricate electrode pairs of dissimilar metals with a nanometer-sized gap between them. This electrodeposition-based method prevents cross-contamination of the different metals and enables simultaneous fabrication of multiple electrode pairs in a self-limiting manner. Chapter 3 presents electron transport studies on single molecule transistors based on individual ferrocene and nickelocene molecules. These devices show clean Coulomb blockade and energy quantization at liquid helium temperature. Low energy excited states are attributed to ring-torsion and center-of-mass vibrational modes of these molecules. Chapter 4 discusses electron transport properties of single molecule transistors based on individual [W6CCl18]n- molecules. Besides Coulomb blockade and energy quantization, these transistors demonstrate that tunneling electrons change the vibrational spectrum of [W 6CCl18]n- molecules and the vibrational modes in turn affect electron tunneling. Chapter 5 presents a vapor transport synthetic method of single crystalline vanadium

  13. 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

  14. 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

  15. 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…

  16. 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.

  17. Utilization of photoreversible optical nonlinearities in trans-cis photochromic molecules for spatial light modulation

    NASA Astrophysics Data System (ADS)

    Dantsker, D.; Speiser, S.

    1994-02-01

    In this paper we examine the nonlinear optical properties of molecular systems undergoing a cis-trans photoisomerization process. Such a process gives rise to dynamic photochromism on a picosecond time scale significant for designing a molecular Spatial Light Modulator (SLM). A kinetic analysis of a general cis-trans nonlinear organic absorber is performed. The analysis is used to derive an expression for the imaginary part of the complex nonlinear molecular index of refraction. The properties of a molecular SLM based on such an absorber are discussed by examining the azo-type molecular system. These calculation predict an optimum contrast ratio and fast on-off switching for the SLM performance, achieved at low read-write laser intensities.

  18. 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.

  19. 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.

  20. 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.

  1. Multichannel optical correlator/convolver utilizing the magnetooptic spatial light modulator

    NASA Technical Reports Server (NTRS)

    Davis, Jeffrey A.; Day, Timothy; Lilly, Roger A.; Liu, Hua-Kuang

    1987-01-01

    The paper describes a multichannel correlator/convolver architecture utilizing an acoustooptic light modulator for the one dimensional channel and a magnetooptic spatial light modulator (MOSLM) for the second two-dimensional parallel channel. The MOSLM allows greater parallelism to be implemented in this correlator/convolver design than was previously reported. The implementation of 24 parallel channels with a 48 x 48 device is demonstrated. Experimental data are presented and the ways of increasing the number of parallel channels using commercially available MOSLMs and other previously discussed techniques, such as frequency multiplexing, are discussed. It is shown that over 2000 parallel channels are possible at 32-bit accuracy. A technique for obtaining a limited gray scale is also discussed.

  2. 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.

  3. 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.

  4. 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.

  5. BOILER SIMULATOR STUDIES ON SORBENT UTILIZATION FOR SO2 CONTROL

    EPA Science Inventory

    The report gives results of a program to provide process design information for sorbent utilization as applied to EPA's LIMB process. Specifically, the program was designed to investigate the role of boiler thermal history, sorbent injection location, Ca/S molar ratio, and SO2 pa...

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

    PubMed

    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

  7. 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

  8. 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. PMID:25321766

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. Multimode optical fiber study for a new radiation dosimeter development

    NASA Astrophysics Data System (ADS)

    Badita, Eugenia; Stancu, Elena; Scarlat, Florea; Vancea, Catalin; Dumitrascu, Maria; Scarisoreanu, Anca

    2013-06-01

    This paper presents the experimental results on preliminary study of the physical proprieties of the multimode optical fiber in radiation field delivered by electron linear accelerator of the National Research and Development Institute for Laser, Plasma and Radiation Physics (INFLPR). This study is based on the physical degradation effect of the optical fiber due to electron beam exposure measured through dependence of the exposure dose in electron beam and radiation induced attenuation. Optical fiber attenuations were measured before, during and after electron beam exposure. Results show a greater attenuation for multimode optical fiber of lower wavelength.

  14. 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

  15. 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.

  16. 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)

  17. 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.

  18. 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.

  19. Propeller aircraft interior noise model utilization study and validation

    NASA Astrophysics Data System (ADS)

    Pope, L. D.

    1984-09-01

    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.

  20. Optical studies of meteors at Mount Hopkins Observatory

    NASA Technical Reports Server (NTRS)

    Weekes, T. C.; Williams, J. T.

    1974-01-01

    The 10-m optical reflector and an array of phototubes are used to extend the optical measurements beyond the present limit achieved by the Vidicon system. The first detection of optical meteors with M sub v = + 12 is reported. It is hoped that this system can be used to determine intermediate points in the meteor frequency mass curve for sporadic meteors and to study in detail the faint components of meteor showers. Preliminary observations made on three nights in September 1974 are presented.

  1. Utilization of optical tracking to assess efficacy of intracranial immobilization techniques in proton therapy.

    PubMed

    Hsi, Wen C; Schreuder, Andries N; Zeidan, Omar

    2015-01-01

    We present a quantitative methodology to measure head interfraction movements within intracranial masks of commercial immobilization devices used for proton radiotherapy. A three-points tracking (3PtTrack) method was developed to measure the mask location for each treatment field over an average of 10 fractions for seven patients. Five patients were treated in supine with the Qfix Base-of-Skull (BoS) headframe, and two patients were treated in prone with the CIVCO Uni-frame baseplate. Patients were first localized by an in-room, image-guidance (IG) system, and then the mask location was measured using the 3PtTrack method. Measured mask displacements from initial location at the first fraction are considered equivalent to the head interfraction movement within the mask. The trends of head movements and couch displacements and rotation were analyzed in three major directions. The accuracy of 3PtTrack method was shown to be within 1.0mm based on daily measurements of a QA device after localization by the IG system for a period of three months. For seven patients, mean values of standard deviation (SD) in anterior-posterior, lateral, and superior-inferior directions were 1.1mm, 1.4 mm, and 1.6 mm for head movements, and were 1.4 mm, 1.8 mm, and 3.4mm for couch displacements. The mean SD values of couch rotations were 1.1°, 0.9°, and 1.1° for yaw, pitch, and roll, respectively. The overall patterns of head movements and couch displacements were similar for patients treated in either supine or prone, with larger deviations in the superior-inferior (SI) direction. A suboptimal mask fixation to the frame of the mask to the H&N frame is likely the cause for the observed larger head movements and couch displacements in the SI direction compared to other directions. The optical-tracking methodology provided a quantitative assessment of the magnitude of head motion. PMID:26699301

  2. Optical tweezers study life under tension

    NASA Astrophysics Data System (ADS)

    Fazal, Furqan M.; Block, Steven M.

    2011-06-01

    Optical tweezers have become one of the primary weapons in the arsenal of biophysicists, and have revolutionized the new field of single-molecule biophysics. Today's techniques allow high-resolution experiments on biological macromolecules that were mere pipe dreams only a decade ago.

  3. Windows software for enhanced studying and testing knowledge in optics

    NASA Astrophysics Data System (ADS)

    Stafeev, Sergey C.; Michnovetz, Vladimir J.; Khmaladze, Alexander T.; Zinchik, Alexander A.

    1995-10-01

    We describe recent advances in the development of the original software for studying optics on the General Physics level. Two types of Windows software are reported: the guide-programs for simulation the basic optical experiments and the multichoice test-programs for teachers (to create tests) and for students (to check their knowledge). Application of guide-programs combined with image-files from CCD-camera is presented in two modes; with real equipment and simulation with empirical data- files. The testing system uses GRE approach and accompanied a lot of pictures with main optical circuits or charts. Some illustrations with real screen views for basic optical phenomena are presented.

  4. 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.

  5. Theoretical study of Fourier-transform acousto-optic imaging.

    PubMed

    Barjean, Kinia; Ramaz, François; Tualle, Jean-Michel

    2016-05-01

    We propose a full theoretical study of Fourier-transform acousto-optic imaging, which we recently introduced and experimentally assessed in [Opt. Lett.40, 705-708 (2015)OPLEDP0146-959210.1364/OL.40.000705] as an alternative to achieve axial resolution in acousto-optic imaging with a higher signal-to-noise ratio. PMID:27140883

  6. Laser tomography adaptive optics: a performance study.

    PubMed

    Tatulli, Eric; Ramaprakash, A N

    2013-12-01

    We present an analytical derivation of the on-axis performance of adaptive optics systems using a given number of guide stars of arbitrary altitude, distributed at arbitrary angular positions in the sky. The expressions of the residual error are given for cases of both continuous and discrete turbulent atmospheric profiles. Assuming Shack-Hartmann wavefront sensing with circular apertures, we demonstrate that the error is formally described by integrals of products of three Bessel functions. We compare the performance of adaptive optics correction when using natural, sodium, or Rayleigh laser guide stars. For small diameter class telescopes (≲5 m), we show that a small number of Rayleigh beacons can provide similar performance to that of a single sodium laser, for a lower overall cost of the instrument. For bigger apertures, using Rayleigh stars may not be such a suitable alternative because of the too severe cone effect that drastically degrades the quality of the correction. PMID:24323009

  7. Machine optics studies for the LHC measurements

    NASA Astrophysics Data System (ADS)

    Trzebiński, Maciej

    2014-11-01

    In this work the properties of scattered protons in the vicinity of the ATLAS Interaction Point (IP1) for various LHC optics settings are discussed. Firstly, the beam elements installed around IP1 are presented. Then the ATLAS forward detector systems: Absolute Luminosity For ATLAS (ALFA) and ATLAS Forward Protons (AFP) are described and their similarities and differences are discussed. Next, the various optics used at Large Hadron Collider (LHC) are described and the beam divergence and width at the Interaction Point as well as at the ATLAS forward detectors locations are calculated. Finally, the geometric acceptance of the ATLAS forward detectors is shown and the impact of the LHC collimators on it is discussed.

  8. 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.

  9. 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.

  10. 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.

  11. Spectromicroscopy Study of the Organic Molecules Utilizing Polarized Radiation

    SciTech Connect

    Hsu, Y.J.; Wei, D.H.; Yin, G.C.; Chung, S.C.; Hu, W.S.; Tao, Y.T.

    2004-05-12

    Spectromicroscopy combined with polarized synchrotron radiation is a powerful tool for imaging and characterizing the molecular properties on surface. In this work we utilized the photoemission electron microscopy (PEEM) with linear polarized radiation provided by an elliptically polarized undulator to investigate the molecular orientations of pentacene on self-assembled monolayer (SAMs) modified gold surface and to observe the cluster domain of mixed monolayers after reorganization on silver. Varying the electric vector parallel or perpendicular to the surface, the relative intensity of {pi}* and {sigma}* transition in carbon K-edge can be used to determine the orientation of the planar-shaped pentacene molecule or long carbon chain of carboxylic acids which are important for organic semiconductor.

  12. A study on the Jordanian oil shale resources and utilization

    NASA Astrophysics Data System (ADS)

    Sakhrieh, Ahmad; Hamdan, Mohammed

    2012-11-01

    Jordan has significant oil shale deposits occurring in 26 known localities. Geological surveys indicate that the existing deposits underlie more than 60% of Jordan's territory. The resource consists of 40 to 70 billion tones of oil shale, which may be equivalent to more than 5 million tones of shale oil. Since the 1960s, Jordan has been investigating economical and environmental methods for utilizing oil shale. Due to its high organic content, is considered a suitable source of energy. This paper introduces a circulating fluidized bed combustor that simulates the behavior of full scale municipal oil shale combustors. The inside diameter of the combustor is 500 mm, the height is 3000 mm. The design of the CFB is presented. The main parameters which affect the combustion process are elucidated in the paper. The size of the laboratory scale fluidized bed reactor is 3 kW, which corresponds to a fuel-feeding rate of approximately 1.5 kg/h.

  13. 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.

  14. Comprehensive optical study of the dragonfly Aeshna cyanea transparent wing

    NASA Astrophysics Data System (ADS)

    Dompreh, K. A.; Eghan, M. J.; Kotsedi, L.; Maaza, M.

    2013-06-01

    The optical properties of the transparent wings of the Dragonfly Aeshna cyanea were studied using a comprehensive set of optical measurements, experimental analysis and theoretical modeling which involves the use of a high level programming language to simulate the optical effects seen. With these, the relative refractive index of the Odonatan wing, the pruinosity associated with the microstructure and the chemical composition of the wings were studied. The Nystrom matrix techniques were applied to solve the surface currents JZ and HZ of the scattered fields for different incident angles from grazing and used to explain the pruinosity associated with the wings microstructure. The wing was found to be an Electro-Optic Material (EOM) associated with a number of Nonlinear Optical (NLO) responses having high frequency absorption for extreme UV and also, leaky multi-channeling wave guide.

  15. 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.

  16. 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.

  17. 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.

  18. Isotopomer Spectral Analysis: Utilizing Nonlinear Models in Isotopic Flux Studies.

    PubMed

    Kelleher, Joanne K; Nickol, Gary B

    2015-01-01

    We present the principles underlying the isotopomer spectral analysis (ISA) method for evaluating biosynthesis using stable isotopes. ISA addresses a classic conundrum encountered in the use of radioisotopes to estimate biosynthesis rates whereby the information available is insufficient to estimate biosynthesis. ISA overcomes this difficulty capitalizing on the additional information available from the mass isotopomer labeling profile of a polymer. ISA utilizes nonlinear regression to estimate the two unknown parameters of the model. A key parameter estimated by ISA represents the fractional contribution of the tracer to the precursor pool for the biosynthesis, D. By estimating D in cells synthesizing lipids, ISA quantifies the relative importance of two distinct pathways for flux of glutamine to lipid, reductive carboxylation, and glutaminolysis. ISA can also evaluate the competition between different metabolites, such as glucose and acetoacetate, as precursors for lipogenesis and thereby reveal regulatory properties of the biosynthesis pathway. The model is flexible and may be expanded to quantify sterol biosynthesis allowing tracer to enter the pathway at three different positions, acetyl CoA, acetoacetyl CoA, and mevalonate. The nonlinear properties of ISA provide a method of testing for the presence of gradients of precursor enrichment illustrated by in vivo sterol synthesis. A second ISA parameter provides the fraction of the polymer that is newly synthesized over the time course of the experiment. In summary, ISA is a flexible framework for developing models of polymerization biosynthesis providing insight into pools and pathway that are not easily quantified by other techniques. PMID:26358909

  19. 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

    2015-01-01

    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). PMID:26198220

  20. Study on application of optical clearing technique in skin diseases

    NASA Astrophysics Data System (ADS)

    Shan, Hao; Liang, Yanmei; Wang, Jingyi; Li, Yan

    2012-11-01

    So far, the study of the optical clearing is almost always about healthy tissue. However, the ultimate goal is to detect diseases for clinical application. Optical clearing on diseased skins is explored. The effect is evaluated by applying a combined liquid paraffin and glycerol mixed solution on several kinds of diseased skins in vitro. Scanning experiments from optical coherence tomography show that it has different effects among fibroma, pigmented nevus, and seborrheic keratosis. Based on the results, we conclude that different skin diseases have different compositions and structures, and their optical parameters and biological characteristics should be different, which implies that the optical clearing technique may have selectivity and may not be suitable for all kinds of skin diseases.

  1. Experimental studies of electro-optic polymer modulators and waveguides

    NASA Astrophysics Data System (ADS)

    Hedin, Eric R.; Goetz, Frederick J.

    1995-03-01

    The results of an experimental study of electro-optic modulators and waveguides based on polymeric materials are presented. Included are the design, fabrication, and testing of integrated Mach-Zehnder modulators, which are based on polymer films that contain a novel, nonlinear electro-optic chromophore. Studies also show the efficacy of photolithography or photobleaching by the use of this chromophore to form passive, branching waveguides, which are operated at the 1300-nm wavelength.

  2. 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. PMID:22070992

  3. 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. PMID:22418506

  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. 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.

  6. 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.

  7. 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

  8. A Study of Educational Knowledge Diffusion and Utilization.

    ERIC Educational Resources Information Center

    Wolf, W. C., Jr.; Fiorino, A. John

    Some six hundred educators were studied in depth to determine their experiences with innovation, the influences of recognized diffusion agents upon their adoption of innovations, the characteristics of selected target audiences in relation to the adoption of innovations to personal practice, and relationships between five distinguishable stages of…

  9. LANDFILL GAS ENERGY UTILIZATION: TECHNOLOGY OPTIONS AND CASE STUDIES

    EPA Science Inventory

    The report discusses technical, environmental, and other issues associated with using landfill gas as fuel, and presents case studies of projects in the U.S. illustrating some common energy uses. he full report begins by covering basic issues such as gas origin, composition, and ...

  10. Conceptualization and Utility of University Mattering: A Construct Validity Study

    ERIC Educational Resources Information Center

    France, Megan K.; Finney, Sara J.

    2010-01-01

    The purpose of this study was to gather validity evidence for the University Mattering Scale. Theoretically based factor structures were tested, resulting in the four-factor conceptualization of mattering being championed. As predicted, university mattering related positively to academic motivational and relatedness constructs and negatively to…

  11. A Study of Counselors and Their Utilization of Counseling Skills.

    ERIC Educational Resources Information Center

    Tatar, Marina; Tracer, Edith

    In October of 1974 a follow-up study was conducted using a sample of 50 Master's level graduates in guidance and counseling from Northeastern Illinois University. Questionnaires were mailed to derive information relative to (1) professional employment, current and preferred, (2) professional skills most frequently used and (3) graduate courses…

  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. 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

  14. Airborne optical tracking control system design study

    NASA Astrophysics Data System (ADS)

    1992-09-01

    The Kestrel LOS Tracking Program involves the development of a computer and algorithms for use in passive tracking of airborne targets from a high altitude balloon platform. The computer receivers track error signals from a video tracker connected to one of the imaging sensors. In addition, an on-board IRU (gyro), accelerometers, a magnetometer, and a two-axis inclinometer provide inputs which are used for initial acquisitions and course and fine tracking. Signals received by the control processor from the video tracker, IRU, accelerometers, magnetometer, and inclinometer are utilized by the control processor to generate drive signals for the payload azimuth drive, the Gimballed Mirror System (GMS), and the Fast Steering Mirror (FSM). The hardware which will be procured under the LOS tracking activity is the Controls Processor (CP), the IRU, and the FSM. The performance specifications for the GMS and the payload canister azimuth driver are established by the LOS tracking design team in an effort to achieve a tracking jitter of less than 3 micro-rad, 1 sigma for one axis.

  15. 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.

  16. 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.

  17. Utilizing Cloud Computing to Improve Climate Modeling and Studies

    NASA Astrophysics Data System (ADS)

    Li, Z.; Yang, C.; Liu, K.; Sun, M.; XIA, J.; Huang, Q.

    2013-12-01

    Climate studies have become increasingly important due to the global climate change, one of the biggest challenges for the human in the 21st century. Climate data, not only observations data collected from various sensors but also simulated data generated from diverse climate models, are essential for scientists to explore the potential climate change patterns and analyze the complex climate dynamics. Climate modeling and simulation, a critical methodology for simulating the past and predicting the future climate conditions, can produce huge amount of data that contains potentially valuable information for climate studies. However, using modeling method in climate studies poses at least two challenges for scientists. First, running climate models is a computing intensive process, which requires large amounts of computation resources. Second, running climate models is also a data intensive process generating Big geospatial Data (model output), which demands large storage for managing the data and large computing power to process and analyze these data. This presentation introduces a novel framework to tackle the two challenges by 1) running climate models in a cloud environment in an automated fashion, and 2) managing and parallel processing Big model output Data by leveraging cloud computing technologies. A prototype system is developed based on the framework using ModelE as the climate model. Experiment results show that this framework can improve climate modeling in the research cycle by accelerating big data generation (model simulation), big data management (storage and processing) and on demand big data analytics.

  18. 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

  19. 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

  20. Comparing Utility Scores in Common Spinal Radiculopathies: Results of a Prospective Valuation Study.

    PubMed

    Nayak, Nikhil R; Stephen, James H; Abdullah, Kalil G; Stein, Sherman C; Malhotra, Neil R

    2016-05-01

    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

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

    PubMed

    Mishra, Satyendra K; Gupta, Banshi D

    2013-05-01

    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. PMID:23486702

  2. 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

  3. 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

  4. Electric utility system planning studies for OTEC power integration

    NASA Astrophysics Data System (ADS)

    1980-11-01

    The integration of OTEC into the Florida Power Corporation (FTC) system was evaluated. Existing system planning procedures, assumptions, and corporate financial criteria for planning generating capacity were used without modification. A baseline configuration for an OTEC plant was developed for review with standard planning procedures. The OTEC plant characteristics and costs were incorporated in considerable detail. It was found that with the initial set of conditions, OTEC would not be economically viable. Using the same system planning procedures, a number of adjustments were made to the key study assumptions. It was found that two considerations dominate the analysis: the assumed rate of fuel cost escalation, and the projected capital cost of the OTEC plant. After corporate financial analysis, it was found that even if the cost competitive criterion were to be reached, the plan including OTEC could not be financed by FPC.

  5. Task 3 -- Bench-scale char upgrading and utilization study

    SciTech Connect

    Jha, M.C.; McCormick, R.L.

    1989-08-02

    This report describes the results of the bench-scale char upgrading study conducted as Task 3 of Development of an Advanced, Continuous Mild Gasification Process for the Production of Coproducts. A process where the char is gasified to produce methane in a first stage reactor was investigated. This methane is then decomposed to produce carbon and hydrogen for recycle in a second stage. The results indicate that both reaction steps are feasible using mild gasification char as the starting feedstock. Conditions for methanation are 700 to 800 C and 200 to 400 psig. Carbon formation conditions are 1,200 to 1,400 C at atmospheric pressure. The carbon produced has properties similar to those of carbons which are commercially marketed as carbon black.

  6. Might Hallucinations Have Social Utility?: A Proposal for Scientific Study.

    PubMed

    Kauffman, Paul Richard

    2016-09-01

    There are many historical examples of people who heard voices or saw visions but were not classified as having a mental illness and who were supported by a religious community. The article offers a perspective for effective psychosocial supports for schizophrenia. The author analyzes data on 95 people who experienced verifiable persistent non-drug-assisted hallucinations in Europe, North America, and Australasia and discusses the life outcomes of 39 subjects. They include founders of religions, dysfunctional monarchs, persons with cosmological beliefs, and mental health workers. Their psychoses were intrinsic to their personalities and contributions. Hallucinations generated by psychosis were useful for cultural innovation, particularly in religion as many hallucinators were integrated into church history. Community, work, friendship, and supportive practices are discussed. A scientific study of effective psychosocial support to supplement medication for schizophrenia is outlined. PMID:27570899

  7. (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.

  8. Energy related studies utilizing K-feldspar thermochronology

    NASA Astrophysics Data System (ADS)

    In our second year of funding, we 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 C. The effect that is observed involves a correlation between the homogenization of cryptoperthite lamelle and the apparent increase in retentivity of about 5 percent 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 appear to 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 Ar-40/Ar-39 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.

  9. 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.

  10. Utilization of novel atom sources in studies of semiconductor surfaces

    NASA Astrophysics Data System (ADS)

    Wolan, John Thaddeus

    Nanometer-scale characterization of semiconductor surfaces is very important for precise control of the ultrafine structures necessary for the realization of devices using quantum confinement. The performance of these heterojunction devices is strongly dependent on interface quality. In the case of III-V semiconductors, the major problem is the presence of the native oxide layer and surface carbon contamination. This carbon is strongly bonded to the III-V surface even after ion-etching and high temperature annealing and induces a free-carrier depletion region at the substrate-epilayer interface. Furthermore, native oxides on GaAs and InP surfaces are detrimental to the formation of stable interfaces and can result in defective epitaxial growth, inducing undesirable electrical characteristics to the device so they must be removed without damaging the near-surface region. A surface characterization study using ion scattering spectroscopy (ISS) and X-ray photoelectron spectroscopy (XPS) has been performed on GaAs(001) and InP(111) substrates before and after cleaning by ion sputtering/annealing cycles and room temperature exposure to the flux produced by a novel atomic hydrogen source based on electron-stimulated desorption (ESD) to determine any treatment-induced alterations. In order to realize high performance III-V circuits, the preparation of a good quality passivating oxide interface is necessary. Device quality oxide-(III-V) interface fabrication will certainly depend on the composition of the oxide interface and any possible damage induced by the oxidation process. In the case of GaAs, thermal oxides and formation of thick oxides (which actually is diffusion-controlled and possibly close to thermal equilibrium) usually results in non-stoichiometric films of Gasb2Osb3 and Assb2Osb3 as well as a pile-up of elemental As at the GaAs-oxide interface. This structure is predicted by the Ga-O-As phase diagram, but it provides poor electrical isolation and surface

  11. Coleman Highlands subsurface air utilization study. Final report

    SciTech Connect

    Shapiro, M.D.

    1982-11-15

    An investigation was conducted into the feasibility of using a 1 million square foot developed cave within the Downtown Industrial Park as a heating and cooling source for a proposed residential subdivision on an adjacent vacant tract of land. Both sites are located near the Coleman Highlands neighborhood in the Westport Community of Kansas City, Missouri. Characteristics of the cave and surface sites were studied, as well as potential heating and cooling sources and transfer media. BTU capacity of the cave and demand for the prototype houses was calculated. The preferred system included a water source in the cave, water transfer medium, and water-to-air heat pumps in the individual homes. Analysis of that system showed it would be marginally effective due to the limited heat valve available in the cave and substantial shortfalls of cooling capacity for summertime operation. Estimated system costs appeared to be in an affordable range, but it was felt that those capital costs could be better applied to other energy-conserving measures.

  12. Treatment Utility of Postpartum Antibiotics in Chorioamnionitis Study.

    PubMed

    Shanks, Anthony L; Mehra, Suwan; Gross, Gil; Colvin, Ryan; Harper, Lorie M; Tuuli, Methodius G

    2016-07-01

    Objective To determine if postpartum antibiotics are necessary for patients with chorioamnionitis after a cesarean delivery (CD). Study Design Multicenter randomized controlled trial. Laboring patients with singleton gestations and chorioamnionitis who underwent CD were eligible. Patients were treated with ampicillin and gentamicin per standard protocol, then given clindamycin prior to skin incision. Patients were randomized to either postpartum antibiotic prophylaxis or no treatment following delivery. The primary outcome was the rate of endometritis. Assuming a 30% risk of endometritis in patients with chorioamnionitis who undergo CD, 119 patients per arm would be required to detect a 50% decrease in endometritis. Results The trial was stopped for futility following a planned interim analysis after 80 patients were randomized. There was no difference in the rate of the primary outcome between the two groups (9.8 vs. 7.7%, relative risk [RR]: 1.27; 95% confidence interval [CI]: 0.30, 5.31). A meta-analysis comparing post-CD antibiotics versus no treatment did not find a statistically significant difference between the groups (16.7 vs. 12.0%, pooled RR: 1.43; 95% CI: 0.72, 2.84). Conclusion Additional postpartum antibiotics do not decrease the rate of endometritis in patients with chorioamnionitis who undergo CD. The current preoperative antibiotic regimen including clindamycin should remain the standard of care in these patients. PMID:26890440

  13. Turndown studies for utility fluidized-bed boilers. Final report

    SciTech Connect

    Divilio, R.J.; Reed, R.R.

    1984-01-01

    This report contains a series of analyses that evaluate the turndown potential of the EPRI 6 x 6 test facility and the TVA 20 MW FBC pilot plant by variation of the fluidization velocity. The basis of the analyses is a heat balance program that incorporates basic principles of thermodynamics and fluidization. The heat balance program is used to explain the interrelationship of operating variables of a fluidized-bed boiler and to predict the steady state operating conditions of the boilers over a range of loads. Turndown analyses were performed on two tube bundle designs for the EPRI 6 x 6 test unit including a nine drawer tube bundle designed for 8 ft/sec operation and a twelve drawer bundle for operation up to 12 ft/sec. This twelve drawer bundle was found to have reasonable turndown characteristics between 4 and 12 ft/sec. At a 20 inch static bed depth, for example, this bundle should operate between 1545 and 1620/sup 0/F at 3.2% O/sub 2/ for loads from 4 to 12 ft/sec. In addition to the two bundles studies, a tube bundle capable of a 3:1 turndown range with a minimum temperature variation was designed for the 6 x 6 test facility. The tube bundle for the TVA 20 MW pilot plant was found to have excellent turndown characteristics between 4 and 8 ft/sec. For example, a 21 inch static bed should allow operation between 1541 and 1575/sup 0/F bed temperature at 3% O/sub 2/.

  14. 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.

  15. Thermal stress studies using optical holographic interferometry

    NASA Technical Reports Server (NTRS)

    Harris, W. J.; Woods, D. C.

    1974-01-01

    The application of holography to thermal stress studies is discussed. Interference fringes as produced by holograms and their interpretation are reviewed in relation to workpiece displacement. Three potential mechanisms are given to explain thermal displacement as detected by holographic methods. Results of some thermal stressing studies are reported, including tests on a live rocket motor.

  16. A Study of Global Cirrus Optical and Microphysical Properties Based on an Efficient Infrared Retrieval Method

    NASA Astrophysics Data System (ADS)

    Li, Y.; Heidinger, A. K.

    2015-12-01

    Current studies of global upper tropospheric cirrus clouds from satellite observations are focused on daytime, primarily due to dependence on solar reflectance in the retrieval technique. Here, utilizing an accurate and efficient infrared based retrieval technique, cirrus cloud optical properties, including cloud optical thickness and effective particle size, are investigated using Aqua MODIS data during both day and night conditions. It is revealed that contrast of averaged day and night properties is small, despite of an apparent distinction in occurrence frequencies. The geographical differences are more pronounced. Seasonal variations, vertical distributions, as well as interrelations with other macrophysical and microphysical properties are also studied. The findings of this study will be useful for developing future cirrus cloud parameterization schemes in climate models.

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. Fiber-tile optical studies at Argonne

    SciTech Connect

    Underwood, D.G.; Morgan, D.J.; Proudfoot, J.

    1991-07-23

    In support of a fiber-tile calorimeter for SDC, we have done studies on a number of topics. The most basic problems were light output and uniformity of response. Using a small electron beam, we have studied fiber placement, tile preparation, wrapping and masking, fiber splicing, fiber routing, phototube response, and some degradation factors. We found two configurations which produced more light output than the others and reasonably uniform response. We have chosen one of these to go into production for the EM test module on the basis of fiber routing for ease of assembly of the calorimeter. We have also applied some of the tools we developed to CDF end plug tile uniformity, shower max testing and development for a couple of detectors, and development of better techniques for radiation damage studies. 18 figs.

  3. Barriers to healthcare utilization in fatiguing illness: a population-based study in Georgia

    PubMed Central

    Lin, Jin-Mann S; Brimmer, Dana J; Boneva, Roumiana S; Jones, James F; Reeves, William C

    2009-01-01

    Background The purpose of this study was to determine the prevalence of barriers to healthcare utilization in persons with fatiguing illness and describe its association with socio-demographics, the number of health conditions, and frequency of healthcare utilization. Furthermore, we sought to identify what types of barriers interfered with healthcare utilization and why they occurred. Methods In a cross-sectional population-based survey, 780 subjects, 112 of them with chronic fatigue syndrome (CFS), completed a healthcare utilization questionnaire. Text analysis was used to create the emerging themes from verbatim responses regarding barriers to healthcare utilization. Multiple logistic regression was performed to examine the association between barriers to healthcare utilization and other factors. Results Forty percent of subjects reported at least one barrier to healthcare utilization. Of 112 subjects with CFS, 55% reported at least one barrier to healthcare utilization. Fatiguing status, reported duration of fatigue, insurance, and BMI were significant risk factors for barriers to healthcare utilization. After adjusting for socio-demographics, medication use, the number of health problems, and frequency of healthcare utilization, fatiguing status remained significantly associated with barriers to healthcare utilization. Subjects with CFS were nearly 4 times more likely to forego needed healthcare during the preceding year than non-fatigued subjects while those with insufficient fatigue (ISF) were nearly 3 times more likely. Three domains emerged from text analysis on barriers to healthcare utilization: 1) accessibility; 2) knowledge-attitudes-beliefs (KABs); and, 3) healthcare system. CFS and reported duration of fatigue were significantly associated with each of these domains. Persons with CFS reported high levels of healthcare utilization barriers for each domain: accessibility (34%), healthcare system (25%), and KABs (19%). In further examination of barrier

  4. Optical and photoelectrochemical study of WTe2 single crystals

    NASA Astrophysics Data System (ADS)

    Desai, P. F.; Patel, D. D.; Bhavsar, D. N.; Jani, A. R.

    2013-06-01

    Single crystals of Tungsten Ditelluride (WTe2) having a layered structure grown by chemical vapor transport method using iodine as the transporting agent are studied here. The optical response of these crystals has been obtained by UV-Vis-NIR spectroscopy at room temperature. Results of optical spectra have been analyzed on the basis of three dimensional models. Photoelectrochemical (PEC) characterization of WTe 2 single crystals have been carried out. Photo response measurements were obtained at different intensities of light source to illuminate the photoanode. The effect of intensity in the efficiency of PEC solar cell has been studied. The implications of the results have been discussed.

  5. Study of technical and economic feasibility of fuel cell cogeneration applications by electric utilities

    NASA Astrophysics Data System (ADS)

    Ku, W. S.; Wakefield, R. A.

    1981-10-01

    A previous EPRI study showed significant potential penetrations of fuel cells into the future generation mixes of U.S. electric utilities. A new EPRI-sponsored study was conducted to investigate the possible additional benefits of operating these utility-owned fuel cells as cogeneration facilities. Three classes of applications were evaluated: residential and commercial buildings, industrial processes and utility power plants. Incremental breakeven capital costs between cogenerating and electric-only fuel cells were determined with respect to conventional thermal energy supply alternatives. The results showed that there are sufficient economic incentives for fuel cell cogeneration in all three classes of applications.

  6. 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...

  7. Nonlinear optical studies on cuprous oxide using two-photon excitation

    NASA Astrophysics Data System (ADS)

    Mani, Shahin Engakkattil

    The ongoing miniaturization of conventional electron-based circuits calls for developments that integrate optics and electronics. Although optical computation is a futuristic proposition, devices utilizing coherent and coupled states of photons and elementary excitations in semiconductors have the potential to emerge as the building blocks of future quantum information processing systems.[1, 2] Our study here aims at gaining an understanding of the fundamental aspects that can serve as a small step on the way to future applications. Excitons and exciton-polaritons are elementary excitations of a semiconductor that are created by optical excitation. An exciton is a bound state of an electron and a hole, while an exciton-polariton is a coherent superposition of an exciton and a photon. These quasi-particles exhibit quantum-mechanical properties that can be exploited to create an exotic state of matter, a phase-transition in which a macroscopic number of particles enter the same quantum state, called a Bose-Einstein Condensate (BEC). In the quest to realize BEC of excitons in solid-state systems, cuprous oxide (Cu2O) is believed to be an excellent candidate and has a rich history as a prototype material for studying high-density exciton physics.[3, 4, 5] It is for this reason that inspite of the rigorous research for over three decades, we still continue to address the challenges associated with excitonic BEC in Cu2O. Optical experiments in Cu2O are mainly conducted on natural geological crystals which are limited in supply. One of the major impediments to researchers studying this material is the difficulty in fabricating good quality crystals having long exciton lifetimes. With our optimized thermal oxidation technique, high-quality synthetic Cu2O single-crystals can be readily prepared in various morphologies, thereby opening avenues for a wide range of experiments. Despite the extensive optical studies of excitons and polaritons in Cu2O, little is known about the

  8. 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.

  9. Theoretical studies for novel non-linear optical crystals

    NASA Astrophysics Data System (ADS)

    Wu, Kechen; Chen, Chuangtian

    1996-09-01

    To fulfil the "molecular engineering" of non-linear optical crystals, two theoretical models suitable respectively for the studies of the absorption edge and birefringence of a non-linear optical crystal have been set up. Molecular quantum chemical methods have been adopted in the systematic calculations of some typical crystals. DV-SCM-X α methods have been used to calculate the absorption edge on the UV side of BBO, LBO, KB5, KDP, Na 2SbF 5, Ba 2TiSi 2O 8, iodate and NaNO 2 crystals. Ab initio methods have been adopted to study the birefringence of NaNO 2, BBO, LiIO 3 and urea crystals. All the theoretical results agreed well with the experimental values. The relationship between structure and properties has been discussed. The results will be helpful to the search for novel non-linear optical crystals.

  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. 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.

  12. Third order optical nonlinearity and optical limiting studies of propane hydrazides

    NASA Astrophysics Data System (ADS)

    Naseema, K.; Manjunatha, K. B.; Sujith, K. V.; Umesh, G.; Kalluraya, Balakrishna; Rao, Vijayalakshmi

    2012-09-01

    Four hydrazones, 2-(4-isobutylphenyl)-N'-[phenylmethylene] propanehydrazide (P1), 2-(4-isobutylphenyl)-N'-[(4- tolyl)methylene] propane hydrazide (P2), 2-(4-isobutylphenyl)-N'-[1-(4- chlorophenyl)ethylidene] propanehydrazide (P3) and 2-(4-isobutylphenyl)-N'-[1-(4-Nitrrophenyl)ethylidene] propane hydrazide (P4) were synthesized and their third order nonlinear optical properties have been investigated using a single beam Z-scan technique with nanosecond laser pulses at 532 nm. The measurement on the compound-P1 is not reported as there is no detectable nonlinear response. Open aperture data of the other three compounds indicate two photon absorption at this wavelength. The nonlinear refractive index n2, nonlinear absorption coefficient β, magnitude of effective third order susceptibility χ(3), the second order hyperpolarizability γh and the coupling factor ρ have been estimated. The values obtained are comparable with the values obtained for 4-methoxy chalcone derivatives and dibenzylideneacetone derivatives. The experimentally determined values of β, n2, Re χ(3) and Im χ(3), γh and ρ of the compound-P4 are 1.42 cm/GW, -0.619 × 10-11 esu, -0.663 × 10-13 esu, 0.22 × 10-13 esu, 0.34 × 10-32 esu and 0.33 respectively. Further the compound-P4 exhibited the best optical power limiting behavior at 532 nm among the compounds studied. Our studies suggest that compounds P2, P3 and P4 are potential candidates for the optical device applications such as optical limiters and optical switches.

  13. Study of Optical Mode Scrambling of Fiber Optics for High Precision Radial Velocity Measurements

    NASA Astrophysics Data System (ADS)

    Cassette, Anthony; Ge, Jian; Jeram, Sarik; Klanot, Khaya; Ma, Bo; Varosi, Frank

    2016-01-01

    Optical Fibers have been used throughout Astronomy for spectroscopy with spectrographs located some distance away from the telescope. This fiber-fed design has greatly increased precision for radial velocity (RV) measurements. However, due to the incomplete fiber illumination mode scrambling in the radial direction, high resolution spectrographs with regular circular fibers have suffered RV uncertainties on the order of a few to tens of m/s with stellar observations, which largely limited their sensitivity in detecting and characterizing low mass planets around stars. At the University of Florida, we studied mode scrambling gain of a few different optical devices, such as three-lens optical double scramblers, octagonal fibers and low numerical aperture fibers with a goal to find an optimal mode scrambling solution for the TOU optical very high resolution spectrograph (R=100,000, 0.38-0.9 microns) and FIRST near infrared high resolution spectrograph (R=60,000, 0.9-1.8 microns) for the on-going Dharma Planet Survey. This presentation will report our lab measurement results and also stellar RV measurements at the observatories.

  14. Towards femtosecond laser surgery guidance in the posterior eye: utilization of optical coherence tomography and adaptive optics for focus positioning and shaping

    NASA Astrophysics Data System (ADS)

    Krüger, Alexander; Hansen, Anja; Matthias, Ben; Ripken, Tammo

    2014-02-01

    Although fs-laser surgery is clinically established in the field of corneal flap cutting for laser in situ keratomileusis, surgery with fs-laser in the posterior part of the eye is impaired by focus degradation due to aberrations. Precise targeting and keeping of safety distance to the retina also relies on an intraoperative depth resolved imaging. We demonstrate a concept for image guided fs-laser surgery in the vitreous body combining adaptive optics (AO) for focus reshaping and optical coherence tomography (OCT) for focus position guidance. The setup of the laboratory system consist of an 800 nm fs-laser which is focused into a simple eye model via a closed loop adaptive optics system with Hartmann-Shack sensor and a deformable mirror to correct for wavefront aberrations. A spectral domain optical coherence tomography system is used to target phantom structures in the eye model. Both systems are set up to share the same scanner and focusing optics. The use of adaptive optics results in a lowered threshold energy for laser induced breakdown and an increased cutting precision. 3D OCT imaging of porcine retinal tissue prior and immediately after fs-laser cutting is also demonstrated. In the near future OCT and AO will be two essential assistive components in possible clinical systems for fs-laser based eye surgery beyond the cornea.

  15. 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…

  16. A Optical Study of Defects in Diamond.

    NASA Astrophysics Data System (ADS)

    Beard, Darren R.

    Available from UMI in association with The British Library. The one-phonon defect-induced infrared absorption in Type I diamonds has been studied. The previously reported spectral forms of the F and G spectra have been altered. Three components labelled J, K and L, are presented. A data base of 75 infrared spectra has been decomposed and classified. New computer programs have been produced to cope with up to 12 components in the one-phonon region simultaneously. Black diamond surfaces have been examined using photoluminescence spectroscopy. Laser cutting in air is found to result in black surfaces. Diamonds were examined both before and after cutting and changes in the spectra monitored. In Type Ib and Type IIb diamonds, the typical diamond spectrum was changed into a broad band spectrum. The first order diamond Raman was not detectable after laser cutting. Type Ia and Type IIa diamonds did not show any changes due to being cut. To investigate the graphitization process further, diamonds were heated to 850^circC in gas flows at 0.38 torr (50.7 Pa). Using oxygen, it was found that the intensity of H3 luminescence was reduced and that a broad band spectrum was produced. The spectral changes were reversed by treating with hydrogen. Two types of thin carbonaceous films have been examined, those grown by vapour deposition and those produced by scanning a high energy density laser beam across an amorphous carbon sample. The photoluminescence spectra obtained from the two sample types were different. Discs of sintered diamond have also been examined with a view to determining the strain distribution within the samples. Finally, the production mechanism of the H3 defect has been considered. A grown-in theory is developed. It is supported quantitatively with experimental results and explains the ubiquity of H3, even in synthetic crystals. The C centre is thought to be incorporated equally on all of the low index faces of diamond. Consideration of the A centre showed that it

  17. Versatile transmission ellipsometry to study linear ferrofluid magneto-optics.

    PubMed

    Kooij, E S; Gâlcă, A C; Poelsema, B

    2006-12-01

    Linear birefringence and dichroism of magnetite ferrofluids are studied simultaneously using spectroscopic ellipsometry in transmission mode. It is shown that this versatile technique enables highly accurate characterisation of magneto-optical phenomena. Magnetic field-dependent linear birefringence and dichroism as well as the spectral dependence are shown to be in line with previous results. Despite the qualitative agreement with established models for magneto-optical phenomena, these fail to provide an accurate, quantitative description of our experimental results using the bulk dielectric function of magnetite. We discuss the results in relation to these models, and indicate how the modified dielectric function of the magnetite nanoparticles can be obtained. PMID:16997315

  18. Infrared study of γ irradiated fluoride optical fibers

    NASA Astrophysics Data System (ADS)

    Abgrall, A.; Poulain, M.; Boisde, G.; Cardin, V.; Maze, G.

    1986-05-01

    In order to develop infrared optical fiber systems in nuclear media, studies are made to know the behavior on line of fluoride glass optical fibers under irradiation. the increase of induced loss and the influence of the dose rate are given at 2.4 microns. Cycles of rela-xation at room temperature and y ray exposure allows an important bleaching and an unaffected kinetic of losses. Characterization of defects created by y radiation on bulk of ZBLA glass is carried out by means of electron spin resonance (ESR). A linear kinetic of ESR signal with dose is observed and possible models for defects are discussed.

  19. Comprehensive study on the concept of temporal optical waveguides

    NASA Astrophysics Data System (ADS)

    Zhou, Junhe; Zheng, Guozeng; Wu, Jianjie

    2016-06-01

    Time and space are dual variables which bring a lot of analogies during theoretical study. In this paper, we extend the concept of a spatial optical waveguide to the temporal domain. Here we show that it is possible to confine the optical pulse within a time interval by introducing the temporal index boundaries. The confined pulse will propagate at a speed of the index change in the waveguide, and it will be behind the original optical pulse which propagates without the temporal index variations. In this way, we may offer an approach to broaden the bandwidth of the slow light and to tune the light speed based on the existing slow light devices. The temporal waveguide has modes, which are the temporal waveforms maintaining their shapes during the propagation. In a single-mode temporal waveguide, the pulse retains its shape as the only mode of the waveguide just like an optical soliton. In a multimode temporal waveguide, multimode interference effect exists, which can duplicate a single pulse into multiple copies and be potentially implemented for all-optical signal processing.

  20. 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.

  1. 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)

  2. 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

  3. Optical studies of high-temperature superconducting cuprates.

    PubMed

    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. PMID:27472654

  4. Advanced studies on the Polycapillary Optics use at XLab Frascati

    NASA Astrophysics Data System (ADS)

    Hampai, D.; Dabagov, S. B.; Cappuccio, G.

    2015-07-01

    X-ray analytical techniques are widely used in the world. By the way, due to the strong radiation-matter interaction, to design optical devices suitable for X-ray radiation remains still of wide interest. As a consequence of novel advanced material studies, in the last 30 years several typologies of X-ray lenses have been developed. In this work, a short review on the status of Polycapillary Optics (polyCO), from design and fabrication to various applications, has been presented making comparison of the results achieved by several groups through different X-ray optical elements. A focus is regarded for advanced X-ray imaging and spectroscopy tools based on combination of the modern polyCO hardware and the reconstruction software, available as homemade and commercially ones. Recent results (in three main fields, high resolution X-ray imaging, micro-XRF spectroscopy and micro-tomography) obtained at XLab Frascati have been discussed.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. A Study About Improvement of Efficiency of a Sewage Heat Utilization System

    NASA Astrophysics Data System (ADS)

    Kobayakawa, Tomoaki; Hihara, Eiji; Hanazaki, Hirotaka

    In order to acquire the basis of technical information that will be required for the design and operation of a sewage heat utilization system, this paper discusses the data analysis of operational performance at the DHC plant in Makuhari HB area. The methodology used in this study is to clarify the characteristics of a sewage heat utilization system from compound characteristics of the DHC plant that consists of various heating systems, and evaluate them.

  10. Studying wave optics in the light curves of exoplanet microlensing

    NASA Astrophysics Data System (ADS)

    Mehrabi, Ahmad; Rahvar, Sohrab

    2013-05-01

    We study the wave optics features of gravitational microlensing by a binary lens composed of a planet and a parent star. In this system, the source star near the caustic line produces a pair of images in which they can play the role of secondary sources for the observer. This optical system is similar to the Young double-slit experiment. The coherent wavefronts from a source on the lens plane can form a diffraction pattern on the observer plane. This diffraction pattern has two modes from the close- and wide-pair images. From the observational point of view, we study the possibility of detecting this effect through the Square Kilometre Array (SKA) project in the resonance and high-magnification channels of binary lensing. While the red giant sources do not seem to satisfy the spatial coherency condition, during the caustic crossing a small part of a source traversing the caustic line can produce coherent pair images. Observations of wave optics effects at longer wavelengths accompanied by optical observations of a microlensing event provide extra information on the parameter space of the planet. These observations can provide a new basis for the study of exoplanets.

  11. Electro-optic MZI modulators, utilizing different phases in proton-exchanged LiTaO3 waveguides

    NASA Astrophysics Data System (ADS)

    Kostritskii, S. M.; Korkishko, Yu. N.; Fedorov, V. A.; Tavlykaev, R. F.; Ramaswamy, R. V.

    2005-09-01

    Electro-optic Mach-Zehnder interferometric (MZI) modulators have been fabricated by proton exchange in LiTaO3. Electro-optic efficiency of these modulators has been found to be depending on phase composition of HxLi1-xTaO3 waveguide in full accordance with the data of Raman scattering spectroscopy on microscopic contributions in electro-optic effect for the different HxLi1-xTaO3 phases. These spectroscopy data were used to found an appropriate phase composition and, thus, optimize MZI modulators. The experimental samples of MZI modulator fabricated at the optimal technological conditions exhibit the improved electro-optical efficiency with far superior photorefractive resistance compared to the LiNbO3 waveguides and modulators.

  12. 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.; Glesne, T.

    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

  13. 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

  14. 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.

  15. A Genome-Wide Association Study of Optic Disc Parameters

    PubMed Central

    Jansonius, Nomdo M.; de Jong, Paulus T. V. M.; Bergen, Arthur A. B.; Isaacs, Aaron; Amin, Najaf; Aulchenko, Yurii S.; Wolfs, Roger C. W.; Hofman, Albert; Rivadeneira, Fernando; Oostra, Ben A.; Uitterlinden, Andre G.; Hysi, Pirro; Hammond, Christopher J.; Lemij, Hans G.; Vingerling, Johannes R.

    2010-01-01

    The optic nerve head is involved in many ophthalmic disorders, including common diseases such as myopia and open-angle glaucoma. Two of the most important parameters are the size of the optic disc area and the vertical cup-disc ratio (VCDR). Both are highly heritable but genetically largely undetermined. We performed a meta-analysis of genome-wide association (GWA) data to identify genetic variants associated with optic disc area and VCDR. The gene discovery included 7,360 unrelated individuals from the population-based Rotterdam Study I and Rotterdam Study II cohorts. These cohorts revealed two genome-wide significant loci for optic disc area, rs1192415 on chromosome 1p22 (p = 6.72×10−19) within 117 kb of the CDC7 gene and rs1900004 on chromosome 10q21.3-q22.1 (p = 2.67×10−33) within 10 kb of the ATOH7 gene. They revealed two genome-wide significant loci for VCDR, rs1063192 on chromosome 9p21 (p = 6.15×10−11) in the CDKN2B gene and rs10483727 on chromosome 14q22.3-q23 (p = 2.93×10−10) within 40 kbp of the SIX1 gene. Findings were replicated in two independent Dutch cohorts (Rotterdam Study III and Erasmus Rucphen Family study; N = 3,612), and the TwinsUK cohort (N = 843). Meta-analysis with the replication cohorts confirmed the four loci and revealed a third locus at 16q12.1 associated with optic disc area, and four other loci at 11q13, 13q13, 17q23 (borderline significant), and 22q12.1 for VCDR. ATOH7 was also associated with VCDR independent of optic disc area. Three of the loci were marginally associated with open-angle glaucoma. The protein pathways in which the loci of optic disc area are involved overlap with those identified for VCDR, suggesting a common genetic origin. PMID:20548946

  16. Electron paramagnetic resonance and optical absorption spectral studies on chalcocite

    NASA Astrophysics Data System (ADS)

    Reddy, S. Lakshmi; Fayazuddin, Md.; Frost, Ray L.; Endo, Tamio

    2007-11-01

    A chalcocite mineral sample of Shaha, Congo is used in the present study. An electron paramagnetic resonance (EPR) study on powdered sample confirms the presence of Mn(II), Fe(III) and Cu(II). Optical absorption spectrum indicates that Fe(III) impurity is present in octahedral structure whereas Cu(II) is present in rhombically distorted octahedral environment. Mid-infrared results are due to water and sulphate fundamentals.

  17. Electron paramagnetic resonance and optical absorption spectral studies on chalcocite.

    PubMed

    Reddy, S Lakshmi; Fayazuddin, Md; Frost, Ray L; Endo, Tamio

    2007-11-01

    A chalcocite mineral sample of Shaha, Congo is used in the present study. An electron paramagnetic resonance (EPR) study on powdered sample confirms the presence of Mn(II), Fe(III) and Cu(II). Optical absorption spectrum indicates that Fe(III) impurity is present in octahedral structure whereas Cu(II) is present in rhombically distorted octahedral environment. Mid-infrared results are due to water and sulphate fundamentals. PMID:17324611

  18. Optical emission studies of reactive species in plasma deposition

    SciTech Connect

    Kampas, F.J.; Griffith, R.W.

    1981-01-01

    Optical emission studies of the glow-discharge deposition of a-Si:H alloys reveal the presence of reactive species derived from process gases and impurities. Studies of the dependences of emission intensities upon deposition parameters elucidate the mechanisms of formation of these species. Effects of impurities detected by emission spectroscopy upon a-Si:H film electronic properties are discussed. A model of the chemical reactions involved in film growth is presented.

  19. 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.

  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

    2017-01-01

    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

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. Electrically switchable polymer liquid crystal and polymer birefringent flake in fluid host systems and optical devices utilizing same

    SciTech Connect

    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.

  7. 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. PMID:23670767

  8. Optical activity in planar chiral metamaterials: Theoretical study

    SciTech Connect

    Bai, Benfeng; Svirko, Yuri; Turunen, Jari; Vallius, Tuomas

    2007-08-15

    A thorough theoretical study of the optical activity in planar chiral metamaterial (PCM) structures, made of both dielectric and metallic media, is conducted by the analysis of gammadion-shaped nanoparticle arrays. The general polarization properties are first analyzed from an effective-medium perspective, by analogy with natural optical activity, and then verified by rigorous numerical simulation, some of which are corroborated by previous experimental results. The numerical analysis suggests that giant polarization rotation (tens of degrees) may be achieved in the PCM structures with a thickness of only hundreds of nanometers. The artificial optical activity arises from circular birefringence induced by the structural chirality and is enhanced by the guided-mode or surface-plasmon resonances taking place in the structures. There are two polarization conversion types in the dielectric PCMs, whereas only one type in the metallic ones. Many intriguing features of the polarization property of PCMs are also revealed and explained: the polarization effect is reciprocal and vanishes in the symmetrically layered structures; the effect occurs only in the transmitted field, but not in the reflected field; and the polarization spectra of two enantiomeric PCM structures are mirror symmetric to each other. These remarkable properties pave the way for the PCMs to be used as polarization elements in new-generation integrated optical systems.

  9. A multitechnique study of bacteriorhodopsin's photonics toward new optical devices

    NASA Astrophysics Data System (ADS)

    Martin, Marta; Saab, Marie-Belle; Cloitre, Thierry; Estephan, Elias; Legros, René; Cuisinier, Frédéric J. G.; Zimányi, László; Gergely, Csilla

    2008-04-01

    Bacteriorhodopsin (BR) is a robust trans-membrane protein that functions as a light-driven proton pump, thus is an excellent candidate for biophotonics applications. For the development of new optical devices, the buildup of stable BR matrices has to be optimised. In this work, we present a multi- technique approach: the combination of optical waveguide lightmode spectroscopy (OWLS), atomic force microscopy (AFM) and multi-photon microscopy (MPM) aiming to analyze the optical and physico-chemical properties of BR embedded in polyelectrolyte multilayers (PEM) in its membrane bound form (purple membrane, PM), as well as solubilized BR immobilized within a photonic structure built of porous silicon (PSi). OWLS measurements revealed the possibility of incorporation of PM-BR layers into PE-multilayers. The calculated thickness and refractive index of the adsorbed layers demonstrate the successful adsorption of PM on top of the positively or negatively charged PE layers. Morphological studies by AFM proved a complete coverage of the positively charged PE layer with PM patches. As for the other model system, photonic responses of BR, after being immobilized within PSi substrates, have been evaluated using multi-photon microscopy. Fluorescence emission and second harmonic generation (SHG) of the BR-PSi system were observed at some particular pores of PSi and subsequent enhancement of the signal arising from the BR adsorbed within the pores was detected. Our results constitute the first steps of two interesting and innovative biomimetic approaches for the future design and development of BR based integrated optical devices.

  10. Fiber-optic sensors for acoustic studies and biological applications

    NASA Astrophysics Data System (ADS)

    Zhou, Chonghua

    1997-11-01

    This study is directed at the investigation of the applicability of various fiber-optic techniques in acoustic studies and biological sensing. The acoustic studies are conducted both at low frequencies, such as in audible sound and dynamic wave propagation measurements, and at high frequencies, such as in ultrasound for nondestructive evaluation. In biological sensing, an all- fiber-optic design biosensor with evanescent-mode coupling has been implemented and an enhanced biosensor using ultrasonic localization has been studied. The type of sensor considered for audible sound measurement is based on a combination of Fabry-Perot interferometry and intensity modulation. The technique provides information on both the amplitude and direction of the vibration and thus removes fringe counting ambiguity over a wide dynamic range, and still keeps the high-sensitivity property of interferometry. A novel microbend fiber-optic strain sensor was developed and applied to static and dynamic fracture problems and dynamic wave propagation studies. Static and dynamic fracture experiments and dynamic impact experiment have been performed and the results match well with the theoretical predications and the results obtained with electrical strain gages. The application of polarimetric fiber-optic ultrasonic sensors in nondestructive evaluation of materials is also presented. Theoretical analysis and experimental optimization have been performed and both immersion testing and embedding testing of internal defects of materials have been conducted and promising results have been obtained. For biological application, a compact fiber-optic evanescent-wave sensing system with all-fiber optical design and red semiconductor-laser excitation has been developed and tested. In this system, the fluorescent signal is confined in the fiber system so the signal-to- noise ratio is greatly improved and the sensor can be operated in ambient light conditions. To further enhance this biosensor, an

  11. The emerging use of in vivo optical imaging in the study of neurodegenerative diseases.

    PubMed

    Patterson, Aileen P; Booth, Stephanie A; Saba, Reuben

    2014-01-01

    The detection and subsequent quantification of photons emitted from living tissues, using highly sensitive charged-couple device (CCD) cameras, have enabled investigators to noninvasively examine the intricate dynamics of molecular reactions in wide assortment of experimental animals under basal and pathophysiological conditions. Nevertheless, extrapolation of this in vivo optical imaging technology to the study of the mammalian brain and related neurodegenerative conditions is still in its infancy. In this review, we introduce the reader to the emerging use of in vivo optical imaging in the study of neurodegenerative diseases. We highlight the current instrumentation that is available and reporter molecules (fluorescent and bioluminescent) that are commonly used. Moreover, we examine how in vivo optical imaging using transgenic reporter mice has provided new insights into Alzheimer's disease, amyotrophic lateral sclerosis (ALS), Prion disease, and neuronal damage arising from excitotoxicity and inflammation. Furthermore, we also touch upon studies that have utilized these technologies for the development of therapeutic strategies for neurodegenerative conditions that afflict humans. PMID:25147799

  12. The Emerging Use of In Vivo Optical Imaging in the Study of Neurodegenerative Diseases

    PubMed Central

    Booth, Stephanie A.; Saba, Reuben

    2014-01-01

    The detection and subsequent quantification of photons emitted from living tissues, using highly sensitive charged-couple device (CCD) cameras, have enabled investigators to noninvasively examine the intricate dynamics of molecular reactions in wide assortment of experimental animals under basal and pathophysiological conditions. Nevertheless, extrapolation of this in vivo optical imaging technology to the study of the mammalian brain and related neurodegenerative conditions is still in its infancy. In this review, we introduce the reader to the emerging use of in vivo optical imaging in the study of neurodegenerative diseases. We highlight the current instrumentation that is available and reporter molecules (fluorescent and bioluminescent) that are commonly used. Moreover, we examine how in vivo optical imaging using transgenic reporter mice has provided new insights into Alzheimer's disease, amyotrophic lateral sclerosis (ALS), Prion disease, and neuronal damage arising from excitotoxicity and inflammation. Furthermore, we also touch upon studies that have utilized these technologies for the development of therapeutic strategies for neurodegenerative conditions that afflict humans. PMID:25147799

  13. 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.

  14. Design study for supporting of thin glass optical elements for x-ray telescopes

    NASA Astrophysics Data System (ADS)

    Freeman, Mark D.; Reid, Paul B.; Davis, William N.

    2008-07-01

    The next large x-ray astrophysics mission launched will likely include soft x-ray spectroscopy as a primary capability. A requirement to fulfill the science goals of such a mission is a large-area x-ray telescope focusing sufficient x-ray flux to perform high-resolution spectroscopy with reasonable observing times. One approach to manufacturing such a telescope is a Wolter-I optic utilizing thin glass segments rather than full shells of revolution. We describe a parameterized Finite Element Modeling (FEM) study that provides insights useful in optimizing the design of a discrete support system to balance the competing requirements of minimizing the effect on optical performance while providing sufficient support to withstand launch loads. Parameters analyzed are number and location of the supports around the glass segments, as well as the glass thickness, size, and angular span. In addition, we utilize more detailed models of several cases taken from the parametric study to examine stress around the bonded area and bond pad size, and compare the stress from the detailed model to the parametric cases from which they were derived.

  15. Accuracy of optical dental digitizers: an in vitro study.

    PubMed

    Vandeweghe, Stefan; Vervack, Valentin; Vanhove, Christian; Dierens, Melissa; Jimbo, Ryo; De Bruyn, Hugo

    2015-01-01

    The aim of this study was to evaluate the accuracy, in terms of trueness and precision, of optical dental scanners. An experimental acrylic resin cast was created and digitized using a microcomputed tomography (microCT) scanner, which served as the reference model. Five polyether impressions were made of the acrylic resin cast to create five stone casts. Each dental digitizer (Imetric, Lava ST, Smart Optics, KaVo Everest) made five scans of the acrylic resin cast and one scan of every stone cast. The scans were superimposed and compared using metrology software. Deviations were calculated between the datasets obtained from the dental digitizers and the microCT scanner (= trueness) and between datasets from the same dental digitizer (= precision). With exception of the Smart Optics scanner, there were no significant differences in trueness for the acrylic resin cast. For the stone casts, however, the Lava ST performed better than Imetric, which did better than the KaVo scanner. The Smart Optics scanner demonstrated the highest deviation. All digitizers demonstrated a significantly higher trueness for the acrylic resin cast compared to the plaster cast, except the Lava ST. The Lava ST was significantly more precise compared to the other scanners. Imetric and Smart Optics also demonstrated a higher level of precision compared to the KaVo scanner. All digitizers demonstrated some degree of error. Stone cast copies are less accurate because of difficulties with scanning the rougher surface or dimensional deformations caused during the production process. For complex, large-span reconstructions, a highly accurate scanner should be selected. PMID:25734714

  16. 26 Tbit s-1 line-rate super-channel transmission utilizing all-optical fast Fourier transform processing

    NASA Astrophysics Data System (ADS)

    Hillerkuss, D.; Schmogrow, R.; Schellinger, T.; Jordan, M.; Winter, M.; Huber, G.; Vallaitis, T.; Bonk, R.; Kleinow, P.; Frey, F.; Roeger, M.; Koenig, S.; Ludwig, A.; Marculescu, A.; Li, J.; Hoh, M.; Dreschmann, M.; Meyer, J.; Ben Ezra, S.; Narkiss, N.; Nebendahl, B.; Parmigiani, F.; Petropoulos, P.; Resan, B.; Oehler, A.; Weingarten, K.; Ellermeyer, T.; Lutz, J.; Moeller, M.; Huebner, M.; Becker, J.; Koos, C.; Freude, W.; Leuthold, J.

    2011-06-01

    Optical transmission systems with terabit per second (Tbit s-1) single-channel line rates no longer seem to be too far-fetched. New services such as cloud computing, three-dimensional high-definition television and virtual-reality applications require unprecedented optical channel bandwidths. These high-capacity optical channels, however, are fed from lower-bitrate signals. The question then is whether the lower-bitrate tributary information can viably, energy-efficiently and effortlessly be encoded to and extracted from terabit per second data streams. We demonstrate an optical fast Fourier transform scheme that provides the necessary computing power to encode lower-bitrate tributaries into 10.8 and 26.0 Tbit s-1 line-rate orthogonal frequency-division multiplexing (OFDM) data streams and to decode them from fibre-transmitted OFDM data streams. Experiments show the feasibility and ease of handling terabit per second data with low energy consumption. To the best of our knowledge, this is the largest line rate ever encoded onto a single light source.

  17. A study of aerosol optical properties at the global GAW station Bukit Kototabang, Sumatra, Indonesia

    NASA Astrophysics Data System (ADS)

    Nurhayati, N.; Nakajima, Teruyuki

    2012-01-01

    There have been very few studies carried out in Indonesia on the atmospheric aerosol optical properties and their impact on the earth climate. This study utilized solar radiation and aerosol measurement results of Indonesian GAW station Bukit Kototabang in Sumatra. The radiation data of nine years were used as input to a radiation simulation code for retrieving optically equivalent parameters of aerosols, i.e., aerosol optical thickness (AOT), coarse particle to fine particle ratio ( γ-ratio), and soot fraction. Retrieval of aerosol properties shows that coarse particles dominated at the station due to high relative humidity (RH) reaching more than 80% throughout the year. AOT time series showed a distinct two peak structure with peaks in MJJ and NDJ periods. The second peak corresponds to the period of high RH suggesting it was formed by active particle growth with large RH near 90%. On the other hand the time series of hot spot number, though it is only for the year of 2004, suggests the first peak was strongly contributed by biomass burning aerosols. The γ-ratio took a value near 10 throughout the year except for November and December when it took a larger value. The soot fraction varies in close relation with the γ-ratio, i.e. low values when γ was large, as consistent with our proposal of active particle growth in the high relative periods.

  18. Polished substrate surface and cleaning study for coated optic quality

    SciTech Connect

    Tesar, A.; Eickelberg, W.; Koons, K.; Davis, K.

    1992-11-01

    The optical substrate-coating interface is established by (1) the original polished condition of the substrate; (2) the substrate cleaning process; and (3) the environment of the coating process. The substrate-coating interface affects the coating adhesion properties, is where most coating defects and scatter sites are thought to initiate, and in some instances may control the structure of the coating as it is deposited. Often features appear on an optic after coating which could not be observed after cleaning and prior to coating. Because of the wide variety of possible substrate materials, surface problems, and contaminants, cleaning processes are constantly evolving. Our study has clearly shown that the coating appearance is dependent not only on the cleaning method, but especially on the initial character of the substrate surface.

  19. 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.

  20. 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.

  1. 100 ps time-resolved solution scattering utilizing a wide-bandwidth X-ray beam from multilayer optics.

    PubMed

    Ichiyanagi, K; Sato, T; Nozawa, S; Kim, K H; Lee, J H; Choi, J; Tomita, A; Ichikawa, H; Adachi, S; Ihee, H; Koshihara, S

    2009-05-01

    100 ps time-resolved X-ray solution-scattering capabilities have been developed using multilayer optics at the beamline NW14A, Photon Factory Advanced Ring, KEK. X-ray pulses with an energy bandwidth of DeltaE/E = 1-5% are generated by reflecting X-ray pulses (DeltaE/E = 15%) through multilayer optics, made of W/B(4)C or depth-graded Ru/C on silicon substrate. This tailor-made wide-bandwidth X-ray pulse provides high-quality solution-scattering data for obtaining photo-induced molecular reaction dynamics. The time-resolved solution scattering of CH(2)I(2) in methanol is demonstrated as a typical example. PMID:19395804

  2. Linking Resource Allocation to Student Achievement: A Study of Title 1 and Title 1 Stimulus Utilization

    ERIC Educational Resources Information Center

    Krumpe, Kati P.

    2012-01-01

    With the emphasis on high standards and fiscal accountability, there is a heightened need to inform the research linking student achievement to the allocation of resources. This mixed methods inquiry sought to study how schools utilized Title 1 and Title 1 stimulus funding from 2009-2011 to determine if correlations existed between areas of…

  3. PROSPECTIVE EPIDEMIOLOGICAL STUDY OF HEALTH RISKS ASSOCIATED WITH WASTEWATER UTILIZATION IN AGRICULTURE (JOURNAL VERSION)

    EPA Science Inventory

    A prospective epidemiological morbidity and serology study was carried out in Israel in 1980/82 on the association between enteric disease incidence and wastewater utilization in 29 kibbutzim. Analysis of morbidity data indicate that no significant excess of enteric disease episo...

  4. The Effect of Persuasion on the Utilization of Program Evaluation Information: A Preliminary Study.

    ERIC Educational Resources Information Center

    Eason, Sandra H.; Thompson, Bruce

    The utilization of program evaluation may be made more effective by means of the application of contemporary persuasion theory. The Elaboration Likelihood Model--a model of cognitive processing, ability, and motivation--was used in this study to test the persuasive effects of source credibility and involvement on message acceptance of evaluation…

  5. A Study on the Selection and Utilization of MEDLINE Search Systems.

    ERIC Educational Resources Information Center

    Bader, Shelley A.; Piemme, Thomas E.

    This report presents the objectives, methodology, and results of a study which assessed the selection and utilization of four MEDLINE search systems by faculty and medical residents at the George Washington University Medical Center. The four systems, which were provided or sponsored by the Himmelfarb Health Sciences Library, offer a wide range of…

  6. 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…

  7. THE CURRENT STATUS OF THE ELECTRIC UTILITY INDUSTRY IN THE OHIO RIVER BASIN ENERGY STUDY STATES

    EPA Science Inventory

    The report was prepared as part of the Ohio River Basin Energy Study (ORBES), a multidisciplinary policy research program. It reviews the status of the electric utility industry in the six ORBES states: Illinois, Indiana, Kentucky, Ohio, Pennsylvania, and West Virginia. Topics in...

  8. Utility of Interactional Strategies in the Study of Formal Operations Reasoning.

    ERIC Educational Resources Information Center

    Siegler, Robert S.

    This paper argues in favor of using interactional strategies in the study of formal operations reasoning. Interactional designs allow a convergent approach to specifying processes underlying the interaction of variables. In contrast, current methodologies contain two inherent disadvantages: they have limited utility in specifying the processes…

  9. 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...

  10. Classroom Utilization of Ancillary Personnel: Delivery Systems for Mainstreaming in Elementary Social Studies.

    ERIC Educational Resources Information Center

    Rockoff, Edward

    1979-01-01

    Proposes in-service training on the utilization of ancillary personnel (special education teacher, school nurse, hearing and speech clinician, guidance counselor) in assisting the social studies teacher with the mainstreamed student. Outlines how ancillary personnel may aid in preparing students for entrance into the regular classroom, developing…

  11. 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.

  12. Parametric study and optimization of a micro-optical switch with a laterally driven electromagnetic microactuator

    NASA Astrophysics Data System (ADS)

    Han, Jeong Sam; Ko, Jong Soo; Kim, Youn Tae; Kwak, Byung Man

    2002-11-01

    In this paper we present an in-depth parametric study and structural optimization for a micro-optical switch based on the concept of a laterally driven electromagnetic microactuator (LaDEM). This utilizes the nonlinear behavior of a snap-through buckling occurring in two arch-shaped leaf springs of the switch, when actuated by a distributed Lorentz force induced along the leaf springs. A sudden jump in displacement can facilitate a large actuation stroke suitable for practical applications. The leaf springs are connected to the fixed frame with two meandering parts, which also enhance their flexibility. Thus, an important objective in the design of the micro-optical switch is to achieve a large displacement with low actuation force. For this purpose, the effect of important geometrical parameters, such as the initial height of the leaf spring and the dimensions of meandering part on the displacement response is first investigated and optimized to satisfy given design specifications. The nonlinear displacement-load response calculated by a modified Riks method in ABAQUS shows good agreement with the measurement result. Nonlinear finite element techniques and optimizations are found to be valuable tools for the analysis and design of microactuators, which utilize a complex nonlinear snap-through buckling behavior.

  13. Embracing Uncertainty: A Case Study Examination of How Climate Change is Shifting Water Utility Planning

    NASA Astrophysics Data System (ADS)

    Kaatz, L.

    2015-12-01

    Climate change has emerged as one of the greatest challenges facing water utilities' planning for the future, adding a new source and level of complexity that is forcing many agencies to re-examine their decision-making processes. A significant barrier for many agencies is figuring out how to consider highly uncertain climate information and move away from deterministic thinking to make climate-informed decisions. To provide water professionals with practical and relevant information, the Water Utility Climate Alliance teamed up with the American Water Works Association, in coordination with the Water Research Foundation and Association of Metropolitan Water Agencies, to develop a white paper sharing insights into how and why water agencies are modifying planning and decision-making processes. The 13 case studies presented illustrate the variety of ways in which utilities are incorporating climate change into planning, from immediate operational decisions, to capital planning and asset management, to long-term supply planning.

  14. Study of an incremental optical encoder using speckle

    NASA Astrophysics Data System (ADS)

    Perez Quintián, Fernando; Lutenberg, Ariel; Rebollo, María Aurora

    2006-09-01

    We present a study of the performance of an incremental optical encoder that works using speckle pattern illumination and a phase grating. The operational principle of the encoder lies in measuring the variations of a speckle pattern passing through the phase grating that can be displaced. This study is described theoretically by a model based on the scalar diffraction theory in the Fresnel zone. The intensity correlation of the modified speckle as a function of the grating displacement is obtained and compared with experimental results. Likewise, the mounting tolerances of the proposed system are analyzed.

  15. A new apparatus for studying quantum gases in optical lattices

    NASA Astrophysics Data System (ADS)

    Schneider, Ulrich; Duca, Lucia; Li, Tracy; Boll, Martin; Ronzheimer, Philipp; Braun, Simon; Will, Sebastian; Rom, Tim; Schreiber, Michael; Bloch, Immanuel

    2011-05-01

    We present the design of a new apparatus targeted at the study of equilibrium and out-of-equilibrium phenomena of quantum gases in 2D and 3D optical lattices. Specifically this apparatus will allow for a study of the crossover between 2D and 3D using bosonic and fermionic gases as well as Bose-Fermi mixtures. In addition we present a new analysis of previous results concerning the Fermi-Hubbard model and will analyze possible routes for creating many-body states with long range order, including antiferromagnetically ordered states and BCS-superfluids. This work is supported by DARPA/OLE MURI DFG MPQ.

  16. Optic Nerve Dysfunction in Obstructive Sleep Apnea: An Electrophysiological Study

    PubMed Central

    Liguori, Claudio; Palmieri, Maria Giuseppina; Pierantozzi, Mariangela; Cesareo, Massimo; Romigi, Andrea; Izzi, Francesca; Marciani, Maria Grazia; Oliva, Corrado; Mercuri, Nicola Biagio; Placidi, Fabio

    2016-01-01

    Study Objectives: The aim of this study was to evaluate the integrity of the visual system in patients affected by obstructive sleep apnea (OSA) by means of electroretinogram (ERG) and visual evoked potential (VEP). Methods: We performed electrophysiological study of the visual system in a population of severe OSA (apnea-hypopnea events/time in bed ≥ 30/h) patients without medical comorbidities compared to a group of healthy controls similar for age, sex, and body mass index. Patients and controls did not have visual impairment or systemic disorders with known influence on the visual system. ERG and VEP were elicited by a reversal pattern generated on a television monitor at low (55') and high (15') spatial frequencies stimulation. Daytime sleepiness was assessed using the Epworth Sleepiness Scale (ESS) in both patients and controls. Results: In comparison with healthy controls (n = 27), patients with OSA (n = 27) showed a significant latency delay coupled with a significant amplitude reduction of P100 wave of VEP at all spatial frequencies in both eyes. No significant differences between groups were detected as concerning ERG components. No correlations were found between polygraphic parameters, ESS scores, or VEP and ERG components in OSA patients. Conclusions: This study documented that patients with OSA, without medical comorbidities, present VEP alteration as documented by lower amplitude and longer latency of the P100 component than healthy controls. These altered electrophysiological findings may be the expression of optic nerve dysfunction provoked by hypoxia, acidosis, hypercarbia and airway obstruction, frequently observed in patients with OSA. Hence, we hypothesize that OSA per se may impair optic nerve function. Citation: Liguori C, Palmieri MG, Pierantozzi M, Cesareo M, Romigi A, Izzi F, Marciani MG, Oliva C, Mercuri NB, Placidi F. Optic nerve dysfunction in obstructive sleep apnea: an electrophysiological study. SLEEP 2016;39(1):19–23. PMID

  17. Ultrafast optical studies of surface reaction processes at semiconductor interfaces

    SciTech Connect

    Miller, R.J.D.

    1993-03-01

    Rectifying properties of semiconductor liquid junctions make them a simple system for converting and storing optical energy. However, interfacial electron or hole carrier transfer and competing non-radiative (energy loss) channels are not well understood at surfaces. This research has explored the use of three optical techniques, Surface Space Charge Electrooptic Sampling, Surface Restricted Transient Grating Spectroscopy, and Femtosecond Optical Kerr Spectroscopy (OKE) to obtain time evolution of the surface spatial distribution of photogenerated charge carriers, photocarrier population dynamics at semiconductor interfaces, and solvent modes responsible for charge localization and separation. These studies have shown that carriers arrive at GaAs(100) surfaces on the hundred femtosecond time scale. Improvements in time resolution, using surface grating spectroscopy, have shown interfacial hole transfer is occurring on the picosecond time scale. The OKE approach to solvent dynamics has determined the response of water to a field is multiexpontential with a major relaxation component of 100 femtoseconds. The observed interfacial hole transfer to Se[sup [minus]2] acceptors is occurring on this same time scale. This observation illustrates charge transfer processes can occur in the strong electronic coupling limit and can be competitive with carrier thermalization.

  18. Studying the star formation process with adaptive optics

    NASA Astrophysics Data System (ADS)

    Menard, Francois; Dougados, Catherine; Duchene, Gaspard; Bouvier, Jerome; Duvert, Gilles; Lavalley, Claudia; Monin, Jean-Louis; Beuzit, Jean-Luc

    2000-07-01

    Young Stellar Objects (YSOs) are the builders of worlds. During its infancy, a star transforms ordinary interstellar dust particles into astronomical gold: planets to say the process is complex, and largely unknown to data. Yet, violent and spectacular events of mass ejection are witnessed, disks in keplerian rotation are detected, multiple stars dancing around each other are found. These are as many traces of the stellar and planet formation process. The high angular resolution provided by adaptive optics, and the related gain in sensitivity, have allowed major breakthrough discoveries to be made in each of these specific fields and our understanding of the various physical processes involved in the formation of a star has leaped forward tremendously over the last few years. In the following, meant as a report of the progress made recently in star formation due to adaptive optics, we will describe new results obtained at optical and near- infrared wavelengths, in imaging and spectroscopic modes. Our images of accretion disks and ionized stellar jets permit direct measurements of many physical parameters and shed light into the physics of the accretion and ejection processes. Although the accretion/ejection process so fundamental to star formation is usually studied around single objects, most of young stars form as part of multiple systems. We also present our findings on how the fraction of stars in binary systems evolves with age. The implications of these results on the conditions under which these stars must have formed are discussed.

  19. Optical Quality and Related Factors in Ocular Hypertension: Preliminary Study

    PubMed Central

    Wang, Yu-jing; Yang, Yan-ning; Huang, Lin-ying; Wang, Bo; Han, Yu-can; Yan, Jiang-bo

    2016-01-01

    Background. To evaluate the optical quality and related factors in patients with ocular hypertension (OHT). Methods. This was a prospective case-control study. A total of 12 eyes with OHT and 20 control eyes underwent testing with Optical Quality Analysis System II (OQAS II) to evaluate the modulation transfer function cut off frequency (MTF cutoff), the Strehl 2D ratio (SR), objective scatter index (OSI), tear-film mean OSI (TFOSI), and the OQAS values (OV100%,OV20%, and OV9%). Results. The optical quality of patients with OHT declined, with lower MTF cutoff (OHT 36.86 ± 7.11 cpd , controls 48.50 ± 4.04 cpd, t = −4.60, P < 0.05), lower SR (OHT 0.22 ± 0.04, controls 0.27 ± 0.05, t = −2.72, P < 0.05), lower OV100% (OHT 1.26 ± 0.25, controls 1.61 ± 0.14, t = −4.03, P < 0.05), lower OV20% (OHT 1.27 ± 0.27, controls 1.72 ± 0.20, t = −4.00, P < 0.05), and lower OV9% (OHT 1.30 ± 0.25, controls 1.69 ± 0.32, t = −2.28, P < 0.05). There were not any statistically significant differences in OSI and TFOSI. The MTF cutoff in patients with OHT was correlated significantly with age (r = −0.59, P < 0.05). Conclusions. Optical quality of patients with OHT is reduced, with lower MTF cutoff, SR, OV100%, OV20%, and OV9%. MTF cutoff is negatively related to age. PMID:27293874

  20. Argand-plane vorticity singularities in complex scalar optical fields: an experimental study using optical speckle.

    PubMed

    Rothschild, Freda; Bishop, Alexis I; Kitchen, Marcus J; Paganin, David M

    2014-03-24

    The Cornu spiral is, in essence, the image resulting from an Argand-plane map associated with monochromatic complex scalar plane waves diffracting from an infinite edge. Argand-plane maps can be useful in the analysis of more general optical fields. We experimentally study particular features of Argand-plane mappings known as "vorticity singularities" that are associated with mapping continuous single-valued complex scalar speckle fields to the Argand plane. Vorticity singularities possess a hierarchy of Argand-plane catastrophes including the fold, cusp and elliptic umbilic. We also confirm their connection to vortices in two-dimensional complex scalar waves. The study of vorticity singularities may also have implications for higher-dimensional fields such as coherence functions and multi-component fields such as vector and spinor fields. PMID:24663998

  1. Some case studies of ocean wave physical processes utilizing the GSFC airborne radar ocean wave spectrometer

    NASA Technical Reports Server (NTRS)

    Jackson, F. C.

    1984-01-01

    The NASA K sub u band Radar Ocean Wave Spectrometer (ROWS) is an experimental prototype of a possible future satellite instrument for low data rate global waves measurements. The ROWS technique, which utilizes short pulse radar altimeters in a conical scan mode near vertical incidence to map the directional slope spectrum in wave number and azimuth, is briefly described. The potential of the technique is illustrated by some specific case studies of wave physical processes utilizing the aircraft ROWS data. These include: (1) an evaluation of numerical hindcast model performance in storm sea conditions, (2) a study of fetch limited wave growth, and (3) a study of the fully developed sea state. Results of these studies, which are briefly summarized, show how directional wave spectral observations from a mobile platform can contribute enormously to our understanding of wave physical processes.

  2. Lewis Research Center studies of multiple large wind turbine generators on a utility network

    NASA Technical Reports Server (NTRS)

    Gilbert, L. J.; Triezenberg, D. M.

    1979-01-01

    A NASA-Lewis program to study the anticipated performance of a wind turbine generator farm on an electric utility network is surveyed. The paper describes the approach of the Lewis Wind Energy Project Office to developing analysis capabilities in the area of wind turbine generator-utility network computer simulations. Attention is given to areas such as, the Lewis Purdue hybrid simulation, an independent stability study, DOE multiunit plant study, and the WEST simulator. Also covered are the Lewis mod-2 simulation including analog simulation of a two wind turbine system and comparison with Boeing simulation results, and gust response of a two machine model. Finally future work to be done is noted and it is concluded that the study shows little interaction between the generators and between the generators and the bus.

  3. Optical Investigations of Physiology: A Study of Intrinsic and Extrinsic Biomedical Contrast

    NASA Astrophysics Data System (ADS)

    Chance, Britton; Luo, Qingming; Nioka, Shoko; Alsop, David C.; Detre, John A.

    1997-06-01

    The utility and performance of optical studies of tissue depends upon the contrast and the changes of contrast in health and disease and in functional activity. The contrast is determined both by the optical properties of extrinsic and intrinsic chromophores and scatterers but especially upon the changes evoked by physiological activity and pathological states. Here, we have focused upon absorption changes of the intrinsic probe, blood absorbance changes due to cortical hypoxia and to haematomas, giving, for particular conditions, absorbance changes of 0.15 and over 0.4 Δ OD, respectively. Functional activity may give changes of blood volume of over 0.05 Δ OD with some variability due to individual responses that is best expressed as histogram displays of the distribution of response among a significant population. Responses have been observed in prefrontal parietal and occipital functions (242 tests). Extrinsic probes afford signals dependent upon the dose tolerance of the subject and can readily equal or exceed the blood volume and oxygenation signals, and currently afford vascular volume and flow indications. However, contrast agents for the functional activity of cellular function are ultimately to be expected. Finally, light-scattering changes afford osmolyte-related responses and are here shown to indicate a large signal attributed to cortical depolarization and K+ release in hypoxia/ischaemia. Thus, the optical method affords imaging of manifold contrasts that greatly enhance its specificity and sensitivity for diagnostic procedures.

  4. Unique Search and Track Procedures Utilizing the Ground-based Electro-Optical Deep Space Surveillance (GEODSS) Worldwide Sites

    NASA Astrophysics Data System (ADS)

    Bruck, R.; Peppard, T.

    2012-09-01

    The GEODSS Vela Search Team, in conjunction with the Air Force, developed revolutionary new procedures to search for man-made objects in deep space. In the first-ever aggressive, proactive campaign against a series of lost satellites, three GEODSS optical detachments were employed to find Vela communication satellites launched in the 1960s. These satellites, in highly eccentric orbits, had not been tracked in over 40 years. The Team exploited GEODSS telescopes and technology for a mission they were not designed to perform by employing modified optical viewing parameters and new search techniques. Using the sun to provide illumination, while modifying optical parameters, the GEODSS team found 5 lost Vela satellites and enhanced the Air Force Space Command satellite catalog. In addition, the Team developed two new tactics, techniques & procedures to capture very hard-to-track objects. Revisit time was increased from intermittent and yearly tracking to weeks or better to find 3 Velas lost for over four decades. The Joint Space Operations Center (JSPOC) analysts stated that the Vela search and tracking was a great success. Additionally, a GEODSS Tactics Development Team was the first to use a deep space observing telescope to track satellites in near earth orbits and outside of the traditional observing period. The team was able to observe and provide metric track data on the International Space Station, Hubble Space Telescope and several other satellites in Near Earth Orbits. Additionally, data was collected before the civil sunset observing period on the Phobos-Grunt re-entry and an Iridium Communications Satellite in Low Earth Orbit. The ability to observe and then successfully repeat the process was an astronomical achievement. The GEODSS team accomplishments pushed the boundaries of the GEODSS system design and proved existing capabilities that had not yet been considered. Lessons learned were established for Vela & other orbit types.

  5. Modulation of retinal image vasculature analysis to extend utility and provide secondary value from optical coherence tomography imaging.

    PubMed

    Cameron, James R; Ballerini, Lucia; Langan, Clare; Warren, Claire; Denholm, Nicholas; Smart, Katie; MacGillivray, Thomas J

    2016-04-01

    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

  6. High Resolution Tsunami Vulnerability Assessment for Coastal Utilities; Case Studies in the Sea of Marmara

    NASA Astrophysics Data System (ADS)

    Yalciner, A. C.; Aytore, B.; Cankaya, C.; Guler, H. G.; Suzen, L.; Zaytsev, A.; Arikawa, T.; Takashi, T.

    2014-12-01

    Resilience of coastal utilities against earthquakes and tsunamis have major importance for efficient and proper rescue and recovery operations soon after disasters. Istanbul as a mega city have long coastline and strongly interact with Marmara sea with its dense coastal utilization. Yenikapi region and Haydarpasa port are two of major coastal utilities. Haydarpasa port has critical components such as the main transportation hub at Asian side of megacity Istanbul, cargo and container stock areas, ro-ro handling operations and passenger terminals. Yenikapi area serves different coastal activities and marine passenger transportation in the Marmara sea. High resolution GIS database of the Istanbul Metropolitan Municipality (IMM) is analyzed and detaled bathymetry and topography database is developed considering vulnerability of the near shore structures and buildings. Two different tsunami numerical models i) NAMIDANCE code (2-Dimensional, depth averaged shallow water model with dispersion hybrid model) and ii) STOC-CADMAS System (Quasi 3-Dimensional in large domains and 3-Dimensional in small domains hybrid model) are used in nested domain in simulations. In this study the accurate vulnerability assessments of these coastal utilities are performed by utilizing high performance computing technology with high resolution bathymetry and topography data for Haydarpasa and Yenikapi regions based on accurate GIS data. The results of computed 2D and 3D numerical models and also the achievements by high performance Computing systems are evaluated. As the result, the computed tsunami parameters inside the coastal utilities are compared and discussed to clarify the benefits of using high resolution data and using the 2D and 3D numerical models.

  7. Public Utility Regulatory Policies Act of 1978: Natural Gas Rate Design Study

    SciTech Connect

    1980-05-01

    First, the comments on May 3, 1979 Notice of Inquiry of DOE relating to the Gas Utility Rate Design Study Required by Section 306 of PURPA are presented. Then, comments on the following are included: (1) ICF Gas Utility Model, Gas Utility Model Data Outputs, Scenario Design; (2) Interim Model Development Report with Example Case Illustrations; (3) Interim Report on Simulation of Seven Rate Forms; (4) Methodology for Assessing the Impacts of Alternative Rate Designs on Industrial Energy Use; (5) Simulation of Marginal-Cost-Based Natural Gas Rates; and (6) Preliminary Discussion Draft of the Gas Rate Design Study. Among the most frequent comments expressed were the following: (a) the public should be given the opportunity to review the final report prior to its submission to Congress; (b) results based on a single computer model of only four hypothetical utility situations cannot be used for policy-making purposes for individual companies or the entire gas industry; (c) there has been an unobjective treatment of traditional and economic cost rate structures; the practical difficulties and potential detrimental consequences of economic cost rates are not fully disclosed; and (d) it is erroneous to assume that end users, particularly residential customers, are influenced by price signals in the rate structure, as opposed to the total bill.

  8. How to Undertake Research of MHC Utilization in Under-developed Countries? A Case Study of MHC Utilization in Central and Western Rural China

    PubMed Central

    Wang, Zhaoxin; Zhang, Yin; Chen, Minxing

    2014-01-01

    Objective: This study was undertaken to address practical problems in maternal health care (MHC) utilization and conduct in-depth study of maternal health services utilization in underdeveloped countries(regions), thus to contribute to the achieving of the UN Millennium Development Goal 5. Data Collection: After searching and screening based on key words like “MHC” and “utilization”, we included 45 English articles and 106 Chinese articles from Pubmed, Medline, China Knowledge Resource Integrated and Wang Fang data base. The research themes, issues, designs, perspectives, dimensions and methods of these dissertations were analyzed. Results: The development of MHC utilization research can be divided into three phases: Studies of the first phase focused primarily on decreasing MMR, which caused attention to the central and western rural areas maternal health services in China from domestic as well as international community; Studies of the second phase centered around the practical impacts of the implementation of MHC relevant programs and policy, confirming that the implementation of these programs and policies improved MHC service delivery and utilization, and promoted cooperation between researchers and practitioners; Studies of the third phase focused on the quality of MHC service utilization. We also found that the major problem in the current MHC service utilization is the huge gap across regions and the existing researches lack innovation and comparison researches between in different countries. Conclusion: Research themes of MHC services change regularly. We should grasp the characteristics and defects of current research to increase the innovation of future research and to better response to the problem solving, and thus to provide more valuable reference for the policy and practice of underdeveloped countries and areas. PMID:24639861

  9. Comparative study of paediatric prescription drug utilization between the spanish and immigrant population

    PubMed Central

    2009-01-01

    Background The immigrant population has increased greatly in Spain in recent years to the point where immigrants made up 12% of the infant population in 2008. There is little information available on the profile of this group with regard to prescription drug utilization in universal public health care systems such as that operating in Spain. This work studies the overall and specific differences in prescription drug utilization between the immigrant and Spanish population. Methods Use was made of the Aragonese Health Service databases for 2006. The studied population comprises 159,908 children aged 0-14 years, 13.6% of whom are foreign nationals. Different utilization variables were calculated for each group. Prescription-drug consumption is measured in Defined Daily Doses (DDD) and DDD/1000 persons/day/(DID). Results A total of 833,223 prescriptions were studied. Utilization is lower for immigrant children than in Spanish children for both DID (66.27 v. 113.67) and average annual expense (€21.55 v. €41.14). Immigrant children consume fewer prescription drugs than Spanish children in all of the therapy groups, with the most prescribed (in DID) being: respiratory system, anti-infectives for systemic use, nervous system, sensory organs. Significant differences were observed in relation to the type of drugs and the geographical background of immigrants. Conclusion Prescription drug utilization is much greater in Spanish children than in immigrant children, particularly with reference to bronchodilators (montelukast and terbutaline) and attention-disorder hyperactivity drugs such as methylphenidate. There are important differences regarding drug type and depending on immigrants' geographical backgrounds that suggest there are social, cultural and access factors underlying these disparities. PMID:19995453

  10. Comparison of formats for the development of fiber-optic biosensors utilizing sol-gel derived materials entrapping fluorescently-labelled protein.

    PubMed

    Flora, K; Brennan, J D

    1999-10-01

    The development of fiber-optic biosensors requires that a biorecognition element and a fluorescent reporter group be immobilized at or near the surface of an optical element such as a planar waveguide or optical fiber. In this study, we examined a model biorecognition element-reporter group couple consisting of human serum albumin that was site-selectively labelled at Cys 34 with iodoacetoxy-nitrobenzoxadiazole (HSA-NBD). The labelled protein was encapsulated into sol-gel derived materials that were prepared either as monoliths, as beads that were formed at the distal tip of a fused silica optical fiber, or as thin films that were dipcast along the length of a glass slide or optical fiber. For fiber-based studies, the entrapped protein was excited using a helium-cadmium laser that was launched into a single optical fiber, and emission was separated from the incident radiation using a perforated mirror beam-splitter, and detected using a monochromator-photomultiplier tube assembly. Changes in fluorescence intensity were generated by denaturant-induced conformational changes in the protein or by iodide quenching. The analytical parameters of merit for the different encapsulation formats, including minimum protein loading level, response time and limit-of-detection, were examined, as were factors such as protein accessibility, leaching and photobleaching. Overall, the results indicated that both beads and films were suitable for biosensor development. In both formats, a substantial fraction of the entrapped protein remained accessible, and the entrapped protein retained a large degree of conformational flexibility. Thin films showed the most rapid response times, and provided good detection limits for a model analyte. However, the entrapment of proteins into beads at the distal tip of fibers provided better signal-to-noise and signal-to-background ratios, and required less protein for preparation. Hence, beads appear to be the most viable method for interfacing of

  11. 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

    2016-09-01

    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. PMID:27607637

  12. 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.

  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. PMID:25608081

  14. Utility of genome-wide association study findings: prostate cancer as a translational research paradigm.

    PubMed

    Turner, A R; Kader, A K; Xu, J

    2012-04-01

    Genome-wide association studies have identified thousands of consistently replicated associations between genetic markers and complex disease risk, including cancers. Alone, these markers have limited utility in risk prediction; however, when several of these markers are used in combination, the predictive performance appears to be similar to that of many currently available clinical predictors. Despite this, there are divergent views regarding the clinical validity and utility of these genetic markers in risk prediction. There are valid concerns, thus providing a direction for new lines of research. Herein, we outline the debate and use the example of prostate cancer to highlight emerging evidence from studies that aim to address potential concerns. We also describe a translational framework that could be used to guide the development of a new generation of comprehensive research studies aimed at capitalizing on these exciting new discoveries. PMID:22272820

  15. Optical studies of dynamical processes in disordered systems. Progress report

    SciTech Connect

    Yen, W.M.

    1994-05-01

    The authors present an abbreviated summary of the progress they have attained in the course of the abbreviated first year of the present three-year grant. The focus of their research continues to be on studies which help them understand various dynamical processes which affect the structure and the optical properties of disordered and amorphous materials. They continue to make significant progress in their attempts to understand the factors which affect, for example, the efficiencies of activated glasses. This report contains a brief description of the work they have carried out during the present grant period and an outline of the initiatives they are presently undertaking or continuing during the second period.

  16. Optical, dielectric and microhardness studies on (100) directed ADP crystal.

    PubMed

    Rajesh, P; Ramasamy, P

    2009-09-15

    (100) directed ammonium dihydrogen phosphate single crystal has been grown using the uniaxially solution-crystallization method of Sankaranarayanan-Ramasamy (SR). The size of the grown crystal is 40 mm in diameter and 50mm in thickness. The grown crystals were characterized by UV-vis spectroscopy, Vickers hardness and dielectric studies. Comparing the (100) plane of the conventional method grown ADP crystal with (100) directed SR method grown ADP crystal, optical transparency, dielectric constant and Vickers hardness number are increased and dielectric loss is decreased in SR method grown crystal. PMID:19592298

  17. Optical traps to study properties of molecular motors.

    PubMed

    Spudich, James A; Rice, Sarah E; Rock, Ronald S; Purcell, Thomas J; Warrick, Hans M

    2011-11-01

    In vitro motility assays enabled the analysis of coupling between ATP hydrolysis and movement of myosin along actin filaments or kinesin along microtubules. Single-molecule assays using laser trapping have been used to obtain more detailed information about kinesins, myosins, and processive DNA enzymes. The combination of in vitro motility assays with laser-trap measurements has revealed detailed dynamic structural changes associated with the ATPase cycle. This article describes the use of optical traps to study processive and nonprocessive molecular motor proteins, focusing on the design of the instrument and the assays to characterize motility. PMID:22046048

  18. Optical Traps to Study Properties of Molecular Motors

    PubMed Central

    Spudich, James A.; Rice, Sarah E.; Rock, Ronald S.; Purcell, Thomas J.; Warrick, Hans M.

    2016-01-01

    In vitro motility assays enabled the analysis of coupling between ATP hydrolysis and movement of myosin along actin filaments or kinesin along microtubules. Single-molecule assays using laser trapping have been used to obtain more detailed information about kinesins, myosins, and processive DNA enzymes. The combination of in vitro motility assays with laser-trap measurements has revealed detailed dynamic structural changes associated with the ATPase cycle. This article describes the use of optical traps to study processive and nonprocessive molecular motor proteins, focusing on the design of the instrument and the assays to characterize motility. PMID:22046048

  19. Theoretical study of nonlinear optical properties of oxocarbon derivatives

    NASA Astrophysics Data System (ADS)

    Junqueira, G. M. A.; Faria, M. S.; da Silva, A. M.; Dos Santos, H. F.

    In this work, first hyperpolarizability (β) and electronic spectra were obtained at ab initio and semiempirical levels of theory for mono- and bi-squarate derivatives. The results from our calculations suggest the investigated compounds as potential molecules for nonlinear optics (NLO). By means of the employed theoretical methodology, it was possible to identify structural aspects leading to enhancement of the NLO properties of the studied oxocarbons. Furthermore, a correlation between Hammett parameters of the substituents (∑σp) and ln (βtot) was established.

  20. Optical studies of dynamical processes in disordered systems

    NASA Astrophysics Data System (ADS)

    Yen, W. M.

    We present a brief summary of the progress we have attained in the course of the second year of the present three year rant. The focus of our research continues to be on studies of those dynamical processes such as relaxation and energy diffusion which affect the structure and the optical properties of disordered and amorphous materials. We have been particularly concerned with some new glass compositions which are luminescent in the near infrared (NIR) and on the factors which determine the efficiencies of these materials. In addition, we have begun to investigate the nature and the dynamics of the elementary excitations characteristic of amorphous materials.

  1. Study of effective optical thickness in photopolymer for application.

    PubMed

    Wang, Heng; Wang, Jian; Liu, Hongpeng; Yu, Dan; Sun, Xiudong; Zhang, Jingwen

    2012-06-15

    The impact of the effective optical thickness of a photopolymer on its holographic performance was studied. To overcome the attenuation of gratings for a better uniformity, a multilayer approach was introduced, by adjusting concentrations of dye along the depth of photopolymer to compensate the attenuation of recording light due to absorption. Multilayer photopolymers with thicknesses over 500 μm were designed, fabricated, and characterized experimentally, exhibiting better Bragg selectivity. More holograms were stored in multilayer material by angular multiplexing, and the cumulative grating strength was enhanced, leading towards larger holographic storage capacity. PMID:22739868

  2. Optical and photometric studies of Earth orbiting small space objects

    NASA Astrophysics Data System (ADS)

    Selim, I. M.; El-Hameed, Afaf M. Abd; Bakhtigaraev, N. S.; Attia, Gamal F.

    2016-03-01

    Variations of light curves for space objects are investigated. Optical observations and photometric measurements for small space debris on highly elliptical orbits (HEO) and geostationary orbits (GEO) are used to determine their orbital parameters. Light curves of small space debris with various area-to-mass ratios and orbital characteristics are discussed. Tracking of some objects shows very rapid brightness variations related to perturbations of the orbital parameters. Changes in brightness and equatorial coordinates of the studied objects are found in observational data. Our results allow improving the accuracy of space debris orbital elements.

  3. Area-Specific Marginal Costing for Electric Utilities: a Case Study of Transmission and Distribution Costs

    NASA Astrophysics Data System (ADS)

    Orans, Ren

    1990-10-01

    utility distribution investment. The study makes use of data from an actual distribution planning area, located within PGandE's service territory, to demonstrate the important characteristics of this new costing approach. The most significant result of this empirical work is that geographic differences in the cost of capacity in distribution systems can be as much as four times larger than the current system average utility estimates. Furthermore, lumpy capital investment patterns can lead to significant cost differences over time.

  4. Optical Studies on Antimonide Superlattice Infrared Detector Material

    NASA Technical Reports Server (NTRS)

    Hoglund, Linda; Soibel, Alexander; Hill, Cory J.; Ting, David Z.; Khoshakhlagh, Arezou; Liao, Anna; Keo, Sam; Lee, Michael C.; Nguyen, Jean; Mumolo, Jason M.; Gunapala, Sarath D.

    2010-01-01

    In this study the material quality and optical properties of type II InAs/GaSb superlattices are investigated using transmission and photoluminescence (PL) spectroscopy. The influence of the material quality on the intensity of the luminescence and on the electrical properties of the detectors is studied and a good correlation between the photodetector current-voltage (IV) characteristics and the PL intensity is observed. Studies of the temperature dependence of the PL reveal that Shockley-Read-Hall processes are limiting the minority carrier lifetime in both the mid-IR wavelength and the long-IR wavelength detector material studied. These results demonstrate that PL spectroscopy is a valuable tool for optimization of infrared detectors.

  5. Performance study of IP and SONET grooming in optical WDM mesh networks

    NASA Astrophysics Data System (ADS)

    Shenai, Ramakrishna; Sivalingam, Krishna

    2007-06-01

    We study the problem of IP traffic grooming in optical wavelength-division-multiplexed (WDM) mesh networks. Two different grooming architectures are considered: (i) IP/MPLS grooming, and (ii) SONET grooming. The IP/MPLS grooming approach provides a fine level of grooming granularity realized via software-based implementations but has router-processing-related bottlenecks. The SONET grooming approach is realized in dedicated hardware, but it is more expensive and typically offers limited grooming granularity choices. We also consider multipath routing as used in SONET virtual concatenation techniques, and we study the impact of the differential delay constraint. A detailed comparison of the different grooming options in terms of blocking probability, lightpath utilization, and survivability issues is presented. The simulation analysis helps quantify the improved performance of finer granularity grooming approaches over the coarser SONET-based approaches.

  6. Design studies of quasi-optical gyro amplifiers

    SciTech Connect

    Hu, W.; Kreischer, K.E.; Temkin, R.J.

    1995-12-31

    The Quasi-Optical Gyro Amplifier is a novel device for generating high-frequency, high-power coherent microwave radiation. The authors report a study on a quasi-optical gyro amplifier designed with a periodic mirror structure. A specific design is presented for an amplifier at 95 GHz with an output power level of 100 kW and an efficiency of 30%. The system consists of two sets of parallel mirrors facing each other. A free space Gaussian beam can propagate through the structure in a zigzagged path. An on axis gyrotron beam interacts with the radiation each time it crosses the Gaussian waist. With a beam of 70 kV, 5A and velocity ratio of 1.5, this nonlinear simulation shows that this device can be 16% efficient. With a tapered magnetic field, the efficiency can be increased to 40%. However, studies also show that electron velocity spread significantly reduces the gain. More seriously, bunched electrons considerably change the direction of radiation propagation. These issues need to be addressed in further studies.

  7. Imaging studies for diagnosing Graves' orbitopathy and dysthyroid optic neuropathy

    PubMed Central

    Gonçalves, Allan C. Pieroni; Gebrim, Eloísa M. M. S.; Monteiro, Mário L. R.

    2012-01-01

    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. PMID:23184212

  8. Night Myopia Studied with an Adaptive Optics Visual Analyzer

    PubMed Central

    Artal, Pablo; Schwarz, Christina; Cánovas, Carmen; Mira-Agudelo, Alejandro

    2012-01-01

    Purpose Eyes with distant objects in focus in daylight are thought to become myopic in dim light. This phenomenon, often called “night myopia” has been studied extensively for several decades. However, despite its general acceptance, its magnitude and causes are still controversial. A series of experiments were performed to understand night myopia in greater detail. Methods We used an adaptive optics instrument operating in invisible infrared light to elucidate the actual magnitude of night myopia and its main causes. The experimental setup allowed the manipulation of the eye's aberrations (and particularly spherical aberration) as well as the use of monochromatic and polychromatic stimuli. Eight subjects with normal vision monocularly determined their best focus position subjectively for a Maltese cross stimulus at different levels of luminance, from the baseline condition of 20 cd/m2 to the lowest luminance of 22×10−6 cd/m2. While subjects performed the focusing tasks, their eye's defocus and aberrations were continuously measured with the 1050-nm Hartmann-Shack sensor incorporated in the adaptive optics instrument. The experiment was repeated for a variety of controlled conditions incorporating specific aberrations of the eye and chromatic content of the stimuli. Results We found large inter-subject variability and an average of −0.8 D myopic shift for low light conditions. The main cause responsible for night myopia was the accommodation shift occurring at low light levels. Other factors, traditionally suggested to explain night myopia, such as chromatic and spherical aberrations, have a much smaller effect in this mechanism. Conclusions An adaptive optics visual analyzer was applied to study the phenomenon of night myopia. We found that the defocus shift occurring in dim light is mainly due to accommodation errors. PMID:22768343

  9. Healthcare utilization and costs in patients beginning pharmacotherapy for generalized anxiety disorder: a retrospective cohort study

    PubMed Central

    2011-01-01

    Background Patterns of healthcare utilization and costs in patients beginning pharmacotherapy for generalized anxiety disorder (GAD) have not been well characterized. Methods Using a large US health insurance database, we identified all patients with evidence of GAD (ICD-9-CM diagnosis code 300.02) who initiated pharmacotherapy with medications commonly used to treat GAD (eg, selective serotonin reuptake inhibitors [SSRIs], venlafaxine, benzodiazepines) between 1/1/2003 and 12/31/2007. We examined healthcare utilization and costs over the 12-month periods preceding and following date of initial receipt of such therapy ("pretreatment" and "follow-up", respectively). Patients with incomplete data were excluded. Results A total of 10,275 patients met all study inclusion criteria. Forty-eight percent of patients received SSRIs; 34%, benzodiazepines; and 6%, venlafaxine. SSRIs and venlafaxine were about three times more likely to be used on a long-term basis (> 90 days) than benzodiazepines (p < 0.01). In general, levels of healthcare utilization were higher during follow-up than pretreatment. Mean (SD) total healthcare costs increased from $4812 ($10,006) during pretreatment to $7182 ($22,041) during follow-up (p < 0.01); costs of GAD-related pharmacotherapy during follow-up were $420 ($485). Conclusions More than one-half of patients initiating pharmacotherapy for GAD receive either SSRIs or venlafaxine. Levels of healthcare utilization and costs are greater in the year following initiation of therapy than in the immediately preceding one. PMID:22151689

  10. The study of optical fiber communication technology for space optical remote sensing

    NASA Astrophysics Data System (ADS)

    Zheng, Jun; Yu, Sheng-quan; Zhang, Xiao-hong; Zhang, Rong-hui; Ma, Jian-hua

    2012-11-01

    The latest trends of Space Optical Remote Sensing are high-resolution, multispectral, and wide swath detecting. High-speed digital image data transmission will be more important for remote sensing. At present, the data output interface of Space Optical Remote Sensing, after performing the image data compression and formatting, transfers the image data to data storage unit of the Spacecraft through LVDS circuit cables. But this method is not recommended for high-speed digital image data transmission. This type of image data transmission, called source synchronization, has the low performance for high-speed digital signal. Besides, it is difficult for cable installing and system testing in limited space of vehicle. To resolve these issues as above, this paper describes a high-speed interconnection device for Space Optical Remote Sensing with Spacecraft. To meet its objectives, this device is comprised of Virtex-5 FPGA with embedded high-speed series and power-efficient transceiver, fiber-optic transceiver module, the unit of fiber-optic connection and single mode optical fiber. The special communication protocol is performed for image data transferring system. The unit of fiber-optic connection with high reliability and flexibility is provided for transferring high-speed serial data with optical fiber. It is evident that this method provides many advantages for Space Optical Remote Sensing: 1. Improving the speed of image data transferring of Space Optical Remote Sensing; 2. Enhancing the reliability and safety of image data transferring; 3. Space Optical Remote Sensing will be reduced significantly in size and in weight; 4. System installing and system testing for Space Optical Remote Sensing will become easier.

  11. Optically tunable microwave, millimeter-wave and submillimeter-wave utilizing single-mode Fabry-Pérot laser diode subject to optical feedback.

    PubMed

    Wu, Jian-Wei; Nakarmi, Bikash; Won, Yong Hyub

    2016-02-01

    In this paper, we use optical feedback injection technique to generate tunable microwave, millimeter-wave and submillimeter-wave signals using single-mode Fabry-Pérot laser diode. The beat frequency of the proposed generator ranges from 30.4 GHz to 3.40 THz. The peak power ratio between two resonating modes at the output spectrum of can be less than 0.5 dB by judiciously selecting feedback wavelength. In the stabilization test, the peak fluctuation of photonic signal is as low as 0.19 dB within half hour. Aside from locking regions, where the laser is easily locked by the injection beam, the side-mode suppression ratio is well over 25 dB with the maximum value of 36.6 dB at 30.4 GHz beat frequency. In addition, the minimum beat frequency interval between two adjacent photonic signals is as low as 10 GHz. PMID:26906837

  12. Athermal distributed Brillouin sensors utilizing all-glass optical fibers fabricated from rare earth garnets: LuAG

    NASA Astrophysics Data System (ADS)

    Dragic, P. D.; Pamato, M. G.; Iordache, V.; Bass, J. D.; Kucera, C. J.; Jones, M.; Hawkins, T. W.; Ballato, J.

    2016-01-01

    An all-glass optical fiber derived from single-crystal LuAG is investigated for its potential use in athermal Brillouin distributed strain sensors. Such sensor systems are comprised of fiber whose Brillouin frequency shift is independent of temperature, but not independent of strain. Bulk Brillouin spectroscopy measurements on the precursor LuAG crystal are performed to gain insight into the crystal-to-glass transition. Results suggest that both the mass density and acoustic velocity are reduced relative to the crystal phase, in common with the other rare earth aluminosilicates. Advantages of the LuAG derived fiber over other rare earth garnet-derived fibers for the sensing application are a stronger strain response and larger Brilloun gain with narrower Brillouin spectral width.

  13. A food waste utilization study for removing lead(II) from drinks.

    PubMed

    Kaplan Ince, Olcay; Ince, Muharrem; Yonten, Vahap; Goksu, Ali

    2017-01-01

    This is the first study about removal of lead (Pb(II)) from energy drinks. In this paper, food waste, namely eggshell (hydroxyapatite) utilization, was used to remove Pb(II) from mineral water and energy drinks. Mineral water and energy drinks were chosen for removal of lead since the latter is severely hazardous to human health even in small amounts. Response Surface Methodology (RSM) was performed to optimize the application process by practice of the quadratic model united with the Central Composite Design (CCD) and quadratic combined program was utilized to study the most effective parameters on aforementioned liquids. Through the application of variance analysis (ANOVA) factors critical to removing of lead were identified for each experimental design response. Maximum adsorption capacity of eggshell was achieved as 923mgg(-1) for Pb(II). The obtained optimum conditions were applied to drinks. Results showed that used adsorbent was quite effective in removing Pb(II) from drinks. PMID:27507520

  14. Dislocations, microhardness and optical studies on glycine potassium nitrate crystal

    NASA Astrophysics Data System (ADS)

    Chandra, Ch. Sateesh; Nagaraju, D.; Shekar, P. V. Raja; Rao, T. Tirumal; Krishna, N. Gopi

    2015-06-01

    Single crystals of glycine potassium nitrate (GPN), a semiorganic nonlinear optical crystal, of dimensions 15×12×4 mm3 were grown in a period of 10 days. The defect content present in the crystals was estimated by chemical etching technique. The results indicate that the average dislocation density is about 4.1×103/cm2. The UV-Vis. studies indicate that the crystal has a wide transmission range. The Kurtz powder test indicates that the second harmonic generation efficiency of GPN is 2.5 times that of KDP. The load-hardness curves for GPN were studied over the load range 10-100 g. The anisotropy in hardness was studied using Knoop indentation technique.

  15. Optical Near Field Studies of Plasmonic and Optical Antennas For Sensitive and Selective Biosensing Applications

    NASA Astrophysics Data System (ADS)

    Gelfand, Ryan M.

    For biosensing applications a useful device needs at least two properties: high sensitivity and high selectivity. Optical spectroscopy offers unique advantages over other sensing techniques however one big challenge to overcome is the mismatch between wavelength and the size of biologically relevant molecules. In order to have high enough sensitivity to approach the single-molecule limit, the interaction between the light and the molecule should be strong. However, the diffraction limit of light is approximately half the incidence wavelength, on the order of 100 nm for the smallest nondestructive wavelengths. This presents a significant mismatch between the size of the molecule and the smallest focus spot of the light. The photo-excitation should be compressed more than 100 fold to interact strongly. We must use metallic antennas that convert the incidence radiation into plasmonic modes which can then be compressed well below the wavelength diffraction limit. Studying the near field characteristics of these metallic nanostructures will help us gain insight into this emerging field and allow us to better use them in developing next generation devices. We have developed different geometries of these antennas and simulated their performance using Finite Difference Time Domain software. We have concentrated our efforts in the mid-infrared because that is the natural molecular vibration frequency region and also the near infrared because at these frequencies there exists a mature industry for compact sources, detectors, and fiber optic components. Our simulations show a 6,000 fold mode compression for a bowtie antenna and a million fold compression for a plasmonic photonic crystal (ppc) antenna. The bull's-eye antenna does not have as a high a mode compression but it has a natural geometry for molecular sensing due to the central metallic disc. Experimentally, we have measured the near field of these antennas with a custom back reflection apertureless NSOM setup in both

  16. Picosecond electron-optic diagnostics in laser studies

    NASA Astrophysics Data System (ADS)

    Prokhorov, A. M.

    The papers included in this volume provide an overview of research aimed at the development of methods and instrumentation for ultrahigh-speed electron-optic detection and of their applications in laser physics, laser fusion, fiber-optic communication, picosecond spectroscopy, and photobiology. Topics discussed include the physics of a picosecond electron-optic converter, the aberration theory for cathode lenses, picosecond and subpicosecond laser sources, and a beam deflection system for a subpicosecond electron-optic converter.

  17. Study of fiber optics standardization, reliability, and applications

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The use of fiber optics in space applications is investigated. Manufacturers and users detailed the problems they were having with the use or manufacture of fiber optic components. The general consensus of all the companies/agencies interviewed is that fiber optics is a maturing technology and will definitely have a place in future NASA system designs. The use of fiber optics was found to have two main advantages - weight savings and increased bandwidth.

  18. Optic Disc - Fovea Angle: The Beijing Eye Study 2011

    PubMed Central

    Jonas, Rahul A.; Wang, Ya Xing; Yang, Hua; Li, Jian Jun; Xu, Liang; Panda-Jonas, Songhomitra; Jonas, Jost B.

    2015-01-01

    Purpose To determine the optic disc-fovea angle (defined as angle between the horizontal and the line between the optic disc center and the fovea) and to assess its relationships with ocular and systemic parameters. Methods The population-based cross-sectional Beijing Eye Study 2011 included 3468 individuals. A detailed ophthalmic examination was carried out. Using fundus photographs, we measured the disc-fovea angle. Results Readable fundus photographs were available for 6043 eyes of 3052 (88.0%) individuals with a mean age of 63.6±9.3 years (range: 50–91 years) and a mean axial length of 23.2±1.0 mm (range: 18.96–28.87 mm). Mean disc-fovea angle was 7.76 ± 3.63° (median: 7.65°; range: -6.3° to 28.9°). The mean inter-eye difference was 4.01 ± 2.94° (median: 3.49°; range: 0.00–22.3°). In multivariate analysis, larger disc-fovea angle was associated (regression coefficient r2: 0.08) with older age (P = 0.009; standardized regression coefficient beta: 0.05), thinner RNFL in the nasal superior sector (P<0.001; beta: -0.17), superior sector (P<0.001; beta: -0.10) and temporal superior sector (P<0.001; beta: -0.11) and thicker RNFL in the inferior sector (P<001; beta: 0.13), nasal inferior sector (P<001; beta: 0.13) and nasal sector (P = 0.007; beta: 0.06), higher prevalence of retinal vein occlusion (P = 0.02; beta: 0.04), and with larger cylindrical refractive error (P = 0.04; beta: 0.04). Conclusions The optic disc-fovea angle markedly influences the regional distribution of the RNFL thickness pattern. The disc-fovea angle may routinely be taken into account in the morphological glaucoma diagnosis and in the assessment of structure-function relationship in optic nerve diseases. Future studies may address potential associations between a larger disc-fovea angle and retinal vein occlusions and between the disc-fovea angle and the neuroretinal rim shape. PMID:26545259

  19. Ab initio study of optical excitations in VO2

    NASA Astrophysics Data System (ADS)

    Coulter, John; Gali, Adam; Manousakis, Efstratios

    2014-03-01

    Motivated by recent experimental efforts to fabricate p-n junctions from transition metal oxides (TMOs) and a recent theoretical study claiming TMOs to be good absorbers and promising materials for efficient carrier multiplication, we study the optical properties of a prototypical TMO, the insulator M1 phase of vanadium dioxide (VO2), by ab initio methods. We applied the Bethe-Salpeter equations (BSE) to calculate the optical properties, starting from self-consistent GW quasi-particle energy levels and states. In contrast to expectations, the exciton binding energy obtained by BSE is in good agreement with the experiment. We find that the electron-electron interaction is very strong which makes this material promising for efficient carrier multiplication that might lead to an enhanced efficiency in photo-voltaics applications. To illustrate this more quantitatively, we calculated the impact ionization rate within the independent quasiparticle approximation, and find that the rate is significantly higher than silicon in the region of highest solar intensity, due to the strong multiple carrier excitations.

  20. Study on optical weak absorption of borate crystals

    NASA Astrophysics Data System (ADS)

    Li, Xiaomao; Hu, Zhanggui; Yue, Yinchao; Yu, Xuesong; Lin, Zheshuai; Zhang, Guochun

    2013-10-01

    Borate crystal is an important type of nonlinear optical crystals used in frequency conversion in all-solid-state lasers. Especially, LiB3O5 (LBO), CsB3O5 (CBO) and CsLiB6O10 (CLBO) are the most advanced. Although these borate crystals are all constructed by the same anionic group-(B3O7)5-, they show different nonlinear optical properties. In this study, bulk weak absorption values of three borate crystals have been studied at 1064 nm by a photothermal common-path interferometer. The bulk weak absorption values of them along [1 0 0], [0 1 0] and [0 0 1] directions were obtained, respectively, to be approximately 17.5 ppm cm-1, 15 ppm cm-1 and 20 ppm cm-1 (LBO); 80 ppm cm-1, 100 ppm cm-1 and 40 ppm cm-1 (CBO); 600 ppm cm-1, 600 ppm cm-1 and 150 ppm cm-1 (CLBO) at 1064 nm. The results showed an obvious discrepancy of the values of these crystals along three axis directions. A correlation between the bulk weak absorption property and crystal intrinsic structure was then discussed. It is found that the bulk weak absorption values strongly depend on the interstitial area surrounded by the B-O frames. The interstitial area is larger, the bulk weak absorption value is higher.

  1. A review of health utilities using the EQ-5D in studies of cardiovascular disease

    PubMed Central

    2010-01-01

    Background The EQ-5D has been extensively used to assess patient utility in trials of new treatments within the cardiovascular field. The aims of this study were to review evidence of the validity and reliability of the EQ-5D, and to summarise utility scores based on the use of the EQ-5D in clinical trials and in studies of patients with cardiovascular disease. Methods A structured literature search was conducted using keywords related to cardiovascular disease and EQ-5D. Original research studies of patients with cardiovascular disease that reported EQ-5D results and its measurement properties were included. Results Of 147 identified papers, 66 met the selection criteria, with 10 studies reporting evidence on validity or reliability and 60 reporting EQ-5D responses (VAS or self-classification). Mean EQ-5D index-based scores ranged from 0.24 (SD 0.39) to 0.90 (SD 0.16), while VAS scores ranged from 37 (SD 21) to 89 (no SD reported). Stratification of EQ-5D index scores by disease severity revealed that scores decreased from a mean of 0.78 (SD 0.18) to 0.51 (SD 0.21) for mild to severe disease in heart failure patients and from 0.80 (SD 0.05) to 0.45 (SD 0.22) for mild to severe disease in angina patients. Conclusions The published evidence generally supports the validity and reliability of the EQ-5D as an outcome measure within the cardiovascular area. This review provides utility estimates across a range of cardiovascular subgroups and treatments that may be useful for future modelling of utilities and QALYs in economic evaluations within the cardiovascular area. PMID:20109189

  2. A Study About Improvement of Efficiency of a Sewage Heat Utilization System

    NASA Astrophysics Data System (ADS)

    Kobayakawa, Tomoaki; Hihara, Eiji; Hanazaki, Hirotaka

    On the basis of the data analysis of operational performance at the DHC plant in Makuhari HB area, it is examined how the properties of the sewage used as a heat source affect the effectiveness of the system. The result of this study suggests that a sewage heat utilization system is able to perform higher efficiency when it is designed as a distributed system that has separate heat sources than a central system.

  3. Veterans Affairs databases are accurate for gout-related health care utilization: a validation study

    PubMed Central

    2013-01-01

    Introduction The aim of this study was to assess the accuracy of Veterans Affairs (VA) databases for gout-related health care utilization. Methods This retrospective study utilized VA administrative and clinical databases. A random sample of gout patients with visits (outpatient, inpatient or emergent/urgent care) with or without the diagnosis of gout (International Classification of Diseases, ninth revision, common modification ICD-9-CM code of 274.x or 274.xx) at the Birmingham VA hospital was selected. A blinded abstractor performed a review of VA electronic health records for the documentation of gout or gout-related terms (gouty arthritis, tophaceous gout, tophus/tophi, acute gout, chronic gout, podagra, urate stones, urate or uric acid crystals and so on) in the chief complaint, history of present illness or assessment and plan for the visit; this constituted the gold standard for gout-related utilization. The accuracy of database-derived gout-related claims was assessed by calculating sensitivity, specificity, and positive and negative predictive values (PPV and NPV). Results Of 108 potential visits, 85 outpatient, inpatient or urgent care/emergency room visits to a health care provider (85 patients: 84 men and 1 woman with a mean age of 63 years) and retrievable data from medical records constituted the analyzed dataset. Administrative claims for gout-related utilization with ICD-9 code for gout were accurate with a PPV of 86%, specificity of 95%, sensitivity of 86% and NPV of 95%. Conclusions VA databases are accurate for gout-related visits. These findings support their use for studies of health services and outcome studies. It remains to be seen if these findings are generalizable to other settings and databases. PMID:24377421

  4. Linear and nonlinear optical, mechanical, electrical and surface studies of a novel nonlinear optical crystal - Manganese mercury thiocyanate (MMTC)

    NASA Astrophysics Data System (ADS)

    Josephine Usha, R.; Sagayaraj, P.; Joseph, V.

    2014-12-01

    The highly efficient nonlinear optical single crystal of manganese mercury thiocyanate has been grown from slow evaporation solvent technique. The second harmonic generation and optical transmittance of the grown crystal are studied by Kurtz and Perry powder technique and spectroscopic absorbance spectrum. Mechanical behaviour is analyzed using Vickers microhardness test. The dielectric response of the grown crystal is studied as a function of the temperature and the results are discussed. Further, electronic properties such as plasma energy, Penngap, Fermi energy and electronic polarizability are evaluated. Third order nonlinear optical studies are performed using by single beam Z-scan technique using Nd:YAG laser and parameters such as nonlinear refractive index n2, absorption co-efficient β and nonlinear optical susceptibility χ(3) are evaluated for the grown crystal. The surface of the grown crystal is analyzed with field emission scanning electron microscope and atomic force microscope analyses.

  5. Linear and nonlinear optical, mechanical, electrical and surface studies of a novel nonlinear optical crystal - manganese mercury thiocyanate (MMTC).

    PubMed

    Josephine Usha, R; Sagayaraj, P; Joseph, V

    2014-12-10

    The highly efficient nonlinear optical single crystal of manganese mercury thiocyanate has been grown from slow evaporation solvent technique. The second harmonic generation and optical transmittance of the grown crystal are studied by Kurtz and Perry powder technique and spectroscopic absorbance spectrum. Mechanical behaviour is analyzed using Vickers microhardness test. The dielectric response of the grown crystal is studied as a function of the temperature and the results are discussed. Further, electronic properties such as plasma energy, Penngap, Fermi energy and electronic polarizability are evaluated. Third order nonlinear optical studies are performed using by single beam Z-scan technique using Nd:YAG laser and parameters such as nonlinear refractive index n2, absorption co-efficient β and nonlinear optical susceptibility χ((3)) are evaluated for the grown crystal. The surface of the grown crystal is analyzed with field emission scanning electron microscope and atomic force microscope analyses. PMID:24945865

  6. Nipple-areolar Complex Reconstruction following Postmastectomy Breast Reconstruction: A Comparative Utility Assessment Study

    PubMed Central

    Ibrahim, Ahmed M. S.; Sinno, Hani H.; Izadpanah, Ali; Vorstenbosch, Joshua; Dionisopoulos, Tassos; Mureau, Marc A. M.; Tobias, Adam M.; Lee, Bernard T.

    2015-01-01

    Background: Nipple-areola complex (NAC) reconstruction occurs toward the final stage of breast reconstruction; however, not all women follow through with these procedures. The goal of this study was to determine the impact of the health state burden of living with a reconstructed breast before NAC reconstruction. Methods: A sample of the population and medical students at McGill University were recruited to establish the utility scores [visual analog scale (VAS), time trade-off (TTO), and standard gamble (SG)] of living with an NAC deformity. Utility scores for monocular and binocular blindness were determined for validation and comparison. Linear regression and Student’s t test were used for statistical analysis, and significance was set at P < 0.05. Results: There were 103 prospective volunteers included. Utility scores (VAS, TTO, and SG) for NAC deformity were 0.84 ± 0.18, 0.92 ± 0.11, and 0.92 ± 0.11, respectively. Age, gender, and ethnicity were not statistically significant independent predictors of utility scores. Income thresholds of <$10,000 and >$10,000 revealed a statistically significant difference for VAS (P = 0.049) and SG (P = 0.015). Linear regression analysis showed that medical education was directly proportional to the SG and TTO scores (P < 0.05). Conclusions: The absence of NAC in a reconstructed breast can be objectively assessed using utility scores (VAS, 0.84 ± 0.18; TTO, 0.92 ± 0.11; SG, 0.92 ± 0.11). In comparison to prior reported conditions, the quality of life in patients choosing to undergo NAC reconstruction is similar to that of persons living with a nasal deformity or an aging neck requiring rejuvenation. PMID:25973358

  7. Inequality and inequity in healthcare utilization in urban Nepal: a cross-sectional observational study.

    PubMed

    Saito, Eiko; Gilmour, Stuart; Yoneoka, Daisuke; Gautam, Ghan Shyam; Rahman, Md Mizanur; Shrestha, Pradeep Krishna; Shibuya, Kenji

    2016-09-01

    Inequality in access to quality healthcare is a major health policy challenge in many low- and middle-income countries. This study aimed to identify the major sources of inequity in healthcare utilization using a population-based household survey from urban Nepal. A cross-sectional survey was conducted covering 9177 individuals residing in 1997 households in five municipalities of Kathmandu valley between 2011 and 2012. The concentration index was calculated and a decomposition method was used to measure inequality in healthcare utilization, along with a horizontal inequity index (HI) to estimate socioeconomic inequalities in healthcare utilization. Results showed a significant pro-rich distribution of general healthcare utilization in all service providers (Concentration Index: 0.062, P < 0.001; HI: 0.029, P < 0.05) and private service providers (Concentration Index: 0.070, P < 0.001; HI: 0.030, P < 0.05). The pro-rich distribution of probability in general healthcare utilization was attributable to inequalities in the level of household economic status (percentage contribution: 67.8%) and in the self-reported prevalence of non-communicable diseases such as hypertension (36.7%) and diabetes (14.4%). Despite the provision of free services by public healthcare providers, our analysis found no evidence of the poor making more use of public health services (Concentration Index: 0.041, P = 0.094). Interventions to reduce the household economic burden of major illnesses, coupled with improvement in the management of public health facilities, warrant further attention by policy-makers. PMID:26856362

  8. Inequality and inequity in healthcare utilization in urban Nepal: a cross-sectional observational study

    PubMed Central

    Saito, Eiko; Gilmour, Stuart; Yoneoka, Daisuke; Gautam, Ghan Shyam; Rahman, Md Mizanur; Shrestha, Pradeep Krishna; Shibuya, Kenji

    2016-01-01

    Inequality in access to quality healthcare is a major health policy challenge in many low- and middle-income countries. This study aimed to identify the major sources of inequity in healthcare utilization using a population-based household survey from urban Nepal. A cross-sectional survey was conducted covering 9177 individuals residing in 1997 households in five municipalities of Kathmandu valley between 2011 and 2012. The concentration index was calculated and a decomposition method was used to measure inequality in healthcare utilization, along with a horizontal inequity index (HI) to estimate socioeconomic inequalities in healthcare utilization. Results showed a significant pro-rich distribution of general healthcare utilization in all service providers (Concentration Index: 0.062, P < 0.001; HI: 0.029, P < 0.05) and private service providers (Concentration Index: 0.070, P < 0.001; HI: 0.030, P < 0.05). The pro-rich distribution of probability in general healthcare utilization was attributable to inequalities in the level of household economic status (percentage contribution: 67.8%) and in the self-reported prevalence of non-communicable diseases such as hypertension (36.7%) and diabetes (14.4%). Despite the provision of free services by public healthcare providers, our analysis found no evidence of the poor making more use of public health services (Concentration Index: 0.041, P = 0.094). Interventions to reduce the household economic burden of major illnesses, coupled with improvement in the management of public health facilities, warrant further attention by policy-makers. PMID:26856362

  9. A study on the utilization of advanced composites in commercial aircraft wing structure: Executive summary

    NASA Technical Reports Server (NTRS)

    Watts, D. J.

    1978-01-01

    The overall wing study objectives are to study and plan the effort by commercial transport aircraft manufacturers to accomplish the transition from current conventional materials and practices to extensive use of advanced composites in wings of aircraft that will enter service in the 1985-1990 time period. Specific wing study objectives are to define the technology and data needed to support an aircraft manufacturer's commitment to utilize composites primary wing structure in future production aircraft and to develop plans for a composite wing technology program which will provide the needed technology and data.

  10. Toledo Public Schools School Utilization Study, 1980-81 School Year. 2nd Year Study. Elementary School Buildings.

    ERIC Educational Resources Information Center

    Toledo Public Schools, OH.

    In response to declining student enrollment, the Toledo, Ohio public school system conducted a school utilization study involving the evaluation of eight categories of achievement. These categories were: (1) educational adequacy as determined by the ability of the facility to meet the requirements of a good instructional program; (2) an overview…

  11. Nonlinear Optical Properties of Organic and Polymeric Thin Film Materials of Potential for Microgravity Processing Studies

    NASA Technical Reports Server (NTRS)

    Abdeldayem, Hossin; Frazier, Donald O.; Paley, Mark S.; Penn, Benjamin; Witherow, William K.; Bank, Curtis; Shields, Angela; Hicks, Rosline; Ashley, Paul R.

    1996-01-01

    In this paper, we will take a closer look at the state of the art of polydiacetylene, and metal-free phthalocyanine films, in view of the microgravity impact on their optical properties, their nonlinear optical properties and their potential advantages for integrated optics. These materials have many attractive features with regard to their use in integrated optical circuits and optical switching. Thin films of these materials processed in microgravity environment show enhanced optical quality and better molecular alignment than those processed in unit gravity. Our studies of these materials indicate that microgravity can play a major role in integrated optics technology. Polydiacetylene films are produced by UV irradiation of monomer solution through an optical window. This novel technique of forming polydiacetylene thin films has been modified for constructing sophisticated micro-structure integrated optical patterns using a pre-programmed UV-Laser beam. Wave guiding through these thin films by the prism coupler technique has been demonstrated. The third order nonlinear parameters of these films have been evaluated. Metal-free phthalocyanine films of good optical quality are processed in our laboratories by vapor deposition technique. Initial studies on these films indicate that they have excellent chemical, laser, and environmental stability. They have large nonlinear optical parameters and show intrinsic optical bistability. This bistability is essential for optical logic gates and optical switching applications. Waveguiding and device making investigations of these materials are underway.

  12. Magnetic resonance and optical spectroscopic studies of carotenoids

    SciTech Connect

    Kispert, L.D.

    1991-05-01

    It is our goal to study the role of a host lattice in the formation of radicals and excited singlet and triplet states that are relevant to photosynthesis. Particular emphasis is being placed on determining what is special about carotenoids that natural photosynthetic systems require them as antennae as well as for protection. We are thus manipulating the host matrix so as to understand the carotenoid function (protection, quenching, energy transfer and antenna) and the structure of carotenoid cations. To characterize their properties, we have carried out EPR, ENDOR, optical, molecular orbital and electrochemical studies of carotenoids and carotenoid cations produced chemically, electrochemically, radiolytically (x-ray irradiated freon matrices) and photolytically (solution photolysis by excimer radiation) as a function of the host matrix. 36 refs.

  13. Utilizing the MODIS 1.38 micrometer Channel for Cirrus Cloud Optical Thickness Retrievals: Algorithm and Retrieval Uncertainties

    NASA Technical Reports Server (NTRS)

    Meyer, Kerry; Platnick, Steven

    2010-01-01

    The cloud products from the Moderate Resolution Imaging Spectroradiometers (MODIS) on Terra and Aqua have been widely used within the atmospheric research community. The retrieval algorithms, however, oftentimes have difficulty detecting and retrieving thin cirrus, due to sensitivities to surface reflectance. Conversely, the 1.38 micron channel, located within a strong water vapor absorption band, is quite useful for detecting thin cirrus clouds since the signal from the surface can be blocked or substantially attenuated by the absorption of atmospheric water vapor below cirrus. This channel, however, suffers from nonnegligible attenuation due to the water vapor located above and within the cloud layer. Here we provide details of a new technique pairing the 1.38 micron and 1.24 micron channels to estimate the above/in-cloud water vapor attenuation and to subsequently retrieve thin cirrus optical thickness (tau) from attenuation-corrected 1.38 p.m reflectance measurements. In selected oceanic cases, this approach is found to increase cirrus retrievals by up to 38% over MOD06. For these cases, baseline 1.38 micron retrieval uncertainties are estimated to be between 15 and 20% for moderately thick cirrus (tau > 1), with the largest error source being the unknown cloud effective particle radius, which is not retrieved with the described technique. Uncertainties increase to around 90% for the thinnest clouds (tau < 0.5) where instrument and surface uncertainties dominate.

  14. Synthesis of photochromic oligophenylenimines: optical and computational studies.

    PubMed

    Pérez, Armando I Martínez; Alonso, Oscar Coreño; Borbolla, Julián Cruz; Vásquez-Pérez, José M; Alonso, Juan Coreño; Ayala, Karina Alemán; Luna-Bárcenas, Gabriel; Pandiyan, Thangarasu; García, Rosa A Vázquez

    2015-01-01

    Phenyleneimine oligomers 4,4'-(((1E,1'E)-(((1E,1'E)-(1,4-phenylenebis-(azanylylidene))bis(methanylylidene))bis(2,5-bis(octyloxy)-4,1-phenylene))bis(methanylyl-idene))-bis(azanylylidene))dianiline (OIC1MS) and 7,7'-(((1E,1'E)-(((1E,1'E)-((9H-fluorene-2,7-diyl)bis(azanylylidene))bis(methanylylidene))bis(2,5-bis(octyloxy)-4,1phenylene))bis- (methanylylidene))bis(azanylylidene))bis(9H-fluoren-2-amine) (OIC2MS) were prepared by means of conventional and mechanochemical synthesis and characterized by FT-IR, 1H- and 13C-NMR techniques. The optical properties of the compounds were studied in solution by using UV-visible spectroscopy, and the optical effects were analyzed as a function of solvent. The results show that OIC2MS exhibits interesting photochromic properties. Furthermore, the structural and electronic properties of the compounds were analyzed by TD-DFT. It was found that the mechanosynthesis is an efficient method for the synthesis of both tetraimines. PMID:25826785

  15. Development of electro-optical instrumentation for reactor safety studies

    SciTech Connect

    Turko, B.T.; Kolbe, W.F.; Leskovar, B.; Sun, R.K.

    1980-11-01

    The development of new electro-optical instrumentation for reactor safety studies is described. The system measures the thickness of the water film and droplet size and velocity distributions which would be encountered in the annular two-phase flow in a reactor cooling system. The water film thickness is measured by a specially designed capacitance system with a short time constant. Water droplet size and velocity are measured by a subsystem consisting of a continuously pulsed laser light source, a vidicon camera, a video recorder, and an automatic image analyzer. An endoscope system attached to the video camera is used to image the droplets. Each frame is strobed with two accurately spaced uv light pulses, from two sequentially fired nitrogen lasers. The images are stored in the video disk recorder. The modified automatic image analyzer is programmed to digitize the droplet size and velocity distributions. Many special optical, mechanical and electronic system components were designed and fabricated. They are described in detail, together with calibration charts and experimental results.

  16. Theoretical and experimental studies of optically pumped molecular gas lasers

    NASA Astrophysics Data System (ADS)

    Ratanavis, Amarin

    Optically pumped molecular gas lasers based on vibrational-rotational transitions in the infrared spectral region were studied experimentally and theoretically. A model was developed to predict the performance of such lasers and explore their potentials for energy and power scaling. This rate equation model was applied to explore the performance of a second-overtone (pulsed) and a first-overtone (CW) pumped HBr laser. Experimental improvements concerning temperature spectral tuning and frequency stabilization of a Nd:YAG laser that pumped HBr were accomplished. Lasing at 4 microns was demonstrated from such a system. We identified acetylene and hydrogen cyanide as potential laser gases that can be pumped with lasers emitting in the attractive telecommunication C band region at about 1.5 microns. Estimations and fluorescence measurements suggest the possibility of lasing in the 3 micron region. Lasing was demonstrated for the first time with a 5 ns pump pulse from an optical parametric oscillator using traditional cavities. The first gas filled hollow fiber laser based on population inversion was demonstrated with C2H2 and emission in the 3 micron region was observed. An analytical model indicates the possibility of CW lasing with small Stokes shift in both C2H 2 and HCN.

  17. Study of phenanthrene utilizing bacterial consortia associated with cowpea (Vigna unguiculata) root nodules.

    PubMed

    Sun, Ran; Crowley, David E; Wei, Gehong

    2015-02-01

    Many legumes have been selected as model plants to degrade organic contaminants with their special associated rhizosphere microbes in soil. However, the function of root nodules during microbe-assisted phytoremediation is not clear. A pot study was conducted to examine phenanthrene (PHE) utilizing bacteria associated with root nodules and the effects of cowpea root nodules on phytoremediation in two different types of soils (freshly contaminated soil and aged contaminated soil). Cowpea nodules in freshly-contaminated soil showed less damage in comparison to the aged-contaminated soil, both morphologically and ultra-structurally by scanning electron microscopy. The study of polycyclic aromatic hydrocarbon (PAH) attenuation conducted by high performance liquid chromatography revealed that more PAH was eliminated from liquid culture around nodulated roots than nodule-free roots. PAH sublimation and denaturation gradient gel electrophoresis were applied to analyze the capability and diversity of PAH degrading bacteria from the following four parts of rhizo-microzone: bulk soil, root surface, nodule surface and nodule inside. The results indicated that the surface and inside of cowpea root nodules were colonized with bacterial consortia that utilized PHE. Our results demonstrated that root nodules not only fixed nitrogen, but also enriched PAH-utilizing microorganisms both inside and outside of the nodules. Legume nodules may have biotechnological values for PAH degradation. PMID:25601371

  18. The Utility of Neuroimaging Studies for Informing Educational Practice and Policy in Reading Disorders

    PubMed Central

    Black, Jessica M.; Myers, Chelsea A.; Hoeft, Fumiko

    2015-01-01

    Educational neuroscience is an emerging scientific field that brings together researchers from neuroscience, psychology, and education to explore the neurocognitive processes underlying educational practice and theory. In this brief article, we take reading disorder (RD, also known as developmental dyslexia) as an example, and explore trends in neuroimaging research, which may have future implications for educational practice and policy. Specifically, we present two examples that have been central to research efforts in our laboratory: (a) utilizing multimodal neuroimaging to optimize criteria to diagnose RD, and (b) identifying neuroimaging markers that predict future academic outcomes. Such research is faced with important challenges, and rigorous validation is necessary before any claims of the widespread practical utility of neuroimaging can be made. Nevertheless, we contend that neuroimaging studies offer opportunities for providing critical information that could lead to advancing theory of reading and RD. This could in turn lead to better diagnostic criteria and more accurate and earlier identification of RD. PMID:25732015

  19. Studies of optical and biological properties of terrestrial land cover using multispectral linear array technology

    NASA Technical Reports Server (NTRS)

    Barnes, W. L.; Salomonson, V. V.

    1984-01-01

    A series of experiments to study the optical and biological properties of terrestrial land cover are planned for late 1987 using a six-channel imaging spectroradiometer based on newly developed multispectral linear array (MLA) detector technology. Data from selected portions of the Sahel and rain forests of Africa and South America will be used to delineate biomass classes and estimate spherical albedos. A spatial resolution of 15 meters in the four visible-near IR channels and 30 meters in two shortwave IR channels, including a 'new' channel centered at 1.24 micrometers when combined with a spectral width of 20 nm for all channels, will be used to investigate possible improvements in land cover classification. Technology demonstrations include a test of data compression on data quality, the first spaceborne utilization of short wave infrared Schottky barrier Pd2Si detector arrays, and the use of close-butted, multi-array modules with attached spectral filters.

  20. A comparison study of optical coherence elastography and laser Michelson vibrometry

    NASA Astrophysics Data System (ADS)

    Li, Jiasong; Liu, Chih-Hao; Schill, Alexander; Singh, Manmohan; Kistenev, Yury V.; Larin, Kirill V.

    2016-03-01

    Quantitative elastography is a power technique to detect and analyze the changes in biomedical properties of tissues in normal and pathological states. In this study, two noncontact elastography techniques, laser Michelson vibrometry (LMV) and optical coherence elastography (OCE), were utilized to quantify the Young's modulus of tissue-mimicking agar phantoms of various concentrations. Low-amplitude (micrometer scale) elastic waves were induced by a focused air-pulse delivery system and imaged by the respective systems. The Young's modulus as assessed by both elastographic techniques was similar and was compared to the stiffness as measured by uniaxial mechanical testing. The results show that both techniques accurately quantified the elasticity. OCE can provide absolute elastic wave temporal profile, depth-resolved measurement and superior displacement sensitivity compared to LMV, but LMV is significantly cheaper (10X) and easier to implement than OCE.

  1. Utilizing Drumming for American Indians/Alaska Natives with Substance Use Disorders: A Focus Group Study

    PubMed Central

    Dickerson, Daniel; Robichaud, Francis; Teruya, Cheryl; Nagaran, Kathleen; Hser, Yih-Ing

    2013-01-01

    Background Drumming has been utilized among American Indian/Alaska Native (AI/AN) tribes for centuries to promote healing and self-expression. Drum-Assisted Recovery Therapy for Native Americans (DARTNA), currently under development, is a substance abuse treatment utilizing drumming as a core component. Objectives Focus groups were conducted to assist in the development of the DARTNA protocol. Feedback obtained from these focus groups will inform a subsequent pretest of DARTNA and an empirical study analyzing its effectiveness. Methods Three focus groups were conducted among AIs/ANs with substance use disorders (n = 6), substance abuse treatment providers (n = 8), and a community advisory board (n = 4) to solicit feedback prior to a pretest of the DARTNA protocol. Results Overall, participants indicated that DARTNA could be beneficial for AIs/ANs with substance use disorders. Four overarching conceptual themes emerged across the focus groups: (1) benefits of drumming, (2) importance of a culture-based focus, (3) addressing gender roles in drumming activities, and (4) providing a foundation of common AI/AN traditions. Conclusions The DARTNA protocol is a potentially beneficial and culturally appropriate substance abuse treatment strategy for AIs/ANs. In order to optimize the potential benefits of a substance abuse treatment protocol utilizing drumming for AIs/ANs, adequate attention to tribal diversity and gender roles is needed. Scientific Significance Due to the shortage of substance abuse treatments utilizing traditional healing activities for AIs/ANs, including drumming, results from this study provide an opportunity to develop an intervention that may meet the unique treatment needs of AIs/ANs. PMID:22931086

  2. The APOSTEL recommendations for reporting quantitative optical coherence tomography studies

    PubMed Central

    Cruz-Herranz, Andrés; Balk, Lisanne J.; Oberwahrenbrock, Timm; Saidha, Shiv; Martinez-Lapiscina, Elena H.; Lagreze, Wolf A.; Schuman, Joel S.; Villoslada, Pablo; Calabresi, Peter; Balcer, Laura; Petzold, Axel; Green, Ari J.; Paul, Friedemann; Brandt, Alexander U.

    2016-01-01

    Objective: To develop consensus recommendations for reporting of quantitative optical coherence tomography (OCT) study results. Methods: A panel of experienced OCT researchers (including 11 neurologists, 2 ophthalmologists, and 2 neuroscientists) discussed requirements for performing and reporting quantitative analyses of retinal morphology and developed a list of initial recommendations based on experience and previous studies. The list of recommendations was subsequently revised during several meetings of the coordinating group. Results: We provide a 9-point checklist encompassing aspects deemed relevant when reporting quantitative OCT studies. The areas covered are study protocol, acquisition device, acquisition settings, scanning protocol, funduscopic imaging, postacquisition data selection, postacquisition data analysis, recommended nomenclature, and statistical analysis. Conclusions: The Advised Protocol for OCT Study Terminology and Elements recommendations include core items to standardize and improve quality of reporting in quantitative OCT studies. The recommendations will make reporting of quantitative OCT studies more consistent and in line with existing standards for reporting research in other biomedical areas. The recommendations originated from expert consensus and thus represent Class IV evidence. They will need to be regularly adjusted according to new insights and practices. PMID:27225223

  3. Analytical study of acousto/optical holography-interfacing methods for acoustical and optical holography NDT research

    NASA Technical Reports Server (NTRS)

    El-Sum, H. M. A.

    1976-01-01

    The international status of the art of acousto optical imaging techniques adaptable to nondestructive testing and, interfacing methods for acoustical and optical holography in nondestructive testing research are studied. Evaluation of 20 different techniques encompassed investigation of varieties of detectors and detection schemes, all of which are described and summarized. Related investigation is reported in an Appendix. Important remarks on image quality, factors to be considered in designing a particular system, and conclusions and recommendations are presented. Three bibliographies are included.

  4. A study on the utilization of advanced composites in commercial aircraft wing structure

    NASA Technical Reports Server (NTRS)

    Watts, D. J.

    1978-01-01

    A study was conducted to define the technology and data needed to support the introduction of advanced composite materials in the wing structure of future production aircraft. The study accomplished the following: (1) definition of acceptance factors, (2) identification of technology issues, (3) evaluation of six candidate wing structures, (4) evaluation of five program options, (5) definition of a composite wing technology development plan, (6) identification of full-scale tests, (7) estimation of program costs for the total development plan, (8) forecast of future utilization of composites in commercial transport aircraft and (9) identification of critical technologies for timely program planning.

  5. Stem Cell Ophthalmology Treatment Study (SCOTS) for retinal and optic nerve diseases: a preliminary report

    PubMed Central

    Weiss, Jeffrey N.; Levy, Steven; Malkin, Alexis

    2015-01-01

    In this report, we present the results of a single patient with optic neuropathy treated within the Stem Cell Ophthalmology Treatment Study (SCOTS). SCOTS is an Institutional Review Board approved clinical trial and is the largest ophthalmology stem cell study registered at the National Institutes of Health to date- www.clinicaltrials.gov Identifier NCT 01920867. SCOTS utilizes autologous bone marrow-derived stem cells in the treatment of optic nerve and retinal diseases. Pre- and post-treatment comprehensive eye exams were independently performed at the Wilmer Eye Institute at the Johns Hopkins Hospital, USA. A 27 year old female patient had lost vision approximately 5 years prior to enrollment in SCOTS. Pre-treatment best-corrected visual acuity at the Wilmer Eye Institute was 20/800 Right Eye (OD) and 20/4,000 Left Eye (OS). Four months following treatment in SCOTS, the central visual acuity had improved to 20/100 OD and 20/40 OS. PMID:26199618

  6. Do physician-payment mechanisms affect hospital utilization? A study of Health Service Organizations in Ontario.

    PubMed Central

    Hutchison, B; Birch, S; Hurley, J; Lomas, J; Stratford-Devai, F

    1996-01-01

    OBJECTIVES: To determine whether payment of primary care physicians based on capitation, with an additional incentive payment for low hospital-utilization rates, resulted in lower hospital-utilization rates among patients of these physicians than among patients of physicians still paid on a fee-for-service basis. DESIGN: Retrospective cohort study. SETTING: Capitation-based and fee-for-service primary care practices in Ontario. SUBJECTS: Thirty-nine physicians whose method of payment was converted from fee-for-service to capitation during the period from June 1985 to January 1989 and 7 physicians who remained in fee-for-service practice, two of whom were matched with one physician in capitation-based practice on the basis of practice location, type of practice (academic v. community), hours of practice (part-time v. full-time), years since graduation, physician group size, practice size (number of patients), type of group (primary care v. multispecialty), sex, certification in family medicine, country of graduation (Canada v. other) and age. One physician in capitation-based practice was matched with only one physician in fee-for-service practice. OUTCOME MEASURES: Annual hospital-utilization rates (hospital separations or hospital days per 1000 patients in each practice) for the physicians paid on a capitation basis 3 years before, 1 year before and 3 years after they converted from fee-for-service payment and at corresponding periods for the matched physicians still paid on a fee-for-service basis. RESULTS: The mean annual rate of hospital days used, adjusted for the age and sex of patients as well as for their social-program-recipient status, fell from 1085 per 1000 patients (3 years before the conversion date) to 1030 (1 year before conversion) and to 954 (3 years after conversion) in capitation-based practices. For the matched physicians in fee-for-service practice, the rates during the corresponding periods were 1085, 1035 and 956 hospital days per 1000

  7. Traceability study of optical fiber degree of polarization (DOP) measurement

    NASA Astrophysics Data System (ADS)

    Xu, Nan; Li, Jianwei; Li, Jian; Zhang, Zhixin

    2013-09-01

    Degree of polarization (DOP) is an important physical quantity for describing the optical polarization effect and is widely applied in optical fiber communication, optical fiber gyro and the related technologies. Currently, the optical polarization degree tester for the purpose of communication uses mainly two kinds of measurement methods: Stokes vector method and extremum method. At present, there isn't a standard to measure the accuracy and consistency of DOP parameter measurement by the devices listed above, affecting seriously the application of DOP parameter measurement in the fields of optical fiber gyro and optical fiber communication. So, it is urgent to table the accurate guarantees to trace the source of quantitative values of the DOP measuring devices and testers. In this paper, the polarization beam combination method is raised to research and manufacture the standard optical fiber light source device with the variable DOP, and an indicated error measurement has been conducted for a DOP meter. A kind of standard optical fiber light source device that uses a single light source to realize the variable DOP is put forward. It is used to provide the accurate and variable optical fiber polarization degree light with a scope of 0~100%. It is used to calibrate the DOP meters and widely applied in the field of national defense and optical communication fields. By using the standard optical power meter, DOP value by which the optical power meter calculates the optical signal can be measured, which will be used ultimately for calibration of the DOP meter. A measurement uncertainty of 0.5% is obtained using the polarization beam combination method.

  8. Real-time experimental demonstrations of software reconfigurable optical OFDM transceivers utilizing DSP-based digital orthogonal filters for SDN PONs.

    PubMed

    Duan, X; Giddings, R P; Bolea, M; Ling, Y; Cao, B; Mansoor, S; Tang, J M

    2014-08-11

    Real-time optical OFDM (OOFDM) transceivers with on-line software-controllable channel reconfigurability and transmission performance adaptability are experimentally demonstrated, for the first time, utilizing Hilbert-pair-based 32-tap digital orthogonal filters implemented in FPGAs. By making use of an 8-bit DAC/ADC operating at 2GS/s, an oversampling factor of 2 and an EML intensity modulator, the demonstrated RF conversion-free transceiver supports end-to-end real-time simultaneous adaptive transmissions, within a 1GHz signal spectrum region, of a 2.03Gb/s in-phase OOFDM channel and a 1.41Gb/s quadrature-phase OOFDM channel over a 25km SSMF IMDD system. In addition, detailed experimental explorations are also undertaken of key physical mechanisms limiting the maximum achievable transmission performance, impacts of transceiver's channel multiplexing/demultiplexing operations on the system BER performance, and the feasibility of utilizing adaptive modulation to combat impairments associated with low-complexity digital filter designs. Furthermore, experimental results indicate that the transceiver incorporating a fixed digital orthogonal filter DSP architecture can be made transparent to various signal modulation formats up to 64-QAM. PMID:25321051

  9. Stem Cell Ophthalmology Treatment Study (SCOTS) for retinal and optic nerve diseases: a case report of improvement in relapsing auto-immune optic neuropathy.

    PubMed

    Weiss, Jeffrey N; Levy, Steven; Benes, Susan C

    2015-09-01

    We present the results from a patient with relapsing optic neuropathy treated within the Stem Cell Ophthalmology Treatment Study (SCOTS). SCOTS is an Institutional Review Board approved clinical trial and has become the largest ophthalmology stem cell study registered at the National Institutes of Health to date (www.clinicaltrials.gov Identifier NCT 01920867). SCOTS utilizes autologous bone marrow-derived stem cells (BMSCs) for treatment of retinal and optic nerve diseases. Pre-treatment and post-treatment comprehensive eye exams of a 54 year old female patient were performed both at the Florida Study Center, USA and at The Eye Center of Columbus, USA. As a consequence of a relapsing optic neuritis, the patient's previously normal visual acuity decreased to between 20/350 and 20/400 in the right eye and to 20/70 in the left eye. Significant visual field loss developed bilaterally. The patient underwent a right eye vitrectomy with injection of BMSCs into the optic nerve of the right eyeand retrobulbar, subtenon and intravitreal injection of BMSCs in the left eye. At 15 months after SCOTS treatment, the patient's visual acuity had improved to 20/150 in the right eye and 20/20 in the left eye. Bilateral visual fields improved markedly. Both macular thickness and fast retinal nerve fiber layer thickness were maximally improved at 3 and 6 months after SCOTS treatment. The patient also reduced her mycophenylate dose from 1,500 mg per day to 500 mg per day and required no steroid pulse therapy during the 15-month follow up. PMID:26604914

  10. Stem Cell Ophthalmology Treatment Study (SCOTS) for retinal and optic nerve diseases: a case report of improvement in relapsing auto-immune optic neuropathy

    PubMed Central

    Weiss, Jeffrey N.; Levy, Steven; Benes, Susan C.

    2015-01-01

    We present the results from a patient with relapsing optic neuropathy treated within the Stem Cell Ophthalmology Treatment Study (SCOTS). SCOTS is an Institutional Review Board approved clinical trial and has become the largest ophthalmology stem cell study registered at the National Institutes of Health to date (www.clinicaltrials.gov Identifier NCT 01920867). SCOTS utilizes autologous bone marrow-derived stem cells (BMSCs) for treatment of retinal and optic nerve diseases. Pre-treatment and post-treatment comprehensive eye exams of a 54 year old female patient were performed both at the Florida Study Center, USA and at The Eye Center of Columbus, USA. As a consequence of a relapsing optic neuritis, the patient's previously normal visual acuity decreased to between 20/350 and 20/400 in the right eye and to 20/70 in the left eye. Significant visual field loss developed bilaterally. The patient underwent a right eye vitrectomy with injection of BMSCs into the optic nerve of the right eyeand retrobulbar, subtenon and intravitreal injection of BMSCs in the left eye. At 15 months after SCOTS treatment, the patient's visual acuity had improved to 20/150 in the right eye and 20/20 in the left eye. Bilateral visual fields improved markedly. Both macular thickness and fast retinal nerve fiber layer thickness were maximally improved at 3 and 6 months after SCOTS treatment. The patient also reduced her mycophenylate dose from 1,500 mg per day to 500 mg per day and required no steroid pulse therapy during the 15-month follow up. PMID:26604914

  11. Detection of immunoglobulins in a laser induced fluorescence system utilizing polydimethysiloxane microchips with advanced surface and optical properties.

    PubMed

    Schrott, Walter; Nebyla, Marek; Přibyl, Michal; Snita, Dalimil

    2011-01-01

    We developed an automated laser induced fluorescence system utilizing microfluidic chips for detection and quantification of immunoglobulins. Microchips were fabricated from polydimethysiloxane (PDMS) using the so-called "prepolymerization technique." The microchip structure helped minimize the effects of PDMS autofluorescence and light scattering. Furthermore, a thin and uniform PDMS layer forming the top of the microchip enabled proper focusing and collection of the excitation beam and the emitted fluorescence, respectively. The developed system was tested for the detection of mouse immunoglobulins. The capturing antibodies were immobilized on internal microchannel walls in the form of a polyelectrolyte. We clearly show that this immobilization technique, if correctly realized, gives results with high reproducibility. After sample incubation and washing, secondary antibodies labeled by fluorescein isothiocyanate were introduced into microchannels to build a detectable complex. We show that mouse antibodies can be quantified in a wide concentration range, 0.01-100 μg ml(-1). The lower detection limit was below 0.001 μg ml(-1) (6.7 pM). The developed laser induced fluorescence (LIF) apparatus is relatively cheap and easy to construct. The total cost of the developed LIF detector is lower than a typical price of plate readers. If compared to classical ELISA (enzyme linked immunosorbent assay) plate systems, the detection of immunoglobulins or other proteins in the developed PDMS microfluidic device brings other important benefits such as reduced time demands (10 min incubation) and low reagent consumption (less than 1 μl). The cost of the developed PDMS chips is comparable with the price of commercial ELISA plates. The main troubleshooting related to the apparatus development is also discussed in order to help potential constructors. PMID:21359027

  12. Utilizing Underwater Three-Dimensional Modeling to Enhance Ecological and Biological Studies of Coral Reefs

    NASA Astrophysics Data System (ADS)

    Burns, J. H. R.; Delparte, D.; Gates, R. D.; Takabayashi, M.

    2015-04-01

    The structural complexity of coral reefs profoundly affects the biodiversity, productivity, and overall functionality of reef ecosystems. Conventional survey techniques utilize 2-dimensional metrics that are inadequate for accurately capturing and quantifying the intricate structural complexity of scleractinian corals. A 3-dimensional (3D) approach improves the capacity to accurately measure architectural complexity, topography, rugosity, volume, and other structural characteristics that play a significant role in habitat facilitation and ecosystem processes. This study utilized Structure-from-Motion (SfM) photogrammetry techniques to create 3D mesh models for several Hawaiian corals that represent distinct morphological phenotypes. The orthophotos and digital elevation models generated from the SfM process were imported into geospatial analysis software in order to quantify several metrics pertaining to 3D complexity that are known to affect ecosystem biodiversity and productivity. The 3D structural properties of the reconstructed coral colonies were statistically analyzed to determine if the each species represents a unique morpho-functional group. The SfM reconstruction techniques described in this paper can be utilized for an array of research purposes to improve our understanding of how changes in coral composition affect habitat structure and ecological processes in coral reef ecosystems.

  13. Economic feasibility of utilizing urban wood: case study of the San Francisco Bay area

    SciTech Connect

    Kent, M.; Wagar, J.A.; Dost, W.A.

    1982-09-01

    Rising costs of wood, energy and solid waste disposal have created growing interest in utilizing urban wood. As a model for wider application, we estimated the economic feasibility of a facility located in Oakland, California which would integrate the utilization and disposal of urban wood. A related study used questionnaires and interviews with producers of wood-waste as well as field visits, published information, and contacts with professional and trade organizations to estimate the supply of woodwaste in the San Francisco Bay area. The supply available to an Oakland utilization facility was estimated by multiplying the total Bay area supply by the percentage of the area's population projected to be closer to the facility than to a sanitary landfill by 1982. Potential users of hogged chips and hardwood blocks and slabs were contacted to determine how much material they would be willing to buy, at what prices, and under what conditions. Fees that produce would be willing to pay to dispose of wastewood were also estimated, as were costs of producing hogged chips for fuel or composting and high-quality hardwood material for crafts use. Potential revenues were estimated by subtracting processing and transportation costs from sales prices and dump fees. An Oakland hogging facility producing chips for fuel or sewage composting was judged as likely to be profitable with the chance of profit increased by adding a chainsaw mill to convert quality hardwoods into material for use by woodworkers. The procedures used for Oakland should be applicable to other communities and regions.

  14. Artificial lightweight aggregates as utilization for future ashes - A case study.

    PubMed

    Sarabèr, Angelo; Overhof, Robert; Green, Terry; Pels, Jan

    2012-01-01

    In the future, more electricity in the Netherlands will be produced using coal with co-combustion. Due to this, the generated annual ash volume will increase and the chemical composition will be influenced. One of the options for utilization if present markets are saturated and for use of fly ashes with different compositions, is as raw material for lightweight aggregates. This was selected as one of the best utilizations options regarding potential ash volume to be applied, environmental aspects and status of technology. Because of this, a study has been performed to assess the potential utilization of fly ash for the production of lightweight aggregate. Lightweight aggregate has been produced in a laboratory scale rotary kiln. The raw material consisted of class F fly ash with high free lime content. An addition of 8% clay was necessary to get green pellets with sufficient green strength. The basic properties of the produced lightweight aggregate and its behaviour in concrete have been investigated. The concrete has a good compressive strength and its leaching behaviour meets the most stringent requirements of Dutch environmental regulations. The carbon foot print of concrete will be negatively influenced if only the concrete itself is taken into account, but the reduction of the volume weight has advantages regarding design, transport emissions and isolation properties which may counteract this. In the Dutch situation the operational costs are higher than expected potential selling price for the LWA, which implies that the gate fee for the fly ash is negative. PMID:21963657

  15. Drug Utilization Study in Medical Emergency Unit of a Tertiary Care Hospital in North India

    PubMed Central

    Kaur, Sharonjeet; Rajagopalan, Sujit; Bhalla, Ashish; Pandhi, Promila; Malhotra, Samir

    2014-01-01

    Objective. To generate data on the drug utilization pattern and cost of drug treatment and to determine the rationality of prescriptions. Methods. A retrospective cross-sectional drug utilization study was conducted in the medical emergency unit of our hospital. Patient case records were reviewed to extract data on the pattern of drug use. Cost of drug treatment for the emergency visit was calculated by referring to the cost mentioned in Monthly Index of Medical Specialties and the rationality of prescriptions was evaluated using WHO core indicators of drug utilization. Results. 1100 case records were reviewed. Majority of patients received proton pump inhibitors followed by multivitamins. The median cost per prescription was 119.23$ (7.32$–7663.46$). Majority (49.9%) of drug cost was driven by antibiotics alone. An average of 4.9 drugs was prescribed per prescription. There were 14.89% encounters with antibiotics. 75.17% of the drugs were given as injectables and only 29.27% of the drugs were prescribed as generics. Conclusion. There is need to rationalize the drug therapy in terms of increasing prescribing of drugs by generic name and to avoid overuse of PPIs and multivitamins in emergency unit. Also the hospital pharmacy should be encouraged to procure more cost effective alternative antibiotics in future. PMID:24883208

  16. Chiropractic utilization in BMX athletes at the UCI World Championships: a retrospective study

    PubMed Central

    Konczak, Clark Ryan

    2010-01-01

    Objective To examine paramedical (chiropractic, physiotherapy and massage therapy) utilization among high-level BMX athletes following sport-related injury at the 2007 UCI World Championships. Methods Retrospective analysis was conducted on a dataset from international male and female BMX athletes (n = 110) who sustained injury in training and competition at the 2007 BMX World Championships. Results Fifty percent of individuals aged 8–17 presented to a chiropractor versus 32% to physiotherapists and 18% to massage therapists. There was a significant difference in paramedical practitioner choice when comparing the sample across the different locations of injury. Specifically, the proportion of individuals presenting for treatment to chiropractors (84%) was much higher than to physiotherapists/massage therapists (16%) for spine or torso complaints. Conclusion Utilization of chiropractors by BMX athletes may be higher than utilization of other paramedical professionals as suggested by this study. Chiropractors appear to be the paramedical practitioner of choice in regards to spine and torso related complaints. PMID:21120016

  17. Topographical studies on GNF crystals of non linear optical origin

    NASA Astrophysics Data System (ADS)

    Khandpekar, M. M.; Pati, S. P.

    2013-02-01

    α-glycine has been combined with equal amount of nitric acid and hydrofluoric acid to form GNF crystals. Transparent and elongated crystals of appreciable sizes (2.5 cm length) useful for dislocation studies have been obtained from solution by slow evaporation in 3-4 weeks time. Crystals were found to be delicate and care is needed while handling them. The external geometry of the crystals was found to vary with composition. Glacial acetic acid (GAA) is found to be universal etching agent. GAA produces well defined elongated etch pits on the habit faces and curved triangular pits on cleavage faces in 15 seconds time. Evidence of impurity inclusions and pits on these inclusions have been detected. The orientation of pits on partial cleavage faces are clearly seen to differ. Occasional presence of long domain lines crossing the field of view has been observed. The curvature of pits edges indicates an optically active material with lower symmetry.

  18. Optical spectroscopy study of Weyl Semimetal NbP

    NASA Astrophysics Data System (ADS)

    Yang, Jeremy; Jiang, Yuxuan; Dun, Zhiling; Zhou, Haidong; Smirnov, Dmitry; Jiang, Zhigang

    Weyl semimetals have attracted much interest lately because of its unique band structure, where conduction band and valence band touch at discrete points. Here, we report on optical spectroscopy study of Weyl semimetal NbP, seeking evidence for the existence of Weyl fermions. Specifically, using Raman spectroscopy we investigate the anisotropic response of Raman-active phonon modes in NbP and compare with Quantum Espresso simulations. Using magneto-infrared spectroscopy in a high magnetic field up to 17.5T, we observe several Landau level transitions and compare with the theoretical model of three-dimensional massless Dirac/Weyl fermions. By combining our data with low-temperature magneto-transport measurement, the magnetic field dispersion of Landau levels in NbP is obtained.

  19. Numerical study of grating-assisted optical diffraction tomography

    SciTech Connect

    Chaumet, Patrick C.; Belkebir, Kamal; Sentenac, Anne

    2007-07-15

    We study the resolution of an optical diffraction tomography system in which the objects are either in an homogeneous background or deposited onto a glass prism, a prism surmounted by a thin metallic film or a prism surmounted by a metallic film covered by a periodically nanostructured dielectric layer. For all these configurations, we present an inversion procedure that yields the map of the relative permittivity of the objects from their diffracted far field. When multiple scattering can be neglected, we show that the homogeneous, prism, and metallic film configurations yield a resolution about {lambda}/4 while the grating substrate yields a resolution better than {lambda}/10. When Born approximation fails, we point out that it is possible to neglect the coupling between the object and the substrate and account solely for the multiple scattering within the objects to obtain a satisfactory reconstruction. Last, we present the robustness of our inversion procedure to noise.

  20. Carotenoid cation radicals: electrochemical, optical, and EPR study

    SciTech Connect

    Grant, J.L.; Kramer, V.J.; Ding, R.; Kispert, L.D.

    1988-03-30

    The general aim of this investigation is to determine whether carotenoid cation radicals can be produced, and stabilized, electrochemically. Hence, the authors have undertaken a detailed study of the electrooxidation of various carotenoids (..beta..-carotene (I), ..beta..-apo-8'-carotenal (II), and canthaxanthin (III) using the techniques of cyclic voltammetry, controlled-potential electrolysis (cpe) in conjunction with optical spectroscopy, and EPR spectroscopy coupled with in situ electrolysis. They report the successful generation of carotenoid cation radicals via electrochemical oxidation and, furthermore, the stabilization of these radicals for several minutes in CH/sub 2/Cl/sub 2/ and C/sub 2/H/sub 4/Cl/sub 2/ solvents.

  1. Mechanical properties of a giant liposome studied using optical tweezers

    NASA Astrophysics Data System (ADS)

    Shitamichi, Yoko; Ichikawa, Masatoshi; Kimura, Yasuyuki

    2009-09-01

    The mechanical properties of a micrometer-sized giant liposome are studied by deforming it from the inside using dual-beam optical tweezers. As the liposome is extended, its shape changes from a sphere to a lemon shape, and finally, a tubular part is generated. The surface tension σ and the bending rigidity κ of the lipid membrane are obtained from the measured force-extension curve. In a one-phase liposome, it was found that σ increases as the charged component increases but κ remains approximately constant. In a two-phase liposome, the characteristic deformation and the force-extension curve differ from those observed for the one-phase liposome.

  2. Synthesis and optical study of barium magnesium aluminate blue phosphors

    NASA Astrophysics Data System (ADS)

    Jeet, Suninder; Sharma, Manoj; Pandey, O. P.

    2015-05-01

    Europium doped barium magnesium aluminate (BaMgAl10O17:Eu2+) phosphor was prepared via solution combustion method at 550°C using urea as a fuel. Morphological and optical properties of the prepared sample was studied by X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Photoluminescence spectroscopy (PL). XRD result showed the formation of pure phase BaMgAl10O17(JCPDS 26-0163) along with an additional phase BaAl2O4(JCPDS 01-082-1350). TEM image indicated the formation of faceted particles with average particle size 40 nm. From PL spectra, a broad emission band obtained at about 450 nm attributes to 4f6 5d → 4f7 transition of Eu2+ which lies in the blue region of the visible spectrum.

  3. Using Optical Tweezers to Study Cell Mechanics during Airway Reopening

    NASA Astrophysics Data System (ADS)

    Yalcin, Huseyin; Wang, Jing; Ghadiali, Samir; Ou-Yang, H. Daniel

    2006-03-01

    Patients suffering from the acute respiratory distress syndrome (ARDS) must be mechanically ventilated in order to survive. However, these ventilation protocols may generate injurious hydrodynamic stresses especially during low tidal volume (VT) ventilation when the flow of micron-sized air bubbles displace the surrounding liquid. In-vitro studies in our lab revealed that microbubble flows can severally damage lung epithelial cells (EC). The degree of injury was elevated for sub-confluent monolayers in small channel heights. Under these conditions, the micromechanics of individual EC may influence the degree of cellular injury. To investigate the role of cell mechanics, we used an oscillating Optical Tweezers (OT) technique to measure the intrinsic mechanical properties of EC before and after the flow of microbubbles. Knowledge of how the EC's micromechanical properties influence cell viability may lead to the development of novel treatment therapies that enhance the EC's ability to withstand injurious hydrodynamic stresses during ventilation treatment.

  4. Synthesis and optical study of barium magnesium aluminate blue phosphors

    SciTech Connect

    Jeet, Suninder Pandey, O. P.; Sharma, Manoj

    2015-05-15

    Europium doped barium magnesium aluminate (BaMgAl{sub 10}O{sub 17}:Eu{sup 2+}) phosphor was prepared via solution combustion method at 550°C using urea as a fuel. Morphological and optical properties of the prepared sample was studied by X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Photoluminescence spectroscopy (PL). XRD result showed the formation of pure phase BaMgAl{sub 10}O{sub 17}(JCPDS 26-0163) along with an additional phase BaAl{sub 2}O{sub 4}(JCPDS 01-082-1350). TEM image indicated the formation of faceted particles with average particle size 40 nm. From PL spectra, a broad emission band obtained at about 450 nm attributes to 4f{sup 6} 5d → 4f{sup 7} transition of Eu{sup 2+} which lies in the blue region of the visible spectrum.

  5. Optical Study of Liquid Crystal Doped with Multiwalled Carbon Nanotube

    NASA Astrophysics Data System (ADS)

    Gharde, Rita A.; Thakare, Sangeeta Y.

    2014-11-01

    Liquid crystalline materials have been useful for display devices i.e watches, calculators, automobile dashboards, televisions, multi media projectors etc. as well as in electro tunable lasers, optical fibers and lenses. Carbon nanotube is chosen as the main experimental factor in this study as it has been observed that Carbon Nano Tube influence the existing properties of liquid crystal host and with the doping of CNT can enhance1 the properties of LC. The combination of carbon nanotube (CNT) and liquid crystal (LC) materials show considerable interest in the scientific community due to unique physical properties of CNT in liquid crystal. Dispersion of CNTs in LCs can provide us a cheap, simple, versatile and effective means of controlling nanotube orientation on macroscopic scale with no restrictions on nanotube type. LCs have the long range orientational order rendering them to be anisotropic phases. If CNTs can be well dispersed in LC matrix, they will align with their long axes along the LC director to minimize distortions of the LC director field and the free energy. In this paper, we doped liquid crystal (Cholesteryl Nonanoate) by a small amount of multiwall carbon nanotube 0.05% and 0.1% wt. We found that by adding carbon nanotube to liquid crystals the melting point of the mixture is decreased but TNI is increased. It has been also observed that with incereas in concentration of carbon nanotube into liquid crystal shows conciderable effect on LC. The prepared samples were characterized using various techniques to study structural, thermal and optical properties i.e PMS, FPSS, UV-Vis spectroscopy, FT-IR measurements, and DTA.

  6. Utility of MODIS Aerosol Optical Depth for Estimating PM2.5 Exposure in Environmental Public Health Surveillance

    NASA Technical Reports Server (NTRS)

    Al-Hamdan, Mohammad; Crosson, William; Limaye, Ashutosh; Rickman, Doug; Quattrochi, Dale; Estes, Maury; Adeniyi, Kafayat; Qualters, Judith; Niskar, Amanda Sue

    2006-01-01

    , including PM(2.5). Thus, HELIX-Atlanta is focusing on methods for characterizing population exposure to PM(2.5) for the Atlanta metropolitan area that could be used in on-going surveillance. While use of the Air Quality System, (AQS) PM(2.5) data alone could meet HELIX Atlanta, specifications, there are only five AQS sites in the Atlanta area, thus the spatial coverage is not ideal. Also, the AQS ground observations are made at time intervals ranging from one hour to six days leaving some temporal gaps. NASA Moderate Resolution Imaging Spectroradiometer (MODIS) satellite Aerosol Optical Depth (AOD) data have the potential for estimating daily ground level PM(2.5) at 10 km resolution over the metropolitan Atlanta area supplementing the AQS ground observations and filling their spatial and temporal gaps.

  7. An assessment of the utility of optically-stimulated luminescence to date sediments from Lakes Malawi, Bosumtwi, and Tanganyika, Africa

    NASA Astrophysics Data System (ADS)

    Gomez, J.; Forman, S. L.; Pierson, J.; Scholz, C.; Peck, J.; Heil, C.; King, J.; Shanahan, T.; Overpeck, J.; Koeberl, C.; Milkereit, B.

    2005-12-01

    An exciting recent development in geochronology is the advent of optically-stimulated luminescence (OSL) for dating late Quaternary sediments. OSL signal of mineral grains is reset by exposure to sunlight prior to deposition and a time-sensitive charge is acquired from exposure to ionizing radiation post burial. The OSL signal is highly sensitive to solar resetting, with background counts rendered after few minutes of sunlight exposure. OSL geochronology can yield decadal resolution in the past 1000 years, a period of limited precision for radiocarbon dating and potentially date sediment spanning the past 200 to 400 ka. Nearly continuous sedimentary records from African lakes provide unparalleled opportunities to develop new OSL dating approaches to constrain hydro-climatic events in the tropics. A variety of OSL geochronologic approaches are attempted for sediments from Lakes Malawi, Bosumtwi and Tanganyika providing an internal test of reproducibility. Accuracy is assessed by OSL dating levels with radiocarbon ages and with correlated chronologic control e.g. from the sediment magnetic signature or sediment carbon to atmosphere methane relations. The fine-grained (3-11 micron) polymineral and quartz fractions and for coarser levels the quartz fine sand is extracted for dating. Additive and regenerative dose procedures using multiple and single aliquots under blue, green and infrared light exposure are used to estimate the post-burial paleodose. A regenerative procedure with dose normalization and stepped preheating (140-180° C) provides a particularly robust approach for dating sediments greater than 75 ka. OSL emissions for sediment from Lake Malawi for the past ca. 100 ka are not at saturated dose and are amenable for dating by a variety of methods. In contrast sediments from Lake Bosumtwi, with a probable Sahel dust source, exhibit saturation in OSL signal for sediments ca. 100 ka old, necessitating the using of regenerative approaches. The concordance

  8. A Study of the Utilization Patterns of an Elementary School-Based Health Clinic over a 5-Year Period

    ERIC Educational Resources Information Center

    Johnson, Veda; Hutcherson, Valerie

    2006-01-01

    The purpose of this study was to determine the utilization pattern of an elementary school-based clinic over a 5-year period. It involved a retrospective analysis of computer-based data for all patient visits during this study period. Results revealed high clinic utilization with an average of over 5 encounters for all users each year. The most…

  9. 78 FR 68461 - Guidance for Industry: Studies To Evaluate the Utility of Anti-Salmonella Chemical Food Additives...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-14

    ... Guidance for Industry: Studies to Evaluate the Utility of Anti-Salmonella Chemical Food Additives in Feeds... HUMAN SERVICES Food and Drug Administration Guidance for Industry: Studies To Evaluate the Utility of Anti- Salmonella Chemical Food Additives in Feeds; Request for Comments AGENCY: Food and...

  10. High energy laser optics manufacturing: a preliminary study

    SciTech Connect

    Baird, E.D.

    1980-07-01

    This report presents concepts and methods, major conclusions, and major recommendations concerning the fabrication of high energy laser optics (HELO) that are to be machined by the Large Optics Diamond Turning Machine (LODTM) at the Lawrence Livermore National Laboratory (LLNL). Detailed discussions of concepts and methods proposed for metrological operations, polishing of reflective surfaces, mounting of optical components, construction of mirror substrates, and applications of coatings are included.

  11. Improving Mars-GRAM: Increasing the Accuracy of Sensitivity Studies at Large Optical Depths

    NASA Technical Reports Server (NTRS)

    Justh, Hilary L.; Justus, C. G.; Badger, Andrew M.

    2010-01-01

    Extensively utilized for numerous mission applications, the Mars Global Reference Atmospheric Model (Mars-GRAM) is an engineering-level atmospheric model. In a Monte-Carlo mode, Mars-GRAM's perturbation modeling capability is used to perform high fidelity engineering end-to-end simulations for entry, descent, and landing (EDL). Mars-GRAM has been found to be inexact when used during the Mars Science Laboratory (MSL) site selection process for sensitivity studies for MapYear=0 and large optical depth values such as tau=3. Mars-GRAM is based on the NASA Ames Mars General Circulation Model (MGCM) from the surface to 80 km altitude. Mars-GRAM with the MapYear parameter set to 0 utilizes results from a MGCM run with a fixed value of tau=3 at all locations for the entire year. Imprecise atmospheric density and pressure at all altitudes is a consequence of this use of MGCM with tau=3. Density factor values have been determined for tau=0.3, 1 and 3 as a preliminary fix to this pressure-density problem. These factors adjust the input values of MGCM MapYear 0 pressure and density to achieve a better match of Mars-GRAM MapYear 0 with Thermal Emission Spectrometer (TES) observations for MapYears 1 and 2 at comparable dust loading. These density factors are fixed values for all latitudes and Ls and are included in Mars-GRAM Release 1.3. Work currently being done, to derive better multipliers by including variations with latitude and/or Ls by comparison of MapYear 0 output directly against TES limb data, will be highlighted in the presentation. The TES limb data utilized in this process has been validated by a comparison study between Mars atmospheric density estimates from Mars-GRAM and measurements by Mars Global Surveyor (MGS). This comparison study was undertaken for locations on Mars of varying latitudes, Ls, and LTST. The more precise density factors will be included in Mars-GRAM 2005 Release 1.4 and thus improve the results of future sensitivity studies done for large

  12. Vibration performance comparison study on current fiber optic connector technologies

    NASA Astrophysics Data System (ADS)

    Thomes, William J., Jr.; LaRocca, Frank V.; Switzer, Robert C.; Ott, Melanie N.; Chuska, Richard F.; Macmurphy, Shawn L.

    2008-08-01

    Fiber optic cables are increasingly being used in harsh environments where they are subjected to vibration. Understanding the degradation in performance under these conditions is essential for integration of the fibers into the given application. System constraints often require fiber optic connectors so that subsystems can be removed or assembled as needed. In the present work, various types of fiber optic connectors were monitored in-situ during vibration testing to examine the transient change in optical transmission and the steady-state variation following the event. The fiber endfaces and connectors were inspected at selected intervals throughout the testing.

  13. Vibration Performance Comparison Study on Current Fiber Optic Connector Technologies

    NASA Technical Reports Server (NTRS)

    Ott, Melanie N.; Thomes Jr., William J.; LaRocca, Frank V.; Switzer, Robert C.; Chuska, Rick F.; Macmurphy, Shawn L.

    2008-01-01

    Fiber optic cables are increasingly being used in harsh environments where they are subjected to vibration. Understanding the degradation in performance under these conditions is essential for integration of the fibers into the given application. System constraints oftentimes require fiber optic connectors so subsystems can be removed or assembled as needed. In the present work, various types of fiber optic connectors were monitored in-situ during vibration testing to examine the transient change in optical transmission and the steady-state variation following the event. Inspection of the fiber endfaces and connectors was performed at chosen intervals throughout the testing.

  14. A Parametric Geometry Computational Fluid Dynamics (CFD) Study Utilizing Design of Experiments (DOE)

    NASA Technical Reports Server (NTRS)

    Rhew, Ray D.; Parker, Peter A.

    2007-01-01

    Design of Experiments (DOE) techniques were applied to the Launch Abort System (LAS) of the NASA Crew Exploration Vehicle (CEV) parametric geometry Computational Fluid Dynamics (CFD) study to efficiently identify and rank the primary contributors to the integrated drag over the vehicles ascent trajectory. Typical approaches to these types of activities involve developing all possible combinations of geometries changing one variable at a time, analyzing them with CFD, and predicting the main effects on an aerodynamic parameter, which in this application is integrated drag. The original plan for the LAS study team was to generate and analyze more than1000 geometry configurations to study 7 geometric parameters. By utilizing DOE techniques the number of geometries was strategically reduced to 84. In addition, critical information on interaction effects among the geometric factors were identified that would not have been possible with the traditional technique. Therefore, the study was performed in less time and provided more information on the geometric main effects and interactions impacting drag generated by the LAS. This paper discusses the methods utilized to develop the experimental design, execution, and data analysis.

  15. Cancer incidence among population utilizing geothermal hot water: a census-based cohort study.

    PubMed

    Kristbjornsdottir, Adalbjorg; Rafnsson, Vilhjalmur

    2013-12-15

    The aim of the study was to assess whether utilization of geothermal hot-water is associated with risk of cancer. The cohort from census was followed from 1981 to 2010 in nation-wide death and cancer registries. The moving apart of American-Eurasian tectonic plates, observed in Iceland, results in high volcanic activity. The definition of the study populations was based on geological information. The target population was inhabitants of communities located on bedrock younger than 3.3 million years, utilizing hot-water supply generated from geothermal wells since 1972. The two reference populations were inhabitants of communities without this hot-water supply located on areas with less volcanic/geothermal activity, and bedrock older than 3.3 million years. Hazard ratio (HR), and 95% confidence intervals (CI) were adjusted for age, gender, education, housing, reproductive factors and smoking. HR in the geothermal hot-water supply areas for all cancer was 1.15 (95% CI 1.05-1.25) as compared with nongeothermal areas. The HR for breast cancer was 1.40 (1.12-1.75), prostate cancer 1.61 (1.29-2.00), kidney cancer 1.64 (1.11-2.41), lymphatic and haematopoietic tissue cancers 1.45 (1.08-1.95), and for basal cell carcinoma (BCC) of the skin 1.46 (1.16-1.82). Positive exposure-response relations were observed between the risk of these cancers and the degree of volcanic/geothermal activity in the reference areas. Increased incidence of all cancers, breast, prostate, kidney cancer and BCC of the skin was found among the population utilizing geothermal hot-water for decades. More precise information on exposure is needed in future studies. PMID:23733434

  16. Structural adhesives for bonding optics to metals: a study of optomechanical stability

    NASA Astrophysics Data System (ADS)

    Daly, John G.; Daly, Damien J.

    2001-11-01

    With so many new adhesives available, characteristics affecting performance are not always well-defined. The user often selects an adhesive based on a single property and later finds his application compromised. This is an effort to study relevant properties of several different structural-type adhesives. The bonding geometry will utilize three types of glass bonded to metal mounts. The mounting geometry will include five different design approaches. These designs will investigate: face bonding, counter-bored mounts, edge bonding, and a flexure mount. The three metals selected are not only common to the industry but often used for matching the Coefficient of Expansion to the optical glass. Each optical flat will have its reflective surface used as a reference for angular stability. The adhesives selected will compare more traditional epoxies with one-part UV light cured products. The obvious advantage of the UV- cured adhesives is the instant cure on-demand. Several adhesives have been selected for differing properties including: viscosity, cure temperature, CTE, modulus of elasticity, out-gassing, and shrinkage upon cure. Discussion will compare each adhesive, its properties, and ease of use. Angular stability will be monitored as a function of: pre vs. post cure, accelerated life testing, thermal exposure, and vibration/shock exposure. Some discussion will be included on the wavefront distortion and stress birefringence.

  17. Studies of torsional properties of DNA and nucleosomes using angular optical trapping

    NASA Astrophysics Data System (ADS)

    Sheinin, Maxim Y.

    DNA in vivo is subjected to torsional stress due to the action of molecular motors and other DNA-binding proteins. Several decades of research have uncovered the fascinating diversity of DNA transformations under torsion and the important role they play in the regulation of vital cellular processes such as transcription and replication. Recent studies have also suggested that torsion can influence the structure and stability of nucleosomes---basic building blocks of the eukaryotic genome. However, our understanding of the impact of torsion is far from being complete due to significant experimental challenges. In this work we have used a powerful single-molecule experimental technique, angular optical trapping, to address several long-standing issues in the field of DNA and nucleosome mechanics. First, we utilized the high resolution and direct torque measuring capability of the angular optical trapping to precisely measure DNA twist-stretch coupling. Second, we characterized DNA melting under tension and torsion. We found that torsionally underwound DNA forms a left-handed structure, significantly more flexible compared to the regular B-DNA. Finally, we performed the first comprehensive investigation of the single nucleosome behavior under torque and force. Importantly, we discovered that positive torque causes significant dimer loss, which can have implications for transcription through chromatin.

  18. A rheo-optic study of hydrogen-bonded polymers

    SciTech Connect

    Van Buskirk, C.S.

    1988-01-01

    The influence of hydrogen bonds on polymer mechanical properties was examined using rheo-optic techniques. To isolate the hydrogen bond effect, poly(vinyl alcohol) (PVOH), which has a high hydrogen bond density, was studied during stress relaxation, a process dominated by intermolecular hydrogen bonds. To vary the degree and strength of hydrogen bonding, copolymers containing 2.7, 5.7, and 12.8% poly (vinyl acetate) were prepared by reacetylation of PVOH. Samples were also annealed. IR spectroscopy was used to measure samples' molecular response during stress relaxation. Samples were subjected to deuterium exchange reaction before testing, amorphous regions undergo this exchange process preferentially to crystalline regions. Because IR vibration is a function of mass, deuteration resulted in separation of crystalline and amorphous response to stress in the spectra: OH stretching frequency represented crystalline response, OD the amorphous. Prior to rheo-optic testing, polymers were characterized by differential scanning calorimetry. Analysis of these data lead to the identification of a previously improperly assigned endotherm near 410 K. Three types of stress relaxation tests were performed: high strain level, low strain level, and strain and recovery sequences. Correlations between stress and IR peak position and band distribution were found during the application of large strain, though during subsequent relaxation these correlations were not as pronounced. Results indicate that stress relaxation occurs by a redistribution of hydrogen bond strengths, and that stress is borne differently in crystalline and amorphous regions. Strain and recovery test results emphasized the correlation between stress and hydrogen bond strengths. These data indicated crystalline response to stress is stiff, whereas amorphous response is viscous.

  19. Calculus detection calibration among dental hygiene faculty members utilizing dental endoscopy: a pilot study.

    PubMed

    Partido, Brian B; Jones, Archie A; English, Dana L; Nguyen, Carol A; Jacks, Mary E

    2015-02-01

    Dental and dental hygiene faculty members often do not provide consistent instruction in the clinical environment, especially in tasks requiring clinical judgment. From previous efforts to calibrate faculty members in calculus detection using typodonts, researchers have suggested using human subjects and emerging technology to improve consistency in clinical instruction. The purpose of this pilot study was to determine if a dental endoscopy-assisted training program would improve intra- and interrater reliability of dental hygiene faculty members in calculus detection. Training included an ODU 11/12 explorer, typodonts, and dental endoscopy. A convenience sample of six participants was recruited from the dental hygiene faculty at a California community college, and a two-group randomized experimental design was utilized. Intra- and interrater reliability was measured before and after calibration training. Pretest and posttest Kappa averages of all participants were compared using repeated measures (split-plot) ANOVA to determine the effectiveness of the calibration training on intra- and interrater reliability. The results showed that both kinds of reliability significantly improved for all participants and the training group improved significantly in interrater reliability from pretest to posttest. Calibration training was beneficial to these dental hygiene faculty members, especially those beginning with less than full agreement. This study suggests that calculus detection calibration training utilizing dental endoscopy can effectively improve interrater reliability of dental and dental hygiene clinical educators. Future studies should include human subjects, involve more participants at multiple locations, and determine whether improved rater reliability can be sustained over time. PMID:25640616

  20. A second-law study on packed bed energy storage systems utilizing phase-change materials

    SciTech Connect

    Adebiyi, G.A. )

    1991-08-01

    Thermal modeling of packed bed, thermal energy storage systems has traditionally been limited to first-law considerations. The exceptions include a few second-law studies of sensible heat storage systems and the latent heat storage systems. The cited second-law studies treat the storage and removal processes essentially as batch heating and cooling. The approximation effectively ignores the significant temperature gradient, especially in the axial direction, in the storage medium over a substantial portion of both the storage and removal processes. The results presented in this paper are for a more comprehensive model of the packed bed storage system utilizing encapsulated phase-change materials. The fundamental equations for the system are similar to those of Schumann, except that a transient conduction equation is included for intraparticle conduction in each pellet. The equations are solved numerically, and the media temperatures obtained are used for the determination of the exergy (or availability) disposition in complete storage-removal cycles. One major conclusion of the study from both the first-law and second-law perspectives is that the principal advantage in the use of phase-change storage material is the enhanced storage capacity, compared with the same size of packed bed utilizing a sensible heat storage material. Thermodynamically, however, it does not appear that the system employing phase-change storage material will always, or necessarily, be superior to that using a sensible heat-storage material. The latter conclusion is reached only on the basis of the second-law evaluation.

  1. Transgenic mice expressing human glucocerebrosidase variants: utility for the study of Gaucher disease.

    PubMed

    Sanders, Angela; Hemmelgarn, Harmony; Melrose, Heather L; Hein, Leanne; Fuller, Maria; Clarke, Lorne A

    2013-08-01

    Gaucher disease is an autosomal recessively inherited storage disorder caused by deficiency of the lysosomal hydrolase, acid β-glucosidase. The disease manifestations seen in Gaucher patients are highly heterogeneous as is the responsiveness to therapy. The elucidation of the precise factors responsible for this heterogeneity has been challenging as the development of clinically relevant animal models of Gaucher disease has been problematic. Although numerous murine models for Gaucher disease have been described each has limitations in their specific utility. We describe here, transgenic murine models of Gaucher disease that will be particularly useful for the study of pharmacological chaperones. We have produced stable transgenic mouse strains that individually express wild type, N370S and L444P containing human acid β-glucosidase and show that each of these transgenic lines rescues the lethal phenotype characteristic of acid β-glucosidase null mice. Both the N370S and L444P transgenic models show early and progressive elevations of tissue sphingolipids with L444P mice developing progressive splenic Gaucher cell infiltration. We demonstrate the potential utility of these new transgenic models for the study of Gaucher disease pathogenesis. In addition, since these mice produce only human enzyme, they are particularly relevant for the study of pharmacological chaperones that are specifically targeted to human acid β-glucosidase and the common mutations underlying Gaucher disease. PMID:23642305

  2. Feasibility study on fiber-optic goniometer for measuring knee joint angle

    NASA Astrophysics Data System (ADS)

    Kim, Seon Geun; Jang, Kyoung Won; Yoo, Wook Jae; Shin, Sang Hun; Cho, Seunghyun; Lee, Bongsoo

    2014-09-01

    In this study, we fabricated a fiber-optic goniometer using a plastic optical fiber, a light-emitting diode, and a photodiode. The cladding of the plastic optical fiber was removed at 0.5-3mm intervals regularly to increase the bending loss of the plastic optical fiber. Also, the output voltages of the photodiode based on light intensity that measured using the fiber-optic goniometer were measured light intensities using the fiber-optic goniometer were measured to evaluate the linearity of the fiber-optic goniometer. Finally, we measured the responses of the fiber-optic goniometer for gait speeds of 3, 5, and 10 km/h using a data acquisition board and a LabVIEW program.

  3. Indentation device for in situ Raman spectroscopic and optical studies

    NASA Astrophysics Data System (ADS)

    Gerbig, Y. B.; Michaels, C. A.; Forster, A. M.; Hettenhouser, J. W.; Byrd, W. E.; Morris, D. J.; Cook, R. F.

    2012-12-01

    Instrumented indentation is a widely used technique to study the mechanical behavior of materials at small length scales. Mechanical tests of bulk materials, microscopic, and spectroscopic studies may be conducted to complement indentation and enable the determination of the kinetics and physics involved in the mechanical deformation of materials at the crystallographic and molecular level, e.g., strain build-up in crystal lattices, phase transformations, and changes in crystallinity or orientation. However, many of these phenomena occurring during indentation can only be observed in their entirety and analyzed in depth under in situ conditions. This paper describes the design, calibration, and operation of an indentation device that is coupled with a Raman microscope to conduct in situ spectroscopic and optical analysis of mechanically deformed regions of Raman-active, transparent bulk material, thin films or fibers under contact loading. The capabilities of the presented device are demonstrated by in situ studies of the indentation-induced phase transformations of Si thin films and modifications of molecular conformations in high density polyethylene films.

  4. Optical Studies of model binary miscibility gap system

    NASA Technical Reports Server (NTRS)

    Lacy, L. L.; Witherow, W. K.; Facemire, B. R.; Nishioka, G. M.

    1982-01-01

    In order to develop a better understanding of separation processes in binary miscibility gap metal alloys, model transparent fluid systems were studied. The system selected was diethylene glycol-ethyl salicylate which has convenient working temperatures (288 to 350 K), low toxicity, and is relatively easy to purify. The system is well characterized with respect to its phase diagram, density, surface and interfacial tensions, viscosity and other pertinent physical properties. Studies of migration of the dispersed phase in a thermal gradient were performed using conventional photomicroscopy. Velocities of the droplets of the dispersed phase were measured and compared to calculated rates which included both Stokes and thermal components. A holographic microscopy system was used to study growth, coalescence, and particle motions. Sequential holograms allowed determination of particle size distribution changes with respect to time and temperature. Holographic microscopy is capable of recording particle densities up to 10 to the 7th power particles/cu cm and is able to resolve particles of the order of 2 to 3 microns in diameter throughout the entire volume of the test cell. The reconstructed hologram produces a wavefront that is identical to the original wavefront as it existed when the hologram was made. The reconstructed wavefront is analyzed using a variety of conventional optical methods.

  5. Experimental study on optical fiber bundle hydrogen sensor based on palladium-silver optical thin film

    NASA Astrophysics Data System (ADS)

    Cui, Lu-jun; Shang, Hui-chao; Zhang, Gang; Li, Yong; Zhao, Ze-xiang

    2013-01-01

    In this paper, a 20 nm palladium-silver (Pd/Ag) ultrathin optical film is used for hydrogen gas sensing. The mole ratio of the two metals is controlled at Pd:Ag=3:1. In the direct current (DC) sputtering machine, the optical thin film is evaporated on the optical glass. Compared with pure palladium, the Pd/Ag alloy can increase the life and the stability of the sensing film. Optimum sputtering parameters for Pd/Ag alloy are presented in this paper, and the effects of different experimental conditions for hydrogen sensor are investigated, including the temperature effect, humidity effect and cross sensitivity of hydrogen sensor for different gases. The experiment results indicate that the hydrogen sensor based on Pd/Ag optical thin film exhibits good sensing characteristics. The existing of CO and water in hydrogen increases the response time and decreases the response amplitude of optical fiber bundle hydrogen sensor. The experiment results show that the increasing temperature can eliminate the effect and shorten hydrogen sensor response time effectively.

  6. Management of traumatic optic neuropathy--a study of 23 patients.

    PubMed Central

    Mauriello, J. A.; DeLuca, J.; Krieger, A.; Schulder, M.; Frohman, L.

    1992-01-01

    Twenty three patients with traumatic optic neuropathy were managed by medical and surgical treatment as follows. High dose intravenous steroids were initiated in all patients. If visions did not improve significantly after 24 to 48 hours decompression of an optic nerve sheath haematoma by medial orbitotomy and neurosurgical decompression of the optic canal were considered based on computed tomographic scan findings. Nine of 16 patients who received steroids only showed significant improvement. One of three showed improvement on optic nerve decompression after steroid failure; three or four showed improvement on optic nerve decompression after steroid failure; three or four showed improvement with combined optic nerve sheath decompression by the medial orbitotomy and decompression of the optic canal by frontal craniotomy. A lucid interval of vision after injury and an enlarged optic nerve sheath were associated with an improved prognosis. Five of the 23 patients had a lucid interval and all five had a final improved vision, while only five of 18 patients without a lucid interval improved. Similarly seven of the nine with an enlarged optic nerve sheath showed improvement while only three of 10 patients (three bilateral cases) who presented with no light perception improved with medical and surgical treatment. While a prospective controlled study of the management of traumatic optic neuropathy is necessary this preliminary study suggests that treatment of traumatic optic nerve sheath haematoma by optic nerve sheath decompression should be considered in selected patients. Images PMID:1622947

  7. Market study for direct utilization of geothermal resources by selected sectors of economy

    SciTech Connect

    Not Available

    1980-08-01

    A comprehensive analysis is presented of industrial markets potential for direct use of geothermal energy by a total of six industry sectors: food and kindred products; tobacco manufactures; textile mill products; lumber and wood products (except furniture); chemicals and allied products; and leather and leather products. A brief statement is presented regarding sectors of the economy and major manufacturing processes which can readily utilize direct geothermal energy. Previous studies on plant location determinants are summarized and appropriate empirical data provided on plant locations. Location determinants and potential for direct use of geothermal resources are presented. The data was gathered through interviews with 30 senior executives in the six sectors of economy selected for study. Probable locations of plants in geothermal resource areas and recommendations for geothermal resource marketing are presented. Appendix A presents factors which impact on industry location decisions. Appendix B presents industry executives interviewed during the course of this study. (MHR)

  8. Utilization of health services in Western Canada: basic Canadian data from the World Health Organization/International Collaborative Study of Medical Care Utilization.

    PubMed Central

    Matthews, V. L.; Feather, J.

    1976-01-01

    In a household health survey more than 15 000 individuals in four areas of Canada were interviewed as part of the World Health Organization/International Collaborative Study of Medical Care Utilization. Data were collected to describe the health services system in each area and to measure the population's utilization of health professionals, hospitals, medicines and selected preventive services, perceived acute and chronic morbidity, attitudes and beliefs about health and health care, and sociodemographic characteristics. The proportion of persons with perceived morbidity was twice that of persons reporting visits with a physician in the same 2-week period. Prescribed and nonprescribed medications had been used by more than 50% of respondents in each area in the 2 days before the interview, nonprescribed medicines accounting for more than half of this use. Respondents were found to be more sceptical of medical doctors than of medical science. PMID:1253067

  9. HIV patients in the HCUP database: a study of hospital utilization and costs.

    PubMed

    Hellinger, Fred J

    2004-01-01

    This study examines the utilization of hospital care by HIV patients in all hospitals in eight states (California, Colorado, Florida, Kansas, New Jersey, New York, Pennsylvania, and South Carolina), and examines the cost of hospital care for HIV patients in six of these states (California, Colorado, Kansas, New Jersey, New York, and South Carolina). The eight states in the sample account for more than 52% of all persons living with AIDS in the United States; the six states account for 39%. The unit of observation in both studies is a hospital admission by a patient with HIV. Hospital data were obtained from the Healthcare Cost and Utilization Project (HCUP), State Inpatient Database (SID), which is maintained by the Agency for Healthcare Research and Quality (AHRQ). The HCUP contains hospital discharge data and is a federal/state/industry partnership to build a multistate health care data system. Using multivariate analytic techniques and data from 2000, results indicate that cost and length of a hospital stay vary significantly across states after accounting for a patient's gender, insurance type, race, age, and number of diagnoses, as well as the teaching status and ownership category of the hospital. PMID:15224963

  10. ToHajiilee Economic Development, Inc.(TEDI) Feasibility Study for Utility-Scale Solar

    SciTech Connect

    Burpo, Rob

    2012-02-29

    To Hajiilee Economic Development, Inc. (TEDI) is the economic development entity representing the ToHajiilee Chapter of the Navajo Nation, also known as the Caoncito Band of Navajo (CBN). Using DOE funding, TEDI assembled a team of qualified advisors to conduct a feasibility study for a utility-scale 30 MW Photovoltaic (PV) solar power generation facility on TEDI trust lands. The goal for this project has been to gather information and practical business commitments to successfully complete the feasibility analysis. The TEDI approach was to successively make informed decisions to select an appropriate technology best suited to the site, determine environmental viability of the site, secure options for the sale of generated power, determine practicality of transmission and interconnection of power to the local grid, and secure preliminary commitments on project financing. The feasibility study has been completed and provides TEDI with a practical understanding of its business options in moving forward with developing a solar project on CBN tribal lands. Funding from DOE has allowed TEDI and its team of professional advisors to carefully select technology and business partners and build a business model to develop this utility-scale solar project. As a result of the positive feasibility findings, TEDI is moving forward with finalizing all pre-construction activities for its major renewable energy project.

  11. Transmission of Duobinary Signal in Optical 40 GHz Millimeter-Wave Radio-Over-Fiber Systems Utilizing Dual-Arm LiNbO3 Mach-Zehnder Modulator for Downstream

    NASA Astrophysics Data System (ADS)

    Dong-Nhat, Nguyen; Malekmohammadi, Amin

    2016-06-01

    In this paper, for the first time transmission of 2.5 Gb/s duobinary signal is investigated for the downlink direction in 40 GHz optical millimeter-wave generation or up-conversion, utilizing a dual-arm LiNb{O}_3 Mach-Zehnder modulator based on different modulation schemes, namely double- and single-sideband (DSB and SSB) and optical carrier suppression (OCS). The up-converted optical millimeter-wave employing OCS modulation scheme indicates the highest back-to-back received optical power and the smallest power penalty after long propagation in the single-mode fiber, in comparison to DSB and SSB. Directly modulated laser in association with OCS modulation scheme has been used to generate duobinary optical millimeter-wave signal in order to minimize the cost and complexity of the system.

  12. Errors and optics study of a permanent magnet quadrupole system

    NASA Astrophysics Data System (ADS)

    Schillaci, F.; Maggiore, M.; Rifuggiato, D.; Cirrone, G. A. P.; Cuttone, G.; Giove, D.

    2015-05-01

    Laser-based accelerators are gaining interest in recent years as an alternative to conventional machines [1]. Nowadays, energy and angular spread of the laser-driven beams are the main issues in application and different solutions for dedicated beam-transport lines have been proposed [2,3]. In this context a system of permanent magnet quadrupoles (PMQs) is going to be realized by INFN [2] researchers, in collaboration with SIGMAPHI [3] company in France, to be used as a collection and pre-selection system for laser driven proton beams. The definition of well specified characteristics, both in terms of performances and field quality, of the magnetic lenses is crucial for the system realization, for an accurate study of the beam dynamics and the proper matching with a magnetic selection system already realized [6,7]. Hence, different series of simulations have been used for studying the PMQs harmonic contents and stating the mechanical and magnetic tolerances in order to have reasonable good beam quality downstream the system. In this paper is reported the method used for the analysis of the PMQs errors and its validation. Also a preliminary optics characterization is presented in which are compared the effects of an ideal PMQs system with a perturbed system on a monochromatic proton beams.

  13. Geometric-optical studies for metamaterial representations of curved spacetime

    NASA Astrophysics Data System (ADS)

    Anderson, Tom H.; Mackay, Tom G.; Lakhtakia, Akhlesh

    2011-10-01

    Metamaterials offer opportunities to explore curved-spacetime scenarios which would otherwise be impractical or impossible to study. These opportunities arise from the formal analogy that exists between light propagation in vacuous curved spacetime and in a certain nonhomogeneous bianisotropic medium, called a Tamm medium. As the science and technology of nanostructured metamaterials continues its rapid development, the practical realization of Tamm mediums is edging ever closer. We considered two particular curved spacetimes associated with: (a) spinning cosmic strings, and (b) the Alcubierre drive. For both examples, a Tamm medium formulation was developed which is asymptotically identical to vacuum and is therefore amenable to physical realization. A study of ray trajectories for both Tamm mediums was undertaken, within the geometric optics regime. For the spinning cosmic string, it was observed that: (i) rays do not cross the string's boundary; (ii) evanescent waves are supported in regions of phase space that correspond to those regions of the string's spacetime wherein closed timelike curves may arise; and (iii) a non-spinning string is nearly invisible whereas a spinning string may be rather more visible. For the Alcubierre drive, it was observed that: (i) ray trajectories are highly sensitive to the magnitude and direction of the warp bubble's velocity, but less sensitive to the thickness of the transition zone between the warp bubble and its background; and (ii) the warp bubble acts as a focusing lens for rays which travel in the same direction as the bubble, especially at high speeds.

  14. Study on test metrology of large aperture optical system wavefront

    NASA Astrophysics Data System (ADS)

    Liu, Zhiying; Fu, Yuegang; Gao, Tianyuan; Wang, Zhijian

    2009-05-01

    Large aperture optical system test has been a key problem for a long time. It could be solved by sub-aperture stitching method after the sub-apertures are tested. Sub-aperture stitching technology is a feasible method for testing large diameter optical system with small diameter interferometer sub-aperture stitching. Auto-collimating component will be needed with interferometer stitching method. Auto-collimating component is defined that the image could be kept stable when the optical component rotates about any axis in space. And the beam could be back along original optical path. By this means, auto collimation could be realized. The auto-collimating component is smaller than the test system. The whole wavefront of large aperture system could be tested through the method that the auto-collimating component moves along the guide rail and rotates about optical axis. A right angle roof prism is chosen as the auto-collimating component due to its character of easier manufacture. The active matrix, characteristic orientation and extreme axial is deduced with dynamic optics. The sub-aperture stitching testing process is simulated by ZEMAX in detail. The test result by stitching method is compared with that by directive test method for large aperture optical system. It is shown that the relative test error is less than 4.3λ 0/00. The sub -aperture stitching test method is verified.

  15. Earned Income Credit Utilization by Welfare Recipients: A Case Study of Minnesota's Earned Income Credit Program

    ERIC Educational Resources Information Center

    Hirasuna, Donald P.; Stinson, Thomas F.

    2007-01-01

    This paper examines utilization of a state earned income credit by AFDC and TANF recipients. Although utilization percentages are increasing, we find that among TANF recipients in 1999, 45.7 percent of all households and 34.8 percent of eligible households did not receive the state earned income credit. Moreover, we find that utilization may…

  16. Subterranean Carbon Dioxide Concentration Analysis Utilizing a Scalable Optical Fiber-Based Absorption Cell Array for Carbon Capture and Storage Site Integrity Monitoring

    NASA Astrophysics Data System (ADS)

    Wicks, G. R.; Soukup, B.; Repasky, K. S.; Carlsten, J.

    2011-12-01

    Geologic carbon sequestration is a means to mitigate the increasing atmospheric concentration of carbon dioxide (CO2) by capturing the CO2 at a source such as a power generation facility and storing the captured CO2 in geologic formations. Many technological advances will need to occur for successful carbon sequestration, including near surface monitoring tools and techniques to ensure site integrity and public safety. Researchers at Montana State University (MSU) are developing a scalable fiber sensor array in a call/return configuration for monitoring near sub-surface CO2 concentrations for the purpose of carbon sequestration site integrity monitoring. The system measures CO2 concentrations through the application of tunable diode laser absorption spectroscopy (TDLAS). The instrument utilizes four fiber probes (absorption cells) connected to a detector, a fiber-optic beam splitter, and a 1 x 4 fiber-optic micro-electromechanical (MEMS) switch that can direct the light to one of the four probes, and employs a single tunable distributed feedback (DFB) diode laser with a center wavelength of 2.004 μm to access CO2 absorption features. The fiber sensor array can easily be reconfigured by simply moving the fiber probes. Low cost is achieved by using inexpensive passive components in the probes while limiting the number of the more expensive components including the DFB laser, the detector, and the 1 X 4 MEMS switch. The fiber sensor system was tested over a sixty day period centered on a thirty day controlled CO2 release at the Zero Emission Research Technology (ZERT) facility that was developed for sub-surface and near surface carbon sequestration monitoring research. In this presentation, the design of the fiber sensor array system will be presented, along with the system performance during the sixty day monitoring experiment.

  17. Preliminary study on weapon grade uranium utilization in molten salt reactor miniFUJI

    SciTech Connect

    Aji, Indarta Kuncoro; Waris, A.

    2014-09-30

    Preliminary study on weapon grade uranium utilization in 25MWth and 50MWth of miniFUJI MSR (molten salt reactor) has been carried out. In this study, a very high enriched uranium that we called weapon grade uranium has been employed in UF{sub 4} composition. The {sup 235}U enrichment is 90 - 95 %. The results show that the 25MWth miniFUJI MSR can get its criticality condition for 1.56 %, 1.76%, and 1.96% of UF{sub 4} with {sup 235}U enrichment of at least 93%, 90%, and 90%, respectively. In contrast, the 50 MWth miniFUJI reactor can be critical for 1.96% of UF{sub 4} with {sup 235}U enrichment of at smallest amount 95%. The neutron spectra are almost similar for each power output.

  18. Evaluation of utility of pharmacokinetic studies in phase I trials of two oncology drugs

    PubMed Central

    Wu, Kehua; House, Larry; Ramírez, Jacqueline; Seminerio, Michael J.; Ratain, Mark J.

    2013-01-01

    Purpose There are many phase I trials of oncology drug combinations, very few of which report clinically significant pharmacokinetic interactions. We hypothesized that the utility of such pharmacokinetic drug-drug interaction (DDI) studies is low in the absence of a mechanistic hypothesis. Experimental Design We retrospectively reviewed 152 phase I (2 drug) combination studies published in 2007–2011. Results Only 28 (18%) studies had an implicit or explicit rationale, either inhibition/induction of a drug metabolizing enzyme or transporter, co-substrates for the same enzyme or transporter, potential for end-organ toxicity, or protein binding. Only 12 (8%) studies demonstrated a statistically significant DDI, based on change in clearance (or area under the curve) of parent drug and/or active metabolite. There was a strong association between a rationale and a demonstrable drug interaction, as only 2% of studies without a rationale demonstrated a DDI, compared to 32% of studies with a rationale (Fisher’s exact test, p<10−6). Conclusion DDI studies should not be routinely performed as part of phase I trials of oncology combinations. PMID:24056785

  19. Workplace Harassment Patterning, Gender, and Utilization of Professional Services: Findings from a US National Study

    PubMed Central

    Shannon, Candice A.; Rospenda, Kathleen M.; Richman, Judith A.

    2007-01-01

    This study constitutes the first national longitudinal survey to address the relationship between workplace harassment and service utilization. We examine how patterns of sexual harassment and generalized workplace harassment are linked to utilization of mental health, health, legal, spiritual, and work-related services, and whether and how gender influences these relationships. Data derive from a random digit dial telephone survey with a continental U.S. sample of employed adults. Eligibility criteria were being 18 years of age or over, and being employed at least 20 hours per week at some time in the 12 months prior to the wave 1 survey. Out of 4,116 households with eligible individuals, 2,151 agreed to participate at wave 1. 1,418 participated at wave 2, thus, the overall response rate was 34.5%. We show that the patterning of workplace harassment over two time points (chronic, remission, onset, never harassed) is associated with the use of different types of services. Gender partially moderated the relationship between workplace harassment and services. PMID:17166642

  20. Health utilities of type 2 diabetes-related complications: a cross-sectional study in Sweden.

    PubMed

    Kiadaliri, Aliasghar A; Gerdtham, Ulf-G; Eliasson, Björn; Gudbjörnsdottir, Soffia; Svensson, Ann-Marie; Carlsson, Katarina Steen

    2014-05-01

    This study estimates health utilities (HU) in Sweden for a range of type 2 diabetes-related complications using EQ-5D and two alternative tariffs (UK and Swedish) from 1757 patients with type 2 diabetes from the Swedish National Diabetes Register (NDR). Ordinary least squares were used for statistical analysis. Lower HU was found for female gender, younger age at diagnosis, higher BMI, and history of complications. Microvascular and macrovascular complications had the most negative effect on HU among women and men, respectively. The greatest decline in HU was associated with kidney disorders (-0.114) using the UK tariff and stroke (-0.059) using the Swedish tariff. Multiple stroke and non-acute ischaemic heart disease had higher negative effect than a single event. With the UK tariff, each year elapsed since the last microvascular/macrovascular complication was associated with 0.013 and 0.007 units higher HU, respectively. We found important heterogeneities in effects of complications on HU in terms of gender, multiple event, and time. The Swedish tariff gave smaller estimates and so may result in less cost-effective interventions than the UK tariff. These results suggest that incorporating subgroup-specific HU in cost-utility analyses might provide more insight for informed decision-making. PMID:24810579

  1. The use and utility of specific nonpharmacological interventions for behavioral symptoms in dementia: an exploratory study

    PubMed Central

    Cohen-Mansfield, Jiska; Marx, Marcia S.; Dakheel-Ali, Maha; Thein, Khin

    2014-01-01

    OBJECTIVE This study compares different non-pharmacological interventions for persons with behavioral symptoms and dementia on frequency of use and perceived efficacy in terms of change in behavior and interest. METHODS Participants were 89 nursing home residents from 6 Maryland nursing homes with a mean age of 85.9 years (SD=8.6). Research assistants presented interventions tailored to the participants` needs and preferences in a pre-intervention trial phase and in an intervention phase. The impact of each intervention on behavioral symptoms and on the person’s interest was rated immediately after the intervention by a research assistant. RESULTS The most utilized interventions in both trial and treatment phases were the social intervention of one-on-one interaction, simulated social interventions such as a lifelike doll and respite video, the theme intervention of magazine, and the sensory stimulation intervention of music. In contrast, the least utilized interventions in both phases were sewing, fabric book, and flower arrangement. Interventions with the highest impact on behavioral symptoms included one-on one social interaction, hand massage, music, video, care, and folding towels. Other high impact interventions included walking, going outside, flower arranging, food or drink, sewing, group activity, book presentation ball toss, coloring or painting, walking, and family video. CONCLUSIONS The results provide initial directions for choosing specific interventions for persons with dementia and also demonstrate a methodology for increasing knowledge through ongoing monitoring of practice. PMID:25081819

  2. A Survey of Bandwidth Utilization: Case Study of Federal University of Technology Minna

    NASA Astrophysics Data System (ADS)

    Haq, A.; Bello Salau, H.; Aibinu, A. M.; Onwuka, E. N.

    2013-12-01

    The effective utilization of the limited scarce bandwidth resources allocated by a spectrum regulator usually the Nigerian Communications Commissions (NCC) in Nigeria universities is paramount in maximizing the usage of the expensive scarce bandwidth resources. A significant bandwidth allocation is needed in order to meet up with the challenges of the day and the task of networking, communicating and reaching the word in our universities. Therefore, bandwidth management becomes necessary and essential. This paper contributes in that direction by surveying the bandwidth utilization at Federal University of Technology Minna campus with the hope of proffering a general solution that can be adopted in Nigerian universities for effective bandwidth management. Also, factors that hindered the development of most Nigeria universities are also examined. The federal university of technology minna which is structured like all other universities in the country in terms of the bandwidth requirement was choosing as a case study for this research work. Furthermore, some policies which can be adopted in order to effectively manage the scarce bandwidth resources in Nigerian universities are also proposed.

  3. A study of optically contacted quartz at cryogenic temperatures

    NASA Technical Reports Server (NTRS)

    Payne, L. L.

    1982-01-01

    Optical contacting as a method of joining the quartz components of the instruments for the Gravity Probe-B experiment is evaluated. The strength of the bond between optically contacted fused quartz surfaces at liquid helium temperature was investigated. A test apparatus which can be used for making measurements of the tensile strength of these bonds was designed. Results of the tensile pull tests are given and the reliability of such bonds analyzed.

  4. Optical intraday variability studies of 10 low energy peaked blazars

    NASA Astrophysics Data System (ADS)

    Rani, Bindu; Gupta, Alok C.; Joshi, U. C.; Ganesh, S.; Wiita, Paul J.

    2011-05-01

    We have carried out optical (R band) intraday variability (IDV) monitoring of a sample of 10 bright low energy peaked blazars (LBLs). 40 photometric observations, of an average of ˜4 h each, were made between 2008 September and 2009 June using two telescopes in India. Measurements with good signal-to-noise ratios were typically obtained within 1-3 min, allowing the detection of weak, fast variations using N-star differential photometry. We employed both structure function and discrete correlation function analysis methods to estimate any dominant time-scales of variability and found that in most of the cases any such time-scales were longer than the duration of the observation. The calculated duty cycle of IDV in LBLs during our observing run is ˜52 per cent, which is low compared to many earlier studies; however, the relatively short periods for which each source was observed can probably explain this difference. We briefly discuss possible emission mechanisms for the observed variability.

  5. Study of the optical phonons on gated twisted bilayer graphene

    NASA Astrophysics Data System (ADS)

    Chung, Ting Fung; He, Rui; Wu, Tai-Lung; Chen, Yong P.

    2015-03-01

    In twisted bilayer graphene (tBLG), the low-energy van-Hove singularities (vHs) in the density of states (DOS) can be continuously tuned by twisting the two layers, leading to distinct electronic and optical properties compared to Bernal-stacked BLG (AB-BLG). This effect has been explored using resonance Raman scattering, showing enhanced Raman G and ZO' (low frequency, layer breathing vibration) bands when the vHs energy resonates with excitation laser energy. We have studied the influence on vHs and Raman bands in gated tBLG devices (at resonant twist angle ~13° under a 532 nm laser light). We observed that the G band splits with increasing doping, attributed to asymmetric doping of charge carriers in the two layers. The strongly quenched G band intensity at high doping level is ascribed to the suppression of resonant interband transitions between the two saddle points (in conduction and valence bands) which are displaced in the momentum space by gate-tuning. We have also measured the doping dependence of ZO' band and R band in tBLG. Our results demonstrate that electric-field can be used to tune the optoelectronic and vibrational properties in tBLG devices.

  6. Fundamental limits of optical critical dimension metrology: a simulation study

    NASA Astrophysics Data System (ADS)

    Silver, Richard; Germer, Thomas; Attota, Ravikiran; Barnes, Bryan M.; Bunday, Benjamin; Allgair, John; Marx, Egon; Jun, Jay

    2007-03-01

    This paper is a comprehensive summary and analysis of a SEMATECH funded project to study the limits of optical critical dimension scatterometry (OCD). The project was focused on two primary elements: 1) the comparison, stability, and validity of industry models and 2) a comprehensive analysis of process stacks to evaluate the ultimate sensitivity and limits of OCD. Modeling methods are a requirement for the interpretation and quantitative analysis of scatterometry data. The four models evaluated show good agreement over a range of targets and geometries for zero order specular reflection as well as higher order diffraction. A number of process stacks and geometries representing semiconductor manufacturing nodes from the 45 nm node to the 18 nm node were simulated using several measurement modalities including angle-resolved scatterometry and spectrally-resolved scatterometry, measuring various combinations of intensity and polarization. It is apparent in the results that large differences are observed between those methods that rely upon unpolarized and single polarization measurements. Using the three parameter fits and assuming that the sensitivity of scatterometry must meet the criterion that the 3σ uncertainty in the bottom dimension must be less than 2% of the linewidth, specular scatterometry solutions exist for all but the isolated lines at 18 nm node. Scatterometry does not have sufficient sensitivity for isolated and semi-isolated lines at the 18 nm node unless the measurement uses wavelengths as short as 200 nm or 150 nm and scans over large angle ranges.

  7. Epidemiology and Medication Utilization Pattern of Aortic Dissection in Taiwan: A Population-Based Study.

    PubMed

    Yeh, Ting-Yu; Chen, Chung-Yu; Huang, Jiann-Woei; Chiu, Chaw-Chi; Lai, Wen-Ter; Huang, Yaw-Bin

    2015-09-01

    Acute aortic dissection (AD) is a catastrophic condition associated with a high rate of mortality. However, current epidemiological information regarding AD remains sparse. The objective of the present study was to investigate the current epidemiological profile and medication utilization patterns associated with aortic dissection in Taiwan.In this population-based study, we identified cases of AD diagnosed during 2005 to 2012 in the complete Taiwan National Health Insurance (NHI) Research Database. Patients with AD were identified using the International Classification of Disease, Ninth Revision (ICD-9) code 441.0, and surgical interventions were defined using NHI procedure codes.A total of 9092 individuals with a mean age of 64.4 ± 15.1 years were identified. The cases were divided into 3 groups: Group A included 2340 patients (25.74%) treated surgically for type A AD; Group B included 1144 patients (12.58%) treated surgically for type B AD, and Group C included 5608 patients (61.68%) with any type of AD treated with medical therapy only. The average annual incidence of AD was 5.6 per 100,000 persons, and the average prevalence was 19.9 per 100,000 persons. Hypertension was the most common risk factor, followed by coronary artery disease and chronic obstructive pulmonary disease. Within 1 year of AD diagnosis, 92% of patients were taking antihypertensive medication. Calcium channel blockers were the most frequently prescribed antihypertensive medication for long-term observation in Taiwan.The annual trends revealed statistically significant increases in the numbers and percentages of prevalence, incidence, and mortality. Changes in patients' drug utilization in patterns were observed after AD diagnosis. Our study provides a local profile that supports further in-depth analyses in AD-affected populations. PMID:26356726

  8. Electronic and optical properties of nanocrystalline WO₃ thin films studied by optical spectroscopy and density functional calculations.

    PubMed

    Johansson, Malin B; Baldissera, Gustavo; Valyukh, Iryna; Persson, Clas; Arwin, Hans; Niklasson, Gunnar A; Osterlund, Lars

    2013-05-22

    The optical and electronic properties of nanocrystalline WO3 thin films prepared by reactive dc magnetron sputtering at different total pressures (Ptot) were studied by optical spectroscopy and density functional theory (DFT) calculations. Monoclinic films prepared at low Ptot show absorption in the near infrared due to polarons, which is attributed to a strained film structure. Analysis of the optical data yields band-gap energies Eg ≈ 3.1 eV, which increase with increasing Ptot by 0.1 eV, and correlate with the structural modifications of the films. The electronic structures of triclinic δ-WO3, and monoclinic γ- and ε-WO3 were calculated using the Green function with screened Coulomb interaction (GW approach), and the local density approximation. The δ-WO3 and γ-WO3 phases are found to have very similar electronic properties, with weak dispersion of the valence and conduction bands, consistent with a direct band-gap. Analysis of the joint density of states shows that the optical absorption around the band edge is composed of contributions from forbidden transitions (>3 eV) and allowed transitions (>3.8 eV). The calculations show that Eg in ε-WO3 is higher than in the δ-WO3 and γ-WO3 phases, which provides an explanation for the Ptot dependence of the optical data. PMID:23614973

  9. Optical and magneto-optical studies of martensitic transformation in Ni-Mn-Ga magnetic shape memory alloys

    SciTech Connect

    Beran, L.; Cejpek, P.; Kulda, M.; Antos, R.; Holy, V.; Veis, M.; Straka, L.; Heczko, O.

    2015-05-07

    Optical and magneto-optical properties of single crystal of Ni{sub 50.1}Mn{sub 28.4}Ga{sub 21.5} magnetic shape memory alloy during its transformation from martensite to austenite phase were systematically studied. Crystal orientation was approximately along (100) planes of parent cubic austenite. X-ray reciprocal mapping confirmed modulated 10 M martensite phase. Temperature depended measurements of saturation magnetization revealed the martensitic transformation at 335 K during heating. Magneto-optical spectroscopy and spectroscopic ellipsometry were measured in the sample temperature range from 297 to 373 K and photon energy range from 1.2 to 6.5 eV. Magneto-optical spectra of polar Kerr rotation as well as the spectra of ellipsometric parameter Ψ exhibited significant changes when crossing the transformation temperature. These changes were assigned to different optical properties of Ni-Mn-Ga in martensite and austenite phases due to modification of electronic structure near the Fermi energy during martensitic transformation.

  10. Optical and magneto-optical studies of martensitic transformation in Ni-Mn-Ga magnetic shape memory alloys

    NASA Astrophysics Data System (ADS)

    Beran, L.; Cejpek, P.; Kulda, M.; Antos, R.; Holy, V.; Veis, M.; Straka, L.; Heczko, O.

    2015-05-01

    Optical and magneto-optical properties of single crystal of Ni50.1Mn28.4Ga21.5 magnetic shape memory alloy during its transformation from martensite to austenite phase were systematically studied. Crystal orientation was approximately along {100} planes of parent cubic austenite. X-ray reciprocal mapping confirmed modulated 10 M martensite phase. Temperature depended measurements of saturation magnetization revealed the martensitic transformation at 335 K during heating. Magneto-optical spectroscopy and spectroscopic ellipsometry were measured in the sample temperature range from 297 to 373 K and photon energy range from 1.2 to 6.5 eV. Magneto-optical spectra of polar Kerr rotation as well as the spectra of ellipsometric parameter Ψ exhibited significant changes when crossing the transformation temperature. These changes were assigned to different optical properties of Ni-Mn-Ga in martensite and austenite phases due to modification of electronic structure near the Fermi energy during martensitic transformation.

  11. Optical and Magneto-Optical Studies of Doped III -v Quantum Well Structures.

    NASA Astrophysics Data System (ADS)

    Fisher, Tracey Ann

    1992-01-01

    The main theme of this thesis is the optical study of strained semiconductor structures. This includes using photo-luminescence (PL) and photo-luminescence excitation (PLE), both with and without a magnetic field. The principal structures employed are a series of asymmetric modulation doped rm Al_{x}Ga_ {1-x}As-rm In_{y }Ga_{1-y}As-GaAs quantum wells (AMDQWs) in which a high density of electrons occupies up to two subbands (n = 1,2) in the strained In _{rm y}{Ga}_ {rm 1-y}As quantum well. Several interesting phenomena due principally to the high-electron density, are discussed (supported by self-consistent calculations). The first experimental evidence is reported for the indirect fundamental bandgap (in wave-vector space), developed when a magnetic field is applied parallel to the plane of the layers. The PL undergoes a large approximately quadratic shift. This is a consequence of the allowed transitions in an increasingly indirect gap band structure. Of particular interest is the Fermi Energy Edge Singularity (FEES) observed in AMDQWs with significant occupation of the second subband (n = 2). The FEES is a many body effect observed in PL and PLE as an excitonic enhancement near the Fermi energy (E_{rm F}). From the characteristic temperature dependent broadening and decrease of PLE peak height in a Schottky gated AMDQW, a minimum electron density in n = 2 of 0.4 x 10 ^{11} cm^{ -2} is established for the clear observation of FEES behaviour. In samples where E_ {rm F} is close to the subband separation E_2-E_1 magneto -oscillations in the PL intensity of E_2 , are observed; E_{21} is attributed to hybridisation of n = 1 electrons near E_{rm F}, with n = 2 states. It is shown that the E_{21 } oscillations can be accounted for in terms of oscillations in the occupation of n = 1 Landau level states near E_2. Other phenomena discussed include Resonant Polaron Coupling between occupied LLs and LO phonons. PL results are presented for a Double Barrier Resonant

  12. Study of Collective Effects for the PEP Low-Emittance Optics

    SciTech Connect

    Zisman, M.S.; Borland, M.; Galayda, J.; Jackson, A.; Kramer, S.; Winick, H.

    1988-07-01

    Experimental studies have been performed on the PEP storage ring run at 7.1 GeV in the low-emittance mode. The motivation for this work is to explore the capability of PEP as a dedicated synchrotron radiation source. The long straight sections and low emittance available at PEP make its use for this purpose very attractive, and would produce a source of very high brightness x-ray beams for the scientific community. During the studies, single-bunch current limitations were measured as a function of RF voltage. Thresholds were in the range of 1-2 mA per bunch, which is lower than expected based upon transverse impedance estimates from the PEP collider optics. An increase in threshold current by about 50% was realized by modifying the optics to reduce the magnitude of the horizontal beta functions in the straight sections and at the RF locations. The reason for the lower than expected thresholds has not been resolved. To permit its effective use as a synchrotron radiation source, a beam current of 50-100 mA is desired, which will require that PEP be run in the multibunch mode. Our goal in this study was to investigate the multibunch operating mode to ascertain that reasonable beam intensities were possible. By utilizing many low intensity (0.1-0.25 mA) bunches, stable and reproducible currents of 15-20 mA were achieved. In an attempt to improve this value, one of the idle RF stations was operated in a tune-splitting mode, with only partial success. By adjusting the tuner positions of the unused RF stations, up to 33 mA was ultimately stored, albeit with some evidence for instability. Possible approaches to improving the multibunch stability are discussed.

  13. The development of optical microscopy techniques for the advancement of single-particle studies

    NASA Astrophysics Data System (ADS)

    Marchuk, Kyle

    Single particle orientation and rotational tracking (SPORT) has recently become a powerful optical microscopy tool that can expose many molecular motions. Unfortunately, there is not yet a single microscopy technique that can decipher all particle motions in all environmental conditions, thus there are limitations to current technologies. Within, the two powerful microscopy tools of total internal reflection and interferometry are advanced to determine the position, orientation, and optical properties of metallic nanoparticles in a variety of environments. Total internal reflection is an optical phenomenon that has been applied to microscopy to produce either fluorescent or scattered light. The non-invasive far-field imaging technique is coupled with a near-field illumination scheme that allows for better axial resolution than confocal microscopy and epi-fluorescence microscopy. By controlling the incident illumination angle using total internal reflection fluorescence (TIRF) microscopy, a new type of imaging probe called "non-blinking" quantum dots (NBQDs) were super-localized in the axial direction to sub-10-nm precision. These particles were also used to study the rotational motion of microtubules being propelled by the motor protein kinesin across the substrate surface. The same instrument was modified to function under total internal reflection scattering (TIRS) microscopy to study metallic anisotropic nanoparticles and their dynamic interactions with synthetic lipid bilayers. Utilizing two illumination lasers with opposite polarization directions at wavelengths corresponding to the short and long axis surface plasmon resonance (SPR) of the nanoparticles, both the in-plane and out-of-plane movements of many particles could be tracked simultaneously. When combined with Gaussian point spread function (PSF) fitting for particle super-localization, the binding status and rotational movement could be resolved without degeneracy. TIRS microscopy was also used to

  14. The development of optical microscopy techniques for the advancement of single-particle studies

    SciTech Connect

    Marchuk, Kyle

    2013-05-15

    Single particle orientation and rotational tracking (SPORT) has recently become a powerful optical microscopy tool that can expose many molecular motions. Unfortunately, there is not yet a single microscopy technique that can decipher all particle motions in all environmental conditions, thus there are limitations to current technologies. Within, the two powerful microscopy tools of total internal reflection and interferometry are advanced to determine the position, orientation, and optical properties of metallic nanoparticles in a variety of environments. Total internal reflection is an optical phenomenon that has been applied to microscopy to produce either fluorescent or scattered light. The non-invasive far-field imaging technique is coupled with a near-field illumination scheme that allows for better axial resolution than confocal microscopy and epi-fluorescence microscopy. By controlling the incident illumination angle using total internal reflection fluorescence (TIRF) microscopy, a new type of imaging probe called “non-blinking” quantum dots (NBQDs) were super-localized in the axial direction to sub-10-nm precision. These particles were also used to study the rotational motion of microtubules being propelled by the motor protein kinesin across the substrate surface. The same instrument was modified to function under total internal reflection scattering (TIRS) microscopy to study metallic anisotropic nanoparticles and their dynamic interactions with synthetic lipid bilayers. Utilizing two illumination lasers with opposite polarization directions at wavelengths corresponding to the short and long axis surface plasmon resonance (SPR) of the nanoparticles, both the in-plane and out-of-plane movements of many particles could be tracked simultaneously. When combined with Gaussian point spread function (PSF) fitting for particle super-localization, the binding status and rotational movement could be resolved without degeneracy. TIRS microscopy was also used to

  15. The Urban Ecology Institute's field studies program: utilizing urban areas for experiential learning and ecological research

    NASA Astrophysics Data System (ADS)

    Starry, O.

    2005-05-01

    The Urban Ecology Institute (UEI) promotes the stewardship of healthy urban ecosystems by improving science and civic education for middle and high school youth and by working with urban communities to protect and transform natural resources. Established in 1999, UEI's field studies program engages over 1000 youth in the greater Boston area. A substantial component of this program involves water quality monitoring. We have recently adapted protocols from published leaf breakdown studies for incorporation into the UEI water quality curriculum. A 2004 pilot study of these leaf breakdown activities, conducted at four sites, compared rates of red maple breakdown to those of Norway maple, a potentially invasive urban street tree. Preliminary data from this successful pilot study suggest that leaf litter inputs from the two different tree species have varying effects on stream ecosystem function. We present this study as an example of how urban areas can be utilized for both ecological research and inclusive experiential learning through which science and mathematic knowledge can be effectively communicated.

  16. Space processing applications payload equipment study. Volume 2E: Commercial equipment utility

    NASA Technical Reports Server (NTRS)

    Smith, A. G. (Editor)

    1974-01-01

    Examination of commercial equipment technologies revealed that the functional performance requirements of space processing equipment could generally be met by state-of-the-art design practices. Thus, an apparatus could be evolved from a standard item or derived by custom design using present technologies. About 15 percent of the equipment needed has no analogous commercial base of derivation and requires special development. This equipment is involved primarily with contactless heating and position control. The derivation of payloads using commercial equipment sources provides a broad and potentially cost-effective base upon which to draw. The derivation of payload equipment from commercial technologies poses other issues beyond that of the identifiable functional performance, but preliminary results on testing of selected equipment testing appear quite favorable. During this phase of the SPA study, several aspects of commercial equipment utility were assessed and considered. These included safety, packaging and structural, power conditioning (electrical/electronic), thermal and materials of construction.

  17. Utilization potential of coal combustion by-products: Somerset Power Plant case study: Final report

    SciTech Connect

    Baker, M. Jr.

    1987-01-01

    This report provides analyses of the potential for the sale of ash and ash-derived products for twelve distinct applications in western New York State and the Toronto metropolitan area. Some unique features of this study include the distribution of a questionnaire directed at potential by-product purchasers, interviews with questionnaire respondents interested in the purchase of by-products and a telephone survey of electric utilities using ash marketing firms. The report includes two detailed economic analyses. The first is an analysis of a conventional by-products application scenario which entails bottom ash use for anti-skid material and fly ash use for cement replacement and mineral filler in pavements. The second is an analysis of a combination conventional/hi-tech scenario which entails separation of magnetic ash, segregation of quality pozzolan and manufacture of lightweight aggregate.

  18. Cooperative Studies in the Utilization and Storage of Excess Weapons-Grade Plutonium

    SciTech Connect

    Bolyatko, V. V.

    1998-01-29

    This technical report is a tangible and verifiable deliverable associated with the Nuclear Group subproject “Cooperative Studies in the Utilization and Storage of Excess Weapons-grade Plutonium.” This report is an assessment ofthe work performed by the Russian party from 1 October 1995 through 30 September 1996 regarding milestones defined in the contract between the Moscow Engineering Physics Institute (MEPhI) and the Texas Engineering Experiment Station (TEES). In these interactions, TEES serves as agent of the Amarillo National Resource Center for Plutonium (ANRCP) in the capacity oflead institution for the Nuclear Group of the ANRCP. The official Statement ofWork dated 8 April 1996 enumerates specific milestones and deliverables. In its present form, this report is an edited version ofthe translation submitted to TEES by MEPhI on 7 October 1996. The principal investigators for this subproject are Dr. Paul Nelson of TEES and Dr. Victor Bolyatko of the Moscow Engineering Physics Institute.

  19. Utilization of the human louse genome to study insecticide resistance and innate immune response

    PubMed Central

    Clark, J. Marshall; Yoon, Kyong Sup; Kim, Ju Hyeon; Lee, Si Hyeock; Pittendrigh, Barry R.

    2015-01-01

    Since sequencing the human body louse genome, substantial advances have occurred in the utilization of the information gathered from louse genomes and transcriptomes. Comparatively, the body louse genome contains far fewer genes involved in environmental response, such as xenobiotic detoxification and innate immune response. Additionally, the body louse maintains a primary bacterial endosymbiont, Candidatus Riesia pediculicola, and a number of bacterial pathogens that it vectors, which have genomes that are also reduced in size. Thus, human louse genomes offer unique information and tools for use in advancing our understanding of coevolution among vectors, endosymbionts and pathogens. In this review, we summarize the current literature on the extent of pediculicide resistance, the availability of new pediculicides and information establishing this organism as an efficient model to study how xenobiotic metabolism, which is involved in insecticide resistance, is induced and how insects modify their innate immune response upon bacterial challenge resulting in enhanced vector competence. PMID:25987230

  20. Electric Utility Rate Design Study: comments on An Evaluation of Four Marginal-Costing Methodologies

    SciTech Connect

    Not Available

    1980-06-12

    This report is an extension of NP-24255 (EAPA 6:1820), An Evaluation of Four Marginal Costing Methodologies (RDS No. 66), which summarizes, contrasts, and evaluates four marginal costing methodologies currently in use by various electric utilities. The proponents of the four methodologies evaluated by Temple, Barker, and Sloane (TBS) were asked to comment on the TBS report (RDS No. 66). Other selected reviewers were asked to comment on the TBS report. This report, RDS No. 67, is an anthology of all those comments plus a response to them by TBS. The rebuttal comments from TBS appear first, followed by comments submitted by Ralph Turvey, an authority in microeconomics. The next comments are to the Rate Design Study by members of Advisory Group I, experts in the field of electricity pricing. The next four sections present detailed comments submitted by the four marginal-cost proponents: Cicchetti, Gillen, and Smolensky; Ernst and Ernst; Gordian Associates; and National Economic Research Associates.