WorldWideScience

Sample records for swept area vertical

  1. Noninvasive Characterisation of Foot Reflexology Areas by Swept Source-Optical Coherence Tomography in Patients with Low Back Pain

    Directory of Open Access Journals (Sweden)

    Krishna Dalal

    2013-01-01

    Full Text Available Objective. When exploring the scientific basis of reflexology techniques, elucidation of the surface and subsurface features of reflexology areas (RAs is crucial. In this study, the subcutaneous features of RAs related to the lumbar vertebrae were evaluated by swept source-optical coherence tomography (SS-OCT in subjects with and without low back pain (LBP. Methods. Volunteers without LBP (n=6 (male : female = 1 : 1 and subjects with LBP (n=15 (male : female = 2 : 3 were clinically examined in terms of skin colour (visual perception, localised tenderness (visual analogue scale and structural as well as optical attributes as per SS-OCT. From each subject, 6 optical tomograms were recorded from equidistant transverse planes along the longitudinal axis of the RAs, and from each tomogram, 25 different spatial locations were considered for recording SS-OCT image attributes. The images were analysed with respect to the optical intensity distributions and thicknesses of different skin layers by using AxioVision Rel. 4.8.2 software. The SS-OCT images could be categorised into 4 pathological grades (i.e., 0, 1, 2, and 3 according to distinctness in the visible skin layers. Results. Three specific grades for abnormalities in SS-OCT images were identified considering gradual loss of distinctness and increase in luminosity of skin layers. Almost 90.05% subjects were of mixed type having predominance in certain grades. Conclusion. The skin SS-OCT system demonstrated a definite association of the surface features of healthy/unhealthy RAs with cutaneous features and the clinical status of the lumbar vertebrae.

  2. Noninvasive characterisation of foot reflexology areas by swept source-optical coherence tomography in patients with low back pain.

    Science.gov (United States)

    Dalal, Krishna; Elanchezhiyan, D; Das, Raunak; Dalal, Devjyoti; Pandey, Ravindra Mohan; Chatterjee, Subhamoy; Upadhyay, Ashish Datt; Maran, V Bharathi; Chatterjee, Jyotirmoy

    2013-01-01

    Objective. When exploring the scientific basis of reflexology techniques, elucidation of the surface and subsurface features of reflexology areas (RAs) is crucial. In this study, the subcutaneous features of RAs related to the lumbar vertebrae were evaluated by swept source-optical coherence tomography (SS-OCT) in subjects with and without low back pain (LBP). Methods. Volunteers without LBP (n = 6 (male : female = 1 : 1)) and subjects with LBP (n = 15 (male : female = 2 : 3)) were clinically examined in terms of skin colour (visual perception), localised tenderness (visual analogue scale) and structural as well as optical attributes as per SS-OCT. From each subject, 6 optical tomograms were recorded from equidistant transverse planes along the longitudinal axis of the RAs, and from each tomogram, 25 different spatial locations were considered for recording SS-OCT image attributes. The images were analysed with respect to the optical intensity distributions and thicknesses of different skin layers by using AxioVision Rel. 4.8.2 software. The SS-OCT images could be categorised into 4 pathological grades (i.e., 0, 1, 2, and 3) according to distinctness in the visible skin layers. Results. Three specific grades for abnormalities in SS-OCT images were identified considering gradual loss of distinctness and increase in luminosity of skin layers. Almost 90.05% subjects were of mixed type having predominance in certain grades. Conclusion. The skin SS-OCT system demonstrated a definite association of the surface features of healthy/unhealthy RAs with cutaneous features and the clinical status of the lumbar vertebrae.

  3. Vertical Pointing Weather Radar for Built-up Urban Areas

    DEFF Research Database (Denmark)

    Rasmussen, Michael R.; Thorndahl, Søren; Schaarup-Jensen, Kjeld

    2008-01-01

      A cost effective vertical pointing X-band weather radar (VPR) has been tested for measurement of precipitation in urban areas. Stationary tests indicate that the VPR performs well compared to horizontal weather radars, such as the local area weather radars (LAWR). The test illustrated...

  4. Swept-source optical coherence tomography powered by a 1.3-μm vertical cavity surface emitting laser enables 2.3-mm-deep brain imaging in mice in vivo

    Science.gov (United States)

    Choi, Woo June; Wang, Ruikang K.

    2015-10-01

    We report noninvasive, in vivo optical imaging deep within a mouse brain by swept-source optical coherence tomography (SS-OCT), enabled by a 1.3-μm vertical cavity surface emitting laser (VCSEL). VCSEL SS-OCT offers a constant signal sensitivity of 105 dB throughout an entire depth of 4.25 mm in air, ensuring an extended usable imaging depth range of more than 2 mm in turbid biological tissue. Using this approach, we show deep brain imaging in mice with an open-skull cranial window preparation, revealing intact mouse brain anatomy from the superficial cerebral cortex to the deep hippocampus. VCSEL SS-OCT would be applicable to small animal studies for the investigation of deep tissue compartments in living brains where diseases such as dementia and tumor can take their toll.

  5. A new vertical axis wind turbine design for urban areas

    Science.gov (United States)

    Frunzulica, Florin; Cismilianu, Alexandru; Boros, Alexandru; Dumitrache, Alexandru; Suatean, Bogdan

    2016-06-01

    In this paper we aim at developing the model of a Vertical Axis Wind Turbine (VAWT) with the short-term goal of physically realising this turbine to operate at a maximmum power of 5 kW. The turbine is designed for household users in the urban or rural areas and remote or isolated residential areas (hardly accsessible). The proposed model has a biplane configuration on each arm of the VAWT (3 × 2 = 6 blades), allowing for increased performance of the turbine at TSR between 2 and 2.5 (urban area operation) compared to the classic vertical axis turbines. Results that validate the proposed configuration as well as passive control methods to increase the performance of the classic VAWTs are presented.

  6. Vertical transport of organic matter in the various oceanic areas

    International Nuclear Information System (INIS)

    Handa, Nobuhiko; Hayakawa, Kazuhide

    1993-01-01

    Organic matter produced by the photosynthesis of the phytoplankton is removed from the euphotic layer to the underlying waters by sinking of the particles consisting of both marine snow and fecal pellet. Phytoplankton bloom always enhances the vertical flux of organic matter from the subsurface to deep waters. Turbidity current is another factor to govern the vertical flux of organic carbon especially in the continental shelf to its slope areas. However, no information are available to distinguish the organic materials from these two sources. Stable carbon isotope ratio and fatty acid composition give most promising informations to diagnose the physiological state of the phytoplankton which is one of the source of the organic materials of the sinking particle, because of the extensive variations of the δ 13 C of the phytoplankton cellular organic matter and fatty acid composition due to the phytoplankton growth rate (O'Leary, 1981; Morris et al., 1985). Δ 14 C of the organic matter of the sinking particle will provide an information as to how much organic materials are derived from the phytoplankton growing in the surface and subsurface waters and/or from the resuspended particles of the surface sediment in the continental shelf and its slope areas. Recently we analyzed various samples of the sinking particles collected from the coastal areas of the Antarctica and off Hokkaido, Japan for fatty acids and found that ratios as biomarker to diagnose these growth phases of the phytoplankton growing in the surface to subsurface waters. Thus, we intend to report here these data obtained. (J.P.N.)

  7. Saturated Pool Boiling in Vertical Annulus with Reduced Outflow Area

    International Nuclear Information System (INIS)

    Kang, Myeong Gie

    2012-01-01

    The mechanisms of pool boiling heat transfer have been studied extensively to design efficient heat transfer devices or to assure the integrity of safety related systems. However, knowledge on pool boiling heat transfer in a confined space is still quite limited. The confined nucleate boiling is an effective technique to enhance heat transfer. Improved heat transfer might be attributed to an increase in the heat transfer coefficient due to vaporization from the thin liquid film on the heating surface or increased bubble activity. According to Cornwell and Houston, the bubbles sliding on the heated surface agitate environmental liquid. In a confined space a kind of pulsating flow due to the bubbles is created and, as a result very active liquid agitation is generated. The increase in the intensity of liquid agitation results in heat transfer enhancement. Sometimes a deterioration of heat transfer appears at high heat fluxes for confined boiling. The cause of the deterioration is suggested as active bubble coalescence. Recently, Kang published inflow effects on pool boiling heat transfer in a vertical annulus with closed bottoms. Kang regulated the gap size at the upper regions of the annulus and identified that effects of the reduced gaps on heat transfer become evident as the heat flux increases. This kind of geometry is found in an in-pile test section. Since more detailed analysis is necessary, effects of the outflow area on nucleate pool boiling heat transfer are investigated in this study. Up to the author's knowledge, no previous results concerning to this effect have been published yet

  8. Subsonic Swept Fan Blade

    Science.gov (United States)

    Gallagher, Edward J. (Inventor); Rogers, Thomas H. (Inventor)

    2017-01-01

    A gas turbine engine includes a spool, a turbine coupled to drive the spool, a propulsor coupled to be driven at a at a design speed by the turbine through the spool, and a gear assembly coupled between the propulsor and the spool. Rotation of the turbine drives the propulsor at a different speed than the spool. The propulsor includes a hub and a row of propulsor blades that extend from the hub. Each of the propulsor blades includes an airfoil body. The leading edge of the airfoil body has a swept profile such that, at the design speed, a component of a relative velocity vector of a working gas that is normal to the leading edge is subsonic along the entire radial span.

  9. Aeroelastically coupled blades for vertical axis wind turbines

    Science.gov (United States)

    Paquette, Joshua; Barone, Matthew F.

    2016-02-23

    Various technologies described herein pertain to a vertical axis wind turbine blade configured to rotate about a rotation axis. The vertical axis wind turbine blade includes at least an attachment segment, a rear swept segment, and optionally, a forward swept segment. The attachment segment is contiguous with the forward swept segment, and the forward swept segment is contiguous with the rear swept segment. The attachment segment includes a first portion of a centroid axis, the forward swept segment includes a second portion of the centroid axis, and the rear swept segment includes a third portion of the centroid axis. The second portion of the centroid axis is angularly displaced ahead of the first portion of the centroid axis and the third portion of the centroid axis is angularly displaced behind the first portion of the centroid axis in the direction of rotation about the rotation axis.

  10. Stereological estimation of surface area and barrier thickness of fish gills in vertical sections.

    Science.gov (United States)

    Da Costa, Oscar T F; Pedretti, Ana Carolina E; Schmitz, Anke; Perry, Steven F; Fernandes, Marisa N

    2007-01-01

    Previous morphometric methods for estimation of the volume of components, surface area and thickness of the diffusion barrier in fish gills have taken advantage of the highly ordered structure of these organs for sampling and surface area estimations, whereas the thickness of the diffusion barrier has been measured orthogonally on perpendicularly sectioned material at subjectively selected sites. Although intuitively logical, these procedures do not have a demonstrated mathematical basis, do not involve random sampling and measurement techniques, and are not applicable to the gills of all fish. The present stereological methods apply the principles of surface area estimation in vertical uniform random sections to the gills of the Brazilian teleost Arapaima gigas. The tissue was taken from the entire gill apparatus of the right-hand or left-hand side (selected at random) of the fish by systematic random sampling and embedded in glycol methacrylate for light microscopy. Arches from the other side were embedded in Epoxy resin. Reference volume was estimated by the Cavalieri method in the same vertical sections that were used for surface density and volume density measurements. The harmonic mean barrier thickness of the water-blood diffusion barrier was calculated from measurements taken along randomly selected orientation lines that were sine-weighted relative to the vertical axis. The values thus obtained for the anatomical diffusion factor (surface area divided by barrier thickness) compare favourably with those obtained for other sluggish fish using existing methods.

  11. Vertical view of Apollo 16 landing site located Descartes area lunar nearside

    Science.gov (United States)

    1971-01-01

    A vertical view of the Apollo 16 landing site located in the Descartes area lunar nearside. The overlay indicates the location of the proposed touchdown point for the Apollo 16 Lunar Module. Descartes is located west of the Sea of Nectar and southwest of the Sea of Tranquility. This photograph was taken with a 500mm lens camera from lunar orbit by the Apollo 14 crew.

  12. On the vertical structure of wind gusts

    DEFF Research Database (Denmark)

    Suomi, I.; Gryning, Sven-Erik; Floors, Rogier Ralph

    2015-01-01

    The increasing size of wind turbines, their height and the area swept by their blades have revised the need for understanding the vertical structure of wind gusts. Information is needed for the whole profile. In this study, we analyzed turbulence measurements from a 100m high meteorological mast...... and the turbulence intensity, of which the turbulence intensity was found to dominate over the peak factor in determining the effects of stability and height above the surface on the gust factor. The peak factor only explained 15% or less of the vertical decrease of the gust factor, but determined the effect of gust...... duration on the gust factor. The statistical method to estimate the peak factor did not reproduce the observed vertical decrease in near-neutral and stable conditions and near-constant situation in unstable conditions. Despite this inconsistency, the theoretical method provides estimates for the peak...

  13. Interfacial area transport of subcooled boiling flow in a vertical annulus

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, Caleb S.; Ozar, Basar; Hibiki, Takashi; Ishii, Mamoru, E-mail: ishii@purdue.edu

    2014-03-15

    Highlights: • Discussion of boiling and wall nucleation dataset obtained in a vertical annulus. • Overview of the interfacial area transport equation modeling in boiling flow. • Comparison of bubble departure diameter and frequency with existing models. • Evaluation of the interfacial area transport equation prediction in boiling flow. - Abstract: In an effort to improve the prediction of void fraction and heat transfer characteristics in two-phase systems, the two-group interfacial area transport equation has been developed for use with the two-group two-fluid model. The two-group approach treats spherical/distorted bubbles as Group-1 and cap/slug/churn-turbulent bubbles as Group-2. Therefore, the interfacial area transport of steam-water two-phase flow in a vertical annulus has been investigated experimentally, including bulk flow parameters and wall nucleation characteristics. The theoretical modeling of interfacial area transport equation with phase change terms is introduced and discussed along with the experimental results. Benchmark of the interfacial area transport equation is performed considering the effects of bubble interaction mechanisms such as bubble break-up and coalescence, as well as, effects of phase change mechanisms such as wall nucleation and condensation for subcooled boiling. From the benchmark, sensitivity in the constitutive relations for Group-1 phase change mechanisms, such as wall nucleation and condensation is clear. The Group-2 interfacial area transport is shown to be dominated by the interfacial heat transfer mechanism causing expansion of Group-1 bubbles into Group-2 bubbles in the boiling flow.

  14. Vertical displacement of the brain and the target area during open stereotaxic neurosurgery

    International Nuclear Information System (INIS)

    Wester, K.; Kraekenes, J.

    2001-01-01

    During stereotaxic thalamotomies, we observed that the brain surface was sinking. The study was carried out to investigate to what extent the target area also was displaced and how this would affect the accuracy of the stereotaxic procedure. In 12 thalamotomies, with the patients operated on in the sitting position, we found that the cortical surface sank 0-9 (mean 5) mm during the operation. The vertical co-ordinate of the thalamic target was consequently adjusted per-operatively, and the electrodes were advanced on additional distance of 1-5.5 (mean 3.5) mm in an attempt to compensate for the assumed sinking of the target. This per-operative adjustment was based on the surgeon's experience and the results of macro-stimulation studies. The exact location of the thalamotomy lesion, and thereby the accuracy of the adjustment, was evaluated on 3 months postoperative CT scans. These showed that the intended target was hit with a sufficient degree of accuracy in all the patients, although the vertical co-ordinate had been slightly over-adjusted, as the center of the lesion on the average was located 1 mm below the intended location. Thus, if the vertical position had not been adjusted, the lesion would on the average have been located 2.5 mm too high compared with the intended target. Patients undergoing thalamotomy and other stereotaxic procedures, where a high degree of accuracy is needed, should be operated on in the sitting position. At the thalamic level, the vertical displacement of the target should be adjusted for by additional advancement of the stereotaxic probe. On average, this compensatory adjustment should be about half the per-operative sinking of the cortical surface. (author)

  15. INNOVATIVE SOLUTIONS FOR SMALL SCALE VERTICAL AXIS WIND TURBINES USED IN HARBOURS AND SHORE AREAS

    Directory of Open Access Journals (Sweden)

    IONESCU Raluca Dora

    2014-09-01

    Full Text Available The paper aims to analyse the wind turbine solutions implemented in harbours and on shore areas. Also a thorough study of the blade design solutions for small power Vertical axis wind turbines (VAWTs has been conducted, with their advantages and disadvantages, in order to find the best solution that minimises the loads and helps with the self-starting capabilities of the wind turbine. First are presented all the solutions, next are discussed several research results for each solution and, in the end, a combination of solutions is chosen for our new small power VAWT with a pre-dimensioning analysis.

  16. Vertical farming increases lettuce yield per unit area compared to conventional horizontal hydroponics.

    Science.gov (United States)

    Touliatos, Dionysios; Dodd, Ian C; McAinsh, Martin

    2016-08-01

    Vertical farming systems (VFS) have been proposed as an engineering solution to increase productivity per unit area of cultivated land by extending crop production into the vertical dimension. To test whether this approach presents a viable alternative to horizontal crop production systems, a VFS (where plants were grown in upright cylindrical columns) was compared against a conventional horizontal hydroponic system (HHS) using lettuce ( Lactuca sativa L . cv. "Little Gem") as a model crop. Both systems had similar root zone volume and planting density. Half-strength Hoagland's solution was applied to plants grown in perlite in an indoor controlled environment room, with metal halide lamps providing artificial lighting. Light distribution (photosynthetic photon flux density, PPFD) and yield (shoot fresh weight) within each system were assessed. Although PPFD and shoot fresh weight decreased significantly in the VFS from top to base, the VFS produced more crop per unit of growing floor area when compared with the HHS. Our results clearly demonstrate that VFS presents an attractive alternative to horizontal hydroponic growth systems and suggest that further increases in yield could be achieved by incorporating artificial lighting in the VFS.

  17. Geology of the UE12t No. 3 vertical drill hole, area 12, Nevada Test Site

    International Nuclear Information System (INIS)

    Terry, S.S.

    1975-11-01

    The UE12t No. 3 vertical drill hole, located near the north end of Rainier Mesa, was drilled to a total depth of 663 m (2,176 ft). The UE12t No. 3 vertical hole was drilled to further evaluate the subsurface stratigraphy northwest of the t-tunnel complex area in preparation for mining of the U12t.03 (Husky Pup) drift. The drill hole is collared in the Rainier Mesa Member of the Timber Mountain Tuff and penetrates down the stratigraphic section through the Paintbrush Tuff, the welded Grouse Canyon Member of the Belted Range Tuff, tunnel beds 5-3, the Tub Spring Member of the Belted Range Tuff, tunnel bed 2, Crater Flat Tuff, tunnel bed 1, Redrock Valley Tuff, and bottoms in older Tertiary tuffaceous and Paleozoic quartzite rubble having a partially argillized, tuffaceous, soillike matrix. The tuff of Dead Horse Flat and the bedded and ash-flow tuffs of Area 20 were not differentiated in the logging of this drill hole. Stratigraphy, structure, engineering geology, and physical properties and their relation to tunneling are discussed

  18. Lateral, Vertical, and Longitudinal Source Area Connectivity Drive Runoff and Carbon Export Across Watershed Scales

    Science.gov (United States)

    Zimmer, Margaret A.; McGlynn, Brian L.

    2018-03-01

    Watersheds are three-dimensional hydrologic systems where the longitudinal expansion/contraction of stream networks, vertical connection/disconnection between shallow and deep groundwater systems, and lateral connectivity of these water sources to streams mediate runoff production and nutrient export. The connectivity of runoff source areas during both baseflow and stormflow conditions and their combined influence on biogeochemical fluxes remain poorly understood. Here we focused on a set of 3.3 and 48.4 ha nested watersheds (North Carolina, USA). These watersheds comprise ephemeral and intermittent runoff-producing headwaters and perennial runoff-producing lowlands. Within these landscape elements, we characterized the timing and magnitude of precipitation, runoff, and runoff-generating flow paths. The active surface drainage network (ASDN) reflected connectivity to, and contributions from, source areas that differed under baseflow and stormflow conditions. The baseflow-associated ASDN expanded and contracted seasonally, driven by the rise and fall of the seasonal water table. Superimposed on this were event-activated source area contributions driven by connectivity to surficial and shallow subsurface flow paths. Frequently activated shallow flow paths also caused increased in-stream dissolved organic carbon (DOC) concentrations with increases in runoff across both watershed scales. The spread and variability within this DOC-runoff relationship was driven by a seasonal depletion of DOC from continual shallow subsurface flow path activation and subsequent replenishment from autumn litterfall. Our findings suggest that hydrobiogeochemical signals at larger watershed outlets can be driven by the expansion, contraction, and connection of lateral, longitudinal, and vertical source areas with distinct runoff generation processes.

  19. A New Type of Captive Balloon for Vertical Meteorological Observation in Urban Area

    Science.gov (United States)

    Nakamura, M.; Sakai, S.; Ono, K.

    2010-12-01

    Many meteorological observations in urban area have been made in recent years in order to investigate the mechanism of heat island. However, there are few data of cooling process in urban area. For this purpose, high density observations in both space and time are required. Generally vertical meteorological observations can be made by towers, radars, balloons. These methods are limited by urban area conditions. Among these methods, a captive balloon is mainly used to about a hundred meter from ground in a vertical meteorological observation. Small airships called kytoons or advertising balloons, for example. Conventional balloons are, however, influenced by the wind and difficult to keep the specified position. Moreover, it can be dangerous to conduct such observations in the highly build-up area. To overcome these difficulties, we are developing a new type of captive balloon. It has a wing form to gain lift and keep its position. It is also designed small to be kept in a carport. It is made of aluminum film and polyester cloth in order to attain lightweight solution. We have tried floating a balloon like NACA4424 for several years. It was difficult to keep a wing form floating up over 100 meters from ground because internal pressure was decreased by different temperature. The design is changed in this year. The balloon that has wing form NACA4415 is similar in composition to an airplane. It has a big gasbag with airship form and two wing form. It is able to keep form of a wing by high internal pressure. We will report a plan for the balloon and instances of some observations.

  20. One-group interfacial area transport in vertical air-water bubbly flow

    International Nuclear Information System (INIS)

    Wu, Q.; Kim, S.; Ishii, M.; Beus, S.G.

    1997-01-01

    In the two-fluid model for two-phase flows, interfacial area concentration is one of the most important closure relations that should be obtained from careful mechanistic modeling. The objective of this study is to develop a one-group interfacial area transport equation together with the modeling of the source and sink terms due to bubble breakage and coalescence. For bubble coalescence, two mechanisms are considered to be dominant in vertical two-phase bubbly flow. These are the random collisions between bubbles due to turbulence in the flow field, and the wake entrainment process due to the relative motion of the bubbles in the wake region of a seeding bubble. For bubble breakup, the impact of turbulent eddies is considered. These phenomena are modeled individually, resulting in a one-group interfacial area concentration transport equation with certain parameters to be determined from experimental data. Compared to the measured axial distribution of the interfacial area concentration under various flow conditions, these parameters are obtained for the reduced one-group, one-dimensional transport equation. The results indicate that the proposed models for bubble breakup and coalescence are appropriate

  1. Light hydrocarbons vertical profiles and fluxes in a french rural area

    Science.gov (United States)

    Kanakidou, M.; Bonsang, B.; Lambert, G.

    By means of manned hot air balloon flights, in July 1986, an experiment was conducted in a rural area of southwest France in order to determine the production at ground level of non-methane hydrocarbons in the C 2-C 6 range. Flux determinations were based on vertical profiles before and after the development of a temperature inversion layer which allowed the measurement of the NMHC accumulation close to ground level. The main species produced in the late afternoon were acetylene, propane, ethene, propene and ethane with production rates of the order of 0.5 to 2 × 10 -4g of C m -2 h -1. Isoprene was found to be the main other unsaturated species also produced. The fluxes and the atmospheric content of the air column before the inversion are consistent with an average OH radical concentration of 2 × 10 6 cm -3.

  2. Fabrication of a Horizontal and a Vertical Large Surface Area Nanogap Electrochemical Sensor

    Directory of Open Access Journals (Sweden)

    Jules L. Hammond

    2016-12-01

    Full Text Available Nanogap sensors have a wide range of applications as they can provide accurate direct detection of biomolecules through impedimetric or amperometric signals. Signal response from nanogap sensors is dependent on both the electrode spacing and surface area. However, creating large surface area nanogap sensors presents several challenges during fabrication. We show two different approaches to achieve both horizontal and vertical coplanar nanogap geometries. In the first method we use electron-beam lithography (EBL to pattern an 11 mm long serpentine nanogap (215 nm between two electrodes. For the second method we use inductively-coupled plasma (ICP reactive ion etching (RIE to create a channel in a silicon substrate, optically pattern a buried 1.0 mm × 1.5 mm electrode before anodically bonding a second identical electrode, patterned on glass, directly above. The devices have a wide range of applicability in different sensing techniques with the large area nanogaps presenting advantages over other devices of the same family. As a case study we explore the detection of peptide nucleic acid (PNA−DNA binding events using dielectric spectroscopy with the horizontal coplanar device.

  3. New particle formation at ground level and in the vertical column over the Barcelona area

    Science.gov (United States)

    Minguillón, M. C.; Brines, M.; Pérez, N.; Reche, C.; Pandolfi, M.; Fonseca, A. S.; Amato, F.; Alastuey, A.; Lyasota, A.; Codina, B.; Lee, H.-K.; Eun, H.-R.; Ahn, K.-H.; Querol, X.

    2015-10-01

    The vertical profiles (up to 975 m a.s.l.) of ultrafine and micronic particles across the planetary boundary layer and the free troposphere over a Mediterranean urban environment were investigated. Measurements were carried out using a tethered balloon equipped with a miniaturized condensation particle counter, a miniaturized optical particle counter, a micro-aethalometer, a rotating impactor, and meteorological instrumentation. Simultaneous ground measurements were carried out at an urban and a regional background site. New particle formation episodes initiating in the urban area were observed under high insolation conditions. The precursors were emitted by the city and urban photochemically-activated nucleation occurred both at high atmospheric levels (tens to hundreds of meters) and at ground level. The new particle formation at ground level was limited by the high particulate matter concentrations recorded during the morning traffic rush hours that increase the condensation sink and prevent new particle formation, and therefore restricted to midday and early afternoon. The aloft new particle formation occurred earlier as the thermally ascending polluted air mass was diluted. The regional background was only affected from midday and early afternoon when sea and mountain breezes transported the urban air mass after particle growth. These events are different from most new particle formation events described in literature, characterized by a regionally originated nucleation, starting early in the morning in the regional background and persisting with a subsequent growth during a long period. An idealized and simplified model of the spatial and time occurrence of these two types of new particle formation episodes into, around and over the city was elaborated.

  4. Combined Structural Optimization and Aeroelastic Analysis of a Vertical Axis Wind Turbine

    DEFF Research Database (Denmark)

    Roscher, Björn; Ferreira, Carlos Simao; Bernhammer, Lars O.

    2015-01-01

    Floating offshore wind energy poses challenges on the turbine design. A possible solution is vertical axis wind turbines, which are possibly easier to scale-up and require less components (lower maintenance) and a smaller floating structure than horizontal axis wind turbines. This paper presents...... a structural optimization and aeroelastic analysis of an optimized Troposkein vertical axis wind turbine to minimize the relation between the rotor mass and the swept area. The aeroelastic behavior of the different designs has been analyzed using a modified version of the HAWC2 code with the Actuator Cylinder...... model to compute the aerodynamics of the vertical axis wind turbine. The combined shape and topology optimization of a vertical axis wind turbine show a minimum mass to area ratio of 1.82 kg/m2 for blades with varying blade sections from a NACA 0040 at the attachment points to a NACA 0015...

  5. Compact vertical take-off and landing aerial vehicle for monitoring tasks in dense urban areas

    Directory of Open Access Journals (Sweden)

    Sergii FIRSOV

    2015-09-01

    Full Text Available Using of aerial vehicles with onboard sensory and broadcasting apparatus for monitoring a variety of objects and processes in inaccessible places of the city. A hardware and software package for the task solving is proposed in the article. Presented vehicle is a vertical take-off and landing airplane of tail-sitter type.

  6. Vertical Land Utilization by Means of Storey Housing Development in Urban Area

    Directory of Open Access Journals (Sweden)

    Arie Sukanti

    2011-05-01

    Full Text Available Many international covenants and constitutions have recognized housing and shelter needs as one of many human right aspects. This paper intends to clarify the particular issues relating to paragraph 19 of the United Nations Millennium Declaration, on resolving city slum problems. The Declaration has also embedded initiative to achieve a significant improvement in the lives of at least 100 million slum dwellers as proposed in the “Cities without Slums” by 2020. In the local perspectives, based on existing regulations analysis, the Special Region (DKI of Jakarta has many problems on forthcoming implementation. Vertical land utilization model by way of storey houses development becomes an alternative to settle the demographic and housing problems. More legal research needs to be conducted to find the best effective national policy in the future. Urban land use, proposed as starting points, will be able to explore how to provide and undertake vertical land utilization and city planning to resolve city slums problems by providing both housing needs and city attractiveness as an integrated planning.

  7. The advantages of a swept source optical coherence tomography system in the evaluation of occlusal disorders

    Science.gov (United States)

    Marcauteanu, Corina; Bradu, Adrian; Sinescu, Cosmin; Topala, Florin Ionel; Negrutiu, Meda Lavinia; Duma, Virgil Florin; Podoleanu, Adrian Gh.

    2014-01-01

    Occlusal disorders are characterized by multiple dental and periodontal signs. Some of these are reversible (such as excessive tooth mobility, fremitus, tooth pain, migration of teeth in the absence of periodontitis), some are not (pathological occlusal/incisal wear, abfractions, enamel cracks, tooth fractures, gingival recessions). In this paper we prove the advantages of a fast swept source OCT system in the diagnosis of pathological incisal wear, a key sign of the occlusal disorders. On 15 extracted frontal teeth four levels of pathological incisal wear facets were artificially created. After every level of induced defect, OCT scanning was performed. B scans were acquired and 3D reconstructions were generated. A swept source OCT instrument is used in this study. The swept source is has a central wavelength of 1050 nm and a sweeping rate of 100 kHz. A depth resolution determined by the swept source of 12 μm in air was experimentally measured. The pathological incisal wear is qualitatively observed on the B-scans as 2D images and 3D reconstructions (volumes). For quantitative evaluations of volumes, we used the Image J software. Our swept source OCT system has several advantages, including the ability to measure (in air) a minimal volume of 2352 μm3 and to collect high resolution volumetric images in 2.5 s. By calculating the areas of the amount of lost tissue corresponding to each difference of B-scans, the final volumes of incisal wear were obtained. This swept source OCT method is very useful for the dynamic evaluation of pathological incisal wear.

  8. Influences of radiation and leaf area vertical distribution on the growth of Chinese fir young plantation with different densities

    International Nuclear Information System (INIS)

    Wang Lili

    1990-01-01

    A study on the radiation and leaf area vertical distribution in relation to the growth of 8-year-old Chinese fir plantations of 5 densities was conducted. The leaf area vertical distribution and LAI were closely related to stem density. The crown form varies from conic to cylindric with the increase of stem density. The LAI rises at first and then declines with the increase of density. The extinction of radiation sharpened when the crown density increased. The extinction leveled at the depth of 3/4 forest heights from the tops of forest canopies. Calculating the extinction coefficients by means of accumulated leaf area index separately for each crown layer can minimize the errors caused by the irregularity of leaf distribution. Four indices, i.e., absorption of radiation, LAI,biomass of individual tree and averaged annual increment of biomass were used to have a comprehensive evaluation on the growth of Chinese fir of 5 densities. The results showed that the plantation with a stem density of 2m × 1 m was the best one among the 5 young plantations

  9. Kind of approximate theoretical calculating formula of heat-exchange area for the vertical U-bend tube natural-circuit steam generator

    International Nuclear Information System (INIS)

    Luo Mingkun; Wang Fei; Huang Wei; Zhang Wenqi; Zhao Shan; Lu Lianghong

    2001-01-01

    A kind of approximate theoretical calculating formula of the vertical U-bend tube natural-circuit steam generator is deduced by using an approximate method, the results of this formula is compared with the heat exchanging areas of the real vertical U-bend tube natural-circuit steam generators, the absolute errors of them are below 8%

  10. Synthesizing monochromatic 3-D images by multiple-exposure rainbow holography with vertical area-partition approach

    Institute of Scientific and Technical Information of China (English)

    翟宏琛; 王明伟; 刘福民; 母国光

    2002-01-01

    We report for the first time the theoretical analysis and experimental results of a white-light reconstructed monochromatic 3-D image synthesizing tomograms by multiple rainbow holo-graphy with vertical-area partition (VAP) approach. The theoretical and experimental results show that 3-D monochromatic image can be synthesized by recording the master hologram by VAP ap-proach without any distortions either in gray scale or in geometrical position. A 3-D monochromatic image synthesized from a series of medical tomograms is presented in this paper for the first time.

  11. Predicted tyre-soil interface area and vertical stress distribution based on loading characteristics

    DEFF Research Database (Denmark)

    Schjønning, Per; Stettler, M.; Keller, Thomas

    2015-01-01

    The upper boundary condition for all models simulating stress patterns throughout the soil profile is the stress distribution at the tyre–soil interface. The so-called FRIDA model (Schjønning et al., 2008. Biosyst. Eng. 99, 119–133) treats the contact area as a superellipse and has been shown...... of the actual to recommended inflation pressure ratio. We found that VT and Kr accounted for nearly all variation in the data with respect to the contact area. The contact area width was accurately described by a combination of tyre width and Kr, while the superellipse squareness parameter, n, diminished...... slightly with increasing Kr. Estimated values of the contact area length related to observed data with a standard deviation of about 0.06 m. A difference between traction and implement tyres called for separate prediction equations, especially for the contact area. The FRIDA parameters α and β, reflecting...

  12. Envisioning Urban Farming for Food Security during the Climate Change Era. Vertical Farm within Highly Urbanized Areas

    Science.gov (United States)

    Januszkiewicz, Krystyna; Jarmusz, Małgorzata

    2017-10-01

    Global climate change constitutes a serious threat to global security including food production in the following decades. This paper is focused on a new possibility and advisability of creating a systemic solution to resolve the problem of food security in highly-urbanized areas. The first part of the paper deal with historical development vertical farms ideas and defines the main environmental and spatial constrains also it indicates that vertical farms are going to be part of the future horticultural production. The second part presents results of the research program undertaken at West Pomeranian University of Technology in Szczecin by authors. The program goes on to attempt to solve the problem through architectural design. This study highlights an integrating large-scale horticultural production directly into the cities, where the most of the food consumption takes place. In conclusions emphasizes, that the design will force architects, engineers and urban planners to completely revise and redefine contemporary design process and understanding of the idea-fix of sustainable design. To successfully migrate food production from extensive rural areas to dense environment of city centres, a new holistic approach, integrating knowledge and advances of multiple fields of science, have to develop.

  13. Stability and transition on swept wings

    Science.gov (United States)

    Stuckert, Greg; Herbert, Thorwald; Esfahanian, Vahid

    1993-01-01

    This paper describes the extension and application of the Parabolized Stability Equations (PSE) to the stability and transition of the supersonic three-dimensional laminar boundary layer on a swept wing. The problem formulation uses a general coordinate transformation for arbitrary curvilinear body-fitted computational grids. Some testing using these coordinates is briefly described to help validate the software used for the investigation. The disturbance amplitude ratios as a function of chord position for supersonic (Mach 1.5) boundary layers on untapered, untwisted wings of different sweep angles are then presented and compared with those obtained from local parallel analyses.

  14. Experimental and analytical study of interfacial area transport phenomena in a vertical two-phase flow

    International Nuclear Information System (INIS)

    Huh, Byung-Gil; Euh, Dong-Jin; Yun, Byong-Jo; Youn, Young-Jung; Yoon, Han-Yeong; Song, Chul-Hwa

    2005-03-01

    The number density transport equations for various bubble groups are used to predict the void fraction and the interfacial area concentration. As the closure relations for number density transport equation, the coalescence due to random collisions and the breakup due to the impact of turbulent eddies is modified based on the previous studies and the bubble expansion term due to the pressure reduction is considered. Also, the coalescence due to a wake entrainment is modeled newly to apply to the number density transport equation. In order to predict the local experimental data, the code is developed that the two-fluid model is coupled systematically with the number density transport equation for each bubble group. As for the results of the numerical analysis, the void fraction and interfacial area concentration are predicted well by the developed code and models although some deviations exist in the values between the prediction and experiment, especially, for the high void fraction conditions

  15. Experimental and analytical study of interfacial area transport phenomena in a vertical two-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Byung-Gil; Euh, Dong-Jin; Yun, Byong-Jo; Youn, Young-Jung; Yoon, Han-Yeong; Song, Chul-Hwa

    2005-03-01

    The number density transport equations for various bubble groups are used to predict the void fraction and the interfacial area concentration. As the closure relations for number density transport equation, the coalescence due to random collisions and the breakup due to the impact of turbulent eddies is modified based on the previous studies and the bubble expansion term due to the pressure reduction is considered. Also, the coalescence due to a wake entrainment is modeled newly to apply to the number density transport equation. In order to predict the local experimental data, the code is developed that the two-fluid model is coupled systematically with the number density transport equation for each bubble group. As for the results of the numerical analysis, the void fraction and interfacial area concentration are predicted well by the developed code and models although some deviations exist in the values between the prediction and experiment, especially, for the high void fraction conditions.

  16. Chewing side, bite force symmetry, and occlusal contact area of subjects with different facial vertical patterns

    Directory of Open Access Journals (Sweden)

    Simone Guimarães Farias Gomes

    2011-10-01

    Full Text Available Craniofacial dimensions influence oral functions; however, it is not known whether they are associated with function asymmetry. The objective of this study was to evaluate chewing side preference and lateral asymmetry of occlusal contact area and bite force of individuals with different craniofacial patterns. Seventy-eight dentate subjects were divided into 3 groups according to the VERT index as follows: (1 mesofacial, (2 brachyfacial and (3 dolichofacial. Chewing side preference was evaluated using jaw tracking equipment, occlusal contact area was measured by silicon registration of posterior teeth, and bite force was measured unilaterally on molar regions using 2.25 mm-thick sensors. Statistical analysis was performed using ANOVA on Ranks, Student's t-test, and Mann-Whitney tests at a 5% significance level. Mesofacial, brachyfacial, and dolichofacial subjects presented more occlusal contact area on the left side. Only dolichofacial subjects showed lateral asymmetry for bite force, presenting higher force on the left side. No statistically significant differences were found for chewing side preference among all groups. Within the limitations of this study, it can be concluded that craniofacial dimensions play a role in asymmetry of bite force. ClinicalTrials.gov ID: NCT01286363.

  17. Imaging of noncarious cervical lesions by means of a fast swept source optical coherence tomography system

    Science.gov (United States)

    Stoica, Eniko T.; Marcauteanu, Corina; Bradu, Adrian; Sinescu, Cosmin; Topala, Florin Ionel; Negrutiu, Meda Lavinia; Duma, Virgil Florin; Podoleanu, Adrian Gh.

    2014-01-01

    Non-carious cervical lesions (NCCL) are defined as the loss of tooth substance at the cemento-enamel junction and are caused by abrasion, erosion and/or occlusal overload. In this paper we proved that our fast swept source OCT system is a valuable tool to track the evolution of NCCL lesions in time. On several extracted bicuspids, four levels of NCCL were artificially created. After every level of induced lesion, OCT scanning was performed. B scans were acquired and 3D reconstructions were generated. The swept source OCT instrument used in this study has a central wavelength of 1050 nm, a sweeping range of 106 nm (measured at 10 dB), an average output power of 16 mW and a sweeping rate of 100 kHz. A depth resolution determined by the swept source of 12 μm in air was experimentally obtained. NCCL were measured on the B-scans as 2D images and 3D reconstructions (volumes). For quantitative evaluations of volumes, the Image J software was used. By calculating the areas of the amount of lost tissue corresponding to each difference of Bscans, the final volumes of NCCL were obtained. This swept source OCT method allows the dynamic diagnosis of NCCL in time.

  18. Role of disc area and trabecular bone density on lumbar spinal column fracture risk curves under vertical impact.

    Science.gov (United States)

    Yoganandan, Narayan; Moore, Jason; Pintar, Frank A; Banerjee, Anjishnu; DeVogel, Nicholas; Zhang, JiangYue

    2018-04-27

    While studies have been conducted using human cadaver lumbar spines to understand injury biomechanics in terms of stability/energy to fracture, and physiological responses under pure-moment/follower loads, data are sparse for inferior-to-superior impacts. Injuries occur under this mode from underbody blasts. determine role of age, disc area, and trabecular bone density on tolerances/risk curves under vertical loading from a controlled group of specimens. T12-S1 columns were obtained, pretest X-rays and CTs taken, load cells attached to both ends, impacts applied at S1-end using custom vertical accelerator device, and posttest X-ray, CT, and dissections done. BMD of L2-L4 vertebrae were obtained from QCT. Survival analysis-based Human Injury Probability Curves (HIPCs) were derived using proximal and distal forces. Age, area, and BMD were covariates. Forces were considered uncensored, representing the load carrying capacity. The Akaike Information Criterion was used to determine optimal distributions. The mean forces, ±95% confidence intervals, and Normalized Confidence Interval Size (NCIS) were computed. The Lognormal distribution was the optimal function for both forces. Age, area, and BMD were not significant (p > 0.05) covariates for distal forces, while only BMD was significant for proximal forces. The NCIS was the lowest for force-BMD covariate HIPC. The HIPCs for both genders at 35 and 45 years were based on population BMDs. These HIPCs serve as human tolerance criteria for automotive, military, and other applications. In this controlled group of samples, BMD is a better predictor-covariate that characterizes lumbar column injury under inferior-to-superior impacts. Published by Elsevier Ltd.

  19. New model of the vertical crustal movements in the area of Poland

    OpenAIRE

    Kowalczyk, Kamil

    2006-01-01

    In 2003 the fourth levelling campaign has been finished in Poland. This campaign, together with the previous one carried out in 1974–1982, gave a very good opportunity to determine the land uplift in the area of Poland. The paper describes shortly the third and fourth campaigns, the computation of the relative land uplift, computation of land uplift referred to the mean sea level and modeling the land uplift by the least-squares collocation method. Obtained results are compared with the compu...

  20. Analysis of vertical movements detected by radar interferometry in urban areas

    Czech Academy of Sciences Publication Activity Database

    Kadlečík, Pavel; Schenk, Vladimír; Seidlová, Zuzana; Schenková, Zdeňka

    2010-01-01

    Roč. 7, č. 3 (2010), s. 371-380 ISSN 1214-9705. [Czech-Polish Workshop on Recent Geodynamics of the Sudety Mts. and Adjacent Areas /10./. Szklarska Poreba, 05.11.2009-07.11.2009] R&D Projects: GA MŠk(CZ) LC506; GA AV ČR 1QS300460551 Institutional research plan: CEZ:AV0Z30460519 Keywords : InSAR * PSI * subsidence Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 0.452, year: 2010 www.irsm.cas.cz/abstracts/AGG/03_10/15_Kadlecik.pdf

  1. Vertical Displacement of the Surface Area over the Leakage to the Transverse salt Mine in 1992-2012

    Science.gov (United States)

    Lipecki, Tomasz

    2018-03-01

    The leakage of water in the salt mine caused considerable deformation of the surface. This article shows the vertical displacement in the area of leakage to the mine excavation, measured by precision leveling, carried out from the first days of leakage in 1992 until 2012. The geological and hydrogeological conditions of the mine, as well as the associated water hazards were described, which in conjunction with the inconvenient location of the excavation site in the northern frontage of the Carpathians and also inadequately conducted mining operations, contributed to the risk of flooding mine. The analysis of the vertical movements of the surface - subsidence and uplift - were present as well as the process of formation of the depression trough in the form of maps and graphs. The analyzes were based on 49 measurement series, starting from the first days of the disaster within the next 20 years. The course of development of the depression trough and the condition of the surface after stopping the water from the rock mass has been shown, which caused the surface to uplift.

  2. Vertical Displacement of the Surface Area over the Leakage to the Transverse salt Mine in 1992–2012

    Directory of Open Access Journals (Sweden)

    Lipecki Tomasz

    2018-01-01

    Full Text Available The leakage of water in the salt mine caused considerable deformation of the surface. This article shows the vertical displacement in the area of leakage to the mine excavation, measured by precision leveling, carried out from the first days of leakage in 1992 until 2012. The geological and hydrogeological conditions of the mine, as well as the associated water hazards were described, which in conjunction with the inconvenient location of the excavation site in the northern frontage of the Carpathians and also inadequately conducted mining operations, contributed to the risk of flooding mine. The analysis of the vertical movements of the surface – subsidence and uplift – were present as well as the process of formation of the depression trough in the form of maps and graphs. The analyzes were based on 49 measurement series, starting from the first days of the disaster within the next 20 years. The course of development of the depression trough and the condition of the surface after stopping the water from the rock mass has been shown, which caused the surface to uplift.

  3. Inclusive Development through Providing Vertical Housing for Low Income Family in Yogyakarta Urban Areas

    Directory of Open Access Journals (Sweden)

    Rini Rachmawati

    2017-12-01

    Full Text Available Inclusive development is mean to accommodate the marginalized people, most of whom are the poor with problem of fulfilling their need of housing. The government has tried hard to meet the need of housing by constructing rusunawa. This paper is aimed at describing about the provision and uses of rusunawa, both in cities and peri urban area by studying the cases in the City of Yogyakarta, Sleman Regency, and Bantul Regency. The study was conducted by doing observation and both structured and in-depth interviews. The research results show that rusunawa was viewed as one solutions to help low-income family in fulfilling their need of housing. In some cases in the City of Yogyakarta, rusunawa plays an important role in preventing the settlement along both sides of rivers from becoming slum areas. Rusunawa in both Regencies of Sleman and Bantul are located near the city so it is easy for the settlers to get to their workplace. The construction of rusunawa has also paid attention to the disabled by providing special facilities. The same case is providing playground for children and facilities for early education for young kids. However, there have not been special facilities for the elderly and pregnant women.

  4. Vertical profiles of lung deposited surface area concentration of particulate matter measured with a drone in a street canyon.

    Science.gov (United States)

    Kuuluvainen, Heino; Poikkimäki, Mikko; Järvinen, Anssi; Kuula, Joel; Irjala, Matti; Dal Maso, Miikka; Keskinen, Jorma; Timonen, Hilkka; Niemi, Jarkko V; Rönkkö, Topi

    2018-05-23

    The vertical profiles of lung deposited surface area (LDSA) concentration were measured in an urban street canyon in Helsinki, Finland, by using an unmanned aerial system (UAS) as a moving measurement platform. The street canyon can be classified as an avenue canyon with an aspect ratio of 0.45 and the UAS was a multirotor drone especially modified for emission measurements. In the experiments of this study, the drone was equipped with a small diffusion charge sensor capable of measuring the alveolar LDSA concentration of particles. The drone measurements were conducted during two days on the same spatial location at the kerbside of the street canyon by flying vertically from the ground level up to an altitude of 50 m clearly above the rooftop level (19 m) of the nearest buildings. The drone data were supported by simultaneous measurements and by a two-week period of measurements at nearby locations with various instruments. The results showed that the averaged LDSA concentrations decreased approximately from 60 μm 2 /cm 3 measured close to the ground level to 36-40 μm 2 /cm 3 measured close to the rooftop level of the street canyon, and further to 16-26 μm 2 /cm 3 measured at 50 m. The high-resolution measurement data enabled an accurate analysis of the functional form of vertical profiles both in the street canyon and above the rooftop level. In both of these regions, exponential fits were used and the parameters obtained from the fits were thoroughly compared to the values found in literature. The results of this study indicated that the role of turbulent mixing caused by traffic was emphasized compared to the street canyon vortex as a driving force of the dispersion. In addition, the vertical profiles above the rooftop level showed a similar exponential decay compared to the profiles measured inside the street canyon. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Interfacial area transport of vertical upward air-water two-phase flow in an annulus at elevated pressures

    International Nuclear Information System (INIS)

    Ozar, Basar; Hibiki, Takashi; Ishii, Mamoru; Euh, Dong-Jin

    2009-01-01

    The interfacial area transport of vertical, upward, air-water two-phase flows in an annular channel has been investigated at different system pressures. The inner and outer diameters of the annular channel were 19.1 mm and 38.1 mm, respectively. Twenty three inlet flow conditions were selected, which coverED bubbly, cap-slug, and churn-turbulent flows. These flow conditions also overlapped with twelve conditions of our previous study for comparison. The local flow parameters, such as void fractions, interfacial area concentrations (IAC), and bubble interface velocities, were measured at nine radial positions for the three axial locations (z/D h =52, 149 and 230) and converted into area-averaged parameters. The axial evolutions of local flow structure was interpreted in terms of bubble coalescence, breakup, expansion of the gas-phase due to pressure drop and system pressure. An assessment of interfacial area transport equation (IATE) was made and compared with the experimental data. A discussion of the comparison between model prediction and the experimental results were made. (author)

  6. Using Vertical Electrical Soundings for Characterizing Hydrogeological and Tectonic Settings in Deir El-Adas Area, Yarmouk Basin, Syria

    Science.gov (United States)

    Al-Fares, Walid

    2016-06-01

    The present study is aimed at characterizing the subsurface geological and tectonic structure in Deir El-Adas area, by using Vertical Electrical Sounding survey (VES) and hydrogeological investigations, in order to determine the causes of the failure for the majority of the wells drilled in the area. The survey data was treated in three different approaches including direct VES inversion, pseudo-2D method and horizontal profiling, in order to maximize the reliability of the data interpretation. The results revealed the presence of a local faulted anticline structure at the top of the Paleogene formation, underneath the basaltic outcrops where Deir El-Adas village is situated. The appearance of this subsurface anticline structure has complicated the local hydro-geological situation, and most likely led to limitation of the groundwater recharge in the area. Moreover, the performed piezometric and discharge maps indicated the presence of a notable groundwater watershed, in addition to feeble water productivity of the wells drilled adjacent to Deir El-Adas, mostly related to the subsurface geological and tectonic settings in the area.

  7. Modelling horizontal and vertical concentration profiles of ozone and oxides of nitrogen within high-latitude urban areas

    International Nuclear Information System (INIS)

    Nicholson, J.P.; Weston, K.J.

    2001-01-01

    Urban ozone concentrations are determined by the balance between ozone destruction, chemical production and supply through advection and turbulent down-mixing from higher levels. At high latitudes, low levels of solar insolation and high horizontal advection speeds reduce the photochemical production and the spatial ozone concentration patterns are largely determined by the reaction of ozone with nitric oxide and dry deposition to the surface. A Lagrangian column model has been developed to simulate the mean (monthly and annual) three-dimensional structure in ozone and nitrogen oxides (NO x ) concentrations in the boundary-layer within and immediately around an urban area. The short-time-scale photochemical processes of ozone and NO x , as well as emissions and deposition to the ground, are simulated. The model has a horizontal resolution of 1x1km and high resolution in the vertical. It has been applied over a 100x100km domain containing the city of Edinburgh (at latitude 56 o N) to simulate the city-scale processes of pollutants. Results are presented, using averaged wind-flow frequencies and appropriate stability conditions, to show the extent of the depletion of ozone by city emissions. The long-term average spatial patterns in the surface ozone and NO x concentrations over the model domain are reproduced quantitatively. The model shows the average surface ozone concentrations in the urban area to be lower than the surrounding rural areas by typically 50% and that the areas experiencing a 20% ozone depletion are generally restricted to within the urban area. The depletion of the ozone concentration to less than 50% of the rural surface values extends only 20m vertically above the urban area. A series of monitoring sites for ozone, nitric oxide and nitrogen dioxide on a north-south transect through the city - from an urban, through a semi-rural, to a remote rural location - allows the comparison of modelled with observed data for the mean diurnal cycle of ozone

  8. Vertical profiles and enrichment pattern of natural radionuclides in monazite areas of coastal Kerala

    International Nuclear Information System (INIS)

    Shetty, P.K.; Narayana, Y.; Siddappa, K.

    2006-01-01

    Detailed studies on radionuclides concentration in different environmental matrices of high background areas were undertaken in the coastal areas of Karunagapalli, Chavara, Neendakara and Kollam to study the distribution and enrichment of the radionuclides in the region. The sand samples collected at different distances from sea waterline and at different depths, were analysed for primordial radionuclides by gamma spectrometry. The activity of primordial radionuclides was determined for the different size fractions of sand to study the enrichment pattern. The highest activity was found confined in 125-63 μm particle size fraction in sand. The minimum 232 Th activity was 9.4 Bq kg -1 , found in Kollam at a depth of 10-20 cm, 40 m away from waterline in 500-250 μm particle size fraction and maximum activity of 136,811.2 Bq kg -1 was observed in Chavara in grains of size 125-63 μm at a depth of 0-10 cm for a sample collected 20 m away from waterline. The lowest 226 Ra activity observed was 29.6 Bq kg -1 at Kollam beach for a sample 40 m away from waterline in grains of size 1000-500 μm and at a depth of 20-30 cm and the highest activity observed was 10,309 Bq kg -1 in grains of size 125-63 μm for a sample collected at a distance 20 m away from waterline and at a depth of 0-10 cm. The activity of 4 K was below detectable level in most of the samples collected from the high background monazite area. The 232 Th, 226 Ra activities decrease with depth for the samples collected 20 m away from the waterline and increase with depth for the samples collected 40 m away from the waterline at Chavara and Kollam beaches. No definite correlation was found between variation of the concentrations of 232 Th and 226 Ra with depth at Karunagapalli and Neendakara beach sands. There exists a strong correlation between 226 Ra and 232 Th activities in the region. The results of these investigations are presented and discussed in this paper

  9. FDML swept source at 1060 nm using a tapered amplifier

    DEFF Research Database (Denmark)

    Marschall, Sebastian; Klein, Thomas; Wieser, Wolfgang

    2010-01-01

    We present a novel frequency-swept light source working at 1060nm that utilizes a tapered amplifier as gain medium. These devices feature significantly higher saturation power than conventional semiconductor optical amplifiers and can thus improve the limited output power of swept sources in this...... an axial resolution of 15 µm in air (~11µm in tissue) for OCT applications can be achieved....

  10. Pigment transformation and vertical flux in an area of convergence in the North Atlantic

    Science.gov (United States)

    Head, E. J. H.; Horne, E. P. W.

    Particulate samples from the water column, to depths of 80-120 m, were collected over a 10-day period during a bloom in the North Atlantic, near 37°N, 40°W, between 12 and 22 April 1990. These samples were analysed by HPLC for their chlorin and carotenoid content. The same analysis was carried out for samples of faecal pellets collected from copepods from depths of 0-100 m, which had fed in situ, and for material from sediment traps in the 100-500 m depth range. Water column pigment compositions were consistent with observations that diatoms and Phaeocystis were major components of the bloom. They also sometimes showed high concentrations of chlorophyllide a and a phaephorbide a-like pigment, which may be due to algal die-off and cell autolysis. Faecal pellets contained high concentrations of pyrophaeophorbide a lower amounts of unidentified phaeophorbides and some chlorophyll a, but none of the phaeophorbide a-like pigment found in the water column. Sediment traps contained high concentrations of the phaeophorbides characteristics of copepod faecal pellets and lower, approximately equal amounts of the water column phaeophorbide a-like pigment and chlorophyll a. The sampling area appeared to be in a jet of current, which was moving southwesterly along a front between Eastern Basin Water (to the north) and North Atlantic Central Water (to the south) and which seemed to be drawing in water from both these water masses. Areas of downwelling, thought to be associated with these convergent currents, may have accelerated the sedimentation of dead and dying phytoplankton cells.

  11. Vertical leaf area distribution, light transmittance, and application of the Beer-Lambert Law in four mature hardwood stands in the southern Appalachians

    Science.gov (United States)

    James M. Vose; Neal H. Sullivan; Barton D. Clinton; Paul V. Bolstad

    1995-01-01

    We quantified stand leaf area index and vertical leaf area distribution, and developed canopy extinction coefficients (k), in four mature hardwood stands. Leaf area index, calculated from litter fall and specific leaf area (cm²·g-1), ranged from 4.3 to 5.4 m²·m-2. In three of the four stands, leaf area was distributed in...

  12. Large Area Silicon Carbide Vertical JFETs for 1200 V Cascode Switch Operation

    Directory of Open Access Journals (Sweden)

    Victor Veliadis

    2008-01-01

    Full Text Available SiC VJFETs are excellent candidates for reliable high-power/temperature switching as they only use pn junctions in the active device area where the high-electric fields occur. VJFETs do not suffer from forward voltage degradation, exhibit excellent short-circuit performance, and operate at 300°C. 0.19 cm2 1200 V normally-on and 0.15 cm2 low-voltage normally-off VJFETs were fabricated. The 1200-V VJFET outputs 53 A with a forward drain voltage drop of 2 V and a specific onstate resistance of 5.4 mΩ cm2. The low-voltage VJFET outputs 28 A with a forward drain voltage drop of 3.3 V and a specific onstate resistance of 15 mΩ cm2. The 1200-V SiC VJFET was connected in the cascode configuration with two Si MOSFETs and with a low-voltage SiC VJFET to form normally-off power switches. At a forward drain voltage drop of 2.2 V, the SiC/MOSFETs cascode switch outputs 33 A. The all-SiC cascode switch outputs 24 A at a voltage drop of 4.7 V.

  13. Ensuring safety of people in case of severe floods: feasibility and relevance of vertical evacuation strategies in high population density areas

    Directory of Open Access Journals (Sweden)

    Pannier Rodolphe

    2016-01-01

    Full Text Available When a major flooding event is expected the authorities in charge of the crisis management often consider bringing people to safety by making them leaving temporarily the threatened area before the onset of the flood. This strategy is called “horizontal evacuation”. It has to be distinguished from “vertical evacuation”, which means that people reach a shelter above the wtaer level within the flood area. Vertical evacuation is often the spontaneousbehaviourof people who are surprised by the flood and are trying to reach a tree, a floor upstairs, a roof of a building etc. in order to get away from the rising water. But vertical evacuation could also be consideredas an alternative strategy to horizontal evacuation when moving outside the flood area is neither a faisible nor a relevant option, for example in high-population density areas. In order to be a credible alternative to horizontal evacuation, vertical evacuation has to be carefully planned. This paper aims to explain why horizontal evacuation is not always a suitable option in case of major flood and to explore under what conditions vertical evacuation can be a relevantalternative solution to horizontal evacuation. It also adresses some general recommendations about how to prepare a vertical evacuation strategy..

  14. Swept-Source Optical Coherence Tomographic Findings of Choroidal Osteoma

    Directory of Open Access Journals (Sweden)

    Yuki Hayashi

    2014-07-01

    Full Text Available Purpose: To report the morphologic features of a choroidal osteoma using swept-source optical coherence tomography (SS-OCT and fundus autofluorescence (FAF. Methods: Two eyes of two cases with a choroidal osteoma were studied using SS-OCT and FAF. Results: The location of the tumor was circumpapillary without macular involvement in case 1 and juxtapapillary with macular involvement in case 2. Both cases had a mixture of calcified and decalcified areas, and a concomitant choroidal neovascularization was found in case 2. The FAF images showed decreased autofluorescence in the central decalcified regions and relatively preserved fluorescence in marginal calcified regions in both cases. SS-OCT revealed a normal inner retina and an abnormal outer retina in both cases, and subretinal fluid in case 2. The calcified regions appeared sponge-like and were multilayered in case 2. A lamellar reflective pattern was observed in the decalcified regions in case 1, and hyperreflective mound-like areas were observed in both cases. SS-OCT demonstrated hyperreflective areas above Bruch's membrane accompanied by disruption of Bruch's membrane in case 1. The chorioscleral border was visible in both cases. Conclusions: The FAF pattern in the calcified and decalcified areas of the choroidal osteoma may correspond to the different stage of tumor evolution. The SS-OCT findings indicate that choroidal osteomas can have characteristic reflective patterns and alterations of the overlying retina.

  15. Nox diffusion-simulation in an urban area in using the vertical diffusion diagram including a surface roughness parameter

    Energy Technology Data Exchange (ETDEWEB)

    Kono, Hitoshi; Fujimoto, Akira; Nakano, Hiroshi

    1988-03-31

    In recent years, in order to attain a total quantity regulation of air pollution and to prepare a local air-control program, a diffusion simulation is often made using a Gaussian plume model. NOx diffusion simulation of the urban area was carried out using a vertical diffusion width by taking a parameter of ground-surface roughness using Smith's correction to the Gaussian model. For the diffusion of car exhaust gas, comparison was made for the estimate and the measurement by jointly using the values of ground-surface roughness and the initial diffusion width. As a result, change in the diffusion width of the car exhaust gas due to the urban buildings was expressed at a necessary practical level by giving the height of the point of calculation, 1 - 3 m in the central part and 30 cm at the peripheral part, and giving the initial diffusion width of roughly half to equal size of initial diffusion width to the average height of the buildings. (2 figs, 8 tabs, 20 refs)

  16. Noninvasive Visualization and Analysis of the Human Parafoveal Capillary Network Using Swept Source OCT Optical Microangiography.

    Science.gov (United States)

    Kuehlewein, Laura; Tepelus, Tudor C; An, Lin; Durbin, Mary K; Srinivas, Sowmya; Sadda, Srinivas R

    2015-06-01

    We characterized the foveal avascular zone (FAZ) and the parafoveal capillary network in healthy subjects using swept source OCT optical microangiography (OMAG). We acquired OMAG images of the macula of 19 eyes (13 healthy individuals) using a prototype swept source laser OCT. En face images of the retinal vasculature were generated for superficial and deep inner retinal layers (SRL/DRL) in regions of interest 250 (ROI-250) and 500 (ROI-500) μm from the FAZ border. The mean area (mm2) of the FAZ was 0.304 ± 0.132 for the SRL and 0.486 ± 0.162 for the DRL (P network at different retinal layers.

  17. Steady-state pulses and superradiance in short-wavelength, swept-gain amplifiers

    International Nuclear Information System (INIS)

    Bonifacio, R.; Hopf, F.A.; Meystre, P.; Scully, M.O.

    1975-01-01

    The steady-state behavior of amplifiers in which the excitation is swept at the speed of light is discussed in the semiclassical approximation. In the present work the case where the decay time of the population is comparable to that of the polarization is examined. Pulse propagation is shown to obey a generalized sine-Gordon equation which contains the effects of atomic relaxations. The analytical expression of the steady-state pulses (SSP) gives two threshold conditions. In the region of limited gain the SSP is a broad pulse with small area which can be obtained by small signal theory. In the second region of high gain the SSP is the superradiant π pulse. Its pulse power is not limited as in usual superradiant theory because, as is shown, for a swept excitation the cooperation-length limit does not exist

  18. SAR Interferometry and Precise Leveling for the Determination of Vertical Displacements in the Upper Rhine Graben Area, Southwest Germany

    Science.gov (United States)

    Fuhrmann, T.; Schenk, A.; Westerhaus, M.; Zippelt, K.; Heck, B.

    2013-12-01

    The PS-InSAR (Persistent Scatterer SAR Interferometry) method and precise levelings provide a unique database to detect recent displacements of the Earth's surface. Data of both measurement techniques are analyzed at Geodetic Institute, Karlsruhe Institute of Technology, in order to gain detailed insight into the velocity field of the Upper Rhine Graben (URG). As central and most prominent segment of the European Cenozoic rift system, the seismically and tectonically active Rhine Graben is of steady geo-scientific interest. In the last decades, the URG is characterized by small tectonic movements (Switzerland over the last 100 years building a network of leveling lines. A kinematic network adjustment is applied on the leveling data, providing an accurate solution for vertical displacement rates with accuracies of 0.2 to 0.4 mm/a. The biggest disadvantage of the leveling database is the sparse spatial distribution of the measurement points. Therefore, PS-InSAR is used to significantly increase the number of points within the leveling loops. To obtain a high accuracy for line of sight displacement rates, ERS-1/2 and Envisat data from ascending and descending orbits covering a period from 1992 to 2000 and 2002 to 2010, resp., are processed using StaMPS (Stanford Method for Persistent Scatterers). As the tectonic displacements cover a large area, the separation of atmospheric effects and orbit errors plays an important role in the PS-InSAR processing chain. Besides the tectonic signal, man-induced surface displacements caused by oil extraction are investigated. A comparison between the estimates from leveling and InSAR provides detailed insight into the temporal and spatial characteristics of the surface displacement as well as into the possibilities and limits of the measurement techniques.

  19. Functional swept source optical coherence tomography

    International Nuclear Information System (INIS)

    Blatter, C.

    2013-01-01

    Optical coherence tomography (OCT) is a non-invasive imaging modality capable of providing information about a sample structure along the three spatial dimensions with micrometer scale resolution. A new chapter opened with the development of functional OCT that provides additional information to the standard structural imaging. Among those extensions is Doppler OCT (D-OCT) that yields knowledge about the motion of the sample and/or its substructure. Its main application in biomedical imaging is the assessment of blood flow. D-OCT is therefore often associated with blood velocity measurement and recently with the visualization of the vascular network. Blood flow and vasculature are important markers of tissue health. Their assessment provides crucial information for diagnostics, treatment planning and monitoring. OCT is in a good position, as a non-invasive technique, to become an alternative to current fluorescence based techniques, allowing thereby also more frequent examination and broader screenings and, as a high resolution modality, to give insight into potential changes at the capillary level. An important challenge of in vivo imaging is patient motion that decreases the quality of acquisitions. One solution to that issue is high-speed imaging. Recently swept source OCT (SSOCT) revealed to be an efficient technology to achieve high-speed. This thesis investigates the use of swept sources for qualitative and quantitative vasculature imaging. It is presented via five journal papers that form its backbone. Prior to that, main concepts of FDOCT, D-OCT and SS systems are presented. The first paper reports a SSOCT system for skin imaging. In standard OCT systems, improving the lateral resolution comes at a cost of reduced depth of focus. This should be avoided in order to be able to assess different vascular beds in depth while keeping the speed advantage of FDOCT. Employing a Bessel beam for illumination of the sample allows circumventing this issue. The image

  20. Analysis of conditions favourable for small vertical axis wind turbines between building passages in urban areas of Sweden

    Science.gov (United States)

    Awan, Muhammad Rizwan; Riaz, Fahid; Nabi, Zahid

    2017-05-01

    This paper presents the analysis of installing the vertical axis wind turbines between the building passages on an island in Stockholm, Sweden. Based on the idea of wind speed amplification due to the venture effect in passages, practical measurements were carried out to study the wind profile for a range of passage widths in parallel building passages. Highest increment in wind speed was observed in building passages located on the periphery of sland as wind enters from free field. Wind mapping was performed in the island to choose the most favourable location to install the vertical axis wind turbines (VAWT). Using the annual wind speed data for location and measured amplification factor, energy potential of the street was calculated. This analysis verified that small vertical axis wind turbines can be installed in the passage centre line provided that enough space is provided for traffic and passengers.

  1. Vertical-cavity surface-emitting lasers for medical diagnosis

    DEFF Research Database (Denmark)

    Ansbæk, Thor

    This thesis deals with the design and fabrication of tunable Vertical-Cavity Surface-Emitting Lasers (VCSELs). The focus has been the application of tunable VCSELs in medical diagnostics, specifically OCT. VCSELs are candidates as light sources for swept-source OCT where their high sweep rate, wide...

  2. Effect of Cover Crops on Vertical Distribution of Leaf Area and Dry Matter of Soybean (Glycine max L. in Competition with Weeds

    Directory of Open Access Journals (Sweden)

    seyyedeh samaneh hashemi

    2017-08-01

    Full Text Available Introduction Amount and vertical distribution of leaf area are essential for estimating interception and utilization of solar radiation of crop canopies and, consequently dry matter accumulation (Valentinuz & Tollenaar, 2006. Vertical distribution of leaf area is leaf areas per horizontal layers, based on height (Boedhram et al., 2001. Above-ground biomass is one of the central traits in functional plant ecology and growth analysis. It is a key parameter in many allometric relationships (Niklas & Enquist, 2002. The vertical biomass distribution is considered to be the main determinant of competitive strength in plant species. The presence of weeds intensifies competition for light, with the effect being determined by plant height, position of the branches, and location of the maximum leaf area. So, this experiment was conducted to study the vertical distribution of leaf area and dry matter of soybean canopy in competition with weeds and cover crops. Materials and methods This experiment was performed based on complete randomized block design with 3 replications in center of Agriculture of Joybar in 2013. Soybean was considered as main crop and soybean and Persian clover (Trifolium resupinatum L., fenugreek (Trigonella foenum–graecum L., chickling pea (Lathyrus sativus L. and winter vetch (Vicia sativa L. were the cover crops. Treatments were included cover crops (Persian clover, fenugreek, chickling pea and winter vetch and cover crop planting times (simultaneous planting of soybean with cover crops and planting cover crops three weeks after planting of soybeans and also monoculture of soybeans both in weedy and weed free conditions were considered as controls. Soybean planted in 50 cm row spacing with 5 cm between plants in the same row. Each plot was included 5 rows soybeans. Cover crop inter-seeded simultaneously in the main crop. Crops were planted on 19 May 2013 for simultaneous planting of soybean. The dominant weed species were green

  3. Implementation of vertical multistage centrifugal pump system for villages at an altitude of ± 1200m above sea level in Sipahutar - North Sumatera area

    Science.gov (United States)

    Parde de, Marincan; Simangunsong, Riyanto; Hedwig, Rinda

    2017-12-01

    Clean water supply is rare in most villages at an altitude of ±1200m above the sea level in North Sumatera due to the topography of the village. The idea to help villagers fulfilling their basic needs in the situation makes this research important. Many experiments had been done previously, such as implementing drilled well but none was successful until we developed a vertical multistage centrifugal pump system. The natural water spring in the area targeted was found in 86 meters depth and would be distributed as far as 500m with area of 1.5km2 from the water tank. The main problem happened was the electric supplies which was always lower than it was expected in that area. Therefore, the successful of the system was happily accepted by the villagers and this research is highly expected to be developed and implemented to other villages, not only in Sipahutar area but also in all Tarutung area.

  4. SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY REVEALS INTERNAL LIMITING MEMBRANE PEELING ALTERS DEEP RETINAL VASCULATURE.

    Science.gov (United States)

    Michalewska, Zofia; Nawrocki, Jerzy

    2018-04-30

    To describe morphology of retinal and choroidal vessels in swept-source optical coherence tomography angiography before and after vitrectomy with the temporal inverted internal limiting membrane (ILM) flap technique for full-thickness macular holes. Prospective, observational study of 36 eyes of 33 patients with full-thickness macular holes swept-source optical coherence tomography angiography was performed in patients before and 1 month after vitrectomy. Vitrectomy with the temporal inverted ILM flap technique was performed. In this method, ILM is peeled only at one side of the fovea. An ILM flap is created to cover the macular hole. Comparison of retina vasculature in the areas of ILM peeling vs. no ILM peeling at 1 and 3 months after successful vitrectomy was performed. The study demonstrated lower density of vessels in the deep retinal plexus in the area where ILM was peeled as compared to the rest of the fovea. Visual acuity and central retinal thickness 1 month after surgery correlates with fovea avascular zone diameter in deep retinal layers at the same time point (P = 0.001). This study confirmed that ILM peeling might alter blood flow in deep retinal vessels below the peeling area in the early postoperative period. The area of the fovea avascular zone corresponds to functional results at the same time point.

  5. Confocal Microscopy for Process Monitoring and Wide-Area Height Determination of Vertically-Aligned Carbon Nanotube Forests

    Directory of Open Access Journals (Sweden)

    Markus Piwko

    2015-08-01

    Full Text Available Confocal microscopy is introduced as a new and generally applicable method for the characterization of the vertically-aligned carbon nanotubes (VACNT forest height. With this technique process control is significantly intensified. The topography of the substrate and VACNT can be mapped with a height resolution down to 15 nm. The advantages of confocal microscopy, compared to scanning electron microscopy (SEM, are demonstrated by investigating the growth kinetics of VACNT using Al2O3 buffer layers with varying thicknesses. A process optimization using confocal microscopy for fast VACNT forest height evaluation is presented.

  6. Vertically-resolved particle size distribution within and above the mixing layer over the Milan metropolitan area

    Directory of Open Access Journals (Sweden)

    L. Ferrero

    2010-04-01

    Full Text Available Vertical aerosol profiles were directly measured over the city of Milan during three years (2005–2008 of field campaigns. An optical particle counter, a portable meteorological station and a miniaturized cascade impactor were deployed on a tethered balloon. More than 300 vertical profiles were measured, both in winter and summer, mainly in conditions of clear, dry skies.

    The mixing height was determined from the observed vertical aerosol concentration gradient, and from potential temperature and relative humidity profiles. Results show that inter-consistent mixing heights can be retrieved highlighting good correlations between particle dispersion in the atmosphere and meteorological parameters. Mixing height growth speed was calculated for both winter and summer showing the low potential atmospheric dispersion in winter.

    Aerosol number size distribution and chemical composition profiles allowed us to investigate particle behaviour along height. Aerosol measurements showed changes in size distribution according to mixing height. Coarse particle profiles (dp>1.6 μm were distributed differently than the fine ones (dp<1.6 μm were, at different heights of the mixing layer. The sedimentation process influenced the coarse particle profiles, and led to a reduction in mean particle diameter for those particles observed by comparing data above the mixing height with ground data (−14.9±0.6% in winter and −10.7±1.0% in summer. Conversely, the mean particle diameter of fine particles increased above the mixing height under stable atmospheric conditions; the average increase, observed by comparing data above the mixing height with ground data, was +2.1±0.1% in winter and +3.9±0.3% in summer. A hierarchical statistical model was created to describe the changes in the size distribution of fine particles along height. The proposed model can be used to estimate the typical vertical

  7. Localisation of nursery areas based on comparative analyses of the horizontal and vertical distribution patterns of juvenile Baltic cod (Gadus morhua)

    DEFF Research Database (Denmark)

    Nielsen, J. Rasmus; Lundgren, Bo; Kristensen, Kasper

    2013-01-01

    Baltic cod are determined, and their nursery areas are localised according to the environmental factors affecting them. Comparative statistical analyses of biological, hydrographic and hydroacoustic data are carried out based on standard ICES demersal trawl surveys and special integrated trawl...... and acoustic research surveys. Horizontal distribution maps for the 2001–2010 cohorts of juvenile cod are further generated by applying a statistical log-Gaussian Cox process model to the standard trawl survey data. The analyses indicate size-dependent horizontal and distinct vertical and diurnal distribution...... in deep sea localities down to a 100 m depth and at oxygen concentrations between 2–4 ml O2.l−1. The vertical, diurnally stratified and repeated trawling and hydroacoustic target strength-depth distributions obtained from the special surveys show juvenile cod concentrations in frontal zone water layers...

  8. Vertical and Horizontal Measurements of Ambient Ozone over a Gas and Oil Production Area using a UAV Platform

    Science.gov (United States)

    Jensen, A.; Gowing, I.; Martin, R. S.

    2013-12-01

    During the 2013 wintertime Uintah Basin Ozone Study (UBOS13), an autonomous unmanned aerial vehicle (UAV) platform, coupled with an on-board UV ozone monitor, flew several spatial profiles near the location (Horse Pool) of other concentrated measurements by other co-investigators. The airframe, part of the Utah Water Research Laboratory's (UWRL) AggieAir UAV program, consisted of a custom-built, battery-operated plane with and 2.4 m (8 ft) wing span and a 12.7 cm x 12.7 cm x 30.5 cm payload bay with a carrying capacity of approximately 2.0 kg. With the current power system, the fully-loaded AggieAir UAV can fly for approximately 45 minutes at a nominal airspeed of 13.4 m/s (30 mph). The system can be operated either in manual control or be flown autonomously following preprogrammed waypoints via a built in GPS system. The AggieAir UAV systems were primarily designed for photographic and telemetry tracking projects. For the UBOS13 flights, a 2B Technologies Model 205 Ozone (O3) monitor was modified for minimal weight optimization, wrapped with lightweight insulation and secured into the UAV payload bay. Additionally, HOBO Model H08-001-02 shielded temperature/datalogger was secured to the exterior of the UAV from parallel thermal profile determination. During the study period, three demonstration flight profiles were obtained on February 17 and 18, 2013: two vertical 'curtain' profiles and a pair of 'stacked' horizontal profiles. As recorded by numerous ground-based monitoring sites, the ozone during the UAV test periods was characterized by initial trends of daytime O3 maximums over 130 ppb, followed by a meteorological front partially ventilating the Basin on the evening of Feb. 17th leading to decreased O3 minimums around 40 ppb. However, the ground level O3 rebuilt quickly to ground level maximums approaching 100 ppb. The vertical 'curtain' flown on the evening of Feb. 17th only reached a maximum elevation of about 2160 m ASL (600 m AGL) due to encountering

  9. Aerodynamic Classification of Swept-Wing Ice Accretion

    Science.gov (United States)

    Diebold, Jeff M.; Broeren, Andy P.; Bragg, Michael B.

    2013-01-01

    The continued design, certification and safe operation of swept-wing airplanes in icing conditions rely on the advancement of computational and experimental simulation methods for higher fidelity results over an increasing range of aircraft configurations and performance, and icing conditions. The current stateof- the-art in icing aerodynamics is mainly built upon a comprehensive understanding of two-dimensional geometries that does not currently exist for fundamentally three-dimensional geometries such as swept wings. The purpose of this report is to describe what is known of iced-swept-wing aerodynamics and to identify the type of research that is required to improve the current understanding. Following the method used in a previous review of iced-airfoil aerodynamics, this report proposes a classification of swept-wing ice accretion into four groups based upon unique flowfield attributes. These four groups are: ice roughness, horn ice, streamwise ice and spanwise-ridge ice. In the case of horn ice it is shown that a further subclassification of "nominally 3D" or "highly 3D" horn ice may be necessary. For all of the proposed ice-shape classifications, relatively little is known about the three-dimensional flowfield and even less about the effect of Reynolds number and Mach number on these flowfields. The classifications and supporting data presented in this report can serve as a starting point as new research explores swept-wing aerodynamics with ice shapes. As further results are available, it is expected that these classifications will need to be updated and revised.

  10. Investigation of one-dimensional interfacial area transport for vertical upward air–water two-phase flow in an annular channel at elevated pressures

    International Nuclear Information System (INIS)

    Ozar, B.; Brooks, C.S.; Euh, D.J.; Hibiki, T.; Ishii, M.

    2013-01-01

    Highlights: • Interfacial area transport equation (IATE) for a rectangular duct is modified for an annulus. • IATE predicts interfacial area transport in bubbly-to-churn flow. • Scalability of IATE to elevated pressure conditions is validated. • Detailed 1D interfacial area transport data are presented. • Detailed interfacial area transport mechanisms are discussed. -- Abstract: The interfacial area transport of vertical, upward, air–water two-phase flows in an annular channel has been investigated at different system pressures. The inner and outer diameters of the annular channel were 19.1 mm and 38.1 mm, respectively. Twenty three inlet flow conditions were selected, which covered bubbly, cap-bubbly, and churn-turbulent flows. These flow conditions also overlapped with twelve conditions of a previous study for comparison. The local flow parameters, such as void fractions, interfacial area concentrations (IAC), and bubble interface velocities, were measured at nine radial positions for the three axial locations and converted into area-averaged parameters. The axial evolutions of local flow structure were interpreted in terms of bubble coalescence, breakup, expansion of the gas-phase due to pressure drop and system pressure. An assessment of interfacial area transport equation (IATE) was made and compared with the experimental data. A discussion of the comparison between model prediction and the experimental results were made

  11. Investigation of one-dimensional interfacial area transport for vertical upward air–water two-phase flow in an annular channel at elevated pressures

    Energy Technology Data Exchange (ETDEWEB)

    Ozar, B., E-mail: ozar@fauske.com [School of Nuclear Engineering, Purdue University, 400 Central Drive, West Lafayette, IN 47907-2017 (United States); Brooks, C.S. [School of Nuclear Engineering, Purdue University, 400 Central Drive, West Lafayette, IN 47907-2017 (United States); Euh, D.J. [Korea Atomic Energy Research Institute, 150 Deokjin, Yuseong, Daejeon 305-353 (Korea, Republic of); Hibiki, T.; Ishii, M. [School of Nuclear Engineering, Purdue University, 400 Central Drive, West Lafayette, IN 47907-2017 (United States)

    2013-10-15

    Highlights: • Interfacial area transport equation (IATE) for a rectangular duct is modified for an annulus. • IATE predicts interfacial area transport in bubbly-to-churn flow. • Scalability of IATE to elevated pressure conditions is validated. • Detailed 1D interfacial area transport data are presented. • Detailed interfacial area transport mechanisms are discussed. -- Abstract: The interfacial area transport of vertical, upward, air–water two-phase flows in an annular channel has been investigated at different system pressures. The inner and outer diameters of the annular channel were 19.1 mm and 38.1 mm, respectively. Twenty three inlet flow conditions were selected, which covered bubbly, cap-bubbly, and churn-turbulent flows. These flow conditions also overlapped with twelve conditions of a previous study for comparison. The local flow parameters, such as void fractions, interfacial area concentrations (IAC), and bubble interface velocities, were measured at nine radial positions for the three axial locations and converted into area-averaged parameters. The axial evolutions of local flow structure were interpreted in terms of bubble coalescence, breakup, expansion of the gas-phase due to pressure drop and system pressure. An assessment of interfacial area transport equation (IATE) was made and compared with the experimental data. A discussion of the comparison between model prediction and the experimental results were made.

  12. Comments on Frequency Swept Rotating Input Perturbation Techniques and Identification of the Fluid Force Models in Rotor/bearing/seal Systems and Fluid Handling Machines

    Science.gov (United States)

    Muszynska, Agnes; Bently, Donald E.

    1991-01-01

    Perturbation techniques used for identification of rotating system dynamic characteristics are described. A comparison between two periodic frequency-swept perturbation methods applied in identification of fluid forces of rotating machines is presented. The description of the fluid force model identified by inputting circular periodic frequency-swept force is given. This model is based on the existence and strength of the circumferential flow, most often generated by the shaft rotation. The application of the fluid force model in rotor dynamic analysis is presented. It is shown that the rotor stability is an entire rotating system property. Some areas for further research are discussed.

  13. Vertical pump assembly

    International Nuclear Information System (INIS)

    Dohnal, M.; Rosel, J.; Skarka, V.

    1988-01-01

    The mounting is described of the drive assembly of a vertical pump for nuclear power plants in areas with seismic risk. The assembly is attached to the building floor using flexible and damping elements. The design allows producing seismically resistant pumps without major design changes in the existing types of vertical pumps. (E.S.). 1 fig

  14. Aeroelastic behavior of composite rotor blades with swept tips

    Science.gov (United States)

    Yuan, Kuo-An; Friedmann, Peretz P.; Venkatesan, Comandur

    1992-01-01

    This paper presents an analytical study of the aeroelastic behavior of composite rotor blades with straight and swept tips. The blade is modeled by beam type finite elements. A single finite element is used to model the swept tip. The nonlinear equations of motion for the finite element model are derived using Hamilton's principle and based on a moderate deflection theory and accounts for: arbitrary cross-sectional shape, pretwist, generally anisotropic material behavior, transverse shears and out-of-plane warping. Numerical results illustrating the effects of tip sweep, anhedral and composite ply orientation on blade aeroelastic behavior are presented. It is shown that composite ply orientation has a substantial effect on blade stability. At low thrust conditions, certain ply orientations can cause instability in the lag mode. The flap-torsion coupling associated with tip sweep can also induce aeroelastic instability in the blade. This instability can be removed by appropriate ply orientation in the composite construction.

  15. Two-year follow-up of changes in bite force and occlusal contact area after intraoral vertical ramus osteotomy with and without Le Fort I osteotomy.

    Science.gov (United States)

    Choi, Y J; Lim, H; Chung, C J; Park, K H; Kim, K H

    2014-06-01

    This study was performed to examine the longitudinal changes in bite force and occlusal contact area after mandibular setback surgery via intraoral vertical ramus osteotomy (IVRO). Patients with mandibular prognathism who underwent IVRO (surgical group: 39 men and 39 women) were compared with subjects with class I skeletal and dental relationships (control group; 32 men and 35 women). The surgical group was divided into two subgroups: 1-jaw surgery (n = 30) and 2-jaw surgery (n = 48). Bite force and contact area were measured in maximum intercuspation with the Dental Prescale System before treatment, within 1 month before surgery, and at 1, 3, 6, 9, 12, and 24 months postsurgery. A linear mixed model was used to investigate the time-dependent changes and associated factors. Bite force and contact area decreased during presurgical orthodontic treatment, were minimal at 1 month postsurgery, and increased gradually thereafter. The 1-jaw and 2-jaw subgroups showed no significant differences in bite force. The time-dependent changes in bite force were significantly different according to the contact area (P contact area gradually increase throughout the postsurgical evaluation period. Increasing the occlusal contact area may be essential for improving bite force after surgery. Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  16. Investigation the Vertical Distribution of Leaf Area and Dry Matter of Sweet Basil (Ocimum basilicum L., Borage (Borago officinalis L. and Cover Crops in Competition with Weeds

    Directory of Open Access Journals (Sweden)

    zeinab shirzadi margavi

    2017-10-01

    Full Text Available Introduction Distribution of leaf area and dry matter are the effective factors that influence on absorption the radiation, evaporation and transpiration of canopy and eventually dry matter accumulation and grain yield in plants. Plant canopy is the spatial arrangement of shoots in a plant population. In plant canopy, leaves are responsible for radiation absorption and gas exchange with the outside. Stem and branches arrange photosynthetic organs somehow, which gas exchange and light distribution best done. The effect of canopy structure on gas exchange and absorption of radiation in plant communities caused detailed study of the canopy structure to be more important. Materials and methods In order to investigate the vertical distribution of leaf area and dry matter of borage and sweet basil in competition with weeds by cover crops treatments, a field experiment was carried out in a randomized complete block design with 8 treatments and 3 replications in Agricultural Sciences and Natural Resources University of Sari in 2013. Treatments were cover crops mung bean (Vigna radiata L. and Persian clover (Trifolium resupinatum L. in the rows between the sweet basil (Ocimum basilicum L. and borage (Borago officinalis L.. Moreover, in order to evaluate the effectiveness of cover crops to control weeds, pure stand of sweet basil and borage in terms of weeding and no weed controls per replicates were used. Each plot was included 5 rows of medicinal plants. Cover crop inter-seeded simultaneously in the main crop. Estimation of leaf area and dry matter of each plant in different canopy layers (0-20, 20-40, 40-60, 80.100, 100-120 and 120-140 cm were done after 75 planting days, with 1 m × 1 m quadrate per plot. For this purpose a vertical card board frame marked in 20-cm increments was used in the field as a guide to cut standing plants (crops, cover crops and weeds into 20-cm strata increments (Mosier & Oliver, 1995. All samples were transferred to the

  17. Development of a Vertical Recirculation Well System for the A/M Area of the Savannah River Site

    International Nuclear Information System (INIS)

    Jackson, D.G. Jr.; Looney, B.B.

    1996-01-01

    The objective of this work is to examine and develop a remediation scenario to provide long term hydraulic control and remediation of the dissolved chlorinated solvent plume within the Western and Southern Sectors of the A/M Area. This scope includes the development and siting of a remediation system that will contain the 500 part per billion trichloroethylene isoconcentration contour within each sector

  18. A Geometrical-based Vertical Gain Correction for Signal Strength Prediction of Downtilted Base Station Antennas in Urban Areas

    DEFF Research Database (Denmark)

    Rodriguez, Ignacio; Nguyen, Huan Cong; Sørensen, Troels Bundgaard

    2012-01-01

    -based extension to standard empirical path loss prediction models can give quite reasonable accuracy in predicting the signal strength from tilted base station antennas in small urban macro-cells. Our evaluation is based on measurements on several sectors in a 2.6 GHz Long Term Evolution (LTE) cellular network......, with electrical antenna downtilt in the range from 0 to 10 degrees, as well as predictions based on ray-tracing and 3D building databases covering the measurement area. Although the calibrated ray-tracing predictions are highly accurate compared with the measured data, the combined LOS/NLOS COST-WI model...

  19. 1.9 W continuous-wave single transverse mode emission from 1060 nm edge-emitting lasers with vertically extended lasing area

    Energy Technology Data Exchange (ETDEWEB)

    Miah, M. J., E-mail: jarez.miah@tu-berlin.de; Posilovic, K.; Kalosha, V. P.; Rosales, R.; Bimberg, D. [Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Kettler, T. [Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); PBC Lasers GmbH, Hardenbergstr. 36, 10623 Berlin (Germany); Skoczowsky, D. [PBC Lasers GmbH, Hardenbergstr. 36, 10623 Berlin (Germany); Pohl, J.; Weyers, M. [Ferdinand-Braun-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin (Germany)

    2014-10-13

    High-brightness edge-emitting semiconductor lasers having a vertically extended waveguide structure emitting in the 1060 nm range are investigated. Ridge waveguide (RW) lasers with 9 μm stripe width and 2.64 mm cavity length yield highest to date single transverse mode output power for RW lasers in the 1060 nm range. The lasers provide 1.9 W single transverse mode optical power under continuous-wave (cw) operation with narrow beam divergences of 9° in lateral and 14° (full width at half maximum) in vertical direction. The beam quality factor M{sup 2} is less than 1.9 up to 1.9 W optical power. A maximum brightness of 72 MWcm{sup −2}sr{sup −1} is obtained. 100 μm wide and 3 mm long unpassivated broad area lasers provide more than 9 W optical power in cw operation.

  20. Vertical and horizontal distribution of radionuclides ({sup 232}Th, {sup 238}U and {sup 40}K) in sediment from Manjung coastal water area Perak, Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, Anisa, E-mail: coppering@ymail.com; Hamzah, Zaini; Wood, Ab. Khalik [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450, Shah Alam, Selangor (Malaysia); Saat, Ahmad [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450, Shah Alam, Selangor (Malaysia); Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)

    2016-01-22

    Distribution of radionuclides from anthropogenic activities has been widely studied in marine coastal area. Due to rapid population growth and socio-economic development in Manjung area such as coal fired power plant, iron foundries, port development, waste discharged from factories and agriculture runoff may contribute to increase in pollution rate. The radioactive materials from anthropogenic activities could deteriorate the quality of the marine ecosystem and thus lead to possible radiological health risk to the population. Radionuclides ({sup 232}Th, {sup 238}U and {sup 40}K) content in surface and profile sediment from Manjung coastal area was determined in this study. Radionuclides in sediment from seven locations were collected using sediment core sampling and measurements were carried out using Energy Dispersive X-ray Fluorescence (EDXRF) spectroscopy. The results show that the concentration of radionuclides in surface sediment and distribution trend of depth vertical profile sediment generally varies depending on locations. Enrichment factors (EF), geo-accumulation index (I{sub geo}) and pollution index (PI) were applied to determine level of pollution of this study area. The radiological risks related to human exposure were evaluated based on external hazard index (H{sub ex})

  1. Vertical and horizontal distribution of radionuclides (232Th, 238U and 40K) in sediment from Manjung coastal water area Perak, Malaysia

    Science.gov (United States)

    Abdullah, Anisa; Hamzah, Zaini; Saat, Ahmad; Wood, Ab. Khalik

    2016-01-01

    Distribution of radionuclides from anthropogenic activities has been widely studied in marine coastal area. Due to rapid population growth and socio-economic development in Manjung area such as coal fired power plant, iron foundries, port development, waste discharged from factories and agriculture runoff may contribute to increase in pollution rate. The radioactive materials from anthropogenic activities could deteriorate the quality of the marine ecosystem and thus lead to possible radiological health risk to the population. Radionuclides (232Th, 238U and 40K) content in surface and profile sediment from Manjung coastal area was determined in this study. Radionuclides in sediment from seven locations were collected using sediment core sampling and measurements were carried out using Energy Dispersive X-ray Fluorescence (EDXRF) spectroscopy. The results show that the concentration of radionuclides in surface sediment and distribution trend of depth vertical profile sediment generally varies depending on locations. Enrichment factors (EF), geo-accumulation index (Igeo) and pollution index (PI) were applied to determine level of pollution of this study area. The radiological risks related to human exposure were evaluated based on external hazard index (Hex).

  2. Vertical and horizontal distribution of radionuclides (232Th, 238U and 40K) in sediment from Manjung coastal water area Perak, Malaysia

    International Nuclear Information System (INIS)

    Abdullah, Anisa; Hamzah, Zaini; Wood, Ab. Khalik; Saat, Ahmad

    2016-01-01

    Distribution of radionuclides from anthropogenic activities has been widely studied in marine coastal area. Due to rapid population growth and socio-economic development in Manjung area such as coal fired power plant, iron foundries, port development, waste discharged from factories and agriculture runoff may contribute to increase in pollution rate. The radioactive materials from anthropogenic activities could deteriorate the quality of the marine ecosystem and thus lead to possible radiological health risk to the population. Radionuclides ( 232 Th, 238 U and 40 K) content in surface and profile sediment from Manjung coastal area was determined in this study. Radionuclides in sediment from seven locations were collected using sediment core sampling and measurements were carried out using Energy Dispersive X-ray Fluorescence (EDXRF) spectroscopy. The results show that the concentration of radionuclides in surface sediment and distribution trend of depth vertical profile sediment generally varies depending on locations. Enrichment factors (EF), geo-accumulation index (I geo ) and pollution index (PI) were applied to determine level of pollution of this study area. The radiological risks related to human exposure were evaluated based on external hazard index (H ex )

  3. An Aerodynamic Investigation of a Forward Swept Wing

    Science.gov (United States)

    1977-12-01

    attached flow at higher angles of attack. 59 -. - . -- ~II The use of winglets should-also be considered to determine their effect on the aerodynamic ...INVSTGAIO OF A" ’/7AI/A/A7D1 ¾~nnt ¾ý’i ~~~)a al -A ApprovedYA~I forSIATO OFli Aees;dsrbuinulmtd AFIT/GAE/AA/77D -4 .1 AN AERODYNAMIC INVESTIGATION OF A...this study was to experimentally and analytically determine certain aerodynamic characteristics of a recently proposed high subsonic, forward swept wing

  4. Study of Swept Angle Effects on Grid Fins Aerodynamics Performance

    Science.gov (United States)

    Faza, G. A.; Fadillah, H.; Silitonga, F. Y.; Agoes Moelyadi, Mochamad

    2018-04-01

    Grid fin is an aerodynamic control surface that usually used on missiles and rockets. In the recent several years many researches have conducted to develop a more efficient grid fins. There are many possibilities of geometric combination could be done to improve aerodynamics characteristic of a grid fin. This paper will only discuss about the aerodynamics characteristics of grid fins compared by another grid fins with different swept angle. The methodology that used to compare the aerodynamics is Computational Fluid Dynamics (CFD). The result of this paper might be used for future studies to answer our former question or as a reference for related studies.

  5. Vertical integration

    International Nuclear Information System (INIS)

    Antill, N.

    1999-01-01

    This paper focuses on the trend in international energy companies towards vertical integration in the gas chain from wellhead to power generation, horizontal integration in refining and marketing businesses, and the search for larger projects with lower upstream costs. The shape of the petroleum industry in the next millennium, the creation of super-major oil companies, and the relationship between size and risk are discussed. The dynamics of vertical integration, present events and future developments are considered. (UK)

  6. Clinical Factors Associated with Lamina Cribrosa Thickness in Patients with Glaucoma, as Measured with Swept Source Optical Coherence Tomography.

    Directory of Open Access Journals (Sweden)

    Kazuko Omodaka

    Full Text Available To investigate the influence of various risk factors on thinning of the lamina cribrosa (LC, as measured with swept-source optical coherence tomography (SS-OCT; Topcon.This retrospective study comprised 150 eyes of 150 patients: 22 normal subjects, 28 preperimetric glaucoma (PPG patients, and 100 open-angle glaucoma patients. Average LC thickness was determined in a 3 x 3 mm cube scan of the optic disc, over which a 4 x 4 grid of 16 points was superimposed (interpoint distance: 175 μm, centered on the circular Bruch's membrane opening. The borders of the LC were defined as the visible limits of the LC pores. The correlation of LC thickness with Humphrey field analyzer-measured mean deviation (MD; SITA standard 24-2, circumpapillary retinal nerve fiber layer thickness (cpRNFLT, the vertical cup-to-disc (C/D ratio, and tissue mean blur rate (MBR was determined with Spearman's rank correlation coefficient. The relationship of LC thickness with age, axial length, intraocular pressure (IOP, MD, the vertical C/D ratio, central corneal thickness (CCT, and tissue MBR was determined with multiple regression analysis. Average LC thickness and the correlation between LC thickness and MD were compared in patients with the glaucomatous enlargement (GE optic disc type and those with non-GE disc types, as classified with Nicolela's method.We found that average LC thickness in the 16 grid points was significantly associated with overall LC thickness (r = 0.77, P < 0.001. The measurement time for this area was 12.4 ± 2.4 minutes. Average LC thickness in this area had a correlation coefficient of 0.57 with cpRNFLT (P < 0.001 and 0.46 (P < 0.001 with MD. Average LC thickness differed significantly between the groups (normal: 268 ± 23 μm, PPG: 248 ± 13 μm, OAG: 233 ± 20 μm. Multiple regression analysis showed that MD (β = 0.29, P = 0.013, vertical C/D ratio (β = -0.25, P = 0.020 and tissue MBR (β = 0.20, P = 0.034 were independent variables significantly

  7. DESIGN OF BACKWARD SWEPT TURBINE WHEEL FOR CRYOGENIC TURBOEXPANDER

    Directory of Open Access Journals (Sweden)

    BALAJI K. CHOUDHURY

    2014-08-01

    Full Text Available With support from the Department of Atomic Energy, our institute has initiated a programme on development and study of a low capacity (20 liters/hr. turboexpander based Nitrogen liquefier. Hence a process design was carried out and a turboexpander was designed to meet the requirement of the liquefier. The turboexpander is used for lowering the temperature of the process gas (Nitrogen by the isenthalpic expansion. The efficiency of the turboexpander mainly depends on the specific speed and specific diameter of the turbine wheel. The paper explains a general methodology for the design of any type of turbine wheel (radial, backward swept and forward swept for any pressure ratio with different process gases. The design of turbine wheel includes the determination of dimensions, blade profile and velocity triangles at inlet and outlet of the turbine wheel. Generally radial turbine wheels are used but in this case to achieve the high efficiency at desired speed, backward curved blades are used to maintain the Mach number of the process gas at the nozzle exit, close to unity. If the velocity of fluid exceeds the speed of sound, the flow gets choked leading to the creation of shock waves and flow at the exit of the nozzle will be non-isentropic.

  8. Development of advanced stability theory suction prediction techniques for laminar flow control. [on swept wings

    Science.gov (United States)

    Srokowski, A. J.

    1978-01-01

    The problem of obtaining accurate estimates of suction requirements on swept laminar flow control wings was discussed. A fast accurate computer code developed to predict suction requirements by integrating disturbance amplification rates was described. Assumptions and approximations used in the present computer code are examined in light of flow conditions on the swept wing which may limit their validity.

  9. The use of the swept area method for assessing the seabob shrimp Xiphopenaeus kroyeri (Heller, 1862 biomass and removal rates based on artisanal fishery-derived data in southern Brazil: using depletion models to reduce uncertainty El uso del método de area de barrido para la evaluación de la biomasa y tasas de remoción del camarón Xiphopenaeus kroyeri (Heller, 1862 a partir de datos de la pesca artesanal en el sur de Brasil: la utilización de modelos de reducción de stock para disminuir incertidumbres

    Directory of Open Access Journals (Sweden)

    Paulo R Pezzuto

    2008-01-01

    Full Text Available The seabob shrimp (Xiphopenaeus kroyeri represents an important fishing resource for artisanal fishermen in coastal areas of southern Brazil. Stock assessments of this species ha ve generally relied on biomass dynamics models as applied to CPUE time-series, which (a are only available for a small offshore fraction of the exploited population and (b does not comprise patterns of the shallowest artisanal fishing grounds. This work explores the use of extensive catch and effort data derived from a small-scale trawl fishery to obtain swept-area estimates of abundance and removal rates in a limited coastal area of southern Brazil (Tijucas Bay, Santa Catarina State, 27°15'S-48°33'W. Data were obtained from 7,198 fishing trips monitored at the fishing communities between June 2004 and August 2005. Because three parameters of the swept-area equation (i.e. trawl velocity, catch efficiency and wing spread were unknown, they were defined through a stochastic procedure and calibrated by estimates produced by a Leslie depletion model applied to concurrent catches obtained in one fishing ground. A 21.7% removal rate was estimated for the period June 2004-January 2005; this increased to nearly 34% between February and July 2005. This removal scenario predicted that a five-month fishery would suffice to remo ve 90% of the biomass available in the Tijucas Bay, nearing the 87% CPUE reduction observed in the same period. Whereas abundance and harvest rate estimates were likely affected by inadequate knowledge of the swept-area equation parameters, the similarity of these estimates with relative abundance indexes supports the convenience of the proposed method and justifies future efforts to improve its accuracy.El camarón (Xiphopenaeus kroyeri representa un importante recurso para pescadores artesanales en areas costeras del sur de Brasil. Evaluaciones de stock de esta especie generalmente resultan de modelos de dinámica de biomasa aplicados a series

  10. Ultrahigh speed endoscopic swept source optical coherence tomography using a VCSEL light source and micromotor catheter

    Science.gov (United States)

    Tsai, Tsung-Han; Ahsen, Osman O.; Lee, Hsiang-Chieh; Liang, Kaicheng; Giacomelli, Michael G.; Potsaid, Benjamin M.; Tao, Yuankai K.; Jayaraman, Vijaysekhar; Kraus, Martin F.; Hornegger, Joachim; Figueiredo, Marisa; Huang, Qin; Mashimo, Hiroshi; Cable, Alex E.; Fujimoto, James G.

    2014-03-01

    We developed an ultrahigh speed endoscopic swept source optical coherence tomography (OCT) system for clinical gastroenterology using a vertical-cavity surface-emitting laser (VCSEL) and micromotor based imaging catheter, which provided an imaging speed of 600 kHz axial scan rate and 8 μm axial resolution in tissue. The micromotor catheter was 3.2 mm in diameter and could be introduced through the 3.7 mm accessory port of an endoscope. Imaging was performed at 400 frames per second with an 8 μm spot size using a pullback to generate volumetric data over 16 mm with a pixel spacing of 5 μm in the longitudinal direction. Three-dimensional OCT (3D-OCT) imaging was performed in patients with a cross section of pathologies undergoing standard upper and lower endoscopy at the Veterans Affairs Boston Healthcare System (VABHS). Patients with Barrett's esophagus, dysplasia, and inflammatory bowel disease were imaged. The use of distally actuated imaging catheters allowed OCT imaging with more flexibility such as volumetric imaging in the terminal ileum and the assessment of the hiatal hernia using retroflex imaging. The high rotational stability of the micromotor enabled 3D volumetric imaging with micron scale volumetric accuracy for both en face and cross-sectional imaging. The ability to perform 3D OCT imaging in the GI tract with microscopic accuracy should enable a wide range of studies to investigate the ability of OCT to detect pathology as well as assess treatment response.

  11. Depth-encoded all-fiber swept source polarization sensitive OCT

    Science.gov (United States)

    Wang, Zhao; Lee, Hsiang-Chieh; Ahsen, Osman Oguz; Lee, ByungKun; Choi, WooJhon; Potsaid, Benjamin; Liu, Jonathan; Jayaraman, Vijaysekhar; Cable, Alex; Kraus, Martin F.; Liang, Kaicheng; Hornegger, Joachim; Fujimoto, James G.

    2014-01-01

    Polarization sensitive optical coherence tomography (PS-OCT) is a functional extension of conventional OCT and can assess depth-resolved tissue birefringence in addition to intensity. Most existing PS-OCT systems are relatively complex and their clinical translation remains difficult. We present a simple and robust all-fiber PS-OCT system based on swept source technology and polarization depth-encoding. Polarization multiplexing was achieved using a polarization maintaining fiber. Polarization sensitive signals were detected using fiber based polarization beam splitters and polarization controllers were used to remove the polarization ambiguity. A simplified post-processing algorithm was proposed for speckle noise reduction relaxing the demand for phase stability. We demonstrated systems design for both ophthalmic and catheter-based PS-OCT. For ophthalmic imaging, we used an optical clock frequency doubling method to extend the imaging range of a commercially available short cavity light source to improve polarization depth-encoding. For catheter based imaging, we demonstrated 200 kHz PS-OCT imaging using a MEMS-tunable vertical cavity surface emitting laser (VCSEL) and a high speed micromotor imaging catheter. The system was demonstrated in human retina, finger and lip imaging, as well as ex vivo swine esophagus and cardiovascular imaging. The all-fiber PS-OCT is easier to implement and maintain compared to previous PS-OCT systems and can be more easily translated to clinical applications due to its robust design. PMID:25401008

  12. Volumetric cutaneous microangiography of human skin in vivo by VCSEL swept-source optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Woo June Choi; Wang, R K [University of Washington, Department of Bioengineering, Seattle, Washington 98195 (United States)

    2014-08-31

    We demonstrate volumetric cutaneous microangiography of the human skin in vivo that utilises 1.3-μm high-speed sweptsource optical coherence tomography (SS-OCT). The swept source is based on a micro-electro-mechanical (MEMS)-tunable vertical cavity surface emission laser (VCSEL) that is advantageous in terms of long coherence length over 50 mm and 100 nm spectral bandwidth, which enables the visualisation of microstructures within a few mm from the skin surface. We show that the skin microvasculature can be delineated in 3D SS-OCT images using ultrahigh-sensitive optical microangiography (UHS-OMAG) with a correlation mapping mask, providing a contrast enhanced blood perfusion map with capillary flow sensitivity. 3D microangiograms of a healthy human finger are shown with distinct cutaneous vessel architectures from different dermal layers and even within hypodermis. These findings suggest that the OCT microangiography could be a beneficial biomedical assay to assess cutaneous vascular functions in clinic. (laser biophotonics)

  13. Volumetric cutaneous microangiography of human skin in vivo by VCSEL swept-source optical coherence tomography

    International Nuclear Information System (INIS)

    Woo June Choi; Wang, R K

    2014-01-01

    We demonstrate volumetric cutaneous microangiography of the human skin in vivo that utilises 1.3-μm high-speed sweptsource optical coherence tomography (SS-OCT). The swept source is based on a micro-electro-mechanical (MEMS)-tunable vertical cavity surface emission laser (VCSEL) that is advantageous in terms of long coherence length over 50 mm and 100 nm spectral bandwidth, which enables the visualisation of microstructures within a few mm from the skin surface. We show that the skin microvasculature can be delineated in 3D SS-OCT images using ultrahigh-sensitive optical microangiography (UHS-OMAG) with a correlation mapping mask, providing a contrast enhanced blood perfusion map with capillary flow sensitivity. 3D microangiograms of a healthy human finger are shown with distinct cutaneous vessel architectures from different dermal layers and even within hypodermis. These findings suggest that the OCT microangiography could be a beneficial biomedical assay to assess cutaneous vascular functions in clinic. (laser biophotonics)

  14. Characterization of FBG sensor interrogation based on a FDML wavelength swept laser

    Science.gov (United States)

    Jung, Eun Joo; Kim, Chang-Seok; Jeong, Myung Yung; Kim, Moon Ki; Jeon, Min Yong; Jung, Woonggyu; Chen, Zhongping

    2012-01-01

    In this study, we develop an ultra-fast fiber Bragg grating sensor system that is based on the Fourier domain mode-locked (FDML) swept laser. A FDML wavelength swept laser has many advantages compared to the conventional wavelength swept laser source, such as high-speed interrogation, narrow spectral sensitivity, and high phase stability. The newly developed FDML wavelength swept laser shows a superior performance of a high scan rate of 31.3 kHz and a broad scan range of over 70 nm simultaneously. The performance of the grating sensor interrogating system using a FDML wavelength swept laser is characterized in both static and dynamic strain responses. PMID:18852764

  15. Swept-sine noise-induced damage as a hearing loss model for preclinical assays

    Directory of Open Access Journals (Sweden)

    Lorena eSanz

    2015-02-01

    Full Text Available Mouse models are key tools for studying cochlear alterations in noise-induced hearing loss and for evaluating new therapies. Stimuli used to induce deafness in mice are usually white and octave band noises that include very low frequencies, considering the large mouse auditory range. We designed different sound stimuli, enriched in frequencies up to 20 kHz (violet noises to examine their impact on hearing thresholds and cochlear cytoarchitecture after short exposure. In addition, we developed a cytocochleogram to quantitatively assess the ensuing structural degeneration and its functional correlation. Finally, we used this mouse model and cochleogram procedure to evaluate the potential therapeutic effect of transforming growth factor β1 inhibitors P17 and P144 on noise-induced hearing loss. CBA mice were exposed to violet swept-sine noise with different frequency ranges (2-20 or 9-13 kHz and levels (105 or 120 dB SPL for 30 minutes. Mice were evaluated by auditory brainstem response and otoacoustic emission tests prior to and 2, 14 and 28 days after noise exposure. Cochlear pathology was assessed with gross histology; hair cell number was estimated by a stereological counting method. Our results indicate that functional and morphological changes induced by violet swept-sine noise depend on the sound level and frequency composition. Partial hearing recovery followed the exposure to 105 dB SPL, whereas permanent cochlear damage resulted from the exposure to 120 dB SPL. Exposure to 9-13 kHz noise caused an auditory threshold shift in those frequencies that correlated with hair cell loss in the corresponding areas of the cochlea that were spotted on the cytocochleogram. In summary, we present mouse models of noise-induced hearing loss, which depending on the sound properties of the noise, cause different degrees of cochlear damage, and could therefore be used to study molecules which are potential players in hearing loss protection and repair.

  16. Assessing embryo development using swept source optical coherence tomography

    Science.gov (United States)

    Caujolle, S.; Cernat, R.; Silvestri, G.; Marques, M. J.; Bradu, A.; Feuchter, T.; Robinson, G.; Griffin, D.; Podoleanu, A.

    2018-03-01

    A detailed assessment of embryo development would assist biologists with selecting the most suitable embryos for transfer leading to higher pregnancy rates. Currently, only low resolution microscopy is employed to perform this assessment. Although this method delivers some information on the embryo surface morphology, no specific details are shown related to its inner structure. Using a Master-Slave Swept-Source Optical Coherence Tomography (SS-OCT), images of bovine embryos from day 7 after fertilization were collected from different depths. The dynamic changes inside the embryos were examined, in detail and in real-time from several depths. To prove our ability to characterize the morphology, a single embryo was imaged over 26 hours. The embryo was deprived of its life support environment, leading to its death. Over this period, clear morphological changes were observed.

  17. Bed retained products in swept fixed bed (SFB) coal hydropyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Mastral, A.M.; Perez-Surio, M.J. [CSIC, Zaragosa (Spain). Inst. de Carboquimica

    1997-12-31

    The hydropyrolysis of a low rank coal in a swept fixed bed (SFB) reactor is carried out by fixing the hydrogen pressure (40 kg/cm{sup 2}), the hydrogen flow (2 l/min) and the residence time (10 min) at increasing temperatures (400 C, 500 C and 600 C) and coal bed heights (h, 1.5h, 2h, 2.5h and 3h). It is shown that the percentages of tars and char directly depend on the coal bed height and that there is not only a quantitative dependence, but also the height of the coal bed is very important and plays a relevant role on the nature of the conversion products. (orig.)

  18. Generalized Swept Mid-structure for Polygonal Models

    KAUST Repository

    Martin, Tobias; Chen, Guoning; Musuvathy, Suraj; Cohen, Elaine; Hansen, Charles

    2012-01-01

    We introduce a novel mid-structure called the generalized swept mid-structure (GSM) of a closed polygonal shape, and a framework to compute it. The GSM contains both curve and surface elements and has consistent sheet-by-sheet topology, versus triangle-by-triangle topology produced by other mid-structure methods. To obtain this structure, a harmonic function, defined on the volume that is enclosed by the surface, is used to decompose the volume into a set of slices. A technique for computing the 1D mid-structures of these slices is introduced. The mid-structures of adjacent slices are then iteratively matched through a boundary similarity computation and triangulated to form the GSM. This structure respects the topology of the input surface model is a hybrid mid-structure representation. The construction and topology of the GSM allows for local and global simplification, used in further applications such as parameterization, volumetric mesh generation and medical applications.

  19. Generalized Swept Mid-structure for Polygonal Models

    KAUST Repository

    Martin, Tobias

    2012-05-01

    We introduce a novel mid-structure called the generalized swept mid-structure (GSM) of a closed polygonal shape, and a framework to compute it. The GSM contains both curve and surface elements and has consistent sheet-by-sheet topology, versus triangle-by-triangle topology produced by other mid-structure methods. To obtain this structure, a harmonic function, defined on the volume that is enclosed by the surface, is used to decompose the volume into a set of slices. A technique for computing the 1D mid-structures of these slices is introduced. The mid-structures of adjacent slices are then iteratively matched through a boundary similarity computation and triangulated to form the GSM. This structure respects the topology of the input surface model is a hybrid mid-structure representation. The construction and topology of the GSM allows for local and global simplification, used in further applications such as parameterization, volumetric mesh generation and medical applications.

  20. Towards quantum signatures in a swept-bias Josephson junction

    Energy Technology Data Exchange (ETDEWEB)

    Losert, Harald; Vogel, Karl; Schleich, Wolfgang P. [Institut fuer Quantenphysik and Center for Integrated Quantum Science and Technology (IQST), Universitaet Ulm, D-89069 Ulm (Germany)

    2016-07-01

    Josephson junctions are one of the best examples for the observation of macroscopic quantum tunneling. The phase difference in a current-biased Josephson junction behaves like the position of a particle in a tilted washboard potential. The escape of this phase-particle corresponds to the voltage switching of the associated junction. Quantum mechanically, the escape from the washboard potential can be explained as tunneling from the ground state, or an excited state. However, it has been shown, that in the case of periodic driving the experimental data for quantum mechanical key features, e.g. Rabi oscillations or energy level quantization, can be reproduced by a completely classical description. Motivated by this discussion, we investigate a swept-bias Josephson junction in the case of a large critical current. In particular, we contrast the switching current distributions resulting from a quantum mechanical and classical description of the time evolution.

  1. Anterior chamber angle imaging with swept-source optical coherence tomography: measuring peripheral anterior synechia in glaucoma.

    Science.gov (United States)

    Lai, Isabel; Mak, Heather; Lai, Gilda; Yu, Marco; Lam, Dennis S C; Leung, Christopher K S

    2013-06-01

    To investigate the use of swept-source optical coherence tomography (OCT) for measuring the area and degree of peripheral anterior synechia (PAS) involvement in patients with angle-closure glaucoma. Cross-sectional study. Twenty-three eyes with PAS (detected by indentation gonioscopy) from 20 patients with angle-closure glaucoma (20 eyes had primary angle-closure glaucoma and 3 eyes had angle-closure glaucoma secondary to chronic anterior uveitis [n = 2] and Axenfeld-Rieger syndrome [n = 1]). The anterior chamber angles were evaluated with indentation gonioscopy and imaged by swept-source OCT (Casia OCT, Tomey, Nagoya, Japan) in room light and in the dark using the "angle analysis" protocol, which was composed of 128 radial B-scans each with 512 A-scans (16-mm scan length). The area and degree of PAS involvement were measured in each eye after manual detection of the scleral spur and the anterior irido-angle adhesion by 2 masked observers. The interobserver variability of the PAS measurements was calculated. The agreement of PAS assessment by gonioscopy and OCT, the area and the degree of PAS involvement, and the intraclass correlation coefficient (ICC) of interobserver PAS measurements. The area of PAS (mean ± standard deviation) was 20.8 ± 16.9 mm(2) (range, 3.9-74.9 mm(2)), and the degree of PAS involvement was 186.5 ± 79.9 degrees (range, 42-314 degrees). There was no difference in the area of PAS (P = 0.90) and the degree of PAS involvement (P = 0.95) between images obtained in room light and in the dark. The interobserver ICCs were 0.99 (95% confidence interval [CI], 0.98-1.00) for the area of PAS and 0.99 (95% CI, 0.97-1.00) for the degree of PAS involvement. There was good agreement of PAS assessment between gonioscopy and OCT images (kappa = 0.79; 95% CI, 0.67-0.91). Swept-source OCT allows visualization and reproducible measurements of the area and degree of PAS involvement, providing a new paradigm for evaluation of PAS progression and risk assessment

  2. Experimental study of a swept reflectometer with a single antenna for plasma density profile measurement

    International Nuclear Information System (INIS)

    Calderon, M.A.G.; Simonet, F.

    1984-12-01

    The feasibility of a swept microwave reflectometer, with one antenna only, for plasma electron density measurement is studied. Experimental results obtained in the laboratory by simulating the plasma with a metallic mirror are presented

  3. Use of Correlation Relationships to Enhance Understanding of Pedogenic Processes and Use Potential of Vertisols and Vertic Inceptisols of the Bale Mountain Area of Ethiopia

    Directory of Open Access Journals (Sweden)

    Verdoodt, A.

    2009-01-01

    Full Text Available Five Vertisols and two Vertic Inceptisols developed from basalt and alluvial materials were characterized for physical and chemical properties. Correlative statistical relationships were established among physical and chemical properties including cation exchange capacity (CEC, percent total clay, electrical conductivity (EC, base saturation % (BS, pH-H2O, pH-KCl, CaCO3 equivalent, organic carbon (OC, total nitrogen (TN, P-Bray and P-Olsen. Correlative relationships were established among parameters for all horizons of the soils studied as well as among parameters within individual horizons. P-Olsen was highly correlated with OC and TN; simple coefficients of determination (r2 were 0.81 and 0.69, respectively. CaCO3 was highly correlated with pH-H2O and pH-KCl; r2 values were 0.68 and 0.60, respectively. Similar correlations were obtained for pHKCl vs pH-H2O and pH-KCl vs EC, with r2 values of 0.92 and 0.70, respectively. Total nitrogen was also very highly correlated with OC (r2= 0.88. Base saturation was highly correlated with pH-KCl and pH-H2O giving r2 values of 0.62 and 0.64, respectively. When correlative relationships were carried out among parameters within individual horizons very high correlation coefficients were obtained for OC vs TN (r= 0.98 - 1.00, OC vs P-Olsen (r= 0.96 - 0.99, BS vs pH-KCl (r= 0.82 - 1.00, BS vs pH-H2O (r= 0.86 - 1.00. Most of the simple correlation coefficients obtained for EC with pH-KCl and pH-H2O were > 0.81. High correlation coefficients (0.80 - 1.00 were obtained for % clay vs total CEC for most soils studied. Regression relationships developed constitute useful predictive indices for estimating agronomic properties from existing physical and chemical data and soil survey reports of the Bale Mountain area of Ethiopia. This study has demonstrated that statistical correlation can be used to cross-check the quality of analytical data both among horizons of different soil profiles and within individual soil

  4. Performance analysis of a full-field and full-range swept-source OCT system

    Science.gov (United States)

    Krauter, J.; Boettcher, T.; Körner, K.; Gronle, M.; Osten, W.; Passilly, N.; Froehly, L.; Perrin, S.; Gorecki, C.

    2015-09-01

    In recent years, optical coherence tomography (OCT) became gained importance in medical disciplines like ophthalmology, due to its noninvasive optical imaging technique with micrometer resolution and short measurement time. It enables e. g. the measurement and visualization of the depth structure of the retina. In other medical disciplines like dermatology, histopathological analysis is still the gold standard for skin cancer diagnosis. The EU-funded project VIAMOS (Vertically Integrated Array-type Mirau-based OCT System) proposes a new type of OCT system combined with micro-technologies to provide a hand-held, low-cost and miniaturized OCT system. The concept is a combination of full-field and full-range swept-source OCT (SS-OCT) detection in a multi-channel sensor based on a micro-optical Mirau-interferometer array, which is fabricated by means of wafer fabrication. This paper presents the study of an experimental proof-of-concept OCT system as a one-channel sensor with bulk optics. This sensor is a Linnik-interferometer type with similar optical parameters as the Mirau-interferometer array. A commercial wavelength tunable light source with a center wavelength at 845nm and 50nm spectral bandwidth is used with a camera for parallel OCT A-Scan detection. In addition, the reference microscope objective lens of the Linnik-interferometer is mounted on a piezo-actuated phase-shifter. Phase-shifting interferometry (PSI) techniques are applied for resolving the conjugate complex artifact and consequently contribute to an increase of image quality and depth range. A suppression ratio of the complex conjugate term of 36 dB is shown and a system sensitivity greater than 96 dB could be measured.

  5. Handheld ultrahigh speed swept source optical coherence tomography instrument using a MEMS scanning mirror.

    Science.gov (United States)

    Lu, Chen D; Kraus, Martin F; Potsaid, Benjamin; Liu, Jonathan J; Choi, Woojhon; Jayaraman, Vijaysekhar; Cable, Alex E; Hornegger, Joachim; Duker, Jay S; Fujimoto, James G

    2013-12-20

    We developed an ultrahigh speed, handheld swept source optical coherence tomography (SS-OCT) ophthalmic instrument using a 2D MEMS mirror. A vertical cavity surface-emitting laser (VCSEL) operating at 1060 nm center wavelength yielded a 350 kHz axial scan rate and 10 µm axial resolution in tissue. The long coherence length of the VCSEL enabled a 3.08 mm imaging range with minimal sensitivity roll-off in tissue. Two different designs with identical optical components were tested to evaluate handheld OCT ergonomics. An iris camera aided in alignment of the OCT beam through the pupil and a manual fixation light selected the imaging region on the retina. Volumetric and high definition scans were obtained from 5 undilated normal subjects. Volumetric OCT data was acquired by scanning the 2.4 mm diameter 2D MEMS mirror sinusoidally in the fast direction and linearly in the orthogonal slow direction. A second volumetric sinusoidal scan was obtained in the orthogonal direction and the two volumes were processed with a software algorithm to generate a merged motion-corrected volume. Motion-corrected standard 6 x 6 mm(2) and wide field 10 x 10 mm(2) volumetric OCT data were generated using two volumetric scans, each obtained in 1.4 seconds. High definition 10 mm and 6 mm B-scans were obtained by averaging and registering 25 B-scans obtained over the same position in 0.57 seconds. One of the advantages of volumetric OCT data is the generation of en face OCT images with arbitrary cross sectional B-scans registered to fundus features. This technology should enable screening applications to identify early retinal disease, before irreversible vision impairment or loss occurs. Handheld OCT technology also promises to enable applications in a wide range of settings outside of the traditional ophthalmology or optometry clinics including pediatrics, intraoperative, primary care, developing countries, and military medicine.

  6. The effect of protons on the performance of swept-charge devices

    International Nuclear Information System (INIS)

    Smith, David R.; Gow, Jason

    2009-01-01

    The e2v technologies CCD54, or swept-charge device (SCD) has been extensively radiation tested for use in the Chandrayaan-1 X-ray Spectrometer (C1XS) instrument, to be launched as a part of the Indian Space Research Organisation (ISRO) Chandrayaan-1 payload in 2008. The principle use of the SCD is in X-ray fluorescence (XRF) applications, the device providing a relatively large collecting area of 1.1 cm 2 , and achieving near Fano-limited spectroscopy at -15 deg. C, a temperature that is easily obtained using a thermoelectric cooler (TEC). This paper describes the structure and operation of the SCD and details the methodology and results obtained from two proton irradiation studies carried out in 2006 and 2008, respectively to quantify the effects of proton irradiation on the operational characteristics of the device. The analysis concentrates on the degradation of the measured FWHM of various elemental lines and quantifies the effects of proton fluence on the observed X-ray fluorescence spectra from mineralogical target samples.

  7. Swept source optical coherence tomography for quantitative and qualitative assessment of dental composite restorations

    Science.gov (United States)

    Sadr, Alireza; Shimada, Yasushi; Mayoral, Juan Ricardo; Hariri, Ilnaz; Bakhsh, Turki A.; Sumi, Yasunori; Tagami, Junji

    2011-03-01

    The aim of this work was to explore the utility of swept-source optical coherence tomography (SS-OCT) for quantitative evaluation of dental composite restorations. The system (Santec, Japan) with a center wavelength of around 1300 nm and axial resolution of 12 μm was used to record data during and after placement of light-cured composites. The Fresnel phenomenon at the interfacial defects resulted in brighter areas indicating gaps as small as a few micrometers. The gap extension at the interface was quantified and compared to the observation by confocal laser scanning microscope after trimming the specimen to the same cross-section. Also, video imaging of the composite during polymerization could provide information about real-time kinetics of contraction stress and resulting gaps, distinguishing them from those gaps resulting from poor adaptation of composite to the cavity prior to polymerization. Some samples were also subjected to a high resolution microfocus X-ray computed tomography (μCT) assessment; it was found that differentiation of smaller gaps from the radiolucent bonding layer was difficult with 3D μCT. Finally, a clinical imaging example using a newly developed dental SS-OCT system with an intra-oral scanning probe (Panasonic Healthcare, Japan) is presented. SS-OCT is a unique tool for clinical assessment and laboratory research on resin-based dental restorations. Supported by GCOE at TMDU and NCGG.

  8. Parametric Study of Swept Impinging Oblique Shock/Boundary Layer Interactions

    Science.gov (United States)

    Doehrmann, Adam; Threadgill, James; Little, Jesse

    2017-11-01

    Modern high-speed vehicles have increasingly complex 3D geometries featuring: surface curvature, variable aspect ratio inlet ducts and swept bodies. Such distortion to the flow field necessitates a further understanding of swept 3D Shock/Boundary Layer Interactions (SBLIs), where various regimes of spanwise interaction development have been observed. A parametric experimental study of swept oblique impinging SBLIs has been conducted comparing cylindrical and conical interaction structures to that of swept compression ramps in previous work. This investigation examines five shock generators with 2D deflection of θ = 12 .5° and varying degrees of sweep (ψ = 10 .0° , 15 .0° , 22 .5° , 30 .0° , 40 .0°), with an incoming turbulent flow at Mach 2.3 and 3.0. Parametric characterization of surface oil-flow visualizations has shown that the inception length of the interaction follows a similar trend to that seen in swept compression ramps as sweep is varied, namely that it increases as sweep approaches a critical angle. However, this criteria disagrees with direct observations of separation and reattachment angles. Similarities in mean pressures profiles have also been assessed and analyzed with respect to the onset of a cylindrical/conical interaction. Supported by the Air Force Office of Scientific Research (FA9550-15-1-0430).

  9. Experimental Investigation of a Forward Swept Rotor in a Multistage Fan with Inlet Distortion

    Directory of Open Access Journals (Sweden)

    Aspi R. Wadia

    2011-01-01

    Full Text Available Previous studies of transonic swept rotors in single stage fans have demonstrated the potential of significant improvements in both efficiency and stall margin with forward swept blading. This paper extends the assessment of the payoff derived from forward sweep to multistage configurations. The experimental investigation compare two builds of an advanced two-stage fan configuration tested alternately with a radial and a forward swept stage 1 blade. In the two-stage evaluations, the testing was extended to include the effect on inlet flow distortion. While the common second stage among the two builds prevented the overall fan from showing clean inlet performance and stability benefits with the forward swept rotor 1, this configuration did demonstrate superior front stage efficiency and tolerance to inlet distortion. Having obtained already low distortion sensitivity with the radial rotor 1 configuration relative to current production military fan standards, the sensitivity to inlet distortion was halved with the forward swept rotor 1 configuration. In the case of the 180-degree one-per-rev distortion pattern, the two-stage configuration was evaluated both with and without inlet guide vanes (IGVs. The presence of the inlet guide vanes had a profound impact in lowering the two-stage fan's sensitivity with inlet distortion.

  10. Uniform Self-rectifying Resistive Switching Behavior via Preformed Conducting Paths in a Vertical-type Ta2O5/HfO2-x Structure with a Sub-μm(2) Cell Area.

    Science.gov (United States)

    Yoon, Jung Ho; Yoo, Sijung; Song, Seul Ji; Yoon, Kyung Jean; Kwon, Dae Eun; Kwon, Young Jae; Park, Tae Hyung; Kim, Hye Jin; Shao, Xing Long; Kim, Yumin; Hwang, Cheol Seong

    2016-07-20

    To replace or succeed the present NAND flash memory, resistive switching random access memory (ReRAM) should be implemented in the vertical-type crossbar array configuration. The ReRAM cell must have a highly reproducible resistive switching (RS) performance and an electroforming-free, self-rectifying, low-power-consumption, multilevel-switching, and easy fabrication process with a deep sub-μm(2) cell area. In this work, a Pt/Ta2O5/HfO2-x/TiN RS memory cell fabricated in the form of a vertical-type structure was presented as a feasible contender to meet the above requirements. While the fundamental RS characteristics of this material based on the electron trapping/detrapping mechanisms have been reported elsewhere, the influence of the cell scaling size to 0.34 μm(2) on the RS performance by adopting the vertical integration scheme was carefully examined in this work. The smaller cell area provided much better switching uniformity while all the other benefits of this specific material system were preserved. Using the overstressing technique, the nature of RS through the localized conducting path was further examined, which elucidated the fundamental difference between the present material system and the general ionic-motion-related bipolar RS mechanism.

  11. Evaluation of focal choroidal excavation in the macula using swept-source optical coherence tomography.

    Science.gov (United States)

    Lim, F P M; Loh, B K; Cheung, C M G; Lim, L S; Chan, C M; Wong, D W K

    2014-09-01

    To evaluate imaging findings of patients with focal choroidal excavation (FCE) in the macula using swept-source optical coherence tomography (SS-OCT) and correlate it clinically. Prospective observational case series. Eleven consecutive patients (12 eyes) with FCE were described. Data on demographics and clinical presentation were collected and imaging findings (including color photography, fundus autofluorescence imaging, fluorescein angiography, indocyanine green angiography, spectral-domain optical coherence tomography, and SS-OCT) were analyzed. The primary diagnosis was epiretinal membrane (two eyes), choroidal neovascularization (one eye), polypoidal choroidal vasculopathy (three eyes), central serous chorioretinopathy (one eye), and dry age-related macular degeneration (two eyes). Eleven out of 12 of the lesions were conforming. One presented with a non-conforming lesion that progressed to a conforming lesion. One eye had multiFCE and two had two overlapping choroidal excavations. Using the SS-OCT, we found the choroid to be thinned out at the area of FCE but sclera remained normal. The choroidal tissue beneath the FCE was abnormal, with high internal reflectivity and poor visualization of choroidal vessels. There was loss of contour of the outer choroidal boundary that appeared to be pulled inward by this abnormal choroidal tissue. A suprachoroidal space was noted beneath this choroidal tissue and the choroidal-scleral interface was smooth. Repeat SS-OCT 6 months after presentation showed the area of excavation to be stable in size. FCE can be associated with epiretinal membrane, central serous chorioretinopathy, and age-related macular degeneration. The choroid was thinned out in the area of FCE.

  12. Evaluation of focal choroidal excavation in the macula using swept-source optical coherence tomography

    Science.gov (United States)

    Lim, F P M; Loh, B K; Cheung, C M G; Lim, L S; Chan, C M; Wong, D W K

    2014-01-01

    Purpose To evaluate imaging findings of patients with focal choroidal excavation (FCE) in the macula using swept-source optical coherence tomography (SS-OCT) and correlate it clinically. Methods Prospective observational case series. Eleven consecutive patients (12 eyes) with FCE were described. Data on demographics and clinical presentation were collected and imaging findings (including color photography, fundus autofluorescence imaging, fluorescein angiography, indocyanine green angiography, spectral-domain optical coherence tomography, and SS-OCT) were analyzed. Results The primary diagnosis was epiretinal membrane (two eyes), choroidal neovascularization (one eye), polypoidal choroidal vasculopathy (three eyes), central serous chorioretinopathy (one eye), and dry age-related macular degeneration (two eyes). Eleven out of 12 of the lesions were conforming. One presented with a non-conforming lesion that progressed to a conforming lesion. One eye had multiFCE and two had two overlapping choroidal excavations. Using the SS-OCT, we found the choroid to be thinned out at the area of FCE but sclera remained normal. The choroidal tissue beneath the FCE was abnormal, with high internal reflectivity and poor visualization of choroidal vessels. There was loss of contour of the outer choroidal boundary that appeared to be pulled inward by this abnormal choroidal tissue. A suprachoroidal space was noted beneath this choroidal tissue and the choroidal–scleral interface was smooth. Repeat SS-OCT 6 months after presentation showed the area of excavation to be stable in size. Conclusion FCE can be associated with epiretinal membrane, central serous chorioretinopathy, and age-related macular degeneration. The choroid was thinned out in the area of FCE. PMID:24946847

  13. Long ranging swept-source optical coherence tomography-based angiography outperforms its spectral-domain counterpart in imaging human skin microcirculations

    Science.gov (United States)

    Xu, Jingjiang; Song, Shaozhen; Men, Shaojie; Wang, Ruikang K.

    2017-11-01

    There is an increasing demand for imaging tools in clinical dermatology that can perform in vivo wide-field morphological and functional examination from surface to deep tissue regions at various skin sites of the human body. The conventional spectral-domain optical coherence tomography-based angiography (SD-OCTA) system is difficult to meet these requirements due to its fundamental limitations of the sensitivity roll-off, imaging range as well as imaging speed. To mitigate these issues, we demonstrate a swept-source OCTA (SS-OCTA) system by employing a swept source based on a vertical cavity surface-emitting laser. A series of comparisons between SS-OCTA and SD-OCTA are conducted. Benefiting from the high system sensitivity, long imaging range, and superior roll-off performance, the SS-OCTA system is demonstrated with better performance in imaging human skin than the SD-OCTA system. We show that the SS-OCTA permits remarkable deep visualization of both structure and vasculature (up to ˜2 mm penetration) with wide field of view capability (up to 18×18 mm2), enabling a more comprehensive assessment of the morphological features as well as functional blood vessel networks from the superficial epidermal to deep dermal layers. It is expected that the advantages of the SS-OCTA system will provide a ground for clinical translation, benefiting the existing dermatological practice.

  14. Spectro-refractometry of individual microscopic objects using swept-source quantitative phase imaging.

    Science.gov (United States)

    Jung, Jae-Hwang; Jang, Jaeduck; Park, Yongkeun

    2013-11-05

    We present a novel spectroscopic quantitative phase imaging technique with a wavelength swept-source, referred to as swept-source diffraction phase microscopy (ssDPM), for quantifying the optical dispersion of microscopic individual samples. Employing the swept-source and the principle of common-path interferometry, ssDPM measures the multispectral full-field quantitative phase imaging and spectroscopic microrefractometry of transparent microscopic samples in the visible spectrum with a wavelength range of 450-750 nm and a spectral resolution of less than 8 nm. With unprecedented precision and sensitivity, we demonstrate the quantitative spectroscopic microrefractometry of individual polystyrene beads, 30% bovine serum albumin solution, and healthy human red blood cells.

  15. Commercial Digital Camera to Estimate Postharvest Leaf Area Index in Vitis vinifera L. cv. Cabernet Sauvignon on a Vertical Trellis Uso de una Cámara Digital Comercial para Estimar el Índice de Área Foliar en Vitis vinifera L. cv. Cabernet Sauvignon en Poscosecha Conducida en Espaldera Vertical

    Directory of Open Access Journals (Sweden)

    Miguel Espinosa L.

    2010-06-01

    Full Text Available The leaf area index (LAI of a vineyard (Vitis vinifera L. cv. Cabernet Sauvignon located in the commune of Cauquenes, Maule Region in Chile, was estimated from digital images obtained with a commercial camera using two indirect methods: Leaf Area Gap and Brightness (LAGB and -Photogrammetric Leaf Area Quantification System (PLAQS. The latter requires deleafing of the grapevine. In a normalized difference vegetation index (NDVI map, three points of vine vigor were selected: high, medium, and low for which horizontal and vertical images were obtained. Images were filtered with the Arc View GIS 3.1 program to provide only leaf images and corresponding pixel numbers. Image area and square meters per linear meter were calculated. The best models were selected from  three linear regression adjustments: i LAI of LAGB vertical images of with LAI of PLAQS, ii LAI of PLAQS horizontal images with and, iii LAI of both types of images with PLAQS. The parameters in all models were significant. Adjustment between the LAGB and PLAQS vertical images provides greater simplicity and easy calculation since it requires only a vertical image to estimate LAI. Images thus obtained can accurately estimate LAI in this type of cultivar.En un viñedo (Vitis vinifera L. cv. Cabernet Sauvignon ubicado en la comuna de Cauquenes, Región del Maule, se estimó el índice de área foliar (LAI mediante imagen digital obtenida de una cámara fotográfica comercial, a partir de dos métodos indirectos: Espacio y Brillo Área Foliar (LAGB y Sistema Cuantificador de Área Foliar por Fotogrametría (PLAQS. Este último, requiere el deshoje de la parra. En un mapa de índice vegetativo diferencial normalizado (NDVI, se seleccionaron tres puntos de vigor de las vides: alto, medio y bajo, en cada uno de los cuales se obtuvo una imagen horizontal y vertical. Las imágenes se filtraron con el programa Arc View GIS 3.1, dejando sólo las hojas y el número de píxeles correspondientes. Se

  16. Proton irradiation of a swept charge device at cryogenic temperature and the subsequent annealing

    International Nuclear Information System (INIS)

    Gow, J P D; Smith, P H; Hall, D J; Holland, A D; Murray, N J; Pool, P

    2015-01-01

    A number of studies have demonstrated that a room temperature proton irradiation may not be sufficient to provide an accurate estimation of the impact of the space radiation environment on detector performance. This is a result of the relationship between defect mobility and temperature, causing the performance to vary subject to the temperature history of the device from the point at which it was irradiated. Results measured using Charge Coupled Devices (CCD) irradiated at room temperature therefore tend to differ from those taken when the device was irradiated at a cryogenic temperature, more appropriate considering the operating conditions in space, impacting the prediction of in-flight performance. This paper describes the cryogenic irradiation, and subsequent annealing of an e2v technologies Swept Charge Device (SCD) CCD236 irradiated at −35.4°C with a 10 MeV equivalent proton fluence of 5.0 × 10 8 protons · cm −2 . The CCD236 is a large area (4.4 cm 2 ) X-ray detector that will be flown on-board the Chandrayaan-2 and Hard X-ray Modulation Telescope spacecraft, in the Chandrayaan-2 Large Area Soft X-ray Spectrometer and the Soft X-ray Detector respectively. The SCD is readout continually in order to benefit from intrinsic dither mode clocking, leading to suppression of the surface component of the dark current and allowing the detector to be operated at warmer temperatures than a conventional CCD. The SCD is therefore an excellent choice to test and demonstrate the variation in the impact of irradiation at cryogenic temperatures in comparison to a more typical room temperature irradiation

  17. Step edge influence on barrier height and contact area in vertical heterojunctions between epitaxial graphene and n-type 4H-SiC

    International Nuclear Information System (INIS)

    Tadjer, M. J.; Nyakiti, L. O.; Robinson, Z.; Anderson, T. J.; Myers-Ward, R. L.; Wheeler, V. D.; Eddy, C. R.; Gaskill, D. K.; Koehler, A. D.; Hobart, K. D.; Kub, F. J.

    2014-01-01

    Vertical rectifying contacts of epitaxial graphene grown by Si sublimation on the Si-face of 4H-SiC epilayers were investigated. Forward bias preferential conduction through the step edges was correlated by linear current density normalization. This phenomenon was observed on samples with 2.7–5.8 monolayers of epitaxial graphene as determined by X-ray photoelectron spectroscopy. A modified Richardson plot was implemented to extract the barrier height (0.81 eV at 290 K, 0.99 eV at 30 K) and the electrically dominant SiC step length of a Ti/Al contact overlapping a known region of approximately 0.52 μm wide SiC terraces

  18. Tunable, multiwavelength-swept fiber laser based on nematic liquid crystal device for fiber-optic electric-field sensor

    Science.gov (United States)

    Lee, Hyun Ji; Kim, Sung-Jo; Ko, Myeong Ock; Kim, Jong-Hyun; Jeon, Min Yong

    2018-03-01

    We propose a tunable multiwavelength-swept laser based on a nematic liquid crystal (NLC) Fabry-Perot (FP) etalon, which is embedded in the resonator of a wavelength-swept laser. We achieve the continuous wavelength tuning of the multiwavelength-swept laser by applying the electric field to the NLC FP etalon. The free spectral range of the fabricated NLC FP etalon is approximately 7.9 nm. When the electric field applied to the NLC FP etalon exceeds the threshold value (Fréedericksz threshold voltage), the output of the multiwavelength-swept laser can be tuned continuously. The tuning range of the multiwavelength-swept laser can be achieved at a value greater than 75 nm, which has a considerably wider tunable range than a conventional multiwavelength laser based on an NLC FP etalon. The slope efficiencies in the spectral and temporal domains for the tunable multiwavelength-swept laser are 22.2 nm/(mVrms / μm) and 0.17 ms/(mVrms / μm), respectively in the linear region. Therefore, the developed multiwavelength-swept laser based on the NLC FP etalon can be applied to an electric-field sensor. Because the wavelength measurement and time measurement have a linear relationship, the electric-field sensor can detect a rapid change in the electric-field intensity by measuring the peak change of the pulse in the temporal domain using the NLC FP etalon-based multiwavelength-swept laser.

  19. Two configurations of miniature Mirau interferometry for swept-source OCT imaging: applications in dermatology and gastroendoscopy

    Science.gov (United States)

    Gorecki, Christophe

    2015-08-01

    The early diagnosis of cancer is essential since it can be treated more effectively when detected earlier. Visual inspection followed by histological examination is, still today, the gold standard for clinicians. However, a large number of unnecessary surgical procedures are still performed. New diagnostics aids are emerging including the recent techniques of optical coherence tomography (OCT) which permits non-invasive 3D optical biopsies of biological tissues, improving patient's quality of life. Nevertheless, the existing bulk or fiber optics systems are expensive, only affordable at the hospital and thus, not sufficiently used by physicians or cancer's specialists as an early diagnosis tool. We developed two different microsystems based on Mirau interferometry and applied for swept source OCT imaging: one for dermatology and second for gastroenterology. In both cases the architecture is based tem based on spectrally tuned Mirau interferometry. The first configuration, developed in the frame of the European project VIAMOS, includes an active array of 4x4 Mirau interferometers. The matrix of Mirau reference mirrors is integrated on top of an electrostatic vertical comb-drive actuator. In second configuration, developed in the frame of Labex ACTION, we adapted VIAMOS technology to develop an OCT endomicroscope with a single-channel passive Mirau interferometer.

  20. Microscope-Integrated Intraoperative Ultrahigh-Speed Swept-Source Optical Coherence Tomography for Widefield Retinal and Anterior Segment Imaging.

    Science.gov (United States)

    Lu, Chen D; Waheed, Nadia K; Witkin, Andre; Baumal, Caroline R; Liu, Jonathan J; Potsaid, Benjamin; Joseph, Anthony; Jayaraman, Vijaysekhar; Cable, Alex; Chan, Kinpui; Duker, Jay S; Fujimoto, James G

    2018-02-01

    To demonstrate the feasibility of retinal and anterior segment intraoperative widefield imaging using an ultrahigh-speed, swept-source optical coherence tomography (SS-OCT) surgical microscope attachment. A prototype post-objective SS-OCT using a 1,050-nm wavelength, 400 kHz A-scan rate, vertical cavity surface-emitting laser (VCSEL) light source was integrated to a commercial ophthalmic surgical microscope after the objective. Each widefield OCT data set was acquired in 3 seconds (1,000 × 1,000 A-scans, 12 × 12 mm 2 for retina and 10 × 10 mm 2 for anterior segment). Intraoperative SS-OCT was performed in 20 eyes of 20 patients. In six of seven membrane peels and five of seven rhegmatogenous retinal detachment repair surgeries, widefield retinal imaging enabled evaluation pre- and postoperatively. In all seven cataract cases, anterior imaging evaluated the integrity of the posterior lens capsule. Ultrahigh-speed SS-OCT enables widefield intraoperative viewing in the posterior and anterior eye. Widefield imaging visualizes ocular structures and pathology without requiring OCT realignment. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:94-102.]. Copyright 2018, SLACK Incorporated.

  1. Study of the feasibility aspects of flight testing an aeroelastically tailored forward swept research wing on a BQM-34F drone vehicle

    Science.gov (United States)

    Mourey, D. J.

    1979-01-01

    The aspects of flight testing an aeroelastically tailored forward swept research wing on a BQM-34F drone vehicle are examined. The geometry of a forward swept wing, which is incorporated into the BQM-34F to maintain satisfactory flight performance, stability, and control is defined. A preliminary design of the aeroelastically tailored forward swept wing is presented.

  2. Fourier domain mode-locked swept source at 1050 nm based on a tapered amplifier

    DEFF Research Database (Denmark)

    Marschall, Sebastian; Klein, Thomas; Wieser, Wolfgang

    2010-01-01

    While swept source optical coherence tomography (OCT) in the 1050 nm range is promising for retinal imaging, there are certain challenges. Conventional semiconductor gain media have limited output power, and the performance of high-speed Fourier domain mode-locked (FDML) lasers suffers from...

  3. Wide and Fast Wavelength-Swept Fiber Laser Based on Dispersion Tuning for Dynamic Sensing

    Directory of Open Access Journals (Sweden)

    Shinji Yamashita

    2009-01-01

    Full Text Available We have developed a unique wide and fast wavelength-swept fiber laser for dynamic and accurate fiber sensing. The wavelength tuning is based on the dispersion tuning technique, which simply modulates the loss/gain in the dispersive laser cavity. By using wideband semiconductor optical amplifiers (SOAs, the sweep range could be as wide as ∼180 nm. Since the cavity contains no mechanical components, such as tunable filters, we could achieve very high sweep rate, as high as ∼200 kHz. We have realized the swept lasers at three wavelength bands, 1550 nm, 1300 nm, and 800 nm, using SOAs along with erbium-doped fiber amplifiers (EDFAs, and in two laser configurations, ring and linear ones. We also succeeded in applying the swept laser for a dynamic fiber-Bragg grating (FBG sensor system. In this paper, we review our researches on the wide and fast wavelength-swept fiber lasers.

  4. Appraisal of numerical methods in predicting the aerodynamics of forward-swept wings

    CSIR Research Space (South Africa)

    Lombardi, G

    1998-07-01

    Full Text Available The capabilities of different numerical methods in evaluating the aerodynamic characteristics of a forward-swept wing in subsonic and transonic now are analyzed. The numerical results, obtained by means of potential, Euler, and Navier-Stokes solvers...

  5. High-speed high-sensitivity infrared spectroscopy using mid-infrared swept lasers (Conference Presentation)

    Science.gov (United States)

    Childs, David T. D.; Groom, Kristian M.; Hogg, Richard A.; Revin, Dmitry G.; Cockburn, John W.; Rehman, Ihtesham U.; Matcher, Stephen J.

    2016-03-01

    Infrared spectroscopy is a highly attractive read-out technology for compositional analysis of biomedical specimens because of its unique combination of high molecular sensitivity without the need for exogenous labels. Traditional techniques such as FTIR and Raman have suffered from comparatively low speed and sensitivity however recent innovations are challenging this situation. Direct mid-IR spectroscopy is being speeded up by innovations such as MEMS-based FTIR instruments with very high mirror speeds and supercontinuum sources producing very high sample irradiation levels. Here we explore another possible method - external cavity quantum cascade lasers (EC-QCL's) with high cavity tuning speeds (mid-IR swept lasers). Swept lasers have been heavily developed in the near-infrared where they are used for non-destructive low-coherence imaging (OCT). We adapt these concepts in two ways. Firstly by combining mid-IR quantum cascade gain chips with external cavity designs adapted from OCT we achieve spectral acquisition rates approaching 1 kHz and demonstrate potential to reach 100 kHz. Secondly we show that mid-IR swept lasers share a fundamental sensitivity advantage with near-IR OCT swept lasers. This makes them potentially able to achieve the same spectral SNR as an FTIR instrument in a time x N shorter (N being the number of spectral points) under otherwise matched conditions. This effect is demonstrated using measurements of a PDMS sample. The combination of potentially very high spectral acquisition rates, fundamental SNR advantage and the use of low-cost detector systems could make mid-IR swept lasers a powerful technology for high-throughput biomedical spectroscopy.

  6. PENDEKATAN GEOSTATISTIKA DALAM PENDUGAAN KELIMPAHAN IKAN DEMERSAL DENGAN METODE SWEPT AREA DI PERAIRAN UTARA JAWA TENGAH

    Directory of Open Access Journals (Sweden)

    Moh. Natsir

    2016-03-01

    This research is intended to apply geostatistical analysis in fish abundance estimation in the north Java waters. Geostatistical is a series of methods to examine one or more spatially distributed variables through structure analysis of the data. Trawl data obtained using the bottom trawl operated by Bawal Putih vessel. Data processing includes the standardization of catch, geographic position transformation to UTM format, variogram model fitting and abundance prediction using the model. Analysis of trawl data structure was done by using geostatistical analysis, estimation results of the experimental semi-variogram were then used to infer the characteristics of demersal fish abundance in the north of central Java waters. Results of structural analysis and models fitting using geostatistical analysis showed that the most suitable model with all data used were spherical model with different parameters from each model. The models are then used to estimate the value of fish abundance on the points that there is no abundance information through kriging interpolation process. Results of cross-validation of the estimated abundance using kriging with actual values shows that R2 values varied for each data set. Geostatistical prediction results showed smaller coefficients of variation compare to arithmetic calculations.

  7. Large Eddy Simulation of Vertical Axis Wind Turbine Wakes

    Directory of Open Access Journals (Sweden)

    Sina Shamsoddin

    2014-02-01

    Full Text Available In this study, large eddy simulation (LES is combined with a turbine model to investigate the wake behind a vertical-axis wind turbine (VAWT in a three-dimensional turbulent flow. Two methods are used to model the subgrid-scale (SGS stresses: (a the Smagorinsky model; and (b the modulated gradient model. To parameterize the effects of the VAWT on the flow, two VAWT models are developed: (a the actuator swept-surface model (ASSM, in which the time-averaged turbine-induced forces are distributed on a surface swept by the turbine blades, i.e., the actuator swept surface; and (b the actuator line model (ALM, in which the instantaneous blade forces are only spatially distributed on lines representing the blades, i.e., the actuator lines. This is the first time that LES has been applied and validated for the simulation of VAWT wakes by using either the ASSM or the ALM techniques. In both models, blade-element theory is used to calculate the lift and drag forces on the blades. The results are compared with flow measurements in the wake of a model straight-bladed VAWT, carried out in the Institute de Méchanique et Statistique de la Turbulence (IMST water channel. Different combinations of SGS models with VAWT models are studied, and a fairly good overall agreement between simulation results and measurement data is observed. In general, the ALM is found to better capture the unsteady-periodic nature of the wake and shows a better agreement with the experimental data compared with the ASSM. The modulated gradient model is also found to be a more reliable SGS stress modeling technique, compared with the Smagorinsky model, and it yields reasonable predictions of the mean flow and turbulence characteristics of a VAWT wake using its theoretically-determined model coefficient.

  8. Global Vertical Reference Frame

    Czech Academy of Sciences Publication Activity Database

    Burša, Milan; Kenyon, S.; Kouba, J.; Šíma, Zdislav; Vatrt, V.; Vojtíšková, M.

    2004-01-01

    Roč. 33, - (2004), s. 404-407 ISSN 1436-3445 Institutional research plan: CEZ:AV0Z1003909 Keywords : geopotential WO * vertical systems * global vertical frame Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  9. Development of Experimental Icing Simulation Capability for Full-Scale Swept Wings: Hybrid Design Process, Years 1 and 2

    Science.gov (United States)

    Fujiwara, Gustavo; Bragg, Mike; Triphahn, Chris; Wiberg, Brock; Woodard, Brian; Loth, Eric; Malone, Adam; Paul, Bernard; Pitera, David; Wilcox, Pete; hide

    2017-01-01

    This report presents the key results from the first two years of a program to develop experimental icing simulation capabilities for full-scale swept wings. This investigation was undertaken as a part of a larger collaborative research effort on ice accretion and aerodynamics for large-scale swept wings. Ice accretion and the resulting aerodynamic effect on large-scale swept wings presents a significant airplane design and certification challenge to air frame manufacturers, certification authorities, and research organizations alike. While the effect of ice accretion on straight wings has been studied in detail for many years, the available data on swept-wing icing are much more limited, especially for larger scales.

  10. Numerical Study on the Effect of Swept Blade on the Aerodynamic Performance of Wind Turbine at High Tip Speed Ratio

    International Nuclear Information System (INIS)

    Zuo, H M; Liu, C; Yang, H; Wang, F

    2016-01-01

    The current situation is that the development of high speed wind energy saturates gradually, therefore, it is highly necessary to develop low speed wind energy. This paper, based on a specific straight blade and by using Isight, a kind of multidiscipline optimization software, which integrates ICEM (Integrated Computer Engineering and Manufacturing) and CFD (Computational Fluid Dynamics) software, optimizes the blade stacking line (the centers of airfoil from blade root to tip) and acquires the optimization swept blade shape. It is found that power coefficient C p of swept blade is 3.2% higher than that of straight blade at the tip speed ratio of 9.82, that the thrust of swept blade receives is obviously less than that of straight blade. Inflow angle of attack and steam line on the suction of the swept and straight blade are also made a comparison. (paper)

  11. Vertical zonation and seed germination indices of chromium resistant cellulolytic and nitrogen fixing bacteria from a chronically metal exposed land area

    International Nuclear Information System (INIS)

    Aslam, S.; Qazi, J.I.

    2014-01-01

    Twenty eight cellulolytic and 25 nitrogen fixing bacteria were isolated from 20, 40 and 60 cm depths of the chromium contaminated land area. The cellulolytic as well as nitrogen fixing microbial communities in soil profiles were dominated by genus Bacillus. More diverse nitrogen fixing bacterial isolates belonging to different genera Paenibacillus, Corynebacterium and Pseudomonas were observed as compared to cellulolytic bacterial community. Majority of the cellulolytic bacteria were found inhabitants of 20 cm soil layer while 40 cm depth was the preferred zone for the nitrogen fixing bacteria. Screening of the bacterial isolates for chromium resistance showed that isolates designated as ASK15 and ASK16 were able to resist up to 1800 mg/l of chromium while the nitrogen fixing isolates which offered a maximum resistant level up to 1650 mg/l of chromium were ASNt10 and ASNS13. Nitrogen fixing isolates enhanced seed germination by 33% and expressed efficient nitrogenase activity up to 0.80 (C/sub 2/H/sub 2/ nmol/ml/hr). Growth promoting assay proved ASNt10 a potential isolate which produced 90 meu g/ml of indoleacetic acid (IAA). Though cellulolytic isolates did not affect seed germination, a significant influence on root length similar to that of ASNt10 and ASNS13 with nearly 5-fold increase in comparison with uninoculated control was observed. The isolates ASK15, ASK16 were identified as Bacillus cereus while ASNt10 and ASNS13 as Paenibacillus barcinonensis and Bacillus megaterium, respectively. (author)

  12. Vertically building Zn2SnO4 nanowire arrays on stainless steel mesh toward fabrication of large-area, flexible dye-sensitized solar cells.

    Science.gov (United States)

    Li, Zhengdao; Zhou, Yong; Bao, Chunxiong; Xue, Guogang; Zhang, Jiyuan; Liu, Jianguo; Yu, Tao; Zou, Zhigang

    2012-06-07

    Zn(2)SnO(4) nanowire arrays were for the first time grown onto a stainless steel mesh (SSM) in a binary ethylenediamine (En)/water solvent system using a solvothermal route. The morphology evolution following this reaction was carefully followed to understand the formation mechanism. The SSM-supported Zn(2)SnO(4) nanowire was utilized as a photoanode for fabrication of large-area (10 cm × 5 cm size as a typical sample), flexible dye-sensitized solar cells (DSSCs). The synthesized Zn(2)SnO(4) nanowires exhibit great bendability and flexibility, proving potential advantage over other metal oxide nanowires such as TiO(2), ZnO, and SnO(2) for application in flexible solar cells. Relative to the analogous Zn(2)SnO(4) nanoparticle-based flexible DSSCs, the nanowire geometry proves to enhance solar energy conversion efficiency through enhancement of electron transport. The bendable nature of the DSSCs without obvious degradation of efficiency and facile scale up gives the as-made flexible solar cell device potential for practical application.

  13. Field-swept pulsed electron paramagnetic resonance of Cr3+-doped ZBLAN fluoride glass

    International Nuclear Information System (INIS)

    Drew, S.C.; Pilbrow, J.R.; Newman, P.J.; MacFarlane, D.R.

    2001-01-01

    Field-swept pulsed electron paramagnetic resonance (EPR) spectra of a ZBLAN fluoride glass doped with a low concentration of Cr 3+ are obtained using echo-detected EPR and hole-burning free induction decay detection. We review the utility of the pulsed EPR technique in generating field-swept EPR spectra, as well as some of the distorting effects that are peculiar to the pulsed detection method. The application of this technique to Cr 3+ -doped ZBLAN reveals that much of the broad resonance extending from g eff =5.1 to g eff =1.97, characteristic of X-band continuous wave EPR of Cr 3+ in glasses, is absent. We attribute this largely to the variation in nutation frequencies across the spectrum that result from sites possessing large fine structure interactions. The description of the spin dynamics of such sites is complicated and we discuss some possible approaches to the simulation of the pulsed EPR spectra. (author)

  14. Off-axis full-field swept-source optical coherence tomography using holographic refocusing

    Science.gov (United States)

    Hillmann, Dierck; Franke, Gesa; Hinkel, Laura; Bonin, Tim; Koch, Peter; Hüttmann, Gereon

    2013-03-01

    We demonstrate a full-field swept-source OCT using an off-axis geometry of the reference illumination. By using holographic refocusing techniques, a uniform lateral resolution is achieved over the measurement depth of approximately 80 Rayleigh lengths. Compared to a standard on-axis setup, artifacts and autocorrelation signals are suppressed and the measurement depth is doubled by resolving the complex conjugate ambiguity. Holographic refocusing was done efficiently by Fourier-domain resampling as demonstrated before in inverse scattering and holoscopy. It allowed to reconstruct a complete volume with about 10μm resolution over the complete measurement depth of more than 10mm. Off-axis full-field swept-source OCT enables high measurement depths, spanning many Rayleigh lengths with reduced artifacts.

  15. Rapid-swept CW cavity ring-down laser spectroscopy for carbon isotope analysis

    International Nuclear Information System (INIS)

    Tomita, Hideki; Watanabe, Kenichi; Takiguchi, Yu; Kawarabayashi, Jun; Iguchi, Tetsuo

    2006-01-01

    With the aim of developing a portable system for an in field isotope analysis, we investigate an isotope analysis based on rapid-swept CW cavity ring-down laser spectroscopy, in which the concentration of a chemical species is derived from its photo absorbance. Such a system can identify the isotopomer and still be constructed as a quite compact system. We have made some basic experimental measurements of the overtone absorption lines of carbon dioxide ( 12 C 16 O 2 , 13 C 16 O 2 ) by rapid-swept cavity ring-down spectroscopy with a CW infrared diode laser at 6,200 cm -1 (1.6 μm). The isotopic ratio has been obtained as (1.07±0.13)x10 -2 , in good agreement with the natural abundance within experimental uncertainty. The detection sensitivity in absorbance has been estimated to be 3x10 -8 cm -1 . (author)

  16. NASA,FAA,ONERA Swept-Wing Icing and Aerodynamics: Summary of Research and Current Status

    Science.gov (United States)

    Broeren, Andy

    2015-01-01

    NASA, FAA, ONERA, and other partner organizations have embarked on a significant, collaborative research effort to address the technical challenges associated with icing on large scale, three-dimensional swept wings. These are extremely complex phenomena important to the design, certification and safe operation of small and large transport aircraft. There is increasing demand to balance trade-offs in aircraft efficiency, cost and noise that tend to compete directly with allowable performance degradations over an increasing range of icing conditions. Computational fluid dynamics codes have reached a level of maturity that they are being proposed by manufacturers for use in certification of aircraft for flight in icing. However, sufficient high-quality data to evaluate their performance on iced swept wings are not currently available in the public domain and significant knowledge gaps remain.

  17. Simple and versatile long range swept source for optical coherence tomography applications

    International Nuclear Information System (INIS)

    Bräuer, Bastian; Lippok, Norman; Murdoch, Stuart G; Vanholsbeeck, Frédérique

    2015-01-01

    We present a versatile long coherence length swept-source laser design for optical coherence tomography applications. This design consists of a polygonal spinning mirror and an optical gain chip in a modified Littman–Metcalf cavity. A narrowband intra-cavity filter is implemented through multiple passes off a diffraction grating set at grazing incidence. The key advantage of this design is that it can be readily adapted to any wavelength regions for which broadband gain chips are available. We demonstrate this by implementing sources at 1650 nm, 1550 nm, 1310 nm and 1050 nm. In particular, we present a 1310 nm swept source laser with 24 mm coherence length, 95 nm optical bandwidth, 2 kHz maximum sweep frequency and 7.5 mW average output power. These parameters make it a suitable source for the imaging of biological samples. (paper)

  18. A new aeroelastic model for composite rotor blades with straight and swept tips

    Science.gov (United States)

    Yuan, Kuo-An; Friedmann, Peretz P.; Venkatesan, Comandur

    1992-01-01

    An analytical model for predicting the aeroelastic behavior of composite rotor blades with straight and swept tips is presented. The blade is modeled by beam type finite elements along the elastic axis. A single finite element is used to model the swept tip. The nonlinear equations of motion for the finite element model are derived using Hamilton's principle and based on a moderate deflection theory and accounts for: arbitrary cross-sectional shape, pretwist, generally anisotropic material behavior, transverse shears and out-of-plane warping. Numerical results illustrating the effects of tip sweep, anhedral and composite ply orientation on blade aeroelastic behavior are presented. Tip sweep can induce aeroelastic instability by flap-twist coupling. Tip anhedral causes lag-torsion and flap-axial couplings, however, its effects on blade stability is less pronounced than the effect due to sweep. Composite ply orientation has a substantial effect on blade stability.

  19. Analysis, Synthesis, and Classification of Nonlinear Systems Using Synchronized Swept-Sine Method for Audio Effects

    Directory of Open Access Journals (Sweden)

    Novak Antonin

    2010-01-01

    Full Text Available A new method of identification, based on an input synchronized exponential swept-sine signal, is used to analyze and synthesize nonlinear audio systems like overdrive pedals for guitar. Two different pedals are studied; the first one exhibiting a strong influence of the input signal level on its input/output law and the second one exhibiting a weak influence of this input signal level. The Synchronized Swept Sine method leads to a Generalized Polynomial Hammerstein model equivalent to the pedals under test. The behaviors of both pedals are illustrated through model-based resynthesized signals. Moreover, it is also shown that this method leads to a criterion allowing the classification of the nonlinear systems under test, according to the influence of the input signal levels on their input/output law.

  20. Study of Flow Patterns in Radial and Back Swept Turbine Rotor under Design and Off-Design Conditions

    OpenAIRE

    Samip Shah; Salim Channiwala; Digvijay Kulshreshtha; Gaurang Chaudhari

    2016-01-01

    Paper details the numerical investigation of flow patterns in a conventional radial turbine compared with a back swept design for same application. The blade geometry of a designed turbine from a 25kW micro gas turbine was used as a baseline. A back swept blade was subsequently designed for the rotor, which departed from the conventional radial inlet blade angle to incorporate up to 25° inlet blade angle. A comparative numerical analysis between the two geometries is presented. While opera...

  1. Investigation of vertical and horizontal transport processes and their influence on the concentration of aerosols and ozone over the greater Berlin area

    Science.gov (United States)

    Reimer, E.; Kerschbaumer, A.; Beekmann, M.; Neißner, F.

    2003-04-01

    Urban emissions of particulate matter and precursors of ozone are very important in relation to the EU-council directives and national pollution abatement strategies. Knowledge about the contribution of anthropogenic urban sources and about long range transport of polluted air to local concentrations is needed for any reduction strategy. Thus, within the German Atmospheric Research Program AFO2000 a project has been started to investigate the formation and transport of PM10/PM2.5 in the greater Berlin area by sampling and analysing PM, using LIDAR as well as physico-chemical measurements to determine density, partical size distribution and chemical composition of the aerosol. Participants are: Freie Universität Berlin, Institute for Meteorology BTU Cottbus, Air Chemistry Department Elight Laser Systems GmbH Freie Universität Berlin, Physics Department Environmental Administration, Berlin Government with an additional PM campaign Measurements at central Berlin monitoring stations exceed standard PM10 tresholds. Therefore, it is important to get a better knowledge about PM sources within and outside the city. Long term applications of the chemical transport model with an aerosol-module REM3/Calgrid is used to explain transport, formation and deposition processes. Backward and forward trajectories are used to determine source/receptor relationships between the observations and European wide emission maps for ozone, precursors and PM10 and PM2,5 by correlation between observed primary aerosols in Berlin and possible sources. The measurements obtained within the project are also used to validate REM3/Calgrid with special respect to SO4, NO3, NH4 and ozone precursors.

  2. Vertical leaf mass per area gradient of mature sugar maple reflects both height-driven increases in vascular tissue and light-driven increases in palisade layer thickness.

    Science.gov (United States)

    Coble, Adam P; Cavaleri, Molly A

    2017-10-01

    A key trait used in canopy and ecosystem function modeling, leaf mass per area (LMA), is influenced by changes in both leaf thickness and leaf density (LMA = Thickness × Density). In tall trees, LMA is understood to increase with height through two primary mechanisms: (i) increasing palisade layer thickness (and thus leaf thickness) in response to light and/or (ii) reduced cell expansion and intercellular air space in response to hydrostatic constraints, leading to increased leaf density. Our objective was to investigate within-canopy gradients in leaf anatomical traits in order to understand environmental factors that influence leaf morphology in a sugar maple (Acer saccharum Marshall) forest canopy. We teased apart the effects of light and height on anatomical traits by sampling at exposed and closed canopies that had different light conditions at similar heights. As expected, palisade layer thickness responded strongly to cumulative light exposure. Mesophyll porosity, however, was weakly and negatively correlated with light and height (i.e., hydrostatic gradients). Reduced mesophyll porosity was not likely caused by limitations on cell expansion; in fact, epidermal cell width increased with height. Palisade layer thickness was better related to LMA, leaf density and leaf thickness than was mesophyll porosity. Vein diameter and fraction of vascular tissue also increased with height and LMA, density and thickness, revealing that greater investment in vascular and support tissue may be a third mechanism for increased LMA with height. Overall, decreasing mesophyll porosity with height was likely due to palisade cells expanding into the available air space and also greater investments in vascular and support tissue, rather than a reduction of cell expansion due to hydrostatic constraints. Our results provide evidence that light influences both palisade layer thickness and mesophyll porosity and indicate that hydrostatic gradients influence leaf vascular and support

  3. High-Speed Measurements on a Swept-Back Wing (Sweepback Angle phi = 35 Deg)

    Science.gov (United States)

    Goethert, B.

    1947-01-01

    In the following, high-speed measurements on a swept-back wing are reported. The curves of lift, moment, and drag have been determined up to Mach numbers of M = 0.87, and they are compared to a rectangular wing. Through measurements of the total-head loss behind the wing and through schlieren pictures, an insight into the formation of the compression shock at high Mach numbers has been obtained.

  4. Imaging choroidal neovascular membrane using en face swept-source optical coherence tomography angiography

    Directory of Open Access Journals (Sweden)

    Moussa M

    2017-10-01

    Full Text Available Magdy Moussa,1,2 Mahmoud Leila,3 Hagar Khalid1,2 1Ophthalmology Department, Faculty of Medicine, Tanta University, Tanta, Egypt; 2MEDIC Eye Center, Tanta, Egypt; 3Retina Department, Research Institute of Ophthalmology, Giza, Egypt Purpose: The aim of this study was to assess the efficacy of swept-source optical coherence tomography angiography (SS-OCTA in delineating the morphology of choroidal neovascular membrane (CNV. Patients and methods: This was a retrospective observational case series reviewing clinical data and fundus fluorescein angiography (FFA, swept-source optical coherence tomography (SS-OCT, and SS-OCTA images of patients with CNV and comparing the findings. The swept-source technology enables deeper penetration and superior axial resolution. The incorporated blood flow detection algorithm, optical coherence tomography angiography ratio analysis (OCTARA, enables visualization of CNV in vivo without the need for dye injection. Results: The study included 136 eyes of 105 patients. Active lesions on SS-OCTA images showed increased capillary density, extensive arborization, vascular anastomosis and looping, and peri-lesional hollow. Inactive lesions showed decreased capillary density, presence of large linear vessels, and presence of feeder vessels supplying the CNV. We detected positive correlation between SS-OCTA, FFA, and SS-OCT images in 97% of eyes. In the remaining 3%, SS-OCTA confirmed the absence of CNV, whereas FFA and SS-OCT either were inconclusive in the diagnosis of CNV or yielded false-positive results. Conclusion: SS-OCT and SS-OCTA represent a reproducible risk-free analog for FFA in imaging CNV. SS-OCTA is particularly versatile in cases where FFA and SS-OCT are inconclusive. Keywords: swept-source OCT, OCT angiography, imaging of CNV, OCTARA algorithm

  5. ENERGETIC EXTREMES IN A HOSTILE HABITAT: FISH LOCOMOTION ON WAVE-SWEPT CORAL REEFS

    DEFF Research Database (Denmark)

    Steffensen, John Fleng

    2010-01-01

    , and wing-like fins that generate lift-based thrust at high speed. Literally flying underwater, Stethojulis and other winged-fin species are the most abundant fish in wave-swept coral reef habitats. We discuss the extreme swimming performance of these reef fishes within the context of other non......-scombrid and scombrid fishes, and illustrate how such performance has contributed to their domination of shallow coral reef habitats worldwide....

  6. The use of swept-charge devices in planetary analogue X-ray fluorescence studies

    International Nuclear Information System (INIS)

    Walker, T E; Smith, D R

    2012-01-01

    The Chandrayaan-1 X-ray Spectrometer (C1XS) was launched onboard the Indian Space Research Organisation (ISRO) Chandrayaan-1 lunar mission in October 2008. The instrument consisted of 24 swept-charge device (SCD) silicon X-ray detectors providing a total collecting area of ∼ 24 cm 2 , corresponding to a 14° field of view (FWHM), with the ability to measure X-rays from 0.8–10 keV. One algorithm used to analyse the C1XS flight data was developed at Rutherford Appleton Laboratory (RAL) to convert the raw X-ray flux data into elemental ratios and abundances to make geological interpretations about the lunar surface. Laboratory X-ray fluorescence (XRF) data were used to validate the RAL algorithm, with previous studies investigating how the measured XRF flux varies with target surface characteristics including grain size and roughness. Evidence for a grain-size effect was observed in the data, the XRF line intensity generally decreasing with increasing sample grain size, dependent on the relative abundance of elemental components. This paper presents a subsequent study using more homogeneous samples made from mixtures of MgO, Al 2 O 3 and SiO 2 powders, all of grain size < 44 μm, across a broader range of mixture ratios and at a higher level of X-ray flux data in order to further validate the RAL algorithm. For the majority of the C1XS flight data analysed so far with the RAL algorithm, the corresponding lunar ground tracks have been generally basaltic, laboratory verification of the algorithm having been primarily conducted using basaltic lunar regolith simulant (JSC-1A) XRF data. This paper also presents results from tests on a terrestrial anorthosite sample, more relevant to the anorthositic lunar highlands, from where the remaining C1XS lunar dataset derives. The operation of the SCD, the XRF test facility, sample preparation and collected XRF spectra are discussed in this paper.

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

    Directory of Open Access Journals (Sweden)

    Dewang Angmo

    2016-01-01

    Full Text Available 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.

  8. Aeroelasticity and structural optimization of composite helicopter rotor blades with swept tips

    Science.gov (United States)

    Yuan, K. A.; Friedmann, P. P.

    1995-01-01

    This report describes the development of an aeroelastic analysis capability for composite helicopter rotor blades with straight and swept tips, and its application to the simulation of helicopter vibration reduction through structural optimization. A new aeroelastic model is developed in this study which is suitable for composite rotor blades with swept tips in hover and in forward flight. The hingeless blade is modeled by beam type finite elements. A single finite element is used to model the swept tip. Arbitrary cross-sectional shape, generally anisotropic material behavior, transverse shears and out-of-plane warping are included in the blade model. The nonlinear equations of motion, derived using Hamilton's principle, are based on a moderate deflection theory. Composite blade cross-sectbnal properties are calculated by a separate linear, two-dimensional cross section analysis. The aerodynamic loads are obtained from quasi-steady, incompressible aerodynamics, based on an implicit formulation. The trim and steady state blade aeroelastic response are solved in a fully coupled manner. In forward flight, where the blade equations of motion are periodic, the coupled trim-aeroelastic response solution is obtained from the harmonic balance method. Subsequently, the periodic system is linearized about the steady state response, and its stability is determined from Floquet theory.

  9. Aeroelastic modeling of composite rotor blades with straight and swept tips

    Science.gov (United States)

    Yuan, Kuo-An; Friedmann, Peretz P.; Venkatesan, Comandur

    1992-01-01

    This paper presents an analytical study of the aeroelastic behavior of composite rotor blades with straight and swept tips. The blade is modeled by beam type finite elements. A single finite element is used to model the swept tip. The nonlinear equations of motion for the FEM are derived using Hamilton's principle and based on a moderate deflection theory and accounts for: arbitrary cross-sectional shape, pretwist, generally anisotropic material behavior, transverse shears and out-of-plane warping. Numerical results illustrating the effects of tip sweep, anhedral and composite ply orientation on blade aeroelastic behavior are presented. It is shown that composite ply orientation has a substantial effect on blade stability. At low thrust conditions, certain ply orientations can cause instability in the lag mode. The flap-torsion coupling associated with tip sweep can also induce aeroelastic instability in the blade. This instability can be removed by appropriate ply orientation in the composite construction. These results illustrate the inherent potential for aeroelastic tailoring present in composite rotor blades with swept tips, which still remains to be exploited in the design process.

  10. 2.5-D modelling of rime ice accretion on a swept airfoil

    International Nuclear Information System (INIS)

    Szilder, K.; Lozowski, E.P.

    2004-01-01

    In this paper, we present a three-dimensional morphogenetic model which simulates discrete rime ice accretion structures forming on a swept airfoil. Rime is an ice deposit caused by the impingement and freezing of supercooled cloud droplets at accretion temperatures below 0 o C. Depending on conditions, the droplets may freeze as spheres or deform on the surface, but for rime to form, surface liquid flow is limited or non-existent. In the model, roughness elements that develop initially on the wing surface evolve into rime feathers and other complex, three-dimensional structures. On swept wings, these resemble the so-called 'lobster tails' or 'scallops' that are observed in wind tunnels and in flight. We show the results of sensitivity tests, performed as a function of two model parameters: sweep angle and freezing range parameter. Our exploratory research has shown that the model predicts realistic-looking, three-dimensional ice structures on swept wings. This capability does not exist in current in-flight ice accretion models. (author)

  11. 2.5-D modelling of rime ice accretion on a swept airfoil

    Energy Technology Data Exchange (ETDEWEB)

    Szilder, K. [National Research Council of Canada, Inst. for Aerospace Research, Ottawa, Ontario (Canada)]. E-mail: Krzysztof.Szilder@nrc-cnrc.gc.ca; Lozowski, E.P. [Univ. of Alberta, Dept. of Earth and Atmospheric Sciences, Edmonton, Alberta (Canada)

    2004-07-01

    In this paper, we present a three-dimensional morphogenetic model which simulates discrete rime ice accretion structures forming on a swept airfoil. Rime is an ice deposit caused by the impingement and freezing of supercooled cloud droplets at accretion temperatures below 0{sup o}C. Depending on conditions, the droplets may freeze as spheres or deform on the surface, but for rime to form, surface liquid flow is limited or non-existent. In the model, roughness elements that develop initially on the wing surface evolve into rime feathers and other complex, three-dimensional structures. On swept wings, these resemble the so-called 'lobster tails' or 'scallops' that are observed in wind tunnels and in flight. We show the results of sensitivity tests, performed as a function of two model parameters: sweep angle and freezing range parameter. Our exploratory research has shown that the model predicts realistic-looking, three-dimensional ice structures on swept wings. This capability does not exist in current in-flight ice accretion models. (author)

  12. Vertical axis wind turbines

    Science.gov (United States)

    Krivcov, Vladimir [Miass, RU; Krivospitski, Vladimir [Miass, RU; Maksimov, Vasili [Miass, RU; Halstead, Richard [Rohnert Park, CA; Grahov, Jurij [Miass, RU

    2011-03-08

    A vertical axis wind turbine is described. The wind turbine can include a top ring, a middle ring and a lower ring, wherein a plurality of vertical airfoils are disposed between the rings. For example, three vertical airfoils can be attached between the upper ring and the middle ring. In addition, three more vertical airfoils can be attached between the lower ring and the middle ring. When wind contacts the vertically arranged airfoils the rings begin to spin. By connecting the rings to a center pole which spins an alternator, electricity can be generated from wind.

  13. Vertical variability of aerosol single-scattering albedo and equivalent black carbon concentration based on in-situ and remote sensing techniques during the iAREA campaigns in Ny-Ålesund

    Science.gov (United States)

    Markowicz, K. M.; Ritter, C.; Lisok, J.; Makuch, P.; Stachlewska, I. S.; Cappelletti, D.; Mazzola, M.; Chilinski, M. T.

    2017-09-01

    This work presents a methodology for obtaining vertical profiles of aerosol single scattering properties based on a combination of different measurement techniques. The presented data were obtained under the iAREA (Impact of absorbing aerosols on radiative forcing in the European Arctic) campaigns conducted in Ny-Ålesund (Spitsbergen) during the spring seasons of 2015-2017. The retrieval uses in-situ observations of black carbon concentration and absorption coefficient measured by a micro-aethalometer AE-51 mounted onboard a tethered balloon, as well as remote sensing data obtained from sun photometer and lidar measurements. From a combination of the balloon-borne in-situ and the lidar data, we derived profiles of single scattering albedo (SSA) as well as absorption, extinction, and aerosol number concentration. Results have been obtained in an altitude range from about 400 m up to 1600 m a.s.l. and for cases with increased aerosol load during the Arctic haze seasons of 2015 and 2016. The main results consist of the observation of increasing values of equivalent black carbon (EBC) and absorption coefficient with altitude, and the opposite trend for aerosol concentration for particles larger than 0.3 μm. SSA was retrieved with the use of lidar Raman and Klett algorithms for both 532 and 880 nm wavelengths. In most profiles, SSA shows relatively high temporal and altitude variability. Vertical variability of SSA computed from both methods is consistent; however, some discrepancy is related to Raman retrieval uncertainty and absorption coefficient estimation from AE-51. Typically, very low EBC concentration in Ny-Ålesund leads to large error in the absorbing coefficient. However, SSA uncertainty for both Raman and Klett algorithms seems to be reasonable, e.g. SSA of 0.98 and 0.95 relate to an error of ±0.01 and ± 0.025, respectively.

  14. Long axial imaging range using conventional swept source lasers in optical coherence tomography via re-circulation loops

    Science.gov (United States)

    Bradu, Adrian; Jackson, David A.; Podoleanu, Adrian

    2018-03-01

    Typically, swept source optical coherence tomography (SS-OCT) imaging instruments are capable of a longer axial range than their camera based (CB) counterpart. However, there are still various applications that would take advantage for an extended axial range. In this paper, we propose an interferometer configuration that can be used to extend the axial range of the OCT instruments equipped with conventional swept-source lasers up to a few cm. In this configuration, the two arms of the interferometer are equipped with adjustable optical path length rings. The use of semiconductor optical amplifiers in the two rings allows for compensating optical losses hence, multiple paths depth reflectivity profiles (Ascans) can be combined axially. In this way, extremely long overall axial ranges are possible. The use of the recirculation loops produces an effect equivalent to that of extending the coherence length of the swept source laser. Using this approach, the achievable axial imaging range in SS-OCT can reach values well beyond the limit imposed by the coherence length of the laser, to exceed in principle many centimeters. In the present work, we demonstrate axial ranges exceeding 4 cm using a commercial swept source laser and reaching 6 cm using an "in-house" swept source laser. When used in a conventional set-up alone, both these lasers can provide less than a few mm axial range.

  15. Can Probability Maps of Swept-Source Optical Coherence Tomography Predict Visual Field Changes in Preperimetric Glaucoma?

    Science.gov (United States)

    Lee, Won June; Kim, Young Kook; Jeoung, Jin Wook; Park, Ki Ho

    2017-12-01

    To determine the usefulness of swept-source optical coherence tomography (SS-OCT) probability maps in detecting locations with significant reduction in visual field (VF) sensitivity or predicting future VF changes, in patients with classically defined preperimetric glaucoma (PPG). Of 43 PPG patients, 43 eyes were followed-up on every 6 months for at least 2 years were analyzed in this longitudinal study. The patients underwent wide-field SS-OCT scanning and standard automated perimetry (SAP) at the time of enrollment. With this wide-scan protocol, probability maps originating from the corresponding thickness map and overlapped with SAP VF test points could be generated. We evaluated the vulnerable VF points with SS-OCT probability maps as well as the prevalence of locations with significant VF reduction or subsequent VF changes observed in the corresponding damaged areas of the probability maps. The vulnerable VF points were shown in superior and inferior arcuate patterns near the central fixation. In 19 of 43 PPG eyes (44.2%), significant reduction in baseline VF was detected within the areas of structural change on the SS-OCT probability maps. In 16 of 43 PPG eyes (37.2%), subsequent VF changes within the areas of SS-OCT probability map change were observed over the course of the follow-up. Structural changes on SS-OCT probability maps could detect or predict VF changes using SAP, in a considerable number of PPG eyes. Careful comparison of probability maps with SAP results could be useful in diagnosing and monitoring PPG patients in the clinical setting.

  16. Subgingival calculus imaging based on swept-source optical coherence tomography

    Science.gov (United States)

    Hsieh, Yao-Sheng; Ho, Yi-Ching; Lee, Shyh-Yuan; Lu, Chih-Wei; Jiang, Cho-Pei; Chuang, Ching-Cheng; Wang, Chun-Yang; Sun, Chia-Wei

    2011-07-01

    We characterized and imaged dental calculus using swept-source optical coherence tomography (SS-OCT). The refractive indices of enamel, dentin, cementum, and calculus were measured as 1.625 +/- 0.024, 1.534 +/- 0.029, 1.570 +/- 0.021, and 2.097 +/- 0.094, respectively. Dental calculus leads strong scattering properties, and thus, the region can be identified from enamel with SS-OCT imaging. An extracted human tooth with calculus is covered with gingiva tissue as an in vitro sample for tomographic imaging.

  17. Quantitative phase imaging of living cells with a swept laser source

    Science.gov (United States)

    Chen, Shichao; Zhu, Yizheng

    2016-03-01

    Digital holographic phase microscopy is a well-established quantitative phase imaging technique. However, interference artifacts from inside the system, typically induced by elements whose optical thickness are within the source coherence length, limit the imaging quality as well as sensitivity. In this paper, a swept laser source based technique is presented. Spectra acquired at a number of wavelengths, after Fourier Transform, can be used to identify the sources of the interference artifacts. With proper tuning of the optical pathlength difference between sample and reference arms, it is possible to avoid these artifacts and achieve sensitivity below 0.3nm. Performance of the proposed technique is examined in live cell imaging.

  18. Vertical guidance of shearers

    International Nuclear Information System (INIS)

    Pocock, J.

    1985-01-01

    Mining Engineers have always been aware of the basic need to avoid contamination of the mined product, by controlling the cutting horizon at the coal face. The ability to maintain the optimum cutting horizon results in more effective roof control and ensures a safer and more efficient working environment, for men and machinery. The cost of treatment in the surface coal preparation plant is reduced. Transportation through the total mine system of material finally destined for the spoil heap is minimised. A reduction in product contamination is achieved and makes more effective use of the mine capacity. These benefits make possible significant improvements in productivity and financial returns. Exploitation of micro computer based systems has enabled the successful development of equipment which employs sensors to detect the very low natural gamma radiation from roof strata; to determine and allow control of the position of the cut relative to the roof and floor. This paper reviews the experience gained by the National Coal Board, particularly in South Yorkshire Area, with the vertical steering of ranging drum shearers. It outlines the benefits and considers the future for this technology and its contribution to total coal face automation

  19. Performance, Stability, and Control Investigation at Mach Numbers from 0.4 to 0.9 of a Model of the "Swallow" with Outer Wing Panels Swept 25 degree with and without Power Simulation

    Science.gov (United States)

    Runckel, Jack F.; Schmeer, James W.; Cassetti, Marlowe D.

    1960-01-01

    An investigation of the performance, stability, and control characteristics of a variable-sweep arrow-wing model (the "Swallow") with the outer wing panels swept 25 deg has been conducted in the Langley 16-foot transonic tunnel. The wing was uncambered and untwisted and had RAE 102 airfoil sections with a thickness-to-chord ratio of 0.14 normal to the leading edge. Four outboard engines located above and below the wing provided propulsive thrust, and, by deflecting in the pitch direction and rotating in the lateral plane, also produced control forces. A pair of swept lateral fins and a single vertical fin were mounted on each engine nacelle to provide aerodynamic stability and control. Jets-off data were obtained with flow-through nacelles, stimulating the effects of inlet flow; jet thrust and hot-jet interference effects were obtained with faired-nose nacelles housing hydrogen peroxide gas generators. Six-component force and moment data were obtained through a Mach number range of 0.40 to 0.90 at angles of attack and angles of sideslip from 0 deg to 15 deg. Longitudinal, directional, and lateral control were obtained by deflecting the nacelle-fin combinations as elevators, rudders, and ailerons at several fixed angles for each control.

  20. Agreement of Anterior Segment Parameters Obtained From Swept-Source Fourier-Domain and Time-Domain Anterior Segment Optical Coherence Tomography.

    Science.gov (United States)

    Chansangpetch, Sunee; Nguyen, Anwell; Mora, Marta; Badr, Mai; He, Mingguang; Porco, Travis C; Lin, Shan C

    2018-03-01

    To assess the interdevice agreement between swept-source Fourier-domain and time-domain anterior segment optical coherence tomography (AS-OCT). Fifty-three eyes from 41 subjects underwent CASIA2 and Visante OCT imaging. One hundred eighty-degree axis images were measured with the built-in two-dimensional analysis software for the swept-source Fourier-domain AS-OCT (CASIA2) and a customized program for the time-domain AS-OCT (Visante OCT). In both devices, we examined the angle opening distance (AOD), trabecular iris space area (TISA), angle recess area (ARA), anterior chamber depth (ACD), anterior chamber width (ACW), and lens vault (LV). Bland-Altman plots and intraclass correlation (ICC) were performed. Orthogonal linear regression assessed any proportional bias. ICC showed strong correlation for LV (0.925) and ACD (0.992) and moderate agreement for ACW (0.801). ICC suggested good agreement for all angle parameters (0.771-0.878) except temporal AOD500 (0.743) and ARA750 (nasal 0.481; temporal 0.481). There was a proportional bias in nasal ARA750 (slope 2.44, 95% confidence interval [CI]: 1.95-3.18), temporal ARA750 (slope 2.57, 95% CI: 2.04-3.40), and nasal TISA500 (slope 1.30, 95% CI: 1.12-1.54). Bland-Altman plots demonstrated in all measured parameters a minimal mean difference between the two devices (-0.089 to 0.063); however, evidence of constant bias was found in nasal AOD250, nasal AOD500, nasal AOD750, nasal ARA750, temporal AOD500, temporal AOD750, temporal ARA750, and ACD. Among the parameters with constant biases, CASIA2 tends to give the larger numbers. Both devices had generally good agreement. However, there were proportional and constant biases in most angle parameters. Thus, it is not recommended that values be used interchangeably.

  1. Conical Euler solution for a highly-swept delta wing undergoing wing-rock motion

    Science.gov (United States)

    Lee, Elizabeth M.; Batina, John T.

    1990-01-01

    Modifications to an unsteady conical Euler code for the free-to-roll analysis of highly-swept delta wings are described. The modifications involve the addition of the rolling rigid-body equation of motion for its simultaneous time-integration with the governing flow equations. The flow solver utilized in the Euler code includes a multistage Runge-Kutta time-stepping scheme which uses a finite-volume spatial discretization on an unstructured mesh made up of triangles. Steady and unsteady results are presented for a 75 deg swept delta wing at a freestream Mach number of 1.2 and an angle of attack of 30 deg. The unsteady results consist of forced harmonic and free-to-roll calculations. The free-to-roll case exhibits a wing rock response produced by unsteady aerodynamics consistent with the aerodynamics of the forced harmonic results. Similarities are shown with a wing-rock time history from a low-speed wind tunnel test.

  2. Optical frequency-domain reflectometry using multiple wavelength-swept elements of a DFB laser array

    Science.gov (United States)

    DiLazaro, Tom; Nehmetallah, Georges

    2017-02-01

    Coherent optical frequency-domain reflectometry (C-OFDR) is a distance measurement technique with significant sensitivity and detector bandwidth advantages over normal time-of-flight methods. Although several swept-wavelength laser sources exist, many exhibit short coherence lengths, or require precision mechanical tuning components. Semiconductor distributed feedback lasers (DFBs) are advantageous as a mid-to-long range OFDR source because they exhibit a narrow linewidth and can be rapidly tuned simply via injection current. However, the sweep range of an individual DFB is thermally limited. Here, we present a novel high-resolution OFDR system that uses a compact, monolithic 12-element DFB array to create a continuous, gap-free sweep over a wide wavelength range. Wavelength registration is provided by the incorporation of a HCN gas cell and reference interferometer. The wavelength-swept spectra of the 12 DFBs are combined in post-processing to achieve a continuous total wavelength sweep of more than 40 nm (5.4 THz) in the telecommunications C-Band range.

  3. Validation of a Residual Stress Measurement Method by Swept High-Frequency Eddy Currents

    International Nuclear Information System (INIS)

    Lee, C.; Shen, Y.; Lo, C. C. H.; Nakagawa, N.

    2007-01-01

    This paper reports on a swept high-frequency eddy current (SHFEC) measurement method developed for electromagnetic nondestructive characterization of residual stresses in shot peened aerospace materials. In this approach, we regard shot-peened surfaces as modified surface layers of varying conductivity, and determine the conductivity deviation profile by inversion of the SHFEC data. The SHFEC measurement system consists of a pair of closely matched printed-circuit-board coils driven by laboratory instrument under software control. This provides improved sensitivity and high frequency performance compared to conventional coils, so that swept frequency EC measurements up to 50 MHz can be made to achieve the smallest skin depth of 80 μm for nickel-based superalloys. We devised a conductivity profile inversion procedure based on the laterally uniform multi-layer theory of Cheng, Dodd and Deeds. The main contribution of this paper is the methodology validation. Namely, the forward and inverse models were validated against measurements on artificial layer specimens consisting of metal films with different conductivities placed on a metallic substrate. The inversion determined the film conductivities which were found to agree with those measured using the direct current potential drop (DCPD) method

  4. Validation of a Residual Stress Measurement Method by Swept High-Frequency Eddy Currents

    Science.gov (United States)

    Lee, C.; Shen, Y.; Lo, C. C. H.; Nakagawa, N.

    2007-03-01

    This paper reports on a swept high-frequency eddy current (SHFEC) measurement method developed for electromagnetic nondestructive characterization of residual stresses in shot peened aerospace materials. In this approach, we regard shot-peened surfaces as modified surface layers of varying conductivity, and determine the conductivity deviation profile by inversion of the SHFEC data. The SHFEC measurement system consists of a pair of closely matched printed-circuit-board coils driven by laboratory instrument under software control. This provides improved sensitivity and high frequency performance compared to conventional coils, so that swept frequency EC measurements up to 50 MHz can be made to achieve the smallest skin depth of 80 μm for nickel-based superalloys. We devised a conductivity profile inversion procedure based on the laterally uniform multi-layer theory of Cheng, Dodd and Deeds. The main contribution of this paper is the methodology validation. Namely, the forward and inverse models were validated against measurements on artificial layer specimens consisting of metal films with different conductivities placed on a metallic substrate. The inversion determined the film conductivities which were found to agree with those measured using the direct current potential drop (DCPD) method.

  5. Real-time speckle variance swept-source optical coherence tomography using a graphics processing unit.

    Science.gov (United States)

    Lee, Kenneth K C; Mariampillai, Adrian; Yu, Joe X Z; Cadotte, David W; Wilson, Brian C; Standish, Beau A; Yang, Victor X D

    2012-07-01

    Advances in swept source laser technology continues to increase the imaging speed of swept-source optical coherence tomography (SS-OCT) systems. These fast imaging speeds are ideal for microvascular detection schemes, such as speckle variance (SV), where interframe motion can cause severe imaging artifacts and loss of vascular contrast. However, full utilization of the laser scan speed has been hindered by the computationally intensive signal processing required by SS-OCT and SV calculations. Using a commercial graphics processing unit that has been optimized for parallel data processing, we report a complete high-speed SS-OCT platform capable of real-time data acquisition, processing, display, and saving at 108,000 lines per second. Subpixel image registration of structural images was performed in real-time prior to SV calculations in order to reduce decorrelation from stationary structures induced by the bulk tissue motion. The viability of the system was successfully demonstrated in a high bulk tissue motion scenario of human fingernail root imaging where SV images (512 × 512 pixels, n = 4) were displayed at 54 frames per second.

  6. Scaled nonuniform Fourier transform for image reconstruction in swept source optical coherence tomography

    Science.gov (United States)

    Mezgebo, Biniyam; Nagib, Karim; Fernando, Namal; Kordi, Behzad; Sherif, Sherif

    2018-02-01

    Swept Source optical coherence tomography (SS-OCT) is an important imaging modality for both medical and industrial diagnostic applications. A cross-sectional SS-OCT image is obtained by applying an inverse discrete Fourier transform (DFT) to axial interferograms measured in the frequency domain (k-space). This inverse DFT is typically implemented as a fast Fourier transform (FFT) that requires the data samples to be equidistant in k-space. As the frequency of light produced by a typical wavelength-swept laser is nonlinear in time, the recorded interferogram samples will not be uniformly spaced in k-space. Many image reconstruction methods have been proposed to overcome this problem. Most such methods rely on oversampling the measured interferogram then use either hardware, e.g., Mach-Zhender interferometer as a frequency clock module, or software, e.g., interpolation in k-space, to obtain equally spaced samples that are suitable for the FFT. To overcome the problem of nonuniform sampling in k-space without any need for interferogram oversampling, an earlier method demonstrated the use of the nonuniform discrete Fourier transform (NDFT) for image reconstruction in SS-OCT. In this paper, we present a more accurate method for SS-OCT image reconstruction from nonuniform samples in k-space using a scaled nonuniform Fourier transform. The result is demonstrated using SS-OCT images of Axolotl salamander eggs.

  7. Picosecond pulses from wavelength-swept continuous-wave Fourier domain mode-locked lasers.

    Science.gov (United States)

    Eigenwillig, Christoph M; Wieser, Wolfgang; Todor, Sebastian; Biedermann, Benjamin R; Klein, Thomas; Jirauschek, Christian; Huber, Robert

    2013-01-01

    Ultrafast lasers have a crucial function in many fields of science; however, up to now, high-energy pulses directly from compact, efficient and low-power semiconductor lasers are not available. Therefore, we introduce a new approach based on temporal compression of the continuous-wave, wavelength-swept output of Fourier domain mode-locked lasers, where a narrowband optical filter is tuned synchronously to the round-trip time of light in a kilometre-long laser cavity. So far, these rapidly swept lasers enabled orders-of-magnitude speed increase in optical coherence tomography. Here we report on the generation of ~60-70 ps pulses at 390 kHz repetition rate. As energy is stored optically in the long-fibre delay line and not as population inversion in the laser-gain medium, high-energy pulses can now be generated directly from a low-power, compact semiconductor-based oscillator. Our theory predicts subpicosecond pulses with this new technique in the future.

  8. Observations of Traveling Crossflow Resonant Triad Interactions on a Swept Wing

    Science.gov (United States)

    Eppink, Jenna L.; Wlezien, Richard

    2012-01-01

    Experimental evidence indicates the presence of a triad resonance interaction between traveling crossflow modes in a swept wing flow. Results indicate that this interaction occurs when the stationary and traveling crossflow modes have similar and relatively low amplitudes (approx.1% to 6% of the total freestream velocity). The resonant interaction occurs at instability amplitudes well below those typically known to cause transition, yet transition is observed to occur just downstream of the resonance. In each case, two primary linearly unstable traveling crossflow modes are nonlinearly coupled to a higher frequency linearly stable mode at the sum of their frequencies. The higher-frequency mode is linearly stable and presumed to exist as a consequence of the interaction of the two primary modes. Autoand cross-bicoherence are used to determine the extent of phase-matching between the modes, and wavenumber matching confirms the triad resonant nature of the interaction. The bicoherence results indicate a spectral broadening mechanism and the potential path to early transition. The implications for laminar flow control in swept wing flows are significant. Even if stationary crossflow modes remain subcritical, traveling crossflow interactions can lead to early transition.

  9. Ice Roughness and Thickness Evolution on a Swept NACA 0012 Airfoil

    Science.gov (United States)

    McClain, Stephen T.; Vargas, Mario; Tsao, Jen-Ching

    2017-01-01

    Several recent studies have been performed in the Icing Research Tunnel (IRT) at NASA Glenn Research Center focusing on the evolution, spatial variations, and proper scaling of ice roughness on airfoils without sweep exposed to icing conditions employed in classical roughness studies. For this study, experiments were performed in the IRT to investigate the ice roughness and thickness evolution on a 91.44-cm (36-in.) chord NACA 0012 airfoil, swept at 30-deg with 0deg angle of attack, and exposed to both Appendix C and Appendix O (SLD) icing conditions. The ice accretion event times used in the study were less than the time required to form substantially three-dimensional structures, such as scallops, on the airfoil surface. Following each ice accretion event, the iced airfoils were scanned using a ROMER Absolute Arm laser-scanning system. The resulting point clouds were then analyzed using the self-organizing map approach of McClain and Kreeger to determine the spatial roughness variations along the surfaces of the iced airfoils. The resulting measurements demonstrate linearly increasing roughness and thickness parameters with ice accretion time. Further, when compared to dimensionless or scaled results from unswept airfoil investigations, the results of this investigation indicate that the mechanisms for early stage roughness and thickness formation on swept wings are similar to those for unswept wings.

  10. Generation of Fullspan Leading-Edge 3D Ice Shapes for Swept-Wing Aerodynamic Testing

    Science.gov (United States)

    Camello, Stephanie C.; Lee, Sam; Lum, Christopher; Bragg, Michael B.

    2016-01-01

    The deleterious effect of ice accretion on aircraft is often assessed through dry-air flight and wind tunnel testing with artificial ice shapes. This paper describes a method to create fullspan swept-wing artificial ice shapes from partial span ice segments acquired in the NASA Glenn Icing Reserch Tunnel for aerodynamic wind-tunnel testing. Full-scale ice accretion segments were laser scanned from the Inboard, Midspan, and Outboard wing station models of the 65% scale Common Research Model (CRM65) aircraft configuration. These were interpolated and extrapolated using a weighted averaging method to generate fullspan ice shapes from the root to the tip of the CRM65 wing. The results showed that this interpolation method was able to preserve many of the highly three dimensional features typically found on swept-wing ice accretions. The interpolated fullspan ice shapes were then scaled to fit the leading edge of a 8.9% scale version of the CRM65 wing for aerodynamic wind-tunnel testing. Reduced fidelity versions of the fullspan ice shapes were also created where most of the local three-dimensional features were removed. The fullspan artificial ice shapes and the reduced fidelity versions were manufactured using stereolithography.

  11. A Survey of Factors Affecting Blunt Leading-Edge Separation for Swept and Semi-Slender Wings

    Science.gov (United States)

    Luckring, James M.

    2010-01-01

    A survey is presented of factors affecting blunt leading-edge separation for swept and semi-slender wings. This class of separation often results in the onset and progression of separation-induced vortical flow over a slender or semi-slender wing. The term semi-slender is used to distinguish wings with moderate sweeps and aspect ratios from the more traditional highly-swept, low-aspect-ratio slender wing. Emphasis is divided between a selection of results obtained through literature survey a section of results from some recent research projects primarily being coordinated through NATO s Research and Technology Organization (RTO). An aircraft context to these studies is included.

  12. Coordination in vertical jumping

    NARCIS (Netherlands)

    Bobbert, Maarten F.; van Ingen Schenau, Gerrit Jan

    1988-01-01

    The present study was designed to investigate for vertical jumping the relationships between muscle actions, movement pattern and jumping achievement. Ten skilled jumpers performed jumps with preparatory countermovement. Ground reaction forces and cinematographic data were recorded. In addition,

  13. Hybrid vertical cavity laser

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2010-01-01

    A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide.......A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide....

  14. VISUALIZATION FROM INTRAOPERATIVE SWEPT-SOURCE MICROSCOPE-INTEGRATED OPTICAL COHERENCE TOMOGRAPHY IN VITRECTOMY FOR COMPLICATIONS OF PROLIFERATIVE DIABETIC RETINOPATHY.

    Science.gov (United States)

    Gabr, Hesham; Chen, Xi; Zevallos-Carrasco, Oscar M; Viehland, Christian; Dandrige, Alexandria; Sarin, Neeru; Mahmoud, Tamer H; Vajzovic, Lejla; Izatt, Joseph A; Toth, Cynthia A

    2018-01-10

    To evaluate the use of live volumetric (4D) intraoperative swept-source microscope-integrated optical coherence tomography in vitrectomy for proliferative diabetic retinopathy complications. In this prospective study, we analyzed a subgroup of patients with proliferative diabetic retinopathy complications who required vitrectomy and who were imaged by the research swept-source microscope-integrated optical coherence tomography system. In near real time, images were displayed in stereo heads-up display facilitating intraoperative surgeon feedback. Postoperative review included scoring image quality, identifying different diabetic retinopathy-associated pathologies and reviewing the intraoperatively documented surgeon feedback. Twenty eyes were included. Indications for vitrectomy were tractional retinal detachment (16 eyes), combined tractional-rhegmatogenous retinal detachment (2 eyes), and vitreous hemorrhage (2 eyes). Useful, good-quality 2D (B-scans) and 4D images were obtained in 16/20 eyes (80%). In these eyes, multiple diabetic retinopathy complications could be imaged. Swept-source microscope-integrated optical coherence tomography provided surgical guidance, e.g., in identifying dissection planes under fibrovascular membranes, and in determining residual membranes and traction that would benefit from additional peeling. In 4/20 eyes (20%), acceptable images were captured, but they were not useful due to high tractional retinal detachment elevation which was challenging for imaging. Swept-source microscope-integrated optical coherence tomography can provide important guidance during surgery for proliferative diabetic retinopathy complications through intraoperative identification of different complications and facilitation of intraoperative decision making.

  15. Frequency-swept laser light source at 1050 nm with higher bandwidth due to multiple semiconductor optical amplifiers in series

    DEFF Research Database (Denmark)

    Marschall, Sebastian; Thrane, Lars; Andersen, Peter E.

    2009-01-01

    We report on the development of an all-fiber frequency-swept laser light source in the 1050 nm range based on semiconductor optical amplifiers (SOA) with improved bandwidth due to multiple gain media. It is demonstrated that even two SOAs with nearly equal gain spectra can improve the performance...

  16. Vertical and horizontal subsidiarity

    Directory of Open Access Journals (Sweden)

    Ivan V. Daniluk

    2016-02-01

    Full Text Available This article makes an attempt to analyze the principle of subsidiarity in its two main manifestations, namely vertical and horizontal, to outline the principles of relations between the state and regions within the vertical subsidiarity, and features a collaboration of the government and civil society within the horizontal subsidiarity. Scientists identify two types, or two levels of the subsidiarity principle: vertical subsidiarity and horizontal subsidiarity. First, vertical subsidiarity (or territorial concerning relations between the state and other levels of subnational government, such as regions and local authorities; second, horizontal subsidiarity (or functional concerns the relationship between state and citizen (and civil society. Vertical subsidiarity expressed in the context of the distribution of administrative responsibilities to the appropriate higher level lower levels relative to the state structure, ie giving more powers to local government. However, state intervention has subsidiary-lower action against local authorities in cases of insolvency last cope on their own, ie higher organisms intervene only if the duties are less authority is insufficient to achieve the goals. Horizontal subsidiarity is within the relationship between power and freedom, and is based on the assumption that the concern for the common good and the needs of common interest community, able to solve community members (as individuals and citizens’ associations and role of government, in accordance horizontal subsidiarity comes to attracting features subsidiarity assistance, programming, coordination and possibly control.

  17. Repeatability, interocular correlation and agreement of quantitative swept-source optical coherence tomography angiography macular metrics in healthy subjects.

    Science.gov (United States)

    Fang, Danqi; Tang, Fang Yao; Huang, Haifan; Cheung, Carol Y; Chen, Haoyu

    2018-05-29

    To investigate the repeatability, interocular correlation and agreement of quantitative swept-source optical coherence tomography angiography (SS-OCTA) metrics in healthy subjects. Thirty-three healthy normal subjects were enrolled. The macula was scanned four times by an SS-OCTA system using the 3 mm×3 mm mode. The superficial capillary map images were analysed using a MATLAB program. A series of parameters were measured: foveal avascular zone (FAZ) area, FAZ perimeter, FAZ circularity, parafoveal vessel density, fractal dimension and vessel diameter index (VDI). The repeatability of four scans was determined by intraclass correlation coefficient (ICC). Then the averaged results were analysed for intereye difference, correlation and agreement using paired t-test, Pearson's correlation coefficient (r), ICC and Bland-Altman plot. The repeatability assessment of the macular metrics exported high ICC values (ranged from 0.853 to 0.996). There is no statistically significant difference in the OCTA metrics between the two eyes. FAZ area (ICC=0.961, r=0.929) and FAZ perimeter (ICC=0.884, r=0.802) showed excellent binocular correlation. Fractal dimension (ICC=0.732, r=0.578) and VDI (ICC=0.707, r=0.547) showed moderate binocular correlation, while parafoveal vessel density had poor binocular correlation. Bland-Altman plots showed the range of agreement was from -0.0763 to 0.0954 mm 2 for FAZ area and from -0.0491 to 0.1136 for parafoveal vessel density. The macular metrics obtained using SS-OCTA showed excellent repeatability in healthy subjects. We showed high intereye correlation in FAZ area and perimeter, moderate correlation in fractal dimension and VDI, while vessel density had poor correlation in normal healthy subjects. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  18. Dual-Source Swept-Source Optical Coherence Tomography Reconstructed on Integrated Spectrum

    Directory of Open Access Journals (Sweden)

    Shoude Chang

    2012-01-01

    Full Text Available Dual-source swept-source optical coherence tomography (DS-SSOCT has two individual sources with different central wavelengths, linewidth, and bandwidths. Because of the difference between the two sources, the individually reconstructed tomograms from each source have different aspect ratio, which makes the comparison and integration difficult. We report a method to merge two sets of DS-SSOCT raw data in a common spectrum, on which both data have the same spectrum density and a correct separation. The reconstructed tomographic image can seamlessly integrate the two bands of OCT data together. The final image has higher axial resolution and richer spectroscopic information than any of the individually reconstructed tomography image.

  19. Discrete-Roughness-Element-Enhanced Swept-Wing Natural Laminar Flow at High Reynolds Numbers

    Science.gov (United States)

    Malik, Mujeeb; Liao, Wei; Li, Fei; Choudhari, Meelan

    2015-01-01

    Nonlinear parabolized stability equations and secondary-instability analyses are used to provide a computational assessment of the potential use of the discrete-roughness-element technology for extending swept-wing natural laminar flow at chord Reynolds numbers relevant to transport aircraft. Computations performed for the boundary layer on a natural-laminar-flow airfoil with a leading-edge sweep angle of 34.6 deg, freestream Mach number of 0.75, and chord Reynolds numbers of 17 × 10(exp 6), 24 × 10(exp 6), and 30 × 10(exp 6) suggest that discrete roughness elements could delay laminar-turbulent transition by about 20% when transition is caused by stationary crossflow disturbances. Computations show that the introduction of small-wavelength stationary crossflow disturbances (i.e., discrete roughness element) also suppresses the growth of most amplified traveling crossflow disturbances.

  20. Defect inspection of actuator lenses using swept-source optical coherence tomography

    Science.gov (United States)

    Lee, Jaeyul; Shirazi, Muhammad Faizan; Park, Kibeom; Jeon, Mansik; Kim, Jeehyun

    2017-12-01

    Actuator lens industries have gained an enormous interest with the enhancement of various latest communication devices, such as mobile phone and notebooks. The quality of the aforementioned devices can be degraded due to the internal defects of actuator lenses. Therefore, in this study, we implemented swept-source optical coherence tomography (SS-OCT) system to inspect defects of actuator lenses. Owing to the high-resolution of the SS-OCT system, defected foreign substances between the actuator lenses, defective regions of lenses and surface stains were more clearly distinguished through three-dimensional (3D) and two-dimensional (2D) cross-sectional OCT images. Therefore, the implemented SS-OCT system can be considered as a potential application to defect inspection of actuator lens.

  1. Swept-frequency feedback interferometry using terahertz frequency QCLs: a method for imaging and materials analysis.

    Science.gov (United States)

    Rakić, Aleksandar D; Taimre, Thomas; Bertling, Karl; Lim, Yah Leng; Dean, Paul; Indjin, Dragan; Ikonić, Zoran; Harrison, Paul; Valavanis, Alexander; Khanna, Suraj P; Lachab, Mohammad; Wilson, Stephen J; Linfield, Edmund H; Davies, A Giles

    2013-09-23

    The terahertz (THz) frequency quantum cascade laser (QCL) is a compact source of high-power radiation with a narrow intrinsic linewidth. As such, THz QCLs are extremely promising sources for applications including high-resolution spectroscopy, heterodyne detection, and coherent imaging. We exploit the remarkable phase-stability of THz QCLs to create a coherent swept-frequency delayed self-homodyning method for both imaging and materials analysis, using laser feedback interferometry. Using our scheme we obtain amplitude-like and phase-like images with minimal signal processing. We determine the physical relationship between the operating parameters of the laser under feedback and the complex refractive index of the target and demonstrate that this coherent detection method enables extraction of complex refractive indices with high accuracy. This establishes an ultimately compact and easy-to-implement THz imaging and materials analysis system, in which the local oscillator, mixer, and detector are all combined into a single laser.

  2. DRE-Enhanced Swept-Wing Natural Laminar Flow at High Reynolds Numbers

    Science.gov (United States)

    Malik, Mujeeb; Liao, Wei; Li, Fe; Choudhari, Meelan

    2013-01-01

    Nonlinear parabolized stability equations and secondary instability analyses are used to provide a computational assessment of the potential use of the discrete roughness elements (DRE) technology for extending swept-wing natural laminar flow at chord Reynolds numbers relevant to transport aircraft. Computations performed for the boundary layer on a natural laminar flow airfoil with a leading-edge sweep angle of 34.6deg, free-stream Mach number of 0.75 and chord Reynolds numbers of 17 x 10(exp 6), 24 x 10(exp 6) and 30 x 10(exp 6) suggest that DRE could delay laminar-turbulent transition by about 20% when transition is caused by stationary crossflow disturbances. Computations show that the introduction of small wavelength stationary crossflow disturbances (i.e., DRE) also suppresses the growth of most amplified traveling crossflow disturbances.

  3. Spin tunnelling dynamics for spin-1 Bose-Einstein condensates in a swept magnetic field

    International Nuclear Information System (INIS)

    Wang Guanfang; Fu Libin; Liu Jie

    2008-01-01

    We investigate the spin tunnelling of spin-1 Bose-Einstein condensates in a linearly swept magnetic field with a mean-field treatment. We focus on the two typical alkali Bose atoms 87 Rb and 23 Na condensates and study their tunnelling dynamics according to the sweep rates of the external magnetic fields. In the adiabatic (i.e. slowly sweeping) and sudden (i.e. fast sweeping) limits, no tunnelling is observed. For the case of moderate sweep rates, the tunnelling dynamics is found to be very sensitive to the sweep rates, so the plots of tunnelling probability versus sweep rate only become resolvable at a resolution of 10 -4 G s -1 . Moreover, a conserved quantity standing for the magnetization in experiments is found to affect dramatically the dynamics of the spin tunnelling. Theoretically we have given a complete interpretation of the above findings, and our studies could stimulate the experimental study of spinor Bose-Einstein condensates

  4. Swept source optical coherence tomography of objects with arbitrary reflectivity profiles

    Science.gov (United States)

    Mezgebo, Biniyam; Nagib, Karim; Fernando, Namal; Kordi, Behzad; Sherif, Sherif

    2018-03-01

    Swept Source optical coherence tomography (SS-OCT) has become a well established imaging modality for both medical and industrial diagnostic applications. A cross-sectional SS-OCT image is obtained by applying an inverse discrete Fourier transform (DFT) to axial interferogram measured in the frequency domain (k-space). Fourier inversion of the obtained interferogram typically produces a potentially overlapping conjugate mirror image, whose overlap could be avoided by restricting the object to have its highest reflectivity at its surface. However, this restriction may not be fulfilled when imaging a very thin object that is placed on a highly reflective surface, or imaging an object containing a contrast agent with high reflectivity. In this paper, we show that oversampling of the SS-OCT signal in k-space would overcome the need for such restriction on the object. Our result is demonstrated using SS-OCT images of Axolotl salamander eggs.

  5. Swept frequency acoustic interferometry technique for chemical weapons verification and monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, D.N.; Anthony, B.W.; Lizon, D.C.

    1995-03-01

    Nondestructive evaluation (NDE) techniques are important for rapid on-site verification and monitoring of chemical munitions, such as artillery shells and bulk containers. Present NDE techniques provide only limited characterizations of such munitions. This paper describes the development of a novel noninvasive technique, swept-frequency acoustic interferometry (SFAI), that significantly enhances the capability of munitions characterizations. The SFAI technique allows very accurate and simultaneous determination of sound velocity and attenuation of chemical agents over a large frequency range inside artillery shells, in addition to determining agent density. The frequency-dependent sound velocity and attenuation can, in principle, provide molecular relaxation properties of the chemical agent. The same instrument also enables a direct fill-level measurement in bulk containers. Industrial and other applications of this general-purpose technique are also discussed.

  6. Observation of solar radio bursts using swept-frequency radiospectrograph in 20 - 40 MHz band

    International Nuclear Information System (INIS)

    Aoyama, Takashi; Oya, Hiroshi.

    1987-01-01

    A new station for the observation of solar decametric radio bursts has been developed at Miyagi Vocational Training College in Tsukidate, Miyagi, Japan. Using the swept frequency radiospectrograph covering a frequency range from 20 MHz to 40 MHz within 200 msec, with bandwidth of 30 kHz, the radio outbursts from the sun have been currently monitored with colored dynamic spectrum display. After July 1982, successful observations provide the data which include all types of solar radio bursts such as type I, II, III, IV and V in the decametric wavelength range. In addition to these typical radio bursts, rising tone bursts with fast drift rate followed by strong type III bursts and a series of bursts repeating rising and falling tone bursts with slow drift rate have been observed. (author)

  7. FFT swept filtering: a bias-free method for processing fringe signals in absolute gravimeters

    Science.gov (United States)

    Křen, Petr; Pálinkáš, Vojtech; Mašika, Pavel; Val'ko, Miloš

    2018-05-01

    Absolute gravimeters, based on laser interferometry, are widely used for many applications in geoscience and metrology. Although currently the most accurate FG5 and FG5X gravimeters declare standard uncertainties at the level of 2-3 μGal, their inherent systematic errors affect the gravity reference determined by international key comparisons based predominately on the use of FG5-type instruments. The measurement results for FG5-215 and FG5X-251 clearly showed that the measured g-values depend on the size of the fringe signal and that this effect might be approximated by a linear regression with a slope of up to 0.030 μGal/mV . However, these empirical results do not enable one to identify the source of the effect or to determine a reasonable reference fringe level for correcting g-values in an absolute sense. Therefore, both gravimeters were equipped with new measuring systems (according to Křen et al. in Metrologia 53:27-40, 2016. https://doi.org/10.1088/0026-1394/53/1/27 applied for FG5), running in parallel with the original systems. The new systems use an analogue-to-digital converter HS5 to digitize the fringe signal and a new method of fringe signal analysis based on FFT swept bandpass filtering. We demonstrate that the source of the fringe size effect is connected to a distortion of the fringe signal due to the electronic components used in the FG5(X) gravimeters. To obtain a bias-free g-value, the FFT swept method should be applied for the determination of zero-crossings. A comparison of g-values obtained from the new and the original systems clearly shows that the original system might be biased by approximately 3-5 μGal due to improperly distorted fringe signal processing.

  8. On the Effect of Rigid Swept Surface Waves on Turbulent Drag

    Science.gov (United States)

    Denison, M.; Wilkinson, S. P.; Balakumar, P.

    2015-01-01

    Passive turbulent drag reduction techniques are of interest as a cost effective means to improve air vehicle fuel consumption. In the past, rigid surface waves slanted at an angle from the streamwise direction were deemed ineffective to reduce skin friction drag due to the pressure drag that they generate. A recent analysis seeking similarities to the spanwise shear stress generated by spatial Stokes layers suggested that there may be a range of wavelength, amplitude, and orientation in which the wavy surface would reduce turbulent drag. The present work explores, by experiments and Direct Numerical Simulations (DNS), the effect of swept wavy surfaces on skin friction and pressure drag. Plates with shallow and deep wave patterns were rapid-prototyped and tested using a drag balance in the 7x11 inch Low-Speed Wind Tunnel at the NASA LaRC Research Center. The measured drag o set between the wavy plates and the reference at plate is found to be within the experimental repeatability limit. Oil vapor flow measurements indicate a mean spanwise flow over the deep waves. The turbulent flow in channels with at walls, swept wavy walls and spatial Stokes spanwise velocity forcing was simulated at a friction Reynolds number of two hundred. The time-averaged and dynamic turbulent flow characteristics of the three channel types are compared. The drag obtained for the channel with shallow waves is slightly larger than for the at channel, within the range of the experiments. In the case of the large waves, the simulation over predicts the drag. The shortcomings of the Stokes layer analogy model for the estimation of the spanwise shear stress and drag are discussed.

  9. On the ideal and real energy conversion in a straight bladed vertical axis wind turbine. The actuator cylinder flow model compared with experiment

    Energy Technology Data Exchange (ETDEWEB)

    Aaagard Madsen, H.

    1983-01-01

    The ideal and the real energy conversion in a straight bladed vertical axis wind turbine (VAWT) with variable pitch has been studied on basis of the actuator cylinder flow model and experimental data from free wind tests on a 9 m/sup 2/ turbine. Particularly, the theoretical upper power limit of VAWT's has been focused upon in the light of the already existing theories for horizontal axis wind turbines (HAWT's). A remarkable result, differing from prior theories, has turned out through the computations with the actuator cylinder flow model and that is: The maximum ideal power coefficient for VAWT's seams neither to be bounded by the Lanchester-Betz power coefficient limit of 16/27 (actuator disc concept), nor by Glauert's ideal power coefficient curve (taking into account the tip speed ratio), both limits derived with particular reference to HAWT's. Concerning the agreement between analysis and the measurements of the power coefficient, the rotor drag coefficient and the flow velocity vector adjacent to the swept area, it was in general found to be good. However, there seems still to be need for future research on the influence of turbulence in the free wind and dynamic stall on the real energy conversion in VAWT's.

  10. [Duane vertical surgical treatment].

    Science.gov (United States)

    Merino, M L; Gómez de Liaño, P; Merino, P; Franco, G

    2014-04-01

    We report 3 cases with a vertical incomitance in upgaze, narrowing of palpebral fissure, and pseudo-overaction of both inferior oblique muscles. Surgery consisted of an elevation of both lateral rectus muscles with an asymmetrical weakening. A satisfactory result was achieved in 2 cases, whereas a Lambda syndrome appeared in the other case. The surgical technique of upper-insertion with a recession of both lateral rectus muscles improved vertical incomitance in 2 of the 3 patients; however, a residual deviation remains in the majority of cases. Copyright © 2011 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

  11. Vertical market participation

    DEFF Research Database (Denmark)

    Schrader, Alexander; Martin, Stephen

    1998-01-01

    Firms that operate at both levels of vertically related Cournot oligopolies will purchase some input supplies from independent rivals, even though they can produce the good at a lower cost, driving up input price for nonintegrated firms at the final good level. Foreclosure, which avoids this stra......Firms that operate at both levels of vertically related Cournot oligopolies will purchase some input supplies from independent rivals, even though they can produce the good at a lower cost, driving up input price for nonintegrated firms at the final good level. Foreclosure, which avoids...

  12. Vertical Protocol Composition

    DEFF Research Database (Denmark)

    Groß, Thomas; Mödersheim, Sebastian Alexander

    2011-01-01

    The security of key exchange and secure channel protocols, such as TLS, has been studied intensively. However, only few works have considered what happens when the established keys are actually used—to run some protocol securely over the established “channel”. We call this a vertical protocol.......e., that the combination cannot introduce attacks that the individual protocols in isolation do not have. In this work, we prove a composability result in the symbolic model that allows for arbitrary vertical composition (including self-composition). It holds for protocols from any suite of channel and application...

  13. Vertical Search Engines

    OpenAIRE

    Curran, Kevin; Mc Glinchey, Jude

    2017-01-01

    This paper outlines the growth in popularity of vertical search engines, their origins, the differences between them and well-known broad based search engines such as Google and Yahoo. We also discuss their use in business-to-business, their marketing and advertising costs, what the revenue streams are and who uses them.

  14. Vertical cavity laser

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention provides a vertical cavity laser comprising a grating layer comprising an in-plane grating, the grating layer having a first side and having a second side opposite the first side and comprising a contiguous core grating region having a grating structure, wherein an index...

  15. Global Vertical Reference Frame

    Czech Academy of Sciences Publication Activity Database

    Burša, Milan; Kenyon, S.; Kouba, J.; Šíma, Zdislav; Vatrt, V.; Vojtíšková, M.

    -, č. 5 (2009), s. 53-63 ISSN 1801-8483 R&D Projects: GA ČR GA205/08/0328 Institutional research plan: CEZ:AV0Z10030501 Keywords : sea surface topography * satellite altimetry * vertical frames Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  16. Evaluation of circumferential angle closure using iridotrabecular contact index after laser iridotomy by swept-source optical coherence tomography.

    Science.gov (United States)

    Cho, Hyun-Kyung; Ahn, Dongsub; Kee, Changwon

    2017-05-01

    To investigate the quantitative changes of circumferential angle closure after laser iridotomy (LI) using the iridotrabecular contact (ITC) index by Swept-Source optical coherence tomography (OCT). In this prospective observational study conducted in a hospital setting, 42 eyes of 36 patients (five males, 31 females) who underwent LI were included. The mean age was 65.00 ± 8.13 years old and the diagnosis included primary angle closure (PAC, 21 eyes), PAC suspect (16 eyes) and PAC glaucoma (five eyes). Optical coherence tomography (OCT) images were obtained pre-LI and at 1 week post-LI. In each image frame, the scleral spur (SS) and the ITC end-point were marked, from which the ITC index was calculated as a percentage of the angle closure across 360°. Measurements inspected before and after LI included: central anterior chamber depth (ACD), anterior chamber volume (ACV), lens vault (LV), nasal and temporal angle opening distance (AOD), angle recess area (ARA), trabecular-iris space area (TISA), trabecular-iris angle (TIA) at 500 μm and 750 μm from the SS and intraocular pressure (IOP). The ITC index and IOP decreased significantly after LI from 71.52 ± 26.29 to 35.31 ± 27.19 and from 20.64 ± 12.72 mmHg to 14.02 ± 3.49 mmHg, respectively (p  0.05), but ACV increased significantly after LI (p angle parameters except for nasal TIAs increased significantly after LI (all p angle showed a significant decrease after LI, but part of the angle closure was not relieved after LI. Other mechanisms besides pupillary block may play a role together in causing angle closure. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  17. Vertically transmitted rhabdoviruses are found across three insect families and have dynamic interactions with their hosts.

    Science.gov (United States)

    Longdon, Ben; Day, Jonathan P; Schulz, Nora; Leftwich, Philip T; de Jong, Maaike A; Breuker, Casper J; Gibbs, Melanie; Obbard, Darren J; Wilfert, Lena; Smith, Sophia C L; McGonigle, John E; Houslay, Thomas M; Wright, Lucy I; Livraghi, Luca; Evans, Luke C; Friend, Lucy A; Chapman, Tracey; Vontas, John; Kambouraki, Natasa; Jiggins, Francis M

    2017-01-25

    A small number of free-living viruses have been found to be obligately vertically transmitted, but it remains uncertain how widespread vertically transmitted viruses are and how quickly they can spread through host populations. Recent metagenomic studies have found several insects to be infected with sigma viruses (Rhabdoviridae). Here, we report that sigma viruses that infect Mediterranean fruit flies (Ceratitis capitata), Drosophila immigrans, and speckled wood butterflies (Pararge aegeria) are all vertically transmitted. We find patterns of vertical transmission that are consistent with those seen in Drosophila sigma viruses, with high rates of maternal transmission, and lower rates of paternal transmission. This mode of transmission allows them to spread rapidly in populations, and using viral sequence data we found the viruses in D. immigrans and C. capitata had both recently swept through host populations. The viruses were common in nature, with mean prevalences of 12% in C. capitata, 38% in D. immigrans and 74% in P. aegeria We conclude that vertically transmitted rhabdoviruses may be widespread in a broad range of insect taxa, and that these viruses can have dynamic interactions with their hosts. © 2017 The Authors.

  18. Vertically transmitted rhabdoviruses are found across three insect families and have dynamic interactions with their hosts

    Science.gov (United States)

    Day, Jonathan P.; Schulz, Nora; Leftwich, Philip T.; de Jong, Maaike A.; Wilfert, Lena; Smith, Sophia C. L.; McGonigle, John E.; Houslay, Thomas M.; Livraghi, Luca; Evans, Luke C.; Friend, Lucy A.; Vontas, John; Kambouraki, Natasa

    2017-01-01

    A small number of free-living viruses have been found to be obligately vertically transmitted, but it remains uncertain how widespread vertically transmitted viruses are and how quickly they can spread through host populations. Recent metagenomic studies have found several insects to be infected with sigma viruses (Rhabdoviridae). Here, we report that sigma viruses that infect Mediterranean fruit flies (Ceratitis capitata), Drosophila immigrans, and speckled wood butterflies (Pararge aegeria) are all vertically transmitted. We find patterns of vertical transmission that are consistent with those seen in Drosophila sigma viruses, with high rates of maternal transmission, and lower rates of paternal transmission. This mode of transmission allows them to spread rapidly in populations, and using viral sequence data we found the viruses in D. immigrans and C. capitata had both recently swept through host populations. The viruses were common in nature, with mean prevalences of 12% in C. capitata, 38% in D. immigrans and 74% in P. aegeria. We conclude that vertically transmitted rhabdoviruses may be widespread in a broad range of insect taxa, and that these viruses can have dynamic interactions with their hosts. PMID:28100819

  19. Vertical steam generator

    International Nuclear Information System (INIS)

    Cuda, F.; Kondr, M.; Kresta, M.; Kusak, V.; Manek, O.; Turon, S.

    1982-01-01

    A vertical steam generator for nuclear power plants and dual purpose power plants consists of a cylindrical vessel in which are placed heating tubes in the form upside-down U. The heating tubes lead to the jacket of the cylindrical collector placed in the lower part of the steam generator perpendicularly to its vertical axis. The cylindrical collector is divided by a longitudinal partition into the inlet and outlet primary water sections of the heating tubes. One ends of the heating tube leads to the jacket of the collector for primary water feeding and the second ends of the heating tubes into the jacket of the collector which feeds and offtakes primary water from the heating tubes. (B.S.)

  20. Vertical organic transistors.

    Science.gov (United States)

    Lüssem, Björn; Günther, Alrun; Fischer, Axel; Kasemann, Daniel; Leo, Karl

    2015-11-11

    Organic switching devices such as field effect transistors (OFETs) are a key element of future flexible electronic devices. So far, however, a commercial breakthrough has not been achieved because these devices usually lack in switching speed (e.g. for logic applications) and current density (e.g. for display pixel driving). The limited performance is caused by a combination of comparatively low charge carrier mobilities and the large channel length caused by the need for low-cost structuring. Vertical Organic Transistors are a novel technology that has the potential to overcome these limitations of OFETs. Vertical Organic Transistors allow to scale the channel length of organic transistors into the 100 nm regime without cost intensive structuring techniques. Several different approaches have been proposed in literature, which show high output currents, low operation voltages, and comparatively high speed even without sub-μm structuring technologies. In this review, these different approaches are compared and recent progress is highlighted.

  1. Icing Simulation Research Supporting the Ice-Accretion Testing of Large-Scale Swept-Wing Models

    Science.gov (United States)

    Yadlin, Yoram; Monnig, Jaime T.; Malone, Adam M.; Paul, Bernard P.

    2018-01-01

    The work summarized in this report is a continuation of NASA's Large-Scale, Swept-Wing Test Articles Fabrication; Research and Test Support for NASA IRT contract (NNC10BA05 -NNC14TA36T) performed by Boeing under the NASA Research and Technology for Aerospace Propulsion Systems (RTAPS) contract. In the study conducted under RTAPS, a series of icing tests in the Icing Research Tunnel (IRT) have been conducted to characterize ice formations on large-scale swept wings representative of modern commercial transport airplanes. The outcome of that campaign was a large database of ice-accretion geometries that can be used for subsequent aerodynamic evaluation in other experimental facilities and for validation of ice-accretion prediction codes.

  2. A Fiber Bragg Grating Sensor Interrogation System Based on a Linearly Wavelength-Swept Thermo-Optic Laser Chip

    Science.gov (United States)

    Lee, Hyung-Seok; Lee, Hwi Don; Kim, Hyo Jin; Cho, Jae Du; Jeong, Myung Yung; Kim, Chang-Seok

    2014-01-01

    A linearized wavelength-swept thermo-optic laser chip was applied to demonstrate a fiber Bragg grating (FBG) sensor interrogation system. A broad tuning range of 11.8 nm was periodically obtained from the laser chip for a sweep rate of 16 Hz. To measure the linear time response of the reflection signal from the FBG sensor, a programmed driving signal was directly applied to the wavelength-swept laser chip. The linear wavelength response of the applied strain was clearly extracted with an R-squared value of 0.99994. To test the feasibility of the system for dynamic measurements, the dynamic strain was successfully interrogated with a repetition rate of 0.2 Hz by using this FBG sensor interrogation system. PMID:25177803

  3. Comparison of central corneal thickness with four noncontact devices: An agreement analysis of swept-source technology

    OpenAIRE

    Erhan Ozyol; Pelin Özyol

    2017-01-01

    Purpose: The purpose of this study was to compare the central corneal thickness (CCT) measurements of four noncontact devices in healthy eyes. Materials and Methods: In a sample of 45 healthy controls, CCT was measured using an optical biometer (IOLMaster 700) based on swept-source optical coherence tomography (SS-OCT), high-resolution rotating Scheimpflug camera system (Pentacam HR), spectral-domain OCT (SD-OCT) device with an anterior segment module (Spectralis), and noncontact pachymetry (...

  4. Phase-sensitive optical coherence tomography-based vibrometry using a highly phase-stable akinetic swept laser source

    Energy Technology Data Exchange (ETDEWEB)

    Applegate, Brian E.; Park, Jesung; Carbajal, Esteban [Department of Biomedical Engineering, Texas A& M University, College Station, Texas (United States); Oghalai, John S. [Department of Otolaryngology - Head and Neck Surgery, Stanford University, Stanford, California (United States)

    2015-12-31

    Phase-sensitive Optical Coherence Tomography (PhOCT) is an emerging tool for in vivo investigation of the vibratory function of the intact middle and inner ear. PhOCT is able to resolve micron scale tissue morphology in three dimensions as well as measure picometer scale motion at each spatial position. Most PhOCT systems to date have relied upon the phase stability offered by spectrometer detection. On the other hand swept laser source based PhOCT offers a number of advantages including balanced detection, long imaging depths, and high imaging speeds. Unfortunately the inherent phase instability of traditional swept laser sources has necessitated complex user developed hardware/software solutions to restore phase sensitivity. Here we present recent results using a prototype swept laser that overcomes these issues. The akinetic swept laser is electronically tuned and precisely controls sweeps without any mechanical movement, which results in high phase stability. We have developed an optical fiber based PhOCT system around the akinetic laser source that had a 1550 nm center wavelength and a sweep rate of 140 kHz. The stability of the system was measured to be 4.4 pm with a calibrated reflector, thus demonstrating near shot noise limited performance. Using this PhOCT system, we have acquired structural and vibratory measurements of the middle ear in a mouse model, post mortem. The quality of the results suggest that the akinetic laser source is a superior laser source for PhOCT with many advantages that greatly reduces the required complexity of the imaging system.

  5. Performance, Stability, and Control Investigation at Mach Numbers from 0.60 to 1.05 of a Model of the "Swallow" with Outer Wing Panels Swept 75 degree with and without Power Simulations

    Science.gov (United States)

    Schmeer, James W.; Cassetti, Marlowe D.

    1960-01-01

    An investigation of the performance, stability, and control characteristics of a variable-sweep arrow-wing model with the outer wing panels swept 75 deg. has been conducted in the Langley 16-foot transonic tunnel. Four outboard engines located above and below the wing provided propulsive thrust, and, by deflecting in the pitch direction and rotating in the lateral plane, also produced control forces. The engine nacelles incorporated swept lateral and vertical fins for aerodynamic stability and control. Jet-off data were obtained with flow-through nacelles, simulating inlet flow; jet thrust and hot-jet interference effects were obtained with faired-nose nacelles housing hydrogen peroxide gas generators. Six-component force and moment data were obtained at Mach numbers from 0.60 to 1.05 through a range of angles of attack and angles of side-slip. Control characteristics were obtained by deflecting the nacelle-fin combinations as elevators, rudders, and ailerons at several fixed angles for each control. The results indicate that the basic wing-body configuration becomes neutrally stable or unstable at a lift coefficient of 0.15; addition of nacelles with fins delayed instability to a lift coefficient of 0.30. Addition of nacelles to the wing-body configuration increased minimum drag from 0.0058 to 0.0100 at a Mach number of 0.60 and from 0.0080 to 0.0190 at a Mach number of 1.05 with corresponding reductions in maximum lift-drag ratio of 12 percent and 33 percent, respectively. The nacelle-fin combinations were ineffective as longitudinal controls but were adequate as directional and lateral controls. The model with nacelles and fins was directionally and laterally stable; the stability generally increased with increasing lift. Jet interference effects on stability and control characteristics were small but the adverse effects on drag were greater than would be expected for isolated nacelles.

  6. Assessment of circumferential angle-closure by the iris-trabecular contact index with swept-source optical coherence tomography.

    Science.gov (United States)

    Baskaran, Mani; Ho, Sue-Wei; Tun, Tin A; How, Alicia C; Perera, Shamira A; Friedman, David S; Aung, Tin

    2013-11-01

    To evaluate the diagnostic performance of the iris-trabecular contact (ITC) index, a measure of the degree of angle-closure, using swept-source optical coherence tomography (SSOCT, CASIA SS-1000, Tomey Corporation, Nagoya, Japan) in comparison with gonioscopy. Prospective observational study. A total of 108 normal subjects and 32 subjects with angle-closure. The SSOCT 3-dimensional angle scans, which obtain radial scans for the entire circumference of the angle, were performed under dark conditions and analyzed using customized software by a single examiner masked to the subjects' clinical details. The ITC index was calculated as a percentage of the angle that was closed on SSOCT images. First-order agreement coefficient (AC1) statistics and area under the receiver operating characteristic curve (AUC) analyses were performed for angle-closure on the basis of the ITC index in comparison with gonioscopy. Angle-closure on gonioscopy was defined as nonvisibility of posterior trabecular meshwork for at least 2 quadrants. Agreement of the ITC index with gonioscopically defined angle-closure was assessed using the AC1 statistic. Study subjects were predominantly Chinese (95.7%) and female (70.7%), with a mean age of 59.2 (standard deviation, 8.9) years. The median ITC index was 15.24% for gonioscopically open-angle eyes (n = 108) and 48.5% for closed-angle eyes (n = 32) (P = 0.0001). The agreement for angle-closure based on ITC index cutoffs (>35% and ≥50%) and gonioscopic angle-closure was 0.699 and 0.718, respectively. The AUC for angle-closure detection using the ITC index was 0.83 (95% confidence interval, 0.76-0.89), with an ITC index >35% having a sensitivity of 71.9% and specificity of 84.3%. The ITC index is a summary measure of the circumferential extent of angle-closure as imaged with SSOCT. The index had moderate agreement and good diagnostic performance for angle-closure with gonioscopy as the reference standard. Copyright © 2013 American Academy of

  7. Corneal thickness and elevation measurements using swept-source optical coherence tomography and slit scanning topography in normal and keratoconic eyes.

    Science.gov (United States)

    Jhanji, Vishal; Yang, Bingzhi; Yu, Marco; Ye, Cong; Leung, Christopher K S

    2013-11-01

    To compare corneal thickness and corneal elevation using swept source optical coherence tomography and slit scanning topography. Prospective study. 41 normal and 46 keratoconus subjects. All eyes were imaged using swept source optical coherence tomography and slit scanning tomography during the same visit. Mean corneal thickness and best-fit sphere measurements were compared between the instruments. Agreement of measurements between swept source optical coherence tomography and scanning slit topography was analyzed. Intra-rater reproducibility coefficient and intraclass correlation coefficient were evaluated. In normal eyes, central corneal thickness measured by swept source optical coherence tomography was thinner compared with slit scanning topography (p topography. In keratoconus eyes, central corneal thickness was thinner on swept source optical coherence tomography than slit scanning topography (p = 0.081) and ultrasound pachymetry (p = 0.001). There were significant differences between thinnest corneal thickness, and, anterior and posterior best-fit sphere measurements between both instruments (p topography. With better reproducibility coefficients and intraclass correlation coefficients, swept source optical coherence tomography may provide a reliable alternative for measurement of corneal parameters. © 2013 The Authors. Clinical and Experimental Ophthalmology © 2013 Royal Australian and New Zealand College of Ophthalmologists.

  8. Accelerating solutions of one-dimensional unsteady PDEs with GPU-based swept time-space decomposition

    Science.gov (United States)

    Magee, Daniel J.; Niemeyer, Kyle E.

    2018-03-01

    The expedient design of precision components in aerospace and other high-tech industries requires simulations of physical phenomena often described by partial differential equations (PDEs) without exact solutions. Modern design problems require simulations with a level of resolution difficult to achieve in reasonable amounts of time-even in effectively parallelized solvers. Though the scale of the problem relative to available computing power is the greatest impediment to accelerating these applications, significant performance gains can be achieved through careful attention to the details of memory communication and access. The swept time-space decomposition rule reduces communication between sub-domains by exhausting the domain of influence before communicating boundary values. Here we present a GPU implementation of the swept rule, which modifies the algorithm for improved performance on this processing architecture by prioritizing use of private (shared) memory, avoiding interblock communication, and overwriting unnecessary values. It shows significant improvement in the execution time of finite-difference solvers for one-dimensional unsteady PDEs, producing speedups of 2 - 9 × for a range of problem sizes, respectively, compared with simple GPU versions and 7 - 300 × compared with parallel CPU versions. However, for a more sophisticated one-dimensional system of equations discretized with a second-order finite-volume scheme, the swept rule performs 1.2 - 1.9 × worse than a standard implementation for all problem sizes.

  9. Statistics of the first passage time of Brownian motion conditioned by maximum value or area

    International Nuclear Information System (INIS)

    Kearney, Michael J; Majumdar, Satya N

    2014-01-01

    We derive the moments of the first passage time for Brownian motion conditioned by either the maximum value or the area swept out by the motion. These quantities are the natural counterparts to the moments of the maximum value and area of Brownian excursions of fixed duration, which we also derive for completeness within the same mathematical framework. Various applications are indicated. (paper)

  10. Control of stationary crossflow modes in swept Hiemenz flows with dielectric barrier discharge plasma actuators

    Science.gov (United States)

    Wang, Zhefu; Wang, Liang; Fu, Song

    2017-09-01

    Sensitivity analyses and non-linear parabolized stability equations are solved to provide a computational assessment of the potential use of a Dielectric Barrier Discharge (DBD) plasma actuator for a prolonging laminar region in swept Hiemenz flow. The derivative of the kinetic energy with respect to the body force is deduced, and its components in different directions are defined as sensitivity functions. The results of sensitivity analyses and non-linear parabolized stability equations both indicate that the introduction of a body force as the plasma actuator at the bottom of a crossflow vortex can mitigate instability to delay flow transition. In addition, the actuator is more effective when placed more upstream until the neutral point. In fact, if the actuator is sufficiently close to the neutral point, it is likely to act as a strong disturbance over-riding the natural disturbance and dominating transition. Different operating voltages of the DBD actuators are tested, resulting in an optimal practice for transition delay. The results demonstrate that plasma actuators offer great potential for transition control.

  11. Swept frequency measurements of microwave antennas in feline and canine brain

    International Nuclear Information System (INIS)

    Salcman, M.; Neuberth, G.; Nudelman, R.W.; Ferraro, F.T.; Hartman, M.

    1986-01-01

    Interstitial microwave hyperthermia may prove to be an important therapy for malignant brain tumors. For safety and efficiency, the size and number of intracranial microwave antennas needs to be limited. Low power swept frequency measurements of VSWR were carried out in the brains of anesthetized cats and dogs utilizing stereotactically placed monopole antennas. The coupling efficiency of antennas at any frequency was degraded (VSWR>2:1) if a length of antenna less than 2h was inserted or if a plastic catheter was utilized. Such measurements indicate that (h) can be shortened 25% from the resonant length without seriously degrading antenna performance. The total length can be halved if a catheter with a high dielectric is used. High power tests (2-10w) of short antennas at 915 MHz in a ceramic catheter (e = 10) at 45-50 0 C produce thermal fields approximately 2 cm in diameter in normal brain. It should be possible to efficiently and safely heat human brain tumors of average size utilizing these antennas and catheters at 915 MHz

  12. Applicability of a panel method, which includes nonlinear effects, to a forward-swept-wing aircraft

    Science.gov (United States)

    Ross, J. C.

    1984-01-01

    The ability of a lower order panel method VSAERO, to accurately predict the lift and pitching moment of a complete forward-swept-wing/canard configuration was investigated. The program can simulate nonlinear effects including boundary-layer displacement thickness, wake roll up, and to a limited extent, separated wakes. The predictions were compared with experimental data obtained using a small-scale model in the 7- by 10- Foot Wind Tunnel at NASA Ames Research Center. For the particular configuration under investigation, wake roll up had only a small effect on the force and moment predictions. The effect of the displacement thickness modeling was to reduce the lift curve slope slightly, thus bringing the predicted lift into good agreement with the measured value. Pitching moment predictions were also improved by the boundary-layer simulation. The separation modeling was found to be sensitive to user inputs, but appears to give a reasonable representation of a separated wake. In general, the nonlinear capabilities of the code were found to improve the agreement with experimental data. The usefullness of the code would be enhanced by improving the reliability of the separated wake modeling and by the addition of a leading edge separation model.

  13. All fiber optics circular-state swept source polarization-sensitive optical coherence tomography.

    Science.gov (United States)

    Lin, Hermann; Kao, Meng-Chun; Lai, Chih-Ming; Huang, Jyun-Cin; Kuo, Wen-Chuan

    2014-02-01

    A swept source (SS)-based circular-state (CS) polarization-sensitive optical coherence tomography (PS-OCT) constructed entirely with polarization-maintaining fiber optics components is proposed with the experimental verification. By means of the proposed calibration scheme, bulk quarter-wave plates can be replaced by fiber optics polarization controllers to, therefore, realize an all-fiber optics CS SSPS-OCT. We also present a numerical dispersion compensation method, which can not only enhance the axial resolution, but also improve the signal-to-noise ratio of the images. We demonstrate that this compact and portable CS SSPS-OCT system with an accuracy comparable to bulk optics systems requires less stringent lens alignment and can possibly serve as a technology to realize PS-OCT instrument for clinical applications (e.g., endoscopy). The largest deviations in the phase retardation (PR) and fast-axis (FA) angle due to sample probe in the linear scanning and a rotation angle smaller than 65 deg were of the same order as those in stationary probe setups. The influence of fiber bending on the measured PR and FA is also investigated. The largest deviations of the PR were 3.5 deg and the measured FA change by ~12 to 21 deg. Finally, in vivo imaging of the human fingertip and nail was successfully demonstrated with a linear scanning probe.

  14. Dynamic Sensor Interrogation Using Wavelength-Swept Laser with a Polygon-Scanner-Based Wavelength Filter

    Science.gov (United States)

    Kwon, Yong Seok; Ko, Myeong Ock; Jung, Mi Sun; Park, Ik Gon; Kim, Namje; Han, Sang-Pil; Ryu, Han-Cheol; Park, Kyung Hyun; Jeon, Min Yong

    2013-01-01

    We report a high-speed (∼2 kHz) dynamic multiplexed fiber Bragg grating (FBG) sensor interrogation using a wavelength-swept laser (WSL) with a polygon-scanner-based wavelength filter. The scanning frequency of the WSL is 18 kHz, and the 10 dB scanning bandwidth is more than 90 nm around a center wavelength of 1,540 nm. The output from the WSL is coupled into the multiplexed FBG array, which consists of five FBGs. The reflected Bragg wavelengths of the FBGs are 1,532.02 nm, 1,537.84 nm, 1,543.48 nm, 1,547.98 nm, and 1,553.06 nm, respectively. A dynamic periodic strain ranging from 500 Hz to 2 kHz is applied to one of the multiplexed FBGs, which is fixed on the stage of the piezoelectric transducer stack. Good dynamic performance of the FBGs and recording of their fast Fourier transform spectra have been successfully achieved with a measuring speed of 18 kHz. The signal-to-noise ratio and the bandwidth over the whole frequency span are determined to be more than 30 dB and around 10 Hz, respectively. We successfully obtained a real-time measurement of the abrupt change of the periodic strain. The dynamic FBG sensor interrogation system can be read out with a WSL for high-speed and high-sensitivity real-time measurement. PMID:23899934

  15. Optic axis determination by fibre-based polarization-sensitive swept-source optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Lu Zenghai; Kasaragod, Deepa K; Matcher, Stephen J, E-mail: z.lu@sheffield.ac.uk, E-mail: s.j.matcher@sheffield.ac.uk [Department of Materials Science and Engineering, Kroto Research Institute, University of Sheffield, North Campus, Broad Lane, Sheffield, S3 7HQ (United Kingdom)

    2011-02-21

    We describe a fibre-based variable-incidence angle (VIA) polarization-sensitive swept-source optical coherence tomography (PS-SS-OCT) system to determine the 3D optical axis of birefringent biological tissues. Single-plane VIA-PS-OCT is also explored which requires measurement of the absolute fast-axis orientation. A state-of-the-art PS-SS-OCT system with some improvements both in hardware and software was used to determine the apparent optical birefringence of equine tendon for a number of different illumination directions. Polar and azimuthal angles of cut equine tendon were produced by the VIA method and compared with the nominal values. A quarter waveplate (QWP) and equine tendon were used as test targets to validate the fast-axis measurements using the system. Polar and azimuthal angles of cut equine tendon broadly agreed with the expected values within about 8% of the nominal values. A theoretical and experimental analysis of the effect of the sample arm fibre on determination of optical axis orientation using a proposed definition based on the orientation of the eigenpolarization ellipse experimentally confirms that this algorithm only works correctly for special settings of the sample arm fibre. A proposed algorithm based on the angle between Stokes vectors on the Poincare sphere is confirmed to work for all settings of the sample arm fibre. A calibration procedure is proposed to remove the sign ambiguity of the measured orientation and was confirmed experimentally by using the QWP.

  16. Optic axis determination by fibre-based polarization-sensitive swept-source optical coherence tomography

    International Nuclear Information System (INIS)

    Lu Zenghai; Kasaragod, Deepa K; Matcher, Stephen J

    2011-01-01

    We describe a fibre-based variable-incidence angle (VIA) polarization-sensitive swept-source optical coherence tomography (PS-SS-OCT) system to determine the 3D optical axis of birefringent biological tissues. Single-plane VIA-PS-OCT is also explored which requires measurement of the absolute fast-axis orientation. A state-of-the-art PS-SS-OCT system with some improvements both in hardware and software was used to determine the apparent optical birefringence of equine tendon for a number of different illumination directions. Polar and azimuthal angles of cut equine tendon were produced by the VIA method and compared with the nominal values. A quarter waveplate (QWP) and equine tendon were used as test targets to validate the fast-axis measurements using the system. Polar and azimuthal angles of cut equine tendon broadly agreed with the expected values within about 8% of the nominal values. A theoretical and experimental analysis of the effect of the sample arm fibre on determination of optical axis orientation using a proposed definition based on the orientation of the eigenpolarization ellipse experimentally confirms that this algorithm only works correctly for special settings of the sample arm fibre. A proposed algorithm based on the angle between Stokes vectors on the Poincare sphere is confirmed to work for all settings of the sample arm fibre. A calibration procedure is proposed to remove the sign ambiguity of the measured orientation and was confirmed experimentally by using the QWP.

  17. Vortex lift augmentation by suction on a 60 deg swept Gothic wing

    Science.gov (United States)

    Taylor, A. H.; Jackson, L. R.; Huffman, J. K.

    1982-01-01

    An experimental investigation was conducted in the Langley high-speed 7- by 10-foot wind tunnel to determine the aerodynamic performance of suction applied near the wing tips above the trailing edge of a 60 deg swept Gothic wing. Moveable suction inlets were symmetrically mounted in the proximity of the trailing edge, and the amount of suction was varied to maximize wing lift. Tests were conducted at Mach 0.15, 0.30, and 0.45, and the angle of attack was varied from -4 to 50 deg. The suction augmentation increases the lift coefficient over the entire range of angle of attack. The lift improvement exceeds the unaugmented wing lift by over 20%. Moreover, the augmented lift exceeds the lift predicted by vortex lattice theory to 30 deg angle of attack. Suction augmentation is postulated to strengthen the vortex system by increasing its velocity and making it more concentrated. This causes the vortex breakdown to be delayed to a higher angle of attack

  18. Density, temperature, and potential fluctuation measurements by the swept Langmuir probe technique in Wendelstein 7-AS

    International Nuclear Information System (INIS)

    Giannone, L.; Balbin, R.; Niedermeyer, H.; Endler, M.; Herre, G.; Hidalgo, C.; Rudyj, A.; Theimer, G.; Verplanke, P.

    1994-01-01

    In the Wendelstein 7-AS stellarator (W7-AS) [Plasma Phys. Controlled Fusion 33, 1591 (1991)], current-voltage characteristics of the Langmuir probe at sweep frequencies in the range 400 kHz to 1 MHz were measured and it was found that the mean and fluctuation values of the ion saturation current, floating potential, and electron temperature were independent of the sweep frequency. A radial scan in the vicinity of the velocity shear layer was performed. The simultaneous sweeping of 3 probe tips showed a statistically significant spatial coherence of the fluctuations in the poloidal direction and a decrease in spatial coherence of the fluctuations with increasing tip separation could be demonstrated. The observation of a change in the propagation direction of fluctuations as the shear layer was crossed and a calculation of the transport spectrum show that the swept probe method is capable of reproducing known results. Apparent temperature fluctuations, due to variations of density and potential during a sweep, are shown by simulations to be only of importance at frequencies above half the Nyquist frequency

  19. Crossflow-Vortex Breakdown on Swept Wings: Correlation of Nonlinear Physics

    Science.gov (United States)

    Joslin, R. D.; Streett, C. L.

    1994-01-01

    The spatial evolution of cross flow-vortex packets in a laminar boundary layer on a swept wing are computed by the direct numerical simulation of the incompressible Navier- Stokes equations. A wall-normal velocity distribution of steady suction and blowing at the wing surface is used to generate a strip of equally spaced and periodic disturbances along the span. Three simulations are conducted to study the effect of initial amplitude on the disturbance evolution, to determine the role of traveling cross ow modes in transition, and to devise a correlation function to guide theories of transition prediction. In each simulation, the vortex packets first enter a chordwise region of linear independent growth, then, the individual packets coalesce downstream and interact with adjacent packets, and, finally, the vortex packets nonlinearly interact to generate inflectional velocity profiles. As the initial amplitude of the disturbance is increased, the length of the evolution to breakdown decreases. For this pressure gradient, stationary modes dominate the disturbance evolution. A two-coeffcient function was devised to correlate the simulation results. The coefficients, combined with a single simulation result, provide sufficient information to generate the evolution pattern for disturbances of any initial amplitude.

  20. Longitudinal study of arteriogenesis with swept source optical coherence tomography and hyperspectral imaging

    Science.gov (United States)

    Poole, Kristin M.; Patil, Chetan A.; Nelson, Christopher E.; McCormack, Devin R.; Madonna, Megan C.; Duvall, Craig L.; Skala, Melissa C.

    2014-03-01

    Peripheral arterial disease (PAD) is an atherosclerotic disease of the extremities that leads to high rates of myocardial infarction and stroke, increased mortality, and reduced quality of life. PAD is especially prevalent in diabetic patients, and is commonly modeled by hind limb ischemia in mice to study collateral vessel development and test novel therapies. Current techniques used to assess recovery cannot obtain quantitative, physiological data non-invasively. Here, we have applied hyperspectral imaging and swept source optical coherence tomography (OCT) to study longitudinal changes in blood oxygenation and vascular morphology, respectively, intravitally in the diabetic mouse hind limb ischemia model. Additionally, recommended ranges for controlling physiological variability in blood oxygenation with respect to respiration rate and body core temperature were determined from a control animal experiment. In the longitudinal study with diabetic mice, hyperspectral imaging data revealed the dynamics of blood oxygenation recovery distally in the ischemic footpad. In diabetic mice, there is an early increase in oxygenation that is not sustained in the long term. Quantitative analysis of vascular morphology obtained from Hessian-filtered speckle variance OCT volumes revealed temporal dynamics in vascular density, total vessel length, and vessel diameter distribution in the adductor muscle of the ischemic limb. The combination of hyperspectral imaging and speckle variance OCT enabled acquisition of novel functional and morphological endpoints from individual animals, and provides a more robust platform for future preclinical evaluations of novel therapies for PAD.

  1. Analysis of Low Speed Stall Aerodynamics of a Swept Wing with Laminar Flow Glove

    Science.gov (United States)

    Bui, Trong T.

    2014-01-01

    Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) analysis was conducted to study the low-speed stall aerodynamics of a GIII aircraft's swept wing modified with a laminar-flow wing glove. The stall aerodynamics of the gloved wing were analyzed and compared with the unmodified wing for the flight speed of 120 knots and altitude of 2300 ft above mean sea level (MSL). The Star-CCM+ polyhedral unstructured CFD code was first validated for wing stall predictions using the wing-body geometry from the First American Institute of Aeronautics and Astronautics (AIAA) CFD High-Lift Prediction Workshop. It was found that the Star-CCM+ CFD code can produce results that are within the scattering of other CFD codes considered at the workshop. In particular, the Star-CCM+ CFD code was able to predict wing stall for the AIAA wing-body geometry to within 1 degree of angle of attack as compared to benchmark wind-tunnel test data. Current results show that the addition of the laminar-flow wing glove causes the gloved wing to stall much earlier than the unmodified wing. Furthermore, the gloved wing has a different stall characteristic than the clean wing, with no sharp lift drop-off at stall for the gloved wing.

  2. Analysis of Low-Speed Stall Aerodynamics of a Swept Wing with Laminar-Flow Glove

    Science.gov (United States)

    Bui, Trong T.

    2014-01-01

    Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) analysis was conducted to study the low-speed stall aerodynamics of a GIII aircraft's swept wing modified with a laminar-flow wing glove. The stall aerodynamics of the gloved wing were analyzed and compared with the unmodified wing for the flight speed of 120 knots and altitude of 2300 ft above mean sea level (MSL). The Star-CCM+ polyhedral unstructured CFD code was first validated for wing stall predictions using the wing-body geometry from the First American Institute of Aeronautics and Astronautics (AIAA) CFD High-Lift Prediction Workshop. It was found that the Star-CCM+ CFD code can produce results that are within the scattering of other CFD codes considered at the workshop. In particular, the Star-CCM+ CFD code was able to predict wing stall for the AIAA wing-body geometry to within 1 degree of angle of attack as compared to benchmark wind-tunnel test data. Current results show that the addition of the laminar-flow wing glove causes the gloved wing to stall much earlier than the unmodified wing. Furthermore, the gloved wing has a different stall characteristic than the clean wing, with no sharp lift drop-off at stall for the gloved wing.

  3. Standoff detection of turbulent chemical mixture plumes using a swept external cavity quantum cascade laser

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Mark C. [Pacific Northwest National Laboratory, Richland, Washington; Brumfield, Brian E. [Pacific Northwest National Laboratory, Richland, Washington

    2017-08-21

    We demonstrate standoff detection of turbulent mixed-chemical plumes using a broadly-tunable external cavity quantum cascade laser (ECQCL). The ECQCL was directed through plumes of mixed methanol/ethanol vapor to a partially-reflective surface located 10 m away. The reflected power was measured as the ECQCL was swept over its tuning range of 930-1065 cm-1 (9.4-10.8 µm) at rates up to 200 Hz. Analysis of the transmission spectra though the plume was performed to determine chemical concentrations with time resolution of 0.005 s. Comparison of multiple spectral sweep rates of 2 Hz, 20 Hz, and 200 Hz shows that higher sweep rates reduce effects of atmospheric and source turbulence, resulting in lower detection noise and more accurate measurement of the rapidly-changing chemical concentrations. Detection sensitivities of 0.13 ppm*m for MeOH and 1.2 ppm*m for EtOH are demonstrated for a 200 Hz spectral sweep rate, normalized to 1 s detection time.

  4. DNS of Laminar-Turbulent Transition in Swept-Wing Boundary Layers

    Science.gov (United States)

    Duan, L.; Choudhari, M.; Li, F.

    2014-01-01

    Direct numerical simulation (DNS) is performed to examine laminar to turbulent transition due to high-frequency secondary instability of stationary crossflow vortices in a subsonic swept-wing boundary layer for a realistic natural-laminar-flow airfoil configuration. The secondary instability is introduced via inflow forcing and the mode selected for forcing corresponds to the most amplified secondary instability mode that, in this case, derives a majority of its growth from energy production mechanisms associated with the wall-normal shear of the stationary basic state. An inlet boundary condition is carefully designed to allow for accurate injection of instability wave modes and minimize acoustic reflections at numerical boundaries. Nonlinear parabolized stability equation (PSE) predictions compare well with the DNS in terms of modal amplitudes and modal shape during the strongly nonlinear phase of the secondary instability mode. During the transition process, the skin friction coefficient rises rather rapidly and the wall-shear distribution shows a sawtooth pattern that is analogous to the previously documented surface flow visualizations of transition due to stationary crossflow instability. Fully turbulent features are observed in the downstream region of the flow.

  5. Effect of Thickness-to-Chord Ratio on Flow Structure of Low Swept Delta Wing

    Science.gov (United States)

    Gulsacan, Burak; Sencan, Gizem; Yavuz, Mehmet Metin

    2017-11-01

    The effect of thickness-to-chord (t/C) ratio on flow structure of a delta wing with sweep angle of 35 degree is characterized in a low speed wind tunnel using laser illuminated smoke visualization, particle image velocimetry, and surface pressure measurements. Four different t/C ratio varying from 4.75% to 19% are tested at angles of attack 4, 6, 8, and 10 degrees for Reynolds numbers Re =10,000 and 35,000. The results indicate that the effect of thickness-to-chord ratio on flow structure is quite substantial, such that, as the wing thickness increases, the flow structure transforms from leading edge vortex to three-dimensional separated flow regime. The wing with low t/C ratio of 4.75% experiences pronounced surface separation at significantly higher angle of attack compared to the wing with high t/C ratio. The results might explain some of the discrepancies reported in previously conducted studies related to delta wings. In addition, it is observed that the thickness of the shear layer separated from windward side of the wing is directly correlated with the thickness of the wing. To conclude, the flow structure on low swept delta wing is highly affected by t/C ratio, which in turn might indicate the potential usage of wing thickness as an effective flow control parameter.

  6. Vertical axis wind turbine

    International Nuclear Information System (INIS)

    Obretenov, V.; Tsalov, T.; Chakarov, T.

    2012-01-01

    In recent years, the interest in wind turbines with vertical axis noticeably increased. They have some important advantages: low cost, relatively simple structure, reliable packaging system of wind aggregate long period during which require no maintenance, low noise, independence of wind direction, etc.. The relatively low efficiency, however, makes them applicable mainly for small facilities. The work presents a methodology and software for approximately aerodynamic design of wind turbines of this type, and also analyzed the possibility of improving the efficiency of their workflow

  7. Vertical vector face lift.

    Science.gov (United States)

    Somoano, Brian; Chan, Joanna; Morganroth, Greg

    2011-01-01

    Facial rejuvenation using local anesthesia has evolved in the past decade as a safer option for patients seeking fewer complications and minimal downtime. Mini- and short-scar face lifts using more conservative incision lengths and extent of undermining can be effective in the younger patient with lower face laxity and minimal loose, elastotic neck skin. By incorporating both an anterior and posterior approach and using an incision length between the mini and more traditional face lift, the Vertical Vector Face Lift can achieve longer-lasting and natural results with lesser cost and risk. Submentoplasty and liposuction of the neck and jawline, fundamental components of the vertical vector face lift, act synergistically with superficial musculoaponeurotic system plication to reestablish a more youthful, sculpted cervicomental angle, even in patients with prominent jowls. Dramatic results can be achieved in the right patient by combining with other procedures such as injectable fillers, chin implants, laser resurfacing, or upper and lower blepharoplasties. © 2011 Wiley Periodicals, Inc.

  8. Vertical organic transistors

    International Nuclear Information System (INIS)

    Lüssem, Björn; Günther, Alrun; Fischer, Axel; Kasemann, Daniel; Leo, Karl

    2015-01-01

    Organic switching devices such as field effect transistors (OFETs) are a key element of future flexible electronic devices. So far, however, a commercial breakthrough has not been achieved because these devices usually lack in switching speed (e.g. for logic applications) and current density (e.g. for display pixel driving). The limited performance is caused by a combination of comparatively low charge carrier mobilities and the large channel length caused by the need for low-cost structuring. Vertical Organic Transistors are a novel technology that has the potential to overcome these limitations of OFETs. Vertical Organic Transistors allow to scale the channel length of organic transistors into the 100 nm regime without cost intensive structuring techniques. Several different approaches have been proposed in literature, which show high output currents, low operation voltages, and comparatively high speed even without sub-μm structuring technologies. In this review, these different approaches are compared and recent progress is highlighted. (topical review)

  9. Defense of fake fingerprint attacks using a swept source laser optical coherence tomography setup

    Science.gov (United States)

    Meissner, Sven; Breithaupt, Ralph; Koch, Edmund

    2013-03-01

    The most established technique for the identification at biometric access control systems is the human fingerprint. While every human fingerprint is unique, fingerprints can be faked very easily by using thin layer fakes. Because commercial fingerprint scanners use only a two-dimensional image acquisition of the finger surface, they can only hardly differentiate between real fingerprints and fingerprint fakes applied on thin layer materials. A Swept Source OCT system with an A-line rate of 20 kHz and a lateral and axial resolution of approximately 13 μm, a centre wavelength of 1320 nm and a band width of 120 nm (FWHM) was used to acquire fingerprints and finger tips with overlying fakes. Three-dimensional volume stacks with dimensions of 4.5 mm x 4 mm x 2 mm were acquired. The layering arrangement of the imaged finger tips and faked finger tips was analyzed and subsequently classified into real and faked fingerprints. Additionally, sweat gland ducts were detected and consulted for the classification. The manual classification between real fingerprints and faked fingerprints results in almost 100 % correctness. The outer as well as the internal fingerprint can be recognized in all real human fingers, whereby this was not possible in the image stacks of the faked fingerprints. Furthermore, in all image stacks of real human fingers the sweat gland ducts were detected. The number of sweat gland ducts differs between the test persons. The typical helix shape of the ducts was observed. In contrast, in images of faked fingerprints we observe abnormal layer arrangements and no sweat gland ducts connecting the papillae of the outer fingerprint and the internal fingerprint. We demonstrated that OCT is a very useful tool to enhance the performance of biometric control systems concerning attacks by thin layer fingerprint fakes.

  10. Three-Dimensional Cataract Crystalline Lens Imaging With Swept-Source Optical Coherence Tomography.

    Science.gov (United States)

    de Castro, Alberto; Benito, Antonio; Manzanera, Silvestre; Mompeán, Juan; Cañizares, Belén; Martínez, David; Marín, Jose María; Grulkowski, Ireneusz; Artal, Pablo

    2018-02-01

    To image, describe, and characterize different features visible in the crystalline lens of older adults with and without cataract when imaged three-dimensionally with a swept-source optical coherence tomography (SS-OCT) system. We used a new SS-OCT laboratory prototype designed to enhance the visualization of the crystalline lens and imaged the entire anterior segment of both eyes in two groups of participants: patients scheduled to undergo cataract surgery, n = 17, age range 36 to 91 years old, and volunteers without visual complains, n = 14, age range 20 to 81 years old. Pre-cataract surgery patients were also clinically graded according to the Lens Opacification Classification System III. The three-dimensional location and shape of the visible opacities were compared with the clinical grading. Hypo- and hyperreflective features were visible in the lens of all pre-cataract surgery patients and in some of the older adults in the volunteer group. When the clinical examination revealed cortical or subcapsular cataracts, hyperreflective features were visible either in the cortex parallel to the surfaces of the lens or in the posterior pole. Other type of opacities that appeared as hyporeflective localized features were identified in the cortex of the lens. The OCT signal in the nucleus of the crystalline lens correlated with the nuclear cataract clinical grade. A dedicated OCT is a useful tool to study in vivo the subtle opacities in the cataractous crystalline lens, revealing its position and size three-dimensionally. The use of these images allows obtaining more detailed information on the age-related changes leading to cataract.

  11. Edge turbulence effect on ultra-fast swept reflectometry core measurements in tokamak plasmas

    Science.gov (United States)

    Zadvitskiy, G. V.; Heuraux, S.; Lechte, C.; Hacquin, S.; Sabot, R.

    2018-02-01

    Ultra-fast frequency-swept reflectometry (UFSR) enables one to provide information about the turbulence radial wave-number spectrum and perturbation amplitude with good spatial and temporal resolutions. However, a data interpretation of USFR is quiet tricky. An iterative algorithm to solve this inverse problem was used in past works, Gerbaud (2006 Rev. Sci. Instrum. 77 10E928). For a direct solution, a fast 1D Helmholtz solver was used. Two-dimensional effects are strong and should be taken into account during data interpretation. As 2D full-wave codes are still too time consuming for systematic application, fast 2D approaches based on the Born approximation are of prime interest. Such methods gives good results in the case of small turbulence levels. However in tokamak plasmas, edge turbulence is usually very strong and can distort and broaden the probing beam Sysoeva et al (2015 Nucl. Fusion 55 033016). It was shown that this can change reflectometer phase response from the plasma core. Comparison between 2D full wave computation and the simplified Born approximation was done. The approximated method can provide a right spectral shape, but it is unable to describe a change of the spectral amplitude with an edge turbulence level. Computation for the O-mode wave with the linear density profile in the slab geometry and for realistic Tore-Supra density profile, based on the experimental data turbulence amplitude and spectrum, were performed to investigate the role of strong edge turbulence. It is shown that the spectral peak in the signal amplitude variation spectrum which rises with edge turbulence can be a signature of strong edge turbulence. Moreover, computations for misaligned receiving and emitting antennas were performed. It was found that the signal amplitude variation peak changes its position with a receiving antenna poloidal displacement.

  12. The Vertical Farm: A Review of Developments and Implications for the Vertical City

    Directory of Open Access Journals (Sweden)

    Kheir Al-Kodmany

    2018-02-01

    Full Text Available This paper discusses the emerging need for vertical farms by examining issues related to food security, urban population growth, farmland shortages, “food miles”, and associated greenhouse gas (GHG emissions. Urban planners and agricultural leaders have argued that cities will need to produce food internally to respond to demand by increasing population and to avoid paralyzing congestion, harmful pollution, and unaffordable food prices. The paper examines urban agriculture as a solution to these problems by merging food production and consumption in one place, with the vertical farm being suitable for urban areas where available land is limited and expensive. Luckily, recent advances in greenhouse technologies such as hydroponics, aeroponics, and aquaponics have provided a promising future to the vertical farm concept. These high-tech systems represent a paradigm shift in farming and food production and offer suitable and efficient methods for city farming by minimizing maintenance and maximizing yield. Upon reviewing these technologies and examining project prototypes, we find that these efforts may plant the seeds for the realization of the vertical farm. The paper, however, closes by speculating about the consequences, advantages, and disadvantages of the vertical farm’s implementation. Economic feasibility, codes, regulations, and a lack of expertise remain major obstacles in the path to implementing the vertical farm.

  13. The Revolutionary Vertical Lift Technology (RVLT) Project

    Science.gov (United States)

    Yamauchi, Gloria K.

    2018-01-01

    The Revolutionary Vertical Lift Technology (RVLT) Project is one of six projects in the Advanced Air Vehicles Program (AAVP) of the NASA Aeronautics Research Mission Directorate. The overarching goal of the RVLT Project is to develop and validate tools, technologies, and concepts to overcome key barriers for vertical lift vehicles. The project vision is to enable the next generation of vertical lift vehicles with aggressive goals for efficiency, noise, and emissions, to expand current capabilities and develop new commercial markets. The RVLT Project invests in technologies that support conventional, non-conventional, and emerging vertical-lift aircraft in the very light to heavy vehicle classes. Research areas include acoustic, aeromechanics, drive systems, engines, icing, hybrid-electric systems, impact dynamics, experimental techniques, computational methods, and conceptual design. The project research is executed at NASA Ames, Glenn, and Langley Research Centers; the research extensively leverages partnerships with the US Army, the Federal Aviation Administration, industry, and academia. The primary facilities used by the project for testing of vertical-lift technologies include the 14- by 22-Ft Wind Tunnel, Icing Research Tunnel, National Full-Scale Aerodynamics Complex, 7- by 10-Ft Wind Tunnel, Rotor Test Cell, Landing and Impact Research facility, Compressor Test Facility, Drive System Test Facilities, Transonic Turbine Blade Cascade Facility, Vertical Motion Simulator, Mobile Acoustic Facility, Exterior Effects Synthesis and Simulation Lab, and the NASA Advanced Supercomputing Complex. To learn more about the RVLT Project, please stop by booth #1004 or visit their website at https://www.nasa.gov/aeroresearch/programs/aavp/rvlt.

  14. Results of Low Power Deicer tests on a swept inlet component in the NASA Lewis Icing Research Tunnel

    Science.gov (United States)

    Bond, Thomas H.; Shin, Jaiwon

    1993-01-01

    Tests were conducted under a USAF/NASA Low Power Deicer program on two expulsive technologies to examine system performance on hardware representative of a modern aircraft part. The BF Goodrich Electro-Expulsive Deicing System and Pneumatic Impulse Ice Protection system were installed on a swept, compound curve, engine inlet component with varying leading edge radius, and tested through a range of icing and system operating conditions in the NASA Lewis Icing Research Tunnel. A description of the experimental procedure and results, including residual ice thickness, shed ice particle size, and changes in system energy/pressure characteristics are presented.

  15. An analysis of the effects of aeroelasticity on static longitudinal stability and control of a swept-back-wing airplane

    Science.gov (United States)

    Skoog, Richard B

    1951-01-01

    A theoretical analysis of the effects of aeroelasticity on the stick-fixed static longitudinal stability and elevator angle required for balance of an airplane is presented together with calculated effects for a swept-wing bomber of relatively high flexibility. Although large changes in stability due to certain parameters are indicated for the example airplane, the over-all stability change after considering all parameters was quite small, compared to the individual effects, due to the counterbalancing of wing and tail contributions. The effect of flexibility on longitudinal control for the example airplane was found to be of little real importance.

  16. Towards Fast Measurement of the Electron Temperature in the SOL of ASDEX Upgrade Using Swept Langmuir Probes

    Czech Academy of Sciences Publication Activity Database

    Müller, H. W.; Adámek, Jiří; Horáček, Jan; Ionita, C.; Mehlmann, F.; Rohde, V.; Schrittwieser, R.

    2010-01-01

    Roč. 50, č. 9 (2010), s. 847-853 ISSN 0863-1042. [International Workshop on Electric Probes in Magnetized Plasmas/8th./. Innsbruck, 21.09.2009-24.09.2009] R&D Projects: GA AV ČR KJB100430901; GA ČR GA202/09/1467 Institutional research plan: CEZ:AV0Z20430508 Keywords : Tokamak * Langmuir probe * swept probe * ball-pen probe * fast temperature measurement * ELM Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.006, year: 2010 http://onlinelibrary.wiley.com/doi/10.1002/ctpp.201010144/pdf

  17. Simulating charge transport to understand the spectral response of Swept Charge Devices

    Science.gov (United States)

    Athiray, P. S.; Sreekumar, P.; Narendranath, S.; Gow, J. P. D.

    2015-11-01

    Context. Swept Charge Devices (SCD) are novel X-ray detectors optimized for improved spectral performance without any demand for active cooling. The Chandrayaan-1 X-ray Spectrometer (C1XS) experiment onboard the Chandrayaan-1 spacecraft used an array of SCDs to map the global surface elemental abundances on the Moon using the X-ray fluorescence (XRF) technique. The successful demonstration of SCDs in C1XS spurred an enhanced version of the spectrometer on Chandrayaan-2 using the next-generation SCD sensors. Aims: The objective of this paper is to demonstrate validation of a physical model developed to simulate X-ray photon interaction and charge transportation in a SCD. The model helps to understand and identify the origin of individual components that collectively contribute to the energy-dependent spectral response of the SCD. Furthermore, the model provides completeness to various calibration tasks, such as generating spectral matrices (RMFs - redistribution matrix files), estimating efficiency, optimizing event selection logic, and maximizing event recovery to improve photon-collection efficiency in SCDs. Methods: Charge generation and transportation in the SCD at different layers related to channel stops, field zones, and field-free zones due to photon interaction were computed using standard drift and diffusion equations. Charge collected in the buried channel due to photon interaction in different volumes of the detector was computed by assuming a Gaussian radial profile of the charge cloud. The collected charge was processed further to simulate both diagonal clocking read-out, which is a novel design exclusive for SCDs, and event selection logic to construct the energy spectrum. Results: We compare simulation results of the SCD CCD54 with measurements obtained during the ground calibration of C1XS and clearly demonstrate that our model reproduces all the major spectral features seen in calibration data. We also describe our understanding of interactions at

  18. The first-passage area for drifted Brownian motion and the moments of the Airy distribution

    International Nuclear Information System (INIS)

    Kearney, Michael J; Majumdar, Satya N; Martin, Richard J

    2007-01-01

    An exact expression for the distribution of the area swept out by a drifted Brownian motion till its first-passage time is derived. A study of the asymptotic behaviour confirms earlier conjectures and clarifies their range of validity. The analysis leads to a simple closed-form solution for the moments of the Airy distribution. (fast track communication)

  19. Trade Liberalisation and Vertical Integration

    DEFF Research Database (Denmark)

    Bache, Peter Arendorf; Laugesen, Anders

    We build a three-country model of international trade in final goods and intermediate inputs and study the relation between different types of trade liberalisation and vertical integration. Firms are heterogeneous with respect to both productivity and factor intensity as observed in data. Final......-good producers face decisions on exporting, vertical integration of intermediate-input production, and whether the intermediate-input production should be offshored to a low-wage country. We find that the fractions of final-good producers that pursue either vertical integration, offshoring, or exporting are all...... increasing when intermediate-input or final-goods trade is liberalised and when the fixed cost of vertical integration is reduced. At the same time, one observes firms that shift away from either vertical integration, offshoring, or exporting. Further, we provide guidance for testing the open...

  20. Progress and Prospects in Developing Marine Vertical Datum

    Directory of Open Access Journals (Sweden)

    ZHOU Xinghua

    2017-10-01

    Full Text Available Marine vertical datum system construction is the basic work of marine surveying. In the 2009-2012, China has preliminarily constructed the transformation and unification of different height/depth datum model in the China Sea of 80 nautical mile. In recent years, this model has been extended to the South China Sea, the western Pacific and the eastern Indian Ocean, and then a seamless vertical datum model in the south and north pole area to the whole world gradually will be constructed in the near future, this is the foundation of supporting the digital ocean construction in China. This paper mainly discusses the research status of marine vertical datum construction which had been carried out in major coastal countries or regions, analyzes the main work and approaches and key technologies in the process of the marine vertical datum system building, and then expounds the achievements and existing problems in the practice of our country marine vertical datum building.

  1. Simultaneous topography and tomography of latent fingerprints using full-field swept-source optical coherence tomography

    Science.gov (United States)

    Dubey, Satish Kumar; Singh Mehta, Dalip; Anand, Arun; Shakher, Chandra

    2008-01-01

    We demonstrate simultaneous topography and tomography of latent fingerprints using full-field swept-source optical coherence tomography (OCT). The swept-source OCT system comprises a superluminescent diode (SLD) as broad-band light source, an acousto-optic tunable filter (AOTF) as frequency tuning device, and a compact, nearly common-path interferometer. Both the amplitude and the phase map of the interference fringe signal are reconstructed. Optical sectioning of the latent fingerprint sample is obtained by selective Fourier filtering and the topography is retrieved from the phase map. Interferometry, selective filtering, low coherence and hence better resolution are some of the advantages of the proposed system over the conventional fingerprint detection techniques. The present technique is non-invasive in nature and does not require any physical or chemical processing. Therefore, the quality of the sample does not alter and hence the same fingerprint can be used for other types of forensic test. Exploitation of low-coherence interferometry for fingerprint detection itself provides an edge over other existing techniques as fingerprints can even be lifted from low-reflecting surfaces. The proposed system is very economical and compact.

  2. Analysis of unswept and swept wing chordwise pressure data from an oscillating NACA 0012 airfoil experiment. Volume 1: Technical Report

    Science.gov (United States)

    St.hilaire, A. O.; Carta, F. O.

    1983-01-01

    The unsteady chordwise force response on the airfoil surface was investigated and its sensitivity to the various system parameters was examined. A further examination of unsteady aerodynamic data on a tunnel spanning wing (both swept and unswept), obtained in a wind tunnel, was performed. The main body of this data analysis was carried out by analyzing the propagation speed of pressure disturbances along the chord and by studying the behavior of the unsteady part of the chordwise pressure distribution at various points of the airfoil pitching cycle. It was found that Mach number effects dominate the approach to and the inception of both static and dynamic stall. The stall angle decreases as the Mach number increases. However, sweep dominates the load behavior within the stall regime. Large phase differences between unswept and swept responses, that do not exist at low lift coefficient, appear once the stall boundary is penetrated. It was also found that reduced frequency is not a reliable indicator of the unsteady aerodynamic response in the high angle of attack regime.

  3. Combined in-depth, 3D, en face imaging of the optic disc, optic disc pits and optic disc pit maculopathy using swept-source megahertz OCT at 1050 nm.

    Science.gov (United States)

    Maertz, Josef; Kolb, Jan Philip; Klein, Thomas; Mohler, Kathrin J; Eibl, Matthias; Wieser, Wolfgang; Huber, Robert; Priglinger, Siegfried; Wolf, Armin

    2018-02-01

    To demonstrate papillary imaging of eyes with optic disc pits (ODP) or optic disc pit associated maculopathy (ODP-M) with ultrahigh-speed swept-source optical coherence tomography (SS-OCT) at 1.68 million A-scans/s. To generate 3D-renderings of the papillary area with 3D volume-reconstructions of the ODP and highly resolved en face images from a single densely-sampled megahertz-OCT (MHz-OCT) dataset for investigation of ODP-characteristics. A 1.68 MHz-prototype SS-MHz-OCT system at 1050 nm based on a Fourier-domain mode-locked laser was employed to acquire high-definition, 3D datasets with a dense sampling of 1600 × 1600 A-scans over a 45° field of view. Six eyes with ODPs, and two further eyes with glaucomatous alteration or without ocular pathology are presented. 3D-rendering of the deep papillary structures, virtual 3D-reconstructions of the ODPs and depth resolved isotropic en face images were generated using semiautomatic segmentation. 3D-rendering and en face imaging of the optic disc, ODPs and ODP associated pathologies showed a broad spectrum regarding ODP characteristics. Between individuals the shape of the ODP and the appending pathologies varied considerably. MHz-OCT en face imaging generates distinct top-view images of ODPs and ODP-M. MHz-OCT generates high resolution images of retinal pathologies associated with ODP-M and allows visualizing ODPs with depths of up to 2.7 mm. Different patterns of ODPs can be visualized in patients for the first time using 3D-reconstructions and co-registered high-definition en face images extracted from a single densely sampled 1050 nm megahertz-OCT (MHz-OCT) dataset. As the immediate vicinity to the SAS and the site of intrapapillary proliferation is located at the bottom of the ODP it is crucial to image the complete structure and the whole depth of ODPs. Especially in very deep pits, where non-swept-source OCT fails to reach the bottom, conventional swept-source devices and the MHz-OCT alike are feasible

  4. New Urban Vertical Axis Wind Turbine Design

    Directory of Open Access Journals (Sweden)

    Alexandru-Mihai CISMILIANU

    2015-12-01

    Full Text Available This paper develops a different approach for enhancing the performance of Vertical Axis Wind Turbines for the use in the urban or rural environment and remote isolated residential areas. Recently the vertical axis wind turbines (VAWT have become more attractive due to the major advantages of this type of turbines in comparison to the horizontal axis wind turbines. We aim to enhance the overall performance of the VAWT by adding a second set of blades (3 x 2=6 blades following the rules of biplane airplanes. The model has been made to operate at a maximum power in the range of the TSR between 2 to 2.5. The performances of the VAWT were investigated numerically and experimentally and justify the new proposed design.

  5. Inservice testing of vertical pumps

    International Nuclear Information System (INIS)

    Cornman, R.E. Jr.; Schumann, K.E.

    1994-01-01

    This paper focuses on the problems that may occur with vertical pumps while inservice tests are conducted in accordance with existing American Society of Mechanical Engineers Code, Section XI, standards. The vertical pump types discussed include single stage, multistage, free surface, and canned mixed flow pumps. Primary emphasis is placed on the hydraulic performance of the pump and the internal and external factors to the pump that impact hydraulic performance. In addition, the paper considers the mechanical design features that can affect the mechanical performance of vertical pumps. The conclusion shows how two recommended changes in the Code standards may increase the quality of the pump's operational readiness assessment during its service life

  6. Mitigating the negative impacts of tall wind turbines on bats: Vertical activity profiles and relationships to wind speed.

    Science.gov (United States)

    Wellig, Sascha D; Nusslé, Sébastien; Miltner, Daniela; Kohle, Oliver; Glaizot, Olivier; Braunisch, Veronika; Obrist, Martin K; Arlettaz, Raphaël

    2018-01-01

    Wind turbines represent a source of hazard for bats, especially through collision with rotor blades. With increasing technical development, tall turbines (rotor-swept zone 50-150 m above ground level) are becoming widespread, yet we lack quantitative information about species active at these heights, which impedes proposing targeted mitigation recommendations for bat-friendly turbine operation. We investigated vertical activity profiles of a bat assemblage, and their relationships to wind speed, within a major valley of the European Alps where tall wind turbines are being deployed. To monitor bat activity we installed automatic recorders at sequentially increasing heights from ground level up to 65 m, with the goal to determine species-specific vertical activity profiles and to link them to wind speed. Bat call sequences were analysed with an automatic algorithm, paying particular attention to mouse-eared bats (Myotis myotis and Myotis blythii) and the European free-tailed bat (Tadarida teniotis), three locally rare species. The most often recorded bats were the Common pipistrelle (Pipistrellus pipistrellus) and Savi's pipistrelle (Hypsugo savii). Mouse-eared bats were rarely recorded, and mostly just above ground, appearing out of risk of collision. T. teniotis had a more evenly distributed vertical activity profile, often being active at rotor level, but its activity at that height ceased above 5 ms-1 wind speed. Overall bat activity in the rotor-swept zone declined with increasing wind speed, dropping below 5% above 5.4 ms-1. Collision risk could be drastically reduced if nocturnal operation of tall wind turbines would be restricted to wind speeds above 5 ms-1. Such measure should be implemented year-round because T. teniotis remains active in winter. This operational restriction is likely to cause only small energy production losses at these tall wind turbines, although further analyses are needed to assess these losses precisely.

  7. Vertical Ridge Augmentation of the Atrophic Posterior Mandible with Sandwich Technique: Bone Block from the Chin Area versus Corticocancellous Bone Block Allograft—Clinical and Histological Prospective Randomized Controlled Study

    Directory of Open Access Journals (Sweden)

    Luigi Laino

    2014-01-01

    Full Text Available The aim of the present study is to compare the histological aspects of bone formation in atrophic posterior mandibles augmented by autologous bone block from chin area with corticocancellous bone block allograft used as inlays with the sandwich technique. Materials and Methods. Sixteen patients with bilateral partial edentulism in the posterior mandible were selected. The residual bone height, preliminarily measured by computed tomography scans, ranged between 5 and 7 mm from the inferior alveolar nerve. All patients required regeneration procedure with autologous bone block from chin area (control group versus bone block allograft Puros (Zimmer Dental, 1900 Aston Avenue, Carlsbad, CA, USA (test group. Histological and histomorphometric samples were collected at the time of implant positioning in order to analyze the percentage of newly formed bone, the residual graft material, and marrow spaces/soft tissue. Results. No statistically significant differences between the two groups were found regarding the percentage of newly formed bone. The percentage of residual grafted material was significantly higher in the test group, whilst the percentage of marrow spaces was higher in control group. Conclusions. In conclusion, both procedures supported good results, although the use of bone blocks allograft was less invasive and preferable than harvesting bone from the mental symphysis.

  8. Vertical axis wind turbine airfoil

    Science.gov (United States)

    Krivcov, Vladimir; Krivospitski, Vladimir; Maksimov, Vasili; Halstead, Richard; Grahov, Jurij Vasiljevich

    2012-12-18

    A vertical axis wind turbine airfoil is described. The wind turbine airfoil can include a leading edge, a trailing edge, an upper curved surface, a lower curved surface, and a centerline running between the upper surface and the lower surface and from the leading edge to the trailing edge. The airfoil can be configured so that the distance between the centerline and the upper surface is the same as the distance between the centerline and the lower surface at all points along the length of the airfoil. A plurality of such airfoils can be included in a vertical axis wind turbine. These airfoils can be vertically disposed and can rotate about a vertical axis.

  9. Trade Liberalisation and Vertical Integration

    DEFF Research Database (Denmark)

    Bache, Peter Arendorf; Laugesen, Anders Rosenstand

    We build a three-country model of international trade in final goods and intermediate inputs and study the relation between four different types of trade liberalisation and vertical integration. Firms are heterogeneous with respect to both productivity and factor (headquarter) intensity. Final......-good producers face decisions on exporting, vertical integration of intermediate-input production, and whether the intermediate-input production should be offshored to a low-wage country. We find that the fractions of final-good producers that pursue either vertical integration, offshoring, or exporting are all...... increasing when intermediate-input trade or final-goods trade is liberalised. Finally, we provide guidance for testing the open-economy property rights theory of the firm using firm-level data and surprisingly show that the relationship between factor (headquarter) intensity and the likelihood of vertical...

  10. The TEXT upgrade vertical interferometer

    International Nuclear Information System (INIS)

    Hallock, G.A.; Gartman, M.L.; Li, W.; Chiang, K.; Shin, S.; Castles, R.L.; Chatterjee, R.; Rahman, A.S.

    1992-01-01

    A far-infrared interferometer has been installed on TEXT upgrade to obtain electron density profiles. The primary system views the plasma vertically through a set of large (60-cm radialx7.62-cm toroidal) diagnostic ports. A 1-cm channel spacing (59 channels total) and fast electronic time response is used, to provide high resolution for radial profiles and perturbation experiments. Initial operation of the vertical system was obtained late in 1991, with six operating channels

  11. Characterization of vertical mixing in oscillatory vegetated flows

    Science.gov (United States)

    Abdolahpour, M.; Ghisalberti, M.; Lavery, P.; McMahon, K.

    2016-02-01

    Seagrass meadows are primary producers that provide important ecosystem services, such as improved water quality, sediment stabilisation and trapping and recycling of nutrients. Most of these ecological services are strongly influenced by the vertical exchange of water across the canopy-water interface. That is, vertical mixing is the main hydrodynamic process governing the large-scale ecological and environmental impact of seagrass meadows. The majority of studies into mixing in vegetated flows have focused on steady flow environments whereas many coastal canopies are subjected to oscillatory flows driven by surface waves. It is known that the rate of mass transfer will vary greatly between unidirectional and oscillatory flows, necessitating a specific investigation of mixing in oscillatory canopy flows. In this study, we conducted an extensive laboratory investigation to characterise the rate of vertical mixing through a vertical turbulent diffusivity (Dt,z). This has been done through gauging the evolution of vertical profiles of concentration (C) of a dye sheet injected into a wave-canopy flow. Instantaneous measurement of the variance of the vertical concentration distribution ( allowed the estimation of a vertical turbulent diffusivity (). Two types of model canopies, rigid and flexible, with identical heights and frontal areas, were subjected to a wide and realistic range of wave height and period. The results showed two important mechanisms that dominate vertical mixing under different conditions: a shear layer that forms at the top of the canopy and wake turbulence generated by the stems. By allowing a coupled contribution of wake and shear layer mixing, we present a relationship that can be used to predict the rate of vertical mixing in coastal canopies. The results further showed that the rate of vertical mixing within flexible vegetation was always lower than the corresponding rigid canopy, confirming the impact of plant flexibility on canopy

  12. Vertical designs and agriculture joined for food production in the modules for urban vertical gardens.

    Directory of Open Access Journals (Sweden)

    Fritz Hammerling Navas Navarro

    2012-10-01

    Full Text Available Modules for Vertical Urban Gardens (MHUG are a hybrid of vertical gardens and urban agriculture. Vertical gardens have been recognized for the past 2500 years, mainly in the form of the Hanging Gardens of Babylon, while urban agriculture is being practiced today by more than 700 million people worldwide. The benefits that MHUV offers are multiple, but perhaps the most significant is the consumption of foods free of chemicals, free of GMO’s, irrigated with potable water, and that are 100% organic. It is presented a “culinary and medicinal module” that can be implemented in the kitchen area, on roofs, terraces, balconies or patios, where species such as thyme, mint, peppermint, parsley, lemon balm and rosemary can be at hand when preparing dishes. The module consists of three plastic baskets that are recyclable and resistant to decay. Each basket has four rows with space for fourteen seedlings. The baskets are first lined on the interior with a black geotextile, and then are covered with a mesh (polisombra which helps support the substrate and seedlings. Each basket rests on a structure made of recycled wood (from pallets or crates that both holds the basket vertically and serves as a rain cover. The cages measure 0.33m by 0.55m by 0.14m. Each module comes with hosing and connectors for a drip irrigation system, and an instructional manual. The modules demonstrate the benefits of urban agriculture combined with the beauty and modality of vertical gardens, leading to useful applications for food production and decoration in the spaces where vertical urban gardens are possible.

  13. Reliability Analysis of Geotechnical Failure Modes for Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, H. F.

    2000-01-01

    Vertical wall breakwaters are usually designed as concrete caissons placed on the top of a rubble mound foundation or a rubble bedding layer. The purpose of the breakwater is usually to protect the area behind the breakwater from being flooded by large waves. The area protected can for example be...

  14. An experimental study of the effects of bodyside compression on forward swept sidewall compression inlets ingesting a turbulent boundary layer

    Science.gov (United States)

    Rodi, Patrick E.

    1993-01-01

    Forward swept sidewall compression inlets have been tested in the Mach 4 Blowdown Facility at the NASA Langley Research Center to study the effects of bodyside compression surfaces on inlet performance in the presence of an incoming turbulent boundary layer. The measurements include mass flow capture and mean surface pressure distributions obtained during simulated combustion pressure increases downstream of the inlet. The kerosene-lampblack surface tracer technique has been used to obtain patterns of the local wall shear stress direction. Inlet performance is evaluated using starting and unstarting characteristics, mass capture, mean surface pressure distributions and permissible back pressure limits. The results indicate that inlet performance can be improved with selected bodyside compression surfaces placed between the inlet sidewalls.

  15. Standard practice for process compensated resonance testing via swept sine input for metallic and Non-Metallic parts

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice describes a general procedure for using the process compensated resonance testing (PCRT) via swept sine input method to identify metallic and non-metallic parts’ resonant pattern differences that can be used to indentify parts with anomalies causing deficiencies in the expected performance of the part in service. This practice is intended for use with instruments capable of exciting, measuring, recording, and analyzing multiple whole body mechanical vibration resonant frequencies within parts exhibiting acoustical ringing in the audio, or ultrasonic, resonant frequency ranges, or both. PCRT is used in the presence of manufacturing process variance to distinguish acceptable parts from those containing significant anomalies in physical characteristics expected to significantly alter the performance. Such physical characteristics include, but are not limited to, cracks, voids, porosity, shrink, inclusions, discontinuities, grain and crystalline structure differences, density related anomalies...

  16. Development of a structural optimization capability for the aeroelastic tailoring of composite rotor blades with straight and swept tips

    Science.gov (United States)

    Friedmann, P. P.; Venkatesan, C.; Yuan, K.

    1992-01-01

    This paper describes the development of a new structural optimization capability aimed at the aeroelastic tailoring of composite rotor blades with straight and swept tips. The primary objective is to reduce vibration levels in forward flight without diminishing the aeroelastic stability margins of the blade. In the course of this research activity a number of complicated tasks have been addressed: (1) development of a new, aeroelastic stability and response analysis; (2) formulation of a new comprehensive sensitive analysis, which facilitates the generation of the appropriate approximations for the objective and the constraints; (3) physical understanding of the new model and, in particular, determination of its potential for aeroelastic tailoring, and (4) combination of the newly developed analysis capability, the sensitivity derivatives and the optimizer into a comprehensive optimization capability. The first three tasks have been completed and the fourth task is in progress.

  17. Increasing signal-to-noise ratio of swept-source optical coherence tomography by oversampling in k-space

    Science.gov (United States)

    Nagib, Karim; Mezgebo, Biniyam; Thakur, Rahul; Fernando, Namal; Kordi, Behzad; Sherif, Sherif

    2018-03-01

    Optical coherence tomography systems suffer from noise that could reduce ability to interpret reconstructed images correctly. We describe a method to increase the signal-to-noise ratio of swept-source optical coherence tomography (SSOCT) using oversampling in k-space. Due to this oversampling, information redundancy would be introduced in the measured interferogram that could be used to reduce white noise in the reconstructed A-scan. We applied our novel scaled nonuniform discrete Fourier transform to oversampled SS-OCT interferograms to reconstruct images of a salamander egg. The peak-signal-to-noise (PSNR) between the reconstructed images using interferograms sampled at 250MS/s andz50MS/s demonstrate that this oversampling increased the signal-to-noise ratio by 25.22 dB.

  18. Vertical-Screw-Auger Conveyer Feeder

    Science.gov (United States)

    Walton, Otis (Inventor); Vollmer, Hubert J. (Inventor)

    2016-01-01

    A conical feeder is attached to a vertically conveying screw auger. The feeder is equipped with scoops and rotated from the surface to force-feed regolith the auger. Additional scoops are possible by adding a cylindrical section above the conical funnel section. Such then allows the unit to collect material from swaths larger in diameter than the enclosing casing pipe of the screw auger. A third element includes a flexible screw auger. All three can be used in combination in microgravity and zero atmosphere environments to drill and recover a wide area of subsurface regolith and entrained volatiles through a single access point on the surface.

  19. ULTRAHIGH SPEED SWEPT SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF RETINAL AND CHORIOCAPILLARIS ALTERATIONS IN DIABETIC PATIENTS WITH AND WITHOUT RETINOPATHY.

    Science.gov (United States)

    Choi, WooJhon; Waheed, Nadia K; Moult, Eric M; Adhi, Mehreen; Lee, ByungKun; De Carlo, Talisa; Jayaraman, Vijaysekhar; Baumal, Caroline R; Duker, Jay S; Fujimoto, James G

    2017-01-01

    To investigate the utility of ultrahigh speed, swept source optical coherence tomography angiography in visualizing retinal microvascular and choriocapillaris (CC) changes in diabetic patients. The study was prospective and cross-sectional. A 1,050 nm wavelength, 400 kHz A-scan rate swept source optical coherence tomography prototype was used to perform volumetric optical coherence tomography angiography of the retinal and CC vasculatures in diabetic patients and normal subjects. Sixty-three eyes from 32 normal subjects, 9 eyes from 7 patients with proliferative diabetic retinopathy, 29 eyes from 16 patients with nonproliferative diabetic retinopathy, and 51 eyes from 28 diabetic patients without retinopathy were imaged. Retinal and CC microvascular abnormalities were observed in all stages of diabetic retinopathy. In nonproliferative diabetic retinopathy and proliferative diabetic retinopathy, optical coherence tomography angiography visualized a variety of vascular abnormalities, including clustered capillaries, dilated capillary segments, tortuous capillaries, regions of capillary dropout, reduced capillary density, abnormal capillary loops, and foveal avascular zone enlargement. In proliferative diabetic retinopathy, retinal neovascularization above the inner limiting membrane was visualized. Regions of CC flow impairment in patients with proliferative diabetic retinopathy and nonproliferative diabetic retinopathy were also observed. In 18 of the 51 of eyes from diabetic patients without retinopathy, retinal mircrovascular abnormalities were observed and CC flow impairment was found in 24 of the 51 diabetic eyes without retinopathy. The ability of optical coherence tomography angiography to visualize retinal and CC microvascular abnormalities suggests it may be a useful tool for understanding pathogenesis, evaluating treatment response, and earlier detection of vascular abnormalities in patients with diabetes.

  20. Optimisation of a polygon mirror-based spectral filter for swept source optical coherence tomography (SS-OCT)

    Science.gov (United States)

    Everson, Michael; Duma, Virgil-Florin; Dobre, George

    2018-03-01

    Medical imaging using Optical Coherence Tomography (OCT) provides clinicians with 3D, high resolution reconstructions of microscopic structures, in depth. It has been initially developed for ophthalmology, in order to scan the retinas of patients to diagnose illness. The quality of the images depends upon their axial and lateral resolutions and the properties of the light being used. Research using a polygon mirror (PM) as a spectral filter in Swept Source OCT (SS-OCT) has resulted in a variety of different experimental arrangements. Although the application of PM-based SS-OCT sources has been successfully demonstrated, the combination of their components' fundamental properties and the overall impact they have on imaging performance is rarely reported. A more detailed examination of these properties would lead to a full description of their operation and to the best methods to employ if system performance is to be maximised. This work presents our current findings of on-going research into the optimisation of PM-based SS-OCT systems. A swept source spectral filter, consisting of a collimator, a transmission grating, a two-lens telescope and an off-axis PM with an end reflector mirror has been evaluated experimentally and compared with theoretical predictions. The system's performance has been compared for two different fibre collimators. Although the beam width on the grating is different for each of the two collimators, the spot size at the PM facet is made the same by selecting appropriate focal lengths. An improvement in the signal roll-off at the interferometer output of 1.0 dB/mm was obtained when using a 3.4 mm collimator compared to a 1.5 mm collimator.

  1. Vertical distribution of pelagic photosynthesis

    DEFF Research Database (Denmark)

    Lyngsgaard, Maren Moltke

    chlorophyll maxima (DCM) to be a general feature in the ocean. Today, it is generally accepted that DCMs occur in most of our oceans still, despite this empirical knowledge, subsurface primary production is still largely ignored in marine science. The work included in this PhD examines the vertical...... each of the three regions combined with 15 years of survey data for the Baltic Sea transition zone. Overall, the results of this PhD work show that the vertical distribution of phytoplankton and their activity is important for the understanding, dynamics and functioning of pelagic ecosystems. It, thus......, emphasizes that future research and modelling exercises aimed at improving understanding of pelagic ecosystems and their role in the global ocean should include a consideration of the vertical heterogeneity in phytoplankton distributions and activity....

  2. Neglected locked vertical patellar dislocation

    Science.gov (United States)

    Gupta, Rakesh Kumar; Gupta, Vinay; Sangwan, Sukhbir Singh; Kamboj, Pradeep

    2012-01-01

    Patellar dislocations occurring about the vertical and horizontal axis are rare and irreducible. The neglected patellar dislocation is still rarer. We describe the clinical presentation and management of a case of neglected vertical patellar dislocation in a 6 year-old boy who sustained an external rotational strain with a laterally directed force to his knee. Initially the diagnosis was missed and 2 months later open reduction was done. The increased tension generated by the rotation of the lateral extensor retinaculum kept the patella locked in the lateral gutter even with the knee in full extension. Traumatic patellar dislocation with rotation around a vertical axis has been described earlier, but no such neglected case has been reported to the best of our knowledge. PMID:23162154

  3. Neglected locked vertical patellar dislocation

    Directory of Open Access Journals (Sweden)

    Rakesh Kumar Gupta

    2012-01-01

    Full Text Available Patellar dislocations occurring about the vertical and horizontal axis are rare and irreducible. The neglected patellar dislocation is still rarer. We describe the clinical presentation and management of a case of neglected vertical patellar dislocation in a 6 year-old boy who sustained an external rotational strain with a laterally directed force to his knee. Initially the diagnosis was missed and 2 months later open reduction was done. The increased tension generated by the rotation of the lateral extensor retinaculum kept the patella locked in the lateral gutter even with the knee in full extension. Traumatic patellar dislocation with rotation around a vertical axis has been described earlier, but no such neglected case has been reported to the best of our knowledge.

  4. Building a progressive vertical integration

    International Nuclear Information System (INIS)

    Charette, D.

    2008-01-01

    AAER Inc. is a Quebec-based company that manufactures turbines using proven European designs. This presentation discussed the company's business model. The company places an emphasis on identifying strategic and key components currently available for its turbines. Market analyses are performed in order to determine ideal suppliers and define business strategies and needs. The company invests in long-term relationships with its suppliers. Business partners for AAER are of a similar size and have a mutual understanding and respect for the company's business practices. Long-term agreements with suppliers are signed in order to ensure reliability and control over costs. Progressive vertical integration has been achieved by progressively manufacturing key components and integrating a North American supply chain. The company's secure supply chain and progressive vertical integration has significantly reduced financial costs and provided better quality control. It was concluded that vertical integration has also allowed AAER to provide better customer service and reduce transportation costs. tabs., figs

  5. Rhabdoviruses in two species of Drosophila: vertical transmission and a recent sweep.

    Science.gov (United States)

    Longdon, Ben; Wilfert, Lena; Obbard, Darren J; Jiggins, Francis M

    2011-05-01

    Insects are host to a diverse range of vertically transmitted micro-organisms, but while their bacterial symbionts are well-studied, little is known about their vertically transmitted viruses. We have found that two sigma viruses (Rhabdoviridae) recently discovered in Drosophila affinis and Drosophila obscura are both vertically transmitted. As is the case for the sigma virus of Drosophila melanogaster, we find that both males and females can transmit these viruses to their offspring. Males transmit lower viral titers through sperm than females transmit through eggs, and a lower proportion of their offspring become infected. In natural populations of D. obscura in the United Kingdom, we found that 39% of flies were infected and that the viral population shows clear evidence of a recent expansion, with extremely low genetic diversity and a large excess of rare polymorphisms. Using sequence data we estimate that the virus has swept across the United Kingdom within the past ∼11 years, during which time the viral population size doubled approximately every 9 months. Using simulations based on our lab estimates of transmission rates, we show that the biparental mode of transmission allows the virus to invade and rapidly spread through populations at rates consistent with those measured in the field. Therefore, as predicted by our simulations, the virus has undergone an extremely rapid and recent increase in population size. In light of this and earlier studies of a related virus in D. melanogaster, we conclude that vertically transmitted rhabdoviruses may be common in insects and that these host-parasite interactions can be highly dynamic.

  6. Rhabdoviruses in Two Species of Drosophila: Vertical Transmission and a Recent Sweep

    Science.gov (United States)

    Longdon, Ben; Wilfert, Lena; Obbard, Darren J.; Jiggins, Francis M.

    2011-01-01

    Insects are host to a diverse range of vertically transmitted micro-organisms, but while their bacterial symbionts are well-studied, little is known about their vertically transmitted viruses. We have found that two sigma viruses (Rhabdoviridae) recently discovered in Drosophila affinis and Drosophila obscura are both vertically transmitted. As is the case for the sigma virus of Drosophila melanogaster, we find that both males and females can transmit these viruses to their offspring. Males transmit lower viral titers through sperm than females transmit through eggs, and a lower proportion of their offspring become infected. In natural populations of D. obscura in the United Kingdom, we found that 39% of flies were infected and that the viral population shows clear evidence of a recent expansion, with extremely low genetic diversity and a large excess of rare polymorphisms. Using sequence data we estimate that the virus has swept across the United Kingdom within the past ∼11 years, during which time the viral population size doubled approximately every 9 months. Using simulations based on our lab estimates of transmission rates, we show that the biparental mode of transmission allows the virus to invade and rapidly spread through populations at rates consistent with those measured in the field. Therefore, as predicted by our simulations, the virus has undergone an extremely rapid and recent increase in population size. In light of this and earlier studies of a related virus in D. melanogaster, we conclude that vertically transmitted rhabdoviruses may be common in insects and that these host–parasite interactions can be highly dynamic. PMID:21339477

  7. Hybrid Vertical-Cavity Laser

    DEFF Research Database (Denmark)

    2010-01-01

    The present invention provides a light source (2) for light circuits on a silicon platform (3). A vertical laser cavity is formed by a gain region (101) arranged between a top mirror (4) and a bottom grating-mirror (12) in a grating region (11) in a silicon layer (10) on a substrate. A waveguide...... (18, 19) for receiving light from the grating region (11) is formed within or to be connected to the grating region, and functions as an 5 output coupler for the VCL. Thereby, vertical lasing modes (16) are coupled to lateral in-plane modes (17, 20) of the in-plane waveguide formed in the silicon...

  8. Vertical reactor coolant pump instabilities

    International Nuclear Information System (INIS)

    Jones, R.M.

    1985-01-01

    The investigation conducted at the Tennessee Valley Authority's Sequoyah Nuclear Power Plant to determine and correct increasing vibrations in the vertical reactor coolant pumps is described. Diagnostic procedures to determine the vibration causes and evaluate the corractive measures taken are also described

  9. Vertical integration and optimal reimbursement policy.

    Science.gov (United States)

    Afendulis, Christopher C; Kessler, Daniel P

    2011-09-01

    Health care providers may vertically integrate not only to facilitate coordination of care, but also for strategic reasons that may not be in patients' best interests. Optimal Medicare reimbursement policy depends upon the extent to which each of these explanations is correct. To investigate, we compare the consequences of the 1997 adoption of prospective payment for skilled nursing facilities (SNF PPS) in geographic areas with high versus low levels of hospital/SNF integration. We find that SNF PPS decreased spending more in high integration areas, with no measurable consequences for patient health outcomes. Our findings suggest that integrated providers should face higher-powered reimbursement incentives, i.e., less cost-sharing. More generally, we conclude that purchasers of health services (and other services subject to agency problems) should consider the organizational form of their suppliers when choosing a reimbursement mechanism.

  10. Vertical and lateral horizontal forces of walking area running pedestrians

    Czech Academy of Sciences Publication Activity Database

    Urushadze, Shota; Pirner, Miroš

    2016-01-01

    Roč. 2, č. 1 (2016), s. 38-50 ISSN 2149-8024 R&D Projects: GA ČR(CZ) GA15-01035S Institutional support: RVO:68378297 Keywords : stride strength * stride frequency * step frequency * dynamic coefficient * effects of striding velocity Subject RIV: JM - Building Engineering http://www.challengejournal.com/index.php/cjsmec/article/view/54

  11. Vertical Cable Seismic Survey for Hydrothermal Deposit

    Science.gov (United States)

    Asakawa, E.; Murakami, F.; Sekino, Y.; Okamoto, T.; Ishikawa, K.; Tsukahara, H.; Shimura, T.

    2012-04-01

    The vertical cable seismic is one of the reflection seismic methods. It uses hydrophone arrays vertically moored from the seafloor to record acoustic waves generated by surface, deep-towed or ocean bottom sources. Analyzing the reflections from the sub-seabed, we could look into the subsurface structure. This type of survey is generally called VCS (Vertical Cable Seismic). Because VCS is an efficient high-resolution 3D seismic survey method for a spatially-bounded area, we proposed the method for the hydrothermal deposit survey tool development program that the Ministry of Education, Culture, Sports, Science and Technology (MEXT) started in 2009. We are now developing a VCS system, including not only data acquisition hardware but data processing and analysis technique. Our first experiment of VCS surveys has been carried out in Lake Biwa, JAPAN in November 2009 for a feasibility study. Prestack depth migration is applied to the 3D VCS data to obtain a high quality 3D depth volume. Based on the results from the feasibility study, we have developed two autonomous recording VCS systems. After we carried out a trial experiment in the actual ocean at a water depth of about 400m and we carried out the second VCS survey at Iheya Knoll with a deep-towed source. In this survey, we could establish the procedures for the deployment/recovery of the system and could examine the locations and the fluctuations of the vertical cables at a water depth of around 1000m. The acquired VCS data clearly shows the reflections from the sub-seafloor. Through the experiment, we could confirm that our VCS system works well even in the severe circumstances around the locations of seafloor hydrothermal deposits. We have, however, also confirmed that the uncertainty in the locations of the source and of the hydrophones could lower the quality of subsurface image. It is, therefore, strongly necessary to develop a total survey system that assures a accurate positioning and a deployment techniques

  12. Vertically aligned carbon nanotube field-effect transistors

    KAUST Repository

    Li, Jingqi

    2012-10-01

    Vertically aligned carbon nanotube field-effect transistors (CNTFETs) have been developed using pure semiconducting carbon nanotubes. The source and drain were vertically stacked, separated by a dielectric, and the carbon nanotubes were placed on the sidewall of the stack to bridge the source and drain. Both the effective gate dielectric and gate electrode were normal to the substrate surface. The channel length is determined by the dielectric thickness between source and drain electrodes, making it easier to fabricate sub-micrometer transistors without using time-consuming electron beam lithography. The transistor area is much smaller than the planar CNTFET due to the vertical arrangement of source and drain and the reduced channel area. © 2012 Elsevier Ltd. All rights reserved.

  13. Estimating Vertical Land Motion in the Chesapeake Bay

    Science.gov (United States)

    Houttuijn Bloemendaal, L.; Hensel, P.

    2017-12-01

    This study aimed to provide a modern measurement of subsidence in the Chesapeake Bay region and establish a methodology for measuring vertical land motion using static GPS, a cheaper alternative to InSAR or classical leveling. Vertical land motion in this area is of particular concern because tide gages are showing up to 5 mm/yr of local, relative sea level rise. While a component of this rate is the actual eustatic sea level rise itself, part of the trend may also be vertical land motion, in which subsidence exacerbates the effects of actual changes in sea level. Parts of this region are already experiencing an increase in the frequency and magnitude of near-shore coastal flooding, but the last comprehensive study of vertical land motion in this area was conducted by NOAA in 1974 (Holdahl & Morrison) using repeat leveled lines. More recent measures of vertical land motion can help inform efforts on resilience to sea level rise, such as in the Hampton Roads area. This study used measured GPS-derived vertical heights in conjunction with legacy GPS data to calculate rates of vertical motion at several points in time for a selection of benchmarks scattered throughout the region. Seventeen marks in the stable Piedmont area and in the areas suspected of subsidence in the Coastal Plain were selected for the analysis. Results indicate a significant difference between the rates of vertical motion in the Piedmont and Coastal Plain, with a mean rate of -4.10 mm/yr in the Coastal Plain and 0.15 mm/yr in the Piedmont. The rates indicate particularly severe subsidence at the southern Delmarva Peninsula coast and the Hampton-Roads area, with a mean rate of -6.57 mm/yr in that region. By knowing local rates of subsidence as opposed to sea level change itself, coastal managers may make better informed decisions regarding natural resource use, such as deciding whether or not to reduce subsurface fluid withdrawals or to consider injecting treated water back into the aquifer to slow

  14. Comparison of retina specialist preferences regarding spectral-domain and swept-source optical coherence tomography angiography

    Directory of Open Access Journals (Sweden)

    Su GL

    2017-05-01

    Full Text Available Grace L Su,1 Douglas M Baughman,2 Qinqin Zhang,3 Kasra Rezaei,2 Aaron Y Lee,2 Cecilia S Lee2 1Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 2Department of Ophthalmology, 3Department of Bioengineering, University of Washington, Seattle, WA, USA Purpose: The aim of this study was to compare physician preferences regarding the commercially available spectral-domain (SD optical coherence tomography angiography (OCTA and swept-source (SS OCTA prototype device.Design: Comparative analysis of diagnostic instruments was performed.Patients and methods: Subjects at the University of Washington Eye Institute and Harborview Medical Center were prospectively recruited and imaged with the Zeiss SD OCTA (HD-5000, Angioplex and Zeiss SS OCTA (Plex Elite, Everest devices on the same day. The study included 10 eyes from 10 subjects diagnosed with a retinal/choroidal disease. Deidentified images were compiled into a survey and sent to retina specialists in various countries. The survey presented masked SD and SS images of each eye for each retinal sublayer side by side. Respondents were asked about their image preference and impact on clinical management. A priori and post hoc preferences for SD vs SS were collected.Results: Fifty-four retina specialists responded to the survey. Median years in practice was 3.00 (interquartile range [IQR] 1.50–17.00. At baseline, 23 (48% physicians owned an OCTA machine. The majority of physician responses showed a preference for the SS over SD OCTA, independent of the retinal pathology shown (n=454 overall responses, 74%. Nevertheless, the majority indicated that both SD and SS would be equally valuable in informing clinical decisions (n=374 overall responses, 61%.Conclusion: These findings indicate that the majority of retina specialists surveyed prefer SS over SD OCTA based on image quality, regardless of the retinal pathology shown. Regarding the clinical utility of each modality, the majority of

  15. Coexistence of Strategic Vertical Separation and Integration

    DEFF Research Database (Denmark)

    Jansen, Jos

    2003-01-01

    This paper gives conditions under which vertical separation is chosen by some upstream firms, while vertical integration is chosen by others in the equilibrium of a symmetric model. A vertically separating firm trades off fixed contracting costs against the strategic benefit of writing a (two......-part tariff, exclusive dealing) contract with its retailer. Coexistence emerges when more than two vertical Cournot oligopolists supply close substitutes. When vertical integration and separation coexist, welfare could be improved by reducing the number of vertically separating firms. The scope...

  16. Demonstration of an Enhanced Vertical Magnetic Gradient System for UXO

    Science.gov (United States)

    2008-12-01

    fluxgate magnetometers , data recording console, laser altimeter, and acoustic altimeters were tested to ensure proper operation and performance. The VG...Simultaneous Electromagnetic Induction and Magnetometer System WAA wide area assessment ACKNOWLEDGEMENTS We wish to express our sincere...sensors. The benefits of vertical gradient (VG) configurations in magnetometer systems are common knowledge, and these configurations are routinely

  17. Viral lysis of marine microbes in relation to vertical stratification

    NARCIS (Netherlands)

    Mojica, K.D.A.

    2015-01-01

    The overall aim of this thesis is to investigate how changes in vertical stratification affect autotrophic and heterotrophic microbial communities along a meridional gradient in the Atlantic Ocean. The Northeast Atlantic Ocean is a key area in global ocean circulation and a important sink for

  18. Vertical and lateral heterogeneous integration

    Science.gov (United States)

    Geske, Jon; Okuno, Yae L.; Bowers, John E.; Jayaraman, Vijay

    2001-09-01

    A technique for achieving large-scale monolithic integration of lattice-mismatched materials in the vertical direction and the lateral integration of dissimilar lattice-matched structures has been developed. The technique uses a single nonplanar direct-wafer-bond step to transform vertically integrated epitaxial structures into lateral epitaxial variation across the surface of a wafer. Nonplanar wafer bonding is demonstrated by integrating four different unstrained multi-quantum-well active regions lattice matched to InP on a GaAs wafer surface. Microscopy is used to verify the quality of the bonded interface, and photoluminescence is used to verify that the bonding process does not degrade the optical quality of the laterally integrated wells. The authors propose this technique as a means to achieve greater levels of wafer-scale integration in optical, electrical, and micromechanical devices.

  19. Kinematic Fitting of Detached Vertices

    Energy Technology Data Exchange (ETDEWEB)

    Mattione, Paul [Rice Univ., Houston, TX (United States)

    2007-05-01

    The eg3 experiment at the Jefferson Lab CLAS detector aims to determine the existence of the $\\Xi_{5}$ pentaquarks and investigate the excited $\\Xi$ states. Specifically, the exotic $\\Xi_{5}^{--}$ pentaquark will be sought by first reconstructing the $\\Xi^{-}$ particle through its weak decays, $\\Xi^{-}\\to\\pi^{-}\\Lambda$ and $\\Lambda\\to\\pi^{-}$. A kinematic fitting routine was developed to reconstruct the detached vertices of these decays, where confidence level cuts on the fits are used to remove background events. Prior to fitting these decays, the exclusive reaction $\\gamma D\\rightarrow pp\\pi^{-}$ was studied in order to correct the track measurements and covariance matrices of the charged particles. The $\\Lambda\\rightarrow p\\pi^{-}$ and $\\Xi^{-}\\to\\pi^{-}\\Lambda$ decays were then investigated to demonstrate that the kinematic fitting routine reconstructs the decaying particles and their detached vertices correctly.

  20. Interference Lithography for Vertical Photovoltaics

    Science.gov (United States)

    Balls, Amy; Pei, Lei; Kvavle, Joshua; Sieler, Andrew; Schultz, Stephen; Linford, Matthew; Vanfleet, Richard; Davis, Robert

    2009-10-01

    We are exploring low cost approaches for fabricating three dimensional nanoscale structures. These vertical structures could significantly improve the efficiency of devices made from low cost photovoltaic materials. The nanoscale vertical structure provides a way to increase optical absorption in thin photovoltaic films without increasing the electronic carrier separation distance. The target structure is a high temperature transparent template with a dense array of holes on a 400 - 600 nm pitch fabricated by a combination of interference lithography and nanoembossing. First a master was fabricated using ultraviolet light interference lithography and the pattern was transferred into a silicon wafer master by silicon reactive ion etching. Embossing studies were performed with the master on several high temperature polymers.

  1. Vertically Integrated Circuits at Fermilab

    International Nuclear Information System (INIS)

    Deptuch, Grzegorz; Demarteau, Marcel; Hoff, James; Lipton, Ronald; Shenai, Alpana; Trimpl, Marcel; Yarema, Raymond; Zimmerman, Tom

    2009-01-01

    The exploration of the vertically integrated circuits, also commonly known as 3D-IC technology, for applications in radiation detection started at Fermilab in 2006. This paper examines the opportunities that vertical integration offers by looking at various 3D designs that have been completed by Fermilab. The emphasis is on opportunities that are presented by through silicon vias (TSV), wafer and circuit thinning and finally fusion bonding techniques to replace conventional bump bonding. Early work by Fermilab has led to an international consortium for the development of 3D-IC circuits for High Energy Physics. The consortium has submitted over 25 different designs for the Fermilab organized MPW run organized for the first time.

  2. Vertical Launch System Loadout Planner

    Science.gov (United States)

    2015-03-01

    United States Navy USS United States’ Ship VBA Visual Basic for Applications VLP VLS Loadout Planner VLS Vertical Launch System...with 32 gigabytes of random access memory and eight processors, General Algebraic Modeling System (GAMS) CPLEX version 24 (GAMS, 2015) solves this...problem in ten minutes to an integer tolerance of 10%. The GAMS interpreter and CPLEX solver require 75 Megabytes of random access memory for this

  3. NASA-Ames vertical gun

    Science.gov (United States)

    Schultz, P. H.

    1984-01-01

    A national facility, the NASA-Ames vertical gun range (AVGR) has an excellent reputation for revealing fundamental aspects of impact cratering that provide important constraints for planetary processes. The current logistics in accessing the AVGR, some of the past and ongoing experimental programs and their relevance, and the future role of this facility in planetary studies are reviewed. Publications resulting from experiments with the gun (1979 to 1984) are listed as well as the researchers and subjects studied.

  4. Strategic Inventories in Vertical Contracts

    OpenAIRE

    Krishnan Anand; Ravi Anupindi; Yehuda Bassok

    2008-01-01

    Classical reasons for carrying inventory include fixed (nonlinear) production or procurement costs, lead times, nonstationary or uncertain supply/demand, and capacity constraints. The last decade has seen active research in supply chain coordination focusing on the role of incentive contracts to achieve first-best levels of inventory. An extensive literature in industrial organization that studies incentives for vertical controls largely ignores the effect of inventories. Does the ability to ...

  5. Nerve Fiber Flux Analysis Using Wide-Field Swept-Source Optical Coherence Tomography.

    Science.gov (United States)

    Tan, Ou; Liu, Liang; Liu, Li; Huang, David

    2018-02-01

    To devise a method to quantify nerve fibers over their arcuate courses over an extended peripapillary area using optical coherence tomography (OCT). Participants were imaged with 8 × 8-mm volumetric OCT scans centered at the optic disc. A new quantity, nerve fiber flux (NFF), represents the cross-sectional area transected perpendicular to the nerve fibers. The peripapillary area was divided into 64 tracks with equal flux. An iterative algorithm traced the trajectory of the tracks assuming that the relative distribution of the NFF was conserved with compensation for fiber connections to ganglion cells on the macular side. Average trajectory was averaged from normal eyes and use to calculate the NFF maps for glaucomatous eyes. The NFF maps were divided into eight sectors that correspond to visual field regions. There were 24 healthy and 10 glaucomatous eyes enrolled. The algorithm converged on similar patterns of NFL tracks for all healthy eyes. In glaucomatous eyes, NFF correlated with visual field sensitivity in the arcuate sectors (Spearman ρ = 0.53-0.62). Focal nerve fiber loss in glaucomatous eyes appeared as uniform tracks of NFF defects that followed the expected arcuate fiber trajectory. Using an algorithm based on the conservation of flux, we derived nerve fiber trajectories in the peripapillary area. The NFF map is useful for the visualization of focal defects and quantification of sector nerve fiber loss from wide-area volumetric OCT scans. NFF provides a cumulative measure of volumetric loss along nerve fiber tracks and could improve the detection of focal glaucoma damage.

  6. Numerical Analysis and Geometry Optimisation of Vertical Vane of Room Air-conditioner

    Directory of Open Access Journals (Sweden)

    Al-Obaidi Abdulkareem Sh. Mahdi

    2018-01-01

    Full Text Available Vertical vanes of room air-conditioners are used to control and direct cold air. This paper aims to study vertical vane as one of the parameters that affect the efficiency of dissipating cold air to a given space. The vertical vane geometry is analysed and optimised for lower production cost using CFD. The optimised geometry of the vertical vane should have the same or increased efficiency of dissipating cold air and have lesser mass compared to the existing original design. The existing original design of vertical vane is simplified and analysed by using ANSYS Fluent. Efficiency of wind direction is define as how accurate the direction of airflow coming out from vertical vane. In order to calculate the efficiency of wind direction, 15° and 30° rotation of vertical vane inside room air-conditioner are simulated. The efficiency of wind direction for 15° rotation of vertical vane is 57.81% while efficiency of wind direction for 30° rotation of vertical vane is 47.54%. The results of the efficiency of wind direction are used as base reference for parametric study. The parameters investigated for optimisation of vertical vane are focused at length of long span, tip chord and short span. The design of 15% decreased in vane surface area at tip chord is the best optimised design of vertical vane because the efficiency of wind direction is the highest as 60.32%.

  7. Silver nanoparticles (AgNPs) as a contrast agent for imaging of animal tissue using swept-source optical coherence tomography (SSOCT)

    Science.gov (United States)

    Mondal, Indranil; Raj, Shipra; Roy, Poulomi; Poddar, Raju

    2018-01-01

    We present noninvasive three-dimensional depth-resolved imaging of animal tissue with a swept-source optical coherence tomography system at 1064 nm center wavelength and silver nanoparticles (AgNPs) as a potential contrast agent. A swept-source laser light source is used to enable an imaging rate of 100 kHz (100 000 A-scans s-1). Swept-source optical coherence tomography is a new variant of the optical coherence tomography (OCT) technique, offering unique advantages in terms of sensitivity, reduction of motion artifacts, etc. To enhance the contrast of an OCT image, AgNPs are utilized as an exogeneous contrast agent. AgNPs are synthesized using a modified Tollens method and characterization is done by UV-vis spectroscopy, dynamic light scattering, scanning electron microscopy and energy dispersive x-ray spectroscopy. In vitro imaging of chicken breast tissue, with and without the application of AgNPs, is performed. The effect of AgNPs is studied with different exposure times. A mathematical model is also built to calculate changes in the local scattering coefficient of tissue from OCT images. A quantitative estimation of scattering coefficient and contrast is performed for tissues with and without application of AgNPs. Significant improvement in contrast and increase in scattering coefficient with time is observed.

  8. High-performance vertical organic transistors.

    Science.gov (United States)

    Kleemann, Hans; Günther, Alrun A; Leo, Karl; Lüssem, Björn

    2013-11-11

    Vertical organic thin-film transistors (VOTFTs) are promising devices to overcome the transconductance and cut-off frequency restrictions of horizontal organic thin-film transistors. The basic physical mechanisms of VOTFT operation, however, are not well understood and VOTFTs often require complex patterning techniques using self-assembly processes which impedes a future large-area production. In this contribution, high-performance vertical organic transistors comprising pentacene for p-type operation and C60 for n-type operation are presented. The static current-voltage behavior as well as the fundamental scaling laws of such transistors are studied, disclosing a remarkable transistor operation with a behavior limited by injection of charge carriers. The transistors are manufactured by photolithography, in contrast to other VOTFT concepts using self-assembled source electrodes. Fluorinated photoresist and solvent compounds allow for photolithographical patterning directly and strongly onto the organic materials, simplifying the fabrication protocol and making VOTFTs a prospective candidate for future high-performance applications of organic transistors. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Ultra-compact swept-source optical coherence tomography handheld probe with motorized focus adjustment (Conference Presentation)

    Science.gov (United States)

    LaRocca, Francesco; Nankivil, Derek; Keller, Brenton; Farsiu, Sina; Izatt, Joseph A.

    2017-02-01

    Handheld optical coherence tomography (OCT) systems facilitate imaging of young children, bedridden subjects, and those with less stable fixation. Smaller and lighter OCT probes allow for more efficient imaging and reduced operator fatigue, which is critical for prolonged use in either the operating room or neonatal intensive care unit. In addition to size and weight, the imaging speed, image quality, field of view, resolution, and focus correction capability are critical parameters that determine the clinical utility of a handheld probe. Here, we describe an ultra-compact swept source (SS) OCT handheld probe weighing only 211 g (half the weight of the next lightest handheld SSOCT probe in the literature) with 20.1 µm lateral resolution, 7 µm axial resolution, 102 dB peak sensitivity, a 27° x 23° field of view, and motorized focus adjustment for refraction correction between -10 to +16 D. A 2D microelectromechanical systems (MEMS) scanner, a converging beam-at-scanner telescope configuration, and an optical design employing 6 different custom optics were used to minimize device size and weight while achieving diffraction limited performance throughout the system's field of view. Custom graphics processing unit (GPU)-accelerated software was used to provide real-time display of OCT B-scans and volumes. Retinal images were acquired from adult volunteers to demonstrate imaging performance.

  10. Swept source optical coherence tomography for in vivo imaging and vibrometry in the apex of the mouse cochlea

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hee Yoon [E.L. Ginzton Laboratory and Department of Electrical Engineering, Stanford University, Stanford, California (United States); Department of Otolaryngology-Head and Neck Surgery, Stanford University, Stanford, California (United States); Raphael, Patrick D.; Oghalai, John S. [Department of Otolaryngology-Head and Neck Surgery, Stanford University, Stanford, California (United States); Ellerbee, Audrey K. [E.L. Ginzton Laboratory and Department of Electrical Engineering, Stanford University, Stanford, California (United States); Applegate, Brian E. [Department of Biomedical Engineering, Texas A& M University, College Station, Texas (United States)

    2015-12-31

    Cochlear amplification has been most commonly investigated by measuring the vibrations of the basilar membrane in animal models. Several different techniques have been used for measuring these vibrations such as laser Doppler vibrometry, miniature pressure sensors, low coherence interferometry, and spectral-domain optical coherence tomography (SD-OCT). We have built a swept-source OCT (SS-OCT) system, which is similar to SD-OCT in that it is capable of performing both imaging and vibration measurements within the mouse cochlea in vivo without having to open the bone. In vivo 3D images of a mouse cochlea were obtained, and the basilar membrane, tectorial membrane, Reissner’s membrane, tunnel of Corti, and reticular lamina could all be resolved. We measured vibrations of multiple structures within the mouse cochlea to sound stimuli. As well, we measured the radial deflections of the reticular lamina and tectorial membrane to estimate the displacement of the outer hair cell stereocilia. These measurements have the potential to more clearly define the mechanisms underlying the linear and non-linear processes within the mammalian cochlea.

  11. Measurements of plasma profiles using a fast swept Langmuir probe in the VINETA-II magnetic reconnection experiment

    Science.gov (United States)

    Shesterikov, I.; Von Stechow, A.; Grulke, O.; Stenzel, R.; Klinger, T.

    2017-07-01

    A fast-swept Langmuir probe capable to be biased at a high voltages has been constructed and successfully operated at the VINETA-II magnetic reconnection experiment. The presented circuit has two main features beneficial for fast transient parameter changes in laboratory experiments as, e.g., plasma guns or magnetic reconnection: the implementation simplicity and the high voltage sweep range. This work presents its design and performance for time-dependent measurements of VINETA-II plasmas. The probe is biased with a sinusoidal voltage at a fixed frequency. Current - voltage characteristics are measured along the falling and rising slopes of the probe bias. The sweep frequency is fsweep= 150 kHz. The spatiotemporal evolution of radial plasma profiles is obtained by evaluation of the probe characteristics. The plasma density measurements agree with those derived from a microwave interferometer, demonstrating the reliability of the measurements. As a model plasma system, a plasma gun discharge with typical pulse times of 60 μ s is chosen.

  12. The Effect of Acoustic Forcing on Instabilities and Breakdown in Swept-Wing Flow over a Backward-Facing Step

    Science.gov (United States)

    Eppink, Jenna L.; Shishkov, Olga; Wlezien, Richard W.; King, Rudolph A.; Choudhari, Meelan

    2016-01-01

    Instability interaction and breakdown were experimentally investigated in the flow over a swept backward-facing step. Acoustic forcing was used to excite the Tollmien-Schlichting (TS) instability and to acquire phase-locked results. The phase-averaged results illustrate the complex nature of the interaction between the TS and stationary cross flow instabilities. The weak stationary cross flow disturbance causes a distortion of the TS wavefront. The breakdown process is characterized by large positive and negative spikes in velocity. The positive spikes occur near the same time and location as the positive part of the TS wave. Higher-order spectral analysis was used to further investigate the nonlinear interactions between the TS instability and the traveling cross flow disturbances. The results reveal that a likely cause for the generation of the spikes corresponds to nonlinear interactions between the TS, traveling cross flow, and stationary cross flow disturbances. The spikes begin at low amplitudes of the unsteady and steady disturbances (2-4% U (sub e) (i.e. boundary layer edge velocity)) but can achieve very large amplitudes (20-30 percent U (sub e) (i.e. boundary layer edge velocity)) that initiate an early, though highly intermittent, breakdown to turbulence.

  13. Assessment of corneal dynamics with high-speed swept source Optical Coherence Tomography combined with an air puff system

    Science.gov (United States)

    Alonso-Caneiro, David; Karnowski, Karol; Kaluzny, Bartlomiej J.; Kowalczyk, Andrzej; Wojtkowski, Maciej

    2011-07-01

    We present a novel method and instrument for in vivo imaging and measurement of the human corneal dynamics during an air puff. The instrument is based on high-speed swept source optical coherence tomography (ssOCT) combined with a custom adapted air puff chamber from a non-contact tonometer, which uses an air stream to deform the cornea in a non-invasive manner. During the short period of time that the deformation takes place, the ssOCT acquires multiple A-scans in time (M-scan) at the center of the air puff, allowing observation of the dynamics of the anterior and posterior corneal surfaces as well as the anterior lens surface. The dynamics of the measurement are driven by the biomechanical properties of the human eye as well as its intraocular pressure. Thus, the analysis of the M-scan may provide useful information about the biomechanical behavior of the anterior segment during the applanation caused by the air puff. An initial set of controlled clinical experiments are shown to comprehend the performance of the instrument and its potential applicability to further understand the eye biomechanics and intraocular pressure measurements. Limitations and possibilities of the new apparatus are discussed.

  14. Rapid and Sensitive Quantification of Isotopic Mixtures Using a Rapidly-Swept External Cavity Quantum Cascade Laser

    Directory of Open Access Journals (Sweden)

    Brian E. Brumfield

    2016-05-01

    Full Text Available A rapidly-swept external-cavity quantum cascade laser with an open-path Herriott cell is used to quantify gas-phase chemical mixtures of D2O and HDO at a rate of 40 Hz (25-ms measurement time. The chemical mixtures were generated by evaporating D2O liquid near the open-path Herriott cell, allowing the H/D exchange reaction with ambient H2O to produce HDO. Fluctuations in the ratio of D2O and HDO on timescales of <1 s due to the combined effects of plume transport and the H/D exchange chemical reaction are observed. Noise-equivalent concentrations (1σ (NEC of 147.0 ppbv and 151.6 ppbv in a 25-ms measurement time are determined for D2O and HDO, respectively, with a 127-m optical path. These NECs are improved to 23.0 and 24.0 ppbv with a 1-s averaging time for D2O and HDO, respectively. NECs <200 ppbv are also estimated for N2O, 1,1,1,2–tetrafluoroethane (F134A, CH4, acetone and SO2 for a 25-ms measurement time. The isotopic precision for measurement of the [D2O]/[HDO] concentration ratio of 33‰ and 5‰ is calculated for the current experimental conditions for measurement times of 25 ms and 1 s, respectively.

  15. Precision and broadband frequency swept laser source based on high-order modulation-sideband injection-locking.

    Science.gov (United States)

    Wei, Fang; Lu, Bin; Wang, Jian; Xu, Dan; Pan, Zhengqing; Chen, Dijun; Cai, Haiwen; Qu, Ronghui

    2015-02-23

    A precision and broadband laser frequency swept technique is experimentally demonstrated. Using synchronous current compensation, a slave diode laser is dynamically injection-locked to a specific high-order modulation-sideband of a narrow-linewidth master laser modulated by an electro-optic modulator (EOM), whose driven radio frequency (RF) signal can be agilely, precisely controlled by a frequency synthesizer, and the high-order modulation-sideband enables multiplied sweep range and tuning rate. By using 5th order sideband injection-locking, the original tuning range of 3 GHz and tuning rate of 0.5 THz/s is multiplied by 5 times to 15 GHz and 2.5 THz/s respectively. The slave laser has a 3 dB-linewidth of 2.5 kHz which is the same to the master laser. The settling time response of a 10 MHz frequency switching is 2.5 µs. By using higher-order modulation-sideband and optimized experiment parameters, an extended sweep range and rate could be expected.

  16. Thermal and chemical modifications on a low rank coal by iron addition in swept fixed by hydropyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Mastral, A.M.; Perez-Surio, M.J.; Palacios, J.M. [CSIC, Zaragoza (Spain). Inst. de Carboquimica

    1998-05-01

    The paper discusses the thermal and chemical changes taking place on a low rank coal when it is subjected to hydropyrolysis conditions with Red Mud as the catalytic precursor. For each run, 5 g of coal were pyrolysed in a swept fixed bed reactor at 40 kg/cm{sup 2} hydrogen pressure. The variables of the process were: temperatures ranging from 400 to 600{degree}C; 0.5 and 2 l/min of hydrogen flow; 10 and 30 min residence time; and in the presence and absence of Red Mud. Conversion products distribution and a wide battery of complementary analyses allow information to be gathered regarding the changes undergone by the coal structure, both in its organic and inorganic components, in its conversion into liquids and chars. From the data obtained, it can be deduced that: (1) at 400{degree}C the iron catalyst is not active; (2) at higher temperatures iron catalytic cracking is observed more than hydrogenating activity, due to the Fe{sub 2}O{sub 3} transformation into (Fe{sub 3}S{sub 4}) crystallographically as spinel; (3) in this coal hydropyrolysis one third of the coal is converted into liquids; and (4) Red Mud helps to reduce sulfur emissions by H{sub 2}S fixation as Fe{sub 3}S{sub 4}. 10 refs., 5 figs., 5 tabs.

  17. Comparison of choroidal thickness using swept-source and spectral-domain optical coherence tomography in normal Indian eyes.

    Science.gov (United States)

    Narendran, Siddharth; Manayath, George; Venkatapathy, Narendran

    2018-01-01

    Choroidal thickness measurements are reported to differ between spectral-domain optical coherence tomography (SD-OCT) and swept-source OCT (SS-OCT). The aim of this study was to assess the comparability of choroidal thickness measurements using SS-OCT and SD-OCT devices among normal participants. This was a prospective study of 31 (62 eyes) normal participants. Choroidal imaging was performed sequentially with the Spectralis OCT (SD-OCT) and the deep range imaging OCT (DRI OCT-1) (SS-OCT) using standardized imaging protocols. The subfoveal choroidal thickness (SFChT) was measured manually by two masked retinal specialists. Paired t -tests and intraclass correlation coefficients (ICCs) were used to compare the measurements. The mean SFChT was 319.5 μm and 325.3 μm for DRI OCT-1 and Spectralis OCT, respectively ( P = 0.001), with a mean difference of 5.9 with ICC of 0.97. The mean difference in choroidal thickness between the OCT devices was larger among eyes with choroidal thickness > 350 μm compared with eyes with thinner choroids (8.0 μm vs. 4.7 μm). SFChT measurements are comparable between DRI OCT-1 and Spectralis OCT. The variability between the devices increases in thicker choroids.

  18. Repeatability of swept-source optical coherence tomography retinal and choroidal thickness measurements in neovascular age-related macular degeneration

    DEFF Research Database (Denmark)

    Hanumunthadu, Daren; Ilginis, Tomas; Restori, Marie

    2017-01-01

    BACKGROUND: The aim was to determine the intrasession repeatability of swept-source optical coherence tomography (SS-OCT)-derived retinal and choroidal thickness measurements in eyes with neovascular age-related macular degeneration (nAMD). METHODS: A prospective study consisting of patients...... with active nAMD enrolled in the Distance of Choroid Study at Moorfields Eye Hospital, London. Patients underwent three 12×9 mm macular raster scans using the deep range imaging (DRI) OCT-1 SS-OCT (Topcon) device in a single imaging session. Retinal and choroidal thicknesses were calculated for the ETDRS...... macular subfields. Repeatability was calculated according to methods described by Bland and Altman. RESULTS: 39 eyes of 39 patients with nAMD were included with a mean (±SD) age of 73.9 (±7.2) years. The mean (±SD) retinal thickness of the central macular subfield was 225.7 μm (±12.4 μm...

  19. [Vertical fractures: apropos of 2 clinical cases].

    Science.gov (United States)

    Félix Mañes Ferrer, J; Micò Muñoz, P; Sánchez Cortés, J L; Paricio Martín, J J; Miñana Laliga, R

    1991-01-01

    The aim of the study is to present a clinical review of the vertical root fractures. Two clinical cases are presented to demonstrates the criteria for obtaining a correct diagnosis of vertical root fractures.

  20. Vertical melting of a stack of membranes

    Science.gov (United States)

    Borelli, M. E. S.; Kleinert, H.; Schakel, A. M. J.

    2001-02-01

    A stack of tensionless membranes with nonlinear curvature energy and vertical harmonic interaction is studied. At low temperatures, the system forms a lamellar phase. At a critical temperature, the stack disorders vertically in a melting-like transition.

  1. VERTICAL ACTIVITY ESTIMATION USING 2D RADAR

    African Journals Online (AJOL)

    hennie

    estimates on aircraft vertical behaviour from a single 2D radar track. ... Fortunately, the problem of detecting relative vertical motion using a single 2D ..... awareness tools in scenarios where aerial activity sensing is typically limited to 2D.

  2. Vertical structures in vibrated wormlike micellar solutions

    Science.gov (United States)

    Epstein, Tamir; Deegan, Robert

    2008-11-01

    Vertically vibrated shear thickening particulate suspensions can support a free-standing interfaces oriented parallel to gravity. We find that shear thickening worm-like micellar solutions also support such vertical interfaces. Above a threshold in acceleration, the solution spontaneously accumulates into a labyrinthine pattern characterized by a well-defined vertical edge. The formation of vertical structures is of interest because they are unique to shear-thickening fluids, and they indicate the existence of an unknown stress bearing mechanism.

  3. Vertical sounding balloons for stratospheric photochemistry

    Science.gov (United States)

    Pommereau, J. P.

    The use of vertical sounding balloons for stratospheric photochemistry studies is illustrated by the use of a vertical piloted gas balloon for the search of NO2 diurnal variations. It is shown that the use of montgolfieres (hot air balloons) can enhance the vertical sounding technique. Particular attention is given to a sun-heated montgolfiere and to the more sophisticated infrared montgolfiere that is able to perform three to four vertical excursions per day and to remain aloft for weeks or months.

  4. Determinations of vertical stroke V{sub cb} vertical stroke and vertical stroke V{sub ub} vertical stroke from baryonic Λ{sub b} decays

    Energy Technology Data Exchange (ETDEWEB)

    Hsiao, Y.K. [Shanxi Normal University, School of Physics and Information Engineering, Linfen (China); National Tsing Hua University, Department of Physics, Hsinchu (China); Geng, C.Q. [Shanxi Normal University, School of Physics and Information Engineering, Linfen (China); National Tsing Hua University, Department of Physics, Hsinchu (China); Hunan Normal University, Synergetic Innovation Center for Quantum Effects and Applications (SICQEA), Changsha (China)

    2017-10-15

    We present the first attempt to extract vertical stroke V{sub cb} vertical stroke from the Λ{sub b} → Λ{sub c}{sup +}l anti ν{sub l} decay without relying on vertical stroke V{sub ub} vertical stroke inputs from the B meson decays. Meanwhile, the hadronic Λ{sub b} → Λ{sub c}M{sub (c)} decays with M = (π{sup -},K{sup -}) and M{sub c} =(D{sup -},D{sup -}{sub s}) measured with high precisions are involved in the extraction. Explicitly, we find that vertical stroke V{sub cb} vertical stroke =(44.6 ± 3.2) x 10{sup -3}, agreeing with the value of (42.11 ± 0.74) x 10{sup -3} from the inclusive B → X{sub c}l anti ν{sub l} decays. Furthermore, based on the most recent ratio of vertical stroke V{sub ub} vertical stroke / vertical stroke V{sub cb} vertical stroke from the exclusive modes, we obtain vertical stroke V{sub ub} vertical stroke = (4.3 ± 0.4) x 10{sup -3}, which is close to the value of (4.49 ± 0.24) x 10{sup -3} from the inclusive B → X{sub u}l anti ν{sub l} decays. We conclude that our determinations of vertical stroke V{sub cb} vertical stroke and vertical stroke V{sub ub} vertical stroke favor the corresponding inclusive extractions in the B decays. (orig.)

  5. Geometric effects of 90-degree vertical elbows on local two-phase flow parameters

    International Nuclear Information System (INIS)

    Yadav, M.; Worosz, T.; Kim, S.

    2011-01-01

    This study presents the geometric effects of 90-degree vertical elbows on the development of the local two-phase flow parameters. A multi-sensor conductivity probe is used to measure local two-phase flow parameters. It is found that immediately downstream of the vertical-upward elbow, the bubbles have a bimodal distribution along the horizontal radius of the pipe cross-section causing a dual-peak in the profiles of local void fraction and local interfacial area concentration. Immediately downstream of the vertical-downward elbow it is observed that the bubbles tend to migrate towards the inside of the elbow's curvature. The axial transport of void fraction and interfacial area concentration indicates that the elbows promote bubble disintegration. Preliminary predictions are obtained from group-one interfacial area transport equation (IATE) model for vertical-upward and vertical-downward two-phase flow. (author)

  6. Functionalization of vertically aligned carbon nanotubes.

    Science.gov (United States)

    Van Hooijdonk, Eloise; Bittencourt, Carla; Snyders, Rony; Colomer, Jean-François

    2013-01-01

    This review focuses and summarizes recent studies on the functionalization of carbon nanotubes oriented perpendicularly to their substrate, so-called vertically aligned carbon nanotubes (VA-CNTs). The intrinsic properties of individual nanotubes make the VA-CNTs ideal candidates for integration in a wide range of devices, and many potential applications have been envisaged. These applications can benefit from the unidirectional alignment of the nanotubes, the large surface area, the high carbon purity, the outstanding electrical conductivity, and the uniformly long length. However, practical uses of VA-CNTs are limited by their surface characteristics, which must be often modified in order to meet the specificity of each particular application. The proposed approaches are based on the chemical modifications of the surface by functionalization (grafting of functional chemical groups, decoration with metal particles or wrapping of polymers) to bring new properties or to improve the interactions between the VA-CNTs and their environment while maintaining the alignment of CNTs.

  7. Metal Oxide Vertical Graphene Hybrid Supercapacitors

    Science.gov (United States)

    Meyyappan, Meyya (Inventor)

    2018-01-01

    A metal oxide vertical graphene hybrid supercapacitor is provided. The supercapacitor includes a pair of collectors facing each other, and vertical graphene electrode material grown directly on each of the pair of collectors without catalyst or binders. A separator may separate the vertical graphene electrode materials.

  8. Assessment of Open-Angle Glaucoma Peripapillary and Macular Choroidal Thickness Using Swept-Source Optical Coherence Tomography (SS-OCT.

    Directory of Open Access Journals (Sweden)

    Yong Ju Song

    Full Text Available To compare peripapillary and macular choroidal thickness (PCT and MCT between open-angle glaucoma (OAG and normal controls using swept-source optical coherence tomography (SS-OCT, and to evaluate global and localized relationships between choroidal thickness and various factors in OAG, also using SS-OCT.In this cross-sectional comparative study, 134 OAG patients and 73 normal controls were examined. PCT (global, 12 clock-hour sectors, MCT (global, six sectors were measured by SS-OCT. The difference in choroidal thickness between the OAG patients and the normal controls was analyzed. The relationships between choroidal thickness and various factors including age, sex, spherical equivalent (SE, axial length (AXL, central corneal thickness (CCT, intraocular pressure (IOP, peripapillary retinal nerve fiber layer thickness (pRNFLT, visual field mean deviation (MD, ganglion cell-inner plexiform layer thickness (GCIPLT, and disc area were analyzed by univariate and multivariate linear regression. Global and regional analyses were performed in 12 segments of the peripapillary circle and in six sectors of the macula.There were significant differences in global PCT and MCT between the OAG patients and the normal controls (115.22±41.17 vs. 138.89±44.70, P<0.001, (184.36±57.15 vs. 209.25±61.11, P = 0.004. The difference in global PCT remained, both after adjusting for age, AXL (117.08±3.45 vs. 135.47±4.70, P = 0.002 and also after adjusting for age, AXL, disc area (117.46±3.46 vs. 135.67±4.67, P = 0.002. But the difference in global MCT did not remain after adjusting for age, AXL, SE (188.18±4.46 vs. 202.25±6.08, P = 0.066. PCT showed significant differences between the groups in all of the 12 clock-hour sectors. These differences remained after adjusting for age, AXL and for age, AXL, disc area, with the exception of the 10 o'clock (o/c sector. MCT in six sectors showed differences between the two groups, but they did not remain after adjusting

  9. Crystalline beams: The vertical zigzag

    International Nuclear Information System (INIS)

    Haffmans, A.F.; Maletic, D.; Ruggiero, A.G.

    1994-01-01

    This note is the continuation of our comprehensive investigation of Crystalline Beams. After having determined the equations of motion and the conditions for the formation of the simplest configuration, i.e. the string, we study the possibility of storing an intense beam of charged particles in a storage ring where they form a vertical zigzag. We define the equilibrium configuration, and examine the confinement conditions. Subsequently, we derive the transfer matrix for motion through various elements of the storage ring. Finally we investigate the stability conditions for such a beam

  10. Vertices in the abelized picture

    International Nuclear Information System (INIS)

    Embacher, F.

    1990-01-01

    Covariant vertices of open bosonic string theory are transformed to the abelized picture. The way the pure transverse (light-cone gauge) vertex is contained therein is exhibited explicitly. The formalism shows in a quite transparent way that all further content of a covariant vertex is of gauge type. By applying the transverse projection operator in the abelized picture, an algebraic condition whether a set of Neumann coefficients define a vertex for string theory is obtained. A speculation concerning field redefinitions in string field theory is added. (Author) 33 refs

  11. Vertical integration of medical education: Riverland experience, South Australia.

    Science.gov (United States)

    Rosenthal, D R; Worley, P S; Mugford, B; Stagg, P

    2004-01-01

    Vertical integration of medical education is currently a prominent international topic, resulting from recent strategic initiatives to improve medical education and service delivery in areas of poorly met medical need. In this article, vertical integration of medical education is defined as 'a grouping of curricular content and delivery mechanisms, traversing the traditional boundaries of undergraduate, postgraduate and continuing medical education, with the intent of enhancing the transfer of knowledge and skills between those involved in the learning-teaching process'. Educators closely involved with vertically integrated teaching in the Riverland of South Australia present an analytical description of the educational dynamics of this system. From this analysis, five elements are identified which underpin the process of successful vertical integration: (1) raised educational stakes; (2) local ownership; (3) broad university role; (4) longer attachments; and (5) shared workforce vision. Given the benefits to the Riverland medical education programs described in this paper, it is not surprising that vertical integration of medical education is a popular goal in many rural regions throughout the world. Although different contexts will result in different functional arrangements, it could be argued that the five principles outlined in this article can be applied in any region.

  12. Determination of the quark coupling strength vertical bar V-ub vertical bar using baryonic decays

    NARCIS (Netherlands)

    Aaij, R.; Adeva, B.; Adinolfi, M.; Older, A. A.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Cartelle, P. Alvarez; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Gutierrez, O. Aquines; Archilli, F.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Bachmann, S.; Back, J. J.; Badalov, A.; Baesso, C.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Batozskaya, V.; Battista, V.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Bel, L. J.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Onderwater, C. J. G.; Pellegrino, A.; Tolk, S.

    In the Standard Model of particle physics, the strength of the couplings of the b quark to the u and c quarks, vertical bar V-ub vertical bar and vertical bar V-ub vertical bar, are governed by the coupling of the quarks to the Higgs boson. Using data from the LHCb experiment at the Large Hadron

  13. Vertically stacked nanocellulose tactile sensor.

    Science.gov (United States)

    Jung, Minhyun; Kim, Kyungkwan; Kim, Bumjin; Lee, Kwang-Jae; Kang, Jae-Wook; Jeon, Sanghun

    2017-11-16

    Paper-based electronic devices are attracting considerable attention, because the paper platform has unique attributes such as flexibility and eco-friendliness. Here we report on what is claimed to be the firstly fully integrated vertically-stacked nanocellulose-based tactile sensor, which is capable of simultaneously sensing temperature and pressure. The pressure and temperature sensors are operated using different principles and are stacked vertically, thereby minimizing the interference effect. For the pressure sensor, which utilizes the piezoresistance principle under pressure, the conducting electrode was inkjet printed on the TEMPO-oxidized-nanocellulose patterned with micro-sized pyramids, and the counter electrode was placed on the nanocellulose film. The pressure sensor has a high sensitivity over a wide range (500 Pa-3 kPa) and a high durability of 10 4 loading/unloading cycles. The temperature sensor combines various materials such as poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), silver nanoparticles (AgNPs) and carbon nanotubes (CNTs) to form a thermocouple on the upper nanocellulose layer. The thermoelectric-based temperature sensors generate a thermoelectric voltage output of 1.7 mV for a temperature difference of 125 K. Our 5 × 5 tactile sensor arrays show a fast response, negligible interference, and durable sensing performance.

  14. In vivo crystalline lens measurements with novel swept-source optical coherent tomography: an investigation on variability of measurement

    Science.gov (United States)

    Shoji, Takuhei; Kato, Naoko; Ishikawa, Sho; Ibuki, Hisashi; Yamada, Norihiro; Kimura, Itaru; Shinoda, Kei

    2017-01-01

    Objective To evaluate the reproducibility of in vivo crystalline lens measurements obtained by novel commercially available swept-source (SS) optical coherence tomography (OCT) specifically designed for anterior segment imaging. Methods and analysis One eye from each of 30 healthy subjects was randomly selected using the CASIA2 (Tomey, Nagoya, Japan) in two separate visits within a week. Each eye was imaged twice. After image scanning, the anterior and posterior lens curvatures and lens thickness were calculated automatically by the CASIA2 built-in program at 0 dioptre (D) (static), −1 D, −3 D and −5 D accommodative stress. The intraobserver and intervisit reproducibility coefficient (RC) and intraclass correlation coefficient (ICC) were calculated. Results The intraobserver and intervisit RCs ranged from 0.824 to 1.254 mm and 0.789 to 0.911 mm for anterior lens curvature, from 0.276 to 0.299 mm and 0.221 to 0.270 mm for posterior lens curvature and from 0.065 to 0.094 mm and 0.054 to 0.132 mm for lens thickness, respectively. The intraobserver and intervisit ICCs ranged from 0.831 to 0.865 and 0.828 to 0.914 for anterior lens curvature, from 0.832 to 0.898 and 0.840 to 0.933 for posterior lens curvature and from 0.980 to 0.992 and 0.942 to 0.995 for lens thickness. High ICC values were observed for each measurement regardless of accommodative stress. RCs in younger subjects tended to be larger than those in older subjects. Conclusions This novel anterior segment SS-OCT instrument produced reliable in vivo crystalline lens measurement with good repeatability and reproducibility regardless of accommodation stress. PMID:29354706

  15. The Effect of Backward-Facing Step Height on Instability Growth and Breakdown in Swept Wing Boundary-Layer Transition

    Science.gov (United States)

    Eppink, Jenna L.; Wlezien, Richard W.; King, Rudolph A.; Choudhari, Meelan

    2015-01-01

    A low-speed experiment was performed on a swept at plate model with an imposed pressure gradient to determine the effect of a backward-facing step on transition in a stationary-cross flow dominated flow. Detailed hot-wire boundary-layer measurements were performed for three backward-facing step heights of approximately 36, 45, and 49% of the boundary-layer thickness at the step. These step heights correspond to a subcritical, nearly-critical, and critical case. Three leading-edge roughness configurations were tested to determine the effect of stationary-cross flow amplitude on transition. The step caused a local increase in amplitude of the stationary cross flow for the two larger step height cases, but farther downstream the amplitude decreased and remained below the baseline amplitude. The smallest step caused a slight local decrease in amplitude of the primary stationary cross flow mode, but the amplitude collapsed back to the baseline case far downstream of the step. The effect of the step on the amplitude of the primary cross flow mode increased with step height, however, the stationary cross flow amplitudes remained low and thus, stationary cross flow was not solely responsible for transition. Unsteady disturbances were present downstream of the step for all three step heights, and the amplitudes increased with increasing step height. The only exception is that the lower frequency (traveling crossflow-like) disturbance was not present in the lowest step height case. Positive and negative spikes in instantaneous velocity began to occur for the two larger step height cases and then grew in number and amplitude downstream of reattachment, eventually leading to transition. The number and amplitude of spikes varied depending on the step height and cross flow amplitude. Despite the low amplitude of the disturbances in the intermediate step height case, breakdown began to occur intermittently and the flow underwent a long transition region.

  16. Comparison of choroidal thickness measurements between spectral-domain OCT and swept-source OCT in normal and diseased eyes

    Directory of Open Access Journals (Sweden)

    Zafar S

    2016-11-01

    Full Text Available Sidra Zafar,1 MA Rehman Siddiqui,2,3 Rida Shahzad1 1Medical College, Aga Khan University Hospital, 2Department of Ophthalmology, Shahzad Eye Hospital, 3South City Hospital, Karachi, Pakistan Purpose: Sub-foveal choroidal thickness (SFCT is affected in many ocular diseases. The aim of this study was to compare SFCT measurements between Topcon 3D 2000 spectral-domain optical coherence tomography (SD-OCT and Topcon swept-source OCT (SS-OCT, with different laser wavelengths, in normal and diseased populations. Materials and methods: This was a prospective, cross-sectional, noninterventional study including 27 normal volunteers and 27 participants with retinal disease. OCT scans were performed sequentially and under standardized conditions using both SD-OCT and SS-OCT. The OCT scans were evaluated by two independent graders. Paired t-tests and intraclass correlation coefficients (ICCs were used to assess the statistically significant difference between SFCT measurements as measured by the two devices. Results: Mean SFCT measurements for all 54 participants were 264.9±103.1 µm using SD-OCT (range: 47–470 µm and 278.5±110.5 µm using SS-OCT (range: 56–502 µm, with an inter-device ICC of 0.850. Greater variability was noted in the diseased eyes. Inter-device ICCs were 0.870 (95% CI; 0.760–0.924 and 0.840 (95% CI; 0.654–0.930 for normal and diseased eyes, respectively. However, the difference was not statistically significant (P=0.132. Conclusion: Both machines reliably measure SFCT. Larger studies are needed to confirm these findings. Keywords: choroidal imaging, diseased, normal, SD-OCT, SS-OCT

  17. Comparison of Keratometry Obtained by a Swept Source OCT-Based Biometer with a Standard Optical Biometer and Scheimpflug Imaging.

    Science.gov (United States)

    Asena, Leyla; Akman, Ahmet; Güngör, Sirel Gür; Dursun Altınörs, Dilek

    2018-04-09

    To assess agreement of a swept source-optical coherence tomography (SS-OCT) based Biometer with a standard IOLMaster device and Scheimpflug Imaging (SI) to acquire keratometric measurements in cataract patients. In this prospective comparative study, 101 eyes of 101 cataract surgery candidates, aged 24-81 years, were sequentially examined using three devices. Keratometry values at the flat (K1) and steep (K2) axis, mean corneal power (Km) and magnitude of corneal astigmatism as well as J0 and J45 vectoral components of astigmatism obtained with the SS-OCT based biometer (IOLMaster 700) were compared with those obtained with the IOLMaster 500 and SI. The agreement between measurements was evaluated by the Bland-Altman method, intraclass correlation coefficients (ICCs) and repeated-measures analysis of variance. Mean K1 values from the three devices were similar (p = 0.09). Mean K2 and Km values of IOLMaster 700 were higher than SI and lower than IOLMaster 500 (p = 0.04 for K2 and p = 0.02 for Km). There was a strong correlation between K1, K2, Km and magnitude of astigmatism obtained with all devices (r ≥ 0.80 and p devices was excellent for keratometric measurements. Mean K2, Km and astigmatism measurements from IOLMaster 700 were lower than IOLMaster 500 and higher than SI. However, the differences were quite small and are not expected to affect the final IOL power.

  18. 典型电器工业区河涌沉积物中的多溴联苯醚空间和垂直分布%Horizontal and Vertical Distribution of Polybrominated Diphenyl Ethers(PBDEs) in River Sediment from a Typical Electrical Equipment Industrial Area

    Institute of Scientific and Technical Information of China (English)

    邱孟德; 邓代永; 余乐洹; 孙国萍; 麦碧娴; 许玫英

    2012-01-01

    对珠江三角洲佛山市顺德区容桂镇电器工业区河涌沉积物多溴联苯醚(PBDEs)的含量进行了空间和垂直分布研究.选择该镇中心城区内河涌作为研究河道,根据河涌水流情况选取8个采样点采集沉积物样品.所有样品中均检出PBDEs.各监测点的PBDEs总含量变化范围为62~349 ng.g-1(平均为178 ng.g-1),各采样点的浓度差异较大.其中,十溴联苯醚含量为56~337 ng.g-1(平均为171 ng.g-1),占PBDEs总含量的90%~99%(平均95%).所检测到的部分同系物(如BDE-196、197和203)可能是BDE-209的降解产物.PBDEs的垂直分布模式显示,0~10 cm层面样品的PBDEs浓度为147 ng.g-1,30~40 cm层面样品的PBDEs浓度为260 ng.g-1,PBDEs在沉积物中的丰度随垂直深度的增加而增加.12种同系物在采自各个深度层样品中的比例基本相同,由十溴工业品来源的BDE-209、208、207和206占总PBDEs的94%,而五溴和八溴所占比例较低.由此可见,该地区普遍存在PBDEs污染,其中十溴联苯醚是最主要污染物,这可能与十溴工业品是电器工业主要使用的阻燃材料相关.%Polybrominated diphenyl ethers(PBDEs) were determined in sediment collected from a river in a typical electrical equipment industrial area,Ronggui,Foshan.Eight samples were collected from river sediment.The results indicated that PBDEs were presented in all samples.Spatial trends showed that the concentrations of PBDEs in all sediment samples were ranged from 62 ng·g-1 to 349 ng·g-1,with an average of 178 ng·g-1.The predominant congener was BDE-209(90%-99%),which ranged from 56-337 ng·g-1,with an average of 171 ng·g-1.Some of congeners such as BDE-196,197 and 203 may be were the degradation product of BDE-209.Vertically,the concentrations of PBDEs were increased with the depth,whereas the concentrations were 147 ng·g-1 in layer 0-10 cm and 260 ng·g-1 in layer 30-40 cm,respectively.Distribution profile of PBDEs in

  19. [EEG-markers of vertical postural organization in healthy persons].

    Science.gov (United States)

    Zhavoronkova, L A; Zharikova, A V; Kushnir, E M; Mikhalkova, A A

    2012-01-01

    In 10 healthy persons (22.8 +/- 0.67 years) spectral-coherence parameters of EEG were analyzed in different steps of verticalizations--from gorizontal position to seat and stand one. Maximal changes of all EEG parameters were observed in state with absence of visual control. We observed an increase of power for fast spectral bands of EEG (beta- and gamma-bands) in all conditions and additional increase of these EEG parameters was observed at situation of complication of conditions of vertical pose supporting. Results of EEG coherent analysis in conditions of human verticalization showed specific increase of coherence for the majority of rhythm ranges in the right hemisphere especially in the central-frontal and in occipital-parietal areas and for interhemispheric pairs for these leads. This fact can reflect participation of cortical as well as subcortical structures in these processes. In conditions of complicate conditions of vertical pose supporting the additional increase of EEG coherence in fast bands (beta-rhythm) was observed at the frontal areas. This fact can testify about increasing of executive functions in this conditions.

  20. Novel vertical silicon photodiodes based on salicided polysilicon trenched contacts

    International Nuclear Information System (INIS)

    Kaminski, Yelena; Shauly, Eitan; Paz, Yaron

    2015-01-01

    The classical concept of silicon photodiodes comprises of a planar design characterized by heavily doped emitters. Such geometry has low collection efficiency of the photons absorbed close to the surface. An alternative, promising, approach is to use a vertical design. Nevertheless, realization of such design is technologically challenged, hence hardly explored. Herein, a novel type of silicon photodiodes, based on salicided polysilicon trenched contacts, is presented. These contacts can be prepared up to 10 μm in depth, without showing any leakage current associated with the increase in the contact area. Consequently, the trenched photodiodes revealed better performance than no-trench photodiodes. A simple two dimensional model was developed, allowing to estimate the conditions under which a vertical design has the potential to have better performance than that of a planar design. At large, the deeper the trench is, the better is the vertical design relative to the planar (up to 10 μm for silicon). The vertical design is more advantageous for materials characterized by short diffusion lengths of the carriers. Salicided polysilicon trenched contacts open new opportunities for the design of solar cells and image sensors. For example, these contacts may passivate high contact area buried contacts, by virtue of the conformity of polysilicon interlayer, thus lowering the via resistance induced recombination enhancement effect

  1. Novel vertical silicon photodiodes based on salicided polysilicon trenched contacts

    Energy Technology Data Exchange (ETDEWEB)

    Kaminski, Yelena [Department of Chemical Engineering, Technion, Haifa (Israel); TowerJazz Ltd. Migdal Haemek (Israel); Shauly, Eitan [TowerJazz Ltd. Migdal Haemek (Israel); Paz, Yaron, E-mail: paz@tx.technion.ac.il [Department of Chemical Engineering, Technion, Haifa (Israel)

    2015-12-07

    The classical concept of silicon photodiodes comprises of a planar design characterized by heavily doped emitters. Such geometry has low collection efficiency of the photons absorbed close to the surface. An alternative, promising, approach is to use a vertical design. Nevertheless, realization of such design is technologically challenged, hence hardly explored. Herein, a novel type of silicon photodiodes, based on salicided polysilicon trenched contacts, is presented. These contacts can be prepared up to 10 μm in depth, without showing any leakage current associated with the increase in the contact area. Consequently, the trenched photodiodes revealed better performance than no-trench photodiodes. A simple two dimensional model was developed, allowing to estimate the conditions under which a vertical design has the potential to have better performance than that of a planar design. At large, the deeper the trench is, the better is the vertical design relative to the planar (up to 10 μm for silicon). The vertical design is more advantageous for materials characterized by short diffusion lengths of the carriers. Salicided polysilicon trenched contacts open new opportunities for the design of solar cells and image sensors. For example, these contacts may passivate high contact area buried contacts, by virtue of the conformity of polysilicon interlayer, thus lowering the via resistance induced recombination enhancement effect.

  2. Development of Vertical Cable Seismic System (2)

    Science.gov (United States)

    Asakawa, E.; Murakami, F.; Tsukahara, H.; Ishikawa, K.

    2012-12-01

    The vertical cable seismic is one of the reflection seismic methods. It uses hydrophone arrays vertically moored from the seafloor to record acoustic waves generated by surface, deep-towed or ocean bottom sources. Analyzing the reflections from the sub-seabed, we could look into the subsurface structure. This type of survey is generally called VCS (Vertical Cable Seismic). Because VCS is an efficient high-resolution 3D seismic survey method for a spatially-bounded area, we proposed the method for the hydrothermal deposit survey tool development program that the Ministry of Education, Culture, Sports, Science and Technology (MEXT) started in 2009. We are now developing a VCS system, including not only data acquisition hardware but data processing and analysis technique. Our first experiment of VCS surveys has been carried out in Lake Biwa, JAPAN in November 2009 for a feasibility study. Prestack depth migration is applied to the 3D VCS data to obtain a high quality 3D depth volume. Based on the results from the feasibility study, we have developed two autonomous recording VCS systems. After we carried out a trial experiment in the actual ocean at a water depth of about 400m and we carried out the second VCS survey at Iheya Knoll with a deep-towed source. In this survey, we could establish the procedures for the deployment/recovery of the system and could examine the locations and the fluctuations of the vertical cables at a water depth of around 1000m. The acquired VCS data clearly shows the reflections from the sub-seafloor. Through the experiment, we could confirm that our VCS system works well even in the severe circumstances around the locations of seafloor hydrothermal deposits. We have carried out two field surveys in 2011. One is a 3D survey with a boomer for a high-resolution surface source and the other one for an actual field survey in the Izena Cauldron an active hydrothermal area in the Okinawa Trough. Through these surveys, we have confirmed that the

  3. Capillary holdup between vertical spheres

    Directory of Open Access Journals (Sweden)

    S. Zeinali Heris

    2009-12-01

    Full Text Available The maximum volume of liquid bridge left between two vertically mounted spherical particles has been theoretically determined and experimentally measured. As the gravitational effect has not been neglected in the theoretical model, the liquid interface profile is nonsymmetrical around the X-axis. Symmetry in the interface profile only occurs when either the particle size ratio or the gravitational force becomes zero. In this paper, some equations are derived as a function of the spheres' sizes, gap width, liquid density, surface tension and body force (gravity/centrifugal to estimate the maximum amount of liquid that can be held between the two solid spheres. Then a comparison is made between the result based on these equations and several experimental results.

  4. Vertically Integrated Edgeless Photon Imaging Camera

    Energy Technology Data Exchange (ETDEWEB)

    Fahim, Farah [Fermilab; Deptuch, Grzegorz [Fermilab; Shenai, Alpana [Fermilab; Maj, Piotr [AGH-UST, Cracow; Kmon, Piotr [AGH-UST, Cracow; Grybos, Pawel [AGH-UST, Cracow; Szczygiel, Robert [AGH-UST, Cracow; Siddons, D. Peter [Brookhaven; Rumaiz, Abdul [Brookhaven; Kuczewski, Anthony [Brookhaven; Mead, Joseph [Brookhaven; Bradford, Rebecca [Argonne; Weizeorick, John [Argonne

    2017-01-01

    The Vertically Integrated Photon Imaging Chip - Large, (VIPIC-L), is a large area, small pixel (65μm), 3D integrated, photon counting ASIC with zero-suppressed or full frame dead-time-less data readout. It features data throughput of 14.4 Gbps per chip with a full frame readout speed of 56kframes/s in the imaging mode. VIPIC-L contain 192 x 192 pixel array and the total size of the chip is 1.248cm x 1.248cm with only a 5μm periphery. It contains about 120M transistors. A 1.3M pixel camera module will be developed by arranging a 6 x 6 array of 3D VIPIC-L’s bonded to a large area silicon sensor on the analog side and to a readout board on the digital side. The readout board hosts a bank of FPGA’s, one per VIPIC-L to allow processing of up to 0.7 Tbps of raw data produced by the camera.

  5. Simultaneous multi-laser, multi-species trace-level sensing of gas mixtures by rapidly swept continuous-wave cavity-ringdown spectroscopy.

    Science.gov (United States)

    He, Yabai; Kan, Ruifeng; Englich, Florian V; Liu, Wenqing; Orr, Brian J

    2010-09-13

    The greenhouse-gas molecules CO(2), CH(4), and H(2)O are detected in air within a few ms by a novel cavity-ringdown laser-absorption spectroscopy technique using a rapidly swept optical cavity and multi-wavelength coherent radiation from a set of pre-tuned near-infrared diode lasers. The performance of various types of tunable diode laser, on which this technique depends, is evaluated. Our instrument is both sensitive and compact, as needed for reliable environmental monitoring with high absolute accuracy to detect trace concentrations of greenhouse gases in outdoor air.

  6. Estimating Vertical Stress on Soil Subjected to Vehicular Loading

    Science.gov (United States)

    2009-02-01

    specified surface area of the tire . The silt and sand samples were both estimated to be 23.7-in. thick over a base of much harder soil. The pressures...study in which highway tread tires were used as opposed to the all-terrain tread currently on the vehicle. If the pressure pads are functioning...Vertical force versus time (front right CIV tire )....................................................................... 14 Tables Table 1. Testing

  7. Low-Reynolds Number Aerodynamics of an 8.9 Percent Scale Semispan Swept Wing for Assessment of Icing Effects

    Science.gov (United States)

    Broeren, Andy P.; Woodard, Brian S.; Diebold, Jeffrey M.; Moens, Frederic

    2017-01-01

    Aerodynamic assessment of icing effects on swept wings is an important component of a larger effort to improve three-dimensional icing simulation capabilities. An understanding of ice-shape geometric fidelity and Reynolds and Mach number effects on the iced-wing aerodynamics is needed to guide the development and validation of ice-accretion simulation tools. To this end, wind-tunnel testing and computational flow simulations were carried out for an 8.9 percent-scale semispan wing based upon the Common Research Model airplane configuration. The wind-tunnel testing was conducted at the Wichita State University 7 by 10 ft Beech wind tunnel from Reynolds numbers of 0.8×10(exp 6) to 2.4×10(exp 6) and corresponding Mach numbers of 0.09 to 0.27. This paper presents the results of initial studies investigating the model mounting configuration, clean-wing aerodynamics and effects of artificial ice roughness. Four different model mounting configurations were considered and a circular splitter plate combined with a streamlined shroud was selected as the baseline geometry for the remainder of the experiments and computational simulations. A detailed study of the clean-wing aerodynamics and stall characteristics was made. In all cases, the flow over the outboard sections of the wing separated as the wing stalled with the inboard sections near the root maintaining attached flow. Computational flow simulations were carried out with the ONERA elsA software that solves the compressible, threedimensional RANS equations. The computations were carried out in either fully turbulent mode or with natural transition. Better agreement between the experimental and computational results was obtained when considering computations with free transition compared to turbulent solutions. These results indicate that experimental evolution of the clean wing performance coefficients were due to the effect of three-dimensional transition location and that this must be taken into account for future

  8. Comparison of central corneal thickness with four noncontact devices: An agreement analysis of swept-source technology

    Directory of Open Access Journals (Sweden)

    Erhan Ozyol

    2017-01-01

    Full Text Available Purpose: The purpose of this study was to compare the central corneal thickness (CCT measurements of four noncontact devices in healthy eyes. Materials and Methods: In a sample of 45 healthy controls, CCT was measured using an optical biometer (IOLMaster 700 based on swept-source optical coherence tomography (SS-OCT, high-resolution rotating Scheimpflug camera system (Pentacam HR, spectral-domain OCT (SD-OCT device with an anterior segment module (Spectralis, and noncontact pachymetry (NCP device (Topcon TRK-2P. Agreement among the devices was analyzed using mean differences (i.e., bias and Bland–Altman analysis with 95% limits of agreement (LoA. Results: Mean CCT measurements were 537.5 ± 47.5 μm for SS-OCT optical biometer, 532.3 ± 43.8 μm for Scheimpflug system, 521.3 ± 44.7 μm for SD-OCT device, and 518.0 ± 43.1 μm for NCP (P < 0.001. The SD-OCT device and NCP showed the closest agreement, with a bias of 2.6 μm (95% LoA, −3.6–8.8 μm, whereas the SS-OCT optical biometer and NCP showed the least agreement, with a bias of 18.7 μm (95% LoA, −2.1–39.5 μm. Bias was 16.1 μm (95% LoA, −3.1–35.3 μm for SS-OCT optical biometer and SD-OCT, 5.1 μm (95% LoA, −6.8–17.0 μm for SS-OCT optical biometer and Scheimpflug system, 10.9 μm (95% LoA, −15.1–36.9 μm for SD-OCT device and Scheimpflug system, and 13.6 μm (95% LoA, −5–32.2 μm for Scheimpflug system and NCP. Conclusions: SS-OCT optical biometer overestimates CCT measurements compared to Scheimpflug system, SD-OCT device, and NCP. Given mean differences and range variations in CCT measurements between devices, SS-OCT optical biometer and Scheimpflug system are interchangeable as are SD-OCT and NCP.

  9. Comparison of central corneal thickness with four noncontact devices: An agreement analysis of swept-source technology.

    Science.gov (United States)

    Ozyol, Erhan; Özyol, Pelin

    2017-06-01

    The purpose of this study was to compare the central corneal thickness (CCT) measurements of four noncontact devices in healthy eyes. In a sample of 45 healthy controls, CCT was measured using an optical biometer (IOLMaster 700) based on swept-source optical coherence tomography (SS-OCT), high-resolution rotating Scheimpflug camera system (Pentacam HR), spectral-domain OCT (SD-OCT) device with an anterior segment module (Spectralis), and noncontact pachymetry (NCP) device (Topcon TRK-2P). Agreement among the devices was analyzed using mean differences (i.e., bias) and Bland-Altman analysis with 95% limits of agreement (LoA). Mean CCT measurements were 537.5 ± 47.5 μm for SS-OCT optical biometer, 532.3 ± 43.8 μm for Scheimpflug system, 521.3 ± 44.7 μm for SD-OCT device, and 518.0 ± 43.1 μm for NCP (P < 0.001). The SD-OCT device and NCP showed the closest agreement, with a bias of 2.6 μm (95% LoA, -3.6-8.8 μm), whereas the SS-OCT optical biometer and NCP showed the least agreement, with a bias of 18.7 μm (95% LoA, -2.1-39.5 μm). Bias was 16.1 μm (95% LoA, -3.1-35.3 μm) for SS-OCT optical biometer and SD-OCT, 5.1 μm (95% LoA, -6.8-17.0 μm) for SS-OCT optical biometer and Scheimpflug system, 10.9 μm (95% LoA, -15.1-36.9 μm) for SD-OCT device and Scheimpflug system, and 13.6 μm (95% LoA, -5-32.2 μm) for Scheimpflug system and NCP. SS-OCT optical biometer overestimates CCT measurements compared to Scheimpflug system, SD-OCT device, and NCP. Given mean differences and range variations in CCT measurements between devices, SS-OCT optical biometer and Scheimpflug system are interchangeable as are SD-OCT and NCP.

  10. Vertical Cable Seismic Survey for SMS exploration

    Science.gov (United States)

    Asakawa, Eiichi; Murakami, Fumitoshi; Tsukahara, Hotoshi; Mizohata, Shigeharu

    2014-05-01

    The Vertical Cable Seismic (VCS) survey is one of the reflection seismic methods. It uses hydrophone arrays vertically moored from the seafloor to record acoustic waves generated by sea-surface, deep-towed or ocean bottom sources. Analyzing the reflections from the sub-seabed, we could look into the subsurface structure. Because the VCS is an efficient high-resolution 3D seismic survey method for a spatially-bounded area, we proposed it for the SMS survey tool development program that the Ministry of Education, Culture, Sports, Science and Technology (MEXT) started in 2009. We have been developing the VCS survey system, including not only data acquisition hardware but data processing and analysis technique. We carried out several VCS surveys combining with surface towed source, deep towed source and ocean bottom source. The water depths of these surveys are from 100m up to 2100 m. Through these experiments, our VCS data acquisition system has been also completed. But the data processing techniques are still on the way. One of the most critical issues is the positioning in the water. The uncertainty in the positions of the source and of the hydrophones in water degraded the quality of subsurface image. GPS navigation system is available on sea surface, but in case of deep-towed source or ocean bottom source, the accuracy of shot position with SSBL/USBL is not sufficient for the very high-resolution imaging. We have developed a new approach to determine the positions in water using the travel time data from the source to VCS hydrophones. In 2013, we have carried out the second VCS survey using the surface-towed high-voltage sparker and ocean bottom source in the Izena Cauldron, which is one of the most promising SMS areas around Japan. The positions of ocean bottom source estimated by this method are consistent with the VCS field records. The VCS data with the sparker have been processed with 3D PSTM. It gives the very high resolution 3D volume deeper than two

  11. Vertical grid of retrieved atmospheric profiles

    International Nuclear Information System (INIS)

    Ceccherini, Simone; Carli, Bruno; Raspollini, Piera

    2016-01-01

    The choice of the vertical grid of atmospheric profiles retrieved from remote sensing observations is discussed considering the two cases of profiles used to represent the results of individual measurements and of profiles used for subsequent data fusion applications. An ozone measurement of the MIPAS instrument is used to assess, for different vertical grids, the quality of the retrieved profiles in terms of profile values, retrieval errors, vertical resolutions and number of degrees of freedom. In the case of individual retrievals no evident advantage is obtained with the use of a grid finer than the one with a reduced number of grid points, which are optimized according to the information content of the observations. Nevertheless, this instrument dependent vertical grid, which seems to extract all the available information, provides very poor results when used for data fusion applications. A loss of about a quarter of the degrees of freedom is observed when the data fusion is made using the instrument dependent vertical grid relative to the data fusion made using a vertical grid optimized for the data fusion product. This result is explained by the analysis of the eigenvalues of the Fisher information matrix and leads to the conclusion that different vertical grids must be adopted when data fusion is the expected application. - Highlights: • Data fusion application is taken into account for the choice of the vertical grid. • The study is performed using ozone profiles retrieved from MIPAS measurements. • A very fine vertical grid is not needed for the analysis of a single instrument. • The instrument dependent vertical grid is not the best choice for data fusion. • A data fusion dependent vertical grid must be used for profiles that will be fused.

  12. Vertical and horizontal access configurations

    International Nuclear Information System (INIS)

    Spampinato, P.T.

    1987-01-01

    A number of configuration features and maintenance operations are influenced by the choice of whether a design is based on vertical or horizontal access for replacing reactor components. The features which are impacted most include the first wall/blanket segmentation, the poloidal field coil locations, the toroidal field coil number and size, access port size for in-vessel components, and facilities. Since either configuration can be made to work, the choice between the two is not clear cut because both have certain advantages. It is apparent that there are large cost benefits in the poloidal field coil system for ideal coil locations for high elongation plasmas and marginal savings for the INTOR case. If we assume that a new tokamak design will require a higher plasma elongation, the recommendation is to arrange the poloidal field coils in a cost-effective manner while providing reasonable midplane access for heating interfaces and test modules. If a new design study is not based on a high elongation plasma, it still appears prudent to consider this approach so that in-vessel maintenance can be accomplished without moving very massive structures such as the bulk shield. 10 refs., 29 figs., 3 tabs

  13. The Ames Vertical Gun Range

    Science.gov (United States)

    Karcz, J. S.; Bowling, D.; Cornelison, C.; Parrish, A.; Perez, A.; Raiche, G.; Wiens, J.-P.

    2016-01-01

    The Ames Vertical Gun Range (AVGR) is a national facility for conducting laboratory- scale investigations of high-speed impact processes. It provides a set of light-gas, powder, and compressed gas guns capable of accelerating projectiles to speeds up to 7 km s(exp -1). The AVGR has a unique capability to vary the angle between the projectile-launch and gravity vectors between 0 and 90 deg. The target resides in a large chamber (diameter approximately 2.5 m) that can be held at vacuum or filled with an experiment-specific atmosphere. The chamber provides a number of viewing ports and feed-throughs for data, power, and fluids. Impacts are observed via high-speed digital cameras along with investigation-specific instrumentation, such as spectrometers. Use of the range is available via grant proposals through any Planetary Science Research Program element of the NASA Research Opportunities in Space and Earth Sciences (ROSES) calls. Exploratory experiments (one to two days) are additionally possible in order to develop a new proposal.

  14. Flooding Mechanism in Vertical Flow

    International Nuclear Information System (INIS)

    Ronny-Dwi Agussulistyo; Indarto

    2000-01-01

    This research was carried out to investigate the mechanism of flooding ina vertical liquid-gas counter current flow, along two meter length of thetube. The tube use both circular and square tube, a cross section of squaretube was made the same as a cross section of circular tube with one inchdiameter tube. The liquid enters the tube, passes through a porous wall inletand a groove inlet in a distributor and it flows downwards through a liquidoutlet in a collector. The gas is being introduced at the bottom of the tube,it flows upwards through nozzle in the collector. The results of researchshowed that the flooding occurs earlier in the circular tube than in thesquare tube, either uses a porous wall inlet or a groove inlet. In the squaretube , onset of the flooding occurs at the top of the tube, in front ofliquid injection, it is related to the formation of a film wave, just belowthe liquid feed. Whereas in the circular tube, onset of the flooding occursfrom the bottom of the tube, at the liquid outlet, it is related to theexpand of the film wave. However, in the circular tube with the groove inlet,for the higher liquid flow rate, onset of the flooding from the top, like inthe square tube. (author)

  15. Wind tower with vertical rotors

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, A

    1978-08-03

    The invention concerns a wind tower with vertical rotors. A characteristic is that the useful output of the rotors is increased by the wind pressure, which is guided to the rotors at the central opening and over the whole height of the structure by duct slots in the inner cells. These duct slots start behind the front nose of the inner cell and lead via the transverse axis of the pillar at an angle into the space between the inner cells and the cell body. This measure appreciably increases the useful output of the rotors, as the rotors do not have to provide any displacement work from their output, but receive additional thrust. The wind pressure pressing from inside the rotor and accelerating from the outside produces a better outflow of the wind from the power plant pillar with only small tendency to turbulence, which appreciably improves the effect of the adjustable turbulence smoothers, which are situated below the rotors over the whole height.

  16. Vertical mixing by Langmuir circulations

    International Nuclear Information System (INIS)

    McWilliams, James C.; Sullivan, Peter P.

    2001-01-01

    Wind and surface wave frequently induce Langmuir circulations (LC) in the upper ocean, and the LC contribute to mixing materials down from the surface. In this paper we analyze large-eddy simulation (LES) cases based on surface-wave-averaged, dynamical equations and show that the effect of the LC is a great increase in the vertical mixing efficiency for both material properties and momentum. We provide new confirmation that the previously proposed K-profile parameterization (KPP) model accurately characterizes the turbulent transport in a weakly convective, wind-driven boundary layer with stable interior stratification. We also propose a modest generalization of KPP for the regime of weakly convective Langmuir turbulence. This makes the KPP turbulent flux profiles match those in the LES case with LC present fairly well, especially so for material properties being transported downwards from the ocean surface. However, some open issues remain about how well the present LES and KPP formulations represent Langmuir turbulence, in part because wave-breaking effects are not yet included. (Author)

  17. Theory of nonaxisymmetric vertical displacement events in tokamaks

    International Nuclear Information System (INIS)

    Fitzpatrick, R.

    2011-01-01

    A semi-analytic sharp-boundary model of a nonaxisymmetric vertical displacement event (VDE) in a large aspect-ratio, high-beta (i.e. β ∼ ε), vertically elongated tokamak plasma is developed. The model is used to simulate nonaxisymmetric VDEs with a wide range of different plasma equilibrium and vacuum vessel parameters. These simulations yield poloidal halo current fractions and toroidal peaking factors whose magnitudes are similar to those seen in experiments, and also reproduce the characteristic inverse scaling between the halo current fraction and the toroidal peaking factor. Moreover, the peak poloidal halo current density in the vacuum vessel is found to correlate strongly with the reciprocal of the minimum edge safety factor attained during the VDE. In addition, under certain circumstances, the ratio of the net sideways force acting on the vacuum vessel to the net vertical force is observed to approach unity. Finally, the peak vertical force per unit area acting on the vessel is found to have a strong correlation with the equilibrium toroidal plasma current at the start of the VDE, but is also found to increase with increasing vacuum vessel resistivity relative to the scrape-off layer plasma.

  18. A preliminary investigation of vertical crustal movements in the United Kingdom in the context of subsurface nuclear waste isolation for the Department of the Environment

    International Nuclear Information System (INIS)

    1981-03-01

    The report falls under the headings: vertical crustal movements - a manifestation of intraplate geological processes (reports of vertical crustal movements observed by geodetic levelling in intraplate environments; vertical crustal movements and the geological record; possible causes of vertical crustal movements); an investigation of recent crustal movements in a test area of the United Kingdom by comparison of geodetic levelling records; vertical crustal movements and the isolation of nuclear waste in intraplate geological systems (conventional methods of site appraisal - a perspective of geological hazard assessment; the role of vertical crustal movements as a tool for rationalisation of hazard assessment, site selection and the assessment of future geological change); research options. (U.K.)

  19. The green building envelope : Vertical greening

    NARCIS (Netherlands)

    Ottelé, M.

    2011-01-01

    Planting on roofs and façades is one of the most innovative and fastest developing fields of green technologies with respect to the built environment and horticulture. This thesis is focused on vertical greening of structures and to the multi-scale benefits of vegetation. Vertical green can improve

  20. Safety Aspects for Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, H. F.; Christiani, E.

    1996-01-01

    In this appendix some safety aspects in relation to vertical wall breakwaters are discussed. Breakwater structures such as vertical wall breakwaters are used under quite different conditions. The expected lifetime can be from 5 years (interim structure) to 100 years (permanent structure) and the ...

  1. Updated Vertical Extent of Collision Damage

    DEFF Research Database (Denmark)

    Tagg, R.; Bartzis, P.; Papanikolaou, P.

    2002-01-01

    The probabilistic distribution of the vertical extent of collision damage is an important and somewhat controversial component of the proposed IMO harmonized damage stability regulations for cargo and passenger ships. The only pre-existing vertical distribution, currently used in the international...

  2. Plasmon Modes of Vertically Aligned Superlattices

    DEFF Research Database (Denmark)

    Filonenko, Konstantin; Duggen, Lars; Willatzen, Morten

    2017-01-01

    By using the Finite Element Method we visualize the modes of vertically aligned superlattice composed of gold and dielectric nanocylinders and investigate the emitter-plasmon interaction in approximation of weak coupling. We find that truncated vertically aligned superlattice can function...

  3. The strategic value of partial vertical integration

    OpenAIRE

    Fiocco, Raffaele

    2014-01-01

    We investigate the strategic incentives for partial vertical integration, namely, partial ownership agreements between manufacturers and retailers, when retailers privately know their costs and engage in differentiated good price competition. The partial misalignment between the profit objectives within a partially integrated manufacturer-retailer hierarchy entails a higher retail price than under full integration. This `information vertical effect' translates into an opposite ...

  4. Vertical integration increases opportunities for patient flow.

    Science.gov (United States)

    Radoccia, R A; Benvenuto, J A; Blancett, L

    1991-08-01

    New sources of patients will become more and more important in the next decade as hospitals continue to feel the squeeze of a competitive marketplace. Vertical integration, a distribution tool used in other industries, will be a significant tool for health care administrators. In the following article, the authors explain the vertical integration model that shows promise for other institutions.

  5. Vertical integration from the large Hilbert space

    Science.gov (United States)

    Erler, Theodore; Konopka, Sebastian

    2017-12-01

    We develop an alternative description of the procedure of vertical integration based on the observation that amplitudes can be written in BRST exact form in the large Hilbert space. We relate this approach to the description of vertical integration given by Sen and Witten.

  6. Vertical Integration, Monopoly, and the First Amendment.

    Science.gov (United States)

    Brennan, Timothy J.

    This paper addresses the relationship between the First Amendment, monopoly of transmission media, and vertical integration of transmission and content provision. A survey of some of the incentives a profit-maximizing transmission monopolist may have with respect to content is followed by a discussion of how vertical integration affects those…

  7. Moving vertices to make drawings plane

    NARCIS (Netherlands)

    Goaoc, X.; Kratochvil, J.; Okamoto, Y.; Shin, C.S.; Wolff, A.; Hong, S.K.; Nishizeki, T.; Quan, W.

    2008-01-01

    In John Tantalo’s on-line game Planarity the player is given a non-plane straight-line drawing of a planar graph. The aim is to make the drawing plane as quickly as possible by moving vertices. In this paper we investigate the related problem MinMovedVertices which asks for the minimum number of

  8. Compact akinetic swept source optical coherence tomography angiography at 1060 nm supporting a wide field of view and adaptive optics imaging modes of the posterior eye.

    Science.gov (United States)

    Salas, Matthias; Augustin, Marco; Felberer, Franz; Wartak, Andreas; Laslandes, Marie; Ginner, Laurin; Niederleithner, Michael; Ensher, Jason; Minneman, Michael P; Leitgeb, Rainer A; Drexler, Wolfgang; Levecq, Xavier; Schmidt-Erfurth, Ursula; Pircher, Michael

    2018-04-01

    Imaging of the human retina with high resolution is an essential step towards improved diagnosis and treatment control. In this paper, we introduce a compact, clinically user-friendly instrument based on swept source optical coherence tomography (SS-OCT). A key feature of the system is the realization of two different operation modes. The first operation mode is similar to conventional OCT imaging and provides large field of view (FoV) images (up to 45° × 30°) of the human retina and choroid with standard resolution. The second operation mode enables it to optically zoom into regions of interest with high transverse resolution using adaptive optics (AO). The FoV of this second operation mode (AO-OCT mode) is 3.0° × 2.8° and enables the visualization of individual retinal cells such as cone photoreceptors or choriocapillaris. The OCT engine is based on an akinetic swept source at 1060 nm and provides an A-scan rate of 200 kHz. Structural as well as angiographic information can be retrieved from the retina and choroid in both operational modes. The capabilities of the prototype are demonstrated in healthy and diseased eyes.

  9. TiO2 nanoparticles as exogenous contrast agent for 1 µm swept source optical coherence tomography: an in vitro study

    Science.gov (United States)

    Kumar, Atul; Mondal, Indranil; Roy, Poulomi; Poddar, Raju

    2018-03-01

    Optical coherence tomography (OCT) is a rapidly evolving, robust technology that has profoundly changed the practice of medical imaging. Swept source OCT (SSOCT) combines the standard time domain and the spatially encoded frequency domain OCT. We have employed a high-speed SSOCT system that utilizes a swept source laser with an A-scan rate of 100 kHz and a central wavelength of 1060 nm for the imaging of the tissue. SSOCT at 1060 nm allows for high penetration in the tissue. TiO2 nanoparticles (NPs) are mostly used for various experimental purposes as an exogenous imaging contrast agent. The in vitro imaging of chicken breast tissue is performed with and without the application of TiO2 NPs for exogenous contrast. Characterization of the chemically synthesized TiO2 NPs was done with dynamic light scattering and a scanning electron microscope method. The effect of TiO2 is studied at different exposure times. A significant improvement in the contrast to noise ratio has been observed through the in vitro imaging of a TiO2 treated tissue.

  10. Vertical barriers with increased sorption capacities

    International Nuclear Information System (INIS)

    Bradl, H.B.

    1997-01-01

    Vertical barriers are commonly used for the containment of contaminated areas. Due to the very small permeability of the barrier material which is usually in the order of magnitude of 10-10 m/s or less the advective contaminant transport can be more or less neglected. Nevertheless, there will always be a diffusive contaminant transport through the barrier which is caused by the concentration gradient. Investigations have been made to increase the sorption capacity of the barrier material by adding substances such as organoclays, zeolites, inorganic oxides and fly ashes. The contaminants taken into account where heavy metals (Pb) and for organic contaminants Toluole and Phenantrene. The paper presents results of model calculations and experiments. As a result, barrier materials can be designed 'tailor-made' depending on the individual contaminant range of each site (e.g. landfills, gasworks etc.). The parameters relevant for construction such as rheological properties, compressive strength and permeability are not affected by the addition of the sorbents

  11. Functionalization of vertically aligned carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Eloise Van Hooijdonk

    2013-02-01

    Full Text Available This review focuses and summarizes recent studies on the functionalization of carbon nanotubes oriented perpendicularly to their substrate, so-called vertically aligned carbon nanotubes (VA-CNTs. The intrinsic properties of individual nanotubes make the VA-CNTs ideal candidates for integration in a wide range of devices, and many potential applications have been envisaged. These applications can benefit from the unidirectional alignment of the nanotubes, the large surface area, the high carbon purity, the outstanding electrical conductivity, and the uniformly long length. However, practical uses of VA-CNTs are limited by their surface characteristics, which must be often modified in order to meet the specificity of each particular application. The proposed approaches are based on the chemical modifications of the surface by functionalization (grafting of functional chemical groups, decoration with metal particles or wrapping of polymers to bring new properties or to improve the interactions between the VA-CNTs and their environment while maintaining the alignment of CNTs.

  12. Mandible vertical height correction using lingual bone-split pedicle onlay graft technique

    Directory of Open Access Journals (Sweden)

    Coen Pramono D

    2006-09-01

    Full Text Available As edentulous mandible become atrophic, a denture bearing area will also be reduced. Difficulty in the removable prosthesis rehabilitation will be present as well. The purpose of this paper reports an innovative surgical technique to cope a problem of unstable complete lower denture due to bone atrophy and resulted of vertical height reduction of the anterior region of the mandible necessary for denture retention. Vertical advancement of the lower jaw using lingual bone split pedicle onlay graft technique in the anterior region of the mandible and followed by secondary epithelization vestibuloplasty in achieving the vertical height dimension. The surgery was achieved satisfactorily as the vertical dimension of the mandible anterior region had increased and the denture seated more stable comparing with the previous denture worn by the patient. It concluded that the surgery was achieved with a great result as the vertical height of the anterior region of the mandible had increased positively therefore lead the denture seated more stable.

  13. Development of Vertical Cable Seismic System (3)

    Science.gov (United States)

    Asakawa, E.; Murakami, F.; Tsukahara, H.; Mizohata, S.; Ishikawa, K.

    2013-12-01

    The VCS (Vertical Cable Seismic) is one of the reflection seismic methods. It uses hydrophone arrays vertically moored from the seafloor to record acoustic waves generated by surface, deep-towed or ocean bottom sources. Analyzing the reflections from the sub-seabed, we could look into the subsurface structure. Because VCS is an efficient high-resolution 3D seismic survey method for a spatially-bounded area, we proposed the method for the hydrothermal deposit survey tool development program that the Ministry of Education, Culture, Sports, Science and Technology (MEXT) started in 2009. We are now developing a VCS system, including not only data acquisition hardware but data processing and analysis technique. We carried out several VCS surveys combining with surface towed source, deep towed source and ocean bottom source. The water depths of the survey are from 100m up to 2100m. The target of the survey includes not only hydrothermal deposit but oil and gas exploration. Through these experiments, our VCS data acquisition system has been completed. But the data processing techniques are still on the way. One of the most critical issues is the positioning in the water. The uncertainty in the positions of the source and of the hydrophones in water degraded the quality of subsurface image. GPS navigation system are available on sea surface, but in case of deep-towed source or ocean bottom source, the accuracy of shot position with SSBL/USBL is not sufficient for the very high-resolution imaging. We have developed another approach to determine the positions in water using the travel time data from the source to VCS hydrophones. In the data acquisition stage, we estimate the position of VCS location with slant ranging method from the sea surface. The deep-towed source or ocean bottom source is estimated by SSBL/USBL. The water velocity profile is measured by XCTD. After the data acquisition, we pick the first break times of the VCS recorded data. The estimated positions of

  14. Development of Vertical Cable Seismic System

    Science.gov (United States)

    Asakawa, E.; Murakami, F.; Sekino, Y.; Okamoto, T.; Ishikawa, K.; Tsukahara, H.; Shimura, T.

    2011-12-01

    In 2009, Ministry of Education, Culture, Sports, Science and Technology(MEXT) started the survey system development for Hydrothermal deposit. We proposed the Vertical Cable Seismic (VCS), the reflection seismic survey with vertical cable above seabottom. VCS has the following advantages for hydrothermal deposit survey. (1) VCS is an efficient high-resolution 3D seismic survey in limited area. (2) It achieves high-resolution image because the sensors are closely located to the target. (3) It avoids the coupling problems between sensor and seabottom that cause serious damage of seismic data quality. (4) Because of autonomous recording system on sea floor, various types of marine source are applicable with VCS such as sea-surface source (GI gun etc.) , deep-towed or ocean bottom source. Our first experiment of 2D/3D VCS surveys has been carried out in Lake Biwa, JAPAN, in November 2009. The 2D VCS data processing follows the walk-away VSP, including wave field separation and depth migration. Seismic Interferometry technique is also applied. The results give much clearer image than the conventional surface seismic. Prestack depth migration is applied to 3D data to obtain good quality 3D depth volume. Seismic Interferometry technique is applied to obtain the high resolution image in the very shallow zone. Based on the feasibility study, we have developed the autonomous recording VCS system and carried out the trial experiment in actual ocean at the water depth of about 400m to establish the procedures of deployment/recovery and to examine the VC position or fluctuation at seabottom. The result shows that the VC position is estimated with sufficient accuracy and very little fluctuation is observed. Institute of Industrial Science, the University of Tokyo took the research cruise NT11-02 on JAMSTEC R/V Natsushima in February, 2011. In the cruise NT11-02, JGI carried out the second VCS survey using the autonomous VCS recording system with the deep towed source provided by

  15. Regional Phenomena of Vertical Deformation in Southern Part of Indonesia

    Science.gov (United States)

    Sarsito, D. A.; Susilo; Andreas, H.; Pradipta, D.; Gumilar, I.

    2018-02-01

    Distribution of present-day horizontal and vertical deformation across the Southern Part of Indonesia at Java, Bali and Nusa Tenggara now days can be determined from continuous and campaign types of GNSS GPS data monitoring. For vertical deformation in this case we use the continuous types since they are give better quality of data consistency compare to campaign type. Continuous Global Positioning System (CGPS) are maintaining by Geospatial Information Agency for more than a decade. The vertical displacements or velocity rates are estimated from time series analysis after multi-baseline GPS processing using GAMIT-GLOBK software with respect to the latest International Terrestrial Reference Frame. The result shows some interesting phenomena where the northern part of research area majority have negative value that may indicate land subsidence with or without tectonic subsidence combination. In the middle part, the uplift phenomena are clearly shown and in the southern part show combine pattern between uplift and subsidence. The impacts of those phenomena would be discuss also in this paper since many population and infrastructure are located in the areas that will need more protection planning to reduce the negative impact such as earthquake and flooding.

  16. COMPUTING VERTICES OF INTEGER PARTITION POLYTOPES

    Directory of Open Access Journals (Sweden)

    A. S. Vroublevski

    2015-01-01

    Full Text Available The paper describes a method of generating vertices of the polytopes of integer partitions that was used by the authors to calculate all vertices and support vertices of the partition polytopes for all n ≤ 105 and all knapsack partitions of n ≤ 165. The method avoids generating all partitions of n. The vertices are determined with the help of sufficient and necessary conditions; in the hard cases, the well-known program Polymake is used. Some computational aspects are exposed in more detail. These are the algorithm for checking the criterion that characterizes partitions that are convex combinations of two other partitions; the way of using two combinatorial operations that transform the known vertices to the new ones; and employing the Polymake to recognize a limited number (for small n of partitions that need three or more other partitions for being convexly expressed. We discuss the computational results on the numbers of vertices and support vertices of the partition polytopes and some appealing problems these results give rise to.

  17. Small Vertical Axis Wind Turbines: aerodynamics and starting behavior

    Directory of Open Access Journals (Sweden)

    Horia DUMITRESCU

    2013-12-01

    Full Text Available In urban areas the wind is very turbulent and unstable with fast changes in direction andvelocity. In these environments, the use of small vertical axis wind turbines (VAWT becomesincreasingly attractive due to several advantages over horizontal axis wind turbines (HAWT.However, such designs have received much less attention than the more common propeller-typedesigns and the understanding of same aspects of their operation remains, to this day, incomplete.This is particularly true of their starting characteristics. Indeed, same authors heuristically maintainthat they cannot start without external assistance. This paper reviews the cause of the inability of thelow solidity fixed pitch vertical axis wind turbines to self-start, and investigates the way ofovercoming this draw back.

  18. ISAL experiment documentation of vertical tail and OMS pods

    Science.gov (United States)

    1983-01-01

    Investigation of Space Transportation System (STS) Atmospheric Luminosities (ISAL) experiment documentation includes vertical tail and orbital maneuvering system (OMS) pods with surface glow against the blackness of space. This glowing scene was provided by a long duration exposure with a 35mm camera aimed toward the tail of the Earth-orbiting Challenger, Orbiter Vehicle (OV) 099. OV-099 was maneuvered to a 120-nautical-mile altitude and flown with open payload bay (PLB) in the velocity vector for the conducting of a test titled, 'Evaluation of Oxygen Interaction with Materials (EOIM)'. Atomic oxygen within the low orbital environment is known to be extremely reactive when in contact with solid surfaces. In the darkened area between the camera and the glowing OMS pods and vertical stabilizer are two trays of test materials.

  19. Flow regimes and heat transfer in vertical narrow annuli

    International Nuclear Information System (INIS)

    Ulke, A.; Goldberg, I.

    1993-01-01

    In shell side boiling heat exchangers narrow crevices that are formed between the tubes and the tube support structure provide areas for local thermal-hydraulic conditions which differ significantly from bulk fluid conditions. Understanding of the processes of boiling and dryout in flow restricted crevices can help in designing of tube support geometries to minimize the likelihood of tube support plate and tube corrosion observed in commercial power plant steam generators. This paper describes a one dimensional thermal-hydraulic model of a vertical crevice between a tube and a support plate with cylindrical holes. The annulus formed by the support plate hole and an eccentrically located tube has been represented by vertical strips. The formation, growth and collapse of a steam bubble in each strip has been determined. Based on the bubble history, and flow regimes characterized by ''isolated'' bubbles, ''coalesced'' bubbles and liquid deficient regions have been defined

  20. Vertical Motions of Oceanic Volcanoes

    Science.gov (United States)

    Clague, D. A.; Moore, J. G.

    2006-12-01

    lasting a few hundred thousand years as the island migrates over a broad flexural arch related to isostatic compensation of a nearby active volcano. The arch is located about 190±30 km away from the center of volcanic activity and is also related to the rejuvenated volcanic stage on the islands. Reefs on Oahu that are uplifted several tens of m above sea level are the primary evidence for uplift as the islands over-ride the flexural arch. At the other end of the movement spectrum, both in terms of magnitude and length of response, are the rapid uplift and subsidence that occurs as magma is accumulated within or erupted from active submarine volcanoes. These changes are measured in days to years and are of cm to m variation; they are measured using leveling surveys, tiltmeters, EDM and GPS above sea level and pressure gauges and tiltmeters below sea level. Other acoustic techniques to measure such vertical movement are under development. Elsewhere, evidence for subsidence of volcanoes is also widespread, ranging from shallow water carbonates on drowned Cretaceous guyots, to mapped shoreline features, to the presence of subaerially-erupted (degassed) lavas on now submerged volcanoes. Evidence for uplift is more limited, but includes makatea islands with uplifted coral reefs surrounding low volcanic islands. These are formed due to flexural uplift associated with isostatic loading of nearby islands or seamounts. In sum, oceanic volcanoes display a long history of subsidence, rapid at first and then slow, sometimes punctuated by brief periods of uplift due to lithospheric loading by subsequently formed nearby volcanoes.

  1. Measuring of vertical stroke Vub vertical stroke in the forthcoming decade

    International Nuclear Information System (INIS)

    Kim, C.S.

    1997-01-01

    I first introduce the importance of measuring V ub precisely. Then, from a theoretician's point of view, I review (a) past history, (b) present trials, and (c) possible future alternatives on measuring vertical stroke V ub vertical stroke and/or vertical stroke V ub /V cb vertical stroke. As of my main topic, I introduce a model-independent method, which predicts Γ(B→X u lν)/Γ(B→X c lν)≡(γ u /γ c ) x vertical stroke V ub /V cb vertical stroke 2 ≅(1.83±0.28) x vertical stroke V ub /V cb vertical stroke 2 and vertical stroke V ub /V cb vertical stroke ≡(γ c /γ u ) 1/2 x [B(B→X u lν)/B(B→ X c lν]) 1/2 ≅(0.74±0.06) x [B(B→X u lν/)B(B→X c lν)] 1/2 , based on the heavy quark effective theory I also explore the possible experimental options to separate B→X u lν from the dominant B→X c lν: the measurement of inclusive hadronic invariant mass distributions, and the 'D-π' (and 'K-π') separation conditions I also clarify the relevant experimental backgrounds. (orig.)

  2. determination of verticality of reservoir engineering structure

    African Journals Online (AJOL)

    user

    applications is 3D survey and management of oil and gas facilities and other engineering structures. This recent .... also affect ground water contamination. 2. VERTICALITY ...... The soil, water and concrete in a Reservoir at the foundation bed ...

  3. Vertical activity estimation using 2D radar

    CSIR Research Space (South Africa)

    Hakl, H

    2008-12-01

    Full Text Available Understanding airspace activity is essential for airspace control. Being able to detect vertical activity in aircraft allows prediction of aircraft intent, thereby allowing more accurate situation awareness and correspondingly more appropriate...

  4. HL-LHC vertical cryostat during construction

    CERN Multimedia

    Lanaro, Andrea

    2016-01-01

    7m high "Cluster D" vertical test cryostat during construction at contractor's premises, Alca Technology Srl, in Schio, Italy. The inner helium vessel with its heat exchanger are visible. To be installed in the D pit in SMA18.

  5. Prefabricated vertical drains, vol. I : engineering guidelines.

    Science.gov (United States)

    1986-09-01

    This volume presents procedures and guidelines applicable to the design and instal : tion of prefabricated vertical drains to accelerate consolidation of soils. The : contents represent the Consultant's interpretation of the state-of-the-art as of : ...

  6. Electrically Pumped Vertical-Cavity Amplifiers

    DEFF Research Database (Denmark)

    Greibe, Tine

    2007-01-01

    In this work, the design of electrically pumped vertical cavity semiconductor optical amplifiers (eVCAs) for use in a mode-locked external-cavity laser has been developed, investigated and analysed. Four different eVCAs, one top-emitting and three bottom emitting structures, have been designed...... and discussed. The thesis concludes with recommendations for further work towards the realisation of compact electrically pumped mode-locked vertical externalcavity surface emitting lasers....

  7. Vertical Josephson Interferometer for Tunable Flux Qubit

    Energy Technology Data Exchange (ETDEWEB)

    Granata, C [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I- 80078, Pozzuoli (Italy); Vettoliere, A [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I- 80078, Pozzuoli (Italy); Lisitskiy, M [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I- 80078, Pozzuoli (Italy); Rombetto, S [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I- 80078, Pozzuoli (Italy); Russo, M [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I- 80078, Pozzuoli (Italy); Ruggiero, B [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I- 80078, Pozzuoli (Italy); Corato, V [Dipartimento di Ingegneria dell' Informazione, Seconda Universita di Napoli, I-8 1031, Aversa (Italy) and Istituto di Cibernetica ' E. Caianiello' del CNR, I-80078, Pozzuoli (Italy); Russo, R [Dipartimento di Ingegneria dell' Informazione, Seconda Universita di Napoli, I-8 1031, Aversa (Italy) and Istituto di Cibernetica ' E. Caianiello' del CNR, I-80078, Pozzuoli (Italy); Silvestrini, P [Dipartimento di Ingegneria dell' Informazione, Seconda Universita di Napoli, I-8 1031, Aversa (Italy) and Istituto di Cibernetica ' E. Caianiello' del CNR, I-80078, Pozzuoli (Italy)

    2006-06-01

    We present a niobium-based Josephson device as prototype for quantum computation with flux qubits. The most interesting feature of this device is the use of a Josephson vertical interferometer to tune the flux qubit allowing the control of the off-diagonal Hamiltonian terms of the system. In the vertical interferometer, the Josephson current is precisely modulated from a maximum to zero with fine control by a small transversal magnetic field parallel to the rf superconducting loop plane.

  8. Vertical Scan-Conversion for Filling Purposes

    OpenAIRE

    Hersch, R. D.

    1988-01-01

    Conventional scan-conversion algorithms were developed independently of filling algorithms. They cause many problems, when used for filling purposes. However, today's raster printers and plotters require extended use of filling, especially for the generation of typographic characters and graphic line art. A new scan-conversion algorithm, called vertical scan-conversion has been specifically designed to meet the requirements of parity scan line fill algorithms. Vertical scan-conversion ensures...

  9. Spirit Near 'Stapledon' on Sol 1802 (Vertical)

    Science.gov (United States)

    2009-01-01

    NASA Mars Exploration Rover Spirit used its navigation camera for the images assembled into this full-circle view of the rover's surroundings during the 1,802nd Martian day, or sol, (January 26, 2009) of Spirit's mission on the surface of Mars. North is at the top. This view is presented as a vertical projection with geometric seam correction. Spirit had driven down off the low plateau called 'Home Plate' on Sol 1782 (January 6, 2009) after spending 12 months on a north-facing slope on the northern edge of Home Plate. The position on the slope (at about the 9-o'clock position in this view) tilted Spirit's solar panels toward the sun, enabling the rover to generate enough electricity to survive its third Martian winter. Tracks at about the 11-o'clock position of this panorama can be seen leading back to that 'Winter Haven 3' site from the Sol 1802 position about 10 meters (33 feet) away. For scale, the distance between the parallel wheel tracks is about one meter (40 inches). Where the receding tracks bend to the left, a circular pattern resulted from Spirit turning in place at a soil target informally named 'Stapledon' after William Olaf Stapledon, a British philosopher and science-fiction author who lived from 1886 to 1950. Scientists on the rover team suspected that the soil in that area might have a high concentration of silica, resembling a high-silica soil patch discovered east of Home Plate in 2007. Bright material visible in the track furthest to the right was examined with Spirit's alpha partical X-ray spectrometer and found, indeed, to be rich in silica. The team laid plans to drive Spirit from this Sol 1802 location back up onto Home Plate, then southward for the rover's summer field season.

  10. Overview and Design of self-acting pitch control mechanism for vertical axis wind turbine using multi body simulation approach

    DEFF Research Database (Denmark)

    Chougule, Prasad; Nielsen, Søren R.K.

    2014-01-01

    Awareness about wind energy is constantly growing in the world. Especially a demand for small scale wind turbine is increasing and various products are available in market. There are mainly two types of wind turbines, horizontal axis wind turbine and vertical axis wind turbines. Horizontal axis...... wind turbines are suitable for high wind speed whereas vertical axis wind turbines operate relatively low wind speed area. Vertical axis wind turbines are cost effective and simple in construction as compared to the horizontal axis wind turbine. However, vertical axis wind turbines have inherent...

  11. Near vertical incidence skywave propagation: Elevation angles and optimum antenna height for horizontal dipole antennas

    NARCIS (Netherlands)

    Witvliet, Ben A.; van Maanen, Erik; Petersen, George J.; Westenberg, Albert J.; Bentum, Marinus Jan; Slump, Cornelis H.; Schiphorst, Roelof

    2015-01-01

    Near Vertical Incidence Skywave (NVIS) communication uses the ionosphere as a reflector to cover a continuous area with a radius of at least 150 km around the transmitter, on frequencies typically between 3 and 10 MHz. In developing countries, in areas lacking any other telecommunication

  12. A vectorization of the Jameson-Caughey NYU transonic swept-wing computer program FLO-22-V1 for the STAR-100 computer

    Science.gov (United States)

    Smith, R. E.; Pitts, J. I.; Lambiotte, J. J., Jr.

    1978-01-01

    The computer program FLO-22 for analyzing inviscid transonic flow past 3-D swept-wing configurations was modified to use vector operations and run on the STAR-100 computer. The vectorized version described herein was called FLO-22-V1. Vector operations were incorporated into Successive Line Over-Relaxation in the transformed horizontal direction. Vector relational operations and control vectors were used to implement upwind differencing at supersonic points. A high speed of computation and extended grid domain were characteristics of FLO-22-V1. The new program was not the optimal vectorization of Successive Line Over-Relaxation applied to transonic flow; however, it proved that vector operations can readily be implemented to increase the computation rate of the algorithm.

  13. Applicability of linearized-theory attached-flow methods to design and analysis of flap systems at low speeds for thin swept wings with sharp leading edges

    Science.gov (United States)

    Carlson, Harry W.; Darden, Christine M.

    1987-01-01

    Low-speed experimental force and data on a series of thin swept wings with sharp leading edges and leading and trailing-edge flaps are compared with predictions made using a linearized-theory method which includes estimates of vortex forces. These comparisons were made to assess the effectiveness of linearized-theory methods for use in the design and analysis of flap systems in subsonic flow. Results demonstrate that linearized-theory, attached-flow methods (with approximate representation of vortex forces) can form the basis of a rational system for flap design and analysis. Even attached-flow methods that do not take vortex forces into account can be used for the selection of optimized flap-system geometry, but design-point performance levels tend to be underestimated unless vortex forces are included. Illustrative examples of the use of these methods in the design of efficient low-speed flap systems are included.

  14. Linear and nonlinear development of controlled disturbances in the supersonic boundary layer on a swept wing at Mach 2.5

    International Nuclear Information System (INIS)

    Kolosov, G L; Kosinov, A D

    2016-01-01

    Experimental data on the linear and nonlinear wave train development in 3D supersonic boundary layer over a 45° swept-wing at Mach number 2.5 are presented. Travelling artificial disturbances were introduced in the boundary layer by periodical glow discharge at frequencies 10 and 20 kHz. The spatial-temporal and spectral-wave characteristics of the wave train of unstable disturbances in the linear region are obtained. It is shown that the additional peaks in β '-spectra arise for both subharmonic and fundamental frequencies. The experiments indicate the presence of subharmonic resonance mechanism in 3D boundary layer at Mach number 2.5. (paper)

  15. Real-time calibration-free C-scan images of the eye fundus using Master Slave swept source optical coherence tomography

    Science.gov (United States)

    Bradu, Adrian; Kapinchev, Konstantin; Barnes, Fred; Garway-Heath, David F.; Rajendram, Ranjan; Keane, Pearce; Podoleanu, Adrian G.

    2015-03-01

    Recently, we introduced a novel Optical Coherence Tomography (OCT) method, termed as Master Slave OCT (MS-OCT), specialized for delivering en-face images. This method uses principles of spectral domain interfereometry in two stages. MS-OCT operates like a time domain OCT, selecting only signals from a chosen depth only while scanning the laser beam across the eye. Time domain OCT allows real time production of an en-face image, although relatively slowly. As a major advance, the Master Slave method allows collection of signals from any number of depths, as required by the user. The tremendous advantage in terms of parallel provision of data from numerous depths could not be fully employed by using multi core processors only. The data processing required to generate images at multiple depths simultaneously is not achievable with commodity multicore processors only. We compare here the major improvement in processing and display, brought about by using graphic cards. We demonstrate images obtained with a swept source at 100 kHz (which determines an acquisition time [Ta] for a frame of 200×200 pixels2 of Ta =1.6 s). By the end of the acquired frame being scanned, using our computing capacity, 4 simultaneous en-face images could be created in T = 0.8 s. We demonstrate that by using graphic cards, 32 en-face images can be displayed in Td 0.3 s. Other faster swept source engines can be used with no difference in terms of Td. With 32 images (or more), volumes can be created for 3D display, using en-face images, as opposed to the current technology where volumes are created using cross section OCT images.

  16. The minimal access deep plane extended vertical facelift.

    Science.gov (United States)

    Jacono, Andrew A; Parikh, Sachin S

    2011-11-01

    result with few complications and minimal downtime. The MADE vertical facelift fulfills these criteria and often yields superior results in the midface and neck areas, where many short scar techniques fail. Furthermore, this procedure can be performed under local anesthesia, which is a benefit to both patients and surgeons.

  17. Simulation of flooding waves in vertical churn flow

    Energy Technology Data Exchange (ETDEWEB)

    Tekavčič, Matej, E-mail: matej.tekavcic@ijs.si; Končar, Boštjan; Kljenak, Ivo

    2016-04-01

    Highlights: • Flooding waves in air–water churn flow in a vertical pipe were studied. • Simulations using two-fluid model with interface sharpening were performed. • Calculated wave amplitudes agree with existing experimental data. • Contributions of force terms in the liquid momentum balance equation are presented. - Abstract: A transient simulation of flooding waves in the churn flow of air and water in a vertical pipe is performed by the means of two-fluid modelling approach with interface sharpening. The gas and liquid phases are considered immiscible and incompressible with no mass transfer between them. Inter-phase coupling of momentum is realized via interface drag force which is based on the interface area density and the relative velocity between the phases. Surface tension effects are modelled with the Continuum Surface Model. The flow is assumed isothermal. Turbulence is modelled for each phase separately using the two-equation eddy viscosity approach. Results are compared with the reported experimental data for churn flow regime in a vertical pipe (Wang et al., 2011a). Reynolds numbers of the gas flow are in the range from 6000 to 10,000, while the liquid mass flow rate upwards ranges from 25 to 32 g/s. Prediction of critical and maximum amplitudes of the flooding waves show good agreement with experimental values. Results for wave frequencies indicate significant deviations, which can be attributed to the choice of the liquid inlet model.

  18. Vertically mounted bifacial photovoltaic modules: A global analysis

    International Nuclear Information System (INIS)

    Guo, Siyu; Walsh, Timothy Michael; Peters, Marius

    2013-01-01

    Bifacial PV (photovoltaic) modules have recently come to increasing attention and various system designs have been investigated. In this paper, a global comparison is made between vertically mounted bifacial modules facing East–West and conventionally mounted mono-facial modules. An analytical method is used to calculate the radiation received by these two module configurations. It is found that the answer to the question which of these two module configurations performs better strongly depends on three factors: (i) the latitude, (ii) the local diffuse fraction and (iii) the albedo. In a subsequent part of the paper, the minimum albedo required to result in a better performance for vertically mounted bifacial modules is calculated for every place in the world. The calculation is based on measured data of the diffuse light fraction and the results are shown in the form of a global map. Finally, the albedo requirements are compared with the measured global albedo distribution. The calculation allows a distinct decision which module configuration is more suitable for a certain place in the world. The result is also shown as a map defining the corresponding areas. - Highlights: • Vertically mounted bifacial module and conventionally monofacial module are compared. • The key factors affecting the performance of the two configurations are investigated. • Which module configuration is more suitable for each place is shown in a world map. • The minimum albedo for bifacial modules to have a better performance is calculated

  19. Changes in Quality of Health Care Delivery after Vertical Integration.

    Science.gov (United States)

    Carlin, Caroline S; Dowd, Bryan; Feldman, Roger

    2015-08-01

    To fill an empirical gap in the literature by examining changes in quality of care measures occurring when multispecialty clinic systems were acquired by hospital-owned, vertically integrated health care delivery systems in the Twin Cities area. Administrative data for health plan enrollees attributed to treatment and control clinic systems, merged with U.S. Census data. We compared changes in quality measures for health plan enrollees in the acquired clinics to enrollees in nine control groups using a differences-in-differences model. Our dataset spans 2 years prior to and 4 years after the acquisitions. We estimated probit models with errors clustered within enrollees. Data were assembled by the health plan's informatics team. Vertical integration is associated with increased rates of colorectal and cervical cancer screening and more appropriate emergency department use. The probability of ambulatory care-sensitive admissions increased when the acquisition caused disruption in admitting patterns. Moving a clinic system into a vertically integrated delivery system resulted in limited increases in quality of care indicators. Caution is warranted when the acquisition causes disruption in referral patterns. © Health Research and Educational Trust.

  20. Simulation of flooding waves in vertical churn flow

    International Nuclear Information System (INIS)

    Tekavčič, Matej; Končar, Boštjan; Kljenak, Ivo

    2016-01-01

    Highlights: • Flooding waves in air–water churn flow in a vertical pipe were studied. • Simulations using two-fluid model with interface sharpening were performed. • Calculated wave amplitudes agree with existing experimental data. • Contributions of force terms in the liquid momentum balance equation are presented. - Abstract: A transient simulation of flooding waves in the churn flow of air and water in a vertical pipe is performed by the means of two-fluid modelling approach with interface sharpening. The gas and liquid phases are considered immiscible and incompressible with no mass transfer between them. Inter-phase coupling of momentum is realized via interface drag force which is based on the interface area density and the relative velocity between the phases. Surface tension effects are modelled with the Continuum Surface Model. The flow is assumed isothermal. Turbulence is modelled for each phase separately using the two-equation eddy viscosity approach. Results are compared with the reported experimental data for churn flow regime in a vertical pipe (Wang et al., 2011a). Reynolds numbers of the gas flow are in the range from 6000 to 10,000, while the liquid mass flow rate upwards ranges from 25 to 32 g/s. Prediction of critical and maximum amplitudes of the flooding waves show good agreement with experimental values. Results for wave frequencies indicate significant deviations, which can be attributed to the choice of the liquid inlet model.

  1. Study a possibility of saffron (Crocus sativus L. production in vertical culture

    Directory of Open Access Journals (Sweden)

    Lorin ali ahmad

    2017-06-01

    Full Text Available In recent years many research studies have been carried out to use a vertical planting system for production of some plants. Although saffron is one of the most expensive spices in the word, there is no investigation about saffron production in a vertical planting system. Therefore, the growth and production of saffron plant in two different systems (vertical and horizontal were studied in the agricultural research field of the Tarbiat Modares University during the 2013-2014 growing seasons. In the vertical system, saffron corms were planted in fabric bags containing potting soil. The fabric bags were hanged on a cube of metal with an area of each side of the cube being equal to 2.25 square meters. In the horizontal system, the corms were planted in three plots with the area of each plots being 2.25 square meters. The results showed that in the vertical planting system, the number of flowers, flower dry weight and dry weight of stigma per unit area of land (10 flower, 347.34 and 0.56 mg respectively were significantly higher than those obtained in the horizontal culture (They were almost three times higher .In contrast, the numbers and dry weight of lateral corms (2.4 corm and 0.36 g respectively and the dry weight of apical corm (0.88 g in the horizontal system were significantly greater than those obtained in the vertical system. Dry weight of leaf and root were significantly greater in the vertical system. The total number of buds and leaves were more in the horizontal culture. However, the maximum leaf length of the vertical planting system was higher than those of the horizontal system.

  2. Possible vertical transmission of Bartonella bacilliformis in Peru.

    Science.gov (United States)

    Tuya, Ximena L; Escalante-Kanashiro, Raffo; Tinco, Carmen; Pons, Maria J; Petrozzi, Verónica; Ruiz, Joaquim; del Valle, Juana

    2015-01-01

    A 22-day-old male was admitted with a 2-day history of irritability, dyspnea, jaundice, fever, and gastrointestinal bleeding. A thin blood smear was performed, which showed the presence of intraerythrocyte bacteria identified as Bartonella bacilliformis, and subsequently, the child was diagnosed with Carrion's disease. The diagnosis was confirmed by specific polymerase chain reaction. The child was born in a non-endemic B. bacilliformis area and had not traveled to such an area before hospitalization. However, the mother was from an endemic B. bacilliformis area, and posterior physical examination showed the presence of a wart compatible with B. bacilliformis in semi-immune subjects. These data support vertical transmission of B. bacilliformis. © The American Society of Tropical Medicine and Hygiene.

  3. Quality Assessment of Vertical Angular Deviations for Photometer Calibration Benches

    International Nuclear Information System (INIS)

    Ribeiro, A Silva; Santos, A Costa; E Sousa, J Alves; Forbes, A B

    2015-01-01

    Lighting, both natural and electric, constitutes one of the most important aspects of the life of human beings, allowing us to see and perform our daily tasks in outdoor and indoor environments. The safety aspects of lighting are self-evident in areas such as road lighting, urban lighting and also indoor lighting. The use of photometers to measure lighting levels requires traceability obtained in accredited laboratories, which must provide an associated uncertainty. It is therefore relevant to study the impact of known uncertainty sources like the vertical angular deviation of photometer calibration benches, in order to define criteria to its quality assessment

  4. Vertical integration in the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Mommsen, J.T.

    1977-01-01

    Vertical integration in the nuclear fuel cycle and its contribution to market power of integrated fuel suppliers were studied. The industry subdivision analyzed is the uranium raw materials sector. The hypotheses demonstrated are that (1) this sector of the industry is trending toward vertical integration between production of uranium raw materials and the manufacture of nuclear fuel elements, and (2) this vertical integration confers upon integrated firms a significant market advantage over non-integrated fuel manufacturers. Under microeconomic concepts the rationale for vertical integration is the pursuit of efficiency, and it is beneficial because it increases physical output and decreases price. The Market Advantage Model developed is an arithmetical statement of the relative market power (in terms of price) between non-integrated nuclear fuel manufacturers and integrated raw material/fuel suppliers, based on the concept of the ''squeeze.'' In operation, the model compares net profit and return on sales of nuclear fuel elements between the competitors, under different price and cost circumstances. The model shows that, if integrated and non-integrated competitors sell their final product at identical prices, the non-integrated manufacturer returns a net profit only 17% of the integrated firm. Also, the integrated supplier can price his product 35% below the non-integrated producer's price and still return the same net profit. Vertical integration confers a definite market advantage to the integrated supplier, and the basic source of that advantage is the cost-price differential of the raw material, uranium

  5. Climatology of tropospheric vertical velocity spectra

    Science.gov (United States)

    Ecklund, W. L.; Gage, K. S.; Balsley, B. B.; Carter, D. A.

    1986-01-01

    Vertical velocity power spectra obtained from Poker Flat, Alaska; Platteville, Colorado; Rhone Delta, France; and Ponape, East Caroline Islands using 50-MHz clear-air radars with vertical beams are given. The spectra were obtained by analyzing the quietest periods from the one-minute-resolution time series for each site. The lengths of available vertical records ranged from as long as 6 months at Poker Flat to about 1 month at Platteville. The quiet-time vertical velocity spectra are shown. Spectral period ranging from 2 minutes to 4 hours is shown on the abscissa and power spectral density is given on the ordinate. The Brunt-Vaisala (B-V) periods (determined from nearby sounding balloons) are indicated. All spectra (except the one from Platteville) exhibit a peak at periods slightly longer than the B-V period, are flat at longer periods, and fall rapidly at periods less than the B-V period. This behavior is expected for a spectrum of internal waves and is very similar to what is observed in the ocean (Eriksen, 1978). The spectral amplitudes vary by only a factor of 2 or 3 about the mean, and show that under quiet conditions vertical velocity spectra from the troposphere are very similar at widely different locations.

  6. A Physician's Perspective On Vertical Integration.

    Science.gov (United States)

    Berenson, Robert A

    2017-09-01

    Vertical integration has been a central feature of health care delivery system change for more than two decades. Recent studies have demonstrated that vertically integrated health care systems raise prices and costs without observable improvements in quality, despite many theoretical reasons why cost control and improved quality might occur. Less well studied is how physicians view their newfound partnerships with hospitals. In this article I review literature findings and other observations on five aspects of vertical integration that affect physicians in their professional and personal lives: patients' access to physicians, physician compensation, autonomy versus system support, medical professionalism and culture, and lifestyle. I conclude that the movement toward physicians' alignment with and employment in vertically integrated systems seems inexorable but that policy should not promote such integration either intentionally or inadvertently. Instead, policy should address the flaws in current payment approaches that reward high prices and excessive service use-outcomes that vertical integration currently produces. Project HOPE—The People-to-People Health Foundation, Inc.

  7. Organizing vertical layout environments: a forward-looking development strategy for high-rise building projects

    Science.gov (United States)

    Magay, A. A.; Bulgakova, E. A.; Zabelina, S. A.

    2018-03-01

    The article highlights issues surrounding development of high rise buildings. With the rapid increase of the global population there has been a trend for people to migrate into megacities and has caused the expansion of big city territories. This trend, coupled with the desire for a comfortable living environment, has resulted in numerous problems plaguing the megacity. This article proposes that a viable solution to the problems facing megacities is to create vertical layout environments. Potential options for creating vertical layout environments are set out below including the construction of buildings with atriums. Further, the article puts forth suggested spatial organization of the environment as well as optimal landscaping of high-rise buildings and constructions for the creation of vertical layout environments. Finally, the persuasive reasons for the adoption of vertical layout environments is that it will decrease the amount of developed urban areas, decrease traffic and increase environmental sustainability.

  8. Vertical Silicon Nanowire Platform for Low Power Electronics and Clean Energy Applications

    Directory of Open Access Journals (Sweden)

    D.-L. Kwong

    2012-01-01

    Full Text Available This paper reviews the progress of the vertical top-down nanowire technology platform developed to explore novel device architectures and integration schemes for green electronics and clean energy applications. Under electronics domain, besides having ultimate scaling potential, the vertical wire offers (1 CMOS circuits with much smaller foot print as compared to planar transistor at the same technology node, (2 a natural platform for tunneling FETs, and (3 a route to fabricate stacked nonvolatile memory cells. Under clean energy harvesting area, vertical wires could provide (1 cost reduction in photovoltaic energy conversion through enhanced light trapping and (2 a fully CMOS compatible thermoelectric engine converting waste-heat into electricity. In addition to progress review, we discuss the challenges and future prospects with vertical nanowires platform.

  9. Measurement of vertical stroke Vcb vertical stroke at the Z energy from B mesons exclusive decays

    International Nuclear Information System (INIS)

    Marinelli, N.

    1998-01-01

    Recent ALEPH, DELPHI and OPAL measurements of the form factors in the exclusive decay modes anti B 0 → D *+ l - anti ν l and anti B 0 →D + l - anti ν l are reviewed here. The values obtained allow an almost model-independent determination of vertical stroke V cb vertical stroke in the HQET framework. (orig.)

  10. Measurement of vertical stroke Vub vertical stroke using b hadron semileptonic decay

    International Nuclear Information System (INIS)

    Abbiendi, G.; Aakesson, P.F.

    2001-01-01

    The magnitude of the CKM matrix element vertical stroke V ub vertical stroke is determined by measuring the inclusive charmless semileptonic branching fraction of beauty hadrons at OPAL based on b → X u lν event topology and kinematics. This analysis uses OPAL data collected between 1991 and 1995, which correspond to about four million hadronic Z decays. We measure Br(b → X u lν) to be (1.63 ±0.53 +0.55 -0.62 ) x 10 -3 . The first uncertainty is the statistical error and the second is the systematic error. From this analysis, vertical stroke V ub vertical stroke is determined to be: vertical stroke V ub vertical stroke =(4.00±0.65(stat) +0.67 -0.76 (sys)±0.19(HQE)) x 10 -3 . The last error represents the theoretical uncertainties related to the extraction of vertical stroke V ub vertical stroke from Br(b→X u l ν) using the Heavy Quark Expansion. (orig.)

  11. A global vertical reference frame based on four regional vertical datums

    Czech Academy of Sciences Publication Activity Database

    Burša, Milan; Kenyon, S.; Kouba, J.; Šíma, Zdislav; Vatrt, V.; Vojtíšková, M.

    2004-01-01

    Roč. 48, č. 3 (2004), s. 493-502 ISSN 0039-3169 Institutional research plan: CEZ:AV0Z1003909 Keywords : geopotentinal * local vertical datums * global vertical reference frame Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.447, year: 2004

  12. Lateral and Vertical Organic Transistors

    Science.gov (United States)

    Al-Shadeedi, Akram

    high doping concentrations. In subsequent chapters, the working mechanisms of OPBTs are discussed. OPBTs consist of two Schottky diodes (top and bottom diode), and the charge transport in these C60-based Schottky diodes is studied first. Two transport regimes can be distinguished in forward direction - injection limited currents (ILCs) and space charge limited currents (SCLCs). It is found that the current increases exponentially with applied voltage in the ILC regime and depends quadratically on the applied voltage in the SCLC regime. Furthermore, it is observed that the forward and backward currents of the Schottky diode are increased by decreasing the C60 layer thickness, increasing the active area, and increasing the temperature. Furthermore, in order to reach a high performance, various treatments have been applied. Air exposure, a variation of the thickness of the top electrode, as well as annealing of the diodes are used to optimize the diodes. OPBTs are processed by using the semiconductor C60 due its high charge carrier mobility and good film-forming properties. Again, the working mechanism of OPBTs is studied by electrical characterization (base-sweep measurements and output characteristics). To achieve a high performance of OPBTs, various treatments and techniques have been applied. The annealing of the OPBTs after fabrication changes the morphology of the base electrode. Thus, openings (pinholes) are formed in the base electrode, which enables a high current transfer from the upper to lower semiconductor layer. The formation of openings is proved by analyzing SEM and TEM image of the base electrode. Adding a doped layer at the emitter is another process to optimize the OPBTs. The doped layer ensures a high charge carrier injection at the emitter, leading to a high transmission and current gain. Furthermore, it has been observed that the ON/OFF ratio and transconductance of OPBTs increases by decreasing their active area. A very high transconductance gm of

  13. Vertical Footbridge Vibrations: The Response Spectrum Methodology

    DEFF Research Database (Denmark)

    Georgakis, Christos; Ingólfsson, Einar Thór

    2008-01-01

    In this paper, a novel, accurate and readily codifiable methodology for the prediction of vertical footbridge response is presented. The methodology is based on the well-established response spectrum approach used in the majority of the world’s current seismic design codes of practice. The concept...... of a universally applicable reference response spectrum is introduced, from which the pedestrian-induced vertical response of any footbridge may be determined, based on a defined “event” and the probability of occurrence of that event. A series of Monte Carlo simulations are undertaken for the development...... period is introduced and its implication on the calculation of footbridge response is discussed. Finally, a brief comparison is made between the theoretically predicted pedestrian-induced vertical response of an 80m long RC footbridge (as an example) and actual field measurements. The comparison shows...

  14. Certified standards and vertical coordination in aquaculture

    DEFF Research Database (Denmark)

    Trifkovic, Neda

    2014-01-01

    This paper explores the interaction between food standards and vertical coordination in the Vietnamese pangasius sector. For farmers and processors alike, the adoption of standards is motivated by a desire to improve market access by ensuring high quality supply. Instead of encouraging the applic......This paper explores the interaction between food standards and vertical coordination in the Vietnamese pangasius sector. For farmers and processors alike, the adoption of standards is motivated by a desire to improve market access by ensuring high quality supply. Instead of encouraging...... the application of standards and contract farming, processing companies prefer to vertically integrate primary production largely due to concerns over the stable supply of pangasius with satisfactory quality and safety attributes. These tendencies increase the market dominance of industrial farming and worsen...

  15. Vertical vibration analysis for elevator compensating sheave

    International Nuclear Information System (INIS)

    Watanabe, Seiji; Nakazawa, Daisuke; Fukui, Daiki; Okawa, Takeya

    2013-01-01

    Most elevators applied to tall buildings include compensating ropes to satisfy the balanced rope tension between the car and the counter weight. The compensating ropes receive tension by the compensating sheave, which is installed at the bottom space of the elevator shaft. The compensating sheave is only suspended by the compensating ropes, therefore, the sheave can move vertically while the car is traveling. This paper shows the elevator dynamic model to evaluate the vertical motion of the compensating sheave. Especially, behavior in emergency cases, such as brake activation and buffer strike, was investigated to evaluate the maximum upward motion of the sheave. The simulation results were validated by experiments and the most influenced factor for the sheave vertical motion was clarified

  16. Plasmonic Properties of Vertically Aligned Nanowire Arrays

    Directory of Open Access Journals (Sweden)

    Hua Qi

    2012-01-01

    Full Text Available Nanowires (NWs/Ag sheath composites were produced to investigate plasmonic coupling between vertically aligned NWs for surface-enhanced Raman scattering (SERS applications. In this investigation, two types of vertical NW arrays were studied; those of ZnO NWs grown on nanosphere lithography patterned sapphire substrate via vapor-liquid-solid (VLS mechanism and Si NW arrays produced by wet chemical etching. Both types of vertical NW arrays were coated with a thin layer of silver by electroless silver plating for SERS enhancement studies. The experimental results show extremely strong SERS signals due to plasmonic coupling between the NWs, which was verified by COMSOL electric field simulations. We also compared the SERS enhancement intensity of aligned and random ZnO NWs, indicating that the aligned NWs show much stronger and repeatable SERS signal than those grown in nonaligned geometries.

  17. Vertical gradients of sunspot magnetic fields

    Science.gov (United States)

    Hagyard, M. J.; Teuber, D.; West, E. A.; Tandberg-Hanssen, E.; Henze, W., Jr.; Beckers, J. M.; Bruner, M.; Hyder, C. L.; Woodgate, B. E.

    1983-01-01

    The results of a Solar Maximum Mission (SMM) guest investigation to determine the vertical gradients of sunspot magnetic fields for the first time from coordinated observations of photospheric and transition-region fields are described. Descriptions are given of both the photospheric vector field of a sunspot, derived from observations using the NASA Marshall Space Flight Center vector magnetograph, and of the line-of-sight component in the transition region, obtained from the SMM Ultraviolet Spectrometer and Polarimeter instrument. On the basis of these data, vertical gradients of the line-of-sight magnetic field component are calculated using three methods. It is found that the vertical gradient of Bz is lower than values from previous studies and that the transition-region field occurs at a height of approximately 4000-6000 km above the photosphere.

  18. Vertical vibration analysis for elevator compensating sheave

    Science.gov (United States)

    Watanabe, Seiji; Okawa, Takeya; Nakazawa, Daisuke; Fukui, Daiki

    2013-07-01

    Most elevators applied to tall buildings include compensating ropes to satisfy the balanced rope tension between the car and the counter weight. The compensating ropes receive tension by the compensating sheave, which is installed at the bottom space of the elevator shaft. The compensating sheave is only suspended by the compensating ropes, therefore, the sheave can move vertically while the car is traveling. This paper shows the elevator dynamic model to evaluate the vertical motion of the compensating sheave. Especially, behavior in emergency cases, such as brake activation and buffer strike, was investigated to evaluate the maximum upward motion of the sheave. The simulation results were validated by experiments and the most influenced factor for the sheave vertical motion was clarified.

  19. Study on characteristics of vertical strong motions

    International Nuclear Information System (INIS)

    Akao, Y.; Katukura, H.; Fukushima, S.; Mizutani, M.

    1993-01-01

    Statistic properties of vertical strong ground motions from near-field earthquakes are discussed in comparison with that of horizontal motions. It is a feature of this analysis that time history of each observed record is divided into direct P- and S-wave segments from a seismological viewpoint. Following results are obtained. Vertical motion energy excited by direct S-waves is about 0.6 times of horizontal ones at deep underground, and it approaches to 1.0 at shallow place. Horizontal motion energy excited by direct P-waves becomes 0.2 times (at deep) or more (at shallow) of vertical one. These results can be available in modeling of input motions for aseismic design. (author)

  20. Control Areas

    Data.gov (United States)

    Department of Homeland Security — This feature class represents electric power Control Areas. Control Areas, also known as Balancing Authority Areas, are controlled by Balancing Authorities, who are...

  1. Vertical stability, high elongation, and the consequences of loss of vertical control on DIII-D

    International Nuclear Information System (INIS)

    Kellman, A.G.; Ferron, J.R.; Jensen, T.H.; Lao, L.L.; Luxon, J.L.; Skinner, D.G.; Strait, E.J.; Reis, E.; Taylor, T.S.; Turnbull, A.D.; Lazarus, E.A.; Lister, J.B.

    1990-09-01

    Recent modifications to the vertical control system for DIII-D has enabled operation of discharges with vertical elongation κ, up to 2.5. When vertical stability is lost, a disruption follows and a large vertical force on the vacuum vessel is observed. The loss of plasma energy begins when the edge safety factor q is 2 but the current decay does not begin until q ∼1.3. Current flow on the open field lines in the plasma scrapeoff layer has been measured and the magnitude and distribution of these currents can explain the observed force on the vessel. Equilibrium calculations and simulation of this vertical displacement episode are presented. 7 refs., 4 figs

  2. Vertically Integrated Multinationals and Productivity Spillovers

    DEFF Research Database (Denmark)

    Clementi, Federico; Bergmann, Friedrich

    are not automatic. In this paper, we study how these externalities are affected by the strategy of vertical integration of foreign multinationals. Our analysis, based on firm-level data of European manufacturing companies, shows that local firms perceive weaker backward spillovers if client foreign affiliates...... are vertically integrated in their industry. The spillovers that arise from the activity of companies that do not invest in the domestic firms’ industry are 2.6 to 5 times stronger than the ones than come from affiliates of multinationals that invest in the industry of local firms....

  3. Thermal Stratification in Vertical Mantle Tanks

    DEFF Research Database (Denmark)

    Knudsen, Søren; Furbo, Simon

    2001-01-01

    It is well known that it is important to have a high degree of thermal stratification in the hot water storage tank to achieve a high thermal performance of SDHW systems. This study is concentrated on thermal stratification in vertical mantle tanks. Experiments based on typical operation conditions...... are carried out to investigate how the thermal stratification is affected by different placements of the mantle inlet. The heat transfer between the solar collector fluid in the mantle and the domestic water in the inner tank is analysed by CFD-simulations. Furthermore, the flow pattern in the vertical mantle...

  4. Breakwaters with Vertical and Inclined Concrete Walls

    DEFF Research Database (Denmark)

    Burcharth, Hans Falk

    Following the PIANC PTC II working group on Analyses of Rubble Mound Breakwaters it was, in 1991, decided to form Working Group (WG) n° 28 on "Breakwaters with vertical and inclined concrete walls" The scope of the work was to achieve a better understanding of the overall safety aspects in the de......Following the PIANC PTC II working group on Analyses of Rubble Mound Breakwaters it was, in 1991, decided to form Working Group (WG) n° 28 on "Breakwaters with vertical and inclined concrete walls" The scope of the work was to achieve a better understanding of the overall safety aspects...

  5. Preserving the Modernist Vertical Urban Factory

    Directory of Open Access Journals (Sweden)

    Nina Rappaport

    2016-07-01

    Full Text Available This essay is adapted in part, from the section, “Modern Factory Architecture” case studies from Nina Rappaport’s book Vertical Urban Factory, published by Actar this spring. Vertical Urban Factory began as an architecture studio, and then an exhibition, which opened in New York in 2011 and traveled to Detroit and Toronto in 2012. Last year the show was displayed at Archizoom at EPFL in Lausanne; Industry City, Brooklyn; and the Charles Moore School of Architecture at Kean University, in New Jersey. The project continues as a think tank evaluating factory futures and urban industrial potential.

  6. Geophysical aspects of vertical streamer seismic data

    Energy Technology Data Exchange (ETDEWEB)

    Sognnes, Walter

    1999-12-31

    Vertical cable acquisition is performed by deploying a certain number of vertical hydrophone arrays in the water column, and subsequently shooting a source point on top of it. The advantage of this particular geometry is that gives a data set with all azimuths included. Therefore a more complete 3-D velocity model can be derived. In this paper there are presented some results from the Fuji survey in the Gulf of Mexico. Based on these results, improved geometries and review recommendations for future surveys are discussed. 7 figs.

  7. Geophysical aspects of vertical streamer seismic data

    Energy Technology Data Exchange (ETDEWEB)

    Sognnes, Walter

    1998-12-31

    Vertical cable acquisition is performed by deploying a certain number of vertical hydrophone arrays in the water column, and subsequently shooting a source point on top of it. The advantage of this particular geometry is that gives a data set with all azimuths included. Therefore a more complete 3-D velocity model can be derived. In this paper there are presented some results from the Fuji survey in the Gulf of Mexico. Based on these results, improved geometries and review recommendations for future surveys are discussed. 7 figs.

  8. Measurement of the CKM matrix element vertical stroke Vts vertical stroke 2

    International Nuclear Information System (INIS)

    Unverdorben, Christopher Gerhard

    2015-03-01

    This is the first direct measurement of the CKM matrix element vertical stroke V ts vertical stroke, using data collected by the ATLAS detector in 2012 at √(s)= 8 TeV pp-collisions with a total integrated luminosity of 20.3 fb -1 . The analysis is based on 112 171 reconstructed t anti t candidate events in the lepton+jets channel, having a purity of 90.0 %. 183 t anti t→W + W - b anti s decays are expected (charge conjugation implied), which are available for the extraction of the CKM matrix element vertical stroke V ts vertical stroke 2 . To identify these rare decays, several observables are examined, such as the properties of jets, tracks and of b-quark identification algorithms. Furthermore, the s-quark hadrons K 0 s are considered, reconstructed by a kinematic fit. The best observables are combined in a multivariate analysis, called ''boosted decision trees''. The responses from Monte Carlo simulations are used as templates for a fit to data events yielding a significance value of 0.7σ for t→s+W decays. An upper limit of vertical stroke V ts vertical stroke 2 <1.74 % at 95 % confidence level is set, including all systematic and statistical uncertainties. So this analysis, using a direct measurement of the CKM matrix element vertical stroke V ts vertical stroke 2 , provides the best direct limit on vertical stroke V ts vertical stroke 2 up to now.

  9. Optimizing the Distribution of Leg Muscles for Vertical Jumping.

    Directory of Open Access Journals (Sweden)

    Jeremy D Wong

    Full Text Available A goal of biomechanics and motor control is to understand the design of the human musculoskeletal system. Here we investigated human functional morphology by making predictions about the muscle volume distribution that is optimal for a specific motor task. We examined a well-studied and relatively simple human movement, vertical jumping. We investigated how high a human could jump if muscle volume were optimized for jumping, and determined how the optimal parameters improve performance. We used a four-link inverted pendulum model of human vertical jumping actuated by Hill-type muscles, that well-approximates skilled human performance. We optimized muscle volume by allowing the cross-sectional area and muscle fiber optimum length to be changed for each muscle, while maintaining constant total muscle volume. We observed, perhaps surprisingly, that the reference model, based on human anthropometric data, is relatively good for vertical jumping; it achieves 90% of the jump height predicted by a model with muscles designed specifically for jumping. Alteration of cross-sectional areas-which determine the maximum force deliverable by the muscles-constitutes the majority of improvement to jump height. The optimal distribution results in large vastus, gastrocnemius and hamstrings muscles that deliver more work, while producing a kinematic pattern essentially identical to the reference model. Work output is increased by removing muscle from rectus femoris, which cannot do work on the skeleton given its moment arm at the hip and the joint excursions during push-off. The gluteus composes a disproportionate amount of muscle volume and jump height is improved by moving it to other muscles. This approach represents a way to test hypotheses about optimal human functional morphology. Future studies may extend this approach to address other morphological questions in ethological tasks such as locomotion, and feature other sets of parameters such as properties of

  10. Vertical profile of fog microphysics : a case study

    Science.gov (United States)

    Burnet, Frédéric; Brilouet, Pierre-Etienne; Mazoyer, Marie; Bourrianne, Thierry; Etcheberry, Jean-Michel; Gaillard, Brigitte; Legain, Dominique; Tzanos, Diane; Barrié, Joel; Barrau, Sébastien; Defoy, Stephan

    2016-04-01

    The occurrence and development of fogs result from the non-linear interaction of competing radiative, thermodynamic, microphysical and dynamical processes and the forecasting of their life cycle still remains a challenging issue. Several field campaigns have been carried out at the SIRTA observatory in the Paris suburb area (France). These experiments have shown that fog events exhibit large differences of the microphysical properties and various evolutions during their life cycle. To better understand relationships between the different processes and to validate numerical simulations it is necessary however to document the vertical profile of the fog microphysics. A CDP (Cloud Droplet Spectrometer) from DMT (Droplet Measurement Technology, Boulder, CO) has been modified to allow measurements of the droplet size distribution in fog layers with a tethered balloon. This instrumental set-up has been used during a field campaign during the winter 2013-214 in the Landes area in the South West of France. To validate the vertical profiles provided by the modified CDP, a mast was equipped with microphysical instruments at 2 altitude levels with an another CDP at 24 m and a Fog Monitor FM100 at 42 m. The instrumental set-up deployed during this campaign is presented. Data collected during a fog event that occurred during the night of 5-6 March 2014 are analysed. We show that microphysical properties such as droplet number concentration, LWC and mean droplet size, exhibit different time evolution during the fog life cycle depending on the altitude level. Droplet size distribution measurements are also investigated. They reveal sharp variations along the vertical close to the top of the fog layer. In addition it is shown that the shape of the size distributions at the top follows a time evolution typical of a quasi-adiabatic droplet growth.

  11. 33 CFR 118.85 - Lights on vertical lift bridges.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on vertical lift bridges... BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.85 Lights on vertical lift bridges. (a) Lift span lights. The vertical lift span of every vertical lift bridge shall be lighted so that the center of the...

  12. Design rules for vertical interconnections by reverse offset printing

    Science.gov (United States)

    Kusaka, Yasuyuki; Kanazawa, Shusuke; Ushijima, Hirobumi

    2018-03-01

    Formation of vertical interconnections by reverse offset printing was investigated, particularly focusing on the transfer step, in which an ink pattern is transferred from a polydimethylsiloxane (PDMS) sheet for the step coverage of contact holes. We systematically examined the coverage of contact holes made of a tapered photoresist layer by varying the hole size, the hole depth, PDMS elasticity, PDMS thickness, printing speed, and printing indentation depth. Successful ink filling was achieved when the PDMS was softer, and the optimal PDMS thickness varied depending on the size of the contact holes. This behaviour is related to the bell-type uplift deformation of incompressible PDMS, which can be described by contact mechanics numerical simulations. Based on direct observation of PDMS/resist-hole contact behaviour, the step coverage of contact holes typically involves two steps of contact area growth: (i) the PDMS first touches the bottom of the holes and then (ii) the contact area gradually and radially widens toward the tapered sidewall. From an engineering perspective, it is pointed out that mechanical synchronisation mismatch in the roll-to-sheet type printing invokes the cracking of ink layers at the edges of contact holes. According to the above design rule, ink filling into a contact hole with thickness of 2.5 µm and radius of 10 µm was achieved. Contact chain patterns with 1386 points of vertical interconnections with the square hole size of up to 10 µm successfully demonstrated the validity of the technique presented herein.

  13. Monitoring Vertical Crustal Deformation and Gravity Variations during Water Level Changes at the Three Gorges Reservoir

    Directory of Open Access Journals (Sweden)

    WANG Wei

    2017-06-01

    Full Text Available Monitoring vertical crustal deformation and gravity changes during water level changes at the Three Gorges reservoir is important for the safe operation of the Three Gorges Dam and for the monitoring and prevention of a regional geological disaster. In this study, we determined vertical crustal deformation and gravity changes during water level variations of the Three Gorges reservoir from direct calculations and actual measurements and a comprehensive solution. We used water areas extracted image data from the ZY-3 satellite and water level data to calculate gravity changes and vertical crustal deformation caused by every 5 m change in the water level due to storage and drainage of the Three Gorges reservoir from 145 m to 175 m. The vertical crustal deformation was up to 30 mm. The location of gravity change above 20 μ Gal(1 Gal=10-2 m/s2 was less than 2 km from the centerline of the Yangtze River. The CORS ES13 in Badong, near the reservoir, measured the vertical crustal deformation during water level changes. Because of the small number of CORS and gravity stations in the Three Gorges reservoir area, monitoring deformation and gravity related to changes in the Three Gorges reservoir water level cannot be closely followed. Using 26 CORS and some of the gravity stations in the Three Gorges area and based on loading deformation and the spherical harmonic analysis method, an integrated solution of vertical deformation and gravity variations during water level changes of the reservoir was determined, which is consistent with the actual CORS monitoring results. By comparison, we found that an integrated solution based on a CORS network can effectively enhance the capability of monitoring vertical crustal deformation and gravity changes during water level variations of the reservoir.

  14. Vortex capturing vertical axis wind turbine

    International Nuclear Information System (INIS)

    Zannetti, L; Gallizio, F; Ottino, G

    2007-01-01

    An analytical-numerical study is presented for an innovative lift vertical axis turbine whose blades are designed with vortex trapping cavities that act as passive flow control devices. The unsteady flow field past one-bladed and two-bladed turbines is described by a combined analytical and numerical method based on conformal mapping and on a blob vortex method

  15. Digital Microfluidic System with Vertical Functionality

    Directory of Open Access Journals (Sweden)

    Brian F. Bender

    2015-11-01

    Full Text Available Digital (droplet microfluidics (DµF is a powerful platform for automated lab-on-a-chip procedures, ranging from quantitative bioassays such as RT-qPCR to complete mammalian cell culturing. The simple MEMS processing protocols typically employed to fabricate DµF devices limit their functionality to two dimensions, and hence constrain the applications for which these devices can be used. This paper describes the integration of vertical functionality into a DµF platform by stacking two planar digital microfluidic devices, altering the electrode fabrication process, and incorporating channels for reversibly translating droplets between layers. Vertical droplet movement was modeled to advance the device design, and three applications that were previously unachievable using a conventional format are demonstrated: (1 solutions of calcium dichloride and sodium alginate were vertically mixed to produce a hydrogel with a radially symmetric gradient in crosslink density; (2 a calcium alginate hydrogel was formed within the through-well to create a particle sieve for filtering suspensions passed from one layer to the next; and (3 a cell spheroid formed using an on-chip hanging-drop was retrieved for use in downstream processing. The general capability of vertically delivering droplets between multiple stacked levels represents a processing innovation that increases DµF functionality and has many potential applications.

  16. Vertical retorts for distilling, carbonizing, roasting, etc

    Energy Technology Data Exchange (ETDEWEB)

    Walker, H R.L.; Bates, W R

    1917-11-17

    In a continuously operated vertical retort for destructive distillation or roasting the combination of an annular internally and externally heated construction with an annular plunger adapted to compress and assist the travel of the charge and to aid in discharging material substantially is described.

  17. The Design Philosophy for a Vertical Breakwater

    DEFF Research Database (Denmark)

    Vrijling, J. K.; Burcharth, H. F.; Voortman, H. G.

    2000-01-01

    A consistent risk-based design philosophy for vertical breakwaters is proposed. The design philosophy consists of a two-step approach. The first step is the definition of the main function of the breakwater, which leads to a definition of failure. The second step is the choice of the acceptable...

  18. Determinants Of Vertical And Horizontal Export Diversification ...

    African Journals Online (AJOL)

    The study also reveals domestic investment plays an important role to enhance vertical as well as horizontal export diversification for East Asia, while it only ... resource-based industries and gradually shift production and exports from customary products to more dynamic ones by developing competitive advantage in the ...

  19. A Comparison of Methods of Vertical Equating.

    Science.gov (United States)

    Loyd, Brenda H.; Hoover, H. D.

    Rasch model vertical equating procedures were applied to three mathematics computation tests for grades six, seven, and eight. Each level of the test was composed of 45 items in three sets of 15 items, arranged in such a way that tests for adjacent grades had two sets (30 items) in common, and the sixth and eighth grades had 15 items in common. In…

  20. Vertical reflector for bifacial PV-panels

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Thorsteinsson, Sune; Poulsen, Peter Behrensdorff

    2016-01-01

    Bifacial solar modules offer an interesting price/performance ratio, and much work has been focused on directing the ground albedo to the back of the solar cells. In this work we design and develop a reflector for a vertical bifacial panel, with the objective to optimize the energy harvest...

  1. On production costs in vertical differentiation models

    OpenAIRE

    Dorothée Brécard

    2009-01-01

    In this paper, we analyse the effects of the introduction of a unit production cost beside a fixed cost of quality improvement in a duopoly model of vertical product differentiation. Thanks to an original methodology, we show that a low unit cost tends to reduce product differentiation and thus prices, whereas a high unit cost leads to widen product differentiation and to increase prices

  2. MHD stability of vertically asymmetric tokamak equilibria

    International Nuclear Information System (INIS)

    Dalhed, H.E.; Grimm, R.C.; Johnson, J.L.

    1981-03-01

    The ideal MHD stability properties of a special class of vertically asymmetric tokamak equilibria are examined. The calculations confirm that no major new physical effects are introduced and the modifications can be understood by conventional arguments. The results indicate that significant departures from up-down symmetry can be tolerated before the reduction in β becomes important for reactor operation

  3. Optical anisotropy in vertically coupled quantum dots

    DEFF Research Database (Denmark)

    Yu, Ping; Langbein, Wolfgang Werner; Leosson, Kristjan

    1999-01-01

    We have studied the polarization of surface and edge-emitted photoluminescence (PL) from structures with vertically coupled In0.5Ga0.5As/GaAs quantum dots (QD's) grown by molecular beam epitaxy. The PL polarization is found to be strongly dependent on the number of stacked layers. While single...... number due to increasing dot size....

  4. Transient well flow in vertically heterogeneous aquifers.

    NARCIS (Netherlands)

    Hemker, C.J.

    1999-01-01

    A solution for the general problem of computing well flow in vertically heterogeneous aquifers is found by an integration of both analytical and numerical techniques. The radial component of flow is treated analytically; the drawdown is a continuous function of the distance to the well. The

  5. Proverbs : Probabilistic design tools for vertical breakwaters

    NARCIS (Netherlands)

    Oumeraci, H.; Allsop, N.W.H.; De Groot, M.B.; Crouch, R.S.; Vrijling, J.K.

    1999-01-01

    Final report and appendices of the European project Proverbs on tools for the design of vertical breakwaters (caisson type breakwaters) and similar hydraulic structures in the coastal zone. It includes the loads (waves) as well as the strength of the structure (geotechnial aspects, structural

  6. The capillary interaction between two vertical cylinders

    KAUST Repository

    Cooray, Himantha; Cicuta, Pietro; Vella, Dominic

    2012-01-01

    surface clusters. Here we present a numerical method for determining the three-dimensional meniscus around a pair of vertical circular cylinders. This involves the numerical solution of the fully nonlinear Laplace-Young equation using a mesh-free finite

  7. Manufacturing: the new case for vertical integration

    NARCIS (Netherlands)

    Kumpe, Ted; Bolwijn, Piet

    1988-01-01

    The article argues that the solid corporation will continue to view vertical integration as a critical part of manufacturing reform. Manufacturing reform and backward integration are related in insidious ways to the three stages of production over which the big manufacturers preside. Without

  8. Vertical integration as organizational strategy formation

    NARCIS (Netherlands)

    Romme, A.G.L.

    1990-01-01

    This paper contributes to research into the strategy—environment relationship, especially looking at the issue of vertical integration. It aims at a synthesis of process and content approaches to strategic change on the level of the organization’s dominant group. The key factor is uncertainty, which

  9. Vertical Integration: Teachers' Knowledge and Teachers' Voice.

    Science.gov (United States)

    Corrie, L.

    1995-01-01

    Traces the theoretical basis for vertical integration in early school years. Contrasts transmission-based pedagogy with a higher level of teacher control, and acquirer-based pedagogy with a higher level of student control. Suggests that early childhood pedagogy will be maintained when teachers are able to articulate their pedagogical knowledge and…

  10. Vertical integration of HRD policy within companies

    NARCIS (Netherlands)

    Wognum, Ida

    2001-01-01

    This study concerns HRD policy making in companies. More specifically, it explores whether so-called vertical integration of HRD policy at different organizational levels occurs within companies. The study involved forty-four large companies in the industrial and the financial and commercial

  11. A note on partial vertical integration

    NARCIS (Netherlands)

    G.W.J. Hendrikse (George); H.J.M. Peters (Hans)

    1989-01-01

    textabstractA simple model is constructed to show how partial vertical integration may emerge as an equilibrium market structure in a world characterized by rationing, differences in the reservation prices of buyers, and in the risk attitudes of buyers and sellers. The buyers with the high

  12. Vertical Integration Spurs American Health Care Revolution.

    Science.gov (United States)

    Phillips, Richard C.

    1986-01-01

    Under new "managed health care systems," the classical functional separation of risk taker, claims payor, and provider are vertically integrated into a common entity. This evolution should produce a competitive environment with medical care rendered to all Americans on a more cost-effective basis. (CJH)

  13. Oblique patterned etching of vertical silicon sidewalls

    Science.gov (United States)

    Bruce Burckel, D.; Finnegan, Patrick S.; David Henry, M.; Resnick, Paul J.; Jarecki, Robert L.

    2016-04-01

    A method for patterning on vertical silicon surfaces in high aspect ratio silicon topography is presented. A Faraday cage is used to direct energetic reactive ions obliquely through a patterned suspended membrane positioned over the topography. The technique is capable of forming high-fidelity pattern (100 nm) features, adding an additional fabrication capability to standard top-down fabrication approaches.

  14. Vertical Dynamic Stiffness of Offshore Foundations

    DEFF Research Database (Denmark)

    Latini, Chiara; Cisternino, Michele; Zania, Varvara

    2016-01-01

    Nowadays, pile and suction caisson foundations are widely used to support offshore structures which are subjected to vertical dynamic loads. The dynamic soil-structure interaction of floating foundations (foundations embedded in a soil layer whose height is greater than the foundation length) is ...

  15. Vertical pump with free floating check valve

    International Nuclear Information System (INIS)

    Lindsay, M.

    1980-01-01

    A vertical pump is described which has a bottom discharge with a free floating check valve disposed in the outlet plenum thereof. The free floating check valve comprises a spherical member with a hemispherical cage-like member attached thereto which is capable of allowing forward or reverse flow under appropriate conditions while preventing reverse flow under inappropriate conditions

  16. Vertical field and equilibrium calculation in ETE

    International Nuclear Information System (INIS)

    Montes, Antonio; Shibata, Carlos Shinya.

    1996-01-01

    The free-boundary MHD equilibrium code HEQ is used to study the plasma behaviour in the tokamak ETE, with optimized compensations coils and vertical field coils. The changes on the equilibrium parameters for different plasma current values are also investigated. (author). 5 refs., 4 figs., 2 tabs

  17. Rover's Wheel Churns Up Bright Martian Soil (Vertical)

    Science.gov (United States)

    2009-01-01

    NASA's Mars Exploration Rover Spirit acquired this mosaic on the mission's 1,202nd Martian day, or sol (May 21, 2007), while investigating the area east of the elevated plateau known as 'Home Plate' in the 'Columbia Hills.' The mosaic shows an area of disturbed soil, nicknamed 'Gertrude Weise' by scientists, made by Spirit's stuck right front wheel. The trench exposed a patch of nearly pure silica, with the composition of opal. It could have come from either a hot-spring environment or an environment called a fumarole, in which acidic, volcanic steam rises through cracks. Either way, its formation involved water, and on Earth, both of these types of settings teem with microbial life. The image is presented here as a vertical projection, as if looking straight down, and in false color, which brings out subtle color differences.

  18. 3D correlation imaging of the vertical gradient of gravity data

    International Nuclear Information System (INIS)

    Guo, Lianghui; Meng, Xiaohong; Shi, Lei

    2011-01-01

    We present a new 3D correlation imaging approach for vertical gradient of gravity data for deriving a 3D equivalent mass distribution in the subsurface. In this approach, we divide the subsurface space into a 3D regular grid, and then at each grid node calculate a cross correlation between the vertical gradient of the observed gravity data and the theoretical gravity vertical gradient due to a point mass source. The resultant correlation coefficients are used to describe the equivalent mass distribution in a probability sense. We simulate a geological syncline model intruded by a dike and later broken by two vertical faults. The vertical gradient of gravity anomaly of the model is calculated and used to test the approach. The results demonstrate that the equivalent mass distribution derived by the approach reflects the basic geological structures of the model. We also test the approach on the transformed vertical gradient of real Bouguer gravity data from a geothermal survey area in Northern China. The thermal reservoirs are located in the lower portion of the sedimentary basin. From the resultant equivalent mass distribution, we produce the depth distribution of the bottom interface of the basin and predict possible hidden faults present in the basin

  19. Modeling tides and vertical tidal mixing: A reality check

    International Nuclear Information System (INIS)

    Robertson, Robin

    2010-01-01

    Recently, there has been a great interest in the tidal contribution to vertical mixing in the ocean. In models, vertical mixing is estimated using parameterization of the sub-grid scale processes. Estimates of the vertical mixing varied widely depending on which vertical mixing parameterization was used. This study investigated the performance of ten different vertical mixing parameterizations in a terrain-following ocean model when simulating internal tides. The vertical mixing parameterization was found to have minor effects on the velocity fields at the tidal frequencies, but large effects on the estimates of vertical diffusivity of temperature. Although there was no definitive best performer for the vertical mixing parameterization, several parameterizations were eliminated based on comparison of the vertical diffusivity estimates with observations. The best performers were the new generic coefficients for the generic length scale schemes and Mellor-Yamada's 2.5 level closure scheme.

  20. Vertical Structure of Radiation-pressure-dominated Thin Disks: Link between Vertical Advection and Convective Stability

    International Nuclear Information System (INIS)

    Gong, Hong-Yu; Gu, Wei-Min

    2017-01-01

    In the classic picture of standard thin accretion disks, viscous heating is balanced by radiative cooling through the diffusion process, and the radiation-pressure-dominated inner disk suffers convective instability. However, recent simulations have shown that, owing to the magnetic buoyancy, the vertical advection process can significantly contribute to energy transport. In addition, in comparing the simulation results with the local convective stability criterion, no convective instability has been found. In this work, following on from simulations, we revisit the vertical structure of radiation-pressure-dominated thin disks and include the vertical advection process. Our study indicates a link between the additional energy transport and the convectively stable property. Thus, the vertical advection not only significantly contributes to the energy transport, but it also plays an important role in making the disk convectively stable. Our analyses may help to explain the discrepancy between classic theory and simulations on standard thin disks.

  1. vertical bar Vub vertical bar from exclusive semileptonic B→π decays

    International Nuclear Information System (INIS)

    Flynn, Jonathan M.; Nieves, Juan

    2007-01-01

    We use Omnes representations of the form factors f + and f 0 for exclusive semileptonic B→π decays, paying special attention to the treatment of the B* pole and its effect on f + . We apply them to combine experimental partial branching fraction information with theoretical calculations of both form factors to extract vertical bar V ub vertical bar. The precision we achieve is competitive with the inclusive determination and we do not find a significant discrepancy between our result, vertical bar V ub vertical bar=(3.90+/-0.32+/-0.18)x10 -3 , and the inclusive world average value (4.45+/-0.20+/-0.26)x10 -3 [Heavy Flavor Averaging Group (HFAG), hep-ex/0603003

  2. INNOVATION DEVELOPMENT MANAGEMENT IN VERTICALLY INTEGRATED HOLDING COMPANY

    Directory of Open Access Journals (Sweden)

    Natalya T. Uspenskaja

    2015-01-01

    Full Text Available The trend towards production consolidation and integration processes taking place both in the Russian and global economies leads to development of business associations, with a holding company being the most common form inRussiaand around the globe. The evidence in favor of the formation of holding companies is that they can benefit from the scale (bulk purchasing, centralized stuff training; in the global capital and exports markets they can be more effective than smaller businesses and, if non-profitable, a loss-making structure is easier to liquidate than the entire company; holding companies and associations can be an effective defender from political interference. As the importance of the well-functioning and harmonized procedure for the companies’ integration will increase (especially in the context of Russian business, where specific features of many areas of the production system imply the use of holding oligopolies as the most effective form of market structures, there is a need in their more profound study and, in particular, in the analysis of the most important technologies of the general integration procedure. The article outlines the relevance of innovative development management of vertically integrated holding systems, lists principles of innovative activity management and considers the features of innovation management of a vertically integrated holding company. The objective of the research is to study theoretical and practical aspects of innovative development management in vertically integrated holding systems. The object of research is management structures in innovative holding companies. While working on the article, the following methods of economic research were used: abstract and logical method, empirical method, method of expert evaluations, as well as methods of structural and functional and statistical analysis. 

  3. Device for passive flow control around vertical axis marine turbine

    Science.gov (United States)

    Coşoiu, C. I.; Georgescu, A. M.; Degeratu, M.; Haşegan, L.; Hlevca, D.

    2012-11-01

    The power supplied by a turbine with the rotor placed in a free stream flow may be increased by augmenting the velocity in the rotor area. The energy of the free flow is dispersed and it may be concentrated by placing a profiled structure around the bare turbine in order to concentrate more energy in the rotor zone. At the Aerodynamic and Wind Engineering Laboratory (LAIV) of the Technical University of Civil Engineering of Bucharest (UTCB) it was developed a concentrating housing to be used for hydro or aeolian horizontal axis wind turbines, in order to increase the available energy in the active section of turbine rotor. The shape of the concentrating housing results by superposing several aero/hydro dynamic effects, the most important being the one generated by the passive flow control devices that were included in the housing structure. Those concentrating housings may be also adapted for hydro or aeolian turbines with vertical axis. The present paper details the numerical research effectuated at the LAIV to determine the performances of a vertical axis marine turbine equipped with such a concentrating device, in order to increase the energy quantity extracted from the main flow. The turbine is a Darrieus type one with three vertical straight blades, symmetric with respect to the axis of rotation, generated using a NACA4518 airfoil. The global performances of the turbine equipped with the concentrating housing were compared to the same characteristics of the bare turbine. In order to validate the numerical approach used in this paper, test cases from the literature resulting from experimental and numerical simulations for similar situations, were used.

  4. Device for passive flow control around vertical axis marine turbine

    International Nuclear Information System (INIS)

    Coşoiu, C I; Georgescu, A M; Degeratu, M; Haşegan, L; Hlevca, D

    2012-01-01

    The power supplied by a turbine with the rotor placed in a free stream flow may be increased by augmenting the velocity in the rotor area. The energy of the free flow is dispersed and it may be concentrated by placing a profiled structure around the bare turbine in order to concentrate more energy in the rotor zone. At the Aerodynamic and Wind Engineering Laboratory (LAIV) of the Technical University of Civil Engineering of Bucharest (UTCB) it was developed a concentrating housing to be used for hydro or aeolian horizontal axis wind turbines, in order to increase the available energy in the active section of turbine rotor. The shape of the concentrating housing results by superposing several aero/hydro dynamic effects, the most important being the one generated by the passive flow control devices that were included in the housing structure. Those concentrating housings may be also adapted for hydro or aeolian turbines with vertical axis. The present paper details the numerical research effectuated at the LAIV to determine the performances of a vertical axis marine turbine equipped with such a concentrating device, in order to increase the energy quantity extracted from the main flow. The turbine is a Darrieus type one with three vertical straight blades, symmetric with respect to the axis of rotation, generated using a NACA4518 airfoil. The global performances of the turbine equipped with the concentrating housing were compared to the same characteristics of the bare turbine. In order to validate the numerical approach used in this paper, test cases from the literature resulting from experimental and numerical simulations for similar situations, were used.

  5. Optimizing the Distribution of Leg Muscles for Vertical Jumping

    Science.gov (United States)

    Wong, Jeremy D.; Bobbert, Maarten F.; van Soest, Arthur J.; Gribble, Paul L.; Kistemaker, Dinant A.

    2016-01-01

    A goal of biomechanics and motor control is to understand the design of the human musculoskeletal system. Here we investigated human functional morphology by making predictions about the muscle volume distribution that is optimal for a specific motor task. We examined a well-studied and relatively simple human movement, vertical jumping. We investigated how high a human could jump if muscle volume were optimized for jumping, and determined how the optimal parameters improve performance. We used a four-link inverted pendulum model of human vertical jumping actuated by Hill-type muscles, that well-approximates skilled human performance. We optimized muscle volume by allowing the cross-sectional area and muscle fiber optimum length to be changed for each muscle, while maintaining constant total muscle volume. We observed, perhaps surprisingly, that the reference model, based on human anthropometric data, is relatively good for vertical jumping; it achieves 90% of the jump height predicted by a model with muscles designed specifically for jumping. Alteration of cross-sectional areas—which determine the maximum force deliverable by the muscles—constitutes the majority of improvement to jump height. The optimal distribution results in large vastus, gastrocnemius and hamstrings muscles that deliver more work, while producing a kinematic pattern essentially identical to the reference model. Work output is increased by removing muscle from rectus femoris, which cannot do work on the skeleton given its moment arm at the hip and the joint excursions during push-off. The gluteus composes a disproportionate amount of muscle volume and jump height is improved by moving it to other muscles. This approach represents a way to test hypotheses about optimal human functional morphology. Future studies may extend this approach to address other morphological questions in ethological tasks such as locomotion, and feature other sets of parameters such as properties of the skeletal

  6. Static loading and vertical displacement at southern Siberia

    Directory of Open Access Journals (Sweden)

    Anton V. Timofeev

    2017-05-01

    Full Text Available Seismic method is usually used for elastic parametric estimation. This is why this method presents dynamic parameters of Earth. Frequency seismic range changes greatly from geodynamic modelling time. Now we have opportunity to use geodesy result for some years for elastic parameters estimation. Static solution from elastic theory may be used for the interpretation of long term results. It presents static elastic parameter. The inverse problem for different types of vertical surface loading on one year period is calculated. Two cases of loading with maximal and minimal area are presented. Results are determined by space geodesy and leveling methods. Current relation between atmospheric pressure and vertical displacements was estimated at the center of Siberian Anti Cyclone with size varied from 2000 km to 3000 km. Pressure-displacement coefficients (PDC can be achieved by three years observation (0.997 mm/mbar for NVSK GPS station. It is used for elastic module study of geology medium with maximum thickness up to 600 km. In the context of elastic model, the modulus of rigidity is estimated to be 113 GPa. Vast expanse of anti-cyclone may relate with rheology of crust and upper mantle. Smaller size of surface loading – local loading is seasonal variation of water reservoir. Annual vertical changes were obtained by leveling near the dam of the reservoir. PDC ratio was 1.15 mm/bar for these places. In elastic theory, the Young modulus E = 80 GPa (Poisson ratio = 0.25, the modulus of rigidity = 32 GPa was calculated by sixteen years of leveling measurements. This result can effectively be represented for upper crust. Our results were checked by solution for coseismic displacement of Chyia-Altai earthquake (Sep. 27, 2003, M = 7.3. Coseismic results calculated by static modules agree with experimental coseismic GPS data at 10% level.

  7. Impact of Vertical Canopy Position on Leaf Spectral Properties and Traits across Multiple Species

    Directory of Open Access Journals (Sweden)

    Tawanda W. Gara

    2018-02-01

    Full Text Available Understanding the vertical pattern of leaf traits across plant canopies provide critical information on plant physiology, ecosystem functioning and structure and vegetation response to climate change. However, the impact of vertical canopy position on leaf spectral properties and subsequently leaf traits across the entire spectrum for multiple species is poorly understood. In this study, we examined the ability of leaf optical properties to track variability in leaf traits across the vertical canopy profile using Partial Least Square Discriminatory Analysis (PLS-DA. Leaf spectral measurements together with leaf traits (nitrogen, carbon, chlorophyll, equivalent water thickness and specific leaf area were studied at three vertical canopy positions along the plant stem: lower, middle and upper. We observed that foliar nitrogen (N, chlorophyll (Cab, carbon (C, and equivalent water thickness (EWT were higher in the upper canopy leaves compared with lower shaded leaves, while specific leaf area (SLA increased from upper to lower canopy leaves. We found that leaf spectral reflectance significantly (P ≤ 0.05 shifted to longer wavelengths in the ‘red edge’ spectrum (685–701 nm in the order of lower > middle > upper for the pooled dataset. We report that spectral bands that are influential in the discrimination of leaf samples into the three groups of canopy position, based on the PLS-DA variable importance projection (VIP score, match with wavelength regions of foliar traits observed to vary across the canopy vertical profile. This observation demonstrated that both leaf traits and leaf reflectance co-vary across the vertical canopy profile in multiple species. We conclude that canopy vertical position has a significant impact on leaf spectral properties of an individual plant’s traits, and this finding holds for multiple species. These findings have important implications on field sampling protocols, upscaling leaf traits to canopy level

  8. Adaptation of the vertical vestibulo-ocular reflex in cats during low-frequency vertical rotation.

    Science.gov (United States)

    Fushiki, Hiroaki; Maruyama, Motoyoshi; Shojaku, Hideo

    2018-04-01

    We examined plastic changes in the vestibulo-ocular reflex (VOR) during low-frequency vertical head rotation, a condition under which otolith inputs from the vestibular system are essential for VOR generation. For adaptive conditioning of the vertical VOR, 0.02Hz sinusoidal pitch rotation for one hour about the earth's horizontal axis was synchronized with out-of-phase vertical visual stimulation from a random dot pattern. A vertical VOR was well evoked when the upright animal rotated around the earth-horizontal axis (EHA) at low frequency due to the changing gravity stimulus and dynamic stimulation of the otoliths. After adaptive conditioning, the amplitude of the vertical VOR increased by an average of 32.1%. Our observations showing plasticity in the otolithic contribution to the VOR may provide a new strategy for visual-vestibular mismatch training in patients with otolithic disorders. This low-frequency vertical head rotation protocol also provides a model for investigating the mechanisms underlying the adaptation of VORs mediated by otolith activation. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Evaluation of vertical coordinate and vertical mixing algorithms in the HYbrid-Coordinate Ocean Model (HYCOM)

    Science.gov (United States)

    Halliwell, George R.

    Vertical coordinate and vertical mixing algorithms included in the HYbrid Coordinate Ocean Model (HYCOM) are evaluated in low-resolution climatological simulations of the Atlantic Ocean. The hybrid vertical coordinates are isopycnic in the deep ocean interior, but smoothly transition to level (pressure) coordinates near the ocean surface, to sigma coordinates in shallow water regions, and back again to level coordinates in very shallow water. By comparing simulations to climatology, the best model performance is realized using hybrid coordinates in conjunction with one of the three available differential vertical mixing models: the nonlocal K-Profile Parameterization, the NASA GISS level 2 turbulence closure, and the Mellor-Yamada level 2.5 turbulence closure. Good performance is also achieved using the quasi-slab Price-Weller-Pinkel dynamical instability model. Differences among these simulations are too small relative to other errors and biases to identify the "best" vertical mixing model for low-resolution climate simulations. Model performance deteriorates slightly when the Kraus-Turner slab mixed layer model is used with hybrid coordinates. This deterioration is smallest when solar radiation penetrates beneath the mixed layer and when shear instability mixing is included. A simulation performed using isopycnic coordinates to emulate the Miami Isopycnic Coordinate Ocean Model (MICOM), which uses Kraus-Turner mixing without penetrating shortwave radiation and shear instability mixing, demonstrates that the advantages of switching from isopycnic to hybrid coordinates and including more sophisticated turbulence closures outweigh the negative numerical effects of maintaining hybrid vertical coordinates.

  10. Microstructure, vertical strain control and tunable functionalities in self-assembled, vertically aligned nanocomposite thin films

    International Nuclear Information System (INIS)

    Chen, Aiping; Bi, Zhenxing; Jia, Quanxi; MacManus-Driscoll, Judith L.; Wang, Haiyan

    2013-01-01

    Vertically aligned nanocomposite (VAN) oxide thin films have recently stimulated a significant amount of research interest owing to their novel architecture, vertical interfacial strain control and tunable material functionalities. In this work, the growth mechanisms of VAN thin films have been investigated by varying the composite material system, the ratio of the two constituent phases, and the thin film growth conditions including deposition temperature and oxygen pressure as well as growth rate. It has been shown that thermodynamic parameters, elastic and interfacial energies and the multiple phase ratio play dominant roles in the resulting microstructure. In addition, vertical interfacial strain has been observed in BiFeO 3 (BFO)- and La 0.7 Sr 0.3 MnO 3 (LSMO)-based VAN thin film systems; the vertical strain could be tuned by the growth parameters and selection of a suitable secondary phase. The tunability of physical properties such as dielectric loss in BFO:Sm 2 O 3 VAN and low-field magnetoresistance in LSMO-based VAN systems has been demonstrated. The enhancement and tunability of those physical properties have been attributed to the unique VAN architecture and vertical strain control. These results suggest that VAN architecture with novel microstructure and unique vertical strain tuning could provide a general route for tailoring and manipulating the functionalities of oxide thin films

  11. In vivo microvascular imaging of human oral and nasal cavities using swept-source optical coherence tomography with a single forward/side viewing probe

    Science.gov (United States)

    Choi, Woo June; Wang, Ruikang K.

    2015-03-01

    We report three-dimensional (3D) imaging of microcirculation within human cavity tissues in vivo using a high-speed swept-source optical coherence tomography (SS-OCT) at 1.3 μm with a modified probe interface. Volumetric structural OCT images of the inner tissues of oral and nasal cavities are acquired with a field of view of 2 mm x 2 mm. Two types of disposable and detachable probe attachments are devised and applied to the port of the imaging probe of OCT system, enabling forward and side imaging scans for selective and easy access to specific cavity tissue sites. Blood perfusion is mapped with OCT-based microangiography from 3D structural OCT images, in which a novel vessel extraction algorithm is used to decouple dynamic light scattering signals, due to moving blood cells, from the background scattering signals due to static tissue elements. Characteristic tissue anatomy and microvessel architectures of various cavity tissue regions of a healthy human volunteer are identified with the 3D OCT images and the corresponding 3D vascular perfusion maps at a level approaching capillary resolution. The initial finding suggests that the proposed method may be engineered into a promising tool for evaluating and monitoring tissue microcirculation and its alteration within a wide-range of cavity tissues in the patients with various pathological conditions.

  12. In vivo layer visualization of rat olfactory bulb by a swept source optical coherence tomography and its confirmation through electrocoagulation and anatomy

    Science.gov (United States)

    Watanabe, Hideyuki; Rajagopalan, Uma Maheswari; Nakamichi, Yu; Igarashi, Kei M.; Madjarova, Violeta Dimitrova; Kadono, Hirofumi; Tanifuji, Manabu

    2011-01-01

    Here, we report in vivo 3-D visualization of the layered organization of a rat olfactory bulb (OB) by a swept source optical coherence tomography (SS-OCT). The SS-OCT operates at a wavelength of 1334 nm with respective theoretical depth and lateral resolutions of 6.7 μm and 15.4 μm in air and hence it is possible to get a 3D structural map of OB in vivo at the micron level resolution with millimeter-scale imaging depth. Up until now, with methods such as MRI, confocal microscopy, OB depth structure in vivo had not been clearly visualized as these do not satisfy the criterion of simultaneously providing micron-scale spatial resolution and imaging up to a few millimeter in depth. In order to confirm the OB’s layered organization revealed by SS-OCT, we introduced the technique of electrocoagulation to make landmarks across the layered structure. To our knowledge this is such a first study that combines electrocoagulation and OCT in vivo of rat OB. Our results confirmed the layered organization of OB, and moreover the layers were clearly identified by electrocoagulation landmarks both in the OCT structural and anatomical slice images. We expect such a combined study is beneficial for both OCT and neuroscience fields. PMID:21833364

  13. Investigation of firing temperature variation in ovens for ceramic-fused-to-metal dental prostheses using swept source optical coherence tomography

    Science.gov (United States)

    Todor, Raluca; Negrutiu, Meda-Lavinia; Sinescu, Cosmin; Topala, Florin Ionel; Bradu, Adrian; Duma, Virgil-Florin; Romînu, Mihai; Podoleanu, Adrian G.

    2018-03-01

    One of the most common fabrication techniques for dental ceramics is sintering, a process of heating of the ceramic to ensure densification. This occurs by viscous flow when the firing temperature is reached. Acceptable restorations require the alloy and ceramic to be chemically, thermally, mechanically, and aesthetically compatible. Thermal and mechanical compatibility include a fusing temperature of ceramic that does not cause distortion of the metal substructure. Decalibration of ovens used for firing of the ceramic layers for metal ceramic dental prostheses leads to stress and cracks in the veneering material, and ultimately to the failure of the restoration. 25 metal ceramic prostheses were made for this study. They were divided in five groups, each sintered at a different temperature: a group at the temperature prescribed by the producer, two groups at lower and two groups at higher temperatures set in the ceramic oven. An established noninvasive biomedical imaging method, swept source (SS) optical coherence tomography (OCT) was employed, in order to evaluate the modifications induced when using temperatures different from those prescribed for firing the samples. A quantitative assessment of the probes is performed by en-face OCT images, taken at constant depths inside the samples. The differences in granulation, thus in reflectivity allow for extracting rules-of-thumb to evaluate fast, by using only the prostheses currently produced the current calibration of the ceramic oven. OCT imaging can allow quick identification of the oven decalibration, to avoid producing dental prostheses with defects.

  14. Silicon photonic integrated circuit swept-source optical coherence tomography receiver with dual polarization, dual balanced, in-phase and quadrature detection.

    Science.gov (United States)

    Wang, Zhao; Lee, Hsiang-Chieh; Vermeulen, Diedrik; Chen, Long; Nielsen, Torben; Park, Seo Yeon; Ghaemi, Allan; Swanson, Eric; Doerr, Chris; Fujimoto, James

    2015-07-01

    Optical coherence tomography (OCT) is a widely used three-dimensional (3D) optical imaging method with many biomedical and non-medical applications. Miniaturization, cost reduction, and increased functionality of OCT systems will be critical for future emerging clinical applications. We present a silicon photonic integrated circuit swept-source OCT (SS-OCT) coherent receiver with dual polarization, dual balanced, in-phase and quadrature (IQ) detection. We demonstrate multiple functional capabilities of IQ polarization resolved detection including: complex-conjugate suppressed full-range OCT, polarization diversity detection, and polarization-sensitive OCT. To our knowledge, this is the first demonstration of a silicon photonic integrated receiver for OCT. The integrated coherent receiver provides a miniaturized, low-cost solution for SS-OCT, and is also a key step towards a fully integrated high speed SS-OCT system with good performance and multi-functional capabilities. With further performance improvement and cost reduction, photonic integrated technology promises to greatly increase penetration of OCT systems in existing applications and enable new applications.

  15. The effect of vertical earthquake component on the uplift of the nuclear reactor building

    International Nuclear Information System (INIS)

    Kobayashi, Toshio

    1986-01-01

    During a strong earthquake, the base mat of a nuclear reactor building may be lifted partially by the response overturning moment. And it causes geometrical nonlinear interaction between the base mat and rock foundation beneath it. In order to avoid this uplift phenomena, the base mat and/or plan of the building is enlarged in some cases. These special design need more cost and/or time in construction. In the evaluation of the uplift phenomena, a parameter ''η'' named ''contact ratio'' is used defined as the ratio of compression stress zone area of base mat for total area of base mat. Usually this contact ratio is calculated under the combination of the maximum overturning moment obtained by the linear earthquake response analysis and the normal force by the gravity considering the effect of the vertical earthquake component. In this report, the effect of vertical earthquake component for the uplift phenomena is studied and it concludes that the vertical earthquake component gives little influence on the contact ratio. In order to obtain more reasonable contact retio, the nonlinear rocking analysis subjected to horizontal and vertical earthquake motions simultaneously is proposed in this report. As the second best method, the combination of the maximum overturning moment obtained by linear analysis and the normal force by only the gravity without the vertical earthquake effect is proposed. (author)

  16. Vertical nanowire arrays as a versatile platform for protein detection and analysis

    DEFF Research Database (Denmark)

    Rostgaard, Katrine R.; Frederiksen, Rune S.; Liu, Yi-Chi

    2013-01-01

    solutions. Here we show that vertical arrays of nanowires (NWs) can overcome several bottlenecks of using nanoarrays for extraction and analysis of proteins. The high aspect ratio of the NWs results in a large surface area available for protein immobilization and renders passivation of the surface between...

  17. One Year of Vertical Wind Profiles Measurements at a Mediterranean Coastal Site of South Italy

    DEFF Research Database (Denmark)

    Calidonna, Claudia Roberta; Gullì, Daniel; Avolio, Elenio

    2015-01-01

    To exploit wind energy both onshore and offshore in coastal area the effect of the coastal discontinuity is important. The shape of the vertical wind profiles and the related c parameter of the Weibull distribution are impacted by the atmospheric internal boundary layers developing from the coast...

  18. Increase of electrodeposited catalyst stability via plasma grown vertically oriented graphene nanoparticle movement restriction.

    Science.gov (United States)

    Vanrenterghem, Bart; Hodnik, Nejc; Bele, Marjan; Šala, Martin; Amelinckx, Giovanni; Neukermans, Sander; Zaplotnik, Rok; Primc, Gregor; Mozetič, Miran; Breugelmans, Tom

    2017-08-17

    Beside activity, electrocatalyst stability is gaining in importance. The most common degradation mechanism is the loss of the active surface area due to nanoparticle growth via coalescence/agglomeration. We propose a particle confinement strategy via vertically oriented graphene deposition to overcome degradation of the nanoparticles.

  19. Ultimately short ballistic vertical graphene Josephson junctions

    Science.gov (United States)

    Lee, Gil-Ho; Kim, Sol; Jhi, Seung-Hoon; Lee, Hu-Jong

    2015-01-01

    Much efforts have been made for the realization of hybrid Josephson junctions incorporating various materials for the fundamental studies of exotic physical phenomena as well as the applications to superconducting quantum devices. Nonetheless, the efforts have been hindered by the diffusive nature of the conducting channels and interfaces. To overcome the obstacles, we vertically sandwiched a cleaved graphene monoatomic layer as the normal-conducting spacer between superconducting electrodes. The atomically thin single-crystalline graphene layer serves as an ultimately short conducting channel, with highly transparent interfaces with superconductors. In particular, we show the strong Josephson coupling reaching the theoretical limit, the convex-shaped temperature dependence of the Josephson critical current and the exceptionally skewed phase dependence of the Josephson current; all demonstrate the bona fide short and ballistic Josephson nature. This vertical stacking scheme for extremely thin transparent spacers would open a new pathway for exploring the exotic coherence phenomena occurring on an atomic scale. PMID:25635386

  20. Alignment analysis of a vertical sodium pump

    International Nuclear Information System (INIS)

    Gupta, V.K.; Fair, C.E.

    1981-01-01

    With the objective of identifying important alignment features of pumps such as FFTF, HALLAM, EBR II, PNC, PHENIX, and CRBR, alignment of the vertical sodium pump for the Clinch River Breeder Reactor Plant (CRBRP) is investigated. The CRBRP pump includes a flexibly coupled pump shaft and motor shaft, two oil-film tilting-pad hydrodynamic radial bearings in the motor plus a vertical thrust bearing, and two sodium hydrostatic bearings straddling the double-suction centrifugal impeller in the pump. The assembled CRBRP prototype pump shows smooth predictable vibration behavior experienced during water test. An ealier swing check of the pump shaft about the motor shaft hub demonstrated that the pump is relatively insensitive to manufacturing and assembly tolerances, a consequence of close dimensional control and unique alignment features. (orig./GL)

  1. Asymmetric SOL Current in Vertically Displaced Plasma

    Science.gov (United States)

    Cabrera, J. D.; Navratil, G. A.; Hanson, J. M.

    2017-10-01

    Experiments at the DIII-D tokamak demonstrate a non-monotonic relationship between measured scrape-off layer (SOL) currents and vertical displacement event (VDE) rates with SOL currents becoming largely n=1 dominant as plasma is displaced by the plasma control system (PCS) at faster rates. The DIII-D PCS is used to displace the magnetic axis 10x slower than the intrinsic growth time of similar instabilities in lower single-null plasmas. Low order (n VDE instabilities observed when vertical control is disabled. Previous inquiry shows VDE asymmetry characterized by SOL current fraction and geometric parameters of tokamak plasmas. We note that, of plasmas displaced by the PCS, short displacement time scales near the limit of the PCS temporal control appear to result in larger n=1/n=2 asymmetries. Work supported under USDOE Cooperative Agreement DE-FC02-04ER54698 and DE-FG02-04ER54761.

  2. Round beams generated by vertical dispersion

    International Nuclear Information System (INIS)

    Bagley, P.

    1990-01-01

    Simulations suggest that in e + e - storage rings collisions of round beams (equal emittances and equal β*) can produce very large tune shifts and luminosities. We understand how to make equal β*s, but generating equal emittances is more difficult. We describe an equal emittance scheme that uses several skew quads to couple horizontal dispersion into vertical dispersion. These skew quads also produce a coupling bump. At the interaction point and at other points outside the coupling bump, the motion is not coupled, so that the 'A' normal mode corresponds to horizontal motion and the 'B' normal mode corresponds to vertical motion. We present a round beam lattice for CESR that incorporates this scheme

  3. Escrita Escolar Brasileira: a escrita vertical

    Directory of Open Access Journals (Sweden)

    Carlos André Xavier Villela

    2014-12-01

    Full Text Available O exame grafoscópico visa essencialmente a determinar se duas escritas partiram ou não de um mesmo punho. A fim de buscar dados empíricos capazes de melhor embasar uma valoração de raridade, diversos pesquisadores se dedicaram ao estudo dos sistemas de escrita. O presente trabalho analisa algumas bibliografias nacionais e estrangeiras que descrevem como se deu o alvorecer da escrita vertical e sua implantação no universo escolar brasileiro. Foi a partir das últimas décadas do século XIX que alógrafos cursivos verticais começaram a ser utilizados para o ensino da escrita. Os novos sistemas, sob a denominação escrita vertical, tiveram presença marcante em todo o mundo ocidental, sendo até hoje os sistemas predominantes em diversos países.

  4. Equilibrium vertical field in the TBR Tokamak

    International Nuclear Information System (INIS)

    Ueta, A.Y.

    1985-01-01

    An experimental study on the influence of the vertical magnetic field of the TBR tokamak on the stability and equilibrium of plasma column, was done. Magnetic pick-up coils were built to measure plasma current and position, together with active networks, necessary fo the electronic processing of signals. Some measurements were on the space configuration of the vertical field, and on the influence due to the toroidal vessel. From the data obtained it was possible to discuss the influence of the currents induced on the vessel surface, on plasma equilibrium. Theoretical and experimental results of the vertica field, as a function of plasma current were compared, and allowed an evaluation of the plasma kinetic pressure and temperature. (Author) [pt

  5. High-Performance Vertical Organic Electrochemical Transistors.

    Science.gov (United States)

    Donahue, Mary J; Williamson, Adam; Strakosas, Xenofon; Friedlein, Jacob T; McLeod, Robert R; Gleskova, Helena; Malliaras, George G

    2018-02-01

    Organic electrochemical transistors (OECTs) are promising transducers for biointerfacing due to their high transconductance, biocompatibility, and availability in a variety of form factors. Most OECTs reported to date, however, utilize rather large channels, limiting the transistor performance and resulting in a low transistor density. This is typically a consequence of limitations associated with traditional fabrication methods and with 2D substrates. Here, the fabrication and characterization of OECTs with vertically stacked contacts, which overcome these limitations, is reported. The resulting vertical transistors exhibit a reduced footprint, increased intrinsic transconductance of up to 57 mS, and a geometry-normalized transconductance of 814 S m -1 . The fabrication process is straightforward and compatible with sensitive organic materials, and allows exceptional control over the transistor channel length. This novel 3D fabrication method is particularly suited for applications where high density is needed, such as in implantable devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Soft soils reinforced by rigid vertical inclusions

    Directory of Open Access Journals (Sweden)

    Iulia-Victoria NEAGOE

    2013-12-01

    Full Text Available Reinforcement of soft soils by rigid vertical inclusions is an increasingly used technique over the last few years. The system consists of rigid or semi-rigid vertical inclusions and a granular platform for the loads transfer from the structure to the inclusions. This technique aims to reduce the differential settlements both at ground level as below the structure. Reinforcement by rigid inclusions is mainly used for foundation works for large commercial and industrial platforms, storage tanks, wastewater treatment plants, wind farms, bridges, roads, railway embankments. The subject is one of interest as it proves the recently concerns at international level in research and design; however, most studies deal more with the static behavior and less with the dynamic one.

  7. Interaction vertices in reduced string field theories

    International Nuclear Information System (INIS)

    Embacher, F.

    1989-01-01

    In contrast to previous expectations, covariant overlap vertices are not always suitable for gauge-covariant formulations of bosonic string field theory with a reduced supplementary field content. This is demonstrated for the version of the theory suggested by Neveu, Schwarz and West. The method to construct the interaction, as formulated by Neveu and West, fails at one level higher than these authors have considered. The condition for a general vertex to describe formally a local gauge-invariant interaction is derived. The solution for the action functional and the gauge transformation law is exhibited for all fields at once, to the first order in the coupling constant. However, all these vertices seem to be unphysical. 21 refs. (Author)

  8. Electrically floating, near vertical incidence, skywave antenna

    Science.gov (United States)

    Anderson, Allen A.; Kaser, Timothy G.; Tremblay, Paul A.; Mays, Belva L.

    2014-07-08

    An Electrically Floating, Near Vertical Incidence, Skywave (NVIS) Antenna comprising an antenna element, a floating ground element, and a grounding element. At least part of said floating ground element is positioned between said antenna element and said grounding element. The antenna is separated from the floating ground element and the grounding element by one or more electrical insulators. The floating ground element is separated from said antenna and said grounding element by one or more electrical insulators.

  9. RADIALLY MAGNETIZED PROTOPLANETARY DISK: VERTICAL PROFILE

    International Nuclear Information System (INIS)

    Russo, Matthew; Thompson, Christopher

    2015-01-01

    This paper studies the response of a thin accretion disk to an external radial magnetic field. Our focus is on protoplanetary disks (PPDs), which are exposed during their later evolution to an intense, magnetized wind from the central star. A radial magnetic field is mixed into a thin surface layer, wound up by the disk shear, and pushed downward by a combination of turbulent mixing and ambipolar and ohmic drift. The toroidal field reaches much greater strengths than the seed vertical field that is usually invoked in PPD models, even becoming superthermal. Linear stability analysis indicates that the disk experiences the magnetorotational instability (MRI) at a higher magnetization than a vertically magnetized disk when both the effects of ambipolar and Hall drift are taken into account. Steady vertical profiles of density and magnetic field are obtained at several radii between 0.06 and 1 AU in response to a wind magnetic field B r ∼ (10 −4 –10 −2 )(r/ AU) −2 G. Careful attention is given to the radial and vertical ionization structure resulting from irradiation by stellar X-rays. The disk is more strongly magnetized closer to the star, where it can support a higher rate of mass transfer. As a result, the inner ∼1 AU of a PPD is found to evolve toward lower surface density. Mass transfer rates around 10 −8 M ⊙ yr −1 are obtained under conservative assumptions about the MRI-generated stress. The evolution of the disk and the implications for planet migration are investigated in the accompanying paper

  10. RADIALLY MAGNETIZED PROTOPLANETARY DISK: VERTICAL PROFILE

    Energy Technology Data Exchange (ETDEWEB)

    Russo, Matthew [Department of Physics, University of Toronto, 60 St. George St., Toronto, ON M5S 1A7 (Canada); Thompson, Christopher [Canadian Institute for Theoretical Astrophysics, 60 St. George St., Toronto, ON M5S 3H8 (Canada)

    2015-11-10

    This paper studies the response of a thin accretion disk to an external radial magnetic field. Our focus is on protoplanetary disks (PPDs), which are exposed during their later evolution to an intense, magnetized wind from the central star. A radial magnetic field is mixed into a thin surface layer, wound up by the disk shear, and pushed downward by a combination of turbulent mixing and ambipolar and ohmic drift. The toroidal field reaches much greater strengths than the seed vertical field that is usually invoked in PPD models, even becoming superthermal. Linear stability analysis indicates that the disk experiences the magnetorotational instability (MRI) at a higher magnetization than a vertically magnetized disk when both the effects of ambipolar and Hall drift are taken into account. Steady vertical profiles of density and magnetic field are obtained at several radii between 0.06 and 1 AU in response to a wind magnetic field B{sub r} ∼ (10{sup −4}–10{sup −2})(r/ AU){sup −2} G. Careful attention is given to the radial and vertical ionization structure resulting from irradiation by stellar X-rays. The disk is more strongly magnetized closer to the star, where it can support a higher rate of mass transfer. As a result, the inner ∼1 AU of a PPD is found to evolve toward lower surface density. Mass transfer rates around 10{sup −8} M{sub ⊙} yr{sup −1} are obtained under conservative assumptions about the MRI-generated stress. The evolution of the disk and the implications for planet migration are investigated in the accompanying paper.

  11. Assessing verticalization effects on urban safety perception

    OpenAIRE

    Lourenço, Ricardo Barros

    2017-01-01

    We describe an experiment with the modeling of urban verticalization effects on perceived safety scores as obtained with computer vision on Google Streetview data for New York City. Preliminary results suggests that for smaller buildings (between one and seven floors), perceived safety increases with building height, but that for high-rise buildings, perceived safety decreases with increased height. We also determined that while height contributing for this relation, other zonal aspects also ...

  12. Vertical Integration Versus Outsourcing in Industry Equilibrium

    OpenAIRE

    Bin Wang

    2006-01-01

    We study the determinants of the extent of in-house vertical integration and of outsourcing in foreign countries. Potential suppliers must make a relationship-specific investment in order to serve each prospective customer. Such investments are governed by imperfect contracts. A final-good producer can manufacture components for it, but the per-unit cost is higher than for specialized suppliers. We consider how the size of the cost differential, the trade costs of components, the relative cos...

  13. Vertical Integration in the Taiwan Aquaculture Industry

    OpenAIRE

    Tzong-Ru Lee (Jiun-Shen); Yi-Hsu; Cheng-Jen Lin; Kongkiti Phusavat; Nirote Sinnarong

    2011-01-01

    The study aims to improve the distribution channels in the Taiwan aquaculture industry through a better vertical integration. This study is derived from a need to improve the distribution performance of agricultural-based industries in response to increasing food demands in Asia and elsewhere. Based on a four-by-eight matrix derived from both a value chain and a service profit chain, thirty different strategies are developed. This development is based on key success factors and strategies for...

  14. Vertical integration technologies for vertex detectors

    International Nuclear Information System (INIS)

    Ratti, L.

    2011-01-01

    This work is focused on the use of vertical integration (3D) technologies in the design of hybrid or monolithic pixel detectors in view of applications to silicon vertex trackers (SVTs) at the future high luminosity colliders. After a short introduction on the specifications of next-generation SVTs, the paper will discuss the general features of 3D microelectronic processes and the benefits they can provide to the design of pixel detectors for high energy physics experiments.

  15. Vertical hydraulic transport of particulate solids

    International Nuclear Information System (INIS)

    Restini, C.V.; Massarani, G.

    1977-01-01

    The problem of particulate solid vertical transport is formulated using the conservation equations of Continuum Mechanics. It is shown that the constitutive equation for solid-fluid interaction term in the equations of motion may be determined by rather simple experiments of homogeneous fluidization. The predicted fluid pressure drop and solid concentration are in satisfacting agreement with past experiments and with data obtained in this work. (Author) [pt

  16. Data driven modelling of vertical atmospheric radiation

    International Nuclear Information System (INIS)

    Antoch, Jaromir; Hlubinka, Daniel

    2011-01-01

    In the Czech Hydrometeorological Institute (CHMI) there exists a unique set of meteorological measurements consisting of the values of vertical atmospheric levels of beta and gamma radiation. In this paper a stochastic data-driven model based on nonlinear regression and on nonhomogeneous Poisson process is suggested. In the first part of the paper, growth curves were used to establish an appropriate nonlinear regression model. For comparison we considered a nonhomogeneous Poisson process with its intensity based on growth curves. In the second part both approaches were applied to the real data and compared. Computational aspects are briefly discussed as well. The primary goal of this paper is to present an improved understanding of the distribution of environmental radiation as obtained from the measurements of the vertical radioactivity profiles by the radioactivity sonde system. - Highlights: → We model vertical atmospheric levels of beta and gamma radiation. → We suggest appropriate nonlinear regression model based on growth curves. → We compare nonlinear regression modelling with Poisson process based modeling. → We apply both models to the real data.

  17. Rotation of vertically oriented objects during earthquakes

    Science.gov (United States)

    Hinzen, Klaus-G.

    2012-10-01

    Vertically oriented objects, such as tombstones, monuments, columns, and stone lanterns, are often observed to shift and rotate during earthquake ground motion. Such observations are usually limited to the mesoseismal zone. Whether near-field rotational ground motion components are necessary in addition to pure translational movements to explain the observed rotations is an open question. We summarize rotation data from seven earthquakes between 1925 and 2009 and perform analog and numeric rotation testing with vertically oriented objects. The free-rocking motion of a marble block on a sliding table is disturbed by a pulse in the direction orthogonal to the rocking motion. When the impulse is sufficiently strong and occurs at the `right' moment, it induces significant rotation of the block. Numeric experiments of a free-rocking block show that the initiation of vertical block rotation by a cycloidal acceleration pulse applied orthogonal to the rocking axis depends on the amplitude of the pulse and its phase relation to the rocking cycle. Rotation occurs when the pulse acceleration exceeds the threshold necessary to provoke rocking of a resting block, and the rocking block approaches its equilibrium position. Experiments with blocks subjected to full 3D strong motion signals measured during the 2009 L'Aquila earthquake confirm the observations from the tests with analytic ground motions. Significant differences in the rotational behavior of a monolithic block and two stacked blocks exist.

  18. Human sensitivity to vertical self-motion.

    Science.gov (United States)

    Nesti, Alessandro; Barnett-Cowan, Michael; Macneilage, Paul R; Bülthoff, Heinrich H

    2014-01-01

    Perceiving vertical self-motion is crucial for maintaining balance as well as for controlling an aircraft. Whereas heave absolute thresholds have been exhaustively studied, little work has been done in investigating how vertical sensitivity depends on motion intensity (i.e., differential thresholds). Here we measure human sensitivity for 1-Hz sinusoidal accelerations for 10 participants in darkness. Absolute and differential thresholds are measured for upward and downward translations independently at 5 different peak amplitudes ranging from 0 to 2 m/s(2). Overall vertical differential thresholds are higher than horizontal differential thresholds found in the literature. Psychometric functions are fit in linear and logarithmic space, with goodness of fit being similar in both cases. Differential thresholds are higher for upward as compared to downward motion and increase with stimulus intensity following a trend best described by two power laws. The power laws' exponents of 0.60 and 0.42 for upward and downward motion, respectively, deviate from Weber's Law in that thresholds increase less than expected at high stimulus intensity. We speculate that increased sensitivity at high accelerations and greater sensitivity to downward than upward self-motion may reflect adaptations to avoid falling.

  19. Measurement of vertical stability metrics in KSTAR

    Science.gov (United States)

    Hahn, Sang-Hee; Humphreys, D. A.; Mueller, D.; Bak, J. G.; Eidietis, N. W.; Kim, H.-S.; Ko, J. S.; Walker, M. L.; Kstar Team

    2017-10-01

    The paper summarizes results of multi-year ITPA experiments regarding measurement of the vertical stabilization capability of KSTAR discharges, including most recent measurements at the highest achievable elongation (κ 2.0 - 2.1). The measurements of the open-loop growth rate of VDE (γz) and the maximum controllable vertical displacement (ΔZmax) are done by the release-and-catch method. The dynamics of the vertical movement of the plasma is verified by both relevant magnetic reconstructions and non-magnetic diagnostics. The measurements of γz and ΔZmax were done for different plasma currents, βp, internal inductances, elongations and different configurations of the vessel conductors that surround the plasma as the first wall. Effects of control design choice and diagnostics noise are discussed, and comparison with the axisymmetric plasma response model is given for partial accounting for the measured control capability. This work supported by Ministry of Science, ICT, and Future Planning under KSTAR project.

  20. Feedback control of vertical instability in TNS

    International Nuclear Information System (INIS)

    Frantz, E.R.

    1978-05-01

    Due to the unfavorable curvature of the vertical vacuum magnetic field, elongated plasmas are vertically unstable when the elongation, epsilon, becomes too large. The TNS (The Next Step) tokamak, as evolved in the Westinghouse-ORNL studies has an inside-D configuration (epsilon = 1.6, A = 5/1.25 = 4) characterized by an average decay index n approximately equal -0.75 at the plasma flux surface near the magnetic axis and is vertically unstable with a growth rate γ 0 approximately 10 5 sec -1 . Eddy currents produced in the vacuum vessel wall will slow this instability to growth rates γ 0 approximately 10 2 sec -1 provided there are no transverse insulating gaps in the vessel wall. A matrix equation has been developed for calculating the eddy currents induced in the EF coils and their stabilizing effect. Control theory for feedback systems with and without delay time is presented and possible plasma position detectors are discussed. For a plasma current of 6.1 MA, the controller peak power requirements using separate controller circuits are approximately 1 MW depending upon EF coil configurations and time delay. This feedback system is designed to stabilize a maximum plasma excursion of 10 cm from the midplane with delay times up to 2 sec

  1. TFTR vertically viewing electron cyclotron emission diagnostic

    International Nuclear Information System (INIS)

    Taylor, G.

    1990-01-01

    The Tokamak Fusion Test Reactor (TFTR) Michelson interferometer has a spectral coverage of 75--540 GHz, allowing measurement of the first four electron cyclotron harmonics. Until recently the instrument has been configured to view the TFTR plasma on the horizontal midplane, primarily in order to measure the electron temperature profile. Electron cyclotron emission (ECE) extraordinary mode spectra from TFTR Supershot plasmas exhibit a pronounced, spectrally narrow feature below the second harmonic. A similar feature is seen with the ECE radiometer diagnostic below the electron cyclotron fundamental frequency in the ordinary mode. Analysis of the ECE spectra indicates the possibility of a non-Maxwellian 40--80 keV tail on the electron distribution in or near the core. During 1990 three vertical views with silicon carbide viewing targets will be installed to provide a direct measurement of the electron energy distribution at major radii of 2.54, 2.78, and 3.09 m with an energy resolution of approximately 20% at 100 keV. To provide the maximum flexibility, the optical components for the vertical views will be remotely controlled to allow the Michelson interferometer to be reconfigured to either the midplane horizontal view or one of the three vertical views between plasma shots

  2. Vertical and horizontal seismometric observations of tides

    Science.gov (United States)

    Lambotte, S.; Rivera, L.; Hinderer, J.

    2006-01-01

    Tidal signals have been largely studied with gravimeters, strainmeters and tiltmeters, but can also be retrieved from digital records of the output of long-period seismometers, such as STS-1, particularly if they are properly isolated. Horizontal components are often noisier than the vertical ones, due to sensitivity to tilt at long periods. Hence, horizontal components are often disturbed by local effects such as topography, geology and cavity effects, which imply a strain-tilt coupling. We use series of data (duration larger than 1 month) from several permanent broadband seismological stations to examine these disturbances. We search a minimal set of observable signals (tilts, horizontal and vertical displacements, strains, gravity) necessary to reconstruct the seismological record. Such analysis gives a set of coefficients (per component for each studied station), which are stable over years and then can be used systematically to correct data from these disturbances without needing heavy numerical computation. A special attention is devoted to ocean loading for stations close to oceans (e.g. Matsushiro station in Japon (MAJO)), and to pressure correction when barometric data are available. Interesting observations are made for vertical seismometric components; in particular, we found a pressure admittance between pressure and data 10 times larger than for gravimeters for periods larger than 1 day, while this admittance reaches the usual value of -3.5 nm/s 2/mbar for periods below 3 h. This observation may be due to instrumental noise, but the exact mechanism is not yet understood.

  3. Algebraic motion of vertically displacing plasmas

    Science.gov (United States)

    Pfefferlé, D.; Bhattacharjee, A.

    2018-02-01

    The vertical motion of a tokamak plasma is analytically modelled during its non-linear phase by a free-moving current-carrying rod inductively coupled to a set of fixed conducting wires or a cylindrical conducting shell. The solutions capture the leading term in a Taylor expansion of the Green's function for the interaction between the plasma column and the surrounding vacuum vessel. The plasma shape and profiles are assumed not to vary during the vertical drifting phase such that the plasma column behaves as a rigid body. In the limit of perfectly conducting structures, the plasma is prevented to come in contact with the wall due to steep effective potential barriers created by the induced Eddy currents. Resistivity in the wall allows the equilibrium point to drift towards the vessel on the slow timescale of flux penetration. The initial exponential motion of the plasma, understood as a resistive vertical instability, is succeeded by a non-linear "sinking" behaviour shown to be algebraic and decelerating. The acceleration of the plasma column often observed in experiments is thus concluded to originate from an early sharing of toroidal current between the core, the halo plasma, and the wall or from the thermal quench dynamics precipitating loss of plasma current.

  4. Dynamic stiffness of suction caissons - vertical vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Ibsen, Lars Bo; Liingaard, M.; Andersen, Lars

    2006-12-15

    The dynamic response of offshore wind turbines are affected by the properties of the foundation and the subsoil. The purpose of this report is to evaluate the dynamic soil-structure interaction of suction caissons for offshore wind turbines. The investigation is limited to a determination of the vertical dynamic stiffness of suction caissons. The soil surrounding the foundation is homogenous with linear viscoelastic properties. The dynamic stiffness of the suction caisson is expressed by dimensionless frequency-dependent dynamic stiffness coefficients corresponding to the vertical degree of freedom. The dynamic stiffness coefficients for the foundations are evaluated by means of a dynamic three-dimensional coupled Boundary Element/Finite Element model. Comparisons are made with known analytical and numerical solutions in order to evaluate the static and dynamic behaviour of the Boundary Element/Finite Element model. The vertical frequency dependent stiffness has been determined for different combinations of the skirt length, Poisson's ratio and the ratio between soil stiffness and skirt stiffness. Finally the dynamic behaviour at high frequencies is investigated. (au)

  5. Case history: Vertical barrier wall system for Superfund Site

    International Nuclear Information System (INIS)

    Koelling, M.A.; Kovac, C.P.; Norris, J.E.

    1997-01-01

    Design considerations and construction aspects are presented for the installation of a vertical barrier wall system for the Boeing Company at a Superfund Site near Seattle, WA. The construction was performed during 1996. The vertical barrier wall system included: (1) a soil-bentonite (SB) slurry wall, approximately 670 meters (2200 feet) in length, ranging from 12 to 21 meters (40 to 70 feet) in depth; (2) expansion of a cover system over the area enclosed by the SB wall; and (3) surface drainage improvements. Design and construction of the system addressed requirements of a Consent Decree for the site issued in 1993. The paper discusses the development of the design to meet remedial performance goals of preventing migration of contaminants in the soil/groundwater system and aiding aquifer restoration. Secondly, the paper details installation of the SB wall, highlighting the more significant construction issues, which included excavation of the wall through glacially deposited cobbles/boulders/till as well as addressing the severe elevation changes along the wall alignment. Thirdly, the paper presents Quality Assurance (QA) monitoring and testing performed during the construction phase

  6. FFTF vertical sodium storage tank preliminary thermal analysis

    International Nuclear Information System (INIS)

    Irwin, J.J.

    1995-01-01

    In the FFTF Shutdown Program, sodium from the primary and secondary heat transport loops, Interim Decay Storage (IDS), and Fuel Storage Facility (FSF) will be transferred to four large storage tanks for temporary storage. Three of the storage tanks will be cylindrical vertical tanks having a diameter of 28 feet, height of 22 feet and fabricated from carbon steel. The fourth tank is a horizontal cylindrical tank but is not the subject of this report. The storage tanks will be located near the FFTF in the 400 Area and rest on a steel-lined concrete slab in an enclosed building. The purpose of this work is to document the thermal analyses that were performed to ensure that the vertical FFTF sodium storage tank design is feasible from a thermal standpoint. The key criterion for this analysis is the time to heat up the storage tank containing frozen sodium at ambient temperature to 400 F. Normal operating conditions include an ambient temperature range of 32 F to 120 F. A key parameter in the evaluation of the sodium storage tank is the type of insulation. The baseline case assumed six inches of calcium silicate insulation. An alternate case assumed refractory fiber (Cerablanket) insulation also with a thickness of six inches. Both cases assumed a total electrical trace heat load of 60 kW, with 24 kW evenly distributed on the bottom head and 36 kW evenly distributed on the tank side wall

  7. Characterisation of microbial biocoenosis in vertical subsurface flow constructed wetlands

    International Nuclear Information System (INIS)

    Tietz, Alexandra; Kirschner, Alexander; Langergraber, Guenter; Sleytr, Kirsten; Haberl, Raimund

    2007-01-01

    In this study a quantitative description of the microbial biocoenosis in subsurface vertical flow constructed wetlands fed with municipal wastewater was carried out. Three different methods (substrate induced respiration, ATP measurement and fumigation-extraction) were applied to measure the microbial biomass at different depths of planted and unplanted systems. Additionally, bacterial biomass was determined by epifluorescence microscopy and productivity was measured via 14 C leucine incorporation into bacterial biomass. All methods showed that > 50% of microbial biomass and bacterial activity could be found in the first cm and about 95% in the first 10 cm of the filter layer. Bacterial biomass in the first 10 cm of the filter body accounted only for 16-19% of the total microbial biomass. Whether fungi or methodical uncertainties are mainly responsible for the difference between microbial and bacterial biomass remains to be examined. A comparison between the purification performance of planted and unplanted pilot-scale subsurface vertical flow constructed wetlands (PSCWs) showed no significant difference with the exception of the reduction of enterococci. The microbial biomass in all depths of the filter body was also not different in planted and unplanted systems. Compared with data from soils the microbial biomass in the PSCWs was high, although the specific surface area of the used sandy filter material available for biofilm growth was lower, especially in the beginning of the set-up of the PSCWs, due to missing clay and silt fraction

  8. Experimental studies of PWR vertical steam generator performance

    International Nuclear Information System (INIS)

    Ding Xunshen

    1998-06-01

    The characteristics of heat transfer, natural circulation and moisture separation equipment with a vertical steam generator model are tested on a high-temperature and high-pressure test facility. The primary loop pipe is made of low alloy steel. the primary water at 10.13 MPa is driven by two centrifugal pumps. Boiler is designed to elevate the primary water temperature by 60 degree C at a flow rate of 65 t/h. The test model can produce a maximum steam flow of 8 t/h; 240 stainless steel U tubes are invert connected with the tubesheet, the tube dimensions are φ15 mm x 1.5 mm. The model has a height of 5.789 m. Heat transfer characteristics experiment is obtained: The steam generator thermal design can neglect the existence of preheating region, considering the saturated boiling takes place over all the tube surface. This does not exactly reflect the actual heat transfer coefficient and temperature difference. But, the product of two parameters is lower for design than for experiment so that heat transfer coefficient and temperature difference combine to result in a larger heat transfer area for design than for experiment. Moisture separator is a swirl vane separator. Dryer is a single circle of vertical chevron plate separator. Test results indicate the separation efficiency of the moisture separator and dryer is very satisfactory and the exit moisture is much better than 0.25% (the required content)

  9. Retrieving Vertical Air Motion and Raindrop Size Distributions from Vertically Pointing Doppler Radars

    Science.gov (United States)

    Williams, C. R.; Chandra, C. V.

    2017-12-01

    The vertical evolution of falling raindrops is a result of evaporation, breakup, and coalescence acting upon those raindrops. Computing these processes using vertically pointing radar observations is a two-step process. First, the raindrop size distribution (DSD) and vertical air motion need to be estimated throughout the rain shaft. Then, the changes in DSD properties need to be quantified as a function of height. The change in liquid water content is a measure of evaporation, and the change in raindrop number concentration and size are indicators of net breakup or coalescence in the vertical column. The DSD and air motion can be retrieved using observations from two vertically pointing radars operating side-by-side and at two different wavelengths. While both radars are observing the same raindrop distribution, they measure different reflectivity and radial velocities due to Rayleigh and Mie scattering properties. As long as raindrops with diameters greater than approximately 2 mm are in the radar pulse volumes, the Rayleigh and Mie scattering signatures are unique enough to estimate DSD parameters using radars operating at 3- and 35-GHz (Williams et al. 2016). Vertical decomposition diagrams (Williams 2016) are used to explore the processes acting on the raindrops. Specifically, changes in liquid water content with height quantify evaporation or accretion. When the raindrops are not evaporating, net raindrop breakup and coalescence are identified by changes in the total number of raindrops and changes in the DSD effective shape as the raindrops. This presentation will focus on describing the DSD and air motion retrieval method using vertical profiling radar observations from the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) central facility in Northern Oklahoma.

  10. Oceanic diffusion in the coastal area

    International Nuclear Information System (INIS)

    Rukuda, Masaaki

    1980-03-01

    Described in this paper is the eddy diffusion in the area off Tokai Village investigated by means of dye diffusion experiment and of oceanic observation. In order to assess the oceanic diffusion in coastal areas, improved methods effective in complex field were developed. The oceanic diffusion was separated in two groups, horizontal and vertical diffusion respectively. Both these diffusions are combined and their analysis together is difficult. The oceanic diffusion is thus considered separately. Instantaneous point release is the basis of horizontal diffusion analysis. Continuous release is then the overlap of numerous instantaneous releases. It was shown that the diffusion parameters derived from the results of diffusion experiment or oceanic observation vary widely with time and place and with sea conditions. A simple diffusion equation was developed from the equation of continuity. The results were in good agreement with seasonal mean horizontal distribution of river water in the sea area. The vertical observation in diffusion experiment is difficult and the vertical structure of oceanic condition is complex, so that the research on vertical diffusion generally is not advanced yet. With river water as the tracer, a method of estimating vertical diffusion parameters with a Gaussian model or one-dimensional model was developed. The vertical diffusion near sea bottom was numerically analized with suspended particles in seawater as the tracer. Diffusion was computed for each particle size, and by summing up the vertical distribution of beam attenuation coefficient was estimated. By comparing the results of estimation and those of observation the vertical diffusivity and the particle size distribution at sea bottom could be estimated. (author)

  11. clınıcal EVALUATION OF FREE GINGIVAL GRAFT SHRINKAGE IN HORIZONTAL AND VERTICAL DIMENSIONS

    Directory of Open Access Journals (Sweden)

    Emine ÇİFCİBAŞI

    2015-10-01

    Full Text Available Purpose: To assess the shrinkage of Free Gingival Graft (FGG in horizontal and vertical dimensions and calculate the changes in the surface area of the transplanted tissue in a 3 months period. Materials and Methods: A total of 30 FGG were placed aiming to increase attached gingiva around recession sites. Vertical recessions, horizontal recessions, surface area, plaque index, gingival index, periodontal probing depth and clinical attachment level were assesed at baseline, 1 and 3 months postoperatively. Results: Graft shrinkage between baseline and 1 month was more evident than 1 to 3 months in either dimensions. Both horizontal and vertical dimensions were significantly decreased (p0.05. . Conclusion: The shrinkage of vertical and horizontal dimensions of the grafts were almost equal unlike the literature. In addition, the different dimensional changes observed in individual level deserve further research.

  12. ostglacial rebound from VLBI Geodesy: On Establishing Vertical Reference

    Science.gov (United States)

    Argus, Donald .

    1996-01-01

    I propose that a useful reference frame for vertical motions is that found by minimizing differences between vertical motions observed with VLBI [Ma and Ryan, 1995] and predictions from postglacial rebound predictions [Peltier, 1995].

  13. Vertically aligned carbon nanotube field-effect transistors

    KAUST Repository

    Li, Jingqi; Zhao, Chao; Wang, Qingxiao; Zhang, Qiang; Wang, Zhihong; Zhang, Xixiang; Abutaha, Anas I.; Alshareef, Husam N.

    2012-01-01

    Vertically aligned carbon nanotube field-effect transistors (CNTFETs) have been developed using pure semiconducting carbon nanotubes. The source and drain were vertically stacked, separated by a dielectric, and the carbon nanotubes were placed

  14. Going Up? The Pros and Cons of Vertical Expansion.

    Science.gov (United States)

    Myler, Patricia A.; Boggs, Richard C.

    2002-01-01

    Describes the advantages and disadvantages of the vertical expansion of school buildings. Considers such factors as fire protection, compliance with the Americans with Disabilities Act, and cost. Discusses alternatives to vertical expansion. (PKP)

  15. Tolerances for the vertical emittance in damping rings

    International Nuclear Information System (INIS)

    Raubenheimer, T.O.

    1991-11-01

    Future damping rings for linear colliders will need to have very small vertical emittances. In the limit of low beam current, the vertical emittance is primarily determined by the vertical dispersion and the betatron coupling. In this paper, the contributions to these effects from random misalignments are calculated and tolerances are derived to limit the vertical emittance with a 95% confidence level. 10 refs., 5 figs

  16. The correction of occlusal vertical dimension on tooth wear

    Directory of Open Access Journals (Sweden)

    Rostiny Rostiny

    2007-12-01

    Full Text Available The loss of occlusal vertical dimension which is caused by tooth wear is necessarily treated to regain vertical dimension. Correctional therapy should be done as early possible. In this case, simple and relatively low cost therapy was performed. In unserve loss of occlusal vertical dimension, partial removable denture could be used and the improvement of lengthening anterior teeth using composite resin to improve to regain vertical dimensional occlusion.

  17. Vertical specialization and industrial upgrading: a preliminary note

    OpenAIRE

    Xiao Jiang; William Milberg

    2012-01-01

    Abstract Vertical specialization is a measure of the import content of exports. Given the widely recognized importance of trade in tasks and global production networks, vertical specialization has recently gained the attention of international trade researchers and policy makers. In this note, we use measured changes in the within-country pattern of vertical specialization to gauge the relevance of task trade for industrial upgrading and economic development. We first calculate vertical speci...

  18. Vertical and horizontal seismic profiling investigations at Olkiluoto, 2001

    Energy Technology Data Exchange (ETDEWEB)

    Cosma, C.; Enescu, N.; Adam, E.; Balu, L. [Vibrometric Oy (Finland)

    2003-03-01

    Vertical Seismic Profiling (VSP) and Horizontal Seismic Profiling (HSP) surveys were conducted during 2001 at Olkiluoto site in Eurajoki, Finland. The VSP investigations were carried out in four boreholes with ten shot points for each borehole. Two HSP lines were measured with receivers laid on the bottom of an artificial pond and ten source points located around the pond. Different receiver types were used for the VSP and (HSP) a 3-component geophone chain for VSP and a hydrophone chain for HSP. All surveys have been carried out with a VIBSIST-1000 source - a time- distributed swept-impact source - instead of explosives. With this source, the seismic signals are produced as rapid series of impacts, the impact intervals being monotonically increased to achieve a non- repeatable sequence. The VIBSIST-1000 uses a tractor-mounted hydraulic rock-breaker, powered through a computer controlled servo- hydraulic flow regulator. Using standard construction equipment ensures that the VIBSIST sources are safe, nondestructive and environmentally friendly. This also makes the method reliable and cost effective. The new VIBSIST source produces signals with levels of energy comparable to explosives. The VIBSIST appears to be more stable, but its most significant advantages are the low cost of preparation of the shot points and the speed of the acquisition. The wide diversity of reflection angles, the local variations of reflectivity and, generally, the relatively weak seismic response of faults and fractured zones in crystalline rock demand intensive processing. The first stage of the processing sequence focuses on eliminating such wave-fields as the direct P, direct S, tube-waves and ground-roll, so that the weaker later events, e.g. reflections, become visible. The second stage of processing consists mainly of Image Point (IP) filtering techniques, aimed at enhancing the reflected wave fields and at separating events generated by reflectors with different orientations. Imaging

  19. Analysis of vertical stability limits and vertical displacement event behavior on NSTX-U

    Science.gov (United States)

    Boyer, Mark; Battaglia, Devon; Gerhardt, Stefan; Menard, Jonathan; Mueller, Dennis; Myers, Clayton; Sabbagh, Steven; Smith, David

    2017-10-01

    The National Spherical Torus Experiment Upgrade (NSTX-U) completed its first run campaign in 2016, including commissioning a larger center-stack and three new tangentially aimed neutral beam sources. NSTX-U operates at increased aspect ratio due to the larger center-stack, making vertical stabilization more challenging. Since ST performance is improved at high elongation, improvements to the vertical control system were made, including use of multiple up-down-symmetric flux loop pairs for real-time estimation, and filtering to remove noise. Similar operating limits to those on NSTX (in terms of elongation and internal inductance) were achieved, now at higher aspect ratio. To better understand the observed limits and project to future operating points, a database of vertical displacement events and vertical oscillations observed during the plasma current ramp-up on NSTX/NSTX-U has been generated. Shots were clustered based on the characteristics of the VDEs/oscillations, and the plasma parameter regimes associated with the classes of behavior were studied. Results provide guidance for scenario development during ramp-up to avoid large oscillations at the time of diverting, and provide the means to assess stability of target scenarios for the next campaign. Results will also guide plans for improvements to the vertical control system. Work supported by U.S. D.O.E. Contract No. DE-AC02-09CH11466.

  20. Test reports for K Basins vertical fuel handling tools

    Energy Technology Data Exchange (ETDEWEB)

    Meling, T.A.

    1995-02-01

    The vertical fuel handling tools, for moving N Reactor fuel elements, were tested in the 305 Building Cold Test Facility (CTF) in the 300 Area. After fabrication was complete, the tools were functionally tested in the CTF using simulated N Reactor fuel rods (inner and outer elements). The tools were successful in picking up the simulated N Reactor fuel rods. These tools were also load tested using a 62 pound dummy to test the structural integrity of each assembly. The tools passed each of these tests, based on the performance objectives. Finally, the tools were subjected to an operations acceptance test where K Basins Operations personnel operated the tool to determine its durability and usefulness. Operations personnel were satisfied with the tools. Identified open items included the absence of a float during testing, and documentation required prior to actual use of the tools in the 100 K fuel storage basin.